DNA polymerase lambda (pol ) is a novel family X DNA polymerase that has been suggested to play a role in meiotic recombination and DNA repair. The recent demonstration of an intrinsic 5-deoxyribose-5-phosphate lyase activity in pol supports a function of this enzyme in base excision repair. However, the biochemical properties of the polymerization activity of this enzyme are still largely unknown. We have cloned and purified human pol to homogeneity in a soluble and active form, and we present here a biochemical description of its polymerization features. In support of a role in DNA repair, pol inserts nucleotides in a DNA template-dependent manner and is processive in small gaps containing a 5-phosphate group. These properties, together with its nucleotide insertion fidelity parameters and lack of proofreading activity, indicate that pol is a novel ␤-like DNA polymerase. However, the high affinity of pol for dNTPs (37-fold over pol ␤) is consistent with its possible involvement in DNA transactions occurring under low cellular levels of dNTPs. This suggests that, despite their similarities, pol ␤ and pol have nonredundant in vivo functions.

The relationship between fluctuating cytokine concentrations in plasma and the outcome of sepsis is complex. We postulated that early measurement of the activation of nuclear factor B (NF-B), a transcriptional regulatory protein involved in proinflammatory cytokine expression, may help to predict the outcome of sepsis. We determined NF-B activation in peripheral blood mononuclear cells of 34 patients with severe sepsis (23 survivors and 11 nonsurvivors) and serial concentrations of inflammatory cytokines (interleukin-6, interleukin-1, and tumor necrosis factor) and various endogenous antagonists in plasma. NF-B activity was significantly higher in nonsurvivors and correlated strongly with the severity of illness (APACHE II score), although neither was related to the cytokine levels. Apart from NF-B activity, the interleukin-1 receptor antagonist was the only cytokine tested whose level in plasma was of value in predicting mortality by logistic regression analysis. These results underscore the prognostic value of early measurement of NF-B activity in patients with severe sepsis.Many reports have focused on aspects of the proinflammatory cytokine network, which is believed to be central to the pathophysiology of the sepsis syndrome (5,8). However, the cytokine responses in patients with sepsis appears to vary so much between individuals (10) that the prognostic usefulness of circulating cytokine concentrations is often less than that of clinical variables, such as the acute physiology and chronic health evaluation (APACHE) II or III (9). Other studies indicate that the problem in overwhelming sepsis is not that inflammatory cytokines are expressed but, rather, that their expression is not properly modulated by anti-inflammatory mediators (16,17). Recent investigations by others (3) and ourselves (1) searching for new clinically reliable markers in patients with sepsis have shown that circulating leptin levels, whose secretion is closely linked to the activation of the cytokine cascade (1), may help to predict mortality in sepsis and septic shock.Among several transcriptional regulatory factors involved in immunoregulatory genes expression, nuclear factor kappa B (NF-B) acts at a critical step for directing the transcription of many proinflammatory genes in animal models of inflammatory diseases (6, 7). Investigations regarding the role of NF-B in human inflammatory diseases are scarce (2, 15). So far, no study has aimed to examine in patients with sepsis the relationship between the concentrations of some components of the proinflammatory and anti-inflammatory cytokine response in plasma, NF-B expression in peripheral blood mononuclear cells, and clinical outcome. We hypothesized that severe, fatal sepsis could be distinguished from less severe sepsis by demonstrating greater NF-B activation and decreased anti-inflammatory response. Thus, this study compared the prognostic value of combining measurements of NF-B activity in circulating blood cells and the cytokine profile in plasma in patients with severe sepsis. ...

New dual binding site acetylcholinesterase (AChE) inhibitors have been designed and synthesized as new potent drugs that may simultaneously alleviate cognitive deficits and behave as disease-modifying agents by inhibiting the beta-amyloid (A beta) peptide aggregation through binding to both catalytic and peripheral sites of the enzyme. Particularly, compounds 5 and 6 emerged as the most potent heterodimers reported so far, displaying IC50 values for AChE inhibition of 20 and 60 pM, respectively. More importantly, these dual AChE inhibitors inhibit the AChE-induced A beta peptide aggregation with IC50 values 1 order of magnitude lower than that of propidium, thus being the most potent derivatives with this activity reported up to date. We therefore conclude that these compounds are very promising disease-modifying agents for the treatment of Alzheimer's disease (AD).