Search PubMed⌕ Search

Biomedical subjects

M Gent

Publications and source records attributed to M Gent.

At least 181 records · Page 10Linked to original sources
PubMed1979

The influence of red blood cells on the effects of aspirin or sulphinpyrazone on platelet adherence to damaged rabbit aorta.

The effects of acetylsalicylic acid (ASA; aspirin) or sulphinpyrazone (SP) on the adherence of washed rabbit platelets to the subendotheilial surface of an everted aorta mounted on a probe or to the subendothelial surface of a rabbit aorta attached to a perfusion apparatus were examined. ASA had no effect on platelet adherence to a damaged aorta perfused with a suspension of washed platelets in a medium containing 10% red blood cells (RBC); SP was slightly inhibitory at high concentration. When damaged rabbit aortae were everted on a probe and rotated in a suspension of washed platelets to which RBC were added to a packed cell volume of 10%, both ASA and SP inhibited platelet adherence to the damaged vessel wall. When the PCV was 40%, ASA was not inhibitory and SP reduced platelet adherence only at very high concentrations. It is therefore unlikely that, at the concentrations achieved in man, SP exerts an effect on platelet adherence. The different effects of ASA and SP on platelet survival do not appear attributable to their effects on platelet adherence.

Animals↗
PubMed1977

Resolution of lipid-containing atherosclerotic lesions induced by injury.

In previous experiments, injury-induced atherosclerosis has been shown to be associated with the development of fatty streaks. The findings suggested that fatty streaks might represent a stage in healing of intimal injury evolving to fibrous plaques, free of lipid. The present experiment was designed to study the incidence and evolution of these lesions during a 2-week period of lesion retrogression following removal of a catheter placed in the aorta for 1 week. The findings indicate that as fat-containing lesions, either of the thromboatherosclerotic or fatty streak varieties, decreased, the amount of nonlipid-containing fibrous lesions increased.

Animals↗
PubMed1977

Relationship between acute respiratory illness and air pollution levels in an industrial city.

A retrospective study relating air pollution levels to hospital admissions for acute exacerbations among adults with chronic respiratory illness and children with acute respiratory disease was carried out in a highly industralized Canadian city. A total of 1,780 patient records were collated, and daily, weekly, and monthly hospital admission rates were related to a standard air pollution index that took into account floating particles and sulfur dioxide. A correlation coefficient of 0.77 (P less than 0.01) between number of admissions and level of air pollution was found for the city as a whole, and the strength of the association varied inversely with the distance of the hospital from the industrial area.

Acute Disease↗
PubMed1977

The effect of thrombocytopenia on experimental arteriosclerotic lesion formation in rabbits. Smooth muscle cell proliferation and re-endothelialization.

This study was designed to investigate the mechanisms involved in fibromusculoelastic lesion formation produced by selective de-endothelialization by the intra-arterial balloon catheter technique in thrombocytopenic rabbits. Thrombocytopenia was induced and maintained for up to 30 days by daily injections fo highly specific sheep anti-rabbit platelet sera (APS). Evidence for re-endothelialization was obtained by i.v. Evans blue dye 30 min before sacrifice. Rabbits received daily injections of APS, which reduced the mean platelet count to 5,600/cm3; control animals received identically treated normal sheep sera on the same schedule, and had mean daily platelet counts of 363,000/cm3. Evaluation of intimal thickness was assessed by counting cell layers in semithin sections. Intimal thickening in aortae from rabbits treated with APS was strikingly suppressed, in contrast to those from normal sheep sera-treated animals which showed a mean intimal thickness of 18 cell layers within 28 days often after de-endothelialization. Re-endothelialization was not affected by APS treatment. These results indicate that the proliferation of smooth muscle cells is dramatically inhibited by reduction of platelets.

Animals↗
PubMed1977

Significance testing to establish equivalence between treatments, with special reference to data in the form of 2X2 tables.

In this paper, the role of significance testing in establishing equivalence between treatments is described. In place of the more customary null hypothesis of no difference between treatments, the hypothesis that the true difference is equal to a specified delta is tested. The particular case of comparing two binomial samples is described in detail. Results using a method due to Gart and approximations based on the chi2 and normal distributions are compared. It is found that the test based upon chi2 with continuity correction agrees best overall with Gart's (1971) test and is therefore recommended for use when computational facilities needed for carrying out the latter are not available.

Biometry↗
PubMed1977

Clomipramine (Anafranil) in depressive patients with obsessive neurosis.

The authors express the view that, clinically, clomipramine (Anafranil, Geigy Pharmaceuticals) seems to be the treatment of choice for obsessive-compulsive illness. Clomipramine possesses a specific anti-obsessional property which is distinct from its antidepressant property. The optimal therapeutic dose from this study appears to be in the range of 175 mg to 225 mg a day. Minor reversible adverse reaction gradually decreases with the increase of duration of treatment.

Adult↗
PubMed1977

Relationship between the anticoagulant and antithrombotic effects of heparin in experimental venous thrombosis.

The relationship between the antithrombotic and anticoagulant effects of heparin was assessed using venous thrombi in rabbits. Accretion of 125I-fibrinogen onto jugular vein thrombi was used to assess the antithrombotic effect of heparin, and the protamine sulfate titration test (heparin activity) and the activated partial thromboplastin time (APTT) were used to measure its anticoagulant effect. The effect of heparin on jugular vein bleeding times was also measured in a separate group of animals. Fibrinogen accretion was significantly lower with continuous infusion than with intermittent injection. Heparin, given by continuous infusion, produced marked inhibition of fibrinogen accretion (to less than 10% of control accretion) at an APTT value of between 75 and 80 sec (control 34 sec) and at a level of heparin activity of 0.4-0.5 U/ml. Infusion of cryoprecipitate reduced the effect of heparin on the APTT relative to its effect on heparin activity. In these cryoprecipitate-treated animals, marked inhibition of fibrinogen accretion occurred at a similar level of heparin activity (0.4-0.6 U/ml) but at a significantly lower APTT (35-50 sec) than in normal animals. On the other hand, there was a progressive increase in jugular vein bleeding time with both increasing APTT values and heparin levels in both groups of animals.

Animals↗
PubMed1976

Prevention of venous thrombosis with small, subcutaneous doses of heparin.

The effect of low-dose heparin prophylaxis on venous thrombosis and bleeding after major elective surgery was studied in a prospective controlled study of 820 patients. The total incidence of venous thrombosis detected with leg-scanning using fibrinogen labeled with radioactive iodine (125I) was reduced from 16.0% in the control group to 4.2% in treated patients. More important, the incidence of popliteal or femoral vein thrombosis was reduced from 2.9% to 1.0%. Prophylaxis resulted in a slight increase in bleeding-minor wound hematoma, mean volume of blood transfused, and a post-operative hematocrit fall in treated patients. However, increased bleeding was clinically minor, and prophylaxis was well tolerated.

Fibrinogen↗
PubMed1976

Impedance plethysmography using the occlusive cuff technique in the diagnosis of venous thrombosis.

Impedance plethysmography using the cuff technique has been compared with venography in 346 consecutive patients with suspected venous thromboembolism. The limbs were classified according to the venographic results as no thrombosis, proximal (popliteal, femoral, or iliac) vein thrombosis, and calf thrombosis. A discriminant analysis was performed. The impedance plethysmographic result was normal in 386 of 397 limbs which were normal on venography, a specificity of 97%, and abnormal in 124 of 133 limbs which showed proximal vein thrombosis, a sensitivity of 93%. Seventy-three of 88 limbs with calf vein thrombi and a normal impedance plethysmographic result. The sensitivity in 29 limbs with asymptomatic proximal vein thrombosis was 83%. Impedance plethysmography is an accurate method for detecting proximal vein thrombosis but has limitations which include the possibility of false positive results due to arterial insufficiency and muscle tension.

Adolescent↗
PubMed1976

Regression of injury-induced atheromatous lesions in rabbits.

For four consecutive weeks, 61 rabbits received weekly injections of lymphocytotoxic-positive human serum into the left carotid artery and of autologous serum into the right carotid artery as a control. Serum cholesterol and serum triglyceride levels were measured before the study, in the second and fourth weeks of the study, and weekly thereafter. The results show that repeated intimal injury caused raised, lipid-containing thromboatherosclerotic lesions and that there was a consistent regression to lipid-free fibromusculoelastic plaques from the first week after completion of the injection regimen to the fourth week. Apparently, regeneration of an intact covering cell layer resulted in the elimination of lipid deposits from raised lesions, resulting in lipid-free fibromusculoelastic plaques. In addition, fatty streaks were observed to occur during regression. A statistically significant rise in serum cholesterol level during the phase of progression of lesions and a subsequent fall during regression were observed.

Animals↗
PubMed1975

Emergency department use at two Hamilton hospitals.

This report compares emergency department use at two urban Hamilton hospitals. One mainly serves lower socioeconomic and industrial groups and the other predominantly suburban residents. Although the groups served are different, the patterns of use at both hospitals were found to be similar. Over one third of visits at both are classified as nonurgent. The urban industrial hospital has higher proportions of visits that are nonurgent, by men and due to trauma. However, other parameters such as arrival time, use of ambulance, proportion admitted, percentage of emergencies, percentage of repeat visits, use of radiology and laboratory facilities and proportions of visits in different categories of presenting complaint were similar at the two hospitals. Similarities in use patterns may be due to universal health insurance, for 90% of users have medical insurance and have family doctors.

Adult↗