Characterization of normal peripheral blood lymphocyte colony-forming cells: cell cycle status, surface markers, and cellular growth requirements

We performed a series of studies to further clarify the nature of lymphocyte colony-forming cells (CFC) from normal peripheral blood. Mononuclear cells were separated into E-rosette-enriched (E+) and E- rosette-depleted (E-) populations and cultured in methylcellulose with conditioned media and irradiated mononuclear cells. Linear plating relationships were obtained with plating efficiencies of 0.26% +/- .02% (mean +/- SE) for E+ CFC and 0.18% +/- .02% for E- CFC. Cells in E+ colonies were T lymphocytes and in E- colonies were B lymphocytes as determined by cell surface marker analysis. Using the thymidine suicide technique, approximately one-half of CFC were found to be in cycle at any moment, and plating efficiencies and cell cycle status of E+ CFC were not changed by preincubation with PHA in liquid culture for 48 hr. Using antibody complement-mediated cytotoxicity, E+ CFC were found to be T101+, OKT3+, and Ia-, while E- CFC were OKT3- and Ia+. Using monocyte-depleted populations obtained by sedimentation at unit gravity, lymphocyte colony growth was absent in monocyte-depleted fractions, and optimal growth occurred with 40% monocytes in culture. In contrast to some previous studies, we find that lymphocyte CFC originate from a small, cycling population of cells bearing mature T or B lymphocyte markers. Entry into cell division, however, does not confer colony-forming capacity on lymphocytes. Monocytes are critical to growth of E+ CFC, and cultures severely depleted of monocytes would not be expected to form colonies.     

Multilineage hematopoietic growth factor interleukin 3 and direct activators of protein kinase C stimulate phosphorylation of common substrates

In order to investigate early signal transduction events in myeloid cells, the phosphosubstrates of an interleukin 3 (IL 3)-dependent cell line, FDC-P1, have been analyzed. Using synthetic diacylglycerol as a direct activator of the unique calcium-phospholipid-dependent phosphotransferase protein kinase C (PK-C) and genetically engineered homogeneous IL 3, we have demonstrated a common element to signal transduction events associated with these stimulants. One novel substrate, p68 (68,000 kd), was rapidly phosphorylated in either IL 3- or diacylglycerol-stimulated cells. The phosphorylation of p68 was dose- dependent, with both the physiological ligand and diacylglycerol inducing the same maximal level of phosphorylation. Phosphorylation of p68 occurred in a time-dependent manner analogous to previously described kinetics of PK-C subcellular redistribution in the FDC-P1 cell line. The p68 substrate was also phosphorylated in a cell-free system under conditions designed to activate PK-C. Phosphoamino acid analysis demonstrated that the p68 molecule phosphorylated in intact cells as well as in a calcium-phospho-lipid-dependent cell-free system was phosphorylated on threonine residues, not tyrosine. These data support the hypothesis that the activation of PK-C that occurs after IL 3-receptor interaction which leads to the rapid phosphorylation of cellular proteins is an important element of the signal transduction mechanism in FDC-P1 cells. We propose that phosphorylation of the p68 molecule is a physiochemical marker for the activation of PK-C in myeloid cells, in response to the growth-promoting physiological ligand.     

High frequency of N-ras activation in acute myelogenous leukemia

Using the NIH/3T3 cell transfection assay, activated cellular oncogenes have been detected in around 10% to 20% of human tumors. From a series of DNA preparations from tissues infiltrated with acute myelogenous leukemia (AML), 50% (3/6) caused transformation of NIH/3T3 cells. Thus AML appears to be the human tumor with the highest frequency of oncogenes detected by DNA transfection. In each case the oncogene involved was N-ras, a member of the ras gene family. Biologic and clinical parameters of AML patients with and without N-ras oncogenes in their tumors are discussed.     

Expression of cell surface receptors and oxidative metabolism modulation in the clinical continuum of sepsis

Background  

Infection control depends on adequate microbe recognition and cell activation, yet inflammatory response may lead to organ dysfunction in sepsis. The aims of this study were to evaluate cell activation in the context of sepsis and its correlation with organ dysfunction.     

Dopamine increases renal oxygenation: a clinical study in post‐cardiac surgery patients

Background: Imbalance of the renal medullary oxygen supply/demand relationship can cause ischaemic acute renal failure (ARF). The use of dopamine for prevention/treatment of ischaemic ARF has been questioned. It has been suggested that dopamine may increase renal oxygen consumption (RVO₂) due to increased solute delivery to tubular cells, which may jeopardise renal oxygenation. Information on the effects of dopamine on renal perfusion, filtration and oxygenation in man is, however, lacking. We evaluated the effects of dopamine on renal blood flow (RBF), glomerular filtration rate (GFR), RVO₂ and renal O₂ demand/supply relationship, i.e. renal oxygen extraction (RO₂Ex). Methods: Twelve uncomplicated, mechanically ventilated and sedated post‐cardiac surgery patients with pre‐operatively normal renal function were studied. Dopamine was sequentially infused at 2 and 4 ug/kg/min. Systemic haemodynamics were evaluated by a pulmonary artery catheter. Absolute RBF was measured using two independent techniques: by the renal vein thermodilution technique and by infusion clearance of paraaminohippuric acid (PAH), with a correction for renal extraction of PAH. The filtration fraction (FF) was measured by the renal extraction of ⁵¹Cr‐EDTA. Results: Neither GFR, tubular sodium reabsorption nor RVO₂ was affected by dopamine, which increased RBF (45–55%) with both methods, decreased renal vascular resistance (30–35%), FF (21–26%) and RO₂Ex (28–34%). The RBF/CI ratio increased with dopamine. Dopamine decreased renal PAH extraction, suggestive of a flow distribution to the medulla. Conclusions: In post‐cardiac surgery patients, dopamine increases the renal oxygenation by a pronounced renal pre‐and post‐glomerular vasodilation with no increases in GFR, tubular sodium reabsorption or renal oxygen consumption.     

持续腰池脑脊液引流治疗隐球菌性脑膜炎的临床探讨

0引言 隐球菌性脑膜炎(隐脑)是由隐球菌属中某些种或变种侵犯中枢神经系统引起的一种深部真菌病. 隐脑在我国仍以散发为主,近年来发病呈明显上升的趋势;而在一些发展中国家,AIDS患者隐脑的发病率更高[1]. 隐脑的误诊率较高,其治疗中存在较多问题,因为在现有的抗真菌治疗条件下,国内外文献报道其病死率仍高达25%～60%[1]. 现将我科1997-01/2005-01收治的19例中,进行了持续腰池脑脊液(CSF)引流的9例隐球菌脑膜炎患者与对照组10例观察报告如下,探讨有效的治疗手段.