Search PubMed⌕ Search

Biomedical subjects

C A Gorman

Publications and source records attributed to C A Gorman.

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

Volume measurements of normal orbital structures by computed tomographic analysis.

Computed tomographic digital data and special off-line computer graphic analysis were used to measure volumes of normal orbital soft tissue, extraocular muscle, orbital fat, and total bony orbit in vivo in 29 patients (58 orbits). The upper limits of normal for adult bony orbit, soft tissue exclusive of the globe, orbital fat, and muscle are 30.1 cm3, 20.0 cm3, 14.4 cm3, and 6.5 cm3, respectively. There are small differences in men as a group compared with women but minimal difference between right and left orbits in the same person. The accuracy of the techniques was established at 7%-8% for these orbit structural volumes in physical phantoms and in simulated silicone orbit phantoms in dry skulls. Mean values and upper limits of normal for volumes were determined in adult orbital structures for future comparison with changes due to endocrine ophthalmopathy, trauma, and congenital deformity.

Adult↗
PubMed1984

[75Se]Selenomethionine scanning for parathyroid localization should be abandoned.

Image subtraction techniques, in conjunction with [75Se]selenomethionine (75Se) scintigraphy, have recently been suggested to be a potentially valuable tool for localization of parathyroid abnormalities. With use of these techniques, we prospectively studied 15 patients scheduled for parathyroid operations. Postoperatively, all were normocalcemic. Anterior scintiscans of the neck were divided into quadrants, and regions of enhanced uptake were assigned to one or more quadrants. On this basis, by chance alone a minimum of 25% of single-gland enlargements would be assigned to the correct quadrant of the neck. We found that by use of 75Se scanning only 8 of 22 abnormal glands (36%) were assigned to the quadrant of the neck in which they were found intraoperatively. In no case was a clearly visualized focus of parathyroid activity encountered. These results do not justify the continued use of 75Se scintigraphy with or without image subtraction in the preoperative localization of parathyroid glands.

Adenoma↗
PubMed1984

L-thyroxine contamination of pharmaceutical D-thyroxine: probable cause of therapeutic effect.

Studies have shown that pharmaceutic preparations of the stereo isomers of thyroxine differ with respect to thyromimetic potency and lipid level-lowering effects. We applied a stereospecific assay for dextrothyroxine (DT4) and levothyroxine (LT4) to determine whether the biologic effects observed after the administration of DT4 (Choloxin; Flint Laboratories) resulted from inherent biologic activity of DT4, conversion of DT4 to LT4 in vivo, or LT4 contamination of Choloxin tablets. Choloxin was administered in a dose of 8 mg/day for 5 mo to nine athyreotic subjects who were then treated with pharmaceutic LT4 (Synthroid), 0.2 mg/day for an additional 5 mo. Analysis showed that LT4 contamination of Choloxin tablets ranged from 0.50% to 2.30%. This degree of contamination resulted in physiologically significant doses of LT4 in the 8 mg/day doses of Choloxin. During the treatment with two different lots of Choloxin, serum LT4 accounted for 33% to 53% of the measurable serum total thyroxine. The degree of LT4 contamination in Choloxin tablets was sufficient to account for the observed serum LT4 levels and casts doubt on the conclusions derived from previous studies in which Choloxin was used as the source of "DT4."

Adolescent↗
PubMed1983

Computed tomographic scanning versus radioisotope imaging in adrenocortical diagnosis.

Referral patterns from internists to departments of nuclear medicine or radiology are important determinants of whether adrenal glands are imaged by computed tomography (CT) or by radioisotope scintigraphy. To assist clinicians in making an informed choice, computed tomographic scans were compared with isotope scintigrams using 131I-19-iodocholesterol (19-IC) and 131I-6 beta-iodomethyl-19-norcholesterol (NP-59). In general, imaging techniques serve to localize diseases that are diagnosed on the basis of biochemical tests of adrenal function. Computed tomographic scanning and NP-59 scanning are of comparable diagnostic accuracy. Both are superior to 19-IC scanning in the diagnosis of Cushing's syndrome and primary aldosteronism. Computed tomographic scanning is faster and less expensive, and involves lower radiation doses to the patient than scintigraphy. Adrenocortical isotope scanning as a routine procedure has been superseded by computed tomographic scanning at the Mayo Clinic.

19-Iodocholesterol↗
PubMed1983

Outcome of anesthesia and surgery in hypothyroid patients.

We retrospectively examined the outcome of anesthesia and surgery in 59 hypothyroid patients and in 59 paired euthyroid matched controls. Hypothyroid patients had more preoperative risk factors but did not differ as a group from controls with regard to duration of surgery or anesthesia, lowest temperature and BP recorded during surgery, need for vasopressors, time to extubation, fluid and electrolyte imbalances, incidence of arrhythmias, pulmonary and myocardial infarction, sepsis, need for postoperative respiratory assistance, bleeding complications, or time to hospital dismissal. Analysis of subsets of hypothyroidism (thyroxine level, less than 1.0, less than 3.0, and greater than or equal to 3.0 micrograms/dL) also failed to disclose any significant differences compared with matched controls. Among patients with mild or moderate hypothyroidism, we found no evidence to justify deferring needed surgery until the hypothyroidism has been corrected.

Anesthesia↗
PubMed1983

Temporal relationship between onset of Graves' ophthalmopathy and diagnosis of thyrotoxicosis.

During preoperative examination of 194 patients scheduled for orbital decompression for Graves' ophthalmopathy, it was noted that 29 had never been clinically hyperthyroid. These patients did not differ appreciably from those who had had hyperthyroidism, in terms of age distribution, sex ratio, presenting eye manifestations, or rate of progression of ophthalmopathy. In 81% of the patients with hyperthyroidism, the date of the first eye manifestations was symmetrically distributed within 18 months before or after the time when hyperthyroidism was diagnosed. These observations do not support the viewpoint that radioiodine therapy or surgical intervention initiates the ophthalmic process. The observations focus attention on the need for etiologic theories to address the usually close linkage between thyrotoxic and ophthalmic expressions of Graves' disease rather than on the exceptions to a general rule.

Adolescent↗
PubMed1982

Radioiodine-induced hypothyroidism in Graves' disease: factors associated.

A retrospective analysis was done of the records of 454 patients who received their first I-131 treatment for Graves' disease during six periods covering 1951 to 1978. In the earliest group, 3% of patients were hypothyroid 3 mo after I-131 use, and 40% were hypothyroid at 1 yr. In the most recent group, 36% of patients were hypothyroid at 3 mo and 91% were myxedematous at 1 yr. Although no obvious trends were noted, whether in the number of patients pretreated with thionamide drugs, in the mean 24-hr I-131 uptake, or in the calculated dose of I-131 (muCi/estimated gram of thyroid tissue) during the years of the study, the initial mean dose of I-131 administered increased from 8.1 mCi in the earliest group to 13.8 mCi in the latest group. Concurrently, estimates of gland size increased from a mean of 26 g in the first group to 43 g in the last. If, in patients with Graves' disease, the thyroid gland size did not truly increase during the years of the study, the increasing occurrence of early hypothyroidism seen after I-131 use may reflect the conscious or unconscious decision to use larger doses of I-131 calculated on the basis of inflated estimates of thyroid gland weight.

Adult↗
PubMed1981

Simultaneous determination of D- and L-thyroxine in human serum by liquid chromatography with electrochemical detection.

A method for the determination of D- and L-thyroxine in human serum is described. The method involves extraction of thyroxine from serum and the separation of thyroxine enantiomers on a reversed-phase, high-performance liquid chromatographic column by use of a chiral eluent containing L-proline and cupric sulfate. Satisfactory resolution of the enantiomers of thyroxine, triiodothyronine, and reverse triiodothyronine can be achieved in 12 min and, employing amperometric detection to monitor the separation, the detection limit for serum thyroxine is in the range of 1--3 ng per injected sample.

Chromatography, High Pressure Liquid↗
PubMed1980

Gastric, pancreatic, and biliary responses to meals in hyperthyroidism.

Upper gastrointestinal function in response to a mixed nutrient meal was evaluated in hyperthyroid patients, both before and after therapy, and in healthy controls. Gastric secretion, gastric emptying, and pancreatic secretion were all normal and normally integrated postprandially in the hyperthyroid patients. Bile acid output was reduced (P less than 0.05) in this group of patients relative to healthy controls. Duodenal bile acid concentrations, however, were above the critical micellar concentration in most of the hyperthyroid patients, and the bile acid output and concentration remained unchanged in all patients three months after treatment. After radioactive iodine therapy, when gastrointestinal symptoms were returning toward normal, a small but statistically significant increase in gastric secretion was observed. However, gastric emptying and pancreatic secretion, like biliary secretion, remained unchanged. Abnormalities responsible for the diarrhoea and steatorrhoea in hyperthyroidism appear to reside primarily distal to the duodenum. However, reduced bile acid output may be a contributory factor in some patients.

Adult↗
PubMed1979

Comparative effectiveness of dextrothyroxine and levothyroxine in correcting hypothyroidism and lowering blood lipid levels in hypothyroid patients.

Data reported here establish that treatment regimens of 4 mg dextrothyroxine and 0.15 mg levothyroxine in hypothyroid subjects produce similar degrees of lowering of serum TSH, cholesterol, triglycerides, and phospholipid levels and equal stimulation of metabolic rate. The Murphy-Pattee total T4 determination applied to blood samples drawn 24 h after the last dose of dextrothyroxine can be used to assess adequacy of treatment. Correction of hypothyroidism requires high serum levels of dextrothyroxine than of levothyroxine. Serum T3 levels increase in patients treated with dextrothyroxine. In the treatment of hypothyroidism, the cholesterol-lowering and metabolic rate-stimulating effects of dextrothyroxine do not appear to be dissociated. Further studies are needed to determine whether such an effect can be demonstrated in euthyroid hypercholesterolemic subjects with doses established herein as equivalent in terms of the stimulating effect on metabolic rate.

Basal Metabolism↗
PubMed1978

Thyrotropin receptors in normal and pathological human thyroid tissues.

The properties of TSH receptors in normal and pathological human thyroid tissues were studied. Highly purified bovine TSH after lactoperoxidase iodination retained full biological activity, as assessed by radioreceptor assay. Binding of bovine [125I]TSH to 1000 x g pellets of human thyroid homogenate was specific with respect to hormone and tissue. Total binding amounted to 50-60% of total radioactivity using 10 mg (wet weight) normal thyroid tissue. Nonspecific binding was only 6% of total radioactivity. Normal thyroid tissue contained two orders of binding sites, which were shown to be independent of each other by Hill plot analysis. The high affinity sites [equilibrium dissociation constant (Kd), 0.015-0.16 x 10-9 M] were present in concentrations of 1.05-9.30 pmol/mg protein and concentrations of low affinity sites (Kd, 1.2-2.4 x 10-9 M) were 35.9-213 pmol/mg. In all pathological thyroid tissue studied, two orders of binding sites were found with dissociation constants similar to those of normal tissues, but the number of binding sites was markedly reduced. Both orders of binding sites in solitary "cold" adenomas and only the low affinity sites in thyroid tissue from patients with Graves' disease were significantly reduced in number (P less than 0.01). There was a questionable decrease in high affinity sites in the Graves' tissue (P = 0.05). We have found the definite presence but a decreased number of binding sites in both orders of receptors in papillary and follicular carcinomas. There were few or no binding sites in medullary carcinoma.

Adenocarcinoma↗
PubMed1978

Rectilinear thyroid scanning as a predictor of malignancy.

Rectilinear scan findings were correlated with the surgically documented size, location, and histology of thyroid carcinoma in 67 patients. At the site of the carcinoma, 36 (54%) had hypofunction, associated with a palpable abnormality in all but one patient; 16 (24%) had an abnormality on palpation but not on scanning; 11 (16%) had both a normal clinical examination and a normal scan, associated with a benign abnormality in another part of the thyroid; and four (6%) had a patchy uptake. A literature review established that use of the gamma camera with pinhole collimator does not increase the specificity of carcinoma predictability, despite the enhanced sensitivity. The scan may still be used in evaluating the clinically solitary nodule that is not obviously malignant. However, unless that module is hyperfunctioning, clinical criteria rather than appearance of the scan should contribute most to the decision of whether to treat surgically.

Diagnostic Errors↗
PubMed1978

Radiation dose in the selection of 131I or surgical treatment for toxic thyroid adenoma.

Clinicians, by their patterns of referral to colleagues in nuclear medicine or surgery, may strongly influence the selection of 131I versus surgical treatment for patients with toxic thyroid adenoma. The information presented here is intended to aid them in making an informed choice. As nodule size of an adenoma increases from 2 cm to 6 cm, the amount of radioiodine administered to the patient to deliver the same dose (30 000 rads to the nodule center, assuming a 30% uptake) increases from 5.6 mCi to 135 mCi. Concurrently, the suppressed thyroid tissue receives a radiation dose as high as 2300 rads. Despite these potentially carcinogenic doses, few patients with radioiodine-induced thyroid tumors have been reported; we discuss possible reasons for this. For young patients with large nodules, surgery is preferred.

Adenoma↗
PubMed1978

Incidence of malignant neoplasms of all types of patients with Graves' disease.

The incidence of malignancy among patients with Graves' disease who were residents of one Minnesota county was examined in 342 patients between 1935 and 1967. During 4,736 person-years of observation, 32 malignancies were diagnosed; 24 cases were expected and the difference is not significant. Four cases of breast carcinoma were found vs five expected. Other tumor sites were cervix (five), uterus (two), rectosigmoid colon (three), stomach (two), larynx (two), and lung (two). There were three cases of leukemia, and in nine other sites one cancer each was recorded. There was a slightly higher than expected incidence of malignancy in patients who had received 131I therapy; this finding requires further study in a larger patient population. Among patients who received thyroid hormone, the observed incidence of breast cancer was not significantly different from the expected incidence in our population.

Adolescent↗