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PubMed2006

Spatial and temporal distribution of benthic macroinvertebrates in a Southeastern Brazilian river.

Benthic macroinvertebrate assemblages are structured according to physical and chemical parameters that define microhabitats, including food supply, shelter to escape predators, and other biological parameters that influence reproductive success. The aim of this study is to investigate spatial and temporal distribution of macroinvertebrate assemblages at the Macaé river basin, in Rio de Janeiro state, Southeastern Brazil. According to the "Habitat Assessment Field Data Sheet--High Gradient Streams" (Barbour et al., 1999), the five sampling sites are considered as a reference condition. Despite the differences in hydrological parameters (mean width, depth and discharge) among sites, the physicochemical parameters and functional feeding groups' general structure were similar, except for the less impacted area, which showed more shredders. According to the Detrended Correspondence Analysis based on substrates, there is a clear distinction between pool and riffle assemblages. In fact, the riffle litter substrate had higher taxa in terms of richness and abundance, but the pool litter substrate had the greatest number of exclusive taxa. A Cluster Analysis based on sampling sites data showed that temporal variation was the main factor in structuring macroinvertebrate assemblages in the studied habitats.

Animals↗

PubMed1999

Safety evaluation of phytosterol esters. Part 3. Two-generation reproduction study in rats with phytosterol esters--a novel functional food.

Phytosterol esters (PE) are intended for use as a novel food ingredient with plasma cholesterol lowering activity which works by inhibiting the absorption of cholesterol from the gut. Although PE are naturally present in the normal diet, the levels are insufficiently large to ensure lowering of plasma cholesterol levels. Therefore PE may be added to spreads to achieve the desired cholesterol lowering activity. As part of an extensive programme of safety evaluation studies a two-generation reproduction study has been conducted in Wistar rats, in which the possible effect of PE on male and female reproductive performance and on the growth and development of the offspring was studied. Rats were fed diets containing PE at levels of 0, 1.6, 3.2 and 8.1% (w/w) PE over two successive generations, and a wide range of reproductive and developmental parameters, including sexual maturation parameters and oestrous cycle length, were determined. Macroscopic and microscopic examinations were conducted including a histological examination of selected organs from F1- and F2-weanlings and from F0- and F1-parental animals. Daily clinical observations did not reveal any unusual findings. In both generations, no effects of PE were observed on pup mortality (calculated on litter basis), precoital time, mating index, male and female fertility index, female fecundity index, gestation index, duration of gestation, number of females with stillborn pups, post-implantation loss and pup development. Furthermore, PE had no effect on sexual maturation parameters (preputial separation and vaginal opening) and oestrous cycle length. In addition, there were no dose-related effects on selected organs following histological examination. In conclusion, dietary administration of up to 8.1% PE (equivalent to a dose of 2.5 to 9.1 g PE/kg body weight/day, dependent on the period of the study) during two generations had no effect on reproduction of parental F0- and F1-generation Wistar rats, nor on the development of the F1- and F2-pups, nor on the sexual maturation of the F1-weanlings. Therefore, a nominal dietary PE concentration of 8.1% (equivalent to a dose of 2.5-9.1 g PE/kg body weight/day or 1.54-5.62 g phytosterol/kg body weight/day dependent on the period of the study) was considered to be the no-observed-adverse-effect level following daily oral administration of PE for two successive generations.

Animals↗

PubMed2003

Effects of testosterone undecanoate as a male contraceptive candidate on rat immunological features.

Testosterone undecanoate (TU) is under phase III clinical trial as a hormonal male contraceptive in China. Sex hormones can modulate the immune system. Female hormonal contraceptives may affect SIV/HIV-1 transmission. To evaluate the safety of TU and to understand whether long-term use of TU for a male contraceptive affects users' immunological features, adult male rats were treated for a 32-week TU-treated phase at the dose of 20 mg TU/kg body weight and a 24-week recovery phase. The reproductive and immunological parameters of 4-6 rats in each subgroup were examined at the stated time point. The mean sperm count and viability in the treated rats were significantly suppressed (p < 0.01). In the TU-treated group: the mean blood leukocyte and lymphocyte counts; the proliferation indexes of T cells from peripheral blood mononuclear cells (PBMC) and spleen; and, of B cells from spleen, as well as the mean counts of blood T, NK, and B cells decreased in comparison with those of control group. These decreases were not significant (p > 0.01). Similarly, the mean serum IgM, IgG, and IgA levels and complement activity in TU-treated rats were lower than those in control group (p > 0.01), and the changes in the antibody levels of the examined genital secretions were not significant (p > 0.01). The changes in the thickness of urethra epithelium, and in secretory component (SC) expression in genitals were not observed in the treated group. These results demonstrated that long-term supraphysiological TU injection did not obviously affect the examined rat immunological parameters.

Animals↗

PubMed2004

[Population-genetic structure of beaver (Castor fiber L., 1758) communities and estimation of effective reproductive size Ne of an elementary population].

The absence of panmixia at all hierarchical levels of the European beaver communities down to individual families implies a complex organization of the population-genetic structures of the species, in particular, a large intergroup component of gene diversity in the populations. Testing this assumption by analysis of 39 allozyme loci in the communities of reintroduced beaver from the Vyatka river basin (Kirov oblast) has shown that only the beaver colonies exhibit high intergroup gene diversity (Gst = 0.32) whereas this parameter is much lower when estimated among beaver groups from individual Vyatka River tributaries and among localities of one of the tributaries (0.07 and 0.11, respectively). The data suggesting genetic heterogeneity among individual settles within colonies have been obtained. The factors affecting the structure of the beaver communities of the lower hierarchical ranks are considered: the common origin, founder effect, selection, gene drift, assortative mating, and social and behavior features of the species. The conclusion is drawn that the founder effect could be the primary factor of population differentiation only at the time of their formation. The heterogeneity among colonies and among settles is maintained largely by isolation of colonies from one another. The strong interspecific competition for food resources, which is behaviorally implemented in the species at the level of minimal structural units (individual settles) creates a profound and unique population-genetic subdivision of the species. These results substantiate the suggestion that an elementary population (micropopulation) of European beaver is a colony, i.e., a set of related settles of different types. Based on ecological and genetic parameters, the effective reproductive size Ne of the minimum beaver population was estimated to be equal to three animals. This extremely low value of effective reproductive population size largely explains the high tolerance of European beaver to inbreeding and striking viability of the species, which from the early 19th century has been for more than hundred years on the brink of survival in the condition which would made any other mammalian species vanish from the Earth.

Animals↗

PubMed1992

Effects of amaranth on F1 generation mice.

The color additive, amaranth, was given in the diet to provide dietary levels of 0 (control), 0.03, 0.09 and 0.27%, from 5 weeks of age in F0 generation mice to 9 weeks of age in F1 generation mice, and some reproductive, developmental and behavioral parameters were measured. There was no effect on the parameters of litters, litter size, pup weight and litter weight. The body weight of pups during the lactation period in the treatment groups increased less significantly, and the survival index at postnatal day (PND) 21 of the amaranth 0.27% group was reduced. Developmental parameters, direction of swimming on PND 4 in male pups and olfactory orientation in each sex were significantly reduced in the treatment groups. The dose levels of amaranth in this study influenced some reproductive, developmental and behavioral parameters in mice.

Amaranth Dye↗

PubMed2003

Inhibin B and ovarian function after total abdominal hysterectomy in women of reproductive age.

The aim of this prospective study was to assess ovarian function using clinical and endocrine parameters in women of reproductive age who underwent total abdominal hysterectomy. Sixty-one women, aged </= 40 years, were allocated into two groups: group 1, consisting of 31 patients who had hysterectomy, and group 2, consisting of 30 normal women. Inclusion criteria were normal ovarian function at baseline, normal body weight, no hormonal diseases and basal follicle stimulating hormone (FSH) level of < 15 mIU/ml. FSH, luteinizing hormone (LH), estradiol and inhibin B levels as well as maturation value (MV) were measured by vaginal cytology on three occasions: baseline, and 6 and 12 months after hysterectomy. Analysis of variance, the Friedman test, Mann-Whitney test and t -test statistics were employed to compare the two groups. At baseline the groups were homogeneous. At months 6 and 12, hysterectomized women showed decreased median values of inhibin B, increased median values of estradiol (p < 0.05), unchanged median values of FSH and LH, and decreased median values of MV (p < 0.05). In the hysterectomy group, 12.9% (4/31) of the patients had FSH levels of > 40 mIU/ml, estradiol of < 20 pg/ml and inhibin B of < 5 ng/ml, compatible with ovarian failure. In the control group, all the parameters studied remained unchanged. These results suggest that total abdominal hysterectomy accelerates the decline in ovarian function in women of reproductive age.

Adult↗

PubMed2004

Influence of multigeneration acclimation to copper on tolerance, energy reserves, and homeostasis of Daphnia magna straus.

A multigeneration acclimation experiment was performed with Daphnia magna exposed to copper to assess possible changes in tolerance and to establish the optimal concentration range (OCEE) of this species. The hypothesis was tested that as the bioavailable background concentration of an essential metal increases (within realistic limits), the natural tolerance (to the metal) of the acclimated/adapted organisms and communities will increase. During 18 months the daphnids were exposed to six different, environmentally relevant, copper background concentrations ranging between 0.5 and 100 microg Cu L(-1) (7 x 10(-15) and 3.7 x 10(-9) M Cu2+). An increase in acute (effect concentration resulting in 50% immobility: 48-h EC50) and chronic copper (effect concentration resulting in 50% or 10% reproduction reduction: 21-d EC50, 21-d EC10) tolerance was observed with increasing exposure concentration. The 48-h EC50 increased significantly from 204 +/- 24 microg Cu L(-1) to 320 +/- 43 microg Cu L(-1). A nonsignificant change from 48.0 (47.9-48.0) microg Cu L(-1) to 78.8 (66.3-93.6) microg Cu L(-1) was noted in the chronic toxicity assays. The optimal concentration range was assessed using different biological parameters (i.e., net reproduction [R0]), energy reserves (Ea), body length measurements, filtration rates, and body burdens. After three generations of acclimation the OCEE ranged between 1 and 35 microg Cu L(-1) (2 X 10(-14) to 80 x 10(-12) M Cu2+). Body burden measurements revealed an active copper regulation up to 35 microg Cu L(-1) (80 pM Cu2+). It can be concluded that acclimation of D. magna to copper does occur in laboratory experiments, even at realistic copper background concentrations (10(-11) - 10(-9) M Cu2+). However, it is suggested that this phenomenon is of less importance in the context of regulatory risk assessments. An optimal copper concentration range for D. magna was observed between 1 and 35 microg Cu L(-1) (10(-14) - 10(-11) M Cu2+), indicating that copper deficiency can occur in routine laboratory cultures.

Adaptation, Physiological↗

PubMed1990

Clinical significance of bite force reproduction ability.

The objective of this study was to evaluate the clinical relevance of measurement of bite force reproduction ability. This parameter was measured at reference force levels of 2, 10, and 50 N in a group of patients with articular and nonarticular temporomandibular disorders and in a control group. The ability to reproduce the reference forces was measured at four equidistant occasions. All subjects poorly and imprecisely reproduced the reference force levels. A trend in the matches or in their imprecision could not be found (P greater than 0.05). Bite force reproduction ability did not differ between the patient group and the control group (P greater than 0.05). It was concluded that measurement of bite force reproduction ability does not provide a useful clinical assessment tool.

Adult↗

PubMed1990

Productivity of crossbred cattle on smallholder farms in southern Malawi.

A 10-year set of dairy records from a smallholder dairy scheme in the Republic of Malawi was analysed. Environmental and breed effects on the reproductive and productive parameters were evaluated. Age at first calving for 110, 1/2 Friesian and 55, 3/4 Friesian cows were 36.7 and 40.1 months respectively; calving intervals based on 432 and 145 records were 488 and 482 days; total lactation yields on 554 and 227 records were 1,950 and 2,452 kg. Geographical area of operation, parity of cow, year and month of calving and their interactions did not exert a significant influence on reproductive traits but significantly influenced milk production traits. Deficiency in feed supplies was believed to be a possible cause of problems in reproductive performance.

Animals↗

PubMed2006

Methods for the prediction of breeding success in male cynomolgus monkeys (Macaca fascicularis) used for reproductive toxicology studies.

The cynomolgus monkey (Macaca fascicularis) may be the species of choice for nonclinical reproductive toxicology studies because of the comparability of its reproductive processes to man, similarity of pharmacologic response to various test substances, and decreased probability of immunogenic response to biological therapeutic products. For success in conducting these studies, the male and female monkeys used need to be characterized thoroughly. This study focused on the evaluation of 42 male cynomolgus monkeys as potential breeders for reproductive toxicology studies. Parameters evaluated included age, body weight, testicular volume, serum testosterone levels, ejaculate volume, and sperm parameters (count, motility, and morphology). The results showed that physical parameters (age, body weight, testicular volume) were a good starting point for selection of potential breeder males. However, additional endpoints (testosterone; ejaculate volume; sperm count, motility and morphology; mating behavior) were also helpful as part of an overall "weight of evidence" approach to optimize selection of breeder males. In light of the data obtained in this study, 29 of 42 of the males evaluated were used with excellent success as breeder males for reproductive toxicology studies, resulting in an overall pregnancy rate of 36% when mated with sexually mature females. The successful breeder males were at least 6 y old, weighed at least 5 kg, had testicular volumes of at least 25 ml and serum testosterone levels of 1 to 10 ng/ml, and produced ejaculates with large numbers of sperm (median: 502 x 10(6) per ejaculate) of high quality (few morphologic defects and most sperm highly motile).

Age Factors↗

PubMed2006

Ecotoxicological assessment of effluents in the Basque country (Northern Spain) by acute and chronic toxicity tests using Daphnia magna straus.

Acute pass/fail, multi-concentration tests, and 3-brood chronic toxicity tests with Daphnia magna Straus (Cladocera, Crustacea) were used to characterise industrial and municipal effluents from various sources. The effluents that "passed" the pass/fail tests had 48-h EC50 values >100% and reproduction No Observed Effect Concentration (NOECs) > or =100%, except for one effluent that had a reproduction NOEC of 31.6%. The acute multi-concentration toxicity tests allowed a rapid classification of effluents from Very Toxic (48-h EC50 < 25%), to Non-Toxic (48-h EC50 >100%). The acute-to-chronic ratio (ACR: 48-h EC50 divided by the NOEC for reproduction) in the studied effluents ranged from 5 to about 100. From these results, we propose a step-wise protocol for assessing effluent toxicity. First, effluent is evaluated by means of simple and rapid pass/fail acute toxicity tests, to discriminate Non-Toxic from potentially Toxic effluents, thus facilitating the establishment of priority actions. Second, 48-h ECx is estimated to classify effluents on a toxicity scale from Non-Toxic to Very Toxic. Third, chronic multi-concentration tests are used to calculate reproduction NOECs. These parameters combined with data on effluent chemical composition, chemical and hydrological characteristics of receiving waters, and biological quality criteria can be jointly used for more rational regulatory practices and risk assessment of effluents.

Animals↗

PubMed1990

Sialic acid and neuraminidase activity in the frog oviduct: comparative biochemical investigation in the different tracts during the reproductive cycle.

1. A biochemical study was carried out on the protein-bound and lipid-bound sialic acid, and neuraminidase activity in the different tracts of the oviduct of the frog Rana esculenta during the reproductive cycle. 2. Plasma sexual steroids were also investigated by RIA. 3. Fluctuations in neuraminidase activity are related to that of glycoprotein sialic acid and plasma estradiol. Glycolipid sialic acid does not have a close relationship either with neuraminidase or plasma estradiol. 4. Very high plasma concentration of progesterone before ovulation and, on the contrary, its drop after ovulation were observed. 5. The results are discussed and hypotheses advanced to explain fluctuations of the studied parameters during the reproductive cycle.

Animals↗

PubMed1995

Testicular spermatid and epididymal sperm head counts as an indicator for reproductive toxicity in rats.

The testes of rats were exposed to a single soft x-ray irradiation at levels of 10, 25 and 63 Gy. Testicular and cauda epididymal weights and their sperm counts were decreased at 7 weeks after the irradiation. Histologically, there was an evidence of interrupted spermatogenesis dose-dependently. Animal mating trails, in which irradiated males were mated with untreated females revealed a slight increase in early stage of postimplantation loss at as low as 10 Gy. There were increases in preimplantation and early stage of postimplantation losses in the group of irradiated at 25 Gy. Infertility occurred in irradiated males at 63 Gy. The effects of irradiation were more severe on the sperm count parameters than on reproductive organ weights, histological examination and reproductive status. The testicular spermatid and epididymal sperm head counts are considered to be useful indicators to detect quantitatively the adverse effects on spermatogenesis.

Animals↗

PubMed2006

Long-term non-hormonal male contraception in mice using N-butyldeoxynojirimycin.

BACKGROUND: The imino sugar N-butyldeoxynojirimycin (NB-DNJ) causes reversible infertility in male mice. This compound may have promise as a male contraceptive, because it is already in clinical use, for a non-reproductive condition. As contraceptives need to be taken for extended periods of time, it was essential to evaluate NB-DNJ for its reproductive effects over a long period of administration. METHODS: We have assessed the imino sugar for its long-term effects on the fertility of male C57BL/6 mice, reversibility and potential cumulative toxicity by monitoring various reproductive and systemic parameters over 12 months. RESULTS: Long-term low-dose (15 mg/kg/day) administration of NB-DNJ was sufficient to maintain infertility in male mice. In contrast to short-term drug treatment, imino sugar exposure for more than 3 months resulted in reduced sperm counts. Male mice that had been administered imino sugar for 6, 10 or 12 months and were then maintained without drug administration regained their fertility within 9 weeks after withdrawal of the drug. Prolonged NB-DNJ intake did not affect reproductive hormone levels, serum biochemistry or animal behaviour. CONCLUSION: Low-dose treatment with NB-DNJ over a long period is an effective approach for the regulation of fertility in a male mammal by non-hormonal means, without causing overt adverse effects.

1-Deoxynojirimycin↗

PubMed1990

[Experimental research on the effect of bioshik (tinidazole) on reproduction indices].

Studies were carried out on the influence of bioshik (tinidazol), synthesised and produced by NPSK of Pharmacy at the Medical Academy on reproduction of male and female rats. The experiments were undertaken after oral administration of bioshik in two doses of 100 mg and 300 mg/kg of body mass (1/20 and 1/10 of LD50) at several stages: I stage during natal application, respectively: 1. during sexual maturation and 2. during the period of sexual maturity and II stage during prenatal administration of bioshik. The studies of the second stage were performed on 3-months old male and female rats, a generation of animals, treated with bioshik during pregnancy. The following parameters were determined: sexual receptivity, reproduction, percentage of early resorptions and mean number of normally implanted fetuses. The described data showed that there was inhibition of sexual receptivity as well as of reproduction after usage of higher doses of 300 mg/kg of body mass only natally and more manifested after application during sexual maturation. There were no data on impairement of the examined parameters for reproduction in offsprings after treatment of pregnant rats with bioshik.

Administration, Oral↗

PubMed2005

Influence of diet on life table parameters of Iphiseius degenerans (Acari: Phytoseiidae).

Abstract. Studies on the reproduction, longevity and life table parameters of Iphiseius degenerans (Berlese) were carried out under laboratory conditions of 25 +/- 1 degree C, 75 +/- 5% RH and 16L:8D h. As food sources for the predatory mite, Ricinus communis L. pollen, all stages of the spider mite Tetrranchus urticae Koch, Frankliniella occidentalis (Pergande) larvae, and Ephestia kuehniella Zeller eggs were selected. All diets were accepted as food by the adult mites. Female longevity ranged from 29.5 to 42.4 days, the highest value was recorded on a diet of Ephestia eggs. The highest percentage of females escaping the experimental arena was observed on the diet consisting of thrips larvae. The highest oviposition rate (1.9 eggs/female.day) was recorded when the predator was fed on spider mites on an artificial substrate. For other diets, oviposition rates ranged from 1.0 to 1.3 eggs/female.day. The intrinsic rate of natural increase (r(m)) of I. degenerans varied between 0.015 and 0.142 females/female x day. The diet consisting of castor bean pollen resulted in the highest population growth whereas the diet on spider mites brushed off onto a bean leaf arena resulted in the slowest population growth. This can be explained by the inability of the predator to cope with the webbing of T. urticae, and the high escape rate of the progeny when reared on spider mites. The percentage of females in the offspring ranged from 40 to 73%.

Animals↗

PubMed2004

Physiological interactions of silver and humic substances in Daphnia magna: effects on reproduction and silver accumulation following an acute silver challenge.

Silver (Ag) in aquatic environments mediates its toxic actions by inhibiting sodium influx. Humic substances protect against silver toxicity by complexing the toxic, ionic form of the metal, but may also directly stimulate sodium influx in aquatic organisms. This study investigated the effects of silver and humic substances on the water flea Daphnia magna. Acute silver challenge (24 h; 1 microg L(-1)) and the chronic exposure to humic substances (Aldrich humic acid; 7 mg C L(-1)) had considerable influence on daphnid physiology and reproduction. In particular silver exposure in the absence of humic substances stimulated reproduction, resulted in enhanced adult mass, and altered both the response of the animal to subsequent silver exposure and a physiological surrogate measure of silver toxicity (whole body sodium concentration). The presence of humic substances countered the effects on adult mass and reproduction, returning these parameters to control levels. Humic substances also lowered silver body burden, but with significantly improved whole body sodium status than previously silver-exposed animals. These changes may distort the correlation between silver body burden and indicators of toxic action, an important tenet of site-specific risk assessment tools such as the biotic ligand model.

Animals↗

PubMed1998

Effects on pubertal growth and reproduction in rats exposed to lead perinatally or continuously throughout development.

The reproductive, endocrine, and growth effects of developmental lead exposure were assessed using a rat model in which 0.6% lead acetate (w/v) was administered in the drinking water ad libitum during different developmental periods to determine if lead actions were a result of direct effects of continuous exposure to the metal ion or secondary to disrupted neonatal "endocrine imprinting." Sprague Dawley rats were exposed to lead: (1) from gestational d 5 through birth; (2) during pregnancy and lactation; (3) during lactation only; (4) from birth through adulthood; or (5) from gestational d 5 through adulthood. Lead effects were measured on the development of aspects of the reproductive system, adult sex steroid levels, and growth rates in both male and female animals. The relative weights of male secondary sex organs in adult offspring were not significantly affected in any of the lead-treated groups. In contrast, female pups exposed to lead from birth through adulthood or from gestational day 5 through adulthood were observed to have significantly delayed vaginal opening and disrupted estrus cycling. These effects on female reproductive physiology were not observed in animals where lead exposure was confined only to pregnancy or lactation. Significant suppression of adult mean serum testosterone levels was only observed in male pups exposed to lead continuously from gestational age 5 d throughout life. Lead decreased birth weight in all animals exposed in utero and mean body weights were significantly decreased in all lead-treated groups up to weaning. Analysis of growth curves revealed that all lead-treated groups had significantly reduced growth rates during lactation. However, in addition, in male pups exposed to lead during pregnancy and lactation, from birth or from gestational age 5 d, growth rates were also significantly reduced during puberty. Postpubertal growth rates were unaffected in any lead-treated group. Thus, delayed female reproductive development and suppression of adult male serum testosterone concentration required continuous exposure to the heavy metal. Little evidence was observed for an alteration of "endocrine imprinting" by lead on either reproductive or growth parameters. Exposure during early development (pregnancy and lactation) resulted in no permanent effects in this model other than small (10%) decreases in the body weight of pups postpuberty.

Administration, Oral↗