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991.
Doris Kavanagh-Gray 《CMAJ》1963,89(10):491-499
The case histories of seven infants with atrial septal defect are presented to draw attention to certain features and possible dangers of this defect in infancy. Four infants were asymptomatic but one failed to thrive and two died suddenly. Five had ejection murmurs and two, with pulmonary hypertension, had loud pan-systolic murmurs with a thrill. In two infants murmurs were noted at birth, but in five they were first heard between the ages of 1 and 6 months. The second pulmonary sound was initially narrowly split in all, but became widely split between the ages of 12 and 20 months. Electrocardiograms and chest roentgenograms were of little help at the outset but later showed findings characteristic of the defect after one year. All infants were catheterized; a left-to-right atrial shunt was detected in each instance. Pulmonary hypertension was present in two infants, one of whom died. 相似文献
992.
Structure-function analysis of the Abm12 beta mutation using site-directed mutagenesis and DNA-mediated gene transfer 总被引:5,自引:0,他引:5
The B6.C-H-2bm12 (bm12) mouse possesses a naturally occurring mutation in its class II MHC A beta gene. The three amino acid substitutions at positions 67, 70, and 71 that comprise this mutation lead to changes in both Ia expression and immune recognition of the resultant A beta A alpha molecule. The experiments reported here utilize a combination of oligonucleotide-mediated site-directed mutagenesis and DNA-mediated gene transfer to explore the roles played by each of the three mutant residues in these various phenotypic changes. A beta genes comprising all permutations of the residues distinguishing Ab beta from Abm12 beta were created and were individually co-transfected with Ab beta into mouse L cells. Sublines expressing high levels of membrane Ia were selected by preparative flow cytometry and were studied for reactivity with a panel of monoclonal anti-Ia antibodies, or for their ability to act as antigen-presenting cells (APC) for the stimulation of T cell hybridomas. During the generation of these transfectant lines, it was noted that expression of a high level of Abm12 beta Ab alpha was more difficult to achieve than a similar level of Ab beta Ab alpha. Northern blot analysis of specific A beta and A alpha mRNA levels in these various lines indicated that more class II mRNA, and presumably more A beta and A alpha chains, were required to achieve expression of Abm12 beta Ab alpha equal to that of Ab beta Ab alpha, suggesting that the previously noted reduction of Ia expression on cells from bm12 mice reflects a decreased ability of Abm12 beta Ab alpha chains to pair, or to reach the membrane. Staining of the panel of transfectants with monoclonal antibodies revealed that antibodies which did not distinguish Ab beta Ab alpha from Abm12 beta Ab alpha also reacted equally well with all molecules involving in vitro mutant A beta chains. Monoclonal antibodies reactive with Ab beta Ab alpha but not Abm12 beta Ab alpha were specific for an epitope primarily determined by the presence or absence of Arg 70 in Ab beta. In striking contrast, all three mutant positions were found to play crucial roles in T cell recognition, because all substitutions led to significant or complete loss of antigen-presenting function with all but one of the T hybridomas tested.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
993.
Callus cultures were derived from stems and leaves of 3 anthocyanin producing and 3 acyanic lines of Callistephus chinensis (Compositae). The tissue cultures of the cyanic lines were shown to produce cyanidin whereas in the calli of the acyanic lines no anthocyanin synthesis occurred Culture conditions were improved in order to enhance both anthocyanin production and growth of the tissue cultures.Abbreviations IAA
indoleacetic acid
- NAA
naphtaleneacetic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid
- MS-medium
Murashige and Skoog medium 相似文献
994.
Cell of origin of distinct cultured rat liver epithelial cells, as typed by cytokeratin and surface component selective expression 总被引:5,自引:0,他引:5
N Marceau L Germain R Goyette M No?l H Gourdeau 《Biochimie et biologie cellulaire》1986,64(8):788-802
The cell of origin of the nonparenchymal epithelioid cells that emerge in liver cell cultures is unknown. Cultures of rat hepatocytes and several types of nonparenchymal cells obtained by selective tissue dispersion procedures were typed with monoclonal antibodies to rat liver cytokeratin and vimentin, polyvalent antibodies to cow hoof cytokeratins and porcine lens vimentin, and monoclonal antibodies to surface membrane components of ductular oval cells and hepatocytes. Immunoblot analysis revealed that, in cultured rat liver nonparenchymal epithelial cells, the anti-rat hepatocyte cytokeratin antibody recognized a cytokeratin of relative mass (Mr) 55,000 and the anti-cow hoof cytokeratin antibody reacted with a cytokeratin of Mr 52,000, while the anti-vimentin antibodies detected vimentin in both cultured rat fibroblasts and nonparenchymal epithelial cells. Analyses on the specificity of anti-cytokeratin and anti-vimentin antibodies toward the various cellular structures of liver by double immunofluorescence staining of frozen tissue sections revealed unique reactivity patterns. For example, hepatocytes were only stained with anti-Mr 55,000 cytokeratin antibody, while the sinusoidal cells reacted only with the anti-vimentin antibodies. In contrast, epithelial cells of the bile ductular structures and mesothelial cells of the Glisson capsula reacted with all the anti-cytokeratin and anti-vimentin antibodies. It should be stressed, however, that the reaction of the anti-vimentin antibodies on bile ductular cells was weak. The same analysis on tissue sections using the anti-ductular oval cell antibody revealed that it reacted with bile duct structures but not with the Glisson capsula. The anti-hepatocyte antibody reacted only with the parenchymal cells. The differential reactivity of the anti-cytokeratin and anti-vimentin antibodies with the various liver cell compartments was confirmed in primary cultures of hepatocytes, sinusoidal cells, and bile ductular cells, indicating that the present panel of antibodies to intermediate filament constituants allowed a clear-cut distinction between cultured nonparenchymal epithelial cells, hepatocytes, and sinusoidal cells. Indirect immunofluorescence microscopy on nonfixed and paraformaldehyde-fixed cultured hepatocytes and bile ductular cells further confirmed that both anti-hepatocyte and anti-ductular oval cell antibodies recognized surface-exposed components on the respective cell types.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
995.
G Germain P Lopes D Cabrol M P Barbe D Huneau R Le Houezec C Sureau 《Acta physiologica Hungarica》1986,67(1):95-115
The use of a combination of manometric and electromyographic methods provided a reliable technique for evaluating variations in uterine activity in conscious macaque monkeys and women. The technique was particularly useful for obtaining data on the influence of steroid hormones. During the spontaneous menstrual cycle of the macaque, uterine motility, after being weak and poorly synchronized during the follicular phase, became still weaker with impaired synchronization during the luteal phase and then much stronger and well-synchronized at the time of menstruation. There was no evidence in vivo of any relationship between the existence of gap junctions in the myometrium of non-pregnant animals and the various patterns of uterine motility. During the last third of pregnancy in macaques, the initiation of electrical activity in various uterine areas was always synchronous with and related to mechanical contraction. The same results were obtained in preparturient women. Thus, improved uterine coordination does not appear to be the mechanism by which the uterine contractile strength increases to expulse the foetus at the end of pregnancy. Apart from the particular situation of non-pregnant animals under progestative influence, in which activity was constantly non-propagated, we could not find any evidence of a general pattern which would indicate only one site for the initiation of activity and its extension to the whole uterus. 相似文献
996.
997.
R I Lechler V Bal J B Rothbard R N Germain R Sekaly E O Long J Lamb 《Journal of immunology (Baltimore, Md. : 1950)》1988,141(9):3003-3009
Murine L cells expressing the products of transfected HLA-DR1 genes functioned as APC for two influenza-specific, human Th cell clones with comparable efficiency to a DR1-expressing human lymphoblastoid cell line. In order to investigate the restriction specificity of the two Th clones, a transfectant expressing the species-mismatched MHC class II dimer DR1:I-E was tested as an APC. Both T cells showed no loss of Ag sensitivity due to substitution of the murine chain. One of the Th clones, TLC 72, showed even greater degeneracy by responding to Ag in the context of I-Ek. Taking into account the lower level of MHC class II expression on the I-Ek transfectant, there is remarkably little loss of efficiency of Ag-induced T cell activation due to the substitution of I-E for DR as restriction element. The Ag-specific responses of both clones were inhibited by anti-CD4 antibody when DR-transfected L cells or human lymphoblastoid cells were used as APC. This inhibition was also seen when Ag was presented to TLC72 by the I-Ek-expressing transfectant. Whether this inhibition is the result of negative signaling or of blocking an interaction between human CD4 and I-Ek is discussed. Similarly the inhibitory effects of mAb against the T cell accessory molecule LFA/1 were the same for both clones when either the transfectants or the lymphoblastoid cell line were used as APC, suggesting that L cells may express a molecule that is capable of acting as a ligand for human LFA/1. The results presented here further illustrate the value of transfectants in analyzing T cell recognition and accessory cell requirements. The patterns of degeneracy of MHC restriction exhibited by these clones provides a platform for a more detailed analysis of key residues involved in MHC class II-restricted T cell Ag recognition. 相似文献
998.
Eight groups of rhesus monkeys each consisting of one male and four ovariectomized females were observed while two of the
females were treated with hormones to produce artificial menstrual cycles. These were either synchronized or offset by 7-day
increments. Sexually preferred females, defined by the numbers of ejaculations per test, received almost twice as many ejaculations
as did non-preferred females during all synchronized and offset cycles and during all cycle phases. However, short-term changes
in partner preference occurred when the midcycle phase of non-preferred females coincided with the middle or late progesterone
phase of preferred females, suggesting a negative effect of progesterone on behavior during the menstrual cycle. There were
highly significant differences between preferred and non-preferred partners for almost all of their sexual and social interactions,
and preferred partners showed longer proximity and grooming times as well as higher levels of sexual activity. Partner preferences
accounted for more of the behavioral variance between pairs than did female dominance, although males sought the proximity
of dominant females independently of their partner preferences. Thus, in a setting uncomplicated by male mate competition,
sexual preference by male rhesus monkeys is a robust phenomenon depending on complex interactions between dominance, hormonal
status, and the individual behavior of female partners. 相似文献
999.
1000.
Role of different epithelial cell types in liver ontogenesis,regeneration and neoplasia 总被引:6,自引:0,他引:6
Normand Marceau Marie-José Blouin Lucie Germain Micheline Noel 《In vitro cellular & developmental biology. Plant》1989,25(4):336-341
This work is supported by the National Cancer Institute of Canada. 相似文献