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Biomedical subjects

C Pidgeon

Publications and source records attributed to C Pidgeon.

42 records · Page 3Linked to original sources
PubMed1983

Macrophage activation: synergism between hybridoma MAF and poly(I). Poly(C) delivered by liposomes.

High concentrations of a murine T cell hybridoma culture supernatant containing macrophage-activating factor (MAF) rendered resident mouse peritoneal macrophages cytotoxic for P815 mastocytoma cells. The capacity of the hybridoma-derived MAF (MAFH) to induce tumoricidal activity increased 10(3) to 10(4)-fold when the lymphokine was encapsulated into liposomes. Combinations of MAFH and poly(I) X poly(C) acted synergistically to render macrophages potently cytotoxic. Subthreshold (nonactivating) concentrations of free or liposome-encapsulated MAFH increased the potency of free poly(I) X poly(C) and liposome encapsulated poly(I) X poly(C). Either as free agent or encapsulated in liposomes, single-stranded poly(I) or poly(C) did not activate macrophages in the presence or absence of MAFH. Double-stranded poly(I) X poly(C) was thus required for macrophage activation and synergism with MAFH.

Animals↗
PubMed1981

Calculating number and surface area of liposomes in any suspension.

Simple formulas for calculating the total surface area and number of liposomes in any liposome population are presented. The necessary parameters for calculating these values are the encapsulation ratio (or efficiency) of the population. When tested on theoretical liposome populations, excellent results are obtained regardless of the heterogeneity of the population.

Lipids↗
PubMed1981

Papilledema in two patients with acromegaly and intrasellar pituitary tumors.

Two patients had bilateral papilledema complicating acromegaly. Both patients had enlarged blind spots, but otherwise visual fields were normal. Suprasellar extension of the pituitary tumors was diligently sought with the use of visual field examination, pneumoencephalography, internal carotid arteriography, and computed axial tomography, and tumor extension did not exist. Transphenoidal and transethmoidal routes were used to perform partial hypophysectomies in these patients. The procedure was completely successful in one patient and partially successful in the other patient. After hypophysectomy, papilledema resolved in both patients. This beneficial effect may be the result of anatomical changes, the reduction in growth hormone levels, or both. These observations suggest that the acromegaly may be different from papilledema that occurs secondary to suprasellar expansion of pituitary tumors.

Acromegaly↗
PubMed1980

Unique approach to calculation of first-order absorption rate constants from blood or urine data.

Several methods are employed to estimate an apparent first-order rate constant for absorption in a one-compartment model. A method for calculation of the absorption rate constant (Ka) has been derived based on the area under the concentration-time curve for blood data or the area under the excretion rate-time curve for urine data between the observed time of maximum concentration or rate (tmax) and the maximum concentration (Cmax) or maximum rate of excretion (Xu max). The method obviates the need for large numbers of samples in the absorptive phase. The method also avoids extensive calculation and is less influenced by errors in data points prior to Cmax or Xu max, where the rate of change is rapid and error is likely. The methods have been tested on theoretical data with and without error generated using a ragne of values for Ka and elimination rate constants (KE). Errors in the estimate Ka are proportional to error in the data. The method compares favorably with nonlinear regression analysis.

Absorption↗
PubMed1977

Unique approach for calculation of absorption rate constant.

Several methods are employed to estimate an apparent first-order rate constant for absorption in a one-compartment model (Ka). These include curve-stripping, nonlinear least squares regression, and the Wagner-Nelson approach. The Wagner-Nelson method in particular requires extensive calculation and may be subject to error. A method for calculation of the absorption rate constant has been derived based on the relationship between area under the concentration-time curve, between time of maximum concentration (tmax) and infinity, and maximum concentration (cmax). The method obviates the need for large numbers of samples in the absorptive phase. The method also avoids extensive calculations and is less influenced by errors in data points prior to Cmax where the rate of change of concentration is very rapid and error is likely. The value for Ka is corrected for by the error found in tmax (calculated using the estimated Ka) relative to the observed tmax. The method has been tested on theoretical data with and without error generated using a range of a and KE. Errors in the estimate of Ka are proportional to error in the data.

Intestinal Absorption↗