Effect of chitosan on lipid levels when administered concurrently with atorvastatin--a placebo controlled study

In a placebo controlled trialthe lipid lowering effects of chitosan, a unique dietary fibre, was assessed when given along with atorvastatin 10 mg in patients with chronic coronary heart disease. Altogether 100 patients were studied. They were randomly allocated in two groups of 50 patients each. Patients of group A received atorvastatin 10 mg before dinner plus 2 g/day chitosan in two divided doses. The groupB patients received atorvastatin 10 mg plus placebo. Patients were followed up for a period of 6 weeks. There was significant reduction in mean body weight in group A patients (3.14% versus 1,29% of body weight, p<0.05). There was also a significant rise in HDL cholesterol value (3.8% versus 1.07%, p=0.02) in group A patients. However, there was no significant reduction in the mean values of total cholesterol, LDL cholesterol and triglyceride in the two groups, although group A patients showed marginally lower values.

A study on micro-albuminuria--an independent risk factor for vasculopathy in diabetes mellitus

Diabetes is becoming a serious threat to combat felt among the doctors of the world. India, in partcular is a vulnerable country contributing maximum number of cases to the global diabetic pool. Macro-and microvascular complications are important causes of mortality and morbidity. Micro-albuminuria is a surrogate marker for detetion of vasculopathy for which early detection and aggressive treatment can reduce mortality and morbidity. A small study was conducted to identify the usefulness of this marker in our setting which can be used as a cost-effective tool for detecting the dreadful complication early. This study has demonstrated that in presence of micro-albuminuria the vascular complications of diabetes definitely increase and it is more relevant in cases of type 2 diabetes irrespective of other parameters rendering it to be a independent risk factor. It also indicates that presence of this marker along with vasculopathy is time dependent ie, more the duration of the disease more is the complication.

Comparison of microstructural evolution in Ti-Mo-Zr-Fe and Ti-15Mo biocompatible alloys

The microstructural evolution and attendant strengthening mechanisms in two biocompatible alloy systems, the binary Ti-15Mo and the quaternary Ti-13Mo-7Zr-3Fe (TMZF), have been compared and contrasted in this paper. In the homogenized condition, while the Ti-15Mo alloy exhibited a single phase microstructure consisting of large beta grains, the TMZF alloy exhibited a microstructure consisting primarily of a beta matrix with grain boundary alpha precipitates and a low volume fraction of intra-granular alpha precipitates. On ageing the homogenized alloys at 600 degrees C for 4 h, both alloys exhibited the precipitation of refined scale secondary alpha precipitates homogeneously in the beta matrix. However, while the hardness of the TMZF alloy marginally increased, that of the Ti-15Mo alloy decreased substantially as a result of the ageing treatment. In order to understand this difference in the mechanical properties after ageing, TEM studies have been carried out on both alloys in the homogenized and homogenized plus aged conditions. The results indicate that the omega precipitates dissolve on ageing in case of the Ti-15Mo alloy, consequently leading to a substantial decrease in the hardness. In contrast, the omega precipitates do not dissolve on ageing in the TMZF alloy and the precipitation of the fine scale secondary alpha leads to increased hardness.

Carotid intima media thickness: an independent marker for assessment of macrovascular risk in diabetic patients

In view of the global epidemic of diabetes with India being the hottest reservoir of the disease, it was tried to identify carotid intima media thickness as a surrogate marker for atherosclerosis in diabetic subjects. The study becomes more relevant because diabetes is now considered a disease of the endothelium and a risk equivalent of coronary atherosclerosis (paradigm shift). The study incorporated 41 normotensive patients of diabetes and 31 age and sex matched controls. Plasma glucose and lipid profiles were assessed in all and the carotid intima media thickness was measured. Results were statistically analysed for significance and correlation coefficient between values of plasma glucose and carotid intima media thickness. Results clearly showed that carotid intima media thickness abnormality can pick up atherosclerosis even if the lipid parameters are nearly normal. So it crystallises from this small study that, as a non-invasive test carotid intima media thickness is a better and early predictor of atherosclerosis in diabetic subjects. It also revealed the linear relationship between both fasting and postprandial blood sugar with carotid intima media thickness.

Button battery ingestion

Button batteries represent a special category of pediatric ingested foreign body because of the possibility of serious complications particularly if impacted in the esophagus. We report a case of a 3-year-old girl with severe mid esophageal burns due to a lodged battery. More awareness is required amongst physicians to avert such dangers and ensure prompt removal.

Dynamic surface tensiometry of tissues using Langmuir films

Langmuir monolayers are useful models of biomembranes as they allow simulation of biological conditions and rigorous thermodynamic analysis. This technique was used to characterize tissues at body temperature for the first time in our study. The organs studied include liver, kidney, stomach, testis, heart and brain from goat and certain human cancerous as well as their corresponding normal biopsies to reveal the potential of the tissue monolayer technique. Monolayers were formed on the surface of deionized water by spreading monolayer amounts of the tissue homogenates. The parameters calculated were minimum surface tension, relative lift off area, relative limiting area, compressibility and hysteresis area. Our results reveal that the parameters can differentiate between tissues obtained from different organs and were statistically significant using one-way ANOVA and Newman Keul's test (P<0.05). For example goat's stomach tissue had the lowest hysteresis area (DeltaG) value (27.6 microJ) whereas brain DeltaG value was nine folds higher than stomach value. Brain had the lowest minimum surface tension of 30.3+/-1.0 mN/m whereas stomach had a value of 40.5+/-0. 2 mN/m. Interestingly, the DeltaG values of human normal neck and esophageal tissues were 3.4 and 3.2 folds greater than that of their respective cancer tissues whereas the DeltaG values of vulval and breast cancer tissues were 4.6 and 4 folds greater than that of their respective normal tissues. While the gammamin values of neck cancer tissue showed 95% increase from normal tissue values, those of vulval and breast cancer tissues were 46 and 50% less compared to their respective normal tissue values. Though all the surface tensiometric parameters showed significant changes, minimum surface tension and hysteresis area were the most sensitive indicators of tissue types and diseased states. Further, the effects of therapeutics could also be monitored by this technique. This is evidenced by the post-radiotherapy tissue isotherms of neck and vulval cancers, where clinical radio-sensitivity was associated with a shift in the tensiometry towards their respective normal isotherms. The small sample amounts required, precision of the technique, very low within group variability, organ specificity and sensitivity to detect changes in diseased states make it a promising tool for prognostic evaluation of diseased states and monitoring effects of therapeutics. Further research is warranted in this promising and hitherto unexplored field of tissue tensiometry.

Effect of antitubercular drugs on dipalmitoylphosphatidylcholine monolayers: implications for drug loaded surfactants

The year long chemotherapy in pulmonary tuberculosis results in dose related side effects and may not reach atelectatic areas. On account of its spreading properties and the ability to re-expand atelectatic areas, exogenous surfactant may act as a pulmonary drug delivery agent. We investigated the interactions between antitubercular drugs and the main surfactant component, dipalmitoylphosphatidylcholine (DPPC) with the aim of developing more effective antitubercular drug loaded surfactants. The surface properties were evaluated using a Langmuir-Blodgett trough and Wilhelmy balance at 37 degrees C. Lung surfactant was modeled as DPPC monolayers. The isoniazid (INH)-DPPC combination in 1:1 ratio by weight significantly improved the adsorption of DPPC, reached a minimum surface tension of zero, formed a low compressibility film and required 32.7% area change to decrease surface tension from 30 to 10 mN/m. The triple drug (INH-rifampicin-ethambutol in 1:2:3 ratio by weight) DPPC combination when used in 1:1 or 1:2 ratios by weight also achieved surface properties superior to those of DPPC alone. A significant improvement in the adsorption was observed (surface tensions of 34.7 mN/m for 1:1 and 32.0 mN/m for 1:2 triple drug: DPPC combinations in the first second), and the films had low compressibility reaching a minimum surface tension of zero on compression. Thus, we observed statistically significant improvements in all the surface parameters and we feel encouraged to continue developing a tuberculosis therapy consisting of surfactant liposomes carrying antitubercular drugs.

Sustained antiproliferative mechanisms by RB24, a targeted precursor of multiple inhibitors of epidermal growth factor receptor and a DNA alkylating agent in the A431 epidermal carcinoma of the vulva cell line

Recently, with the purpose of enhancing the potency of epidermal growth factor receptor (EGFR)-based therapies, we designed a novel strategy termed ‘Cascade-release targeting’ that seeks to develop molecules capable of degrading to multiple tyrosine kinase (TK) inhibitors and highly reactive electrophiles, in a stepwise fashion. Here we report on the first prototype of this model, RB24, a masked methyltriazene, that in addition to being an inhibitor on its own was designed to degrade to RB14, ZR08, RB10+a DNA alkylating methyldiazonium species. The cascade degradation of RB24 requires the generation of two reactive electrophiles: (a) an iminium ion and (b) a methyldiazonium ion. Thus, we surmise that these species could alkylate the active site of EGFR, thereby irreversibly blocking its action and that DNA damage could be induced by the methyldiazonium. Using the EGFR-overexpressing human epidermoid carcinoma of the vulva cell line, A431, we demonstrate herein that (a) RB24 and its derived species (e.g. RB14, ZR08) irreversibly inhibit EGFR autophosphorylation, (b) RB24 induced significant levels of DNA strand breaks, (c) sustained inhibition of EGFR by RB24 was associated with blockade of MAPK activation and c-fos gene expression, (d) RB24 induced irreversible cell growth inhibition with a 100-fold greater potency than Temodal™, a clinical methyltriazene. The pronounced growth inhibitory potency of RB24 was attributed to its ability to simultaneously damage DNA and irreversibly block EGFR TK activity.

A study of bone mineral density in diabetes mellitus in eastern India

To measure bone mineral density in diabetic patients at the time of clinical diagnosis of diabetes mellitus and to find out correlation, if any, with microvascular complication of diabetes mellitus and glycosylated haemoglobin, a study was conducted at Medical College and Hospital, Kolkata among 138 cases of diabetes and 212 controls. All patients were screened for ophthalmoscopy, routine blood and urine examinations. Bone ultrasound attenuation study of the calcaneus was performed in all cases. The bone ultrasound attenuation result was compared to a mean normal population result and expressed as Z score and T score. The age of diabetic patients varied from 11 years to 70 years. Of 138 diabetics, 32 (23.18%) had type 1 diabetes and rest type 2 diabetes. Forty-two diabetic patients had retinopathy, 42 nephropathy and 48 had neuropathy. Glycosylated haemoglobin was above 7% in 124 patients. The broadband ultrasound attenuation of type 1 diabetics ranged from 38 to 95 dB/MHz and in type 2 it was 35 to 104 dB/MHz. There was no statistically significant correlation between neuropathy, nephropathy, retinopathy and bone mineral density status. It was also found no correlation between glycosylated haemoglobin values and ultrasound attenuation.

DNA sequence and analysis of human chromosome 9

Chromosome 9 is highly structurally polymorphic. It contains the largest autosomal block of heterochromatin, which is heteromorphic in 6-8% of humans, whereas pericentric inversions occur in more than 1% of the population. The finished euchromatic sequence of chromosome 9 comprises 109,044,351 base pairs and represents >99.6% of the region. Analysis of the sequence reveals many intra- and interchromosomal duplications, including segmental duplications adjacent to both the centromere and the large heterochromatic block. We have annotated 1,149 genes, including genes implicated in male-to-female sex reversal, cancer and neurodegenerative disease, and 426 pseudogenes. The chromosome contains the largest interferon gene cluster in the human genome. There is also a region of exceptionally high gene and G + C content including genes paralogous to those in the major histocompatibility complex. We have also detected recently duplicated genes that exhibit different rates of sequence divergence, presumably reflecting natural selection.

The DNA sequence and comparative analysis of human chromosome 10

The finished sequence of human chromosome 10 comprises a total of 131,666,441 base pairs. It represents 99.4% of the euchromatic DNA and includes one megabase of heterochromatic sequence within the pericentromeric region of the short and long arm of the chromosome. Sequence annotation revealed 1,357 genes, of which 816 are protein coding, and 430 are pseudogenes. We observed widespread occurrence of overlapping coding genes (either strand) and identified 67 antisense transcripts. Our analysis suggests that both inter- and intrachromosomal segmental duplications have impacted on the gene count on chromosome 10. Multispecies comparative analysis indicated that we can readily annotate the protein-coding genes with current resources. We estimate that over 95% of all coding exons were identified in this study. Assessment of single base changes between the human chromosome 10 and chimpanzee sequence revealed nonsense mutations in only 21 coding genes with respect to the human sequence.

Activation of methionine synthase by insulin-like growth factor-1 and dopamine: a target for neurodevelopmental toxins and thimerosal

Methylation events play a critical role in the ability of growth factors to promote normal development. Neurodevelopmental toxins, such as ethanol and heavy metals, interrupt growth factor signaling, raising the possibility that they might exert adverse effects on methylation. We found that insulin-like growth factor-1 (IGF-1)- and dopamine-stimulated methionine synthase (MS) activity and folate-dependent methylation of phospholipids in SH-SY5Y human neuroblastoma cells, via a PI3-kinase- and MAP-kinase-dependent mechanism. The stimulation of this pathway increased DNA methylation, while its inhibition increased methylation-sensitive gene expression. Ethanol potently interfered with IGF-1 activation of MS and blocked its effect on DNA methylation, whereas it did not inhibit the effects of dopamine. Metal ions potently affected IGF-1 and dopamine-stimulated MS activity, as well as folate-dependent phospholipid methylation: Cu(2+) promoted enzyme activity and methylation, while Cu(+), Pb(2+), Hg(2+) and Al(3+) were inhibitory. The ethylmercury-containing preservative thimerosal inhibited both IGF-1- and dopamine-stimulated methylation with an IC(50) of 1 nM and eliminated MS activity. Our findings outline a novel growth factor signaling pathway that regulates MS activity and thereby modulates methylation reactions, including DNA methylation. The potent inhibition of this pathway by ethanol, lead, mercury, aluminum and thimerosal suggests that it may be an important target of neurodevelopmental toxins.

The DNA sequence and analysis of human chromosome 6

Chromosome 6 is a metacentric chromosome that constitutes about 6% of the human genome. The finished sequence comprises 166,880,988 base pairs, representing the largest chromosome sequenced so far. The entire sequence has been subjected to high-quality manual annotation, resulting in the evidence-supported identification of 1,557 genes and 633 pseudogenes. Here we report that at least 96% of the protein-coding genes have been identified, as assessed by multi-species comparative sequence analysis, and provide evidence for the presence of further, otherwise unsupported exons/genes. Among these are genes directly implicated in cancer, schizophrenia, autoimmunity and many other diseases. Chromosome 6 harbours the largest transfer RNA gene cluster in the genome; we show that this cluster co-localizes with a region of high transcriptional activity. Within the essential immune loci of the major histocompatibility complex, we find HLA-B to be the most polymorphic gene on chromosome 6 and in the human genome.

Artificial vitreous replacements

Vitreoretinal pathologies remain the significant leading cause of blindness, after cataract, throughout the world. Biomaterials as a whole, and vitreous substitutes in particular, have had a major role to play in vitreoretinal surgery. History has witnessed the advent of vitreous substitutes from collagen and hyaluronic acid to gases, silicone oils and perfluorocarbon liquids and now to polymer hydrogels. Such a long list only underscores the fact that we have been found wanting in our quest for an ideal vitreous substitute. This review focuses on the merits and demerits of various vitreous substitutes, which have been tried to date, clinical as well as experimental. The properties required of an ideal substitute and the performance of the vitreous substitutes with respect to these criteria have been described. Finally, the concluding note dwells on the future directions for biomaterial research in the posterior segment of the eye and undermines the role of tissue engineering in vitreoretinal regeneration.

Broom stick dermatitis

Soft plastic handle cover of newly produced broom stick causing contact dermatitis in reported.

Controlling the reactivity of radical intermediates by coenzyme B(12)-dependent methylmalonyl-CoA mutase

Adenosylcobalamin or coenzyme B(12)-dependent enzymes are members of the still relatively small group of radical enzymes and catalyse 1,2-rearrangement reactions. A member of this family is methylmalonyl-CoA mutase, which catalyses the isomerization of methylmalonyl-CoA to succinyl-CoA and, unlike the others, is present in both bacteria and animals. Enzymes that catalyse some of the most chemically challenging reactions are the ones that tend to deploy radical chemistry. The use of radical intermediates in an active site lined with amino acid side chains that threaten to extinguish the reaction by presenting alternative groups for abstraction poses the conundrum of how the enzymes control their reactivity. In this review, insights into this issue that have emerged from kinetic, mutagenesis and structural studies are described for methylmalonyl-CoA mutase.

Purification and characterization of maltooligosaccharide-forming amylase from Bacillus circulans GRS 313

A maltooligosaccharide-forming amylase that hydrolyzes starch into maltotriose and maltopentaose was found in the culture filtrate of a strain of Bacillus circulans GRS 313 isolated from local soil. The enzyme was purified by organic solvent fractionation, Sephadex G-100 gel filtration and CM-Sephadex column chromatography. Optimum pH and temperature of amylase were evaluated using response surface methodology (RSM) and were found to be 48 degrees C and 4.9, respectively. The enzyme was stable up to 60 degrees C and its pH stability was in the range of 5.0-8.0. The Km and Vmax of the amylase with starch were 11.66 mg/ml and 68.97 U, respectively, and the energy of activation, Ea, was 7.52 kcal/mol. Dextrin inhibited the enzyme competitively, with a Ki of 6.1 mg/ml, and glucose caused noncompetitive inhibition with a Ki of 9.5 mg/ml. The enzyme was inhibited by Hg2+, Mn2+, Fe3+ and Cu2+ and enhanced by Co2+ and Mg2+. EDTA reversed the inhibitory effect of the metals. Paper chromatographic and high-performance liquid chromatography analysis of the products of the amylolytic reaction showed the presence of maltotriose, maltotetraose, maltopentaose, maltose and glucose in the starch hydrolysate.