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Biomedical subjects

A Mitra

Publications and source records attributed to A Mitra.

At least 109 records · Page 6Linked to original sources
PubMed1990

A study of aluminum phosphide (AlP) poisoning with special reference to electrocardiographic changes.

Ninety patients with aluminum phosphide poisoning have been studied over a period of 3 years. Epigastric pain and vomiting were the common initial clinical features, followed 12 to 24 hours later by cardiogenic shock, oliguria, altered mental state and respiratory distress. Death occurred within 24 to 72 hours presumably due to poison-induced toxic chemical myocarditis as reflected by electrocardiographic changes. The overall mortality was 63.3%. Intravenous magnesium sulphate, probably due to its membrane stabilizing action, appears to be related to the reduction in mortality from 90% to 52% in the latter 62 cases.

Adolescent↗
PubMed1989

Three distinct regulatory elements comprise the upstream promoter region of the nopaline synthase gene.

Fine deletion mutants were generated in the upstream control region of the nopaline synthase (nos) promoter to define the position and role of upstream regulatory elements. The results indicated that the 8 bp sequence (CAGAAACC) at -106/-113 and its inverted repeat (GGTTTCTG) at -140/-147 are important for promoter function. The downstream element appears more important than the upstream element since deletion of the former reduced promoter activity more significantly than deletion of the latter. Deletion of the element alone, however, did not abolish promoter function, whereas, deletion of the 10 bp potential Z-DNA-forming (Z) element located between the repeat elements nullified promoter activity. Therefore, it appears that the Z element is an essential upstream regulator and the repeated elements are upstream modulators of the nos promoter. These elements are functionally distinct since alteration of stereospecificity or insertion of short oligonucleotides between the elements did not significantly influence promoter activity. These regulatory elements were unable to function from 200 bp upstream of the CCAAT-TATA box region.

Amino Acid Oxidoreductases↗
PubMed1989

Functional analysis of the 3' control region of the potato wound-inducible proteinase inhibitor II gene.

Proteinase inhibitor genes are expressed strongly in specific plant tissues under both developmental and environmental regulation. We have studied the role of the 3' control region of the potato proteinase inhibitor II gene (PI-II) that is inducible in leaves in response to herbivore attacks or other severe wounding. Comparison of the terminator from the PI-II gene with two different terminators from the 6b and 7 genes, driven by a common PI-II promoter-cat fusion molecule, indicated that the PI-II terminator provided the most efficient expression of cat. The PI-II terminator also caused a significantly elevated cat gene expression driven by the cauliflower mosaic virus 35S promoter. The increase in the level of expression is probably not due to the presence of an enhancer element in the PI-II terminator region, but to cis-acting elements involved in mRNA processing or stability. Both transient and stable transformation analyses of the deletion mutants in the 3'-flanking sequence indicated that about a 100-base pair DNA fragment surrounding the polyadenylation site is essential for the efficient gene expression. This region seems to consist of several regulatory elements, including the conserved sequence, CGTGTCTT, which is located 9 bases downstream from the polyadenylation site. The elements appear to contribute to the increased stability of mRNAs containing the PI-II terminator.

Amino Acid Sequence↗
PubMed1989

Carpal tunnel: MR imaging. Part II. Carpal tunnel syndrome.

The magnetic resonance (MR) images of 14 wrists of patients with carpal tunnel syndrome (CTS) were studied. Four general findings visible regardless of the cause of CTS included swelling of the median nerve, best evaluated at the level of the pisiform bone; flattening of the median nerve, most reliably judged at the hamate level; palmar bowing of the flexor retinaculum, best visualized at the level of the hamate bone; and increased signal intensity of the median nerve on T2-weighted images. Findings related to cause were tendon sheath edema in traumatic tenosynovitis, synovial hypertrophy in rheumatoid tenosynovitis, a ganglion cyst, and excessive amount of fat within the carpal tunnel, a persistent median artery, and a large adductor pollicis muscle. Knowledge of these findings may permit more rational choice of treatment. In four cases in which symptoms persisted after surgery, findings valuable in explaining or predicting the failure included incomplete incision of the flexor retinaculum, excessive fat within the carpal tunnel, persistent neuritis of the median nerve, and development of neuromas.

Adult↗
PubMed1989

Nicotinamide enhances skin flap survival.

The effects of nicotinamide in an abdominal island pedicle skin flap were examined. A 7 x 7 cm island pedicle skin flap ligating the left inferior neurovascular pedicle was created on 50 male Sprague Dawley rats (250-275 grams) that were divided into five groups. Animals received either 0.6 cc of saline or doses of nicotinamide for 16 days (14 days preoperatively and 2 days postoperatively): 25 mg b.i.d., 50 mg b.i.d., 100 mg b.i.d. or 200 mg b.i.d. Forty-eight hours postoperatively each animal received 25 mg of Fluorescein via the tail vein. The area of necrosis was visualized and quantified and is presented as % survival. A one factor Fisher PLSD test was performed with a statistical significance of p less than 0.05 with the results as follows: saline 58.8%, 25 mg 68.6%, 50 mg 82%, 100 mg 80.8%, and 200 mg 86%. From this data it would appear that the angiogenic factor nicotinamide may increase random flap survival.

Animals↗
PubMed1989

Dioxygenase and peroxidase activities of soybean lipoxygenase: synergistic interaction between linoleic acid and hydrogen peroxide.

The interaction of H2O2 with soyabean lipoxygenase was investigated in the presence of linoleic acid. Dioxygenase activity was significantly higher at pH 9.0 than at pH 6.0. H2O2 at concentrations less than 1.0 nM stimulated linoleic acid oxidation synergistically and the magnitude of synergism was higher at pH 9.0. Linoleic acid dependent peroxidase activity towards benzidine, guaiacol, tetramethylbenzidine (TMBD) and tetramethylphenylenediamine (TMPD) was higher at pH 9.0, whereas pyrogallol and ABTS oxidation rates were higher at pH 6.0. H2O2 supported oxidation of benzidine, guaiacol, pyrogallol and ABTS was higher at pH 6.0, whereas TMPD, TMBD exhibited higher oxidation rates at pH 9.0. H2O2 in the presence of linoleic acid produced synergism in xenobotic metabolism and depending upon the substrate in question upto 11-fold increase in oxidation rate was noted.

Drug Synergism↗
PubMed1989

Cholera epidemic and natural disasters; where is the link.

In May 1985, a cyclone and tidal surge devastated Sandwip, an island off the Southern Corner of Bangladesh. Within one week after this disaster a cholera epidemic broke out. It resulted in 12,194 registered cases and 51 deaths. The factors contributing to the occurrence of the epidemic are analyzed.

Bangladesh↗
PubMed1988

Role of iron in the enhancement by Agrobacterium tumefaciens infection in mice.

Microorganisms require iron for their growth and usually compete with their host for available iron from the system. Iron supplementation to host causes an increase of available iron both to host and to potential microbial invaders and favours the latter more than the former as the bacteria release siderophores which are responsible for iron transport mechanism. In view of this observation a study was done to deal with the distribution of storage and injected iron given as an overload within a physiological pool, taking mice as the host, with a correlation to its utilization by Agrobacterium tumefaciens and with bacterial growth and multiplication. The results obtained help in understanding the host--parasite relationships, regarding bacterial virulence and infection and the growth-promoting effect of iron, as iron promoted the development and progression of serum-exposed A. tumefaciens in mice.

Animals↗
PubMed1988

Influence of ascorbic acid esters on acetaminophen-induced hepatotoxicity in mice.

Groups of male Swiss-Webster mice were gavaged with acetaminophen (APAP), APAP + ascorbyl stearate (AS), or APAP + ascorbyl palmitate (AP) at a dose of 600 mg/kg for each chemical. APAP alone caused a significant increase in liver weight/body weight ratio and hepatic glutathione (GSH) depletion. Co-administration of the ascorbate esters AP or AS with APAP prevented an increase in liver weight/body weight ratios and hepatic glutathione depletion. APAP + AS treatments caused significantly greater reductions in rectal temperature at 15-30 min post-dosing periods when compared to APAP + AP or AS treatments. Blood levels of APAP had the same relationship. The study indicates a correlation between APAP blood levels and antipyretic effect of APAP + AS and APAP + AP coadministrations. While both ascorbate esters probably afford protection against APAP-induced hepatotoxicity in mice by reducing the reactive intermediate back to the parent compound, the APAP + AS combination provides better therapeutic efficacy as an antipyretic at the 15-30 min post-dosing periods.

Acetaminophen↗
PubMed1988

Organ-specific and developmental regulation of the nopaline synthase promoter in transgenic tobacco plants.

Control regions of the nopaline synthase (nos) gene have been widely used to express foreign genes in plants since the promoter is active in a wide variety of plant tissues. We report here the characteristics of the nos promoter activity in transgenic tobacco (Nicotiana tabacum) plants at various developmental stages. The promoter was highly active in the lower parts of a plant and gradually decreased in the upper parts. This vertical gradient was maintained throughout plant growth until the flowering stage when the overall promoter strength decreased significantly in the vegetative organs. However, in various flower organs, the nos promoter activities increased dramatically. Higher activity was observed in calyx, corolla, and stamens although the maximum promoter activity in each organ was found at different stages of flower development. The promoter activity in pistils was low and gradually increased in the ovaries after anthesis. In developing fruits, the nos promoter activity was strongly induced during the mid-stage of embryogenesis. These results indicate that the expression of the nos promoter is developmentally regulated and organ specific in transgenic tobacco plants.

Journal Article↗
PubMed1987

Organic emissions from coal pyrolysis: mutagenic effects.

Four different types of coal have been pyrolyzed in a laminar flow, drop tube furnace in order to establish a relationship between polycyclic aromatic compound (PAC) evolution and mutagenicity. Temperatures of 900K to 1700K and particle residence times up to 0.3 sec were chosen to best simulate conditions of rapid rate pyrolysis in pulverized (44-53 microns) coal combustion. The specific mutagenic activity (i.e., the activity per unit sample weight) of extracts from particulates and volatiles captured on XAD-2 resin varied with coal type according to the order: subbituminous greater than high volatile bituminous greater than lignite greater than anthracite. Total mutagenic activity (the activity per gram of coal pyrolyzed), however, varied with coal type according to the order: high volatile bituminous much greater than subbituminous = lignite much greater than anthracite, due primarily to high organic yield during high volatile bituminous coal pyrolysis. Specific mutagenic activity peaked in a temperature range of 1300K to 1500K and generally appeared at higher temperatures and longer residence times than peak PAC production.

Coal↗