[Risk factors for incident cervical intraepithelial neoplasia (CIN) among HIV-infected women: a prospective study]. / Facteurs de risque d'acquisition de lésions du col utérin dans une population de femmes infectées par le VIH: étude prospective.

OBJECTIVES: To study risk factors for incident cervical intraepithelial neoplasia (CIN) among HIV-infected women. PATIENTS AND METHODS: Prospective study of a population of 97 HIV-infected women with normal Pap smear at inclusion. RESULTS: Fourteen CIN (diagnosed by colposcopy and confirmed with biopsy) were observed within a median follow-up of 38 months (13 CIN 1, one CIN 2). The incidence of cervical lesions was estimated to be 2%, 7% and 10% respectively at one year, two and three years after inclusion, The time to occurrence was very variable (ranging from 7 months to 6 years) among our patients. No known risk factors, in particular neither the CD4 cell count nor antiretroviral treatment, were identified to be associated with occurrence of CIN in our study population. CONCLUSION: Regardless of their immune status and HIV treatments, extensive and prolonged gynaecological follow up of HIV-infected women remains necessary.

Short-term exposures to dihaloacetic acids produce dysmorphogenesis in mouse conceptuses in vitro.

The haloacetic acids (HAAs) are a family of xenobiotics found in tap water as a result of drinking water disinfection. Administration of HAAs to rats produces a variety of adverse effects, including developmental toxicity. The dysmorphogenic potencies of all nine bromo/chloro-acetic acids have been determined in rodent whole embryo culture using standard 26-h exposure. Since the half-lives of the HAAs in vivo are typically <8 h, the developmental effects of short-term exposures to dihaloacetates were evaluated. Gestation day 8 (3-6 somite pairs) CD-1 mouse conceptuses were exposed to 11,000 microM dichloroacetic acid (DCA), 300 microM dibromoacetic acid (DBA) or 300 microM bromochloroacetic acid (BCA) for culture periods of 1, 3, 6 or 26 h. Following 1, 3 or 6 h of exposure to HAAs, conceptuses were transferred to control medium to complete a 26-h culture period. The amounts of HAAs present in embryos after 1, 3 and 6h of exposure were determined. Increased incidences of dysmorphic embryos were produced by 6 or 26-h exposures to DCA; a 26-h exposure to DBA; or 3, 6 or 26-h exposures to BCA. The dysmorphology produced was dependent upon the length of exposure and chemical. The embryonic concentration of each HAA (104.5, 2.5 and 2.6 pmol/microg protein for DCA, DBA and BCA, respectively) was reached by 1h of exposure and did not change at the subsequent time points examined. The current studies demonstrate that BCA is more potent than DBA or DCA at disrupting embryogenesis since shorter exposures alter morphogenesis. Since the embryonic HAA concentrations were the same at the three time points measured, the time-dependence in dysmorphogenesis does not appear to be a simple function of increasing embryonic concentration of these chemicals. These studies demonstrate that for these dihaloacetic acids relatively high concentrations and long exposures are needed to alter rodent development in vitro.

Cyclo-oxygenase-2 expression in Barrett's oesophageal carcinogenesis: an immunohistochemical study.

BACKGROUND: The incidence of Barrett's oesophageal adenocarcinoma is increasing more rapidly than any other malignancy in industrialized countries. Cyclo-oxygenase-2 appears to play an important role in gastrointestinal carcinogenesis. Previous studies on cyclo-oxygenase-2 expression in Barrett's oesophageal carcinogenesis have utilized tissue samples obtained from different patients. We sought a definitive comparison of cyclo-oxygenase-2 expression in the sequence of Barrett's metaplasia-dysplasia-adenocarcinoma within the same patients. METHODS: Paraffin-embedded oesophago-gastrectomy specimens from 20 patients, containing successive stages of Barrett's metaplasia, high-grade dysplasia and adenocarcinoma, were analysed for cyclo-oxygenase-2 expression by immunohistochemistry. RESULTS: Cyclo-oxygenase-2 was constitutively expressed in the basal layers of cells in the adjacent normal squamous oesophageal epithelium, but a higher cyclo-oxygenase-2 expression was observed in Barrett's metaplasia. A further increase in cyclo-oxygenase-2 expression was detected in high-grade dysplasia, but cyclo-oxygenase-2 was decreased in adenocarcinoma tissue, regardless of its stage or level of differentiation. CONCLUSIONS: Cyclo-oxygenase-2 expression is progressively increased when squamous oesophageal epithelium develops into Barrett's metaplastic epithelium and then into high-grade dysplasia, but appears to decrease when adenocarcinoma develops. These findings may be significant for an effective chemo-prevention strategy with selective cyclo-oxygenase-2 inhibitors.

Studies on the antilithic effect of Rotula aquatica lour in male Wistar rats.

The decoction of Rotula aquatica lour was screened for antilithic activity in male Wistar rats and the results were summarized based on the ionic changes in both urine and serum. Nephrolithiasis was induced in rats by feeding them 3% glycolic acid mixed feed for 45 days, which resulted in high urinary calcium, oxalate and high serum potassium. Simultaneous treatment with the decoction reduced calcium and oxalate ion concentration in urine, confirming the stone inhibitory effect. Histopathological studies of kidney tissue samples further substantiated the findings. The decoction was found to be nontoxic over the 45-day treatment period.

Dibromoacetic acid, a prevalent by-product of drinking water disinfection, compromises the synthesis of specific seminiferous tubule proteins following both in vivo and in vitro exposures.

Dibromoacetic acid (DBA) is a by-product of drinking water disinfection that alters spermatogenesis in adult male rats. To identify a mechanism by which DBA alters spermatogenesis, seminiferous tubules representing specific groups of spermatogenic stages were exposed either in vivo or in vitro, and structural and functional consequences were evaluated. Seminiferous tubules representing stages I-V, VI-VIII, and IX-XIV were isolated from testes of adult rats and cultured overnight in conditions of reduced oxygen and temperature. For in vivo exposures, seminiferous tubules were recovered from animals that had received 250 mg/kg DBA via gavage for 5 days. For in vitro exposures, 180 and 600 microM concentrations were tested; these concentrations bracket the concentration of DBA observed within the testis following in vivo exposure. Protein synthesis was evaluated by 35S-methionine labeling overnight and quantitative analysis of radiolabeled proteins in mini, 2-dimensional (2D) sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. Radio-inert cultures were processed for light and electron microscopy. Morphologicaf evaluation indicated that all spermatogenic stages of the seminiferous tubules from control animals were well maintained during the isolation and culture period. Although no treatment-related lesions were observed following in vivo exposure, histological alterations were observed at the lowest in vitro exposure. There was a significant diminution (P < .05) in the synthesis of 4 cytosolic proteins following both in vivo and in vitro exposures. Diminution in these proteins was restricted to stages I-V and IX-XIV of spermatogenesis, suggesting that proteins involved in the early stages of spermiogenesis are uniquely sensitive to DBA exposure. Because histology and protein synthesis were affected by relevant in vitro exposures, this indicates that DBA is capable of altering spermatogenesis directly.

Toward a biologically based dose-response model for developmental toxicity of 5-fluorouracil in the rat: acquisition of experimental data.

Biologically based dose-response (BBDR) models represent an emerging approach to improving the current practice of human health-risk assessment. The concept of BBDR modeling is to incorporate mechanistic information about a chemical that is relevant to the expression of its toxicity into descriptive mathematical terms, thereby providing a quantitative model that will enhance the ability for low-dose and cross-species extrapolation. Construction of a BBDR model for developmental toxicity is particularly complicated by the multitude of possible mechanisms. Thus, a few model assumptions were made. The current study illustrates the processes involved in selecting the relevant information for BBDR modeling, using an established developmental toxicant, 5-fluorouracil (5-FU), as a prototypic example. The primary BBDR model for 5-FU is based on inhibition of thymidylate synthetase (TS) and resultant changes in nucleotide pools, DNA synthesis, cell-cycle progression, and somatic growth. A single subcutaneous injection of 5-FU at doses ranging from 1 to 40 mg/kg was given to pregnant Sprague-Dawley rats at gestational day 14; controls received saline. 5-FU was absorbed rapidly into the maternal circulation, and AUC estimates were linear with administered doses. We found metabolites of 5-FU directly incorporated into embryonic nucleic acids, although the levels of incorporation were low and lacked correlation with administered doses. On the other hand, 5-FU produced dose-dependent inhibition of thymidylate synthetase in the whole embryo, and recovery from enzyme inhibition was also related to the administered dose. As a consequence of TS inhibition, embryonic dTTP and dGTP were markedly reduced, while dCTP was profoundly elevated, perhaps due to feedback regulation of intracellular nucleotide pools. The total contents of embryonic macromolecules (DNA and protein) were also reduced, most notably at the high doses. Correspondingly, dose-related reductions of fetal weight were seen as early as GD 15, and these deficits persisted for the remainder of gestation. These detailed dose-response parameters involved in the expression of 5-FU developmental toxicity were incorporated into mathematical terms for BBDR modeling. Such quantitative models should be instrumental to the improvement of high-to-low dose and cross-species extrapolation in health-risk assessment.

Toward a biologically based dose-response model for developmental toxicity of 5-fluorouracil in the rat: a mathematical construct.

Biologically based dose-response (BBDR) models comprise one way to incorporate mechanistic information into a dose-response assessment to be used for risk assessments. The chemotherapeutic drug 5-fluorouracil (5-FU) has been used as a prototypic compound for the construction of a BBDR model for developmental toxicity. Previous work has provided data and a general mechanistic framework for the developmental toxicity of 5-FU when it was administered to pregnant rats subcutaneously on gestation day 14. In this paper, a mathematical model relating maternally administered treatment with 5-FU to embryonal thymidylate synthetase inhibition and thymidylate synthetase inhibition to various measures of deoxyribonucleotide triphosphate (dNTP) pool perturbation is developed, and parameters are estimated using the data collected. The strategy used was to develop semi-empirical submodels for each of the intervening steps, and to estimate model parameters from previously described data. The models developed predict that there is no practical threshold for dNTP pool perturbation; that is, even minimal doses of 5-FU should result in some perturbation of dNTP pools. In particular, the relationship between dNTP pool perturbation and fetal weight deficit suggests that if there is a biological threshold for the effect of 5-FU on fetal weight, the responsible repair or compensation mechanism must be downstream of dNTP pool perturbation, and saturable at 5-FU doses lower than 10 mg/kg (the lowest dose examined for developmental effects in these studies).

Influence of the drinking water disinfection by-product dibromoacetic acid on rat estrous cyclicity and ovarian follicular steroid release in vitro.

The drinking water disinfection by-product, dibromoacetic acid (DBA) has been reported to affect gonadal functions in the male rat. However, there is little information regarding the influence of DBA on female reproductive activity. Consequently, the present study investigated the effects of DBA on estrous cyclicity and the impact in vitro of DBA on ovarian follicular steroid secretion. Regularly cycling animals were dosed with DBA (0 to 270 mg/kg/day) for 14 days and estrous cyclicity was monitored during treatment and for an additional 2-week posttreatment interval. A dose-related alteration in cyclicity was observed at 90 and 270 mg/kg/day, which persisted through the posttreatment monitoring in the high dose group. An in vitro exposure of preovulatory follicles to DBA was then used to assess the influence of DBA on steroid release. To select a concentration for use, a single oral exposure to 270 mg/kg was administered, and the mean blood levels were determined over a 5-h interval. For this in vitro work, pairs of preovulatory follicles from PMSG-primed immature rats were exposed to 0 or 50 microg/mL DBA over a 24-h period and evaluated for estradiol and progesterone release under baseline and hCG-stimulated conditions. The influence of tumor necrosis factor (TNFalpha) exposures under these conditions was also determined. In the nonstimulated condition, DBA was found to increase the release of estradiol, but had no detectable effect in response to hCG. Progesterone, however, showed marked suppression under hCG stimulation following exposure to DBA, while nonstimulated secretion was unaffected. TNFalpha by itself also suppressed stimulated progesterone release, but had no additional effect in combination with DBA. The data suggest that one factor in the disruption in estrous cyclicity could be an alteration in steroid production, which was characterized by separate effects on both estradiol and progesterone secretion.

Two-chain factor VIIa generated in the pericardium during surgery with cardiopulmonary bypass : relationship to increased thrombin generation and heparin concentration.

Several recent studies have proposed that coagulation is triggered during cardiopulmonary bypass surgery by extrinsic pathway activation involving factor VIIa generation, but the methodology was indirect. Therefore, 12 patients were studied during routine cardiac and cardiopulmonary bypass surgery. Samples were taken before, during, and after bypass from the perfusate, from the aorta (retrograde cardiac drainage), pericardium, and collected suction fluid originating from the whole operative field. These samples were analyzed by enzyme-linked immunosorbent assay for 2-chain factor VIIa, by prothrombin F1+2 assay, by thrombin-antithrombin (TAT) assay, and for heparin concentration. Factor VIIa, F1+2, and TAT levels in samples from the pericardium were greatly elevated (mean, 0.92 to 1.01, 227 to 334, and 399 to 526 microg/L, respectively; preoperative mean, 0.33, 32.3, and 1.90 microg/L, respectively; P<0. 05 for all), whereas levels in suction fluid were less consistently high. Factor VIIa and both F1+2 and thrombin-antithrombin levels in samples from the aorta, pericardium, and suction fluid were significantly correlated (r=0.57, P<0.001, n=111; and r=0.51, P<0. 001, n=105, respectively), and all were inversely correlated with heparin levels (r>-0.35, P<0.001, n>92). There was no evidence of factor VIIa generation in the circuit during bypass surgery, and both F1+2 and thrombin-antithrombin levels rose only approximately 2-fold, probably because heparin levels were higher than they were in the pericardium (P<0.05). We concluded that appreciable activation of factor VII occurs on the pericardium and that this is associated with increased thrombin generation. Ineffective local heparinization may be partly responsible. These results suggest that pericardium-induced activation of factor VII should be the target of anticoagulant strategies during cardiopulmonary bypass surgery.

Sample preparation and high-performance liquid chromatographic analysis of deoxyribonucleoside triphosphates in individual rat embryos.

A rapid, robust, and sensitive method has been developed to measure concentrations of deoxyribonucleoside triphosphates in individual, day 14 rat embryos by modifying and optimizing existing methods for cellular extracts. Significant changes include: (i) oxidative degradation of ribonucleoside triphosphates using methylamine at lower pH (decreased from 6.5 to 4.0) to improve poor HPLC peak shape of early eluting nucleotides; (ii) glass fiber disc solid-phase extraction of the reaction mixture, which dramatically reduces impurities that interfere with nucleotide measurement, eliminates the necessity of column regeneration, and allows mobile phase recycling; and (iii) lower ionic strength (reduced from 0.4 to 0.26 or 0.12 M ammonium phosphate) and higher pH (increased from 3.25 to 5.55 or 6.98, respectively) mobile phase, conditions which are less destructive to the column's bonded phase and silica support, thereby contributing to longer column life. Enhancements include: (i) filtration of the sample prior to HPLC injection and addition of an in-line filter, guard column, and saturating precolumn of silica in the mobile phase flow, which aids substantially in extending column life and improves chromatographic stability, and (ii) inclusion of an internal standard to correct for mechanical losses. Limits of determination at a signal to noise ratio of 6:1 range from 5.5 to 12 pmol on-column or 0.41 to 0.87 pmol/mg of embryonic tissue depending on the specific nucleotide. Recoveries are quantitative for all nucleotides, and interassay variabilities are between 5 and 7% when quantified by peak height. The method has also been applied successfully to analysis of murine erythroleukemic cell cultures and this, when coupled with the embryo results, suggests its general utility.

Nucleoside-mediated mitigation of 5-fluorouracil-induced toxicity in synchronized murine erythroleukemic cells.

5-Fluorouracil (5-FU) is a chemotherapeutic agent known to retard embryonic growth and induce cleft palate and limb deformities. The predominant mechanism underlying its toxic action is thought to be inhibition of thymidylate synthetase (TS), and hence thymidine triphosphate (dTTP) synthesis, resulting in alteration of the balance of deoxynucleotide (dNTP) pools and disruption of DNA synthesis. Indeed, previously we demonstrated retarded cell-cycle progression concurrent with a 60% decrease in TS activity in rat whole embryos following maternal exposure to 40 mg/kg 5-FU on Gestational Day 14 and in the murine erythroleukemic cell (MELC) suspension culture following exposure to 5-25 microM 5-FU for 2 hr. In the study described herein, we used high-performance liquid chromatography (HPLC) to demonstrate in both of these model systems that 5-FU exposure results in similar patterns of dNTP perturbations: a prolonged decrease in dTTP and dGTP levels and an increase in dCTP and dATP. In addition, we used centrifugal elutriation to synchronize MELC in the phases of the cell cycle (G0/G1 and early S) most sensitive to 5-FU to investigate the ability of nucleoside supplementation to mitigate 5-FU-induced toxicity. Our data indicate that following a 2-hr exposure to 5-25 microM 5-FU, supplementation with 1-10 microM thymidine (TdR) for 24 hr partially reverses 5-FU-induced toxicity as evidenced by increased cellular proliferation and cell-cycle progression and amelioration of 5-FU-induced perturbations of protein synthesis and cellular membrane permeability compared to unsupplemented 5-FU-exposed cells. However, TdR concentrations >/=100 microM inhibited growth or were cytotoxic. In comparison, supplementation with 10 microM-10 mM of deoxycytidine (CdR) was not toxic, but effected a dose-dependent recovery from 5-FU-induced toxicity. At 1-100 microM, neither deoxyadenosine nor deoxyguanosine supplementation reduced 5-FU-induced toxicity; at higher concentrations, both purine nucleotides inhibited cell growth. Although these results support the hypothesis that 5-FU disrupts the MELC cell cycle by depleting dTTP (a perturbation that is reversible by TdR supplementation), they also indicate that CdR supplementation offers an additional recovery pathway.

Critical periods of sensitivity to the developmental toxicity of inhaled methanol in the CD-1 mouse.

Exposure of pregnant CD-1 mice to methanol (MeOH) by inhalation on gestation days (gd) 6-15 results in dose-related increases in fetal cleft palate, exencephaly, and skeletal defects. Here, critical periods for the developmental toxicity of MeOH were assessed in pregnant CD-1 mice exposed to 10,000 ppm MeOH or filtered air for 7 hr/day on 2 consecutive days during gd 6-13, or to single day (7 hr) exposures to 10,000 ppm MeOH during gd 5-9. Mice received water but not food during exposure. Maternal blood MeOH was determined at times during, at the end of, and subsequent to a single 7 hr exposure on gd 7. On gd 17, remaining mice were weighed, killed, and gravid uteri removed. Live, dead, and resorbed fetuses were counted, and live fetuses were examined, weighed, and preserved in 70% ethanol. All fetuses were examined externally and for cleft palate, eviscerated, and stained with Alizarin red for skeletal examination. Pregnant mice lost an average of 0.3-2.9 g during 7 hr exposure to either filtered air or MeOH, but a MeOH treatment effect was evident only with 2-day exposure on gd 7-8. Peak maternal blood MeOH concentration (at the end of exposure) was approximately 4 mg/ml, and MeOH was cleared from maternal blood within 24 hr. Some fully resorbed litters were observed with 2-day MeOH exposures on gd 6-7 or 7-8, or 1-day exposure on gd 7. With 1-day MeOH exposure on gd 7, the number live was lower than with exposure on any other day. As previously reported, cleft palate, exencephaly, and skeletal defects were the fetal anomalies observed in this mouse strain. Cleft palate occurred with 2-day exposures on gd 6-7 through gd 11-12 (peak on gd 7-8), and with 1-day exposure on gd 5 through gd 9 (peak on gd 7). Exencephaly occurred with 2-day exposures on gd 6-7 through gd 8-9 (peak gd 6-7) or 1-day exposure on gd 5 through gd 8 (peak on gd 7). Skeletal elements malformed included the exoccipital (peak gd 6-7, gd 5), atlas (peak gd 6-7, gd 5,6), axis (peak gd 6-7, gd 7), cervical vertebra 7 with a rib (peak gd 6-7, gd 7), and lumbar vertebra 1 with a rib (peak gd 7-8, gd 7). An increased incidence of fetuses with 25 presacral vertebrae (normal = 26) was observed with methanol exposure on gd 5, whereas an increased incidence of fetuses with 27 presacral vertebrae was observed with MeOH exposure on gd 7. These results indicate that gastrulation and early organogenesis represent a period of increased embryonal sensitivity to methanol.

Cyclin D1 amplification and expression in human breast carcinoma: correlation with histological prognostic markers and oestrogen receptor expression.

Aims-To study the amplification of the Cyclin D1 gene (CCND1) in human breast carcinoma; to relate this to Cyclin D1 protein expression; to relate these parameters to recognised pathological prognostic factors, including oestrogen receptor (ER) status.Methods-DNA extracted from frozen sections of breast tumours (n = 36) was used for Southern blotting. Probes for CCND1, c-myc and the immunoglobulin heavy chain locus (IgH) were hybridised to tumour DNA. Immunocytochemical expression of Cyclin D1 protein and ER was studied in paraffin wax sections from the same tumours.Results-Amplification of CCND1 was observed in 11% (four of 36) of tumours studied. Over expression of Cyclin D1 protein was observed in 73% (30/41) of tumours. There was no correlation between recognised histological prognostic markers and either gene amplification or expression. However, a weak association was seen between Cyclin D1 expression and ER status.Conclusions-A disparity exists between locus amplification and over expression of Cyclin D1, suggesting the existence of another mechanism for raised protein expression. No significant correlation was detected between either Cyclin D1 amplification or over expression and established prognostic markers.

Assessment of offspring development and behavior following gestational exposure to inhaled methanol in the rat.

The prospect of widespread human exposure associated with its use as an alternative fuel has sparked concern about the toxic potential of inhaled methanol (MeOH). Previous studies have revealed congenital malformations in rats following inhaled MeOH (Nelson et al. (1985). Fundam. Appl. Toxicol. 5, 727-736) but these studies did not include postnatal behavioral assessment. In the present study, pregnant Long-Evans rats were placed in exposure chambers containing 15,000 ppm MeOH or air for 7 hr/day on Gestational Days (GD) 7-19. The total alveolar dose of methanol was estimated at about 6.1 g/kg/day, for a total dose of about 42.7 g/kg for the entire study. Maternal body weights were recorded daily and blood methanol concentrations were determined at the end of exposure on GD 7, 10, 14, and 18. Following birth (Postnatal Day 0 [PND 0]), a number of tests were performed at various points in development, including: offspring mortality and body wt (PND 1,3), motor activity (PND 13-21, 30, 60), olfactory learning (PND 18), behavioral thermoregulation (PND 20-21), T-maze learning (PND 23-24), acoustic startle response (PND 24, 60), reflex modification audiometry (PND 60), pubertal landmarks (PND 31-56), passive avoidance (PND 72), and visual-evoked potentials (PND 160). Maternal blood MeOH levels, measured from samples taken within 15 min after removal from the exposure chamber, declined from about 3.8 mg/ml on the first day of exposure to 3.1 mg/ml on the 12th day of exposure. MeOH transiently reduced maternal body wt (4-7%) on GD 8-10, and offspring BW (5%) on PND 1. No other test revealed significant effects of MeOH. Prenatal exposure to high levels of inhaled MeOH appears to have little effect on this broad battery of tests beyond PND 1 in the rat.

Nuclear and cytoplasmic bcl-2 expression in endometrial hyperplasia and adenocarcinoma.

The bcl-2 proto-oncogene, which inhibits programmed cell death (apoptosis), has recently been found to be cyclically expressed in human endometrium. In order to investigate its role in endometrial hyperplasia and neoplasia, bcl-2 expression was studied in 25 cases of endometrial carcinoma and 20 cases of endometrial hyperplasia (eight simple, two complex, and ten atypical hyperplasias). Uniform intense cytoplasmic bcl-2 expression was found in all cases of non-atypical hyperplasia, and less strong positivity in eight out of ten cases of atypical hyperplasia. In well-differentiated carcinomas, nine out of ten showed weak to moderate bcl-2 expression, whereas six out of seven poorly differentiated carcinomas were bcl-2-negative. Moderately differentiated tumours were an intermediate group, with six out of eight being positive. Widespread localization of bcl-2 protein to the chromosomes of dividing cells was also demonstrated, regardless of cytoplasmic bcl-2 expression, with rare staining of interphase nuclei. Our findings suggest a role for bcl-2 in the natural history of endometrial neoplasia and studies are needed to determine its usefulness as a prognostic marker. The finding of bcl-2 localization to chromosomes has important implications for its mode and site of action.

[Effect of cypermethrin on some reproductive factors in Culex (C) quinquefasciatus Say 1823]. / Efecto de la cipermetrina sobre algunos factores reproductivos en Culex (C) quinquefasciatus Say 1823.

An experiment was carried otu with a Culex quinquefasciatus strain with resistance genes called "Quibú", and with a susceptible strain provided by the WHO; they were pressured with different lethal doses of cypermetrine. Time-mortality regression lines of the 2 strains were estimated following WHO methodology and the "Quibú" strain showed tolerance to the insecticide. TL30 and TL70 were selected to test their effect on fecundity, fertility, sexual index, and egg eclosion time. A significant reduction in fecundity and fertility was observed in the "Quibú" strain after it was pressured, no effect was detected on the sexual index and egg eclosion time in this strain.

The developmental toxicity of inhaled methanol in the CD-1 mouse, with quantitative dose-response modeling for estimation of benchmark doses.

The developmental toxicity of the alternative motor vehicle fuel methanol was assessed in mice by the inhalation route. Pregnant CD-1 mice were exposed to 1,000, 2,000, 5,000, 7,500, 10,000, or 15,000 ppm methanol for 7 hr/day on days 6-15 of gestation. Sham-exposed controls were exposed to filtered air under similar conditions. Additional control groups were left in their home cages either unhandled or food-deprived for 7 hr/day to match the food deprivation experienced by the exposed mice. Dams were observed twice daily and weighed on alternate days during the exposure period. Blood methanol concentrations were determined in some mice on gestation days 6, 10, and 15. On day 17, the remaining mice were weighed and killed and the gravid uteri removed. Implantation sites, live and dead fetuses and resorptions were counted, fetuses were examined externally and weighed as a litter. Half of each litter was examined for skeletal morphology and the other half of each litter was examined for internal soft tissue anomalies. One dam died in each of the 7,500, 10,000, and 15,000 ppm methanol exposure groups, but no dose-response relationship was evident for maternal death. The sham-exposed and food-deprived controls as well as all methanol exposed dams gained less weight than did unexposed dams fed ad libitum, but methanol did not exacerbate this effect. Significant increases in the incidence of exencephaly and cleft palate were observed at 5,000 ppm and above, increased embryo/fetal death at 7,500 ppm and above (including an increasing incidence of full-litter resorptions), and reduced fetal weight at 10,000 ppm and above. A dose-related increase in cervical ribs or ossification sites lateral to the seventh cervical vertebra was significant at 2,000 ppm and above. Thus, the NOAEL for the developmental toxicity in this study was 1,000 ppm. A log-logistic dose response model was applied to the incidence data for exencephaly, cleft palate, resorption and cervical rib, and maximum likelihood estimates (MLEs) and benchmark dosages (BDs, the lower 95% confidence interval of the MLEs) corresponding to 1% and 5% added risk above background were calculated. The MLE for 5% added combined risk of having either exencephaly or cleft palate or being resorbed was 3667 ppm, and the corresponding BD was 3,078 ppm. For cervical rib, the 5% added risk values for the MLE and BD were 824 and 305 ppm, respectively. The BDs for 1% added risk were 1915 ppm for exencephaly, cleft palate or resorption, and 58 ppm for cervical rib.(ABSTRACT TRUNCATED AT 400 WORDS)

Desmoid tumour in thoracotomy scar 5 years after excision of a left giant atrial appendage aneurysm in female with a family history of Gardner's syndrome.

A very large desmoid tumour extensively involving the chest wall and the left anterior abdominal wall is described in a patient with a family history of Gardner's syndrome. The desmoid arose at the site of a thoracotomy scar due to the removal of a large aneurysm of the left atrial appendage five years before. Both a plastic surgeon and a thoracic surgeon were required to remove the tumour. Aneurysmal dilatation of the left atrium is extremely rare and has not been reported in association with Gardner's syndrome before.

Effect of inhaled methanol on pituitary and testicular hormones in chamber acclimated and non-acclimated rats.

Two experiments were conducted in which the acute effects of inhaled methanol on serum hormones associated with reproductive function in the male rat were evaluated. In the first experiment, rats exposed to methanol (0, 200, 5000 and 10,000 ppm) for 6 h were killed at the end of the exposure period (6 h) or the following morning (24 h). Also, because the process of exposure itself could modify neuroendocrine function, the effect of the handling associated with placing the rat in the exposure chamber was evaluated further by dividing the exposed animals into acclimated (2 weeks of prior handling) and non-acclimated groups. At 6 h, an effect of prior handling was noted in the sham-exposed rats, with serum luteinizing hormone (LH) of the non-acclimated group being greater than that of the acclimated group. Serum LH concentrations were altered by methanol exposure, but the direction of change and the exposure level at which an effect was noted differed between the acclimated and non-acclimated rats. Methanol (5000 ppm) reduced serum LH in the non-acclimated animals, while 10,000 ppm increased LH in the acclimated rats. Follicle stimulating hormone (FSH) and testosterone were unchanged by methanol in rats killed at 6 h. Thus, this experiment did not confirm earlier reports that exposure to 200 ppm for 6 h reduced serum testosterone. At 24 h, an effect of prior handling was still present in the hormonal measures, with serum and interstitial fluid testosterone concentrations being greater in the non-acclimated rats. Also, there was a dose x handling interaction with methanol exposure inducing an increase in serum testosterone in the non-acclimated rats (up to 5000 ppm) and a decrease in the acclimated rats (up to 10,000 ppm). In the second experiment, groups of acclimated and non-acclimated rats were exposed to 0 or 5000 ppm methanol for 1, 2 and 6 h and killed immediately after removal from the chamber. Serum LH, testosterone and FSH values were not different in sham- vs methanol-exposed rats at any time point. As in experiment 1, an effect of prior handling was noted. In general, the concentrations of these hormones and serum prolactin in the non-acclimated rats were greater than those observed for acclimated rats. Methanol exposure resulted in increased prolactin concentrations under both handling conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

High-performance liquid chromatographic assay of biphenyl metabolism by hepatocytes cultured in an embryo/hepatocyte co-culture medium.

A high-performance liquid chromatographic method has been modified for the evaluation of both Phase I and II metabolism of biphenyl by hepatocytes maintained in an embryo/hepatocyte co-culture medium. Extracts of the media, before and after hydrolysis of conjugates, are directly injected onto the HPLC and the major hydroxylated metabolites plus unmetabolized biphenyl are detected by fluorescence after separation under gradient or isocratic conditions. The method is almost free of interferences and is relatively simple and rapid. In the case of the monohydroxylated derivatives, the minimum media concentrations which can be measured are 7 to 20 nM (0.07 to 0.2 pmol on-column). Recoveries from culture medium to which known amounts of biphenyl and metabolites had been added were quantitative (90-103%) and the reproducibility good (interassay CV less than 5%). The assay was applied to cultures of hepatocytes derived from rabbit and from phenobarbital induced and noninduced rat.