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Biomedical subjects

L Goldberg

Publications and source records attributed to L Goldberg.

At least 109 records · Page 6Linked to original sources
PubMed1983

Effect of healing on small internal diameter arterial graft compliance.

Porosity is an essential component for long term function of small internal diameter synthetic vascular prostheses. Theoretically, porosity is required for healing by providing a scaffold for ingrowth of periprosthetic tissues. Porosity may be required for transfer of fluids and ions in prostheses even if tissue ingrowth does not occur. Increased permeability of vascular grafts has been shown to enhance tissue incorporation. Implants with pore sizes greater than 10 microns but less than 45 microns become ingrown with fibrohistiocytic tissue and capillaries. Implants with pore sizes greater than 45 microns are ingrown with organized fibrous tissue and minimal histiocytic response. The phenomenon of differential ingrowth may have important functional significance. Prostheses which heal with organized fibrous tissue have the potential for long term contracture, strangulation of vascularity and calcification. Fibrohistiocytic tissue has low mechanical strength and does not appear to contract or calcify. Elastomeric microporous vascular prostheses which are minimally ingrown or ingrown with fibrohistiocytic tissue maintain compliance after months of implantation. This study was designated to determine the effects of healing on the compliance of small internal diameter vascular replacements and to correlate the compliance to patency rates.

Animals↗
PubMed1983

Neovascularity of a tracheal prosthesis/tissue complex.

Permanent bioincorporation of a microporous tracheal prosthesis will require a stable blood supply to connective tissue supporting an epithelial surface. In experience with over 80 tracheal implants in dogs, we have observed that end-on ingrowth and epithelialization does not occur in the absence of lateral ingrowth, epithelialization is marked by the appearance of a subepithelial network of vessels, and this process must be well advanced by 6 to 8 weeks for long-term stability. These observations were extended by using microangiography to delineate the blood supply of the prosthesis/tissue complex. Six implants of bioelectric polyurethane with 10% gentamicin (3 cm length, 2 cm diameter, 1 to 1.25 mm wall thickness, 60 to 120 mu micropore diameter) were interposed in the dog thoracic trachea and wrapped with an omental pedicle. The aorta was perfused with a barium suspension at elective sacrifice between 10 weeks and 21 months. Radiographs of specimens were correlated with bronchoscopic, gross, and histopathological findings. Neovascularity of the prosthesis/tissue complex can be described in three categories: outer capsule, prosthetic wall, and inner lining. Outer capsule vessels were oriented circumferentially immediately adjacent to the prosthetic wall. They resembled arteries up to 75 mu diameter on microscopy and appeared to develop from the omentum with connections developing to the bronchial circulation. Prosthetic wall vessels up to 75 mu with thin muscular walls were noted to traverse the porous prosthetic wall. The inner lining had a network of subepithelial vessels that connected to the lamina propria vasculature of the native trachea across the anastomoses with vessels up to 120 mu in diameter. We conclude that the omentum provides an immediate blood supply and a base for early connective tissue ingrowth. Epithelialization occurs as early as 3 weeks on the favorable bed, accompanied by vascular connections to the existing lamina propria tracheal vessels. This dual organization of blood supply with connections across the prosthetic wall is probably important to long-term stability of healing.

Animals↗
PubMed1982

Effect of suture technique on arterial anastomotic compliance.

To determine the immediate effect of running and interrupted suture on anastomotic compliance, catheters were positioned in both femoral arteries of ten dogs for pressure measurement and introduction of an electromagnetic rheoangiometry loop probe. Changes in the area of the loop allowed simultaneous determination of the static and pulsatile internal diameter of the vessel when the loop was in an externally induced magnetic field. After dynamic diameter compliance (Cd) of the undisturbed femoral arteries was obtained, they were exposed, stripped of their adventitia, and divided. They were subsequently anastomosed with 6-0 polypropylene suture using a running anastomosis for one femoral artery and an interrupted anastomosis for the other; Cd was then measured 1 cm proximal to the anastomoses, at the anastomoses, and 1 cm distal to the anastomoses. The Cd significantly decreased with both running and interrupted anastomoses; running anastomoses showed significantly greater decrease in compliance than did interrupted.

Animals↗
PubMed1982

Changes in EEG, blood levels, mood scales and performance scores during long term treatment with diazepam, phenobarbital or placebo in patients.

1. The patient population consisting of fifteen patients was divided into three groups, namely: diazepam group, phenobarbital group and placebo group. After three weeks the medicated groups were switched to placebo for a week and the placebo group was given phenobarbital. 2. The parameters to be assessed once a week comprised frequency-analyzed EEG recordings, performance in two attention tests and subjectively estimated mood modalities. 3. The EEG analysis suggested that EEG patterns: a) were drug-dependent, with a differential distribution for each drug of the four frequency bands analyzed; b) showed no change during the three-week treatment period; c) changed on cessation of medication or on switch from placebo to active medication; d) were task-dependent and changed in a systematic way with the level of activation (stress, vigilance or relaxation). 4. The results would allow a better understanding of the clinical course, the choice of therapeutic measures and of the underlying mechanisms of action.

Adult↗
PubMed1982

Severe exophthalmos secondary to orbital myopathy not due to Graves's disease.

An 18-month-old white female child presented with severe bilateral exophthalmos. She was thought to have Grave's disease because her orbital CT scan showed massively enlarge extraocular muscles. She was subsequently found to have myelomonocytic leukaemia. This was treated with radiation, with rapid resolution of her exophthalmos and exposure keratitis.

Diagnosis, Differential↗
PubMed1982

Exercise and CAD.

Explore the source record for details and available documents.

Coronary Disease↗
PubMed1981

Alcohol-induced biphasic background and stimulus-elicited EEG changes in relation to blood alcohol levels.

The effects of 0.8 g alcohol kg-1 on CNS processes as reflected in EEG changes were studied in controlled experiments in 14 subjects in relation to BAC levels. A Two Period Change-Over Design with repeated trials over time allowed us to ascertain the time course and to isolate alcohol-induced changes from diurnal variations and effects of sequence and period. Based on spectral analysis of analog EEG recordings, the study has shown differential patterns of bi-phasic or tri-phasic alcohol-induced EEG changes over time in a number of parameters in background and in stimulus-elicited EEG responses varying with the BAC level and the metabolic phase of alcohol biotransformation. An increase in alpha activity during the absorption phase, a shift in the median of the total spectral power to the right (upwards), a decrease in slow activity in the delta and theta bands, and a decrease in variability of the background EEG on one hand and a reduction in stimulus-elicited EEg responses in total spectral alpha, theta and delta bands on the other are all interpreted as a stimulating excitatory effect during the absorption phase, parallel to the increase in BAC. The reverse pattern in the first part of the elimination phase infers a decrease in cerebral activation reflecting the sedative, depressant action of alcohol in this phase. The effects observed in the last trial, to a certain extent interpreted as stimulating, were simultaneous with the beginning of the post-alcohol hangover phase.

Adult↗
PubMed1981

Colitis in the elderly. A reappraisal.

The records of 81 patients with colitis whose symptoms began after the age of 50 years were analyzed to determine the importance of ischemia as a cause of colitis in this age group and to evaluate the accuracy of previous diagnoses. Patients were classified by clinical, roentgenological and pathologic criteria. A retrospective diagnosis of ischemic colitis was made in three-fourths of the patients, one-half of whom had original discharge diagnoses of ulcerative, Crohn's or nonspecific colitis. This study supports our belief that ischemia is the most common cause of colitis beginning in patients older than 50 years of age. Moreover, the incorrect diagnosis of idiopathic inflammatory bowel disease in a large proportion of these patients may explain why colitis has been reported to behave differently in the elderly than in the young.

Aged↗
PubMed1981

Effect of surface porosity on early thrombogenicity using vascular grafts with two surfaces in sequence.

This experiment addresses the multifactorial dilemma of defining the ideal performance parameters of small internal diameter vascular grafts. We found silicone rubber vascular grafts with smooth surfaces remain acutely free of thrombotic deposits whereas grafts with rough surfaces promote a dispersed thrombus formation. This study also questions the concept that the thrombogenicity of one surface determines the thrombotic response of different and adjacent flow surfaces in the blood flow. Here the distinction between response to each surface was abruptly delineated and equal in intensity regardless of proximal or distal positioning. By studying the 2 surfaces in sequence, surface properties were evaluated using the minimal number of experiments by mitigating the effects of interanimal variability. This is an important consideration in an era of "cost accountability".

Animals↗