Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “First Birth”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,747 records · Page 97Linked to original sources
PubMed2006

Hormonal and reproductive factors and risk of glioma: a prospective cohort study.

The etiology of glioma, the most commonly diagnosed malignant brain tumor among adults in the United States, is poorly understood. Given the lower incidence rate of glioma in women than in men, it has been hypothesized that reproductive and hormonal factors may be involved in the etiology of glioma. We conducted a secondary analysis of data from the National Breast Screening Study, which included 89,835 Canadian women, aged 40-59 years at recruitment between 1980 and 1985. Linkages to national cancer and mortality databases yielded data on cancer incidence and deaths from all causes, respectively, with follow-up ending between 1998 and 2000. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals (CI) for the association between hormonal and reproductive factors and risk of glioma. During a mean of 16.4 years of follow-up, we observed 120 incident glioma cases. Compared with women with a relatively early age at menarche (< or =12 years), women who were 13-14 years of age at menarche had a 64% increased risk of glioma (95% CI = 1.01-2.65), and women who were older than 14 years of age at menarche had a 66% increased risk of glioma (95% CI = 0.86-3.20, p(trend) = 0.06). Age at first live birth, parity, menopausal status, use of oral contraceptive and use of hormone replacement therapy were not associated with altered glioma risk in our study population. Additional prospective studies are needed to confirm our findings.

Adult↗
PubMed1991

Incidence of histologic types of uterine sarcoma in relation to menstrual and reproductive history.

To determine whether the occurrence of one or more histologic types of uterine sarcoma is related to events in a woman's reproductive life, a population-based case-control study was conducted. One-hundred sixty-seven women newly diagnosed with uterine sarcoma among residents of 6 geographic regions were compared to 208 women selected at random from the same populations with regard to histories of menstruation, pregnancy and childbearing, and breast feeding, as reported during a telephone interview. Compared to women whose menstrual periods began at age 13, women whose menses began earlier were at increased risk of leiomyosarcoma (OR = 2.0, 95% CI 0.9, 4.3); other histologic types were less strongly associated with early age at menarche. Women with leiomyosarcoma and endometrial stromal sarcoma, but not malignant mixed Müllerian tumors, tended to have ceased menstruating 2-3 years later than controls. None of the histologic types was clearly related to parity or to age at first live birth, but each was inversely related to age at last live birth. Associations were observed between leiomyosarcoma and histories of an induced abortion (OR = 4.2, 95% CI 1.2, 14.2) and of breast feeding after a live birth (OR = 0.5, 95% CI 0.3, 1.0); these relationships were not observed for other morphologic variants. These results suggest possible similarities and differences in menstrual and reproductive risk factors among histologic types of uterine sarcoma, and between these malignancies and the more common breast, endometrial and ovarian carcinomas.

Adult↗
PubMed1993

Development of breast cancer chemopreventive drugs.

Breast cancer is the second highest cause of cancer mortality (19%) estimated for U.S. women in 1993 and accounts for the highest proportion of new cancer cases (32%) in this population. The rate of documented cases increased during the early 1970s and again in 1980-87, probably due to early mammographic detection. Increased knowledge of personal risk may also have been a consideration; however, 60% of women diagnosed with breast cancer have no known risk factor(s), such as family history, early age at menarche, late age at menopause, nulliparity, late age at first live birth, socioeconomic status, contraceptive use, postmenopausal estrogen replacement, or high fat intake. To prevent cancer, one strategy undertaken by the NCI is cancer chemoprevention, or intervention with chemical agents at the precancer stage to halt or slow the carcinogenic process. An objective of the NCI, DCPC is to develop promising cancer chemopreventive chemical agents as drugs for human use. Briefly, the process begins with identification of potential agents (e.g., pharmaceuticals, natural products, minor dietary constituents) from surveillance and analysis of the literature and from in vitro prescreen assays. Data on both efficacy (i.e., biological activities that either directly or indirectly indicate inhibition of carcinogenesis) and toxicity are gathered these sources. Various criteria are used to select and prioritize agents for entry into the NCI, DCPC preclinical testing program. The program begins with battery of in vitro efficacy screens using both animal and human cells to select agents for further testing; agents positive in these assays are considered for further testing. In the assay used for breast cancer chemoprevention, 7,12-dimethylbenz(a)anthracene (DMBA)-induced mouse mammary organ culture, 64 chemicals have inhibited formation of hyperplastic alveolar-like nodules. A panel of organ-specific animal screening assays are then used to assess efficacy in vivo. Two assays relevant for breast cancer chemoprevention are inhibition of N-methyl-N-nitrosourea- and DMBA-induced rat mammary gland carcinogenesis. Of 89 agents tested, 29 have inhibited cancer incidence, multiplicity, or both in at least one of the mammary assays; 21 agents are currently on test. Highly promising agents are then placed in traditional preclinical toxicity tests performed in two species. Finally, the most promising and least toxic agents enter clinical trials. Phase I clinical trials are designed to investigate human dose-related safety and pharmacokinetics of the drug. Phase II trials are small scale, placebo-controlled studies designed to determine chemopreventive efficacy and optimal dosing regimens.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Effect of changing from a short-day to long-day photoperiod on the breeding season of the brushtail possum (Trichosurus vulpecula).

In Queensland, possums (Trichosurus vulpecula) in the wild and in captivity first give birth during March and April and continue to give birth throughout the year until November. The possum has a gestation length of 17.5 days, gives birth to one young, and lactation continues for approximately 180 days. If the newborn possum is removed during the breeding season, the possum will ovulate approximately 9 days later and give birth approximately 26 days after removal of the pouch young (RPY). Repeated RPY may be used to determine the duration of the breeding season. In this study, the effect on the breeding season of a marked change in photoperiod From a short-day to a long-day was examined by comparing three groups of possums in different photoperiods for 13 months. One group of five female and two mail possums (group A) was housed in a natural photoperiod and a second group (B) was housed in a short-day photoperiod (10 h light: 14 h dark) throughout the study. The third group (C) was housed in a short-day photoperiod until each possum gave birth, the pouch young was removed, and the possum transferred to a long-day photoperiod room (14 h light: 10 h dark) for the remainder of the study. The possums held in a natural photoperiod, group A, gave birth to a total of 27 births in the one breeding season from March to October.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

Ontogenesis of the scapula in marsupial mammals, with special emphasis on perinatal stages of didelphids and remarks on the origin of the therian scapula.

The development of the scapula was studied in embryonic and postnatal specimens of Monodelphis domestica and perinatal specimens of Philander opossum, Caluromys philander, and Sminthopsis virginiae using histological sections and 3D reconstructions. Additionally, macerated skeletons of postnatal M. domestica were examined. This study focused on the detachment of the scapulocoracoid from the sternum and on the acquisition of a supraspinous fossa, a supraspinatus muscle, and a scapular spine, all these events associated with the origin of the therian shoulder girdle. In none of the specimens is there a continuity of the cartilaginous scapulocoracoid with the sternum, even though the structures are in close proximity, especially in S. virginiae. At birth, the first rib laterally presents a pronounced boss that probably contacts the humerus during certain movements. Only the acromial portion of the scapular spine, which originates from the anterior margin of the scapular blade, is preformed in cartilage. The other portion is formed by appositional bone ("Zuwachsknochen"), which expands from the perichondral ossification of the scapula into an intermuscular aponeurosis between the supra- and infraspinous muscles. This intermuscular aponeurosis inserts more or less in the middle of the lateral surface of the developing scapula. Thus, the floor of the supraspinous fossa is present from the beginning of scapular development, simultaneously with the infraspinous fossa. The homology of the therian spine with the anterior border of the sauropsid and monotreme scapula is questioned. We consider the dorsal portion (as opposed to the ventral or acromial portion) of the scapular spine a neomorphic structure of therian mammals.

Animals↗
PubMed2007

Incidence and survival of childhood Langerhans cell histiocytosis in Northwest England from 1954 to 1998.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare proliferative disorder of pathological Langerhans cells, for which the aetiology and pathogenesis remain largely unknown. PROCEDURE: Information on the 101 children with LCH registered with the population-based Manchester Children's Tumour Registry (MCTR) between 1954 and 1998 was extracted from the records of the MCTR. This included age, sex, date of diagnosis, systems affected at diagnosis and follow-up. RESULTS: The overall incidence rate for LCH was 2.6 cases per million child years. In those under 1 year of age the incidence rate was 9.0 cases per million child years, compared to 0.7 cases per million in those aged 10-14 years (P < 0.0001 for age trend). There was no evidence of seasonal variation in presentation by month of birth or first symptom. Bone was the most common site of disease involvement (67% of cases), followed by skin (37%) and soft tissue (22%). The overall survival rate has improved over time, from 57% in 1954-1968 to 74% in 1985-1998. Ninety percent of deaths were due to disease progression, the remainder were due to complications of intensive therapy. The site of LCH lesions and extent of disease present at diagnosis strongly predicted survival outcome. Patients with initial liver involvement had a 5-year survival rate of 25% compared with 93% for those with bone lesions alone at diagnosis. CONCLUSIONS: Incidence rates varied significantly by age at diagnosis, and have been stable over time. Survival has improved considerably over time, but varies strongly by age and systems affected at diagnosis.

Adolescent↗
PubMed2005

Tutorial in biostatistics: spline smoothing with linear mixed models.

The semi-parametric regression achieved via penalized spline smoothing can be expressed in a linear mixed models framework. This allows such models to be fitted using standard mixed models software routines with which many biostatisticians are familiar. Moreover, the analysis of complex correlated data structures that are a hallmark of biostatistics, and which are typically analysed using mixed models, can now incorporate directly smoothing of the relationship between an outcome and covariates. In this paper we provide an introduction to both linear mixed models and penalized spline smoothing, and describe the connection between the two. This is illustrated with three examples, the first using birth data from the U.K., the second relating mammographic density to age in a study of female twin-pairs and the third modelling the relationship between age and bronchial hyperresponsiveness in families. The models are fitted in R (a clone of S-plus) and using Markov chain Monte Carlo (MCMC) implemented in the package WinBUGS.

Adolescent↗
PubMed1993

A computer program for estimating individualized probabilities of breast cancer.

A computer program is presented for estimating the absolute risk of developing breast cancer over a specified age interval for women with combinations of five risk factors, namely age at menarche, age at first live birth, family history of breast cancer, number of previous breast biopsies, and presence of atypical hyperplasia in biopsy specimens. Statistical methods have been developed and applied to data from the Breast Cancer Detection and Demonstration Project to obtain (i) point estimates of absolute risk by combining relative risk estimates from case-control data and estimated composite incidence rates from cohort data, and (ii) confidence intervals by using implicit delta-method arguments. The program is interactive and easy to use and is therefore well suited to assist in medical counseling. For instance, women with high estimated risk might be advised to undergo a program of frequent surveillance with mammography. An executable version for IBM-compatible PCs is available from the author upon submission of a PC diskette formatted with MS-DOS.

Adult↗
PubMed1999

Intrauterine lead exposure and preterm birth.

The objective of this study was to determine the risk of preterm birth in relation to umbilical cord blood lead levels (UCL) among primiparous and multiparous women. A case-cohort study was performed in Mexico City during 1995. A total of 459 full-term births was compared with 161 preterm births (before 37 gestational weeks). Mothers were interviewed before the delivery about their reproductive histories and other related factors of preterm birth. Lead was determined by atomic absorption spectrophotometry. Lead levels were higher in primiparous women who had a preterm birth than in primiparous women with a full-term birth (9.77+/-2.0 microgram/dl vs 8.24+/-2.15 microgram/dl); this difference was marginally significant. After adjusting for other known preterm birth risk factors, the frequency of preterm birth was almost three times higher among women who had UCL levels greater or equal to 5.1 microgram/dl compared to those who had UCL levels lower than 5.1 microgram/dl. This difference was not observed among multiparous women. Our results suggest that intrauterine lead exposure may be associated with preterm birth in first deliveries but not in subsequent ones.

Adolescent↗
PubMed1994

Gene expression of progesterone receptor isoforms in the rat brain.

Progesterone receptors (PRs) are known to exist in two forms: a larger molecular, form B, and a smaller one, form A. Rat PR cDNA corresponding to the region around the translation-initiation site (ATGB) of the putative PR form B mRNA was cloned, together with cloning of steroid-binding domain of the PR forms A and B. An imperfect "estrogen responsive element," GGTCG*** TGACT, was located around ATGB of the rat PR cDNA. The distribution of PR mRNA-containing neurons was mapped in the female adult rat brain by in situ hybridization, which was largely in agreement with that of PR proteins. Differential intracerebral distribution of the mRNAs, measured by the quantitative RT-PCR Southern blotting assay, was found between the total (A+B) and form B mRNA levels, indicating possible distinct mechanisms responsible for regulation of the expression of the PR mRNAs. A region-specific and stage-related gene expression of form B seems predominantly to be "turned on" first around birth, followed by that of form A around Days 8-12. The postnatal developmental pattern of PR form B mRNA in the cerebral cortex resembled that of the PR proteins. Noninducibility of the cortical PR by estrogen might be ascribable to the predominance of form B mRNA, which was reported to have little or no estrogen inducibility. A missmatch existed between PR from A and its mRNA levels, suggesting some impairment of the synthesis of form A. Thyroid hormone may be a regulator of gene expression of the receptor in the developing cortex.

Amino Acid Sequence↗
PubMed2000

Determinants of infant feeding method in relation to risk factors for breast cancer.

BACKGROUND: Breastfeeding is considered to be an important factor for maternal and children's health. However, the epidemiological findings related to the effect of breastfeeding on women's health, especially with respect to breast cancer development, are inconsistent. Determinants of infant feeding method may contribute to the inconsistency. METHODS: A total of 24,769 women aged 40-64 in Miyagi Prefecture, Japan, responded to a self-administered questionnaire survey in 1990. Using the data obtained from 22,085 parous women, we calculated odds ratios (ORs) for the choice of "breastfeeding only" during reproductive period. RESULTS: Late age at menarche (> or = 16 years, OR = 1.57) and high body mass index (BMI) at 20 years of age (> or = 24, OR = 1.31) were associated with the choice of breastfeeding only. Late age at birth of first child (> or = 28 years, OR = 0.29), history of breast cancer in mother (OR = 0.68), and high educational level (more than a high school education, OR = 0.53) reduced the possibility of choosing breastfeeding only. CONCLUSION: The results indicate that the choice of infant feeding method is associated with several breast cancer risk factors. Based on this finding, we should construct appropriate breast cancer risk models for parous women and investigate the changes in the effects of breastfeeding and other breast cancer risk factors among these risk models. Especially in a risk model controlling for breastfeeding, the effects of other breast cancer risk factors should be reevaluated. Through comparisons among different risk models, we may find the best-fitted risk model and identify the true effect of breastfeeding.

Adolescent↗
PubMed1995

Spontaneous abortion and risk of fatal breast cancer in a prospective cohort of United States women.

Controversy exists over the possible relationship between induced and spontaneous abortion and risk of breast cancer. Thus, the association of fatal breast cancer and spontaneous abortion was examined in a large prospective study of United States adult women. After seven years of follow-up, 1,247 cases of fatal breast cancer were observed among 579,274 women who were cancer-free at interview in 1982 and who provided complete reproductive histories. Results from Cox proportional hazards models, adjusted for other risk factors, showed no association between a history of spontaneous abortion and risk of fatal breast cancer (rate ratio [RR] = 0.89, 95 percent confidence interval [CI] = 0.78-1.02). The RR did not increase with increasing numbers of abortions. Parous women who had a spontaneous abortion before their first term birth were not at increased risk compared with parous women with no history of spontaneous abortion (RR = 0.76, CI = 0.54-1.05). Women whose only pregnancy ended in a spontaneous abortion were not at increased risk compared with women who were never pregnant (RR = 0.61, CI = 0.27-1.38) or whose only pregnancy ended in a livebirth (RR = 0.72, CI = 0.32-1.65). These findings do not support an association between spontaneous abortion and fatal breast cancer.

Abortion, Spontaneous↗
PubMed1981

Correlative ontogenetic development of catecholamine- and LHRH-containing nerve endings in the median eminence of the rat.

The ontogenetic development of catecholamine (CA)- and LHRH-containing nerve endings in the median eminence of the rat was investigated by combining fluorescence histochemistry and immunohistochemistry in the same tissue section. LHRH-terminals appeared earlier than CA-terminals and were already detectable in the lateral part of the external layer of the central ME on the first day after birth. CA-nerve endings were first seen in a corresponding region of the ME on the seventh postnatal day. At this stage both types of terminals showed the earliest manifestation of a correlative pattern of their distribution. Subsequently the development of both types of nerve endings proceeded rapidly, and at 14 days their distribution pattern corresponded to that in adult animals. The authors conclude that at this stage the CA-neurons play a constant and significant role in the release of LHRH into the portal capillaries. The correlation between both types of nerve endings and the ontogenetic development of the capillary plexuses of the hypophysial portal system is discussed.

Age Factors↗
PubMed1989

Myelin breakdown in the posterior funiculus of the kitten after dorsal rhizotomy. A qualitative and quantitative light and electron microscopic study.

Morphological aspects of myelin breakdown in the posterior funiculus during Wallerian degeneration were studied in kittens subjected to lumbosacral dorsal rhizotomies 6-8 days after birth. The first sign of myelin breakdown was characterized by swollen or shrunken nerve fibers. Shortly thereafter there was an increased occurrence of collapsed myelin sheaths and later of rounded myelin bodies. Myelin was clearly seen in microglial cells. Correlative observations on Marchi-stained material indicted the simultaneous and frequent appearance of Marchi-positive bodies (MPB:s) and myelin bodies. Due to the rapidity of the degeneration process in the kitten, the increase in the occurrence of Marchi-positive granules (MPG:s) seemed to start concomitantly with increased occurrence of MPB:s. However, the frequent occurrence of MPG:s outlasted that for MPB:s. The findings indicate that the MPB:s may be the counterpart to myelin bodies and the MPG:s to lipid droplets. Microglial cells may be responsible for the primary uptake of degenerating myelin and the subsequent transformation of myelin bodies to lipid droplets. The much faster breakdown of myelin and elimination of lipid material in the degenerating posterior funiculus of the kitten, as compared to the adult, seemed to be due not only to the lower myelin content in the kitten, but also to a higher density of microglial and a greater efficiency in the myelin breakdown process in the degenerating posterior funiculus of the kitten.

Animals↗
PubMed1990

[Spatial mobility on reaching adult age].

"Starting with longitudinal data on two cohorts of women living in the Alpes-Maritimes [France] in 1982 (a sample of 1,500 women in total) we try to establish the role of the spatial distribution of opportunities at a number of key stages in the life cycle: marriage, birth of first child, making professional use of qualifications, confrontation of a situation of professional risk and professional mobility during the years immediately following the completion of studies. The underlying hypothesis is that control of social location often depends on the control of spatial location." (SUMMARY IN ENG)

Adult↗
PubMed1987

Argininosuccinic aciduria: long-term treatment with arginine.

The presentation and 2 year treatment of a patient with argininosuccinic aciduria is reported. Erythrocyte argininosuccinate lyase activity was less than 2% of normal. Long-term management included protein restriction and arginine dietary supplementation. The child experienced three episodes of hyperammonaemia (greater than 100 microns), the first at birth, the second at 6.5 months and the third at 16 months. Neurological development deteriorated between 14 and 24 months. Hepatomegaly and biochemical hepatitis, a feature of this condition, was accompanied by enlarged mitochondria with tubular paracrystalline inclusions not previously recognized in this disorder.

Amino Acid Metabolism, Inborn Errors↗
PubMedDate not supplied

Breast feeding patterns in an urban resettlement colony of Delhi.

Studies on duration and patterns of breast feeding based on recall may lead to a bias about the exact feeding status. The present study was designed to overcome this bias using the 'current status analysis method'. Mothers of 650 infants from 0 to 12 months of age attending a Health Centre were interviewed about the current feeding patterns of the infants and other socioeconomic variables. Month-wise prevalence of feeding patterns was determined. It was observed that breast feeding was maintained at a high level (more than 90%) throughout infancy while exclusive breast feeding showed a rapid decline. At 1 month, 74% and at 4 months, 46% of infants were exclusively breast-fed. The median duration of exclusive breast feeding was 3.83 months. Mothers with lesser education and lower family income were more likely to exclusively breast feed (p < 0.05). The time interval between birth and first breast feed was 24-48 hours in most (48.9%) of the infants. Majority (76.9%) of the infants received pre-lacteal feeds. Hospital-born infants received their first feed earlier and were less likely to receive pre-lacteal feeds as compared to those born at home (p < 0.001). Thus, the practice of exclusive breast feeding has to be promoted amongst pregnant and lactating mothers by health personnel. Also knowledge regarding infant feeding has to be imparted in schools and colleges.

Breast Feeding↗
PubMed2001

Limited association between a catechol-O-methyltransferase (COMT) polymorphism and breast cancer risk in Japan.

BACKGROUND: Catechol-O-methyltransferase (COMT) inactivates the estradiol metabolites, 2-hydroxy estradiol and 4-hydroxy estradiol. To date, three studies in Caucasians and one study in Chinese have been conducted to determine the association with breast cancer risk of a functional polymorphism (G-to-A, Val158Met) of this enzyme, but the results were inconsistent. In order to examine the impact of this polymorphism on breast cancer risk in Japan, a case-control study was conducted, at Aichi Cancer Center Hospital. METHODS: The cases were 150 patients with histologically confirmed breast cancer who had been diagnosed within 4 years before enrollment at this hospital. The controls were 165 non-cancer patients, mainly from the gastroenterology and breast surgery clinics at the hospital. COMT-H (Val) is the wild-type allele, with high enzyme activity, while the COMT-L (Met) allele has low activity. Genotyping was conducted by a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method. RESULTS: The allele frequency of COMT-L was 36.0% for cases and 33.0% for controls. Age-adjusted odds ratios relative to the COMT-HH genotype were 1.46 (95% confidence interval [CI], 0.90-2.36) for COMT-HL, and 0.99 (95% CI, 0.49-2.02) for the COMT-LL genotype. Significant odds ratios were not observed for any subgroup stratified by menopausal status, age at menarche, age at birth of first child, body mass index, and breast cancer history of mother and/or sister(s). CONCLUSION: The present study suggested that any association of the COMT polymorphism with breast cancer risk is limited in Japanese.

Adult↗