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Biomedical subjects

P M Corry

Publications and source records attributed to P M Corry.

88 records · Page 5Linked to original sources
PubMed1979

Quantitation of antibody binding to cell surface antigens by x-ray fluorescence spectrometry.

An X-ray spectrometric method has been developed to quantitate antibody bindng to whole cell surfaces in order to obtain a distribution of binding within a population of cells. The method involves incubation of target cells with ferritin-labeled antibody. Analysis of prepared samples in a modified transmission electron microscope with an X-ray detector and data analysis equipment, yields quantitative results on the binding of labeled antibody to individual cells. The binding of anti-2,4-dinitrophenol serum to Chinese hamster ovary cells with attached 2,4-dinitrophenol haptens was measured by X-ray spectrometry. Measurements of attached hapten by a radioisotopic marker correlated with the X-ray spectrometric determination of bound antibody. The use of synchronized cells in metaphase and G1 phases of the cell cycle permitted investigations into the binding per unit surface area. The distribution of antibody binding among a given population of cells was related to the surface area of the cells.

Animals↗
PubMed1977

Hyperthermic effects on DNA repair mechanisms.

Studies have been carried out using neutral and alkaline sucrose density gradients to investigate the effect of 41 degree-43 degree C on the ability of Chinese hamster ovary cells to repair single (SSB) and double stranded DNA breaks (DSB) caused by exposure to ionizing radiation. The authors found that when hyperthermia exists prior to irradiation significant inhibition occurs. The data support the conclusion that unrepaired DNA damage may be lethal to the cell. Though no increase in radiation-induced DSB frequency was observed subsequent to hyperthermia, a 10-20% increase in SSB frequency was observed.

Animals↗
PubMed1976

Separation of ferritin labeled antibody from free antibody.

A procedure for the separation of ferritin-antibody conjugates from free antibody has been developed using isokinetic sucrose density gradient sedimentation. The gradient (5% w/w sucrose at the top to about 35% at the tube bottom) provides optimal separation of 7S free immunoglobulin from the ferritin (65S) and ferritin-antibody conjugate. Recovery of the conjugate band is simple and avoids problems of aggregation found by centrifugal pelleting and resuspension procedures. The method was tested by labeling human globulin and fractionating the gradient. Free antibody was detected at the top one-fifth of the gradient by immunodiffusion. Ferritin and the labeled antibody were found one-third to one-half of the way down the gradient. Immunoelectrophoresis was also used to demonstrate the separation of unconjugated ferritinand ferritin labeled antibody from free antibody.

Antibodies↗
PubMedDate not supplied

Introduction to hyperthermia device evaluation.

From 10/81 to 1/87, the National Cancer Institute (NCI) of the U.S. Department of Public Health Services (PHS) contracted with four institutions to evaluate hyperthermia technology to be applied in the treatment of human malignancy. During the five year period 1981-1986, data were collected which now reside in a consensus database representing treatments of 792 separate sites or fields in a total of 573 patients. These patients were treated with one or more of 49 devices by the four institutions. Sixteen ultrasound (US) devices were evaluated in 195 sites. Nine magnetic induction (MI) devices were evaluated in 208 sites. Twenty radiative electromagnetic (EM) devices were evaluated in 488 sites. Four interstitial (IRF) devices were evaluated in 37 sites. Many sites were treated with multiple hyperthermia modalities. This first in a series of 13 reports describes the general objectives of the Contractors' Group, basic methods of device evaluation and brief details of the large variety of devices tested.

Electromagnetic Phenomena↗
PubMedDate not supplied

Mechanism of drug-induced heat resistance: the role of protein degradation?

To investigate the possibility that heat-induced protein degradation may play a role in heat killing of mammalian cells, we have compared cellular survival and protein degradation rates for cells treated with cycloheximide, puromycin, or histidinol. These three compounds all inhibit protein synthesis and protect against the lethal effects of heat shock. When cells were treated with histidinol for 2 h before heating, as well as during heating at 43 degrees C for 3 h, they became resistant to heat killing. Histidinol treatment (5 mM) induced a 10,000-fold increase in surviving fraction from 10(-5) to 10(-1), and the protective effect was similar to that of 0.1 mM cycloheximide or 0.2 mM puromycin. Despite the similarity in heat protection for the three compounds, the protein degradation rate of 1.8%/h at 37 degrees C was increased by 34% by histidinol and decreased 20% by cycloheximide or puromycin. At 43 degrees C none of these compounds had a significant effect on the protein degradation rate. Therefore the intracellular degradation of relatively long-lived proteins does not appear to play a significant role in either heat killing or the phenomenon of heat protection. Instead, since maximum protection from heat killing was observed for all three compounds when protein synthesis was inhibited by 90-95%, heat protection probably results from an event(s) that is caused by inhibition of protein synthesis.

Animals↗
PubMedDate not supplied

Application of the time-dependent Green's function and Fourier transforms to the solution of the bioheat equation.

A theory for solving the bioheat equation is developed using a time-dependent Green's function and Fourier transform techniques. The description of both steady-state and time-dependent data are placed into a single framework which can also describe the effects of inhomogeneous blood perfusion. The theory is illustrated by examples including the modelling of a thermal conduction hyperthermia system and a new RF interstitial system. A possibility for measuring the blood perfusion parameter and thermal conductivity from the steady state temperature distribution of a point source is also proposed.

Fourier Analysis↗