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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.