Secondary structure of the Tetrahymena ribosomal RNA intervening sequence: structural homology with fungal mitochondrial intervening sequences.

Splicing of the ribosomal RNA precursor of Tetrahymena is an autocatalytic reaction, requiring no enzyme or other protein in vitro. The structure of the intervening sequence (IVS) appears to direct the cleavage/ligation reactions involved in pre-rRNA splicing and IVS cyclization. We have probed this structure by treating the linear excised IVS RNA under nondenaturing conditions with various single- and double-strand-specific nucleases and then mapping the cleavage sites by using sequencing gel electrophoresis. A computer program was then used to predict the lowest-free-energy secondary structure consistent with the nuclease cleavage data. The resulting structure is appealing in that the ends of the IVS are in proximity; thus, the IVS can help align the adjacent coding regions (exons) for ligation, and IVS cyclization can occur. The Tetrahymena IVS has several sequences in common with those of fungal mitochondrial mRNA and rRNA IVSs, sequences that by genetic analysis are known to be important cis-acting elements for splicing of the mitochondrial RNAs. In the predicted structure of the Tetrahymena IVS, these sequences interact in a pairwise manner similar to that postulated for the mitochondrial IVSs. These findings suggest a common origin of some nuclear and mitochondrial introns and common elements in the mechanism of their splicing.     

La santé des pasteurs mobiles au Sahel – Bilan de 15 années de recherches et développement

Dans le Sahel, entre la Mauritanie et la Somalie incluant le Nord Kenya, environ 20 à 30 millions de personnes vivent en transhumance. Le rythme de leur migration suit l’évolution saisonnière du climat et la disponibilité des ressources, telle que l'eau, le pâturage et le sel. Malgré une exposition élevée à certaines maladies comme les zoonoses et les problèmes conditionnés liés au climat, les pasteurs mobiles sont parmi les populations quasiment exclues du système de santé, car la mise à disposition des services sociaux adaptés à un mode de vie mobile est difficile. Suivant l'objectif de recherche d'un meilleur accès aux soins des pasteurs mobiles, l'Institut Tropical et de Santé Publique Suisse, en partenariat avec plusieurs institutions dans la région, est actif au Sahel depuis 15 ans, aussi bien dans le domaine de la recherche, que celui des actions de développement. Basées sur une approche orientée vers les besoins des pasteurs mobiles pour leur développement, des recherches interdisciplinaires ont contribué à mieux comprendre la situation et les problèmes des éleveurs. En relation de la proximité entre l'homme et son bétail, une approche unissant la santé humaine et animale s'est avérée bonne et la valeur ajoutée d'une meilleure collaboration entre médecine humaine, animale et l'environnement a été démontrée. Ces approches utiles devraient être poursuivies et consolidées dans les recherches et le développement des actions futurs.     

Trends in Hypertension Prevalence,Awareness, Treatment,and Control Among US Adults 80 Years and Older, 1988–2010

The authors examined trends in systolic blood pressure (SBP) and diastolic blood pressure (DBP) and the prevalence, awareness, treatment, and control of hypertension in 1988–1994 (n=1164), 1999–2004 (n=1,026), and 2005–2010 (n=1048) among US adults 80 years and older in serial National Health and Nutrition Examination Surveys. Hypertension was defined as SBP ≥140 mm Hg, DBP ≥90 mm Hg, or use of antihypertensive medication. Awareness and treatment were defined by self‐report and control as SBP/DBP<140/90 mm Hg. Mean SBP decreased from 147.3 mm Hg to 140.1 mm Hg and mean DBP from 70.2 mm Hg to 59.4 mm Hg between 1988–1994 and 2005–2010. The prevalence, awareness, and treatment of hypertension each increased over time. Controlled hypertension increased from 30.4% in 1988–1994 to 53.1% in 2005–2010. The proportion of patients taking 3 classes of antihypertensive medication increased from 7.0% to 30.9% between 1988–1994 and 2005–2010. Increases in awareness, treatment, and control of hypertension and antihypertensive polypharmacy have been observed among very old US adults.

The US population is aging and it is projected that the number of US adults 80 years and older will triple by 2050.¹ Hypertension is one of the most important risk factors for coronary heart disease, stroke, and heart failure, each of which has a high incidence in the very old patients.², ³, ⁴ A meta‐analysis of randomized trials that included participants 80 years and older found antihypertensive treatment to be associated with a reduced risk for stroke, cardiovascular events, and heart failure.⁵ Multi‐morbidity and functional impairment are common among the very old and the applicability of antihypertensive treatment trial results to this population has been questioned.⁶, ⁷, ⁸, ⁹ A major concern in using antihypertensive medications in the very old is the potential increased risk for adverse events including falls and myocardial infarction associated with low blood pressure (BP).¹⁰, ¹¹, ¹² Providers must often weigh potential cardiovascular benefits against the perceived risks of pharmacologic BP‐lowering among the very old. For these reasons, treatment patterns may be different for the very old vs the general US population.Given the anticipated growth of the very old population in the United States, there is a need to document the prevalence of hypertension and BP treatment patterns in this population. Such information could be used to guide the development and implementation of approaches for improving BP management in this group. Therefore, we examined secular changes in SBP and DBP and hypertension prevalence, awareness, treatment, and control from 1988–1994 through 2005–2010 among representative samples of US adults aged 80 and older. In addition, we examined trends in the use of different classes of antihypertensive medications and the prevalence of antihypertensive polypharmacy among very old US adults.     

Prevalence of dental caries among children in a rural Tanzanian community

The age specific prevalences of mixed caries were determined in 346 children aged 1 to 15 years in a rural community in Morogoro Region, south-eastern Tanzania. In primary dentition 58.9% of children were caries free while dmf index averages 1.08. In permanent dentition 74.3% were caries free while DMF index averaged 0.43. Permanent dentition showed a constant increase in caries prevalence with age such that over half of 15 year old children had caries experience with a DMF index of 1.2. This relatively low prevalence of caries is associated with low consumption of refined sugars. Recommendations are made to support preventive dental health services and programmes in primary schools and maternal and child health clinics.     

A study of the bacteria associated with advancing periodontitis in man

Samples of apical plaque were taken by means of an anaerobic gas-flushed syringe from 21 sites in eight patients. The samples were anaerobically dispersed, diluted and plated and incubated in an atmosphere of 80% N2, 10% H2 and 10% CO2 for 7-21 days. All colonies on plates containing 20-50 isolates were picked, repeatedly restreaked, characterized and identified where possible by a probabilistic computer identification program. The sites were divided into four groups on the basis of clinical features. The significance of differences between bacterial populations in the groups was determined by the Kruskal Wallis and Mann-Whitney U tests, while the Spearman rank correlation coefficient was used to determine the rank correlation of clinical features of diseases and microbial species. The subgingival microbiota in advanced destructive sites was predominated by Gram-negative rods. The microbiota of two young adult patients with generalized extensive bone loss, extensive clinical inflammation and suppuration was dominated by Bacteroides asaccharolyticus and an organism with characteristics consistent with Actinobacillus actinomycetemcomitans. The predominant cultivable microbiota in two patients with extensive bone loss but minimal clinical inflammation was predominated by Bacteroides melaninogenicus ss intermedius and Eikenella corrodens in one patient and E. corrodens and a slow growing fusiform-shaped Bacteroides in a second patient. A third group of four patients demonstrated moderate levels of clinical inflammation and evidence of continued bone loss in the last year. Predominant organisms in this group were more heterogeneous and included B. asaccharolyticus, Fusobacterium nucleatum, the "fusiform" Bacteroides and anaerobic vibrios. Sites with minimal disease in the patients revealed higher proportions of Gram-positive organisms including Rothia dentocariosa, Actinomyces naeslundii and Actinomyces viscosus. A positive rank correlation could be detected between clinical inflammation including suppuration and B. asaccharolyticus and a negative rank correlation between inflammation and E. corrodens.     

Prosthetic reconstruction of a patient with an irradiated total rhinectomy with navigated surgical placement of a single zygomatic implant: A clinical report

This clinical report details the rehabilitation of a patient who underwent a total rhinectomy, subsequent adjuvant radiation therapy, and eventual prosthetic rehabilitation but then developed an empirically diagnosed medical adhesive intolerance. With the aid of digital planning and real time navigation, 2 zygomatic implants were placed by using a flapless surgical approach followed by early delivery of an interim prosthesis. In spite of the failure of 1 craniofacial implant, definitive restoration was accomplished by using a titanium bar, double magnetic attachments, and a new silicone prosthesis.