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Biomedical subjects

K Takamiya

Publications and source records attributed to K Takamiya.

At least 91 records · Page 5Linked to original sources
PubMed1989

Trophic effect of various neuropeptides on the cultured ventral spinal cord of rat embryo.

We studied the trophic effects of various neuropeptides, including substance P (SP), thyrotropin-releasing hormone (TRH), neurotensin (NT) and bombesin (BN) on explanted cultures of ventral spinal cord from 13- to 14-day-old rat embryos. In groups, receiving one type of drug only, there was a significant neurite-promoting effect (NPE) in SP, TRH and BN-treated cultures. At a concentration of 10(-12) M the most potent effect was shown by SP. However, BN had the most potent action at concentrations greater than 10(-10) M. It also became clear that there were maximum and minimum effective concentrations for these 3 neuropeptides. NT had no NPE at any concentration. There was no additional NPE when any two or all four of these neuropeptides were given simultaneously. Our results demonstrate that BN, SP, and TRH have a trophic effect on ventral spinal cord in cultures, and may contribute to a therapeutic strategy in amyotrophic lateral sclerosis.

Animals↗
PubMed1989

Cognitive function in Parkinson's disease: in relation to motor symptoms.

The performance of patients with Parkinson's disease (PD) on selective neuropsychological tests was examined in regard to the applicability of such examinations to diagnosis. Thirty-six patients with PD, and twenty age- and education-matched controls were given a battery of tests designed to assess motor and intellectual functions. The PD group displayed significantly lower scores on all tests than those in the control group. Correlation analyses on the several motor and neuropsychological results in PD group revealed that there was a significant negative correlation between bradykinesia and visuospatial tests, and rigidity and memory tests. Results are discussed with respect to the involvement of dopaminergic pathways in the central nervous system.

Cognition Disorders↗
PubMed1989

Neurotrophic effect of angiotensin II, vasopressin and oxytocin on the ventral spinal cord of rat embryo.

We studied trophic effects of angiotensin II, vasopressin and oxytocin on explanted ventral spinal cord cultures from 13-14-old day rat embryos. There was a significant neurite promoting effect in angiotensin II and vasopressin-treated cultures. Angiotensin II had the most potent effect at any concentrations. It became clear that minimum effective concentration was 10(-8) M in angiotensin II and vasopressin respectively. Effect of these two neuropeptides was concentration-dependent. However, oxytocin had no neurotrophic effect at any concentrations. Our results demonstrated that angiotensin II and vasopressin have a neurotrophic effect on ventral spinal cord in cultures, and may contribute to therapeutic strategy of amyotrophic lateral sclerosis.

Angiotensin II↗
PubMed1989

Cognitive function in multiple sclerosis and its relation to functional abilities.

The performance of patients with multiple sclerosis (MS) on selected neuropsychologic tests was examined to ascertain the applicability of such examinations to diagnosis. Twenty-four patients with definite or probable MS, and sixteen age- and education-matched control subjects were given a battery of tests to assess intellectual functions. The results indicate that the MS patients had cognitive impairment. Severity of disability was not significantly correlated with cognitive impairment. Impaired cognitive functioning, which is often not detected through routine examination, may occur in the disease. These deficits may represent manifestations of otherwise undetectable plaques in the subcortical white matter.

Adult↗
PubMed1989

["Drop hand" resulting from cerebral infarction--case report].

A 52-year-old male was admitted with the progressive weakness of the right 3rd, 4th and 5th fingers on three days after the onset. On admission, his right hand and all of right fingers were flexed. Any extension of the right hand and any movement of right fingers were not accomplished. The sensory deficit in the right wrist joint was not observed. Initial computed tomography (CT) scan of the brain carried out on the day of admission could not detect any abnormal findings. However, the follow-up CT scans demonstrated the localized low density lesion in the left frontoparietal area. MR imaging also revealed abnormality attributable to cerebral infarction. Diagnosis of "Pseudoradial nerve palsy" was made. The mechanisms of these neurological deficits and the problems in differential diagnosis between central and peripheral nerve involvements were discussed.

Cerebral Infarction↗
PubMed1989

[CT evidence of high density area in bilateral striatum secondary to anoxia].

We recently observed a patient in whom basal ganglia calcification (BGC) was demonstrated on sequential CT scans only 9 days after the anoxic episode. A 58-year-old woman had a history of diabetes mellitus for 23 years for which she was treated with insulin. She had a operation for retinal detachment under local anesthesia. Two days after the operation, she developed dyspnea, and was referred to our department. She was intubated, and respiratory support was begun. On neurological examination, she was semicomatose, and intermittent spontaneous movements involved in all extremities. The pupils were 3 mm in diameter, equal and responsive. Full doll's eye responses were obtained both horizontally and vertically. Deep tendon reflexes were hyperactive bilaterally without ankle jerks and extensor plantar responses. Arterial blood gas levels revealed a PaO2 of 49 mmHg, PaCO2 38 mmHg: pH 7.16. Serum Ca, P, Mg, Al-p and parathyroid hormone levels were normal. The EEG was isoelectric. Although the initial CT scan was normal, the subsequent CT scan 9 days later showed extensive high density change of the striatum, which was assumed to be BGC due to anoxia was briefly discussed.

Basal Ganglia Diseases↗
PubMed1989

[A case with polymyositis associated with primary hyperparathyroidism].

A 67-year-old woman was admitted to our department because of 5 years' duration of proximal muscle weakness. Serum CK was high, and EMG showed myogenic pattern, and muscle biopsy revealed remarkable inflammatory cells infiltrating around the destroyed muscle fibers. Her muscle weakness and hyperCKemia markedly improved by corticosteroid therapy, suggesting that the diagnosis was compatible with polymyositis (PM). In addition, serum calcium was high and phosphate was low. Serum parathormone level significantly elevated. The findings of diagnostic imaging procedures including echography, scintigraphy, and computed tomography of the parathyroid glands suggested presence of parathyroid adenoma with cystic degeneration in the thyroid tissue. There was only one case report of PM associated with primary hyperparathyroidism (PHP) as the literature referred. In this case, we could not prove direct relationship between PM and PHP. The association might have been coincidental. However, PHP might have played some role in the pathogenesis of muscular involvement, or there might be a similar immunological mechanism as seen between PM and malignancy. It is possible that association of PM and PHP is more frequent than generally considered. It may be necessary to pay more attention to find out the association of PM and PHP.

Adenoma↗
PubMed1988

Effect of various polyamine analogs on in vitro polypeptide synthesis.

Various polyamine analogs were examined for their ability to stimulate and to function as sparing agents for the Mg2+ requirement in polypeptide synthesis at various temperatures in Escherichia coli (37 and 47 degrees C) and the extremely thermophilic Thermus thermophilus (60 and 70 degrees C) cell-free systems. The optimal concentration of each polyamine analog increased as the incubation temperature was elevated. At a fixed temperature, the optimal concentration of polyamine analogs was in the order diamines greater than triamines greater than tetraamines greater than pentaamines. All diamines tested stimulated polypeptide synthesis almost equally but lowered the optimal Mg2+ concentration in the order diaminopropane greater than putrescine greater than cadaverine. The degree of diamine stimulation was maximal at 37 degrees C. The effects of three triamines were very similar in the E. coli system but in the T. thermophilus system spermidine was most effective in stimulation of polypeptide synthesis. From the results of experiments using tetraamines and pentaamines, it was deduced that the presence of both aminobutyl and aminopropyl groups in polyamine analogs is important for stimulation of polypeptide synthesis. In the E. coli system, triamines were the most effective polyamines for stimulation of polyphenylalanine synthesis at both 37 and 47 degrees C, while, in the T. thermophilus system, thermospermine, a tetraamine, was most effective at 60 degrees C and 3,4,4,3-pentaamine was most effective at 70 degrees C.

Cell-Free System↗
PubMed1988

Enzymatic properties of ubiquinol:cytochrome c2 oxidoreductase in situ in Rhodopseudomonas palustris membranes.

The presence of ubiquinol:cytochrome c2 oxidoreductase was shown in the membranes from a photosynthetic bacterium, Rhodopseudomonas palustris. Some properties of the enzyme in situ were investigated. The optimal pH of this enzyme activity was 7.0 in the intact membranes. The activity was inhibited by both antimycin and myxothiazol. Maximal activity (Vmax) was 3-4 mol cytochrome c (c2) reduced/mol cytochrome c1.s. Apparent activity of the enzyme with horse heart cytochrome c as the electron acceptor decreased as the concentration of salts in the reaction mixture increased, whereas when R. palustris cytochrome c2 was used as the electron acceptor, the activity increased as the concentration of salts increased. Moreover, the activity of the enzyme did not depend on the species or concentration of anions but on both the concentration and valency of the cations of the salts. These salt effects were thought to be due to the change of effective concentration of cytochrome molecules caused by cations near the membrane surface, which was net negatively charged. Apparent Km for ubiquinol-1 was about 80 microM irrespective of the species of cytochrome and the presence of salts.

Animals↗
PubMed1988

Trimethylamine N-oxide respiration by aerobic photosynthetic bacterium, Erythrobacter sp. OCh 114.

Erythrobacter sp. OCh 114, an aerobic photosynthetic bacterium, had trimethylamine N-oxide (TMAO) reductase activity, which increased when the culture medium contained TMAO. The reductase was located in the periplasm. The bacteria grew anaerobically in the presence of TMAO. These results suggested that Erythrobacter OCh 114 has the ability to reduce TMAO through the respiratory chain. The TMAO respiration system of this organism was different from those of facultative purple photosynthetic bacteria in two respects: (a) TMAO reductase did not have activity to reduce dimethyl sulfoxide and (b) soluble c-type cytochrome, cytochrome c551, and cytochrome b-c1 complex appeared to be involved. The photochemical activity, which is usually inoperative in the anaerobic cell suspension, was restored by TMAO, suggesting that the photosynthesis and the TMAO respiration share a common electron transfer chain.

Bacteria, Aerobic↗
PubMed1988

Roles of bacteriochlorophyll and carotenoid synthesis in formation of intracytoplasmic membrane systems and pigment-protein complexes in an aerobic photosynthetic bacterium, Erythrobacter sp. strain OCh114.

Synthesis of bacteriochlorophyll and carotenoids was inhibited in an aerobic photosynthetic bacterium, Erythrobacter sp. strain OCh114, by alpha, alpha'-dipyridyl and diphenylamine. Formation of two pigment-protein complexes, reaction center-B870 (RC-B870) and B806, and development of the intracytoplasmic membranes of the cells were studied by spectral analysis and electron microscopy. Inhibition of bacteriochlorophyll synthesis by alpha, alpha'-dipyridyl, which was accompanied by a decrease in carotenoid synthesis, suppressed formation of intracytoplasmic membranes in the cells. Growth under illumination had a similar effect on formation of pigments and membranes. On the other hand, inhibition of carotenoid synthesis by diphenylamine did not suppress either development of the membrane system or bacteriochlorophyll synthesis. Formation of RC-B870 and B806 complexes, however, was differentially affected by blockage of carotenoid synthesis. In the presence of diphenylamine, the B806 complex was formed in a much smaller amount than the RC-B870 complex. These results suggest that, in Erythrobacter sp. strain OCh114, bacteriochlorophyll plays an essential role in intracytoplasmic membrane development, and carotenoids are important for assembly of pigment-protein complexes.

Aerobiosis↗