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Biomedical subjects

S M Rajah

Publications and source records attributed to S M Rajah.

At least 37 records · Page 2Linked to original sources
PubMed1980

Seronegative pauciarticular arthritis and HLA B27.

Twenty-six patients with a pauciarticular arthritis have been studied clinically, radiologically and with histocompatibility typing. An increased frequency of HLA B27 was found (p = 1.87 x 10(-12)). Low back and buttock pain, Achilles tendinitis and dactylitis of the toes were more frequent in HLA-B27 positive patients. It is suggested that histocompatibility testing may be of some value in diagnosis and in the investigation of the possible 'reactive' nature of this type of arthritis.

Adolescent↗
PubMed1980

Chronic haemolysis after Lillehei-Kaster valve replacement. Comparison with the findings after Björk-shiley and Starr-Edwards mitral valve replacement.

Nineteen female and sixteen male patients who have had their heart valves replaced with Lillehei-Kaster valves were investigated for haemolysis four to 18 months after operation. Investigation included serum lactic dehydrogenase, serum haptoglobins, and urine haemosiderin. Red cells survival, using autologous red cells labelled with 51Cr, was measured in 12 patients. No patient showed manifest anaemia. The serum lactic dehydrogenase levels were raised in 66% of the mitral valve patients, 81% of the aortic valve patients, and in all the double valve patients. The serum haptoglobins were decreased in 66% of mitral patients, 68% of aortic valve patients, and in 75% of the double valve patients. All the 12 patients studied had lower than normal red cell survivals. No correlation was found between the incidence of haemolysis and the size of the valve. In isolated mitral valve replacement 66% showed compensated haemolysis compared with 42% in Björk-Shiley valves (p less than 0.05), 85% in Starr-Edwards valves (composite seat) (p less than 0.01), and none in frame-mounted irradiated homografts (previous study) (p less than 0.001).

Female↗
PubMed1980

Antithrombotic therapy for vascular prosthesis: an experimental model testing platelet inhibitory drugs.

Although Dacron vascular grafts are widely used, they are thrombogenic and rapid blood flow maintains patency. When blood flow is suboptimal, antithrombotic therapy may prevent early occlusion. We evaluated the effect of three platelet inhibitory drugs: acetylsalicylic acid (ASA), dipyridamole (DPM), sulphinpyrazone (SPZ), and a combination of ASA plus DPM on platelet adherence to woven Dacron in an artificial circulation. Heparinized blood from 18 volunteers was divided equally for test and control circuits, and to the test each drug was added in therapeutic concentration. The experiment was repeated ex vivo using blood donated by six volunteers after each had taken, separately for 1 week: (1) no drug; (2) ASA, 300 mg, three times a day; (3) DPM, 100 mg, four times a day; (4) SPZ, 200 mg, four times a day; (5) ASA, 300 mg, plus DPM, 75 mg, combined, three times a day. Platelet count, adhesion and aggregation were measured during the 60-minute perfusion, and scanning electron miscroscopy of the graft's luminal surface was performed. ASA was the most effective single agent, significantly impairing platelet function and reducing consumption of platelets by the graft. DPM reduced platelet adherence only in the ex vivo experiment, and its addition to ASA imparted no further influence. Sulphinpyrazone had little effect in either experiment. Antithrombotic therapy with ASA and DPM requires clinical evaluation.

Aspirin↗
PubMed1979

The interaction of varying doses of dipyridamole and acetyl salicylic acid on the inhibition of platelet functions and their effect on bleeding time.

1 In normal volunteers maximum reductions in platelet functions, collagen aggregation, adhesion and PF4 availability, were achieved using combined doses of 50 mg three times daily dipyridamole + 180 mg ASA or 75 mg three times daily dipyridamole + 120 mg ASA daily. 2 These doses did not prolong the bleeding time. 3 A synergistic effect has been demonstrated with 25 mg dipyridamole three times daily and 60 mg ASA. 4 At higher doses the effects on platelet functions were additive up to the maximal response. 5 The effect of low doses of ASA on platelet function was cumulative. 6 As lower doses of ASA in the combination studied inhibit platelet functions maximally without altering the bleeding time and probably without inhibiting prostacyclin, we suggest that these combinations of dipyridamole and ASA merit consideration in future clinical trials.

Adult↗
PubMed1979

Effect of intrauterine contraceptive device on uterine haemostasis: a morphological study.

The effect of the intrauterine contraceptive device (IUCD) on uterine haemostasis was studied at various stages of the menstrual cycle in a series of 46 patients by light- and electron-microscopy and by following the distribution of an infusion of 51Cr-labelled autologous platelets. The endometrium in contact with the IUCD in the majority of cases showed grooving with atrophy and mild chronic inflammation in the surrounding tissues. The adjacent stroma also showed increased vascularity and occasional foci of haemorrhage but the increased blood loss associated with the presence of the IUCD could not be attributed to mechanical erosion or stromal blood vessels by the device. During menstruation the presence of an IUCD does not appear to inhibit the formation of fibrin/platelet thrombi although both in control and IUCD patients there was a striking paucity of platelet/fibrin thrombi in circumstances where their formation should be enhanced. In contrast to other workers we have not observed that gaps or breaks in the endothelial lining of endometrial blood vessels occur with any greater frequency in patients fitted with an IUCD. The principal mechanism by which uterine haemostasis is achieved remains to be established.

Adult↗
PubMed1979

Heparin administration during extracorporeal circulation: heparin rebound and postoperative bleeding.

The individual variations in heparin dose response and heparin activity decay have indicated limitations of the protocols based on body surface area and weight of the patients. In the present study the heparin levels and simpler clotting tests were monitored in a consecutive series of 71 patients undergoing standard cardiac operations. The clotting tests used were the Celite activated clotting time (Celite ACT) and the whole blood activated recalcification time (BART). Forty-four patients received a loading dose of heparin, 3 mg. per kilogram, a maintenance dose of heparin, 1.5 mg. per kilogram per hour, and 6 mg. of protamine sulfate per kilogram at the termination of extracorporeal circulation (ECC) (Protocol I). Twenty-seven patients received a similar initial dose, but the maintenance dose of heparin and the dosage of protamine sulfate were administered according to the measured heparin levels (Protocol II). A significant difference was seen in the measured heparin levels (p less than 0.01, Celite ACT (p less than 0.01), and BART (p less than 0.01) in patients on Protocols I and II. Ten of the 24 patients on Protocol I and none on Protocol II showed heparin rebound phenomenon, and blood loss in patients on Protocol I was significantly greater than that in patients on Protocol II. The study clearly demonstrates that our protocol of heparin administration and control with simpler tests ensures safe hypocoagulation during ECC and efficient reversal at the end, with minimal postoperative blood loss.

Adolescent↗
PubMed1978

Heparin-like activity in uterine fluid.

Uterine fluid was collected from a group of normal patients and a group of patients with menorrhagia. Heparin-like activity was detected in 34 out of 38 samples using an anti-Xa heparin assay. The heparin-like activity in uterine fluid was inhibited by adding the heparin antagonist hexadimethrine bromide to the assay. Concentrations of fibrinogen-fibrin degradation products (FDPs) were measured in five samples of uterine fluid. FDPs in the concentration detected had no effect on the anti-Xa assay. Heparin-like activity was higher in the group with menorrhagia, although the differences were not significant. Heparin-like activity increased throughout the menstrual cycle and decreased during menstruation, suggesting a possible cyclical variation in activity. There was no correlation between mast cell numbers in the endometrium and myometrium and heparin-like activity in uterine fluid and no correlation between the numbers and the stage in the menstrual cycle. In a few patients with intrauterine contraceptive devices (IUCDs) heparin-like activity was increased.

Body Fluids↗
PubMed1978

Evaluation of the thrombogenic potential of three types of arterial graft studied in an artificial circulation.

The thrombogenic potential of woven Dacron, expanded polytetrafluoroethylene (Gore-Tex) and gluteraldehyde-treated human femoral artery (HFA) grafts was evaluated using an artificial circulation. The differences in the platelet parameters (platelet count, adhesion and aggregation) and scanning electron microscopy (SEM) appearances before and after perfusion were used as indices of thrombogenicity. Platelet counts fell significantly with woven Dacron, moderately with HFA and no fall was observed with Gore-Tex. Platelet aggregation was unaffected by any graft, but platelet retention was significantly marked in woven dacron. SEM studies revealed minimal adherence of platelets to Gore-Tex and HFA endothelium, but marked adherences to woven Dacron, accompanied by morphological changes of the adhered platelets. In an artificial circulation, of the three types of arterial graft, woven Dacron has the greatest influence on platelet function, indicating significant thrombogenicity, whereas HFA is intermediate in its effect and Gore-Tex appears to have the lowest thrombogenic potential.

Blood Cell Count↗
PubMed1978

Histocompatability antigens and schizophrenia.

The HLA (Human Leucocyte Antigen) types and B were studied in 80 patients diagnosed as schizophrenic. There was an increased incidence of HLA-BW5 and a decrease in HLA-AW29 and HLA-BW17 as compared with healthy controls. In the sub-group of patients exhibiting Schneider's first-rank symptoms there was an increased incidence of HLA-A1 with a decrease in HLA-A2 and HLA-BW17.

Female↗
PubMed1977

Coagulation changes in sensitized canine renal allografts.

Coagulation changes within kidney homotransplants to sensitized canine recipients have been studied by assessing the arteriovenous gradients of formed blood elements and coagulation factors across the organ. It is confirmed that hyperacute rejection is accompanied by evidence of intravascular coagulation within the graft, which is maximal during the first 20 minutes after revascularization. Attempts were made to prolong the survival of the grafts by the use of cytotosine arabinoside, methylprednisolone, heparin and azathioprine. In some instances, the severity of the intravascular coagulation was reduced but it did not prove possible to extend the survival of the kidneys beyond 24 hours.

Animals↗