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Biomedical subjects

M Esaki

Publications and source records attributed to M Esaki.

At least 37 records · Page 2Linked to original sources
PubMed1999

Local drug delivery system using ceramics: vacuum method for impregnating a chemotherapeutic agent into a porous hydroxyapatite block.

We performed an experimental study on a new drug delivery system that employs a porous hydroxyapatite block (HAb) (composition: Ca10(PO4)6(OH)2)) to conduct sustained release of a chemotherapeutic agent. To confirm penetration of the agent into the HAb (2 cm3), an aqueous solution containing eosin dye was used at various vacuum pressures. To estimate the storage capacity of the HAb, blocks were weighed before and after being impregnated with the aqueous dye solutions, and the capacity of the block was calculated from the increase in weight after vacuum. In this slow-release study using vacuum, the anti-cancer drug methotrexate (MTX) was used in vitro. Four HAb (1 cm3) containing different concentrations of MTX, ranging from 1.22 to 2.38 mg per block, were studied. All were found to release the drug, maintaining a mean concentration of 0.22 to 0.32 microg/ml even after twelve days. This concentration is high enough to be effective against tumor cells. The results suggest that HAb impregnated with a chemotherapeutic agent using a simple vacuum system may serve as a valuable new method of administering local chemotherapy, primarily when used as a strut graft for bone defects. This new drug delivery system can also be used as an adjuvant material in extended curettage, which can also discourage recurrence of benign tumors without any risk of systemic toxicity.

Journal Article↗
PubMed1999

Polymorphism of heat-shock protein gene HSP70-2 in Crohn disease: possible genetic marker for two forms of Crohn disease.

BACKGROUND: Previous reports have shown that heat-shock protein 70 (HSP70) may be associated with Crohn disease. However, genetic analysis of the HSP70 gene in Crohn disease has not been done. The aim of this study is to investigate whether HSP70-2 gene polymorphism is involved in susceptibility to Crohn disease in the Japanese population and whether it correlates with clinical manifestation of the disease. METHODS: A total of 108 genetically unrelated patients with Crohn disease and 108 healthy controls were typed for HSP70-2 PstI polymorphism by restriction fragment length polymorphism analysis (alleles A and B). Patients with Crohn disease were classified into two types: either perforating or non-perforating. RESULTS: Genotype and allele frequency did not differ between patients and controls. In patients with Crohn disease, allele A frequency was significantly higher in the non-perforating than in the perforating type (P = 0.02). When patients with Crohn disease of more than 6.7 years' duration were assessed, the differences in genotype and allele frequency between the two groups became more significant (P < 0.001 and P < 0.001, respectively). CONCLUSIONS: These data suggest that HSP70-2 gene polymorphic allele A is a possible genetic marker of less severe clinical phenotype in Japanese patients with Crohn disease.

Adolescent↗
PubMed1999

Activation process of dipteran-specific insecticidal protein produced by Bacillus thuringiensis subsp. israelensis.

Dipteran-specific insecticidal protein Cry4A is produced as a protoxin of 130 kDa in Bacillus thuringiensis subsp. israelensis. Here we performed the in vitro processing of Cry4A and showed that the 130-kDa protoxin of Cry4A was processed into the two protease-resistant fragments of 20 and 45 kDa through the intramolecular cleavage of a 60-kDa intermediate. The processing into these two fragments was also observed in vivo. To investigate functional properties of the two fragments, GST (glutathione S-transferase) fusion proteins of the 60-kDa intermediate and the 20- and 45-kDa fragments were constructed. Neither the GST-20-kDa fusion protein (GST-20) nor the GST-45-kDa fusion protein (GST-45) was actively toxic against mosquito larvae of Culex pipiens, whereas the GST-60-kDa intermediate fusion protein (GST-60) exhibited significant toxicity. However, when the two fusion proteins GST-20 and GST-45 coexisted, significant toxicity was observed. The coprecipitation experiment demonstrated that the two fragments associated with each other. Therefore, it is strongly suggested that the two fragments formed an active complex of apparently 60 kDa. A mutant of the 60-kDa protein which was apparently resistant to the intramolecular cleavage with the midgut extract of C. pipiens larvae had toxicity slightly lower than that of GST-60.

Amino Acid Sequence↗
PubMed1999

[An autopsy case of elderly idiopathic enlargement of the right atrium].

We report an autopsy case of an 88-year-old man with idiopathic enlargement of the right atrium which is considered to be the oldest case reported. The patient was given a diagnosis of atrial fibrillation at the age of 75 years, when he developed congestive heart failure. Bradycardia associated with partial atrial standstill was detected and, the patient underwent implantation of a pacemaker at age 77. An echocardiogram revealed marked enlargement of the right atrium and moderate enlargement of the left atrium. Thus, idiopathic enlargement of the right atrium was diagnosed. He had recurrent congestive heart failure before admission to our hospital because of malnutrition and anemia. Although he was treated with high calorie intravenous infusion and blood transfusion, he died of pneumonia and heart failure. Postmortem examination revealed that the heart weighed 430 g, and there was marked dilatation of the right atrium which had an extremely thin wall. The annular circumference of the tricuspid valve was markedly dilated, 170 mm, resulting in tricuspid regurgitation. The left atrium was moderately dilated and the right and left ventricles were slightly dilated. Histologically, the free wall of the right atrium was totally replaced by fibrous tissue and atrioventricular valves did not reveal any rheumatic changes. These pathological findings were compatible with idiopathic enlargement of the right atrium. There has been no previous case report of idiopathic enlargement of the right atrium in a patient aged 80 years of age or over.

Aged↗
PubMed1998

Primary cardiac leiomyosarcoma growing rapidly and causing right ventricular outflow obstruction.

Leiomyosarcomas are extremely rare primary cardiac tumors. We report a rapidly growing primary leiomyosarcoma of the right ventricle, which obstructed the right ventricular outflow tract within one month after symptom onset in a 68-year-old man. Two-dimensional echocardiography was useful in diagnosing the extent and progression of the tumor. The tumor was surgically resected on an emergency basis, and the right ventricle and pulmonary artery were successfully reconstructed. Recurrence of the tumor on the right ventricle was observed, and the patient was overcome by sudden dyspnea and died three months after surgery.

Aged↗
PubMed1998

Regression of carotid wall thickening after corticosteroid therapy in Takayasu's arteritis evaluated by B-mode ultrasonography: report of 2 cases.

We describe 2 young Japanese female patients with active Takayasu's arteritis whose diagnosis was mainly based on the characteristic ultrasonographic finding, that is, a circumferential vascular wall thickening in common carotid arteries. Following corticosteroid therapy, serial ultrasonographic examination documented the improvement of their thickened carotid walls (in Case 1 from 1.4 to 0.5 mm after 2 months of therapy, in Case 2 from 1.5 to 0.9 mm after 9 months of therapy). These cases emphasize that ultrasonography is useful for evaluation of the therapeutic effect as well as for the diagnosis of Takayasu's arteritis in its early stage.

Adrenal Cortex Hormones↗
PubMed1997

Immunocytochemistry of extracellular matrix components in the rat seminiferous tubule: electron microscopic localization with improved methodology.

BACKGROUND: Cell-cell interactions between Sertoli, myoid, Leydig, and germ cells are thought to be essential for spermatogenesis. These cells interact with each other through the extracellular matrices (ECMs) of the testicular lamina propria, which thus may have an important function in spermatogenesis. For an understanding of the role of ECMs in spermatogenesis, it is important to investigate the molecular constitution of the testicular ECM. We examined the distribution of type IV, V, and VI collagens (Cols), laminin (LM), fibronectin (FN), and heparan sulfate proteoglycan (HSPG) in the rat testicular lamina propria. METHODS: Adult rat testes were fixed with 4% paraformaldehyde and 0.2% glutaraldehyde. Ultrathin frozen sections were made and immunolabeling was performed according to the method of Tokuyasu (1986 J. Microsc., 143:139-149). Alternatively, for preembedding immunocytochemistry, we used labeling with nanogold, followed by silver enhancement and gold toning. The tissues were then fixed with osmium and embedded in Epon (Sawada and Esaki 1994 J. Electron Microsc., 43:361-366). These specimens were examined in a JEOL JEM-100C transmission electron microscope operated at 80 kV. RESULTS: Col IV, LM, and HSPG were localized in the basement membranes of the seminiferous tubule (ST-BM) and in the BM of myoid cells. Cols V and VI, and FN were localized both in the connective tissue between the seminiferous tubule and the myoid cells (tubule-myoid connective tissue) and in the connective tissue between the myoid cells and the lymphatic endothelial cells (myoid-endothelium connective tissue). Furthermore, statistical analysis of the micrographs of immunogold labeling for Col IV, LM, and FN around the ST-BM suggested that the Col IV molecule is located uniformly in the ST-BM, whereas the LM molecule is distributed mainly in the lamina rara of ST-BM, and the FN molecule appears to be present predominantly in the tubule-myoid connective tissue. CONCLUSIONS: Distinct distribution patterns were observed for each antigen within the testicular lamina propria at the ultrastructural level. However, localization of some components was not consistent with localizations reported by others.

Animals↗
PubMed1994

Use of nanogold followed by silver enhancement and gold toning for preembedding immunolocalization in osmium-fixed, Epon-embedded tissues.

A reliable, sensitive, high-resolution method with good structural visualization for preembedding immunoelectron microscopy was proposed. The present technique involves the following processes. Immunolabeling of cryostat sections with primary antibodies and with nanogolds, silver intensification for visualization of nanogold secondary antibodies, gold-toning for stabilization of silver shells, and osmium postfixation and embedding in Epon for good structural visualization. The technique was applied to rat testis with anti-laminin and anti-fibronectin antibodies, showing that these two proteins are localized differentially in the lamina propria of the tissue.

Animals↗
PubMed1988

[Management of short bowel syndrome in infants--experience of adjunctive surgical therapy in three cases].

During the past nine years period, we managed 7 cases with short bowel syndrome resulting from massive intestinal resection in the neonatal period. Six children, aged 2 to 8 years are alive, and one died from cardiomyopathy caused by selenium deficiency at the age of one year. The carbohydrate-free milk was used for initial enteral nutrition, and the result was encouraging in 4 cases. In 3 cases in which residual small bowel varied between 6.5 to 18 cm, the enteral feeding was not incapable. These cases underwent adjunctive surgical therapy. Tailoring jejunoplasty was performed in the first case, and bowel lengthening in the second case. In both cases enteral nutrition was advanced postoperatively. The third patient who had rapid intestinal transit time underwent isoperistaltic colon interposition. Intestinal transit time was increased and enteral nutrition was advanced gradually.

Child↗
PubMed1986

Effect of psychological stress on human growth hormone response to thyrotropin-releasing hormone in normal controls.

Human growth hormone (hGH) responses to thyrotropin-releasing hormone (TRH) were investigated in normal subjects under psychological stress. Fifteen subjects (4 men and 11 women), whose ages ranged from 19 to 22 years, were studied. The mirror-drawing test (MDT) was performed to induce psychological stress. Plasma hGH and prolactin (PRL) were determined serially before, during and after the following tests: TRH alone (500 micrograms synthetic TRH i.v. bolus), MDT alone, and TRH with MDT. The changes in hGH concentrations with MDT alone were not significant. The hGH response to TRH alone also showed no remarkable change; however, hGH responses to TRH combined with MDT were significantly higher than the responses to TRH alone. PRL did not respond with MDT alone but responded significantly with the other two tests. Thus there was a divergence in hGH and PRL secretion to TRH and psychological stress. Significant increases in hGH secretion were observed only when TRH and psychological stress were combined as stimuli.

Adult↗