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Biomedical subjects

H Luo

Publications and source records attributed to H Luo.

At least 199 records · Page 11Linked to original sources
PubMed1995

N(+)-glucuronidation of aliphatic tertiary amines in human: antidepressant versus antipsychotic drugs.

1. Metabolic N(+)-glucuronidation of aliphatic tertiary amine antidepressant or antipsychotic drugs was investigated in man. In each case, urine was collected either from patients and/or from healthy volunteers who were administered the drug orally. 2. Metabolites were separated by hplc and individually collected prior to mass spectrometric analysis in the fast atom bombardment mode. The structure of each metabolite identified as a quaternary ammonium-linked glucuronide metabolite was confirmed by direct comparison of its mass spectrum and chromatographic behaviour with that of an authentic standard synthesized in these laboratories. 3. Of the 10 antipsychotic drugs examined clozapine and loxapine were the only two for which the N(+)-glucuronidation pathway was observed, whereas all four antidepressants gave the respective N(+)-glucuronide metabolite. 4. The N(+)-glucuronide metabolites in 24 h urine samples were quantified by hplc. The mean (n = 3) percentage of the dose excreted as the metabolite was found to be 1.6 and 3.1% in the cases of the antipsychotic agents loxapine and clozapine respectively, whereas for the antidepressants clomipramine, imipramine, trazodone and trimipramine these means varied between 0.1 and 0.8%.

Antidepressive Agents↗
PubMed1995

Evidence for a retroviral trigger in Graves' disease.

An apparently high frequency of Graves' disease encountered in New Orleans, Louisiana, prompted an investigation for a possible infectious agent that might be triggering the disease in genetically susceptible individuals. We studied 40 patients with Graves' disease, and compared them to the following groups of controls: age and gender matched healthy subjects; patients with multinodular goiter (non-autoimmune thyroid controls); patients with chronic lymphocytic thyroiditis (autoimmune thyroid disease controls) and additional organ or tissue specific autoimmune controls exclusive of thyroid autoimmunity, including patients with Type I diabetes and other endocrine autoimmune complex disorders. Serum antibodies against a prototypic strain of a human intracisternal A-type retroviral particle type 1 (HIAP-1) were detected by a sensitive and specific immunoblotting assay. In 87.5% (35/40) of the Graves' disease patients there was a positive reaction against several HIAP-1-associated proteins, predominantly 97 Kd and 80 Kd, with only 5 showing no reactivity to any. In contrast, 2% (2/105) of sera from normal controls showed positive reactivity. Furthermore, only 10% (1/10) of sera from multinodular goiter control patients and 10% (1/10) of Hashimoto's patients showed reactivity (p < 0.0005). Sera from 3 of 20 (15%) of Type I diabetic patients none of whom had Graves' disease, showed reactivity but there was no reactivity in 9 other patients with one or more of the endocrine autoimmune complex disorders, including Addison's disease, vitiligo, myasthenia gravis and pernicious anemia. In addition we studied two individuals with Graves' disease from each of two families residing outside Louisiana, all of whom were positive for these antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[A new and simple method of evaluating left ventricular contractility and its application].

After making theoretical analysis, we detected the relationship among the maximal tension of ventricular contraction, left ventricular end-systolic pressure and stroke volume, and then derived a new and simple method of evaluating left ventricular contractility, the slope of the left ventricular end-systolic pressure-volume relation (Emax). Twelve mongrel male dogs were used to test this method. The results show that the value of Emax (0.60 +/- 0.16 kPa/ml) coming from this simple method is very close to that from complicated method; this method has good repetitiveness and is very sensitive to the variation of myocardial contraction. Using the method for evaluating left ventricular contraction after ischemia, we found the Emax more cogent than other hemodynamic parameters. Therefore, this method is an efficient method of evaluating left ventricular contraction.

Animals↗
PubMed1995

Motor blockade and absence of local nerve toxicity induced by liposomal bupivacaine injected into the brachial plexus of rabbits.

Bupivacaine has been encapsulated into multilameller liposomes in order to reduce its systemic toxicity and to lengthen its action. Low, constant and sustained plasma levels have been observed after epidural injection and brachial plexus administration to rabbits. The present experiment was performed in order to study the motor block effect and the possible neurotoxicity of bupivacaine encapsulated in multilamellar liposomes applied in vivo to intact peripheral nerve bundles. Five milliliters of sterile solutions containing 0.75% bupivacaine encapsulated in 42.5 and 85 mg of lipids (phosphatidylcholine and cholesterol in a molar ratio 4:3) were administered to 4 rabbits at the level of the brachial plexus. A motor blockade of the forelimb lasting for 10 hours was measured immediately after injection of the liposomal drug. Light microscopic analyses of the nerves after 2 and 7 days revealed weak inflammatory perineural infiltration. Electron microscopy showed no changes of the myelin sheaths and no alteration of unmyelinated fibers. It may be concluded that the pharmacologically active liposomal formulation of bupivacaine did not induce alterations of the nerve tissues.

Animals↗
PubMed1995

[Anti-lipid peroxidation effects of sini decoction and its components on ischemic myocardium and the dose- and time-effects].

The complete Sini Decoction can significantly reduce the content of MDA in ischemic myocardium. Single ingredients of the decoction, such as Radix Aconoti Praeparata or Radix Glycyrrhizae, except Rhizoma Zingiberis, also have similar effect but inferior to that of the complete decoction. Under the present conditions of experiment, anti-lipid peroxidation of Sini Decoction is significant at doses ranging from 0.05 to 0.2ml/20g administered for 2-7 days at 0.1ml/(20g.d).

Animals↗
PubMed1995

Infection characteristics of an Ecuadorian Trypanosoma cruzi strain with reduced virulence.

A human isolate of Trypanosoma cruzi obtained from Guayaquil, Ecuador (Guayas strain) was examined for its infectivity of the resistant C57Bl/6 (B6) and the susceptible C3H (He) mouse strains and compared to infection with the known virulent Brazil strain. C3H mice were capable of surviving acute Guayas infection, whereas the Brazil infection was fatal for this mouse strain. Both C3H and B6 mice showed a greatly reduced (over 10-fold) parasitemia during Guayas infection compared to Brazil infection. Histologic examination of heart tissue from Guayas-infected B6 and C3H mice indicates little inflammation, unlike what is typically seen in B6 mice chronically infected with the Brazil strain. There appears to be no remarkable difference in the anti-parasite antibody responses (as measured by ELISA and western blot) in mice infected 100 days with Guayas or Brazil parasites. Western blot analysis of the anti-heart response indicates no response during Guayas infection to a 43-kDa heart tissue glycoprotein that is a target of antibodies from B6 mice infected with Brazil strain. The Guayas strain, therefore, provides an infection that generates a low parasitemia and strong anti-parasite responses in the absence of specific anti-heart autoimmunity and obvious myocarditis. In vitro infection characteristics of these 2 parasite strains were studied in cultures of macrophages, myocytes, and fibroblasts by microscopic examination of stained slide cultures. In both short-term (24 hr) and long-term (15 day) experiments, Brazil strain infection was shown to have a greater infection rate with a higher number of parasites per cell than Guayas infection for all host cell types.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[In vitro experiment on scavenging oxy-radical and suppressing myocardial lipid peroxidation with sini decoction].

Results indicate that Sini Decoction has a significant effect of anti-lipid peroxidation of its components, Radix Aconiti Preparata and Radix Glycyrrhizae can significantly suppress lipid peroxidation of myocardial homogenate, while Rhizoma Zingiberis cannot. The decoction can effectively scavenge oxygen free radicals, each component having similar effect to some extent.

Animals↗
PubMed1994

High intensity, low frequency catheter-delivered ultrasound dissolution of occlusive coronary artery thrombi: an in vitro and in vivo study.

OBJECTIVES: This study assessed the efficacy of a new high intensity, low frequency therapeutic coronary ultrasound catheter for thrombus dissolution in vitro and in vivo in canine coronary arteries. BACKGROUND: Therapeutic ultrasound has been shown to dissolve thrombi in vitro and in peripheral arteries in vivo. There have been no previous studies on in vivo coronary thrombus dissolution by ultrasound. METHODS: In vitro, we exposed 1- to 4-h old human blood clots for 3 min to pulsed-wave ultrasound. Clot dissolution under various conditions was evaluated. In vivo occlusive coronary thrombi were induced in 18 dogs. RESULTS: In vitro irrigation alone (10 ml/min of normal saline solution) and ultrasound alone each contributed to a reduction of clot weight by 47.1 +/- 11.4 mg and 84.6 +/- 25.6 mg, respectively, after 3 min (p < 0.001). Ultrasound plus irrigation resulted in a reduction of clot weight by 216.5 +/- 31.5 mg after 3 min (p < 0.001). The magnitude of clot dissolution was considerably amplified when ultrasound energy was combined with irrigation, probably because of cavitational effects. In vivo, in three dogs mechanical passage of the unactivated probe failed to recanalize the artery, and the arteries remained thrombotically occluded. After passage of the activated ultrasound probe, angiography revealed widely patent coronary arteries in 13 of 15 dogs and partial recanalization with filling defects indicative of residual thrombus in 2 of 15 dogs. Three of 15 coronary arteries were histologically free of residual thrombi. Mural thrombi extending to < or = 10% of the vessel circumference were seen in 10 of 15 dogs. Residual thrombi > or = 50% of the vessel circumference were found in two cases. There was no histologic evidence of ultrasound-mediated vessel damage. CONCLUSIONS: Catheter-delivered therapeutic ultrasound effectively dissolves clots in vitro and in canine coronary arteries in vivo. Thus, therapeutic catheter-delivered ultrasound has the potential to serve as an adjunct or alternative treatment for thrombus-mediated coronary ischemic syndromes or myocardial infarction.

Animals↗