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Biomedical subjects

P Chang

Publications and source records attributed to P Chang.

At least 325 records · Page 18Linked to original sources
PubMed1972

Angiotensin II vascular receptors: their avidity in relationship to sodium balance, the autonomic nervous system, and hypertension.

During intravenous administration of varying doses of angiotensin II antibody to anesthetized rats, apparently specific vascular receptors were characterized. These receptors compete with administered antibody to bind circulating angiotensin. This competitive phenomenon was used to evaluate the affinity of these receptors for angiotensin. Apparent vascular receptor affinity was defined by the amount of antibody required to block the blood pressure response to exogenous angiotensin. It was found that this receptor affinity varies directly with sodium intake so that the amount of antibody required to block was eightfold greater in normal animals on a high sodium intake, as compared with those on a low sodium intake. Sodium dependence of receptors was also demonstrated in nephrectomized animals, in desoxycorticosterone (DOC)-treated rats, and in chronic renal hypertension. Thus the observed changes in receptor affinity were usually inversely related to measured endogenous angiotensin II levels. Ganglionic blockade increased antibody requirement eightfold. All of these changes were consistent, with no overlap observed in response of individual animals from different groups. These results may explain the variation in pressor activity of angiotensin associated with changes in salt balance and ganglionic blockade. In general, when sufficient antibody was injected to block the effect of exogenous angiotensin a blood pressure lowering effect was also observed. Two exceptions were the nephrectomized and the one-kidney renal hypertensive animals, in both of which antibody administration had no effect on blood pressure. Additional results suggest that changes in receptor affinity are involved in the pathogenesis of various types of experimental hypertensions because the amount of antibody required to block angiotensin was enhanced in renal (twofold), DOC (fourfold), and genetic (fourfold) hypertension. Accordingly, changes in the affinity of these receptors could be critically involved in normal blood pressure control and in various forms of experimental and clinical hypertension, even when circulating angiotensin II levels are normal.

Angiotensin II↗
PubMed1971

Temperature dependence of catecholamine depletion by reserpine in the heart of the toad (Bufo marinus).

1. The catecholamines in toad ventricle were adrenaline (90%) and noradrenaline (10%); there was no dopamine.2. Phenoxybenzamine and tyramine stimulated the isolated heart and reduced the catecholamine content.3. Reserpine treatment of toads kept at 20 degrees C did not affect the adrenaline but reduced the noradrenaline content of the ventricle.4. At 37 degrees C, reserpine caused depletion of both adrenaline and noradrenaline, and the stimulant actions of phenoxybenzamine and tyramine were lost.

Adrenergic Agents↗
PubMedDate not supplied

Noninvasive mechanical body contouring: (Endermologie) a one-year clinical outcome study update.

LPG Endermologie is a machine-assisted massage system that allows positive pressure rolling, in conjunction with applied negative pressure to the skin and subcutaneous tissues (LPG Endermologie U.S. A. (800-222-3911). Endermologie was originally developed in the late 1970s in France to soften scars and standardize physical therapy; however, patients treated with the LPG machine also showed improvement in body contour and skin texture. Since then, Endermologie machines have been used in France, the United States, and many other nations as an alternative method to altering fat distribution in the subcutaneous plane. The authors have continued their study of determining the safety and efficacy of this machine. Since our last report in March 1997 (Ersek RA et al., Aesth. Plast. Surg. 21(2):61-67, 1997), we have compiled records of 85 additional patients. With this larger patient pool, we can expect more statistically accurate results. This study is composed of 85 women between the ages of 21 to 61. The study group exhibited a wide range of body habitus, initial weights, and final results. Out of 85 patients, 46 patients completed seven sessions of treatment and showed a mean index reduction in body circumference of 1.34 cm, while 39 patients who completed 14 sessions of treatments showed a mean index reduction in body circumference of 1.83 cm. A decrease in mean body circumference index was seen regardless of loss or gain in patients' weight in most cases.

Adipose Tissue↗
PubMedDate not supplied

Acupuncture for the treatment of cocaine addiction. Investigation of a needle puncture control.

We conducted a 6-week, single-blind study of acupuncture for cocaine dependence in methadone-maintained patients (N = 40) for the purpose of identifying an appropriate needle puncture control for use in future large-scale clinical trials. Patients were randomly assigned to receive daily acupuncture in three auricular sites plus one body site (LI-4), or in control sites within 2-3 mm of the four active sites. Overall, there was a positive response to treatment on a variety of drug-related and psychosocial measures. Cocaine use decreased significantly for patients in both needle puncture groups. The only statistically significant difference between the two types of needle puncture was on ratings of craving. Subjects rated each type of needle puncture as equally credible and perceived no significant differences on the acute effects of the two types of needle insertions. Power calculations based on these findings suggest that very large sample sizes would be required to detect treatment differences between this control condition and active acupuncture. Alternative controls are suggested, and the challenges inherent in implementing controlled clinical trials of acupuncture are discussed.

Acupuncture Points↗
PubMedDate not supplied

Antitumor agents, 75. Synthesis of cytotoxic anthraquinones digiferruginol and morindaparvin-B.

A simple and efficient synthesis of digiferruginol (4) and morindaparvin-B (10) is described. Marschalk reaction of 1-hydroxyanthraquinone afforded 1-hydroxy-2-methylanthraquinone (2). Treatment of 2 with N-bromosuccinimide and benzoyl peroxide led to 1-hydroxy-2-bromomethylanthraquinone (3), which was converted to 4 with AgNO3 in quantitative yield. Methylation of 1,5-dihydroxyanthraquinone yielded a dimethyl ether (6), which was partially demethylated with boron trifluoride to a difluoroboron chelate (7). Treatment of 7 with alkaline HCHO and sodium dithionate gave rise to 1-hydroxy-2-hydroxy-methyl-5-methoxyanthraquinone (9). Cleavage of the 5-methyl ether of 9 with boron tribromide furnished 10.

Anthraquinones↗
PubMedDate not supplied

Onychomycosis in children: prevalence and management.

Onychomycosis in children is often accompanied by tinea pedis and a family history of onychomycosis. The prevalence of onychomycosis in children is substantially lower than that of adults; therefore it is important to confirm the clinical diagnosis. The most common presentation of onychomycosis is the distal and lateral subungual type. The organism most commonly isolated in North America is Trichophyton rubrum. Oral antifungal therapy is required, especially when the onychomycosis is of moderate to severe intensity, with nail matrix involvement. The new oral antifungal agents itraconazole, terbinafine, and fluconazole are being increasingly used for the treatment of onychomycosis. Review of the literature suggests that these agents are effective and safe in managing onychomycosis in children. The short duration of therapy required with these drugs should help improve compliance. The data suggest that the new oral antifungal agents have a role in the treatment of onychomycosis in children. Further experience will help us better position these drugs when evaluating the management of onychomycosis in children.

Administration, Oral↗