Fetal Pathology in Spontaneous Abortion

Pregnancy is a truly remarkable process. While a single fertilised cell is developing into a complete individual, the mother usually tolerates this rapidly growing "transplant", her enlarging uterus and the accompanying dramatic hormonal changes with equanimity. Perhaps it is hardly surprising that such a complex process sometimes fails.Changing times have influenced the degree of importance society attaches to fetal and perinatal loss. It is not very long since recurrent pregnancy, high infant mortality and stillbirth were accepted with resignation, as normal hazards of living. However with effective contraception, careful obstetric supervision and the improvements in nutrition, hygiene and health which have come to affluent western societies, the present expectation is of a chosen number of pregnancies, precisely timed and with perfect outcome. Yet about one in ten couples is infertile; nearly one in five recognised pregnancies ends in spontaneous abortion (1) and an even greater number of unrecognised early pregnancies are aborted (2). Fetal loss is still a common problem

Update on CJD

In March 1996 the discovery of a new form of Creutzfeldt-Jakob disease (CJD) was announced to a shocked world. In order to understand why this news took the headlines by storm, it is necessary to trace the history of this rare disease and in particular its links with bovine spongiform encephalopathy (BSE), or “mad cow disease”. By 1996, Britain had been in the throes of the BSE epidemic for ten years and it was believed that cows had contracted the disease by consumption of scrapie contaminated food-stuff, scrapie being a similar but much older disease in sheep. Because this represented a species jump from sheep to cows, it was predicted in many quarters that BSE posed a new threat to human health. Therefore the Government took steps to remove BSE contaminated products from the human food chain and the Department of Health set up a surveillance programme to monitor the incidence of CJD in UK

Brain cell reservoirs of latent virus in presymptomatic HIV-infected individuals

We detected HIV-1 DNA in pure populations of perivascular macrophages, parenchymal microglia, and astrocytes, isolated using laser microdissection from brain tissue of five untreated individuals who died in the presymptomatic stage of infection from non-HIV causes. HIV-1 DNA was detected in the three cell populations, most consistently in perivascular macrophages, without evidence of productive infection. The percentage of PCR reactions detecting HIV-1 DNA in perivascular macrophages correlated inversely with peripheral blood CD4 counts. These findings demonstrate that brain cell reservoirs of latent HIV-1 exist before pathological HIV encephalitis and suggest that perivascular macrophage trafficking of latent virus into the brain increases with immunosuppression

Parenteral Transmission of the Novel Human Parvovirus PARV4

Transmission routes of PARV4, a newly discovered human parvovirus, were investigated by determining frequencies of persistent infections using autopsy samples from different risk groups. Predominantly parenteral routes of transmission were demonstrated by infection restricted to injection drug users and persons with hemophilia and absence of infection in homosexual men with AIDS and low-risk controls

Frequent Infection of Cerebellar Granule Cell Neurons by Polyomavirus JC in Progressive Multifocal Leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) occurs most often in immunosuppressed individuals. The lesions of PML result from astrocyte and oligodendrocyte infection by the polyomavirus JC (JCV); JCV has also been shown to infect and destroy cerebellar granule cell neurons (GCNs) in 2 HIV-positive patients. To determine the prevalence and pattern of JCV infection in GCNs we immunostained formalin-fixed, paraffin-embedded cerebellar samples from 40 HIV-positive and 3 HIV-negative PML patients for JCV, glial and neuronal markers. JCV infection was detected in 30 patients (70%); 28 (93%) of these had JCV-infected cells in the granule cell layer (GCL); JCV-infected GCNs were demonstrated in 15/19 (79%) tested cases. JCV regulatory T antigen (T Ag) was expressed more frequently and abundantly in GCNs than JCV VP1 capsid protein. None of 37 HIV-negative controls but 1/35 (3%) HIV-positive subjects without PML had distinct foci of JCV-infected GCNs. Thus, JCV infection of GCNs is frequent in PML patients and may occur in the absence of cerebellar white matter demyelinating lesions. The predominance of T Ag over VP1 expression in GCNs suggests that they may be the site of early or latent central nervous system JCV infection. These results indicate that infection of GCNs is an important, previously overlooked aspect of JCV pathogenesis in immunosuppressed individuals

Macrophage entry mediated by HIV Envs from brain and lymphoid tissues is determined by the capacity to use low CD4 levels and overall efficiency of fusion

AbstractHIV infects macrophages and microglia in the central nervous system (CNS), which express lower levels of CD4 than CD4+ T cells in peripheral blood. To investigate mechanisms of HIV neurotropism, full-length env genes were cloned from autopsy brain and lymphoid tissues from 4 AIDS patients with HIV-associated dementia (HAD). Characterization of 55 functional Env clones demonstrated that Envs with reduced dependence on CD4 for fusion and viral entry are more frequent in brain compared to lymphoid tissue. Envs that mediated efficient entry into macrophages were frequent in brain but were also present in lymphoid tissue. For most Envs, entry into macrophages correlated with overall fusion activity at all levels of CD4 and CCR5. gp160 nucleotide sequences were compartmentalized in brain versus lymphoid tissue within each patient. Proline at position 308 in the V3 loop of gp120 was associated with brain compartmentalization in 3 patients, but mutagenesis studies suggested that P308 alone does not contribute to reduced CD4 dependence or macrophage-tropism. These results suggest that HIV adaptation to replicate in the CNS selects for Envs with reduced CD4 dependence and increased fusion activity. Macrophage-tropic Envs are frequent in brain but are also present in lymphoid tissues of AIDS patients with HAD, and entry into macrophages in the CNS and other tissues is dependent on the ability to use low receptor levels and overall efficiency of fusion

Using Evolutionary Conserved Modules in Gene Networks as a Strategy to Leverage High Throughput Gene Expression Queries

Background: Large-scale gene expression studies have not yielded the expected insight into genetic networks that control complex processes. These anticipated discoveries have been limited not by technology, but by a lack of effective strategies to investigate the data in a manageable and meaningful way. Previous work suggests that using a pre-determined seednetwork of gene relationships to query large-scale expression datasets is an effective way to generate candidate genes for further study and network expansion or enrichment. Based on the evolutionary conservation of gene relationships, we test the hypothesis that a seed network derived from studies of retinal cell determination in the fly, Drosophila melanogaster, will be an effective way to identify novel candidate genes for their role in mouse retinal development. Methodology/Principal Findings: Our results demonstrate that a number of gene relationships regulating retinal cell differentiation in the fly are identifiable as pairwise correlations between genes from developing mouse retina. In addition, we demonstrate that our extracted seed-network of correlated mouse genes is an effective tool for querying datasets and provides a context to generate hypotheses. Our query identified 46 genes correlated with our extracted seed-network members. Approximately 54% of these candidates had been previously linked to the developing brain and 33% had been previously linked to the developing retina. Five of six candidate genes investigated further were validated by experiments examining spatial and temporal protein expression in the developing retina. Conclusions/Significance: We present an effective strategy for pursuing a systems biology approach that utilizes an evolutionary comparative framework between two model organisms, fly and mouse. Future implementation of this strategy will be useful to determine the extent of network conservation, not just gene conservation, between species and will facilitate the use of prior biological knowledge to develop rational systems-based hypotheses

Quantifying primaquine effectiveness and improving adherence: a round table discussion of the APMEN Vivax Working Group.

The goal to eliminate malaria from the Asia-Pacific by 2030 will require the safe and widespread delivery of effective radical cure of malaria. In October 2017, the Asia Pacific Malaria Elimination Network Vivax Working Group met to discuss the impediments to primaquine (PQ) radical cure, how these can be overcome and the methodological difficulties in assessing clinical effectiveness of radical cure. The salient discussions of this meeting which involved 110 representatives from 18 partner countries and 21 institutional partner organizations are reported. Context specific strategies to improve adherence are needed to increase understanding and awareness of PQ within affected communities; these must include education and health promotion programs. Lessons learned from other disease programs highlight that a package of approaches has the greatest potential to change patient and prescriber habits, however optimizing the components of this approach and quantifying their effectiveness is challenging. In a trial setting, the reactivity of participants results in patients altering their behaviour and creates inherent bias. Although bias can be reduced by integrating data collection into the routine health care and surveillance systems, this comes at a cost of decreasing the detection of clinical outcomes. Measuring adherence and the factors that relate to it, also requires an in-depth understanding of the context and the underlying sociocultural logic that supports it. Reaching the elimination goal will require innovative approaches to improve radical cure for vivax malaria, as well as the methods to evaluate its effectiveness

Biochemical­­– and biophysical–induced barriergenesis in the blood brain barrier: a review of barriergenic factors for use in in vitro models

Central nervous system (CNS) pathologies are a prevalent problem in aging populations, creating a need to understand the underlying events in these diseases and develop efficient CNS‐targeting drugs. The importance of the blood‐brain barrier (BBB) has become evident, acting both as a physical barrier to drug entry into the CNS, and potentially as the cause or aggravator of CNS diseases. The development of a biomimetic BBB in vitro model is required for the understanding of BBB‐related pathologies and in the screening of drugs targeting the CNS. There is currently a great interest in understanding the influence of biochemical and biophysical factors, as these have the potential to greatly improve the barrier function of brain microvascular endothelial cells (BMECs). Recent advances in understanding how these may regulate barriergenesis in BMECs can help promote the development of improved BBB in vitro models, and therefore novel interventional therapies for pathologies related to its disruption. This review provides an overview of specific biochemical and biomechanical cues in the formation of the BBB, with a focus on in vitro models and how these might recapitulate BBB function