Publications by authors named "Nader Halim"

Taking treatments from bench to bedside, or bench to community, requires a viable pathway connecting molecular science to global need through public and private research funding, clinical development, drug marketing, and policy making. In this paper, the authors present a systematic analysis of the effectiveness of translating basic science into reduced global burden of disease as a proxy for systemic public health impact. They pose a compound research question: Is the current drug development pipeline aligned with current and future global burden of disease, and, if not, where do the disconnections occur?

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Glucose metabolism in nervous tissue has been proposed to occur in a compartmentalized manner with astrocytes contributing largely to glycolysis and neurons being the primary site of glucose oxidation. However, mammalian astrocytes and neurons both contain mitochondria, and it remains unclear why in culture neurons oxidize glucose, lactate, and pyruvate to a much larger extent than astrocytes. The objective of this study was to determine whether pyruvate metabolism is differentially regulated in cultured neurons versus astrocytes.

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High lactate generation and low glucose oxidation, despite normal oxygen conditions, are commonly seen in cancer cells and tumors. Historically known as the Warburg effect, this altered metabolic phenotype has long been correlated with malignant progression and poor clinical outcome. However, the mechanistic relationship between altered glucose metabolism and malignancy remains poorly understood.

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A number of postmortem studies have found decreased pH in brains of patients with schizophrenia. Insofar as lower pH has been associated with decreased mRNA expression in postmortem human brain, decreased pH in schizophrenia may represent an important potential confound in comparisons between patients and controls. We hypothesized that decreased pH may be related to increased concentration of lactic acid.

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DISC1 has been identified as a schizophrenia susceptibility gene based on linkage and SNP association studies and clinical data suggesting that risk SNPs impact on hippocampal structure and function. In cell and animal models, C-terminus-truncated DISC1 disrupts intracellular transport, neural architecture and migration, perhaps because it fails to interact with binding partners involved in neuronal differentiation such as fasciculation and elongation protein zeta-1 (FEZ1), platelet-activating factor acetylhydrolase, isoform Ib, PAFAH1B1 or lissencephaly 1 protein (LIS1) and nuclear distribution element-like (NUDEL). We hypothesized that altered expression of DISC1 and/or its molecular partners may underlie its pathogenic role in schizophrenia and explain its genetic association.

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Here we describe the development of a novel specific, rapid ELISA system, which is performed on modified microplates where polyvinylidine fluoride (PVDF) forms the base of each well. The use of microplates with PVDF membranes as the solid phase allows for a greater binding capacity of protein in comparison to the solid phases of traditional ELISAs. The increased binding capacity of the solid phase provides for the direct binding of antigens, which can subsequently be assayed using a single, specific and well-characterized antibody.

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Catechol-O-methyltransferase (COMT) is a key enzyme in the elimination of dopamine in the prefrontal cortex of the human brain. Genetic variation in the COMT gene (MIM 116790) has been associated with altered prefrontal cortex function and higher risk for schizophrenia, but the specific alleles and their functional implications have been controversial. We analyzed the effects of several single-nucleotide polymorphisms (SNPs) within COMT on mRNA expression levels (using reverse-transcriptase polymerase chain reaction analysis), protein levels (using Western blot analysis), and enzyme activity (using catechol methylation) in a large sample (n = 108) of postmortem human prefrontal cortex tissue, which predominantly expresses the -membrane-bound isoform.

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It has been proposed that the therapeutic benefits of treatment with antidepressants and mood stabilizers may arise partially from their ability to stimulate neurogenesis. This study was designed to examine the effects of chronic antipsychotic treatment on cell proliferation and survival in the adult rat hippocampus. Haloperidol (0.

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We examined in the rat, the effects of neonatal (postnatal Day 7) and adult excitotoxic lesions of the mediodorsal thalamus (MDT), a brain area innervating the prefrontal cortex and implicated as a site of neuropathology in schizophrenia. Previous studies showed that rats with neonatal excitotoxic damage of the ventral hippocampus (VH), used as an animal model of this disorder, display in young adulthood a variety of abnormalities reminiscent of schizophrenia, including hyperactivity to stressful stimuli and amphetamine. It has been speculated that behavioral abnormalities of the neonatally VH lesioned animals are mediated through MDT projections to the prefrontal cortex.

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Rats with neonatal excitotoxic damage of the ventral hippocampus display in adulthood a variety of abnormalities reminiscent of schizophrenia and are used as an animal model of this disorder. In the present study, we hypothesized that transient inactivation of ventral hippocampal activity during a critical developmental period may be sufficient to disrupt normal maturation of relevant brain systems and produce similar lasting behavioral changes. We infused tetrodotoxin (TTX) or artificial CSF into the ventral hippocampus on postnatal day 7 (P7) and assessed behavioral changes in response to stress, amphetamine, and (+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine maleate in juvenile (P35) and young adult (P56) rats.

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