Effects of 2-ethylhexanoic acid on reproduction and postnatal development in Wistar rats

Reproductive toxicity of 2-ethylhexanoic acid (2-EHA) was studied in Wistar rats. The animals (24 animals per sex per group) were given 2-EHA as a sodium salt in drinking water at daily doses of 100, 300, or 600 mg/kg. Control animals received plain water. Male rats were exposed to 2-EHA for 10 weeks and females for 2 weeks prior to mating, both sexes during the mating period and females during the entire gestation and lactation period. 2-EHA caused a slight but dose-dependent decrease in fertility; time to mating increased at 300 and 600 mg/kg and even total infertility ensued. 2-EHA slightly decreased sperm quality in males. The spermatozoa were significantly less motile at 100 and 600 mg/kg and abnormal sperm occurred more frequently at the two highest dose levels. The average litter size was reduced by 16% in the dose group receiving 600 mg/kg. The birth weights of the pups were unaffected but the body weight gain was transiently slower during lactation at 600 mg/kg. Several pups appeared abnormal (kinky tail, lethargic, slightly paralyzed legs) and the physical development assessed by several landmarks (opening of eyes, eruption of teeth, hair growth) and reflexes (grip reflex, cliff avoidance) was delayed at 300 and 600 mg/kg. In another experiment, a single dose of 600 mg/kg 2-EHA was given to pregnant females by gavage on Gestational Day 4, 5, 6, or 7 and the number of implantations were counted on Gestational Day 10. Administration on Day 6 decreased the number of implantations and caused resorptions.(ABSTRACT TRUNCATED AT 250 WORDS)     

A cross-cultural comparison of behavior disturbance and suicidal behavior among psychiatrically hospitalized adolescents in Israel and the United States

This study examines sexual behavior, serotonin turnover in the central nervous system, and testosterone in free-ranging non-human primates. Study subjects were 33 young adult male rhesus macaques (Macaca mulatta) living in naturalistic social groups on a 475-acre South Carolina barrier island. Blood and cerebrospinal fluid (CSF) samples were obtained during random trappings, and the subjects were located for observation by radio telemetry. Quantitative behavioral samples totaling 203 observation hours were taken during two mating seasons (September through January) in 1994 and 1995. Control observations (65 h) on 13 subjects were also taken during the non-mating seasons in 1994 and 1995. The results indicate that CSF 5-hydroxyindoleacetic acid (5-HIAA), CSF testosterone, and plasma testosterone concentrations increase significantly during the mating season. During the mating season, there were significant increases in high intensity aggression, low intensity aggression, grooming behavior, and heterosexual mounting. In the mating season, CSF 5-HIAA was significantly correlated with several sociosexual behaviors: consorts per hour, heterosexual mounts per hour, and inseminations per hour. In contrast to previous findings from the non-mating season, CSF 5-HIAA was not correlated with any measures of aggression or sociality, although during consorting, CSF 5-HIAA was positively correlated with grooming. From these findings, we conclude that the lack of correlation between intense and severe aggression and CSF 5-HIAA in the mating season may reflect the use of high intensity aggression in 'normative' male-male competition over access to reproductively active females. We also conclude that CNS serotonin turnover is positively correlated with sexual competence, i.e. males with low CSF 5-HIAA concentrations are less sexually competent than males with higher concentrations.     

Electroejaculation and semen characteristics of the captive Hokkaido brown bear (Ursus arctos yesoensis)

An electroejaculation technique was applied to the Hokkaido brown bear (Ursus arctos yesoensis) for semen collection and characterization of their seminal traits. Ten captive sexually mature bears were anesthetized and subjected to 21 electroejaculation trials during their mating season in 1995 and 1996. Spermic electroejaculates were recovered from 6 of the 10 bears (14 of 21 trials). The semen was characterized by serous fluid of semitransparent white color and a neutral pH. The mean values of ejaculate volume, sperm concentration, percentage of sperm motility, percentage of live spermatozoa, and percentage of pleiomorphic forms were 2.7 ml, 471.6 x 10(6) cells/ml, 80.2%, 89.7% and 21.8%, respectively. Although there was considerable variation among the seminal traits of the individual bears, the electroejaculation technique was effective in obtaining ejaculates from captive bears.     

Primer on medical decision analysis: Part 2--Building a tree

Observations were made on four captive breeding groups of rhesus monkeys in order to measure hormonal, behavioral, and genital changes in adolescent males during the annual mating season. Three questions were addressed with regard to possible effects of social environment upon reproductive maturation: (1) Does male agonistic rank influence adolescent development? (2) Does affiliation between adolescent males and adult females during the mating season influence the males' reproductive development? (3) Does maternal rank exert any effect upon reproductive maturation in adolescent sons? In many (but not all) cases male rank was positively correlated with circulating testosterone and testes weights during the mating season. Affiliative behavior (allogrooming and sexual interactions) between adolescents and adult females in their social groups bore no relationship to the degree of reproductive maturation in males. Mounts involving intromission were infrequent, but sons of high-ranking mothers gained significantly more intromissions than sons of lower-ranking females. Maternal rank was also found to correlate with circulating testosterone levels, testes weights, growth of the baculum (os penis), and maintenance of body weight in adolescent sons during the mating season. By contrast, levels of beta-endorphin in the cerebrospinal fluid of adolescent males did not correlate with social rank, testosterone levels, or genital development. These findings point to possible effects of maternal rank, as well as intermale agonistic rank, in determining reproductive maturation during adolescence in the male rhesus monkey.     

Work-family conflict, gender, and health-related outcomes: a study of employed parents in two community samples

Female sifaka mate selectively with one or more resident and/or non-resident males during the breeding season. Various adaptive explanations have been advanced to explain why female primates mate with multiple males including that 1) females seek to confuse paternity and thereby forestall male infanticide and/or ensure male infant care or 2) females seek to ensure fertilization. Assessing the power of fertilization insurance to explain mating patterns in females requires information on the temporal relationship between mating and ovarian hormones. The hormonal correlates of reproduction and mating in free-ranging Propithecus verreauxi were investigated using excreted steroids as indices of reproductive state. Solid-phase extraction and radioimmunoassay techniques were used to measure unconjugated estradiol (E(2)) and progesterone (P(4)) in 485 desiccated fecal samples collected from five female sifaka before and during the breeding season at Beza Mahafaly, Madagascar. Results suggest that behavioral estrus was characterized by 10 to 15-day elevations in E(2); hormonal activity was observed to be similar to pseudo-estrus reported for other lemur species; apparent conception was associated with sustained P4 elevations beginning 1 to 3 days post-estrus with gestational phase elevations of E2 beginning 42 to 45 days post-conception; and mating with multiple partners appeared not to be a prerequisite to fertilization, as conception resulted from both monoandrous and polyandrous matings. These preliminary data suggest that fertilization insurance is not adequate to explain polyandrous mating in sifaka at Beza Mahafaly.     

Sexual activity and anomalous spermatogenesis in young male silver foxes

The total number of spermatozoa in ejaculate of males with normal sexual activity was 165,647,5 million and the mean percentage of morphologically abnormal spermatozoa was 21,64,4%. The percentage of morphologically defective spermatozoa in sexually inactive males was significantly lower than in sexually active ones.     

Timing of mating, sperm dynamics, and ovulation in a wild population of agile Antechinus (Marsupialia: dasyuridae)

Timing of mating, sperm transport and storage, and ovulation were examined in a wild population of agile Antechinus (Marsupialia: Dasyuridae) in order to ascertain the validity of direct comparisons between captive and field-based mating studies in this species. Mating commenced in early August, and all females had ovulated by the 27th of the month. Fifty-five percent of the mated females caught that had not yet ovulated were captured on 19-20 August. This corresponded with a peak (67%) in the ovulation date determined for pregnant females. Approximately 25.9 x 10(3) spermatozoa per side were recovered from the reproductive tract of each mated female captured (range: 1.7 x 10(3)-75.5 x 10(3) spermatozoa per side). Spermatozoa were consistently found in greater numbers in the lower isthmus (19.7 x 10(3) +/- 19.9 x 10(3) spermatozoa per side) of the oviduct ( approximately 67% of all sperm found in the female tract; range 17-94%) than elsewhere in the reproductive tract. Few spermatozoa were found in the upper isthmus, and none were detected in the ampulla. Sperm number in the female reproductive tract supports the hypothesis that females will mate several times within the one estrus. At the conclusion of the rut, approximately 80.0 x 10(3) spermatozoa remained in each testis and approximately 630 x 10(3) spermatozoa in each epididymis. Most epididymal spermatozoa were restricted to the distal corpus/proximal cauda regions of the duct. This study shows that both field and laboratory reproductive data correlate well in the agile Antechinus and that successful breeding is indeed an exercise in reproductive brinkmanship.     

Trends and international comparisons in infertility in circumpolar areas

A study was carried out at the International Livestock Research Institute (ILRI) Debre Berhan Research Station in Ethiopia from 1992 to 1995 to compare the peri-parturient rise (PPR) in faecal nematode egg counts (FEC) in ewes of two indigenous sheep breeds. A total of 1439 Menz and 1347 Horro ewes were single sire mated following oestrus synchronization to lamb in the wet and dry season. Three ewe treatment groups were constituted as mated/lactating/undrenched; mated/lactating/drenched; unmated/undrenched for three wet and three dry lambing seasons. All ewes grazed naturally contaminated pasture. Levels of faecal egg output were monitored at mating, 3 months after mating, 2 weeks before lambing, 4, 8 and 12 weeks post-lambing. A significant PPR in FEC occurred 2 weeks before lambing and peaked at 4 weeks post-parturition in ewes lambing just before the beginning of the dry season (October/November). There was no significant increase in FEC when lambing occurred before the onset of the long rainy season (May/June). The PPR in this study was associated with both lactation and seasonal availability of third-stage infective larvae on pasture. There was no consistent breed difference in FEC during the six sampling periods from mating to weaning. Faecal cultures and worm counts from both breeds confirmed the presence of Longistrongylus (Pseudomarshallagia) elongata, Trichostrongylus spp.and Haemonchus contortus. The role of the peri-parturient rise of FEC in ewes in gastrointestinal nematode transmission is discussed.     

Association of sex of fetus, sire, month of conception, or year of foaling with duration of gestation in standardbred mares

OBJECTIVE: To determine whether sex of fetus, sire, month of conception, or year of foaling was associated with duration of gestation in mares. DESIGN: Epidemiologic retrospective cohort study. ANIMALS: 500 foalings for 296 Standardbred mares. PROCEDURE: Data for reproductive events from 1986 to 1992 were analyzed. Analyses were conducted to determine whether duration of gestation was associated with sex of fetus, sire, month of conception, or year of foaling. RESULTS: Mean duration of gestation was 343.3 days and was significantly greater for colt fetuses (344.4 days) than for filly fetuses (342.2 days). Sire was associated with duration of gestation; gestation after mating with certain sires was consistently less than 340 days in duration, whereas duration after mating with other sires was consistently more than 350 days. Duration of gestation was associated with month of conception, decreasing by about 2.5 d/mo for mares conceiving later during the breeding season. CLINICAL IMPLICATIONS: Duration of gestation is affected by mating to specific sires and by month of conception. Stallions associated with exceptionally prolonged gestations might be used to breed mares early in the breeding season, whereas stallions associated with shorter gestations might be desirable for mares bred later in the breeding season. Preparations for impending parturition should be more effective and efficient with improved information on expected date of parturition.     

Variations in blood testosterone levels of prepubertal foxes and during the seasonal genital cycle of the adult male fox (Vupes vulpes) in captivity

Plasma testosterone levels have been determined by radioimmunoassay on peripheral venous blood samples of young and adult foxes at different times of their genital activity. In the cub, the testosterone levels increase from November to January; at this time, the young is pubescent. In the adult, the testosterone levels are low from April to November. At this time, the levels increase and reach a maximum value from December to February, which is the mating season. Some high testosterone levels observed in summer prove that the endocrine activity of the testis persists during the out-breeding season.     

Induction of specific-locus and dominant lethal mutations in male mice by trophosphamide

Trophosphamide induced dominant lethal and specific-locus mutations in spermatozoa and spermatids of mice. The induction pattern of specific-locus and dominant lethal mutations shows two maxima in the mating intervals 1-4 and 9-16 days post treatment. The nature of induced mutations is suggested to be intergenic.     

Hoechst staining and exposure to UV laser during flow cytometric sorting does not affect the frequency of detected endogenous DNA nicks in abnormal and normal human spermatozoa

Controlling the sex of offspring by the separation of X and Y chromosome-bearing spermatozoa using flow cytometry has been reported as a clinical technique aiding prevention of X-linked diseases. Although this technique has resulted in several hundred normal births in animals and at least one human birth, there is still concern over its genetic safety due to the involvement of two potentially mutagenic agents: UV light and the fluorochrome dye, Hoechst 33342 (H33342). Human spermatozoa, particularly those considered abnormal, may be more likely to suffer DNA damage following exposure to mutagenic agents, compared with other mammalian species. The stability of normal fresh and decondensed human spermatozoa were examined after exposure to a range of levels of UV and H33342 staining, using an assay that detects endogenous nicks in the DNA of spermatozoa. The stability of abnormal and normal, fresh and frozen-thawed human spermatozoa was examined following UV laser, H33342 staining and flow cytometry treatments utilizing the same assay. There was an increase in the presence of endogenous nicks when spermatozoa were decondensed compared with fresh spermatozoa. There was no increase in the incidence of nicks in any group of spermatozoa after UV and fluorochrome exposure compared with controls without exposure.     

Male traits, mating tactics and reproductive success in the buff-breasted sandpiper, Tryngites subruficollis

Buff-breasted sandpipers use a variety of mating tactics to acquire mates, including remaining at a single lek for most of the breeding season, attending multiple leks during the season, displaying solitarily or displaying both on leks and solitarily. We found that differences in body size, body condition, fluctuating asymmetry scores, wing coloration, territory location and behaviour (attraction, solicitation and agonistic) did not explain the observed variation in mating tactics used by males. Which males abandoned versus returned to leks was also not related to morphology or behaviour, and there was no tendency for males to join leks that were larger or smaller than the lek they abandoned. These results suggest that male desertion of leks was not dependent on a male's characteristics nor on the size of the lek he was presently attending. Males did join leks with larger males than their previous lek, perhaps to mate with females attracted to these larger 'hotshot' males. Males at both leks and solitary sites successfully mated. Lek tenure did not affect mating success, although lekking males appeared to mate more frequently than solitary males. Courtship disruption and to a lesser extent, female mimicry, were effective at preventing females from mating at leks, and may offer a partial explanation for female mating off leks. Our analysis that combined all males together within a year (regardless of mating tactic) indicated that males that attended leks for longer periods of time and that had fewer wing spots were significantly more likely to mate. Given some evidence that wing spotting declines with age, and that females inspect male underwings during courtship, the latter result suggests that female choice may play some role in determining male success. We suggest that male buff-breasted sandpipers may use alternative mating tactics more readily than males in other 'classic' lek-breeding species because: (1) unpredictable breeding conditions in this species' high arctic breeding range leads to low lek stability, which in turn hinders mate selection mechanisms mediated by male dominance and female choice; and (2) males are not constrained by morphological markings that indicate status or sex. Both characteristics may reduce the reproductive benefits associated with males adopting one mating tactic and result in a sort of scramble competition in which males switch between tactics as local conditions change.Copyright 1998 The Association for the Study of Animal Behaviour     

Classification and quantification of abnormal sperm along the epididymal tract. Comparison between adult and aged hamsters

The types and averages of abnormal sperm were studied in the epididymis of adult and aged golden hamsters. Abnormal spermatozoa represent 14.6-19.6% of the total of spermatozoa in adults, 31.7-42.1% in middled-aged hamsters, and 39.3-50% in advanced-aged hamsters. Twelve abnormal shapes were found, with the lack of an acrosome, the lack of a head, and the coiling of the tail, being the most frequent in the three age groups. An important increase in the number of coiled spermatozoa was found in the corpus and proximal cauda of the epididymis, but a decrease was observed in the distal cauda. Our data suggest that the epididymis produces secondary defects in spermatozoa running from the proximal caput to the middle zone of the duct, but that many of these spermatozoa are eliminated in the distal cauda. Such a result is mainly found in aged animals, in which a higher percentage of abnormal sperm from secondary origin is found with respect to adults.     

Testicular needle biopsy, open biopsy, epididymal aspiration and intracytoplasmic sperm injection in obstructive azoospermia

Testicular or epididymal spermatozoa were obtained for in-vitro fertilization and intracytoplasmic sperm injection (ICSI) in 27 cycles out of 33 (in six men the azoospermia proved to have testicular causes). Testicular needle biopsy carried out in addition to surgical open biopsy proved to be an effective method to obtain spermatozoa for ICSI from patients with obstructive azoospermia. Thus it might be possible to replace scrotal operations by simple needle biopsies. Embryos resulting from ICSI with testicular spermatozoa were used in 19 transfers that resulted in six pregnancies. One pregnancy resulted from six embryo transfers from ICSI after microsurgical-epididymal sperm aspiration (MESA). The normal fertilization rates with testicular (37.3%) and MESA spermatozoa (53.7%) did not differ significantly from each other, but with testicular spermatozoa the rate was significantly lower than that obtained with ejaculated spermatozoa and ICSI (59.7%) in the matched couples. The abnormal fertilization of oocytes with one pronucleus was significantly higher with testicular spermatozoa than with ejaculated spermatozoa in the control couples.     

Status quo in "anesthesiology"? American Society of Anesthesiologists 1997 annual meeting--San Diego, October 18-22, 1997]

Percentage and types of morphological abnormalities found in canine spermatozoa were evaluated by three investigators using three stains (Giemsa-Wright stain [Diff-Quik], eosin Y/nigrosin [Hancock], and eosin B/nigrosin [Society for Theriogenology morphology stain] with conventional light microscopy, compared to phase contrast microscopy on unstained samples. The percentage of spermatozoa with abnormal heads, midpieces, and tails varied by technique and by investigator. Average percentages of morphologically normal spermatozoa were significantly higher in samples stained with Diff-Quik and samples examined by phase contrast microscopy than in samples stained with Hancock or Society for Theriogenology morphology stains. No effect of investigator on the percentage of morphologically normal spermatozoa was assessed. Results suggest that staining or preparation technique may alter the morphology of canine spermatozoa artifactually.     

Spatial associations provide a context for social learning of courtship patterns in brown-headed cowbirds (Molothrus ater).

Young brown-headed cowbirds (Molothrus ater) socially learn the behaviors that facilitate courtship and mating patterns. Data from this study indicate that the context for this social learning may be provided by spatial associations between young and old cowbirds before the breeding season. Data from 2 different cultural generations of birds indicated that young cowbirds were found most often near young and adult models of the same sex and least often near cowbirds of the opposite sex. Furthermore, there was a positive correlation between the number of times young males were found nearest adult males and those young males' subsequent courtship success with females during the breeding season. Young cowbirds may therefore be interacting more with cowbirds of their own sex during the time period when young males are learning their vocalizations and young females may be learning their preferences for male vocalizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of aneuploidy in normal and abnormal germ cells from semen of fertile and infertile men

This study was undertaken with the aim of investigating the cytogenetic constitution of normal as well as abnormal spermatozoa and immature germ cells found in semen of normal men and infertile patients. A specific protocol of double in-situ hybridization for chromosomes 1 and 17 based on colorimetric detection of the hybridization signals (ISH) and brightfield microscopy analysis of cellular morphology was applied. Also the influence of paternal age on sperm aneuploidy was investigated. We found that, at least in the age range analysed (28-54 years) and for semen of good quality (total normal motile counts above 10 x 10(6)) (n = 17), paternal age has no influence on baseline rates of sperm aneuploidy. However, with decreasing semen quality (total normal motile sperm counts below 5 x 10(6)) (n = 6) significantly higher rates of sperm aneuploidy for autosomes 1 and 17 were scored (0.8 versus 1.43%) (P < 0.001). Regardless of the type of semen analysed, a number of morphologically abnormal spermatozoa were found to be hyperhaploid or diploid in a high percentage of cases (20 and 10% respectively). The same was found for immature germ cells (aneuploidy rate of 18%). We conclude that in infertile men with poor quality semen a direct relationship may exist between the impairment of the spermatogenesis process (as reflected by an increased production of morphologically and cytogenetically abnormal germ cells) and rates of baseline aneuploidy occurring in normal spermatozoa. Infertile couples undergoing assisted reproduction treatment need to be counselled about the risk of using spermatozoa which may carry higher rates of non-disjunction for different chromosomes. While sperm hyper- or hypohaploidy for some chromosomes (X,Y) implies counselling couples about the risk of abnormal phenotype in their offspring, most autosomal sperm aneuploidies probably translate only into lower rates of embryo fertilization and survival.     

Sperm storage in females of the smooth newt (Triturus v. vulgaris L.): I. Ultrastructure of the spermathecae during the breeding season

Sperm storage in cloacal spermathecae was studied in females of Triturus v. vulgaris collected early in the breeding season in southern England. Females collected in terrestrial situations, presumably unmated, were mated in the laboratory, and the ultrastructure of the transferred sperm and the spermathecae was observed at various intervals after mating. Sperm from a spermatophore cap lodged in a female's cloacal orifice can migrate into spermathecae within 1 hr after mating. Spherical structures on the axial fibers of some sperm in the cap could indicate immaturity. Disorderly clusters of sperm from the cap are still present in the cloacal chamber 12 hr after mating but are absent 24 hr after mating. During storage, sperm often are in tangled masses in the spermathecal tubules. The sperm are coated with spermathecal secretions, and some sperm nuclei were observed embedded in the spermathecal epithelium. Little evidence for spermiophagy early in the breeding season was found. During oviposition, mazes of sperm occur external to the spermathecal orifices, and sperm may be released in this condition onto eggs as they pass through the cloaca. The tangled clusters in which sperm are found from pick-up to oviposition are hypothesized as an adaptation to reduce the effectiveness of sperm competition from the ejaculates of rival males. Additional studies, using the same protocol and covering the entire cycle of sperm storage, are necessary to enable interspecific comparisons leading to phylogenetic hypotheses.     

Cytogenetics of human spermatozoa: correlations with sperm morphology and age of fertile men

Sperm chromosomes from 15 fertile men were analyzed after fusion of their spermatozoa with zona-free hamster eggs. The total proportion of abnormal metaphases as well as the proportions of aneuploidy and structural aberrations were calculated for every man and examined for linear correlations with [1] sperm morphology and [2] the age of the persons studied. A positive correlation between the cytogenetic parameters and the percentage of abnormal sperm morphology was not evident, suggesting that assessment of sperm morphology cannot be used as an indicator of chromosomal damage in human spermatozoa. In contrast, there was a more distinct positive correlation between the age of donors and the three cytogenetic parameters studied.