Potential of 4 per cent silver fluoride to induce fluorosis in rats: clinical implications

The Health Department in Western Australia uses a 40 per cent silver fluoride (AgF) solution for prevention and treatment of dental caries in children. Analysis of this solution has revealed high fluoride concentrations (75,000-120,000 mg/L), raising concerns of potential toxicity and prompting investigation of clinical protocols utilizing low-strength AgF in an animal model. A single topical application of 4 per cent AgF solution to Sprague-Dawley rats resulted in moderate to severe localized fluorosis in 24 per cent of animals. In a second experiment, caries was induced in rats aged 19 days; six weeks later, between one-four carious molar teeth from each rat were treated with 4 per cent AgF (atraumatic technique). A generalized form of fluorosis developed in the continually growing incisors of less than 10 per cent of animals which had one or two carious teeth treated, and in 70-90 per cent of rats which received AgF to either three or four carious teeth. These results confirm the potential of a 4 per cent AgF solution to induce fluorosis and support previous recommendations that AgF at its empirical concentration of 40 per cent should be withdrawn from clinical use.     

吡哌酸锌软膏经烧伤创面锌吸收的临床研究

目的：对外用吡哌酸锌软膏经烧伤创面锌吸收进行临床研究。方法：对５６例烧伤总面积２０％以上病人随机分２组——外用吡哌酸锌软膏组和磺胺嘧啶银霜剂组,分别于用药前后不同时间点测血清锌并检测本地正常人血清锌作参照值。结果：２组烧伤病人用药前血清锌均为低值。虽吡哌酸锌软膏组用药后血清锌有所升高,但各时间点其峰值未达正常水平,２４ｈ后又回落到用药前的低值。结论：外用吡哌酸锌软膏锌经烧伤创面有一定吸收,但吸收量甚微。     

Assembly of large-area,highly ordered,crack-free inverse opal films

Whereas considerable interest exists in self-assembly of well-ordered, porous “inverse opal” structures for optical, electronic, and (bio)chemical applications, uncontrolled defect formation has limited the scale-up and practicality of such approaches. Here we demonstrate a new method for assembling highly ordered, crack-free inverse opal films over a centimeter scale. Multilayered composite colloidal crystal films have been generated via evaporative deposition of polymeric colloidal spheres suspended within a hydrolyzed silicate sol-gel precursor solution. The coassembly of a sacrificial colloidal template with a matrix material avoids the need for liquid infiltration into the preassembled colloidal crystal and minimizes the associated cracking and inhomogeneities of the resulting inverse opal films. We discuss the underlying mechanisms that may account for the formation of large-area defect-free films, their unique preferential growth along the 〈110〉 direction and unusual fracture behavior. We demonstrate that this coassembly approach allows the fabrication of hierarchical structures not achievable by conventional methods, such as multilayered films and deposition onto patterned or curved surfaces. These robust SiO₂ inverse opals can be transformed into various materials that retain the morphology and order of the original films, as exemplified by the reactive conversion into Si or TiO₂ replicas. We show that colloidal coassembly is available for a range of organometallic sol-gel and polymer matrix precursors, and represents a simple, low-cost, scalable method for generating high-quality, chemically tailorable inverse opal films for a variety of applications.     

非手术综合治疗骨质疏松症合并脊柱压缩性骨折疼痛疗效

目的：观察非手术综合治疗骨质疏松症合并急性老年脊柱压缩性骨折的近远期疗效。方法：60例骨质疏松症合并急性脊柱压缩性骨折患者随机平分为对照组与治疗组，对照组采用腰带固定及口服阿法骨化三醇、仙灵骨葆，治疗组在对照组基础上采取复方亚甲蓝区域阻滞配合银质针治疗，观察两组VAS评分及优良率。结果：治疗后两组患者VAS评分均较治疗前显著降低（P〈0．05），且治疗组均低于对照组（P〈0．05）；1年后随访，治疗组优良率显著高于对照组（P〈0．05）。结论：非手术综合治疗骨质疏松症合并急性老年脊柱压缩性骨折近远期疗效良好。     

Cytotoxicity of aged cadmium-telluride quantum dots to rainbow trout hepatocytes

The purpose of this study was to examine the lethal and sublethal toxicity of cadmium telluride (CdTe) quantum dots (Q-dots) in primary cultures of rainbow trout hepatocytes. Hepatocytes were exposed to concentrations of positively coated and aged (2 months and 2 years) Q-dots for 48 h at 15°C. Post treatment, cellular analysis was done of cell viability, lipid peroxidation (LPO), DNA damage, metallothioneins (MT), labile zinc/cadmium and heat shock proteins (chaperones). Q-dots were found to be toxic to fish hepatocytes at a threshold concentration of 0.1 mg/l. These nanoparticles increased the levels of MT, labile zinc, DNA strand breaks and heat shock proteins of the 70 kDa family. The strongest response was observed with the molecular chaperone of the 70 kDa family, reaching a 7-fold induction in exposed cells. Overall, the assessment of multiple biomarkers in trout hepatocytes exposed to differently ‘aged’ Q-dots suggests that the cytotoxic responses to two-year-old positively coated CdTe Q-dots were largely due to the liberation of Cd²⁺.     

用双夹心斑点免疫金银染色法检测病人血中疟疾循环抗原

应用抗间日疟原虫和抗恶性疟原虫红内期抗原单克隆抗体建立了双夹心斑点免疫金银染色法和双夹心免疫酶斑点法并用于检测间日疟和恶性疟患者血清中循环抗原。共检测20份间日疟血清和15份恶性疟血清,双夹心斑点免疫金银染色法阳性率分别为90％和93％,可检出最低原虫密度为0.0009％;双夹心免疫酶斑点法阳性率分别为85％和87％,可检出最低原虫密度为0。0075％。与包虫病。弓形虫病和乙肝表面抗原阳性血清无交叉反应,检测60份健康献血员血清,两法分别有5％和8％假阳性。初步结果提示双夹心斑点免疫金银染色法检测疟疾循环抗原敏感度较高,若经过适当改进,有可能用于疟疾现场诊断和流行病学调查。     

Exploration of Novel Co-processed Multifunctional Diluent for the Development of Tablet Dosage Form

The aim of this investigation was to develop a novel multifunctional co-processed diluent consisting of microcrystalline cellulose (Avicel PH 102), crospovidone (Polyplasdone XL) and polyethylene glycol 4000. Colloidal silicon dioxide and talc were also incorporated as minor components in the diluent to improve tableting properties. Melt granulation was adopted for preparation of co-processed diluent. Percentage of Avicel PH 102, Polyplasdone XL and polyethylene glycol 4000 were selected as independent variables and disintegration time was chosen as a dependent variable in simplex lattice design. The co-processed diluent was characterised for angle of repose, bulk density, tapped density, Carr''s index, percentage of fines and dilution potential study. Acetaminophen and metformin were used as poorly compressible model drugs for preparation of tablets. The blend of granules of drug and extra-granular co-processed diluent exhibited better flow as compared to the blend of drug granules and physical mixture of diluents blend. The diluent exhibited satisfactory tableting properties. The tablets exhibited fairly rapid drug release. In conclusion, melt granulation is proposed as a method of preparing co-processed diluent. The concept can be used to bypass patents on excipient manufacturing.     

Passive fit of frameworks in titanium and palladium–silver alloy submitted the laser welding

Summary  This study evaluated the precision of fit of implant frameworks cast in titanium (cp Ti) and palladium–silver alloy (Pd-Ag), made by the one-piece cast and laser welding techniques. From a metal matrix with five implants, 20 master casts were obtained, to which replicas of implants were incorporated. On these masters 10 frameworks were made for each type of material (cp Ti and Pd-Ag alloy). Half of these were made by the one-piece cast technique and the other half by the laser welding technique. The implant/prosthesis interface was analysed and measured in the vestibular and lingual regions of the central and distal implants with the help of a measuring microscope. The results indicated that in the central cylinders, the Tukey test ( P  < 0·0005) showed a significant difference in the passive fit between the laser-welded frameworks (34·73 μm) and those one-piece cast frameworks (151·39 μm), and as regards materials, the palladium–silver alloy (66·30 μm) showed better results than the titanium (119·83 μm). In the distal cylinders there was no significant difference between the frameworks cast in titanium and palladium–silver by the one-piece technique. However, after laser welding, there was a significant difference for the frameworks cast in titanium (31·37 μm) and palladium–silver (106·59 μm).     

Semiquantitative analysis of urinary low protein levels using silver dot blot assay.

We designed a semiquantitative analysis of urinary low protein levels using silver dot blot assay. In this method, 3 microl of urine are blotted to one dot onto a cellulose acetate membrane, which is stained by a colloidal silver staining reagent, and the optical density of the silver stained urinary protein is measured at 500 nm using a densitometer. There was a good linearity between 2.5 mg/L and 100 mg/L and a gentle linearity between 100 mg/L and 200 mg/L, and the minimum sensitivity was 2.5 mg/L. This method is suitable for semiquantitative analysis of urinary protein levels less than 300 mg/L, which can not be determined precisely by dipstick.     

The innervation of tandem muscle spindles in the cat neck

Patterns of innervation were examined in tandem muscle spindles teased from silver-stained muscles of the cat neck. Each tandem spindle was composed of two or more encapsulated receptors linked in series by a shared bag2 fiber. In most tandem spindles, two different types of encapsulation were identified according to differences in their intrafusal fiber content. One type, the b1b2c unit, contained typical bag1, bag2, and chain fibers and was structurally similar to single spindles described in other cat muscles. Each b1b2c unit contained a single primary sensory ending and 1-6 secondary endings. Fusimotor innervation was supplied by many axons. Some fusimotor axons ended in trail ramifications on bag2 and chain fibers, others ended in plates on the bag1 or long chain fiber. The other type of tandem encapsulation, the b2c unit, had only bag2 and chain fibers in its intrafusal fiber bundle. The b2c unit was usually supplied by only one sensory axon that ended on the nucleated part of the intrafusal fiber bundle. This single ending had a more variable terminal morphology than the primary ending in b1b2c units. A few b2c units (3/49) were also supplied by a secondary ending. The fusimotor innervation of the b2c unit was relatively simple. A single pole of the b2c unit was usually supplied by only one to three axons, all ending in trail ramifications. No plate endings were found in b2c units. These morphological specializations suggest that b1b2c and b2c units in tandem spindles differ in both their transductive and fusimotor mechanisms. Thus, the tandem spindle is a specialized structure that may provide additional proprioceptive information beyond that available from single muscle spindles.