Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myelinating Schwann cells express the gap junction protein, connexin (Cx)32, which is present at the nodes of Ranvier and Schmidt-Lantermann incisures (Bergoffen et al. [1993] Science (Wash. ) 262:2039-2042). Following peripheral nerve injury, other members of the connexin gene family are also expressed (Chandross et al. [1996a] Mol. Cell. Neurosci. 7:501-518). This study surveys the connexin(s) expressed by rat sciatic nerve, cultured Schwann cells, and a mouse Schwannoma (TR6 Bc1) cell line. Reverse transcriptase-polymerase chain reaction (RT-PCR) amplification revealed a constitutive expression of mRNA encoding Cx32 and 43 but not Cx26, 37, 40, 45, and 46 in sciatic nerve. Mitogenic stimulation of cultured Schwann cells expressing Cx32 also resulted in the appearance of Cx43 mRNA. Schwannoma cells expressed exclusively Cx43 mRNA. These results were confirmed by Northern blot analysis. Functional gap junctions in cultured Schwann and Schwannoma cells were shown by analysis of the intercellular transfer of Lucifer yellow, although the coupling between primary Schwann cells was weak or undetectable. Treatment of primary Schwann cells with mitogens resulted in extensive dye coupling. An immunohistochemical study of adult sciatic nerve sections demonstrated Cx32 immunoreactivity at the nodes of Ranvier and in Schwann cell bodies. Lower intensity staining of Cx43 along the myelin sheath and Schwann cell bodies was also observed. Indirect immunofluorescent studies of Schwann cells treated with mitogens showed characteristic punctate cell surface staining of Cx43; Cx32 staining was detected mainly intracellularly. These results lead to the conclusion that in addition to the expression of Cx32 by normal adult sciatic nerve, low amounts of Cx43 protein are also present. The implications of the expression of two connexins by Schwann cells in Charcot-Marie-Tooth X-linked disease, a demyelinating peripheral neuropathy, are discussed.
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PMID:Multiple connexin expression in peripheral nerve, Schwann cells, and Schwannoma cells. 1039 94

The safety and efficacy of hydroxyurea with didanosine in combination with stavudine in nucleoside reverse-transcriptase inhibitor (NRTI)-experienced patients was investigated. Entry criteria included HIV-1 infected, NRTI-experienced adults, with CD4(+) counts 50-550 cells/mm(3) and viral loads >or=12,500 copies/mL. Subjects were treated with didanosine 200 mg twice a day (BID), stavudine 40 mg BID, and hydroxyurea 1000 mg daily for 16 weeks. Thirty-one HIV-1 subjects with mean bDNA viral load 1x10(5) log(10) copies/mL and mean CD4(+) T-cell counts of 231 cells/mm(3) were enrolled. A 1.3 log(10) decrease in mean viral load was seen at 12 weeks of therapy. Prior didanosine use resulted in a more rapid response to therapy compared with prior zidovudine use. Side effects consisting of neutropenia, pancreatitis, and peripheral neuropathy occurred in four subjects and resolved upon withdrawal of therapy. This non-randomized study in subjects with a mean CD4(+) T-cell count of 230 cells/mm(3) demonstrates the antiviral activity of hydroxyurea+didanosine and stavudine. Toxicities related to therapy need to be followed closely. The results support the need for a randomized, prospective study to determine the safety and efficacy of hydroxyurea plus didanosine in antiretroviral-experienced patients with CD4(+) cell counts below 300 cells/mm(3).
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PMID:Hydroxyurea in combination with didanosine and stavudine in antiretroviral-experienced HIV-infected subjects with a review of the literature. 1280 44

Essential mixed cryoglobulinemia (type II) has turned out to be secondary to hepatitis C virus (HCV) infection in the large majority of patients. Interferon might be anticipated to be effective only in HCV-associated cryoglobulinemias. We found that interferon was highly effective in an HCV-positive patient with true essential type II mixed cryoglobulinemia. The patient presented with symptomatic cryoglobulinemic vasculitis without underlying immunologic, infectious, or neoplastic diseases. Tests for HCV viremia, a reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay, and anti-HCV antibodies (third-generation assays) were positive before therapy. The patient had severe cryoglobulinemic vasculitis with purpura, peripheral neuropathy, and membranous proliferative glomerulonephritis. The cryocrit before therapy was 6 percent in the patient. Recombinant interferon alfa-2a (Roferon-A, Hoffmann-LaRoche, Basel, Switzerland) was administered at a dose of 3 million units per day for three months and 3 million units every other day for the subsequent nine months, a protocol adopted for HCV-associated cryoglobulinemia. The patient had a complete clinical response, with the disappearance of serum cryoglobulins and all signs of cutaneous vasculitis and with the normalization of kidney-function results and urinary values in the patient with nephropathy. The patient has remained in complete remission for more than one year since the withdrawal of therapy. True essential mixed cryoglobulinemia with HCV infection complicated with glomerulonephritis represents a therapeutic challenge.
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PMID:Hepatitis C virus-associated type II mixed cryoglobulinemia vasculitis complicated with membranous proliferative glomerulonephritis. 1921 13

Peripheral neuropathy is an important complication of antiretroviral therapy. Nucleoside reverse-transcriptase inhibitor (NRTI)-associated mitochondrial dysfunction, inflammation and nutritional factors are implicated in its pathogenesis. Pharmacogenetic and genomic studies investigating NRTI neurotoxicity have only recently become possible via the linkage of HIV clinical studies to large DNA repositories. Preliminary case-control studies using these resources suggest that host mitochondrial DNA haplogroup polymorphisms in the hemochromatosis gene and proinflammatory cytokine genes may influence the risk of peripheral neuropathy during antiretroviral therapy. These putative risk factors await confirmation in other HIV-infected populations but they have strong biological plausibility. Work to identify underlying mechanisms for these associations is ongoing. Large-scale studies incorporating clearly defined and validated methods of neuropathy assessment and the use of novel laboratory models of NRTI-associated neuropathy to clarify its pathophysiology are now needed. Such investigations may facilitate the development of more effective strategies to predict, prevent and ameliorate this debilitating treatment toxicity in diverse clinical settings.
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PMID:Pharmacogenetics of nucleoside reverse-transcriptase inhibitor-associated peripheral neuropathy. 1937 18

Susceptibility to peripheral neuropathy during antiretroviral therapy with nucleoside reverse-transcriptase inhibitors was previously associated with a European mitochondrial DNA (mtDNA) haplogroup among non-Hispanic white persons. To determine whether nucleoside reverse-transcriptase inhibitor-associated peripheral neuropathy was related to mtDNA variation in non-Hispanic black persons, we sequenced mtDNA of participants from AIDS Clinical Trials Group study 384. Of 156 non-Hispanic black persons with genomic data, 51 (33%) developed peripheral neuropathy. In a multivariate model, African mtDNA subhaplogroup L1c was an independent predictor of peripheral neuropathy (odds ratio, 3.7 [95% confidence interval, 1.1-12.0]). An African mtDNA subhaplogroup is for the first time implicated in susceptibility to nucleoside reverse-transcriptase inhibitor-associated toxicity.
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PMID:African mitochondrial DNA subhaplogroups and peripheral neuropathy during antiretroviral therapy. 2040 93

To investigate neurochemical changes associated with bortezomib-induced painful peripheral neuropathy (PN), we examined the effects of a single-dose intravenous administration of bortezomib and a well-established "chronic" schedule in a rat model of bortezomib-induced PN. The TRPV1 channel and sensory neuropeptides CGRP and substance P (SP) were studied in L4-L5 dorsal root ganglia (DRGs), spinal cord, and sciatic nerve. Behavioral measures, performed at the end of the chronic bortezomib treatment, confirmed a reduction of mechanical nociceptive threshold, whereas no difference occurred in thermal withdrawal latency. Western blot analysis showed a relative increase of TRPV1 in DRG and spinal cord after both acute and chronic bortezomib administration. Reverse transcriptase-polymerase chain reaction revealed a decrease of TRPV1 and CGRP mRNA relative levels after chronic treatment. Immunohistochemistry showed that in the DRGs, TRPV1-, CGRP-, and SP-immunoreactive neurons were mostly small- and medium-sized and the proportion of TRPV1- and CGRP-labeled neurons increased after treatment. A bortezomib-induced increase in density of TRPV1- and CGRP-immunoreactive innervation in the dorsal horn was also observed. Our findings show that bortezomib-treatment selectively affects subsets of DRG neurons likely involved in the processing of nociceptive stimuli and that neurochemical changes may contribute to development and persistence of pain in bortezomib-induced PN.
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PMID:Bortezomib treatment produces nocifensive behavior and changes in the expression of TRPV1, CGRP, and substance P in the rat DRG, spinal cord, and sciatic nerve. 2487 63

There are four classes of antiretroviral agents used in the treatment of HIV/AIDS. Adverse effects to Highly Active Antiretroviral Therapy (HAART) are common and often difficult to avoid. In many cases, research is not able to identify the exact cause of an adverse event. The severity of adverse reactions varies greatly and difficult to manage; typically prevention is more desirable than treatment. However, this is not always true. This paper will review safety aspect of class-wide Highly Active Antiretroviral Therapy, mechanism of action. A class-wide adverse effect for Reverse transcriptase inhibitors includes lactic acidosis, peripheral neuropathy and lipoatrophy. Class wide adverse effects to non-nucleoside reverse transcriptase inhibitors include rash and hepatotoxicity, while efavirenz has its own unique CNS reactions. Protease inhibitor side effects include hyperglycemia, lipoaccumulation, dyslipidemia, and gastrointestinal (GI) intolerance. Coreceptor CCR5 antagonists, which provide a novel mechanism of action, are a recent addition to the armamentarium of antiretroviral agents. Antiretroviral are an important break-through in the treatment of HIV/AIDS. However, adverse reactions from these drugs can range from mild to life-threatening, and determining which agent is the cause is frequently difficult to discern. Fortunately, side effects can be monitored, treated and in many cases, prevented.
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PMID:Safety Aspects of Antiretroviral Therapy for Management of HIV Infection. 2520 54

Oxygen free radical damage is regarded as a direct or indirect common pathway associated with diabetic neuropathy and is the main cause of complications in peripheral neuropathies. We speculate that Jiaweibugan decoction has a significant effect in treating diabetic peripheral neuropathy through an anti-oxidative stress pathway. In this study, a diabetic rat model was established by intraperitoneal injection of streptozotocin. Rats were treated with Jiaweibugan decoction via intragastric administration. The levels of malondialdehyde and glutathione, which are indirect indexes of oxidative stress, in serum were determined using a colorimetric method. The expression levels of nuclear factor kappa B p65 mRNA and p38 mitogen-activated protein kinase, which are oxidative stress associated factors, in the dorsal root ganglion of spinal S4-6 segments were evaluated by reverse-transcriptase polymerase chain reaction and immunohistochemistry. Results showed that, Jiaweibugan decoction significantly ameliorated motor nerve conduction velocity in diabetic rats, effectively decreased malondialdehyde levels in serum and the expression of nuclear factor kappa B p65 mRNA and p38 mitogen-activated protein kinase mRNA in the dorsal root ganglion, and increased glutathione levels in serum. Therefore, our experimental findings indicate that Jiaweibugan decoction plays an anti-oxidative stress role in the diabetic peripheral neuropathy process, which has a protective effect on peripheral nerve injury.
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PMID:Protective effect of Jiaweibugan decoction against diabetic peripheral neuropathy. 2520 5

Endocrinopathic laminitis is pathologically similar to the multi-organ dysfunction and peripheral neuropathy found in human patients with metabolic syndrome. Similarly, endocrinopathic laminitis has been shown to partially result from vascular dysfunction. However, despite extensive research, the pathogenesis of this disease is not well elucidated and laminitis remains without an effective treatment. Here, we sought to identify novel proteins and pathways underlying the development of equine endocrinopathic laminitis. Healthy Standardbred horses (n = 4/group) were either given an electrolyte infusion, or a 48-h euglycemic-hyperinsulinemic clamp. Cardiac and lamellar tissues were analyzed by mass spectrometry (FDR = 0.05). All hyperinsulinemic horses developed laminitis despite being previously healthy. We identified 514 and 709 unique proteins in the cardiac and lamellar proteomes, respectively. In the lamellar tissue, we identified 14 proteins for which their abundance was significantly increased and 13 proteins which were significantly decreased in the hyperinsulinemic group as compared to controls. These results were confirmed via real-time reverse-transcriptase PCR. A STRING analysis of protein-protein interactions revealed that these increased proteins were primarily involved in coagulation and complement cascades, platelet activity, and ribosomal function, while decreased proteins were involved in focal adhesions, spliceosomes, and cell-cell matrices. Novel significant differentially expressed proteins associated with hyperinsulinemia-induced laminitis include talin-1, vinculin, cadherin-13, fibrinogen, alpha-2-macroglobulin, and heat shock protein 90. In contrast, no proteins were found to be significantly differentially expressed in the heart of hyperinsulinemic horses compared to controls. Together, these data indicate that while hyperinsulinemia induced, in part, microvascular damage, complement activation, and ribosomal dysfunction in the lamellae, a similar effect was not seen in the heart. In brief, this proteomic investigation of a unique equine model of hyperinsulinemia identified novel proteins and signaling pathways, which may lead to the discovery of molecular biomarkers and/or therapeutic targets for endocrinopathic laminitis.
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PMID:Differential Proteomic Expression of Equine Cardiac and Lamellar Tissue During Insulin-Induced Laminitis. 3259 66