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排序方式: 共有808条查询结果,搜索用时 15 毫秒
761.
762.
763.
Matulonis UA; Dosiou C; Lamont C; Freeman GJ; Mauch P; Nadler LM; Griffin JD 《Blood》1995,85(9):2507-2515
A costimulatory signal from B7-1 (CD80) to its counter-receptor CD28 is required for T-cell activation. Many tumors, including most human leukemias, lack expression of B7-1, and this has been suggested to contribute to the failure of immune recognition of these diseases. A murine leukemia model system was developed to assess the potential role of B7-1 in the induction immunity to leukemia cells. The nonleukemic 32Dc13 myeloid cell line was transformed by transfection of the BCR/ABL gene, generating a subline (32Dp210/clone 26) that was leukemic and rapidly lethal to syngeneic, immunocompetent C3H/HeJ mice or T-cell- deficient nude mice. B7-1-modified leukemic cells remained lethal in nude mice, but caused only a transient, nonlethal leukemia in C3H/HeJ mice. After a single exposure to live, nonirradiated B7-1-modified leukemic cells, C3H/HeJ mice developed protective immunity against subsequent challenge with B7-1(-) leukemic cells. Further, hyperimmunization with B7-1(+) leukemic cells prolonged the survival of mice previously injected with a lethal number of B7-1(-) leukemic cells. These results indicate that myeloid leukemic cells may be attractive candidates for B7-1 gene transfer. 相似文献
764.
765.
Juul A; Scheike T; Pedersen AT; Main KM; Andersson AM; Pedersen LM; Skakkebaek NE 《Human reproduction (Oxford, England)》1997,12(10):2123-2128
Few studies exist on the physiological changes in the concentrations of
growth hormone (GH), insulin-like growth factors (IGF) and IGF-binding
proteins (IGFBP) within the menstrual cycle, and some controversy remains.
We therefore decided to study the impact of endogenous sex steroids on the
GH-IGF-IGFBP axis during the ovulatory menstrual cycle in 10 healthy women
(aged 18-40 years). Blood sampling and urinary collection was performed
every morning at 0800 h for 32 consecutive days. Every second day the
subjects were fasted overnight before blood sampling. Follicle stimulating
hormone, luteinizing hormone (LH), oestradiol, progesterone, IGF-I,
IGFBP-3, sex hormone-binding globulin, dihydroepiandrosterone sulphate and
GH were determined in all samples, whereas insulin and IGFBP-1 were
determined in fasted samples only. Serum IGF-I concentrations showed some
fluctuation during the menstrual cycle, with significantly higher values in
the luteal phase compared to the proliferative phase (P < 0.001). Mean
individual variation in IGF-I concentrations throughout the menstrual cycle
was 13.2% (SD 4.3; range 0.1-18.3%). There were no cyclic changes in
IGFBP-3 serum concentrations and no differences in IGFBP-3 concentrations
between the luteal and the proliferative phases. Mean individual variation
in IGFBP- 3 concentrations throughout the menstrual cycle was 8.8% (SD 2.7;
range 3.2-14.1). IGFBP-1 concentrations were inversely associated with
insulin concentrations, and showed a significant pre-ovulatory increase
that returned to baseline at the day of the LH surge. Fasting insulin
concentrations showed large fluctuations throughout the menstrual cycle
without any distinct cyclic pattern. No cyclic changes in urinary GH
excretion during menstrual cycle were detected. We conclude that, although
IGF-I concentrations are dependent on the phase of the menstrual cycle, the
variation in IGF-I concentrations throughout the menstrual cycle is
relatively small. Therefore, the menstrual cycle does not need to be
considered when evaluating IGF-I or IGFBP-3 serum values in women suspected
to have GH deficiency.
相似文献
766.
Samocha-Bone D; Lewin LM; Weissenberg R; Madgar Y; Soffer Y; Shochat L; Golan R 《Molecular human reproduction》1998,4(2):133-137
The process of sperm chromatin decondensation occurs when a spermatozoon
enters an ovum. Protamine disulphide bonds are reduced to SH and the
polycationic protamines combine with the polyanionic egg protein,
nucleoplasmin, thus being stripped from DNA which then combines with
histones. Defective chromatin decondensation will thus prevent further
development of the male pronucleus. In this study human sperm samples were
incubated in vitro at 28 degrees C (using a medium in which the polyanion,
heparin, substitutes for nucleoplasmin and beta- mercaptoethanol for egg
glutathione) for 10, 20 and 30 min before stopping the reaction with
formalin (to 3.6%). The DNA of the fixed cells was stained with Acridine
Orange by a one-step method and subjected to flow cytometry and data
analysis, in which a zone characteristic of condensed chromatin is outlined
on red-green fluorescence contour plots. After 20 min of incubation 97% of
the control spermatozoa that were in the mature window (WIN M) had
decondensed and moved out of this region. Defects in sperm decondensation
were seen in four semen samples of the 20 that were tested. In cases where
spermatozoa fail to produce a fertilized egg the cause may lie with
defective chromatin quality, including failure of the sperm chromatin to
decondense. The method described here is a simple procedure for detecting
sperm samples containing such defective cells.
相似文献
767.
768.
769.
A new pathogenic mutation in the APP gene (I716V) increases the relative proportion of A beta 42(43) 总被引:2,自引:0,他引:2
Eckman CB; Mehta ND; Crook R; Perez-tur J; Prihar G; Pfeiffer E; Graff- Radford N; Hinder P; Yager D; Zenk B; Refolo LM; Prada CM; Younkin SG; Hutton M; Hardy J 《Human molecular genetics》1997,6(12):2087-2089
We report a novel mutation in the amyloid precursor protein gene (APP
I716V) which probably leads to familial early onset Alzheimer's disease
with an onset age in the mid 50s. Cells transfected with cDNAs bearing this
mutation produce more A beta 1-42(43) than those transfected with wild-type
APP and this effect is additive with that of the previously reported APP
V717I mutation thus providing a novel approach for further increasing A
beta 1-42(43) in model systems.
相似文献
770.
Inhibition of delayed-type contact hypersensitivity in mice deficient in both E-selectin and P-selectin 总被引:11,自引:1,他引:11
Leukocyte rolling and emigration in response to inflammatory stimuli appears to involve both E-selectin- and P-selectin-dependent adhesion, which suggests that these molecules have overlapping functions. To clarify their relative contributions in chronic inflammation, we examined delayed-type contact hypersensitivity (DTH) responses in P- selectin, E-selectin, and E-/P-selectin-deficient mice. Oxazolone- induced increases in ear thickness and ear weight were equivalent in wild-type mice and in P-selectin and E-selectin mutants, but were significantly reduced in E-/P-selectin mutants. The number and area of microabscesses on the ears of E-/P-deficient mice were decreased by 72% and 93%, and the number of leukocytes invading the subdermal ear tissue was reduced. T cells from E-/P-deficient mice transferred oxazolone reactivity into naive wild-type mice. However, when donor T cells from wild-type mice were transferred into E-/P-selectin-deficient mice, the DTH response was significantly impaired. These results show that leukocyte recruitment into a subacute inflammatory reaction can occur when either P-selectin or E-selectin is present, but is significantly reduced when both selectins are absent. Both P- and E-selectin are likely to play important roles in the development and maintenance of inflammatory diseases. 相似文献