Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 397 records · Page 22Linked to original sources

PubMed1993

Facilitation of 2-deoxyglucose uptake in rat cortex and hippocampus slices by somatostatin is independent of cholinergic activity.

2-Deoxyglucose (2-DG) uptake is an index of regional glucose utilization which reflects predominantly activity in the axonal terminal of neuronal pathways. The present experiments showed that somatostatin elevated 2-DG uptake in rat cortex and hippocampus slices. Treatment with somatostatin-14 and somatostatin-28 markedly enhanced 2-DG uptake, whereas the amino-terminal fragment of somatostatin-28 did so only slightly. This effect appeared to be mediated by an interaction with somatostatin receptors because cyclo-somatostatin, a somatostatin antagonist, abolished the effect of somatostatin-14. The increase in 2-DG uptake caused by somatostatin-14 was blocked by the calcium channel antagonist, nifedipine, but not by tetrodotoxin, suggesting that the action of somatostatin does not require the initiation of impulse activity, somatostatin enhanced the KCl-induced release of acetylcholine, suggesting that a cholinergic mechanism is involved in the somatostatin-induced cellular responses. We therefore examined whether acetylcholine receptor antagonists block the somatostatin-induced increase in 2-DG uptake. Neither muscarinic nor nicotinic receptor antagonists affected the somatostatin-14-induced response. The present results suggest that somatostatin has a stimulatory effect on energy metabolism and that this effect is independent of acetylcholine receptor mechanism.

Animals↗

PubMed1993

Motor neuron disease and past poliomyelitis. Geographic study in Hokkaido, the northern-most island of Japan. ALS Study Group.

We carried out a survey on the cases of motor neuron disease (MND) occurring in Hokkaido between 1980 and 1989 in order to establish whether there is a relationship between MND and poliomyelitis. Hokkaido, the northern-most island of Japan, was one of the most affected areas during the poliomyelitis epidemic of the late 1940s to 1950s. We ascertained 389 cases of MND for these 10 years and 2,171 cases of paralytic poliomyelitis for the period 1949-1958, and analysed their geographic distributions. No significant correlation was found between MND and poliomyelitis in their geographic distributions.

Adult↗

PubMed1993

Difference in blood flow volume of the common carotid artery between vascular and non-vascular dementia detected by colour duplex sonography.

Using colour duplex sonography, blood flow volume in the common carotid artery was measured in 72 demented patients and 28 normal controls. Thirty-five patients with a Hachinski's ischaemic score of 7 or above and marked ischaemic lesions on CT were assigned to the vascular dementia (VD) group. Thirty-three patients with probable Alzheimer's disease according to the NINCDS-ADRDA criteria, 2 patients with Parkinson's disease, 1 patient with spinocerebellar degeneration, and 1 patient with Pick's disease were assigned to the non-vascular dementia (nonVD) group. The sum of blood flow volume in the bilateral common carotid arteries (CCA flow) in the nonVD group and in the VD group was lower than that in the control group. The CCA flow in the VD group was lower than that in the nonVD group. Comparison of patients matched for both age and the Hasegawa's dementia rating scale also revealed lower CCA flow in the VD group than in the nonVD group. Linear discriminant function analysis showed that nearly 90% of the demented patients were correctly diagnosed as having VD or as having nonVD. These results show the usefulness of colour duplex sonography in the differential diagnosis of patients with dementia.

Aged↗

PubMed1993

Interactions between denture lining material, protein pellicles and Candida albicans.

The interactions between pellicles derived from saliva, serum, mucin and lysozyme deposited on lining material (tissue conditioner) and Candida albicans were investigated by monitoring pH changes associated with protein-free and protein-coated lining material and by ultrastructural observations of yeast colonization. No significant differences in pH reduction between culture media in contact with the protein-free, control lining materials and those coated with saliva, serum or mucin were observed after 120 h of incubation. However, scanning electron microscopy revealed that much greater numbers of the yeasts colonized the saliva- or serum-coated lining material than the lysozyme-, mucin-coated or control material. Hyphal invasion was observed in saliva-coated lining material. These results suggested that denture pellicle derived from saliva and/or serum may potentiate candidal colonization of denture lining materials.

Adhesiveness↗

PubMed1993

The fungicidal effect of human lactoferrin on Candida albicans and Candida krusei.

Five oral isolates each of Candida albicans and Candida krusei were studied for their sensitivity to the fungicidal effect of human lactoferrin. Significant inter- and intraspecies variations were observed and with most isolates the sensitivity of C. krusei to lactoferrin was greater than that of C. albicans. Fungicidal activity of lactoferrin was dose-dependent and observable only with the iron-free form of the molecule (apo-lactoferrin). Iron-saturated lactoferrin was ineffective against all isolates. Supernatant protein assays and scanning electron microscopy indicated cell surface alterations--leakage of proteins and formation of surface blebs--only in those Candida isolates that were sensitive to apo-lactoferrin. As lactoferrin is a common, non-immune, mucosal defence protein, its varying mode of action against C. albicans and C. krusei may be related to their different oral carriage rates.

Analysis of Variance↗

PubMed1993

Mercury and selenium contents in amyotrophic lateral sclerosis in Hokkaido, the northernmost island of Japan.

We evaluated the pathogenicity of mercury (Hg) and selenium (Se) which are supposed to be one of the risk factors in the development of amyotrophic lateral sclerosis (ALS). Hg and Se contents were measured in plasma, blood cells, scalp hair samples of 21 sporadic ALS patients and 36 controls, who included 19 patients with other neurological diseases, in Hokkaido, the northernmost island of Japan. Hg and Se levels in plasma and blood cells of ALS patients were significantly lower in advanced staged ALS patients than controls. Low Hg and Se contents in ALS, being correlated with their disabilities and nutritional conditions, would rather reflect the disease contracted states than the pathogenic roles in ALS.

Adult↗

PubMed1993

T-cell receptor gene rearrangement in cells infiltrating skin eruptions specific to adult T-cell leukemia.

We examined T-cell receptor gene rearrangement in skin lesions and peripheral blood from 6 patients with adult T-cell leukemia (ATL) using the Southern blot method and a c beta 1 probe. A rearrangement signal common to skin lesions of all 6 patients was observed. One patient (Case 4) exhibited another rearrangement signal in the skin lesion and an identical signal was detected in the peripheral blood. This is the first report describing a specific pattern of T-cell receptor gene rearrangement in ATL. The signal obtained is assumed to represent receptors of T cells involved in surveillance of HTLV-I infected T cells.

Aged↗

PubMed1993

Nucleolar organizer regions are independently associated with a shortened survival in patients with non-small cell lung cancer.

We examined nucleolar organizer regions (Ag-NOR) in 102 patients with non-small cell lung cancer (NSCLC). Ag-NOR counts were generally higher in tumours from more advanced stages, or in poorly differentiated adenocarcinomas. Six potential-prognostic indicators included sex, age, year of operation, histology, stage and Ag-NOR count. Stage and Ag-NOR counts had a significant prognostic value in the univariate analysis for 79 patients who died of their lung cancer. In the multivariate analysis, high Ag-NOR counts as well as disease stage were independently associated with a poor prognosis. Furthermore we divided patients into three groups according to their Ag-NOR counts and found that in patients with stage I and II disease higher Ag-NOR counts were associated with shortened survival. This trend did not continue in patients with stage III and IV disease.

Adenocarcinoma↗

PubMed1993

Angiosarcoma of the chest wall with a gastric metastasis.

A rare case of chest-wall angiosarcoma with high tendency of local recurrence and with a solitary gastric metastasis is reported. The patient was an 84-year-old man who had a left lateral thoracic mass with a colic pain. The histological diagnosis of a biopsied specimen suggested an angiosarcoma. The first resection was performed, the resected specimen consisted of the 8th, 9th and 10th ribs including the tumor. However the tumor recurred around the primary site and the second resection was undertaken eight months after the first resection. Only three months after the second resection a second chest-wall recurrence together with a solitary gastric metastasis was found. Progressive emaciation, anemia and thrombocytopenia became evident, and the patient died the 40th day after the gastrectomy. Primarily a wide resection of the chest wall beyond the pathologically negative region around the tumor is thought to be necessary.

Aged↗

PubMed1993

Roles of the splenic cytokines and arachidonic acid metabolites in severe hepatic injury after lipopolysaccharide injection in chronically alcohol-fed rats.

We examined the early changes after lipopolysaccharide (LPS) injection in chronically alcohol-fed rats with or without splenectomy. Administration of 2 mg/kg body weight LPS caused severe hepatic injury. The plasma aspartate aminotransferase (ASAT) activity was significantly higher in sham-operated rats 8 hr after LPS injection than in splenectomized rats. The plasma tumor necrosis factor (TNF) activity was also significantly higher 1 hr after LPS injection in sham-operated rats than in splenectomized rats. The plasma thromboxane (TX) B2/6-keto-prostaglandin (PG) F1 alpha ratio increased in sham-operated rats after LPS injection. Therefore, the balance of arachidonic acid metabolites was in a hypercoagulated state in sham-operated rats after the LPS injection. Neutrophil infiltration into liver tissue increased in sham-operated rats after the LPS injection. The cytokines and arachidonic acid metabolites released from the spleen after LPS injection in alcohol-fed rats may play important roles in severe hepatic injury.

Animals↗

PubMed1993

Clinical and pathological features, and the mechanism of development in severe alcoholic hepatitis, especially in comparison with acute type fulminant hepatitis.

Among the patients with alcoholic hepatitis, the patients with severe alcoholic hepatitis (SAH) were distinguished by clinical course, laboratory data and histological findings. The aim of this study was to clarify the clinicopathological features, pathological condition and pathogenesis of SAH. Twenty-four SAH patients were compared with 55 patients with acute type fulminant hepatitis (FH) and the other types of alcoholic liver disease. SAH showed a very poor prognosis with a survival rate of 25% and was complicated by multiple organ failure earlier than FH. IgA class lipid A antibody, endotoxin (Et) and tumor necrosis factor-alpha (TNF-alpha) levels in the blood well reflected the pathological condition and severity of SAH. The white blood cell count in the peripheral blood was thought to be the simplest indicator for the prediction of the prognosis of SAH. In conclusion, SAH involves hyper-endotoxemia due to dysfunction of the reticuloendothelial system in the liver, and cytokines including TNF-alpha and neutrophils play an important role in the severity of liver injury.

Adult↗

PubMed1993

Long-term complications of reconstruction of the heel using a digitorum brevis muscle flap.

Seven patients who had surgery for malignant skin tumors of the heel were followed up for several years. The reconstructive procedure performed was repair of the large skin defect after excision of a tumor, by using a flexor digitorum brevis muscle flap and an overlying free graft. Although this procedure is a good method without any serious complications, no long-term follow-up data supporting this opinion have been reported. In this study, plantar flexion of the toes and flattening of the plantar arch appeared 3 months after surgery and developed for 1 year, and the patients complained of easy fatigability in walking and difficulty in going up stairs. These sequelae were probably due to sacrifice of the flexor digitorum brevis muscle. We feel that this procedure should be replaced by another procedure that does not sacrifice any muscle, for example, that using a medial plantar flap.

Aged↗

PubMed1993

Acquired dermal melanocytosis of the hand: a new clinical type of dermal melanocytosis.

We report a 22-year-old man with acquired dermal melanocytosis on the hand which developed without any history of previous inflammation. He had no history of contact with or oral administration of any drugs or metals which might have caused pigmentation. Histopathologically, spindle-shaped dermal melanocytes were observed running parallel to the collagen bundles and scattered in all portions of the dermis. The dopa reaction of these cells was positive. Ultrastructurally, dermal melanocytes containing numerous melanosomes (stages II to IV) which were surrounded by the extracellular sheath were observed. Differential diagnosis of other dermal melanocytosis was discussed.

Adult↗

PubMed1993

Effects of ultraviolet-B and PUVA on ornithine decarboxylase activity, DNA synthesis, and protein kinase C activity in mouse skin.

Ultraviolet-B and PUVA share several biological events with phorbol ester tumor promoters. The effects of ultraviolet-B irradiation and topical PUVA treatment on ornithine decarboxylase activity, DNA synthesis, and protein kinase C activity, which are known to be induced or activated by phorbol ester tumor promoter, were investigated in hairless mouse skin. Ornithine decarboxylase activity was remarkably enhanced by ultraviolet-B and PUVA. Although PUVA did not affect DNA synthesis significantly, ultraviolet-B stimulated epidermal DNA synthesis approximately 5-fold over control values at 48 h. However, unexpectedly, neither cytosolic nor membrane-bound protein kinase C activity showed any change during the 2 h after either treatment. These results suggest that the protein kinase C system is not involved in the initial signal transduction system of ultraviolet-B or PUVA, unlike the case with phorbol ester tumor promoter.

Animals↗

PubMed1993

Chédiak-Higashi syndrome: report of a case and review of the Japanese literature.

We report the case of a Japanese female infant with Chédiak-Higashi syndrome born to consanguineous parents. At birth she had fair skin but, when she was three months old, marked hyperpigmentation of the sun-exposed skin areas developed. Microscopic examination of blood and electron microscopic examination confirmed the diagnosis. She enjoyed good health until she was two years old when she had pneumonia with marked hepatosplenomegaly. It is important for dermatologists and pediatricians to be aware of the skin manifestations of this disease because hyperpigmentation after sun exposure may be a characteristic, initial feature of this condition.

Chediak-Higashi Syndrome↗

PubMed1993

Detection of human T-cell lymphotropic virus type-1 proviral DNA in the saliva of an adult T-cell leukaemia/lymphoma patient using the polymerase chain reaction.

We report a case of adult T-cell leukaemia/lymphoma (ATLL), in whom the polymerase chain reaction (PCR) on genomic DNA from saliva demonstrated the monoclonal integration of human T-cell lymphotropic virus type-1 (HTLV-1) proviral DNA in lymphocytes in the saliva. These results provided evidence of the possibility of saliva-borne transmission of HTLV-1.

Base Sequence↗

PubMed1993

Effects of colchicine on the induction of ornithine decarboxylase and its gene expression by the phorbol ester tumour promoter.

The activity and gene expression of ornithine decarboxylase (ODC, an indicator of tumour promotion) were induced by the phorbol ester tumour promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), in mouse skin. In the present study, the effect of colchicine, a microtubule-disrupting agent, on ODC activity and its gene expression were investigated. On administration of colchicine (100 micrograms) intraperitoneally 1.5 h before TPA treatment, ODC activity and ODC mRNA levels stimulated by TPA were suppressed to about 52 and 64%, respectively. These results suggest the involvement of a microtubule or colchicine-sensitive substrate in the signal transduction system for gene expression.

Animals↗

PubMed1993

Initial flow of tissue conditioners--influence of composition and structure on gelation.

The effects of the molecular weight of polymer powders, the ethyl alcohol content of the liquids, the type of plasticizer and the polymer powder/liquid ratio on viscoelastic properties during gelation of tissue conditioners were studied with an oscillating rheometer. The results showed that: (i) The gelation time decreased exponentially with increases in molecular weight of the polymer powder and with powder/liquid ratio. There were linear relationships between the log of gelation time, and both the molecular weight of the polymer powder and the powder/liquid ratio. (ii) In general, gelation time decreased exponentially with increases in ethyl alcohol content. However, the relationship between the log of the gelation time and ethyl alcohol content fitted a second-order polynomial. (iii) The type of plasticizer affected gelation time. The order of gelation times was: benzyl benzoate < dibutyl phthalate < butyl phthalyl butyl glycolate. The initial flow of tissue conditioners could be controlled over a wide range by varying the molecular weight of the polymer powders, the ethyl alcohol content, the powder/liquid ratio and the type of plasticizer.

Acrylic Resins↗