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Biomedical subjects

M C Yu

Publications and source records attributed to M C Yu.

At least 181 records · Page 10Linked to original sources
PubMed1986

Cigarette smoking, obesity, diuretic use, and coffee consumption as risk factors for renal cell carcinoma.

One hundred sixty incident cases of renal cell carcinoma under the age of 55 years and an equal number of age-(within 5 yr), race-, and sex-matched neighborhood controls were interviewed. Cigarette smoking was a risk factor for renal cell carcinoma in males [relative risk (RR) = 2.1, one-sided P = .02] but not in females (RR = 1.1, P = .50). Obesity was a significant risk factor in both males and females: The RR for a 4th quartile compared to a 1st quartile Quetelet's Index 10 years ago was 2.5 for males and 3.3 for females. Additional risk factors in females were diuretic use (RR = 4.5, P = .002) and daily coffee consumption (RR = 2.3, P = .06).

Adult↗
PubMed1986

Cantonese-style salted fish as a cause of nasopharyngeal carcinoma: report of a case-control study in Hong Kong.

Two hundred fifty incident cases of nasopharyngeal carcinoma under age 35 years in Hong Kong Chinese and an equal number of age- and sex-matched friend controls were interviewed. Mothers of cases and controls were interviewed also, if available, to obtain information on childhood events concerning the study subjects. Consumption of Cantonese-style salted fish during all time periods was significantly associated with nasopharyngeal carcinoma; the association was especially strong during childhood. The relative risk for having Cantonese-style salted fish as one of the first solid foods during weaning was 7.5 (95% confidence limits, 3.9, 14.8), and the relative risk for consuming the food at least once a week compared to less than once a month at age 10 years was 37.7 (95% confidence limits, 14.1, 100.4). It is estimated that over 90% of young nasopharyngeal carcinoma cases in Hong Kong Chinese can be attributed to consumption of this food during childhood.

Adult↗
PubMed1985

Pancreas cancer is unrelated to the workplace in Los Angeles.

From 1975 to 1981, 490 cases of exocrine adenocarcinoma of the pancreas, representative of those occurring in the working-age population of Los Angeles County, were compared to matched neighborhood controls. Among the items of information obtained from each subject was a lifetime job history and a history of specific workplace exposures; this came directly from both case and control in 124 pairs. Although the matched cases and controls were generally comparable, they were not matched with respect to job history. While other strong risk factors for pancreas cancer were found in the same study, no significant or suggestive differences in the jobs or perceived chemical or process exposures between cases and controls were found. Those minor differences which were found did not suggest credible mechanisms of carcinogenesis when examined in detail. Our study does not point to the workplace as an important determinant of pancreas cancer in the economically diversified urban area of Los Angeles.

Adenocarcinoma↗
PubMed1985

A serological case-control study of primary hepatocellular carcinoma in Guangxi, China.

Guangxi is a very high-risk area for primary hepatocellular carcinoma (PHC); the age-standardized (world population) rates for males and females in that Chinese Autonomous Region were 32.5 and 8.5, respectively. Blood specimens from 50 PHC patients and 50 age- and sex-matched controls in Guangxi were analyzed for hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen. Eighty-six % of cases were hepatitis B surface antigen positive, compared to 22% of controls (relative risk, 17.0). We estimate from the data that persistent hepatitis B virus infection can account for at least 80% of all PHC cases occurring in Guangxi. The consistency of our findings with those from Hong Kong and Taiwan strongly suggests that hepatitis B virus infection is also an important risk factor for PHC in other parts of southern China.

Adolescent↗
PubMed1985

Epidemiology of nasopharyngeal carcinoma in Malaysia and Hong Kong.

We conducted 2 case-control studies with Malaysian and Hong Kong Chinese and investigated the association between salted fish intake and nasopharyngeal carcinoma (NPC). Both studies show a highly significant association between salted fish intake, especially during childhood, and NPC. Furthermore, from our results we estimate that the majority of NPC cases occurring in the southern Chinese can be attributed to their consumption of this food early in life.

Adult↗
PubMed1985

Attempts to isolate N-nitroso compounds from Chinese-style salted fish.

Various types of salted fish have been collected from Hong Kong and analyzed for volatile nitrosamines and bacterial mutagenicity. Both of these parameters were low in the samples as collected. Exposure of these samples to nitrite yields substantial quantities of nitrosamines and mutagenic activity.

Animals↗
PubMed1985

Risk factors for breast cancer in Tianjin, People's Republic of China.

Four hundred fifteen patients with breast cancer who were between 25 and 59 years old were interviewed. They were identified through a breast cancer screening program conducted by the Tianjin Cancer Institute during 1977-80. Controls were women who participated in the screening program but were free of breast cancer. The study confirmed early menarche, late age at first birth, and late menopause as major risk factors for breast cancer. Total duration of lactation was significantly associated with a reduction in its risk among parous women, but this was explained by higher parity among controls. No significant differences were observed between patients and controls in the amount of exposure to chest radiographs or use of hormones.

Adolescent↗
PubMed1985

Some epidemiologic observations of nasopharyngeal carcinoma in Guangdong, People's Republic of China.

Chinese in the province of Guangdong have the highest risk of nasopharyngeal carcinoma (NPC) in China. Within Guangdong, variation in rates among the 3 major dialect groups is threefold. The Cantonese who reside in the central region of Guangdong display the highest risk of NPC. Among the Cantonese, those living on boats have twice the risk of those who live on land. These observations are consistent with earlier studies of southern Chinese residing in Hong Kong and Southeast Asia.

China↗
PubMed1985

Smoking and other risk factors for lung cancer in women.

A case-control study among white women in Los Angeles County was conducted to investigate the role of smoking and other factors in the etiology of lung cancer in women. A total of 149 patients with adenocarcinoma (ADC) and 71 patients with squamous cell carcinoma (SCC) of the lung and their age- and sex-matched controls were interviewed. Personal cigarette smoking accounted for almost all of SCC and about half of ADC in this study population. Among nonsmokers, slightly elevated relative risk(s) (RR) for ADC were observed for passive smoke exposure from spouse(s) [RR = 1.2; 95% confidence interval (Cl) = 0.5, 3.3] and at work (RR = 1.3; 95% Cl = 0.5, 3.3). Childhood pneumonia (RR = 2.7; 95% Cl = 1.1, 6.7) and childhood exposure to coal burning (RR = 2.3; 95% Cl = 1.0, 5.5) were additional risk factors for ADC. For both ADC and SCC, increased risks were associated with decreased intake of beta-carotene foods but not for total preformed vitamin A foods and vitamin supplements.

Adenocarcinoma↗
PubMed1983

Effects of maternal hyperphenylalaninemia on fetal brain development: a biochemical study.

We examined the effects of maternal hyperphenylalaninemia on body and brain growth, and the biochemical maturation of the fetal and neonatal rat brain. Elevated concentrations of plasma phenylalanine were induced in pregnant rats under two experimental conditions from the 14th through the 21st days of gestation. In the first treatment, pregnant rats were injected subcutaneously with alpha-methylphenylalanine (to inhibit maternal liver phenylalanine hydroxylase) at a dosage of 30 mg/100 g body weight plus phenylalanine supplementation (to increase maternal and fetal plasma phenylalanine) at a dosage of 60 mg/100 g body weight two times daily. In the second treatment, pregnant dams were injected with phenylalanine only at a dosage of 65 mg/100 g body weight three times daily. Treatment with alpha-methylphenylalanine/phenylalanine (mPhe/Phe) resulted in a 76% inhibition in the activity of maternal phenylalanine hydroxylase and a 25-fold increase in the mean daily concentration of phenylalanine in the maternal and fetal plasma. Phenylalanine treatment alone resulted in a 15-fold increase in plasma phenylalanine in the maternal and fetal animals. Significant reductions in body and brain weights in the fetal and neonatal rats were found in both treatment groups. Biochemical determinations indicated that the total DNA, RNA, and protein contents of the cerebra were reduced, with the reductions being greater in the mPhe/Phe- than the phenylalanine-treated rats. However, the retardation in body and brain growth of both treatment groups did not appear to be permanent because substantial recovery was noted in the rats after postnatal day 7. These results suggest that exposure of the fetus to high plasma concentrations of phenylalanine caused a delay in the biochemical maturation of the fetal rat brain.

Animals↗
PubMed1983

Effects of maternal hyperphenylalaninemia on fetal brain development: a morphological study.

We examined the effects of maternal hyperphenylalaninemia on the morphological development of the fetal and neonatal rat brain. High concentrations of phenylalanine were induced in pregnant rats from embryonic days 14 through 21 by subcutaneous injections of alpha-methylphenylalanine (mPhe) (to inhibit maternal phenylalanine hydroxylase) at a dosage of 30 mg/100 g body weight plus phenylalanine (Phe) supplementation (to raise fetal plasma phenylalanine) at a dosage of 60 mg/100 g body weight two times daily at 12-h intervals. This treatment resulted in a significant hyperphenylalaninemia compared with vehicle-injected, pair-fed control rats. At embryonic day 21, mPhe/Phe-treated embryos displayed a reduced thickness of the cortical plate and marginal zone, a decrease in the size of postmitotic neurons, and an increase in the packing density of cells in the cortical plate. There was an increase in the number of pyknotic cells (cell death) and in the reactive microglia in the mPhe/Phe-treated group. During the postnatal period the differences between mPhe/Phe-treated and control rats became fewer and by postnatal day 7 the morphology of the mPhe/Phe-exposed brains was similar to the controls. These morphologic data, in conjunction with our previous biochemical finding of reduced cerebral DNA, RNA, and protein contents of mPhe/Phe-treated rats, indicate that the induced hyperphenylalaninemia caused a significant delay in the development of the cerebral cortex which was able to undergo recovery during the postnatal period.

Animals↗
PubMed1983

Acceleration of the regeneration of the crushed hypoglossal nerve by testosterone.

The effect of testosterone propionate (TP) on regeneration of the crushed hypoglossal nerve was studied in young adult rats. The TP treatment promoted axonal outgrowth as measured by an increase in the proportion of hypoglossal neurons labeled by retrograde transport of horseradish peroxidase injected into the tongue at selected postlesion periods compared with that in controls. The result indicated that TP exerts its effect on regeneration primarily by increasing the metabolic activity in hormone target neurons. The somatotopic organization of the hypoglossal nucleus and its projection into the major nerve branches were unaltered subsequent to crush injury. The maintenance of specificity was attributed to the intact perineurial and endoneurial sheaths which guided regenerating fibers to their original targets.

Animals↗
PubMed1983

Hepatitis, alcohol consumption, cigarette smoking, and hepatocellular carcinoma in Los Angeles.

Seventy-eight black patients and white patients with primary hepatocellular carcinoma (PHC), 70 years or younger at diagnosis, and 78 age-, sex-, and race-matched neighborhood controls were interviewed. Information sought included usual dietary and drinking habits, cigarette smoking habits, prior medical conditions including a history of hepatitis, prior exposure to blood products, and occupational history. Cigarette smoking was a risk factor for PHC; the relative risk (RR) for current smokers of more than one pack/day compared to nonsmokers was 2.6. Alcohol consumption was also a significant risk factor for PHC; individuals who drank 80 g or more of ethanol per day had a RR of 4.2 compared to those drinking less than 10 g/day. In addition, a history of hepatitis (RR = 13.0) and a history of blood transfusions (RR = 7.0) were significant risk factors for PHC. Each of these factors remained significant after adjustment was made for the others.

Alcohol Drinking↗
PubMed1983

Risk factors for meningiomas in men in Los Angeles County.

A case-control study among men in Los Angeles County was conducted to investigate further the causes of intracranial meningiomas. Meningioma patients and a neighbor of each one were interviewed about past experiences that might be associated with tumor development. Analysis of information from the 105 matched pairs showed an association with meningioma occurrence for various factors relating to head trauma and head X-rays: 1) ever boxed as a sport [odds ratio (OR) = 2.0, P = 0.03], 2) had a serious head injury (OR = 1.9, P = 0.01), and 3) had X-ray treatment to the head before 20 years of age and/or had five or more full mouth dental X-ray series before 1945 (OR = 3.5, P = 0.02). Of the 105 subjects, 72 (69%) had a history of exposure to at least one of these factors.

Adult↗
PubMed1983

Salted fish and inhalants as risk factors for nasopharyngeal carcinoma in Malaysian Chinese.

We conducted a case-control study of nasopharyngeal carcinoma among Malaysian Chinese to test inhalants, salted fish consumption, and use of tobacco, alcohol, and nasal ointments as risk factors for the disease. Interviews with 100 cases and 100 controls indicated that salted fish consumption during childhood was a significant risk factor (relative risk, 3.0; p = 0.04); childhood daily consumption of this food item compared to nonconsumption carried a relative risk of 17.4 [95% confidence interval = (2.7, 111.1)]. Occupational exposure to smokes (relative risk, 6.0; p = 0.006) and to dusts (relative risk, 4.0; p less than 0.001) was also significantly associated with nasopharyngeal carcinoma. The two risk factors (consumption of salted fish and exposure to smoke and/or dust) were independent of each other. There was no association between nasopharyngeal carcinoma and tobacco, alcohol, or nasal ointments.

Administration, Intranasal↗