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Biomedical subjects

R A Dickey

Publications and source records attributed to R A Dickey.

13 recordsLinked to original sources
PubMed2001

An Association Between Varying Degrees of Hypothyroidism and Hypercholesterolemia in Women: The Thyroid-Cholesterol Connection.

Evidence of an association between subclinical hypothyroidism and cardiovascular disease is mounting. The impact of thyroid hormone on lipid levels is primarily mediated through triiodothyronine (T(3))-bound thyroid protein binding and activation of the promoter regions of the low-density lipoprotein receptor and 3-hydroxy-3-methylglutaryl coenzyme A-reductase genes, leading to a reduction in serum cholesterol levels. Thus, the decreased T(3) seen in hypothyroidism may result in increased serum cholesterol. Although a clear correlation exists between overt hypothyroidism and clinically significant hypercholesterolemia, there is a logarithmic relationship between thyroid-stimulating hormone and cholesterol, and the effects of subclinical hypothyroidism on cardiovascular disease are under debate. However, current data suggest that normalizing even modest thyroid-stimulating hormone elevations may result in improvement in the lipid profile. (c)2001 CHF, Inc.

Journal Article↗
PubMed1982

Quantitation of biliary excretion of drugs in man.

An experimental model was developed to allow extended investigation (up to3 days) of the kinetics of upper gastrointestinal elimination (including enterohepatic recirculation) of drugs or metabolites in normal subjects under near physiologic conditions. The test drug (100 mg carprofen) was given by mouth or through a triple-lumen nasogastric tube to the upper duodenum to three normal subjects. The amounts of drug and metabolite passing the gastrointestinal aspiration port for each time interval were calculated from the concentrations measured in the aspirate using dual nonabsorbable markers and continuous sampling and reinfusion of intestinal fluids. Crossover studies without intubation in the same subjects and comparisons to historical controls demonstrated that the intubation procedure did not affect normal kinetic data obtained from conventional blood and urine specimens. The model permits direct comparison of gastrointestinal-biliary clearance with renal and with total body clearance and is particularly useful in resolving kinetic questions of gastrointestinal-biliary excretion or recirculation of metabolites when a drug must be taken by mouth. Potential first-pass phenomena may also be investigated by means of incremental gastrointestinal clearance values.

Adolescent↗
PubMedDate not supplied

Practical application of recombinant thyrotropin testing in clinical practice.

OBJECTIVE: To review the indications for use of recombinant thyrotropin (rTSH) and outline the details of implementation of rTSH diagnostic testing in patients with treated thyroid cancer. METHODS: We discuss the results of published clinical trials that have compared rTSH-stimulated testing with conventional withdrawal of thyroid hormone suppressive therapy. Appropriate candidates for rTSH testing are described, and the typical schedule for rTSH testing and follow-up is presented. An overview of coding and documentation for reimbursement is also provided. RESULTS: Clinical studies have found no significant difference in the combined sensitivity of (131)I scans and serum thyroglobulin measurements for detection of recurrent thyroid cancer after rTSH stimulation versus withdrawal of thyroid hormone therapy. As expected, patients have fewer symptoms and a more favorable mood state after use of rTSH. Patients with thyroid cancer who have undergone total or near-total thyroidectomy followed by 131I ablation can be considered for rTSH testing. For low-risk patients, two cycles of rTSH testing 1 to 2 years apart, followed by testing every 3 to 5 years, are recommended. For moderate- to high-risk patients who have undergone one cycle of negative levothyroxine-withdrawal testing, two cycles of rTSH testing at a 6- to 12-month interval, followed by testing every 1 to 3 years for at least the first decade of follow-up, are recommended. Most commercial insurance, Medicare, and Medicaid carriers now cover rTSH, either in a prescription drug plan or under major medical benefits. CONCLUSION: Radioiodine scanning and serum thyroglobulin measurement after intramuscular injection of rTSH are valuable new monitoring options in patients with treated thyroid cancer, avoiding the adverse effects of hypothyroidism.

Clinical Trials as Topic↗
PubMedDate not supplied

Lifestyle modifications in the prevention and treatment of hypertension.

OBJECTIVE: To present an objective, evidence-based review of the current literature on the role of lifestyle factors in hypertension. METHODS: We discuss the reported roles of obesity and overweight, nutritional factors, alcohol, physical activity, and smoking in the prevention and treatment of hypertension. RESULTS: For all age-groups and in both sexes, cross-sectional and prospective studies have shown a direct strong relationship between weight and blood pressure. In general, overweight is associated with a twofold to sixfold increase in the risk of developing hypertension. Clinical trials have proved that weight loss is effective in the primary prevention of hypertension as well as in the reduction of both systolic and diastolic blood pressure in patients with normal or high blood pressure. A decreased intake of dietary sodium has been demonstrated to have a hypotensive effect, both alone and as an adjunctive measure to pharmacologic therapy. Although no consensus currently exists about the role of potassium intake in prevention or control of hypertension, some studies support the protective value of high intake of potassium. A consistent relationship has been noted between consumption of alcohol and increased blood pressure, and reduced intake of alcohol has been shown to decrease blood pressure significantly. An inverse relationship exists between blood pressure and physical activity, independent of overweight or obesity. Moreover, increased physical activity helps lower both systolic and diastolic blood pressure. In a study of the effect of smoking and use of smokeless tobacco in healthy middle-aged men, ambulatory diastolic blood pressures were increased in both smokers and smokeless tobacco users in comparison with nonusers. CONCLUSION: Ample evidence supports the beneficial effects of healthful lifestyle modifications in the prevention and management of hypertension. Therefore, physicians should be motivated to provide guidance to the population relative to lifestyle practices that can help prevent and control hypertension.

Alcohol Drinking↗
PubMedDate not supplied

Diagnosis and procedure coding for bone mass measurement.

OBJECTIVE: To provide background information and practical advice about coding for submission of claims for reimbursement for performing bone mass measurement studies. METHODS: The current procedural terminology (CPT) codes for diagnoses and procedures related to reduced bone mass and osteoporosis are reviewed, and Medicare and other payer policies are discussed. RESULTS: Although considerable differences exist in payer policies relative to bone mass measurement, notable consistency is developing for Medicare patients. The CPT codes for pertinent outpatient and inpatient services, and applicable CPT modifiers, are outlined. In addition, examples are provided of criteria imposed for qualification for coverage. If a carrier or payer is not expected to provide coverage for the performance of a bone mass measurement study, an advance beneficiary notice (waiver statement) should be processed and the patient should be informed about the potential responsibility for payment before the test is done. CONCLUSION: Osteoporosis is an important and costly disorder that is rapidly increasing in prevalence in our society. Clinical endocrinologists have a critical role in the management of patients with this condition and an opportunity to contribute to high-quality care. Proper selection of patients for assessment and treatment and an understanding of certain restrictions and necessary documentation for insurance coverage may help obtain reimbursement for their care.

Bone Density↗