Tuberculous sacroiliitis in a patient with systemic lupus erythematosus: a case report and literature review.

Systemic lupus erythematosus (SLE) patients are at higher risk of developing opportunistic infections such as tuberculosis (TB), especially extrapulmonary forms like osteoarticular TB, compared to the general population. However, tuberculous sacroiliitis has been scarcely reported in these patients. We present a 34-year-old woman with SLE who developed articular tuberculosis simultaneously affecting the right sacroiliac joint and the left knee. The patient was successfully treated with antituberculosis therapy for nine months. In this case, in addition to the immunological abnormalities of lupus, the long-term glucocorticoid therapy at high dosages was the main risk factor for the development of osteoarticular tuberculosis.

Correlated response in litter size components in rabbits selected for litter size variability.

A divergent selection experiment for the environmental variability of litter size (Ve) over seven generations was carried out in rabbits at the University Miguel Hernández of Elche. The Ve was estimated as the phenotypic variance within the female, after correcting for year-season and parity-lactation status. The aim of this study was to analyse the correlated responses to selection in litter size components. The ovulation rate (OR) and number of implanted embryos (IE) in females were measured by laparoscopy at 12 day of the second gestation. At the end of the second gestation, the total number of kits born was measured (TB). Embryonic (ES), foetal (FS) and prenatal (PS) survival were computed as IE/OR, TB/IE and TB/OR, respectively. A total of 405 laparoscopies were performed. Data were analysed using Bayesian methodology. The correlated response to selection for litter size environmental variability in terms of the litter size components was estimated as either genetic trends, estimated by computing the average estimated breeding values for each generation and each line, or the phenotypic differences between lines. The OR was similar in both lines. However, after seven generations of selection, the homogenous line showed more IE (1.09 embryos for genetic means and 1.23 embryos for phenotypic means) and higher ES than the heterogeneous one (0.07 for genetic means and 0.08 for phenotypic means). The probability of the phenotypic differences between lines being higher than zero (p) was 1.00 and .99, respectively. A higher uterine overcrowding of embryos in the homogeneous line did not penalize FS; as a result, this line continued to show a greater TB (1.01 kits for genetic means and 1.30 kits for phenotypic means, p = .99, in the seventh generation). In conclusion, a decrease in litter size variability showed a favourable effect on ES and led to a higher litter size at birth.

A candidate gene approach to searching for low-penetrance breast and prostate cancer genes.

Most cases of breast and prostate cancer are not associated with mutations in known high-penetrance genes, indicating the involvement of multiple low-penetrance risk alleles. Studies that have attempted to identify these genes have met with limited success. The National Cancer Institute Breast and Prostate Cancer Cohort Consortium--a pooled analysis of multiple large cohort studies with a total of more than 5,000 cases of breast cancer and 8,000 cases of prostate cancer--was therefore initiated. The goal of this consortium is to characterize variations in approximately 50 genes that mediate two pathways that are associated with these cancers--the steroid-hormone metabolism pathway and the insulin-like growth factor signalling pathway--and to associate these variations with cancer risk.

Prospective study of chemical exposures and amyotrophic lateral sclerosis.

BACKGROUND: Although environmental toxins, including pesticides, are suspected of contributing to the risk of amyotrophic lateral sclerosis (ALS), no data exist from large prospective investigations. This study assessed the association between exposure to chemicals and risk of ALS in a prospective cohort study. METHODS: The relation between self-report of regular exposure to 11 different chemical classes or x rays and ALS mortality among over 1 million participants in the American Cancer Society's Cancer Prevention Study II was prospectively assessed. Follow-up from 1989 through 2004 identified 617 deaths from ALS among men and 539 among women. Adjusted rate ratios (RR) were calculated using Cox proportional hazards. RESULTS: The RR for ALS mortality among individuals exposed to pesticides/herbicides compared with that among unexposed individuals was 1.07 (95% CI 0.79 to 1.44), but somewhat higher after excluding those with missing duration of pesticides exposure (RR 1.44; 95% CI 0.89 to 2.31; p = 0.14). A non-significant increase in ALS mortality was found among individuals who reported exposure to formaldehyde (RR 1.34; 95% CI 0.93 to 1.92). Excluding those with a missing duration of formaldehyde exposure, the RR was 2.47 (95% CI 1.58 to 3.86), and there was a strongly significant dose-response relation with increasing years of exposure (p trend = 0.0004). CONCLUSIONS: There was little evidence for any association between pesticides/herbicide exposure and ALS. In contrast, evidence was found, suggesting an increased risk of ALS with formaldehyde exposure. Because of the longitudinal design, this result is unlikely to be due to bias, but it should nevertheless be interpreted cautiously and needs to be verified independently.

Passive smoking exposure and female breast cancer mortality.

BACKGROUND: Several studies have reported positive associations between environmental tobacco smoke (ETS) and increased risk of breast cancer. However, studies of active smoking and risk of breast cancer are equivocal and in general do not support a positive association. To try to resolve this paradox, we examined the association between breast cancer mortality and potential ETS exposure from spousal smoking in an American Cancer Society prospective study of U.S. adult women. METHODS: We assessed breast cancer death rates in a cohort of 146 488 never-smoking, single-marriage women who were cancer free at enrollment in 1982. Breast cancer death rates among women whose husbands smoked were compared with those among women married to men who had never smoked. Cox proportional hazards modeling was used to control for potential risk factors other than ETS exposure. RESULTS: After 12 years of follow-up, 669 cases of fatal breast cancer were observed in the cohort. Overall, we saw no association between exposure to ETS and death from breast cancer (rate ratio [RR] = 1.0; 95% confidence interval [CI] = 0.8-1.2). We did, however, find a small, not statistically significant increased risk of breast cancer mortality among women who were married before age 20 years to smokers (RR = 1. 2; 95% CI = 0.8-1.8). CONCLUSIONS: In contrast to the results of previous studies, this study found no association between exposure to ETS and female breast cancer mortality. The results of our study are particularly compelling because of its prospective design as compared with most earlier studies, the relatively large number of exposed women with breast cancer deaths, and the reporting of exposure by the spouse rather than by proxy.

Cigarette smoking and colorectal cancer mortality in the cancer prevention study II.

BACKGROUND: Recent studies suggest that long-term cigarette smoking is associated with an increased risk of colorectal cancer. Whether the association is causal or due to confounding remains unclear. METHODS: We examined cigarette smoking in relation to colorectal cancer mortality, evaluating smoking duration and recency and controlling for potential confounders in the Cancer Prevention Study II. This prospective nationwide mortality study of 1 184 657 adults (age > or =30 years) was begun by the American Cancer Society in 1982. After exclusions, our analytic cohort included 312 332 men and 469 019 women, among whom 4432 colon or rectal cancer deaths occurred between 1982 and 1996 among individuals who were cancer free in 1982. Rate ratios (RRs) and 95% confidence intervals (CIs) were estimated by fitting Cox proportional hazards models. All statistical tests were two-sided. RESULTS: Multivariate-adjusted colorectal cancer mortality rates were highest among current smokers, were intermediate among former smokers, and were lowest in lifelong nonsmokers. The multivariate-adjusted RR (95% CI) for current compared with never smokers was 1.32 (1.16-1.49) among men and 1.41 (1.26-1.58) among women. Increased risk was evident after 20 or more years of smoking for men and women combined as compared with never smokers. Risk among current and former smokers increased with duration of smoking and average number of cigarettes smoked per day; risk in former smokers decreased significantly with years since quitting. If the multivariate-adjusted RR estimates in this study do, in fact, reflect causality, then approximately 12% of colorectal cancer deaths among both men and women in the general U.S. population in 1997 were attributable to smoking. CONCLUSIONS: Long-term cigarette smoking is associated with increased risk of colorectal cancer mortality in both men and women. Clear reduction in risk is observed with early smoking cessation.

Estrogen replacement therapy and risk of fatal colon cancer in a prospective cohort of postmenopausal women.

BACKGROUND: The results of several recent epidemiologic studies suggest that estrogen replacement therapy (ERT) in postmenopausal women may decrease their risk of subsequently developing colon or colorectal cancer. However, the association is not clear, as other similar studies have failed to show this inverse relationship. PURPOSE: The present study attempts a more definitive analysis of the relationship between fatal colon cancer and use of ERT among women in a large prospective study of adults in the United States. METHODS: Women were selected for study from the 676,526 female participants in Cancer Prevention Study II (CPS-II), a prospective mortality study of about 1.2 million American men and women (from all 50 states, the District of Columbia, and Puerto Rico), begun by the American Cancer Society in 1982. The median age of the female CPS-II participants was 56 years in 1982. Vital status was determined through December 31, 1989; 630,585 participants (93.2%) were still alive and 43,862 (6.5%) had died after 7 years of follow-up. Death certificates were obtained for 96.2% of participants known to have died. At the end of follow-up, 897 colon cancer deaths were observed in a cohort of 422,373 postmenopausal women who were cancer free at study entry. Cox proportional hazards modeling was used to compute rate ratios (RRs) and to adjust for other potential risk factors. The likelihood ratio test (two-sided) was used to determine the statistical significance of the interaction terms. RESULTS: Ever use of ERT was associated with significantly decreased risk of fatal colon cancer (RR = 0.71; 95% confidence interval [CI] = 0.61-0.83). The reduction in risk was strongest among current users (RR = 0.55; 95% CI = 0.40-0.76), and there was a significant (P = .0001) trend of decreasing risk with increasing years of use among all users: Users of 1 year or less had an RR of 0.81 (95% CI = 0.63-1.03), while users of 11 years or more had an RR of 0.54 (95% CI = 0.39-0.76). These associations were not altered in multivariate analyses controlling for other risk factors. CONCLUSIONS: In our data, estrogen therapy, particularly recent and long-term use, was associated with a substantial decrease in risk of fatal colon cancer. These results were consistent with several published studies suggesting a protective role of exogenous estrogens in the development of colorectal cancer and merit further investigation.

Cigarette smoking and changes in the histopathology of lung cancer.

BACKGROUND: Adenocarcinoma of the lung, once considered minimally related to cigarette smoking, has become the most common type of lung cancer in the United States. The increased incidence of this cancer might be explained by advances in diagnostic technology (i.e., increased ability to perform biopsies on tumors in smaller, more distal airways), changes in cigarette design (e.g., the adoption of filtertips), or changes in smoking practices. We examined data from the Connecticut Tumor Registry and two American Cancer Society studies to explore these possibilities. METHODS: Connecticut Tumor Registry data from 1959 through 1991 were analyzed to determine whether the increase in lung adenocarcinoma observed during that period could be best described by birth cohort effects (i.e., generational changes in cigarette smoking) or calendar period effects (i.e., diagnostic advances). Associations between cigarette smoking and death from specific types of lung cancer during the first 2 years of follow-up in Cancer Prevention Study I (CPS-I), initiated in 1959) and Cancer Prevention Study II (CPS-II, initiated in 1982) were also examined. RESULTS: Adenocarcinoma incidence in Connecticut increased nearly 17-fold in women and nearly 10-fold in men from 1959 through 1991. The increases followed a clear birth cohort pattern, paralleling gender and generational changes in smoking more than diagnostic advances. Cigarette smoking became more strongly associated with death from lung adenocarcinoma in CPS-II compared with CPS-I, with relative risks of 19.0 (95% confidence interval [CI] = 8.3-47.7) for men and 8.1 (95% CI = 4.5-14.6) for women in CPS-II and 4.6 (95% CI = 1.7-12.6) for men and 1.5 (0.3-7.7) for women in CPS-I. CONCLUSIONS: The increase in lung adenocarcinoma since the 1950s is more consistent with changes in smoking behavior and cigarette design than with diagnostic advances.

Risk factors for fatal colon cancer in a large prospective study.

BACKGROUND: Diet, physical activity, obesity, aspirin use, and family history may all modify the risk of colon cancer, but few epidemiologic studies are large enough to examine these factors simultaneously. PURPOSE: We prospectively assessed the relationship of diet and other factors to risk of fatal colon cancer. METHODS: Using data from Cancer Prevention Study II--an ongoing prospective mortality study--we studied 764,343 adults who, in 1982, completed a questionnaire on diet and other risk factors and did not report cancer or other major illness. We assessed mortality through August 1988 and identified 1150 deaths from colon cancer (611 men and 539 women). Multivariate analyses were used to compare these case patients with 5746 matched control subjects drawn from the cohort. RESULTS: Risk of fatal colon cancer decreased with more frequent consumption of vegetables and high-fiber grains (P for trend = .031 in men and .0012 in women). The relative risk (RR) for the highest versus lowest quintile of vegetable intake was 0.76 in men (95% confidence interval [CI] = 0.57-1.02) and 0.62 in women (95% CI = 0.45-0.86). Dietary consumption of vegetables and grains and regular use of aspirin were the only factors having an independent and statistically significant association with fatal colon cancer. Participants who consumed the least vegetables and grains and no aspirin had a higher risk compared with those who consumed the most vegetables and used aspirin 16 or more times per month. For men in the former category, the RR was 2.4 (95% CI = 1.1-5.3); for women, it was 2.9 (95% CI = 1.3-6.7). Weaker associations were seen for physical inactivity, obesity, total dietary fat, and family history. No associations were seen with consumption of red meat or total or saturated fat in either sex, but this finding must be interpreted cautiously. CONCLUSIONS: These findings support recommendations that increased consumption of vegetables and grains may reduce the risk of fatal colon cancer. Regular use of low doses of aspirin may prove to be an important supplemental measure.

Hair dye use and risk of fatal cancers in U.S. women.

BACKGROUND: Permanent hair dyes are used by about one third of adult American women. Several epidemiologic studies associate hair dye use with increased risk of non-Hodgkin's lymphoma and multiple myeloma. In one study, risk increased with more prolonged exposure to darker, more concentrated, permanent dyes. PURPOSE: The purpose of our study was to examine the relationship between hair dye use and development of certain cancers associated with hair dye use in previous studies. METHODS: We examined prospectively the relationship between the use of permanent hair dyes and selected fatal cancers in 573,369 women. The participants provided information in 1982 on the frequency and duration of hair dye use and the color of hair dye used. Death rates were measured through 1989. Relative risks (RRs) were computed with subjects who had not used hair dyes serving as the referent group, and 95% confidence intervals (CIs) were calculated on the basis of approximate-variance formulas. RESULTS: Women who had ever used permanent hair dyes showed decreased risk of all fatal cancers combined (RR = 0.93; 95% CI = 0.89-0.98) and of urinary system cancers (RR = 0.65; 95% CI = 0.49-0.87) and no increase in risk of any type of hematopoietic cancer. Women who had used black hair dyes for 20 years (0.6% of women hair dyers) or more had increased risk of fatal non-Hodgkin's lymphoma (RR = 4.37; 95% CI = 1.3-15.2) and multiple myeloma (RR = 4.39; 95% CI = 1.1-18.3). These positive findings are based on three cases of non-Hodgkin's lymphoma and two cases of multiple myeloma. We found no relationship between use of permanent hair dyes and fatal cancers of the mouth, breast, lung, bladder, or cervix, areas that were of interest as the result of earlier studies. CONCLUSIONS: Women using permanent hair dyes are not generally at increased risk of fatal cancer. Women with prolonged use of dark, particularly black, hair dyes may have increased risk of fatal non-Hodgkin's lymphoma and multiple myeloma, but these women are a small fraction of hair dye users. Nonetheless, the removal of carcinogens from hair dyes and appropriate labeling of hair-coloring products would help reduce this potential risk.

Aspirin use and risk of fatal cancer.

Aspirin and other nonsteroidal antiinflammatory drugs inhibit prostaglandin synthesis and tumor growth in many experimental systems, but it is unclear which of these tumor models are relevant to humans. We have reported reduced risk of fatal colon cancer among persons who used aspirin in a large prospective study. This analysis examines other fatal cancers in relation to aspirin among 635,031 adults in that study who provided information in 1982 on the frequency and duration of their aspirin use and did not report cancer. Death rates were measured through 1988. Death rates decreased with more frequent aspirin use for cancers of the esophagus, stomach, colon, and rectum but not generally for other cancers. For each digestive tract cancer, death rates were approximately 40% lower among persons who used aspirin 16 times/month or more for at least 1 year compared to those who used no aspirin. The trend of decreasing risk with more frequent aspirin use was strongest among persons who had used aspirin for 10 years or more; it remained statistically significant, except for esophageal cancer, in multivariate analyses that adjusted for other known risk factors. Biases such as early detection or aspirin avoidance among cases do not appear to explain the results. Our data suggest that regular, prolonged use of aspirin may reduce the risk of fatal cancer of the esophagus, stomach, colon, and rectum. Future epidemiological and basic research should examine all digestive tract cancers in considering the chemopreventive or therapeutic potential of nonsteroidal antiinflammatory drugs.

Necrosis of schwann cells during tellurium-induced primary demyelination: DNA fragmentation, reorganization of splicing machinery, and formation of intranuclear rods of actin.

We present a cytological, immunocytochemical, and biochemical study of the cell death of mature myelinating Schwann cells (SCs) in the primary demyelinating neuropathy induced by tellurium (Te). Weaned rats were fed a diet containing 1.1% elemental Te. The animals were killed daily within the first week of Te diet. After 4 to 6 days of Te treatment some SCs underwent degeneration and necrosis. By electron microscopy analysis, degenerating SCs showed chromatin condensation, detachment from the nuclear envelope of condensed chromatin clumps, aggregation of interchromatin granule clusters, formation of intranuclear bundles of microfilaments, and cytoplasmic vesiculation. By confocal laser fluorescence microscopy, chromatin regions were stained with the TUNEL method for in situ labeling of DNA fragmentation and exhibited a progressive reduction of histone signal. In addition, splicing small nuclear ribonucleoprotein (snRNP) factors were redistributed in a few large nuclear domains and bright foci of intranuclear actin were observed. DNA electrophoresis revealed a smear pattern of DNA fragmentation in sciatic nerve samples from Te-treated animals. Upon Te treatment, no degradation of the caspase substrates poly (ADP-ribose) polymerase and lamin B was detected by Western blots or immunocytochemistry, respectively. The peculiar structural rearrangement of the transcription and splicing machinery as well as the vesicular degeneration of the cytoplasm in degenerating SCs support an autophagic cell death of the necrotic type. Unlike the apoptosis of pre-remyelinating SCs (11), this caspase independent cell death of necrotic type involves mature pre-demyelinating SCs and eliminates SCs injured by the neurotoxic effect of Te.

Body mass index, height, and prostate cancer mortality in two large cohorts of adult men in the United States.

Body weight and height have both been associated consistently with postmenopausal breast cancer but less consistently with prostate cancer. The present study examined the relationship between body mass index (BMI), height, and death from prostate cancer in two large American Cancer Society cohorts. Men in the study were selected from the male participants in Cancer Prevention Study I (CPS-I; enrolled in 1959 and followed through 1972) and Cancer Prevention Study II (CPS-II; enrolled in 1982 and followed through 1996). After exclusions, 1,590 prostate cancer deaths remained among 381,638 men in CPS-I and 3,622 deaths among 434,630 men in CPS-II. Cox proportional hazards modeling was used to compute rate ratios (RR) and to adjust for confounders. Prostate cancer mortality rates were significantly higher among obese (BMI, > or =30) than nonobese (BMI, <25) men in both cohorts [adjusted RR, 1.27; 95% confidence interval (CI), 1.04-1.56 in CPS-I; RR, 1.21; 95% CI, 1.07-1.37 in CPS-II]. Prostate cancer mortality rates in the CPS-I cohort were lowest for the shortest men (RR, 0.80; 95% CI, 0.63-1.03 for men <65 inches versus 65-66 inches) and highest for the tallest men (RR, 1.39; 95% CI, 1.11-1.74 for men > or =73 inches tall versus 65-66 inches). Rates remained constant among men 65-72 inches tall. No association between height and prostate cancer mortality was observed in the CPS-II cohort (RR, 1.03; 95% CI, 0.82-1.29 for men > or =75 versus 65-66 inches). These results support the hypothesis that obesity increases risk of prostate cancer mortality. Decreased survival among obese men may be a likely explanation for this association.

A prospective study of diet and stomach cancer mortality in United States men and women.

Frequent consumption of fruits, vegetables, and whole grains has been associated with a reduced risk of stomach cancer in the majority of case-control studies of these factors: however, prospective studies have been less consistent. We examined the association between selected major food groups (citrus fruits, vegetables, whole grains, and processed meats) and risk of fatal stomach cancer in the Cancer Prevention Study (CPS) II cohort of 1.2 million United States men and women. During 14 years of follow-up, we documented 439 stomach cancer deaths in women and 910 in men after exclusion of individuals with prevalent cancers, inadequate diet information, and recent weight loss at baseline in 1982. After controlling for other risk factors, none of the food groups examined were associated with risk of stomach cancer except for an unexpected increased risk with vegetable consumption in women [relative risk (RR) = 1.25; 95% confidence interval (CI), 0.99-1.58; highest versus lowest tertile, P = 0.06 for trend]. A high overall plant food intake (a sum of vegetables, citrus fruit, and whole grains) was associated with reduced risk in men (RR = 0.79; 95% CI, 0.67-0.93; highest versus lowest tertile, P = 0.003 for trend), but not in women (RR = 1.18; 95% CI, 0.93-1.50; P = 0.16 for trend). Of individual foods examined, liver consumption greater than twice/week was associated with an increased risk of fatal stomach cancer in women (RR = 1.96; 95% CI, 1.09-3.53) and men (RR = 1.63; 95% CI, 1.02-2.62) compared with nonconsumers. This study supports a modest role for plant foods in reducing the risk of fatal stomach cancer in men, but not in women.

Vitamin C and vitamin E supplement use and colorectal cancer mortality in a large American Cancer Society cohort.

Some recent epidemiological studies have suggested that use of vitamin C or vitamin E supplements, both of which are important antioxidants, may substantially reduce the risk of colon or colorectal cancer. We examined the association between colorectal cancer mortality and use of individual vitamin C and E supplements in the American Cancer Society's Cancer Prevention Study II cohort. We used proportional hazards modeling to estimate rate ratios among 711,891 men and women in the United States who completed a self-administered questionnaire at study enrollment in 1982, had no history of cancer, and were followed for mortality through 1996. During the 14 years of follow-up, 4404 deaths from colorectal cancer occurred. After adjustment for multiple colorectal cancer risk factors, regular use of vitamin C or E supplements, even long-term use, was not associated with colorectal cancer mortality. The combined-sex rate ratios were 0.89 [95% confidence interval (CI), 0.73-1.09] for 10 or more years of vitamin C use and 1.08 (95% CI, 0.85-1.38) for 10 or more years of vitamin E use. In subgroup analyses, use of vitamin C supplements for 10 or more years was associated with decreased risk of colorectal cancer mortality before age 65 years (rate ratio = 0.48; 95% CI, 0.28-0.81) and decreased risk of rectal cancer mortality at any age (rate ratio = 0.40; 95% CI, 0.20-0.80). Our results do not support a substantial effect of vitamin C or E supplement use on overall colorectal cancer mortality.

Determinants of DNA yield and quality from buccal cell samples collected with mouthwash.

Buccal cells are becoming an important source of genomic DNA in epidemiological studies, but little is known about the effect of different sampling conditions on DNA quality and yield. We used a mouthwash protocol to collect six daily buccal cell samples from 35 healthy volunteers. Twenty-four individuals (six men and 18 women) correctly completed the protocol and were included in paired analyses to determine whether "swish" time (30 s versus 60 s), toothbrushing before collection, or lag time between collection and DNA extraction (1 day versus 5, 10, or 30 days at room temperature) would affect sample quality and yield. Total DNA, human-specific DNA (hDNA), degradation of DNA, and ability to amplify by PCR were determined. hDNA yield did not significantly vary by "swish" time. However, toothbrushing 1 h before sample collection reduced the amount of hDNA by nearly 40% (34 microg versus 21 microg; P = 0.06). Median hDNA yields for samples that were held for 1, 5, 10, and 30 days before extraction were 32 microg (range, 4-196), 32 microg (2-194), 23 microg (3-80), and 21 microg (5-56), respectively. The 10- and 30-day samples had significantly less hDNA than those processed after 1 day (P = 0.01). PCR success rates for beta-globin gene fragments of length 268 bp, 536 bp, and 989 bp were 94% or better, and high molecular weight DNA (>23 kb) was found in all but one sample. These results suggest that buccal cells should be collected before brushing teeth and processed within 5 days of collection to maximize hDNA yield.

Ligand binding to transmembrane receptors on intact cells or membrane vesicles measured in a homogeneous 1-microliter assay format.

We have developed homogeneous miniaturized assays to measure ligand binding to either intact cells or receptor-containing membrane fragments by analysis of particle brightness. As an example, the affinities and inhibition constants of fluorescently labeled interleukin-8 (IL-8) and a low-molecular-weight antagonist toward the receptors CXCR1 and CXCR2, which belong to the superfamily of G protein-coupled receptors (GPCRs), were determined. Although the results were generally comparable between the two approaches, the cell-based measurements revealed a more complex pattern of both ligand and inhibitor titration curves, pointing to the influence of intracellular regulatory events. Both the vesicle- and cell-based membrane receptor assays were successfully miniaturized to a total volume of 1 microl without compromising their sensitivity, indicating that screening of transmembrane receptors in these formats is feasible. This is the first report of a cellular ligand-binding assay performed in such low volumes. The resulting savings in reagent could potentially enable the use of primary cells for future HTS/ultra-HTS efforts.

A novel and robust homogeneous fluorescence-based assay using nanoparticles for pharmaceutical screening and diagnostics.

We have established a new type of homogeneous immunoassay based on nanoparticles (nanoparticle immunoassay, or NPIA) being analyzed using fluorescence intensity distribution analysis (FIDA). This method allows the characterization of single fluorescently labeled molecules or particles with respect to their molecular brightness and concentration. Upon binding of conjugates to molecules coupled to the nanoparticle surface, the brightness of the complex scales with the number of bound conjugates. The complexes can then be distinguished accurately from free conjugate and concentrations of free and bound molecules can be determined reliably. In this study we present various examples of NPIAs where capture antibodies were linked to the nanoparticles, which were either artificial beads or bacteria. Two assay formats have been developed; first, direct labeling of the conjugate was used to quantitate free antigen through competition experiments, and second, an antigen-directed antibody was labeled to establish an assay similar to a sandwich ELISA setup. The major advantages of a NPIA are the robustness and high signal-to-noise ratio at short measurement times, as demonstrated with a miniaturized experiment in a Nanocarriertrade mark holding a volume of 1 microl/well. In addition to the good data quality, NPIAs are straightforward to perform because they require no washing steps. NPIAs open new dimensions for high throughput pharmaceutical screening and diagnostics. Assay development times can be reduced significantly because of a simple toolbox principle that is applicable to most types of assays.

Recurrence of low birth weight in siblings.

The recurrence of low birth weight (LBW, less than 2500 g) in full siblings was studied in 3286 singleton infants born between 1966 and 1986 to 1677 male U.S. Army veterans who were part of a nationwide health study. Hospital of birth medical records were abstracted for these children. Mean birth weights, risks of LBW, LBW occurring with preterm delivery (less than 37 weeks) (LBW/p), and LBW in term infants (LBW/t) were examined in successive singleton siblings according to LBW status of prior siblings. The risk of LBW in infants who had prior siblings with LBW was 9.9%, compared with a risk of 2.8% in infants who had prior siblings without LBW (OR = 3.8, 95% CI 2.0-7.3). The excess recurrence of LBW was specifically due to LBW/p. Infants with prior siblings with LBW/p were at high tisk of LBW/p (OR = 9.2, CI 4.4-19.6) but not of LBW/t (OR = 2.0, CI 0.1-9.1). Using modified logistic regression techniques that incorporate familial risks and the effects of other risk factors, the excess sibling recurrence risk of LBW and LBW/p could not be explained by the tendency for recurrence in siblings of other risk factors for LBW, such as pregnancy complications, maternal illnesses, and birth defects. Although the familial factors involved in LBW may or may not be genetic in nature, such factors need to be investigated in epidemiologic studies of LBW and prematurity.

Cigarette smoking and diabetes mellitus: evidence of a positive association from a large prospective cohort study.

OBJECTIVE: Only a few prospective studies have examined the relationship between the frequency of cigarette smoking and the incidence of diabetes mellitus. The purpose of this study was to determine whether greater frequency of cigarette smoking accelerated the development of diabetes mellitus, and whether quitting reversed the effect. METHODS: Data were collected in the Cancer Prevention Study I, a prospective cohort study conducted from 1959 through 1972 by the American Cancer Society where volunteers recruited more than one million acquaintances in 25 US states. From these over one million original participants, 275,190 men and 434,637 women aged > or = 30 years were selected for the primary analysis using predetermined criteria. RESULTS: As smoking increased, the rate of diabetes increased for both men and women. Among those who smoked > or = 2 packs per day at baseline, men had a 45% higher diabetes rate than men who had never smoked; the comparable increase for women was 74%. Quitting smoking reduced the rate of diabetes to that of non-smokers after 5 years in women and after 10 years in men. CONCLUSIONS: A dose-response relationship seems likely between smoking and incidence of diabetes. Smokers who quit may derive substantial benefit from doing so. Confirmation of these observations is needed through additional epidemiological and biological research.