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Biomedical subjects

T Hoshino

Publications and source records attributed to T Hoshino.

At least 19 recordsLinked to original sources
PubMed1995

Ca(2+)-induced Ca2+ release and its activation in response to a single action potential in rabbit otic ganglion cells.

1. Ryanodine-sensitive intracellular Ca2+ release activated by Ca2+ entry was studied with fura-2 fluorescence and intracellular voltage recording techniques in rabbit otic ganglion cells. 2. The removal of extracellular Ca2+ reduced sustained, transient or oscillatory rises in intracellular Ca2+ ([Ca2+]i) induced at high extracellular K+ and abolished the [Ca2+]i oscillation in cultured neurones. 3. Ryanodine (10 microM) transiently increased [Ca2+]i and reduced the amplitude and rate of rise of the high-K(+)-induced rise in [Ca2+]i, while caffeine (5 mM) produced a few transient rises in [Ca2+]i in most cultured cells and [Ca2+]i oscillation only in one cell. 4. The two components of the slow after-hyperpolarization (AHP) of an action potential in neurones of freshly isolated ganglia were dependent on extracellular Ca2+ and abolished by Ca2+ channel blockers, Cd2+ or Co2+. 5. The late component of AHP (LAHP), but not the initial component, in 'fresh' neurones increased in area with an increase in the preceding interval, was abolished by ryanodine (10 microM) and intracellularly injected EGTA, and mimicked by intracellular injection of Ca2+. 6. A ryanodine-sensitive Ca(2+)-induced Ca2+ release thus exists, operates in response to an action potential-induced Ca2+ entry and underlies LAHP in rabbit otic ganglion cells.

Action Potentials↗
PubMed1995

Detection of MAGE-4 protein in lung cancers.

Expression of genes of the MAGE family, which encode tumor-rejection antigens recognized on HLA-AI and -Cw1601 by cytotoxic T lymphocytes (CTL), was investigated in lung cancers at the mRNA [MAGE-1, -2, -3/-6, and -4 (4a and/or 4b)] and protein (MAGE-4) levels. MAGE-1, -2, -3/-6 and -4 genes were expressed, respectively, at the mRNA level in 6, 7, 20 and 7 of 53 lung cancers (50 non-small-cell lung cancers and 3 small-cell lung cancers) by the reverse transcription-polymerase chain reaction (RT-PCR) method. Polyclonal antibody (Ab) and monoclonal antibody (MAb) against recombinant MAGE-4b protein were developed to detect MAGE-4 protein. Both the polyclonal Ab and the R5 MAb recognized a 45-kDa protein in extracts of MAGE-4 mRNA-positive lung cancers, and showed no apparent cross-reactivity with the other MAGE gene products except with MAGE-4a by immunoblot analyses and transfection experiments. MAGE-4 protein was detected on 13 of 44 (30%) lung cancers (18 to 55,989 pg/mg) by ELISA with the polyclonal Ab and R5 MAb. These 13 lung cancers consisted of 6 of 6 MAGE-4 mRNA-detectable and 7 of 38 MAGE-4 mRNA-undetectable lung cancers. Histologically, these comprised 7 of 10 squamous-cell carcinomas, 4 of 30 adenocarcinomas and 2 of 3 small-cell lung cancers. The proportions of MAGE gene-positive samples, at both the mRNA and protein levels, correlated with the size of the primary tumors and with regional node involvement. These results should provide important information on specific immunotherapy of lung cancers using MAGE gene products.

Animals↗
PubMed1995

Screening and analysis of DNA fragments that show promoter activities in Thermus thermophilus.

We have constructed a Thermus promoter probe vector pPP11 containing the promoterless heat-stable kanamycin resistance (Kmr) gene. Total DNA of T. thermophilus HB27 was randomly sheared into 100-200 bp fragments and inserted into the EcoRI site of pPP11. About 1000 clones which showed Kmr were obtained, and they were classified into three groups according to their Kmr levels. The DNA sequences of the inserted fragments of fifteen clones (Kmr levels were high for seven, medium for three and low for five clones) were determined. Kanamycin nucleotidyl transferase (KNTase) activities of the cell-free extracts of the clones were measured. Transcriptional starting points were determined for ten clones which showed a high or medium level of Kmr. Amounts of Kmr mRNA were also estimated for the ten clones. Amounts of Kmr mRNA synthesized in the clones were in good agreement, and KNTase activities were in fairly good agreement with the Kmr levels of the clones, respectively. From these results, we propose a possible consensus promoter sequence for T. thermophilus.

Base Sequence↗
PubMed1995

Frequency of exon 15 missense mutation (442D:G) in cholesteryl ester transfer protein gene in hyperalphalipoproteinemic Japanese subjects.

Cholesteryl ester transfer protein (CETP) transfers cholesteryl ester from high density lipoprotein (HDL) to apo B-containing lipoproteins. The hyperalphalipoproteinemia caused by CETP deficiency is fairly common in Japan and one of the most common mutations in the CETP gene is the splicing defect of the intron 14, the allelic frequency of which has been shown to be 0.0049 in the Japanese general population. Recently, we have reported a missense mutation in exon 15 of the CETP gene (442D:G), showing a dominant effect on the CETP activity and HDL-cholesterol level. In the current study, we determined the frequency of this new mutation in Japanese hyperalphalipoproteinemic (HDL-cholesterol > or = 100 mg/dl) subjects. A rapid and easy screening method for this new mutation was developed using a polymerase chain reaction (PCR)-mediated site-directed mutagenesis. Among 117 Japanese hyperalphalipoproteinemic subjects (HDL-cholesterol; 116.7 +/- 16.5 mg/dl, mean +/- S.D.) without the intron 14 splice defect, three homozygotes (2.5%) and 34 heterozygotes (29.1%) were found to have the 442D:G mutation. The relative allelic frequency of this mutation was calculated to be 0.17. One of the homozygotes for the 442D:G mutation was the patient previously described by us as having hyperalphalipoproteinemia with corneal opacity and coronary heart disease. This was the first reported subject homozygous for the CETP deficiency who also demonstrated atherosclerotic symptoms. In homozygous subjects, CETP activity ranged from 37% to 62% of the normal value, which was consistent with the results obtained from the transient expression experiment previously reported; however, the specific activity of CETP was not as low as expected.(ABSTRACT TRUNCATED AT 250 WORDS)

Asian People↗
PubMed1995

One-step sandwich enzyme immunoassays for human C4b-binding protein (C4BP) and protein S-C4BP complex using monoclonal antibodies.

C4b-binding protein (C4BP), a regulatory component in the complement system, binds to an anticoagulant vitamin K-dependent plasma protein S (PS) which acts as a cofactor of activated protein C. We raised monoclonal antibodies against C4BP and PS, and developed two different one-step sandwich enzyme immunoassay (EIA) systems for human total C4BP (assay A) and PS-C4BP complex (assay B) by using a solid phase monoclonal antibody and a horseradish peroxidase-labeled monoclonal antibody (Fab'). The reaction time of the assay was 45 min in both EIA systems: 30 min for the immunoreaction and 15 min for the color reaction. The sensitivities were 12 and 20 mg/l in assays A and B, respectively. Linearity was obtained between 31 and 500 mg/l in both EIA systems. Assay A could detect both uncomplexed C4BP and PS-C4BP complex with equal efficiency so that total C4BP level was not affected by PS. The levels of total C4BP and PS-C4BP complex were found to significantly increase in sera from patients with membranous nephropathy and decrease with liver cirrhosis in comparison with the levels in normal subjects. On the other hand, a difference in the total C4BP and PS-C4BP complex levels was not shown between IgA nephropathy and normal subjects. Affinity column analysis and difference of total C4BP and PS-C4BP complex levels showed that most of C4BP in sera exists as PS-C4BP complex.

Animals↗
PubMed1995

Heat shock enhances the susceptibility of tumor cells to lysis by lymphokine-activated killer cells.

OBJECTIVE: To determine whether heat-treated thyroid cancer cells augment the susceptibility of target cells to lysis by autologous lymphokine-activated killer cells. DESIGN: Peripheral blood lymphocytes from patients with thyroid cancer were incubated with recombinant interleukin 2 (100 U/mL) for 7 days, and thyroid cancer cells obtained from surgical specimens were heated at 44 degrees C for 20 minutes and incubated at 37 degrees C for 18 hours before performing the radioactive chromium Cr 51 release assay. RESULTS: The susceptibility of heat-treated thyroid cancer cells to lysis by autologous and allogeneic lymphokine-activated killer cells was significantly greater than that of untreated tumor cells. The mechanism of enhanced susceptibility was unclear. However, the effect depended on de novo protein synthesis, because inhibition of RNA synthesis by dactinomycin completely abolished the heat-enhanced susceptibility of tumor cells. CONCLUSION: Immunotherapy combined with hyperthermia may be useful in management of thyroid cancer.

Adenocarcinoma, Papillary↗
PubMed1995

A new retinacular ligament and vein of the human temporomandibular joint.

In the human temporomandibular joints of 14 Japanese cadavers, we observed a new retinacular ligament that connected to the retrodiskal pad posterolaterally and was accompanied by a vein draining the retrodiskal pad. This retinacular ligament originated from lateral to posterolateral part of the joint. The origin included the articular tubercle of the zygomatic process of the temporal bone. The ligament descended along the mandibular ramus to insert into the fascia of the masseter muscle at the mandibular angle. The vein originated from the venous plexus in the retrodiskal pad and ran parallel to the retinacular ligament, giving off branches to the retromandibular, transverse facial, and superfacial temporal veins. There were no remarkable differences in the size of the retinacular ligaments among individuals as well as between the left and right sides. The retinacular ligament had firm fibrous connections with the posterolateral part of the retrodiskal pad, where the external fibrous membrane of the articular capsule was lacking. These findings suggest that the retinacular ligament and its accompanying vein function together to maintain blood circulation during jaw movement and may also be related to the development of occlusal disorders.

Adult↗
PubMed1995

In vitro cytotoxicities and in vivo distribution of transferrin-platinum(II) complex.

In vitro cytotoxic studies of protein-bound cis-diamminedichloroplatinum(II) (CDDP) against human epidermoid carcinoma A431 cells showed that transferrin (Tf)-bound CDDP (Tf-Pt, Pt/Tf 7:1 mol/mol), and human serum albumin (HSA)-bound CDDP (HSA-Pt, Pt/HSA 7:1 mol/mol) exerted antiproliferating activities with IC50 values of 7.2 and 85 microM, respectively. Tf-Pt inhibited the binding of 0.2 nM 125I-labeled human diferric transferrin (hTf(Fe)2) to A431 cells with a inhibition constant (Ki) of 42 nM, whereas HSA-Pt did not. In vivo distribution studies showed that hTf(Fe)2, the Ki of which was 5.3 nM to mouse melanoma B16 cells, was eliminated from plasma biexponentially in the B16-bearing and control mice after intravenous injection at a dose of 87 mg/kg, and AUCplasma values were 29 and 39 mg.h/mL, respectively. In the B16-bearing mice the AUCtumor was 5.6 mg.h/mL, while the AUCs of liver, kidney, and spleen were not distinguishable between the B16-bearing and control mice. Subsequently Tf-Pt (Pt/Tf 3:1 mol/mol) and free CDDP solution were administered intravenously to the B16-bearing mice. The systemic circulation of Pt was significantly prolonged by the administration of the complex. In conclusion, Tf could be a promising carrier protein for the transport of Pt to tumors.

Animals↗
PubMed1995

Immunohistochemically defined lymphocyte function-associated antigen 1 (LFA-1) on an adenocarcinoma cell line is a distinct molecule from LFA-1 on leukocytes.

We previously reported that the immunohistochemically defined LFA-1 antigen (LFA-1-like antigen) was expressed on various exocrine tissues uninvolved with tumors in patients with malignant diseases using LFA-1 alpha-specific monoclonal antibodies (mAb) 2F12 and HVS6B6. In this study we investigated differences at the molecular level between LFA-1 on leukocytes and LFA-1-like antigen on MKN45.16, a subline derived from an adenocarcinoma line MKN45 that expresses a high amount of LFA-1-like antigen. LFA-1-like antigen was reactive to mAb 2F12 or HVS6B6, but not to any of the other five different LFA-1 alpha (CD11a)-specific or four LFA-1 beta (CD18)-specific mAb. mAb 2F12 immunoprecipitated a 200-kDa membrane protein (LFA-1-like antigen) from MKN45.16 cells, whereas it precipitated 180-kDa (LFA-1 alpha) and 95-kDa (LFA-1 beta) proteins from a monocytic cell line (THP-1) under both nonreducing and reducing conditions. The molecular difference was confirmed further by N-glycanase treatment of the immunoprecipitates. The isoelectric point of LFA-1-like antigen was 6.0, whereas those of LFA-1 alpha and LFA-1 beta were 6.0 and 4.7, respectively, by two-dimensional gel electrophoresis. Expression of LFA-1 alpha gene on MKN45.16 cells was not detected at the mRNA level by six different sets of LFA-1 alpha-specific oligonucleotides and reverse transcription-polymerase chain reaction. These results indicated that LFA-1-like antigen on an adenocarcinoma cell line was a distinct molecule from LFA-1 on leukocytes.

Adenocarcinoma↗
PubMed1995

Electron-microscopic and immunohistochemical studies of Langerhans cells and Thy-1-positive cells in mouse tongue epithelium subjected to local hyperthermia.

Local hyperthermia via skin has been used to treat cancer but may suppress local immune responses as a side-effect. To examine effects of heat on immunologically responsive cells in oral mucosa, mouse tongues were heated by an implant system at 43 degrees C for 20 min. The densities of Langerhans cells and Thy-1-positive cells rapidly increased within 3 h after the treatment, then returned to a normal level after 7 days. Electron microscopy confirmed that Langerhans cells in the tongue epithelium formed clusters with lymphocytic cells, suggesting an active response to the hyperthermia.

Adenosine Triphosphatases↗
PubMed1995

Osteoplastic changes in attic cholesteatoma.

Eighty-nine cases of attic type cholesteatoma were operated on during a three and a half-year period. Of these, eight cases were characterized by bony tissue proliferation at the aditus ad antrum or mastoid antrum. Sex, age, and hearing levels were not significant in these cases. Bony fixation of the incus and the malleus was seen in six cases. Bony tissue blocked further expansion of attic cholesteatoma at the aditus in four cases, narrowed the epithelial tract to the antrum in two cases, and completely separated the cholesteatoma into two cholesteatomas in two cases. Infectious stimuli, at an early stage of the disease, might stimulate such osteoplastic activity at the aditus. Axial CT scans give useful information regarding structure before surgery.

Adult↗
PubMed1995

Spontaneous production of various cytokines except IL-4 from CD4+ T cells in the affected organs of sarcoidosis patients.

We investigated surface antigens and spontaneous cytokine production of T cells from bronchoalveolar lavage fluid (BALF) and aqueous humor (AH) from pulmonary sarcoidosis patients for a better understanding of the role of T cells in granuloma formation. The levels of CD3, CD11b, and CD28 antigen expression on freshly isolated T cells in the BALF of patients were significantly lower than those in peripheral blood lymphocytes (PBL) of either sarcoidosis patients or healthy donors (HD). In contrast, the levels of CD80 (B7/B7-1) and CD86 (B70/B7-2) antigen expression were significantly higher on these T cells and alveolar macrophages in the BALF of patients. Fifty-three T cell clones (TCC) established from the BALF and AH of the three sarcoidosis patients displayed primarily either CD4+ CD11b+ CD28+ or CD4+ CD11b- CD28- phenotypes. Most (61-90%) of these TCC spontaneously produced greater amounts of IL-1 alpha, IL-10, tumour necrosis factor (TNF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) than did TCC from the PBL from sarcoidosis patients or HD (P < 0.05). Interferon-gamma (IFN-gamma), IL-6, and IL-2, but not IL-4, were also produced by 40-48% of these TCC. These results suggest that CD4+ T cells of the affected organs of sarcoidosis patients are activated and involved in the immunopathogenesis of sarcoidosis through production of various cytokines.

Adult↗
PubMed1995

Cloning and nucleotide sequencing of the membrane-bound L-sorbosone dehydrogenase gene of Acetobacter liquefaciens IFO 12258 and its expression in Gluconobacter oxydans.

Cloning and expression of the gene encoding Acetobacter liquefaciens IFO 12258 membrane-bound L-sorbosone dehydrogenase (SNDH) were studied. A genomic library of A. liquefaciens IFO 12258 was constructed with the mobilizable cosmid vector pVK102 (mob+) in Escherichia coli S17-1 (Tra+). The library was transferred by conjugal mating into Gluconobacter oxydans OX4, a mutant of G. oxydans IFO 3293 that accumulates L-sorbosone in the presence of L-sorbose. The transconjugants were screened for SNDH activity by performing a direct expression assay. One clone harboring plasmid p7A6 converted L-sorbosone to 2-keto-L-gulonic acid (2KGA) more rapidly than its host did and also converted L-sorbose to 2KGA with no accumulation of L-sorbosone. The insert (25 kb) of p7A6 was shortened to a 3.1-kb fragment, in which one open reading frame (1,347 bp) was found and was shown to encode a polypeptide with a molecular weight of 48,222. The SNDH gene was introduced into the 2KGA-producing strain G. oxydans IFO 3293 and its derivatives, which contained membrane-bound L-sorbose dehydrogenase. The cloned SNDH was correctly located in the membrane of the host. The membrane fraction of the clone exhibited almost stoichiometric formation of 2KGA from L-sorbosone and L-sorbose. Resting cells of the clones produced 2KGA very efficiently from L-sorbosone and L-sorbose, but not from D-sorbitol; the conversion yield from L-sorbosone was improved from approximately 25 to 83%, whereas the yield from L-sorbose was increased from 68 to 81%. Under fermentation conditions, cloning did not obviously improve the yield of 2KGA from L-sorbose.

Acetobacter↗
PubMed1995

Human histocompatibility leukocyte antigen-DR and heat shock protein-70 expression in eye muscle tissue in thyroid-associated ophthalmopathy.

To investigate the expression and localization of human leukocyte antigen (HLA)-DR and heat shock protein-70 (HSP-70) in orbital tissue from patients with thyroid-associated ophthalmopathy (TAO), we carried out an immunohistochemical study using anti-HLA-DR and anti-HSP-70 monoclonal antibodies and a streptavidin-biotinperoxidase detection system. Eye muscle tissues were obtained at surgery from 38 patients with TAO and 8 control subjects. HLA-DR expression on eye muscle cells was demonstrated in orbital tissue from 2 of 3 untreated patients and 2 of 35 patients who had been treated with orbital irradiation or corticosteroids, in all of whom lymphocytic infiltration was also demonstrated. HLA-DR was not detected on eye muscle cells from 8 normal controls studied. HLA-DR was expressed on endothelial cells and interstitial cells from almost all patients with TAO and all 8 control subjects. HSP-70 was detected in eye muscle cells from 31 of the patients with TAO, including all 3 untreated patients, and 3 of the controls. Although the degree of HSP-70 expression did not correlate with the severity of the ophthalmopathy, significant expression of HSP-70 in eye muscle cells was more often demonstrated in patients with eye disease of short duration (83%) than in those with disease of longer duration (33%). These results support the notion that eye muscle fiber is an important target of the orbital autoimmune reactions that characterize TAO.

Adult↗
PubMed1995

Inhibitory activity of 8-azadecalin derivatives towards 2,3-oxidosqualene:lanosterol cyclases from baker's yeast and pig's liver.

The inhibitors of 2,3-oxidosqualene:lanosterol cyclase were investigated by comparative studies between pig's liver and Baker's yeast. The fundamental skeleton of the inhibitors was 8-azadecalin. To the nitrogen atom, an isoprenoid-like chain [nerylacetone (Z-form), geranylacetone (E-form) or its hydrogenated form] was attached by the reaction of reductive amination with NaCNBH3. Among the three forms, the Z-isomer was the most potent inhibitors toward both the pig's liver and yeast cyclases. To examine the effect of carbon chain length (lipophilicity), various fatty acids (C6-C18) were appended to the 8-azadecalin derivatives. Strong inhibitory activity was observed for those compounds having carbon chains around C12. Interestingly, the amide compounds (not the carbocationic intermediate) exhibited remarkably strong inhibition toward the liver cyclase, whereas they had an insignificant effect on the yeast cyclase (about 10(2)-fold less active). The yeast cyclase needed the amine functionality (carbocationic intermediate), which was prepared by using LiAlH4 from the corresponding amides, to exhibit potent inhibition. We found that N-dodecyl-8-aza-4,4,10 beta-trimethyl-trans-decal-3 beta-ol (7i) was the most potent inhibitor (IC50 = 1 microM) toward the yeast cyclase amongst any known material. Kinetic studies showed that the inhibition pattern was dependent only on whether the side chains on the 8-azadecalin were linear or branched; the compounds having isoprenoid-like chains were non-competitive inhibitors, while those having linear hydrocarbon chains (amides or amines) were competitive inhibitors.

Animals↗
PubMed1995

[Pain management in advanced pediatric cancer patients--a proposal of the two-step analgesic ladder].

Pain treatment for 17 pediatric cancer patients in our institution was evaluated and disirable cancer pain management for children was discussed. Most of the patients (aged 1-17 years) suffering severe pain for about one month were in the advanced stage of the malignant diseases (e.g. leukemia). The pain etiology was mostly tumor-associated while therapy-related pain accounted for 23.5%. These pains were treated with NSAIDs or pentazocine before the consultation with inadequate relief. Oral morphine sulfate or continuous intravenous morphine chloride was administered to 16 patients with successful pain relief and side effects such as nausea (52.9%) and drowsiness (41.2%). It took 5.5 days on average until adequate pain control methods were determined. It is known that most NSAIDs frequently used for pediatric pain possibly cause adverse effects such as platelet dysfunction or mucous membrane injury with a suppository, which could lead to a fatal disorder in clinically ill pediatric cancer patients. Moreover sufficient doses for the pain relief are not necessarily given to the pediatric patients because of a limit to the dosage of NSAIDs. The period of pediatric cancer pain in which the patient require a methodical treatment and receive benefit from pain relief is relatively short in the advanced stage, not to mention the early stage in which chemotherapy is efficacious against cancer disease itself. Therefore, to obtain effective pain control within a short time, the authors propose the pain management for advanced pediatric cancer patients by the two-step analgesic ladder prescribing weak or strong opioid analgesics first, adapted from the three-step ladder of the WHO Cancer Pain Relief, 1986.

Adolescent↗