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Biomedical subjects

S Stewart

Publications and source records attributed to S Stewart.

At least 289 records · Page 16Linked to original sources
PubMed1985

Monoclonal antibody associated with a lymphocyte subpopulation in chronic lymphocytic leukemia.

An IgG monoclonal antibody that detects a subpopulation of lymphocytes found in peripheral blood and bone marrow of patients with CLL and malignant lymphoma is described. The initial immunization used to achieve the resultant monoclonal antibody included the use of cells obtained by DNA transformation of mouse L-cells with the DNA obtained from a morphologically altered somatic cell hybrid between primary human CLL peripheral lymphocytes and a flat-revertant Chinese hamster ovary (CHO) cell line designated GRC+L-73. Hybridomas were thus selected as potentially recognizing antigens associated with the morphological transformation induced by hybridization of CHO cells with lymphocytes from lymphocytic malignancies. One such hybridoma, designated 37-28, was selected for further investigation. The monoclonal antibody produced was IgG (gamma G2a) and detects a subpopulation of lymphocytes present in hematological specimens of some of the lymphocytic malignancies.

Animals↗
PubMed1985

Superior sternal cleft: repair in the newborn.

Superior sternal cleft is a rare congenital anomaly that should be repaired in the newborn while the bony thorax is still compliant. A method of approximating the U-shaped sternal defect that is applicable to the majority of patients seen as newborns is described.

Humans↗
PubMed1985

Complete endocardial cushion defect: the late result of repair using the single-patch technique.

Twenty-two patients have been followed for between 1 and 105 months after repair of a complete endocardial cushion defect. The mean period of follow-up is 3.5 years. The single-patch technique was used in every patient. The mitral valve was repaired with buttressed sutures in those seen more recently. The mean age at the time of operation was 15 months. Early in this experience, 4 patients had severe mitral valve incompetence after an initially satisfactory repair. In none of those patients had the mitral valve been repaired with pledgeted sutures. Two of those patients survived reoperation, and 2 died before a second operation could be performed. Every mitral valve is now repaired with pledgeted sutures, and there have been no failures of the mitral valve reconstruction. Each patient has been followed by the same pediatric cardiologist every 6 to 12 months after operation. The vast majority (17 of 20) are asymptomatic. Twelve have no mitral valve incompetence, and the remainder have only trivial or mild incompetence. Clinically, the pulmonary artery hypertension has resolved in 19 of 20 patients. Each patient remains in normal sinus rhythm. The long-term results following repair of complete endocardial cushion defect with the single-patch technique are excellent, but pledgeted sutures should be used in the mitral valve repair to insure its integrity.

Endocardial Cushion Defects↗
PubMed1984

Cultivation of murine bone marrow macrophages in sponges: a method that permits recovery of viable cultured cells.

Various investigators have cultured murine bone marrow or peritoneal cells in vitro on glass or plastic surfaces with the ultimate aim of retrieving adherent macrophages for morphologic and functional evaluation. The removal of these adherent macrophages by conventional techniques has been consistently accompanied by low yield and significant cell damage. We report here a simple technique for culturing murine bone marrow cells in gelatin sponges (Spongostan and Gelfoam) in growth medium containing 10% fetal bovine serum and 10% L-cell conditioned medium. Viable cells were retrieved from the sponges in 10 min by digestion with collagenase. The in situ growth kinetics were similar to those found for cells cultured on plastic dishes. The recovered cells were adherent, phagocytic, positive for Fc gamma receptors, and had esterase activity.

Animals↗
PubMed1984

Monoclonal antibodies distinguish phase variants of Coxiella burnetii.

Monoclonal antibodies (MAbs) directed against phase I and II variants of Coxiella burnetii were produced by fusing myeloma SP2/O-AG 14 cells with spleen cells from mice immunized with the chloroform-methanol extraction residue of phase I whole cells. Two hybridoma clones which distinguished the phase variants by microimmunofluorescence assay were isolated and characterized. The MAbs showing specificity for phase I cells (MAbI-1, immunoglobulin G, subclass 3 kappa) reacted with the hot phenol-water extract of phase I C. burnetii in immunodiffusion and enzyme-linked immunosorbent assays. MAbI-1 reacted with high-molecular-weight components from phase I phenol-water extract and whole cell in an immunoblot assay. Specificity of MAbI-1 for a carbohydrate epitope in the phenol-water extract was demonstrated by periodic acid inactivation of binding by a competitive enzyme-linked immunosorbent assay. Phase I antigenic sites were apparently well represented on the surface of cells as demonstrated by complete fluorescence and microagglutination. The MAb showing specificity for phase II cells (MAbII-1, immunoglobulin G, subclass 2b kappa) reacted with whole cells in the microimmunofluorescence assay, microagglutination test, complement fixation test, and the enzyme-linked immunosorbent assay. MAbII-1 reacted specifically with a 29,500-dalton surface protein as demonstrated by immunoprecipitation of 125I-surface-labeled cells. Although MAbII-1 reacted with detergent-solubilized protein, it did not react with sodium-dodecyl sulfate-denatured protein by immunoblot assay. This protein was not exposed on the surface of phase I cells, but chloroform-methanol extraction of phase I cells exposed the phase II epitope.

Animals↗
PubMed1984

Neuropathological findings in Miller Fisher syndrome.

The neuropathological findings in a fatal case of Miller Fisher syndrome are described. The demyelinating peripheral neuropathy and normal appearance of the central nervous system that were observed support the inclusion of the syndrome within the spectrum of acute inflammatory polyneuropathy.

Aged↗
PubMed1984

Randomized trial of total parenteral nutrition in critically ill patients: metabolic effects of varying glucose-lipid ratios as the energy source.

We studied 20 critically ill patients receiving ventilatory support to determine both their metabolic requirements and the effect of providing energy substrate regimens containing different lipid to glucose calorie ratios on whole-body protein economy. The measurements used included indirect calorimetry, substrate hormone profile, and whole body protein turnover by [14C]leucine. Measurements were done while patients were receiving all their nonprotein calories as dextrose ( D100 ) and were compared with results obtained when they received all their nonprotein calories as a combination of dextrose and lipid in a calorie ratio either of 3:1 ( D75 ) or 1:3 ( D25 ). To maintain euglycemia, exogenous insulin was infused by attending physicians not cognizant of the total parenteral nutrition regimen used. Energy expenditure before receiving total parenteral nutrition was only 4.6% above basal, and did not rise significantly during any of the regimens. The insulin infusion rate, plasma insulin, CO2 production, and serum lactate were significantly higher with D100 than with D25 , but not with D75 . Correspondingly, plasma free fatty acids were significantly lower with D100 when compared with D25 but not with D75 . Despite this, there were no significant differences in whole-body protein synthesis, breakdown, or net synthesis (synthesis - breakdown) and, in general, the patients in all groups were close to zero protein balance. These data suggest that critically ill patients are not severely hypermetabolic, and that they can maintain protein balance with a modest excess of calories while using a wide range of fuel mixtures.

Adult↗
PubMed1984

A "serum-free" medium for the production of erythropoietic bursts by murine bone marrow cells.

We describe a culture medium that does not require the addition of serum, in which erythropoietic bursts are produced from murine bone marrow cells with efficiencies at least as great as those of serum-containing media. Four ingredients were shown to be essential: bovine serum albumin (BSA), transferrin, cholesterol, and erythropoietin. The system supported burst formation without the addition of conditioned medium as source of burst-promoting factor(s). To include cholesterol in the medium we found that there was no necessity for sonication, nor for subsequent evaporation of the ethanol in which the cholesterol was dissolved. Filtration of cholesterol and delipidation of BSA both impaired the ability of the medium to support burst production. The "serum-free" medium described here, even though not truly defined, is useful for erythropoietic culture: it is reliable, highly efficient in supporting burst formation, and simple and economical to prepare from ingredients readily available from commercial sources without the need for special testing.

Animals↗
PubMed1983

Echocardiographic definition of right pulmonary venous connection at catheterization.

Traditional methods of identifying partial anomalous pulmonary venous connection to the right atrium in the presence of an atrial defect are not always reliable. Twenty patients were studied with a new technique in which the catheter is introduced into the right superior pulmonary vein followed by echocardiographic assessment of the catheter position in relation to the left atrium and atrial septum. The insertion site of the right pulmonary veins was detected in every patient and in ten patients has been verified at operation. This approach can be performed rapidly and appears to be accurate as well as reliable.

Adolescent↗
PubMed1983

A controlled trial of the effect of parenteral nutritional support on patients with respiratory failure and sepsis.

Energy and protein metabolism was studied in 11 septic patients receiving ventilatory support while on three different intravenous regimens. They received 5% dextrose in water (D5W), and one of two different regimens of parenteral nutritional support (PNS); either amino acid and dextrose (PNA) or amino acid and dextrose and lipid (PNB). All patients were given D5W and PNS in random order. The energy intake was targetted to exceed by 50% the measured metabolic rate. On D5W the mean measured energy expenditure was only 15.2% above the expected energy expenditure (p<0.02). A respiratory quotient of 0.75 while on D5W showed that in the absence of PNS the major part of energy requirements came from fat oxidation. In addition, on D5W these patients were in negative nitrogen and protein (synthesis-catabolism) balance. With PNS the metabolic rate rose significantly (p<0.02). While on PNA, the CO2 production was significantly higher than with PNB, and despite receiving all non-protein energy as glucose, the patients continued to oxidise fat to meet about 30% of their energy requirements. Continued fat oxidation was found to be associated with insulin resistance and high catecholamine levels, suggesting a cause and effect relationship. PNS caused an increase in protein (synthesis - catabolism) and nitrogen balances, and reduced leucine oxidation. The fall in leucine oxidation was greater on PNB than on PNA. Protein and nitrogen balances, expressed per gram of amino acid infused, were significantly better with PNB than PNA. It was concluded that insulin resistance may make fat an efficient source of energy.

Journal Article↗
PubMed1983

Skin necrosis as a consequence of coumadin therapy.

Skin necrosis secondary to Coumadin-congener therapy is a rare, unpredictable complication. A case is reported of a patient given sodium warfarin therapy following coronary artery bypass who developed skin necrosis of the trochanteric region, bilaterally, and the right breast on the fourth day following administration of Coumadin. The Coumadin therapy was discontinued, and the areas of skin necrosis went on to slow, spontaneous healing. However, significant subcutaneous induration persisted, although the areas were no longer painful.

Breast↗
PubMed1983

Budgets.

Explore the source record for details and available documents.

Budgets↗
PubMed1983

Do preoperative laboratory tests predict blood transfusion needs in cardiac operations?

We retrospectively compared preoperative prothrombin (PT), partial thromboplastin (PTT), dilute whole blood clot lysis and bleeding times, fibrinogen level, and platelet count with subsequent blood component administration in 92 patients who had undergone cardiac operations with cardiopulmonary bypass (CPB). Abnormal results for one or more tests were found in 34% of 71 adults and 81% of 21 children and teenagers. The patients with abnormal test(s) received no more whole blood and packed red cell units, platelets, or plasma than those with normal tests in either age group. No individual or multiple test abnormalities predicted excess blood component transfusion, even when low-grade abnormalities were excluded. The high rate of abnormal tests in patients less than 20 years of age was not due to polycythemia and may indicate a need for age-specific reference ranges. Baseline PT, PTT, and platelet count may aid in the evaluation of the potential for subsequent development of coagulopathy, but we conclude that further preoperative testing may be reserved for infants, polycythemic individuals, or others in whom history or drug use suggests potential bleeding problems.

Adolescent↗
PubMed1983

The Hancock external valved conduit. A dichotomy between late clinical results and late cardiac catheterization findings.

The Hancock external valved conduit was inserted in 18 children between 1974 and 1977. Seventeen patients survived operation and 15 are long-term survivors of 6 to 9 years. All patients have been closely followed up by the same pediatric cardiologist and each has undergone serial cardiac catheterization studies, generally performed at 1 and 6 years after operation. All long-term surviving patients have been in either New York Heart Association Class I or II. A few continue to take digoxin or diuretics. Cardiac catheterization demonstrated a gradient of 50 mm Hg or greater across the conduit in two of 16 patients 1 year after operation and in seven of 15 patients 6 years after operation. Five patients (30% of all long-term survivors) have had this conduit replaced and each has survived reoperation. The finding of a severe conduit gradient in one third of all long-term surviving patients is particularly bothersome since these patients were essentially asymptomatic. This study emphasizes the need for serial follow-up cardiac catheterization studies in all patients who receive the Hancock conduit.

Adolescent↗