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Biomedical subjects

M Takekawa

Publications and source records attributed to M Takekawa.

34 records · Page 2Linked to original sources
PubMed1996

Morphological changes of autoclaved autogenic bone implantation and autoclaved autogenic bone supplemented with allogenic demineralized bone matrix in rat parietal bone.

The healing process of resected, autoclaved (121 degrees C, 20 minutes) and re-implanted bone in the rat parietal bone was compared with that of autoclaved bone that was supplemented with allogenic bone matrix (AAA-bone), using a scanning electron microscope and a light microscope. In the implant without AAA-bone, bone union and replacement of the autoclaved bone was seen at 2 weeks after implantation. There was no evidence of any inflammatory reaction around the autoclaved bone. The implant was gradually replaced by the new bone. In the implant with AAA-bone, the new bone formation around the implanted bone was more abundant than that of the implant without AAA-bone. An inflammatory reaction was also observed after 1 week. The replacement of the implant with AAA-bone was inferior to the nonsupplemented group. The reason for the poor replacement was the disturbance of the blood supply in the implant by abundant new bone formation. In these results, the autoclaved bone re-implantation was an excellent bone substitute with osteoconductive ability and biocompatibility. The implantation with AAA-bone was good for the new bone formation, but the position and the technique of supplement with AAA-bone have to be more deeply investigated.

Animals↗
PubMed1995

Activation of yeast PBS2 MAPKK by MAPKKKs or by binding of an SH3-containing osmosensor.

The role of mitogen-activated protein (MAP) kinase cascades in integrating distinct upstream signals was studied in yeast. Mutants that were not able to activate PBS2 MAP kinase kinase (MAPKK; Pbs2p) at high osmolarity were characterized. Pbs2p was activated by two independent signals that emanated from distinct cell-surface osmosensors. Pbs2p was activated by MAP kinase kinase kinases (MAPKKKs) Ssk2p and Ssk22p that are under the control of the SLN1-SSK1 two-component osmosensor. Alternatively, Pbs2p was activated by a mechanism that involves the binding of its amino terminal proline-rich motif to the Src homology 3 (SH3) domain of a putative transmembrane osmosensor Sho1p.

Amino Acid Sequence↗
PubMed1995

[Frontal acute extradural hematoma due to contrecoup injury: a case report].

Acute extradural hematoma, a collection of blood between the inner table of the skull and the dura, generally occurs in coup craniocerebral trauma with skull fracture. We report here a case of a 52-year-old female who had had a traffic accident. She suffered a serious wound consisting of a subcutaneous hematoma with skull fracture and so called Battle's sign on the left occipital region but not wounded in any other region. CT scan obtained shortly after the injury demonstrated a thin acute extradural hematoma with intracranial air under the subcutaneous hematoma in the left occipital region, and another hematoma with subarachnoid hemorrhage due to contrecoup head trauma in the right frontal region. We treated her conservatively with a common drip. She sometimes vomited during the several hours after admission. CT scan six hours later showed that the contrecoup extradural hematoma had enlarged. Immediately, we carried out the evacuation of the hematoma with decompressive craniectomy. Her scalp, cranium and frontal skull base over the extradural hematoma were without injury, and multiple small haemorrhages were found to have occurred on the surface of the dura that had been separated from the inner table of the skull. After the operation, the patient recovered consciousness. Contrecoup acute extradural hematoma is very rare. It seems that the appearance of hematoma in our case resulted from the frontal dural separation due to distortion of the cranium brought on by the force of the impact and the subsequent gradual growth of the hematoma under the stimulation of several bouts of vomiting.

Acute Disease↗
PubMed1995

Scanning electron and light microscopic observations on the healing process after sintered bone implantation in rats.

The healing process after implantation of sintered bone in the rat parietal bone was compared with that of synthetic hydroxyapatite using both scanning electron and light microscopy. The results showed that the differences between the sintered natural bone and the synthetic hydroxyapatite implantations were in the states of bone union and the bioresorbability of the implanted materials, even though both materials consist of the same hydroxyapatite. In the sintered bone implantation, the newly formed bone invaded into the material at 1 to 2 weeks after implantation. The sintered bone surface on the dura mater side was completely covered by the new bone at 5 weeks. It is noteworthy that bone resorbing areas characterized by Howship's lacunae were observed on the sintered bone surface at 2 weeks and the material was replaced by new bone. Light microscopy, which revealed the invasion and the development of the new bone into the sintered bone, supported the scanning electron microscopic observations. In the synthetic hydroxyapatite, the new bone adhered closely to the material just like the sintered bone implantation. The new bone did not invade into the synthetic hydroxyapatite. There was no evidence of the resorption of the hydroxyapatite. This shows that the natural and the biological structures of the sintered bone offer an advantageous environment to fluid circulation and ingrowth after implantation.

Animals↗
PubMed1994

Chromosomal localization of the protein tyrosine phosphatase G1 gene and characterization of the aberrant transcripts in human colon cancer cells.

We have recently described the isolation of the human PTPG1 gene which encodes a member of intracellular protein tyrosine phosphatases that may be candidates for tumor suppressor genes. In order to investigate the abnormality of the PTPG1 transcript in various human cancer cell lines, we have analyzed the consensus catalytic region of PTPG1 cDNA, using the reverse transcription polymerase chain reaction. In a colorectal carcinoma cell line, DLD-1, we found three aberrant transcripts. Sequencing analysis revealed that one had a missense point mutation and the remainders contained 77 bp and 173 bp deletions, respectively. These alterations might directly affect their phosphatase activities. Our findings provide the first evidence for the aberrant transcripts of the protein tyrosine phosphatase in human cancer cells, and suggest that the aberration of PTPG1 gene might be involved in the tumorigenesis. Moreover, the human PTPG1 gene is localized on chromosome 7q11.23, a region with frequent abnormalities implicated in some human cancers.

Amino Acid Sequence↗
PubMed1994

High expression of CD56 (N-CAM) in a patient with cutaneous CD4-positive lymphoma.

Cutaneous lymphoma is a disease characterized with massive skin infiltration of lymphoid malignant cells. They commonly express some T-cell markers, such as CD2, CD3, CD4, and CD7, and thus termed as CTCL (cutaneous T cell lymphoma). Here, we present a case with CD56/N-CAM-positive cutaneous lymphoma, which appears lymphocytic morphology and expresses CD4, but does not express CD2, CD3, CD8, CD14, CD16, CD57, and CD20. The most malignant cells contained no distinctive azurophilic granules in the cytoplasm. Southern blot analysis revealed that T cell receptor-beta, gamma, and immunoglobulin heavy chain genes in the cells were in germ-line configurations. Electron microscopic examination showed characteristics of lymphoid cells with higher nucleocytoplasmic ratio and lacked structures typical of other cell types (i.e., epithelial cells, neuroendocrine cells, and mesenchymal cells). Thus, the cells are likely to be immature lymphoid cells. Histological analysis revealed the cells infiltrate mainly into the dermis with angiocentric growth pattern. The clinical course was aggressive, with rapid involvement of bone marrow and central nervous system. These striking features of the patient may represent a novel fraction (CD2-, CD4+, and CD56+) of cutaneous lymphoma.

Aged↗
PubMed1992

Cloning and characterization of a human cDNA encoding a novel putative cytoplasmic protein-tyrosine-phosphatase.

We have cloned and characterized a human cDNA encoding a new member of the family of cytosolic type protein-tyrosine-phosphatase (PTP), designated as PTPG1, from an adult colon tissue cDNA library by using the PCR product as probe. We obtained 5 cDNA clones, which cover the predicted open reading frame encoding a 88-kDa protein composed of 780 amino acids, and it had no apparent signal or transmembrane sequences, suggesting that it is a cytosolic protein. The N-terminal region had a PTP catalytic domain that is 30-40% identical to previously reported human PTPs. This revealed that the enzyme composes an additional family of human PTPs. PTPG1 was characterized by a long non-enzymatic domain located at the C-terminus, including PEST sequences which are characteristic for short half-life proteins in eukaryotes. Northern blot analysis of PTPG1 mRNA showed a 4.6-kb transcript that was detected in a wide variety of cell lines to suggest its extensive expression.

Amino Acid Sequence↗
PubMed1992

Protein-tyrosine phosphatase expression in pre-B cell NALM-6.

Protein-tyrosine phosphatase (PTP)-related complementary DNAs from NALM-6 (pre-B cell line) were amplified by reverse transcriptase polymerase chain reaction using primers corresponding to the conserved catalytic domains of PTPs. Thirty-three polymerase chain reaction products, identified as PTP related complementary DNAs, were classified to RPTP-alpha, PTP1B, and 4 novel PTPs, which were designated as BPTP-1-4. Their expressions in NALM-6 and other cell lines were confirmed by Northern blot analysis. BPTP-1 and -2 exhibited extensive homology with the first and the second catalytic domains, respectively, of leukocyte common antigen related molecule (LAR) and human PTP delta. The transcriptional sizes of BPTP-1 and BPTP-2 are the same (7.2 kilobases) as that of LAR. The expression of BPTP-1 was abundant in lymphoid cell lines TALL-1 and NALM-6 but small in colon cell line BM314, which is in sharp contrast to the expression of LAR. These data suggest that the expression levels of BPTP-1 and LAR are altered in a cell specific manner, probably making them cell type associated PTPs.

Amino Acid Sequence↗
PubMed1992

cDNA cloning of new protein tyrosine phosphatases in the human colon.

Oligonucleotide probes corresponding to three invariant amino acid sequence motifs within the protein tyrosine phosphatase (PTPase) catalytic domain were synthesized and employed in the polymerase chain reaction (PCR). PCR products amplified from human colonic tissues were analyzed. Among 41 cDNA clones sequenced, two putative novel PTPases designated as CL-6 and CL-2B were isolated. cDNA cloning of CL-6 was performed, and three overlapped cDNA clones encoding part of the coding region, which was 2.1 kb long, were obtained. Expression of mRNAs of these clones was then investigated by Northern blot analysis or reverse transcriptase-PCR, suggesting that CL-6 mRNA may be expressed in a cell-type-specific manner, whereas the expression of CL-2B mRNA could be ubiquitous.

Base Sequence↗
PubMed1992

Hypereosinophilic syndrome accompanied with necrosis of finger tips.

We report a case of hypereosinophilic syndrome (HES) with marked eosinophilia (59.7%) and mononeuritis multiplex (upper limbs and buttocks). Necrosis of the finger tips was the primary manifestation which simultaneously occurred on both sides. These clinical manifestations were improved dramatically by subsequent steroid therapy. Interestingly, an elevation of serum tumor necrosis factor (TNF) was observed. These findings suggest that TNF may play a role in the etiology of necrosis of the finger tips.

Adult↗
PubMed1991

[Consistency in viabilities of mycobacteria detected by FDA/EB staining and colony forming units on the medium].

We have previously reported that the staining of mycobacteria with fluorescein diacetate (FDA) and ethidium bromide (EB) detects viable bacteria and distinguish them from heat-killed bacteria. Whether this method can be applied to clinical specimens has been an important question. In the present experiment, we treated mycobacteria with either UV-irradiation, 70% ethanol, 0.2% benzalconium chloride, 5% saponated cresol solution, or 5% phenol for 24 hours, and stained with FDA/EB to evaluate the effect of sterilization. We also stained samples of sputum from a tuberculosis patient with FDA/EB after treatment with 4% NaOH for 30 min. and neutralized with 1N H2SO4. All the samples were determined for the colony forming units on 1% Ogawa egg media. A good correlation was observed between the results of FDA/EB staining and colony formation. We believe that FDA/EB staining is useful method to detect viable mycobacteria in clinical samples.

Cell Survival↗