1,720,990 research outputs found
Miscarriage diagnosis and gestational age estimation in the early first trimester of pregnancy: transvaginal versus transabdominal sonography
No full textA comparison is made between 290 patients examined using transabdominal sonography and 308 patients examined using transvaginal sonography. Patients with suboptimal menstrual histories and threatened miscarriages were excluded from these two groups of patients. The transabdominal and transvaginal sonography examinations were carried out while the patient's bladder was empty, so that there was no delay between the clinical and sonographic examinations. In this way there was no patient discomfort from a full bladder. In normal pregnancies after 42 days of amenorrhea, the percentage visualization rates of the chorionic sac, of the embryo with heart activity and of the yolk sac were measured. There were no significant differences between the two groups. The two techniques were able to provide a reliable diagnosis of miscarriage on embryos >or= 4 mm or with chorionic sacs >or= 10 mm mean diameter. However, before 42 days of gestation, transvaginal sonography was better than transabdominal sonography at diagnosing miscarriage. The percentage of anembryonic pregnancies was higher in the transabdominal sonography group (21%) than in the transvaginal sonography group (7%), despite similar gestational ages at the time of a positive diagnosis. Thus, a transabdominal scan can be used after 42 days and borderline cases can be referred for transvaginal sonography for confirmation
Intra-amniotic pressure is not affected by amniocentesis between 13 and 18 weeks of gestation
No full textChanges in amniotic fluid pressure before and after amniocentesis fell within the range of +/- 5 mmHg, except when uterine contractions were present. Intra-amniotic pressure is not affected by amniocentesis between 13 and 18 weeks of gestation. Amniotic fluid pressure was recorded in 82 pregnancies of patients undergoing genetic amniocentesis to determine whether sampling of amniotic fluid between 13 and 18 weeks changed intra-amniotic pressure. Pressures were recorded through a needle and saline filled catheter with a zero-level at the needle tip. Amniotic fluid pressure was unrelated to gestational age (P = 0.962) during the weeks we performed our measurements. Fluid samples of 12.6% of the total volume in a group of early genetic amniocentesis (n = 65) and of 7.5% of the total volume in a group of late genetic amniocentesis (n = 17) did not change significantly amniotic fluid pressure values. An increase in pressure of more than 5 mmHg only occurred in cases where uterine contractions were present. Other than these cases, all pressure change values fell within the range of +/- 5 mmHg. No difference in pregnancy outcome were present within the two groups. An argument for a standard method for stationing pressure is presented
Predictability of duration and severity of congenital hydronephrosis as a cause of smooth muscle deterioration in pyelo-ureteral junction obstruction
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Brain vulnerability and its modulation
No full textClinical and experimental studies revealed that the injured brain is highly vulnerable to a subsequent insult. Surfery of the literature pertinent to clinical and experimental traumatic brain injury (TBI) is made. Increased vulnerability of the traumatically injured brain to an additional sub lethal ischemic, hypoxic, excitotoxic, or mechanical insult has been clearly demonstrated. Compared to traumatic brain injury alone, the double insult paradigm dramatically increases the brain damage. Brain vulnerability following TBI can be explained by a reduced ability to compensate for a reduction of cerebral blood flow (CBF) and oxygen (O(2)) delivery to the brain or inability to meet an increased metabolic demand. In addition, there is a specific increased sensitivity to delayed insults induced by the first injury. Potential mechanisms of the increased sensitivity to a second insult might be related to post-traumatic gene expression alterations leading to changes in neurotransmitters release, density of receptors and reduced thresholds for activation of pathways leading to delayed cell death. The brain is vulnerable to repetitive injuries. Derangements of compensatory mechanisms are responsible, in part, for this vulnerability. Additional work is needed to better understand the molecular pathways leading to secondary damage and to find novel therapeutic strategies to modulate the brain response to TBI
First trimester placental markers in oocyte donation pregnancies
No full textIntroduction This study investigates the hypothesis that placenta works differently in oocyte donation (OD) compared to spontaneous pregnancies. To verify this hypothesis we examine the first trimester maternal serum levels of free β-hCG and pregnancy-associated plasma protein-A (PAPP-A). Then we evaluated for potential differences of Down syndrome screening between OD pregnancies, in vitro fertilization/intracytoplasmic sperm injection pregnancies with autologous oocytes (IVF/ICSI) and spontaneous pregnancies. Methods We analyze 13624 spontaneously conceived pregnancies (Controls), 171 oocyte donation pregnancies (OD IVF/ICSI) and 76 IVF pregnancies with autologous oocytes (Autologous IVF/ICSI). Furthermore, we collect a cohort of 802 spontaneously conceived age-matched pregnancies, in order to evaluate how older uteri contribute to explain the changes in markers concentrations (Age-matched controls We compare the multiples of the median (MoM) of free β-hCG and PAPP-A and nuchal translucency. Results Free β-hCG levels are significantly higher both in OD IVF/ICSI pregnancies (1.44 ± 1.06 MoM) and Autologous IVF/ICSI (1.48 ± 1.02 MoM) compared to Controls (1.15 ± 0.84 MoM; p < 0.05) and Age-matched Controls (1.18 ± 0.98 MoM; p < 0.05). PAPP-A levels do not significantly differ among the four groups. Significantly lower nuchal translucency is detected in Controls (1.41 ± 0.36 mm) compared to OD IVF/ICSI (1.46 ± 0.44 mm; p < 0.05), in Autologous IVF/ICSI (1.51 ± 0.34 mm; p < 0.05) and Age-matched Controls (1.44 ± 0.42 mm; p < 0.05). Discussion Oocyte donation pregnancies (OD IVF/ICSI) are significantly related to altered maternal serum placenta marker levels. These alterations might be due to the IVF technique
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