Geomicrobiology of subglacial ice above Lake Vostok, Antarctica.

Data from ice 3590 meters below Vostok Station indicate that the ice was accreted from liquid water associated with Lake Vostok. Microbes were observed at concentrations ranging from 2.8 x 10(3) to 3.6 x 10(4) cells per milliliter; no biological incorporation of selected organic substrates or bicarbonate was detected. Bacterial 16S ribosomal DNA genes revealed low diversity in the gene population. The phylotypes were closely related to extant members of the alpha- and beta-Proteobacteria and the Actinomycetes. Extrapolation of the data from accretion ice to Lake Vostok implies that Lake Vostok may support a microbial population, despite more than 10(6) years of isolation from the atmosphere.

Factors associated with breast implant rupture: pilot of a retrospective analysis.

This pilot study's goal was to test the feasibility of a data collection form which will be used in a scale-up study analyzing multiple surgeons' records. The goal of this expanded study will be to develop identifying factors for women who are at greater risk for having ruptured implants and, if necessary, target them for screening, surveillance, or intervention. In the pilot study, we compared factors associated with implant rupture in women with and without rupture. Similar studies have considered one or a few factors at a time and, generally, have given little attention to implant generation. We developed a data collection form after reviewing records of three surgeons. A total of 92 records was collected and analyzed. An important feature in the pilot was to compare the results of patients whose implants the surgeons had both implanted and explanted (n = 34) with those of patients whose implants the surgeons had only explanted (n = 55) (unknown = 3). This comparison could show if including all explantation patients in a surgeon's practice would bias the sample; however, based on this pilot data, concerns regarding this type of bias seem to be minimal. Similar amounts of data (e.g., implant information, history of capsular contracture, etc.) were collectable on patients whose surgeons both implanted and explanted them (87%) and who had different surgeons for implantation and explantation (84%). Though the data from this limited sample cannot offer firm conclusions on rupture associations, a few factors stood out: size of implants (38. 3% of ruptured versus 15.9% of intact implants were 100-200 cm3), history of mammography (46.8% of ruptured versus 24.4% of intact had mammograms, which is likely due to older women with older implants having more mammograms), and history of closed capsulotomy (85.1% of ruptured versus 68.9% of intact). Interestingly, additional procedures performed on the breast (e.g., scar revision, wound repair, etc.) did not affect rupture: both the ruptured and the intact groups had an average of 1.7 procedures performed. The data collection form tested very well in this pilot study. Also, including all patients in the study sample, instead of excluding those who received their implants elsewhere, did not change the results. Though there are not enough data to draw any firm conclusions regarding rupture factors, the collection instrument was rigorously tested and should perform well in an expanded study.

A review of the literature on the etiology of capsular contracture and a pilot study to determine the outcome of capsular contracture interventions.

The etiology of capsular contracture is unclear and probably multifactorial. This review covers the literature on several proposed contracture factors, including filler material, implant placement, surface texture, and bacterial infection. The pilot study's goal was to test the feasibility of a data collection form, which could be used in a scaled-up study analyzing multiple surgeon's records. The goal of the expanded version of this study will be to determine the efficacy of available interventions for capsular contracture, including surveillance. The Breast Implant Public Health Project, LLC (BIPHP), piloted a retrospective review of outcomes in women who had interventions to relieve capsular contracture or had chosen a wait-and-watch approach. An evaluation of the efficacy of various treatments can help women decide if they want to pursue treatment at all and, if so, which treatment might offer them the best solution. BIPHP researchers (E.E.A., M.E.) developed a data collection form after reviewing records of three surgeons (B.C., W.P., V.L.Y.). During the data collection using the same records, we tested a randomization process to identify women with capsular contracture who underwent various interventions, including a wait-and-watch strategy, and those who had no mention of any intervention or waiting approach. Data were gathered on a total of 90 breasts with capsular contracture (scored Baker I-IV or qualitatively), of which 45 underwent a total of 102 interventions for capsular contracture. Interventions were classified as "closed capsulotomy," "surgical," or "watchful waiting." Closed capsulotomy was performed most often (47%), followed by surgery (29%) and watchful waiting (21%). Presurgical Baker scores averaged higher in breasts that underwent surgery (3.1) than for watchful waiting (2.5) or closed capsulotomy (2.3). Though closed capsulotomies had 100% of outcomes scoring "improved" or "same," 58% of the breasts underwent the procedure more than once, suggesting that the favorable outcome was short-lived. The wait-and-watch approach resulted in scores of either "same" or "worse"; surgery (open capsulotomy, repositioning, or capsulectomy) resulted in 79% improved, 16% same, and 5% worse outcomes in breasts with outcomes listed. In all intervention procedure categories, outcomes were frequently unavailable; they were noted only 60% of the time (52/87). The missing 40% may have resulted from the doctor's failure to note it in the chart, satisfied patients not returning for additional treatment, or dissatisfied patients seeking treatment elsewhere. Generally, the data collection forms and procedures were workable; however, we uncovered issues to address in the scale-up of this pilot study: (1) the outcome report rate was 60%; (2) though Baker scores are commonly used to evaluate the degree of capsular contracture, it seems that grade I may have different meanings for different surgeons, which would need to be clarified; (3) participating surgeons will need to divulge standard-of-care items that they may not have included in medical records, but routinely performed (e.g., patient massage, use of prophylactic antibiotics); and (4) records were initially separated by "implant," then researchers realized that a more useful collection would be by "breast." The latter approach captures the history of the breast in one record, which may be more important to contracture than the differences in implants. With the modifications discussed, the study can be scaled up to encompass as many records as necessary to achieve robust statistical power. These data will add to the existing literature regarding factors associated with capsular contracture and identify factors that affect the successful outcome of capsular contracture interventions.

Cancer mortality among women employed in health care occupations in 24 U.S. states, 1984-1993.

BACKGROUND: Health care workers are potentially exposed to a number of carcinogens. Studies among women in this field have focused on white nurses; however, workers in many health care occupations share exposures experienced by nurses. METHODS: Cancer mortality was examined among female health care workers using death certificate data collected in 24 U.S. states from 1984 through 1993. Cancer mortality odds ratios (MORs) were calculated by race (white, black) and age group. RESULTS: White nurses had a 30% elevation of mortality due to liver cancer and myeloid leukemia. White registered nurses (RNs) had a small excess and white licensed practical nurses (LPNs) had a small deficit of mortality due to breast cancer. Ovarian cancer was in excess among RNs, but decreased among LPNs. Among black nurses, excesses of death due to kidney cancer (MOR = 1.7) and multiple myeloma (MOR = 1.3), and a significant 50% deficit in mortality due to cancer of the esophagus were found. Black RNs, but not LPNs, had an excess of breast cancer (MOR = 1.3; 95% CI = 1.0-1.5). Ovarian cancer was elevated by 30% in both RNs and LPNs. Excess deaths due to cancers of the breast, ovary, and uterus occurred among white physicians. Among black physicians, lung cancer was significantly elevated (MOR = 2.8). White pharmacists had significant excesses of breast (MOR = 1.5) and ovarian (MOR = 2.4) cancers, and myeloid leukemia (MOR = 2.0). White clinical laboratory technicians had excess deaths from several cancers. The greatest excess was for myeloid leukemia (MOR = 2.3; 95% CI = 1.5-3.4). Excesses among radiologic technologists included cancers of the lung, pancreas, breast, uterus, and ovary. CONCLUSION: Several findings reported here warrant further investigation. In particular, excesses of myeloid leukemia among nurses, pharmacists, and clinical laboratory technicians and liver cancer among nurses should be investigated in studies with data on occupational and other exposures. Patterns of mortality from breast and ovarian cancer found in this study must be evaluated further in studies with data on reproductive history.

Perennial Antarctic lake ice: an oasis for life in a polar desert.

The permanent ice covers of Antarctic lakes in the McMurdo Dry Valleys develop liquid water inclusions in response to solar heating of internal aeolian-derived sediments. The ice sediment particles serve as nutrient (inorganic and organic)-enriched microzones for the establishment of a physiologically and ecologically complex microbial consortium capable of contemporaneous photosynthesis, nitrogen fixation, and decomposition. The consortium is capable of physically and chemically establishing and modifying a relatively nutrient- and organic matter-enriched microbial "oasis" embedded in the lake ice cover.

Kinetic analysis of 5 alpha-reductase isoenzymes in benign prostatic hyperplasia (BPH).

Kinetic parameters (KM and Vmax) of the 5 alpha-reductase activities in homogenates of stroma and epithelium, isolated from BPH tissue, were determined using both testosterone and progesterone as substrate. The mean KM values for stromal 5 alpha-reductase, at 67.9 nM and 27.7 nM for testosterone and progesterone respectively, were 3-4-fold higher than the comparable KM estimates for the epithelial enzyme. The KM estimates for the epithelial 5 alpha-reductase showed little variation whereas those measured in the stromal homogenates could be subgrouped at less than 50 nM and greater than 100 nM. The mean Vmax for the stromal 5 alpha-reductase was approximately 235 pmol/30 min/mg protein irrespective of the substrate used; a value 10-fold higher than the Vmax of the epithelial 5 alpha-reductase. Preliminary experiments with inhibitors of 5 alpha-reductase demonstrated that the stromal and epithelial enzymes differed in their relative sensitivity to these compounds. Three major conclusions can be drawn from these results: first, that progesterone is a better substrate for prostatic 5 alpha-reductase than testosterone; second, that BPH tissue has at least two isoenzymes of 5 alpha-reductase--one in the epithelium and one (or more) in the stroma; and third, in hyperplastic prostates, most of the 5 alpha-reductase molecules are located in the stroma.

Survey of ocular cataracts in radium dial workers.

A survey of the medical records of 813 female radium dial workers first exposed to radium before 1930 yielded reports of 119 cataracts in the group whose radium body burden had been measured at least once. After dividing the subjects into high and low dose groups, the data were analyzed according to latency (time between first employment and first diagnosis of cataract), duration of employment and age at first exposure. Duration of employment and age at employment showed no significant correlation with dose. Latency, however, showed a significant negative correlation with dose. Since radiation cataracts tend to occur earlier than so-called senile cataracts, these preliminary data suggest the need for further investigation.

Breast cancer in female radium dial workers first employed before 1930.

Female radium dial workers first employed before 1930 were analyzed for breast cancer mortality and incidence using method and rate tables described by Monson and the Mantel-Haenszel summary chi-square test for significance. Of 1,180 located women, 736 were measured to estimate radium intake. This measured group was analyzed for breast cancer mortality and incidence according to four possible risk factors: radium intake dose, duration of employment, age at first exposure, and parity. The located women had a mortality ratio of 1.51 (p < 0.05). The measured women showed a significant excess of breast cancer incidence and mortality only among those women with a radium intake of 50 microCi or greater. Although the differences were not significant, incidence and mortality ratios were slightly higher for nulliparous women.