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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 37 records · Page 2Linked to original sources

Results of surgical treatment for non-small cell lung cancer of 20 mm or less in diameter.

BACKGROUND: Surgical efficacy is still unsatisfactory for small lung cancer; accordingly, minimal resection has recently been the focus of increased study. The objective of the current study was to evaluate the factors associated with small lung cancer, and to determine whether such factors are reliable predictors of long-term survival. METHODS: We retrospectively investigated 130 patients with histologically confirmed non-small cell carcinoma, whose treatments were primarily surgical, with no chemotherapy or radiotherapy prior to surgery. All tumors were located peripherally and were less than 20 mm in diameter. Follow-up was performed for five-year and eight-year survivors and multivariate analysis with Cox's proportional hazards regression model was performed. RESULTS: Of all 130 patients, the 5-year survival rate among patients with tumors less than 15 mm was 82.5 %, vs. 57.4 % of patients with tumors with a diameter of 16 - 20 mm. The 5-year survival rate of patients who were node negative was 73.9 % while it was 28.5 % for node-positive patients. Status of nodal invasion was also significantly associated with survival in small-size tumors ( p < 0.0001). Furthermore, the 5-year survival rate among patients with pleural involvement was 55 % vs. 83.8 % for patients without pleural involvement. Using multivariate Cox analysis, lymph node involvement ( p = 0.0004), size ( p = 0.0475), and pleural invasion ( p = 0.0482) were found to be independent prognostic factors in cases of tumors 20 mm or less in diameter. CONCLUSIONS: The results of this study at least demonstrate that the optimal therapy for patients with nodal involvement or patients with tumors of 16 - 20 mm must be carefully determined even in cases of small lung cancer.

Aged↗

Clinical and molecular characterization of lipoid proteinosis in Namaqualand, South Africa.

BACKGROUND: Lipoid proteinosis (LiP) is a rare autosomal recessive disorder characterized by a hoarse voice, warty skin infiltration and scarring. Mutations within the extracellular matrix protein 1 (ECM1) gene cause LiP. Since the early 1970s it has been recognized that South Africa has one of the largest groups of LiP patients worldwide, suggesting a probable founder effect. As LiP patients present with considerable clinical variability, this group of patients offers a unique opportunity for genotype-phenotype correlation. OBJECTIVES: To assess the clinical features and the molecular basis of LiP in patients from the Namaqualand area of the Northern Cape province of South Africa and to examine molecular evidence for a founder effect. SUBJECTS AND METHODS: The LiP patient cohort consisted of 29 Coloured patients from Namaqualand and a further seven Caucasoid patients from other areas of South Africa. The control group included 100 healthy geographically and ethnically matched individuals from Namaqualand. Samples were collected after informed consent and with ethics committee approval from the University of the Witwatersrand. LiP patients were examined clinically and a structured recording sheet was completed. A brief neurological evaluation was also performed. The LiP founder effect was investigated at the molecular level by ECM1 mutation detection and haplotype analysis. RESULTS: The most consistent clinical signs for a diagnosis of LiP in this group were a hoarse voice and thickened sublingual frenulum leading to restricted tongue movement. Homozygosity for a nonsense mutation in exon 7 of the ECM1 gene, Q276X, was identified in all patients (Coloured and Caucasoid). Despite this genetic homogeneity, considerable clinical variability in skin presentation and psychiatric involvement was observed. Haplotype analysis using markers from a 9.98-Mb region around the ECM1 locus confirmed the founder effect with a founder core haplotype, 19-Q276X-12 (ND1-ECM1-D1S2343), in all but four LiP-associated alleles (n = 58). A LiP carrier rate of 1 in 9 was observed among the 100 Namaqualand controls, predicting a LiP incidence of 1 in 324 in this community. CONCLUSIONS: Although several consistent clinical features in LiP patients homozygous for the Q276X mutation in the ECM1 gene were observed, there remains considerable clinical variability. This suggests the action of genetic and environmental modifiers of disease severity. Strong molecular evidence supports a single founder effect for the high prevalence of LiP in South Africans, both Coloured and Caucasoid.

Adolescent↗

Progressive osseous heteroplasia resulting from a new mutation in the GNAS1 gene.

Progressive osseous heteroplasia (OMIM 166350) is a rare autosomal dominant condition that presents in childhood as dermal ossification and may progress deeper to involve subcutaneous fat and connective tissue. Recently, paternally inherited inactivating mutations in the GNAS1 gene on chromosome 20q13 have been implicated in the pathogenesis, although sporadic cases have also been reported. We report a 9-year-old British Chinese girl with progressive osseous heteroplasia resulting from a de novo missense mutation (W281R) in the GNAS1 gene. She is of small stature (0.4th centile) and started to develop skin lesions at the age of 9 months. These have been confirmed histologically as osteoma cutis. She is of normal intelligence and development and has no dysmorphic features. The GNAS1 gene exhibits imprinting and maternally inherited mutations have previously been shown to result in Albright's hereditary osteodystrophy (OMIM 103580) with pseudohypothyroidism type 1a, whereas paternally inherited mutations result in progressive osseous heteroplasia or the Albright's hereditary osteodystrophy phenotype with pseudopseudohypothyroidism (OMIM 300800). With only nine mutations of the GNAS1 gene reported so far in progressive osseous heteroplasia, this new mutation helps to extend further the genotype-phenotype correlation.

Child↗

Physical properties and compatibility with dental stones of current alginate impression materials.

This study examined physical properties and compatibility with dental stones of two types of alginate impression materials. Five powder-type alginate impression materials (Alginoplast EM, Aroma Fine, Algiace Z, Coe Alginate, Jeltrate Plus) and a paste-type alginate impression material (Tokuso AP-1) were used. The dynamic viscosity immediately after mixing was measured by means of a controlled-stress rheometer. The gelation times were determined according to Japanese Industrial Standards (JIS) T6505, and recovery from deformation, strain in compression and compressive strength were determined according to the International Organization for Standardization (ISO) specification 1563. Detail reproduction and surface roughness of type III dental stones (New Plastone, New Sunstone) and a type IV dental stone (Die Stone) were evaluated using a ruled test block as specified in the ISO specification 1563 and a profilometer, respectively. The alginate impression materials evaluated in this study were all in compliance with the ISO specification 1563 and JIS T6505. The alginate impression materials had similar mechanical properties after gelation, whilst a wide range of dynamic viscosity immediately after being mixed, gelation times and compatibility with dental stones were found among the materials. The paste-type material had a higher dynamic viscosity and a shorter gelation time than the powder-type materials. The best surface quality was obtained with the paste-type material/type III dental stone cast combinations. The materials should be selected in consideration of initial flow, setting characteristics and compatibility with dental stones. The results suggested that a paste-type material would better meet the requirements of an alginate impression material.

Alginates↗

Fungicidal effect of three new synthetic cationic peptides against Candida albicans.

OBJECTIVE: Peptide antibiotics are considered a new class of antifungal agents. Of these, an alpha-helical, cationic peptide termed Dhvar 4, a relative of salivary histatin has been shown to be an antifungal of relatively high potency. Similarly, lactoferricin B (LFB) and a derivative thereof, LFB(17-30), disrupts the fungal cell membrane and acts against Candida albicans. As Dhvar 4 and LFB(17-30), exhibit almost identical amino acid sequences at their C-terminal, we hypothesized that laboratory synthesis of peptides with an alpha-helical structure and having similar amphipathic properties could lead to products with candidacidal activity. Hence, three such peptides - JH8194, JH8195 and JH 8944, were synthesized and their antifungal properties compared with recognized antifungals LFB, LFB(17-30), human lactoferricin (LFH), Histatin-5 and Dhvar 4, against two isolates of C. albicans. MATERIALS AND METHODS: The antifungal agents were synthesized and their secondary structures evaluated according to a previously described protocol of Situ and Bobek (2000)Antimicrob Agents Chemother44: 1485-1493. The C. albicans strains were oral isolates from a human immunodeficiency virus-infected (isolate A2) and a healthy (A6) individual. A standard concentration of yeasts was exposed to a range of dilutions of the agents for a specific duration and the cell death (viability) in terms of the resultant colony forming units ml(-1) was quantified. RESULTS: Dhvar 4, showed the most alpha-helical propensity, and was the least fungicidal while LFB and LFB(17-30) showed the highest antifungal potential, and demonstrated total kill of A6, and A2 at 5 and 10 microM concentrations, respectively whilst LFH killed both isolates at a l0 microM concentration. Of the three new synthetic peptides, JH 8194 was the most potent (total kill of A6/A2 strains at 1.25/2.5 microM), followed by JH 8195 (total kill of A6/A2 strains at 5/10 microM while JH 8944 was the least potent as a 25 microM concentration was required to kill either strain of Candida. On further analyses of the relationship between pI value of the peptides and their anticandicidal activity, a significant positive correlation was noted. In order to rule out a cytotoxic effect of the new synthetic peptides we compared the fungicidal and hemolytic activities under similar incubation conditions using freshly isolated erythrocytes and all three peptides exhibited no detectable hemolysis upto an concentration of 100 microM in contrast to the polyene antifungal amphotericin B that elicited significant initiation of hemolysis at a concentration of 5.0 microM. CONCLUSION: Our data suggest that laboratory synthesis of agents with an alpha-helical structure and having amphipathic properties similar to known, natural antifungal agents may be a promising avenue to generate products with improved antifungal activity.

Amino Acid Sequence↗

Non-surgical approach to advanced chronic periodontitis: a 17.5-year case report.

This 17.5-year longitudinal case report details the treatment of advanced chronic periodontitis in a female patient commencing at 34 years of age. The woman was provided with periodontal care comprising of temporary fixation, scaling and root planing, intra-pocket irrigation using a root canal syringe and regular supervised maintenance. The patient presented with a 10-year history of bleeding gums. Therapy conducted in general practice had included simple curettage and irrigation. However, these treatments proved unsuccessful and the patient often changed dentists seeking better treatment. She presented to the University Dental Hospital, for diagnosis and treatment of her periodontal conditions after her mandibular lateral incisor had exfoliated. On presentation a purulent exudate could be expressed from all of the pockets. All anterior teeth, excluding the maxillary canines, demonstrated +2 to +3 mobility. The patient did not want any surgical treatment or her teeth extracted. It was decided to treat the patient conservatively without surgery. By postponing extraction, the authors were in a better position to determine the prognosis of the remaining teeth after the infection was under control. Although six teeth were extracted during the 17.5 years, this case report suggests that a non-surgical approach is a viable option while maintaining regular visits for periodontal care.

Adult↗

Mucin expression in pleomorphic adenoma of salivary gland: a potential role for MUC1 as a marker to predict recurrence.

BACKGROUND: Pleomorphic adenoma of the salivary gland (PA) is essentially a benign neoplasm. However, patients with recurrent PA are difficult to manage. There are rare reports on useful immunohistochemical markers to detect a high risk of recurrence when the primary lesions are resected. AIMS: To find a new marker to predict the recurrence of PA. METHODS: Primary lesions of PA were collected from nine patients showing subsequent recurrence and from 40 patients without recurrence during at least 10 years of follow up of the disease. Paraffin wax embedded tumour samples of the two groups were examined for the expression profiles of MUC1 (differentially glycosylated forms), MUC2, MUC4, MUC5AC, and MUC6 using immunohistochemistry. Several clinicopathological factors were also examined. RESULTS: In univariate analysis of the factors examined, MUC1/DF3 high expression (more than 30% of the neoplastic cells stained) in the primary lesions was seen more frequently in patients with recurrence (four of nine) than in those without recurrence (three of 40; p = 0.011). Larger tumour size (more than 3.0 cm) of the primary PA was also a significant (p = 0.035) risk factor for the recurrence of PA. In multivariate analysis, only high expression of MUC1/DF3 was found to be a significant independent risk factor for the recurrence of PA (p = 0.021). CONCLUSIONS: Expression of MUC1/DF3 in PA is a useful marker to predict its recurrence. Those patients with PA showing positive MUC1/DF3 expression should be followed up carefully.

Adenoma, Pleomorphic↗

Morules in endometrial carcinoma and benign endometrial lesions differ from squamous differentiation tissue and are not infected with human papillomavirus.

BACKGROUND: Squamous differentiation/squamous metaplasia is often associated with endometrial adenocarcinoma and benign lesions, such as endometrial hyperplasia and chronic endometritis. Morules have distinct histological characteristics, and are referred to as squamous metaplasia or squamoid metaplasia. AIM: To focus on the histological characteristics of morules and clarify the difference between morules and squamous differentiation. MATERIALS/METHODS: Twenty endometrioid carcinomas with morules or squamous differentiation, five adenosquamous carcinomas, and eight non-carcinomatous endometrial lesions with morules were investigated. Numerous antibodies for epithelial membrane antigen (EMA), involucrin, cytokeratins, neuropeptides, and oncofetal antigens were used for immunohistochemistry. In situ hybridisation and polymerase chain reaction were used to detect human papillomavirus (HPV). RESULTS: The morules observed were uniform cell clusters, with no squamous differentiation. They were immunonegative for epithelial antigens including involucrin, EMA, and cytokeratins, but were positive for neurone specific enolase. A few morules were immunopositive for acetylcholine esterase, and one case was positive for somatostatin; neither oncofetal nor proliferative cell markers, including blood group A, B, and AB, or other neuropeptides were demonstrated in the morules. HPV DNA was not found in either the morules in the carcinomas or in the benign lesions. However, true squamous differentiation tissue in four endometrioid carcinomas and two adenosquamous carcinomas was HPV positive using in situ hybridisation. CONCLUSION: Morules are histologically distinct from squamous metaplasia/squamous differentiation tissue. Morules are thought to be neuroectodermal-like cell clusters, and are not infected with HPV. In contrast, some of the true squamous differentiation tissue was associated with HPV infection.

Adenocarcinoma↗

Individual trait anxiety levels characterizing the properties of zen meditation.

Meditation is a specific consciousness state in which deep relaxation and increased internalized attention coexist. There have been various neurophysiological studies on meditation. However, the personal predispositions/traits that characterize the properties of meditation have not been adequately studied. We analyzed changes in neurophysiological parameters [EEG coherence and autonomic nervous activity using heart rate variability (HRV) as an index] during Zen meditation, and evaluated the results in association with trait anxiety (assessed by Spielberger's State-Trait Anxiety Inventory) in 22 healthy adults who had not previously practiced any form of meditation. During meditation, in terms of mean values in all subjects, an increase in slow alpha interhemispheric EEG coherence in the frontal region, an increase in high-frequency (HF) power (as a parasympathetic index of HRV), and a decrease in the ratio of low-frequency to HF power (as a sympathetic index of HRV) were observed. Further evaluation of these changes in individuals showed a negative correlation between the percent change (with the control condition as the baseline) in slow alpha interhemispheric coherence reflecting internalized attention and the percent change in HF reflecting relaxation. The trait anxiety score was negatively correlated with the percent change in slow alpha interhemispheric coherence in the frontal region and was positively correlated with the percent change in HF. These results suggest that lower trait anxiety more readily induces meditation with a predominance of internalized attention, while higher trait anxiety more readily induces meditation with a predominance of relaxation.

Adult↗

Quantitative analysis of the effects of hyaluronan and aggrecan concentration and hyaluronan size on the elasticity of hyaluronan-aggrecan solutions.

We determined elasticity (G') and viscosity (G'') of various aggrecan-hyaluronan solutions using a controlled-stress rheometer with high (10 Hz) to low (0.1 Hz) frequencies. Aggrecan solution (50 mg/ml) alone showed little elasticity at any frequency, but the addition of 3300 kDa hyaluronan at 0.001-0.1 mg/ml markedly increased the elasticity, but not the viscosity, at all frequencies. Increasing hyaluronan concentration at >0.1 mg/ml did not further increase the elasticity of the aggrecan solution, and the elasticity of the aggrecan-hyaluronan complex solution reached a plateau at a 500:1 (w/w) ratio. In studies with increasing concentrations of aggrecan and a constant concentration (0.5 mg/ml) of 3300 kDa hyaluronan, aggrecan induced elasticity only at >20 mg/ml, indicating the presence of a critical concentration for elasticity. In the presence of 50 mg/ml aggrecan, 1000 kDa hyaluronan had far less effect on the elasticity of the aggrecan solution than did 3300 kDa hyaluronan. These findings suggest that only approximately 50% reduction in aggrecan concentration (<20 mg/ml), or reduced hyaluronan size (<1000 kDa)--compared with their physiological levels in young cartilage--can abolish the elastic network of the aggrecan-hyaluronan complex.

Aggrecans↗

HLA-related subpopulations of MS in Japanese with and without oligoclonal IgG bands. Human leukocyte antigen.

BACKGROUND: Oligoclonal IgG bands (OCB) are present in most patients with MS in Western countries; however, in Japanese MS patients, the OCB-positive rate is not as high. A relationship between immunogenetic backgrounds, namely, human leukocyte antigen (HLA) DR2 and DR4 positivity, and OCB production in MS patients from Hokkaido, the northernmost island of Japan, has been previously suggested by the authors. OBJECTIVES: To investigate the role of OCB in Japanese MS and to verify the interaction between immunogenetic backgrounds and OCB positivity. METHODS: OCB, DR2(15), and DR4 positivity were studied in 45 patients with newly diagnosed MS. In addition to confirming the authors' previous findings, the clinical and demographic features, MRI findings, OCB positivity, and DRB1*15 and DRB1*04 polymorphisms of an expanded data set of 99 MS patients were investigated by using multivariate analysis. Patients with opticospinal MS (OS-MS) were excluded from this study. RESULTS: A relatively low OCB-positive rate (53.3%), HLA-DR15 association with OCB-positive MS (p = 0.0044), and DR4 association with OCB-negative MS (p = 0.0410) were confirmed. DR15 was not associated with OCB-negative MS. Demographic features, disease course, and disability were similar in the OCB-negative and OCB-positive group, whereas there was a preponderance of women in the OCB-positive group. An independent negative association of DRB1*0405 (p = 0.0021, adjusted odds ratio = 0.21) with OCB positivity was found. CONCLUSIONS: MS is heterogeneous in its association with HLA alleles, and based on the immunogenetic differences, the MS patients in this population include at least two HLA-related subpopulations with and without OCB.

Adolescent↗

Constant light housing attenuates circadian rhythms of mPer2 mRNA and mPER2 protein expression in the suprachiasmatic nucleus of mice.

Constant light (LL) or constant dark (DD) environmental lighting conditions cause a free-running period and activity reduction in the rodent behavioral circadian rhythm. In order to understand the molecular process underlying behavioral rhythms in LL or DD housing conditions, we examined the circadian profile of mPer2 mRNA and mPER2 in the suprachiasmatic nucleus (SCN), a main oscillator, of free-running mice. The circadian expression rhythm of mPer2 in the SCN was dampened under 7-day LL conditions, whereas that of mPER2 protein was moderately attenuated and its expression peak delayed. The circadian expression of mPer2 and its product was slightly attenuated and advanced by 7-day DD conditions. With arrhythmic behavioral activity caused by long-term LL housing, mPER2 protein lost its rhythmicity in the SCN. On the other hand, LL or DD housing did not affect the mPer2 gene and its product in the cerebral cortex. The present results suggest that mPER2 circadian expression in the SCN corresponds well with behavioral circadian oscillation under LL or DD conditions. Thus, the behavioral circadian rhythm seems to correlate with molecular clock works in the SCN.

Analysis of Variance↗

Real-time interaction of oral streptococci with human salivary components.

Oral streptococci are present in large numbers in dental plaque and several types interact with the enamel salivary pellicle to form a biofilm on tooth surfaces. The respective affinity of individual streptococci for salivary components has an influence on the etiologic properties of oral biofilm in the development of dental caries. We studied real-time biospecific interactions between oral streptococci and salivary components utilizing biosensor technology to analyze surface plasmon resonance. Streptococcus sanguis and Streptococcus mutans showed significant responses for binding to salivary components, in comparison with other bacteria. Further, the association rates (4.1 x 10-11/bacterium) and dissociation rate (5.7 +/- 0.9 x 10-3 Second(s)-1) were higher for S. sanguis than for S. mutans (2.4 x 10-11 and 2.9 +/- 0.8 x 10-3) and Streptococcus mitis (1.3 x 10-11 and 3.5 +/- 1.3 x 10-3). However, the association equilibrium constants (8.2 S/bacterium) for S. mutans was 2 times higher in than S. mitis (3.8) and slightly higher than S. sanguis (7.2). These findings may provide useful information regarding the mechanism of early biofilm formation by streptococci on the tooth surface.

Adult↗

Caveolin-3 gene mutation in Japanese with rippling muscle disease.

OBJECTIVES: Rippling muscle disease (RMD) is a rare myopathy characterized by percussion-induced rapid muscle contractions, muscle mounding, and rippling. Recently a caveolin-3 gene (CAV3) mutation was identified in patients with autosomal dominant RMD. The objective of this study was to determine whether a similar mutation was present in two Japanese families with this condition. PATIENTS AND METHODS: Clinical examination, mutational analysis, and muscle immunohistochemistry were carried out in six patients from two Japanese RMD pedigrees. RESULTS: Apart from the atrophy of the intrinsic muscles in their hands and a slight muscle weakness in their fingers, the clinical features of our patients were compatible with RMD. Our investigation revealed a CAV3 missense mutation, i.e. Arg26Gln in both families. Immunohistochemistry performed on a muscle biopsy specimen showed reduced caveolin-3 surface expression. CONCLUSIONS: Japanese RMD also appears to result from a CAV3 mutation.

Adult↗

In vitro cariogenic potential of Candida albicans.

The adherence and dissociation of Candida albicans, C. tropicalis, Streptococcus mutans and S. sanguis to six substrates including hydroxylapatite (HAP) which exhibit various hydrophobicity, was examined by the use of a bioluminescent adenosine triphosphate (ATP) assay. Dissolution of HAP by C. albicans or S. mutans was determined spectrophotometrically by the use of o-cresolphthalein complexone. In the adherence of C. tropicalis, S. mutans and S. sanguis, the amount of adherent cells correlated with the hydrophobicity of the substrates. In contrast, the adherence of C. albicans to HAP was extraordinary high, although the adherence of the fungi also correlated with the hydrophobicity of the substrates, except for HAP. The yeasts attached to HAP was effectively removed by high concentration of either phosphate or calcium ions. The amount of calcium-release from HAP caused by C. albicans and S. mutans was 113 microg ml(-1) (final pH = 3.45), and 5.4 microg ml(-1) (final pH 4.81), respectively and the maximum growth of C. albicans and S. mutans was 10(7) cfu ml(-1) and 7.4 x 10(12) cfu ml(-1), respectively. The results, taken together, suggest that C. albicans adhere to HAP specifically through electrostatic interaction, and that, in a much smaller number (1.0/7.4 x 10(5)), C. albicans possesses the ability to dissolve HAP to a greater extent (approximately 20-fold) when compared with S. mutans.

Bacterial Adhesion↗