PubMed Health⌕ Search

Biomedical subjects

R Bock

Publications and source records attributed to R Bock.

At least 73 records · Page 4Linked to original sources
PubMed1991

Segmental renal hypoplasia of vascular origin causing renal hypertension in a 3-year-old girl.

A rare case of renal hypertension in a 3-year-old girl caused by segmental renal hypoplasia of vascular origin is presented. Resection of the hypoplastic segment of the kidney permitted successful treatment of the high blood pressure with preservation of renal function. Elevated plasma renin activity in the renal vein of the affected side and biochemical investigations demonstrated that the resected segment of the renal cortex was the source of the renin leading to hypertension by activation of the renin-angiotensin-aldosterone system.

Child, Preschool↗
PubMed1990

Renin-producing renal cell carcinoma.

The pathogenetic relationship between tumor and hypertension was investigated in 40 patients with renal cell carcinoma. 15 of 40 patients were hypertensive. Four of these 15 patients with renal tumors and hypertension (26.7%) were found to have primary reninism. In these patients the plasma renin activity in blood from the renal veins showed a tumor kidney to contralateral kidney ratio of between 6 and 7. In the same 4 cases the renin content in the renal tumor tissue was significantly higher than that in tissue from the adjacent tumor-free renal cortex of the ipsilateral kidney. Immunocytochemical demonstration of renin in the tumor was only possible in these 4 cases. In 3 of these patients blood pressure returned to normal following nephrectomy; in the 4th case there was a drop in blood pressure after nephrectomy. Renin-producing renal cell carcinomas are an uncommon cause of renal hypertension. The differential diagnosis of hypertension should therefore also include renal tumor.

Carcinoma, Renal Cell↗
PubMed1988

Comparison of 16S rRNA sequences from the family Pasteurellaceae: phylogenetic relatedness by cluster analysis.

The taxonomy of the family Pasteurellaceae has remained controversial despite investigations of biochemistry, serology, and nucleic acid relatedness. In an attempt to resolve some of this confusion, we have partially sequenced the 16S rRNAs of seven members of the family, representing all three genera. The sequences were aligned, similarity scores calculated, and single, average and complete linkage cluster analysis of the resulting distance matrix performed. In this way, an evolutionary branching pattern of these closely related species was reconstructed, and the approximate phylogenetic position of the family determined. Actinobacillus (Haemophilus) actinomycetemcomitans clustered with Haemophilus instead of Actinobacillus, supporting transfer of this species to the genus Haemophilus. Thus cluster analysis of phylogenetic relatedness was found to be particularly useful for studying closely related organisms, and could be performed using a microcomputer.

Actinobacillus↗
PubMed1986

Morphological changes of rat neurosecretory neurones after stereotaxic injection of kainic acid into the supraoptic nucleus or the supraoptico-hypophyseal tract.

Kainic acid is a structural analogue of glutamic acid possessing neurotoxic property. In the present study, performed on rats, morphological changes of neurosecretory neurones after stereotaxic injection of kainic acid into the left supraoptic nucleus or into the left supraoptico-hypophyseal tract were investigated. It is shown that administration of kainic acid in a dose that leads to destruction of hippocampal pyramidal cells has no effects on supraoptic perikarya but does destroy neurosecretory axons. These results contradict the observations of many authors who reported that local injection of kainic acid into the brain causes degeneration of perikarya but leaves axons of passage unaffected.

Animals↗
PubMed1986

Effect of salt loading and salt deprivation on the vasopressin and oxytocin content of the median eminence and the neural lobe in adrenalectomized rats.

In adrenalectomized rats the influence of salt loading or salt deprivation on the vasopressin and oxytocin content of the median eminence (ME) and the neural lobe (NL) was studied by means of various methods: morphometric and microphotometric analysis of aldehyde fuchsin-stained sections of ME and NL; immunohistochemical demonstration of neurophysin, oxytocin, and vasopressin in the ME and in the NL; radioimmunological measurement of oxytocin and vasopressin in the ME and in the NL. Adrenalectomy in salt-substituted rats raised the vasopressin content of the outer layer of the ME (OLME) but had no influence on the amount of vasopressin in the inner layer of the ME and in the NL. Osmotic stimulation of adrenalectomized rats by hypertonic saline markedly diminished vasopressin and oxytocin in the inner layer of the ME and in the NL but did not, or only slightly reduced vasopressin in the OLME. Withdrawal of salt supplementation in adrenalectomized rats resulted in a decrease of plasma sodium and plasma volume. It did not change the vasopressin or oxytocin content of the inner layer of the ME and of the NL, but it was correlated with a decrease of vasopressin in the OLME. The present findings may suggest that vasopressin in the OLME is involved in salt and/or volume regulation by influencing the hypophysial-adrenal axis.

Adrenalectomy↗
PubMed1985

Apramycin: minimal inhibitory concentrations for avian Escherichia coli and serum levels after intramuscular injection in turkeys.

The minimal inhibitory concentrations (MIC) of apramycin, a unique aminocyclitol antibiotic, for 100 Escherichia coli isolates recovered from clinical cases of avian colibacillosis were determined using the agar dilution method. All isolates were inhibited at apramycin concentration of 8.0 micrograms/ml; 90 and 50% of the isolates were inhibited at 6.6 and 3.4 micrograms/ml, respectively. A commercial injectable product containing 200 mg apramycin/ml was administered intramuscularly (i.m.) to groups of 6- and 12-week-old turkeys at 10, 15 and 20 mg/kg. Apramycin was quickly absorbed from the i.m. injection site. Mean peak serum drug concentrations were reached 1 h after treatment and were 19.5, 27.5 and 36.0 micrograms/ml, respectively. The serum elimination half-life (t 1/2) of the drug ranged between 1.75 h for the 10 mg/kg dose and 2.5 h for the 20 mg/kg dose. Very low concentrations of the drug were found 24 h after treatment. Duration of serum apramycin concentrations in relation to the MIC, dose, and age of birds was determined.

Age Factors↗
PubMed1983

Effect of adrenalectomy and administration of hypertonic saline on the content of aldehyde fuchsin-positive neurosecretory material and posterior lobe hormones in the median eminence and the neural lobe of rats.

The influence of adrenalectomy and administration of hypertonic saline on the amount of vasopressin, oxytocin, and neurophysin contained in the median eminence and the neural lobe of rats was studied by means of the following methods: (i) morphometric and microphotometric analyses of aldehyde fuchsin-stained histological sections of the neurohypophysis; (ii) immunohistochemical demonstration of vasopressin, oxytocin, and neurophysin in the neurohypophysis, and (iii) radioimmunological measurement of vasopressin and oxytocin in extracts of the median eminence and the neural lobe. Adrenalectomy increases the amount of vasopressin and neurophysin in the external layer of the median eminence but does not change the content of oxytocin. It has no influence on the amount of vasopressin, oxytocin, and neurophysin demonstrable in the inner layer of the median eminence and in the neural lobe two weeks after the operation. Hypertonic saline markedly diminishes the vasopressin, oxytocin, and neurophysin content of the inner layer of the median eminence and the neural lobe but reduces only slightly, if at all, the amount of vasopressin and neurophysin in the outer layer of the median eminence. The findings support the concept that osmotic stress reduces only the vasopressin and oxytocin content of the hypothalamus-neural lobe system and has no or only little influence on the vasopressin content of the outer layer of the median eminence.

Adrenalectomy↗