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Biomedical subjects

N A Shah

Publications and source records attributed to N A Shah.

At least 19 recordsLinked to original sources
PubMed2005

Operative management of acetabular fractures. A review of 73 fractures.

Between June 1994 and December 2000, 80 displaced acetabular fractures were treated by open reduction and internal fixation, where possible by a single surgical approach. We report our results in 72 patients (73 fractures) who completed a minimum follow-up of 2 years. The average age of patients was 39.5 years (range 15-76 years). Thirty-four fractures were classified as simple and the remaining 39 were complex fractures. Twenty-four patients were recorded to have posterior dislocation of the hip joint at the time of initial presentation and at surgery eight patients were noted to have varying degrees of damage to the head of the femur. The average time to surgery was 11.7 days (range 1-35 days); 80% of cases were operated within 2 weeks period. The average follow-up was 45.5 months (range 24-96 months). In 67 fractures (92%), only a single approach was used (Anterior Ilioinguinal 26 cases; Posterior Kocker-Lagenbach 41 cases). Five fractures needed an extensile triradiate approach and only one case required a combined anterior and posterior approach. Congruent reduction was achieved in 89% of cases. Main complications included deep infection in two patients (2.7%) and severe degenerative changes in three patients (4.2%). A total of four patients (5.5%) required a total hip replacement. There were no cases of deep vein thrombosis or pulmonary embolism. Heterotopic ossification grade III was seen in three (4.1%) cases and none were grade IV. At the latest follow-up the average Harris hip score was 85 (range 20-100). We conclude that in the majority of cases internal fixation is possible through a single approach provided patients are referred early to a specialist unit. This results in satisfactory outcome with reduced morbidity and complication rate.

Acetabulum↗
PubMed2004

Cellular automata and its advances to drug therapy for HIV infection.

This paper gives an over view of the use of cellular automata (CA) model of drug therapy for HIV infection. Nonuniform CA is employed to simulate drug treatment of HIV infection, where each computational domain may contain different CA rules, in contrast to normal uniform CA models. Ordinary (or partial) differential equation models are insufficient to describe the two extreme time scales involved in HIV infection (days and decades), as well as the implicit spatial heterogeneity. Zorzenon and Coutinho [Phy Rev Lett, 16 (2001) 1] reported a cellular automata approach to simulate three-phase patterns of human immunodeficiency virus (HIV) infection consisting of primary response, clinical latency and onset of acquired immunodeficiency syndrome (AIDS). But here we present a related model, based on non-uniform CA to study the dynamics of drug therapy of HIV infection. The main aim in this model is to simulate the four phases (acute, chronic, drug treatment responds and onset of AIDS). The results shown here indicate that both simulations (with and without treatments) evolve to the relatively same steady state (characteristics of Wolfram's class II behavior). Different kinds of drug therapies can also be simulated in this model, which can be found useful for developing a proper drug therapy.

Anti-HIV Agents↗
PubMed2001

Identification of a mammalian long chain fatty acyl elongase regulated by sterol regulatory element-binding proteins.

Fatty acids are synthesized de novo from acetyl-CoA and malonyl-CoA through a series of reactions mediated by acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). In rodents, the principal fatty acid produced by FAS is palmitic acid (16:0). Sterol regulatory element-binding proteins (SREBPs) enhance the transcription of many genes responsible for fatty acid synthesis. In transgenic mice that overexpress SREBPs in liver, the rate of fatty acid synthesis is markedly increased, owing to the activation of these biosynthetic genes, which include ATP citrate lyase, ACC, FAS, and stearoyl-CoA desaturase. The fatty acids that accumulate in livers of SREBP transgenic mice are 18 carbons rather than 16 carbons in length, suggesting that the enzymes required for the elongation of palmitic to stearic acid may be induced. Here, we report the cDNA cloning of a murine long chain fatty acyl elongase (LCE) that was identified initially by oligonucleotide array analysis of mRNA from SREBP transgenic mouse livers. LCE mRNA is highly expressed in liver and adipose tissue. The cDNA encodes a protein of 267 amino acids that shares sequence identity with previously identified very long chain fatty acid elongases. Cells that overexpress LCE show enhanced addition of 2-carbon units to C12-C16 fatty acids. We provide evidence that LCE catalyzes the rate-limiting condensing step in this reaction. The current studies suggest that mouse LCE expression is increased by SREBPs and that the enzyme is a component of the elusive mammalian elongation system that converts palmitic to stearic acid.

Acetyltransferases↗
PubMed2001

High-throughput variation detection and genotyping using microarrays.

The genetic dissection of complex traits may ultimately require a large number of SNPs to be genotyped in multiple individuals who exhibit phenotypic variation in a trait of interest. Microarray technology can enable rapid genotyping of variation specific to study samples. To facilitate their use, we have developed an automated statistical method (ABACUS) to analyze microarray hybridization data and applied this method to Affymetrix Variation Detection Arrays (VDAs). ABACUS provides a quality score to individual genotypes, allowing investigators to focus their attention on sites that give accurate information. We have applied ABACUS to an experiment encompassing 32 autosomal and eight X-linked genomic regions, each consisting of approximately 50 kb of unique sequence spanning a 100-kb region, in 40 humans. At sufficiently high-quality scores, we are able to read approximately 80% of all sites. To assess the accuracy of SNP detection, 108 of 108 SNPs have been experimentally confirmed; an additional 371 SNPs have been confirmed electronically. To access the accuracy of diploid genotypes at segregating autosomal sites, we confirmed 1515 of 1515 homozygous calls, and 420 of 423 (99.29%) heterozygotes. In replicate experiments, consisting of independent amplification of identical samples followed by hybridization to distinct microarrays of the same design, genotyping is highly repeatable. In an autosomal replicate experiment, 813,295 of 813,295 genotypes are called identically (including 351 heterozygotes); at an X-linked locus in males (haploid), 841,236 of 841,236 sites are called identically.

Algorithms↗
PubMed2001

The Lubinus patellofemoral arthroplasty. A five- to ten-year prospective study.

We present a prospective review of the outcome of 76 Lubinus patellofemoral arthroplasties carried out in 59 patients between 1989 and 1995. At a mean follow-up of 7.5 years, 62 knees in the 48 patients were reviewed; 11 patients (14 knees) had died. None was lost to follow-up. The clinical outcome using the Bristol Knee Scoring system was satisfactory in 45% of the cases. Maltracking of the patella, resulting in lateral tilt, subluxation and polyethylene wear, was the most common complication (32%). Revision surgery was carried out in 21 knees (28%) giving a cumulative survival rate of 65% (confidence interval (CI) 49 to 77) at eight years. The survival rate for revision and moderate pain was 48% (CI 36 to 59) at six years. Progression of arthritis was seen in seven cases (9%). In five of these (6.5%), the symptoms were severe enough to need revision surgery. Due to the high proportion of unsatisfactory results, we have discontinued the use of this prosthesis.

Aged↗
PubMed1998

Copper, zinc, and magnesium levels in non-insulin dependent diabetes mellitus.

A relationship has been reported between trace elements and diabetes mellitus. This study evaluated the role of such a relationship in 83 patients with non-insulin dependent diabetes mellitus (40 men and 43 women), with a mean duration of diabetes of 3.9 +/- 3.6 years. Patients with nephropathy were excluded. Thirty healthy non-diabetic subjects were studied for comparative analysis. Subjects were subdivided into obese and non-obese. Diabetic subjects were also subdivided into controlled and uncontrolled groups; control was based on fasting blood glucose and serum fructosamine levels. Plasma copper, zinc and magnesium levels were analysed using a GBC 902 double beam atomic absorption spectrophotometer. Plasma zinc and magnesium levels were comparable between diabetic and non-diabetic subjects, while copper levels were significantly elevated (p < 0.01) in diabetic patients. Age, sex, duration and control of diabetes did not influence copper, zinc, or magnesium concentrations. We conclude that zinc and magnesium levels are not altered in diabetes mellitus, but the increased copper levels found in diabetics in our study may merit further investigation of the relationship between copper and non-insulin dependent diabetes mellitus.

Adult↗
PubMed1998

Unicompartmental or total knee replacement? Five-year results of a prospective, randomised trial of 102 osteoarthritic knees with unicompartmental arthritis.

We randomised 102 knees suitable for a unicompartmental replacement to receive either a unicompartmental (UKR) or total knee replacement (TKR) after arthrotomy. Both groups were well matched with a predominance of females and a mean age of 69 years. Patients in the UKR group showed less perioperative morbidity, but regained knee movement more rapidly and were discharged from hospital sooner. At five years, two UKRs and one TKR had been revised; another TKR was radiologically loose. All other knees appeared to be clinically and radiologically sound. Pain relief was good in both groups but the number of knees able to flex > or =120 degrees was significantly higher in the UKR group (p < 0.001) and there were more excellent results in this group. Our findings have shown that UKR gives better results than TKR and that this superiority is maintained for at least five years.

Aged↗
PubMed1997

Diet and lifestyle guidelines and desirable levels of risk factors for the prevention of diabetes and its vascular complications in Indians: a scientific statement of The International College of Nutrition. Indian Consensus Group for the Prevention of Diabetes.

BACKGROUND: There has been a rapid increase in the prevalence of diabetes and cardiovascular disease in India, in association with rapid changes in diet and lifestyle. In adults, the prevalence of diabetes, hypertension and coronary artery disease is two- to threefold greater in the urban population than in rural populations; it is associated with modest insulin resistance in urban groups. METHODS: In response to a proposal by the International College of Nutrition that specialist experts should develop consensus recommendations for the prevention of chronic diseases, Indian specialists in diabetes and vascular disease have collaborated to produce guidelines relevant to the population of India. RECOMMENDATIONS: Because Indian urban populations have a modest increase in overweight and low rates of obesity in association with the rapid emergence of diabetes and cardiovascular risk, a body mass index of 21 kg/m2 should be considered safe, with a range of 19-23 kg/m2 acceptable; > 23 kg/m2 should be considered overweight, and > 25 kg/m2 should be taken to indicate obesity. A waist:hip ratio > 0.88 in males and > 0.85 in females should be considered to indicate central obesity, because the prevalence of coronary disease, hypertension and associated disturbances of insulin resistance are more common above these limits. For the prevention of vascular disease, there is general international consensus that the desirable serum concentration of cholesterol should be < 170 mg/dl (> 4.42 mmol/l), which may also be optimal for Indians; values between 170 and 200 mg/dl (4.42-5.2 mmol/l) should be considered borderline. The critical values for low density lipoprotein cholesterol may be < 90 mg/dl (ideal), 90-110 mg/dl (borderline high) and > 110 mg/dl (high) (< 2.32, 2.32-2.84 and > 2.84 mmol/l, respectively). Fasting triglycerides should be < 150 mg/dl (< 1.69 mmol/l) and high-density lipoprotein cholesterol > 35 mg/dl (> 0.9 mmol/l). The limit for the total energy derived from fat intake should be < 21%/day (7% each for saturated, polyunsaturated and mono-unsaturated fatty acids). The carbohydrate intake should provide more than 65% of daily energy, mainly from complex carbohydrates. A daily dietary intake of 400 g fruits, vegetables and legumes, 400 g cereals, in conjunction with 25 g soya bean or mustard or canola oils (rich in n-3 fatty acids) in place of fats rich in saturated fat, may be protective against diabetes and vascular disease. Moderate physical activity with the aim of burning 300 Kcal/day (> 1255 KJ/day), and cessation of tobacco and alcohol consumption, may provide an effective programme for prevention of diabetes and its vascular complications in Indians.

Adult↗
PubMed1992

Results of pars plana vitrectomy in 62 cases of vitreous haemorrhage.

62 Cases with unresolving Vitreous Haemorrhage due to varied etiology, underwent pars plana Vitrectomy. A vitreous rebleed on the table and post-operatively, was the main complication encountered. Despite limited equipment, a visual improvement was obtained in 59.68% eyes with visual acuity greater than FC 6 meters in 33.87% eyes. This is far better than not being able to offer any treatment at all.

Adult↗
PubMed1991

Results of pars plana vitrectomy in 24 cases of endophthalmitis.

Twenty four cases of endophthalmitis were subjected to pars plana vitrectomy. A final vitreous clearance was obtained in 62.50% cases. Visual improvement occurred in 41.67% cases. It was concluded that prompt detection and early and vigorous therapy--medical and surgical--is the mainstay in the management of endophthalmitis.

Adolescent↗
PubMed1991

Intra-ocular lens implantation after vitreous loss.

Vitreous loss is a dreaded complication of cataract surgery, especially so with IOL implant which then may have to be abandoned. Thirty three cases of IOL implants, either anterior chamber or posterior chamber, after vitreous loss done in the past 3 years were studied. Of these, 18 (55%) had a final visual acuity of 6/18 or better and none was worse than 6/60. The postoperative complications and findings and a review of literature are discussed.

Adolescent↗
PubMed1985

Changes in atrial biopsies in chronic rheumatic heart disease. I: Cellulo-vascular and mesenchymal reaction.

The cellular, vascular and connective tissue changes were studied in 32 atrial biopsy specimens from patients with chronic rheumatic heart disease (RHD). 15 of these 32 specimens showed some inflammatory reaction, 7 with small mononuclear cells only and 8 with macrophage reaction amidst increased but necrotic collagen, especially in the subepicardial and subendocardial regions. Most cellulonecrotic foci were histologically consistent with a stage of Aschoff nodule. Acid phosphatase activity in frozen sections was seen in the cytoplasm of the macrophages. Fine structural examination showed membrane-bound vacuoles and lipofuscin bodies rather than ingested material in the macrophages. By light and electronmicroscopy, these macrophages were not different from those encountered in other granulomatous or necrotic conditions. There was moderate proliferation of blood vessels, with prominence of endothelial cells and pinocytotic vesicles, or fibrosis of media, or proliferation of basal laminae. The presence of Aschoff nodules in the right atrium, the least affected chamber in RHD, suggests a diffuse and smouldering pathology on the basis of a persistent subclinical cell-mediated immune (CMI) reaction.

Adolescent↗
PubMed1985

Changes in atrial biopsies in chronic rheumatic heart disease. II: Muscle fibre reaction.

Myocardial fibres were studied in the right atrial biopsies from 32 patients with chronic rheumatic heart disease (RHD). Paraffin and, particularly, araldite sections showed many muscle fibres well preserved, and others with large hyperchromatic nuclei, or with depleted myofibrils and increased mitochondria. With the SDH and ATPase reactions, there was no type difference in the myocardial fibres, and the former showed the reaction predominantly in the centre while the latter showed it mainly at the periphery of the fibres. At electronmicroscopy, fibres with intact myofibrils were found close to "degenerating" fibres with variable degrees of myofibrillar and myofilament disorganisation and loss, mitochondrial proliferation, occasionally with degeneration of cristae, and accumulation of lipofuscin in varying amounts, and irregularly tortuous or loosened intercellular junctions. This study has revealed more severe muscle changes than expected, even in the clinically less affected right atrial chamber in chronic RHD. It is speculated that this might be due to subclinical involvement of the tricuspid valve, known to be frequent in Indian patients, and the resulting "back pressure" on the right atrium might lead to changes in its myofibres.

Adolescent↗