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Biomedical subjects

K Yagi

Publications and source records attributed to K Yagi.

At least 289 records · Page 16Linked to original sources
PubMed1995

[Parasitologic significance of the alteration of the causative Anisakidae worm and of the Pseudoterranova decipiens female immature adult worm, casting off the cuticles, and excreted from human in Kanazawa City].

We have been studying Anisakidae larvae, their intermediate hosts and their final hosts in the northern Japan Sea area. These larvae cause anisakidosis. According to the investigation, the recent burst of pseudoterranovosis in this area can be attributed to the increased presence of sea lions, which proliferate in the Arctic region, then migrate to the northern Japan Sea and eat the intermediate host fish. In a stomach of a male sea lion that was captured in February 1995, we found more than 4,500 Pseudoterranova decipiens. Although there is no known circumstance in which a human would consume an adult worm of Anisakis nematode, an astonishing case of this was found in Kanazawa; a female young adult Pseudoterranova decipiens undergoing the final metamorphosis was emitted from a patient. This indicates that the Anisakis larva can mature into the adult worm in humans. It is postulated that the Pseudoterranova decipiens larva is in the process of adapting to use humans as the final host.

Adult↗
PubMed1995

Difference in effects of classic and phospholipid hydroperoxide glutathione peroxidases on liver lipid peroxide level in selenium-deficient rats.

When weanling male rats of the Wistar strain were fed a selenium-deficient diet, the activity of classic glutathione peroxidase (GPx) in liver cytosol decreased rapidly. In contrast, the activity of phospholipid hydroperoxide GPx (PHGPx) in the cytosol decreased only slowly. Despite the marked decrease in classic GPx activity, the lipid peroxide level in the liver did not change until 6 weeks after the start of the feeding, whereas the level was significantly increased by 9 weeks, by which time PHGPx activity and its protein level had markedly diminished. These data indicate that PHGPx is much more crucial than classic GPx in preventing the elevation of liver lipid peroxide level in selenium-deficient rats.

Animals↗
PubMed1995

[Surgery for intractable epilepsy--selection and presurgical evaluation].

Success in epilepsy surgery depends upon the exact localization of epileptogenic lesion identified by recordings of scalp and/or intracranial EEG and observation of clinical seizures in addition to the neuroimaging techniques such as CT, MRI, SPECT, PET. Thinking of the postoperative outcome in the literatures regarding epileptic seizures according to surgical procedure, main candidates for surgery are patients with intractable symptomatic localization-related epilepsies. Walker's criteria (1974) are generally agreed as selection criteria of candidate for epilepsy surgery. In our hospital, candidates for temporal lobe resection are selected according to the following criteria: 1) presence of an epileptogenic region presumably within the temporal lobe, 2) appropriate drug treatment for at least 5 years, 3) complex partial seizures more frequently than once a week, 4) adolescent or adult patients over 15 years of age with no persistent psychiatric symptoms, and 5) patients capable of social rehabilitation if recurrent seizures subside. Presurgical evaluation consists of noninvasive and invasive evaluation. Noninvasive evaluation includes neuro-psychological tests including Wada test, neuroimagings, interictal and ictal long-term intensive EEG/CCTV monitoring by the scalp EEG using 10/20 electrode placement as well as sphenoidal electrode to catch at least 3 spontaneous seizures. Invasive evaluation is interictal and ictal long-term intensive EEG/CCTV monitoring by intracranial electrodes for two weeks. The presurgical evaluation is performed by the team composed of neurosurgeon, neurologist, neuropsychiatrist, and neuropediatrician to decide the localization of epileptogenic lesions for resection. Outcome concerning seizure, neuropsychological aspects, and QOL is followed for more than 3 years after operation. Surgery for epilepsy should not be done without strict presurgical evaluation.

Adolescent↗
PubMed1994

Involvement of ecto-ATPase as an ATP receptor in the stimulatory effect of extracellular ATP on NO release in bovine aorta endothelial cells.

The secretion of nitric oxide (NO) was stimulated by the addition of ATP or ADP, but not by AMP or adenosine, in cultured bovine aorta endothelial cells. Inhibitors of ecto-ATPase, NaN3 and Ap5A, significantly inhibited the stimulation, while an inhibitor of P2Y-purinoceptor and ecto-ATPase, RB2, completely suppressed it. A non-hydrolyzable ATP analogue, AMP-PNP, stimulated NO release; the stimulation was completely suppressed by RB2 but not by NaN3 and Ap5A. Therefore, only P2Y-purinoceptor was involved in the stimulation by AMP-PNP, while both ecto-ATPase and P2Y-purinoceptor were involved in the stimulation by ATP and ADP. It is not clear whether the stimulation is dependent on the dephosphorylation activity of ecto-ATPase or not, but the enzyme appears to act as an ATP and ADP receptor for signal transduction through adenine nucleotides.

Adenosine Diphosphate↗
PubMed1994

Cloning and chromosomal mapping of the human nonfunctional gene for L-gulono-gamma-lactone oxidase, the enzyme for L-ascorbic acid biosynthesis missing in man.

Man is among the exceptional higher animals that are unable to synthesize L-ascorbic acid because of their deficiency in L-gulono-gamma-lactone oxidase, the enzyme catalyzing the terminal step in L-ascorbic acid biosynthesis. In the present study, we isolated a segment of the nonfunctional L-gulono-gamma-lactone oxidase gene from a human genomic library, and mapped it on chromosome 8p21.1 by spot blot hybridization using flow-sorted human chromosomes and fluorescence in situ hybridization. Sequencing analysis indicated that the isolated segment represented a 3'-part of the gene, where the regions corresponding to exons VII, IX, X, and XII of the rat L-gulono-gamma-lactone oxidase gene remain with probable deletion of the regions corresponding to exons VIII and XI. In the identified exon regions were found various anomalous nucleotide changes, such as deletion and insertion of nucleotide(s) and nonconformance to the GT/AG rule at intron/exon boundaries. When the conceptual amino acid sequences deduced from the four exon sequences were compared with the corresponding rat sequences, there were a large number of nonconservative substitutions and also two stop codons. These findings indicate that the human nonfunctional L-gulono-gamma-lactone oxidase gene has accumulated a large number of mutations without selective pressure since it ceased to function during evolution.

Amino Acid Sequence↗
PubMed1994

Efficient transfection of human interferon-beta gene to human glioma cells by means of cationic multilamellar liposomes coupled with a monoclonal antibody [corrected].

We have been devoting our efforts to develop the useful liposomes that have high potentials of gene transfer and we aim human gene therapy for malignant glioma with cytokine genes. In our previous study, we prepared our original reverse-phase evaporation vesicles (REV) by an improved procedure of reverse-phase evaporation method. However, this procedure was very complicate. In this paper, a simple procedure for the preparation of cationic multilamellar vesicles (MLV) was introduced, and efficient expression and growth-inhibitory effect of MLV with entrapped human interferon-beta gene to glioma cells was comparable to that obtained with REV. Considering the present experiments, MLV seem to be more preferable for clinical application.

Brain Neoplasms↗
PubMed1994

Effects of a histamine H2-receptor antagonist, ranitidine on the vasopressin and oxytocin responses to novelty stress in the rat.

Effects of an intraperitoneally (i.p.) administered histamine H2-receptor antagonist, ranitidine, on plasma levels of vasopressin and oxytocin were studied in male rats under unstressed or stressed conditions. In the rats injected i.p. with the vehicle (saline) solution, plasma vasopressin level was significantly lower and plasma oxytocin level was significantly higher after weak electric foot shocks (10 ms pulses of 0.8 mA, 50 Hz and 1 s duration, repeated at 30 s intervals for a period of 5 min) than those levels in the unshocked control rats. Ranitidine injected i.p. at a dose of 100 mg per kg body weight blocked the suppressive vasopressin but not the facilitatory oxytocin response to the shocks. Novel environmental stimuli were applied to rats in such a way that the animals were transferred to an experimental room, placed in a white-painted plastic pail and administered an intermittent 2 kHz and 70 dB pure tone of 2 s duration that was repeated at 10 s intervals for 2 min. In the rats injected i.p. with the vehicle solution, plasma vasopressin level was lower and oxytocin level was higher after the novel stimuli than in the unstimulated control rats. Ranitidine injected i.p. at a dose of 100 mg per kg body weight blocked the suppressive vasopressin but not the facilitatory oxytocin response to the novel stimuli. Ranitidine administered i.p. at doses of 10, 20, 50 and 100 mg per kg body weight was tested for the suppressive vasopressin response to the novel stimuli given for periods of 2 or 5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Bromide, in the therapeutic concentration, enhances GABA-activated currents in cultured neurons of rat cerebral cortex.

We investigated the effect of bromide on gamma-aminobutyric acid (GABA)-activated currents in cultured cerebral neurons of the rat, employing whole-cell voltage- and current-clamp techniques. Application of 100 microM GABA elicited currents whose reversal potential was 0 mV with equal concentrations of chloride in both pipette and bath solutions and more negative than -60 mV with 159 mM chloride extracellularly and 4 mM chloride inside. Bicuculline blocked the currents. These findings showed that the currents were composed of chloride flux through GABAA receptor-coupled channels. Reversal potential revealed a permeability ratio of bromide with respect to chloride (PBr/PCl) of 1.51. When 100 microM GABA was applied with the extracellular solution containing 140 mM bromide and 19 mM chloride, the currents were enhanced 2.00- and 1.91-fold at the holding potentials of -20 mV and 0 mV, respectively. Extracellular solutions containing various concentrations of bromide substituted for the same amount of chloride were applied with 100 microM GABA. The therapeutic concentration of 10 mM and 20 mM bromide enhanced the currents 1.28- and 1.36-fold of the control currents at the holding potential of -20 mV, respectively. Under current-clamp recording, a larger hyperpolarization was obtained by the application of GABA with a 140 mM bromide-containing solution. These findings suggest that bromide potentiated GABA-activated currents at the therapeutic concentrations ranging from 10 mM to 20 mM, causing the larger GABA-induced hyperpolarization. It is postulated that the antiepileptic effect of bromide might occur through the potentiation of inhibitory postsynaptic potentials elicited by GABA.

Animals↗
PubMed1994

Omentoplasty for postpneumonectomy bronchopleural fistulas.

Postpneumonectomy fistula is one of the most serious complications in general thoracic surgery and remains difficult to manage. From 1984 to 1991, we successfully used pedicled omentum for the treatment of postpneumonectomy bronchopleural fistulas (omentoplasty) in five patients, four of whom had thoracic empyema. For bronchopleural fistulas without early postoperative infection, single-stage closure was performed which was then covered with pedicled omentum. Omentoplasty was performed successfully in patients with thoracic empyema, after open or closed drainage. Open thoracotomy was useful when closed drainage was ineffective. Even after open thoracotomy, closure of the wound was achieved. All five patients could be discharged. Omentoplasty was useful in the therapy of postpneumonectomy bronchopleural fistula even in the presence of thoracic empyema.

Aged↗
PubMed1994

Assessment of the proliferative activity and radiosensitivity of human tumours using the cytokinesis-block micronucleus assay.

We established an in vitro cytokinesis-block micronucleus assay of human tumours for estimation of the proportion of cells undergoing mitosis (the dividing fraction, DF), the time for the number of nuclei to double and the radiosensitivity in terms of the micronucleus frequency, based on a concept described previously. Under certain conditions, the nuclear number doubling time (NNDT) was considered to represent the potential doubling time. Tumour specimens obtained at surgery were disaggregated into single-cell suspensions and were directly cultured in the presence of cytochalasin B with or without irradiation. At various intervals, the percentage of multinucleate cells (the plateau value represented the DF), the average number of nuclei per cell and the number of micronuclei in binucleate cells were determined. DF and NNDT values were obtained in 58 of the 73 tumours investigated, and the micronucleus frequency was obtained in 54 of these 58 tumours. The DF ranged from 4.1% to 71% and the NNDT ranged from 3.1 to 83 days. A DF > or = 20% was associated with a higher recurrence rate in patients undergoing curative operation. A correlation was found between the NNDT and the time to relapse in patients with recurrent disease. The average number of micronuclei per binucleate cell at 2 Gy of irradiation (after subtraction of the value at 0 Gy) ranged from 0.052 to 0.35. Tumours which produced more micronuclei after irradiation showed a better response to radiotherapy. This assay can be readily performed on human tumours and appears to have promise as a predictive assay for radiation therapy.

Adenocarcinoma↗
PubMed1994

Onchocerca suzukii n. sp. and O. skrjabini (= O. tarsicola) from a relict bovid, Capricornis crispus, in Japan.

The species from the tendons and sub-cutaneous tissue of the tarsal and carpal joints is identified as O. skrjabini Rukhlyadev, 1964 (this taxon, which was poorly defined and badly restored, is used instead of O. tarsicola to avoid dispute). O. skrjabini belongs to on homogeneous group of four species parasitic in Palearctic cervids, which seems to have evolved relatively recently. The morphological characteristics of the parasite of Capricornis are not sufficient to warrant the creation of a new taxon. The species from the subcutaneous tissue of the body is named O. suzukii n. sp. It belongs to a group comprising three species, parasites of antilocaprids and cervids from the Holarctic region and tropical domestic bovines, which seem to have evolved before the skrjabini group. The Japanese species does not present the hypertelic characters of the other species of the group. The microfilaria of O. suzukii is unknown. Thus it is not possible to say if this species is the same as one found in bovines (and, perhaps, in humans) in the Oita region of Kyushu Island.

Animals↗
PubMed1994

Improvement of quality-of-life following resective surgery for temporal lobe epilepsy: results of patient and family assessments.

In order to evaluate the quality-of-life (QOL) of epilepsy surgery patients, we surveyed patients' degree of life satisfaction and their families' degree of satisfaction with patient's status in a range of domains both pre- and post-operatively. Of 100 patient-family sets of surveys that were mailed out, 93 were completed and returned from patients and 91 from their families. All patients surveyed had temporal lobe epilepsy and had been followed for longer than 2 years after resective surgery. Patients and their families rated overall QOL as having markedly improved following surgery. However, they rated social domains of QOL, including role activities, financial status, and social and family relationships as having improved relatively little. Despite freedom from seizures, a few patients' families were dissatisfied with the patients' post-operative status, primarily for psychosocial reasons. Patients operated on at a later age reported little gains in life satisfaction following surgery. This study supports the conclusion that surgical intervention should occur before patients are subjected to the psychological conflicts and social handicaps associated with chronic intractable epilepsy.

Adaptation, Psychological↗
PubMed1994

Transient erythroblastopenia due to human parvovirus B19 infection: a case report of a boy suffering from purpura.

Transient erythroblastopenia of childhood (TEC) was observed in a boy infected by human parvovirus B19 (B19) before the manifestation of the typical clinical picture of erythema infectiosum (EI). He did not have any apparent symptoms of anemia, and spontaneous resolution of erythroblastopenia was observed before the manifestation of the symptoms of EI. The difference between primary B19 infection and classical TEC is discussed.

Child↗