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Biomedical subjects

M S Valiathan

Publications and source records attributed to M S Valiathan.

At least 19 recordsLinked to original sources
PubMed1992

Paradoxical effect of cerium on collagen synthesis in cardiac fibroblasts.

The present study examined the effect of cerium on collagen synthesis in cultured cardiac fibroblasts and explants. At 100 nM, a concentration comparable with that found in the cardiac tissue of patients with endomyocardial fibrosis, the element was found to enhance the incorporation of tritiated proline into collagen and non-collagen proteins while at 10 microM, it had an inhibitory effect. Cerium was found to have no effect on rates of DNA synthesis in fibroblasts at 100 nM. However, at this concentration, the element markedly enhanced the incorporation of tritiated uridine into RNA, suggesting that cerium may act at the level of transcription to stimulate collagen and non-collagen protein syntheses. The stimulatory action of very low levels of cerium on collagen synthesis may contribute to the accumulation of collagen seen in endomyocardial fibrosis.

Animals↗
PubMed1989

Surgical management of aortopulmonary septal defect.

Fourteen patients with malseptation of the aortopulmonary trunk underwent operative repair from 1978 to 1988. Age ranged from 1 year to 35 years (mean age, 9.6 years). Five patients had type I, 6 had type II, and 3 had type III lesions. The hemodynamic disturbance in all patients was the consequence of a large left-to-right shunt (mean pulmonary/systemic flow ratio, 2.38:1) with increased pulmonary vascular resistance (mean value, 4.47 units/m2). Our initial surgical experience with closure under cardiopulmonary bypass through the transaortic route in 3 patients and the transpulmonary approach in two patients resulted in 3 deaths. In the 9 subsequent patients, division and repair of the defect in the great vessels yielded uniformly good results. During follow-up, which ranged from 3 months to 2 years, all 11 survivors had good clinical improvement and none showed residual defects on restudy. Pulmonary artery pressure and pulmonary vascular resistance decreased in all patients except 1.

Adult↗
PubMed1989

A geochemical basis for endomyocardial fibrosis.

Analysis of hearts of patients dying from endomyocardial fibrosis showed a significantly greater concentration of cerium, a lanthanide present in leafy vegetables and root tubers, than in control hearts. This may be important in the pathogenesis of the disease and provides a geographical basis for the prevalence of the disease in the tropics.

Cerium↗
PubMed1989

Clinical course of endomyocardial fibrosis.

The survival pattern, morbidity, and clinical course of 145 patients with endomyocardial fibrosis who were followed up between November 1975 and June 1987 were studied. The diagnosis was confirmed in all cases by cardiac angiography, or echocardiography, or necropsy. Percentage survival at the end of one and 9.5 years was 76.11 and 26.35 respectively. History, physical examination, electrocardiography, and cardiac catheterisation were studied at the first presentation. The determinants of early mortality were studied by univariate Kaplan-Meier estimates compared by the log rank test and Cox proportional hazards multiple regression analysis. Significant univariate predictors of early mortality were QRS axis above +90 degrees, intraventricular conduction delay (QRS duration greater than 0.12 s), duration of symptoms before presentation, New York Heart Association functional classes III and IV, presence of embolic episodes, right atrial mean pressures greater than 20 mm Hg, right ventricular end diastolic pressure greater than 20 mm Hg, and aortic oxygen saturation less than 85%. The significant multivariate predictors of mortality were cyanosis, New York Heart Association functional class at first presentation, and right atrial mean pressure greater than 20 mm Hg. The bleak prognosis of endomyocardial fibrosis did not substantially improve despite advances in the medical management of congestive cardiac failure during the period of the study.

Adult↗
PubMed1988

Unusual manifestation of valvular vegetations.

Mitral obstruction due to a large vegetation of bacterial endocarditis occurred in a 30 year old man. 2-D echocardiogram revealed an echodense mass obstructing the mitral valve. The patient was successfully treated by mitral valve replacement.

Adult↗
PubMed1987

Surgical treatment of endomyocardial fibrosis.

Forty-six patients with endomyocardial fibrosis underwent endocardiectomy and replacement of tricuspid, mitral, or both atrioventricular valves between April, 1981, and October, 1984, at the Sree Chitra Tirunal Institute, Kerala State, India, which has a high incidence of the disease. Six patients were in New York Heart Association Functional Class III and 40 patients in Class IV. The operative mortality within 30 days of the procedure and late mortality during the first two years postoperation were 21.7% and 13%, respectively. Age under 15 years was a significant correlate of operative mortality (p = .05). Non-fatal thromboembolic episodes occurred in 6 patients during the two years of postoperative observation. The life table estimate of survival inclusive of operative mortality at two years was 67%. Despite high operative mortality, endocardiectomy with atrioventricular valve replacement is advisable for functionally disabled patients with endomyocardial fibrosis whose prognosis otherwise is dismal.

Adolescent↗
PubMed1986

A geochemical basis for endomyocardial fibrosis.

In a search for geochemical factors that could play a role in the pathogenesis of tropical endomyocardial fibrosis, endomyocardial tissue samples obtained from patients at necropsy or operation were analysed for major elements present in laterite and monazite, which are important soil constituents of Kerala State of India. Atomic absorption spectrophotometry was used for detecting iron, silicon, aluminium, zinc, magnesium, calcium, sodium, potassium, and manganese and neutron activation analysis for thorium. Compared with control samples from victims of fatal accidents, an excess of thorium, sodium, and calcium and a deficiency of magnesium were present in samples from patients. It has been shown earlier that the staple diets of people in Kerala have high concentrations of thorium, and these data show that thorium can become concentrated in cardiac tissues. It is speculated that thorium excess in conjunction with magnesium deficiency may play a role in the causation of tropical endomyocardial fibrosis.

Endomyocardial Fibrosis↗
PubMed1986

Postoperative evaluation of endomyocardial fibrosis.

25 patients with angiographic features suggestive of endomyocardial fibrosis underwent endocardiectomy and atrioventricular valve replacement. There were 8 deaths. 17 survivors were reevaluated after a mean follow-up of 13.5 months. 8 had right ventricular endomyocardial fibrosis (RVEMF) 5 had left ventricular endomyocardial fibrosis (LVEMF) and 4 had biventricular disease (BVEMF). The survivors showed a significant improvement in their clinical features and functional status. There was a significant reduction in atrial size in X-ray. Hemodynamic data showed a significant fall in right heart filling pressure, right ventricular systolic pressure and pulmonary artery mean pressure, and a significant fall in left heart filling pressure in patients with left ventricular disease either alone or as a part of biventricular disease. In ventriculogram, while there was no change in right ventricular shape after endocardiectomy, left ventricular shape was restored to near normal. The significant improvement is mostly due to the correction of the regurgitant lesion and to some extent due to restoration of ventricular compliance.

Adolescent↗
PubMed1983

Surgical palliation for endomyocardial fibrosis: early results.

Endomyocardial fibrosis is a fatal disease of obscure aetiology which is notably prevalent in Uganda, Brazil, Kerala State in India, and certain other parts of the world. The main disability in the disease results from fibrotic obliteration of ventricular chambers and insufficiency of the mitral and tricuspid valves. The poor response to medical treatment and the bleak prognosis of the patients led to the introduction of endocardiectomy and replacement of the atrioventricular valves as a palliative procedure by Dubost and colleagues. The present report on the early results in 17 patients from Kerala State would support the continued use of this palliative procedure in endomyocardial fibrosis with severe disability.

Adolescent↗
PubMed1983

Early angiographic features of right ventricular endomyocardial fibrosis.

Right ventricular (RV) angiograms were done in 45 patients with left ventricular (LV) endomyocardial fibrosis (EMF). 34 patients had angiographic features compatible with the diagnosis of RV and LV EMF. 11 patients showed the angiographic features of EMF on the left side, but did not show the classical angiographic features on the right side. The RV angiograms of these 11 patients showed a disturbance of the normal parenchymal pattern along the septal margin, irregular small filling defects near the apex and the septal region and minimal tricuspid regurgitation. Biopsies from the RV taken from 2 of these patients during operation for mitral valve replacement had histological features compatible with the diagnosis of EMF on the right side also. This study demonstrates that the early angiographic features of RV EMF differ from those of well-established cases already described in the literature, and that it is possible to spot RV EMF well before the conventional features appear in RV angiograms.

Adult↗