Human toll-like receptor 4 (hTLR4) and CD14 are known to be components of the lipopolysaccharide receptor complex. Our study investigated the association between TLR4 mutations (Asp299Gly and Thr399Ile) and CD14 polymorphism(s) with outcome in an intensive care unit (ICU) population at risk for sepsis. By use of a polymerase chain reaction-based restriction fragment-length polymorphism analysis technique, the hTLR4 gene was altered in 14 (18%) of 77 ICU patients (all positive for systemic inflammatory response syndrome) and in 5 (13%) of 39 volunteers. There was a significantly higher incidence of gram-negative infection among patients with the mutations (11 [79%] of 14), compared with that in the wild-type population (11 [17%] of 63; P=.004). No association between CD14 polymorphism(s) and the incidence of infection or outcome was observed. These findings indicate that hTLR4 mutations are associated with an increased incidence of gram-negative infections in critically ill patients in a surgical setting.

SummaryThe alpha 7 nicotinic receptor is reportedly a key element in the cholinergic anti-inflammatory pathway. Because a prototypical ligand for this receptor is nicotine, we studied the in vivo human response to bacterial endotoxin or lipopolysaccharide (LPS) in the context of nicotine or placebo pretreatment. Twelve adult male normal subjects were studied prospectively. Six received overnight transcutaneous nicotine administration by application of a standard patch (7 mg). Six hours later, all subjects were given an intravenous dose of endotoxin (2 ng/kg) and were evaluated for an additional 24 h for circulating levels of inflammatory biomarkers, vital signs and symptoms. The nicotine subjects had elevated blood levels of the nicotine metabolite, continine, prior to and throughout the 24-h post-endotoxin exposure phase. Subjects receiving nicotine exhibited a significantly lower temperature response as well as attenuated cardiovascular responses for 2·5-6 h after LPS exposure. In addition, increased circulating interkeukin (IL)-10 and cortisol levels were also noted in nicotine subjects. These data indicate an alteration in LPSinduced systemic inflammatory responses in normal subjects exposed to transcutaneous nicotine. In this model of abbreviated inflammation, nicotine exposure attenuates the febrile response to LPS and promotes a more prominent anti-inflammatory phenotype.

The presence of the A allele at these polymorphic sites did not predispose critically ill surgical patients to either infection or septic shock.

Gliotoxin is produced by the fungus Aspergillus fumigatus. Aspergillus is widespread in the environment and this ubiquitous nature results in disease and co-carcinogenesis to be distributed world-wide. Gliotoxin contains an epipolythiodioxopiperazine (ETP) ring that is believed to be involved in redox reactions. The reactive oxygen species produced interact with DNA to form hydroxylated and other altered DNA products. To measure DNA adduct formation, we used 32P radiolabelling and, after enzymatic DNA digestion, separated adducts in two dimensions using thin-layer chromatography (2D-TLC), with ultimate autoradiography and densitometry. HeLa DNA was incubated with 0.1 mmol l-1 and 0.3 mmol l-1 of gliotoxin (and necessary redox agents) for 1 and 20 h. We found an increase in 6-hydro-5,6-dihydroxythymidine (thymine glycol) monophosphate [d(TG)MP] from 0.0% to 30.4%, an increase in 8-hydroxy-2'-deoxyguanidine monophosphate [8(OH)dGMP] from 0.0% to 4.2%, an increase in deoxynucleotide diphosphate (dNDP) from zero adducts to six DNA adducts, as well as an increase of other as yet unidentified adducts. Also, time exposure may have a greater effect than concentration based on a 20-h incubation with 0.3 mmol l-1 gliotoxin that completely obliterates the pyrimidines deoxythymidine 3'-monophosphate (dTMP) and deoxycytidine 3'-monophosphate (dCMP).

Platinum-based chemotherapies cause the formation of DNA adducts and have profound effects on DNA. This study measured cis-diamminedichloroplatinum II (cisplatin) DNA adducts by 32P-radiolabeling DNA, enzymatically digesting radiolabeled DNA, separating the formed adducts on two-dimensional thin-layer chromatography, and quantitating the adducts with autoradiography and densitometry. HeLa DNA was incubated with cisplatin at varying concentrations (6.25-325 nM) and times (0 min to 72 hr). Cisplatin rapidly depurinated dGMP and dAMP (90%, 15-min incubation with 325 nM cisplatin). Partial depurination of dGMP (15%) and dAMP (25%) occurred with lower cisplatin concentrations at equal incubation times. A minimum of four new adducts, with relatively rapid migratory patterns, were detected at high cisplatin concentrations with short incubation times. These results indicate that the depurination of DNA correlates with DNA adduct formation and that the quantification of these adducts may be applicable to monitoring tumor and host cell response to cisplatin chemotherapy.

Adriamycin (ADM, or doxorubicin hydrochloride) is an effective antineoplastic agent whose use is restricted by its well-described, dose-dependent cardiotoxicity. This study measures ADM DNA adduct formation by 32P-radiolabeling DNA, enzymatically digesting radiolabeled DNA, separating the formed adducts on two-dimensional thinlayer chromatography (2D-TLC), and quantitating the adducts with autoradiography and densitometry. Thirty-six male Sprague-Dawley rats are randomized to receive ADM at varying intraperitoneal (i.p.) injection concentrations: 0.9% saline i.p. controls, 4 mg/kg ADM i.p., and 6 mg/kg ADM i.p. Myocardial and pulmonary tissues are harvested 48 hours after i.p. injection for autoradiographic and histopathologic analyses. The results indicate differences in the amount and type of adduct formation as a function of ADM concentration. Increased partial depurination of dGMP and dAMP occurs with increasing ADM concentration at equal incubation times. This depurination correlates with the emergence of new adducts HM-dUMP, 8-OH-dGMP, HM-dCMP, and Me-dCMP. The quantification of these adducts can potentially represent an early marker of ADM cardiotoxicity and thereby optimize the efficacy of individual chemotherapy regimens while minimizing adverse effects.

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THP-1 cell apoptosis is increased in response to LPS stimulation and is associated with a significant induction of IGFBP-3 mRNA and protein. IGFBP-3, which reportedly promotes apoptosis and modulates the bioavailability of the pro-survival insulin-like growth factor 1, may serve to regulate apoptosis in monocytic cells in an IGF-independent manner. These data further support the investigation of the role of the IGF axis in programmed cell death of immune cells.