Arterial vascularization of the human moderator band: an analysis of this structure's role as a collateral circulation route

In the human heart, the moderator band, or trabecula septomarginalis, is a muscle column that courses inferiorly from the right portion of the interventricular septum to the base of the anterior papillary muscle of the right ventricle This muscular structure is crossed by one or more arteries, which come from the anterior interventricular artery and perfuses the anterior papillary muscle of the right ventricle. In order to clarify the arterial supply of this muscle column, we studied 28 adult hearts, free of any signs of coronary disorder. The path of the moderator band artery was followed by means of microdissection, and we studied the source, course, and interconnections made with other arteries. We observed that the source of the moderator band artery lies in the first three anterior septal arteries, most often in the second one. In relation to the short axis of the heart, the artery of the moderator band can either follow a horizontal path to the septal papillary muscle of the right ventricle or an oblique route to the moderator band, depending on the position of its source. In all the hearts studied, the moderator band artery made anastomotic connections at the base of the anterior papillary muscle of the right ventricle with various branches of the right coronary artery, which means that it can play a key role in collateral circulation following obstruction of the epicardium coronary arteries.     

A comparative study of three new occlusive dressings for healing of graft donor sites versus conventional therapy

Summary A comparative study of four skin graft donor site dressings was undertaken. This was a prospective and cross-over study of 25 consecutive patients with burns up to 40% TBSA treated with split skin grafts. Each donor site was divided into four sections and covered with different dressings in order to evaluate their effectiveness in healing, the time required for complete epithelialization, patient acceptance and any intolerance or local infection. The results showed that the occlusive hydrocolloid dressing significantly decreases (p<0.01) the mean time required for complete healing (7.45 days) compared with a semiocclusive hydrocolloid (10.29 days), a polyurethane sheet (9.4 days) and the conventional dressing (10.04 days).Presented at the IV European Burns Congress in Barcelona, Spain, September 25, 1991 (Abstract No. 117)     

Patterns of the coronary artery irrigation in the left ventricle

Summary Nowadays, the classifications of coronary arterial preponderance (Schlesinger, Baroldi, Gensini) do not provide the necessary information for a good systematization of coronary arterial irrigation. Based on segmental analysis (Selvester's method) an alternative classification of the arterial distribution of the left ventricle is presented. One thousand eighty ventricle segments corresponding to 90 human hearts (age range from 4 days to 94 years) are studied, using microdissection techniques. In order to obtain segmental arterial patterns, a cluster analysis was used. The alternative classification is based on the predominance of the segments irrigated by: the anterior interventricular artery (Type I; 31% of cases), the circumflex artery (Type II; 37% of cases), or a balance between both arteries (Type III; 32% of cases). Each group can be divided into two subgroups (A and B), according to the existence or not of a balance between the territories of anterior interventricular and circumflex arteries. This classification allows as a more realistic approach to the subject of arterial dominance, given that the left ventricle always presents a predominant irrigation from the anterior interventricular, the circumflex or both arteries.

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Essai de classification de l'irrigation artérielle coronaire du ventricule gauche

Résumé La classification en dominance artérielle coronaire, actuellement utilisée (Schlesinger, Baroldi, Gensini) ne donne pas toutes les informations nécessaires à une bonne systématisation de la distribution des artères coronaires. Nous présentons ici une classification alternative, basée sur la segmentation des parois du ventricule gauche à la manière de Selvester. 1080 segments ventriculaires gauches de 90 coeurs humains prélevés sur des sujets de 4 jours à 94 ans ont été analysés en utilisant les techniques de microdissection. La présente classification est basée sur — la prédominance de segments irrigués par l'artère interventriculaire antérieure (IVA) : type I, par l'artère circonflexe (CX) : type II, — ou sur l'existence d'un équilibre entre ces deux artères : type III. Le pourcentage de distribution de ces groupes est le suivant : type I : 31 % ; type II : 37 % ; type III : 32 %. Chacun de ces groupes peut-être divisé en deux sous-groupes A et B selon — la prédominance du nombre de segments irrigués exclusivement ou en partage par l'IVA, — ou l'existence d'un équilibre entre l'IVA et la CX. Cette classification permet une approche plus réaliste du problème de dominance artérielle, étant donné que le ventricule gauche est toujours irrigué en prédominance par l'IVA, par la CX ou à la fois par les deux.

     

Microstructure and Mechanical Behavior of Porous Ti–6Al–4V Processed by Spherical Powder Sintering

Reducing the stiffness of titanium is an important issue to improve the behavior of this material when working together with bone, which can be achieved by generating a porous structure. The aim of this research was to analyze the porosity and mechanical behavior of Ti–6Al–4V porous samples developed by spherical powder sintering. Four different microsphere sizes were sintered at temperatures ranging from 1300 to 1400 °C for 2, 4 and 8 h. An open, interconnected porosity was obtained, with mean pore sizes ranging from 54.6 to 140 µm. The stiffness of the samples diminished by as much as 40% when compared to that of solid material and the mechanical properties were affected mainly by powder particles size. Bending strengths ranging from 48 to 320 MPa and compressive strengths from 51 to 255 MPa were obtained.     

The National Health Service Corps for the 21st century

The National Health Service Corps (NHSC) was created in 1970 to provide primary health care clinicians for the underserved. The article includes a review of the peer-reviewed and intragovernmental literature on the NHSC program from 1971 to 1998 and also presents a current profile of the program. Despite significant increases in NHSC field strength since 1991, the 2,439 clinicians meet only 12% of the need for primary health care providers in underserved areas. While the NHSC has successfully addressed clinician diversity and retention issues, community and site development remain barriers to increasing access. Most communities in need are not ready to recruit and support clinicians. The NHSC of the next millennium must work with the neediest communities to reach the appropriate stage of readiness. Only after completing the necessary "preplacement" activities can the NHSC assist in the recruitment and placement of clinicians to increase access.