Development of bioactive zirconium–tin alloy by combination of micropores formation and apatite nuclei deposition

In previous studies, Zr gained apatite‐forming ability by various methods; however, it took more than 7 days in simulated body fluid (SBF) to gain apatite‐forming ability. In this study, the authors developed the method to achieve apatite‐forming ability in Zr alloy within 1 day in SBF by a combination with apatite nuclei that promote apatite formation in SBF. First, Zr–Sn alloy was soaked in concentrated sulphuric acid, and pores in micro‐level were formed on the surface of Zr–Sn alloy. To attain apatite forming ability in Zr–Sn alloy, second, apatite nuclei were formed in the micropores. To evaluate apatite‐forming ability, thus‐obtained Zr–Sn alloy with apatite nuclei was soaked in SBF; hydroxyapatite formation was observed on the whole surface of the Zr–Sn alloy plates. From this result, it was clarified that higher apatite‐forming ability was attained on the apatite nuclei‐treated Zr–Sn alloy with micropores in comparison with that without micropores. When adhesive strength of formed hydroxyapatite film with respect to Zr–Sn alloy plates was measured, high‐adhesive strength of the formed apatite film was attained by forming micropores and subsequently precipitating apatite nuclei in the fabrication process because of an interlocking effect caused by hydroxyapatite formed in the micropores.Inspec keywords: precipitation, zirconium alloys, calcium compounds, bioceramics, tin alloys, adhesion, thin filmsOther keywords: apatite forming ability, micropore formation, hydroxyapatite film, bioactive zirconium‐tin alloy, apatite nuclei‐treated zirconium‐tin alloy, zirconium‐tin alloy plates, simulated body fluid, concentrated sulphuric acid, hydroxyapatite formation, adhesive strength, precipitating apatite nuclei, time 1.0 d, ZrSn, Ca₁₀ (PO₄)₆ (OH)₂      

Impartation of apatite‐forming ability to chitosan nanofibres by using apatite nuclei

Chitosan nanofibre–apatite nuclei composites obtained by mixing apatite nuclei which possess high apatite‐forming ability with chitosan nanofibre have been expected to be novel bone restorative materials with suitable properties such as light weight, low coefficient of thermal expansion, high mechanical strength, biocompatibility and bioactivity. In this study, the authors prepared three types of apatite nuclei by changing the reaction time aimed to optimise their crystallinity and fabricated their composites with chitosan nanofibre. In order to evaluate the bioactivity in vitro, the authors tested apatite‐forming ability in simulated body fluid. As a result, the materials showed enough apatite‐forming ability in a short time by mixing chitosan nanofibre and apatite nuclei with extremely low crystallinity and their high reactivity in simulated body fluid.Inspec keywords: calcium compounds, nanofibres, bioceramics, bone, polymer fibres, nanocomposites, filled polymers, nanomedicine, nanofabricationOther keywords: apatite‐forming ability, chitosan nanofibre‐apatite nuclei composites, bone restorative materials, reaction time, crystallinity, in vitro bioactivity, simulated body fluid, Ca₁₀ (PO₄)₆ (OH)₂      

Resting respiratory sinus arrhythmia is associated with tonic positive emotionality.

Resting respiratory sinus arrhythmia (RSAREST) indexes important aspects of individual differences in emotionality. In the present investigation, the authors address whether RSAREST is associated with tonic positive or negative emotionality, and whether RSAREST relates to phasic emotional responding to discrete positive emotion-eliciting stimuli. Across an 8-month, multiassessment study of first-year university students (n = 80), individual differences in RSAREST were associated with positive but not negative tonic emotionality, assessed at the level of personality traits, long-term moods, the disposition toward optimism, and baseline reports of current emotional states. RSAREST was not related to increased positive emotion, or stimulus-specific emotion, in response to compassion-, awe-, or pride-inducing stimuli. These findings suggest that resting RSA indexes aspects of a person's tonic positive emotionality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improvement of hydroxyapatite formation ability of titanium‐based alloys by combination of acid etching and apatite nuclei precipitation

The authors aimed to improve hydroxyapatite formation ability of Ti6Al4V, Ti‐15Mo‐5Zr‐3Al alloy, Ti‐12Ta‐9Nb‐6Zr‐3V‐O alloy (Gummetal®) and commercially pure Ti (cpTi) mesh by a combination of acid etching and apatite nuclei precipitation. Surfaces of specimens were etched with H₂ SO₄ for pores formation on the specimens. Thus‐etched specimens were soaked in an alkalinised simulated body fluid (SBF), which was adjusted at higher pH than that of conventional SBF and this solution was subsequently heated. By this treatment, apatite nuclei were precipitated in the pores of the specimens. By a soak in the conventional SBF to check hydroxyapatite formation ability, hydroxyapatite was covered the entire surfaces of the specimens within 1 day and high hydroxyapatite formation ability was successfully shown. The adhesion strength of the hydroxyapatite film formed in the above SBF test showed larger value as increasing the surface roughness of the specimens by adjusting the above acid etching condition depending on the kinds of Ti‐based alloys. This is because the adhesion of the hydroxyapatite film occurred by the mechanical interlocking effect. In addition, this method showed shape selectivity of the materials because similar hydroxyapatite formation ability could be introduced to the cpTi mesh.Inspec keywords: tantalum alloys, precipitation, adhesion, niobium alloys, zirconium alloys, aluminium alloys, bioceramics, titanium alloys, surface roughness, etching, vanadium alloys, calcium compounds, molybdenum alloys, thin films, porosityOther keywords: pores formation, hydroxyapatite film, acid etching condition, Ti‐based alloys, hydroxyapatite formation ability, apatite nuclei precipitation, alkalinised simulated body fluid, adhesion strength, surface roughness, mechanical interlocking effect, TiAlV, Ti‐Mo‐Zr‐Al, Ti‐Ta‐Nb‐Zr‐V‐O, Ca₁₀ (PO₄)₆ (OH)₂ , Ti     

Tranilast, an anti-allergic drug, possesses antagonistic potency to angiotensin II

OBJECTIVE: Because of the relationship between childhood behavior disorders and adult substance abuse, we hypothesized that substance abusing adult bipolars were more likely to have had behavior disorders as children than nonabusing bipolar adults. METHODS: Conduct disorder (CD) symptoms in 132 bipolar adults were compared by age and presence of comorbid substance use problems using data from the Epidemiologic Catchment Area study. RESULTS: Rates of CD were higher in bipolar subjects under age 30 (32.6%) versus those over (16.3% P<0.05). Young BPs with substance use problems (SUBST) had CD rates three times those without SUBST (52% vs. 14.8%) (P < 0.01). Young subjects without mania or SUBST had CD rates of 7.75%. CONCLUSION: Substance abuse in bipolar adults may be more related to childhood conduct disorder than uncomplicated bipolar disorder.     

A novel steroid inhibitor for a rat 20alpha-hydroxysteroid dehydrogenase isozyme

20alpha-Hydroxysteroid dehydrogenase (20alpha-HSD, E.C.1.1.1.149) in rat luteal tissue, which catalyzes conversion of progesterone to a biologically inactive steroid, 20alpha-hydroxypregn-4-ene-3-one (20alpha-OHP), suppresses progesterone secretion into the circulation. An increase in 20alpha-HSD activity in luteal tissue in rats is a prerequisite for functional corpus luteum regression. This study was undertaken to find a steroid inhibitor for ovarian cytosolic 20alpha-HSD activity among derivatives based on progesterone structure. A derivative designated as STZ26 (D-homo-16-oxa-4-androstene-3,16alpha-dione) was found to inhibit potently 20alpha-HSD activity in cultured luteal cells. Ovarian 20alpha-HSD activity consists of two isoforms (HSD1 and HSD2). Kinetic analyses of STZ26 for HSD1 and HSD2 showed that the compound suppressed only HSD1 activity by competitive inhibition. Pseudopregnant rats were treated with STZ26 from 13 to 19 days after cervical stimulation. Either an elevation of peripheral 20alpha-OHP levels or a concomitant depletion of peripheral progesterone levels at the end of pseudopregnancy was considerably inhibited in treated animals, although not completely. The results showed that STZ26 is a biologically active inhibitor for HSD1 activity in the luteal tissue and suggested that the depletion of progesterone levels toward the end of pseudopregnancy is not solely due to the elevation of HSD1 activity.     

Intra-operative detection of lymph node involvement in carcinoma of the colon

BACKGROUND/AIMS: We studied the accuracy rate of intra-operative lymph node assessment compared with pathological examination to determine whether surgeons could modify the extent of lymphadenectomy during the operation. METHODOLOGY: Intra-operative and pathological lymph node assessments were compared in 360 patients with carcinoma of the colon. RESULTS: A total of 6,431 lymph nodes were examined, mean number per patient was 17.9. The overall accuracy rate of intra-operative diagnosis was 56.1%, sensitivity was 93.2%, and specificity was 41.7%. The accuracy rate of the diagnosis of N1 and N2 was 43.7% and that of N3 and N4 was 78.3% (p=0.001). There was no significant difference in the diagnosis rates in the colonic region. These results indicated that diagnosis in < or = N3 was more accurate than that in > or = N2. There were 5 false-negative cases. All of the false-negative lymph nodes were located adjacent to the colonic wall. CONCLUSIONS: Intra-operative diagnosis of the positivity of < or = N2 lymph nodes was too poor to decide the extent of lymph node dissection of < D2. It is adequate to dissect according to at least the D2 criteria in all cases. If the surgeon observes N3 involvement, he should add the D3 dissection.     

Potent inhibitors of acyl-CoA:cholesterol acyltransferase. 2. Structure-activity relationships of novel N-(2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)amides

Novel N-(2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)amide derivatives 1 were synthesized and tested for their ability to inhibit rabbit small intestinal ACAT (acyl-CoA:cholesterol acyltransferase) and lower serum total cholesterol in cholesterol-fed rats. Among the synthesized compounds, N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl)amide derivatives showed potent ACAT inhibitory activity. The synthesis and structure-activity relationships of these compounds are described. A methyl group at position 6 of the 2,3-dihydrobenzofuran moiety was important for potent ACAT inhibitory activity. In the series of N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl) amides, lipophilicity of the acyl moiety was necessary for the potent ACAT inhibitory activity. The highly lipophilic acid amides N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl)-2,2- dimethyldodecanamide (10) and 6-(4-chlorophenoxy)-N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-y l)-2,2-dimethyloctanamide (50) showed potent activity. Introduction of a dimethylamino group at position 5 of the 2,3-dihydrobenzofuran moiety resulted in highly potent activity. The most potent compound, N-[5-(dimethylamino)-2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl ]-2,2-dimethyldodecanamide (13, TEI-6620), showed highly potent ACAT inhibitory activity (rabbit small intestine IC50 = 0.020 microM, rabbit liver IC50 = 0.009 microM), foam cell formation inhibitory activity (rat peritoneal macrophage IC50 = 0.030 microM), extremely potent serum cholesterol-lowering activity in cholesterol-fed rats (71% at a dose of 0.3 mg/kg/day po), and good bioavailability in fed dogs (Cmax = 2.68 microg/mL at 1 h, 10 mg/kg po).