Healthcare-worker-associated outbreak of Panton-Valentine-leukocidin-producing meticillin-sensitive Staphylococcus aureus in a large neonatal unit in London: successful targeted suppression therapy following failure of mass suppression therapy.

BACKGROUND: Staphylococcus aureus is a leading cause of healthcare-associated infection, and outbreaks have been associated with neonatal units and colonization of healthcare workers. AIM: To describe an outbreak of Panton-Valentine-leukocidin-producing meticillin-sensitive Staphylococcus aureus (PVL-MSSA) in a neonatal intensive care unit. METHODS: Multi-disciplinary outbreak control investigation. RESULTS: Over a period of 16 months, seven neonates were identified as positive for PVL-MSSA. Isolates were identified in blood cultures (two patients), nasopharyngeal aspirate (one patient) and rectal screening swabs (four patients). Epidemiological and whole-genome sequencing data suggested a long-term carrier as the most likely source. Despite two rounds of mass suppression therapy of staff, using chlorhexidine initially followed by octenidine-based regimens, positive patients continued to be identified. Staff screening subsequently identified one healthcare worker colonized with the outbreak strain of PVL-MSSA who underwent enhanced screening and further suppression therapy. No further cases have been identified to date. Compliance with mass suppression therapy was >95% and a post-administration staff satisfaction survey showed that the majority of staff agreed with the steps taken, with low rates of adverse reactions. CONCLUSION: S. aureus outbreaks are commonly associated with colonization of healthcare workers, and are challenging to manage within environments such as neonatal units. This study highlights the utility of whole-genome sequencing in identifying and mapping an outbreak. It is recommended that targeted staff screening should be considered early in similar outbreaks. In this setting, mass suppression therapy was not an effective strategy despite a high level of staff engagement and compliance.

Molecular patterns of response and treatment failure after frontline venetoclax combinations in older patients with AML.

The BCL-2 inhibitor venetoclax combined with hypomethylating agents or low-dose cytarabine represents an important new therapy for older or unfit patients with acute myeloid leukemia (AML). We analyzed 81 patients receiving these venetoclax-based combinations to identify molecular correlates of durable remission, response followed by relapse (adaptive resistance), or refractory disease (primary resistance). High response rates and durable remissions were typically associated with NPM1 or IDH2 mutations, with prolonged molecular remissions prevalent for NPM1 mutations. Primary and adaptive resistance to venetoclax-based combinations was most commonly characterized by acquisition or enrichment of clones activating signaling pathways such as FLT3 or RAS or biallelically perturbing TP53. Single-cell studies highlighted the polyclonal nature of intratumoral resistance mechanisms in some cases. Among cases that were primary refractory, we identified heterogeneous and sometimes divergent interval changes in leukemic clones within a single cycle of therapy, highlighting the dynamic and rapid occurrence of therapeutic selection in AML. In functional studies, FLT3 internal tandem duplication gain or TP53 loss conferred cross-resistance to both venetoclax and cytotoxic-based therapies. Collectively, we highlight molecular determinants of outcome with clinical relevance to patients with AML receiving venetoclax-based combination therapies.

Vitamin D status and insulin sensitivity are novel predictors of resting metabolic rate: a cross-sectional analysis in Australian adults.

PURPOSE: Resting metabolic rate (RMR) accounts for two-thirds of the total energy expenditure in sedentary individuals. After accounting for traditional factors, there still remains a considerable unexplained variance in RMR. There is a pandemic of obesity and metabolic syndrome (MetS) which coexists with a high prevalence of vitamin D insufficiency. The aim of this study was to evaluate the potential effects of vitamin D status, insulin sensitivity (IS) and the metabolic syndrome (MetS) on RMR in Australian adults. METHODS: RMR, respiratory quotient (RQ), McAuley's insulin sensitivity index, fat mass (FM), fat-free mass (FFM) and vitamin D status were assessed in Australian adults. The presence of MetS was evaluated by current standard criteria. Predictors of RMR were examined through multiple linear regression based on stepwise and backward regression approaches with attention to multi-collinearity. All analyses were conducted on SPSS version 21. RESULTS: One hundred and twenty-seven participants (45 men, 82 women), aged 53.4 ± 11.7 years and BMI 31.9 ± 5.2 kg/m(2), were included. Forty-one subjects were insufficient in vitamin D status (<50 nmol/L), and 75 participants had the MetS. A parsimonious regression model explained 85.8 % of RMR and was given by: RMR (kJ/d) = 1931 + 83.5 × FFM (kg) + 29.5 × FM (kg) + 5.65 × 25(OH)D (nmol/L) - 17.6 × age (years) - 57.51 × IS. CONCLUSION: Vitamin D status and IS are novel independent predictors of RMR in adults. Future studies could validate a causal role for these factors in human energy metabolism.

Dual epigenetic targeting with panobinostat and azacitidine in acute myeloid leukemia and high-risk myelodysplastic syndrome.

Therapeutic options are limited for elderly patients with acute myeloid leukemia (AML). A phase Ib/II study was undertaken to evaluate the maximum-tolerated dose (MTD) and preliminary efficacy of the pan-histone deacetylase inhibitor panobinostat (LBH589) in combination with azacitidine in patients with AML or high-risk myelodysplastic syndrome (MDS) naïve to intensive chemotherapy. Thirty-nine patients (AML=29, MDS=10) received azacitidine 75 mg/m(2) subcutaneously (days 1-5) and oral panobinostat (starting on day 5, thrice weekly for seven doses) in 28-day cycles until toxicity or disease progression. Dose-limiting toxicities during the phase Ib stage were observed in 0/4 patients receiving 10 mg panobinostat, in 1/7 patients (fatigue) receiving 20 mg, in 1/6 patients (fatigue) receiving 30 mg and in 4/5 patients (fatigue, syncope, hyponatremia and somnolence) receiving 40 mg. In phase II, an additional 17 patients received panobinostat at a MTD of 30 mg. The overall response rate (ORR=CR+CRi+PR) in patients with AML was 31% (9/29) and that in patients with MDS was 50% (5/10). After a median follow-up of 13 months, the median overall survival was 8 and 16 months in patients with AML and MDS, respectively. Increased histone H3 and H4 acetylation was a useful early biomarker of clinical response. Combining panobinostat with azacitidine was tolerable and clinically active in high-risk MDS/AML patients, warranting further exploration.

Does mating behaviour affect connectivity in marine fishes? Comparative population genetics of two protogynous groupers (Family Serranidae).

Pelagic larval duration (PLD) has been hypothesized to be the primary predictor of connectivity in marine fishes; however, few studies have examined the effects that adult reproductive behaviour may have on realized dispersal. We assessed gene flow (connectivity) by documenting variation in microsatellites and mitochondrial DNA sequences in two protogynous species of groupers, the aggregate spawning red hind, Epinephelus guttatus, and the single-male, harem-spawning coney, Cephalopholis fulva, to ask whether reproductive strategy affects connectivity. Samples of both species were obtained from waters off three islands (Puerto Rico, St. Thomas and St. Croix) in the Caribbean Sea. Despite the notion that aggregate spawning of red hind may facilitate larval retention, stronger signals of population structure were detected in the harem-spawning coney. Heterogeneity and/or inferred barriers, based on microsatellites, involved St. Croix (red hind and coney) and the west coast of Puerto Rico (coney). Heterogeneity and/or inferred barriers, based on mitochondrial DNA, involved St. Croix (coney only). Genetic divergence in both species was stronger for microsatellites than for mitochondrial DNA, suggesting sex-biased dispersal in both species. Long-term migration rates, based on microsatellites, indicated asymmetric gene flow for both species in the same direction as mean surface currents in the region. Red hind had higher levels of variation in microsatellites and lower levels of variation in mitochondrial DNA. Long-term effective size and effective number of breeders were greater for red hind; estimates of θ(f) , a proxy for long-term effective female size, were the same in both species. Patterns of gene flow in both species appear to stem in part from shared aspects of larval and adult biology, local bathymetry and surface current patterns. Differences in connectivity and levels of genetic variation between the species, however, likely stem from differences in behaviour related to reproductive strategy.

Genetic variation in SH3-domain GRB2-like (endophilin)-interacting protein 1 has a major impact on fat mass.

OBJECTIVE: The SH3-domain GRB2-like (endophilin)-interacting protein 1 (SGIP1) gene has been shown to be differentially expressed in the hypothalamus of lean versus obese Israeli sand rats (Psammomys obesus), and is suspected of having a role in regulating food intake. The purpose of this study was to assess the role of genetic variation in SGIP1 in human disease. SUBJECTS: We performed single-nucleotide polymorphism (SNP) genotyping in a large family pedigree cohort from the island of Mauritius. The Mauritius Family Study (MFS) consists of 400 individuals from 24 Indo-Mauritian families recruited from the genetically homogeneous population of Mauritius. We measured markers of the metabolic syndrome, including diabetes and obesity-related phenotypes such as fasting plasma glucose, waist:hip ratio, body mass index and fat mass. RESULTS: Statistical genetic analysis revealed associations between SGIP1 polymorphisms and fat mass (in kilograms) as measured by bioimpedance. SNP genotyping identified associations between several genetic variants and fat mass, with the strongest association for rs2146905 (P=4.7 × 10(-5)). A strong allelic effect was noted for several SNPs where fat mass was reduced by up to 9.4% for individuals homozygous for the minor allele. CONCLUSIONS: Our results show association between genetic variants in SGIP1 and fat mass. We provide evidence that variation in SGIP1 is a potentially important determinant of obesity-related traits in humans.

Vitamin D and parathyroid hormone in insulin resistance of abdominal obesity: cause or effect?

The objective was to examine whether there were causal links between vitamin D status, parathyroid hormone, insulin resistance (IR)/insulin sensitivity (IS) and the metabolic syndrome (MS). A total of 72 Caucasian men and women, aged 55.7 ± 7.57 years, with body mass index 33.4 ± 4.02 kg/m(2) and abdominal obesity, were assessed for IR/IS based on three commonly used indices before and after 12 weeks of supervised weight loss. During weight stability, though both lower intact parathyroid hormone (iPTH) and higher vitamin D were independently associated with greater IS/lower IR, this was consistent for iPTH across the surrogate measures tested. Higher iPTH, but not lower vitamin D, increased the risk of MS after adjustment for IR/IS. Weight loss resulted in significant reductions in percent fat (-2.83 ± 2.20%), waist (-9.26 ± 5.11 cm), improvements in all IS indices, reductions in MS and iPTH (-0.28 ± 1.17 pmol/l), but no increase in vitamin D (+2.19 ± 12.17 nmol/l). Following weight loss, ΔiPTH either predicted change in IR/IS or contributed to their variance by 4.1-8.9%. On adjustment for IR/IS, higher ΔiPTH did not significantly predict MS after weight loss, though the odds ratios for the effect were sizeable. The data are suggestive of an intrinsic inverse relationship between iPTH and IS in abdominally obese individuals, independent of vitamin D. There remains the possibility of a direct relationship between iPTH and MS.

Accuracy of perturbative master equations.

We consider open quantum systems with dynamics described by master equations that have perturbative expansions in the system-environment interaction. We show that, contrary to intuition, full-time solutions of order-2n accuracy require an order-(2n+2) master equation. We give two examples of such inaccuracies in the solutions to an order-2n master equation: order-2n inaccuracies in the steady state of the system and order-2n positivity violations. We show how these arise in a specific example for which exact solutions are available. This result has a wide-ranging impact on the validity of coupling (or friction) sensitive results derived from second-order convolutionless, Nakajima-Zwanzig, Redfield, and Born-Markov master equations.

Bcl-2 and ß1-integrin predict survival in a tissue microarray of small cell lung cancer.

INTRODUCTION: Survival in small cell lung cancer (SCLC) is limited by the development of chemoresistance. Factors associated with chemoresistance in vitro have been difficult to validate in vivo. Both Bcl-2 and ß(1)-integrin have been identified as in vitro chemoresistance factors in SCLC but their importance in patients remains uncertain. Tissue microarrays (TMAs) are useful to validate biomarkers but no large TMA exists for SCLC. We designed an SCLC TMA to study potential biomarkers of prognosis and then used it to clarify the role of both Bcl-2 and ß(1)-integrin in SCLC. METHODS: A TMA was constructed consisting of 184 cases of SCLC and stained for expression of Bcl-2 and ß(1)-integrin. The slides were scored and the role of the proteins in survival was determined using Cox regression analysis. A meta-analysis of the role of Bcl-2 expression in SCLC prognosis was performed based on published results. RESULTS: Both proteins were expressed at high levels in the SCLC cases. For Bcl-2 (n=140), the hazard ratio for death if the staining was weak in intensity was 0.55 (0.33-0.94, P=0.03) and for ß(1)-integrin (n=151) was 0.60 (0.39-0.92, P=0.02). The meta-analysis showed an overall hazard ratio for low expression of Bcl-2 of 0.91(0.74-1.09). CONCLUSIONS: Both Bcl-2 and ß(1)-integrin are independent prognostic factors in SCLC in this cohort although further validation is required to confirm their importance. A TMA of SCLC cases is feasible but challenging and an important tool for biomarker validation.

A regulator gene for acetate utilisation from Neurospora crassa.

The Neurospora crassa homologue of the Aspergillus nidulans regulatory gene facB has been cloned. The gene encodes a putative transcriptional activator of 865 amino acids that contains a DNA-binding domain with a Zn(II)(2)Cys(6) binuclear cluster, a linker region and a leucine zipper-like heptad repeat. Two internal amino acid sequences are identical to peptide sequences determined from proteolytic fragments of a DNA-binding protein complex specific for genes involved in acetate utilisation and expressed in acetate-induced mycelia of N. crassa. Recombinant expression of the predicted DNA-binding domain demonstrates that it is capable of independent recognition of a subset of the promoter sequences that bind the protein complex from N. crassa. A duplication-induced mutation in the corresponding gene results in an acetate non-utilising phenotype that is characterised by inefficient induction of the enzymes required for acetate utilisation. The new gene does not fall into any existing complementation group and has been designated acu-15.

Short-term high-fat diet alters substrate utilization during exercise but not glucose tolerance in highly trained athletes.

We determined the effect of a high-fat diet and carbohydrate (CHO) restoration on substrate oxidation and glucose tolerance in 7 competitive ultra-endurance athletes (peak oxygen uptake [VO(2peak)] 68 +/- 1 ml x kg(-1) x min(-1); mean +/- SEM). For 6 days, subjects consumed a random order of a high-fat (69% fat; FAT-adapt) or a high-CHO (70% CHO; HCHO) diet, each followed by 1 day of a high-CHO diet. Treatments were separated by an 18-day wash out. Substrate oxidation was determined during submaximal cycling (20 min at 65% VO(2peak)) prior to and following the 6 day dietary interventions. Fat oxidation at baseline was not different between treatments (17.4 +/- 2.1 vs. 16.1 +/- 1.3 g x 20 min(-1) for FAT-adapt and HCHO, respectively) but increased 34% after 6 days of FAT-adapt (to 23.3 +/- 0.9 g x 20 min(-1), p < .05) and decreased 30% after HCHO (to 11.3 +/- 1.4 g x 20 min(-1), p < .05). Glucose tolerance, determined by the area under the plasma [glucose] versus time curve during an oral glucose tolerance (OGTT) test, was similar at baseline (545 +/- 21 vs. 520 +/- 28 mmol x L(-1) x 90 min(-1)), after 5-d of dietary intervention (563 +/- 26 vs. 520 +/-18 mmol x L(-1) x 90 min(-1)) and after 1 d of high-CHO (491 +/- 28 vs. 489 +/- 22 mmol x L(-1) x 90 min(-1) for FAT- adapt and HCHO, respectively). An index of whole-body insulin sensitivity ( S(I), 10000/divided by fasting [glucose] x fasting [insulin] x mean [glucose] during OGTT x mean [insulin] during OGTT) was similar at baseline (15 +/- 2 vs. 17 +/- 5 arbitrary units), after 5-d of dietary intervention (15 +/- 2 vs. 15 +/- 2) and after 24 h of CHO loading (17 +/- 3 vs. 18 +/- 2 for FAT- adapt and HCHO, respectively). We conclude that despite marked changes in the pattern of substrate oxidation during submaximal exercise, short-term adaptation to a high-fat diet does not alter whole-body glucose tolerance or an index of insulin sensitivity in highly-trained individuals.

Effects of fat adaptation and carbohydrate restoration on prolonged endurance exercise.

We determined the effect of fat adaptation on metabolism and performance during 5 h of cycling in seven competitive athletes who consumed a standard carbohydrate (CHO) diet for 1 day and then either a high-CHO diet (11 g. kg(-1)x day(-1) CHO, 1 g x kg(-1) x day(-1) fat; HCHO) or an isoenergetic high-fat diet (2.6 g x kg(-1) x day(-1) CHO, 4.6 g x kg(-1) x day(-1) fat; fat-adapt) for 6 days. On day 8, subjects consumed a high-CHO diet and rested. On day 9, subjects consumed a preexercise meal and then cycled for 4 h at 65% peak O(2) uptake, followed by a 1-h time trial (TT). Compared with baseline, 6 days of fat-adapt reduced respiratory exchange ratio (RER) with cycling at 65% peak O(2) uptake [0.78 +/- 0.01 (SE) vs. 0.85 +/- 0.02; P < 0.05]. However, RER was restored by 1 day of high-CHO diet, preexercise meal, and CHO ingestion (0.88 +/- 0.01; P < 0.05). RER was higher after HCHO than fat-adapt (0.85 +/- 0.01, 0.89 +/- 0.01, and 0.93 +/- 0.01 for days 2, 8, and 9, respectively; P < 0.05). Fat oxidation during the 4-h ride was greater (171 +/- 32 vs. 119 +/- 38 g; P < 0.05) and CHO oxidation lower (597 +/- 41 vs. 719 +/- 46 g; P < 0.05) after fat-adapt. Power output was 11% higher during the TT after fat-adapt than after HCHO (312 +/- 15 vs. 279 +/- 20 W; P = 0.11). In conclusion, compared with a high-CHO diet, fat oxidation during exercise increased after fat-adapt and remained elevated above baseline even after 1 day of a high-CHO diet and increased CHO availability. However, this study failed to detect a significant benefit of fat adaptation to performance of a 1-h TT undertaken after 4 h of cycling.

High-level production of recombinant Aspergillus niger cinnamoyl esterase (FAEA) in the methylotrophic yeast Pichia pastoris.

The cDNA encoding Aspergillus niger cinnamoyl esterase (FAEA) with its native signal sequence was isolated by reverse transcriptase-polymerase chain reaction, sequenced, and expressed in Pichia pastoris. Secretion yields up to 300 mg l(-1) were obtained in buffered medium. The recombinant FAEA was purified to homogeneity using a one-step purification protocol and found to be identical to the native enzyme with respect to size, pI, immunoreactivity and N-terminal sequence. Specific activity, pH and temperature optimum, and kinetic parameters were also found similar to the native esterase. FAEA is thus the first fungal esterase efficiently produced using a heterologous system.

Effect of fat adaptation and carbohydrate restoration on metabolism and performance during prolonged cycling.

For 5 days, eight well-trained cyclists consumed a random order of a high-carbohydrate (CHO) diet (9.6 g. kg(-1). day(-1) CHO, 0.7 g. kg(-1). day(-1) fat; HCHO) or an isoenergetic high-fat diet (2.4 g. kg(-1). day(-1) CHO, 4 g. kg(-1). day(-1) fat; Fat-adapt) while undertaking supervised training. On day 6, subjects ingested high CHO and rested before performance testing on day 7 [2 h cycling at 70% maximal O(2) consumption (SS) + 7 kJ/kg time trial (TT)]. With Fat-adapt, 5 days of high-fat diet reduced respiratory exchange ratio (RER) during cycling at 70% maximal O(2) consumption; this was partially restored by 1 day of high CHO [0.90 +/- 0.01 vs. 0.82 +/- 0.01 (P < 0.05) vs. 0.87 +/- 0.01 (P < 0.05), for day 1, day 6, and day 7, respectively]. Corresponding RER values on HCHO trial were [0. 91 +/- 0.01 vs. 0.88 +/- 0.01 (P < 0.05) vs. 0.93 +/- 0.01 (P < 0.05)]. During SS, estimated fat oxidation increased [94 +/- 6 vs. 61 +/- 5 g (P < 0.05)], whereas CHO oxidation decreased [271 +/- 16 vs. 342 +/- 14 g (P < 0.05)] for Fat-adapt compared with HCHO. Tracer-derived estimates of plasma glucose uptake revealed no differences between treatments, suggesting muscle glycogen sparing accounted for reduced CHO oxidation. Direct assessment of muscle glycogen utilization showed a similar order of sparing (260 +/- 26 vs. 360 +/- 43 mmol/kg dry wt; P = 0.06). TT performance was 30.73 +/- 1.12 vs. 34.17 +/- 2.48 min for Fat-adapt and HCHO (P = 0.21). These data show significant metabolic adaptations with a brief period of high-fat intake, which persist even after restoration of CHO availability. However, there was no evidence of a clear benefit of fat adaptation to cycling performance.

The Neurospora am gene and NADP-specific glutamate dehydrogenase: mutational sequence changes and functional effects--more mutants and a summary.

A further series of mutant am alleles, encoding potentially active NADP-specific glutamate dehydrogenase (GDH) and capable of complementation in heterocaryons, have been characterized with respect to both GDH properties and DNA sequence changes. Several mutants previously studied, and some of their same-site or second-site revertants, have also been sequenced for the first time. We present a summary of what is known of the properties of all am mutants that have been defined at the sequence level.

Genetic and biochemical characterization of a highly thermostable alpha-L-arabinofuranosidase from Thermobacillus xylanilyticus.

The gene encoding an alpha-L-arabinofuranosidase from Thermobacillus xylanilyticus D3, AbfD3, was isolated. Characterization of the purified recombinant alpha-L-arabinofuranosidase produced in Escherichia coli revealed that it is highly stable with respect to both temperature (up to 90 degrees C) and pH (stable in the pH range 4 to 12). On the basis of amino acid sequence similarities, this 56, 071-Da enzyme could be assigned to family 51 of the glycosyl hydrolase classification system. However, substrate specificity analysis revealed that AbfD3, unlike the majority of F51 members, displays high activity in the presence of polysaccharides.

A single domain thermophilic xylanase can bind insoluble xylan: evidence for surface aromatic clusters.

A clone expressing xylanase activity in Escherichia coli has been selected from a genomic plasmid library of the thermophilic Bacillus strain D3. Subcloning from the 9-kb insert located the xylanase activity to a 2.7-kb HindII/BamHI fragment. The DNA sequence of this clone revealed an ORF of 367 codons encoding a single domain type-F or family 10 enzyme, which was designated as XynA. Purification of the enzyme following over-expression in E. coli produced an enzyme of 42 kDa with a temperature optimum of 75 degrees C which can efficiently bind and hydrolyse insoluble xylan. The pH optimum of the enzyme is 6.5, but it is active over a broad pH range. A homology model of the xylanase has been constructed which reveals a series of surface aromatic residues which form hydrophobic clusters. This unusual structural feature is strikingly similar to the situation observed in the structure determined for the type-G xylanase from the Bacillus D3 strain and may constitute a common evolutionary mechanism imposed on different structural frameworks by which these xylanases may bind potential substrates and exhibit thermostability.

Stress-induced cortisol, mood, and fat distribution in men.

OBJECTIVE: A previous study in our laboratory (Moyer et al., Obes Res. 1994;2:255-62 found that, in response to uncontrollable laboratory stress, women with a high waist-to-hip ratio (WHR) had higher cortisol reactivity, poorer coping skills, and lower anger responses than women with low WHR. We aimed to compare high WHR men's stress responses to these women. RESEARCH METHODS AND PROCEDURES: The current study examined cortisol reactivity and psychological data of 27 healthy high WHR men exposed to the same laboratory challenges as the women from our previous study. Men's data are discussed in relation to that of the high and low WHR women. RESULTS: Men responded to the stress with increases in both cortisol and blood pressure. In comparison with the high and low WHR women, men had significantly higher total cortisol on the stress day. However, when comparing a sub-sample of men and women matched in WHR's, differences in cortisol secretion were greatly diminished and no longer significant. In addition, men had higher desire for control than both high and low WHR women, and lower mood reactivity than low WHR women. Despite the lower mood reactivity of high WHR groups, the high mood reactors among the high WHR women, and to a lesser extent, men, tended to have higher cortisol reactivity. DISCUSSION: These results suggest that the psychological differences and greater exposure to cortisol observed among the high WHR men and women may have played a role in contributing to their greater abdominal fat depots.

Diversity and medical education.

Perhaps one measure of wisdom is our willingness to listen to the tales of that man of a different color on our left and that woman of a different color on our right as we walk together toward life's inevitable crises.