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Biomedical subjects

H Takeshima

Publications and source records attributed to H Takeshima.

At least 181 records · Page 10Linked to original sources
PubMed1990

Regulatory regions of the mitochondrial and cytosolic isoenzyme genes participating in the malate-aspartate shuttle.

The malate-aspartate shuttle, consisting of mitochondrial and cytosolic aspartate aminotransferase and mitochondrial and cytosolic malate dehydrogenase, is a major pathway for the transport of reducing equivalents from cytosol to mitochondria in mammals. To elucidate molecular mechanisms regulating metabolic coordination between the mitochondria and the cytosol, we analyzed the 5'-flanking regulatory regions of the complete set of mouse isoenzyme genes playing a pivotal role in the shuttle. Deletion analysis and an in vivo transfection assay, using NIH3T3 cells, revealed that all the promoter regions are located within the 300-base pair regions upstream from the initiation codon. Subsequently, DNase I footprinting analyses using NIH3T3 cell nuclear extracts led to identification of several protein binding sites within these promoter regions. A synthetic oligomer containing the consensus binding site sequence for CTF/NFI, a transcription factor for RNA polymerase II, competed for the binding of proteins to the promoter regions of cytosolic aspartate aminotransferase and mitochondrial and cytosolic malate dehydrogenase genes, but not for that of the mitochondrial aspartate amino-transferase gene. On the other hand, a synthetic oligomer containing the consensus binding site sequence for Sp1, which activates transcription from promoters containing properly positioned GC boxes, competed for protein(s) binding to the promoter region of the mitochondrial aspartate aminotransferase gene.

Animals↗
PubMed1990

Transforming growth factor-beta modulates proliferation and differentiation of mouse clonal osteoblastic MC3T3-E1 cells depending on their maturation stages.

The effect of transforming growth factor-beta (TGF-beta) on proliferation and differentiation of mouse clonal osteoblastic cells (MC3T3-E1) was examined in vitro in three different stages of their differentiation. Stage I (1-3 days after plating) was characterized by rapid cell growth, negligible alkaline phosphatase (ALP) activity and high proteoglycan synthesis, but low collagen production. In stage II (3-5 days after plating), proteoglycan synthesis sharply decreased and ALP activity and collagen synthesis began to increase. Stage III (7-9 days after plating) was characterized by maximal osteoblastic phenotypes. Treating MC3T3-E1 cells with 1 ng/ml of TGF-beta greatly inhibited DNA synthesis in stage I but not in stage II. In contrast, TGF-beta dose-dependently stimulated the synthesis of collagenase digestible proteins (CDP), noncollagenous proteins (NCP) and proteoglycan, especially in stage II. The minimum effective dose of TGF-beta in this stage was as low as 0.04-0.2 ng/ml. In stages I and III, the MC3T3-E1 cells were rather insensitive to TGF-beta in increasing three osteoblastic phenotypes. The increase in ALP activity in stages II and III was inhibited by 1 ng/ml of TGF-beta. These results indicate that the response to TGF-beta of mouse clonal osteoblastic MC3T3-E1 cells changes depending on their maturation stages.

Alkaline Phosphatase↗
PubMed1990

[Reconstruction of occlusal function with osseointegrated implant following mandibular resection].

We succeeded satisfactorily to restore the occlusal function by use of an osseointegrated implant following iliac bone grafting and partial mandibulectomy in 4 patients who underwent surgical resection of odontgenic cyst and benign or malignant tumor of the oral cavity. Case 1: The patient was a 19-year-old man. Partial resection of the mandible was carried out under the diagnosis of odontgenic keratocyst of the left lateral incisor to the 1st premolar region. Iliac bone grafting was performed as secondary surgery. After confirmation of the fusion of the grafted bone, the occlusal function was restored by use of an osseointegrated implant. Case 2: The patient was a 36-year-old man. After segmental resection of the mandible under the diagnosis of ameloblastoma of the left 2nd premolar to the right 2nd premolar region, mandibular reconstruction was carried out with an A-O plate. Iliac bone grafting was performed as secondary surgery. After fusion of the grafted bone had been confirmed, the A-O plate was remounted and the fixture was immediately implanted. Five months later, vestibuloplasty by free skin grafting and attachment of the abutment were carried out. A superstructure was mounted. Case 3: The patient was a 22-year-old woman. The histopathologically confirmed odontogenic myxoma in the right mandible posteriorly from the second premolar was resected. Immediate reconstruction of the mandible was carried out by use of an iliac bone graft. After confirmation of the fusion of the grafted bone, the occlusal function was restored by use of an osseointegrated implant. Case 4: The patient was a 57-year-old woman with carcinoma of the right lingual margin and mouth floor. The tumor was resected with the mandibular margin. Immediate reconstruction of the tongue and mouth floor with a major pectoral muscle skin flap was carried out. In the absence of evidence of recurrence, restoration of the occlusal function was attempted with an osseointegrated implant.

Adult↗
PubMed1989

Functional expression of the calcium release channel from skeletal muscle ryanodine receptor cDNA.

Combined patch-clamp and fura-2 measurements were performed to study the calcium release properties of Chinese hamster ovary (CHO) cells transfected with the rabbit skeletal muscle ryanodine receptor cDNA carried by an expression vector. Both caffeine (1-50 mM) and ryanodine (100 microM) induced release of calcium from intracellular stores of transformed CHO cells but not from control (non-transfected) CHO cells. The calcium responses to caffeine and ryanodine closely resembled those commonly observed in skeletal muscle. Repetitive applications of caffeine produced characteristic all-or-none rises in intracellular calcium. Inositol 1,4,5-trisphosphate (IP3) neither activated the ryanodine receptor channel nor interfered with the caffeine-elicited calcium release. These results indicate that functional calcium release channels are formed by expression of the ryanodine receptor cDNA.

Animals↗
PubMed1989

Primary structure and functional expression of the cardiac dihydropyridine-sensitive calcium channel.

In cardiac muscle, where Ca2+ influx across the sarcolemma is essential for contraction, the dihydropyridine (DHP)-sensitive L-type calcium channel represents the major entry pathway of extracellular Ca2+. We have previously elucidated the primary structure of the rabbit skeletal muscle DHP receptor by cloning and sequencing the complementary DNA. An expression plasmid carrying this cDNA, microinjected into cultured skeletal muscle cells from mice with muscular dysgenesis, has been shown to restore both excitation-contraction coupling and slow calcium current missing from these cells, so that a dual role for the DHP receptor in skeletal muscle transverse tubules is suggested. We report here the complete amino-acid sequence of the rabbit cardiac DHP receptor, deduced from the cDNA sequence. We also show that messenger RNA derived from the cardiac DHP receptor cDNA is sufficient to direct the formation of a functional DHP-sensitive calcium channel in Xenopus oocytes. Furthermore, higher calcium-channel activity is observed when mRNA specific for the polypeptide of relative molecular mass approximately 140,000 (alpha 2-subunit) associated with skeletal muscle DHP receptor is co-injected.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1989

Primary structure and expression from complementary DNA of skeletal muscle ryanodine receptor.

The sequence of 5,037 amino acids composing the ryanodine receptor from rabbit skeletal muscle sarcoplasmic reticulum has been deduced by cloning and sequencing the complementary DNA. The predicted structure suggests that the calcium release channel activity resides in the C-terminal region of the receptor molecule, whereas the remaining portion constitutes the 'foot' structure spanning the junctional gap between the sarcoplasmic reticulum and the transverse tubule.

Amino Acid Sequence↗
PubMed1989

Stable expression of hepatitis B virus genome in a primate kidney cell.

Transfection of Vero cells with cloned hepatitis B virus (HBV) DNA resulted in the secretion of hepatitis B surface protein (HBsAg) and core proteins (HBc/eAg). Syntheses of both viral antigens in the transformed Vero cells continued for at least 50 days after cultivation. HBsAg particles were composed of many spherical and some filamentous particles containing both pre-S1 and pre-S2 domains. Restriction analysis of the transfected cellular DNA showed that one copy of HBV DNA was integrated in the cells. Some species of HBV-specific RNA were detected by Northern blot, and among these a major transcript was found to migrate at 2.1 kb by S1-mapping analysis. Viral core proteins present in the culture medium were fractionated and characterized by cesium chloride gradient and found to form particles.

Animals↗
PubMed1989

A deacylation enzyme for aculeacin A, a neutral lipopeptide antibiotic, from Actinoplanes utahensis: purification and characterization.

An enzyme, tentatively termed aculeacin A acylase, useful in preparing deacylated peptides which are used as starting material for semisynthetic antifungal antibiotics, was purified from the culture filtrate of Actinoplanes utahensis NRRL12052. The purification involved ultrafiltration and column chromatographies on DEAE-cellulose, hydroxyapatite, and Butyl-Toyopearl 650M. The purified enzyme was composed of two dissimilar subunits with molecular weights of 55,000 and 19,000. The subunits were dissociated in the presence of 0.1% SDS or 6 M guanidine hydrochloride; the dissociation accompanied loss of acylase activity. The enzyme was fully active at pH 7.0 and at 60 degrees C. Its pI was estimated to be above 10.25. The Km and Vmax for aculeacin A were 1.53 mM and 39.7 mumol/min/mg-protein, respectively.

Actinomycetales↗
PubMed1989

[Studies on the urophonography (1)--Basic investigation with the model of lower urinary tract].

The purpose of this study is to ascertain whether the urinary (turbulent) flow really causes the sounds during micturition in humans. For this purpose the artificial bladder and urethra, which were made of silicon rubber (3M Co. Minnesota, U.S.A.), were used. The manometric device was attached to the bladder to measure the intravesical pressure. Outside the bladder neck a prostate like protrusion surrounding the urethra was made. A microphone was attached to this protrusion to detect the sound. A recording system was also adopted. The bladder was filled with 200 ml of sterile eater. By pressurising the artificial bladder at 100 cmH2O, the water passed through the urethra. During this artificial voiding the sound detection was undertaken. At the same time uroflowmetry was also performed. It was demonstrated that sound spikes were recorded whenever water in the artificial bladder passed through the artificial urethra.

Auscultation↗
PubMed1989

[Studies on the urophonography (2)--Clinical investigation on normal human subjects and patients with benign prostatic hypertrophy].

Recently we have developed an entirely new method of sonic detection of lower urinary tract disorders during micturition. The detection of these sounds was performed by a data catching and recording system, consisting of a detector, amplifier, and recorder. This procedure was designated as "urophonography" and its recording as "urophonogram". Twenty-five patients with BPH before and three months after suprapubic prostatectomy and 10 healthy male volunteers underwent urophonography. The urophonograms were classified into four types. Type 1 was characterized by its diamond shape, while Type 2 was characterized by its random sound spikes. Type 3 was a mixture of Types 1 and 2. Type 4 had only few sound spikes. Analysis of these urophonograms also revealed that the frequencies of these urethral sounds belonged to the range from 0.4 to 1.5 KHz. The amplitude (power) of the sounds was in the range of 40-60 dB. Healthy volunteers belonged to Type 4. BPH patients belonged to Types 1, 2 and 3 at equal frequency. Comparison of uroflowmetric parameters with urophonograms revealed that Type 3 patients with BPH showed a lesser degree of micturition disturbances, which was consistent with the weight of prostatic tumors surgically resected. Urophonography was undertaken before and after the treatment on these patients. It was clearly shown that the pattern of urophonograms shifted to normal (Type 4). It was considered that urophonograms were useful for urodynamic investigation.

Aged↗
PubMed1989

[Studies on the urophonography (3)--Clinical investigation on prostatic cancer].

Recently we have developed an entirely new method of sonic detection of lower urinary tract disorders during micturition. This procedure was designated as "urophonography" and its recording as "urophonogram". Sixteen patients with prostatic cancer before and three months after anti-androgenic therapy and ten healthy male volunteers underwent urophonography. The urophonograms were classified into four types. Type 1 was characterized by its diamond shape, while Type 2 was characterized by its random sound spikes. Type 3 was a mixture of Types 1 and 2. Type 4 had few sound spikes. Analysis of these urophonograms also revealed that the frequencies of these urethral sounds belonged to the range from 0.4 to 1.5 KHz. The amplitude (power) of the sounds was in the range of 40-60 dB. Healthy volunteers belonged to Type 4. Prostatic cancer patients belonged to Types 1, 2 and 3 at 18.8, 68.8, nad 12.4%, respectively. After the treatment the percentages of Types 1, 2, 3, and 4 changed to 18.8, 50.0, 0, and 31.2%, respectively. Comparison of uroflowmetric parameters with urophonograms showed that Type 2 patients showed a lesser degree of micturition disturbances, evidenced by these parameters. It was considered that urophonograms were useful as urodynamic investigation.

Aged↗
PubMed1989

[Mechanical study on the stability of multiform mini-plates. I. Double-T-type plate (90, regular, 6-holes) in mandibular body fracture].

In this present paper, we reported the stability of osteosynthesis using a special type of mini-plate for mandibular fractures as evaluated from a mechanical study with static loading. The materials used in this study were fifteen bars made of acrylic resin, each divided at the center of its length into two parts to simulate a condition of mandibular body fracture. Following the fixation of these materials with mini-plates firmly attached between their cut ends, the bars were secured in a vice at one end and a static load was applied from the vertical direction at the other end. The amount of displacement of the loaded end was investigated with a displacement-measuring device, and the strains on mini-plates and test bars were measured with strain gauges. A comparative study was conducted on three kinds of mini-plates: 1) Group S, fixed with one Champy mini-plate, 2) Group W, fixed with two Champy mini plates, 3) Group T, fixed with one double-T-type mini-plate. The following results were obtained: 1) The amount of displacement was largest in the vertical direction and smallest in the horizontal direction in the three groups. Especially in group T, it was smaller the longitudinal and horizontal axes than in the other two groups. 2) Longitudinal strain of the plate was smallest in group W. However, the strain on the test bar was smallest group S. Especially , in group T, the largest compressive strain was observed at the lower portion of the synthesized ends.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Plates↗
PubMed1988

Structural organization of the mouse mitochondrial malate dehydrogenase gene.

Structural organization of the mouse mitochondrial malate dehydrogenase (EC 1.1.1.37) gene was determined by analyzing a genomic DNA fragment isolated from a cosmid library. The gene is 12,000 base-pairs long and contains nine exons interrupted by eight introns of various sizes. The 5' and 3'-flanking regions, and the exact sizes and boundaries of the exon blocks including the transcription-initiation sites were determined. In the 5'-flanking region, there is neither a TATA box nor a CAAT box. Instead of these sequences, there are six copies of the GGGCGG or CCGCCC sequence, which is a potential binding site for the transcription factor, Sp1. The 5'-flanking region up to about 600 nucleotides is G + C-rich (65%) and contains sequences compatible with the formation of a number of potentially stable stem-loop structures. S1 nuclease mapping and primer extension analysis demonstrated that transcription of the mitochondrial malate dehydrogenase gene initiates at multiple sites. Comparison of the nucleotide sequence of the promoter region of the mitochondrial malate dehydrogenase gene with that of the mitochondrial aspartate aminotransferase gene, revealed that there are several highly conserved regions between these two mitochondrial enzyme genes participating in the malate-aspartate shuttle.

Amino Acid Sequence↗