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Biomedical subjects

C E Pearson

Publications and source records attributed to C E Pearson.

29 records · Page 2Linked to original sources
PubMed1993

Pressure changes in the eye due to an injection of inert gases: a theoretical model.

In the repair of retinal tears and detachments, the vitreous humor is often completely replaced with a temporary mixture of gases, one of which is not normally found in the bloodstream. The resulting bubble can then support the healing retina. There is diffusion of gases, however, from the bubble into the bloodstream and vice versa. This alters the intraocular pressure, with possible adverse consequences, as the intraocular pressure must be maintained within a certain range for the procedure to be successful. A simple model has been developed to predict the evolution of intraocular pressure over time, given a certain initial mixture of injected gases. This model could be useful in determining what mixture to use to support effectively and safely a healing retina.

Capillaries↗
PubMed1991

Plasmids bearing mammalian DNA-replication origin-enriched (ors) fragments initiate semiconservative replication in a cell-free system.

Four plasmids containing monkey (CV-1) origin-enriched sequences (ors), which we have previously shown to replicate autonomously in CV-1, COS-7 and HeLa cells (Frappier and Zannis-Hadjopoulos (1987) Proc. Natl. Acad. Sci. USA 84, 6668-6672), were found to replicate in an in vitro replication system using HeLa cell extracts. De novo site-specific initiation of replication on plasmids required the presence of an ors sequence, soluble low-salt cytosolic extract, poly(ethylene glycol), a solution containing the four standard deoxyribonucleoside triphosphates and an ATP regenerating system. The major reaction products migrated as relaxed circular and linear plasmid DNAs, both in the presence and absence of high-salt nuclear extracts. Inclusion of high-salt nuclear extract was required to obtain closed circular supercoiled molecules. Replicative intermediates migrating slower than form II and topoisomers migrating between forms II and I were also included among the replication products. Replication of the ors plasmids was not inhibited by ddTTP, an inhibitor of DNA polymerase beta and gamma, and was sensitive to aphidicolin indicating that DNA polymerase alpha and/or delta was responsible for DNA synthesis. Origin mapping experiments showed that early in the in vitro replication reaction, incorporation of nucleotides occurs preferentially at ors-containing fragments, indicating ors specific initiation of replication. In contrast, the limited incorporation of nucleotides into pBR322, was not site specific. The observed synthesis was semiconservative and appeared to be bidirectional.

Animals↗
PubMed1991

Establishing a self-perpetuating American Heart Association/Advanced Cardiac Life Support program in West Germany.

Sudden cardiac death is one of the major health problems in industrialized nations. The American Heart Association-sponsored Basic Life Support and Advanced Cardiac Life Support (ACLS) programs provide consensus training programs geared to teach local persons and health care providers the techniques of CPR and advanced life support, respectively. In April 1988, the staff of the U.S. Army Hospital Berlin conducted an ACLS provider course for German physicians. Fourteen students attended the first course; nine passed, and two did not complete the course. Two more courses have been completed. The enthusiasm expressed by the German physicians led to the nomination of one of the physicians for an associate faculty position, and plans for an instructor course of German physicians are under way.

American Heart Association↗
PubMed1988

Estrogen receptor and hormone responsiveness of medullary thyroid carcinoma cells in continuous culture.

We have examined the estrogen responsiveness and estrogen receptor in medullary thyroid carcinoma using a model of an established human cell line, TT. TT cells bind [3H]estradiol with high affinity. Scatchard analysis reveals a single class of binding site with a concentration of 173 fmol/10(6) cells and a dissociation constant of 2.1 x 10(-9) M, values which are comparable to those of a well established model cell line for estrogen responsiveness, MCF-7 human breast cancer cell line. Estradiol in physiological concentrations moderately stimulated TT cell proliferation, whereas in pharmacological concentrations it markedly inhibited cell growth. [3H]Thymidine incorporation into acid-insoluble material was also stimulated following a 5-day treatment with 5 x 10(-9) M estradiol. Tamoxifen at a concentration of 1 microM reduced cell proliferation by 43-48% after 5-7 days of treatment. The growth suppression induced by tamoxifen was reversed by addition of 10 nM estradiol. This is the first report of estrogen growth stimulation and tamoxifen growth inhibition of a tumor cell line derived from human medullary thyroid carcinoma.

Carcinoma↗
PubMed1988

Health promotion and health education: the emerging role of the private sector.

The climate is right for new ventures in health education, especially those in which corporate leaders join forces with other members of the communities where they do business. Working with the public sector and other members of the private sector--with schools, universities, health departments, churches, professional associations, voluntary agencies, and foundations--corporations can become a vital new force in supporting health education not only of their own employees but also of children and adults and the public at large.

Commerce↗
PubMed1987

Dual-balloon angioplasty of recoarctation of the aorta.

Percutaneous balloon angioplasty is a successful method for treating recoarctation of the aorta after surgical repair. The procedure is usually performed with small balloons on 4 or 5 French (Fr) shafts (Gruentzig or Cook) in infants or large balloons on 8 or 9 Fr shafts (Meditech or Mansfield) in older children. In certain children, however, the 8 or 9 Fr shafts may be too large for insertion in the femoral artery, and the 4 or 5 Fr shafts may not carry a balloon large enough to effectively dilate the area of restenosis. We describe a case involving a 9-kg infant in whom recoarctation of the aorta was successfully treated with two small side-by-side balloon angioplasty systems.

Journal Article↗
PubMed1982

Giant lymph node hyperplasia involving the thymus with associated nephrotic syndrome and myelofibrosis.

Giant lymph node hyperplasia (GLH) is an unusual form of benign lymphoid hyperplasia which, although it often occurs in the mediastinum, has not previously been reported to involve the thymus. In this report, a case of GLH with involvement of the thymus and with associated nephrotic syndrome and myelofibrosis is presented. The significance of the association of these conditions with GLH is discussed, including the possibility that some or all of the patient's abnormalities may have been related via an abnormal immune mechanism.

Adult↗