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排序方式: 共有1222条查询结果,搜索用时 0 毫秒
1.
2.
M. E. McNerney K.-M. Lee P. Zhou L. Molinero M. Mashayekhi D. Guzior H. Sattar S. Kuppireddi C.-R. Wang V. Kumar M.-L. Alegre 《American journal of transplantation》2006,6(3):505-513
To achieve donor-specific immune tolerance to allogeneic organ transplants, it is imperative to understand the cell types involved in acute allograft rejection. In wild-type mice, CD4(+) T cells are necessary and sufficient for acute rejection of cardiac allografts. However, when T-cell responses are suboptimal, such as in mice treated with costimulation-targeting agents or in CD28-deficient mice, and perhaps in transplanted patients taking immunosuppressive drugs, the participation of other lymphocytes such as CD8(+) T cells and NK1.1(+) cells becomes apparent. We found that host NK but not NKT cells were required for cardiac rejection. Ly49G2(+) NK cells suppressed rejection, whereas a subset of NK cells lacking inhibitory Ly49 receptors for donor MHC class I molecules was sufficient to promote rejection. Notably, rejection was independent of the activating receptors Ly49D and NKG2D. Finally, our experiments supported a mechanism by which NK cells promote expansion and effector function of alloreactive T cells. Thus, therapies aimed at specific subsets of NK cells may facilitate transplantation tolerance in settings of impaired T-cell function. 相似文献
3.
J. Hilton R.J. Dearman N. Sattar D.A. Basketter I. Kimber 《Food and chemical toxicology》1997,35(12):1209-1218
Whereas many foreign proteins are immunogenic, only a proportion is also allergenic, having the capacity to induce the quality of immune response necessary to support the production of IgE antibody. We have demonstrated previously that intraperitoneal administration to mice of proteins such as ovalbumin (OVA) or the industrial enzyme A. oryzae lipase, which possess significant allergenic potential, stimulates the production of both IgG and IgE antibody. Identical exposure to bovine serum albumin (BSA), a protein with limited potential to cause immediate respiratory or gastrointestinal hypersensitivity reactions, induced IgG responses only. In the current investigations, the quality of immune responses induced following exposure to these proteins via mucosal tissue (intranasal) has been compared with those provoked following administration via a non-mucosal (intraperitoneal) route of exposure. Intranasal or intraperitoneal administration of BSA, OVA or A. oryzae lipase elicited in each case vigorous IgG and IgG1 antibody responses. For all three proteins, at every concentration tested, and via both routes of exposure, IgG1 antibody titres paralleled closely IgG titres. However, the three materials displayed a differential potential to provoke IgE responses and this correlated with their known allergenic potential in humans. Thus, OVA and A. oryzae lipase stimulated strong IgE antibody responses, whereas BSA provoked low titre IgE only at the highest concentration tested (5% administered intraperitoneally). The quality of induced responses was not affected by the route of exposure. It would appear, therefore, that the stimulation of IgG and IgG1 antibody responses is a reflection of protein immunogenicity whereas protein allergenicity is associated with the induction of strong IgE responses. 相似文献
4.
5.
de Boer A; Schroder C; Reddingius R; Willems H; Monnens L 《Nephrology, dialysis, transplantation》1998,13(9):2348-2350
Background: The passage of proteins across the
glomerular filtration barrier is mainly determined by the size of the
protein. In nephrotic syndrome (NS) the glomerular permselectivity is
affected, causing proteinuria. Some authors suggest the existence of a
generalized basement membrane defect. The permeability characteristics of
the peritoneal basement membrane in children with NS are not known.
Methods: The transperitoneal transport of proteins
with a different molecular weight ({beta}2-microglobulin MW 11 800 D,
albumin MW 69 000 D, IgG MW 160 000 D, and &agr;2-macroglobulin MW 820
000 D) was studied in a study group (group A) consisting of six stable
nephrotic children (three with glomerulosclerosis and three with congenital
nephrotic syndrome, one of them with mesangial sclerosis) and compared to a
control group (group B) consisting of eight stable children on peritoneal
dialysis. After a dwell of 6 h with Dianeal 1.36% dialysate and serum
samples were collected. For each patient the dialysate to plasma (D/P)
ratio of the four proteins were calculated. The D/P ratios of the nephrotic
patients in group A were compared to the D/P ratios of the patients in the
control group B. Data were expressed as mean ±SD.
Results: The values for the D/P ratios (in percentage)
of {beta}2-microglobulin, albumin, IgG and &agr;2-macroglobulin in
group A were 19.6±9.9, 2.7±1.7, 1.6±0.9,
and 0.5±0.4, compared to 24.9±10.2,
4.0±2.3, 2.2±1.2, and 0.7±0.3 in the
control group B. The ratios were plotted against MW on a double logarithmic
scale. In all patients a linear relationship between molecular weight and
D/P ratio of the proteins was obtained. The D/P ratios of the study group
did no differ significantly from the control group.
Conclusion: We conclude that the size selectivity of
the capillary permeability is not affected in the peritoneal membrane in
children with NS due to glomerulosclerosis and congenital nephrotic
syndrome. 相似文献
6.
W. Ken Busfield Ian M. G. Cowie M. A. Sattar Mondal 《Macromolecular chemistry and physics.》1979,180(7):1775-1786
Two series of block copolymers have been synthesized comprising of soft polytrifluoroacetaldehyde (polyacetal) segments and of hard 4,4′-methylenedi(phenyl isocyanate)/cis-cyclohexane-1,4-diol polyurethane segments. The series-A copolymers in which the soft segments were directly bound to the hard segments had significantly lower thermal stability than the series-B copolymers in which the soft segments were linked to the hard segments by sebacic ester units. In both series the thermal stability decreased with increasing soft segment content. The series-A copolymers exhibited two thermal transitions both characteristic of Tg's and separated by about 60 K. In contrast the series-B copolymers exhibited two characteristic Tg's separated by 200–250 K, depending on composition, together with an additional endothermic transition at about ambient temperature. All transitions for both series decreased with increasing soft segment content. The observations have been compared with those of other polyether and polyester based polyurethanes. 相似文献
7.
Schmid KW Bankfalvi A Mucke S Ofner D Riehemann K Schroder S Stucker A Totsch M Dockhorn-Dworniczak B 《Endocrine pathology》1996,7(2):121-130
Routinely processed tissues from a series of benign and malignant thyroid lesions were immunohistochemically investigated
with antibodies against p53 and mdm-2. p53 was immunolocalized in <10% of nuclei in 2/80 nodular goiters, 2/60 follicular
adenomas, 26/68 follicular carcinomas, 7/40 papillary carcinomas, 3/10 “insular” carcinomas, and 10/31 anaplastic carcinomas.
More than 10% positively stained nuclei were found in 2 widely invasive follicular, 2 insular, and 15 anaplastic carcinomas.
All p53-positive cases showed a concomitant immunohistochemical mdm-2 expression; an immunohistochemical colocalization on
serial section was demonstrated in 12 anaplastic carcinomas. Screening by polymerase chain reaction single-strand conformation
polymorphism (PCR-SSCP) analysis of these 12 cases revealed no relevant mutations in the coding regions of exons 2–11 of the
p53 gene. Additionally, 1 follicular adenoma, 6 follicular carcinomas (4 minimally and 2 widely invasive), 1 papillary, and
2 poorly differentiated insular carcinomas were mdm-2 positive without immunohistochemically detectable p53 expression. These
results provide evidence that wild-type p53 expression in thyroid carcinomas may be associated with mdm-2 induced formation
of stable complexes. However, the role of p53 mutations and p53 protein inactivation owing to other factors (e.g., mdm-2)
in the progression of thyroid carcinomas is still poorly understood. 相似文献
8.
This study examined the effects of anonymity, gender, and erotophilia on the quality of self-reports of socially sensitive health-related behaviors. A sample of 155 male and 203 female undergraduate students was randomly assigned to an anonymous and a confidential (i.e., nonanonymous) assessment condition. Gender, erotophilia, self-reports (of substance use, sexual behaviors, illegal activity), and perceived item threat were assessed by questionnaire. Data quality was strongly affected by experimental condition and gender. Thus, terminations were more frequent in the confidential condition and among women. In the confidential condition, women were significantly more likely to prefer not to respond to sensitive items compared to men. Both female gender and confidential condition were associated with lower frequency reports of sensitive health behaviors, and greater perceived threat of the assessment questions. Self-reported engagement in sensitive behaviors was positively related to both perceived question threat and erotophilia. Path analyses suggest that question threat mediates the effects of anonymity manipulations and gender on data quality (item refusal, termination), and that erotophilia mediates the effects of gender on incidence and frequency self-reports. The results indicate that anonymous assessments as well as male gender are associated with better data quality. 相似文献
9.
Uterine myomata and outcome of assisted reproduction 总被引:5,自引:8,他引:5
Ramzy AM; Sattar M; Amin Y; Mansour RT; Serour GI; Aboulghar MA 《Human reproduction (Oxford, England)》1998,13(1):198-202
The aim of this work was to study the effect of uterine myomata on the
implantation rate and outcome in in-vitro fertilization (IVF) and
intracytoplasmic sperm injection (ICSI). Among 406 patients, 51 (12.6%)
were found to have uterine corporeal myomata. Twelve patients were excluded
from the study as they had large myomata, submucous myomata or intramural
myomata encroaching on the cavity. These patients were advised to have
myomectomy before being enrolled in the IVF/ICSI programme. The remaining
patients (n = 39) were sorted according to the number, site and size of the
myomata as assessed by transvaginal sonography. Three patients had more
than one myoma. Most of the myomata were subserous (72.7%) and the mean
diameter of the myomata was 3.5 +/- 0.9 cm. A control group (n = 367) was
chosen with normal uteri and no history of uterine reconstruction surgery.
The mean age of myoma patients was 34.7 +/- 3.6 years as compared to 34.0
+/- 4.4 years in the control group. The age, period of infertility, body
mass index, duration and number of human menopausal gonadotrophin ampoules
needed for stimulation, oestradiol levels, number of oocytes retrieved and
the fertilization rate were not significantly different in the myoma
patients compared to the control group. Fifteen myoma patients (38.5%)
subsequently showed one or more pregnancy sacs on ultrasonography of which
three (20%) spontaneously aborted during the first trimester and two
(13.3%) had preterm labour, as compared to 123 (33.5%), 19 (15.5%) and nine
(7.3%) respectively, among the control group (P = 0.27, 0.33 and 0.21). In
conclusion, uterine corporeal myomata, not encroaching on the cavity and
<7 cm in mean diameter, do not affect the implantation or miscarriage
rates in IVF or ICSI.
相似文献
10.
Rotavirus survival on human hands and transfer of infectious virus to animate and nonporous inanimate surfaces. 总被引:9,自引:3,他引:9 下载免费PDF全文
S A Ansari S A Sattar V S Springthorpe G A Wells W Tostowaryk 《Journal of clinical microbiology》1988,26(8):1513-1518
We tested the survival of the Wa strain of human rotavirus on the hands of volunteers and also studied infectious virus transfer between animate and inanimate (stainless steel disks) surfaces. The virus was diluted in a 10% suspension of feces, and 10 microliters (1 X 10(3) to 4 X 10(4) PFU) was placed on each of the four fingerpads of the left hand. One milliliter of 20% tryptose phosphate broth in Earle balanced salt solution was used for virus elution from each fingerpad, and the hands were disinfected with 70% ethanol before they were washed with an antiseptic soap and water. At 20, 60, and 260 min after inoculation, approximately 57, 43, and 7%, respectively, of the input infectious virus could be recovered. For virus transfer, the inoculum (2 X 10(4) to 8 X 10(4) PFU) was allowed to dry, and the donor surface was kept in contact with the recipient surface for 10 s at a pressure of approximately 1 kg/cm2. At 20 and 60 min after virus inoculation, 16.1 and 1.8%, respectively, of the input infectious virus could be transferred from the contaminated hand to a clean disk; when a clean hand was pressed against a contaminated disk, virus transfer was 16.8 and 1.6%, respectively. Contact between a contaminated and a clean hand 20 and 60 min after virus inoculation resulted in the transfer of 6.6 and 2.8%, respectively, of the input infectious virus. These findings indicate the potential vehicular role for human hands in the spread of rotaviral infections. 相似文献