Search PubMed⌕ Search

Biomedical subjects

N Suzuki

Publications and source records attributed to N Suzuki.

At least 523 records · Page 29Linked to original sources
PubMed1997

Polyphenols in chocolate, which have antioxidant activity, modulate immune functions in humans in vitro.

We studied the effects of antioxidants from chocolate, cacao liquor polyphenol (CLP), on human immune functions in vitro. CLP is an enriched polyphenol fraction purified from cacao liquor that is a major component of chocolate. It has been shown that polyphenols have antioxidant activity, and reactive oxygen species (ROS) are involved in immune responses. CLP inhibited both hydrogen peroxide and superoxide anion, typical ROS, production by phorbol myristate acetate-activated granulocytes. CLP also inhibited menadione-induced production of both hydrogen peroxide and superoxide anion in normal human peripheral blood lymphocytes (PBL). CLP treatment of normal PBL in vitro inhibited mitogen-induced proliferation of T cells and polyclonal Ig production by B cells in a dose-dependent manner. CLP treatment inhibited both IL-2 mRNA expression of and IL-2 secretion by T cells. These results suggest that antioxidant CLP has immunoregulatory effects.

Adult↗
PubMed1997

Cloning and characterization of a novel gene, WS-3, in human chromosome 8p11-p12.

A novel human gene referred to as the WS-3 gene, in the short arm of human chromosome 8, was cloned by a combination of exon trapping, thermal asymmetric interlaced-PCR (TAIL-PCR) and the Marathon-Ready cDNA amplification method. The gene consists of 7 exons separated by 6 introns, and is at the telomere side of the STS marker, D8S1055. The full-length WS-3 gene contains 1052 nucleotides and codes for a protein of 190 amino acids with a calculated mol. wt. of 20,747. Southern blot experiments showed that the WS-3 gene exists as a single copy in the human genome. A protein encoded by the WS-3 gene has an R-G-D (Arg-Gly-Asp) motif in the N-terminal region, which seems to confer adhesive properties to macromolecular proteins like fibronectin. Although WS-3 is a small gene with unknown biological function, its ubiquitous expression in various tissues and organs suggests that the encoded protein is one of the essential components of all organs and tissues.

Amino Acid Sequence↗
PubMed1997

Autoreactive T cell clones from patients with systemic lupus erythematosus support polyclonal autoantibody production.

This work examines the functional properties and TCRbeta gene utilization of 15 autoreactive T cell clones derived from five patients with systemic lupus erythematosus. All these clones proliferated and secreted cytokine when stimulated in vitro by autologous (but not allogenic) B cells. Individual T cell clones used diverse TCRbeta genes and did not show skewing toward the preferential usage of anionically charged receptors. Autoreactive T cell clones supported polyclonal B cell activation, as characterized by the production of anti-DNA, anti-Sjögren syndrome A, and anti-tetanus toxoid (anti-TT) Abs. This T cell help was mediated through the production of immunostimulatory cytokines, especially IL-6. Although stimulation of the autoreactive clones was blocked by anti-HLA class II Abs, the T cell clones did not proliferate, nor did they support polyclonal IgG production by HLA class II-matched normal B cells. Unlike the autoreactive clones, TT-specific clones derived from the same patients provided help selectively to B cells secreting anti-TT Abs. These findings suggest that autoreactive T cells from systemic lupus erythematosus patients are triggered to provide help following cognate interactions with self-peptides presented in the context of HLA class II molecules expressed on autologous B cells regardless of their specificities.

Amino Acid Sequence↗
PubMed1997

Role of endothelin-1 in astrocyte responses after acute brain damage.

We examined the possibility of the involvement of endothelin (ET)-1, a potent vasoactive peptide, in the process of astrocyte proliferation after brain injury. Acute brain damage in rats was induced by cold-injury. Astrocytes changed from a differentiated state to an immature, RC-1-positive state immediately after the injury. In the injured site, the level of ET-1-like immunoreactivity in the tissue was significantly increased on the first postoperative day and was sustained at a high level for 5 days. ET(B) receptor mRNA was markedly but transiently down-regulated only on the first day after the injury. Brain extracts (BE) were prepared from the injured tissues, and their effects on the proliferative characteristics of astrocytes were examined in primary culture of astrocytes. The flat morphology, which was observed in association with cell proliferation, and DNA synthesis of astrocytes were enhanced by treatment with each of the BE from 1 (D1-BE), 3 and 5 days after the injury. A monoclonal antibody that recognizes the C-terminus of rat ET-1 and ET-3 inhibited the DNA synthesis of astrocytes induced by D1-BE. These results provide experimental evidence that ET-1 may participate in the initiation of gliosis in the acute phase of brain damage.

Acute Disease↗
PubMed1997

UV-induced mutations affecting codon 12 of the K-ras gene are suppressed by interferon-alpha in human RSa cells.

K-ras gene sequences mutant at codon 12 were recovered following differential dot-blot hybridization of genomic DNA from human RSa cells up to 12 days after the cells had been irradiated with far-UV (principally 254 nm). By contrast, no mutant codon 12 sequences were recovered from cells which had been treated with 50 IU/ml human interferon (HuIFN)-alpha for 24 h prior to their UV exposure. HuIFN-alpha treatment in combination with anti-HuIFN-alpha antibody did not lead to the loss of mutant sequences. However, culture of interferon-pretreated cells with medium containing the protease inhibitor antipain (0.01 mM) for 6 h immediately after UV irradiation led to the recovery of mutant codon 12 sequences. Thus, while treatment with HuIFN-alpha appeared to prevent any UV-induced mutations affecting codon 12 of the K-ras gene from being recovered, the putative antipain-sensitive protease responsible for this suppressive affect appeared to be significantly affected by the protease inhibitor antipain.

Cell Line↗
PubMed1997

Long-term follow-up study of anterior decompression and fusion for thoracic myelopathy resulting from ossification of the posterior longitudinal ligament.

STUDY DESIGN: This was a retrospective study of the results of anterior decompression and fusion in patients with thoracic myelopathy secondary to ossification of the posterior longitudinal ligament with a minimum follow-up time of 5 years. OBJECTIVES: To clarify the effectiveness and limits of anterior decompression and fusion for thoracic ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Posterior decompression for the surgical management of thoracic ossification of the posterior longitudinal ligament has had an uncertain success record. Anterior decompression and fusion have been considered the treatment of choice however, there are few reports describing the long-term results. METHODS: The participants in this investigation were 33 patients whose cases were followed for an average period of 8 years and 2 months. The factors that were investigated included changes in the Japanese Orthopedic Association score and in recovery rates, postoperative complications, and radiographic findings of bone union and progression of ossification of the posterior longitudinal ligament within the area of anterior decompression. RESULTS: Although the recovery rates were relatively stable from 1-5 years after surgery, the rates declined thereafter. The average recovery rate at the final follow-up visit was 53.2%. Postoperative complications included three cases of deterioration of thoracic myelopathy and four cases of extrapleural cerebrospinal fluid leakage. Except for the one case of deterioration of thoracic myelopathy, the remainder of the complications were transient. CONCLUSIONS: Anterior decompression and fusion is an effective surgical procedure for thoracic ossification of the posterior longitudinal ligament with good, stable, long-term results; when thoracic ossification of the posterior longitudinal ligament was extensive or coincident with ossification of the intraspinal ligament, however, the results were not as predictable.

Adult↗
PubMed1997

Cyclic-AMP-dependent activation of an inter-phylum hybrid histone-kinase complex reconstituted from sea urchin sperm-regulatory subunits and bovine heart catalytic subunits.

A cAMP-dependent histone kinase was purified and characterized from spermatozoa of the sea urchin Hemicentrotus pulcherrimus. The molecular mass of the kinase was estimated to be 178 kDa by native PAGE and 400 kDa by gel chromatography on a Superose 6 HR 10/30 column. The enzyme, composed of two 39-kDa catalytic subunits and two 48-kDa regulatory subunits, phosphorylates the lysine-rich histone subspecies (H1 and H2B) isolated from H. pulcherrimus spermatozoa. We isolated cDNA clones encoding a 39-kDa catalytic subunit and a 48-kDa regulatory subunit of the enzyme. The cDNA clone for the 39-kDa subunit was 3881 bp, and the 352-residue deduced amino acid sequence showed 78% similarity with the catalytic subunit of/mammalian cAMP-dependent protein kinase (PKA). The cDNA for the 48-kDa subunit was 4589 bp and the 368-residue deduced amino acid sequence showed 57% similarity with the regulatory subunit of mammalian PKA, although the N-terminal 77 residues showed poor similarity. The mRNAs encoding both the catalytic subunit (7.5 kb) and the regulatory subunit (4.6 kb) were expressed in testis, ovary and egg. An inter-phylum hybrid enzyme, reconstituted from the regulatory subunit of cAMP-dependent histone kinase of sea urchin sperm and the catalytic subunit of bovine heart PKA, has a cAMP-dependent histone kinase activity. Thus, we suggest that the N-terminal 77-amino-acid residues of the regulatory subunit are not essential for inhibition by the regulatory subunit of the catalytic subunit, and that cAMP-dependent inhibitory activity of the regulatory subunit resides in the sequence between the inhibitory site and the C-terminus.

Amino Acid Sequence↗
PubMed1997

Cloning and characterization of Rep-8 (D8S2298E) in the human chromosome 8p11.2-p12.

A novel human gene referred to as the Rep-8 gene (D8S2298E) was cloned by a combination of exon trapping, thermal asymmetric interlaced-PCR, and screening of a cDNA library. It is located in human chromosome 8p11.2-p12. The gene consists of eight exons and spans about 20 kb between the glutathione S-reductase and the protein phosphatase 2A beta subunit genes. The full-length Rep-8 gene contains 1483 nucleotides and codes for a protein of 270 amino acids. Southern blot experiments showed that the Rep-8 gene exists as a single copy per haploid. With a zoo blot analysis, human Rep-8 DNA hybridized strongly with the monkey DNA, but only weakly with the DNAs of species other than Homo sapiens. Northern blot analysis showed that it is expressed abundantly in the testis and ovary, suggesting that the Rep-8 gene product may play a role in reproduction.

Amino Acid Sequence↗
PubMed1997

Gene expressions of transferred human chromosome 8 in mouse cell lines.

Gene expressions were studied for the human chromosome 8 which were introduced by microcell fusion to three mouse tumor cell lines: A9, mouse melanoma B16F10 and SCVA2 derived from SV40-transformed scid fibroblasts. Nineteen genes in the human chromosome 8 were chosen, and the presence of their transcripts in these cells was examined by RT-PCR. The data showed that most of the human genes were expressed, with a few exceptions: the indoleamine 2, 3-dioxygenase gene was expressed in none of these cell lines, while two other genes, calbindin and neuronal nicotinic acetylcholine receptor subunit (Ach Rbeta3) genes, were not expressed in the A9 and SCVA2 cell lines, respectively, suggesting some cell- or species-specific transcriptional regulations exist. These results show that the mouse cell lines carrying a human chromosome are powerful tools for chromosome-specific cDNA cloning.

Animals↗
PubMed1997

In vivo mechanisms for the inhibition of T lymphocyte activation by long-term therapy with tacrolimus (FK-506): experience in patients with Behçet's disease.

OBJECTIVE: To examine the in vivo mechanisms of suppression of T lymphocyte function in patients with Behçet's disease (BD) undergoing long-term treatment with tacrolimus (FK-506). METHODS: Intracellular proteins were analyzed by immunoprecipitation and Western blotting. Messenger RNA expression was studied by a polymerase chain reaction-based technique. RESULTS: Interleukin-2 production was suppressed in patients treated with tacrolimus. This suppression was found to be due to inhibition of interactions between activated calcineurin (Cn) and nuclear factor of activated T cells (NF-AT), inhibition of cleavage of the autoinhibitory domain of the CnA subunit, and inhibition of heterodimer formation by CnA and CnB subunits, resulting in the absence of NF-AT in nuclei of the T cells. We found that T lymphocytes in some BD patients treated with tacrolimus had reduced amounts of FK-506 binding protein (FKBP) in their cytoplasm. CONCLUSION: Tacrolimus reduces the Cn activity of T cells in vivo by the cumulative effects of several distinct mechanisms. It is plausible that reduced amounts of FKBP may be associated with diminished clinical efficacy in some BD patients receiving prolonged treatment with tacrolimus.

Adult↗
PubMed1997

Modulation of synovial cell function by somatostatin in patients with rheumatoid arthritis.

OBJECTIVE: To elucidate the role of neurologic, endocrine, and immune system interactions in the development of pathologic responses in patients with rheumatoid arthritis (RA), we studied somatostatin (SOM) production and somatostatin receptor (SOMR) expression in RA synovium and its function in patients with RA. METHODS: The effects of SOM on proinflammatory cytokine (interleukin-6 [IL-6] and IL-8) and collagenase production by RA synovial cells were estimated by enzyme-linked immunosorbent assay, and their messenger RNA expression was assessed by reverse transcription-polymerase chain reaction (RT-PCR) using limiting dilutions of the complementary DNA. The expression of SOMR by RA synovial cells was also studied by RT-PCR. Local production of SOM was estimated by RT-PCR and immunohistochemical staining. RESULTS: Physiologic concentrations (approximately 10(-10)M) of SOM inhibited proliferation of RA synovial cells. The production of proinflammatory cytokines and matrix metalloproteinases by RA synovial cells was also modulated by SOM. SOMR subtypes 1 and 2 were expressed on fibroblast-like synovial cells, and the expression of SOMR-2 was up-regulated by proinflammatory cytokine treatment of the synovial cells from patients with RA. RA fibroblast-like cells synthesized SOM by themselves, suggesting that SOM acts as an autocrine regulator of synovial cell function in patients with RA. CONCLUSION: SOM inhibited aberrant synovial cell function in patients with RA, suggesting possible clinical applications of this neuropeptide.

Activating Transcription Factor 1↗
PubMed1997

Erythrocyte magnesium and prostaglandin dynamics in chronic sleep deprivation.

BACKGROUND AND HYPOTHESIS: The mechanism of sudden cardiac death occurring in patients with chronic fatigue is controversial. This study was designed to define a hypothesis that coronary arterial spasm and thrombus formation can occur during chronic fatigue. METHODS: For evaluating the feasibility of coronary arterial spasm, erythrocyte magnesium (Mg) was measured. Blood coagulability was evaluated by the change of prostaglandin concentration. Subjects included 16 healthy male volunteers (mean age 21.6 +/- 2.5 years). Test conditions were as follows: (A) control state: a day following a night of good sleep; (B) temporary sleep deprivation: a day preceded by < 3 h of sleep; (C) chronic sleep deprivation: a day preceded by a month during which sleep lasted < 60% of that in condition (A) above. The erythrocyte Mg concentration was measured by the atomic absorption method. The plasma concentration of thromboxane B2 and 6-keto-prostaglandin F1 alpha were measured in eight subjects by radioimmunoassay method. RESULTS: (1) Mean erythrocyte Mg concentration was significantly less in chronic sleep deprivation (1.1 +/- 0.4 mg/dl) than in the control state (1.8 +/- 0.4 mg/dl, p < 0.01) or in temporary sleep deprivation (1.6 +/- 0.4, p < 0.01). (2) The level of thromboxane B2 was significantly higher during chronic sleep deprivation than under control conditions (104.4 +/- 78.0 vs. 20.4 +/- 9.0 pg/ml, p < 0.05). (3) There were no significant intergroup differences in 6-keto-prostaglandin F1 alpha level. CONCLUSION: These findings could support the hypothesis that coronary arterial spasm and thrombus formation occur in chronic sleep deprivation.

6-Ketoprostaglandin F1 alpha↗
PubMed1997

Abnormal expansion of peripheral gamma delta T cells in patients with neurologic disorders.

The proportions and the variable region usages of peripheral gamma delta T cells were investigated in 205 patients with various neurologic disorders. Flow cytometric analysis was performed with monoclonal antibodies against C delta, V delta 1, V delta 2. V delta 1-J delta 1/J delta 2, and V gamma II (9) epitopes. Further analysis was carried out with reverse transcription-polymerase chain reaction (RT-PCR) using variable region-specific primers. The proportion of gamma delta T cells in 33 patients with cerebral palsy (CP) (mean +/- SD; 11.1 +/- 11.0%) was significantly higher than that in 35 normal controls (5.6 +/- 2.6%) (p < .01). Of 205 patients, persistent gamma delta T cell expansion over 15% was observed in 15 patients (M/F = 13/2). Nine of these 15 were patients with CP. Six of the 9 with CP had neither perinatal nor postnatal events related to the neurologic abnormalities. None of the 9 with CP had active infections or autoimmune disorders that could induce gamma delta T cell expansion. Of the 15, 13 had V gamma II/V delta 2-dominant expansion and 2 showed V delta 1-dominant expansion. Unusual expansions of V delta 4 and V delta 6, which were not usually found in peripheral blood, were detected by RT-PCR in one case with CP and V delta 1-dominant expansion. This study showed subclinical immunologic abnormalities with marked and persistent gamma delta T cell expansion in patients with neurologic disorders, especially CP. These results might indicate the existence of neuroimmunologic disorder(s).

Adolescent↗
PubMed1997

Primary structure and bioactivity of bullfrog calcitonin.

Calcitonin was isolated from the bullfrog, Rana catesbeiana, and the first amino acid sequence of an amphibian calcitonin was determined to be Cys-Ser-Gly-Leu-Ser-Thr-Cys-Ala-Leu-Met-Lys-Leu-Ser-Gln-Asp-Leu-His- Arg-Phe-Asn-Ser-Tyr-Pro-Arg-Thr-Asn-Val-Gly-Ala-Gly-Thr-Pro-NH2. Some portions of this sequence are specific to bullfrog calcitonin, and other portions are similar both to teleost calcitonins and to mammalian calcitonins. Administration of 5 pmol of bullfrog calcitonin to rats revealed a hypocalcemic potency similar to that of salmon calcitonin, at least for the first 3 hr.

Amino Acid Sequence↗
PubMed1997

Successful treatment of blunt trauma involving complete laceration of the pancreas and duodenum in a 7-year-old child: report of a case.

The acute onset of peritoneal signs and shock in a 7-year-old boy who had been hit in the epigastrium by a log-seesaw mandated surgical treatment. Enhanced computed tomography (CT) demonstrated complete laceration of the pancreas as well as duodenal injury, and a duodenoduodenostomy with distal pancreaticogastrostomy was subsequently performed. Temporary external drainage of the stomach and distal pancreas led to an uneventful recovery in the early postoperative period. Although the patient's postoperative development was appropriate for his age, the orifice of the distal pancreas spontaneously closed 2.5 years following surgery. We present this report to stress the fact that every effort should be made to preserve the pancreas following abdominal injury in children.

Child↗
PubMed1997

Immunological suppression after surgery in scoliosis patients.

This is a prospective study to analyze the postoperative immunological changes in scoliosis surgery. Twenty-eight patients who underwent Harrington instrumentation were analyzed. Seven patients who underwent arthroscopic surgery were analyzed as a control group. The objective of this study is to determine whether surgery and surgical stress (minor versus major surgery) changed the immune capability of patients as indicated by the ratio of lymphocyte cell types and interferon induction. Pre- and postoperative blood from scoliosis and knee arthroscopy patients was analyzed at various times using antisera and two-color flow cytometry with monoclonal antibodies. Both scoliosis and knee arthroscopy patients had a postoperative decrease in the population of B-lymphocytes (Leu 12+) and a transient increase in the natural killer cells (Leu 4-/Leu 19+) and the cytotoxic T-lymphocytes (Leu 2a++/Leu 15-). These changes were significantly greater in the scoliosis patients, who also experienced a prolonged decrease in the inducer T-lymphocytes (Leu 8+/Leu 3a+) for 3 weeks following surgery. Production of interferon-alpha and interferon-gamma by lymphocytes was suppressed postoperatively and returned to preoperative levels within 3 weeks. Immunological depressive changes occurred postoperatively and lasted at least 1 week. These effects are more pronounced with longer surgeries, suggesting greater postoperative vigilance for infections in these cases.

Adolescent↗
PubMed1997

Analysis of helicase gene mutations in Japanese Werner's syndrome patients.

The profile of helicase gene mutations was studied in 89 Japanese Werner's syndrome (WRN) patients by examining the previously described mutations 1-4 as well as a new mutation found during this study, designated mutation 5. Of 178 chromosomes (89 patients), 89 chromosomes (50%) had mutation 4, 11 (6.2%) chromosomes had mutation 1, and two chromosomes (1.1%) contained mutation 5. Mutations 2 and 3 were not observed in this patient population. The remaining 76 (42.7%) chromosomes had none of these mutations. A significant fraction of all patients (22 total patients, 24.7%) appear to be compound heterozygotes, including those carrying mutations of both types 1 and 4. The genotypes analysis of the markers surrounding the. WRN helicase gene strongly suggests that most of the chromosomes carrying either mutation 1 or 4 were derived from two single founders.

DNA Helicases↗