Search PubMed⌕ Search

Biomedical subjects

K W Marck

Publications and source records attributed to K W Marck.

41 records · Page 3Linked to original sources
PubMed1982

Lung transplantation in the rat: I. Technique and survival.

For immunogenetic and economical reasons, an operative technique for lung transplantation in the rat was developed. With the use of an operation microscope and 8-0, 9-0, and 10-0 sutures, the left pulmonary artery, vein, and brochus were anastomosed. The mean operation time was 4 hours; the mean graft ischemia time, 87 minutes. After frequent failures initially, due to anesthetic problems and lack of experience with microsurgical operative technique, a final peroperative survival of about 80% was obtained. Postoperative mortality approximated 50%. The main cause of postoperative death was thrombus formation at the site of an anastomosis. In a final series of 28 isogeneic transplantations, proper data for a one-month follow-up was obtained from 36% of the animals that underwent operation, a percentage comparable with initial canine pulmonary and rat renal transplantation studies. Left lung transplantation in the rat proved to be technically feasible and may provide an immunogenetically well defined and economically advantageous animal model in lung transplantation research.

Animals↗
PubMed1982

Lung transplantation in the rat: II. lung perfusion scintigraphy in normal and left lung-transplanted rats.

Lung perfusion scintigraphy with technetium 99m-labeled microspheres was performed in a series of 14 normal rats. The mean value of left lung perfusion was 36.9 +/- 4.9% of total lung perfusion. Duplicate determinations on three possible error levels were evaluated statistically: (1) separation of the lung fields on the computer scintigram, (2) positioning of the animal under the gamma camera, and (3) measurement after a one-week interval. The determinations resulted in standard deviations of (1) 2.8%, (2) 0, and (3) 1.4%, respectively. These results are comparable with those of lung perfusion studies in dogs. Lung perfusion scintigraphy, chest roentgenography, and postmortem examination were used in the functional evaluation of two groups of left lung-transplanted rats: Group A (n = 12) had short-term follow-up and Group B (n = 11) had long-term follow-up. A common finding in Group A was a subnormally perfused and aerated graft, showing normal lung tissue for the most part at postmortem examination. In Group B, grafts were rarely perfused and aerated. At postmortem examination, they were fibrotic or abscessed, possibly due to chronic rejection. A good correlation was found between perfusion scintigraphy, chest roentgenography, and postmortem findings.

Animals↗
PubMed1982

A comparison of angiography with oculopneumoplethysmography in carotid artery disease.

Oculopneumoplethysmography (OPPG) is a non-invasive method for the detection of carotid artery disease. In order to evaluate this method an OPPG test was performed routinely on 220 patients who were suspected of cerebrovascular disease. Sixty of these patients, selected on clinical grounds, also underwent angiography and our report deals with this group of patients. They were subdivided in the light of the angiographic findings and the results of the OPPG tests were compared with those of angiography. In 13 patients with a normal angiogram all but one had a normal OPPG test, indicating a specificity of 93%. Three out of 12 patients with a stenosis of less than 60% had an abnormal OPPG test, reflecting hemodynamic alterations in arteries, shown as mildly stenotic by angiography. Thirty-two out of 35 patients with a stenosis of at least 60% or actual occlusion had an abnormal OPPG test indicating a sensitivity of 91%, which increased to 97% with inclusion of carotid compression findings. The hemodynamic significance of the deviating tests in the latter two groups is discussed. OPPG is an easy and simple method of complementing angiography with hemodynamic data in patients with transient ischemic attacks (TIA's) and cerebrovascular accidents (CVA's). It can also be used to screen patients with asymptomatic bruits or vague neurologic complaints, prior to vascular surgery and to follow patients up after carotid endarterectomy.

Angiography↗
PubMed1977

Biodegradability and tissue reaction of random copolymers of L-leucine, L-aspartic acid, and L-aspartic acid esters.

A series of copoly(alpha-amino acids) with varying percentages of hydrophilic (L-aspartic acid) and hydrophobic monomers (L-leucine, beta-methyl-L-aspartate, and beta-benzyl-L-aspartate) were implanted subcutaneously in rats and the macroscopic degradation behavior was studied. Three groups of materials (A,B,C) with different ranges of hydrophilicity were distinguished: A) hydrophobic materials showed no degradation after 12 weeks; B) more hydrophilic materials revealed a gradual reduction in size of the samples, but were still present after 12 weeks; and C) hydrophilic copolymers disappeared within 24 hr. The tissue reactions caused by the materials of group A resembled that of silicone rubber, whereas those of group B showed a more cellular reaction.

Animals↗