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Biomedical subjects

M Nonaka

Publications and source records attributed to M Nonaka.

At least 163 records · Page 9Linked to original sources
PubMed1996

Fourth component of Xenopus laevis complement: cDNA cloning and linkage analysis of the frog MHC.

Complement C4 shows extensive structural and functional similarity to complement C3, hence these components are believed to have originated by gene duplication from a common ancestor. Although to date C3 cDNA clones have been isolated from all major classes of extant vertebrates including Xenopus, C4 cDNA clones have been isolated from mammalian species only. We describe here the molecular cloning and structural analysis of Xenopus C4 cDNA. The cDNA sequence encoding the thioester region of Xenopus C4 was amplified by reverse transcriptase-polymerase chain reaction using Xenopus liver mRNA as a template, and then used to screen a liver cDNA library. The amino acid sequence of Xenopus C4 deduced from a clone containing the entire protein-coding sequence showed 39%, 30%, 25%, and 20% overall identity with those of human C4, C3, C5, and alpha2-macroglobulin, respectively. The predicted amino acid sequence consisted of a 22-residue putative signal peptide, a 634-residue beta chain, a 732-residue alpha chain, and a 287-residue gamma chain. Of 30 cysteine residues, 27 were found in exactly the same positions as in human C4. Genomic Southern blotting analysis indicated that C4 is a single copy gene in Xenopus and is part of the frog MHC cluster. These results clearly demonstrate that C3/C4 gene duplication and linkage between the C4 gene and the major histocompatibility complex predate mammalian/amphibian divergence.

Amino Acid Sequence↗
PubMed1996

Molecular cloning and linkage analysis of the Japanese medaka fish complement Bf/C2 gene.

Evolutionary studies of complement factor B (Bf) and C2 in lower vertebrates have revealed the presence of the Bf/C2 common ancestor-like molecule in lamprey (cyclostome) and the Bf molecule encoded by the duplicated genes closely linked to the major histocompatibility complex (MHC) in Xenopus (amphibian). To further define when Bf/C2 gene duplication occurred and when linkage between the Bf/C2 gene and the MHC was established, we amplified the Bf/C2 sequences in teleost, the Japanese medaka (Oryzias latipes), by reverse transcription - polymerase chain reaction with primers corresponding to the common amino acid sequences shared by mammalian Bf and C2. Only a single molecular species has been amplified, and the corresponding cDNA clones were isolated from the liver cDNA library. The longest insert contained 2384 nucleotides with an open reading frame of 754 residues. The deduced amino acid sequence showed 33.6% and 34.1% overall identity with the human Bf and C2 sequences, respectively, hence this clone was named medaka Bf/C2. The single-copy medaka Bf/C2 gene had exactly the same exon-intron organization as the mammalian Bf and C2 genes, and spanned about 8 kilobases. The Bf/C2 locus was mapped to the close proximity (2.9 cM) of the superoxide dismutase locus on the linkage group XX by the use of a restriction site polymorphism between two inbred strains of the medaka.

Amino Acid Sequence↗
PubMed1996

GM-CSF, IL-8, IL-1R, TNF-alpha R, and HLA-DR in nasal epithelial cells in allergic rhinitis.

Epithelial cells potentially contribute to airways inflammation by antigen presentation and the production of proinflammatory cytokines. This study investigated the immunocytochemical localization of interleukin-8 (IL-8), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 receptor (IL-1R Type I), tumor necrosis factor-alpha receptor (TNF-alpha R; 55kD), and human leukocyte antigen-DR (HLA-DR) on epithelial cells obtained by nasal brushing from 10 patients with allergic rhinitis in season and 15 healthy, nonallergic subjects. Six of the 15 nonallergic asymptomatic subjects had macroscopic evidence of nasal mucosal inflammation, and their brushings contained more than 10% neutrophils ("subclinical inflammation"). In normal control subjects, 8 +/- 7.5% of epithelial cells stained for HLA-DR, approximately one quarter stained for IL-8 and GM-CSF, and about one third stained positive for IL-1R and TNF-alpha R. The findings in subjects with allergic rhinitis in season and with subclinical neutrophilia were similar, and the numbers of cells staining for HLA-DR expression correlated with both neutrophil and lymphocyte content. These findings further support the conclusion that epithelial cells can contribute to inflammatory processes in the nasal mucosa. The findings emphasize the need to identify asymptomatic nasal mucosal inflammation in studies of the nasal mucosa.

Adolescent↗
PubMed1996

[A case of congenital brain tumor diagnosed during follow-up of neonatal intracranial hemorrhage].

We describe a three-year-old girl whose growing congenital brain tumor may have been responsible for her perinatal intracranial hemorrhage. The patient, born after an uneventful pregnancy and delivery, had an intracranial hemorrhage in the right frontal area, including the basal ganglia, as a newborn. Her only symptoms at that time were vomiting and fever. She improved both, clinically and neuroradiologically during the following weeks, and except for mild left hemiparesis, the patient developed with no other apparent neurological deficits. However, a follow-up brain CT scan at 3 years of age, disclosed a heterogeneous tumor with a 5 cm diameter in the same right frontal area as the neonatal hemorrhage. The tumor was surgically removed, and diagnosed as a benign mixed tumor composed of differentiated astrocytoma and meningioma elements. It is conceivable that the brain tumor may have been growing rather slowly since an early fetal stage. This case indicates the need of being aware that neonatal intracranial hemorrhages may be caused by bleeding of congenital brain tumors.

Astrocytoma↗
PubMed1996

[Surgically excised primary mediastinal tumors and cysts: a report of 43 cases].

Forty-three primary mediastinal tumors or cysts were surgically treated in 41 patients during a 10-year period. These tumors consisted of 20 thymic tumors, 10 neurogenic tumors, 5 teratomas, 3 lymphoid tumors, 2 congenital cysts, 2 mediastinal thyroid tumors, and 1 chondroma. There were 16 male and 25 female patients. The mean age was 44 years with a range of 6 to 79 years. Sixteen patients (39%) were symptomatic. There were 20 thymic tumors including 13 thymomas, 5 thymic cysts, and 2 hyperplasia with myastenia. Additional radiation therapy was recommended for all but stage I thymomas. Only 1 of the 10 neurogenic tumors was malignant. Eight teratomas were all cystic and matured. Early operative intervention is mandatory in these cases.

Adolescent↗
PubMed1996

[A case of gastric cancer with peritoneal dissemination and malignant biliary stenosis treated by loco-regional cancer therapy].

A 68-year-old male diagnosed as Borrmann 2 type gastric cancer (T3N3P3H0M0: Stage IVb) was treated by distal gastrectomy and administration of CDDP 50 mg+MMC 10 mg intraperitoneally. After operation intraperitoneal chemotherapy was continued until adhesional ileus occurred four months later. At reoperation peritoneal dissemination was not found either macroscopically or microscopically. After four months, and expandable metallic stent (Wallstent) was applied for malignant biliary stenosis due to lymph node metastasis. Although the patient died 23 months after the first operation, our loco-regional cancer therapy seemed effective for support of quality of life.

Aged↗
PubMed1996

[Surgical case of cerebral pilocytic astrocytoma--clinicopathologic study and analysis of proliferation potential by PCNA staining].

The clinical and the pathological features of a surgical case of adult pilocytic astrocytoma in the right temporal lobe are described. The growth kinetics of the tumor cells were investigated by immunohistochemical staining of Proliferating cell nuclear antigen (PCNA). The patient, a 23-year-old man, was admitted to our hospital with a history of loss of consciousness. A CT scan showed a cystic lesion with enhanced mural nodule in the right temporal lobe. Total resection of the mural nodule including the surrounding cyst wall was performed. Histopathological examination revealed tumor cells exhibiting a biphasic pattern with capillary proliferation and some Rosenthal fibers. Only 8.7% of the tumor cells were PCNA-positive. Pilocytic astrocytoma of the cerebrum is a clearly recognizable, distinctive entity with a natural history and pathological features similar to those of the relatively benign cerebellar astrocytoma of childhood. Standardized assessment of PCNA in pilocytic astrocytomas of the cerebrum may be useful as an independent indicator of biological behavior.

Adult↗
PubMed1996

Electrocardiographic changes after intravenous administration of magnesium in rabbits.

Magnesium (Mg+2) therapy has a beneficial effect in various cardiovascular diseases. However, overdosage of Mg+2 can be fatal. This study was undertaken to determine the amount of Mg+2 that can be safely administered intravenously to rabbits. Twenty New Zealand White rabbits were allotted to three groups. One hundred milliliters of 0.9% NaCl/kg was infused in group-1 rabbits (n = 10) used as a control group. Rabbits in group 2 (n = 6) and group 3 (n = 4) received MgCl2 (2.5 mmol and 5.0 mmol/kg respectively) in 0.9% NaCl (100 ml/kg). The infusion was delivered intravenously for 30 min (group 2, 8 mg/kg per min; group 3, 16 mg/kg per min). The electrocardiogram was monitored throughout the infusion; the P-R interval, QRS duration, and QTc interval of group-2 and group-3 rabbits were prolonged at dosages of 0.8 mmol/kg, 1.7 mmol/kg, and 5.0 mmol/kg of MgCl2 respectively, compared with readings in group-1 rabbits. We hypothesized that the mean +2 standard deviations of the pre-operative baseline values was the safe limit. On the basis of this hypothesis, the safe limit of the P-R interval is 95.3 milliseconds, which corresponds to 0.6 mmol/kg of infused Mg+2; the QRS duration is 44.4 milliseconds, which corresponds to 1.0 mmol of Mg+2/kg; and the QTc interval is 350.0 milliseconds, which corresponds to 3.6 mmol of Mg+2/kg. These results will provide guidance for avoiding cardiac side effects when researchers investigate the effects of Mg+2 in rabbits.

Animals↗
PubMed1996

[A case of benign multiple neurilemmomas in the mediastinum and the chest wall].

A 55-year-old female was admitted to our hospital because of the increase in the size of a left posterior mediastinal tumor after 5 years of observation. The patient also had a chest wall tumor on her left back which had 20 year's history. CT findings suggested the mediastinal tumor and the chest wall tumor were connected through the 4th intercostal space. Pathological specimen obtained by a needle biopsy of the chest wall tumor showed neurilemmoma-like lesion, but malignancy could not be ruled out. With a left posterolateral thoracotomy we removed the mediastinal tumor measuring 3 x 2.5 x 2.5 cm and the extra-thoracic chest wall tumor measuring 7 x 3.5 x 3.5 cm. Intra-operative findings showed these tumors arising from the 4 th intercostal nerve separately had no relevancy. Histological examination of both tumors revealed benign neurilemmoma. Postoperative clinical course was uneventful.

Female↗
PubMed1995

Multiple isoforms of guinea pig decay-accelerating factor (DAF) generated by alternative splicing.

Human decay-accelerating factor (DAF, CD55), which is one of the regulators of complement activation (RCA), prevents complement activation on homologous cell membranes, resulting in a functional discrimination between self cells and invading microorganisms. DAF is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein and has been identified at the molecular level only in primates. We have isolated guinea pig DAF cDNA clones from a spleen library and identified six different classes. All encode the same four short consensus repeat domains with 58% amino acid sequence identity to human DAF, but show variability in the C-terminal region. Alternative splicing of two optional exons generates transmembrane, GPI-anchored, and secreted forms of guinea pig DAF, and differential usage of splice sites in the single exon composed of internally quintuplicated sequences generates variable Ser/Thr-rich regions. Multiple isoforms were expressed ubiquitously in all tissues and cells tested. Similar variability in the Ser/Thr-rich region has been reported in human membrane cofactor protein (MCP), another membrane inhibitor of the RCA family. There seems to be a common ancestral sequence in DAF and MCP consisting of a Ser/Thr-rich region, but obviously multiplication occurred independently, indicating the importance of variability of the Ser/Thr-rich region for the effective regulation of complement activation.

Alternative Splicing↗
PubMed1995

Distinct immunohistochemical localization of IL-4 in human inflamed airway tissues. IL-4 is localized to eosinophils in vivo and is released by peripheral blood eosinophils.

Nasal polyposis and asthma are inflammatory conditions of the airways characterized by infiltration of activated inflammatory cells, particularly eosinophils. IL-4 is a multifunctional cytokine considered to play an important role in eosinophilic inflammation. We examined the cellular distribution of immunoreactive IL-4 in nasal polyps, as well as in the bronchial mucosa of both nonasthmatic control subjects (n = 6) and patients with well-characterized mild asthma (n = 6) subjected to a diluent or an allergen challenge. To determine eosinophilic contribution, tissue sections were counterstained with FITC after IL-4 immunostaining. No eosinophils were observed in the bronchial mucosa of nonasthmatic subjects. Nasal polyp tissues contained approximately 15 times more eosinophils per mm2 compared with bronchial tissues from asthmatics after a diluent challenge. Allergen challenge resulted in a marked increase in eosinophil density in bronchial tissues. A negligible number of cells immunostaining IL-4 was observed in bronchial tissues from nonasthmatic control subjects. The density of IL-4-positive cells in nasal polyp tissues was almost three times greater compared with asthmatics bronchial tissues after a diluent challenge. Approximately 90% of the IL-4-positive cells in bronchial tissues did not exhibit fluorescence after FITC counterstaining; in contrast, about 80% of the IL-4-positive cells in nasal polyp tissues did. We also show that peripheral blood eosinophils from allergic subjects express IL-4 mRNA by Northern blot analysis, particularly on stimulation with secretory IgA immune complexes. Finally, the supernatant of stimulated eosinophils contained approximately 50 pg/10(6) cells of IL-4 as determined by ELISA. These data demonstrate that eosinophils express the message and release IL-4 in vitro, and that these cells are the primary source of immunoreactive IL-4 in tissues undergoing chronic severe mucosal inflammation.

Adult↗
PubMed1995

Isolation of Xenopus LMP-7 homologues. Striking allelic diversity and linkage to MHC.

The mammalian low molecular mass protein-7 (LMP-7) gene resides in the class II region of the MHC, and its product is most probably involved, as a component of a proteasome, in the processing of Ags to be presented by the MHC class I molecules. To elucidate the evolution of the LMP-7 gene at both the primary structure and genetic levels, we isolated LMP-7 cDNA clones from amphibian Xenopus laevis, which last shared a common ancestor with mammals 350 x 10(6) years ago. Two distinctive clones, showing an 85% predicted amino acid sequence identity with each other and 69 to 72% identity with human and mouse LMP-7, were identified from a liver cDNA library of outbred frogs and named XeLMP-7A and XeLMP-7B. XeLMP-7A- and XeLMP-7B-specific probes were used to detect the corresponding genes by using partially inbred frogs with known MHC haplotypes. DNA of the g and j haplotypes hybridized with the XeLMP-7A probe, whereas the f and r haplotype DNA hybridized with the XeLMP-7B probe. These hybridization patterns cosegregated with the MHC haplotypes among offspring of an f/f x f/g cross, and one recombinant revealed that the LMP-7 gene is linked more closely to class II than to class I or class III genes. Taken together, the data indicate that XeLMP-7A and XeLMP-7B are highly diverse alleles at a single locus in the frog MHC. The great allelic diversity can be explained either by coselection with particular class I alleles or by differential silencing of MHC genes in the polyploid X. laevis.

Alleles↗
PubMed1995

Duplication of the MHC-linked Xenopus complement factor B gene.

We have previously reported the molecular cloning of the mammalian major histocompatibility complex (MHC) class III gene, complement factor B (Bf) from Xenopus laevis, and linkage of the gene to the frog MHC. Here, we estimated the copy number of the Xenopus Bf gene by genomic Southern blotting analysis and demonstrated that Xenopus laevis has two copies of the Bf gene. Both genes co-segregated with the MHC-linked HSP70 genes among 19 offspring of an f/r x f/r cross, indicating a close linkage of the two Bf genes to the frog MHC. Both genes are transcribed and contain open reading frames. When compared with the previously determined cDNA sequence (Xenopus Bf A), the predicted amino acid sequence of the second cDNA species (Xenopus Bf B) shows 82% overall identity. Polymerase chain reaction analysis indicated that all of the partially inbred frogs with the f, r, g, and j MHC haplotypes, as well as 12 outbred frogs tested have both Bf genes, suggesting that the duplicated Bf genes are stable genetic traits in Xenopus laevis.

Amino Acid Sequence↗
PubMed1995

Spontaneous rupture of the iliac vein: report of a case.

We report a rare case of a spontaneous rupture of the iliac vein which was then surgically treated with good results. A 66-year-old woman was admitted complaining of leg swelling and lower abdominal pain. On the 3rd day after admission, an operation was performed because of a gradually increasing hematoma in the retroperitoneal space. Laparotomy revealed a 17 mm longitudinal tear on the anterior surface of the left external iliac vein with a thrombus inside the lumen. Most of the previously reported 14 cases of this nature have required emergency operations.

Aged↗
PubMed1995

Monoclonality in gastric lymphoma detected in formalin-fixed, paraffin-embedded endoscopic biopsy specimens using immunohistochemistry, in situ hybridization, and polymerase chain reaction.

Diagnosis of gastric malignant lymphoma remains a challenge, especially when the tissue source is endoscopic biopsy specimens. Once an atypical lymphoid infiltrate is found, demonstration of clonality is the key to establishing a diagnosis of the disease. For this purpose, we evaluated the usefulness of immunohistochemistry, in situ hybridization, and polymerase chain reaction (PCR) using formalin-fixed, paraffin-embedded endoscopic materials from 20 patients with B-cell malignant lymphomas. Template DNA for PCR was obtained by microdissecting Giemsa-stained sections using a serial hematoxylin and eosin section as a guide. Clonal rearrangement bands were demonstrated in 15 of 20 cases (75%) by PCR, whereas expression of monotypic light-chain mRNA was detected in seven of 20 (35%) by in situ hybridization and monotypic light-chain restriction in four of 20 (20%) by conventional immunohistochemistry. Although less sensitive than PCR, in situ hybridization was useful for localizing the expression of target mRNAs with cellular accuracy and with low background staining. In addition, two cases were found to be monoclonal only by in situ hybridization, and not by PCR. The results showed that clonal proliferation is detected with the greatest sensitivity with PCR using small routinely processed biopsy specimens and that a difficulty with the PCR method in terms of cellular localization was partially overcome using a microdissection procedure that provided at least tissue-level accuracy.

Base Sequence↗