Biomedical subjects

Y Yoshida

Publications and source records attributed to Y Yoshida.

At least 55 records · Page 3Linked to original sources

PubMed2004

Comparative study on adhesive performance of functional monomers.

Mild self-etch adhesives demineralize dentin only partially, leaving hydroxyapatite around collagen within a submicron hybrid layer. We hypothesized that this residual hydroxyapatite may serve as a receptor for chemical interaction with the functional monomer and, subsequently, contribute to adhesive performance in addition to micro-mechanical hybridization. We therefore chemically characterized the adhesive interaction of 3 functional monomers with synthetic hydroxyapatite, using x-ray photoelectron spectroscopy and atomic absorption spectrophotometry. We further characterized their interaction with dentin ultra-morphologically, using transmission electron microscopy. The monomer 10-methacryloxydecyl dihydrogen phosphate (10-MDP) readily adhered to hydroxyapatite. This bond appeared very stable, as confirmed by the low dissolution rate of its calcium salt in water. The bonding potential of 4-methacryloxyethyl trimellitic acid (4-MET) was substantially lower. The monomer 2-methacryloxyethyl phenyl hydrogen phosphate (phenyl-P) and its bond to hydroxyapatite did not appear to be hydrolytically stable. Besides self-etching dentin, specific functional monomers have additional chemical bonding efficacy that is expected to contribute to their adhesive potential to tooth tissue.

Adhesiveness↗

PubMed2004

Clinical and immunohistochemical characteristics of benign giant cell tumour of bone with pulmonary metastases: case series.

PURPOSE: Giant cell tumour of bone with pulmonary metastases is rare. However, some patients die of pulmonary metastases, and histological examination cannot distinguish between benign tumour and malignant metastases. In this study, we present clinical and immunohistochemical findings associated with giant cell tumour of bone with pulmonary metastases. METHODS: Five patients with benign giant cell tumour of bone with pulmonary metastases (one man and 4 women) were studied. Patients' ages ranged between 20 and 23 years (mean age, 21.8 years). Tumours were in the distal femur in 2 cases, and in the proximal tibia, distal tibia, and lumbar spine in one case each. The tissue specimens from primary tumours, recurrent tumours, and pulmonary metastases were studied using immunohistochemical techniques. RESULTS: Three of the 5 primary tumours were of the spontaneous regression or growth cessation type, or the continuously slow-growing type, showing 4.2% to 6.2% of positive cells for Ki-67 after immunohistochemical staining. However, 2 patients with the rapid-growing type of disease died of pulmonary metastases; their primary, recurrent, and metastatic tumour specimens contained 9.0% to 11.5% of positive cells for Ki-67. CONCLUSION: Three of the 5 primary tumours had a benign clinical pattern and immunohistochemistry. Two of the 5 patients died of pulmonary metastases, which had an aggressive clinical pattern and a high prevalence of positive cells in Ki-67. Examination of Ki-67 should be carried out for aggressive type of giant cell tumour.

Adult↗

PubMed2004

[Pleuropneumonectomy for pulmonary tuberculosis and chronic tuberculous empyema].

Surgical intervention is often necessary to treat either the active pulmonary tuberculosis or its sequelae such as destroyed lung, tuberculous empyema, and bronchial stenosis. Pleuropneumonectomy, which has been reported to be associated with high mortality and morbidity, is performed when the pleural space is completely obliterated due to previous inflammation or when preoperative empyema is complicated. In this article we report 3 patients receiving pleuropneumonectomy for pulmonary tuberculosis or chronic tuberculous empyema in recent 3 years. The mean operation time is 5 hours and 56 minutes, and the mean volume of intraoperative bleeding amounted to 1,417 ml. Autologous blood transfusion was prepared for all 3 patients and transfused them during the operation. No mortality, but postoperative complications were seen in 2 patients (67%) with a history of diabetes mellitus. They were sternum infection and bronchopleural fistula, which were successfully treated conservatively. Diabetes mellitus is thought to be a major risk factor for not only tuberculous disease itself, but also postoperative morbidity. As for surgical techniques, wide skin incision with multiple thoracotomy is necessary to keep a good operative field, and special care must be taken for great vessels and nerves at extrapleural dissection. We conclude that pleuropneumonectomy is relatively risky but effective surgical procedure for adequately selected patients with destroyed lung and tuberculous empyema.

Aged↗

PubMed2003

CSF hypocretin levels in Guillain-Barré syndrome and other inflammatory neuropathies.

CSF hypocretin-1 was measured in 28 Guillain-Barré syndrome (GBS), 12 Miller-Fisher syndrome, 12 chronic inflammatory demyelinating polyneuropathy (CIDP), and 48 control subjects. Seven GBS subjects had undetectably low hypocretin-1 levels (<100 pg/mL). Hypocretin-1 levels were moderately reduced in an additional 11 GBS, 5 Miller-Fisher syndrome, and 1 CIDP subject. Low levels in GBS occurred early in the disease and were associated with upper CNS level abnormalities.

Adolescent↗

PubMed2003

Narcolepsy in a hypocretin/orexin-deficient chihuahua.

A two-year-old male chihuahua suffered attacks of muscle weakness and immobility, although it had no family history of paroxysmal attacks. No neurological or blood biochemical abnormalities were recorded when it was first examined. The attacks were typically elicited by stimulation, such as feeding, and a case of sporadic narcolepsy-cataplexy was therefore suspected. Treatment orally three times a day with 1 mg/kg imipramine, was effective in reducing the attacks. The concentration of hypocretin-1/orexin A in the dog's cerebrospinal fluid was less than 80 pg/ml (22.5 pmol/litre), compared with normal canine levels of 250 to 350 pg/ml (70.0 to 98.3 pmol/litre), supporting a diagnosis of hypocretin-deficient narcolepsy.

Adrenergic Uptake Inhibitors↗

PubMed2003

Dysferlin mutations in Japanese Miyoshi myopathy: relationship to phenotype.

OBJECTIVE: To study dysferlin gene mutations and genotype-phenotype correlations in Japanese patients with Miyoshi myopathy (MM). BACKGROUND: MM is an autosomal recessive distal muscular dystrophy that arises from mutations in the dysferlin gene. This gene is also mutated in families with limb girdle muscular dystrophy 2B. METHODS: The authors examined 25 Japanese patients with MM. Genomic DNA was extracted from the peripheral lymphocytes of the patients. The PCR products of each of 55 exons were screened by single strand conformation polymorphism or direct sequencing from the PCR fragments. RESULTS: The authors identified 16 different mutations in 20 patients with MM; 10 were novel. Mutations in Japanese patients are distributed along the entire length of the gene. CONCLUSIONS: Four mutations (C1939G, G3370T, 3746delG, and 4870delT) are relatively more prevalent in this population, accounting for 60% of the mutations in this study. This study revealed that the G3370T mutation was associated with milder forms of MM and the G3510A mutation was associated with a more severe form.

Adult↗

PubMed2003

Identification of the region in Escherichia coli DnaA protein required for specific recognition of the DnaA box.

DnaA protein binds specifically to a 9-base- pair motif called the DnaA box. Domain IV comprises 94 amino acid residues and is required for DNA binding. Using nuclear magnetic resonance analysis, we investigated the interaction between DnaA domain IV and both a DnaA box and a non-specific oligonucleotide that has a reduced affinity for DnaA. The 1H-15N HSQC spectrum of DnaA domain IV showed prominent chemical shift perturbations on six residues (Arg399, Ala404, Leu422, Asp433, Thr435 and Thr436) in the presence of the DnaA box. Through homology modeling, we located all of these residues on one side surface of the DnaA domain IV molecule. Moreover, we compared the chemical shift perturbation of the 1H-15N HSQC spectrum in the presence of the DnaA box with that in the presence of a non-specific oligonucleotide, and the results suggested that Leu422 imparts specificity in binding with the DnaA box.

Amino Acid Sequence↗

PubMed2003

Bonding efficacy of polyalkenoic acids to hydroxyapatite, enamel and dentin.

Previously, we introduced a methodology to determine the chemical bonding potential of polyalkenoic acids to mineralized tissues through quantification of the degree of ionic bond formation between the carboxyl groups of a polyalkenoic acid with calcium of hydroxyapatite. In a continuation of that study, we now investigated in how far the chemical bonding potential to synthetic hydroxyapatite is influenced by the molecular structure of the polyalkenoic acid and if this also may affect the self-adhesiveness to enamel and dentin. X-ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectrometry were used to quantitatively analyze the chemical bonding efficacy of a polyalkenoic acid consisting of acrylic acid units (PAA) to synthetic hydroxyapatite (HAp) in comparison to the chemical bonding potential of the previously investigated synthesized polyalkenoic acid (s-PA) co-polymer consisting of 90w/w% acrylic and 10w/w% maleic acid units. In addition, the analysis was carried out for enamel and dentin samples. PAA revealed a significantly lower bonding effectiveness with only half of its carboxyl groups bonded to HAp versus about two-third of the carboxyl groups of s-PA. The difference in bonding potential was confirmed by the considerably lower adhesiveness of PAA to enamel and dentin as compared to that of s-PA The present findings indicate that the molecular structure of the polyalkenoic acid significantly influences the chemical bonding efficacy to Hap-based substrates.

Acrylic Resins↗

PubMed2003

Acid pretreatment of titanium implants.

The purpose of this study was to evaluate the effectiveness of several methods of cleaning titanium surfaces as pretreatment for surface modifications by analyzing the chemical interaction of three acids, such as Na(2)S(2)O(8),H(2)SO(4) and HCl, followed by rinsing with acetone or ultrapure water. Chemical evaluation, using X-ray photoelectron spectroscopy (XPS), and mechanical evaluation, using nanoindentation, were employed. XPS revealed that an untreated Ti surface consisted of carbon- and nitrogen-containing contaminant and titanium oxide layer on metallic titanium substrate. The method involving the combination of 10 N HCl and acetone was the most effective of all the methods investigated. Such a combination most effectively reduced values of contamination parameters C/Ti and N/Ti, as well as the intensity of the titanium oxide component in Ti 2p spectra. Chlorine was barely detected from the surface treated with HCl in any concentration. Sulfur from the residual S(2)O(8)(2-) or SO(4)(2-), however, was detected from the samples treated with either Na(2)S(2)O(8) or H(2)SO(4). The S/Ti values depended on concentration of the acidic solution. In addition, nanoindentation measurements revealed that Young's modulus of the surface treated with 0.1-10 N HCl was not significantly different from that of an untreated surface (p > 0.05). Consequently, the HCl/acetone treatment is proposed as an excellent decontamination method for the surface preparation process of Ti.

Acids↗

PubMed2003

Action of FGMgCO3Ap-collagen composite in promoting bone formation.

To improve the biological properties of materials as bone substitutes, functionally graded CO3 apatite crystals containing magnesium, FGMgCO3Ap, were synthesized to be mixed with atelocollagen and made into a composite pellet. A radio-labeled cell adhesion experiment showed that the degree of adherence of mouse MC3T3E1 osteoblast-like cells to the FGMgCO3Ap-collagen composite was better than to CO3Ap-collagen and much better than to the Ti plate. When the composites were implanted beneath the periosteum cranii of rats, the FGMgCO3Ap-collagen composite was metabolized faster than the CO3Ap-collagen composite and better formation of new bone and osteoblast arrangement at the interface between the composite and the periosteum cranii was observed. When the composites were implanted into the femur of rabbits, clear bone formation with a higher degree of bone density was observed for the FGMgCO3Ap-collagen composite. These results suggest that the Mg2+ ions taken into the apatite crystals may contribute to the acceleration of osteoblast adhesion to apatites and promote bone formation, cross-talking with osteoblasts at the molecular level.

3-Hydroxysteroid Dehydrogenases↗

PubMed2003

Evaluation of the skin sensitization potential of chemicals using expression of co-stimulatory molecules, CD54 and CD86, on the naive THP-1 cell line.

It has been known that dendritic cells (DCs) including Langerhans cells (LCs) play a critical role in the skin sensitization process. Many attempts have been made to develop in vitro sensitization tests that employ DCs derived from peripheral blood mononuclear cells (PBMC-DC) or CD34+ hematopoietic progenitor cells (CD34+ HPC) purified from cord blood or bone marrow. However, the use of the DCs in in vitro methods has been difficult due to the nature of these cells such as low levels in the source and/or donor-to-donor variability. In our studies, we employed the human monocytic leukemia cell line, THP-1, in order to avoid some of these difficulties. At the start, we examined whether treatment of the cells with various cytokines could produce DCs from THP-1. Treatment of THP-1 cells with cytokines such as GM-CSF, IL-4, TNF-alpha, and/or PMA did induce some phenotypic changes in THP-1 cells that were characteristic of DCs. Subsequently, responses to a known sensitizer, dinitrochlorobenzene (DNCB), and a non-sensitizer, dimethyl sulfoxide (DMSO) or sodium lauryl sulfate (SLS), on the expression of co-stimulatory molecules, CD54 and CD86, were examined between the naive cells and the cytokine-treated cells. Interestingly, the naive THP-1 cells responded only to DNCB and the response to the sensitizer was more distinct than cytokine-treated THP-1 cells. Similar phenomena were also observed in the human myeloid leukemia cell line, KG-1. Furthermore, with treatment of DNCB, naive THP-1 cells showed augmented expression of HLA, CD80 and secretion of IL-1 beta. The response of THP-1 cells to a sensitizer was similar to that of LCs/DCs. Upon demonstrating the differentiation of monocyte cells in our system, we then evaluated a series of chemicals, including known sensitizers and non-sensitizers, for their potential to augment CD54 and CD86 expression on naive THP-1 cells. Indeed, known sensitizers such as PPD and 2-MBT significantly augmented CD54 and CD86 expression in a dose-dependent manner while non-sensitizers, such as SLS and methyl salicylate (MS), did not. To note, the metal allergens such as (NH(4))(2)[PtCl(4)], NiSO(4) and CoSO(4) augmented significantly only CD54 expression. Taking advantage of a cultured cell line, measurement of the co-stimulatory molecules, CD54 and CD86, on naive THP-1 cells following chemical exposure shows promise for the development of a simple, short-term in vitro sensitization test.

Antigens, CD↗

PubMed2003

Distribution of Actinobacillus actinomycetemcomitans serotypes and Porphyromonas gingivalis in Japanese adults.

Strains of the bacterium Actinobacillus actinomycetemcomitans found in the human oral cavity are divided into five serotypes, a, b, c, d, and e. In this study, A. actinomycetemcomitans serotypes and Porphyromonas gingivalis were isolated from 656 subgingival sites in systemically healthy Japanese adults. A. actinomycetemcomitans was detected in 19.5% of 328 Japanese subjects, while 27.1% of subjects were positive for P. gingivalis. Of 75 A. actinomycetemcomitans-positive sites, only one serotype was detected in 39 sites (52.0%). The numbers of sites in which two different serotypes and three different serotypes were detected were 18 (25.0%) and 7 (9.3%), respectively. A. actinomycetemcomitans serotype c was detected more frequently in sites that were positive for both P. gingivalis and A. actinomycetemcomitans (76.9%) than in sites that were P. gingivalis-negative and A. actinomycetemcomitans-positive (33.9%). In addition, serotype c was detected much more frequently than the other serotypes (<16%) in sites that were positive for both P. gingivalis and A. actinomycetemcomitans. These findings suggest that the characteristics of serotype c may differ from those of the other serotypes. This report is the first to use PCR to describe the distribution of A. actinomycetemcomitans serotypes in humans and to examine the association between the distribution of A. actinomycetemcomitans serotypes and the presence of P. gingivalis.

Adult↗

PubMed2003

FK506-associated limbic injury following umbilical cord blood transplantation.

A 5-year-old girl with Ph-positive chronic myelogenous leukemia, who underwent umbilical cord blood transplantation, developed two episodes of electrical status epilepticus while receiving tacrolimus (FK506) then cyclosporin A (CsA), as treatment against graft-versus-host disease. MRI including diffusion weighted MR imaging of the brain revealed abnormalities in the hippocampus and posterior white matter following FK506 and CsA treatment, respectively. While posterior white matter injury has been described with both FK506 and CsA, no previous report describes hippocampal injury from either drug. The MRI changes in the hippocampus in our case suggest possible increased susceptibility to hippocampal injury with FK506.

Child, Preschool↗

PubMed2003

Effect of rebamipide on prostaglandin receptors-mediated increase of inflammatory cytokine production by macrophages.

BACKGROUND: Rebamipide (Reb) is an anti-ulcer drug, and has unique properties such as anti-inflammatory action. We previously reported that prostaglandins (PGs) dramatically increased vascular endothelial growth factor (VEGF), a known angiogenic factor and a vascular permeable factor, by activated macrophages through specific PGE receptor and peroxisome proliferator-activated receptor gamma (PPARgamma, a nuclear receptor of PG) mediated process. Effects of PGs on the production of other cytokines such as interleukin (IL)-6 and IL-8 have been controversial. AIM: To clarify the anti-inflammatory roles of Reb, we examined the effect of Reb on PGE1- and 15-deoxy-Delta12, 14-PGJ2 (a potent PPARgamma ligand, 15d-PGJ2) -induced increase of VEGF production by macrophages. Additionally, effects of these PGs on the production of IL-6 and IL-8, and modulation of these actions by Reb were studied. METHODS: Phorbol 12-myristate 13-acetate-differentiated U937 cells were used as a human macrophage model (H-Mac). VEGF, IL-6, IL-8 and cAMP were measured by EIA. RESULTS: Reb suppressed PGE1-, but not 15d-PGJ2-, induced increase of VEGF production partially through decrease of cAMP formation. Reb suppressed PGE1 -, but not 15d-PGJ2-, induced increase of IL-6 and IL-8 production. CONCLUSION: Reb suppresses membrane, but not nuclear PG receptors mediated increase of inflammatory cytokine production, which may be involved in anti-ulcer action of this drug.

Alanine↗

PubMed2003

The effect of rebamipide on Helicobacter pylori extract-mediated changes of gene expression in gastric epithelial cells.

BACKGROUND: Recent studies have shown that Helicobacter pylori affects intracellular signal transduction in host cells, leading to the activation of transcriptional factors and the induction of pro-inflammatory cytokines. On the other hand, rebamipide, an anti-gastritis and anti-ulcer agent, could scavenge reactive oxygen species and reduce interleukin-8 (IL-8) expression in gastric epithelial cells induced by H. pylori-stimulation through the attenuated activation of nuclear factor-kappaB (NF-kappaB). AIMS: In this study, we investigated the effects of rebamipide on gene expression in H. pylori-stimulated epithelial cells using DNA chip. METHODS: H. pylori water extract (HPE) was prepared from NCTC11637, the type strain of H. pylori. Total RNA was extracted from MKN45 cells, a human gastric cancer cell line, following HPE-stimulation with and without rebamipide for 3 h, and differences in gene expression profiles were observed using GeneChip and Human 6800 probe array. RESULTS: The GeneChip analysis demonstrated that 132 up-regulated genes and 873 down-regulated genes, such as growth factors, chemokines and transcription factors, were detected in MKN45 cells 3 h after stimulation of H. pylori. Among them, several genes, including bFGF, RANTES and MIP-2beta, were previously unknown to be expressed in H. pylori-stimulated human gastric cells. Rebamipide reduced expression of 119 genes encoding cytokines, growth factors and their receptors and transcription factors. CONCLUSIONS: These findings suggest that rebamipide could inhibit inflammatory reactions and tumour progression by modifying H. pylori infection-induced gene expression in gastric epithelial cells.

Alanine↗

PubMed2003

A novel tumour marker RCAS1 in a case of extramammary Paget's disease.

A 66-year-old male, whose primary skin lesion in extramammary Paget's disease had been surgically resected 4 years previously, was hospitalized with liver metastases. Hepatic arterial infusion chemotherapy was carried out and the tumours clearly reduced in size. Serum levels of some common tumour markers were not elevated, even prior to therapy. We measured serum levels of a novel tumour-associated antigen, RCAS1, because its expression was detected in the tumour cells. The patient's serum RCAS1 level was elevated (22.0 U/mL) before therapy and fell during (10.5 U/mL) and after (5.0 U/mL) therapy. Therefore, serum RCAS1 levels may be valuable as a potential biomarker for monitoring therapeutic efficacy against Paget's disease.

Aged↗

PubMed2003

Do Japanese and Swedish peptic ulcer patients respond differently to Helicobacter pylori eradication therapies and what are their histological features?

BACKGROUND: As a consequence of gastric histological differences, Japanese and Swedish peptic ulcer (PU) patients may respond differently to Helicobacter pylori eradication therapies. METHODS: The study was single-blind and compared four eradication therapies in Japanese and Swedish patients with healed gastric (GU) or duodenal (DU) ulcer. Swedish patients received either (a) omeprazole+clarithromycin (OC, where O = 20 mg, C = 500 mg) for 2 weeks, or triple therapy with (b) omeprazole + amoxicillin + clarithromycin (OAC-L where O = 20mg, A = 1 g, C = 250 mg); (c) OAC-H (where O = 20 mg, A-1 g, C-500 mg); or (d) omeprazole + metronidazole + clarithromycin (OMC, where O = 20 mg, M = 400 mg, C = 250 mg) for 1 week. Antibiotic doses were weight-adjusted downwards in Japanese patients. H. pylori was assessed using the urea breath test (UBT), histology and culture pre-entry, with UBT being repeated 4 and 8 weeks after stopping treatment. Histology and culture were repeated if the UBT was positive post-therapy. RESULTS: Recruitment included 120 patients from Japan (43 GU, 61 DU, 16 GU+DU) and 120 from Sweden (119 DU, 1 GU+DU). There were 26 exclusions from a FAS analysis due to H. pylori negativity (14), no drug administration (7) or no data after visit 1 (5). Eradication rates (FAS) from Japan were (a) 63%, (b) 93%, (c) 96% or (d) 96%, and for Sweden (a) 92%, (b) 86%, (c) 93% or (d) 96%. Dual therapy was less effective in patients with gastric atrophy associated with GU disease. Tolerability was good in all treatment groups, with no serious adverse events. CONCLUSION: Triple therapies were safe and effective for H. pylori eradication in Japanese and Swedish peptic ulcer patients. Dual therapy was significantly less effective in the Japanese patients, half of whom had a history of GU and more abnormal histology than in the Swedish patients, all of whom had DU.

Adult↗

PubMed2003

Basal cell carcinomas in association with basaloid follicular hamartoma.

We describe a unique case of various types of basal cell carcinoma (BCC) associated with basaloid follicular hamartoma (BFH) in a 56-year-old female patient. The lesion consisted of a dark brown and elastic soft nodule and papules within the area of a birthmark on the neck. The lesion was surgically excised. Histological examination of the nodular region revealed aggregations of neoplastic basaloid cells. We diagnosed the nodule as BCC with a racemiform or reticular pattern. In addition, a specimen taken from brownish black papules within the birthmark was found to be composed of anastomosing cords of basaloid cells accompanied by infundibular cystic structures. These features were consistent with an infundibulocystic BCC. In contrast, specimens from a hamartomatous plaque showed distinctive branching strands of basaloid cells that are suggestive of BFH. Therefore, our findings indicate that several types of BCC may develop within a BFH.

Adult↗