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Biomedical subjects

T David

Publications and source records attributed to T David.

At least 109 records · Page 6Linked to original sources
PubMed1988

[Terson's syndrome. Apropos of 7 cases].

We studied seven cases of Terson's syndrome, in association with bleeding in the subarachnoid space caused by rupture of vascular malformation or cranial traumatism. The association of rapid increase of intracranial pressure with subarachnoid hemorrhage could explain the development of a Terson's syndrome. The retinal hemorrhages associated with the vitreous hemorrhage are variable in morphology and topography. Pars plana vitrectomy has been performed in eight eyes with most often good results.

Adolescent↗
PubMed1988

Digoxin-cyclosporine interaction: severe digitalis toxicity after cyclosporine treatment.

Digoxin toxicity developed in two patients awaiting cardiac transplantation upon the initiation of cyclosporine. Toxicity was associated with elevated digoxin concentrations (10.6 and 5.7 nmoles/L), gastrointestinal symptoms, and arrhythmias classic for digoxin toxicity (bidirectional ventricular tachycardia and AV nodal block with accelerated junctional rhythm respectively). A previously unreported drug interaction between cyclosporine and digoxin was suspected and digoxin pharmacokinetics were studied in two additional patients both before and after cyclosporine therapy prior to cardiac transplantation. The study confirmed a significant interaction between cyclosporine and digoxin; the apparent volume of distribution of digoxin decreased by 71% and its plasma clearance decreased by 53%. Until further information regarding the cyclosporine-digoxin interaction is available, this combination should be used with great caution.

Coronary Disease↗
PubMed1985

[Lumbar arthrodesis: results after more than 10 years].

Two hundred and seventy four patients had a lumbar spine fusion between 1949/1971. Seventy-five of them were available for review more than 10 years after the procedure. There were twenty spondylolisthesis, forty-eight degenerative discopathies, six cases of Pott's disease and one benign tumour. All the patients had been treated conservatively before the surgical procedure for an average of 7 years and were still complaining of chronic low back pain. All the cases reviewed had fused. The functional results were not related to the surgical technique, which varied during this period: eight posterior mid-line grafts, seventeen interbody fusions and fifty combined anterior and posterior approaches sometimes used because of a primary failure of fusion and no postero-lateral fusions. The average follow-up was 13 years with a range from 10 to 26 years. The clinical results were satisfactory in 74 p. 100 of the cases. There were thirteen failures. Seven of these patients had been operated on before the era of systematic preoperative discography and psychological evaluation and the failure was primary. Other failures were observed at about the tenth post-operative year. The results were better in spondylolisthesis with isthmic lesions, rather than in degenerative spondylolisthesis. They were better in pure low back pain than when the pain associated with sciatica. They were better when fusion was limited to one or two levels. Radiographs ten years after the procedure frequently showed evidence of degenerative lesions of the disc above the level of the fusion and, at the same time, some slipping of the upper vertebra. Fortunately, there was no correlation between the radiological appearances and the clinical results.

Adolescent↗
PubMed1985

[Femoral lengthening by transverse diaphyseal osteotomy. Experimental study in the dog].

Previous work has shown that extensive areas of bone necrosis developed after Z-osteotomies of the femoral shaft. A study was made on 11 dogs to compare the effects of a transverse osteotomy followed by immediate lengthening, stabilisation by plates and bone grafting. The bone vitality was studied at 8 and 16 weeks by histological sections and angiography. Attention was focussed on the area of lengthening and the bone ends. The results showed the superiority of transverse osteotomy over Z-osteotomy. Bone necrosis diminished at the 16 th week. In the area of lengthening, the vascularity of the grafts was satisfactory. In contrast, the tendons of the Z-osteotomy showed constant necrosis.

Animals↗
PubMed1979

Aorta-coronary bypass in a patient with sickle cell trait.

A triple aorto-coronary bypass was performed in a patient with sickle cell trait. Partial exchange transfusion with normal packed erythrocytes was used in preparation of the patient for extracorporeal circulation, hypothermia and cardioplegic arrest.

Anemia, Sickle Cell↗
PubMedDate not supplied

Baseline cardiac troponin I in patients on maintenance dialysis.

INTRODUCTION AND OBJECTIVES: There have been conflicting reports in the medical literature regarding baseline levels of cardiac troponins and their usefulness as specific markers of acute myocardial injury in patients on maintenance dialysis. Hence we undertook a study of the normal range of baseline cardiac troponin I (cTnI) in patients on maintenance dialysis in our center. METHODOLOGY: Seventy-five patients aged 45 years or more on maintenance dialysis for at least 1 month were included in the study. None had had an acute cardiac event requiring admission to the hospital during the preceding month. Samples of blood were collected and cTnI levels were estimated using an immunoenzymatic assay (Access Immunoassay system, Beckmann). Correlation of cTnI with gender, age, body mass index (BMI), and adequacy of dialysis (Kt/v) were also done. RESULTS: Forty-six (61.3%) patients were on maintenance hemodialysis and 29 (38.6%) were on peritoneal dialysis. Twenty-four (32%) were over the age of 65 years and 37 (49.3%) were men. Levels of cTnI ranged from 0.000 to 0.568 ng/mL, with mean of 0.040 +/- 0.080. Only six (8%) had levels above 0.1 ng/mL, which was the cut off level for significance in our laboratory. There was no statistically significant correlation of cTnI levels with gender, age, BMI, or Kt/v. CONCLUSIONS: Baseline cTnI levels were below significant levels in the majority of maintenance dialysis patients aged at least 45 years or more. Hence cTnI can be used as a valid marker of acute myocardial injury in this group of patients.

Aged↗
PubMedDate not supplied

Assessing clot lysis strategies using a simplified mathematical model.

This paper attempts to describe lysis of a clot by infusion of lytic agent using a simple geometrical approach, in which the rate of clot lysis is assumed proportional to the exposed surface of the clot and the concentration of lytic agent. Six simple realizations (a)-(f) of this basic model are developed which account for the dependence of clot lysis time on five different clot geometries. In all six cases the clot is initially described as a uniform cylinder which totally occludes a vessel. In model (a) lysis proceeds as an advancing front at the proximal face of the clot. In model (b) lysis proceeds radially outwards from the central axis of the vessel while in model (c) lysis occurs radially inwards from the surface adjacent the wall, of the cylinder. In models (d) and (e) it is assumed that the clot breaks into a uniform spherical and cylindrical fragments, respectively, while model (f) uses the spherical fragment model combined with a lytic agent concentration which decreases with time. The validity of the models was assessed using previously published data from 76 patients in whom lysis time and clot size were recorded. Least squares linear regression analysis based on the six model equations yielded highly significant correlation coefficients r2 of 0.457, 0.412, 0.412, 0.495, 0.469, 0.663 for models (a)-(f), respectively. The results suggest that when a constant lytic agent concentration is assumed, no single geometry accounts for significantly more variation than any other, but that a combination of varying lytic agent concentration and clot geometry significantly influences clot lysis time and accounts for much of the observed variation.

Humans↗