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Biomedical subjects

D B Hackel

Publications and source records attributed to D B Hackel.

At least 73 records · Page 4Linked to original sources
PubMed1975

Comparison of angiographic and postmortem findings in patients with coronary artery disease.

The accuracy of coronary cineangiography in predicting the degree of stenosis in coronary arteries was evaluated by comparing autopsy and premortem cineangiographic findings in 25 patients. Coronary cineangiograms and autopsy specimens were reviewed independently by two cardiologists and two pathologists. Identical diagrams dividing the cononary arteries into 12 segments were used by both groups to record the location and degree of stenosis observed. Cineangiographic findings were in agreement with pathologic findings (less than 25 percent difference in cross-sectional luminal area) in 178 (79 percent) of the 226 segments examined, but overestimated the degree of stenosis in 13 (6 percent) and underestimated it in 34 (15 percent). Thus, cineangiography appears to be a reliable tool in evaluating coronary artery disease. When diagnostic errors are made, they are usually underestimations of the degree of disease; common causes of error are circumferential stenosis, eccentric lesions, obstruction of view by artifical valves and poor opacification due to severe proximal stenosis.

Autopsy↗
PubMed1975

Persistence of MB isoenzyme of creatine phosphokinase in the serum after minor iatrogenic cardiac trauma. Absence of postmortem evidence of myocardial infarction.

The specificity of serum CPK-MB for acute myocardial infarction was examined by retrospective analysis of 401 consecutive patients admitted to Coronary Care Unit over a three and one-half year period with suspected infarction in whom the isoenzyme was subsequently detected. Four patients (1 per cent) who died during the hospital admission had no autopsy evidence of acute myocardial infarction. All four had experienced mild iatrogenic cardiac trauma, following which serum CPK-MG persisted for at least 24 hours. In one patient, a permanent pacemaker had been inserted by the transmediastinal approach. Two patients had been subjected to closed chest cardiac massage and intracardiac puncture, and one to external cardiac massage alone. The findings suggest that persistent identification of serum CPK-MB, although specific for myocardial necrosis, cannot be regarded as diagnostic of myocardial infarction. The implications of this are important to treatment of patients after cardiopulmonary resuscitation and operative trauma to the heart.

Aged↗
PubMed1975

Ultrastructral effects of in virto experimentation on right ventricular papillary muscle from cats in hypovolemic shock (38487).

The present data demonstrate for the first time that repeated stimulation (2-3 hr in an oxygenated perfusate) of right ventricular papillary muscles from cats subjected to hypovolemic shock does not alter the ultrastructure of the shock lesions. Neither does the in vitro experimentation cause functional impairment as determined by the measured isometric twitch tension. The data also indicate that electron microscopy is important to the evaluation of papillary muscles from cats subjected to shock.

Animals↗
PubMed1975

Formation of myocardial zonal lesions.

Right ventricular papillary muscles from control cats and from cats subjected to hemorrhagic shock were studied by electron microscopy. Half of the muscles were fixed at the apex of their active length-tension curves following stimulation in a papillary muscle bath. The other half were also fixed under tension. The ultrastructure of each muscle was examined in detail. A series of stages in the formation of myocardial zonal lesions, ranging from minimal changes in the intercalated discs to severe lesions, were identified and interpreted as representing the sequential stages in the formation of zonal lesions. One of the earliest (least severe) changes in the formation of zonal lesions, the separations of actin filaments from the intercalated disc, may be critical to the subsequent development of cardiac failure in hypovolemic shock. Mitochondrial displacement was a late event in the formation of the lesions, occurring only after major alterations had taken place in the sarcomeres and intercalated discs. It was noted that the ultrastructure of mitochondria remained essentially normal, and that there was no cell swelling associated with zonal lesions. This serves as confirmatory evidence that myocardial zonal lesions are a unique form of myocyte injury, are potentially reversible, and are not caused by ischemia.

Actins↗
PubMed1973

Protein synthesis in pancreatic beta cells of the normal and diabetic Egyptian sand rat (Psammomys obesus). An autoradiographic study with the electron microscope.

The pattern of protein synthesis was studied in the pancreatic beta cells of the Egyptian sand rat (Psammomys obesus). When fed a standard Purina Laboratory Chow diet instead of a leafy vegetable diet, these animals develop the characteristic signs of diabetes mellitus. Tritiated leucine was injected intravenously into pairs of sand rats (one on a vegetable diet and one on a Purina Laboratory Chow diet). Two pairs of animals were sacrificed at 5-, 20- and 60-minute intervals, and pancreatic tissue was studied by electron microscopic autoradiography. At 5 minutes, the relative grain density was greatest over the rough endoplasmic reticulum; at 20 minutes it was greatest over the Golgi complex and at 60 minutes, over the granules. There were no statistically significant differences in the relative grain densities over the rough endoplasmic reticulum, over the Golgi complex or over the secretion granules between the sand rats on the vegetable diet and Chow diet. These results show that in the early phase of the development of diabetes mellitus, the pattern of protein synthesis in the beta cells of the normal and diabetic sand rat compares with that of other endocrine glands. The tritiated leucine was apparently incorporated into the newly synthesized secretory product in the rough endoplasmic reticulum during the first 5 minutes. The formed product migrated to the Golgi complex at 20 minutes, and at 1 hour was seen mainly over the light granules. In addition, there was no obvious difference in this pattern of protein synthesis between the normal and diabetic sand rats. This suggests that the secretory product, considered to be mainly insulin, is produced in the usual or in increased amounts, but it is not fully utilized by the diabetic animal and remains in circulation, thus increasing the plasma insulin level.

Animal Feed↗