Biomedical subjects

M W Ashcraft

Publications and source records attributed to M W Ashcraft.

6 recordsLinked to original sources

PubMed1984

Cyclic Cushing's syndrome.

Cyclic Cushing's syndrome is a rare but increasingly recognized disorder of periodic fluctuations of adrenal steroid production. A case of cyclic Cushing's syndrome due to a pituitary adenoma is described. The patient demonstrated a prolonged cycle length of approximately six months, during which a spontaneous remission occurred both clinically and biochemically. Previously documented cases of cyclic Cushing's syndrome are reviewed, and the pitfalls in interpretation of results of dexamethasone suppression testing in the presence of spontaneous fluctuations in cortisol production are discussed.

Adult↗

PubMed1983

A unique growth factor in patients with acromegaloidism.

Acromegaloidism is a syndrome characterized by features of acromegaly without biochemical evidence of excessive GH or somatomedin production. We searched for a growth factor in the serum of patients with this syndrome. Growth-promoting activity was measured by determining the stimulatory effect of whole and fractionated serum on colony formation by human erythroid progenitors in vitro. Sera from five subjects with acromegaloidism gave a mean (+/- SEM) stimulated colony growth of 211 +/- 4.0 colonies, in contrast to normal sera which yielded a mean colony growth of 100 +/- 11.0 (n = 9; P less than 0.001). When serum was chromatographed on a Sephadex G-200 column, the maximal stimulation of colony growth was found in the fractions coinciding with the descending slope of the second protein peak. Based on gel filtration chromatography, the estimated molecular weight was 70,000 daltons. Epidermal growth factor, nerve growth factor, fibroblast growth factor, and platelet-derived growth factor resulted in no substantial stimulation of colony growth under the conditions used. Although the erythroid progenitor cells of a Laron dwarf were unresponsive to 200 ng/ml human GH, they were clearly stimulated by serum from a patient with acromegaloidism. The present study describes the presence of a heretofore unidentified growth factor in the serum of subjects with acromegaloidism. This factor also stimulated the erythroid precursor cells of a Laron dwarf whose cells were unresponsive to GH. The physiological role of this growth factor in normal man as well as its pathogenic role in subjects with acromegaloidism remain to be established.

Acromegaly↗

PubMed1982

Serum cortisol levels in Cushing's syndrome after low- and high-dose dexamethasone suppression.

To standardize the cutoff points of serum cortisol values in the evaluation of Cushing's syndrome during a low- and high-dose dexamethasone suppression test, daily serum cortisol measurements (0800 hours and 1600 hours) and urinary 17-hydroxycorticosteroids were compared (Study A). Forty-seven subjects were studied (11 normal subjects, 15 patients with Cushing's disease, five patients with adrenal adenoma, and 16 subjects with suspected Cushing's syndrome). A serum cortisol measurement at 1600 hours of more than 5 micrograms/dL on low-dose dexamethasone suppression and more than 10 micrograms/dL on high-dose dexamethasone were ascertained to be nonsuppressed values. A baseline dehydroepiandrosterone-sulfate value less than 0.4 microgram/mL indicated patients with an adrenocorticol adenoma. Study B was a prospective study of 17 patients in which no urine samples were collected. Serum cortisol levels, obtained in 1600 hours on the second day of low- and high-dose dexamethasone, accurately allowed a differential diagnosis of suspected Cushing's syndrome. Serum cortisol measurements can replace the urinary 17-hydroxycorticoid measurements in a cost-effective manner without a decrease in the degree of accuracy.

17-Hydroxycorticosteroids↗

PubMed1981

The comparative value of serum thyroglobulin measurements and iodine 131 total body scans in the follow-up study of patients with treated differentiated thyroid cancer.

This study is an attempt to unify the evaluation of patients with well-differentiated thyroid cancer after ablative therapy. As such serum thyroglobulin determinations on and off thyroid hormone (T4) therapy and iodine 131 total body scans were examined in 53 patient studies. No metastases were found in patients whose thyroglobulin value was undetectable (less than 1 ng/ml). Values during T4 therapy that were detectable, even as low as 4.2 ng/ml, were occasionally associated with metastases. After T4 withdrawal, thyroglobulin value and scan were obtained. Neither metastasis nor clinically detectable cancer was found in patients whose thyroglobulin value was less than 10 ng/ml while off T4. Conversely, a value greater than 10 ng/ml was often associated with documented metastases even when the scan was negative. In summary, a thyroglobulin value less than 1 ng/ml during T4 therapy or less than 10 ng/ml off T4 therapy suggests successful therapy and a routine scan could be avoided unless clinically indicated. However, a value greater than 10 ng/ml suggests the presence of metastasis despite a negative scan. Thyroglobulin determination substantially improves the management of these patients.

Adolescent↗

PubMedDate not supplied

Management of thyroid nodules. I: History and physical examination, blood tests, X-ray tests, and ultrasonography.

The approach to the management of the thyroid nodule remains controversial. Confusion exists because virtually any thyroidal disease can present as a clinically solitary nodule which means there is no uniformity regarding natural history, incidence, prevalence, epidemiology, and pathophysiology.. The variety of definitions of thyroid nodules and thyroid carcinoma and the different modes of study selection and individual bias add to the confusion. Diagnostic approaches have not yielded a completely reliable technique to differentiate benign from malignant thyroidal disease. A history of neck irradiation of cervical lymphadenopathy significantly increases the chance of thyroid malignancy, but other parameters of the history or physical examination as well as blood tests are unreliable. Ultrasound displays anatomic but not histologic features. X-ray techniques (plain films, computed tomographic scans, xeroradiography, chest x-ray, barium swallow, lymphography, and angiography) have been used to visualize thyroid nodules, with some techniques proving more useful than others.

Diagnosis, Differential↗

PubMedDate not supplied

Management of thyroid nodules. II: Scanning techniques, thyroid suppressive therapy, and fine needle aspiration.

For the differentiation of benign from malignant thyroidal disease, ultrasound displays anatomic but not histologic features. Other visualization techniques can be used including isotope scanning (radioiodine, 99m technetium, 241 americium fluorescence, 131 cesium, 67 gallium, 75 selenomethionine, 201 thallium, 32 phosphorus, 99m Tc-bleomycin, 197 mercury, 133 xenon), thermography, x-ray techniques (plain films, computed tomographic scan, xeroradiography, chest x-ray barium swallow, lymphography, angiography), and thyroid hormone suppression. Needle biopsy can be done by core biopsy (Vim-Silverman and drill biopsy), large needle biopsy for histologic processing and fine needle aspiration for cytologic interpretation. The latter is the safest, most reliable, and most cost-effective technique currently available to differentiate between benign and malignant thyroidal disease and has great promise for the future.

Americium↗