In vitro synergy and enhanced murine brain penetration of saquinavir coadministered with mefloquine.

Highly active antiretroviral therapy has substantially improved prognosis in human immunodeficiency virus (HIV). However, the integration of proviral DNA, development of viral resistance, and lack of permeability of drugs into sanctuary sites (e.g., brain and lymphocyte) are major limitations to current regimens. Previous studies have indicated that the antimalarial drug chloroquine (CQ) has antiviral efficacy and a synergism with HIV protease inhibitors. We have screened a panel of antimalarial compounds for activity against HIV-1 in vitro. A limited efficacy was observed for CQ, mefloquine (MQ), and mepacrine (MC). However, marked synergy was observed between MQ and saquinavir (SQV), but not CQ in U937 cells. Furthermore, enhancement of the antiviral activity of SQV and four other protease inhibitors (PIs) by MQ was observed in MT4 cells, indicating a class specific rather than a drug-specific phenomenon. We demonstrate that these observations are a result of inhibition of multiple drug efflux proteins by MQ and that MQ also displaces SQV from orosomucoid in vitro. Finally, coadministration of MQ and SQV in CD-1 mice dramatically altered the tissue distribution of SQV, resulting in a >3-fold and >2-fold increase in the tissue/blood ratio for brain and testis, respectively. This pharmacological enhancement of in vitro antiviral activity of PIs by MQ now warrants further examination in vivo

Bistability in Apoptosis by Receptor Clustering

Apoptosis is a highly regulated cell death mechanism involved in many physiological processes. A key component of extrinsically activated apoptosis is the death receptor Fas, which, on binding to its cognate ligand FasL, oligomerize to form the death-inducing signaling complex. Motivated by recent experimental data, we propose a mathematical model of death ligand-receptor dynamics where FasL acts as a clustering agent for Fas, which form locally stable signaling platforms through proximity-induced receptor interactions. Significantly, the model exhibits hysteresis, providing an upstream mechanism for bistability and robustness. At low receptor concentrations, the bistability is contingent on the trimerism of FasL. Moreover, irreversible bistability, representing a committed cell death decision, emerges at high concentrations, which may be achieved through receptor pre-association or localization onto membrane lipid rafts. Thus, our model provides a novel theory for these observed biological phenomena within the unified context of bistability. Importantly, as Fas interactions initiate the extrinsic apoptotic pathway, our model also suggests a mechanism by which cells may function as bistable life/death switches independently of any such dynamics in their downstream components. Our results highlight the role of death receptors in deciding cell fate and add to the signal processing capabilities attributed to receptor clustering.Comment: Accepted by PLoS Comput Bio

Central defect type partial ACL injury model on goat knees: the effect of infrapatellar fat pad excision

BACKGROUND: The mid-substance central defect injury has been used to investigate the primary healing capacity of the anterior cruciate ligament (ACL) in a goat model. The sagittal plane stability on this model has not been confirmed, and possible effects of fat pad excision on healing have not been evaluated. We hypothesize that excising the fat pad tissue results in poorer ligament healing as assessed histologically and decreased tensile strength of the healing ligament. We further hypothesize that the creation of a central defect does not affect sagittal plane knee stability. METHODS: A mid-substance central defect was created with a 4-mm arthroscopic punch in the ACLs of right knees of all the subjects through a medial mini-arthrotomy. Goats were assigned to groups based on whether the fat pad was preserved (group 1, n = 5) or excised completely (group 2, n = 5). The left knees served as controls in each goat. Histopathology of the defect area along with measurement of type I collagen in one goat from each group were performed at 10th week postoperatively. The remaining knees were evaluated biomechanically at the 12th week, by measuring anterior tibial translation (ATT) of the knee joints at 90° of flexion and testing tensile properties (ultimate tensile load (UTL), ultimate elongation (UE), stiffness (S), failure mode (FM)) of the femur-ACL-tibia complex. RESULTS AND DISCUSSION: Histopathology analysis revealed that the central defect area was fully filled macroscopically and microscopically. However, myxoid degeneration and fibrosis were observed in group 2 and increased collagen type I content was noted in group 2. There were no significant differences within and between groups in terms of ATT values (p = 0.715 and p = 0.149, respectively). There were no significance between or within groups in terms of ultimate tensile load and ultimate elongation; however, group 2 demonstrated greater stiffness than group 1 that was correlated with the fibrotic changes detected microscopically (p = 0.043). CONCLUSIONS: The central defect type injury model was confirmed to be biomechanically stable in a goat model. Resection of the fat pad was noted to negatively affect defect healing and increase ligament stiffness in the central defect injury model

Clinical Manifestations and Case Management of Ebola Haemorrhagic Fever caused by a newly identified virus strain, Bundibugyo, Uganda, 2007-2008

A confirmed Ebola haemorrhagic fever (EHF) outbreak in Bundibugyo, Uganda, November 2007-February 2008, was caused by a putative new species (Bundibugyo ebolavirus). It included 93 putative cases, 56 laboratory-confirmed cases, and 37 deaths (CFR = 25%). Study objectives are to describe clinical manifestations and case management for 26 hospitalised laboratory-confirmed EHF patients. Clinical findings are congruous with previously reported EHF infections. The most frequently experienced symptoms were non-bloody diarrhoea (81%), severe headache (81%), and asthenia (77%). Seven patients reported or were observed with haemorrhagic symptoms, six of whom died. Ebola care remains difficult due to the resource-poor setting of outbreaks and the infection-control procedures required. However, quality data collection is essential to evaluate case definitions and therapeutic interventions, and needs improvement in future epidemics. Organizations usually involved in EHF case management have a particular responsibility in this respect

"A calorie is a calorie" violates the second law of thermodynamics

The principle of "a calorie is a calorie," that weight change in hypocaloric diets is independent of macronutrient composition, is widely held in the popular and technical literature, and is frequently justified by appeal to the laws of thermodynamics. We review here some aspects of thermodynamics that bear on weight loss and the effect of macronutrient composition. The focus is the so-called metabolic advantage in low-carbohydrate diets – greater weight loss compared to isocaloric diets of different composition. Two laws of thermodynamics are relevant to the systems considered in nutrition and, whereas the first law is a conservation (of energy) law, the second is a dissipation law: something (negative entropy) is lost and therefore balance is not to be expected in diet interventions. Here, we propose that a misunderstanding of the second law accounts for the controversy about the role of macronutrient effect on weight loss and we review some aspects of elementary thermodynamics. We use data in the literature to show that thermogenesis is sufficient to predict metabolic advantage. Whereas homeostasis ensures balance under many conditions, as a general principle, "a calorie is a calorie" violates the second law of thermodynamics

MISHIMA - a new method for high speed multiple alignment of nucleotide sequences of bacterial genome scale data

<p>Abstract</p> <p>Background</p> <p>Large nucleotide sequence datasets are becoming increasingly common objects of comparison. Complete bacterial genomes are reported almost everyday. This creates challenges for developing new multiple sequence alignment methods. Conventional multiple alignment methods are based on pairwise alignment and/or progressive alignment techniques. These approaches have performance problems when the number of sequences is large and when dealing with genome scale sequences.</p> <p>Results</p> <p>We present a new method of multiple sequence alignment, called MISHIMA (Method for Inferring Sequence History In terms of Multiple Alignment), that does not depend on pairwise sequence comparison. A new algorithm is used to quickly find rare oligonucleotide sequences shared by all sequences. Divide and conquer approach is then applied to break the sequences into fragments that can be aligned independently by an external alignment program. These partial alignments are assembled together to form a complete alignment of the original sequences.</p> <p>Conclusions</p> <p>MISHIMA provides improved performance compared to the commonly used multiple alignment methods. As an example, six complete genome sequences of bacteria species <it>Helicobacter pylori </it>(about 1.7 Mb each) were successfully aligned in about 6 hours using a single PC.</p

Implementation of the CALM intervention for anxiety disorders: a qualitative study

<p>Abstract</p> <p>Background</p> <p>Investigators recently tested the effectiveness of a collaborative-care intervention for anxiety disorders: Coordinated Anxiety Learning and Management(CALM) []) in 17 primary care clinics around the United States. Investigators also conducted a qualitative process evaluation. Key research questions were as follows: (1) What were the facilitators/barriers to implementing CALM? (2) What were the facilitators/barriers to sustaining CALM after the study was completed?</p> <p>Methods</p> <p>Key informant interviews were conducted with 47 clinic staff members (18 primary care providers, 13 nurses, 8 clinic administrators, and 8 clinic staff) and 14 study-trained anxiety clinical specialists (ACSs) who coordinated the collaborative care and provided cognitive behavioral therapy. The interviews were semistructured and conducted by phone. Data were content analyzed with line-by-line analyses leading to the development and refinement of themes.</p> <p>Results</p> <p>Similar themes emerged across stakeholders. Important facilitators to implementation included the perception of "low burden" to implement, provider satisfaction with the intervention, and frequent provider interaction with ACSs. Barriers to implementation included variable provider interest in mental health, high rates of part-time providers in clinics, and high social stressors of lower socioeconomic-status patients interfering with adherence. Key sustainability facilitators were if a clinic had already incorporated collaborative care for another disorder and presence of onsite mental health staff. The main barrier to sustainability was funding for the ACS.</p> <p>Conclusions</p> <p>The CALM intervention was relatively easy to incorporate during the effectiveness trial, and satisfaction was generally high. Numerous implementation and sustainability barriers could limit the reach and impact of widespread adoption. Findings should be interpreted with the knowledge that the ACSs in this study were provided and trained by the study. Future research should explore uptake of CALM and similar interventions without the aid of an effectiveness trial.</p

The effect of acetaminophen (four grams a day for three consecutive days) on hepatic tests in alcoholic patients – a multicenter randomized study

Background: Hepatic failure has been associated with reported therapeutic use of acetaminophen by alcoholic patients. The highest risk period for alcoholic patients is immediately after discontinuation of alcohol intake. This period exhibits the largest increase in CYP2E1 induction and lowest glutathione levels. Our hypothesis was that common liver tests would be unaffected by administration of the maximum recommended daily dosage of acetaminophen for 3 consecutive days to newly-abstinent alcoholic subjects. Methods: Adult alcoholic subjects entering two alcohol detoxification centers were enrolled in a prospective double-blind, randomized, placebo-controlled trial. Subjects were randomized to acetaminophen, 4 g/day, or placebo for 3 consecutive days. The study had 95% probability of detecting a 15 IU/L difference in serum ALT. Results: A total of 443 subjects were enrolled: 308 (258 completed) received acetaminophen and 135 subjects (114 completed) received placebo. Study groups did not differ in demographics, alcohol consumption, nutritional status or baseline laboratory assessments. The peak mean ALT activity was 57 [plus or minus] 45 IU/L and 55 [plus or minus] 48 IU/L in the acetaminophen and placebo groups, respectively. Subgroup analyses for subjects presenting with an elevated ALT, subjects fulfilling a diagnosis of alcoholic hepatitis and subjects attaining a peak ALT greater than 200 IU/L showed no statistical difference between the acetaminophen and control groups. The one participant developing an increased international normalized ratio was in the placebo group. Conclusion: Alcoholic patients treated with the maximum recommended daily dose of acetaminophen for 3 consecutive days did not develop increases in serum transaminase or other measures of liver injury. Treatment of pain or fever for 3 days with acetaminophen appears safe in newly-abstinent alcoholic patients, such as those presenting for acute medical care.Funding for this study was provided by McNeil Consumer Healthcare to the Denver Health Authority, Denver, Colorado