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The Maintenance of Lipid Asymmetry (Mla) pathway is a multicomponent system found in all gram-negative bacteria that contributes to virulence, vesicle blebbing and preservation of the outer membrane barrier function. It acts by removing ectopic lipids from the outer leaflet of the outer membrane and returning them to the inner membrane through three proteinaceous assemblies: the MlaA-OmpC complex, situated within the outer membrane; the periplasmic phospholipid shuttle protein, MlaC; and the inner membrane ABC transporter complex, MlaFEDB, proposed to be the founding member of a structurally distinct ABC superfamily. While the function of each component is well established, how phospholipids are exchanged between components remains unknown. This stands as a major roadblock in our understanding of the function of the pathway, and in particular, the role of ATPase activity of MlaFEDB is not clear. Here, we report the structure of E. coli MlaC in complex with the MlaD hexamer in two distinct stoichiometries. Utilising in vivo complementation assays, an in vitro fluorescence-based transport assay, and molecular dynamics simulations, we confirm key residues, identifying the MlaD β6-β7 loop as essential for MlaCD function. We also provide evidence that phospholipids pass between the C-terminal helices of the MlaD hexamer to reach the central pore, providing insight into the trajectory of GPL transfer between MlaC and MlaD., (© 2024. The Author(s).)

The E. coli Paraquat Inducible (Pqi) Pathway is a putative Gram-negative phospholipid transport system. The pathway comprises three components: an integral inner membrane protein (PqiA), a periplasmic spanning MCE family protein (PqiB) and an outer membrane lipoprotein (PqiC). Interactions between all complex components, including stoichiometry, remain uncharacterised; nevertheless, once assembled into their quaternary complex, the trio of Pqi proteins are anticipated to provide a continuous channel between the inner and outer membranes of diderms. Here, we present X-ray structures of both the native and a truncated, soluble construct of the PqiC lipoprotein, providing insight into its biological assembly, and utilise neutron reflectometry to characterise the nature of the PqiB-PqiC-membrane interaction. Finally, we employ phenotypic complementation assays to probe specific PqiC residues, which imply the interaction between PqiB and PqiC is less intimate than previously anticipated., (© 2024. The Author(s).)

New Findings: What is the topic of this review? We review barosensory vessel mechanics and their role in blood pressure regulation across the lifespan. What advances does it highlight? In young normotensive men, aortic unloading mechanics contribute to the resting operating point of the vascular sympathetic baroreflex; however, with advancing age, this contribution is removed. This suggests that barosensory vessel unloading mechanics are not driving the well-documented age-related increase in resting muscle sympathetic nerve activity., Abstract: An age-associated increase in arterial blood pressure is evident for apparently healthy humans. This is frequently attributed to stiffening of the central arteries and a concurrent increase in sympathetic outflow, potentially mediated by a reduced ability of the baroreceptive vessels to distend. This is supported, in part, by a reduced mechanical component of the vascular sympathetic baroreflex (i.e., a reduction in distension for a given pressure). Previous characterization of the mechanical component has assessed only carotid artery distension; however, evidence suggests that both the aortic and carotid baroreflexes are integral to blood pressure regulation. In addition, given that baroreceptors are located in the vessel wall, the change in wall tension, comprising diameter, pressure and vessel wall thickness, and the mechanics of this change might provide a better index of the baroreceptor stimulus than the previous method used to characterize the mechanical component that relies on diameter alone. This brief review summarizes the data using this new method of assessing barosensory vessel mechanics and their influence on the vascular sympathetic baroreflex across the lifespan., (© 2023 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Autophagy is a homeostatic process critical for cellular survival, and its malfunction is implicated in human diseases including neurodegeneration. Loss of autophagy contributes to cytotoxicity and tissue degeneration, but the mechanistic understanding of this phenomenon remains elusive. Here, we generated autophagy-deficient (ATG5 -/- ) human embryonic stem cells (hESCs), from which we established a human neuronal platform to investigate how loss of autophagy affects neuronal survival. ATG5 -/- neurons exhibit basal cytotoxicity accompanied by metabolic defects. Depletion of nicotinamide adenine dinucleotide (NAD) due to hyperactivation of NAD-consuming enzymes is found to trigger cell death via mitochondrial depolarization in ATG5 -/- neurons. Boosting intracellular NAD levels improves cell viability by restoring mitochondrial bioenergetics and proteostasis in ATG5 -/- neurons. Our findings elucidate a mechanistic link between autophagy deficiency and neuronal cell death that can be targeted for therapeutic interventions in neurodegenerative and lysosomal storage diseases associated with autophagic defect., Competing Interests: Declaration of interests R.J. is cofounder of Fate Therapeutics, Fulcrum Therapeutics, and Omega Therapeutics and advisor to Dewpoint Therapeutics. E.S. is founder of NMN Bio Ltd. V.I.K. is a scientific advisor for Longaevus Technologies., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Mitochondrial dysfunction involving mitochondria-associated ER membrane (MAM) dysregulation is implicated in the pathogenesis of late-onset neurodegenerative diseases, but understanding is limited for rare early-onset conditions. Loss of the MAM-resident protein WFS1 causes Wolfram syndrome (WS), a rare early-onset neurodegenerative disease that has been linked to mitochondrial abnormalities. Here we demonstrate mitochondrial dysfunction in human induced pluripotent stem cell-derived neuronal cells of WS patients. VDAC1 is identified to interact with WFS1, whereas loss of this interaction in WS cells could compromise mitochondrial function. Restoring WFS1 levels in WS cells reinstates WFS1-VDAC1 interaction, which correlates with an increase in MAMs and mitochondrial network that could positively affect mitochondrial function. Genetic rescue by WFS1 overexpression or pharmacological agents modulating mitochondrial function improves the viability and bioenergetics of WS neurons. Our data implicate a role of WFS1 in regulating mitochondrial functionality and highlight a therapeutic intervention for WS and related rare diseases with mitochondrial defects., Competing Interests: Conflict of interests The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Mitochondria are responsible for many vital pathways governing cellular homeostasis, including cellular energy management, heme biosynthesis, lipid metabolism, cellular proliferation and differentiation, cell cycle regulation, and cellular viability. Electron transport and ADP phosphorylation coupled with proton pumping through the mitochondrial complexes contribute to the preservation of mitochondrial membrane potential (ΔΨ m ). Importantly, mitochondrial polarization is essential for reactive oxygen species (ROS) production and cytosolic calcium (Ca 2+ ) handling. Thus, changes in mitochondrial oxidative phosphorylation (OXPHOS), ΔΨ m , and ATP/ADP may occur in parallel or stimulate each other. Brain cells like neurons are heavily reliant on mitochondrial OXPHOS for its high-energy demands, and hence improper mitochondrial function is detrimental for neuronal survival. Indeed, several neurodegenerative disorders are associated with mitochondrial dysfunction. Modeling this disease-relevant phenotype in neuronal cells differentiated from patient-derived human induced pluripotent stem cells (hiPSCs) provide an appropriate cellular platform for studying the disease pathology and drug discovery. In this review, we describe high-throughput analysis of crucial parameters related to mitochondrial function in hiPSC-derived neurons. These methodologies include measurement of ΔΨ m , intracellular Ca 2+ , oxidative stress, and ATP/ADP levels using fluorescence probes via a microplate reader. Benefits of such an approach include analysis of mitochondrial parameters on a large population of cells, simultaneous analysis of different cell lines and experimental conditions, and for drug screening to identify compounds restoring mitochondrial function., (© 2022. Springer Science+Business Media, LLC.)

The outer membrane of Gram-negative bacteria presents a robust physicochemical barrier protecting the cell from both the natural environment and acting as the first line of defense against antimicrobial materials. The proteins situated within the outer membrane are responsible for a range of biological functions including controlling influx and efflux. These outer membrane proteins (OMPs) are ultimately inserted and folded within the membrane by the β-barrel assembly machine (Bam) complex. The precise mechanism by which the Bam complex folds and inserts OMPs remains unclear. Here, we have developed a platform for investigating Bam-mediated OMP insertion. By derivatizing a gold surface with a copper-chelating self-assembled monolayer, we were able to assemble a planar system containing the complete Bam complex reconstituted within a phospholipid bilayer. Structural characterization of this interfacial protein-tethered bilayer by polarized neutron reflectometry revealed distinct regions consistent with known high-resolution models of the Bam complex. Additionally, by monitoring changes of mass associated with OMP insertion by quartz crystal microbalance with dissipation monitoring, we were able to demonstrate the functionality of this system by inserting two diverse OMPs within the membrane, pertactin, and OmpT. This platform has promising application in investigating the mechanism of Bam-mediated OMP insertion, in addition to OMP function and activity within a phospholipid bilayer environment., (Copyright © 2021 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

The polymeric mucin MUC5B provides the structural and functional framework of respiratory mucus, conferring both viscoelastic and antimicrobial properties onto this vital protective barrier. Whilst it is established that MUC5B forms disulfide-linked linear polymers, how this relates to their packaging in secretory granules, and their molecular form in mucus remain to be fully elucidated. Moreover, the role of the central heavily O-glycosylated mucin domains in MUC5B conformation is incompletely described. Here we have completed a detailed structural analysis on native MUC5B polymers purified from saliva and subsequently investigated how MUC5B conformation is affected by changes in calcium concentration and pH, factors important for mucin intragranular packaging and post-secretory expansion. The results identify that MUC5B has a beaded structure repeating along the polymer axis and suggest that these repeating motifs arise from distinct glycosylation patterns. Moreover, we demonstrate that the conformation of these highly entangled linear polymers is sensitive to calcium concentration and changes in pH. In the presence of calcium (Ca 2+ , 10 mM) at pH 5.0, MUC5B adopted a compact conformation which was lost either upon removal of calcium with EGTA, or by increasing the pH to 7.4. These results suggest a pathway of mucin collapse to enable intracellular packaging and mechanisms driving mucin expansion following secretion. They also point to the importance of the tight control of calcium and pH during different stages of mucin biosynthesis and secretion, and in the generation of correct mucus barrier properties.

The Mla pathway is believed to be involved in maintaining the asymmetrical Gram-negative outer membrane via retrograde phospholipid transport. The pathway is composed of three components: the outer membrane MlaA-OmpC/F complex, a soluble periplasmic protein, MlaC, and the inner membrane ATPase, MlaFEDB complex. Here, we solve the crystal structure of MlaC in its phospholipid-free closed apo conformation, revealing a pivoting β-sheet mechanism that functions to open and close the phospholipid-binding pocket. Using the apo form of MlaC, we provide evidence that the inner-membrane MlaFEDB machinery exports phospholipids to MlaC in the periplasm. Furthermore, we confirm that the phospholipid export process occurs through the MlaD component of the MlaFEDB complex and that this process is independent of ATP. Our data provide evidence of an apparatus for lipid export away from the inner membrane and suggest that the Mla pathway may have a role in anterograde phospholipid transport.

In bacteria, the translocation of proteins across the cytoplasmic membrane by the Sec machinery requires the ATPase SecA. SecA binds ribosomes and recognises nascent substrate proteins, but the molecular mechanism of nascent substrate recognition is unknown. We investigated the role of the C-terminal tail (CTT) of SecA in nascent polypeptide recognition. The CTT consists of a flexible linker (FLD) and a small metal-binding domain (MBD). Phylogenetic analysis and ribosome binding experiments indicated that the MBD interacts with 70S ribosomes. Disruption of the MBD only or the entire CTT had opposing effects on ribosome binding, substrate-protein binding, ATPase activity and in vivo function, suggesting that the CTT influences the conformation of SecA. Site-specific crosslinking indicated that F399 in SecA contacts ribosomal protein uL29, and binding to nascent chains disrupts this interaction. Structural studies provided insight into the CTT-mediated conformational changes in SecA. Our results suggest a mechanism for nascent substrate protein recognition., Competing Interests: MJ, TK, SW, DW, FM, KR, MW, GH, GK, BB, DH No competing interests declared, (© 2019, Jamshad et al.)

Cystic fibrosis (CF) is characterized by increased mucus viscosity and delayed mucociliary clearance that contributes to progressive decline of lung function. Mucus in the respiratory and GI tract is excessively adhesive in the presence of airway dehydration and excess extracellular Ca2+ upon mucin release, promoting hyperviscous, densely packed mucins characteristic of CF. Therapies that target mucins directly through ionic interactions remain unexploited. Here we show that poly (acetyl, arginyl) glucosamine (PAAG), a polycationic biopolymer suitable for human use, interacts directly with mucins in a Ca2+-sensitive manner to reduce CF mucus viscoelasticity and improve its transport. Notably, PAAG induced a linear structure of purified MUC5B and altered its sedimentation profile and viscosity, indicative of proper mucin expansion. In vivo, PAAG nebulization improved mucociliary transport in CF rats with delayed mucus clearance, and cleared mucus plugging in CF ferrets. This study demonstrates the potential use of a synthetic glycopolymer PAAG as a molecular agent that could benefit patients with a broad array of mucus diseases.

Aim: There is a requirement of an expansive and up to date review of surgical management of inflammatory bowel disease (IBD) that can dovetail with the medical guidelines produced by the British Society of Gastroenterology., Methods: Surgeons who are members of the ACPGBI with a recognised interest in IBD were invited to contribute various sections of the guidelines. They were directed to produce a procedure based document using literature searches that were systematic, comprehensible, transparent and reproducible. Levels of evidence were graded. An editorial board was convened to ensure consistency of style, presentation and quality. Each author was asked to provide a set of recommendations which were evidence based and unambiguous. These recommendations were submitted to the whole guideline group and scored. They were then refined and submitted to a second vote. Only those that achieved >80% consensus at level 5 (strongly agree) or level 4 (agree) after 2 votes were included in the guidelines., Results: All aspects of surgical care for IBD have been included along with 157 recommendations for management., Conclusion: These guidelines provide an up to date and evidence based summary of the current surgical knowledge in the management of IBD and will serve as a useful practical text for clinicians performing this type of surgery., (© 2018 Authors. Colorectal Disease published by John Wiley & Sons Ltd on behalf of Association of Coloproctology of Great Britain and Ireland.)

Gastrointestinal nematodes, such as Trichuris trichiura (human whipworm), are a major source of morbidity in humans and their livestock. There is a paucity of commercially available vaccines against these parasites, and vaccine development for T. trichiura has been impeded by a lack of known host protective antigens. Experimental vaccinations with T. muris (murine whipworm) soluble Excretory/Secretory (ES) material have demonstrated that it is possible to induce protective immunity in mice; however, the potential for extracellular vesicles (EVs) as a source of antigenic material has remained relatively unexplored. Here, we demonstrate that EVs isolated from T. muris ES can induce protective immunity in mice when administered as a vaccine without adjuvant and show that the protective properties of these EVs are dependent on intact vesicles. We also identified several proteins within EV preparations that are targeted by the host antibodies following vaccination and subsequent infection with T. muris. Many of these proteins, including VWD and vitellogenin N and DUF1943-domain-containing protein, vacuolar protein sorting-associated protein 52 and TSP-1 domain-containing protein, were detected in both soluble ES and EV samples and have homologues in other parasites of medical and veterinary importance, and as such are possible protective antigens., (© 2018 The Authors. Parasite Immunology Published by John Wiley & Sons Ltd.)

Mucosal surfaces represent critical routes for entry and exit of pathogens. As such, animals have evolved strategies to combat infection at these sites, in particular the production of mucus to prevent attachment and to promote subsequent movement of the mucus/microbe away from the underlying epithelial surface. Using biochemical, biophysical, and infection studies, we have investigated the host protective properties of the skin mucus barrier of the Xenopus tropicalis tadpole. Specifically, we have characterized the major structural component of the barrier and shown that it is a mucin glycoprotein (Otogelin-like or Otogl) with similar sequence, domain organization, and structural properties to human gel-forming mucins. This mucin forms the structural basis of a surface barrier (∼6 μm thick), which is depleted through knockdown of Otogl. Crucially, Otogl knockdown leads to susceptibility to infection by the opportunistic pathogen Aeromonas hydrophila To more accurately reflect its structure, tissue localization, and function, we have renamed Otogl as Xenopus Skin Mucin, or MucXS. Our findings characterize an accessible and tractable model system to define mucus barrier function and host-microbe interactions., Competing Interests: The authors declare no conflict of interest., (Copyright © 2018 the Author(s). Published by PNAS.)

The effect of introducing an external cephalic version (ECV) clinic was evaluated after 12 months. The practical procedure of establishing the clinic, its protocol and the technique of ECV is described. All women had singleton pregnancies of at least 36 weeks gestation. There were 61 'primary' attempts at ECV, and one repeat attempt. The operator performing the majority of the ECVs had a 56% success rate, whilst the overall rate for the clinic was 53%. There was minimal fetal and maternal morbidity. Success according to placental site, parity, gestation and type of breech as well as the mode of delivery and neonatal outcome of all patients on whom ECV was attempted is presented. There was a significant decrease in the total number of breech deliveries, mainly through a 60% reduction in emergency caesarean section. The cost effectiveness of the clinic and the use of tocolytics is discussed.

Over the past 10-15 years, workers using conventional computing approaches have attempted to provide an accurate assessment of fetal condition during labour based on the cardiotocogram (CTG) alone. These have not proved successful perhaps because the correct interpretation of fetal condition also requires physiological knowledge, specific patient information, knowledge of events during labour and considerable practical experience. An intelligent system which considers all the relevant information and embodies expertise may better diagnose fetal condition and support decision making. This study reports the preliminary evaluation of such a system and investigates whether this approach can attain a performance comparable with experienced local clinicians. From a database of 200 high risk labour records, 30 cases were selected; the 9 cases which received clinical intervention for 'fetal-distress' and a further 21 cases selected randomly. The management specified by the system, 3 experienced clinicians (A, B and C) and the actual clinical management were compared in a retrospective blinded review. The experts were found to agree well with each other. Expert A reviewed the cases five months later and was found to be entirely consistent in the management of 28 of the 30 cases. The system's actions were indistinguishable from the experts' and in no case did the system recommend an action not also recommended by at least one experienced reviewer. This study demonstrates the potential of an intelligent system to assist in the management of labour.

Detectors for scanning video (10-MHz) imagers should be chosen for their high quantum efficiency and internal gain. Because of the high bandwidth both photomultiplier tubes and avalanche photodiodes are limited by photon noise, so that dark noise is not the determining quantity.

Purpose: Excess morbidity and mortality due to asthma, aggravated by demonstrably poor patient self-management practices, suggest the need for formal patient education programs. Individual and group asthma education programs were developed and evaluated to determine their cognitive, behavioral, and clinical effects., Patients and Methods: We compared changes in asthma symptoms, utilization of medical services, knowledge about asthma, metered-dose inhaler (MDI) technique, and self-management behaviors for 323 adult Kaiser Permanente patients with moderate to severe asthma who were randomly assigned to small-group education, individual teaching, or 1 of 2 control conditions--an information (workbook) control or usual control (no formal asthma education). Data were collected from patients by questionnaire, diary, and physical examination at enrollment and at 5 months and 1 year after intervention. Medical record data on these patients were abstracted for a total 3-year period, from 1 year before to 2 years after enrollment., Results: Compared with the usual control, the self-management education programs were associated with significant improvements in control of asthma symptoms (reduced "bother" due to asthma and increased symptom-free days), MDI technique, and environmental control practices. Small-group education also was associated with significant improvements in physician evaluation of the patients' asthma status and in patients' level of physical activity. For both group and individual education recipients, improvement in MDI technique was positively correlated with improved control of symptoms; however, the degree of improvement in symptoms was greater than that which could be accounted for on the basis of improvement in MDI technique alone. The time course over which changes occurred in the various outcome measures suggests the mechanism by which education resulted in improvement in the patient's status. Significant improvements in MDI technique and environmental control practices were manifest immediately following education (5-month follow-up) and at the 1-year follow-up. Significant improvements in symptom measures were not apparent until the 1-year follow-up. The rate of utilization of medical care for acute exacerbations decreased between baseline and the 2-year follow-up period, but this decrease did not differ significantly among treatment conditions. However, there was a trend toward greater reduction in patients receiving small-group education. An ad hoc finding of a significant difference favoring small-group education between the baseline and the second follow-up year acute visit rates was observed. This result must be regarded as tentative, since it is not clear that unambiguous statistical significance is attained in the light of multiplicity issues. However, this trend is consistent with the antecedent benefits of the small-group education, and appears to warrant further investigation., Conclusions: Carefully designed asthma education programs for adults can improve patients' understanding of their condition and its treatment and increase their motivation and confidence that the condition can be controlled, thereby increasing their adherence to the treatment regimen and management of symptoms, and, in turn, improving control of symptoms. Both small-group education and individual education were associated with significant benefits, but the group program was simpler to administer, better received by patients and educators, and more cost-effective. The results show promise for improving clinical outcomes, through well-designed educational programs, for patients with asthma and other chronic health problems.

In the pursuit of gains in muscle size and strength, body-builders may mistakenly use illicit drugs believing them to be anabolic steroids. The case described illustrates the physical and psychological dangers of such behaviour.

We describe noninvasive techniques to optimize reflectometry measurements, particularly retinal densitometry, which measures the photopigment density difference. With these techniques unwanted scattered light is greatly reduced, and the retina is visualized during measurements. Thus results may be compared for each retinal location, and visible artifacts are minimized. The density difference measurements of the cone photopigment depend on the optical configuration of the apparatus. The cone photopigment density difference is greatest near the fovea and for most observers decreases rapidly with eccentricity. A research version for reflectometry and psychophysics of the scanning laser ophthalmoscope is described.

The scanning laser ophthalmoscope can be modified to operate as a scanning laser biomicroscope for use in anterior segment fluorescein angiography. The substantial depth of focus, large field of view, co-axial illumination, low light levels, real-time television operation, and videorecording with immediate recall provide advantages not available with conventional photographic methods. Video techniques give a resolution slightly inferior to photography, but this is unlikely to be significant in clinical practice. A technique of traversing the entire anterior episcleral vasculature has been developed to give a comprehensive and reproducible angiographic record. Previous fluorescein studies suggesting the primary importance of retrograde (centrifugal) flow in the perforating anterior ciliary arteries were not supported; methodologic explanations are advanced. Several principles are proposed to improve techniques of anterior segment angiography.

The referral and management of parasuicide patients from urban and rural areas were compared in a retrospective study of hospital and general practice records. Whereas most urban patients were physically and psychiatrically managed in general hospitals, the majority of rural patients were managed at home or in cottage hospitals by general practitioners. The overall parasuicide rate of the rural population was found to be similar to that of the city. Although there were no clinical differences between the two groups of patients, relatively more middleaged rural patients were admitted to hospital. The results suggest that parasuicide is now as commonly seen in rural situations, but that the problem is managed outside district general hospitals by general practitioners.

The purpose of the AIR/Kaiser-Permanente asthma project is to evaluate various approaches to the education of adults with asthma, identifying those types of patients for whom particular approaches are most cost effective. Critical self-management practices for adults with asthma were identified using the critical incident technique. An individualized and a group administered educational program are being developed to teach the identified critical skills, using the instructional models previously employed in AIR WISE and AIR POWER programs for children with asthma. Three hundred patients with moderate to severe asthma from Northern California Kaiser-Permanente Medical Group clinics will participate in a trial of these programs. Patients will be randomly assigned to one of four conditions: One of two educational programs, an information/attention control, or a data-only control condition. Data will be collected on all patients for 15 months; health care utilization data covering a two-year period will be available from medical records. Program effectiveness will be evaluated in terms of pre-post changes in the patients' knowledge, attitudes, self-management practices, medical condition, daily functioning, and utilization of services. Cost effectiveness will be evaluated, paying specific attention to the cost effectiveness of different educational approaches for different types of patients.

A confocal scanning imager moves an illumination spot over the object and a (virtual) detector synchronously over the image. In the confocal scanning laser ophthalmoscope this is accomplished by reusing the source optics for detection. The common optical elements are all mirrors-either flat or spherical-and the scanners are positioned to compensate astigmatism due to mirror tilt. The source beam aperture at the horizontal scanner is small. Light returning from the eye is processed by the same elements, but now the polygon's facet is overfilled. A solid-state detector may be at either a pupillary or retinal conjugate plane in the descanned beam and still have proper throughput matching. Our 1-mm avalanche photodiode at a pupillary plane is preceded by interchangeable stops at an image (retinal) plane. Not only can we reject scattered light to a degree unusual for viewing the retina, but we choose selectively among direct and scattered components of the light returning from the eye. One (of many) consequences is that this ophthalmoscope gives crisp and complete retinal images in He-Ne light without dilation of the pupil.

The scanning laser ophthalmoscope (SLO) system has been modified to permit direct retinal perimetry. A movable pinhole in a retinal conjugate plane furnishes a mapping stimulus whose retinal locus is directly observable on a video image of the fundus. Scotoma maps in patients with macular disease and physiologic scotomata associated with normal optic discs are presented. Clinical applications of the method are discussed.

A technique is described of using the video output of the scanning laser ophthalmoscope to monitor the positions of fundus features with respect to an input laser raster. The monitoring performance characteristics are discussed as well as tracking methods and possible applications in psychophysics and laser photocoagulation.

The scanning laser ophthalmoscope (SLO) provides a high-quality television image of the retina using less than 1/1000 of the light required for conventional indirect ophthalmoscopy. The SLO employs a new ophthalmoscopic principle in which a dim laser beam scans across the fundus, and light is collected only from one retinal point at a time. Since the instrument is highly light efficient, illumination levels are comfortable for the patient, and fluorescein angiography can be performed with one tenth of the usual fluorescein dose. Since a continuous, large depth of field view is displayed on the SLO screen and stored on video tape, repeated dynamic inspection of the vitreous, retina and vitreoretinal interface is afforded. In addition, any graphical material that can be displayed on a microcomputer monitor (such as text of video games) can also be impressed on the retinal pattern formed by the sweeping laser beam. The graphical material is thus observed directly by the patient and on the patient's retina by the clinician. Since the exact retinal locus of each point in the graphical material is viewed directly, it is possible to perform perimetry directly on the retina, to measure acuity at arbitrary retinal loci, to study how patients with macular disease use residual functional retina for reading, and to perform distortometry with a retinal (Amsler-type) grid.

This study was conducted to test the efficacy of AIR WISE, an individually administered asthma self-management program. Subjects were paired and randomly assigned to either an experimental group (N = 7) or a control group (N = 7). The frequency of experimental group emergency visits, analyzed over a 12-month posttreatment period, was substantially less than those of the control group, supporting the hypothesis that AIR WISE is effective in high-utilizer children through improved self-management.

We have designed a recording ophthalmoscope which requires substantially less light than conventional ophthalmoscopes or fundus cameras. A laser beam of <100-microW total power provides the flying spot on the subject's retina, allowing an inversion of the usual division of the pupil: only the central half-millimeter is needed for illumination, and the remaining 50 mm(2) are used for light collection. No optical image of the retina is formed, but a photomultiplier tube in a pupillary conjugate plane provides video signals to a TV monitor, where an image appears. A simple analysis explains the gain in sensitivity. Various manipulations of the image are described, some of which are uniquely possible with this system.

Two functional mitochondrial populations with different sedimentation rates (S) were obtained from homogenates of canine myocardium by rate zonal centrifugation using an iso-osmotic Ficoll gradient. To ascertain the origin of these populations, the left ventricular wall of normal myocardium was divided into subepicardial (outer one-third), intermediate (middle on-third), and subendocardial (inner one-third) layers. The slow S mitochondria comprised 75% of the mitochondrial population of the subepicardial layer. In contrast, the fast S mitochondria contributed 65% of the subendocardial population. Intermediate layer mitochondria resembled those of the subepicardium. Mitochondria isolated from the three layers had approximately the same density, as shown by isopycnic zonal centrifugation. These studies indicate that mitochondria from subepicardial and subendocardial layers of normal myocardium differ in size and shape but not in density. Electron micrographs (EM) of the subepicardium showed many mitochondria as long as 4 to 8 sarcomeres. Mitochondria from the outer and inner layers of normal myocardium had the same oxidative phosphorylation parameters. Acute myocardial infarction, lasting 1 or 2 hr, resulted in the selective loss of the fast S mitochondria. Because the fast S mitochondria are prevalent in the subendocardium, these results may explain the greater vulnerability of this layer to anoxia.