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PubMed2006

A potential use of color ultrasound as a tool for reproductive management: New observations using color ultrasound scanning that were not possible with imaging only in black and white.

Ultrasonography (US) has been applied to the ovary and the uterus of domestic animals from the late 1980s, and established in 1990s as a practical tool for animal production. US made it possible to detect pregnancy at a very early stage and, most importantly, to observe the real-time dynamics of follicular development and hence the discovery of follicular waves. This has greatly contributed to our understanding of ovarian physiology and helped us to develop several "pin-point" protocols for hormonal treatment. While US may not seem to fit preconceived ideas of a "green" technology, it does not contravene environmental priorities, and it is non-invasive ("ethical") and non-hormonal ("clean"). Using the US technology that is now commercially available at a reasonable price, we are able to estimate the best timing for AI and this allows us to plan either the use of precisely-timed nutritional supplements for fetal development or an immediate 2nd AI service to achieve a better economic efficiency. During the last few years, we have also begun to be able to observe in detail the local blood flow in individual ovarian follicles and CL using color Doppler ultrasonography in the cow. From the series of observations, we have found that: 1) the change of blood supply to an individual follicle closely relates to the dynamics of follicular growth and atresia; 2) the local blood flow detected in the theca externa of mature follicles rapidly increases around the onset of LH surge and is most active before ovulation; 3) the blood supply to the developing CL increases in parallel with CL volume and plasma progesterone concentrations; and 4) the local blood flow surrounding the mature CL acutely increases prior to the onset of luteolysis in response to uterine as well as exogenous PGF(2alpha). It is now clear that color Doppler ultrasound is very useful for observing echogenicity with local blood flow thereby providing an easily obtained estimation of the physiological status of follicles, CLs and early conceptus. Widespread commercial application of color US will depend on further technological developments that reduce the cost and improve performance and ease-of-use. Overall, US is now a most effective non-invasive tool for managing reproduction, at the level of both the individual animal and the herd system. In particular, US can help us to clarify potential problems in high-producing dairy cattle during the postpartum period.

Animals↗
PubMed1993

The suprachiasmatic nucleus of the mink (Mustela vison): apparent absence of vasopressin-immunoreactive neurons.

The hypothalamic suprachiasmatic nucleus is centrally involved in generation of several circadian rhythms. Neurons of the mammalian suprachiasmatic nucleus express a number of neuropeptides including vasopressin. The suprachiasmatic nucleus of the mink (Mustela vison) is easily distinguished from neighbouring hypothalamic areas and the underlying optic chiasm as a small nucleus containing densely packed parvocellular neurons. A dorsal and ventral subdivision were clearly recognized within the midportion and caudal part of the nucleus. Using immunohistochemistry, we have identified vasopressin-, neurophysin-, and vasoactive intestinal peptide-immunoreactive neuronal elements in the hypothalamus of the mink. Vasoactive intestinal peptide-immunoreactive neurons can be observed in the ventral aspect of the suprachiasmatic nucleus, but to our surprise, no vasopressin immunoreactive perikarya are found within the suprachiasmatic nucleus, this absence being independent of the experienced annual cycle. The hypothalamic paraventricular and supraoptic nuclei contain large numbers of vasopressin-, neurophysin- and vasoactive intestinal peptide-immunoreactive magnocellular neurons with extensive projections towards the infundibulum and neurohypophysis. A comparative analysis of the distribution of vasopressin-immunoreactive elements in a number of conventional laboratory animals has demonstrated that, in contrast to the rat, golden hamster and Mongolian gerbil, neither vasopressin-containing perikarya in the suprachiasmatic nucleus nor fine calibered immunoreactive fibres entering the adjacent subparaventricular zone are present in the mink. The mink is a photodependent seasonal breeder, and thus vasopressin-immunoreactive neurons in the suprachiasmatic nuclei may not be essential for the photoperiodic regulation of reproduction and seasonal events experienced by this species.

Animals↗
PubMed2006

Cancer risk among Danish women with cosmetic breast implants.

The available epidemiologic evidence does not support a carcinogenic effect of silicone breast implants on breast or other cancers. Data on cancer risk other than breast cancer are limited and few studies have assessed cancer risk beyond 10-15 years after breast implantation. We extended follow-up of our earlier cohort study of Danish women with cosmetic breast implants by 7 years, yielding 30 years of follow-up for women with longest implant duration. The study population consisted of women who underwent cosmetic breast implant surgery at private clinics of plastic surgery (n = 1,653) or public hospitals (n = 1,110), and a control group of women who attended private clinics for other plastic surgery (n = 1,736), between 1973-95. Cancer incidence through 2002 was ascertained using the Danish Cancer Registry. Risk evaluation was based on computation of standardized incidence ratios (SIR) and Cox proportional hazards models, adjusting for age, calendar period and reproductive history. We observed 163 cancers among women with breast implants compared to 136.7 expected based on general population rates (SIR = 1.2; 95% confidence interval [CI] = 1.0-1.4), during a mean follow-up period of 14.4 years (range = 0-30 years). Women with breast implants experienced a reduced risk of breast cancer (SIR = 0.7; 95% CI = 0.5-1.0), and an increased risk of non-melanoma skin cancer (SIR = 2.1; 95% CI = 1.5-2.7). Stratification by age at implantation, calendar year at implantation and time since implantation showed no clear trends, however, the statistical precision was limited in these analyses. When excluding non-melanoma skin cancer, the SIR for cancer overall was 1.0 (95% CI = 0.8-1.2). With respect to other site-specific cancers, no significantly increased or decreased SIR were observed. Similar results were found when directly comparing women who had implants at private clinics with women who attended private clinics for other plastic surgery, with rate ratios for cancer overall, breast cancer and non-melanoma skin cancer of 1.1 (95% CI = 0.8-1.6), 0.7 (95% CI = 0.4-1.3) and 1.5 (95% CI = 0.8-2.7), respectively. In conclusion, our study lends further support to the accumulating evidence that silicone breast implants are not carcinogenic. Reasons for the consistently reported deficit of breast cancer among women with breast implants remain unclear, whereas increased exposure to sunlight may explain the excess occurrence of non-melanoma skin cancer. We found no indication of delayed diagnosis of breast cancer due to the presence of breast implants.

Adolescent↗
PubMed2005

Opportunities for detection and use of QTL influencing seasonal reproduction in sheep: a review.

Genetic improvement in traits associated with seasonal breeding in sheep is challenging because these traits have low heritabilities, are generally not expressed until late in life, are commonly recorded only in females, and are expressed only in some lambing seasons and management systems. Detection of quantitative trait loci and their use in marker-assisted selection could therefore substantially enhance selection responses. A population of sheep with an extended breeding season was developed through selection for fertility in spring matings and provides opportunities for further study of candidate genes influencing seasonal breeding. In particular, the melatonin receptor 1a gene is polymorphic in many sheep breeds and appears to influence a number of seasonal reproductive responses. In addition, a variety of clock genes have been identified in laboratory mammals and shown to influence biological rhythms. Mutations in these clock genes have been identified and shown to influence circadian periodicities and reproductive patterns in golden hamster and mouse. In sheep, expression of clock genes in the suprachaismatic nucleus and pars tuberalis (PT) suggests that "calendar" cells in the ovine PT play a role in maintaining circannual rhythms. Thus the various clock genes represent potentially important candidate genes that may be involved in control of seasonal breeding.

Animals↗
PubMed1985

Circadian rhythms and photoperiodism.

The circadian timing system plays a critical role in the regulation of seasonal modifications in reproductive function. By detecting and transducing changes in the day-length (photoperiod), the neural substrates of the circadian system, including the supra-chiasmatic nuclei of the hypothalamus, trigger reproductive activity or quiescence at the appropriate seasons of the year in photoperiodic species. The circadian system also plays a role in the expression of endocrine changes that occur with seasonal breeding. Surges in luteinizing hormone secretion in female hamsters, for example, are either expressed daily during reproductive quiescence or suppressed on three out of the four days of the cycle during the breeding season. By such mechanisms a daily timer can be used in the regulation of cyclic events of much longer period.

Animals↗
PubMed1993

The photorefractoriness in domestic goose: effect of gonads and thyroid on the development of postbreeding prolactinemia.

Blood samples were taken from adult male and female geese, and from gonadectomized (GX), thyroidectomized (TX) and gonadectomized+thyroidectomized (GX+TX) ones during the reproduction peak period (March 16), at the beginning of photorefractoriness (June 14), in the second half of the photorefractory period (August 14), and at the beginning of the postrefractory period (October 2). Surgeries were carried out at the age of 10-13 weeks. The birds were kept under natural light conditions. From the blood plasma prolactin (PRL), luteinizing hormone (LH), testosterone (T), progesterone (P4), 17 beta-oestradiol (E2) as well as thyroxine (T4) and triiodo-tironine (T3) were determined by RIA methods. At the beginning of photorefractoriness in intact geese the LH and E2 levels significantly decrease, relative to sexually active period, whereas the P4 remains at a high level. In ganders the LH shows only a slight decrease but the T level is significantly lower than in spring. The PRL, T4 and T3 levels increase after reproduction and give a peak value in both sexes. In both GX ganders and geese decreased T, P4 and T3 levels are observable and the PRL is decreased in females, and the LH is increased in both sexes. Gonadectomy does not influence the E2 in females, the PRL in males and the T4 in both sexes. In TX birds the PRL is higher in March and lower in June than the control level, but these changes are significant only in females. In TX females the P4 level is lower during reproduction and at the beginning of photorefractoriness. The T and E2 levels do not change during the photorefractoriness. In the second half of photorefractoriness a low PRL and P4 level, an increasing LH, T and medium high T4 and T3 levels characterized the intact male and female geese. In GX animals an increase of LH levels is occurred in both sexes. The T4 is higher in castrated-, and lower in ovarectomized geese. In TX birds the P4 is higher than in controls, but the difference is significant only in males. The levels of PRL, LH, T and E2 remain unchanged in TX animals. At the beginning of the postrefractory phase the T (in males) and the P4 and the T4 level increase in both sexes. The PRL and LH show a low value. In GX animals the high LH level refer to the increased sensitivity of hypothalamo-gonadotropic system, because of the absence of negative feed-back of sexual steroids.4+ in both sexes and a high thyroid hormone level and a transitional slight reactivation of gonadotropic-gonadal system occur then.

Analysis of Variance↗
PubMed2002

Relationship between time period after vasectomy and the reproductive capacity of sperm obtained by epididymal aspiration.

BACKGROUND: It is not well defined whether the elapsed time after vasectomy has any influence on the outcome of IVF-ICSI using epididymal sperm. We analysed retrospectively the results of 151 ICSI cycles in which sperm of vasectomized men were used at different time periods after vasectomy. METHODS: Oocytes were obtained after a desensitizing ovarian stimulation protocol using GnRH agonist in association with recombinant FSH and HCG. Sperm were retrieved by percutaneous epididymal sperm aspiration. The cycles were split into three groups: < or =10 years after vasectomy (group 1, n = 47), 11-19 years after vasectomy (group 2, n = 79), and > or =20 years after vasectomy (group 3, n = 25). RESULTS: As might be expected, the mean age of men differed in the three groups (group 3 > group 2 > group 1), and the mean age of the women was also significantly higher in group 3 than in groups 1 and 2, although no differences were described between groups 2 and 3. All other laboratory and clinical parameters were similar in the three groups. Ongoing pregnancy and implantation rates (34, 25, 8% and 22, 15, 6% respectively) decreased significantly from group 1 to group 3. CONCLUSION: Pregnancy and implantation rates after ICSI with sperm from vasectomized men are negatively correlated with the time interval from vasectomy, which cannot be explained purely by male or female ageing.

Adult↗
PubMed2005

Seasonal changes in daily torpor patterns of free-ranging female and male Daubenton's bats (Myotis daubentonii).

Daily torpor can provide significant energy and water savings in bats during cold ambient temperatures and food scarcity. However, it may reduce rates of foetal and juvenile development. Therefore, reproductive females should optimize development by minimizing times in torpor. To test this hypothesis, the use of torpor by female and male free-ranging Daubenton's bats (Myotis daubentonii) during reproduction (gestation, lactation, and post-lactation period) was investigated in 1998 and 1999. Temperature-sensitive radio transmitters were attached to the bats to measure skin temperature. Simultaneously, ambient temperature was recorded. While both sexes became torpid during daytime, male bats used daily torpor (>6 degrees C below individual active temperature) significantly more often during reproductive period (mean: 78.4 % of day time in May and 43 % in June) than females. Female bats went into daily torpor, particularly in late summer when juveniles were weaned (mean: 66.6 % of daytime). Lowest skin temperatures occurred in a female bat with 21.0 degrees C during post-lactation. Skin temperatures of male bats fluctuated from 16.8 degrees C in torpor to 37.2 degrees C during times of activity. There was a significant effect of reproductive period on skin temperature in females whereas mean ambient temperature had no significant effect. However, mean ambient temperature affected mean skin temperatures in males. Our findings indicate that female Daubenton's bats adopt their thermoregulatory behaviour in particular to optimize the juvenile development.

Animals↗
PubMed1979

Circannual changes in plasma concentrations of immunoreactive retinol-binding protein and luteinizing hormone in male and female Japanese quail.

In a single experiment, lasting for 18 months, male and female quail were exposed to an annual cycle of artificial photoperiod synchronized with sunrise and sunset, and their plasma levels of immunoreactive retinol-binding protein (IRBP) and LH were monitored at frequent intervals. Plasma levels of both IRBP and LH showed a repeating annual cycle with maximal levels during the spring/summer, the period of reproductive activity and highest rate of egg-laying, and minimal levels during the autumn/winter. Plasma levels of IRBP and LH were significantly, but only weakly, correlated with each other. The possible role of LH in the regulation of plasma IRBP during reproduction is discussed. Evidence is presented that the proportion of IRBP which does not carry retinol (retinol-binding apoprotein; apoRBP) varies throughout the female breeding cycle and that the high apoRBP concentration noted in the spring/summer period may be related to the deposition of retinol in the egg.

Animals↗
PubMed2006

The relationship between obesity and health related quality of life of women in a Turkish city with a high prevalence of obesity.

The purpose of this study was to demonstrate the relationship between body weight and HRQOL in a representative sample of nonpregnant women in reproductive age period. The data of this cross-sectional study was extracted from a survey: Manisa Demographic and Health Survey (MDHS) conducted in Manisa city in 2000. The study population of MDHS is a representative sample of 1602 reproductive (15-49) age women. World Health Organization Quality of Life Questionnaire abbreviated version (WHOQOL-BREF), which was composed of four domain factors (physical, psychological, social relations and the environment), was used to assess HRQOL. Each of four domains had a possible score ranged between 0 (poor HRQOL) and 20 (excellent HRQOL). The mean age of the women was 35.29+/- 8.19 years. Among them, 35.8 % had normal weight (BMI 18.5 to 24.9), 32.3 % were overweight (BMI 25.0 to 29.9) while 31.9 % were moderate and 3.4% were morbidly obese. After adjusting for age, level of education and co-morbid illnesses, subjects with a BMI higher than normal value, had significantly lower HRQOL scores, compared to normal-weight individuals on each of the domains, except for the environmental domain. Our results suggested that the body weight alone could negatively affect HRQOL. In other words, obesity not only increased the risk of morbidity and mortality, but also affected the perceived health and life quality negatively. In conclusion, in addition to age, socioeconomic status and co-morbid illnesses, body weight should also be controlled in studies examining HRQOL.

Adolescent↗
PubMed1987

Effects of the light-dark cycle and scheduled feeding on behavioral and reproductive rhythms of the cyprinodont fish, Medaka, Oryzias latipes.

Medaka were maintained on a 16:8 light-dark cycle and fed once daily on one of 5 different feeding schedules. The daily rhythm of agonistic behavior rapidly entrained to the scheduled feeding time and maintained this entrainment during a 3-day starvation period. In contrast the daily rhythms of egg laying and courtship stayed entrained to the L:D cycle regardless of the feeding schedule. Thus, temporal integration of this fish with its daily environment can involve multistimuli which concurrently and differentially entrain externally expressed circadian systems.

Agonistic Behavior↗
PubMed1995

Seasonal fiber growth cycles of ferrets (Mustela putorius furo) and long-term effects of melatonin treatment.

Pelage cycles of ferrets are poorly documented, although it is clear that their timing is sensitive to daylength, mediated by pineal melatonin. Hair follicles were monitored histologically in ferrets from 3 to 19 months of age in order to describe naturally occurring changes in follicle growth status and follicle number over three successive cycles of fur growth. Melatonin was administered to some of these animals in late summer to determine the long-term effects of perturbation of hormonal control. Circulating melatonin was elevated for approximately 50 days by 8-mg continuous release implants. Treated animals grew both their first winter coat, and subsequent summer coats 18 days in advance of untreated controls, but this effect did not extend to the second winter coat. Reimplantation the following year induced an advancement of the autumn follicle growth as in the 1st year. Autumn fiber growth occurred at similar times in untreated males and females, and response to melatonin did not differ between sexes. Hair follicle regression and shedding during the natural spring molt was also contemporaneous in males and females, but fiber regrowth occurred 4-6 weeks later in males as compared with females, suggesting that reproduction-related factors affect fiber growth initiation, and that fiber growth and shedding are physiologically distinct processes. Melatonin implants in autumn also affected reproduction in the spring, advancing oestrus by 3-4 weeks. These results show that interference with photoperiodic and hormonal control mechanisms in ferrets can affect pelage and reproductive cycles for up to 10 months.

Animals↗
PubMedDate not supplied

[Aspartate kinase complex of Anabaena variabilis during the early period of development of cyanophage A-1].

Aspartate kinase activity in cells of A. variabilis has been studied in the dynamics of development of virus infection. An early period of reproduction of cyanophage A-1 has been determined to be conjugated with the increase of biosynthesis of amino acids from aspartate family. Five isoenzymes of aspartate kinase were isolated and purified from A. variabilis cells during early development period of cyanophage A-1. Physicochemical properties and influence of amino acids of aspartate family on the activity of homogeneous isoenzymes have been studied. Retroinhibition effect was not observed in infected cyanobacteria cells, which probably enables one to increase 2-7 times the concentration of amino acids in a cell. Such an increase of the amino acids pool is apparently necessary for realization of viral genome strategy.

Aspartate Kinase↗
PubMed2006

Annual cycles of solar insolation predict spawning times of Caribbean corals.

Seasonal increases in sea surface temperature (SST) have long been considered the trigger for mass spawning events in reef corals. We critically examined the relationship between SST and the spawning activity of broadcasting corals in the tropical western Atlantic (Caribbean). This meta-analysis examined 12 species of broadcasting corals at 25 sites spanning 22 degrees of latitude (10 degrees-32 degrees N) from Venezuela to Bermuda in the Atlantic Ocean from 1986 to 2004. Sigmoidal logit regression models were used to examine the relationship between the release of reef-coral gametes and the environmental variables SST and solar insolation defined as (1) the cumulative response 7-10 months prior to spawning (integral); (2) the rate of change at the time of spawning (derivative); and (3) the average for the month of spawning. The Quasi-Newton method was used to estimate the maximum likelihood of the response function. We demonstrate that the recent history and rate of change in temperature correlate poorly with the timing of spawning, while the average temperature during the month of spawning was significant (with all corals releasing gametes 28-30 degrees C, except Montastraea annularis, which released gametes at 27-30 degrees C). In contrast, the rate of change and the cumulative response of solar insolation cycles was a better predictor of gamete release, but solar insolation intensity at the time of spawning was not. These models have important implications for predicting coral reproductive cycles in all oceans, and for examining other marine phototrophic systems beyond corals.

Animals↗