Magnetization and harmonic response of YBa2Cu3O7- delta :Ag composites.
Explore the source record for details and available documents.
Journal Article↗
Biomedical subjects
A Mitra
Publications and source records attributed to A Mitra.
A novel model to assess developmental toxicity of dihaloalkanes in humans: bioactivation of 1,2-dibromoethane by the isozymes of human fetal liver glutathione S-transferase.
Glutathione S-transferase (GST) isozymes from human fetal liver (16-18 weeks gestation) were purified by affinity chromatography followed by ion-exchange high performance liquid chromatography (HPLC). The purified isozymes were used to investigate toxicity of 1,2-dibromoethane(EDB) in an in vitro model of rat embryos in culture as passive targets. At least five isozymes of GST were found in the human fetal liver. Two anionic forms [pI values 5.5 (P-2) and 4.5 (P-3)] and one basic form [pI value 8.7 (P-6)] were clearly separated. The presence of two near-neutral forms was also identified. All the isozymes of the human fetal liver GSTs tested metabolized EDB (specific activities were 2.1, 7.0, and 2.0 mumol of GSH consumed/min/mg protein for P-2, P-3, and P-6 isozymes, respectively). Covalent binding of EDB to DNA and protein was 144% and 212% higher, respectively, with the P-3 anionic isozyme when compared to the P-6 basic isozyme of GST. No covalent binding to either protein or DNA was observed with the P-2 isozyme. EDB bioactivation by the GST isozyme P-3 (15 units; 1 unit = 1 nmol of GSH consumed/min) resulted in toxicity to cultured rat embryos. Significant reductions of crown rump length, yolk sac diameter, and the composite score of morphological parameters (Brown and Fabro method) were observed. The central nervous system, optic and olfactory systems, and the hind limb were most significantly affected. The results of this investigation suggest that EDB may be classified as a suspected developmental toxicant in humans.
Animals↗
Rat hepatic glutathione S-transferase-mediated embryotoxic bioactivation of ethylene dibromide.
The embryotoxic effects of ethylene dibromide (EDB) bioactivation, mediated by purified rat liver glutathione S-transferases (GST), were investigated using rat embryos in culture. Significant EDB metabolism was observed with rat liver GST purified by affinity chromatography (specific activity of 188 +/- 11.3 nmol/min/mg protein). The reaction was enzymatic in nature and the conjugation rate was proportional to the concentration of EDB (up to 0.75 mM) and the enzyme present in the reaction medium. EDB activation by 100 units (1 unit = 1 nmol of glutathione consumed per min) of purified rat liver GST caused a significant reduction in general development as measured by crown-rump length, yolk sac diameter, somite number, and the composite score for different morphological parameters (Brown and Fabro methodology). Structures most significantly affected were the central nervous and olfactory systems as well as the yolk sac circulation and allantois. The results of this study clearly indicate that under in vitro conditions, bioactivation of EDB by GST can lead to embryotoxicity.
Animals↗
Postpartum paravaginal hematoma and lower-extremity infection.
We report a case of infection of the lower extremity after a normal vaginal delivery. The infection originated in an occult obturator internus muscle hematoma, and diagnosis was based on a clinical suspicion and characteristic findings on computerized tomography scan. These findings permitted prompt surgical drainage, debridement, and antibiotic therapy and resulted in a successful outcome.
Adult↗
Inhibition of human term placental and fetal liver glutathione-S-transferases by fatty acids and fatty acid esters.
Glutathione-S-transferase (GST) activity from human term placenta and human fetal liver towards 1-chloro-2,4-dinitrobenzene as the second substrate was significantly inhibited by the saturated fatty acids, stearic (SA) and palmitic (PA) acids and fatty acid esters, ascorbyl stearate (Asc-S) and ascorbyl palmitate (Asc-P). The nature of inhibition of human placental GST was competitive towards CDNB with Ki values of 3.1, 10.0, 13.5 and 18.5 microM for Asc-S, Asc-P, PA and SA, respectively. The inhibitory effect of Asc-S on human term placental GST was reversible. I50 values for Asc-S, Asc-P, SA and PA were 15, 45, 83 and 78 microM, respectively, for partially purified human fetal liver GSTs and 21, 6, 88 and 117 microM, respectively, for partially pure rat liver GSTs. The evidence suggests that Asc-S, Asc-P, SA and PA are potent inhibitors especially of the pi-class of GST.
Animals↗
Rural-to-urban migration, urban workforce and tertiary sector employment: inter-relationship.
"In this study, it is argued that the rural to urban migration rate is both influenced by and influences the workforce participation rate and the level of service employment in the cities." The geographical focus is on India.
Asia↗
Dose, time and route dependency of the induction of rat hepatic ornithine decarboxylase by 12-tetradecanoylphorbol 13-acetate.
Ornithine decarboxylase (ODC) activity, the rate limiting enzyme in polyamine biosynthesis, was determined after 12-O-tetradecanoylphorbol 13-acetate (TPA) administration to female Sprague-Dawley rats. The extent of induction depended on the dose, exposure, time and route of administration. The most effective dose for ODC induction by the intraperitoneal route was 40 ug TPA/kg which caused 3-5 fold ODC induction. Maximal ODC induction occurred in a narrow time band 5 hours after TPA administration. TPA had no adverse effects on hepatic DNA (measured by alkaline elution), cytochrome P-450 content and reduced glutathione content or serum alanine aminotransferase (SGPT) activity.
Administration, Oral↗
Studies on induction of metachromasy in cationic dye pinacyanol chloride by Klebsiella K7 capsular polysaccharide.
The acidic capsular polysaccharide isolated from Klebsiella K7 induced metachromasy in the cationic dye pinacyanol chloride indicating its chromotropic character. Interaction of the biopolymer with the cationic dye was studied by visible absorption spectrophotometry, and thermodynamic parameters of the interaction evaluated. The polymer induced a metachromatic blue shift in the spectrum from 600 nm to 495 nm. The spectral changes were studied during interaction of the dye with the polymer at different polymer/dye molar ratios (P/D = 0 approximately 50). Effects of co-solvents on the stability of the dye-polymer compound were studied. A complete reversal of metachromasy was observed upon addition of different alcohols and urea solution. Thermodynamic parameters obtained from the spectral data indicated chromotropic character of the polymer in interacting with the cationic dye molecules in solution.
Carbocyanines↗
Absorption and fluorescence studies on interaction between cationic dyes and Klebsiella K7 capsular polysaccharide.
Interaction of cationic dyes, pinacyanol chloride, acridine orange and phenosafranin, with Klebsiella K7 capsular polysaccharide has been investigated by spectrophotometric and spectrofluorometric measurements. The acidic polysaccharide induce a metachromatic blue shift of the absorption band of pinacyanol chloride from 600 nm to 495 nm, indicating strong metachromasy. Stoichiometry of polyanion and dye cation (1:1.5) in the polymer-dye compound formed by the interaction between pinacyanol chloride dye and K7 polymer indicate that both glucuronic acid and pyruvic acid act as the potential anionic sites for interaction. Both spectrophotometric titration of pinacyanol chloride and spectrofluorometric titration of acridine orange and phenosafranin dyes by the polymer gave quite comparable equivalent weights for the polymer. Dye-polymer interaction studies indicated induction of metachromasy in the cationic dye by the anionic biopolymer, establishing its chromotropic character.
Cations↗
Genesis of thalassaemia intermedia.
Explore the source record for details and available documents.
Humans↗
Effect of ascorbic acid esters on hepatic glutathione levels in mice treated with a hepatotoxic dose of acetaminophen.
Acetaminophen (APAP) with or without ascorbyl stearate (AS) or ascorbyl palmitate (AP) was administered by gavage to male Swiss-Webster mice at a dose of 600 mg/kg for each chemical. The biochemical markers of hepatotoxicity, serum transaminases (serum glutamate pyruvate transaminase [SGPT], serum glutamate oxaloacetic transaminase [SGOT]) and serum isocitrate dehydrogenase (SICD) activities were monitored after APAP and APAP + AP or AS dosing. There were significant reductions in serum transaminase and SICD activities in the APAP- + ascorbate ester-treated animals as compared to APAP-positive controls. Oral coadministration of APAP with AP or AS did not prevent the initial hepatic GSH depletion (15 min-4 hr postdosing). However, hepatic GSH content began to rise in the APAP + AS or AP-treated animals at 4 hr and reached control values within 12 hr postdosing. Urinary mercapturate conjugates were also significantly higher in the APAP + AP or AS-treated animals as compared to APAP alone when measured over a 60-min postdosing period. Plasma sulfobromophthalein (BSP) retention was approximately eight times higher in APAP-treated animals as compared to the APAP + ascorbate ester treatments indicating maintenance of hepatic excretory functions in presence of AP or AS. Prior depletion of hepatic GSH by diethyl maleate (DEM) did not alter hepatoprotective effects of AP or AS in the presence of APAP. Hepatic ascorbate levels also peaked at 4 hours after APAP + AP or AS treatments. The possible role of L-ascorbic acid esters in GSH regeneration following co-administration of a hepatotoxic dose and APAP is discussed.
Acetaminophen↗
Inhibition of hepatic glutathione-S-transferases by fatty acids and fatty acid esters.
Micromolar concentrations of polyunsaturated fatty acids and ascorbate esters of saturated fatty acids were found to cause a marked inhibition of rat and mouse hepatic glutathione-S-transferase (GST) activity towards 1-chloro-2,4-dinitrobenzene. Arachidonic acid was approximately 25 times more potent in inhibiting rat GST than palmitic acid which was the least effective. Both linoleic and arachidonic acids did not inhibit rat liver GST when ethacrynic acid was used as substrate while the reverse was true with 1,2-dichoro-4-nitrobenzene. In contrast, all the chemicals tested inhibited rat liver GST activity towards 4-nitropyridine N-oxide, indicating isozyme specificity.
Animals↗
The effects of nicotinamide and hyperbaric oxygen on skin flap survival.
Hyperbaric oxygen has been established as an acceptable treatment for the chronic healing wound. Nicotinamide has been shown to be angiogenic and accelerate the physiologic process following wounding. Therefore both nicotinamide and hyperbaric oxygen were evaluated to enhance flap survival in an island pedicle skin flap model. These two treatment modalities were evaluated alone and in combination to assess if there is an addictive effect to enhance flap survival. Forty Sprague-Dawley male rats (weight 300-350 grams) were treated for 14 days preoperatively 1 day post-operatively with either 400 mg of nicotinamide i.p. or saline i.p. On day 14, a 7 X 7 cm island pedicle skin flap was elevated ligating the left inferior epigastric neurovascular pedicle and were sutured in their normal position. Twenty animals then underwent hyperbaric oxygen treatments. Forty-eight hours post-operatively animals were re-anesthetized and were given a single injection of fluorescein (25 mg/kg) via the tail vein. The % survival of the flap and SEM of the groups are as follows: Saline 45.67 +/- 31.14, nicotinamide 85.30 +/- 9.24, saline-hyperbaric oxygen 76.70 +/- 9.42 and nicotinamide-hyperbaric oxygen 90.86 +/- 3.94 with statistical significance of p less than 0.01. Nicotinamide appears to be another acceptable therapeutic modality in the management of the acceleration of wound healing.
Animals↗
Effect of sublethal electrocution on some haematological parameters in Rattus norvegicus.
Explore the source record for details and available documents.
Animals↗
Hydrogen peroxide: a potent activator of dioxygenase activity of soybean lipoxygenase.
Hydrogen peroxide, an ubiquitous biologically occurring peroxide, was found to stimulate the dioxygenase activity of soybean lipoxygenase at the physiologically attainable concentration. The increase in enzyme specific activity was directly proportional to hydrogen peroxide concentration up to 0.5 nM. A decrease in the stimulation of dioxygenase activity was observed at higher concentrations. At low enzyme concentration up to 28-fold stimulation was noted when the formation of lipid hydroperoxide was monitored spectrophotometrically. The stimulation was further confirmed by increased oxygen uptake. It is proposed that the mechanism for in vivo activation involves hydrogen peroxide.
Hydrogen Peroxide↗
Mirex induces ornithine decarboxylase in female rat liver.
Ornithine decarboxylase, the rate-limiting enzyme in polyamine synthesis, was significantly induced in female rat liver following oral administration of the pesticide mirex. After dual oral exposure (120 mg/kg of mirex; 21 and 4 hr prior to sacrifice), ornithine decarboxylase activity in rat liver cytosol was 70-fold higher than control values. A single oral dose of mirex (180 mg/kg) induced hepatic ornithine decarboxylase activity 55-fold over controls. After a single oral dose of mirex the maximal induction of ODC activity occurred at 36 hr. Mirex is an unusually potent and long-lasting inducer of rat hepatic ornithine decarboxylase activity.
Animals↗
Free vascularized tissue transfer for limb salvage in peripheral vascular disease.
In patients with tissue necrosis, higher limb salvage rates can be accomplished with free tissue transfers performed by a vascular and plastic surgeon team. We treated 10 patients with severe ischemic soft tissue defects in their legs with radical debridement and free tissue transfer alone (two patients) or after revascularization (eight patients). Arteriography was performed to plan revascularization to evaluate bypass results, and to identify appropriate recipient vessels for free tissue transfer. Soft tissue defects treated with free tissue transfer included nonhealing amputation sites in five patients and proximal skin and muscle necrosis in the remaining patients, one of which resulted in an exposed in-situ graft in one leg. One patient underwent a distal bypass specifically to provide arterial inflow for free tissue transfer, whereas seven other patients received free tissue transfers following bypass due to persistently nonhealing wounds. The remaining two patients had diabetes mellitus with necrosis near a major joint with nonhealing amputation sites. Free tissue transfers were taken from the latissimus dorsi in six patients, and from the gracilis, rectus abdominis, rectus femoris, and scapula flaps in other patients. Recipient vessels for free tissue transfers were the external iliac artery (one patient), saphenous vein bypass grafts (two patients), popliteal artery (one patient), posterior tibial (three patients), and dorsalis pedis vessels (three patients). Eight of the 10 flaps were viable at follow-up (four months-six years), with a mean follow-up of 20 months. One patient underwent above-knee amputation 15 months after operation and one underwent below-knee amputation three years later due to central flap necrosis. The remainder achieved functional limb salvage allowing patients to resume ambulation. Vascular surgeons should consider free tissue transfer in patients with nonhealing soft tissue defects following optimal revascularization to further extend our ability to salvage the threatened limb.
Adult↗
Chromotropic character of bacterial acidic polysaccharides: Part III--Interaction of cationic dye pinacyanol chloride with Klebsiella K15 capsular polysaccharide.
Interaction of cationic dye pinacyanol chloride with the acidic capsular polysaccharide isolated from Klebsiella serotype K15 has been investigated by spectral measurements. Klebsiella K15 polysaccharide consists of hexasaccharide repeating units containing one residue each of glucuronic acid and glucose, and four residues of galactose. Glucuronic acid acts as the potential anionic site and the biopolymer interacts with the dye cations. It induces metachromasy in the dye and a blue shift of about 100 nm is observed in the visible absorption spectrum of the dye. Spectral measurements have been carried out at different polymer/dye molar ratios. Stoichiometry of polymer and dye in the polyanion-dye compound (1:1) indicates that every potential anionic site of the polyanion is associated with the dye cation, and stacking conformation is thus suggested. Effect of different non-aqueous solvents in reversing metachromasy has also been studied. Interaction studies exhibit chromotropic character of the biopolymer.
Bacterial Capsules↗