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Biomedical subjects

E Sumithran

Publications and source records attributed to E Sumithran.

At least 19 recordsLinked to original sources

Concomitant mucinous tumors of appendix and ovary. Result of a neoplastic field change?

BACKGROUND: Mucinous tumors of the appendix and ovary are known to occur together in association with pseudomyxoma peritonei. It has been postulated that this association may be attributable to the development of independent tumors or to metastasis from one site to another. METHODS AND RESULTS: This article reports two patients with concomitant mucinous ovarian and appendiceal tumors in the absence of pseudomyxoma peritonei. CONCLUSIONS: The evidence suggests that these tumors are independent primary neoplasms that develop as a result of neoplastic field change that affects colonic-type epithelium.

Appendiceal Neoplasms

Pharmacologic nephrectomy with chronic angiotensin converting enzyme inhibitor treatment in renovascular hypertension in the rat.

Angiotensin converting enzyme (ACE) inhibitor treatment in renovascular hypertension is associated with acute compromise of renal function in patients with bilateral renal artery stenosis or with arterial stenosis to a single functioning kidney. Recent evidence has suggested that renal function is also compromised in the stenosed kidney of patients with unilateral renal artery stenosis. The long-term consequence of this reduction in renal function is not known. We have studied the effect of chronic ACE inhibition with enalapril on renal structure and function in rats with the two-kidney one-clip model of renovascular hypertension. Four weeks after placement of a clip on the left renal artery, hypertensive rats were randomized to treatment with enalapril, minoxidil, or to a no treatment group. Twelve months later split kidney function was determined by chromium 51-labeled ethylenediamine-tetraacetic acid clearance in surviving rats. Clearance of the clipped kidney was 0.0 ml/min (enalapril group), 0.26 +/- 0.23 ml/min (minoxidil group), and 0.74 +/- 0.13 ml/min (untreated group). The clipped kidney from the enalapril treated rats weighed much less than the minoxidil group or the untreated group (0.46 +/- 0.1 gm, 1.2 +/- 0.07 gm, and 1.14 +/- 0.10 gm, respectively). Enalapril treatment was stopped for 2 weeks in five rats. The clipped kidney remained small and nonfunctional. Histologic examination revealed marked interstitial fibrosis and tubular atrophy of the clipped kidneys from the enalapril treated group in contrast to minor changes in the minoxidil treated and untreated groups. After 12 months of treatment, survival in the enalapril group was 84%, 48% in the minoxidil group, and 15% in the untreated group.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors

Cardiac 3,4-dihydroxyphenylethylene glycol (DHPG) and catecholamine levels during perindopril therapy of chronic left ventricular failure in rats.

1. Left ventricular myocardial infarction was induced in female Wistar rats by ligation of the left anterior descending coronary artery. 2. One month following operation, rats with infarcts developed marked cardiomegaly compared to sham operated rats, indicating the presence of chronic left ventricular failure. 3. The ratio of the noradrenaline metabolite 3,4-dihydroxyphenylethylene glycol (DHPG) to noradrenaline (NA) was elevated in the right ventricle of rats with heart failure one month following infarction, suggesting a chronic increase in cardiac sympathetic activity. 4. Perindopril therapy for one month commenced 4 weeks after infarction returned cardiac weights to normal and significantly reduced right ventricular DHPG/NA ratios. 5. The results suggest that ACE inhibition with perindopril reduces elevated levels of cardiac sympathetic activity in rats with chronic left ventricular failure and leads to regression of cardiomegaly.

Angiotensin-Converting Enzyme Inhibitors

An assessment of the value of frozen sections in gynecological surgery.

In 203 consecutive gynecological operations where frozen sections were performed, 35.6% were from conditions of the ovary, 22.7% from the cervix, 18.2% from the endometrium, and 11.4% from the vulva. There were 0.5% false-positive, 1.0% false-negative and 2.0% deferred diagnosis. Incorrect interpretation was the cause of the single false-positive diagnosis, while the false-negative diagnoses were due to errors in block selection. The deferred diagnoses mainly occurred in gynecological conditions where diagnosis was difficult, required extensive sampling or a formal mitotic count. As in other surgical fields, gynecological frozen sections were used principally to guide the extent of surgery. The most valuable frozen sections were in those instances where the operation was affected most. These were on lymph nodes in cases of carcinoma of the vulva and cervix, myometrial lesions in young women where myomectomy was being considered, and ovarian tumours to distinguish primary from secondary tumours. Occasionally, frozen sections were also found useful to establish margins of vulval and cervical tumours, in hysterectomy specimens of endometrial carcinomas to determine prognostic factors, and in suspected recurrences and metastases of tumours to determine the adequacy of the biopsy material. Frozen sections in obviously benign conditions, e.g., ovarian cysts without papillary or solid areas, were found to be unnecessary. Frozen sections are contraindicated when only a small amount of crucial material is available, as the paraffin diagnosis may be compromised. Pathologists should have a clear idea of the role of frozen sections in gynecological surgery and work closely with the surgeon in the management of gynecological oncology patients.

Fallopian Tube Diseases

Morphologic differences in the pattern of liver infiltration between systemic AL and AA amyloidosis.

Biopsy and necropsy tissue from 31 unselected patients with systemic amyloidosis, in which there was histologic evidence of liver involvement, were reviewed with reference to the location and pattern of amyloid deposition in the liver. Amyloidosis was classified into AA and AL types on the basis of immunohistochemistry and permanganate reaction of the amyloid deposits. Nineteen were categorized as AA (secondary) and 12 as AL (primary) amyloidosis. Deposition of AA amyloid was limited to the walls of vessels in the portal tract, constituting a "vascular" pattern. In AL amyloidosis, the deposits exhibited a "sinusoidal" pattern in that they were seen along hepatic sinusoids as well as in vessel walls. This difference was statistically significant (P less than .001). The histologic pattern of liver infiltration offers a valuable clue in the classification of systemic amyloidosis and provides information that may be useful in the selection of patients for therapy.

Amyloid

The prognostic significance of grading in borderline mucinous tumors of the ovary.

Fifty-three stage I borderline mucinous tumors of the ovary were placed into four histologic grades according to a simple system of grading based on degree of cell layering, nuclear characteristics, and mitotic count. Three patients died of recurrence and spread of their tumors. All three patients had grade 4 tumors, suggesting that there may be some prognostic value in grading borderline mucinous ovarian tumors.

Adenocarcinoma, Mucinous

Atrial natriuretic peptide and total exchangeable body sodium: relationships in rats with chronic myocardial infarction.

1. The relationship between plasma atrial natriuretic peptide (ANP) and body sodium was determined in rats 1 month after myocardial infarction induced by coronary artery ligation. After operation rats received a normal or a low salt diet, and total exchangeable body sodium was measured sequentially. 2. Rats with infarction receiving a normal salt intake did not retain sodium when compared with sham-operated controls. Rats receiving a low salt diet had a 10% decrease in body sodium (P less than 0.01). The decrease was the same in rats with infarction as in controls. 3. Plasma ANP was similar in control rats irrespective of salt status. Plasma ANP levels were markedly elevated in rats with infarction irrespective of salt status (P less than 0.01). 4. The rise in plasma ANP was correlated with cardiac hypertrophy and infarct size in animals fed both normal and low salt diets. However, there was no relationship between plasma ANP and exchangeable body sodium. 5. These results suggest that in this model of heart failure plasma ANP is raised by increased left atrial stretch in proportion to the severity of left ventricular dysfunction. In contrast, plasma ANP concentrations do not appear to be elevated as a consequence of increased right atrial pressure caused by sodium retention and expanded extracellular volume.

Animals

Chronic angiotensin converting enzyme inhibition in the two-kidney, one clip hypertensive rat.

Treatment with an angiotensin converting enzyme (ACE) inhibitor in renovascular hypertension produces acute effects on renal function; however, the long-term consequences of this are not known. We have studied the effect of chronic enalapril treatment on renal structure and function in the two-kidney, one clip model of renovascular hypertension in the rat. Four weeks after the left renal artery was clipped, the hypertensive rats were randomly allocated to treatment with enalapril, minoxidil or to no treatment. The drug dose was titrated for maximal hypotensive effect. After 4 months of treatment blood pressures were 129 +/- 3 mmHg (enalapril), 193 +/- 5 mmHg (minoxidil) and 220 +/- 4.8 mmHg (no treatment). Twelve months later survival was 84% (enalapril group), 48% (minoxidil group) and 15% (untreated group). Split kidney function (51Cr-EDTA clearance, ml/min) of the clipped kidneys was 0.0 (enalapril group), 0.26 +/- 0.23 (minoxidil group) and 0.74 +/- 0.13 (untreated group). The clipped kidney from enalapril-treated rats weighed 0.46 +/- 0.1 g, much less than in the minoxidil-treated group (1.2 +/- 0.07) or the untreated group (1.14 +/- 0.10). Enalapril treatment was withdrawn for 2 weeks in five rats, but the clipped kidney remained small and non-functional. Histological examination revealed marked interstitial fibrosis and tubular atrophy in clipped kidneys from both enalapril groups, in contrast to minor changes in the minoxidil-treated and the untreated groups. We conclude that chronic enalapril treatment of two-kidney, one clip hypertension in the rat improved survival and preserved total renal function, but was associated with irreversible fibrotic atrophy of the clipped kidney.

Angiotensin-Converting Enzyme Inhibitors

Cardiac hypertrophy and salt status in chronic myocardial infarction in the rat: effects of enalapril versus salt restriction.

The effects of salt restriction and the ACE inhibitor enalapril were compared in a model of chronic myocardial infarction in the rat. Total exchangeable sodium was measured by an isotopic dilution technique to quantitate the effects of the low salt diet and ACE inhibitor on body sodium and extracellular fluid. Rats with infarction developed a marked increase in cardiac weight (4.29 +/- 0.18 mg/g body weight) compared with control rats (3.64 +/- 0.08 mg/g, p less than 0.01). There was hypertrophy of both left and right ventricles. Salt restricted rats with infarction developed identical cardiomegaly (4.30 +/- 0.11 mg/g), although total exchangeable body sodium fell by 10% (p less than 0.001). In contrast, rats with infarction receiving enalapril developed significantly less cardiomegaly (3.97 +/- 0.10 mg/g) while body sodium remained unchanged. Rats with infarction had a significant increase in lung weight which was not changed by salt restriction but which was abolished by enalapril. These results suggest that salt restriction does not prevent the progression of cardiomegaly in chronic left heart failure. In contrast our results confirm the ability of ACE inhibitors to prevent progressive cardiomegaly and left heart failure without affecting long-term changes in sodium balance.

Animals

Neurohumoral responses to chronic myocardial infarction in rats.

In chronic cardiac failure, various neurohumoral mechanisms are activated to sustain blood volume, blood pressure, and organ perfusion. Using the coronary artery ligation model of heart failure in the rat, we have measured changes in vasoactive hormone secretion and related these changes to salt and water status during a 1-month period. When compared with controls, rats with infarction had a marked rise in plasma atrial natriuretic peptide (294 +/- 59 vs. 79 +/- 10 pg/ml, p less than 0.001) although there was no increase in total exchangeable body sodium. Plasma renin activity and plasma aldosterone concentrations were the same for both rats with infarction and controls. Similarly, there were no significant differences in plasma arginine vasopressin, plasma osmolality, or plasma sodium concentration in rats with infarction. Ventricular norepinephrine levels were reduced in animals with infarction (p less than 0.01). Plasma atrial natriuretic peptide levels were raised in this model of chronic left ventricular failure. However, there was no salt retention and little stimulation of the renin-angiotensin-aldosterone system or vasopressin. The results suggest that high circulating atrial natriuretic peptide levels may prevent or limit salt and water retention, either directly or indirectly, by inhibiting the renin-angiotensin-aldosterone system.

Aldosterone

Atrial natriuretic peptide in chronic heart failure in the rat: a correlation with ventricular dysfunction.

To assess the relation between atrial natriuretic peptide and ventricular dysfunction, we simultaneously measured both atrial and plasma immunoreactive atrial natriuretic peptide concentrations in rats 4 weeks after myocardial infarction induced by left coronary artery ligation. When compared to controls (n = 39), rats with infarction (n = 16) had markedly elevated plasma immunoreactive atrial natriuretic peptide concentrations (1205.8 +/- 180.9 vs. 126.7 +/- 8.9 pg/ml, p less than 0.001) and reduced immunoreactive atrial natriuretic peptide concentrations in right and left atria (31.4 +/- 4.6 vs. 61.2 +/- 3.2 ng/mg, p less than 0.001; 14.9 +/- 2.2 vs. 32.7 +/- 2.4 ng/mg, p less than 0.001, respectively). Right ventricular weight increased in proportion to infarct size, and both were correlated with plasma immunoreactive atrial natriuretic peptide levels (r = 0.825, p less than 0.001 and r = 0.816, p less than 0.001, respectively). Right atrial immunoreactive atrial natriuretic peptide content was significantly higher than left in both controls and rats with infarction. Both right and left atrial immunoreactive atrial natriuretic peptide concentrations were negatively correlated with both right ventricular weight as well as plasma immunoreactive atrial natriuretic peptide concentrations (right atrium: r = -0.816, p less than 0.001, r = -0.708, p less than 0.01; left atrium: r = -0.687, p less than 0.01, r = -0.644, p less than 0.01, respectively). These results suggest that chronic stimulation of atrial natriuretic peptide release from both atria is associated with increased turnover and depleted stores of atrial natriuretic peptide in atria in proportion to the severity of heart failure. It also suggests that plasma atrial natriuretic peptide levels may be used as a reliable index of cardiac decompensation in chronic heart failure.

Animals

Race-related morphologic variations in hepatocellular carcinoma.

In West Malaysia, hepatocellular carcinoma (HCC) is common in the Chinese and in the members of the Senoi aboriginal tribe, two racial groups with diametrically opposite life-styles. Certain fundamental differences exist between the liver tumors in the two races. In the Senoi, the tumor occurs in a younger age group and there is a greater male preponderance than in the Chinese. There is also a very close relationship between hepatitis B virus infection, chronic active hepatitis, cirrhosis, liver cell dysplasia, and HCC in the Senoi and the tumors generally present as multiple nodules studding both lobes of the liver. In the Chinese, although a relationship between hepatitis B virus infection, HCC, and cirrhosis exists, this association is not as strong as in the Senoi and the tumors are generally large and solitary. The data suggest that, although the hepatitis B virus is probably an important oncogenic agent in both racial groups, there may be a difference in the pathogenesis of HCC in the two races.

Adult

Cows' milk protein-sensitive enteropathy: an important contributing cause of secondary sugar intolerance in young infants with acute infective enteritis.

The effect of cows' milk protein (CMP) on the mucosal disaccharidases was investigated in 23 infants with acute infective enteritis. Jejunal biopsies performed before and after cows' milk provocation were subjected to histological examination and to mucosal disaccharidase enzyme (lactase, sucrase, and maltase) analyses. After milk challenge, changes in mucosal histology were observed in 18 infants, in 17 of them the levels of all 3 mucosal disaccharidases were much reduced. 10 of these infants developed diarrhoea and, in 6, the stools were positive for reducing sugar. It is concluded that CMP has a deleterious effect on the jejunal mucosa of young infants recovering from infective enteritis, so that in the management of young infants with sugar intolerance secondary to infective enteritis, CMP and lactose should be excluded from the diet.

Acute Disease

Cows' milk protein-sensitive enteropathy. Combined clinical and histological criteria for diagnosis.

Cows' milk protein enteropathy is recognised as a significant cause of persistent diarrhoea and malabsorption in young infants, but there are as yet no generally accepted diagnostic criteria. A combined clinical and histological approach to the diagnosis of cows' milk protein-sensitive enteropathy has been used in 15 patients, and the following set of criteria are proposed. (1) Clinical disease (diarrhoea with or without vomiting) while receiving cows' milk protein. (2) Clinical improvement on a diet free of cows' milk protein. (3) Normal or mildly abnormal histology of jejunal mucosa when taken 6-8 weeks after symptoms subside. (4) Histological relapse, with or without clinical relapse, after re-exposure to cows' milk protein.

Animals

Cows' milk protein-sensitive enteropathy. An important factor in prolonging diarrhoea of acute infective enteritis in early infancy.

The possible role of cows' milk protein in prolonging diarrhoea in very young infants with acute infective enteritis was studied in 14 infants, 9 under the age of 2 months and 5 older than 6 months. Bacterial pathogens were isolated from the stools of 4 infants from the younger age group. After appropriate initial treatment the infants were maintained on a cows' milk protein-free formula. 6 weeks later jejunal biopsies were performed before and 24 hours after challenge with a low lactose cows' milk protein formula. The immunoglobulin and complement levels in the serum and duodenal juice were also estimated at these times. Attempts to isolate bacterial and viral pathogens in stools were again made in all patients. The 5 older infants clinically tolerated cows' milk protein and their pre- and postchallenge jejunal biopsies were within normal limits. However, significant histological changes were observed in the postchallenge jejunal biopsies of all 9 infants under 2 months of age. In addition, 5 of these infants developed diarrhoea. This suggests that the jejunal mucosa of very young infants previously fed a cows' milk protein-based formula and who contract infective enteritis suffers damage when rechallenged with cows' milk protein.

Animals