Viability and functional integrity of washed platelets

The viability and functional integrity of saline- and ACD-saline-washed platelets were compared with those of unwashed platelets. After template bleeding time (TBT) was measured, 15 healthy volunteers underwent plateletpheresis and ingested 600 mg of aspirin. Autologous 111In-labeled platelets were transfused: unwashed (n = 5), washed with 0.9 percent saline solution (SS) (n = 5), and washed with a buffered 12.6 percent solution of ACD-A in 0.9 percent saline solution (n = 5). After transfusion, we measured TBT at 1, 4, and 24 hours; platelet survival at 10 minutes and 1, 4, and 24 hours and daily for 6 days; and the percentage of uptake in liver and spleen by quantitative whole-body radionuclide scintigraphy at 24 and 190 hours. We found that saline washing affected platelet recovery, 23.47 +/- 12 percent (p less than 0.001) as compared to 52.43 +/- 17 percent (p less than 0.002) for ACD-saline and 73.17 +/- 8 percent for control; that saline washing resulted in a greater liver uptake than control and ACD-saline-washed platelets (31.9 +/- 8% [p less than 0.001] vs 17.7 +/- 4.1 and 19.3 +/- 2.1% [p greater than 0.1], respectively); that, unlike control and ACD-saline-washed platelets, saline-washed platelets did not shorten bleeding time; and that neither type of washing affected survival. Although ACD-saline washing affects recovery, it also results in intact function, normal survival, higher recovery than SS platelets, and no significant liver uptake.     

Rate-Responsive Pacing: Clinical Experience

Single chamber, rate-responsive pacing is emerging as a new modality in cardiac pacing and in ihe near future, dual chamber rule-responsive pacing may be the optimal solution for most pacemaker patients. In this report we describe our short- and long-term clinical experience with two different rate-responsive pacemakers: the RS4, an asynchronous atrial sensing ventricular pacemaker, and the TX-pacemaker, which senses the evoked QT after a ventricular paced beat, as an indicator of metoholic demand. Both systems use a single ventricular lead. Nine palients received RS4 and 10 palients received TX units. All of these patients had AV block and good ventricular function except for three patients with sinas node disease in the TX group. Between 1 and 3 months after implantation, a 24-hour Holter monitoring was performed, durifig which two maximal symptom-limited treadmill exercise tests (Bruce protocol) were conducted in VVI (70 bpm) and rate-responsive modes, in a random fashion. The mean follow-up was 25 months in RS4 group and 10 months in TX group. Significant improvements in patient exercise tolerance were found in the rate-responsive mode (9.0 vs. 6.6 METs in VVI) with similar results in both groups (RS4 and TX) despite higher ventricular pacing rates in the TX group (721 bpm vs. 102 bpm in RS4). An autolimited rate-responsive pacemaker-mediated tachycardia, induced by retrograde ventriculoatrial conduction, was observed in a patient with an RS4. There are still many problems with these units; at the end of follow-up, only 4 out of 9 with the RS4 unit and 9 out of 10 with the TX unit have pacers that are functioning properly. Single chamber rate-responsive pacing should be considered as a step forward in cardiac pacing.     

Composition of peripheral blood progenitor cell components collected from healthy donors

BACKGROUND: Peripheral blood progenitor cell (PBPC) components are being collected from healthy donors for allogeneic transplantation, but the quantity, quality, composition, and variability of PBPCs collected from healthy people given granulocyte-colony-stimulating factor (G-CSF) have not been evaluated. STUDY DESIGN AND METHODS: PBPC components were collected from 150 healthy people who were given G-CSF (5, 7.5, or 10 microg/kg/day) for 5 days. The components were evaluated for white cell (WBC), mononuclear cell, CD34+ cell, neutrophil, platelet, and red cell (RBC) composition. RESULTS: The quantities collected were: WBCs, 35.0 +/? 16.4 × 10(9) (range, 11.9–163.3 × 10(9)); mononuclear cells, 33.3 +/? 14.4 × 10(9) (range, 11.9–139.6 × 10(9)); CD34+ cells, 412 +/? 287 × 10(6) (range, 70–1658 × 10(6)); neutrophils, 1.71 +/? 3.59 × 10(9) (range, 0–27.6 × 10(9)); RBCs, 7.2 +/? 4.0 mL (range, 0–22.1 mL); and platelets, 480 +/? 110 × 10(9) (range, 250–920 × 10(9)). PBPC components collected from people given G-CSF at 7.5 or 10 microg per kg per day contained significantly more CD34+ cells (respectively, 428 +/? 300 × 10(6); range, 70–1658 × 10(6) and 452 +/? 294 × 10(6); range, 78- 1380 × 10(6)) than those from people given G-CSF at 5 microg per kg per day (276 +/? 186 × 10(6); range, 91–767 × 10(6)) (p = 0.007 and p = 0.002). When 10 microg per kg per day of G-CSF was given, 50 percent of the components contained enough CD34+ cells for transplantation to a 75- kg recipient (375 × 10(6) CD34+ cells), but 10.6 percent of the components contained less than 150 × 10(6) CD34+ cells and thus would provide a transplantable dose only for a 30-kg patient. CONCLUSION: One PBPC component collected from a healthy donor given 7.5 or 10 microg per kg per day of G-CSF should contain 70 to 1660 × 10(6) CD34+ cells, with 0 to 22 mL of RBCs. Because of the great variability in the number of CD34+ cells collected, the quantity of CD34+ cells in each component should be measured after each procedure to ensure that sufficient quantities of cells are present for a successful transplant.     

In vivo viability and functional integrity of filtered platelets

The in vivo viability and functional integrity of filtered platelets were compared with those of nonfiltered platelets in a controlled study. On two occasions, after template bleeding time, 14 healthy volunteers underwent plateletpheresis and received 600 mg of aspirin. Autologous 111In-labeled platelets were transfused without further manipulation (control) on one occasion and after filtration on a second occasion. The filter was primed and flushed with a buffered 12.6-percent solution of ACD-A in 0.9-percent normal saline (pH 6.5). After transfusion, the bleeding time was measured at 1, 4, and 24 hours and platelet survival at 10 minutes; 1, 4, and 24 hours; and daily for 6 days. The decrease in the bleeding time was not significantly different from that after transfusion of nonfiltered platelets (p greater than 0.2). Filtering of platelets did not affect 1-hour in vivo recovery (filtered, 69.5%; nonfiltered, 66%: p = 0.56) or the platelet survival (filtered platelet t1/2 = 83.0 hours, nonfiltered platelet t1/2 = 82.9 hours: p = 0.96). It can be concluded that filtration does not adversely affect in vivo recovery, survival, or functional integrity of platelets.     

Role of arginase in killing of schistosomula of schistosoma mansoni

Nonspecific resistance to the multicellular organism Schistosoma mansoni can be induced in mice by several infectious agents. We utilized the observed genetic restriction of such acquired resistance to study the mediators of killing of the larval stage of S. mansoni in vitro. Adherent peritoneal cell monolayers from Corynebacterium parvum-treated C57BL/6J but not from C. parvum-treated BALB/cJ mice killed an increased proportion of schistosomula in 24 h. Activated macrophages (M) from both strains exhibited enhanced H(2)0(2) production after incubation with the parasites or phorbol myristate acetate. Thus H(2)0(2) production was not associated with schistosomula killing. Moreover, schistosomula killing was unaffected by catalase or superoxide dismutase. In contrast, activated C57BL/6J (but not BALB/cJ) M released fourfold more arginase into supernates than control M. Schistosomula killing by these M correlated with arginase content of the supernates, was exaggerated in arginine-poor medium, and could be blocked by the addition of arginine. Exogenous bovine arginase added to Fischer's medium without macrophages produced comparable parasite mortality. Our data suggest that arginase is a critical mediator of in vitro killing of this multicellular organism by activated macrophages.     

九寨沟景区急诊病例疾病谱调查

目的探讨九寨沟景区急诊患者疾病谱流行病学特点,提高九寨沟景区急诊患者的诊治水平。方法对2013年1~12月四川省九寨沟县人民医院14 196例急诊病例资料进行回顾性分析。结果院前急诊病种排序在前4位的是呼吸系统疾病、高原反应、损伤、心脑血管疾病,呼吸系统疾病患病比例最高,达60.44%;呼吸系统疾病、高原反应、损伤发生率女性高于男性,心脑血管疾病发生率男性明显高于女性;高原反应、损伤、心脑血管疾病以60岁以上人群为主。结论在类似九寨沟这种高寒景区,老年旅游者需要特别重视对呼吸系统疾病、高原反应、损伤、心脑血管疾病的预防。     

T lymphocytes in skin lesions of psoriasis and mycosis fungoides express B7-1: a ligand for CD28

The activation of T cells requires two distinct signals. One signal involves interaction of the antigen-specific T-cell receptor with major histocompatibility complex molecules plus antigenic peptide; a second signal, which is antigen nonspecific, is the interaction of CD28 with its natural ligands B7-1 and B7-2/B70. CD28 is expressed on 80% of T cells, is upregulated after activation, and binds to B7 gene-family members, found on antigen-presenting cells. Because of our interest in the immunologic basis of benign and malignant T-cell-mediated disorders of the skin, we investigated the cellular distribution of CD28 and B7 family members in lesions of psoriasis and mycosis fungoides. By immunostaining cryostat sections of skin, CD28 was found to be expressed on virtually all lymphocytes in the epidermis and dermis of both skin diseases. Surprisingly, B7-1 was also found to be expressed on virtually all lymphocytes in the epidermis and dermis of both skin diseases. B7-1 expression was confirmed on CD3+ T lymphocytes using flow cytometry of single cell suspensions of fresh, unfixed psoriatic lesional tissue. To exclude the possibility that this result was caused by a second reagent contaminating the monoclonal antibody (MoAb) preparation, two different lots were used, and the MoAb was absorbed onto Chinese hamster ovary (CHO) transfectants expressing B7-1, or vector-only transfected CHO cells. These procedures confirmed that a B7- 1-like epitope was being recognized on psoriatic lesional T cells. In contrast to B7-1 expression on lymphocytes, B7-3, as defined by anti-BB- 1 MoAb reactivity, was found primarily on epidermal keratinocytes in both skin diseases and was not found on T cells. These results indicate that within two common skin disorders, lesional T cells accumulate in the dermis and epidermis, which express B7-1. Such expression may permit self-costimulation involving the CD28-mediated activation pathway, and thereby contribute to the ongoing T-cell proliferation present in these chronic, benign, and malignant skin diseases.