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Biomedical subjects

S Sen

Publications and source records attributed to S Sen.

At least 451 records · Page 25Linked to original sources
PubMed1983

[Acute and long-term effects of gallopamil (D 600) in stable angina pectoris--a randomized double-blind study].

The effects of the calcium-channel-blocking agent Gallopamil (D 600) were assessed in 20 patients with stable exertional angina pectoris in a randomized placebo-controlled double-blind protocol using serial exercise tests. Both after a single oral dose and during long-term treatment over 3 weeks, Gallopamil caused a dose-dependent increase in exercise duration and a reduction in ischemic ST segment depression that became clinically relevant using single doses of 50 mg. Since the rate-pressure product was not significantly affected by Gallopamil, its anti-anginal action cannot adequately be explained by a reduction in myocardial oxygen consumption as a result of this mechanism. The only side effects observed were asymptomatic second-degree sinoatrial block in one and first-degree atrioventricular block in another patient, each on 150 mg gallopamil daily. It thus seems justifiable to study the effectiveness of higher doses.

Adult↗
PubMed1983

[Incidence and significance of angina pectoris in aortic valve disease].

To determine the incidence and significance of angina pectoris in aortic valve disease, clinical, haemodynamic, and angiographic data concerning 111 consecutive patients aged 27-68 years (mean 52) were retrospectively analysed. 14.4% (group A) had significant, 85.6% (group B) had no coronary heart disease. There was a significant difference between the groups regarding the incidence of typical angina pectoris (62.5% vs 31.6%, p less than 0.01) and freedom from chest pain (12.5% vs 32.6%, p less than 0.05). No difference, however, could be found concerning the incidence of atypical chest pain (25% vs 35.8%). Of 12 patients aged over 50 years with coronary artery disease, no patient was free of angina pectoris. 83% had typical, 17% had atypical angina pectoris. Of 4 patients below 45 years with coronary artery disease, however, none had typical angina pectoris, 2 patients had atypical angina, and 2 patients had none. These results demonstrate that typical angina pectoris in patients with aortic valve disease is not a specific indicator of concomitant significant coronary artery disease. On the other hand, absence of chest pain does not predict absence of coronary artery disease, especially in younger patients. We therefore suggest that coronary angiography be carried out in all adult patients in whom aortic valve surgery is being considered.

Adult↗
PubMed1982

Asynchronous replication of constitutive heterochromatin on X chromosomes in female Mus dunni. Possible influence of facultative heterochromatin on the adjacent constitutive heterochromatin.

Euchromatin DNA of one X chromosome in mammalian females, which becomes facultatively heterochromatinized, is known to replicate asynchronously late in S phase compared to its active homologue. In the females of a pygmy mouse species Mus dunni, which has prominent segment of constitutive heterochromatin as the short arm of its submetacentric X chromosome, we have observed asynchronous replication of c-heterochromatin arm as well, predominant number of cells showing the segment associated with the facultatively heterochromatic X to be terminating later. The preferential later termination of replication of the c-heterochromatic arm on the "lyonized X" appears to be due to the influence of facultative heterochromatin on the adjacent constitutive heterochromatin.

Animals↗
PubMed1982

[Effects of oxyfedrine on sinus nodal function and AV-conduction (author's transl)].

In 20 patients the electrophysiologic effects of oxyfedrine at doses of 0.3 mg/kg/hr and 0.6 mg/kg/hr were studied. At the low dose, oxyfedrine caused a significant shortening of the absolute and rate-corrected sinus node recovery time by 16 and 27 percent, respectively. Sinus cycle length decreased slightly by 9 percent. Estimated sinoatrial conduction time tended to shorten, but not significantly so. AV-nodal conduction was slightly accelerated at sinus rhythm as well as during atrial stimulation; correspondingly paced cycle length at which Wenckebach AH-conduction occurred decreased. HV-interval remained unchanged. Increasing the dose of oxyfedrine had no additional effect on electrophysiologic parameters compared to the first dose used. The results demonstrate a moderate stimulatory action of oxyfedrine on sinus nodal automaticity and a slight acceleration of AV-nodal conduction. Whether the drug might be useful in the clinical setting for medical management of sinus nodal dysfunction or AV-conduction disturbances, remains to be elucidated on long-term studies; more pronounced effects of oxyfedrine than found in this investigation, however, are expected to be limited by its autoinhibitory action at higher dose levels.

Adult↗
PubMed1982

Application of proton-induced X-ray emission technique to gunshot residue analyses.

The proton-induced X-ray emission (PIXE) technique was applied to the identification and analysis of gunshot residues. Studies were made of the type of bullet and bullet hole identification, firearm discharge element profiles, the effect of various target backings, and hand swabbings. The discussion of the results reviews the sensitivity of the PIXE technique, its nondestructive nature, and its role in determining the distance from the gun to the victim and identifying the type of bullet used and whether a wound was made by a bullet or not. The high sensitivity of the PIXE technique, which is able to analyze samples as small as 0.1 to 1 ng, and its usefulness for detecting a variety of elements should make it particularly useful in firearms residue investigations.

Forensic Medicine↗
PubMed1981

Reversal of cardiac hypertrophy in renal hypertensive rats: medical vs. surgical therapy.

Cardiac hypertrophy consequent to renovascular hypertension was investigated in two-kidney one-clip Goldblatt rats. Ventricular weight in renal hypertensive rats correlated closely with level of arterial pressure (r = 0.93, P less than 0.001). DNA, RNA and hydroxyproline contents of the hypertrophied hearts were higher than sham control, but there was no significant change in myocardial concentration of any of them. Surgical treatment (removal of clipped kidney) as well as medical therapy (inhibition of converting enzyme with orally administered captopril, 150 mg/l drinking water) led to reduction of ventricular weight (2.70 +/- 0.01 and 2.78 +/- 0.06, respectively, vs. 3.4 +/- 0.05 mg/g in controls, P less than 0.01 for both). Reduction of cardiac weight was associated with increase in both myocardial concentration and content of hydroxyproline in surgically treated rats and in medically treated animals. Ventricular catecholamine concentration was increased after nephrectomy but was unchanged by captopril treatment.

Animals↗
PubMed1980

Quantitative variation of "Mus musculus-like" constitutive heterochromatin and satellite DNA-sequences in the genus Mus.

The extent of conservation of constitutive heterochromatin in three species of Mus viz. M. musculus, M. booduga and M. dunni, with shared cytological properties and homologous DNA sequences has been studied. The cytological properties were investigated by doing fluorescence staining and condensation inhibition of their chromosomes with Hoechst 33258. Both the parameters indicate the occurrence of a reduced quantum of "M. musculus like heterochromatin" at specific sites in the other two genomes. In situ hybridization of the nick translated 3H-labelled M. musculus satellite DNA with M. booduga and M. dunni chromosomes, also corroborates our Hoechst 33258 findings and comparable variation in the amount and site of occurrence of sequences homologous to M. musculus satellite DNA in these species are noticed. The study thus provides a good example of a gradual quantitative variation of a particular type of heterochromatin and in turn of the repetitive DNA constituting it in different related species. Further since the heterochromatin in M. booduga and M. dunni is expected to contain different repetitive DNA sequences in addition to those homologous to M. musculus satellite DNA, it is proposed that a change in the balance between two or more repetitive sequences in heterochromatin may be more crucial in its evolutionary consequences rather than a mere increase or decrease of a homogeneous repetitive sequence.

Animals↗
PubMed1980

In vitro steroidogenic properties of a new hypertension-producing compound isolated from normal human urine.

The steroidogenic properties of a glycoprotein fraction (ASF), isolated from normal human urine, were studied in cat adrenal capsular collagenase-dispersed cells and its effects compared to those of ACTH and Angiotensin II (AII). ACTH, AII and ASF induced dose-related increases in both aldosterone and cortisol production. In order of potency, ACTH = AII greater than ASF in stimulating aldosterone production and ACTH greater than AII greater than ASF in stimulating cortisol production. Increases in cAMP accompanied the steroidogenic response to ACTH but not to AII or ASF. The response to AII, but not to ASF, was inhibited (87% of normal) by equimolar concentrations of [Sar1, Thr8]AII, a specific AII antagonist. These results suggest that ASF is a true aldosterone secretagogue and that it initiates steroidogenesis by mechanisms similar to those of AII. However, the inability to block it effect with a specific antagonist of AII provides evidence for its action on a separate receptor site.

Adrenal Glands↗
PubMed1980

Skin test for gluten-sensitive enteropathy using subfractions of gluten.

Fractions and subfractions of gluten were used for intradermal testing in 14 patients with GSE and in 22 control subjects. Twelve out of 14 GSE patients gave positive skin reactions to one or more of the subfractions of gluten. Ten gave a positive reaction between three to eight hours after skin testing; two gave positive tests 20 minutes after injection. Only two out of the 14 had negative skin tests at all times tested. All 22 control subjects were negative to all the subfractions at all times tested. The control subjects consisted of 15 patients with GI disorders other than GSE, three patients with skin disorders other than dermatitis herpetiformis and four healthy controls. Of the three subfractions tested, subfraction B1 appeared most potent in evoking positive skin reactions as judged by the number of GSE patients who responded (11 of 14). Thus, skin testing individuals with this particular portion of gluten subfraction BA may prove to be a useful diagnostic test for GSE.

Adolescent↗
PubMed1979

Complications with retained transvenous pacemaker electrodes.

Out of a series of 1,734 pacemaker patients, the clinical course of 46 patients was reviewed in whom a functionless endocardial electrode was retained. Non-infected electrodes (25 patients) were generally well tolerated without complications, except in one patient who experienced fatal catheter embolism into the pulmonary artery. In cases of infected electrodes (21 patients) a mortality rate of 25% was encountered due to septic complications. Catheter migration was fatal in two out of three patients. It is concluded that entrapped electrode catheters should be removed by thoracotomy if persisting infection is present or if catheter migration has occurred.

Adult↗
PubMed1979

Cardiac effects of angiotensin antagonists in normotensive rats.

1. Angiotensin II (AII) antagonists, namely Sar1,Ile8-AII, Sar1,Ala8-AII and Sar1,Thr8-AII, were administered daily for 4 weeks to normotensive rats to study their effect on cardiac hypertrophy. 2. None of the antagonists altered blood pressure significantly but Sar1,Ile8-AII and Sar1,Ala8-AII produced a significant increase in heart weight, as compared with untreated age-matched control rats. Administration of Sar1,Thr8-AII did not produce cardiac hypertrophy. 3. A significant increase in catecholamine concentration was observed in the ventricles of rats treated with Sar1,Ile8-AII and Sar1,Ala8-AII but no change was found in the group treated with the Sar1,Thr8-AII analogue. The production of cardiac hypertrophy by Sar1,Ile8-AII was prevented by bilateral adrenalectomy, suggesting an important role for catecholamines in modulating cardiac hypertrophy.

Angiotensin II↗