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991.
992.
Preimplantation genetic diagnosis of chromosome balance in embryos from a patient with a balanced reciprocal translocation 总被引:4,自引:1,他引:3
Duplications or deletions are present in a high percentage of the gametes
produced by individuals carrying balanced translocations. Preimplantation
genetic diagnosis was used to examine chromosome balance in embryos from a
patient having a reciprocal translocation within the short arms of
chromosomes 5 and 8 (46,XX,t(5;8)(p13;p23)). This woman has two sisters
with the translocation unbalanced, resulting in a partial trisomy for
chromosome 5 and partial monosomy for chromosome 8 (46,XX,-8,
+der(8)t(5;8)(p13;p23)) with associated mental retardation and physical
abnormalities. The patient and her husband desired to have children without
the abnormal chromosome balance and wished to reduce the likelihood of
spontaneous abortion or need for therapeutic abortion. Fluorescence in-situ
hybridization (FISH) probes for the alpha-satellite region of chromosome 8
and for a region on the short arm of chromosome 5 (5p15.2) were tested
initially on lymphocytes from the patient and her sisters. The
hybridization signal for chromosome 5 was detected in the expected two
copies for the patient and three copies for the sisters in 87% of the
cells. Two hybridization signals for chromosome 8 were detected in 96% of
the cells from all individuals. Additional probe testing was done using
blastomeres from polyspermic embryos. The couple then proceeded with a
stimulated in- vitro fertilization (IVF) cycle and biopsies were done on 13
embryos at the 7-10-cell stage using a method of zona drilling and fluid
displacement. Diagnosis was possible on at least one blastomere for nine
embryos. Three embryos had nuclei with three hybridization signals for
chromosome 5, three had fewer than two signals for one or both chromosomes,
one was mosaic, and two had two signals for each chromosome. The latter
were transferred to the patient, but pregnancy was not achieved. The
results demonstrate that preimplantation genetic diagnosis for patients
with reciprocal translocations can be used to identify embryos having
normal chromosome balance. The potential advantages and limitations of this
approach are discussed.
相似文献
993.
994.
Background: Regional Trauma Centre in the northern India receives the mortal remains of all fallen soldiers for embalming. Non enemy action deaths during counter insurgency operations (CI Ops) were analysed for planning preventive measures. 相似文献
995.
Edmond Zahedi Kalaivani Chellappan Mohd Alauddin Mohd Ali Harwant Singh 《Cardiovascular Engineering》2007,7(4):172-181
Ageing is one of the main contributing factors towards increasing arterial stiffness, leading to changes in peripheral pulses
propagation. Therefore the characteristics of the photoplethysmogram (PPG) pulse, especially the rising edge and peak position,
are greatly affected. In this study, the PPG pulse rising edge and corresponding peak position have been investigated non-invasively
in human subjects as a function of age. Fifteen healthy subjects were selected and grouped in five age intervals, from 20
to 59 years, based on their comparable systolic-diastolic blood pressure and PPG amplitude. As expected, the peripheral pulse
shows a steep rise and early peak in younger subjects. With age, the slope becomes blunted and in older subjects, the rise
is very gradual and the pulse peak appears much later. Qualitative results were further verified by a modified 10-element
Windkessel model to quantify the lumped parameter changes with ageing. This verification highlighted some specific changes
in vascular parameters with aging. The rising edge could be considered as one parameter in determining the age-dependent vascular
state. 相似文献
996.
997.
使用比较分子场分析法(comparativemolecularfieldanalysis,CoMFA)[1]建立了一个维甲类化合物抗致癌活性的三维构效关系(3D-QSAR)模型,用交叉验证法(cros-validation)、和非交叉验证方法(non-cros-validation)分别验证和建立的分子场模型,高的交叉验证回归系数(R2CV=0.905)说明系列化合物分子周围空间场和静电场分布的差异与其生物活性差异间存在良好的相关性。用这个模型预测在建立模型时没有包括进去的三个化合物的活性,预测值接近实验值,提示该模型有较好的活性预测能力,可用来指导设计新的高活性维甲分子。化合物分子的最低能量构象未必是其活性构象。用得到的化合物最低能量构象进行CoMFA研究,其交叉验证系数较低(R2CV=0.420),不具有统计学意义。但将部分分子的单键微弱旋转,构象能变化控制在2kcal·mol-1之内,其它分子采取最低能量构象,则得到高的交叉验证系数。叠合的配体分子场模拟了配体分子周围的作用环境,反映受体结合部位与配体之间存在相互作用的基团和(或)原子的空间和静电性质,分子场模型在作为预测活性模板的同时也在一定程度上映射出受体结合部位的三维拓扑形状和理化特性。 相似文献
998.
Patrina H.Y. Caldwell BMed FRACP Jonathan C. Craig MBChB MM DCH FRACP PhD Phyllis N. Butow BA MPH MClinPsych PhD 《The Journal of pediatrics》2004,144(1):140-141
999.
DIURNAL EFFECTS OF FLUOXETINE AND NALOXONE ON THE HUMAN HYPOTHALAMIC-PITUITARY-ADRENAL AXIS 总被引:1,自引:0,他引:1
DJ Torpy JE Grice GI Hockings MM Walters GV Crosbie RV Jackson 《Clinical and experimental pharmacology & physiology》1997,24(6):421-423
1. Central serotonergic pathways are hypothesized to be involved in the stimulation of hypothalamic adrenocorticotropic hormone (ACTH) secretagogue release by both circadian- and stress-induced mechanisms. We aimed to investigate this hypothesis by measuring the effect of the highly specific serotonin re-uptake inhibitor fluoxetine (FX) on ACTH and Cortisol release in the morning and in the afternoon in humans, both by itself and in combination with the opioid antagonist naloxone (Nal). Naloxone causes ACTH release in humans by removing an endogenous inhibitory opioid tone on central noradrenergic pathways stimulatory to hypothalamic corticotropin-releasing hormone (CRH) secretion. Serotonergic agents may act directly or indirectly through these central noradrenergic pathways and, if so, would be expected to be additive to or synergistic with Nal in causing ACTH and Cortisol release. 2. Oral FX (40 mg) was given at approximately 07.00 or 11.00 h, either alone or with intravenous Nal 3 h later, to normal human volunteers. Plasma ACTH and Cortisol levels were measured for 5 h after FX dosing. 3. Fluoxetine produced a small but non-significant increase in Nal-stiimilated ACTH and Cortisol release in both morning and afternoon studies. Naloxone alone did not cause different ACTH and Cortisol responses in the morning and afternoon. 4. These results suggest that serotonergic pathways are not major regulators of the hypothalamic-pituitary-adrenal axis in humans or that FX has counteracting acute inhibitory effects on the axis, such as inhibition of hypothalamic arginine vasopressin secretion, which has been demonstrated in chronic animal studies. 相似文献
1000.