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S S Stewart

Publications and source records attributed to S S Stewart.

18 recordsLinked to original sources
PubMed1992

Cellular heterogeneity in human transitional cell carcinoma: an analysis of optical properties and lectin binding.

Flow cytometry was used to measure the binding of a panel of ten fluorescein isothiocyanate(FITC)-conjugated lectins to fifteen samples of normal and neoplastic human urothelium. Concurrent measurement of light scattering and fluorescence permitted the quantification of lectin binding to cellular subpopulations defined by their light-scattering properties. In normal urothelium, we previously demonstrated levels of lectin binding to the cellular subpopulations derived from the superficial and intermediate cell layers which were higher than levels which bound to the subpopulation derived from the basal cell layer (Ward et al., 1987). This difference was most marked with Maclura pomifera agglutinin (MPA), Ricinus communis agglutinin (RCA) and Ulex europeus agglutinin (UEA). We now report a similar correlation between the degree of differentiation of a cellular subpopulation and the level of lectin binding in human transitional cell carcinomas (TCCs). Morphological differentiation in human TCCs is accompanied by alterations in cell-surface carbohydrates which are similar to those which accompany cellular differentiation in the corresponding normal tissue. No systematic difference in lectin binding was observed between the corresponding subpopulations of normal and neoplastic urothelial cells.

Carbohydrate Metabolism↗
PubMed1989

Enhancement of hybridoma production by medium supplemented with murine ascitic fluid.

We have greatly improved the yield after cell fusion of antigen-specific monoclonal antibody-secreting murine hybridomas by substitution of Sp2/0 ascites for fetal bovine serum (FBS) in the culture medium. As a medium supplement for established cultures, Sp2/0 ascites at 2.5% in Dulbecco's modified Eagle's medium (DMEM) provided growth characteristics similar to media containing 10% or 20% FBS. All culture parameters associated with hybridoma fusion experiments, however, were advantageously affected in ascites-supplemented cultures. Clonal growth of hybridomas from the single cell stage was enhanced at least two-fold over 20% FBS-supplemented medium. Following fusion, both the number of colonies and hybridoma growth rates were substantially increased for ascites-containing cultures. Most importantly, the number of antigen-specific antibody-secreting hybridomas was increased in Sp2/0 ascites supplemented cultures, five-fold in the eight fusion experiments presented here. This improved performance compared to FBS-supplemented medium is reproducible from lot to lot of ascites.

Animals↗
PubMed1989

Identification of basic fibroblast growth factor as a cholinergic growth factor from human muscle.

Dissociated embryonic chick ciliary ganglion cells in culture were used as a bioassay to isolate a cholinergic growth-promoting protein from extracts of autopsied adult human muscle. An active protein was purified after acid and salt precipitation of extract, cation exchange, molecular sieving, heparin affinity chromatography, and in some cases, SDS-PAGE. This protein increased levels of choline acetyltransferase activity and ACh synthesis with time in culture. The protein was identified as basic FGF by several criteria. It shared the high affinity for heparin and was the same approximate molecular weight, 18 kD, as basic FGF. Activity was removed from solution by antibodies specific for basic FGF. Recombinant human basic FGF was equally effective in stimulating CAT activity, but was not additive with our purified protein at saturating concentrations. Basic FGF was also found in extracellular matrix and conditioned medium from cultured embryonic chick muscle. The activity could be released from extracellular matrix by treatment with heparinase or high salt extraction. Basic FGF stimulates neurite outgrowth as well as the capacity for transmitter synthesis. Thus, basic FGF is present in embryonic and adult muscle and capable of acting as a growth regulator for cholinergic neurons.

Acetylcholine↗
PubMed1989

Trophic effects of skeletal muscle extracts on spinal cord cultures.

A soluble extract of newborn rat muscle was added to cultures of dissociated embryonic spinal cord cells in order to determine the effect on their morphology. The processes per cell ratio, and the length of neurites were all enhanced by the presence of extract in ventral cord cell cultures, but not in dorsal cord cell cultures. It is possible that muscle-derived neurotrophic factors regulate the in vivo phenomenon of neuronal cell death. Interference with neuron-muscle trophic communication, either directly or indirectly, might lead to excessive loss of motor neurons. This mechanism may be important in the pathogenesis of amyotrophic lateral schlerosis.

Animals↗
PubMed1989

Phenylephrine.

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Drug Interactions↗
PubMed1988

Purification of a skeletal muscle polypeptide which stimulates choline acetyltransferase activity in cultured spinal cord neurons.

Extracts of rat skeletal muscle contain neurotrophic factors which stimulate the development of choline acetyltransferase in embryonic day 14 rat spinal cord cultures. The trophic activity does not bind heparin-Sepharose or lectin affinity columns. However, mild acid treatment separates the trophic activity into soluble and insoluble fractions. The acid-insoluble activity has been purified 5000-fold to apparent homogeneity using preparative sodium dodecyl sulfate gel electrophoresis to achieve final purification. The purified factor migrates as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing, with an apparent molecular mass of 20 kDa and a pI of 4.8. The activity and apparent molecular weight of the purified factor are unaltered by treatment with reducing agents or incubation in acidic conditions. Activity, however, is destroyed by heating or protease treatment. Thus, the factor appears to be a single polypeptide without significant levels of glycosylation or charge microheterogeneity. These results represent the first purification of a neurotrophic factor from skeletal muscle. The physical properties and amino acid composition of this factor differ from those of nerve growth factor and heparin-binding growth factors, as well as from the neurotrophic factor from heart cell conditioned medium which induces cholinergic development in sympathetic neurons.

Aging↗
PubMed1988

A double-blind study of the effectiveness of cyclosporine in amyotrophic lateral sclerosis.

In a double-blind placebo-controlled trial of cyclosporine in amyotrophic lateral sclerosis, no differences were observed in the monthly rate of progression or the relative risk of progression in comparing 38 patients randomized to the placebo group and 36 patients randomized to the cyclosporine group. In comparing three subgroups of patients, cyclosporine appeared to benefit men who entered the study within 18 months of the onset of first symptoms, whereas it was of no value to women or to men who entered later than 18 months. For the men with recent onset of disease, the relative risk of progression was 0.403; the monthly rate of progression was 5.2 +/- 1.1 points with placebo and 3.5 +/- 0.7 points with cyclosporine. These provocative results support the need for a full study of cyclosporine in men with recent onset of disease.

Amyotrophic Lateral Sclerosis↗
PubMed1988

Cancer patients' perceptions of their disease and its treatment.

One hundred cancer patients undergoing active treatment were interviewed to determine how they perceived their illness and how their perceptions compared with those of their attending physicians. Ninety-eight patients recognized that they had cancer and 87 correctly identified the tumour type. Sixty-four of 67 patients with local or regional disease were aware of this, but 11 of 33 patients with metastatic disease incorrectly believed that the cancer was localized. Five of 52 patients being treated for cure thought they were being treated palliatively, and 16 of 48 patients receiving palliative treatment believed that the doctor's aim was to cure them. Forty of these 48 patients significantly overestimated the probability that the treatment would prolong their lives. Patients with little secondary education were significantly more likely to underestimate the seriousness of their condition. Interactions between doctor and patients were not observed directly and it was therefore not possible to determine whether patients' inaccurate views of their illness were due to suboptimal communication or denial. Doctors frequently failed to recognize their patients' misconceptions. In only one of the 16 cases in which a patient, who was being treated palliatively, believed that the treatment was curative did the doctor recognize that this misunderstanding existed.

Adult↗
PubMed1988

Trophic factors in neurologic disease.

Recent studies suggest that diffusible factors released by neural targets enhance the survival, growth, and differentiation of neurons both peripherally and in the central nervous system. Evidence for such trophic factors exists for many of the neural systems involved in the degenerative neurologic diseases Alzheimer's disease, parkinsonism, and amyotrophic lateral sclerosis. It is our hypothesis that for each of these disorders there is both a primary insult and a secondary effect. The primary insult may have multiple etiologies, but the secondary effect is the result of retrograde degeneration. Such retrograde degeneration occurs because of an impairment of trophic factor function or an inadequacy of trophic effects to keep pace with the primary destructive process. Accordingly, it may be possible to exploit such trophic mechanisms to define further the pathobiology of neural degeneration and to develop specific treatments for currently incurable illnesses.

Alzheimer Disease↗
PubMed1988

Cerebral vasculitis in relapsing polychondritis.

Recurrent inflammation of cartilage in multiple sites is a hallmark of relapsing polychondritis (RP). Neurologic complications of this disease have begun to attract increasing attention, but the neuropathologic basis of these complications has not been described. We report a patient with RP whose autopsy showed extensive cerebral and systemic vasculitis.

Cerebrovascular Disorders↗
PubMed1987

A rating scale for amyotrophic lateral sclerosis: description and preliminary experience.

A rating scale has been developed to provide a quantitative estimate of clinical status and disease progression in amyotrophic lateral sclerosis (ALS). This scale includes assessment of swallowing, speech, and respiratory function, and both strength and function of upper and lower extremity musculature. The evaluation is relatively simple to perform and yields reproducible data for both a total ALS score and a score for each group of functions tested. A score of 30 points is normal; 164 points indicates maximal dysfunction. The total ALS score increased in a linear fashion in each of 74 patients followed for at least one year. Among patients, the rate of disease progression varied twenty-fold, with a continuous distribution from the slowest to most rapid course. Thirty-four percent of patients exhibited a rapid change of greater than 48 points in the year, predicting progression to a terminal stage in less than two years; 19% of patients exhibited a slow change of less than 13 points in one year, predicting progression to a terminal stage over at least five years. This ALS scoring system should permit more accurate assessment of drug efficacy in clinical trials and correlation of rates of progression with clinical variables.

Amyotrophic Lateral Sclerosis↗
PubMed1987

Cellular heterogeneity in normal and neoplastic human urothelium: a study using murine monoclonal antibodies.

To assist in the description of the cellular heterogeneity present in normal and neoplastic urothelium, a panel of monoclonal antibodies (MoAbs) was raised against human transitional cell carcinoma (TCC) of the urinary bladder. All immunizations were carried out using whole cells and membrane preparations from well differentiated human TCCs. Two fusions produced 145 hybridomas. Following primary screening by ELISA and secondary screening with immunohistochemistry, three useful antibodies were identified. MoAb 35.48 binds to all cell layers of the normal urothelium and well differentiated tumours, but not to the majority of poorly differentiated tumours. MoAb 21.48 binds preferentially to the basal cell layer of normal urothelium and to some well differentiated papillary TCCs, but poorly differentiated tumours exhibit diffusely positive staining. MoAb 21.48 also shows cross-reactivity with basal cell layers of other epithelia. MoAb 5.48 binds preferentially to the superficial cell layers of normal urothelium and well differentiated TCCs, but exhibits less binding in poorly differentiated tumours with loss of the preferential superficial staining. Quantitative flow cytometric studies indicate that MoAb 5.48 binds to a cell-surface antigen which is present on significantly fewer cells of poorly differentiated tumours than on either normal urothelium (P less than 0.05), or well differentiated tumours (P = 0.05).

Animals↗
PubMed1986

Amyotrophic lateral sclerosis. Associated clinical disorders and immunological evaluations.

We examined the family history and associated diseases in 58 patients with amyotrophic lateral sclerosis (ALS), as well as the T-cell phenotypes and functions in 46 consecutive patients with this disorder. A family history of thyroid disease was present in 19%, and an additional 21% of patients described family members with other possible autoimmune disorders. In 19% of the patients with ALS either past or present thyroid disease was documented. Eleven of 47 additional patients with ALS had significant elevations of microsomal and/or thyroglobulin antibody levels. The T-cell phenotypes and functions were comparable in the ALS and control groups, with the exception of the presence of Ia antigen. In patients with ALS, 11.9% of the T cells were positive for the la antigen, while in both a normal control population and a non-ALS neurologic disease population, only 6.4% of T cells have this antigenic determinant. These data support involvement of autoimmune mechanisms in ALS.

Adult↗
PubMed1986

Realtime acquisition, storage, and display of correlated three-parameter flow cytometric data.

A microprocessor-based system which performs realtime correlated acquisition, storage and display of multiparameter (3-parameter) data from a flow cytometer (FACS-III) is presented. List-mode techniques are not employed. The 3-parameter data is collected and correlated, then displayed along with cell-frequency as a realtime 3-parameter colour scattergram, while the experiment is in progress; in addition, correlated and uncorrelated higher-resolution projections of the 3-parameter data are collected and stored. The data projections may also be displayed: as 1-parameter histograms, or as 2-parameter colour or grey-scale scattergrams. Examples of 2- and 3-parameter colour scattergrams are presented. The speed and some characteristics of the realtime acquisition and display software are examined; methods to increase the realtime speed are discussed.

Blood Platelets↗
PubMed1986

Cellular heterogeneity in normal human urothelium: an analysis of optical properties and lectin binding.

Flow cytometry was used to study the optical properties of normal urothelial cells in suspension. Narrow-angle light scatter, which is a function of cell size, defined one major and one minor cell population, and 90 degrees light scatter, a function of intracellular structure, showed three distinct cell populations. These properties were displayed as a 2-dimensional dot plot or "fingerprint" which proved to be characteristic and reproducible from one specimen of urothelium to the next. Cell sorting on the basis of these two parameters demonstrated that the small cells of the basal layer occupy the low narrow angle, low 90 degrees light-scatter region; the giant cells of the superficial layer lie in the high narrow angle, high 90 degrees scatter region; and the pyramidal cells of the intermediate layer lie in an intermediate zone. Studies of tissue sections using the galactose-specific, FITC-conjugated Maclura Pomifera lectin (MPA) demonstrated preferential binding to the superficial layers of intact urothelium. In order to quantify the apparent differences in lectin binding between the superficial and basal layers, urothelial cell suspensions were labeled with FITC-conjugated MPA and studied by flow cytometry. The resolution obtained on the basis of light scatter made it possible to quantify the difference in lectin binding to the three morphologically recognized cell types present in normal urothelium.

Cell Separation↗
PubMed1985

Platelet inhibitors and hydroxyethyl starch: safe and cost-effective interventions in coronary artery surgery.

This study evaluated the cost-effectiveness and clinical safety of utilizing hetastarch in pump prime solutions and for colloid replacement postoperatively in conjunction with the platelet inhibitors, aspirin and Persantine (dipyridamole). Sixty-four adult patients undergoing a coronary artery bypass operation were divided into two groups. Group 1 (N = 32) received only Persantine (75 mg three times a day) on the day prior to operation. Group 2 (N = 32) received the same Persantine dose plus aspirin (325 mg). In both groups, aspirin and Persantine were continued postoperatively and hetastarch was used as the colloid of choice. All patients were evaluated for blood loss, coagulation profiles, cost of blood and colloid replacement, and clinical course. Group 2 patients demonstrated significantly greater blood loss (p less than 0.05) but the same postoperative coagulation profiles as Group 1. The transfusion requirement (3.6 units versus 1.3 units) and cost basis ($252 versus $91) for patient care were higher in Group 2. Hetastarch had no effect on blood loss and was not associated with any adverse clinical reactions. Annual institutional savings based on utilization of hetastarch were calculated at $33,500 to $40,500 per 500 patients. We conclude that preoperative administration of aspirin (325 mg) is associated with increased perioperative blood loss and higher patient costs, two variables not demonstrable with Persantine only. Use of hetastarch combined with postoperative platelet inhibition was clinically safe and was a cost-effective method of colloid replacement.

Aspirin↗
PubMedDate not supplied

Cellular heterogeneity in normal human urothelium: quantitative studies of lectin binding.

A panel of 10 FITC-labelled lectins (MPA, PNA, ConA, DBA, SBA, RCA-120, WGA, UEA, GS-I, GS-II+) was applied to cryosections of seven specimens of normal urothelium. Seven of the lectins (MPA, ConA, RCA, WGA, UEA, GS-I and GS-II) showed a pattern of increasing fluorescence intensity from basal to superficial cells of the urothelium whereas PNA, DBA and SBA showed more uniform binding throughout the urothelium. Urothelial cell suspensions labelled with FITC-lectins were studied by flow cytometry to quantify the variation in binding to different cells types. Three cellular subpopulations were identified in normal urothelium on the basis of their optical properties. Fluorescence intensity due to specific lectin binding was then measured separately for each subpopulation. Although there was some variation among individual cases, a general pattern emerged in this small series. WGA, RCA, and GS-II bind in large quantities to all urothelial cells while PNA, SBA, ConA and DBA show little binding. MPA, RCA, UEA and GS-I showed the most marked increase in fluorescence intensity from basal to superficial cells as observed microscopically and quantified by flow cytometry.

Adult↗