Surface characteristics of thermally treated titanium surfaces

PURPOSE: The characteristics of oxidized titanium (Ti) surfaces varied according to treatment conditions such as duration time and temperature. Thermal oxidation can change Ti surface characteristics, which affect many cellular responses such as cell adhesion, proliferation, and differentiation. Thus, this study was conducted to evaluate the surface characteristics and cell response of thermally treated Ti surfaces. METHODS: The samples were divided into 4 groups. Control: machined smooth titanium (Ti-S) was untreated. Group I: Ti-S was treated in a furnace at 300degrees C for 30 minutes. Group II: Ti-S was treated at 500degrees C for 30 minutes. Group III: Ti-S was treated at 750degrees C for 30 minutes. A scanning electron microscope, atomic force microscope, and X-ray diffraction were used to assess surface characteristics and chemical composition. The water contact angle and surface energy were measured to assess physical properties. RESULTS: The titanium dioxide (TiO2) thickness increased as the treatment temperature increased. Additional peaks belonging to rutile TiO2 were only found in group III. The contact angle in group III was significantly lower than any of the other groups. The surface energy significantly increased as the treatment temperature increased, especially in group III. In the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, after 24 hours of incubation, the assessment of cell viability showed that the optical density of the control had a higher tendency than any other group, but there was no significant difference. However, the alkaline phosphatase activity increased as the temperature increased, especially in group III. CONCLUSIONS: Consequently, the surface characteristics and biocompatibility increased as the temperature increased. This indicates that surface modification by thermal treatment could be another useful method for medical and dental implants.

Naegleria fowleri Lysate Induces Strong Cytopathic Effects and Pro-inflammatory Cytokine Release in Rat Microglial Cells

Naegleria fowleri, a ubiquitous free-living ameba, causes fatal primary amebic meningoencephalitis in humans. N. fowleri trophozoites are known to induce cytopathic changes upon contact with microglial cells, including necrotic and apoptotic cell death and pro-inflammatory cytokine release. In this study, we treated rat microglial cells with amebic lysate to probe contact-independent mechanisms for cytotoxicity, determining through a combination of light microscopy and scanning and transmission electron microscopy whether N. fowleri lysate could effect on both necrosis and apoptosis on microglia in a time- as well as dose-dependent fashion. A 51Cr release assay demonstrated pronounced lysate induction of cytotoxicity (71.5%) toward microglial cells by 24 hr after its addition to cultures. In an assay of pro-inflammatory cytokine release, microglial cells treated with N. fowleri lysate produced TNF-alpha, IL-6, and IL-1beta, though generation of the former 2 cytokines was reduced with time, and that of the last increased throughout the experimental period. In summary, N. fowleri lysate exerted strong cytopathic effects on microglial cells, and elicited pro-inflammatory cytokine release as a primary immune response.

Causes of Precocious Puberty : Multicenter Study in Honam Area / 대한소아내분비학회지

PURPOSE:We analysed the spectrum of diagnoses made in a consecutive group of children referred for signs of precocious puberty and evaluated the clinical and endocrinologic characteristics. METHODS:Retrospective analysis of 375 children (365 girls and 10 boys) referred for evaluation of signs of precocious puberty between January 2003 and May 2007 was done. Results:The conditions causing precocious puberty were early puberty (36.3%), true precocious puberty (30.4%), premature thelarche (29.1%), pseudo-precocious puberty (3.7%), and premature pubarche (0.5%). Among girls, there were differences in the age of onset of puberty (premature thelarche, 5.4+/-2.6 years vs. true precocious puberty, 6.9+/-1.1 years vs. early puberty, 8.6+/-0.5 years). True precocious puberty girls showed higher height SDS (standard deviation score), weight SDS, BMI (body mass index) percentile, basal FSH (follicle stimulating hormone), LH (luteinizing hormone) and estradiol, more accelerated growth velocity and bone age than those with premature thelarche. True precocious puberty patients showed higher height SDS, weight SDS, and more bone age advancement when compared to those with early puberty. Later onset (>2 years) premature thelarche appeared in 89 girls (81.7% of premature thelarche) at 6.4+/-1.6 years, and among 42 patients followed-up, 8 girls developed true precocious puberty later. CONCLUSION:Common conditions causing precocious puberty are early puberty, true precocious puberty, and premature thelarche. Although premature thelarche may be regarded as a benign condition, true precocious puberty can develop in some patients, so careful follow-up will be needed.

Clinical Spectrum of Norovirus Gastroenteritis Compared to Rotavirus Gastroenteritis at a Single Center in Gwanju, Korea during 2005-2006; Compared to Rotaviral Gastroenteritis / 소아감염

PURPOSE:We evaluated the clinical features of Norovirus gastroenteritis compared with Rotavirus gastroenteritis in hospitalized children. METHOD:We detected causative agents in 3,261 samples of children hospitalized with gastroenteritis symptoms at a single center of pediatrics between 2005 and 2006. Among 266 and 303 samples which tested positive for Norovirus and Rotavirus, we selected 73 and 182 samples of children with relatively pure gastroenteritis symptoms and retrospectively analyzed the corresponding medical records. RESULTS:The male-to-female ratio of the Norovirus (+) and Rotavirus (+) groupswas 1.43:1 and 1.56:1 both groups were predominantly in males. The mean age of the Norovirus (+) and Rotavirus (+) groups was 36.7 and 24.4 months, respectively the children in the former group were older than the children in the latter group. The incidence in the Norovirus (+) group was more concentrated in the winter. The symptoms in the Norovirus (+), in decreasing order, included vomiting, diarrhea, and fever. The duration of vomiting, diarrhea, and fever was 2.1, 1.2, and 1.2 days. The maximum number of episodes of vomiting and diarrhea per day was 3.5 and 4.5, respectively. The severity score was 10.16. The symptoms inthe Rotavirus (+) group, in decreasing order, included diarrhea, vomiting, and fever. The duration of diarrhea, vomiting, and fever was 2.2, 4.3, and 2.2 days, respectively. The maximum number of episodes of vomiting and diarrhea per day was 3.3 and 6.5, respectively. The severity score was 11.9. The severity in the Norovirus (+) group was somewhat lower than the Rotavirus (+) group. The younger the child, the more severe the symptoms in the Norovirus (+) group. There was no difference between mono-and co-infection in severity and between the two groups regarding the hematologic findings. CONCLUSION:Based on the findings reported herein, additional studies about prophylaxis, as well as the epidemiology and clinical features of pediatric Norovirus gastroenteritis, are required.