Platelet polymorphisms: frequency distribution and association with coronary artery disease in an Indian population

Platelets play a critical role in normal blood hemostasis and thrombus formation in myocardial infarction (MI). Several polymorphisms of genes involved in platelet activation and fibrinolysis have been reported to be associated with MI. The aim of the present study was to determine the frequency distribution and association of polymorphisms in these genes with coronary artery disease (CAD) among Indians. A case-control genetic association study was performed for polymorphisms in platelet glycoprotein receptors (GPIIb/IIIa [HPA1a/1b], GPIb-IX-V [VNTR], and GPIa/IIa [C807T]), fibrinogen β-chain (BclI), α-chain (Aα312), tissue plasminogen activator (tPA) [I/D] and plasminogen activator inhibitor-I (PAI-1) [4G/5G] in 473 healthy controls and 446 patients with stable and unstable angina. Genotyping was either by PCR-based restriction endonuclease digestion or allele-specific primers. The I allele frequency of the tPA I/D polymorphism was significantly higher in our patients (χ(2)=7.33, P<0.01) and no other polymorphisms varied significantly between patients and controls. Also, none of the polymorphisms seemed to affect the severity of the disease, the only exception being the mutant alleles of β chain of fibrinogen gene, which were significantly elevated in single vessel disease. This is the first study to evaluate the role of gene polymorphisms in both the thrombotic and fibrinolytic pathway in the Indian population and suggests that tPA I/D polymorphism confers CAD risk in our population.     

Effects of tetrahydrobiopterin on coronary vascular reactivity in atherosclerotic human coronary arteries

OBJECTIVES: Reduced nitric oxide (NO) bioavailability is a key mechanism in the development of endothelial dysfunction. The NO synthase cofactor, tetrahydrobiopterin (BH4), increases NO availability, yet its effect in the human coronary circulation, particularly following PCI, remains uncertain. This study was designed to evaluate the effects of intracoronary BH4 in human coronary arteries with non-critical coronary artery disease or following percutaneous coronary intervention (PCI). METHODS: The study group consisted of 57 stable patients, 10 of which were controls. Active drug was administered in 47 patients, with either de novo non-critical coronary disease (non-stent group; n=25) or following PCI (stent group; n=22). Coronary blood flow (CBF) was measured (0.014-inch Doppler flow wire) in each of these groups in response to sequential intracoronary infusions of acetylcholine (Ach, 10(-7) & 10(-6) M), BH4 (250 mug/min & 500 mug/min) and a co-infusion of BH4 (500 mug/min) and Ach (10(-7) & 10(-6) M). The primary endpoint evaluated the % change in CBF to Ach compared to co-infusion of Ach and BH4. RESULTS: Mean age was 60+/-10 years (M 45:F 12). Regarding the primary hypothesis, no difference was observed between Ach response compared to co-infusion of BH4 and Ach in the % change in CBF in either the non-stent group (Ach 97+/-122%, Ach/BH4 87+/-95%) or the stent group (Ach 77+/-105%, Ach/BH4 55+/-97%). CONCLUSIONS: In native non-critical coronary artery disease or following PCI, coronary microvascular endothelial function is not improved by co-administration of Ach and BH4.     

Serum sickness-like reaction to cefuroxime: a case report and review of the literature

We report a case of a 34-year-old woman who received cefuroxime, a second-generation cephalosporin, as treatment for mastitis. She subsequently developed a serum sickness-like reaction (SSLR) with a generalized pruritic rash, joint pains, and fever. She improved upon treatment with systemic steroids. SSLR is well-described to cefaclor, a second-generation cephalosporin. However, there is a paucity of reports of SSLR to other cephalosporins such as this case.     

Longitudinal analysis of genotype distribution of influenza A virus from 2003 to 2005

Influenza A viruses cause yearly epidemics, in part, due to their ability to overcome immunity from previous infections through acquisition of mutations. Amino acid sequences encoded by genes 4 (HA), 6 (NA), 7 (M), and 8 (NS) from 77 H3N2 influenza A isolates, collected between November 2003 and March 2005, were analyzed to determine the extent to which the viruses mutated within epidemic periods and between the epidemics. Nucleotide and amino acid sequences were stable throughout the epidemics but experienced substantial changes between epidemics. Major changes occurred in the HA gene in 5 to 7 amino acids and the NA gene in 11 to 13 amino acids and changes of 5 amino acids occurred in the M and NS genes. In the HA gene, changes occurred in sites known to be epitopes that determine the hemagglutination inhibition reactivity, and these were shown to be associated with a change of strain from A/Fujian/411/2002-like to A/California/7/2004-like viruses. Our findings indicate that genotype determination promises to be a rapid approach for detecting new strains of influenza A viruses in a population.     

Adhesion molecules close homolog of L1 and tenascin-C affect blood-spinal cord barrier repair

Mice deficient in the recognition molecules, close homolog of L1 (CHL1) and tenascin-C, show improved and reduced functional recovery, respectively, after spinal cord injury compared with wild-type littermates. In this study, we addressed the question whether the differential functional outcome was paralleled by differences in blood-spinal cord barrier (BSCB) repair in the two mouse strains. We conducted spinal cord compression injuries in knock-out and wild-type mice. BSCB permeability was assessed by measuring the Evans blue spread within the spinal cord tissue at 14-21 days after injury. Results show that CHL1 reduces and tenascin-C enhances BSCB permeability, suggesting a correlation between functional outcome and BSCB repair.     

Controlling hydrogelation kinetics by peptide design for three-dimensional encapsulation and injectable delivery of cells

A peptide-based hydrogelation strategy has been developed that allows homogenous encapsulation and subsequent delivery of C3H10t1/2 mesenchymal stem cells. Structure-based peptide design afforded MAX8, a 20-residue peptide that folds and self-assembles in response to DMEM resulting in mechanically rigid hydrogels. The folding and self-assembly kinetics of MAX8 have been tuned so that when hydrogelation is triggered in the presence of cells, the cells become homogeneously impregnated within the gel. A unique characteristic of these gel-cell constructs is that when an appropriate shear stress is applied, the hydrogel will shear-thin resulting in a low-viscosity gel. However, after the application of shear has stopped, the gel quickly resets and recovers its initial mechanical rigidity in a near quantitative fashion. This property allows gel/cell constructs to be delivered via syringe with precision to target sites. Homogenous cellular distribution and cell viability are unaffected by the shear thinning process and gel/cell constructs stay fixed at the point of introduction, suggesting that these gels may be useful for the delivery of cells to target biological sites in tissue regeneration efforts.     

Re-amputation occurrence in the diabetic population in South Wales, UK

The incidence of re-amputation following lower extremity amputations (LEA) among the diabetic patients referred to the Artificial Limb and Appliance Centers (ALAC) in South Wales, UK, was investigated. Manual and electronic data-gathering systems were used to extract the medical records of 473 people with various causes of LEA referred to the ALAC in South Wales during 2001-2003. The data included demographic information, causes of amputation and occurrence of various levels of re-amputation. Two hundred and five subjects with diabetes underwent 316 amputations, 44 were foot amputations and 272 major amputations on the ipsilateral and contra-lateral sides. Of the diabetic patients, 45.9% with single LEA underwent re-amputations with 22% incidence of contra-lateral LEA within 2 years. In comparison, 15% underwent re-amputations in the non diabetic dysvascular patients. Ipsilateral re-amputations occurred much earlier (average 21 weeks) compared with the contra-lateral amputations which took an average of 82 weeks following the first amputation. Nearly half of the diabetic patients with single LEA referred for rehabilitation underwent re-amputations within 2 years; out of which 22% of the patients underwent contra-lateral LEA. Although the progression of level of amputations does not follow a particular pattern, re-amputation on the contra-lateral side occurred almost four times later than that on the ipsilateral side.     

Comparative study of dot enzyme immunoassay (Typhidot-M) and Widal test in the diagnosis of typhoid fever

We compared the sensitivity and specificity of Typhidot-M and Widal test with blood culture (gold standard) for diagnosing typhoid fever in 105 children aged 1–15 years admitted with clinical suspicion of typhoid fever. Of the 105 cases, blood culture was positive for S.typhi in 41 (39%) children, Widal test was positive in 48 (45.7%) and Typhidot-M was positive in 78 (74.3%) cases. Sensitivity and specificity of Typhidot-M was 92.6% and 37.5% while sensitivity and specificity of Widal test was 34.1% and 42.8%, respectively. In children with fever of less than 7 days duration, Typhidot-M was positive in 97%, compared to 24.2% by Widal test. Typhidot-M is a simple and sensitive test for early diagnosis of typhoid fever in children.