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Biomedical subjects

B Simon

Publications and source records attributed to B Simon.

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

Membrane SH-groups related to adrenaline action in rat adipocytes: a comparative study using sulfhydryl reagents of different molecular size.

The orientation of SH-groups within the fat cell membrane involved in adrenaline (and NaF) action was studied by comparing the effects of uncoupled p-CMB with those of a large derivative of this reagent -- p-CMB-dextran --. Preincubation of intact adipocytes with uncoupled p-CMB caused a dose-dependent inhibition of adrenaline (and NaF) stimulated adenylate cyclase activity as determined in ghosts prepared subsequently. Preincubation with p-CMB-dextran, however, influenced neither the lipolytic response to adrenaline nor the catecholamine (and NaF) activated adenylate cyclase activity. When p-CMB-dextran was present during ghost preparation, a dose-dependent inhibition of adrenaline (and NaF) stimulated adenylate cyclase activity was observed. These results suggest that the binding sites of adrenaline as well as SH-groups essential for activity of adenylate cyclase are not localized near enough to the exterior surface to be accessible for p-CMB-dextran. The polarity in the sensitivity of fat cell adenylate cyclase could not be observed when p-CMB-dextran was added directly to intact or fragmented ghosts. The abbreviations used are: Cyclic AMP, cyclic adenosine 3',5'-monophosphate; p-CMB, p-chloromercuribenzoate.

Adenylyl Cyclases↗
PubMed1976

Non-specific inhibition of membrane-ATPase by amiloride: a comparative in vivo and in vitro study with ouabain.

The submaxillary duct epithelium, which actively transports Na+ (rabbit) and, in addition, K+ and H+/HCO-/3 (rat), was used as a model epithelium to compare the effects of ouabain and amiloride on transport parameters. 1. Ouabain was only effective from the interstitial side, amiloride, however, only from the luminal side. Amiloride induced effects on transport of the ions were seen within less than 1 s, ouabain effects, however, only after minutes. 2. Ouabain inhibited in a parallel fashion the Na+ transport potential and the Na+-K+-ATPase activity. It had no effect on the Mg2+-ATPase and the HCO-/3-ATPase. 3. Amiloride also inhibited the Na+ transport potential and the Na+-K+-ATPase; however, the Na+ transport potential was significantly more sensitive to amiloride than the Na+-K+-ATPase. 4. Amiloride inhibited in a similar fashion the Na+-K+-ATPase, the Mg2+-ATPase and the HCO-/3-ATPase, but did not influence active HCO-/3 secretion. 5. It is concluded that the amiloride induced effects on the membrane ATPases are non-specific.

4-Nitrophenylphosphatase↗
PubMed1976

Catecholamine-sensitive adenylate cyclase of human fat cell ghosts. Characteristics of the GMP(PNP)-liganded state.

The effects of 5'-guanylyl-imidodiphosphate (GMP(PNP)) on the catecholamine-sensitive adenylate cyclase of human fat cell ghosts were studied. The compound increased basal and epinephrine-stimulated enzyme activity by about 300%; in addition GMP(PNP) increased hormone sensitivity by reducing the epinephrine concentration required, to produce half maximal stimulation. The rate of GMP(PNP)-induced activation was slow in onset and could be enhanced by epinephrine. The GMP(PNP)-activated state was resistant to thermal inactivation and could not be reversed by extensive washing. The application of this compound in clinical studies may be useful because of its stimulating and stabilizing action.

Adenylyl Cyclases↗
PubMed1975

[Panarteritis nodosa-Special aspects of glucocorticoid and immune suppressive therapy (author's transl)].

Report dealing with the clinical and pathoanatomical course as well as the autopsy findings in a 54 year old female suffering from panarteritis nodosa. Onset of the illness with polyneuritis and arthralgia. One year later diagnosis of panarteritis nodosa verified by muscle biopsy. Deterioration of the disease leading to the development of peripheral gangrene could not be prevented in spite of intensive therapy with steroids, immune suppressive agents, digitalis and antihypertensive drugs. Death 4 years later by myocardial infarction. Autopsy revealed generalized healed panarteritis nodosa with scarring and obliteration of vessels. A short description of the symptoms of the disease is given and the efficacy of the therapy with steroids and immune suppressive drugs is discussed from the clinical as well as the pathoanatomical point of view. Immunopathologic mechanisms are considered to be the responsible factors for pathogenesis.

Antihypertensive Agents↗
PubMed1975

Amplification of the bradykinin response in rat uterus by pCMB-Dextran T 10.

pCMB-Dextran T 10,a large, non-penetrating SH-blocking reagent caused a reversible amplification of bradykinin sensituvity in the isolated rat uterus. High concentrations of this compound (1 x 10-3 M) can evoke spontaneous uterus contraction. pCMB-Dextran T 10 did not alter the biological activity of bradykinin. It is assumed that superficial membrane SH-groups are involved in the uterus contraction mechanism.

Animals↗
PubMed1975

p-CMB-dextran T 10. A useful tool in evaluating the functional importance of superficial SH-groups in rat adipocytes.

A large SH-blocking reagent p-CMB-dextran T 10 (MW about 10,000) was applied to isolated rat adipocytes. This compound possesses the same reactivity towards SH-groups as uncoupled p-CMB. P-CMB-Dextran T 10 did not influence the basal glucose uptake in contrast to uncoupled p-CMB. The results are discussed with respect to the usefulness of p-CMB-dextran T 10 in evaluating the role of superficial SH-groups in various membrane functions.

Adipose Tissue↗
PubMed1975

Effects of SH-reagents of different molecular size upon glucose metabolism in isolated rat fat cells.

To study the role of membrane SH-groups in glucose transport of isolated rat fat cells we compared the effects of a small organic mercurial reagent p-CMB with those of a large p--CMB-derivative -- p-CMB-Dextran, MW 10.000 --. It could be shown that both compounds were of almost identical reactivity on fat cell homogenate metabolism. When applied to intact fat cells uncoupled p--CMB showed an (1) insulin like enhancement of 14C incorporation from (U-14C) glucose into CO2 and triglyceride, (2) inhibition of the insulin-stimulatory effect on these parameters and (3) inhibition of basal glucose uptake dependent on the concentrations used. Identical concentrations of p-CMB-Dextran, however, failed to influence basal glucose uptake as well as the insulin mediated increase in glucose metabolism.

Adipose Tissue↗
PubMed1975

[Fistulae in esophageal surgery. (Solidity of the esophageal wall and the role of infection)].

The strength of the eosophageal wall has been tested in 20 autopsy specimens: it proved to be as resistant as the stomach and the jejunum. It dépends as elsewhere in the digestive tract on the deep layer of the mucosa (Halstedt's submucosa): the success of an anastomosis depends on the passage of sutures through this submucosa. Vascularization does not seem to be a problem, provided certain precautions are taken. The necrotizing properties of saliva and infection especially in cancerous surgery might be the main causes of fistulas.

Esophageal Diseases↗
PubMed1975

[Giant-cell (Takayasu) arteritis as a cause of renovascular hypertension].

In a young female with renovascular hypertension multiple stenoses affecting both renal arteries, abdominal aorta and left axillary artery could be demonstrated. The elevated blood pressure could be normalized by bypass operation of the renal arteries. Histopathologic findings were those of giant cell (Takayasu) arteritis.

Adolescent↗