Trends and Factors Affecting Knowledge of and Stigma and Violence Towards Female Sex Workers in Morocco.

BACKGROUND: We investigate factors affecting HIV knowledge, stigma, and violence among female sex workers (FSW) in Agadir, Rabat, Fes, and Tangier, Morocco, over three rounds of HIV surveillance surveys (2012, 2016, and 2019) conducted using respondent-driven sampling (RDS). Multivariable analyses from RDS studies examining the relationships between variables are under-utilized, particularly analyses that combine multiple locations and years of data together in a principled manner. METHOD: We fit three weighted logistic regression models for HIV transmission knowledge, having been denied service (experienced stigma), and having been hit (experienced violence) in the last 12 months, and perform model selection using 41 possible explanatory variables. RESULTS: Variables significantly associated with higher risk included reasons for sex work, how FSW solicit clients, if female family members are also involved in sex work, ever being forced to have sex, and ever being arrested or jailed. There were also significant differences between cities and in trends over time, with HIV transmission knowledge increasing and having been denied health services and having been hit decreasing. CONCLUSION: We found associations indicating that some particularly vulnerable FSW may be subject to multiple intersecting risks related to HIV knowledge, stigma, and violence which may decrease their agency to receive proper HIV testing, care, and treatment. Although Morocco has made excellent progress in providing HIV services to vulnerable populations, this additional analysis will be useful as Morocco makes programmatic decisions related to ending HIV by 2030.

Recurrent seizures and brain pathology after inhibition of glutamine synthetase in the hippocampus in rats.

An excess of extracellular glutamate in the hippocampus has been linked to the generation of recurrent seizures and brain pathology in patients with medically intractable mesial temporal lobe epilepsy (MTLE). However, the mechanism which results in glutamate excess in MTLE remains unknown. We recently reported that the glutamate-metabolizing enzyme glutamine synthetase is deficient in the hippocampus in patients with MTLE, and we postulated that this deficiency is critically involved in the pathophysiology of the disease. To further explore the role of glutamine synthetase in MTLE we created a novel animal model of hippocampal glutamine synthetase deficiency by continuous (approximately 28 days) microinfusion of methionine sulfoximine (MSO: 0.625 to 2.5 microg/h) unilaterally into the hippocampus in rats. This treatment led to a deficiency in hippocampal glutamine synthetase activity by 82-97% versus saline. The majority (>95%) of the MSO-treated animals exhibited recurrent seizures that continued for several weeks. Some of the MSO-treated animals exhibited neuropathological features that were similar to mesial temporal sclerosis, such as hippocampal atrophy and patterned loss of hippocampal neurons. However, many MSO-treated animals displayed only minimal injury to the hippocampus, with no clear evidence of mesial temporal sclerosis. These findings support the hypothesis that a deficiency in hippocampal glutamine synthetase causes recurrent seizures, even in the absence of classical mesial temporal sclerosis, and that restoration of glutamine synthetase may represent a novel approach to therapeutic intervention in this disease.

Effects of continuous hypoxia on energy metabolism in cultured cerebro-cortical neurons.

Mechanisms underlying hypoxia-induced neuronal adaptation have not been fully elucidated. In the present study we investigated glucose metabolism and the activities of glycolytic and TCA cycle enzymes in cerebro-cortical neurons exposed to hypoxia (3 days in 1% of O2) or normoxia (room air). Hypoxia led to increased activities of LDH (194%), PK (90%), and HK (24%) and decreased activities of CS (15%) and GDH (34%). Neurons were incubated with [1-(13)C]glucose for 45 and 120 min under normoxic or hypoxic (120 min only) conditions and 13C enrichment determined in the medium and cell extract using 1H-{13C}-NMR. In hypoxia-treated neurons [3-(13)C]lactate release into the medium was 428% greater than in normoxia-treated controls (45-min normoxic incubation) and total flux through lactate was increased by 425%. In contrast glucose oxidation was reduced significantly in hypoxia-treated neurons, even when expressed relative to total cellular protein, which correlated with the reduced activities of the measured mitochondrial enzymes. The results suggest that surviving neurons adapt to prolonged hypoxia by up-regulation of glycolysis and down-regulation of oxidative energy metabolism, similar to certain other cell types. The factors leading to adaptation and survival for some neurons but not others remain to be determined.

A rapid gene delivery-based mouse model for early-stage Alzheimer disease-type tauopathy.

The perforant pathway projection from the entorhinal cortex (EC) to the hippocampal dentate gyrus is critically important for long-term memory and develops tau and amyloid pathologies and progressive degeneration starting in the early stages of Alzheimer disease (AD). However, perforant pathway function has not been assessed in experimental models of AD, and a therapeutic agent that protects its structure and function has not yet been identified. Therefore, we developed a new adeno-associated virus-based mouse model for perforant pathway tauopathy. Microinjection into the lateral EC of vectors designed to express either human tau bearing a pathogenic P301L mutation or enhanced green fluorescent protein as a control selectively drove transgene expression in lateral EC layer II perikarya and along the entire rostrocaudal extent of the lateral perforant pathway afferents and dentate terminal field. After human tau expression, hyperphosphorylated tau accumulated only within EC layer II perikarya, thereby modeling Braak stage I of transentorhinal AD tauopathy. Expression of pathologic human tau but not enhanced green fluorescent protein led to specific dose-dependent apoptotic death of perforant pathway neurons and loss of synapses in as little as 2 weeks. This novel adeno-associated virus-based method elicits rapid tauopathy and tau-mediated neurodegeneration localized to the mouse perforant pathway and represents a new experimental approach for studying tau-driven pathogenic processes and tau-based treatment strategies in a highly vulnerable neural circuit.

Combination therapy prevents amyloid-dependent and -independent structural changes.

Neuropathological features of Alzheimer's disease (AD) are recapitulated in transgenic mice expressing familial AD-causing mutations, but ectopic transgene overexpression makes it difficult to relate these abnormalities to disease pathogenesis. Alternatively, the APP/PS-1 double knock-in (DKI) mouse produces mutant amyloid precursor protein (APP) and presenilin-1 (PS-1) with normal levels and regulatory controls. Here, we investigated effects of amyloid on brain structure and neuroplasticity by vaccinating DKI mice with amyloid-ß starting at 8 months of age. At 14 months, vaccination blocked cerebral amyloid deposition and its attendant microglial activation. Neuropil abnormalities were pronounced only within plaques, and included circumscribed loss and dysmorphology of axons, dendrites, terminals and spines. Blockade of amyloid deposition restored neuropil integrity. Amyloid removal did not rescue reductions in the hippocampal neural progenitor and neuroblast populations, but adding 1 month of voluntary exercise to amyloid-ß vaccination markedly stimulated hippocampal neurogenesis. These results identify amyloid-dependent and -independent structural changes in the DKI mouse model of AD. Combining exercise with amyloid-directed immunotherapy produces greater restoration of brain structure and neuroplasticity than is achieved with either maneuver alone.

Amyloid deposition and advanced age fails to induce Alzheimer's type progression in a double knock-in mouse model.

It has been challenging to develop transgenic and gene-targeted mouse models that recapitulate all of the neuropathological features of Alzheimer's disease (AD). For example, in the APP/PS-1 double knock-in mutant mouse (DKI), frank neurodegeneration is not observed at middle age and synapse loss is pronounced only within amyloid plaques. Here, we investigated whether continued amyloid deposition and advanced age of 24-27 months lead to loss of neurons and synapses, tau hyperphosphorylation, and other pathological features of AD. We focused on the perforant pathway projection from entorhinal cortex to hippocampal dentate gyrus, since it is preferentially impacted by plaques, tangles, and neuronal loss early in the course of AD. Compared with wild type controls matched for age and gender, expression of neither reelin nor NeuN was altered in the entorhinal layer 2 neurons of origin. Retrograde labeling of the perforant pathway with Fluorogold indicated no cell loss, axonal atrophy, or nerve terminal degeneration. The lack of neuronal loss or atrophy was confirmed by volumetric analysis of the ventral dentate gyrus and immunostaining for a synaptic marker. We also searched for other hallmarks of AD neuropathology by labeling for hyperphosphorylated pre-tangle tau, accumulation of cathepsin D-containing autolysosomes, and cyclin A-positive neurons aberrantly re-entering the cell cycle. None of these AD pathologies were observed in the entorhinal cortex, dentate gyrus, or any other forebrain region. Our results indicate that the DKI mouse does not show appreciable Alzheimer-type disease progression, even at advanced age and in the phase of over 18 months of robust cerebral amyloid deposition. The insufficiency of amyloid deposition to induce other AD-type neuropathologies and neurodegeneration in the aging mouse brain suggests an important role for tauopathy or other factors for triggering the pathogenesis of AD.

A rat model of epilepsy in women: a tool to study physiological interactions between endocrine systems and seizures.

Epilepsy in women is influenced by endocrine status and antiepileptic drugs, but without an animal model, the effects of endocrine variables and antiepileptic drugs cannot be easily dissociated from the influence of epilepsy itself. Animal models have had limited utility because experimentally induced seizures typically result in reproductive failure. This study was conducted to develop an improved animal model. The muscarinic convulsant pilocarpine was used to elicit status epilepticus (SE) in adult female Sprague Dawley rats. The selective estrogen receptor modulator raloxifene was administered 30 min before pilocarpine. An anticonvulsant barbiturate, pentobarbital, was injected 5-10 min after the onset of SE and at least once thereafter to minimize acute convulsions. Mortality, morbidity, estrous cyclicity, and the ultimate success of the procedure (i.e. induction of recurrent, spontaneous seizures) were monitored. The combination of raloxifene and pentobarbital led to significantly improved estrous cyclicity compared with previous methods. Animals treated with raloxifene and pentobarbital became epileptic, as defined by the recurrence of spontaneous convulsions in the weeks after SE. The results of this study provide an improved animal model to examine the interactions between seizures and ovarian hormone secretion. The results also suggest that treatment of SE with raloxifene may benefit women with SE.

Changes in hippocampal function of ovariectomized rats after sequential low doses of estradiol to simulate the preovulatory estrogen surge.

In adult female rats, robust hippocampal changes occur when estradiol rises on the morning of proestrus. Whether estradiol mediates these changes, however, remains unknown. To address this issue, we used sequential injections of estradiol to simulate two key components of the preovulatory surge: the rapid rise in estradiol on proestrous morning, and the slower rise during the preceding day, diestrus 2. Animals were examined mid-morning of simulated proestrus, and compared to vehicle-treated or intact rats. In both simulated and intact rats, CA1-evoked responses were potentiated in hippocampal slices, and presynaptic mechanisms appeared to contribute. In CA3, multiple population spikes were evoked in response to mossy fiber stimuli, and expression of brain-derived neurotrophic factor was increased. Simulation of proestrous morning also improved performance on object and place recognition tests, in comparison to vehicle treatment. Surprisingly, effects on CA1-evoked responses showed a dependence on estradiol during simulated diestrus 2, as well as a dependence on proestrous morning. Increasing estradiol above the physiological range on proestrous morning paradoxically decreased evoked responses in CA1. However, CA3 pyramidal cell activity increased further, and became synchronized. Together, the results confirm that physiological estradiol levels are sufficient to profoundly affect hippocampal function. In addition: (i) changes on proestrous morning appear to depend on slow increases in estradiol during the preceding day; (ii) effects are extremely sensitive to the peak serum level on proestrous morning; and (iii) there are striking subfield differences within the hippocampus.

Manganese-induced neurotoxicity is differentially enhanced by glutathione depletion in astrocytoma and neuroblastoma cells.

Manganese (Mn) is neurotoxic: the underlying mechanisms have not been fully elucidated. L: -Buthionine-(S,R)-sulfoximine (BSO) is an irreversible inhibitor of gamma-glutamylcysteine synthetase, an important enzyme in glutathione (GSH) synthesis. To test the hypothesis that BSO modulates Mn toxicity, we investigated the effects of treatment of U-87 or SK-N-SH cells with MnCl(2), BSO, or MnCl(2) plus BSO. We monitored cell viability using MTT assay, staining with HO-33342 to assess live and/or apoptotic cells, and staining with propidium iodide (PI) to assess necrotic cells; we also measured cellular glutathione. Our results indicate decreased viability in both cell types when treated with MnCl(2) or BSO: Mn was more toxic to SK-N-SH cells, whereas BSO was more toxic to U-87 cells. Because BSO treatment accentuated Mn toxicity in both cell lines, GSH may act to combat Mn toxicity. Thus, further investigation in oxidative stress mediated by glutathione depletion will unravel new Mn toxicity mechanism(s).

Differential glutamate dehydrogenase (GDH) activity profile in patients with temporal lobe epilepsy.

PURPOSE: Pathophysiologic mechanisms underlying temporal lobe epilepsy (TLE) are still poorly understood. One major hypothesis links alterations in energy metabolism to glutamate excitotoxicity associated with seizures in TLE. The purpose of this study was to determine whether changes in the activities of enzymes critical in energy and neurotransmitter metabolism contributed to the alterations in metabolic status leading to the excitotoxic effects of glutamate. METHODS: Activities of four key enzymes involved in energy metabolism and glutamate cycling in the brain [aspartate aminotransferase (AAT), citrate synthase (CS), glutamate dehydrogenase (GDH), and lactate dehydrogenase (LDH)] were measured in anterolateral temporal neocortical and hippocampal tissues obtained from three different groups of medically intractable epilepsy patients having either mesial, paradoxical, or mass lesion-associated temporal lobe epilepsy (MTLE, PTLE, MaTLE), respectively. RESULTS: We found that GDH activity was significantly decreased in the temporal cortex mainly in the MTLE group. A similar trend was recognized in the hippocampus of the MTLE. In all three patient groups, GDH activity was considerably lower, and AAT and LDH activities were higher in cortex of MTLE as compared with the corresponding activities in hippocampus (p<0.05). In the MTLE cortex and hippocampus, GDH activities were negatively correlated with the duration since the first intractable seizure. CONCLUSIONS: Our results support the hypothesis suggesting major alteration in GDH activity mainly in the MTLE group. It is proposed that significant alterations in the enzyme activities may be contributing to decreased metabolism of glutamate, leading to its accumulation.