Gender difference of alanine aminotransferase elevation may be associated with higher hemoglobin levels among male adolescents

Background

To explore the gender difference of ALT elevation and its association with high hemoglobin levels.

Methods

A cross-sectional study of 3547 adolescents (2005 females, mean age of 16.5?.3 years) who were negative for hepatitis B surface antigen received health checkups in 2006. Body mass index (BMI), levels of hemoglobin, ALT and cholesterol were measured. ALT >42 U/L was defined as elevated ALT. Elevated ALT levels were detected in 112 of the 3547 participants (3.3%), more prevalent in males than in females (5.4% vs. 1.4%, p<0.001). Hemoglobin levels had a significant linear correlation with ALT levels in both genders. Abnormal ALT started to occur if hemoglobin >11 g/dl in females or >13.5 g/dl in males, but the cumulative cases of elevated ALT increased more quickly in males. Proportion of elevated ALT increased as either the BMI or hemoglobin level rise, more apparent in male adolescents. Logistic regression modeling showed odds ratio (95% confidence interval) were 24.7 (15.0–40.6) for BMI ≥27 kg/m²; 5.5 (2.9–10.4) for BMI 24–27 kg/m²; 2.7 (1.3–5.5) for Q5 (top 20th percentile) hemoglobin level; and 2.6 (1.6–4.1) for male gender. Further separately fitting the logistic models for two genders, the significance of Q5 hemoglobin level only appeared in the males.

Conclusions

High hemoglobin level is a significant risk factor of ALT elevation after control hepatitis B, obesity and gender. Males have greater risk of abnormal liver function which may be associated with higher hemoglobin levels.     

Kinetics of the growth of Toxoplasma gondii (RH strain) in mice.

A method is described for obtaining maximum yield of Toxoplasma tachyzoites from the peritoneal cavity of infected mice. Mice injected with 10² parasites contain more Toxoplasma in this site at the time of death than mice injected with larger numbers. The host does not mount a detectable humoral response to the parasite.     

Human immunodeficiency virus type 2 envelope glycoprotein binds to CD8 as well as to CD4 molecules on human T cells.

We report here that human immunodeficiency virus type 2 (HIV-2) envelope glycoprotein (gp105), but not HIV-1 gp120, can bind to CD8 molecules as well as to CD4 molecules on human T cells. This phenomenon may lead to differences in the life cycles of HIV-1 and HIV-2, and it may be related to the differences in disease manifestations of HIV-1 and HIV-2 infection, including longer survival of HIV-2-infected patients.     

Functional polymer brushes via surface-initiated atom transfer radical graft polymerization for combating marine biofouling

Dense and uniform polymer brush coatings were developed to combat marine biofouling. Nonionic hydrophilic, nonionic hydrophobic, cationic, anionic and zwitterionic polymer brush coatings were synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP) of 2-hydroxyethyl methacrylate, 2,3,4,5,6-pentafluorostyrene, 2-(methacryloyloxy)ethyl trimethylammonium chloride, 4-styrenesulfonic acid sodium and N,N'-dimethyl-(methylmethacryloyl ethyl) ammonium propanesulfonate, respectively. The functionalized surfaces had different efficacies in preventing adsorption of bovine serum albumin (BSA), adhesion of the Gram-negative bacterium Pseudomonas sp. NCIMB 2021 and the Gram-positive Staphylococcus aureus, and settlement of cyprids of the barnacle Amphibalanus amphitrite (=Balanus amphitrite). The nonionic hydrophilic, anionic and zwitterionic polymer brushes resisted BSA adsorption during a 2?h exposure period. The nonionic hydrophilic, cationic and zwitterionic brushes exhibited resistance to bacterial fouling (24?h exposure) and cyprid settlement (24 and 48?h incubation). The hydrophobic brushes moderately reduced protein adsorption, and bacteria and cyprid settlement. The anionic brushes were least effective in preventing attachment of bacteria and barnacle cyprids. Thus, the best approach to combat biofouling involves a combination of nonionic hydrophilic and zwitterionic polymer brush coatings on material surfaces.     

Inhibition of Escherichia coli and Proteus mirabilis adhesion and biofilm formation on medical grade silicone surface

Silicone has been utilized extensively for biomedical devices due to its excellent biocompatibility and biodurability properties. However, its surface is easily colonized by bacteria which will increase the probability of nosocomial infection. In the present work, a hydrophilic antimicrobial carboxymethyl chitosan (CMCS) layer has been grafted on medical grade silicone surface pre-treated with polydopamine (PDA). The increase in hydrophilicity was confirmed from contact angle measurement. Bacterial adhesion tests showed that the PDA-CMCS coating reduced the adhesion of Escherichia coli and Proteus mirabilis by ≥ 90%. The anti-adhesion property was preserved even after the aging of the functionalized surfaces for 21 days in phosphate-buffered saline (PBS), and also after autoclaving at 121°C for 20 min. Both E. coli and P. mirabilis readily form biofilms on the pristine surface under static and flow conditions but with the PDA-CMCS layer, biofilm formation is inhibited. The flow experiments indicated that it is more difficult to inhibit biofilm formation by the highly motile P. mirabilis as compared to E. coli. No significant cytotoxicity of the modified substrates was observed with 3T3 fibroblasts.     

Antioxidant and antibacterial activities of eugenol and carvacrol‐grafted chitosan nanoparticles

Essential oils are known to possess antimicrobial and antioxidant activity while chitosan is a biocompatible polymer with antibacterial activity against a broad spectrum of bacteria. In this work, nanoparticles with both antioxidant and antibacterial properties were prepared by grafting eugenol and carvacrol (two components of essential oils) on chitosan nanoparticles. Aldehyde groups were first introduced in eugenol and carvacrol, and the grafting of these oils to chitosan nanoparticles was carried out via the Schiff base reaction. The surface concentration of the grafted essential oil components was determined by X‐ray photoelectron spectroscopy (XPS). The antioxidant activities of the carvacrol‐grafted chitosan nanoparticles (CHCA NPs) and the eugenol‐grafted chitosan nanoparticles (CHEU NPs) were assayed with diphenylpicrylhydrazyl (DPPH). Antibacterial assays were carried out with a representative gram‐negative bacterium, Escherichia coli (E. coli) and a gram‐positive bacterium, Staphylococcus aureus (S. aureus). The grafted eugenol and carvacrol conferred antioxidant activity to the chitosan nanoparticles, and the essential oil component‐grafted chitosan nanoparticles achieved an antibacterial activity equivalent to or better than that of the unmodified chitosan nanoparticles. Cytotoxicity assays using 3T3 mouse fibroblast showed that the cytotoxicity of CHEU NPs and CHCA NPs were significant lower than those of the pure essential oils. Biotechnol. Bioeng. 2009; 104: 30–39 © 2009 Wiley Periodicals, Inc.     

Surface functionalization of polypyrrole film with glucose oxidase and viologen

A surface modification technique was developed for the functionalization of polypyrrole (PPY) film with glucose oxidase (GOD) and viologen moieties. The PPY film was first graft copolymerized with acrylic acid (AAc) and GOD was then covalently immobilized through the amide linkage formation between the amino groups of the GOD and the carboxyl groups of the grafted AAc polymer chains in the presence of a water-soluble carbodiimide. Viologen moieties could also be attached to the PPY film via graft-copolymerization of vinyl benzyl chloride with the PPY film surface followed by reaction with 4,4'-bipyridine and alpha,alpha'-dichloro-p-xylene. X-ray photoelectron spectroscopy (XPS) was used to characterize the PPY films after each surface modification step. Increasing the AAc graft concentration would allow a greater amount of GOD to be immobilized but this would decrease the electrical conductivity of the PPY film. The activity of the immobilized GOD was compared with that of free GOD and the kinetic effects were also studied. The immobilized GOD was found to be less sensitive to temperature deactivation as compared to the free GOD. The results showed that the covalent immobilization technique offers advantages over the technique involving the entrapment of GOD in PPY films during electropolymerization. The presence of viologen in the vicinity of the immobilized GOD also enabled the GOD-catalyzed oxidation of glucose to proceed under UV irradiation in the absence of O(2).     

Physicochemical and blood compatibility characterization of polypyrrole surface functionalized with heparin

A surface modification technique was developed for the covalent immobilization of heparin onto electrically conductive polypyrrole (PPY) film. The PPY film was first graft copolymerized with poly(ethylene glycol) methacrylate (PEGMA) and then activated with cyanuric chloride (CC). Heparin was then immobilized onto the film through the reaction between the chloride groups of CC and the amine and/or hydroxyl groups of heparin. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface-modified film after each stage. The biocompatibility of the surface-modified PPY was evaluated using plasma recalcification time (PRT) and platelet adhesion. After surface modification, the film had improved wettability while retaining significant electrical conductivity. With immobilized heparin, platelet adhesion and platelet activation on PPY film was significantly suppressed, and the PRT was significantly prolonged. Electrical stimulation also plays a positive role in decreasing platelet adhesion and increasing PRT on pristine and surface-modified PPY films.