Biomedical subjects

T Shinohara

Publications and source records attributed to T Shinohara.

At least 145 records · Page 8Linked to original sources

PubMed1997

[Ossicular vibration changes associated with pressure changes in inner ear and cerebrospinal fluid in guinea pigs].

The effects of increase in the inner ear and cerebrospinal fluid (CSF) pressures on the vibration of the ossicular chain were studied in guinea pigs by using a laser doppler vibrometer. Velocity of the malleus umbo and that of the incus long crus in response to a constant sound stimulus of 90dB SPL at the tympanic membrane were measured at 13 frequencies between 0.125 kHz and 10 kHz. Loading pressures to the inner ear and the CSF were adjusted by changing the height of a saline bottle hooked up to the respective site by a 24G Teflon catheter. The pressure was monitored with a pressure transducer placed in the catheter. Positive and negative pressure loads to the inner ear decreased the velocity of the umbo at low and high frequencies. The maximum change was 4.7 dB at 0.125 kHz with a positive pressure load of 400 mmH2O. Similar results were obtained for the umbo and the long crus by a positive pressure load to the CSF, with the exception that the umbo velocity showed no change at higher frequencies. These results suggest that the inner ear and CSF pressure changes affect not only the function of the organ of Corti but also the vibration of the ossicular chain. These changes occurred mainly at lower frequencies.

Animals↗

PubMed1997

[Successful pulmonary thromboendarterectomy in a patient with chronic pulmonary thromboembolism].

A 63-year-old patient had been diagnosed with angina pectoris for 5 months and came to us complaining of progressive exertional dyspnea. Echo cardiography showed remarkable pulmonary hypertension and we were prompted to do cardiac catheterization. The catheterization showed the pressure of the main pulmonary artery (PA) as 84/14 (36) mmHg and PA angiography showed a massive embolus in the right main PA. Chest computed tomography and lung perfusion scintigraphy were also compatible with pulmonary embolism. The patient had been treated with anticoagulant for 1 month, but he was not doing well. We decided to remove the embolus surgically. In a median sternotomy, a cardiopulmonary bypass was established with ascending aortic and two caval cannulae. During cooling, the right PA was mobilized within the pericardial reflection. An incision was made in the right PA. An organized thrombus was located at the central PA and extended to the distal segmental PA. Thromboendarterectomy was carried out carefully. To obtain a better operative view, circulatory arrest was introduced intermittently. The left PA was opened and the organized thrombus, located at the bifurcation between the upper and lower branch, was removed. Post-operative PA angiography showed remaining thrombus in the right lower PA, but the pressure of the main PA fell to 27/12 (18) mmHg. Pulmonary thromboendarterectomy by median sternotomy with the aid of deep hypothermia and circulatory arrest was useful to remove the thrombus in the bilateral PA, and to obtain good hemodynamic and symptomatic results.

Endarterectomy↗

PubMed1997

[Chronic myelomonocytic leukemia developed 7 years after the onset of idiopathic thrombocytopenic purpura like syndrome].

A 55-year old woman admitted to our hospital with bleeding tendency. She was diagnosed as having idiopathic thrombocytopenic purpura (ITP) by the platelet count 4.8 x 10(4)/microliter, Platelet associated IgG (PAIgG) 88.5 ng/10(7) cells, and an increase of megakaryocyte (81/microliter) of the sternal bone marrow. No obvious dysplasia of three lineages was observed. Because she did not respond to corticosteroid and gamma globulin, she was undertaken splenectomy 3 years after the diagnosis and the platelet count had been kept more than 3.0 x 10(4)/microliter during the following 2 years. After 7 years from the onset of ITP, she was admitted because of leukocytosis (16500 microliters with 8% monocytes) and thrombocytopenia (1.9 x 10(4)/microliter) with bleeding tendency. Hypercellular bone marrow with dysplasia of three lineages such as dyserythropoiesis, Pelger like nucleus, and micromegakaryocyte was observed. The chromosomal analysis presented 46XX, del (20) (q11.2) in all (50/50) cells. She was diagnosed as having chronic myelomonocytic leukemia (CMMoL). This is a difficult case in which it was distinguish ITP from refractory thrombocytopenia, a subtype of myelodysplastic syndrome. We reexamined and found some morphological abnormalities at diagnosis, suggesting that it might be preleukemic stage.

Blood Cell Count↗

PubMed1997

Induction of rat hepatic cytochrome P450 2B subfamily by azidophenobarbital, as a possible photoaffinity probe for the putative phenobarbital receptor: comparative study with modified phenobarbitals with different functional groups.

To study the specific target to which phenobarbital (PB) binds, resulting in the induction of cytochrome P450, we prepared two azido-PBs (AZPBs) as photoaffinity ligands. The azido substituent was introduced at the para- or meta-position of the PB aromatic ring. In this study, we estimated the utility of these compounds by examining their inducing activities in vivo in rats. Induction was assessed by immunoblotting with anti-CYP2B1/2 antibody and measuring testosterone-metabolizing activity, using hepatic microsomes. Administration of p-AZPB to rats increased hepatic CYP2B1/2 protein and testosterone 16beta-hydroxylase activity, although the effects were less than those of unmodified PB. m-AZPB showed no effect in the induction of CYP2B1/2. To assess the specificity of the effects of substituents, we compared the inducing activities of p/m-nitro-PBs, p/m-amino-PBs, and p/m-hydroxy-PBs with those of AZPBs. The results showed that p-nitro-PB, m-amino-PB, and p-hydroxy-PB were also potent inducers for CYP2B1/2, with lower activity than that of unmodified PB, whereas the other three isomers had no effect. These results suggest that 1) the absence of any substituents on the aromatic ring of PB is needed for maximal inducing activity and 2) substitution at the meta-position of the PB aromatic ring tends to reduce effectiveness as an inducer more than does substitution at the para-position. Because p-amino-PB and p-acetylamino-PB, the minor and major metabolites of p-AZPB, respectively, were without effect in the induction of CYP2B1/2, the effect of p-AZPB was considered to be due to the unchanged compound itself. The present study demonstrates that, based on the weak but positive ability to induce CYP2B1/2, p-AZPB may be a useful tool for identifying the putative PB receptor.

Animals↗

PubMed1997

Model of malignant pleural effusion of human lung adenocarcinoma in SCID mice.

Malignant pleural effusion (PE) is a frequent problem in lung cancer. In this study, we established a model of malignant PE of human adenocarcinoma cells, PC-14, in SCID mice. Intravenously injected PC-14 cells formed colonies in the lungs as early as week 4 after tumor inoculation, and produced bloody PE in all recipient SCID mice by week 8. Pretreatment of SCID mice with anti-mouse IL-2 receptor beta chain antibody (TM-beta 1) to deplete natural killer (NK) cells markedly promoted the production of bloody PE and metastases to multiple organs, such as the lungs, liver, kidneys, and lymph nodes 4 weeks after tumor inoculation. Histological studies indicated that PC-14 cells formed colonies in the lungs, and then invaded the pleura and spread to the pleural cavity. To establish cell lines with a high potential to produce PE, we harvested PE, expanded the tumor cells in vitro, and injected them into SCID mice again. By four in vivo selection cycles in this way we obtained PC-14-PM4 cells, which produce lung metastases and PE earlier than PC-14 cells. The survival of SCID mice inoculated with PC-14-PM4 cells was significantly shorter than that of mice inoculated with PC-14 cells. The expressions of adhesion molecules, such as CD44, CD49d, ICAM-1, and MHC class I, on PC-14-PM4 cells tended to increase compared with PC-14 cells. These changes of adhesion molecules seem to be one of possible mechanisms involved in higher metastatic potential of PC-14-PM4 cells. PE models with PC-14 and PC-14-PM4 cells should be useful for biological and preclinical studies on malignant PE produced by human lung cancer.

Adenocarcinoma↗

PubMed1996

Common reabsorption system of 1,5-anhydro-D-glucitol, fructose, and mannose in rat renal tubule.

1,5-Anhydro-D-glucitol (AG) is a major polyol, 99.9% of which is reabsorbed by the kidney. However, such reabsorption is inhibited by competition with glucose excreted in excess, i.e., glucosuria. Under such conditions, AG is excreted into the urine. We administered various types of sugars to rats by continuous intravenous infusion for two hours to evaluate the competition between AG and these sugars for renal reabsorption in vivo. The reabsorption of AG was significantly inhibited by competition with fructose and mannose. The excretion of AG in the 120 min after a load of 3.64 mmol of fructose was 1.99 +/- 0.33 mumol, that after 3.64 mmol of mannose loading was 2.34 +/- 0.43 mumol. These levels were comparable to the AG excretion observed after the administration of the same amount of glucose (3.87 +/- 0.61 mumol). No competition was observed with sucrose, xylose, myoinositol or galactose. The reabsorption of fructose and mannose was significantly inhibited by the presence of AG (P < 0.001) after a mixed load. Results suggest that AG is reabsorbed in the renal tubule by an AG/fructose/mannose-common transport system that is distinct from the major glucose reabsorption system. These findings may help to clarify the specific transport systems for various sugars in the renal tubule, as well as their physiological importance.

Absorption↗

PubMed1996

Epidermal growth factor can replace thymic mesenchyme in induction of embryonic thymus morphogenesis in vitro.

The thymus is surrounded by a thin layer of mesenchyme and the epithelial-mesenchymal interaction is known to be essential for the thymus development. To clarify the roles of mesenchyme in the thymus lobule formation that occurs around embryonic days 14-15 in vivo, we set up a three-dimensional organ culture system. The epithelium of embryonic day 14 thymic primordium was separated from the mesenchyme and cultured in Matrigel (reconstituted basement membrane). Addition of the mesenchyme to a chamber separated by a membrane filter induced the lobule formation of the thymic epithelium in vitro. We found that epidermal growth factor (EGF) can replace the mesenchyme for lobulation of the embryonic thymus in vitro. Among other growth factors tested, only transforming growth factor (TGF)-alpha was as effective as EGF, in agreement with the fact that EGF and TGF-alpha bind to the same receptor. These results suggest that EGF or its family members may be involved in morphogenesis and differentiation of the thymus gland epithelium, although we cannot exclude the possibility that other unknown factors are required in vivo.

Amino Acid Sequence↗

PubMed1996

Porcine S-antigen: cDNA sequence and expression in retina, ciliary epithelium and iris.

cDNA clones encoding S-antigen (arrestin) were isolated from the expression library constructed from porcine retina and sequenced. The 1490 base pair fragment contained a 1215 base pair open reading frame. From the nucleotide sequence, an amino acid sequence consisting of 405 residues was deduced and a molecular mass of 45,102 daltons was calculated. In order to determine whether the S-antigen mRNA transcript was expressed in anterior eye tissues, mRNA from ciliary non-pigmented epithelial cells and pigmented epithelial cells and iris was analysed by the reverse transcription polymerase chain reaction (PCR) using primers taken from sequences flanking the coding and non-coding regions of retinal S-antigen. Sequence analysis of the expected 611 base pairs in the 5' region and 672 base pairs in the 3' region of DNA fragments indicated that an identical mRNA for S-antigen was expressed in the anterior tissues examined. To investigate the in situ expression of S-antigen mRNA, 35S-labeled sense and antisense RNA probes were synthesized from the cDNA to label frozen sections of retina, ciliary body and iris and the treated sections were examined by autoradiography. The antisense probe labeled the layer between retinal pigmented epithelium and the outer nuclear layer of the retina, ciliary epithelium, and iris epithelium. From the results of sequencing PCR products and in situ hybridization, we concluded that, in porcine eye, the mRNA for S-antigen is expressed not only in the retina but also in the anterior tissues such as the ciliary epithelium and iris epithelium.

Animals↗

PubMed1996

Expression of vascular endothelial growth factor in human myocardial infarction.

To define mechanisms that may influence collateral circulation and angiogenesis, we investigated vascular endothelial growth factor (VEGF) mRNA expression in human hearts. In non-ischemic human hearts, VEGF mRNA was not detected in vessels, but was found in cardiomyocytes. In hearts with myocardial infarction, the intensity of the VEGF signal was much higher in smooth muscle cells of arterioles adjacent to necrosis and in infiltrating macrophages than in myocytes around the site of the necrosis. This study suggests that levels of VEGF expression are high in smooth muscle cells and macrophages around infarcted areas after myocardial infarction and that VEGF may play a role in promoting collateral circulation and angiogenesis in human ischemic hearts.

Aged↗

PubMed1996

Cellular immune responses of patients with juvenile chronic arthritis to retinal antigens and their synthetic peptides.

The objective of this study was to determine the proliferative responses of peripheral blood lymphocytes of ocular antigens like retinal S-antigen, peptides M and G of S-antigen, yeast histone H3 peptide 106-121 homologous to peptide M and peptide R16 of interphotoreceptor retinoid binding protein (IRBP) in children with juvenile chronic arthritis (JCA). We have studied the in vitro proliferative response of peripheral blood lymphocytes from 41 patients with JCA (10 with and 31 without uveitis) and 23 healthy controls against the above antigens. The responders were retested after 1 or 6 months. Fifty (5/10) and 9.7% (3/31) of JCA patients with and without uveitis, respectively, responded (stimulation index > 3) to S-antigen or one of its peptide listed above or yeast histone H3 peptide or R16 of IRBP. None of the healthy controls responded to any of these antigens. The difference in the frequency of responders (SI > 3) between JCA associated with uveitis and healthy controls was statistically significant (p = 0.001). Similarly, the difference between JCA with and without uveitis was also significant (p = 0.013). Our findings suggest that these antigens may have a role in the pathogenesis of uveitis in a subset of patients with JCA.

Amino Acid Sequence↗

PubMed1996

Apoptosis and proliferation in gastric carcinoma: the association with histological type.

We examined apoptosis in 33 gastric carcinomas using the terminal deoxynucleotydil transferase mediated dUTP-digoxigenin nick end labelling technique (TUNEL). Of the tumours, nine were well-differentiated, 13 moderately differentiated and 11 poorly differentiated. In addition, we also analysed MIB-1, a cell proliferation antigen. Morphologically, apoptotic tumour cells were more frequently observed in well-differentiated tumours. In addition, apoptotic signals of the TUNEL method were seen even in the nuclei of tumour cells which did not show apoptosis. The nick end labelling index was 51.0 +/- 26.3 in the well-differentiated and moderately differentiated tumours and 28.0 +/- 18.8 in poorly differentiated tumours. The mean of apoptotic body index and nick end labelling index were both significantly higher in well-differentiated and moderately differentiated tumours than in the poorly differentiated type (P < 0.0001, P = 0.008). The MIB-1 labelling index and higher in poorly differentiated tumours than in the well-differentiated or moderately differentiated tumours, and labelled cells were more numerous in the superficial region than in the middle and deep regions of tumours. No apparent correlation was found between the nick end labelling index and the MIB-1 labelling index. The high number of apoptotic cells (the high Nick end labelling index) and low proliferation potentiality (the low MIB-1 labelling index) in well-differentiated gastric carcinomas may thus be related to their natural tendency to demonstrate slow growth.

Adenocarcinoma↗

PubMed1996

Transduction of the macrophage colony-stimulating factor gene into human multidrug resistant cancer cells: enhanced therapeutic efficacy of monoclonal anti-P-glycoprotein antibody in nude mice.

To develop a therapeutic modality for overcoming multidrug-resistant (MDR) cancer with anti-MDR1 antibody, we examined the effect of macrophage colony-stimulating factor (M-CSF) gene transfection into MDR AD10 cells on therapy of MDR cancer with anti-MDR1 antibody (MRK17) in nude mice. MDR human ovarian cancer (AD10) cells were transduced with the human M-CSF gene inserted into an expression vector to establish gene-modified cells capable of producing low (ML-AD10), intermediate (MM-AD10) nd high (MH-AD10) amounts of M-CSF. Systemic administration of MRK17 resulted in significant dose-dependent inhibition of subcutaneous growth of ML-AD10 tumors. In contrast, systemic administration of recombinant M-CSF in combination with MRK17 did not augment the therapeutic efficacy of MRK17 alone, but rather promoted the growth of the parent AD10 cells. To test the efficacy of in vivo M-CSF gene therapy combined with antibody, we mixed the parent AD10 cells with MH-AD10 cells producing a large amount of M-CSF, and inoculated the mixed cells subcutaneously. Treatment with MRK17 inhibited growth of the mixed cells more than that of the parent cells alone. Thus, combined therapy with anti-MDR1 mAb and M-CSF gene modification of MDR cancer cells may provide a new immunotherapeutic modality for overcoming MDR in humans.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1996

Cortical dysgenesis in a patient with Turner mosaicism.

In a patient with Turner mosaicism who had mental retardation, epilepsy and cerebellar ataxia, MRI showed cerebellar atrophy and a bizarre cortical dysgenesis of the cerebrum, which was considered to comprise a mixture of relatively normal gyri and structures resembling pachygyria and lissencephaly. The karyotype of the patient was 45,X/47,XXX, but the brain dysgenesis could not be explained solely on the basis of this mosaicism, which is rarely associated with a gross abnormality in brain pathology. Abnormality of the X chromosome seems to have some potential for inducing cortical dysgenesis, and this case may be partially attributable to an abnormal locus on the X chromosome.

Adult↗

PubMed1996

Expression of multiple classes of the nuclear factor-1 family in the developing human brain: differential expression of two classes of NF-1 genes.

Nuclear factor-1 (NF-1) is a multifunctional protein that participates in both transcription and replication. NF-1 proteins exist as a family of proteins that share some common structural and functional features but also demonstrate organ and cell type specific expression. Based upon these characteristics, the family of NF-1 proteins is divided into four classes, A, B, C and D. Several NF-1 binding sites have been identified in the regulatory sequences of the human polyomavirus, JCV, which multiplies most efficiently in glial cells derived from human fetal brain. Nuclear proteins from these cultures bind specifically to these NF-1 sites. It is not known, however, which member(s) of the NF-1 family is expressed in cells susceptible to JCV infection. We have examined glial cells as well as HeLa cells, which are not permissive to JCV, for NF-1 expression. By RT-PCR analysis, all four classes of NF-1 are expressed in human fetal glial cells and HeLa cells. However, by Northern analysis the expression of class D gene is much higher in the glial cells than HeLa cells. Expression of the class C gene, first identified in HeLa cells as NF-1/CTF1, is barely detectable in glial cells but highly expressed in HeLa cells. The screening of cDNA libraries from two early human brain tissues resulted in the identification of a number of clones which appear to be related and belong to a single class of the NF-1 family, class D. Nucleotide sequence of one clone, designated NF-1/AT1, confirms this. The NF-1/AT1 protein was overexpressed in E coli and found to bind specifically to an NF-1 probe by gel shift analysis. Southern analysis of human fetal glial cells indicates that the NF-1/AT1 gene, class D, is derived from a different gene than NF-1/CTF1. These results suggest the possibility that genes or viruses, like JCV, which use NF-1 for their expression in human brain derived cells may preferentially use the NF-1 class D protein.

Amino Acid Sequence↗

PubMed1996

[Expression of decay-accelerating factor on CD8-positive lymphocytes as an index of aging and of host defense function].

Decay-accelerating factor (DAF) is a membrane glycoprotein that prevents complement activation on blood cells. Among CD8+ T cells, DAF-negative cells can be distinguished from DAF-positive cells. We computed the proportion of DAF-negative CD8+ T cells in the peripheral blood of 59 normal healthy subjects, 27 to 93 years old, and analyzed the differences between subjects of different ages. The proportion of CD8+ T cells that were DAF-negative correlated significantly and positively with age. We also studied these lymphocytes in patients with cerebrovascular dementia, Alzheimer's dementia, cancer, rheumatoid arthritis and systemic lupus erythematosus. The proportion of CD8+ T cells that were DAF-negative did not correlate significantly with age in patients with cerebrovascular dementia, Alzheimer's dementia or cancer, but it correlated significantly and positively with age in patients with rheumatoid arthritis and in those with systemic lupus erythematosus. Therefore, healthy subjects and patients with various diseases can be classified according to age and to the proportion of CD8+ T cells that are DAF-negative. This proportion can then be used as an index of aging and of host defense function.

Adult↗

PubMed1996

[Blood patch therapy of the perilymphatic fistulas--an experimental study].

Blood patch is a therapeutic procedure that uses a perilymphatic fistula to repair an inner ear window rupture by filling the tympanic cavity with autologous blood. The experimental study was conducted in 13 guinea pigs. Autologous blood or commercially available fibrin glue was poured into the otic bulla after artificial rupture of the round window. The animals were sacrificed immediately, or 1 to 7 days after the operation. The results showed that the blood or the fibrin glue successfully closed the window rupture by closing directly and by facilitating the formation of granulation at the margin of the rupture. Fibrin glue seemed to be preferable to autologous blood due to its non-toxic nature in the inner ear.

Animals↗

PubMed1995

Teebi hypertelorism syndrome: further observations.

A new autosomal dominant syndrome resembling craniofrontonasal syndrome was identified by Teebi [1987: Am J Med Genet 28:581-591]. We report on an additional case of Teebi hypertelorism syndrome. A 6-year-old girl presented with brachycephaly, peculiar facial appearance resembling mild frontonasal "dysplasia", small hands and feet with interdigital webbing. In addition, she had previously undescribed manifestations including ventricular septal defect, lipoma of the occipital area, and hypoplastic left hemisphere of the cerebellum. These seem to expand the phenotype of Teebi hypertelorism syndrome. The proposita's father had mild manifestations of the condition including flat occiput, widow's peak, small ears, bulbous nose, brachydactyly with interdigital webbing, and mild shawl scrotum.

Abnormalities, Multiple↗

PubMed1995

Structure and chromosomal localization of the human stromal cell-derived factor 1 (SDF1) gene.

Stromal cell-derived factors 1 alpha and 1 beta are small cytokines belonging to the intercrine CXC subfamily and originally isolated from a murine bone-marrow stroma cell line by the signal sequence trap method. cDNA and genomic clones of human SDF1 alpha and SDF1 beta (SDF1A and SDF1B) were isolated and characterized. cDNAs of SDF1 alpha and SDF1 beta encode proteins of 89 and 93 amino acids, respectively. SDF1 alpha and SDF1 beta sequences are more than 92% identical to those of the human counterparts. The genomic structure of the SDF1 gene revealed that human SDF1 alpha and SDF1 beta are encoded by a single gene and arise by alternative splicing. SDF1 alpha and SDF1 beta are encoded by 3 and 4 exons, respectively. Ubiquitous expression of the SDF1 gene, except in blood cells, was consistent with the presence of the GC-rich sequence in the 5'-flanking region of the SDF1 gene, as is often the case in the "housekeeping" genes. Although genes encoding other members of the intercrine family are localized on chromosome 4q or 17q, the human SDF1 gene was mapped to chromosome 10q by fluorescence in situ hybridization. Strong evolutionary conservation and unique chromosomal localization of the SDF1 gene suggest that SDF1 alpha and SDF1 beta may have important functions distinct from those of other members of the intercrine family.

Amino Acid Sequence↗