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Biomedical subjects

K Hirokawa

Publications and source records attributed to K Hirokawa.

At least 55 records · Page 3Linked to original sources
PubMed1999

Immunological enhancement with a low dose of cyclophosphamide in aged mice.

Aged mice treated with a low dose of cyclophosphamide (CY) showed significantly enhanced immune capacity in cellular proliferation and antibody response. In these mice, total cell numbers were increased both in the thymus and spleen, compared to those in non-treated mice. Treatment with a low dose of CY induced apoptosis of thymocytes in the atrophic thymus of the aged mice, being followed by an increase of proliferation of thymocytes and leading to an increase of thymocytes and splenic T cells. Treatment with a high dose of CY also induced apoptosis in the thymus, but suppressed the proliferative capacity, therefore not leading to an enhancement of immune capacity. In young mice, however, CY suppressed immune capacity regardless of the dose. Thymocytes and splenic T cells of young mice were more susceptible to CY than those of old mice and were decreased in number after the treatment with even a low dose of CY.

Aging↗
PubMed1999

Differential age effect of oral administration of an antigen on antibody response: an induction of tolerance in young mice but enhancement of immune response in old mice.

Sheep red blood cells (SRBC) were orally administered to young (4 months old) and old (22 months old) mice, and its effect on the antibody production after systemic immunization was compared between young and old mice. The results showed that the dose-dependent suppression of antibody response (oral tolerance) was observed in young mice which had been previously treated with oral administration of SRBC. On the contrary, the enhancement of antibody production was observed in old mice which had been treated in the same way. The enhanced level of IgG antibody in old mice was higher than that of young mice. The critical age determining either suppression or enhancement of antibody response after the oral administration of the antigen was present between 6.5 and 10.5 months of age. When the oral administration of the antigen was performed in young (3 months old) and middle-aged mice (12 months old), the oral tolerance for young and the enhanced antibody response for middle-aged mice were observed even at 6 months after the treatment. The analysis by in vitro antibody response using T and B cells prepared from young and old mice showed that age-related alteration of T and B cells is responsible for the suppression and the enhancement of antibody response after oral administration of SRBC, respectively.

Administration, Oral↗
PubMed1999

Protection of retrovirus-induced disease by transplantation of bone marrow cells transduced with MuLV env gene via retrovirus vector.

Fv-4 is a mouse gene that dominantly confers resistance to infection by ecotropic murine leukemia virus (MuLV). We have demonstrated previously that bone marrow chimeras in which hematopoietic cells were replaced with cells expressing Fv-4 resistant (Fv-4r) gene product became refractory to Friend leukemia virus (FLV)-induced leukemogenesis. To induce in vivo resistance against retrovirus-induced diseases by retroviral vector-mediated gene transduction, we introduced Fv-4 env gene into bone marrow cells of FLV-susceptible C3H/He (C3H) mice with retroviral vector (pLSF) derived from murine Friend spleen focus forming virus (SFFV) and the cells were transplanted into lethally irradiated C3H mice. After the bone marrow transplantation, Fv-4r gene product was successfully expressed on erythroid and myeloid cells, while lymphoid cells were only weakly expressing Fv-4r gene product. The C3H mice expressing relatively higher amounts of Fv-4r gene product were rendered resistant to FLV-induced erythroleukemia, while mice expressing lower amounts of the Fv-4r gene product were still susceptible. Effective protection of FLV-induced leukemia in these mice suggested that the Fv-4r gene expression by erythroid cells that were the major target of FLV infection might be critical for resisting FLV-induced leukemia. Thus, gene therapy model by transducing Fv-4r env gene using bone marrow transplantation would provide a useful protection model system of retrovirus-induced diseases.

Animals↗
PubMed1999

Age-related alteration of cytokine production profile by T cell subsets in mice: a flow cytometric study.

Spleen cells from young and old C57BL/6 mice were stimulated with a combination of anti-CD3 and anti-CD28 antibodies, and the profile of cytokine production was examined by two different methods; the concentrations of cytokines as measured by ELISA, and identification of cytokine-positive cells by flow cytometry. The ELISA method revealed that IL-2 production by spleen cells after stimulation was significantly lower in the old mice compared to the young mice. while IFN-gamma production was the reverse. The flow cytometric analysis showed that the percentage of IL-2 positive cells in spleen cells after the stimulation was significantly lower in the older mice than in the young mice, and vice versa for the percentage of IFN-gamma-positive cells. Regarding the T cell subsets, CD4+ T cells were a major source of IL-2 in both the young and old mice. IL-2-positive cells in both CD4+ and CD8+ T cells showed a significant decrease with age. On the contrary, CDX T cells were the major source of IFN-gamma. An age-related increase of IFN-gamma positive cells was observed in both CD4+ and CD8+ T cells. CD4 T cells were the major source of IL-4, and the percentage of IL-4-positive CD4+ T cells also increased with age, although the level of IL-4 production was modest in C57BL/6 mice compared with IL-2 and IFN-gamma. Such age-related changes of cytokine production are presumed to play an important role in the alteration of immunological capacity with age.

Aging↗
PubMed1999

Vitamin E enhances the immune functions of young but not old mice under restraint stress.

Young and old C57BL/6 male mice were given a diet containing a high dose of vitamin E (VE treatment) and its effect on the immune system was examined before and after the exposure to restraint stress. The VE treatment per se gave rise to a slight increase of splenic T cells in percentage and a significant enhancement of Con A response of spleen cells in young, but not in old mice. The VE treatment also resulted in the enhancement of production of IL-2 and IFNgamma in young, but not in old mice. Restraint stress led to thymic involution in both young and old mice. This thymic involution was not ameliorated by the VE treatment. Percentage of splenic T cells and their mitogenic response decreased just after the stress, but soon rebounded over the control level. The VE treatment further enhanced the recovery after the stress in young mice, but on the contrary suppressed the recovery in old mice. The results in the present study suggested that the VE treatment was effective in the prevention of immunological decline of young mice before and after the exposure to the stress. On the other hand, such a preventive effect was not observed in old mice that were already in the depressed state of immunological functions.

Aging↗
PubMed1999

Signal pathway of mitogen-induced Ca2+-activated K+ currents in young and aged T-cell clones of C57BL/6 mice.

Signal transduction pathways of mitogenic plant lectin, concanavalin A (Con A)- and ionomycin (INM)-induced (Ca2+-dependent K+ currents (I(Con A) and I(INM)) have been compared in young and aged T-cell clones by using the nystatin perforated patch-clamp whole-cell recording technique. In young T-cell clones, Con A evoked a long-lasting outward current which is mediated by the activation of the Ca2+-dependent K+ channels. The Ca2+ ionophore, INM, evoked a short-lasting Ca2+-dependent outward K+ current (I(INM)). The protein tyrosine kinase (PTK) inhibitor, herbimycin A (3 x 10(-6) M), but not the G protein blocker, pertussis toxin (PTX, 500 ng ml(-1)), completely prevented the I(Con A), but did not affect the I(INM). In aged T-cell clones, Con A fails to evoke any current response, while INM evokes an outward current which is comparable to that in a young T-cell clone. It is concluded that PTK, but not PTX-sensitive G proteins, plays a critical role in mediation of the signal transduction from Con A stimulation to activation of the Ca2+-dependent K+ channels, and that an impairment of the early signal pathway, perhaps the PTK, might be involved in the mechanism of the age-related decline of the proliferative response of T-lymphocytes to mitogenic stimulation.

Animals↗
PubMed1999

Induction of the p16INK4a senescence gene as a new therapeutic strategy for the treatment of rheumatoid arthritis.

Synovial tissue affected by rheumatoid arthritis is characterized by proliferation, which leads to irreversible cartilage and bone destruction. Current and experimental treatments have been aimed mainly at correcting the underlying immune abnormalities, but these treatments often prove ineffective in preventing the invasive destruction. We studied the expression of cyclin-dependent kinase inhibitors in rheumatoid synovial cells as a means of suppressing synovial cell proliferation. Synovial cells derived from hypertrophic synovial tissue readily expressed p16INK4a when they were growth-inhibited. This was not seen in other fibroblasts, including those derived from normal and osteoarthritis-affected synovial tissues. In vivo adenoviral gene therapy with the p16INK4a gene efficiently inhibited the pathology in an animal model of rheumatoid arthritis. Thus, the induction of p16INK4a may provide a new approach to the effective treatment of rheumatoid arthritis.

Adenoviridae↗
PubMed1999

Expression of inducible nitric oxide synthase (NOS) in bone marrow cells of myelodysplastic syndromes.

Nitric oxide (NO) is a biological mediator which is synthesized from L-arginine by a family of nitric oxide synthases (NOS). We have studied the expression of the inducible NOS (iNOS) by bone marrow cells from the patients with myelodysplastic syndromes (MDS) at the mRNA level by RT-PCR assay and at the protein level by immunohistochemical staining using a specific anti-iNOS monoclonal antibody. The iNOS message was present in 92% of bone marrow tissues from MDS patients (11 out of 12) by an examination using RT-PCR. Basically, iNOS message was negative or very weak in control (1/9) and AML (0/7) cases. This was supported by immunohistochemical findings that the iNOS was positive in most of the bone marrow samples from MDS patients (9 out of 12), while bone marrow cells of control (O out of 12) and AML (O out of 5) cases were basically negative. Double immunostaining for CD68 antigen, which is a marker for macrophage lineage cells, and iNOS was performed on MDS bone marrow sections. iNOS was dominantly localized to bone marrow macrophages, although a part of myeloid cells were also positively stained with anti-iNOS antibody in a part of cases. These results indicated that there is some in vivo induction of iNOS expression for local NO production that might be involved in the dysregulation of hematopoiesis in bone marrow of MDS.

Adult↗
PubMed1999

Induction of adult T-cell leukemia-like lymphoproliferative disease and its inhibition by adoptive immunotherapy in T-cell-deficient nude rats inoculated with syngeneic human T-cell leukemia virus type 1-immortalized cells.

Human T-cell leukemia virus type 1 (HTLV-1) has been shown to be the etiologic agent of adult T-cell leukemia (ATL), but the in vivo mechanism by which the virus causes the malignant transformation is largely unknown. In order to investigate the mechanisms of HTLV-1 leukemogenesis, we developed a rat model system in which ATL-like disease was reproducibly observed, following inoculation of various rat HTLV-1-immortalized cell lines. When previously established cell lines, F344-S1 and TARS-1, but not TART-1 or W7TM-1, were inoculated, systemic multiple tumor development was observed in adult nude (nu/nu) rats. FPM1 cells, newly established from a heterozygous (nu/+) rat syngeneic to nu/nu rats, caused transient tumors only at the injection site in adult nu/nu rats, but could progressively grow in newborn nu/nu rats and metastasize in lymph nodes. The derivative cell line (FPM1-V1AX) serially passed through newborn nu/nu rats acquired the potency to grow in adult nu/nu rats. These results indicated that only some with additional changes but not all of the in vitro HTLV-1-immortalized cell lines possessed in vivo tumorigenicity. Using the syngeneic system, we further showed the inhibition of tumor development by transferring splenic T cells from immunized rats, suggesting the involvement of T cells in the regression of tumors. This novel and reproducible nude rat model of human ATL would be useful for investigation of leukemogenesis and antitumor immune responses in HTLV-1 infection.

Adult↗
PubMed1999

[Intraarterial chemotherapy for uterine cervical adenocarcinoma: evaluation of its efficacy as neoadjuvant therapy].

We performed preoperative intraarterial chemotherapy in twenty cases of uterine cervical adenocarcinoma (stage Ib: 2, II: 15, III: 3) and evaluated the efficacy of this therapy. The dosages used were 75-120 mg of CDDP, 10-20 mg of MMC and 30-60 mg of EPIR. These drugs were administered by intraarterial one-shot infusion twice every three weeks. In five cases, complete response (CR) of the primary lesion was confirmed by histologic examination. There were no cases of CR inpatients with well differentiated adenocarcinoma. Stage reduction was achieved in all cases except three. In all but one case, more than 50% volume reduction was recognized on MR images. These results were not significantly different from those in cases of uterine cervical squamous cell carcinoma in which we performed this therapy. Therefore, we concluded that intraarterial chemotherapy is highly effective and should be carried out as neoadjuvant therapy for advanced uterine cervical adenocarcinoma.

Adenocarcinoma↗
PubMed1998

Hypothalamic control of development and aging of the thymus.

Removal of pituitary gland results in atrophy of the thymus. As the pituitary gland is under the control of the hypothalamus, destruction of the anterior portion of the hypothalamus (AHTL) is expected to negatively influence the thymic function. Contrary to our expectation, the thymus became hypertrophic and the serum level of the growth hormone (GH) markedly increased, when the anterior portion of the hypothalamus was widely destroyed in rats at 1 month and over. The results suggested that AHTL removed the cells secreting GHRIH (growth hormone release inhibitory hormone), but not GHRH (growth hormone releasing hormone), leading to increased secretion of GH from pituitary gland and thymic hyperplasia. In other words, the development and aging of thymus appears to be under the balance of the positive (GHRH) and negative (GHRIH) signals of the hypothalamus. It is most likely that the positive signal is high just after the birth and decreases thereafter with a concomitant increase of the negative signal, leading to the onset of thymic atrophy at around puberty.

Aging↗
PubMed1998

Localization of Fas and Fas ligand in bone marrow cells demonstrating myelodysplasia.

Frequent apoptosis in the bone marrow of patients with myelodysplastic syndromes (MDS) was demonstrated on frozen sections using the terminal deoxytransferase (TdT)-mediated dUTP nick end labeling (TUNEL) method. The overall mean percentage of TUNEL-positive cells was about 17% in the bone marrow of MDS, while bone marrow from control cases exhibited a mean of 3.4% (P < 0.001). To elucidate the mechanism of apoptosis in bone marrow cells of MDS, the expression of Fas antigen and Fas ligand (FasL) was examined by RT-PCR and immunohistochemistry. All MDS cases showed expression of Fas mRNA (12/12) and most exhibited an expression of FasL mRNA (10/12) by RT-PCR. Basically, control cases did not show positive signals for Fas and FasL mRNA, however, a very weak band was detected in three cases (3/10) for Fas and in one case (1/10) for FasL mRNA by RT-PCR. Immunohistochemical examination revealed positive staining for Fas (11/12) and FasL (12/12) in the bone marrow of MDS, while all the bone marrow samples from control cases were negative for anti-Fas (0/15) and for anti-FasL (0/15) antibody. Double staining clarified that TUNEL-positive apoptotic cells expressed Fas antigen on the cell surface, although not all Fas-positive cells were TUNEL positive. The Fas-positive cells of MDS bone marrow included hematopoietic cells expressing CD34 antigen, neutrophil elastase, a marker for myeloid series of cells, or glycophorin A, a marker for erythroid cells. However, CD68-positive cells which were macrophage lineage cells, did not express Fas antigen strongly. In contrast, positive staining for FasL was detected in hematopoietic cells and CD68-positive cells in the bone marrow of MDS. These results suggest that the Fas-FasL system plays an important role in inducing apoptosis in the bone marrow of MDS and works in an autocrine (hematopoietic cell-hematopoietic cell interaction) and/or paracrine (hematopoietic cell-stromal cell interaction) manner.

Adult↗
PubMed1998

Pathological characteristics of gastric carcinomas in the very old.

A total of 69 gastric carcinomas of very old people (aged > or = 85) were collected and pathologically analyzed in comparison with those of young to middle-aged (30-39) and elderly (65-69) people, with special attention to their phase. In the very old, almost all (34/35) carcinomas in the early phase belonged to well-differentiated categories. In the advanced phase, half of them (17/34) were classified into poorly differentiated categories when determined from the predominant pattern, but a well-differentiated pattern almost always coexisted in the superficial site. Thus, the gastric carcinomas in the very old may principally develop as well-differentiated carcinomas which then progress to poorly differentiated carcinomas with time, in contrast to those of the young to middle-aged, most of which emerged from the very early phase as poorly differentiated lesions. The gross features of the carcinomas were also in line with these histological observations. The carcinomas of the elderly showed distinct similarity to those of the very old. The results suggest that poorly differentiated carcinomas of the young to middle-aged and the old may be better classified and analyzed separately in view of the generally recognized etiological (e.g., specifically close causal relationship with environmental factors of the intestinal-type carcinoma of the old) and biological (e.g., practically no tendency for hematogenous metastasis of the diffuse-type carcinoma of the young to middle-aged) differences, although in the General Rules for Gastric Cancer Study of Japan, both are placed in the same category, por (por2).

Adenocarcinoma↗
PubMed1998

Expression of VCAM-1 in lymphocytes during the process of apoptosis.

The administration of corticosteroids induced apoptosis of thymocytes in vivo. Among various adhesion molecules examined, vascular cell adhesion molecule-1 (VCAM-1, CD106) was shown to be strongly expressed in these apoptotic cells. Flow cytometric analysis also showed the expression of VCAM-1 in apoptotic thymocytes. An RT-PCR study demonstrated the expression of VCAM-1 mRNA in thymocytes. Splenic lymphocytes and other lymphoid cell lines also expressed VCAM-1 during the process of apoptosis. VCAM-1 mRNA expression was also observed in RT-PCR performed on these cell lines.

Animals↗
PubMed1998

Introduction of an osteopontin gene confers the increase in B1 cell population and the production of anti-DNA autoantibodies.

Osteopontin (OPN) is an Arg-Gly-Asp-containing phosphoprotein that is secreted by activated T cells. The concentration of serum OPN protein is elevated in autoimmune-prone MRL-lpr mice as well as in patients with systemic lupus erythematosus. Previously, it was shown that OPN induces the polyclonal activation of B cells, resulting in the augmented production of immunoglobulin, indicating that OPN plays some role in the development of autoimmune disease. However, the link between OPN and development of autoimmune disease remains unclear. To analyze the role of OPN in immune system and autoimmune diseases, we have generated two kinds of transgenic mice: one carries the immunoglobulin (Ig) enhancer/SV40 promoter and the other carries the cytomegalovirus enhancer/chicken beta-actin (CAG) promoter. In both groups of transgenic mice, the B1 cell population in peritoneal cavity was markedly increased and titer of IgM and IgG3 antibodies in the serum was considerably higher than that in wild-type mice. Most important, the titer of the IgM class of anti-double-stranded DNA antibody was significantly elevated in transgenic mice. These results strongly suggest that OPN may have an important role in the propagation and differentiation of B1 cells and production of autoantibodies.

Animals↗
PubMed1997

Proliferative activity and p53 protein accumulation correlate with early invasive trend, and apoptosis correlates with differentiation grade in oesophageal squamous cell carcinomas.

Using oesophageal squamous cell carcinoma samples of both intramucosal and advanced types, proliferative activity (Ki-67 labelling index), p53 protein accumulation and apoptosis (in situ DNA nick end labelling) were assessed, and the relation of these values to progression or differentiation grade of tumours was analysed. In terms of proliferative activity and the proportion of positive cases with p53 accumulation, a statistically significant difference was demonstrated between intraepithelial carcinomas and intramucosal carcinomas with stromal invasion (17.2% vs 31.7% for the Ki-67 labelling index, and 23.5% vs 67.4% for the proportion of positive cases of p53 accumulation). Values for the latter were almost comparable to those of advanced carcinomas. Immunohistologically, Ki-67 positive, proliferating cells were distributed preferentially in the peripheral fronts of invading nests. Apoptotic cells were observed in the inner areas of the invading nests of the intramucosal carcinomas with stromal invasion and in more advanced lesions, but were rarely observed in the normal epithelium or intraepithelial carcinomas. Apoptotic cells were seen mainly around areas of keratinization, and the apoptotic cell index was higher in well and moderately differentiated types of advanced carcinomas than in the poorly differentiated type (2.59% vs 1.09%). An increase in proliferative activity and an accumulation of p53 protein are associated with the onset of early carcinomatous invasion, while apoptosis is closely linked with the differentiation grade of carcinoma cells.

Antibodies, Monoclonal↗
PubMed1997

Ex vivo phosphorus magnetic resonance spectroscopy on eye bank corneas and corneal metabolic health.

BACKGROUND: Since a potential exists for untoward effects on the cornea from the high magnetic fields and radio-frequency energies, and the further manipulation required for phosphorus-31 magnetic resonance spectroscopy (31P-MRS), we determined the effects of this technology on tissues using paired human corneas (n = 4) meeting criteria acceptable for transplantation. METHODS: Slit-lamp biomicroscopy, pachometry, specular microscopy, and redux fluorophotometry were performed on all corneas. One cornea of each pair was examined (< 30 min) by 31P-MRS. Following 31P-MRS, slit-lamp biomicroscopy, pachometry, and redox fluorophotometry were again performed. RESULTS: Data tabulated included the 31P energy modulus (1.37 +/- 0.28), the ATP/Pi (2.92 +/- 0.59) and SP/Pi (0.76 +/- 0.04) ratios, and the intracorneal pH (7.24 +/- 0.09). CONCLUSION: Since there were no significant differences in slit-lamp biomicroscopy, endothelial density and morphometry, cell counts, and pachometric and redox fluorophotometric measurements between corneas of each pair before and after 31P-MRS analysis, it was concluded that there was no detectable metabolic damage secondary to such analysis. This study suggests that MRS analysis of human eye-bank tissues does not damage the cornea metabolically and may provide a practical evaluation of the health of the cornea at the biochemical level.

Adenosine Triphosphate↗