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Biomedical subjects

Y Tamai

Publications and source records attributed to Y Tamai.

At least 109 records · Page 6Linked to original sources
PubMed1995

Suppression of azoxymethane-induced colonic aberrant crypt foci by dietary exposure to a novel synthesized retinoidal butenolide, 5-hydroxy-4-(2-phenyl-(E)ethenyl)-2(5H)-furanone, in rats.

The modifying effect of dietary exposure to a novel synthesized retinoidal butenolide, 5-hydroxy-4-(2-phenyl-(E)ethenyl)-2(5H)-furanone (KYN-5) on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) was investigated in male F344 rats. Animals were given weekly s.c. injections of AOM (15 mg/kg body wt.) for 3 weeks to induce ACF. These rats were fed diet containing 100 or 200 ppm KYN-54 for 5 weeks, starting 1 week before the first dosing of AOM. All rats were killed 2 weeks after the last AOM injection, to measure the number of ACF, ornithine decarboxylase (ODC) activity, mucosal polyamine level, and silver-stained nucleolar organizer regions protein (AgNORs) count per nucleus in the colon. In rats given AOM and KYN-54, the frequency of ACF/colon was significantly decreased compared with that in rats given AOM alone. ODC activity and polyamine levels, and the mean AgNORs number in the colon of rats given AOM and KYN-54 at both doses were also significantly lower than that of rats treated with AOM alone. These results provide further evidence that KYN-54 could be a chemopreventive agent against rat colon carcinogenesis.

4-Butyrolactone↗
PubMed1995

Mouse Elk oncogene maps to chromosome X and a novel Elk oncogene (Elk3) maps to chromosome 10.

The Elk protein is a member of the Ets family found in both vertebrates and invertebrates. Human ELK1 encoded by ELK1 binds alone or together with serum response factor to DNA and regulates gene expression in a variety of biological processes. Using a panel of interspecific backcross mice, we have mapped the Elk oncogene (Elk) and a novel type Elk oncogene (Elk3), closely related to ELK1. Elk maps to Chr X, and Elk3 maps to the proximal region of Chr 10.

Animals↗
PubMed1995

Characterization of Na+/H(+)-antiporter gene closely related to the salt-tolerance of yeast Zygosaccharomyces rouxii.

In order to clarify the relationship between salt-tolerance of Zygosaccharomyces rouxii and the function of Na+/H(+)-antiporter, a gene was isolated from Z. rouxii which exhibited homology to the Na+/H(+)-antiporter gene (sod2) from Schizosaccharomyces pombe. This newly isolated gene (Z-SOD2) encoded a product of 791 amino acids, which was larger than the product encoded by its Sz. pombe homologue. The predicted amino-acid sequence of Z-Sod2p was highly homologous to that of the Sz. pombe protein, but included an extra-hydrophilic stretch in the C-terminal region. The expression of Z-SOD2 was constitutive and independent of NaCl-shock. Z-SOD2-disruptants of Z. rouxii did not grow in media supplemented with 3 M-NaCl, but grew well in the presence of 50% sorbitol, indicating that the function of Z-SOD2 was closely related to the salt-tolerance of Z. rouxii. Several genes are also compared and discussed in relation to the salt-tolerance of Z. rouxii.

Amino Acid Sequence↗
PubMed1995

Monohexosylceramides of larval and adult forms of the tapeworm, Spirometra erinacei.

The occurrence of glycosphingolipids with unique carbohydrate structures in different species of cestode, Platyhelminth, which had been shown previously, prompted us to study the molecular species of the monohexosylceramides (cerebrosides) in the pseudophyllidean cestode, Spirometra erinacei. The purpose of the study was to obtain a basis for future investigations of the physiological role of glycolipids in parasitism. Cerebrosides were isolated from S. erinacei at two growth stages, i.e., from the larval form (plerocercoid) and from the adult tapeworms (intestinal form). The cerebrosides were separated into four subfractions by silica gel column chromatography, and their constituents were analyzed by gas-liquid chromatography, gas chromatography/mass spectrometry, and high-performance liquid chromatography/mass spectrometry. The hexoses of the cerebrosides consisted primarily of galactose in both growth stages, while only a small amount of glucose was detected. The ceramides were composed of sphinganine (d18:0) and phytosphingosine (t18:0) as sphingoid bases, and of nonhydroxy fatty acids ranging from C16 to C30 and hydroxy stearic acid (18h:0). The cerebrosides of adult tapeworms contained more 18h:0 than those of plerocercoids. The combination of hexoses and ceramides in the cerebroside molecules was slightly different in the two growth stages: the glucocerebrosides of plerocercoids contained only d18:0-nonhydroxy fatty acids in their ceramide moieties, whereas those of adult tapeworms contained varying ceramide moieties. Our data indicate that the molecular species of glycolipids present were essentially homeostatic throughout growth in spite of the entirely different environmental conditions, although there were slight differences in the hexose distribution in the two growth stages.

Animals↗
PubMed1995

Pregnancy outcome among long-term survivors with acute leukemia.

By means of a mail questionnaire, we evaluated the influence of treatment for acute leukemia on offspring of long-term survivors and determined whether the outcome of pregnancy in patients (or spouses) induced relapse of acute leukemia. In 322 replies from the 445 institutions where a questionnaire was sent, there were 1136 adult long-term survivors. We analyzed the 43 adults who had become pregnant or become a father after postremission therapy. The mean age at the leukemia onset was 26.4 and 21.6 years for males and females. Forty-six normal children (26 boys and 20 girls) were born of long-term survivors including 7 pairs of siblings and a pair of twin sisters. There were no malformed babies. There were five abortions. The average duration until delivery was 79 months after diagnosis, and 49 months after the final postremission therapy. Four of 38 parents of live offspring died (3 relapse, 1 other disease), and the other 34 parents of live offspring were in complete remission at the point of this survey. The adverse effect of treatment on the offspring of long-term survivors could not be clarified in this survey. Additional lifetime follow-up of long-term survivors with acute leukemia and their offspring may be necessary.

Acute Disease↗
PubMed1995

Chemoprevention of azoxymethane-induced intestinal carcinogenesis by a novel synthesized retinoidal butenolide, 5-hydroxy-4-(2-phenyl-(E)-ethenyl)-2(5H)-furanone, in rats.

The present study was designed to investigate the modifying effects of dietary 5-hydroxy-4-(2-phenyl-(E)-ethenyl)-2(5H)-furanone (KYN-54), a new synthetic retinoidal butenolide, during the post-initiation phase on azoxymethane (AOM)-induced rat intestinal carcinogenesis. The number of aberrant crypt foci (ACF) in rat colon, colonic ornithine decarboxylase (ODC) activity and bromodeoxy-uridine (BrdUrd) labeling index in rat colonic epithelium were also assessed. At 7 weeks of age, male F344 rats (except the KYN-54 alone and control groups) were given weekly s.c. injections of AOM at 15 mg/kg body wt for 3 weeks. Starting 1 week after the last injection of AOM, rats (except the control group) were fed a diet containing KYN-54 at concentrations of 100 or 200 p.p.m. throughout the experiment. All animals were necropsied at 32 weeks after the start of the experiment. Compared with the AOM alone group, KYN-54 at both doses reduced the incidence and multiplicity of tumors in entire intestine (small and large intestines). In the 200 p.p.m. KYN-54 fed group especially, tumor incidence and multiplicity in the entire intestine were lower compared with the AOM alone group (P < 0.005 and P < 0.05 respectively). Also, the number of ACF/cm2 colon in the groups of rats treated with AOM and KYN-54 at both doses were significantly lower than that of rats treated with AOM alone (P < 0.05). Colonic ODC activity and BrdUrd labeling index in the groups of rats treated with AOM and KYN-54 at both doses were slightly lower than those treated with AOM alone. KYN-54 at 200 p.p.m. significantly lowered BrdUrd labeling index induced by AOM (P < 0.005). These results suggest that KYN-54 might be a promising chemopreventive agent for intestinal neoplasia.

4-Butyrolactone↗
PubMed1995

Inhibition of 4-nitroquinoline-1-oxide-induced rat oral carcinogenesis by dietary exposure of a new retinoidal butenolide, KYN-54, during the initiation and post-initiation phases.

The modifying effect of dietary exposure of a newly synthesized retinoidal butenolide, 5-hydroxy-4-(2-phenyl-(E)-ethenyl)-2(5H)-furanone (KYN-54) during the initiation and post-initiation phases of oral carcinogenesis initiated with 4-nitroquinoline-1-oxide (4-NQO) was investigated in male F344 rats. At 6 weeks of age, rats were divided into experimental and control groups. At 7 weeks of age, all animals except those treated with KYN-54 alone and those in a control group were given 4-NQO (20 p.p.m.) in the drinking water for 8 weeks to induce oral neoplasms. Seven days after stopping 4-NQO exposure, groups of animals fed the diets containing 100 and 200 p.p.m. KYN-54 for 10 weeks starting 1 week before 4-NQO exposure were switched to the basal diet and kept on this diet until the end of the experiment. Starting 1 week after the cessation of 4-NQO administration, the groups given 4-NQO and the basal diet were switched to the diets containing 100 or 200 p.p.m. KYN-54 and maintained on these diets for 22 weeks. The other group consisted of rats given 200 p.p.m. KYN-54 alone or untreated rats. All animals were necropsied at the termination of the study (week 32). The incidences of tongue neoplasms and preneoplastic lesions, polyamine levels in the tongue tissue, and cell proliferation activity estimated by bromodeoxyuridine (BrdU)-labeling index and by morphometric analysis of silver-stained nucleolar organizer regions protein (AgNORs) were compared among the groups. Feeding of KYN-54 during either initiation or post-initiation phase caused a significant reduction in the frequency of tongue carcinoma (48-71% reduction, P < 0.05) and such chemopreventive efficacy was dose-related. The incidences of preneoplastic lesion in rats fed the diets mixed with KYN-54 at both doses were also decreased (P < 0.05). Dietary administration of KYN-54 also significantly decreased the labeling index of BrdUrd and the number of AgNORs per cell nucleus of the tongue squamous epithelium (P < 0.05). In addition, polyamine levels in the oral mucosa were lowered in rats given 4-NQO and test compound when compared to those given 4-NQO alone, but no significant difference was obtained. These results indicate that the novel synthesized retinoidal butenolide KYN-54 inhibits oral carcinogenesis initiated with 4-NQO and such inhibition may be related to suppression of cell proliferation.

4-Butyrolactone↗
PubMed1995

Distribution of the Kexin family proteases in pancreatic islets: PACE4C is specifically expressed in B cells of pancreatic islets.

The distribution of Kexin family proteases in adult rat pancreatic islets was investigated by immunohistochemical means using a series of specific antibodies specific for PC1, PC2, PC6, Furin, PACE4A and a recently identified member of the Kexin family, PACE4C. PACE4C expression was limited to B cells of the pancreatic islets. PC2 was found in A and in some D cells more than in B cells and PC1 was evident only in B cells. Furin and PC6 were weakly and evenly expressed in the entire islet. PACE4A was hardly found in the islets. These findings indicated that individual Kexin family proteases are uniquely distributed in the islets and suggested that these proteases share roles in these cells as follows: PC2 is involved in the peptide hormone precursor processing in A cells and in D cells, and PACE4C, PC1 and PC2 (mainly PACE4C and PC1) are responsible for the processing event(s) specific to B cells.

Animals↗
PubMed1995

Effects of inorganic phosphorus compounds on the hydrolysis of phosphatidylcholine liposomes by phospholipid-deacylating enzymes.

Structural requirements of inorganic phosphorus compounds as specific activators or inhibitors for phospholipase A2 and phospholipase B were investigated using orthophosphate, pyrophosphate and polyphosphate. It was observed that orthophosphate and pyrophosphate stimulated the activities of phospholipase A2 from bee venom, snake (Naja naja) venom and pig pancreas, and also phospholipase B from the yeast Torulaspora delbrueckii. However, polyphosphate was found to act as an inhibitor for phospholipase A2 in the above species and also for phospholipase B from T. delbrueckii. Orthophosphate and pyrophosphate induced gradual aggregation of liposome, but polyphosphate prolonged the lifetime of the liposome, suggesting that orthophosphate and pyrophosphate destabilize the bilayer structure of phosphatidylcholine and polyphosphate stabilizes it.

Acylation↗
PubMed1995

[Quantitative bleeding time].

Bleeding time, which reflects the interaction of the platelets with the damaged vessel wall and the subsequent formation of the primary hemostatic plug, has been widely used in the diagnosis of bleeding disorders, especially platelet abnormalities. We have developed a computerized method to measure the bleeding pattern and the amount of blood loss from the bleeding time incision (quantitative bleeding time). In 87 normal subjects (51 males and 36 females), the bleeding time was 389 +/- 137 sec and the amount of blood loss was 15.7 +/- 7.2 microliters (mean +/- S.D.). The bleeding pattern was classified into four types (I-IV). Type II showed the prolongation of the bleeding time, continuous constant bleeding, and considerably large amount of blood loss from the incision. This type which includes severe von Willebrand disease and serious thrombocytopenia is related to the severe bleeding tendency. Type III exhibited the prolongation of the bleeding time keeping a trace of blood loss from the incision. In type III patients, the bleeding tendency was generally mild despite the prolonged bleeding time as in patients with moderate thrombocytopenia or aspirin ingestion. Measurement of bleeding pattern and blood loss will provide a useful information to evaluate the defect of primary hemostasis.

Adolescent↗
PubMed1994

Cloning and sequencing of phospholipase B gene from the yeast Torulaspora delbrueckii.

The extracellular phospholipase B gene from baker's yeast Torulaspora delbrueckii was cloned and sequenced. Analysis of DNA sequence data revealed an open reading frame (ORF) encoding a 649-amino acid protein, that included amino acid sequences obtained from the purified enzyme. Comparison of these sequence data with the N-terminal amino acid sequence of the enzyme indicated that this secreted protein is synthesized as a large precursor with a 21-amino acid N-terminal extension to the mature enzyme of 628 amino acids. A homology search was carried out between phospholipase B from T. delbrueckii and Penicillium notatum. The deduced amino acid sequence of the cloned phospholipase B was homologous (about 50% identity) to phospholipase B from P. notatum, and contained six conserved regions. The transcriptional level of mRNA of the phospholipase B gene was higher in the cells from early exponential and stationary phases.

Amino Acid Sequence↗
PubMed1994

Evaluation of the functional connectivity in the nervous system using time dependent scatter diagrams.

We investigated spike trains of the feline nervous system, which are considered to be non-stationary point processes characterized by changes of the functional interneuronal connectivities. Ordinary long-term averaged correlation methods are useful as processing time series data as a quasi-stationary point process, but not as a non-stationary point process. We depicted the joint impulse configuration scatter diagram proposed by D. H. Perkel et al. for subsets of the neural spike-train to find changes of functional connectivities. The time-dependent scatter diagram was generated by arranging these scatter diagrams in chronological order. Time-dependent scatter diagrams were generated for spike trains derived from the anterior ectosylvius sulcus, the coronal sulcus, the lateral bank of the presylvius sulcus, the medial wall of the presylvius sulcus, and the medial wall of the cruciate sulcus. The patterns of time-dependent scatter diagrams for these cortices are considered to change in relation to eye movement. Changes of these patterns correspond to those of the functional connectivities related to the dynamics of eye movement in the neural system.

Animals↗
PubMed1994

The tissue distribution of mRNAs for the PACE4 isoforms, kexin-like processing protease: PACE4C and PACE4D mRNAs are major transcripts among PACE4 isoforms.

In the previous study [Biochem. Biophys. Res. Commun. (1994) 200, 943-950] we identified two novel cDNAs (PACE4C and PACE4D) encoding human Kexin-like protease, the PACE4 isoforms. In this study, we examined the expression of PACE4 isoform transcripts in various rat tissues. To detect very low levels and to distinguish among these isoforms, we used the reverse transcriptase-polymerase chain reaction (RT-PCR). PACE4C and PACE4D transcripts were detected in most tissues like PACE4A transcripts, however their tissue distribution profiles and the extent of expression differ. PACE4C and PACE4D transcripts are expressed at a much higher level than PACE4A transcript. These results indicate that PACE4C and PACE4D mRNAs are major transcripts of PACE4.

Animals↗
PubMed1994

A novel member, PC7, of the mammalian kexin-like protease family: homology to PACE4A, its brain-specific expression and identification of isoforms.

By polymerase chain reaction (PCR) with primers corresponding to the sequences of catalytic domain conserved among the mammalian kexin-like protease family, a cDNA fragment encoding a novel member of the family was obtained from rat pituitary. A cDNA for the novel protease was obtained from three overlapping clones isolated from a rat pituitary cDNA library using the PCR product as a screening probe. The protein, designated as PC7, encoded by this cDNA contained a putative activation site with the sequence RXKR, subtilisin-like catalytic domain and a homo B region which are typical of mammalian kexin-like proteases, and short cysteine-rich region at the carboxyl-terminal end. It exhibited surprising sequence similarity to PACE4A. The PC7 transcript was expressed at high levels in the brain. However it was undetectable in the liver, kidney, heart, and spleen. The presence of PC7 isoforms (PC7A and PC7B) was also shown.

Amino Acid Sequence↗
PubMed1994

Identification of novel cDNAs encoding human kexin-like protease, PACE4 isoforms.

PACE4 has been identified as a second human subtilisin-like protease by Keifer et al. [DNA and Cell Biology (1991) 10, 757-769]. In this study, we isolated two novel cDNAs coding for PACE4 isoforms (PACE4C and PACE4D) from a human placenta cDNA library. The deduced PACE4C protein sequence (652 amino acids) lacks the cysteine-rich region located at the carboxy terminus of PACE4. The DNA sequence of the 3'-untranslated region (1 kb) of PACE4C is not homologous to the PACE4 sequence. The protein (497 amino acids) encoded by PACE4D cDNA lacks a signal peptide, a propeptide and the cysteine-rich region. These isoform cDNAs were also isolated from rat pituitary cDNA library.

Amino Acid Sequence↗
PubMed1994

Prenatal ethanol exposure affects the activity and mRNA expression of neuronal membrane enzymes in rat offspring.

In order to elucidate molecular mechanisms underlying brain dysfunction in offspring exposed to ethanol in utero, subclinical doses of ethanol that do not have apparent structural effect on the offspring were administered intraperitoneally to pregnant rats at various gestational stages. We measured the activity of membrane marker enzymes and the level of mRNA of myelin proteins of the offspring brain. The activity of a myelin specific enzyme, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) decreased in ethanol-exposed offspring. This effect was not related to the period of gestation or the dose of ethanol. Perikaryonal enzymes, acetylcholinesterase and Na+, K(+)-ATPase, were significantly affected in groups exposed to ethanol at early fetal stage and in high doses. Expression of mRNAs of CNP and myelin basic proteins decreased significantly in the ethanol-treated group, with abnormal developmental profile suggesting a relationship with delayed myelination in offspring exposed to ethanol in utero. The present findings suggest that in spite of the low doses of ethanol that do not cause clinical symptoms in the offspring, prenatal exposure to ethanol affects the level of mRNA of membrane enzyme proteins in the offspring brain, consequently causing a corresponding reduction in enzyme activity, that may lead to neuronal dysfunction. In a separate study, blood ethanol levels were found to reach a maximum level within 30 min after injection and be undetectable after 5 to 10 h. No accumulation effects due to daily injection were observed.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1994

Molecular cloning, sequence analysis, and expression of the yeast alcohol acetyltransferase gene.

The ATF1 gene, which encodes alcohol acetyltransferase (AATase), was cloned from Saccharomyces cerevisiae and brewery lager yeast (Saccharomyces uvarum). The nucleotide sequence of the ATF1 gene isolated from S. cerevisiae was determined. The structural gene consists of a 1,575-bp open reading frame that encodes 525 amino acids with a calculated molecular weight of 61,059. Although the yeast AATase is considered a membrane-bound enzyme, the results of a hydrophobicity analysis suggested that this gene product does not have a membrane-spanning region that is significantly hydrophobic. A Southern analysis of the yeast genomes in which the ATF1 gene was used as a probe revealed that S. cerevisiae has one ATF1 gene, while brewery lager yeast has one ATF1 gene and another, homologous gene (Lg-ATF1). Transformants carrying multiple copies of the ATF1 gene or the Lg-ATF1 gene exhibited high AATase activity in static cultures and produced greater concentrations of acetate esters than the control.

Acetyltransferases↗