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Biomedical subjects

S Kumar

Publications and source records attributed to S Kumar.

At least 1,243 records · Page 69Linked to original sources
PubMed1995

Postural aberrations in low back pain.

The purpose of this study was to measure and describe postural aberrations in chronic and acute low back pain in search of predictors of low back pain. The sample included 59 subjects recruited to the following three groups: chronic, acute, or no low back pain. Diagnoses included disc disease, mechanical back pain, and osteoarthritis. Lumbar lordosis, thoracic kyphosis, head position, shoulder position, shoulder height, pelvic tilt, and leg length were measured using a photographic technique. In standing, chronic pain patients exhibited an increased lumbar lordosis compared with controls (p < .05). Acute patients had an increased thoracic kyphosis and a forward head position compared with controls (p < .05). In sitting, acute patients had an increased thoracic kyphosis compared with controls (p < .05). These postural parameters identified discrete postural profiles but had moderate value as predictors of low back pain. Therefore other unidentified factors are also important in the prediction of low back pain.

Acute Disease↗
PubMed1995

Success and yield of second attempt ERCP.

Endoscopic retrograde cholangiopancreatography (ERCP) has been shown to be an accurate and reliable method to evaluate biliary and pancreatic disorders. When an attempt to perform ERCP fails, the managing physician must decide whether to repeat the procedure or rely on other alternatives. We tallied the data from 113 patients referred to our institution for repeat ERCP after a failed attempt at another hospital. This group represented approximately 5% of the total population studied during that period of time. All of the patients had undergone one or more unsuccessful ERCP(s) and were referred to our center for another attempt at ERCP. Using a variety of techniques, we were successful in cannulating the desired duct in 96% of attempts. Pathologic findings were present in 64% of cases, of which 22% were sphincter of Oddi dysfunction. Thus, second attempt ERCP is generally worthwhile if clinically indicated and ERCP expertise is geographically available.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1995

Structure determination and analysis of local bending in an A-tract DNA duplex: comparison of results from crystallography, nuclear magnetic resonance, and molecular dynamics simulation on d(CGCAAAAATGCG).

We have presented a detailed analysis for structure determinations for the DNA duplex d(CGCAAAAATGCG) obtained from X-ray crystallography, nuclear magnetic resonance, and molecular dynamics simulation. Each of the structures for the duplex deviates from the structure of the canonical form of B-DNA in a number of observable characteristics. Specifically, the three determinations all contain DNA axis deflections at the junctions of the A-tract with the flanking sequences. The analysis provided shows that the general characteristics of the structures obtained for d(CGCAAAAATGCG) from X-ray, NMR, and MD methods turn out to be quite similar. The extent to which this result can be generalized remains to be established by consideration of similar cross-comparisons on diverse oligonucleotide structures.

Base Sequence↗
PubMed1995

ICE-like proteases in apoptosis.

The discovery of structural and functional similarities between the product of the nematode cell-death gene ced-3 and mammalian interleukin-1 beta-converting enzyme (ICE) is providing important insights into the molecular mechanism of apoptosis. This article summarizes the current knowledge of ICE and its homologues, and how these may be involved in regulating apoptosis.

Amino Acid Sequence↗
PubMed1995

Electromyography of spinal and abdominal muscles during garden raking with two rakes and rake handles.

Fifteen young normal subjects (4 males, 11 females) participated in the study. They were required to assume a staggered upright posture with left leg leading in front of a 75 x 75 cm raking box with 20-cm deep evenly distributed dry and wet sand and dirt. The subjects raked using a pulling and pushing action and a 60 cm stroke length at a self-selected optimum pace with a normal straight handled rake and with a rake with a modified handle. The handle modification consisted of three curvatures of 50, 60 and 50 degrees, with an effective rake length of 150 cm. While the subjects performed the raking their EMG was recorded from erectores spinae at L1 and L3 levels, external obliques and rectus abdominis bilaterally. The pulling activities with both rakes generated significantly different EMGs from pushing (p < 0.01). The normal rake generated marginally higher activity compared to the modified rake. However, in pushing the modified rake generated much higher EMG activity than the normal rake (p < 0.01). The medium being raked and the moisture in it also had a significant effect on EMG (p < 0.02). On the basis of the results of this study, the normal rake was concluded to be a better rake.

Abdominal Muscles↗
PubMed1995

Stereoselective metabolism of dibenz[a,h]acridine to bay-region diol epoxides by rat liver microsomes.

The carcinogen dibenz[a,h]acridine (DB[a,h]ACR is metabolized predominantly to trans-3,4-dihydroxy-3,4-dihydro-dibenz[a,h]acridine (DB[a,h]ACR-3,4-diol) and the proximate carcinogen trans-10,11-dihydroxy-10,11-dihydrodibenz[a,h]acridine (DB[a,h]ACR-10,11-diol) [Steward et al. (1987) Carcinogenesis, 8, 1043-1050]. In the present investigation, the stereoselectivity of rat liver enzymes in metabolism of DB[a,h]ACR to its 3,4-diol and 10,11-diol and of DB[a,h]ACR-10,11-diol enantiomers to their bay-region diol epoxides has been examined with liver microsomes from control and 3-methylcholanthrene-treated rats. Both microsomal preparations produced the major metabolites DB[a,h]ACR-3,4-diol and DB[a,h]ACR-10,11-diol containing predominantly R,R-enantiomers with 38-54% optical purity. Metabolism of (-)-(10R,11R)- and (+)-(10S,11S)-enantiomers of DB[a,h]ACR-10,11-diol by liver microsomes from control rats produced predominantly bay-region diol epoxides (46-59% of total metabolites), whereas very little bay-region diol epoxides (14-17% of total metabolites) were produced by liver microsomes from 3-methylcholanthrene-treated rats. The bay-region diol epoxides produced in these studies consisted of predominantly DB[a,h]ACR-10,11-trans-diol epoxide diastereomer in which the benzylic hydroxyl group and epoxide oxygen are trans. However, (-)-DB[a,h]ACR-10R,11R-diol, a major metabolite of DB[a,h]ACR, was metabolized by liver microsomes from 3-methylcholanthrene-treated rats to (+)-[8R,9S,10S,11R]-DB[a,h]ACR-10,11-trans-diol epoxide, a diastereomer which displayed high mutagenic activity in V79 cells, in an amount which was 6.5-fold greater than that of the corresponding cis-diol epoxide diastereomer. The relative amounts of trans-diol epoxide versus cis-diol epoxide in the mixture of bay-region diol epoxides produced from DB[a,h]ACR-10R,11R-diol and DB[a,h]ACR-10S,11R-diol with liver microsomes from control rats and from DB[a,h]ACR-10S,11S-diol with liver microsomes from 3-methylcholanthrene-treated rats were 1.7, 2.1 and 2.3 respectively.

Acridines↗
PubMed1995

A new method of inference of ancestral nucleotide and amino acid sequences.

A statistical method was developed for reconstructing the nucleotide or amino acid sequences of extinct ancestors, given the phylogeny and sequences of the extant species. A model of nucleotide or amino acid substitution was employed to analyze data of the present-day sequences, and maximum likelihood estimates of parameters such as branch lengths were used to compare the posterior probabilities of assignments of character states (nucleotides or amino acids) to interior nodes of the tree; the assignment having the highest probability was the best reconstruction at the site. The lysozyme c sequences of six mammals were analyzed by using the likelihood and parsimony methods. The new likelihood-based method was found to be superior to the parsimony method. The probability that the amino acids for all interior nodes at a site reconstructed by the new method are correct was calculated to be 0.91, 0.86, and 0.73 for all, variable, and parsimony-informative sites, respectively, whereas the corresponding probabilities for the parsimony method were 0.84, 0.76, and 0.51, respectively. The probability that an amino acid in an ancestral sequence is correctly reconstructed by the likelihood analysis ranged from 91.3 to 98.7% for the four ancestral sequences.

Amino Acid Sequence↗
PubMed1995

A human recessive neurosensory nonsyndromic hearing impairment locus is potential homologue of murine deafness (dn) locus.

A locus for recessive neurosensory nonsyndromic hearing impairment maps to chromosome 9q13-q21 in two regionally separate consanguineous families from India. Each family demonstrates a LOD score greater than 4.5 to this region. D9S15, tightly linked to the Friedreich's ataxia locus, a region that has been defined with over 1 Mb of YAC contig information and several expressed sequences, is one of the flanking markers. In mice, the deafness (dn) locus maps to mouse chromosome 19 and flanking loci are syntenic to human chromosome 9q11-q21. The dn mouse is a potential model for the hearing impairment found in both these families.

Chromosome Mapping↗
PubMed1995

Mutation of the glucagon receptor gene and diabetes mellitus in the UK: association or founder effect?

Recent evidence suggests that a mutation of the glucagon receptor (GCG-R) gene is involved in the development of type 2 diabetes in French patients. We have examined patients from three geographically distinct regions in the UK and found the GGT40 (Gly) to AGT40 (Ser) mutation to be present in 15/691 (2.2%) of patients with type 2 (non-insulin dependent) diabetes and 1/425 (0.2%) of geographically matched controls and have therefore replicated association of the GCG-R mutation with classical type 2 diabetes (Fisher's exact test p = 0.008). An increased frequency of the mutation of the GCG-R gene was also found in probands of type 1 (insulin dependent) diabetic multiplex (affected sib pair) families, (10/404, 2.5%). However, a lack of preferential transmission from parents heterozygous for the mutation, to affected type 1 diabetic sibs may suggest population stratification. This in turn cannot be excluded as an alternative explanation for the difference in frequency of the GCG-R gene mutation between subjects with type 2 diabetes and normal controls.

Diabetes Mellitus, Type 1↗
PubMed1995

Four-cluster analysis: a simple method to test phylogenetic hypotheses.

A simple statistical test for comparing three alternative phylogenetic hypotheses for four monophyletic groups is presented. This test is based on the minimum-evolution principle, and it does not require any information regarding the branching order within each monophyletic group. It is computationally efficient and can be easily extended to five or more monophyletic groups.

Animals↗
PubMed1995

18S rRNA data indicate that Aschelminthes are polyphyletic in origin and consist of at least three distinct clades.

The Aschelminthes is a collection of at least eight animal phyla, historically grouped together because the absence of a true body cavity was perceived as a pseudocoelom. Analyses of 18S rRNA sequences from six Aschelminth phyla (including four previously unpublished sequences) support polyphyly for the Aschelminthes. At least three distinct groups of Aschelminthes were detected: the Priapulida among the protostomes, the Rotifera-Acanthocephala as a sister group to the protostomes, and the Nematoda as a basal group to the triploblastic Eumetazoa.

Acanthocephala↗
PubMed1995

Use of a spinal model to quantify the forces and motion that occur during therapists' tests of spinal motion.

BACKGROUND AND PURPOSE: Despite the widespread use of spinal mobilization, little is known about the forces used or the accuracy of therapists in estimating the forces they use in administering the technique. The purposes of this study were to quantify the forces used and to determine the accuracy of therapists in applying forces on a mechanical model. SUBJECTS: Ten physical therapists participated. METHODS: A spinal model was used to measure applied force and displacement under different conditions of stiffness. The therapists applied oscillatory posteroanterior mobilizations to the model under three different conditions of stiffness. RESULTS: Mean peak forces across grades and stiffness levels ranged between 57.59 and 178.27 N. The forces were generally lower in the least stiff condition. Displacement varied with stiffness and mobilization grade. In the least stiff condition, the mean displacement varied between 2.25 and 3.45 mm for grades 1 to 4, respectively. CONCLUSION AND DISCUSSION: Inter-therapist variability was high, and there was a systematic bias in underestimating the magnitude of applied force and in overestimating motion. The variability in force application and the general overestimation of motion detection may explain the poor reliability of measurements obtained with clinical tests based on motion palpation.

Adult↗
PubMed1995

Renal thrombotic microangiopathy associated with multicentric Castleman's disease. Report of two cases.

Castleman's disease (also called giant lymph node hyperplasia or angiofollicular lymph node hyperplasia) is a clinicopathological entity of unknown etiology. Two histologic patterns of lymph nodes are classically recognized: the hyaline-vascular and plasma-cell variants. Recently, multicentric Castleman's disease has emerged as a separate clinical entity manifested primarily by generalized lymphadenopathy and systemic manifestations, such as thrombocytopenia, hemolytic anemia, hepatosplenomegaly, altered liver function tests, central nervous system alterations, and autoimmune manifestations. A number of renal alterations have been described in association with the two pathological variants of Castleman's disease, but thrombotic microangiopathy has been previously reported only once in a patient with Castleman's disease. No renal biopsy was performed in that patient, although there was evidence of renal dysfunction. We report two cases of biopsy-proven renal thrombotic microangiopathy associated with multicentric Castleman's disease. In addition to having lymph node pathology characteristic of Castleman's disease, both patients presented with generalized lymphadenopathy and systemic manifestations, including acute renal failure, hypergammaglobulinemia, anemia, thrombocytopenia, and hypoalbuminemia. Autoantibodies were present in both patients, including antiphospholipid antibodies in one patient. The renal biopsies, examined by light, immunofluorescence, and electron microscopy, were diagnostic for renal thrombotic microangiopathy. The simultaneous development of two rather uncommon syndromes, multicentric Castleman's disease and renal thrombotic microangiopathy, suggests a possible link between Castleman's disease and renal thrombotic microangiopathy. Furthermore, we propose that the production of autoantibodies, in particular antiphospholipid antibodies, may lead to the development of thrombotic microangiopathy in some patients with multicentric Castleman's disease.

Adult↗
PubMed1995

In vivo axial rotations and neutral zones of the thoracolumbar spine.

Fourteen normal male subjects with mean age 23 (range 20-32) years and mean body weight of 69.6 kg underwent right and left axial rotation in a special machine--axial rotation tester (AROT). The AROT was designed and fabricated such as to allow uninhibited coupled axial rotation and lateral flexion while preventing flexion and extension. The range of rotation (ROR) and neutral zone (NZ) were recorded during active rotation (.A), active rotation with blindfold (.B), and passive rotation with blindfold (.P). Finally, bilateral axial rotation was tested with 6, 12, 18, 24, 30, and 36 Nm rotary torque (.T). There was no significant difference between ROR.A and ROR.B, both being approximately 140 degrees. However, there was a significant difference between NZ.A and NZ.B (p < 0.01). ROR.P was approximately 30 degrees greater than ROR.A. The trunk structures showed a nonlinear viscoelastic behavior with progressive rotary torque application. The neutral zone in axial rotation did not show significant difference between different loads. It is reported that the rotary neutral zone varies between subjects, and it is suggested to be contributory to spinal laxity.

Adult↗
PubMed1995

Surgical treatment of complete acromioclavicular dislocation using the coracoacromial ligament and coracoclavicular fixation: report of a technique in 14 patients.

Fourteen cases of a complete dislocation of the acromioclavicular joint were treated using a modified technique of surgical repair involving the transfer of the coracoacromial ligament to reconstruct the coracoclavicular ligaments and coracoclavicular fixation with a screw. In addition, the lateral 2 cm of the clavicle was removed and the coracoacromial ligament attached to the raw surface. Eleven patients underwent surgery < 2 weeks after injury, whereas three underwent surgery 6 months after the initial episode. Follow-up of 2-4 years showed excellent results in 12 and good in two cases. It is our recommendation that coracoclavicular ligament reconstruction should be supplemented with clavicular fixation to the coracoid to ensure acromioclavicular alignment.

Acromioclavicular Joint↗