Synergistic effects of polymer adsorbents on the performance of bilirubin hemoperfusion.

Neonatal hyperbilirubinemia (jaundice) is a common disease with high incidence. Currently, the clinical inefficiency of adult bilirubin hemoperfusion medical adsorbent is a major technical barrier for the application of hemoperfusion treatment to rescue the severe neonatal jaundice. Based on the well-known principle of synergistic effects, a series of customized bilirubin polymeric compounds, comprised of one or more of the following components (glycidyl methacrylate, sodium acrylate, methacrylic acid isooctyl, hexamethylene diamine, albumin), were designed and fabricated based on molecular design. Their adsorption performances upon bilirubin were investigated and compared under the same conditions, and the compound with the highest adsorption performance was then subject to preliliminary safety assessments and compared with a commercial one (BS330). The results showed that positive synergistic effects appeared on the adsorption performance to adsorb bilirubin based on this study, and the one comprised of glycidyl methacrylate+sodium acrylate+methacrylic acid isoocty+hexamethylene diamine+albumin possesses the highest adsorption performance as well as outome clinical acceptable medical safety assessments, and its adsorption efficiency was up to 46% while the commerical one's was about 26% under the same conditions. This study sheds a new light on how to design and develop hemoperfusion bilirubin adsorbents with good overall clinical performance, as well as providing a novel idea and experimental referrences for future related topics.

Effects of T-2 toxin on the regulation of steroidogenesis in mouse Leydig cells.

T-2 toxin is one of the mycotoxins, a group of type A trichothecenes produced by several fungal genera including Fusarium species, which may lead to the decrease of testosterone secretion in primary Leydig cells derived from mouse testis. The previous study demonstrated T-2 toxin decrease the testosterone biosynthesis in the primary Leydig cells derived from the mouse testis directly. In this study, we further examined the direct biological effects of T-2 toxin on the process of steroidogenesis, primarily in Leydig cells of mice. Leydig cells of mature mouse were purified by Percoll gradient centrifugation and the cell purity was determined by 3ß-hydroxysteroid dehydrogenase (3ß-HSD) staining. To examine the decrease in T-2 toxin-induced testosterone secretion, we measured the transcription level of three key steroidogenic enzymes including 3ß-HSD-1, cytochrome P450 side-chain cleavage (P450scc) enzyme, and steroidogenic acute regulatory (StAR) protein in T-2 toxin/human chorionic gonadotropin (hCG) co-treated cells. Our previous study showed that T-2 toxin (10(-7), 10(-8), and 10(-9) M) significantly suppressed hCG (10 ng/ml)-induced testosterone secretion. The studies demonstrated that the suppressive effect is correlated with a decrease in the level of transcription of 3ß-HSD-1, P450scc, and StAR (p < 0.05).

T-2 toxin inhibits gene expression and activity of key steroidogenesis enzymes in mouse Leydig cells.

T-2 toxin is one of the mycotoxins, a group of type A trichothecenes produced by several fungal genera including Fusarium species, which may lead to the decrease of the testosterone secretion in the primary Leydig cells derived from the mouse testis. The previous study demonstrated the effects of T-2 toxin through direct decrease of the testosterone biosynthesis in the primary Leydig cells derived from the mouse testis. In this study, we further examined the direct biological effects of T-2 toxin on steroidogenesis production, primarily in Leydig cells of mice. Mature mouse Leydig cells were purified by Percoll gradient centrifugation and the cell purity was determined by 3ß-hydroxysteroid dehydrogenase (3ß-HSD) staining. To examine T-2 toxin-induced testosterone secretion decrease, we measured the transcription levels of 3 key steroidogenic enzymes and 5 enzyme activities including 3ß-HSD-1, P450scc, StAR, CYP17A1, and 17ß-HSD in T-2 toxin/human chorionicgonadotropin (hCG) co-treated cells. Our previous study showed that T-2 toxin (10(-7) M, 10(-8) M and 10(-9) M) significantly suppressed hCG (10 ng/ml)-induced testosterone secretion. The studies demonstrated that the suppressive effect is correlated with the decreases in the levels of transcription of 3ß-HSD-1, P450scc, and StAR (P<0.05) and also in enzyme activities of 3ß-HSD-1, P450scc, StAR, CYP17A1, and 17ß-HSD (P<0.05).

Heparinized polyvinyl alcohol to specifically adsorb low-density lipoprotein from plasma.

INTRODUCTION: A medical adsorbent for blood purification was developed to specifically adsorb low-density lipoprotein (LDL) from hypercholesterolemia patient's plasma by covalently immobilizing heparin onto the surface of polyvinyl alcohol (PVA) with the couplant toluence-2,4-diisocyanate (TDI). METHODS: We used IR to demonstrate the success of covalently immobilizing heparin onto the surface, and investigated its adsorption of LDL, and primarily evaluated its hemo-compatibility using tests for platelet adhesion, the degree of platelet activation and a hemolysis test. RESULTS: (1) Heparin was successfully covalently immobilized onto the surface, the maximum amount of heparin immobilized on the surface of 1g PVA-1799 granules was about 5 µg; (2) one optimal condition for adsorption of LDL from hyperlipidemia plasma was a pH within the range of 7.2∼9.5, accordingly the adsorptive ratio (adsorbent/g: plasma/L=1:2) for LDL was about 70%; (3) it exhibited good hemo-compatibility. CONCLUSION: The adsorbent results in satisfactory adsorption of LDL with good hemo-compatibility; it could potentially be used as a blood purification material, and immobilization of heparin onto medical materials may be a way to develop an LDL-specific adsorbent for blood purification.

Toxic effects of T-2 toxin on reproductive system in male mice.

The present study was conducted to evaluate the effects of T-2 toxin on semen quality, fertility and serum testosterone concentration in mice. Adult male mice were mated with sexually mature untreated female mice after being exposed to intraperitoneal injection of T-2 toxin at 0, 5, 10 or 15 mg/kg body weight daily for 7 successive days. Semen quality, serum testosterone concentration and fertility of treated mice were assessed. The results showed that the number of abnormal spermatozoa increased significantly and a significant decrease in spermatozoa with integrated acrosome was observed in males treated with T-2 toxin at all doses, As well, the amount of live spermatozoa decreased significantly in mice treated with 10 and 15 mg/kg body weight T-2 toxin. Low pregnancy rate and high fetal resorption rate were observed when females were mated with T-2 toxin-exposed males. Testicular and cauda epididymal sperm counts, efficiency of sperm production and serum testosterone concentration were significantly reduced in mice treated with T-2 toxin at all doses in a dose-dependent manner. In conclusion, these findings indicated that T-2 toxin presented toxic effects on reproductive system of adult male mice.

Preparation of heparin-immobilized PVA and its adsorption for low-density lipoprotein from hyperlipemia plasma.

In this study, heparin was covalently coupled by glutaraldehyde to Poly(vinyl alcohol) [PVA] in solid-liquid two-phase reaction system by two-step synthesis method to prepare a LDL-selective adsorbent. The parameters (the material ratio, reaction time and dosage of catalyzer) were investigated to evaluate their effect upon the immobilized amount of heparin onto the surface of PVA, IR was used to verify the covalent immobilization result and the heparin-modified PVA was also undergone the evaluation of its adsorption capability for low-density lipoprotein from hyperlipemia plasma, and its hemocompatibility was preliminarily evaluated by platelet adhesion test. Results showed: (1) under optimized reaction conditions the highest immobilization amount of heparin onto PVA surface within the experiments of this study has been obtained; (2) the optimized reaction conditions were: (i) at the refluxing temperature 78 degrees C; (ii) the material ratio of "PVA(g): 50% glutaraldehyde (ml)" was about "1:3"; (iii) the reaction time was about 5 h; and (iv) the amount of catalyzer (concentrated HCL) was about 1% of the 50% glutaraldehyde; (3) within the experiments of this study the highest immobilization amount would be up to 25 microg heparin on the surface of per g PVA granules; (4) the heparin-modified PVA granules showed significant adsorption for LDL under faintly alkaline environment (pH=7.2-9.5) ; (5) The result of platelet adhesion test showed no platelet adhered to its surface. Therefore, immobilization of heparin onto the surface of a support is one approach to prepare a kind of LDL adsorbent for blood purification.

Fabrication of a PLGA-collagen peripheral nerve scaffold and investigation of its sustained release property in vitro.

This study deals with the fabrication of a peripheral nerve scaffold prepared with poly (lactic acid-co-glycolic acid) [PLGA] and acellularized pigskin collagen micro particles and the investigation of its sustained release property in vitro. We took bovine serum albumin [BSA] as model drug to investigate the sustained-release property of the scaffold in vitro. The results showed the scaffold could release BSA steadily with a rate of 6.6 ng/d (r=0.994) or so. In a 1-month test period, the accumulative release ratio of BSA from the scaffold was up to 43%, and the shape of the scaffold was still originally well kept. In addition, the scaffold outcome non-immunogenicity, good cell adhesion and biodegradability. The results indicated a scaffold constructed by this technique would be a potential implanting support with prolonged sustained release function, such as for the use of nerve scaffold.

Characteristics of PLGA-gelatin complex as potential artificial nerve scaffold.

The segmentation lesion of peripheral nerve will seriously impair the motion and sensation of the patients, and the satisfactory recovery of segmented peripheral nerve by autograft or allograft is still a great challenge posing to the neurosurgery. Apart from autograft for nerve repair, different allograft has been studying. In this study, a scaffold fabricated with polylactic acid-co-glycolic acid (PLGA) copolymer and gelatin was evaluated to be a potential artificial nerve scaffold in vitro. The effect of different mass ratio between PLGA and gelatin upon the characteristics of PLGA-gelatin scaffolds such as microstructure, mechanical property, degradation behavior in PBS, cell adhesion property were investigated. The results showed the homogeneity and mechanical property of the scaffolds became poor with the increase of gelatin, and the rate of max water-uptake and the mass loss of scaffolds increases with the increase of gelatin, and the cells could adhere to the scaffolds. Those indicated the scaffolds fabricated by the PLGA-gelatin complex had excellent biocompatibility, suitable mechanical property and sustained-release characteristics, which would meet the requirements for artificial nerve scaffold.

In vitro characteristics of poly(lactic-co-glycolic acid) microspheres incorporating gelatin particles loading basic fibroblast growth factor.

AIM: To construct a sustained drug release system for basic fibroblast growth factor (bFGF). With this special system, bFGF can be used to repair an injured peripheral nerve, injured spinal cord, or as a carrier for other drugs that need to be released over a long time. METHODS: Microsphere composite was prepared by encapsulating bFGF into gelatin particles with poly(lactic-co-glycolic acid) (PLGA) as its outer-coating. The encapsulation was conducted by a phase separation method. RESULTS: The average diameter of the gelatin particle-PLGA microsphere composite was 5-18 mum, and bFGF-loading efficiency was up to 80.5%. The bFGF releasing experiment indicated that this new composite system could release bFGF continuously and protect bFGF from denaturation. CONCLUSION: A modified approach was successfully employed to develop a biodegradable system for sustained release of the drug of bFGF in vitro.