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991.
Congenital epidermoid splenic cysts are very rare. They are known to become symptomatic as a consequence of enlargement, hemorrhage, rupture, or infection. Recent options in the treatment of splenic cysts have included percutaneous drainage, partial splenectomy, or open splenic cystectomy. The authors present the first report of a pediatric patient with a large epidermoid cyst of the spleen treated by laparoscopic partial cyst excision and omental packing. Follow-up at 1 year confirms no recurrence. Laparoscopy provides a minimal access method of obtaining pathological confirmation of diagnosis, reduction of cyst complications, and a short hospital stay, while preserving splenic function. 相似文献
992.
Fluctuation analysis allows for the determination of mutation rates in cell cultures in vitro. As originally described by Luria and Delbruck and extended by Lea and Coulson and by Capizzi and Jameson, this analysis has been useful in estimating mutation rates in cultured cells where the frequency of mutational events is low. However. in cultures where high mutation rates and multiple independent mutation events occur, leading to the accumulation of many mutant cells, these standard methods may not apply. Here, we present a new method for the estimation of mutation rates based on the assumption that multiple events may contribute to the accumulation of mutant cells. We compared mutation rates determined by Lea and Coulson's and by Capizzi and Jameson's methods with those determined by our method using experimental and stimulated data from our studies of immunoglobulin gene mutation and isotype switching in B lymphocyte cultures. The three methods resulted in very different calculated rates when many mutants were present in the culture, such as when mutation rates were high, while only small differences in calculated rates were found when mutants were rare. Unlike previous fluctuation analysis calculations, our method is applicable for the estimation of both low and high rates. 相似文献
993.
994.
Because CD1-restricted T cells lack CD4 but produce IFN-gamma in response to nonpeptide mycobacterial antigens, they could play a unique role in immunity to tuberculosis. We studied CD1-restricted T cells in the context of HIV infection by expanding CD4(-) T cell lines from 10 HIV-infected patients. Upon stimulation with Mycobacterium tuberculosis antigen or upon exposure to macrophages infected with M. tuberculosis, these T cell lines proliferated, produced IFN-gamma, and showed cytolytic T cell (CTL) activity against macrophages pulsed with mycobacterial antigen, findings consistent with a protective role against M. tuberculosis. Anti-CD1b antibodies abrogated T cell proliferation, IFN-gamma production, and CTL activity, demonstrating that these T cells are CD1 restricted. IFN-gamma production in response to M. tuberculosis was enhanced by antitransforming growth factor-beta in 8/10 lines, and by IL-15 in 2/10 lines. IFN-gamma production was augmented in a nonantigen-specific manner by IL-12 in 4/8 lines. When live HIV was cocultured with CD1-restricted T cell lines, p24 antigen and proviral DNA were not detected, indicating that the T cells were not infectable with HIV. Vaccination strategies aimed at activation and expansion of M. tuberculosis-reactive CD1-restricted T cells in HIV-infected patients may constitute a novel means to provide protection against tuberculosis, while minimizing the risk of enhancing HIV replication through stimulation of CD4(+) cells. 相似文献
995.
996.
D-Glucal and a series of substituted derivatives have been tested as substrates, inhibitors and inactivators of the Agrobacterium faecalis beta-glucosidase in order to probe structure/function relationships in this enzyme. D-Glucal is shown to be a substrate (kcat = 2.3 min-1, Km = 0.85 mM) undergoing hydration with stereospecific protonation from the alpha-face to yield 2-deoxy-beta-D-glucose. 1-Methyl-D-glucal surprisingly serves as only a poor substrate (kcat = 0.056 min-1, Km = 57 mM), also undergoing protonation from the alpha-face. 2-Fluoro-D-glucal, however is completely inert, as a result of inductive destabilisation of the oxocarbenium ion-like transition state for protonation, and functions only as a relatively weak (Ki = 24 mM) inhibitor. Similar behaviour was seen with almond beta-glucosidase and yeast alpha-glucosidase and for the interaction of 2-fluoro-D-galactal with Escherichia coli beta-galactosidase. A series of of alpha, beta-unsaturated glucal derivatives was also synthesised and tested as potential substrates, inhibitors or inactivators of A. faecalis beta-glucosidase. Of these only 1-nitro-D-glucal functioned as a time dependent, irreversible inactivator (ki = 0.011 min-1, Ki = 5.5 mM), presumably acting as a Michael acceptor. Electrospray mass spectrometric analysis revealed multiple labeling of the enzyme by this inactivator, lessening its usefulness as an affinity label. Less reactive Michael acceptor glycals which might have been more specific (1-cyano-, 2-cyano-, 1-carboxylic acid, 1-carboxylic acid methyl ester) unfortunately did not function as inactivators or substrates, only as relatively weak reversible inhibitors (Ki = 3-96 mM). 相似文献
997.
998.
DB Nelson RB Ness JF Peipert DE Soper AJ Amortegui J Gluck H Wiesenfeld PA Rice 《Canadian Metallurgical Quarterly》1998,7(8):1033-1040
We sought to identify factors that discriminate between women with a lower genital tract infection and women with a lower genital tract infection and endometritis. This study enrolled women at risk for or having a lower genital tract infection with Chlamydia trachomatis or Neisseria gonorrhoeae and measured behavioral and clinical factors. Women were identified through contact tracing of male partners, presentation with cervicitis, or presentation with symptoms of pelvic inflammatory disease and classified as (1) having a lower genital tract infection without endometritis, (2) having a lower genital tract infection with endometritis, (3) having no lower genital tract infection with endometritis, and (4) having neither a lower genital tract infection nor endometritis. The primary comparison was between women having a lower genital tract infection without endometritis to women having a lower genital tract infection and endometritis. Women with a lower genital tract infection and endometritis were older and reported a history of more sexually transmitted diseases (70.0% vs. 56.7%), abdominal pain (82.2% vs. 60.0%), and use of barrier methods of contraception (28.9% vs. 8.6%) than women with a lower genital tract infection alone. The regression model found that women with a lower genital tract infection and endometritis were 7.1 times (95% CI = 2.2-23.0) more likely to report abdominal pain and 4.6 times (95% CI = 1.5-14.9) more likely to use barrier methods of contraception than women with a lower genital tract infection alone. These results suggest that behavioral factors, in addition to symptoms, can be used to identify women with and without upper genital tract involvement. 相似文献
999.
PA Burghaus BT Wellde T Hall RL Richards AF Egan EM Riley WR Ballou AA Holder 《Canadian Metallurgical Quarterly》1996,64(9):3614-3619
Merozoite surface protein 1 (MSP-1) of Plasmodium falciparum is an antimalarial vaccine candidate. The highly conserved 19-kDa C-terminal processing fragment of MSP-1 (MSP-1(19)) is of particular interest since it contains epitopes recognized by monoclonal antibodies which inhibit the invasion of erythrocytes in vitro. The presence of naturally acquired anti-MSP-1(19) antibodies in individuals exposed to malaria has been correlated with reduced morbidity, and immunization with an equivalent recombinant P. yoelii antigen induces substantial protection against this parasite in mice. We have expressed P. falciparum MSP-1(19) in Escherichia coli as a correctly folded protein and immunized Aotus nancymai monkeys by using the protein incorporated into liposomes and adsorbed to alum. After vaccination, the sera from these animals contained anti-MSP-1(19) antibodies, some of which competed for binding to MSP-1(19) with monoclonal antibodies that inhibit parasite invasion of erythrocytes in vitro. However, after challenge with either a homologous or a heterologous strain of parasite, all animals became parasitemic and required treatment. The immunization did not induce protection in this animal model. 相似文献
1000.