Micro-shear bond strength of dual-cured resin cement to glass ceramics.

OBJECTIVES: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-cured resin cement to bond to glass ceramics designed for in indirect adhesive restoration. METHODS: A cast glass ceramic (Olympus Castable Ceramics) with a crystalline phase consisting of mica and beta-spondumene was selected as the substrate material. The glass surfaces, which were sandblasted, polished, or etched with phosphoric acid or hydrofluoric acid (HF), were bonded with a dual-cured resin cement (Panavia Fluoro Cement) using a dentin adhesive system (Clearfil SE Bond), both with and without a silane coupling agent. A micro-shear bond test was carried out to measure the bond strength of the resin cement to the glass surface. Each glass surface was bonded and tested using the shear test. In addition, surfaces with the bonding removed after the shear bond test, the adhesive interface between the glass and cement, and an etched glass surface without any bonding, were studied morphologically using scanning electron microscopy or field emission scanning electron microscopy. RESULTS: Usage of a silane coupling agent effectively raised the bond-strength values of resin cement (Fisher's PLSD, P<0.01). The effectiveness of using phosphoric acid etching to improve bonding was not clear (Fisher's PLSD, P>0.01). HF-etching for 30s seemed to over-etch the glass surface, resulting in adverse effects on bonding (Fisher's PLSD, P<0.01). SIGNIFICANCE: The micro-shear bond strength between Olympus Castable Ceramics and resin cement can be increased by the silane coupling agent used along with an acidic primer.     

Measurement of intrahepatic shunt using Rutland method

Intrahepatic shunt ratio was calculated from the fraction of the uptake constant and the blood background, analyzing the data of 99mTc-(Sn)-N-pyridoxyl-5-methyltryptophan (99mTc-PMT) hepatobiliary imaging by Rutland method. Shunt flow and total hepatic blood flow (THBF) were also calculated from the values for the effective hepatic blood flow (EHBF) estimated from the blood clearance technique. In 15 cases of normal volunteer, the average of the shunt ratio, shunt flow, and THBF were 18.4 +/- 5.4 (S.D.)%, 137.8 +/- 49 ml/min, and 753 +/- 83.2 ml/min, respectively. In 8 cases of chronic hepatitis, the values were 35.2 +/- 2.6%, 276 +/- 55.4 ml/min, and 794.1 +/- 119.4 ml/min, respectively. In 12 cases of liver cirrhosis, the values were 51.4 +/- 12.6%, 353.9 +/- 141.3 ml/min, and 685.6 +/- 174.8 ml/min, respectively. In cases of chronic hepatitis and liver cirrhosis, in comparison with normal cases, the values for the shunt ratio and shunt flow were significantly increased (p less than 0.001) and those for EHBF were significantly decreased (p less than 0.001), but those for THBF were not significantly altered. There was a significant inverse correlation between the shunt ratio and EHBF (r = -0.842) in all 35 cases. This method is considered to be useful for differential diagnosis, estimation of the grade of the diseases, and evaluation of pathophysiology of various diffuse liver diseases.     

Comparison of transfer and distribution of technetium and rhenium in radish plants from nutrient solution

Tracer experiments were carried out to compare the plant uptake behavior of Tc and Re from nutrient solutions. Radish plants, transplanted to nutrient solution including various tracers, showed the same uptake and distribution of ^95mTc and ¹⁸³Re. The trend was the same when the ⁹⁹Tc and stable-Re concentrations were increased in nutrient solution. The behavior of other elements was different from that of Tc and Re. These findings suggest the possible use of Re as the chemical analogue of Tc in soil solution to plant uptake experiments.     

Immunohistologic analysis of the phenomenon of spontaneous regression of numerous flat warts

Among various tumors induced by human papilloma virus (HPV), flat warts are unique in that they show a systemic regression phenomenon after sudden occurrence of inflammation in all the tumors, leaving permanent immunity to flat warts in the host. When studied immunohistochemically, the presence of HPV antigen using papilloma virus genus-specific antiserum in 31 cases of regressing flat warts was not found; whereas it was demonstrated in the nuclei of upper epidermal cells of ordinary flat warts in 12 of 19 cases (63%). T-cell phenotype assessment in nine regressing flat warts using monoclonal antibodies showed that helper/inducer subsets constituted a major peritumoral dermal infiltrate with a moderate number of intermingling OKT6+ cells. In contrast, the tumoral epidermis was invaded by almost equal number of suppressor/cytotoxic T-cells and helper/inducer T-cells, where at least some keratinocytes also expressed HLA-DR antigen in addition to Langerhans cells. Most T-cells expressed HLA-DR antigen, a marker of activation, but only a small number of them were Tac antigen+, i.e., bearing interleukin 2 receptors. Leu 7+ natural killer cells were seldom found in the infiltrate. These data provide evidence that T-cell-mediated immune attack against tumor cells and not against intranuclear HPV antigen, induces the systemic spontaneous regression of numerous flat warts in humans.     

Antigenicity of cryopreserved arterial allografts: comparison with fresh and glutaraldehyde treated grafts

The use of cryopreserved aortic allografts in cardiovascular surgery is widespread and has resulted in excellent outcomes. However, it is controversial whether cryopreservation suppresses the antigenicity of tissue. We designed experimental models to study whether the cryopreservation process alters antigenicity in comparison with that found in fresh and glutaraldehyde treated tissues. Fresh, cryopreserved, and glutaraldehyde treated thoracic aorta from Brown Norway rats were subcutaneously implanted into Lewis rats. Inflammatory cells infiltrating around the grafts were measured on days 7, 14, 28, and 56 after implantation. The glutaraldehyde treated grafts showed significantly less infiltration than the fresh or cryopreserved grafts (p < 0.005). No significant difference was detected between the fresh and cryopreserved grafts. Another study examined the effect of modifications of the aortic allograft on subsequent allogeneic skin graft antigenicity. Subcutaneous implantation of fresh, cryopreserved, and glutaraldehyde treated aortic grafts from Brown Norway into Lewis rats resulted in subsequent skin graft rejection at 4.4+/-0.7, 5.1+/-0.8, and 6.6+/-2.1 days, respectively. There was no significant difference between the fresh and cryopreserved groups; whereas skin grafts in the glutaraldehyde group survived longer than those in the cryopreserved group. These results indicate that cryopreservation had no significant influence on antigenic suppression of arterial allografts.     

Elemental distributions and microtensile bond strength of the adhesive interface to normal and caries-affected dentin

The aim of this study was to evaluate the microtensile bond strength (microTBS) and the elemental contents of the adhesive interface created to normal versus caries-affected dentin. Extracted human molars with coronal carious lesions were used in this study. A self-etching primer/adhesive system (Clearfil Protect Bond) was applied to flat dentin surfaces with normal and caries-affected dentin according to the manufacturer's instructions. After 24 h water storage, the bonded specimens were cross-sectioned and subjected to a microTBS test and electron probe microanalysis for the elemental distributions [calcium (Ca), phosphorus (P), magnesium (Mg), and nitrogen (N)] of the resin-dentin interface after gold sputter-coating. The microTBS to caries-affected dentin was lower than that of normal dentin. The demineralized zone of the caries-affected dentin-resin interface was thicker than that of normal dentin (approximately 3 microm thick in normal dentin; 8 microm thick in caries-affected dentin), and Ca and P in both types of dentin gradually increased from the interface to the underlying dentin. The caries-affected dentin had lost most of its Mg content. The distributions of the minerals, Ca, P, and Mg, at the adhesive interface to caries-affected dentin were different from normal dentin. Moreover, a N peak, which was considered to be the collagen-rich zone resulting from incomplete resin infiltration of exposed collagen, was observed to be thicker within the demineralized zone of caries-affected dentin compared with normal dentin.     

Dorsal root identification using spinal endoscopy and electro-physiology

We aimed to develop a method of accurately identifying the dorsal root for the corresponding peripheral afferent nerve under endoscopic observation. We developed an endoscope with an external diameter of 1.8 mm. After small laminectomy on the lower thoracic vertebrae, we inserted this endoscope carefully into the epidural and then subarachnoid spaces. We observed structures in these spaces with the endoscope. We tried to determine the spatial relationship between these electrodes and dorsal root. After identifying each space, we inserted two electrodes into the visualized space to record evoked potentials; a bipolar electrode (protocol 1) and a catheter-type eight polar electrode (protocol 2). Each pole could be distinguished by marks. To stimulate peripheral nerves, we inserted needle-type electrodes into Th 10, 11 and 12 intercostal nerves. We attempted to record potentials from dorsal surface of the cord generated by intercostal nerve stimulus. Protocol 1: We moved the position of the bipolar recording electrodes between Th 9 and L 1 by 1 cm increment, and obtained evoked potentials correspondingly. Protocol 2: We chose the neighboring pairs of poles sequentially from the tip of the catheter for bipolar recording. At the end of each experiment, we dissected the animal and checked the intercostal nerve originating from the root. With the endoscope, we could clearly observe structures in the epidural and subarachnoid spaces. We could record evoked potentials from the dorsal spinal cord with the electrodes located either in epidural or in subarachnoid spaces. Shapes of evoked potentials changed characteristically according to the relative position between the root and the electrode. The largest potentials were obtained when the electrode was nearest to the dorsal root, of which the peripheral nerve was being stimulated. By combining endoscopy with the electrophysiological technique, we could accurately identify the dorsal roots for the corresponding peripheral afferent nerves. This method may be used for the selective dorsal root blockade under the visual field.     

REP-1 gene mutations in Japanese patients with choroideremia

· Background: Choroideremia (CHM) is an X-linked progressive dystrophy of the choroid, retinal pigment epithelium, and retina. Recently, the REP-1 gene was isolated and the causative mutations in the gene were detected in patients with CHM. In a previous study, we described a Japanese family with CHM who had a mutation in the REP-1 gene. In the present study, we performed extensive analysis of the REP-1 gene in patients with CHM from several institutions in Japan. · Methods: Twenty-six patients with CHM and 5 unaffected females from 22 independently ascertained families were examined. Exons 1–15 of the REP-1 gene were screened by single-strand conformation polymorphism. The DNA fragments suspected of any variations were directly sequenced. · Results: Fifteen different mutations, including one previously reported mutation, were detected in 18 families. In addition, carrier status was proven in four unaffected females found to be heterozygous for the mutant allele. · Conclusions: Fifteen different mutations of the REP-1 gene were detected in 18 Japanese families. There were no hot spots for the mutations and no missense mutations. The results show that REP-1 gene defects cause CHM in Japanese patients, and the mutations in these Japanese patients differed from the mutations reported for CHM patients in Europe, Canada, and America except for R267X and 1313delTC. These findings suggest that the mutations occurred independently in the Japanese patients. Received: 13 August 1998 Revised version received: 16 November 1998 Accepted: 9 December 1998     

Dermal Melanocytosis of the Helix

Abstract: A 2‐year‐old Japanese boy had a congenital gray‐blue macule involving the right helix along with a few melanotic spots on both sclerae. Histopathology showed dermal melanocytosis. Q‐switched alexandrite laser treatment induced a good cosmetic response. This patient shows the overlap between Ota and Ito nevi, and we suggest dermal melanocytosis is better used as a generic term for these unusual pigmentations.