Elevated PCT at ICU discharge predicts poor prognosis in patients with severe traumatic brain injury: a retrospective cohort study.

PURPOSE: Disease severity and inflammatory response status are closely related to a poor prognosis and must be assessed in patients with severe traumatic brain injury (STBI) before intensive care unit (ICU) discharge. Whether elevated serum procalcitonin (PCT) levels can predict a poor prognosis in STBI patients before ICU discharge is unclear. METHODS: This retrospective observational cohort study enrolled 199 STBI patients who were in the ICU for at least 48 hours and survived after discharge. Based on serum PCT levels at discharge, patients were divided into the high-PCT group (PCT ≥ 0.25 ng/mL) and the low-PCT group (PCT < 0.25 ng/mL). We assessed the relationship between serum PCT levels and a poor prognosis. RESULTS: The high-PCT group had a higher rate of adverse outcomes compared with the low-PCT group. Multivariate logistic regression analysis showed that the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, Sequential Organ Failure Assessment (SOFA) score, white blood cell (WBC) count, C-reactive protein (CRP) level, and PCT level at discharge were significantly associated with adverse outcomes. CONCLUSIONS: Elevated PCT levels at ICU discharge were associated with a poor prognosis in STBI patients. The serum PCT level as a single indicator has limited value for clinical decision-making.

[Raman and FTIR characteristics of otolith of ornamental carp].

Otolith is a typical natural biomineral as functional deposit existing in teleost's ears, which is mainly composed of calcium carbonate and organic matter. There is a pair of lapillus, sagitta and asteriscus in fish's inner ear, respectively. The authors compare the asteriscus and lapillus in cultured ornamental carp using FTIR and Raman. The result shows that the mineral phase in lapillus is aragonite, while the mineral phase in asteriscus is vaterite. The pure aragonite and vaterite existing respectively in otolith are of importance as being used as sample to study aragonite/vaterite biomineralization mechanism. Compared with inorganic induced aragonite and vaterite using FTIR and Raman, the authors found that the spectra of aragonite in lapillus are between those of inorganic induced aragonite and other bio induced aragonite; while the spectra of vaterite in asteriscus are similar to those of other bio induced vaterite. It is possible that unstable vaterite was stabilized through the organic effects in biomineralization process.

[Repair of radius bone defect with the nano-hydroxyapatite/collagen/calcium alginate].

OBJECTIVE: To explore the osteogenic potential of the nano-hydroxyapatite/collagen/calcium alginate composite implanted in animals. METHODS: Eighteen 3-month-old New Zealand white rabbits were adopted to prepare 15 mm segmental defect model at the middle part of radius. Rabbit models were randomly divided into experimental group and blank control group. Nano-hydroxyapatite/collagen/calcium alginate was implanted into the defects of experimental group. Four, 8, and 12 weeks after operation, all specimens were examined by X-ray and histological methods. RESULTS: All the 18 rabbit models entered the final analysis. X-ray showed that osteotylus was seen in the whole defect area in the experimental group 12 weeks after operation, during which osteogenesis was more obvious than in weeks 4 and 8 and the bridge grafting of defect area was obviously visible. In the blank control group, osteotylus was only observed at the two ends of the defects, and no osteogenesis was found in the central part of the defect area. Histological examination showed that new osteoid formation was seen in internal porous zone in the experimental group in weeks 4 and 8; in week 12, more woven bone-like tissues were visible and trabecular-like structure was formed. CONCLUSION: The nano-hydroxyapatite/ collagen/calcium alginate has good osteogenic potential.

[Preparation and characterization of a new injectable bone substitute-carrageenan/nano-hydroxyapatite/collagen].

OBJECTIVE: To develop a new injectable biomaterial carrageenan/nano-hydroxyapatite/collagen (nHAC/Carr) for bone surgery and characterize it. METHODS: nHAC/Carr was developed by filling carrageenan with nano-hydroxyapatite/collagen (nHAC) granules. RESULTS: It was found that nHAC/Carr had similar X-ray diffraction patterns with that of nHAC. Fourier transform infrared spectroscopy showed that carrageenan did not change its structure in nHAC/Carr. The rheological behavior of nHAC/Carr was the same as carrageenan. The scanning electron microscopy and porosity analysis showed that nHAC/Carr had porous structure and its porosity was about 90%. CONCLUSION: The biomaterial nHAC/Carr may be used as an injectable bone substitute.

[Nano-hydroxyapatite/collagen composite for bone repair].

OBJECTIVE: To develop nano-hydroxyapatite/collagen (NHAC) composite and test its ability in bone repairing. METHODS: NHAC composite was developed by biomimetic method. RESULTS: The composite showed some features of natural bone in both composition and microstructure. The minerals could contribute to 50% by weight of the composites in sheet form. The inorganic phase in the composite was carbonate-substituted hydroxyapatite (HA) with low crystallinity and nanometer size. HA precipitates were uniformly distributed on the type I collagen matrix without preferential orientation. The composite exhibited an isotropic mechanical behavior. However, the resistance of the composite to localized pressure could reach the lower limit of that of femur compacta. The tissue response to the NHAC composite implanted in marrow cavity was investigated. Knoop micro-hardness test was performed to compare the mechanical behavior of the composite and bone. At the interface of the implant and marrow tissue, solution-mediated dissolution and macrophage-mediated resorption led to the degradation of the composite, followed by interfacial bone formation by osteoblasts. The process of implant degradation and bone substitution was reminiscent of bone remodeling. CONCLUSION: The composite can be incorporated into bone metabolism instead of being a permanent implant.