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Biomedical subjects

J Park

Publications and source records attributed to J Park.

At least 433 records · Page 24Linked to original sources
PubMed1983

Improved exercise myocardial perfusion during lidoflazine therapy.

Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise.

Adult↗
PubMed1982

Variability of spontaneous and exercise-induced ventricular arrhythmias in the absence and presence of treatment with acebutolol or quinidine.

A randomized double-blind crossover trial was undertaken in 20 volunteers to evaluate the effects of acebutolol and sustained release quinidine sulfate. The patients had an average of 10 or more premature ventricular complexes/hour on two 24 hour electrocardiographic recordings, or 10 or more/min during two cycle stress tests, or any number of complex forms of ventricular ectopic activity on either test. The 24 hour recordings yielded greater detection of complex forms than did stress tests and manifested similar relative variability in frequency of ventricular ectopic beats. The extent of variability from hour to hour within the 24 hour monitoring periods tended to have an increasing relation with frequency of ectopic beat activity regardless of the presence or absence of treatment. Within-patient variability among periods with equivalent treatment status also tended to have such an increasing relation with frequency of ectopic beat activity. About 35 percent of the variation was among subjects, 20 percent among months within subjects, 20 percent among days in months and 25 percent among hours in days. Acebutolol, 300 mg three times daily, produced effective beta receptor blockade and was better tolerated than sustained release quinidine sulfate in identical doses and had equal suppressant effects. The results of the variability studies provide guidelines for the design of adequate clinical trials testing suppressant interventions.

Acebutolol↗
PubMed1982

A comparison of methods for assessing thyroid function in nonthyroidal illness.

We studied various tests of thyroid function in sick patients with nonthyroidal illness (NTI) in order to determine the utility of each test for differentiating these patience from a group with hypothyroidism. We evaluated each test in 22 healthy volunteers who served as controls, 20 patients with hypothyroidism, 14 patients admitted to medical intensive care unit whose serum T4 was less than 5 micrograms/dl, 13 patients with chronic liver disease, 32 patients on chronic hemodialysis for renal failure, 13 ambulatory oncology patients receiving chemotherapy, 16 pregnant women, 7 women on estrogens, and 20 hyperthyroid patients. On all samples, we measured serum T4, the free T4 index by several methods, free T4 by equilibrium dialysis, free T4 calculated from thyronine-binding globulin (TBG) RIA, free T4 by three commercial kits (Gammacoat, Immophase, and Liquisol), T3, rT3, and TSH (by 3 different RIAs). Although all of the methods used for measuring free T4 (including free T4 index, free T4 by dialysis, free T4 assessed by TBG, and free T4 assessed by the 3 commercial kits) were excellent for the diagnosis of hypothyroidism, hyperthyroidism, and euthyroidism in the presence of high TBG, none of these methods showed that free T4 was consistently normal in patients with NTI; with each method, a number of NTI patients had subnormal values. In the NTI groups, free T4 measured by dialysis and the free T4 index generally correlated significantly with the commercial free T4 methods. Serum rT3 was elevated or normal in NTI patients and low in hypothyroid subjects. Serum TSH provided the most reliable differentiation between patients with primary hypothyroidism and those with NTI and low serum T4 levels.

Alpha-Globulins↗
PubMed1982

The effects of lidoflazine on exercise performance and thallium stress scintigraphy in patients with stable angina pectoris.

Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a 7-month study, 36 patients with stable angina pectoris were tested during a 3-month single-blind placebo phase. Nineteen were then randomized by double-blind methods to lidoflazine and 17 to placebo therapy. The lidoflazine group had a significant (p less than 0.01) reduction in anginal attacks; the placebo group did not. Exercise testing demonstrated that lidoflazine therapy was associated with a 34% increase in total work performance and a 15.6% increase in peak calculated oxygen uptake during double-blind treatment (both p less than 0.004 compared with the placebo group). Heart rate was significantly reduced at submaximal levels of exercise during lidoflazine therapy (p less than 0.04). Nitroglycerin consumption and electrocardiographic changes at the end of exercise did not change during the double-blind phase. In a second study of six similar patients, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise.

Angina Pectoris↗
PubMed1981

Comparison of nadolol, a new long-acting beta-receptor blocking agent, and placebo in the treatment of stable angina pectoris.

Nadolol, a new nonselective beta 1 and beta 2 adrenergic blocking agent, has a plasma half-life of 17 to 23 hours. We studied 37 volunteers with stable angina pectoris who had five or more episodes of pain per week and who also had a 1 mm or greater ST segment depression 80 msec past the J point during a Bruce protocol treadmill test. An eight-week placebo controlled run-in period preceded double-blind randomization to nadolol administered once per day (17 patients) or identical appearing placebo for four weeks (20 patients), after which an exercise test was done. Diaries for pain episodes and nitroglycerin consumption were kept. Exercise tests were performed 24 hours after the last nadolol or placebo dose. Episodes of pain per week were reduced 59.8 percent after nadolol and 28.2 percent after placebo (P less than .01). Nitroglycerin consumption after nadolol was reduced 66.8 percent while after placebo it was reduced 36.2 percent (P less than .05). Resting and peak heart rates and peak rate-pressure products showed typical reductions due to beta-blockade 24 hours after nadolol compared with stability of these during placebo, all P less than .001. Exercise time after nadolol increased 42.2 percent, which was more than the 14.5 percent increase after placebo (P less than .05). Exercise work after nadolol increased 64.7 percent, greater than the 22 percent increase after placebo (P less than .05). Mean ST segment depression at end of exercise was little changed before and after treatment in both groups, reflecting consistency of effort. Improvement in symptoms and work capacity associated with nadolol significantly exceeded the placebo group responses. Unlike other available agents of this class, a single daily dose of nadolol produced therapeutically effective 24-hour beta-blockade in patients with disabling angina pectoris.

Angina Pectoris↗
PubMed1979

Treatment of severe 2,4-D and mecoprop intoxication with alkaline diuresis.

1 Self-poisoning with a selective weedkiller containing 2,4-D and mecoprop in a 39 year old man resulted in prolonged deep coma, pyrexia, hyperventilation, hypoxaemia, myotonia, skeletal muscle damage and electrocardiographic changes consistent with cardiomyopathy. 2 The admission plasma concentrations of 2,4-D and mecoprop were 400 and 751 microgram/ml respectively. The patient remained gravely ill with no signs of improvement for 2 days with supportive therapy and there was no fall in the 2,4-D level. 3 Alkaline diuresis greatly increased the renal clearance of 2,4-D, and there was a rapid fall in plasma concentration (T1/2 3.7 h) with corresponding clinical improvement. The effect on the elimination of mecoprop was similar, but less dramatic. 4 Forced alkaline diuresis may improve the otherwise very poor prognosis in severe intoxication with 2,4-D and related weedkillers.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1978

Changing pattern of drugs used for self-poisoning.

In 1967-76 the annual number of admissions to a poisoning treatment centre rose from 964 to 2134. The proportion of admissions caused by taking barbiturate hypnotics and methaqualone fell considerably while that caused by taking benzodiazepines and tricyclic antidepressants increased. As a result the proportion of patients admitted unconscious fell from 23% to 15%. The declining contributions of barbiturates and methaqualone and increased importance of tricyclic antidepressants were significant in all grades of coma. The change in drugs taken, however, has not yet reduced the percentage of unconscious patients needing endotracheal intubation or assisted ventilation, and hypothermia remains as common. Only hypotension has become less frequent as antidepressants replace barbiturates as the main cause of drug-induced coma. The use of salicylates for self-poisoning is declining slowly, and paracetamol poisoning is now as common.

Acetaminophen↗
PubMed1978

Parent-offspring resemblance for specific cognitive abilities in Korea.

Regressions of offspring on midparent value for tests of specific cognitive abilities in Korea were considerably higher than those for Americans of Japanese ancestry or Americans of European ancestry tested in Hawaii. This greater parent-offspring resemblance in Korea may be due to the particular method of test administration or to an increased genetic variance resulting from assortative mating. The pattern of parent-child correlations for three relatively pure tests of spatial ability and for the spatial factor did not conform to that of a sex-linked recessive character.

Adolescent↗
PubMed1977

Treatment of paracetamol (acetaminophen) poisoning with N-acetylcysteine.

Fifteen patients with paracetamol (acetaminophen) poisoning were treated with intravenous N-acetylcystein (300 mg/kg given over 20 h). Mean admission and 4 h plasma-paracetamol concentrations were 262 and 369 microgram/ml, respectively. Liver-function tests remained normal or were only slightly disturbed in 11 of 12 patients treated within 10 h of paracetamol ingestion. Severe liver damage developed in the other patient and in the three in whom treatment was started more than 10 h after paracetamol ingestion. In contrast to cysteamine, N-acetylcysteine was very well tolerated and has the advantage of being available as a pharmaceutical preparation in a 20% sterile solution.

Acetaminophen↗
PubMed1977

Osmotic control of the release of prolactin and thyrotropin in euthyroid subjects and patients with pituitary tumors.

The effects of acute changes in serum osmolality on basal serum PRL and TSH levels and on responses of prolactin (PRL) and thyrotropin (TSH) to the thyrotropin-releasing hormone (TRH) analogue, N3im-methyl-TRH, were studied in ten euthyroid subjects and in three patients with PRL-secreting pituitary tumors. An oral water load of 20 ml/kg had no effect on basal serum PRL or TSH levels but did result in an increased PRL response to methyl-TRH in the ten euthyroid patients. Intravenous infusion of 5% sodium chloride in the ten euthyroid subjects significantly depressed basal serum PRL levels but had no effect on the PRL response to methyl-TRH. Infusion of hypertonic saline significantly decreased the TSH response to methyl-TRH. In the three patients with pituitary tumors, oral water loading and hypertonic saline infusion had no significant effect on the basal serum PRL and TSH or the PRL and TSH responses to methyl-TRH. The patients with pituitary tumors had a higher basal serum osmolality and a proportionately higher serum concentration of arginine vasopressin than the euthyroid patients. These data suggest that changes in osmolality in euthyroid patients may have a direct effect on the anterior pituitary's PRL and TSH response to a releasing factor.

Adult↗
PubMed1977

Ventilation and acid-base changes in deep coma due to barbiturate or tricyclic antidepressant poisoning.

Forty-two adults in deep coma due to uncomplicated overdosage with barbiturates or tricyclic antidepressants were studied to determine the effects of the drugs and the depth of coma on ventilation and acid-base balance. All the patients were breathing spontaneously. The usual acid-base disturbance was a mixed respiratory and metabolic acidosis. No differences in effects of barbiturates and tricyclic antidepressants could be demonstrated in either grade of coma studied. Patients who were completely unresponsive to painful stimuli were significantly more acidemic (arterial [H+] 51.4 nmole/liter c.f. 44.4 mole/liter) and hypoxic (PaO2 6.6 kPa c.f. 10.5 kPa) than those who showed a minimal response to pain. These findings could not be explained by differences in alveolar ventilation, and it is suggested that they are due to ventilation/perfusion imbalance.

Acid-Base Imbalance↗