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Biomedical subjects

R Kobayashi

Publications and source records attributed to R Kobayashi.

At least 307 records · Page 17Linked to original sources
PubMed1992

Immunoglobulin V gene expression in CD5 B-cell malignancies.

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphomas (SLL) generally are malignancies of CD5 B cells. Immunophenotypic and clinicopathologic data, however, are required to distinguish subtypes that apparently have a different cytogenesis than that of conventional CLL or SLL. In addition to expressing CD5, neoplastic cells of the latter are also distinctive in that they frequently coexpress surface immunoglobulin (Ig), bearing one or more cross-reactive idiotypes (CRIs) (e.g. 17.109, G6,) that commonly are found on monoclonal IgM autoantibodies. The frequent occurrence of such CRIs reflects both the biased rearrangement and subsequent selected expression of Ig V genes with little or no somatic mutation. IgM/L CLL, for example, frequently (8/33) harbor abortive Ig rearrangements involving Humkv325, the VK gene encoding the 17.109-CRI. Also, the VH1 gene(s) encoding the G6 CRI accounts for over 10% of all VH genes and over 60% of all the VH1 genes used in randomly selected common CLL/SLL. Furthermore, comparison with the Ig expressed by nonmalignant G6 CRI+ B cells reveals an apparent restriction in the CDR3 of IgH expressed by G6 CRI+ CLL. Coupled with the observed potential bias in antibody light chain and heavy chain pairing in B-CLL, these data suggest that the autoantibodies expressed in this disease are selected based on antigen-binding activity. Collectively, our studies indicate that nonstochastic Ig V gene rearrangement and subsequent selection may influence the Ig repertoire expressed in this common B-cell malignancy.

Animals↗
PubMed1992

Heterogeneity among Epstein-Barr virus-seropositive donors in the generation of immunoblastic B-cell lymphomas in SCID mice receiving human peripheral blood leukocyte grafts.

Epstein-Barr virus (EBV) is associated with B-cell malignancy in immunosuppressed humans and SCID mice receiving human peripheral blood leukocyte grafts (hu-PBL-SCID). We have further characterized the process of lymphoma development in hu-PBL-SCID mice. We report that EBV-seropositive donors differ markedly in the capacity of their PBL to give rise to immunoblastic lymphomas in SCID mice; some donors (high incidence) generated tumors rapidly in all hu-PBL-SCID mice, other donors (intermediate-low incidence) gave rise to sporadic tumors after a longer latent period (greater than 10 weeks), and some donors failed to produce tumors. B-cell lymphomas arising from high incidence donors were multiclonal in origin, and EBV replication was detected in all tumors. Tumors derived from intermediate-low incidence donors were monoclonal or oligoclonal and often had no evidence of viral replication. All tumors, regardless of the donor, resembled EBV-transformed lymphoblastoid cell lines in surface phenotype but differed from lymphoblastoid cell lines by having less Epstein-Barr nuclear antigen 2 and CD23 expression. The variable patterns of lymphomagenesis seen among different EBV-sero-positive donors may be explained by lower levels of specific immunity to EBV in high incidence donors, permitting activation of EBV replication and potential transformation of secondary B-cell targets. In addition, there may be differences in the transforming potential of EBV infecting different donors. The use of the hu-PBL-SCID model may help predict patients at high risk for posttransplant or acquired immunodeficiency syndrome-associated lymphomas.

Age Factors↗
PubMed1992

Purification and characterization of a new member of the S-100 protein family from human placenta.

A novel Ca(2+)-binding protein which is termed S-100P was purified from human placenta with a hydrophobic column followed by an anion exchange column and reverse phase high performance liquid chromatography (HPLC). Molecular mass of the protein was 10 kDa according to sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Using immunoblotting technique, anti-human calcyclin antibodies did not bind to the S-100P. Isoelectric point of S-100P was pI = 4.6. S-100P did not formed disulfide-linked dimer. Calcium binding ability was proved by UV difference spectrometry, urea/alkaline gel electrophoresis, and 45Ca overlay technique. A ninety amino acid sequence of S-100P was determined. It is 49% identical with human S-100 beta, 38% with human calcyclin, and 37% with human cystic fibrosis antigen.

Amino Acid Sequence↗
PubMed1992

Isolation and characterization of a calcium-binding protein derived from mRNA termed p9Ka, pEL-98, 18A2, or 42A by the newly synthesized vasorelaxant W-66 affinity chromatography.

W-66 (N-(2-aminoethyl)-N-[2-(4-chlorocinnamylamino) ethyl]-5-isoquinolinesulfonamide), a newly synthesized isoquinolinesulfonamide, was shown to have a potent vasodilatory action and calmodulin (CaM)-antagonizing action. Using the W-66 affinity chromatographic technique, we purified two Ca(2+)-binding proteins from the EGTA-soluble fraction of bovine aorta. One was CaM and the other was an acidic protein with a molecular mass of 11 kDa. It was tentatively named "calvasculin." Calvasculin was a dimeric protein. Equilibrium dialysis showed that 1 mol of calvasculin (dimer) bound to 1.98 +/- 0.30 mol of Ca2+ in the presence of 10(-3) M Ca2+. Calvasculin failed to activate Ca2+/CaM-dependent enzymes such as myosin light chain kinase, Ca2+/CaM-dependent phosphodiesterase, or Ca2+/CaM-dependent protein kinase II and to inhibit the CaM stimulation of these enzymes. The partial amino acid sequence of calvasculin revealed a high homology to the predicted protein derived from mRNA, named pEL-98, 18A2, 42A, or p9Ka. We also examined the physicochemical and biochemical properties of calvasculin. Using the antibody specific for calvasculin, we obtained evidence that calvasculin is present in abundance in bovine aorta but not in brain, lung, heart, or testis.

Amino Acid Sequence↗
PubMed1992

Ca(2+)-regulated actin and phospholipid binding protein (68 kD-protein) from bovine liver: identification as a homologue for annexin VI and intracellular localization.

An F-actin binding protein was purified from bovine liver by means of DNase I affinity, hydroxylapatite and DEAE-cellulose column chromatographies. It consisted of a single polypeptide chain having an apparent molecular weight of 68,000 with a Stokes radius of 35 A. Electron microscopy of rotary shadowed specimens showed that the 68 kD protein is a globular protein. This protein showed a higher affinity for F-actin in the presence of Ca2+ than in its absence, which is opposite to the actin-binding property shown by nonmuscle alpha-actinin or fimbrin. The 68 kD protein had no F-actin severing and capping activity. Interestingly, the 68 kD protein was found to aggregate liposomes at micromolar Ca2+ concentrations. Immunoblot analysis and partial protein sequence data identified the 68 kD protein as an annexin VI (p68) homologue. Immunocytochemical studies showed that the 68 kD protein was localized along stress fibers as well as membrane ruffles, microspikes and focal contacts, raising the possibility that annexin VI may contribute to control membrane-microfilament interaction in the cell.

Actins↗
PubMed1992

A follow-up study of 201 children with autism in Kyushu and Yamaguchi areas, Japan.

A follow-up survey was conducted on 201 young adults with autism who were 18 or older (mean age, 21.5). All had participated previously in intensive therapeutic camping or had therapeutic involvement at medical consultation agencies to evaluate their outcome. Their social outcome was better than that previously reported in Japan. Although 31.5% had shown marked deterioration during adolescence, 43.2% had shown marked improvement during that period. Possible factors contributing to these results are discussed.

Adolescent↗
PubMed1992

Immunochemical localization of aminopeptidase M in the alimentary tract of the guinea pig and rat.

Aminopeptidase M (APM) was localized in the kidney and alimentary tract of guinea pigs and rats by indirect immunohistochemistry. APM was detected in the brush border of the epithelium of the proximal convoluted tubule of the kidney and of the small intestine, and it was localized to cells scattered throughout lymphoid tissue in the small intestine and colon. The gastric mucosa was unstained. APM was localized to numerous fibers supplying the myenteric plexus of the stomach, small intestine, and colon. The submucosal plexus was sparsely supplied by immunoreactive fibers. Occasional cell bodies were stained in the myenteric plexus. Staining was abolished by preabsorption of the primary antibody with APM. APM was characterized in membranes prepared from the muscle and mucosa of the guinea pig and rat stomach, small intestine, and colon by Western blotting. The major immunoreactive protein identified in membranes prepared from all tissues had an apparent molecular weight of 140, corresponding to the monomer of APM. In the brush border APM has a digestive function, whereas in neural tissue it may degrade and inactivate neuropeptides.

Aminopeptidases↗
PubMed1992

Purification of a mature form of 60 kDa heat-shock protein (chaperonin homolog) from porcine kidney and its partial amino acid sequence.

1. We have purified a 58 kDa collagen-binding protein from a 4 M guanidine hydrochloride extract of porcine kidney. 2. This protein was identified as a mature form of 60 kDa heat-shock protein (HSP60, chaperonin homolog) based on its partial amino acid sequence. 3. Among 98 determined sequences of the porcine protein, 97 residues were identical with those deduced from nucleotide sequence of the cDNA encoding human HSP60.

Amino Acid Sequence↗
PubMed1992

Transfer of human chronic lymphocytic leukemia to mice with severe combined immune deficiency.

B chronic lymphocytic leukemia (CLL) cells were transferred into mice with severe combined immunodeficiency (SCID). Leukemia cells injected into the peritoneal cavity of these animals may survive for at least 10 weeks in vivo. In contrast, leukemia cells do not survive for long periods when injected intravenously. Despite the longevity of CLL cells injected i.p., these cells apparently do not migrate to other lymphoid tissues. Eight to sixteen weeks after receiving CLL cells, SCID mice develop human IgG autoantibodies to human red blood cells and/or high serum levels of human Ig. Soon thereafter, these animals develop lethal human B-cell tumors. In contrast to the original CLL cells, these human B-cell tumors are CD5-negative, have genomic DNA of Epstein-Barr virus (EBV), express antigens associated with latent EBV infection and have distinctive Ig gene rearrangements by Southern. We conclude that bystander B cells may generate tumors in CLL-reconstituted SCID mice that emulate the EBV-associated lymphoproliferations noted in SCID mice reconstituted with normal human PBL.

Animals↗
PubMed1992

Cortical synaptogenesis in congenitally hydrocephalic HTX-rats using monoclonal anti-synaptic vesicle protein antibody.

We attempted to develop a method for investigating impairment of synaptogenesis quantitatively involving measurement of the fluorescence intensity emitted by immunohistochemically stained rat brain using a monoclonal antibody (Mab 171B5) against a synaptic vesicle protein (SVP-38). We applied this method to congenitally hydrocephalic and non-hydrocephalic brains of HTX-rats, and compared the postnatal changes in the fluorescence intensity in the molecular layer of the cerebral cortex. In non-hydrocephalic HTX-rats, the fluorescence intensity remained nearly unchanged from the 1st to 7th postnatal day and then increased at an almost linear rate until the 21st postnatal day, when it reached 4.5 times the value on the 7th postnatal day. The increase thereafter was gradual until the 28th postnatal day. In hydrocephalic HTX-rats, the fluorescence intensity increased nearly in parallel with that in non-hydrocephalic HTX-rats up to the 21st postnatal day. On the 28th postnatal day, the fluorescence intensity showed a marked reduction (P less than 0.01). This finding indicates that despite the presence of continuous pressure due to progressive ventricular dilatation after birth, synaptogenesis in the cerebral cortex may be relatively resilient.

Aging↗
PubMed1992

Localization of phosphoinositide-specific phospholipase C-alpha in porcine kidney.

The presence of multiple forms of phosphoinositide-specific phospholipase C (PLC), an important enzyme in the cell signal transduction, suggests that specialized functions of tissues and cells may require different modes of PLC regulation. In the present study, we have purified a 54-kDa heparin-binding protein from a 4 M guanidine hydrochloride extract of porcine kidney, and identified it as one of isoenzymes of PLC on the basis of its partial amino acid sequence. Among 194 determined sequences of the porcine protein, 186 residues were identical with those deduced from nucleotide sequence of the cDNA encoding rat PLC-alpha. The subcellular distribution of porcine renal PLC-alpha was examined by Western blotting by using a specific antibody against the purified protein. Quantitation of the Western blots revealed that 70% of PLC-alpha was membrane-associated. Immunohistochemical studies showed a specific localization of PLC-alpha in epithelial cells of distal tubules and collecting ducts of normal porcine kidney, but not in other cells composing the nephron. Moreover, the highest expression of PLC-alpha was observed in apical membranes in these epithelial cells. Thus, this form of PLC is considered to have a specific role in the signal transduction process related to regional renal tubular functions.

Amino Acid Sequence↗
PubMed1992

Gas phase derivatization of ammonia with 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole and its application to urease assay.

An ammonia-specific and rapid fluorometric method for determination of ammonia and urease activity was developed. The method is designed to assay ammonia levels or urease activity for the rapid diagnosis of Helicobacter pylori infection. 4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole was used to derivatize ammonia and 4-amino-7-nitrobenzo-2-oxa-1,3-diazole was analysed by high performance liquid chromatography at an excitation wavelength of 455 nm and an emission wavelength of 520 nm. Derivatization was designed to react with ammonia gas produced in a strong alkaline pH sample. The fluorescent intensity was linear in the range of 0.1-10 mM ammonia per tube when the reaction was carried out for 15 min at 37 degrees C. Urease activity, judged as the amount of ammonia production from urea, could be measured at 25 ng per tube (S/N = 1.5) with Jack bean meal urease. Because of its rapidity, this assay is potentially superior to the current standard method in use in clinical settings.

4-Chloro-7-nitrobenzofurazan↗
PubMed1992

EBV-induced human B cell lymphomas in hu-PBL-SCID mice.

Epstein-Barr virus (EBV) infection is associated with Burkitt's lymphoma (BL) in normal individuals and immunoblastic B cell lymphomas in immunosuppressed or HIV-infected individuals. SCID mice reconstituted with human peripheral blood leukocytes (hu-PBL-SCID) from EBV-seropositive donors also may develop spontaneous B cell lymphomas which histologically and phenotypically resemble post-transplant tumors, and are distinct from BL. These tumors always contain EBV DNA. We have noted three different reproducible outcomes depending upon the EBV-seropositive donor used for generation of hu-PBL-SCID mice: (i) no tumors appear; (ii) tumors appear in a fraction of hu-PBL-SCID mice with a 10-20 wk. latent period; or (iii) tumors appear in all hu-PBL-SCID mice within 6-10 wk. Southern blot analysis of late versus early tumors using a probe specific for the EBV terminal repeat sequences (BamNJ), which allows distinction between circular latent and linear replicating genomes, shows that late tumors do not involve active EBV replication but that early tumors do show replicating genomes. In addition, EBV genomes were monoclonal in late tumors but polyclonal in early tumors. These data suggest two mechanisms for EBV lymphomagenesis, slow outgrowth of rare latently-infected B cells, and more rapid transformation of uninfected bystander B cells by replicating virus. The latter process may be highly amenable to therapy in patients at risk for EBV-related lymphomas. In addition, prospective screening of EBV-seropositive transplant recipients in the hu-PBL-SCID model may predict the risk of post-transplant lymphoma development.

Animals↗
PubMed1992

Glomerular deposition of complex-forming glycoprotein heterogenous in charge (protein HC) in IgA nephropathy.

IgA immune complexes and polymeric IgA are presumed to play important roles in the development and progression of IgA nephropathy. Complex-forming glycoprotein heterogenous in charge (protein HC), being inhibitors of neutrophilic chemotaxis, has been reported as binding to IgA. As a working hypothesis it was assumed that complexes of protein HC and IgA are present in glomeruli from IgA nephropathy patient in stable state. In this study, we examined the glomerular deposition of protein HC in 40 patients with IgA nephropathy and in 10 patients with non-IgA nephropathy. We used highly specific antibody against protein HC, that does not cross-react with alpha-1-microglobulin. An immunofluorescent study revealed that 10 out of the 40 patients (25%) showed an intensity of 1+, 16 (40%) showed weak positive (+/-), and the other 14 (35%) were negative. There was no deposition of protein HC in non-IgA nephropathy patients. Histopathological analysis demonstrated a significant correlation between the intensity of glomerular-deposited protein HC and pathological activity (p less than 0.005); the latter was defined as having either crescents in more than 15% of the remaining glomeruli (excluding global sclerotic glomeruli), or segmental necrosis or sclerosis in more than 30% of the remaining glomeruli. A significant correlation was observed between pathological activity and the intensity of deposited IgG, IgA and IgM (p = 0.01), and lambda chain (p less than 0.005). Considering anti-inflammatory activity of protein HC, these results suggest that protein HC cannot protect sufficiently acute inflammation or tissue damages due to co-deposited IgG and IgM and/or other factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[A case of undifferentiated carcinoma of the thyroid with compression stenosis of the cervical and mediastinal trachea which was dilated by the expandable metallic stents].

The patient was a 64-year-old male with undifferentiated carcinoma of the thyroid which constricted the trachea. The radiation therapy did not reduce the size of the tumor, and did not improve the dyspnea. Bronchoscopy and tomography showed a compression stenosis of the cervical and mediastinal trachea. It was difficult to insert the T-tube because of the large mass of the neck. Therefore, three EMSs were inserted into the stenotic area of the trachea. Immediately after the insertion of the EMSs, the lumen of the trachea was dilated, and the dyspnea was improved. The patient died of the tumor 7 weeks after the insertion of the EMSs. Autopsy showed that the trachea was dilated by EMSs.

Bronchoscopy↗
PubMed1992

[Successful treatment with combination of methylprednisolone, antilymphocyte globulin and cyclosporine in two cases of aplastic anemia].

Two children with severe and moderate aplastic anemia received combination treatment with methylprednisolone, antilymphocyte globulin and cyclosporine. One child (severe type) was given 2 courses of high dose methylprednisolone during the last 4 weeks without improvement prior to this combination therapy. The other child (moderate type) was not previously treated. Both patients showed complete response within 3 months following this therapy. Serious side effects were not observed. Combination therapy of these three drugs may be beneficial for patients with aplastic anemia.

Anemia, Aplastic↗
PubMed1992

[Quantitative fluorescence-immunohistochemistry of presynaptic terminals using a monoclonal antibody against a synaptic vesicle-specific protein (SVP-38) in paraffin sections].

We developed a method for investigating impairment of synaptogenesis quantitatively involving measurement of the fluorescence intensity emitted by immunohistochemically stained paraffin sections of rat brain using a monoclonal antibody (Mab 171B5) against a synaptic vesicle protein (SVP-38). We applied this method to congenitally hydrocephalic and non-hydrocephalic brains of HTX-rats, and compared the postnatal changes in the fluorescence intensity in the molecular layer of the cerebral cortex. In non-hydrocephalic HTX-rats, the fluorescence intensity remained nearly unchanged from the 1st to 7th postnatal day and then increased at an almost linear rate until the 21st postnatal day, when it reached 4.5 times the value on the 7th postnatal day. The increase thereafter was gradual until the 28th postnatal day. In hydrocephalic HTX-rats, the fluorescence intensity showed a marked reduction on the 28th postnatal day (p < 0.01). This finding indicated impairment of synaptogenesis. We believe that this method provides useful information for evaluating the impairment of synaptogenesis in various pathological conditions in mammarian brains. The basic aspects of this method which support its validity are also discussed.

Animals↗