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Biomedical subjects

T G Hall

Publications and source records attributed to T G Hall.

7 recordsLinked to original sources
PubMed1993

Update on the medical treatment of hypercalcemia of malignancy.

Recent information on the pathophysiology and treatment of hypercalcemia of malignancy is reviewed, and the roles of two new agents, gallium nitrate and pamidronate, are discussed. Current evidence suggests that parathyroid hormone-related protein is the most important mediator of humoral hypercalcemia of malignancy. In patients with local osteolytic hypercalcemia, cytokines have been implicated as mediators. Effective treatment of hypercalcemia of malignancy may improve patients' quality of life, although an episode of hypercalcemia is a poor prognostic indicator for survival. Gallium nitrate is more effective than salmon calcitonin and possibly more effective than etidronate in the treatment of hypercalcemia of malignancy. The primary adverse effect of gallium nitrate is nephrotoxicity, and its use must be avoided in patients who have renal dysfunction or who are receiving nephrotoxic drugs. Pamidronate is more effective than etidronate in the treatment of hypercalcemia of malignancy and can be administered as a single i.v. dose. The adverse effects of pamidronate include mild fever, hypocalcemia, and hypophosphatemia. Compared with gallium nitrate, pamidronate offers a more convenient dosing regimen, is less frequently associated with nephrotoxicity, and is less expensive. Single i.v. doses of either pamidronate or plicamycin effectively lower serum calcium levels and are reasonable choices for maintenance therapy. Gallium nitrate and pamidronate may be slightly more effective than previously available agents for initial treatment of hypercalcemia. Pamidronate currently offers the best combination of effectiveness, ease of administration, and a low rate of adverse effects.

Animals↗
PubMed1989

The efficacy of inhaled beclomethasone in chronic obstructive airway disease.

The objective of this study was to examine the effectiveness of inhaled beclomethasone in the treatment of stable chronic obstructive airway disease (COAD). Eight patients completed a randomized, double-blind, placebo-controlled, crossover trial of inhaled beclomethasone and oral prednisone. Each patient received 3 treatment regimens given for 14 days: inhaled beclomethasone, prednisone, and placebo. There were no statistically significant differences in pulmonary function tests, oxygen cost diagram, or 12-minute walking distance test among the regimens. The only improvement in arterial blood gasses was partial pressure of oxygen, which was negligibly increased during prednisone treatment compared with beclomethasone and with placebo (p less than 0.05). Evaluation of 95% confidence intervals indicated that clinically significant mean differences were unlikely with either beclomethasone or prednisone. Larger studies are required to determine if a responsive subgroup exists, and to determine if this form of therapy has a role in treatment of COAD.

Administration, Inhalation↗
PubMed1989

Medical treatment of hypercalcemia.

Calcium homeostasis and the symptoms, etiology, and general medical management of hypercalcemia are reviewed. Hypercalcemia, an elevation in total serum calcium concentration, may produce neurologic, gastrointestinal, renal, and cardiovascular disturbances; it may also cause calcification in extraskeletal tissue. Hyperparathyroidism and malignancy cause more than 90% of cases of this potentially fatal disorder. When correction of the underlying cause of hypercalcemia is impossible, calcium-lowering therapy is necessary. Acute management of hypercalcemia often involves rehydration, mobilization of the patient, and furosemide-induced diuresis. These measures may be followed by intravenous administration of etidronate, plicamycin, or calcitonin. Agents used in the long-term management of hypercalcemia include oral phosphates, oral etidronate, intermittent intravenous plicamycin, and, in selected patients, corticosteroids and nonsteroidal anti-inflammatory agents. Investigational calcium-lowering agents include gallium nitrate, ethiofos, dichloromethylene diphosphonate, and aminohydroxyproline diphosphonate. Many agents are available for the treatment of hypercalcemia. Therapy can be individualized by integrating knowledge of the physiologic causes of hypercalcemia, the mechanism of action of calcium-lowering drugs, and the patient's other disease states. Further studies are needed to define the role of investigational calcium-lowering agents.

Adrenal Cortex Hormones↗
PubMed1987

Regulatory domains of erythrocyte ankyrin.

This report provides evidence for regulatory domains of erythrocyte ankyrin that modulate associations of this protein with the anion transporter and spectrin. Two domains have been identified that are located at opposite ends of the polypeptide chain. One domain (Mr = 20,000), which is released by calpain, is primarily involved in regulation of the association of ankyrin with the anion transporter. The Mr = 195,000 fragment remaining after calpain cleavage binds to ankyrin-depleted inside-out vesicles with a 8-fold reaction in affinity, although with a 2-fold increase in number of high affinity sites. Cleavage of ankyrin by calpain induces a reduction in the frictional ratio from 1.55 to 1.33 suggesting either that the calpain-sensitive domain is present as a tail extending from a globular domain, or that upon cleavage ankyrin undergoes a major change in conformation. The other proposed regulatory domain is missing in protein 2.2, a form of ankyrin present in human erythrocytes that has a molecular weight about 29,000 smaller than ankyrin. Protein 2.2 is distinct from the calpain fragment based on peptide maps and reaction with domain-specific antibodies. The activity of the domain deleted from protein 2.2 has been inferred by comparison of ankyrin and protein 2.2, with the assumption that differences between these proteins are due to the missing domain. Protein 2.2 is an activated form of ankyrin that has a 3-fold higher affinity for spectrin and binds to twice the number of high affinity anion transporter sites. These observations suggested that removal of terminal domains of ankyrin may have a physiological role in modulation of ankyrin activity.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1983

A comparison of pharmacists and physicians on the quality of prescribing for ambulatory hypertensive patients.

This article discusses a quasi-experimental study of the quality of pharmacists' and physicians' drug prescribing for ambulatory hypertensive patients in a health maintenance organization. The null hypothesis was that there is no difference between pharmacists and physicians as to the quality of drug prescribing for hypertensive patients. Analysis revealed no difference in prescribing between the physician group and the pharmacist group on the scoring for the presence of drug interactions, appropriateness of quantities, dose, and patient directions. The pharmacist prescriber group did significantly better than the physician group, however, on choosing the appropriate drug, prescribing for a "positive effect on the patient's health," and overall appropriateness from combining all the above scales (p less than 0.05). The diastolic pressures of the patients assigned to the pharmacists' group were not significantly different from the physicians' group on pretest, but on posttest the diastolic pressures were slightly lower in the pharmacists' group (p less than 0.10).

California↗
PubMedDate not supplied

Effect of sucralfate on phenytoin bioavailability.

The mechanism of action of the antiulcer agent, sucralfate, involves drug binding to proteins, pepsin, and bile salts. The potential for sucralfate to bind to, and inhibit the oral absorption of, concurrently-administered drugs has been studied for very few agents. Phenytoin bioavailability was studied following a single dose of phenytoin 500 mg po in nine normal subjects during a control period and when given with sucralfate. Area under the serum concentration-time curve was compared at 48 hours (AUC48) and 120 hours (AUC120) using observed and extrapolated data. The phenytoin AUC48 was reduced from 173.6 +/- 22.6 mg . h/L to 157.1 +/- 19.6 mg . h/L (p less than 0.02), and the phenytoin AUC120 was reduced from 200.5 +/- 31.9 mg . h/L to 185.0 +/- 26.8 mg . h/L (p less than 0.05), when sucralfate was administered. Because AUC comparisons for drugs with nonlinear elimination kinetics may reflect changes in rate, as well as extent, of absorption, these small changes in AUC may not reflect a change in the fraction of dose absorbed. However, our results suggest that sucralfate does affect phenytoin absorption. Further studies may be useful in determining the precise nature and clinical importance of this interaction.

Adult↗