Leukocyte apoptosis and its significance in sepsis and shock

Sepsis and multiple organ failure continue to be significant problems among trauma, burn, and the critically ill patient population. Thus, a number of laboratories have focused on understanding the role of altered apoptotic cell death in contributing to immune and organ dysfunction seen in sepsis and shock. Immune cells that undergo altered apoptotic changes include neutrophils, macrophages, dendritic cells, as well as various lymphocyte populations. Evidence of epithelial as well as endothelial cell apoptotic changes has also been reported. Although mediators such as steroids, tumor necrosis factor, nitric oxide, C5a, and Fas ligand (FasL) appear to contribute to the apoptotic changes, their effects are tissue- and cell population-selective. As inhibiting Fas-FasL signaling (e.g., gene deficiency, Fas fusion protein, or Fas short interfering RNA administration), caspase inhibition (caspase mimetic peptides), and/or the overexpression of downstream antiapoptotic molecules (e.g., Bcl-2, Akt) improve survival of septic mice, it not only demonstrates the pathological significance of this process but points to novel targets for the treatment of sepsis.     

Stimulation of β-adrenoceptors inhibits store-operated channel currents via a cAMP-dependent protein kinase mechanism in rabbit portal vein myocytes

Previously we have described the properties of store-operated channel currents (SOCs) in freshly dispersed rabbit portal vein smooth muscle cells. In addition to Ca²⁺ store depletion these SOCs could also be activated by α-adrenoceptor stimulation and diacylglycerol (DAG) via a protein kinase C (PKC)-dependent mechanism. In the present study we have investigated the effect of β-adrenoceptor stimulation on SOCs in rabbit portal vein myocytes. With whole-cell recording the selective β-adrenoceptor agonist isoprenaline reduced the current evoked by cyclopiazonic acid (CPA, sarcoplasmic/endoplasmic reticulum ATPase inhibitor) by over 85%. With cell-attached patch recording, bath application of isoprenaline produced a pronounced inhibition of SOC activity evoked by either CPA or the acetoxymethyl ester form of BAPTA (BAPTA-AM). SOC activity evoked by CPA, the DAG analogue, 1-oleoyl-acetyl- sn -glycerol (OAG) or the phorbol ester, phorbol-12,13-dibutyrate (PDBu) was also markedly inhibited by the adenylate cyclase activator, forskolin, and the cell-permeable non-hydrolysable analogue of cyclic adenosine monophosphate (cAMP), 8-Br-cAMP. With inside-out patches, bath application of PDBu evoked channel currents with similar properties to SOCs which were inhibited by over 90% by a catalytic subunit of protein kinase A (PKA) and by 8-Br-cAMP. Moreover bath application of PKA inhibitors, H-89, KT5720 and an inhibitory peptide to quiescent cell-attached or inside-out patches, activated channel currents with similar properties to SOCs. These data suggest that in rabbit portal vein myocytes, stimulation of β-adrenoceptors inhibits SOC activity via a cAMP-dependent protein kinase signal transduction cascade. In addition it is concluded that constitutive PKA activity has a profound inhibitory effect on SOC activity in this vascular preparation.     

RENAL MEDULLARY CARCINOMA: A Potential Sickle Cell Nephropathy of Children and Adolescents

An extremely aggressive malignant epithelial neoplasm of the kidney has recently been described and named renal medullary carcinoma. The finding of this tumor is highly predictive of drepanocytes (sickle cells) in tissue sections and thus the presence of sickle hemoglobin, specifically sickle cell trait, in the patient. We present a case report of this rare tumor in a 10-year-old male. The tumor displayed a variable histologic architecture including gland-like areas with intra- and extracytoplasmic material resembling mucin with hematoxylin and eosin stain. This material was negative with periodic acid-Schiff and mucicarmine stains, stained only weakly with Alcian Blue, and was positive using antibodies against peanut agglutinin. Tumor cells stained positively with antibodies to epithelial membrane antigen, cytokeratin, vimentin, and Ulex europaeus lectin. The luminal face of tumor cells stained with peanut agglutinin. Stains using antibodies against carcinoembryonic antigen and alpha-fetoprotein were negative. Ultrastructurally, the tumor cells were characterized by short microvilli lining the luminal surface and lateral complex infoldings of adjacent plasma membranes. We discuss the relationship of this neoplasm to another renal pelvic neoplasm, collecting duct carcinoma, which may rarely occur in children. Renal medullary carcinoma should be included in the differential diagnosis of gross hematuria, which is most commonly benign self-limited hematuria, in young patients with sickle cell trait.     

凌晨3:00皮下注射短效胰岛素治疗2型糖尿病黎明现象

目的:观察应用凌晨3:00皮下注射短效胰岛素治疗2型糖尿病黎明现象的疗效。方法:对40例有黎明现象的2型糖尿病患者,使用短效胰岛素凌晨3:00注射4~6U。抽取肘静脉血测定空腹血糖(FPG)及早餐后2h血糖(2hPG),免疫比浊法测定糖化血红蛋白(HbA1c),比较治疗前后上述指标变化。结果:本组患者FPG从治疗前(9.5±1.6)mmol/L下降至(6.0±0.4)mmol/L,治疗2个月后仍保持为(5.6±0.4)mmol/L;2hPG从治疗前(13.8±0.8)mmol/L下降至(7.4±0.4)mmol/L,在治疗2个月后保持为(7.9±0.3)mmol/L;FPG和2hPG与治疗前比较,均具有显著性差异(P<0.01)。治疗2个月后,HbA1c从治疗前(8.3±0.6)%下降至(6.5±0.3)%,与治疗前比较,有显著性差异(P<0.01)。结论:短效胰岛素强化治疗黎明现象具有快速稳定的降血糖和降糖化血红蛋白作用。