Respiratory response to endotoxin and dust predicts evidence of inflammatory response in volunteers in a swine barn.

BACKGROUND: It has been shown that exposure in intense exposure in swine barn facilities is associated with increased respiratory symptoms and reduction in pulmonary functions. This study investigated if systemic response could be predicted by FEV(1) response following swine barn exposure. METHODS: Naïve males were tested at baseline, low and high endotoxin and dust levels. Subjects were classified as "more responsive" (n = 9) or "less responsive" (n = 11) based on FEV(1) reduction following high endotoxin exposure. Health measures included pulmonary function testing, blood samples and nasal lavage. Environmental samples were collected from the barn. RESULTS: White blood cells and blood lymphocytes at low exposure were significantly greater in those who were "more responsive" compared to those who were "less responsive". There was a significant increase in blood lymphocytes, serum IL6, total nasal lavage cells and nasal IL8 at high exposure among "more responsive" subjects compared to "less responsive" subjects. CONCLUSIONS: Respiratory response to high-level endotoxin and dust exposure predicts evidence of inflammatory response throughout a range of endotoxin and dust exposures.

Endothelin-1-induced proliferation of human endothelial cells depends on activation of K+ channels and Ca+ influx.

AIMS: Endothelin-1 (ET-1) promotes endothelial cell growth. Endothelial cell proliferation involves the activation of Ca2+-activated K+ channels. In this study, we investigated whether Ca2+-activated K+ channels with big conductance (BK(Ca)) contribute to endothelial cell proliferation induced by ET-1. METHODS: The patch-clamp technique was used to analyse BK(Ca) activity in endothelial cells derived from human umbilical cord veins (HUVEC). Endothelial proliferation was examined using cell counts and measuring [3H]-thymidine incorporation. Changes of intracellular Ca2+ levels were examined using fura-2 fluorescence imaging. RESULTS: Characteristic BK(Ca) were identified in cultured HUVEC. Continuous perfusion of HUVEC with 10 nmol L(-1) ET-1 caused a significant increase of BK(Ca) open-state probability (n = 14; P < 0.05; cell-attached patches). The ET(B)-receptor antagonist (BQ-788, 1 micromol L(-1)) blocked this effect. Stimulation with Et-1 (10 nmol L(-1)) significantly increased cell growth by 69% (n = 12; P < 0.05). In contrast, the combination of ET-1 (10 nmol L(-1)) and the highly specific BK(Ca) blocker iberiotoxin (IBX; 100 nmol L(-1)) did not cause a significant increase in endothelial cell growth. Ca2+ dependency of ET-1-induced proliferation was tested using the intracellular Ca2+-chelator BAPTA (10 micromol L(-1)). BAPTA abolished ET-1 induced proliferation (n = 12; P < 0.01). In addition, ET-1-induced HUVEC growth was significantly reduced, if cells were kept in a Ca2+-reduced solution (0.3 mmol L(-1)), or by the application of 2 aminoethoxdiphenyl borate (100 micromol L(-1)) which blocks hyperpolarization-induced Ca2+ entry (n = 12; P < 0.05). CONCLUSION: Activation of BK(Ca) by ET-1 requires ET(B)-receptor activation and induces a capacitative Ca2+ influx which plays an important role in ET-1-mediated endothelial cell proliferation.

Prolonged vitamin C supplementation and recovery from eccentric exercise.

We have previously shown that vitamin C supplementation affects recovery from an unaccustomed bout of demanding exercise, with the most pronounced effect being that on plasma interleukin-6 concentration. However, because of the proposed role of interleukin-6 in the regulation of metabolism, it was unclear whether this represented a reduced response to muscle damage or some form of interaction with the metabolic demands of the activity. Therefore, the aim of the present study was to investigate the effect of the same form of supplementation on a bout of exercise that initiated similar muscle damage but had a low metabolic cost. Fourteen male subjects were allocated to either a placebo (P) or a vitamin C (VC) group. The VC group consumed 200 mg of ascorbic acid twice a day for 14 days prior to a bout of exercise and for the 3 days after exercise. The P group consumed identical capsules that contained 200 mg lactose. Subjects performed 30 min of downhill running at a gradient of -18% and recovery was monitored for up to 3 days after exercise. Plasma VC concentrations in the VC group increased following supplementation. Nevertheless, downhill running provoked a similar increase in circulating markers of muscle damage (creatine kinase activity and myoglobin concentration) and muscle soreness in P and VC groups. Similarly, although downhill running increased plasma interleukin-6, there was no effect from VC supplementation. These results suggest that vitamin C supplementation does not affect interleukin-6 concentrations following eccentric exercise that has a low metabolic component.

Plasma cytokine profiles in elderly humans.

It is known that as we age, immune dysregulation often occurs, leading to failing health, and increased susceptibility to a number of different diseases. In this study we have investigated plasma cytokine profiles in order to identify immune markers of ageing. Plasma samples were obtained from 138 participants of the Swedish longitudinal NONA study (aged 86, 90 and 94 years) and 18 healthy Swedish volunteers (aged between 32 and 59 years). Our results show significantly increased levels of the pro-inflammatory cytokine interleukin-6 (P<0.0001) and soluble intercellular adhesion molecule-1 (P<0.0001) in the elderly group. The anti-inflammatory cytokine interleukin-10 did not alter with age whereas active (naturally processed) transforming growth factor-beta levels were significantly (P<0.0001) increased in the elderly group. No difference was observed between males and females. These data suggest that there are measurable changes in cytokine profiles with ageing with increased levels of potentially harmful molecules, which may contribute to immune alterations and declining health in the elderly population.

Cardiac surgery increases the activity of matrix metalloproteinases and nitric oxide synthase in human hearts.

OBJECTIVES: Heart function is variably impaired after cardiopulmonary bypass. We hypothesized that, similar to other myocardial injury states, cardiopulmonary bypass leads to enhanced activity of nitric oxide synthase and matrix metalloproteinases. METHODS: We obtained right atrial biopsy specimens and plasma samples at the onset and termination of cardiopulmonary bypass in 10 patients. Biopsy specimens were analyzed for nitric oxide synthase activity by using a citrulline assay, whereas plasma and tissue were analyzed for matrix metalloproteinase-9 and matrix metalloproteinase-2 activity by using zymography. Tissue inhibitor of metalloproteinase-4 was analyzed by means of Western blotting. The cellular expression of inducible nitric oxide, endothelial nitric oxide synthase, matrix metalloproteinase-2, and matrix metalloproteinase-9 was determined in right atrial biopsy samples from 3 additional patients by using the appropriate conjugated antibodies. RESULTS: Nitric oxide synthase activity increased from the beginning to the end of bypass (4.46 +/- 1.07 vs 16.77 +/- 4.86 pmol citrulline/mg of protein per minute, respectively; P =.018). Pro-matrix metalloproteinase-9 activity increased in hearts (199 +/- 41 vs 660 +/- 177 density units/mg protein; P =.008) and plasma (14.1 +/- 4.6 vs 52.2 +/- 5.9 density units/mg protein; P =.008). Pro-matrix metalloproteinase-2 activity increased in the heart (201 +/- 23 vs 310 +/- 35 density units/mg protein, P <.05) but not in plasma. Tissue inhibitor of metalloproteinase-4 expression in the heart decreased (1574 +/- 280 vs 864 +/- 153 density units, P =.014). CONCLUSIONS: Cardiopulmonary bypass activates enzymes mediating acute inflammation and organ injury (ie, nitric oxide synthase, matrix metalloproteinase-9, and matrix metalloproteinase-2). Decreased tissue inhibitor of metalloproteinase-4 expression allows relatively unopposed increases in matrix metalloproteinase tissue activity. We postulate that these changes play a role in the pathogenesis of heart dysfunction after bypass surgery.

HIV-1-related pleural tuberculosis: elevated production of IFN-gamma, but failure of immunity to Mycobacterium tuberculosis.

BACKGROUND: Pleural tuberculosis can resolve spontaneously, suggesting that the inflammatory process may represent a protective immune response. However, pleural tuberculosis is strongly associated with HIV infection. It has been suggested that cell-mediated immune responses may be reduced, and direct bacterial invasion may have a role in pathogenesis, in HIV-positive cases. To test this hypothesis, we compared production of the pro-inflammatory cytokines, interferon (IFN)-gamma and tumour necrosis factor(TNF)-alpha, production of the immunosuppressive cytokine, interleukin (IL)-10, and mycobacterial culture positivity, in HIV-negative and HIV-positive patients with pleural tuberculosis. METHODS: Cytokine levels were measured in serum and pleural fluid, and in supernatants of blood and pleural fluid stimulated in vitro using mycobacterial antigens. Intracellular IFN-gamma and TNF-alpha production was measured after stimulation with phorbol myristate acetate and ionomycin in vitro. RESULTS: IFN-gamma was strikingly elevated in serum and pleural fluid in HIV-positive, compared to HIV-negative subjects (P < or = 0.02). TNF-alpha was elevated, but this was not statistically significant. IL-10 levels were higher in serum (P < 0.001), but similar in pleural fluid. IFN-gamma responses to soluble mycobacterial antigen in vitro were reduced in peripheral blood (P = 0.006), but not pleural fluid, of HIV-positive subjects. Intracellular cytokine staining suggested that CD8+ T cells were a major source of IFN-gamma in HIV-positive subjects. The proportion of subjects with a positive culture for Mycobacterium tuberculosis from pleural fluid was higher in the HIV-positive group. CONCLUSIONS: HIV-positive patients with pleural tuberculosis show elevated production of IFN-gamma, for which CD8+ T cells may be a major source. Mycobacterium tuberculosis can proliferate despite high levels of pro-inflammatory cytokines.

Influence of dietary supplementation with long-chain n-3 or n-6 polyunsaturated fatty acids on blood inflammatory cell populations and functions and on plasma soluble adhesion molecules in healthy adults.

Greatly increasing the amounts of flaxseed oil [rich in alpha-linolenic acid (ALNA)] or fish oil (FO); [rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] in the diet can decrease inflammatory cell functions and so might impair host defense. The objective of this study was to determine the effect of dietary supplementation with moderate levels of ALNA, gamma-linolenic acid (GLA), arachidonic acid (ARA), DHA, or FO on inflammatory cell numbers and functions and on circulating levels of soluble adhesion molecules. Healthy subjects aged 55 to 75 yr consumed nine capsules per day for 12 wk. The capsules contained placebo oil (an 80:20 mix of palm and sunflowerseed oils) or blends of placebo oil with oils rich in ALNA, GLA, ARA, or DHA or FO. Subjects in these groups consumed 2 g ALNA; approximately 700 mg GLA, ARA, or DHA; or 1 g EPA plus DHA (720 mg EPA + 280 mg DHA) daily from the capsules. Total fat intake from the capsules was 4 g per day. None of the treatments affected inflammatory cell numbers in the bloodstream; neutrophil and monocyte phagocytosis or respiratory burst in response to E. coli; production of tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 in response to bacterial lipopolysaccharide; or plasma concentrations of soluble intercellular adhesion molecule-1. In contrast, the ALNA and FO treatments decreased the plasma concentrations of soluble vascular cell adhesion molecule-1 (16 and 28% decrease, respectively) and soluble E-selectin (23 and 17% decrease, respectively). It is concluded that, in contrast to previous reports using higher amounts of these fatty acids, a moderate increase in consumption of long-chain n-6 or n-3 polyunsaturated fatty acids does not significantly affect inflammatory cell numbers or neutrophil and monocyte responses in humans and so would not be expected to cause immune impairment. Furthermore, we conclude that moderate levels of ALNA and FO, which could be incorporated into the diet, can decrease some markers of endothelial activation and that this mechanism of action may contribute to the reported health benefits of n-3 fatty acids.

Influence of age and dietary fish oil on plasma soluble adhesion molecule concentrations.

Soluble forms of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and E-selectin (termed sICAM-1, sVCAM-1 and sE-selectin respectively) are found in the plasma, and are elevated during inflammatory conditions in which there is increased expression of the cellular forms of the molecules on endothelial and other cells. sICAM-1, sVCAM-1 and sE-selectin concentrations were measured in the plasma of 140 healthy Caucasian subjects aged between 18 and 75 years (100 males/40 females). sICAM-1 concentrations varied between 59.9 and 299.7 ng/ml (median 150 ng/ml), sVCAM-1 concentrations varied between 222.8 and 1672.9 ng/ml (median 662 ng/ml) and sE-selectin concentrations varied between 12.4 and 90.3 ng/ml (median 45.5 ng/ml). There were significant positive linear correlations between age and the plasma concentrations of sICAM-1 (r=0.580; P<0.001) and sVCAM-1 (r=0.392; P<0.001), which were retained when the effects of gender, body mass index and fasting plasma triacylglycerol and total cholesterol concentrations were controlled for. The significant positive linear correlation between age and the plasma concentration of sE-selectin (r=0.234; P=0.027) was lost when other variables were controlled for. Male subjects <40 years of age had significantly lower plasma concentrations of both sICAM-1 and sVCAM-1 than males >55 years of age (both P<0.001), but the difference in plasma sE-selectin concentrations between the age groups did not reach significance (P=0.073). Subgroups of 16 males aged <40 years and 12 elderly subjects (>55 years of age) participated in a doubled-blind, placebo-controlled study of fish oil supplementation over 12 weeks. The level of eicosapentaenoic acid in plasma phospholipids did not change with placebo supplementation, but was significantly increased with fish oil supplementation in both young male and elderly subjects (median increase 200%). sICAM-1, sVCAM-1 and sE-selectin concentrations were unaffected by supplementation with placebo in either young male or elderly subjects. sICAM-1 concentrations were unaffected by fish oil supplementation. sE-selectin concentrations were significantly increased by fish oil supplementation in young males (P=0.043; median increase 38%), but fish oil tended to decrease plasma sE-selectin concentrations in the elderly subjects (P=0.075), with a median decrease of 11%. sVCAM-1 concentrations were unaffected by fish oil supplementation in young males. Fish oil supplementation significantly decreased plasma sVCAM-1 concentrations in the elderly subjects (P=0.043), with a median decrease of 20% (range 16-60%). These observations suggest that fish oil decreases endothelial activation in elderly subjects.

Positive human health effects of wearing a respirator in a swine barn.

STUDY OBJECTIVES: A study was conducted to evaluate the acute health effects of wearing an N-95 disposable respirator in a swine confinement facility. DESIGN: A crossover trial design was used in the study. SETTING: The study was carried out at the research facilities of the Centre for Agricultural Medicine, the Royal University Hospital, and the Prairie Swine Centre Inc, Saskatoon, Saskatchewan, Canada. PARTICIPANTS: Twenty-one nonsmoking healthy male subjects with no previous swine barn exposure participated in the study. INTERVENTIONS: The subjects participated in a laboratory session (baseline day), a 4-h exposure in a traditional swine room wearing the respirator (intervention day), and a 4-hour exposure in a traditional swine room without a respirator (nonintervention day). MEASUREMENTS: Lung function, methacholine challenge tests, blood counts, nasal lavage, and cytokines in serum and nasal lavage fluid. RESULTS: Mean (+/- SE) shift change in FEV(1), from preexposure to postexposure, was highest on nonintervention day (-8.1+/-1.01%) and was significantly different from intervention day (0.32+/-0.62%; p<0.0001) and baseline day (1.57+/-0.51%; p<0.0001). Similar patterns were observed in the mean values of the provocative concentration of a substance (methacholine) causing a 20% fall in FEV(1) (nonintervention day, 130.4+/-36.9 mg/mL; intervention day, 242.0+/-38.0 mg/mL; and baseline day, 328.0 mg/mL +/-34.1 mg/mL). Significant increases in serum neutrophil levels and nasal cell counts were observed on the nonintervention day in comparison to the baseline and intervention days. Significant increases also were found in the levels of cytokines interleukin (IL)-6 and IL-8 in nasal lavage fluid and in the levels of IL-6 in serum for the nonintervention day in comparison to the other 2 days. CONCLUSIONS: The results demonstrate that an N-95 disposable respirator can help to significantly reduce acute negative health effects in subjects not previously exposed to a swine barn environment.

Diurnal stability of refraction after implantation with intracorneal ring segments.

PURPOSE: To investigate diurnal changes in visual acuity and refraction in myopic eyes implanted with intracorneal ring segments (ICRS). SETTING: University of California San Diego Shiley Eye Center, La Jolla, California, and Emory University Vision Correction Center, Atlanta, Georgia, USA. METHODS: This prospective study involved 2 groups of patients who had ICRS (Intacs) implantation and a follow-up of at least 6 months. The first group included 102 eyes of 51 bilaterally treated patients; the second group, 32 eyes of 16 unilaterally treated patients. Examinations including visual acuity, manifest refraction, and videokeratography were done in the morning and evening at least 9 hours apart on a single day. Refractive changes were analyzed by power vectors; multivariate statistics were used to determine the significance of change in any component of the spectacle prescription. RESULTS: In the bilateral treatment group, 97 eyes (95%) were within 1 line of spectacle-corrected visual acuity from morning to evening. The mean change in manifest refraction was -0.14 +0.08 x 4 and in spherical equivalent, -0.10 diopters (D) (sigma = 0.3; range -0.750 to +0.875 D). Ninety-six eyes (94%) had a change in refraction within 0.50 D of spherical equivalent. There was no significant change in corneal power (P =.20). In the unilateral treatment group, there was no significant difference between treated and untreated eyes in changes in spectacle-corrected visual acuity, manifest refraction, or corneal power and toricity (P.05). CONCLUSION: No clinically significant diurnal variation in visual acuity or manifest refraction was observed after ICRS implantation or in untreated paired eyes. Moreover, the data suggest less diurnal change in visual acuity and refraction after ICRS implantation.

CYP17 promotor polymorphism and ovarian cancer risk.

The CYP17 gene encodes the cytochrome P450c17alpha enzyme, which functions at 2 different points in the steroid biosynthesis pathway, and is considered a candidate susceptibility gene for endocrine-related tumors. A T to C substitution polymorphism exists in the 5' promoter region of this gene, and creates an additional Sp1-type motif. Several studies have examined this polymorphism as a risk factor for breast cancer, but results have been conflicting. We examined 319 cases of ovarian cancer and 298 unaffected controls for the T-C polymorphism. There was no significant difference between cases and controls for the allele frequencies (p = 0.6), or for genotype distribution (p = 0.9). The odds ratio (95% confidence interval) for ovarian cancer was 1.13 (0.70-1.82) for the putative "cancer susceptibility" CC genotype and 1.07 (0.77-1.48) for any C allele (CC or CT genotype). Results were little different after adjustment for age. Stratification of the ovarian cancer cases according to form (benign, low malignant potential or invasive), histology, grade or stage failed to reveal any heterogeneity with respect to CYP17 genotype. Our data provide no evidence for an association between ovarian cancer risk and the genotype defined by the CYP17 5' promoter region T-C polymorphism.

beta-catenin mutation and expression analysis in ovarian cancer: exon 3 mutations and nuclear translocation in 16% of endometrioid tumours.

The molecular mechanisms involved in the generation of epithelial ovarian cancers are poorly understood, but evidence suggests that the different histological subtypes may arise from independent tumorigenic events. beta-Catenin is emerging as an important oncogene in the transformation of a number of epithelial cancers, and mutations have been reported in a small study of endometrioid ovarian adenocarcinomas. Mutations in the NH(2)-regulatory domain of beta-catenin stabilise the cytoplasmic levels of this protein, which promotes up-regulation of the beta-catenin-T-cell factor-lymphoid enhancer factor transcriptional complex. We report here beta-catenin (CTNNB1) exon 3 mutation analysis in 149 epithelial ovarian carcinomas. This revealed 10/63 (16%) endometrioid ovarian tumours with activating mutations of the beta-catenin gene. All mutations were missense changes within the GSK3beta consensus site, affecting serine residues at codons 33 and 37 and glycine at codon 34. Immuno-histochemical analysis identified cytoplasmic stabilisation and nuclear translocation in those endometrioid tumours with mutations. This phenotypic change was also identified in 3 other endometrioid tumours that did not have somatic mutations within exon 3 of CTNNB1. Stabilisation of the free, monomeric pool of beta-catenin and the probable resulting constitutive activation of its Tcf-associated transcriptional complex appears to be a specific oncogenic event in endometrioid ovarian adenocarcinoma.

Increased nitric oxide synthase activity after canine cardiopulmonary bypass is suppressed by s-nitrosoglutathione.

OBJECTIVES: Hemodynamic instability and generalized organ dysfunction are common after cardiopulmonary bypass in human beings. Previous studies have suggested that alterations of nitric oxide metabolism may be associated with this impaired function. Using a canine model we tested whether nitric oxide synthase activity is increased after cardiopulmonary bypass. We also tested whether administration of a nitric oxide donor can influence nitric oxide synthase activity after cardiopulmonary bypass. METHODS: After induction of anesthesia, dogs were randomized to receive cardiopulmonary bypass (n = 12) or to serve as controls (n = 12). They were further randomized to receive a continuous infusion of a nitric oxide donor, S-nitrosoglutathione, or an equivalent volume of placebo. Cardiopulmonary bypass was maintained for 90 minutes, and then 4 hours later dogs were put to death. Cardiac and coronary artery sections were frozen in liquid nitrogen immediately after death for later determination of nitric oxide synthase activity using a citrulline assay. RESULTS: After cardiopulmonary bypass, 4 of 6 placebo-treated but only 2 of 6 S-nitrosoglutathione treated animals required phenylephrine infusion (3.1 +/- 3.1 microgram/min and 0.2 +/- 0.4 microgram/min, respectively, P =.05) to maintain a predetermined blood pressure. Furthermore, after cardiopulmonary bypass, Ca2+-dependent nitric oxide synthase activity in the left ventricle, atrium, and coronary artery did not increase compared with activity in the control animals, but Ca2+-independent nitric oxide synthase activity did increase (P =.005): left ventricle (+28.0% +/- 9.0%), atrium (+45.0% +/- 12.0%) and coronary artery (+17.0% +/- 12.0%). CONCLUSIONS: We have found that (1) cardiopulmonary bypass results in increased activity of Ca2+-independent nitric oxide synthase, (2) S-nitrosoglutathione can prevent the increase of Ca2+-independent nitric oxide synthase after cardiopulmonary bypass, and (3) Ca2+-independent nitric oxide synthase may contribute to hemodynamic dysfunction after cardiopulmonary bypass.

The immune response to Mycobacterium tuberculosis in HIV-infected and uninfected adults in Uganda: application of a whole blood cytokine assay in an epidemiological study.

SETTING: Out-patient clinic, Entebbe, Uganda. BACKGROUND: It has been proposed that 'type 1' cytokines are essential in protective immunity to Mycobacterium tuberculosis and that suppression of 'type 1' or a switch to a 'type 2' profile is deleterious. We employed a simple assay to examine whether the dependence of the immunological responses to mycobacterial antigens on a range of explanatory factors could be determined in a population where tuberculosis is endemic. OBJECTIVE: To determine the relationship between the tuberculin skin test response and cytokine profile, and the effect of human immunodeficiency virus (HIV) infection. DESIGN: A cross-sectional study of 97 Ugandan adults (22 HIV-positive, 75 HIV-negative). Whole blood was stimulated in vitro using mycobacterial antigens (purified protein derivative [PPD] and culture filtrate proteins [CFP]). 'Type 1' cytokines (gamma interferon [IFN-gamma] and interleukin-2 [IL-2]), 'type 2' cytokines (IL-5 and IL-10) and tumour necrosis factor alpha (TNF-alpha) were measured in culture supernatants. RESULTS: Among HIV-negative subjects, a positive tuberculin skin test was associated with type 1 or mixed (type 1 + type 2) cytokine production, but a positive IFN-gamma response also occurred in a proportion of tuberculin skin test negative subjects (36% for PPD, 17% for CFP). In association with HIV infection, IFN-gamma responses to mycobacterial antigens were profoundly impaired (odds ratio [OR] 0.10 for PPD, 0.06 for CFP, P< or =0.001), but production of IL-2, IL-5 and TNF-alpha was relatively sustained, and IL-10 increased or sustained (OR 3.97 for PPD, P = 0.01, 1.14 for CFP, P = 0.99). CONCLUSION: The type 1/type 2 cytokine balance was not defined by the tuberculin skin test response, and may have a closer relation to protective immunity. IFN-gamma production was strikingly impaired in association with HIV infection, while production of type 2 cytokines was sustained or increased. Use of a simple assay allowed a large sample of subjects to be examined, producing epidemiologically meaningful results.

Frequent loss of heterozygosity and three critical regions on the short arm of chromosome 8 in ovarian adenocarcinomas.

Many chromosomal regions undergo loss of heterozygosity (LOH) in ovarian adenocarcinomas but few of the target regions have been finely mapped. One of the chromosome arms likely to harbour one or more tumour suppressor genes inactivated in ovarian cancer is the short arm of chromosome 8 which is frequently deleted in many other solid tumours. We have examined a large panel of microsatellite markers on 8p for LOH in 53 ovarian adenocarcinomas. LOH was observed in 27 tumours (51%), with a significant trend towards a higher frequency of LOH in more advanced tumours. Detailed examination of nine tumours with partial deletions defined three regions of overlap, two in 8p23 and one in 8p22, which suggests that there might be as many as three tumour or metastasis suppressor genes on 8p which are inactivated during ovarian tumorigenesis. LOH on 8p was significantly associated with 9p LOH which suggests that inactivation of target genes on these chromosomes may be cooperative events.

No evidence for microsatellite instability from allelotype analysis of benign and low malignant potential ovarian neoplasms.

UNLABELLED: The genetic events that lead to the development of benign and low malignant potential (LMP) tumors from normal ovarian surface epithelium are not well understood. In contrast to invasive ovarian neoplasms, loss of heterozygosity (LOH) is not common in these tumors except on the X chromosome, but one report has suggested that an alternative genetic mechanism, microsatellite instability (MSI), might be an important pathogenic mechanism for LMP ovarian tumors. OBJECTIVE: To determine the frequency of MSI in LMP tumors and to detect novel regions of LOH in benign and LMP ovarian tumors. METHODS: Sixty-nine microsatellite markers were analyzed in 23 benign and 31 LMP ovarian tumors. RESULTS: No evidence of MSI was found in any of the tumors studied, nor were any novel regions of LOH identified. CONCLUSIONS: This suggests that new approaches may be necessary to understand the genetic basis of benign and LMP ovarian neoplasms since neither LOH nor MSI appears to play a major role.

Predictors of longitudinal changes in pulmonary function among swine confinement workers.

OBJECTIVE: To determine predictors of longitudinal changes in pulmonary function in swine confinement workers. DESIGN: Longitudinal study conducted from November 1989 to June 1991 and January 1994 to May 1995. SETTING: Swine confinement workers in Saskatchewan. PARTICIPANTS: Forty-two swine confinement workers who were studied in 1989/90 and studied again in 1994/95. RESULTS: Of 98 male swine confinement workers (mean age SD 36.3 11.1 years) studied at baseline, 42 were studied again five years following. Complete information on baseline across-shift pulmonary function (preshift forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC], and every 2 h FEV1 and FVC during the shift), and five-year follow-up pulmonary function (with FEV1 and FVC) were available on all 42 subjects. Mean across-shift changes (preshift measurement to last measurement of the day) at baseline were -159. 8 61.7 mL in FEV1 and -35.3 65.6 mL in FVC. Mean annual rate change between baseline and follow-up for FEV1 was -53.9 61.7 mL/year and for FVC -48.9 71.6 mL/year. After adjusting for age, height, smoking and hours spent in the barn, the baseline across-shift change in FEV1 and FVC was a significant predictor of annual rate change in FEV1 (P=0.01) and FVC (P=0.02), respectively. To determine the effects of indoor air quality on longitudinal lung function decline, indoor air environmental measurements were analysed. Complete information on respiratory health and indoor air quality was available on 34 of the 42 subjects. Assessment of indoor environment of swine barns included a summer and winter measurement for airborne dust, gases and endotoxin levels. After adjusting for age, height, smoking, ammonia and hours spent in the barn, the endotoxin level (Eu/mg)was a significant predictor of annual rate change for FEV1 but not FVC. CONCLUSIONS: These results suggest that shift change is an important predictor of longitudinal changes in lung function in swine confinement workers and that endotoxin exposures may mediate annual decline in FEV1 in these workers.

The effects of U-74389G, a 21-aminosteroid, on pulmonary vascular resistance after a scald.

We tested U-74389G (C37H50N6O2-CH4O4), a 21-aminosteroid, to determine whether it ameliorates the pulmonary vascular effects of a surface scald. We studied 24-anesthetized rabbits mechanically ventilated with 100% and then 13% O2. Twelve rabbits received a scald (75 degrees C water applied to the shaved ventral surface for 90 seconds), and 12 served as control (20 degrees C water). Six control and six scalded animals additionally received U-74389G (5 mg/ kg intravenously). We measured hemodynamics and blood gases prescald, 30 minutes postscald, and 30 minutes after U-74389G or placebo administration. The strength of hypoxic pulmonary vasoconstriction (HPV) was assessed as the difference between pulmonary vascular resistance measured during 13% O2 ventilation and during 100% O2 ventilation. Hemodynamics and gas exchange were similar between groups. The strength of HPV was significantly diminished postscald, but U-74389G treatment restored HPV to baseline values. We conclude that a scald reduces the strength of HPV, and the response to U-74389G suggests this may be mediated by free radicals.

Positive human health effects of dust suppression with canola oil in swine barns.

A crossover trial was conducted to evaluate the acute human health effects of a dust control technology in a swine confinement facility. Twenty lifetime nonsmoking male subjects, with no evidence of allergy or asthma and no previous swine barn exposure, participated in the study, which included a laboratory session (baseline), 5-h exposure in a swine room sprinkled with canola oil (treatment) and 5-h exposure in a traditional swine room (control). Mean values of inhalable dust concentrations and endotoxin levels in the control room were significantly greater than those observed in the treatment room. Mean shift changes in FEV1 from preexposure to end of exposure were 1.1% (standard error, 0.63%) on baseline day, -1.9% (0.63%) on treatment day, and -9.9% (1.12%) on control day; the differences in the shift changes were statistically significant. Mean value of methacholine concentration that reduced the FEV1 by 20% (PC20) in bronchoprovocation tests on baseline day was significantly different from that on treatment day (p = 0.04) and that on control day (p < 0.001). Significant increases were also observed in white blood cell counts and nasal lavage cell counts on the control day in comparison with the other two days. Blood neutrophil counts after control room exposure were twice those observed on baseline and after exposure to the treatment room. Significant differences were also observed in IL-1 beta, IL-6, and IL-8 nasal lavage cytokines and in IL-6 serum cytokine. These results suggest that the canola oil dust control method is effective in improving indoor air quality in swine barns and reducing acute health effects in naive healthy subjects.