Cognitive impairment in people living with HIV: consensus recommendations for a new approach

Current approaches to classifying cognitive impairment in people living with HIV can overestimate disease burden and lead to ambiguity around disease mechanisms. The 2007 criteria for HIV-associated neurocognitive disorders (HAND), sometimes called the Frascati criteria, can falsely classify over 20% of cognitively healthy individuals as having cognitive impairment. Minimum criteria for HAND are met on the basis of performance on cognitive tests alone, which might not be appropriate for populations with diverse educational and socioeconomic backgrounds. Imprecise phenotyping of cognitive impairment can limit mechanistic research, biomarker discovery and treatment trials. Importantly, overestimation of cognitive impairment carries the risk of creating fear among people living with HIV and worsening stigma and discrimination towards these individuals. To address this issue, we established the International HIV-Cognition Working Group, which is globally representative and involves the community of people living with HIV. We reached consensus on six recommendations towards a new approach for diagnosis and classification of cognitive impairment in people living with HIV, intended to focus discussion and debate going forward. We propose the conceptual separation of HIV-associated brain injury - including active or pretreatment legacy damage - from other causes of brain injury occurring in people living with HIV. We suggest moving away from a quantitative neuropsychological approach towards an emphasis on clinical context. Our recommendations are intended to better represent the changing profile of cognitive impairment in people living with HIV in diverse global settings and to provide a clearer framework of classification for clinical management and research studies.

Associations of the COVID-19 pandemic with quality of life: A cross-sectional study of older-age people with and without HIV in rural Uganda

Background

COVID-19-related lockdowns and other public health measures may have differentially affected the quality of life (QOL) of older people with and without human immunodeficiency virus (HIV) in rural Uganda.

Methods

The Quality of Life and Aging with HIV in Rural Uganda study enrolled people with and without HIV aged over 49 from October 2020 to October 2021. We collected data on COVID-19-related stressors (behavior changes, concerns, interruptions in health care, income, and food) and the participants' QOL. We used linear regression to estimate the associations between COVID-19-related stressors and QOL, adjusting for demographic characteristics, mental and physical health, and time before vs after the lockdown during the second COVID-19 wave in Uganda. Interaction between HIV and COVID-19-related stressors evaluated effect modification.

Results

We analyzed complete data from 562 participants. Mean age was 58 (standard deviation (SD) = 7); 265 (47%) participants were female, 386 (69%) were married, 279 (50%) had HIV, and 400 (71%) were farmers. Those making ≥5 COVID-19-related behavior changes compared to those making ≤2 had worse general QOL (estimated linear regression coefficient (b) = - 4.77; 95% confidence interval (CI) = -6.61, -2.94) and health-related QOL (b = -4.60; 95% CI = -8.69, -0.51). Having access to sufficient food after the start of the COVID-19 pandemic (b = 3.10, 95% CI = 1.54, 4.66) and being interviewed after the start of the second lockdown (b = 2.79, 95% CI = 1.30, 4.28) were associated with better general QOL. Having HIV was associated with better health-related QOL (b = 5.67, 95% CI = 2.91,8.42). HIV was not associated with, nor did it modify the association of COVID-19-related stressors with general QOL.

Conclusions

In the context of the COVID-19 pandemic in an HIV-endemic, low-resource setting, there was reduced QOL among older Ugandans making multiple COVID-19 related behavioral changes. Nonetheless, good QOL during the second COVID-19 wave may suggest resilience among older Ugandans.

Priorities for health and wellbeing for older people with and without HIV in Uganda: a qualitative methods study

Introduction

With improved HIV treatment availability in sub‐Saharan Africa, the population of older people with HIV (PWH) is growing. In this qualitative study, we intended to understand (1) the lived experiences of ageing people in rural Uganda, with and without HIV, (2) their fears and health priorities as they grow older.

Methods

We conducted 36 semi‐structured interviews with individuals with and without HIV in Mbarara, Uganda from October 2019 to February 2020. Interview guide topics included priorities in older age, physical functioning in daily activities, social functioning, HIV‐related stigma and the impact of multimorbidity on health and independence. Interviews were conducted in Runyankole, transcribed, translated and inductively coded thematically by two researchers with tests for inter‐coder reliability.

Results

The respondents were purposively sampled to be evenly divided by sex and HIV serostatus. The median age of respondents was 57 (49–73). Two‐thirds were married or cohabitating, 94% had biological children and 75% cited farming as their primary livelihood. Overall, PWH considered themselves as healthy or healthier than people without HIV (PWOH). PWH rarely considered their HIV status a barrier to a healthy life, but some reported a constant sense of anxiety as it relates to their long‐term health. Irrespective of HIV status, nearly all respondents noted concerns about memory loss, physical pain, reductions in energy and the effect of these changes on their ability to complete physical tasks like small‐scale farming, and activities of daily living important to the quality of life, such as participating in community groups. Increasing reliance on others for social, physical and financial support was also a common theme. The most prevalent health concern among participants involved the threat of non‐communicable diseases and perceptions that physical functioning may diminish.

Conclusions

In rural Uganda, we found that PWH consider themselves to be healthy and do not anticipate a different ageing experience from PWOH. Common priorities shared by both groups included the desire for physical and financial independence, health maintenance and social support for daily functioning and social needs. Entities supporting geriatric care in Uganda would benefit from attention to concerns about functional limitations and reported needs as people age with and without HIV.

Neuroimmunology of CNS HIV Infection: A Narrative Review

This short review provides an overview of the interactions of human immunodeficiency virus type 1 (HIV), immune and inflammatory reactions, and CNS injury over the course of infection. Systemic infection is the overall driver of disease and serves as the “platform” for eventual CNS injury, setting the level of immune dysfunction and providing both the HIV seeding and immune-inflammatory responses to the CNS. These systemic processes determine the timing of and vulnerability to HIV-related neuronal injury which occurs in a separate “compartment” with features that parallel their systemic counterparts but also evolve independently. Direct CNS HIV infection, along with opportunistic infections, can have profound neurological consequences for the infected individual. HIV-related CNS morbidities are of worldwide importance but are enhanced by the particular epidemiological, socioeconomic and environmental factors that heighten the impact of HIV infection in Africa.

The ASA score predicts infections, cardiovascular complications, and hospital readmissions after hip fracture - A nationwide cohort study

This study examines the association between the ASA physical status classification score at hip fracture surgery and severe postoperative complications in patients aged 60 and older. Among both men and women, ASA scores consistently predict a wide range of complications including infections, cardiovascular complications, hospital readmissions, and death.

INTRODUCTION

Hip fractures are common in aging populations and associated with poor prognosis. This study examines how the American Society of Anaesthesiologists (ASA) physical status classification is related to severe complications among hip fracture patients including infections, cardiovascular diseases, hospital readmissions, and death.

METHODS

Based on a linkage of the Swedish National Inpatient Register with the Swedish National Registry for Hip Fractures (RIKSHÖFT), this study includes patients aged 60+ with first hip fracture between 1998 and 2017. We estimated associations between ASA score and complications during the hospital stay and during 1 year after hip fracture using multivariable-adjusted logistic regression and Cox proportional hazard regression.

RESULTS

The study population included 170,193 hip fracture patients of which 24% died and 39% were readmitted to hospital within 1 year. The most common complications were urinary tract infections, pneumonia, second hip fractures, and heart failure. Among both men and women, higher ASA scores were consistently associated with higher risks for all complications included in this study. The strongest associations were observed for heart failure, myocardial infarction, pneumonia, and death.

CONCLUSION

ASA scores are routinely assessed in clinical practice and predict a wide range of postoperative complications among hip fracture patients. Since many complications may be preventable through adequate drug treatment, rehabilitation, and risk awareness, future studies should examine the mechanisms linking ASA scores to complication risk in order to improve preventive strategies. Particularly, the high risk of cardiovascular complications among patients with high ASA scores deserves clinical and scientific attention.

HIV-associated neurocognitive impairment in stable people living with HIV on ART in rural Tanzania

OBJECTIVES

Few studies have assessed cognitive impairment among healthy people living with HIV (PLWH) who are stable on antiretroviral treatment (ART) in sub-Saharan Africa.

METHODS

We conducted a cross-sectional study among a random sample of stable adult PLWH from rural Tanzania on ART for more than 1 year and without immunological failure or pre-existing neurological disease. We evaluated the prevalence and risk factors for neurocognitive impairment (NCI), assessed through neuropsychological tests, functional and depression questionnaires and defined as a mean Z-score ≤ -1 in two or more cognitive domains.

RESULTS

Among 243 participants [median age = 44.3 years (interquartile range: 36-52] and 71% female] we found a rate of NCI of 19.3% (95% confidence interval: 14.8-24.8%). Memory and psychomotor domains demonstrated the highest impairment. Independent predictors of NCI were age and self-reported alcohol use. Other classical risk factors were not associated with HIV-associated NCI.

CONCLUSION

Despite effective ART roll-out, NCI remained a prevalent condition in this healthy rural Tanzanian population of PLWH on ART. Age and alcohol use were key risk factors.

A Systematic Review of Non-Traumatic Spinal Cord Injuries in Sub-Saharan Africa and a Proposed Diagnostic Algorithm for Resource-Limited Settings

Background

Non-traumatic myelopathy is common in Africa and there are geographic differences in etiology. Clinical management is challenging due to the broad differential diagnosis and the lack of diagnostics. The objective of this systematic review is to determine the most common etiologies of non-traumatic myelopathy in sub-Saharan Africa to inform a regionally appropriate diagnostic algorithm.

Methods

We conducted a systemic review searching Medline and Embase databases using the following search terms: “Non traumatic spinal cord injury” or “myelopathy” with limitations to epidemiology or etiologies and Sub-Saharan Africa. We described the frequencies of the different etiologies and proposed a diagnostic algorithm based on the most common diagnoses.

Results

We identified 19 studies all performed at tertiary institutions; 15 were retrospective and 13 were published in the era of the HIV epidemic. Compressive bone lesions accounted for more than 48% of the cases; a majority were Pott’s disease and metastatic disease. No diagnosis was identified in up to 30% of cases in most studies; in particular, definitive diagnoses of non-compressive lesions were rare and a majority were clinical diagnoses of transverse myelitis and HIV myelopathy. Age and HIV were major determinants of etiology.

Conclusion

Compressive myelopathies represent a majority of non-traumatic myelopathies in sub-Saharan Africa, and most were due to Pott’s disease. Non-compressive myelopathies have not been well defined and need further research in Africa. We recommend a standardized approach to management of non-traumatic myelopathy focused on identifying treatable conditions with tests widely available in low-resource settings.

Neurology and the Global HIV Epidemic

The vast majority of people living with human immunodeficiency virus (HIV) infection reside in resource-limited settings. As compared with resource-rich settings, there are important differences in the epidemiology and outcomes of HIV infection in resource-limited settings. Nonetheless, little HIV neurology research occurs in these regions. We will first review clinical, epidemiological, and translational HIV neurology research originating from resource-limited settings. We will then discuss the barriers to conducting neurologic research, such as limited human resources, diagnostics, and access to medications. Finally, we will review existing initiatives to build capacity for research in resource-limited settings. Despite the barriers, there is growing interest in and opportunities for collaborative international neurologic research. Including diverse viral and human populations from across the globe in research opens possibilities for important implementation science, clinically oriented science, and basic science discoveries.

Creation of the AAN Global Health Section, Part I: introduction and background

The idea of a Global Health Section within the American Academy of Neurology (AAN) came from a group of neurologists with active work in sub-Saharan Africa, who believed that the AAN could provide a greater leadership role in supporting the advancement of quality neurologic training, research, and patient care in low and middle-income countries (LMICs). Initially a Special Interest Group, the Global Health Section was approved for full section status in September 2011 and endorsed by the AAN Board of Directors in October 2011. The Global Health Section currently consists of over 200 members. In a 2-part series, we present a summary of the Global Health Section strategic plan and vision for future activities.

Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010

BACKGROUND

Non-fatal health outcomes from diseases and injuries are a crucial consideration in the promotion and monitoring of individual and population health. The Global Burden of Disease (GBD) studies done in 1990 and 2000 have been the only studies to quantify non-fatal health outcomes across an exhaustive set of disorders at the global and regional level. Neither effort quantified uncertainty in prevalence or years lived with disability (YLDs).

METHODS

Of the 291 diseases and injuries in the GBD cause list, 289 cause disability. For 1160 sequelae of the 289 diseases and injuries, we undertook a systematic analysis of prevalence, incidence, remission, duration, and excess mortality. Sources included published studies, case notification, population-based cancer registries, other disease registries, antenatal clinic serosurveillance, hospital discharge data, ambulatory care data, household surveys, other surveys, and cohort studies. For most sequelae, we used a Bayesian meta-regression method, DisMod-MR, designed to address key limitations in descriptive epidemiological data, including missing data, inconsistency, and large methodological variation between data sources. For some disorders, we used natural history models, geospatial models, back-calculation models (models calculating incidence from population mortality rates and case fatality), or registration completeness models (models adjusting for incomplete registration with health-system access and other covariates). Disability weights for 220 unique health states were used to capture the severity of health loss. YLDs by cause at age, sex, country, and year levels were adjusted for comorbidity with simulation methods. We included uncertainty estimates at all stages of the analysis.

FINDINGS

Global prevalence for all ages combined in 2010 across the 1160 sequelae ranged from fewer than one case per 1 million people to 350,000 cases per 1 million people. Prevalence and severity of health loss were weakly correlated (correlation coefficient -0·37). In 2010, there were 777 million YLDs from all causes, up from 583 million in 1990. The main contributors to global YLDs were mental and behavioural disorders, musculoskeletal disorders, and diabetes or endocrine diseases. The leading specific causes of YLDs were much the same in 2010 as they were in 1990: low back pain, major depressive disorder, iron-deficiency anaemia, neck pain, chronic obstructive pulmonary disease, anxiety disorders, migraine, diabetes, and falls. Age-specific prevalence of YLDs increased with age in all regions and has decreased slightly from 1990 to 2010. Regional patterns of the leading causes of YLDs were more similar compared with years of life lost due to premature mortality. Neglected tropical diseases, HIV/AIDS, tuberculosis, malaria, and anaemia were important causes of YLDs in sub-Saharan Africa.

INTERPRETATION

Rates of YLDs per 100,000 people have remained largely constant over time but rise steadily with age. Population growth and ageing have increased YLD numbers and crude rates over the past two decades. Prevalences of the most common causes of YLDs, such as mental and behavioural disorders and musculoskeletal disorders, have not decreased. Health systems will need to address the needs of the rising numbers of individuals with a range of disorders that largely cause disability but not mortality. Quantification of the burden of non-fatal health outcomes will be crucial to understand how well health systems are responding to these challenges. Effective and affordable strategies to deal with this rising burden are an urgent priority for health systems in most parts of the world.

FUNDING

Bill & Melinda Gates Foundation.

Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010

BACKGROUND

Measuring disease and injury burden in populations requires a composite metric that captures both premature mortality and the prevalence and severity of ill-health. The 1990 Global Burden of Disease study proposed disability-adjusted life years (DALYs) to measure disease burden. No comprehensive update of disease burden worldwide incorporating a systematic reassessment of disease and injury-specific epidemiology has been done since the 1990 study. We aimed to calculate disease burden worldwide and for 21 regions for 1990, 2005, and 2010 with methods to enable meaningful comparisons over time.

METHODS

We calculated DALYs as the sum of years of life lost (YLLs) and years lived with disability (YLDs). DALYs were calculated for 291 causes, 20 age groups, both sexes, and for 187 countries, and aggregated to regional and global estimates of disease burden for three points in time with strictly comparable definitions and methods. YLLs were calculated from age-sex-country-time-specific estimates of mortality by cause, with death by standardised lost life expectancy at each age. YLDs were calculated as prevalence of 1160 disabling sequelae, by age, sex, and cause, and weighted by new disability weights for each health state. Neither YLLs nor YLDs were age-weighted or discounted. Uncertainty around cause-specific DALYs was calculated incorporating uncertainty in levels of all-cause mortality, cause-specific mortality, prevalence, and disability weights.

FINDINGS

Global DALYs remained stable from 1990 (2·503 billion) to 2010 (2·490 billion). Crude DALYs per 1000 decreased by 23% (472 per 1000 to 361 per 1000). An important shift has occurred in DALY composition with the contribution of deaths and disability among children (younger than 5 years of age) declining from 41% of global DALYs in 1990 to 25% in 2010. YLLs typically account for about half of disease burden in more developed regions (high-income Asia Pacific, western Europe, high-income North America, and Australasia), rising to over 80% of DALYs in sub-Saharan Africa. In 1990, 47% of DALYs worldwide were from communicable, maternal, neonatal, and nutritional disorders, 43% from non-communicable diseases, and 10% from injuries. By 2010, this had shifted to 35%, 54%, and 11%, respectively. Ischaemic heart disease was the leading cause of DALYs worldwide in 2010 (up from fourth rank in 1990, increasing by 29%), followed by lower respiratory infections (top rank in 1990; 44% decline in DALYs), stroke (fifth in 1990; 19% increase), diarrhoeal diseases (second in 1990; 51% decrease), and HIV/AIDS (33rd in 1990; 351% increase). Major depressive disorder increased from 15th to 11th rank (37% increase) and road injury from 12th to 10th rank (34% increase). Substantial heterogeneity exists in rankings of leading causes of disease burden among regions.

INTERPRETATION

Global disease burden has continued to shift away from communicable to non-communicable diseases and from premature death to years lived with disability. In sub-Saharan Africa, however, many communicable, maternal, neonatal, and nutritional disorders remain the dominant causes of disease burden. The rising burden from mental and behavioural disorders, musculoskeletal disorders, and diabetes will impose new challenges on health systems. Regional heterogeneity highlights the importance of understanding local burden of disease and setting goals and targets for the post-2015 agenda taking such patterns into account. Because of improved definitions, methods, and data, these results for 1990 and 2010 supersede all previously published Global Burden of Disease results.

FUNDING

Bill & Melinda Gates Foundation.

Common values in assessing health outcomes from disease and injury: disability weights measurement study for the Global Burden of Disease Study 2010

BACKGROUND

Measurement of the global burden of disease with disability-adjusted life-years (DALYs) requires disability weights that quantify health losses for all non-fatal consequences of disease and injury. There has been extensive debate about a range of conceptual and methodological issues concerning the definition and measurement of these weights. Our primary objective was a comprehensive re-estimation of disability weights for the Global Burden of Disease Study 2010 through a large-scale empirical investigation in which judgments about health losses associated with many causes of disease and injury were elicited from the general public in diverse communities through a new, standardised approach.

METHODS

We surveyed respondents in two ways: household surveys of adults aged 18 years or older (face-to-face interviews in Bangladesh, Indonesia, Peru, and Tanzania; telephone interviews in the USA) between Oct 28, 2009, and June 23, 2010; and an open-access web-based survey between July 26, 2010, and May 16, 2011. The surveys used paired comparison questions, in which respondents considered two hypothetical individuals with different, randomly selected health states and indicated which person they regarded as healthier. The web survey added questions about population health equivalence, which compared the overall health benefits of different life-saving or disease-prevention programmes. We analysed paired comparison responses with probit regression analysis on all 220 unique states in the study. We used results from the population health equivalence responses to anchor the results from the paired comparisons on the disability weight scale from 0 (implying no loss of health) to 1 (implying a health loss equivalent to death). Additionally, we compared new disability weights with those used in WHO's most recent update of the Global Burden of Disease Study for 2004.

FINDINGS

13,902 individuals participated in household surveys and 16,328 in the web survey. Analysis of paired comparison responses indicated a high degree of consistency across surveys: correlations between individual survey results and results from analysis of the pooled dataset were 0·9 or higher in all surveys except in Bangladesh (r=0·75). Most of the 220 disability weights were located on the mild end of the severity scale, with 58 (26%) having weights below 0·05. Five (11%) states had weights below 0·01, such as mild anaemia, mild hearing or vision loss, and secondary infertility. The health states with the highest disability weights were acute schizophrenia (0·76) and severe multiple sclerosis (0·71). We identified a broad pattern of agreement between the old and new weights (r=0·70), particularly in the moderate-to-severe range. However, in the mild range below 0·2, many states had significantly lower weights in our study than previously.

INTERPRETATION

This study represents the most extensive empirical effort as yet to measure disability weights. By contrast with the popular hypothesis that disability assessments vary widely across samples with different cultural environments, we have reported strong evidence of highly consistent results.

FUNDING

Bill & Melinda Gates Foundation.

[Super-resolution optical microscopy of the organ of Corti. Investigations on the fine structure of the inner hair cell afferent synapse by the 4Pi and STED techniques]

BACKGROUND

Inner hair cells encode sound into action potentials in the auditory nerve. Spiral ganglion neurons form the afferent innervation of inner hair cells via the hair cell synapse. The structure and function of this ribbon-type synapse is considered to have a major impact on the sound encoding process itself. In this study we have used conventional confocal microscopy as well as super-resolution techniques to investigate the synaptic organization in the inner hair cells of mice.

MATERIAL AND METHODS

Functionally relevant proteins of the afferent inner hair cell synapse were selectively marked using immunohistochemical methods and investigated with conventional confocal and super-resolution 4Pi- and stimulated emission depletion (STED) techniques.

RESULTS

Synapse and innervation density was mapped over the entire tonotopic axis. We found inner hair cells in the region of best hearing to have about twice the number of afferent fibres compared to the apex or base of the cochlea. For the first time 4Pi and STED microscopic techniques were employed to resolve the fine structure of these synapses beyond the resolution of conventional light microscopy. With 4Pi a resolution of approximately 100 nm in the z-axis direction is feasible. In practice STED delivers an effective resolution between 150 and 30 nm, depending on the power of the lasers employed. Synapses at different tonotopic positions of the cochlea exhibit no relevant structural differences at this level of resolution. The 4Pi and STED microscopic techniques are capable of showing the structure of afferent synapses in the organ of Corti with unsurpassed resolution. These images contribute to our understanding of sound-encoding mechanisms in the inner ear.

Training needs and evaluation of a neuro-HIV training module for non-physician healthcare workers in western Kenya

BACKGROUND

Recent efforts to improve neurological care in resource-limited settings have focused on providing training to non-physician healthcare workers.

METHODS

A one-day neuro-HIV training module emphasizing HIV-associated dementia (HAD) and peripheral neuropathy was provided to 71 health care workers in western Kenya. Pre- and post-tests were administered to 55 participants.

RESULTS

Mean age of participants was 29 years, 53% were clinical officers and 40% were nurses. Self-reported comfort was significantly higher for treating medical versus neurologic conditions (p<0.001). After training, participants identified more neuropathy etiologies (pre=5.6/9 possible correct etiologies; post=8.0/9; p<0.001). Only 4% of participants at baseline and 6% (p=0.31) post-training could correctly identify HAD diagnostic criteria, though there were fewer mis-identified criteria such as abnormal level of consciousness (pre=82%; post=43%; p<0.001) and hallucinations (pre=57%; post=15%; p<0.001).

CONCLUSIONS

Healthcare workers were more comfortable treating medical than neurological conditions. This training significantly improved knowledge about etiologies of neuropathy and decreased some misconceptions about HAD.

Utility of quantitative sensory testing and screening tools in identifying HIV-associated peripheral neuropathy in Western Kenya: pilot testing

BACKGROUND/AIM

Neuropathy is the most common neurologic complication of HIV but is widely under-diagnosed in resource-constrained settings. We aimed to identify tools that accurately distinguish individuals with moderate/severe peripheral neuropathy and can be administered by non-physician healthcare workers (HCW) in resource-constrained settings.

METHODS

We enrolled a convenience sample of 30 HIV-infected outpatients from a Kenyan HIV-care clinic. A HCW administered the Neuropathy Severity Score (NSS), Single Question Neuropathy Screen (Single-QNS), Subjective Peripheral Neuropathy Screen (Subjective-PNS), and Brief Peripheral Neuropathy Screen (Brief-PNS). Monofilament, graduated tuning fork, and two-point discrimination examinations were performed. Tools were validated against a neurologist's clinical assessment of moderate/severe neuropathy.

RESULTS

The sample was 57% male, mean age 38.6 years, and mean CD4 count 324 cells/µL. Neurologist's assessment identified 20% (6/30) with moderate/severe neuropathy. Diagnostic utilities for moderate/severe neuropathy were: Single-QNS--83% sensitivity, 71% specificity; Subjective-PNS-total--83% sensitivity, 83% specificity; Subjective-PNS-max and NSS--67% sensitivity, 92% specificity; Brief-PNS--0% sensitivity, 92% specificity; monofilament--100% sensitivity, 88% specificity; graduated tuning fork--83% sensitivity, 88% specificity; two-point discrimination--75% sensitivity, 58% specificity.

CONCLUSIONS

Pilot testing suggests Single-QNS, Subjective-PNS, and monofilament examination accurately identify HIV-infected patients with moderate/severe neuropathy and may be useful diagnostic tools in resource-constrained settings.

Genetics of novelty seeking, amphetamine self-administration and reinstatement using inbred rats

Previous research using outbred rats indicates that individual differences in activity in a novel environment predict sensitivity to the reinforcing effect of psychostimulant drugs. The current study examined if the link between responses related to novelty and amphetamine self-administration is heritable. Twelve inbred rat strains were assessed for locomotor activity in a novel environment, preference for a novel environment, and intravenous amphetamine self-administration (acquisition, extinction and amphetamine-induced reinstatement). Strain differences were observed in activity in a novel environment, novelty preference and amphetamine self-administration, indicating a genetic influence for each of these behaviors. While there was no relation between activity in an inescapable novel environment and amphetamine self-administration, strain-dependent differences in novelty preference were positively correlated with the amount of amphetamine self-administered. There was also a positive correlation between the dose-dependent rate of amphetamine self-administration and magnitude of reinstatement. These results show that the activity in an inescapable novel environment and the preference for a novel environment are different genetically, and thus likely to reflect different behavioral constructs. Moreover, these results implicate a genetic influence on the relation between novelty seeking and stimulant self-administration, as well as on the relation between stimulant reward and reinstatement.

Global disparities in the epilepsy treatment gap: a systematic review

OBJECTIVE

To describe the magnitude and variation of the epilepsy treatment gap worldwide.

METHODS

We conducted a systematic review of the peer-reviewed literature published from 1 January 1987 to 1 September 2007 in all languages using PubMed and EMBASE. The purpose was to identify population-based studies of epilepsy prevalence that reported the epilepsy treatment gap, defined as the proportion of people with epilepsy who require but do not receive treatment. Negative binomial regression models were used to assess trends and associations.

FINDINGS

The treatment gap was over 75% in low-income countries and over 50% in most lower middle- and upper middle-income countries, while many high-income countries had gaps of less than 10%. However, treatment gaps varied widely both between and within countries. They were significantly higher in rural areas (rate ratio, RR: 2.01; 95% confidence interval, CI: 1.40-2.89) and countries with lower World Bank income classification (RR: 1.55; 95% CI: 1.32-1.82). There was no significant trend in treatment gap over time (RR: 0.92; 95% CI: 0.79-1.07).

CONCLUSION

There is dramatic global disparity in the care for epilepsy between high- and low- income countries, and between rural and urban settings. Our understanding of the factors affecting the treatment gap is limited; future investigations should explore other potential explanations of the gap.

Estimation of quantal size and number of functional active zones at the calyx of Held synapse by nonstationary EPSC variance analysis

At the large excitatory calyx of Held synapse, the quantal size during an evoked EPSC and the number of active zones contributing to transmission are not known. We developed a nonstationary variant of EPSC fluctuation analysis to determine these quantal parameters. AMPA receptor-mediated EPSCs were recorded in slices of young (postnatal 8-10 d) rats after afferent fiber stimulation, delivered in trains to induce synaptic depression. The means and the variances of EPSC amplitudes were calculated across trains for each stimulus number. During 10 Hz trains at 2 mm Ca(2+) concentration ([Ca(2+)]), we found linear EPSC variance-mean relationships, with a slope that was in good agreement with the quantal size obtained from amplitude distributions of spontaneous miniature EPSCs. At high release probability with 10 or 15 mm [Ca(2+)], competitive antagonists were used to partially block EPSCs. Under these conditions, the EPSC variance-mean plots could be fitted with parabolas, giving estimates of quantal size and of the binomial parameter N. With the rapidly dissociating antagonist kynurenic acid, quantal sizes were larger than with a slowly dissociating antagonist, suggesting that the effective glutamate concentration was increased at high release probability. Considering the possibility of multivesicular release and moderate saturation of postsynaptic AMPA receptors, we conclude that the binomial parameter N (637 +/- 117; mean +/- SEM) represents an upper limit estimate of the number of functional active zones. We estimate that during normal synaptic transmission, the probability of vesicle fusion at single active zones is in the range of 0.25-0.4.

Secondary amenorrhea and infertility caused by an inhibin-B-producing ovarian fibrothecoma

OBJECTIVE

To report a case of secondary amenorrhea and infertility caused by an inhibin-B-producing ovarian fibrothecoma.

DESIGN

Case report.

SETTING

Academic medical center.

PATIENT

A 37-year-old woman with a 2-year history of secondary amenorrhea and infertility.

INTERVENTION(S)

Operative removal of a 5-cm ovarian fibrothecoma.

MAIN OUTCOME MEASURE(S)

Luteinizing hormone, FSH, E2, inhibin-B, TSH, and prolactin measured preoperatively and postoperatively. Immunostaining of tumor cells for inhibin and LH.

RESULT(S)

Preoperative hormone levels were as follows: FSH, 1.7 mIU/mL; LH, 23.4 mIU/mL; E2, 31 pg/mL; and inhibin B, 1,154 pg/mL. Three weeks postoperatively, the FSH was 1.5 mIU/mL, LH decreased to 7.1 mIU/mL, E2 increased to 276 pg/mL, and inhibin-B decreased to 17 pg/mL. The fibrothecoma did not stain for LH but was strongly positive for inhibin. Regular menstrual cycles resumed 28 days postoperatively.

CONCLUSION(S)

Inhibin-B produced by an ovarian tumor profoundly suppressed FSH levels and resulted in secondary amenorrhea and infertility. Use of sensitive and specific immunoassays for inhibin-A and -B may aid in the differential diagnosis of hormonally active ovarian tumors.

Released fraction and total size of a pool of immediately available transmitter quanta at a calyx synapse

The size of a pool of readily releasable vesicles at a giant brainstem synapse, the calyx of Held, was probed with three independent approaches. Using simultaneous pre- and postsynaptic whole-cell recordings, two forms of presynaptic Ca2+ stimuli were applied in rapid succession: uncaging of Ca2+ by flash photolysis and the opening of voltage-gated Ca2+ channels. The ensuing transmitter release showed a nearly complete cross-inhibition between the two stimuli, indicating the depletion of a limited pool of about 700 transmitter quanta. The pool size was confirmed in experiments using enhanced extracellular Ca2+ concentrations, as well as short, high-frequency stimulus trains. The results reveal a surprisingly large pool of functionally available vesicles, of which a fraction of about 0.2 is released by a single presynaptic action potential under physiological conditions.

Analysis of clonal CD8+ T cell expansions in normal individuals and patients with rheumatoid arthritis

In the course of studying the circulating TCR repertoire in humans, we noted several individuals with an increase in the percentage of CD8+ T cells expressing a particular V region. In some cases, these CD8 expansions were dramatic, occupying over 40% of the total CD8 repertoire. Using a panel of mAbs to different TCR V regions, we found that over 30% of healthy adults (&gt; 35 years of age) harbor an expansion that alters the peripheral blood CD8 TCR repertoire. A wide range of V regions were expressed by these expansions. Considering that the mAbs used cover only a portion of the V beta repertoire, the data suggest that over 70% of adults are likely to harbor such expansions. Junctional region sequencing showed that the CD8 subset expansions were clonal, and serial studies as long as 4 years showed that they persisted indefinitely. Expansions were not identified in the CD4 population. Discordant expression of one large V beta 6.7+ clone was found in one identical twin set, suggesting the possibility that an environmental exposure is involved in their generation and/or expansion. In one large family, we found five family members with a large CD8 subset expansion. Remarkably similar usage of J beta regions was noted, and two individuals demonstrated V beta 3-expressing clones with homologous CDR3 regions, differing by only one major substitution. The repertoire data from this family suggest that the T cell clones have arisen in response to a common Ag. Studies of patients with rheumatoid arthritis found a significantly increased frequency of circulating CD8 subset expansions that expressed a different V region repertoire compared with the healthy individuals studied. Overall, our results emphasize a frequent alteration in the human CD8 TCR repertoire, most likely related to an environmental exposure, in both healthy individuals and patients with rheumatoid arthritis. The presence of these expansions will be important to consider in any study of human TCR repertoire, and their implication for health and disease will be important to understand.

Analysis of clonal CD8+ T cell expansions in normal individuals and patients with rheumatoid arthritis

In the course of studying the circulating TCR repertoire in humans, we noted several individuals with an increase in the percentage of CD8+ T cells expressing a particular V region. In some cases, these CD8 expansions were dramatic, occupying over 40% of the total CD8 repertoire. Using a panel of mAbs to different TCR V regions, we found that over 30% of healthy adults (> 35 years of age) harbor an expansion that alters the peripheral blood CD8 TCR repertoire. A wide range of V regions were expressed by these expansions. Considering that the mAbs used cover only a portion of the V beta repertoire, the data suggest that over 70% of adults are likely to harbor such expansions. Junctional region sequencing showed that the CD8 subset expansions were clonal, and serial studies as long as 4 years showed that they persisted indefinitely. Expansions were not identified in the CD4 population. Discordant expression of one large V beta 6.7+ clone was found in one identical twin set, suggesting the possibility that an environmental exposure is involved in their generation and/or expansion. In one large family, we found five family members with a large CD8 subset expansion. Remarkably similar usage of J beta regions was noted, and two individuals demonstrated V beta 3-expressing clones with homologous CDR3 regions, differing by only one major substitution. The repertoire data from this family suggest that the T cell clones have arisen in response to a common Ag. Studies of patients with rheumatoid arthritis found a significantly increased frequency of circulating CD8 subset expansions that expressed a different V region repertoire compared with the healthy individuals studied. Overall, our results emphasize a frequent alteration in the human CD8 TCR repertoire, most likely related to an environmental exposure, in both healthy individuals and patients with rheumatoid arthritis. The presence of these expansions will be important to consider in any study of human TCR repertoire, and their implication for health and disease will be important to understand.

Dihydropyridine calcium antagonists depress the amplitude of the plasma melatonin cycle in baboons

An investigation into the effects of verapamil and some dihydropyridine derivatives on plasma melatonin levels was undertaken in baboons. In a number of separate experiments, groups of young male chacma baboons (mean body weight 13 kg) received intraperitoneal injections of the drugs, under ketamine anaesthesia, roughly 30 minutes prior to the following time points: 1200, 1800, 0000, 0200, 0600 and 1200 h. Lights went off at 1800 h and came on at 0600 h. The drugs used, and their respective dosages (expressed per kg body mass), were verapamil up to 4 mg/kg, nifedipine at 0.2 mg/kg, nitrendipine at 0.5 mg/kg and nisoldipine at 0.1 mg/kg. Blood samples, taken at the said time points, were assayed for melatonin. The nighttime peak of the plasma melatonin cycle was significantly depressed by all three dihydropyridine calcium antagonists (up to 40%), while verapamil, even at the relatively high total dose of 24 mg/kg per day, had no significant effect on the circulating plasma melatonin levels.

Circadian changes in microtubules, synaptic ribbons and synaptic ribbon fields in the pinealocytes of the baboon (Papio ursinus)

In baboons kept under controlled lighting conditions, microtubules (MT) are readily seen in the perikaryal cytoplasm and in the perivascular processes of pinealocytes. A significant increase in the number of MT, single synaptic ribbons (SR) and the formation of synaptic ribbon fields (RF, i.e. organelles which consist of multiple dense rodlets or plates, and vesicles), occur during the dark phase of a circadian light-dark cycle. MT may act as "tracks" for the oriented flow of vesicles derived from the smooth endoplasmic reticulum, to cytoplasmic sites where RF are being formed. The origin of the dense rodlets of RF remains unknown. Structural differences between SR and RF indicate that the latter organelles are not directly involved in impulse propagation between adjacent baboon pinealocytes. RF may function as storage organelles for some of the pineal secretory products which are formed in large amounts during the dark phase.

Microfilaments, the smooth endoplasmic reticulum and synaptic ribbon fields in the pinealocytes of the baboon (Papio ursinus)

Microfilaments (MF, 5-8 nm in diameter) are a prominent feature of the pinealocyte cytoplasm of baboons (Papio ursinus) kept under controlled lighting conditions. MF occurred as a filamentous network in these cells during the light phase of the diurnal light-dark cycle, while a close structural association was noted between MF and the membranes of the smooth endoplasmic reticulum (SER). This association was especially evident during the dark period. Increased numbers of single synaptic ribbons (SR, vesicle-crowned rodlets), together with large aggregations of SR, i.e., ribbon fields (RF), were seen in the pinealocyte cytoplasm of baboons killed during the dark phase. It is suggested that the vesicles of RF may arise from those of the SER and that MF may play a role in the movement of SER-vesicles to those areas of the cytoplasm where new RF are being formed.

Carcinoma of the breast. A clinical study

An analysis of 1,686 surgically treated carcinomas of the breast in one community showed no statistically significant differences in five- and ten-year survival for simple, modified radical, or radical mastectomy. Further confirmation was obtained by computation of relative survival which in addition showed that older women more nearly approach normal life expectancy than younger ones. Bilaterality was found to be a decreasing function of age. Patients with medial and lateral tumors did not have significantly different rates of survival or sites of distant metastases.