Patterns of Activity Expressed by Juvenile Horseshoe Crabs

Adult American horseshoe crabs, Limulus polyphemus, possess endogenous circadian and circatidal clocks controlling visual sensitivity and locomotion, respectively. The goal of this study was to determine the types of activity rhythms expressed by juvenile horseshoe crabs (n = 24) when exposed to a 14:10 light/dark cycle (LD) for 10 days, followed by 10 days of constant darkness (DD). Horseshoe crab activity was recorded with a digital time-lapse video system that used an infrared-sensitive camera so animals could be monitored at night. In LD, 15 animals expressed daily patterns of activity, 6 displayed a circatidal pattern, and the remaining 3 were arrhythmic. Of the 15 animals with daily patterns of locomotion, 7 had a significant preference (P \u3c 0.05) for diurnal activity and 3 for nocturnal activity; the remainder did not express a significant preference for day or night activity. In DD, 13 horseshoe crabs expressed circatidal rhythms and 8 maintained a pattern of about 24 h. Although these results suggest the presence of a circadian clock influencing circatidal patterns of locomotion, these apparent circadian rhythms may actually represent the expression of just one of the two bouts of activity driven by the putative circalunidian clocks that control their tidal rhythms. Overall, these results indicate that, like adults, juvenile horseshoe crabs express both daily and tidal patterns of activity and that at least one, and maybe both, of these patterns is driven by endogenous clocks

A Study of Practices and Procedures used to Prepare Competent Group Leaders by Instructors in CACREP-Accredited Master's Level Group Courses

This study identified the practices and procedures of instruction that is being implemented by group counseling instructors at CACREP-accredited institutions. A survey questionnaire developed by the researcher was used to gather data from 160 CACREP-accredited counseling units across the United States. The survey was designed to collect input from group instructors on how the didactic, practicum, and experiential components of the master's level group course are being implemented. Three assumptions were made in conducting this study: 1.) The majority of master's level group instructors will report that they use a didactic component in preparing students to become effective group leaders, 2.) The majority of master's level group instructors will report that they use an experiential component in preparing students to become effective group leaders, and 3.) The majority of master's level group instructors will report that they use a practicum component in preparing students to become effective group leaders. The survey questionnaire and, consequently, the results were divided into the respective sections of didactic, experiential, and practicum. The results indicated that each of these components were utilized in the instruction of master's level group courses

Truths and Lies from the Polysomnography ECG Recording: An Electrophysiologist Perspective

Polysomnography remains the gold standard for diagnosis of Sleep Apnea (SA) and evaluation of the apnea/hypopnea index (AHI) which is used as the primary index of SA severity. The electrocardiogram (typically a single lead) obtained during the polysomnographic study is usually used to report the association between SA and cardiac rhythm disturbances. These findings help in guiding medical decisions but they could also represent a source for confusion. Electrophysiologists are frequently consulted to determine whether interventions need to be taken. We present 2 cases where the ECG during a polysomnography study required the intervention of an electrophysiologist to help with management

Comparing Maps of Mean Monthly Surface Temperature and Precipitation for Alaska and Adjacent Areas of Canada Produced by Two Different Methods

Maps of mean monthly surface temperature and precipitation for Alaska and adjacent areas of Canada, produced by Oregon State University’s Spatial Climate Analysis Service (SCAS) and the Alaska Geospatial Data Clearinghouse (AGDC), were analyzed. Because both sets of maps are generally available and in use by the community, there is a need to document differences between the processes and input data sets used by the two groups to produce their respective set of maps and to identify similarities and differences between the two sets of maps and possible reasons for the differences. These differences do not affect the observed large-scale patterns of seasonal and annual variability. Alaska is divided into interior and coastal zones, with consistent but different variability, separated by a transition region. The transition region has high interannual variability but low long-term mean variability. Both data sets support the four major ecosystems and ecosystem transition zone identified in our earlier work. Differences between the two sets of maps do occur, however, on the regional scale; they reflect differences in physiographic domains and in the treatment of these domains by the two groups (AGDC, SCAS). These differences also provide guidance for an improved observational network for Alaska. On the basis of validation with independent in situ data, we conclude that the data set produced by SCAS provides the best spatial coverage of Alaskan long-term mean monthly surface temperature and precipitation currently available.On a analysé des cartes représentant les moyennes mensuelles des précipitations et des températures de l’air en surface pour l’Alaska et les zones contiguës du Canada. Ces cartes avaient été établies par le service d’analyse du climat spatial (SCAS) de l’université de l’Oregon et le centre d’échange de données géospatiales de l’Alaska (AGDC). Vu qu’en général le public peut se procurer les deux ensembles de cartes et qu’il les utilise, il est nécessaire de documenter les différences entre les processus et les jeux de données d’entrée utilisés par les deux groupes pour créer leur propre ensemble de cartes, ainsi que de dégager les similarités et les différences entre les deux ensembles de cartes et les raisons possibles de ces différences. Ces dernières n’affectent pas les schémas de variabilité saisonnière et annuelle observés à grande échelle. L’Alaska est divisé en zones intérieures et zones côtières, possédant une variabilité constante mais différente, séparées par une région de transition. Celle-ci possède une grande variabilité interannuelle mais une faible variabilité à long terme de la moyenne. Les deux jeux de données sont compatibles avec les quatre grands écosystèmes et leurs zones de transition que nous avions identifiés dans nos travaux antérieurs. Il y a cependant des différences à l’échelle régionale entre les deux ensembles de cartes; elles témoignent de différences dans les domaines physiographiques et dans le traitement que font les deux groupes (AGDC et SCAS) de ces domaines. Ces différences offrent également une piste pour l’établissement d’un réseau d’observation amélioré pour l’Alaska. En nous basant sur une validation fondée sur des données indépendantes recueillies in situ, nous concluons que le jeu de données produit par SCAS représente actuellement la meilleure couverture spatiale disponible pour les moyennes mensuelles à long terme des précipitations et des températures de l’air en surface en Alaska

Multifactorial QT interval prolongation

Acquired long QT interval has been widely reported to be a consequence of drug therapy and electrolyte disturbances. We describe two cases of multifactorial acquired QT interval prolongation and torsades de pointes. In the first case, the drugs venlafaxine, amiodarone and domperidone may have contributed to QT interval prolongation in a patient with hypokalemia and hypomagnesaemia. In the second case, QT interval prolongation occurred in a patient taking quetiapine and citalopram, and whose use of hydrocholorothiazide and history of chronic alcohol abuse likely contributed by rendering the patient hypokalemic. These cases highlight the potential risks associated with polypharmacy and demonstrate that though torsades de pointes is an uncommon arrhythmia, the combination of multiple factors known to prolong QT interval may precipitate this life-threatening arrhythmia. (Cardiol J 2010; 17, 2: 184-188

A Natural Plasmid Uniquely Encodes Two Biosynthetic Pathways Creating a Potent Anti-MRSA Antibiotic

Background Understanding how complex antibiotics are synthesised by their producer bacteria is essential for creation of new families of bioactive compounds. Thiomarinols, produced by marine bacteria belonging to the genus Pseudoalteromonas, are hybrids of two independently active species: the pseudomonic acid mixture, mupirocin, which is used clinically against MRSA, and the pyrrothine core of holomycin. Methodology/Principal Findings High throughput DNA sequencing of the complete genome of the producer bacterium revealed a novel 97 kb plasmid, pTML1, consisting almost entirely of two distinct gene clusters. Targeted gene knockouts confirmed the role of these clusters in biosynthesis of the two separate components, pseudomonic acid and the pyrrothine, and identified a putative amide synthetase that joins them together. Feeding mupirocin to a mutant unable to make the endogenous pseudomonic acid created a novel hybrid with the pyrrothine via “mutasynthesis” that allows inhibition of mupirocin-resistant isoleucyl-tRNA synthetase, the mupirocin target. A mutant defective in pyrrothine biosynthesis was also able to incorporate alternative amine substrates. Conclusions/Significance Plasmid pTML1 provides a paradigm for combining independent antibiotic biosynthetic pathways or using mutasynthesis to develop a new family of hybrid derivatives that may extend the effective use of mupirocin against MRSA

Interatrial block in patients with obstructive sleep apnea

Background: Obstructive sleep apnea (OSA) is a common disorder that affects 5% of the adult North American population. It is associated with atrial arrhythmias and stroke. The mechanisms of this association remain unclear. The aim to the study was to identify the factors associated with interatrial block (IAB) among patients with OSA. Methods: Patients referred for polysomnography were studied. Sleep apnea severity (apnea-hypopnea index [AHI]) was measured in each subject. 12-lead ECGs were scanned and amplified (× 10); P-wave duration and dispersion were measured using a semi-automatic caliper. IAB was defined as a P-wave duration &#8805; 120 ms. Results: Data from 180 consecutive patients was examined. Moderate-severe OSA (mean AHI = 56.2 &#177; 27.9) was present in 144 (OSA group). The remaining 36 had mild or no OSA (mean AHI = 5.6 &#177; 3.6) and were used as controls. Age distribution between the groups did not differ and there were more males in the OSA group (69.4% vs 47.2%, p = 0.01). Obesity (78.5% vs 39.4%, p < 0.001) and hypertension (51.4% vs 27.8%, p < 0.01) were more prevalent in the OSA group. IAB was more prevalent in patients with moderate-severe OSA (34.7% OSA vs 0% controls, p 30 were independent predictors of maximum P-wave duration (p = 0.001 and p < 0.001, respectively). P-wave dispersion was significantly higher in the severe OSA group (14.6 &#177; 7.5 for OSA, 8.9 &#177; 3.1 controls, p < 0.001). Conclusions: Older age and moderate-severe OSA are predictors of IAB. P-wave dispersion is increased in patients with moderate-severe OSA. This may partly explain the high prevalence of atrial arrhythmias in patients with OSA. (Cardiol J 2011; 18, 2: 171-175