Contact lens-related complications in austere conditions among military personnel: a systematic review.

INTRODUCTION: Military service personnel are required to deploy to austere environments where they are exposed to harsh conditions. Many service personnel continue to wear contact lenses when deployed as they are an effective alternative to spectacles by affording superior ergonomic functionality, although they are associated with significant complications. We aimed to explore the prevalence and type of contact lens-related complications among deployed service personnel worldwide. METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. PubMed, Medline, CINAHL and EMBASE databases were searched for relevant articles published between 1950 and 2023. The keywords 'contact lens' and 'military' or 'army' or 'navy' or 'air force' and 'austere' or 'deployed' or 'adverse' were used. RESULTS: Five eligible articles were included. Excluded articles reported contact lens wear in the firm base, were not related to military personnel or did not involve the deployed setting. Major complications associated with contact lens wear included microbial keratitis and contact lens-related discomfort. Excluding case reports, the overall incidence of contact lens-related complications ranged from 0.35% to 25.4%. The three case reports included in this systematic review described Acanthamoeba keratitis, Nocardia keratitis and contact lens-related discomfort as significant complications. These case reports also detailed time to initial presentation and type of contact lens worn when complications were encountered. Types of deployed conditions service personnel were exposed to included desert, temperate and underwater environments. CONCLUSIONS: We highlight a scarcity of recent data regarding contact lens-related complications in the deployed setting. While contact lens-wearing service personnel are at risk of infectious keratitis and contact lens-related discomfort, we recommend good-quality data collection on contact lens wearing schedules and complication rates to steer guidance on contact lens wear in service personnel.

Dynamic ventral disc contraction is necessary for Giardia attachment and host pathology.

Giardia lamblia is a common parasitic protist that infects the small intestine and causes giardiasis, resulting in diarrhea, vomiting, weight loss, and malabsorption. Giardiasis leads to cellular damage, including loss of microvilli, disruption of tight junctions, impaired barrier function, enzyme inhibition, malabsorption, and apoptosis. In the host, motile Giardia trophozoites attach to the duodenal microvilli using a unique microtubule organelle called the ventral disc. Despite early observations of disc-shaped depressions in microvilli after parasite detachment, little is known about disc-mediated attachment mechanisms and there little direct evidence showing that parasite attachment causes cellular damage. However, advancements in in vitro organoid models of infection and genetic tools have opened new possibilities for studying molecular mechanisms of attachment and the impact of attachment on the host. Through high-resolution live imaging and a novel disc mutant, we provide direct evidence for disc contraction during attachment, resolving the long-standing controversy of its existence. Specifically, we identify three types of disc movements that characterize contraction, which in combination result in a decrease in disc diameter and volume. Additionally, we investigate the consequences of attachment and disc contractility using an attachment mutant that has abnormal disc architecture. In a human organoid model, we demonstrate that this mutant has a limited ability to break down the epithelial barrier as compared to wild type. Based on this direct evidence, we propose a model of attachment that incorporates disc contraction to generates the forces required for the observed "grasping" of trophozoites on the host epithelium. Overall, this work highlights the importance of disc contractility in establishing and maintaining parasite attachment, leading to intestinal barrier breakdown.

Touching and feeling: differences in pleasant touch processing between glabrous and hairy skin in humans.

Previous functional magnetic resonance imaging studies in two rare patients, together with microneurography and psychophysical observations in healthy subjects, have demonstrated a system of mechanosensitive C-fiber tactile (CT) afferents sensitive to slowly moving stimuli. They project to the posterior insular cortex and signal pleasant aspects of touch. Importantly, CTs have not been found in the glabrous skin of the hand, yet it is commonly observed that glabrous skin touch is also perceived as pleasant. Here we asked if the brain processing of pleasant touch differs between hairy and glabrous skin by stroking the forearm and glabrous skin of the hand during positron emission tomography. The data showed that, when contrasting slow brush stroking on the forearm with slow brush stroking on the palm, there were significant activations of the posterior insular cortex and mid-anterior orbitofrontal cortex. The opposite contrast showed a significant activation of the somatosensory cortices. Although concurrent psychophysical ratings showed no differences in intensity or pleasantness ratings, a subsequent touch questionnaire in which subjects used a newly developed 'touch perception task' showed significant difference for the two body sites. Emotional descriptors received higher ratings on the forearm and sensory descriptors were rated more highly on the palm. The present findings are consistent with the hypothesis that pleasant touch from hairy skin, mediated by CT afferents, is processed in the limbic-related cortex and represents an innate non-learned process. In contrast, pleasant touch from glabrous skin, mediated by A-beta afferents, is processed in the somatosensory cortex and represents an analytical process dependent on previous tactile experiences.

Fluoroscopically guided percutaneous peritoneal dialysis catheter placement: single center experience and review of the literature.

Experiences with minimally invasive techniques for peritoneal dialysis (PD) catheter placement are being increasingly described. Percutaneous placement of catheters using ultrasound and fluoroscopic guidance has reduced the risk of complications and has led to successful long-term catheter function. An interventional radiology catheter placement capability was established at our facility and it serves as the basis for this report. We performed a retrospective analysis of patients in a tertiary care center in Northern California who required PD between July 2005 and October 2008. Patients underwent PD catheter placement in an interventional radiology suite by the radiologist using a percutaneous Seldinger technique that was guided by fluoroscopy. Sixty-four patients between the ages of 25 and 90 were referred for fluoroscopic PD catheter placement by an interventional radiologist. If clinically indicated, PD was initiated within days of catheter placement. Minor complications were noted: four with minor bleeding, three with catheter migration, and one with temporary exit-site leakage. No bowel or bladder perforations were encountered. Fluoroscopically guided PD catheter placement by interventional radiologists can be a safe and cost-effective strategy to initiate acute or chronic PD. This approach could reduce the need for temporary vascular access and expedite the initiation of PD therapy by eliminating the delays in catheter placement often associated with surgical consultation and operating room scheduling.

Epitopes involved in antibody-mediated protection from Ebola virus.

To determine the ability of antibodies to provide protection from Ebola viruses, monoclonal antibodies (mAbs) to the Ebola glycoprotein were generated and evaluated for efficacy. We identified several protective mAbs directed toward five unique epitopes on Ebola glycoprotein. One of the epitopes is conserved among all Ebola viruses that are known to be pathogenic for humans. Some protective mAbs were also effective therapeutically when administered to mice 2 days after exposure to lethal Ebola virus. The identification of protective mAbs has important implications for developing vaccines and therapies for Ebola virus.

Circular dichroism reveals sensitivity of glucagon solution structure to fluoroalcohols, pH and ionic strength.

Circular dichroism reports that glucagon in solution becomes increasingly helical with the addition of fluoroalcohol (which also decreases solution pH), and with changes in pH and ionic strength. Given the variability of structure observed, these data indicate that care must be taken when comparing results obtained under different solution conditions.

A comparison of outcomes after indocyanine green and trypan blue assisted internal limiting membrane peeling during macular hole surgery.

AIMS: To compare the anatomical and visual outcomes of macular hole repair surgery using indocyanine green (ICG) or trypan blue (TB) staining of the internal limiting membrane (ILM). METHOD: Retrospective analysis of 37 eyes from 37 consecutive patients with stage 2, 3, and 4 idiopathic macular holes who underwent macular hole repair by one surgeon using the same technique but utilising different dyes for ILM peeling. In 19 patients ICG was used while 18 patients had TB. The anatomical and visual results in these two groups were compared. RESULTS: There were no significant differences in the demographic and macular hole characteristics of the ICG and TB groups. Macular hole closure was achieved in 91.9% of all patients of which the ICG group had an 89.5% hole closure rate and the TB group had a 94.4% hole closure rate. After excluding cases with failed hole closure and other vision affecting complications, there was no significant difference between the preoperative visual acuities in the TB and ICG groups but the postoperative visual acuities were better in the TB than the ICG group (p = 0.036). The TB group also had more Snellen lines of improvement than the ICG group (2.94 v 1.79 lines; p = 0.046). CONCLUSION: TB appears to be less toxic than ICG when used in dye assisted peeling of ILM during macular hole repair as reflected by the better visual results in the TB group of patients.

Down-regulation but not phosphorylation of stathmin is associated with induction of HL60 cell growth arrest and differentiation by physiological agents.

Stathmin is a cytosolic phosphoprotein that has an important but, as yet, undefined role in cell proliferation and differentiation. Induction of growth arrest and differentiation of HL60 cells to monocytes by phorbol 12-myristate 13-acetate is associated with rapid phosphorylation of the protein. Stathmin phosphorylation was not seen when HL60 cells were induced to differentiate to monocytes, by 1 alpha, 25-dihydroxyvitamin D3, and to neutrophils, by all-trans retinoic acid and granulocyte colony stimulating factor. In all the above instances, stathmin expression was down-regulated. Thus, increased stathmin phosphorylation is not required for cell growth arrest or differentiation or down-regulation of stathmin expression.

Isospora belli enteritis in three homosexual men.

Isospora belli is an uncommon cause of diarrhea in man. Like the closely related Cryptosporidium, the organism causes disease that may be more severe and chronic in patients with underlying immune deficiency states. We describe three male homosexuals with Isospora enteritis. Each had several months of diarrhea. All three patients had lymphopenia and two had profound T cell helper-suppressor ratio reversal. In addition, two of the patients admitted to oral-anal contact, a practice associated with the acquisition of parasites and other enteric pathogens in the homosexual population. We suggest that Isospora belli may be a sexually transmitted pathogen which should be considered in the diagnosis of homosexual patients with diarrhea.

The role of auditory cues in modulating the perception of electric toothbrushes.

Recent research shows that what people hear can influence what they feel. We investigated whether the perception of an electric toothbrush might also be affected by the sound that it makes. Participants were required to make stereotypical brushing movements with a standard electric toothbrush while they rated either the pleasantness or the roughness of the vibrotactile stimulation they felt on their teeth. The results demonstrate that the perception of the sensations experienced during toothbrush use were systematically altered by variations in the auditory feedback elicited by the brushing action. Participants reported that the toothbrush felt more pleasant and less rough when either the overall sound level was reduced, or when just the high-frequency sounds were attenuated. These results highlight the significant role that auditory cues can play in modulating the perception and evaluation of everyday products in use, and provide a paradigm for future study in this area.

Production and characterization of monoclonal antibodies against Naja naja atra cobrotoxin.

Twelve monoclonal antibodies against cobrotoxin from Naja naja atra venom were tested for cross-reactivity with eight different snake toxins, binding to linear epitopes, prevention of cobrotoxin binding to acetylcholine receptor (AchR) in vitro, and protection in mice concomitantly given a lethal dose of cobrotoxin. The antibodies were highly specific, as evidenced by little reactivity with other snake toxins. None of the monoclonal antibodies bound to reduced cobrotoxin or synthesized 8-mer regions spanning the whole molecule, thus suggesting the recognition of conformational epitopes. The in vitro binding of toxin to AchR was competitively inhibited (23-79%) with a 1.66:1 mole ratio of antibody:AchR. Preincubation of monoclonal antibody with toxin before adding AchR (3:1 mole ratio of AchR:antibody) inhibited the in vitro binding of toxin to AchR by 20-80%. Monoclonal antibodies added after the preincubation of toxin with AchR did not dissociate the toxin-AchR complex. An antibody:toxin mole ratio of 2.5:1, with 6 micrograms of cobrotoxin, delayed the time to death of mice 3.7-23.8-fold over control mice. The monoclonal antibodies that most effectively prevented in vitro binding of toxin to AchR also provided the longest delay in time to death in mice.

The structure of colour naming space.

An experiment is described which replicates recent name mapping work, and delves further into the detailed structure of colour naming space. Observers freely named 1044 CRT-displayed colour-background combinations, sampled regularly along the (u',v') axes of the 1976 UCS, and along a luminance axis. Three response measures - response times, confidence ratings and consistencies - were obtained. These measures were collapsed by principal components analysis (PCA) into 'nameability', a single measure of ease of naming of colours. The structure of colour naming space and the use of different colour name types, were investigated. Data confirmed the uniqueness of basic colour terms as compared with the non-basic terms, agreeing with previous constrained naming studies. Colour naming space was found to exhibit regular structure, which appears to be linked to fundamental response categories, and to previous observations that colour naming space may be divided into five major regions.

Assessment of the effect of oral clarithromycin on visual outcome following presumed bacterial endophthalmitis.

PURPOSE: The use of clarithromycin was assessed as a biofilm reducing agent in the management of bacterial endophthalmitis. METHODS: 84 eyes of 83 patients presenting with clinical signs highly suggestive of bacterial endophthalmitis were treated using a standard regimen of intraocular vancomycin, amikacin and systemic steroids, which in addition included oral clarithromycin. Ocular penetration of oral clarithromycin in healthy and inflamed eyes was also assessed. RESULTS: Comparing visual acuities at presentation and 6 months, 66% of patients demonstrated an improvement. Intraocular samples were culture positive in 58% of eyes. As compared to culture positive cases, more culture negative cases achieved a visual acuity of 6/12 or better (p = 0.0047). As compared to patients receiving the standard protocol but without clarithromycin, a greater number of culture negative cases demonstrated an improvement in vision of > or = + 6 Snellen lines (p = 0.023). The ocular penetration of clarithromycin into the anterior chamber of inflamed eyes appears sufficient to allow anti-biofilm activity against bacteria at the basic pH encountered in eyes with endophthalmitis. CONCLUSIONS: The ocular penetration of clarithromycin appears adequate for anti-biofilm activity in inflamed eyes. The beneficial effects of oral clarithromycin on visual outcome has been demonstrated in culture negative eyes with clinical signs highly suggestive of bacterial endophthalmitis. The final visual outcome for culture positive cases remains poor.

Signal transduction via G-protein-linked receptors: physiological regulation from the plasma membrane to the genome.

Many neurotransmitters, hormones, and drugs express their actions through binding to cell-surface receptors that are coupled to membrane-localized effectors via GTP-binding regulatory proteins (G-proteins). Muscarinic acetylcholine, alpha- and beta-adrenergic receptors are members of this populous class of G-protein-linked receptors. Adenylyl cyclase, phospholipase C, and ion channel activities are examples of effectors regulated via these receptors. Signal transduction via G-protein-linked receptors can be regulated at the level of the receptor, G-protein(s), and effector(s). Activation of G-protein-mediated pathway propagates the signal and leads to desensitization (short-term adaptation) and then down-regulation (long-term adaptation). How transmembrane signaling is linked to expression at the level of the gene (transcriptional control), at the level of mRNA (post-transcriptional control) and at the level of the protein (post-translational modification) remains a central question of neurobiology. Investigations at each of these potential loci for regulation have begun to reveal the molecular basis for down-regulation by agonist, up-regulation by permissive hormones (like adrenal steroids), and cross-regulation among G-protein-mediated pathways. The general topic will be discussed drawing upon recent studies of the regulation of the adrenergic receptor family (alpha- and beta-). These recent advances provide a focus for a broader understanding of the integration of information between the genome and transmembrane signaling.

Emigration stress and language proficiency as correlates of depression in a sample of Southeast Asian refugees.

This research evaluated a stress management, coping skills model of adjustment in the analysis of depression in a sample of Laotian refugees living in the southeastern United States. Stressful events and experiences during emigration and a lack of English proficiency were associated with depressive symptoms, while demographic variables and social support were not. English proficiency also significantly reduced the impact of acculturative stressors on depression, suggesting that language skill may act as a stress buffer in the new cultural environment.

Chronic hepatitis: a retrospective study in 34 dogs.

The aims of this study were to characterize the histological changes observed in 34 accessioned cases of canine chronic hepatitis and to correlate these changes with the clinical pathological data. Cases of chronic hepatitis were subdivided into 6 categories: chronic active hepatitis (10/34), chronic persistent hepatitis (7/32), chronic cholestatic hepatitis (6/34), fibrosing hepatitis with cirrhosis (3/34), chronic cholangiohepatitis (3/34), and miscellaneous secondary hepatitis (5/34). Iron accumulation was a consistent finding in all livers examined. Although all cases of chronic hepatitis had elevated liver enzymes, no correlation was detected between biochemical parameters and the severity of morphologic changes. Similarly, no correlation was detected between rhodanine staining for copper and morphologic or biochemical indicators of cholestasis. However, presence of copper correlated well with reticulo-fibrosis (r = 0.8) and bile duct hyperplasia, suggesting that changes in the hemodynamics of the hepatic acini due to fibrosis could influence storage of copper.

Symmetry-extended counting rules for periodic frameworks.

A symmetry-adapted version of the Maxwell rule appropriate to periodic bar-and-joint frameworks is obtained, and is further extended to body-and-joint systems. The treatment deals with bodies and forces that are replicated in every unit cell, and uses the point group isomorphic to the factor group of the space group of the framework. Explicit expressions are found for the numbers and symmetries of detectable mechanisms and states of self-stress in terms of the numbers and symmetries of framework components. This approach allows detection and characterization of mechanisms and states of self-stress in microscopic and macroscopic materials and meta-materials. Illustrative examples are described. The notion of local isostaticity of periodic frameworks is extended to include point-group symmetry.

Breastfeeding success rate after vaginal delivery can be high despite the use of epidural fentanyl: an observational cohort study.

BACKGROUND: Epidural labor analgesia inclusive of high-dose fentanyl has been thought to affect breastfeeding in multiparous patients. In our experience, this effect is not as significant as quoted in the literature. This study was designed to evaluate breastfeeding success in women receiving epidural analgesia with fentanyl-containing solutions at our institution. METHODS: Term multiparous women who received epidural analgesia for labor, had previously breastfed, and who intended to breastfeed, were recruited. Baseline demographics, as well as detailed epidural, obstetric and neonatal data, were collected. Epidural analgesia was achieved with a mixture of bupivacaine and fentanyl. Subjects were telephoned both 1 and 6 weeks after delivery, and a breastfeeding questionnaire was completed. Our primary outcome was breastfeeding cessation at 6 weeks. RESULTS: One hundred and five women were recruited, with 18 exclusions. The median cumulative epidural fentanyl dose was 151.4 microg (30-570 microg). No neonates developed complications attributable to labor analgesia. Four women stopped breastfeeding because of issues related to the baby (4.6%); only one of them received a fentanyl dose >150 microg. The breastfeeding success rate was therefore >95%. The women had a median maternity leave of 12 months, and 69% received post-partum lactation support. CONCLUSIONS: The incidence of successful breastfeeding in multiparous women who undergo vaginal delivery with epidural analgesia inclusive of fentanyl is much greater at our institution than previously reported in the literature. This may be due to favorable conditions such as time off work and post-natal support.