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Biomedical subjects

S Okada

Publications and source records attributed to S Okada.

At least 343 records · Page 19Linked to original sources
PubMed1998

Distribution of zinc in the substantia nigra of rats treated with 6-hydroxydopamine.

To study the relationship between tissue accumulation of Zinc (Zn) and neurodegeneration in the nigrostriatal dopaminergic pathway, 65Zn distribution in this pathway was examined after unilateral injection of 6-hydroxydopamine (6-OHDA) into the substantia nigra of rats. When 65ZnCl2 was intravenously injected 4 days after treatment with 6-OHDA, 65Zn was concentrated in the ipsilateral substantia nigra 6 days after 65Zn injection. On the other hand, 19 d after treatment with 6-OHDA, 65Zn distribution in the ipsilateral substantia nigra was decreased to the level of the contralateral one. When NH4(99)TcO4, which cannot go through the blood-brain barrier, was injected into rats 4 d after treatment with 6-OHDA, 99Tc was concentrated in the ipsilateral substantia nigra 30 min after 99Tc injection, but no longer detectable 6 d after injection. These results suggest that Zn is necessary for a repair process called replacement gliosis after the death of neurons and that excess Zn does not accumulate in the lesion after completion of the gliosis.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1998

Emergent bronchofiberoptic bronchial occlusion for intractable pneumothorax with severe emphysema.

Emergent bronchofiberoptic bronchial occlusion using fibrin glue and woven polyglycolic acid mesh for persistent pneumothorax with severe emphysema is described. A 74-year-old man who had severe pulmonary dysfunction accompanying chronic emphysema was admitted with a complaint of sudden severe dyspnea. The chest X-ray on admission revealed collapse of the right lung. The patient was placed on a mechanical ventilator because of acute respiratory failure. In spite of continuous suction through a chest drainage tube, air leakage persisted. On the seventh hospital day, subcutaneous emphysema was apparent in the face and scrotum in addition to the chest. First, a double-lumen catheter was inserted into the right B5 bronchus, and fibrin glue was infused into the drainage bronchus via the double-lumen catheter. However, the procedure failed. Next, a combination of fibrin glue and woven polyglycolic acid mesh which had been cut into small pieces was introduced and pushed into the B5 bronchus using forceps. The air leakage stopped immediately after the administration. This procedure is simple and a minimally invasive method for the treatment of intractable pneumothorax in a compromised patient on a mechanical ventilator.

Aged↗
PubMed1998

Characteristic MR features of encephalitis caused by Epstein-Barr virus: a case report.

An 8-year-old girl showed symptoms of encephalitis during acute Epstein-Barr virus (EBV) infection. The diagnosis of EB virus infection was made by changes in the titres of EB virus-specific antibody. Cranial MRI demonstrated abnormal low and high signal intensities in the striatal body (putamen and caudate nucleus) on T1-weighted and T2-weighted images, respectively, during the acute phase. These abnormal findings had almost completely resolved 1 month later. EBV infection should be considered when lesions are localised to the basal ganglia.

Caudate Nucleus↗
PubMed1998

Disseminated intravascular coagulation in acute lymphoblastic leukemia at presentation and in early phase of remission induction therapy.

A high frequency of disseminated intravascular coagulation (DIC) in adult acute lymphoblastic leukemia (ALL) has been reported; however, its clinical relevance and characteristics have not been fully determined. We studied 67 adults with newly diagnosed ALL between 1982 and 1996 to clarify these questions. DIC was diagnosed in ten of 64 patients (16%) who underwent coagulation study at presentation and in 14 of 40 patients (35%) screened for DIC within 7 days after starting remission induction therapy. Overall, 24 of 67 patients (36%) had DIC during this period. Hemorrhagic symptoms were generally mild, while two patients required red blood cell transfusions. Patients who developed DIC had higher white blood cell counts and more frequently a palpable spleen than those who did not. There was no difference in age, French-American-British subtype, karyotype, immunophenotype, lactate dehydrogenase level, percentage of blasts in bone marrow, or frequency of lymphadenopathy or hepatomegaly between patients who had DIC and those who did not. Fibrinolysis tended to be milder in DIC complicating ALL than in that complicating acute promyelocytic leukemia; however, there was no difference in other coagulation parameters between these two subtypes. An etiological link between CD34 expression in common ALL patients and DIC was suggested.

Adolescent↗
PubMed1998

Intranuclear iron deposition in hepatocytes and renal tubular cells in mice treated with ferric nitrilotriacetate.

Cytoplasmic and intranuclear iron depositions were observed in the livers and kidneys of male and female ddY mice treated for 4-12 weeks with ferric nitrilotriacetate (Fe-NTA), a known renal carcinogen that acts through the production of free radicals. The intranuclear iron deposition consisted of a spherical aggregation of ferritin particles of approximately 10 nm diameter, as revealed by immunohistochemical staining and electron microscopy. Although the incidence of renal tumours was greater in the males than in the females, the incidence of iron depositions did not differ with gender. The most abundant intranuclear iron depositions were observed in the animals treated with Fe-NTA for the longest duration (12 weeks). These findings suggest that the intranuclear production and propagation of free radical reactions are prevented by the trapping of iron in a chemically inert iron form of ferritin.

Animals↗
PubMed1998

Molecular cloning of the chromosomal breakpoint in the LIS1 gene of a patient with isolated lissencephaly and balanced t(8;17).

Karyotypic analysis of a patient exhibiting a phenotype of isolated lissencephaly, and of her parents, revealed a de novo balanced translocation, t(8;17)(p11.2; p13.3). Since the lissencephaly (LIS1) gene was known to be located on 17p13.3, we investigated whether the translocation might involve this gene. We performed Southern analysis using cosmid clones that contained genomic sequences corresponding to LIS1, and found that the breakpoint was located within intron 1. As sequence analysis of the parental chromosomes in the vicinity of the breakpoint identified no additional putative transcripts, haploinsufficiency of the LIS1 gene is likely to be solely responsible for the patient's lissencephaly. Characterization of both breakpoints indicated a possible involvement of repetitive sequences in the recombigenic process that led to the translocation.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1998

Genomic organization and mutational analysis of KVLQT1, a gene responsible for familial long QT syndrome.

To elucidate the role of the KVLQT1 gene in the pathogenesis of long QT syndrome (LQTS), we have established a screening system for detecting KVLQT1 mutations by the polymerase chain reaction-single strand conformation polymorphism technique (PCR-SSCP). We first determined exon/intron boundaries and flanking intronic sequences, and found that the KVLQT1 gene consists of 17 coding exons. Subsequently, we synthesized oligonucleotide primers to cover the coding region and the flanking intronic sequences, and searched for mutations in 31 Japanese LQTS families. When genomic DNA from each proband was examined by PCR-SSCP followed by direct DNA sequencing, mutations were detected in five families; two independent families carried the same mutation and three of the four were novel. Each mutation was present in affected relatives of the respective proband. This work will enable us to search more thoroughly for LQTS mutations associated with KVLQT1, and eventually will help us in finding genotype/phenotype relationships.

DNA Mutational Analysis↗
PubMed1998

Alteration of the LIS1 gene in Japanese patients with isolated lissencephaly sequence or Miller-Dieker syndrome.

LIS1 is a genetic entity that is responsible for lissencephaly. Previously we have reported isolated lissencephaly sequence (ILS) in a Japanese patient carrying a balanced chromosomal translocation that disrupted the LIS1 gene. We examined mutations of LIS1 in 12 additional Japanese patients, 8 of them with ILS and 4 with Miller-Dieker syndrome (MDS). Fluorescence in situ hybridization (FISH) analysis disclosed deletions of part of the LIS1 gene or of the chromosomal region surrounding it in three of the ILS cases and in three of the MDS cases. In one of the remaining five ILS cases, SSCP analysis and subsequent sequence analysis identified a 1-bp deletion in exon IV, which can be expected to result in premature termination of the gene product. Our results indicate that in Japan, as elsewhere, abnormality of the LIS1 gene is a common cause of MDS/ILS.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1998

Modified hepatoduodenal ligamentectomy for advanced carcinoma of the biliary tract: the importance of preservation of the replaced left hepatic artery.

Hepatoduodenal ligamentectomy (ligamentectomy) is the ultimate surgery for biliary tract carcinoma involving perioperative difficulties such as total hepatic ischemia during revascularization of the hepatic artery and the portal vein, patency of the reconstructed hepatic artery, and high incidence of related operative mortality. In the present study, modified ligamentectomies with extended right hepatic lobectomy, including resection of the caudate lobe, were performed on three patients with advanced biliary tract carcinoma in whom the left hepatic artery had been replaced and the original artery was preserved. In all patients, postoperative courses were uneventful: success of the resection was confirmed by histological examination. This procedure enabled en bloc resection of hepatoduodenal ligament with positive cancer invasion to take place. It was carried out safely without concern for the difficulties described above. In our view, ligamentectomy should be performed in all such cases.

Aged↗
PubMed1998

Treatment of recurrent hepatocellular carcinoma by hepatectomy with right and middle hepatic vein reconstruction using total vascular exclusion with extracorporeal bypass and hypothermic hepatic perfusion: report of a case.

We report herein the case of a patient who had previously undergone a lateral segmentectomy for hepatocellular carcinoma (HCC) in whom recurrent HCC invading the trunk of the right and middle hepatic veins in a damaged liver was treated by reconstruction of both hepatic veins, using total vascular exclusion with extracorporeal bypass and hypothermic hepatic perfusion. Reconstruction was performed using a graft taken from the left external iliac vein and divided into two pieces. Hepatic ischemia lasted for 91 min during the procedure and the intrahepatic temperature, as monitored by inserting a needle-type thermometer, was decreased to 11 degrees C throughout the procedure. The peak levels of serum glutamic pyruvic transaminase, lactate dehydrogenase, and total bilirubin were 363 IU/l, 1198 IU/ml, and 2.8 mg/dl, respectively, on postoperative day (POD) 2. The patient's postoperative course was uneventful except for mild, temporary swelling of the left leg. Postoperative computed tomography and magnetic resonance imaging examinations disclosed no obstruction of either graft, and the patient was discharged on POD 40.

Carcinoma, Hepatocellular↗
PubMed1998

Favorable response to lymphoblastoid interferon-alpha in children with chronic hepatitis C.

BACKGROUND/AIMS: We investigated the efficacy of interferon therapy for the treatment of children with chronic hepatitis C virus infection. METHODS: Twenty-four out of 26 children completed the 6-month treatment with lymphoblastoid interferon-alpha and were followed for 12 months or longer. Response to interferon therapy was defined by assaying for circulating HCV-RNA, using a nested PCR, at 6-month intervals after the end of the therapy. RESULTS: At the end of treatment circulating HCV-RNA was undetectable in 18/24 patients and at 6 months in 12/24. Ten of these 12 primary responders have remained virus free for more than 2 years. One patient remained negative at 12 months. The remaining patient relapsed at 12 months. At 24 months 10 of 18 patients tested negative for HCV-RNA. Serum alanine aminotransferase was normal in 11/24 patients at the end of treatment, at 6 months 12/24 were normal, and at 12 months 11/12 were normal. In eight children with sustained response, repeated liver biopsies revealed a reduction in Knodell's scores for inflammation in the hepatic lobules and in the portal areas. In three of them neither plus nor minus strand of HCV-RNA was detectable in the liver tissue. Responders had a significantly lower level of viremia than non-responders. Side effects of interferon including fever, hair loss, neutropenia, and thrombocytopenia were not serious enough to warrant cessation of interferon treatment. CONCLUSIONS: Interferon therapy in children with chronic hepatitis C may be beneficial as evaluated by sustained loss of viremia as well as by primary response.

Adolescent↗
PubMed1998

The repetitive activation of extracellular signal-regulated kinase is required for renal regeneration in rat.

In this study, we investigated the activation of p42 extracellular signal-regulated kinase (ERK2) during renal regeneration after HgCl2-induced acute renal failure (ARF) in rat. ERK2 activation was observed at 5 and 29 hr after HgCl2 injection, respectively. The tyrosine phosphorylation of hepatocyte growth factor receptor (c-MET) occurred between 2.5 and 5 hr after the treatment. On the other hand, the phosphorylation of epidermal growth factor receptor (EGFR) was transiently observed at 29 hr after the injection. The peak of ornithine decarboxylase activity as a marker of G1 phase was at 10 hr, and subsequently the labeling index of proliferating cell nuclear antigen as a marker of S phase increased at 53 hr. These results indicate that the repetitive activation of ERK2 related to the phosphorylation of c-MET and EGFR is required for the renal regeneration in HgCl2-induced ARF of rat.

Acute Kidney Injury↗
PubMed1998

Genetic subtyping and epidemiological study of feline immunodeficiency virus by nested polymerase chain reaction-restriction fragment length polymorphism analysis of the gag gene.

Genetic subtyping of feline immunodeficiency virus (FIV) was carried out by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. A 329-base pair fragment in the FIV gag gene was amplified by nested PCR, then digested with restriction enzymes, HindIII, PvuII and BamHI. Using these restriction enzymes, FIV isolates belonging to subtypes A, B and D, which had been classified on the basis of the env gene V3-V5 sequence, could be discriminated. Genetic subtypes of FIV prevalent in Japan were investigated using the gag-nested PCR-RFLP analysis. Of 88 FIV-infected cats, PCR products of 70 cats showed a subtype B RFLP pattern (digestion only with PvuII), those of nine cats had a subtype D RFLP pattern (digestion only with BamHI), and those of seven cats had a subtype A RFLP pattern (digestion only with HindIII). The PCR products of the remaining two cats had subtype A and B RFLP patterns (digestion with both HindIII and PvuII). The digestion pattern of the gag-nested PCR-RFLP analysis was unchanged after in vivo passages of the virus. These results suggest that the gag-nested PCR-RFLP analysis is useful as a simple method for FIV genetic subtyping.

Animals↗
PubMed1998

Manganese transport in the neural circuit of rat CNS.

To study manganese (Mn) transport in the neural circuit of rat CNS, brain isotope distribution after 54Mn injection into the brain was analyzed by autoradiography. One day after 54MnCl2 injection into the striatum, 54Mn was highly distributed in the ipsilateral thalamus, hypothalamus, and substantia nigra. When 54MnCl2 was bilaterally injected into the striata after unilateral treatment with colchicine or vehicle into the medial forebrain bundle, 54Mn was distributed in both sides of the substantia nigra of vehicle-treated rats. On the other hand, unilateral colchicine treatment caused a decrease of 54Mn distribution in the ipsilateral substantia nigra, suggesting that Mn is subjected to axonal transport in the striatonigra and/or nigrostriatal pathways. In the case of unilateral injection of 54MnCl2 into the olfactory bulb, 54Mn was distributed in the ipsilateral piriform, amygdaloid areas (the primary olfactory cortex), and entorhinal area (the secondary olfactory cortex). These results suggest that Mn is subject to widespread axonal transport in the neural circuits. Moreover, Mn may be taken up by the piriform neurons (the third olfactory neuron) after release from the secondary olfactory neuron terminals and transported to the entorhinal area.

Animals↗