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Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 775 records · Page 43Linked to original sources
PubMed1986

[Longitudinal study on circadian rhythms of plasma hormone levels during Japanese Antarctic Research Expedition].

Circadian rhythms of plasma cortisol, aldosterone and testosterone levels were studied longitudinally in a member of the 21st Japanese Antarctic Research Expedition during periods of one year both in Antarctica and in Hokkaido, Japan. Results were as follows. Plasma cortisol, aldosterone and testosterone levels of man both in Antarctica and in Hokkaido showed average patterns of rhythmicity which were similar to respective Aschoff's standard curves with an exception of testosterone rhythm pattern in Hokkaido. Monthly mean plasma cortisol level diminished markedly in June, the month of darkness throughout the day, but normal circadian rhythm of cortisol level was maintained even during this period. However in Japan the seasonal fluctuation of monthly mean plasma cortisol level was small and had no correlation with the environmental temperature and solar rhythm. Monthly mean plasma aldosterone level increased markedly in July, dark winter month and also in December, the month of midnight sun in Antarctica. In Japan also the same kind of seasonal fluctuation which showed peaks in winter and summer was observed. Monthly mean plasma testosterone level increased markedly in June, the month of darkness in Antarctica. However little seasonal fluctuation was observed in Japan. These findings suggest that social factors rather than light-dark cycle act as a Zeitgeber effective for the maintenance of circadian rhythms of human circulating hormone levels.

Adult↗
PubMed1986

[In vitro predictive activity assay of agents based on dynamic cellular morphological findings--clinical application].

The antitumor activity and mode of action of antitumor agents were assayed by a new method which takes a relatively short time for evaluation. The method was clinically applied to patients with malignant lymphoma or acute leukemia for estimating drug sensitivity. Fresh malignant cells were obtained from patients' bone marrow, lymph nodes, or peripheral blood using Lymphoprep methods in 26 patients with these malignant disorders. Each sample (5 X 10(5) cells/ml) was cultured in the medium with RPMI 1640 supplemented with 10% of FCS and 20% of patients' own sera containing every antitumor agent at predetermined concentrations for 30 minutes. Each sample was again cultured for another 72 hours at 37 degrees C in a 5% CO2 humidified atmosphere after rinsing. Microscopic observation was periodically carried out using a specially devised observation chamber with an inverted immersion microscope for 72 hours. Morphological changes of 200 to 300 cells of each sample were described according to morphological criteria. Of these, irreversible changes in number were considered to be indicative of antitumor activity of the agent tested. More than 50% cellular damage was categorized as effective and more than to 50% reduction of leukemia cells or decrease in size of lymph nodes the same degree in malignant lymphoma were considered to be clinically effective. Forty-four assay runs in 26 patients were done, and on 31 occasions were shown to be coincident. We conclude that this in vitro method is fully applicable for predicting the effectiveness of an agent to be clinically administered regardless of the various controversial problems to be solved.

Adolescent↗
PubMed1986

[Tuberous sclerosis with intraventricular tumor: report of 2 cases].

It is well known that intraventricular tumors are occasionally seen in patients with tuberous sclerosis. We have experienced two cases of tuberous sclerosis with intraventricular tumor. Case 1: an 8-year-old girl was admitted to our clinic because of headache and vomiting of one month's duration. She had adenoma sebaceum, mental retardation and seizures clinically, and a large tumor was found in the right lateral ventricle by pneumoventriculography. Partial removal of the tumor was performed by the right frontal transcortical approach, but she later died of pneumonia. Necropsy revealed hamartomatous disease characterized by multiple focal tumor-like malformations in various organs including the brain, kidneys, heart, lungs and liver. The histological diagnosis of the intraventricular tumor was subependymal giant cell astrocytoma. Case 2: a 6-year-old boy was admitted to our clinic because of headache of one year's duration. He had also suffered from seizures since 6 months of age. Adenoma sebaceum was noted in the cheeks. CT revealed a medium sized tumor at the right foramen of Monro and the moderately dilated right lateral ventricle and several calcified deposits in the lateral ventricle wall. The tumor was subtotally removed by the right frontal transcortical approach. The pathological examination showed subependymal giant cell astrocytoma. Now 6 years after the operation he is enjoying a normal school life. In our cases, intraventricular tumors associated with tuberous sclerosis were of a typically benign histological appearance, that is subependymal giant cell astrocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Astrocytoma↗
PubMed1986

[Effect of calcium antagonist (diltiazem) on symptomatic cerebral vasospasm--with special reference to CT classification].

CT is important for detecting subarachnoid clots and intracerebral or intraventricular hemorrhage. The presence of subarachnoid clots surrounding the cerebral arteries may be one of the causes of cerebral vasospasm. It is agreed that there is a correspondence between the site of subarachnoid clots and the location of cerebral vasospasm. The authors have already reported that the appearance and severity of symptomatic cerebral vasospasm were not affected by calcium antagonists (Diltiazem), but the prognosis improved significantly for 105 patients (especially Hunt-Hess grade II and III) at the 3-month follow-up examination. In this study, the above 105 patients, each with a ruptured supratentorial aneurysm, were classified preoperatively according to Fisher's CT grading system and the effect of Diltiazem was re-examined. Patients in Hunt-Hess grade V were excluded and the duration of treatment with Diltiazem was 2 weeks following the operation. 105 cases (Diltiazem) were compared as a control group with 100 cases who were operated on before the administration of Diltiazem. The frequency of occurrence of symptomatic cerebral vasospasm tended to decline in patients with a CT grade of 2 or 3, and the prognosis improved significantly for 105 patients including 32 cases with symptomatic cerebral vasospasm. The preliminary results here indicate that Diltiazem might be especially effective for patients of Hunt-Hess grade II and III with CT grades of 2 and 3.

Adult↗
PubMed1985

The structure of arthropod hemocyanins.

Hemocyanins are large multi-subunit copper proteins that transport oxygen in many arthropods and molluscs. Comparison of the amino acid sequence data for seven different subunits of arthropod hemocyanins from crustaceans and chelicerates shows many highly conserved residues and extensive regions of near identity. This correspondence can be matched closely with the three domain structure established by x-ray crystallography for spiny lobster hemocyanin. The degree of identity is particularly striking in the second domain of the subunit that contains the six histidines which ligate the two oxygen-binding copper atoms. The polypeptide architecture of spiny lobster hemocyanin appears to be the same in all arthropods. This structure must therefore be at least as old as the estimated time of divergence of crustaceans and chelicerates, about 540 to 600 million years ago.

Amino Acid Sequence↗
PubMed1985

Mesectodermal leiomyoma of the ciliary body. An ultrastructural study.

Electron microscopic observation of a mesectodermal leiomyoma of the ciliary body, in which clear perinuclear halos were present, revealed the ultrastructural characteristics of smooth muscle cells, which include myofilaments with fusiform densities, dense attachments, external lamina, and pinocytotic vesicles. In addition, fibrillary cytoplasmic processes containing large numbers of myofilaments with fusiform densities were notably arranged in a neurogenic pattern when observed under a light microscope. These are characteristic of and specific to mesectodermal leiomyomas. Masses or cords of large, polygonal cells with clear halos surrounding the large, round-to-oval nuclei were found to contain only a few myofilaments. Such features are atypical of mesectodermal leiomyomas. Melanocytes were scattered throughout the tumor, providing additional evidence for the neural crest theory of origination of mesectodermal leiomyomas, since melanocytes are well-recognized descendants of the neural crest. A small number of lipid droplets, abundant lysosomes, and, occasionally, phagosomes were also observed in the cells of this mesectodermal leiomyoma.

Actin Cytoskeleton↗
PubMed1985

Fatty acids and fatty alcohols of wax esters in the orange roughy: specific textures of minor polyunsaturated and branched-chain components.

Open-tubular gas chromatography was carried out on fatty acids and alcohols obtained from wax esters of the orange roughy, Hoplostethus atlanticus, caught at sea off New Zealand. The major (above 5%) components were 16:1(n-7), 18:1(n-9) and (n-7), 20:1(n-9) and (n-7), and 22:1(n-11, n-13) as fatty acids, and 16:0, 18:0, 18:1(n-9), 20:1(n-9) and (n-7), and 22:1(n-11, n-13) as fatty alcohols. The total percentages of the minor components were 10% in the acids and 26% in the alcohols. The 22:1/20:1 ratio of the fatty alcohols obtained in this study was less than 1.0, although the ratio for the Atlantic orange roughy has been reported as being greater than 1.0. The contents of polyenes were as low as 2.48% in the acids and 0.95% in the alcohols, but their compositions showed some specific features. The percentages of the C16-C22 dienes in the total polyenes were remarkably high, 57.7% of these acids and 53.1% of these alcohols. The most important dienes were 18:2(n-6) in the acids and 20:2(n-6) in the alcohols.

Animals↗
PubMed1985

Separation of cross-linked products of rat tail tendon collagen from monomeric components by gel chromatography in the presence of Tris dodecyl sulfate at 4 degrees C.

Rat tail tendon collagen can be solubilized by a neutral aqueous solution containing 2% Tris dodecyl sulfate at 4 degrees C without being unfolded to its constituent polypeptides. The solvent at this temperature is particularly suited for gel chromatographic separation of native collagen. Thus Sepharose CL-2B gel chromatography was found to separate the monomeric collagen molecule from the products of intermolecular cross-linking. The procedure can be effectively used to follow progress of intermolecular cross-linking with aging. The monomeric collagen can be subsequently applied to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate to evaluate the mode of intramolecular cross-linking.

Animals↗
PubMed1985

Computed tomography of a diploic epidermoid cyst of the skull.

The computed tomographic (CT) and other roentgenological characteristics of a skull diploic epidermoid cyst in a 14-year-old boy with Ito syndrome, a neurocutaneous syndrome, are presented. When this boy was 3 years 10 months of age, a plain roentgenogram of the skull showed an area of decreased density in the left parietal bone. The area has grown for the subsequent 10 years plus and a characteristic sclerotic margin has become evident. CT examination showed a cystic lesion in the diploe, the outer third of high density and the inner third low density. CT allowed prediction of the operative and histological findings. It was useful not only for the diagnosis but also in the pathogenesis.

Adolescent↗
PubMed1985

Oxytocin in the cerebrospinal fluid and plasma of pregnant and nonpregnant subjects.

The oxytocin concentration in the cerebrospinal fluid (CSF) and plasma of pregnant women at term with and without labor pain were measured by radioimmunoassay and compared with those of non-pregnant women of matched age. The oxytocin concentrations in the CSF were 4.9 +/- 4.1 microU/ml (mean +/- S.D.) in pregnant women with labor pain, 4.1 +/- 2.4 microU/ml in those without labor pain and 4.0 +/- 2.8 microU/ml in nonpregnant women, and the oxytocin concentrations in the plasma of these subjects were 45.2 +/- 19.6, 17.1 +/- 22.2 and 7.0 +/- 5.3 microU/ml, respectively. Thus the oxytocin level in the CSF did not change appreciably even when the level in the plasma was raised in the pregnant women with labor pain. These findings suggest that oxytocin does not penetrate the blood-brain barrier, and that oxytocin in the CFS has little or no central role in parturition in women.

Adult↗
PubMed1985

Ultrastructure of human umbilical artery and vein. Characterization and quantification of lipid laden cells.

Intimal thickening and lipid accumulation, which occur in atherosclerosis, were observed in fifteen human umbilical vessels. Quantification of lipid laden cells was done electron-microscopically. Within 1 month after birth, lipid laden cells originating from macrophages were observed in the umbilical artery, while those originating from smooth muscle cells were seen in the umbilical artery and vein. Lipid droplet formation appeared to be independent and different in macrophages and smooth muscle cells; the latter cells were stimulated to produce lipid droplets by hypoxia and the former cells by blood components.

Age Factors↗
PubMed1985

Isolation of a versatile Serratia marcescens mutant as a host and molecular cloning of the aspartase gene.

An extracellular nuclease-deficient, antibiotic-sensitive, and restrictionless mutant was isolated from the wild-type strain of Serratia marcescens Sr41 by four rounds of mutagenesis. The mutant was transformed efficiently with plasmid DNAs prepared from Escherichia coli and S. marcescens, and was used as a host for the cloning of the aspartase gene (aspA+) of S. marcescens. Cells carrying the cloned aspA+ gene on a multicopy plasmid produced ca. 39-fold more aspartase than did control cells, and the level of enzyme overproduction was in proportion to the copy number of the aspA+ recombinant plasmid. Aspartase was identified as a polypeptide of molecular weight 52,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Ammonia-Lyases↗
PubMed1985

Microangiographic findings of massive intestinal bleeding in a patient with Crohn's disease: a case report.

A 16 year old man with complaints of abdominal pain, diarrhea, high fever and loss of body weight was made a diagnosis of Crohn's disease. During the administration, he had intestinal obstruction and several episodes of massive intestinal bleeding. Selective angiography of the superior mesenteric artery demonstrated the bleeding site in the ileum. Microangiography of the surgical specimens revealed abrupt interruptions of arteriae rectae in the submucosa indicating the bleeding site from the diseased intestine.

Adolescent↗