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Biomedical subjects

M Lipton

Publications and source records attributed to M Lipton.

At least 37 records · Page 2Linked to original sources
PubMed1983

Evaluation of the post-coronary artery bypass patient by myocardial perfusion scintigraphy and computed tomography.

The clinical utility of 201Tl scintigraphy and of computed tomography for the noninvasive assessment of graft patency and regional myocardial perfusion was evaluated in 24 patients who had undergone aortocoronary bypass surgery. Perfusion defects on 201Tl scintigraphy (reversible or new, fixed) correlated (100% sensitivity, 78% specificity) with occlusion or stenosis of a graft or significant new native vessel disease. Graft occlusion was accurately demonstrated by dynamic computed tomography (100% sensitivity, 96% specificity) but did not uniformly correlate with regional perfusion. Perfusion defects in the distribution of patent grafts resulted from progressive native vessel disease or graft stenosis without complete occlusion. The absence of exercise-induced perfusion defects in regions of occluded grafts was attributed to suboptimal exercise, collateralization, or noncritical native vessel stenosis. The two studies provide complementary anatomic and physiologic information in the evaluation of the postbypass patient.

Adult↗
PubMed1982

Progressive encephalopathy in children with chronic renal insufficiency in infancy.

A retrospective analysis of children with renal failure during the first year of life revealed that 20 of 23 patients developed profound neurologic abnormalities. The encephalopathy was characterized by developmental delay, microcephaly, hypotonia, seizures, dyskinesia, and EEG abnormalities. No patient had been dialyzed, and four had not received aluminum salts prior to the development of neurologic symptoms. Inadequate statural growth and poor nutrition were present in all patients. It is probable that infants with chronic renal insufficiency are more susceptible to the development of this syndrome than are older children or adults because of the significant growth and maturation of the brain that occurs during the first years of life.

Body Height↗
PubMed1981

Technical aspects and clinical applications of CT/X, a dynamic CT scanner.

CT/X is an X-ray computed tomographic scanner system designed for research in the clinical applications of rapid sequence scanning. The minimum scan time is 1.5 sec, and up to 18 images of the same cross section can be derived from scans taken over a 30 sec time interval. With this high image rate, the transit of a bolus of iodinated contrast medium can be followed through any cross section of the body. Rapid sequence scanning through a series of contiguous levels can also be performed, and 12 levels can be scanned in less than 50 sec. The short aggregate scan period minimizes the likelihood of interslice patient motion resulting in high quality multiplanar images. To fully exploit this capability, an imaging facility capable of reformatting axial transverse display data into a plane of arbitrary orientation has been incorporated into the system. A computer-electrocardiographic interface is also provided for use in retrospective cardiac gating. The capabilities of the scanner are illustrated with selective clinical studies.

Angiography↗
PubMed1981

Repair of dissection of the thoracic aorta. Evaluation of false lumen utilizing computed tomography.

During the period 1975 to 1980, 21 patients with thoracic aortic dissections underwent surgical treatment. The operative technique was resection and tube graft replacement of the segment of the aorta containing the entry point into the false channel. Eleven Type A and 10 Type B dissections were resected. The hospital survival rate was 95%. The single operative death occurred in a patient with an acute Type A dissection. Three patients had total resection of the dissected segment; three had clotted false lumina; five had distal anastomosis to true and false lamina; and 10 had distal anastomosis to the true lumen only, with proximal entry into the false lumen obliterated by incorporating both intimal and adventitial walls in a single suture line. The late survival rate was 95% (mean 32 months, range 8 to 63 months). No late ruptures occurred. Computed tomography (CT) with contrast enhancement was used to evaluate the aorta and any residual false lumen at follow-up. Seven of eight patients in whom obliteration was attempted and CT scans performed demonstrated persistence of false lumen perfusion; in six of the eight, preoperative angiograms were adequate for evaluation of false lumen runoff. Major vessels arose from the false lumen in all cases, except in the one patient in whom obliteration was later successful. This report demonstrates that there is persistence of false lumen perfusion in patients in whom obliteration is attempted, and the mechanism of this persistence is the presence of major vessel runoff. It suggests that the mechanism by which long-term survival is achieved is by resection of the segment of aorta containing the entry site, which is frequently the site of subsequent enlargement and rupture, rather than obliteration of the false channel.

Adult↗
PubMed1980

Operation for chronic constrictive pericarditis: Do the surgical approach and degree of pericardial resection influence the outcome significantly?

Our experience with 27 patients undergoing pericardiectomy at New York University Medical Center over the past 13 years has evolved a radical pericardiectomy operation suggesting that two traditional concepts are erroneous: (1) pericardiectomy limited to the anterior and lateral surfaces of the ventricles is an adequate operation and (2) delayed recovery is due to myocardial "atrophy" and not to inadequate operation. Radical pericardiectomy entails removal of virtually the entire parietal pericardium from all cardiac surfaces including that of both ventricles, the right atrium, and the venae cavae. Performed in 22 patients by dissecting a cleavage plane between the thickened parietal pericardium and underlying epicardium, all procedures were done through a sternotomy. Intraoperative monitoring of arterial pressure, cardiac output, and wedge pressure is essential because of displacement of the left ventricle. The left ventricle can be completely mobilized so that at the end of the operation the entire heart can be lifted upward and the course of the coronary sinus fully visualized. Intraoperative pressure measurements demonstrate that this radical resection immediately corrects hemodynamic abnormalities (elevated right atrial and ventricular end-diastolic pressures), as demonstrated in 10 patients. Most patients undergo massive diuresis (7 to 16 kg) within two weeks, with an uneventful recovery. These findings contrast markedly with early experiences using a conventional limited pericardiectomy.

Adolescent↗
PubMed1980

Actinomyces meyeri osteomyelitis: an unusual cause of chronic infection of the tibia.

A 50-year-old man had draining fistulas of the right tibula for 15 years. He had been previously treated with antibiotic therapy of an unknown nature and by 3 sequestrectomies spaced over the 15-year interval, without a cure having been achieved. Several anaerobic bacteria, including Actinomyces meyeri were isolated from the bone lesion. The involvement of an actinomycete in osteomyelitis of a long bone is a very rare occurrence. After an additional sequestrectomy and penicillin therapy of an appropriate nature, clinical remission was achieved for the first time in 15 years.

Actinomyces↗
PubMed1979

Articular cartilage preservation and storage. I. Application of tissue culture techniques to the storage of viable articular cartilage.

Articular cartilage slice explants were stored under various conditions, including freezing-thawing at various rates by using dimethyl sulfoxide (DMSO) as a cryoprotective agent, incubating in standard tissue culture medium (MEM Eagle:NCTC 135:15% fetal calf serum) in 5% CO2 and air at 4 degrees, 21 degrees, and 37 degrees C, and incubating in standard tissue culture medium containing 200 micrograms/ml alpha-tocopherol (vitamin E) at 37 degrees C after first ascertaining a dose-response curve of vitamin E. Results indicated that articular cartilage slice explants did not survive freezing or storage at 4 degrees and 21 degrees C as measured by 35S uptake. When stored at 37 degrees C in standard tissue culture in 5% CO2 and air, the slice explants remained viable for up to 60 days. The addition of alpha-tocopherol to the medium resulted in significantly less release of previously incorporated 35Sin stored cartilage slices and significantly less reduction of the amount of hexosamine present in the stored explants. alpha-Tocopherol in the medium also preserved safranin O staining. Thus, the application of tissue culture techniques to the storage of articular cartilage made it possible to preserve cartilage slice explants in a viable, biochemically "normal" state.

Animals↗
PubMed1978

A specific inhibitor of complement (C5)-derived chemotactic activity in serum from patients with systemic lupus erythematosus.

In the course of examining polymorphonuclear leukocyte (PMN) chemotaxis in patients with systemic lupus erythematosus (SLE), we have found a previously undescribed serum inhibitor of complement (C5)-derived chemotactic activity. Serum from a 25-yr-old Black female with untreated SLE, when activated with zymosan, failed completely to attract either her own or normal PMN. Incubation of normal PMN with the patient's serum did not affect their subsequent random motility or chemotactic response toward normal zymosan-treated serum (ZTS). The patient's serum, however, did inhibit the chemotactic activity of normal ZTS and of column-purified C5-derived peptide(s), but had no effect on the chemotactic activity of either the synthetic peptide, N-formylmethionyl leucyl-phenylalanine or a filtrate prepared from a culture of Escherichia coli (bacterial chemotactic factor). The inhibitory activity in the patient's serum resisted heating at 56 degrees C for 30 min and could be separated from C5-derived chemotactic activity in the patient's ZTS (or normal ZTS that had been incubated with the patient's serum) by chromatography on Sephadex G-75. Despite its effect on C5-derived chemotactic activity, the patient's serum did not influence two other C5-derived biologic activities: PMN lysosomal enzyme-releasing activity and PMN-aggregating activity. Chromatography of the patient's serum (65% ammonium sulfate pellet) on Sephadex G-200 yielded three distinct peaks of inhibitory activity. Two were heat labile and exhibited other properties of the previously described chemotactic factor inactivators of normal human serum. The third and most active peak, however, resisted heating at 56 degrees C for 30 min, eluted with an apparent mol wt of 50,000-60,000, and acted specifically on C5-derived chemotactic activity. This uniquely specific, heat-stable inhibitor of C5-derived chemotactic activity has been found thus far in serum from 4 of 11 patients with active SLE and may account, in part, for altered host defenses against infections caused by pyogenic microorganisms.

Adult↗
PubMed1977

Joint resurfacing in the rabbit using an autologous osteochondral graft.

In rabbits, joint resurfacing with autologous osteoarticular condylar grafts composed of the articular cartilage and subchondral bone (two to eight millimeters thick) from the lateral femoral condyles was investigated. By means of morphological, histochemical, autoradiographic, and biochemical studies, the grafts were compared with sham and normal controls. When adequately fixed, the grafts remained viable and functionally and structurally intact during the twelve months of the experiment. The subchondral bone underwent rapid replacement in less than six weeks without loss of its supportive function. Resurfacing of a joint using an osteochondral graft is feasible in rabbits.

Animals↗
PubMed1976

The posterior aortic wall echocardiogram. Its relationship to left atrial volume change.

The normal posterior aortic wall echocardiogram shows anterior motion during left ventricular systole and predominantly posterior motion in three phases during left ventricular diastole. In six patients undergoing simultaneous left atrial angiograms and posterior aortic wall echocardiograms, there was excellent correlation between the posterior aortic wall motion and the change in the left atrial angiographic area showing the value of the posterior aortic wall echocardiogram in describing the left atrial volume curve. Left atrial and left ventricular pressures were measured with manometer tip catheters and correlated with simultaneous posterior aortic wall and mitral valve echocardiograms in four patients with atrial septal defects. These echocardiographic, angiographic, and hemodynamic correlations, as well as other evidence reported in this paper suggest that a major portion of posterior aortic wall motion is related to left atrial events and describes the left atrial volume curve.

Adolescent↗