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Biomedical subjects

M Nonaka

Publications and source records attributed to M Nonaka.

At least 199 records · Page 11Linked to original sources
PubMed1993

Functional properties of the allotypes of mouse complement regulatory protein, factor H: difference of compatibility of each allotype with human factor I.

Three allotypes of mouse factor H, H.1, H.2, and H.3 were purified from the sera of mice with different factor H allotypes, and their functional properties were investigated. The three allotypes all bound to heparin, DNA, Con A, and methylamine-treated mouse C3 (C3(MA)mo) with similar affinities for each protein immobilized, showed identical mobilities on SDS-PAGE, and were reacted well with rabbit polyclonal antibody against H.1 and H.2. Factor I-cofactor activity of these factor H allotypes was measured using highly purified material of mouse, guinea-pig, and human origin. In a homologous system, these allotypes expressed indistinguishable mouse factor I (Imo)-cofactor activity for the cleavage of C3(MA)mo. Imo-cofactor activity was again indistinguishable in these allotypes when methylamine-treated human C3 (C3(MA)hu) or methylamine-treated guinea-pig C3 (C3(MA)gp) was substituted for the C3(MA)mo substrate. The cofactor activity of these factor H allotypes, however, was augmented 4-5 times if C3(MA)hu) was used instead of C3(MA)mo, and was barely detected if C3(MA)gp was employed. In contrast, differences in the potency of the cofactor activity for the three allotypes were revealed if human factor 1 (Ihu) was substituted for Imo: the order of the efficiency for the cleavage of C3(MA)hu was H.2 > H.1 = H.3. These results, taken together with the finding that the homologous combinations of mouse and human factors H and I expressed greater activity for the cleavage of C3(MA)hu than did the heterologous combinations of factor H and factor I, suggest that mouse factor H allotypes discriminate species of protease factor I but not those of substrate (C3(MA), and H.2 possesses the best compatibility for Ihu in C3(MA)hu inactivation.

Animals↗
PubMed1993

MEN type 1 associated with mediastinal carcinoid producing parathyroid hormone, calcitonin and chorionic gonadotropin.

A 34-year-old Japanese woman was admitted to our hospital with a mediastinal tumor. Laboratory data showed high levels of calcitonin (CT), human chorionic gonadotropin (hCG) and parathyroid hormone (PTH) in the serum. Surgery was performed, but the tumor could not be completely resected. The patient died in the 10th postoperative month due to systemic metastasis and cachexia. At autopsy, diffuse parathyroid hyperplasia and multiple islet cell tumors of the pancreas were found. A pathological diagnosis of multiple endocrine neoplasia (MEN) type 1 associated with mediastinal atypical carcinoid tumor was made. Immunohistochemical study indicated the tumor cells of the mediastinum to be positively stained for hCG beta but not for PTH or CT. The tumor tissue contained significantly high levels of CT, PTH and whole hCG. This is the first case report on MEN type 1 associated with mediastinal carcinoid tumor producing PTH, CT and hCG beta.

Adenoma, Islet Cell↗
PubMed1993

Detection of DNA in the nucleoids of chloroplasts and mitochondria in Euglena gracilis by immunoelectron microscopy.

DNA in the nucleoids of chloroplasts and of mitochondria in Euglena gracilis was detected with anti-DNA antibodies by immunoelectron microscopy. After treatment with the antibodies, DNA in these organelles combined with gold particles that had been coated with anti-IgM antibodies such that it was possible to trace the outlines of the nucleoids. Nucleoids in chloroplasts appeared to be composed of twisted threads 50-70 nm in diameter. The twisted threads were entangled to form thicker nodes of 100-200 nm diameter. Most nucleoids in mitochondria were spherical or ovoid, 70-130 nm in diameter. Nucleoids both in chloroplasts and in mitochondria contained cores with which DNA threads were in tight contact. The structure of the nucleoids was very different from those previously observed by conventional electron microscopy.

Animals↗
PubMed1993

[Vestibular immune injury related to perilymph antigen specific antibody levels in the guinea pig].

This study demonstrates that degeneration of vestibular sensory cells depends on the integrity of immune responses in the endolymphatic sac (ES). Degeneration of the saccule occurred nearly twice as often as degeneration of the utricle and ampulla. Perilymph antibody levels were assessed following direct antigen (KLH) challenge to the endolymphatic sac in systemic presensitized guinea pigs. Mean perilymph antibody levels were significantly elevated in ears showing degeneration as compared to those which did not. Serum anti-KLH antibody levels were also significantly elevated in the ears with degeneration as compared to those without. Whether degeneration or recovery occurs, is largely dependent on the level of systemic immunization and perilymph antibody level within one week of antigen challenge to the ES.

Animals↗
PubMed1993

[Surgical treatment of tuberculous abscess in chest wall].

A case of chest wall tuberculosis with empyema is reported. A 45-year-old woman with a history of right lung pleuritis was admitted to our hospital with right shoulder pain. The chest X-ray film showed abnormal shadow in the right lower lung field. Chest CT revealed right posterior chest wall abscess and localized empyema. Bacterial examination of the chest wall abscess obtained by needle aspiration biopsy disclosed positive acid-fast bacilli. Three months after starting antituberculous therapy with INH, RFP and SM, the chest wall abscess had been increased and abscess drainage was performed. After two months of tube drainage, the abscess was diminished in size and enucleation with primary closure was performed. Antituberculous chemotherapy was continued. One year after surgery, no sign of recurrence was observed and the residual empyema was decreased.

Abscess↗
PubMed1993

[Prospective dose-escalation study in stereotactic radiotherapy utilizing a linear accelerator: report from East Hokkaido Radiosurgery Study Group (EHRSSG)].

Stereotactic radiotherapy utilizing a linear accelerator has been investigated. (1) Radiosurgery, (2) fractionated stereotactic radiotherapy, and (3) fractionated radiotherapy followed by stereotactic boost have been performed according to pathology, size, and prognosis of diseases. Accuracy in localization of the treatment center was within one millimeter using a CT simulator. From July, 1990 to December 1992, 69 lesions in 63 patients have been treated using the stereotactic radiotherapy according to prospective dose-escalation design. Five patients have experienced transient worsening of nerve palsy or headache, but these complications were self-limited. No late radiation damage was observed over a mean follow-up period of 12.5 months. Encouraging improvements were obtained in patients with metastasis, AVM, and acoustic neurinoma although the follow-up period was too short to be conclusive. Stereotactic radiotherapy utilizing a linear accelerator is thus suggested as a safe and effective approach providing that dose-volume-time relationship is well controlled.

Adolescent↗
PubMed1992

Insertion of the B2 sequence into intron 13 is the only defect of the H-2k C4 gene which causes low C4 production.

The serum level of the fourth component of complement (C4) in mice bearing H-2k haplotype is only 1/10 of that of non-H-2k mice. H-2k bearing mice, but not non-H-2k bearing mice, have an insertion of the B2 sequence into intron 13 of the C4 gene, and aberrant C4 mRNA in liver apparently generated by abnormal RNA splicing caused by the insertion of the B2 sequence. To test the possible causal relationship between the B2 insertion and low C4 production in H-2k mice directly, we constructed the H-2k C4 gene without the B2 insertion and the H-2w7 (non-H-2k) C4 gene with the B2 insertion by exchanging a part of intron 13 between these two genes. Transfection of the intact H-2w7 C4 gene or the chimeric H-2k gene without the B2 insertion into HepG2 cells resulted in the production of only normal C4 mRNA at the normal level. On the other hand, the intact H-2k C4 gene or the chimeric H-2w7 C4 gene with the B2 insertion directed production of both aberrant and a decreased amount of normal C4 mRNA. These results demonstrated that the insertion of B2 sequence into intron 13 of the C4 gene is the only determinant of low C4 production by H-2k mice through aberrant RNA processing.

Animals↗
PubMed1992

Complete complementary DNA sequence of the third component of complement of lamprey. Implication for the evolution of thioester containing proteins.

Lamprey liver mRNA sequences were amplified by reverse transcriptase-polymerase chain reaction using primers synthesized according to the amino acid sequences at the thioester region common to the mammalian C3, C4, and alpha 2-macroglobulin (alpha 2M). Two different cDNA species were identified that showed a close similarity to the mammalian C3 or alpha 2M sequences, respectively. Using the C3-like sequence as a probe, two overlapping cDNA clones were isolated from the lambda ZAP library, which together covered the entire region encoding the putative lamprey pro-C3. The deduced amino acid sequence of the putative lamprey pro-C3 contained 1660 amino acids and showed 31%, 22%, 23%, and 16% amino acid sequence identity with mouse C3, C4, C5, and human alpha 2M, respectively. The distributions of cysteine residues were completely identical between the mouse C3 and the putative lamprey C3 except that the lamprey sequence had two additional cysteine residues in the alpha-chain. The possible beta-alpha and alpha-gamma processing sites were found at exactly the same positions as in mammalian C4. These results suggest that the putative lamprey C3 retains a close similarity to the common ancestor of the mammalian C3 and C4, which appeared to have had a three-subunit chain structure.

Amino Acid Sequence↗
PubMed1992

Aberrant splicing caused by the insertion of the B2 sequence into an intron of the complement C4 gene is the basis for low C4 production in H-2k mice.

The serum level of the fourth component of complement (C4) in mice bearing the H-2k haplotype is only 1/10 to 1/20 of that of non-H-2k mice. We have analyzed C4 cDNA clones from B10.BR(H-2k) mouse liver and found aberrant C4 cDNA which contained a 200-base pair (bp) insertion between the exon 13 and exon 14 encoded sequences in addition to the normal C4 cDNA. The 5' 148 bp and the 3' 52 bp of this insert were derived from the B2 sequence, the short interspersed repeats of mouse genome, and the central part of intron 13, respectively. Sequence analysis of intron 13 of the C4k gene showed the presence of a complete copy of a B2 consensus sequence. The structure of aberrant C4 mRNA indicated that the possible 3' splice site in the B2 sequence and the cryptic 5' splice site in intron 13 were used. Both the insertion of the B2 sequence into intron 13 and the presence of aberrant mRNA in the liver were specific to H-2k-bearing mice, suggesting that the aberrant splicing due to the B2 insertion is the basis for low C4 expression in H-2k mice.

Animals↗
PubMed1992

Covalent binding of C3b to C4b within the classical complement pathway C5 convertase. Determination of amino acid residues involved in ester linkage formation.

C5 convertase of the classical complement pathway is a protein complex consisting of C4b, C2a, and C3b. Within this complex C3b binds to C4b via an ester linkage. We now present evidence that the covalent C3b-binding site on human C4b is Ser at position 1217 of C4. We also show that formation of the covalently linked C4b.C3b complex occurs in the mouse complement system and that the C3b-binding site on mouse C4b is Ser at position 1213 which is homologous to Ser-1217 of human C4. Therefore, covalent binding of C3b to a single specific site on C4b within the classical pathway C5 convertase is likely a common phenomenon in the mammalian complement system. Specific noncovalent association of metastable C3b with C4b would occur first, leading to reaction of the thioester with a specific hydroxy group. This is supported by two lines of experimental evidence, one which shows that a mutant C4 that does not make a covalent linkage with C3b is still capable of forming C5 convertase and a second in which the C4b.C3b complex has been demonstrated by cross-linking erythrocytes bearing this C5 convertase.

Amino Acid Sequence↗
PubMed1992

Molecular cloning of mouse beta 2-glycoprotein I and mapping of the gene to chromosome 11.

beta 2-Glycoprotein I (beta 2 GPI), a plasma protein that binds to anionic phospholipids, is composed of five repeating units called a short consensus repeat (SCR), which is found mostly in the regulatory proteins of the complement system. Recently the human beta 2 GPI gene has been assigned to chromosome 17, not to chromosome 1 where most of the genes of the SCR-containing proteins are clustered. In this report, we have isolated a full-length cDNA clone of mouse beta 2 GPI and determined the chromosomal localization of the gene. The amino acid sequence deduced from the nucleotide sequence of mouse beta 2 GPI revealed 76.1% identity with that of human beta 2 GPI. A genetic mapping by in situ hybridization and linkage analysis using 50 backcross mice has shown that the mouse beta 2 GPI gene (designated B2gp1) is located on the terminal portion of the D region of chromosome 11, closely linked to Gfap, and is 18 cM distal to Acrb, extending a conserved linkage group between mouse chromosome 11 and human chromosome 17. On the basis of these results, the evolutionary relationships among the SCR-containing proteins are discussed.

Amino Acid Sequence↗
PubMed1992

Vestibular disorders following immune response of the endolymphatic sac in the guinea pig.

The effect of a direct antigen challenge to the endolymphatic sac on vestibular function was investigated in guinea pigs. Following keyhole limpet hemocyanin (KLH) challenge to the sac in systemically presensitized guinea pigs, caloric responses were examined in 18 animals on days 1, 7, 14, 21, and 28. Caloric responses were significantly suppressed in 13 animals by day 7; of these, 5 animals had recovered by day 14 and 8 animals had not yet recovered by day 28. The behavior of spontaneous nystagmus was examined every hour in 10 animals at intervals of 3 to 56 hours after sac challenge. Irritative spontaneous nystagmus preceding paralytic nystagmus appeared in 5 animals, for which the mean onset was 14.6 +/- 3.1 hours and the mean duration was 4.4 +/- 6.5 hours. Paralytic spontaneous nystagmus appeared in all animals, for which the mean onset time was 23.3 +/- 12.3 hours. Neither direct KLH primary challenge of the sac nor phosphate-buffered saline injection to the sac caused significant changes in the vestibular function. These results suggest that an immune response of the sac induces a vestibular disorder and may produce an attack of vertigo similar to that of Meniere's disease.

Aged↗
PubMed1992

[Two cases of broncholithiasis removed by bronchofiberscopy].

Two cases of broncholithiasis, removed bronchoscopically, are reported. Case 1 was a 38-year-old female who was admitted with hemoptysis. The chest tomogram showed calcification near the right middle lobe bronchus. Bronchoscopy revealed a broncholith in B4. Component analysis showed that more than 98% of this stone consisted of calcium carbonate. Case 2 was a 75-year-old male who was hospitalized because of continuous cough. The chest radiograph showed calcification and atelectasis in the right upper lobe. Bronchoscopically, right B3 was obstructed by a broncholith. After removal of the stone, the distal part of B3 was noted to be filled with pus. Analysis of the stone's composition revealed calcium phosphate (77%) and calcium carbonate (23%).

Adult↗
PubMed1992

[Lobular carcinoma of the male breast--a case report].

Lobular carcinoma of the male breast is very rare, because lobules do not exist in the male mammary gland. Seven cases of lobular carcinoma of the male breast have been reported in Europe and U.S.A., although no case in Japan. We encountered a very rare case of the lobular carcinoma of 74-year-old male breast. Histopathological examinations of both primary tumor and recurrent tumors of the skin led to the diagnosis of lobular carcinoma.

Aged↗
PubMed1991

Differential expression of the five C4-related genes of H-2w7 mice.

Mice bearing the H-2w7 haplotype have five C4-related genes, one C4, one Slp, and three C4/Slp hybrid genes. The expression of these five genes in the liver of H-2w7 mice was estimated at the steady state level of their respective mRNA. We have amplified by the polymerase chain reaction (PCR) three regions of the C4/Slp mRNA where some of these five genes show nucleotide substitution. A relative amount of each gene product was estimated by single-strand conformation polymorphism (SSCP) analysis or by direct counting of the number of respective clones after subcloning into a plasmid vector. A steady state level of the C4 mRNA was most abundant among C4-related gene transcripts. The hybrid 1 and 3 genes were expressed at a similar level which is about 1/2-1/3 of the C4 level. The hybrid 2 gene was expressed at about 1/5 of the hybrid 1 or 3 level. Neither male nor female H-2w7 mice expressed the Slp gene. These results showed that the expression of the five C4-related genes of H-2w7 mice is differentially regulated in spite of the close similarity in the nucleotide sequences in both the 5' flanking and coding regions of these genes.

Animals↗