Effects of surface charge and palladium on hepatic and kidney injury induced by polystyrene nanoparticles co-administered to mice with paraquat and cisplatin

Recently, with the advancement of nanotechnology, various nanoparticles have been developed and used in fields such as electronics, cosmetics, and foods. However, the toxicity of nanoparticles has yet to be fully investigated. In particular, the interactions between nanoparticles and therapeutic drugs require further study. We previously reported that unmodified polystyrene nanoparticles with a particle size of 50 nm (NPP50) co-administered with paraquat (PQ) or cisplatin (CDDP) induce hepatic and kidney injury. Here, we determined if NPP50 modified with the amino group (NPP50-NH2), carboxyl group (NPP50-COOH), or palladium (Pd-NPP50) caused liver or kidney injury when co-administered with PQ or CDDP. The results showed that when NPP50-NH2, NPP50-COOH, or Pd-NPP50 was administered alone via the mouse tail vein, serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and blood urea nitrogen (BUN) did not increase or cause injury. When NPP50, NPP50-NH2, NPP50-COOH, or Pd-NPP50 was co-administered with PQ, serum levels of ALT and AST increased in the NPP50 group but did not increase in the NPP50-NH2, NPP50-COOH, or Pd-NPP50 groups. When NPP50-NH2, NPP50-COOH, or Pd-NPP50 was co-administered with CDDP, ALT, AST, and BUN values did not increase. These data suggest that injury due to the interaction of polystyrene nanoparticles with CDDP or PQ can be suppressed by changes in the surface charge of nanoparticles or by Pd modification.

Hepatotoxicity, nephrotoxicity, and drug/chemical interaction toxicity of platinum nanoparticles in mice

Nanomaterials are frequently used in microelectronics, cosmetics, and sunscreens. Platinum reagents are commonly used in disease diagnosis, cosmetics, and the food industry. Although research into the development of nanomaterialbased drug delivery systems has yielded promising results, the toxicity of these materials is not fully understood. We investigated the toxicity and drug interactions of 1- and 8-nm diameter platinum nanoparticles (nPt1 and nPt8, respectively) in mice. Acute hepato-renal toxicity of intravenously administered platinum nanoparticles was evaluated biochemically and histologically. Dose-dependent increases in serum markers of hepato-renal function (serum aminotransferases and blood urea nitrogen) were observed following administration of nPt1, whereas nPt8 had no effect, even at 20 mg/kg. Moreover, nPt1 induced interleukin (IL)-6 and IL-1β production 3 and 6 hours after administration. The effect of nPts on drug-induced toxicity was evaluated in mice injected intraperitoneally with carbon tetrachloride or cisplatin, with or without intravenous administration of platinum nanoparticles. All treatments in the absence of nanoparticles were non-lethal and resulted in moderate toxicity. However, exacerbated toxicity was observed in mice injected with carbon tetrachloride or cisplatin together with nPt1, but not in mice co-injected with nPt8. We found that nPt1 cause hepato-renal damage, and the effect is enhanced by chemical inducers of hepatotoxicity and nephrotoxicity. This is the first report demonstrating that nPt1 not only are hepatotoxic and nephrotoxic but also exacerbate drug toxicity. These findings will be useful for future nanotechnology and nanoscience research.

The hepatoprotective effect of lycopene on Con A-induced liver injury in mice

Lycopene, the main fat-soluble pigment responsible for the red color of ripe tomatoes, is a symmetrical tetraterpene comprising eight isoprene units. In vitro and in vivo studies have shown that lycopene acts as a potent antioxidant; it is 100 times more effective than vitamin E and 125 times more effective than glutathione as an antioxidant. Here, we divided BALB/c male mice into three equal groups: control, Concanavalin A (Con A), and Con A and lycopene. The control group mice received only vehicle by intraperitoneal injection, the Con A group mice were given Con A, and the Con A and lycopene group mice received Con A and lycopene. The results showed that Con A administration increased histopathological damage, and the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), interleukin (IL)-6, interferon (IFN)-γ and tumor necrosis factor (TNF)-α were increased in serum samples whereas the levels of these compounds were significantly decreased in the Con A and lycopene group compared to the Con A group. Furthermore, we observed that lycopene led to an increase in cell viability and cell growth. The results of this study revealed that lycopene might be a useful hepatoprotective agent for reducing increased proinflammatory cytokine levels, and for increasing cell viability and cell growth.

Angular Momentum of Twisted Radiation from an Electron in Spiral Motion

We theoretically demonstrate for the first time that a single free electron in circular or spiral motion emits twisted photons carrying well-defined orbital angular momentum along the axis of the electron circulation, in adding to spin angular momentum. We show that, when the electron velocity is relativistic, the radiation field contains harmonic components and the photons of lth harmonic carry lℏ total angular momentum for each. This work indicates that twisted photons are naturally emitted by free electrons and are more ubiquitous in laboratories and in nature than ever thought.

Communicating Radiation Risk to the Population of Fukushima

Radiological specialists from Nagasaki University have served on the medical relief team organized at Fukushima Medical University Hospital (Fukushima City) ever since the accident at the Fukushima Dai-ichi nuclear power plant. Furthermore, we have conducted the radiation crisis communication efforts by spreading correct information on the health effects of radiation as 'advisors on radiation health risk control'. Nagasaki University has been assisting the reconstruction efforts of Kawauchi Village in Fukushima Prefecture, which was the first village to declare that residents could safely return to their homes because radiation doses were found to be at comparatively low levels. In April 2013, Nagasaki University and the Kawauchi government office concluded an agreement concerning comprehensive cooperation toward reconstruction of the village. As a result, we established a satellite facility of the university in the village. In conclusion, training of specialists who can take responsibility for long-term risk communication regarding the health effects of radiation as well as crisis communication in the initial phase of the accident is an essential component of all such recovery efforts. Establishment of a training system for such specialists will be very important both for Japan and other countries worldwide.

Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats

Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump.

Damage control interventional radiology (DCIR) in prompt and rapid endovascular strategies in trauma occasions (PRESTO): A new paradigm

This article proposes an innovative concept of interventional radiology for hemodynamically unstable trauma patients. Damage control interventional radiology (DCIR) is an aggressive and time-conscious algorithm that prioritizes saving life of the hemorrhaging patient in extremis which conventional emergency interventional radiology (CEIR) cannot efficiently do. Briefly, DCIR aims to save life while CEIR aims to control bleeding with a constant concern to time-awareness. This article also presents the concept of "Prompt and Rapid Endovascular Strategies in Traumatic Occasions" (PRESTO) that entirely oversees and manages trauma patients from arrival to the trauma bay until initial completion of hemostasis with endovascular techniques. PRESTO's "Start soon and finish sooner" relies on the earlier activation of interventional radiology team but also emphasizes on a rapid completion of hemostasis in which DCIR has been specifically tailored. Both DCIR and PRESTO expand the role of IR and represent a paradigm shift in the realm of trauma care.

Polysaccharide films at an air/liquid and a liquid/silicon interface: effect of the polysaccharide and liquid type on their physical properties

We investigated the effect of the polysaccharide type, the subphase on which the Langmuir monolayers were prepared, and the liquid in which the properties of the transferred monolayers were measured on the physical properties of the polysaccharide films at an air/aqueous interface and at a silicon substrate, and the forces and friction of the polysaccharide transferred films when measured in solution against a silica probe. Chitosan was modified with a silane coupling agent to make chitosan derived compounds with a low and a medium molecular weight. Chitin and the chitosan-derived compounds were used to make Langmuir monolayers at air/water and air/pH 9 buffer interfaces. The monolayers were transferred to silicon substrates via Langmuir-Blodgett deposition, and the chitosan-derived compounds subsequently chemically reacted with the silicon substrates. Atomic force microscope force and friction measurements were made in water and in the pH 9 buffer, where the water and the pH 9 buffer acted as a good and a bad solvent for the polysaccharides, respectively. The polysaccharide type affected the friction of the polysaccharide film, where the physically adsorbed chitin gave the lowest friction. The friction of L-chitosan was higher than that of M-chitosan in water, suggesting that the molecular weight of the polymer affects its lubricating ability. The forces and friction of the polysaccharide films changed when the subphase on which the Langmuir monolayers were formed was changed or when the liquid in which the properties of the films adsorbed at the silicon substrate were measured was changed. The friction increased significantly when the liquid was changed from water to the pH 9 buffer. This increase was explained by the reduced charge of the chitin and chitosan-derived materials due to the pH increase, the screening of the charges by the salts in the buffer, and the possible hardening of the monolayer caused by the adsorption of salts from the buffer.

Photon-induced positron annihilation lifetime spectroscopy using ultrashort laser-Compton-scattered gamma-ray pulses

High-energy ultrashort gamma-ray pulses can be generated via laser Compton scattering with 90° collisions at the UVSOR-II electron storage ring. As an applied study of ultrashort gamma-ray pulses, a new photon-induced positron annihilation lifetime spectroscopy approach has been developed. Ultrashort gamma-ray pulses with a maximum energy of 6.6 MeV and pulse width of 2.2 ps created positrons throughout bulk lead via pair production. Annihilation gamma rays were detected by a BaF2 scintillator mounted on a photomultiplier tube. A positron lifetime spectrum was obtained by measuring the time difference between the RF frequency of the electron storage ring and the detection time of the annihilation gamma rays. We calculated the response of the BaF2 scintillator and the time jitter caused by the variation in the total path length of the ultrashort gamma-ray pulses, annihilation gamma rays, and scintillation light using a Monte Carlo simulation code. The positron lifetime for bulk lead was successfully measured.

Implant-retained overdenture following hemiglossectomy: a 10-year clinical case report

A clinical evaluation of an implant-supported overdenture placed in the edentulous mandible after hemiglossectomy is described. The deltopectoral flap covering the mandibular ridge was replaced with a free mucosal graft. Four Brånemark system implants were inserted into the anterior part of the mandible, but one of the four fixtures did not show osseointegration. The superstructure was designed as a spaced round bar-attachment supported by three implants so as to retain the complete overdenture. In addition to the metal clip, a silicone-based soft denture liner material was applied in the female portion of the attachment so as to prevent the attachment from making a clattering noise upon mastication. Although the overdenture required adjustment at regular intervals, the treatment was successful both aesthetically and functionally for up to at least 10 years.

Abrasion resistance of titanium nitride coatings formed on titanium by ion-beam-assisted deposition

To improve the physical properties of the pure titanium surface, thin titanium nitride (TiN) films were deposited by means of ion-beam-assisted deposition. Film structure was confirmed as TiN by X-ray diffraction analysis. Surface hardness and abrasion resistance were significantly improved on TiN-coated specimens. Five combinations of oral hygiene instruments and materials were applied to the specimens as simulations of the oral environment. Treatment with the metal scaler and ultrasonic scaler severely changed the surface features and significantly increased the surface roughness parameters on pure titanium controls, whereas only small scratches and dull undulations were seen on the TiN-coated specimens. Profilometric tracings and scanning electron micrographs demonstrated the improved abrasion resistance of the TiN-coated specimens.

Dot pattern generation technique using molecular dynamics

We have developed a new technique for generating homogeneously distributed irregular dot patterns useful for optical devices and digital halftoning technologies. To introduce irregularity, we use elaborately designed sequences called low-discrepancy sequences instead of pseudorandom numbers. We also use a molecular-dynamics redistribution method to improve the distribution of dots. Our method can produce arbitrary density distributions in accordance with a given design. The generated patterns are free from visible roughness as well as any moiré patterns when superimposed on other regular patterns. We demonstrate that our method effectively improves luminance uniformity and eliminates moiré patterns when used for a backlight unit of a liquid-crystal display.

Surface treatment of dentin with GLUMA and iron compounds for bonding indirect restorations

The purpose of this study was to evaluate five dentin bonding systems simulating indirect restorations. The surface of bovine and human dentin was primed with a glutaraldehyde agent (GLUMA) and placed in a humidor at 37 degrees C for 168 h. In an experimental bonding system (GLUMA/CY/SB), the surfaces were etched with phosphoric acid, primed with cytochrome c, and then bonded to an acrylic rod with a self-curing resin (4-META/MMA-TBB). Specimens using two commercially available bonding systems [All-Bond 2 (AB2) and Super-Bond C & B (10-3/SB)] and two controls with and without GLUMA (GLUMA/10-3/SB and CY/SB) were also prepared. Tensile testing revealed that the bond strengths were influenced by the bonding system, 168 h dentin exposure and their interaction, but not by the tooth origin. AB2 showed the lowest bond strength. With the 10-3/SB system, exposing the dentin to humidity resulted in a decrease in bond strength. After 168 h of exposure, no significant differences were observed between 10-3/SB and CY/SB. The most effective bonding was obtained with the bonding systems of GLUMA/10-3/SB and GLUMA/CY/SB. Improved outcome is expected with these bonding systems when building up abutment teeth with indirect restorations.

Increased vascular endothelial growth factor peptide and gene expression in hypoplastic lung in nitrofen induced congenital diaphragmatic hernia in rats

Persistent pulmonary hypertension (PPH) in congenital diaphragmatic hernia (CDH) lung has been shown to be associated with structural changes in the pulmonary vasculature, including medial and adventitial thickening. Vascular endothelial growth factor (VEGF) is a potent mitogenic and permeability factor targeting predominantly endothelial cells. mRNA encoding VEGF is detected in all fetal tissues and is most abundant in fetal lung, kidney, and liver. Recently, antenatal dexamethasone (Dex) treatment has been shown to prevent pulmonary-artery structural changes in experimentally-produced CDH. The aim of this study was to investigate mRNA and protein levels of VEGF in CDH lung and to determine whether antenatal Dex treatment has any effect on the production of VEGF. A CDH model was induced in pregnant rats following administration of 100 mg nitrofen on days 9.5 of gestation (term=22 days). Dex 0.25 mg/kg was given on day 18.5 and 19.5. Cesarean section was performed on day 21 of gestation. The fetuses were divided into three groups: normal controls (NC, n=8); nitrofen-induced CDH (CDH, n=8); and nitrofen-induced CDH with antenatal Dex treatment (CDH-Dex, n=8). Protein and mRNA were extracted from the whole lung. VEGF protein was measured by ELISA assay and mRNA expression was evaluated by reverse transcription-polymerase chain reaction. Immunohistochemistry using anti-rat VEGF antibody was also performed in each group. VEGF protein as well as mRNA expression were significantly increased in the CDH group compared to the NC group, which was not affected by antenatal Dex treatment. VEGF immunoreactivity in pulmonary vessel walls was increased in the CDH and CDH-Dex groups compared to the NC group. The enhanced VEGF protein and mRNA expression in CDH lung suggests that increased local synthesis of VEGF may be responsible for the structural changes in the pulmonary vasculature in CDH lung. VEGF expression in CDH lung is not downregulated by antenatal Dex treatment.

Effect of disinfectants containing glutaraldehyde on bonding of a tri-n-butylborane initiated resin to dentine

The purpose of this study was to evaluate the effects of disinfectants on the bond strength of resin to dentine. The surface of bovine dentine was exposed to formaldehyde (FA) aqueous solutions, glutaraldehyde (GA) aqueous solutions, 2-hydroxyethyl methacrylate aqueous solutions (HEMA), a commercially available dentine primer (Gluma CPS desensitizer, GLUMA), isotonic sodium chloride solution (IS), and distilled water (DW), and placed in a humidor (HU) at 37 degrees C, or non-stored (baseline). All dentine surfaces were conditioned with a 10% citric acid and 3% ferric chloride solution (10-3 liquid), and then bonded to an acrylic rod with a self-curing adhesive resin (Super-Bond C&B). The mean tensile bond strengths determined 24 h after bonding were compared by analysis of variance (ANOVA) and Fisher's protected LSD test (n=5, P < or = 0.05). The exposure of dentine to IS, DW and HU for both 48 and 168 h resulted in a decrease in bond strength when compared with the baseline. The highest bond strengths after 168 h of exposure were obtained with 5% GA, 10% HEMA, and GLUMA, the values of which were equivalent to baseline and were significantly higher than that of FA. It is concluded that disinfectant pre-treatment with 5% GA or GLUMA stabilizes the bonding of tri-n-butylborane (TBB) initiated luting agent to bovine dentine conditioned with 10-3 liquid.

Adhesive bonding of composite material to cast titanium with varying surface preparations

The purpose of the present study was to evaluate the surface preparation effects of eight metal conditioners and an adhesive system on bonding between a prosthodontic composite material and cast titanium. Eight primers designed for conditioning base metal alloys (Acryl Bond, All-Bond 2 Primer B, Alloy Primer, Cesead II Opaque Primer, Eye Sight Opaque Primer, Metafast Bonding Liner, Metal Primer II, and MR Bond) as well as a surface modification technique (Siloc) were assessed. Disk specimens cast from titanium (T-Alloy H) were either primed with one of the eight primers or treated with the Siloc system, and then bonded with a light-activated composite material (Artglass). Bond durability was evaluated by thermocycling (4 and 60 degrees C, 1 min each, 20, 000 cycles). After thermocycling, two groups either primed with the Cesead II Opaque Primer material or treated with the Siloc system exhibited significantly greater bond strength (20.0 and 19.0 MPa) than the other groups (0.2-12.6 MPa, P < 0.05). These two systems are considered to be useful for improving bonding between the titanium and the composite material tested.

Effect of desensitizers on bond strength of adhesive luting agents to dentin

The current study investigates the influence of three dentin hypersensitivity treating agents (Gluma CPS, MS Coat and Saforide) on bond strength to dentin of two luting agents (Panavia Fluoro Cement and Super-Bond C & B). Sixty bovine dentin substrates were divided into 12 combinations of four treatment conditions (Gluma CPS, MS Coat, Saforide and control) and three adhesive systems (AD Gel sodium hypochlorite + Panavia Fluoro Cement, Panavia Fluoro Cement without AD Gel and Super-Bond C & B). After bonding the treated teeth to steel rods, 24-h tensile bond strengths were determined, and average values (n=5) were compared by analysis of variance (ANOVA). Without application of the desensitizers, bond strengths of the two groups (Super-Bond C & B, 10.2 MPa; AD Gel + Panavia, 11.5 MPa) were comparable, and they were greater than the group bonded with the Panavia material with no AD Gel conditioning (7.1 MPa). Application of the Saforide ammoniated silver fluoride desensitizer reduced bond strength of both the Super-Bond and Panavia luting agents, whereas the MS Coat polymeric agent negatively affected bond strength of the Panavia cement only. The use of the Gluma desensitizer did not affect bond strength of any of the three adhesive systems, and the bond strength of the Panavia cement with the AD Gel conditioning was not reduced by application of any of the three desensitizers. The four combinations of two desensitizers (MS Coat and Gluma CPS) and two adhesive systems (Super-Bond C & B and AD Gel + Panavia) are deemed to be applicable to fixed prosthodontic treatment.

Acclimation to the growth temperature and the high-temperature effects on photosystem II and plasma membranes in a mesophilic cyanobacterium, Synechocystis sp. PCC6803

High-temperature effects on Photosystem II and plasma membranes, temperature dependence of growth, and acclimation to the growth temperature were studied in a mesophilic cyanobacterium, Synechocystis sp. PCC6803. The following results were obtained. (1) Small but distinct temperature acclimation of the PSII reaction center activity was shown for the first time when the activity was measured at inhibitory high temperatures. However, the reaction center activity showed no apparent acclimation when it was measured at growth temperatures after heat stress. (2) Oxygen-evolving activity and the permeability of plasma membranes showed higher resistance to heat when PCC6803 cells were grown at higher temperatures. (3) Acclimation of photosynthesis to the growth temperature seemed to occur so as to maintain photosynthesis activity not at a maximum level but in a certain range at the growth temperatures. (4) Neither sensitivity to high-temperature-induced dissociation of phycobilisomes from the PSII reaction center complexes nor degradation of phycocyanin were altered by changes in the environmental temperature. (5) A close relationship between the viability of cells and the structural changes of plasma membranes (but not the inactivation of photosynthesis) was observed. The denaturation process of PSII complexes and the relationship between the temperature dependence of the growth of Synechocystis PCC6803 cells and that of the photosynthetic activity are also discussed.

Adhesive bonding of titanium nitride-plated stainless steel for magnetic attachments

The purpose of this study was to evaluate adhesive bonding of resin to titanium nitride ion-plated stainless steel in order for magnetic attachments to survive in the oral environment. Two primers, Cesead II Opaque Primer (CPII) and Metal Primer II (MPII), and one bonding agent, Super-Bond C&B (SB), were used. The surfaces of stainless steel disks were ground and then plated with titanium nitride. After the primer and SB resin were applied, a self-curing resin was bonded to the metal surfaces. Shear bond strengths were determined after 24 h of water storage and after 2,000 thermocycles. Titanium nitride ion-plated stainless steel showed bond strength comparable to the non-plated material. After thermocycling, all specimens of the group no primer/no SB were debonded. The bond strengths of groups CPII/no SB, MPII/no SB and no primer/SB were significantly lower bond strengths than groups CPII/SB and MPII/SB. An appropriate combination of primer and bonding agent should be selected when bonding a magnetic attachment to the denture base.

Wear of luting materials with titanium retainer

PURPOSE

The purpose of this study was to investigate the wear resistance of prosthodontic luting materials with a titanium framework by means of an in vitro three-bodied wear-testing device.

MATERIALS AND METHODS

The surfaces of flat cast titanium disks were blasted with 50 microns alumina. Placing a 50 microns masking tape on the plane surface, the disks were bonded with five luting materials. The axial surfaces of the bonded disks were ground flat with 600 grit silicon-carbide paper, and then cyclically loaded (75.6 N, 1.2 Hz) by a chewing simulator for 400,000 cycles. The distance between titanium and cement surfaces was measured in micrometers by means of a profilometer to determine delta wear, and the surface texture was evaluated with a scanning electron microscope.

RESULTS

The delta wear measurement showed that the resistance of Super-Bond Opaque adhesive was significantly higher than Panavia Fluoro adhesive and Fuji I cement after 400,000 wear cycles. No significant differences were detected among Super-Bond Opaque adhesive, Super-Bond adhesive, and All-Bond adhesive. Visually, continuity with the titanium framework was observed when the titanium disks were luted with resin systems.

Properties of opaque resin composite containing coated and silanized titanium dioxide

Titanium dioxide (TiO2) is mainly used as a pigment in opaque resin composites for application to the surface of a metal framework. The hypothesis in this paper is that particles of silica/alumina (SiO2/Al2O3)-coated TiO2 treated with a silane coupling agent could bond effectively with resin monomers of opaque resin composites. Untreated TiO2 was used as the control filler. Compressive and flexural strength specimens were prepared by the heat-curing method, because these bulk specimens could not be made by the typical photo-curing method. The treated composite had significantly higher compressive and flexural strengths than the untreated composite after 6 months' immersion in water. Scanning electron microscopy of the fractured composite surfaces showed an interface failure between TiO2 and resin for the untreated composite and cohesive failure within the resin for the treated composite after 6 months' immersion. The light-activated opaque resin composite containing treated TiO2 exhibited significantly higher bond strength to a noble dental alloy after 5000 thermal cycles than that containing untreated TiO2. Thus, silanized SiO2/Al2O3-coated TiO2 appears to be clinically useful as a filler of opaque resin composites.

Effect of three adhesive primers on the bond strengths of four light-activated opaque resins to noble alloy

The effect of commercial adhesive primers for noble metals on the bond strength of light-activated opaque resin has not been determined. This study evaluated the effect of three adhesive primers on the shear bond strengths of each of the four light-activated opaque resins to silver--palladium--copper--gold (Ag--Pd--Cu--Au) alloy. The adhesive primers Alloy Primer (AP), Metal Primer II (MPII) and Metaltite(MT) were used. Four commercial light-activated opaque resins (Axis (AX), Cesead II (CEII), Dentacolor(DE) and Solidex (SO) were used to bond a light-activated resin-veneered composite to Ag--Pd--Cu--Au alloy. The specimens were stored in water at 37 degrees C for 24 h and then immersed alternatively in water baths at 4 and 60 degrees C for 1 min each for up to 20,000 thermal cycles before shear mode testing at a cross-head speed of 0.5 mm min(-1). All the primers examined improved the shear bond strength between opaque resin and Ag--Pd--Cu--Au alloy compared with non-primed specimens prior to thermal cycling. After 20,000 thermal cycles, the bond strengths of combined use of AP and DE and that of MT and each of AX, CE or DE were significantly greater than any other groups. Significant difference was observed between the bond strengths at thermal cycles 0 and 20,000, with the combined use of MT and DE. With the combination of appropriate adhesive metal primers and light-activated opaque resins, complicated surface preparations of metal frameworks of resin-veneered prostheses that are composed of casting Ag-Pd-Cu-Au alloy may be negligible.

Spinal and supraspinal midazolam potentiates antinociceptive effects of isoflurane

The effects of lumbar intrathecal (i.t.) and intracerebroventricular (i.c.v.) midazolam on nociception during isoflurane anaesthesia were studied in rats using the tail-flick test. Rats received i.t. midazolam 2 and 4 microg or i.c.v. midazolam 4 and 8 microg during 1.1, 1.2 and 1.3% isoflurane or without isoflurane. Neither i.t. nor i.c.v. midazolam alone at doses studied influenced nociceptive responses. 1.1% isoflurane showed a minimum antinociceptive effect which was not influenced by i.t. or i.c.v. midazolam. 1.2 and 1.3% isoflurane produced moderate antinociception which was markedly potentiated by both i.t. and i.c.v. midazolam. The effects of midazolam shown in the present study are different from the reported effects of midazolam on opioid-induced antinociception; where spinally administered midazolam potentiates and supraspinal midazolam inhibits the antinociceptive effects of morphine. The present results suggest that midazolam potentiates isoflurane-induced antinociception at doses where no effect is seen alone.

Participation of transcription elongation factor XSII-K1 in mesoderm-derived tissue development in Xenopus laevis

We isolated a cDNA clone for a novel member of the S-II family of transcription elongation factors from Xenopus laevis. This S-II, named XSII-K1, is assumed to be the Xenopus homologue of mouse SII-K1 that we reported previously (Taira, Y., Kubo, T., and Natori, S. (1998) Genes Cells 3, 289-296). Expression of the XSII-K1 gene was found to be restricted to mesoderm-derived tissues such as liver, kidney, and skeletal muscle. Contrary to the general S-II gene, expression of the XSII-K1 gene was not detected in embryos at stages earlier than 11. The animal cap assay revealed that activin A, but not basic fibroblast growth factor, induced expression of the XSII-K1 gene and that it participated in the expression of mesoderm-specific genes such as Xbra and Xalpha-actin. This is the first demonstration that the regulation at the level of transcription elongation is included in the development of mesoderm-derived tissues.

Bond strength of prosthodontic luting materials to titanium after localized cyclic loading

PURPOSE

To establish an in vitro analysis system to evaluate the effect of cyclic loading on the bond strengths and durability of luting materials bonded to titanium.

MATERIALS AND METHODS

Machine-milled titanium disks were finished with 600 grit silicon-carbide paper and pairs of disks were bonded together using the five different luting materials. A stainless steel stylus was vertically loaded at a center position (Model 1) or at the border (Model 2) of the specimens with a force of 75.6 N at 7500 cycles/hr. When the stylus contacted the specimen surface through the water slurry of poly(methyl methacrylate) beads, it rotated clockwise up to 15 degrees and counter-rotated. Shear bond strengths were determined 1 hr after bonding, after storage in water at room temperature for 24 hr, and after the loading for 100,000 cycles.

RESULTS

The bond strengths of the unfilled adhesive resin and resin-based composite cement (RBC) were significantly higher than those of the glass-ionomer cements. Zinc phosphate cement demonstrated no bonding ability to titanium. After 100,000 cycles, peripheral loading in Model 2 significantly reduced the bond strength of the RBC and glass-ionomer cements, while Model 1 loading did not. The highest and the most durable bonds were obtained with the unfilled adhesive resin in both models.

[Continuous hepatic arterial infusion of 5-fluorouracil with leucovorin for unresectable liver metastases from colorectal cancer]

Twenty-three patients with liver metastases from colorectal cancer were treated by continuous hepatic arterial infusion chemotherapy with 5-FU and Leucovorin. The regimen was that 500 mg/body of 5-FU with 30 mg/body of Leucovorin was administered continuously for 5 days, followed by no medication for 16 days. The effect of this therapy was evaluated and the relationship between this therapy and the overexpression of vascular endothelial growth factor (VEGF) or microvessel density (MVD) was also studied. Complete response was obtained in 4 patients and partial response in 3 patients; the response rate was 32%. The response rate was 60% in patients who underwent more than 7 courses. The response rate was 44% in patients with positive VEGF and 33% in patients with negative VEGF. The response rate was 50% in patients with an MVD of more than 30 and 33% in patients with an MVD of less than 30. The 3-year survival rate for patients who underwent more than 7 courses was 37.5%. This therapy had to be abandoned in 6 patients due to occlusion of the catheter. Skillful maintenance of the catheter is necessary for a high response rate and satisfactory prognosis using this therapy.

[Pre-emptive analgesia with intravenous ketamine reduces postoperative pain in young patients after appendicectomy: a randomized control study]

Thirty-six young patients (12-17 years old) for appendicectomy were randomly allocated to receive ketamine 0.5 mg.kg-1 (K 0.5 group; n = 12), ketamine 1.0 mg.kg-1 (K 1.0 group; n = 12), or lactated Ringer's solution 5 ml (control group; n = 12), which was administered intravenously before incision. After the surgery, all patients received a nonsteroidal anti-inflammatory drug (NSAID) without limitation as requested by the patient. Pain scores at rest and on movement were assessed at 6-10 hr, 24 hr, and 48 hr post-operatively using a visual analogue scale. The frequency at which NSAID was given for postoperative analgesia in the first 48 hr after the surgery was recorded. The patients in the K 0.5 and K 1.0 groups had significantly lower pain scores at rest 6-10 hr postoperatively than the patients in the control group (P < 0.05). Additionally, the patients in the K 1.0 group had a significantly lower pain score on movement 6-10 and 48 hr postoperatively than those in the control group (P < 0.05). The K 0.5 and K 1.0 groups each used significantly less NSAID during the 48-hr postoperative period than the control group (P < 0.05). Intravenous administration of ketamine before incision was associated with decreases in pain at rest 6-10 hr postoperatively and a reduction in NSAID requirement after appendicectomy. Administration of ketamine 1.0 mg.kg-1 prior to incision was superior to administration of 0.5 mg.kg-1 in relief of pain on movement after the surgical procedure.

Adhesive bonding of titanium with a thione-phosphate dual functional primer and self-curing luting agents

A consistent bond between the metal framework and the luting agent is desired when resin-bonded prostheses are constructed with titanium. The purpose of this study was to evaluate three different metal primers on titanium bonding. Two sources of titanium (machined 99.9% titanium and cast Titan Ingot JS2) were used. Disk specimens were bonded with eight combinations of three primers and two luting agents (Panavia 21 and Super-Bond C&B), including two controls. Shear bond strengths were determined after 24-h water storage and after 10,000 cycles of thermocycling. Bond strengths were influenced by thermocycling, primer, luting agent and their combinations, but no significant differences were found between the machined 99.9% titanium and the cast ingot. The thione-phosphate dual functional primer (Alloy Primer) was comparable to the phosphate primer (Cesead II Opaque Primer) and the thiophosphate primer (Metal Primer II) for bonding the titanium metals examined. The most durable bond was obtained in three combinations of these primers and one luting agent (Super-Bond C&B).

Influence of formaline cresol on bond strength of adhesive luting agents to dentin

The present study investigates the influence of the pulpotomy agent formaline cresol (FC) on bond strength between dentin and five adhesive systems (Super-Bond C&B, Bistite II, Imperva Dual Set, Panavia 21, and Panavia 21 with AD Gel). After the dentin surfaces of 75 bovine teeth (including 25 control samples) were exposed by grinding, 25 of the samples were soaked in FC for 2 days, and 25 samples were soaked for 7 days. Samples were bonded to acrylic rods using five adhesive systems, and tensile bond strengths were determined after 1-day immersion in water. Data were analysed by analysis of variance and Duncan's new multiple range test, and the fractured surfaces were observed through a scanning electron microscope. The bond strengths were found to be influenced by the type of system, soaking period, and their combination. The bond strength values of three adhesive systems (Super-Bond C&B, Imperva Dual Set Bistite II, and Panavia 21 with AD Gel) decreased after soaking in FC. After 7 days of FC exposure, the highest bond strength (9.8+/-2.9 MPa) was obtained with the Super-Bond C&B system.

[A case of pulmonary actinomycosis radiologically mimicking a lung cancer]

A 59-year-old male clerk consulted in general practitioner due to cough and hemoptysis. A mass shadow was pointed out in the left upper lung field on a chest radiograph. Patient was referred to our hospital for further treatment. Any definitive daiagnosis could not be made after examinations including sputum culture, cytology and TBLB. Because a lung cancer was strongly suspected, an exploratory thoracotomy was performed. Actinomyces was detected by pathological study of excised specimen, with no evidence of cancer. ABPC was administered for two months postoperatively. The patient is doing well without recurrence of actinomycosis 2.5 years after the surgery. Pulmonary actinomycosis presenting a mass shadow on a radiograph may mimick a pulmonary tumor, especially a lung cancer. Pulmonary actinomycosis should be considered in a differential diagnosis of pulmonary lesion thought to be malignant.

[The effects of intravenous anesthetics, propofol, fentanyl and ketamine on the excitability of spinal motoneuron in human: an F-wave study]

We have investigated the effects of various intravenous anesthetics, propofol, fentanyl and ketamine on the excitability of spinal motoneuron using an F-wave analysis in a total of 28 patients. All patients were divided randomly into three groups as follows; 2 mg.kg-1 intravenous bolus injection followed by 6 mg.kg-1.h-1 infusion of propofol (P group), 1 mg.kg-1 intravenous bolus injection followed by 1 mg.kg-1.h-1 infusion of ketamine (K group), and 5 micrograms.kg-1 injection of fentanyl (F group). The F-wave was determined after supramaximal electrostimulation of the median nerve in distal point. After establishing stable baseline values, intravenous injection of one of the three anesthetics was applied. The F-wave was recorded 3 minutes after the time of bolus administration. We found a significant (P = 0.018) reduction of the persistence from 77.5 +/- 15.2 to 40.9 +/- 16.8% in the propofol group. On the other hand, no significant changes in F-wave parameters were found in ketamine, or fentanyl group. These results suggested that motoneuron excitability in spinal cord could be inhibited by anesthetic dose of propofol, but not by ketamine or fentanyl.

Angle-closure glaucoma as a presumed presenting sign in patients with syphilis

BACKGROUND

Angle-closure glaucoma is a well-known sequel to syphilitic interstitial keratitis. This study describes angle-closure glaucoma in the absence of corneal opacity as a presumed presenting sign of syphilis.

CASES

Two patients presented with angle-closure glaucoma with high peripheral anterior synechiae to the level over Schwalbe's line extending the whole circumference of the angle. Neither corneal opacity nor aqueous inflammation was present. Diffuse or localized retinochoroidal degeneration with pigmentation was found in 1 eye of 1 patient and in both eyes of the other patient.

OBSERVATIONS

Fluorescein angiography revealed dotty retinal pigment epithelial damage even in normal appearing areas of the fundus. The patients showed a positive test for Treponema pallidum hemagglutination and also a low titer of serological tests for syphilis. No systemic activity, such as skin rashes, had been noted.

CONCLUSIONS

Syphilis should be considered in patients presenting high peripheral anterior synechiae involving the whole circumference of the angle even in the absence of preceding interstitial keratitis.

Incipient cauda equina syndrome as a model of somatovisceral pain in dogs: spinal cord structures involved as revealed by the expression of c-fos and NADPH diaphorase activity

Segmental and laminar distribution of Fos-like immunoreactive, reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd)-exhibiting and double-labeled (Fos-like immunoreactive and NADPHd-exhibiting) neurons was examined in lower lumbar and sacral segments of the dog spinal cord using the model of multiple cauda equina constrictions. NADPHd histochemistry was used as marker of nitric oxide synthase-containing neurons. The appearance and the time-course of Fos-like immunoreactive, NADPHd and double-labeled neurons was studied at 2 h and 8 h postconstriction characterized as the incipient phase of cauda equina syndrome. The occurrence of Fos-like immunoreactive and NADPHd-exhibiting neurons in fully developed cauda equina syndrome was studied at five days postconstriction. An increase in Fos-like immunoreactivity in superficial laminae (I-II) and an enhanced NADPHd staining of lamina VIII neurons were found. A statistically significant increase in Fos-like immunoreactive neurons was found in laminae I-II and VIII-X 8 h postconstriction, and in contrast, a prominent decrease in Fos-like immunoreactive neurons was found in laminae I-II, accompanied by a statistically significant increase in Fos-like immunoreactive neurons in more ventrally located laminae VII-X at five days postconstriction. Quantitative analysis of laminar distribution of constriction-induced NADPHd-exhibiting neurons revealed a considerable increase in these neurons in laminae VIII-IX 8 h postconstriction and a statistically highly significant increase in NADPHd-exhibiting neurons in laminae VII-X five days postconstriction. Concurrently, the number of NADPHd-exhibiting neurons in laminae I-II was greatly reduced. While a low number of double-labeled neurons was found throughout the gray matter of lower lumbar and sacral segments at 2 h postconstriction, a statistically significant number of double-labeled neurons was found in lamina X 8 h and in laminae VII-X five days postconstriction. The course and distribution of anterograde degeneration resulting five days after multiple cauda equina constrictions are compared with segmental and laminar distribution of Fos-like immunoreactive and NADPHd-exhibiting neurons. Prominent involvement of the spinal cord neurons appearing in the lumbosacral segments at the early beginning and in fully developed cauda equina syndrome results in a Fos-like immunoreactivity and strongly enhanced NADPHd staining of some neuronal pools. Under such circumstances, an early cauda equina decompression surgery is advisable aimed at decreasing or preventing the derangement of the neural circuits in the lumbosacral segments.

Antenatal dexamethasone enhances endothelin receptorB expression in hypoplastic lung in nitrofen-induced diaphragmatic hernia in rats

BACKGROUND/PURPOSE

The hypoplastic lung and persistent pulmonary hypertension (PPH) are the principle causes of high mortality and morbidity in infants with congenital diaphragmatic hernia (CDH). Endothelin-1 (ET-1), which is produced by vascular endothelial cells and some leukocytes, plays a key role in modulating pulmonary vascular tone in PPH. Two different receptors (ET(A) and ET(B)) for ET-1 have been characterized. Binding of ET-1 to ET(A), which is present on smooth muscle cells in fetal lung, results in vasoconstriction. However, binding of ET-1 to ET(B), which is present on endothelial cells results in vasodilation mediated by endogenous nitric oxide. Antenatal glucocorticoid therapy has been shown to prevent abnormal pulmonary arterial structural changes in animal model with CDH. The aim of this study was to investigate the effect of antenatal glucocorticoid administration on ET-1 system in nitrofen-induced CDH hypoplastic lung in rats.

METHODS

A CDH model was induced in pregnant rats after administration of nitrofen on day 9.5 of gestation. Dexamethasone (Dex) was given intraperitoneally on days 18.5 and 19.5 of gestation. Cesarean section was performed on day 21 of gestation. Rat ET-1 protein expression was measured in solubilized lung tissue extracts, by sandwich type enzyme-linked immunosorbent assay (ELISA) analysis. Reverse transcription polymerase chain reaction was performed to evaluate the relative amount of ET-1, ET(A), and ET(B) mRNA expression.

RESULTS

The ET-1 protein and mRNA expression of ET-1 and both receptors were increased significantly in CDH lung compared with controls. Although there was no significant difference in ET(A) mRNA expression between CDH lung with Dex treatment and without Dex treatment, ET(B) mRNA expression was elevated significantly in CDH lung with Dex treatment compared with CDH lung without Dex treatment.

CONCLUSION

These findings suggest that antenatal glucocorticoid therapy may modulate pulmonary vascular tone in CDH hypoplastic lung by selectively upregulating local expression of ET(B).

Administration of antenatal glucocorticoids upregulates peptide growth factor gene expression in nitrofen-induced congenital diaphragmatic hernia in rats

BACKGROUND/PURPOSE

There is increasing evidence to suggest that various growth factors play a crucial role in fetal lung growth and morphogenesis. An array of peptide growth factors regulate cell proliferation, differentiation, and various other cell functions in the developing lung. The aim of this study was to investigate the effect of antenatal glucocorticoids administration on gene expression of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) and transforming growth factor (TGF)-beta1 in nitrofen-induced congenital diaphragmatic hernia (CDH) in rats.

METHODS

A CDH model was induced in pregnant rats after administration of nitrofen. Dexamethasone (Dex; 0.25 mg/kg) was given intraperitoneally on day 18.5 and 19.5 of gestation (term, day 22). Cesarean section was performed on day 21 of gestation. mRNA was extracted from left lung and reverse transcription-polymerase chain reaction (RT-PCR) was performed to evaluate mRNA expression of each growth factors. Relative levels of mRNA were expressed as a ratio of the band density divided by that of beta-actin, a housekeeping gene known to be expressed at a constant level.

RESULTS

Relative mRNA levels of bFGF and TGF-beta1 were decreased significantly in CDH lung compared with controls. Antenatal Dex treatment up-regulated gene expression of bFGF, PDGF, and TGF-beta1 in the hypoplastic CDH lung.

CONCLUSIONS

The authors' findings suggest that decreased gene expression of bFGF, PDGF, and TGF-beta1 in the CDH lung may suppress lung growth and development. Increased gene expression of bFGF, PDGF, and TGF-beta1 in Dex-treated lung suggests that antenatal glucocorticoid administration may accelerate fetal lung growth by up-regulating these growth factors.

Antenatal dexamethasone administration inhibits smooth-muscle-cell DNA synthesis in pulmonary-arterial media in nitrofen-induced congenital diaphragmatic hernia in rats

The aim of this study was to investigate the effect of antenatal glucocorticoid therapy on smooth-muscle-cell (SMC) DNA synthesis in the pulmonary arteries (PA) in a nitrofen-induced congenital diaphragmatic hernia (CDH) rat model following nitrofen administration on day 9.5 of gestation. Antenatal dexamethasone (DEX) was given intraperitoneally on days 18.5 and 19.5 of gestation. Bromodeoxyuridine (BrdU) was injected via a jugular vein into the dam 1 h before the fetuses were killed by cesarean section at term. The fetuses were divided into three groups: group I (n = 10): normal controls; group II (n = 10): nitrofen-induced CDH; group III (n = 10): nitrofen-induced CDH with antenatal DEX treatment. Immunostaining of the lungs with anti-BrdU antibody was obtained by a standard avidin-biotin complex method. The number of immunopositive cells in the PA media and adventitia were counted using an image analyzer and analyzed statistically. The number of BrdU-immunopositive cells in the media was significantly increased in group II (16.83 +/- 3.01) compared to groups I (9.16 +/- 2.20) and III (6.83 +/- 1.70) (P < 0.01). There was no significant difference between groups I and III. The number of BrdU-immunopositive cells in the adventitia was not significantly different between the three groups. Antenatal DEX treatment inhibits SMC DNA synthesis in PA media in CDH lungs. This may be a possible mechanism by which antenatal DEX prevents structural PA changes in nitrofen-induced CDH in rats.

Adhesive bonding of noble metal alloys with a triazine dithiol derivative primer and an adhesive resin

The purpose of this study was to evaluate the bond strength and durability of a metal adhesive system bonded to noble metal alloys. Disc specimens were cast from type IV gold (type IV, Casting Gold M. C., metal-ceramic gold (Au-Pt-Pd, Degudent Universal, metal-ceramic palladium (Pd-Ga-Co, PTM 88 silver-indium (Ag-In-Zn, Salivan Hard and silver-palladium-copper-gold (Ag-Pd-Cu, S12) alloys and pure silver (pure Ag). The specimens were air-abraded with 50 micron alumina, conditioned with a thiol-based primer designed for noble alloys (V-Primer), and then bonded with an adhesive resin (Super-Bond Opaque Ivory). Shear bond strengths were determined after repeated thermocycling (4-60 degrees C, 1 min each, 100 000 cycles). The average bond strengths in MPa (n=8) were 30.9 for the type IV alloy, 29.0 for the Ag-Pd-Cu alloy, 28.0 for the Au-Pt-Pd alloy, 26.3 for the pure Ag, 26.0 for the Pd-Ga-Co alloy and 9.3 for the Ag-In-Zn alloy. The Ag-In-Zn alloy exhibited significantly lower bond strength than the other alloys, whereas the bond strengths of the other four alloys and pure Ag were comparable (P<0.05). It is concluded that the combined use of the thiol derivative primer and the adhesive resin is effective for bonding the noble metal alloys examined, with the exception of the Ag-In-Zn alloy.