Drug delivery systems: 3A. Role of polymers in drug delivery

At present, polymers represent a class of ubiquitous materials. They are being used for a multitude of purposes and the almost inexhaustible varieties of molecular architecture that macromolecular materials can possess provides the possibility for a myriad of applications. Because of the increased interest being shown in the macromolecules by the pharmaceutical industry for the fabrication of drug delivery systems, numerous polymers have been synthesized and successfully used in drug delivery devices. The necessary conditions for developing the concept of pharmaceutically applicable polymers depend upon delineating a detailed knowledge of the relationship between the structure and properties of polymer networks. A number of polymers have been studied systematically from this point of view and there is every indication that the systems described have the potential to become clinically valuable and therefore marketable drug delivery systems. The potential of these promising polymers is still far from being exhausted and there is a strong possibility that many important developments will be forthcoming in this field in the future. In the current review article, polymers for controlled release have been divided into four major categories: diffusion-controlled systems; chemically controlled systems; solvent-activated systems; and magnetically controlled systems. Polymers as drug carriers also have been divided into various subgroups: soluble, biodegradable, mucoadhesive and other polymeric systems. The latter group includes polymers containing pendant bioactive substituents, matrix systems, heparin-releasing polymers, ionic polymers, oligomers and miscellaneous. At an introductory and fundamental level, an overview of these polymers and the materials science for the design of drug delivery systems will be discussed.     

Management of psychopharmacologic agents in children and adolescents

This article summarizes the ways in which a clinician should think about medication use in children and describes practical usage of the most frequently used child psychopharmacologic agents.Leena Ranade, M.D., and Aftab Qadir, M.D., were Fellows in Child Psychiatry, State University of New York at Stony Brook at the time of writing this article.     

A meta-analysis of genome-wide linkage scans for hypertension: the National Heart,Lung and Blood Institute Family Blood Pressure Program

bACKGROUND: Four multicenter Networks (GenNet, GENOA, HyperGEN, SAPPHIRe) form the National Heart, Lung and Blood Institute Family Blood Pressure Program (FBPP), to search for hypertension/blood pressure (BP) genes. The networks used different family designs and targeted multiple ethnic groups, using standardized protocols and definitions. Linkage genome scans were done on samples within each network (N = 6245 relatives). METHODS: The evidence was synthesized using meta-analysis. RESULTS: Combining ethnic groups, no region reached LOD >2, but several small peaks were identified, including chromosome 2p where two other recent reports find hypertension linkage. CONCLUSIONS: No regions show uniformly large effects on BP/hypertension in all populations.     

Pattern of missing probes in rifampicin resistant TB by Xpert MTB/RIF assay at a tertiary care centre in Mumbai

Setting

Department of Microbiology.

Emergency department revisits for nontraumatic dental conditions in Massachusetts

BackgroundInadequate access to oral health care and palliative care provided in the emergency department (ED) creates a pattern of repeat nontraumatic dental condition (NTDC) ED visits. The authors examined NTDC ED revisits and assessed the determinants associated with these visits in Massachusetts.MethodsThe authors examined NTDC ED revisits in Massachusetts during 2013 using the Massachusetts All-Payer Claims Database. The authors report patient characteristics of those who made a single NTDC ED visit and of those who made NTDC ED revisits within 30 days of the index NTDC ED visit. The authors used a multilevel logistic regression model to examine the determinants associated with NTDC ED repeat visits.ResultsIn 2013, 21.5% of NTDC ED visits were revisits. Men from 26 through 35 years of age who were enrolled in Medicaid and who did not make an outpatient dental office visit within 30 days of the index NTDC ED visit had increased odds of repeat visits.ConclusionsThe sizable proportion of NTDC ED repeat visits indicates that certain patients in Massachusetts experience consistent and systematic barriers in accessing appropriate and timely oral health care.Practical ImplicationsPrioritizing young adults and Medicaid enrollees for ED diversion programs and setting up a formal referral process via connecting patients to dental offices and community health centers after an NTDC ED visit may reduce NTDC ED revisits and provide appropriate oral health care to these patients.     

Palmar Type of Median Artery as a Source of Superficial Palmar Arch: A Cadaveric Study with Its Clinical Significance

The superficial palmar arch (SPA) and its contributing arteries are highly variable. The palmar type of median artery (PMA) can be involved in the formation of the SPA by replacing the superficial palmar branch of the radial artery (RA) or the ulnar artery (UA). The present study was undertaken to investigate the presence of the PMA and its contribution in the formation of SPA in 42 cadavers (84 upper limbs) of Indian origin. When there was a PMA, its outer diameter was measured in the carpal tunnel. The PMA was found in 13 upper limbs (15.4%), and of these ten incidences (11.9%), the PMA took part in the formation of SPA, and in three instances (3.5%), the PMA did not make up part of the SPA. Out of the ten cases in which the PMA contributed to the formation of SPA, in six cases (7.1%), the PMA anastomosed with the UA; in three cases (3.5%), the PMA anastomosed with both the UA and the RA, and in one incidence (1.1%), the PMA joined the arteria radialis indicis (deep branch of the RA) to complete the SPA. The outer diameters of the median arteries varied between 0.8 and 2.6 mm with the mean value of 1.7 mm. The present study concludes that the median–ulnar type of SPA was the most common type of SPA when the PMA was encountered as a source of superficial arterial arcade of the hand, followed by the radial–median–ulnar type. The vascular patterns found in this study are important to hand surgeons. The present study of PMA origin, course, and its contribution to the SPA will add to the existing knowledge of the vascular anatomy of forearm and hand.