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91.
Päivi Heikkilä Arvi I. Kahri Christian Ehnholm Petri T. Kovanen 《In vitro cellular & developmental biology. Plant》1988,24(9):936-942
Summary To define the role of endogenously synthesized cholesterol in the differentiation of adrenocortical cells in primary culture,
fetal rat adrenal cells were cultured in the presence of exogenous cholesterol (serum-supplemented medium) or in the absence
of it (serum-free medium or lipoprotein-free medium). Ultrastructurally the cells had features of glomerulosa cells: mitochondria
were oval or rod shaped with lamellar inner membranes. The amount of smooth endoplasmic reticulum was small, and lipid droplets
were few. When the cells were cultured in serum-free medium some intracytoplasmic vacuoles were seen. The undifferentiated
zona glomerulosa-like cells secreted low amounts of corticosterone and 18-OH-deoxycorticosterone (18-OH-DOC) in all three
media (serum-supplemented medium, serum-free medium, and lipoprotein-free medium). Stimulation of the adrenocortical cells
with ACTH induced the ultrastructural features of differentiated zona fasciculata-like cells. Mitochondrial inner membranes
were well developed in lipoprotein-free medium, but not in serum-free medium. The amount of intracellular lipids was increased
in both media devoid of cholesterol. In the ACTH stimulated cultures the presence of exogenous cholesterol resulted in increased
secretions of corticosterone and 18-OH-DOC. In the absence of an exogenous source of cholesterol, the amounts of steroids
secreted were only half of that secreted in the presence of serum-supplemented medium. Endogenously synthesized cholesterol
is sufficient for the morphologic differentiation of fetal rat adrenocortical cells under ACTH stimulation. However, without
exogenously provided cholesterol, the steroid production accounts only for half of the maximal output achieved using serum-supplemented
medium.
This work was supported by Finnish Culture Foundation. 相似文献
92.
Karin Lindström Albert E. G. Kr. Von Dem Borne Michael E. Breimer Bertil Cedergren Yasuto Okubo Lennart Rydberg Susann Teneberg Bo E. Samuelsson 《Glycoconjugate journal》1992,9(6):325-329
A 12-week-old fetus and one 17-week-old fetus + placenta were obtained after spontaneous abortions from two women of blood group p. The 17-week-old fetus was dissected into intestine, liver, brain and residual tissue. Nonacid glycosphingolipid fractions were prepared from the tissues. Glycolipid characterization was carried out using thin layer chromatography immunostained with monoclonal antibodies and bacteria and by1H NMR spectroscopy and mass spectrometry. In the placental fraction substantial amounts of globotetraosylceramide (P-antigen) and globotriaosylceramide (Pk-antigen) were identified. In contrast, the fetuses contained only trace amounts of these structures, as revealed by immunostaining. These results indicate that the primary target for the antibodies of the anti-Tja serum is the placenta tissue, resulting in termination of the pregnancy. 相似文献
93.
Summary Two monoclonal antibodies directed against somatostatin 14 were used to study immunoreactive neurons, their processes and their synapses in the cat retina. In retinal whole-mounts, a sparse population of wide-field displaced amacrine cells was observed predominantly in the ventral retina and near the retinal margin. Processes of these cells ramified mainly in two distinct strata within the inner plexiform layer: one near the inner nuclear layer (INL), and the other near the ganglion cell layer (GCL). The length of immunoreactive fibres within each plexus was measured: 232±32 mm/mm2 near the INL and 230±74 mm/mm2 near the GCL in all retinal regions. The immunoreactive processes were studied using electron-microscopic techniques; conventional and some ribbon-containing synapses (dyads) were found. Immunolabelled processes received input synapses from other amacrine cell processes. These investigations provide further evidence that this cell population has a diffuse, regulatory or modulatory role for visual-information processing in the inner plexiform layer. 相似文献
94.
95.
Aino Laatikainen Leslie Schultz-Suhonen Rauno Mäntyjärvi 《Cancer immunology, immunotherapy : CII》1992,35(3):205-210
Summary The effect of interferon (IFN) on the immunogenicity and immunosensitivity of mouse cell lines transformed by bovine papillomavirus type 1 (BPV1) DNA was examined in a syngeneic mouse model. The overnight incubation of BPV1-transformed cell lines with 100 IU/ml IFN did not affect their ability to induce the generation of cytotoxic effector cells but it clearly increased their sensitivity to lysis by interleukin-2-induced lymphokine-activated killer (LAK) cells and by nonspecific LAK-type effector cells induced by BPV-1-transformed cell lines. The treatment of two allogeneic lymphoid tumour cell lines, P815X2 and YAC-1, with IFN either decreased or had no effect on their sensitivity to LAK-cell-mediated lysis. 相似文献
96.
Günter Kämper 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1992,170(1):49-55
Summary Mechanical oscillation properties of cricket (Acheta domesticus) filiform hair sensilla were measured at different larval stages, as an indication of larval sensory capacities and for comparison with data in the literature on central nervous changes during development. The hairs were stimulated by airborne vibration over a frequency range of 10 to 220 Hz. Best frequency, angular displacement at best frequency, slope of angular-displacement tuning curve and phase of hair deflection relative to air particle velocity were tested for correlation with hair length, which is proportional to the age of a sensillum. The ranges found for the various oscillation parameters in early larval stages were similar to or larger than those in adults. Oscillation properties changed with both the developmental stage of the hair sensilla and that of the whole animal. Four individually identifiable hair sensilla were analysed separately; the sensory neurons of two of them are known to change synaptic properties during maturation. Angular displacement at a given stimulus intensity was maximal for all hairs after differentiation, and decreased during further development. The hairs did not show clear common changes for any of the other oscillation parameters. Yet particular changes were found for individual hairs. 相似文献
97.
Maria Anvret Margareta Blombäck Monika Lindstedt Elisabeth Söderlind Margareta Tapper-Persson Ann-Christine Thelander 《Human genetics》1992,89(2):147-154
Summary Twenty-five patients with von Willebrand's disease (vWD) type III were analysed with regard to blood coagulation variables and possible deletions. Nine of the probands and their families were further investigated with DNA linkage analyses. Different patterns of heredity can be suggested in our families with vWD type III, on the basis of blood coagulation analyses. The findings suggest homozygosity in five families and the possibility of compound heterozygosity or a new mutation in the proband in three families. The linkage analyses confirm the results of the coagulation analyses. The segregation of the von Willebrand factor (vWF) gene can be followed in the families, and carrier diagnosis can be made in several of the probands' relatives. The possibility of large deletions in the vWF gene of the probands and their parents was investigated with probes representing the whole vWF cDNA. No deletions were found.This study was approved by the Ethics Committee of the Karolinska Hospital (No. 84:1) 相似文献
98.
Summary Confined placental chorionic mosaicism is reported in 2% of viable pregnancies cytogenetically analyzed on chorionic villi samplings (CVS) at 9–12 weeks of gestation. In follow-up studies this mosaicism has been shown to be associated with increased frequency of second and third trimester pregnancy loss or intrauterine fetal growth retardation. We have studied 54 spontaneous abortions (SA) for the detection of confined placental mosaicism and found 11 of them to be mosaic. All mosaic cases were identified among first trimester spontaneous abortions, and the mosaicism was confined to specific placental or embryonic/fetal cell lineages. These results indicate that the previously reported mosaicism in SA represents both confined and generalized types of mosaicism and that its accepted frequency of 5%–10% in SA will likely be higher. Over the whole gestational period, the confined placental mosaicism is more common than the reported rate of 1%–2% seen in viable pregnancies at CVS, and a higher proportion of pregnancy complications than previously suspected may be associated with confined placental mosaicism. 相似文献
99.
J. Hundrieser P. Nürnberg A. E. Czeizel Julia Métneki Siegrid Rothgänger H. Zischler J. T. Epplen 《Human genetics》1992,90(1-2):27-33
Summary Population genetic studies were performed using oligonucleotide probes (Hz1103, Hz4103, and Hz4201) that recognize three hypervariable loci (D11S859, D9S128 and D22S265) in the human genome. DNA from 17 Eurasian population samples including 37 monozygotic twin pairs were digested with HinfI and hybridized with Hz4103. Allele frequency distribution profiles and high degrees of heterozygosity were similar in each ethnic group. Among 804 unrelated individuals tested, we detected one case of mosaicism caused by a somatic recombination event in a monozygotic twin. In addition, samples of DNA from three ethnic groups (Germans, Assamese Hindus and Thais) and from German and Thai families were restricted with MboI and probed with Hz1103, Hz4103, and Hz4201. The results showed considerable degrees of heterozygosity and locus-specific allele distribution profiles, rather than interpopulation differences. Among 262 meioses (12 three-generation families with a total of 131 children) analyzed, a single recombination event was observed following hybridization with the DNA probe Hz4201. 相似文献
100.
Ingemar Näslund 《Environmental Biology of Fishes》1992,33(3):265-274
Synopsis Extensive upstream migration of landlocked Arctic charr during spring floods was recorded in several tributaries of an oligotrophic lake in north-west Sweden. Migration was confined to a period of about two weeks and residence in most creeks was of short duration. Only fish migrating to two small productive lakes remained in the new habitat over the summer. Repeated annual migrations were only recorded in the creek leading to these lakes and no straying was observed among repeat migrants. Water temperatures provided the primary cues for initiation and direction of migration, although an ability to detect productive habitats by odour was indicated. Creek size, feeding opportunities during migration and conspeeific odour were subordinate guiding factors. 相似文献