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Biomedical subjects

Y Takebe

Publications and source records attributed to Y Takebe.

At least 109 records · Page 6Linked to original sources
PubMed1984

STA-MCA anastomosis in patients with skull base tumours involving the internal carotid artery--haemodynamic assessment by ultrasonic Doppler flowmeter.

The role of superficial temporal artery--middle cerebral artery (STA-MCA) anastomosis was investigated with an ultrasonic Doppler flowmeter in 3 patients with sphenoid ridge meningiomas and one with a parasellar malignant teratoma, all of which involved the intracranial internal carotid artery. The intraoperative Doppler flow study revealed a remarkable increase in flow volume of the STA after trial occlusion of the middle cerebral artery in one case and permanent occlusion in two cases. These results substantiate the effectiveness of STA-MCA anastomosis. We also discuss surgical and other contrivances for obtaining sufficient blood supply from this bypass to prevent cerebral ischaemia in the acute phase after elective or accidental occlusion of a major cerebral artery. This is the first report of STA-MCA anastomosis in cases with brain tumour.

Carotid Artery Diseases↗
PubMed1984

[Experimental study on the effect of ultrasonic surgical aspiration on blood flow and nerve function by use of ultrasonic Doppler flowmeter and auditory brainstem evoked response].

The effect of intracranial use of an ultrasonic surgical aspirator on major cerebral vessels and nervous tissue was studied in anesthetised adult cats. Experiments were performed without suction in order to investigate only the effect of ultrasonic emulsification. The flow rate of irrigation saline over the tip of the ultrasonic aspirator was set at either slow (4 ml/min) or fast (24 ml/min). Flow in the common carotid artery and superior sagittal sinus was studied by ultrasonic Doppler flowmetry during direct or indirect (intermediated by muscle fragment) application to the vessels of ultrasonic vibration for periods of 5 min. each in increments of 20% from 20% of maximal intensity. Flow in both the carotid artery and the superior sagittal sinus changed only with direct application on vascular surface of ultrasonic vibration of at least 80% of maximal intensity; otherwise flow in these vessels was not changed. The temperature rise caused by ultrasonic vibration was studied by use of a thermister buried in the brain parenchyma of animals 2 mm from the ultrasonic vibratory probe tip. A rise above the physiological range could be prevented by sufficient irrigation. The effect of ultrasonic vibration on the brainstem was studied by using auditory brainstem evoked response (ABR) to monitor brainstem function. An ultrasonic vibratory probe was applied to the ventral surface of the brainstem exposed by transclival approach. ABR changed noticeably only when ultrasonic vibration of 60% or more of maximal intensity was applied directly; otherwise ABR was not changed. The effect of ultrasonic vibration on the intracranial acoustic nerve was also studied by ABR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

The 19-kDal protein encoded by early region 1b of adenovirus type 12 is synthesized efficiently in Escherichia coli only as a fused protein.

We have constructed recombinant plasmids that direct the synthesis of the Mr 19 000 protein encoded by the adenovirus type 12 (Ad12) E1b region as either a native protein or a protein fused to the amino-terminal portion of the elongation factor EF-TuB in Escherichia coli cells. Using these recombinants, we could synthesize a large amount of the fused protein, while only a small amount of the native Mr 19 000 protein was produced. The failure to synthesize the native Mr 19 000 protein in E. coli cells was ascribed to inefficient translation.

Adenoviridae↗
PubMed1983

Benign familial neonatal convulsions.

A pedigree of so-called benign familial neonatal convulsions was reported. Nine members experienced convulsions in the neonatal period and/or in early infancy. All members except one had good prognosis. One member had mild mental retardation and epilepsy with rolandic EEG foci. It was suggested that some common genetic factors may be involved in the etiology of benign familial neonatal convulsions, convulsions of unknown etiology in infancy (Fukuyama) and epilepsy with rolandic EEG foci. A review of literature revealed that about 14% of cases with benign familial neonatal convulsions eventually developed epilepsy.

Adolescent↗
PubMed1983

A deletion mutant lacking three out of four transfer RNA genes upstream of the coding region of tufB.

Of the two plasmids pTUB1 and pTUB2 constructed by cloning of the 8.9 kb EcoRI fragment carrying tufB (Miyajima, A., Shibuya, M., & Kaziro, Y. (1979) FEBS Lett. 102, 207-210), pTUB2 possesses a deletion of about 0.3 kb. Restriction and sequence analyses have located the deletion in the region of the four tRNA genes thrU-tyrU-glyT-thrT upstream of the tufB structural gene. As a result of homologous recombination between thrU and thrT, the four tRNA genes have been replaced by a single thrU-thrT hybrid gene. The deletion of the three tRNA genes does not significantly alter the in vivo expression of tufB as assessed by the kirromycin-sensitive phenotype of the transformant cells and by the synthesis of EF-Tu in mini-cells. Nor does the deletion affect the synthesis of beta-galactosidase in lysogens carrying a lambda transducing phage with a tufB-lacZ fusion. Transcription of tufB and synthesis of EF-Tu in a cell-free transcription-translation coupled system were essentially the same, regardless of whether pTUB1 or pTUB2 DNA was used as a template. Likewise, 0.2 mM ppGpp inhibits the synthesis of tufB mRNA on both pTUB1 and pTUB2 templates to the same extent. We concluded that the replacement by thrU-thrT hybrid gene of the four tRNA genes upstream of the tufB coding region does not significantly affect either in vivo or in vitro expression of tufB.

Bacteriophage lambda↗
PubMed1982

In vitro construction of the tufB-lacZ fusion: analysis of the regulatory mechanism of tufB promoter.

To investigate the regulatory mechanism of the tufB operon, we have constructed plasmids in which the lac structural genes have been fused to the regulatory region and the 5'-coding sequence of the tufB gene. The fusion was performed by incorporating the 6.6 kb EcoRI-HpaI fragment of plasmid pTUB1, which carried the tufB gene (Miyajima et al. 1979), into the EcoRI and SmaI sites of pMC1403 lac fusion vector (Casadaban et al. 1980). This gene fusion resulted in the production of a hybrid protein consisting of the N-terminal portion (12 amino acid residues) of EF-TuB and the enzymatically active C-terminal half of beta-galactosidase. Bacteria harboring the recombinant plasmid showed a strong Lac+ phenotype. In such a fusion, the lac gene expression was under the control of the tufB promoter. This was evidenced by the following observations; (i) the tufB-lacZ hybrid protein was synthesized constitutively; (ii) its production augmented in parallel with the increase in growth rate; and (iii) on carbon-source upshift, the hybrid protein was produced at a rate 2.5-fold higher than that of the mass increase. Several derivatives of this recombinant plasmid harboring deletions and/or inversions in the tufB regulatory region have been constructed and their properties are described.

Base Sequence↗
PubMed1981

Giant axonal neuropathy: report of two siblings with endocrinological and histological studies.

Giant axonal neuropathy in two siblings was reported. The fact that two cases are found in the same family supports this disorder is genetically determined and recessively inherited. These two cases, similar to the cases reported in literature, had chronic peripheral neuropathy and CNS symptoms, and also petit mal absence and mental retardation in elder sister (case 1) and precocious puberty in younger sister (case 2). Sural nerve biopsies in both cases disclosed axonal swellings or giant axons filled with aggregated neurofilaments, and that aggregated intermediate-sized filaments were found within cytoplasm of Schwann cells, endothelial cells of intra and extra-neurial capillaries and of extra-neurial arterioles, perineurial cells and endoneurial fibroblasts. Skin biopsies in both cases disclosed that aggregated intermediate-sized filaments were also found within cytoplasm of fibroblasts, Langerhans' cells, melanocytes and endothelial cells of capillaries, lymphatic vessels and arterioles. The diagnosis of giant axonal neuropathy can be made only by the findings in skin biopsy.

Adolescent↗
PubMed1981

Effects of a transfusion with a blood substitute (Fluosol-DA, 20%) on cerebral circulation in the monkey.

Local cerebral blood flow (lCBF) and electroencephalogram were monitored in six monkeys after a transfusion using a perfluorochemical suspension (Fluosol-DA, 20%) that has been manufactured as a blood substitute and is known to be synthetic, biologically inert, and nontoxic and to have a high capacity for carrying oxygen. The animals were mechanically ventilated, and blood gases were maintained at physiological levels. Fluosol-DA, 20% was administered either by an exchange transfusion of 20 ml/kg or by an infusion of 8 ml/kg followed by an exchange transfusion of 12 ml/kg. lCBF was measured using the hydrogen clearance technique. An equation was proposed to estimate the tissue-blood partition coefficient of hydrogen; this coefficient is considered to be dependent upon the amount of perfluorochemicals in the blood and was used to calculate lCBF. Systemic blood pressure, pulse rate, central venous pressure, electroencephalogram, and gas analysis of the blood from the femoral artery, the femoral vein, and the superior sagittal sinus showed little change throughout the experiment. lCBF was increased by 12% (p less than 0.005) after the infusion of Fluosol-DA, 20% of 8 ml/kg and by 31% (p less than 0.02) after the exchange transfusion. Hyperventilation reduced lCBF significantly (p less than 0.005), which implies that the reactivity of the cerebral blood vessels to hypocarbia was not impaired by the administration of FLuosol-DA, 20%. Both the results of this study and the physical properties of Fluosol-DA, 20% suggest that this blood substitute can safely be used for normal human brains and that it might also be effective for ischemic brains.

Animals↗
PubMed1981

Experimental study on quantitative flow measurement by a Doppler flowmeter with a sound-spectrograph.

A bidirectional ultrasonic Doppler flowmeter equipped with a sound-spectrographic analyzer has enabled us to determine blood-flow direction and to obtain useful information from the flow pattern in assessing the cerebral blood flow transcutaneously or intraoperatively. Using a regulated flow system produced in a dog, we performed an experimental study in order to establish the optimal mode for its use and to study the reliability in the quantitative cerebral blood-flow measurements. Although we could not measure the absolute blood-flow volume directly with this apparatus, we were able to obtain useful, quantitative information on blood flow and flow pattern by placing the ultrasonic probe in an appropriate position with respect to a blood vessel.

Animals↗
PubMed1980

Venous angiomas of the brain.

Two cases of venous angioma of the brain are presented. Both were discovered by computed tomography and diagnosed by angiography. The lesion was located in the right frontal lobe in 1 case and in the left cerebellar hemisphere in the other. Neither was operated on because of the deep location or extent of the lesion. The 2 cases showed significant angiographic and hemodynamic differences. The literature on venous angiomas of the brain is reviewed. We proposed classifying venous angiomas into two subgroups based on angiographic findings: those with early-appearing vessels and those without. No significant differences in clinical manifestations were noted between these two subgroups in spite of the hemodynamic differences.

Adult↗
PubMed1980

[A case of "cri-du-chat" syndrome with meningomyelocele (author's transl)].

This patients is a 48-day-old girl, born as the third child from a 29-year-old healthy mother. The pregnancy was uneventful, and the delivery was normal. Right after birth, she had episode of asphyxia for several minutes. Her weight of birth was 2,600 g, and the head circumference was 30.4 cm. Dyspnea and cyanosis after feeding were noted on the second day. At the time of admission to our service, she showed typical symptoms of "cri-du-chat" syndrome, namely, characteristic cry, mental retardation (DQ was 48), microcephaly (head circumference was 34.5 cm), rounded face, hypertelorism, oblique palpebral fissures, epicanthus, low-set ears, micrognathia, short neck, simian crease. Other abnormalities such as umbilical hernia, prolapsus ani, dislocation of the hip joint, and lumbosacral meningomyelocele. Cerebral angiogram demonstrated no pathological findings. Pneumoencephalogram showed accumulation of air at the cranial base. Operation was performed for repair of meningomyelocele at the age of 50 days. Postoperative course was smooth.

Chromosomes, Human, 4-5↗
PubMed1979

Neuroradiological aspects of suprasella germinoma.

The plain skull roentgenography, angiography, air encephalography or positive contrast medium ventriculography and computed tomography (CT) of twelve cases of suprasella germinoma were reviewed. In over half of the cases, plain skull roentgenography and angiography showed some abnormalities suggesting a suprasella mass. CT was found to be the most appropriate for routine examination. And air encephalography or positive contrast medium ventriculography offered decisive information.

Adolescent↗
PubMed1978

A new extragenic suppressor of cya mutation. Mutant cyclic AMP receptor protein with an increased affinity for cyclic AMP.

A strain bearing an extragenic suppressor of cya mutation was isolated as a second-site revertant of an adenylate cyclase deficient strain. The mutant was unable to synthesize cAMP but showed normal fermentation profiles and growth properties on a variety of carbon sources. The site of reversion was mapped in, or near, the structural gene for the cAMP receptor protein. Structural alteration of the protein was directly demonstrated by the following biochemical observations: (i) A 10-fold decrease in the dissociation constant for cAMP, (ii) an acidic shift in the isoelectric point, and (iii) the altered binding properties to lambdah80dlac ps DNA.

Carbohydrate Metabolism↗