Effect of Physical Violence on Sexually Transmitted Infections and Treatment Seeking Behaviour among Female Sex Workers in Thane District,Maharashtra, India

Background

Violence against sex workers can heighten their vulnerability to HIV and other sexually transmitted infections (STIs). Evidence suggests the risk of acquiring STI/HIV infections among female sex workers (FSWs) who have experienced violence to be almost three-times higher than FSWs, who have not experienced violence. Moreover, an experience of physical and sexual violence makes it difficult for them to negotiate safer sex with their partners and often act as a barrier to utilization of prevention services.

Methods

This study utilizes data from 2785 FSWs aged 18 years and above who participated in a cross-sectional behavioural study conducted during 2013–14 in Thane district, Maharashtra. A probability-based two-stage cluster sampling method was used for data collection. This study assesses the effect of physical violence on self-reported STI symptoms (any STI and multiple STIs) and treatment seeking for the last STI symptom using propensity score matching method.

Results

About 18% of sampled FSWs reported physical violence at the time of the survey. The likelihood of experiencing such violence was significantly higher among FSWs who solicited clients at public places, engaged in other economic activities apart from sex work, had savings, and reported high client volume per week. FSWs experiencing violence were also inconsistent condom users while engaging in sex with regular partners and clients. The average adjusted effect of violence clearly depicted an increase in the risk of any STI (11%, p<0.05) and multiple STIs (8%, p<0.10) and reduction in treatment seeking (10%, p<0.05).

Conclusions

This study demonstrates a significant effect of physical violence on reporting of any STI symptom and treatment seeking. Findings call for the immediate inclusion of strategies aimed to address violence related challenges in HIV prevention program currently being provided at Thane district. Such strategies would further help in enhancing the access to tailored STI prevention and care services among FSWs in the district.     

Patch-clamp Capacitance Measurements and Ca2+ Imaging at Single Nerve Terminals in Retinal Slices

Visual stimuli are detected and conveyed over a wide dynamic range of light intensities and frequency changes by specialized neurons in the vertebrate retina. Two classes of retinal neurons, photoreceptors and bipolar cells, accomplish this by using ribbon-type active zones, which enable sustained and high-throughput neurotransmitter release over long time periods. ON-type mixed bipolar cell (Mb) terminals in the goldfish retina, which depolarize to light stimuli and receive mixed rod and cone photoreceptor input, are suitable for the study of ribbon-type synapses both due to their large size (~10-12 μm diameter) and to their numerous lateral and reciprocal synaptic connections with amacrine cell dendrites. Direct access to Mb bipolar cell terminals in goldfish retinal slices with the patch-clamp technique allows the measurement of presynaptic Ca²⁺ currents, membrane capacitance changes, and reciprocal synaptic feedback inhibition mediated by GABA_A and GABA_C receptors expressed on the terminals. Presynaptic membrane capacitance measurements of exocytosis allow one to study the short-term plasticity of excitatory neurotransmitter release ^14,15. In addition, short-term and long-term plasticity of inhibitory neurotransmitter release from amacrine cells can also be investigated by recordings of reciprocal feedback inhibition arriving at the Mb terminal ²¹. Over short periods of time (e.g. ~10 s), GABAergic reciprocal feedback inhibition from amacrine cells undergoes paired-pulse depression via GABA vesicle pool depletion ¹¹. The synaptic dynamics of retinal microcircuits in the inner plexiform layer of the retina can thus be directly studied.The brain-slice technique was introduced more than 40 years ago but is still very useful for the investigation of the electrical properties of neurons, both at the single cell soma, single dendrite or axon, and microcircuit synaptic level ¹⁹. Tissues that are too small to be glued directly onto the slicing chamber are often first embedded in agar (or placed onto a filter paper) and then sliced ^{20, 23, 18, 9}. In this video, we employ the pre-embedding agar technique using goldfish retina. Some of the giant bipolar cell terminals in our slices of goldfish retina are axotomized (axon-cut) during the slicing procedure. This allows us to isolate single presynaptic nerve terminal inputs, because recording from axotomized terminals excludes the signals from the soma-dendritic compartment. Alternatively, one can also record from intact Mb bipolar cells, by recording from terminals attached to axons that have not been cut during the slicing procedure. Overall, use of this experimental protocol will aid in studies of retinal synaptic physiology, microcircuit functional analysis, and synaptic transmission at ribbon synapses.     

Tumor metastasis in an orthotopic murine model of head and neck cancer: possible role of TGF-beta 1 secreted by the tumor cells

In an orthotopic murine model of head and neck cancer, combined subcutaneous and intratumoral vaccination with recombinant vaccinia virus expressing interleukin-2 (rvv-IL-2) induced significant tumor regression early on therapy. However, its efficacy was restricted by recurrent tumor growth and loco-regional metastases. In this study, we explored the mechanism of tumor metastasis. We compared the levels of expression of a number of molecules involved in tumor metastasis, which included transforming growth factor-beta1 (TGF-beta1), E-cadherin, matrix metalloproteinases (MMPs): MT1-MMP, MMP-2, MMP-9, their tissue inhibitors (TIMPs): TIMP-1/TIMP-2, and pro-angiogenic factors CD31, VEGF-R2, and iNOS between primary and metastatic tumors by real-time RT-PCR and immunohistochemistry. We detected spontaneous lymph node and tongue metastasis. Metastasis was delayed in rvv-IL-2 treated mice. Cultured tumor cells expressed negligible amount of TGF-beta1. Untreated or metastatic tumors, on the other hand, expressed high levels of TGF-beta1 and secreted TGF-beta1 in the sera of tumor-bearing mice. Levels of TGF-beta1 in the sera suddenly jumped at the time when tumor metastasis started. In the metastatic tumors, levels of MT1-MMP, MMP-2, and MMP-9 were significantly elevated (P < 0.001), while levels of TIMP-1/TIMP-2 and E-cadherin were decreased (P < 0.001) compared to control or primary tumors. Levels of CD31, VEGF-R2, and iNOS were also significantly elevated in the metastatic lesions (P < 0.001). The concurrence of high levels of TGF-beta1 in the sera, expression of proteins involved in metastasis and initiation of metastasis suggested possible role of TGF-beta1 in on setting the metastatic cascade in this model.     

Structural role of glycine in amyloid fibrils formed from transmembrane alpha-helices

Amyloid fibrils associated with diseases such as Alzheimer's are often derived from the transmembrane helices of membrane proteins. It is known that the fibrils have a cross-beta-sheet structure where main chain hydrogen bonding occurs between beta-strands in the direction of the fibril axis. However, the structural basis for how the membrane-spanning helix is converted into a beta-sheet or how protofibrils associate into fibrils is not known. Here, we use a model peptide corresponding to a portion of the single transmembrane helix of glycophorin A to investigate the structural role of glycine in amyloid-like fibrils formed from transmembrane helices. Glycophorin A contains a GxxxG motif that is found in many transmembrane sequences including that of the amyloid precursor protein and prion protein. We propose that glycine, which mediates helix interactions in membrane proteins, also provides key packing motifs when it occurs in beta-sheets. We show that glycines in the glycophorin A transmembrane helix promote extended beta-strand formation when the helix partitions into aqueous environments and stabilize the packing of beta-sheets in the formation of amyloid-like fibrils. We demonstrate that fibrillization can be disrupted with a new class of inhibitors that target the molecular grooves created by glycine.     

Long-Lived, High-Strength States of ICAM-1 Bonds to β2 Integrin, II: Lifetimes of LFA-1 Bonds Under Force in Leukocyte Signaling

Using single-molecule force spectroscopy to probe ICAM-1 interactions with recombinant α_Lβ₂ immobilized on microspheres and β₂ integrin on neutrophils, we quantified an impressive hierarchy of long-lived, high-strength states of the integrin bond, which start from basal levels with activation in solutions of divalent cations and shift dramatically upward to hyperactivated states with cell signaling. Taking advantage of very rare events, we used repeated measurements of bond lifetimes under steady ramps of force to achieve a direct assay for the off-rates of ICAM-1 from β₂ integrin throughout the course of each experiment. In our companion article I, we demonstrate the assay using results from tests of a monovalent ICAM-1 probe against recombinant α_Lβ₂ on microspheres in millimolar solutions of divalent cations (Ca²⁺, Mg²⁺, Mn²⁺). In this article, we examine the impact of inside-out and outside-in signaling in neutrophils on the lifetimes and mechanical strengths of ICAM-1 bonds to β₂ integrin on the cell surface. Even though ICAM-1 bonds to recombinant α_Lβ₂ on microspheres in Mg²⁺ or Mn²⁺ can live for long periods of time under slow pulling, here we show that stimulation of neutrophils in Mg²⁺ plus the chemokine IL-8 (i.e., inside-out signaling) induces several-hundred-fold longer lifetimes for ICAM-1 attachments to LFA-1, creating strong bonds at very slow pulling speeds where none are perceived in Mg²⁺ or Mn²⁺ alone. Similar changes are observed with outside-in signaling, i.e., long lifetimes and increased bond strength also occur when neutrophils are bound with the activating (anti-CD18) monoclonal 240Q. Limiting our investigation to rare events using very dilute ICAM-1 probes, we show that although the prolonged lifetimes of cell surface attachments for both inside-out and outside-in signaling exhibit single-bond-like statistics for dissociation under force, they are consistent with a tightly coupled dimeric ICAM-1 interaction with a pair of LFA-1 heterodimers.     

Relative burden of large CNVs on a range of neurodevelopmental phenotypes

While numerous studies have implicated copy number variants (CNVs) in a range of neurological phenotypes, the impact relative to disease severity has been difficult to ascertain due to small sample sizes, lack of phenotypic details, and heterogeneity in platforms used for discovery. Using a customized microarray enriched for genomic hotspots, we assayed for large CNVs among 1,227 individuals with various neurological deficits including dyslexia (376), sporadic autism (350), and intellectual disability (ID) (501), as well as 337 controls. We show that the frequency of large CNVs (>1 Mbp) is significantly greater for ID-associated phenotypes compared to autism (p = 9.58 × 10(-11), odds ratio = 4.59), dyslexia (p = 3.81 × 10(-18), odds ratio = 14.45), or controls (p = 2.75 × 10(-17), odds ratio = 13.71). There is a striking difference in the frequency of rare CNVs (>50 kbp) in autism (10%, p = 2.4 × 10(-6), odds ratio = 6) or ID (16%, p = 3.55 × 10(-12), odds ratio = 10) compared to dyslexia (2%) with essentially no difference in large CNV burden among dyslexia patients compared to controls. Rare CNVs were more likely to arise de novo (64%) in ID when compared to autism (40%) or dyslexia (0%). We observed a significantly increased large CNV burden in individuals with ID and multiple congenital anomalies (MCA) compared to ID alone (p = 0.001, odds ratio = 2.54). Our data suggest that large CNV burden positively correlates with the severity of childhood disability: ID with MCA being most severely affected and dyslexics being indistinguishable from controls. When autism without ID was considered separately, the increase in CNV burden was modest compared to controls (p = 0.07, odds ratio = 2.33).     

Net carbon exchange and evapotranspiration in postfire and intact sagebrush communities in the Great Basin

Invasion of non-native annuals across the Intermountain West is causing a widespread transition from perennial sagebrush communities to fire-prone annual herbaceous communities and grasslands. To determine how this invasion affects ecosystem function, carbon and water fluxes were quantified in three, paired sagebrush and adjacent postfire communities in the northern Great Basin using a 1-m³ gas exchange chamber. Most of the plant cover in the postfire communities was invasive species including Bromus tectorum L., Agropyron cristatum (L.) Gaertn and Sisymbrium altissimum L. Instantaneous morning net carbon exchange (NCE) and evapotranspiration (ET) in native shrub plots were greater than either intershrub or postfire plots. Native sagebrush communities were net carbon sinks (mean NCE 0.2–4.3 μmol m⁻² s⁻¹) throughout the growing season. The magnitude and seasonal variation of NCE in the postfire communities were controlled by the dominant species and availability of soil moisture. Net C exchange in postfire communities dominated by perennial bunchgrasses was similar to sagebrush. However, communities dominated by annuals (cheatgrass and mustard) had significantly lower NCE than sagebrush and became net sources of carbon to the atmosphere (NCE declined to −0.5 μmol m⁻² s⁻¹) with increased severity of the summer drought. Differences in the patterns of ET led to lower surface soil moisture content and increased soil temperatures during summer in the cheatgrass-dominated community compared to the adjacent sagebrush community. Intensive measurements at one site revealed that temporal and spatial patterns of NCE and ET were correlated most closely with changes in leaf area in each community. By altering the patterns of carbon and water exchange, conversion of native sagebrush to postfire invasive communities may disrupt surface-atmosphere exchange and degrade the carbon storage capacity of these systems.     

Widespread RNA segregation in a spiralian embryo

Asymmetric cell divisions are a crucial mode of cell fate specification in multicellular organisms, but their relative contribution to early embryonic patterning varies among taxa. In the embryo of the mollusc Ilyanassa, most of the early cell divisions are overtly asymmetric. During Ilyanassa early cleavage, mRNAs for several conserved developmental patterning genes localize to interphase centrosomes, and then during division they move to a portion of the cortex that will be inherited by one daughter cell. Here we report an unbiased survey of RNA localization in the Ilyanassa embryo, and examine the overall patterns of centrosomal localization during early development. We find that 3-4% of RNAs are specifically localized to centrosomes during early development, and the remainder are either ubiquitously distributed throughout the cytoplasm or weakly enriched on centrosomes compared with levels in the cytoplasm. We observe centrosomal localization of RNAs in all cells from zygote through the fifth cleavage cycle, and asymmetric RNA segregation in all divisions after the four-cell stage. Remarkably, each specifically localized message is found on centrosomes in a unique subset of cells during early cleavages, and most are found in unique sets of cells at the 24-cell stage. Several specifically localized RNAs are homologous to developmental regulatory proteins in other embryos. These results demonstrate that the mechanisms of localization and segregation are extraordinarily intricate in this system, and suggest that these events are involved in cell fate specification across all lineages in the early Ilyanassa embryo. We propose that greater reliance on segregation of determinants in early cleavage increases constraint on cleavage patterns in molluscs and other spiralian groups.     

Leaf temperature of soybean grown under elevated CO2 increases Aphis glycines (Hemiptera: Aphididae) population growth

Abstract Plants grown under elevated carbon dioxide (CO₂) experience physiological changes that influence their suitability as food for insects. To determine the effects of living on soybean (Glycine max Linnaeus) grown under elevated CO₂, population growth of the soybean aphid (Aphis glycines Matsumura) was determined at the SoyFACE research site at the University of Illinois, Urbana‐Champaign, Illinois, USA, grown under elevated (550 μL/L) and ambient (370 μL/L) levels of CO₂. Growth of aphid populations under elevated CO₂ was significantly greater after 1 week, with populations attaining twice the size of those on plants grown under ambient levels of CO₂. Soybean leaves grown under elevated levels of CO₂ were previously demonstrated at SoyFACE to have increased leaf temperature caused by reduced stomatal conductance. To separate the increased leaf temperature from other effects of elevated CO₂, air temperature was lowered while the CO₂ level was increased, which lowered overall leaf temperatures to those measured for leaves grown under ambient levels of CO₂. Aphid population growth on plants grown under elevated CO₂ and reduced air temperature was not significantly greater than on plants grown under ambient levels of CO₂. By increasing Glycine max leaf temperature, elevated CO₂ may increase populations of Aphis glycines and their impact on crop productivity.     

Heparin binds 8 kDa gelsolin cross-β-sheet oligomers and accelerates amyloidogenesis by hastening fibril extension

Glycosaminoglycans (GAGs) are highly sulfated linear polysaccharides prevalent in the extracellular matrix, and they associate with virtually all amyloid deposits in vivo. GAGs accelerate the aggregation of many amyloidogenic peptides in vitro, but little mechanistic evidence is available to explain why. Herein, spectroscopic methods demonstrate that GAGs do not affect the secondary structure of the monomeric 8 kDa amyloidogenic fragment of human plasma gelsolin. Moreover, monomerized 8 kDa gelsolin does not bind to heparin under physiological conditions. In contrast, 8 kDa gelsolin cross-β-sheet oligomers and amyloid fibrils bind strongly to heparin, apparently because of electrostatic interactions between the negatively charged polysaccharide and a positively charged region of the 8 kDa gelsolin assemblies. Our observations are consistent with a scaffolding mechanism whereby cross-β-sheet oligomers, upon formation, bind to GAGs, accelerating the fibril extension phase of amyloidogenesis, possibly by concentrating and orienting the oligomers to more efficiently form amyloid fibrils. Notably, heparin decreases the 8 kDa gelsolin concentration necessary for amyloid fibril formation, likely a consequence of fibril stabilization through heparin binding. Because GAG overexpression, which is common in amyloidosis, may represent a strategy for minimizing cross-β-sheet oligomer toxicity by transforming them into amyloid fibrils, the mechanism described herein for GAG-mediated acceleration of 8 kDa gelsolin amyloidogenesis provides a starting point for therapeutic strategy development. The addition of GAG mimetics, small molecule sulfonates shown to reduce the amyloid load in animal models of amyloidosis, to a heparin-accelerated 8 kDa gelsolin aggregation reaction mixture neither significantly alters the rate of amyloidogenesis nor prevents oligomers from binding to GAGs, calling into question their commonly accepted mechanism.