Search PubMed⌕ Search

Biomedical subjects

M Tajima

Publications and source records attributed to M Tajima.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Chemoradiotherapy with low-dose cisplatin and 5-FU for advanced esophageal cancer].

We evaluated the efficacy of chemoradiotherapy (CRT) for advanced esophageal cancer, from the view point of response. The relationship between chemo-radiosensitivity and dihydropyridine dehydrogenase (DPD), thymidylate synthase (TS), and p53 was investigated immunohistochemically. Thirteen patients with inoperable advanced esophageal cancer were involved in this study. CDDP of 10 mg/m2/day and 5-FU of 335 mg/m2/day were infused intravenously (day 1-5, day 15-19). Radiation was delivered concomitantly at a total dose of 30 Gy. Expressions of p53, DPD and TS were detected using immunohistology in the biopsy samples taken before CRT from 8 patients. Partial response was observed in 8 cases, no change in 4 cases, and progressive disease in one case. The overall response rate was 62%. The reduction rate was higher in tumors positive for p53 expression than in negative ones. The same was true for DPD and TS. The Treatment effect was more precisely predicted by combination of p53, DPD and TS. CRT with low-dose CDDP + 5-FU chemotherapy was effective and combination with p53, DPD, and TS might be a predictive marker for CRT in patients with advanced esophageal cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Functional characterization of structural alterations in the sequence of the vasodilatory peptide maxadilan yields a pituitary adenylate cyclase-activating peptide type 1 receptor-specific antagonist.

Maxadilan is a vasodilatory peptide derived from sand flies that is an agonist at the pituitary adenylate cyclase-activating peptide (PACAP) type 1 receptor. Surprisingly, maxadilan does not share significant sequence homology with PACAP. To examine the relationship between structure and activity of maxadilan, several amino acid substitutions and deletions were made in the peptide. These peptides were examined in vitro for binding to crude membranes derived from rabbit brain, a tissue that expresses PACAP type 1 receptors; and induction of cAMP was determined in PC12 cells, a line that expresses these receptors. The peptides were examined in vivo for their ability to induce erythema in rabbit skin. Substitution of the individual cysteines at positions 1 and 5 or deletion of this ring structure had little effect on activity. Substitution of either cysteine at position 14 or 51 eliminated activity. Deletion of the 19 amino acids between positions 24 and 42 resulted in a peptide with binding, but no functional activity. The capacity of this deletion mutant to interact with COS cells transfected with the PACAP type 1 receptor revealed that this peptide was a specific antagonist to the PACAP type 1 receptor.

Amino Acid Sequence↗
PubMed1999

Nitric oxide down-regulates Epstein-Barr virus reactivation in epithelial cell lines.

Nitric oxide (NO), a mediator of biological functions, has an antimicrobial activity against a variety of pathogens including viruses. In this study, we found that a constitutive, low level of inducible NO synthase (iNOS) mRNA was expressed in the EBV-infected gastric tissue-derived GT38 and GT39 cell lines, by analysis with the reverse transcription-polymerase chain reaction (RT-PCR) and Southern blotting. Treatment of these cells with a specific NOS inhibitor, NG-monomethyl-L-arginine (L-NMMA), induced the immediate-early, EBV transactivator gene BZLF1 protein ZEBRA, suggesting a significant increase in EBV reactivation by L-NMMA. Northern blotting demonstrated that BZLF1 and BRLF1 transcripts were also induced by 12-O-tetradecanoylphorbol-13 acetate (TPA). Meanwhile, constitutive expression of iNOS mRNA was inhibited by TPA. L-NMMA also enhanced TPA-induced expression of the BZLF1 gene. On the other hand, a NO donor, S-nitroso-N-acetylpenicillamine (SNAP), which releases NO in an aqueous solution, inhibited the TPA-induced BZLF1 gene expression in a dose-dependent manner at both mRNA and protein levels. These results demonstrated that NO is a regulatory factor in maintaining virus latency via inhibiting EBV reactivation in the infected epithelial cells.

Animals↗
PubMed1999

Suppression of FRP-1/CD98-mediated multinucleated giant cell and osteoclast formation by an anti-FRP-1/CD98 mAb, HBJ 127, that inhibits c-src expression.

When anti-CD98 mAb 6-1-13, 4-5-1, or 38-2-2 was added to the culture fluids of monocytes, extensive cell aggregation and polykaryocyte formation were induced. These multinucleated giant cells were tartrate-resistant acid phosphatase (TRAP) positive. On the other hand, when monocytes were incubated with another anti-CD98 mAb, HBJ 127, polykaryocyte formation was not detected, although extensive cell aggregation was induced. When HBJ 127 and 6-1-13 were simultaneously added to the culture fluids, anti-CD98 mAb-induced cell fusion was inhibited almost completely. HBJ 127 suppressed formation of 6-1-13-induced cell fusion in a dose-dependent manner. If, however, HBJ 127 was added after incubation of monocytes with mAb 6-1-13 for 6 h, an appreciable degree of TRAP-positive polykaryocyte formation was found. The bindings of 6-1-13 and HBJ 127 were not mutually competed. When monocytes were incubated with 6-1-13 or HBJ 127, 6-1-13 induced c-src mRNA, while HBJ 127 did not. Furthermore, when monocytes were incubated with both 6-1-13 and HBJ 127, c-src mRNA could not be detected, showing that HBJ 127 suppresses c-src expression. Therefore, CD98-mediated osteoclast formation can be regulated by modification of CD98 system.

Antibodies, Monoclonal↗
PubMed1999

Reduced glutathione accelerates the oxidative damage produced by sodium n-propylthiosulfate, one of the causative agents of onion-induced hemolytic anemia in dogs.

The oxidative effects of sodium n-propylthiosulfate, one of the causative agents of onion-induced hemolytic anemia in dogs, were investigated in vitro using three types of canine erythrocytes, which are differentiated by the concentration of reduced glutathione and the composition of intracellular cations. After incubation with sodium n-propylthiosulfate, the methemoglobin concentration and Heinz body count in all three types of erythrocytes increased and a decrease in the erythrocyte reduced glutathione concentration was then observed. The erythrocytes containing high concentrations of potassium and reduced glutathione (approximately five times the normal values) were more susceptible to oxidative damage by sodium n-propylthiosulfate than were the normal canine erythrocytes. The susceptibility of the erythrocytes containing high potassium and normal reduced glutathione concentrations was intermediate between those of erythrocytes containing high concentrations of potassium and reduced glutathione and normal canine erythrocytes. In addition, the depletion of erythrocyte reduced glutathione by 1-chloro-2, 4-dinitrobenzene resulted in a marked decrease in the oxidative injury induced by sodium n-propylthiosulfate in erythrocytes containing high concentrations of potassium and reduced glutathione. The generation of superoxide in erythrocytes containing high concentrations of potassium and reduced glutathione was 4.1 times higher than that in normal canine erythrocytes when the cells were incubated with sodium n-propylthiosulfate. These observations indicate that erythrocyte reduced glutathione, which is known as an antioxidant, accelerates the oxidative damage produced by sodium n-propylthiosulfate.

Anemia, Hemolytic↗
PubMed1999

Diesel exhaust particulate induces airway hyperresponsiveness in a murine model: essential role of GM-CSF.

BACKGROUND: Inhaled pollutants were recently shown to be responsible for an increased incidence of airway allergic diseases, including asthma. A common feature of all forms of asthma is airway hyperresponsiveness. OBJECTIVE: Our purpose was to elucidate the effects of diesel exhaust particulate (DEP), one of the most prevalent inhaled pollutants, on airway responsiveness. METHODS: A/J and C57Bl/6 mice were used; the former are genetically predisposed to be hyperresponsive to acetylcholine, whereas the latter are not. DEP was administered intranasally for 2 weeks, after which pulmonary function was analyzed by whole-body plethysmography. RESULTS: Intranasal administration of DEP increased airway responsiveness to acetylcholine in both A/J and C57Bl/6 mice and induced displacement of ciliated epithelial cells by mucus-secreting Clara cells. The effect was mediated by M(3) muscarinic receptors. Acetylcholine-evoked bronchial constriction was reversed by administration of terbutaline, a beta(2)-adrenergic antagonist, which is also characteristic of human asthma. Intranasal administration of antibody raised against GM-CSF abolished DEP-evoked increases in airway responsiveness and Clara cell hyperplasia. The antibody raised against IL-4 also inhibited DEP-evoked increases in airway responsiveness. However, it was to a lesser extent compared with antibody against GM-CSF. In addition, DEP stimulated GM-CSF messenger RNA expression in the lung. CONCLUSION: DEP induces airway hyperresponsiveness by stimulating GM-CSF synthesis.

Acetylcholine↗
PubMed1999

Gender differences in molecular remodeling in pressure overload hypertrophy.

OBJECTIVES: The objective of this study was to examine gender differences in left ventricular (LV) function and expression of cardiac genes in response to LV pressure overload due to ascending aortic stenosis in rats. BACKGROUND: Clinical studies have documented gender differences in the pattern of adaptive LV hypertrophy. Whether these differences result from intrinsic differences in molecular adaptation to pressure overload between men and women, or are related to other factors is not known. METHODS: Male (n = 8) and female (n = 8) Wistar rats underwent ascending aortic stenosis and were studied 6 weeks after banding with gender-matched control rats (male n = 7; female n = 7). The LV contractile reserve was examined in isolated hearts from each group. We compared LV messenger ribonucleic acid (mRNA) levels of atrial natriuretic factor (ANF), beta-myosin heavy chain, sarcoplasmic reticulum Ca2+-adenosine triphosphatase (ATPase) and Na+-Ca2+ exchanger. Reverse transcriptase polymerase chain reaction was used to identify estrogen receptor transcript in cardiac myocytes and LV tissue. RESULTS: The magnitude of LV hypertrophy (LVH) and systolic wall stress were similar in male and female animals with LVH. Male LVH hearts demonstrated a depressed contractile reserve; in contrast, contractile reserve was preserved in female LVH hearts. The expression of beta-myosin heavy chain and ANF mRNA was greater in male versus female LVH hearts. Sarcoplasmic reticulum Ca2+-ATPase mRNA levels were depressed in male LVH but not in female LVH compared with control rats, and Na+-Ca2+ exchanger mRNA levels were increased similarly in both male and female LVH hearts. Estrogen receptor transcript was detected in both adult male and female cardiac myocytes and LV tissue. CONCLUSIONS: There are significant gender differences in the LV adaptation to pressure overload despite a similar degree of LVH and systolic wall stress in male and female rats. There is the potential for estrogen signaling through the adult myocyte estrogen receptor in both male and female rats to contribute to gender differences in gene expression in pathologic hypertrophy.

Adaptation, Physiological↗
PubMed1999

Gene expression during osteoclast-like cell formation induced by antifusion regulatory protein-1/CD98/4F2 monoclonal antibodies (MAbs): c-src is selectively induced by anti-FRP-1 MAb.

Human blood monocytes can differentiate into osteoclast-like cells when they are cultured in the presence of anti-FRP-1. Messenger (mRNA) expression of markers related to osteoclasts was analyzed during differentiation of osteoclasts from monocytes. As markers related to osteoclasts, we selected cathepsin-K, carbonic anhydrase (CA) II, vacuolar H(+)-ATPase (v-ATPase), vitronectin receptor (VNR), tartrate-resistant acid phosphatase (TRAP), osteopontin (OPN), galectin-3, c-src, c-fos, and c-fms. The mRNAs other than c-src mRNA were expressed in freshly isolated monocytes or monocytes incubated with control antibody or anti-FRP-1 monoclonal antibody (MAb) for 14 days. Of these mRNAs, cathepsin-K, CA II, v-ATPase, VNR, TRAP, OPN, and c-fms mRNAs were expressed at higher levels in the osteoclast-like cells than those in monocytes cultured with control antibody. On the other hand, galectin-3 mRNA was expressed at lower levels in the osteoclast-like cells, and there was no significant difference in c-fos mRNA expression between the monocytes cultured with control antibody and anti-FRP-1 MAb. c-src mRNA could not be detected in monocytes freshly isolated or incubated with control antibody. Surprisingly, expression of c-src mRNA was induced in monocytes by anti-FRP-1 MAb and was detectable as early as 3 h after anti-FRP-1 MAb treatment, indicating that c-src is selectively induced by anti-FRP-1 MAb treatment. Furthermore, the osteoclast-like cells expressed calcitonin receptor. Receptor activator of NF-kappaB (RANK) mRNA was detectable in freshly isolated monocytes or monocytes cultured with control antibody or anti-FRP-1 MAbs. Maximal expression of RANK was observed in osteoclast-like cells. On the other hand, no receptor activator of NF-KB ligand (RANKL) mRNA was detectable in any of the samples, suggesting that anti-FRP-1 mAb can induce osteoclast-like cells from blood monocytes without RANKL.

Antibodies, Monoclonal↗
PubMed1999

Possible causes of diabetes mellitus in cattle infected with bovine viral diarrhoea virus.

In cattle, we encountered insulin-dependent diabetes mellitus (IDDM) associated with bovine viral diarrhoea virus (BVDV) infection. To estimate the correlation between IDDM and BVDV infection, the distribution of BVDV in the pancreas and islet-cell antibody (ICA) were investigated. The distribution of BVDV in the pancreas was examined by in situ hybridization using two oligonucleotide probes that recognized the gp25- and p14-coding regions of the BVDV gene. ICA was examined by indirect fluorescence antibody assay using the sera from affected cattle and pancreata from normal cattle. In the pancreata of all BVDV-infected cattle, including IDDM-complicated cattle, oligonucleotide probe hybridized portions were recognized. In short, BVDV genes were detected not only in IDDM-complicated cattle but also in uncomplicated cattle. Moreover, there was no hybridized portion in the islet cells. In BVDV-infected and IDDM-complicated cattle, ICA was frequently detected. On the other hand, ICA was not detected in BVDV-infected and IDDM uncomplicated cattle. These results suggest that IDDM associated with BVDV infection is not a direct effect of BVDV on islet cells. Therefore, as BVDV did not induce IDDM in any cases, it appears that BVDV does not induce IDDM directly, but rather may be an autoimmune disease induced by autoantibodies against islet cells.

Animals↗
PubMed1999

Isolation and characterization of monoclonal antibodies directed against murine FRP-1/CD98/4F2 heavy chain: murine FRP-1 is an alloantigen and amino acid change at 129 (P<-->R) is related to the alloantigenicity.

Nineteen mAb directed against murine fusion regulatory protein-1 (mFRP-1)/4F2/CD98 were isolated and their biological properties were analysed. Intriguingly, mFRP-1 was found to be an alloantigen, namely, FRP-1.1 (DBA/2 and CBA mice type) and FRP-1.2 (BALB/c, C57BL/6 and C3H/He mice type). The nucleotide sequences of FRP-1.1 and FRP-1.2 were determined, demonstrating that amino acid change at 129 (P<-->R) is related to the alloantigenicity. mFRP-1 is expressed on thymocytes, on spleen cells, on peripheral lymphocytes and on blood monocytes, suggesting that the physiological role in vivo of murine FRP-1 is different from that of human FRP-1. The biological activities of antimFRP-1 mAbs showed by the present study are: (i) enhancement of Newcastle disease virus-induced cell fusion; (ii) suppression of HIVgp160-mediated cell fusion; and (iii) induction of aggregation and multinucleated giant cells of monocytes/macrophages.

Amino Acid Sequence↗
PubMed1999

Relation between erythrocyte reduced glutathione and glutamate concentrations in Korean Jindo dogs with erythrocytes possessing hereditary high activity of Na-K-ATPase and a high concentration of potassium.

The concentrations of sodium, potassium, reduced glutathione (GSH) and free amino acids and Na-K-ATPase activity in erythrocytes were examined in 35 purebred Jindo dogs in Korea. The incidence of Jindo dogs with a high potassium concentration and high activity of Na-K-ATPase in erythrocytes (HK phenotype) was 25.7%. The erythrocyte GSH concentration in HK Jindo dogs varied widely, from 2.45 to 12.38 mmol/l of RBCs, and was positively correlated with the erythrocyte glutamate concentration. These results indicate that HK Jindo dogs have normal to very high levels of erythrocyte GSH, which might result from the varying quantity of Na-dependent glutamate influx in the erythrocytes.

Animals↗
PubMed1999

Spontaneous lymphoma in a Japanese White rabbit.

Lymphoma was observed in a 4-month-old female Japanese White rabbit. Grossly, the markedly enlarged mesenteric lymph nodes, prominent Peyer's patches of jejunum, splenomegaly, and enlargement of tracheobronchial lymph nodes, adrenal glands and ovaries were observed. Histologically, neoplastic lymphoid cells proliferated diffusely showing frequent mitotic figures and a characteristic 'starry sky' appearance. Their basophilic cytoplasm contained a few lipid droplets. The mesenteric lymph nodes, Peyer's patches of jejunum, and tracheobronchial lymph nodes were largely replaced by the tumor tissues. The stomach, small intestines, especially the jejunum, liver, spleen, ovaries, and adrenal glands were heavily infiltrated with neoplastic cells. These results suggest that the present lymphoma may have originated from the gastrointestinal lymphoid tissue.

Animals↗
PubMed1999

Rumen bacteria are involved in the onset of onion-induced hemolytic anemia in sheep.

The mechanism of onion-induced hemolytic anemia in ruminants was investigated. The ether-extract obtained from the mixture of rumen fluid and onion juice incubated at 38.5 degrees C for 9 hr induced oxidative damage in sheep erythrocytes in vitro, indicating the production of certain oxidants in the mixture. The increase of the oxidative effect in the mixture was inhibited completely by the removal of rumen microorganisms and partly by treatment with antibiotics and by oxygen gas. The sheep fed onions (50 g/kg body weight/day) for 15 days developed more severe Heinz body hemolytic anemia than did the sheep fed the equivalent amount of onions with 5 g/day ampicillin sodium salt. The results indicated that certain rumen bacteria appear to be involved in the onset of onion-induced hemolytic anemia in sheep.

Anemia, Hemolytic↗
PubMed1999

Histopathological and immunohistochemical analysis of the endocrine and exocrine pancreas in twelve cattle with insulin-dependent diabetes mellitus (IDDM).

Histological and immunohistochemical studies were carried out on the pancreas of twelve cattle of insulin-dependent diabetes mellitus (IDDM). They showed clinical signs such as persistent hyperglycemia, glycosuria and decreased glucose tolerance, and some cases accompanied with or without ketonuria. Histopathologically, eight cattle were diagnosed as chronic IDDM, while others were acute IDDM. The most characteristic lesions of the pancreas in chronic IDDM showed a decrease in the size and number of pancreatic islets, interlobular and interacinar fibrosis, mild lymphocytic insulitis, and vacuolation of a few islets. Almost all cells in the atrophied islets had a small amount of ungranulated cytoplasm. Immunohistochemical examination revealed that the atrophied islet cells did not react to anti-insulin antibody, but occasionally reacted to anti-glucagon or somatostatin antibodies. A few solitary islets with mild lymphocytic infiltration, necrotic islets with occasional calcification, and atrophied islets with mild fibrosis were also observed. A few islets consisted of many islet cells with vacuolated cytoplasm including a small number of insulin-positive granules. Accumulation of glycogen granules was occasionally observed in these islets. Islet fibrosis was due to the proliferation of collagen fibers reactive to both anti-collagen type I and type III antibodies. In acute IDDM, the major islets consisted of the cells with vacuolated cytoplasm indicating the degranulation of islet cells. These islets contained many islet cells with shrunken cytoplasm and karyorrhectic nuclei. Lymphocytic infiltration was frequently observed in the islets which consisted of many islet cells having karyorrhectic nuclei and vacuolated and severely degranulated cytoplasm. Immunohistochemically, islet cells with vacuolated cytoplasm had a small amount of insulin-positive granules, suggesting severe degranulation of beta-cells. An increase in acinar islet-cells and proliferation of ductal epithelial cells showing insulin-immunoreactivity were observed. Bovine IgG-immunoreactive islet cells were frequently seen in the vacuolated islets. In summary, pathological observations suggested that beta-cells were being destroyed by an inflammatory process which selectively affected the pancreatic islets. Lymphocytic insulitis and anti-bovine immunoreactive islet cells were thought to be the most significant changes in determining the etiology and pathogenesis of bovine IDDM, and suggested their role in anti-islet autoimmunity in this form of diabetes.

Animals↗
PubMed1999

Pattern formation in polyrhythmic tapping at a self-paced tempo.

The present study examined the pattern formation in complex bimanual coordination at a self-paced tempo. 10 subjects performed two motor tasks in a self-paced situation, a single-rhythmic tapping with the preferred hand and a 3:2 polyrhythmic tapping with the right hand taking the faster beat. To clarify the process of polyrhythmic pattern formation, the transition routes of frequency ratios were analyzed. Analysis showed that a 3:2 pattern was formed by transition repeatedly shifting among 1:1, 2:1, and 3:1 patterns. Consequently, transitions were induced from a simple dissipative structure to a more complex dissipative structure. This process could be represented as a shift from lower- to higher-order ratios in the Farey tree. Furthermore, close relationships were indicated between personal tempo in the polyrhythmic tapping with the faster hand and in the single-rhythmic tapping.

Adult↗
PubMed1999

[Benign clear cell tumor of the lung diagnosed by transbronchial biopsy].

A 26-year-old woman had an abnormal shadow on chest X-ray films during a general medical examination. A chest roentgenogram showed a nodular shadow 8 mm in diameter in the middle field of the right lung. Transbronchial biopsy specimens revealed that the coin lesion was a benign clear cell tumor. Benign clear cell tumors of the lung are rare; only 21 cases, including the present case, have been reported in Japan. Although the diagnosis in most of the cases reported required an open thoracotomy, for our patient the diagnosis was based solely on the findings of a transbronchial biopsy.

Adult↗