Search PubMed⌕ Search

Biomedical subjects

N Arai

Publications and source records attributed to N Arai.

At least 181 records · Page 10Linked to original sources
PubMed1992

The carboxyl terminus of RAP30 is similar in sequence to region 4 of bacterial sigma factors and is required for function.

Transcription factor beta gamma (RAP30/74) from rat liver was previously shown in biochemical studies to control the binding of RNA polymerase II to promoters by a mechanism analogous to that utilized by bacterial sigma factors, by decreasing the affinity of polymerase for nonpromoter sites on DNA and by increasing the affinity of the enzyme for the preinitiation complex (Conaway, R. C., Garrett, K. P., Hanley, J. P., and Conaway, J. W. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 6205-6209). By constructing and analyzing mutants of beta gamma, we have identified a novel functional domain located in the carboxyl terminus of the gamma (RAP30) subunit. This domain shares sequence similarity with region 4 of bacterial sigma factors; in particular, it exhibits striking similarity to the carboxyl-terminal regions 4.1 and 4.2 of SpoIIIC (Bacillus subtilis sigma k). Evidence from biochemical studies argues that a mutant gamma (RAP30), lacking amino acid sequences similar to sigma homology region 4.2, is able to assemble with the beta (RAP74) subunit to form a mutant beta gamma (RAP30/74) with impaired ability to interact with RNA polymerase II.

Amino Acid Sequence↗
PubMed1992

Phenol-treatment and a homologous pairing-assay.

Homologous pairing is a key step in homologous genetic recombination. In the early stage of trials for the identification of homologous pairing-promoting proteins from a fission yeast, Schizosaccharomyces pombe, we treated DNA products with phenol in the presence of a salt for the removal of tightly bound proteins from DNA before the assay, but we found that this treatment caused very efficient protein-independent double-strand formation from complementary single-stranded DNAs. Using an assay including the phenol treatment, we detected another species of apparent homologous pairing-promoting proteins in the nuclei, in addition to a homologous pairing-promoting protein consisting of three components which we reported previously. However, studies involving the use of an assay without the phenol-treatments revealed that the second one was not really a homologous pairing-protein. Thus, the protein-independent double-strand formation by phenol-treatment in the presence of a salt could cause the erroneous identification of homologous pairing-promoting proteins.

Bacteriophages↗
PubMed1992

Identification of two types of homologous DNA pairing activity in mouse cells.

We have identified two types of homologous DNA pairing activity in mouse cell extracts by a strand-transfer assay. Both activities are separated from each other by anion-exchange chromatography; neither of them needs ATP. One requires magnesium ion and is stimulated by Escherichia coli single-stranded DNA binding protein, whereas the other does not require the ion and shows a higher affinity for a left-handed Z-DNA.

Adenosine Triphosphate↗
PubMed1992

The role of swollen astrocytes in human brain lesions after edema--an immunohistochemical study using formalin-fixed paraffin-embedded sections.

Swollen astrocytes (SAs) in the white matter after brain edema were immunohistochemically studied in cases with cerebral vascular events, brain tumor and protracted non-missile head injury. SAs showed a decrease in reactivity to glial fibrillary acidic protein (GFAP) and, on the other hand, were positive for laminin, an extracellular matrix glycoprotein known to be secreted by astrocytes. SAs in protracted lesions were strongly positive for both vimentin and plasma proteins including IgG, IgM, C3d and C4d. Remarkable vimentin expression in SAs, instead of GFAP, strongly suggests that SAs are not going to degenerate but are bearing up to regenerate in such circumstances. A number of vimentin-positive buttons also appeared in such protracted lesions, demonstrating disintegration of the processes of SAs. Immunohistochemical detection of plasma proteins in SAs are believed to indicate a facilitated activation in SAs to transform to macrophage-like cells and to act as phagocytes. In addition, demonstration of laminin may suggest hyperactivity of laminin production in SAs after both axonal injury and concomitant edema in order to stimulate neuritic regeneration.

Antibodies↗
PubMed1992

An 11-base-pair DNA sequence motif apparently unique to the human interleukin 4 gene confers responsiveness to T-cell activation signals.

We have identified a DNA segment that confers responsiveness to antigen stimulation signals on the human interleukin (IL) 4 gene in Jurkat cells. The human IL-4 gene, of 10 kilobases, is composed of four exons and three introns. A cis-acting element (P sequence) resides in the 5' upstream region; no additional DNA segments with enhancer activity were identified in the human IL-4 gene. For further mapping purposes, a fusion promoter was constructed with the granulocyte/macrophage colony-stimulating factor basic promoter containing 60 base pairs of sequence upstream from the cap site of the mouse granulocyte/macrophage colony-stimulating factor gene and various lengths of the 5' upstream sequence of the IL-4 gene. The P sequence was located between positions -79 and -69 relative to the transcription start site of the human IL-4 gene, and this location was confirmed by base-substitution mutations. The plasmids carrying multiple copies of the P sequence showed higher responsiveness to the stimulation. The binding protein(s) that recognize the P sequence of the IL-4 gene were identified by DNA-mobility-shift assays. The binding of NF(P) (a DNA binding protein that specifically recognizes the P sequence) to the P sequence was abolished when oligonucleotides carrying base substitutions were used, indicating that the NF(P) interaction is sequence-specific and that binding specificity of the protein paralleled the sequence requirements for IL-4 expression in vivo. The P sequence does not share homology with the 5' upstream sequence of the IL-2 gene, even though surrounding sequences of the IL-4 gene share high homology with the IL-2 gene. We conclude that a different set of proteins recognize IL-2 and IL-4 genes.

Animals↗
PubMed1992

A multicomponent protein of a fission yeast that promotes joint molecule formation from homologous DNAs.

We developed a quantitative assay ("homologous pairing gel assay") adequate for the purification of the activity promoting the formation of joint molecules, an intermediate of homologous recombination ("homologous pairing"). With this assay, one can measure the extent of homologous pairing between a single-stranded DNA and a strand of 3H-labeled double-stranded DNA by crude enzyme preparations. Since the total activity did not significantly change during the sporulation process, we tried to purify the activity from a whole cell extract of mitotic cells of a fission yeast, (Schizosaccharomyces pombe). Through quantitative assaying of a single fraction or of mixed fractions, we obtained three fractions, all of which were required for the maximum level of the ATP-independent homologous pairing: Fractions 65, 100, and 30. In Fractions 100 and 30, polypeptides of approximately 100 and approximately 30 kDa (the 100- and 30-kDa polypeptides), respectively, were the sole detectable components. Fraction 65 contained a polypeptide of approximately 65 kDa (the 65-kDa polypeptide) as the major component and also small amounts of the 30- and 100-kDa polypeptides. Fraction 65 by itself promoted homologous pairing, but the reaction was saturated at a level of approximately 20% of the maximum level achieved with the recA protein. Even when added in excess, Fraction 30 or 100 alone did not promote detectable homologous pairing. A mixture of Fractions 65 and 100 at a rather strict optimum ratio only promoted homologous pairing, the level being 50-70% that with the recA protein, suggesting a stoichiometric complex of these polypeptides as the active form. Fraction 30 alone did not enhance the reaction with Fraction 65, but stimulated homologous pairing promoted by the optimum mixture of Fractions 65 and 100 to the maximum level achieved with the recA protein. Therefore, the homologous pairing-promoting protein from the fission yeast is likely to be a multicomponent protein.

Chromatography, Affinity↗
PubMed1992

Peculiar axonal debris with subsequent astrocytic response (foamy spheroid body). A topographic, light microscopic, immunohistochemical and electron microscopic study.

Foamy spheroid bodies (FSBs) are described, as newly identified pathological structures occurring in human brain. FSBs favoured the substantia nigra pars reticulata (SNPR) and/or globus pallidus (GP) in degenerative conditions especially postencephalitic parkinsonism, progressive supranuclear palsy, pallido-nigro-luysial atrophy and multiple system atrophy. No FSBs were observed anywhere in the presence of substantia nigra pars compacta (SNPC) degeneration, such as occurs in idiopathic Parkinson's disease, or luysio-pallidal system degeneration, such as found in dentato-rubro-pallido-luysial atrophy or Joseph's disease. FSBs were also occasionally identified in the substantia nigra (SN) and/or GP of aged persons. In addition to SN and GP lesions, FSBs were seen in diffuse axonal lesions of long fibre tracts (the corpus callosum, the superior cerebellar peduncle) after non-missile head injuries, and in peri-infarct lesions. Under the light microscope, FSBs appear as slightly eosinophilic, foamy and nearly round objects with vague outlines, measuring approximately 10-50 microns in diameter. Some FSBs contain coarse, eosinophilic clusters at their periphery. FSB stained black when stained by the Gallyas silver method. Some FSBs were immunohistochemically positive for synaptophysin and 68 kDa neurofilament. Glial fibrillary acidic protein-positive fibres were observed alongside and/or inside some FSBs. Electron microscopically, FSBs were found to consist of collections of neuritic debris containing a variety of dense bodies and a small number of both mitochondria and neurofilaments. Some such collections were surrounded by astrocytic processes. These findings strongly suggest that FSBs are collections of small axonal debris destined for removal by astrocytes in due course. A variety of factors (degeneration of the SNPR and/or the GP, injury, infarction, ageing) seemed to be responsible for the histogenesis of FSBs.

Adult↗
PubMed1992

Immunohistochemical expression of microtubule-associated protein 5 (MAP5) in glial cells in multiple system atrophy.

An immunohistochemical study focusing on glial cells was performed using monoclonal antibodies against microtubule-associated proteins (MAP1, MAP2 and MAP5), transferrin, leukocyte common antigen (LCA) and glial fibrillary acidic protein (GFAP) in 5 cases of multiple system atrophy (MSA) exhibiting olivopontocerebellar atrophy and striatonigral degeneration. An antibody to MAP5, a fetal antigen in developing brain, was strongly demonstrated in the glial cytoplasmic inclusions (GCIs) which have recently drawn a great deal of attention and were observed in all 5 cases of MSA. Moreover, MAP5-positive glial cells (MAP5-Gs) were present in significantly higher number than in the controls in various regions where GCIs were found, predominantly in putamen, substantia nigra, cerebellar white matter and internal capsule. LCA and transferrin, markers of microglia and oligodendroglia, respectively, were immunohistochemically detected in some MAP5-Gs. GFAP, on the other hand, was not expressed in MAP5-Gs at all. These findings suggest that MAP5-Gs consist of reactive microglia and oligodendroglia. Our study is the first to demonstrate immunohistochemical detection of MAP5 in glial pathological changes in MSA.

Aged↗
PubMed1992

Activation of lymphokine genes in T cells: role of cis-acting DNA elements that respond to T cell activation signals.

Activation of T cells is initiated by the recognition of antigen on antigen presenting cells to exert the effector functions in immune and inflammatory responses. Two types of helper T cell (Th) clones (Th1 and Th2) are defined on the basis of different patterns of cytokine (lymphokine) secretion. They determine the outcome of an antigenic response toward humoral or cell-mediated immunity. Although lymphokine genes are coordinately regulated upon antigen stimulation, they are regulated by the mechanisms common to all as well as those which are unique to each gene. For most lymphokine genes, a combination of phorbol esters (phorbol 12-myristate 13 acetate, PMA) and calcium ionophores (A23187) is required for their maximal induction. Yet phorbol ester alone or calcium ionophore alone produce several lymphokines. The production of the granulocyte-macrophage colony stimulating factor (GM-CSF) is completely dependent on the two signals. We have previously found a cis-acting region spanning the GM-CSF promoter region (positions -95 to +27) that confers inducibility to reporter genes in transient transfection assays. Further analysis identified three elements required for efficient induction, referred to as GM2, GC-box and conserved lymphokine element (CLE0). GM2 defines a binding site for protein(s) whose binding is inducible by PMA. One protein, NF-GM2 is similar to the transcription factor NF-kB. GC-box is a binding site for constitutively bound proteins. CLEO defines a binding site for protein(s) whose optimum binding is stimulated by PMA and A23187. Viral trans-activators such as Tax (human T cell leukemia virus-1, HTLV-1) and E2 (bovine papilloma virus, BPV) proteins are other agents which activate lymphokine gene expression by bypassing T cell receptor (TCR) mediated signaling. The trans-activation domain of E2 and Tax is interchangeable although they have no obvious sequence homology between them. The viral trans-activators appear to target specific DNA binding protein such as NF-kB and Sp1 to cis-acting DNA site and promote lymphokine gene expression without TCR-mediated stimulation.

Animals↗
PubMed1992

[Effect of tranilast, an anti-allergic drug, on the human keloid tissues].

We studied the inhibitory effects of tranilast, an anti-allergic drug, on the human keloid tissues implanted into the dorsal skin of athymic nude mice and on the growth of keloid fibroblast in vitro. In the keloid tissue-implanted model, tranilast (50-200 mg/kg, p.o.) decreased the weight of the keloid tissue as triamcinolone (25 mg/kg, p.o.) did. Tranilast (200 mg/kg, p.o.) reduced the hydroxyproline content of implanted tissues. Tranilast (3-300 microM) also inhibited the collagen synthesis by keloid fibroblast in vitro. Only a high concentration of tranilast (300 microM) suppressed the glycosaminoglycan synthesis and cell proliferation of keloid fibroblasts. Moreover, tranilast scarcely affected the fibronectin production. Triamcinolone (10 microM) also inhibited glycosaminoglycan synthesis and cell proliferation. These results suggest that the inhibitory effect of tranilast on the keloid tissues is related to its inhibition of the collagen synthesis of fibroblasts. Tranilast would be useful as a therapeutic drug for the treatment of keloids.

Animals↗
PubMed1992

The mechanism involved in the inhibitory action of tranilast on collagen biosynthesis of keloid fibroblasts.

Tranilast, an anti-allergic drug inhibiting the release of substances such as histamine and prostaglandins from mast cells, was previously reported to suppress collagen synthesis of fibroblasts derived from keloid tissues. However, the inhibitory mechanism on collagen synthesis is unknown. We studied its inhibitory mechanism on collagen synthesis by culturing fibroblasts from keloid and hypertrophic scar tissues of humans. Collagen synthesis of fibroblasts from keloid and hypertrophic scar tissue is greater than that from healthy human skin. Tranilast (3-100 microM) did not inhibit prolyl hydroxylase (the rate-limiting enzyme in collagen synthesis) activity. Tranilast (3-300 microM) suppressed the collagen synthesis of fibroblasts from keloid and hypertrophic scar tissue but not healthy skin fibroblasts. Tranilast (30-300 microM) inhibited the release of transforming growth factor (TGF)-beta 1 from keloid fibroblasts, which enhances the collagen synthesis of keloid fibroblasts. Anti-TGF-beta 1 antibody (50 microliter/ml) inhibited the collagen synthesis, although diphenhydramine (10 microM) and indomethacin (10 microM) did not show any inhibition. These results suggest that tranilast inhibits collagen synthesis of fibroblasts from keloid and hypertrophic scar tissue through suppressing the release of TGF-beta 1 from the fibroblasts themselves.

Cicatrix↗
PubMed1992

[Clinical studies of recombinant human granulocyte colony-stimulating factor in elderly patients with malignant lymphoma].

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was given in combination with chemotherapy in elderly patients (greater than or equal to 65 years old) with malignant lymphoma, and the therapeutic efficacy and the incidence of side effects were determined. The subjects consisted of 5 males and 8 females with a median age of 74 years. One patient had Hodgkin's disease and 12 had non-Hodgkin's lymphoma. Regarding lymphoma stage, 2 were in stage II, 3 were in stage III, and 8 were in stage IV. The chemotherapy used was COP-BLAM in 8 patients, COP-BLAM III in 2, IMV-triple P in 2, and ACVP-16 in 1. Treatment with rhG-CSF (1.5 micrograms/kg/day) was commenced during or after the 2nd course of chemotherapy when the neutrophil count dropped to greater than or equal to 1,000/microliters, and was continued until the recovery of either the neutrophil or leukocyte count to 10,000/microliters or 20,000/microliters, respectively. The neutrophil nadir in the non-G-CSF group was 367.3 +/- 231.6/microliters. In the G-CSF group it was 754.6 +/- 116.4/microliters for the second course, with the difference between the 2 groups being significant (p less than or equal to 0.05). Also, the following time periods were significantly shorter in the G-CSF group than the non-G-CSF group: 1) the duration of a neutrophil count less than 1,000/microliters, 2) the duration of fever (greater than or equal to 37.5 degrees C), and 3) the time to recovery from the neutrophil nadir.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Non-Hodgkin's lymphoma in an elderly patient complicated by cyclophosphamide-induced allergic hepatic dysfunction].

A 77-year-old male presented at our Department of Urology in August 1990 with a gradually enlarging swelling in the right scrotum. On August 21, right high orchietomy was performed. This was diagnosed histologically as non-Hodgkin's lymphoma (diffuse large cell type), and the patient was transferred to our department on September 11 for further examination and treatment. As enlargement of the lymph nodes around the abdominal aorta was evident, it was diagnosed as stage IIA according to the Ann Arbor Classification. Beginning on September 21, three courses of COP-BLAM therapy (CPM, VCR, PDN, BLM, ADR, PCZ) were administered (the third course started on November 8) to achieve complete remission. Hepatic dysfunction appeared, however, from November 16, and by November 19, GOT and GPT increased to 6700 and 2120, respectively, with aggravation of jaundice. PDN therapy was instituted, and GOT and GPT improved gradually, but jaundice did not improve. On December 22, laparoscopy was performed, and liver biopsy produced histologic findings of drug-induced hepatitis. Further, lymphoblastic response was positive for CPM. Hepatic failure occurred on December 29, and plasma exchange was performed, but it failed to improve the condition, and the patient died on January 15. We described a case of non-Hodgkin's lymphoma complicated by hepatic dysfunction, probably induced by CPM, in an elderly patient who died to hepatic failure.

Aged↗
PubMed1992

[Elderly non-Hodgkin's lymphoma presenting with pulmonary squamous cell carcinoma as a complication of chemotherapy for malignant lymphoma].

The authors report a case of pulmonary squamous cell carcinoma which occurred after chemotherapy of non-Hodgkin's lymphoma (NHL). A 76-year-old man, who was admitted to our department because of swelling of cervical lymph nodes, was diagnosed as having NHL (follicular mixed cell lymphoma). He was treated with 11 courses of CHOP therapy. Thereafter, chemotherapy including ifosfamide was carried out for approximately three years. In June, 1991, he was readmitted to our department because of swelling and pain in his left thigh and an abnormal shadow on chest X-ray. Chest CT demonstrated a cavitated shadow (about 5 cm in diameter) with an irregular margin in right S1, which was suggested to be lung cancer or pulmonary infiltration of malignant lymphoma. Bronchoscopy, which was carried out on July 12, showed bloody sputa from the right B1 ramus and markedly reddened mucosa at the orifice of the right upper bronchus. Sputum cytology revealed no malignancy. ACVP-16 chemotherapy including ara-C, CBDCA and VP-16 was initiated on July 14 because of enlarged superficial lymph nodes. On July 18, he fell out of bed and fractured his left femur. He also suffered from respiratory failure. He died of pulmonary haemorrhage on July 26. Autopsy revealed pulmonary squamous cell carcinoma. The occurrence of pulmonary squamous cell carcinoma is rare after the chemotherapy of malignant lymphoma.

Aged↗
PubMed1992

[Hodgkin's disease presenting with fever of unknown origin associated with granulomas of the bone marrow].

A 73-year-old man was admitted to our hospital on April 30, 1990, because of fever persisting for 18 months. Bone marrow puncture and biopsy were performed, because examination on admission revealed an elevated leukocyte count and anemia while his superficial lymph nodes, liver and spleen were not palpable. The results of the bone marrow biopsy revealed evidence of granuloma. Around May 10, the patient developed hepatosplenomegaly and enlargement of left cervical lymph nodes. Based on the results lymph node biopsy, a diagnosis of Hodgkin's disease was made, and CHOP therapy was instituted on May 20. However, the patient developed interstitial pneumonia and died on July 3. This patient's disease was manifested by fever of unknown origin. Bone marrow biopsy revealed granuloma with histiocytes predominating, and the patient subsequently developed lymph node enlargement. His disease was then diagnosed as Hodgkin's disease on the basis of a biopsy. Malignant lymphomas associated with granulomas in the bone marrow, liver or spleen are for the most part found in the advanced stage of the disease. It should be borne in mind, however, that some patients may exhibit granuloma formation in their bone marrow prior to lymph node enlargement or hepatosplenomegaly, as in the present case.

Aged↗
PubMed1992

[Successful interferon-alpha treatment of hepatitis B developing during chemotherapy of malignant lymphoma].

In a 47-year-old male patient a tonsillar swelling was pointed out in May, 1991. Lymph node biopsy revealed that he had malignant lymphoma (diffuse large cell type). He had no hepatic dysfunction on admission, but because of positive hepatitis B (HB) antigen and negative HB antibody, he was diagnosed as an asymptomatic HB carrier. The staging examination showed that he had stage IIA lymphoma. Treatment with the COP-BLAM regimen was initiated on June 8. But the level of serum GOT and GPT increased to 286 IU/l and 392 IU/l, respectively. Serum DNA polymerase also increased to 9492 cpm. Interferon-alpha (3 x 10(6) units daily) was administered intramuscularly from June 8. Serum DNA polymerase decreased to zero on September 2, and his HBe antibody became positive indicating seroconversion. COP-BLAM chemotherapy without prednisolone was initiated from September 9 and complete remission was achieved. He was discharged from our hospital on September 25. It has been frequently reported that asymptomatic HB antigen carriers developed fulminant hepatitis during the course of chemotherapy. Our case suggests that it is necessary to continue chemotherapy in order to attain seroconversion by early use of interferon-alpha, when lymphoma patients display aggravated hepatic dysfunction and increased DNA polymerase levels.

Hepatitis B↗