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Reproductive Ability (reproductive + ability)

Distribution by Scientific Domains

Life Sciences	60%
Medical Sciences	40%

Selected Abstracts

Differential effects of genotoxic stress on both concurrent body growth and gradual senescence in the adult zebrafish

AGING CELL, Issue 2 2007
Stephanie B. Tsai
Summary Among vertebrates, fish and mammals show intriguing differences in their growth control properties with age. The potential for unlimited or indeterminate growth in a variety of fish species has prompted many questions regarding the senescent phenomena that appear during the aging process in these animals. Using zebrafish as our model system, we have attempted in our current study to examine the growth phenomena in fish in relation to the onset of senescence-associated symptoms, and to evaluate the effects of genotoxic stress on these processes. We observed in the course of these analyses that the zebrafish undergoes continuous growth, irrespective of age, past the point of sexual maturation with gradually decreasing growth rates at later stages. Animal population density, current body size and chronological age also play predominant roles in regulating zebrafish growth and all inversely influence the growth rate. Interestingly, the induction of genotoxic stress by exposure to ionizing radiation (IR) did not adversely affect this body growth ability in zebrafish. However, IR was found to chronically debilitate the regeneration of amputated caudal fins and thereby induce high levels of abnormal fin regeneration in the adult zebrafish. In addition, by resembling and mimicking the natural course of aging, IR treatments likewise enhanced several other symptoms of senescence, such as a decline in reproductive abilities, increased senescence-associated ,-galactosidase activity and a reduction in melatonin secretion. Our current data thus suggest that during the lifespan of zebrafish, the onset of senescence-associated symptoms occurs in parallel with continuous growth throughout mid-adulthood. Moreover, our present findings indicate that genotoxic DNA damage may play a role as a rate-limiting factor during the induction of senescence, but not in the inhibition of continuous, density-dependent growth in adult zebrafish. [source]

Disruption of brain development in male rats exposed prenatally to 5-bromo-2,-deoxyuridine

CONGENITAL ANOMALIES, Issue 4 2001
Makiko Kuwagata
ABSTRACT, Sprague-Dawley rats were treated intraperitoneally with 5-bromo-2,-deoxyuridine (BrdU) at 0,12.5 or 50 mg/kg/day on days 9 through 15 of gestation to evaluate the effects on development of the brain of offspring. Prenatal exposure to BrdU induced abnormal development of the brain; dilatation of the lateral ventricles in male offspring in the postnatal period. The ratio of the length of the longitudinal fissure to that of the cerebral cortex decreased in a dose-dependent manner in the embryonic period and thereafter. In 14-week-old male offspring exposed prenatally to BrdU at 50 mg/kg, the cortex layer of the cerebrum was thinner than that of the controls. Masculine sexual behavior was markedly impaired and the volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA) was decreased in the 50 mg/kg group as compared with the controls. These results demonstrate that prenatal exposure to BrdU affected the development of the brain hi the prenatal and postnatal stages and reduced the volume of SDN-POA after puberty, resulting in a disruption of reproductive ability in male rats. [source]

Selenium and mercury concentrations in California gulls breeding on the Great Salt Lake, Utah, USA

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2009
Michael R. Conover
Abstract We examined selenium (Se) and mercury (Hg) concentrations in adult California gulls (Larus californicus) nesting on the Great Salt Lake, Utah, USA, during 2006 and 2007. During 2006, the mean Se concentration (± standard error) was 18.1 ± 1.5 ,g/g in blood on a dry-weight basis and 8.1 ± 0.4 ,g/g in liver. During 2007, Se concentrations were 15.7 ± 1.5 ,g/g in blood and 8.3 ± 0.4 ,g/g in liver; Hg concentrations were 2.4 ± 0.3 ,g/g in blood and 4.1 ± 0.5 ,g/g in liver. Gulls collected from a freshwater colony located within the watershed of the Great Salt Lake had similar levels of Se in the blood and liver as gulls collected on the Great Salt Lake but lower Hg concentrations. Body mass of adult gulls was not correlated with Se or Hg concentrations in their blood or liver. Selenium concentration in California gull eggs collected during 2006 was 3.0 ± 0.10 ,g/g. Of 72 eggs randomly collected from Great Salt Lake colonies, only one was infertile, and none of the embryos exhibited signs of malposition or deformities. We examined 100 newly hatched California gull chicks from Great Salt Lake colonies for teratogenesis; all chicks appeared normal. Hence, the elevated Se and Hg concentrations in adult gulls nesting on the Great Salt Lake did not appear to impair gulls' health or reproductive ability. [source]

Maternal atopy and the number of offspring: Is there an association?

PEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 6 2003
Wilfried Karmaus
We investigated the association between maternal atopy and the number of offspring. In a population- and pregnancy-based survey (part of the European Studies on Infertility and Subfecundity), we obtained information on the number of offspring, adverse pregnancy outcomes, age at pregnancy, and waiting time to pregnancy. The German portion of these surveys also included information on physician-diagnosis of asthma, atopic eczema, or hay fever. The odds ratio (OR) adjusted for age showed that the number of children was reduced among women with atopy (OR = 0.75, 95% CI: 0.57,0.98 in the pregnancy-based sample; OR = 0.79, 95% CI: 0.63,0.99 in the population-based sample). We did not identify other signs of reduced reproductive ability in atopic women. The results provide support for two assumptions: (i) either a lower number of offspring in atopic mothers combined with an increased risk of atopy in offspring of atopic mothers may explain the protective effect of a higher number of siblings on atopy in offspring; or (ii) successive pregnancies may decrease the atopic response of the mother and thus the risk of developing atopy in subsequent offspring. [source]

Effects of indoor air purification by an air cleaning system (Koala technology) on semen parameters in male factor infertility: results of a pilot study

ANDROLOGIA, Issue 3 2009
R. Paradisi
Summary A number of studies indicated a clear decline in semen quality in the past 30,50 years and there is accumulating evidence that this decline might result from exposure to high levels of air pollution. To examine the impact of environment on male reproductive ability, we undertook for the first time a pilot study on semen quality of infertile men exposed to purification of indoor air. Ten subjects with a history of unexplained male infertility and poor semen quality were exposed for at least 1 year to a cleaning indoor air system (Koala technology). The key feature of this air purifier is the unique innovative multiple filtering system. The treatment of total purification of indoor air showed neither improvements in semen parameters nor variation in reproductive hormones (P = N.S.), but induced an evident increase (P < 0.03 and more) in seminal leucocytic concentrations. Within the limits due to the small sample of subjects recruited, the sole purification of indoor air does not seem enough to improve semen quality, although the increase in leucocytic concentrations could indicate an activation of the role of immunosurveillance in a purified indoor air environment. [source]