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Biomedical subjects

P Boyle

Publications and source records attributed to P Boyle.

At least 91 records · Page 5Linked to original sources

Recombinant human interleukin-11 prevents mucosal atrophy and bowel shortening in the defunctionalized intestine.

BACKGROUND: Mucosal atrophy and bowel shortening are the hallmark of proximal intestinal diversion for extensive necrotizing enterocolitis (NEC) or Thiry-Vella fistulas (TVF), in which the ends of a defunctionalized loop of intestine are exteriorized as stomas. Recombinant human interleukin-11 (rhIL-11) is a pleiotropic cytokine that promotes epithelial regeneration and enhances adaptation after bowel resection. The authors hypothesized that rhIL-11 may prevent mucosal atrophy and bowel shortening in rats with TVF METHODS: After creation of ileal TVF, Sprague-Dawley rats were selected randomly to receive either rhIL-11 or equal volume of 0.1% bovine serum albumin (BSA) subcutaneously daily. On day 14, the TVF were excised and examined morphologically. Enterocyte apoptosis was measured using the TUNEL assay. Mucosal DNA and protein content were measured. RESULTS: Administration of rhIL-11 resulted in a significantly greater weight gain and less shortening of TVF than BSA treatment. TVF from the rhIL-11-treated group showed evidence of hyperplasia and hypertrophy and increased crypt to villus ratio. The BSA group had substantial mucosal atrophy. There was a qualitative decrease in the incidence of apoptosis in the rhIL-11 group. CONCLUSIONS: Recombinant human IL-11 prevents mucosal atrophy and shortening of defunctionalized intestinal loops. It may help reduce the incidence of short gut syndrome in infants with extensive NEC.

Animals↗

Mortality from cutaneous melanoma: evidence for contrasting trends between populations.

In recent years several reports have been published concerning trends in melanoma mortality in different countries, some of which have indicated that rates are beginning to fall. Many of these reports, however, have been based on small populations and have used different forms of statistical analysis. Our objective was to analyse systematically to what degree the epidemic of melanoma mortality had evolved similarly in different populations and whether there were any divergent trends that might increase our understanding. Instead of using all available data, we focused on countries with a minimum time series of 30 years and a minimum of 100 deaths annually in at least one sex from melanoma. We first inspected sex-specific age-standardized mortality rates and then performed age-period-cohort modelling. We found that the increase in mortality observed after 1950 was more pronounced in the age group 60-79. Statistical modelling showed a general increase in mortality rates in generations born after the turn of the century. Downturns in mortality, essentially in women and starting with generations born just before World War II, were found in Australia (where the earliest decreases were noted), the Nordic countries and the USA. Small decreases in rates in more recent generations were found in the UK and Canada. However, in France, Italy and Czechoslovakia, mortality rates were seen to be still increasing in recent cohorts. Our analysis suggests that populations are at different places on the melanoma mortality epidemic curve. The three trend patterns we observed are in agreement with time differences between populations with respect to the promotion of sun protection and the surveillance of pigmented skin lesions.

Adult↗

Transcellular transport is not required for transmucosal bacterial passage across the intestinal membrane ex vivo.

The mechanisms underlying the process of bacterial translocation are poorly defined. Possible routes for transmucosal passage of bacteria include transcellular and paracellular channels. Bacterial engulfment is a prerequisite for transcellular transport. To determine whether transcellular transport is required for transmucosal bacterial passage, we examined the effect of various inhibitors of endocytosis, such as colchicine, cytochalasin B, and sodium fluoride on transmucosal passage of bacteria across an ileal mucosal membrane mounted in the Ussing chamber. Colchicine and sodium fluoride increased the rate of decline of the potential difference across the membranes. However, neither colchicine, cytochalasin B, nor sodium fluoride affected the incidence of transmucosal bacterial passage. Sodium fluoride, which depletes intracellular ATP, significantly decreased the number of bacteria that passed per membrane. Our data suggest that transcellular transport may not be required for spontaneous transmucosal passage of bacteria, and furthermore bacterial passage may be, at least in part, an energy-dependent process.

Animals↗

Sleep disturbances and their correlates in elderly Japanese American men residing in Hawaii.

BACKGROUND: Elderly people frequently report the presence of chronically disturbed sleep. However, most data are derived from predominantly Caucasian populations. The current study is an investigation of the prevalence and correlates of sleep disturbances in a cohort of elderly Japanese American men residing in Hawaii. The importance of this population lies in its representation of an ethnic group living in a culture different from their ancestry. METHODS: This study is a cross-sectional cohort analysis of data pertaining to sleep disturbances and their potential correlates from 3,845 elderly Japanese American men residing in Hawaii (mean age. 78 years; range, 71-93 years) who participated in the fourth survey of the Honolulu Heart Program (1991-1994), which is the baseline exam for the Honolulu-Asia Aging Study. Information collected included an extensive survey of medication use, medical history, and assessments of physical and mental function, quality of life, and sleep. RESULTS: The prevalence of insomnia (DIMS) was 32.6%, a rate similar to that reported in predominantly Caucasian populations. Depression, benzodiazepine use, and several chronic health problems were the most important factors associated with DIMS. In contrast, excessive daytime sleepiness (EDS) had a prevalence of 8.9%, a rate lower than that found in elderly Caucasian populations but close to that reported among native Japanese. Important factors related to EDS were symptoms of nocturnal respiratory disturbance, depression, perception of adverse quality of life, Parkinson's disease, and digitalis use. CONCLUSIONS: Elderly Japanese men are less likely than elderly Caucasian men to report excessive daytime sleepiness. However, their insomnia rates are similar.

Aged↗

Breast cancer incidence rates in Slovenia 1971-1993.

BACKGROUND: Analyses of time trends in breast cancer incidence and mortality have generally revealed cohort-based changes in the rates. These have been linked to cohort-based changes in lifestyle factors. The effect of the changes in the reproductive risk factors on the changes in the rates, and the relative importance of the reproductive characteristics in Slovenia, a country which has not had much breast cancer screening, are investigated. METHODS: Data on breast cancer incidence for 1971-1993 were obtained from the Cancer Registry of Slovenia (Registry). The Registry covers the whole population of the Republic of Slovenia (1.99 million on 30 June 1993). The statistical analysis uses parametric age-period-cohort models. RESULTS: Breast cancer incidence has increased by 70% in Slovenia from 1971 to 1993, These changes are dominated by cohort effects and the cohorts born in 1907-1922 have the greatest increase in incidence. Period effects on changes in incidence were modest. The percentage of nulliparous women in the cohort and the average family size in the cohort explained 38% of the variation in the cohort effects. CONCLUSIONS: The percentage of nulliparous women in the cohort is the most important reproductive variable associated with the trends in the rates, with breast cancer risk predicted to be higher in cohorts with a larger percentage of nulliparous women. As the cohorts born 1932-1946 have a more favourable reproductive pattern as regards breast cancer risk, compared to the 1907-1922 cohorts, age-specific incidence rates in Slovenia would be predicted to decline in the future in the absence of changes in the other risk factors.

Adult↗

Joint effects of nine polychlorinated biphenyl (PCB) congeners on breast cancer risk.

BACKGROUND: Polychlorinated biphenyls (PCB) have been a major environmental health concern because of their wide distribution and persistence in the environment. Estimating joint effects of all congeners in a single analysis is complicated by correlation among exposure levels, and the resulting collinearity makes the results difficult to interpret. METHODS: Patients with breast-related surgery at Yale-New Haven Hospital were interviewed using a standardized questionnaire, and breast adipose tissue samples were analysed for nine PCB congeners (74, 118, 138, 153, 156, 170, 180, 183, 187). The study recruited 490 women (304 cases and 186 controls) between 1994 and 1997. Logistic ridge regression was used to analyse the instability caused by collinearity. RESULTS: Although total PCB did not appear to be associated with breast cancer risk, significant differences in effect were observed among the nine congeners. Logistic ridge regression demonstrated a protective effect on breast cancer risk for a potentially anti-oestrogenic and dioxin-like congener, 156, while two phenobarbital, CYP1A and CYP2B inducers had an adverse effect, 180 and 183. This analysis also suggested that a protective effect for another phenobarbital congener, 153, was largely explained by instability caused by collinearity. CONCLUSIONS: These results indicate that studies of PCB congeners and health require an in-depth statistical analysis in order to better understand the complex issues related to their collinearity.

Adipose Tissue↗

Risk of female breast cancer associated with serum polychlorinated biphenyls and 1,1-dichloro-2,2'-bis(p-chlorophenyl)ethylene.

This case-control study was designed to investigate the relationship between polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2'-bis(p-chlorophenyl)ethylene (DDE) and breast cancer risk in Connecticut. Cases were incident breast cancer patients who were either residents of Tolland County or who had a breast-related surgery at the Yale-New Haven Hospital in New Haven County. Controls were randomly selected from Tolland County residents or from patients who had newly diagnosed benign breast diseases or normal tissue at Yale-New Haven Hospital. A total of 475 cases and 502 controls had their serum samples analyzed for PCBs and DDE in 1995-1997. The age- and lipid-adjusted geometric mean serum level of DDE was comparable between the cases (460.1 ppb) and controls (456.2 ppb). The geometric mean serum level of PCBs was also comparable between cases (733.1 ppb) and controls (747.6 ppb). After adjustment for confounding factors, odds ratios of 0.96 (95% confidence interval, 0.67-1.36) for DDE and 0.95 (95% confidence interval, 0.68-1.32) for PCBs were observed when the third tertile was compared with the lowest. Further stratification by parity, lactation, and menopausal and estrogen receptor status also showed no significant association with serum levels of DDE or PCBs. The results by PCB congener groups also showed no major increased risk associated with any of the congener groups. Our study does not support the hypothesis that DDE and PCBs, as encountered through environmental exposure, increase the risk of female breast cancer.

Adult↗

Trends in the incidence of non-melanoma skin cancer in Slovakia, 1978-1995.

Non-melanoma skin cancer (NMSC) incidence in Slovakia in the period 1978-1995 was analyzed. A total of 38,629 microscopically confirmed NMSC cases (19,600 in males and 19,029 in females) were registered by the National Cancer Registry: 31,714 (82.1%) were basal cell carcinomas (BCC), 6,396 (16.6%) squamous cell carcinomas (SCC) and only 519 (1.3%) other NMSC. Age standardized rates of NMSC increased in the given period by 59.1% in males and 58.5% in females. The greatest increase was observed for BCC, 70.4% and 65.0% in males and females respectively, the smaller for SCC, 13.5 and 18.8%. In the period 1993-1995 age-standardized incidence rates per 100,000 were 38.0 for BCC, 6.7 for SCC and 45.5 for all NMSC in males and 29.2, 3.8 and 33.6, respectively in females. The observed marked increase of incidence with age was particularly pronounced for SCC. In both sexes, head and neck was the most common localization of BCC and SCC (84.2 to 74.7%), followed by trunk for BCC (17.0% in males and 10.8% in females) and by upper limbs for SCC (with 11.6% in males and 12.5% in females). Very fast increase of BCC incidence over time, its slower increase with age as compared to SCC incidence and body-site distribution suggest that BCC etiology is much more similar to melanoma etiology than SCC one. Registration of NMSC in relation to changes in possible risk factors (i.e. sun exposure/protection, ozone layer decrease) is important to study the mechanism of disease occurrence and to support public health interventions.

Adolescent↗

Oxychlordane and trans-nonachlor in breast adipose tissue and risk of female breast cancer.

BACKGROUND: Organochlorine compounds, including organochlorine pesticides, have been suggested by some, but not all, studies to be associated with female breast-cancer risk. So far, studies relating organochlorine compounds and breast-cancer risk have mainly focused on polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) as risk factors for female breast cancer. This paper examines the hypothesis that environmental exposure to trans-nonachlor (TNC) and oxychlordane (OCD), a major metabolite of the insecticide chlordane, increases the METHODS: A total of 304 histologically confirmed, incident primary breast-cancer patients and 186 histologically confirmed incident benign breast-disease controls were included in the study between 1994 and 1997. Breast adipose tissue not needed for diagnostic purposes was collected and analysed for TNC, OCD and other organochlorine compounds. A standardised, structured questionnaire was used to obtain information on major known, or suspected, risk factors for breast cancer. RESULTS: The age and lipid-adjusted geometric mean adipose-tissue levels of OCD were similar between the cases [36.4 p.p.b., 95% confidence interval (CI) 34.7-38.2 p.p.b.] and controls (38.0 p.p.b., 95% Cl 35.7-40.6 p.p.b.). The age and lipid-adjusted geometric mean adipose-tissue levels of TNC between the cases (55.5 p.p.b., 95% CI 52.6-58.5 p.p.b.) and controls (58.1 p.p.b., 95% CI 54.2-62.3 p.p.b.) were also similar. There was no association between breast-cancer risk and mean adipose-tissue levels of OCD and TNC. The covariate-adjusted odds ratio (OR) was 0.7 (95% CI 0.4-1.3) for OCD and 1.1 (95% CI 0.6-1.9) for TNC, when the highest quartile was compared with the lowest. The risk also did not vary based on oestrogen or progesterone receptor status or menopausal status. DISCUSSION: We found no significantly increased risk of breast cancer associated with breast adipose-tissue levels of OCD or TNC; this is consistent with recent epidemiological studies, indicating that environmental exposure to organochlorine compounds does not have an overall significant impact on breast-cancer risk.

Adipose Tissue↗

A case-control study of toenail selenium and cancer of the breast, colon, and prostate.

To study the possible role of dietary and supplementary selenium intake in the etiology of cancer, we carried out a case-control study of breast, colon, and prostate cancer in Montreal between 1989 and 1993. In this study, we were able to interview a total of 1,048 incidence cases of colon (402), breast (414) and prostate (232) cancer subjects and 688 population-based controls matched for age and gender. Of these, a total of 501 cancer cases and 202 controls produced toenail samples for their selenium concentrations, which were determined by neutron activation analysis. We found no association between toenail selenium and breast cancer (odds ratio [OR], 0.72; 95% confidence interval [CI], 0.4-1.31) or prostate cancer (OR, 1.14; 95% CI, 0.46-2.83), though we did observe a statistically significant inverse association between toenail selenium level and the risk of colon cancer for both genders combined (OR, 0.42; 95% CI, 0.19-0.93; P = .009) and for female subjects (P = .050). We also found that nonsmoker case and control subjects had higher selenium in their toenail samples. This could be due either to the nature of tobacco, which reduces selenium absorption, or to smokers' consumption of certain foods containing less selenium. Further epidemiologic studies are required to clarify the role of selenium in the etiology of certain cancers.

Adolescent↗

Fast and flexible: the cephalopod repertoire.

The cephalopods differ remarkably from their molluscan cousins such as snails and bivalves. Fast moving, active predators, they have behavioural and physiological capabilities that stimulate and fascinate marine zoologists. Research on their methods of prey capture and handling, in particular, demonstrates the adaptability of the cephalopod format.

Animals↗

DDE and DDT in breast adipose tissue and risk of female breast cancer.

A case-control study was conducted in Connecticut from 1994 to 1997 to investigate the relation between dichlorodiphenyldichloroethane (DDE) and dichlorodiphenyltrichloroethane (DDT) exposure and breast cancer risk. Cases and controls were women aged 40-79 years, who had breast-related surgery at the Yale-New Haven Hospital and from whose surgical specimen the authors could obtain at least 0.4 g of breast adipose tissue for chemical analyses. A total of 304 incident breast cancer cases (including 62 in situ carcinomas) and 186 benign breast disease controls were recruited into the study. Tissue levels of DDE and DDT were measured using gas chromatography. Statistical significance for comparisons of mean levels of DDE and DDT was calculated using analysis of variance and rank sum tests. A logistic regression model was used to estimate the association and to control confounding. The age-adjusted geometric mean tissue level of DDE for cases (736.5 ppb) was similar to that for the controls (784.1 ppb). DDT levels were also similar for cases (51.8 ppb) and controls (55.6 ppb). The adjusted odds ratio is 0.9 (95% confidence interval: 0.5, 1.5) for DDE and 0.8 (95% confidence interval: 0.5, 1.5) for DDT when the highest quartile was compared with the lowest. These results do not support an association between adipose tissue levels of DDE and DDT and breast cancer risk.

Adipose Tissue↗

Cancer in patients on dialysis for end-stage renal disease: an international collaborative study.

BACKGROUND: Previous studies have suggested that the frequency of cancer is higher in patients with end-stage renal disease (ESRD) than in the general population, but have not established whether this increase is confined to certain cancers or to certain categories of ESRD patients. The aim of this study was to examine the risk of cancer in a large cohort of patients treated by dialysis but not transplantation. METHODS: We assembled a cohort of 831,804 patients who received dialysis during the period 1980-94 for ESRD in the USA, Europe, Australia, or New Zealand. We compared the observed frequency of cancer among these patients during 2,045,035 person-years of follow-up with the frequency of cancer in the respective background populations. FINDINGS: During average follow-up of 2.5 years, 25,044 (3%) of 831,804 patients developed cancer compared with an expected number of 21,185 (standardised incidence ratio 1.18 [95% CI 1.17-1.20]). We observed a higher risk of cancer in patients younger than 35 years (3.68 [3.39-3.99]), and the risk gradually decreased with increasing age. High risks were observed for cancer of the kidney (3.60 [3.45-3.76]), bladder (1.50 [1.42-1.57]), and thyroid and other endocrine organs (2.28 [2.03-2.54]). Excess cancers appeared in several organs for which viruses have been suspected as causative agents, whereas cancers of the lung, colorectum, prostate, breast, and stomach were not consistently increased. INTERPRETATION: The overall risk of cancer is increased in patients with ESRD, and the distribution of tumour types resembles the pattern seen after transplantation (although we have no data to make the comparison with skin cancer). The excess risk can largely be ascribed to effects of underlying renal or urinary-tract disease, or of loss of renal function, on the kidney and bladder, and to increased susceptibility to viral carcinogenesis. The relative risk, which is especially high in younger patients, gradually diminishes with age.

Adolescent↗