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Biomedical subjects

A A Jones

Publications and source records attributed to A A Jones.

43 records · Page 3Linked to original sources
PubMed1980

Comparison of degrees of coronary arterial luminal narrowing determined by visual inspection of histologic sections under magnification among three independent observers and comparison to that obtained by video planimetry: an analysis of 559 five-millimeter segments of 61 coronary arteries from eleven patients.

The accuracy of determining degrees of luminal narrowing of 559 histologic sections from 61 human coronary arteries was evaluated by visual inspection under magnification (light microscopy) by three independent observers, and the results were compared to those obtained by video planimetry. With the per cent of cross-sectional area narrowing divided into four categories (0 to 25, 26 to 50, 51 to 75, and 76 to 100), both the extent of agreement between each independent observer and video planimetry, i.e., the accuracy of visual inspection under magnification and the extent of agreement among the independent observers, interobserver agreement, evaluated by the Kappa (K) statistic, were excellent. With a K value of 50 per cent indicating reasonably good agreement and values of greater than or equal to 70 per cent indicating strong agreement, the K values between the results of light microscopy and video planimetry by three observers were 61, 67, and 75 percent, respectively, and the extent of interobserver agreement was 72 per cent.

Arteriosclerosis↗
PubMed1979

Sucking action of the left ventricle: demonstration of a physiologic principle by a gunshot wound penetrating only the right side of the heart.

This report describes a man who died after a gunshot wound that entered the right atrium and exited from the right ventricle without entering the cardiac septa or the left side of the heart. At necropsy, the left atrial appendage was found to be inverted and invaginated into the mitral orifice. The invagination of the left atrial appendage is viewed as anatomic evidence that a negative left ventricular pressure was created as the left ventricular volume rapidly decreased as a result of right-sided cardiac exsanguination. Previously reported experiments in animals demonstrating the sucking (negative pressure) action of the left ventricle during ventricular diastole are summarized. The prerequisite for creation of a negative pressure in the ventricles during diastole is an extreme diminution in left ventricular volume, in this case as a result of right-sided cardiac bleeding. Only a vacuum effect of the left ventricle during diastole can explain the inversion and invagination of the left atrial appendage in this patient.

Adult↗
PubMed1979

Quantitation of coronary arterial narrowing at necropsy in sudden coronary death: analysis of 31 patients and comparison with 25 control subjects.

A quantitative analysis of the degree and extent of coronary arterial narrowing by atherosclerotic plaques in the entire lengths of each of the four major coronary arteries in a group of patients dying suddenly from coronary heart disease ("sudden coronary death") is described at necropsy. Cross sections were examined histologically in a total of 1,564 five mm long segments of the left main, left anterior descending left circumflex and right coronary arteries in 31 patients with sudden coronary death, and the observations were compared with those from examination of 1,100 five mm segments of the major epicardial coronary arteries in 25 control subjects. An average of 25 cm (50 five mm segments) of coronary artery were examined from each patient and an average of 22 cm (44 five mm segments) from each control subject. Of the 1,564 five mm segments examined in the 31 study patients, 557 (36 percent) were 76 to 100 percent narrowed in cross-sectional area by atherosclerotic plaques (control subjects 3 percent), 536 (34 percent) were 51 to 75 percent narrowed (control subjects 22 percent), 360 (23 percent) were 26 to 50 percent narrowed (control subjects 42 percent) and only 111 segments (7 percent) had 25 percent or less narrowing (control subjects 33 percent). The amount of severe (greater than 75 percent) narrowing of the right, left anterior descending and left circumflex coronary arteries was similar. Additionally, the amount of severe (greater than 75 percent) narrowing in the distal one half of the right, left anterior descending and left circumflex coronary arteries was similar to that in the proximal halves of these three arteries. The number of 5 mm coronary arterial segments narrowed 76 to 100 percent in cross-sectional area in the 31 study patients was not affected by the patient's age of death, sex, presence or absence of previous angina pectoris or myocardial infarction or the weight of the heart.

Adult↗
PubMed1977

A hitherto undescribed cause of prosthetic mitral valve obstruction.

A case is described in which severe prosthetic mitral valve obstruction was produced by entanglement of sutures across the central axis of the prosthesis on its ventricular side. The entangled sutures prevented the tilting disc occluder from falling into the left ventricular cavity during ventricular diastole.

Adult↗
PubMedDate not supplied

Radiographic analysis of regenerated bone around endosseous implants in the canine using recombinant human bone morphogenetic protein-2.

Ideal endosseous implant placement involves a congruent bony housing in close apposition to the implant surface. Clinical situations are encountered, however, in which the entire implant surface cannot be in close apposition to bone. In these instances, bone grafting materials are generally used to regenerate bone around the implant. In this study, a biologically active bone differentiation factor, recombinant human bone morphogenetic protein-2 (rhBMP-2), was used with two different carriers to regenerate bone around implants in standardized critical-sized defects in the canine mandible. Half of the sites had a nonresorbable membrane placed over the defect. Longitudinal standardized radiographs were obtained to assess the amount of bone regeneration on the mesial and distal of the implants after 4 and 12 weeks of healing. Ninety-six implants were placed in 12 fox-hounds. Bone fill was determined by linear measurement of bone on the radiographs, and changes in bone density were evaluated by computer-assisted densitometric image analysis of discrete areas adjacent to the implant. After 4 weeks of healing, nonmembrane sites had significantly greater bone height than membrane-protected sites. Following 12 weeks of healing, sites treated with rhBMP-2 had significantly greater bone formation than untreated sites. Sites treated with rhBMP-2 and a membrane had the greatest bone fill, followed by sites treated with rhBMP-2 but no membrane. Sites without rhBMP-2, whether with or without a membrane, had less bone fill than sites with rhBMP-2. At 12 weeks, sites with a membrane resulted in significantly more gain in bone density than sites without a membrane. Furthermore, sites treated with a collagen carrier resulted in greater gains in bone density than sites treated with a polylactide/glycolide carrier. The results from this study demonstrate by radiographic evidence that new bone formation in critical-sized defects around implants is dependent on time after defect treatment, the type of carrier used, the use of a barrier membrane, and the presence of rhBMP-2. In addition, these findings suggest that rhBMP-2, a bone differentiation factor, can significantly stimulate bone formation around endosseous dental implants.

Analysis of Variance↗