Effect of Er:YAG laser irradiation on acid resistance to bovine dentin in vitro

Resin bond strength to Er:YAG laser irradiated dentin has been reported to be lower than that of unlased dentin. The reasons have been much discussed, but not clarified. One hypothetical cause has been discussed that lased dentin is acid resistant, therefore, the etching effect of acid conditions decreases. The purpose of this study was to evaluate the acid resistance of laser-irradiated dentin and compare it with the dissolved mineral of Er:YAG laser irradiated dentin and unlased dentin. This experiment was a pilot study to assess the etching effect of pre-conditioner for resin bonding to lased dentin. Bovine dentin was irradiated by Er:YAG laser and immersed in 0.1 M lactic buffer solution (pH 4.0). The dissolved Ca and P in the solution were then both measured. Dissolved Ca from lased dentin was not significantly different from that coming from unlased dentin (p > 0.05). The molar ratio of Ca/P did not differ significantly between lased and unlased dentin, either (p > 0.05). Under FE-SEM view before immersion, the dentin surface was covered with a smear layer in unlased dentin, but this layer was not clearly observed in lased dentin. These results suggested that the lased dentin had little or no resistance to lactic buffer solution.     

A patient with primary Sj?gren's syndrome featuring polyneuropathy and oculomotor paralysis and associated with asymptomatic left middle cerebral artery stenosis]

We report a case of primary Sj?gren's syndrome (primary SjS) with polyneuropathy and right oculomotor paralysis associated with middle cerebral artery stenosis. A 39-year-old woman developed progressive numbness and clumsiness of the limbs. Two months later, right third cranial palsy manifested itself and she was admitted to our hospital. A cranial MRA showed left middle cerebral artery stenosis confirmed by transcranial color doppler sonography. A nerve conduction study showed a decrease in the NCV and reduced CMAP, while sural nerve biopsy showed axonal degeneration and infiltration of inflammatory cells around the small blood vessel walls. The patient complained of dry mouth and a salivary gland biopsy revealed inflammatory changes, while salivary gland scintigraphy showed diminished secretion. These findings led to the diagnosis of Sj?gren's syndrome. Reports of primary SjS with involvement of large cerebral arteries are rare. In our case, polyneuropathy and oculomotor paralysis were the manifest symptoms, but middle cerebral artery stenosis was also observed. This indicates that, even in the absence of CNS symptoms, cerebral artery involvement may be present in primary SjS.     

Clinical implication of florid reactive follicular hyperplasia in Japanese patients 60 years or older: a study of 46 cases

Florid reactive follicular hyperplasia (FRFH) of the enlarged lymph node in middle-aged or elderly patients requiring biopsy is a relatively uncommon phenomenon as compared with that in younger age groups. Between 1984 and January 2004, we encountered 46 patients, aged 60 years or older, in whom histology of biopsied lymph node specimens showed inappropriate FRFH for the patient's age. An apparent cause of lymphadenopathy was initially identified in 17 cases (37%): 11 with autoimmune disease and related disorders, 3 with cancer-reactive lymphadenopathy, 2 with Epstein-Barr virus-associated lymph node lesion exhibiting transient autoimmune-disease-like clinical findings, and 1 with atypical mycobacterial infection. Among 29 patients without specific etiology, 16 patients (55%) exhibited histologic findings of progressive transformed germinal center (PTGC). Only 1 of our patients developed malignant lymphoma during the follow-up period. The present study indicates that PTGC is included in the etiology of FRFH in elderly Japanese patients as well as imbalance of the immune system such as autoimmune-disease-associated lymphadenopathy and idiopathic plasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemia. By in situ hybridization, Epstein-Barr virus genomes were demonstrated in only 6 (15%) of 39 cases examined.     

Granulation tissue formation by nonspecific inflammatory agent occurs independently of macrophage galactose-type C-type lectin-1

The role of a macrophage galactose-type calcium-type lectin-1 (MGL1) in antigen-independent granulation tissue formation was investigated. Granulation tissue was induced by injection of carrageenan in an air pouch and distribution of macrophages expressing MGL1/2 was histologically examined. MGL1/2-positive cells were not observed in the granulation tissue induced by carrageenan though these cells were present in dermis. This was distinct from the fact that MGL1/2-positive cells were abundant in granulation tissue induced by antigenic stimulation. CD11b-positive cells were in dermis and carrageenan-induced granulation tissue. Because antigen-induced granulation tissue formation was previously shown to decrease in MGL1-deficient mice or after treatment with anti-MGL1 antibody, we investigated the effects of MGL1-deficient status on carrageenan-induced granulation tissue formation. The thickness of granulation tissue was almost identical between wild-type and MGL1-deficient mice. It is highly likely that MGL1-positive cells are not involved in tissue remodeling when inflammation is driven by nonspecific stimuli.     

Conformational changes in the antibody constant domains upon hapten-binding

Bacterial proteins A and G (SpA and SpG) are immunoglobulin receptors that can be used as probes for monitoring change in the conformation of heavy chain constant (C(H)) domains. Interaction of anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) antibody (Ab) with SpA and SpG were measured by isothermal titration calorimetry and surface plasmon resonance in order to address the question of whether hapten-binding induces a conformational change in the C(H) domain. The interactions of IgG2a or its enzymatic fragments with SpA were measured in the presence or absence of the hapten. Although binding of Fab and F(ab')2 fragments were not observed to free SpA, they did bind to immobilized SpA. In addition, the association constant (K(a)) for interaction of IgG2a with immobilized SpA was approximately 20-fold higher than that with free SpA. This was explained in terms of high avidity resulting from multivalent interaction between IgG2a and immobilized SpA on the chip. Interestingly, the hapten-binding weakened the interaction between the F(ab')2 fragment and SpA. Furthermore, approximately half of the IgG2a was incapable of binding to immobilized SpA in the presence of hapten. These results were explained using a model which assumed the formation of two kinds of SpA/IgG complexes; one through sites on F(ab')2 arms and the other through sites on the Fc region. The former type dissociated as a result of hapten-binding, as did the F(ab')2 fragment and suggested that a conformational change had occurred around the Fab arms, while the latter type did not dissociate because of the higher avidity of the Fc region. However, using a mutant SpA with a lower K(a) value for the interaction with IgG2a, it was shown that hapten-binding induced long range conformational changes in the Fc region of IgG2a. Similar evidence of conformational change upon hapten-binding was also obtained using SpG as a probe.     

Coverage by Japanese newspapers of oral health messages on the prevention of dental caries

The purpose of this study was to estimate the coverage and quality of information on dental caries prevention in Japanese newspapers. Newspaper articles were searched using database during 10 years from 1993 to 2002. From five major newspapers, 440 articles concerning dental caries prevention were selected and used for analysis. The number of caries prevention articles was related to National Oral Health Week, which was held in June of each year, and the introduction of new policy or government statements on oral health issues. Major sources of articles came from manufacturing companies (29.3%), staff of universities (27.7%), and other dental specialists (20.2%). Caries prevention articles appeared frequently in the health columns (35.7%) followed by news articles (20.0%) and business columns (17.7%). Dietary control (47.5%) was the most frequently described preventive method. Plaque control was referred to in 40.9% of articles, and information about improvement of host factors was provided in 40.0%. Among them, fluoride information was included in 30.0%. Clearly wrong information against evidence based were found in 24 articles. It is important that newspapers provide accurate information with a supportive evidence base. Dental professionals in Japan should be aware of the importance of media advocacy in order to provide appropriate oral health information to the public.     

Renal clearance of perfluorooctane sulfonate and perfluorooctanoate in humans and their species-specific excretion

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are detected in the environment, as well as more specifically in wildlife and humans. However, the toxicokinetic aspects of perfluorochemicals in humans are unclear. In this study, we measured concentrations of PFOA and PFOS in subjects who had lived in Kyoto city for more than 10 years. The serum concentrations of PFOA and PFOS were higher in females who menstruated than those who did not menstruation (P<0.01), but in males this did not change by age; the levels in females reached those in males at an age of 60 years. We then determined the renal clearances of PFOA and PFOS in young (20-40 years old, N=5 for each sex) and old (60 years old, N=5 for each sex) subjects of both sexes. All young females were menstruating, while all old females were not. The renal clearances were 10(-5)-fold smaller than the glomerular filtration rate in humans, suggesting the absence of active excretion in human kidneys. The renal clearances of PFOA and PFOS were approximately one-fifth of the total clearance based on their serum half-lives, assuming a one-compartment model. The sex differences in renal clearance that have been reported in rats and Japanese macaques were not found in our human subjects. We tried to build a one-compartment pharmacokinetic model using the reported half-lives in human. The model was simple but could predict the serum concentrations in both males and females fairly well. We therefore suggest that an internal dose approach using a pharmacokinetic model should be taken because of the large species differences in kinetics that exist for PFOA and PFOS.     

Percutaneous radiofrequency lumbar facet rhizotomy guided by computed tomography fluoroscopy

X-ray fluoroscopy-guided percutaneous radiofrequency facet rhizotomy is used to treat chronic low back pain. The traditional fluoroscopic approach to the medial branch of the posterior rami, however, is associated with a small incidence of complications. We describe a new method for radiofrequency lumbar facet rhizotomy in which computed tomography (CT) fluoroscopy is used to guide needle placement. Three patients with chronic intractable low back pain underwent CT fluoroscopy-guided percutaneous facet rhizotomy. After the safest and shortest route to the target site was determined on the CT image, the needle was advanced along the predetermined route under real-time CT fluoroscopy. When the needle tip was located at the target site, electrical stimulation was applied to verify proper electrode placement. After confirming the clinical effect and lack of complications under test block with a local anesthetic, denervation was performed using radiofrequency current. Pain scores of all patients were reduced after the procedure without any complications such as paralysis or neuritic pain. None of the patients complained of severe discomfort during the procedure. CT fluoroscopy-guided percutaneous lumbar facet rhizotomy appears to be safe, fast, and effective for patients with lumbar facet pain.     

A case of therapy-related leukemia/myelodysplastic syndrome following treatment of refractory testicular germ cell tumor

We report a patient with a refractory testicular non-seminomatous germ cell tumor (NSGCT) who developed therapy-related leukemia (TRL) after undergoing salvage chemotherapy and multiple operations for repeat recurrences. Fifty months after the initial therapy, pancytopenia and myeloblasts were observed in the patient's peripheral blood while the patient was undergoing salvage chemotherapy for a fifth recurrence. A bone marrow examination showed evidence of myelodysplastic syndrome (MDS) and refractory anemia with excess of blasts in transformation (RAEB in T) under French-America-British (FAB) classification. Cytogenetic 5q-/7q- abnormalities were also observed. The patient had received a total dose of 189g/m2 of Ifosfamide, 8,250mg/m2 of Etoposide and 1,450 mg/m2 of Cisplatin; therefore, he was diagnosed as having TRL/MDS. The patient has received induction chemotherapy for TRL with Cytarabine, Daunorubicin and Fludarabine while a bone marrow transplantation has been scheduled. Recently, TRL associated with chemotherapy are being reported with increasing frequency in the literature. Since early detection and treatment are necessary for the management of TRL, peripheral blood examinations should be performed after a diagnosis of refractory germ cell tumor has been made. If pancytopenia is detected, bone marrow and cytogenetic examinations should be immediately performed to rule out TRL.