These observations indicate that the long-lasting trace of an experience is not completely fixed, consolidated, or coded at the time of the experience. Consolidation requires time, and under at least some circumstances the processes of consolidation appear to be susceptible to a variety of influences- both facilitating and impairing- several hours after the experience. There must be, it seems, more than one kind of memory trace process (31). If permanent memory traces consolidate slowly over time, then other processes must provide a temporary basis for memory while consolidation is occurring. The evidence clearly indicates that trial-to-trial improvement, or learning, in animals cannot be based completely on permanent memory storage. Amnesia can be produced by electroshock and drugs even if the animals are given the treatment long after they have demonstrated "learning" of the task. Of particular interest is the finding that retention of the inhibitory avoidance response increases with time. In a sense this should be expected, for it has long been known (and ignored) that, within limits, learning is facilitated by increasing the interval between repeated trials (7, 30). Our result may be the simplest case of such an effect. Since the improvement in retention with time seemed not to be due solely to consolidation (as indicated by electroshock effects), it would seem that the "distribution of practice" effect, as it is typically designated, may be due in part to a time-dependent temporary memory storage process. In our work with animals we have found no analog of human immediate memory such as that required for repeating digits (or finishing sentences). Animals tested immediately on the task described above after a trial typically showed no evidence of memory. It could be that the poor performance is due to excessive fright, but the "distribution of practice effect" is also typically observed in learning experiments in which food reward is used rather than shock avoidance. Since the retention tasks require the animals to change their behavior in some way, it could well be that the growth of retention over the first few minutes after a trial is due to time dependent processes involved in the organization of processes necessary for changing behavior, in addition to those involved in temporary storage and retrieval. It is worth pointing out that there is evidence of an analogous process in human memory (32). A complex picture of memory storage is emerging. There may be three memory trace systems: one for immediate memory (and not studied in our laboratory); one for short-term memory which develops within a few seconds or minutes and lasts for several hours; and one which consolidates slowly and is relatively permanent. The nature of the durability of the longterm memory trace (that is, the nature and basis of forgetting) is a separate but important issue. There is increasing evidence and speculation (20, 21, 33) that memory storage requires a "tritrace" system, and our findings are at least consistent with such a view. If there are, as seems possible, at least three kinds of traces involved in memory storage, how are they related? Is permanent memory produced by activity of temporary traces (31), or are the trace systems relatively independent? Although available findings do not provide an answer to this question, there does seem to be increasing evidence that the systems are independent. Acquisition can occur, as we have seen, without permanent consolidation, and both short-term and long-term memory increase with time. All this evidence suggests (but obviously does not prove) that each experience triggers activity in each memory system. Each repeated training trial may, according to this view, potentiate short-term processes underlying acquisition while simultaneously enhancing independent underlying long-term consolidation. Obviously, acceptance of these conclusions will require additional research. If this view is substantially correct, it seems clear that any search for the engram or the basis of memory is not going to be successful. Recognition of the possibility that several independent processes may be involved at different stages of memory may help to organize the search. A careful examination of the time course of retention and memory trace consolidation, as well as examination of the bases of the effects of memory-impairing and memory-facilitating treatments, may help to guide the search. It is clear that a complete theory of memory storage must eventually provide an understanding of time-dependent processes in memory. In 1930 Lashley wrote (2), "The facts of both psychology and neurology show a degree of plasticity, of organization, and of adaptation and behavior which is far beyond any present possibility of explanation." Although this conclusion is still valid, the current surge of interest in memory storage offers hope that this conclusion may soon need to be modified.

Cytochrome P450 enzymes are responsible for the phase I metabolism of approximately 75% of known pharmaceuticals. P450s perform this and other important biological functions through the controlled activation of C-H bonds. Here, we report the spectroscopic and kinetic characterization of the long-sought principal intermediate involved in this process, P450 compound I (P450-I), which we prepared in approximately 75% yield by reacting ferric CYP119 with m-chloroperbenzoic acid. The Mössbauer spectrum of CYP119-I is similar to that of chloroperoxidase compound I, although its electron paramagnetic resonance spectrum reflects an increase in |J|/D, the ratio of the exchange coupling to the zero-field splitting. CYP119-I hydroxylates the unactivated C-H bonds of lauric acid [D(C-H) ~ 100 kilocalories per mole], with an apparent second-order rate constant of k(app) = 1.1 × 10(7) per molar per second at 4°C. Direct measurements put a lower limit of k ≥ 210 per second on the rate constant for bound substrate oxidation, whereas analyses involving kinetic isotope effects predict a value in excess of 1400 per second.

Repair of chromosomal breaks is essential for cellular viability, but misrepair generates mutations and gross chromosomal rearrangements. We investigated the interrelationship between two homologous-repair pathways, i.e., mutagenic single-strand annealing (SSA) and precise homology-directed repair (HDR). For this, we analyzed the efficiency of repair in mammalian cells in which double-strand break (DSB) repair components were disrupted. We observed an inverse relationship between HDR and SSA when RAD51 or BRCA2 was impaired, i.e., HDR was reduced but SSA was increased. In particular, expression of an ATP-binding mutant of RAD51 led to a >90-fold shift to mutagenic SSA repair. Additionally, we found that expression of an ATP hydrolysis mutant of RAD51 resulted in more extensive gene conversion, which increases genetic loss during HDR. Disruption of two other DSB repair components affected both SSA and HDR, but in opposite directions: SSA and HDR were reduced by mutation of Brca1, which, like Brca2, predisposes to breast cancer, whereas SSA and HDR were increased by Ku70 mutation, which affects nonhomologous end joining. Disruption of the BRCA1-associated protein BARD1 had effects similar to those of mutation of BRCA1. Thus, BRCA1/BARD1 has a role in homologous repair before the branch point of HDR and SSA. Interestingly, we found that Ku70 mutation partially suppresses the homologous-repair defects of BARD1 disruption. We also examined the role of RAD52 in homologous repair. In contrast to yeast, Rad52(-)(/)(-) mouse cells had no detectable HDR defect, although SSA was decreased. These results imply that the proper genetic interplay of repair factors is essential to limit the mutagenic potential of DSB repair.

The authors review research showing that when recalling autobiographical events, many emotionally disturbed patients summarize categories of events rather than retrieving a single episode. The mechanisms underlying such overgeneral memory are examined, with a focus on M. A. Conway and C. W. Pleydell-Pearce's (2000) hierarchical search model of personal event retrieval. An elaboration of this model is proposed to account for overgeneral memory, focusing on how memory search can be affected by (a) capture and rumination processes, when mnemonic information used in retrieval activates ruminative thinking; (b) functional avoidance, when episodic material threatens to cause affective disturbance; and (c) impairment in executive capacity and control that limits an individual's ability to remain focused on retrieval in the face of distraction.

Drug-induced liver injury (DILI) is a problem of increasing significance, but has been a long-standing concern in the treatment of tuberculosis (TB) infection. The liver has a central role in drug metabolism and detoxification, and is consequently vulnerable to injury. The pathogenesis and types of DILI are presented, ranging from hepatic adaptation to hepatocellular injury. Knowledge of the metabolism of anti-TB medications and of the mechanisms of TB DILI is incomplete. Understanding of TB DILI has been hampered by differences in study populations, definitions of hepatotoxicity, and monitoring and reporting practices. Available data regarding the incidence and severity of TB DILI overall, in selected demographic groups, and in those coinfected with HIV or hepatitis B or C virus are presented. Systematic steps for prevention and management of TB DILI are recommended. These include patient and regimen selection to optimize benefits over risks, effective staff and patient education, ready access to care for patients, good communication among providers, and judicious use of clinical and biochemical monitoring. During treatment of latent TB infection (LTBI) alanine aminotransferase (ALT) monitoring is recommended for those who chronically consume alcohol, take concomitant hepatotoxic drugs, have viral hepatitis or other preexisting liver disease or abnormal baseline ALT, have experienced prior isoniazid hepatitis, are pregnant or are within 3 months postpartum. During treatment of TB disease, in addition to these individuals, patients with HIV infection should have ALT monitoring. Some experts recommend biochemical monitoring for those older than 35 years. Treatment should be interrupted and, generally, a modified or alternative regimen used for those with ALT elevation more than three times the upper limit of normal (ULN) in the presence of hepatitis symptoms and/or jaundice, or five times the ULN in the absence of symptoms. Priorities for future studies to develop safer treatments for LTBI and for TB disease are presented.

Despite recent advances in our understanding of the pathogenesis of attaching and effacing (A/E) Escherichia coli infections, the mechanisms by which the host defends against these microbes are unclear. The goal of this study was to determine the role of goblet cell-derived Muc2, the major intestinal secretory mucin and primary component of the mucus layer, in host protection against A/E pathogens. To assess the role of Muc2 during A/E bacterial infections, we inoculated Muc2 deficient (Muc2(-/-)) mice with Citrobacter rodentium, a murine A/E pathogen related to diarrheagenic A/E E. coli. Unlike wildtype (WT) mice, infected Muc2(-/-) mice exhibited rapid weight loss and suffered up to 90% mortality. Stool plating demonstrated 10-100 fold greater C. rodentium burdens in Muc2(-/-) vs. WT mice, most of which were found to be loosely adherent to the colonic mucosa. Histology of Muc2(-/-) mice revealed ulceration in the colon amid focal bacterial microcolonies. Metabolic labeling of secreted mucins in the large intestine demonstrated that mucin secretion was markedly increased in WT mice during infection compared to uninfected controls, suggesting that the host uses increased mucin release to flush pathogens from the mucosal surface. Muc2 also impacted host-commensal interactions during infection, as FISH analysis revealed C. rodentium microcolonies contained numerous commensal microbes, which was not observed in WT mice. Orally administered FITC-Dextran and FISH staining showed significantly worsened intestinal barrier disruption in Muc2(-/-) vs. WT mice, with overt pathogen and commensal translocation into the Muc2(-/-) colonic mucosa. Interestingly, commensal depletion enhanced C. rodentium colonization of Muc2(-/-) mice, although colonic pathology was not significantly altered. In conclusion, Muc2 production is critical for host protection during A/E bacterial infections, by limiting overall pathogen and commensal numbers associated with the colonic mucosal surface. Such actions limit tissue damage and translocation of pathogenic and commensal bacteria across the epithelium.

The blood-brain barrier (BBB) limits the distribution of systemically administered therapeutics to the central nervous system (CNS), posing a significant challenge to drug development efforts to treat neurological and psychiatric diseases and disorders. Intranasal delivery is a noninvasive and convenient method that rapidly targets therapeutics to the CNS, bypassing the BBB and minimizing systemic exposure. This review focuses on the current understanding of the mechanisms underlying intranasal delivery to the CNS, with a discussion of pathways from the nasal cavity to the CNS involving the olfactory and trigeminal nerves, the vasculature, the cerebrospinal fluid, and the lymphatic system. In addition to the properties of the therapeutic, deposition of the drug formulation within the nasal passages and composition of the formulation can influence the pathway a therapeutic follows into the CNS after intranasal administration. Experimental factors, such as head position, volume, and method of administration, and formulation parameters, such as pH, osmolarity, or inclusion of permeation enhancers or mucoadhesives, can influence formulation deposition within the nasal passages and pathways followed into the CNS. Significant research will be required to develop and improve current intranasal treatments and careful consideration should be given to the factors discussed in this review.

The coxsackievirus and adenovirus receptor (CAR) mediates viral attachment and infection, but its physiologic functions have not been described. In nonpolarized cells, CAR localized to homotypic intercellular contacts, mediated homotypic cell aggregation, and recruited the tight junction protein ZO-1 to sites of cell-cell contact. In polarized epithelial cells, CAR and ZO-1 colocalized to tight junctions and could be coprecipitated from cell lysates. CAR expression led to reduced passage of macromolecules and ions across cell monolayers, and soluble CAR inhibited the formation of functional tight junctions. Virus entry into polarized epithelium required disruption of tight junctions. These results indicate that CAR is a component of the tight junction and of the functional barrier to paracellular solute movement. Sequestration of CAR in tight junctions may limit virus infection across epithelial surfaces.

The rate constant for dissociation of ADP from actomyosin subfragment 1 (S1) has been measured in this laboratory and elsewhere for a variety of vertebrate muscle types. We have made the following observations: (i) In solution, the dissociation of ADP from actomyosin-S1 limits the rate of dissociation of actomyosin-S1-ADP by ATP and, presumably, also limits the rate of crossbridge detachment in contracting muscle. (ii) For muscle types in which the rate of ADP dissociation from actomyosin-S1 is slow enough to measure using stopped-flow methods, the rate constants are nearly the same as the theoretical value for the minimum allowable rate constant for dissociation of an attached crossbridge. Therefore, ADP dissociation is sufficiently slow to be the molecular step that limits the maximum shortening velocity of these muscles. (iii) Variation with muscle type of the rate constant for ADP dissociation may be a general phylogenetic mechanism for regulating shortening velocity.

Inflammation drives the formation, progression, and rupture of atherosclerotic plaques. Experimental studies have demonstrated that an inflammatory subset of monocytes/macrophages preferentially accumulate in atherosclerotic plaque and produce proinflammatory cytokines. T lymphocytes can contribute to inflammatory processes that promote thrombosis by stimulating production of collagen-degrading proteinases and the potent procoagulant tissue factor. Recent data link obesity, inflammation, and modifiers of atherosclerotic events, a nexus of growing clinical concern given the worldwide increase in the prevalence of obesity. Modulators of inflammation derived from visceral adipose tissue evoke production of acute phase reactants in the liver, implicated in thrombogenesis and clot stability. Additionally, C-reactive protein levels rise with increasing levels of visceral adipose tissue. Adipose tissue in obese mice contains increased numbers of macrophages and T lymphocytes, increased T lymphocyte activation, and increased interferon-gamma (IFN-gamma) expression. IFN-gamma deficiency in mice reduces production of inflammatory cytokines and inflammatory cell accumulation in adipose tissue. Another series of in vitro and in vivo mouse experiments affirmed that adiponectin, an adipocytokine, the plasma levels of which drop with obesity, acts as an endogenous antiinflammatory modulator of both innate and adaptive immunity in atherogenesis. Thus, accumulating experimental evidence supports a key role for inflammation as a link between risk factors for atherosclerosis and the biology that underlies the complications of this disease. The recent JUPITER trial supports the clinical utility of an assessment of inflammatory status in guiding intervention to limit cardiovascular events. Inflammation is thus moving from a theoretical concept to a tool that provides practical clinical utility in risk assessment and targeting of therapy.

OBJECTIVE

The purpose of this study is to characterize the clinical profile and identify clinical markers that would enable the detection during life of anomalous coronary artery origin from the wrong aortic sinus (with course between the aorta and pulmonary trunk) in young competitive athletes.

BACKGROUND

Congenital coronary artery anomalies are not uncommonly associated with sudden death in young athletes, the catastrophic event probably provoked by myocardial ischemia. Such coronary anomalies are rarely identified during life, often because of insufficient clinical suspicion. However, since anomalous coronary artery origin is amenable to surgical treatment, timely clinical identification is crucial.

METHODS

Because of the paucity of available data characterizing the clinical profile of wrong sinus coronary artery malformations, we reviewed two large registries comprised of young competitive athletes who died suddenly, assembled consecutively in the U.S. and Italy.

RESULTS

We reported 27 sudden deaths in young athletes, identified solely at autopsy and due to either left main coronary artery from the right aortic sinus (n = 23) or right coronary artery from the left sinus (n = 4). Each athlete died either during (n = 25) or immediately after (n = 2) intense exertion on the athletic field. Fifteen athletes (55%) had no clinical cardiovascular manifestations or testing during life. However, in the remaining 12 athletes (45%) aged 16 +/- 7, certain clinical data were available. Premonitory symptoms had occurred in 10, including syncope in four (exertional in three and recurrent in two, 3 to 24 months before death) and chest pain in five (exertional in three, all single episodes, < or =24 months before death). All cardiovascular tests were within normal limits, including 12-lead electrocardiogram (ECG) pattern (in 9/9), stress ECG with maximal exercise (in 6/6) and left ventricular wall motion and cardiac dimensions by two-dimensional echocardiography (in 2/2).

CONCLUSIONS

With regard to congenital coronary artery anomalies of wrong aortic sinus origin in young competitive athletes, 1) standard testing with ECG under resting or exercise conditions is unlikely to provide clinical evidence of myocardial ischemia and would not be reliable as screening tests in large athletic populations, 2) premonitory cardiac symptoms not uncommonly occurred shortly before sudden death (typically associated with anomalous left main coronary artery), suggesting that a history of exertional syncope or chest pain requires exclusion of this anomaly. These observations have important implications for the preparticipation screening of competitive athletes.

BACKGROUND

Skin-infiltrating lymphocytes expressing type 1 cytokines have been linked to the pathophysiology of psoriasis. We evaluated the safety and efficacy of a human interleukin-12/23 monoclonal antibody in treating psoriasis.

METHODS

In this double-blind, placebo-controlled trial, 320 patients with moderate-to-severe plaque psoriasis underwent randomization to treatment with the interleukin-12/23 monoclonal antibody (one 45-mg dose, one 90-mg dose, four weekly 45-mg doses, or four weekly 90-mg doses) or placebo; 64 patients were randomly assigned to each group. Patients assigned to the interleukin-12/23 monoclonal antibody received one additional dose at week 16 if needed. Patients assigned to placebo crossed over to receive one 90-mg dose of interleukin-12/23 monoclonal antibody at week 20.

RESULTS

There was at least 75% improvement in the psoriasis area-and-severity index at week 12 (the primary end point) in 52% of patients who received 45 mg of the interleukin-12/23 monoclonal antibody, in 59% of those who received 90 mg, in 67% of those who received four weekly 45-mg doses, and in 81% of those who received four weekly 90-mg doses, as compared with 2% of those who received placebo (P<0.001 for each comparison), and there was at least 90% improvement in 23%, 30%, 44%, and 52%, respectively, of patients who received the monoclonal antibody as compared with 2% of patients who received placebo (P<0.001 for each comparison). Adverse events occurred in 79% of patients treated with the interleukin-12/23 monoclonal antibody as compared with 72% of patients in the placebo group (P=0.19). Serious adverse events occurred in 4% of patients who received the monoclonal antibody and in 1% of those who received placebo (P=0.69).

CONCLUSIONS

This study demonstrates the therapeutic efficacy of an interleukin-12/23 monoclonal antibody in psoriasis and provides further evidence of a role of the interleukin-12/23 p40 cytokines in the pathophysiology of psoriasis. Larger studies are needed to determine whether serious adverse events might limit the clinical usefulness of this new therapeutic target. (ClinicalTrials.gov number, NCT00320216 [ClinicalTrials.gov].).

Bacterial populations produce a small number of dormant persister cells that exhibit multidrug tolerance. All resistance mechanisms do essentially the same thing: prevent the antibiotic from hitting a target. By contrast, tolerance apparently works by shutting down the targets. Bactericidal antibiotics kill bacteria by corrupting their targets, rather than merely inhibiting them. Shutting down the targets then protects from killing. The number of persisters in a growing population of bacteria rises at mid-log and reaches a maximum of approximately 1% at stationary state. Similarly, slow-growing biofilms produce substantial numbers of persisters. The ability of a biofilm to limit the access of the immune system components, and the ability of persisters to sustain an antibiotic attack could then account for the recalcitrance of such infections in vivo and for their relapsing nature. Isolation of Escherichia coli persisters by lysing a population or by sorting GFP-expressing cells with diminished translation allowed to obtain a gene expression profile. The profile indicated downregulated biosynthetic pathways, consistent with their dormant nature, and indicated overexpression of toxin/antitoxin (TA) modules. Stochastic overexpression of toxins that inhibit essential functions such as translation may contribute to persister formation. Ectopic expression of RelE, MazF, and HipA toxins produced multidrug tolerant cells. Apart from TA modules, glpD and plsB were identified as potential persister genes by overexpression cloning of a genomic library and selection for antibiotic tolerance. Yeast Candida albicans forms recalcitrant biofilm infections that are tolerant to antibiotics, similarly to bacterial biofilms. C. albicans biofilms produce multidrug tolerant persisters that are not mutants, but rather phenotypic variants of the wild type. Unlike bacterial persisters, however, C. albicans persisters were only observed in a biofilm, but not in a planktonic stationary population. Identification of persister genes opens the way to a rational design of anti-biofilm therapy. Combination of a conventional antibiotic with a compound inhibiting persister formation or maintenance may produce an effective therapeutic. Other approaches to the problem include sterile-surface materials, prodrug antibiotics, and cyclical application of conventional antimicrobials.

gamma-Aminobutyric acid type A receptors (GABARs) have long been implicated in mediating ethanol (EtOH) actions, but so far most of the reported recombinant GABAR combinations have shown EtOH responses only at fairly high concentrations >> or = 60 mM). We show that GABARs containing the delta-subunit, which are highly sensitive to gamma-aminobutyric acid, slowly inactivating, and thought to be located outside of synapses, are enhanced by EtOH at concentrations that are reached with moderate, social EtOH consumption. Reproducible ethanol enhancements occur at 3 mM, a concentration six times lower than the legal blood-alcohol intoxication (driving) limit in most states (0.08% wt/vol or 17.4 mM). GABARs responsive to these low EtOH concentrations require the GABAR delta-subunit, which is thought to be associated exclusively with alpha 4- and alpha 6-subunits in vivo, and the beta 3-subunit, which has recently been shown to be essential for the in vivo anesthetic actions of etomidate and propofol. GABARs containing beta 2-instead of beta 3-subunits in alpha 4 beta delta- and alpha 6 beta delta-receptor combinations are almost 10 times less sensitive to EtOH, with threshold enhancement at 30 mM. GABARs containing gamma 2-instead of delta-subunits with alpha 4 beta and alpha 6 beta are three times less sensitive to EtOH, with threshold responses at 100 mM, a concentration not usually reached with social EtOH consumption. These combined findings suggest that "extrasynaptic" delta-subunit-containing GABARs, but not their "synaptic" gamma-subunit-containing counterparts, are primary targets for EtOH.

The contribution of the NADPH phagocyte oxidase (phox) and inducible nitric oxide (NO) synthase (iNOS) to the antimicrobial activity of macrophages for Salmonella typhimurium was studied by using peritoneal phagocytes from C57BL/6, congenic gp91phox(-/)-, iNOS(-/)-, and doubly immunodeficient phox(-/)-iNOS(-/)- mice. The respiratory burst and NO radical (NO.) made distinct contributions to the anti-Salmonella activity of macrophages. NADPH oxidase-dependent killing is confined to the first few hours after phagocytosis, whereas iNOS contributes to both early and late phases of antibacterial activity. NO-derived species initially synergize with oxyradicals to kill S. typhimurium, and subsequently exert prolonged oxidase-independent bacteriostatic effects. Biochemical analyses show that early killing of Salmonella by macrophages coincides with an oxidative chemistry characterized by superoxide anion (O(2).(-)), hydrogen peroxide (H(2)O(2)), and peroxynitrite (ONOO(-)) production. However, immunofluorescence microscopy and killing assays using the scavenger uric acid suggest that peroxynitrite is not responsible for macrophage killing of wild-type S. typhimurium. Rapid oxidative bacterial killing is followed by a sustained period of nitrosative chemistry that limits bacterial growth. Interferon gamma appears to augment antibacterial activity predominantly by enhancing NO. production, although a small iNOS-independent effect was also observed. These findings demonstrate that macrophages kill Salmonella in a dynamic process that changes over time and requires the generation of both reactive oxidative and nitrosative species.

Resistance to drug treatment is an important hurdle in the therapy of many brain disorders, including brain cancer, epilepsy, schizophrenia, depression and infection of the brain with HIV. Consequently, there is a pressing need to develop new and more effective treatment strategies. Mechanisms of resistance that operate in cancer and infectious diseases might also be relevant in drug-resistant brain disorders. In particular, drug efflux transporters that are expressed at the blood-brain barrier limit the ability of many drugs to access the brain. There is increasing evidence that drug efflux transporters have an important role in drug-resistant brain disorders, and this information should allow more efficacious treatment strategies to be developed.

Carbon nanotubes focus the attention of many scientists because of their huge potential of industrial applications, but there is a paucity of information on the toxicological properties of this material. The aim of this experimental study was to characterize the biological reactivity of purified multi-wall carbon nanotubes in the rat lung and in vitro. Multi-wall carbon nanotubes (CNT) or ground CNT were administered intratracheally (0.5, 2 or 5 mg) to Sprague-Dawley rats and we estimated lung persistence, inflammation and fibrosis biochemically and histologically. CNT and ground CNT were still present in the lung after 60 days (80% and 40% of the lowest dose) and both induced inflammatory and fibrotic reactions. At 2 months, pulmonary lesions induced by CNT were characterized by the formation of collagen-rich granulomas protruding in the bronchial lumen, in association with alveolitis in the surrounding tissues. These lesions were caused by the accumulation of large CNT agglomerates in the airways. Ground CNT were better dispersed in the lung parenchyma and also induced inflammatory and fibrotic responses. Both CNT and ground CNT stimulated the production of TNF-alpha in the lung of treated animals. In vitro, ground CNT induced the overproduction of TNF-alpha by macrophages. These results suggest that carbon nanotubes are potentially toxic to humans and that strict industrial hygiene measures should to be taken to limit exposure during their manipulation.

The lumenal surface of the colonic epithelium is continually exposed to Gram-negative commensal bacteria and LPS. Recognition of LPS by Toll-like receptor (TLR)-4 results in proinflammatory gene expression in diverse cell types. Normally, however, commensal bacteria and their components do not elicit an inflammatory response from intestinal epithelial cells (IEC). The aim of this study is to understand the molecular mechanisms by which IEC limit chronic activation in the presence of LPS. Three IEC lines (Caco-2, T84, HT-29) were tested for their ability to activate an NF-kappaB reporter gene in response to purified, protein-free LPS. No IEC line responded to LPS, whereas human dermal microvessel endothelial cells (HMEC) did respond to LPS. IEC responded vigorously to IL-1beta in this assay, demonstrating that the IL-1 receptor signaling pathway shared by TLRs was intact. To determine the reason for LPS hyporesponsiveness in IEC, we examined the expression of TLR4 and MD-2, a critical coreceptor for TLR4 signaling. IEC expressed low levels of TLR4 compared with HMEC and none expressed MD-2. To determine whether the low level of TLR4 expression or absent MD-2 was responsible for the LPS signaling defect in IEC, the TLR4 or MD-2 gene was transiently expressed in IEC lines. Transient transfection of either gene individually was not sufficient to restore LPS signaling, but cotransfection of TLR4 and MD-2 in IEC led to synergistic activation of NF-kappaB and IL-8 reporter genes in response to LPS. We conclude that IEC limit dysregulated LPS signaling by down-regulating expression of MD-2 and TLR4. The remainder of the intracellular LPS signaling pathway is functionally intact.

The connectivity diagram of neocortical circuits is still unknown, and there are conflicting data as to whether cortical neurons are wired specifically or not. To investigate the basic structure of cortical microcircuits, we use a two-photon photostimulation technique that enables the systematic mapping of synaptic connections with single-cell resolution. We map the inhibitory connectivity between upper layers somatostatin-positive GABAergic interneurons and pyramidal cells in mouse frontal cortex. Most, and sometimes all, inhibitory neurons are locally connected to every sampled pyramidal cell. This dense inhibitory connectivity is found at both young and mature developmental ages. Inhibitory innervation of neighboring pyramidal cells is similar, regardless of whether they are connected among themselves or not. We conclude that local inhibitory connectivity is promiscuous, does not form subnetworks, and can approach the theoretical limit of a completely connected synaptic matrix.

Nuclear pore complexes permit rapid passage of cargoes bound to nuclear transport receptors, but otherwise suppress nucleocytoplasmic fluxes of inert macromolecules>>/=30 kilodaltons. To explain this selectivity, a sieve structure of the permeability barrier has been proposed that is created through reversible cross-linking between Phe and Gly (FG)-rich nucleoporin repeats. According to this model, nuclear transport receptors overcome the size limit of the sieve and catalyze their own nuclear pore-passage by a competitive disruption of adjacent inter-repeat contacts, which transiently opens adjoining meshes. Here, we found that phenylalanine-mediated inter-repeat interactions indeed cross-link FG-repeat domains into elastic and reversible hydrogels. Furthermore, we obtained evidence that such hydrogel formation is required for viability in yeast.

Cortical surface-based analysis of fMRI data has proven to be a useful method with several advantages over 3-dimensional volumetric analyses. Many of the statistical methods used in 3D analyses can be adapted for use with surface-based analyses. Operating within the framework of the FreeSurfer software package, we have implemented a surface-based version of the cluster size exclusion method used for multiple comparisons correction. Furthermore, we have a developed a new method for generating regions of interest on the cortical surface using a sliding threshold of cluster exclusion followed by cluster growth. Cluster size limits for multiple probability thresholds were estimated using random field theory and validated with Monte Carlo simulation. A prerequisite of RFT or cluster size simulation is an estimate of the smoothness of the data. In order to estimate the intrinsic smoothness of group analysis statistics, independent of true activations, we conducted a group analysis of simulated noise data sets. Because smoothing on a cortical surface mesh is typically implemented using an iterative method, rather than directly applying a Gaussian blurring kernel, it is also necessary to determine the width of the equivalent Gaussian blurring kernel as a function of smoothing steps. Iterative smoothing has previously been modeled as continuous heat diffusion, providing a theoretical basis for predicting the equivalent kernel width, but the predictions of the model were not empirically tested. We generated an empirical heat diffusion kernel width function by performing surface-based smoothing simulations and found a large disparity between the expected and actual kernel widths.

Excessive immune responses are detrimental to the host and negative feedback regulation is crucial for the maintenance of immune-system integrity. Recent studies have shown that phosphoinositide 3-kinase (PI3K) is an endogenous suppressor of interleukin-12 (IL-12) production triggered by Toll-like receptor (TLR) signaling and limits excessive Th1 polarization. Unlike IRAK-M (IL-1 receptor-associated kinase-M) and SOCS-1 (suppressor of cytokine signaling-1) that are induced by TLR signaling and function during the second or continuous exposure to stimulation, PI3K functions at the early phase of TLR signaling and modulates the magnitude of the primary activation. Thus, PI3K, IRAK-M and SOCS-1 have unique roles in the gate-keeping system, preventing excessive innate immune responses.

BACKGROUND

Patients with chronic hepatitis C virus (HCV) infection who have not had a response to therapy with peginterferon and ribavirin may benefit from the addition of multiple direct-acting antiviral agents to their treatment regimen.

METHODS

This open-label, phase 2a study included an exploratory cohort of 21 patients with chronic HCV genotype 1 infection who had not had a response to previous therapy (i.e., had not had ≥2 log(10) decline in HCV RNA after ≥12 weeks of treatment with peginterferon and ribavirin). We randomly assigned patients to receive the NS5A replication complex inhibitor daclatasvir (60 mg once daily) and the NS3 protease inhibitor asunaprevir (600 mg twice daily) alone (group A, 11 patients) or in combination with peginterferon alfa-2a and ribavirin (group B, 10 patients) for 24 weeks. The primary end point was the percentage of patients with a sustained virologic response 12 weeks after the end of the treatment period.

RESULTS

A total of 4 patients in group A (36%; 2 of 9 with HCV genotype 1a and 2 of 2 with genotype 1b) had a sustained virologic response at 12 weeks after treatment and also at 24 weeks after treatment.. Six patients (all with HCV genotype 1a) had viral breakthrough while receiving therapy, and resistance mutations to both antiviral agents were found in all cases; 1 patient had a viral response at the end of treatment but had a relapse after the treatment period. All 10 patients in group B had a sustained virologic response at 12 weeks after treatment, and 9 had a sustained virologic response at 24 weeks after treatment. Diarrhea was the most common adverse event in both groups. Six patients had transient elevations of alanine aminotransferase levels to more than 3 times the upper limit of the normal range.

CONCLUSIONS

This preliminary study involving patients with HCV genotype 1 infection who had not had a response to prior therapy showed that a sustained virologic response can be achieved with two direct-acting antiviral agents only. In addition, a high rate of sustained virologic response was achieved when the two direct-acting antiviral agents were combined with peginterferon alfa-2a and ribavirin. (Funded by Bristol-Myers Squibb; ClinicalTrials.gov number, NCT01012895.).

BACKGROUND

Current recommendations for initiation of antiretroviral therapy in patients infected with human immunodeficiency virus type 1 (HIV) are based on CD4 T-lymphocyte cell counts and plasma HIV RNA levels. The relative prognostic value of each marker following initiation of therapy has not been fully characterized.

OBJECTIVE

To describe rates of disease progression to death and AIDS or death among patients starting triple-drug antiretroviral therapy, stratified by baseline CD4 cell count and HIV RNA levels.

METHODS

Population-based analysis of 1219 antiretroviral therapy-naive HIV-positive men and women aged 18 years or older in British Columbia who initiated triple-drug therapy between August 1, 1996, and September 30, 1999.

METHODS

Cumulative mortality rates from the initiation of triple-drug antiretroviral therapy to September 30, 2000, determined using various CD4 cell and plasma HIV RNA thresholds.

RESULTS

As of September 30, 2000, 82 patients had died of AIDS-related causes, for a crude AIDS-related mortality rate of 6.7%. The product limit estimate (SE) of the cumulative mortality rate at 12 months was 2.9% (0.5%). In univariate analyses, a prior diagnosis of acquired immunodeficiency syndrome (AIDS), CD4 cell count, use of protease inhibitors, and HIV RNA level were associated with mortality. There was no difference in mortality by age or sex. Only CD4 cell count remained statistically significant in the multivariate analysis. After controlling for AIDS, protease inhibitor use, and plasma HIV RNA level at baseline, patients with CD4 cell counts of less than 50/microL were 6.67 (95% confidence interval [CI], 3.61-12.34) times and those with counts of 50/microL to 199/microL were 3.41 (95% CI, 1.93-6.03) times more likely to die than those with counts of at least 200/microL.

CONCLUSIONS

Our data demonstrate uniformly low rates of disease progression to death and AIDS or death among patients starting antiretroviral therapy with CD4 cell counts of at least 200/microL. In our study, disease progression to death and AIDS or death was clustered among patients starting therapy with CD4 cell counts less than 200/microL.