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Biomedical subjects

M C Yu

Publications and source records attributed to M C Yu.

At least 199 records · Page 11Linked to original sources
PubMed1982

Hepatitis B virus and cigarette smoking: risk factors for hepatocellular carcinoma in Hong Kong.

One hundred seven Chinese patients with primary hepatocellular carcinoma (PHC) were compared with 107 hospital controls for the presence of hepatitis B surface antigen and smoking, drinking, and dietary habits. Eighty-two % of PHC cases were hepatitis B surface antigen positive compared to 18% of controls (relative risk, 21.3; 95% confidence limits, 10.1 and 45.9). Prior history of jaundice was significantly related to PHC, independent of hepatitis B surface antigen status. There was a significant association between cigarette smoking and PHC negative for hepatitis B surface antigen. The relative risk of hepatitis B surface antigen-negative PHC for heavy smokers (20 + cigarettes/day) was 3.3 compared to light smokers and nonsmokers (95% confidence limits, 1.0 and 13.4). Our data indicated that infection by the hepatitis B virus and cigarette smoking were independent risk factors for PHC.

Carcinoma, Hepatocellular↗
PubMed1982

N-Nitroso compounds and childhood brain tumors: a case-control study.

We questioned mothers of 209 young brain tumor patients and mothers of 209 controls about experiences of possible etiological relevance which they had during pregnancy or which their children had while growing up. Long-suspected brain tumor risk factors such as head trauma and X-rays appeared to be factors for relatively few cases. Increased risk was associated with maternal contact with nitrosamine-containing substances such as burning incense (odds ratio, 3.3; p = 0.005), sidestream cigarette smoke (odds ratio, 1.5; p = 0.03), and face makeup (odds ratio, 1.6; p = 0.02); with maternal use of diuretics (odds ratio, 2.0; p = 0.03) and antihistamines (odds ratio, 3.4; p = 0.002); and with the level of maternal consumption of cured meats (p = 0.008). These drugs contain nitrosatable amines and amides, and the cured meats contain nitrites, chemicals which are precursors of N-nitroso compounds. We propose a hypothesis that brain tumors in these young people are related to in utero exposure to N-nitroso compounds and their precursors, the most potent nervous system carcinogens known in experimental animals.

Adolescent↗
PubMed1981

Brain tumors in children and occupational exposure of parents.

Ninety-two cases of brain tumor in children less than 10 years old were compared with 92 matched controls for parental occupational history. Cases were more likely than controls to show material occupations involving chemical exposure, paternal occupations involving solvents, and employment of father in the aircraft industry. These three factors were not affected by adjustment for the potential confounding variables examined in this study.

Air Pollutants↗
PubMed1981

Elevated levels of prolactin in nulliparous women.

Follicular-phase (Day 11) plasma prolactin, and plasma and urinary oestrogen levels of 70 nulliparous nuns were compared with those of 80 of their sisters, of whom 62 were parous. The nuns and their nulliparous sisters did not differ significantly in their prolactin and oestrogen levels. No differences in plasma oestrogens or urinary oestriol ratio were found between the parous and the nulliparous women. However, the mean prolactin level of the nuns and their nulliparous sisters was 35% higher than that of the parous women in the sample taken approximately 1 3/4 h after rising (p less than 0.0005), and 24% higher (P less then 0.01) in the 2nd sample taken 2 h later. The elevation was independent of age, weight, and age at menarché. Age at first full-term pregnancy, at least up to the age of 30, and second or subsequent full-term pregnancies had no further effect on prolactin level. This study suggests that the effect of early first full-term pregnancy in lowering breast cancer risk may be mediated, at least in part, by permanently lowering the level of circulating prolactin.

Adult↗
PubMed1979

Risk factors for cancer of the testis in young men.

An individual matched case-control study of testis cancer in 131 men under age 40 was conducted to investigate antecedent risk factors including events during prenatal life. Ten patients were born with an undescended testis compared to only two controls (p less equal to 0.02), a previously reported risk factor. Two new risk factors were uncovered: six patients-mothers received hormones during the index pregnancy compared to only one control-mother, and eight patient-mothers and two control-mothers reported excessive nausea as a complication of the index pregnancy. A hypothesis linking these three factors is presented: viz, that a major risk factor for testis cancer is a relative excess of certain hormones (in particular estrogen) at the time of differentiation of the testes.

Adolescent↗