Myocardial Bridges and their Relationship to the Anterior Interventricular Branch of the Left Coronary Artery

OBJECTIVE: To analyze the relationship between myocardial bridges and the anterior interventricular branch (anterior descending) of the left coronary artery. METHODS: The study was carried out with postmortem material, and methods of dissection and observation were used. We assessed the perimeter of the anterior interventricular branch of the left coronary artery using a pachymeter, calculated its proximal and distal diameters in relation to the myocardial bridge, and also its diameter under the myocardial bridge in 30 hearts. We also observed the position of the myocardial bridge in relation to the origin of the anterior interventricular branch. RESULTS: The diameters of the anterior interventricular branch were as follows: the mean proximal diameter was 2.76±0.76 mm; the mean diameter under the myocardial bridge was 2.08±0.54 mm; and the mean distal diameter was 1.98±0.59 mm. In 33.33% (10/30) of the cases, the diameter of the anterior interventricular branch under the myocardial bridge was lower than the diameter of the anterior interventricular branch distal to the myocardial bridge. In 3.33% (1/30) of the cases, an atherosclerotic plaque was found in the segment under the myocardial bridge. The myocardial bridge was located in the middle third of the anterior interventricular branch in 86.66% (26/30) of the cases. CONCLUSION: Myocardial bridges are more frequently found in the middle third of the anterior interventricular branch of the left coronary artery. The diameter of the anterior interventricular branch of the left coronary artery under the myocardial bridge may be smaller than after the bridge. Myocardial bridges may not provide protection against the formation of atherosclerotic plaque inside the anterior interventricular branch of the left coronary artery.

Percutaneous implantation of endoprostheses in the carotid arteries

OBJECTIVE: To assess the in-hospital evolution of patients undergoing percutaneous stent placement in the carotid arteries. METHODS: From August 1996 to April 2001, we studied 86 patients with carotid arterial obliterative lesions > 70% who were treated with percutaneous stent placement in the carotid arteries. We assessed the rate of success of the implantation and of the procedure, the types of stents used, mortality rate, and neurological complications. RESULTS: Successful implantation was obtained in 98.9% of the cases, and the procedure was successful in 91.8%. The Wallstent was the most frequently used stent (73 patients - 77%). Cerebral strokes occurred as follows: 3 (3.2%) transient ischemic attacks, 1 (1.1%) minor stroke, and 3 (3.1%) major strokes. One (1.1%) patient died during hospitalization. CONCLUSION: The high rate of success of stent implantation (98.9%) in addition to the low rate of cerebral stroke/death (4.2%) showed the efficiency and safety of percutaneous stent placement in carotid arteries.

Endothelium-dependent relaxation in response to poly-L-arginine in canine coronary arteries: implications about hyperpolarization as a mechanism of vasodilatation

OBJECTIVE: To study the mechanism by which poly-L-arginine mediates endothelium-dependent relaxation. METHODS: Vascular segments with and without endothelium were suspended in organ chambers filled with control solution maintained at 37ºC and bubbled with 95% O2 / 5% CO2. Used drugs: indomethacin, acetycholine, EGTA, glybenclamide, ouabain, poly-L-arginine, methylene blue, N G-nitro-L-arginine, and verapamil and N G-monomethyl-L-arginine. Prostaglandin F2á and potassium chloride were used to contract the vascular rings. RESULTS: Poly-L-arginine (10-11 to 10-7 M) induced concentration-dependent relaxation in coronary artery segments with endothelium. The relaxation to poly-L-arginine was attenuated by ouabain, but was unaffected by glybenclamide. L-NOARG and oxyhemoglobin caused attenuation, but did not abolish this relaxation. Also, the relaxations was unaffected by methylene blue, verapamil, or the presence of a calcium-free bathing medium. The endothelium-dependent to poly-L-arginine relaxation was abolished only in vessels contracted with potassium chloride (40 mM) in the presence of L-NOARG and indomethacin. CONCLUSION: These experiments indicate that poly-L-arginine induces relaxation independent of nitric oxide.

The beginnings of life: being some account of the nature, modes of origin and transformation of lower organisms. By H. Charlton Bastian.

1

Anatomy at a Glance

The study of anatomy has changed enormously in the last few decades. No longer do medical students have to spend long hours in the dissecting room searching fruitlessly for the otic ganglion or tracing the small arteries that form the anastomosis round the elbow joint. They now need to know only the basic essentials of anatomy with particular emphasis on their clinical relevance and this is a change that is long overdue. However, students still have examinations to pass and in this book the authors, a surgeon and an anatomist, have tried to provide a means of rapid revision without any frills. To this end, the book follows the standard format of the at a Glance series and is arranged in short, easily digested chapters, written largely in note form, with the appropriate illustrations on the facing page. Where necessary, clinical applications are included in italics and there are a number of clinical illustrations. We thus hope that this book will be helpful in revising and consolidating the knowledge that has been gained from the dissecting room and from more detailed and explanatory textbooks.

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

Background: Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. Objective: To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. Methods: This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. Results: The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). Conclusion: In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure related to the carotid functional measure. The carotid artery structure was directly related to aortic stiffness, which was inversely related to the carotid artery functional property.

Smoothing singularities of Riemannian metrics while preserving lower curvature bounds

Magdeburg, Univ., Fak. für Mathematik, Diss., 2014

Descriptions of apparently new species and subspecies of mammals from California, Oregon, the Kenai peninsula, Alaska, and Lower California, Mexico, by D. G. Elliot.

v.3:no.10(1903)

An annotated list of a collection of reptiles from southern and northern Lower California.

v.7:no.1(1905)

Some lower Huronian stromatolites of northern Michigan / Eugene S. Richardson, Jr. --

v.10:no.8(1949)