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Biomedical subjects

M Harada

Publications and source records attributed to M Harada.

At least 631 records · Page 35Linked to original sources
PubMed1994

Interleukin-1 beta, interleukin-6, epidermal growth factor and transforming growth factor-alpha are elevated in the brain from parkinsonian patients.

Interleukin (IL)-1 beta, IL-6, epidermal growth factor (EGF), and transforming growth factor-alpha (TGF-alpha) were measured for the first time in the brain (caudate nucleus, putamen and cerebral cortex) from control and parkinsonian patients by highly sensitive sandwich enzyme immunoassays. The concentrations of IL-1 beta, IL-6, EGF, and TGF-alpha in the dopaminergic, striatal regions were significantly higher in parkinsonian patients than those in controls, whereas those in the cerebral cortex did not show significant differences between parkinsonian and control subjects. Since these cytokines and growth factors may play important roles as neurotrophic factors in the brain, the present results suggest that they may be produced as compensatory responses in the nigrostriatal dopaminergic regions in Parkinson's disease, and may be related, at least in part, to the process of neurodegeneration in Parkinson's disease.

Aged↗
PubMed1994

Divalent metal ion requirements of a thermostable multimetal beta-galactosidase from Saccharopolyspora rectivirgula.

To understand the roles of metal ions on the catalytic properties and thermostability of the thermostable beta-galactosidase of Saccharopolyspora rectivirgula, a thermophilic actinomycete, we have investigated the binding kinetics and requirements of divalent metal ions by equilibrium dialysis, titration, and metal ion buffer techniques. We found that the monomeric multimetal enzyme (M(r) 136,977) had eight specific binding sites for divalent metal ions. These sites were classified as follows: a very tight (class I) site for Ca2+, three tight (class II) sites consisting of two Ca(2+)-specific sites (class IICa) and one Mn(2+)-specific site (class IIMn; Kd for Mn2+, 2.0 nM), and four loose (class III) sites for Mn2+ (Kd, 1.2 microM) and Mg2+ (Kd, 2 microM). Removal of metal ions bound to class II and III sites of the holoenzyme (Ca3Mn5 species; relative Vmax (Vrel), 100%) by a chelating resin at 4 degrees C yielded a less thermostable Ca1 species (Vrel, 1.7%) with a class I Ca2+ ion, removal of which by a chelating resin at 50 degrees C caused a complete irreversible inactivation of the enzyme. Titration studies revealed that stoichiometric binding of Mn2+ to a class IIMn site of the Ca1 species caused a 33-fold activation whereas binding of Ca2+ to class IICa sites had no effect on enzyme activity. Ca1 species could be also activated 8-fold by heating at 60 degrees C for 20 min, suggesting that the catalytically important class II Mn2+ plays important roles in maintaining the native structure essential for activity. Occupation of class III sites by Mg2+ or Mn2+ was of physiological importance to attain sufficient thermostability by which this extracellular beta-galactosidase remained active for a prolonged time at elevated temperatures as was observed during growth of S. rectivirgula.

Binding Sites↗
PubMed1994

[Transluminal atherectomy for occlusive peripheral vascular disease: preliminary results].

We studied the preliminary results of atherectomy of atherosclerotic lesions involving the lower extremities in 10 patients. Fifteen arterial stenotic lesions, five iliac, eight superficial femoral, one popliteal, and one anterior tibial, were treated. Five lesions were re-stenoses after balloon angioplasty, while the remaining lesions were previously untreated primary stenoses. For atherectomy, over-the-wire atherectomy catheters ranging in size from 7 to 10-F were used. Balloon angioplasty was also performed in cases 3, 6 and 9. Atherectomy was considered a success in all patients based on angiographic and clinical criteria. Complications occurred in three patients: intimal dissection, distal embolism and arterial spasm. In the patients with distal embolism, a surgical approach was required to remove the embolus. The internal elastic lamina or media was resected in 10 lesions on the histopathologic specimens. Although further assessment of complications and long-term results is required, these results suggest that atherectomy is useful for treating occlusive peripheral vascular disease.

Aged↗
PubMed1994

Enhanced production of pituitary adenylate-cyclase-activating polypeptide by 1, N6-dibutyryladenosine 3',5'-monophosphate, phorbol 12-myristate 13-acetate and by the polypeptide itself in human neuroblastoma cells, IMR-32.

We investigated a regulatory mechanism for the production of pituitary adenylate-cyclase-activating polypeptide (PACAP) using the human neuroblastoma cell line, IMR-32. Although immunoreactive (ir-) PACAP38 was produced by these cells, it was not accumulated in the culture medium. To overcome this problem, we cultured the cells in the presence of a biotinylated monoclonal antibody to PACAP38 in order to trap ir-PACAP38 in the medium. Then, the trapped ir-PACAP38 was measured with a two-site enzyme immunoassay based on the biotin-avidin interaction. These studies showed that confluent IMR-32 cells constitutively secreted at least 130 pg/10(6) cells per day of ir-PACAP38. Treatment of the cells with 1 mM 1, N6-dibutyryladenosine 3',5'-monophosphate (Bt2cAMP) or 0.1 microM phorbol 12-myristate 13-acetate stimulated ir-PACAP38 production at almost twice the basal level in IMR-32 cells, and these two reagents additively stimulated ir-PACAP38 production. Northern blot analysis indicated that treatment of the cells with both Bt2cAMP and the phorbol ester increased the intensity of several mRNA bands that hybridized with a cDNA probe for human PACAP precursor. We also found that IMR-32 cells possessed high-affinity type-I PACAP receptors (Kd = 230 pM, binding sites: 8.6 x 10(4) sites/cell), which had a 1000-fold higher affinity for PACAP38 and PACAP27 than for vasoactive intestinal polypeptide. The treatment of IMR-32 cells with PACAP and vasoactive intestinal polypeptide increased intracellular cAMP levels, and also increased ir-PACAP production. Northern blot analysis revealed that PACAP at 10 nM markedly stimulated the expression of a 3.7-kb mRNA band that hybridized with PACAP precursor cDNA. These results indicate that IMR-32 cells produce ir-PACAP38, and that PACAP stimulates the synthesis of PACAP mRNA and peptides by increasing intracellular cAMP. Although it remains to be investigated whether PACAP secreted by IMR-32 cells really acts in an autocrine fashion, the present study provides a useful model for further studies of the biological role of PACAP in neuronal cells that produce PACAP and also respond to PACAP.

Bucladesine↗
PubMed1994

Surface phenotype and Ig heavy-chain gene usage in chronic B-cell leukemias: expression of myelomonocytic surface markers in CD5- chronic B-cell leukemia.

We investigated the surface expression of leukocyte differentiation antigens and the Ig heavy-chain variable region (VH) gene family use in leukemic cells from 26 Japanese patients with chronic B-cell leukemias with special reference to CD5 antigen expression. CD5 was expressed on leukemic cells in 21 of 26 cases (CD5+) but not in 5 cases (CD5-). Myelomonocytic marker, CD13 antigen was expressed on the leukemic cells in all 5 CD5- cases but in none of CD5+ cases. Leukemic cells in CD5- cases also expressed CD11b antigen more frequently than those in CD5+ cases (80% v 11%; P < .01). Another myeloid marker, CD33, was expressed neither on CD5+ nor CD5- leukemic cells. CD22, a restricted B-cell marker, was expressed more frequently on CD5- leukemic cells than on CD5+ leukemic cells (80% v 33%; P < .05). Another restricted B-cell activation marker, CD23, was expressed at similar frequency in both the CD5+ and CD5- groups (67% v 60%). Although CD45RA was expressed on the majority of leukemic B cells, the CD45RA expression level was significantly higher among CD5- cases than CD5+ cases (P < .01). In the analysis of VH gene expressed in chronic B-cell leukemias by polymerase chain reaction amplification, CD5+ cases preferentially used VH4 family members (48%; 10 of 21). CD5- cases, on the other hand, mainly used VH3 family (80%; 4 of 5). Thus, from our present observation of an albeit limited patient population, we have found an association between VH gene family use and CD5 antigen expression in chronic B-cell leukemias. We have also shown the differential expression of myelomonocytic markers in the CD5+ and CD5- chronic B-cell leukemias. These result are in agreement with previous suggestions that CD5 positivity is the hallmark for distinct clinical entity commonly referred to in the literature as chronic lymphocytic leukemia.

Adult↗
PubMed1994

Structure and expression of a gene coding for thermostable alpha-glucosidase with a broad substrate specificity from Bacillus sp. SAM1606.

We cloned an alpha-glucosidase gene from thermophilic Bacillus sp. SAM1606 to overexpress it in Escherichia coli transformants. Deletion of the 5'-noncoding region as well as expression of the alpha-glucosidase gene under the control of the icp promotor of the insecticidal crystal protein gene from Bacillus thuringiensis subsp. sotto enhanced the enzyme productivity to 23.5 U/ml, which was 12,000-fold higher than that obtained by the strain SAM1606. The open reading frame corresponding to the alpha-glucosidase encoded 587 amino acid residues including a residue coded by the initiation codon TTG, and the molecular mass of the alpha-glucosidase from N-terminal serine was calculated to be 68,886 Da. Sequence analysis revealed that the SAM1606 alpha-glucosidase belonged to the alpha-amylase family. The SAM1606 alpha-glucosidase showed extremely high sequence identity (62-65%) to the Bacillus cereus and Bacillus thermoglucosidasius oligo-1,6-glucosidases, which were 72% identical to each other. Sequence identity in the suggested active site regions were essentially the same (80-82%) among these three enzymes. However, the substrate specificity of the SAM1606 alpha-glucosidase was significantly different from those of the oligo-1,6-glucosidases. The thermostability of these three alpha-glucosidases could be correlated with the increase in the number of proline residues, whose occurrence was predicted at beta turns and coils in the enzymes.

Amino Acid Sequence↗
PubMed1994

Significance of hepatocellular proliferation in the development of hepatocellular carcinoma from anti-hepatitis C virus-positive cirrhotic patients.

BACKGROUND: There is a hypothesis explaining the pathogenesis of carcinoma that increased proliferation of tissue cells correlates with the development of carcinoma, presumably by increased rate of random mutations and by promotion. In this study, the significance of hepatocellular proliferation in the development of human hepatocellular carcinoma (HCC) from anti-hepatitis C virus (HCV)-positive cirrhotic patients was studied. METHODS: Twenty-eight Child A cirrhotic patients who were anti-HCV (C-100 antibody) positive were studied. At the beginning of the study, the in vitro uptake of bromodeoxyuridine (BrdU, a thymidine analogue) by hepatocytes in biopsied liver specimens was investigated as labeling indices (LIs), and they were divided into high-DNA synthetic (BrdU LI > or = 1.5%) and low-DNA synthetic (BrdU LI < 1.5%) groups. The patients were then surveyed prospectively with frequent ultrasonography (every 3 months) for the development of HCC for 3 years. RESULTS: The mean BrdU LI plus or minus standard deviation for 14 cirrhotic patients with high-DNA synthesis activity (BrdU LI > or = 1.5%) was 2.7 +/- 0.8%, and this was significantly (P < 0.001) higher than that for 14 cirrhotic patients with low-DNA synthesis activity (BrdU LI < 1.5%, 0.5 +/- 0.3%). Nine of 14 (64.3%) of the cirrhotic patients with high-DNA synthesis activity developed HCC in the 3-year period, in contrast to only 2 of 14 (14.3%) of the cirrhotic patients with low-DNA synthesis activity P < 0.05).

Aged↗
PubMed1994

Tumor necrosis factor-alpha (TNF-alpha) increases both in the brain and in the cerebrospinal fluid from parkinsonian patients.

Tumor necrosis factor-alpha (TNF-alpha), a glial-cell-related factor, was measured for the first time in the brain (striatum) and cerebrospinal fluid (CSF) from control and parkinsonian patients by a sensitive sandwich enzyme immunoassay. The concentrations of TNF-alpha in the brain and CSF were significantly higher in parkinsonian patients than those in controls. Since TNF-alpha is an important signal transducer of the immune system with cytotoxic and stimulator properties, these results suggest that an immune response may occur in the nigrostriatal dopaminergic regions in Parkinson's disease and that TNF-alpha may be related, at least in part, to the neuronal degeneration.

Adult↗
PubMed1994

Tubulovesicular transport of horseradish peroxidase in isolated rat hepatocyte couplets: effects of low temperature, cytochalasin B and bile acids.

The transcytotic vesicular pathway in isolated rat hepatocyte couplets was investigated using horseradish peroxidase. Ten to 20 min after horseradish peroxidase labeling, vesicles and tubules containing horseradish peroxidase were observed to be predominantly around the bile canaliculi. In hepatocytes incubated in a 4 degrees C medium for 10 min after horseradish peroxidase labeling, few horseradish peroxidase-containing structures were observed around the bile canaliculi, and the fine reticular immunofluorescence of microtubules was reduced. Cells treated with cytochalasin B (a microfilament inhibitor) showed a fair number of horseradish peroxidase-containing structures around the markedly dilated bile canaliculi and the distribution of microtubules was preserved. Cells labeled by horseradish peroxidase and then incubated for 10 min in a horseradish peroxidase-free medium containing 50 mumol/L of taurocholic acid, ursodeoxycholic acid or tauroursodeoxycholic acid had more tubular structures containing horseradish peroxidase around the bile canaliculi than control cells, whereas 50 mumol/L of taurochenodeoxycholic acid, taurodeoxycholic acid, dehydrocholic acid and taurodehydrocholic acid each failed to increase the number of tubular structures. These findings show that horseradish peroxidase was transported in hepatocyte couplets from the cell periphery to the bile canalicular front through the tubulovesicular pathway, depending on cytoplasmic microtubules. Cytoplasmic microfilaments appeared to play a minor role in this transport. Several specific bile acids such as taurocholic acid, ursodeoxycholic acid and tauroursodeoxycholic acid each promoted the tubular transformation.

Animals↗
PubMed1994

Production of cytokines by thyroid carcinoma cell lines.

Five cell lines were established from four undifferentiated carcinomas and one squamous cell carcinoma of the thyroid. The levels of several kinds of cytokines were measured in the conditioned media of these cell lines by enzyme-linked immunosorbent assay (ELISA). Interleukin-6 (IL-6) was produced by four of the five cell lines, interleukin-1 alpha (IL-1 alpha) by three cell lines, and granulocyte-colony stimulating factor (G-CSF) by two cell lines. The mRNA of IL-1 alpha or IL-6 was detected by Northern blot analysis in all the cell lines which secreted these cytokines into culture medium. These results suggest that undifferentiated carcinoma and squamous cell carcinoma of the thyroid frequently produce cytokines. Further studies are needed to clarify the possible clinical effects of these cytokines in patients with thyroid carcinoma.

Aged↗
PubMed1994

Histological evaluation of benign prostatic hyperplasia treated by long-term administration of chlormadinone acetate (CMA).

Although the clinical effects of attempted nonsurgical treatment of benign prostatic hyperplasia have been well documented, detailed histological evaluation of the effects of treatment appears to be limited. The effect of long-term administration of an antiandrogen, chlormadinone acetate (CMA), on benign prostatic hyperplasia was evaluated with histological comparison of two biopsy specimens, one before treatment and one after treatment. Secretory epithelium showed obvious regressive changes with occasional basal cell prominence after CMA treatment. Stromal elements, however, did not show any marked changes, except for occasional edematous loosening. Scores of multiple epithelial parameters tended to be correlated with clinical improvement in urinary obstructive symptoms, especially in patients with predominant glandular hyperplasia. These results suggest that long-term administration of the potent antiandrogen CMA to inhibit dihydrotestosterone-receptor binding might be a useful therapeutic maneuver in patients with glandular hyperplasia, without any deterioration of the stromal component.

Aged↗
PubMed1994

Purification and characterization of a Bacillus sp. SAM1606 thermostable alpha-glucosidase with transglucosylation activity.

We purified a novel alpha-glucosidase to homogeneity from an Escherichia coli recombinant transformed with the alpha-glucosidase gene from thermophilic Bacillus sp. SAM1606. The enzyme existed as mono- and multimeric forms of a promoter protein with a relative molecular weight of 64,000 and isoelectric point of 4.6. We isolated a monomeric form of the enzyme and characterized it. The enzyme was unique among the known alpha-glucosidases in both broad substrate specificity and high thermostability. The enzyme hydrolysed a variety of O-alpha-D-glucopyranosides such as nigerose, maltose, isomaltose, sucrose, and trehalose efficiently. The molecular activity (k0) and the Michaelis constant (Km) values at 55 degrees C and pH 6.0 for sucrose were 54.6 s-1 and 5.3 mM, respectively. The optimum pH and temperature for hydrolysis were pH 5.5 and 75 degrees C, respectively. The enzyme exhibited a high transglucosylation activity: it reacted with 1.8 M sucrose at 60 degrees C for 70 h to yield oligosaccharides containing theanderose in a maximum yield of 35% (w/w). High thermostability of the enzyme (stable up to 65 degrees C at pH 7.2 for 10 min) permits the transglucosylation reaction at high temperatures, which would be beneficial for continuous production of oligosaccharides from sucrose.

Amino Acid Sequence↗
PubMed1994

Calcium regulating activity of 26,27-dimethyl analog of 24R,25-dihydroxyvitamin D3.

To determine the possibility that methyl substitution in 26- and 27-positions of 24R,25-dihydroxyvitamin D3 [24,25(OH)2D3] alters activities of the original compound, the effects of 24,25(OH)2D3 on calcium (Ca) regulating activity were compared with those of its methyl analog [24,25(OH)2(CH3)2D3] in addition to 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3]. 24,25(OH)2D3 at 10(-6) M and 24,25(OH)2(CH3)2D3 at 10(-7) M and above significantly stimulated both bone resorption in neonatal mouse calvaria cultures and formation of osteoclast-like multinucleated cells (MNC) in mouse bone marrow cultures. A stimulative effect of 1,25(OH)2D3 on bone resorption and MNC formation was recognized in very low concentrations (10(-11) M and above). Although a potency of 24,25(OH)2(CH3)2D3 in stimulating bone calcium (Ca) mobilization and intestinal Ca transport was higher than that of 24,25(OH)2D3, the potencies of both compounds were similar to that of 1,25(OH)2D3 unlike in vitro experiments. As 1,24R,25-trihydroxy-26,27-dimethylvitamin D3 showed almost the same effect as 24,25(OH)2(CH3)2D3, the dihydroxy form is suggested to be hydroxylated at 1 alpha position and converted to trihydroxy form in vitamin D-deficient rats. From these results, methyl substitution in 26- and 27-position of 24,25(OH)2D3 was found to elevate Ca regulating activity of the original compound. In addition, it is suggested that the basis for a similarity in potency between 1,25(OH)2D3 and 24,25(OH)2D3 or its dimethyl analog in vitamin D-deficient rats is likely the result of 1 alpha-hydroxylation.

24,25-Dihydroxyvitamin D 3↗
PubMed1994

Acanthamoeba-specific human T-cell clones isolated from healthy individuals.

T-cell responses to pathogenic free-living amoebae, Acanthamoeba sp., were analyzed in healthy Japanese individuals. Of 20 healthy subjects, 10 (50%) showed significant proliferative responses of peripheral blood mononuclear cells to the soluble amoebic antigens in vitro. The antigens used were not mitogenic, and no evidence of amoebic superantigens was available. We established human T-cell clones reactive to Acanthamoeba, all of which were CD3- and CD4-positive, CD8-negative, and TCR-alpha beta-positive. We isolated two strains of Acanthamoeba from two patients, one from a patient with meningoencephalitis (CSF strain) and the other from a patient with keratitis (K strain). Of 13 clones, 11 were reactive to the K-strain as well as to the CSF-strain antigen under human leukocyte antigen (HLA)-DR restriction, whereas the other two were specific for the K-strain antigen. All but one clone tested showed TH1-equivalent functions because these cells produced interferon (IFN)-gamma in response to the amoebic antigen but produced no detectable level of interleukin 4 (IL-4). These results suggest that immunocompetent hosts might have acquired protective immunity mediated by Acanthamoeba-specific T-cells during natural sensitization.

Acanthamoeba↗