Natural killer cell precursors in the CD44neg/dim T-cell receptor population of mouse bone marrow

Natural killer (NK) cells develop from the nonadherent cell component of NK long-term bone marrow (BM) cultures (NK-LTBMC). Because these nonadherent cells are depleted of mature NK cells and T cells, but appear to enriched for NK precursors, they were used as a starting population to begin to define the NK precursors that function in NK- LTBMC. As the stromal cell component of NK-LTBMC has been shown to support interleukin (IL)-2-induced, CD44 dependent, NK cell development from nonadherent NK precursors, NK-LTBMC stroma was used in a limiting dilution assay (LDA) to quantitate the precursors. NK-LTBMC in 96-well plates were irradiated (20 Gy) to kill hematopoietic cells (including the NK precursors), seeded with limiting dilutions of the cells to be quantitated, cultured with 500 U/mL IL-2 for 13 days and assayed for development of NK activity by adding 51Cr-labeled YAC-1 cells to the wells and evaluating the release of 51Cr after 4 hours. Flow cytometric analysis, sorting, and quantitation of the nonadherent cell component of NK-LTBMC showed that NK precursors were concentrated in the CD44neg/dim subset that comprised 10% of the "lymphoid" gated cells. When the CD44neg/dim subset was sorted from BM of mice treated with 5- fluorouracil (5-FU) day before (-1FUBM), there were about 30% T cells, but no NK-1.1+ cells. When the T cells were removed by sorting and the CD44neg/dim, alphabeta, gammadelta T-cell receptorneg (TCR-) subpopulation was seeded onto irradiated stroma with IL-2, they proliferated, developed NK activity, became NK-1.1+ and CD44bright and remained alphabeta, gammadelta TCR-. The frequency of NK precursors in this population as estimated from the LDA was about 1/500.     

Platelet glycoproteins IIb and IIIa associated with blood monocytes are derived from platelets

Platelet glycoprotein IIb/IIIa (GP IIb/IIIa), the receptor complex for fibrinogen, has been regarded as a megakaryocyte/platelet lineage- restricted antigen. Recently, however, it has been reported that GP IIb/IIIa is expressed in blood monocytes. Studies were performed to establish the origin and immunological characteristics of monocyte- associated glycoproteins IIb and IIIa (GPs IIb and IIIa). Preparations of blood monocytes containing varying platelet-monocyte ratios were metabolically labeled with [35S]methionine with the expectation that any newly synthesized GPs IIb and IIIa would be monocyte-derived, since platelets have only rudimentary protein synthetic apparatuses. Analyses of sodium dodecyl sulfate (SDS) gels of homogenates of cell preparations containing from 200 to 5:1 platelet-monocyte ratios revealed that unlabeled GPs IIb and IIIa were readily immunoisolated using protein A-Sepharose immunobeads. However, fluorographic analyses of the same cell preparations pulse-labeled with [35S]methionine failed to demonstrate synthesis of GP IIb or IIIa. Additionally, no GP IIb or IIIa was detected when immunoisolation was carried out in pure preparations of monocytes containing less than 1:100 platelet-monocyte ratios and SDS acrylamide gels were stained by the sensitive silver stain method. Furthermore, heterologous polyspecific antisera and two monoclonal antibody preparations against GPs IIb and IIIa, which bound to platelets, failed to bind to monocyte membranes. Thus, evidence was presented that indicated that monocytes do not synthesize platelet GPs IIb and IIIa and that detection of these molecules in blood monocyte preparations reflects platelet contamination.     

Protein C deficiency resulting from possible double heterozygosity and its response to danazol

A unique family with protein C (PC) deficiency is described. The proband had a history of renal vein thrombosis as a newborn and iliofemoral thrombosis at the age of 6 years. After 6 months of heparin treatment, discontinuation of anticoagulation therapy was accompanied by persistent hypofibrinogenemia with increased fibrinogen consumption. With continuous infusion of heparin, fibrinogen turnover normalized, and the child has remained free of thrombosis. Both the immunologic level of PC and the functional activity measured by amidolytic assay were moderately reduced (47% and 34%, respectively). Functional activity of PC measured by its anticoagulant activity was disproportionately lower (14%). A 3-year-old asymptomatic sibling had a similar disproportionate reduction of PC anticoagulant activity compared with the amidolytic activity or immunologic level. The mother demonstrated type I PC deficiency with a proportionate reduction in immunologic protein levels (59%), anticoagulant activity (52%), and amidolytic activity (46%), whereas the father had type II PC deficiency with normal immunologic protein levels (102%), normal amidolytic function (98%), but a low anticoagulant function (50%). An abnormal PC molecule was detected by two-dimensional immunoelectrophoresis in the father and two children. These data are consistent with the hypothesis that the children are doubly heterozygous for two different types of PC deficiency inherited from each of the parents. A 14-day trial of danazol in the proband resulted in a rise in the PC antigen concentration from 66% to 98% but no change in PC anticoagulant function.     

Lymphadenopathy-associated virus antibodies and T cells in hemophiliacs treated with cryoprecipitate or concentrate

Evidence for exposure to lymphadenopathy-associated virus (LAV) was investigated in 48 patients with hemophilia, 15 of whom had been treated exclusively with single-donor cryoprecipitate. The prevalence of antibodies to LAV in all patients was 53% in 1983 and 63% in 1984, while in patients treated only with cryoprecipitate, the prevalence was 31% in 1983 and 40% in 1984. Patients treated with any concentrate had a seroprevalence of 65% in 1983 and 77% in 1984. Seropositive patients were more likely to have a significant reduction in the ratio of helper to suppressor T cells, absolute numbers of helper T cells, and T cell function in vitro. Seven of 18 patients who were seronegative in 1983 had seroconverted by 1984. The relative risk of seroconversion for patients using any concentrate since 1981 compared with those using cryoprecipitate only was 3.9 (P = .04). Nevertheless, the rate of conversion in the latter group was 18% per year.     

Effect of recombinant human interleukin-6 (rhIL-6) and rhIL-3 on hematopoietic regeneration as demonstrated in a nonhuman primate chemotherapy model

Using a recently developed hepsulfam-induced pancytopenia model in rhesus macaques, we have studied the effects of recombinant human interleukin-6 (rhIL-6) and rhIL-3 on marrow regeneration. Control animals were given hepsulfam (1.5 g/m2 by a single 30-minute intravenous [i.v.] injection, n = 4), while study animals received hepsulfam followed by rhIL-6, rhIL-3, or a combination of rhIL-6 and rhIL-3 (n = 3 per study group). Each cytokine was administered by once- daily subcutaneous (SC) injection (15 micrograms/kg/d) for 3 weeks beginning the day after chemotherapy (days 2 through 22). Mean platelet counts in control animals were < 100,000/microL on days 15 through 24, with 50% of the counts < 50,000/microL and two of four animals requiring platelet transfusion. In the rhIL-6- and rhIL-6/rhIL-3- treated groups, the nadir mean platelet counts were 164,000 +/- 58,700/microL and 162,300 +/- 23,800/microL, respectively, and occurred on day 15. Platelet counts in the rhIL-3-treated group were similar to those in controls. Mean absolute neutrophil counts (ANCs) < 1,000/microL occurred on days 10 through 29 in control animals, days 8 through 15 in rhIL-6-treated animals, and days 6 through 8 and 13 in rhIL-6/rhIL-3-treated animals. The frequency of ANCs < 500/microL was significantly less in the rhIL-6- and rhIL-6/rhIL-3-treated groups versus control groups (2.7 +/- 0.6 and 2.0 +/- 1.0 vs 7.0 +/- 1.4 occurrences, respectively; P < .05). rhIL-3-treated animals had ANCs similar to those in controls; one animal died with septicemia on day 21. Monkeys receiving rhIL-6 were significantly more anemic during the cytokine administration period; however, the anemia resolved by day 24. Coadministration of rhIL-3 and rhIL-6 partially corrected the anemia. The data indicate that rhIL-6 prevents significant thrombocytopenia and shortens the neutropenic period in this chemotherapy model.     

美国教学医院教师专业发展的全国性调查

在当前医学教育持续变革的背景中,医学教师的专业发展成为广泛关注的焦点.为了解目前美国以提高教师的教学技能为目标的教师专业发展(faculty development,FD)活动的参与率、课程设计、教学方法和评估策略等情况,美国约翰·霍普金斯大学预防、流行病学和临床研究中心采取邮件调查的方式,对美国277家教学医院进行了调查.     

Musculoskeletal neoplasms after intraarterial chemotherapy: correlation of MR images with pathologic specimens

The most accurate prognostic indicator in patients with musculoskeletal sarcomas is the percentage of tumor necrosis after intraarterial chemotherapy. Magnetic resonance (MR) imaging was evaluated to determine its ability to indicate the percentage of necrosis in musculoskeletal neoplasms after treatment. Fourteen patients with musculoskeletal neoplasms underwent treatment protocols including intraarterial chemotherapy (n = 14), radiation therapy (n = 6), and systemic chemotherapy (n = 14). All patients underwent MR imaging before and after treatment, and all underwent either limb salvage surgery (n = 8) or amputation (n = 6) within 1 week of the last MR examination. Standard unehanced spin-echo T1-, spin-density-, and T2-weighted MR sequences were used. The MR images were compared with the pathologic specimens. On T2-weighted images, the signal intensities of viable tumor, tumor necrosis, edema, hemorrhage, and necrosis overlapped. With the unenhanced spin-echo technique, MR imaging cannot be used to predict the percentage of tumor necrosis in musculoskeletal neoplasms after intraarterial chemotherapy.     

低氧训练对下丘脑-垂体-肾上腺皮质轴内分泌相关激素的影响

目的:总结低氧训练对下丘脑-垂体-肾上腺皮质轴内分泌相关激素的影响,为科学运动训练提供依据。资料来源:应用计算机检索中国期刊全文数据库1994-01/2006-10的相关文章,检索词"低氧,低氧训练,下丘脑-垂体-肾上腺,激素",并限定文章语言种类为中文。并应用计算机检索美国国立医学图书馆NCBI1980-01/2006-10的相关文章,检索词"Hypoxic Training,organism endocrine system,hormone",并限定文章语言种类为English。资料选择:对资料进行初审,选取低氧训练与下丘脑-垂体-肾上腺分泌的相关激素有关的文献,并作初步分类,同类文献首选近年发表的核心期刊文章。排除重复及综述类文献。资料提炼:共收集到95篇相关文章,其中56篇属于重复及综述类文献,对符合标准38篇文献进行分析整理。资料综合:①高海拔状态下机体对低氧产生应激反应,表现为下丘脑-垂体-肾上腺皮质轴的适应性运转,血中促肾上腺皮质激素浓度增加,以调节机体对应激刺激的适应能力,同时使促肾上腺皮质激素释放因子分泌增加。②高原训练后,睾酮和皮质醇的变化都较明显,其总体变化均趋于降低,睾酮/皮质醇值有升有降,从一定意义上反映了机体的机能状况与疲劳积累程度。③低氧还引起大鼠血浆β-内啡肽浓度升高,可使心房钠尿素增加、前列腺素增加、血管内皮素分泌增加及抑制血管内皮舒张因子的分泌。结论:激素对机体的新陈代谢、生长发育、各种功能活动以及维持内环境稳态等方面发挥重要的调节作用,低氧训练对机体激素的影响一直应该受到人们的关注。     

Simultaneous confirmation and differentiation of human T-lymphotropic virus types I and II infection by modified western blot containing recombinant envelope glycoproteins

A modified Western blot (WB) that includes both shared (r21e) and unique recombinant envelope proteins from human T-lymphotropic virus (HTLV) type I (rgp46I) and type II (rgp46II) was compared to conventional HTLV serologic tests in 379 United States blood donors and individuals residing in diverse geographic regions, and the specimens were categorized as positive (n = 158), indeterminate (n = 158), or negative (n = 63) for HTLV infection. Of the 158 HTLV-I/II-positive specimens (66 requiring radioimmunoprecipitation assay [RIPA] for confirmation), 156 reacted concordantly with r21e, gag, and either rgp46I or rgp46II, thus eliminating the need for RIPA in all but two specimens and yielding a test sensitivity of 98.7 percent. Of the 158 indeterminate and 63 negative specimens, none reacted with r21e and rgp46I or rgp46II, yielding a test specificity of 100 percent. Furthermore, analysis of an additional 184 consecutive specimens from a retrovirology reference laboratory demonstrated that the modified WB correctly identified 27 of 28 HTLV-I specimens and all 13 HTLV-II specimens, with a test sensitivity of 97.6 percent. None of specimens that were indeterminate or nonreactive in conventional WB and/or RIPA and none of the screening enzyme immunoassay-negative specimens reacted with r21e and either rgp46I or rgp46II, for a test specificity of 100 percent. Thus, the modified WB appears to be highly sensitive and specific for simultaneous detection and discrimination of HTLV-I from HTLV-II and has the advantage of being a one-step assay that is easily performed in all types of laboratory settings and allows rapid, reliable, and standardized testing for HTLV-I/II infection.