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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
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Survival of hepatitis A virus on human hands and its transfer on contact with animate and inanimate surfaces. 总被引:12,自引:0,他引:12 下载免费PDF全文
J N Mbithi V S Springthorpe J R Boulet S A Sattar 《Journal of clinical microbiology》1992,30(4):757-763
The survival of hepatitis A virus (HAV; strain HM175) on the hands of five volunteers was determined by depositing 10 microliters of fecally suspended virus on each fingerpad and eluting the inoculum after 0, 20, 60, 120, 180, and 240 min. The amount of virus recovered from each fingerpad at 0 min was approximately 6.0 x 10(4) PFU. At the end of 4 h, 16 to 30% of the initially recoverable virus remained detectable on the fingerpads. HAV inocula (10 microliters; approximately 1.0 x 10(4) PFU) placed on fingerpads or 1-cm-diameter metal disks were used to determine virus transfer to clean surfaces upon a 10-s contact at a pressure of nearly 0.2 kg/cm2. When the inoculum was dried for 20 min, virus transfer from fingerpad to fingerpad, fingerpad to disk, and disk to fingerpad ranged from 2,667 to 3,484 PFU, while 0 to 50 PFU could be transferred after 4 h of drying. Elevation of the contact pressure alone from 0.2 to 1.0 kg/cm2 resulted in an approximately threefold increase in the amount of virus transferred. Incorporation of friction (10 half turns of the finger during 10 s of contact) with the low and high levels of pressure gave two- and threefold increases in the PFU of virus transferred, respectively. Pressure and friction were found to significantly affect HAV transfer (F = 33.98; P less than 0.05), irrespective of the mode of transfer used. No statistically significant interaction was observed between mode of transfer and pressure or friction. The findings of this quantitative study suggest that human hands may play an important role in the direct as well as the indirect spread of HAV. 相似文献
6.
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
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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
9.
Mohammad Abdus Salam Naoko Matsumoto Khairul Matin Yuzo Tsuha Ryoma Nakao Nobuhiro Hanada Hidenobu Senpuku 《Clinical and Vaccine Immunology : CVI》2004,11(2):379-386
An oral biofilm is a community of surface-attached microorganisms that coats the oral cavity, including the teeth, and provides a protective reservoir for oral microbial pathogens, which are the primary cause of persistent and chronic infectious diseases in patients with dry mouth or Sjögren''s syndrome (SS). The purpose of this study was to establish an animal model for studying the initial adhesion of oral streptococci that cause biofilm formation in patients with dry mouth and SS in an attempt to decrease the influence of cariogenic organisms and their substrates. In nonobese diabetogenic (NOD) mice that spontaneously develop insulin-dependent diabetes mellitus (IDDM) and SS, we replaced major histocompatibility complex (MHC) class II (Ag7 Eg7) and class I Db with MHC class II (Ad Ed) and class I Dd from nondiabetic B10.D2 mice to produce an animal model that inhibited IDDM without affecting SS. The adhesion of oral streptococci, including Streptococcus mutans, onto tooth surfaces was then investigated and quantified in homologous recombinant N5 (NOD.B10.D2) and N9 (NOD.B10.D2) mice. We found that a higher number of oral streptococci adhered to the tooth surfaces of N5 (NOD.B10.D2) and N9 (NOD.B10.D2) mice than to those of the control C57BL/6 and B10.D2 mice. On the basis of our observation, we concluded that these mouse models might be useful as animal models of dry mouth and SS for in vivo biological studies of oral biofilm formation on the tooth surfaces.Oral streptococci are present in large numbers in dental plaque, and several types interact with the enamel salivary pellicle to form a biofilm on tooth surfaces (9, 16, 17, 21, 29). Streptococci account for approximately 20% of the total number of salivary bacteria (24), with Streptococcus salivarius being the primary organism. Further, the densities of Streptococcus mutans and Streptococcus sanguis in saliva are more than 1 × 105 cells per ml. S. mutans is a pioneering organism that plays an important role in biofilm formation on tooth surfaces and is a primary causative agent of dental caries (9, 16, 21). The mechanical forces of salivary flow and tongue movement tend to dislodge and expel bacteria from tooth surfaces and the oral cavity (3, 5, 6), and their importance in controlling microbial colonization in the oral cavity has been well demonstrated in individuals with diabetes mellitus, Sjögren''s syndrome (SS), and dry mouth, who suffer from a rapid overgrowth of biofilm and rampant caries, making them highly susceptible to oral infections (1-2, 6). Thus, attempts to investigate the initial adhesion by oral streptococci, including S. mutans, in mouse models are likely to aid in the understanding and prevention of oral infectious diseases caused by the components of oral biofilm.Previous studies of S. mutans infections in the oral cavities of mice have been performed by feeding the animals diets containing sucrose in the presence of glucans (13, 15, 30, 43). Since the adherence of S. mutans to the tooth surface may depend on the balance between physical adherence and synthesis of insoluble glucans in a natural environment, that infection method may be inappropriate for investigation of natural biofilm formation associated with streptococci, including S. mutans (18, 39).The nonobese diabetogenic (NOD) mouse strain is currently the best available model for the study of insulin-dependent type 1 diabetes mellitus (IDDM) and SS (11, 31), both of which develop spontaneously and are characterized by lymphatic infiltration of the pancreas and salivary glands. Oral changes are prominent features of these diseases, which are manifested by dry mouth and hyposalivation (6, 7, 37). NOD mice are also used as an animal model for the study of oral infectious diseases associated with systemic diseases such as diabetes and SS or dry mouth.The unique major histocompatibility complex (MHC) class II genes (I-Ag7, no expression of I-E) represent dominant susceptibility factors and mediate activated T cells during the development of diabetes in NOD mice (11, 22, 25, 36, 41, 42). In the NOD model of SS, histopathological analyses of the salivary glands in MHC-congenic strains of NOD mice have indicated that the I-Ag7 region is not required for lymphocytic infiltration (26, 31). Further, replacement of the NOD MHC class I Kd region with another haplotype, MHC class I Kwm7, as well as replacement of the MHC class II Ag7 Eg7 and class I Dd regions with the corresponding region from the other MHC haplotype, has been shown to prevent diabetes (12). However, replacement with MHC class I K does not completely prevent development of insulitis. In another report, NOD mice pretreated nasally by using peptides restricted with MHC class I Kd showed a delayed onset of spontaneous IDDM, though insulitis could not be prevented by the induction of tolerance (23).In the present study, we attempted to establish an animal model for oral infectious diseases such as dental caries by focusing on replacement of the MHC class II and class I D region but not the class I K region in nondiabetic NOD mice by outcrossing B10.D2 mice (Kd, I-Ad, and Dd) with NOD mice (Kd, I-Ag7, and Db) because the MHC class I K region in B10.D2 mice is identical with that in NOD mice (12). The present backcrossed and intercrossed NOD mice with the MHC class II and MHC class I D region replaced with that from B10.D2 mice developed SS, however, not diabetes. We then attempted to determine whether these mice would be useful as animal models for a sucrose-free study of the initial adhesion of oral streptococci on tooth surfaces in humans. 相似文献
10.
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.
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