Cytogenetics of human oocytes,zygotes, and embryos after in vitro fertilization

Summary Chromosome errors, inherited or arising de novo during gametogenesis and transmitted at fertilization to the conceptus, may be a major cause of embryonic mortality. The in vitro fertilization and embryo transfer (IVF/ET) procedure provides extra material — oo-cytes, zygotes, and embryos — to investigate the contribution of chromosomal abnormality to implantation failure. This paper reviews the results of cytogenetic studies on such material. Estimates from a total of 1120 oocytes from 11 studies give an overall proportion of chromosomal abnormality of 35%. Single and multiple nullisomies and disomies are found, involving nonrandom chromosome gain or loss. Hypohaploid complements are more frequent than hyperhaploid complements. The higher rate of chromosome loss of hypohaploid karyotypes was found to be largely artifactual. The estimated overall frequency of aneuploidy is 13%. In embryos the level of chromosomal abnormality is 23%–40%. Errors of fertilization are responsible for a substantial number of triploid embryos, many of which develop into mosaics. Factors extrinsic to the conceptus, such as infertility, advanced maternal age, and ovarian hyperstimulation, may increase the level of chromosomal abnormality. More refined methods for accurately recognizing and selecting chromosomally normal embryos for transfer are needed to improve the success rate of this reproductive technology.     

Sequential changes in lung metabolism, permeability, and edema after ANTU

Lung injury and pulmonary edema were induced in rats after intraperitoneal injection of 10 mg/kg alpha-naphthylthiourea (ANTU). The time course of development of lung injury was assessed by the clearance of 99mTc-diethylenetriamine pentaacetate (99mTcDTPA) from the lung into the blood, the pharmacokinetics of tritiated prostaglandin E2 [( 3H]PGE2) in the isolated perfused lung, and by increase in the weight ratio (wet-to-dry) of lung. Two hours after ANTU administration, the clearance of 99mTcDTPA was significantly faster than in untreated animals and implied an increase in permeability of the alveolar-capillary barrier. This change preceded the increase in wet-to-dry weight ratio of lung, which was not significant until 5 h after ANTU administration. The pharmacokinetics of [3H]PGE2 were significantly altered after ANTU and these changes persisted beyond the time when both lung weight ratio and 99mTcDTPA clearance had recovered to normal values. We conclude that both 99mTcDTPA clearance and PGE2 pharmacokinetics change in ANTU-induced lung injury but with different time courses. In the progressive phase of lung injury due to ANTU, the early change in clearance of 99mTcDTPA suggests that an increased permeation of the alveolar capillary barrier by this small molecule precedes pulmonary edema due to an increased colloid permeability of the barrier. Abnormal metabolism in the pulmonary microvasculature persists when the permeability defect and edema have recovered.     

Extraction,regeneration after bleaching,and ion-exchange chromatography of rhodopsin in Tween 80

Rhodopsin can be readily and somewhat, selectively extracted into Tween 80 solutions from the isolated photoreceptor particulate fraction of bovine retinal tissue. Approximately 80% of the rhodopsin is recovered from the particulate fraction with A₄₉₈ values of approximately 6 and spectral ratios (A₂₇₈:A₄₉₈) of 1.8-1.9. The solutions are estimated to be approximately 97% pure based upon assay of protein and rhodopsin content and 98% pure based upon chromatography on DEAE-cellulose. The bulk of the rhodopsin can be regenerated after bleaching in Tween 80. Partial regenerability is retained when solutions of unbleached or bleached rhodopsin in Tween 80 are further purified by DEAE-cellulose chromatography.     

Integration of Functional,Psychophysiological, and Biochemical Processes in Athletes after Audiovisual Stimulation

We studied intra- and inter-system structural interactions between functional, psychophysiological, and biochemical processes in athletes after audiovisual stimulation (AVS). We used multiple linear regression and correlation analysis after AVS to investigate the formation of new relations between the nervous, hormonal, cardiorespiratory, and metabolic systems. AVS training leads to an increase in physical working capacity (PWC₁₇₀) and in the number of its correlations, e.g., with the amplitude of alpha-rhythm, resting heart rate (HR), concentrations of thyroxine, phosphorus, glucose, bilirubin, and triglycerides, antioxidant status, and the level of life satisfaction, which indicates the elevation in inter-system integration processes at different functional levels. An increase in the number and effects of factors contributing to PWC₁₇₀ (chronoinotropic reserve, lung capacity, reaction of individual α-rate power depth, reaction to the moving object, and the concentrations of glucose, creatinine, bilirubin, and thyroxine) eventually resulted in higher PWC₁₇₀. This indicates that the rate of synchronization between the studied parameters increases under the influence of sensory impact, which results in the improvement of adaptive capacity and provides a lower cost of adaptation to physical loads at the competitive stage of sports training.     

Carbohydrate nutrition before, during, and after exercise

The role of dietary carbohydrates (CHO) in the resynthesis of muscle and liver glycogen after prolonged, exhaustive exercise has been clearly demonstrated. The mechanisms responsible for optimal glycogen storage are linked to the activation of glycogen synthetase by depletion of glycogen and the subsequent intake of CHO. Although diets rich in CHO may increase the muscle glycogen stores and enhance endurance exercise performance when consumed in the days before the activity, they also increase the rate of CHO oxidation and the use of muscle glycogen. When consumed in the last hour before exercise, the insulin stimulated-uptake of glucose from blood often results in hypoglycemia, greater dependence on muscle glycogen, and an earlier onset of exhaustion than when no CHO is fed. Ingesting CHO during exercise appears to be of minimal value to performance except in events lasting 2 h or longer. The form of CHO (i.e., glucose, fructose, sucrose) ingested may produce different blood glucose and insulin responses, but the rate of muscle glycogen resynthesis is about the same regardless of the structure.     

Transmembrane helices before, during, and after insertion

The transmembrane (TM) helix is the fundamental structural unit of helix-bundle membrane proteins. Recent biophysical studies provide new insights into the interactions of TM helices with each other and with membrane lipid bilayers. The biological process of helix insertion is carried out by translocon complexes acting in concert with ribosomes. An electron cryo-microscopic reconstruction of these complexes reveals their architecture in new detail, and shows that the complex is constructed from four SecY/Sec61 heterotrimers and two TRAP complexes. A disulfide bridge study shows that elongating polypeptide chains pass through the pore previously identified in the X-ray structure of an archaeal SecY heterotrimer. The fundamental code used by the translocon to select polypeptide segments for insertion as TM helices has been broken. A detailed analysis of the TM amino acid distributions of helix-bundle membrane proteins of known structure recapitulates this code.     

Injury,inflammation, and remodeling in fetal sheep lung after intra-amniotic endotoxin

Chorioamnionitis is frequent in preterm labor and increases the risk of bronchopulmonary dysplasia. We hypothesized that intra-amniotic endotoxin injures the lung in utero, causing a sequence of inflammation and tissue injury similar to that which occurs in the injured adult lung. Preterm lamb lungs at 125 days gestational age were evaluated for indicators of inflammation, injury, and repair 5 h, 24 h, 72 h, and 7 days after 4 mg of intra-amniotic endotoxin injection. At 5 h, the epithelial cells in large airways expressed heat shock protein 70, and alveolar interleukin-8 was increased. Surfactant protein B (SP-B) decreased in alveolar type II cells at 5 h, and SP-B in lung tissue and alveolar lavage fluid increased by 72 h. By 24 h, neutrophils were recruited into the large airways, and cell death was the highest. Alveolar type II cells decreased by 25% at 24 h, and proliferation was highest at 72 h, consistent with tissue remodeling. Intra-amniotic endotoxin caused surfactant secretion, inflammation, cell death, and remodeling as indications of lung injury. The recovery phase was accompanied by maturational changes in the fetal lung.     

IL-8 in septic shock, endotoxemia, and after IL-1 administration

Much effort has been directed toward elucidating the host response to sepsis and inflammation, resulting in the definition of a cascade of endogenous mediators that direct metabolic and immunological responses. Here we report that IL-8, a novel cytokine produced by a variety of cells in vitro in response to stimulation with bacterial LPS and the proinflammatory cytokines, appears in the circulation of primates in vivo during septic shock, sublethal endotoxemia, and after the administration of IL-1 alpha. The magnitude of the IL-8 response correlates with the severity of the insult, and levels of IL-8 peak relatively late, after those of TNF-alpha and IL-1 beta, and simultaneously with those of IL-6. IL-8 has been primarily defined as a selective activator and chemoattractant of neutrophils, and we demonstrate that after LPS or IL-1 alpha infusion, circulating neutrophil numbers rapidly recover from an initial neutropenia while IL-8 concentrations are maximal, supporting the hypothesis that IL-8 influences circulating leukocyte populations in vivo. We conclude that IL-8 is another participant in the cytokine cascade elicited by sepsis and inflammation and, as such, may play a significant role in host defense and disease.