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Biomedical subjects

J C Yang

Publications and source records attributed to J C Yang.

At least 217 records · Page 12Linked to original sources
PubMed1985

Plasma fibronectin response to Escherichia coli and hemoglobin.

Low levels of plasma fibronectin (PFN), an adhesive glycoprotein postulated to augment reticuloendothelial function, can predispose animals to a poor clinical outcome following sepsis. In the present study, the PFN levels of adult male rats were measured prior to injection of intraperitoneal Escherichia coli and/or stroma-free hemoglobin (SFH) and subsequently at 4, 24, and 48 hours. Intraperitoneal E coli alone elicited insignificant PFN level depression at four hours, with significantly elevated levels only in the high-dose group at 24 (P less than .05) and 48 hours (P less than .01). Intraperitoneal SFH alone did not alter PFN levels from baseline values; when combined with E coli significant four-hour level depression is noted (P less than .05). Elevation of PFN levels by 24 hours occurs in a dose-dependent fashion, returning to baseline values 48 hours postinoculation. Significant mortality was observed only with high doses of E coli combined with SFH. The PFN levels are elevated 24 to 48 hours following high-dose E coli injection. Stroma-free hemoglobin alone has no effect, but when combined with E coli results in PFN level depression four hours postinoculation, contributing to impairment of systemic host defenses and possibly predisposing to greater mortality.

Animals↗
PubMed1984

Plasma fibronectin response to sepsis: mobilization or synthesis?

Plasma fibronectin (PFN) is a high molecular weight adhesive glycoprotein. Following trauma or sepsis PFN is acutely depleted, with rapid restoration of normal or supranormal levels after 24 to 48 hours. Cecal ligation with perforation provides an animal model of surgical trauma combined with polymicrobial sepsis. The present study examines whether this PFN level restoration 6 to 24 hours postoperatively is associated with de novo PFN synthesis and how this response is altered by pre-existing protein-calorie deprivation. Thirty-six adult male rats were divided into four groups: I--Controls, II--Prefasted Controls, III--Ligated, IV--Prefasted and Ligated. Control and experimental groups received intracardiac 35S-methionine 2 hours postoperatively. Plasma fibronectin (PFN) levels, PFN specific activity, plasma total protein, and total protein specific activity were determined at 0, 6, 24, and 48 hours postoperatively. Ligated rats (Groups III & IV) demonstrated significant PFN level increases 24 to 48 hours postoperatively (p less than 0.01-0.05). Despite a significant preoperative PFN level depression in prefasted rats (Groups II & IV), the 24-48 hours response to cecal ligation was not significantly altered. PFN specific activity was significantly increased among the operative groups 6 hours postoperatively, demonstrating de novo PFN synthesis following cecal ligation and perforation.

Animals↗
PubMed1984

Modulators of plasma fibronectin response during sepsis.

Plasma fibronectin (PFN) depletion has been associated with poor outcome in patients with sepsis or those who have experienced trauma; restoration of normal levels appears beneficial. PFN synthesis is increased after cecal ligation even in malnourished animals with sepsis, implying that stimulation of endogenous PFN synthesis is possible. One hundred rats received either a single therapeutic agent (gelatin, heparin, indomethacin, urokinase, captopril, or endotoxin) or the combination of a cecal ligation and a single agent (cimetidine, methylprednisolone, epsilon-aminocaproic acid (EACA), or transaminomethyl cyclohexane carboxylic acid. PFN levels were measured by enzyme-linked immunosorbent assay at 0, 24, and 48 hours. Only endotoxin alone caused significant PFN elevation at 24 to 48 hours (p less than 0.01); however, its multiplicity of effects precludes localization of regulatory pathways. Methylprednisolone results in an accelerated rise in PFN levels after operation (p less than 0.05), probably through an intracellular augmentation PFN synthesis. EACA attenuates the postoperative response while transaminomethyl cyclohexane carboxylic acid augments the PFN rise. This effect of EACA implies the existence of a proteolytic fragment capable of stimulating PFN synthesis. If a nontoxic factor can be identified, the use of exogenous PFN may be avoided.

Aminocaproic Acid↗
PubMed1983

Improvement of reliability of an oral examination by a structured evaluation instrument.

The main purposes of this study were to estimate the reliability of oral examinations administered to medical students during a clinical clerkship and to improve the reliability of this evaluation technique. In the first part of the study, the reliability of oral examinations as traditionally administered was estimated. The average intraclass reliability coefficient for these examinations was .48. Cassette recordings of these oral examinations were also rated by the faculty members. The average intraclass reliability coefficient of the ratings of the taped performances was .82. In the second part of the study, the reliability of oral examinations was investigated with the raters using a newly developed evaluation form. The average intraclass reliability of the oral examination using the evaluation form was .67, a noticeable increase over the .48 obtained without the form. The average intraclass reliability of ratings made from tape recordings of these oral examinations was .62.

Clinical Clerkship↗
PubMed1982

Treatment of hirsutism with spironolactone.

Clinical and endocrine evaluations of 39 patients with hirsutism were performed to determine the effectiveness and site(s) of action of an antiandrogenic compound, spironolactone. Treatment with spironolactone at a dose of 200 mg/day resulted in a clear beneficial effect on the quantity and quality of facial hair growth in 19 of 20 patients with moderate to severe hirsutism. Regression of hirsutism in terms of diameter, density, and the rate of facial hair growth was noticeable within two months. The maximal effect was observed at six months and was maintained at 12 months of treatment. Spironolactone was equally effective in reducing hirsutism in women with polycystic ovary syndrome and idiopathic hirsutism. These clinical observations were associated with a prompt and sustained reduction in levels of androgen of ovarian origin without affecting levels of adrenal androgen and cortisol. Apart from diuresis, which was limited to the first few days of treatment, there were no discernible side effects the one year of this study. Our results indicate that spironolactone is a highly effective and safe agent for the treatment of hirsutism through its inhibitory action on both ovarian androgen secretion and peripheral androgen action.

Amenorrhea↗
PubMed1982

Effect of intranasal cocaine on experimental pain in man.

Sixteen healthy male volunteers had 30 mg of cocaine HCI solution or normal saline placebo impregnated in cotton-covered applicators administered intranasally on different days in a double-blind procedure. Ischemic tourniquet pain was significantly less after cocaine than it was in pretreatment control. It was also significantly less than after administration of a placebo. Responses to questionnaires concerning subjective drug effects, mood, and alertness revealed little change in psychological status associated with either cocaine or placebo. Thus, the reported decrease in pain was probably not caused by a change in affect or by altered consciousness. These results indicate that, in addition to its known properties as a local aesthetic, cocaine when applied intranasally exerts an analgesic effect.

Administration, Intranasal↗
PubMed1980

Choledochofiberoscopy in the postoperative management of intrahepatic stones.

We prefer a nonaggressive approach to the treatment of high risk patients with intrahepatic stones. We perform extensive choledochotomy, remove all accessible intrahepatic stones, use bouginage of all stenotic segments and maintain patency with a T-tube stent. Postoperatively, we extract the remaining intrahepatic stones mainly with the choledochofiberscope and various types of forceps. The combined use of the Burhenne catheter and Dormia basket and the different types of curved forceps, scoops and Bakes' dilator has improved the success rate of removal. Thirty patients have thus far been treated in this manner with encouraging results.

Adolescent↗
PubMed1980

Antagonism of nitrous oxide analgesia by naloxone in man.

The possible reversal of nitrous oxide analgesia by naloxone was investigated. Two studies were conducted in 21 healthy male subjects, who responded to ischemic pain produced by tourniquet applied to the upper arm for 15 min, while breathing air or nitrous oxide, 33 per cent. Using a double-blind procedure, the subjects received intravenous injections of naloxone and saline solution on different days. In eight subjects, naloxone, 8 mg, administered without nitrous oxide, had no effect on pain report. However, unlike saline solution, naloxone, 8 mg, decreased significantly the analgesia induced by nitrous oxide. In 13 subjects, naloxone, 4 mg, also decreased significantly the effect of nitrous oxide analgesia in comparison with saline solution. Naloxone showed its reversal effect mainly on sensory response rating obtained during the painful stages of ischemia, between 11 and 15 min. The results suggest that analgesia induced by nitrous oxide may be partly related to the opiate receptor--endorphin system in man.

Analgesia↗
PubMed1976

Pharmacokinetics of naloxone in rats and in man: basis for its potency and short duration of action.

Using a specific and sensitive radioimmunoassay, naloxone concentrations in the brains and sera of rats were measured at intervals for four hours following iv injection (5 mg/kg). Decrement curves of naloxone were compared with those after iv injection of morphine (5 mg/kg). Serum concentration of naloxone at 5 minutes was 1.45 +/- 0.1 mug/ml (mean +/- SE) and that of morphine was 1.0 +/- 0.08 mug/ml. Their serum half-lives from one to four hours were approximately the same, 30-40 minutes. With naloxone, the brain-serum concentration ratios ranged from 2.7 to 4.6. Concentration of naloxone in the brain declined parallel to that in the serum. However, with morphine the initial brain concentration was approximately one tenth that in the serum (0.096 +/- 0.04 mug/ml). The brain morphine concentration was sustained for one hour, while serum morphine concentrations declined from 1.0 to 0.19 mug/ml during this period. Two minutes after iv injection of naloxone HCl (0.4 mg) in nine healthy volunteers, the serum drug concentration was 0.01 +/- .001 mug/ml. At 5 minutes, 97 per cent of the administered dose was no longer found in the serum, the serum concentration being 0.004 +/- .0003 mug/ml. From 20 minutes to two hours after injection, the calculated mean serum half-life of naloxone was 64 minutes. These results suggest that the rapid penetrance of naloxone into the brain and the high brain-serum concentration ratio contribute to its rapid onset of action and potency as a narcotic antagonist. The rapid decline of naloxone concentration in the brain found in the animal model, in contrast to that of morphine, could be the basis for its relatively short duration of action.

Adult↗