Search PubMed⌕ Search

Biomedical subjects

G Koch

Publications and source records attributed to G Koch.

At least 469 records · Page 26Linked to original sources
PubMed1976

Control of peptide chain initiation in uninfected and virus infected cells by membrane mediated events.

Initiation of protein synthesis in tissue culture cells is rapidly inhibited or blocked by addition of either DMSO, ethanol, TPCK, cytochalasin B, or sucrose to the growth medium. In contrast, these agents do not interfere with the initiation of protein synthesis in cell-free extracts to a comparable extent. These results support the hypothesis that protein synthesis in tissue culture cells can be influenced by membrane mediated events. Translation of viral mRNA in RNA virus infected cells is resistant to a number of these inhibitors of peptide chain initiation and proceeds under conditions where translation of host mRNA is almost completely suppressed. It appears that viral mRNA possesses a greater ability than host mRNA to form mRNA-ribosome initiation complexes when the overall rate of peptide chain initiation is reduced. This observation has led to a number of predictions concerning the strategy of virus directed suppression of host mRNA translation. Under optimal growth conditions protein synthesis appears to be regulated mainly, but not exclusively, by the amount of the mRNA available for translation. However, when cellular growth and/or the overall rate of peptide chain initiation is restricted, control of protein synthesis at the translational level becomes decisive with the translation of each mRNA species proceeding with its own characteristic efficiency most probably as a result of inherent differential affinities of individual mRNA species for ribosomes.

Cell Line↗
PubMed1976

Individual translational efficiencies of SV40 and cellular mRNAs.

The technique of selective inhibition of peptide chain initiation by growth medium hypertonicity was adapted for cell monolayer cultures and applied to a study of protein synthesis in SV40 infected BSC-1 cells. The translational efficiences for individual peptide chain initiation sites on SV40 mRNAs were determined and compared to those for cellular mRNA species under conditions of a reduced rate of peptide chain initiation. The SV40 mRNAs show different translational efficiences. The results indicate that the synthesis of the SV40 proteins VP1, 2 and 3 are initiated independently and with different rates on viral mRNA(s). It is proposed, therefore, that VP2 is not a precursor for VP3.

Cell Line↗
PubMed1976

Inhibition of protein synthesis in reticulocyte lysates by poliovirus.

Addition of 1 X 10(10) p.f.u. purified poliovirus to 100 mul of a rabbit reticulocyte lysate protein synthesizing system causes a complete inhibition of initiation of protein synthesis. This inhibition is not due to the viral RNA nor to any contaminants of the preparation, but is most likely caused by the viral coat protein.

Animals↗
PubMed1976

On the regulation of protein synthesis in vaccinia virus infected cells.

All eukaryotic mRNA species show a characteristic individual translational efficiency under conditions of restricted polypeptide chain initiation caused by an increase in the osmolarity of the growth medium. In vaccinia virus infected L cells or HeLa cells virus mRNAs can be grouped into classes on the basis of their relative labelling under standard and hypertonic conditions. Under the latter conditions, most of the "early" mRNAs possess very high translational efficiencies, most of the "intermediate" mRNAs show an intermediate efficiency and the most prominent "late" mRNAs show a translational efficiency which is lower than that of other virus mRNAs but still higher than the average cellular mRNA. Late in the infection cycle virus mRNAs with a relative low translational efficiency are preferentially translated under standard growth conditions whereas "early" virus mRNAs which are still present and which show a higher translational resistance to hypertonic conditions are not translated. These results indicate a unique translational control operating late in the growth cycle of vaccinia virus.

HeLa Cells↗
PubMed1976

Translation of individual host mRNA's in MPC-11 cells is differentially suppressed after infection by vesicular stomatitis virus.

Infection of MPC-11 mouse plasmacytoma cells by vesicular stomatitis virus results in 30 to 35% reduction in [35S]methionine incorporation into total proteins within 30 min postinfection. By 6 h postinfection, total protein synthesis is reduced by 80 to 90%. However, even by 30 min postinfection, a differential suppression of the synthesis of individual host protein is observed. The synthesis of the immunoglobin G (IgG) heavy chain (H), and, in particular, the synthesis of IgG light chain (L), is considerably more resistant to vesicular stomatitis virus-induced inhibition than is the synthesis of the non-IgG proteins as a whole; e.g., when the synthesis of non-IgG proteins was reduced by 41%, the synthesis of the H and L chains was reduced by 28 and 7%, respectively. Furthermore, these alterations in the relative synthesis of the L chain, H chain, and non-IgG are comparable to the alterations previously observed in uninfected MPC-11 cells when the overall rate of polypeptide chain initiation was selectively reduced (D.L. Nuss and G. Koch, 1976). These results are discussed in terms of the strategy of virus-directed suppression of host mRNA translation.

Animals↗
PubMed1976

Haemodynamic adaptation at rest and during exercise to long-term antihypertensive treatment with combination of beta-receptor blocking and vasodilator agent.

Systemic and pulmonary haemodynamics were studied at rest in the supine and upright position, and during exercise in the sitting position at 75 and 150 Watt, in 13 hypertensive men aged 50-8 +/- 8-7 years before and after 13 months treatment with oral oxprenolol (120 to 160 mg t.i.d.) supplemented by oral hydrallazine (50 to 75 mg t.i.d.) during the last 6 months. Pressures were recorded by means of catheters inserted percutaneously into the pulmonary and brachial artery; cardiac output was determined according to Fick. Treatment resulted in a significant reduction of systemic systolic, diastolic, and mean pressures at rest in the supine position and during exercise, and of systolic pressures in the upright posture. Pulmonary systolic and mean pressures increased slightly at rest in the supine position and during exercise, and no changes occurred at rest in the upright position. The left ventricular filling pressure was unchanged at rest both in the supine and upright position; it increased slightly during exercise. The haemodynamic changes by which systemic pressure was reduced were those typical of beta-adrenergic blockade: reduction of cardiac output resulting from a decrease of both heart rate and stroke volume, while the total systemic vascular resistance was unchanged at rest in the supine position but increased in the upright posture and during exercise. The A-V O2 difference increased remarkably. This long-term observation again suggests that the acute haemodynamic effects of an antihypertensive regimen can be modified during long-term application. It did not give evidence of a readjustment of the vascular resistance occurring, at least not in the upright position and during exercise, as has been suggested for long-term beta-adrenergic blockade.

Adult↗
PubMed1976

Haemodynamic effects of combined alpha- and beta-adrenoreceptor blockade after intravenous labetalol in hypertensive patients at rest and during exercise.

1 The haemodynamic effects of labetalol 50 mg intravenously were studied in 13 hypertensive patients at rest in the supine and upright positions and during exercise using percutaneous right heart and brachial artery catheterization. 2 Labetalol induced immediate significant reductions in systolic and diastolic blood pressures in all conditions. 3 Heart rate, stroke volume and cardiac output were not significantly altered in the supine position at rest but were significantly reduced in the upright position. In addition systemic vascular resistance was significantly reduced. 4 During exercise, heart-rate, cardiac output and vascular resistance were significantly reduced; stroke volume was increased. Left ventriclac filling pressures were unchanged both at rest and during exercise. 5 It was concluded that these changes resulted from blockade to both alpha- and beta-adrenoreceptor.

Adrenergic alpha-Antagonists↗
PubMed1976

Combined alpha- and beta-adrenoreceptors blockade with oral labetalol in hypertensive patients with reference to haemodynamic effects at rest and during exercise.

Twelve hypertensive patients received oral labetalol treatment (average final dose 1,200 mg/d) over a period of 16 months. 2 Satisfactory blood pressure control was maintained both at rest and after exercise. 3 Plasma renin activity was significantly reduced. 4 Postural hypotension measured in this group of patients after a single dose of labetalol 50 mg intravenously was considerably reduced during long-term oral treatment. 5 No serious side-effects were observed nor were there any significant changes in haematological and biochemical variables during the period. 6 Haemodynamic data obtained in two of the patients after 16 months' treatment suggests that the haemodynamic profile observed after acute intravenous administration is maintained after prolonged oral treatment.

Administration, Oral↗
PubMed1976

Effect of fominoben-HCl on circulation, pulmonary gas exchange and acid-base balance at rest and during exercise.

The effect of 3'-chloro-2'-[N-methyl-N[(morpholino-carbonyl)methyl]aminomethyl]benzanilide-hydrochloride (forminoben-HCl, Noleptan) on pulse rates and blood pressures, ventilation and gas exchange, and acid base balance was studied in eleven patients aged 31 to 72 years at rest and during a standardised excercise. Mean systolic and diastolic blood pressures decreased at rest before and 10 min after work as well as during work. Mean alveolar ventilation was reduced by 9% at rest and was unchanged during work. No changes occurred in mean alveolar-arterial oxygen differences or in mean anatomical right-to-left shunt. In a few individual patients with grossly impaired intrapulmonary gas exchange, however, an improvement with regard to alveolar ventilation in relation to oxygen uptake and the alveolar-arterial oxygen tension difference could be demonstrated.

Acid-Base Equilibrium↗
PubMed1976

[Enzyme histochemistry of the sand rat pancreas (Psammomys obesus) after different caloric food].

In a complex investigation were evidenced 12 selected enzymes (oxidoreductases and hydrolases) in the pancreas of normoglycemic sand rats (Psammomys obesus). The sand rat developed a spontaneous diabetic metabolism by holding in the vivarium. The material based of animal groups that were fooded ad libitum or after defined dietetic regimes. The topochemical pattern of enzymes in the Langerhans' islets and exocrine acini can be compared between the sand rat groups and with the good investigated model of the Wistar rat. Because enzymhistochemical investigations of the sand rat pancreas absented, were the results compared with the rare specific observations of other animals and the man and the changed metabolic level were discussed under the especially food situation and in diabetes mellitus.

Acid Phosphatase↗
PubMed1976

[Immunhistochemical investigations for evidence of insulin, glucagon and gastrin in the islets of Langerhans of Wistar rats during the development (author's transl)].

Insulin, glucagon and gastrin were investigated immunohistochemically in the islets of Langerhans in 14, 15, 17, 18 and 20 days old embryos, in newborn, 2, 5, 10, 20 and 30 days old and adult Wistar rats. The results were documented in series of microphotos. By means of the indirected immunofluorescence technique the insulin and glucagon were observed from the 18th day of the prenatal development in the B- resp. A-cells of the islets. Than the intensity of the fluorescence shows a continual increase during the development. In the islets cells of the developing stages and adult rats can't immunohistochemically evidenced the gastrin. The important results were discussed from the standpoint of the development physiology.

Animals↗
PubMed1976

[Transplantation of isolated islets of Langerhans into the liver of diabetic dogs (author's transl)].

Isolated islets of Langerhans were transplanted through the portal vein in the liver of 8 diabetic dogs; In 4 dogs a homologous transplantation was performed and another group of four dogs received isolated islets from their sisters or brothers. In both groups, there was an immediate effect on the blood glucose level. After pancreatectomy and injection of Alloxan the blood glucose rose to between 350 and 420 mg per 100 ml and after islet implantation the blood glucose decreased between 80 to 160 mg per 100 ml. The iv GTT'S were after islet implantation clear better than in the diabetic control animals. These results could maintained in the recipients with homologues islets over a period of 6 to 8 weeks and in the other group of dogs over a period of 6 to 12 months. We were able to show, that the islet implantation in the liver of diabetic dogs did not disturb the microscopic architecture of the liver. No signs of portal hypertension, hepatic congestion and embolism were found.

Animals↗
PubMed1976

Radical hysterectomy with or without preoperative radium for stage IB squamous cell carcinoma of the cervix.

A retrospective study of 119 patients ranging from 30 to 69 years of age was undertaken to evaluate the effectiveness of preoperative radium treatment for patients with Stage IB (FIGO 1971) squamous cell carcinoma of the cervix undergoing radical hysterectomy. Results in 61 patients who had radical hysterectomy without preoperative radium treatment were compared to those in 58 patients who had received radium preoperatively. The patients receiving radium systems had an uncorrected 5-year survival rate of 89.7%, while the patients without preoperative radium treatment had a 75.1% 5-year rate of survival. This difference in survival rate was judged to be secondary to the greater incidence of lymphatic invasion and residual tumor in the surgical specimens of the patients who did not receive preoperative radium. The occurrence of significant gastrointestinal and urinary tract complications was identical in the 2 groups.

Adult↗
PubMed1976

[Primary retroperitoneal tumors. Symptoms-diagnosis--therapy].

Symptoms, diagnosis, and therapy of primary retroperitoneal tumors are presented with reference to 50 of the authors' cases. Seventy to 80% of the tumors are malignant; the most frequent are sarcomas. Males and females are equally afflicted; most cases are found within the 50-60 yearage range. First symptom is generally the palpable abdominal tumor. The diagnostic procedure of choic ist i.v. urography as well as selective angiograpms. At the time of diagnosis only 30-40% of tumors can be resected. Postoperative mortality ist about 10%. Seventy percent of tumors are radiosensitive. Prognosis can be considerably improved by postoperative radiation. Survival times of more than 2 years in patients presenting with malignant primary retroperitoneal tumors are exceptional.

Adolescent↗
PubMed1975

[Contribution to information and genetic counseling in Mekkel's syndrome (author's transl)].

The deformity syndrome nowadays named after Meckel is characterized by the following principal features: occipital encephalocele, cystic kidneys and a polydactyly. According to the available findings in twins and families, an autosomal recessive lethal syndrome is involved. In 8 (= 16.6%) of 48 families, the parents of the feature carrier were blood relations. Heterozygous anlage carriers cannot yet be recognized as such. To make a statement in genetic counselling today, ultrasonic diagnosis and an amniocentesis must be carried out early in a pregnancy at risk.

Abnormalities, Multiple↗