A genome screen of families with multiple cases of prostate cancer: evidence of genetic heterogeneity.

We conducted a genomewide screen for prostate cancer-susceptibility genes on the basis of data from 98 families from the United States and Canada that had three or more verified diagnoses of prostate cancer among first- and second-degree relatives. We found a statistically significant excess of markers for which affected relatives exhibited modest amounts of excess allele-sharing; however, no single chromosomal region contained markers with excess allele-sharing of sufficient magnitude to indicate unequivocal evidence of linkage. Positive linkage signals of nominal statistical significance were found in two regions (5p-q and 12p) that have been identified as weakly positive in other data sets and in region 19p, which has not been identified previously. All these signals were considerably stronger for analyses restricted to families with mean age at onset below the median than for analyses of families with mean age at onset above the median. The data provided little support for any of the putative prostate cancer-susceptibility genes identified in other linkage studies.

Premorbid diet in relation to survival from prostate cancer (Canada).

OBJECTIVES: To examine the associations between prediagnostic energy, fat, and vitamin A intake and survival from prostate cancer. METHODS: Two hundred and seven cases of prostate cancer from Toronto and 201 cases from Vancouver provided diet histories at diagnosis between 1989 and 1992 and were followed for survival from prostate cancer. After exclusions for various reasons, 263 cases (135 from Toronto, 128 from Vancouver) were analyzed in Cox proportional hazards models. RESULTS: Following adjustments for clinical stage, histologic grade, and other factors, significantly lower risks of dying from prostate cancer in the highest compared with the lowest tertiles of monounsaturated fat intakes were observed in each city and in the combined city analyses (combined cities: hazard ratio [HR] = 0.3; 95% confidence interval (CI) = 0.1-0.7). Survival from prostate cancer was significantly better for cases in the highest tertile of energy intake in Toronto (HR = 0.1; CI = 0.01-0.6) in contrast to that in Vancouver where these cases did relatively worse (HR = 2.6; CI = 0.6-10.7). Other nutrients were either not consistently or not significantly associated with prostate cancer survival in the two cities. CONCLUSIONS: This bi-center cohort study observed a consistent and significant inverse association between the premorbid intake of monounsaturated fat and risk of death from prostate cancer. The inconsistent results for energy intake between cities could potentially be attributed to non-respondent bias in Toronto.

Cigarette smoking and risk of prostate cancer: a population-based case-control study in Ontario and British Columbia, Canada.

The relationship between cigarette smoking and risk of prostate cancer was examined in a case-control study conducted in Ontario and British Columbia, Canada. In each centre, cases were men with a histologically confirmed diagnosis of adenocarcinoma of the prostate notified to the provincial cancer registry. In Ontario, controls were selected randomly from assessment lists maintained by the Ontario Ministry of Revenue and were frequency matched to the cases on age. In British Columbia, controls were also frequency matched to the cases on age and were selected randomly from a roster maintained by the Medical Services Plan of British Columbia. The study in Ontario was conducted between April 1990 and April 1992, and that in British Columbia was conducted between January 1989 and December 1991. In all, the study included 408 cases (207 in Ontario and 201 in British Columbia) and 407 controls (207 in Toronto and 200 in British Columbia (one case was unmatched). Overall, there was little variation in risk of prostate cancer with pack-years of cigarette consumption (filter and non-filter cigarettes combined), and there was no evidence for an effect confined to filter or non-filter cigarettes. There was some evidence for a positive association with non-filter cigarettes in British Columbia, but on formal testing for heterogeneity, this finding was not inconsistent with the absence of an association in Ontario. There was also little variation in risk by years since first smoked or (for ex-smokers) by years since quitting. These data provide little support for an association between cigarette smoking and prostate cancer risk.

Serum androgens and sex hormone-binding globulins in relation to lifestyle factors in older African-American, white, and Asian men in the United States and Canada.

Differences in endogenous androgen levels have been hypothesized to explain ethnic differences in prostate cancer risk. To examine this hypothesis, we gathered data on serum concentrations of androgens and sex hormone-binding globulin (SHBG) in healthy older men from four ethnic groups at different levels of prostate cancer risk. As part of a population-based case-control study of prostate cancer we conducted in California, Hawaii, and Vancouver, Canada, 1127 African-American, white, Chinese-American, and Japanese-American control men, mostly ages 60 years or older (mean age, 69.9 years) provided information on various lifestyle factors and donated an early morning fasting blood sample between March 1990 and March 1992. We used these data to examine the distributions of serum androgens [testosterone (total, free, and bioavailable), dihydrotestosterone (DHT)], the ratio of DHT to total testosterone (DHT:testosterone ratio), and SHBG in these four ethnic groups. We also assessed correlations between concentrations of these measures with age, body size, physical activity, and other personal characteristics, and we evaluated ethnic differences in concentrations of androgens and SHBG after adjusting for these characteristics. In each of the four ethnic groups, concentrations of free and bioavailable testosterone declined with age, whereas SHBG concentrations increased with age. Age-adjusted concentrations of all androgen measures and SHBG decreased with increasing levels of Quetelet's index. After adjustment for age and Quetelet's index, androgens and SHBG showed no clear and consistent relationships to physical activity, alcohol consumption, or tobacco use. DHT:testosterone ratio was higher in men reporting a history of benign prostate disease than in men without such a history, and higher in vasectomized men than in nonvasectomized men. SHBG concentrations were higher in men reporting one or more first-degree relatives with prostate cancer than in men without such a family history. After adjustment for age and Quetelet's index, the levels of total and bioavailable testosterone were highest in Asian-Americans, intermediate in African-Americans, and lowest in whites. However, the DHT:testosterone ratio was highest in African-Americans, intermediate in whites, and lowest in Asian-Americans, corresponding to the respective incidence rates in these groups and providing indirect evidence for ethnic differences in 5alpha-reductase enzyme activity.

Vasectomy and prostate cancer: results from a multiethnic case-control study.

BACKGROUND: Vasectomy, a widely used form of contraception, has been associated in some studies with increased prostate cancer risk. PURPOSE: We assessed this association on the basis of data collected in a large multiethnic case-control study of prostate cancer that was conducted in the United States (Los Angeles, San Francisco, and Hawaii) and Canada (Toronto and Vancouver). METHODS: In home interviews conducted with newly diagnosed prostate cancer case patients and population control subjects, we obtained information on the participants' medical history, including a history of vasectomy and the age at which the procedure was performed, as well as other potential risk factors. Blood samples were collected from control subjects only and were assayed for concentration of sex hormones and sex hormone-binding globulin. RESULTS: The present analysis was based on 1642 prostate cancer patients and 1636 control subjects. A history of vasectomy was not significantly associated with prostate cancer risk among all racial/ethnic groups combined (odds ratio [OR] = 1.1; 95% confidence interval [CI] = 0.83-1.3), whites (OR = 0.94; 95% CI = 0.69-1.3), blacks (OR = 1.0; 95% CI = 0.59-1.8), or Chinese-Americans (OR = 0.96; 95% CI = 0.42-2.2). Among Japanese-Americans, the OR was 1.8 (95% CI = 0.97-3.4), but the statistically nonsignificant elevation in risk was limited to more educated men and those with localized cancers. ORs did not vary significantly by age at vasectomy or years since vasectomy. We found a lower serum concentration of sex hormone-binding globulin and a higher ratio of dihydrotestosterone to testosterone among vasectomized control subjects than among nonvasectomized control subjects. CONCLUSIONS: The findings of this study do not support previous reports of increased prostate cancer risk associated with vasectomy. However, the altered endocrine profiles of vasectomized control subjects seen in this cross-sectional comparison warrant further evaluation in longitudinal studies.

PIP: Vasectomy has been associated in some studies with increased prostate cancer risk. This association was assessed on the basis of data collected in a large multiethnic case control study of prostate cancer that was conducted in the United States (Los Angeles, San Francisco, and Hawaii) and Canada (Toronto and Vancouver). In home interviews conducted with newly diagnosed prostate cancer case patients (diagnosed between January 1, 1989 and December 31, 1991 as well as January 1, 1987 and December 31, 1988) and control subjects, information was obtained on the participants' medical history, including a history of vasectomy and the age at which the procedure was performed as well as other potential risk factors. Blood samples were collected from control subjects only and were assayed for concentration of total testosterone, percent of free testosterone, percent of bioavailable testosterone, dihydrotestosterone (DHT), and sex hormone-binding globulin (SHBG) using an automated, polyclonal-monoclonal immunochemiluminometric prostate-specific antigen (PSA) assay. The analysis was based on 1642 prostate cancer patients and 1636 control subjects. The analysis of PSA, androgens, and SHBG by vasectomy status was based on 850 control subjects with normal PSA concentrations. A history of vasectomy was not significantly associated with prostate cancer risk among all racial/ethnic groups combined (odds ratio [OR] = 1.1; Whites OR = 0.94; Blacks OR = 1.0; or Chinese-Americans OR = 0.96). Among Japanese-Americans, the OR was 1.8, but the statistically significant elevation in risk (OR = 4.1) was limited to more educated men with a history of vasectomy and those with localized cancers (OR = 5.3). ORs did not vary significantly by age at vasectomy or years since vasectomy. Lower serum concentration of SHBG and a higher ratio of DHT to testosterone was found among vasectomized control subjects than among nonvasectomized control subjects. The findings do not support previous reports of increased prostate cancer risk associated with vasectomy. However, the altered endocrine profiles of vasectomized control subjects warrant further evaluation in longitudinal studies.

Family history and prostate cancer risk in black, white, and Asian men in the United States and Canada.

Increased risk of prostate cancer in men with a family history of the disease has been observed consistently in epidemiologic studies. However, most studies have been confined to white men; little is known about familial aggregation of prostate cancer in populations with unusually high incidence, such as African Americans, or in populations with low incidence, such as Asian-Americans. The authors report results from a population-based case-control study of prostate cancer among blacks, whites, and Asian-Americans in the United States and Canada. Controls were matched to cases on age (5-year groups), ethnicity (black, white, Chinese-American, Japanese-American), and region of residence (Los Angeles, San Francisco, Hawaii, Vancouver, Toronto). In the combined group of participants, 5% of controls and 13% of cases reported a father, brother, or son with prostate cancer. These prevalences were somewhat lower among Asian-Americans than among blacks or whites. A positive family history was associated with a statistically significant two- to threefold increase in risk in each of the three ethnic groups. The overall odds ratio associated with such a family history, adjusted for age and ethnicity, was 2.5 (95% confidence interval 1.9-3.3). This odds ratio varied by neither ethnicity nor age of the participants. Sera from 1,087 controls were used to examine the relations between family history and serum concentrations of androgens and prostate-specific antigen. The concentrations of sex hormone-binding globulin were slightly higher in men with than without a positive family history. Prostate-specific antigen concentrations were unrelated to family history.

Comparison of dietary habits, physical activity and body size among Chinese in North America and China.

BACKGROUND: Chinese in North America have higher rates of many chronic diseases than do Chinese in Asia. However, there is a lack of data among comparisons of the environmental and lifestyle factors for Chinese in China and Chinese residing in North America. METHODS: We examined self-reported dietary nutrient intakes, physical activity patterns and body mass index of 2488 healthy Chinese men and women residing in North America (US and Canada) and in the People's Republic of China. RESULTS: On average, Chinese in China consumed more calories (males 2904 kcal in China, versus 2201 kcal in North America; females 2317 Kcal in China, versus 1795 Kcal in North America and more carbohydrate, but less fat (males 72.2 g in China versus 84.5 g in North America, females 56.6 g in China versus 70.8 g in North America), protein, vitamin A, beta-carotene and vitamin C than did Chinese in North America. Per cent calories from fat was 35% for Chinese in North America and 22% for Chinese in China. In contrast, the per cent of calories from carbohydrates was 62-68% in China and 48% in North America. Chinese in China reported spending more time in vigorous activity, sleeping and walking but less hours in sitting than Chinese in North America. Chinese in China weighted less and were leaner than North American Chinese. CONCLUSIONS: These differences in nutrient intakes, physical activity and body size of Chinese living on two different continents suggest possible explanations for observed differences in chronic disease rates in the two populations.

History of circumcision, medical conditions, and sexual activity and risk of penile cancer.

BACKGROUND: Epidemiological evidence suggests lack of neonatal circumcision as the strongest risk factor for penile cancer, but the role of sexually transmitted diseases in the etiology of penile cancer has remained unclear. PURPOSE: To further clarify risk factors for penile cancer, we examined the role of circumcision, personal characteristics and habits (such as smoking), sexually transmitted diseases, past sexual activity, and medical conditions of the penis. METHODS: A population-based, case-control study was conducted in western Washington state and in the province of British Columbia. We interviewed 110 men with penile cancer diagnosed from January 1979 to July 1990 and 355 control subjects from the general population, frequency matched to case subjects on age and date of diagnosis. Tumor tissue from 67 case subjects was tested for human papillomavirus (HPV) DNA by polymerase chain reaction. Results of blood tests from 69 case subjects and 208 control subjects were available for study. STATISTICALLY SIGNIFICANT RESULTS: Relative to men circumcised at birth, the risk for penile cancer was 3.2 times greater among men who were never circumcised and 3.0 times greater among men who were circumcised after the neonatal period. For current smokers, the risk was 2.8 times that of men who never smoked. The risk among men reporting a history of genital warts was 5.9 times that of men reporting no such history. Of 67 tumors tested for HPV DNA, 49% were positive; the majority of these positive tumors (70%) were type 16, which has been associated with anogenital carcinoma. Relative risks (RRs) associated with a reported history of penile rash or penile tear were 9.4 and 3.9, respectively. Among men not circumcised at birth, RRs associated with presence of smegma and difficulty in retracting the foreskin were 2.1 and 3.5, respectively. Twenty-eight percent of case subjects, compared with only 10% of control subjects, reported 30 or more sexual partners, and men with HPV-positive tumors were more likely to report a greater number of sexual partners. CONCLUSIONS: These results suggest that the absence of neonatal circumcision and potential resulting complications are associated with penile cancer. Additionally, medical conditions of the penis, sexual activity, infection with HPV, and smoking may increase the risk for penile cancer. IMPLICATIONS: A larger study would allow examination of interrelationships of circumcision, infection with HPV, and smoking as risk factors.

Synthesis and antiviral activity of 11-azapentacyclo[6.2.1.0.0.0]decane.

11-Azapentacyclo[6.2.1.0.0.0]decane (6a) as well as its 6,7-dimethyl derivative 6b was synthesized by a novel, four-step sequence that holds promise for the construction of a variety of cage compounds with bridging nitrogen atoms. The hydrochloride salt of 6a was shown to possess no antiviral activity against either the influenza virus A/Victoria/3/75 or the herpes simplex viruses HSV-1 and HSV-2.

Generation of mouse oocyte monoclonal isoantibodies: their effects and those of antisperm monoclonal antibodies on in vitro fertilization.

Monoclonal isoantibodies to mouse oocyte antigens were generated by modified hybridoma techniques similar to those described for mouse sperm monoclonals. Following isoimmunization with mouse oocytes and cell fusion, hybrid cells were cultured initially in a semi-solid medium containing methylcellulose. Seven to ten days after cell fusion about 350 hybrid clones were recovered for subculture. By an indirect immunofluorescence assay using frozen or fresh mouse oocytes, twenty hybridomas were shown to produce antibodies that bind to various oocyte components including antigens of the zona pellucida. However, they did not cross-react with mouse spermatozoa or lymphocytes. A system was established to evaluate whether monoclonal antibodies to gamete-specific antigens have any inhibitory effects on the fertilization of mouse oocytes in vitro. A monoclonal antibody against zona antigen(s), ME 56, was shown to block fertilization of mouse oocytes via the inhibition of sperm binding to the zona pellucida. On the other hand, three out of four antibodies reacting with mouse sperm acrosomes were also inhibitory to mouse in vitro fertilization, perhaps mainly due to the inhibition of sperm acrosomal reactions. Using a sodium dodecylsulfate gel/protein blot radioimmunobinding method, the molecular weight of zona antigen(s) that react with ME 56 was determined to be in the range of 95,000, whereas that of the acrosomal antigen(s) reacting with the fertilization-inhibiting antibody, MS 207, was about 30.000. The results of this preliminary study suggest that monoclonal antibodies to certain gamete antigens can be a valuable tool for the analysis of sperm-egg interactions during the fertilization processes.

Analysis of mouse sperm isoantigens using specific monoclonal antibodies.

Female mice were isoimmunized with homologous spermatozoa of the same strain. Hybrid cells that secrete monoclonal antibodies to mouse sperm isoantigens were generated by modified hybridoma techniques using a semi-solid Iscove's modified Dulbecco's medium containing methylcellulose for the initial cloning. Out of more than 1,000 colonies that were initially recovered for subculture, 246 were shown to produce antibodies reacting with various cytological regions of mouse spermatozoa, when methanol-fixed sperm were employed in an indirect immunofluorescent assay. More than 75% of the generated monoclonal isoantibodies were shown to bind the acrosomal regions of mouse spermatozoa. Some were found to cross-react with spermatozoa from other mammalian species including those of human, rabbit, rat, and guinea pig. However, none were shown to cross-react with mouse lymphocytes. Two-thirds of the generated monoclonal antibodies can also bind live mouse spermatozoa. By an immunohistochemical technique using testicular sections, some of these monoclonal antibodies were shown to react with specific antigens expressed during different stages of spermatogenesis. It is concluded that these mouse sperm isoantigens are sperm-specific and appear uniquely during spermatogenesis. Monoclonal isoantibodies produced in the present study may have potential applications regarding the investigations of sperm iso- or autoimmunity, spermatogenesis, and fertility control.

Generation of monoclonal antibodies to human chorionic gonadotropin by a facile cloning procedure.

A facile hybridoma procedure has been used to generate monoclonal antibodies to alpha- and beta-subunits of human chorionic gonadotropin (HCG). The procedure is based on the method of Davis et al. (1982, J. Immunol. Methods 50, 161) and involves the use of a semisolid medium containing methylcellulose for the initial cloning of hybrid cells following immunization and cell fusion. Seven to ten days after cell fusion, viable hybrid clones were removed for subculture in a liquid medium containing RPMI 1640 and 15% fetal calf serum. Initial screening of hybrid cell lines that secrete antibodies to HCG was performed on microplate enzyme-linked immunoassay (ELISA) using HCG-coated microtiter plates. The specificity of these antibodies to either alpha- or beta-subunits was determined by the sodium dodecyl sulfate-gel/protein blot radioimmunobinding method which separates alpha- and beta-subunits of HCG on nitrocellulose strips for radioimmunobinding assay. As a result of this study, it has been possible to generate about 272 hybrid cell lines that secrete antibodies reacting with either the alpha- or beta-subunit of HCG in about 5 weeks. The association constants and cross-reactivities to luteinizing hormone for some of the HCG monoclonal antibodies were determined. The high affinity and specificity of these monoclonal antibodies permit their clinical application in a sensitive sandwich solid-phase enzyme-linked and radioimmunoassay of HCG.

Serotyping of herpes simplex virus isolates: a comparison of BVDU sensitivities, indirect immunofluorescence with monoclonal antibodies, and indirect immunofluorescence with cross-adsorbed rabbit antibodies.

Four methods for typing of herpes simplex virus (HSV) isolates were compared for 43 recent clinical isolates and 3 reference strains of HSV. These isolates were subjected to indirect immunofluorescence using both monoclonal antibodies and cross-adsorbed rabbit antisera. Sensitivity to E-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) was also examined. All isolates which fluoresced with HSV-1 monoclonals were found to be sensitive to BVDU with ID50's ranging from 0.001 to 0.006 micrograms/ml. All isolates labelled as HSV-2 using monoclonal antibodies had ID50's to BVDU ranging from 0.4 to 3.5 micrograms/ml. Results of typing with rabbit cross-adsorbed antisera were less accurate, however. When dilutions were predetermined according to manufacturer's instructions, only 3 of 22 isolates (14%) of HSV-1 were correctly typed. HSV-2 isolates were correctly labelled in 24 of 26 situations (92%). When fluorescence dilution endpoints were compared, however, 21 of 22 (95%) HSV-1 isolates had fluorescence endpoints at a greater dilution with HSV-1 antiserum. Twenty-three of 24 HSV-2 isolates were also correctly typed (96%).

Susceptibility of recent clinical isolates of herpes simplex virus to 5-ethyl-2'-deoxyuridine: preferential inhibition of herpes simplex virus type 2.

We examined the in vitro susceptibilities of three reference strains and 41 recent clinical isolates of herpes simplex virus types 1 and 2 to 5-ethyl-2'-deoxyuridine. This thymidine analog exerts a type 2-preferential but not a type 2-specific antiviral effect. Utilizing a microtiter assay with BHK-21 cells, we found that the mean (+/- standard deviation) 50% inhibitory dose for herpes simplex virus type 1 isolates was 0.58 +/- 0.30 micrograms/ml as compared with 0.33 +/- 0.20 microgram/ml for herpes simplex virus type 2 isolates. Isolates were typed according to their susceptibilities to (E)-5-(2-bromovinyl)-2'-deoxyuridine and by an indirect fluorescent-antibody technique in which monoclonal antibody combinations were used. A cytotoxicity assay in which the incorporation of [1',2'-3H]deoxyuridine was measured revealed a 50% inhibitory dose of 37.5 micrograms/ml, suggesting a favorable therapeutic index for this compound.

Transmissibility of influenza viruses in hamsters.

The growth characteristics of a series of influenza A viruses in the turbinates and lungs of hamsters was measured: in addition, the susceptibility of hamsters to infection by these viruses was also determined. These two criteria were used to give estimates of the growth potential of influenza viruses in hamsters, and the results were related to the incidence of transmission of virus from inoculated hamsters to cage-contacts. The results showed that strains of influenza virus reported as virulent for man tended to grow to higher titres in hamster nasal washings and lungs; were more infective for hamsters when inoculated by the intranasal route; and showed a high incidence of spread to cage-contacts. The methods could provide valuable measurements of virus attenuation and transmissibility for man, and the further exploitation of these techniques could facilitate the production and licensing of live, attenuated influenza virus vaccines.

The replication of type A influenza viruses in the infant rat: a marker for virus attenuation.

Twenty recombinant influenza virus strains bearing HSw1N1, H1N1 or H3N2 surface antigens, together with their respective wild-type or laboratory-propagated parent viruses, were inoculated into 2 day-old infant rats and their replication in the turbinates and lungs of these animals observed over a period of 5 days. In addition, the ability of each of the recombinant and parent viruses to enhance a subsequent infection of these infant rats by Haemophilus influenzae type b was determined. The results showed that both parent and recombinant viruses replicated less well in the lungs than in the turbinates of infant rats, but the titres in both tissues were generally lower for the recombinant strains. The capacity of the majority of the recombinant influenza viruses to promote bacterial infection of the infant rats, as determined by the incidence of H. influenzae bacteraemia and meningitis, was also markedly less than that of their parent viruses. A correlation between virulence for man and both the replication in infant rat turbinates and the ability to enhance H. influenzae infection, was established for the virus strains studied. The data are discussed in relationship to the value of the infant r-H influenzae system as a laboratory marker for the determination of the virulence of influenza virus strains.