Confocal reflectance microscopy for mapping collagen fiber organization in the vitreous gel of the eye

Vitreous collagen structure plays an important role in ocular mechanics. However, capturing this structure with existing vitreous imaging methods is hindered by the loss of sample position and orientation, low resolution, or a small field of view. The objective of this study was to evaluate confocal reflectance microscopy as a solution to these limitations. Intrinsic reflectance avoids staining, and optical sectioning eliminates the requirement for thin sectioning, minimizing processing for optimal preservation of the natural structure. We developed a sample preparation and imaging strategy using ex vivo grossly sectioned porcine eyes. Imaging revealed a network of uniform diameter crossing fibers (1.1 ± 0.3 µm for a typical image) with generally poor alignment (alignment coefficient = 0.40 ± 0.21 for a typical image). To test the utility of our approach for detecting differences in fiber spatial distribution, we imaged eyes every 1 mm along an anterior-posterior axis originating at the limbus and quantified the number of fibers in each image. Fiber density was higher anteriorly near the vitreous base, regardless of the imaging plane. These data demonstrate that confocal reflectance microscopy addresses the previously unmet need for a robust, micron-scale technique to map features of collagen networks in situ across the vitreous.

Structure and mechanics of the vitreoretinal interface

Vitreoretinal mechanics plays an important role in retinal trauma and many sight-threatening diseases. In age-related pathologies, such as posterior vitreous detachment and vitreomacular traction, lingering vitreoretinal adhesions can lead to macular holes, epiretinal membranes, retinal tears and detachment. In age-related macular degeneration, vitreoretinal traction has been implicated in the acceleration of the disease due to the stimulation of vascular growth factors. Despite this strong mechanobiological influence on trauma and disease in the eye, fundamental understanding of the mechanics at the vitreoretinal interface is limited. Clarification of adhesion mechanisms and the role of vitreoretinal mechanics in healthy eyes and disease is necessary to develop innovative treatments for these pathologies. In this review, we evaluate the existing literature on the structure and function of the vitreoretinal interface to gain insight into age- and region-dependent mechanisms of vitreoretinal adhesion. We explore the role of vitreoretinal adhesion in ocular pathologies to identify knowledge gaps and future research areas. Finally, we recommend future mechanics-based studies to address the critical needs in the field, increase fundamental understanding of vitreoretinal mechanisms and disease, and inform disease treatments.

Risk factors for transmission of carbapenem-resistant Enterobacterales to healthcare personnel gloves and gowns in the USA

BACKGROUND

Hospitals are sources for acquisition of carbapenem-resistant Entero-bacterales (CRE), and it is believed that the contamination of healthcare personnel (HCP) hands and clothing play a major role in patient-to-patient transmission of antibiotic-resistant bacteria.

AIM

The aim of this study was to determine which HCP types, HCP-patient interactions, and patient characteristics are associated with greater transmission of CRE to HCP gloves and gowns in the hospital.

METHODS

This was a prospective observational cohort study that enrolled patients with recent surveillance or clinical cultures positive for CRE at five hospitals in four states in the USA. HCP gloves and gown were cultured after patient care. Samples were also obtained from patients' stool, perianal area, and skin of the chest and arm to assess bacterial burden.

FINDINGS

Among 313 CRE-colonized patients and 3070 glove and gown cultures obtained after patient care, HCP gloves and gowns were found to be contaminated with CRE 7.9% and 4.3% of the time, respectively. Contamination of either gloves or gowns occurred in 10.0% of interactions. Contamination was highest (15.3%) among respiratory therapists (odds ratio: 3.79; 95% confidence interval: 1.61-8.94) and when any HCP touched the patient (1.52; 1.10-2.12). Associations were also found between CRE transmission to HCP gloves or gown and: being in the intensive care unit, having a positive clinical culture, and increasing bacterial burden on the patient.

CONCLUSION

CRE transmission to HCP gloves and gown occurred frequently. These findings may inform evidence-based policies about what situations and for which patients contact precautions are most important.

Genetic Epidemiologic Analysis of Hypertensive Retinopathy in an Underrepresented and Rare Federally Recognized Native American Population of the Intermountain West

Understanding disease risk is challenging in multifactorial conditions as it can differ by environment, ethnicity and race. The Confederated Tribes of the Goshute Reservation are one of the most isolated populations in the United States. Retinal changes are a reliable indicator for systemic disease. We conducted a cross-sectional study to identify correlations between genetic data and epidemiological risk factors for blinding retinal disease in this tribe. As part of the "Supporting Prediction and Prevention Blindness Project (SPBPP)" in the Native American Population of the Intermountain West, we found that hypertensive retinopathy was the most prevalent retinal disease. We found that forty-two percent of the Goshute population was affected. Blood samples, fundus photos and intraocular pressure were obtained for all participants. In addition, a standardized questionnaire was administered. DNA and total cholesterol, HDL, LDL, VLDL, triglycerides and HbA1c were also evaluated. Our study interrogated genetic variants from the PAGE study (ARMS2 rs10490924, CFH rs800292, rs1061170) and additional studies that looked at previously associated genetic variants with retinal disease associated with cardiovascular disease. We conducted univariate and multivariate logistic regression in Stata v15.0. We found an association between hypertriglyceridemia and HTR (adjp = .05) within the Goshute population. To the best of our knowledge, this is the first study to demonstrate the prevalence of hypertensive retinopathy in a Native American population. Moreover, our study is the first to demonstrate an independently predictive relationship between hypertriglyceridemia and hypertensive retinopathy in an American Indian population. This study furthers our knowledge about prevalent blinding eye disease within the most geographically isolated federally recognized native United States American tribe, for which nothing has been published with respect to any disease. Although, this study furthers our understanding about the prevalence of genetic epidemiological risk factors within this population, it has greater implications for the screening of blinding diseases in underserved populations in general. This study can inform public health on planning and delivering of quality, accessible and relevant care to this population.

Progressive optic nerve changes in cavitary optic disc anomaly: integration of copy number alteration and cis-expression quantitative trait loci to assess disease etiology

Background

We performed clinical and genetic characterization of a family with cavitary optic disc anomaly (CODA), an autosomal dominant condition that causes vision loss due to adult-onset maculopathy in the majority of cases. CODA is characterized by a variably excavated optic nerve appearance such as morning glory, optic pit, atypical coloboma, and severe optic nerve cupping.

Methods

Four affected and fourteen unaffected family members of a multi-generation pedigree were phenotyped by visual acuity, intraocular pressure, dilated fundus examination, fundus photography, and optical coherence tomography. Genetic analysis was performed by breakpoint polymerase chain reaction (PCR), long range PCR, and direct Sanger sequencing. The functional relevance of the copy number alteration region was assessed by in silico analysis.

Results

We found progressive optic nerve cupping in three affected members of a family with CODA. In one individual, an optic pit developed over time from a normal optic nerve. By two independent methods, we detected a previously described intergenic triplication that segregated with disease in all adults of the family. The copy number alteration was also detected in five children with normal optic nerves. eQTL analysis demonstrated that this CNA region regulates expression of up to 4 genes in cis.

Conclusions

Morning glory, optic pit and atypical coloboma are currently considered congenital anomalies of the optic nerve, but our data indicate that in CODA, the excavated optic nerve appearance may develop after birth and into adulthood. In silico analysis of the CNA, may explain why vairable expressivity is observed in CODA.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0800-4) contains supplementary material, which is available to authorized users.

ALPK1 missense pathogenic variant in five families leads to ROSAH syndrome, an ocular multisystem autosomal dominant disorder

Purpose

To identify the molecular cause in five unrelated families with a distinct autosomal dominant ocular systemic disorder we called ROSAH syndrome due to clinical features of retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and migraine headache.

Methods

Independent discovery exome and genome sequencing in families 1, 2, and 3, and confirmation in families 4 and 5. Expression of wild-type messenger RNA and protein in human and mouse tissues and cell lines. Ciliary assays in fibroblasts from affected and unaffected family members.

Results

We found the heterozygous missense variant in the ɑ-kinase gene, ALPK1, (c.710C>T, [p.Thr237Met]), segregated with disease in all five families. All patients shared the ROSAH phenotype with additional low-grade ocular inflammation, pancytopenia, recurrent infections, and mild renal impairment in some. ALPK1 was notably expressed in retina, retinal pigment epithelium, and optic nerve, with immunofluorescence indicating localization to the basal body of the connecting cilium of the photoreceptors, and presence in the sweat glands. Immunocytofluorescence revealed expression at the centrioles and spindle poles during metaphase, and at the base of the primary cilium. Affected family member fibroblasts demonstrated defective ciliogenesis.

Conclusion

Heterozygosity for ALPK1, p.Thr237Met leads to ROSAH syndrome, an autosomal dominant ocular systemic disorder.

The Utah Protocol for Postmortem Eye Phenotyping and Molecular Biochemical Analysis

Purpose

Current understanding of local disease pathophysiology in AMD is limited. Analysis of the human disease-affected tissue is most informative, as gene expression, expressed quantitative trait loci, microenvironmental, and epigenetic changes can be tissue, cell type, and location specific. Development of a novel translational treatment and prevention strategies particularly for earlier forms of AMD are needed, although access to human ocular tissue analysis is challenging. We present a standardized protocol to study rapidly processed postmortem donor eyes for molecular biochemical and genomic studies.

Methods

We partnered with the Utah Lions Eye Bank to obtain donor human eyes, blood, and vitreous, within 6 hours postmortem. Phenotypic analysis was performed using spectral-domain optical coherence tomography (SD-OCT) and color fundus photography. Macular and extramacular tissues were immediately isolated, and the neural retina and retinal pigment epithelium/choroid from each specimen were separated and preserved. Ocular disease phenotype was analyzed using clinically relevant grading criteria by a group of four ophthalmologists incorporating data from SD-OCT retinal images, fundus photographs, and medical records.

Results

The use of multimodal imaging leads to greater resolution of retinal pathology, allowing greater phenotypic rigor for both interobserver phenotype and known clinical diagnoses. Further, our analysis resulted in excellent quality RNA, which demonstrated appropriate tissue segregation.

Conclusions

The Utah protocol is a standardized methodology for analysis of disease mechanisms in AMD. It uniquely allows for simultaneous rigorous phenotypic, molecular biochemical, and genomic analysis of both systemic and local tissues. This better enables the development of disease biomarkers and therapeutic interventions.

Adverse outcomes after planned surgery with anticipated intensive care admission in out-of-office-hours time periods: a multicentre cohort study

BACKGROUND

Increasing mortality for patients admitted to hospitals during the weekend is a contentious but well described phenomenon. However, it remains uncertain whether adverse outcomes, including prolonged hospital length-of-stay (LOS), may also occur after patients undergoing major planned surgery are admitted to an intensive care unit (ICU) out-of-office-hours, either during weeknights (after 18:00) or on weekends.

METHODS

All planned surgical admissions requiring admission to one of 183 ICUs across Australia and New Zealand between 2006 and 2016 were included in this retrospective population-based cohort study. Primary outcomes were hospital LOS and hospital mortality.

RESULTS

Of the total 504 713 planned postoperative ICU admissions, 33.6% occurred during out-of-office-hours. After adjusting for available risk factors, out-of-office-hours ICU admissions were associated with a significant increase in hospital LOS [+2.6 days, 95% confidence interval (CI) 2.5-2.6], mortality [odd ratio (OR) 1.5, 95%CI 1.4-1.6], and a reduced chance of being directly discharged home (OR 0.8, 95%CI 0.8-0.8). The strongest association for adverse outcomes occurred with weekend ICU admissions (hospital LOS: +3.0 days, 95%CI 3.2-3.6; hospital mortality: OR 1.7, 95%CI 1.6-1.8). Clustering of adverse outcomes by hospitals was not observed in the generalised estimating equation analyses.

CONCLUSIONS

Despite a greater clinical staff availability and higher monitoring levels, planned surgery requiring anticipated out-of-office-hours ICU admission was associated with a prolonged hospital LOS, reduced discharge directly home, and increased mortality compared with in-office-hours admissions. Our findings have potential clinical, economic and health policy implications on how complex planned surgery should be planned and managed.

Genetics of age-related macular degeneration (AMD)

Age-related macular degeneration (AMD) is a progressive blinding disease and represents the leading cause of visual impairment in the aging population. AMD affects central vision which impairs one's ability to drive, read and recognize faces. There is no cure for this disease and current treatment modalities for the exudative form of the disease require repeated intravitreal injections which may be painful, are incompletely efficacious, and represent a significant treatment burden for both the patient and physician. As such, AMD represents a significant and important clinical problem.It is anticipated that in three years' time, 196 million individuals will be affected with AMD. Over 250 billion dollars per year are spent on care for AMD patients in the US. Over half of the heritability is explained by two major loci, thus AMD is considered the most well genetically defined of the complex disorders. A recent GWAS on 43,566 subjects identified novel loci and pathways associated with AMD risk, which has provided an excellent platform for additional functional studies. Genetic variants have been investigated, particularly with respect to anti-VEGF treatment, however to date, no pharmacogenomic associations have been consistently identified across these studies. It may be that if the goal of personalized medicine is to be realized and biomarkers are to have predictive value for determining the magnitude of risk for AMD at the genetic level, one will need to examine the relationships between these pathways across disease state and relative to modifiable risk factors such as hypertension, smoking, body mass index, and hypercholesterolemia. Further studies investigating protective alleles in populations with low AMD prevalence may lead to this goal.

Deconstructing the relative benefits of a universal glove and gown intervention on MRSA acquisition

BACKGROUND

The 20-site Benefits of Universal Glove and Gown (BUGG) study found that wearing gloves and gowns for all patient contacts in the intensive care unit (ICU) reduced acquisition rates of meticillin-resistant Staphylococcus aureus (MRSA). The relative importance of gloves and gowns as a barrier, improved hand hygiene, and reduced healthcare worker (HCW)-patient contact rates is unknown.

AIM

To determine what proportion of the reduction in acquisition rates observed in the BUGG study was due to improved hand hygiene, reduced contact rates, and universal glove and gown use using agent-based simulation modelling.

METHODS

An existing agent-based model to simulate MRSA transmission dynamics in an ICU was modified, and the model was calibrated using site-specific data. Model validation was completed using data collected in the BUGG study. A full 2^k factorial design was conducted to quantify the relative benefits of improving each of the aforementioned factors with respect to MRSA acquisition rates.

FINDINGS

Across 40 simulated replications for each factorial design point and intervention site, approximately 44% of the decrease in MRSA acquisition rates was due to universal glove and gown use, 38.1% of the decrease was due to improvement in hand hygiene compliance on exiting patient rooms, and 14.5% of the decrease was due to the reduction in HCW-patient contact rates.

CONCLUSION

Using mathematical modelling, the decrease in MRSA acquisition in the BUGG study was found to be due primarily to the barrier effects of gowns and gloves, followed by improved hand hygiene and lower HCW-patient contact rates.

Ancestry of the Timorese: age-related macular degeneration associated genotype and allele sharing among human populations from throughout the world

We observed that the third leading cause of blindness in the world, age-related macular degeneration (AMD), occurs at a very low documented frequency in a population-based cohort from Timor-Leste. Thus, we determined a complete catalog of the ancestry of the Timorese by analysis of whole exome chip data and haplogroup analysis of SNP genotypes determined by sequencing the Hypervariable I and II regions of the mitochondrial genome and 17 genotyped YSTR markers obtained from 535 individuals. We genotyped 20 previously reported AMD-associated SNPs in the Timorese to examine their allele frequencies compared to and between previously documented AMD cohorts of varying ethnicities. For those without AMD (average age > 55 years), genotype and allele frequencies were similar for most SNPs with a few exceptions. The major risk allele of HTRA1 rs11200638 (10q26) was at a significantly higher frequency in the Timorese, as well as 3 of the 5 protective CFH (1q32) SNPs (rs800292, rs2284664, and rs12066959). Additionally, the most commonly associated AMD-risk SNP, CFH rs1061170 (Y402H), was also seen at a much lower frequency in the Korean and Timorese populations than in the assessed Caucasian populations (C ~7 vs. ~40%, respectively). The difference in allele frequencies between the Timorese population and the other genotyped populations, along with the haplogroup analysis, also highlight the genetic diversity of the Timorese. Specifically, the most common ancestry groupings were Oceanic (Melanesian and Papuan) and Eastern Asian (specifically Han Chinese). The low prevalence of AMD in the Timorese population (2 of 535 randomly selected participants) may be due to the enrichment of protective alleles in this population at the 1q32 locus.

Differential Gene Expression in Age-Related Macular Degeneration

Gene expression is the first step in ascribing function between an associated gene and disease. Understanding how variation in a gene influences expression, particularly in tissues affected by the disease, may help elucidate what influences the phenotypic outcome of that disease. Previous studies of the genetics of age-related macular degeneration (AMD) have identified several risk factors, but have not yet bridged the gap between gene association and identifying a specific mechanism or function that is involved in the pathogenesis of AMD. Advances in genomic technologies, such as RNA sequencing (RNA-seq), single cell RNA-seq, bilsulfite sequencing, and/or whole genome methylation, will be powerful tools for identifying genes/pathways that are differentially expressed in those with AMD versus those without AMD. These technologies should advance the field of AMD research so that appropriate preventive and therapeutic targets can be developed.

Predictors of early treatment discontinuation in a cohort of patients treated with boceprevir-based therapy for hepatitis C infection

In this real-world cohort, 49% of patients stopped boceprevir-based hepatitis C therapy early, with only 20% stopping due to treatment futility. Having more comorbidities was significantly associated with early discontinuation. Tolerability of boceprevir-based regimens may be substantially worse than reported in clinical trials, particularly for patients with comorbidities.

Rare and common variants in extracellular matrix gene Fibrillin 2 (FBN2) are associated with macular degeneration

Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10(-5)). Thus, it appears that rare and common variants in a single gene--FBN2--can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.

FLT1 genetic variation predisposes to neovascular AMD in ethnically diverse populations and alters systemic FLT1 expression

PURPOSE

Current understanding of the genetic risk factors for age-related macular degeneration (AMD) is not sufficiently predictive of the clinical course. The VEGF pathway is a key therapeutic target for treatment of neovascular AMD; however, risk attributable to genetic variation within pathway genes is unclear. We sought to identify single nucleotide polymorphisms (SNPs) associated with AMD within the VEGF pathway.

METHODS

Using a tagSNP, direct sequencing and meta-analysis approach within four ethnically diverse cohorts, we identified genetic risk present in FLT1, though not within other VEGF pathway genes KDR, VEGFA, or VASH1. We used ChIP and ELISA in functional analysis.

RESULTS

The FLT1 SNPs rs9943922, rs9508034, rs2281827, rs7324510, and rs9513115 were significantly associated with increased risk of neovascular AMD. Each association was more significant after meta-analysis than in any one of the four cohorts. All associations were novel, within noncoding regions of FLT1 that do not tag for coding variants in linkage disequilibrium. Analysis of soluble FLT1 demonstrated higher expression in unaffected individuals homozygous for the FLT1 risk alleles rs9943922 (P = 0.0086) and rs7324510 (P = 0.0057). In silico analysis suggests that these variants change predicted splice sites and RNA secondary structure, and have been identified in other neovascular pathologies. These data were supported further by murine chromatin immunoprecipitation demonstrating that FLT1 is a target of Nr2e3, a nuclear receptor gene implicated in regulating an AMD pathway.

CONCLUSIONS

Although exact variant functions are not known, these data demonstrate relevancy across ethnically diverse genetic backgrounds within our study and, therefore, hold potential for global efficacy.

Patient factors associated with frequent clotting of dialysers during haemodiafiltration in critically ill patients: a post hoc analysis of a randomised controlled study

Continuous haemodiafiltration (CVVHDF) is the main form of renal replacement therapy in critically ill patients with severe acute kidney injury. Clotting of the dialysers during CVVHDF is frequent, because most patients with acute kidney injury have an increased risk of bleeding and cannot be systemically anticoagulated. Using data from a randomised controlled trial comparing the efficiency of CVVHDF by placing the dialysis catheter tip at the right atrium or superior vena cava, this study assessed the patient factors associated with an increased risk of frequent clotting of the dialysers-defined by >1 dialysers clotted per day of CVVHDF. Of the 94 patients included in this study, a higher body mass index, a higher platelet count and a lower International Normalized Ratio were associated with an increased risk of frequent clotting of dialysers in the univariate analyses. Use of aspirin or clopidogrel, causes of acute kidney injury and daily dose of unfractionated heparin used were not significantly associated with the risk of frequent clotting of dialysers. In the multivariate parsimony model, only a high body mass index (odds ratio 1.06 per point increment, 95% confidence interval 1.01 to 1.13; P=0.036) and a high platelet count (odds ratio 1.84 per 100x10(9)/l increment, 95% confidence interval 1.17 to 2.91; P=0.009), both in a relatively linear fashion, were independently associated with an increased risk of frequent clotting of dialysers. Optimising the position of the tip of the dialysis catheter may be particularly important for patients with a high body mass index and platelet count in order to reduce frequent clotting of dialysers during CVVHDF.

Encapsulation of Au Nanoparticles on a Silicon Wafer During Thermal Oxidation

We report the behavior of Au nanoparticles anchored onto a Si(111) substrate and the evolution of the combined structure with annealing and oxidation. Au nanoparticles, formed by annealing a Au film, appear to "float" upon a growing layer of SiO₂ during oxidation at high temperature, yet they also tend to become partially encapsulated by the growing silica layers. It is proposed that this occurs largely because of the differential growth rates of the silica layer on the silicon substrate between the particles and below the particles due to limited access of oxygen to the latter. This in turn is due to a combination of blockage of oxygen adsorption by the Au and limited oxygen diffusion under the gold. We think that such behavior is likely to be seen for other metal-semiconductor systems.

Seven new loci associated with age-related macular degeneration

Age-related macular degeneration (AMD) is a common cause of blindness in older individuals. To accelerate the understanding of AMD biology and help design new therapies, we executed a collaborative genome-wide association study, including >17,100 advanced AMD cases and >60,000 controls of European and Asian ancestry. We identified 19 loci associated at P < 5 × 10(-8). These loci show enrichment for genes involved in the regulation of complement activity, lipid metabolism, extracellular matrix remodeling and angiogenesis. Our results include seven loci with associations reaching P < 5 × 10(-8) for the first time, near the genes COL8A1-FILIP1L, IER3-DDR1, SLC16A8, TGFBR1, RAD51B, ADAMTS9 and B3GALTL. A genetic risk score combining SNP genotypes from all loci showed similar ability to distinguish cases and controls in all samples examined. Our findings provide new directions for biological, genetic and therapeutic studies of AMD.

Influence of ROBO1 and RORA on risk of age-related macular degeneration reveals genetically distinct phenotypes in disease pathophysiology

ROBO1 is a strong candidate gene for age-related macular degeneration (AMD) based upon its location under a linkage peak on chromosome 3p12, its expression pattern, and its purported function in a pathway that includes RORA, a gene previously associated with risk for neovascular AMD. Previously, we observed that expression of ROBO1 and RORA is down-regulated among wet AMD cases, as compared to their unaffected siblings. Thus, we hypothesized that contribution of association signals in ROBO1, and interaction between these two genes may be important for both wet and dry AMD. We evaluated association of 19 single nucleotide polymorphisms (SNPs) in ROBO1 with wet and dry stages of AMD in a sibling cohort and a Greek case-control cohort containing 491 wet AMD cases, 174 dry AMD cases and 411 controls. Association signals and interaction results were replicated in an independent prospective cohort (1070 controls, 164 wet AMD cases, 293 dry AMD cases). The most significantly associated ROBO1 SNPs were rs1387665 under an additive model (meta P = 0.028) for wet AMD and rs9309833 under a recessive model (meta P = 6 × 10(-4)) for dry AMD. Further analyses revealed interaction between ROBO1 rs9309833 and RORA rs8034864 for both wet and dry AMD (interaction P<0.05). These studies were further supported by whole transcriptome expression profile studies from 66 human donor eyes and chromatin immunoprecipitation assays from mouse retinas. These findings suggest that distinct ROBO1 variants may influence the risk of wet and dry AMD, and the effects of ROBO1 on AMD risk may be modulated by RORA variants.

Do contact precautions cause depression? A two-year study at a tertiary care medical centre

Contact precautions, used to reduce the transmission of infectious diseases, include the wearing of gowns and gloves for room entry. Previous small studies have shown an association between contact precautions and increased symptoms of depression and anxiety. A retrospective cohort of all patients admitted to a tertiary care centre over two years was studied to assess the relationship between contact precautions and depression or anxiety. During the two-year period, there were 70,275 admissions including 28,564 unique non-intensive-care-unit (ICU), non-psychiatric admissions. After adjusting for potential confounders, contact precautions were associated with depression [odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2-1.5] but not with anxiety (OR 0.8, 95% CI 0.7-1.1) in the non-ICU population. Depression was 40% more prevalent among general inpatients on contact precautions.

Efficacy of UV light treatment for the microbiological decontamination of chicken, associated packaging, and contact surfaces

UV light was investigated for the decontamination of raw chicken, associated packaging, and contact surfaces. The UV susceptibilities of a number of Campylobacter isolates (seven Campylobacter jejuni isolates and three Campylobacter coli isolates), Escherichia coli ATCC 25922, and Salmonella enterica serovar Enteritidis ATCC 10376 in liquid media were also investigated. From an initial level of 7 log CFU/ml, no viable Campylobacter cells were detected following exposure to the most intense UV dose (0.192 J/cm(2)) in liquid media (skim milk subjected to ultrahigh-temperature treatment and diluted 1:4 with maximum recovery diluent). Maximum reductions of 4.8 and 6.2 log CFU/ml were achieved for E. coli and serovar Enteritidis, respectively, in liquid media. Considerable differences in susceptibilities were found between the Campylobacter isolates examined, with variations of up to 4 log CFU/ml being observed. UV treatment of raw chicken fillet (0.192 J/cm(2)) reduced C. jejuni, E. coli, serovar Enteritidis, total viable counts, and Enterobacteriaceae by 0.76, 0.98, 1.34, 1.76, and 1.29 log CFU/g, respectively. Following UV treatment of packaging and surface materials, reductions of up to 3.97, 4.50, and 4.20 log CFU/cm(2) were obtained for C. jejuni, E. coli, and serovar Enteritidis, respectively (P < 0.05). Overall, the color of UV-treated chicken was not significantly affected (P ≥ 0.05). The findings of this study indicate that Campylobacter is susceptible to UV technology and that differences in sensitivities exist between investigated isolates. Overall, UV could be used for improving the microbiological quality of raw chicken and for decontaminating associated packaging and surface materials.

Effect of low temperatures (-18 to +5°C) on the texture of beef lean

The textural properties of beef over the temperature range -18 to +5°C were measured using Warner Bratzler (WB) and tensile techniques. In addition, the effects of rapid radio frequency (RF) tempering and slower conventional air tempering on texture were compared. Temperature showed a significant effect (P<0.05) on WB and tensile shear force, with higher values obtained at temperatures on or below -5°C. Work to fracture values showed two peaks at -15 and -3°C. Sample thickness and muscle fibre direction were also important factors affecting shear force, with samples cut across fibres showing higher values. Tempering method showed no effect (P⩾0.05) on the textural properties measured. In light of the rapid nature of RF tempering, these findings will be of interest to the meat industry.

Is laparoscopically assisted radical vaginal hysterectomy for cervical carcinoma safe? A case control study with follow up

OBJECTIVE

To compare a new surgical approach, laparoscopically assisted radical vaginal hysterectomy (LARVH) with open radical hysterectomy in women with cervical cancer. Can selected women benefit from the minimally invasive approach without compromising safety (recurrence rate) and morbidity (complications)?

DESIGN

Retrospective case control study.

SETTING

A tertiary referral unit for gynaecological malignancies.

POPULATION

Thirty women undergoing LARVH were included and compared with 30 women undergoing open radical surgery. The control group was matched for age, body mass index and disease stage.

METHODS

Retrospective collection of data from patient files and follow up.

MAIN OUTCOME MEASURES

Recurrence rate, complication rate, hospital stay, nodal counts, blood loss, operating time.

RESULTS

Recurrence rates were equal (6.7%). There was one death, in the LARVH group. Follow up was mean 31 months in the LARVH group and 30.9 months in the open group. Blood loss as measured by mean drop in haemoglobin was greater in the open group (2.03 versus 3.01 g/dl, P = 0.02). Transfusions were given in 40% of women in the open group and 16.7% in the LARVH group. Hospital stay was significantly less in the LARVH group (5.9 versus 7.8 nights, P = 0.003). Mean operating time was longer in the LARVH group (131 versus 187 minutes P = 0.0001). Mean nodal counts did not differ significantly (17.4 in open vs 14.8 in LARVH, P > 0.05). There were seven perioperative complications in the open group and four in the LARVH group. There have been two recurrences in each group (6.67%) at mean follow up of 31 (LARVH) and 30.9 (open) months.

CONCLUSIONS

The first 30 LARVH procedures performed in this unit are comparable in terms of safety (recurrence rate and complication rate) and economic factors (shorter hospital stay mitigating longer operating time). Further development of this technique is warranted.

The effects of cardiopulmonary bypass on plasma concentrations and protein binding of methohexital and thiopental

The effects of cardiopulmonary bypass (CPB) on plasma concentrations and protein binding of methohexital and thiopental were studied during continuous infusions in two groups of ten cardiac surgical patients. Patients were administered an infusion regimen designed to produce a stable total plasma concentration at 5 mg/L for methohexital and 10 mg/L for thiopental. Prior to the commencement of CPB the mean (+/-SD) total plasma methohexital concentration was 5.00 +/- 0.69 mg/L. This fell to 3.12 +/- 0.89 mg/L at two minutes after commencement of CPB, and rose to 4.67 +/- 1.11 mg/L by 75 minutes after commencement of CPB. The unbound fraction rose from 27.1 +/- 5.1% to 42.8 +/- 9.2% at five minutes after the start of CPB, and gradually decreased to 32.1 +/- 4.9% by 75 minutes. The unbound concentration (1.37 +/- 0.32 mg/L) was unaffected by the onset of CPB, being 1.51 +/- 0.49 mg/L at 75 minutes after the start of CPB. Thiopental followed a similar pattern to methohexital, with the total plasma thiopental concentration falling from 9.22 +/- 0.73 mg/L to 4.90 +/- 0.83 mg/L at two minutes after commencement of CPB, and rising again to 7.13 +/- 1.03 mg/L 75 minutes later. During the same period the unbound fraction of thiopental rose from 16.1 +/- 2.5% to 30.3 +/- 7.3% five minutes after the start of CPB, and fell gradually to 22.8 +/- 5.8% after 75 minutes. The unbound concentration (1.51 +/- 0.21 mg/L) was again unchanged by the onset of CPB, being 1.71 +/- 0.29 mg/L at 75 minutes. Plasma protein binding of both drugs correlated strongly with plasma albumin concentration, which decreased by 40% during CPB. It is concluded that hemodilution caused the reduction in total drug concentration and protein binding at the onset of CPB, but that the decrease in protein binding counteracted the dilution of unbound drug, resulting in a stable unbound concentration throughout CPB, and that this effect may be common for barbiturates.

Levels of serum chemokines discriminate clinical myelopathy associated with human T lymphotropic virus type 1 (HTLV-1)/tropical spastic paraparesis (HAM/TSP) disease from HTLV-1 carrier state

Approximately 5% of people infected with human T lymphotropic virus type 1 (HTLV-1) develop clinical myelopathy or tropical spastic paraparesis (HAM/TSP) that is associated with high-levels of Th1 cytokines, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha. Chemokines are known to induce cytokine secretion and direct the trafficking of immune cells to sites of disease. The present study measured serum chemokines correlated with autonomously released IFN-gamma in cell cultures. HTLV-1 infection was defined by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blot. Subjects included HTLV-1 carriers (n = 56), patients with HAM/TSP (n = 31) and healthy HTLV-1 seronegative volunteer controls (n = 20). Serum chemokines and IFN-gamma autonomously released by mononuclear cells in culture were quantified by ELISA. Compared to HTLV-1 carriers, serum chemokines in HAM/TSP patients showed significantly increased levels of CXCL9 and CXCL10, significantly diminished levels of CCL2 and similar amounts of CCL11 and CCL24. In contrast, CCL11 and CCL24 were significantly lower in serum of HAM/TSP patients than either control. IFN-gamma was positively correlated with CXCL9 and CXCL10 when HAM/TSP and HTLV-1 carriers were used as a combined group. However, despite a large proportion of HTLV-1 carriers having high IFN-gamma levels, these chemokines were not increased in carriers. This study showed that high levels of CXCL9 and CXCL10 in the systemic circulation and low serum CCL2 levels are features of HAM/TSP. HTLV-1 infection and Tax and/or additional viral encoded factor-mediated pathological processes triggering T cell activation with autogenous IFN-gamma release are probably involved in regulating chemokine release.

Relation between Gram-stain and clinical criteria for diagnosing bacterial vaginosis with special reference to Gram grade II evaluation

The aim of this study was to analyse how the results of Gram-staining vaginal smears correlated with the clinical criteria for determining the existence of bacterial vaginosis (BV) and, in particular, how the category defined as 'intermediate' or Gram grade II did so and its significance. Women attending an antenatal clinic with an abnormal vaginal flora, that is those who had Gram-stains of grades II or III, the latter considered to equate with BV, were given clindamycin or a placebo intravaginally and examined again on up to three occasions. Gram-stain readings of grade III correlated with the clinical criteria for BV on 356 (91.7%) of 388 occasions. Grade II readings covered the spectrum of clinical criteria and correlated with those for BV on 35 (37.2%) of 94 occasions. Grade I, recorded 231 times and seen usually after clindamycin treatment, was associated with BV only once. The sensitivity, specificity, positive predictive value and negative predictive value of the Gram stain for the diagnosis of BV, based on a combination of grades II and III, were 99.7%, 71.6%, 81% and 99.6%, respectively; based on grade III only, the values were 99.7%, 87.7%, 91.6% and 99.6%, respectively. Women reported a malodorous vaginal discharge on 49.2% of the occasions a grade III flora was seen and 13.3% of the times grade II was recorded. It was not associated with grade I and would seem a useful adjunct to the accepted clinical criteria for diagnosing BV. Each of the clinical criteria was found in about equal proportions (87%-91%) for women whose Gram grade was III. For grade II, an increased discharge was noted most often (76.5%) and 'clue' cells least often (24.5%). A positive amine test was the most specific, being associated with <1% of grade I smears. Of women with grade III status, 91% reverted to grade I after treatment with clindamycin for three days. In contrast, of women with grade II status, 53% reverted to grade I, as did 47% of those who were given a placebo. The 'intermediate' (grade II) category is a Gram-stain diagnosis and not one that can be made clinically. It is important to recognize as a distinct entity not only because amalgamation with grade III diminishes the specificity and positive predictive value of the Gram-stain for diagnosing BV, but also because women of grade II status usually fail to respond to clindamycin treatment, whereas those of grade III do not.

Seasonal flight activity of two Homalodisca species (Homoptera: Cicadellidae) that spread Xylella fastidiosa in southern California

Homalodisca coagulata (Say) and Homalodisca lacerta (Fowler) are vectors of a new bacterial disease of oleander in California known as oleander leaf scorch, induced by the bacterium Xylella fastidiosa. H. coagulata also has been implicated in the spread of the strain of X. fastidiosa that induces Pierce's disease of grapevines in California. We monitored the flight activity of H. coagulata and H. lacerta in oleander and citrus by using yellow sticky cards at three southern California locations where outbreaks of oleander leaf scorch have been documented, and where vector compliments are different. Areas sampled included a mesic coastal area (Irvine, CA) that supports predominantly H. coagulata and few H. lacerta, a dry inland location (Palm Desert, CA) that supports predominantly H. lacerta and few H. coagulata, and an intermediate area (Riverside, CA) supporting both Homalodisca species. From November 1996 to October 1999 peak catches of both Homalodisca species occurred during the midsummer at all locations. H. coagulata was trapped in greater numbers in citrus than in oleander at both the Riverside and the Irvine sites. Likewise, H. lacerta in Riverside was more associated with citrus than oleander, yet H. lacerta in Palm Desert was trapped in greater numbers in oleander than citrus.

A prospective randomised trial to compare the efficacy and safety of hemabate and syntometrine for the prevention of primary postpartum haemorrhage

In a prospective, open-label, assessor-blind, randomised parallel group study the efficacy and safety of Hemabate (Pharmacia-Upjohn Pharmaceuticals, Milton Keynes, Buckinghamshire) an analogue of 15-methyl-prostaglandin (PGF2alpha) analogue was compared with Syntometrine (Alliance Pharmaceuticals, Chippenham, Wilts) the standard combination of ergometrine and syntocinon used for the active management of the third stage of labour and the prevention of primary postpartum haemorrhage (PPH). The study was set in a district general hospital with approximately 4,000 deliveries annually. The study was discontinued at the time of the interim analysis because of unacceptable gastrointestinal side effects. At the time of the interim analysis, a total of 529 women had completed the study with 263 randomised to receive PGF2alpha and 266 to receive ergometrine and syntocinon. In a pre-specified subgroup analysis, women delivered vaginally were further subdivided into those considered to be at high or low risk of primary PPH. The measured blood loss and incidence of PPH was similar in both treatment groups whether delivered by caesarean section or vaginally independent of whether women were considered to be at high or low risk. Adverse gastrointestinal events were recorded more often in the Hemabate group. The most common symptom was diarrhoea which occurred in 21% of women who received Hemabate compared to only 0.8% of Syntometrine users. PGF2alpha is as effective as Syntometrine in the prophylaxis of primary PPH in all groups studied but there was a statistically significantly increased risk of diarrhoea among users of PGF2alpha.

Identification of Pneumocystis carinii in the lungs of infants dying of sudden infant death syndrome

BACKGROUND

Recently Pneumocystis carinii has been identified in a significant number of infants diagnosed as having died from sudden infant death syndrome (SIDS) in South America and Europe.

METHODS

We examined lung sections of 79 infants who died with a diagnosis of SIDS in Rochester, NY, and Connecticut for the presence of P. carinii.

RESULTS

Organisms with a characteristic silver stain appearance for P. carinii were identified in 14% of the lung sections.

CONCLUSIONS

These data suggest that a possible link between some cases of SIDS and infection with P. carinii should be further evaluated and that infection of young infants may serve as an important reservoir for human P. carinii.

Neurological and neuropathologic heterogeneity in two brothers with cobalamin C deficiency

Two adult brothers, one documented to have methylmalonic acidemia with homocystinuria, or cobalamin C deficiency, after autopsy, displayed severe but divergent neurological presentations. One exhibited a myelopathy and the other chronic endocrine problems (Schmidt's syndrome) followed by a neuropsychiatric and dementing disorder owing to cerebral perivascular demyelination. The recognition of cobalamin C deficiency has practical implications because it is one of the few inherited diseases of central white matter that is treatable.

Phase I and pharmacokinetic study of photodynamic therapy for high-grade gliomas using a novel boronated porphyrin

PURPOSE

To determine the recommended dose, toxicity profile, and pharmacokinetics of a novel boronated porphyrin (BOPP) for photodynamic therapy (PDT) of intracranial tumors.

PATIENTS AND METHODS

BOPP was administered alone in increasing doses (0.25, 0.5, 1.0, 2.0, 4.0, or 8.0 mg/kg) preoperatively in patients with intracranial tumors undergoing postresection PDT until dose-limiting toxicity (DLT) was observed.

RESULTS

Twenty-nine assessable patients with intracranial tumors received BOPP intravenously 24 hours before surgery. The recommended dose was 4 mg/kg. Dose escalation was limited by thrombocytopenia. The most common nonhematologic toxicity was skin photosensitivity. Pharmacokinetic parameters showed increased area under the plasma concentration-time curve and maximum concentration with increased dose. Tumor BOPP concentrations also increased with increased dose.

CONCLUSION

BOPP at a dose of 4 mg/kg was well tolerated. DLT was thrombocytopenia, and photosensitivity was the only other toxicity of note. The efficacy of PDT using BOPP requires further exploration.

Neonatal hepatic drug elimination

After the transition from in utero to newborn life, the neonate becomes solely reliant upon its own drug clearance processes to metabolise xenobiotics. Whilst most studies of neonatal hepatic drug elimination have focussed upon in vitro expression and activities of drug-metabolising enzymes, the rapid physiological changes in the early neonatal period of life also need to be considered. There are dramatic changes in neonatal liver blood flow and hepatic oxygenation due to the loss of the umbilical blood supply, the increasing portal vein blood flow, and the gradual closure of the ductus venosus shunt during the first week of life. These changes which may well affect the capacity of neonatal hepatic drug metabolism. The hepatic expression of cytochromes P450 1A2, 2C, 2D6, 2E1 and 3A4 develop at different rates in the postnatal period, whilst 3A7 expression diminishes. Hepatic glucuronidation in the human neonate is relatively immature at birth, which contrasts with the considerably more mature neonatal hepatic sulfation activity. Limited in vivo studies show that the human neonate can significantly metabolise xenobiotics but clearance is considerably less compared with the older infant and adult. The neonatal population included in pharmacological studies is highly heterogeneous with respect to age, body weight, ductus venosus closure and disease processes, making it difficult to interpret data arising from human neonatal studies. Studies in the perfused foetal and neonatal sheep liver have demonstrated how the oxidative and conjugative hepatic elimination of drugs by the intact organ is significantly increased during the first week of life, highlighting that future studies will need to consider the profound physiological changes that may influence neonatal hepatic drug elimination shortly after birth.

Right heart failure impairs hepatic elimination of p-nitrophenol without inducing changes in content or latency of hepatic UDP-glucuronosyltransferases

Congestive heart failure has been shown to affect oxidative drug metabolism, however, there has been little study of its effects on drug conjugation. Using the isolated perfused livers from rats with right ventricular failure (RVF) due to pulmonary artery constriction, we studied the effects of RVF on hepatic elimination of p-nitrophenol (PNP) under controlled flow and oxygen delivery conditions. Hepatic clearance of the drug was found to be significantly impaired in RVF as compared with the sham group (0.80 +/- 0.23 versus 1.28 +/- 0.26 ml/min/g of liver). The impairment of PNP clearance in RVF occurred in parallel with significant reduction in metabolic formation clearance of p-nitrophenyl-beta-D-glucuronide; the major metabolite of PNP (0.51 +/- 0.12 versus 1.03 +/- 0.26 ml/min/g of liver). The intrinsic drug-glucuronidation capacity of livers was evaluated by measuring the microsomal content and activity of the UDP-glucuronosyltransferase(s) (UDP-GT) toward p-nitrophenol. There was no significant difference between sham and the RVF groups in either the content or the activity of the UDP-GT. The latency of the UDP-GT enzymes in microsomes was measured and was found to be similar between the two groups. The results of this study show that RVF impairs hepatic elimination of PNP and that this appears to be independent of changes in hepatic perfusion and oxygenation or alterations in hepatic content, activity, and latency of the UDP-GT.

Self-tolerance and the composition of T cell repertoire

T cell recognition of self-major histocompatibility complex-peptide complexes dictates the composition of the T cell receptor repertoire. Research projects in our laboratory deal with the mechanisms that regulate the composition of the repertoire specific for self-antigens and the defects that can result in autoimmunity. Two different types of disease models are under investigation: juvenile (type I) diabetes and cancer. Both of these diseases are impacted by the presence of anti-self CD8 cells, yet in opposite ways. By understanding the mechanisms of peripheral tolerance and the reasons they fail in autoimmunity, we may learn how to prevent undesirable autoimmunity and how to encourage an autoimmune response when it is needed to eliminate tumor cells.

Impaired elimination of propranolol due to right heart failure: drug clearance in the isolated liver and its relationship to intrinsic metabolic capacity

It is unclear if reduced hepatic drug elimination in congestive heart failure is primarily due to impairment of enzyme function as a result of tissue hypoxia, to the direct effects of hepatic congestion, or to changes intrinsic to the liver, such as reductions in enzyme content and activity. We therefore compared propranolol clearance in perfused rat livers from animals with right ventricular failure (RVF) with that from control animals. Despite the fact that both groups were perfused at comparable flow rates, perfusion pressures, and levels of oxygen delivery, hepatic extraction of propranolol was significantly reduced in RVF livers (0.688 +/- 0.122 versus 0.991 +/- 0.006 ml/min/g of liver in controls, P <.001). This effect was reflected in a 97% reduction in propranolol intrinsic clearance in RVF livers (5 +/- 4 versus 172 +/- 82 ml/min/g of liver in controls, P <.01). In RVF livers, total hepatic CYP expression was reduced by 19% compared with controls, whereas cytochrome P450 isoenzymes 1A1/2 and 2D1 were reduced by 41 and 26%, respectively. Despite the 97% reduction in propranolol intrinsic clearance in perfused RVF liver, intrinsic clearance in microsomal preparations from the same livers was reduced by only 48% compared with controls (P <.05). These findings suggest that impaired propranolol clearance in RVF is not primarily accounted for by reduced hepatic oxygen delivery or by changes in hepatic content and activity of drug-metabolizing enzymes.

Prevalence of bacterial vaginosis in women attending one of three general practices for routine cervical cytology

A prospective observational study of asymptomatic women from three different general practices was set up to establish the incidence of bacterial vaginosis (BV). The study group comprised 287 women recalled to their general practitioner's surgery for routine cervical smears. The prevalence of an abnormal vaginal flora was about the same in women attending the 3 practices. Nearly 14% of women had abnormal vaginal flora and about 9% had BV on gram stain examination of vaginal secretions. This was 2-3 times more common than findings consistent with vaginal candidiasis (3.8%). Significant numbers of women with BV had received antifungal therapy suggesting a misdiagnosis. Because of its potential complications, women should be offered screening for BV in a well-women setting and, if found, should be treated if symptomatic or at risk of adverse obstetric or gynaecological sequelae.

The resolution of Californian populations of Liriomyza huidobrensis and Liriomyza trifolii (Diptera: Agromyzidae) using PCR

Liriomyza trifolii (Burgess) and Liriomyza huidobrensis (Blanchard) are important vegetable pests in California. Populations of each species differ in their impact in central and southern regions. This difference may be explained by geographical or host plant differences in each of the regions. We used random amplified polymorphic DNA polymerase chain reactions to assess genetic differences between two laboratory populations of each species collected from central and southern California. Individual L. trifolii from the two regions could be discriminated by the presence/absence of PCR products. No such qualitative differences were apparent in PCR products amplified from L. huidobrensis individuals, but the origins of individuals could be differentiated using a bootstrap analysis of marker frequencies. Marker primers were used to compare field and laboratory individuals. No evidence was found for the existence of further populations or of hybrid populations in central and southern California. The distribution of populations of L. huidobrensis was explained completely by geographical differences. As a consequence of the absence of leafminer infestations on the same host plant varieties in both regions, factors governing L. trifolii population distribution differences were less apparent. The presence of the same host plant varieties at both sites suggests that the two L. trifolii populations differ in host plant preference.

Neonatal hepatic propranolol elimination: studies in the isolated perfused neonatal sheep liver

Using the isolated perfused neonatal sheep liver model, we examined the disposition of propranolol (n = 8, age 0.25-10 days) and compared our findings with our previous study from the perfused near-term fetal sheep liver (Ring JA, et al. 1995. Drug Metab Dispos 23:190-196). Within 45 min of dosage, perfusate propranolol levels had fallen by three orders of magnitude to be less than the limit of detection. Perfusate disappearance curves were monoexponential in six experiments and biexponential in two experiments. The mean shunt-corrected hepatic extraction ratio was 0.92 +/- 0.09, much greater than that seen in the fetal sheep liver (0.26 +/- 0.13, P < 0.0001) but still less than values in the adult sheep (0.97). At the conclusion of the perfusion, 4-hydroxypropranolol was the major metabolite present and 5-hydroxypropranolol and N-desisopropylpropranolol were minor metabolites. We conclude that the isolated perfused neonatal sheep liver is a useful model with which to study the maturation of neonatal hepatic drug oxidation. Our study shows that propranolol is rapidly eliminated by the neonatal liver to form several metabolites at rates far greater than in the fetal liver, but rates of elimination have not yet reached that reported in the adult sheep liver.

Characterization of CD8+ T lymphocytes that persist after peripheral tolerance to a self antigen expressed in the pancreas

As a result of expression of the influenza hemagglutinin (HA) in the pancreatic islets, the repertoire of HA-specific CD8+ T lymphocytes in InsHA transgenic mice (D2 mice expressing the HA transgene under control of the rat insulin promoter) is comprised of cells that are less responsive to cognate Ag than are HA-specific CD8+ T lymphocytes from conventional mice. Previous studies of tolerance induction involving TCR transgenic T lymphocytes suggested that a variety of different mechanisms can reduce avidity for Ag, including altered cell surface expression of molecules involved in Ag recognition and a deficiency in signaling through the TCR complex. To determine which, if any, of these mechanisms pertain to CD8+ T lymphocytes within a conventional repertoire, HA-specific CD8+ T lymphocytes from B10.D2 mice and B10.D2 InsHA transgenic mice were compared with respect to expression of cell surface molecules, TCR gene utilization, binding of tetrameric KdHA complexes, lytic mechanisms, and diabetogenic potential. No evidence was found for reduced expression of TCR or CD8 by InsHA-derived CTL, nor was there evidence for a defect in triggering lytic activity. However, avidity differences between CD8+ clones correlated with their ability to bind KdHA tetramers. These results argue that most of the KdHA-specific T lymphocytes in InsHA mice are not intrinsically different from KdHA-specific T lymphocytes isolated from conventional animals. They simply express TCRs that are less avid in their binding to KdHA.

Effect of intravaginal clindamycin cream on pregnancy outcome and on abnormal vaginal microbial flora of pregnant women

OBJECTIVES

To determine whether intravaginal clindamycin cream reduces the incidence of abnormal pregnancy outcome in women with abnormal vaginal microbial flora graded as intermediate or BV and to investigate the effect of the antibiotic on vaginal microbial flora.

METHODS

A prospective cohort study of pregnant women in an antenatal clinic of a district general hospital. The subjects were 268 women who had abnormal vaginal microbial flora at first clinic visit by examination of a Gram-stained vaginal smear and 34 women with a normal vaginal flora. Two hundred and thirty-seven women were evaluable. Women with abnormal Gram-stained smears (graded as II or III) on clinic recall were randomised to receive treatment (intravaginal clindamycin cream) or placebo and followed to assess outcome of pregnancy, vaginal flora, and detection of Mycoplasma hominis and Ureaplasma urealyticum after treatment.

RESULTS

Abnormal outcomes of pregnancy were not significantly different in treated and placebo groups by Chi square (P = 0.2). However, women with grade III flora responded better to clindamycin than women with grade II flora by numbers of abnormal outcomes (P = 0.03) and return to normal vaginal flora (P = 0.01) (logistic regression analysis model). This may be due to differences in vaginal bacterial species in these grades. Women whose abnormal vaginal flora had spontaneously returned to normal on follow-up and were therefore not treated (revertants) had as many abnormal outcomes as placebos suggesting that damage by abnormal bacterial species occurred early in pregnancy.

CONCLUSIONS

Gram-stain screening distinguishing grade II from grade III flora may be helpful in prescribing treatment other than clindamycin for women with grade II flora. Earlier diagnosis and treatment may be more effective in preventing an abnormal outcome, possibly as soon as pregnancy is diagnosed or even offered as a pre-conception screen.