Evaluation of in vitro activities of extracellular enzymes from Aspergillus species isolated from corneal ulcer/keratitis.

Mycotic/fungal keratitis is a suppurative, generally ulcerative infection of the cornea. The filamentous fungi, Aspergillus spp. are the second leading cause of mycotic keratitis, particularly in India. Aspergillus spp. produce a range of extracellular enzymes that are used to break down complex molecules and used for growth and reproduction, also for survival on/in host organism. The current study was designed with an objective to screen in vitro extracellular enzyme activity of Fusarium and Aspergillus isolates from mycotic keratitis patients and to correlate the same as a putative virulence factor. Extracellular enzymes viz., deoxyribonuclease (DNase), protease, lipase, elastase, keratinase, etc., produced by Aspergillus have key role in keratomycosis and hence their (n = 85) in vitro activities were investigated. It was found that, the majority of the Aspergillus isolates produced protease (n = 75; 88% of 85) followed by lipase (n = 59; 69% of 85), DNase (n = 35; 41% of 85), elastase (n = 26; 31% of 85) and keratinase (n = 13; 15% of 85). The enzyme activity indices (EAI) for DNase, elastase, protease and lipase ranged between 1.01 and 1.98, whereas elastase EAI varied between 1.26 and 1.92. DNase, protease and lipase showed a maximum EAI of 1.98 and lowest EAI value of 1.01, respectively. Extracellular enzymes of Aspergillus spp. may have potential role in the onset and progression of keratitis.

Genetic characterization of fluoroquinolone-resistant Escherichia coli associated with bovine mastitis in India.

AIM: The present study was undertaken to characterize the mutation in gyrA (DNA gyrase) and parC (topoisomerase IV) genes responsible for fluoroquinolone resistance in Escherichia coli isolates associated with the bovine mastitis. MATERIALS AND METHODS: A total of 92 milk samples from bovine mastitis cases were sampled in and around Puducherry (Southern India). Among these samples, 30 isolates were bacteriologically characterized as E. coli. Minimum inhibitory concentrations (MIC) of fluoroquinolones of these 30 E. coli isolates were evaluated by resazurin microtiter assay. Then, the quinolone resistance determining region (QRDR) (gyrA and parC genes) of these E. coli isolates was genetically analyzed for determining the chromosomal mutation causing fluoroquinolone resistance. RESULTS: E. coli isolates showed a resistance rate of 63.33%, 23.33% and 30.03% to nalidixic acid, ciprofloxacin and enrofloxacin, respectively. Mutations were found at 83(rd) and 87(th) amino acid position of gyrA gene, and at 80(th) and 108(th) amino acid position of parC gene in our study isolates. Among these five isolates, one had a single mutation at 83 amino acid position of gyrA with reduced susceptibility (0.5 µg/ml) to ciprofloxacin. Then, in remaining four isolates, three isolates showed triple mutation (at gyrA: S83⟶L and D87⟶N; at parC: S80⟶I) and the fifth isolate showed an additional mutation at codon 108 of parC (A108⟶T) with the increased ciprofloxacin MIC of 16-128 µg/ml. The most common mutation noticed were at S83⟶L and D87⟶N of gyrA and S80⟶I of ParC. CONCLUSION: The study confirms the presence of mutation/s responsible for fluoroquinolone resistance in QRDR of gyrA and parC genes of E. coli isolates of animal origin, and there is increased rate of fluoroquinolone resistance with high-level of MIC. The mutations observed in this study were similar to that of human isolates.

Hereditary arrhythmia corner: learning from challenging patients. Family with suspect LQTS.

A brother and sister, presented to our Arrhythmia Clinic for evaluation of possible long QT syndrome (LQTS). They are 18 and 15 years of age, respectively. Their mother has been diagnosed with LQTS and the family history is remarkable for a number of sudden deaths. The electrocardiogram (ECG) of the sister is presented in Figure 1. The siblings had been followed by pediatric cardiology since infancy and now they are referred for further evaluation. They are both asymptomatic and very active teenagers, and are not on any medications. Echocardiograms were normal. Holter monitoring also did not show any rhythm abnormalities in either sibling.The mother had been evaluated as a teenager when she had a presyncopal episode while running track in high school. Her QT interval on one 12-lead tracing showed borderline prolonged QT. She had originally been started on beta-blockers, but she had taken herself off of these over the years. The family history is significant for sudden deaths in several distant relatives. In addition, the mother's aunt had an abnormal ECG in the setting of multiple syncopal episodes. In the interim, she had been treated with beta-blockers.

Small-angle X-ray scattering and near-infrared vibrational spectroscopy of water confined in aerosol-OT reverse micelles.

The state of water confined in Aerosol-OT-hydrocarbon-water reverse micelles with cyclohexane, n-pentane, n-octane, and n-dodecane as apolar solvents is investigated by small-angle X-ray scattering and near-infrared vibrational spectroscopy of the first overtone of the OH stretching mode of water. The experiments focus on water/AOT molecular ratios W(0)=2-20, where water is strongly affected by the confinement and surface-water interactions. The pair-distance distribution functions derived from the small-angle scattering patterns allows a detailed characterization of the topology of these systems, and they indicate deviations from monodisperse, spherical water pools for some of these hydrocarbon systems. In contrast to a common assumption, the pool size does not scale linearly with W(0) in going from dry reverse micelles (W(0)-->0) to essentially bulk-like water (W(0)>20). The first overtone of the OH-stretching vibration exhibits highly structured spectra, which reveal significant changes in the hydrogen bonding environment upon confinement. The spectra are rationalized by a core/shell model developed by Fayer and co-workers. This model subdivides water into core water in the interior of the micelle and shell water close to the interface. Core water is modelled by the properties of bulk water, while the properties of shell water are taken to be those of water at W(0)=2. The model allows the representation of the spectra at any hydration level as a linear combination of the spectra of core and shell water. Different approaches are critically reviewed and discussed as well.

Evaluation and treatment of resistant hypertension.

Hypertension is a major cause and contributor to stroke, heart and kidney disease. Despite the development of an arsenal of medication to treat hypertension over the past half-century, adequate treatment continues to be a major problem in the United States. The Third National Health and Nutrition Examination Survey (NHANES-III) shows that only 29% of hypertensive patients reach a blood pressure less than 140/90 mm Hg. Resistant hypertension is defined as a blood pressure greater than 140/90 mm Hg despite a rational combination of three or more blood pressure medications including a diuretic. The prevalence of true resistant hypertension in hypertension clinics is only about 11-13%. Higher prevalence rates are evident in populations with evidence of end-organ disease such as cardiac or renal disease where lower blood pressure targets have now been established. Ascertaining the possible cause(s) for resistant hypertension is a challenge to all clinicians, but critical in eventual determination of a therapeutic solution. The following review will hopefully help guide clinicians in their discernment of causes and potential treatments for resistant hypertension. The diagnosis and treatment of the more common secondary causes will be described and treatment options for patients with resistant hypertension are discussed. Newer options, some still under clinical investigation, will be described and their future utility will be discussed. (Cardiol J 2007; 14: 329-339).