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Biomedical subjects

Usman Ahmad

Publications and source records attributed to Usman Ahmad.

13 recordsLinked to original sources
PubMed2006

A novel haplotype in ABCA1 gene effects plasma HDL-C concentration.

BACKGROUND AND OBJECTIVES: ATP-binding cassette transporter 1 (ABCA1) is a trans-membrane protein responsible for the efflux of cholesterol and phospholipids across the cell membrane, an essential step in the reverse cholesterol transport system. This study investigates the effect of five non-synonymous SNPs of ABCA1 gene on plasma HDL-C levels in Pakistani individuals free of ischemic heart disease and stroke. METHODS: Five non-synonymous SNPs were selected after sequencing ABCA1 gene in patients of Hypoalphalipoproteinemia. The presence of these SNPs was then checked in 200 individuals by using PCR-RFLP. Plasma glucose and lipid fractions were measured in fasting state. Ethical approval was obtained from the Ethical Review Committee, Aga Khan University and informed consent was obtained from all subjects. RESULTS: LL genotype of V825L polymorphism was associated with decreased levels of HDL-C [-0.17 (-0.32 to -0.19); P=0.02] and P774 allele showed a significant increase in HDL-C levels as compared to T774 allele [-0.15 (-0.18 to -0.02); P=0.01]. R219K, A399V and V771M polymorphisms did not show any association with levels of HDL-C, LDL-C, cholesterol and triglycerides. Haplotype analysis between R219K and V825L polymorphisms showed a unique interaction between R219 allele and L825 allele. The RL haplotype was found to be associated with decreased levels of HDL-C [-0.12 (-0.22 to -0.03); P=0.001]. CONCLUSIONS: ABCA1 polymorphisms are associated with varying levels of HDL-C in Pakistani individuals. These results warrant further investigations as ABCA1 polymorphisms may have a major role in the high incidence of cardiovascular disorders in South Asians.

ATP Binding Cassette Transporter 1↗
PubMed2006

Association of endothelial nitric oxide synthase gene G894T polymorphism with essential hypertension in an adult Pakistani Pathan population.

This retrospective, case-control study was carried out to find putative correlations of eNOS G894T polymorphism with essential hypertension (EHT) amongst adult Pakistani Pathans. We investigated a sample population of 332 (154 men, 178 women) comprising groups of 146 hypertensives (HTs) and 186 normotensives (NTs) by assays based on polymerase chain reaction followed by restriction endonuclease analysis. The distribution of the genotypes or alleles was not statistically different in hypertensive and normotensive groups. In conclusion, the present study in a population of Pakistani adult Pathans does not support the association of the eNOS gene G894T polymorphism to essential hypertension.

Case-Control Studies↗
PubMed2006

Coronary heart disease in south Asia: need to redefine risk.

South Asian population has a high incidence of coronary artery disease. There are a number of risk factors that are almost unique to the south Asians. The classical risk factors do not account for such high rates of CHD as are present in south Asia. We have discussed some important aspects of CHD that can help in improving prevention in south Asia.

Asia↗
PubMed2006

Tuberculous hilar lymph nodes leading to tracheopulmonary artery fistula and pseudoaneurysm of pulmonary artery.

Tracheopulmonary artery fistula is an extremely rare condition. We report the case of an 80-year-old man who presented with massive hemoptysis. He was found to have tuberculous mediastinal lymph nodes that had eroded into the pulmonary artery and anterior tracheal wall, leading to a pseudoaneurysm of the right pulmonary artery and a tracheopulmonary artery fistula.

Aged, 80 and over↗
PubMed2006

Translating the chronic care model into the community: results from a randomized controlled trial of a multifaceted diabetes care intervention.

OBJECTIVE: To determine whether using the chronic care model (CCM) in an underserved community leads to improved clinical and behavioral outcomes for people with diabetes. RESEARCH DESIGN AND METHODS: This multilevel, cluster-design, randomized controlled trial examined the effectiveness of a CCM-based intervention in an underserved urban community. Eleven primary care practices, along with their patients, were randomized to three groups: CCM intervention (n = 30 patients), provider education only (PROV group) (n = 38), and usual care (UC group) (n = 51). RESULTS: A marked decline in HbA(1c) was observed in the CCM group (-0.6%, P = 0.008) but not in the other groups. The magnitude of the association remained strong after adjustment for clustering (P = 0.01). The same pattern was observed for a decline in non-HDL cholesterol and for the proportion of participants who self-monitor blood glucose in the CCM group (non-HDL cholesterol: -10.4 mg/dl, P = 0.24; self-monitor blood glucose: +22.2%, P < 0.0001), with statistically significant between-group differences in improvement (non-HDL cholesterol: P = 0.05; self-monitor blood glucose: P = 0.03) after adjustment. The CCM group also showed improvement in HDL cholesterol (+5.5 mg/dl, P = 0.0004), diabetes knowledge test scores (+6.7%, P = 0.07), and empowerment scores (+2, P = 0.02). CONCLUSIONS: These results suggest that implementing the CCM in the community is effective in improving clinical and behavioral outcomes in patients with diabetes.

Aged↗
PubMed2006

Tracheal inujry due to blunt chest trauma: a rare surgical emergency.

Tracheal injury is a rare complication of blunt chest trauma. The patients usually present with signs of respiratory distress. Primary repair is the treatment of choice in case of large defects, while small tears can be managed conservatively. Immediate operation is recommended to improve deteriorating pulmonary function. The decrease in mortality and long-term morbidity depends on early diagnosis. We report a case of tracheal injury due to non-penetrating thoracic trauma which was successfully managed with surgery.

Accidents, Traffic↗
PubMed2005

Concomitant presence of subtypes of left coronary artery disease.

OBJECTIVE: To study the risk profile associated with surgical revascularization for mixed left main and left main equivalent diseases. METHODS AND RESULTS: Retrospective analysis of medical records of patients who underwent CABG from January 1997 and December 2002 were studied. 210 patients were included of which 30.5% (64) had left main, 49.5% (104) had left main equivalent and 20% (42) had mixed type of stenotic disease. The mixed type left coronary disease was associated with very high post-operative mortality. The factors associated with mortality were degree of left main artery stenosis, cardiopulmonary bypass pump time, no. of packed cell units transfused during surgery, post-operative low cardiac output, re-exploration of chest and no. of days spent as intubated. Low cardiac output, chest re-exploration and no. of days intubated were independently associated with mortality. CONCLUSIONS: "Mixed left main and left main equivalent disease" makes a large proportion of left sided CAD. It is a unique subtype associated with very high risk, and it should be treated with extra caution. Characterization of its risk profile should be done with larger studies to improve the outcome.

Aged↗
PubMed2005

Strong association of a renin intronic dimorphism with essential hypertension.

The objectives of this project were two-fold: to identify the genetic mutation that has been detected as an MboI dimorphism in intron 9 of the human renin (REN) gene and to confirm a previously reported, putative association between the REN MboI dimorphism and clinical diagnosis of essential hypertension (EHT) in a population of Gulf Arabs from the United Arab Emirates. Sequencing of the MboI dimorphic site was carried out on DNA of randomly chosen cases and controls. A retrospective case-control study was carried out in 689 unrelated subjects (326 first-time, clinically diagnosed hypertensives and 363 age- and gender-matched normotensive subjects), selected from the resident population of the Abu Dhabi Emirate. A polymerase chain reaction/MboI-RFLP based method was employed to compare genotype and allele distributions. Nucleotide sequences at the MboI site of the cut and uncut alleles were determined to be GATC and GGTC, respectively. This A>G mutation is located 10,631 base pairs (bp) 3' to the start of the REN gene, and 79 bp 3' to the end of exon 9. The genotype distributions of the REN 10631A>G dimorphism were found to be significantly different between hypertensive and normotensive subjects (x2= 42.29, df=2, p<0.001). Frequencies of A alleles were 0.54 in EHT vs. 0.37 in normotensive subjects, which is even more demarcated than what was found previously. The frequency of AA genotypes was higher in the hypertensive group than in the normotensive group (34.7% vs. 14.0%). The quantification of the association of A alleles with increased risk of EHT was assessed with corresponding odds ratios (OR), which gave the following values: OR of GG vs. AG genotypes, 1.3 (95% confidence interval [CI]: 0.90-1.88); OR of GG vs. AA, 3.75 (95% CI: 2.41-5.86). In conclusion, REN 10631A alleles are significantly associated with EHT in the Emirati population. This has now been found in two different and therefore independent sample populations from the Abu Dhabi Emirate. Moreover, this genetic effect seems to be acting in a recessive fashion. Hence, either the REN gene itself, or another gene that is in linkage disequilibrium with REN 10631A>G, is implicated in the pathogenesis of EHT in Emirati.

Adult↗