Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 379 records · Page 21Linked to original sources

PubMed1997

()-form distribution seen in microvascular cast specimens of the filiform and fungiform papillae on the anterior central dorsal surface of the cat tongue.)

Three-dimensional structures of the microvascular network of the filiform papillae (FiP) and fungiform papillae (FuP) on the cat tongue were observed by the corrosion cast method under a scanning electron microscope (SEM). FiP can be classified into five types, types I-V and FuP into four types, types I-IV according to the shape and size of the main process (MP) and the number of the accessory processes (AP) which are found on the anterior central dorsal surface. FuP (I-IV) were found to be distributed sporadically among FiP (I-V). Each of the types I-V of FiP were arranged the form of a in an oblique line running from the anterior central zone to the posterior peripheral zone in an orderly and geometrical fashion. Each of the types I-IV of FuP were scattered throughout in line of FiPs arranged in the form of a , the point of which is directed at right angles towards the apex. FiP play an important role in the drinking of milk and water, holding, masticating and swallowing the food and, after mixing the food with saliva, in the transporting of the food mass towards the pharynx. The MP of FuP was considered to be a modified form of the MP of FiP of the cat tongue and to function as part of a sense organ for taste.

Animals↗

PubMed1997

Angioarchitectural comparison of the fungiform papillae of the cat and rabbit using scanning electron microscopic specimens.

The functional and morphological characteristics of the fungiform papillae (FuP) on the anterior dorsal surface of the cat and rabbit tongues were studied and compared using a scanning electron microscope (SEM), because the comparison of the functional and morphological relationship of FuP in microvascular cast specimens (MVCS) between these tongues is as yet not clear. In both species, FuP were found to be distributed sporadically among the numerous filiform papillae (FiP). In the cat, in particular, FuP were classified into four types (FuP I-IV) according to the shape and size of a main process (MP) and the number of accessory processes (AP). Each FuP, (FuP I-III lay along oblique lines of FiPs) contained a MP and many APs lying at the anterior basal margin of the MP, whereas FuP IV contained only the small fishnet-ball-shaped MP. In the rabbit, however, only the similar size and shape of the capillary loops, resembling the carnation flower, were scattered among FiPs on the anterior dorsal surface of the fore-tongue. These results suggest that in comparing the functional sense mechanism in both species, the FuP of the rabbit tend to be more simple than those of the cat in respect to taste sense.

Animals↗

PubMed1997

Purification and characterization of arylalkylamine N-acetyltransferase from cockroach testicular organs.

Arylalkylamine N-acetyltransferase (NAT; EC2.3.1.87) catalyzes N-acetylation of various arylalkylamines using acetyl-CoA as a donor substrate. A type of NAT was purified 2700-fold from 451 pairs of cockroach testicular organs consisting of testis and its accessory gland. The NAT activity was recovered as a single peak on any column chromatography examined, suggesting that the testicular organ contained only one form of NAT. Five steps of successive column chromatographies gave a single protein band on SDS-polyacrylamide gel electrophoresis with estimated molecular mass of 28 kDa. The molecular mass of the native enzyme was also determined to be approximately 30 kDa by molecular sieve chromatography, indicating that the enzyme is a monomer protein. The enzyme acted on various arylalkylamines such as tryptamine, serotonin, dopamine, octopamine, norepinephrine, tyramine and methoxytryptamine, with K(m) values ranging from 20 to 50 microM. The optimum pH for these substrates was around 6.0. Internal amino acid sequences derived from two proteolytic fragments of the enzyme were determined as Leu-Leu-Gly-Glu-Asn-Gly-Asp-Glu and Phe-Phe-Phe-Leu-Glu-Glu-Pro-Leu-Asn-Ile-Ser-Leu-Gln, both of which exhibited significant homology to the C-terminal sequence of known vertebrate NATs; however, homology was less than 45%. These results suggest that a unique NAT is present in the cockroach testicular organ at high levels, and likely plays a role in the regulation of testicular function.

Amino Acid Sequence↗

PubMed1997

Adriamycin (ADM) induced apoptosis in transitional cell cancer (TCC) cell lines accompanied by p21 WAF1/CIP1 induction.

Genotoxic stimuli, including anticancer drugs, induce apoptosis in cancer cells through increase of p53, p21WAF1/CIP1, at least in part. Bcl-2 and Bax modify this pathway or directly regulated by p53. Here we studied Adriamycin (ADM)-induced apoptosis in four human bladder cancer cell lines in respect of p53, p21WAF1/CIP1 and Bcl-2 family proteins. After ADM, treatment bladder cancer cells underwent dose-dependent cell death with typical morphologic features of apoptosis. Among four cell lines RT4 with wt p53, low ratio of Bcl-2 to Bax and induction of p21WAF1/CIP1 after ADM treatment, was the most sensitive to induction of apoptosis. Thus, p53, p21WAF1/CIP1, Bcl-2 and Bax status might determine susceptibility of bladder cancer cells to ADM induced apoptosis.

Journal Article↗

PubMed1997

An age-related change in susceptibility of rat brain to encephalomyocarditis virus infection.

Rats were inoculated intraperitoneally (i.p.) or intracerebrally (i.c.) with 1 x 10(4) plaque forming units (PFU)/animal of the D variant of encephalomyocarditis virus (EMC-D) at 2, 4, 7, 14, 28 or 56 days of age for virological and histopathological examination. In the i.p.-inoculation study, neither viral replication nor lesions were detected in the animals inoculated at 28 and 56 days of age. In the animals inoculated when younger than 14 days of age, lesions were restricted to the brain although viral replication was detected in the brain, heart and pancreas. The brain lesions were characterized by acute meningoencephalitis with neuronal necrosis in the cerebral cortex, hippocampus and thalamus, and viral RNA was detected in degenerated and/or intact neurons. In the i.c.-inoculation study, similar age-related changes in susceptibility of rat brain to EMC-D infection were observed, but a minor difference was that viral replication and lesions were still detected in the hippocampus of some animals inoculated at 28 days of age. These results suggest that an age-related decrease in the susceptibility of rat brain to EMC virus infection may reflect an age-related change in the susceptibility of neurons themselves as well as in maturation of the immune system.

Aging↗

PubMed1997

Thromboxane A2 mediates cisplatin-induced apoptosis of renal tubule cells.

The purpose of this study was to elucidate the role of thromboxane A2 (TXA2) in cisplatin-induced apoptosis of mouse renal cells derived from the terminal proximal tubule (S3). RT-PCR analysis revealed that S3 cells express TXA2 receptor mRNA. A TXA2 receptor antagonist, KW-3635, dose-dependently inhibited cisplatin-induced apoptosis of S3 cells. Treatment of S3 cells with a TXA2 agonist, STA2, induced a significant decrease in their viability and resulted in the characteristic ladder pattern resulting from intranucleosomal DNA cleavage. Treatment with KW-3635 resulted in attenuation of the increase in c-fos mRNA expression level in cisplatin-treated S3 cells. In conclusion, TXA2 appears to mediate cisplatin-induced apoptosis of S3 cells by inducing an increase in the level of c-fos mRNA expression.

Animals↗

PubMed1997

Identification of autophosphorylation sites in c-Yes purified from rat liver plasma membranes.

c-Yes was purified 322-fold from a rat liver plasma membrane fraction to a single 60-kDa band on SDS-PAGE. The purified protein contained essentially no phosphotyrosine residues and was autophosphorylated with Mg2+. ATP exclusively at tyrosine residues with a concomitant increase in the protein-tyrosine kinase activity. The autophosphorylated c-Yes was extensively digested by trypsin and the resultant two major phosphopeptides, peptides I and II, were purified by HPLC on a reversed-phase C-18 column. The amino acid sequence of peptide I was determined to be LIEDNEYTAR, which is identical with the sequence from Leu-418 through Arg-427 of mouse c-Yes, indicating that one of the autophosphorylation sites corresponds to Tyr-424 of the mouse c-Yes. After partial determination of the N-terminal sequence of 10 amino acid residues of peptide II, the 230 bp sequence of rat cDNA that encodes the N-terminal 76 amino acid residues of c-Yes covering peptide II, was determined. From the predicted amino acid sequence, the sequence of peptide II was assumed to be from Tyr-16 through Lys-46, YTPENPTEPVNTSAGHYGVEHATAATTSSTK. The purified c-Yes phosphorylated the tyrosine residue of synthetic peptides covering Tyr-32 and its surrounding sequence but did not phosphorylate peptides covering Tyr-16 and its surrounding sequence, suggesting that the other autophosphorylation site is Tyr-32.

Amino Acid Sequence↗

PubMed1997

Tissue and subcellular distributions, and characterization of rat brain protein phosphatase 2A containing a 72-kDa delta/B" subunit.

A 74-kDa delta/B" subunit was isolated by heparin-Sepharose column chromatography from human erythrocyte protein phosphatase 2A (PP2A) consisting of a 34-kDa catalytic subunit (alpha/C) and 63- and 74-kDa regulatory subunits (beta/A and delta/B") in a ratio of 1:1:1. The purified delta/B" was used as an immunogen in mice, to prepare specific antisera against delta/B". Immunoblot analyses with the antisera detected an immunoreactive 72-kDa protein in the cytosol from various rat tissues including erythrocytes, brain, lung, testis, adrenal gland, heart, spleen, kidney, and liver. The 72-kDa protein was highly abundant in brain and was distributed evenly in cerebral cortex, cerebellum, and brain stem. The 72-kDa protein was also detected in mitochondria and microsome fractions. An immunoreactive 68-kDa protein was detected mainly in nuclear and microsome fractions. The 72-kDa protein from rat brain cytosol copurified with phosphorylated H2B histone phosphatase activity during successive chromatographies on DEAE-Toyopearl, AH-Sepharose, Sephadex G-150, H1 histone-Toyopearl, TSK DEAE-5PW, protamine-Toyopearl, and TSK G3000SW columns. The purified enzyme migrated as a single protein band on nondenaturing PAGE and as three protein bands of 34, 63, and 72 kDa in a ratio of 1:1:1 on SDS-PAGE. The molecular weight of the enzyme was estimated to be 170,000 from the s20,W value of 7.2 +/- 0.3 S and the Stokes radius of 5.5 +/- 0.1 nm. The rat brain enzyme was classified as PP2A, based on the following properties; (1) an IC50 for okadaic acid of 10(-9) M; (2) its preferential dephosphorylation of the a subunit of phosphorylase kinase; (3) its insensitivity to protein inhibitor 2; and (4) its heterotrimeric subunit structure. The Km value and the molecular activity of the enzyme for phosphorylated H2B histone were 72.3 +/- 0.3 microM and 192 +/- 2 mol Pi released/min/mol enzyme, respectively, and were comparable to those of human erythrocyte PP2A (alpha1 beta1 delta1/ CAB"). The 72-kDa subunit in the purified rat brain PP2A was phosphorylated in vitro by cAMP-dependent protein kinase.

Animals↗

PubMed1997

Temporal and regional profiles of cytoskeletal protein accumulation in the rat brain following traumatic brain injury.

To characterize the cytoskeletal aberration due to traumatic injury, temporal and regional profiles of changes in immunoreactivity of microtubule-associated protein 2 (MAP2), neurofilament heavy subunit protein (NFH) and heat shock protein 72 (HSP72) were investigated after different magnitudes of traumatic brain injury by fluid percussion. The experimental rat brain was perfusion-fixed at 1, 6 and 24 hours after traumatic brain injury. Conventional histological staining has demonstrated that the mildest traumatic brain injury (1.0 atm) induced no neuronal loss at the impact site and that neuron loss was apparent when traumatic brain injury was increased to 4.3 atm. The mildest traumatic brain injury, however, caused a significant increase in HSP72 immunoreactivity in the superficial cortical layers at the impact site as early as 1 hour after the injury. In the case of severe traumatic brain injury (4.3 atm), neuron loss was apparent in the area at the impact site, but the increase in HSP72 immunoreactivity was moderate, and it was observed only after 6 hours in the deep cortical layers under the necrotic area. The increased immunostaining of MAP2 was demonstrated in damaged axons and neuronal perikarya in the wider area surrounding the impact site at 6 and 24 hours after the injury. Six and 24 hours after the injury, perikaryal accumulation of neurofilament was observed, and the accumulated neurofilament was mostly phosphorylated. These results indicate that the severe traumatic brain injury of 4.3 atm triggers the abnormal accumulation of cytoskeletal proteins in neuronal perikarya, most probably due to an impairment of axonal transport. It is implied that the increased expression of HSP72 may be involved in the protective process of neurons after traumatic brain injury.

Animals↗

PubMed1997

Dantrolene sodium reverses the increase in cAMP response element and TPA responsive element DNA-binding activity in the rabbit brain following haloperidol administration and heat stress.

Using electrophoretic mobility-shift assay (EMSA), we examined DNA-binding activity of cAMP response element (CRE), onto its responsive element CRE, as well as TPA responsive element (TRE) in the medial hypothalamus and striatum of the experimental rabbits administered with haloperidol under heat stress exposure and studied the effects of dantrolene sodium to the transcriptional factor. In EMSA with nuclear extracts from the rabbit brain, the DNA-binding activities of CRE and TRE in medial hypothalamus and striatum increased following haloperidol and heat stress. These increases were maintained by coadministration with atropine. The treatment with dantrolene sodium markedly reversed such increases. The alterations of activities of these transcriptional factors may reflect the therapeutic effect of dantrolene sodium.

Animals↗

PubMed1997

Absence of RET proto-oncogene mutations in a father and son with pheochromocytoma and pancreatic islet cell tumor.

BACKGROUND: We describe a father and son with a combination of pheochromocytoma and pancreatic islet cell tumor. Although its familial occurrence is rare, this syndrome could be called overlapping-type multiple endocrine neoplasia (MEN), since it fulfills the criteria for both type 1 and type 2 MEN. Recently, germ line mutations of the RET proto-oncogene (RET) were found to be related to tumorigenesis and disease phenotypes in type 2 MEN. METHODS: Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, we looked for germ line mutations of RET in 8 members of this family, including the 2 patients. RESULTS: Analysis of RET exons 10, 11 and 16, which contain the hot-spot codons for MEN type 2, revealed no mutations in any individual examined. CONCLUSION: These findings suggest that these 3 exons in RET are not related to tumorigenesis in overlapping-type MEN.

Adenoma, Islet Cell↗

PubMed1997

Heart rate variability in patients with familial amyloid polyneuropathy.

The purpose of this study was to evaluate heart rate variability (HRV) in patients with familial amyloid polyneuropathy (FAP) using the time- and frequency-domain analysis. The study population consisted of 19 patients with FAP, and 19 age and sex matched normal volunteers. The 24-hour Holter recordings of all subjects in sinus rhythm and off medication were analyzed. Five time-domain indices of HRV were computed. The frequency component of HRV was calculated by fast Fourier transform analysis of the RR intervals. The power spectrum of the low frequency (LF) between 0.04-0.15 Hz and high frequency (HF) between 0.15-0.40 Hz and the LF/HF ratio was calculated. Global measures of HRV including the standard deviation of the mean of RR intervals (SDNN) and the standard deviation of 5-minute mean RR intervals (SDANN) were decreased in patients with FAP. Specific vagal influences on HRV including the proportion of RR intervals more than 50 milliseconds different (pNN50) and the HF power on spectral analysis were less in patients with FAP. LF power and LF/HF ratio were more decreased in patients with FAP at the advanced stage than at the early stage. In conclusion, HRV was significantly decreased in patients with FAP at the early stage, and sympathetic activity was more decreased in patients at the advanced stage. These findings suggest that the decrease of the HRV is an indicator of this disease and the power spectral analysis of the HRV is beneficial in assessing the severity of the autonomic dysfunction.

Adult↗

PubMed1997

Photoperiodic time measurement and related physiological mechanisms in insects and mites.

For over 60 years, many species of insects and mites have been known to respond in an adaptive way to seasonal changes in daylength. Responses to photoperiod allow them to survive periods of unfavorable environmental conditions. Since the early 1950s, light-sensitive and temperature-compensated circadian clocks have also been known to regulate the timing of many events (behavioral, physiological, biochemical) in all eukaryotic organisms, including insects and mites. Over the past 30 years, considerable effort has been directed at elucidation of the nature of the clock mechanism that underlies photoperiodism. Mathematical models using a number of insect systems have been developed that attempt to causally relate the circadian clock to photoperiodic time measurement. Although some experimental evidence supports these circadian-based models, some insects and mites appear to utilize a non-periodic hourglass timer as the photoperiodic clock. Future work in this field would benefit by following the approach that has proven to be very successful in identifying genes and gene products that regulate circadian rhythmicity in Drosophila melanogaster.

Journal Article↗

PubMed1997

Induction of apoptosis in human eosinophilic leukemic cell line (EOL-1).

Exposure of human eosinophilic leukemic EOL-1 cells to H2O2, ascorbic acid derivatives, actinomycin D, low-molecular-weight polyphenols, UV irradiation, or hyperthermia resulted in nuclear fragmentation, but failed to induce internucleosomal DNA cleavage. The findings suggest that internucleosomal DNA fragmentation is not a universal biochemical hallmark of apoptosis. Removal of Ca2+ ions from the culture medium significantly reduced the cytotoxic activity of sodium ascorbate, but not that of H2O2. H2O2 significantly elevated the intracellular Ca2+ concentration, with or without Ca2+ in the culture medium. This suggests that sodium ascorbate and H2O2 initiate cell death by different mechanisms. Induction of apoptosis in in vitro systems might be useful in studying the pathogenesis of allergy or asthma.

Apoptosis↗

PubMed1997

Synthesis biological evaluation of alkyl, alkoxy, alkylthio, or amino-substituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones.

2,3-Dihydro-1,5-benzothiazepin-4(5H)-ones substituted with an alkyl, alkoxy, alkylthio, hydroxy, or amino group on the fused benzene ring of the 1,5-benzothiazepine skeleton were synthesized and their vasodilating, antihypertensive, and platelet aggregation-inhibitory activities were investigated. (-)-cis-3-Acetoxy-5-[2-(di-methylamino) ethyl]-2,3-dihydro-8-methyl-2-(4-methylphenyl)-1,5-benzothiazepin- 4(5H)-one ((-)-13e) was selected for further studies as a potent inhibitor of platelet aggregation.

Alkylation↗

PubMed1997

Apoptosis of murine hepatocytes induced by high doses of galactosamine.

Apoptosis induced by high doses of Galactosamine (GalN) was investigated in mice hepatocytes in vivo. In mice intraperitoneally (i.p.) treated with GalN 3 g/kg, the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells were first observed at 6 hr postadministration (PA). Both acidophilic bodies in hematoxylin and eosin (HE)-stained sections and TUNEL-positive cells were markedly found at 24 hr PA. At 48 hr PA, cellular degeneration and necrosis of hepatocytes were prominently observed, and TUNEL-positive cells were scarcely found. In the mice ip treated with GalN 1.5 g/kg, the lesion was milder than that in those treated with GalN 3 g/kg. Acidophilic bodies and TUNEL-positive cells were scarcely found at 24 hr PA, whereas they were markedly seen at 48 hr PA. In addition, a ladder-like DNA fragmentation pattern by agarose gel electrophoresis was observed most remarkably at 24 hr PA with GalN 3 g/kg and at 48 hr PA with GalN 1.5 g/kg, and less distinctly at 48 hr PA with GalN 3 g/kg. On the other hand, sGOT and sGPT activities increased prominently at 48 hr PA with GalN 3 g/kg. These results suggest that the cell death induced by high dose of GalN may be caused by apoptosis, and subsequently by necrosis in vivo.

Alanine Transaminase↗

PubMed1997

Response of respiratory epithelium of BN and F344 rats to formaldehyde inhalation.

BN rats are well-known for their high capacity for IgE production and hyperresponsiveness to exposure to allergens or other chemicals. We examined the histological changes in the nasal cavity, trachea and lungs of BN and F344 rats after the inhalation of aerosol formaldehyde (HCHO), which exerts direct toxic effects on the respiratory system. The incidence of clinical signs such as sneezing and abnormal respiration in HCHO-treated F344 rats was higher than that in HCHO-treated BN rats. The mean body weight of HCHO-treated F344 rats apparently decreased in comparison with control F344 rats, but that of HCHO-treated BN rats was not significantly different from that of control BN rats. Changes such as squamous metaplasia, stratification, degeneration and desquamation were observed by light microscopy in nasal, tracheal and bronchial mucosa in the lungs of the HCHO-treated F344 rats. In the HCHO-treated BN rats, similar but milder lesions were restricted to the nasal mucosa. Scanning electron microscopic observation supported these light microscopic observations. These results suggest that BN rats have lower sensitivity to HCHO inhalation than F344 rats.

Administration, Inhalation↗

PubMed1997

Detection of viral RNA by electron microscopic in situ hybridization (ISH-EM) in the germinal epithelium of mice infected with encephalomyocarditis (EMC) virus.

Electron microscopic in situ hybridization (ISH-EM) was first applied to the detection of viral RNA in the germinal epithelium of mice inoculated i.p. with 10(5) plaque-forming units/mouse of the D variant of encephalomyocarditis virus (EMC-D). Signals of viral RNA were first detected in a small number of Sertoli cells showing mild degeneration at 2 days post inoculation, and 2 days later, they were also detected in germinal cells and spermatogonia when Sertoli cells showed prominent degeneration. The results clearly demonstrated that the first site of viral attack in the germinal epithelium was Sertoli cell in the case of EMC-D-induced mouse orchitis.

Animals↗