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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 361 records · Page 20Linked to original sources
PubMed1994

Influence of thickness and location on the residual monomer content of denture base cured by three processing methods.

The influence of thickness and location on the residual monomer content of acrylic resin plates was examined when they were processed by three methods: a conventional method, fluid resin technique, and a microwave curing method. The residual monomer contents were measured by gas liquid chromatography. The levels of residual monomer were influenced by the processing methods and thicknesses of acrylic resin specimens, but not by location within the specimens. These results suggest that dimensional accuracy and stability of acrylic resin dentures could be influenced by the processing method, the thickness of the bases, and the shape and size of the dentures.

Acrylic Resins↗
PubMed1994

Effects of denture cleansers on direct soft denture lining materials.

The deterioration of six commercial resilient denture lining materials immersed in seven groups of denture cleansers was investigated. Although the grades of deterioration of these soft liners were not related to the amount of peroxide content or the pH of denture cleansers, the effects of peroxide cleansers were, with few exceptions, more severe than those of the other types. For example, an enzyme cleanser caused severe changes of one soft liner. The grades of surface porosity were correlated well with the log of the gelation time of the tissue conditioners (except for one soft liner), in four kinds of peroxide cleansers. These results suggest that various components of denture cleansers and soft lining materials, particularly peroxides, in cleansers and gel formation components of soft liners play important roles in the deterioration of soft liners caused by cleansers.

Acrylic Resins↗
PubMed1994

Involvement of vasoactive intestinal polypeptide in NMDA-induced phase delay of firing activity rhythm in the suprachiasmatic nucleus in vitro.

Glutamate has been reported to be involved in the transmission of photic information from the retina to the suprachiasmatic nucleus (SCN). Therefore, we investigated whether the application of N-methyl-D-aspartate (NMDA), a glutamate receptor agonist could, reset the circadian rhythm of SCN firing activity in vitro. Treatment with NMDA for 1 h between projected zeitgeber time (ZT) 13-14 produced a phase delay in a concentration-dependent manner. The NMDA-induced phase delay was antagonized by an NMDA-receptor antagonist, MK-801 (100 microM). The retinohypothalamic tract has been reported to make terminals on neurons possessing vasoactive intestinal polypeptide (VIP). Therefore, we investigated the effect of NMDA on VIP release from the SCN and on VIP immunoreactivity in the SCN. Application of NMDA for 15 min between ZT 13-15 increased release of VIP from the SCN. In contrast to release, the content of VIP in the SCN tissue was reduced by application of NMDA. Immunohistochemical analysis revealed that application of NMDA for 4 h or 1 h reduced VIP immunoreactivity in the SCN. To investigate the possibility that VIP released by NMDA could reset SCN neuronal activity, we examined the effects of VIP on the SCN neuronal activity rhythm. Co-treatment with VIP (1 microM) and gastrin-releasing peptide (1 microM) for 1 h between ZT 13-14 caused a phase-delay of SCN activity rhythm. These findings suggest that activation of NMDA receptors during early subjective night causes a phase delay of the SCN neuronal activity via facilitation of VIP release in this nucleus.

Animals↗
PubMed1994

Primary anaplastic large-cell lymphoma of the skin. A case report suggesting that regressing atypical histiocytosis and lymphomatoid papulosis are subsets.

A patient with primary anaplastic large-cell lymphoma of the skin with characteristic clinical findings is described. The diagnosis was made on the basis of histologic and immunohistochemical findings. The phenotype of the tumor cells was not determined, but rearrangement of the T-cell receptor beta gene indicated that the tumor was of T-cell lineage. Despite high-grade malignancy of the tumor cells, the patient unexpectedly had a benign clinical course. The findings in this case suggest that regressing atypical histiocytosis and lymphomatoid papulosis type A are subsets of anaplastic large-cell lymphoma.

Abdominal Neoplasms↗
PubMed1994

Cutaneous metastases of pancreatic carcinoma with unusual clinical features.

Cutaneous metastases from pancreatic carcinoma are uncommon. Eight cases have been described in the literature. The metastases display some common features such as umbilical nodules and the histologic pattern of adenocarcinoma. Our patient had erythematous infiltrated plaques in the left axilla and on the upper portion of the chest. A skin biopsy specimen disclosed many poorly differentiated atypical cells throughout the dermis. The diagnosis was confirmed by positive immunohistochemical staining for carbohydrate antigen 19-9.

Adenocarcinoma↗
PubMed1994

Hair fibrous protein compositions in some hereditary hair abnormalities determined by two-dimensional polyacrylamide gel electrophoresis.

S-carboxymethylated (SCM) fibrous proteins (FPs) from the scalp hairs of the three different hereditary hair abnormalities (trichorrhexis invaginata in Netherton's syndrome, pili trianguli et canaliculi in uncombable hair syndrome, and fine hair in anhidrotic ectodermal dysplasia) were analyzed by two-dimensional polyacrylamide gel electrophoresis. Comparison of the SCM FP compositions of the three hair abnormalities with that of the normal revealed that the SCM FP compositions of these three abnormal hairs were all electrophoretically different from each other and that of the normal.

Child↗
PubMed1994

Immunohistochemical localization of lysyl oxidase in normal human skin.

Lysyl oxidase (EC 1.4.3.13), a copper-dependent enzyme which catalyses the formation of aldehyde cross-links, and acts primarily on collagen and elastin, is known to be increased during wound healing and in fibrotic disorders including liver cirrhosis and atherosclerosis, and to be decreased in some hereditary connective tissue diseases and in malignant cell lines. A recent study showed that lysyl oxidase might possess tumour suppressor activity as an antioncogene for ras. Little is known about the localization of this enzyme in human skin. In this study, we determined immunohistochemically the localization of lysyl oxidase in normal skin of young and elderly subjects obtained from sun-exposed and unexposed regions of the body. All skin samples tested had similar distributions of lysyl oxidase. The enzyme was present both extracellularly and intracellularly. Extracellularly, a few granular aggregates of immunoreactants were observed along collagen and elastic fibres. These granules were more common in the adventitial portion of the dermis than in the reticular portion. Of all sun-exposed and unexposed regions studied, the skin of the face displayed the greatest amount of extracellular immunoreactants. Immunopositive granules were observed intracellularly in fibroblasts, vascular endothelial cells, sweat glands, sebaceous glands, arrector pili muscles and some keratinocytes. These findings provide evidence that, as suggested in recent reports, lysyl oxidase may have a variety of intracellular functions.

Adolescent↗
PubMed1994

Solitary glomus tumour with mucinous degeneration.

Four cases of solitary glomus tumour are reported, three of the angiomatous type, and one of the epitheliomatous type. In all cases, mucinous degeneration was seen, the extent of which correlated with the number of glomus cells.

Adult↗
PubMed1994

Treatment of linear localized scleroderma with the anti-allergic drug, tranilast.

A 14-year-old boy with linear localized scleroderma had a dramatic improvement in contractures after treatment with N-(3',4'-dimethoxycinnamoyl) anthranilic acid (tranilast, Rizaben). The observation that this anti-allergic drug was effective in localized scleroderma lends further support to the concept that mast cells play a role in increased collagen synthesis in this disease.

Adolescent↗
PubMed1994

Viscoelastic properties of tissue conditioners--influence of ethyl alcohol content and type of plasticizer.

The effect of both the ethyl alcohol content of liquids and the type of plasticizer on the viscoelastic properties after gelation of tissue conditioners was studied by means of a stress relaxation test. The results are summarized as follows. The liquids containing the larger percentages of ethyl alcohol produced the larger flow after gelation. Furthermore, the ethyl alcohol content had a significant influence on changes in viscoelastic properties with the passage of time. Flow properties were found to reduce rapidly with time of storage with an increase in the ethyl alcohol content. The use of benzyl benzoate produced the larger flow after gelation than dibutyl phthalate, which in turn produced the larger flow than butyl phthalyl butyl glycolate. The type of plasticizer, however, was found to have no influence on changes in viscoelastic properties with the passage of time.

Dental Materials↗
PubMed1994

Objective evaluation for bite plate therapy in patients with myofascial pain dysfunction syndrome.

An electromyographic study of the masseter and anterior temporal muscles together with questioning patients regarding subjective symptoms was performed on 15 patients with myofascial pain dysfunction (MPD) syndrome prior to and during bite plate therapy. The electromyographic study was evaluated by the slopes of the voltage tension (V/T) curves (calculated as the value of the relative inclination between the integrated electromyram and the biting force). The improvement of subjective symptoms was recognized earlier than the relief of objective symptoms by bite plate therapy. The results confirm that judgement of level of improvement following treatment of MPD syndrome is more appropriate through objective evaluation. Follow-up recording of the voltage tension can be considered to be an objective indicator for patients with MPD syndrome.

Adolescent↗
PubMed1994

Growth and/or acid production of Candida albicans on soft lining materials in vitro.

Effects of soft lining materials on the growth and/or acid production of Candida albicans were investigated using a simplified method monitoring the pH change in the growth medium. Reverse sigmoidal pH curves were observed with all samples and, as compared with acrylic, all soft lining materials inhibited fungal growth or acid production in the following way, i.e. delay of the beginning of a rapid and linear decline in pH, decreases in the rate of linear change in pH and increases in minimum pH. Further examinations using a surface-modified glass tube revealed that the order of Candida growth agreed with the relative hydrophobicity and adherence capacity of substrates, suggesting that this adherence capacity affected the yeast growth on their surfaces. Besides adherence capacities of substrates, the powder, liquid and plasticizer of some soft lining materials directly inhibited Candida growth. Thus, the results obtained here revealed that several factors within soft lining materials affected Candida growth and/or acid production.

Acrylic Resins↗
PubMed1994

Rhinophyma in Japan.

BACKGROUND: Rhinophyma is an end stage of acne rosacea. It results in a large nose due to a proliferation of sebaceous glands and fibrous tissue. Many cases of rhinophyma have been reported in the Western world; however, in Japan, rhinophyma has been an uncommon disease. METHODS: We present two patients associated with rhinophyma who were treated by cross-shaped full-thickness excision followed by direct closure and compare the rhinophyma in Japan with that in the West. RESULTS: To date, only 20 rhinophyma cases including our 2 cases have been reported in Japan. Epidemiologic factors of rhinophyma between the West and Japan do not differ except for location, malignancy and surgical treatment. CONCLUSIONS: In Japan, almost all cases are located on the lower half of the nose, treated by full-thickness excision followed by application of either skin grafts or direct closure. None have been malignant.

Aged↗
PubMed1994

Selective decrease of eumelanin in hypopigmented epidermis of hypomelanosis of Ito.

A Japanese infant had bilateral hypopigmented macules in a whorled or marble-cakelike configuration on her trunk and extremities. Her irides were bluish gray and her hair was dark brown. She had photophobia and macrocephaly with developmental delay. Analysis of peripheral lymphocytes and dermal fibroblasts disclosed a normal chromosomal pattern. A new finding was that the eumelanin content of the hypopigmented epidermis was decreased. We suggest that at least a portion of patients with this disorder have a defect in eumelanogenesis in hypopigmented skin.

Epidermis↗
PubMed1994

[The improvement on the nursing procedure for pregnant women and newborns and the decrease of Staphylococcus aureus infections in newborns and infants in our hospital].

Knowing the importance of prevention of Staphylococcus aureus infections, especially that of Methicillin-resistant S. aureus (herein after abbreviated as MRSA) in the newborn room, we improved the nursing procedure in the room and examined subsequent changes in the onset condition of the above infection in newborns and infants less than 1-year-old. The infection was detected in 13 cases of stage 1 (stage according to the nursing procedure since the opening of our hospital): 6 cases (all MRSA) had their onset in the room. MRSA was detected in 11 cases, suspecting a hospital cross infection in relation to the period of birth and coagulase type. The infection was detected in 9 cases of stage 2 (stage of prevention of inter-newborn hospital cross infection through environmental purification within the newborn room, through hand and finger disinfection of medical workers, through improved bathing, etc.); 2 cases (1 of MRSA, 1 of Methicillin-sensitive S. aureus [hereinafter abbreviated as MSSA]) had an onset in the room. MRSA was detected in 5 cases, but hospital cross infection was thought difficult to be responsible. The MRSA infection was detected in 4 pregnant cases (0.8%) of stage 3 (stage of effortful prevention of MRSA from carrying into the ward following examination of possible intra-nasal MRSA establishment in pregnant women in addition to similar newborn nursing to stage 2), indicating pregnant women's possible carrying MRSA into the newborn room. S. aureus infection was detected in 9 cases; 2 cases (MSSA) had an onset in the above room.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗