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Copyright of Nematropica is the property of Organization of Nematologists of Tropical America and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: This study compared the results of exercise Doppler echocardiography (EDE) with right-sided heart catheterization (RHC) and evaluated the combination of EDE and cardiopulmonary exercise testing (CPET) as a screening method for early pulmonary vasculopathy in patients with connective tissue disease.Methods: Patients (N = 52) with connective tissue disease (predominantly systemic sclerosis) and without known pulmonary arterial hypertension underwent both EDE and CPET. If systolic pulmonary arterial pressure (SPAP) was > 40 mm Hg during exercise or peak oxygen uptake (Vo(2)) was < 75% predicted, RHC was suggested.Results: EDE showed an SPAP > 40 mm Hg during exercise in 26/52 patients. Additionally, CPET showed a peak Vo(2) < 75% predicted in 10/26 patients with SPAP 40 mm Hg in 25 patients (n = 1 at rest, n = 24 during exercise). SPAP values assessed by EDE showed no significant difference vs RHC at rest, 25 W, 50 W, and maximal exercise (difference [95% CI]: 0.3 [-2.7; 3.2], -1.3 [-7.1; 4.4], 0.9 [-7.7; 5.9], and -5.6 [-13.5; 2.2] mm Hg). Eight patients with exercise SPAP > 40 mm Hg had an exercise pulmonary arterial wedge pressure > 20 mm Hg, suggesting exercise-induced left ventricular diastolic dysfunction not detectable by EDE.Conclusions: EDE appears to be a reasonable noninvasive method to detect SPAP increase during exercise in connective tissue disease. In combination with CPET, it may be a useful screening tool for early pulmonary vasculopathy, although RHC remains the gold standard for hemodynamic assessment.Trial Registration: clinicaltrials.gov; Identifier: NCT00609349 (Early Recognition of Pulmonary Arterial Hypertension). [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare ganglionic blockade with trimethaphan (TMP) and an alternative drug strategy using combined muscarinic antagonist (glycopyrrolate, GLY) and α-2 agonist (dexmedetomidine, DEX). Protocol 1: incremental phenylephrine was administered during control and combined GLY-DEX, or control and TMP on two control combined GLY and DEX or TMP infusion on two randomized days. Protocol 2: muscle sympathetic nerve activity (MSNA) and the baroreflex MSNA relationship was determined before and after GLY–DEX. Blood pressure was higher with GLY–DEX (99±3 mm Hg) and lower with TMP (78±3 mm Hg) relative to control (GLY–DEX: 90±2 mm Hg; TMP: 91±2 mm Hg;P<0.05). Incremental phenylephrine increased pressure during GLY–DEX (P<0.01 vs control) and TMP (P<0.01 vs control) to a similar degree. Both GLY–DEX and TMP infusion inhibited norepinephrine release (P<0.01 vs control). GLY–DEX inhibited baseline MSNA (P<0.05) and baroreflex changes in MSNA (P<0.01). We conclude that the GLY–DEX alternative drug strategy can be used as a reasonable alternative to pharmacologic ganglionic blockade to examine autonomic cardiovascular control.Clinical Pharmacology & Therapeutics (2008); 83, 5, 692–701. doi:10.1038/sj.clpt.6100326 [ABSTRACT FROM AUTHOR]

Conventional methods for monitoring clinical (epileptiform) multichannel electroencephalogram (EEG) signals often involve morphological, spectral or time-frequency analysis on individual channels to determine waveform features for detecting and classifying ictal events (seizures) and inter-ictal spikes. Blind source separation (BSS) methods, such as independent component analysis (ICA), are increasingly being used in biomedical signal processing and EEG analysis for extracting a set of underlying source waveforms and sensor projections from multivariate time-series data, some of which reflect clinically relevant neurophysiological (epileptiform) activity. The work presents an alternative spatial approach to source tracking and detection in multichannel EEG that exploits prior knowledge of the spatial topographies of the sensor projections associated with the target sources. The target source sensor projections are obtained by ICA decomposition of data segments containing representative examples of target source activity, e.g. a seizure or ocular artifact. Source tracking and detection are then based on the subspace correlation between individual target sensor projections and the signal subspace over a moving window. Different window lengths and subspace correlation threshold criteria reflect transient or sustained target source activity. To study the behaviour and potential application of this spatial source tracking and detection approach, the method was used to detect (transient) ocular artifacts and (sustained) seizure activity in two segments of 25-channel EEG data recorded from one epilepsy patient on two separate occasions, with promising and intuitive results. [ABSTRACT FROM AUTHOR]

Copyright of Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Conventional methods for monitoring clinical (epileptiform) multichannel electroencephalogram (EEG) signals often involve morphological, spectral or time-frequency analysis on individual channels to determine waveform features for detecting and classifying ictal events (seizures) and inter-ictal spikes. Blind source separation (BSS) methods, such as independent component analysis (ICA), are increasingly being used in biomedical signal processing and EEG analysis for extracting a set of underlying source waveforms and sensor projections from multivariate time-series data, some of which reflect clinically relevant neurophysiological (epileptiform) activity. The work presents an alternative spatial approach to source tracking and detection in multichannel EEG that exploits prior knowledge of the spatial topographies of the sensor projections associated with the target sources. The target source sensor projections are obtained by ICA decomposition of data segments containing representative examples of target source activity, e.g. a seizure or ocular artifact. Source tracking and detection are then based on the subspace correlation between individual target sensor projections and the signal subspace over a moving window. Different window lengths and subspace correlation threshold criteria reflect transient or sustained target source activity. To study the behaviour and potential application of this spatial source tracking and detection approach, the method was used to detect (transient) ocular artifacts and (sustained) seizure activity in two segments of 25-channel EEG data recorded from one epilepsy patient on two separate occasions, with promising and intuitive results. [ABSTRACT FROM AUTHOR]

Rationale: High-altitude pulmonary edema (HAPE) is characterized by excessive pulmonary vasoconstriction and is associated with decreased concentrations of nitric oxide (NO) in the lung. Objectives: We hypothesized that individuals susceptible to HAPE (HAPE-S) would also have dysfunction of the vascular NO vasodilator pathway during hypoxia in the systemic vasculature. Methods: During normoxia (FI(O(2)) = 0.21) and 4 hours of normobaric hypoxia (FI(O(2)) = 0.12, corresponding to an altitude of 4,500 m above sea level) endothelium-dependent and endothelium-independent vasodilator responses to intraarterial infusion of acetylcholine (ACh) and sodium nitroprusside, respectively, were measured by forearm venous occlusion plethysmography in nine HAPE-S subjects and in nine HAPE-resistant control subjects. Main Results: Pulmonary artery systolic pressure increased from 22 +/- 3 to 33 +/- 6 mm Hg (p < 0.001) during hypoxia in control subjects, and from 25 +/- 4 to 50 +/- 9 mm Hg in HAPE-S subjects (p < 0.001). Despite similar responses during normoxia in both groups, ACh-induced changes in forearm blood flow markedly decreased during hypoxia in HAPE-S subjects (p = 0.01) but not in control subjects. The attenuated vascular response to ACh infusion during hypoxia inversely correlated with increased pulmonary artery systolic pressure (p = 0.04) and decreased plasma nitrite correlated with attenuated ACh-induced vasodilation in HAPE-S subjects (p = 0.02). Conclusions: Hypoxia markedly impairs vascular endothelial function in the systemic circulation in HAPE-S subjects due to a decreased bioavailability of NO. Impairment of the NO pathway could contribute to the enhanced hypoxic pulmonary vasoconstriction that is central to the pathogenesis of HAPE. [ABSTRACT FROM AUTHOR]

After a period of eccentric exercise of elbow flexor muscles of one arm in young, adult human subjects, muscles became fatigued and damaged. Damage indicators were a fall in force, change in resting elbow angle and delayed onset of soreness. After the exercise, subjects were asked to match the forearm angle of one arm, whose position was set by the experimenter, with their other arm. Subjects matched the position of the unsupported reference arm, when this was unexercised, with a significantly more flexed position in their exercised indicator arm. Errors were in the opposite direction when the reference arm was exercised. The size of the errors correlated with the drop in force. Less consistent errors were observed when the reference arm was supported. A similar pattern of errors was seen after concentric exercise, which does not produce muscle damage. The data suggested that subjects were using as a position cue the perceived effort required to maintain a given forearm angle against the force of gravity. The fall in force from fatigue after exercise meant more effort was required to maintain a given position. That led to matching errors between the exercised and unexercised arms. It was concluded that while a role for muscle spindles in kinaesthesia cannot be excluded, detailed information about static limb position can be derived from the effort required to support the limb against the force of gravity. [ABSTRACT FROM AUTHOR]

Photorefractive self-focusing and self-trapping has proved, over the past decade, to be an efficient low power method able to provide beam control and steering. Over the years, photorefractive Sr x Ba 1 - x Nb 2 O 6 has been shown to be the most promising photorefractive media in this field. Its ability to sustain photorefractive solitons at steady state has been thoroughly investigated. In this paper, the focus is set on the temporal development of self focusing in Sr x Ba 1 - x Nb 2 O 6 , evidencing a soft transition from self-focusing through self-bending and finally optical-branching. This evolution is shown to occur not only as a function of experimental conditions such as electric field applied or beam intensity, but also as a function of time. [ABSTRACT FROM AUTHOR]

Photorefractive self-focusing and self-trapping has proved, over the past decade, to be an efficient low power method able to provide beam control and steering. In this paper, several photorefractive samples are investigated in the aim to provide a comparative study in both continuous wave and pulsed laser light regime. Whereas their holography-like behavior can be thought of as similar, they exhibit strong differences when considering the propagation of a single high contrast narrow beam. Perovskite KNbO 3 and illmenite LiNbO 3 are shown to exhibit respectively self-focusing and self-defocusing features, the latter needing an erasing process to be undertaken for the experiment to be fully reproducible. Finally, Sr x Ba 1 - x Nb 2 O 6 (SBN) is shown to be the most promising sample for applications ranging from optical limiting to all optical routing, though it exhibits instabilities such as optical branching. [ABSTRACT FROM AUTHOR]

In both Parkinson's disease and Huntington's disease, proprioceptive sensory deficits have been suggested to contribute to the motor manifestations of the disease. Here, proprioceptive sensory function was investigated in Parkinson's disease patients, Huntington's disease patients, and healthy control subjects (each group n=8), using proprioception-related evoked potentials. Proprioception-related potentials were elicited by passive index finger movements and measured with high-density EEG. Conventional median nerve somatosensory evoked potentials (mnSEPs) were recorded in the same session. Analysis included amplitude and latency measures from selected scalp electrodes and dipole source reconstruction. We found a proprioception-related N90 component of normal latency in both Parkinson's disease and Huntington's disease. The source strength of the underlying cortical generator was normal in Parkinson's disease, but marginally reduced in Huntington's disease. Using the source location of the N20–P20 component of the mnSEP as a landmark for postcentral area 3b, the N90 was localized to the precentral motor cortex. At a latency around 170–180 ms proprioception-related potentials were explained by bilateral sensory cortex activation with an altered distribution in Parkinson's disease and a reduction of ipsilateral activation in Huntington's disease. Together, the results show largely normal early proprioception-related potentials, but changes in the cortical processing of kinaesthetic signals at longer latencies in both diseases. [ABSTRACT FROM AUTHOR]

The protein clusterin has been suggested to be involved in the pathogenesis of Alzheimer's disease (AD). Its expression is increased in brain regions affected by AD pathology, and to elucidate if there is a concomitant increase of clusterin also in the cerebrospinal fluid (CSF) in different neurological disorders, CSF samples from patients with AD, vascular dementia (VAD), Parkinson's disease (PD), and controls were analysed. Also longitudinal (five occasions) samples from patients with acute stroke were analysed, to follow any degenerative/regenerative phase after acute brain damage. However, there were no changes in CSF-clusterin levels from patients in AD, VAD, PD or acute stroke, as compared to controls. The increase of clusterin in brain tissue is suggested to reflect a regenerative response process, which here is shown not to be followed by a concomitant increase in the CSF. Thus, CSF-clusterin can not be used as an indicator or a diagnostic marker for AD. [ABSTRACT FROM AUTHOR]

Summary. Today, cognitive impairment can be successfully treated with acetylcholine esterase inhibitors (AChE-I) in many, but not all, patients with Alzheimer's disease (AD). To investigate the relation between tacrine treatment, inheritance of ApoE ε4 alleles, and rate of progression, the differences in MMSE and CIBIC scores (efficacy parameters) after 6 and 12 months of tacrine (an AChE-I) treatment were investigated in 145 AD patients. Of these, 84 were ApoE ε4-positive (ApoE4) and 61 were ApoE ε4-negative (ApoE2-3). No differences were found after 6 months of treatment, but after 12 months the CIBIC scores revealed that the ApoE4 patients had declined more than the ApoE2-3 patients (p < 0.05). No differences were found for the last 6 months of treatment. The results primarily suggest a faster rate of decline in the ApoE4 AD compared to the ApoE2-3, but may also reflect that ApoE ε4 genotype inheritance is a negative predictor of treatment effect of tacrine in AD patients. [ABSTRACT FROM AUTHOR]

This work presents a study of the influence of both Bi content and Sb/Bi ratio on the electrical characteristics of a commercial-type ZnO varistor. In contrast to previous studies two nonlinear coefficients, the breakdown fields and energy absorption abilities were measured after sintering at 970°C or 930°C. The Bi-content was varied from 0.9 to 1.8 at% while the Sb/Bi ratio was varied from 0.8 to 1.5, leading to values of up to 104 for the nonlinear coefficient α1, 1100 V mm−1 for the breakdown field and 1137 J cm−3 for the energy absorption ability. The highest α value was measured for the highest Bi-content and the lowest Sb/Bi ratio and vice versa. The breakdown field EV increased with lower sintering temperature, increased Sb/Bi ratio (at a given Bi-content) and increased Bi-content (at a given Sb/Bi ratio). The energy absorption coefficient increased at the higher sinter temperature and with lower Sb and Bi concentrations. The observed effects were related to the amount of spinel phase (Zn7Sb2O12) formed during the sintering process and the amount of liquid phase present during early stages of the sintering process. [ABSTRACT FROM AUTHOR]

Since the very beginning of space physiology research, the deficit in body mass that is often observed after landing has always been interpreted as an indication of the absolute fluid loss early during space missions. However, in contrast to central hypervolemic conditions on Earth, the acute shift of blood volume from the legs to the upper part of the body in astronauts entering µ-gravity (µ-G) has neither stimulated diuresis and natriuresis nor resulted in negative water-and sodium-balances. We therefore examined the kinetics of body mass changes in astronauts (n = 3) during their several weeks aboard the space station MIR. A continuous diet monitoring was performed during the first mission (EuroMIR94, 30 days). The second mission (MIR97, 19 days) comprised a 15-day metabolic ward period (including predefined constant energy and sodium intake). Water and sodium balances were calculated and the kinetic of changes in basal concentrations of fluid-balance-related hormones during flight were determined. The data suggest firstly that loss of body mass during space flight is rather a consequence of hypocaloric nutrition. Secondly, µ-G provokes a sodium retaining hormonal status and may lead to sodium storage without an accompanying fluid retention. [ABSTRACT FROM AUTHOR]

Summary. A polymorphism consisting of a deletion near the 5′ splice site of exon 18 on the α2-macroglobulin (A2M) gene (A2M-2) has been suggested to be associated with Alzheimer's disease (AD) in family-based studies. We studied the A2M-2 allele together with the ApoE alleles in a large series on patients with AD (n = 449) and age-matched controls (n = 349). Neuropathologically confirmed diagnoses were available in 199 cases (94 AD and 107 control cases). We found no increase in A2M-2 genotype or allele frequencies in AD (27.5% and 14.6%) versus controls (26.4% and 14.9%). In contrast, a marked increase (p < 0.0001) in ApoE ε4 genotype or allele frequencies was found in AD (66.6% and 41.2%) as compared with controls (29.8% and 16.5%), suggesting sufficient statistical power in our sample. No relation was found between the A2M-2 and the ApoE ε4 allele. No change in A2M exon 17–18 mRNA size or sequence or A2M protein size was found in cases carrying the A2M-2 deletion, suggesting that there is no biological consequences of the A2M intronic deletion. No change in A2M protein level in cerebrospinal fluid was found in AD, suggesting that the A2M-2 allele does not effect the A2M protein expression in the brain. The lack of an association between the A2M-2 allele and AD in the present study, and the lack of abnormalities in the A2M mRNA or protein suggest that the A2M-2 allele is not associated with AD. [ABSTRACT FROM AUTHOR]

The engineering sciences have long been interested in models describing the settling (or sedimentation) of particle ensembles in viscous fluids. From a theoretical point of view, sedimentation constitutes a two phase many-body phenomenon with complex interaction and as such has proved to be quite inaccessible to modelling attempts with relevance in applications. A stochastic model was introduced by Pickard and Tory in 1977 and was subsequently revised. In this paper we expand and refine the stochastic model and present a satisfactory model-fitting procedure and parameter estimators based on transit times of sedimenting particles. [ABSTRACT FROM AUTHOR]

Objectives: Biochemical markers for Alzheimer's disease would be of great value, especially to help in diagnosis early in the course of the disease. A pronounced increase in CSF tau protein (CSF-tau) is found in most patients with Alzheimer's disease. However, the specificity has to be further studied, as an increase in CSF-tau has also been found in other dementias, especially in vascular dementia. As most previous CSF studies have been based on selected inpatients, it was considered of special interest to examine the diagnostic potential of CSF-tau in a community population based sample of consecutive patients with dementia. Such patient material has been examined at the Piteå River Valley Hospital in Northern Sweden since 1986, and includes all those with memory disturbances in the community. The aim was also to study if an increase in CSF-tau is found early in the disease process, and whether CSF-tau changes during the progression of disease.Methods: Participants: Community population based sample of 75 demented patients (43 with Alzheimer's disease, 21 with vascular dementia, and 11 with mixed Alzheimer's disease/vascular dementia), 18 healthy subjects, and 18 neurological controls. A follow up investigation (including analysis of a new CSF sample) was performed in all patients after about one year.Main Outcome Measures: Concentrations of total (both normal tau and PHF-tau) tau in CSF, clinical measures (duration and severity of dementia), and apoE polymorphism.Results: CSF-tau was markedly increased in Alzheimer's disease, 41/43 (95%) patients had values above the cut off level (mean+2 SD) in controls (306 pg/ml). High CSF-tau concentrations were also found in most patients with vascular dementia, preferentially in patients with vascular dementia without progressive leukoaraiosis on CT, whereas patients with vascular dementia with progressive leukoaraiosis had normal CSF-tau. Concentrations of CSF-tau were stable at one year follow up in both patients with Alzheimer's disease and patients with vascular dementia, and there was no correlation between CSF-tau and either duration or severity of dementia.Conclusions: The findings confirm the high sensitivity of CSF-tau for the diagnosis of Alzheimer's disease, but high CSF-tau was also found in vascular dementia, resulting in a lower specificity. However, high CSF-tau is preferentially found in patients with vascular dementia without progressive leukoaraiosis, which may constitute a group with concomitant Alzheimer's disease pathology. High CSF-tau may be present during the whole course of the disease in Alzheimer's disease. Possibly, therefore, the same high CSF-tau concentrations may be present before the onset of clinical dementia. Follow up studies on such patients will tell whether analysis of CSF-tau is useful as a biochemical marker for early Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Objectives: To study the association of apoE genotypes with dementia and cerebrovascular disorders in a population based sample of 85 year old people.Methods: A representative sample of 85 year old people (303 non-demented, 109 demented) were given a neuropsychiatric and a medical examination and head CT. The apoE isoforms were determined. Dementia was diagnosed according to DSM-III-R.Results: At the age of 85, carriers of the apoE epsilon4 allele had an increased odds ratio (OR) for dementia (1.9; p<0.01) and its subtypes Alzheimer's disease (1.9; p<0.05) and vascular dementia (2.0; p<0.05). Among those categorised as having vascular dementia, the apoE epsilon4 allele was associated with mixed Alzheimer's disease-multi-infarct dementia (OR 6.5; p<0.05), but not with pure multi-infarct dementia (OR 1.5; NS). Only carriers of the apoE epsilon4 allele who also had ischaemic white matter lesions on CT of the head had an increased OR for dementia (OR 6.1; p=0.00003), and its main subtypes Alzheimer's disease (OR 6.8; p=0.002) and vascular dementia (OR 5.6; p=0.0007), whereas carriers of the apoE epsilon4 allele without white matter lesions had an OR for dementia of 1.0 (OR for Alzheimer's disease 1.8; NS and for vascular dementia 0.6; NS) and non-carriers of the apoE epsilon4 allele with white matter lesions had an OR for dementia of 2.2; NS (OR for Alzheimer's disease 2.7; NS and for vascular dementia 1.6; NS). The apoE allele variants were not related to mortality or incidence of dementia between the ages of 85 and 88. The epsilon2 allele was related to a higher prevalence of stroke or transient ischaemic attack at the age of 85 (OR 2.1; p<0.05) and a higher incidence of multi-infarct dementia during the follow up (OR 2.9; p<0.05).Conclusions: Neither the apoE epsilon4 allele nor white matter lesions are sufficient risk factors by themselves for dementia at very old ages, whereas possession of both these entities increases the risk for Alzheimer's disease and vascular dementia substantially. [ABSTRACT FROM AUTHOR]

Background: In Rotterdam 304 heart transplants have been performed since 1984. End-stage renal failure, necessitating renal replacement therapy, has developed in 24 patients (8%) after an interval of 25-121 months (median 79 months). After starting renal replacement therapy one-year survival was only 60%. Overall survival after heart transplantation, however, was favourable: 5 and 10 year survival rates of 79% and 50% respectively. [ABSTRACT FROM PUBLISHER]

This study deals with the space and time distribution of human leukaemia. It took place in seven rural French regions and concerns the six main types of leukaemias and haematosarcomas. The investigation on clustering tendency was carried out using several different methods—principally the simulation method and Knox's and Mantel's approaches. The overall analysis suggests that no clustering tendency is indicated in any and for any haematological disease. Some points which may be linked with these negative results are discussed. [ABSTRACT FROM PUBLISHER]

Copyright of Neurosurgical Review is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In three groups of patients, one with no signs of pulmonary edema (n = 11), one with acute myocardial infarction but without pulmonary edema (n = 6) and one with recent myocardial infarction and clinical signs of pulmonary edema (n = 13), investigations were performed to determine the degree of pulmonary edema: Pulmonary capillary wedge pressure (PC W), plasma colloid osmotic pressure (COP), and critical pressure (CrP) defined as CrP = PCW − COP. The double indicator dilution method with / albumin as an intravascular indicator and tritiated water (THO) as a diffusing indicator. Clinical estimates such as radiological and auscultatory criteria. Monitoring of PCW and plasma COP appears to give valuable information on whether or not pulmonary edema fluid is being generated at the moment when these measurements are being made. On the other hand, the information obtained by the double indicator-dilution method proved insufficient to warrant its adoption for routine clinical use. Even the difference in mean transit limes of the two indicators was found to be a better measurement of the degree of pulmonary edema. [ABSTRACT FROM PUBLISHER]

Stereoselectivity in the oxidation of ferrocenyl sulphides with several species of microorganisms such as Corynebacterium equi was reversed between (methylthiomethyl)ferrocene and ( t-butylthiomethyl)ferrocene, indicating that the size of the side chain could control the stereochemical course of the biooxidation. The size seems to be effective within some limit, because the more bulky compound, (phenylthiomethyl)ferrocene, was a poor substrate. On the other hand, the microbial oxidation of (methylthiomethyl)ruthenocene and -osmocene with Mortierella isabellina and that of ( t-butylthiomethyl)ruthenocene and -osmocene with C. equi gave levorotatory sulphoxides (85-97% e.e.), which were all found to have R absolute configuration. These stereoselectivities were the same as those for the corresponding ferrocenyl sulphides. Thus, the central atom of the metallocenic sulphides seems not to affect the stereoselectivity in the biooxidation. The microbial oxidation is a useful method to prepare several kinds of chiral metallocenic sulphoxides with high optical purity. [ABSTRACT FROM AUTHOR]

Donor-specific CTL present within the cardiac allograft during a rejection episode are distinct from those that populate the cardiac allograft in the absence of rejection. Whereas the former generally have a high avidity for donor cells, the latter mainly have a low avidity for donor cells. This observation made us reason that high-avidity CTL are implicated in transplant rejection, whereas low-avidity CTL are not. In the present study, we analyse whether both CTL subsets were distinct with respect to their IL-2, IL-4, IL-6 and interferon-gamma (IFN-γ) secretion pattern. CTL clones with either a high or a low avidity for donor antigens were stimulated with donor cells, third party cells, or immobilized anti-CD3 MoAb and the amount of cytokine released was measured. High- and low-avidity CTL clones were found to differ with respect to their IFN-γ production profile. Stimulation with donor cells resulted in IFN-γ secretion by high-avidity CTL clones, but not by low-avidity CTL clones. CD3 stimulation, in contrast, led to secretion of equivalent amounts of IFN-γ by both CTL subsets. These observations indicate that low-avidity CTL are fully capable of producing IFN-γ, but, in contrast to high avidity CTL, fail to do so when they encounter donor cells. As IFN-γ favours the occurrence of transplant rejection, this observation emphasizes the relevance of high-avidity CTL in the rejection process. Additionally, the data show that the cytokine production profile of CTL depends on the nature of the stimulus. [ABSTRACT FROM AUTHOR]