A Short Route to the Synthesis of Digoxose Trisaccharide Glycal Donor via Mislow-Evans Rearrangement.

The Mislow-Evans rearrangement was used as a key reaction to construct digitoxose-derived glycals. The same rearrangement was iteratively performed on di- and trisaccharides to form the digoxose glycal donor component present in the cardenolides digitoxin, digoxin, and gitoxin. The scalability of the trisaccharide synthesis was shown by performing the reactions on a multigram scale. Glycosylation reactions were also performed between the synthesized digoxin glycal donor and aglycons digoxigenin and gitoxigenin to synthesize novel cardenolide derivatives.

A Ring Expansion─Stereoselective Cycloaddition of Carbohydrate-Derived Donor-Acceptor Cyclopropanes: Synthesis of Bridged Oxepanone-Indole Hybrids.

An efficient method for the construction of sugar-derived chiral oxepanone-indole molecular hybrids is investigated. The reaction condition is optimized by monitoring the progress at various temperatures, with various solvents, and with different Lewis acid catalysts. Under optimized conditions, high stereoselectivity and efficiency are achieved in most of the formed cycloadducts. The accessibility of the strategy is evaluated by utilizing an array of carbohydrate-derived donor-acceptor cyclopropanes and variably substituted indole substrates. Additionally, quick access to the bridged indole-oxepanone framework is described by utilizing a diastereoselective (3+2) cycloaddition of aryl-substituted donor-acceptor cyclopropanes incorporated in a pyran ring.

Synthesis of Hexenuloses and a Library of Disaccharides Possessing 3-oxo-glycal Unit.

An expeditious method for the synthesis of monosaccharides and disaccharides possessing 3-oxo-glycal units is revealed. Several monosaccharides and disaccharide-derived glycals are converted to the corresponding hexenuloses in three steps involving halo-alkoxylation, dehydrohalogenation, and ketalyzation reactions. A number of 3-oxo-glycals are synthesized to show the methodology's importance and generality. Further, the protocol is successfully applied to synthesize a rare-sugar disaccharide donor unit present as part of the trisaccharide moiety in the reported natural product, versipelostatin.

Biosorption of nickel and copper ions from single metal aqueous solutions by fungi.

Batch biosorption studies were carried out for the removal of nickel and copper using biosorbents, from single metal aqueous solutions. Treated and untreated effluent, soil and sludge samples were collected from selected points of chrome plating unit located at Visakhapatnam. The collected samples were analyzed for physico-chemical quality. The effects of some of the major parameters of biosorption, viz. contact time, dose of biosorbent, pH and initial metal concentration were studied and optimized. The optimum contact time, biosorbent dosage and pH were found to be 1 hr, 5 g/L and 10 respectively. The percentage removal of nickel and copper for an initial concentration of 20 ppm, for a dosage of 5 g/ L of dry fungal biomass at pH 10 and for a contact time of 1 hr was found to be 75.5% and 55.5% respectively, whereas, for an initial concentration of 100 ppm under the same optimum conditions, it was found to be 71% and 50% indicating that even at high concentration of metal ions the efficiency of biosorption is high. The dry fungal biomass has more favorable sites for nickel than copper ions.

'Hospital hyperglycaemia'; perception or reality?

Patients' perceptions that clinic fasting blood glucose measurements in Type 2 diabetes are artefactually high were investigated. Eighteen men and 14 women in the Salford cohort of the United Kingdom Prospective Diabetes Study (UKPDS) with a median age of 51 (range 37-69) years measured their fasting blood glucose concentration at home with visually read sticks or meters; they then collected capillary blood into fluoride tubes both at home and in clinic after a median lapse of 77 (range 25-173) min. The clinic samples were measured immediately and after a time lapse equivalent to the time taken to reach clinic to control for continued glycolysis in the home sample. Mean fasting blood glucose was 5.9 +/- 1.9 mmol 1(-1) by the patients' own measurement and 6.0 +/- 1.8 mmol 1(-1) on the home collected sample compared with 6.2 +/- 2.0 mmol 1(-1) and 6.1 +/- 2.0 mmol 1(-1) on the hospital immediate and time-lapsed measurements, respectively (p > 0.05 for all comparisons between home and hospital measurements); although there were no systematic differences, occasional measurements differed more than 2 mmol 1(-1). These data support the use of the fasting blood glucose level as a stable, patient-independent measure of glycaemic control in Type 2 diabetes.

Aluminium ring pulls: an invisible foreign body.

The aluminium ring pulls associated with the latest designs of drinks cans can be relatively easily detached from their mounting on the top of the can and subsequently aspirated. Their small size predisposes them to lodge as foreign bodies (FBs) in the throat. The similarity of atomic number between soft tissue (7.5) and aluminium (13) makes detection of these FBs difficult on soft tissue radiography. If aspiration is suspected direct visualization and removal may be indicated even if radiography is negative.

Auditory problems in elderly patients with stroke.

Twenty-five CAT-scan-confirmed stroke patients and 25 matched controls were studied. All the stroke patients were stable 2-3 months after unilateral hemispheric stroke. Those with ear disease, other central neurological disorder, severe dysphasia and acute or chronic confusion were excluded. There were no significant differences between the groups for average pure tone hearing threshold (APTT) or ability to discriminate pre-recorded speech presented to one ear at 35 decibels (dB) above APTT. The stroke subjects had significantly impaired performance on dichotic competing sentence testing (DCST). Seventeen stroke patients but only one control subject failed DCST. Failure rate was similar for left and right stroke and for temporal and non-temporal lobe involvement. Two-thirds of patients failing DCST did so in the ear opposite the side of the cortical lesion. We conclude that (i) DCST is useful in detecting central auditory dysfunction in stroke patients; and (ii) stroke can affect central auditory perception in older patients.

Gallstone cirrhosis: are we only seeing the tip of the iceberg?

Gallstones are common and their incidence increases with age. Fifty per cent of these stones are in the common bile duct (CBD) in the elderly. Most of them are silent but with time there is an increasing chance of developing symptoms which are more likely to be serious in the elderly. Failure to relieve mechanical obstruction of bile flow may lead to secondary biliary cirrhosis. It has been estimated that on average secondary biliary cirrhosis develops some seven years after the onset of obstruction from a stricture, four and half years after gallstone obstruction and 10 months after the onset of malignant stricture. The characteristic features are the pathological findings of portal-portal linkages, with a pattern of monolobular cirrhosis and the preservation of normal vascular relationships. Secondary biliary cirrhosis may lead to hepatic insufficiency and portal hypertension with the resultant complications, such as bleeding oesophageal varices, hypersplenism with pancytopenia, ascites and encephalopathy. We describe a patient in whom the diagnosis was not suspected until laparotomy and confirmed only at autopsy.

Device for quantifying tactile neglect in stroke patients.

Perceptual problems such as tactile neglect are important features of stroke and strong predictors of a poor outcome. Although new methods of treatment have been described, documentation of the effects of such treatment is inadequate, mainly because satisfactory methods of quantifying tactile neglect are unavailable. We describe a device for quantifying neglect based upon the principle of the Bender test which uses double or simultaneous bilateral stimulation to determine neglect. The device, which is computer driven to ensure uniformity of test protocols, determines the cutaneous perceptual threshold to controlled-current electrical stimulation using surface electrodes. The effect of rival contralateral stimulation on the perceptual thresholds on the affected side of the patient's body is a quantitative measure of tactile neglect. The device was evaluated in normal young and neurologically normal elderly subjects and in stroke patients with clinical evidence of tactile neglect. It was shown to distinguish reliably between normal subjects and those who had tactile neglect. The device will be suitable for use in trials of treatments for tactile neglect and in tracking the natural history of this symptom.

Age-related changes in cerebrospinal fluid protein concentrations.

The blood-brain barrier (BBB) has a key role in CSF homeostasis and preservation of normal neuronal function. There has been little investigation of changes in barrier function in elderly subjects without evidence of neurological disease. The ageing brain demonstrates increased vulnerability to a variety of insults, which may reflect a deterioration in barrier performance. Direct measurement of BBB function is difficult but the CSF/serum quotients of individual proteins is the most widely used parameter. The present study sought age related changes in the CSF/serum quotients of prealbumin, albumin, immunoglobulin G and alpha 2-macroglobulin in adults with no neurological deficit. A prospective study was established, and 107 subjects (aged 18-89 yrs) were recruited from patients undergoing spinal anaesthesia or diagnostic myelography. A weak but significant positive correlation was found between the CSF/serum quotients and age for all the proteins studied, but with the exception of alpha 2-macroglobulin, these changes probably reflect age related falls in serum protein concentrations found in this study. alpha 2-Macroglobulin appears to be a sensitive indicator of barrier function for large populations, suggesting a subtle decline of BBB integrity with increasing age. This may be a true age-related change or could reflect an increased incidence of subclinical disease in an ageing population.

Fast and efficient method for detection and estimation of proteins.

A quick, simple, inexpensive and sensitive method is described to stain and quantitate proteins on nitrocellulose papers. The proteins may be spotted or transferred from polyacrylamide gels by Western blotting. The procedure involves non-radioactive iodination of the polypeptides by chloramine T and potassium iodide followed by detection of bound iodine with starch. The method is more sensitive and much quicker than Coomassie brilliant blue staining and may be used for quantitation or detection of proteins in unknown samples. Another major advantage of this procedure is that ionic or nonionic detergents, although at higher concentrations causing the sample to disperse more broadly in the membranes, do not affect the staining procedure. Further, this method may be used for detection of proteins bound to papers that have high affinity for proteins such as the Zeta probe membranes.