Repair of coronary artery ostium with a ring-shaped bovine pericardial patch.

As an approach to coronary artery ostial injury in type A aortic dissection and infective endocarditis, we describe a technique of coronary ostial repair using a ring-shaped bovine pericardial patch. The inner and outer rims of the patch were sutured to the involved coronary ostium (to close the ostial tear) and to the aortic wall (to cover the sinus), respectively. Four patients were successfully managed and computed tomographic coronary arteriogram at follow-up showed patent coronary ostia and arteries. The favourable preliminary results imply that this technique is a simple, safe and effective approach to coronary ostial repair in patients with type A aortic dissection or infective endocarditis.

Identification of ceftazidime interaction with bacteria in wastewater treatment by Raman spectroscopic mapping.

Raman spectroscopy yields a fingerprint spectrum and is of great importance in medical and biological sciences as it is non-destructive, non-invasive, and available in the aqueous environment. In this study, Raman spectroscopy and Raman mapping were used to explore the dynamic biochemical processes in screened bacteria under ceftazidime stress. The Raman spectral difference between bacteria with and without antibiotic stress was analyzed by principal component analysis and characteristic peaks were obtained. The results showed that amino acids changed first and lipids were reduced when bacteria were exposed to ceftazidime stress. Furthermore, in Raman mapping, when bacteria were subjected to antibiotic stress, the peak at 1002 cm-1 (phenylalanine) increased, while the peak at 1172 cm-1 (lipids) weakened. This indicates that when bacteria were stimulated by antibiotics, the intracellular lipids decreased and the content of specific amino acids increased. The reduction of intracellular lipids may suggest a change of membrane permeability. The increase of specific amino acids suggests that bacteria resist external stimuli of antibiotics by regulating the activities of related enzymes. This study explored the processes of the action between bacteria and antibiotics by Raman spectroscopy, and provides a foundation for the further study of the dynamics of microbial biochemical processes in the future.

Effect of different molarity cathepsins specific inhibitor E-64 on dentin-resin bonding durability / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate, in vitro, the effect of cathepsins specific inhibitor N-(trans-epoxysuccinyl)-L-leucine 4-guanidinobutylamide(E-64) on dental endogenous cathepsins and to find its most effective molarity to elevate dentin-resin bonding durability.</p><p><b>METHODS</b>Fifty recently extracted human third molars were divided into five groups according to random number table, and treated with different molarity of E-64 as follow: 0, 2.5, 5.0, 10.0 and 20.0 µmol/L. The group 0 µmol/L was control group. Then 20 specimens of dentin-resin composite were fabricated in each group. Half of the specimens were tested after 24 h water storage(37 °C) and the other half were tested after 90 days water storage(37 °C) followed by 3000 cycles'thermocyling(5-55 °C) as aging treatment. Fractured specimens were analyzed using scanning electron microscopy(SEM).</p><p><b>RESULTS</b>After 24 h water storage, no significant differences were found in micro-tensile bond strength(µTBS) of samples between different groups (P > 0.05). However, after ageing treatment, µTBS of the samples in group 2.5, 5.0, 10.0 and 20.0 µmol/L [(18.7 ± 2.7), (20.8 ± 3.4), (18.3 ± 2.8) and (19.1 ± 2.7) MPa] were significantly higher than that in group 0 µmol/L [(15.1 ± 3.0) MPa] (P < 0.05). Only in the group 5.0 µmol/L no significant difference was found between the original and the decreased value of µTBS(P > 0.05), while the µTBS in other groups decreased significantly after aging treatment(P < 0.05). Failure types were almost adhesive and mixed types. Collagens in hybrid layer were less degraded in the groups using E-64 after aging treatment than control group.</p><p><b>CONCLUSIONS</b>E-64 was effective on inhibiting cathepsins activity in dentin, and induced less collagens degradation in smear layer for better dentin-resin bond durability.</p>

[Experimental study of differentiation of canine bone marrow mesenchymal stem cell into fibroblasts in vitro].

OBJECTIVE: To explore the way of stably inducing canine bone marrow mesenchymal stem cells (BMSCs) to differentiate into fibroblasts and myofibroblasts in vitro, and provide seed cells for fabricating tissue engineering heart valves (TEHV). METHODS: Adult canine BMSCs were separated by a gradient centrifugation on Percoll (density 1.073 g/ml), then the cells were incubated in low-glucose Dulbecco Eagle's minimum essential medium (LG-DMEM) with 10% bovine calf serum. Cell phenotype were identified by immunohistochemistry staining. The second and third generation of BMSCs were committedly induced by conditioning culture medium, which were detected by immunohistochemistry staining. The induced-BMSCs were freezed, preserved and resuscitated after 7 d to observe the cell growth, proliferation and function. RESULTS: BMSCs deriving from the bone marrow mononuclear cells separated by a Percoll gradient were positive expression of alpha-smooth muscle antibody, vimentin and negative expression of CD34, laminin. About (50 +/- 3)% induced-BMSCs were positive expression of laminin. Approximately (85 +/- 3)% freezed induced-BMSCs could be resuscitated. And the growth, proliferation and function were well. CONCLUSION: BMSCs could be committedly induced to differentiate into fibroblasts and myofibroblasts in vitro. It is suitable to be the seed cells.

[Effects of modified acellularization process on porcine endogenous retroviruses in porcine aorta valves].

OBJECTIVE: to study the effect of modified acellularization process on porcine endogenous retrovirus (PERV) in porcine aorta valves (PAVs). METHODS: Twenty aortic valves of pig were put into 0.1% trypsin solution, hypotonic and hypertonic TritonX-100, DNAse solution, RNAse solution, and Hanks solution in succession so as to remove the cells. The specimens of PAV were to undergo gross observation and microscopy before and after the acellularization procedure. Fracture test was made. Primers specific for the conservative gag gene of PERV were designed PCR and RT-PCR were used to detect the expression of gag. In addition, 20 samples of native PAV were collected. Peripheral mononuclear cells (PBMCs). Were isolated from 20 samples of porcine peripheral blood. Ten dogs underwent acellularized PAV replacement; 3 months later, samples of the dogs' peripheral blood were collected. Porcine kidney cells of the line PK15 were used as positive controls. RESULTS: Microscopy showed that all the cells were removed from the acellularized PAVs. Histological analysis showed that the major structural components were maintained. There was no significant difference in fracture strength between the native and acellularized PAVs (P > 0.05). PCR and RT-PCR showed a PERV 219 bp DNA fragment, 90%-95% homologous with the published PERV gene, in the genomic DNA of all native PAVs, pig PBMCs, and PK15 cells, but not in the acellularized PAVs and dog PBMCs. CONCLUSION: PERV exists in all native PAVs. The modified acellularization process succeeds in removing all the cell component and PERV in the PAVs, thus preventing cross-species transmission of PERV.