Search

Low‐crystallinity hydroxyapatite (HAP) foam is an ideal material for bone substitutes and scaffolds for bone tissue regeneration, because its interconnected pores provide the space for cell growth and tissue penetration, and its composition induces excellent tissue response and good osteoconductivity. In this study, the feasibility of low‐crystallinity HAP foam fabrication was evaluated based on the phase transformation reaction or the so‐called dissolution‐reprecipitation reaction of α‐tricalcium phosphate (α‐TCP) foam granules. When α‐TCP foam granules were placed in water at 37°C for 1 day, no reaction was observed. However, α‐TCP foam granules set to form low‐crystallinity HAP by treating it hydrothermally at 200°C. The network of fully interconnected pores was retained, and porosity was as high as 82%. Pore size ranged from 50 to 300 μm with an average pore size of 160 μm. Compressive strength was 207 kPa. Although no setting reaction was observed at 37°C, the setting reaction caused by the hydrothermal treatment of α‐TCP foam granules allowed the fabrication of any shape of low‐crystallinity HAP. Therefore, this method may be useful for the fabrication of bone substitutes and scaffolds in bone tissue regeneration. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009 [ABSTRACT FROM AUTHOR]

Objective: Intellectual function declines in about 30% of children with moyamoya disease (MMD). Memory function underpins higher order brain function, but the relationship between intellectual function and memory in pediatric MMD patients has not been well studied. This study aimed to investigate correlations between scores on the Wechsler Intelligence Scale for Children (WISC) and the Benton Visual Retention Test (BVRT), a visual memory test that can be administered to children, in children with MMD. Relationships between intellectual function or memory and regional cerebral blood flow (rCBF) have also not been well clarified in pediatric MMD patients. The authors also investigated associations between WISC or BVRT scores and rCBF in various brain regions., Methods: WISC and BVRT scores and rCBF were assessed in 17 children with ischemic-onset MMD before revascularization. Single-photon emission CT with 123I-iodoamphetamine was used to measure rCBF. Relationships between WISC and BVRT scores were evaluated using Spearman's correlation coefficient and multivariate linear regression analysis. Cutoff values were identified for BVRT scores. Sensitivity and specificity were calculated to predict full-scale intelligence quotient (FSIQ) > 85 or ≤ 85. Associations between rCBF and WISC or BVRT scores were evaluated using linear regression analysis., Results: BVRT scores were significantly correlated with FSIQ and scores on the Working Memory Index (WMI), Processing Speed Index, and Verbal Comprehension Index (VCI)/Verbal Intelligence Quotient (VIQ) of WISC. Multivariate linear regression revealed that number correct score and number of errors score of BVRT were associated with FSIQ. As cutoff values, a number correct score of 5 and a number of errors score of 8 offered the most reliable predictors of FSIQ > 85 and ≤ 85, respectively. FSIQ correlated positively with rCBF in the right and left hemispheres, right and left ganglia, right and left thalamus, right and left cerebellum, right middle cerebral artery (MCA) territory, pons, and vermis. WMI score was positively associated with rCBF in the right hemisphere, right anterior cerebral artery territory, right MCA territory, right basal ganglia, right and left thalamus, right and left cerebellum, pons, and vermis., Conclusions: BVRT score correlated well with WISC index scores, suggesting that BVRT may be helpful in screening for intellectual impairments in children with MMD. In the MCA territory, basal ganglia, thalamus, cerebellum, pons, and vermis, rCBF associated well with WISC index scores, suggesting that reduced rCBF in relevant brain regions may influence intellectual function.

Introduction: Many studies describe aneurysms measuring ≤3mm as "very small" or "tiny, " with a risk of intraoperative rupture higher than that of most cerebral aneurysms. We evaluated the results of endovascular coil embolization for very small aneurysms with diameter ≤3mm., Material and Methods: The same interventional neurosurgeon performed coil embolization for 14 tiny aneurysms in 14 patients(8male and 6 females)at our institution between May 2015 and June 2017. Patient age range was 42-88 years(average 65.6 years). Five aneurysms had ruptured and 9 were unruptured. Of the 9 unruptured aneurysms, 3 were associated with a previous ruptured aneurysm. We assessed the procedural complications, type of microcatheter and coils used, total number and length of coils, and angiographic results immediately after the procedure., Results: In 14 aneurysm cases, 8 used only 1 pre-shaped microcatheter, 4 used 2, and 2 used 3;cases using multiple microcatheters added final shaping. Only one case used a helical first coil and the remaining 13 cases used a 3-dimensional coil. The number of coils used was 1 in 3 cases, 2 in 7 cases, 3 in 2 cases, and 4 in 2 cases. The total length of coils inserted was <5 cm in 5 cases, 5-10 cm in 5 cases, and >10 cm in 4 cases. The total length of coils used was <10cm in 70% of cases. Immediately after coil embolization, complete occlusion and a neck remnant were achieved in 11 and 3 cases, respectively. Ballooning was induced by intentionally introducing a balloon-assist technique during surgery in 7 cases, and the balloon was actually inflated in 4 cases. Complications were seen in 2 ruptured cases;1 had an intraoperative rupture, the other had parent artery occlusion, and both patients recovered., Conclusion: Coil embolization for tiny aneurysms can be performed comparatively safely by understanding the pitfalls and by using appropriate procedures and tools. Placing the catheter tip at the aneurysm neck is the first step and endovascular treatment is usually performed with ≤3 coils measuring ≤10 cm in total length. Complete embolization should be attempted, but even incomplete embolization is acceptable. More delicate coil embolization is required.

Low-crystallinity hydroxyapatite (HAP) foam is an ideal material for bone substitutes and scaffolds for bone tissue regeneration, because its interconnected pores provide the space for cell growth and tissue penetration, and its composition induces excellent tissue response and good osteoconductivity. In this study, the feasibility of low-crystallinity HAP foam fabrication was evaluated based on the phase transformation reaction or the so-called dissolution-reprecipitation reaction of alpha-tricalcium phosphate (alpha-TCP) foam granules. When alpha-TCP foam granules were placed in water at 37 degrees C for 1 day, no reaction was observed. However, alpha-TCP foam granules set to form low-crystallinity HAP by treating it hydrothermally at 200 degrees C. The network of fully interconnected pores was retained, and porosity was as high as 82%. Pore size ranged from 50 to 300 mum with an average pore size of 160 mum. Compressive strength was 207 kPa. Although no setting reaction was observed at 37 degrees C, the setting reaction caused by the hydrothermal treatment of alpha-TCP foam granules allowed the fabrication of any shape of low-crystallinity HAP. Therefore, this method may be useful for the fabrication of bone substitutes and scaffolds in bone tissue regeneration., ((c) 2008 Wiley Periodicals, Inc.)