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Biomedical subjects

N Harada

Publications and source records attributed to N Harada.

At least 397 records · Page 22Linked to original sources
PubMed1994

Autonomic nervous function of hand-arm vibration syndrome patients.

We have investigated the autonomic nervous function of hand-arm vibration syndrome patients using blood chemical analyses and electrophysiological methods. When exposed to whole body cooling, hand-arm vibration syndrome patients showed a significantly greater increase of plasma norepinephrine than the age-matched healthy controls. The patients also exhibited reduced variation of R-R intervals in electrocardiogram during deep breathing. When classifying the subjects according to the Stockholm Workshop scale of VWF, the subjects of stage 3 showed the most remarkable findings followed by the subjects of stage 2. The findings of the stage 3 subjects were also greater than those of diabetes patients. The excess secretion of norepinephrine in blood reveals that the responsiveness of the sympathetic nervous system to cold exposure is enhanced in hand-arm vibration syndrome patients. The R-R interval variation suggests that the basal activity of the parasympathetic nervous system is reduced. We observed that plasma norepinephrine also increased during short-term exposure of hand-arm to vibration and noise exposure potentiated the effect. It seems likely that repeated vibration exposures of the hand-arm system develop the hyperactivity of the sympathetic nervous system.

Arm↗
PubMed1994

[Drug-resistant multiple myeloma with high serum levels of lactate dehydrogenase and neutrophil infiltration in pleural effusion].

A 57-year-old male patient with multiple myeloma showed an aggressive course with characteristic clinical features: rapid progression of plasmacytoma in the thoratic cavity, high serum levels of lactate dehydrogenase (LDH), which is usually not elevated in myeloma patients, and neutrophil infiltration in pleural effusion. Despite treatment with vincristine, doxorubicin and dexamethasone, the tumor mass had become non-responsive to chemotherapy and been increasing in size in correlating with the increase of serum levels of LDH. The patient died of respiratory failure 4 months after treatment. Thus the serum level of LDH is thought to be a useful clinical marker to monitor disease activity as well as other markers such as monoclonal immunoglobulin and beta 2-microglobulin. To investigate the cause of neutrophil infiltration into pleural effusion, we cultured plasma cells obtained from the effusion for 3 days in serum-free medium and examined the activity of neutrophil chemotaxis in the culture supernatant. The results showed chemotactic activity in the supernatant as high as in positive controls stimulated with a chemotactic factor, formyl-methionyl leucyl phenyl-alanine, suggesting that tumor cells produced neutrophil chemotactic factor(s).

Chemotaxis, Leukocyte↗
PubMed1994

Electron microscopic observations of the relationship between peripheral nerve tissue proper and an endoneurial capillary in a dermal lesion of relapsed lepromatous patient.

The origin of relapse in clinically cured leprosy patients and the dissemination of Mycobacterium leprae in such patients are hitherto little understood phenomena. A detailed electron microscopical examination of a small dermal nerve in a lepromatous lesion of a presently relapsed patient was carried out. Our observations showed the presence of M. leprae in Schwann cells, perineurial cells, vacuolar spaces located in axoplasm and elsewhere. The course of a capillary, entering the endoneurium from the epineurium via the perineurium, suggested the possibility of hematogenous spread of M. leprae which had been tucked away in the dermal peripheral nerve. At the time of relapse, bacilli may multiply in the nerve, may enter the bloodstream, and thus disseminate from the nerve into other nerves and other tissues via hematogenous spread.

Humans↗
PubMed1994

Effects of macrophage colony-stimulating factor (M-CSF) on the mobilization of peripheral blood stem cells.

We studied the effects of human urinary macrophage colony-stimulating factor (huM-CSF) on the mobilization of peripheral blood stem cells (PBSC) following cytotoxic chemotherapy in 6 patients with acute leukemia. After complete remission (CR) was achieved, two courses of consolidation chemotherapy consisting of an intermediate dose of cytosine arabinoside were administered to the patients. During a recovery phase after each course of consolidation chemotherapy, two successive cycles of leukapheresis were performed every other day. M-CSF was administered intravenously at a dose of 8 x 10(6) U/day during a recovery phase after the second course of consolidation chemotherapy (cytotoxic plus M-CSF mobilization). There was no significant difference in white blood cell (WBC) or platelet recovery between the first and second cycles, regardless of the administration of M-CSF. Furthermore, between cytotoxic and cytotoxic/M-CSF mobilization, significant differences were not observed in the harvest of mononuclear cells (average 1.43 x 10(8)/kg vs 1.62 x 10(8)/kg), granulocyte/macrophage progenitor cells (CFU-GM) (1.82 x 10(4)/kg vs 3.07 x 10(4)/kg) or erythroid progenitor cells (BFU-E) (2.86 x 10(4)/kg vs 2.66 x 10(4)/kg). Thus M-CSF is not effective for expanding a pool of circulating hematopoietic stem cells when administered at a conventional dose during hematologic recovery following chemotherapy.

Acute Disease↗
PubMed1993

Interleukin-2 receptor gamma chain: a functional component of the interleukin-4 receptor.

The interleukin-2 (IL-2) receptor gamma chain (IL-2R gamma) is an essential component of high- and intermediate-affinity IL-2 receptors. IL-2R gamma was demonstrated to be a component of the IL-4 receptor on the basis of chemical cross-linking data, the ability of IL-2R gamma to augment IL-4 binding affinity, and the requirement for IL-2R gamma in IL-4-mediated phosphorylation of insulin receptor substrate-1. The observation that IL-2R gamma is a functional component of the IL-4 receptor, together with the finding that IL-2R gamma associates with the IL-7 receptor, begins to elucidate why deficiency of this common gamma chain (gamma c) has a profound effect on lymphoid function and development, as seen in X-linked severe combined immunodeficiency.

Animals↗
PubMed1993

Tissue-specific expression of the human aromatase cytochrome P-450 gene by alternative use of multiple exons 1 and promoters, and switching of tissue-specific exons 1 in carcinogenesis.

Extensive screening of aromatase cDNA was carried out in cDNA libraries from various human tissues. The DNA sequences of all the isolated cDNA clones were identical in the region encoded by exons 2-10 of the aromatase gene. However, tissue-specific sequences, which were classified into four groups, were observed in the 5' portions of the clones corresponding to the region encoded by exon 1. All of them were also found in clones isolated from a human genomic library and mapped between exons 1 and 2 of the human aromatase gene reported previously, suggesting the presence of multiple exons 1 and promoters in the gene. Reverse transcription-PCR analyses of aromatase mRNAs in various tissues revealed that aromatase transcripts are tissue-specifically spliced by alternative use of multiple exons 1, although minor forms of the transcripts were also present in each tissue. Aromatase mRNA is spliced from 10 exons in most tissues, but from 9 exons in the prostate and from 10 or 11 exons in the placenta. This suggests that tissue-specific regulation of the aromatase gene in various tissues may be explained by alternative use of multiple exons 1 flanked with tissue-specific promoters. The alternative use of multiple exons 1 for liver transcripts was found to change developmentally. Furthermore, switch from an adipose-specific exon 1 to another type of exon 1 was observed in aromatase transcripts of adipose tissues of three of five breast cancer patients.

Adipose Tissue↗
PubMed1993

Molecular cloning of a cDNA encoding human histidase.

We isolated overlapping cDNA clones encoding human histidase (histidine ammonia-lyase) from a human lambda gt10 library. The cDNA predicted a 657 amino acid protein of 72,651 Da. The human histadase amino acid sequence was 93% conserved with both rat and mouse histidase sequences, including four N-glycosylation consensus sites.

Amino Acid Metabolism, Inborn Errors↗
PubMed1993

Core glycosylation of cytochrome P-450(arom). Evidence for localization of N terminus of microsomal cytochrome P-450 in the lumen.

It was found that cytochrome P-450(arom) purified from human placenta microsomes is glycosylated, and the sugar chain was cleaved with endoglycosidase H (Endo H). The core glycosylation of P-450(arom) was examined with two heterologous expression systems, cultured insect cells and in vitro translation system. The P-450(arom) protein expressed in the insect cells was glycosylated, and the sugar chain was sensitive to Endo H. It was also glycosylated when translated with the wheat germ cell-free system in the presence of rough microsomal membrane, and the sugar chain could be removed by Endo H treatment. Since the P-450(arom) molecule has two potential glycosylation sites (Asn-12 and Asn-180), we replaced each of the 2 asparagine residues with alanine by site-directed mutagenesis and examined the glycosylation of the two mutant proteins in the cell-free system. The core glycosylation did not occur when the Asn-12 residue was mutated, whereas the mutant protein with modified Asn-180 residue was glycosylated. These results demonstrated that the potential glycosylation site (Asn-12) in the N-terminal portion of P-450(arom) is the site of glycosylation. We conclude that the N terminus of P-450(arom) is translocated across the endoplasmic reticulum membrane to be glycosylated at the luminal side.

Amino Acid Sequence↗
PubMed1993

Synergism between androgens and estrogens in the induction of aromatase and its messenger RNA in the brain.

It is established that testosterone (T) increases aromatase activity (AA) in the quail brain and that this induction of AA represents a limiting factor in the activation of male copulatory behavior. This action of T presumably results from an induction of aromatase synthesis since the number of aromatase-immunoreactive (ARO-ir) cells increases and, in parallel, there is an increase in aromatase mRNA as measured by reverse transcriptase-polymerase chain reaction (RT-PCR) technology. The specific role of androgenic and estrogenic metabolites of T in this induction is not yet clear but product-formation assays suggest that both types of compounds synergize to increase AA. The exact role of androgens and estrogens in the induction of aromatase was examined by studying both the aromatase protein by immunocytochemistry and the aromatase mRNA by RT-PCR in castrated quail that had been treated with T or its androgenic metabolite, 5 alpha-dihydrotestosterone (DHT) or its estrogenic metabolite, estradiol-17 beta (E2) or both DHT and E2 simultaneously. A specific quantitative PCR technique using a modified aromatase as internal standard was developed for this purpose. T increased the number of ARO-ir cells in all brain areas and increased the concentration of ARO mRNA in the preoptic area-anterior hypothalamus (POA-aHYP) and in the posterior hypothalamus (pHYP). E2-treated birds had more ARO-ir cells than castrates in the posterior part of the medial preoptic nucleus (POM), in the bed nucleus stria terminalis (BNST) and tuber. Their aromatase mRNA concentration was significantly increased in the POA-aHYP but this effect did not reach significance in the pHYP. DHT by itself had no effect on either the number of ARO-ir cells (all brain regions considered) or the concentration of aromatase mRNA. DHT, however, synergized with E2, both in inducing ARO-ir neurons and in increasing aromatase mRNA concentration. This synergism was shown to be statistically significant in several brain areas. These data demonstrate that both androgens and estrogens regulate aromatase at the pretranslational level. Because the percentage increase in the number of ARO-iR cells was in general very similar to the increase in aromatase mRNA concentration, these data also suggest that these steroids regulate aromatase mostly by changing its mRNA synthesis or catabolism.

Androgens↗
PubMed1993

Expression cloning of a cDNA encoding a novel murine B cell activation marker. Homology to human CD38.

A rat mAb (NIM-R5) has recently been prepared against a novel murine B cell activation marker. We report here isolation of a cDNA (1-19) encoding the B cell-derived protein recognized by NIM-R5 antibody. This cDNA contains an open reading frame that encodes a polypeptide of 304 amino acids with a predicted molecular weight of 34,500. The existence of a 22-amino acid hydrophobic region located 23 amino acids from the amino terminal of the deduced protein, together with four potential N-linked glycosylation sites, characterize the deduced protein encoded by I-19 cDNA as a typical type II transmembrane glycoprotein. Although I-19 cDNA appears to encode a novel murine protein, its nucleotide sequence and deduced amino acid sequence show approximately 70% homology to the previously reported sequence of human CD38, suggesting that I-19 cDNA encodes either the mouse homologue of CD38 or a closely related protein. Northern blot analysis of the expression of this cDNA product in a variety of cell types, together with immunoprecipitation of the recombinant protein expressed in BaF3 cells, indicated that I-19 cDNA encodes not only the epitope recognized by NIM-R5 but also a protein that is indistinguishable biochemically and in terms of distribution from the murine B cell activation marker recognized by NIM-R5 antibody. Chromosomal mapping studies have localized this locus to the proximal region of mouse chromosome 5. We anticipate that the availability of probes for the murine B cell activation marker recognized by NIM-R5, and the recombinant protein itself, will greatly aid efforts to define the role of this molecule in murine B cell development.

ADP-ribosyl Cyclase↗
PubMed1993

Effects of changes in gonadal hormones on the amount of aromatase messenger RNA in mouse brain diencephalon.

Aromatase in brain is known to play a crucial role in development and maintenance of androgen dependent sexual behavior of males. Biochemical studies have shown that the aromatase activity in brain is influenced by androgen. In this study, we measured the aromatase mRNA content of mouse brain quantitatively to gain a deeper insight into this phenomenon. We found that in the diencephalic area it is sexually dimorphic, as reported for aromatase activity. The amount of aromatase mRNA in this area in males was 150% higher than that in females and decreased to the level in females after castration. The content of aromatase mRNA in castrated males was elevated by 2-fold by injection of testosterone and restored to the level observed in intact males. Injection of testosterone also affected the level of aromatase mRNA in normal mice of both sexes, though to lesser extent. On the contrary, injection of estrogen decreased the amount of aromatase mRNA in gonadectomized mice of both sexes. These results show that transcriptional control of the aromatase gene is involved in the mechanism of testosterone to affect sexual behavior.

Animals↗
PubMed1993

Ligand-dependent activation of chimeric receptors with the cytoplasmic domain of the interleukin-3 receptor beta subunit (beta IL3).

beta IL3 (formerly known as AIC2A), a beta subunit of the murine interleukin-3 receptor (IL-3R), is not only required for formation of the high affinity receptor but is also important for signal transduction. To examine the function of beta IL3 in signal transduction, we constructed several chimeric receptors consisting of the intracellular portion of beta IL3 and the extracellular portion of other members of the cytokine receptor superfamily, i.e. the human interleukin-2 receptor beta chain (hIL-2R beta), the human interleukin-4 receptor (hIL-4R), and the murine erythropoietin receptor (mEpoR). These chimeric receptors and normal cytokine receptors were expressed in an IL-3-dependent murine pro-B cell line, Ba/F3, and an IL-2-dependent murine T cell line, CTLL2. Regardless of the origin of the extracellular domain, these chimeric receptors were functional in Ba/F3 cells; they stimulated proliferation and induced tyrosine phosphorylation in response to the cytokine corresponding to the extracellular domain. However, the response of transfectants expressing chimeric receptors was similar to, but not identical with, the response of Ba/F3 cells to mIL-3. We present evidence that the IL-4R and EpoR probably have an additional component which is involved in signal transduction.

Animals↗
PubMed1993

Interleukin-4 (IL-4) induces protein tyrosine phosphorylation of the IL-4 receptor and association of phosphatidylinositol 3-kinase to the IL-4 receptor in a mouse T cell line, HT2.

To study the signal transduction mechanism of interleukin-4 (IL-4), we have examined the effects of IL-4 on protein tyrosine phosphorylation in a mouse IL-2-dependent T cell line, HT2. Mouse IL-4 induces HT2 proliferation in a dose-dependent manner. Western blotting analyses using anti-phosphotyrosine antibody showed that IL-4 induces tyrosine phosphorylation of four proteins (140, 110, 100, and 92 kDa) in a dose-dependent manner. Protein tyrosine phosphorylation was detected within 1 min and reached a plateau approximately at 10 min after IL-4 stimulation. Immunoprecipitation using anti-IL-4 receptor antibody revealed that the 140-kDa tyrosine-phosphorylated protein is the IL-4 receptor (IL-4R) itself. Furthermore, we demonstrate that phosphatidylinositol 3-kinase (PI 3-kinase) activity in immunoprecipitates with anti-IL-4R antibody increases after IL-4 stimulation. These data indicate that IL-4 induces activation of tyrosine kinase and also induces association between IL-4R and PI 3-kinase.

Animals↗
PubMed1993

Hyposmotic activation hyperpolarizes outer hair cells of guinea pig cochlea.

The electrophysiological responses of isolated guinea pig outer hair cells (OHCs) to hyposmotic activation were studied using the whole-cell patch-clamp technique. The cell swelling by hyposmotic activation hyperpolarized OHCs by 6.6 +/- 2.3 mV from the resting membrane potential of -58.5 +/- 5.9 mV (n = 48). This hyperpolarization was associated with an outward current (97.7 +/- 22.2 pA, n = 15). The hyperpolarization was inhibited by 300 microM quinine, 5 mN Ba2+ and increasing the extracellular K+ to 30 mM from 5 mM. In the absence of extracellular Ca2+ (1 mM EGTA), the hyperpolarization during hyposmotic activation was also abolished while the following depolarization was preserved. 50 microM GdCl3, which is known to block stretch-activated non-specific cation channels, inhibited the hyperpolarization reversibly. 50 microM GdCl3 also inhibited [Ca2+]i increase during hyposmotic activation as shown by the calcium-sensitive dye fura-2. Simultaneously, the [Ca2+]i increase and the hyperpolarization during hyposmotic activation could be observed using the combined method of whole-cell patch clamp and fura-2 technique. It is concluded that the cell swelling by hyposmotic activation may activate the stretch-activated non-specific cation channels in the OHCs which allow a Ca2+ influx. In turn, this [Ca2+]i increase leads to an activation of the Ca(2+)-activated K+ channels at the basolateral membrane of OHCs which results finally in a reversible hyperpolarization of OHCs by K+ efflux.

Animals↗