Mechanisms of resistance to daptomycin in Enterococcus faecium

In this study, we investigated the clonal emergence of daptomycin-resistant Enterococcus faecium strains isolated from a patient with leukocyte adhesion deficiency syndrome. The resistance mechanism in these strains is independent of either equivalent point mutations previously described for Staphylococcus aureus or daptomycin inactivation mechanisms identified in soil bacteria.     

Effect of sodium overload on renal function of offspring from diabetic mothers

The aim if this study was to evaluate the effect of sodium overload on blood pressure and renal function in the offspring of diabetic rat mothers. Diabetes was induced with a single dose of streptozotocin before mating. Experimental groups were control (C), offspring from diabetic mother (D), control with sodium chloride (NaCl) overload (CS), and offspring from diabetic mother submitted to NaCl overload (DS). After weaning, all groups received food ad libitum; groups C and D had water ad libitum, and CS and DS received NaCl 0.15 M as drinking water. Renal morphology and function were evaluated in 3-month-old rats. Glomerular area, macrophage infiltration, interlobular artery wall thickness, and renal vascular resistance were significantly increased in CS, D, and DS compared with C. Renal plasma flow (RPF) and glomerular filtration rate (GFR) were decreased in CS and D compared with C. In DS, GFR and fractional filtration were increased, suggesting a state of hyperfiltration. Hypertension was observed in groups D, CS, and DS from 2 months on and was more severe in DS. Our data suggest that diabetes during intrauterine development and salt overload beginning at an early age can cause hypertension and renal injury. When these conditions were associated, morphological and functional changes were much more intense, suggesting acceleration in the process of kidney injury.     

Lipid imaging of human skeletal muscle using TOF-SIMS with bismuth cluster ion as a primary ion source

Intramyocellular lipids are of importance in lipid-related diseases. The techniques in this field are limited because of a lack of adequate tools for localization of various lipids. The most usual methods for the localization of lipid distribution in the skeletal muscle are histochemistry and fluorescence probes. Different chromatography methods and mass spectrometry techniques have also been used for lipid identification. Our aim was to localize the spatial distribution of lipids in their native forms by using static time-of-flight secondary-ion mass spectrometry (TOF-SIMS). Human percutaneous skeletal muscle biopsies were obtained from the middle part of the lateral vastus muscle in the right leg of healthy adolescents with a body mass index >30. Samples were prepared by high-pressure freezing, freeze-fracturing and freeze-drying, and analysed by imaging TOF-SIMS equipped with a Bi3+ cluster ion gun. In the positive spectra, we identified phosphocholine, cholesterol, diacylglycerol, phospholipids and triacylglycerol. Phosphocholine was localized to the edge of the fibre, representing the sarcoplasma or endomysium. Weak cholesterol signals were observed in the intracellular areas. High diacylglycerol and low triacylglycerol signal intensities were seen in intracellular spaces of the transversal area of the muscle fibre. In the negative spectra, we identified fatty acids. We observed co-localization of fatty acids and diacylglycerol, which may indicate lipid-storing parts of the skeletal muscle. Thus, TOF-SIMS imaging can be used to depict the heterogeneous localization of lipids in human skeletal muscle.     

MEFV and NLRP3 Inflammasome Expression Is Attributed to Immature Macrophages and Correlates with Serum Inflammatory Proteins in Crohn´s Disease Patients

Inflammation - Inflammasomes are intracellular protein complexes whose activation results in proinflammatory cytokines. Inflammasomes are implicated in Crohn´s disease (CD) pathogenesis, yet...     

Pennation angle dependency in skeletal muscle tissue doppler strain in dynamic contractions

Tissue velocity imaging (TVI) is a Doppler based ultrasound technique that can be used to study regional deformation in skeletal muscle tissue. The aim of this study was to develop a biomechanical model to describe the TVI strain’s dependency on the pennation angle. We demonstrate its impact as the subsequent strain measurement error using dynamic elbow contractions from the medial and the lateral part of biceps brachii at two different loadings; 5% and 25% of maximum voluntary contraction (MVC). The estimated pennation angles were on average about 4° in extended position and increased to a maximal of 13° in flexed elbow position. The corresponding relative angular error spread from around 7% up to around 40%. To accurately apply TVI on skeletal muscles, the error due to angle changes should be compensated for. As a suggestion, this could be done according to the presented model.     

A gap between the philosophy and the practice of palliative healthcare: sociological perspectives on the practice of nurses in specialised palliative homecare

Medicine, Health Care and Philosophy - Palliative care philosophy is based on a holistic approach to patients, but research shows that possibilities for living up to this philosophy seem limited by...     

Stabilization of neurotoxic Alzheimer amyloid-β oligomers by protein engineering

Soluble oligomeric aggregates of the amyloid-β peptide (Aβ) have been implicated in the pathogenesis of Alzheimer’s disease (AD). Although the conformation adopted by Aβ within these aggregates is not known, a β-hairpin conformation is known to be accessible to monomeric Aβ. Here we show that this β-hairpin is a building block of toxic Aβ oligomers by engineering a double-cysteine mutant (called Aβcc) in which the β-hairpin is stabilized by an intramolecular disulfide bond. Aβ₄₀cc and Aβ₄₂cc both spontaneously form stable oligomeric species with distinct molecular weights and secondary-structure content, but both are unable to convert into amyloid fibrils. Biochemical and biophysical experiments and assays with conformation-specific antibodies used to detect Aβ aggregates in vivo indicate that the wild-type oligomer structure is preserved and stabilized in Aβcc oligomers. Stable oligomers are expected to become highly toxic and, accordingly, we find that β-sheet-containing Aβ₄₂cc oligomers or protofibrillar species formed by these oligomers are 50 times more potent inducers of neuronal apoptosis than amyloid fibrils or samples of monomeric wild-type Aβ₄₂, in which toxic aggregates are only transiently formed. The possibility of obtaining completely stable and physiologically relevant neurotoxic Aβ oligomer preparations will facilitate studies of their structure and role in the pathogenesis of AD. For example, here we show how kinetic partitioning into different aggregation pathways can explain why Aβ₄₂ is more toxic than the shorter Aβ₄₀, and why certain inherited mutations are linked to protofibril formation and early-onset AD.     

Insulin receptor substrates-1 and -2 are both depleted but via different mechanisms after down-regulation of glucose transport in rat adipocytes

Alterations in muscle and adipose tissue insulin receptor substrate (IRS)-1 and IRS-2 are associated with, and commonly believed to contribute to, development of insulin resistance. In this study, we investigated the mechanisms behind previously observed reductions in IRS levels due to high concentrations of glucose and insulin and their significance in the impairment of glucose uptake capacity in primary rat adipocytes. Semiquantitative RT-PCR analysis showed that insulin (10(4) microU/ml) alone or in combination with glucose (15 mm) markedly suppressed IRS-2 gene expression, whereas IRS-1 mRNA was unaffected by the culture conditions. The negative effect of a high glucose/high insulin setting on IRS-1 protein level was still exerted when protein synthesis was inhibited with cycloheximide. Impairment of glucose uptake capacity after treatment with high glucose and insulin was most pronounced after 3 h, whereas IRS-1 and IRS-2 protein levels were unaffected up to 6 h but were reduced after 16 h. Moreover, impaired glucose uptake capacity could only partially be reversed by subsequent incubation at physiological conditions. These novel results suggest that: 1) in a high glucose/high insulin setting depletion of IRS-1 and IRS-2 protein, respectively, occurs via different mechanisms, and IRS-2 gene expression is suppressed, whereas IRS-1 depletion is due to posttranslational mechanisms; 2) IRS-1 and IRS-2 protein depletion is a secondary event in the development of insulin resistance in this model of hyperglycemia/hyperinsulinemia; and 3) depletion of cellular IRS in adipose tissue may be a consequence rather than a cause of insulin resistance and hyperinsulinemia in type 2 diabetes.     

Aminotransferase activity in morbid and uncomplicated obesity: predictive role of fasting insulin

Background and aims.An elevation in liver enzymes and, most notably, high serum alanine aminotransferase (ALT) activity, has been correlated with metabolic syndrome and obesity. However, whether obesity per se or obesity-related co-morbidities affect aminotransferase activity is still unclear. In this study we sought to evaluate serum aminotransferase activity in morbid and uncomplicated obese subjectsMethods.In this cross-sectional study, serum aminotransferase activity, anthropometric and metabolic parameters were assessed in 290 morbid and 105 uncomplicated consecutive obese subjects matched for body mass index (BMI) (40.1 ± 6.8 vs. 39.9 ± 8.3 kg/m², respectively), age (35.9 ± 10 vs. 34.8 ± 9.6 years, respectively), sex distribution and duration of obesity.Results.Uncomplicated obese subjects showed significantly lower serum ALT activity (17.58 ± 6.3 (range 10–39) vs. 23.43 ± 16 (range 12–89) U/l, (p < 0.001)), and lower aspartate aminotransferase (AST), AST/ALT ratios and gamma-glutamyltranspeptidase (γGT) (p < 0.01 for all) than morbid obese subjects. Only 11% women and 19% men in the uncomplicated obese group showed high ALT levels, while ALT activity was high in 48% women and 51% men in the morbid obese group. Fasting insulin was the best correlate of ALT activity (R² = 0.21, p = 0.003).Conclusions.Our findings show that elevated ALT and AST activity are associated with increased fasting insulin and not with obesity per se, suggesting that the presence of insulin resistance, rather than BMI alone, plays a role in mediating the increased aminotransferase activity.     

In vitro reversal of hyperglycemia normalizes insulin action in fat cells from type 2 diabetes patients: is cellular insulin resistance caused by glucotoxicity in vivo?

Chronic hyperglycemia promotes the development of insulin resistance. The aim of this study was to investigate whether cellular insulin resistance is secondary to the diabetic state in human type 2 diabetes. Subcutaneous fat biopsies were taken from 3 age-, sex-, and body mass index (BMI)-matched groups with 10 subjects in each group: type 2 diabetes patients with either good (hemoglobin A(1c) [HbA(1c)] < 7%, G) or poor (HbA(1c) > 7.5%, P) metabolic control and healthy control subjects (C). Insulin action in vitro was studied by measurements of glucose uptake both directly after cell isolation and following a 24-hour incubation at a physiological glucose level (6 mmol/L). The relationship with insulin action in vivo was addressed by employing the euglycemic clamp technique. Freshly isolated fat cells from type 2 diabetes patients with poor metabolic control had approximately 55% lower maximal insulin response (1,000 microU/mL) on glucose uptake (P <.05) compared to C. Cells from P were more insulin-resistant (P <.05) than cells from G at a low (5 microU/mL) but not at a high (1,000 microU/mL) insulin concentration, suggesting insulin insensitivity. However, following 24 hours of incubation at physiological glucose levels, insulin resistance was completely reversed in the diabetes cells and no differences in insulin-stimulated glucose uptake were found among the 3 groups. Insulin sensitivity in vivo assessed with hyperinsulinemic, euglycemic clamp (M-value) was significantly associated with insulin action on glucose uptake in fresh adipocytes in vitro (r = 0.50, P <.01). Fasting blood glucose at the time of biopsy and HbA(1c), but not serum insulin, were negatively correlated to insulin's effect to stimulate glucose uptake in vitro (r = -0.36, P =.064 and r = - 0.41, P <.05, respectively) in all groups taken together. In the in vivo situation, fasting blood glucose, HbA(1c), and serum insulin were all negatively correlated to insulin sensitivity (M-value; r = -0.62, P<.001, r= -0.61, P<.001, and r = -0.56, p <.01, respectively). Cell size, waist-to-hip ration (WHR), and BMI correlated negatively with insulin's effect to stimulate glucose uptake both in vitro (r = -0.55, P <.01, r = -0.54, P <.01, and r = -0.43, P <.05, respectively) and in vivo (r = -0.43, P <.05, r = -0.50, P <.01, and r = -0.36, P <.05, respectively). Multiple regression analyses revealed that adipocyte cell size and WHR independently predicted insulin resistance in vitro. Furthermore, insulin sensitivity in vivo could be predicted by fasting blood glucose and serum insulin levels. We conclude that insulin resistance in fat cells from type 2 diabetes patients is fully reversible following incubation at physiological glucose concentrations. Thus, cellular insulin resistance may be mainly secondary to the hyperglycemic state in vivo.