Male meiotic segregation of gonosomes analysed by two colour FISH in human interphase spermatozoa

Human meiotic segregation of X and Y chromosomes was simultaneously analysed by dual fluorescence in situ hybridization (FISH) on 10,638 interphase spermatozoa from the same donor. A modified method for sperm decondensation ensured access of both X and Y probes to the sperm chromatin and a 99% hybridization efficiency. Expected sex ratios were obtained (49.30% haploidy X and 49.22% haploidy Y). The frequencies of meiotic II non-disjunctions for X and Y chromosomes (0.05%) were similar to those observed in sperm karyotypes after heterospecific fertilization of hamster eggs. In contrast, the frequency of XY bearing cells was significantly higher (0.42%). However, XY cells detected by FISH could either be diploid somatic cells, diploid germinal cells or hyperhaploid XY spermatozoa, the latter resulting from meiotic I non-disjunctions.

Adolescent running away behavior: active or passive avoidance?

One hundred seventeen boys and 149 girls participated in a study investigating whether adolescent running away behavior is an expression of passive (internalization) or active (externalization) avoidance. Results of principal component analyses indicate that boys' running away behavior is associated with passive avoidance and internalization, whereas for girls the behavior reflects a mixed pattern simultaneously expressing withdrawal and overt deviancy.

Achievement of meiosis in XXY germ cells: study of 543 sperm karyotypes from an XY/XXY mosaic patient

Human sperm chromosomes from a 46,XY/47,XXY male were obtained using the technique of in vitro penetration of zona-free hamster eggs. The analysis of 543 sperm complements shows a significantly increased incidence (0.9%) of hyperhaploid gonosomal 24,XY sets, with a lack of the expected corresponding gonosomal hypohaploidies, and a normal rate of autosomal non-disjunctions. These results support the suggestion that 47,XXY cells are able to go through meiosis and to form spermatozoa. Only 24,XY sperm chromosomal constitutions were observed suggesting a preferential pairing of homologous sex chromosomes in 47,XXY spermatocytes.

Practical magnetron sputtering system for the deposition of optical multilayer coatings

A magnetron sputtering system is described in which, at any one time, as many as four different 15-cm x 46-cm rectangular planar magnetron targets can be mounted vertically in the deposition chamber. These can be attached to either dc or rf power supplies for direct or reactive deposition of metal, metal oxide, or nitride films. Typical target materials include Ag, Al, C, Mo, Nb, Ni, Si, W, and Zr. Good uniformity can be obtained on stationary substrates, although better results are possible with oscillating substrates. The refractive indices are given for several useful oxide materials. The materials and thicknesses of the individual layers that comprise an optical multilayer system are entered into a computer that subsequently controls the deposition parameters, the substrate motion, and the deposition time. After a relatively simple calibration process, coatings that consist of between 20 and 60 layers can be produced to within an accuracy of 1% or 2%. A wideband optical monitor is available for checking the performance of the multilayer system during its deposition. Several examples of multilayer coatings that were prepared on this equipment are given.

Incoordination in patients with hemiparesis

Incoordination is frequently observed in patients following a cerebrovascular accident. Clinical electromyographic studies which have furthered our understanding of this motor impairment are reviewed, and possible underlying mechanisms are discussed. It is suggested that the lack of coordinated voluntary movement observed in hemiparetic patients may be due, in part, to an impaired regulation of spinal neurones. In the rehabilitation sciences, the need to assess the effectiveness of treatment as well as develop new approaches for the treatment of hemiparetic subjects will require the combined efforts of many investigators. A two-fold research approach is supported which aims: 1) to quantify the motor deficit, and 2) to extend our knowledge of the physiological mechanisms underlying the deficit. Such a general research approach could be of value to the study of other sensorimotor deficits.

The empirical testing of Harter's self-concept matrix on female adult students

This research aimed at testing an hypothetical matrix to be used for the study of self-concept development within a life-span perspective. Following data categorization collected from 111 female university students, a significant relationship was found between structural levels and content dimensions, demonstrating a linear form of development. Also several content dimensions were often used in subjects' self-definitions, illustrating the multidimensional aspect of such development in adults.

Do ischemic hearts stimulate endothelial cell growth?

The development of myocardial ischemia is known to elicit the formation and enlargement of collateral vessels. The stimulus for these events is unknown. We have investigated the possibility that cardiac tissue releases a factor that can stimulate endothelial cell proliferation. Hearts from New Zealand rabbits were made progressively ischemic by differential hypothermia. Extracts from these hearts were tested for their growth-stimulating ability and were found to increase the proliferation of fetal bovine aortic endothelial cells as well as DNA synthesis by 3T3 cells. The level of activity in the extracts appears to be related to the degree of ischemia as measured by creatine phosphokinase levels. The liberation of an endothelial cell growth factor by ischemic cardiac tissue may function in the initiation and/or potentiation of coronary collateral formation.

Legionnaires' disease: the epidemiology of two outbreaks in Burlington, Vermont, 1980

Eighty-five cases of Legionnaires' disease were diagnosed in two major outbreaks at a large regional medical center in Burlington, Vermont, in the summer of 1980. Cases in both outbreaks were positive for Legionella pneumophila, serogroup 1 by culture, serology, or direct fluorescent antibody tests. All cases had spent time in the city of Burlington in the 10 days before the onset of symptoms. Cases in both outbreaks were both hospital- and community-acquired. A case-control study identified no common in-hospital exposure, including shower use, that was associated with illness. Cases without previous exposure to the hospital were more likely to occur in persons with residences in neighborhoods just downwind of cooling tower A, but not throughout the municipal water system. Epidemiologic and environmental studies supported the association of this cooling tower, located 150 m from the hospital, with both outbreaks. Maintenance employees who worked with tower A had higher Legionella titers than those who worked with a comparison tower located 1.6 km away. Aerosolization of L. pneumophila by tower A and airborne spread to the hospital and community are postulated. The distance of airborne transmission of L. pneumophila in these consecutive outbreaks is greater than previously reported.

Hépato-néphrose puerpérale bovine

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[Clinical case. Reduction of a diaphragmatic hernia in a dairy cow]

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[Surgical correction of the leftward displacement of the abomasum]

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Action synergétique de la pénicilline et du sulfathiazole dans un cas de charbon symptômatique chez une génisse

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