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Biomedical subjects

K Yagi

Publications and source records attributed to K Yagi.

At least 109 records · Page 6Linked to original sources
PubMed2000

Microvascular ischemia in patients with myotonic dystrophy.

Two women with myotonic dystrophy underwent dipyridamole thallium-201 (201Tl) myocardial perfusion imaging, after which one patient developed flat T waves in lead I and aV(L), and inverted T waves in leads V(2-6). The other patient developed a nonspecific intraventricular block that progressed to complete left bundle branch block and was associated with chest discomfort. Reversible scintigraphic defects were observed in both women. Although there was evidence that suggested myocardial ischemia on the ECG changes and 201Tl scintigraphic findings, coronary angiography demonstrated no significant stenoses in either patient. These findings suggest that microvascular dysfunction may lead to myocardial ischemia and conduction disturbances in patients with myotonic dystrophy.

Electrocardiography↗
PubMed2000

Potent inhibition of macrophomate synthase by reaction intermediate analogs.

Potent inhibitors for macrophomate synthase, which has recently been found to catalyze a highly unusual five-step chemical transformation, were explored. Among 11 oxalacetate analogs tested, only three analogs had moderate to relatively strong inhibitory activities (I50 1.3-8.1 mM). On the other hand, among 35 bicyclic intermediate analogs synthesized, two diacids were found to be the most potent inhibitors (I50 0.80, 0.84 mM) which had a much higher affinity than that of the natural substrate 2-pyrone. (-)-Enantiomers of the diacids showed 30 times stronger activity (I50 0.34, 0.41 mM) than (+)-ones. The I50/Km values (0.20, 0.24) showed their potent inhibitions. Competitive inhibitions were observed in two representative inhibitors.

Binding, Competitive↗
PubMed2000

[Dyslipidemia in insulin resistance and its improvement by troglitazone].

Dyslipideia in insulin resistant state are characterized by 3 major components; increased triglyceride levels, decreased high-density lipoprotein (HDL) cholesterol, and change in the composition of low-density lipoprotein (LDL) cholesterol particle which results in small-dense LDL. Insulin resistance is thought to lead to overproduction of very low-density lipoprotein (VLDL) cholesterol through the decreased peripheral lipoprotein lipase (LPL) activity, increased production of apolipoprotein B-100 and decreased clearance of remnant particles. Troglitazone, an insulin action enhancer, decreases the triglyceride level, increases HDL cholesterol level and decreases th proportion of small-dense LDL through the direct effect on lipoprotein metabolism. However, activation of PPAR-gamma is considered to possese potential atherogeneity and more closer examination is needed.

Cholesterol, HDL↗
PubMed2000

[Prophylaxis with FK-506 for graft-versus-host disease after transplantation of bone marrow from unrelated donors].

Forty-eight patients who underwent bone marrow transplantation (BMT) from serologically HLA-matched unrelated donors received tacrolimus (FK506) alone or with methotrexate (MTX) and/or methylprednisolone (mPSL) to prevent graft-versus-host disease (GVHD). We analyzed retrospectively the efficacy of FK506 for GVHD prophylaxis, and its toxicity, by comparing three groups of patients: those given FK506 alone, those given FK506 + mPSL, and those given FK506 + MTX + mPSL. Grade III and IV acute GVHD occurred in five of 10 patients given FK506 alone and in 11 of 30 patients given FK506 + mPSL. In these groups, severe acute GVHD was commonly seen in the patients who discontinued FK506 administration early after BMT and in those who received bone marrow from genotypically HLA-mismatched donors. Early withdrawal of FK506 was due mainly to severe nephrotoxicity. The incidence of nephrotoxicity was very high in patients who received high-dose FK506 as well as melphalan-containing preconditioning (80% and 50%). None of eight patients who received FK506 + mPSL + MTX developed grade III-IV acute GVHD even though five of them received bone marrow from genotypically HLA-mismatched donors. In patients receiving bone marrow from unrelated donors, adjustment of the initial dose of FK506 seems essential in order to avoid severe nephrotoxicity, and combination of MTX and FK506 is useful for preventing severe acute GVHD.

Adolescent↗
PubMed2000

[Anesthetic management for reconstruction of the superior vena cava by monitoring of peripheral venous pressure in a patient with a mediastinum tumor].

A 26-years-old man with a giant mediastinum tumor was scheduled for reconstruction of the superior vena cave and tumor resection. Anesthetic management for reconstruction of the superior vena cava was performed by monitoring of peripheral venous pressure. A bypass between the inominate vein and right auricula was made by using an artificial vessel before clamping the superior vena cava. When the superior vena cava was clamped, peripheral venous pressure increased suddenly to 42 mmHg. Immediately after the venesection from the peripheral vessel, it was possible to control peripheral venous pressure at about 20 mmHg. Blood was re-transfused from the femoral vein to the patient. Cerebral neurological symptom due to the increasing venous pressure was not detected. In conclusion, monitoring peripheral venous pressure during reconstruction of the superior vena cava in a patient with a mediastinum tumor may be a useful technique.

Adult↗
PubMed2000

Prognostic factors in childhood acute lymphoblastic leukemia in Japan. Japan Association of Childhood Leukemia Study.

A retrospective analysis of children with acute lymphoblastic leukemia (ALL) was performed to evaluate the current status of diagnosis and treatment of ALL in Japanese children. Clinical records of 670 children with ALL were collected and analyzed; these children had been diagnosed between 1991 and 1995 at the 53 institutions in 4 areas participating in the Japan Association of Childhood Leukemia Study. It was found that T-cell ALL was significantly less frequent in Tokai and Hokkaido than in Kansai and Chu-Shikoku. The overall induction rate was 92.4%. The estimated 7-year overall survival rate and event-free survival (EFS) rate were 76.0% +/- 1.9% and 61.4% +/- 2.1%, respectively. EFS rates were significantly different among the geographic areas. In female patients with B-cell precursor (B-pre) ALL and white blood cell counts at diagnosis (WBCsdiag) below 50.0 x 10(9)/L, favorable outcomes were significant. Favorable outcomes were not significant in B-pre ALL patients with a WBCdiag above 50.0 x 10(9)/L or in T-cell ALL patients. The EFS rate for infants was significantly worse than that for patients over 1 year of age. In B-pre ALL, but not in T-cell ALL, it was found that the higher the WBCdiag, the worse the EFS rate. Multivariate analysis showed that the following factors were significantly unfavorable for EFS: the Philadelphia chromosome, an translocations associated with chromosome 11q23, an acute unclassified leukemia, mixed-lineage leukemia, a WBCdiag above 100.0 x 10(9)/L, and male gender. Hyperdiploidy (> 50 chromosomes) was significantly favorable for EFS. For further tailoring of treatment and to improve the outcome in childhood ALL, a prospective large-scale study should be undertaken in Japan.

Age Factors↗
PubMed2000

Anti-apoptotic function of L-(-)deprenyl (Selegiline) and related compounds.

(-)Deprenyl has been proposed to be neuroprotective to dopamine neurons in the parkinsonian brains. To clarify the mechanism, the effects of (-)deprenyl and structurally related compounds on apoptosis induced by a neurotoxin, N-methyl(R)-salsolinol, and reactive oxygen species, nitric oxide and peroxynitrite, were examined in dopaminergic SH-SY5Y cells. DNA damage was quantified by the single cell gel electrophoresis (comet) assay. (-)-Deprenyl protected the cells from apoptosis in a dose-dependent way, which required pre-treatment at least for 20 min. The effect was confirmed even after washing out of (-)deprenyl, indicating that (-)-deprenyl initiates the intracellular process to antagonize the apoptotic death program. The studies on the structure-activity relationship reveal that N-propargyl residue with hydrophobic structure is essential for the anti-apoptotic function. These results suggest that (-)deprenyl and related compounds may be applicable as neuroprotective agents in neurodegenerative diseases.

Antioxidants↗
PubMed2000

[Recent advance in epileptology].

Nowadays epilepsy is classified according to the international classification of epilepsies, epileptic syndromes and related disorders proposed by International League Against Epilepsy (ILAE, 1989). Among these epilepsies and epileptic syndromes, I detailed the clinical symptomatology and the clinical significance of benign familial neonatal convulsions, juvenile myoclonic epilepsy, epilepsy with myoclonic absence, mesial temporal lobe epilepsy and chronic progressive epilepsia partialis continua of childhood. Of 218 patients with temporal lobe resection who were followed for over 2 years, 172 patients or 79% were seizure free according to Engel's criteria of seizure outcome after surgical treatment. Of 66 patients with extra-temporal lobe epilepsy, 43 patients or 65% were seizure free. From the postsurgical outcome I talked about the need of strict presurgical evaluation to have the good postsurgical outcome. The neuropathology of surgically resected 278 specimens of temporal lobe epilepsy was mesial temporal sclerosis in 184, neuroepithelial tumors in 66, cortical malformation in 11, vascular anomaly in 13, and others in 4. Thirty-nine of resected 66 specimens of extra-temporal lobe epilepsies were cortical malformation. I presented the recent progress of genetic study in epilepsies and stressed the importance of correct diagnosis of epilepsy for genetic study.

Brain↗
PubMed1999

Loss of molecular interaction between cytochrome c and cardiolipin due to lipid peroxidation.

To explore the molecular mechanism underlying the translocation of cytochrome c from the mitochondrial inner membrane to the cytosol during apoptosis, we analyzed the molecular interaction between cytochrome c and cardiolipin (CL) by (1)H NMR spectroscopy. Bovine heart CL induced a drastic broadening of the linewidth of the downfield signals at 31.4 and 34.2 ppm assigned to the heme methyl group-3 and -8, respectively, of horse heart cytochrome c. In contrast, CL mono- and dihydroperoxides were less active in broadening the signals than CL, and CL trihydroperoxides induced almost no broadening of their linewidth. This finding suggests that the peroxidation of CL induces a release of cytochrome c from mitochondria into the cytosol, which release induces apoptosis in the cells.

Animals↗
PubMed1999

Photosensitive epilepsies and pathophysiologic mechanisms of the photoparoxysmal response.

OBJECTIVE: To identify the pathophysiologic mechanisms of the photoparoxysmal response (PPR) in various photosensitive epilepsy syndromes, and to discuss the relation between these pathophysiologic mechanisms and the classification of epilepsies and epileptic syndromes. BACKGROUND: The authors found two types of pathophysiologic mechanisms of PPRs (wavelength-dependent PPRs and quantity-of-light-dependent PPRs) in patients with idiopathic generalized epilepsy and hereditary dentatorubral-pallidoluysian atrophy. METHODS: Intermittent photic stimulation with wavelength-specific optical filters was performed in photosensitive epileptic patients: six patients had severe myoclonic epilepsy in infancy (SMEI), eight had localization-related epilepsy (LRE), and seven had symptomatic generalized epilepsy (SGE). RESULTS: Four of the six photosensitive SMEI patients had quantity-of-light-dependent PPRs. Five of the eight photosensitive LRE patients had wavelength-dependent PPRs. Four of the seven photosensitive SGE patients had wavelength-dependent PPRs, and two had quantity-of-light-dependent PPRs. CONCLUSIONS: The type of pathophysiologic mechanism for eliciting PPRs by low-luminance photic stimulation was closely related to the classification of the epilepsy syndrome.

Adolescent↗
PubMed1999

Dopamine-selective response in membrane potential by homooxacalix[3]arene triether host incorporated in PVC liquid membrane.

Selectivities of membrane potential changes for catecholamines and inorganic cations were investigated with lipophilic derivatives of calix[6]arene and related hosts incorporated in poly(vinyl chloride) (PVC) matrix liquid membranes. Homooxacalix[3]arene triether displayed an excellent selectivity for dopamine against other catecholamines (adrenaline, noradrenaline) and also against inorganic cations (K+, Na+).

Dopamine↗
PubMed1999

Basic study on gene therapy of human malignant glioma by use of the cationic multilamellar liposome-entrapped human interferon beta gene.

For gene therapy of human malignant glioma, we adopted positively charged multilamellar liposomes entrapping the human interferon beta (hIFN-beta) gene. One week after the transplantation of human malignant glioma U251-SP cells to produce glioma in nude mouse brain, the liposomes entrapping the gene (500 ng of DNA per 25 nmol of lipids per 2 microl) were injected into the same site of the cell transplantation once every second day for a total of five injections; and by this means the tumor completely disappeared. To confirm the antiproliferative effect of hIFN-beta, we performed an in vitro study using a plasmid containing a secretion signal sequence-deleted hIFN-beta gene and one containing the hIFN-beta gene inserted in reverse. In both cases, there was no hIFN-beta release into the medium and no growth inhibition effect. On addition of anti-hIFN-beta antibody to the medium, the growth inhibition effect was abolished. As this cell line expresses IFN-alpha/beta receptor, the hIFN-beta produced in the transfected cells could be released and acted in a paracrine manner. For 120 days the body weight change of normal mice treated by the same procedure as used in the curing experiment was not significant among the groups injected with empty liposomes, plasmid only, and liposomes entrapping the gene. In all of these three groups, death, abnormal behavior, and significant histological changes were not observed.

Animals↗