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Biomedical subjects

M Takagi

Publications and source records attributed to M Takagi.

At least 19 recordsLinked to original sources
PubMed1992

Stimulation of mouse connective tissue-type mast cells by hemopoietic stem cell factor, a ligand for the c-kit receptor.

The proliferative capacity of mouse connective tissue-type mast cells (CTMC) was analyzed by using a newly discovered c-kit ligand, termed stem cell factor (SCF). More than 90% of CTMC in the peritoneal cavity responded to recombinant rat SCF (rrSCF) and were able to give rise to pure mast cell colonies in methylcellulose culture. Serial observation (mapping) of growth of individual CTMC in culture containing rrSCF confirmed their striking proliferative ability. No serum but accessory cells (non-CTMC cells) in the peritoneal population were required for the clonal growth of CTMC induced by rrSCF in our methylcellulose culture of whole peritoneal cells. The rrSCF-induced mast cell colony formation from peritoneal CTMC was completely inhibited by the addition of anti-c-kit antibody, which can block the binding of SCF to c-kit, to the culture. When IL-3 was combined with rrSCF, mast cell colonies dramatically increased in size. Mapping studies revealed that the combination of the two factors augmented the proliferative rate of CTMC. Approximately 60% of the constituent cells of the mast cell colonies which were formed from peritoneal CTMC in the culture containing rrSCF alone were stained with berberine sulfate, which is a characteristic of CTMC. However, most mast cells which were induced by rrSCF+IL-3 from peritoneal CTMC contained berberine(-)-safranin(-)-Alcian blue(+) granules. Although IL-4 exhibited little synergism with rrSCF in the induction of CTMC proliferation, the addition of IL-4 to the culture containing rrSCF+IL-3 resulted in an increase in mast cells which retained CTMC characteristics.

Animals↗
PubMed1992

Primary sequence analysis of Clostridium cellulovorans cellulose binding protein A.

The cbpA gene for the Clostridium cellulovorans cellulose binding protein (CbpA), which is part of the multisubunit cellulase complex, has been cloned and sequenced. When cbpA was expressed in Escherichia coli, proteins capable of binding to crystalline cellulose and of interacting with anti-CbpA were observed. The cbpA gene consists of 5544 base pairs and encodes a protein containing 1848 amino acids with a molecular mass of 189,036 Da. The open reading frame is preceded by a Gram-positive-type ribosome binding site. A signal peptide sequence of 28 amino acids is present at its N terminus. The encoded protein is highly hydrophobic with extremely high levels of threonine and valine residues. There are two types of putative cellulose binding domains of approximately 100 amino acids that are slightly hydrophilic and eight conserved, highly hydrophobic beta-sheet regions of approximately 140 amino acids. These latter hydrophobic regions may be the CbpA domains that interact with the different enzymatic subunits of the cellulase complex.

Amino Acid Sequence↗
PubMed1992

Causes of oral tongue cancer treatment failures. Analysis of autopsy cases.

Eighty-three autopsy cases of squamous cell carcinoma of the oral tongue were reviewed to identify retrospectively the causes of treatment failure. The cure rate for the primary cancers at autopsy was 48.2% (40 of 83). Regional lymph node metastases were found in 71.1% (59 of 83). Regional metastases and/or juxtaprimary recurrence frequently spread continuously and diffusely, forming bulky neck tumors in 38.6% (32 of 83). The incidence of distant lymph node metastasis (below the clavicle) and hematogenous metastasis was 35.4% (29 of 82) and 58.5% (48 of 82), respectively. The lung was the most common site of hematogenous metastases (52.4%, 43 of 82). Hematogenous metastasis occurred more frequently in the younger age group (less than 40 years of age; P = 0.03). Distant lymph node metastases were identified in the lung hilar, bifurcation, and paratracheal nodes in 89.7% (26 of 29) and had a statistically significant association with lung hematogenous metastasis. Univariate analysis revealed that gross appearance, tumor stage, clinical stage, presence of cervical lymph node metastasis, and interval from N0 to NX were significant predictors of survival time (duration from initial treatment to death). Rupture of the neck vessels was fatal in eight patients (9.6%), and hypercalcemia was seen in six (7.2%). Pulmonary infection was the direct cause of death in 33.7% of patients (28 of 83). Secondary malignant lesions occurred in 22.9% (19 of 83).

Adult↗
PubMed1992

Interferon-gamma inhibits proliferation, but not commitment, of murine granulocyte-macrophage progenitors.

We investigated the effects of interferon gamma (IFN-gamma) on the growth of murine hematopoietic progenitors. IFN-gamma inhibited granulocyte colony-stimulating factor (G-CSF)- and interleukin-3 (IL-3)-dependent colony growth by granulocyte-macrophage (GM) progenitors derived from the bone marrow cells of normal mice. However, the number of IL-3-dependent GM colonies formed by the bone marrow cells of 5-fluorouracil (5-FU)-treated mice was not influenced by the addition of IFN-gamma. Replating experiments suggested that IFN-gamma suppressed GM colony growth directly and that it exerted an inhibitory effect on the proliferation, but not on the commitment, of GM progenitors. In contrast, IFN-gamma failed to suppress colony growth by mast cell progenitors. Erythroid and megakaryocytic progenitors exhibited different responses to IFN-gamma depending on mouse strains. These results suggest that potent negative regulators are not always inhibitors of hematopoietic progenitors.

Animals↗
PubMed1992

Reconsideration of Bell's phenomenon using a magnetic search coil method.

The exact direction, amplitude and time course of Bell's phenomenon is still controversial. We evaluated the eye movements associated with spontaneous blinks, voluntary blinks and prolonged eyelid closure using a magnetic search coil method. Spontaneous blinks were accompanied by transient downward and nasalward eye movements, and similar movement accompanying voluntary blinks were often followed by upward movements. The eye positions occurring immediately after blinks often differed from the initial positions and were followed by corrective saccades, which disappeared when the subjects did not fixate. Prolonged eyelid closure was accompanied by tonic eye elevation and voluntary blinks were accompanied by marked transient eye elevation when eyelid closure was mechanically impeded. Under normal conditions Bell's phenomenon does not occur during blinks.

Adult↗
PubMed1992

Partial portal arterialization for the prevention of massive liver necrosis following extended pancreatobiliary surgery: experience of two cases.

Massive liver necrosis, which is a severe and highly fatal complication after extended pancreatobiliary surgery, may occur due to an interruption of the hepatic arterial flow caused by such events as an excision of the hepatic artery invaded by cancer, a ligation of the postoperatively ruptured hepatic artery, or a thrombotic obstruction of the reconstructed hepatic artery. In order to improve this ischemic state of the liver, we have performed a partial arterialization of the portal vein by making an arteriovenous shunt at the mesenteric vascular branches in two cases. Although a sufficient pathophysiological investigation could not be fully conducted, partial portal arterialization was considered to be effective in one patient, while no clinically noticeable adverse effects were revealed in the other patient.

Arteriovenous Shunt, Surgical↗
PubMed1992

Biochemical and immuno- and lectin-histochemical studies of solubility and retention of bone matrix proteins during EDTA demineralization.

The present study utilized biochemical and immuno- and lectin-histochemical methods to demonstrate solubility and retention of mineral-binding non-collagenous proteins in rat midshaft subperiosteal bone during EDTA demineralization. A monoclonal antibody (9-A-2) specific for chondroitin 4-sulphate and dermatan sulphate and wheat germ agglutinin (WGA) specific for N-acetyl-D-glucosamine, N-acetylneuraminic acid, and N-acetyl-D-galactosamine were used. Bone proteins were extracted from fresh unfixed or aldehyde-fixed specimens with a three step extraction procedure, 4 M guanidine HCl (GdnCl), aqueous EDTA without GdnCl, followed by GdnCl. For comparison with the second extraction step, ethanolic trimethylammonium EDTA (ethanolic EDTA) was substituted for aqueous EDTA. Based on protein staining and Western blot analysis of SDS-polyacrylamide gel electrophoresis of each extract using 9-A-2 and WGA, retention of mineral-binding proteins extractable from fresh specimens with aqueous EDTA was greatly increased in tissue when ethanolic EDTA was used. Their retention was even greater with prior aldehyde fixation. Maximum retention with no detectable solubility of 9-A-2 and WGA reactive proteins was obtained after ethanolic EDTA extraction of aldehyde-fixed specimens, which concomitantly provided the strongest immuno- and lectin staining. These results indicate that this combined method dramatically improves retention of PGs and glycoproteins during demineralization of bone tissues and provides the best method for localizing these glycoconjugates.

Acetylgalactosamine↗
PubMed1992

Immunoelectron microscopic studies of glycosaminoglycans in the metaphyseal bone trabeculae of growing rats.

The types and distribution of glycosaminoglycans (GAGs) were studied immunocytochemically in osteoid, mineralized bone matrix, and cartilage matrix of growing rat metaphyseal bone after aldehyde fixation and EDTA demineralization, using four monoclonal antibodies (mAbs 1-B-5, 2-B-6, 3-B-3 and 5-D-4). These mAbs specifically recognize epitopes in non-sulphated chondroitin (C0-S); chondroitin 4-sulphate (C4-S) and dermatan sulphate (DS); chondroitin 6-sulphate (C6-S) and C0-S; and keratan sulphate (KS) respectively. In osteoid, all mAbs except 1-B-5 weakly stained matrix material on and between collagen fibrils, and moderately stained organic material corresponding to bone nodules, which are known sites of mineralization. However, the staining of osteoid abruptly decreased at the mineralization front; weak staining was confined mostly to the organic material of bone nodules in mineralized bone matrix, with very weak or no staining of the rest of the bone matrix. This staining progressively decreased toward the mineralized cartilage matrix and became negative. The mineralized cartilage matrix and lamina limitans reacted strongly with all mAbs except 5-D-4. These results indicate that osteoid contains sulphated proteoglycans containing C4-S and/or DS, C6-S and KS, and subsequent bone matrix mineralization appears to require accumulation of these macromolecules within bone nodules and eventual loss of these substances for complete mineralization, whereas proteoglycans containing C0-S, C4-S and/or DS, and C6-S still exist in mineralized cartilage matrix and lamina limitans.

Animals↗
PubMed1992

Evaluation of epidermal growth factor receptor in squamous cell carcinoma of the oral cavity.

Forty-seven cases of oral squamous cell carcinoma were examined immunohistochemically by the avidin-biotin peroxidase complex method with anti-epidermal growth factor (EGF) receptor mouse monoclonal antibody, and 24 cases (51%) were shown to have EGF receptor-positive cells. Correlation was strong between presence of EGF receptors and differentiation; the EGF receptor-positive cells were differentiated, whereas poorly differentiated tumors exhibited less intense staining. EGF receptor gene and c-erb B-1 by Southern blot analysis disclosed that one of 25 cases of squamous cell carcinoma exhibited a fourfold amplification of the gene.

Blotting, Southern↗
PubMed1992

Influence of substituting B2O3 for CaF2 on the bonding behaviour to bone of glass-ceramics containing apatite and wollastonite.

Glass-ceramics containing crystalline oxy-fluoroapatite (Ca10(PO4)6(O,F2)) and wollastonite (CaSiO3) (designated AWGC) are reported to have a fairly high mechanical strength as well as the capability of forming a chemical bond with bone tissue. The chemical composition is MgO 4.6, CaO 44.9, SiO2 34.2, P2O5 16.3, and CaF2 0.5 in weight ratio. In this study the influence of substituting B2O3 for CaF2 on the bonding behaviour of glass-ceramics containing apatite and wollastonite to bone tissue was investigated. Two kinds of glass-ceramics containing apatite and wollastonite were prepared. CaF2 0.5 was replaced with B2O3 at 0.5 and 2.0 in weight ratio (designated AWGC-0.5B and AWGC-2.0B). Rectangular ceramic plates (15 x 10 x 2 mm, abraded with No. 2000 alumina powder) were implanted into a rabbit tibia. The failure load, when an implant detached from the bone, or the bone itself broke, was measured. The failure load of AWGC-0.5B was 8.00 +/- 1.82 kg at 10 weeks after implantation and 8.16 +/- 1.36 kg at 25 weeks after implantation. The failure load of AWGC-2B was 8.08 +/- 1.70 kg at 10 weeks after implantation and 9.92 +/- 2.46 kg at 25 weeks after implantation. None of the loads for the two kinds of glass-ceramics decreased as time passed. Giemsa surface staining and contact microradiography revealed direct bonding between glass-ceramics and bone. SEM-EPMA showed a calcium-phosphorus rich layer (reaction zone) at the interface of ceramics and bone tissue. The thickness of the reaction zone was 10 to -15 microns and did not increase as time passed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Functional roles of the lateral suprasylvian cortex in ocular near response in the cat.

The lateral suprasylvian (LS) area, an extrastriate visual area in the cat, has been suggested to play an important role in processing motion in 3-dimensional visual space. In addition, the LS area is related to all three components of the ocular near response, i.e. lens accommodation, pupillary constriction, and ocular convergence: microstimulation in this area evoked these intra- and extraocular movements, and neuronal discharges associated with these movements were also found. Anatomical pathways, direct and indirect, from this area to premotor nuclei in the brainstem are known to exist. The present paper reviews studies useful for assessing the functional roles played by the LS area in triggering and modulating component movements in the ocular near response.

Accommodation, Ocular↗
PubMed1992

Ocular convergence-related neuronal responses in the lateral suprasylvian area of alert cats.

Neuronal spike discharges were recorded from the lateral suprasylvian (LS) area while ocular convergence was elicited in five alert cats. Ocular convergence was elicited by presenting a visual target moving in depth. Cats were rewarded for convergence eye movement. In 9 out of 426 cells sampled in the caudal postero-medial LS area, the number of spikes was positively correlated with the peak eye velocities during ocular convergence. Significant correlation was found mostly within 400 ms preceding the moment at which the maximum velocity of ocular convergence was obtained. The result favors the hypothesis that the LS area plays an important role in the integrative control of ocular convergence.

Animals↗
PubMed1992

Detection of feline immunodeficiency proviral DNA in peripheral blood lymphocytes by the polymerase chain reaction.

Feline immunodeficiency virus (FIV) proviral DNA was detected by the polymerase chain reaction method (PCR). PCR products were detected by gel electrophoresis and ethidium bromide staining. The P-10, P-15 and P-24 regions of the gag gene of FIV were chosen as the target sequences for amplification, and three primer pairs were prepared. The PCR products subjected to amplification with each primer pair were found to possess sites of digestion by a restriction enzyme, as hypothesized. They did not react with feline leukemia virus (FeLV)-infected or feline syncytium-forming virus (FeSFV)-infected cell-derived DNA, and specifically amplified FIV-infected cell-derived DNA. FIV proviral DNA was detected by the PCR method with either primer pair (one-step amplification: single PCR) in DNA derived from peripheral blood lymphocytes (PBL) from 7 of 12 FIV antibody-positive cats. When PCR products in each of the 12 cats were subjected to a second amplification using the same primer pair (two-step amplification: double PCR), FIV proviral DNA was detected in all of the cats. When PBL samples collected from three cats that were negative and three that were positive in the single PCR were cultured for a few weeks in the presence of interleukin 2, FIV proviral DNA was detected in all six cats by the single PCR method. The results suggest that either the use of cultured PBL as the sample or the performance of the double PCR method enables simple and specific detection of FIV proviral DNA in PBL.

Animals↗
PubMed1992

Evidence that three histidine residues of a base non-specific and adenylic acid preferential ribonuclease from Rhizopus niveus are involved in the catalytic function.

In order to study the structure-function relationship of an RNase T2 family enzyme, RNase Rh, from Rhizopus niveus, we investigated the roles of three histidine residues by means of site-specific mutagenesis. One of the three histidine residues of RNase RNAP Rh produced in Saccharomyces cerevisiae by recombinant DNA technology was substituted to a phenylalanine or alanine residue. A Phe or Ala mutant enzyme at His46 or His109 showed less than 0.03%, but a mutant enzyme at His104 showed 0.54% of the enzymatic activity of the wild-type enzyme with RNA as a substrate. Similar results were obtained, when ApU was used as a substrate. The binding constant of a Phe mutant enzyme at His46 or His109 towards 2'-AMP decreased twofold, but that at His104 decreased more markedly. Therefore, we assumed that these three histidine residues are components of the active site of RNase Rh, that His104 contributes to some extent to the binding and less to the catalysis, and that the other two histidine residues and one carboxyl group not yet identified are probably involved in the catalysis. We assigned the C-2 proton resonances of His46, His104, and His109 by comparison of the 1H-NMR spectra of the three mutant enzymes containing Phe in place of His with that of the native enzyme, and also determined the individual pKa values for His46 and His104 to be 6.70 and 5.94. His109 was not titrated in a regular way, but the apparent pKa value was estimated to be around 6.3. The fact that addition of 2'-AMP caused a greater effect on the chemical shift of His104 in the 1NMR spectra as compared with those of the other histidine residues, may support the idea described above on the role of His104.

Adenosine↗
PubMed1992

Tibio-talo-calcaneal fusion with a free vascularized fibular graft in comminuted open fractures of the talus and the calcaneus.

An operation is described in which a free vascularized fibular graft with a peroneal cutaneous flap is used for tibio-talo-calcaneal fusion and simultaneous skin coverage in treatment of comminuted open fractures of the talus and the calcaneus involving large skin loss. Nine months postoperatively, the tibio-talo-calcaneal arthrodesis was successful, with good coverage of the skin defect on the medial aspect of the sole. One year 7 months postoperatively, the patient is free of pain and able to walk with full weightbearing on the foot.

Arthrodesis↗