Synthetic Organotellurium Compounds Sensitize Drug-Resistant Candida albicans Clinical Isolates to Fluconazole.

Invasive Candida albicans infections are a serious health threat for immunocompromised individuals. Fluconazole is most commonly used to treat these infections, but resistance due to the overexpression of multidrug efflux pumps is of grave concern. This study evaluated the ability of five synthetic organotellurium compounds to reverse the fluconazole resistance of C. albicans clinical isolates. Compounds 1 to 4, at <10 µg/ml, ameliorated the fluconazole resistance of Saccharomyces cerevisiae strains overexpressing the major C. albicans multidrug efflux pumps Cdr1p and Mdr1p, whereas compound 5 only sensitized Mdr1p-overexpressing strains to fluconazole. Compounds 1 to 4 also inhibited efflux of the fluorescent substrate rhodamine 6G and the ATPase activity of Cdr1p, whereas all five of compounds 1 to 5 inhibited Nile red efflux by Mdr1p. Interestingly, all five compounds demonstrated synergy with fluconazole against efflux pump-overexpressing fluconazole-resistant C. albicans clinical isolates, isolate 95-142 overexpressing CDR1 and CDR2, isolate 96-25 overexpressing MDR1 and ERG11, and isolate 12-99 overexpressing CDR1, CDR2, MDR1, and ERG11 Overall, organotellurium compounds 1 and 2 were the most promising fluconazole chemosensitizers of fluconazole-resistant C. albicans isolates. Our data suggest that these novel organotellurium compounds inhibit pump efflux by two very important and distinct families of fungal multidrug efflux pumps: the ATP-binding cassette transporter Cdr1p and the major facilitator superfamily transporter Mdr1p.

Lack of genotoxicity in Astyanax bimaculatus and Oreochromis niloticus of 17α-methyltestosterone used in fish hatcheries to produce male monosex populations.

17α-Methyltestosterone (MT) is widely used in fish hatcheries of many countries to produce male monosex populations. Its genotoxic risk to fish species is not well known and studies in other in vivo models are still inconclusive. MT was tested for genotoxicity in the fish species Oreochromis niloticus (tilapia), a target species, and Astyanax bimaculatus (lambari), a native non-target species. Genotoxicity was evaluated by the micronucleus test (MN), nuclear abnormalities (NA), and comet assay using peripheral erythrocytes of both species after a 96-h exposure to MT at concentrations of 0.01, 0.1, and 1.0 mg/L in the water. At the lowest exposure level of 0.01 mg/L, MT induced MN in both species and NA only in O. niloticus. These effects were not observed in the comet assay. Chromatographic analysis of water samples collected from aquariums at the beginning and end of each experiment showed that MT was consumed during the 96-h exposure. At the highest level of exposure (1.0 mg/L), 81.69% of the hormone was consumed during the exposure period. The chromatogram showed that at the lowest concentration level of 0.01 mg/L, 99.56% MT was consumed by the end of the exposure period. Thus, exposure to MT did not cause genotoxicity in either fish species.

Early malnutrition favours heavy ethanol intake in weaning rats without long-lasting effects.

INTRODUCTION: Although food restriction is well known to increase ethanol intake, the subject has not been extensively studied in developing animals which could be more vulnerable to long-lasting effects. Therefore, the aim of this study was to show some findings concerning this subject. MATERIALS AND METHODS: Food restriction was used to produce malnutrition either during lactation (lactating dams food restricted 60%) or after weaning (pups food restricted 60%). At weaning, day 25, males were assigned to one of the following groups: C, food ad libitum throughout the experiment - control group; MW, malnourished only after weaning; ML, malnourished only during lactation period; and MLW, malnourished throughout the experiment, during lactation and after weaning. All rats were kept isolated in cages in which they could choose to drink either a 10% ethanol solution or tap water (from days 25 to 45). Re-exposure to this model was performed on day 49. Between exposure and re-exposure, rats drank tap water for 4 days. RESULTS: There was a significant effect of malnutrition during lactation, up to day 35, with heavy drinking patterns (ethanol intake day 2: C, 8 g/kg; MW, 9 g/kg; ML, 19 g/kg; and MLW, 22 g/kg). This heavy drinking pattern lasted until the recovery of body weight. Food restriction after weaning had significant effects after 14 days, when a statistically significant decrease in body weight occurred (body weight day 39: C, 147.8 g; MW, 98.5 g). Only rats which were persistently malnourished (MLW and MW) drank ethanol more significantly than their ad libitum-fed counterparts during the re-exposure period (ethanol intake: malnourished, 5 g/kg; and well-nourished, 2.5 g/kg). Adulteration of the ethanol solution with quinine (0.1 g/l) precluded the effect of malnutrition. CONCLUSIONS: Malnutrition during early development had no long-lasting effects on ethanol consumption. In addition, malnutrition increased ethanol consumption as long as it kept body weight low, which was apparently more significant in young animals.

Effect of two different types of malnutrition on the rate of elimination of ethanol in rats.

Rats were fed "3% casein" or a "calorie deficient" diet, in the form of commercial pellet diet (SDS) at 50% of the amount consumed by the control group, which was fed SDS pellets ad libitum. Both of the deficient groups showed failure of weight gain in comparison with the control group. Blood levels of ethanol were measured for 3 hr after intraperitoneal injection of 1 or 1.5 g/kg at 15, 29 and 36 days after commencement of the diet. In addition the calorie deficient group was studied immediately after feeding as well as in the fasting state. Blood levels of ethanol were measured and the apparent volume of distribution and rate of removal of ethanol from the blood were calculated. A rate of ethanol metabolism/g of liver was derived. The rate of removal of ethanol was markedly decreased in the 3% casein group to less than half of control values. Three hours after injection of ethanol circulating levels were less than 50 mg/100 ml in the control and calorie deficient groups but over 200 mg/100 ml in the group fed protein deficient diets. There were no major changes in volume of distribution and the only explanation for the finding is that there is a failure of ethanol metabolism in the rats fed the low protein diet. The implication is that protein deficient human populations who often consume considerable quantities of ethanol may have a high level of tissue exposure to ethanol though the rate of metabolite formation may be low.

Developmental toxicity of in utero exposure to toluene on malnourished and well nourished rats.

The aim of the present study was to investigate the effects of toluene on fetal development in well nourished and malnourished rats. Long-term behavioural consequences after in utero exposure were also studied. Toluene (1.2 g/kg s.c.) was administered daily to well nourished and to malnourished (food restricted to 50% of ad libitum intake) pregnant rats, during the second (8-15 days) or the third week of pregnancy (14-20 days). Offspring were evaluated for malformations, development of the skeleton, prenatal growth of the brain and liver, postnatal growth and long lasting behavioural effects. In utero exposure to toluene during the third week of pregnancy resulted in low body weight at birth, which persisted in the male offspring into adulthood. Malnutrition increased fetal susceptibility to the effects of toluene as indicated by evaluation of the development of the skeleton. Behavioral tests performed when the pups were 30 and 90 days old showed effects of in utero malnutrition (increased ambulation and worse performance in a shuttle box), but no behavioural effects related to toluene exposure were detected. These data indicate that in utero exposure to toluene can have long lasting effects on body growth and that maternal malnutrition increases the risk for toluene fetotoxicity.

Neurobehavioural development of the golden hamster.

The aim of this study was to establish a developmental profile for the golden hamster by using a systematic sequence of test procedures. One experimentally naive litter was tested each day from 0 to 25 days of postnatal age. The appearance of developmental landmarks (physical features and reflexes), spontaneous behaviour in an open field, homing behaviour and rota rod performance were studied. Infant mortality through infanticide was recorded in undisturbed and tested hamsters. The results indicated that most of the tests employed in the present study can be applied usefully in the evaluation of the neurobehavioural development of the golden hamster. The developmental profile for this species is described in detail. In comparison to rats and mice, hamsters display accelerated development of a number of characteristics, most notably incisor eruption and vaginal opening. Infanticide, the most troublesome problem in studies in which hamster litters must be disturbed, did not occur after day 3. As most reflexes and sensory abilities develop after this age, hamster pups can be used successfully in behavioural teratology evaluation.

Can calories from ethanol contribute to body weight preservation by malnourished rats?

Our objective was to compare the use of calories from ethanol by well-nourished and malnourished rats in terms of body weight. Female Wistar rats weighing 170-180 g at the beginning of the study were used. The animals were divided into two groups (N = 12 each): group W received water ad libitum and group E an ethanol solution ad libitum as the only source of liquid throughout the experiment. The concentration of ethanol was increased weekly from 0 to 5, 10, 20 and 40% (v/v). In the well-nourished phase (A), all rats received food ad libitum (AW and AE). Ethanol treatment (AE) was then interrupted and water was offered to both groups. After 2 weeks both AW and AE rats were submitted to food restriction (50% of group AW food consumption), thus initiating the malnutrition phase (M). Liquid was offered as described before to the same W (MW) and E (ME) groups. The weight gain during the 1-week treatment of AE rats was similar to that of AW animals only when AE rats received the 5% (v/v) ethanol solution (9.16 vs 10.47 g). Weight loss was observed after exposure to 10% ethanol (P < 0.05) in spite of maintenance of caloric intake. Malnourished rats presented weight loss, which was attenuated by ethanol intake up to the 20% (v/v) solution and was related to an increased caloric offer. This effect was not observed with the 40% ethanol solution (-9.98 g). These data suggest that calories from ethanol were used to maintain body weight up to the concentration of 10% (v/v) (well-nourished) and 20% (v/v) (malnourished) and that ethanol has a toxic profile which depends on nutritional status.

Ethanol elimination by rats as a function of reproductive state, gender and nutritional status.

Alcohol elimination was studied in rats of different ages, reproductive states and nutritional deprivation, with the following results: 1) blood levels of ethanol 180 min after a single dose of 1.5 g/kg, ip were significantly higher in adult male (74 days old, N = 5) than in young male rats (34 days old, N = 5): 92.4 +/- 8.4 vs 6.8 +/- 3.4 mg/100 ml, means +/- SD, respectively; 2) when male rats were given a low protein diet for 48 h, blood ethanol levels after a single dose were significantly increased in young males (38.6 +/- 14.6 mg/100 ml) but no effect after a single dose was found in the same animals at an older age (93.2 +/- 5.0 mg/100 ml); 3) blood levels in female rats were higher than in young males both in the virgin and pregnant states, but during lactation a significant drop in blood levels of ethanol was observed. Blood levels of ethanol (mg/100 ml) 180 min after a single dose of 1.5 g/kg, ip, in females, were: virgin (N = 6): 44.9 +/- 16.1, pregnant (N = 5): 40.0 +/- 10.4, lactant (N = 5) 8.8 +/- 5.8. This difference between virgin and pregnant and lactant rats was not related to changes in ADH activity which did not differ between groups. The present study indicates that in male rats the effect of a short-term protein deprivation on ethanol elimination is dependent on the age of the animal. In females, reproductive state is an important factor in determining ethanol elimination.

Effects of toluene exposure during gestation on neurobehavioral development of rats and hamsters.

Pregnant rats and hamsters were exposed to toluene vapor (800 mg/m3) 6 h daily from gestation days 14 to 20, and 6 to 11, respectively. Growth, neuromotor development and performance of the offspring in behavioral tasks were assessed. In rats, toluene exposure increased the number of litters with low birth weight pups. Male rat offspring exposed to toluene displayed shorter latencies than male controls to choose one side of a T maze in a spontaneous alternation test. Hamsters exposed to toluene performed worse in a rotating rod test. These results confirm toluene fetotoxicity in rats and suggest an effect on exploratory behavior which may be related to hormonal changes in early life. Neuromotor effects of exposure of hamsters to toluene in utero deserve further investigation.

Effects of ethanol and malnutrition on rat neuromotor development.

The objective of the present study was to determine whether there is a synergistic effect of malnutrition and ethanol exposure on neuromotor development. Ethanol (E) (6 g/kg) or sucrose (S) (isocaloric to ethanol) was administered by gavage to ad libitum-fed (A) and malnourished (M) pregnant rats on days 18, 19 and 20 of pregnancy. Malnutrition was produced by food restriction to 50% of control intake. At birth, the offspring were weighed and transferred to surrogate mothers. Performance in the rim-escape test and on the rotating rod were evaluated on days 19 and 28 of life, respectively. Development of the adult swimming pattern was also studied. The results indicated that: 1) malnutrition alone decreased birth weight (g) significantly (AE, 5.56 +/- 0.36; AS, 6.31 +/- 1.05; ME, 4.81 +/- 0.73; MS, 5.23 +/- 0.57); 2) a synergistic interaction between alcohol exposure and malnutrition was observed only in the rim escape test (percent of falling rats: AE, 9; AS, 5; ME, 24; MS, 5); 3) only malnutrition retarded development of swimming; 4) malnourished dams gained more weight (g) than controls during treatment with ethanol (AE, 2.6 +/- 8.4, N = 6; AS, 3.1 +/- 8.4, N = 4; ME, 23.0 +/- 6.3, N = 7; MS, 29.0 +/- 9.0, N = 8). These results indicate a possible synergistic action between malnutrition and ethanol on neuromotor development and point to the importance of ethanol as a calorie source for malnourished animals.

Postnatal development of rats exposed to fluoxetine or venlafaxine during the third week of pregnancy.

The aim of the present study was to compare the toxic effects of fluoxetine (F) (8 and 16 mg/kg) and venlafaxine (V) (40 and 80 mg/kg) administered during the third week of pregnancy on early development of rats. Both antidepressants were administered by gavage on pregnancy days 15 to 20 to groups of 10 to 12 animals each. Duration of gestation, food and water consumtion, number of live pups and birth weight were recorded. Litters were culled to six pups at birth (day 1) and followed for growth until weaning (day 25). On day 60, a male and a female from each litter were injected with the 5-HT1 agonist, 5-methoxy-N,N-dimethyltryptamine (6 mg/kg, i.p.) and the serotonergic syndrome was graded. Fluoxetine but not venlafaxine reduced the duration of pregnancy when compared to the control (C) group (F = 21.1 days and C = 21.6 days, mean, P < 0.02: maximum = 22 days and minimum = 21 days in both groups). The highest doses of both fluoxetine, 16 mg/kg (F16), and venlafaxine, 80 mg/kg (V80), reduced the food intake of pregnant rats, resulting in different rates of body weight gain during treatment (from pregnancy day 15 to day 20): F16 = 29.0 g, V80 = 28.7 g vs C = 39.5 g (median). Birth weight was influenced by treatment and sex (P < 0.05; two-way ANOVA). Both doses of fluoxetine or venlafaxine reduced the body weight of litters; however, the body weight of litters from treated dams was equal to the weight of control litters by the time of weaning. At weaning there was no significant difference in weight between sexes. There was no difference among groups in number of live pups at birth, stillbirths, mortality during the lactation period or in the manifestation of serotonergic syndrome in adult rats. The occurrence of low birth weight among pups born to dams which did not show reduced food ingestion or reduction of body weight gain during treatment with lower doses of fluoxetine or venlafaxine suggests that these drugs may have a deleterious effect on prenatal development when administered during pregnancy. In addition, fluoxetine slightly but significantly affected the duration of pregnancy (about half a day), an effect not observed in the venlafaxine treated groups.

Protein-energy malnutrition increases teratogenicity of hypervitaminosis A in rats.

The present study was designed to investigate the embryo-fetotoxicity of vitamin A in protein-energy malnourished animals. Retinyl palmitate (66, 99 and 132 mg/kg) suspended in corn oil was given by gavage to well-nourished and malnourished rats from gestational days 8 to 10 and cesarean sections were performed on day 20. All fetuses were weighed and examined for malformations before being prepared for skeletal evaluation. The proportion of malformed fetuses was higher in the malnourished group at each one of the three dose levels. The data indicate that malnourished animals are more susceptible to the toxic effects of retinyl esters.

Ethanol pharmacokinetics in lactating women.

Experimental studies in rats have demonstrated that lactating females have blood ethanol levels five times lower than those observed in non-lactating rats. The purpose of the present study was to verify if this phenomenon also occurs in human beings. Five lactating (L) and five control (C) women received, after formal agreement to the experimental procedure, 0.4 g/kg of ethanol as vodka (Stolichnaya, USSR), between 9:00 and 10:15 a.m. Blood and milk samples were collected 10, 20, 40, 60, 90, 150 and 180 min after ethanol ingestion. Ethanol levels in blood and milk were measured by gas chromatography using the head space technique. Results indicated that: time to reach maximal blood levels was significantly longer in the L group (L: 48.0 +/- 10.9, C: 31.2 +/- 16.4 min, means +/- SD), area under the curve was smaller when group L was compared to group C (L: 3821.5 +/- 1240.5, C: 5154.8 +/- 1313.7 mg% x min, means +/- SD), ethanol blood levels (mg/dl) at 150 and 180 min were significantly lower in the L group (150: L, 10.5 +/- 5.6; C, 18.7 +/- 6.8; 180: L, 3.9 +/- 2.8; C, 13.2 +/- 6.4, means +/- SD). Concentration of ethanol in milk was similar to concentration in blood. These results indicate the importance of lactation for ethanol pharmacokinetics and raise questions about the pharmacokinetics of other drugs ingested by lactating women.

Neurobehavioral development of rats exposed to toluene through maternal milk.

Organic solvents have been detected in the milk of workers in the rubber industry exposed during gestation to a mixture of solvents at average concentrations lower than the currently accepted occupational limit of exposure (100 ppm). The objective of the present study was to determine if exposure of rat offspring to toluene during lactation, through maternal milk, would affect the developing brain. Three month old, lactating Wistar rats were injected with toluene (1.2 g/kg, sc, N = 10) daily from lactation day 2 (day of delivery = day 1) to day 21. Controls (N = 9) were injected with the vehicle (corn oil). Offspring (7 pups per liter) were evaluated for neurosomatic development and exploratory behavior before weaning and behavior in the open field. A second group of toluene-treated rats (N = 6) and controls (N = 6) was used to evaluate behavior of the offspring in the open-field on day 35 and performance in a shuttle box in adulthood. Toluene levels in blood and milk after a single 1.2 g/kg sc injection were studied in a third group of rats on lactation day 10. Toluene levels in milk 4 h after a single injection (10.3 +/- 6.2) were 5 times higher than in blood (2.1 +/- 0.8). No effects of treatment on offspring development or on any of the behavioral tests were observed. Sex differences were observed in open-field behavior and performance in the shuttle box. The present results suggest that exposure of pups to high concentrations of toluene through maternal milk does not result in blood levels high enough to affect growth or development.

Prenatal and postnatal depression among low income Brazilian women.

Postnatal depression is a significant problem affecting 10-15% of mothers in many countries and has been the subject of an increasing number of publications. Prenatal depression has been studied less. The aims of the present investigation were: 1) to obtain information on the prevalence of prenatal and postnatal depression in low income Brazilian women by using an instrument already employed in several countries, i.e., the Edinburgh Postnatal Depression Scale (EPDS); 2) to evaluate the risk factors involved in prenatal and postnatal depression in Brazil. The study groups included 33 pregnant women interviewed at home during the second and third trimesters of pregnancy, and once a month during the first six months after delivery. Questions on life events and the mother's relationship with the baby were posed during each visit. Depressed pregnant women received less support from their partners than non-depressed pregnant women (36.4 vs 72.2%, P < 0.05; Fisher exact test). Black women predominated among pre- and postnatally depressed subjects. Postnatal depression was associated with lower parity (0.4 +/- 0.5 vs 1.1 +/- 1.0, P < 0.05; Student t-test). Thus, the period of pregnancy may be susceptible to socio-environmental factors that induce depression, such as the lack of affective support from the partner. The prevalence rate of 12% observed for depression in the third month postpartum is comparable to that of studies from other countries.

Neurobehavioral study of the effect of beta-myrcene on rodents.

Tea prepared from lemongrass (Cymbopogon citratus) is used for its supposed anxiolytic, hypnotic and analgesic properties in Brazilian folk medicine. beta-Myrcene, a major constituent of lemongrass, produces analgesia in rodents but there is some controversy about whether this action is central or peripheral or both. Rats and mice received beta-myrcene, 1 g/kg po in corn oil, or corn oil alone 1 h before being evaluated for a series of responses which included exploratory and emotional behavior, anxiolytic activity in a plus maze and inhibition of conditioned avoidance. No evidence was demonstrable for an effect of beta-myrcene on any of these behaviors. Similarly, beta-myrcene had no protective effect on pentylenetetrazol (PTZ)-induced seizures in mice. These data suggest that beta-myrcene has no benzodiazepine-like anxiolytic activity and that an activity on the central nervous system (antidepressive or antipsychotic) is unlikely. Despite the negative results of this study, folk use of lemongrass tea may still be justified by its analgesic properties.

Behavioral toxicity of increasing doses of ethanol in malnourished rats.

In order to verify the toxicity of ethanol in malnourished rats, the following procedure was applied to two groups of rats (n = 12 each): group W: drinking water ad libitum and group E: drinking only an ethanol solution in a gradual dosage (0, 5, 10, 20 and 40% v/v). In the well-nourished phase, all rats received food ad libitum (AW and AE). Ethanol treatment (AE) was interrupted for two weeks. Rats from both AW and AE groups were submitted to food restriction (50% of AW consumption)--malnourished phase (M)--and liquid was offered as described before. Signs of ethanol intoxication were recorded daily. Ethanol withdrawal symptoms and the open-field test were performed 24 h after the well-nourished and malnourished phases. Rats were sacrificed for macroscopic evaluation of liver, spleen, thymus and biochemical analyses of the blood (hematocrit, hemoglobin, proteins and albumin). Malnourished rats showed more signs of ethanol intoxication and withdrawal. In the open-field test, malnourished rats ambulated more and made more rearing up. This effect of malnutrition was not observed during ethanol withdrawal. Consumption of ethanol decreased the levels of hemoglobin, hematocrit and total proteins. Data suggested that toxic profile of ethanol was dependent on nutritional status.

Genetically selected winner and loser rats: what was selected?

Throughout the 6--12th generation, genetically selected winner and loser rats in the straight runway test, were studied, in relation to weight, open field behavior, behavioral responses to footshock and adrenocortical response following stimulation. The results showed that the Loser Runway Strain (LRS) when compared to the Winner Runway Strain (WRS), were (1) lighter in weight, (2) defecated less, ambulated more and showed higher frequency of rearing-up when submitted to an open field (3) defecated less and jumped more in reaction to footshock and (14) had a higher rise of corticosterone levels following handling or footshock. These differences between WRS--LRS are the same found between male-female rats. This conclusion does not favor the validity of the runway test as a social measure, and suggests that WSR--LRS were selected according to male-female characteristics instead of a winning or losing trait.

Developmental, behavioral, and pharmacological characteristics of rat offspring from mothers receiving ethanol during gestation or lactation.

Ethanol solution (10 or 20% v/v) sweetened with .4% saccharin was given to female rats as the only source of fluid. In the 1st experiment the administration was throughout the gestation period. Developmental, behavioral, and pharmacological tests were performed with the offspring. Litters born from females of the experimental group showed a decrease in the mortality rate induced by pentylenetetrazol, in comparison with either pair-fed controls or an ad libitum control group. No other differences were detected. In the 2nd experiment the administration was throughout the lactation period. Pups raised by lactating mothers receiving ethanol showed a significant decrease in weight gain. Also, the maternal behavior of the ethanol-treated mothers, measured by nest-building and retrieval activities, showed a significant decrease when compared to pair-fed controls.