Technical education and training: with special reference to developing countries

The typesetting book content by the jointed authors, D. D. Waters and J. W. Gailer

Methylated Trivalent Arsenic-Glutathione Complexes are More Stable than their Arsenite Analog

The trivalent arsenic glutathione complexes arsenic triglutathione, methylarsonous diglutathione, and dimethylarsinous glutathione are key intermediates in the mammalian metabolism of arsenite and possibly represent the arsenic species that are transported from the liver to the kidney for urinary excretion. Despite this, the comparative stability of the arsenic-sulfur bonds in these complexes has not been investigated under physiological conditions resembling hepatocyte cytosol. Using size-exclusion chromatography and a glutathione-containing phosphate buffered saline mobile phase (5 or 10 mM glutathione, pH 7.4) in conjunction with an arsenic-specific detector, we chromatographed arsenite, monomethylarsonous acid, and dimethylarsinous acid. The on-column formation of the corresponding arsenic-glutathione complexes between 4 and 37°C revealed that methylated arsenic-glutathione complexes are more stable than arsenic triglutathione. The relevance of these results with regard to the metabolic fate of arsenite in mammals is discussed

Evaluation and comparison of trace metals accumulation in different tissues of potential bioindicator organisms: Macrobenthic filter feeders Styela plicata, sabella spallanzanii and Mytilus galloprovincialis

Trace metal concentrations were measured in different tissues of Sabella spallanzanii, Styela plicata and Mytilus galloprovincialis collected in Termini Imerese harbor, located in Sicily (Italy), in order to evaluate the potential use of these species as bioindicators. The higher bioaccumulation factors (BAFs) were calculated in tube of Sabella spallanzanii, except for As which shows the higher BAF in branchial crown of the same specie. Regarding the other species analyzed, higher BAFs were found in the digestive gland of Mytilus galloprovincialis. An exception is represented by Pb that is significantly more concentrated in branchial basket and tunic of Styela plicata. The BAFs here calculated, show that all the species analyzed are able to accumulate a certain amount of metals as a consequence of filter feeding mechanisms, and thus assess the suitability of the species Styela plicata, Sabella spallanzanii and Mytilus galloprovincialis as indicators of water quality. Particularly, the tube of Sabella spallanzanii is an important compartment in metal retention and the more suitable for the evaluation of the contamination caused by trace elements. This article is protected by copyright. All rights reserved

Combining two grading systems:the clinical validity and inter-observer variability of the 1973 and 2004 WHO bladder cancer classification systems assessed in a UK cohort with 15 years of prospective follow-up

PURPOSE: Paucity of reliable long-term data on the prognostic implications of the 2004 WHO bladder cancer classification system necessitates utilisation of both this and the 1973 grading systems. This study evaluated, in noninvasive (pTa) bladder tumours, the prognostic value of the 2004 system independently and in combination with the 1973 system while establishing concordance between tertiary centre uropathologists.METHODS: We used a cohort of non-muscle invasive bladder cancer (NMIBC) patients diagnosed between 1991 and 93 where tumour features were gathered prospectively with detailed cystoscopic follow-up data recorded over 15 years. Initial grading was by one senior expert uropathologist (UP1) using the 1973 WHO classification alone. Subsequently, two other expert uropathologists (UP2 and UP3), blinded to the previous grading, re-evaluated the pathology slides and graded the tumours using both the 1973 and 2004 systems. Association between grade and recurrence/progression was analysed and the Cohen Kappa test assessed concordance between pathologists.RESULTS: Of 370 new NMIBC, 229 were staged noninvasive (pTa). Recurrence rates were 46.2% and 50.0% for LGPUC (low-grade papillary urothelial carcinoma) and HGPUC (high-grade papillary urothelial carcinoma), respectively, while progression was seen in 3.9% and 10.0% of LGPUC and HGPUC, respectively. Concordance between uropathologists UP2 and UP3 for the 2004 and 1973 systems was good (Kappa = 0.69) and fair (Kappa = 0.25), respectively.CONCLUSIONS: With good inter-observer concordance, the 2004 WHO classification system of noninvasive bladder tumours appears to accurately predict recurrence and progression risks. The combination of both grading systems to low-grade tumours allows further refinement of the natural history.</p

Prospective evaluation of a primary care referral pathway for patients with non-alcoholic fatty liver disease.

BACKGROUND & AIMS: We aimed to develop and evaluate a pathway for management of patients with non-alcoholic fatty liver disease (NAFLD) using blood tests to stratify patients in primary care to improve detection of cases of advanced fibrosis and cirrhosis, and avoid unnecessary referrals to secondary care. METHODS: This was a prospective longitudinal cohort study with before-and-after analysis and comparison to unexposed controls. We used a two-step algorithm combining the use of FIB-4 followed by the ELF test if required RESULTS: In total, 3,012 patients were analysed. Use of the pathway detected 5 times more cases of advanced fibrosis (Kleiner F3) and cirrhosis (OR=5.18; 95%CI=2.97 to 9.04; p<0.0001). Unnecessary referrals from primary care to secondary care fell by 81% (OR=0.193; 95%CI 0.111 to 0.337; p<0.0001). Three times more cases of cirrhosis were diagnosed (OR=3.14; 95%CI=1.57 to 24; p=0.00011). Although it was used for only 48% of referrals, significant benefits were observed across all referrals from the practices exposed to the pathway. Unnecessary referrals fell by 77% (OR=0.23; 95% CI=0.658 to 0.082; p=0.006) with a 4-fold improvement in detection of cases of advanced fibrosis and cirrhosis (OR=4.32; 95% CI=1.52 to 12.25; p=0.006). Compared to referrals made before introduction of the pathway, unnecessary referrals fell from 79/83 referrals (95.2%) to 107/152 (70.4%) representing an 88% reduction in unnecessary referrals when the pathway was followed (OR=0.12; 95%CI=0.042 to 0.349; p<0.0001). CONCLUSIONS: The use of non-invasive blood tests for liver fibrosis to stratify patients with NAFLD improves the detection of cases of advanced fibrosis and cirrhosis and reduces unnecessary referrals to secondary care of patients with lesser degrees of liver fibrosis. This strategy improves resource use and benefits patients. LAY SUMMARY: Non-alcoholic fatty liver disease effects up to 30% of the population but only a minority of cases develop liver disease. Our study has shown that established blood tests can be used in primary care to stratify patients with fatty liver disease to reduce unnecessary referrals by 80% and improve the detection of cases of advanced fibrosis 5 fold and cirrhosis 3 fold

Conditional and reversible activation of class A and B G protein-coupled receptors using tethered pharmacology

Understanding the activation and internalization of G protein-coupled receptors (GPCRs) using conditional approaches is paramount to developing new therapeutic strategies. Here, we describe the design, synthesis, and testing of ExONatide, a benzylguanine linked peptide agonist of the glucagon-like peptide-1 receptor (GLP-1R), a class B GPCR required for maintenance of glucose levels in humans. ExONatide covalently binds to SNAP-tagged GLP-1R-expressing cells, leading to prolonged cAMP generation, Ca2+ rises and intracellular retention of the receptor. These effects were readily switched OFF following cleavage of the introduced disulfide bridge using a cell-permeable reducing agent. A similar approach could be extended to a class A GPCR using GhrelON, a benzylguanine-linked peptide agonist of the growth hormone secretagogue receptor 1a (GHS-R1a), which is involved in food intake and growth. Thus, ExONatide and GhrelON allow SNAP-tag-directed activation of class A and B GPCRs involved in gut hormone signaling in a reversible manner. This tactic, termed reductively cleavable agONist (RECON), may be useful for understanding GLP-1R and GHS-R1a function both in vitro and in vivo, with applicability across GPCRs

Insights into the chemical biology of selenium

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