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Biomedical subjects

S Schmidt

Publications and source records attributed to S Schmidt.

At least 433 records · Page 24Linked to original sources
PubMed1987

[Congenital portosystemic shunt in dogs and cats].

An overview of the circulation of the liver and of the pathogenesis of hepatic encephalopathy as a result of portal vascular anomalies is given. Clinical signs associated with portal systemic shunts are described on the basis of 16 cases, 14 dogs and 2 cats. These animals ranged in age at the time of presentation from 4 months to 7 years. The predominant abnormality observed were central nervous signs, which differed in severity. The different techniques of contrast angiography allowing demonstration of a portal systemic shunt are presented along with a discussion of the pros and cons of each. Additionally the significance of making portal venous pressure measurements prior to each angiography is also explained. In most cases mesenteric portography was chosen. Based on their location the anomalies could be categorized as intrahepatic (4 dogs) or extrahepatic (10 dogs, 2 cats). In both groups breeds of various size are represented. The extrahepatic shunts could be further described as portal-caval (n = 5), portal-phrenic (n = 4) and portal-azygos (n = 3). In five of the older animals angiography showed in addition some hepatic perfusion by the portal vein. Laboratory evaluation revealed increased resting blood ammonia concentrations (greater than 200-912 micrograms/100 ml) in all animals. Seven dogs had definitely subnormal BUN concentrations (less than 10 mg%) and ten dogs low total plasma protein levels (less than 5.4 g%). Free amino acids (24) were determined in four dogs and a lowered hepatic encephalopathy index (less than 1.64) found. Medical palliative therapy to control the clinical signs is discussed. The only effective long term therapy is, however, surgery. The shunt vessel is narrowed so that a greater volume of portal blood reaches the liver. Experience gained from the surgical therapy of 14 animals is presented. Ten of these survived well without requiring further therapy at a later time. Finally the etiology, prognosis, and differential diagnosis are summarized.

Animals↗
PubMed1986

Determination of platelet-megakaryocyte regeneration time in painters occupationally exposed to organic solvents.

An improved method for the determination of the regeneration time of human platelets is presented. The platelet-megakaryocyte regeneration times of painters exposed to organic solvents (n = 5; age range 23-48 years) were compared with a reference group (n = 5; age range 23-46 years) not occupationally exposed to solvents. After purification and extraction of the samples, they were analysed by high-performance liquid chromatography. The results showed that the painters have a shorter regeneration time (range 4.4-5.2 days) than the reference group (range 5.2-6.9 days) and indicate that solvent exposure may be associated with an increase in platelet turnover in man.

Adult↗
PubMed1986

Bacterial beta-lyase mediated cleavage and mutagenicity of cysteine conjugates derived from the nephrocarcinogenic alkenes trichloroethylene, tetrachloroethylene and hexachlorobutadiene.

The metabolism of beta-lyase and the mutagenicity of the synthetic cysteine conjugates S-1,2-dichlorovinylcysteine (DCVC), S-1,2,2-trichlorovinylcysteine (TCVC), S-1,2,3,4,4-pentachlorobuta-1,3-dienylcysteine (PCBC) and S-3-chloropropenylcysteine (CPC) were investigated in Salmonella typhimurium strains TA100, TA2638 and TA98. The bacteria contained significantly higher concentrations of beta-lyase than mammalian subcellular fractions. Bacterial 100,000 X g supernatants cleaved benzthiazolylcysteine to equimolar amounts of mercaptobenzthiazole and pyruvate. DCVC, TCVC and PCBC produced a linear time-dependent increase in pyruvate formation when incubated with bacterial 100,000 X g supernatants; pyruvate formation was inhibited by the beta-lyase inhibitor aminooxyacetic acid (AOAA). CPC was not cleaved by bacterial enzymes to pyruvate. DCVC, TCVC and PCBC were mutagenic in three strains of S. typhimurium (TA100, TA2638 and TA98) in the Ames-test without addition of mammalian subcellular fractions; their mutagenicity was decreased by the addition of AOAA to the preincubation mixture. CPC was not mutagenic in any of the strains of bacteria tested. These results indicate that beta-lyase plays a key role in the metabolism and mutagenicity of haloalkenylcysteines when tested in S. typhimurium systems. The demonstrated formation in mammals of the mutagens DCVC, TCVC and PCBC during biotransformation of trichloroethylene (Tri), tetrachloroethylene (Tetra) and hexachlorobutadiene (HCBD) may provide a molecular explanation for the nephrocarcinogenicity of these compounds.

Animals↗
PubMed1986

The restriction endonuclease Alu I induces chromosomal aberrations in human peripheral lymphocytes in vitro.

The restriction endonuclease Alu I (recognition site AG/CT) produces chromosomal aberrations in isolated human peripheral lymphocytes in vitro. The aberrations are of the chromosome-type when the cells are treated in G1 and of the chromatid-type when the cells are treated in late S, early G2. Additional treatment with ammonium sulphate leads to higher aberration frequencies than treatment with Alu I alone.

Ammonium Sulfate↗
PubMed1986

Metabolism of ethanol in vitro produces a compound which induces sister-chromatid exchanges in human peripheral lymphocytes in vitro: acetaldehyde not ethanol is mutagenic.

Ethanol (EtOH) in the presence of the EtOH-metabolizing enzyme, alcohol dehydrogenase (ADH) leads to the induction of sister-chromatid exchanges (SCEs) in human peripheral lymphocytes in vitro. Acetaldehyde (AA) induces SCEs, whose frequencies are lowered in the presence of the AA-metabolizing enzyme, aldehyde dehydrogenase (ALDH). EtOH in the presence of ADH produces more SCEs than EtOH in the presence of ADH and ALDH. These data are interpreted to show that not ethanol itself, but its first metabolite acetaldehyde is mutagenic.

Acetaldehyde↗
PubMed1986

Clinical linguistic and auditory milestone scale: prediction of cognition in infancy.

At each well-child examination between birth and two years, parents of 448 infants were questioned about their child's age at attainment of 25 linguistic and auditory milestones. Parental reports were compared with the results of independently administered Bayley Mental Developmental Index (MDI) at one year of age. Parental recall of information was high, ranging from 70 to 99 per cent for 21 of the 25 milestones. The milestone performance of infants with normal MDI scores showed an orderly, sequential progression of expressive and receptive language. Across the entire population studied, the correlation between milestone attainment and MDI was statistically significant for 24 of the 25 milestones, and later attainment of milestones correlated with lower MDI. As a group, 'delayed' infants (MDI less than 68) attained milestones significantly later than 'average' infants (MDI 85 to 116) for 20 of 25 items. Attention to linguistic and auditory milestones early in infancy can contribute to the early detection and diagnosis of mental retardation and disorders of communication.

Auditory Perception↗
PubMed1986

[Ultrasonic diagnosis in gynecology in small animals].

After a short introduction into the basics and the different methods of sonography a description of the ultrasonographic diagnosis of gynaecological diseases in small animals is given. The ultrasonographic method is indicated in all gynaecological diseases after the anamnesis, clinical and laboratory work up and before x-rays and invasive methods will be used. The sonographic characteristics for interpretation are described. Typical sonographic findings are demonstrated in 16 cases as in diseases of the cervix (inflammation, cyst), uterus (pregnancy, endometritis - pyometra), ovaries (cysts), and mamma (lactation, abscesses, tumors).

Animals↗
PubMed1985

Development of a prosthetic venous valve.

The pathology of thrombophlebitis primarily results from the obliteration of venous valves in the lower extremities. The objective of this study was to develop a prosthetic venous valve that could be implanted in the human femoral system to ameliorate the deleterious effects of thrombophlebitis. Prosthetic venous valves were produced from two materials: Pellethane valves were fabricated from a dip-casting process; umbilical vein valves were produced by a fixation process. The valves were evaluated as implants within the external jugular veins of 10 research dogs. Each animal was implanted with one Pellethane valve in one external jugular vein and one umbilical vein venous valve in the contralateral jugular vein. Each valve was positioned over a stainless-steel cylinder that had been implanted into the jugular veins in such a manner that there existed no blood-cylinder interaction. Patency of the valves was determined by X-ray venography at 24, 48, and 72 h and at 5 and 8 days postoperatively. All of the umbilical vein venous valves were occluded by the end of 48 h, whereas two of the Pellethane venous valves remained patent for at least 5 days but were occluded at 8 days. The results of this study suggest the possibility of success of Pellethane valve implants in the venous circulation and indicate future directions for study.

Animals↗
PubMed1985

Measurement of transcutaneous pCO2 and pO2 in the fetus during labor.

We used newly developed transcutaneous electrodes to measure continuously the partial pressure of oxygen (tcpO2) and carbon dioxide (tcpCO2) in 34 fetuses during labor, having simultaneous cardiotocography (CTG) and temperature measurements. We observed that tcpO2 and tcpCO2 varied with contractions during the first and second stages of labor. In some cases changes in the transcutaneous values corresponded well with changes in the CTG, we also detected changes in the fetal gas metabolism that were not noticeable on the cardiotocographic tracing. We defined the characteristic of the tcpO2 and tcpCO2 during the second stage of labor and found that the tcpO2 decreased and the tcpCO2 rose at this time.

Carbon Dioxide↗
PubMed1985

Dietary effects on (pro)insulin biosynthesis and insulin-degrading activity in islets from sand rats.

Sand rats were fed either a vegetable (vegetable group) or a standard pellet diet. After 14-16 weeks, the normoglycemic subgroup selected (pellet group) from the animals that had been maintained on the standard diet showed a modest increase in body weight. Plasma immunoreactive insulin levels were not significantly increased, but glucose-stimulated insulin release was elevated from islets isolated from sand rats of the pellet group. Insulin biosynthesis was estimated in vitro by measuring [3H]leucine incorporation into (pro)insulin at 1.5 or 15 mmol/l glucose. The rate of (pro)insulin biosynthesis was elevated only at 15 mmol/l glucose in islets from those normoglycemic sand rats fed the pellet diet when compared with islets from the vegetable group. Specific insulin-degrading activity, as determined by measuring degradation of 125I-labeled insulin, was also increased for islets from the pellet group. The metabolic state of these sand rats is thus associated with normoglycemia in vivo, and increased stimulated rates of insulin biosynthesis and degradation in pancreatic islets in vitro.

Animals↗