SEARCH · PubMed Health

Results for “Reproductive Period”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources

PubMed1999

[Prevalence of Trypanosoma cruzi infection in opossum (Didelphis albiventris) in Santiago del Estero, Argentina].

The opossum of the genus Didelphis is one of the principal wild reservoirs of Trypanosoma cruzi and is widely distributed in the Western Hemisphere. Didelphis albiventris is the most common marsupial in Amamá and Trinidad, two communities in the province of Santiago del Estero, Argentina. The D. albiventris population is replaced every year, and the opossum normally has two reproductive periods, one at the beginning of the spring and another at the beginning of the summer. The two litters are weaned, and they leave the mother's marsupial pouch to join the population, the first (G1) at the beginning of the summer and the second (G2) at the beginning of the fall. Between 1988 and 1991 409 D. albiventris opossums were studied, and xenodiagnoses showed that 35% of them were infected with T. cruzi. Annual cycles of renewed infection were observed, with prevalences that ranged between 22% and 43%. The acquisition of the parasite occurred over the entire year, from the summer through the spring. The prevalence of infection increased with age. The G1 individuals tended to present higher prevalences than the G2 individuals, probably from being exposed to transmission for a longer period of time. In the first two (younger) age categories for the opossums, G2 individuals showed higher prevalences than did the G1 individuals. This indicates a significant increase in transmission intensity during the fall. Opossums should be regarded as a potential source of T. cruzi entry to the domestic transmission cycle.

Animals↗

PubMed2002

Butterflies from the Uberlândia region, central Brazil: species list and biological comments.

A total of 251 butterfly species were recorded in Uberlândia region, with collecting concentrated mainly in forest areas. Aspects of geographic distribution of some Ithomiinae, as well as interactions of both adults and immatures with plants, and reproduction periods for the more abundant species are discussed. Collections in open, riverside, and wetland areas, as well as the use of bait, should substantially increase the number of species.

Animals↗

PubMed2005

The annual reproductive cycle of the snail Megalobulimus abbreviatus (Bequaert, 1948) (Gastropoda, Pulmonata).

Morphological changes in the sexual organs of the pulmonates were observed throughout a year and correlated with reproductive-cycle periods. Reproductive-organ weights of the snail Megalobulimus abbreviatus were recorded seasonally and gonad sections were analyzed morphologically. The weights were used to obtain the organosomatic index. Mean oocytic diameter and oocytic maturation index were based on gonad sections. It was concluded that M. abbreviatus is an iteroparous snail whose annual reproductive cycle is characterized by mating and egg laying throughout spring and early summer, and also by reproductive system preparation, occurring over the remainder of the summer until the end of winter, for a new breeding season.

Animals↗

PubMed2004

Colonization of rock pile boundary walls in fields by sylvatic triatomines (Hemiptera: Reduviidae) in Jalisco State, Mexico.

Granite rocks is a very abundant material in Mexico because they are used habitually as borders for fields. The current work established the significance of this ecotype as a colonization site for triatomines of the Phyllosoma complex. Seven sites, arbitrary selected, in San Martin de Hidalgo municipality (Mexico) were investigated in April 2002 by using 210 mouse bait-traps left during the night in wall hollows. One hundred and seventy-two triatomines of all life stages were collected from the seven sites. Triatomines adhered to the tape that covered the traps or were found near them, and 36.6% of the traps collected triatomines. The principal species was Triatomia longipennis Usinger (1939) and low numbers of Triatoma picturata Usinger (1939) were found. The nymphal population was very young, probably corresponding to the reproductive period in April (end of the dry season). The infection rate of the triatomines for Trypanosoma cruzi was 49%. Because collecting triatomines in the field is laborious and time-consuming, the mouse bait-trap method found to be practical to assess the population of triatomines within a sylvatic habitat.

Animals↗

PubMed2000

Acanthocephalus tumescens (Acanthocephala, Echinorhynchidae) in Galaxias maculatus (Pisces, Galaxiidae) of Lake Gutiérrez, Patagonia, Argentina.

The seasonal distribution of Acanthocephalus tumescens (Acanthocephala : Echinorhynchidae) among Galaxias maculatus (Pisces : Galaxiidae) in Lake Gutiérrez was studied from March 1994 to June 1996. Acanthocephalus tumescens always occurs in the intestine, has an overdispersed frequency distribution, a similar proportion of sexes, and females are larger than males. Mean intensity and prevalence are low and increase with host length. The pattern of the infection shows seasonality, with recruitment in winter and a reproductive period during spring-summer.

Acanthocephala↗

PubMed2004

Aspects of the ecology and natural history of Paraergasilus rylovi (Copepoda, Ergasilidae) parasitic in unionids of Finland.

The distribution of Paraergasilus rylovi in 17 populations of unionids was investigated. In 1 unionid population, the parasite was studied regarding host age, size, sex, and the reproductive period (occurrence of egg sacs). Results from pooled material from the years 1987--1989 and 1996 (southern Finland, 11 populations) indicated that Anodonta piscinalis (n = 1,359) is the main host (total mean prevalence 71% and intensity +/-SE of infection 16.4+/-0.6). Pseudanodonta complanata (n = 106) was infected occasionally (3% and 1.3+/-0.3), whereas Unio pictorum (n = 108) and U. tumidus (n = 17) were not infected. Results from 17 A. piscinalis populations showed that P. rylovi occurs in southern Finland but not in northern Finland. In A. piscinalis, the mean intensity of infection was higher in lake populations than in river populations. Both host age and length had a negative relationship with the intensity of P. rylovi infection. Host sex did not affect the intensity of infection. Egg sacs of P. rylovi were found from June to August. There was a tendency for higher intensities of infection in autumn. Infection by the digenean Rhipidocotyle fennica had no effect on the intensity of P. rylovi infection.

Analysis of Variance↗

PubMed1986

Regulation of the level of epidermal growth factor by oestrogen in the submandibular gland of female mice.

The concentration of epidermal growth factor (EGF) in the submandibular gland of immature female mice (less than 6 weeks old) was low, ranging from 0.07 to 0.17 pmol (0.4 to 1.0 ng)/mg wet wt, but increasing to 7.61 pmol/mg wet wt by 8 weeks of age. It remained relatively constant up to 24 weeks of age, but thereafter the glandular EGF concentration increased again during the post-reproductive period to reach 62.9 pmol/mg wet wt. In contrast, the glandular EGF content in male mice increased greatly during the first 17 weeks of age to about 310 pmol/mg wet wt, and thereafter remained relatively constant up to 48 weeks of age. Ovariectomy of mature virgin mice markedly increased the glandular concentration of EGF to about 74.4 pmol/mg wet wt 4 weeks after the operation. This increase was suppressed by oestradiol-17 beta administered to ovariectomized mice at a dose of 1 microgram/mouse per day but not by 1 mg progesterone. Histological studies indicated that granular convoluted tubular cells that produced EGF in the submandibular gland were much less abundant in 12-week-old female and in oestrogen-treated ovariectomized mature mice than in 40-week-old female and ovariectomized mature mice. We conclude that oestrogen suppresses the concentration of EGF in the submandibular gland of female mice.

Aging↗

PubMed2002

Statins and menopause.

During the reproductive period, women generally have lower low-density lipoprotein (LDL) cholesterol and higher high-density lipoprotein cholesterol than age- and diet-matched men. However, these possibly antiatherogenic characteristics of lipoproteins are changed to a potentially atherogenic profile after menopause. Menopause-related changes in lipoprotein profile can be corrected by the administration of hormone replacement therapy (HRT). However, the results of recent studies did not show definite benefits of HRT on coronary heart disease-related mortality rates. On the other hand, several large-scale, long-term clinical trials provide evidence for efficacy and safety of HMG-CoA reductase inhibitors (statins) in both men and women. The results of 19 short-term clinical trials using simvastatin, pravastatin, fluvastatin or lovastatin in postmenopausal women are summarised and discussed. All these investigations reported significant reductions in both total and LDL cholesterol levels. The question of whether statin therapy results in a significant decrease in cardiovascular-related mortality rates along with a better quality of life in postmenopausal women remains to be investigated in large-scale, randomised, double-blind, placebo-controlled clinical trials.

Age Factors↗

PubMed2006

Relationships of age at menarche and menopause, and reproductive year with mortality from cardiovascular disease in Japanese postmenopausal women: the JACC study.

BACKGROUND: Early menopause is associated with increased risk of coronary heart disease in Caucasian women. However, this association has not been examined in Asian women. METHODS: We conducted a 10-year cohort study of 37,965 Japanese post-menopausal women aged 40-79 years in the Japan Collaborative Cohort (JACC) Study. Causes of death were determined based on the International Classification of Disease. RESULTS: There were 487 mortality of stroke and 178 mortality of coronary heart disease. Late menarche or early menopause, or shorter duration of reproductive period was not associated with risk of mortality from coronary heart disease. However, compared with women with age at menarche < or =13 years, those with age at menarche > or =17 years tended to have increased risk of mortality from stroke: the multivariable hazard ratio was 1.32 (95% confidence interval [CI]: 0.93-1.87, p = 0.10). Compared with women with age at menopause of > or =49 years, those with age at menopause of <49 years tended to have increased risk of coronary heart disease among women aged 40-64 years; the multivariable hazard ratio was 1.85 (95% CI: 0.92-3.73, p = 0.08). CONCLUSIONS: The possible association between early menopause and coronary heart disease among middle-aged women was consistent with the result of observational studies for Caucasian women, and can be explained by a protective effect of endogenous estrogen on the development of atherosclerosis.

Adult↗

PubMedDate not supplied

[Multiple endometrial polyps in patient undergoing long-term gestagen therapy].

Endometrial polyps represent a limited focal, circumscribed overgrowth of the endometrium. Their aetiopathogenesis has not been completely explained yet. They are often found in perimenopausal women; during the reproductive period they are less common. We present the case of a 32-year-old patient, who came for a check-up to the Gynaecology and Obstetrics Clinic "Narodni Front" because of irregular bleeding. The patient was subjected to hormonal linestrenol therapy, which she had administered herself, without further consultations with her gynaecologist, during the previous 10 years. Complete diagnostic examinations were performed. Contrast sonohysterography enabled the visualisation of multiple polyps inside the uterine cavity, which were confirmed by histopathological analysis of material obtained via explorative curettage. Histopathological material contained over 30 endometrial polyps. A control check-up after one month, as well as subsequent quarterly check-ups, resulted in normal findings. Analysis of the described case has indicated that the loss of sensitivity of progesterone receptors in endometrial cells is possible if there is a continuous presence of progesterone agonists in circulation, as is true of linestrenol in this case. The loss of sensitivity of progesterone receptors upsets normal hormonal activity during the secretory phase of the menstrual cycle, leading to copious, irregular bleeding. These changes may, however, have even deeper effects. More recent research shows that, if the agent causing the loss of sensitivity of the receptors is present in circulation over a longer time period, changes may also appear at the DNA molecular level, i.e. in the cell genome itself. This, in turn, may lead to the beginning of the process of oncogenesis and the formation of tumourous tissue.

Adult↗

PubMed2006

Differential effects of continuous and intermittent 17beta-estradiol replacement and tamoxifen therapy on the prevention of glomerulosclerosis: modulation of the mesangial cell phenotype in vivo.

Female ROP Os/+ mice are partially protected by endogenous estrogens against progressive glomerulosclerosis (GS) during their reproductive period; however, ovariectomy accelerates GS progression. We examined the effects of continuous and intermittent 17beta-estradiol (E(2)) replacement and tamoxifen therapy on the development of GS in ovariectomized (Ovx) ROP Os/+ mice. Continuous E(2) replacement (CE(2)) throughout 9 months prevented microalbuminuria and excess extracellular matrix accumulation in Ovx ROP Os/+, not only compared to placebo-treated Ovx mice but also in comparison to intact female ROP Os/+. Tamoxifen had a similar effect, but of lesser magnitude. Intermittent 3-month on-off-on E(2) did not reduce the kidney changes. Mesangial cells (MCs) from CE(2) mice maintained their estrogen responsiveness. E(2) in vitro prevented transforming growth factor-beta1 stimulation of a Smad-responsive reporter construct and increased MMP-2 expression and activity in MCs isolated from CE(2) mice. MCs from mice on either placebo or intermittent E(2) treatment did not respond to added E(2), consistent with a stable alteration of their estrogen responsiveness. Tamoxifen protection against GS was less pronounced in ROP Os/+ mice. Thus, prolonged estrogen deficiency promotes GS and renders MCs insensitive to subsequent estrogen treatment. This underscores the importance of continuous estrogen exposure for maintaining glomerular function and structure in females susceptible to progressive GS.

Albuminuria↗

PubMed1981

Effects of estrogen deficiency in women castrated when young.

In earlier studies on the effects of castration, most of the women had been operated on late in the reproductive period of life. In the present material all the 142 women had been oophorectomized between the ages of 15 and 30 years because of advanced salpingitis. Not only the tubes but also the ovaries had been radically removed. The series was analyzed in respect of causes of death, survival, morbidity, osteoporosis and hormonal state. Complete oophorectomy was found to be followed by (i) a significant increase in the frequency of coronary heart diseases; (ii) an increase in serum cholesterol and triglyceride levels, most significantly in those aged below 60-65 years; (iii) an increase incidence of fractures; (iv) in increased frequency of nervous disorders of psychological rather than endocrinological origin.

Adult↗

PubMed1992

Uterine torsion in pregnancy.

Torsion of the pregnant uterus is defined as rotation more than 45 degrees around the long axis of the uterus. Uterine torsion is observed in all age groups of the reproductive period, in all parity groups, and at all stages of pregnancy. Torsion from 60 degrees to 720 degrees has been described. It is not possible to clarify why uterine torsion occurs, but numerous abnormalities have appeared with uterine torsion; most often, abnormal fetal presentation, myoma uteri and uterine malformations. The most usual symptoms of uterine torsion are birth obstruction, abdominal pain, vaginal bleeding, shock, and urinary and intestinal symptoms. Eleven percent are asymptomatic. The treatment in the earlier months of pregnancy is immediate laparotomy and detorsion of the uterus and, if practicable, adjunct surgery to eliminate the possible etiologic factors. Near term or during labor cesarean section is carried out, and elimination of the possible etiologic factors. The fetal and maternal mortality rates since 1976 are 12% and 0% respectively.

Adult↗

PubMed1982

Coeliac disease, fertility, and pregnancy.

The effect of coeliac disease and its treatment on fertility and pregnancy in 74 patients is reported. Those on a normal diet had a shorter reproductive period, were relatively infertile, and had a higher incidence of spontaneous abortions than those on a gluten-free diet. Although maternal health did not appear to be seriously impaired by pregnancy in undiagnosed coeliacs, those on a gluten-free diet had significantly fewer symptoms and had heavier babies.

Abortion, Spontaneous↗

PubMed1986

Cytochemistry and ultrastructure of normal and neoplastic cells exfoliated from the human uterine cervix.

Cells exfoliated from the uterine exocervix from normal women at different stages of the reproductive period and from patients with invasive carcinoma were studied. Cell pellets were fixed in aldehydes and two different concentrations of OsO4, and embedded in methacrylate or Epon. Semithick sections were used for general light microscopic study and for the visualization of glycogen. Ultrathin sections were used for conventional electron microscopy, high resolution analysis of the plasma membrane, and the demonstration of glycogen and cell surface glycoconjugates by the Thiery method. Semithick sections stained with the Thiery method and viewed under the electron microscope were used for the study of surface projections. Based on the size, shape, nuclear characteristics, amount and distribution of glycogen, type of surface protrusions, density and distribution of surface glycoconjugates, and plasma membrane fine structure, the cells exfoliated from all normal uterine cervices were grouped into five cell types. It is suggested that these types correspond to cells located in the different layers of the exocervical epithelium and, consequently, represent different degrees of normal differentiation. The plasma membrane of carcinoma cells shared most of the characteristic of that of the least differentiated normal cells, indicating an early deviation of the differentiation process in carcinoma cells.

Carcinoma, Squamous Cell↗

PubMed1993

Melanoma and pregnancy. A review.

In the last half-century the incidence of cutaneous malignant melanoma has increased all over the world according to available reports. No association between risk of melanoma and age at menarche, first birth, menopause or duration of reproductive period has been proven so far. Studies on the effect of parity on relative risk and survival have given divergent results with multiparous women possibly having a better prognosis than nullipara. Women with melanoma diagnosed during pregnancy tend to have thicker tumours, shorter disease-free interval and, maybe, lower 10-year survival rate than non-pregnant matched controls. There is no conclusive evidence that therapeutic abortion improves the cure rate. Multivariate analysis has failed to unveil impaired prognosis in women who become pregnant subsequent to diagnosis.

Adolescent↗

PubMed1983

Metabolism and growth of chickens before and after hatch in relation to incubation temperatures.

Chick embryos were incubated at 35.8 C from days 1 to 10 and at 37.8 C from day 11 to hatching. Control embryos were incubated at 37.8 C. Other environmental conditions were standardized. Embryos incubated at 35.8 C showed compensatory growth when compared to embryos of the control group and showed a higher heat production (kJ/embryo/hr) expressed as a linear function of dry embryo weight (g) or incubation time (days). After hatching, the compensatory growth of the chickens incubated at 35.8 C (days 1 to 10) continued, as demonstrated by analyses of the weight of the body, liver, and the gastrointestinal tract. The same animals produced more heat per unit of time and body weight. Adult hens from this group showed a trend for higher heat production per unit body weight as well as a higher dry matter content. These results suggest a link between in ovo environmental conditions, growth processes, and metabolic level up to the reproduction period of domestic fowl.

Animals↗

PubMed1983

Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 5. Correlated responses in adult body weight, liver weight, ovarian follicle production, and carcass composition of laying hens.

Laying female quail of five strains (R-1, randombred control; HP and LP, high or low concentration of egg yolk very low density lipoprotein (VLDL) precursor in laying females: HW and LW, high or low 4-week body weight) were sampled after 120 days of egg production for body weight, liver weight, ovarian follicle production, and carcass composition. Body weight change during the reproductive period was associated with starting body weight, but not with yolk VLDL precursor (total plasma phosphorus). Egg production was slightly depressed in both the HW and HP strains. Liver weight was associated with body weight. Percent dry matter of liver was not different between strains. Liver as a percentage of body weight was slightly greater in the HP strain. Egg and yolk weights were associated with body weight but not with concentration of yolk VLDL precursor. Ovarian follicle number and weight were also influenced by body weight but not by concentration of yolk VLDL precursor. Carcass composition was influenced by body weight. The larger HW strain contained more fat and less protein than the smaller LW strain after 120 days of egg production.

Animals↗