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Biomedical subjects

S Sen

Publications and source records attributed to S Sen.

At least 217 records · Page 12Linked to original sources

Vectorcardiographic monitoring to assess early vessel patency after reperfusion therapy for acute myocardial infarction.

Reperfusion therapy has lowered mortality in patients suffering from acute myocardial infarction. Failure to reperfuse is associated with an increased short- and long-term mortality. In a prospective study we used dynamic vectorcardiography to monitor 96 patients with acute myocardial infarction treated with reperfusion therapy to non-invasively assess coronary patency. The results from continuous monitoring were compared to those obtained from angiography. By using trend-analysis of QRS vector difference and ST vector magnitude, we were able to correctly identify 58 of the 70 patients (83%) with a reperfused infarct-related artery, and 19 of the 26 patients (73%) with a persistently occluded artery demonstrated at an early angiogram (diagnostic accuracy 80%). In patients with high-grade collateral flow to the infarct-related area, the results of the vectorcardiographic monitoring and of angiography showed the largest disagreement, whereas the accuracy of vectorcardiographic monitoring was high: 88% among patients without collaterals. The present results suggest that QRS complex and ST segment vectorcardiographic monitoring is a useful tool for assessing early coronary artery patency, and that dynamic vectorcardiography may help in identifying candidates for emergency coronary angiography.

Acute Disease↗

Sagittal contour restoration and canal clearance in burst fractures of the thoracolumbar junction (T12-L1): the efficacy of timing of the surgery.

The efficacy of timing of surgery (short segment fixation using transpedicular screws), in burst fractures of thoracolumbar spine was evaluated between May 1993 and October 1994. The patients were divided into two groups according to time elapsed between injury and operation. Cases operated on within the first 24 h were taken as the early surgery group (n = 10) and cases operated on later than 24 h after the injury were considered as the late surgery group (n = 8). The efficacy of treatment was assessed by evaluation of the sagittal index (SI) restoration and reduction of canal compromise. The pre- and postoperative values for SI and canal narrowing (CN) for both groups are as follows: Early preoperative SI-23.40 degrees, late preoperative SI-24.50 degrees, p = 0.53; early preoperative CN-0.47, late preoperative CN 0.52, p = 0.33; early postoperative SI-4.20 degrees, late postoperative SI-13.50 degrees, p = 0.0001; early postoperative CN-0.10, late postoperative CN-0.39, p = 0.0000. There is still controversy concerning the relationship between canal narrowing and neurologic deficit, and the effect, if any, of decompression on neural recovery. Nevertheless, if the main aim of the surgical procedure is to restore the SI and decompress the neural canal, then other alternatives of decompression and realignment should be preferred to indirect reduction using short segment transpedicular fixation in cases to be operated on later than 24 h after injury.

Adult↗

Safety of antitachycardia pacing in patients with implantable cardioverter defibrillators and severely depressed left ventricular function.

The purpose of this study was to investigate the efficacy and safety of antitachycardia pacing (ATP) in third-generation implantable cardioverter defibrillators (ICDs) for terminating spontaneously occurring ventricular tachycardias (VTs) in patients with severely depressed left ventricular (LV) function. Ninety-one patients with active ATP were followed for 16 +/- 13 months. During this period, 775 VT episodes occurring in 36 patients were treated by ATP. The patients were divided into two groups according to their LV ejection fraction (LVEF): group A with LVEF < or = 30% (n = 20), and group B with LVEF > 30% (n = 16). There were no differences between both groups in age, gender, underlying heart disease, indication for ICD therapy, or drug therapy. The VT rates were comparable (group A: 183 +/- 16 beats/min; group B: 180 +/- 21 beats/min; P = NS). Eighty-three percent of all episodes (n = 332) in group A and 93% of the VTs (n = 443) in group B were ATP terminated (P < 0.01). Ten percent of VTs in group A were accelerated by ATP into the ventricular fibrillation zone versus 2% in group B (P < 0.01). The individual termination rate and acceleration rate per patient were comparable in both groups. All VT episodes unresponsive to ATP were converted by backup shocks. The efficacy of first-shock therapy was similar in both groups (group A: 89%; group B: 97%; P = NS). The proportion of patients who needed at least one backup shock for unsuccessful ATP was comparable in both groups (group A: 65%; group B: 56%; P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Defibrillators, Implantable↗

Quantification of myotrophin from spontaneously hypertensive and normal rat hearts.

A novel peptide, myotrophin, has been isolated, purified, cloned, and sequenced from the hearts of spontaneously hypertensive rats (SHR) and from dilated cardiomyopathic human heart tissue. Myotrophin accelerates myocyte growth by stimulating protein synthesis (not by altering myocardial cell division). Our successive studies were conducted to evaluate the pathophysiological significance of myotrophin; a solid-phase radioimmunoassay technique was developed for quantifying the protein in hypertrophied and normal hearts. Specific antipeptide antibody was raised in rabbits against a peptide that represents a selected amino acid sequence of a 17-amino acid myotrophin segment by using the multiple antigenic peptide technique. The specificity of the antibody was evaluated by determining the affinity constant after constructing the Scatchard plot obtained from the ratio of bound to free myotrophin against bound myotrophin. The value obtained was 2.61 x 10(7) L/mol. The specificity was further demonstrated by Western blot analysis, in which a single protein band was obtained in the region of 12 kD. Pretreatment of the antibody with myotrophin completely blocked the binding sites, because no protein band was detected on the immunoblot. The antibody prevented the myocardial protein synthesis induced by myotrophin as revealed by the blockage of the stimulation of [3H]leucine incorporation into myocyte protein. Quantification of myotrophin from different heart tissues was achieved by Western blot and dot blot analyses. Amounts of myotrophin present in different dots were determined by using a video image analyzer. The level of myotrophin in the embryonic tissue was found to be similar in male normal and SHR hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

Securitizing receivables offers low-cost financing option.

Securitization began in the 1980s with mortgage payments, auto loans, and credit card debt being pooled and used as collateral for securities offerings. More recently, healthcare providers have securitized accounts receivables to obtain low-cost, off-balance-sheet financing. As the need to both raise capital and contain costs grows in health care, providers likely will make increased use of this financing method.

Accounts Payable and Receivable↗

Molecular dynamics simulations of excimer forming (+)-anti-BPDE-DNA adducts in aqueous solution.

The chemical carcinogen (+)-anti BPDE preferentially binds covalently to the guanine base in the minor groove of DNA. Fluorescence spectroscopic studies have shown that the BPDE molecules bound to DNA can interact in their photo-excited state giving strong excimer fluorescence when bound to poly(dGdC).poly(dGdC). It was suggested that the formation of such excited state complexes is most probable when the two (+)-anti-BPDE bind to guanines of adjacent base pairs on the two different strands of the DNA. In the present work a model for such an excimer forming DNA-BPDE double adduct system has been constructed and shown to be stable over a 300 ps molecular dynamics simulation in a water box. The model is a d(CG)3.d(CG)3 molecule with two BPDE molecules bound to the guanines at the 4th position on each strand, located in the minor groove and each oriented towards the 5' end of the modified strand, respectively. The results of 300 ps MD simulation show that the two BPDE chromophores exhibited on the average a relative geometry favourable for excimer formation. The local structure at the adduct position was considerably distorted and the helix axis was bent. The modified bases were found to be paired through a stable single non-Watson Crick type of hydrogen bond.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

Anti-stress activity of N-phthaloyl gamma-aminobutyric acid in rats.

The effect of immobilization restraint stress (RS) on some biochemical and biophysical parameters in rats and their modulation by N-phthaloyl gamma-aminobutyric acid (P.GABA) was studied. RS did not affect the levels of serum Ca2+, inorganic phosphate, bilirubin, total protein, but caused insignificant increase of albumin level and significantly decreased the cholesterol level. This RS induced decrease of serum cholesterol level was reversed by prior treatment with P.GABA, while the albumin content showed a decrease. RS-induced a generalised increase in serum enzyme activity of lactate dehydrogenase (LDH), alkaline phsophatase (AIP), serum glutamate pyruvate transaminase (SGPT) and serum glutamate-oxaloacetate transaminase (SGOT). P.GABA normalised RS-induced increase of LDH and AlP activity, but it further enhanced SGOT and SGPT activities. In synaptosomal membranes, RS caused a decrease in clusterization and fluidity, but the thickness of the membrane increased as studied by fluorescence probes. Prior administration of P.GABA normalised the changes observed in the synaptic membrane.

Animals↗

Properties of mitochondrial DNA polymerase in mitochondrial DNA synthesis in yeast.

Mitochondrial DNA polymerase from Saccharomyces cerevisiae, purified 3500 fold, was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into three polypeptides. The major 150 kDa polypeptide was probably the catalytic subunit of the mitochondrial (mt) DNA polymerase and the other two polypeptides could be either proteolytic cleavage products of the polymerase, other subunits of the enzyme or protein contaminants. The mtDNA polymerase preferred an A+T-rich DNA template and did not require any RNA primer for DNA synthesis, at least under in vitro reaction conditions. It showed higher processivity on a double-stranded linear DNA template than on a single-stranded circular DNA template, and was capable of synthesizing at least about 1200 nucleotide primer-extended products without any major pause on a double-stranded DNA template.

Base Sequence↗

Transmission of Sarcoptes scabiei from animal to man and its control.

Outbreak of Sarcoptes scabiei in animals spilling over to man in close association was observed in two adjacent villages, Fewgram and Nurpur in the district of Birbhum, West Bengal, from mid-November to mid-December, 1991. Nineteen goats and one calf who did not receive any treatment died of sarcoptic manage. All infected animals got cured with external application of deltamethrin, a synthetic pyrethroid and triazapentadiene. Human cases were treated successfully with benzene hexachloride (2%).

Adult↗

Myasthenia gravis.

Explore the source record for details and available documents.

Autoantibodies↗

Breast lumps: a study of 10 years.

A retrospective study of lumps in the breast sent for histopathological examination in Calcutta National Medical College for a period of last 10 years was done. It was found that 2062 cases (6.82%) of histopathological examination of breast lump were studied out of a total 30208 specimens during that period. There were 1528 cases from benign breast lesions and 504 cases from the malignant breast lesions. The most common lesion found histologically was fibro-adenoma in 950 cases. Others included 150 cases of inflammatory breast diseases of which 36 cases were diagnosed as tuberculosis, 386 cases as fibrocystic disease and 42 cases as other benign neoplastic diseases. Out of 504 malignant cases 456 had carcinoma and 48 had sarcoma. Only 30 cases of male breast lesions were sent of which only a single case of infiltrating duct carcinoma was found, 28 cases had gynaecomastia and one case showed the evidence of fibrocystic disease.

Adolescent↗