Biomedical subjects

T Ohtsuki

Publications and source records attributed to T Ohtsuki.

At least 19 recordsLinked to original sources

PubMed1992

Influence of oxidative stress on induced tolerance to ischemia in gerbil hippocampal neurons.

We investigated whether reversible oxidative stress induced by the administration of the superoxide dismutase inhibitor, diethyldithiocarbamate, could induce tolerance to subsequent cerebral ischemia in gerbil hippocampal neurons. Mature male gerbils received intraperitoneal injections of diethyldithiocarbamate (1.0 g/kg), which led to reduced superoxide dismutase activity and increases in thiobarbituric acid-reactive substance in the brain. Cerebral ischemia was produced by occluding the bilateral common carotid arteries for 5 min, either 2 or 4 days after diethyldithiocarbamate injection. One week after ischemia, samples from each brain were stained with hematoxylin-eosin to evaluate ischemic neuronal damage in the hippocampal CA1 sector. Diethyldithiocarbamate treatment 4 days before ischemia had significant protective effects against cerebral ischemia, while diethyldithiocarbamate 2-day pretreatment and vehicle treatment failed to show neuroprotection. Biochemical examinations showed a clear induction of heat shock protein 72 and a significant increase in manganese-containing superoxide dismutase in the hippocampus in animals treated with diethyldithiocarbamate 4 days prior to ischemia. These results suggested that the oxidative stress caused by diethyldithiocarbamate could induced tolerance to ischemia in the gerbil brain, and that the increase in the biosynthesis of manganese-containing superoxide dismutase and heat shock protein 72 could provide a biochemical explanation of the tolerance induced under these conditions.

Animals↗

PubMed1992

A human osteoblastic cell line, MG-63, produces two molecular types of macrophage-colony-stimulating factor.

A human osteoblastic cell line, MG-63, mouse primary osteoblasts, and a mouse osteoblastic cell line, MC3T3-E1, were shown to produce macrophage-colony-stimulating factor (M-CSF) by bone-marrow-cell colony assay, using a specific neutralizing antibody for M-CSF. Immunoblot analysis of M-CSF, produced by MG-63 cells, revealed the presence of a higher-molecular-weight species of M-CSF, in addition to the 85-kDa M-CSF. The higher-molecular-weight species had a high affinity to the DEAE-Sephacel column and was sensitive to chondroitinase ABC and AC. These physico-chemical profiles were wholly compatible with those of the proteoglycan form of M-CSF (PG-M-CSF), which was recently identified by our group in the conditioned medium of Chinese hamster ovary cells transfected with the 4.0-kb cDNA of the M-CSF gene. Conditioned medium of MG-63 cells was fractionated by DEAE-Sephacel column chromatography, and the M-CSF of each fraction was measured by both enzyme-linked immunosorbent assay and bone-marrow-cell colony assay. The fractions eluted by 0.3-0.6 M NaCl, which were shown to contain only PG-M-CSF on immunoblot analysis, also have macrophage-colony-stimulating activity.

Animals↗

PubMed1992

Biological activity of a proteoglycan form of macrophage colony-stimulating factor and its binding to type V collagen.

Two different types of macrophage colony-stimulating factors (M-CSF) were found, one with an apparent molecular mass of 85 kDa and the other greater than 200 kDa. The high molecular mass M-CSF was identified as a proteoglycan carrying chondroitin sulfate glycosaminoglycan and was designated as the proteoglycan form of M-CSF (PG-M-CSF). In this study, we compared the biological activity of the 85-kDa M-CSF and PG-M-CSF and examined the binding properties of these two M-CSF to certain extracellular matrix proteins, i.e. types I-V collagen and fibronectin, using a modified enzyme-linked immunosorbent assay. PG-M-CSF was capable of supporting the formation of murine macrophage colonies, and pretreatment of PG-M-CSF with chondroitinase AC, which degrades chondroitin sulfate, did not alter its colony-stimulating activity. The specific activity of PG-M-CSF was similar to that of the 85-kDa M-CSF. The 85-kDa M-CSF had no apparent affinity for the extracellular matrix proteins examined, whereas PG-M-CSF had an appreciable binding capacity to type V collagen, but did not bind to types I, II, III, and IV collagen or to fibronectin. Pretreatment of PG-M-CSF with chondroitinase AC completely abolished the binding of the species to type V collagen. Addition of exogenous chondroitin sulfate inhibited the binding of PG-M-CSF to type V collagen in a dose-dependent manner. These data indicated that the interaction between PG-M-CSF and type V collagen was mediated by the chondroitin sulfate chain of PG-M-CSF. PG-M-CSF bound to type V collagen could stimulate the proliferation of bone marrow macrophages, indicating that the matrix protein-bound PG-M-CSF retained its biological activity. This interaction between PG-M-CSF and type V collagen implies that the role of PG-M-CSF may be distinct from that of 85-kDa M-CSF.

Animals↗

PubMed1992

An aromatase-associated cytoplasmic inclusion, the "stigmoid body," in the rat brain: I. Distribution in the forebrain.

An aromatase-containing neural system was examined in the rat forebrain, using a polyclonal antibody against aromatase-associated human placental antigen X-P2 (hPAX-P2). Numerous dot-like structures, which we have called stigmoid bodies, were immunostained in the preoptico-hypothalamic region, the bed nucleus of the stria terminalis, the medial amygdala, the arcuate nucleus, the subfornical organ, and the area extending from the hypothalamic area to the central gray through the medial forebrain bundle and the periventricular fiber system of the posterior diencephalon. The stigmoid bodies were always found as inclusions in the neuronal cytoplasm. Their diameter was usually 1-3 microns, but exceptionally large forms, over 3 microns, were found in some brain regions, including the area extending from the median preoptic nucleus surrounding the organosum vasculosum laminae terminalis to the anterior medial preoptic nucleus, the periventricular nucleus of the preoptic area, and some parts of the medial preoptic nucleus. Most of these nuclei show sexual dimorphism. The distribution pattern of the hPAX-P2 immunoreactive stigmoid bodies agreed well with that of aromatase activity previously reported in many biochemical studies. Brain regions where the stigmoid bodies were prominent largely coincide with steroid binding locations common to both androgen and estrogen, or regions where both sex steroid receptors are present. Although it still remains to be determined whether aromatase is localized within these stigmoid bodies, it appears likely that they are closely associated with the function of sex steroids at their target sites in the brain.

Animals↗

PubMed1992

Identification of a high molecular weight macrophage colony-stimulating factor as a glycosaminoglycan-containing species.

Chinese hamster ovary cells transfected with a 4.0-kilobase macrophage colony-stimulating factor (M-CSF) cDNA express two different M-CSF species; one has an apparent molecular weight of 85,000 and is identified as a homodimer of a 43-kDa subunit, and the other has an indeterminate structure greater than 200 kDa. In this study, we investigated the structure of the high molecular weight M-CSF by immunochemical procedures. The high molecular weight M-CSF was easily purified, since it bound tightly to DEAE-Sephacel and eluted at a characteristically high salt concentration. The high molecular weight M-CSF migrated as a diffuse band of over than 200,000 on nonreducing sodium dodecyl sulfate-polyacrylamide gels. Analysis of the same samples under reducing conditions revealed that the larger species consisted of a heteromer of the 43- and 150-200-kDa M-CSF subunits. Digestion of the 150-200-kDa M-CSF subunit with chondroitinase, which degrades the chondroitin sulfate glycosaminoglycan chain, yielded a 100 kDa band. This species was secreted instead of 150-200-kDa species when the cells were cultured in the presence of beta-D-xyloside, which inhibits the elongation of the chondroitin sulfate glycosaminoglycan chain in proteoglycans, providing additional evidence for the existence of a chondroitin sulfate chain in the 150-200-kDa M-CSF subunit. Removal of O- and N-linked carbohydrate from the 150-200-kDa subunit yielded a polypeptide chain with a larger molecular mass (approximately 45 kDa) than that of the 43-kDa subunit (approximately 25 kDa). Collectively, these results indicate that the 150-200-kDa M-CSF subunit is a proteoglycan with a core protein that may be an alternatively processed form of M-CSF.

Animals↗

PubMed1992

Elevated neutrophil function in chronic neutrophilic leukemia.

A 65-year-old man with marked leukocytosis was admitted for diagnosis and treatment. His peripheral blood leukocyte count was 37,500/microliters and the leukocytes consisted of mature neutrophil-like cells. A high neutrophil alkaline phosphatase score and a normal bone marrow cell karyotype suggested that the patient had chronic neutrophilic leukemia rather than chronic myeloid leukemia. Several neutrophil functions, such as superoxide production, nitroblue tetrazolium reduction activity, and phagocytosis, were elevated. These data and the morphological features (toxic granules and Döhle bodies) indicated that the patient's neutrophils were in an activated stage.

Aged↗

PubMed1992

The characteristics of blood-brain barrier in three different conditions--infarction, selective neuronal death and selective loss of presynaptic terminals--following cerebral ischemia.

We investigated the extravasation of serum albumin using immunohistochemistry in three different conditions, i.e., infarction, selective neuronal death and selective loss of presynaptic terminals following cerebral ischemia in gerbils. In selective neuronal death, which is typically found in the CA1 neurons of the hippocampus after 5-min bilateral cerebral ischemia, selective damage of postsynaptic components with intact presynaptic sites was demonstrated by immunohistochemical examination for microtubule-associated protein 2 and synapsin I, and albumin extravasation did not become apparent before postsynaptic structures were destroyed. In cerebral infarction, which was consistently observed in the thalamus after 15-min forebrain ischemia, massive albumin extravasation was visible early after ischemia due probably to the ischemic endothelial necrosis. In selective loss of presynaptic terminals, which was detected at the molecular layer of the dentate gyrus in the contralateral, nonischemic hippocampus after unilateral cerebral ischemia, immunoreaction for albumin was not visualized. Since endothelium and glial cells were intact in morphological aspects in selective damage of both pre- and postsynaptic sites, it was thought that extravasation was facilitated by the stimulation of endothelial cells and glial cells with unknown factors that were induced by the destruction of post- but not presynaptic elements.

Albumins↗

PubMed1992

Recombinant human superoxide dismutase can attenuate ischemic neuronal damage in gerbils.

The effects of recombinant human superoxide dismutase (r-hSOD) on ischemic neuronal injury were examined. Cerebral ischemia was produced in Mongolian gerbils by occluding bilateral common carotid arteries for 5 min. Preischemic treatment with r-hSOD clearly reduced hippocampal neuronal damages while postischemic treatment did not. This result suggests that oxygen free radicals play an important role in selective vulnerability to ischemia and r-hSOD has a potential clinical usefulness against cerebral ischemia.

Analysis of Variance↗

PubMed1992

The synapsin I brain distribution in ischemia.

We examined the distribution of synapsin I in the gerbil brain and investigated ischemic damage of presynaptic terminals immunohistochemically by using this protein as a marker protein of synaptic vesicles. The reaction for synapsin I in normal gerbil brain is exclusively localized in the neuropil, and other brain structures such as neuronal soma, dendrites, axon bundles, glia and endothelial cells exhibited little immunoreactivity. In a reproducible gerbil model of unilateral cerebral ischemia, ischemic loss of synapsin I immunoreactivity in the affected hemisphere was confined to the area exhibiting overt infarction, where the breakdown of this protein was also confirmed by the immunoblot analysis, and noted much later than that of microtubule-associated protein 2 immunoreactivity, which was demonstrated in neuronal soma and dendrites. In the non-affected hemisphere, selective damage of presynaptic terminals due to Wallerian degeneration and subsequently occurring resynaptogenesis at the molecular layer of the dentate gyrus were clearly demonstrated as a loss and recovery of immunoreaction for synapsin I, respectively. In a gerbil model of bilateral cerebral ischemia, immunoreaction for synapsin I was persistently preserved after seven days to two months recirculation following a brief period of global forebrain ischemia in the CA1 region of the hippocampus, where delayed neuronal death was consistently observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Granulocyte colony-stimulating factor-producing malignant lymphoma.

A 71-year-old woman with leukocytosis was admitted for treatment of malignant lymphoma. During the clinical course, neutrophilia of unknown origin occurred in parallel with the progression of the malignant lymphoma. The supernatant of lymphoma tissue culture contained a high titer of granulocyte colony-stimulating factor (G-CSF), and lymphoma cells were positive when immunohistochemically stained by anti-G-CSF antibody. Western blot analysis and mouse colony assay of the supernatant also confirmed that the lymphoma produced G-CSF.

Aged↗

PubMed1992

[Malignant lymphoma with subdural effusion].

A 64-year-old woman was admitted for treatment of malignant lymphoma involving the pharynx and abdomen. Lymphoma disappeared after chemotherapy and radiotherapy, but she had central nervous system symptoms; euphorism, left facial nerve palsy, right hemiplesia, and disturbance of micturition. Magnetic resonance imaging (MRI) revealed a diffuse dural thickening and a subdural fluid retention. The subdural fluid was determined to be an exudate, and a biopsy of the dura mater revealed a normal dura and a fibrin clot containing lymphoma cells and neutrophils. MRI can be very useful to detect the meningeal involvement of malignant lymphoma.

Female↗

PubMed1992

[A case of primary malignant lymphoma of the uterine body].

A 70-year-old female was found to have class V cytology on an endometrial smear, and a histological diagnosis of malignant lymphoma was made by endometrial biopsy. The pathological diagnosis was malignant lymphoma, diffuse large cell-type according to the Working Formulation classification. Immunohistochemical staining showed lymphoma cells to be positive for CD 20 (B 1), indicating B cell lineage. Two cervical lymph nodes were palpable, and swelling of a para-aortic lymph node was also found by abdominal CT scan. The clinical stage was determined to be III according to the Ann Arbor classification. After three courses of CHOP chemotherapy, lymphoma cells could no longer be detected by endometrial biopsy, and the para-aortic and cervical lymphadenopathy also disappeared. Primary malignant lymphoma of the uterus, especially of the uterine body, is very rare. Only eight cases of primary malignant lymphoma of the uterine body were reported in the literature. The cell lineage was decided in only one case, which was B cell type.

Aged↗

PubMed1992

Serial changes of the serum macrophage colony-stimulating factor level after cytoreductive chemotherapy.

To investigate the physiologic role of macrophage colony-stimulating factor (M-CSF) in hematological recovery from bone marrow hypoplasia, we used an enzyme-linked immunosorbent assay to measure serial changes of the serum M-CSF level during 25 intensification chemotherapy courses given to seven patients with acute non-lymphocytic leukemia who were in complete remission. Three M-CSF peaks were observed during therapy: the first peak was during or just after chemotherapy, the second peak was around the leukocyte nadir, and the third peak coincided with a rapid increase in the monocyte count. We could find no significant correlation between the height of the second peak and the time from the initiation of therapy to hematological recovery. On the other hand, there was a significant positive correlation between the height of the second peak and the interval from the last day of chemotherapy to the peak (r = 0.62, p = 0.001), and there was a significant negative correlation between the peak height and the time from the peak until hematological recovery (defined as a neutrophil count of over 500/microliters (r = -0.63, p = 0.001) and a leukocyte count of over 1,000/microliters (r = 0.55, p = 0.008)). However, we found only a weak correlation between the peak height and monocyte recovery. These data suggest that increased M-CSF levels lead to the stimulation of granulocyte progenitors, and that we can predict the time of neutrophil recovery by monitoring the serum M-CSF level and finding its peak.

Adolescent↗

PubMed1992

Gene rearrangement and overexpression of PRAD1 in lymphoid malignancy with t(11;14)(q13;q32) translocation.

The proto-oncogene PRAD1 (parathyroid adenoma 1) on chromosome 11q13 was found to be overexpressed in all five B-cell lines with t(11;14)(q13;q32) translocation tested. One B-cell lymphoma and four myeloma cell lines with this translocation demonstrated more than 10-fold overexpression as determined by Northern blot analysis, when compared with normal lymphoid tissues such as thymus, spleen and lymph node. Hematopoietic cell lines without the translocation were also examined, but none of these demonstrated the overexpression, confirming that overexpression of the PRAD1 gene is associated with t(11;14) translocation. A truncated form of mRNA was seen in one of five cell lines with the translocation, SP-49. Hybridization with different regions of the PRAD1 cDNA revealed that the truncated form of mRNA retained the coding region but had lost the 3' untranslated region. Southern blot analysis demonstrated a gene rearrangement in this SP-49 cell line. To study the genetic alteration responsible for the truncated form of mRNA in this cell line, the rearranged allele as well as the germline allele were cloned. The restriction map revealed that the rearranged portion was at the 3' end of the PRAD1 gene, eliminating the mRNA-destabilizing signal AUUUA. Human-rodent hybrid cell analysis demonstrated that the region introduced 3' of PRAD1 was derived from chromosome 11, suggesting that the PRAD1 gene region is deleted at the 3' end. Over-expression of the PRAD1 gene in association with t(11;14)(q13;q32) translocation suggested that in these cases the regulation of PRAD1 was altered by the juxtaposed gene, most likely the immunoglobulin heavy-chain gene from chromosome 14.

Base Sequence↗

PubMed1991

'Ischemic tolerance' phenomenon detected in various brain regions.

We investigated the effects of mild and non-lethal ischemic insult on neuronal death following subsequent lethal ischemic stress in various brain regions, using a gerbil model of bilateral cerebral ischemia. Single 10-min ischemia consistently caused neuronal damage in the hippocampal CA1, CA2, CA3 and CA4, layer III/IV of the cerebral cortex, dorsolateral part of the caudoputamen and ventrolateral part of the thalamus. On the other hand, in double ischemia groups, 2-min ischemic insult 2 days before 10-min ischemia exhibited significant protection in the CA1 and CA3 of the hippocampus, the cerebral cortex, the caudoputamen and the thalamus. Five-min ischemic insult 2 days before 10-min ischemia also showed protective effect in the same areas as those of 2-min ischemia except for the CA1 region of the hippocampus, while 1-min ischemic insult exhibited no protective effect in any brain regions. In the immunoblot analysis, both 2- and 5-min ischemia caused increased synthesis of heat shock protein 72 (HSP 72) in the hippocampus, but 1-min ischemia did not. The present study demonstrated that the 'ischemic tolerance' phenomenon was widely found in the brain and also suggested that ischemic treatment severe enough to cause HSP 72 synthesis might be needed for induction of 'ischemic tolerance'.

Animals↗

PubMed1991

Elevated tissue concentrations of sialyl Lex-i in cancerous tissues compared with those in noncancerous tissues of various organs.

Sialyl Lex-i (SLX) concentrations in the extracts of noncancerous and cancerous tissues of various human organs were determined by radioimmunoassay for detailed evaluation of SLX. Cancerous tissues had significantly elevated SLX concentrations compared with noncancerous tissues of various organs. Tissue SLX concentration of the cancerous part was significantly higher than that of the adjacent noncancerous part in the same tissue. There was no significant correlation between tissue SLX concentration and serum SLX level. Positive localization of SLX was clearly observed in such cancerous tissues by immunohistochemical study, although not in any noncancerous tissues. Each of the antigens: SLX, CA 19-9, carcinoembryonic antigen, and CA 125 showed a different distribution pattern in tissue concentration or localization in various organs. These results indicate that SLX may be a valuable cancer-associated antigen produced by malignant tissues, suggesting its clinical application as a tumor marker.

Aged↗

PubMed1991

Temporal profile of serum albumin extravasation following cerebral ischemia in a newly established reproducible gerbil model for vasogenic brain edema: a combined immunohistochemical and dye tracer analysis.

We investigated the temporal profile of the extravasation of serum albumin in a reproducible gerbil model of unilateral cerebral ischemia, using immunohistochemical and dye-tracer techniques to evaluate albumin accumulation and the occurrence of active extravasation, respectively. After 30 min of cerebral ischemia and subsequent reperfusion, immunostaining for albumin became visible in the lateral part of the thalamus during the first 3 h, and then expanded to other brain regions up to 24 h. At both 24 h and 3 days after reperfusion, massive extravasation of albumin was noted in the whole ischemic hemisphere, and this had decreased again by 7 days after reperfusion. The extent and the degree of albumin immunopositivity were almost the same in all animals examined at each period after reperfusion. The extravasation of Evans blue, which was allowed to circulate for 30 min before death, was limited to the lateral part of the thalamus during the first 6 h of reperfusion. In the circumscribed area of massive albumin extravasation, many neurons were immunopositive for albumin; most of these neurons appeared to be intact and also showed immunostaining for microtubule-associated protein 2. The current investigation clearly demonstrated that (1) albumin extravasation was produced with reliable reproducibility in this model, (2) the lateral part of the thalamus was the region most vulnerable to ischemic blood-brain barrier damage, and (3) many apparently intact neurons in the ischemic region were positive for albumin.

Animals↗

PubMed1991

Analysis of methylation in the c-MYC gene in five human myeloma cell lines.

Genomic alterations of the human c-MYC gene were analysed in five human myeloma cell lines established in Kawasaki Medical School and compared with those of normal lymphocytes, Raji cells from Burkitt's lymphoma, and an Epstein-Barr virus positive lymphoblastoid cell line (LCL). Although no structural chromosome aberrations at 8q24, the c-MYC locus, were distinct, the mRNA level of c-MYC in these myeloma cell lines was 30-50-fold that in normal peripheral blood lymphocytes. Regarding the methylation of c-MYC, DNAs of the myeloma cell lines were digested with MspI plus EcoRI or HpaII plus EcoRI, and hybridized with three genomic 32P-labelled probes; the first, second and third exons of the human c-MYC gene, respectively. The extent of methylation in cytosine at a single CCGG site in the third exon substantially decreased in these myeloma cell lines as compared with that in normal tonsillar B, LCL and Raji cells. No significant differences in hypomethylation between these myeloma, normal B, LCL and Raji cells was detected in the first and second exon of c-MYC. These results suggest that the hypomethylation in the third exon of c-MYC might be related to the enhanced expression of c-MYC in these human myeloma cell lines.

Aged↗