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Biomedical subjects

I Nagy

Publications and source records attributed to I Nagy.

At least 109 records · Page 6Linked to original sources
PubMed1994

Sequence of Rhodococcus gene cluster encoding the subunits of ethanolamine ammonia-lyase and an APC-like permease.

Sequence analysis of a 5173-bp genomic fragment from the nocardioform actinomycete Rhodococcus sp. strain NI86/21 revealed the presence of two genes, eutB and eutC, encoding the putative homologues of the large and small subunits of the ethanolamine ammonia-lyase, respectively, from Salmonella typhimurium. This is the first report of the characterization of these genes in a Gram-positive species. Immediately upstream of eutB, a gene encoding a putative permease of the APC (amino acids, polyamines, choline) transporter family was located. At present, no other Gram-positive members of this permease family are known. The translational coupling of these eut genes suggests an operon-like organization of the ethanolamine genes in Rhodococcus species. A truncated open reading frame downstream of eutC contained an N-terminal motif characteristic of membrane-anchored lipoproteins.

Amino Acid Sequence↗
PubMed1994

Sympathetic-adrenergic activity and acid-base regulation under acute physical stress in type I (insulin-dependent) diabetic children.

To evaluate the efficacy of the acute-physical-stress response, plasma catecholamine and lactate levels, serum electrolytes, fructosamine, blood glucose and acid-base status were measured in insulin-dependent diabetes mellitus (IDDM) children and the data compared to those of healthy controls. Four groups were studied: group 1, healthy controls; group 2, newly diagnosed diabetic patients with an IDDM duration of 2-4 weeks; group 3, with an IDDM duration of 5-7 years; group 4, with an IDDM duration of 10-13 years. According to their fructosamine levels, IDDM children were in a well-controlled metabolic state. The physical stress was induced by 1.5-1.7 W/kg/10 min bicycle ergometer determined by a target pulse rate of 170/min. IDDM children exhibited pronounced lactic acidosis under stress (pH: group 2, 7.27 +/- 0.07; group 3, 7.28 +/- 0.05; group 4, 7.20 +/- 0.04, vs. group 1; 7.34 +/- 0.03). Baseline plasma norepinephrine and epinephrine levels showed a significant decrease parallel to the duration of IDDM. Stress induced an increase in the concentration of norepinephrine in each group, but the elevation was significantly higher in the IDDM children versus the controls. A significant negative correlation was found between pH and maximal plasma norepinephrine levels (y = 7.3-0.006x, r = -0.46, p < 0.02). Stress resulted in blood glucose elevation in 13 patients regardless of their pre-exercise blood glucose levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1993

Comparative drug influence on peroxide mediated increase of cytosolic calcium in human endothelial cells.

The increase of cytosolic free calcium in human umbilical vein endothelial cells caused by peroxides was used as a model to determine and compare the putative cytoprotective properties of substances known to interfere with the generation or metabolism of reactive oxygen species. Hydrophilic hydrogen peroxide and lipophilic cumene hydroperoxide were used as sources of reactive oxygen. [Ca2+]i in endothelial cells was measured by the FURA method and the resting level was found to be 129.3 +/- 14.1 nM. Both peroxides were found to increase cytosolic calcium with dependence on the concentration and on the presence of extracellular calcium. Among the substances tested, only catalase and N-acetyl-cysteine were able to exhibit a significant cytoprotective effect.

Antioxidants↗
PubMed1993

[Diagnosis of Verner-Morrison syndrome (VDHA) and its treatment with sandostatin an streptozocitin].

A case report is presented of a man with Verner-Morrison syndrome of extreme severity, caused by an unresectable pancreatic VIPoma. The pathological role of vasoactive intestinal polypeptide (VIP) is discussed in the pathogenesis of Watery Diarrhoea, Hypokalaemia, Achlorhydria (WDHA) syndrome. The authors describe the typical symptoms of the syndrome and provide a diagnostic and therapeutic strategy. Plasma level of VIP was determined by the authors' own VIP RIA method. Administration of a long acting somatostatin analogue, octreotide (Sandostatin, Sandoz) at a dose of 100 micrograms daily, decreased the plasma level of VIP from about 55 to 38 fmol/ml, which was associated with complete regression of the diarrhoea. Due to the 'escape phenomenon' the dose of Sandostatin was gradually increased and finally completed with streptozotocin (Zanosar, Upjohn) administration, which was repeated every 8 weeks. The combination of Sandostatin and streptozotocin resulted in complete regression of diarrhoea and substantial diminution of the tumour mass. The patient displayed a weight gain and returned to normal life.

Humans↗
PubMed1993

Morphological and membrane properties of young rat lumbar and thoracic dorsal root ganglion cells with unmyelinated axons.

Membrane and morphological properties of thoracic (Th9-13) and lumbar (L2-5) dorsal root ganglion cells have been investigated in an in vitro dorsal root ganglion (DRG) preparation from 14-day-old rats using intracellular recordings and the intracellular injection of Neurobiotin. The passive and active membrane properties of 47 DRG cells with conduction velocities (CV) less than 0.81 m/s were studied, which were considered to possess unmyelinated axons. The action potentials elicited by the stimulation of peripheral nerves or the dorsal roots were characteristic of C-cells, with long duration, inflexion on the falling phase and long lasting after hyperpolarization. Input resistance of the C-cells varied between 16 and 158 M omega and were significantly higher in thoracic than in the lumbar ganglia. Cells in the more cranial levels also tended to be smaller than those in the caudal levels with a mean cross sectional area of 301 +/- 32.5 microns2. Twenty-five percent of the cells from both regions showed an inward rectification. The distribution of CVs, input resistances and cross sectional areas were non-normal. While a weak correlation was found between the conduction velocity and input resistance of the cells, no correlation was present between the size of the perikarya and conduction velocity or the input resistance. These results show that by the 14th day of postnatal development membrane and morphological parameters approach those of adult rats. They also suggest that in cells with unmyelinated fibres, the size of the perikaryon does not predict the thickness of the axon, and that this cell population is heterogeneous.

Action Potentials↗
PubMed1993

[Management of chronic venous insufficiency with the combination of coumarin (Syncoumar) and oral pentosan polysulfate (PPS, SP 54) (preliminary report)].

Fibrinolysis of 19 patients who developed CVI after deep vein thrombosis was examined. Mean age of patients at the first thrombosis was 31.8 years. For testing fibrinolysis fibrinogen, plasminogen, AP, ECLT, with venous occlusion were determined. In 10 patients t-PA and PAI-1 activities were also measured and plethysmography was carried out. For screening blood coagulation abnormalities of TCT count, PT, APTT, TT, AT III, protein C were tested. The common abnormality was the decreased fibrinolysis. Patients had been on coumarin for 6.14 years before entering the study. Under coumarin treatment 6 patients had relapsed DVT, 4 had crural ulcer and CVI deteriorated in 8 patients. Therefore we added fibrinolysis increasing PPS to coumarin. PPS dose was individually determined by PPS loading test (150-500 mg). Mean observation time with the combined treatment was 2.92 years. Clinical check up and fibrinolysis test were carried out every 6 months. Clinical improvement occurred in 13 patients, (decrease of swelling, pain etc). Two out of 4 patients with stasis ulcer experienced complete healing; in 1 the ulcer territory diminished in size. Maximum venous outflow improved in 7 patients, 3 patients were non-responders. We observed an increase of fibrinolysis in 10 patients. Venous occlusion enhanced the fibrinolysis increasing effect of PPS. The activity reached its maximum by the first control. The fibrinolysis increase and the clinical improvement do not always run parallel, therefore other effects of PPS as the reason for being beneficial in CVI must be considered (antiinflammatory, ect.). Combination of coumarin and PPS seems to be an effective therapy in CVI with decreased fibrinolysis.

Acenocoumarol↗
PubMed1993

Effects of the antioxidant butylated hydroxyanisole on cytosolic free calcium concentration.

The effect of the antioxidant butylated hydroxyanisole on free intracellular calcium was investigated in rat cardiomyocytes, rat pituitary cells, human umbilical vein endothelial cells, granulocytes and BHK-cells. The effects of incubation time and butylated hydroxyanisole (BHA) concentrations were examined with respect to the extracellular calcium concentration. Butylated hydroxyanisole increased the free cytosolic calcium concentration in a dose- and time-dependent manner irrespective of the presence of extracellular calcium. Differences between all cell types were observed in the sequel of the re-uptake of the calcium ions released by BHA. Dependence on the concentration of extracellular calcium on the extent of sequestration was seen in rat pituitary cells and cardiomyocytes only.

Animals↗
PubMed1993

Pancreatic trophism in experimental liver cirrhosis.

Pancreatic trophism and pancreatic enzyme composition, and plasma levels of cholecystokinin, insulin, glucagon, and glucose in liver cirrhosis induced by chronic thioacetamide administration (0.02% in the drinking water for 12 mo) were studied in rats. Advanced liver cirrhosis was evident in all thioacetamide-treated rats. The weight of the pancreas and its contents of DNA, protein, trypsinogen, chymotrypsinogen, proelastase, secretory trypsin inhibitor, and amylase were significantly increased as compared to the controls. The pancreatic secretory enzyme content changes showed a nonparallelism, characteristic of a cholecystokinin effect. Light and electron microscopy revealed a normal pancreatic architecture. Bioassayed plasma cholecystokinin levels in both fed and 24-h-fasted cirrhotic rats were significantly higher than in the corresponding controls. The plasma glucose, insulin, and glucagon levels demonstrated hypoglycemic tendencies with a glucagon predominance. These findings indicate that advanced liver cirrhosis in the rat is accompanied by pancreatic hypertrophy and hyperplasia, which might be attributed, at least in part, to elevated circulating cholecystokinin levels.

Animals↗
PubMed1993

The role of neurokinin and N-methyl-D-aspartate receptors in synaptic transmission from capsaicin-sensitive primary afferents in the rat spinal cord in vitro.

The rat spinal cord with connected dorsal root ganglia was used to study neurokinin and N-methyl-D-aspartate receptors involved in the sensory synaptic transmission of dorsal horn cells. Selective C-fibre excitation was produced by capsaicin (200-500 nM) administered to the dorsal root ganglions. Sixty-nine per cent of dorsal horn cells responded with a postsynaptic depolarization and enhanced synaptic activity, recorded via intracellular electrodes, to capsaicin-activated primary afferent input. Dorsal horn neurons activated by the capsaicin-evoked input were also excited by a 1-min perfusion of the neurokinin-1 receptor agonists substance P methyl ester or GR73 632 and by the neurokinin-2 agonist neurokinin-A. These cells were also depolarized by N-methyl-D-aspartate. Responses to substance P methyl ester and GR73 632 were selectively reduced by the neurokinin-1 receptor antagonist CP96,345, and responses to neurokinin-A were completely blocked by the neurokinin-2 receptor antagonist MEN10 376. The depolarization evoked by N-methyl-D-aspartate was not altered by either of the antagonists, but was completely blocked by the selective N-methyl-D-aspartate receptor antagonist (-)-2-amino-5-phosphonovaleric acid. Capsaicin-evoked responses in the dorsal horn were inhibited by MEN10,376 (63 +/- 13% inhibition) but no significant change was observed with CP96,345. The N-methyl-D-aspartate receptor antagonist (-)-2-amino-5-phosphonovaleric acid consistently inhibited the capsaicin-induced response by 76 +/- 14%. Combination of (-)-2-amino-5-phosphonovaleric acid and MEN10,376 produced an almost complete abolition of the capsaicin-evoked depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1993

Cobalt uptake enables identification of capsaicin- and bradykinin-sensitive subpopulations of rat dorsal root ganglion cells in vitro.

A novel modification of the stimulated cobalt uptake technique has been used to identify rat dorsal root ganglion cells expressing capsaicin and bradykinin receptors. The technique involves incubating intact dorsal root ganglia in vitro in a modified Krebs solution in which cobalt chloride has been substituted for calcium. Activation of dorsal root ganglion cells by capsaicin or bradykinin in the presence of the cobalt ions results in cobalt influx into the excited cells. Histochemical methods were then used to visualize the intracellular accumulation of cobalt, and labelled cells were counted and characterized. Capsaicin (2 microM) or bradykinin (500 nM) applied for 20 min induced cobalt uptake in 13.8 +/- 0.6 and 9.6 +/- 0.5% of neuronal profiles in dorsal root ganglia (L4), respectively, a significantly larger number than stained in control ganglia (in the absence of agonists: 1.8 +/- 0.7%). The longest diameter of the soma of stained dorsal root ganglion cells following capsaicin and bradykinin perfusion were significantly different from each other and from the non-labelled population (17.5 +/- 0.7 and 24.5 +/- 0.2 microns for capsaicin; 23.2 +/- 0.9 and 25.5 +/- 0.4 microns for bradykinin; labelled and non-labelled cells, respectively). The distribution of cell diameters revealed that while capsaicin-sensitive cells were exclusively small-sized, bradykinin-sensitive cells were predominantly small and medium sized. The selective bradykinin-2 receptor antagonist HOE-140 (5.0 microM) blocked the bradykinin-induced staining (2.16 +/- 0.02%) but not that of capsaicin. The bradykinin-1 agonist [des-Arg9]-bradykinin did not induce any significant increase in stained cells over the control number (2.2 +/- 0.7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Comparison of the lateral diffusion constant of hepatocyte membrane proteins in two wild mouse strains of considerably different longevity: FRAP studies on liver smears.

The liver cells of male and female wild mice (Peromyscus leucopus and Mus musculus) have been studied in young, adult, and old age groups. Because P. leucopus displays a life expectancy of 7-8 years, the age groups of this strain were from 5.5 to 68 months. M. musculus survives only to about 2.5 years; therefore, the age groups of this strain ranged from 6 to 27 months. Protein lateral diffusion in hepatocyte membranes was measured by means of fluorescence recovery after photobleaching (FRAP) in liver smears. The peroxide-induced autofluorescence was utilized as a fluorescent label, which in H2O2 treated liver smears is caused by the oxidation of riboflavin bound uniformly to all proteins of the cell membrane. This way the average lateral diffusion constant (D) and the fractional recovery of those proteins can be measured. In both males and females of both strains D displayed a negative linear age correlation. Intraspecies sex differences were small and statistically insignificant. However, interspecies comparisons of males or females resulted in a strongly significant difference: although the intercept points of the regression lines describing D were identical in both strains (3.1 x 10(-10) cm2/sec), the decay of D with aging was about 2.5 times faster in the short-living M. musculus than in the long-living P. leucopus. By the end of life expectancy, both strains reached practically identical values (about 1.9 x 10(-10) cm2/sec). The results lend further support to the membrane hypothesis of aging.

Aging↗
PubMed1993

gamma-Aminobutyric acid-induced elevation of intracellular calcium concentration in pituitary cells of neonatal rats.

Gamma-aminobutyric acid (GABA) increased intracellular calcium concentration ([Ca2+]i) of newborn rat pituitary cells in suspension measured by the FURA-2 method. The effect of GABA was dose dependent in the range of 0.1-10 microM. This effect diminished with postnatal age as measured at days 2, 14 and 21, and in adult animals. The GABA stimulation was mimicked by muscimol; in contrast, baclofen (up to 100 microM) was ineffective. Picrotoxin, a GABAA antagonist interacting with GABA-activated chloride ionophores, caused a dose-dependent inhibition of the [Ca2+]i elevating effect of 100 microM GABA or muscimol. These observations indicate the involvement of GABAA type receptors. The GABA or muscimol effect on [Ca2+]i was antagonized by nifedipine (10 microM) or verapamil (50 microM), and completely abolished in the presence of 4 mM EGTA (low-calcium medium). The findings indicate the presence of depolarizing GABAA receptors on neonatal rat pituitary cells. It seems very likely that the mechanism by which GABA receptor occupation results in elevated [Ca2+]i is a membrane depolarization by increased Cl- conductance followed by calcium influx through L-type voltage-dependent calcium channels.

Animals↗
PubMed1992

Sequence of a Rhodococcus gene encoding a protein with extensive homology to the mammalian propionyl-CoA carboxylase beta chain.

Sequence analysis of a 2-kilobase DNA fragment from Rhodococcus sp. NI86/21 revealed an open reading frame encoding a 476-amino-acid protein with striking homology to the rat and human propionyl-CoA carboxylase beta subunits. The nucleotide sequence of a corresponding prokaryotic gene has not yet been reported. Upstream, the C-terminal part of a putative beta-ketoacyl synthase was identified.

3-Oxoacyl-(Acyl-Carrier-Protein) Synthase↗
PubMed1992

[Biochemical, clinical and genetic analysis of various aminoacidopathies (non-ketotic hyperglycemia, maple syrup urine disease, histidinemia, tyrosinemia)].

The genetical types were classified according to the clinical findings and biochemical results in cases of 13 newborn/children suffering from various aminoacidopathies. The genetical types were: 3 neonatal and 4 infantile types were found out of 7 non-ketotic disease (MSUD) patient was infantile type with 9.1 per cent keto acid decarboxylase activity in leukocyte homogenate. Among the 3 histidinemic patients 1 was severe neonatal type and 2 cases were chronic types. The 2 treated tyrosinemic children proved to be type III. (chronic with rickets).

Amino Acid Metabolism, Inborn Errors↗
PubMed1992

[Experience with surgical treatment of ascendant varicophlebitis].

In ascendant varicophlebitis, the authors suggest not only crossectomy, but also radical removal of the dilated part of the great saphenous vein and of all thrombosed and non-thrombosed varicose veins in one session. They consider it important to clear the extension of the thrombosis by using an ultrasonic doppler flowmeter or the duplex scan technique; phlebography is needed only if deep venous affection is suspected. Cardinal questions of the operative technique are discussed. In cases of deep venous affection, thrombectomy is performed with Fogarty catheter. Antibiotics are generally held to be unnecessary, but early mobilisation and postoperative low-dose heparin prophylaxis are of great importance. No significant complications were detected after 37 interventions. Every patient was controlled one year after surgery. Residual complaints were found more rarely in the radically treated group. As concerns the quick and definitive recovery, mention is made of favourable economic consequences of the active surgical treatment.

Femoral Vein↗