[Risk factors for multiple debridements of the patients with deep incisional surgical site infection after spinal surgery].

OBJECTIVE: To investigate the risk factors that contribute to multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery and advise medical personnel to pay special attention to these risk factors. METHODS: We retrospectively enrolled 84 patients who got deep incisional surgical site infection after spinal surgery from Jan. 2012 to Dec. 2017. The infections occurred within 30 days after the surgery, and the identification met the criteria of deep incisional surgical site infection of Centers of Disease Control (CDC). Early debridement with first stage closure of the wound and a continuous inflow-outflow irrigation system was used, and reasonable antibiotics were chosen according to the bacterial culture results. During the treatment, the vital signs, clinical manifestations, blood test results, drainage fluid colour and bacterial culture results were acquired. If the infection failed to be controlled or relapsed, a second debridement was performed. Of the 84 cases, 60 undergwent single debridement which included 36 male cases and 24 female cases, and the age ranged from 36 to 77 years, with a mean of 57.2 years. Twenty four had multiple debridements (twice in 14 cases, three times in 6 cases, four times in 1 case, five times in 2 cases, six times in 1 cases) which included 17 male cases and 7 female cases, and the age ranged from 21 to 70 years, with a mean of 49.5 years. Risk factors that predispose patients to multiple debridements were identified using univariate analysis. Risk factors with P values less than 0.05 in univariate analysis were included together in a multivariate Logistic regression model using back-forward method. RESULTS: Multiple debridements were performed in 28.6% of all cases. The hospital stay of multiple debridements group was (82.4±46.3) days compared with (40.4±31.5) days in single debridement group (P=0.018). Instrumentation was removed in 6 cases in multiple debridements group and 4 cases in single debridement group (P=0.049). Flap transplantation was performed in 7 cased in multiple debridements group while none in single debridement group (P < 0.001). Diabetes, primary operation duration longer than 3 hours, primary operation blood loss more than 400 mL, bacteriology examination results, distant site infection were significantly different between the two groups in univariate analysis. In multivariate analysis, primary operation duration longer than 3 hours (OR=3.60, 95%CI: 1.12-11.62), diabetes (OR=3.74, 95%CI: 1.06-13.22), methicillin-resistant Staphylococcus aureus (MRSA) infected (OR=16.87, 95%CI: 2.59-109.73) were the most important risk factors related to multiple debridements in the patients with deep incisional surgical site infection after spinal surgery. CONCLUSION: Diabetes, primary operation duration more than 3 hours, MRSA infected are independent risk factors for multiple debridements in patients suffering from deep incisional surgical site infection after spinal surgery. Special caution and prophylaxis interventions are suggested for these factors.

Crystal structure of a DinB lesion bypass DNA polymerase catalytic fragment reveals a classic polymerase catalytic domain.

The UmuC/DinB family of bypass polymerases is responsible for translesion DNA synthesis and includes the human polymerases eta, iota, and kappa. We determined the 2.3 A resolution crystal structure of a catalytic fragment of the DinB homolog (Dbh) polymerase from Sulfolobus solfataricus and show that it is nonprocessive and can bypass an abasic site. The structure of the catalytic domain is nearly identical to those of most other polymerase families. Homology modeling suggests that there is minimal contact between protein and DNA, that the nascent base pair binding pocket is quite accessible, and that the enzyme is already in a closed conformation characteristic of ternary polymerase complexes. These observations afford insights into the sources of low fidelity and low processivity of the UmuC/DinB polymerases.

Calcium phosphate formation induced on silica in bamboo.

The effect of in vitro induction of calcium phosphate on bamboo surfaces is reported for the first time. Bamboo is studied for biomaterial application due to its elasticity modulus being closer to human bone than other biomaterials. Following an earlier study of cytotoxicity and precipitation of apatite on ground tissue and vascular bundles of bamboo, the composition and function of the minerals in bamboo, especially silica, are considered in the present work. It is found that in both outer and inner surfaces of bamboo culm, there exists some silica. Bamboo elicits an inert response when soaked directly in calcification solution. After the rind of bamboo is treated with sodium hydroxide solution, the silica underneath can induce precipitation of calcium phosphate in an ambient environment. Furthermore, by subsequent grafting with polyethylene glycol (PEG 1000), calcium phosphate induction of bamboo rind can be improved, depending on the concentration of NaOH solution and treatment time. Heat treatment of bamboo can remove the organic materials around the minerals in bamboo, allowing the calcification behaviour of the silica-containing inorganic phase of bamboo in aqueous solution to be studied.

In vitro calcium phosphate formation on a natural composite material, bamboo.

A natural self-reinforced composite material, bamboo, is studied for the first time as a biomedical material. Its anatomical structure was investigated and its mechanical properties were measured and compared with those of some common bone-bonding or bone-repairing biomaterials. It is found that, among all kinds of biomaterials, bamboo has the closest modulus of elasticity to human long bone. The cytotoxicity of bamboo was tested using the agar overlay method before and after heat or chemical treatments. The results reveal that ethanol, methanol and toluene can remove toxic leachable components from bamboo to some extent through extraction. After grafting a polymer whose molecule includes poly(ethylene glycol), alpha,omega-di(aminopropyl)poly(ethylene glycol) 800 on bamboo, bamboo has the ability to form a calcium phosphate coating after being immersed in calcification solution (simulated body fluid and accelerated calcification solution). The characteristics and the morphology of the mineral formed on bamboo were studied by infrared spectroscopy and scanning electron microscopy.

[Diagnosis and treatment of cysticercosis of cerebral ventricles].

31 patients with cysticercosis of cerebral ventricles verified by operation or pathological investigation were reported. All patients were between 7 and 64 years of age and 14 were females. All had a single cyst. Since 29 patients (94%) were without a history of intestinal taeniasis, it was proposed that most patients of cysticercosis of cerebral ventricles were caused by hetero-infection and the entrance of Cysticercus into brain ventricle was through choroid plexus along the cerebrospinal fluid. This is probably the reason why it occurs mostly in the 4th ventricle. The clinical manifestation of cysticercosis of cerebral ventricles were paroxysmal headache and vomiting caused by increased intracranial pressure. Ventriculography and CT scanning have considerable diagnostic value. Removal of Cysticercus by surgical operation is successful (Figs. 1-8).