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Biomedical subjects

R L Byyny

Publications and source records attributed to R L Byyny.

At least 37 records · Page 2Linked to original sources
PubMed1988

Propranolol increases prostacyclin synthesis in patients with essential hypertension.

We tested the hypothesis that vascular prostacyclin synthesis is increased by propranolol and could account for some of the drug's antihypertensive effect. We studied 10 white patients with mild essential hypertension in a randomized, double-blind design to assess the effects of indomethacin with or without the addition of propranolol on blood pressure and vascular prostacyclin biosynthesis, as assessed by the urinary excretion of the major enzymatically produced metabolite of prostacyclin, 2,3-dinor-6-keto-prostaglandin F1 alpha (PGF1 alpha), F1 alpha (PGF1 alpha), measured by gas chromatography-mass spectrometry. Seven patients responded to propranolol with a lowering of mean arterial blood pressure in both supine and upright postures. The fall in mean arterial blood pressure (-14.1 +/- 2.1 mm Hg sitting; -17.4 +/- 1.7 mm Hg supine) with propranolol alone was significantly greater than that produced when propranolol was given to patients receiving indomethacin (-7.8 +/- 1.9 mm Hg sitting; -7.7 +/- 3.0 mm Hg supine). Our drug-responsive patients demonstrated a significantly lower excretion rate of 2,3-dinor-6-keto-PGF1 alpha than was found in an age and sex-matched group of normal volunteers. With propranolol treatment, drug-responsive patients showed a significant increase in the excretion of 2,3-dinor-6-keto-PGF1 alpha, such that the mean excretion was not significantly different from that in normal volunteers. Indomethacin caused a significant rise in mean arterial blood pressure and a significant fall in 2,3-dinor-6-keto-PGF1 alpha excretion, and it blocked the rise in urinary 2,3-dinor-6-keto-PGF1 alpha associated with propranolol therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Challenges in the education of the general internist.

The health care needs of most adults can best be met by a well-trained general internist. In the 1990s, general internists will find a surplus of specialists and subspecialists and an aging population. One of their major concerns will be controlling health care costs using a number of different strategies. Two of the major methods to control costs will be to place a greater emphasis on ambulatory care and to avoid hospitalization of patients whenever possible. To best prepare general internists, residency program directors will need to improve education in clinical practice by including more teaching in continuity of care in ambulatory settings, improved teaching of new content for practice, and increasing the number of program graduates entering practice as general internists.

Ambulatory Care↗
PubMed1987

Effect of a sustained-release formulation of trimazosin in mild to moderate hypertension.

A single-blind study was conducted to evaluate the blood pressure (BP) reduction and side effects of a sustained-release (SR) formulation of trimazosin in patients with mild to moderate hypertension. Eighteen individuals (age, 21-65 yr; mean diastolic BP, greater than 95 mm Hg) with essential hypertension were enrolled into the study. Each patient's dose was titrated to a range of 150-900 mg/d, with polythiazide added as necessary to achieve BP control. Four hours following the maximum titrated dose of trimazosin, mean standing and supine diastolic BPs were significantly lower than baseline readings. Supine systolic BP and supine and standing heart rate were not significantly lower than baseline. At 24 hours after administration of the maximum dose, there were no significant differences in heart rate of BP compared with baseline readings. Five of 16 patients responded to trimazosin therapy alone. Of the 11 treatment failures with trimazosin alone, five were therapeutic failures and six discontinued because of side effects. Only two of these 11 patients achieved satisfactory results with the combination therapy. Trimazosin SR acutely lowers BP three to six hours after administration. It appears to have a duration of action longer than six hours, but it is not sustained for 24 hours. The proportion of patients failing to respond in this sample was very high and suggests that for similar patients, the drug does not appear to be a very useful antihypertensive agent.

Adult↗
PubMed1987

Changing patterns of disease on an inpatient medical service: 1961-1962 to 1981-1982.

To assess changes in disease on an internal medicine teaching service, the records of 292 patients admitted to University Hospital, Denver, Colorado, in the academic years 1961-1962 or 1981-1982 were reviewed. It was hypothesized that patients admitted more recently would be older, more chronically and catastrophically ill, and more likely to have multiple illnesses than patients of an earlier era. Over time, length of stay and mortality rates decreased and acuteness of illness increased, whereas age, chronicity, and co-morbidity remained constant. Changes in the prevalence of some common diseases reflected evolving medical and social influences on hospital use. Modern medical residents are exposed to more patients for a shorter time. They see more acute illness but less of the ongoing process of diagnosis and treatment. Awareness of such changes can help educators design residency programs that better prepare internists for practice.

Acute Disease↗
PubMed1987

A double-blind, randomized, controlled trial comparing pinacidil to hydralazine in essential hypertension.

Pinacidil is a direct vasodilator with good absorption, a half-life of 2 to 4 hours, and side effects similar to those of other vasodilators. We hypothesized that controlled-release pinacidil would be comparable to or better than hydralazine for blood pressure control and side effects. A double-blind, randomized trial comparing pinacidil with hydralazine when combined with hydrochlorothiazide or propranolol to control side effects or the diastolic blood pressure was performed. Pinacidil decreased systolic and diastolic blood pressure from 156/100 mm Hg to 132/81 mm Hg. The increase in heart rate and weight with both drugs was controlled with the additional drugs. There was 1/17 successes on monotherapy with both drugs. When combined with other drugs there were 15/18 successes with hydralazine and 16/20 successes with pinacidil. Side effects were typical of vasodilators. Both drugs acutely increased plasma norepinephrine and epinephrine during chronic therapy.

Adult↗
PubMed1987

New thinking on hypertension in the elderly.

Most patients over the age of 60 with sitting casual systolic blood pressure averaging greater than 160 mm Hg and diastolic pressure greater than 90 mm Hg and those with isolated systolic hypertension with elevated mean arterial pressure should be treated to reduce their blood pressure to less than 160/90 mm Hg or the mean arterial pressure below 110 mm Hg without producing adverse effects. The treatment should be individualized when other patient characteristics indicate a preferred drug. When this is not the case, then a thiazide diuretic combined with a potassium-sparing diuretic, with the addition of a centrally acting alpha-agonist when needed to control blood pressure has been demonstrated to be effective. If the patient does not tolerate this, or if his blood pressure reduction is not satisfactory, then other drugs can be used effectively.

Aged↗
PubMed1986

Hypertension in the elderly.

Current data indicate that most patients over age 60 with systolic blood pressure greater than 160 mm Hg and diastolic blood pressure greater than 90 mm Hg should be treated. The current data support the use of a thiazide and potassium-sparing diuretic with the addition of a centrally acting antiadrenergic drug as needed to reduce the blood pressure to less than 160/90 mm Hg. This will reduce the morbidity and mortality, especially cerebrovascular events, severe congestive heart failure, development of severe or accelerated hypertension, nonfatal myocardial infarction, and sudden death. Those unable to take these medications or who do not have satisfactory reduction in blood pressure should have other antihypertensive drugs added or substituted to lower blood pressure to less than 160/90 mm Hg.

Aged↗
PubMed1986

Acute effects of increasing doses of urapidil in patients with hypertension.

In a randomized, double-blind, dose-ranging trial, the acute antihypertensive effects of 7.5, 15, 30, 45, 60, 90, and 120 mg single daily doses of urapidil were compared with those of placebo in 10 patients with essential hypertension. Patients were randomized to either urapidil or placebo, such that each active drug day was followed by a placebo washout day. Blood pressure and heart rate responses were measured in the supine position, immediately upon standing, and after 3 to 5 minutes of standing for each dose. A variable but significant reduction in systolic and diastolic blood pressures that lasted from 4.5 to 8 hours was observed primarily at the 60, 90, and 120 mg doses (P less than 0.05). The maximum reduction in diastolic blood pressure occurred in the standing position at 3 to 5 hours after dosing. When urapidil was compared with placebo, a change from the supine to the standing positions produced a significantly larger reduction in systolic and diastolic blood pressures (P less than 0.05) but no significant change in heart rate. This suggests an acute blood pressure lowering effect of urapidil that occurs predominantly in the standing position and that does not significantly increase heart rate.

Adult↗
PubMed1984

Selective and nonselective beta-blockade of the peripheral circulation.

The effects of selective beta 1- as compared to nonselective beta-adrenergic blocking drugs on the peripheral circulation have not been adequately investigated. Ten healthy subjects received placebo for 1 wk followed by 4 wk of either propranolol or metoprolol in equivalent but increasing doses each week. Subjects then crossed over to the other sequence of placebo and drug. Measurements of calf blood flow, mean blood pressure, and calculation of calf vascular resistance were obtained at rest, after three loads of supine exercise on a bicycle ergometer, and during isoproterenol infusion testing. At the doses chosen, both beta-adrenergic blocking drugs induced equivalent decreases in exercise heart rate. Metoprolol lowered resting and exercise mean blood pressure at most doses, whereas propranolol had less of an effect on this variable. Neither drug altered resting or exercise calf blood flow or vascular resistance. More isoproterenol was required to increase the heart rate and decrease the vascular resistance during treatment with propranolol than with metoprolol. We conclude that in normotensive subjects metoprolol is somewhat more effective than propranolol in lowering mean arterial pressure during exercise when the drugs are given at doses equivalent in effects on exercise heart rate. Neither drug has a deleterious effect on calf blood flow or vascular resistance. Despite this, a marked separation between the vascular beta 2-adrenergic-blocking effects of these drugs can be demonstrated with an isoproterenol infusion indicating beta 2-adrenergic-receptor sparing by metoprolol.

Adult↗
PubMed1982

Single-dose amoxicillin therapy with follow-up urine culture. Effective initial management for acute uncomplicated urinary tract infections.

To learn whether a single dose of amoxicillin is safe, effective therapy for acute uncomplicated urinary tract infections, 388 symptomatic nonpregnant women were randomly grouped to receive oral amoxicillin, either as a single 3 g dose of 250 mg three times a day for two weeks. Patients had quantitative as well as dip-slide cultures of urine and tests for antibody-coated bacteria in urine. Follow-up urine cultures were obtained one week after completion of treatment. Results of antimicrobial susceptibility and antibody-coated bacterial tests did not alter the randomized therapy. Among 162 patients with bacteriologically confirmed infections, cure rates were 60.6 percent (43 of 71) for single-dose versus 73.6 percent (67 of 91) for two-week treatment (p = 0.07). Although more antibody-coated bacteria-negative patients (89.6 percent; 26 of 29) were cured overall, a substantial proportion of antibody-coated bacteria-positive patients were also cured by both single-dose (59.3 percent; 32 of 54) and 14-day therapy (64.6 percent; 42 of 65). There were fewer adverse effects in the single-dose treatment group. We conclude that a single 3 g dose of amoxicillin, with follow-up urine culture, provides safe and effective management for acute uncomplicated urinary tract infections in nonpregnant women.

Adolescent↗
PubMed1980

Preventing adrenal insufficiency during surgery.

Primary adrenal insufficiency is characterized by cortisol and aldosterone deficiency; in the secondary form, cortisol alone is decreased. The symptoms are usually nonspecific and include hypotension, weight loss, and fatigue; volume depletion, hyperkalemia, and hyperpigmentation may be present in the primary form but are uncommon in the secondary form. The most common cause of secondary adrenal insufficiency is steroid therapy, which produces adrenal suppression in relation to the dose and duration of use. Sudden withdrawal may precipitate adrenal crisis; therapy must be continued until adrenocortical function recovers. Because cortisol deficiency increases vulnerability to stress, patients with known or suspected adrenal insufficiency require glucocorticoid prophylaxis before any surgical procedure, major or minor. Hydrocortisone, not cortisone acetate, should be used.

Adrenal Insufficiency↗
PubMed1980

Management of diabetics during surgery.

Proper management of diabetic surgical patients includes careful preoperative assessment, administration of adequate amounts of insulin and glucose during and after surgery, and frequent postoperative blood glucose determinations. With good control of blood glucose levels, many of the problems associated with surgery in diabetics can be prevented or improved.

Diabetes Complications↗
PubMed1979

New concepts of chronic pain and their implications.

When chronic pain fails to respond to therapy, the approach often have been based on outmoded concepts of the nature of pain. The current unified pain theory takes into account recent biochemical advances and can serve as a basis for more effective diagnostic and therapeutic approaches. Various treatment modalities are reviewed in the context of the psychology as well as the physiology of severe intractable pain.

Analgesics↗
PubMed1978

Perioperative diabetic consultation: a plead for improved training.

To determine the clinical and educational impact of an academic general internal medicine consultation service, the investigators selected as a model the perioperative management of diabetes mellitus. They analyzed 17 consultative episodes over two years by retrospective medical record review to identify patterns and shortcomings. Most patients were elderly black females with maturity-onset diabetes mellitus exhibiting numerous past diabetic complications and other active general medical problems. Major findings included common failure to define the consultation purpose or document adequately follow-up visits, incomplete professional adherence to published guidelines for perioperative diabetic management, and correlation between failure to document the consultant's own physical examination and failure to reach new conclusions. Median cost for consultant-recommended tests was $179 (range $82 to $552) without clear linkage between medical care process and outcome. Consultative skills must be taught more effectively if medical consultations are to have maximal impact.

Adult↗