AIM: A new type of unsaturated poly (ester-amide) viz maleic anhydride-phthalic anhydride-propylene glycol-neopentylene glycol-hexane diamine copolymer was prepared by melt polycondensation and characterized.METHODS: To use it as biodegradable bone fixation polymer materials, the flexural strength of unsaturated poly (ester-amide) prepared under different heat treatment conditions was measured after depth cross-linking. The degradation and hydrolysis of the polymer were investigated in phosphate buffer (0.1 mol/L, pH7.4) at 37 ℃ and in 0.1 mol/L NaOH standard solution at room temperature.RESULTS: The results obtained indicate that increasing heat treatment time or temperature can dramatically increase the flexural strength of cross-linked unsaturated poly (ester-amide). The maximum flexural strength of the cross-linked polymer containing 50 wt% of cross-linker was 123 MPa. After degradation 3 months, the flexural strength of the cross-linked polymer that contained 50 wt% of cross-linker and was heated at 195 ℃ for 18 hours could maintain as high as 114.3 MPa.Heat treatment conditions and cross-linker content play an important role to control the mass loss of the cross-linked polymer during the hydrolysis. The polymer exhibits bulk erosion property.CONCLUSION: The preliminary results obtained suggested that the copolymer might be used as bone internal fixation material.

Objective To study the changes in interleukin-32 (IL-32) in rats with Klebsiella bacillus pneumonia and approach its significance. Methods Seventy-two Sprague-Dawley(SD)rats were divide into control group,model group and experimental group by the method of random digits table,then the experimental group was subdivided into 4 hours and 1,3 and 5 days experimental subgroups(each n=6). The rat model of Klebsiella bacillus pneumonia was established by injection of 0.3 mL Klebsiella bacterial suspension into the trachea. Before the establishment of the model in the experimental group,IL-32 inhibitory agent,protease activated receptor-2(PAR2) was injected into the abdominal cavity. After model establishment,at different time points,blood was collected via tail vein to observe the changes in serum levels of IL-32,tumor necrosis factor-α(TNF-α),IL-6 and IL-8 in all the groups. The lungs were removed and stained with hematoxylin-eosin(HE)method to investigate the histopathological changes of the lung tissues under the light microscope. Results Compared to the control group, with the prolongation of time the levels of IL-32,TNF-α,IL-8 and IL-6 were increased gradually in the model group,and reached their peaks at 3 days〔IL-32(ng/L):84.40±28.24 vs. 18.57±3.86,t=5.544,P=0.002;TNF-α(ng/L):79.27±14.64 vs. 17.82±3.86, t=9.994, P=0.000;IL-8(ng/L):55.85±10.90 vs. 16.66±3.76,t=8.544, P=0.000;IL-6(ng/L):56.65±2.57 vs. 28.48±2.11,t=19.693,P=0.000〕;PAR2 could inhibit above indexes significantly,there was statistical difference at 3 days compared with the model group〔IL-32(ng/L):54.13±6.68 vs. 84.40±28.24,t=2.560,P=0.046;TNF-α(ng/L):49.12±3.56 vs. 79.27±14.64,t=4.901,P=0.003;IL-8 (ng/L):22.95±2.52 vs. 55.85±10.90,t=7.204,P=0.000;IL-6(ng/L):36.49±2.63 vs. 56.65±2.57,t=13.443, P=0.000〕. Under the light microscope,the inflammatory changes in the lung tissue in experimental group were milder than those in the model group. Conclusion As a pro-inflammatory cytokine,IL-32 can induce the production of TNF-α,IL-6 and IL-8,and the inhibition of IL-32 production may play a role in suppression of the development of Klebsiella bacillus pneumonia.

Drug slow release in osteomyelitis treatment is an important biomedical problem, to prepare the high effect drug sustained-release bead is the sticking point. A sustained-release bead system consisting of gentamicin sulfate in biodegradable poly(dimer acid-tetradecandioic acid) copolymer [P(DA-TA), WDA: WTA= 50: 50] is prepared by melt casting which may be useful in osteomyelitis treatment. The stability at room temperature and the in vitro release profile in distilling water, in 0.9% saline buffer and in 0.1 mol/LpH7.4 PBS at 37 degrees C of the bead are determined, the drug release behavior in vitro follows the first order release kinetics and Peppas release kinetics equation. In vitro bacteriostatic activity studies demonstrated that the beads possessed desired bacteriostatic activity and lasted for 50 days for Staphylococcus aureus and Escherichia coli, which are common bacteria for infections in bone. All the above suggest that the biodegradable sustained-release beads may be a new treatment device for osteomyelitis treatment.
Delayed-Action Preparations ; chemical synthesis ; pharmacology ; Dicarboxylic Acids ; administration & dosage ; chemical synthesis ; Drug Carriers ; Escherichia coli ; drug effects ; Gentamicins ; administration & dosage ; pharmacology ; Humans ; Microbial Sensitivity Tests ; Osteomyelitis ; drug therapy ; Polyanhydrides ; administration & dosage ; chemical synthesis ; Polymers ; administration & dosage ; chemical synthesis ; Staphylococcus aureus ; drug effects