Pulse Wave Velocity as a Marker of Severity of Coronary Artery Disease

To determine whether pulse wave velocity (PWV) as a measure of arterial stiffness is a marker of coronary artery diseases (CAD), the authors did a cross-sectional study in 92 patients undergoing coronary angiography for suspected CAD. Arterial stiffness was assessed through recording PWV from the left carotid–right femoral arteries using an automated machine. The mean PWV was higher in patients with CAD than in those without CAD (11.13±0.91 vs 8.14±1.25 m/sec; P< .001). When the severity of CAD was expressed as 1-, 2-, and multiple-vessel disease, there was a significant association between the severity of CAD and PWV. PWV differed significantly with different categorical severity of CAD even when age and total cholesterol were controlled for. In a univariable analysis, PWV was higher with higher systolic blood pressure (P< .004). The authors conclude that arterial stiffness measured through PWV is an independent and complementary cardiovascular risk marker.     

Evaluation of a new Etest vancomycin-teicoplanin strip for detection of glycopeptide-intermediate Staphylococcus aureus (GISA), in particular, heterogeneous GISA

Glycopeptide-intermediate Staphylococcus aureus (GISA) and, in particular, heterogeneous GISA (hGISA) are difficult to detect by standard MIC methods, and thus, an accurate detection method for clinical practice and surveillances is needed. Two prototype Etest strips designed for hGISA/GISA resistance detection (GRD) were evaluated using a worldwide collection of hGISA/GISA strains covering the five major clonal lineages. A total of 150 strains comprising 15 GISA and 60 hGISA strains (defined by population analysis profiles-area under the curve [PAP-AUC]), 70 glycopeptide-susceptible S. aureus (GSSA) strains, and 5 S. aureus ATCC reference strains were tested. For standardized Etest vancomycin (VA) MIC testing, the modified Etest macromethod with VA and teicoplanin (TP) strips tested with a heavier inoculum using brain heart infusion agar (BHI) and two glycopeptide screening agar plates (6 μg/ml VA/BHI and 5 μg/ml Mueller-Hinton agar [MHA]) were tested in parallel with the two new Etest GRD strips: a VA 32 (0.5-μg/ml)-TP 32 (0.5-μg/ml) double-sided gradient (E-VA/TP) with one prototype overlaid with a nutrient (E-VA/TP+S) to enhance the growth of hGISA. The Etest GRD strips were tested with a standard 0.5-McFarland standard inoculum using MHA and MHA plus 5% blood (MHB) and were read at 18 to 24 and 48 h. The interpretive MIC cutoffs used for the new Etest GRD strips at 24 and 48 h were as follows: for GISA, TP or VA, ≥8, and a standard VA MIC of ≥6; for hGISA, TP or VA, ≥8, and a standard VA MIC of ≤4. The results on MHB at 48 h showed that E-VA/TP+S had high specificity (94%) and sensitivity (95%) in comparison to PAP-AUC and was able to detect all GISA (n = 15) and 98% of hGISA (n = 60) strains. In contrast, the glycopeptide screening plates performed poorly for hGISA. The new Etest GRD strip (E-VA/TP+S), utilizing standard media and inocula, is a simple and acceptable tool for detection of hGISA/GISA for clinical and epidemiologic purposes.     

Chlorella vulgaris Ameliorates Oxidative Stress and Improves the Muscle Regenerative Capacity of Young and Old Sprague-Dawley Rats

Muscle atrophy in ageing is a multifactorial degenerative process impacted by cellular ageing biology, which includes oxidative stress. Chlorella vulgaris is a coccoid green eukaryotic microalga rich in antioxidants. The aim of this study was to determine the effect of C. vulgaris in ameliorating oxidative stress, thus elucidating its mechanism in improving muscle mass, strength and function in young and old rats. Fifty-six male Sprague-Dawley (SD) rats aged 3 months (young) and 21 months (old) were divided into three groups: Group 1 (control) was given distilled water; Group 2 was treated with 150 mg/kg body weight (BW) of C. vulgaris; and Group 3 was treated with 300 mg/kg BW of C. vulgaris for three months. Grip and muscle strength and muscle integrity were determined on days 0, 30, 60, and 90 of treatment. Urine and blood were collected on days 0 and 90 of treatment for oxidative stress marker determination, while the gastrocnemius muscles were collected for muscle oxidative stress analysis. Increased grip strength of the front and hind paws was observed in young C. vulgaris-treated rats on days 30, 60, and 90 compared to the untreated control on the same days (p < 0.05). There was a significant increase in lean bone mineral content (BMC) in young rats treated with 300 mg/kg BW C. vulgaris compared to untreated rats on days 30 and 60. The fat mass was significantly decreased in young and old C. vulgaris-treated rats on day 90 compared to the untreated control. The total path was significantly increased for old rats treated with 300 mg/kg BW C. vulgaris on days 60 and 90 compared to day 0. Young and old C. vulgaris-treated rats demonstrated a significant decrease in urinary isoprostane F_2t and plasma creatine kinase-MM (CKMM) compared to the control on day 90. A significant decrease in malondialdehyde (MDA) and 4-hydroxyalkenal (HAE) levels were observed in young and old rats treated with C. vulgaris. C. vulgaris improved the muscle mass, strength, and function in young and old rats. This effect could be due to its potency in ameliorating oxidative stress in the skeletal muscle of young and old rats.     

Flexible chitin films as potential wound-dressing materials: wound model studies

Chitin films possessing increased flexibility, softness, transparency, and conformability have been prepared. These attributes enable the potential application of chitin films as occlusive, semipermeable film wound dressings similar to commercial products such as Opsite trade mark. The chitin films are generally nonabsorbent, exhibiting a total weight gain of only up to 120-160% in physiological fluid. Dry chitin films transpire water vapor at a rate of about 600 g/m(2)/24 h, similar to commercial polyurethane-based film dressings, but rises to 2400 g/m(2)/24 h, when wet, which is higher than the water vapor transmission rate of intact skin. The chitin films are nontoxic to human skin fibroblasts, maintaining 70-80% cell viability. Wound studies using a rat model showed no signs of allergenicity or the high inflammatory response associated with biodegradable biomaterials. The chitin films displayed accelerated wound-healing properties. Based on histological examination, wound sites dressed with the chitin films stabilized and healed faster, and appeared stronger than those dressed with Opsite trade mark and gauze dressings after 7 days of healing.     

Comparison of method-specific vancomycin minimum inhibitory concentration values and their predictability for treatment outcome of meticillin-resistant Staphylococcus aureus (MRSA) infections

The objectives of this study were to examine the predictive value of method-specific vancomycin (VAN) minimum inhibitory concentration (MIC) results on treatment outcomes of meticillin-resistant Staphylococcus aureus (MRSA) infections. VAN MIC values for MRSA strains were determined using Etest, VITEK-1, MicroScan (MScan) and broth microdilution (BMD), with additional screening for heterogeneous glycopeptide-intermediate S. aureus (hGISA) phenotype. Patients' charts were reviewed for outcome correlation. Performance characteristics of method-specific VAN MICs in predicting outcome were compared. Most (76%) of the 92 strains tested caused pneumonia or bacteraemia. The majority of strains tested (>70%) had a VAN MIC >1mg/L by Etest or MScan compared with 41% by Vitek and 7% by BMD. Agreement between test methods for high versus low MICs (>1mg/L vs. < or = 1mg/L) ranged from 36% to 71%. High versus low VAN MICs by Etest differentiated response of invasive strains to VAN. Performance characteristics (sensitivity/specificity/positive predictive value/negative predictive value) were: Etest, 55/81/89/38%; and Vitek, 56/62/81/32/%, respectively. Eight strains (9%) demonstrated a hGISA phenotype; more yielded high MICs by Etest, MScan and Vitek than BMD (87%, 87% and 75% vs. 50%). In conclusion, VAN MIC testing methods produce highly variable results. The Etest method appears to be relatively more reliable in predicting treatment response and yielded higher MICs for strains with a hGISA phenotype.