Population structure of a whale shark Rhincodon typus aggregation in the Red Sea.

The presence of whale sharks Rhincodon typus were recorded around Shib Habil, a small, coastal reef off the Red Sea coast of Saudi Arabia, from 2010 to 2015. A total of 267 suitable photographs resulting in the identification of 136 individuals, were documented from 305 encounters. Sharks were divided evenly between the sexes with no evidence of temporal or spatial segregation. All individuals were immature based on size estimates and, for males, juvenile clasper morphology. Scars were reported for 57% of R. typus with 15% showing evidence of propeller trauma. Estimates of population size and patterns of residency were calculated by modelling the lagged identification rate. Multiple models were run simultaneously and compared using the Akaike information criterion. An open population model was found to best represent the data and estimates a daily abundance between 15 and 34 R. typus during the aggregation season, with local residence times ranging from 4 to 44 days. Residence times away from Shib Habil range from 15 to 156 days with a permanent emigration-death rate between 0·07 and 0·58 individuals year(-1) . These results are broadly similar to those from other aggregations of R. typus, although the observed sexual parity and integration found at this site is unique for the species and needs further study.

Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films.

Molecular orientation critically influences the mechanical, chemical, optical and electronic properties of organic materials. So far, molecular-scale ordering in soft matter could be characterized with X-ray or electron microscopy techniques only if the sample exhibited sufficient crystallinity. Here, we show that the resonant scattering of polarized soft X-rays (P-SoXS) by molecular orbitals is not limited by crystallinity and that it can be used to probe molecular orientation down to size scales of 10 nm. We first apply the technique on highly crystalline small-molecule thin films and subsequently use its high sensitivity to probe the impact of liquid-crystalline ordering on charge mobility in polymeric transistors. P-SoXS also reveals scattering anisotropy in amorphous domains of all-polymer organic solar cells where interfacial interactions pattern orientational alignment in the matrix phase, which probably plays an important role in the photophysics. The energy and q-dependence of the scattering anisotropy allows the identification of the composition and the degree of orientational order in the domains.

Pharmacokinetics of low-dose methotrexate in adult asthmatics.

Several reports have been published on the disposition of methotrexate (MTX) when given in low dosages, but none in asthmatic patients. To address this matter, pharmacokinetic studies were performed in nine patients with severe, steroid-requiring asthma (ages 18-76 yrs) after the sixth weekly intramuscular dose of MTX. Theophylline pharmacokinetic studies were also performed at baseline prior to the start of MTX treatment and at the time of the MTX studies. Total systemic clearance of MTX, given as mean (SD), was 122.6 (25.1) ml/minute, volume of distribution at steady state 0.49 (0.2) L/kg, half-life 3.1 (0.3) hours, mean residence time 5.0 (0.6) hours, and renal clearance 89.1 (36.3) ml/minute. These values are similar to those previously reported for other patient populations receiving low-dose MTX. Eight of these patients were evaluated for changes in theophylline pharmacokinetics. Theophylline clearance at week 6 decreased an average of 19% from baseline and correlated inversely with total MTX clearance. Percentage change in theophylline clearance from baseline was inversely correlated with MTX nonrenal clearance, but was not statistically significant. This finding may indicate competition for clearance pathways between MTX and theophylline.

Improving technology: blood glucose testing.

Nurses frequently monitor blood glucose at the patient's bedside, allowing timely assessment and interventions. To meet the Joint Commission on Accreditation of Health Organization's requirements and guidelines from National Committee on Clinical Laboratory Standards and College of American Pathologists, quality control compliance must be maintained. After testing three blood glucose monitors, one institution selected a machine that eliminated handwritten documentation, ensured quality control testing, and improved ease of use.

Effect of low-dose methotrexate on the disposition of glucocorticoids and theophylline.

Low-dose methotrexate (MTX) therapy has been recently proposed as alternative therapy for patients with severe steroid-requiring asthma. Several questions have been raised regarding the mechanism of action, including alteration of pharmacokinetics of two medications used in these patients, specifically, glucocorticoids and theophylline. To address this question, pharmacokinetic studies were performed at baseline and after 6 weeks of treatment with either intramuscular MTX or placebo (folic acid). Plasma concentrations of theophylline were measured by fluorescence polarization immunoassay (TDx, Abbott Diagnostics, Abbott Park, Ill.). Prednisolone, methylprednisolone, and cortisol concentrations were measured by high-performance liquid chromatography. Fifteen adults were enrolled in the double-blind, placebo-controlled trial. No change in prednisolone pharmacokinetic parameters was found. Theophylline clearance decreased an average of 19% in patients randomized to receive MTX, from 48.0 +/- 2.0 ml/hr/kg to 38.9 +/- 3.6 ml/hr/kg (p less than 0.05). This change resembles change observed with theophylline and phenobarbital clearance in which a high degree of interpatient variability is observed. The most likely explanation for the change in theophylline clearance is inhibition of hepatic microsomal enzyme activity. Three patients complained of adverse effects, and dosage was reduced in one patient. The variable effect of MTX on theophylline clearance indicates that theophylline concentration monitoring should be performed in patients receiving both drugs.

Lack of benefit of methotrexate in severe, steroid-dependent asthma. A double-blind, placebo-controlled study.

OBJECTIVE: To determine the effect of low-dose methotrexate in asthmatic patients on steroid use, asthma symptom scores, pulmonary function, airway reactivity, blood cellular components, and immunoglobulin E levels. DESIGN: A randomized, double-blind, parallel, placebo-controlled, 13-week clinical trial with follow-up of patients in an open trial of methotrexate at the conclusion of the double-blind study. SETTING: An asthma care outpatient clinic. PATIENTS: From February 1988 to March 1990, 19 patients with severe, steroid-dependent asthma were enrolled in the study. Two of these patients were excluded from analysis. INTERVENTIONS: Patients were administered methotrexate or placebo intramuscularly, to assure complete absorption, once weekly during the 13-week study. RESULTS: Patients on methotrexate and placebo both significantly decreased their steroid dose by 39.6% (95% CI, 25.1% to 54.1%, P = 0.001) and 40.2% (CI, 17.9% to 67.4%, P = 0.003), respectively. Pulmonary function did not differ significantly between the methotrexate and placebo groups. In addition, airway reactivity and symptom scores were unchanged on methotrexate or placebo. No significant toxicities were seen during the course of the 13-week blinded study, but one patient on methotrexate and prednisone in the follow-up period developed Pneumocystis carinii pneumonia and died. Despite continuing methotrexate for up to 1 year, and increasing methotrexate to 30 mg weekly, no significant benefit of methotrexate on asthma control could be shown. CONCLUSION: Our study does not support the use of methotrexate in the treatment of severe asthma.