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Biomedical subjects

M Okuma

Publications and source records attributed to M Okuma.

At least 199 records · Page 11Linked to original sources
PubMed1991

Phosphorylation of the stress protein hsp27 is an early event in murine myelomonocytic leukemic cell differentiation induced by leukemia inhibitory factor/D-factor.

Leukemia inhibitory factor/D-factor, a potent differentiation-inducing glycoprotein for murine myelomonocytic leukemic M1 cells, rapidly stimulated the phosphorylation of a 27 kDa protein with an isoelectric point of 5.6 in a LIF-sensitive M1-T22 cell line but not in a LIF-resistant M1-D(-) cell line. The increase in phosphorylation was detectable 5 min after LIF treatment and was maximal at 10 min. Heat shock treatment at 44.5 degrees C for 30 min also induced the phosphorylation of the same 27 kDa protein. Although this 27 kDa protein did not become labeled with [35S]-methionine, metabolic labeling experiments using [35S]-cysteine or [3H]-leucine clearly demonstrated that the synthesis of this protein was enhanced after heat shock. These results suggest that the phosphorylated 27 kDa protein is a low molecular weight stress protein and that the protein may play a role at an early stage in the LIF signaling pathway probably linked to macrophagic differentiation.

Animals↗
PubMed1991

Genomic organization of IgH gene compared with the expression of Bcl-2 gene in t(14;18)-positive lymphoma.

In three lymphoma cell lines carrying t(14;18), named FL-18, FL-218, and FL-318, the genomic organization of IgH gene was compared with the expression of bcl-2 gene; the t(14;18) of the FL-18 cells occurred downstream from the major breakpoint cluster region (mbr) of a bcl-2 gene, and that of the FL-218 and FL-318 cells within the mbr. The FL-318 expressed the normal-sized bcl-2 transcript of 8.5-kb mRNA having the noncoding region 3 to the mbr, which was found in the FL-18, and the FL-218 lacking the intact bcl-2 gene did not. This finding suggests that in t(14;18)-positive lymphoma having the breakpoint within the mbr, transcription of the nontranslocated bcl-2 allele is not necessarily silent. In addition, the FL-218 and FL-318 expressed aberrant bcl-2 transcripts and heterogenous IgH transcripts lacking the VH region, and the bcl-2 transcripts each comigrated with parts of the sterile IgH mRNAs. The FL-318, which did not exhibit switch recombination on either IgH allele, contained abundant amounts of l gamma mRNAs, a prerequisite for the recombination into the C gamma locus. One of the I-mRNA species comigrated with the aberrant bcl-2 transcript. The FL-18 and FL-218 lacking the I gamma mRNAs had completed switch recombination of both IgH alleles. This result raises a possibility that deregulated bcl-2 transcription caused by t(14;18) is capable of playing a role in class switch recombination of IgH gene.

DNA Probes↗
PubMed1991

Adenosine deaminase deficiency due to heterozygous abnormality consisting of a deletion of exon 7 and the absence of enzyme mRNA.

An adenosine deaminase (ADA;EC 3.5.4.4)-deficient B lymphoblastoid cell line BADO5 derived from a Japanese patient with severe combined immunodeficiency disease and two B lymphoblastoid cell lines, BAMO5 from his mother and BAFO5 from his father, were characterized. To identify mutations affecting ADA activity, we prepared cDNAs to ADA mRNAs of the BADO5 cell line for nucleotide sequencing. Sequence analysis of one of the BADO5 ADA cDNA clones revealed deletion of exon 7, and one point mutation of base 629 from G to A that did not affect the amino acid sequence. All clones of the BADO5 cell line so far examined showed the absence of exon 7 by Southern blotting analysis. Ribonuclease protection assay with an RNA probe spanning from exon 5 to exon 11 showed that the BADO5 ADA mRNA had a deletion of exon 7, the BAMO5 mRNA had normal length, and the BAFO5 mRNA had two species with a deletion of exon 7 and with normal length. Consequently, the patient's ADA genes resulted from one allele of the BAMO5 ADA gene that did not produce a detectable mRNA, and the other allele of the BAFO5 ADA gene producing an aberrant mRNA without exon 7.

Adenosine Deaminase↗
PubMed1991

Ineffective hemopoiesis in the myelodysplastic syndromes (MDS) as studied by daily in situ observation of colony-cluster formation.

Daily in situ observation of individual proliferating cells was performed to examine ineffective hemopoiesis in vitro. Bone marrow mononuclear cells (BMMNC) from 24 myelodysplastic syndrome (MDS) patients and 12 controls were cultured for granulocyte-macrophage progenitor (CFU-gm) assays using methylcellulose. Individual proliferating cells were mapped at 3 days of culturing and their fates were followed by daily in situ cell counting contained within each cell aggregate until day 8. By retrospective analysis of the daily growth of the cells, a significantly greater proportion of noncolony-forming cells in MDS were found to proliferate initially, but failed to do so thereafter and degenerated in the culture. Cells showing these abnormal growth characteristics apparently contributed to ineffective granulopoiesis. The present method may be useful for clarifying ineffective granulopoiesis.

Adolescent↗
PubMed1991

Photodynamic therapy using pheophorbide-a and Q-switched Nd:YAG laser on implanted human hepatocellular carcinoma.

To evaluate whether administration of pheophorbide-a, a new photosensitizer, followed by use of Q-switched Nd:YAG laser produces a photodynamic reaction, we administered pheophorbide-a to female nude mice (BALB/c-nu) that had been implanted with human hepatocellular carcinoma. Intra-tumoral concentrations of pheophorbide-a were measured by high-performance liquid chromatography. 3 hours after peroral administration of 1 mg/kg body weight, the intra-tumoral concentration was too low to reveal photodynamic effects. Peroral administration of 250 mg/kg body weight, intra-peritoneal administration of 5 mg/kg body weight, and intra-tumoral injection of 200 micrograms yielded 0.24 micrograms/g, 0.83 micrograms/g and 3.68-108 micrograms/g tumor concentrations, respectively. All tumors were irradiated interstitially using a Q-switched Nd:YAG laser at 1064 nm. Only tumors that had been intra-tumorally injected had areas of necrosis larger than those in control tumors. The results suggest that the injection of pheophorbide-a followed by interstitial irradiation using a Q-switched Nd:YAG laser does not induce sufficient photodynamic reaction if the intra-tumoral pheophorbide-a concentration is less than 0.83 micrograms/g tumor tissue, and that photodynamic therapy may be useful if the pheophorbide-a tumor concentration is within the range of 0.83-108 micrograms/g.

Animals↗
PubMed1991

Effects of type-beta 1 transforming growth factor on the proliferation and differentiation of mouse myelomonocytic leukemia cells (M1).

Murine myelomonocytic leukemia M1 cells have been used to examine the effects of type-beta 1 transforming growth factor (TGF-beta 1) on cellular proliferation and differentiation in monocyte-macrophage lineage. TGF-beta 1 inhibited immature M1 cell growth due to a general slowdown of the cell cycle, without arrest at any specific point. Ten nanograms per milliliter TGF-beta 1 completely suppressed phagocytic activity and adhesion to the dish surface and partially inhibited the expression of Fc receptors and vimentin during the differentiation of M1 cells induced by IL-6. IL-6-induced declines in the expression of c-myc mRNA and in the accumulation of G0/G1 cells were also partially blocked by TGF-beta 1. When treated concurrently with IL-6 and TGF-beta 1, approximately 50% of M1 cells were morphologically converted to promonocyte or monocyte-like cells, which did not exhibit the characteristics of mature macrophages. Although pretreatment with TGF-beta 1 also inhibited the IL-6-induced phagocytic activity, this inhibition was reversible. Once TGF-beta 1 was removed from the culture medium after 72 h of incubation with IL-6, the kinetics of differentiation induced by IL-6 were faster in pretreated cells than in nonpretreated cells. TGF-beta 1 appears to inhibit the IL-6 induced conversion of M1 cells at the intermediate stage of monocytic differentiation.

Animals↗
PubMed1991

Dephosphorylation of specific proteins in HL-60 cells by 1 alpha, 25-dihydroxyvitamin D3: possible involvement of cAMP-dependent protein kinase.

Changes of phosphoprotein patterns in HL-60 cells were studied during short exposures to 1 alpha, 25-dihydroxyvitamin D3 [1,25(OH)2D3]. One hundred nanometers 1,25(OH)2D3 dephosphorylated at least three proteins in 6 h: phosphoproteins with molecular weights of 82 kD (pp82), 33 kD (pp33), and 31 kD (pp31). Phosphorylation of pp33 and pp31 was also suppressed by 1 mM dbcAMP, and dephosphorylation of the two protein by 1,25(OH)2D3 was inhibited by 8 microM H-8, an inhibitor of cAMP-dependent protein kinase (PKA). Furthermore, 8 microM H-8 inhibited dephosphorylation of the two proteins when it was added with 1,25(OH)2D3. On the other hand, 10 nM TPA gave no significant change to these two phosphoproteins. These results suggest the possibility that PKA is involved in the early stages of 1,25(OH)2D3-induced HL-60 cell differentiation through specific protein dephosphorylation.

Bucladesine↗
PubMed1991

IA antigen-positive epithelioid cells in experimentally induced granulomatous inflammation.

IA antigens on the cell membrane of inflammatory macrophages and epithelioid cells were investigated with immunoelectron microscopic method during development of granulomas induced by subcutaneous inoculation of 10(7) Mycobacterium lepraemurium into mice with and without hypersensitivity. In C57BL/6N (H-2b) immunogenetic high responder mice 6 weeks after infection majority (87%) of infiltrated cells were IA-positive. Two types of the staining reaction, strong and weak reactivity, were recognized among the positive cells. Strongly IA-positive cells showed lower phagocytosis (0.9/cell section) of mycobacteria than the weakly reacted cells (4.9/cell section). The strongly positive cells underwent morphological differentiation into large epithelioid cells during development of the hypersensitivity-type murine lepromas after 10 or more weeks of infection. Types of granulomas and IA-positive cells in C57BL/6N (nu/+) mice were identical to those found in C57BL/6N. In C57BL/6N (nu/nu) athymic nude mice initial infiltrating cells contained 38% of weakly IA-positive macrophages and a small number (7%) of strongly IA-positive macrophages. But the reactivity was lost later and only 4% of IA-positive cells remained in the granulomas without hypersensitivity. CBA/J (H-2k) low responder mice did not show IA-positive cells in either initial or late stage during the development of nonhypersensitivity-type murine lepromas. We suggest that the presence of IA-positive cells, particularly IA-positive epithelioid cells, in the lesions modulates the course of granulomatous tissue reaction in murine lepromas.

Animals↗
PubMed1991

IL-4 down-regulates IL-2 receptor p75 by accelerating its endocytosis.

We examined the effects of interleukin 4 (IL-4) on the expression of IL-2 receptor p75 (IL-2R p75) or beta chain on various human T cells. IL-4 promptly down-regulated surface IL-2 receptor (IL-2R) p75 in these cells. Although IL-2-induced IL-2R p75 down-regulation was seen more quickly, IL-2 did not contribute to the process of the IL-4-induced decrease of IL-2R p75. Northern blotting revealed that IL-4 did not reduce the expression of IL-2R p75 mRNA. Studies using Pronase E, which digests cell surface IL-2R p75, or brefeldin A, which blocks intracytoplasmic protein transport from endoplasmic reticulum to the Golgi apparatus, suggest that IL-4-induced IL-2R p75 down-regulation is controlled after IL-2R p75 is expressed on the cell surface. We found that IL-4 accelerated the endocytosis of IL-2R p75, which was monitored by [125I]Mik-beta 3 monoclonal antibody that recognizes non-IL-2-binding epitope on IL-2R p75. These findings demonstrate that IL-4 down-regulates IL-2R p75 mainly by accelerating its endocytosis.

Cell Line↗
PubMed1991

Genetic studies on experimental autoimmune gastritis induced by neonatal thymectomy using recombinant inbred strains between a high-incidence strain, BALB/c, and a low-incidence strain, DBA/2.

Thymectomy on day 3 after birth induced autoimmune gastritis (AIG) at the age of 2 months in 51-73% of BALB/c mice, and in only 3-5% of DBA/2 mice. AIG was detected by histological and serological (immunofluorescence staining for detecting anti-parietal cell autoantibody) examination. However, autoantibody was weakly positive in almost all of these DBA/2 mice when measured by ELISA using extract of murine gastric mucosa as the antigen. To investigate genetically the mechanism controlling the incidence of AIG, II recombinant inbred strains established by brother-sister mating of (BALB/c x DBA/2) F2 mice (C x D2 strains) were used. Among 26 markers tested, the Mls-1 locus on BALB/c chromosome 1 and the Hc locus coding a complement component (C5) on BALB/c chromosome 2 were found to be associated with high susceptibility to AIG. However, if one or both of the loci were of DBA/2 origin, mice showed medium or low susceptibility to AIG. For further analysis, F1, F2 and back-cross generations of these two strains were tested, but segregation of a single susceptibility or insusceptibility gene was not obtained. Taken together, it seems probable that two or more genes are involved in the induction mechanism of AIG. We did not detect C5 deposition in AIG lesions, nor complement-dependent cytotoxic antibody to parietal cells in serum from AIG mice. However, injection of irradiated spleen cells of DBA/2 mice into BALB/c mice thymectomized on day 3 augmented the incidence of AIG from 71 to 100%, but not that of oophoritis (33%). A relationship between Mls-1a determinants and the pathogenesis of AIG was further suggested from the fact that V beta 6 TcR-expressing T cells increased in number in AIG-bearing compared with normal BALB/c mice.

Animals↗
PubMed1991

Antibody removal therapy used successfully at delivery of a pregnant patient with Glanzmann's thrombasthenia and multiple anti-platelet antibodies.

A 31-year-old Japanese woman with Glanzmann's thrombasthenia became pregnant voluntarily. She had had transfusions with more than 60 units for severe bleeding. She had multiple antibodies against HLA antigens and platelet glycoprotein IIb/IIIa. No compatible platelets were available. To prevent serious hemorrhage during her delivery, antibody removal therapy was carried out three times. Large molecules including immunoglobulins were removed from more than 3 liters of plasma each time. After the titer of antiplatelet antibodies had decreased in the patient's blood, antihuman globulin-lymphocyte cytotoxicity test compatible platelets were transfused. Her bleeding time improved and delivery was induced successfully despite atonic hemorrhage of about 2,000 g of blood. Her infant had no bleeding problems. This patient is the first with Glanzmann's thrombasthenia to receive antibody removal therapy at delivery.

Adult↗
PubMed1991

Use of ofloxacin in prevention and treatment of secondary infections in hematological malignancies.

We evaluated the effectiveness of ofloxacin (OFX) administered for prophylactic purposes during 77 episodes of neutropenia (less than 500/mm3) in 54 patients with hematological malignancies and to combat infection in 17 patients with both hematological malignancies and secondary infections. The prophylactic effect of OFX was demonstrated by the absence of febrile episodes in 73.3% of patients during the neutropenic phase. Of 16 patients who developed secondary infections, 13 showed good responses with other antibiotics. The overall efficacy rate of OFX in secondary infections was 64.7%. Although 4 patients developed elevated SGOT and SGPT levels and 1 showed an elevated BUN level, OFX was generally well tolerated.

Adolescent↗
PubMed1991

Effects of protein kinase A and calcium/phospholipid-dependent kinase modulators in the process of HL-60 cell differentiation: their opposite effects between HL-60 cell and K-562 cell differentiation.

We have previously shown that HL-60 cells treated with 1 alpha, 25-(OH)2D3 in magnesium-deficient medium are committed to differentiate but do not express differentiation-related phenotypes. In the present study, we demonstrated that Mg2+ deprivation blocked the process of differentiation before the induction of lysozyme mRNA and that the process of HL-60 cell differentiation could be divided into two steps, i.e., a commitment step and a phenotypic expression step. We studied the effects of protein kinase A (PKA) and calcium/phospholipid-dependent protein kinase (PKC) modulators at each step. The results indicated that agonists of PKA enhanced both steps but that N-(2-[methylamino]ethyl-5-isoquinolinesulfonamide inhibited them. On the other hand, 1-oleyl-2-acetylglycerol and 12-O-tetradecanoylphorbol-13-acetate enhanced the commitment step but inhibited that of phenotypic expression. Staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine inhibited the commitment step and enhanced that of phenotypic expression. These results indicate that PKA acts as a positive regulatory signal and that PKC has a dual role in the process of HL-60 cell differentiation, i.e., as a positive regulatory signal in the commitment step and as a negative one in the phenotypic expression step. Recently, we have also shown that in K-562 cell differentiation into erythroid lineage, PKA may serve as a negative regulatory signal in both steps; however, PKC may act dually, namely as a negative regulatory signal in the commitment step and as a positive one in the phenotypic expression step.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗
PubMed1991

[Age-related changes in the rat lens: morphological and morphometrical studies].

Age-related changes in the lenses of 90 Wistar male rats, whose ages ranged from 7 to 26 months, were studied morphologically and morphometrically. Morphological studies were performed using biomicroscopy, light microscopy, scanning electron microscopy and transmission electron microscopy. Early cataract formation was observed biomicroscopically in rats of 19 months of age and the number of cataractous lenses increased with aging. Age-related morphological changes in the lenses were observed before cataract formation and these histological changes showed various forms with aging. Flat preparations of the lens epithelium were examined with a computer-assisted cell-analyzer. The mean cell density decreased and the mean cell area enlarged in both central and germinative zones of the lens epithelium with aging. These results suggest that age-related changes of lens epithelial cells do occur and may be associated with the formation of Wistar rat cataract.

Aging↗
PubMed1991

Relationship between esophageal varices and azygos vein evaluated by cineportography.

The relationship between esophageal varices and the azygos vein, which is generally considered to drain the major part of the variceal blood flow, was evaluated by percutaneous transhepatic cineportography in 35 patients with portal hypertension. We classified the patients into three groups. Those patients in whom most of the variceal blood drained into the azygos vein were designated the azygos-type group (n = 18). Those in whom most of the blood flowed into the brachiocephalic venous system were defined as the cervical-type group (n = 5), and those in whom the varices were drained by both the azygos vein and the brachiocephalic venous system were called the combined-type group (n = 12). Highly developed esophageal varices were recognized endoscopically in all patients in the combined-type and cervical-type groups, whereas some of the patients in the azygos-type group had less well-developed varices. In the azygos-type group, a tendency for the varices to be more severe as their drainage into the azygos vein became more cephalad was noted. Evaluation of the drainage of esophageal varices was considered useful not only for obtaining full comprehension of the significance of the azygos vein but also for assessing the suitability for sclerotherapy. Percutaneous transhepatic cineportography was useful for this purpose because it enables visualization of even the most minute amounts of blood flow.

Adult↗
PubMed1991

[Blood flow and blood oxygen partial pressure of the azygos vein in portal hypertension evaluated by the catheter method].

To evaluate the clinical significance of blood flow in the azygos vein and the oxygen partial pressure in azygos venous blood in portal hypertension, we examined 25 patients with liver cirrhosis, 4 with chronic hepatitis, 4 with idiopathic portal hypertension (IPH) and 16 controls by the continuous thermodilution method and azygos venous blood sampling. The azygos venous flow was significantly higher in the patients with chronic liver diseases than in the controls. There was a significant correlation between azygos venous flow and hepatic venous pressure gradient. In the patients with liver cirrhosis, about one half of the azygos venous flow was assumed to represent upward collateral flow, as the azygos venous flow was 3.4% of cardiac output in the controls, 6.3% in the liver cirrhosis patients, and 5.1% in the IPH patients. Oxygen partial pressure in azygos venous blood was higher in patients with portal hypertension, especially in the IPH patients, which indicates that part of splenic flow drains into the azygos vein.

Azygos Vein↗