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Biomedical subjects

L C Chu

Publications and source records attributed to L C Chu.

At least 19 recordsLinked to original sources

The clinical outcome of 137 rape victims in Hong Kong.

From 1 August 2001 to 31 July 2004, 137 patients were referred from the Association Concerning Sexual Violence Against Women to the Accident and Emergency Department at the Kwong Wah Hospital for alleged rape. Approximately half of the patients presented within 3 days of the alleged assault. Fifty-one patients were prescribed emergency contraception: one patient remained pregnant despite treatment and was referred with a further six patients to the Gynaecology Department for termination of pregnancy. Thirty-two patients received hepatitis B immunoglobulin injection. One patient had a positive result for rapid plasma reagin 3 months following the assault and was referred to the Social Hygiene Clinic. All tests for antibody to human immunodeficiency virus were negative. Antimicrobial therapy was prescribed for women who had an endocervical and/or high vaginal swab positive for Chlamydia trachomatis (n=9), Trichomonas vaginalis (n=1), and gonococcus (n=1).

Adolescent↗

Collagen in naturally occurring hypertrophied porcine myocardium.

A comparison of the collagen network in three dimensions was conducted in 8 hypertrophic cardiomyopathy (HCM)-affected and 8 normal hearts. All these hearts were obtained from male and age-matched pigs of the same breeding farm under identical feeding conditions. The selection of HCM-affected heart was based on the abnormal histologic features such as marked disorientation of muscle cells, thickening of the intramural coronary arterial wall with a narrowed lumen, endocardial fibrosis, and myocardial fibrosis. Mean values of heart weight and ratio of heart to body weight of HCM group were significantly (p < 0.01) increased by 36% and 47%, respectively, but not the body weight, as compared to those of the normal group. The scanning electron microscopic (SEM) investigation demonstrated that collagen weave, struts, and strands appeared more numerous in HCM-affected myocardium than in normals. Moreover, the tendons of collagen in HCM-affected myocardium showed increases in both numbers and thickness.

Animals↗

Acute relapsing hepatitis A in Taiwan--a rare event not related to multiple viral infection: a report of two cases.

From 1981 to 1993, 40 cases of acute type A viral hepatitis were reviewed and 2 cases (5%) of relapsing hepatitis were reported here. One case relapsed two weeks after remission and the other relapsed three weeks after remission, both had benign courses and recovered within four months. They were negative for serum hepatitis B surface antigen and hepatitis B core IgM antibodies. The serum autoantibodies, hepatitis C antibodies and hepatitis E antibodies were all negative during relapse. In summary, relapsing hepatitis A is rare in Taiwan and it is not related to multiple viral infections.

Acute Disease↗

Consensus at zero acquaintance: replication, behavioral cues, and stability.

That observers tend to agree in their ratings of a target even if they have never interacted with that target has been called consensus at zero acquaintance. The basic finding that consensus is highest for judgments concerning a target's degree of extraversion (EV) and somewhat weaker for judgments of conscientiousness is replicated. Several potential observable cues that might be used by judges when rating targets are examined. The finding that ratings of physical attractiveness correlate with judgments of EV is replicated. In Study 1, rapid body movements and smiling were also found to correlate with EV judgments. The level of consensus declined when initially unacquainted Ss interacted one-on-one (Study 2), but did not decline--and even increased--when Ss interacted in a group (Study 3). Ss judged as extraverted at zero acquaintance were also seen as extraverted after interacting with others.

Adult↗

Nitroglycerin concentration in plasma: comparison between transdermal therapeutic system and ointment.

This double-blind cross-over study evaluates in 12 male volunteers the time course of nitroglycerin concentration in plasma with use of the TTS-nitroglycerin, a controlled-release transdermal dosage form for nitroglycerin, and compares the bioavailability of nitroglycerin delivered from the transdermal system with that from three successive applications of 0.5 inch of 2% nitroglycerin ointment placed at 8 hr intervals over 10 cm2 of skin. The mean amounts of nitroglycerin available when subjects wore the TTS-nitroglycerin or received successive applications of ointment were 15.8 mg +/- 1.8 (SE) and 9.8 mg +/- 0.8, respectively. Mean plasma concentrations for both treatments ranged from 10-18 pg/ml-cm2. The normalized areas under the curves--353 and 410 pg/hr/ml-cm2, respectively--did not differ significantly. The ratio of clearance from the two dosage forms was 0.98 +/- 0.12. All subjects experienced mild-to-moderate side effects of nitrate therapy with both dosage forms and also decrease in blood pressure and increase in heart rate.

Administration, Topical↗

Plasma concentrations and haemodynamic effects of nitroglycerin during and after intravenous infusion in healthy volunteers.

The effects of nitroglycerin, infused intravenously at 3.4 and 7.5 micrograms/min over 30 min, on haemodynamic parameters were determined in the morning and the afternoon in a randomized, placebo-controlled study in 5 healthy volunteers. The mean steady-state concentrations of nitroglycerin reached in the plasma during the infusions of 3.4 and 7.5 micrograms/min were 0.35 +/- 0.06 ng/ml and 0.64 +/- 0.22 ng/ml, respectively. Wide inter-individual variation was noted. The nitroglycerin-induced increase in the orthostatic rise in heart rate and the change in digital-pulse-wave morphology roughly paralleled the plasma concentration, whereas the reduction in systolic blood pressure in the upright position was still evident 15 mins after the infusion, i.e. when nitroglycerin was no longer measurable in plasma. No significant diurnal variation in vascular sensitivity to the vasodilative action of nitroglycerin was demonstrable. The change in pulse-wave morphology resulting from the reduction in peripheral resistance (shift of the dicrotic wave in the descending limb towards the base-line) proved to be the most sensitive haemodynamic parameter.

Adult↗

Human pharmacological studies of a new transdermal system containing nitroglycerin.

A new transdermal therapeutic system (TTS) for the administration of nitroglycerin (NTG) was tested in human pharmacological studies in 26 healthy volunteers. Plasma concentrations and haemodynamic responses were determined after the application of the system in different dosages. The concentrations of NTG reached in the plasma were uniform and dose-related, i.e. dependent on the drug-release area, and showed only minor inter-individual variation. They remained almost constant as long as the system was in contact with the skin. Renewal of the system caused no appreciable change in the plasma concentration. The haemodynamic effects, like those of all nitrates, were not clearly related to the dose administered, and were not always dependent on the plasma concentration. Upon repeated application, NTG-TTS was well tolerated locally and systemically and led to no alteration in blood chemistry or haematological parameters. The typical nitrate headaches disappeared after a few days. The presence of the system on the skin caused no discomfort or inconvenience.

Administration, Topical↗

Time course and disposition of methazolamide in human plasma and red blood cells.

Methazolamide was determined in plasma, whole blood, and urine by a GLC-mass spectrometric method. Temporal patterns of methazolamide concentrations in plasma and red blood cells were obtained following single- and multiple-dose oral administration of the drug. The nonlinearity in the binding of the drug to the red blood cell carbonic anhydrase was evident from a comparison of plasma and red blood cells concentrations. The drug was cleared slowly from the red blood cells. The binding constants to the two isoenzymes of carbonic anhydrase were determined from the plasma and red blood cell concentrations and were in agreement with those determined by previous measurements. The half-life of elimination was 7.5 hr. The urinary recovery of unchanged drug was approximately 25% of the administered dose.

Carbonic Anhydrases↗

Plasma clonidine concentration and pharmacologic effect.

Analysis of sequential plasma samples in 14 hypertensive subjects receiving their usual oral dose of clonidine (0.1 to 0.6 mg twice daily) indicated that clonidine plasma concentration increased for the first 2 hr and then decreased and stabilized over the next 12 hr. Percent fall in diastolic blood pressure, but not side effects, correlated well with plasma concentration. Our study indicates a potential role for plasma clonidine determination in the treatment of patients with hypertension. It also demonstrates that clonidine can probably be given at 12-hr intervals and be effective.

Adult↗

Difference in nitroglycerin dose-response in the venous and arterial beds.

In twelve healthy volunteers given nitroglycerin sublingually (1.6 mg) or epicutaneously (12 mg), venous distensibility was found to be maximal, even at low plasma concentrations (less than 0.2 ng/ml); there was no further change with increasing concentrations. Peripheral arterial resistance, on the other hand, decreased progressively with rising plasma concentrations and no distinct plateau was demonstrable, even at the highest plasma concentration measured (greater than 2.0 ng/ml).

Adult↗

Determination of submicrogram quantities of clonidine in biological fluids.

A sensitive and specific GLC method using electron-capture detection was developed for clonidine in plasma and urine. Di-perfluoroacyl derivatives of both clonidine and the 4-methyl analog of clonidine (used as an internal standard) were formed, and an extraction process was developed for the removal of excess derivatization reagent and endogenous biological compounds; the assay permitted quantification of 25 pg of clonidine/ml in a 4-ml plasma sample. The assay was used to elucidate the time course of plasma concentrations in a normotensive subject following oral administration of 50, 100, and 200 microgram of clonidine hydrochloride and also to determine unchanged drug excreted in the urine.

Chromatography, Gas↗

Subnanogram assay for pilocarpine in biological fluids.

A method for the determination of pilocarpine was developed in which the imidazole ring of pilocarpine was acylated with heptafluorobutyric anhydride, using triethylamine as a catalyst. After cleanup, the pilocarpine derivative was analyzed using GLC with electron-capture detection. The limit of sensitivity was 25-50 pg of pilocarpine, which had been subjected to the derivatization and cleanup procedures. The method was specific for pilocarpine, with the isopilocarpine derivative eluting prior to the pilocarpine derivative.

Animals↗

Adenosine inhibition of lymphocyte-mediated cytolysis: possible role of cyclic adenosine monophosphate.

The in vitro destruction of tumor cells by specifically sensitized mouse lymphocytes was inhibited by adenosine; this inhibition was markedly potentiated by the presence of an inhibitor of adenosine deaminase. The inhibition of cytolysis by adenosine was accompanied by a rapid elevation in lymphocytic adenosine 3',5'-monophosphate (cyclic AMP) concentrations. Both the inhibition of cytolysis and the elevation of cyclic AMP were reversed by prolonged incubation of the lymphocytes in the presence of adenosine or, more rapidly, by removal of the adenosine. Low concentrations of adenosine also caused an elevation of cyclic AMP in human lymphocytes, and this effect of adenosine may contribute to the lack of immune response associated with adenosine deaminase deficiency.

Adenosine↗