Biomedical subjects

P M Bracci

Publications and source records attributed to P M Bracci.

9 recordsLinked to original sources

PubMed2000

Pancreatic cancer and serum organochlorine levels.

Occupational exposure to p,p'-dichlorodiphenyltrichloroethane (DDT) has been associated with increased pancreatic cancer risk. We measured organochlorine levels in serum obtained at the study enrollment from 108 pancreatic cancer cases and 82 control subjects aged 32-85 years in the San Francisco Bay Area between 1996 and 1998. Cases were identified using rapid case-ascertainment methods; controls were frequency-matched to cases on age and sex via random digit dial and random sampling of Health Care Financing Administration lists. Serum organochlorine levels were adjusted for lipid content to account for variation in the lipid concentration in serum between subjects. Median concentrations of p,p'-dichlorodiphenyldichloroethylene (DDE, 1290 versus 1030 ng/g lipid; P = 0.05), polychlorinated biphenyls (PCBs; 330 versus 220 ng/g lipid; P<0.001), and transnonachlor (54 versus 28 ng/g lipid; P = 0.03) were significantly greater among cases than controls. A significant dose-response relationship was observed for total PCBs (P for trend <0.001). Subjects in the highest tertile of PCBs (> or =360 ng/g lipid) had an odds ratio (OR) of 4.2 [95% confidence interval (CI) = 1.8-9.4] compared to the lowest tertile. The OR of 2.1 for the highest level of p,p'-DDE (95% CI = 0.9-4.7) diminished (OR = 1.1; 95% CI = 0.4-2.8) when PCBs were included in the model. Because pancreatic cancer is characterized by cachexia, the impact of this on the serum organochlorine levels in cases is difficult to predict. One plausible effect of cachexia is bioconcentration of organochlorines in the diminished lipid pool, which would lead to a bias away from the null. To explore this, a sensitivity analysis was performed assuming a 10-40% bioconcentration of organochlorines in case samples. The OR associated with PCBs remained elevated under conditions of up to 25% bioconcentration.

Adult↗

PubMed1999

Case-control study of non-Hodgkin's lymphoma among women and heterosexual men in the San Francisco Bay Area, California.

A population-based case-control study was conducted between 1988 and 1995 in the San Francisco Bay Area of California to determine risk factors for non-Hodgkin's lymphoma. Participants completed in-person interviews, and blood was drawn to test for viruses and lymphocyte subsets. This report includes data for 1,281 cases and 2,095 controls. In multivariate analyses, the factors associated with a decreased risk for non-Hodgkin's lymphoma were allergy to plants, bee and wasp stings, five or more vaccinations, drugs to lower blood cholesterol, nonsteroidal anti-inflammatory drugs, total number of sexual partners, and lifetime marijuana use, whereas an increased risk was associated with cimetidine and other histamine H2-receptor antagonists, splenectomy, gonorrhea, and body mass index. Unique to sex-specific models was an increased risk for endocrine gland disorders among women and for polio among men. Median CD3, CD4, CD8, CD20, and lymphocyte counts for non-Hodgkin's lymphoma patients were significantly lower than those for controls. These results implicate environmental factors that may influence the early stages of lymphomagenesis by stimulating the immune system. Antigen-driven B cells that accumulate to form lymphoma may be suppressed by immunologic stresses such as exposure to an increased number of sexual partners and to certain medications. A history of allergies provides evidence for a persistent capacity for B-cell differentiation and therefore a decreased accumulation of B cells. The decreased risk for non-Hodgkin's lymphoma with use of nonsteroidal anti-inflammatory drugs and cholesterol-lowering drugs is consistent with a macrophage inflammatory role in B-cell proliferation.

Adult↗

PubMed1998

Hair-color products and risk for non-Hodgkin's lymphoma: a population-based study in the San Francisco bay area.

OBJECTIVES: As part of a large, epidemiologic study of non-Hodgkin's lymphoma, this study investigated a possible association between use of hair-color products and non-Hodgkin's lymphoma. METHODS: A population-based case-control study was conducted in the San Francisco Bay area. Of 4108 participants, 2544 were questioned about use of hair-color products. Control subjects were identified by use of random-digit dialing. RESULTS: Ever use of hair-color products was reported by 56% of case and 56% of control women and 10% of case and 9% of control men. Risks were not elevated for women for use of any hair-color products. Men who ever used semipermanent hair color had slightly elevated risks for non-Hodgkin's lymphoma, with trends associated with greater lifetime frequency of use and frequency of use per year, although individual confidence intervals overlapped unity. These elevated risks were diminished with exclusive use of semipermanent products, and confidence intervals overlapped unity. CONCLUSIONS: Integration of our results with those from experimental animal studies and other epidemiologic studies provides little convincing evidence linking non-Hodgkin's lymphoma with normal use of hair-color products in humans.

Adult↗

PubMed1998

Analysis of compositional bone density data using log ratio transformations.

In skeletal research, one of the techniques available to measure bone mineralization produces compositional data, which consist of vectors of ordered proportions of bone sample in prespecified density intervals. We investigated the value of two multivariate data transformations, the cumulative log ratio and the continuation log ratio, in the analysis of an experimental study of the dose-response effect of a drug treatment on bone mineralization. Based on a comparison of alternative approaches to the analysis of compositional bone mineralization data in the application and in a simulation study, we recommend the use of the average of the cumulative log ratios over all the density intervals to detect change in the density distribution. We also recommend the use of one of the continuation log ratios when a specific density interval of interest can be specified a priori.

Animals↗

PubMed1998

Farm and animal exposures and pediatric brain tumors: results from the United States West Coast Childhood Brain Tumor Study.

Nineteen counties from San Francisco and Los Angeles, California and Seattle, Washington were the United States sites for a large population-based case-control study of childhood brain tumors (CBTs), sponsored by the National Cancer Institute. CBT patients who were < 20 years of age and were diagnosed between 1984 and 1991 were reported to each region's cancer registry. The 801 control subjects were obtained by random digit dial and were frequency-matched to the 540 CBT patients in San Francisco and Seattle (one patient to two controls) and in Los Angeles (one patient to one control). Data collected by in-person interview with subjects' mothers were analyzed to investigate an association between risk for CBTs and life on a farm, exposure to farm animals (dairy cattle, beef cattle, pigs, sheep/goats, poultry, and horses), and some cat and non-farm horse exposures. Elevated risks for CBTs were observed in association with mothers' exposure to pigs [odds ratio (OR) = 3.8, 95% confidence interval (CI) = 1.2-12] and horses (OR = 2.2, 95% CI = 1.0-4.8) on a farm during the index pregnancy. Children diagnosed with primitive neuroectodermal tumors showed elevated risks for CBTs with personal and maternal prenatal exposure to pigs (child, OR = 4.0, 95% CI = 1.2-13; mother, OR = 11.9, 95% CI = 2.8-51) and poultry (child, OR = 3.0, 95% CI = 1.1-8.0; mother, OR = 4.0, 95% CI = 1.2-14). No other animal exposures of children or mothers were found to be consistently related to CBTs. Children diagnosed with primitive neuroectodermal tumors who were on a farm for > 1 year and were first on a farm when they were < 6 months of age also had increased risk for CBTs (OR = 3.9, 95% CI = 1.2-13). A somewhat increased risk for CBTs was found for children of mothers who ever had worked on livestock farms compared with mothers who never had worked on a farm (OR = 7.4, 95% CI = 0.86-64, based on five case mothers and one control mother who worked on livestock farms during the 5 years preceding the birth of the index child). The associations are consistent with those of two previous studies in Norway (P. Kristensen et al., Int. J. Cancer, 65: 39-50, 1996) and the United States and Canada (G. R. Bunin et al., Cancer Epidemiol. Biomark. Prev., 3: 197-204, 1994) that investigated the role of farm-related exposures in the etiology of CBTs.

Adolescent↗

PubMed1996

Neonatal intracranial ischemia and hemorrhage: diagnosis with US, CT, and MR imaging.

PURPOSE: To assess the usefulness of ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging in the detection of intracranial hemorrhage and ischemia in newborns. MATERIALS AND METHODS: Seventy-six neonates who underwent US within 72 hours of CT or MR examination were studied. Four observers rated images for the presence of germinal matrix hemorrhage (GMH), intraventricular hemorrhage (IPH), extraaxial hemorrhage, and hypoxic-ischemic encephalopathy. RESULTS: In 39% of neonates, CT and MR imaging provided greater confidence than US for the diagnosis or exlusion of neonatal ischemia or hemorrhage. Kappa analysis revealed significantly better interobserver agreement with CT than with US for the detection of GMH, IVH, IPH, and cortical infarction or ischemia (P <.005). Interobserver agreement was significantly better with MR imaging than with US for the detection of GMH, IVH, and cortical infarction or ischemia (P < .005). CONCLUSION: Sensitivity and interobserver agreement are better with MR imaging and CT than with US for the detection of neonatal cortical ischemia or infarction.

Apgar Score↗

PubMed1996

Prenatal exposure to tobacco smoke and childhood brain tumors: results from the United States West Coast childhood brain tumor study.

Data from a large, population-based case-control study were analyzed to investigate the relationship between prenatal exposure to tobacco smoke and childhood brain tumors (CBTs). A total of 540 CBT patients, diagnosed between 1984 and 1991, were identified from population-based tumor registries in 19 West Coast counties that included Seattle, WA (13 counties), San Francisco, CA (5 counties), and Los Angeles, CA (1 county). Random digit dial was used to select 801 control subjects from the three geographical regions to obtain a case:control ratio of 1:2 in San Francisco and Seattle and 1:1 in Los Angeles. The data first were analyzed separately by geographical site and then were combined with adjustments made for gender, age at the time of diagnosis (or reference date of control subjects), birth year of the index child, and maternal race. No association was found between the risk of CBTs and maternal or paternal smoking before pregnancy and there was no association between CBTs and maternal smoking during pregnancy [odds ratio (OR) = 0.98; 95% confidence interval (CI) = 0.72-1.3]. A slightly increased OR for CBTs was found for paternal smoking during pregnancy in the absence of maternal smoking (OR = 1.2; 95% CI = 0.90-1.5) and for maternal exposure to passive smoke from any source (OR = 1.2; 95% CI = 0.95-1.6). The results of this analysis are consistent with results from several prior epidemiological studies that showed no significant association between CBTs and maternal smoking before or during pregnancy or maternal exposure to passive smoke during pregnancy.

Adolescent↗

PubMed1995

Thrombolysis with tissue plasminogen activator (tPA) is temperature dependent.

Thrombolysis with tissue plasminogen activator (tPA) and hypothermia are two potential treatment modalities for acute ischemic stroke. Many investigators are studying these modalities both in the laboratory and in clinical trials. Because these modalities each appear to show benefit in animal models, there is considerable interest in studying combined therapy with both thrombolysis and hypothermia. However, it is known that alterations in the coagulation system can occur with decreased body temperature. Clinicians have frequently observed bleeding problems when patients are subjected to hypothermia for a variety of reasons. Hypothermia induced coagulopathy has been attributed to a variety of factors. Hypothermia can cause platelet dysfunction, inhibition of clotting factors, increased fibrinolysis and endogenous production of a heparin-like factor. Groups who studied fibrinolysis and temperature, however, found the opposite to be the case. Clot lysis studies with streptokinase showed increased fibrinolysis at higher temperatures. Data by Mumme suggested that the peak fibrinolytic activity of streptokinase was at 40 degrees C, but at 43 degrees C fibrinolytic activity was decreased. Rijken et al studied plasminogen activation with tissue plasminogen activator (tPA), urokinase and streptokinase at extremely low temperatures. They found less plasminogen activation and fibrinogen degradation at 25 degrees C compared to 37 degrees C, but negligible differences at 10 degrees C, 0 degrees C and -8 degrees C. To our knowledge, there is no data studying the fibrinolytic activity of tissue plasminogen activator (tPA) at temperature ranges between 25-37 degrees C which is the range of temperatures used clinically for therapeutic purposes.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1995

Circle of Willis: evaluation with spiral CT angiography, MR angiography, and conventional angiography.

PURPOSE: To evaluate the use of spiral computed tomographic (CT) angiography in the analysis of the arteries of the circle of Willis and compare these results with magnetic resonance (MR) angiography and conventional angiography. MATERIALS AND METHODS: The results in 17 patients who underwent examination were prospectively studied in a blinded fashion. The presence or absence of the arteries of the circle of Willis was determined by using maximum intensity projection reconstructions from CT angiography and MR angiography. These results were compared with results from conventional angiography. RESULTS: Similar sensitivities were determined for CT angiography (88.5%) and MR angiography (85.5%); however, MR angiography was found to differ significantly (P = .005) from conventional angiography. No significant differences (P > .05) were found between the two modalities and conventional angiography in the detection of the anterior, middle, or posterior cerebral arteries or the anterior communicating artery. CONCLUSION: Spiral CT angiography is highly sensitive in the detection of arterial anatomy in the circle of Willis and is a reliable alternative to MR angiography.

Cerebral Angiography↗