Human papillomavirus infection. Frequency and association with cervical neoplasia in a young population.

One million, six hundred thirty-two thousand, eight hundred forty-seven women from two independent populations in the United States received cytologic screening during a two-year period. Condylomatous lesions (human papillomavirus [HPV] infections) were the most frequent cytologic abnormality in women in both the Planned Parenthood and private sector groups (prevalence rates of 18.6 to 19.0 in women between ages 15 to 19). The prevalence rates of mild-to-moderate dysplasia were also similar in both populations, with the highest frequencies being between ages 25 to 29. Severe dysplasia and carcinoma in situ were most frequent between ages 35 to 39. In both populations, women with condylomatous changes coexisting with dysplastic changes were about ten years younger, grade-for-grade of severity of the lesion, than women without evidence of HPV infection. Since HPV infection is believed to represent the soil from which neoplasm develops, both the frequency of condyloma and the occurrence of dysplasia and cancer in young women suggest that women should begin regular screening programs while in their teens or after they become sexually active.

Observations and predictions of secondary neutrons on Space Shuttle and aircraft.

The Cosmic Radiation Effects and Activation Monitor has flown on six Shuttle flights between September 1991 and February 1995 covering the full range of inclinations as well as altitudes between 220 and 570 km, while a version has flown at supersonic altitudes on Concorde between 1988 and 1992 and at subsonic altitudes on a SAS Boeing 767 between May and August 1993. The Shuttle flights have included passive packages in addition to the active cosmic ray monitor which comprises an array of pin diodes. These are positioned at a number of locations to investigate the influence of shielding and local materials. Use of both metal activation foils and scintillator crystals enables neutron fluences to be inferred from the induced radioactivity which is observed on return to Earth. Supporting radiation transport calculations are performed to predict secondary neutron spectra and the energy deposition due to nuclear reactions in silicon pin diodes and the induced radioactivity in the various scintillator crystals. The wide variety of orbital and atmospheric locations enables investigation of the influence of shielding on cosmic ray, trapped proton and solar flare proton spectra.

Updated measurements from CREAM & CREDO & implications for environment & shielding models.

Flight data obtained between 1995 and 1997 from the Cosmic Radiation Environment Monitors CREAM & CREDO carried on UoSat-3, Space Shuttle, STRV-1a (Space Technology Research Vehicle) and APEX (Advanced Photovoltaic and Electronics Experiment Spacecraft) have been added to the dataset affording coverage since 1990. The modulation of cosmic rays and evolution of the South Atlantic Anomaly are observed, the former comprising a factor three increase at high latitudes and the latter a general increase accompanied by a westward drift. Comparison of particle fluxes and linear energy transfer spectra is made with improved environment & radiation transport calculations which account for shield distributions and secondary particles. While there is an encouraging convergence between predictions and observations, significant improvements are still required, particularly in the treatrnent of locally produced secondary particles.

Implications for space radiation environment models from CREAM & CREDO measurements over half a solar cycle.

Flight data obtained between 1990 and 1997 from the Cosmic Radiation Environment Monitors CREAM & CREDO carried on UoSAT-3, Space Shuttle, STRV-1a (Space Technology Research Vehicle) and APEX (Advanced Photovoltaic and Electronics Experiment Spacecraft) provide coverage over half a solar cycle. The modulation of cosmic rays and evolution of the South Atlantic Anomaly are observed, the former comprising a factor of three increase at high latitudes and the latter a general increase accompanied by a north-westward drift. Comparison of particle fluxes and linear energy transfer (LET) spectra is made with improved environment & radiation transport calculations which account for shield distributions and secondary particles. While there is an encouraging convergence between predictions and observations, significant improvements are still required, particularly in the treatment of locally produced secondary particles. Solar-particle events during this time period have LET spectra significantly below the October 1989 event which has been proposed as a worst case model.

Evaluation of the North Carolina Risk Reduction Program for smoking and alcohol.

Seventh grade students in two school systems in rural North Carolina were subjects for a program designed to reduce health risks associated with use/abuse of tobacco and alcohol. One school system was located in the central area of the state, and the other in the western mountains. Both groups were assessed before and after introduction of novel teaching programs dealing with alcohol and tobacco. Knowledge about smoking and alcohol increased in both sites (p less than .05). Attitudes toward alcohol did not change. Attitudes toward smoking eroded in both sites, with attitudes at one site showing a severe erosion (p less than .05). Smoking education in these communities may have conflicted strongly with ambient attitudes toward smoking, eliciting a "boomerang" effect.

Locus of control and smokeless tobacco use among adolescents.

Seventh-grade students from two school districts in rural North Carolina were surveyed to determine the prevalence and correlates of smokeless tobacco use. The survey was carried out as part of a larger project intended to study prevalence of "risky" behaviors, specifically alcohol and tobacco use. Data were collected from 322 students: 49% male, 36.6% nonwhite. Of those reporting use of smokeless tobacco (11.4%), virtually all were male; most reported weekly use, with a small proportion (1.3%) reporting daily use. Locus of control of "occasional" users was significantly more internal than those reporting "regular" use (p less than .05).

Prevalence of health-risk behavior among seventh grade students in North Carolina.

Data from 386 seventh grade students, 48% male and 65% white, were collected at two sites in North Carolina. The purpose of the study was to estimate the prevalence of alcohol and drug use among adolescents as part of a continuing study of preventive health behaviors. The data were collected anonymously from self-completed questionnaires and were analyzed by race and sex to determine knowledge of and attitudes toward alcohol and smoking, self-concept, and locus of control. Black boys had the highest prevalence of alcohol (16%) and tobacco (20%) use and at the same time had the lowest amount of knowledge about the dangers of the substances. White boys, while knowing more about the potential dangers, reported similar patterns of use. In general, girls used much less alcohol and tobacco and had higher levels of knowledge and more prudent attitudes. Boys, particularly blacks, were found to be at greater risk than girls of developing patterns of behavior that are associated with abuse of alcohol and heavy smoking. The findings suggest that health education to inform adolescents of the dangers of alcohol and smoking needs to be specific to cultural and sex groups.

Membrane recycling due to low and high rates of nerve stimulation at release sites in the amphibian (Bufo marinus) neuromuscular junction.

The activity-dependent labelling of motor nerve terminals with the dye FM1-43 has been used to estimate the relative levels of membrane recycling (due to synaptic vesicle exocytosis and recovery) at release sites in response to 1,200 nerve stimulations delivered at either low (0.5 Hz) or high (30 Hz) frequency. Dye in terminals appears as fluorescent spots distributed along the terminal branches; each spot is thought to be a cluster of labelled vesicles associated with a release site. Relative fluorescence in spots was quantified from images obtained with a confocal microscope. Spot intensities varied widely within branches following labelling at both frequencies, but the distribution was highly skewed towards lower intensities at low frequency stimulation; at high frequency, more spots had stronger fluorescence. Both weak and strongly stained spots were uniformly distributed along the length of terminal branches after low frequency stimulation; however, there was a gradual decline in all spot intensities towards the distal end of branches loaded with dye at high frequency stimulation. Antibody staining for synaptic vesicles was, on average, uniformly distributed along the branches. The increase in number of more strongly FM1-43-labelled spots in terminal branches stimulated at high compared with low frequency suggests that more release sites are active at high rates of nerve stimulation. This "recruitment" of release sites at high frequency stimulation occurs mostly in the proximal half of terminal branches and is not related to the abundance of synaptic vesicles in the terminal.