PubMed Health⌕ Search

Biomedical subjects

K K Hui

Publications and source records attributed to K K Hui.

50 records · Page 3Linked to original sources
PubMed1982

A study of beta-adrenergic and prostaglandin receptors in patients with aspirin-induced bronchospasm.

Nine patients with aspirin-induced bronchospasm were compared with age-matched normal controls to test the hypothesis that a defect in the beta-adrenergic system could lead to excessive dependence on prostaglandins to maintain bronchodilator function. Lymphocyte beta-receptor density and affinity were measured by 3H-dihydroalprenolol binding. Beta-receptor function was measured in terms of cyclic AMP accumulation in response to isoproterenol. Prostaglandin (PG) responsiveness was measured in terms of cyclic AMP accumulation caused by PGE1 stimulation. No difference was found in either ther number of beta-adrenergic receptors (1234 +115 vs 1213 +82) or dissociation constant (1.40 +0.23 nM vs 1.19 +0.07nM) (mean +SEM) between the asthmatic and the control group, respectively. Furthermore, neither group showed any difference in maximally stimulated cyclic AMP in response to isoproterenol and PGE 1. Thus we find no evidence of an inherent defect of beta-adrenergic receptor and function to account for the susceptibility to aspirin-induced bronchospasm.

Adult↗
PubMed1982

Lymphocyte beta-adrenergic receptors are not altered in hyperthyroidism.

Binding of (-)3H]-dihydroalprenolol (3H-DHA) to lymphocytes from five thyrotoxic patients and five age- and sex-matched contents were examined to ascertain whether beta-adrenergic receptor number or binding affinity were altered in thyrotoxicosis. Whereas an increase in beta-adrenoceptor density has been reported in triiodothyronine-induced hyperthyroidism, we did not find changes in beta-adrenergic receptor density or binding affinity. In one patient studied sequentially, we did not find alteration in 3H-DHA bindings before or after the subject was rendered euthyroid. We conclude that lymphocyte beta-adrenergic receptor density and affinity are not altered in spontaneous hyperthyroidism.

Adult↗
PubMed1982

Reversal of human lymphocyte beta-adrenoceptor desensitization by glucocorticoids.

To investigate the effect of glucocorticoids on beta-agonist-induced desensitization, we studied the effect of a single intravenous dose of methylprednisolone (2 mg/kg) on beta-receptor density and affinity in lymphocytes from four normal and four mildly asthmatic subjects at the end of 3 to 5 wk of terbutaline therapy and from four normal subjects taking no other drug. Terbutaline decreased (-)[3H]-dihydroalprenolol binding sites by 53% in normal and by 42% in asthmatic subjects. Methylprednisolone restored the number of binding sites to levels statistically indistinguishable from the preterbutaline values in both groups of subjects. In subjects not exposed to terbutaline beforehand there was no significant alteration in receptor density after methylprednisolone, nor in normal lymphocytes incubated in vitro for 90 min with hydrocortisone (10(-5)M). No significant change in the dissociation constant was observed in any situation. A single intravenous dose of methylprednisolone reverses terbutaline-induced down-regulation of beta-adrenoceptors. This may provide a mechanism for the beneficial effect of steroids in restoring catecholamine responsiveness in asthmatic subjects.

Adult↗
PubMed1982

Subsensitization of beta-adrenoceptors in airways and lymphocytes of healthy and asthmatic subjects.

Subsensitization of beta-adrenoceptors in airways and lymphocytes developing during 4 to 5 wk of orally administered terbutaline (a long-acting beta 2 selective bronchodilator) was compared in 10 healthy subjects and 11 subjects with mild asthma. The following results were obtained. Normal subjects developed a significant reduction in acute bronchodilator responsiveness to inhaled isoproterenol but not to subcutaneously administered terbutaline. The subjects with asthma failed to develop any alteration in responsiveness to either inhaled isoproterenol or subcutaneously administered terbutaline. None of 5 normal or 4 asthmatic subjects studied demonstrated any significant change in sensitivity to histamine-induced bronchospasm or any significant decrease in the acute protective effect of subcutaneously administered terbutaline against histamine-induced bronchospasm. Marked and significant decreases occurred in the density of lymphocyte beta-receptor sites in both groups. Maximal isoproterenol-stimulated cyclic AMP responses in lymphocytes from normal subjects were reduced, but in asthmatics, in whom the baseline values were lower to begin with, a similar decrease was not observed. In most instances, the number of receptor sites returned to normal within 2 wk after cessation of terbutaline. A single dose of methylprednisolone caused a return to normal values within 16 h. We conclude that chronic therapy with an oral beta 2-adrenostimulant, although producing striking and significant down-regulation of beta-adrenergic receptors of peripheral lymphocytes, does not lead to physiologically detectable beta-adrenoceptor subsensitivity in the airways of asthmatics or to consistent subsensitivity in the airways of healthy persons.

Adolescent↗
PubMed1980

beta-Endorphin. Intravenous infusion causes behavioral change in psychiatric inpatients.

Ten depressed and eight schizophrenic patients received synthetic human beta-endorphin infusions in a double-blind, placebo-controlled, crossover design. Physicians' and nurses' ratings and patients' self-ratings were used to measure behavioral change. Depressed patients improved significantly two to four hours after beta-endorphin treatment when compared with placebo treatment. There was no significant change in the schizophrenic patients as a group, although six of eight worsened after beta-endorphin treatment. No significant behavioral effects were observed during the infusions themselves or on postinfusion days.

Adolescent↗
PubMed1980

Intravenous infusion of beta-endorphin increases serum prolactin, but not growth hormone or cortisol, in depressed subjects and withdrawing methadone addicts.

In a randomized, double blind, cross-over study, human beta-endorphin or saline was infused iv over 30 min into six depressed psychiatric patients and four methadone addicts. All depressed subjects showed prompt, 2- to 4-fold increases in serum PRL levels, which lasted at least 2 h. The addicts, who were undergoing acute methadone withdrawal, showed similar PRL increases, which were dose dependent. beta-Endorphin did not increase serum levels of cortisol or GH in either group of subjects. These results suggest that iv beta-endorphin has potent but selective neuroendocrine effects in depressed patients and subjects withdrawing from methadone.

Adult↗
PubMedDate not supplied

Blood pressure response to the "second cup of coffee".

Twenty young male coffee-drinkers consumed 150 mg of caffeine in decaffeinated coffee three times a day for 8 days. On days 3, 4, 7, and 8, caffeine or a placebo was administered in the laboratory at 11 A.M., 8 A.M., 11 A.M., and 8 A.M., respectively, in a randomized double-blind crossover design. There was a blood pressure increase relative to the placebo 45 min after taking caffeine at 8 A.M. (5.8/6.5 mm Hg). An increase of 2.4/5.2 mm Hg was seen with the second cup of coffee at 11 A.M. The lower the subject's pre-coffee serum caffeine level, the higher the systolic response, both at 8 A.M. (r = -0.60) and at 11 A.M. (r = -0.62). Because of the pressor effect resulting from habitual caffeine intake, the adverse implications of caffeine use should be considered.

Adolescent↗
PubMedDate not supplied

Hostility and differences between clinic, self-determined, and ambulatory blood pressure.

This study examined the role of personality factors in differences between three methods of assessing blood pressure (clinic, self, ambulatory) in 45 patients with mild hypertension. The data were obtained after the patients were withdrawn from antihypertensive medications and had achieved stable clinic diastolic blood pressure levels of 95 to 110 mm Hg, averaged over three visits in 2 to 4 weeks. Significant differences were obtained in systolic blood pressure (SBP) and diastolic blood pressure (DBP) as a function of method of assessment. These differences in both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were associated with individual differences in the total score and several subscales of the Buss-Durkee Hostility Inventory (Assault, Resentment, Guilt), but not in anxiety, depression, or other characteristics. High hostile subjects had consistently high blood pressure values in both clinic, self, and ambulatory recordings. Low hostile subjects were significantly lower in self-recorded blood pressure readings taken at home and in ambulatory recordings, compared with clinic values. Implications of these findings for "white coat hypertension" are discussed.

Adult↗