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Biomedical subjects

E Carlton

Publications and source records attributed to E Carlton.

11 recordsLinked to original sources
PubMed1995

Skeletal response to recombinant human growth hormone (rhGH) in children treated with long-term corticosteroids.

Corticosteroid therapy causes osteopenia and growth retardation in children; such changes are associated with diminished rates of bone formation and turnover. Since growth hormone activates bone remodeling, the biochemical and skeletal responses to rhGH were evaluated in four pediatric patients, aged 12.8 +/- 3 years, with long-term corticosteroid use (5 +/- 2 years). Recombinant human growth hormone (rhGH), 0.125 mg/kg, was given 3 times/week by subcutaneous injection for 12 months. Iliac crest bone biopsies were obtained after double tetracycline labeling before and at the end of rhGH therapy; serum levels of calcium, phosphorus, alkaline phosphatase, parathyroid hormone (intact), 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D3, osteocalcin (BGP), and insulin-like growth factor-1 (IGF-1) were measured every 3 months during the treatment period. The average dose of prednisone was 0.24 +/- 0.05 mg/kg/day initially, and this did not change during the study. Serum calcium, phosphorus, alkaline phosphatase, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D3, and BGP were unchanged during the rhGH therapy, but the serum IGF-1 level increased by 71%, p < 0.01. Eroded bone perimeter and cancellous bone area did not change significantly during rhGH therapy. Bone formation rates rose from 423 +/- 475 to 781 +/- 407 microns2/mm2/day, p < 0.05, and the length of double tetracycline-labeled bone perimeter increased by 85%, p < 0.05. The bone formation rate in the growth hormone group exceeded the values of an age-matched reference group (14.3 +/- 3 years), 780 +/- 407 microns2/mm2/day versus 411 +/- 479 microns2/mm2/day, p < 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

25-Hydroxyvitamin D 2↗
PubMed1995

Neural network prediction of nonstress test results: how often should we perform nonstress tests?

OBJECTIVE: Our purpose was to predict outcomes and optimal intervals for nonstress tests of term gravid women with neural networks. STUDY DESIGN: We studied 100 normal term patients whose 30-minute nonstress tests, performed on 5 consecutive days, were computer analyzed for the following elements: fetal heart rate baseline, variability, signal loss, accelerations (> 15 beats/min), and decelerations. The training set used 65 patients; the testing, 35 patients. Nonstress test data (days 1 to 4) were inputs; day 5 data were training patterns. Networks for each nonstress test element used Brainmaker Macintosh 1.0 (California Scientific Software, Nevada City, Calif.) trained to 0.12 tolerance. Actual fetal heart rate elements and their daily differences were compared with predictions by the networks and multiple regressions. RESULTS: There was little difference between networks using daily or alternate-day inputs for predicting test performance on day 5; networks using test intervals > 2 days could not be trained to tolerance. Long-term fetal heart rate variation was the nonstress test element best predicted. Daily differences networks provided better prediction of all day 5 data than did actual daily values networks or multiple regression formulas. CONCLUSIONS: Baseline long-term fetal heart rate variability seems to be the most predictable fetal heart rate element over time and should merit more consideration in overall fetal testing. Fetal heart rate elements are not easily predicted by any method for intervals longer than 2 days. Using longer test intervals might run a greater risk for unanticipated changes in nonstress test outcomes, even when fetal condition is normal.

Female↗
PubMed1993

Development of third-generation immunochemiluminometric assays of follitropin and lutropin and clinical application in determining pediatric reference ranges.

We developed dioxatane-based immunochemiluminometric assays (ICMAs) for lutropin (LH) and follitropin (FSH), using monoclonal antibodies. These ICMAs have a minimal detectable dose (analytical sensitivity) of 0.01 IU/L, extending the lower limit of sensitivity 10-fold (from 0.10 IU/L) when compared with immunoradiometric assays (IRMA) (second generation), and thus provide a true third-generation assay. Daytime FSH and LH concentrations were measured in 236 boys and 195 girls. Unlike the previous assays, all the samples had detectable concentrations of LH and FSH. In agreement with results from earlier methods, the present results indicate that for both sexes mean FSH and LH concentrations are relatively high during the early months of life, fall to baseline prepubertal concentrations by 12-18 months, and remain low until the onset of puberty. During puberty, the mean concentrations of FSH and LH increase significantly in both girls and boys with each stage of puberty, but there is considerable overlap between stages. These third-generation FSH and LH ICMAs reliably separate daytime plasma FSH and LH concentrations of prepubertal children from those of sexually mature children, and therefore can more reliably distinguish between the major causes of precocious puberty (e.g., gonadotropin dependent and independent). Our LH assay is also useful in monitoring the gonadotropin-releasing hormone therapy of patients with gonadotropin-dependent precocious puberty.

Adolescent↗
PubMed1992

Modified immunoradiometric assay of parathyroid hormone-related protein: clinical application in the differential diagnosis of hypercalcemia.

We have developed a sensitive, specific solid-phase immunoradiometric assay (IRMA) of parathyroid hormone-related protein (PTH-RP) with use of affinity-purified polyclonal immunoglobulins. Antibodies recognizing PTH-RP(37-74) are immobilized to a polystyrene bead to "capture" analytes from the sample; antibodies to epitopes within the 1-36 amino acid region of PTH-RP are labeled with 125I. This IRMA recognizes PTH-RP(1-74) and PTH-RP(1-86) equivalently, but does not detect N-terminal or C-terminal fragments of PTH-RP, intact human parathyrin (PTH), or fragments of PTH. PTH-RP is not stable in plasma at 3-5 degrees C or room temperature, but a mixture of aprotinin (500 kallikrein units/L) and leupeptin (2.5 mg/L) improves PTH-RP stability in blood samples. In plasma collected in the presence of these protease inhibitors from normal volunteers and patients with various disorders of calcium metabolism, PTH-RP concentrations were above normal (greater than 1.5 pmol/L) in 91% (42 of 46) of patients with hypercalcemia associated with nonhematological malignancy. In plasma from patients with other hypercalcemic conditions (e.g., primary hyperparathyroidism, sarcoidosis, and vitamin D excess), PTH-RP was undetectable. Above-normal concentrations of PTH-RP and total calcium decreased to normal in a patient with an ovarian cyst adenocarcinoma after surgical removal of the tumor. We conclude that PTH-RP is related to and probably the causative agent of hypercalcemia in most patients with cancer, and that measurements of PTH-RP are useful in the diagnosis and management of patients with tumor-associated hypercalcemia.

Aprotinin↗
PubMed1989

Rapid radioimmunoassay of circulating chromogranin A: in vitro stability, exploration of the neuroendocrine character of neoplasia, and assessment of the effects of organ failure.

Chromogranin A is a useful probe of neuroendocrine neoplasia in humans. Here we optimize a rapid, sensitive radioimmunoassay modification for detecting chromogranin A in humans and other species. The site of chromogranin A circulation is the acellular plasma; platelets contain no chromogranin A immunoreactivity. The immunoreactivity in plasma is stable to repeated freezing and thawing, prolonged incubation at 37 degrees C, and lyophilization. Venipuncture alone resulted in modest (+ 12%, P less than 0.03) increase in chromogranin A in plasma. Several classic neuroendocrine neoplasia-pheochromocytoma, carcinoid tumor, neuroblastoma, and (vasoactive intestinal polypeptide)oma-produce markedly increased chromogranin A in plasma. By contrast, subjects with malignant melanoma, renal cell carcinoma, and thymoma all had normal values for chromogranin A. Hypersecretion of human choriogonadotropin beta subunit from both malignant (choriocarcinoma) and normal (placenta) syncytiotrophoblast cells was unaccompanied by an increase in chromogranin A, a dissociation compatible with the lack of granular storage and release of syncytiotrophoblastic peptide hormones. Both hepatic and renal failure resulted in increased chromogranin A in plasma, with renal failure leading to concentrations otherwise seen only in neuroendocrine neoplasia. These observations refine the diagnostic specificity of chromogranin A in plasma.

Adult↗
PubMed1987

Autoimmune thyroid disease: an expanding spectrum.

Autoimmune thyroid disease classically has included Hashimoto's thyroiditis and Graves' disease. Hashimoto's thyroiditis probably also includes focal thyroiditis, fibrous thyroiditis, primary myxedema, and Hashitoxicosis as variants. Graves' disease is associated with ophthalmopathy and dermopathy, and recent evidence suggests that these manifestations are autoimmune phenomena as well. Other associated autoimmune disorders include idiopathic thrombocytopenic purpura and antigen-antibody complex nephritis. Nonthyroid endocrine autoimmune deficiency disorders also have been classified as part of the spectrum of thyroid autoimmune disease. With the recent recognition of the spectrum of autoimmune mechanisms and antibody types and methods to distinguish antibody functions or types, our understanding of postpartum and neonatal thyroid disorders has been advanced considerably. The spectrum of neonatal thyroid disorders in the infants of women with autoimmune disease relates to the levels and types of antithyroid antibodies acquired from the mother. Finally, there is suggestive evidence that nonspecific goiter, including simple adolescent goiter and multinodular goiter as well as some cases of sporadic cretinism, may be part of an even more expanded spectrum of autoimmune thyroid disease.

Autoimmune Diseases↗
PubMed1983

Behavioral modification in a weight-reduction program.

Previous surveys have shown a high prevalence of obesity in women of low socioeconomic status. This study confirmed the relationship in the Medical Appointment Clinic at Grady Memorial Hospital, Atlanta. Behavioral modification therapy for obesity had not been carefully tested in this type of population. Therefore, a behavioral modification group-oriented weight-reduction method was adapted for 80 participants from this setting. Eighty controls, matched for age, sex, race, and percent ideal body weight, received individualized counseling from a dietitian. Thirty-one matched pairs (62 individuals) had follow-up weights taken more than one year later. Thirteen percent (four) of the behavioral modification group participants versus 6.4% (two) of the control participants maintained a loss of 20 lb. or more during this period. The mean weight loss for the behavioral modification group was 4.6% of their ideal body weight versus 0.9% for the control group. The results of the behavioral modification program were statistically superior to those of the control program (p = 0.058). Overall, for participants whose mean weight was 241 lb., it is difficult to conclude that a mean 5-lb. weight loss represents a meaningful change or that this weight loss was due to behavioral modification. The results of this program among low socioeconomic status women, however, were comparable with the results of similar large, free-living programs among middle class participants.

Adult↗
PubMed1979

A computer program for Wiener filtering of evoked potential data.

We have developed a computer program for Wiener filtering of evoked potential data. The basic algorithm involves computation of the difference berween the power spectrum of the sweep sum and the sum of power spectra of individual sweeps. Power spectra are computed by means of the discrete Fourier transform. The program is now being run on a LSI-11 computer in a neurophysiology research laboratory to analyze somatic evoked potential data from monkeys.

Animals↗