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Biomedical subjects

M Schmidt

Publications and source records attributed to M Schmidt.

At least 775 records · Page 43Linked to original sources
PubMed1986

Mechanism of met oncogene activation.

The met oncogene activated in vitro by treatment of a human osteogenic sarcoma (HOS) cell line with N-methyl-N'-nitronitrosoguanidine (MNNG) is related to the tyrosine kinase gene family. Probes from the met oncogene locus recognize two distinct transcripts of 9.0 kb and 10.0 kb which are independently expressed in a cell-type-specific fashion. While the met proto-oncogene locus expresses the 9.0 kb RNA and maps to human chromosome 7q21-31, the locus expressing the 10.0 kb RNA, (tpr; translocated promoter region) maps to human chromosome 1. Both MNNG-HOS cells and met NIH 3T3 transformants express a novel 5.0 kb RNA which represents a hybrid transcript with 5' sequences derived from tpr and 3' sequences from the met proto-oncogene. Treating HOS cells in vitro with MNNG, a known clastogenic carcinogen, resulted in fusion of two chromosomally disparate loci, met and tpr, generating the active met oncogene.

Cell Line↗
PubMed1986

[Pulmonary functional disorders in ulcerative colitis and Crohn's disease].

Lung functions were tested (by whole-body plethysmography, pneumotachography, CO diffusion, blood-gas analysis) in 54 patients with Crohn's disease, 21 with ulcerative colitis and 43 healthy subjects. Abnormalities of pulmonary function were found in 38% of those with ulcerative colitis and 54% with Crohn's disease, significantly more often (p less than 0.005) than in the healthy controls (7%). Obstructive disorders were more frequent in patients with ulcerative colitis than Crohn's disease (p less than 0.01), the latter having mainly restrictive and diffusion abnormalities. The abnormal results were unrelated to previous drug treatment as well as duration, activity and site of the disease. The cause of the respiratory abnormalities remain unexplained, but they may be extra-intestinal manifestations of ulcerative colitis and Crohn's disease.

Adult↗
PubMed1986

Value of determination of kininase II in bronchoalveolar lavage fluid.

Kininase II (KII), identical with angiotensin-I-converting enzyme (E.C. 3.4.15.1) was characterized biochemically and assayed fluorimetrically in bronchoalveolar lavage fluid and serum of 153 patients with several pulmonary disorders. The albumin concentrations of serum and bronchoalveolar lavage fluid (BLF) have also been measured. The pH optimum of KII derived from BLF (LKII) was 8.0. The Michaelis Menten constant was 38.5 mumol/l using benzyloxycarbonyl-phenylalanyl-histidyl-leucine as synthetic substrate. LKII could be inhibited between 80 and 100% by EDTA, phenanthroline, dimercapto-1-propane-sulfonic acid (DMPS), hydroxyquinoline and captopril. The LKII activity (mU/ml BLF) showed no differences in all lung diseases, but the specific LKII (mU/mg albumin) was significantly elevated in sarcoidosis compared to pneumonia (p less than 0.05), fibrosis (p less than 0.05), chronic obstructive bronchitis (p less than 0.005) and lung cancer (p less than 0.01), but not in tuberculosis. This study shows that LKII is measurable in native, unconcentrated BLF and the results indicate that LKII could be useful for diagnosis of pulmonary disorders.

Bronchi↗
PubMed1986

Kininase I and II activities in serum of patients with lung diseases.

In serum of 530 patients with various lung diseases and in 70 healthy control subjects, kininase I (E.C. 3.4.17.3) and kininase II (E.C. 3.4.15.1) were measured spectrophotometrically using hippuryl-L-arginine for estimation of kininase Ia (KIa), hippuryl-L-lysine for kininase Ib (KIb) and hippuryl-L-histidyl-L-leucine for kininase II (KII). KIa and KIb were significantly elevated (p less than 0.02) in lung cancer and sarcoidosis, compared to tuberculosis and healthy controls. There was an increase (p less than 0.05) in lung cancer in relation to sarcoidosis, chronic obstructive bronchitis, tuberculosis, pulmonary fibrosis and healthy control subjects. KII was significantly elevated in sarcoidosis (p less than 0.0001). According to the histological types of lung cancer, no differences of KIa, KIb and KII have been found. The ratio KIa/KIb X KII was 2.3 in lung cancer and 6.7 in the group with sarcoidosis. These results show that the determination of kininases can be used for diagnosis of lung diseases.

Carboxypeptidases↗
PubMed1986

Immunogenicity of recombinant hepatitis B vaccine in dialysis patients.

Eighty-eight dialysis patients were vaccinated with recombinant hepatitis B vaccine prepared in yeast. Fourty-nine patients were immunized 3 times (months 0, 1, 6) intragluteally with 40 micrograms hepatitis B surface antigen (HBsAg) per dose. Only 32 of them (65.3%) showed anti-HBs concentrations above 10 IU/l with a geometric mean titer (GMT) of 180.7 IU/l after 3 vaccinations, whereas all of the 16 healthy controls, vaccinated 3 times with a 10-micrograms dose of the same vaccine batch, had specific antibodies higher than 10 IU/l (GMT 897.4 IU/l). Responses of patients were slightly higher than those of dialysis patients vaccinated in an earlier study with plasma-derived vaccine according to the same schedule. Results in 20 patients immunized 6 times intragluteally with 40 micrograms HBsAg/dose in monthly intervals were not better (at month 7, 65% showed anti-HBs concentrations greater than 10 IU/l; GMT = 126.6 IU/l), and 19 patients receiving 6 times 20 micrograms HBsAg monthly showed significantly lower responses (anti-HBs greater than 10 IU/l in 42% of vaccinees, GMT = 89.5 IU/l). The vaccine was tolerated well; side-effects were slight, and no serious adverse reactions were observed. In conclusion, recombinant hepatitis B vaccine is comparable to plasma-derived vaccine also in the case of dialysis patients; a 6-dose schedule does not seem to have much advantage compared to the conventional 3-dose regimen.

Adult↗
PubMed1986

Complete reactivation of X chromosomes from human chorionic villi with a switch to early DNA replication.

Mammalian sex-dosage compensation is mediated by maintaining activity of only one X chromosome. The asynchronous DNA synthesis characterizing the silent human X chromosome is thought to be reversible only during ontogeny of oocytes. We have previously shown that the glucose-6-phosphate dehydrogenase (G6PD) locus (G6PD) on the allocyclic X chromosome in chorionic villi is partially expressed. We now show that in hybrids derived from a clone of chorionic villi cells (heterozygous for G6PD A) and mouse A9 cells, the loci for G6PD, hypoxanthine phosphoribosyltransferase (HPRT) and phosphoglycerate kinase are expressed on both human X chromosomes; the human X chromosomes carrying either G6PD A or B replicate synchronously with each other and with murine chromosomes. The X chromosome with G6PD A was identified as the original late-replicating X, because methylation in the body of the HPRT gene on this chromosome remained characteristic of the inactive X chromosome. These results indicate that X-chromosome inactivation is completely reversible in cells of trophoblast origin; induction of full transcriptional activity is accompanied by acquisition of isocyclic replication, showing an intimate relationship between these processes. The molecular events responsible for this reversal may be similar to those occurring during maturation of oocytes. Chorionic villi and derivative hybrids provide in vitro models for exploring early events that program the single active X chromosome.

Animals↗
PubMed1986

Protection of the ischaemic myocardium by L-propionylcarnitine: effects on the recovery of cardiac output after ischaemia and reperfusion, carnitine transport, and fatty acid oxidation.

The effects of L-propionylcarnitine on the recovery of cardiac contractile performance after global ischaemia and reperfusion were studied in isolated perfused rat hearts. The addition of either 5.5 or 11 mmol X litre-1 L-propionylcarnitine significantly improved the recovery of cardiac output, left ventricular pressure, and dP/dt after 90 min of ischaemia and 15 min of reperfusion. Myocardial adenosine triphosphate and creatine phosphate concentrations were significantly higher in the L-propionylcarnitine treated hearts than in controls, but the concentrations of long chain acyl carnitine and coenzyme A were unaffected. The protecting effects of L-propionylcarnitine were compared with those of L-carnitine and L-acetylcarnitine. A 11 mmol X litre-1 dose of L-propionylcarnitine and L-acetylcarnitine significantly improved the recovery of cardiac output after 90 min of ischaemia and 15 min of reperfusion, but L-carnitine did not. L-Propionylcarnitine was the most protective agent. The effects of these derivatives on L-3H-carnitine transport and 14C-palmitate oxidation were also measured. All of these derivatives competitively inhibited L-3H-carnitine transport in isolated cardiac myocytes, but L-propionylcarnitine was the most potent. Carnitine and L-propionylcarnitine stimulated palmitate oxidation in the homogenate, whereas L-acetylcarnitine inhibited it. In myocytes only L-propionylcarnitine affected palmitate oxidation. These data show that L-propionylcarnitine protects the ischaemic myocardium. Its protection is greater than that for L-carnitine or L-acetylcarnitine, and the difference in effectiveness may relate to the rate of transport into the cells and the effects on fatty acid utilisation.

Acetylcarnitine↗
PubMed1986

Effect of angiotensin converting enzyme inhibitors on the vasoconstrictor action of angiotensin I on isolated rat kidney.

On the isolated perfused rat kidney, the angiotensin converting enzyme (ACE) activity was evaluated with two approaches: one, pharmacological, through the vasoconstrictor response to angiotensin I (ANG I), and the other, biochemical, through the measurements of the enzymatic activity on renal homogenate. ANG I and angiotensin II (ANG II) induced a concentration-dependent renal vasoconstriction (EC50 = 10.5 +/- 1.8 X 10(-9) and 1.1 +/- 0.5 X 10(-9) M, respectively). Both responses were competitively antagonized by an ANG II receptor antagonist, saralasin (pA2 = 8.65 +/- 0.63 and 8.94 +/- 0.28, respectively). The effects of ACE inhibitors were studied in vitro after addition of captopril and ramiprilat (10(-5) M) directly to the perfusion medium, and ex vivo, after pretreatment of the rats with ramipril (50 mg/kg, i.p. the day before or 10 mg/kg/day, per os, over 3 weeks). In spite of the high doses of ACE inhibitors used, the ANG I concentration-response curve was only shifted to the right by a factor of 4, although renal tissue ACE activity was completely inhibited. Saralasin (10(-5) M) totally abolished the ANG I-induced vasoconstriction elicited in the presence of ACE inhibitors, this response being therefore linked to a generation of ANG II from ANG I. Our results suggest that, on the isolated perfused rat kidney, ANG II may be formed from ANG I by a peptidyl dipeptidase different from the ACE.

Angiotensin I↗
PubMed1986

[Pain therapy in tumor patients].

The incidence of pain associated with advanced cancer is very high. In addition, most patients are also suffering from emotional and social problems. In the choice of pain treatment the different processes of nociception have to be considered. Thus non-narcotic analgesics and psychotropic agents may be combined to reduce opiate requirements. Oral medication is to be preferred and should be given on a strict schedule. Pain syndromes irresponsive to this pharmacological treatment are indications for neurosurgical procedures, epidural opiates and neurolytic nerve blocks.

Analgesics↗
PubMed1986

[Sermion].

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Adrenergic alpha-Antagonists↗
PubMed1986

[Effect of silver compounds on viruses in water].

Two commercial substances, Certisil and Micropur, containing microbicidal silver compounds and destinated for decontamination as well as preservation of water were examined for virus inactivating activity against ECBO-, influenza A, Newcastle Disease, pseudorabies and vaccinia viruses in drinking water. In the recommended concentration as well as higher concentrated the lability of the viruses was increased by the silver compounds. This activity which cannot be designated as a true virucidal effect was clearly evident in the case of ECBO and vaccinia viruses, moderate on influenza and pseudorabies viruses but insignificant on Newcastle disease virus. Two combined silver compounds, Certisil-Combina and Sanosil, each containing an immediate microbicidal part besides silver differed in their antiviral activity. The chlorine separating part of Certisil-Combina didn't cause an improvement or acceleration of the destabilizing effect on viruses compared to the pure silver compound, while the hydrogen peroxide part of Sanosil led to a better and continuing inactivating influence on the viruses which were merely reduced in infectivity by 99,9% within one day. Only in the case of evident or suspected contamination of water reservoirs by viruses the addition of a combined silver drug with oxygen separating part seems to be useful.

Antiviral Agents↗
PubMed1986

[Comparison of the vasomotor effects of dopamine on the renal and iliac arterial beds of the anesthetized rat].

Dopamine remains the reference in the study of the mechanisms involved in the antihypertensive effects of dopaminomimetics. Its renal vasodilator effects are well characterized but relaxation of other vascular beds is less known. The iliac vascular response to dopamine was studied in the anesthetized rat (pentobarbital) and compared to the renal response. Simultaneous measurements of arterial pressure, iliac and renal blood flows (electromagnetic flowmeter probes, Skalar, Delft) allowed iliac and renal vascular resistance (IVR, RVR) to be calculated. Their variations were studied after intravenous injections of increasing doses of dopamine (1.5 to 200 micrograms/kg) in unpretreated animals and in animals receiving various pretreatments. Without pretreatment, dopamine induced a biphasic renal response, vasodilation partially masked by subsequent vasoconstriction for doses above 12.5 micrograms/kg of dopamine. Simultaneously, IVR was increased. After alpha-adrenolytic pretreatment (prazosin 2.5 mg/kg, i.v.), dopamine decreased the RVR while iliac vasoconstriction persisted. The association of yohimbine (5 mg/kg, i.v.) to prazosin completely abolished the vasoconstrictive effects: dopamine lowered then by about 30% both IVR and RVR. Dopamine-induced iliac and renal decrease in vascular resistance persisted in the presence of a beta-adrenoceptor antagonist [+/-)-sotalol 30 mg/kg, i.v.), after depletion of catecholamines from sympathetic terminals (reserpine 10 mg/kg, i.p. 20 h before the experiment) or inhibition of cyclo-oxygenase (indomethacin 2.5 mg/kg, i.p. 20 h and 1 h before dopamine). On the contrary, a specific antagonist of dopamine receptors, (+)-butaclamol (60 micrograms/kg/min, i.v.) stereoselectivity inhibited the dopamine-induced renal vasodilation but did not modify the iliac response.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗