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Biomedical subjects

M Tokuda

Publications and source records attributed to M Tokuda.

At least 127 records · Page 7Linked to original sources

Involvement of annexin I and annexin II in hepatocyte proliferation: can annexins I and II be markers for proliferative hepatocytes?

Annexin is the name of a new family of Ca(2+)-dependent membrane-binding proteins. Eleven types of its related proteins have been reported to date. Among those, annexin I and annexin II have been reported to possess many biological functions in vitro. Its actual role in vivo, however, is yet unknown. The involvement of annexin I and annexin II in the proliferation processes of hepatocytes was examined in the following aspects: (a) hepatocyte proliferation after carbon tetrachloride-induced liver damage, (b) hepatocyte regeneration after partial hepatectomy and (c) postnatal development of hepatocytes. These results showed collectively that annexin I and annexin II were increased in proliferative (or regenerative) hepatocytes, suggesting that both proteins play a certain role in the proliferation event. Furthermore, annexin I- and annexin II-positive hepatocytes always show a wider distribution than that of proliferating cell nuclear antigen or cytokeratin 7-positive hepatocytes, indicating that annexin I and annexin II may be useful markers for detecting not only actively proliferating hepatocytes but also hepatocytes in preproliferative and postproliferative stages.

Animals↗

Effect of ceruletide on epileptogenesis in amygdaloid kindled rats.

The inhibitory effects of ceruletide (CLT), a cholecystokinin-8 (CCK)-like peptide, were investigated in the epileptogenesis in the amygdaloid kindled rats. Lower doses of CLT (20-80 micrograms/kg) inhibited the progression of kindling process. After acquiring C5 stage, a higher dose (160 micrograms/kg) was required to suppress the seizure susceptibility. These results, in light of several previous studies showing no serious side effects, suggest that CLT might be useful as an anti-epileptogenic agent for clinical usage.

Amygdala↗

[Acute eosinophilic pneumonia: a report of two cases].

Two cases of acute eosinophilic pneumonia (AEP) are described and the radiographic findings discussed. Two patients presented acute fever and cough, which led to acute respiratory insufficiency in 3 days. There was no past history of asthma, hypersensitivity or allergy. They became well within 5 to 12 days, with corticosteroid in one and spontaneously in another. Bronchoalveolar lavage showed more than 80% eosinophils. Plain chest roentgenogram showed air space consolidation with peripheral predominance in case 1 and ground-glass shadow with reticular pattern in case 2. On CT, dense and faint air-space opacities were noted in both entire lung fields in case 1 and faint opacities with thickened interlobular septa in case 2. Bilateral pleural effusion and mild mediastinal lymphadenopathy were noted in both. The increased lung densities showed non-segmental distribution. However, these findings are non-specific and such opacities are seen in other diffuse lung diseases such as hypersensitive pneumonitis, BOOP and pulmonary edema. Pleural effusion (44% of reported cases including ours) and mediastinal lymphadenopathy were frequently seen, and pleural effusion with or without mediastinal lymphadenopathy could represent specific findings for this disease. The authors stress that in young patients with acute respiratory insufficiency with pleural effusion and/or mediastinal lymphadenopathy on the plain chest radiograph or on CT, the possibility of AEP should be considered in the differential diagnosis.

Acute Disease↗

Ceruletide suppresses rotational behavior in lesioned rats via CCKA receptors.

The effects and pharmacological mechanisms underlying the inhibiting effect of ceruletide, a cholecystokinin (CCK)-related peptide, on apomorphine-induced turning behavior in 6-hydroxydopamine lesioned rats were investigated. For this purpose, selective CCKA and CCKB receptor antagonists were used. Ceruletide (50-400 micrograms/kg, s.c.) dose dependently suppressed apomorphine-induced rotational behavior. The antiapomorphine effect of ceruletide was reversed by the selective CCKA receptor antagonist, devazepide, but not by the selective CCKB receptor antagonist, L-365,260. This suggests that the suppression ceruletide exerts on hyperactive nigrostriatal dopamine neurons is mediated by CCKA receptors.

Animals↗

Effect of embryonic hippocampal transplantation in amygdaloid kindled rat.

Embryonic neural tissue was transplanted into previously kindled rats. A thirteen- to fourteen-day embryonic hippocampal cell suspension was grafted in the stratum oriens near the CA2 area of the hippocampus. Almost 80% of the animals had a good recovery and became seizure-free. Injection of neocortical cells or saline did not show any positive effect on the kindling susceptibility. Although 20 day embryonic cell transplantation was also effective, the effect did not last as long as the 13- to 14-day embryonic transplantation. These observations open the possibility that the neural grafts may be used for therapy of medically intractable epilepsies.

Amygdala↗

Exogenous basic fibroblast growth factor and nerve growth factor enhance sprouting of acetylcholinesterase positive fibers in denervated rat hippocampus.

Basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) were administered into the rat brain following unilateral fimbria-fornix transection. Both bFGF and NGF stimulated the sprouting of acetylcholinesterase (AChE) positive fibers in the hippocampus on the lesioned side. Furthermore, a small number of AChE-positive fibers were regenerated even when only the vehicle was administered. Rats treated with NGF as well as control group had only thin fibers, whereas those treated with bFGF had not only thin fibers but also thick fibers. These results indicate that intrinsic NGF is released and acts on damaged neurons directly, while bFGF acts them on directly and/or indirectly after brain injury.

Acetylcholinesterase↗

[Alterations in morphological and phenotypical features of leukemic cells relapse 7 years after onset in a case of acute non-lymphocytic leukemia].

A case of acute non-lymphocytic leukemia who relapsed 7 years after the first remission is reported. The leukemic cells at onset had mature monocytic features with positive reactions for anti-CD14 antibody and alpha-NBE staining. By contrast, leukemic cells at relapse showed distinct morphological features from those at onset and lost their monocytic characters. No karyotypic abnormalities were found, but we could not exclude the possibility of secondary leukemia induced by the initial anti-leukemic chemotherapy.

Aged↗

[The administered activity of radionuclides in nuclear medicine--rational reduction of medical radiation exposure].

A survey of 104 hospitals was conducted to determine the administered activity of radionuclides. Eighty-five hospitals responded, and reported a total of 119,614 examinations in one year. The examinations included: bone scintigraphy, 26.4%; Thallium-201 (201Tl) myocardial scintigraphy, 15.5%; Gallium-67 (67Ga) scintigraphy, 13.3%; N-isopropyl-p-[123I]iodoamphetamine (IMP) brain perfusion scintigraphy, 7.0%. The administered activity was corrected by body weight only for children at more than 80% of the responding hospitals. The number of hospitals that reported over-administration of radionuclide varied according to the type of scintigraphy performed: bone, 76%; inflammatory (67Ga), 93%; myocardial (201Tl), 89.2%; brain (IMP), 8.5%. The administered activity of IMP was closer to the upper limits specified in the Recommendations on Standardization of Radionuclide Imaging by the Japan Radioisotope Association (1987), because IMP is very expensive and is supplied as single vials. The highest average effective dose was for myocardial scintigraphy, the second-highest for inflammatory scintigraphy, and the third-highest for bone scintigraphy. In 201Tl and 67Ga scintigraphy, the entire contents of the vial may be administered two days before the expiration date, because the ratio of (true patient administered activity) to (declared patient administered activity) is similar to the ratio of (radioactivity on the day of supply) to (radioactivity on the day of expiration). The factors that influence administered activity are throughput, price of the radionuclide, and whether the radionuclide is sold as a single vial. In order to decrease the effective dose, it is necessary to establish a close cooperation between medical personnel, the makers of radiopharmaceuticals, and manufacturers of gammacameras.

Humans↗

The evidence for post-meiotic expression of a testis-specific isoform of a regulatory subunit of calcineurin using a monoclonal antibody.

The expression of a regulatory subunit of calcineurin (CaN beta) during rat spermatogenesis was examined in rat testes using a monoclonal antibody Va1. Results showed that a testis-specific isoform of CaN beta was expressed only 3 weeks after birth, when meiosis begins, and increased in amount depending on the maturation of spermatogenesis. The matured sperm, which consists of only post-meiotic cells, is most likely to have only the testis-specific isoform of CaN beta. The brain type isoform of CaN beta was not detected in rat sperm. Immunoblot analysis of testes from different rodent species by a monoclonal antibody Va1 showed that all rodent species examined had their own homologues corresponding to a testis-specific isoform of CaN beta in rats, although they showed distinctively different molecular weights on SDS-PAGE compared to the testis-specific isoform in rats. Each homologue was shown to be specifically expressed in post-meiotic phase of spermatogenesis, as was seen in rats.

Aging↗

Identification of a src family protein specifically expressed in rat astrocytes by immunohistochemistry and double immunofluorescent study.

Identification of a src-related tyrosine kinase and its regional and cellular distributions were studied in rat brain. The study was performed using a specific antibody raised against a synthetic peptide corresponding to the conserved autophosphorylation site of src-family tyrosine kinases. The antibody (alpha-src antibody) recognized a 43 kDa polypeptide in plasma membrane enriched fraction. The immunohistochemical data revealed that the polypeptide is localized in astrocytes of corpus callosum and fimbria hippocampus. The presence of this src-related protein in astrocytes suggests that it may have some control in their proliferation and differentiation.

Animals↗

In vivo microdialysis of amino acid neurotransmitters in the hippocampus in amygdaloid kindled rat.

Extracellular concentrations of gamma-aminobutyric acid (GABA), glutamate (Glu) and aspartate (Asp) were determined by microdialysis in rat hippocampus during various amygdaloid kindled stages. The values of GABA and Glu were increased 3-4 times in C2-C3 stages in comparison with the values in control animals. After reaching the C5 stages, these values were increased 3-7 times. However, the concentration of Asp decreased depending on the kindling stage, reaching the lowest value of 33% in comparison with the normal value. The observed changes may be related to kindling induced seizures.

Amygdala↗

Identification of testis specific calcineurin beta subunit isoform by a monoclonal antibody and detection of a specific six amino acid sequence.

Two isoforms of calcineurin beta subunit(beta 1 and beta 2) were identified in rat testis by a monoclonal antibody Va1. Both beta 1 and beta 2 were recovered in calmodulin binding protein fraction and showed calcium shift on SDS-polyacrylamide gel electrophoresis which is the specific character for EF-hand calcium binding protein. beta 2 showed same apparent molecular weight on SDS-PAGE as that of brain calcineurin beta and was found in wide variety of tissues. beta 1 was shown to have six amino acid polypepeptide sequence and it showed higher molecular weight than brain beta and was specific for testis.

Amino Acid Sequence↗

Plasma urea and ammonia in epileptic patients and their relatives.

The plasma levels of urea and ammonia were examined in patients with primary generalized epilepsy, patients with partial epilepsy and in the first-degree relatives of these subjects. The results show a significant decrease in plasma urea in both groups of patients and their first-degree relatives as compared to the non-epileptic controls. The plasma ammonia concentrations were significantly higher in both groups of patients and in the relatives of generalized epilepsy patients as compared to the controls. The observed changes in plasma urea and ammonia were found not to be due to the effect of anticonvulsant drugs. The data suggest that a metabolic defect in urea synthesis may constitute one of the genetic components in the multifactorial etiologies of primary generalized and partial epilepsies.

Adolescent↗

Lipopolysaccharides of Bacteroides intermedius (Prevotella intermedia) and Bacteroides (Porphyromonas) gingivalis induce interleukin-8 gene expression in human gingival fibroblast cultures.

Lipopolysaccharides (LPS) prepared from Bacteroides intermedius (Prevotella intermedia) and Bacteroides (Porphyromonas) gingivalis by hot phenol-water extraction induced interleukin-8 (IL-8) mRNA in normal human gingival fibroblast cultures, as demonstrated by Northern (RNA) blot analysis. IL-8 mRNA levels began to increase after a 2-h exposure, reached a maximum after 12 h, and then dropped to the unstimulated level at 48 h. IL-8 mRNA levels were also enhanced in a dose-dependent manner. By contrast, LPS specimens from various Salmonella species with S and R chemotypes and bacterial [corrected] and synthetic lipid A preparations did not increase IL-8 mRNA levels in fibroblasts. Although recombinant human IL-1 alpha induced IL-8 mRNA expression in fibroblast cultures, an antiserum to recombinant human IL-1 alpha did not decrease the IL-8 mRNA accumulation induced by B. intermedius LPS. Fibroblasts primed with natural human gamma interferon (IFN-gamma) expressed higher IL-8 mRNA levels upon stimulation with B. intermedius LPS, but not with Salmonella LPS, compared with nontreated cells. Natural human IFN-beta exhibited a similar priming effect on the fibroblasts, and antiserum to IFN-beta added to the cultures together with B. intermedius LPS decreased the IL-8 mRNA levels. Therefore, endogenous IFN-beta enhanced IL-8 mRNA production in response to B. intermedius LPS in fibroblasts.

Bacteroides↗