Biomedical subjects

Hongmin Zhang

Publications and source records attributed to Hongmin Zhang.

6 recordsLinked to original sources

PubMed2026

A validated sensitive LC-MS/MS method and its application in elucidating the unique ocular pharmacokinetic profile of 0.01% atropine underpinning its clinical utility for myopia.

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to quantify atropine in ten rabbit ocular tissues enabling systematic characterization of the ocular pharmacokinetic profile of 0.01% atropine sulfate eye drops after a single topical administration. The method demonstrated excellent linearity (coefficient of determination, R2 ≥ 0.9908) across all matrices, with lower limits of quantification (LLOQ) of 0.05 ng/mL for most tissues and 0.10 ng/mL for retina and lens; intra- and inter-day accuracy, precision, matrix effects, extraction recoveries, and stability all met the acceptance criteria. Following a single bilateral topical dose (50 μL/eye) in New Zealand White rabbits, atropine distributed rapidly into all 12 ocular compartments (the sclera further divided into three anatomical regions) with marked heterogeneity-the highest exposures were found in conjunctiva and cornea, a distinct anterior-to-posterior concentration gradient was observed in the sclera, sustained retention was noted in the retina (mean residence time from zero to the last measurable time point, MRT0-t 3.30 h), while aqueous and vitreous humor eliminated rapidly (elimination half-life, t₁/₂ < 0.7 h), and all tissues except aqueous humor followed a two-compartment model. This validated method and the comprehensive pharmacokinetic data reveal that topically applied 0.01% atropine achieves sustained exposure in key myopia-regulating tissues (retina, choroid, posterior sclera) with low exposure in side-effect target tissues (iris, ciliary body, lens).

Animals↗

PubMed2006

Danggui-Buxue-Tang decoction has an anti-inflammatory effect in diabetic atherosclerosis rat model.

Danggui-Buxue-Tang (DBT) is a famous traditional Chinese formula. We examined the anti-inflammatory effect of it in diabetic atherosclerosis rats. DBT (3 or 6g/kg/day for 4 weeks) was orally administrated to the diabetic atherosclerosis rats, which were induced by nitric oxide inhibition (l-NAME in drinking water, 1mg/ml) plus high-fat diet. The concentrations of circulating inflammatory markers C-reactive protein (CRP) and tumour necrosis factor-alpha (TNF-alpha) and serum fructosamine were determined. The results showed that DBT had no direct effect in lowering serum fructosamine level, but can decrease the concentrations of CRP and TNF-alpha, produce a higher survival rate and less body weight loss, and decrease water intake in diabetic atherosclerosis in GK rats.

Animals↗

PubMed2004

Purification, partial characterization, crystallization and structural determination of AHP-LAAO, a novel L-amino-acid oxidase with cell apoptosis-inducing activity from Agkistrodon halys pallas venom.

A snake-venom protein named AHP-LAAO has been purified from Agkistrodon halys pallas venom using four-stage chromatography. AHP-LAAO is a novel member of the snake-venom L-amino-acid oxidase family. Its amino-acid sequence shows high homology to other members of this family. For L-leucine, the values of k(cat) and K(M) are 31.1 s(-1) and 0.25 mM, respectively. The molecular weight of AHP-LAAO is about 60.7 kDa as determined by MALDI-TOF mass spectrometry. AHP-LAAO can also induce apoptosis of cultured Hela cells. Two sets of diffraction data with similar resolution limits (about 2.5 A) were collected independently at MacCHESS (Cornell High Energy Synchrotron Source, USA) and IHEP (Institute of High Energy Physics, Beijing, China). The crystals belong to space group I2(1)3, with unit-cell parameter a = 169.31 A, corresponding to one molecule in the asymmetric unit and a volume-to-weight ratio of 3.33 A(3) Da(-1). The final structural model is similar to that of L-amino-acid oxidase from Calloselasma rhodostoma venom.

Amino Acid Oxidoreductases↗

PubMed2004

Transcatheter embolization using degradable crosslinked hydrogels.

Therapeutic embolization is the selective transcatheter blockage of blood vessels or diseased vascular structures. The majority of current embolization materials in clinical use are permanent. There are clinical situations however, in which temporary embolization is desired. Degradable hydroxyethyl acrylate (HEA) microspheres have been synthesized. Canine renal arteries and rabbit central auricular arteries were embolized with HEA microspheres, and compared with degradable human serum albumin (HSA) microspheres, and permanent microspheres. HSA and HEA microspheres both achieved temporary occlusions. HSA and HEA microspheres were recanalizated at 1 and 3 weeks, respectively, while arteries occluded with permanent microspheres did not recanalize. All embolic microspheres led to tissue infarction, with the short-term HSA microspheres providing the least damage, and the permanent microspheres leading to extensive damage. Advantages of temporary embolization were not convincingly demonstrated since temporary occlusions still led to tissue infarction.

Absorbable Implants↗

PubMed2004

Hydrogen peroxide produced by two amino acid oxidases mediates antibacterial actions.

The antibacterial actions of two amino acid oxidases, a D-amino acid oxidase from hog kidney and a L-amino acid oxidase from the venom of Agkistrodon halys, were investigated, demonstrating that both enzymes were able to inhibit the growth of both Gram-positive and Gram-negative bacteria, and that hydrogen peroxide, a product of their enzymatic reactions, was the antibacterial factor. However, hydrogen peroxide generated in the enzymatic reactions was not sufficient to explain the degree to which bacterial growth was inhibited. A fluorescence labeling assay showed that both of these two enzymes could bind to the surfaces of bacteria. To the best of our knowledge, this is the first report regarding the antibacterial activity of the D-amino acid oxidases.

Agkistrodon↗

PubMed2002

[The change of immunoglobulin in patients with eyeball perforation at high altitude].

OBJECTIVE: To explore the change of tear immune function on eyeballs with perforating injury at high altitude. METHODS: In 51 patients (53 eyes) with eyeball perforating injury at high altitude (sea level 3658 m), by using single agar immune diffusion test, IgG, IgA, IgM, C(3) and C(4) values of tears were separately measured before and after clinical cure. RESULTS: The Ig values of tears increased universally. The IgA value increased especially in the 7th day. The IgG and IgM value in the serum increased in the 3rd day after injury (P < 0.05), and the IgG, IgA and IgM of tears increased especially on the 7th day (P < 0.01). The C(3) and C(4) value of tears did not change significantly (P < 0.05). CONCLUSIONS: The change of Ig value is a useful detective means to evaluate the treatment effect.

Adolescent↗