Search PubMed⌕ Search

Biomedical subjects

W Schuette

Publications and source records attributed to W Schuette.

11 recordsLinked to original sources
PubMed1996

An automated high capacity data capture and analysis system for the in vitro assessment of leukocyte adhesion under shear-stress conditions.

Parallel-plate flow chambers have been used to model the vascular microcirculation and study the in vitro dynamic adhesive interactions of leukocytes and human umbilical vein endothelial cells (HUVECs). We describe here a high capacity system which can simultaneously monitor the adhesive interaction of neutrophils and HUVECs in ten flow chambers. Automated data collection was achieved with an image analyzer controlling the autostage and autofocus attachments of an inverted microscope. Images from the flow chambers were captured via phase-contrast microscopy using a video camera and laser videodisk recorder. The images were downloaded off-line into an image analyzer for automated counting of rolling and adherent cells. Neutrophils were detected by their "phase bright' characteristics. An automated optimization procedure allowed the computer to choose the best setting for the selective detection of neutrophils. In addition, a method which utilized image averaging was used to distinguish between rolling and adherent cells. A comparison of the results obtained from the manual and automated counting methods revealed linear relationships for the counting of both adherent (r = 0.98) and rolling cells (r = 0.96) with counting efficiencies of 59% and 46%, respectively. The utility of the system was demonstrated by its ability to measure the adhesive interaction between neutrophils and HUVEC in response to stimulus such as interleukin-1 alpha (IL-1 alpha), histamine, or formyl-1-methionyl-1-leucyl-1-phenylalanine (fMLP). In conclusion, we have developed an automated assay which combines the capacity of ten flow chambers with a computerized data analysis system; the result is an efficient and reproducible assay which minimizes operator associated errors and biological variability.

Cell Adhesion↗
PubMed1986

A method to average immunofluorescent histograms.

Single parameter gated flow cytometric fluorescent histograms were obtained on normal donor blood mononuclear cells using several commonly available lymphocyte surface markers. A computer method was developed to average single parameter flow cytometric immunofluorescent histograms. The averaged histograms provide a means of pattern recognition for normal lymphocytes and will aid in the clinical evaluation of lymphocytosis. Averaged histograms may also serve as standards for more advanced analysis.

Flow Cytometry↗
PubMed1985

Normal human blood density gradient lymphocyte subset analysis: I. An interlaboratory flow cytometric comparison of 85 normal adults.

An interlaboratory flow cytometric comparison of several commercially available human lymphocyte subset reagents was undertaken in three different laboratories. Fresh Hypaque-Ficoll purified blood mononuclear cells were stained at 4 degrees C or 22 degrees C. Direct or indirect surface immunofluorescence was carried out at all sites using an EPICS V flow cytometer. Fullbright, 10-micron fluorescent polystyrene microspheres were used for optical alignment and standardization. A log integral fluorescent histogram gated on forward and right angle scatter was collected on 1-2 X 10(4) cells for each reagent and the proportion, of positive cell determined for each reagent. With the exception of one reagent, anti-B1, which showed an approximately twofold variation, all three laboratories showed remarkable agreement. Thus there was no significant difference noted for the following reagents: OKT4, CCT4, Leu 3a, Leu 2a, OKT8, or CCT8. We attribute these findings to the availability of quality reagents, precision instrumentation, and a standard lymphocyte preparation.

Adult↗
PubMed1985

A circulating myocardial depressant substance in humans with septic shock. Septic shock patients with a reduced ejection fraction have a circulating factor that depresses in vitro myocardial cell performance.

We have previously described a subpopulation of patients with septic shock who had a reversible depression of radionuclide-determined left ventricular ejection fraction (EF). To investigate the mechanism of this myocardial depression, an in vitro model of mammalian myocardial cell performance was established employing primary spontaneously beating rat myocardial cells. The contraction of a single cardiac cell was quantitated by recording the changes in area occupied by the cell during contraction and relaxation. In 20 septic shock patients during the acute phase, the mean left ventricular EF was decreased (mean = 0.33, normal mean = 0.50), and serum obtained during this acute phase induced a mean (+/- standard error of the mean) 33 +/- 4% decrease in extent and 25 +/- 4% decrease in velocity of myocardial cell shortening during contraction (P less than 0.001). In contrast, serum obtained from 11 of these same patients before shock (n = 2) or after recovery (n = 9) of the left ventricular EF (mean = 0.50) showed a return toward normal in extent and velocity of shortening (P less than 0.001). Sera from 17 critically ill nonseptic patients, from 10 patients with structural heart disease as a cause for a depressed EF, and from 12 healthy laboratory personnel, induced no significant changes in in vitro myocardial cell performance. In 20 patients during the acute phase of septic shock, the decreased EF in vivo demonstrated a significant correlation (r = +0.52, P less than 0.01) with a decrease in the extent of myocardial cell shortening in vitro. The quantitative and temporal correlation between the decreased left ventricular EF and this serum myocardial depressant substance argues for a pathophysiologic role for this depressant substance in producing the reversible cardiomyopathy seen during septic shock in humans.

Adolescent↗
PubMed1984

Influence of cell proliferation and cell cycle phase on expression of estrogen receptor in MCF-7 breast cancer cells.

In the present study, the effects of cell cycle phase and proliferation rate on the expression of specific estrogen binding activity were explored in hormone-dependent human breast cancer cells. A technique was developed to alter the proliferative rate of MCF-7 cells by plating at different densities. The doubling time ranged from 20 to 48 hr, showing a negative relation to the number of plated cells. Slowly proliferating cells had accumulated more than twice as much estrogen receptor (ER) activity as did fast-proliferating cells. Exposure of exponentially growing cells to isoleucine-deficient medium resulted in decreased thymidine incorporation and disappearance of detectable cellular ER activity. Overall protein synthesis was reduced by only 30% in cells growing in isoleucine-free medium. At 24 hr after release from isoleucine deprivation, ER levels are fully restored, although thymidine incorporation does not resume for an additional 6 to 8 hr, and increases in cell number are not seen for 24 hr. Exposure of exponentially growing cells to 2 mM thymidine for 24 hr produced partially synchronized MCF-7 cells (approximately 70%). Six hr after release from excess thymidine, cells reached S phase; after 9 hr, G2; and after 18 hr, G1. ER levels immediately and, 6 hr after release, remained unchanged, showed a slight increase at 9 hr, and showed an increase of about 50 to 60% at 18 hr. These data suggest that: (a) ER binding activity and DNA synthesis can be dissociated; (b) ongoing protein synthesis is necessary for maintenance of cellular ER activity; and (c) ER is apparently synthesized throughout the cell cycle, with some evidence that this is predominantly in G1 and G2.

Breast Neoplasms↗
PubMed1979

Hyperthermia potentiates doxorubicin-related cardiotoxic effects.

The intercurrent administration of doxorubicin hydrochloride to a patient undergoing whole-body hyperthermia for the treatment of metastatic cancer repeatedly produced ventricular irritability and cardiac dysfunction. Individually, doxorubicin and hyperthermia were tolerated by the patient without incident. Catecholamine determinations showed that the administration of doxorubicin under hyperthermic conditions increased the liberation of both epinephrine and norepinephrine. The acute synergistic cardiotoxic effects occurred with doxorubicin dosages that were severalfold less than those associated with only mild and transient ECG disturbances under normothermic conditions.

Arrhythmias, Cardiac↗
PubMed1979

Whole body hyperthermia: a phase-I trial of a potential adjuvant to chemotherapy.

Fourteen patients with a variety of neoplasms not responsive to standard forms of therapy underwent whole body hyperthermia for a maximum 4 h at 41.8 degrees C. This was a phase-I cancer trial designed to develop whole body hyperthermia as an adjuvant to systemic chemotherapy. Intravenous analgesia was used to sedate patients, obviating the need for general endotracheal anesthesia. Hyperthermia was induced by means of a high-flow water perfusion suit. Cardiovascular performance was evaluated using a flow-directed pulmonary artery catheter. Patients developed a twofold mean increase in cardiac index without evidence of cardiac damage by ECG or creatine phosphokinase (CPK) isoenzymes. An acute fall in serum magnesium and phosphate and an acute rise in arterial pH, serum CPK values, and granulocyte count occurred in all patients. There were no clotting abnormalities. Toxicity included fatigue, diarrhea, nausea, and transient elevations in liver enzymes. Four patients were febrile for 36 h after initial defervescence. Peripheral neuropathy developed in four. These results show that with carefully monitored conditions whole body hyperthermia is feasible.

Adolescent↗
PubMedDate not supplied

An evaluation of liquid-crystal thermometry as a screening device for intraoperative hyperthermia.

Disposable liquid-crystal temperature-trend indicators were evaluated under clinical conditions that simulated the development of intraoperative hyperthermia during anesthesia. Comparison was made to forehead thermistors for rapidity, accuracy, and linearity of response as well as correlation with esophageal and rectal thermistor recordings. The liquid-crystal monitors were comparable to the forehead thermistors in both rapidity and linearity or response, but not in accuracy. A linear correlation existed with the esophageal thermistor temperatures. Correlation with the rectal temperatures was not as exact. It is concluded that liquid-crystal thermometers may adequately serve as screening devices for intraoperative hyperthermia.

Body Temperature↗