Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 55 records · Page 3Linked to original sources

PubMed2003

A novel technique to evaluate the adhesion of Candida species to gingival epithelial cells.

We developed an in vitro ATP assay technique to extract cellular and fungal ATP separately, which allowed to evaluate quantitatively the adhesion of the yeasts to monolayers of human gingival epithelial cells. Thirteen isolates of Candida spp. representing three species (i.e. Candida albicans, C. tropicalis and C. glabrata) were used in the present study. When the adherent capacity of the Candida species was compared, C. albicans exhibited highest capacity of adherence to gingival epithelial cells, followed by C. tropicalis, and C. glabrata was the lowest [analysis of variance (ANOVA), P < 0.01]. The germ tubes of C. albicans exhibited significantly higher adherence capacity than their blastoconidia cells (ANOVA, P < 0.01), which was not observed with a C. albicans isolate, defect of germ tube formation. Our results suggested that the adherence of C. albicans is promoted by germ tube formation and may play an important role in the pathogenesis of the fungus.

Adenosine Triphosphate↗

PubMed2003

Interaction of fibre type, potentiation and fatigue in human knee extensor muscles.

AIM: To examine the effect of fibre type on potentiation and fatigue. METHODS: Young men (n = 4 per group) with a predominance of type I [61.4 +/- 6.9% (SD), group I (GI)] or type II [71.8 +/- 9.2%, group II (GII)] fibres in vastus lateralis, performed a fatigue protocol of sixteen 5-s maximal voluntary isometric contractions (MVCs) of the right knee extensors. Maximal twitches and corresponding muscle action potentials (M-waves) were evoked before the first MVC, during the 3-s rest period after each MVC and at intervals during the 5-min recovery period after the last MVC. RESULTS: Group II [49.3 +/- 2.6% (SE)] had a greater decrease in MVC force than GI (22.8 +/- 6.2%) during the fatigue protocol. Group II (126.4 +/- 13.6%) showed greater twitch force potentiation early in the fatigue protocol than GI (38.2 +/- 2.3%), but greater depression at the end (33.7 +/- 13.7% vs.17.4 +/- 3.4%). Twitch time-to-peak torque (TPT) and half relaxation time (HRT) initially decreased but then increased as the fatigue protocol progressed; GII had a greater increase in HRT. During a 5-min recovery period twitch force increased above the prefatigue level and remained so until the end of the recovery period; the pattern was similar in GI and GII. Twitch TPT and HRT remained elevated during recovery. M-wave area increased throughout the fatigue protocol and the first part of recovery before returning to baseline values in GII, whereas there were no significant changes in GI. The interaction between potentiation and fatigue was amplified in GII early in the fatigue protocol with concurrently greater twitch and M-wave potentiation, and greater MVC force decrease and HRT increase. Late in the protocol, GII had a greater decrease in twitch and MVC force combined with greater M-wave potentiation. CONCLUSION: It is concluded that fibre type distribution influences potentiation and fatigue of the twitch, and potentiation of the M-wave during fatiguing exercise.

Action Potentials↗

PubMed2003

Confocal laser scanning microscopic observation of glycocalyx production by Staphylococcus aureus in skin lesions of bullous impetigo, atopic dermatitis and pemphigus foliaceus.

BACKGROUND: Glycocalyx collapses during dehydration to produce electron-dense accretions. Confocal laser scanning microscopy (CLSM) may be used to visualize fully hydrated microbial biofilms. OBJECTIVES: Using CLSM, to analyse glycocalyx production by Staphylococcus aureus cells in skin lesions of bullous impetigo, atopic dermatitis and pemphigus foliaceus. A second objective was to compare numbers of S. aureus cells in tissue sections prepared by different methods for routine light microscopy. METHODS: S. aureus cells in skin lesions of impetigo, atopic dermatitis and pemphigus were stained with safranin, and positive staining with fluorescein isothiocyanate-conjugated concanavalin A was considered to indicate the presence of glycocalyx. RESULTS: All S. aureus cells tested in skin lesions of impetigo, atopic dermatitis and pemphigus were covered with glycocalyx and formed microcolonies. The numbers of S. aureus cells in a routine light microscopy section were significantly lower than those in a frozen section that had not been dehydrated with ethanol. CONCLUSIONS: S. aureus cells generally produce glycocalyx in skin lesions of bullous impetigo, atopic dermatitis and pemphigus foliaceus, which accounts for the difficulty of removing S. aureus cells from these skin lesions. The glycocalyx may collapse during dehydration and most of the S. aureus cells may be carried away during preparation of routine light microscope sections.

Acetic Acid↗

PubMed2003

Molecular basis of lipoid proteinosis in a Libyan family.

Lipoid proteinosis is an autosomal recessive condition associated with variable scarring and infiltration of skin and mucosae. The disorder has recently been shown to result from loss-of-function mutations in the extracellular matrix protein 1 gene (ECM1) on 1q21. Extracellular matrix protein 1 has important physiological and biological roles in aspects of epidermal differentiation, binding of dermal collagens and proteoglycans, and in regulation of angiogenesis. Thus far pathogenic mutations have been described in 16 different families with lipoid proteinosis throughout the world. In this report, we describe the clinico-pathological features of a 10-year-old boy with lipoid proteinosis from a consanguineous Libyan family. By direct sequencing of the affected individual's genomic DNA, we identified a homozygous nonsense mutation in exon 2 of the ECM1 gene, Q32X. This mutation is the most 5' of all ECM1 mutations described thus far and is predicted to ablate the ECM1a, ECM1b and ECM1c splice variants of the ECM1 gene and to result in a severe clinical phenotype. Sequencing of DNA from the affected individual's five siblings revealed that four were heterozygous carriers of Q32X, findings that have important implications for genetic counselling given the high frequency of consanguineous marriages in Libya.

Child↗

PubMed2003

Changes in surface roughness and colour stability of soft denture lining materials caused by denture cleansers.

Soft denture lining materials were immersed into solutions of denture cleansers for 8 h at room temperature, and immersed into distilled water for the remainder of the 24-h period at 37 degrees C. Surface roughness of the soft denture lining materials was measured by contact type surface roughness instrument. For the colour stability test, soft denture lining materials were immersed in the denture cleansers as described above for 180 days. Finally, the colour changes of each material were quantitatively measured by a photometrical instrument to obtain the colour differences between newly processed specimen and immersed specimens (P < 0.01). An autopolymerizing silicone material, Evatouch, exhibited severe changes in surface roughness by all denture cleanser, and the generic material GC Denture Relining showed the minimal changes. Severe colour changes were also observed with some liner and cleanser combinations (P < 0.01). Except for Evatouth, the four silicone soft liners were more stable in surface roughness and in colour change than the two acrylic soft liners. One autopolymerizing silicone (GC denture relining) and one heat curing silicone (Molloplast B) demonstrated the best stability.

Color↗

PubMed2003

Biofilm formation of Candida albicans on the surfaces of deteriorated soft denture lining materials caused by denture cleansers in vitro.

Candidal colonization and subsequent biofilm formation on denture materials are important in the development of pathogenesis, such as denture stomatitis. Routine use of denture cleansers is one of the most effective methods of denture plaque control, although the incompatibility of soft liners and denture cleansers cause damage to the materials. The present study, biofilm formation of Candida albicans on the surfaces of soft denture lining materials, immersed in denture cleansers for 180 days were studied. Seven commercially available soft denture lining materials, were artificially deteriorated by immersion into three commercially available denture cleansers for 180 days, and subsequent fungal growth and biofilm formation were studied by measuring pH of the media and by the use of adenosine triphosphate (ATP) analysis. Fungal biofilm formation on the deteriorated soft liners varied depending upon the combination of the soft liners and denture cleansers. Several combinations of soft liners with denture cleansers exhibited the significantly high colonization capacity as compared with each sample immersed in distilled water, used as individual controls. The relationship between the biofilm formation on the samples of each material and the surface roughness of the soft lining materials was analyzed. However, no significant correlation was observed. The results, taken together, suggested that fungal colonization could be predominantly regulated by the combination of lining material with denture cleansers. In clinical terms, our findings suggests that daily cleansing of soft lining materials with mismatched denture cleansers promoted the subsequent biofilm formation of fungi on the materials.

Biofilms↗

PubMed2003

Correlation between maximum bite force and craniofacial morphology of young adults in Indonesia.

The present study was conducted to evaluate the relationship between maximum bite force and craniofacial morphology. Sixty-four Indonesian female dental students aged 19-27 years with normal occlusion served as the subjects. The Dental Prescale System was used to measure the maximum bite force using a pressure sensitive sheets while craniofacial morphology measurements were determined from conventional lateral radiograms. The antero-posterior and right-left position of the occlusal load centre (the OLC) were measured also. Stepwise multiple regression analysis was performed to evaluate the relationship between bite force and craniofacial morphology while correlation analysis was used to evaluate the antero-posterior position of the OLC related to craniofacial morphology. Fifty-five per cent of the bite force could be explained by variations in the posterior facial height, gonial angle, antero-posterior size of the maxilla, and posterior length of the cranial base. The result showed a larger bite force implies a greater posterior facial height, smaller gonial angle, larger maxilla and straighter posterior length of the cranial base. This study suggests that among Indonesians, maximum bite force could be explained by craniofacial morphology as found in Caucasians. In addition, we proposed a clinical standard of the OLC for the comprehensive evaluation of occlusion.

Adult↗

PubMed2003

Analyses of absorbed dose to tooth enamel against external photon exposure.

Absorbed dose to tooth enamel was examined against external photon exposure by measurements with thermoluminescence dosemeters (TLDs) and Monte Carlo calculations. TLDs were placed in a realistic physical phantom to measure dose to the teeth region in a head. A voxel-type phantom was constructed from computed tomography (CT) images of the physical phantom. Monte Carlo calculations with this voxel-type phantom were performed to analyse the results of the experiments. The data obtained were compared to the enamel doses, which were calculated with a modified MIRD-type phantom and already given in a previous paper. It was confirmed that the data derived with the MIRD-type phantom are applicable for retrospective individual dose assessments by electron spin resonance (ESR) dosimetry using teeth for the photon energy region above 300 keV. The analysis, however, indicated that the configuration of the head can affect the enamel dose relative to external exposure to photons with energy below 100 keV.

Calibration↗

PubMed2003

Squamous metaplasia induced by transfection of human papillomavirus DNA into cultured adenocarcinoma cells.

BACKGROUND/AIM: It has been reported previously in cases of adenosquamous carcinoma of the lung in Okinawa, a subtropical island 2000 km south of mainland Japan, that the squamous cell carcinoma components were positive for human papillomavirus (HPV) by non-isotopic in situ hybridisation (NISH). The adenocarcinoma cells adjacent to the squamous cell carcinoma components were enlarged and also positive for HPV. This is thought to indicate that after adenocarcinoma cells are infected with HPV, they undergo morphological changes, and that "squamous metaplasia" follows. In this present study, the effects of HPV transfection into adenocarcinoma cells were examined. The relation between the region expressing the HPV gene and squamous metaplasia was also studied. METHODS: Plasmid pBR322 containing HPV type 16 (HPV-16) was transfected into cultured colonic adenocarcinoma (DLD-1) and lung adenocarcinoma (PC-14) cells using the calcium phosphate method. Neomycin was used as a selection marker. The presence of HPV E1, E2, E4, E5, E6, E7, L1, and L2 mRNAs and also transglutaminase 1, involucrin, cyclin dependent kinases (CDKs), cyclins, caspases, apoptosis inducing factor, DNase gamma, Fas, and Fas ligand mRNAs in HPV transfected cells was investigated by means of reverse transcription polymerase chain reaction (RT-PCR). The G0-G1 cell population was analysed by flow cytometry. Morphological examination under light and electron microscopes was also carried out. RESULTS: The virus transfected cells showed squamous metaplasia when they were injected into severe combined immunodeficient mice, expressing the high molecular weight keratin (Moll's number 1 keratin) and involucrin molecules immunohistochemically, and involucrin and transglutaminase I mRNAs by RT-PCR. The squamous metaplasia was most conspicuous in the HPV transfected DLD-1 cell when compared with HPV transfected PC-14 cells. Squamous metaplasia was most clearly demonstrated in one HPV transfected DLD-1 cell clone, which expressed not only E2 but also E6-E7 fusion gene mRNA. Viral L1 mRNA expression was absent in HPV transfected cell clones, and was not related to squamous metaplasia. The growth rate of HPV transfected cells was reduced. Transfection of the virus into the cultured adenocarcinoma cells increased the G0-G1 cell population greatly, as assessed by flow cytometer analysis. Furthermore, in the virus transfected cells, apoptosis was also observed by means of the terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labelling method. CONCLUSION: HPV transfection into adenocarcinoma cells induced clear squamous metaplasia. One of the HPV transfected cell clones that expressed E2 and E6-E7 fusion gene mRNA showed the squamous metaplasia particularly clearly, and apoptosis was also demonstrated.

Adenocarcinoma↗

PubMed2003

Abnormal nocturnal blood pressure fall in senile-onset depression with subcortical silent cerebral infarction.

Recent studies have shown that the complication rate of silent cerebral infarction (SCI) in patients with geriatric depression increases with the age at the onset of depression. This study investigated the cardiovascular factors involved in the development of SCI in geriatric depression. Thirty-six patients with geriatric depression were classified according to the age at onset into 16 who developed depression at the age of <50 years (early-onset group) and 20 who developed depression at the age of > or =50 years (late-onset group). The incidence of SCI assessed by subcortical hyperintensity on MRI images, office blood pressure (BP), nocturnal systolic BP fall pattern examined by 24-hour ambulatory BP monitoring, and the severity of carotid atherosclerosis examined by B-mode ultrasonography were compared between the two groups. Furthermore, the association between the presence or absence of SCI and the nocturnal systolic BP fall pattern or the severity of carotid atherosclerosis was evaluated. The SCI complication rate was higher in the late-onset group (55.0%) than in the early-onset group (18.7%). The office BP and mean 24-hour BP did not differ significantly between the two groups. Abnormal nocturnal systolic BP fall patterns were observed in 85.0% (nondipper type showing a fall of <10% in 60.0%, extreme-dipper type showing a fall of > or =20% in 25.0%) in the late-onset group, which was significantly higher than the incidence in the early-onset group (18.7%). No significant difference was observed in any parameter of carotid atherosclerosis between the two groups. In addition, the patients with SCI more frequently showed abnormal nocturnal systolic BP fall patterns than those without SCI. These results suggest that abnormal nocturnal BP fall patterns appear to be involved in the development of SCI in senile-onset depression.

Age of Onset↗

PubMed2003

Dynamic shear properties of the temporomandibular joint disc.

Shear stress might be an important factor associated with fatigue failure and damage of the temporomandibular joint disc. Little information, however, is available on the dynamic behavior of the disc in shear. Since the disc is an anisotropic and viscoelastic structure, in the present study the dependency of the dynamic shear behavior on the direction and frequency of loading was examined. Ten porcine discs were used for dynamic shear tests. Shear stress was applied in both anteroposterior (A-P test) and mediolateral (M-L test) directions. The dynamic moduli increased as the loading frequency increased. The dynamic elasticity was significantly larger in the A-P test than in the M-L test, although the dynamic viscosity was similar in both tests. The present results suggest that non-linearities, compression/shear coupling, and intrinsic viscoelasticity affect the shear material behavior of the disc, which might have important implications for the transmission of load in the temporomandibular joint.

Animals↗

PubMed2003

Heterozygous mutation in the SAM domain of p63 underlies Rapp-Hodgkin ectodermal dysplasia.

Several ectodermal dysplasia syndromes, including Ectrodactyly-Ectodermal dysplasia-Clefting (EEC) and Ankyloblepharon-Ectodermal Dysplasia-Clefting (AEC) syndromes, are known to result from mutations in the p63 gene. We investigated whether Rapp-Hodgkin syndrome (RHS) is also caused by mutations in the p63 gene. We identified a heterozygous de novo germline missense mutation, S545P, in the sterile-alpha-motif (SAM) domain of p63, in a Thai patient affected with RHS. This is the first genetic abnormality to be described in RHS. The amino acid substitution is the most downstream missense mutation in p63 reported thus far. Histological assessment of a skin biopsy from the patient's palm showed hyperkeratosis and keratinocyte cell-cell detachment in the upper layers of the epidermis, along with numerous apoptotic keratinocytes. Collectively, these investigations demonstrate that RHS is also caused by mutations in p63 and that the clinical similarities to AEC syndrome are paralleled by the nature of the inherent mutation.

Adolescent↗

PubMed2002

Genotype-phenotype correlation in skin fragility-ectodermal dysplasia syndrome resulting from mutations in plakophilin 1.

We report a 42-year-old Japanese man with an unusual autosomal recessive genodermatosis. The clinical features comprised normal skin at birth, loss of scalp hair at 3-months of age after a febrile illness, progressive nail dystrophy during infancy, palmoplantar keratoderma starting around the age of 18 years and trauma-induced skin fragility and blisters noted from the age of 20 years. Skin biopsy of rubbed non-lesional skin revealed widening of spaces between adjacent keratinocytes from the suprabasal layer upwards. Electron microscopy demonstrated a reduced number of hypoplastic desmosomes. Immunohistochemical labeling showed a reduction in intercellular staining for the desmosome component plakophilin 1. Mutation analysis revealed a homozygous intron 11 donor splice site mutation in the plakophilin 1 gene, 2021+1 G>A (GenBank no. Z34974). RT-PCR, using RNA extracted from the skin biopsy, provided evidence for residual low levels of the full-length wild-type transcript (approximately 8%) as well as multiple other near full-length transcripts, one of which was in frame leading to deletion of 17 amino acids from the 9th arm-repeat unit of the plakophilin 1 tail domain. Thus, the molecular findings help explain the clinical features in the patient, who has a similar but milder phenotype to previously reported patients with skin fragility-ectodermal dysplasia syndrome associated with complete ablation of plakophilin 1 (OMIM 604536). This new 'mitis' phenotype provides further clinicopathological evidence for the role of plakophilin 1 in keratinocyte cell-cell adhesion and ectodermal development.

Adult↗

PubMed2002

Differences in Candida albicans adhesion to intact and denatured type I collagen in vitro.

An inhibition assay of Candida albicans adhesion to gelatin-immobilized membranes was compared with that to intact type I collagen-immobilized membranes using an arginine-glycine-aspartic acid (RGD) containing peptide. As compared with a protein-free membrane, gelatin and collagen significantly enhanced the adherence of C. albicans. The adhesion of the yeast to gelatin was significantly inhibited by the RGD peptides, but not by arginine-glycine-glutamic acid (RGE) peptides. In contrast, attachment to collagen was not inhibited by RGD peptides. These results suggest that the RGD sequence of gelatin and the integrin-like proteins of yeasts may be involved in adherence.

Adhesiveness↗

PubMed2002

EEC (Ectrodactyly, Ectodermal dysplasia, Clefting) syndrome: heterozygous mutation in the p63 gene (R279H) and DNA-based prenatal diagnosis.

BACKGROUND: Germline mis-sense mutations in the DNA-binding domain of the p63 gene have recently been established as the molecular basis for the autosomal dominant EEC (Ectrodactyly, Ectodermal dysplasia, Clefting) syndrome. OBJECTIVES: To examine genomic DNA from a 36-year-old woman, her 58-year-old father and her 11-year-old son, all with the EEC syndrome, to determine the inherent p63 mutation and, after genetic counselling, to use knowledge of the mutation to undertake a first-trimester DNA-based prenatal diagnosis in a subsequent pregnancy. METHODS: Fetal DNA was extracted from chorionic villi and used to amplify exon 7 of p63 containing the potential mutation. Direct sequencing and restriction endonuclease digestion (loss of AciI site on mutant allele) were used for DNA-based prenatal diagnosis. RESULTS: We identified a heterozygous arginine to histidine p63 mutation, R279H, in all three affected individuals. Prenatal diagnosis demonstrated a homozygous wild-type sequence predicting an unaffected child: a healthy boy was subsequently born at full-term. CONCLUSIONS: These data expand the p63 gene mutation database and provide the first example of a DNA-based prenatal test in this ectodermal dysplasia syndrome.

Abnormalities, Multiple↗

PubMed2002

An immunohistochemical and ultrastructural study of syringocystadenoma papilliferum.

BACKGROUND: Syringocystadenoma papilliferum is a benign hamartomatous tumour of the skin. The histogenesis of this tumour is still controversial. There have been few reports regarding immunohistochemical investigations using only a limited range of antibodies and ultrastructural studies on this rare tumour. OBJECTIVES: To elucidate the immunohistochemical and ultrastructural properties of this tumour. METHODS: We investigated the immunohistological patterns of 12 different anticytokeratin (CK) antibodies and several other markers in five cases of this tumour, comparing them with the patterns in adult sweat glands. One of these cases was also evaluated ultrastructurally. RESULTS: The luminal columnar cells of the tumour were mostly positive for CK7 and more than 70% were positive for CK19. These cells showed the heterogeneous expression of CK1/5/10/14, CK14 and CK5/8. These patterns were also observed in the luminal cells in the secretory or the ductal portion of the adult sweat glands. The basal cuboidal cells of the tumour almost constantly expressed CK1/5/10/14, CK5/8, CK14 and CK7 (except for one case), similar to the patterns of basal cells in the transitional portion and myoepithelial cells in the sweat glands. However, the basal tumour cells expressed CK19 and vimentin heterogeneously, and alpha-smooth muscle actin focally (three cases). Ultrastructurally, the constituent epithelial cells were mainly divided into three types: luminal cells, basal cells and clear cells. The luminal tumour cells bore features of the secretory or ductal luminal cells of sweat glands, although they were somewhat immature in appearance. The basal tumour cells were fundamentally basaloid in nature. The clear cells were undifferentiated or primitive in appearance, suggesting stem or progenitor cell properties. Transitional forms between the clear cells and the other two cell types were also identified. CONCLUSIONS: The tumour epithelium was composed of several cell types demonstrating various developmental stages from the primitive clear cells to the basal cells demonstrating a tendency to differentiate toward basal cells in the apocrine transitional portion or myoepithelial lineage, or luminal cells toward the ductal or secretory epithelium. These results support the classical concept that syringocystadenoma papilliferum is a hamartomatous tumour that arises from pluripotent cells.

Adenoma, Sweat Gland↗

PubMed2002

Lipoid proteinosis.

Lipoid proteinosis is a rare, autosomal recessive disorder that presents in early infancy with hoarseness, followed by pox-like and acneiform scars, along with infiltration and thickening of the skin and certain mucous membranes. Histological and ultrastructural examination reveals widespread deposition of hyaline-like material and disruption/reduplication of basement membrane around blood vessels and at the dermal--epidermal junction. Recently, lipoid proteinosis was mapped to 1q21 and pathogenetic loss-of-function mutations were identified in the extracellular matrix protein 1 gene (ECM1). This article reviews the molecular basis of lipoid proteinosis and reassesses the clinico-pathological features of this disorder in light of the new genetic discoveries.

Diagnosis, Differential↗

PubMed2002

A case of POEMS syndrome associated with reactive amyloidosis and Waldenström's macroglobulinaemia.

A72-year-old Japanese man presented with a 5-year history of fatigue, night sweats, oedema of dorsum of foot, muscle weakness, and paresthesia of the lower extremities. On examination, the patient fulfilled the diagnostic criteria for POEMS syndrome, but was unusual in that he also had underling Waldenström's macroglobulinaemia with IgM kappa. The M protein of POEMS syndrome is usually IgG and IgA with lambda light chains. To our knowledge, there are only three cases of POEMS syndrome with IgM kappa including our case. Autopsy findings revealed that small lymphocytes were more prominent than plasma cells in the bone marrow. These plasma cells were stained with IgM kappa. Amyloid deposits identified by Congo red stain were detected predominantly in the vascular walls of the gastrointestinal tract, pancreas and kidney. This amyloid protein was classified as amyloid associated protein. This is the first case of POEMS syndrome associated with reactive amyloidosis and Waldenström's macroglobulinaemiae.

Aged↗