The Challenge of Treating Biofilm-associated Bacterial Infections

Biofilm formation is a crucial step in the pathogenesis of many subacute and chronic bacterial infections, including foreign body-related infections. Biofilms are difficult to eradicate with conventional antimicrobial agents. Bacterial biofilms have several potential antimicrobial resistance mechanisms. Antimicrobial resistance mechanisms may act concurrently, and in some cases, synergistically. Persister cells play a major role in the tolerance of biofilm bacteria to antimicrobial agents. Understanding the mechanisms involved in biofilm-associated antimicrobial resistance is key to development of new therapeutic strategies.

Infections in solid-organ transplant recipients

Solid-organ transplantation is a therapeutic option for many human diseases. Infections are a major complication of solid-organ transplantation. All candidates should undergo a thorough infectious-disease screening prior to transplantation. There are three time frames, influenced by surgical factors, the level of immunosuppression, and environmental exposures, during which infections of specific types most frequently occur posttransplantation. Most infections during the first month are related to surgical complications. Opportunistic infections typically occur from the second to the sixth month. During the late posttransplant period (beyond 6 months), transplantation recipients suffer from the same infections seen in the general community. Opportunistic bacterial infections seen in transplant recipients include those caused by Legionella spp., Nocardia spp., Salmonella spp., and Listeria monocytogenes. Cytomegalovirus is the most common cause of viral infections. Herpes simplex virus, varicella-zoster virus, Epstein-Barr virus and others are also significant pathogens. Fungal infections, caused by both yeasts and mycelial fungi, are associated with the highest mortality rates. Mycobacterial, pneumocystis, and parasitic diseases may also occur.

Rubber-Thermoplastic Compositions. Part I. EPDM-Polypropylene Thermoplastic Vulcanizates

Thermoplastic elastomers are rubbery materials which can be fabricated by techniques usually associated with thermoplastic resins. Classical elastomers rely upon the crosslinked network, developed during vulcanization, to provide the retractive forces of rubber type elasticity. Thermoplastic elastomers contain rubber domains and resinous thermoplastic domains. The thermoplasticity results from the melting characteristics of the hard thermoplastic phase, while the rubber properties arise from the rubbery domains. Thermoplastic elastomers are, therefore, almost by definition, heterogeneous in their phase morphology. Such materials can be blends or block polymers. In the case of block polymers, the rubbery phase is not crosslinked chemically. However, hard or resinous phase domains occur as the hard segments of the block polymer which separate from the composition by agglomeration during cooling from the molten state. These domains act both as well-bonded reinforcing filler particles and as crosslinks. This is, of course, because the hard blocks are connected to the soft or rubbery segments by primary chemical bonds. In the case of the blend compositions, the hard and soft domains are separate polymeric species. However, there must be some form of interaction between the domains if useful properties are to be realized. Recently, uncured or partially cured EPDM rubber has been blended with polyolefin resin to make thermoplastic elastomer-like compositions. However, these compositions suffer deficiencies in performance as well as in certain aspects of fabricability. Only poor to fair performance at temperatures above 70°C in air or in oil has been achieved with the uncured to partially cured compositions. More recently, it has been found in our laboratories that fully cured EPDM compositions which are fabricable as thermoplastics can be prepared. Such compositions, referred to here as thermoplastic vulcanizates, have superior strength, high-temperature mechanical properties, hot oil and solvent resistance, better compression set, etc. This report outlines critical parameters associated with these unique materials.

Mucormycosis and entomophthoramycosis: a review of the clinical manifestations, diagnosis and treatment

The class Zygomycetes is divided into two orders, Mucorales and Entomophthorales. These two orders produce dramatically different infections. Genera from the order Mucorales (Rhizopus, Mucor, Rhizomucor, Absidia, Apophysomyces, Cunninghamella and Saksenaea) cause an angioinvasive infection called mucormycosis. Mucormycosis presents with rhino-orbito-cerebral, pulmonary, disseminated, cutaneous, or gastrointestinal involvement. Immunocompromising states such as haematological malignancy, bone marrow or peripheral blood stem cell transplantation, neutropenia, solid organ transplantation, diabetes mellitus with or without ketoacidosis, corticosteroids, and deferoxamine therapy for iron overload predispose patients to infection. Mucormycosis in immunocompetent hosts is rare, and is often related to trauma. Mortality rates can approach 100% depending on the patient's underlying disease and form of mucormycosis. Early diagnosis, along with treatment of the underlying medical condition, surgery, and an amphotericin B product are needed for a successful outcome. Genera from the order Entomophthorales produce a chronic subcutaneous infection called entomophthoramycosis in immunocompetent patients. This infection occurs in tropical and subtropical climates. The genus Basidiobolus typically produces a chronic subcutaneous infection of the thigh, buttock, and/or trunk. Rarely, it has been reported to involve the gastrointestinal tract. The genus Conidiobolus causes a chronic infection of the nasal submucosa and subcutaneous tissue of the nose and face. This paper will review the clinical manifestations, diagnosis and treatment of mucormycosis and entomophthoramycosis.

In vitro activities of posaconazole, fluconazole, itraconazole, voriconazole, and amphotericin B against a large collection of clinically important molds and yeasts

The in vitro activity of the novel triazole antifungal agent posaconazole (Noxafil; SCH 56592) was assessed in 45 laboratories against approximately 19,000 clinically important strains of yeasts and molds. The activity of posaconazole was compared with those of itraconazole, fluconazole, voriconazole, and amphotericin B against subsets of the isolates. Strains were tested utilizing Clinical and Laboratory Standards Institute broth microdilution methods using RPMI 1640 medium (except for amphotericin B, which was frequently tested in antibiotic medium 3). MICs were determined at the recommended endpoints and time intervals. Against all fungi in the database (22,850 MICs), the MIC(50) and MIC(90) values for posaconazole were 0.063 microg/ml and 1 mug/ml, respectively. MIC(90) values against all yeasts (18,351 MICs) and molds (4,499 MICs) were both 1 mug/ml. In comparative studies against subsets of the isolates, posaconazole was more active than, or within 1 dilution of, the comparator drugs itraconazole, fluconazole, voriconazole, and amphotericin B against approximately 7,000 isolates of Candida and Cryptococcus spp. Against all molds (1,702 MICs, including 1,423 MICs for Aspergillus isolates), posaconazole was more active than or equal to the comparator drugs in almost every category. Posaconazole was active against isolates of Candida and Aspergillus spp. that exhibit resistance to fluconazole, voriconazole, and amphotericin B and was much more active than the other triazoles against zygomycetes. Posaconazole exhibited potent antifungal activity against a wide variety of clinically important fungal pathogens and was frequently more active than other azoles and amphotericin B.

Fractures of the acetabulum in patients aged 60 years and older: an epidemiological and radiological study

Using a prospective database of 1309 displaced acetabular fractures gathered between 1980 and 2007, we calculated the annual mean age and annual incidence of elderly patients > 60 years of age presenting with these injuries. We compared the clinical details and patterns of fracture between patients > 60 years of age (study group) with those < 60 years (control group). We performed a detailed evaluation of the radiographs of the older group to determine the incidence of radiological characteristics which have been previously described as being associated with a poor patient outcome. In all, 235 patients were > 60 years of age and the remaining 1074 were < 60 years. The incidence of elderly patients with acetabular fractures increased by 2.4-fold between the first half of the study period and the second half (10% (62) vs 24% (174), p < 0.001). Fractures characterised by displacement of the anterior column were significantly more common in the elderly compared with the younger patients (64% (150) vs 43% (462), respectively, p < 0.001). Common radiological features of the fractures in the study group included a separate quadrilateral-plate component (50.8% (58)) and roof impaction (40% (46)) in the anterior fractures, and comminution (44% (30)) and marginal impaction (38% (26)) in posterior-wall fractures. The proportion of elderly patients presenting with acetabular fractures increased during the 27-year period. The older patients had a different distribution of fracture pattern than the younger patients, and often had radiological features which have been shown in other studies to be predictive of a poor outcome.

Calcium and cell cycle control

The cell division cycle of the early sea urchin embryo is basic. Nonetheless, it has control points in common with the yeast and mammalian cell cycles, at START, mitosis ENTRY and mitosis EXIT. Progression through each control point in sea urchins is triggered by transient increases in intracellular free calcium. The Cai transients control cell cycle progression by translational and post-translational regulation of the cell cycle control proteins pp34 and cyclin. The START Cai transient leads to phosphorylation of pp34 and cyclin synthesis. The mitosis ENTRY Cai transient triggers cyclin phosphorylation. The motosis EXIT transient causes destruction of phosphorylated cyclin. We compare cell cycle regulation by calcium in sea urchin embryos to cell cycle regulation in other eggs and oocytes and in mammalian cells.

Self-assembly of collagen fibers. Influence of fibrillar alignment and decorin on mechanical properties

Collagen is the primary structural element in extracellular matrices. In the form of fibers it acts to transmit forces, dissipate energy, and prevent premature mechanical failure in normal tissues. Deformation of collagen fibers involves molecular stretching and slippage, fibrillar slippage, and, ultimately, defibrillation. Our laboratory has developed a process for self-assembly of macroscopic collagen fibers that have structures and mechanical properties similar to rat tail tendon fibers. The purpose of this study is to determine the effects of subfibrillar orientation and decorin incorporation on the mechanical properties of collagen fibers. Self-assembled collagen fibers were stretched 0-50% before cross-linking and then characterized by microscopy and mechanical testing. Results of these studies indicate that fibrillar orientation, packing, and ultimate tensile strength can be increased by stretching. In addition, it is shown that decorin incorporation increases ultimate tensile strength of uncross-linked fibers. Based on the observed results it is hypothesized that decorin facilitates fibrillar slippage during deformation and thereby improves the tensile properties of collagen fibers.

A quantitative immunohistochemical study of macroglial cell development in the rat optic nerve: in vivo evidence for two distinct astrocyte lineages

We have shown previously that three antibodies--anti-galactocerebroside (GC), anti-glial fibrillary acidic protein (GFAP), and the A2B5 monoclonal antibody--can be used to help distinguish three classes of glial cells in the rat optic nerve: oligodendrocytes are GC+, GFAP-, almost all type-1 astrocytes are A2B5-, GFAP+, and almost all type-2 astrocytes are A2B5+, GFAP+. In the present study we have used these antibodies to examine the timing and sequence of the development of the three types of glial cells in vivo. We show that type-1 astrocytes first appear at embryonic Day 16 (E16), oligodendrocytes at birth (E21), and type-2 astrocytes between postnatal Days 7 and 10 (P7-10). Moreover, we demonstrate quantitatively that astrocytes in the optic nerve develop in two waves, with more than 95% of type-1 astrocytes developing before P15 and more than 95% of type-2 astrocytes developing after P15. Finally, we provide indirect evidence that type-2 astrocytes do not develop from type-1 astrocytes in vivo, supporting previous direct evidence that the two types of astrocytes develop from two serologically distinct precursor cells in vitro.

The DNA sequence and analysis of human chromosome 6

Chromosome 6 is a metacentric chromosome that constitutes about 6% of the human genome. The finished sequence comprises 166,880,988 base pairs, representing the largest chromosome sequenced so far. The entire sequence has been subjected to high-quality manual annotation, resulting in the evidence-supported identification of 1,557 genes and 633 pseudogenes. Here we report that at least 96% of the protein-coding genes have been identified, as assessed by multi-species comparative sequence analysis, and provide evidence for the presence of further, otherwise unsupported exons/genes. Among these are genes directly implicated in cancer, schizophrenia, autoimmunity and many other diseases. Chromosome 6 harbours the largest transfer RNA gene cluster in the genome; we show that this cluster co-localizes with a region of high transcriptional activity. Within the essential immune loci of the major histocompatibility complex, we find HLA-B to be the most polymorphic gene on chromosome 6 and in the human genome.

Early maternal and neonatal morbidity associated with operative delivery in second stage of labour: a cohort study

BACKGROUND

A frequent dilemma for obstetricians is how to keep morbidity to a minimum when faced with arrested progress at full dilatation of the cervix. Our aim was to examine maternal and neonatal morbidity associated with vaginal instrumental delivery in theatre and caesarean section, at full dilatation.

METHODS

We did a prospective cohort study of 393 women, who had term, singleton, liveborn, cephalic pregnancies requiring operative delivery in theatre at full dilatation for 1 year.

FINDINGS

Factors increasing the likelihood of caesarean section included maternal body-mass index greater than 30 (adjusted odds ratio 2.4, 95% CI 1.2-4.9), neonatal birthweight greater than 4.0 kg (2.3, 1.3-3.8), and occipitoposterior position (2.5, 1.6-3.9). Women undergoing caesarean section were more likely to have a major haemorrhage (>1 L; 2.8, 1.1-7.6) and extended hospital stay (>/=6 days; 3.5, 1.6-7.6) than those with vaginal delivery. Babies delivered by caesarean section were more likely to require admission for intensive care (2.6, 1.2-6.0) but less likely to have trauma (0.4, 0.2-0.7) than babies delivered by forceps. Overall neonatal morbidity was low, but a few babies in each group had serious complications (serious trauma, eight vs three; sepsis, six vs 13; and jaundice, ten vs 12 after vaginal delivery and caesarean section, respectively). Major haemorrhage was less likely after delivery by a skilled obstetrician (0.5, 0.3-0.9).

INTERPRETATION

The data lend support to an aim to deliver women vaginally, unless there are clear signs of cephalopelvic disproportion, and underline the importance of skilled obstetricians supervising complex operative deliveries.

Multicenter phase II trial of weekly paclitaxel in women with metastatic breast cancer

PURPOSE

We evaluated the safety and efficacy of weekly paclitaxel therapy in women with metastatic breast cancer in a phase II multicenter trial. Entry criteria were relatively liberal to reflect the heterogeneity of metastatic breast cancer in clinical practice.

PATIENTS AND METHODS

Patients had histologically confirmed and measurable metastatic breast cancer. Up to two prior chemotherapy regimens for metastatic disease, including prior therapy with anthracyclines and taxanes and prior high-dose therapy, were allowed. Paclitaxel 80 mg/m(2) was administered weekly for 4 weeks per 4-week cycle.

RESULTS

We enrolled 212 patients; 211 were assessable for toxicity and 177 were assessable for response. Ninety percent of patients had received prior chemotherapy (adjuvant, metastatic, or both), 46% of patients had three or more involved metastatic sites, and 60% of patients had visceral-dominant disease. Responses were documented on two occasions and were independently reviewed. The overall response rate (complete plus partial response) was 21.5% (95% confidence interval, 15.4% to 27.5%), with 41.8% of patients having disease stabilization. Median time to progression was 4.7 months, and overall survival in all 212 patients enrolled was 12.8 months. Therapy was well tolerated, with a 15% incidence of grade 3/4 hematologic toxicity and a 9% incidence of grade 3 neurotoxicity; other serious toxicities were rare. The response rate and toxicity profile in the 34% of patients > or = 65 years of age were similar to that of younger patients.

CONCLUSION

Weekly paclitaxel therapy was well tolerated and demonstrated reasonable activity in this relatively heavily pretreated population with advanced disease. Further study of weekly paclitaxel in combination therapy is warranted.

Distribution of mRNAs encoding the peroxisome proliferator-activated receptor alpha, beta, and gamma and the retinoid X receptor alpha, beta, and gamma in rat central nervous system

We report the isolation, by RT-PCR, of partial cDNAs encoding the rat peroxisome proliferator-activated receptor (PPAR) isoforms PPAR alpha, PPAR beta, and PPAR gamma and the rat retinoid X receptor (RXR) isoforms RXR alpha, RXR beta, and RXR gamma. These cDNAs were used to generate antisense RNA probes to permit analysis, by the highly sensitive and discriminatory RNase protection assay, of the corresponding mRNAs in rat brain regions during development. PPAR alpha, PPAR beta, RXR alpha, and RXR beta mRNAs are ubiquitously present in different brain regions during development, PPAR gamma mRNA is essentially undetectable, and RXR gamma mRNA is principally localised to cortex. We demonstrate, for the first time, the presence of PPAR and RXR mRNAs in primary cultures of neonatal meningeal fibroblasts, cerebellar granule neurons (CGNs), and cortical and cerebellar astrocytes and in primary cultures of adult cortical astrocytes. PPAR alpha, PPAR beta, RXR alpha, and RXR beta mRNAs are present in all cell types, albeit that PPAR alpha and RXR alpha mRNAs are at levels near the limit of detection in CGNs. PPAR gamma mRNA is expressed at low levels in most cell types but is present at levels similar to those of PPAR alpha mRNA in adult astrocytes. RXR gamma mRNA is present either at low levels, or below the level of detection of the assay, for all cell types studied.

Simvastatin induces regression of cardiac hypertrophy and fibrosis and improves cardiac function in a transgenic rabbit model of human hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy is a genetic disease characterized by cardiac hypertrophy, myocyte disarray, interstitial fibrosis, and left ventricular (LV) dysfunction. We have proposed that hypertrophy and fibrosis, the major determinants of mortality and morbidity, are potentially reversible. We tested this hypothesis in beta-myosin heavy chain-Q(403) transgenic rabbits.

METHODS AND RESULTS

We randomized 24 beta-myosin heavy chain-Q(403) rabbits to treatment with either a placebo or simvastatin (5 mg. kg(-1). d(-1)) for 12 weeks and included 12 nontransgenic controls. We performed 2D and Doppler echocardiography and tissue Doppler imaging before and after treatment. Demographic data were similar among the groups. Baseline mean LV mass and interventricular septal thickness in nontransgenic, placebo, and simvastatin groups were 3.9+/-0.7, 6.2+/-2.0, and 7.5+/-2.1 g (P<0.001) and 2.2+/-0.2, 3.1+/-0.5, and 3.3+/-0.5 mm (P=0.002), respectively. Simvastatin reduced LV mass by 37%, interventricular septal thickness by 21%, and posterior wall thickness by 13%. Doppler indices of LV filling pressure were improved. Collagen volume fraction was reduced by 44% (P<0.001). Disarray was unchanged. Levels of activated extracellular signal-regulated kinase (ERK) 1/2 were increased in the placebo group and were less than normal in the simvastatin group. Levels of activated and total p38, Jun N-terminal kinase, p70S6 kinase, Ras, Rac, and RhoA and the membrane association of Ras, RhoA, and Rac1 were unchanged.

CONCLUSIONS

Simvastatin induced the regression of hypertrophy and fibrosis, improved cardiac function, and reduced ERK1/2 activity in the beta-myosin heavy chain-Q(403) rabbits. These findings highlight the need for clinical trials to determine the effects of simvastatin on cardiac hypertrophy, fibrosis, and dysfunction in humans with hypertrophic cardiomyopathy and heart failure.

Luminescent oxygen channeling assay (LOCI): sensitive, broadly applicable homogeneous immunoassay method

Luminescent oxygen channeling assay (LOCI) is a homogeneous immunoassay method capable of rapid, quantitative determination of a wide range of analytes--including high and very low concentrations of large and small molecules, free (unbound) drugs, DNA, and specific IgM. Assays have been carried out in serum and in lysed blood. Reliable detection of 1.25 microU/L thyrotropin (TSH) and 5 ng/L hepatitis B surface antigen (HBsAg) corresponds to detection limits approximately 3- and approximately 20-fold lower, respectively, than those of the best commercially available assays. An assay of chorionic gonadotropin is capable of quantification over a 10(6)-fold range of concentrations without a biphasic response. Latex particle pairs are formed in the assay through specific binding interactions by sequentially combining the sample and two reagents. One particle contains a photosensitizer, the other a chemiluminescer. Irradiation causes photosensitized formation of singlet oxygen, which migrates to a bound particle and activates the chemiluminescer, thereby initiating a delayed luminescence emission. Assay times range from 1 to 25 min.

2020 European guideline on the management of syphilis

The 2020 edition of the European guideline on the management of syphilis is an update of the 2014 edition. Main modifications and updates include: -The ongoing epidemics of early syphilis in Europe, particularly in men who have sex with men (MSM) -The development of dual treponemal and non-treponemal point-of-care (POC) tests -The progress in non-treponemal test (NTT) automatization -The regular episodic shortage of benzathine penicillin G (BPG) in some European countries -The exclusion of azithromycin as an alternative treatment at any stage of syphilis -The pre-exposure or immediate post-exposure prophylaxis with doxycycline in populations at high risk of acquiring syphilis.

Rubber-Thermoplastic Compositions. Part VIII. Nitrile Rubber Polyolefin Blends with Technological Compatibilization

The results of this work suggest a practical route to hot-oil-resistant thermoplastic elastomers based on NBR and a polyolefin resin (such as polypropylene). Although these two types of polymer are normally grossly incompatible with each other, a melt-mixed blend thereof is technologically improved by the presence of a small amount of a compatibilizing block copolymer which contains both polar and nonpolar segments. Ideally, the block copolymer should contain molecular segments of the types of polymers to be compatibilized. The compatibilizing block (graft) copolymer can form in situ during melt-mixing. Dynamic vulcanization (during melt-mixing) of a compatibilized NBR-polypropylene blend produces a thermoplastic elastomer with mechanical properties about as good as those of a corresponding composition of EPDM and polypropylene (two polymers which are nearly mutually compatible in a thermodynamic sense). The compatibilizing NBR-polypropylene graft copolymer might act by reducing (molten-state) interfacial tension at the NBR-polypropylene interface and also by increasing the interfacial adhesion in the “solidified-state” composition during its use. The hot-oil resistance of the compatibilized NBR-polypropylene thermoplastic vulcanizates is excellent. Also, the NBR-polypropylene compositions can be blended with thermoplastic vulcanizates based on EPDM and polypropylene to obtain thermoplastic elastomeric compositions which exhibit both good hot oil resistance and low temperature brittleness characteristics.

UK Consensus on Normal Tissue Dose Constraints for Stereotactic Radiotherapy

Six UK studies investigating stereotactic ablative radiotherapy (SABR) are currently open. Many of these involve the treatment of oligometastatic disease at different locations in the body. Members of all the trial management groups collaborated to generate a consensus document on appropriate organ at risk dose constraints. Values from existing but older reviews were updated using data from current studies. It is hoped that this unified approach will facilitate standardised implementation of SABR across the UK and will allow meaningful toxicity comparisons between SABR studies and internationally.

Reticulated platelets and uninhibited COX-1 and COX-2 decrease the antiplatelet effects of aspirin

BACKGROUND

The mechanisms for the variability in antiplatelet effects of aspirin are unclear. Immature (reticulated) platelets may modulate the antiplatelet effects of aspirin through uninhibited cyclooxygenase (COX)-1 and COX-2.

OBJECTIVES

To evaluate the role of reticulated platelets in the antiplatelet effects of aspirin.

METHODS

Sixty healthy volunteers had platelet studies performed before and 24 h after a single 325-mg dose of aspirin. Platelet studies included light transmission aggregometry; P-selectin and integrin alpha(IIb)beta(3) expression, and serum thromboxane B(2) (TxB(2)) levels. Reticulated platelets and platelet COX-2 expression were measured using flow cytometry.

RESULTS

Subjects were divided into tertiles based on the percentage of reticulated platelets in whole blood. Baseline platelet aggregation to 1 microg mL(-1) collagen, and postaspirin aggregations to 5 microm and 20 microm ADP and collagen, were greater in the upper than in the lower tertile of reticulated platelets. Stimulated P-selectin and integrin alpha(IIb)beta(3) expression were also higher in the upper tertile both before and after aspirin. Platelet COX-2 expression was detected in 12 +/- 7% (n = 10) of platelets in the upper tertile, and in 7 +/- 3% (n = 12) of platelets in the lower two tertiles (P = 0.03). Postaspirin serum TxB(2) levels were higher in the upper (5.5 +/- 4 ng mL(-1)) than in the lower tertile (3.2 +/- 2.5 ng mL(-1), P = 0.03), and decreased even further with ex vivo additional COX-1 and COX-2 inhibition. The incidence of aspirin resistance (>or= 70% platelet aggregation to 5 microm ADP) was significantly higher in the upper tertile (45%) than in the lower tertile (5%, P < 0.0001).

CONCLUSIONS

Reticulated platelets are associated with diminished antiplatelet effects of aspirin and increased aspirin resistance, possibly because of increased reactivity, and uninhibited COX-1 and COX-2 activity.

Interaction of Sirt3 with OGG1 contributes to repair of mitochondrial DNA and protects from apoptotic cell death under oxidative stress

Sirtuin 3 (Sirt3), a major mitochondrial NAD(+)-dependent deacetylase, targets various mitochondrial proteins for lysine deacetylation and regulates important cellular functions such as energy metabolism, aging, and stress response. In this study, we identified the human 8-oxoguanine-DNA glycosylase 1 (OGG1), a DNA repair enzyme that excises 7,8-dihydro-8-oxoguanine (8-oxoG) from damaged genome, as a new target protein for Sirt3. We found that Sirt3 physically associated with OGG1 and deacetylated this DNA glycosylase and that deacetylation by Sirt3 prevented the degradation of the OGG1 protein and controlled its incision activity. We further showed that regulation of the acetylation and turnover of OGG1 by Sirt3 played a critical role in repairing mitochondrial DNA (mtDNA) damage, protecting mitochondrial integrity, and preventing apoptotic cell death under oxidative stress. We observed that following ionizing radiation, human tumor cells with silencing of Sirt3 expression exhibited deteriorated oxidative damage of mtDNA, as measured by the accumulation of 8-oxoG and 4977 common deletion, and showed more severe mitochondrial dysfunction and underwent greater apoptosis in comparison with the cells without silencing of Sirt3 expression. The results reported here not only reveal a new function and mechanism for Sirt3 in defending the mitochondrial genome against oxidative damage and protecting from the genotoxic stress-induced apoptotic cell death but also provide evidence supporting a new mtDNA repair pathway.

Culture with BACTEC Peds Plus/F bottle compared with conventional methods for detection of bacteria in synovial fluid

An evaluation was undertaken to determine the utility of the BACTEC Peds Plus/F bottle and the BACTEC 9240 instrument (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) for the detection of clinically significant microorganisms in synovial fluid specimens. The Peds Plus/F bottle was used because in our laboratory the quantity of synovial fluid available for culture is frequently in the range of 0.5 to 3.0 ml. The culture results obtained with the Peds Plus/F bottle were compared to those obtained by a conventional agar plate method for a total of 805 synovial fluid specimens. Microbial growth was produced by 74 cultures (9.2%) from 60 patients, yielding a total of 77 microorganisms. Organisms were classified as pathogens (n = 62), contaminants (n = 12), or indeterminate (n = 3) on the basis of a review of the patients' medical histories. Culture using BACTEC Peds Plus/F bottle detected statistically significantly more pathogens overall (62 versus 51 pathogens [P = 0.001]) and statistically fewer contaminants overall (1 versus 11 contaminants [P = 0.006]) than culture by the agar plate method. These results indicate the superior performance of the BACTEC Peds Plus/F bottle over the conventional agar plate method for the detection of clinically significant microorganisms from synovial fluid specimens.

Addition of angiotensin II receptor blockade to maximal angiotensin-converting enzyme inhibition improves exercise capacity in patients with severe congestive heart failure

BACKGROUND

Incomplete suppression of the renin-angiotensin system during long-term ACE inhibition may contribute to symptomatic deterioration in patients with severe congestive heart failure (CHF). Combined angiotensin II type I (AT1) receptor blockade and ACE inhibition more completely suppresses the activated renin-angiotensin system than either intervention alone in sodium-depleted normal individuals. Whether AT1 receptor blockade with losartan improves exercise capacity in patients with severe CHF already treated with ACE inhibitors is unknown.

METHODS AND RESULTS

Thirty-three patients with severe CHF despite treatment with maximally recommended or tolerated doses of ACE inhibitors were randomized 1:1 to receive 50 mg/d losartan or placebo for 6 months in addition to standard therapy in a multicenter, double-blind trial. Peak aerobic capacity (V(O2)) during symptom-limited treadmill exercise and NYHA functional class were determined at baseline and after 3 and 6 months of double-blind therapy. Peak V(O2) at baseline and after 3 and 6 months were 13.5+/-0.6, 15.1+/-1.0, and 15.7+/-1.1 mL. kg-1. min-1, respectively, in patients receiving losartan and 14.1+/-0.6, 14.3+/-0.9, and 13.6+/-1.1 mL. kg-1. min-1, respectively, in patients receiving placebo (P<0.02 for treatment group-by-time interaction). Functional class improved by at least one NYHA class in 9 of 16 patients receiving losartan and 1 of 17 patients receiving placebo.

CONCLUSIONS

Losartan enhances peak exercise capacity and alleviates symptoms in patients with CHF who are severely symptomatic despite treatment with maximally recommended or tolerated doses of ACE inhibitors.