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21.
David E. Scott David H. Van Dyke Willis K. Paull Gerald P. Kozlowski 《Cell and tissue research》1974,150(3):389-397
Summary The ultrastructural organization of the human fetal choroid plexus was assessed with scanning electron microscopy. The membranous modifications of choroidal ependymal cells differ remarkably between 11 and 20 weeks of intrauterine development and suggest a variable functional capacity at different times of ontogenesis. Based upon existing data coupled with the ultra-architectural organization of cilia, clavate and linear microvilli are seen with scanning electron microscopy, a multiple functional role is hypothesized for choroidal ependymal cells.supported by USPH grant NS 08171.career development awardee K04 GM 70001 相似文献
22.
Successful breeding of the giant panda (Ailuropoda melanoleuca) following artificial insemination was achieved at the Ueno Zoo in 2 consecutive years (1985 and 1986). The first cub, born in June 1985, unfortunately died 43 hours after birth from being crushed by the mother panda; the second cub, born in June 1986, has been growing in good health. Electroejaculation and artificial insemination procedures were performed after immobilization with diazepam (0.1 mg/kg) and ketamine HCL (4.0–5.0 mg/kg). Semen of the male panda was collected by electroejaculation using a rectal probe with a diameter of 2.0 cm and with eight rings as electrodes. Stimulation of the male was given with 3 V (30–40 mA) over a 5-sec period with 5-sec intervals. The female panda exhibited estrus between late February and early March in 1985 and also between mid-january and early February 1986. Increased excretion of urinary total estrogen showed coincidentally at maximum behavioral estrus, and a gradual rise of pregnanediol level was followed by artificial insemination. The gestational length for the first pregnancy was 110 days and that of the second 121 days. 相似文献
23.
[3H]Spiperone ([3H]SPI) binding sites in rat or bovine striata have been solubilized using CHAPS or digitonin detergents. Solubilized sites retained the binding characteristics of those in native membrane preparations. The same solubilized material, however, did not bind [3H]tyramine ([3H]PTA), thus indicating that [3H]PTA binding sites and DA receptors are different chemico-physical entities. In membrane preparations or crude synaptosomes obtained from the c.striatum of neonatally-rendered hypothyroid rats, when central DA-pathways are impaired, both [3H]PTA binding and [3H]DA uptake processes were markedly decreased, with no effect on [3H]mazindol ([3H]MAZ) binding, compared to euthyroids. Reserpine, a well-known inhibitor of DA-uptake into a variety of secretory vesicles, and a potent in vivo andin vitro inhibitor of [3H]PTA binding, did not affect the [3H]MAZ binding process. This further supported the suggestion that while [3H]PTA binding sites are almost totally associated with the vesicular transporter for DA, [3H]MAZ does label a site involved in the DA-translocation across the neuronal membrane. The latter process seems to be rather insensitive to thyroid hypofunction, when however the intracellular storage of DA might be consistently impaired. In conclusion, PTA might be well exploited as a marker of the DA vesicular transporter through its molecular characterization, whenever possible.Special issue dedicated to Dr. Paola S. Timiras 相似文献
24.
The pseudanthia ofHeliopsis scabra andRudbeckia vulgaris (Asteraceae) were examined during the anthesis for differences in their UV patterns. Distinct changes in the reflectance and absorbance properties could be observed. The results suggest a close correlation between different stages of floral development and pollinator attraction.
Herrn Prof. Dr.Lothar Geitler zum 90. Geburtstag gewidmet. 相似文献
25.
S. A. Masoud L. B. Johnson E. L. Sorensen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,79(1):49-55
Summary A high frequency of paternal plastid transmission occurred in progeny from crosses among normal green alfalfa plants. Plastid transmission was analyzed by hybridization of radiolabeled alfalfa plastid DNA (cpDNA) probes to Southern blots of restriction digests of the progeny DNA. Each probe revealed a specific polymorphism differentiating the parental plastid genomes. Of 212 progeny, 34 were heteroplastidic, with their cpDNAs ranging from predominantly paternal to predominantly maternal. Regrowth of shoots from heteroplasmic plants following removal of top growth revealed the persistence of mixed plastids in a given plant. However, different shoots within a green heteroplasmic plant exhibited paternal, maternal, or mixed cpDNAs. Evidence of maternal nuclear genomic influence on the frequency of paternal plastid transmission was observed in some reciprocal crosses. A few tetraploid F1 progeny were obtained from tetraploid (2n=4x=32) Medicago sativa ssp. sativa x diploid (2n=2x=16) M. sativa ssp. falcata crosses, and resulted from unreduced gametes. Here more than the maternal genome alone apparently functioned in controlling plastid transmission. Considering all crosses, only 5 of 212 progeny cpDNAs lacked evidence of a definitive paternal plastid fragment.Contribution No. 89-524-J from the Kansas Agricultural Experiment Station, Kansas State University, Manhattan 相似文献
26.
James F. Rieger 《Oecologia》1996,107(4):463-468
The timing of reproduction affected litter size, offspring mass, and offspring survival in the Uinta ground squirrel, Spermophilus armatus, in Grand Teton National Park, Wyoming. Survival of juvenile females to yearling age varied negatively with date of weaning and positively with individual offspring mass. At the same time, juveniles weaned early in the season were lighter, and juveniles weaned later in the season were heavier. The coefficient of variation for juvenile body mass, originally measured at weaning, significantly decreased by the time juveniles entered hibernation, indicating that individuals weaned early and light caught up in body mass to individuals weaned later and heavier. From the perspective of the mother's investment in the litter, litter size (corrected for mother's mass) decreased with later wcaning dates, while the relationship of weaning date to litter mass (corrected for mother's mass) was significant in only one year. Maternal allocation of resources in litters changed over the season so that mothers produced many, small offspring early in the season, and fewer, large offspring late in the season. 相似文献
27.
J. Des Forts 《International Journal of Anthropology》1996,11(2-4):123-136
For millenaria, maternal mortality has been considered as a fatality inherent to women's condition. Thanks to the progress of the obstetric technology, the world M.M.R. fell from 2.000 to 400 per 100.000 births during the past 150 years. At the same time women's condition improved chiefly because of a better level of education. Is there any relationship between them: the decrease of Maternal Mortality and the amelioration of women's general status? Or, in other words, can the decrease of Maternal Mortality Rate be considered as an “indicator” of the situation of women? After a historical review of the importance of the maternal mortality drama as it occured in older times before the “obstetric era”, which began with the improvement of the obstetric technology, this paper will present the actual situation of maternal mortality in relation with the obstetric coverage, the female literacy level and some other socio-economic variables, and in relation with the Gross National Product (G.N.P.) as an indicator of governmental interest in the specific female problems of giving-life. 相似文献
28.
Yasmin H. Neggers Mary B. Dubard Robert L. Goldenberg Tsunenobu Tamura Kelley E. Johnston Rachel L. Copper John C. Hauth 《Biological trace element research》1996,55(1-2):127-135
Plasma zinc (Zn) concentrations were measured in 4376 indigent women (86% African-American), at a mean (±SD) gestational age
of 15 (±7.8) wk to determine the relationship between various maternal characteristics and plasma Zn levels during pregnancy.
Mean plasma Zn levels were lower in African-American women than in Caucasian women, in multiparous women than in primiparous
women, and in women with body weight >69.9 kg than in those with body weight ≤69.9 kg (p≤0.001 for each comparison). There were no significant differences related to maternal age, marital status, education, or
smoking habit. Multiple regression analysis, including maternal prepregnancy weight, race, age, parity, smoking habit, education,
and marital status indicated that race, parity, and pregnancy weight were significantly associated with maternal plasma Zn
levels, adjusted for gestational age. Maternal race was the best predictor of plasma Zn concentrations among the population
of pregnant women studied A significant proportion of variance in maternal plasma Zn levels remained unexplained after taking
into account various maternal characteristics. The reasons for lower plasma Zn levels in African-American women, compared
to Caucasian women, during pregnancy are unknown. 相似文献
29.
Alexandra M. Birrell Annemarie Hennessy Adrian Gillin John Horvath David Tiller 《Journal of medical primatology》1996,25(4):287-293
Abstract: Baboons are widely used in biomedical research. Although it is widely held that Papio hamadryas breed well in captivity, each established colony has a different reproductive success often hypothesised to be due to husbandry practices. The National Baboon Colony in Australia is a unique colony that houses Papio hamadryas to mimic that structure seen in the wild. In this article; we have analysed their reproductive parameters and neonatal outcomes. The success of the colony husbandry practices was demonstrated by lack of maternal mortality, low foetal morbidity, and known maternal and paternal linage. 相似文献
30.
Katherine J. Devonald Winthrop J. Harewood David A. Ellwood Andrew F. Phippard 《Journal of medical primatology》1996,25(5):339-345
Normal biometric ranges for fetal growth in a captive breeding baboon (Papio hamadryas) colony are described. Measurements include crown-rump length, biparietal diameter, binocular distance, head circumference, abdominal circumference, femur length and amniotic fluid index. The pattern of fetal growth is compared with other baboon subspecies and man. The uses and limitations of such data for breeding colony management and optimum utilisation of experimentally derived data are discussed. 相似文献