Age related profiles of free amino acids in human skeletal muscle

Sarcopenia describes the involuntary decline in muscle mass with aging, coupled with fatigue, and loss of force and function. We investigated 113 human muscle biopsy specimens obtained from patients with neuromuscular diseases and controls. We measured 21 amino acids in these muscle biopsies. Age emerged as a significant negative predictor of cytosolic concentration ratio of glutamine to total branched chain amino acids and of glutamine to total aromatic amino acids using stepwise multiple linear regression analysis. This pattern of alteration corresponds well to documented alterations in skeletal muscle of critically ill patients and after immobilization. Additionally, in myositis, citrulline was significantly elevated, while glutamate, lysine and taurine were significantly reduced. Furthermore, in sporadic amyotrophic lateral sclerosis (sALS) the total aromatic amino acids, arginine, glutamate, threonine, and tyrosine were significantly elevated. This study provides evidence, that alteration of glutamine is correlated to aging and might reflect increased proteolysis in aged and diseased human skeletal muscle.     

Compilation and use of genetic toxicity historical control data

The optimal use of historical control data for the interpretation of genotoxicity results was discussed at the 2009 International Workshop on Genotoxicity Testing (IWGT) in Basel, Switzerland. The historical control working group focused mainly on negative control data although positive control data were also considered to be important. Historical control data are typically used for comparison with the concurrent control data as part of the assay acceptance criteria. Historical control data are also important for providing evidence of the technical competence and familiarization of the assay at any given laboratory. Moreover, historical control data are increasingly being used to aid in the interpretation of genetic toxicity assay results. The objective of the working group was to provide generic advice for historical control data that could be applied to all assays rather than to give assay-specific recommendations. In brief, the recommendations include:     

Momordica charantia extract, a herbal remedy for type 2 diabetes, contains a specific 11β-hydroxysteroid dehydrogenase type 1 inhibitor

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes the intracellular regeneration of active cortisol from inert cortisone in key metabolic tissues, thus regulating ligand access to glucocorticoid receptors. There is strong evidence that increased adipose 11β-HSD1 activity may be an important aetiological factor in the current obesity and diabetes type 2 epidemics. Hence, inhibition of 11β-HSD1 has emerged as a promising anti-diabetic strategy, a concept that is largely supported by numerous studies in rodent models as well as limited clinical data with prototype inhibitors. Momordica charantia (also known as bitter melon, bitter gourd or karela) is traditionally used for treatment of diabetes in Asia, South America, the Caribbean, and East Africa. In the present study, we show that M. charantia extract capsules contain at least one ingredient with selective 11β-HSD1 inhibitory activity. The finding constitutes an interesting additional explanation for the well-documented anti-diabetic and hypoglycaemic effects of M. charantia.     

Decreased plasma and cerebrospinal fluid ascorbate levels in patients with septic encephalopathy

Septic encephalopathies rapidly affect brain function without the involvement of a specific area causing a broad range of reversible neurologic symptoms. Capillary leakage including dysfunction of the blood-brain barrier has been proposed as a potential pathogenic mechanism in this entity. We tested the hypothesis that oxidative stress measured in plasma and cerebrospinal fluid (CSF) of patients suffering from septic encephalopathy could be linked to the neurologic symptoms of the disease. The neurologic symptoms of eleven patients with septic encephalopathy were described semiquantitatively through a score system. The ascorbate levels were significantly lower in both plasma and CSF from patients with septic encephalopathy than controls, and in CSF but not plasma this decrease correlated with the severity of neurologic symptoms. No significant changes were found for alpha-tocopherol. Our findings suggest that the short-term oxidative stress may be an important factor in the development of septic encephalopathy, possibly through dysregulation of the blood-brain barrier.     

On the Social Behaviour of Cells

Polystyrene Petri dishes are in use in hundreds of thousands of laboratories world wide. Cell culture experiments performed in them provide fundamental information in a wide range of applications, including but not limited to testing novel biomaterials and pharmaceuticals, and stem cell research. These experiments cost billions of dollars per year. In this study we report on a potential deficiency of polystyrene Petri dishes, possibly caused by an increase in interracial pH under relevant culture condi-tions and affecting cell performance. We conclude that cell performance on Petri dishes could be improved by improving the Petri dishes. As a spin-off of our study we postulate the concept that cancer cells and stem cells are social. It is impossible to validate this concept on the basis of the model established in this paper. However. the coherence of our insights may encourage further study and lead to the development of a qualitative improvement of cell culture devices, including Petri dishes and culture flasks, to the identification of potential strategies for chemotherapy and chemoprevention that could suppress progression of metastasis, and to the establishment of improved settings for tissue engineering and stem cell research. An immediate recom-mendation of our study is to use chemically and biologically inert substrates for important cell culture experiments, for example, nanocrystalline diamond.     

Formation of sperm bundles in Pterostichus nigrita (Coleoptera: Carabidae)

The formation and structure of sperm bundles (spermiozeugmata), and the structure of the vas deferens where bundles are formed, in Pterostichus nigrita is described by light and electron microscopy. The spermiozeugmata are of the sheet-like type consisting of a central rod (about 3?mm long) of electron-dense material (the spermatostyle), to which two bundles of spermatozoa (about 95 per bundle) are attached. The spermatostyle has a spoon-shaped head, and the rod material is differentiated into an electron-dense core and a more electron-lucent cortex. Spermatozoa (about 340?µm long) are attached to the anterior portion of the rod only. Spermiozeugma formation occurs in the upper vas deferens (before the seminal vesicle region) with the secretion of rod material by epithelial cells, which are characterized by well developed rough endoplasmic reticulum with distended cisternae, abundant mitochondria and Golgi bodies. Some cells contain numerous myeloid structures thought to be precursors of rod material, and coated vesicles. During spermiozeugma development, the heads of spermatozoa become embedded in the developing rod material, the anterior of which sits in one of the many diverticula of the mid-region of the vas deferens. Elongation of the rod proceeds by addition of material posteriorly.     

Renal Function Interferes with Copeptin in Prediction of Major Adverse Cardiac Events in Patients Undergoing Vascular Surgery

Objective

Precise perioperative risk stratification is important in vascular surgery patients who are at high risk for major adverse cardiovascular events (MACE) peri- and postoperatively. In clinical practice, the patient’s perioperative risk is predicted by various indicators, e.g. revised cardiac index (RCRI) or modifications thereof. Patients suffering from chronic kidney disease (CKD) are stratified into a higher risk category. We hypothesized that Copeptin as a novel biomarker for hemodynamic stress could help to improve the prediction of perioperative cardiovascular events in patients undergoing vascular surgery including patients with chronic kidney disease.

Methods

477 consecutive patients undergoing abdominal aortic, peripheral arterial or carotid surgery from June 2007 to October 2012 were prospectively enrolled. Primary endpoint was 30-day postoperative major adverse cardiovascular events (MACE).

Results

41 patients reached the primary endpoint, including 63.4% aortic, 26.8% carotid, and 9.8% peripheral surgeries. Linear regression analysis showed that RCRI (P< .001), pre- (P< .001), postoperative Copeptin (P< .001) and Copeptin level change (P= .001) were associated with perioperative MACE, but CKD remained independently associated with MACE and Copeptin levels. Multivariate regression showed that increased Copeptin levels added risk predictive information to the RCRI (P= .003). Especially in the intermediate RCRI categories was Copeptin significantly associated with the occurrence of MACE. (P< .05 Kruskal Wallis test). Subdivision of the study cohort into CKD stages revealed that preoperative Copeptin was significantly associated with CKD stages (P< .0001) and preoperative Copeptin measurements could not predict MACE in patients with more severe CKD stages.

Conclusion

Preoperative Copeptin loses its risk predictive potential for perioperative MACE in patients with chronic kidney disease undergoing vascular surgery.     

Green Tea and One of Its Constituents,Epigallocatechine-3-gallate,Are Potent Inhibitors of Human 11β-hydroxysteroid Dehydrogenase Type 1

The microsomal enzyme 11β-hydroxysteroid deydrogenase type 1 (11β-HSD1) catalyzes the interconversion of glucocorticoid receptor-inert cortisone to receptor- active cortisol, thereby acting as an intracellular switch for regulating the access of glucocorticoid hormones to the glucocorticoid receptor. There is strong evidence for an important aetiological role of 11β-HSD1 in various metabolic disorders including insulin resistance, diabetes type 2, hypertension, dyslipidemia and obesity. Hence, modulation of 11β-HSD1 activity with selective inhibitors is being pursued as a new therapeutic approach for the treatment of the metabolic syndrome. Since tea has been associated with health benefits for thousands of years, we sought to elucidate the active principle in tea with regard to diabetes type 2 prevention. Several teas and tea specific polyphenolic compounds were tested for their possible inhibition of cortisone reduction with human liver microsomes and purified human 11β-HSD1. Indeed we found that tea extracts inhibited 11β-HSD1 mediated cortisone reduction, where green tea exhibited the highest inhibitory potency with an IC50 value of 3.749 mg dried tea leaves per ml. Consequently, major polyphenolic compounds from green tea, in particular catechins were tested with the same systems. (−)-Epigallocatechin gallate (EGCG) revealed the highest inhibition of 11β-HSD1 activity (reduction: IC50 = 57.99 µM; oxidation: IC50 = 131.2 µM). Detailed kinetic studies indicate a direct competition mode of EGCG, with substrate and/or cofactor binding. Inhibition constants of EGCG on cortisone reduction were Ki = 22.68 µM for microsomes and Ki = 18.74 µM for purified 11β-HSD1. In silicio docking studies support the view that EGCG binds directly to the active site of 11β-HSD1 by forming a hydrogen bond with Lys187 of the catalytic triade. Our study is the first to provide evidence that the health benefits of green tea and its polyphenolic compounds may be attributed to an inhibition of the cortisol producing enzyme 11β-HSD1.