Surface Properties of Resin Composites and CAD/CAM Blocks After Simulated Toothbrushing

OBJECTIVES

This study aimed to evaluate the surface gloss, surface roughness, and color change of restorative materials after a three-body wear abrasion.

METHODS AND MATERIALS

Four resin composites with different filler particle size (Gracefil Flo [GFF, 0.7 μm], Gracefil LoFlo [GFL, 0.25 μm], Gracefil ZeroFlo [GFZ, 0.15 μm], and Gracefil Putty [GFP, 0.3 μm]), two CAD/CAM resin composite blocks with different filler particle size (Cerasmart 300 [CS3, 0.7 μm] and Cerasmart Prime [CSP, 0.3 μm], GC), and one CAD/CAM lithium disilicate glass-ceramic block (Initial LiSi Block [ILS], GC) as a control were evaluated. Twenty slab-shaped specimens were obtained from each material. Ten specimens were subjected to 80,000 toothbrushing strokes and measured for surface gloss (Gloss Unit, GU), surface roughness (Ra, μm), and color (L*, a*, and b* values) before toothbrushing and at every 20,000 strokes. Color differences (ΔL*, Δa*, Δb*, and ΔE00) before and after toothbrushing were calculated. After 80,000 strokes, abraded surfaces were observed using scanning electron microscopy. The other 10 specimens were measured for Vickers microhardness (VHN).

RESULTS

After 80,000 toothbrushing strokes, the mean GU ranged from 60.43 to 16.12 (the highest for ILS and lowest for GFL), and the mean Ra ranged from 0.079 to 4.085 (the lowest for ILS and highest for GFL). At all measuring stages, the calculated ΔE00 values ranged from 0.31 to 0.92 for all materials. The mean VHN ranged from 632.34 to 39.08 (the highest for ILS and lowest for GFZ). The resin composite containing the largest filler particle (GFF) showed significantly lower Ra and higher VHN than other resin composites (GFL, GFZ, and GFP). The CAD/CAM resin composite block containing a smaller filler particle (CSP) retained significantly higher GU than that containing a larger filler particle (CS3). A negative correlation between GU and Ra was detected.

CONCLUSIONS

Based on the findings, toothbrush abrasion induced a decrease in GU and an increase in Ra for all resin-based materials tested. Resin-based materials with larger filler size tended to show lower Ra, while resin-based materials with smaller filler size tended to show a smaller reduction in GU. These were more pronounced for light-cure resin composites than for resin composite blocks for CAD/CAM.

Advanced glycation end products and cognitive impairment in schizophrenia

Advanced glycation end products play a key role in the pathophysiology of schizophrenia. Cognitive impairment is one of the central features of schizophrenia; however, the association between advanced glycation end products and cognitive impairment remains unknown. This study investigated whether advanced glycation end products affect the cognitive domain in patients with schizophrenia. A total of 58 patients with chronic schizophrenia were included in this cross-sectional study. Plasma advanced glycation end products were measured using high-performance liquid chromatography (HPLC). Neuropsychological and cognitive functions were assessed using the Wechsler Adult Intelligence Scale, Third Version, and the Wisconsin Card Sorting Test Keio-FS version. Multiple regression analysis adjusted for age, sex, body mass index, educational years, daily dose of antipsychotics, and psychotic symptoms revealed that processing speed was significantly associated with plasma pentosidine, a representative advanced glycation end product (standardized β = -0.425; p = 0.009). Processing speed is the cognitive domain affected by advanced glycation end products. Considering preceding evidence that impaired processing speed is related to poor functional outcome, interventions targeted at reducing advanced glycation end products may contribute to promoting recovery of patients with schizophrenia as well as cognitive function improvement.

[Multiple calcifying fibrous pseudotumor of the pleura]

A newly recognized distinctive fibrous soft tissue lesion called "calcifying fibrous pseudotumor" (CFPT) was recently described in the soft tissue of the extremities, trunk, scrotum, groin, neck, or axilla. But CFPT orgining from the pleura is rare. A 44-year-old woman was admitted to our hospital for an investigation of a chest radiographic abnormality. The complete resection was performed through mini-thoracotomy utilizing video assisted thoracoscopic surgery. Microscopically, the lesion was mostly composing dense collagenous tissue and scattered calcifications. The postoperative course was uneventful and no recurrence is observed 18 months after operation. We report succsessful surgical treatment for multiple CFPTs.

[Esophago-bronchial fistula confirmed with bronchoscopy utilized an indocyanine green]

The patient was a 54-year-old female with both headache and vomit presented to the emergency room. Endoscopic examination revealed an advanced esophageal cancer located on the middle thoracic esophagus. Histological analysis revealed squamous cell carcinoma. The clinical stage was diagnosed as T4N2M0 and this case was treated by the chemoradiation. She presented progressive moist cough after chemoradiotherapy. Esophagography demonstrated esophago-bronchial fistula (EBF). EBF was not detected by routine broncoscopy. To confirm fistula, we were performed the bronchoscopy which utilized an indocyanine green. Contrast media colored green were over from the superior segmental bronchus in a bronchoscope. The bronchoscope which utilized an indocyanine green is effective for EBF.

[New forceps for a sutureless patch technique using sheet materials]

Intraoperative air leaks are often treated by a sutureless patch technique using a fibrin tissue-adhesive collagen fleece or synthetic materials with fibrin sealant. Intraoperatively, the technique of using these materials has been troublesome, therefore air leaks fail to close. Akicette has been applied as an easy sutureless patch technique for air leaks. Seven air leaks (5 were lung cancers, 2 were spontaneous pneumothorax) were treated with Akicette. Akicette is simple to operate with, and can easily carry sheet materials. Using Akicette, the sheet materials tightly adhered onto surrounding the pleural defect without any sliding on the wet lung surface. Akicette is feasible tool for a sutureless patch technique and is useful to easily place the sheet materials.

[Clinical study on video-assisted thoracic surgical simultaneously stapled subsegmentectomy for peripheral lung tumors]

BACKGROUND

The purpose of this study is to confirm the safety and validity of video-assisted thoracic surgical simultaneously stapled subsegmentectomy (simultaneously stapling of all subsegmental bronchi and vessels in their natural construction).

METHODS

The clinicopathologic information of the 10 patients who underwent video-assisted thoracic surgical simultaneously stapled subsegmentectomy for primary lung cancer (6) and metastatic lung tumor (4) were reviewed retrospectively. The patient population consisted of 7 men and 3 women with a mean age of 70.2 years.

RESULTS

Median operative time was 201 minutes. Average blood loss was 76 ml. Mean duration of thoracic drainage was 3 days. There was no surgical mortality. Recurrence was diagnosed in 2 of 6 lung cancer patients (each of contralateral lung metastasis and brain metastasis), and 1 of 2 died 26 months after the operation. All patients have been followed for a mean period of 30.4 months with no local recurrence.

CONCLUSIONS

Video-assisted thoracic surgical simultaneously stapled subsegmentectomy is safe and may be an acceptable alternative to segmentectomy, and wedge resection for strictly selective patients with peripheral lung tumors.

Biochemical and histological features of hepatitis G virus infection

To assess the biochemical and histological characteristics of hepatitis G virus (HGV) infection, we examined four patients who were infected with HGV only (HGV group), and compared them with 16 patients infected with both HGV and hepatitis C virus (HCV; HGV + HCV group) and 18 patients infected with HCV only (HCV group). Biochemical examination showed a significantly low level of serum alanine aminotransferase (ALT) in the HGV group, and that the gamma-glutamyl transpeptidase (gamma-GTP)/ALT ratio in the same group was significantly higher than in the other two groups. Although all three patient groups had a similar degree of liver fibrosis, both the degree of periportal inflammation and total histological activity index were significantly lower in the HGV group than in the other two groups. Fibrous enlargement of the portal tract without lymphoid infiltration and thin fibrous septa was characteristically observed in the HGV group. No significant difference was found between the HGV + HCV group and HCV group. Our results suggest that biochemical and histological changes in HGV infection are very mild and quite different from those of HCV infection.

Emergence and takeover of YMDD motif mutant hepatitis B virus during long-term lamivudine therapy and re-takeover by wild type after cessation of therapy

Treatment of hepatitis B virus (HBV) with lamivudine is effective in suppressing virus replication and results in reduced inflammatory activity. However, the emergence of lamivudine-resistant mutant virus, with amino acid substitution in the YMDD motif of DNA polymerase, has been reported. We report the emergence and takeover of YMDD mutant and re-takeover by wild type during and after long-term lamivudine therapy. YMDD mutants were detected in five patients who showed DNA breakthrough (HBV DNA becoming detectable after a period of DNA negativity), which occurred after 9 to 14 months of lamivudine therapy. Four of five mutants had amino acid sequence YIDD, and the remaining mutant had YVDD. Patients with high HBV-DNA titer and/or hepatitis B e antigen tended to develop breakthrough (P = .038). Using a sensitive and specific polymerase chain reaction (PCR)-based method developed in this study, the emergence of YMDD mutants was detected 1 to 4 months before DNA breakthrough, but not detected in any of the pretreatment sera. The mutants were predominant at breakthrough, but were replaced by wild-type virus 3 to 4 months after cessation of therapy in the two patients who discontinued therapy. One of these patients had a relapse of hepatitis. Mutant continued to replicate in the remaining three patients who continued to receive treatment, and relapse occurred in only one of these patients. Our results suggest that the replication of YMDD mutant viruses is less than wild type and is re-overtaken by wild type after cessation of therapy. Re-administration of lamivudine, possibly combined with other antiviral therapy, might be useful in some patients experiencing hepatitis with lamivudine-resistant variants.

Usefulness of hepatitis C virus RNA counts by second generation HCV bDNA-probe in chronic hepatitis C based on the HCV genotype

Detection of hepatitis C virus (HCV) RNA by a second generation (ver 2) HCV bDNA-probe method (bDNA-probe) was compared with detection by the first generation (ver 1) assay. The two assays were performed simultaneously with the same serum samples of HCV genotypes 1b, 2a, 2b, 3a, and 3b. The positive rates with ver 1 were 82% for HCV genotype 1b (type 1b), 57.6% for HCV genotype 2a (type 2a), 75.0% for HCV genotype 2b (type 2b), 55.6% for HCV genotype 3a (type 3a), and 93.8% for HCV genotype 3b (type 3b). The positive rates with ver 2 were 95.0% for type 1b, 93.9% for type 2a, 83.3% for type 2b, 100% for type 3a, and 93.8% for type 3b. With Fisher's exact test, the detection rate for type 2a was significantly higher (P = 0.001) with ver 2 than with ver 1. We obtained regression lines using the HCV counts measured by bDNA-probe on the y axis and the HCV counts obtained by an HCV reverse transcriptase (RT)-competitive polymerase chain reaction method (competitive PCR) on the x axis. The gradients for types 1b, 2a, and 3b were greater with ver 2 compared to ver 1. The gradients for types 2a and 3b were the highest: for type 2a, y = 0.135x + 0.6 with ver 1 and y = 0.248x + 0.1 with ver 2; for type 3b, y = 0.366x + 0.1 with ver 1 and y = 0.727x + 0.3 for ver 2. In addition, HCV-RNA counts for all the genotypes tested in this study were significantly higher with ver 2 than with ver 1. Hence, we conclude that ver 2 of the bDNA-probe measures HCV-RNA counts closer to those obtained with competitive PCR than the ver 1 assay.

Predictive factors in eradicating hepatitis C virus using a relatively small dose of interferon

Interferon (IFN) can reduce hepatitis C virus load and even eliminate the virus in 30-40% of patients. Several predictive factors for eradication of the virus have been reported and a higher dose of IFN tends to result in elimination of the virus. However, a small dose of IFN sometimes is as effective as a large dose in eradicating the virus. The predictive factors for such a response are not well established. We retrospectively analysed 50 patients with chronic hepatitis C who were treated with relatively small amounts of IFN (equal or less than 252 million units). Eleven patients were responders (elimination of hepatitis C virus (HCV) and normalization of alanine amino transferase (ALT) for at least 6 months), but the remaining 39 were non-responders. Multivariate analysis showed that the pretreatment viral load and total dose of IFN per kilogram of bodyweight were significant predictive factors of response to therapy. We also assessed the amino acid substitutions in the IFN sensitivity determining region (ISDR), NS5A codon 2209-2248, of HCV in serum samples obtained from 31 patients with HCV genotype 1b. The presence of more than one amino acid substitution in the ISDR tended to correlate with HCV genotype 1b elimination. As IFN is expensive and has a number of serious side effects, our study suggests that the optimal dose of IFN may vary from one patient to another and that more stringent criteria should be used to select the optimal dose for therapy.

[Characteristics of home parenteral nutrition and effectiveness of 3 way valved PICC in regional medical care]

Home medical care is becoming a greater matter of concern along with the increasing population of elderly persons. The various difficulties in home care are also found in regional care, and it could be said that in Japan regional care serves as an "advanced model" for home medical care. Ohya Town is located in the mountains of northern Hyogo Prefecture. It has a population of about 5,000 of which 32% is elderly people. There is no railroad, and it takes around 30 minutes to travel to the central hospital from the area. The three town clinics are in contact with each other and with the central hospital concerning medical information. The characteristics of Home Parenteral Nutrition in this underpopulated district are discussed and reported in reference mainly to cases in which the 3 way valved peripherally inserted central venous catheter (Groshong Catheter) is used, in comparison with HPN cases in the city university hospital.

Pretreatment virus load and multiple amino acid substitutions in the interferon sensitivity-determining region predict the outcome of interferon treatment in patients with chronic genotype 1b hepatitis C virus infection

Hepatitis C virus (HCV) genotype 1b and high pretreatment virus load are predictive factors of poor response to interferon therapy in patients with chronic hepatitis C. To further examine the factors predicting the response to interferon in patients with genotype 1b infection, we analyzed 110 consecutive patients with HCV who were treated with a total of 624 million units of lymphoblastoid interferon alfa. Thirty-six patients (33%) were responders, while the remaining 74 patients (67%) were nonresponders. Multivariate analysis showed that a high virus titer (assessed by serum core protein level, P = .0021) and the presence of more than two amino acid substitutions in the interferon sensitivity-determining region (ISDR) (P = .0036) correlated significantly with the response to interferon therapy. Because mutations analyzed by direct sequencing of polymerase chain reaction (PCR) products may reflect artifacts of direct sequencing, we further analyzed quasispecies of HCV in this region by cloning and sequencing. Although PCR-based analysis of responders with multiple amino acid substitutions in the ISDR showed the presence of a small amount of wild-type strain in their serum, the results obtained by direct sequencing and cloning were essentially the same. A longitudinal study of quasispecies in 2 patients who showed a dramatic change in the virus titer showed no conversion from wild type to mutant or vice versa. Our results indicate that amino acid substitutions and virus load are independent predictors of the response to interferon therapy. The ability of some patients with no mutation in the ISDR or high virus load to eliminate the virus suggests the presence of other unidentified factors, host or viral, that influence the response to interferon therapy.

A pilot study of corticosteroid priming for lymphoblastoid interferon alfa in patients with chronic hepatitis C

Interferon treatment reduces the serum level of hepatitis C virus (HCV) and improves inflammatory activity, but relapse is frequently observed. In an attempt to develop a new therapeutic strategy that may reduce relapse and cure the disease, we evaluated the effect of corticosteroid priming on lymphoblastoid interferon alfa in an open randomized clinical trial. The level of HCV RNA increased significantly during corticosteroid priming (from 5.60 [median] to 21.0 x 10(5) Eq/mL; P = .0004) but decreased to the pretreatment level 4 weeks after cessation of corticosteroid (7.0 x 10(5) Eq/mL; P = .07). Sustained normalization of alanine transaminase (ALT) level and virus clearance, confirmed by negative results for HCV RNA using reverse-transcription nested polymerase chain reaction (PCR), were observed over a period of 6 months in 8 of 19 (42.1%) corticosteroid-primed patients, compared with 6 of 19 patients (31.6%) treated with interferon only. A "rebound" of ALT after the withdrawal of corticosteroid was observed in only 2 of 19 patients primed with corticosteroid, but both showed sustained responses. Multivariate analysis for factors predictive of the sustained response indicated that HCV titers measured immediately before interferon therapy and HCV genotype were statistically significant (P = .006 and P = .025, respectively). Our results indicated that corticosteroid priming has a marginal benefit over treatment with interferon alone and that large-scale clinical trials are necessary to determine whether interferon with corticosteroid priming is more effective than interferon alone.

Nuclear DNA content in dimethylhydrazine-induced colonic carcinoma and mucosal dysplasia in rats

Mucosal dysplasia and carcinoma infiltrating the submucosal layer were induced in rats with dimethylhydrazine. The nuclear DNA content of the cells was measured, and the correlation between the DNA distribution pattern and histopathologic findings was evaluated. In mild and moderate dysplasias, histograms of the nuclear DNA content showed a narrow range of distribution with a sharp peak in the diploid area. In severe dysplasia, however, there was wide distribution and no peak value; this was reminiscent of carcinoma. Based on the findings of this report, the authors suggest that severe dysplasia be regarded as intramucosal carcinoma.

Intraoperative colonoscopy for the diagnosis of multiple cancers of the large intestine

Seventeen patients with multiple simultaneous cancers of the large intestine were investigated. Three out of 4 patients with multiple advanced cancers were correctly diagnosed preoperatively. Multiple cancerous lesions of early and advanced stages coexisted in 13 patients, and it was possible to diagnose the existence of multiple cancers in only 5 preoperatively. A study on the preoperative detectability of coexisting early cancers showed that early lesions located distally to the advanced ones were frequently detected, however, subsidiary lesions located proximally tended to be overlooked. Hence, intraoperative colonoscopy was performed in patients with cancer of the large intestine whenever there was a portion that had not been adequately inspected prior to surgery. Of 31 patients subjected to this examination, 5 had a total of 7 polypoid lesions, in one case we found evidence of a small advanced cancer which was not detected preoperatively.

Significance of pelvic retroperitoneal pneumography in the assessment of extramural invasion of rectal carcinoma

Pelvic retroperitoneal pneumography (PRP) and barium enema were performed simultaneously in 34 patients with rectal carcinoma in an attempt to assess whether there was extramural cancer invasion. In 9 patients, no free air was visualized in the retroperitoneal cavity surrounding the mass, and histological evaluation of the excised specimens showed extramural invasion in all 9. The mean maximum diameter was 4.1 cm. In 25 patients, free air was seen around the mass, and 10 had tumors limited to the rectal wall, the remaining 15 manifested extramural invasion, however, the mean diameter was small (2.0 cm). In a mass whose center was located along the anterior rectal wall, it was difficult to assess from the free air findings whether there was extramural invasion. Based on the present findings, we concluded that PRP is useful in determining preoperatively whether there is extramural invasion in cases with rectal carcinoma involving the posterior and lateral walls.

Results of total gastrectomy for gastric cancer

To compare the results of total gastrectomy performed during the last 30 years, we classified 256 patients into four chronologic groups. Despite advances facilitating early detection of gastric cancer, the percentage of patients with stage IV cancer was not significantly different among the four groups. However, operative mortality decreased and curability increased in the two most recent groups. The 5 year survival rate was significantly increased in patients operated on after 1960. Our results show that in Japan, operative mortality and 5 year survival compare favorably with reports from Western countries.

Therapeutic significance of noncurative gastrectomy for gastric cancer with liver metastasis

The therapeutic significance of noncurative gastrectomy for gastric cancer with liver metastasis was evaluated and the histologic characteristics of such cancer examined. The mean postoperative survival time of patients with liver metastasis limited to one lobe or a few scattered metastases to both lobes without peritoneal metastasis or direct cancer invasion to other organs was significantly prolonged by noncurative gastrectomy. Differentiated adenocarcinoma, including papillary adenocarcinoma, and intravenous cancer invasion were found to be the histologic characteristics of gastric cancer with liver metastasis.

Spontaneous stomach ulcer in genetically mast-cell depleted W/Wv mice

Histamine has been implicated in the pathogenesis of gastroduodenal ulcers. Since mast cells contain a considerable amount of histamine as well as heparin and other biologically active substances, it seems reasonable to speculate that they are involved in this process. In fact, development of gastroduodenal ulcers was reported in dogs with mastocytoma, and an increase in mast-cell number was described in the vicinity of human gastroduodenal ulcers. Y.K. et al. have recently found that the number of mast cells in a unit length of the skin of W/Wv mutant mice is less than 1% of the value for the congeneic +/+ mice and that no mast cells are detected in the intestinal canal of W/Wv mice. Therefore, this mutant mouse was used to investigate the role of mast cells in the induction of gastroduodenal ulcers. As a preliminary experiment, we examined the stomach and duodenum of W/Wv mice without any treatments. Unexpectedly, we found the spontaneous development of perforating stomach ulcers in W/Wv mice, suggesting that mast cells do not necessarily have aggravating effects on the production of stomach ulcers.

Development of haematopoietic colonies on the macrophage layer formed in the peritoneal cavity of S1/S1d mice

The colony-forming ability of haematopoietic cells was examined on the macrophage layer formed in the peritoneal cavity of S1/S1d mice. The bone marrow cells of the congenic +/+ mice formed many macroscopic colonies on the macrophage layer of the S1/S1d mice although they did not form macroscopic colonies in the spleens of the same S1/S1d recipients. The size and the differentiation pattern of colonies on the macrophage layer of the S1/S1d mice were comparable to those of the colonies on the macrophage layer of the +/+ mice. There are two possible explanations for these results: (a) The microenvironmental defect of the S1/S1d mice has a more prominent effect on the development of spleen colonies than that of macrophage-layer colonies because 'Steel' locus may not be expressed significantly in the peritoneal macrophages or (b) because the cells that make colonies on the macrophage layer may be more differentiated cells than the multipotential stem cells that make colonies in the spleen.

A probable case of Leishmaniasis (Espundia) acquired in Japan

A case of mucocutaneous leishmaniasis is described in a Japanese patient who had never been abroad, suggesting either contact with an infected person from Brazil or the presence in Japan of indigenous cutaneous leishmaniasis. This case illustrates the value of electron microscopic examination in such infections, since it provided the definitive diagnosis.

Development of hematopoietic spleen colonies in nonirradiated genetically normal mice

The question as to whether prior irradiation or injection of cytotoxic drugs is essential for the development of spleen colonies was examined in genetically normal mice. Mixtures of lymph node and bone marrow cells from C57BL mice were injected into (C57BL X CBA-T6T6) F1 hybrid mice without pretreatment. Hematopoietic nodules were observed in the spleens of F1 hybrid mice killed 18 days after injection. The average number of nodules increased linearly with increased numbers of injected bone marrow cells. Hematopoietic stem cells (CFU-S) and dividing cells in the nodules were shown to be of C57BL origin. Histologic examination showed that erythroid cell colonies predominated over granulocytic cell colonies. These results suggest that any kind of treatment that causes the depletion of CFU-S in the spleen of hosts would provide a suitable environment for the production of colonies by transplanted CFU-S.