Biomedical subjects

Y Tohyama

Publications and source records attributed to Y Tohyama.

At least 37 records · Page 2Linked to original sources

PubMed1999

Gene structure and amino acid sequence of Latimeria chalumnae (coelacanth) myelin DM20: phylogenetic relation of the fish.

The structure of Latimeria chalumnae (coelacanth) proteolipid protein/DM20 gene excluding exon 1 was determined, and the amino acid sequence of Latimeria DM20 corresponding to exons 2-7 was deduced. The nucleotide sequence of exon 3 suggests that only DM20 isoform is expressed in Latimeria. The structure of proteolipid protein/DM20 gene is well preserved among human, dog, mouse, and Latimeria. Southern blot analysis indicates that Latimeria DM20 gene is a single-copy gene. When the amino acid sequences of DM20 were compared among various species, Latimeria was more similar to tetrapods than other fishes including lungfish, confirming the previous finding by immunoreactivity (Waehneldt and Malotka 1989 J. Neurochem. 52:1941-1943). However, when phylogenetic trees were constructed from the DM20 sequences, lungfish was clearly the closest to tetrapods. Latimeria was situated outside of lungfish by the maximum likelihood method. The apparent similarity of Latimeria DM20 to tetrapod proteolipid protein/DM20 is explained by the slow amino acid substitution rate of Latimeria DM20.

Amino Acid Sequence↗

PubMed1999

Acute and chronic D-fenfluramine treatments have different effects on serotonin synthesis rates in the rat brain: an autoradiographic study.

The effects of acute and chronic treatments with D-fenfluramine on the regional rates of serotonin (5-hydroxy-tryptamine; 5-HT) synthesis were investigated using the alpha-[14C]methyl-L-tryptophan (alpha-[14C]MTrp) autoradiographic method. In the first series of experiments, acute D-fenfluramine treatment (5 mg/kg; i.p.) given 20 min before the tracer injection significantly (p<0.05) decreased 5-HT synthesis in the dorsal raphe, and significantly (p<0.05) increased the rates in the cerebral cortices and caudate nucleus, when compared to the rates in the control rats (saline treated). In a second series of experiments, following a 7-day treatment with D-fenfluramine (5 mg/kg/day; i.p.), a significant (p<0.05) decrease of 5-HT synthesis, in the dorsal raphe was observed, and significant (p<0.05) increases were observed in the hypothalamus, the dorsal thalamus, the medial and lateral geniculate body and some brain stem regions (locus ceruleus, inferior and superior colliculus). No significant changes were observed in the cerebral cortices.

Animals↗

PubMed1999

[Prototype of a new pediatric emergency scale tape: PES tape].

Drug dosage and appropriate size of medical equipment for emergency pediatric patients are determined by age, body weight and/or height. In an emergency situation, however, such information about the patients is not always clear. Body height is easily measured when the patient lies down supine. Furthermore, child's height could be a better parameter than age to predict appropriate endotracheal tube (ETT) size and body weight. We propose a new pediatric emergency scale tape (PES Tape). PES Tape is graduated in centimeters to measure body height in supine position. Height-based body weight, drug dosage, energy dosage for defibrillation, appropriate size of ETT and lip-tip distance (LTD) are printed on the tape. We studied the reliability of this tape in pediatric anesthesia. Body weight estimated from the tape was accurate, and predicted size of ETT and LTD was appropriate. PES Tape is a reliable tool in pediatric emergency.

Body Weights and Measures↗

PubMed1998

Consecutive in vivo measurement of nitric oxide in transient forebrain ischemic rat under normothermia and hypothermia.

The effects of hypothermia on production of nitric oxide (NO) in ischemic brain were investigated by using in vivo microdialysis. Male Wistar rats were randomly divided into three groups; saline-treated normothermic group (37 degreesC, n=6), 30 mg/kg N-nitro-l-arginine methyl ester(l-NAME)-treated normothermic group (n=6), and saline-treated hypothermic group (30 degreesC, n=6). Transient forebrain ischemia was produced by bilateral common carotid artery occlusion combined with hypotension (MABP=50 mmHg). Saline-treated normothermic animals resulted in a reduction of LCBF to 9% of baseline. Saline-treated hypothermic rats revealed the similar changes of LCBF. In contrast, l-NAME administration reduced the basal CBF to 85% of saline-treated group and to 8% after ischemia. NO products were decreased during ischemia and transiently increased after reperfusion in saline-treated groups. However, the increase of NO products after reperfusion was less significant in the hypothermia. l-NAME-treated group showed a constant reduction of NO production during ischemia and after reperfusion.

Animals↗

PubMed1998

Outside-In signaling of soluble and solid-phase fibrinogen through integrin alphaIIbbeta3 is different and cooperative with each other in a megakaryoblastic leukemia cell line, CMK.

The function and the outside-in signaling pathways of alphaIIbbeta3 were examined in relation to cell adhesion using a megakaryoblastic leukemia cell line, CMK. After 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment, the cells adhered to the culture plate and underwent megakaryocytic differentiation with expression of alphaIIbbeta3. Binding of soluble fibrinogen to the cells via alphaIIbbeta3 was dependent on cell adhesion. Cell detaching reduced the affinity of this integrin for soluble fibrinogen, although its surface expression was almost unchanged. In contrast, detached cells became tightly adherent to the fibrinogen-coated plate (solid-phase fibrinogen). The same ligand, fibrinogen, present either in soluble or solid-phase form, triggered differential signaling pathways mediated by alphaIIbbeta3. By the stimulation with soluble fibrinogen, Syk was tyrosine-phosphorylated but FAK was dephosphorylated, whereas solid-phase fibrinogen promptly caused tyrosine phosphorylation of FAK followed by delayed phosphorylation of Syk. In addition, the binding of soluble fibrinogen to the cells adherent to fibrinogen-coated plate resulted in tyrosine phosphorylation of integrin beta3 and a complex formation of integrin beta3 with Syk. This implies the cooperation of both soluble and solid-phase fibrinogen-mediated signaling pathways.

Cell Adhesion↗

PubMed1998

Hypothermia attenuates the activation of protein kinase C in focal ischemic rat brain: dual autoradiographic study of [3H]phorbol 12,13-dibutyrate and iodo[14C]antipyrine.

Using phorbol 12,13-dibutyrate (PDBu) autoradiography, we investigated the effect of hypothermia or protein kinase C (PKC) activation in rat brain 2 h after focal ischemia. In normothermia, a significant increase of PDBu binding was observed in ischemic brain. Hypothermia suppressed the increase of PDBu binding in degree and extent. These observations suggest that intraischemic hypothermia attenuates the activation of PKC, and this may in part be participate in the protective effect of hypothermia.

Animals↗

PubMed1998

Hypothermia attenuates hyperglycolysis in the periphery of ischemic core in rat brain.

Hypothermia has proven to be neuroprotective against ischemic brain injury. However, the exact mechanism has not yet been fully understood. In this study, we investigated the effects of hypothermia on cerebral glucose metabolism and blood flow in focal ischemic rats. Rats were divided into normothermic (37+/-0.5 degrees C) and hypothermic (30+/-0.5 degrees C) groups. Focal cerebral ischemia was induced by middle cerebral and ipsilateral common carotid arteries occlusion. Two hours after ischemia, autoradiographic studies of 2-deoxyglucose and iodoantipyrine were performed to measure local cerebral glucose utilization (LCGU) and cerebral blood flow. LCGU in the ischemic core was excessively reduced in both groups. However, a marked increase in LCGU was observed in the boundary zone of the ischemic core in normothermic rats. On the other hand, hyperglycolysis in the boundary zone of the ischemic core was suppressed in hypothermia. This attenuation of hyperglycolysis might be closely related to survival of the ischemic penumbra in hypothermia.

Animals↗

PubMed1998

[Imaging studies of excretory urography and computed tomography scan for patients suffering from renal colic].

Renal colic mainly due to urolithiasis is one of the most common morbid conditions in urology and commonly seen in the urology emergency clinic. Imaging studies were performed to evaluate the upper urinary tract of 29 patients suffering from renal colic in the 2 years between November, 1994 and October, 1996. After intramuscular injection of the analgesic (pentazocine, 15 mg), all 29 patients were examined by excretory urography (IVP) at the time of the first visit. In some patients abdominal plain computed tomography (CT) scan was performed consecutively even when extravasation of the contrast medium was not seen. Spontaneous peripelvic extravasation was seen in 14 patients (11 males and 3 females) with urolithiasis; 7 of them were diagnosed by IVP, 5 by IVP plus CT scan and 2 with CT scan only. IVP imaging study followed by plain abdominal CT scan is useful even when the contrast medium is not extravasated on IVP in patients suffering from renal colic.

Adult↗

PubMed1997

Interleukin-3 activates Syk in a human myeloblastic leukemia cell line, AML193.

Protein-tyrosine kinases and phosphatases play an important role in cytokine-mediated cell growth. The proliferation of a human myeloid leukemia cell line, AML193, is dependent on interleukin-3 (IL-3) or granulocyte colony-stimulating factor. In the current study, we demonstrated that a non-receptor-type protein-tyrosine kinase, Syk, was immediately activated by the stimulation with IL-3 or granulocyte colony-stimulating factor in AML193 cells. We further investigated the relation of Syk with IL-3-mediated signaling and found that the IL-3 receptor beta subunit was immunoprecipitated with Syk. Since the IL-3 receptor beta subunit is known to mediate growth signaling, our results indicate that Syk may be involved in the proliferation of myeloid cells.

Blotting, Western↗

PubMed1997

Protein kinase C in focal ischemic rat brain: dual autoradiographic analysis of [14C]iodoantipyrine (IAP) and [3H]phorbol-12,13-dibutyrate (PDBu).

Protein kinase C (PKC) activity was measured in rat brain with 2 h of middle cerebral artery (MCA) and common carotid artery (CCA) occlusion, using dual autoradiography of [14C]iodoantipyrine (IAP) and [3H]phorbol-12,13-dibutyrate (PDBu). In the ischemic brain, it required more than 120 min of incubation to obtain a plateau in PDBu binding. In contrast, the binding of PDBu in non-ischemic brain reached a plateau with incubation for 60 min. This delay of PDBu binding in the ischemic brain suggests that the affinity of this ligand is reduced due to a change in structure of the cell membrane caused by ischemia. PDBu binding in the ischemic brain increased significantly compared to the non-ischemic brain. This finding provides further evidence that excessive activation of PKC in the ischemic brain may play an important role in ischemic neuronal damage.

Animals↗

PubMed1997

Dissociation of 99mTc-ECD and 99mTc-HMPAO distributions in herpes simplex encephalitis.

In herpes simplex encephalitis (HSE), the authors noted an evident dissociation between the 99mTc-ethyl cysteinate dimer (ECD) and 99mTc-d,l-hexamethyl-propylene-amine oxime (HMPAO) single photon emission computed tomographies (SPECTs). The patient was a 5-year-old boy with diffuse type of pontine glioma, which was treated with hyperfractionated radiotherapy. Two weeks after the completion of radiation therapy, a lesion suggesting that of HSE was noted in the right fronto-temporal region on magnetic resonance images. 99mTc-HMPAO SPECT showed an increased accumulation of the tracer in this lesion. On the 99mTc-ECD dynamic SPECT, an exaggerated accumulation of the tracer was noted within 80 s of administration, followed by a rapid drop in the accumulation, resulting in a low accumulation in 10 min. It was assumed that this dissociation was due to the different mechanisms to trap HMPAO and ECD in the brain tissue.

Brain↗

PubMed1997

Prenatal determination of human platelet antigen type 4 by DNA amplification of amniotic fluid cells.

To predict a fetus at risk for neonatal alloimmune thrombocytopenia (NATP) caused by human platelet antigen (HPA)-4 incompatibility, we applied a sequence-specific polymerase chain reaction (PCR-SSP). We were able to determine the HPA-4 genotype of three infants at risk using amniotic fluid cells without the need for fetal blood sampling. The HPA-4 genotypes of amniotic fluid cells determined in this way were completely concordant with the genotype and phenotype of infants' venous blood samples obtained after delivery. Therefore, this technique is also convenient to a fetus at risk in the antenatal management of NATP induced by HPA-4 incompatibility.

Adult↗

PubMed1997

A comparative study of 2',3'-cyclic-nucleotide 3'-phosphodiesterase in vertebrates: cDNA cloning and amino acid sequences for chicken and bullfrog enzymes.

In mammalian brain, two 2',3'-cyclic-nucleotide 3'-phosphodiesterase (EC 3.1.4.37) isoforms, CNP1 and CNP2, are translated, respectively, from the two mRNAs, which have been transcribed and processed by alternative use of the two transcription start points and by differential splicing. In the present study, the cDNAs encoding chicken CNP2 and bullfrog CNP1, respectively, were isolated, and the amino acid sequences of chicken CNP2 and bullfrog CNP1 were deduced. Western blot analysis showed that chicken brain contains a major CNP2-type protein together with a minor unidentified isoform, and bullfrog brain contains only a CNP1-type protein. All available amino acid sequences of vertebrate 2',3'-cyclic-nucleotide 3'-phosphodiesterases were aligned and compared. Three conserved motif sequences were noted: (a) an ATP-binding site near the amino terminus, (b) an isoprenylation site at the carboxyl terminus, and (c) a probable catalytic site resembling the active site of beta-ketoacyl synthase (EC 2.3.1.41). The second and the third motifs are conserved also in goldfish RICH (regeneration-induced 2',3'-cyclic-nucleotide 3'-phosphodiesterase homologue), which has been shown recently to have 2',3'-cyclic-nucleotide 3'-phosphodiesterase activity. The third motif (probably catalytic site) was assigned for the first time in the present report.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗

PubMed1996

[A case of nonresectable advanced gastric cancer responding to combined chemotherapy with 5'-DFUR, CDDP, and MMC].

A 39-year-old man was referred for epigastric fullness and a mass in the umbilical region. A giant mass was palpated in the epigastric region, while a mass 1 cm in diameter with a hemorrhagic tendency was felt in the umbilical region. Fluoroscopy of the upper gastrointestinal tract and gastroscopy revealed a Borrmann 3 tumor in the upper part of the gastric corpus. The tumor was found by CT scanning to be growing clearly across the wall of the stomach, and the invasion to the transverse colon was suspected by the enema. The tumor was unresectable because of the extensive tumor invasion of the abdominal wall. Therefore, the patient received 2 courses of combined chemotherapy with 5'-DFUR, CDDP, and MMC. As a result, the tumor in the epigastric region was reduced dramatically, and it became unpalpable 6 months after treatment. At the same time, the tumor in the umbilical region disappeared. Both CT scanning and upper gastrointestinal radiography disclosed tumor reduction, and sufficient oral ingestion became possible. The administration of 5'-DFUR has since been continued as maintenance therapy. Aside from transient anorexia and slight leukopenia, the patient developed no symptoms during the treatment period. At present. 2 years and 9 months after starting chemotherapy, the patient is in good health.

Adult↗

PubMed1996

[Emphysematous cystitis: a case report].

Emphysematous cystitis is a rare condition in which gas-forming organisms produce gas in the bladder wall and lumen. We present a case of emphysematous cystitis with neurogenic bladder. The patient was a 78-year-old man who complained of dysuria and lower abdominal soft mass. Urine culture yielded Klebsiella pneumoniae and Enterococcus faecalis. A plain X-ray film of upright position showed a large air-fluid level. The gas was demonstrated in the bladder wall and lumen on CT scan. These findings were compatible with that of emphysematous cystitis. The symptoms were improved and the intraluminal gas had disappeared on radiography after treatment with antibiotics. We reviewed 20 cases of emphysematous cystitis reported in the Japanese literature and reported clinical characteristics of 21 patients including ours here.

Aged↗

PubMed1995

A novel factor-dependent human myelodysplastic cell line, MDS92, contains haemopoietic cells of several lineages.

A novel long-term cultured interleukin (IL)-3-dependent human myelodysplastic cell line, MDS92, was shown to contain several myeloid-lineage cells such as neutrophils, macrophages, eosinophils, and a small number of megakaryocyte-lineage cells. Therefore this cell line possesses at least bipotential characteristics of myeloid- and megakaryocyte-lineages. Granulocyte colony-stimulating factor clearly promoted the neutrophil alkaline phosphatase activity of MDS92 cells. To the contrary, the incidence and growth of CD41-positive cells were hardly affected by the addition of IL-6, IL-11, c-mpl ligand (thrombopoietin, TPO) or erythropoietin. TPO slightly supported the growth of CD34-positive cell fraction, but not CD41-positive cell fraction of MDS92 cells in combination with IL-3 or Steel factor. This cell line will be a useful tool for the study of MDS stem cells, but the mechanism of commitment of differentiation in MDS stem cells remains unknown.

Alkaline Phosphatase↗

PubMed1995

Neonatal alloimmune thrombocytopenia involving HPA-5b (Br(a)): a rare Japanese case.

Neonatal alloimmune thrombocytopenia (NAIT) is caused by platelet antigen incompatibility between the mother and fetus. The frequency of NAIT varies among ethnic groups. In Caucasians, HPA-5b (Br(a)) is the antigen that is second most frequently implicated. In Japan, NAIT due to anti-HPA-5b antibody is quite rare. The present case is the second case of Br(a)-NAIT in Japanese and the first case serologically confirmed by monoclonal antibody-specific immobilization of platelet antigens.

Antigens, Human Platelet↗

PubMed1994

Translocation of p72syk to the cytoskeleton in thrombin-stimulated platelets.

Thrombin stimulation induces a dramatic increase in the activity of p72syk in platelets. We have found that activated p72syk, which is phosphorylated on tyrosine residue(s), translocates from the Triton X-100-soluble fraction to the Triton X-100-insoluble, cytoskeleton-rich fraction after thrombin stimulation. In addition, the redistribution of p72syk from the 100,000 x g Triton X-soluble fraction and the membrane skeleton was found to correlate with an increased level of p72syk in the cytoskeleton. Furthermore, the early phase of p72syk translocation (within 60 s) was significantly inhibited with cytochalasin D, whereas the late phase of p72syk translocation (after 90 s) was completely inhibited with RGDS tetrapeptide treatment. These results suggest that translocation of the activated p72syk to the cytoskeleton correlates with different phases of the platelet activation process through actin polymerization and glycoprotein IIb/IIIa-fibrinogen-mediated aggregation of platelets and, hence, may have a regulatory role in tyrosine phosphorylation of platelets.

Animals↗