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Biomedical subjects

S Mishra

Publications and source records attributed to S Mishra.

At least 55 records · Page 3Linked to original sources
PubMed2001

Evaluation of inoculum addition to stimulate in situ bioremediation of oily-sludge-contaminated soil.

A full-scale study evaluating an inoculum addition to stimulate in situ bioremediation of oily-sludge-contaminated soil was conducted at an oil refinery where the indigenous population of hydrocarbon-degrading bacteria in the soil was very low (10(3) to 10(4) CFU/g of soil). A feasibility study was conducted prior to the full-scale bioremediation study. In this feasibility study, out of six treatments, the application of a bacterial consortium and nutrients resulted in maximum biodegradation of total petroleum hydrocarbon (TPH) in 120 days. Therefore, this treatment was selected for the full-scale study. In the full-scale study, plots A and B were treated with a bacterial consortium and nutrients, which resulted in 92.0 and 89.7% removal of TPH, respectively, in 1 year, compared to 14.0% removal of TPH in the control plot C. In plot A, the alkane fraction of TPH was reduced by 94.2%, the aromatic fraction of TPH was reduced by 91.9%, and NSO (nitrogen-, sulfur-, and oxygen-containing compound) and asphaltene fractions of TPH were reduced by 85.2% in 1 year. Similarly, in plot B the degradation of alkane, aromatic, and NSO plus asphaltene fractions of TPH was 95.1, 94.8, and 63.5%, respectively, in 345 days. However, in plot C, removal of alkane (17.3%), aromatic (12.9%), and NSO plus asphaltene (5.8%) fractions was much less. The population of introduced Acinetobacter baumannii strains in plots A and B was stable even after 1 year. Physical and chemical properties of the soil at the bioremediation site improved significantly in 1 year.

Acinetobacter↗
PubMed2001

Tramadol for postoperative shivering: a double-blind comparison with pethidine.

In most operating and recovery rooms, shivering is controlled by the use of humidifiers, warming blankets, and inhalation of humidified heated oxygen. However, pharmacological control is an effective alternate treatment modality. This randomized, double-blind trial, conducted in 30 ASA Grade 1 or 2 patients, was designed to explore the efficacy of tramadol and pethidine in the treatment of post-anaesthetic shivering. Tramadol is an inhibitor of the re-uptake of serotonin (5-hydroxytryptamine) and norepinephrine in the spinal cord. This facilitates 5-hydroxytryptamine release, which influences thermoregulatory control. We compared the efficacy of tramadol with that of pethidine, presently a widely used drug for the control of shivering. Patients received either tramadol 1 mg/kg or pethidine 0.5 mg/kg intravenously and the grade of shivering, pulse rate, blood pressure and respiratory rate were observed every 10 minutes after injection for one hour Shivering was significantly more likely to have ceased in the tramadol group (12 of 15 versus 4 of 15 cases, P<0.05) at 10 minutes after drug administration and this control was better sustained. No patients receiving tramadol had a recurrence of shivering. It is concluded that intravenous tramadol 1 mg/kg is more effective for the treatment of postoperative shivering than pethidine 0.5 mg/kg.

Adult↗
PubMed2001

Targeted disruption of luteinizing hormone/human chorionic gonadotropin receptor gene.

LH/hCG receptors were disrupted by gene targeting in embryonic stem cells. The disruption resulted in infertility in both sexes. The gonads contained no receptor mRNA or receptor protein. Serum LH levels were greatly elevated, and FSH levels were moderately elevated in both sexes; estradiol and progesterone levels decreased but were not totally suppressed in females; testosterone levels were dramatically decreased and estradiol levels moderately elevated in males. The external and internal genitalia were grossly underdeveloped in both sexes. Abnormalities included ambiguous vaginal opening, abdominal testes, micropenis, dramatically decreased weights of the gonads and reproductive tract, arrested follicular growth beyond antral stage, disarray of seminiferous tubules, diminished number and hypotrophy of Leydig cells, and spermatogenic arrest beyond the round spermatid stage. LH/hCG receptor gene disruption had no effect on FSH receptor mRNA levels in ovaries and testes, progesterone receptor (PR) levels in ovaries and androgen receptor (AR) levels in testes. However, it caused a dramatic decrease in StAR and estrogen receptor-alpha (ERalpha) mRNA levels and an increase in ERbeta mRNA levels in both ovaries and testes. Estradiol and progesterone replacement therapy in females and testosterone replacement in males, to determine whether phenotype and biochemical changes were a consequence of decreased gonadal steroid levels or due to a loss of LH signaling, revealed complete restoration of some and partial restoration of others. Nevertheless, the animals remained infertile. It is anticipated that the LH receptor knockout animals will increase our current understanding of gonadal and nongonadal actions of LH and hCG.

Animals↗
PubMed2001

Comparative two- and three-dimensional finite element modelling techniques for tibial fractures.

Often the choice of a two-dimensional modelling approach over a three-dimensional approach is made on the basis of available resources, and not on task appropriateness. In the case of simulating the mechanical behaviour of irregular anatomical structures in biomedical engineering, the authenticity of two-dimensional model behaviour and the interpretation of model solutions is of particular concern since little comparable two-dimensional and three-dimensional data have been published. As part of a research programme, a comparison was made between two-dimensional and three-dimensional finite element models (FEMs) that examine the stress-strain environment of a clinical bone fracture and callus. In comparison with the three-dimensional model, the two-dimensional model substantially underestimated peak compressive principal stresses in the callus tissue and peak equivalent strains. This was a consequence of geometrical and structural asymmetry in a plane perpendicular to the two-dimensional model. However, the two-dimensional model predicted similar patterns of stress and strain distribution to the corresponding mid-longitudinal plane of the three-dimensional model, and underestimates of peak stress and strain were much reduced. This confirmed that despite the irregular geometry and structure of the subject, the two-dimensional model provided a valid mechanical simulation in the plane of the fracture that it represented.

Biomechanical Phenomena↗
PubMed2001

Development of a novel plant system as biosensor for detecting environmental hazards and bioactive molecules through distinct responses.

Currently, chemicals are used excessively in medicine, industry, and agriculture throughout the world. Because of the current rise in environmental pollutants and hazardous exposures of human beings, there is an imperative need for monitoring the environment for biosafety. In addition, the importance of natural products with novel activity for drug or agrochemical scopes is being more and more realized. We report on a novel test system that can act as biosensors for detecting useful compounds while simultaneously monitoring or forecasting the biohazard exposure of organisms to chemicals as well as to physical factors in a given environment. Using different compounds and factors with known biological and cytotoxic activities, a detail plant test procedure has been developed that can be used in detecting and analyzing the value and/or danger of any given compound or treatment, including cell division inhibition, cytotoxicity, growth inhibition, and anticancer activities. The method provides a highly efficient single biosensor system that can replace several individual biotesting procedures. This plant assay procedure is a highly sensitive system for monitoring physical stress factors in the environment, including ionizing and nonionizing radiation. The procedure can be followed throughout the year because of the rapid growth rate of the plant used and its regeneration in ambient conditions. Therefore, the described system is highly useful to thoroughly monitor the environment and detection of new chemicals/compounds.

Biosensing Techniques↗
PubMed2000

Interactions between the cellular and humoral immune responses in Drosophila.

Drosophila has highly efficient defenses against infection. These include both cellular immune responses, such as the phagocytosis of invading microorganisms, and humoral immune responses, such as the secretion of antimicrobial peptides into the hemolymph [1] [2]. These defense systems are thought to interact, but the nature and extent of these interactions is not known. Here we describe a method for inhibiting phagocytosis in Drosophila blood cells (hemocytes) by injecting polystyrene beads into the body cavity. This treatment does not in itself make a fly susceptible to Escherichia coli infection. However, when performed on flies carrying the mutation immune deficiency (imd), which affects the humoral immune response [3], the treatment results in a striking decrease in resistance to infection. We therefore carried out a sensitized genetic screen to identify immunocompromised mutants by co-injecting beads and E. coli. From this screen, we identified a new gene we have named red shirt and identified the caspase Dredd as a regulator of the Drosophila immune response. The observation that mutants with defects in the humoral immune response are further immunocompromised by blocking phagocytosis, and thus inhibiting the cellular immune response, shows that the Drosophila cellular and humoral immune responses act in concert to fight infection.

Animals↗
PubMed2000

The influence of mechanical stimulus on the pattern of tissue differentiation in a long bone fracture--an FEM study.

2D, coronal plane, finite elements models (FEMs) were developed from orthogonal radiographs of a diaphyseal tibial fracture and its reparative tissue at four different time points during healing. Each callus was separated into regions of common tissue histology by computerised radiographic analysis. Starting point values of tissue material properties from the literature were refined by the model to simulate exactly the mechanical behaviour of the subject's callus and bone during loading. This was achieved by matching measured inter-fragmentary displacements with calculated inter-fragmentary forces. Stress and strain distributions in the callus and bone were calculated from peak inter-fragmentary displacements measured during natural walking activity, and were correlated with the subsequently observed pattern of tissue differentiation and maturation of the callus. The growth and stiffening of the external callus progressively reduced the inter-fragmentary gap strain. Partial maturation of the gap tissue was apparent only one week before fixator removal. Principal stresses in the callus were compared with 'yield stresses' in corresponding tissue from the literature. This indicated the presence of stress concentrations medial and lateral to the fracture gap, which probably caused tissue damage during normal activity levels. Tissue damage may also have precipitated partial structural failure of the callus, both of which were believed to have delayed healing during the middle third of the fixation period. Had the fixation device provided greater inter-fragmentary support during early healing, this may have prevented callus failure and the consequent delay in healing. A further benefit of this would have been the reduction of the initially high intra-gap tissue strains to a magnitude more conducive to earlier maturation of the bridging tissue that united the bone.

Adult↗
PubMed2000

Acute management of the performing voice.

Management of a singer's acute voice problem carries repercussions that may affect his or her career. When a vocalist develops a problem before a performance, the clinician is required to make a prompt diagnosis, determine the safety of the vocal performance, and provide treatment. The ability of the singer to fulfill the pending vocal performance is also of paramount importance. Therefore, it is important for the clinician to understand the presenting complaints, to evaluate the emergent vocal need of the singer, and to combine the art and science of laryngology to formulate the treatment plan.

Acute Disease↗
PubMed2000

Purification and characterization of polygalacturonase from banana fruit.

Polygalacturonase isoenzyme 3 (PG-3) was purified to homogeneity with a specific activity of 0.7 mu katal mg-1 protein from banana fruit pulp. The purified enzyme was a glycoprotein with ca. 8% carbohydrate. The molecular weight of the native enzyme was found to be 90 +/- 10 kDa with a subunit molecular weight of 29 +/- 2 kDa. The enzyme exhibited optimum activity at pH 4.3 and temperature 40 degrees C with activation energy 35.4 kJ mol-1. A unique property of the enzyme was the requirement of -SH groups for the enzyme activity. The enzyme was inhibited by p-CMB and activated by 2-ME and DTT. The inhibition of p-CMB could be reversed by DTT. The enzyme contained eight free -SH groups. The Km of the enzyme was 0.15% for polygalacturonic acid.

Carbohydrates↗
PubMed2000

24 hours prior to curtain.

A retrospective review was conducted of 40 singers presenting with acute voice problems prior to performance. The purpose of this study was to determine the reasons for seeking emergent voice treatment, the types of acute voice disorders, and the performance outcome. The patients were assessed by age, singing style, years of experience, chief complaint, laryngovideostroboscopic findings, and treatment regimens. The outcomes were classified as full, restricted, or no performance. The majority of patients were classical singers. Laryngovideostroboscopy frequently revealed a pattern of early glottic contact at the mid-portion of the membranous vocal fold in patients with acute laryngitis. Experienced singers uniformly sought treatment many days before their performance compared with inexperienced singers who presented closer in time to performance. Six patients initially withheld information, which had a bearing on their acute management. The results of this study suggest that there is a need to accurately diagnose and treat the singer's emergent problem and educate singers regarding early evaluation of medical problems. With modern evaluation techniques and multi-modality treatment, 85% of the singers proceeded to full performance without negative sequelae.

Acute Disease↗
PubMed2000

Response of chickens to infection with Newcastle disease virus isolated from a guinea fowl.

An isolate of Newcastle disease virus obtained from a guinea fowl was characterized as a viscerotropic velogenic strain based upon pathogenicity index studies. Following inoculation of the viral isolate oronasally into 3-week-old chickens, clinical signs appeared after an incubation period of 4-5 days and included dullness, depression, dyspnoea, diarrhoea and leg paralysis. The virus caused a mortality of 56% with haemorrhages at the tip of the glands of the proventriculus and caecal tonsil. Histopathological changes were prominent in the lymphoid organs, being characterized by depletion, degeneration and necrosis of the lymphoid tissues. The brain was the first organ affected, with changes being noticed 3 days after infection. Isolation of virus from various organs was more frequent from 5 to 10 days after infection, but the virus persisted in some of the organs until 21 days after infection. In spite of the high mortality, a good immune response was elicited by the isolate, as was evident from the antibody titre.

Animals↗
PubMed2000

Determination of iodide by derivatization to 4-iodo-N,N-dimethylaniline and gas chromatography-mass spectrometry.

A real-time determination of iodide is proposed which involves the oxidation of iodide with 2-iodosobenzoate in the presence of N,N-dimethylaniline. The reaction is completed within 1 min to yield 4-iodo-N,N-dimethylaniline, which is extracted in cyclohexane and determined by GC-MS. It was also possible to determine iodine by derivatization in the absence of 2-iodosobenzoate, and iodate by its reduction with ascorbic acid to iodide and subsequent derivatization. A rectilinear calibration graph was obtained for 0.02-50 micrograms l-1 iodide with a correlation coefficient of 0.9998. The limit of detection was 8 ng l-1 iodide. The method was applied to the determination of iodate in iodized table salt and free iodide and total iodine in sea-water, and to spiked samples when the recovery was in the range 96.8-104.3% (RSD 1.9-3.6%). A sample clean-up by solid-phase extraction with a LiChrolut EN cartridge is proposed.

Gas Chromatography-Mass Spectrometry↗
PubMed2000

Biphasic changes in nitric oxide generation in hemodialyzed patients with end-stage renal disease treated with recombinant human erythropoietin.

BACKGROUND: Use of recombinant human erythropoietin (rHuEpo) in patients with end-stage renal disease (ESRD) improves anemia and reduces the need for blood transfusions. However, one third of patients on rHuEpo develop hypertension, aggravation of preexistent hypertension, or other complications. Nitric oxide (NO) plays a role in blood pressure (BP) regulation. Whether rHuEpo treatment in ESRD is accompanied by alterations in NO production was explored in patients undergoing hemodialysis. METHODS: Of 121 consecutive patients in a hemodialysis clinic, 107 were treated with rHuEpo and 14 were untreated. Plasma was collected before and after hemodialysis for quantification of nitrite and nitrate (NOx). Findings were correlated with various routinely monitored parameters. RESULTS: Predialysis NOx levels were lower in the treated than the untreated group; postdialysis NOx levels were virtually the same. Thus, the change was less in the treated group. Urea reduction ratios (URR) and ultrafiltrate volumes were similar. The mean predialysis systolic BP was higher in the treated group than in the untreated group. The dose of rHuEpo did not correlate with the plasma NOx or the predialysis BPs. No correlation was found between NOx levels and Hb or gender. Of the 107 treated patients, 12 had an increased postdialysis NOx without differences in ultrafiltrate volumes or URR. This group had higher total serum calcium levels, faster pulses, and greater BP reductions than other treated patients. No difference was found in the use of calcium-channel blockers and serum phosphorus and intact parathyroid hormone concentrations did not differ significantly among these groups. CONCLUSIONS: Intermittently hemodialyzed ESRD patients treated with rHuEpo accumulate less NOx in the plasma before dialysis but generate more NOx during dialysis than untreated patients. About 11% of treated patients generated excessive amounts of NOx, thereby maintaining plasma concentrations at the predialysis level or higher. This group experienced significant hemodynamic consequences characteristic of the excessive action of NO.

Blood Pressure↗
PubMed1999

High-resolution holocene environmental changes in the thar desert, northwestern india

Sediments from Lunkaransar dry lake in northwestern India reveal regional water table and lake level fluctuations over decades to centuries during the Holocene that are attributed to changes in the southwestern Indian monsoon rains. The lake levels were very shallow and fluctuated often in the early Holocene and then rose abruptly around 6300 carbon-14 years before the present (14C yr B.P.). The lake completely desiccated around 4800 (14)C yr B.P. The end of this 1500-year wet period coincided with a period of intense dune destabilization. The major Harrapan-Indus civilization began and flourished in this region 1000 years after desiccation of the lake during arid climate and was not synchronous with the lacustral phase.

Journal Article↗
PubMed1999

Reduced sarcoplasmic reticulum Ca(2+)-uptake and expression of phospholamban in left ventricular myocardium of dogs with heart failure.

The purpose of this study was to examine the sarcoplasmic reticulum (SR) Ca(2+)-uptake and the expression of phospholamban (PLB) and Ca(2+)-ATPase (CAA) in left ventricular (LV) and right ventricular (RV) myocardium of 6 normal (NL) dogs and 6 dogs with chronic heart failure (HF). In addition, gene expression of PLB and CAA was also examined in LV myocardium of NL and HF dogs. HF (LV ejection fraction 23+/-2%) was produced by multiple sequential intracoronary microembolizations. Oxalate-dependent Ca(2+)-uptake was measured in isolated membrane vesicles. Using specific dog myocardial monoclonal antibody, the expression of CAA, PLB and calsequestrin (CSQ) were measured in sodium dodecyl sulfate extract prepared from LV and RV tissue. Steady-state mRNA levels were determined by Northern hybridization using specific cDNA clones of PLB, CAA, CSQ, and glyceraldehyde-3-phosphate dehydrogenase (GADPH), a house keeping gene. SR Ca(2+)-uptake of NL and HF dogs increased with increasing Ca(2+)concentrations and reached a plateau at 3 microm in both LV and RV. Total capacity (134+/-9 v 224+/-10 nmol(45)Ca/mg protein/10 min, P<0.05) and maximal velocity (15+/-2 v 2 nmol(45)Ca/mg protein/min, P<0.05) of the SR to sequester Ca(2+)was significantly lower in LV myocardium of HF dogs compared to NL, whereas the Hill coefficient and the affinity of the Ca(2+)-pump for Ca(2+)were unchanged. LV tissue levels of the PLB and CAA, normalized to noncollagen protein or to CSQ and the PLB and CAA mRNA levels, normalized to CSQ or GADPH mRNA, were also significantly lower in HF dogs compared to NL. In RV myocardial tissue, no significant differences in total capacity of SR to sequester Ca(2+), maximal velocity of SR Ca(2+)-uptake, the affinity and Hill Coefficient of the Ca(2+)-pump for Ca(2+), or tissue levels of PLB and CAA were observed between NL dogs compared to HF dogs. We conclude that SR Ca(2+)-uptake and SR PLB and CAA protein and gene expression levels are reduced in LV myocardium of dogs with chronic HF. These abnormalities can lead to Ca(2+)-overload and subsequent global LV dysfunction.

Animals↗