Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.99.1 (NADPH-diaphorase)
3,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytochemistry was used to examine the distribution of two pathways of utilization of hydrogen (Type I and Type II H) generated by glucose-6-phosphate dehydrogenase (G6PD) in circumventricular organs (CVOs) and the hypothalamo-neurohypophysial system in cryostat sections of rat brain. Type I H is defined as that portion of the total reducing equivalents (Total H) that is passed, in the intact cells, along the cytochrome chain (NADPH-diaphorase system). In the liver, energy from Type I H is used for cytochrome P-450-dependent oxidation of steroids, as well as xenobiotics. We proposed that mixed function oxidation, and therefore Type I H, would be preferentially localized in brain regions lacking a blood-brain barrier, such as CVOs and magnocellular cells with terminals in such brain regions. Type I H was identified in tissue sections using neotetrazolium. This reagent, when reduced, precipitates as formazan granules that can be quantified. The large difference in redox potential between NADPH and neotetrazolium ensures that only hydrogen (Type I H) passed in the intact cell along the cytochrome chain, can reduce the tetrazole. Total NADPH generation (Total H) from glucose-6-phosphate, was identified using medium containing phenazine methosulphate, a hydrogen acceptor that transfers all reducing equivalents from NADPH to the tetrazole. Type II H, the difference between Total and Type I H, is presumed to be used for NADPH-dependent biosynthetic functions such as lipid synthesis, or reduction of glutathione. In CVOs formazan granules indicative of Type I H were selectively concentrated and localized within cells throughout the SFO, organum vasculosum of the lamina terminalis, pineal gland and in the apical cytoplasm of columnar ependymocytes in the subcommissural organ. Formazan granules attributable to Type I H were also prominent throughout the hypothalamo-neurohypophysial system. Reaction product was present in the cytoplasm of some magnocellular neurons in both the supraoptic and paraventricular nuclei, in the median eminence, including the zona interna, and in and between cells in the neurohypophysis. The distribution of NADPH-diaphorase in sections incubated with NADPH instead of glucose-6-phosphate was similar to that of Type I H. These findings are consistent with the hypothesis that mixed function oxidation involving NADPH and the cytochrome chain occur in these brain regions.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Pathways of hydrogen utilization from NADPH generated by glucose-6-phosphate dehydrogenase in circumventricular organs and the hypothalamo-neurohypophysial system: a cytochemical study. 669 40

Danazol (4 mg/day/animal) and oestradiol-17 beta (100 microgram/day/animal) were administered subcutaneously for 22 and 15 days respectively. The testis and epididymis were histochemically analysed for steroid dehydrogenases, NADH-diaphorase, glucose 6-phosphate dehydrogenase activity and lipids. Both steroids significantly reduced the weights of the testis and other accessory reproductive organs. The activities of delta 5-3 beta- and 17 beta-HSD were markedly reduced in the seminiferous epithelium and interstitial cells of the testis. Sudanophilic lipids accumulated in the seminiferous tubules and the interstitium. Oestradiol generally had a greater effect than did danazol, but both probably affect the testicular function by inhibiting steroidogenesis.
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PMID:A histochemical study of the effect of danazol and oestradiol-17 beta on steroidogenic activity in testis and epididymis of the gerbil, Tatera indica. 693 36

In the early stages of experiments there was a structural-metabolic reconstruction in the adrenal cortex, manifest by changes in interzonal relations and dissociation of the activity of enzymes responsible for energy supply and synthesis of steroid hormones. Analogous changes were also seen later on. However, in the early stages that process was a response to the pancreas injury, whereas in the later period it preceded the emergence of repeated lesions in the gland. In animals with experimental pancreatitis, administration of metapyrone caused an activation of NAD-diaphorase in the glomerular and reticular zones and concurrent potentiation of the activity of glucose-6-phosphate dehydrogenase in all 3 zones of the adrenal cortex.
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PMID:[Histoenzymological characteristics of the adrenal cortical reaction in variants of experimental pancreatitis]. 695 49

Results of histochemical study of testicular tissue in 31 patients, aged 2.5 to 31 years, suffering from dysgenesia syndrome of the testis are presented. Enzymes and lipids furnishing synthesis of steroid hormones (3-beta-oxysteroid dehydrogenase, alcohol dehydrogenase, glucose-6-phosphate dehydrogenase. NAD- and NADP-diaphorase, cholesterol and its esters) were revealed in Leydig's cells of pubertal-juvenile and adult patients, in Leydig's cells precursors in children, and also in Sertoli's cells of all these patients. All these cellular elements possessed high activity of the enzymes under study. It is suggested that Sertoli cells and Leydig's cells precursors, along with mature Leydig's cells, provide a sufficiently high functional activity of the gonads in patients with dysgenesia of the testis.
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PMID:[Functional activity of gonadal glandular cells in patients with testicular dysgenesis]. 699 Apr 2

1. This report describes selected histochemical and physiological properties of the motor units of adult cat soleus muscle approximately one year after self- and cross-reinnervation with the nerve of the heterogenous flexor hallucis longus (f.h.l.). Self-reinnervated f.h.l. motor units are also considered. Whole muscles were tested for fibre reaction to alkaline pre-incubated ATPase, alpha-glycerophosphate dehydrogenase (alpha-GPD) and reduced nicotinamide adenine dinucleotide diaphorase (NADH-D). Motor units were isolated and studied by splitting the ventral root in acute preparations.2. The histochemical fibre type profile in the self-reinnervated muscle was comparable to normal muscle as was mean twitch contraction time, twitch-tetanus ratio and fatigue index. The mean tetanic tension of the soleus self- and cross-reinnervated motor units appeared close to a normal soleus whereas the mean tetanic tension of the f.h.l. self-reinnervated units was significantly less than a normal f.h.l.3. An average of 14% of the fibres of the soleus cross-reinnervated muscles had high ATPase and a alpha-GPD staining intensity in contrast to normal and self-reinnervated soleus in which such fibres are absent. Thus alkaline lability of myofibrillar ATPase increased in some fibres of what was originally a homogeneous population. The small increase in the number of densely staining fibres for ATPase at an alkaline pH (14%) was associated with a 73% decrease in (mean) contraction time (41 +/- 11 ms) of the thirty-three cross-reinnervated muscle units studied, with no unit's contraction time greater than 60 ms. Mean contraction times for the self-reinnervated soleus and f.h.l. muscles were 78 +/- 31 ms and 27 +/- 8 ms respectively.4. All fibres of the soleus cross-reinnervated muscles showed intense reaction to NADH-D, as was true of self-reinnervated soleus. This staining pattern is typical of normal soleus. In concordance, these motor units consistently demonstrated a high resistance to fatigue when stimulated for a four-minute period.5. These results suggest that in the adult self-and cross-reinnervated soleus muscle, there is some active mechanism which regulates the eventual size of motor units as reflected by tetanic tension.6. Change in contraction time from that typical for a soleus unit to that similar to an f.h.l. unit remains incomplete one year after cross-reinnervation. Within this time this partial change in single motor units reflects incomplete neural control of this property rather than a mixture of self- and foreign-innervation.7. A greater degree of independence from neural control to conversion of the histochemically demonstrated myofibrillar ATPase activity exists than is the case for contraction time.
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PMID:Histochemical and physiological properties of cat motor units after self-and cross-reinnervation. 715 31

The epithelia of the respiratory and gastrointestinal tract and their appendages contain a distinct population of disseminated epithelial cells called brush cells or caveolated cells. On the basis of their structure, it was suggested that brush cells might serve as chemo- or volume receptors that play a role in certain aspects of gastrointestinal and bronchopulmonary secretion or motility. In the present study we provide first clues to a possible function of this widespread epithelial cell type. Brush cells of the rat gastric cardia and major pancreatic duct display strong immunoreactivity for nitric oxide synthase (NOS) and also exhibit high activity of NADPH-diaphorase. This NADPH-oxidizing activity was previously shown to be mediated by a specific domain of the sequence of the NOS. NADPH, in turn, appears to be delivered by glucose-6-phosphate dehydrogenase, which we found in brush cells at particularly high levels. We conclude that brush cells of the stomach and pancreas may represent a specialized population of paracrine cells that use nitric oxide as a messenger molecule to control certain gastrointestinal functions.
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PMID:Nitric oxide synthase and NADP-linked glucose-6-phosphate dehydrogenase are co-localized in brush cells of rat stomach and pancreas. 752 87

In normal erythrocytes, small quantities of methaemoglobin are formed constantly and are continuously reduced, almost entirely by the reduced nicotine adenine dinucleotide (NADH) diaphorase system, rather than the reduced nicotine adenine dinucleotide phosphate (NADPH) diaphorase system. Methaemoglobinaemias are usually the result of xenobiotics, either those that may directly oxidise haemoglobin or those that require metabolic activation to an oxidising species. The most clinically relevant direct methaemoglobin formers include local anaesthetics (such as benzocaine and, to a much lesser extent, prilocaine) as well as amyl nitrite and isobutyl nitrite, which have become drugs of abuse. Indirect, or metabolically activated, methaemoglobin formation by dapsone and primaquine may cause adverse reactions. The clinical consequences of methaemoglobinaemia are related to the blood level of methaemoglobin; dyspnoea, nausea and tachycardia occur at methaemoglobin levels of > or = 30%, while lethargy, stupor and deteriorating consciousness occur as methaemoglobin levels approach 55%. Higher levels may cause cardiac arrhythmias, circulatory failure and neurological depression, while levels of 70% are usually fatal. Cyanosis accompanied by a lack of responsiveness to 100% oxygen indicates a diagnosis of methaemoglobinaemia, which should be confirmed using a CO-oximeter. Pulse oximeters do not detect methaemoglobin and may give a misleading impression of patient oxygenation. Methaemoglobinaemia is treated with intravenous methylene blue (methyl-thioninium chloride; ;1 to 2 mg/kg of a 1% solution). If the patient does not respond, perhaps because of glucose-6-phosphate dehydrogenase (G6PD) deficiency or continued presence of toxin, admission to an intensive care unit and exchange transfusion may be required. Dapsone-mediated chronic methaemoglobin formation can be reduced by coadministration of cimetidine to aid patient tolerance. Increasing knowledge and awareness of drug-mediated acute methaemoglobinaemia among physicians should lead to prompt diagnosis and treatment of this potentially life-threatening condition.
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PMID:Drug-induced methaemoglobinaemia. Treatment issues. 882 17

In the central nervous system nitric oxide appears to be critically involved in a number of physiological and pathological processes. Although there is convincing evidence for expression of nitric oxide synthase in cultured glial cells, demonstration of this enzyme in glial cells in situ remained largely unsatisfactory. In the present study we applied immunostaining to freeze-dried sections of snap-frozen hippocampi and cerebella of rats and to sections of freeze-dried brain tissue in order to minimize diffusion artefacts and thus to obtain more precise information about the true in situ localization of nitric oxide synthase. Here we show that astrocytes and Bergmann glia react strongly with antibodies raised against cerebellar nitric oxide synthase and against a type I nitric oxide synthase-specific C-terminal peptide, respectively. This finding was further substantiated by histochemical localization of NADPH-diaphorase activity in astrocytes and Bergmann glia as well as by immunoreactivity of both types of glia cells with antibodies to the NADPH-delivering enzyme glucose-6-phosphate dehydrogenase. We conclude, that astrocytes are important sites of nitric oxide synthase I in brain, suggesting that these cells might use nitric oxide as gaseous messenger molecule for various aspects of glia-neuron signalling.
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PMID:Astrocytes and Bergmann glia as an important site of nitric oxide synthase I. 892 3

The dorsal root ganglion (DRG) neurons were classified in the rat on the basis of their metabolic enzyme properties as determined by quantitative analysis in histochemical staining. In particular, nicotinamide adenine dinucleotide-diaphorase (NADH-d) and alpha-glycerophosphate dehydrogenase (alpha-GPD) activities were examined on two serial sections from the same neurons in the lumbar (L4) DRG. The DRG neurons were classified into three groups based on the soma diameter distribution; small, intermediate and large size DRG neurons. The NADH-d activity showed a unimodal distribution in all size groups, while the alpha-GPD activity clearly showed a bimodal distribution in the intermediate and large size neurons, but not in the small size neurons.
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PMID:Metabolic properties of the sensory neurons in the rat dorsal root ganglion. 917 28

Rabbits given 1 ppm of vanadate in drinking water for twelve months showed (a) increased plasma levels of catecholamines (b) reduction of the arterial concentration of nitric oxide (c) lower activity of urine kallikrein and higher activities of urine kininases I and II and enkephalinase (d) reduced cardiac inotropism and augmented total peripheral resistance, with unchanged blood pressure levels (e) accumulation of the metal in the aorta and cardiac ventricles. Monoaminooxidase and glucose-6-phosphate dehydrogenase activities were increased by vanadate in both kidney and liver and that of NADH-diaphorase in the kidney, in which NADPH-diaphorase activity was reduced. Some of the above results were also obtained in rats given 10 and 40 ppm of vanadate in drinking water for six-seven months; these animals showed arterial hypertension and reduced activity of Na, K-ATPase in the kidney. Vanadium appears to act on the cardiovascular function through selective neurohumoral, autacoidal and transductional mechanisms only in part depending on the species.
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PMID:[Neurohumoral, autacoid and transductional mechanisms in the cardiovascular effects of vanadate: histochemical correlations]. 937 36


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