Early immunomodulatory effects of linezolid in a human whole blood endotoxin model.

Gram-negative sepsis resulting in endotoxin triggered septic shock is one of the leading causes of death in critically ill patients. Because treatment options are limited, recent approaches focus on immunomodulatory effects of antimicrobials. Thus, we characterized the immunomodulatory effects of linezolid at mRNA and on cytokine levels in supernatants of an ex vivo model of endotoxemia. Whole blood from 10 healthy volunteers was incubated with 50 pg/ml LPS with or without 13 microg/ml linezolid (concentrations were chosen to reflect in vivo conditions) for 2 and 4 hours (h). Quantitative real-time PCR was performed from messenger RNA (mRNA) of IL-1beta;, IL-6, IL-8 or TNF-alpha;. Cytokine levels in the supernatant were measured by ELISA for IL-6, IL-8 and TNF-alpha;. Incubation of human whole blood with LPS increased mRNA levels of cytokines several thousand fold compared with baseline. The addition of linezolid significantly reduced mRNA levels of IL-1beta, IL-6, IL-8 and TNF-alpha; (p < 0.05) after 2 and 4 h. LPS stimulation also increased levels of IL-6, IL-8 and TNF-alpha between 100 and 1000-fold. However, in contrast to mRNA - except for IL-6 - no significant reduction at protein level was observed. These results indicate that immunosuppressive effects of linezolid on mRNA transcription are only partially reflected by cytokine release.

HERG1 gene expression as a specific tumor marker in colorectal tissues.

INTRODUCTION: Colorectal carcinomas exhibit a frequent recurrence after curative surgery, which may partially be due to histopathologically inconspicuous minimal residual disease. Reliable markers for tumor cells in colorectal tissue are still missing. Therefore, in this study we compared the predictive value of the putative tumor markers carcinoembryonic antigen (CEA), cytokeratin-19 (CK19) and cytokeratin-20 (CK20) to that of a novel marker, the human ether-a-go-go-related gene (HERG1) K(+) channel, a suggested regulator of tumor cell proliferation. MATERIALS AND METHODS: Using RT-PCR we studied HERG, CEA, CK19 and CK20 expression in colorectal carcinomas and non-carcinoma controls. HERG1 immunhistochemistry was performed in a total of 66 specimens, in colorectal carcinoma (n = 23), in matched histopathologically negative samples (n = 23) taken near the excision site from the same tumor patients and in healthy control biopsies (n = 20). In order to verify the relevance of HERG1 for tumor proliferation we studied the effect of HERG1 inhibition in the Colo-205 colon cancer carcinoma cell line using the MTT-assay. RESULTS: HERG1 was expressed in all tumor samples regardless of their stage and in adenomas larger than 0.4 cm, but absent in small adenomas, sigmadiverticulitis specimen and healthy histopathologically negative samples, except for one which developed a tumor recurrence. In contrast, CEA, CK19 and CK20 were absent in some tumors. The selective HERG1 inhibitor E-4031 dose-dependently impaired tumor growth in the proliferation assays. DISCUSSION: Our data indicate that HERG1, but not CEA, CK19 or CK20, is a highly sensitive and reliable tumor biomarker that may constitute a novel molecular target for tumor treatment.

T cell senescence and contraction of T cell repertoire diversity in patients with chronic obstructive pulmonary disease.

Pathogenetic mechanisms leading to chronic obstructive pulmonary disease (COPD) remain poorly understood. Because clonogenic T cells (CD4(+)CD28(null)) were shown to be increased in autoimmune diseases we hypothesized that CD4(+)CD28(null) T cells play a role in COPD. Here we describe that enhanced presence of CD4(+)CD28(null) cells is associated with impaired lung function. Sixty-four patients and controls were included. T cell phenotype was analysed using flow cytometry. Enzyme-linked immunosorbent assays were utilized to determine cytokines. Statistical evaluations were performed using non-parametric group comparisons and correlations. A logistic regression model was used to determine predictive values of CD4(+)CD28(null) in the diagnosis of COPD. Populations of CD4(+) T cells lacking surface co-stimulatory CD28 were enlarged significantly in evaluated patients when compared with controls. Natural killer (NK)-like T cell receptors (CD94, 158) and intracellular perforin, granzyme B were increased in CD4(+)CD28(null) cells. Cytokine production after triggering of peripheral blood mononuclear cells (PBMCs) was elevated in patients at early disease stages. Receiver operating characteristic curve plotting revealed that presence of CD4(+)CD28(null) T cells has a diagnostic value. These CD4(+)CD28(null) T cells show increased expression of NK-like T cell receptors (CD94, 158) and intracellular perforin and granzyme B. Furthermore, triggering of PBMCs obtained from patients with mild COPD led to increased interferon-gamma and tumour necrosis factor-alpha production in vitro compared with controls. Our finding of increased CD4(+)CD28(null) T cells in COPD indicates that chronic antigen exposure, e.g. through contents of smoke, leads to loss of CD28 and up-regulation of NK cell receptors expression on T cells in susceptible patients.

Omeprazole in Zollinger-Ellison syndrome. Effects of a single dose and of long-term treatment in patients resistant to histamine H2-receptor antagonists.

We studied the effect of omeprazole, a benzimidazole inhibitor of gastric acid secretion, in patients with Zollinger-Ellison syndrome. In five patients ingestion of 80 mg of omeprazole inhibited gastric acid secretion by 26 to 100 per cent after 6 hours and by 76 to 100 per cent after 24 hours. Seven patients were continuously treated with omeprazole once or twice daily for 8 to 19 months (average, 14). Six of these seven had symptoms that were resistant to high doses of histamine H2-receptor antagonists, and the seventh could not take high doses of cimetidine because of a possible drug-related increase in the serum creatinine concentration. Symptoms resolved in all patients within two weeks, and peptic lesions were healed at endoscopy after four weeks. All patients remained free of symptoms, and gastric acid secretion continued to be markedly inhibited by omeprazole therapy. We conclude that omeprazole is a potent and long-acting antisecretory drug in patients with Zollinger-Ellison syndrome and that it is effective in patients whose peptic-ulcer disease is relatively resistant to treatment with histamine H2-receptor antagonists. Its safety and effectiveness in long-term therapy remain to be assessed.