Induced abortions, contraceptive practices, and tobacco smoking as risk factors for ectopic pregnancy in Athens, Greece

A case-control study of the role of induced abortion and other factors on the subsequent occurrence of ectopic pregnancy was undertaken in 1986-1987 in Athens, Greece, where a similar study 20 years ago found a tenfold risk of ectopic pregnancy among women with one or more illegal induced abortions. Seventy women residents of Athens, consecutively admitted to the major state maternity hospital with a diagnosis of ectopic pregnancy, were individually matched with women with a newly diagnosed pregnancy of the same order as the ectopic index pregnancy. Two control women were found for each of 63 cases, but only one control for each of the remaining seven cases. All cases and controls were interviewed by the same qualified obstetrician. Statistical analysis was undertaken with stratification of individual matched triplets and pairs, as well as through conditional multiple regression procedures. The relative risk of recurrence of an ectopic pregnancy was 6.39 with 95% confidence interval (CI) 1.96-21.04. Miscarriages did not increase the risk of ectopic pregnancy. The relative risk for subsequent ectopic pregnancy among women with one or more induced abortion, compared to women without such abortions, was 1.87 (CI 0.84-4.16) controlling only for the matching factors, and 1.71 (CI 0.69-4.27) when marital status (a possible selection factor) was also accounted for in the conditional logistic regression. There was no evidence for increasing risk with increasing number of induced abortions. Past use of an intrauterine device (IUCD) was associated with a relative risk of 3.89 (0.72-21.02); the relative risk increased with the duration of use of the IUCD.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast size, handedness and breast cancer risk

Bra cup size and handedness were studied as possible risk factors for breast cancer. Data for 3918 cases and 11,712 controls from 7 centres were used to examine the association of handedness with laterality of breast cancer; data for 2325 cases and 7008 controls from 4 centres were used to assess the relation of bra cup size to breast cancer risk. There was a suggestive (P about 0.10) association of handedness with breast cancer laterality: odds ratio of a left-handed (or ambidextrous) woman having a left-sided cancer 1.22 (95% CI 0.96-1.56). Handedness may affect the lateral occurrence of breast cancer, although this tumour is in general more common in the left breast, possibly because this breast is usually slightly larger. Premenopausal women who do not wear bras had half the risk of breast cancer compared with bra users (P about 0.09), possibly because they are thinner and likely to have smaller breasts. Among bra users, larger cup size was associated with an increased risk of breast cancer (P about 0.026), although the association was found only among postmenopausal women and was accounted for, in part, by obesity. These data suggest that bra cup size (and conceivably mammary gland size) may be a risk factor for breast cancer.

Prevalence of cesarean section in Chang Gung Memorial Hospital, 1984-1989

This study was undertaken to estimate the cesarean delivery rate in Chang Gung Memorial Hospital (CGMH) and to determine whether the reasons for the rising rate have changed during the past 6 years. Since 1984, 43% of the rise in the cesarean rate was due to repeat cesareans, 29% due to dystocia, and 15% due to fetal distress. At the same time, the cesarean delivery rates due to abnormality of position and placentation dropped by 2% in either condition. The rate of cesarean delivery among those with a previous cesarean was 98%. In the future, if the number of vaginal deliveries after cesarean increases, then the overall cesarean delivery rate will decrease or stabilize.

Age at menarche, age at menopause, height and obesity as risk factors for breast cancer: associations and interactions in an international case-control study

The importance of age at menarche, age at menopause, height, and obesity as risk factors for breast cancer, and the possible interactions among these factors in breast cancer causation were investigated in a data set collected in the late 1960's, in an international multicenter case-control study. Multiple logistic regression procedures were used to model data from 3,993 breast cancer cases and 11,783 controls from 7 study centers representing the range of international variation of breast cancer incidence. Height and obesity (measured through the weight/height2 index) were independent risk factors for breast cancer among post-menopausal but not pre-menopausal women; post-menopausal women taller by 10 cm had a 12% higher risk of breast cancer (95% confidence interval, CI, 3-21%) and post-menopausal women of average height (say 158 cm) had an 11% higher risk of breast cancer (CI 7-16%) when they were heavier by 10 kg (and, therefore, more obese by 4 kg/m2). Age at menarche was a risk factor among both pre-menopausal and post-menopausal women, a delay of 2 years corresponding to a 10% reduction in breast cancer risk (CI 6-15%). Age at menopause was also a breast cancer risk factor, women with menopause at each 5 year age difference having a 17% higher risk of breast cancer (CI 11-22%). There is evidence of an interaction (deviation from the logistic regression-postulated multiplicativity) between obesity and age at menarche, implying that the protective effect of late menarche may not apply to overweight women or that late menarche may become detrimental in obese women. The estimated relative risk coefficients, when applied to average risk factor levels observed among control women, can explain only a small fraction of the difference in breast cancer incidence between Boston and Tokyo.

Prevalence of mottled enamel after 12 years of water fluoridation in Chung-hsing New Village

The prevalence of mottled enamel (dental fluorosis) was investigated among children, aged 6 to 15 years, in Chung-hsing New Village and in Tsao-tun Village. The drinking water in Chung-hsing New Village has been fluoridated for 12 years at a level of 0.6 ppm, while the drinking water in Tsao-tun contains a negligible level of 0.08 ppm. The degree of mottled enamel was assessed by using Dean's Index and the Community Fluorosis Index (CFI), the latter being derived from Dean's Index for the purpose of comparison. In Dean's Index, 6 classes based on the severity of the mottling, are identified: normal, questionable, very mild, mild, moderate, and severe. The results showed that children in Chung-hsing had whiter teeth than those in Tsao-tun Village. In the fluoridated group, 5.8% of children fell into the "very mild" mottling category, as compared to 0.9% in Taso-tun, the control area. For the "mild" class, the rate was 1.9% for Chung-hsing New Village and 0.4% for Tsao-tun. With only one exception in Tsao-tun, none of the children in the two groups showed mottling in the "moderate" or "severe" classes. The Community Fluorosis Index (CFI) was 0.15 for the Chung-hsing group, indicating that the occurrence of mottled enamel is very low when compared with data from fluoridation programs in other countries. It is concluded that in Taiwan, a 0.6 ppm fluoride concentration in drinking water, which has previously been reported to be effective in prevention of dental caries, is associated with only negligible mottling of enamel. Even when mottling does occur, the degree is very mild and only small chalky spots can be seen on the teeth.

Epidemiology of pancreas cancer (1988)

This article reviews the epidemiology of cancer of the pancreas, both descriptive and analytical, at all times cognizant of the problems of misdiagnosis, particularly underdiagnosis, of this lethal disease that continue to hinder epidemiological studies. Pancreas cancer is consistently reported to occur more frequently in men than in women, in blacks than in whites, and in urban rather than rural population groups. In some countries, the mortality rates continue to rise, whereas in others, declining levels of disease can be seen among members of younger birth cohorts. Although some of these patterns can be explained by variation in pancreas cancer risk factors, many cannot. Analytical studies consistently demonstrate that cigarette smoking increases the risk of cancer of the pancreas, and this appears, at the present time, to be the only clearly demonstrated risk factor for pancreatic cancer. Although the association with disease risk and coffee consumption, alcohol consumption, occupational exposures, diabetes, pancreatitis, and other factors requires clarification, it appears likely that the most fruitful research area in the coming years may involve exploration of pancreatic cancer risk and nutritional practices.

Perinatal outcome of chorionic villus sampling versus amniocentesis

This study assesses the relative risks of first trimester transcervical chorionic villus sampling (CVS) versus midtrimester amniocentesis performed between April 1986 and March 1988. The most common indication for prenatal diagnosis was advanced maternal age. We discovered 5.1% chromosomal aberrations in CVS compared to 1.0% in amniocentesis. Bleeding was the most frequent early complication, and only 1 case had major hemorrhage with subsequent spontaneous abortion. The fetal loss rate (gestational age less than 28 weeks) was 4.5% in CVS versus 1.2% in amniocentesis, which was not significantly different from the background fetal loss rate reported in normal pregnancies after an 8-week gestational age. Three cases of fetal loss after CVS were probably procedure-related; 1 case had spontaneous abortion and 2 cases had chorioamnionitis. Therefore, we considered that the causal relationship between CVS and the infection was highly probable. The clinical pregnancy outcome indicated that there were no differences in overall perinatal mortality, Apgar score, body weight, body length, gestational age at delivery, intrauterine growth retardation, placenta weight and placental disorders between the CVS group and the amniocentesis group. The pregnancies did not reveal any specific effects of the prenatal diagnostic procedure, but a long-term pediatric follow-up is needed.

Association between dental caries prevalence and Streptococcus mutans among 13-year-old children

The prevalence of caries associated prevalence with Streptococcus mutans in saliva and pooled plaque was investigated among 13-year-old Chinese children. In conjunction with saliva sampling simplified greatly by adopting the oral rinse method, an initial threshold value of 10(4) colony forming units (cfu) per ml of rinse was established on the basis of the S. mutans counts from 27 caries-free individuals. The results of the present study showed that, of the total 58 children, 67.3% had S. mutans counts above the threshold value in their saliva, and they developed significantly more decayed surfaces (D) and decayed, missing, filled surfaces (DMFS) than did the children below this value. The association between caries activity and S. mutans counts either in saliva or in pooled plaque samples was even stronger when only decayed surfaces were taken into account. In addition, the detection frequency of S. mutans (81.8%) was higher in saliva than in the pooled plaque samples (43.2%). This may demonstrate that saliva is more sensitive than dental plaque in predicting caries activity. The most prevalent biotypes of the S. mutans strains observed in this study were c and d. The results of this study indicate a significant association of S. mutans levels with caries prevalence. In the estimation of salivary S. mutans levels, the rinse method offered an easy and rapid identification for children with high caries risk and proved to be very practicable for epidemiological study on a larger scale.

Influence of water fluoridation on the eruption of permanent teeth in Chung-Hsing New Village, Taiwan

Along with an evaluation of the effects of 12 years' water fluoridation in the prevention of caries, the present study was conducted to explore the influence of water fluoridation on the eruption of permanent teeth. The survey was carried out in fluoridated Chung-Hsing New Village and the control town of Tsao-Tun from October to December, 1984. Dental examinations were performed on 3,459 children Chung-Hsing New Village and 4,610 in Tsao-Tun, at ages ranging from 3 to 15 years. The results showed that in general, the mean tooth eruption time of girls was earlier than that of boys, and that teeth in the lower jaw emerge sooner than their homologues in the upper jaw, except for premolars. In both fluoridated and control areas the order of tooth eruption was very similar except for the teeth of girls in the upper jaw. The eruption sequence was first premolar, canine then second premolar in the girls of Chung-Hsing New Village, while first premolar, second premolar then canine in those of Tsao-Tun. By comparing the eruption time of permanent teeth in the children of fluoridated and control areas, it was found that they were very alike in general, the only difference being observed in the premolars of the sexes. The premolars of the children in the fluoridated area emerged in the oral cavity 2.5 to 4.5 months later than did their counterparts in the control area.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic gain factors for fractionated radiation treatment of spontaneous murine tumors using fast neutrons, photons plus O2(1) or 3 ATA, or photons plus misonidazole

Therapeutic gain factors (TGFs) have been determined for three spontaneous tumors of the C3H mouse treated by photons + normobaric oxygen (O2(1) ATA), photons + hyperbaric oxygen (O2 3 ATA), photons + misonidazole, or fast neutrons. The tumors were early generation isotransplants of spontaneous tumors: MCaIV, a mammary carcinoma; FSaII, a fibrosarcoma; and SCCVII, a squamous cell carcinoma. The tumors, transplanted to the right leg, were 6 mm at start of treatment. Normal tissue responses studied were acute reaction of normal skin (all treatment modalities) and LD50 following irradiation of the upper abdomen (in test of photons + O2 at 1 or 3 ATA). Thus both the tumor and normal tissues would be classified as "acute responding." All subject tissues were at congruent to 34.5-35 degrees C at irradiation. Treatments were based on d(25)Be or p(43)Be fast neutron beams, 60Co and 137Cs photon beams. Treatments were given in 5 or 15 equal doses in 5 days. For photon treatments, TGFs (air/O2 3 ATA) were substantially and significantly larger than 1 for all three tumor systems treated at small or large doses per fraction when related to skin or abdominal tissue responses. The TGFs (air/O2 1 ATA) were greater than 1 at small doses per fraction for MCaIV and FSaII for skin as the normal tissue; the TGFs for all three tumors and at all doses per fraction would be greater than 1 when related to upper abdominal tissues. TGFs (O2 1 ATA/O2 3 ATA) for photon irradiation greater than 1 were found only for SCCVII and that obtained for both large and small doses per fraction. Misonidazole achieved impressive TGFs (air/air + miso or air/O2 1 ATA + miso); the drug was tested only at 10-12 Gy/fraction and relative to skin. RBEs(FN) for the three tumors were lower at 1.5-2 Gy(FN)/fraction than at 5-6 Gy(FN)/fraction, i.e. the opposite to that reported for normal tissue (RBE increases with decreasing dose per fraction). A TGF (relative to skin reaction) greater than 1 for fast neutron therapy was found only for SCCVII when treated at large doses/fraction; this was true for air or O2 1 ATA conditions.

The effect of non-differential exposure misclassification on estimates of the attributable and prevented fraction

This paper considers the effect of non-differential exposure misclassification on the population attributable fraction and the population prevented fraction as a function of the sensitivity and specificity of the exposure classification, the true relative risk, and the true prevalence of the exposure. Given a certain set of sensitivity, specificity, and prevalence of the exposure, the apparent attributable fraction is a constant proportion of the true attributable fraction regardless of the true relative risk. This observation does not hold for the apparent prevented fraction and the apparent relative risk, both of which vary with the true relative risk. For both the attributable and the prevented fraction, the sensitivity of the exposure classification has a greater influence on the magnitude of the bias than the specificity; also, the higher the prevalence of the exposure, the larger is the bias caused by the imperfect exposure classification.

Risk factors associated with the prevalence of pulmonary tuberculosis among sanitary workers in Shanghai

The association between potential risk factors and the prevalence of pulmonary tuberculosis was studied in Shanghai Bureau of Sanitation. The study identified a total of 202 cases among 30,289 subjects, and showed that smoking, in particular heavy smoking, had a strong association with tuberculosis after simultaneous adjustment for other factors. Using a multivariate binomial regression, the factors adjusted included the age, sex, history of contact, area of housing and type of work. The relative risk of heavy smokers compared with nonsmokers was 2.17 (95% confidence interval 1.29-3.63). The study showed that although males and old age were associated with a higher risk of tuberculosis than females and young age respectively, these differences were due to the smoking factor. The study also found that the risk of tuberculosis among the subjects with previous patient contacts was twice as high as that among the non-contacts.

Extrahepatic bile duct cancer and smoking, beverage consumption, past medical history, and oral-contraceptive use

Information on potential causal factors in 67 patients with histologically confirmed cancer of the extrahepatic bile ducts was compared with that from 273 patients with other cancers. The control group did not include subjects with tobacco- or alcohol-related cancers. The study subjects were interviewed at 11 large hospitals in eastern Massachusetts and Rhode Island between 1975 and 1979. Among the patients with extrahepatic bile duct cancer, the male-female ratio was 1.5. The use of cigarettes was associated with decreased risk of extrahepatic bile duct cancer. The use of alcohol and coffee was not related to risk of extrahepatic bile duct cancer. Fewer patients than controls reported tea consumption. A statistically significant association between the use of oral contraceptives and extrahepatic bile duct cancer was observed among women under 60 years of age. Patients reported significantly higher frequencies of history of ulcerative colitis or diseases of the gallbladder.

Extrahepatic bile duct cancer and smoking, beverage consumption, past medical history, and oral-contraceptive use

Information on potential causal factors in 67 patients with histologically confirmed cancer of the extrahepatic bile ducts was compared with that from 273 patients with other cancers. The control group did not include subjects with tobacco- or alcohol-related cancers. The study subjects were interviewed at 11 large hospitals in eastern Massachusetts and Rhode Island between 1975 and 1979. Among the patients with extrahepatic bile duct cancer, the male-female ratio was 1.5. The use of cigarettes was associated with decreased risk of extrahepatic bile duct cancer. The use of alcohol and coffee was not related to risk of extrahepatic bile duct cancer. Fewer patients than controls reported tea consumption. A statistically significant association between the use of oral contraceptives and extrahepatic bile duct cancer was observed among women under 60 years of age. Patients reported significantly higher frequencies of history of ulcerative colitis or diseases of the gallbladder.

Death from uveal melanoma. Number of epithelioid cells and inverse SD of nucleolar area as prognostic factors

Criteria for the Callender classification of uveal melanoma are subjective and lead to variations among observers of the same tumor. Two other measures for cell type-the number of epithelioid cells per high-power field (Epi/HPF) and the inverse SD of nucleolar area (ISDNA)-were evaluated as prognostic factors for survival following enucleation for uveal melanoma in 232 patients. Variables significantly related to the number of Epi/HPF were related to ISDNA. Larger, more anteriorly located tumors had a high number of Epi/HPF and a low ISDNA. The two measures were also correlated. Using Kaplan-Meier survival analysis, both measures were related to tumor deaths. Worse prognosis was associated with a higher number of Epi/HPF and a lower ISDNA. Considered together in Cox' proportional hazards analysis, both measures independently predicted outcome. Separately, each measure predicted uveal melanoma-related deaths, in combination with largest tumor dimension, invasion of tumor to the line of transection, and location of the anterior tumor margin. Although ISDNA is the more objective measure of cell type, its practicality compared with other measures of cell type must also be considered.

Tonsillectomy and Hodgkin's disease: results from companion population-based studies

The question of whether persons with a history of tonsillectomy are at increased risk of Hodgkin's disease (HD) in adulthood was evaluated in companion population-based case-control studies conducted in the eastern Massachusetts and the Detroit metropolitan areas. These studies compared the history of tonsillectomy among incident cases with that of all their siblings by matched analysis controlling for confounding by childhood social class, family size, and birth order. Among young adults (15-39 yr) there is substantial evidence that tonsillectomy is not a risk factor and the relative risk (RR) is 1.0 (95% confidence interval, 0.72-1.4). Among middle-aged persons (40-54 yr) the RR is not significantly elevated, 1.5 (0.67-3.3), and the direction of the association differs between the sexes, consistent with the hypothesis of no association. Among older persons, the RR is significantly elevated, 3.0 (1.3-6.9), but the data are sparse. On the basis of these data, it appears unlikely that prior tonsillectomy is a causal factor in the development of HD in young and middle-aged adulthood. Whether it is a risk factor for the malignancy occurring late in life is unclear.

Myoelectric analysis of the paraspinal musculature in relation to automobile driving

In this study, the myoelectric activity of 12 paraspinal muscles of ten men aged 18-24 was recorded to examine the effects of backrest inclination and lumbar support in relation to driving. In total, 24 test conditions were evaluated over a 3.5-hour period in a single day. These tests were then repeated, changing the sequence over the next 4 days. The results indicate a complex interaction between the thoracic and lumbar regions of the back with the lowest myoelectric activity position of 120 degrees backrest inclination, 5 cm of lumbar support, and 13.5-18.5 degrees of seat inclination. Electromyogramatic (EMG) evidence of fatigue was not identified over a 3.5-hour period. The generally low levels of EMG activity and, presumably, disc pressure present in any seating position suggest that the paraspinal muscle activity may not play the predominant role in disc herniation as it relates to automobile driving.

Power calculation in matched case-referent studies. Application and accuracy of the asymptotic power function

Although the asymptotic power function for matched case-referent (case-control) studies has been given, it is not widely applied. One reason for this is that the parameters in the power function do not correspond directly to the usual description of the research situation. When designing a matched case-referent study, the potentially available relevant information concerns the joint distribution of the determinant and matching variate, and the illness rate in relation to those factors, in the study base. Application of the asymptotic power function using these inputs is described. The asymptotic power function is then assessed by use of the Monte Carlo method and is found to be accurate. An example of the application of the asymptotic power function is given.

Visual outcome after proton beam irradiation of uveal melanoma

Prognostic factors for visual loss following proton irradiation of uveal melanoma were evaluated for 440 eyes treated from 1975 to 1984, with visual acuity 20/200 or better before treatment. Analysis involved Kaplan-Meier survival curves and Cox proportional hazards analysis with visual outcome defined as worse than 20/200. Prognostic factors were tumor height: rate ratio (ratio of rate of visual loss for one category of the variable relative to the rate of visual loss for a reference category of that variable) of 5.26 (95% confidence interval, 2.66-10.39) for tumors greater than 5 mm compared to tumors 3.0 mm or less in height; distance of tumor from the optic disc and fovea: rate ratio 2.59 (1.63-4.11) for tumors 2DD or less from both the optic disc and fovea compared to those greater than 2 DD from these structures. Also predictive of visual loss were tumor location close to disc only, or close to fovea only, macular detachment, worse pretreatment vision, and higher radiation doses delivered to both the disc and fovea, and lens. Regression analysis using a visual acuity scale gave similar results.

Prognostic factors for metastasis following proton beam irradiation of uveal melanomas

Prognostic indicators for the development of metastasis following proton beam irradiation of uveal melanomas were evaluated for 510 patients treated from 1975 to 1984. Thirty-three patients developed metastasis (6.5%) from 3 to 51 months following treatment. The primary site of metastasis was the liver in 28 cases (85%). Both demographic and clinical factors were considered. The three leading predictors of survival without metastasis after proton beam irradiation in order of importance were: (1) largest diameter of the tumor; (2) location of the anterior margin of the tumor; and (3) age at treatment. Worse prognosis was associated with largest tumor diameter greater than 15.0 mm, tumor involvement of the ciliary body and age at treatment older than 59 years.

Physical activity, all-cause mortality, and longevity of college alumni

We examined the physical activity and other life-style characteristics of 16,936 Harvard alumni, aged 35 to 74, for relations to rates of mortality from all causes and for influences on length of life. A total of 1413 alumni died during 12 to 16 years of follow-up (1962 to 1978). Exercise reported as walking, stair climbing, and sports play related inversely to total mortality, primarily to death due to cardiovascular or respiratory causes. Death rates declined steadily as energy expended on such activity increased from less than 500 to 3500 kcal per week, beyond which rates increased slightly. Rates were one quarter to one third lower among alumni expending 2000 or more kcal during exercise per week than among less active men. With or without consideration of hypertension, cigarette smoking, extremes or gains in body weight, or early parental death, alumni mortality rates were significantly lower among the physically active. Relative risks of death for individuals were highest among cigarette smokers and men with hypertension, and attributable risks in the community were highest among smokers and sedentary men. By the age of 80, the amount of additional life attributable to adequate exercise, as compared with sedentariness, was one to more than two years.

Adolescent suicidal and self-destructive behavior. Results of an intervention study

This study evaluates an intervention program designed to reduce suicidal, self-destructive behavior among high-risk adolescents aged 13- to 17 years. The intervention combined a program of community education and direct service to youth who had required emergency care for self-inflicted injuries. The intervention program was effective in increasing subjects' compliance with medical regimen. To a lesser degree, the intervention also facilitated early help seeking among adolescents with suicidal thoughts and appeared to diminish slightly the overall occurrence of emergency room admissions for suicidal behaviors. However, the intervention program had no demonstrable effect on the occurrence of repeat suicidal episodes.

Immunological uniqueness of human monoamine oxidases A and B: new evidence from studies with monoclonal antibodies to human monoamine oxidase A

Monoamine oxidase (EC 1.4.3.4; MAO) is the primary enzyme responsible for the intraneuronal degradation of biogenic amines in the central nervous system. An understanding of the physiological significance of the functional and regulatory differences between the two forms of the enzyme, MAOs A and B, would be facilitated by the availability of antibodies specific for the two forms of the enzyme. We previously isolated and characterized a monoclonal antibody (MAO B-1C2, previously designated MAO-1C2) which binds human MAO B but not A. We describe here four new monoclonal antibodies (designated MAO A-3C9, A-4F10, A-7B10, and A-7E10) which were elicited to highly purified MAO A from human placenta and which, in the presence of antimouse IgG and Staphylococcus aureus, immunoprecipitate greater than 90% of the catalytically active purified MAO A. MAO A-3C9 appears to have a lower affinity for purified MAO A than the other three antibodies and does not immunoprecipitate either MAO A or MAO B from human platelets or from Triton X-100 extracts of human placental and liver mitochondria. MAO A-4F10, A-7B10, and A-7E10 immunoprecipitate catalytically active MAO A from Triton X-100 extracts of human placental and liver mitochondria, but not catalytically active MAO B from either pletelets or from Triton X-100 extracts of human liver mitochondria. Collectively, these anti-MAO monoclonal antibodies reveal unique epitopes on human MAO A not shared by MAO B, and at least one epitope on MAO B not shared by MAO A. These immunochemical differences support the hypothesis that MAO A and MAO B are different proteins, presumably isozymes.

Comparison of survival rates for patients with uveal melanoma after treatment with proton beam irradiation or enucleation

We compared survival experiences for three groups with uveal melanoma: (1) 120 patients treated by proton beam irradiation from 1975 to 1981; (2) 235 patients treated by enucleation from 1953 to 1973 (enucleation group 1); and (3) 161 patients treated by enucleation from 1975 to 1981 (enucleation group 2). The following variables were predictive of melanoma-related deaths.

TREATMENT

rate ratio (ratio of the rate of death for one category of the variable relative to the rate of death for another category) of 6.32 (95% confidence interval 1.70 to 23.51) for enucleation group 1 vs proton beam, 3.06 (0.81 to 11.54) for enucleation group 2 vs proton beam, and 2.07 (1.05 to 4.07) for enucleation group 1 vs enucleation group 2. Size: rate ratio of 3.61 (1.51 to 8.64) for large (16+ mm) vs small (less than 11 mm) tumors.

LOCATION

rate ratio of 3.19 (1.56 to 6.53) for tumors anterior vs posterior to the equator. When death from all causes was evaluated as the outcome, the estimated rate ratios were similar. When melanoma metastasis was evaluated as the outcome, the estimated rate ratios were reduced in magnitude.

Note on interval estimation of the difference between proportions from correlated series

This paper presents a procedure for estimating the confidence interval of the difference between proportions in paired observations. As an extension of McNemar's test, this large sample interval estimation procedure uses a variance estimator obtained at the limit and is not conditional on the number of discordant pairs.

Vitamin A supplementation and plasma retinol levels: a randomized trial among women

Although dietary intake of vitamin A has little, if any, overall effect on blood retinol in generally well-nourished populations, subgroups may exist that would be responsive to supplementation. The hypothesis that vitamin A supplementation increases blood retinol in apparently well-fed individuals with lower than usual blood levels was tested in female health workers, with relatively low blood retinol values, who were randomly assigned to receive vitamin A (10,000 IU daily) or placebo. After 4 weeks the mean change in plasma retinol was -0.4 micrograms/dl for the group receiving placebo and +4.1 micrograms/dl (an increase of 9% over base-line values) for the group receiving vitamin A (P = .02). The results were similar when the base-line retinol level and several other covariates were considered. Thirteen women who had initially received placebo were then switched to vitamin A for 4 weeks. These women experienced a mean increase of 5.3 micrograms/dl in plasma retinol (P = .04). Responses to vitamin A supplementation tend to be greater among women with lower previous total vitamin A intake, as assessed by questionnaire [Spearman rank correlation coefficient (r) = 0.50; P = .01].

Apnea of infancy and subsequent neurologic, cognitive, and behavioral status

A pilot study investigated the neurologic, cognitive, and behavioral consequences of nonfatal infancy apnea. Fifteen formerly apneic, monitored children were compared with age-similar siblings and with age-sex matched playmates. Significant impairment in gross motor development and mild cognitive deficiencies were observed when those who had had apnea were compared with their siblings but not when contrasted with their playmates. Lack of difference between those who had had apnea and playmates might have been due to a selection bias involving assortive friendships. The frequency and the severity of apneic episodes were associated but neither one showed a clear gradient of risk for poor outcome in the areas under study, indicating the possibility that apnea may have a threshold effect on subsequent development.

Age at first birth and breast atypia

The relation between age at first birth and the occurrence of fibrocystic breast disease of different atypia subtypes was evaluated using data from a cohort study of the health effects of oral-contraceptive use. Multivariate case-control analysis was performed on 218 parous women with biopsied fibrocystic disease and 928 parous controls. Fibrocystic breast disease, as a whole and as atypia subtypes, was found to be unrelated to age at first birth. Furthermore, the estimated effect of age at first birth did not vary from one atypia subtype to another. Women with high parity were found to be at decreased risk of fibrocystic breast disease compared to those with low parity. Age at completion of education, used as an indicator of socioeconomic status, was found to be moderately associated with fibrocystic breast disease. The estimated effect of parity and age at completion of education also did not vary among subtypes. More epidemiologic studies specific to histopathologic classifications of benign breast disease are called for.

Oral contraceptive use and fibrocystic breast disease of different histologic classifications

The relationship between oral contraceptive (OC) use and occurrence of fibrocystic breast disease (FBD) of different histologic classifications was evaluated with data from a cohort study. Biopsy specimens from 232 women with FBD were classified into different atypia categories. In 96 matched pairs of OC users and nonusers, atypia scores were lower in users than in nonusers. Women without breast diseases (500 OC users and 500 nonusers) were sampled from the original cohort to form a two-stage "anamorphic" study with the 232 cases of FBD. The previously shown inverse association between OC use and FBD occurrence was present and increased with increased length of OC use. However, the "protective effect" of OC use did not vary for different histologic classifications of FBD. The findings from both paired and anamorphic analyses of the data are not consistent with the hypothesis that the use of OC is associated with decreased frequency only of FBD with minimal epithelial atypia.

Age at any birth and breast cancer risk

In an effort to assess the relative importance of age at first birth, age at subsequent births, and total parity to the occurrence of breast cancer, reproductive data from 4,225 women with breast cancer and 12,307 hospitalized women without breast cancer were analyzed by a multiple logistic regression model. Age at first birth was confirmed to be the most important reproductive risk indicator; it was associated with a 3.5% increase of relative risk for every year of increase in age at first birth (the 95% confidence interval of this estimate was 2.3 to 4.7% increase per year). However, age at any birth after the first was also an independent and statistically significant risk indicator; it was associated with a 0.9% increase of relative risk for every year of increase in age at any (and every) birth (the 95% confidence interval of this estimate was 0.4 to 1.5% increase per year). There is evidence that the age of approximately 35 years represents for every birth a critical point; before this age any full-term pregnancy confers some degree of protection; after this age any full-term pregnancy appears to be associated with increase in breast cancer risk. The effect of parity is determined by the age of occurrence of the component pregnancies. While most pregnancies occur under the age of 35, the distribution varies from population to population, and this may account for the differences between populations in whether or not a protective effect is seen for births after the first, and if it is seen, its extent.

Grouping occupations according to carcinogenic potential: occupation clusters from an exposure linkage system

An occupational clustering scheme has been developed from an occupation and exposure linkage system. In this scheme, occupational titles are grouped together hierarchically according to the numbers and degrees of their shared exposures. The use of the clusters obtained from this hierarchy is demonstrated in the analysis of the data from a case-control study of bladder cancer.

Consumption of alcohol and tobacco and other risk factors for pancreatitis

Histories of alcohol and tobacco consumption and other potential risk factors were obtained from 98 patients with pancreatitis and 451 comparison patients at 11 large hospitals in Eastern Massachusetts and Rhode Island between 1975 and 1979. The great majority of the patients with pancreatitis had chronic or recurrent disease. From the comparison patients were excluded patients with other diseases of the pancreas and biliary tract and those admitted for disorders known to be associated with smoking or alcohol use. A statistically significant association of pancreatitis with alcohol use was present in males, but not in females. Cigarette use was very strongly associated with pancreatitis in males and less so in females. The associations with alcohol and cigarette use were independent, each retaining significance after adjustment for the other. There was no significant association of risk with coffee consumption in either sex. A history of biliary tract disease was given by 45 per cent of the male and 60 per cent of the female cases. The associations with alcohol use and cigarette smoking did not appear to be restricted either to the patients with or those without a history of biliary tract disease. Chronic or recurrent pancreatitis appears to have different dominant etiologies in males and females.

Reactions of powdered human enamel and fluoride solutions with and without intermediate CaHPO4 x 2H2O formation

Powdered human enamel treated for three minutes each with a CaHPO4 x 2H2O forming solution and a fluoride solution, and then suspended in "synthetic saliva" for 72 hours acquired a large amount of apatitic fluoride. This apatitic fluoride appears to form after the fluoride treatment.

Studies on Thermoactinomyces sp. TM9208. I. Description of the strain

A strain of Thermoactinomyces sp., TM9208, isolated from a soil sample in the Taipei area showed antagonistic activity to Gram positive bacteria but not to the Gram negative on the potato extract agar plate by the cross streaking method. The strain showed strong starch hydrolysis, beta type of hemolysis, brownish yellow growth on the potato extract agar and green on the nutrient agar. Its aerial mycelium, white to grayish white, was long and straight with short branches. The spores are single and have smooth surface. It is a good utilizer of starch, maltose and cellobiose as carbon source, but utilizes dulcitol, salicin, sucrose, rhamnose and sorbitol poorly.