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Despite obvious improvements in visualization of the in vivo cornea through the faster imaging speeds and higher axial resolutions, cellular imaging stays unresolvable task for OCT, as en face viewing with a high lateral resolution is required. The latter is possible with FFOCT, a method that relies on a camera, moderate numerical aperture (NA) objectives and an incoherent light source to provide en face images with a micrometer-level resolution. Recently, we for the first time demonstrated the ability of FFOCT to capture images from the in vivo human cornea1. In the current paper we present an extensive study of appearance of healthy in vivo human corneas under FFOCT examination. En face corneal images with a micrometer-level resolution were obtained from the three healthy subjects. For each subject it was possible to acquire images through the entire corneal depth and visualize the epithelium structures, Bowman’s layer, sub-basal nerve plexus (SNP) fibers, anterior, middle and posterior stroma, endothelial cells with nuclei. Dimensions and densities of the structures visible with FFOCT, are in agreement with those seen by other cornea imaging methods. Cellular-level details in the images obtained together with the relatively large field-of-view (FOV) and contactless way of imaging make this device a promising candidate for becoming a new tool in ophthalmological diagnostics.

Purpose To use cell motility as a contrast agent in retinal explants. Methods Macaque and mouse retinal explants were imaged with high resolution full field optical coherence tomography (FFOCT) and dynamic FFOCT, coupled with fluorescence imaging. Results Static and dynamic FFOCT create complementary contrast from different structures within a cell. When imaging in vitro samples, static FFOCT detects steep refractive index gradients to reveal stationary structures including fibers, vessels, collagen, and cell contours, while dynamic FFOCT emphasizes metabolic activity of moving structures that are mainly intracellular, thus creating or enhancing contrast in cells that were previously hidden in noise. Dynamic FFOCT enables detection of most of the retinal cell types in the ganglion cell, inner and outer nuclear layers, where static FFOCT contrast is too low in relation to the noise background. Conclusions Composite static and dynamic FFOCT provides a new kind of FFOCT image containing valuable information for imaging of retinal explants. It provides label-free en face images of living retinas, with a subcellular resolution. Dynamic FFOCT adds information about cell activity, which is of interest in longitudinal explant studies.

We present a new full-field optical coherence tomography instrument capable of corneal imaging in air. Acquired images show the potential of this system for realization of in-vivo ultrahigh-resolution human cornea imaging.

The anti-epileptic drug vigabatrin induces an irreversible constriction of the visual field, but is still widely used to treat infantile spasms and some forms of epilepsy. We recently reported that vigabatrin-induced cone damage is due to a taurine deficiency. However, optic atrophy and thus retinal ganglion cell degeneration was also reported in children treated for infantile spasms. We here show in neonatal rats treated from postnatal days 4 to 29 that the vigabatrin treatment triggers not only cone photoreceptor damage, disorganisation of the photoreceptor layer and gliosis but also retinal ganglion cell loss. Furthermore, we demonstrate in these neonatal rats that taurine supplementation partially prevents these retinal lesions and in particular the retinal ganglion cell loss. These results provide the first evidence of retinal ganglion cell neuroprotection by taurine. They further confirm that taurine supplementation should be administered with the vigabatrin treatment for infantile spasms or epilepsy.

Several strategies have been proposed to restore useful vision following photoreceptor degeneration. However, a very few studies have investigated late anatomical changes and functional state of residual retinal neurons after complete photoreceptor loss. We investigated the progressive degeneration of retinal ganglion cells (RGCs) in P23H rats. The RGC multielectrode array recordings indicated lower firing rates, disappearance of broad-scale, and maintenance of short-scale pairwise correlations. Up to 11% of RGCs displayed repetitive and often correlated spike discharges, reminiscent of developmental rhythmic activity, which could be reversibly suppressed by blockade of the AMPA/kainite glutamate receptors. RGCs in P23H rats remain sensitive to local electrical stimulation, generating short-latency responses as in the normal retina. These results provide evidence that, despite the demonstrated RGC degeneration, remaining active RGCs maintain their basic physiological and network properties with some emerging functional changes such as the spontaneous rhythmic activity in late stages of the degenerative disease.

Although vigabatrin irreversibly constricts the visual field, it remains a potent therapy for infantile spasms and a third-line drug for refractory epilepsies. In albino animals, this drug induces a reduction in retinal cell function, retinal disorganization, and cone photoreceptor damage. The objective of this study was to investigate the light dependence of the vigabatrin-elicited retinal toxicity and to screen for molecules preventing this secondary effect of vigabatrin.Rats and mice were treated daily with 40 and 3mg vigabatrin, respectively. Retinal cell lesions were demonstrated by assessing cell function with electroretinogram measurements, and quantifying retinal disorganization, gliosis, and cone cell densities.Vigabatrin-elicited retinal lesions were prevented by maintaining animals in darkness during treatment. Different mechanisms including taurine deficiency were reported to produce such phototoxicity; we therefore measured amino acid plasma levels in vigabatrin-treated animals. Taurine levels were 67% lower in vigabatrin-treated animals than in control animals. Taurine supplementation reduced all components of retinal lesions in both rats and mice. Among six vigabatrin-treated infants, the taurine plasma level was found to be below normal in three patients and undetectable in two patients.These results indicate that vigabatrin generates a taurine deficiency responsible for its retinal phototoxicity. Future studies will investigate whether cotreatment with taurine and vigabatrin can limit epileptic seizures without inducing the constriction of the visual field. Patients taking vigabatrin could gain immediate benefit from reduced light exposures and dietetic advice on taurine-rich foods.

In patients affected by Creutzfeldt-Jakob disease and in animals affected by transmissible spongiform encephalopathies, retinal functions are altered, and major spongiform changes are observed in the outer plexiform layer where photoreceptors have their synaptic terminals. In the present study, the prion protein PrP(c) was found to form aggregates in rod photoreceptor terminals from both rat and human retina, whereas no labeling was observed in cone photoreceptors. Discrete staining was also detected in the inner plexiform layer where the prion protein was located at human amacrine cell synapses. In mixed porcine retinal cell cultures, the PrP106-126 prion peptide triggered a 61% rod photoreceptor cell loss by apoptosis as indicated by terminal deoxynucleotidyl transferase dUTP nick-end labeling, whereas cone photoreceptors were not affected. Amacrine cells were also reduced by 47% in contrast to ganglion cells. Although this cell loss was associated with a 5.5-fold increase in microglial cells, the strict correlation between the PrP(c) prion protein expression and the peptide toxicity suggested that this toxicity did not rely on the release of a toxic compound by glial cells. These results provide new insights into the retinal pathophysiology of prion diseases and illustrate advantages of adult retinal cell cultures to investigate prion pathogenic mechanisms.

Very early neuroglial changes have been observed to precede major vascular changes in the retina of diabetic patients and animal models. We investigated the sequence of these neuroglial changes further, in mice with alloxan-induced diabetes. Diabetes was induced by a single injection of Alloxan into C57/Bl6 mice, which subsequently received daily insulin injections. Diabetic and control animals were weighed and their blood glucose levels were determined weekly. Electroretinographic recordings and scanner laser ophthalmoscope (SLO) examinations were carried out 15 days, one month and three months after the onset of diabetes. Diabetes induction was confirmed by the presence of glucose in the urine, a tripling of blood glucose level, weight loss and an increase in glycated haemoglobin levels. Three months after diabetes onset, the electroretinogram b/a wave amplitude ratio was decreased at the highest light intensities and oscillatory potentials were delayed. The retinal fundus and vessels remained unchanged. No cell apoptosis was detected in vertical and horizontal sections of the retina by TUNEL or immunocytochemistry for the active caspase 3. No increase in GFAP-immunostaining indicative of a glial reaction was observed in Müller glial cells. By contrast, changes in the morphology of microglial cells were observed, with marked shortening of the dendrites. Thus, the microglial reaction occurs very early in progression to diabetic retinopathy, at about the same time as early electroretinographic modifications. The absence of apoptotic cells, contrasting with previous results in mice with streptozotocin-induced diabetes, is consistent with insulin neuroprotection.

Summary Aims After an episode of acute pancreatitis, there is usually no sequelae; nevertheless cases of ductal stenosis have been reported. The aim of our study was to evaluate the frequency of pancreatic duct lesions after acute pancreatitis complicated by pseudocyst. Patients and methods Between 1983 and 2004, 67 patients were admitted for severe acute pancreatitis. Out of these 67 patients, 36 patients were excluded because of chronic pancreatitis (N=12), intraductal papillary mucinous tumors of the pancreas (N=3), carcinoma (N=2), cystadenoma (N=3), alcohol consumption > 40 g/d (N=6), post-traumatic acute pancreatitis (N=3), and a follow-up less than 12 months (N=7). Results A stenosis of the main pancreatic duct was observed in 52% (16/31) of patients. This stenosis was isolated in 100% of cases, complete for 69% of them (11/16) and associated with upstream dilatation in 69% of cases (11/16). Although the pseudocyst was located in the body of the pancreas in 7/31 cases (48%), the stenosis was located in the head in 9/16 cases (56%). The predictive criteria of pancreatic duct lesions were complications associated with pseudocyst: extra-luminal compression (P=0.01), and vascular thrombosis (P=0.02). Conclusion After an episode of acute pancreatitis complicated by pseudocyst, pancreatic duct stenosis is observed in 52% of the cases. These results show that complete resolution of pancreatic abnormalities after acute pancreatitis is not achieved systematically.

Central nervous system neurons have traditionally been thought to express exclusively membrane transporters and/or vesicular transporters for their transmitter. Three vesicular glutamate transporters have recently been cloned: BNPI/VGLUT1 (a brain-specific sodium-dependent inorganic phosphate (Pi) transporter), and its homologs DNPI/VGLUT2 (differentiation-associated sodium-dependent Pi transporter) and VGLUT3. We investigated the subcellular distributions of these three vesicular transporters in rat and human retina. VGLUT1 was present in the outer and inner plexiform layers (OPL and IPL), as shown by punctate staining in both human and rat retina. In the OPL, it was colocalized with synaptophysin, consistent with its expression in glutamatergic photoreceptor terminals, and it was present in PKC-alpha-labeled glutamatergic bipolar cell terminals in the IPL. By contrast, VGLUT2 was present in horizontal cells and ganglion cells in rat and human retina. In human retina, VGLUT2 was also found in some amacrine cells, including GAD-immunopositive amacrine cells. VGLUT3 was present in glycine-releasing amacrine cells in rat retina but was restricted to a few ganglion cells in human retina. The distribution of VGLUT1 in excitatory synaptic terminal was consistent with its involvement in glutamate release at excitatory synapses, whereas the cellular distributions of VGLUT2 and VGLUT3 suggested that these molecules may be involved in functions other than glutamate release, such as glutamate storage for GABA synthesis in non-glutamatergic neurons.

International audience; In different animal models, photoreceptor degeneration was correlated to an abnormal increase in cGMP concentration. The cGMP-induced photoreceptor toxicity was demonstrated by applying the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine on retinal explants. To assess the role of cGMP-gated channels in this cGMP toxicity, the Ca(2+) channel blockers verapamil and L- and D-diltiazem, which block cGMP-gated channels with different efficacies, were applied to in vitro animal models of photoreceptor degeneration. These models included: (i) adult rat retinal explants incubated with zaprinast, a more specific inhibitor of the rod phosphodiesterase than 3-isobutyl-1-methylxanthine and (ii) rd mouse retinal explants. Photoreceptor apoptosis was assessed by terminal dUTP nick end labelling and caspase 3 activation. Effects of the blockers on the synaptic rod Ca(2+) channels were measured by patch-clamp recording. In the zaprinast-induced photoreceptor degeneration model, both diltiazem isomers rescued photoreceptors whereas verapamil had no influence. Their neuroprotective efficacy was correlated to their inhibition of cGMP-gated channels (l-diltiazem>d-diltiazem>verapamil=0). In contrast, all three Ca(2+) channel blockers suppressed rod Ca(2+) channel currents similarly. This suppression of the currents by the diltiazem isomers was very weak (16.5%) at the neuroprotective concentration (10 microm). In rd retinal explants, both diltiazem isomers also slowed down rod degeneration in contrast to verapamil. L-diltiazem exhibited this effect at concentrations ranging from 1 to 20 microm. This study further supports the photoreceptor neuroprotection by diltiazem particularly in the rd mouse retina, whereas the absence of neuroprotection by verapamil further suggests the role of cGMP-gated channel activation in the induction of photoreceptor degeneration.

Summary Pancreatic ductal carcinomas are thought to arise from precursor ductal lesions called pancreatic intra-epithelial neoplasias or PanINs. We report the case of a woman suffering from idiopathic chronic pancreatitis associated with PanINs lesions who developed six years later an invasive ductal carcinoma. Immunohistochemistry for p53, HER-2/ neu and genetic analysis of K-ras oncogene were performed at different stages of disease and revealed that the PanINs and the carcinoma did not express p53 and HER-2/ neu gene products whereas a K-ras mutation was present at the carcinoma stage. The relationship between cancer and chronic pancreatitis and the main difficulties concerning the early diagnostic of pancreatic cancer are discussed.

Brain-derived neurotrophic factor (BDNF) has been implicated in stimulating retinal ganglion cell (RGC) survival and axonal regeneration in rodent animal models in vivo and in vitro, but very little data are available on neurotrophin effects in higher mammals. We hence analysed BDNF signalling in primary cultures of adult pig RGC. As detected by immunohistochemistry, HPLC analysis and RT-PCR, BDNF protein and mRNA were present within pig retina in vivo and in vitro, where it may be involved in baseline RGC neuritogenesis. Initial dose-response studies established optimal effects were induced by 20 ng/ml BDNF, leading to an approximately threefold increase in neurite length. We analysed the respective contributions of phosphatidyl inositol 3 kinase (PI3K) and mitogen activated protein kinase (MAPK) cascades to BDNF-induced neurite regeneration. Addition of either the PI3K inhibitor wortmannin or the MAPK inhibitor U0126 blocked 50-100% BDNF-induced neurite elongation; U0126 also significantly reduced neurite regeneration below untreated control levels. The trk receptor inhibitor K252a had no observable effect on neurite regeneration or morphology. These data hence demonstrate that BDNF is a potent stimulator of neurite growth in RGC prepared from an adult large mammal retina, and that at least two signalling pathways are causally involved. BDNF-based therapy may be of potential use in treating RGC degeneration in humans.

The expression and potential roles of fibroblast growth factors (FGF) and their cognate FGF receptors (FGFR) in adult mammalian retinal ganglion cells (RGC) are poorly known. We show that FGFR-3 and FGFR-4 are especially pronounced on RGC and amacrine cell bodies in adult pig inner retinae both in vivo and in vitro. Western blotting revealed distinct profiles for each receptor. Expression of each FGFR and effects of the preferred ligand for FGFR-3, FGF9, upon RGC survival and neurite outgrowth were examined in primary retinal cell cultures: whereas there was no stimulation of neuritogenesis, RGC survival was promoted in a dose-dependent manner (ED(50) approximately 500 pg/ml, mean maximal increase of 60%) and could be completely blocked by addition of FGF9 neutralising antibody. Experiments with three additional FGF (FGF1, FGF2, and FGF4) showed no stimulation of RGC survival above control levels. Taken together, these data suggest that the ligand-receptor couple FGF9-FGFR-3 may function to promote survival of adult mammalian RGC, and their application might be beneficial in retinal degenerative diseases such as glaucoma.

Basic fibroblast growth factor (FGF2) stimulates photoreceptor survival in vivo and in vitro, but the molecular signaling mechanism(s) involved are unknown. Immunohistochemical and immunoblotting analyses of pure photoreceptors, inner retinal neurons, and Müller glial cells (MGC) in vitro revealed differential expression of the high affinity FGF receptors (FGFR1-4), as well as many cytoplasmic signaling intermediates known to mediate the extracellular signal-regulated kinase (ERK1/2) pathway. FGF2-induced tyrosine phosphorylation in vitro exhibited distinct profiles for each culture type, and FGF2-induced ERK1/2 activation was observed for all three preparations. Whereas U0126, a specific inhibitor of ERK kinase (MEK), completely abolished FGF2-induced ERK1/2 tyrosine phosphorylation and survival in cultured photoreceptors, persistent ERK1/2 phosphorylation was observed in cultured inner retinal cells and MGC. Furthermore U0126 treatment entirely blocked nerve growth factor-induced ERK1/2 activation in MGC, as well as FGF2-induced ERK1/2 activation in cerebral glial cells. Taken together, these data indicate that FGF2-induced ERK1/2 activation is entirely mediated by MEK within photoreceptors, which is responsible for FGF2-stimulated photoreceptor survival. In contrast, inner retina/glia possess alternative, cell type, and growth factor-specific MEK-independent ERK1/2 activation pathways. Hence signaling and biological effects elicited by FGF2 within retina are mediated by cell type-specific pathways.

Protein MAP1B was recently reported to link GABA(C) receptors to the cytoskeleton at neuronal synapses. This interaction was demonstrated in the mammalian retina, where GABA(C) receptors were thought to be exclusively expressed in bipolar cells. Our previous studies on cultured photoreceptors suggested however the presence of GABA(C) receptors in cones. To further investigate GABA(C) receptor expression in cones, we measured GABA responses in mammalian photoreceptors in situ, and we examined the distribution of the receptor and that of protein MAP1B in the mammalian outer retina. Photoreceptors were recorded from flat-mounted retinas of retinal degeneration mice at an age when the retina becomes cone-dominated after rod cell death. GABA(A) and GABA(C)-gated currents were produced only in cones but not rods. Recording freshly dissociated retinal cells from wild-type C57 mice confirmed the presence of GABA(A) and GABA(C) receptors in cones. Immunohistochemical labeling of mouse and rat retinal sections localized GABA(C) receptors to cone terminals that were identified by peanut agglutinin lectin staining. As expected from previous studies on bipolar cells, the punctate immunostaining was not restricted to cone terminals in the outer plexiform layer. MAP1B immunolabeling was obtained in rat and pig retinas and was similarly found in cone terminals identified by the peanut agglutinin lectin staining. These results provide physiological and histological evidence that cones receive a GABA feedback in the mammalian retina and are consistent with the notion that protein MAP1B links GABA(C) receptors to the cytoskeleton at postsynaptic sites.

OBJECTIVE: Several cases of pancreatitis have been described during the course of Crohn’s disease (CD) or ulcerative colitis (UC), but many of them were related to either biliary lithiasis or drug intake. We tried to evaluate the clinical and morphological features of so-called idiopathic pancreatitis associated with inflammatory bowel disease and to define their pathological characteristics. METHODS: Chronic idiopathic pancreatitis was diagnosed on the basis of abnormal pancreatograms suggestive of chronic pancreatitis associated with or without impaired exocrine pancreatic function, or pathological examination in patients undergoing pancreatic resection. We found 6 patients presenting with features of chronic idiopathic pancreatitis and UC and 2 patients with CD seen between 1981 and 1996 in three hospital centers of the south of France. A review of the literature has identified 6 cases of pancreatitis associated with UC and 14 cases of pancreatitis associated with CD based on the above criteria. RESULTS: Hyperamylasemia was not a sensitive test since it was present in 44% and 64% of patients with UC or CD. In UC, pancreatitis was a prior manifestation in 58% of patients. In contrast, the pancreatitis appeared after the onset of CD in 56% of the cases. In patients with UC, pancreatitis were associated with severe disease revealed by pancolitis (42%) and subsequent surgery. Bile duct involvement was more frequent in patients with UC than with CD (58% vs 12%) mostly in the absence of sclerosing cholangitis (16% vs 6%). Weight loss and pancreatic duct stenosis were also more frequent in UC than in CD (41% vs 12% and 50% vs 23%, respectively). Pathological specimens were analyzed in 5 patients and demonstrated the presence of inter- and intralobular fibrosis with marked acinar regression in 3 and the presence of granulomas in 2 patients, both with CD. CONCLUSIONS: Pancreatitis is a rare extraintestinal manifestation of inflammatory bowel disease. Chronic pancreatitis associated with UC differs from that observed in CD by the presence of more frequent bile duct involvement, weight loss, and pancreatic duct stenosis, possibly giving a pseudo-tumor pattern.

Objective To evaluate prospectively the efficacy and safety of autologous platelet concentrate (APC) as an adjuvant in surgery for idiopathic macular hole. Design Multicenter, double-masked, randomized clinical trial. Setting Four university-based ophthalmology clinics. Participants One hundred ten patients with stage 3 or 4 idiopathic full-thickness macular holes of less than 3 years' duration were randomized (53 eyes to the platelet group and 57 eyes to the control group). Interventions Standardized macular hole surgery versus surgery combined with injection of an APC. In all cases, the procedure consisted of three-port pars plana vitrectomy, posterior hyaloid separation, and nonexpansile fluid-gas exchange. After the fluid-gas exchange, patients were randomized to receive either injection of an APC or no adjunctive treatment. After surgery, patients were positioned face down for 12 days. Platelet counts showed that the concentrates contained a mean of 96.10 6 platelets (range, 82–102). Main outcome measures Anatomic and functional evaluations were performed at 1, 3, and 6 months after surgery in a double-masked fashion by an independent observer. The main outcome was reapposition of the edge of the macular hole 1 month after surgery. Secondary outcomes were anatomic status at 3 and 6 months, changes in Early Treatment Diabetic Retinopathy Study score, and complications. Results One month after surgery, the anatomic success rate in the platelet group was 52 of 53 (98%; 95% confidence interval, 0.90–1.00) versus 47 of 57 (82%; 95% confidence interval, 0.70–0.91) in the control group ( P = 0.009, Fisher's exact test; relative risk, 0.11; 95% confidence interval, 0.01–0.81). Visual acuity was not significantly different between the two groups at any timepoint. There were no complications specifically attributable to the platelet injection. Conclusion Injection of APC improved significantly the anatomic success rate of surgery for idiopathic macular holes of less than 3 years' duration, but postoperative visual acuity of the platelet group was not statistically different from the control group.

Glutamate is the most abundant excitatory amino acid in the central nervous system. It has also been described as a potent toxin when present in high concentrations because excessive stimulation of its receptors leads to neuronal death. Glial influence on neuronal survival has already been shown in the central nervous system, but the mechanisms underlying glial neuroprotection are only partly known. When cells isolated from newborn rat retina were maintained in culture as enriched neuronal populations, 80% of the cells were destroyed by application of excitotoxic concentrations of glutamate. Massive neuronal death was also observed in newborn retinal cultures containing large numbers of glia, or when neurons were seeded onto feeder layers of purified cells prepared from immature (postnatal 8 day) rat retina. When newborn retinal neurons were seeded onto feeder layers of purified glial cells prepared from adult retinas, application of excitotoxic amino acids no longer led to neuronal death. Furthermore, neuronal death was not observed in mixed neuron/glial cultures prepared from adult retina. However, in all cases (newborn and adult) application of kainate led to amacrine cell-specific death. Activity of glutamine synthetase, a key glial enzyme involved in glutamate detoxification, was assayed in these cultures in the presence or absence of exogenous glutamate. Whereas pure glial cultures alone (from young or adult retina) showed low activity that was not stimulated by glutamate addition, mixed or co-cultured neurons and adult glia exhibited up to threefold higher levels of activity following glutamate treatment. These data indicate that two conditions must be satisfied to observe glial neuroprotection: maturation of glutamine synthetase expression, and neuron-glial signalling through glutamate-elicited responses.

Glutamate, the principal retinal neurotransmitter, can also act as a toxin when present in excessive concentrations as may occur in pathologies such as retinal ischemia or more generally in cerebral neuronal degenerative disease. As glial cells play pivotal roles in transfer of blood-borne molecules and in glutamate clearance, we investigated the effects of the excitatory amino acids glutamic and kainic acid on different in vitro preparations of retinal Müller glial cells. Glial viability or morphology were not influenced by excitatory amino acid exposure in either pure glial cultures or in monolayer cultures of mixed neonatal neurons and glia, whereas kainic acid specifically lysed amacrine cells in mixed or pure neuronal cultures. When retinal fragments were pre-incubated in excitatory amino acids prior to dissociation and seeding into culture, under these conditions Müller glial cells exhibited a dramatic loss of their normal epithelioid form to a retracted morphology. However, glial cell viability was not compromised, and rapid restoration of epithelioid in vitro glial morphology could be achieved by addition of exogenous epidermal and basic fibroblast growth factor to the culture medium. This study demonstrates that glial cells are structurally perturbed by excitotoxic conditions and that such effects are dependent on normal glial-neuronal interactions.

Polypeptide growth factors and gangliosides can both be considered as trophic agents involved in almost all stages of neural cell development, differentiation, survival, and pathology. In most cases their physiological roles are still not clear due to the considerable complexity in their regulation. Several growth factors [e.g., basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF)] and one species of ganglioside (GM1) have been shown to exert interactions with each other and also to exhibit neuroprotective effects against retinal ischemia in vivo and cerebral excitotoxicity in vitro. Different experimental models are used to investigate their relevance to ischemic and excitotoxic conditions in the retina, and it is shown that (1) both bFGF and EGF show very effective neuroprotection for rat retinal neurones exposed to toxic levels of glutamate or its nonphysiological agonist kainate in vitro; (2) GM1 (10−5 M) used under the same conditions does not afford protection; (3) retinal glial cells also suffer morphological perturbations following glutamate or kainate treatment, but this effect is dependent on neuron-glial interactions, indicating the existence of intermediate neuron-derived messenger molecules; (4) these glial changes can be corrected by posttreatment with either bFGF or EGF in vitro; (5) using an in vivo animal model involving anterior chamber pressure-induced ischemia in adult rats, it is shown that either pretreatment by intraperitoneal injection of GM1, or posttreatment by intraocular injection of the same ganglioside, reduces significantly histological damage to inner nuclear regions; and (6) in cultured retinal Muller glial cells the existence of molecular and metabolic interactions between both types of trophic factors is demonstrated. Hence both these groups of trophic molecules show interesting features for retinal ischemic treatment.

1. At least two different groups of molecules can be considered neurotrophic factors because they exert a variety of effects upon neural cells. The first consists of the numerous families of polypeptide growth factors known to take part in almost all stages of neural cell growth and functioning, including development, differentiation, survival and pathology. The second group also is characterized by extensive complexity of multiple forms, and consists of the sialic acid-containing glycosphingolipids or gangliosides. These molecules also take part in the transfer of information from the extracellular milieu to the cell interior, and, similarly to growth factors, are participants in such aspects as development, differentiation and functioning. 2. In this short overview, we consider the existing data on the neuroprotective effects of growth factors [e.g., basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) and brain-derived neurotrophic factor] and one species of ganglioside (GM1) against retinal ischemia in vivo and cerebral excitotoxicity in vitro. 3. We used three different experimental models to investigate their relevance to ischemic and excitotoxic conditions in the retina and have shown that: (a) both bFGF and EGF show highly effective neuroprotection for rat retinal neurons exposed to toxic levels of glutamate or its nonphysiological agonist kainate in vitro (b) retinal glial cells suffer morphological perturbations after glutamate or kainate treatment, and this effect depends on neuron-glial interactions; (c) these glial changes can also be corrected by posttreatment with either bFGF or EGF in vitro; (d) with the use of an in vivo animal model involving anterior chamber pressure-induced ischemia in adult rats, either pretreatment by intraperitoneal injection of GM1 or posttreatment by intraocular injection of the same ganglioside significantly reduces histological damage to inner nuclear regions. 4. Hence both groups of trophic molecules show interesting features for retinal ischemic treatment.

Objectives: To describe the clinical and radiological patterns of chronic calcifying pancreatitis (CCP) associated with pancreas divisum. Design: Case-control study. Methods: Pancreas divisum was diagnosed in 20 out of 411 patients presenting with CCP between 1985 and 1994 (group I). They were matched for age and sex with 20 patients presenting with CCP but without pancreas divisum (group II). The cause of CCP was presumed to be mainly chronic alcohol use, as 18 patients in each group had heavy alcohol consumption. Results: The age at onset of the disease was comparable in the two groups (mean 40.8 compared with 42.4 years, NS), and consumption of alcohol and tobacco did not differ. Pancreatic calcified calculi were seen on plain films of the abdomen in eight patients from group I and in 14 patients from group II (P=0.05). Loss of weight (>5 kg), diabetes, portal hypertension and the rate of complications of chronic pancreatitis were not significantly different in the two groups. The frequency of attacks of acute pancreatitis was similar (mean 0.9 compared with 1.2 per year, range 0.2–6.0 per year, NS). The occurrence of pseudocysts did not differ (11 compared with 15, NS). Pancreatograms were categorized using the Cambridge classification. No differences could be demonstrated between the two groups (χ2, P=0.15). In group I, pancreatographic abnormalities were located only in the ventral segment of the pancreas in three patients, only in the dorsal segment of the pancreas in nine patients and in the whole pancreas in six patients. In two patients, the ventral duct could not be demonstrated. Conclusion: We conclude that pancreas divisum does not modify the natural course of CCP. In about one-half of cases, pancreatographic abnormalities may be segmental.

Background: Endoscopic therapy of pancreatic pseudocysts has been reported mainly in small series. Methods : The results of endoscopic transpapillary cyst drainage (ETCD) were evaluated prospectively in 30 patients with pancreatic pseudocysts. Results: There were 24 men and 6 women with an average age of 45 years (SD 16). Twenty-eight had chronic pancreatitis (25 with alcoholic pancreatitis). Transpapillary cystopancreatic stents, with the tip into the cyst cavity, were inserted in 12 patients. Pancreatic stents with the tip as close as possible from the cyst cavity were inserted in the remaining 18 patients. Ten patients underwent an additional endoscopic cystenterostomy. The average duration of stenting was 4.4 months (range 15 days to 12 months). Patients were followed up for 15 months (range 2 to 60 months). All pseudocysts communicated with the pancreatic ductal system. The size of the pseudocysts ranged from 15 to 120 mm (average 50 mm). Pseudocysts were mainly located in the head of the pancreas (17 cases). Four minor complications occurred. There were no deaths. Twenty-six patients had pseudocyst resolution by ETCD, but 7 ultimately required surgery, 3 for early recurrence and 4 for failure of initial therapy. Conclusion: ETCD appears to be a safe and efficient modality for the drainage of pancreatic pseudocysts communicating with the pancreatic ductal system. (Gastrointest Endosc 1995;42:208-13.)

International audience; Glaucoma, the most common cause of irreversible blindness, is a neuropathy commonly initiated by pathological ocular hypertension due to unknown mechanisms of trabecular meshwork degeneration. Current antiglaucoma therapy does not target the causal trabecular pathology, which may explain why treatment failure is often observed. Here we show that the chemokine CXCL12, its truncated form SDF-1(5-67), and the receptors CXCR4 and CXCR3 are expressed in human glaucomatous trabecular tissue and a human trabecular cell line. SDF-1(5-67) is produced under the control of matrix metallo-proteinases, TNF-α, and TGF-β2, factors known to be involved in glaucoma. CXCL12 protects in vitro trabecular cells from apoptotic death via CXCR4 whereas SDF-1(5-67) induces apoptosis through CXCR3 and caspase activation. Ocular administration of SDF-1(5-67) in the rat increases intraocular pressure. In contrast, administration of a selective CXCR3 antagonist in a rat model of ocular hypertension decreases intraocular pressure, prevents retinal neurodegeneration, and preserves visual function. The protective effect of CXCR3 antagonism is related to restoration of the trabecular function. These data demonstrate that proteolytic cleavage of CXCL12 is involved in trabecular pathophysiology, and that local administration of a selective CXCR3 antagonist may be a beneficial therapeutic strategy for treating ocular hypertension and subsequent retinal degeneration.

International audience; Dystrophin, the protein defective in Duchenne muscular dystrophy (DMD), plays a critical role in the formation and maintenance of the neuromuscular junction. In addition to dystrophin, activation of internal promoters of the DMD gene leads to the production of several short products. Among these, Dp71, which consists of the C-terminal domain of dystrophin, is the most abundant product of the gene in non-muscle tissues and brain. In this report, we compare the temporal and regional expression patterns of dystrophin and Dp71 at different stages of embryonic development and during retinal differentiation in zebrafish. The Dp71 transcripts are the earliest to be expressed at 9-10 h post-fertilization (hpf) in the axial mesoderm. As development proceeds, intense Dp71 staining is observed in the notochord, the developing brain, the marginal regions of the somites and the eye primordium. At the completion of retinal differentiation, Dp71 is expressed in the ganglion and inner nuclear layers. Transcripts encoding dystrophin have a slightly later onset of expression, 13-14 hpf, and remain restricted to the transverse myosepta through all the developmental stages examined. The complementary patterns of expression of dystrophin and Dp71 suggest that these two proteins exert different functions during embryonic development in zebrafish.

International audience; The dystrophin-associated proteins (DAPs) complex consisting of dystroglycan, syntrophin, dystrobrevin, and sarcoglycans in muscle cells is associated either with dystrophin or its homolog utrophin. In rat retina, a similar complex was found associated with dystrophin-Dp71 that serves as an anchor for the inwardly rectifying potassium channel Kir4.1 and the aqueous pore, aquaporin-4 (AQP4). Here, using immunofluorescence imaging of isolated retinal M?r glial cells and co-immunoprecipitation experiments performed on an enriched M?r glial cells end-feet fraction, we investigated the effect of Dp71 deletion on the composition, anchoring, and membrane localization of the DAPs-Kir4.1 and/or -AQP4 complex. Two distinct complexes were identified in the end-feet fraction associated either with Dp71 or with utrophin. Upon Dp71 deletion, the corresponding DAPs complex was disrupted and a compensating utrophin upregulation was observed, accompanied by diffuse overall staining of Kir4.1 along the M?r glial cells and redistribution of the K(+) conductance. Dp71 deficiency was also associated with a marked reduction of AQP4 and beta-dystroglycan expression. Furthermore, it was observed that the Dp71-DAPs dependent complex could be, at least partially, associated with a specific membrane fraction. These results demonstrate that Dp71 has a central role in the molecular scaffold responsible for anchoring AQP4 and Kir4.1 in M?r cell end-feet membranes. They also show that despite its close relationship to the dystrophin proteins and its correlated upregulation, utrophin is only partially compensating for the absence of Dp71 in M?r glial cells. (c) 2008 Wiley-Liss, Inc.

Vigabatrin was a major drug in the treatment of epilepsy until the discovery that it was associated with an irreversible constriction of the visual field. Nevertheless, the drug is still prescribed for infantile spasms and refractory epilepsy. Disorganization of the photoreceptor nuclear layer and cone photoreceptor damage have been described in albino rats. To investigate the vigabatrin-elicited retinal toxicity further, we examined the retinal tissue of albino mice treated with two vigabatrin doses. The higher dose did not always cause the photoreceptor layer disorganization after 1 month of treatment. However, it triggered a massive synaptic plasticity in retinal areas showing a normal layering of the retina. This plasticity was shown by the withdrawal of rod but not cone photoreceptor terminals from the outer plexiform layers towards their cell bodies. Furthermore, both rod bipolar cells and horizontal cells exhibited dendritic sprouting into the photoreceptor nuclear layer. Withdrawing rod photoreceptors appeared to form ectopic contacts with growing postsynaptic dendrites. Indeed, contacts between rods and bipolar cells, and between bipolar cells and horizontal cells were observed deep inside the outer nuclear layer. This neuronal plasticity is highly suggestive of an impaired glutamate release by photoreceptors because similar observations have been reported in different genetically modified mice with deficient synaptic transmission. Such a synaptic deficit is consistent with the decrease in glutamate concentration induced by vigabatrin. This description of the neuronal plasticity associated with vigabatrin provides new insights into its retinal toxicity in epileptic patients.

International audience; PURPOSE: In retinal diseases characterized by photoreceptor degeneration, the main cause of clinically significant vision loss is cone, rather than rod, loss. In the present study, a technique was designed to purify cones to make it possible to screen for neuroprotective molecules. METHODS: A suspension of porcine retinal cells was incubated on coverslips coated with the peanut agglutinin (PNA) lectin, which selectively binds to cones. Cones were identified and quantified by using an antibody specific for cone arrestin. Their identity and viability were also assessed by single-cell RT-PCR and patch-clamp recording. RESULTS: This panning method provided a population of cones that was 80% to 92% pure, depending on the counting strategy used. The panned cells contained both short (S)- and medium/long (M/L)-wavelength opsin cones. The panned retinal cells exhibited the physiological signature of cone photoreceptors and single-cell reverse transcriptase-polymerase chain reaction (RT-PCR) showed that they expressed the cone arrestin mRNA. Most (69%) cone photoreceptors produced neurites and survived for up to 7 days when cultured in a glia-conditioned medium, whereas very few (4%) survived after 7 days in the control medium. CONCLUSIONS: This PNA-lectin-panning method can provide highly pure and viable mammalian cones, the survival of which can be prolonged by glia-conditioned medium. Because PNA lectin binds to cone photoreceptors from various species in both normal and pathologic conditions, this technique should enable the screening of neuroprotective molecules like those released by glial cells and enable the physiological, genomic, and proteomic characterization of cones.

International audience; PURPOSE: Cell death is often related to an abnormal increase in Ca(2+) flux. In the retina, Ca(2+) channels are mainly from the L-type that do not inactivate with time. Under excitotoxic and ischemic conditions, their continuous activation may therefore contribute significantly to the lethal Ca(2+) influx. To assess this hypothesis, the Ca(2+) channel blocker, diltiazem, was applied in excitotoxic and ischemic conditions. METHODS: To induce excitotoxicity, retinal cell cultures from newborn rats were incubated with glutamate. The toxicity of glutamate was quantified by neuronal immunostaining with an antibody directed against the neuron specific enolase. Glutamate receptor function in vitro was assessed in pig retinal cell cultures by patch clamp recording. Retinal ischemia was induced by raising the intraocular pressure in adult rats. Retinal cell loss was quantified on retinal sections by measuring nuclear cell densities. RESULTS: In retinal cell culture, glutamate application induced a major cell loss. This cell loss was attributed to glutamate excitotoxicity because glutamate receptor blockers like MK-801 and CNQX increased significantly neuronal survival. MK-801 and CNQX, which block NMDA and AMPA/Kainate receptors, respectively, had additive effects. Expression of AMPA/Kainate glutamate receptors in mixed adult retinal cell cultures was attested by patch clamp recording. In newborn rat retinal culture, glutamate excitotoxicity was significantly reduced by addition of the L-type Ca(2+) channel blocker, diltiazem. In in vivo experiments, the increase in ocular pressure induced a decrease in cell number in the inner nuclear and ganglion cell layers. When animals received diltiazem injections, the ischemic treatment induced a less severe reduction in retinal cells; this neuroprotection was statistically significant in the ganglion cell layer. CONCLUSION: These results are consistent with previous studies suggesting that Ca(2+) channel activation contributes to retinal cell death following either glutamate excitotoxicity or retinal ischemia. Under both conditions, the L-type Ca(2+) channel blocker, diltiazem, can limit cell death. These results extend the potential application of diltiazem in retinal neuroprotection to retinal pathologies involving glutamate excitotoxicity and ischemia.

Vitamin A (retinol) actions in eye development are mediated by retinoic acid receptors (RARs and RXRs). Using the Cre/loxP system, we have selectively ablated RXR alpha in the retinal pigment epithelium (RPE), a cell monolayer critically involved in visual retinoid renewal and phagocytosis of photoreceptor outer segments. In the mutant (RXR alpha (rpe-/-)) mice, RPE cells are morphologically and functionally abnormal and display decreased expression of proteins involved in the visual retinoid cycle, namely RPE65, CRALBP, and RGR. RXR alpha (rpe-/-) mice also show alterations of photoreceptor cells including: 1) decrease in their number; 2) outer segment shortening and disorganization, and 3) reduced light responses in electroretinograms. These results indicate that RXR alpha is required for normal maturation of the RPE, which is known to play essential roles in photoreceptor cell function and survival, and point to a possible involvement of RXR alpha signaling pathways in the RPE in human retinal diseases.

PURPOSE. Ultrahigh-resolution, full-field optical coherence tomography (OCT), which uses a white light source, allows bidimensional, noninvasive tomographic imaging without scanning. The goal of the present study was to apply full-field OCT to ocular tissue imaging in an attempt to explore the capabilities of the technique. METHODS. This full-field OCT system uses a Linnik-type interferometer with a tungsten-halogen source. The spatial resolution is 0.9 0.7 m (transverse axial). Unstained tissue samples (cornea, lens, retina, choroid, and sclera) and whole, unfixed eyes of rat, mouse, and pig were examined under immersion. A charge-coupled device (CCD) camera recorded a pair of interferometric images that were combined to display en face (i.e., in the x-y plane) tomographic images in real time. The acquisition time per tomographic image, which includes summation of 10 raw images, was on the order of 1 s. Postprocessing allows volumetric navigation through the image stack as well as three-dimensional (3D) imaging. RESULTS. Cellular-level resolution was achieved in isolated tissue samples. En face (x-y) images revealed corneal epithelial and stromal cells, lens fibers, nerve fibers, major vessels, and retinal pigment epithelial cells. In x-z reconstructions, cellular layers within the cornea and retina and arterioles and venules were clearly defined. Transscleral retinal imaging was achieved in albino animals. CONCLUSIONS. Ultrahigh-resolution, full-field OCT allows cellular-level imaging of unstained ocular tissues with high penetration depth. Although the current system is unsuitable for clinical use, this simple technique has potential for in vivo ocular examination, for which a new system is currently under development. (Invest Ophthalmol Vis Sci. 2004;45: 4126‐4131) DOI:10.1167/iovs.04-0584

The abnormal retinal neurotransmission observed in Duchenne muscular dystrophy (DMD) patients and in some genotypes of mice lacking dystrophin has been attributed to altered expression of short products of the dystrophin gene. We have investigated the potential role of Dp71, the most abundant C-terminal dystrophin gene product, in retinal electrophysiology. Comparison of the scotopic electroretinograms (ERG) between Dp71-null mice and wild-type (wt) littermates revealed a normal ERG in Dp71-null mice with no significant changes of the b-wave amplitude and kinetics. Analysis of DMD gene products, utrophin and dystrophin-associated proteins (DAPs), showed that Dp71 and utrophin were localized around the blood vessels, in the ganglion cell layer (GCL), and the inner limiting membrane (ILM). Dp71 deficiency was accompanied by an increased level of utrophin and decreased level of beta-dystroglycan localized in the ILM, without any apparent effect on the other DAPs. Dp71 deficiency was also associated with an impaired clustering of two Muller glial cell proteins-the inwardly rectifying potassium channel Kir4.1 and the water pore aquaporin 4 (AQP4). Immunostaining of both proteins decreased around blood vessels and in the ILM of Dp71-null mice, suggesting that Dp71 plays a role in the clustering and/or stabilization of the two proteins. AQP4 and Kir4.1 may also be involved in the regulation of the ischemic process. We found that a transient ischemia resulted in a greater damage in the GCL of mice lacking Dp71 than in wt mice. This finding points at a crucial role played by Dp71 in retinal function.

PURPOSE: To define the nature and estimate the molecular weight range of soluble endogenous retinal trophic activities on cone photoreceptor survival in two models of cone degeneration. METHODS: Diffusible factors from dissociated retinal cell cultures of 8-day normal-sighted (C57BL/6J) mice were tested for cone-survival-promoting activity by two approaches and by using two independent photoreceptor degeneration models. In the first approach, mouse retinal cells were cultured on semi-permeable membranes apposed to dissociated cultures of chick embryo retina. In the second approach, conditioned medium was collected from normal mouse retinal cultures and added to embryonic chicken retina cultures or to retinal explants obtained from 5-week retinal degeneration (rd1) mice. In some experiments, conditioned medium was heated or sequentially fractionated in dialysis tubing with molecular weight cutoffs of 8, 15, and 25 kDa. The number of chicken cones and viability were determined by using morphologic criteria, colorimetric assays, and labeling with antibodies raised against visinin. Mouse cones were counted by differential double immunolabeling with antibodies against rhodopsin (rods) and arrestin (rods and cones). RESULTS: . Coculturing with normal mouse retinal cells delayed cone loss in dispersed embryonic chicken retina, by a maximum of 50% relative to the control. Conditioned medium derived from normal mouse retinas also significantly delayed cone loss in chicken cone cultures by a maximum of 1300%, compared with the control, and 40% in rd1 mouse retinal explant cultures. The survival activity in conditioned medium was destroyed by heat denaturation, and was partially retained by dialysis with a molecular weight cutoff of 25 kDa in both models. CONCLUSIONS: These strategies have identified cone-survival-stimulating activities in normal mouse retina, capable of acting across species and enhancing both structural protection and viability. Such molecules may represent candidates for clinical treatment of inherited retinal degeneration.

Huntington's disease (HD) and spinocerebellar ataxia type 7 (SCA7) belong to a group of progressive neurodegenerative diseases caused by polyglutamine (polyQ) expansions. SCA7 is the only one to display degeneration in the retina, a tissue usually spared in HD. We previously described a SCA7 transgenic retinal model expressing mutant full length ataxin-7 in rod photoreceptors. These mice develop a severe and characteristic retinopathy. We show here that R6 transgenic mice, which reproduce many features of HD, express mutant huntingtin in the retina leading to strong vision deficiencies and retinal dystrophy. These two different polyQ mouse models exhibit comparable early and progressive retinal degeneration and dysfunction. These abnormalities are reminiscent of other retinal degeneration phenotypes (in particular rd7/rd7 mice) where photoreceptor cell loss occurs. Retinopathy in R6 and R7E models can be monitored in living mice by ERG and fundus examination, which can facilitate in vivo evaluation of therapeutic agents in polyQ disorders.

Dystrophin glycoprotein complex (DGC) assembly and function require mediation by dystrophin in skeletal muscle. The existence of such complexes and the correlation with DMD phenotypes are not yet established in the central nervous system. Here we have studied the expression of DMD gene mRNAs and proteins in retina from C57BL/6 and mdx(3Cv) mouse strains. Then we have comparatively investigated the localization of dystrophin and dystrophin-associated proteins (DAPs) in both strains to analyze the repercussion of the mdx(3Cv) mutation on the retinal distributions of alpha/beta-dystroglycan, alpha1-syntrophin, alpha-dystrobrevin, and delta/gamma-sarcoglycan. Results showed that DMD gene product deficiency affects the expression of dystroglycan assembly exclusively at the outer plexiform layer without an apparent effect on the other DAPs. We conclude that the localization of members of the DGC could be independent of the presence of the DMD gene products and/or utrophin.

GABA is the major inhibitory neurotransmitter in the brain as well as in the vertebrate retina. Its actions on bicuculline-sensitive ionotropic GABAA receptors and metabotropic GABAB receptors have been well documented. GABAC receptors, a third receptor type less common in the CNS (Johnston, 1996), have recently drawn much attention to the retina because the GABAC receptor ρ-subunits were cloned from a retinal library (Cutting et al. 1991), and were expressed in oocytes from the corresponding cDNA (Shimada et al. 1992) or after injecting bovine retinal mRNA (Polenzani et al. 1991). GABAC receptors were subsequently recorded from retinal neurons: bipolar cells (rat: Feigenspan et al. 1993; salamander: Lukasiewicz et al. 1994; fish: Matthews et al. 1994), horizontal cells (fish: Qian & Dowling, 1993) and ganglion cells (salamander: Zhang & Slaughter, 1995). Although these receptors gate Cl− channels similarly to GABAA receptors, they have distinct pharmacologies, GABA sensitivities and modulations (Bormann & Feigenspan, 1995; Johnston, 1996). Their pharmacological profile includes a lack of bicuculline sensitivity and their ρ-subunits exhibit only 30–38 % homology with those of GABAA receptors (Cutting et al. 1991). In mammals, GABAC receptor-gated currents were not recorded in horizontal cells (Blanco et al. 1996). Their presence in rat bipolar cells was first detected in cultured neonatal cells (Feigenspan et al. 1993), and confirmed with freshly dissociated adult cells (Feigenspan & Bormann, 1994) and retinal slices (Euler et al. 1996). In situ hybridization on rat retinal sections and isolated cells confirmed the expression of ρ1- and ρ2-subunits in bipolar cells (Enz et al. 1995). Furthermore, immunostaining for ρ-subunits was mostly located in the subdivision of the outer and inner plexiform layers containing bipolar cell processes (Enz et al. 1996; Koulen et al. 1997). No information is yet available on the GABA sensitivity of mammalian photoreceptors despite the major role described for GABA in the feedback signal from horizontal cell to cone photoreceptors in lower vertebrates (for review see Piccolino, 1995). This mechanism, which generates the surround component of the cone complex antagonistic centre- surround receptive field, is thought to be mediated by GABAA receptors found at cone terminals in turtle (Kaneko & Tachibana, 1986). This hypothesis is only supported in the mammalian retina by GABAA receptor immunolabelling, irregularly found in cone pedicles (Hughes et al. 1989, 1991). Here we provide physiological and histological evidence for the expression of GABAC receptors in adult mammalian cone photoreceptors. Physiological measurements were obtained from a new photoreceptor–glia co-culture system that we specifically developed to record photoreceptors.

Objective: Radiolucent pancreatic lithiasis (RPL) has been identified as a different entity from calcified pancreatic lithiasis. The purpose of this study is to evaluate the frequency, characteristics and evolution of RPL. Patients: Between 1983 and 1995, 278 consecutive patients who presented with pancreatic lithiasis were studied. Forty-four patients had RPL (15.8%): 27 had pure radiolucent stones (PRS) (group 1), 5 had pure radiolucent stones combined with evenly calcified stones (ECS) (group 2), 2 had target calculi (TC) (radiolucent core with calcified shell) (group 3), 10 had TC combined with ECS (group 4). Results: Among the 27 patients with PRS, there were 19 males with a mean age of 41 years. PRS were mainly located in the head of the pancreas with a mean diameter of 5 mm (range 3-26mm). Seven patients among 27 with PRS (26%) were less than 20 years old (juvenile form) or more than 60 years old (senile form). They were characterized by no or low alcohol consumption and a high rate of attacks of acute pancreatitis. In group 1, PRS turned to more advanced calcified stages in 6/16 of patients (37%) followed in 30 to 144 months with a prior stage of TC in 2 cases. An evolution toward more calcified stages (TC or ECS) occurred in half of the patients belonging to group 2 and 4 in 36 to 84 months. Genetic disposition and alcohol consumption could account for the evolution toward more calcified stages. A genetic factor is suggested by a rapid evolution to evenly calcified stones in two aged children 8 and 10 years and by a high frequency of familial cases in patients belonging to groups 2 and 4 (60% and 20%) as compared to group 1 with PRS (4%). Alcohol consumption could accelerate the calcifying process since patients belonging to groups 2 and 4 had a significantly higher alcohol consumption than those with PRS (group 1). Conclusion: RPL is a heterogeneous pancreatic disease including juvenile and senile presentation which may represent about 15% of pancreatic lithiasis. Evolution towards calcified stages (PRS then TC then ECS) occurred in 37-50% of cases and could be related to a genetic factor and increased alcohol consumption.

Background: AIDS-related sclerosing cholangitis occurs in patients with advanced immunodeficiency, but ductal pancreatic alterations have not been evaluated in large series. Methods: Twenty-nine consecutive patients with a mean age of 33 years underwent ERCP for biliary work-up. Complete pancreatography was obtained in 28 patients. Serum levels of amylase were increased in 17 patients prior to ERCP. The mean duration of HIV infection was 6.1 years (range 3 to 10 years). Results: Fifteen patients (53.6%) had pancreatographic changes classified according to the Cambridge classification (stage 1, 4 cases; stage 2, 7 cases; stage 3, 4 cases). Dilatations, irregularities, short stenoses of the main pancreatic duct, and irregularities of side branches were the most frequent abnormalities. Fourteen of these 15 patients (93.3%) had cholangitis and a CD4 cell count of less than 60 per cubic millimeter. Risk factors for pancreatic damage were similar in patients with and without pancreatographic changes. Opportunistic infection occurred in 14 of 15 patients with pancreatographic changes (candida, cytomegalovirus, cryptosporidia, microsporidia, and mycobacteria). Conclusion: Abnormal pancreatographies were found in about half of the HIV-infected patients who underwent ERCP. The pancreatographic features were suggestive of chronic pancreatitis and were closely related to the presence of AIDS-related sclerosing cholangitis. (Gastrointest Endosc 1997;45:59-63.)

Usher syndrome type I (USH1) associates severecongenital deafness, vestibular dysfunction andprogressive retinitis pigmentosa leading to blindness.The gene encoding myosin VIIA is responsible forUSH1B. Mutations in the murine orthologous gene leadto the shaker-1 phenotype, which manifests cochlearand vestibular dysfunction, without any retinal defect. Toaddress this phenotypic discrepancy, the expression ofmyosin VIIA in retinal cells was analyzed in human andmouse during embryonic development and adult life. Inthe human embryo, myosin VIIA was present first in thepigment epithelium cells, and later in these cells as wellas in the photoreceptor cells. In the adult human retina,myosin VIIA was present in both cell types. In contrast,in mouse, only pigment epithelium cells expressed theprotein throughout development and adult life. MyosinVIIA was also found to be absent in the photoreceptorcells of other rodents (rat and guinea-pig), whereas thesecells expressed the protein in amphibians, avians andprimates. These observations suggest that retinitispigmentosa of USH1B results from a primary rod andcone defect. The USH1B/shaker-1 paradigm illustrates aspecies-specific cell pattern of gene expression as apossible cause for the discrepancy between phenotypesinvolving defective orthologous genes in man andmouse. Interestingly, in the photoreceptor cells, myosinVIIA is mainly localized in the inner and base of outersegments as well as in the synaptic ending region whereit is co-localized with the synaptic vesicles. Therefore,we suggest that myosin VIIA might play a role in thetrafficking of ribbon-synaptic vesicle complexes andthe renewal processes of the outer photoreceptor disks.INTRODUCTIONUsher syndrome (USH) is an autosomal recessive defect whichaffects both the inner ear and the retina (1). It is regarded as themost frequent cause of deaf-blindness in humans and accounts for3 to 6% of deaf children ( 2,3). Three clinical subtypes have beendescribed, based on the severity of the hearing loss, the presenceor absence of balance problems and the age of onset of the retinitispigmentosa. The most severe form, USH type I (USH1), ischaracterized by profound congenital sensorineural hearing loss,constant vestibular dysfunction and prepubertal onset of retinitispigmentosa leading to blindness. At least four loci have beenassigned to USH1, three of which, USH1A, 1B and 1C, havealready been mapped to chromosomes 14q32, 11q13.5 and 11p15respectively (4–7). We have identified the myosin VIIA gene asresponsible for USH1B (which accounts for about one half of allUSH cases) (8). Mutations in the murine orthologous gene leadto the shaker-1 phenotype (9), characterized by hearingimpairment and balance problems due to damaged cochlear andvestibular neuroepithelia (10,11). However, none of the sixdifferent shaker-1 mutants seems to display any retinal defect(10,11). To explain the discrepancy between the human andmouse retinal phenotypes, several hypotheses can be considered:(i) a difference in the nature of the mutations; (ii) a dissimilaritybetween mouse and human retinal development (12,13); (iii) adifferent influence of modifier genes; (iv) the expression of a genewith redundant function in the mouse retina; (v) an accumulationprocess at the origin of the retinal phenotype, too slow to bedeleterious during the mouse lifetime.The shaker-1 mutations are unlikely to account for the retinalphenotype discrepancy, since at least two of the three mutations

Objective. Accurate modeling of retinal information processing remains a major challenge in retinal physiology with applications in visual rehabilitation and prosthetics. Most of the current artificial retinas are fed with static frame-based information, losing thereby the fundamental asynchronous features of biological vision. The objective of this work is to reproduce the spatial and temporal properties of the majority of ganglion cell (GC) types in the mammalian retina. Approach. Here, we combined an asynchronous event-based light sensor with a model pulling nonlinear subunits to reproduce the parallel filtering and temporal coding occurring in the retina. We fitted our model to physiological data and were able to reconstruct the spatio-temporal responses of the majority of GC types previously described in the mammalian retina (Roska et al 2006 J. Neurophysiol. 95 3810-22). Main results. Fitting of the temporal and spatial components of the response was achieved with high coefficients of determination (median R(2) = 0.972 and R(2) = 0.903, respectively). Our model provides an accurate temporal precision with a reliability of only few milliseconds-peak of the distribution at 5 ms-similar to biological retinas (Berry et al 1997 Proc. Natl Acad. Sci. USA 94 5411-16; Gollisch and Meister 2008 Science 319 1108-11). The spiking statistics of the model also followed physiological measurements (Fano factor: 0.331). Significance. This new asynchronous retinal model therefore opens new perspectives in the development of artificial visual systems and visual prosthetic devices.

A 59-year-old man was admitted for recurrent acute pan­ creatitis. Pancreas divisum was demonstrated at ERCP. The dorsal duct measured 4 mm in diameter in the head of the pancreas and 3 mm in the body. Other causes of acute pan­ creatitis were eliminated by careful radiologic and biologic examinations. Minor papilla therapy was undertaken. To insert a 10F endoprosthesis, 9 cm long with two lateral barbs at each end, into the dorsal duct, the minor papilla was first resected by the technique of endoscopic snare papillectomy. The minor papilla orifice was then dilated with a 7F Soehendra catheter. Stent placement was uneventful. Three months later the patient was symptom free and came back for removal of the pancreatic stent. Surprisingly, duodenos­ copy revealed that the stent had migrated completely into the main pancreatic duct. The pancreatic duct was slightly dilated (5 mm diameter in the head and the body of the pancreas). Repeated endoscopic attempts with the use of Dormia baskets, foreign body grasping forceps, and balloon catheters failed to retrieve the pancreatic stent. The patient was lost to follow-up. Four years later he was hospitalized for an asthmatic attack. During the 4 years he had had no recurrence of abdominal pain. Serum amylase and lipase levels were normal. An ultrasonographic examination showed the prosthesis persisting in the dorsal pancreatic duct. En­ doscopically, the orifice of the minor papilla was open, and we were able to remove the pancreatic stent by using a metal

PURPOSE. The authors recently used topical endoscopy to image the mouse eye fundus. Here, they widened the field of application for this ophthalmologic tool, imaging both the posterior and the anterior eye segments in larger animals commonly encountered in research laboratories and veterinary clinics. METHODS. Pupils were dilated, and local anesthetic and gel were applied to the animal cornea. The endoscopic probe was placed in contact with the cornea of conscious rats, sedated cats and dogs, anesthetized sheep, and nonhuman primates. RESULTS. High-resolution digital images of the eye fundus were obtained in all investigated animals using the endoscopic probe along the eye axis. Arteriovenous filling time was monitored with fluorescein angiography in pigmented rats. The retinal periphery and ciliary bodies could be visualized with the probe placed at an oblique angle. The probe was inclined further to observe the iridocorneal angle such that the pectinate ligaments could be seen at high resolution in cats. The authors used the probe on eyes with retinal detachment, luxation of a cataractous lens, and pigment infiltration in the iridocorneal angle, demonstrating its potential use in eye diseases. CONCLUSIONS. This topical endoscopic technique provides a unique tool for single eye examinations. The authors obtained a circular view of the anterior (iridocorneal angle) and the posterior (fundus) eye segments from all animal species studied. This technique is inexpensive and easy to use. It can be easily moved to the eye of the patient who cannot move to stand in front of classic apparatus, offering new opportunities in ophthalmology. (Invest Ophthalmol Vis Sci. 2008;49: 5168‐5174) DOI:10.1167/iovs.07-1340 I maging eye structures has become essential in diagnostic examinations and follow-up of retinal diseases or lesions in humans and animals. Imaging the eye fundus, for instance, detects retinal detachment, retinal atrophy, and blood vascular occlusion, and examination of the iridocorneal angle can reveal factors underlying an increase in intraocular pressure leading to glaucoma and ganglion cell degeneration. Eye examinations of the cornea, anterior chamber, lens and posterior chamber, and vitreous are usually carried out with a slit lamp apparatus. Images of the eye fundus can then be obtained using indirect ophthalmoscopy or confocal scanning laser ophthalmoscopy (cSLO). 1 These techniques not only provide reflection images of the retina, they generate fluorescent images from natural pigments (autofluorescence) or fluorescent dyes (e.g., fluorescein and indocyanine green) administered to the patient or animal. Such dye-induced images are particularly useful for assessing blood circulation and blood vessel permeability in the retina and the choroid. Anatomic sections of the in vivo retina can be obtained by optic coherence tomography (OCT), a technique recently associated with cSLO. 2 These techniques all use eye optics to visualize the fundus without any contact with the cornea. However, they do not enable the far retinal periphery to be visualized. OCT can provide images of the iridocorneal angle of the eye and ciliary bodies. 3,4 Ultrasound biomacroscopy (UBM) can also provide images of the iridocorneal angle and of the ciliary bodies in humans 5 and mice. 6 To visualize these eye structures for surgery, a goniolens must be used on the cornea to obtain overall circular visualization through indirect ophthalmoscopy. 7,8 However, this approach does not allow a particular area of interest to be targeted by the clinician. We recently described a new endoscopic technique to obtain eye fundus images in the mouse retina. 9 In this study, we extended this low-cost technique to use in larger mammals, including nonhuman primates. Furthermore, we used it to visualize other eye structures, including the iridocorneal angle, in a single examination by simply changing the angle of the endoscopic probe on the cornea.

PURPOSE To describe the time course of microvascular changes after transient branch retinal vein occlusion (BRVO) in rats. METHODS BRVO was induced in pigmented rats by focal laser photocoagulation. The subsequent changes in the retinal angiogram were followed up, both in vivo by confocal scanning laser ophthalmoscopy and ex vivo by confocal microscopy. RESULTS At day 1, capillary closure affected the three microvessel layer differentially, the intermediary layer being the most affected. Collateral veins, which were initiated by the dilation of deep-layer venules, pursued their course below adjacent arteries. These microvascular changes peaked between days 1 and 3. After recanalization at day 3, microvascular changes regressed gradually but incompletely, and at day 30 capillary closure and venule dilation persisted. CONCLUSIONS Transient occlusion of a retinal vein in rats leads to short- and long-term microvascular remodeling upstream of the occlusion site. This study describes a model for the tridimensional arrangement of retinal microvessel that accounts for the topography of the early capillary closure and collateral vessel formation that occur after BRVO. In the long term, these changes regressed incompletely, with recanalization of the occluded vein, suggesting that after a short period of occlusion, microvascular changes may become at least partially independent of flow. Despite the intrinsically limited applicability of this model to human vein occlusion, the results suggest that even if therapeutic decompression of an occluded vein is performed early, it may not reverse capillary dropout completely.

Aim: pancreatic stones are frequently reported to be a factor of failure of endoscopic treatment of chronic pancreatitis. Our series tried to evaluate the efficacy of extracorporeal piezoelectric shock wave lithotripsy (ESWL) to disintegrate pancreatic stones in the main pancreatic duct. Methods- Patients: 51 patients (40 men, 11 women) with a mean age of 51 years, presenting with chronic pancreatitis, have been treated between May 1995 to January 1990. The mean number of sessions of lithotripsy was 4.96 per patient with the piezoelectric lithotriptor EDAP LT02. The mean cumul (power (%) x time (sec) x frequency (shock/sec.) /160) per patient was 70,5 +/- 40,5. The total or uncomplete success was defined by the feasibility ofpancreatic stenting. Results: The fragmentation of stones in the main pancreaticduct was achieved in 83,3 % of cases. The total success was achievedin 25 patients (49%), an uncomplete succcess in 11 patients (21%) and atotal failure in 15 patients (29%). Pancreatic stenting failed in 3/33patients after the ESWL and 10/33 patients before the ESWL. Pain disappearedin 72% of the cases after ESWL. There was a significant relationbetween the fragmentation of stones and the disappearance of pain. A significantrelationship was shown between the cumul value and the fragmentationrate. Conclusion: ESWL with the piezoelectric lithotriptor provides satisfactory results on the disappearance of the pain and on the fragmentation. ESWL seems helpful in the endoscopic treatment of chronic pancreatitis.

Background: Prognosis of IPMT depends on the risk of malignant transformation. The aims of this study were to assess : (1) prognostic factors of malignant IPMT after curative resection, (2) long term survival as compared with patients with "usual" pancreatic adenocarcinoma. Methods: Seventy-three patients (49 men, 24 women, mean age 63 years) underwent surgery for malignant IPMT between 1987 and 1999. Clinical, biochemical, treatment and follow-up were reviewed. Histological data were analysed by one pathologist. Thereafter, 25 patients with invasive malignant IPMT were paired with 25 patients with "usual" pancreatic carcinoma with respect to age and TNM staging, in order to compare survival. Results: Surgical resection consisted of pancreaticoduodenectomy (n=46), distal (n=14), total (n=11) or segmentary (n=2) pancreatectomy. Operative mortality was 4%. Severe dysplasia was found in 22 patients and invasive carcinoma in 51. In patients with invasive carcinoma, lymph node metastasis and peripancreatic extension were present in 33% and 65%, respectively. Mean follow-up after surgery was 33 months. Median survival was 47 months. Three-year survival rates in patients with severe dyplasia and invasive carcinoma were 88% and 43%, respectively. Tumor relapse occurred in 28 patients; 5 patients underwent second tumor resection and 23 had palliative treatment. Postoperative survival was negatively influenced by abdominal pain, high serum CA 19.9 levels, caudal localization, invasive carcinoma, lymph node metastasis and peripancreatic extension. Using multivariate analysis, only lymph node metastasis were associated with an unfavorable prognosis (OR 7.5, p

Aim : The diagnosis of early chronic pancreatitis (ECP) remains difficult and endoscopic ultrasonography (EUS) features are still controversial. The aim of this study was to evaluate the long term follow-up of patients with ECP diagnosed at EUS. Methods : Between 1994 and 1998, 37 patients were diagnosed to have ECP at EUS. All experienced at least one episode of non biliary acute pancreatitis. None had evidence of pancreatic stone on plain film of the abdomen or on CTscanner. The ECP were classified as group A (possible ECP with either parenchymal signs or ductal signs), as group B (probable ECP with both parenchymal and ductal signs) and as group C (certain ECP with pancreatic stones). Results : 11 patients were lost to follow-up, 26 men with median age of 46.5 (23-70) years and median alcohol consumption of 76 ( 0-150) g per day, have been followed for a median duration of 37 (1-94).months. - At the initial examination, 10 patients belonged to group A, 4 to group B and 12 to group C. The pancreatographies (n=24) according to the Cambridge classification were 7 cases in stage 0, 4 cases in stage 1 , 4 cases in stage 2 and 9 cases in stage 3. - At the end of the follow-up, 4 patients underwent surgery (pseudotumorous chronic pancreatitis in 2 cases, duodenal cystic dystrophy in 1 case, and pancreatic cancer complicating chronic pancreatitis in 1 case). 26 patients had clinical evaluation : 12 remained unchanged, 12 had improved health status and 2 still experienced clinical disorders (pain, weight-loss). The final diagnosis of certain ECP was yeldied in 6 out of 10 patients of the group A, in 3 out of 4 patients of the group B and in 9 out of the 12 patients of the group C. Conclusion : The positive predictive value of EUS signs of ECP was 64% in case of possible or probable ECP and 75% in case of certain ECP.

Aims : Long term results of endoscopic pancreatic stenting in pancreas divisum are still debated. The aim of this study was to evaluate the efficacy of dorsal duct stenting and endoscopic papillotomy of the minor papilla in patients presenting with acute recurrent pancreatitis. Patients and methods : Between 1980 and 1998, 34 patients presenting with acute recurrent pancreatitis associated with pancreas divisum were diagnosed. 21 were treated by pancreatic stenting during 11 months (group 1) and 13 were treated by sphincterotomy of the minor papilla (group 2). Results : In group 1, the median of follow-up was 50 ( range 11-105) months. The number of patients presenting with acute pancreatitis before pancreatic stenting, at the end of stenting and at the end of the follow-up was respectively 21/21 (100%), 2/19 (10%) and 2/18 (11%) (p