Search Results
Results 251 - 300 of 1044
< 1 2 3 4 5 6 7 8 9 10 11 >
Rubolini Diego - - 2007
Maternal hormones in vertebrate eggs can mediate important forms of maternal effects. However, the function of hormone transfer to the eggs is still debated, especially because long-term fitness consequences have been little studied. We investigated the effect of prenatal exposure to physiologically elevated yolk testosterone (T) levels on reproduction of ...
Linde Forsberg Catharina - - 2007
BACKGROUND: Dystocia occurs more commonly in some breeds of dogs than others. The Boxer breed is one of the highrisk breeds for whelping problems. The aim of this study was to document some reproductive parameters and the frequency of dystocia in Boxers. METHODS: Two questionnaires were sent to the breeders ...
Buckley David - - 2007
The way in which novelties that lead to macroevolutionary events originate is a major question in evolutionary biology, and one that can be addressed using the fire salamander (Salamandra salamandra) as a model system. It is exceptional among amphibians in displaying intraspecific diversity of reproductive strategies. In S. salamandra, two ...
Féron Christophe - - 2007
In many rodent species males display paternal behaviour. The primary reported effect of this paternal care is to increase pup survival. In mammal females, pregnancy and lactation are energetically demanding, especially when they are concurrent in post-partum reproduction. To face this energy requirement, females generally lengthen the duration of their ...
Gilbert Jeffrey S - - 2007
Inadequate nutrition compromises fetal development and poses long-term health risks for the offspring, even without decreased birth weight. The present study sought to 1) establish the ontogeny of fetal renal glomerulus number (GN) in sheep and 2) evaluate the effects of 50% global nutrient restriction (NR) during early to midgestation ...
Lisboa Sabrina F S - - 2007
BACKGROUND/AIMS: Fluoxetine (FLX) has been widely prescribed for depression during pregnancy and/or lactation. Since serotonin is a neurotrophic factor, the use of FLX by mothers could disrupt brain development resulting in behavioral alterations in their progeny. This study evaluated the effects of developmental FLX exposure on anxiety, depression, aggressivity and ...
Covert S F - - 2007
We investigated the sexual reproductive mode of the two most important etiological agents of soybean sudden death syndrome, Fusarium tucumaniae and Fusarium virguliforme. F. tucumaniae sexual crosses often were highly fertile, making it possible to assign mating type and assess female fertility in 24 South American isolates. These crosses produced ...
Mukhopadhyay Arnab - - 2007
What is the relationship between reproduction and longevity? Evolutionary biology suggests that reproduction exacts a cost in somatic maintenance, a cost that reduces longevity. The frequent occurrence of this tradeoff between life span and fecundity, both due to experimental manipulations as well as natural variation, suggest that the mechanism might ...
Hayes UnJa L UL Department of Psychology and Center for Neuroendocrine Studies, University of Massachusetts, Tobin Hall, Amherst, MA 01003, USA. - - 2007
In prairie voles (Microtus ochrogaster), most virgin females are infanticidal. To determine the onset of maternal responsiveness, female prairie voles were tested for maternal behavior as virgins and at different times throughout pregnancy. Female voles that were infanticidal as virgins by and large remained infanticidal throughout pregnancy. In contrast, about ...
Xu Da-De - - 2007
We studied sexual dimorphism, female reproduction and egg incubation of the oriental leaf-toed gecko (Hemidactylus bowringii) from a population in southern China. The largest male and female in our sample were 60 and 57 mm snout-vent length (SVL), respectively. Males are the larger sex; sexual dimorphism in head size and ...
Miller Kimran E - - 2006
Callitrichid females are often described as energetically constrained. We examined the energy budgets of 10 female wild golden lion tamarins (GLTs, Leontopithecus rosalia) in an effort to understand how energy intake and expenditure might influence physical condition and therefore reproductive performance. We used focal animal sampling to record behavioral data ...
Costantini Ruth M - - 2007
Reproductive behavior of virtually all adult male rodents is dependent on concurrent availability of gonadal steroids. The ejaculatory reflex is incompatible with long-term absence of testicular steroids and typically disappears within 3 weeks after castration. Male Siberian hamsters are an exception to this rule; mating culminating in the ejaculatory reflex ...
Suraweera N - - 2006
Min mice provide a good model of human familial adenomatous polyposis. Recently, we have reported on two recombinant inbred lines (I and V) and the location of a modifier (Mom3) close to Apc, which altered polyp numbers in our mice possibly by modifying the frequency of wild-type (WT) allele loss ...
Stark Michael J - - 2006
OBJECTIVE: Peripheral microvascular function is altered in preeclampsia (PE). Recent studies suggest that maternal physiology varies with fetal sex. We wanted to examine if there were sex-specific differences in maternal peripheral microvascular function in normal pregnancy and pregnancy complicated by PE. METHODS: Peripheral microvascular responses were examined using the noninvasive ...
van Dunné F M - - 2006
Interleukin-10 (IL10) is assumed beneficial for a successful pregnancy; it may increase fertility and fecundity. Allele frequencies of IL10 polymorphisms at position -2849, -1082 and -592 were analyzed in association with a past history of fertility and fecundity in men and women of at least 85 years old. Fertility was ...
Gidlöf Sebastian - - 2007
CONTEXT: The mechanisms behind onset of labor and prolongation of pregnancy are not fully understood, but steroid hormones are thought to contribute. 17-Hydroxyprogesterone has been shown to prolong pregnancy in humans. Male fetuses have been reported to have longer gestation than females. OBJECTIVE: The objective of the study was to ...
Browne P - - 2006
Female spotted hyenas (Crocuta crocuta) have an erectile peniform clitoris and a pseudoscrotum but no external vagina, all established by day 35 of a 110-day gestation. Recent studies indicate that these events are androgen-independent, although androgen secretion by fetal ovaries and testis was hypothesized previously to induce phallic development in ...
Glickman Stephen E - - 2006
Female spotted hyenas (Crocuta crocuta) are the only female mammals that lack an external vaginal opening. Mating and birth take place through a urogenital canal that exits at the tip of a hypertrophied clitoris. This 'masculine' phenotype spurred a search for an alternate source of fetal androgens. Although androstenedione from ...
Young Andrew J - - 2006
In cooperative animal societies, dominant females typically show higher breeding success than subordinates, and are commonly believed to control the extent of reproductive sharing. However, studies of social insect societies reveal that subordinates too can interfere with the breeding attempts of others, with important implications for the distribution of fitness ...
Cammack K M - - 2006
The damaging effects of heat stress on male fertility are evident in developing spermatozoa expressed in ejaculates 18-28 days post-stress in mice. Our objectives were to: (1) assess genetic variation in fertility of heat-stressed male mice and (2) determine response to selection for fertility after heat stress in male mice. ...
Waterland Robert A - - 2006
Transient environmental exposures during mammalian development can permanently alter gene expression and metabolism by influencing the establishment of epigenetic gene regulatory mechanisms. The genomic characteristics that confer such epigenetic plasticity upon specific loci, however, have not been characterized. Methyl donor supplementation of female mice before and during pregnancy permanently increases ...
Brown Lawrence M - - 2006
BACKGROUND: Pharmacist salary and wage surveys have been conducted at the state and national level for more than 20 years; however, it is not known to what extent, if any, wage disparities due to gender still exist. OBJECTIVES: The overall objective of this study was to determine if wage disparities ...
Boseret Géraldine - - 2006
The contribution of social factors to seasonal plasticity in singing behavior and forebrain nuclei controlling song, and their interplay with gonadal steroid hormones are still poorly understood. In many songbird species, testosterone (T) enhances singing behavior but elevated plasma T concentrations are not absolutely required for singing to occur. Singing ...
Khan Christin B - - 2006
The goal of this research was to determine when harbor seal pup vocalizations become sufficiently distinctive to allow individual recognition. A total of 4593 calls were analyzed from 15 captive pups. Nineteen were harsh, broadband, staccato calls used in an aggressive context. The rest were tonal "mother attraction calls," having ...
Dickinson Hayley - - 2007
We investigated the effects of maternal glucocorticoid exposure in the spiny mouse, a precocial species with a relatively long gestation, few offspring, and in which nephrogenesis is complete before birth. We hypothesized that exposure of the fetus to glucocorticoids before the formation of glomeruli would result in adult hypertensive offspring ...
Weatherhead Patrick James - - 2006
Variation in intrauterine exposure to hormones associated with variation in the sex of litter mates has well-established and far-reaching effects on sexual development in some mammals. Research on this phenomenon in reptiles is scant, but suggests that lizards may follow the mammalian model whereas snakes may be affected differently. We ...
Wood S L - - 2006
Our objective was to examine whether mouse lines divergently selected for response to fescue toxicosis differed in the impact of increasing reproductive intensity on growth, final weight or first and second parity reproduction. Resistant (R) and susceptible (S) females were never mated (NR), mated only once (low reproduction, LR), mated ...
Anway Matthew D - - 2006
The current study was designed to examine the actions of a model endocrine disruptor on embryonic testis development and male fertility. Pregnant rats (F0) that received a transient embryonic exposure to an environmental endocrine disruptor, vinclozolin, had male offspring (F1) with reduced spermatogenic capacity. The reduced spermatogenetic capacity observed in ...
Wells Timothy S - - 2006
BACKGROUND: Following the 1991 Gulf War, some veterans expressed concerns regarding their reproductive health. Our objective was to assess whether an association exists between deployment to the 1991 Gulf War and self-reported adverse pregnancy outcomes. METHODS: Using a modified Dillman technique with telephone follow-up, we conducted a survey via a ...
Goel R K - - 2006
Asparagus racemosus (AR) is a herb used as a rasayana in Ayurveda and is considered both general and female reproductive tonic. Methanolic extract of A. racemosus roots (ARM; 100 mg/kg/day for 60 days) showed teratological disorders in terms of increased resorption of fetuses, gross malformations e.g. swelling in legs and ...
Allsop D J - - 2006
Under certain environmental situations, selection may favour the ability of females to adjust the sex ratio of their offspring. Two recent studies have suggested that viviparous scincid lizards can modify the sex ratio of the offspring they produce in response to the operational sex ratio (OSR). Both of the species ...
Buck Louis Germaine M - - 2006
An increasing body of evidence suggests that environmental exposures are adversely influencing female fecundity and fertility. Endocrine-disrupting compounds (EDCs) are of particular concern, due to their ability to interfere with the body's hormonal milieu. An overview of the literature regarding the effect of EDCs on female fecundity and fertility end ...
MacNeil M D - - 2006
The objectives of this research were to partition variation in ovulatory follicle size into genetic and nongenetic components and to assess the utility of ovulatory follicle size as an indicator trait associated with reproductive success in beef cattle. Data were collected during the years 2002 to 2005 from 780 beef ...
Prado Rogilene - - 2006
Adult males of Eidmanacris corumbatai Garcia have reduced tegmina without stridulatory apparatus. For this reason, they developed other means ofintra-specific communication. During courtship, the males use a combination of foreleg drumming and waving of the antennae, in addition to chemical signaling through pheromones. The females become receptive to copulation when ...
Ziegler Toni E TE Wisconsin National Primate Research Center, Madison, WI 53715, USA. - - 2006
Paternal behaviour is critical for the survival of offspring in many monogamous species. Common marmoset (Callithrix jacchus) and cotton-top tamarin (Saguinus oedipus) fathers spend as much or more time caring for infants than mothers. Expectant males of both species showed significant increases in weight across the pregnancy whereas control males ...
Shine Richard - - 2006
Pregnant females modify their thermoregulatory behaviour in many species of viviparous (live-bearing) reptiles, typically maintaining higher and more stable body temperatures at this time. Such modifications often have been interpreted as adaptations to viviparity, functioning to accelerate embryonic development and/or modify phenotypic traits of hatchlings. An alternative possibility is that ...
Naves P - - 2006
The pine sawyer Monochamus galloprovincialis (Olivier) is the vector of the introduced pine wood nematode Bursaphelenchus xylophilus (Steiner & Bührer) Nickle in Portugal, and until recently was considered a secondary forest insect. Under laboratory conditions, a study of biological and reproductive traits of 37 insect pairs was conducted. The longevity ...
Hunt Kathleen E - - 2006
Very little is known about the endocrinology of the baleen whales. The highly endangered North Atlantic right whale (NARW; Eubalaena glacialis) is a good model species, because most NARW individuals are photo-identified with known histories. We used an 125I corticosterone assay, shown to reliably measure cortisol metabolites, to determine glucocorticoid ...
Rülicke T - - 2006
Confronting a recently mated female with a strange male can induce a pregnancy block ('Bruce effect'). The physiology of this effect is well studied, but its functional significance is still not fully understood. The 'anticipated infanticide hypothesis' suggests that the pregnancy block serves to avoid the cost of embryogenesis and ...
Wu Zhuochun - - 2006
This study analysed the relative contributions of three possible determinants to the high sex ratio among newborns in rural China - under-reporting of female births, abortions of female fetuses and excess early female neonatal mortality. A cohort of 3,697 pregnancies collected at village level in 20 rural townships from a ...
Dloniak S M - - 2006
Within any hierarchical society, an individual's social rank can have profound effects on its health and reproductive success, and rank-related variation in these traits is often mediated by variation in endocrine function. Maternal effects mediated by prenatal hormone exposure are potentially important for non-genetic inheritance of phenotypic traits related to ...
Holmes Megan C - - 2006
Low birth weight associates with increased susceptibility to adult cardiometabolic and affective disorders spawning the notion of fetal "programming." Prenatal exposure to excess glucocorticoids may be causal. In support, maternal stress or treatment during pregnancy with dexamethasone (which crosses the placenta) or inhibitors of fetoplacental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), ...
Rosenthal Harriet E S - - 2006
The authors aimed to establish whether interventions designed to reduce intergroup bias could be applied to the stereotype threat domain. In three experiments, the hypothesis was tested that blurring intergroup boundaries would reduce stereotype threat. In the first study, it was found that female participants who thought about characteristics shared ...
Skarda J - - 2006
This study tested and compared the anti-proliferative and proliferative activities of two anti-oestrogens and three anti-progestins on four separate mouse model systems: young intact and adult ovariectomized (OV-X) females, and young intact and adult castrated males. Pure steroidal anti-oestrogen ICI 182,780 (ICI) decreased mammary and uterine growth stimulated by endogenous ...
Zinner Dietmar - - 2006
We present data on sexual maturity in young hamadryas baboon males (Papio hamadryas hamadryas) and its reproductive consequences in a large captive baboon colony. Hamadryas baboons live in a multilevel social system, with one-male units (OMUs) as the smallest social entity. Male leaders of OMUs are believed to monopolize matings ...
Jud Corinne - - 2006
A genetic approach was used to investigate whether the emergence of circadian rhythms in murine pups is dependent on a functional maternal clock. Arrhythmic females bearing either the mPer1Brdm1/Per2Brdm1 or mPer2Brdm1/Cry1-/- double-mutant genotype were crossed with wild-type males under constant darkness. The heterozygous offspring have the genetic constitution for a ...
Diamond David A - - 2006
OBJECTIVE: Sex assignment to newborns with ambiguous genitalia is controversial. Our objective was to determine the attitudes and practices of pediatric urologists on this subject. STUDY DESIGN: A survey of fellows in the Urology Section of the American Academy of Pediatrics was completed by 185/228 (81%). The survey referred to ...
Hayes Tyrone B - - 2006
Atrazine is a potent endocrine disruptor that both chemically castrates and feminizes male amphibians. It depletes androgens in adult frogs and reduces androgen-dependent growth of the larynx in developing male larvae. It also disrupts normal gonadal development and feminizes the gonads of developing males. Gonadal malformations induced by atrazine include ...
Künzle H - - 2007
The gestation length (GL) of Tenrecs (Tenrecinae, Afrotheria) is still uncertain. This lack of knowledge also applies to the lesser hedgehog tenrec, Echinops telfairi, the species most commonly bred and maintained in captivity. The animals used in this study were held under controlled conditions (light, temperature and humidity). In order ...
Cocco Pierluigi - - 2006
We used official statistics of births and stillbirths in 1945-1954 to evaluate reproductive outcomes in the general population following use of DDT during a 1946-1950 anti-malarial campaign in the Italian region of Sardinia. Due to the disruption of registration systems in the World War II years, data in the pre-DDT ...
< 1 2 3 4 5 6 7 8 9 10 11 >