Effect of Lower Doses of Vanadate in Combination with Azadirachta indica Leaf Extract on Hepatic and Renal Antioxidant Enzymes in Streptozotocin-Induced Diabetic Rats

The present study was undertaken to investigate short-term (21 days) effects of oral administration of Azadirachta indica leaf extract and vanadate, separately and in combination, on the activities of antioxidant enzymes in streptozotocin-induced diabetic rats. Vanadate is a remarkable antidiabetic agent and shows insulin mimetic effect. However, severe toxicity is associated with vanadate when used in high concentration while at lower concentration the hypoglycemic property of vanadate is reduced. So, we used a low dose of vanadate in combination with A. indica leaf extract and evaluated their effect on the antioxidant defense system. Streptozotocin-diabetic rats were treated separately with insulin, vanadate (0.6 mg/ml), A. indica, and with combined dose of vanadate (0.2 mg/ml) and A. indica. At the end of the experiment, rats were sacrificed and serum glucose levels and activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were determined in cytosolic fraction of liver and kidney. Diabetic rats showed hyperglycemic condition and alteration in antioxidant enzyme activities. Treatment with antidiabetic compounds resulted in the reduction of glucose levels and restoration of enzyme activities to normal. Results showed that combined treatment of vanadate and A. indica leaf extract was the most effective in normalizing altered antioxidant enzyme system.     

Identification and characterization of functional intermediates of stem bromelain during urea and guanidine hydrochloride unfolding

By comparing changes in enzyme activity with changes in spectral features for stem bromelain (EC.3.4.22.32) in the absence and presence of urea, Guanidine hydrochloride and ethanol; four intermediate states could be identified: two activity-enhanced state obtained in the presence of 5 M urea and 2 M GnHCl, termed X and X', respectively, and a third, similarly active state closely resembling the native protein in the presence of 8-9 M urea, termed Y. The enhanced activity of these states is due to local conformational changes accompanied by increased dynamics in the active site. Further, the enzyme does not lose its activity after substantial tertiary structure changes in 8-9 M urea (Y state), suggesting that active site containing domain is more resistant to chemical denaturation than the other structural domain. This makes stem bromelain and in general cysteine proteases an exception to the hypothesis that active site is the most labile part of enzyme.     

Amelioration of altered antioxidant status and membrane linked functions by vanadium andTrigonella in alloxan diabetic rat brains

Trigonella foenum graecum seed powder (TSP) and sodium orthovanadate (SOV) have been reported to have antidiabetic effects. However, SOV exerts hypoglycemic effects at relatively high doses with several toxic effects. We used low doses of vanadate in combination with TSP and evaluated their antidiabetic effects on antioxidant enzymes and membrane-linked functions in diabetic rat brains. In rats, diabetes was induced by alloxan monohydrate (15 mg/100 g body wt.) and they were treated with 2 IU insulin, 0.6 mg/ml SOV, 5% TSP and a combination of 0.2 mg/ml SOV with 5% TSP for 21 days. Blood glucose levels, activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), Na⁺/K⁺ ATPase, membrane lipid peroxidation and fluidity were determined in different fractions of whole brain after 21 days of treatment. Diabetic rats showed high blood glucose (P < 0.001), decreased activities of SOD, catalase and Na⁺/K⁺ ATPase (P < 0.01,P < 0.001 andP < 0.01), increased levels of GPx and MDA (P < 0.01 andP < 0.001) and decreased membrane fluidity (P < 0.01). Treatment with different antidiabetic compounds restored the above-altered parameters. Combined dose ofTrigonella and vanadate was found to be the most effective treatment in normalizing these alterations. Lower doses of vanadate could be used in combination with TSP to effectively counter diabetic alterations without any toxic effects.     

Influence of salts and alcohols on the conformation of partially folded intermediate of stem bromelain at low pH

The effect of salts and alcohols was examined on the partially folded intermediate (PFI) state of stem bromelain reported at low pH (Haq, Rasheedi, and Khan (2002) European Journal of Biochemistry 269, 47-52) by a combination of optical methods like circular dichroism, intrinsic fluorescence and ANS binding. ESI mass spectrometry was also performed to see the effect, if any, on the overall tertiary structure of the protein. Increase in ionic strength by the addition of salts resulted in folded structures somewhat different from the native enzyme. Salt-induced intermediates are characterized by increase in helical content and a significantly reduced exposure of hydrophobic clusters relative to the state at pH 2.0. The emission wavelength maximum of intrinsic fluorescence was shifted towards that of native enzyme. ESI-MS data show decreased accessibility of ionizable/protonation sites suggestive of a folded structure. On the other hand, alcohol-induced intermediates though exhibiting increased helical content are apparently largely unfolded as observed by ESI. Thermal denaturation of a representative intermediate, each from the group of salts and alcohols examined, was also performed to check their relative stabilities. While the alcohol-induced state showed a cooperative thermal transition, the salt-induced state shows non-cooperative thermal denaturation.     

Phospholipid metabolism and protein kinase C mediated protein phosphorylation in dietary protein deficiency in rat lung

Nutritional deprivation of proteins decreases the protein kinase C (PKC) activity in rat lung. The activity of (PKC) is influenced by lipid metabolism. Changes in PKC activity may influence phosphorylation of its substrate proteins in the tissues. Therefore, alterations in phospholipid metabolism and PKC mediated protein phosphorylation in dietary protein deficiency in rat lung were envisaged. The study was conducted on rats fed on three different types of diet viz., casein (20% protein), deficient (4% protein, rice flour as source of protein) and supplemented (deficient diet supplemented with L-lysine and DL-threoning). Feeding of protein deficient diet caused reduction in incorporation of [3H] myo-inositol in the total phosphoinositides in lungs and an increase in total inositol phosphate pool. There was a significant reduction in the contents and turnover rate of phosphatidyl inositol and phosphatidyl inositol monophosphate. Supplementation of diet with L-lysine and DL-threonine had a reversing effect on total pool of phosphoinositides and, the metabolism of phosphatidyl inositol bisphosphate and phosphatidyl inositol. In phosphatidyl choline metabolism, the dietary protein deficiency led to a decrease in incorporation of [14C-methyl] choline-chloride in total phospholipids. In contrast, its incorporation increased in phosphatidyl choline pool. The contents of phosphatidyl choline and residue, incorporation of [14C-methyl] choline-chloride in them and their turnover rate also increased. Supplementation of diet had a reversal effect on most of these parameters. Phosphorylation of proteins of 84, 47, 35 and 16 kDa was identified to be mediated by PKC. In dietary protein deficiency, phosphorylation of all these proteins, except that of 47 kDa, increased. Supplementation of diet reversed the pattern except that of 84 kDa. The findings suggest that changes in phospholipid metabolism in dietary protein deficiency may effect the activity of PKC thereby influencing the phosphorylation of its substrate proteins and hence associated functions that may lead to pathophysiology of lung.     

Effects of inhaled corticosteroids on sputum cell counts in stable chronic obstructive pulmonary disease: a systematic review and a meta-analysis

Background

Whether inhaled corticosteroids suppress airway inflammation in chronic obstructive pulmonary disease (COPD) remains controversial. We sought to determine the effects of inhaled corticosteroids on sputum indices of inflammation in stable COPD.

Methods

We searched MEDLINE, EMBASE, CINAHL, and the Cochrane Databases for randomized, controlled clinical trials that used induced sputum to evaluate the effect of inhaled corticosteroids in stable COPD. For each chosen study, we calculated the mean differences in the concentrations of sputum cells before and after treatment in both intervention and control groups. These values were then converted into standardized mean differences to accommodate the differences in patient selection, clinical treatment, and biochemical procedures that were employed across original studies. If significant heterogeneity was present (p < 0.10), then a random effects model was used to pool the original data. In the absence of significant heterogeneity, a fixed effects model was used.

Results

We identified six original studies that met the inclusion criteria (N = 162 participants). In studies with higher cumulative dose (≥ 60 mg) or longer duration of therapy (≥ 6 weeks), inhaled corticosteroids were uniformly effective in reducing the total cell, neutrophil, and lymphocyte counts. In contrast, studies with lower cumulative dose (< 60 mg) or shorter duration of therapy (< 6 weeks) did not demonstrate a favorable effect of inhaled corticosteroids on these sputum indices.

Conclusions

Our study suggests that prolonged therapy with inhaled corticosteroids is effective in reducing airway inflammation in stable COPD.     

A neural network model for reconstructing EMG signals from eight shoulder muscles: consequences for rehabilitation robotics and biofeedback

This paper demonstrates the ability of a fully connected feed forward neural network (FFNN) using the backpropagation training algorithm to predict the electromyography (EMG) signal from eight muscles of the shoulder for both exercises not used for training and EMG signals from subjects not used for training. The network showed a good predictive ability for subjects not used for training (r(2) between 0.33 and 0.84) and for activities not used for training (r(2) between 0.56 and 0.89). This may have applications for patients, physical therapists and doctors to monitor patient performance by reviewing the level of agreement between the patient EMG and the predicted EMG. Coupled with traditional methods of evaluation, EMG can provide an excellent measure of how well a patient has responded or is responding to treatment. Incorporating robotic technology could facilitate the use of EMG as an input to an intelligent decision making algorithm used to increase or decrease the level of difficulty according to patient performance.