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At least 1,675 records · Page 93Linked to original sources
PubMed1986

[Beneficial effects of diltiazem in exertion stable angina. Evaluation of coronary hemodynamics during cardiac pacing].

We evaluated the protective effect of Diltiazem from pacing-induced myocardial ischemia in 9 patients (pts) with coronary heart disease (CAD) and stable effort angina by studying the changes in systemic and coronary hemodynamics during pacing. Hemodynamic parameters were evaluated at baseline and at peak pacing before and after Diltiazem, 25 mg i.v. Diltiazem prevented angina in 6 of 7 pts who presented angina in the control pacing. This beneficial effect was accompanied at peak pacing rate by a significant fall in ST depression, arterial pressure, rate-pressure product and left ventricular (LV) end-diastolic pressure, while no significant changes were observed in LV dp/dt max, coronary blood flow and coronary vascular resistance. Therefore, Diltiazem exerts a protective effect from pacing-induced myocardial ischemia in pts with CAD and stable effort angina, without impairing LV function. This beneficial effect is due to a reduction in myocardial metabolic requirements, rather than to an improvement of blood supply to the ischemic myocardium.

Aged↗
PubMed1987

N-butyl hyoscine exerts local spasmolytic effect in the small and large bowel of the conscious dog.

The spasmolytic activity of N-Butyl Hyoscine (NBH) (1) has been investigated in conscious dogs provided with ileal or colonic Thiry fistulas in which motility was stimulated by intraluminal distension. In ileal motility experiments, phasic motility index (PMI), intestinal tonus, contraction frequency and heart rate were monitored. Intravenous administration of NBH (10 to 100 micrograms/kg) depressed PMI (ED50 35.1 micrograms/kg) and the other motility parameters. Heart rate increases were observed at 100 micrograms/kg. Application of NBH directly into the fistula (300 to 3000 micrograms/kg) caused a long-lasting, potent inhibition (31-72%) of PMI; tonus and contraction frequency were only slightly affected, while heart rate was not altered. When NBH was administered into an ileal fistula adjacent to the one from which motility was recorded, changes of PMI and other parameters were observed only after a massive dose of the drug (10000 micrograms/kg). In colonic fistula experiments, intraluminal NBH administration (300 to 3000 micrograms/kg) depressed colonic motility (39-59%), without affecting heart rate. It is concluded that NBH present in the intestine, although poorly absorbed, exerts local spasmolytic action.

Animals↗
PubMed1986

In vitro release of physically separable factors from monocytes that exert opposing effects on erythropoiesis.

In order to investigate the capacity of monocytes to release erythroid burst-promoting activity (BPA), we added media conditioned by homologous monocytes to both serum-free human and serum-restricted murine marrow culture. We found that soluble, membrane vesicle-free culture medium is a potent source of the growth factor. On the other hand, monocyte membranes or exfoliated plasma membrane vesicles elaborate a factor that inhibits erythroid burst formation by up to 100%. Inhibitory activity is expressed in a dose-dependent fashion over a wide range of concentrations (0.001 to 10 micrograms/mL) tested. Experiments with antilymphocyte plasma membrane IgG, which has been shown to neutralize both soluble and membrane-bound lymphocyte-derived BPA in human marrow culture, indicate that the expression of soluble BPA by monocytes is unaffected by these antibodies. Furthermore, while antimembrane IgG is capable of absorbing BPA from LCM supernatants, these antibodies are ineffective in removing BPA from MCM supernatants, suggesting that these two soluble growth factors may be antigenically distinct. Our findings indicate that while monocytes release soluble BPA, they are also a source of membrane-associated factors that exert inhibitory effects on erythropoiesis in vitro.

Animals↗
PubMed1985

[Myocardial ischemia induced by the cold pressor test in patients with exertion angina. Case contribution].

The aim of the present study was to assess the incidence of myocardial ischemia during cold pressor test in patients with stable exertional angina pectoris. Thirty-seven patients with proven coronary artery disease were submitted to cold pressor and exercise stress testing; computer assisted electrocardiographic recordings were obtained throughout the examinations. Cold stimulation provoked electrocardiographic signs of subendocardial ischemia only in 3 patients. They had suffered of a previous myocardial infarction and showed low exercise tolerance and severe coronary lesions (one with triple vessel and 2 with left main disease). Interestingly, only one of these patients gave an history of angina during cold exposure. Thus these data indicate that chest pain and electrocardiographic signs of ischemia are an uncommon event during cold pressor stimulation which occurs more likely in patients with fairly severe coronary narrowings. More sensitive markers of ischemia and/or different modalities of cold application are required for studies concerning the relationship between cold exposure and angina pectoris.

Angina Pectoris↗
PubMedDate not supplied

[Antagonistic effect against "Clostridium perfringens" exerted in the digestive tract of gnotobiotic mice by "Clostridium" strains isolated from the microflora of conventional mice (author's transl)].

Bacterial strains isolated from the digestive tract of conventional mice produced a barrier effect against a strain of Clostridium perfringens type A (strain CP) in the gastrointestinal tract of gnotobiotic mice. This barrier effect was observed when mice, monoassociated with Escherichia coli K12, were inoculated with a mixed culture of fusiform-shaped clostridia. The collection of fusiforms (collection D) was obtained from a single colony chosen from among the 26 types studied. Collection D and E. coli K12 together exerted a barrier effect against all strains of C. perfringens type A tested. No effect was observed against a C. perfringens type C strain. The expression of the barrier effect depended on the order in which the strains were used to inoculate the mice. Thus strain CP was eliminated from the digestive tract when the mice had previously been associated with collection D and E. coli K12. If the mice were inoculated with strain CP first, however, the barrier effect was only partial. We have also been able to use two strains of clostridia (C1, C3) instead of E. coli K12 to produce a drastic barrier effect against strain CP. The order in which the strains were used to inoculate the mice did not, in this case, influence the production of a barrier effect. Three strains (Da, Db, Dc) isolated from collection D, produced only a partial barrier effect against strain CP in mice previously associated with E. coli K12. These results illustrate the difficulties encountered in determining the minimal number of bacterial strains involved in the production of a barrier effect.

Animals↗
PubMed1984

The glutamate analogue alpha-aminoadipic acid is taken up by astrocytes before exerting its gliotoxic effect in vitro.

DL- and L-alpha-aminoadipic acid (alpha-AA) are specific gliotoxins in vitro (Huck, S., F. Grass, and M. E. Hatten (1984) Neuroscience 12: 783-796). By combining immunohistochemical and autoradiographic techniques, we now show that DL-[14C]-alpha-AA is accumulated almost selectively by astrocytes in cultures of the dissociated postnatal mouse cerebellum, presumptive neurons being free of the radiolabel. High pressure liquid chromatography analysis of cultures incubated with D- or L-alpha-AA and DL-[14C]-alpha-AA autoradiograms conducted in the presence of D- or L-alpha-AA reveal a stereospecificity of astroglial L-alpha-AA uptake. Both the uptake of alpha-AA by astrocytes and alpha-AA-induced gliotoxicity were sodium dependent. Since 2 microM tetrodotoxin did not prevent the morphological changes, we conclude that sodium plays its role in alpha-AA-induced gliotoxicity by mediating the transport of the substance. Thus, alpha-AA appears to be taken up by the astrocytes before exerting its cytotoxic effect.

2-Aminoadipic Acid↗
PubMed1983

The surgical treatment of exertional compartment syndrome in athletes.

We studied the cases of twelve patients who had bilateral exertional compartment syndrome involving one or all of the compartments of the lower extremities. The patients were divided into three groups based on the clinical findings. Group I consisted of seven patients with symptoms involving the anterior or lateral compartments only; Group II, of three patients with involvement of the deep posterior compartments alone; and Group III, of two patients with involvement of both the anterior and deep posterior compartments. On the basis of their clinical signs and symptoms each patient underwent dynamic tissue-pressure measurements using a slit catheter before, during, and for as long as thirty minutes after exercise. All patients had elevated resting and peak-to-peak dynamic pressure measurements. Treatment consisted of bilateral compartmental fasciotomy, as indicated. All of the patients in Group I had complete relief of symptoms; however, one patient in Group II and one in Group III had a recurrence of symptoms in the deep posterior compartment.

Adolescent↗
PubMed1983

[Molsidomine in exertion angina].

Molsidomine (M), a new anti-angina drug, was studied by stress tests in 50 cases of stable angina and clinically in 33 patients not controlled by beta-blockers. One hour after sublingual administration of 2 mg of M. to 10 patients, the work required to cause ST depression of 1 mm (WST1) was increased by 94 per cent (p less than 0.005), the total work was increased by 52 per cent (p less than 0.005) and the maximal ST depression (ST max) was reduced by 45 per cent (p less than 0.01). The resting heart rate was unchanged and the blood pressure dropped mildly. In 4 of the 10 patients with exertional angina even while taking beta-blockers, the synergistic effect of M was remarkable. With a sublingual dose of 1 mg, the WST1 and the ST max are very significantly improved. The effect is even more marked at a dose of 2 mg. With a sublingual or oral of 2 mg, WST1 and ST max are very significantly improved at 1 hour and at 3 hours (p less than 0.005). Data from the literature show a significant anti-ischaemic effect until the 6th hour. In two series of 10 patients, 2 mg of M administered orally were compared to 20 mg of isosorbide dinitrate and to 10 mg of nifedipine at the 2nd hour. The WST1 and ST max were very significantly improved by all three drugs to a similar degree.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1981

[Hygienic and microbiological influences exerted on natural water biotopes by algae and the growth of water plants. 1. Communication: antibacterial properties of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) in vitro (author's transl)].

The growth-inhibiting behaviour of abacterial, liquid pure cultures made up of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) which were made to grow profusely in special culture containers under constant exposure to light and ventilation was examined in ten different species of microorganisms during a period of contact of 4 days both in the light and in the dark. Subjected to the test were the 5 pathogenic species Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, Salmonella typhimurium and Candida albicans as well the 5 bacterial contamination indicators E. coli (faecal indicator), Streptococcus faecalis (enterococci), Enterobacter aerogenes ("coliforms"), Staphylococcus epidermidis (dermic germ) and Bacillus subtilis ("contamination germ"). It was found that --Hydrodictyon reticulatum and Aphanothece nidulans exert a strong antibacterial effect, while Chlorella vulgaris provides no indication of a bacterial growth-inhibiting effect. --this antibiosis is linked with the assimilative activity of the algal cultures, as in the dark no antibacterial action is discernible --the "antibiotic principle" must be liable to transitory or rapid disintegration because the algal cultures are ineffective in the dark and also culture filtrates of 5-days old algal cultures exercise no growth-inhibiting effect. With respect to the sanitation of waters it is important to state that a profuse growth of algae produces a certain, but hardly reliable "biological water disinfection" and renders difficult the assessment of the quality of a water-course as a result of the elimination of the usual contamination indicators. Therefore, additional microbiological quality parameters must be used for assessment of pollution of swimming pools with strong algal growth.

Bacillus subtilis↗
PubMedDate not supplied

Interference between two immune responses. II.--Conferrability by the serum of the influences exerted by a response to horse RBC on the subsequent response to sheep RBC in the mouse.

Serum taken from mice responding to HoRBC and given to syngeneic mice influences the kinetics of a subsequent anti-SRBC response. The serum taken at the 36th of the anti-HoRBC response exerts after transfer an accelerating effect on the anti-SRBC response while this of the 7th day has an inhibitory effect. Both effects are especially demonstrative on mice irradiated and restored with spleen cells from a single donor because of the low variation coefficient of their anti-SRBC response.

Animals↗
PubMed1982

Cyclosporin-A and the OKT3 monoclonal antibody exert their respective inhibitory and mitogenic activity on T cells by interacting with the same receptors.

Cyclosporin-A strongly suppressed proliferation of T cells induced by the OKT3 monoclonal antibody when added at the beginning of the cultures but not when added 72 hr later. The inhibitory activity of Cyclosporin-A became apparent during the first 48 hr and was maintained throughout the culture period. Cyclosporin-A significantly inhibited binding of OKT3, but not OKT4 or OKT8, antibodies to T cells as determined by indirect immunofluorescence microscopy. In addition, Cyclosporin-A suppressed the killing of 51Cr labelled T cells mediated by OKT3 antibody plus complement, whereas Cyclosporin-A did not alter the lysis of T cells by OKT4 antibody plus complement treatment. These results strongly suggest that Cyclosporin-A and OKT3 antibody exert their respective suppressive and mitogenic activity on T cells by interacting with the same receptor.

Antibodies, Monoclonal↗
PubMed1981

Inhibitory effect on bone formation and calcification exerted by the anti-inflammatory drug ibuprofen. An experimental study on adult rat with fracture.

The anti-inflammatory drug ibuprofen (2-(4-isobutylfenyl)propionic acid) was administered to adult male rats for 10 weeks in daily oral doses of 16 mg. Fractured and unfractured tibias were studied during 4 to 10 weeks' treatment by the use of microradiography, fluorescence labelling and biochemistry. New bone formation was observed to be inhibited on endosteal surfaces of the tibia when treated with ibuprofen, which also diminished the amount of cortical bone (almost significantly). However, the bone area and the new bone formation of periosteal callus and on periosteal surfaces of tibia was not influenced by the treatment. The chemical composition of fractured and unfractured bone was significantly altered and showed a reduced ratio of hydroxyproline/nitrogen as well as an inhibition of calcification of bone matrix with a reduced calcium/nitrogen ratio followed by an increased ratio of hexosamine/DNA and RNA-ribose/DNA after treatment with ibuprofen. The inhibition of new bone formation and calcification of bone in adult rat exerted by ibuprofen may be explained as a direct effect on bone-forming cells on endosteal bone surfaces.

Animals↗
PubMed1981

Acute arterial hypertension during spontaneous angina in patients with fixed coronary stenosis and exertional angina: an associated rather than a triggering phenomenon.

The role of systemic arterial hypertension as a possible trigger of myocardial ischemia during angina at rest was studied in 13 consecutive patients who also had a history of exertional angina. Significant (greater than or equal to 70%) stenosis of at least one major vessel was present in each of the 10 patients in whom coronary arteriography was carried out. After documentation of the electrocardiographic and arterial blood pressure changes during two or more episodes of resting angina, i.v. methoxamine was infused under continuous monitoring of the ECG, arterial blood pressure and pulmonary artery diastolic pressure. The heart rate was maintained either spontaneously or by atrial pacing to levels similar to those during angina at rest. Despite increases in arterial blood pressure and the double product (systolic blood pressure x heart rate) to levels higher than those during spontaneous angina in all patients, no chest pain or electrocardiographic changes occurred in nine patients. In the other four patients, however, angina supervened. Three of these four patients, but only one of the remaining nine, had a borderline or elevated pulmonary artery diastolic pressure at rest. We conclude that in a considerable number of patients with "nonvariant" resting angina, acute increases in arterial blood pressure during the spontaneous attacks are not likely to be the cause of myocardial ischemia. Nevertheless, in some of these patients, increases in resting pulmonary artery diastolic pressure may favor the development of ischemia during afterload augmentation.

Acute Disease↗
PubMed1980

A study of the lateral wall pressure exerted by balloon-tipped catheters.

A technique was developed for assessing the lateral wall pressure exerted by balloon-tipped catheters. It was found that (1) high intraballoon pressures do not produce high lateral wall pressures in a minimally constricting lumen; (2) inflation of the balloon by partial compression of a large initial volume of air results in a much more compressible balloon and produces markedly less arterial distortion; and (3) use of the catheters inflated in this way is effective clinically. Therefore, instead of the usual technique, we recommend inflation of the embolectomy balloon by partial compression of a comparatively large initial volume of air in the syringe.

Air↗
PubMed1980

Morphine exerts testosterone-like effects in the hypothalamus of the castrated male rat.

Previous research has indicated that endogenous opioids participate in the regulation of activity in the hypothalamic-pituitary-luteinizing hormone (LH) axis and mediate the negative feedback control exerted by testosterone. If this assumption is correct, then two predictions can be made. First, the effects of testosterone should be competitively inhibited by narcotic antagonists; and, second, opiates should mimic the acute and chronic effects of testosterone in the castrated male rat. The results of the present investigations support both of these predictions. We found that naloxone competitively antagonized the depressive effects of testosterone on serum LH in the castrated rat and, conversely, that testosterone competitively antagonized the LH-releasing properties of naloxone. In addition, morphine and testosterone both depressed serum LH levels in a dose-dependent fashion in the acutely castrated animal. Moreover, morphine was just as effective as testosterone in reversing the castration-induced fall in hypothalamic-LH-releasing hormone (LH-RH), which occurs in the chronically castrated male rat. On the other hand, morphine failed to reverse the long-term changes in pituitary LH content and increase in serum LH, which is consistent with prior observations that morphine affects only the hypothalamic aspect of the hypothalamic-pituitary-LH axis in the male rat. These results, thus, support the concept that an as yet unidentified opioid-containing neuronal system regulates activity in the hypothalamic-pituitary-LH axis and mediates the effects of testosterone on this axis.

Animals↗
PubMed1995

Polyamines exert regulatory control on mycobacterial transcription: a study using RNA polymerase from Mycobacterium phlei.

We have used purified RNA polymerase from Mycobacterium phlei to study the role of polyamines in mycobacterial transcription. Both initiation and elongation phases of the process were affected biphasically by polyamines. Interaction of polyamines with DNA template plays an important role in transcription modulation. Our studies emphasize that polyamines can exert a regulatory control on mycobacterial transcription.

DNA-Directed RNA Polymerases↗
PubMed1995

Exertional heatstroke: a preventable condition.

Exertional heatstroke is a syndrome occurring in the young and active population when homeostatic thermoregulatory mechanisms are unable to meet the demands of heat stress. In most cases its occurrence is sporadic and it is regarded as an extreme medical emergency that might result in death if not immediately diagnosed and properly treated. Following some simple regulations and providing proper instructions have proven efficient in preventing this serious disease.

Adolescent↗
PubMed1995

Chronic (exertional) compartment syndrome of the legs diagnosed with thallous chloride scintigraphy.

Over the past 4 yr, we obtained 201Tl lower leg scans on 14 patients with suspected chronic exertional compartment syndrome. Qualitative assessment of the images revealed that 12 scans showed reversible compartment ischemia. Retrospective quantitation confirmed redistribution in seven of nine patients. Seven patients had surgery with partial or complete resolution of their symptoms.

Adolescent↗