Estimated risk for altered fetal growth resulting from exposure to fine particles during pregnancy: an epidemiologic prospective cohort study in Poland.
(25/1302)
The purpose of this study was to estimate exposure of pregnant women in Poland to fine particulate matter [less than or equal to 2.5 microm in diameter (PM 2.5)] and to assess its effect on the birth outcomes. The cohort consisted of 362 pregnant women who gave birth between 34 and 43 weeks of gestation. The enrollment included only nonsmoking women with singleton pregnancies, 18-35 years of age, who were free from chronic diseases such as diabetes and hypertension. PM 2.5 was measured by personal air monitoring over 48 hr during the second trimester of pregnancy. All assessed birth effects were adjusted in multiple linear regression models for potential confounding factors such as the size of mother (maternal height, prepregnancy weight), parity, sex of child, gestational age, season of birth, and self-reported environmental tobacco smoke (ETS). The regression model explained 35% of the variability in birth weight (beta = -200.8, p = 0.03), and both regression coefficients for PM 2.5 and birth length (beta = -1.44, p = 0.01) and head circumference (HC; beta = -0.73, p = 0.02) were significant as well. In all regression models, the effect of ETS was insignificant. Predicted reduction in birth weight at an increase of exposure from 10 to 50 microg/m3 was 140.3 g. The corresponding predicted reduction of birth length would be 1.0 cm, and of HC, 0.5 cm. The study provides new and convincing epidemiologic evidence that high personal exposure to fine particles is associated with adverse effects on the developing fetus. These results indicate the need to reduce ambient fine particulate concentrations. However, further research should establish possible biologic mechanisms explaining the observed relationship. (+info)
Uterine and placental factors regulating conceptus growth in domestic animals.
(26/1302)
All mammalian uteri contain endometrial glands that synthesize or transport and secrete substances essential for survival and development of the conceptus (embryo/fetus and associated extraembryonic membranes). The ovine uterine gland knockout ewe model supports a primary role for endometrial glands and, by default, their secretions as essential for conceptus survival and development during the peri-implantation period of pregnancy. Endometrial adenogenesis, the process whereby glands develop in the uterus, is primarily a postnatal event in domestic and laboratory animals, as well as in humans. Endometrial adenogenesis involves differentiation and budding of glandular epithelium from lumenal epithelium, followed by invagination and extensive tubular coiling and branching morphogenesis throughout uterine stroma to the myometrium. In sheep, pituitary prolactin acting on prolactin receptors expressed by uterine glandular epithelium regulates endometrial adenogenesis. In contrast, expression and functional activation of estrogen receptor alpha in the uterus is a primary regulator of endometrial adenogenesis in the pig. In adult sheep and pigs, extensive endometrial gland hyperplasia and hypertrophy occur during gestation, presumably to provide increasing histotrophic support for conceptus growth and development. A servomechanism has been proposed in sheep and pigs to regulate endometrial gland development and differentiated function during pregnancy that involves sequential actions of ovarian steroid hormones, pregnancy recognition signals, and lactogenic hormones from the pituitary and/or placenta. The fact that disruption of uterine development during critical organizational periods can alter the functional capacity and embryotrophic potential of the adult uterus reinforces the importance of understanding uterine developmental biology. Defects in endometrial gland morphogenesis during uterine growth and development may cause the unexplained, high rates of peri-implantation embryonic loss in domestic animals and humans. Knowledge of the basic mechanisms regulating uterine development is expected to suggest means to increase uterine capacity, litter size, and neonatal survival, as well as ameliorate certain types of infertility. (+info)
Development of fetuses from in vitro-produced and cloned bovine embryos.
(27/1302)
The establishment of in vitro fertilization and culture systems for mammalian embryos has facilitated the application of embryo technologies in research, industry, and clinical settings. Furthermore, the advent of cloning by nuclear transfer has significantly enhanced the potential for genetic modification of livestock. Based on studies in cattle, sheep, and mice, it has become apparent that embryos produced using these systems can differ in morphology and developmental potential compared with embryos produced in vivo. Referred to as "large offspring syndrome," these abnormalities in the development of fetuses, placentas, and offspring are particularly evident following transfer of cloned embryos, but they also occur in pregnancies from embryos produced using in vitro culture alone. The objective of this review is to examine the effects of in vitro production and cloning on bovine embryo and fetal development. Literature pertaining to preimplantation embryo, conceptus, and fetal development, as well as gene expression occurring at each of these three stages, is reviewed. Physiologic and genetic mechanisms that contribute to large offspring syndrome also are discussed. (+info)
Effects of short-term early gestational exposure to endophyte-infected tall fescue diets on plasma 3,4-dihydroxyphenyl acetic acid and fetal development in mares.
(28/1302)
Consumption of wild-type (toxic) endophyte-infected tall fescue (E+) by horses during late gestation is known to adversely affect pregnancy outcome; however, little is known of the potential disruptive consequences of E+ consumption by mares during the critical phases of placentation and fetal development in early pregnancy. The objective of this study was to evaluate the detrimental effects of feeding E+ to mares during early gestation. Mares (n = 12) paired by stage of gestation (d 65 to 100) were assigned to diets (six per diet) consisting of endophyte-free (E-) or E+ tall fescue seed (50% E- or E+ tall fescue seed, 45% sweet feed, and 10% molasses fed at 1.0% of BW/d). Mares also had ad libitum access to E+ or E- annual ryegrass hay, and were fed diets for 10 d. Following removal from the tall fescue diet on d 11, mares were placed on common bermudagrass pasture and monitored until d 21. Morning and evening rectal temperatures were recorded and daily blood samples were collected for progesterone and prolactin (PRL) analyses, whereas samples for 3,4-dihydroxyphenyl acetic acid (a catecholamine metabolite) analysis were collected on alternate days. For clinical chemistry analysis, blood samples were collected on d 0, 5, 10 and 21. Daily urine samples were collected for ergot alkaloid analysis, and ultrasonography was performed for presence of echogenic material in fetal fluids. Rectal temperatures (E+ 37.76+/-0.03; E- 37.84+/-0.03 degrees C) and serum PRL concentrations (E+ 14.06< or =0.76; E- 12.11+/-0.76 ng/mL) did not differ (P = 0.96) between treatments. Measuring the change in basal serum concentration from d 0 over time, progesterone concentrations did not differ (-0.64 +/-1.49 and -0.55+/-1.47 ng/mL for E+ and E- mares, respectively). There was no negative pregnancy outcome, and ultrasonography indicated no increase in echogenic material in fetal fluids. Plasma 3,4-dihydroxyphenyl acetic acid concentrations decreased (P < 0.05) in E+ compared with E- mares (2.1+/-0.14 and 4.4+/0.43 ng/mL, respectively). Urinary ergot alkaloid concentration was greater (P < 0.01) in mares consuming E+ compared with E- (532.12+/- 52.51 and 13.36+/-2.67 ng/mg of creatinine, respectively). Although no fetal loss was observed during the current study, elevated concentrations of urinary ergot alkaloid were consistent with depressed endogenous catecholamine activity, suggestive of an endocrine disruptive effect of hypothalamic origin. (+info)
Effect of dietary restriction, pregnancy, and fetal type on intestinal cellularity and vascularity in Columbia and Romanov ewes.
(29/1302)
The objectives of this study were to evaluate intestinal cellularity and vascularity in mature ewes in response to dietary restriction and pregnancy status and to quantify the response of these variables to increased nutrient demand of fetal growth. In Exp. 1, 28 mature Dorset x crossbred white-faced ewes (61.6+/-1.8 kg initial BW) were fed a pelleted, forage-based diet. Treatments were arranged in a 2 x 3 factorial, with dietary restriction (60% restriction vs. 100% maintenance for respective states of pregnancy) and pregnancy status (nonpregnant, NP; d 90 and 130) as main effects. Dietary treatments were initiated on d 50 of gestation and remained at 60 or 100% maintenance throughout the experiment. Nonpregnant ewes were fed dietary treatments for 40 d. In Exp. 2, four Romanov ewes were naturally serviced (Romanov fetus and Romanov dam; R/R); two Romanov embryos per recipient were transferred to four Columbia recipients (Romanov fetus and Columbia recipient; R/C), and three Columbia ewes were naturally serviced (Columbia fetus and Columbia dam; C/C). In Exp. 1, dietary restriction and pregnancy status interacted with regard to maternal jejunal DNA concentration (P < 0.01), with restricted ewes having a greater DNA concentration (mg/g; fresh basis) at d 130. Vascularity (percentage of total tissue area) in the jejunum was increased (P < 0.06) as a result of dietary restriction and pregnancy status. Total microvascular volume ofjejunal tissue was not altered by dietary restriction and increased (P < 0.01) at d 130 of pregnancy. In Exp. 2, R/R ewes had less (P < 0.09) DNA (g) in the jejunum compared with R/C and C/C ewes. Jejunal vascularity (%) was increased (P < 0.05) in R/R ewes compared with R/C or C/C ewes, whereas total jejunal microvascular volume remained unchanged. These data demonstrate intestinal vascular density responds to changes in diet and physiological state. In addition, pregnancy increased total jejunal microvascular volume. (+info)
Expression, localization, and function of the carnitine transporter octn2 (slc22a5) in human placenta.
(30/1302)
L-carnitine is assumed to play an important role in fetal development, and there is evidence that carnitine is transported across the placenta. The protein involved in this transfer, however, has not been identified on a molecular level. We therefore characterized localization and function of the carnitine transporter OCTN2 in human placenta. Significant expression of OCTN2 mRNA was detected in human placenta applying real-time polymerase chain reaction technology. Confocal immunofluorescence microscopy using an antibody directed against the carboxy terminus of OCTN2 protein revealed that it is predominantly expressed in the apical membrane of syncytiotrophoblasts. This was confirmed by the costaining of organic anion-transporting polypeptide B and MRP2, which are known to be expressed mainly in the basal and apical syncytiotrophoblasts membrane, respectively. To further support this finding, we performed transport studies using basal and apical placenta membrane vesicles. We could demonstrate that the carnitine uptake into the apical vesicles was about eight times higher compared with the basal ones. Moreover, this uptake was sodium- and pH-dependent with an apparent K(m) value of 21 muM and inhibited by verapamil, which is in line with published data for recombinant OCTN2. Finally, experiments using trophoblasts in cell culture revealed that expression of OCTN2 paralleled human choriogonadotropin production and thus is modulated by cellular differentiation. In summary, we show expression and function of OCTN2 in human placenta. Moreover, several lines of evidence indicate that OCTN2 is localized in the apical membrane of syncytiotrophoblasts, thereby suggesting a major role in the uptake of carnitine during fetal development. (+info)
Should diagnostic testicular sperm retrieval followed by cryopreservation for later ICSI be the procedure of choice for all patients with non-obstructive azoospermia?
(31/1302)
BACKGROUND: This was a retrospective study to determine if diagnostic testicular biopsy followed by cryopreservation should be the procedure of choice for all patients with testicular failure. METHODS: The first part of the study analysed 97 ICSI cycles scheduled with frozen-thawed testicular sperm for 69 non-obstructive azoospermia (NOA) patients. The second part focused on a subgroup of 32 patients who underwent 42 ICSI cycles with frozen and 44 cycles with fresh testicular sperm. Sperm characteristics, fertilization, embryo quality, pregnancy and implantation rates were evaluated. RESULTS: Part I: The average time needed to find sperm was 113 min per cycle and 17 min per individual sperm. Fertilization rate, embryo transfer rate, ongoing pregnancy and implantation rates were 58.4%, 83%, 20.8% and 11.3%, respectively. Part II: The search time per sperm was higher (P=0.016) in frozen (18 min) than in fresh suspensions (13 min). A higher embryo transfer rate was observed in fresh cycles than in frozen cycles (93.2% vs 76.2%, P=0.028). Fertilization, ongoing pregnancy and implantation rates were comparable for the two groups. CONCLUSIONS: Even in a programme with low-restrictive criteria for patient allocation and for sperm cryopreservation, diagnostic testicular biopsy followed by cryopreservation can be the procedure of choice for patients with testicular failure. (+info)
The gubernaculum in testicular descent and cryptorchidism.
(32/1302)
The gubernaculum plays an essential role in the complex mechanism of testicular descent and inguinal hernia closure. Understanding this complex developmental process is gradually allowing us insight into how to regulate normal descent and also treat maldescended testes. (+info)