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Biomedical subjects

H Sun

Publications and source records attributed to H Sun.

At least 361 records · Page 20Linked to original sources
PubMed1996

On the recording of sample times and parameter estimation from repeated measures pharmacokinetic data.

A pharmacokinetic screen has been advocated for the characterization of the population pharmacokinetics of drugs during Phase 3 clinical trials. A common perception encountered in the collection of such data is that the accuracy of sampling times relative to dose is inadequate. A prospective simulation study was carried out to evaluate the effect of error in the recording of sampling times on the accuracy and precision of population parameter estimates from repeated measures pharmacokinetic data. A two-compartment model with intravenous bolus input(s) (single and multiple doses) was assumed. Random and systematic error in sampling times ranging from 5-50% using profile (block) randomized design were introduced. Sampling times were simulated in EXCEL while concentration data simulation and analysis were done in NONMEM. The effect of error in sampling times was studied at levels of variability ranging from 15-45% for a drug assumed to be dosed at its elimination half-life. One hundred replicate data sets of 100 subjects each were simulated for each case. Although estimates of clearance (CL) and variability in clearance were robust for most of the sampling time errors, there was an increase in bias and imprecision in overall parameter estimation as intersubject variability was increased. If there is interest in parameters other than CL, then the design of prospective population studies should include procedures for minimizing the error in the recording of sample times relative to dosing history.

Computer Simulation↗
PubMed1996

Immunoregulation of lupus-like NZB/W F1 mice by anti-murine IL-1 alpha, IL-6 antibodies.

Anti-murine IL-1 alpha, IL-6 antibodies were intra-peritoneally injected to the lupus-like NZB/W F1 mice of 4 months with the dosage of 10 micrograms per day for three days and then per month for three months. The mice were killed at the age of 11 months. The results showed that the treatment of the dosage could not absolutely prevent lupus nephritis--it could alleviate proteinuria, obviously reduce the levels of serum IL-1 alpha and inhibit the secretion of IL-1 alpha by celiac macrophage. As to the level of IL-6 and TNF-alpha no significant change was observed.

Animals↗
PubMed1996

Study of heat shock protein HSP90 alpha, HSP70, HSP27 mRNA expression in human acute leukemia cells.

The expression of three heat shock proteins (HSPs)-HSP90 alpha, HSP70, HSP27 in cells obtained from 22 patients with leukemia, K562 erythroleukemia cell line, and normal blood cells was observed by means of RNA dot blot analysis. The results showed that the expression of the HSP27 gene was enhanced in 4 cases of acute lymphoid leukemia (ALL), 7 cases of acute nonlymphoid leukemia (ANLL) and 2 cases of myelodysplastic syndrome (MDS) as compared with that of the normal blood cells, yet there was no significant difference in the HSP27 expression between the ALL and ANLL cells. The expression of HSP70 in all the 5 ALL and ANLL patients was much lower than that of the normal subjects, except 1 case of ALL and 1 case of MDS, in which the expression was obviously enhanced. All the cases including 11 ANLL, 5 ALL and 1 MDS had higher HSP90 alpha expression than the normal subjects. The enhanced expression of HSP90 alpha in leukemia cells may be associated with the active and indefinite proliferation of leukemia cells. Our results also suggest that the high expression of the HSP27 gene may not be confined to a specific type of acute leukemia.

HSP70 Heat-Shock Proteins↗
PubMed1996

Clinical neuroimmunology.

Clinical research has focused on autoimmune disease (AID) for a couple of decades. More sensitive and specific methods have been developed for neuroimmunological research. Gamma fraction bands (bands separated by electrophoresis and visualized by amino black staining) and IgG fraction bands (bands separated by iso-electric focusing and visualized by immunostaining) are used instead of oligoclonal bands. Myasthenia gravis (MG) mainly involves acetylcholine receptors of the postsynaptic membrane at the neuromuscular junction. Myasthenia gravis has been considered to be a generalized AID, because 7% of patients with myasthenia gravis associate with other AIDs and more than one autoimmune antibody is detected in 52.5% patients with myasthenia gravis. Pyramidal signs in myasthenia gravis patients are described; the possible mechanism may at least be partly due to the acetylcholine receptor antibody. P2 protein and its antibody are studied in patients with acute and chronic inflammatory demyelinating polyneuropathy.

Adolescent↗
PubMed1996

Antifibrillatory effect of esmolol alone and in combination with lidocaine.

The primary objective of this study was to determine the effect of esmolol, administered alone and in combination with lidocaine, on ventricular fibrillation threshold (VFT) in pigs. A secondary objective was to determine the relationship between blood esmolol concentrations and VFT. We determined VFT using a train of electrical stimuli delivered to the right ventricle after eight paced beats at a basic cycle length of 285 ms. Current was increased in 2-mA increments until VF occurred. VFT determinations were performed during administration of esmolol 1,000 mu g/kg/min, during a continuous infusion of lidocaine, and during infusion of esmolol and lidocaine in combination. Mean increases in VFT from baseline during infusion of esmolol and lidocaine alone were 32.3 +/- 12.9 and 8.5 +/- 7.2 mA, respectively (p < 0.05, each drug compared with baseline; p < 0.05, esmolol vs. lidocaine). Mean increase in VFT from baseline during infusion of the combination was 52.0 +/- 22.0 mA (p < 0.05 as compared with baseline and with esmolol or lidocaine alone). The relationship between blood esmolol concentrations and VFT was described by a counterclockwise hysteresis curve, suggesting delay in equilibration of esmolol between blood and site of effect. The antifibrillatory efficacy of esmolol is significantly greater than that of lidocaine in this model. Administration of the two agents in combination resulted in significantly greater antifibrillatory efficacy than that associated with either drug administered alone.

Adrenergic beta-Antagonists↗
PubMed1996

Characterization of the African swine fever virion protein j18L.

The African swine fever virus (ASFV) open reading frame (ORF) that is named jl8L in the Malawi (LIL20/1) isolate and E199L in the Ba71V isolate encodes a cysteine rich protein of 195 amino acids with a predicted molecular mass of 21.7 kDa and a hydrophobic domain near the C terminus. There are several possible motifs for glycosylation, phosphorylation and myristoylation. Rabbit antisera and monoclonal antibodies raised against a recombinant ASFV j18L protein expressed as a fusion protein with glutathione S-transferase (GST) identified proteins of 19.0-20 kDa in cells infected with different ASFV strains and with a recombinant vaccinia virus expressing j18L. The monoclonal antibodies detected a protein of 20.0 kDa whereas rabbit antisera detected two proteins with relative molecular masses of 15.0 and 20.0 kDa in purified extracellular ASF virions. In ASFV-infected cells, the j18L protein was expressed late post-infection and was localized mainly in the viral factories.

African Swine Fever Virus↗
PubMed1996

Two new saponins, congmuyenosides A and B, from the leaves of Aralia elata collected in Heilongjiang, China.

Two new triterpenoidal saponins, congmuyenosides A and B, were isolated from the leaves of Aralia elata collected in Heilongjiang Province, China, and established as 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D-glucopyranosyl-(1-->3)]- beta-D-glucopyranosyl hederagenin and 3-O-[beta-D-glucopyranosyl(1-->2))] [beta-D-glucopyranosyl(1-->3)-beta-D-glucopyranosyl(1-->3 )]-beta-D-glucopyranosyl hederagenin, respectively, on the basis of chemical and spectral evidence.

Carbohydrate Sequence↗
PubMed1996

Diabetes increases sciatic nerve susceptibility to endothelin-induced ischemia.

Endothelin-1 (ET) is a potent vasoconstrictor of vasa nervorum, the vascular supply of peripheral nerve trunks, that may, through elevated circulating levels, promote microangiopathy in human diabetes patients. In previous work, we observed that sciatic nerve trunks of rats exposed to epineurial ET developed transient dose-dependent endoneurial ischemia that might be associated with reversible motor conduction block. In the present study, we explored the possibility that ET ischemia might selectively damage axons of diabetic nerve trunks. We exposed the sciatic nerves of rats with streptozotocin-induced diabetes of 6-8 weeks duration and age-matched nondiabetic controls to supramaximal vasoconstrictive concentrations of epineurial ET and studied serial regional erythrocyte flux (laser Doppler flowmeter) and sciatic tibial motor conduction for up to 14 days. In diabetic rats, but not controls, ET ischemia damaged a large proportion of sciatic axons, predicted in each instance by focal motor conduction block across the site of ET application and eventual loss of distal motor nerve excitability. Histological studies confirmed the presence of severe axonal degeneration in diabetic sciatic nerves exposed to ET. Part of the susceptibility to ET in diabetes was accounted for by more intense and prolonged vasoconstriction. Diabetic nerves are selectively susceptible to ET-mediated ischemia.

Animals↗
PubMed1996

The evolution and current status of China's Tibetan population.

"Through analyses on the changes in the mortality rate, total population size, regional population distribution, gender-specific age structure, and the population nationality structure in major habitats of Tibetan residents since the founding of the People's Republic, this article shows that the Tibetan population size has been on the steady increase, mortality rate has seen marked decrease, and the rights of existence of Tibetan people have been fully guaranteed since the establishment of the Communist Government in 1949."

Age Distribution↗