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Biomedical subjects

C MacLeod

Publications and source records attributed to C MacLeod.

At least 73 records · Page 4Linked to original sources
PubMed1985

A direct radioimmunoassay for human epidermal growth factor receptor using 32P-autophosphorylated receptor.

A simple and reproducible radioimmunoassay of the epidermal growth factor (EGF) receptor which uses 32P-labeled EGF receptor and anti-receptor monoclonal antibodies is reported. In vitro phosphorylation of A431 cell membranes with [gamma-32P]ATP in the presence of 20% dimethyl sulfoxide (which stimulates autophosphorylation of the EGF receptor) and 10 microM Na3VO4 (a potent inhibitor of phosphotyrosyl protein phosphatase) provides radiolabeled EGF receptor for radioimmunoassay without further purification. The most selective phosphorylation of the EGF receptor is achieved at ATP concentrations of 0.1-0.2 microM, which corresponds to the reported Km value for the autophosphorylation reaction of the EGF receptor (W. Weber, P.J. Bertics, and G.N. Gill, 1984, J. Biol. Chem. 259, 14631-14939). The incorporation of 32P into EGF receptors increases in proportion to the increase of ATP concentration up to 6 mol of labeled phosphate at 2.0 microM ATP. The label is entirely on tyrosine residues. The cell membranes can be stored at -70 degrees C for 3 months without loss of immunoreactivity and autophosphorylating activity. Standard curves for the radioimmunoassay were constructed employing either A431 cell membranes or whole cell homogenates containing a known amount of EGF receptor. The assay can detect 7 X 10(10) EGF receptor molecules or 20 ng of the receptor protein, and can quantitatively distinguish the difference in EGF receptor numbers between A431 cells and 29E2 and KB cells with 10-fold and 15-fold fewer receptors than A431 cells, respectively. 29E2 cells and KB cells express twofold more immunoreactive EGF receptors than EGF-binding sites. In contrast, A431 cells possess the same number of immunoreactive sites and receptor sites for EGF binding. To assess total EGF receptor expression, it is necessary to use a method which detects EGF receptors regardless of their intrinsic kinase activity, or capacity to bind EGF. This radioimmunoassay detects immunoreactive receptor molecules, even those which do not bind EGF.

Adenosine Triphosphate↗
PubMed1985

Visual feedback of vocal intensity in the treatment of hysterical aphonia.

This case report describes the successful though temporary removal of a hysterical aphonic symptom in a 49-year-old male patient by using visual feedback of changes in vocal intensity. Following symptom removal the patient experienced considerable emotional distress due to a number of factors. His aphonia returned and has proven resistant to subsequent intervention. At a 1-year follow-up his condition was found to be unchanged. The case is discussed in relation to the common controversy over the wisdom of symptomatic treatment for hysterical reactions, and a practical means of resolving the disagreement is considered.

Aphonia↗
PubMed1983

Intestinal myiasis.

With international travel increasing to more rural areas, physicians must be aware of the accidental ingestion of fly ova from contaminated food, which results in the fecal passage of these nondigestible eggs. The purpose of this report is to review this entity.

Adult↗
PubMed1982

Herpes zoster: complications pathogenesis and pathology. The specialist view.

The term herpes zoster is derived from the Greek herpes: to creep and zoster: a belt or girdle. Shingles is from the Latin cingere: to gird, which was corrupted to mean a belt of girdle for the human form. A typical attack of herpes zoster is usually not difficult to recognise, but it is important to be aware of uncommon manifestations and complications.

Age Factors↗
PubMed1976

Isolation and characterization of a unique glycoprotein from lavage of chicken lungs and lamellar organelles.

A major glycoprotein with an estimated molecular weight by sodium dodecylsulfate-acrylamide gel electrophoresis of 36,000 daltons has been found in lavage material of normal chicken lung. Amino acid and carbohydrate analyses of this glycoprotein indicated the presence of hydroxyproline, a high percentage of glycine, sialic acid, mannose, galactose, fucose, and glucosamine. Threonine is the NH2-terminal residue of the glycoprotein. A similar glycoprotein of the same molecular weight, NH2-terminus, amino acid, and carbohydrate composition has been found in lamellar organelles isolated from normal chicken lung. The data indicate that this unique collagen-like glycoprotein, which is similar to a major alveolar glycoprotein found in mammals, including patients with alveolar proteinosis, is also a major protein of avian airways. Because avian airways contain no Clara, ciliated, or goblet cells but do contain type II cells as the only secretory airway cells with lamellar organelles, it is likely that in birds this glycoprotein may be a product of type II cells.

Amino Acids↗
PubMed1974

Practical concepts of drug absorption, distribution and loss.

Serum concentrations of ampicillin were measured following administration of the drug orally and intravenously to nine normal volunteers. The results were analysed by graphic methods, and the effects of absorption, distribution and loss on the time serum concentration curve are discussed.

Administration, Oral↗
PubMed1972

Comparative bioavailability of three brands of ampicillin.

The relative biological availability (bioavailability) of three brands of ampicillin trihydrate capsules marketed in Canada was studied by means of a crossover experimental design and was evaluated by analysis of variance. After administration of a single oral dose (500 mg.) to volunteer subjects, the mean peak ampicillin serum concentration and the area under the time ampicillin serum concentration curve (AUC) were higher for one of the products than for the other two. A second study utilizing the same experimental design revealed no differences in these parameters when different production lots of the more available product were compared. Product bioavailability was not related to the in vitro dissolution time of the capsules. The experimental design and methods of statistical analysis are discussed.

Adult↗