Biomedical subjects
Publications and source records attributed to E Sumithran.
The association between hepatitis B virus infection and primary hepatocellular carcinoma is reviewed. On the basis of serological and tissue examination there is a close link between virus infection and the tumour. While there is evidence to favour an oncogenic role for virus this is not conclusive, and other possible explanations for the relationship are discussed.
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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.
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.
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.
Thirty-nine infants suspected of having cow's milk protein intolerance (C.M.P.I.) were investigated, and jejunal biopsies were performed before and after challenge with cow's milk. Thirty patients had significant jejunal mucosal damage after milk challenge, but symptoms of diarrhoea and vomiting developed in only twenty-two. The patients with symptoms were subsequently managed on a diet free from cow's milk until tolerance developed. However, the eight infants without symptoms (but with jejunal mucosal damage) made satisfactory clinical progress, with adequate weight-gain, on a diet of cow's milk. Repeat jejunal biopsy specimens from two of these patients showed that there had been a definite improvement since the immediate post-challenge biopsy specimens were taken. Most patients with C.M.P.I. who need to be treated with a diet from which cow's milk has been eliminated may be detected by clinical means alone, and the remainder may continue on a cow's milk diet unless or until symptoms develop. There seems to be no clinical justification for routine jejunal biopsy in infants in whom C.M.P.I. is suspected.
Cancer of the cervix is exceedingly uncommon in the Malaysian Orang Asli (aborigine), despite the presence of factors associated with an increased risk of developing this malignancy. In only three patients was the diagnosis of carcinoma of the cervix established, out of a total of nearly 18,000 female inpatients, admitted to the Gombak Orang Asli Hospital over a 13-year period. Over this same period, 81 female patients were diagnosed as having cancer. Interviews with female Orang Asli patients show the presence of alleged risk factors for cervical cancer, including early age of first intercourse, multiparity and non-circumcision of husbands. The low incidence of cancer of the cervix in this aborigine community may be due to the strict moral code of the Orang Asli, limiting extramarital sexual activity and associated venereal infection.
Necropsy and clinical data show that primary hepatocellular carcinoma (PHC) is the commonest cancer among the Senoi (a Malaysian aboringine group). The other aboringine tribes do not appear to have this high predilection for liver cancer. In the necropsy series, PHS was present in 10 out of 22 Senoi patients with cirrhosis. All the 22 livers contained hepatocytes that stained with Shikata's orcein stain and specific immunoperoxidase and immunofluorescent stains for hepatitis B antigen (HBAg). This observation raises the strong possibility that hepatitis B may be an important etiologic factor in the development of cirrhosis and PHC in the Senoi. The reason for the high susceptibility of the Senoi for HB virus infection is not clear, and the role of aflatoxin in the pathogenesis of PHC in the Senoi has yet to be determined. That the Senoi are a numerically small community, maintaining their own unique dietary and social customs and living in readily accessible areas in the Malaysian jungle, makes them an ideal population for the study of factors in the etiology of liver cancer.
Methods for the localisation of hepatitis B surface antigen (HBsAg) in paraffin sections of the liver include the detection of ground-glass hepatocytes and the use of Shikata's orcein stain, and of immunoperoxidase and immunofluorescent techniques. A comparative study of the different methods on 20 livers shows the orcein stain to be the method of choice for routine use. The Shikata stain is not only specific but is relatively inexpensive, easily performed, and stains out distinct cytoplasmic inclusions even in stored formalin-fixed livers, old paraffin blocks, and autolysed livers. Since HBsAg is irregularly distributed in the liver, adequate sampling is necessary to prevent false negative; when sufficient tissue is available at least five blocks should be examined before a case is labelled as HBsAg-negative.
Necropsies were performed on 285 consecutively unclaimed Orang Asli bodies from Gombak Orang Asli Hospital during an eight-year period from May 1967 to April 1975. Of the 25 malignant neoplasms, hepatocellular carcinoma was by far the commonest (36%). The nine patients with this neoplasm had coexistant macronodular cirrhosis. There were 20 cases of cirrhosis; 45% of these had coexistant hepatocellular carcinoma. The 53,000 Orang Aslis living in West Malaysia comprise three tribes, the Negrito, Senoi, and Melayu Asli (Proto Malays). The Sinoi appear to have a high predilection for liver cancer, all our nine cases occurring in this group. These aboriginal people live in the jungles where they practice shifting cultivation and maintain their own dietary and social customs. Detailed studies of their dietary habits may provide a clue to the etiology of liver cancer in these people.
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Explore the source record for details and available documents.