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Biomedical subjects

L Hanford

Publications and source records attributed to L Hanford.

8 recordsLinked to original sources
PubMed1992

A simple bioassay for epidermal growth factor using pig thyrocytes.

A bioassay for epidermal growth factor (EGF) is described using an eluted stain assay (ESTA) of dehydrogenase activity in pig thyrocytes. Optimal responsiveness to EGF was obtained in confluent cultures of primary pig thyrocytes cultured with EGF or biological samples containing EGF for either 24 or 48 h. Dehydrogenase activity was determined by measuring the production and then the release of a coloured formazan product produced by reduction of a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide substrate added to the cells. The assay responded equally to mouse, human and recombinant EGF and was suitable for measuring EGF activity in some but not all biological fluids. Specificity of detection of EGF activity was confirmed using antibody to EGF. The ESTA assay compared favourably with the radioreceptor assay for EGF in terms of sensitivity to EGF with half-maximal activation at 0.24 +/- 0.06 nmol/l (mean +/- S.E.M., n = 22 experiments) for the ESTA assay and 0.60 +/- 0.13 nmol/l (n = 7 experiments) for the radioreceptor assay.

Animals↗
PubMed1990

The secretory characteristics of epidermal growth factor in human saliva.

A series of unstimulated and stimulated saliva samples from healthy volunteers was tested for EGF by radioimmunoassay. Salivary EGF, like other salivary constituents, was secreted in a diurnal pattern. On stimulation the rate of EGF secretion doubled but the concentration fell by 70% because of dilution by salivary fluid. EGF secretion was positively related to saliva flow (p = 0.00001) but the coefficient of correlation was low (r = 0.47). Over a period of 30 min continual salivary stimulation, EGF was released in a bimodal pattern with peaks occurring at 3 and 12 min. Subsequently, EGF secretion remained stable at a rate of release that was approx. 80% of the initial peak value (7.4 ng/min). Chromatography indicated that both high and low molecular-weight forms of EGF were present in unstimulated and stimulated saliva and that the low-weight form predominated. However, the proportion of high molecular-weight EGF increased from 18 to 38% of the total on short-term (3 min) stimulation.

Adolescent↗
PubMed1988

Extracellular calmodulin and its association with epidermal growth factor in normal human body fluids.

In this study we describe the occurrence of a calmodulin-like protein in normal human biological fluids. Extraction of the calmodulin-like protein from breast milk, saliva, serum and urine provided an extract with enhanced calmodulin immunoreactivity which, in the case of milk and saliva, showed a protein band comigrating with authentic calmodulin (Mr 17,000) on sodium dodecylsulphate-polyacrylamide gel electrophoresis. However, in milk, saliva and serum a major protein band of Mr 14,000-15,000 was always observed, which we speculate may be related to calmodulin, possibly as a partially degraded form. Estimates of biologically active calmodulin in most normal extracellular fluids were of the order which we have found will stimulate cell division when added to the extracellular medium of cells in culture. Levels ranged from 0.03 nmol/l in urine to 18.6 nmol/l in breast milk, and exhibited a quantitative relationship (r = 0.79, P less than 0.01) to epidermal growth factor (EGF) levels in fluids. Where EGF concentrations varied from normal (increased in saliva 24 h after oral surgery and reduced in the urine of patients with renal failure) calmodulin concentrations were similarly affected. The presence of calmodulin in serum may in part be attributable to its release from platelets which are particularly rich in calmodulin. Release of calmodulin from the platelet was associated with that of EGF and other platelet products.

Blood Platelets↗
PubMed1981

The prediction of relapse after drug treatment of Graves' disease by assay of long acting thyroid stimulator-protector (LATS-P).

In a study of fifty-two patients with Graves' disease followed for 1 year after stopping antithyroid drugs, a strong relationship has been found between serum LATS-P and relapse. In those with serum LATS-P activity on stopping therapy, twenty-one (88%) out of twenty-four relapsed. In those with no LATS-P activity on stopping antithyroid drugs only eight (29%) out of twenty-eight relapsed and in five LATS-P was detectable at relapse. The overall prevalence of positive assays for LATS-P at relapse (90%) was similar to that seen in untreated Graves' disease.

Adolescent↗
PubMed1981

Long-acting thyroid stimulator (LATS) and long acting thyroid stimulator protector (LATS-P) in untreated thyrotoxicosis.

The prevalence of serum LATS and LATS-P in untreated Graves' disease has been studied in eighty-three patients with thyroid overactivity; twelve (14%) were found to have significant levels of LATs and LATS-P whilst fifty-nine (72%) had significant levels of LATS-P alone. Twelve (14%) had neither activity. There was a very wide range in both activities. LATS was invariably found in association with a significantly greater concentration of LATS-P. There was no correlation between LATS-P and thyroid mass, as estimated from scintiscanning, thyroidal radioiodine uptake at 4 and 48 h, total serum T4 and total serum T3. Neither LATS nor LATS-P were detected in eleven patients with toxic multinodular goitre nor four with solitary toxic adenoma.

Adolescent↗
PubMedDate not supplied

Ethics and disability.

By using principlism to teach ethics, we are reinforcing a sense of professional superiority among health care professionals. If we are to adequately serve not just the disabled, but all those who come to us for care, we need to rethink and restructure ethics teaching to create a learning environment that promotes and enhances caring.

Persons with Disabilities↗
PubMedDate not supplied

Time of transition.

Explore the source record for details and available documents.

Activities of Daily Living↗