32P-postlabeling analysis of DNA adducts in human sperm cells from smokers and nonsmokers.

To determine the feasibility of using human sperm cells for DNA 32P-postlabeling analyses, and to evaluate the baseline level and the possible presence of smoking-related DNA adducts in these cells, sperm DNA was isolated from specimens obtained from 12 heavy smokers, 12 light smokers, and 12 nonsmokers. Background levels of radioactivity were minimized by using magnet transfer of 32P-labeled mononucleotides to new polyethyleneimine cellulose plates. Compared with placental tissues, few adducts were observed. Diffuse radioactivity observed in some of the autoradiograms was minimally above background but the level of radioactivity expressed as putative adducts/nucleotide was not related to smoking status. It was not clear, in some cases, whether this radioactivity was associated with chemically bound adducts or was from nonspecifically bound chemicals, radiolabeled enzymes, or other proteins. One major discrete DNA adduct of unknown chemical structure was detected in three of the 36 samples analyzed (one nonsmoker and two smokers). Based on the level of radioactivity associated with various dilutions of a benzo(a)pyrene-derived adduct, our limit of sensitivity was at least 1.2 adducts/10(9) nucleotides. Our study emphasizes the need to more clearly define the significance of background radioactivity associated with DNA adduct maps where the measured adduct levels approximate detection limits defined by visual observance of adduct spots. This point is particularly relevant given that the 32P-postlabeling procedures rely, in part, on visual verification of the presence of DNA adducts.

Cotinine concentrations in semen, urine, and blood of smokers and nonsmokers.

Cotinine levels in the semen, urine, and blood of 88 male smokers and nonsmokers, aged 18 to 35, were analyzed via radioimmunoassay. Detectable cotinine levels were found in all three body fluids, and cotinine levels in all three fluids were highly correlated. Cotinine levels in semen and blood were of similar magnitude; cotinine levels in urine were an order of magnitude or more higher. In all three fluids, cotinine levels increased with an increase in cigarette smoke exposure.

The use of hospital discharge data for public health surveillance of Guillain-Barré syndrome.

The sensitivity of passive reporting of Guillain-Barré syndrome (GBS) to the Vermont Department of Health from 1980 to 1985 was compared to that of computerized hospital discharge abstract data. Written hospital discharge summaries were reviewed for clinical data to validate the computerized abstracts. In all, 51 definite and probable cases of GBS were identified from hospital data during a period when only 4 cases (8%) had been reported to the health department through passive physician reporting. Based on the hospital data, the incidence of this syndrome in Vermont was 1.6/100,000 population/year. The incidence rate for males was 1.5 times that for females. No geographical or seasonal clustering of cases was found. These epidemiological features are consistent with previously published data on the syndrome and suggest that the incidence has not changed significantly in the past 10 years. Incidence rates for GBS based on passively reported cases markedly underestimate the true incidence rate. Although limited by the lack of timeliness for public health surveillance, computerized hospital discharge data are readily available in many states and may be more sensitive in detecting cases, compared to passive surveillance. They may be a useful tool for establishing baseline rates and examining long-term trends for selected acute diseases like GBS for which there are well-established diagnostic criteria and that usually result in hospitalization.

The surveillance of communicable disease in Vermont: who reports?

The Vermont Department of Health reviewed 2,035 reports of selected notifiable diseases received from January 1, 1986, through December 31, 1987. Laboratories provided 1,160, or 71 percent, of the initial reports on 1,636 confirmed cases. This demonstrates that laboratories, when required by law and when part of active surveillance, can make a significant contribution to surveillance of infectious disease. A survey of primary care physicians indicated that 18 percent always reported notifiable diseases. The most frequently mentioned reason for lack of reporting was an assumption that the laboratory would report the cases.

Association of heparan sulfate proteoglycan and laminin with the cytoskeleton in rat liver.

Rats were injected with 35SO4 and after 2 h their livers were removed and used to prepare a detergent-insoluble cytoskeleton fraction. Spectrin, cytokeratins, and actin were major protein components of the isolated cytoskeletons. The cytoskeleton fraction accounted for approximately 14% of the total trichloroacetic acid-insoluble 35SO4 radioactivity incorporated into the liver. The cytoskeleton-associated radioactivity was present in a single species of macromolecule. This molecule was not present to a significant extent in the detergent-soluble fraction containing the cell supernatant and dissolved membrane proteins. Further characterization revealed the cytoskeleton-associated molecule was a heparan sulfate proteoglycan: it was eluted from a Sepharose CL-4B column under denaturing conditions at Kav = 0.4; following mild alkaline hydrolysis the radioactivity was eluted at a Kav = 0.7; when this material was subjected to nitrous acid hydrolysis all of the radioactivity was eluted near the column included volume. The isolated cytoskeletons contained attached nuclei. Pure nuclei isolated without associated cytoskeletal elements contained less than 1% of the total liver trichloroacetic acid-insoluble 35SO4 radioactivity and no detectable heparan sulfate proteoglycan. These results suggested that other matrix proteins might be associated with the liver cytoskeleton. When the subcellular distribution of laminin was monitored by immunostaining proteins transferred to nitrocellulose, laminin was detected exclusively in the cytoskeleton fraction. These results provide evidence for an association between extracellular connective tissue proteins and intracellular structural proteins.

Comparison of methods to measure physical activity in postmenopausal women.

Five methods for assessing physical activity were evaluated in a population of 255 white, postmenopausal women participating in a randomized trial on the effects of walking on bone loss. Methods were the Paffenbarger survey, a modified Paffenbarger, the large-scale integrated activity monitor (LSI), caloric intake, and the Baecke survey. Significant increase in physical activity was observed in the intervention group. Activity measures were weakly related to each other. Results of factor analyses suggest that factor I reflected voluntary leisure-time pursuits (such as walking) and factor II, activities of daily living. Participation in sports was not a significant contributor to overall activity of the women. Research on physical activity must define the particular dimension of activity measured. Several types of instruments should be used because different instruments reflect different activity patterns which, in turn, may be differentially related to disease.

Lack of an association between calcium intake and blood pressure in postmenopausal women.

The cross sectional relationship between blood pressure and current calcium intake was examined in 199 white women aged 46-66 yr with no history of hypertension. Calcium intake was assessed from 3-day food logs and from elemental calcium composition of the reported calcium supplement. No significant correlation between calcium intake and blood pressure was detected even after controlling for other known risk factors for hypertension. In logistic regression analysis, the relative risk of having a systolic blood pressure greater than or equal to 130 mmHg, or a diastolic blood pressure greater than or equal to 90 mmHg according to calcium intake, was not significantly different from 1.0. These data suggest that dietary manipulation of calcium intake may not be beneficial in the prevention or treatment of hypertension in older women.

Postmenopausal bone density and milk consumption in childhood and adolescence.

Skeletal mass is a major determinant of susceptibility to osteoporotic fracture in menopause. At menopause, the skeletal mass is the resultant of the Peak Skeletal Mass (PSM) reached early adulthood minus the bone mass lost through the process of Adult Bone Loss (ABL). Current interventions for the maintenance of skeletal resilience in advanced age address the ABL peri- or postmenopausally. This study indicates that the effects of milk consumption in childhood and adolescence on bone density may manifest as higher bone density decades later in menopause. The assumed mechanism of the reported effect is through augmentation of the PSM, and acquisition of favorable nutritional habits which may influence the extent of ABL.

Pregnancy outcome in North American women. I. Effects of diet, cigarette smoking, and psychological stress on maternal weight gain.

This study examined the roles of diet, cigarette smoking, and psychological stress in pregnancy weight gain. The 60 were selected by defined criteria to minimize variation in anthropometric, socioeconomic, and medical variables which also affect weight gain. To maximize variation in weight gain, subjects were also selected on the basis of low weight gain (less than or equal to 15 lb) and adequate weight gain (greater than 15 lb). Each weight gain group contained smokers and nonsmokers. Smokers consumed more calories than nonsmokers (2119 versus 1810 kcal/day, p less than 0.01). for nonsmokers, differences between the intakes of low weight gain (1617 kcal/day) and adequate weight gain (1905 kcal/day) women were significant (p less than 0.02) and calorie intake was correlated with weight gain (r=0.44 p, less than 0.02). Psychological stress negatively correlated with weight gain (r=0.37, p less than 0.01) but not with calorie intake. We conclude that low weight gain is associated with a lower food intake. In contrast, smoking and stress may cause low weight gain by reducing the utilization of calories for weight gain.