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Results for “Reproductive Period”

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At least 199 records · Page 11Linked to original sources

PubMed2002

Delayed gametogenesis of Mya arenaria in the Saguenay fjord (Canada): a consequence of endocrine disruptors?

The Saguenay fjord located in Canada on the north coast of the Saint-Lawrence Estuary, is well known for its multiple contaminations following a linear distribution upstream to downstream. Mya arenaria is well established in the fjord and potentially exposed to persistent sediment contamination as an endobenthic bivalve. From May to October 1997, clams energy storage and utilization in the gonad was shown to be closely linked with reproduction. Wherever the sampling site location in the fjord, a seasonal pattern is evident for lipid and glycogen levels in the gonad, this, reflecting the vitellogenic process. Nevertheless, in comparison with energy status and gametogenesis of clams collected on the north coast of the Saint-Lawrence Estuary, clams located in the fjord have to face limited nutritive conditions resulting in a single and shorter reproductive period. Although environmental factors could explain differences in physiological condition and reproductive status observed between clams from the fjord and the estuary, our results can discriminate clams from the upper part of the fjord, according to a delayed gametogenesis, concomitant with significant higher gonad glycogen concentrations observed in June 1996 and 1997. A persistent dysfunction of a vitellogenic process is suspected to be due to the exposure to anti-estrogenic contaminants.

Animals↗

PubMed2006

Divergence of reproductive phenology under climate warming.

Because the flowering and fruiting phenology of plants is sensitive to environmental cues such as temperature and moisture, climate change is likely to alter community-level patterns of reproductive phenology. Here we report a previously unreported phenomenon: experimental warming advanced flowering and fruiting phenology for species that began to flower before the peak of summer heat but delayed reproduction in species that started flowering after the peak temperature in a tallgrass prairie in North America. The warming-induced divergence of flowering and fruiting toward the two ends of the growing season resulted in a gap in the staggered progression of flowering and fruiting in the community during the middle of the season. A double precipitation treatment did not significantly affect flowering and fruiting phenology. Variation among species in the direction and magnitude of their response to warming caused compression and expansion of the reproductive periods of different species, changed the amount of overlap between the reproductive phases, and created possibilities for an altered selective environment to reshape communities in a future warmed world.

Climate↗

PubMed2001

A serial study of heart function during pregnancy, lactation and the dry period in dairy goats using echocardiography.

Echocardiography and Doppler measurements were performed to investigate changes in heart dimensions and function during pregnancy, lactation and the non-pregnant, non-lactating (dry) period in dairy goats. Eight Swedish domestic goats (Capra hircus) were studied with two-dimensional (2DE), M-mode and continuous wave Doppler measurements. Cardiac dimensions did not differ between periods. The mean cardiac outputs were 35 and 28% greater during pregnancy and lactation, respectively, vs. the dry period. Arterial blood pressure (measured by telemetry) did not differ between reproductive periods before echocardiographic measurements, but became elevated during the measurements, with the smallest rise during lactation. Heart rate was elevated during pregnancy and increased further during echocardiographic measurements, but was not elevated during the other periods. The cranial location of the heart influenced the selection of examination window and caused some difficulties in positioning the ultrasound transducer. This may have led to underestimation of the velocity trace integral and therefore to underestimation of cardiac output. However, our values were within the range of these obtained with dye- and thermodilution methods. The goats tolerated the investigations well during lactation and the dry period, but showed increased blood pressure and heart rate during pregnancy. Therefore, the non-invasive and safe echocardiographic-Doppler method appears to be a good alternative for studies of heart dimensions and function during lactation and the dry period in the dairy goat.

Animals↗

PubMed2005

Female reproductive cycle and obsessive-compulsive disorder.

BACKGROUND: The aim of our study was to assess whether there is a relationship between reproductive cycle events and the initiation or changes in symptoms of obsessive-compulsive disorder (OCD). METHOD: Forty-six female outpatients meeting DSM-IV criteria for OCD completed a semistructured interview at our OCD unit to assess the relationship between reproductive cycle events and OCD. Dates of data collection were from January 2001 to December 2003. RESULTS: In our sample, OCD onset occurred in the same year as menarche in 22% (N = 10), at pregnancy in 2% (N = 1), at postpartum in 7% (N = 3), and at menopause in 2% (N = 1). Worsening of preexisting OCD was reported by 20% of patients (9/45) at premenstruum, 8% (1/12) at pregnancy, 50% (6/12) at postpartum, and 8% (1/12) at menopause. The number of premenstrual mood symptoms, which included anxiety, irritability, mood lability and depressed mood, was associated with both premenstrual worsening of OCD (OR = 5.1, p < .01) and onset or worsening of OCD at postpartum (OR = 2.7, p < .05). Patients with an onset or worsening of OCD at postpartum also more frequently reported pre-menstrual worsening of OCD and previous history of major depressive disorder, including postpartum depression (p < or =.05 for all). CONCLUSION: In a substantial number of patients, the onset or worsening of OCD was related to reproductive cycle events, especially at menarche and postpartum. Certain women with OCD seem to be vulnerable to worsening of OCD at different reproductive periods that imply hormonal fluctuations, and premenstruum and post-partum were the 2 reproductive events with a greater vulnerability. Those patients whose OCD symptoms appeared to be related to reproductive events also exhibited a greater history of mood symptoms (premenstrual depression and major depressive episodes).

Adolescent↗

PubMed2006

Reinstatement of "germinal epithelium" of the ovary.

BACKGROUND: The existing dogma that the former term ovarian "germinal epithelium" resulted from a mistaken belief that it could give rise to new germ cells is now strongly challenged. DISCUSSION: Two years ago, a research group of the University of Tennessee led by Antonin Bukovsky successfully demonstrated the oogenic process from the human ovarian covering epithelium now commonly called the ovarian surface epithelium. They showed the new oocyte with zona pellucida and granulosa cells, both originated from the surface epithelium arising from mesenchymal cells in the tunica albuginea, and stressed that the human ovary could form primary follicles throughout the reproductive period. This gives a big impact not only to the field of reproductive medicine, but also to the oncologic area. The surface epithelium is regarded as the major source of ovarian cancers, and most of the neoplasms exhibit the histology resembling müllerian epithelia. Since the differentiating capability of the surface epithelium has now expanded, the histologic range of the neoplasms in this category may extend to include both germ cell tumors and sex cord-stromal cell tumors. SUMMARY: Since the oogenic capability of ovarian surface cells has been proven, it is now believed that the oocytes can originate from them. The term "germinal epithelium", hence, might reasonably be reinstated.

Animals↗

PubMedDate not supplied

[Seasonal dynamics of the population structure of Sphaerostomum globiporum (Trematoda: Opecoelidae) maritae in Ladoga Lake].

Data on the seasonal dynamics of population structure is obtained for the first time for the Trematode species Sphaerostomum globiporum from roach Rutilus rutilus (L) in Ladoga Lake, which situates in the northern limit of the distribution range of this species. The parasites infest the host in October and leave it from the end of July to the beginning of August. The maximum of the magnitude of the Trematode population falls on spring, and the minimum is observed in summer. In August and September roach is free of the parasites. It is established that the period of maturing occupies 10 months for S. globiporum from roach in Ladoga Lake. The prereproductive period takes 5 months and comes to the end in February. The reproductive period occupies 5 months too. Although these two periods of the parasite's life cycle do not separated from each other clearly, an overlapping of two generations was not observed, unlike the case of more southern water bodies.

Animals↗

PubMed1975

Effect of Altered pO(2) in the Aerial Part of Soybean on Symbiotic N(2) Fixation.

Dry matter accumulation, nitrogen content and N(2) fixation rates of soybean (Glycine max [L.] Merr. cv. Wye) plants grown in chambers in which the aerial portion was exposed to a pO(2) of 5, 10, 21, or 30% and a pCO(2) of 300 mul CO(2)/l or a pO(2) of 21% and a pCO(2) of 1200 mul CO(2)/l during the complete growth cycle were measured. Total N(2)[C(2)H(2)] fixed was increased by CO(2)/O(2) ratios greater than those in air and was decreased by ratios smaller than those in air; the effects on N(2) fixation of decreased pO(2) or elevated pCO(2) were quantitatively similar during the period of vegetative growth. Decreased pO(2) produced a smaller increase then elevated pCO(2) during the reproductive period, presumably because of the decreased sink activity of the arrested reproductive growth under subambient pO(2). At a pO(2) of 5% and a pCO(2) of 300 mul CO(2)/l total N(2) fixed was increased 125% and per cent nitrogen content in the vegetative parts was increased relative to air while that in the seed was decreased. Dry matter production was increased and reproductive growth was arrested as previously reported for plants receiving only fertilizer nitrogen. At a pO(2) of 30% and a pCO(2) of 300 mul CO(2)/l total N(2) fixed was decreased 50% and per cent nitrogen content in the vegetative part was increased relative to air while that in the reproductive structures was unaffected. Dry matter production was similarly decreased in both vegetative and reproductive structures. These effects of altered pO(2) in the aerial part on N(2) fixation are consistent with the hypothesis that the amount of photosynthate available to the nodule may be the most significant primary factor limiting N(2) fixation while sink activity of the reproductive structures may be a secondary factor.

Journal Article↗

PubMed1995

Dietary exposure of mink to carp from Saginaw Bay, Michigan. 1. Effects on reproduction and survival, and the potential risks to wild mink populations.

Carp (Cyprinus carpio) collected from Saginaw Bay, Michigan, containing 8.4 mg total polychlorinated biphenyls (PCBs)/kg and 194 ng of 2,3,7,8-tetrachloro-dibenzo-p-dioxin equivalents (TEQs)/kg, were substituted for marine fish at levels of 0, 10, 20, or 40% in the diets of adult ranch mink (Mustela vison). The diets, containing 0.015, 0.72, 1.53, and 2.56 mg PCBs/kg diet, or 1.03, 19.41, 40.02, and 80.76 ng TEQs/kg diet, respectively, were fed to mink prior to and throughout the reproductive period to evaluate the effects of a naturally-contaminated prey species on their survival and reproductive performance. The total quantities of PCBs ingested by the mink fed 0, 10, 20, or 40% carp over the 85-day treatment period were 0.34, 13.2, 25.3, and 32.3 mg PCBs/mink. respectively. The corresponding quantities of TEQs ingested by the mink over the same treatment period were 23, 356, 661, and 1,019 ng TEQs/mink, respectively. Consumption of feed by mink was inversely proportional to the PCB and TEQ content of the diet. The diet containing Saginaw Bay carp caused impaired reproduction and/or reduced survival of the kits. Compared to controls, body weights of kits at birth were significantly reduced in the 20 and 40% carp groups, and kit body weights and survival in the 10 and 20% carp groups were significantly reduced at three and six weeks of age. The females fed 40% carp whelped the fewest number of kits, all of which were stillborn or died within 24 hours. Lowest observable adverse effect levels (LOAEL) of 0.134 mg PCBs/kg body weight/day or 3.6 ng TEQs/kg body weight/day for adult female mink were determined. The potential effects of exposure of wild mink to contaminated Great Lakes fish were assessed by calculating "maximum allowable daily intakes" and "hazard indices" based on total concentrations of PCB residues in several species of Great Lakes fish and mink toxicity data derived from the study.

Animals↗

PubMedDate not supplied

Consanguinity and reproductive behaviour in a tribal population 'the Baiga' in Madhya Pradesh, India.

We have studied the marriage pattern and reproductive behaviour in a single Central Indian primitive tribe, the Baiga. Parents were consanguineous in 34% of marriages (19.2% mother's brother's daughter (MBD), 13.1% father's sister's daughter (FSD) and 1.7% were double first cross-cousins (DFCC). Fertility levels were significantly higher (p < 0.05) in related couples (4.7 offspring/couple) than unrelated couples (4.2/couple). Mortality (up to 20 years) was 19%. In the offspring of consanguineous couples it was higher (19.7%) than in the offspring of unrelated couples (18.6%) but the difference was not statistically significant. In consanguineous couples the reproductive period was longer than in unrelated couples, probably to allow compensation for increased reproductive losses (infant and childhood deaths). The level of social as compared to genetic parenting was about 35% as measured by tracking the inheritance of sickle gene, and allowance must be made for this in assessing the influence of consanguineous marriage on fertility and mortality.

Adolescent↗

PubMed2005

[Population statistics of Triatoma rubrovaria in laboratory].

OBJECTIVE: To obtain T. rubrovaria population parameters in order to describe its demographic characteristics. METHODS: The study was carried out in the laboratory of Arthropods, Corrientes, Argentina, from October 2000 to February 2003. Eggs were grouped to form five 100-egg cohorts. Insects were fed on chickens (Gallus domesticus). The cohorts were monitored weekly and kept under controlled temperature (28 +/- 3 degrees C) and relative humidity (63 +/- 10%). A life table was constructed and other vital statistics were calculated and recorded. RESULTS: Higher mortality was recorded in the first through the fourth nymphal stadium. A constant decrease was seen from the fifth nymphal instar. Life expectancy dropped linearly after overcoming the critical stages. Adults mean survival was 50.2 weeks. The first oviposition was after 40.6 weeks. The fecundity was 859.6 eggs with an average 22.8 eggs per female. The reproductive period was 37.7 weeks. The generation time was 55.3 weeks and the net reproduction rate was 133.7. The intrinsic rate of weekly increment was 0.088. In a stable age distribution the population would be composed of 25.3% eggs, 72.3% nymphs and 2.4% adults. Adults accounted for more than 70% of the total reproductive value. CONCLUSIONS: Triatoma rubrovaria had a long survival as imago, a late first reproduction and a low intrinsic rate of natural increase.

Animals↗

PubMed2002

Seasonal changes in testicular steroidogenesis in the toad Bufo arenarum H.

The biosynthesis of androgens in Bufo arenarum takes place through the 5-ene pathway that includes 5-androstane-3beta,17beta-diol as intermediate in testosterone biosynthesis. Besides testosterone and 5alpha-dihydrotestosterone, testes are able to synthesize 5alpha-pregnan-3,20-dione and several 3alpha- and 20alpha-reduced derivatives. Steroid biosynthesis changes during the breeding period (spring and early summer), turning from androgen to C21 steroid production. During the reproductive season, the production of progesterone, 5alpha-pregnan-3alpha,20alpha-diol, 3alpha-hydroxy-5alpha-pregnan-20-one, and 5alpha-pregnan-3,20-dione increases significantly. The function of most of these steroids in amphibians remains unknown. However, 5alpha-androstan-3alpha,17beta-diol and 3alpha-hydroxy-5alpha-pregnan-20-one were shown to be neuroactive in mammals, modulating sexual behavior. Thus, 5alpha/3alpha-reduced steroids could be involved in the regulation of the reproductive behavior in B. arenarum, a species with a dissociated reproductive pattern. Percentage contribution of each enzymes to the total metabolism reveals that neither 3beta-hydroxysteroid dehydrogenase/isomerase nor 5alpha-reductase change throughout the reproductive cycle. However, a strong reduction in 17-hydroxylase-C(17-20) lyase activity occurs in the reproductive season, suggesting that this enzyme could represent a key enzyme in the regulation of the seasonal change of steroidogenesis. Also, 3alpha-hydroxysteroid dehydrogenase and 20-hydroxysteroid dehydrogenase activities increase during the reproductive period, implying that steroid metabolism is clearly focused on C21-reduced steroids.

Androgens↗

PubMed2006

Huge leiomyoma in a woman with Down syndrome: a case report.

BACKGROUND: For patients with Down syndrome, the reproductive period is becoming longer in relation to the increasing lifetime. Thus, the possibility of reproductive disorders is also increasing. CASE: A 37-year-old woman with trisomy 21 was hospitalized with uterine myomatosis, which was spreading to the umbilicus. Total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed, and estrogen replacement was given after surgery. CONCLUSION: The incidence of solid tumors in Down syndrome patients is extremely rare or nonexistent. This case calls attention to reproductive pathology in long-lived women with Down syndrome.

Adult↗

PubMedDate not supplied

[Hashimoto disease and hypothyroidism in child-bearing period--essential problem for woman and her child].

Hashimoto disease is the most frequent cause of women's hypothyroidism in the reproductive period. It can, both directly and indirectly, influence the fertility, pregnancy, and fetus development. Nevertheless congenital hypothyroidism is very occasionally the consequence of chronic autoimmune thyroiditis. The neonatal hypothyroidism screening makes the early thyroxin treatment possible and prevents the development of complications from central nervous system. The authors showed main problems of Hashimoto disease in women during pregnancy as well as pregestational and postgestational period. The reasons of congenital hypothyroidism taking into account both iodine deficiency and excess were also presented.

Congenital Hypothyroidism↗

PubMed1996

Development and fecundity of Dermatophagoides farinae (Acari: Pyroglyphidae).

Duration of the life cycle at 16, 23, 30, and 35 degrees C and fecundity at 23 degrees C and 75% RH were determined for the American house dust mite, Dermatophagoides farinae Hughes. Lengths of the life cycles at 23 and 30 degrees C were 35.6 +/- 4.4 and 17.5 +/- 1.2 d, respectively. Few eggs completed development to the adult stage at 16 and 35 degrees C. At 23 degrees C and 75% RH, the preoviposition period was 3.7 +/- 1.1 d following emergence of the female from the tritonymph. The average reproductive period was 34.0 +/- 10.7 d with a mean total of 65.5 +/- 17.4 eggs produced per female. Female longevity after cessation of egg production was 63.3 +/- 64.6 d.

Animals↗

PubMed1991

Effect of evening primrose oil as food supplement on reproduction in the blue fox.

Addition of evening primrose oil (EPO) to a blue fox diet in the reproduction period was evaluated in an experiment with 2 groups, each of 12 male and 25 female blue foxes, regarding the effects on reproductive performance. The experiment was carried out as a field trial and the experimental period lasted from March 10 until the end of the mating season (males) or early July (females). During this period the control group was fed the standard diet of the farm and the experimental group was fed the same diet supplemented with 4.5 g EPO and 2.5 mg zinc sulphate per animal and day. An addition of 10 mg vitamin E per 500 mg EPO was made. The results were evaluated regarding male and female treatment effects. There was an increased rate of abortions in the EPO-group, but simultaneously a non-significant decrease in the frequency of barren females, resulting in a similar level of females without litters in both groups. A tendency for increased litter size in the EPO group was found, mainly as an effect of male treatment, which might indicate an effect on semen quality.

Abortion, Veterinary↗

PubMed1989

Reproductive toxicity of three phthalic acid esters in a continuous breeding protocol.

A continuous breeding protocol was utilized to examine the reproductive toxicity of three phthalate esters. CD-1 mice were given diets with either di-n-propyl phthalate (DPrP: 0.0, 1.25, 2.5, or 5.0%), di-n-pentyl phthalate (DPP: 0.0, 0.5, 1.25, or 2.5%), or di-n-octyl phthalate (DOP: 0.0, 1.25, 2.5, or 5.0%). Both male and female mice (20 pairs per treatment group, 40 pairs of control animals) were dosed for 7 days prior to and during a 98-day cohabitation period. Reproductive function was evaluated during the cohabitation period by measuring number of litters per pair, live pups per litter, and pup weight. There was no apparent effect on reproductive function in the animals exposed to DOP at dose levels sufficient to cause a significant increase in liver weight. Both DPP and DPrP were toxic to the reproductive system as evidenced by a complete inhibition of fertility at 1.25 and 2.5% DPP or 5.0% DPrP, and reduced fertility (litters/pair and live pups/litter, 0.5% DPP; live pups/litter, 2.5% DPrP). Toxicity of DPP had a strong male component and female component, whereas DPrP was more toxic to the female than the male reproductive system. DPP and DPrP treatment was associated with decreased body weight, increased liver weight, decreased testis and epididymis weights, decreased epididymal sperm concentration, and elevated seminiferous tubule atrophy. A comparison of seven phthalate esters tested using this continuous breeding protocol indicates the relative order of reproductive toxicity as diethylhexyl, dihexyl, dipentyl, dibutyl, dipropyl; diethyl and dioctyl are nontoxic.

Animals↗

PubMed1995

Short communication: breast parenchymal patterns and their changes with age.

In studies on mass screening, it has often been reported that tumours in breasts with dense parenchyma are difficult to detect and may have a more advanced stage at diagnosis. Shorter rescreening intervals have been suggested for these women but, before recommending such a strategy, it is important to investigate how often dense breast parenchyma (P2 and DY patterns according to Wolfe) is actually present in a screening population and to what extent these patterns change with age. The prevalence of dense breast parenchyma (P2 and DY) in our study population was 33% at first examination (n = 2581), which is fairly low compared with other screening populations. Its presence was strongly, inversely age-dependent. Breast patterns of 1177 women, aged 35-85 years, were followed for 12 years. In 39% (182/461) of the women with a P2 or DY pattern at their first examination, regression to a lucent pattern (N1 and P1) occurred over the years. The majority of these women were assumed to have reached menopause in the follow-up period. These findings support the hypothesis that the presence of dense breast parenchyma is related to the reproductive period and indicate that shortening the rescreening intervals would be most effective in pre-menopausal age groups.

Adult↗

PubMed2001

[Coeliac disease and problems associated with reproduction].

Coeliac patients taking a normal diet have a shortened reproductive period with delayed menarche and early menopause. Many studies have shown that coeliac women are susceptible to reproductive difficulties such as infertility and miscarriages. The disease is also associated with low birth weight in babies and short duration of breast feeding. Folic acid deficiency is present in the majority of patients with untreated disease and it might be a maternal risk factor for neural tube defects and orofacial clefts. Coeliac men may have reversible infertility, and as in women, if gastrointestinal symptoms are mild or absent the diagnosis may be missed. It is important to make diagnosis because the giving of gluten free diet may result in conception and favourable outcome of pregnancy.

Abnormalities, Multiple↗