The study described here investigates the replicability of gender-specific risk profiles for gonorrhea based on an Alaskan sample compared to a U.S. national sample of drug users at risk for HIV infection. The Alaska sample (interviewed at a field station in Anchorage, Alaska; N=1,049) and the national sample (interviewed at 18 sites other than Alaska; N=17,619) consisted of cocaine smokers and injection drug users not in drug treatment. A history of gonorrhea infection was self-reported and coded as ever or never. The Anchorage and national risk profile for men included the following factors: (a) history of intranasal or parenteral cocaine use, (b) being black versus nonblack, (c) being older, (d) income from illegal activity, and (e) history of amphetamine use. The Anchorage and national risk profiles for women included the following factors: (a) trading sex for money, (b) being Native American versus non-Native American, and (c) trading sex for drugs. The Anchorage model for women included perceived homelessness as a factor, but it was not retained in the national model. The extent of the replicability of these models illustrates the generalizability of Alaskan findings to other U.S. drug-using populations. The authors also discuss the implications of these findings for disease prevention.
Defective mismatch repair has recently been implicated as the major contributor towards the mutator phenotype observed in tumour cell lines derived from patients diagnosed with hereditary non-polyposis colon cancer (HNPCC). Cell lines from other cancer-prone syndromes, such as xeroderma pigmentosum, have been found to be defective in nucleotide excision repair of damaged bases. Some genetic complementation groups are defective specifically in transcription-coupled excision repair, although this type of repair defect has not been associated with cancer proneness. Mechanisms contributing to the high incidence of activating point mutations in oncogenes (such as H-ras codon 12) are not understood. It is possible that novel mechanisms of misrepair or misreplication occur at these sites in addition to the above DNA repair mechanisms. In this study, we have compared the rate of strand-directed mismatch repair of four mispairs (G:A, A:C, T:C and G:T) at the H-ras codon 12, middle G:C position. Our results indicate that, although this location is not a 'hot spot' for bacterial mismatch repair, it is a 'hot spot' for decreased repair of specific mismatched bases within NIH 3T3 cells. NIH 3T3, unlike Escherichia coli, have an extremely low repair rate of the G:A mispair (35%), as well as the A:C mispair (58%) at this location. NIH 3T3 also have a moderately low repair rate of the T:C mispair (80%) at the codon 12 location. Conversely, NIH 3T3 repair of G:T (100%) is comparable to E. coli repair (94%) of this mismatch. These results demonstrate that a mismatch containing an incorrect adenine on either strand at the H-ras codon 12 middle base pair location is most likely to undergo a mutational event in NIH 3T3 cells. Conversely, a mismatch containing an incorrect thymine in the transcribed strand is least likely to undergo a mutational event.
Increasing perception of healthy reproductive functioning and conception prevention has been accompanied by greater recognition of the needs for emotional and sexual fulfillment of individuals with mental disorder or retardation. Although family planning services have burgeoned in the United States and many other countries and the special concerns of mentally disordered and retarded persons have been well documented, organized efforts to include counseling on fertility regulation in mental health and in training programs have, with few exceptions, been sparse. Recent trends are discussed in terms of reported experience from the United States and Denmark. It is recommended that women of childbearing age in psychiatric facilities be given an opportunity to participate in programs offering screening for and treatment of gynecological conditions, as well as family planning counseling, before going on home leave or discharge. Such counseling should be adapted to a woman's emotional functioning, consider possible contraindications of specific contraceptive methods, and, to the extent possible, involve the partner. Ethical aspects need to be considered to avoid even the appearance of coercion. Similar opportunities should be provided for retarded persons seeking to achieve a satisfying sexual life. Surgical contraception and abortion are discussed within the context of patient rights, competence, and the desirability of avoiding unintended conceptions and reducing unwanted births that may engender further stress and psychosocial difficulties for the woman, the child, and society. The experience of former patients might well be useful in restructuring current service programs and priorities.
Alcohol research in Alaska Native communities has a contentious history. This project has attempted to address a critical need for research to guide alcohol abuse prevention and treatment with Alaska Natives using culturally anchored participatory action research. The process of grounding the research methodology in the culture and community is described, along with its contribution to community psychology's understanding of the importance of cultural factors. Tensions between indigenous values and ways of knowing, and Western research methodologies are delineated, along with how these tensions were resolved. Important issues that arose in doing culturally anchored participatory action research are described. These included the development of a community of inquiry, key methodological decisions, the empowerment of participants as coresearchers, and flexibility in research implementation.
Pronounced and persistent seasonal patterns in fertility are observed in virtually all human populations. This paper presents evidence on these seasonal patterns. We note that the most pronounced seasonal patterns are in the southern United States, where births decline substantially in April and May, and in northern Europe, where births increase substantially in March and April. Although seasonal variations in fertility were more pronounced in earlier agricultural populations, we show that seasonality has increased in this century in some high income, low fertility populations such as Sweden. We use data on monthly temperature to analyze the potential role of temperature in explaining seasonal patterns. We find strong evidence that summer heat plays an important role in explaining the July-August trough in conceptions in the southern United States. We find little evidence, however, that temperature plays any role in explaining the pronounced June-July peak in conceptions in Sweden. Temperature also appears to be relatively unimportant in several other populations with substantial seasonal variations in births, suggesting that other factors play an important role in birth seasonality.
It was not known until recently whether the endemic of cholesterol gallstones among certain southwestern American Indian tribes was unique among this ethnic group. With use of ultrasonography of the gallbladder and standard diagnostic criteria, gallstones are now found in epidemic proportions in 13 diverse American Indian tribes and communities living in Arizona, Oklahoma, and the Dakotas. We speculate that this predisposition is polygenic involving "thrifty" genes that conferred survival advantages when Paleo-Indians migrated from present-day Siberia to the Americas during the last Great Ice Age approximately 50,000 to 10,000 years ago. A reasonable hypothesis is that functioning of these genes promoted more efficient calorie utilization and storage in the form of adipose tissue. Beneficial results would have been operative during the isolation of Paleo-Indians in the Bering Strait land bridge (Beringia) when thrifty genes would have ensured sufficient fat reserves for survival of prolonged winters, successful pregnancy outcomes, and extended lactation periods. The authors' conjoint work on genetics of experimental cholesterol cholelithiasis in inbred mice promises help in pinpointing orthologous genetic loci (LITH genes) in the human genome. Moreover, the shared environments and homogeneity of American Indian tribes and communities should facilitate discovery of the ensembles of their common and rarer cholesterol gallstone genes. It is anticipated that knowledge of expression, polymorphisms, and functionality of LITH genes will help resolve the molecular mechanisms of this complex heterogeneous trait and thereby provide targets for novel therapies to prevent cholesterol cholelithiasis worldwide.
Many infectious diseases have been hypothesized to represent common virus infections in which only small proportions of cases result in clinically recognizable disease. In order to find a method of studying this class of diseases, a mathematical model of the age distribution of clinical disease was developed using poliomyelitis as a prototype. The model is shown to fit the age distribution of reported poliomyelitis in a variety of localities before the use of artificial immunization. The true yearly rate of infection is easily estimated and ranges from .11 in rural Sweden to 1.20 in Chile. The model accounts for several major features of poliomyelitis epidemiology, including the shift to older ages and the high rate of clinically apparent disease which were frequently observed in populations which could be expected to have a comparatively low rate of spread. An examination of the age distribution of other diseases by these methods may provide a method of identifying other common infections which only occasionally result in clinically apparent disease.
Data collected for 10 years following the Chernobyl accident in 1986 have provided a unique opportunity to test the reliability of computer models for contamination of terrestrial and aquatic environments. The Iput River scenario was used by the Dose Reconstruction Working Group of the BIOMASS (Biosphere Modelling and Assessment Methods) programme. The test area was one of the most highly contaminated areas in Russia following the accident, with an average contamination density of 137Cs of 800,000 Bq m-2 and localized contamination up to 1,500,000 Bq m-2, and a variety of countermeasures that were implemented in the test area had to be considered in the modelling exercise. Difficulties encountered during the exercise included averaging of data to account for uneven contamination of the test area, simulating the downward migration and changes in bioavailability of 137Cs in soil, and modelling the effectiveness of countermeasures. The accuracy of model predictions is dependent at least in part on the experience and judgment of the participant in interpretation of input information, selection of parameter values, and treatment of uncertainties.