Biomedical subjects

Y Shikama

Publications and source records attributed to Y Shikama.

36 records · Page 2Linked to original sources

PubMed1994

[A case of cervical spondylitis mimicking motor neuron disease].

The patient was a 65-year-old man who had noted mild weakness of the right hand since summer, 1990. In October, 1990, he had fever and developed apparent weakness of the upper extremities. Neurological examination on admission revealed distal dominant muscle weakness and atrophy of the upper extremities with fasciculation. Deep tendon reflexes were diminished in the upper limbs and exaggerated in the lower ones. No sensory disturbance or cerebellar signs were recognized. Laboratory examination of his blood showed leukocytosis and elevated levels of acute reactants. The needle EMG showed a neurogenic pattern. MRI study of the neck disclosed narrowing of the intervertebral space between C7 and Th1 and a low signal intensity of these vertebral bodies on T1 weighted image. Treatment with antibiotics improved his neurological symptoms and the abnormal MRI findings. The present case was diagnosed as having cervical spondylitis. Neurological symptoms and signs associated with cervical spondylitis have been reported to be paraplegia or quadriplegia. Like the present case, however, cervical spondylitis should also be considered as one of the diseases which could show symptoms and signs very similar to those of motor neuron disease.

Aged↗

PubMed1993

Human granulocyte-macrophage colony-stimulating factor receptor signal transduction requires the proximal cytoplasmic domains of the alpha and beta subunits.

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) controls the production, maturation, and function of cells in multiple hematopoietic lineages. These effects are mediated by a cell-surface receptor (GM-R) composed of alpha and beta subunits, each containing 378 and 881 amino acids, respectively. Whereas the alpha subunit exists as several isoforms that bind GM-CSF with low affinity, the beta common subunit (beta c) does not bind GM-CSF itself, but acts as a high-affinity converter for GM-CSF, interleukin-3 (IL-3), and IL-5 receptor alpha subunits. The cytoplasmic region of GM-R alpha consists of a membrane-proximal conserved region shared by the alpha 1 and alpha 2 isoforms and a C-terminal variable region that is divergent between alpha 1 and alpha 2. The cytoplasmic region of beta c contains membrane proximal serine and acidic domains. To investigate the amino acid sequences that influence signal transduction by this receptor complex, we constructed a series of cytoplasmic truncation mutants of the alpha 2 and beta subunits. To study these truncations, we stably transfected the IL-3-dependent murine cell line Ba/F3 with wild-type or mutant cDNAs. We found that the wild-type and mutant alpha subunits conferred similar low-affinity binding sites for human GM-CSF to Ba/F3, and the wild-type or mutant beta subunit converted some of these sites to high-affinity; the cytoplasmic domain of beta was unnecessary for this high-affinity conversion. Proliferation assays showed that the membrane-proximal conserved region of GM-R alpha and the serine-acidic domain of beta c are required for both cell proliferation and ligand-dependent phosphorylation of a 93-kD cytoplasmic protein. We suggest that these regions may represent an important signal transduction motif present in several cytokine receptors.

Amino Acid Sequence↗

PubMed1993

Heparin sulfate-like immunoreactivity in the spinal cord in motor neuron disease.

The spinal cords from eight autopsy cases of sporadic motor neuron disease (MND) and two control cases were immunohistochemically examined using antibodies directed to neurofilament proteins (anti-Nf) and to heparan sulfate (HepSS-1). Variable numbers of spheroids were observed in the anterior horns in the MND cases. In one case of MND, one third to half of the remaining anterior horn cells contained conglomerate inclusions in their perikarya. These pathological structures were not encountered in the control cases. The immunohistochemical study revealed that both anti-Nf and HepSS-1 intensely labelled all spheroids and conglomerate inclusions in the MND cases. The colocalization of heparan sulfate with neurofilamentous accumulation suggests that heparan sulfate is required for the aggregation of neurofilaments, resulting in the formation of spheroids and conglomerate inclusions in MND.

Aged↗

PubMed1993

Thrombopoietic effects of interleukin-6 in long-term administration in mice.

To further investigate the thrombopoietic and adverse effects of interleukin-6 (IL-6), 2 or 10 micrograms/day of recombinant human (rh) IL-6 was administered intraperitoneally (i.p.) to mice for up to 30 days. IL-6 increased platelet count, which plateaued at a level 30 to 40% higher than control after 5 days of treatment. This cytokine also maintained the high platelet count for the duration of treatment. The count exceeded normal levels 7 days after cessation of the 30-day treatment. IL-6 also induced a remarkable increase in the size but not the frequency of megakaryocytes in bone marrow sections. The number of bone marrow colony-forming units megakaryocyte (CFU-MK) and colony-forming units granulocyte-macrophage (CFU-GM) was not augmented by the administration of IL-6 in this protocol, while spleen progenitors were significantly stimulated. Small but significant increases did occur in the number of bone marrow megakaryocytes and CFU-MK, and in the proportion of CFU-MK in the DNA synthetic phase in mice treated with 10 micrograms/day of IL-6 for 30 days. Electron microscopic examination of bone marrow demonstrated that IL-6 remarkably developed the distribution of the demarcation membrane system (DMS) in mice treated for 30 days, with little change in mice treated for 5 days. The administration of 2 micrograms/day for 30 days induced a 2.2-fold increase in fibrinogen. No changes were observed in the hepatic or renal functions. Histologic and immunofluorescence studies on the kidneys revealed no significant changes compared with controls, indicating that proliferation of the glomerular mesangium did not occur. No neutralizing antibodies were detected in mice treated for 30 days. We conclude that the long-term administration of IL-6 in mice stimulates megakaryocyte maturation and platelet production with few adverse effects, and that this cytokine may be a candidate for the treatment of thrombocytopenia in humans.

Animals↗

PubMed1992

Marked increase in cerebrospinal fluid ubiquitin in Creutzfeldt-Jakob disease.

We have established the radioimmunoassay for ubiquitin in the cerebrospinal fluid (CSF) and measured the ubiquitin concentration in CSF from 4 cases of neuropathologically verified Creutzfeldt-Jakob disease (CJD), 10 cases of multi-infarct dementia (MID), 7 cases of senile dementia of Alzheimer type (SDAT), and 18 controls. The normal values were determined to range from 7.3 to 21.0 ng/ml, 14.3 +/- 1.1 ng/ml in the mean +/- S.E.M. The CSF ubiquitin levels in the cases of MID and SDAT were 16.6 +/- 6.4 ng/ml and 21.3 +/- 6.1 ng/ml, respectively. In the cases of CJD, the CSF ubiquitin was markedly increased at the early and middle stages of the disease (230.6 ng/ml in Case 1, 107.6 ng/ml in Case 2, 212.5 ng/ml in Case 3, and 377.0 ng/ml in Case 4) and these gradually decreased as the disease progressed. The measurement of CSF ubiquitin seems useful to make an early diagnosis of CJD.

Aged↗

PubMed1992

Transient effect of erythropoietin on thrombocytopoiesis in vivo in mice.

To assess the thrombopoietic activity of erythropoietin (Epo) in vivo in mice, we consecutively administered recombinant human Epo (rEpo) i.p. to intact and splenectomized mice for varying time intervals. Recombinant human Epo increased platelet counts in a dose-dependent fashion in a short-term trial for 5 days. An 18% +/- 12% increase in platelet counts was observed in intact mice injected with a total of 50 U rEpo over 5 days, whereas an increase of 31% +/- 15% was found in splenectomized mice treated in the same manner. The factor also elicited a significant increase in bone marrow megakaryocytic size of the same magnitude in both groups. The numbers of megakaryocytes and megakaryocytic progenitors in bone marrow were not altered by the treatment. In addition, rEpo induced a dose-related increment in spleen weight. Ultrastructural analysis of spleens in mice injected with rEpo for 5 days revealed no significant increase in sectional platelet counts and in the numbers of vacuolar and platelet-phagocytoid cells when compared with control mice treated with heated rEpo. These findings suggest that Epo has an effect on thrombocytopoiesis, functioning as a late stimulator in short-term administration, they also suggest that its ability is partially masked by splenic pooling by enlarged spleens, giving rise to the discrepancy in platelet counts between and splenectomized mice. However, the induced increases in both parameters, platelet counts and megakaryocytic size, declined after 5 days. Platelet counts returned to normal levels in intact mice 15 days after initiation of the injection, whereas no significant difference in megakaryocytic size was noticed on day 10 compared with controls. The same results came out in splenectomized mice. Anti-human rEpo antibody was not detected in the sera of treated mice in a series of experiments. The splenic weight remained at plateau levels for up to 30 days. Thus, the substantial effects of rEpo on megakaryocytopoiesis and platelet production are transient, neither due to the appearance of the antibody to human rEpo nor the concealment by splenic pooling. The mechanisms of the transient action of Epo on thrombocytopoiesis remain to be further studied.

Animals↗

PubMed1991

Calcitonin gene-related peptide immunoreactivity in familial amyotrophic lateral sclerosis.

The lumbar cords from 3 cases of familial amyotrophic lateral sclerosis (fALS), one case of vincristine neuropathy, and two control cases were examined with an antiserum to calcitonin gene-related peptide (CGRP). The anti-CGRP intensely labelled the spinal posterior horns in all cases. In the anterior horns, several perikarya and cord-like neuritic swellings, mostly axons, were labelled with the antibody in the fALS cases, whereas CGRP-positive structures were extremely rare in the cases other than fALS. It is possible that the accumulation of CGRP in the proximal axonal swellings and perikarya may result from entrapment of CGRP during the anterograde axonal transport, causing loss of, or decrease in, CGRP at the neuromuscular junction and producing weakness and atrophy of the muscles.

Adult↗

PubMed1991

Calcitonin gene-related peptide immunoreactivity in spinal spheroids in motor neuron disease.

The spinal cords from seven autopsy cases of sporadic motor neuron disease (MND) and two controls were immunohistochemically examined using antibodies directed to calcitonin gene-related peptide (CGRP) and to neurofilament proteins (Nf). CGRP immunoreactivity was observed in the posterior horns, especially in the laminae I and II, of all the spinal cords examined. In MND cases, in addition, a considerable number of spheroids in the anterior horns were labelled with the antibody. In some spheroids, their entire area was homogeneously immunostained, whereas in others the immunoreactivity was confined to a focal area(s) within the profile of the spheroids and between these two forms of staining several variations of the staining patterns were seen. The anti-Nf intensely and homogeneously labelled all spheroids and there was no appreciable difference in the Nf-immunoreactive pattern between CGRP-positive and -negative spheroids. It is possible that the accumulation of CGRP in spheroids may result from entrapment of CGRP during the anterograde axonal transport, causing loss of CGRP at the neuromuscular junction and producing weakness and atrophy of the muscles.

Aged↗

PubMed1990

Interleukin-1 beta (IL-1 beta) induces thrombocytosis in mice: possible implication of IL-6.

We administered recombinant human interleukin-1 beta (IL-1 beta), the common mediator of inflammation process, to C57B1/6 male mice (0.5 microgram, every 12 hours over five times) intraperitoneally and consequently induced a remarkable thrombocytosis. Day 1 was designated as the following day of the last injection in the morning. A significant thrombocytosis was observed on days 1 through 5 with a peak on day 2 (162 +/- 9 x 10(4)/mm3) compared with the control mice injected with heated IL-1 beta (101 +/- 11 x 10(4)/mm3). A striking increase in mean size of marrow megakaryocytes was noted on days 1 and 2. The incorporation of 75Se-selenomethionine into circulating platelets as a measure of platelet production was about 2.3 times higher in IL-1 beta-treated mice than in control mice. To determine which factor(s) is responsible for elicited thrombocytosis, the in vitro studies and bioassays for several hematopoietic factors were performed. IL-1 beta by itself did not stimulate megakaryocytopoiesis in vitro, suggesting that the thrombocytosis is attributed to other factor(s) via IL-1 beta stimulation. Serum colony-stimulating factor (CSF) activity after a single IL-1 beta (0.5 microgram) injection, monitored by colony assay with 10% tested serum, peaked at 3 hours. Formed colonies were mostly granulocyte (G) and granulocyte-macrophage (GM)-types, and studies using rabbit anti-mouse GM-CSF serum or using human marrow as target cells showed that the CSF activity of the tested serum consisted of, at least, GM-CSF and G-CSF. Addition of IL-3 concomitantly with the tested serum gave rise to a greater number of megakaryocytic colonies. Serum IL-3, monitored by IL-3-dependent cell line 32D clone 5, and erythropoietin activities were not detected at serum level in IL-1 beta-treated mice. Serum IL-6 assay by IL-6-dependent mouse hybridoma cell line MH-60.BSF2 showed high levels of the tested serum with a peak at 2.5 hours with no detection at 10 hours after the injection. Heated IL-1 beta caused an increase of neither IL-6 nor CSF activities. Our data suggest that the thrombocytosis induced by IL-1 beta is mediated by IL-6 or a combination of IL-6 and other cytokine(s), and that IL-6 may play a regulatory role in platelet production in vivo.

Animals↗

PubMed1990

High incidence of 17p13 chromosomal abnormalities in malignant histiocytosis.

Cytogenetic analyses of three patients during autopsy who had a pathologic diagnosis of malignant histiocytosis and of one patient who was strongly suspected to have malignant histiocytosis because of her clinical and hematologic findings were done. All three patients studied with bone marrow specimens showed polyploidy (3.4-20%). Two of three patients with chromosomal abnormalities showed 17p+ markers with a breakpoint at 17p13. Seven of 22 previously reported malignant histiocytosis patients (32%) with descriptions of detailed whole karyotypes have the 17p+ markers, including two of the authors' patients. Five of seven patients with 17p+ involved 17p13. Although breakpoints at the 17p+ in the remaining two were not described, their karyotypes were shown to possibly involve 17p13. The high incidence of this abnormality is not considered accidental, and this breakpoint is not usual in many other neoplastic disorders. These facts may indicate that 17p13 chromosome abnormality is a specific change of malignant histiocytosis.

Adolescent↗

PubMed1990

Effect of recombinant granulocyte-macrophage colony-stimulating factor on murine thrombocytopoiesis in vitro and in vivo.

To investigate the effect of recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) on murine megakaryocytopoiesis in vitro, the factor was added to both serum-free colony assays and liquid marrow cultures. GM-CSF had a significant megakaryocytic colony-stimulating activity. After 2 hours of preincubation with and without 10 ng/mL rGM-CSF, the percentage of megakaryocyte colony-forming cell (CFU-MK) in DNA synthesis was determined by tritiated-thymidine suicide using colony growth. The reduction of CFU-MK colony numbers in marrow culture was 47.5% +/- 9.9%, 20.9% +/- 5.2% (control), respectively, indicating that the factor affected cell cycle at CFU-MK levels. When acetylcholinesterase (AchE) production was measured fluorometrically after 4 days of liquid culture, rGM-CSF elicited an increase in AchE activity in a dose-dependent fashion. To determine if the hematopoietin acts directly on megakaryocytic differentiation, 2 ng/mL rGM-CSF was added to serum-free cultures of 295 single megakaryocytes isolated from CFU-MK colonies. An increase in size was observed in 65% of cells initially 10 to 20 microns in diameter, 71% of cells 20 to 30 microns, and 40% of cells greater than 30 microns. Conversely, in absence of GM-CSF, 17%, 31%, and 10% of cells in each group increased in diameter. These data suggest that rGM-CSF promotes murine megakaryocytopoiesis in vitro and that the response to the factor is direct. To determine if the factor influences megakaryocytic/thrombocytic lineage in vivo, 1 and 5 micrograms of rGM-CSF were administered intraperitoneally every 12 hours for 6 consecutive days. Although a two- to three-fold increase in peripheral granulocytes was observed, neither megakaryocytic progenitor cells or platelets changed. Histologic analysis of bone marrow megakaryocytes showed no increase in size and number. The in vivo studies demonstrated no effect of GM-CSF on thrombocytopoiesis. The discrepancies between the in vitro and in vivo effects of GM-CSF require additional investigations.

Animals↗

PubMed1990

Isolation of rat megakaryocytes by immunomagnetic beads.

An immunomagnetic procedure was developed to purify rat megakaryocytes to homogeneity from flushed marrow cells. The cells from femurs, tibias, and humeri were initially centrifuged at low speed (800 rpm) to remove platelets and layered over a 1.050 g/cm3 Percoll density gradient. After washing at relatively high speed (1,500 rpm), rabbit anti-rat platelet serum (APS) was added to the cell suspension and incubated for 30 min at 4 degrees C. The cells were washed and subsequently treated with immunomagnetic beads coated with sheep anti-rabbit IgG antibody at room temperature for 10 min. Megakaryocytes were selectively isolated using a magnetic concentrator with a purity of 96.6 +/- 3.9%, recovery of 67.7 +/- 30.8%, and viability of 96.0 +/- 3.2%, although megakaryocytes accounted for 0.11 +/- 0.05% of starting marrow cells. Four to 7 x 10(6) megakaryocytes were obtained from 30 rats with a single population. This quantity provided us a possibility to characterize cytokine receptors. To determine if the nearly purified megakaryocytes were able to response to erythropoietin (Epo), one of purified promoting factors in megakaryocytopoiesis, the cells were incubated with 125I-labeled Epo at 15 degrees C for 90 min in the absence and presence of 100-fold excess unlabeled Epo. Autoradiographic analysis demonstrated the specific silver grains on the megakaryocytes, suggesting the presence of Epo receptors. Scatchard analysis revealed a single class of binding sites. These findings suggest that this method may be useful for megakaryocytic receptor studies of cytokines as well as the physiology or biochemistry of megakaryocytes.

Animals↗

PubMed1989

The role of monokines in granuloma formation in mice: the ability of interleukin 1 and tumor necrosis factor-alpha to induce lung granulomas.

Granulomatous inflammation is associated with many significant human diseases, including tuberculosis, leprosy, sarcoidosis, parasite infection, and berylliosis. Very little is known about the basic mechanism of this type of inflammation. In the present study, we showed that pulmonary granulomas were induced in mice by the intratracheal injection of agarose beads coupled to recombinant interleukin 1 (IL-1) or tumor necrosis factor-alpha (TNF-alpha). Histologically, the bulk of granulomas was composed of macrophages and their derivatives. In contrast, the inflammatory reactions induced by beads coupled to either recombinant IL-2 or murine interferon-gamma were considerably smaller than those induced by beads coupled to monokines. These results suggest that macrophages and monokines such as IL-1 and TNF-alpha, but not T cell-derived lymphokines, play an essential role in granuloma formation.

Animals↗

PubMed1989

Granuloma formation by artificial microparticles in vitro. Macrophages and monokines play a critical role in granuloma formation.

To investigate the basic mechanisms of granuloma formation, in vitro granulomas were induced by culturing murine spleen cells in the presence of artificial microparticles. Large granulomas developed around dextran beads. The lesions were inducible by spleen cells from either normal mice or athymic nude mice. Minimal inflammation was produced around latex beads. The histologic features and time kinetics of granulomas in vitro. Culture supernatants of dextran induced granulomas contained high levels of interleukin-1 (IL-1) activity but not interleukin-2 (IL-2) or interleukin-4 (IL-4) activity. IL-1 activity was correlated with granuloma size. Additionally, granulomas were produced by culturing spleen cells in the presence of agarose beads coupled to recombinant IL-1 or recombinant tumor necrosis factor-alpha (TNF-alpha). Granulomatous lesions also were induced by macrophage-enriched populations in the presence of monokine-coupled beads. Adherent macrophages, but not nonadherent cells, were required for induction of granulomas in vitro. In contrast, very small lesions were seen when spleen cells or adherent cells were cultured in the presence of beads coupled to recombinant IL-2 or recombinant interferon-gamma (IFN-gamma). These results suggest that macrophages and monokines such as IL-1 and TNF-alpha play an essential role in granuloma formation in vitro.

Animals↗

PubMed1989

Interleukin-6 is a potent thrombopoietic factor in vivo in mice.

To determine the biologic activity of interleukin-6 (IL-6) on megakaryocytopoiesis and thrombocytopoiesis in vivo, the cytokine was administered intraperitoneally to mice every 12 hours at varying doses for five days or for varying time intervals, based on the kinetic analysis of IL-6 serum levels indicating the peak of 40 minutes following injection, with no detection at 150 minutes. A dose-response experiment showed that IL-6 increased platelet counts in a dose-dependent fashion at a plateau stimulation level of 5 micrograms. Administration of 5 micrograms of IL-6 reproducibly elevated platelet counts at five days by approximately 50% to 60% of increase. Moreover, a striking increase in megakaryocytic size in response to IL-6 was elicited by the treatment, but no change in megakaryocyte numbers; whereas IL-6 administration did not expand CFU-MK numbers. The in vivo studies in this manner had negligible effects on other hematologic parameters, with the minor exception of monocyte levels. These data show that IL-6 acts on maturational stages in megakaryocytopoiesis and promotes platelet production in vivo in mice, suggesting that IL-6 functions as thrombopoietin.

Animals↗

PubMed1988

Multiple cytokine activities and loss of interleukin 2 inhibitor in synovial fluids of patients with rheumatoid arthritis.

Attempts to detect immune mediators in rheumatoid arthritis synovial fluids (RA-SF) by bioassays have yielded conflicting results, and so we analyzed the immune reactions occurring within rheumatoid joints using monospecific immunoassays for cytokines such as interleukin 1 beta (IL-1 beta), interleukin 2 (IL-2) and gamma interferon (gamma-IFN). Furthermore, we examined the IL-2 inhibitors to clarify the immunoregulatory mechanism in the lesion. SF from active RA contained a significant amount of IL-1 beta and IL-2 but not gamma-IFN. In contrast IL-2 inhibitor activity was depressed in RA-SF regardless of clinical disease activity. Our results suggest that cytokine overproduction and deficiency of inhibitory signals may result in the overactivity of cytokines and the overactivity may participate in the joint lesions of RA.

Antibodies, Monoclonal↗

PubMed1988

Direct evidence for granuloma-inducing activity of interleukin-1. Induction of experimental pulmonary granuloma formation in mice by interleukin-1-coupled beads.

Pulmonary granulomas were induced in BALB/c mice by the intratracheal injection of Sephadex G-50 and latex beads. Very large granulomas developed around Sephadex G-50 beads. Minimal inflammation was produced in mice given latex beads. Aqueous extracts prepared from pulmonary granuloma lesions induced in mice by Sephadex G-50 beads contained high levels of interleukin-1 (IL-1) activity but not interleukin-2 (IL-2) activity. IL-1 activity in the extracts correlated with granuloma size. In a subsequent step, large granulomas were induced by the intratracheal injection of Sepharose 4B beads coupled to fractions of the extracts containing IL-1 activity (ie, granuloma-derived IL-1) prepared from Sephadex G-50-induced granulomatous lungs. In addition, large granulomas were induced by the intratracheal injection of recombinant IL-1-coated Sepharose 4B beads. In contrast, very small granulomas were seen when IL-2-coated or plain Sepharose 4B beads were injected into mice. These results indicate that IL-1 participates in the induction and/or expression of granulomas.

Animals↗

PubMedDate not supplied

Modulation of granuloma formation in vitro by endogenous mediators.

We have reported previously that in vitro granulomas are inducible by culturing murine spleen cells in the presence of artificial microparticles, dextran beads, and that macrophages and macrophage-derived cytokines (monokines) including interleukin 1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) play a critical role in the initiation of bead-induced granulomas in vitro. To investigate regulatory mechanisms of granuloma formation, we examined the modulatory effects of various mediators such as IL-1, TNF-alpha, interferon-gamma (IFN-gamma), IL-4, IL-6, transforming growth factor-beta (TGF-beta), dexamethasone and prostaglandin E2 (PGE2) on the development of lesions, because these mediators are known to play a pivotal role in inflammatory responses. The lesions were suppressed by the addition of dexamethasone, PGE2 or certain T cell-derived lymphokines such as IL-4 and IFN-gamma. These results suggest that suppressive signals are different from granulomatogenic cytokines including IL-1 and TNF-alpha and that granulomas are regulated by multi-factor dependent mechanisms.

Animals↗