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Biomedical subjects

K Yagi

Publications and source records attributed to K Yagi.

At least 343 records · Page 19Linked to original sources
PubMed1993

Effects of novelty stress on vasopressin and oxytocin secretion by the pituitary in the rat.

Effects of novel environmental stimuli on vasopressin and oxytocin secretion by the pituitary were studied in dehydrated male rats. As the novel environmental stimuli, rats were transferred to an experimental room, placed in a box painted black and given a pure tone auditory stimulus of 2 kHz. Exposure of rats to the novel environmental stimuli for a period of 2 min decreased plasma concentrations of vasopressin and increased plasma levels of adrenocorticotrophic hormone (ACTH) and prolactin, but did not significantly change the plasma level of oxytocin. The stimuli, however, became ineffective for producing the suppressive vasopressin response as the period of exposure was prolonged to more than 5 and up to 30 min, although the prolonged stimuli were still effective for inducing facilitatory ACTH and prolactin responses. After repeated exposures of rats to the environmental stimuli once a day for 5 or 10 days, the stimuli became disabled from producing the suppressive vasopressin response. However, the rats were still capable of responding to the novel stimuli of another kind. All these data suggest that novelty stress suppresses vasopressin secretion but does not change oxytocin secretion. In order to test the possibility that glucocorticoids expectedly secreted by the adrenals in response to the stress might have suppressed vasopressin secretion, a large amount of dexamethasone was administered to the rat before testing. Dexamethasone pretreatment depressed plasma levels of ACTH and vasopressin as reported previously and blocked the facilitatory ACTH response to the novelty stress. However, dexamethasone treatment did not affect the suppressive vasopressin response to the novelty stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1993

Localizing value of seizure manifestations of temporal lobe epilepsies and the consequence of analyzing their sequential appearance.

We investigated the localizing and lateralizing value of principal seizure manifestations in temporal lobe epilepsies (signal symptoms, oroalimentary automatisms, somatomotor manifestations, unilateral dystonic posturing, ictal speech, motionless stare) of 223 complex partial seizures in 50 patients. All the patients had invasive long-term monitoring with the combined implantation of intracerebral electrodes in and subdural electrodes on the bilateral temporal lobes. Postoperative freedom from seizures was ascertained for longer than one year. We found that 35 patients had amygdalohippocampal seizures and 15 had lateral temporal seizures. The value of the manifestations was established in relation to the site and side of seizure origin and to the progression of seizure discharges within the unilateral temporal lobe or to the contralateral cerebral hemisphere. Several signs among the manifestations were found to be reliable in predicting the site or side of the temporal lobe seizure focus. We emphasized the importance of investigating sequential changes of seizure manifestations in relation to ictal EEG findings by means of simultaneous recording.

Amygdala↗
PubMed1993

Drop attacks and epileptic syndromes.

1. In addition to 4 types of drop attacks previously described by Ikeno et al., we could ascertain the falls of the myoclonic-tonic type in genuine drop attacks. The genuine drop attacks were seen in Lennox-Gastaut syndrome, epilepsy with myoclonic-astatic seizures and other symptomatic generalized epilepsies, and never in partial epilepsies. 2. None of the patients with partial epilepsy revealed genuine drop attacks as defined. Their drop attacks were slower (i.e. the falls were completed in more than 1 sec.). 3. In the 15 patients with Lennox-Gastaut syndrome, the drop attacks disappeared in 8 patients, and decreased in severity and frequency in 3 patients. Namely, the intractability of drop attacks in two-thirds of the children decreased as the patients grew older. This finding must be taken into consideration when patients with drop attacks are considered for surgical treatment of their epilepsy.

Adolescent↗
PubMed1993

Rapid formation of multicellular spheroids of adult rat hepatocytes by rotation culture and their immobilization within calcium alginate.

Tyrosine aminotransferase (TAT) induction and albumin secretion abilities were examined in rat hepatocytes immobilized within calcium alginate; the immobilized hepatocytes lost these abilities within a week. An attempt was then made to immobilize multicellular spheroids of hepatocytes for the purpose of stabilizing the liver functions. Although it takes at least 4 days to form spheroids in the conventional method using monolayer-cultured cells, in this study we developed a new method for rapid spheroid formation. Isolated hepatocytes were seeded into a polystyrene dish and incubated on a rotary shaker. Hepatocytes started to aggregate after 6 h of the rotation culture, and spheroids approximately 100 microns in diameter formed within 24 h. The immobilized spheroids had higher TAT induction and albumin secretion abilities, which were maintained for a longer time, than the immobilized nonaggregated cells. Further stabilization was observed in immobilized heterospheroids formed in the presence of nonparenchymal liver cells. This method for the rapid formation of spheroids consisting of hepatocytes and nonparenchymal liver cells could be utilized in the construction of a bioartificial liver support system.

Albumins↗
PubMed1993

Increase in T cells bearing the gamma/delta receptor associated with lymphoproliferative disease of granular lymphocytes in an infant with intractable diarrhea.

A two-year-old infant with intractable diarrhea and lymphoproliferative disease of granular lymphocytes attributed to a persistent cytomegalovirus infection showed an increase in cells bearing the gamma/delta T-cell receptor (TCR), which accounted for approximately 20% of total peripheral blood lymphocytes and 40% of CD3+ T cells. Of the gamma/delta TCR+ cells, two-thirds were double negative (CD4-/CD8-) and the other one-third CD8 positive. The majority of gamma/delta+ cells were delta TCS 1 positive. The predominance of delta TCS 1 positive cells was also confirmed on biopsy of lymphoid tissues from the colon. After improvement of watery diarrhea and malnutrition following three-month hyperalimentation, the number of gamma/delta TCR+ cells decreased. The patient subsequently died of pneumonia at the age of 2 years and 11 months. A possible site-specific role for the gamma/delta TCR+ cells, particularly delta TCS 1+ cells, in the human intestine is discussed.

Child, Preschool↗
PubMed1993

Characteristics and localization of a determinant conferring partial macrolide resistance in Staphylococcus aureus carrying plasmid.

Staphylococcus aureus TPR-27, a clinically isolated strain, showed constitutive resistance to some macrolide antibiotics (erythromycin, oleandomycin, spiramycin, and josamycin), but susceptibility to the other macrolide (tylosin, rokitamycin, and mycinamicin), lincosamide, and streptogramin type B antibiotics (PM-resistance). The PM-resistant strain TPR-27 has carried for visible plasmids. Attempts to eliminate the resistant determinant in terms of ethidium bromide (about 3 micrograms/ml) did not succeed, and every trial to transduce the PM-resistant determinant into rec- mutant ISP105 using phage 80L2 propagated on strain TPR-27 also failed at the frequency of less than 1.1 x 10(-10) transductants per plaque-forming unit. These results suggest that the PM-resistance determinant is localized in chromosomal DNA.

Anti-Bacterial Agents↗
PubMed1993

L-gulono-gamma-lactone oxidase is not induced in rats by xenobiotics stimulating L-ascorbic acid biosynthesis.

L-Ascorbic acid (AsA) is synthesized from D-glucose in rats; the terminal step of this synthetic pathway is catalyzed by L-gulono-gamma-lactone oxidase (GLO). In this study, we examined the effects of phenobarbital (PB) and 3-methylcholanthrene (MC), both of which are known to stimulate AsA biosynthesis in rats, on the hepatic levels of GLO activity, GLO mRNA, and AsA. Firstly, the existence of GLO mRNA was examined in the liver, kidney, lung, small intestine, spleen, testis, and prostate from a male rat; and GLO mRNA was found to be present only in the liver, in which GLO activity was also detected. The intraperitoneal injection with PB (100 mg/day/kg body weight, once a day for 2 days) or MC (20 mg/day/kg body weight, once) significantly elevated the hepatic level of AsA and the urinary excretion of AsA in rats (5-week-old males). The hepatic levels of cytochrome P-450IIB1 mRNA and cytochrome P-450IIB2 mRNA and those of cytochrome P-450IA1 mRNA and cytochrome P-450IA2 mRNA were also elevated in the rats treated with PB and MC, respectively, indicating a normal response of these animals to these compounds. However, the level of GLO mRNA and the activity of GLO in the liver tended to be slightly decreased by the administration of PB or MC, though the differences were not significant. Thus it is clear that the treatment with PB or MC stimulates the biosynthesis of AsA by increasing the activity of some enzyme(s) participating in the synthesis prior to GLO.

Animals↗
PubMed1993

[Postictal aphasia and its generating mechanism in 3 patients with localization-related epilepsy].

Semiology of postictal aphasia as well as its generating mechanism involving both the epileptogenic zone and language area has not yet been sufficiently elucidated. Therefore, postictal aphasias were studied in 3 patients with localization-related epilepsy. Postictal motor aphasia was observed in a patient (patient 1) with frontal lobe epilepsy whose recovery of language function progressed from loss of language function, to Broca's aphasia, and eventually to poor spontaneous speech. Postictal sensory aphasia was observed in 2 patients (patient 2 and 3) with temporal lobe epilepsy whose recovery of language function progressed from loss of language function, to jargon, and eventually to circumlocutory anomic speech. Both patient 2 and 3 did not show fluent speech. Seizure manifestations, EEG, IMP-SPECT and MRI indicated that epileptogenic zones were in the left frontal lobe including Broca's area in patient 1, the mesial part of the left temporal lobe in patient 2, and the middle and posterior part of the left temporal lobe including Wernicke's area in patient 3. A postictal verbal dichotic listening test showed the reduction of correct responses by right ear in the patient 3. Postictal auditory verbal learning tests showed the impairment of verbal memorization in patient 2 and 3. The impairment of verbal memorization was particularly marked in patient 2. These results suggest that 1) the characteristics of postictal motor and sensory aphasia are clearly elucidated by analyzing the sequence of recovery from postictal language dysfunction, 2) postictal aphasia is generated by the epileptogenic zone involving the language area or the ictal discharges propagating to the language area, and 3) not only the disturbance of language function, but also the impairment of verbal memorization seems to participate in the disturbance of repeating and understanding sentences in the patient with postictal sensory aphasia.

Adult↗
PubMed1993

[Present world status and problems resolved in lung transplantation: from the surgical view].

We have summarized the results of international data from many institutes. In 1983 in Toronto, Canada, Cooper performed that first successful clinical case lung-transplantation. Subsequently, there have been more than 1,500 cases of lung transplantation. One reason for Cooper's success was the use of cyclosporin, the other was the performing of omentopexy. Among the total lung transplant cases, single lung transplant comprised 66%, bilateral sequential lung transplant comprised 26%, and en-blocdouble lung-transplant, (8%). Of the 1,540 recipients, the most common underlying of sease was emphysema (360 cases), followed by fibrosis (289 cases), cystic fibrosis (206 cases), alpha-1 antitripsin deficiency (210 cases) and rare diseases including pulmonary hypertension, lymphagiomyomatosis and sarcoidosis. The survival rate of all patients was 68% at 1 year, and 60% at two years.

Adolescent↗
PubMed1993

Sequential deletion of DNA by use of remodeled pUC18 and pUC19 vectors.

pUC18 and pUC19 vectors were remodeled by replacement of their EcoO109I-NdeI portion with a "buffer sequence" of approximately 2.3 kilobase pairs derived from human genomic DNA. By use of the resulting plasmids, one can delete a target DNA that has been inserted into the polycloning site, deleting the buffer sequence at the same time, after linearization with an appropriate restriction enzyme that cleaves at the polycloning site. After the undeleted portion of the buffer sequence is cleaved off at the unique EcoRV site existing at its end, the plasmid can be recircularized for nucleotide sequencing from the deleted end of the target DNA. Thus the remodeled vectors enable deletion of DNAs by this simple method.

Base Sequence↗
PubMed1993

Immunological differentiation between novel monomeric and classic tetrameric rat liver glutathione peroxidases.

Difference between a novel monomeric enzyme and the classic tetrameric enzyme of glutathione peroxidase in rat liver was examined immunologically. The polyclonal antibody raised against the novel enzyme reacted with the novel enzyme, but not with the classic enzyme. Likewise the anti-classic enzyme antibody reacted with the classic enzyme, but not with the novel one. The activity of the novel enzyme was decreased by the treatment with the anti-novel enzyme antibody, but not with the anti-classic enzyme antibody, and vice versa for the classic enzyme. Thus the novel monomeric glutathione peroxidase is a protein immunologically distinct from the classic enzyme.

Animals↗
PubMed1993

[Long-term follow-up of a case of Landau-Kleffner syndrome].

Long-term investigation of a male case of Landau-Kleffner syndrome with auditory, verbal and non-verbal agnosia was performed clinico-electroencephalographically and neuropsychologically. Atypical absences and secondarily generalized tonic-clonic seizures were observed. The spike-wave index of slow wave sleep from all-night EEG recordings was 96% in this case. It was impossible to differentiate this case from epilepsy with "continuous spikes and waves during slow wave sleep (CSWS)" except the presence of auditory agnosia. Auditory agnosia of this case disappeared after antiepileptic therapy. It is suggested that Landau-Kleffner syndrome showing CSWS may have a good prognosis about agnosia from that of this case and others previously reported.

Agnosia↗
PubMed1993

Immunohistochemical localization of paraquat in skin and eye of rat.

Immunohistochemical techniques were used to observe the localization of paraquat in the skin and eyes of rats. Paraquat poisoned rats were killed 3 h, 12 h, 24 h, 3 days, 7 days and 10 days after intravenous administration of paraquat. In skin, paraquat was localized in the ducts of sweat glands and sebaceous glands between 3 and 10 days after paraquat injection. In eyes, weak positive findings were observed in nerve fibers of retina between 3 and 10 days after the injection. In cornea, paraquat was localized in epithelial cells at the first 3 h and between 3 and 10 days after paraquat administration. Since skin occupies a vast area of the body in animals, as an organ, it seems to be an important storage pool for the redistribution of paraquat.

Animals↗
PubMed1993

Surgical management of toxic goitre in Khartoum.

Seventy patients with toxic goitre treated surgically in two surgical firms in Khartoum during a 10-years period were studied. Of these patients 62.9% had diffuse goitres, 34.3% nodular and 2.8% hot clinically solitary nodules. The age ranged between 15 and 54 years and the M:F ratio was 1.0:6.7. Ninety per cent of the patients had large size goitres (grade III). Preoperative carbimazole and inderal were found to be superior to other drug combinations. Subtotal thyroidectomy was the standard procedure and no serious postoperative complications were noted. Fifteen patients had postoperative hectic period i.e. fever, headache and tachycardia that responded to temporary inderal and steroids. Surgical treatment of toxic goitre in developing countries could be extended to include more patients since drug availability and patient compliance are minimal.

Adolescent↗