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Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 433 records · Page 24Linked to original sources
PubMed1996

The distributive pattern, form and function seen in microvascular cast specimens of filiform papillae on the anterodorsal surface of the adult rat tongue.

The purpose of the present study was to examine in detail the distributive pattern, form and function of small conical papillae (SCP) and of filiform papillae (FIP) in the anterodorsal part of the adult rat fore-tongue in a microvascular cast specimen (MVCS), with the scanning electron microscope (SEM), and to elucidate the close relationship between the morphological characteristics and the function of the tongue. From the results obtained in this study, SCP in the anterior part were subdivided into three types: SCP type I, II and III according to the shape, size, distributive pattern and form taken from the two peripheral sides as for as the median sulcus (MS) in the central portion. The results we obtained suggested that the primary role of SCP types I and II at the apex may be mainly that of touch and attachment to the food and water, while SCP types II and III in the anterior part function efficiently by taking the food and water from both peripheral sides to the MS or central portion, and finally transporting it into the oral cavity and supporting the mastication system.

Animals↗
PubMed1996

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

Since the precise reasons for the functional and morphological relationship of the filiform papillae (FP) in microvascular cast specimens (MVCS) between the cat and rabbit tongue are as yet not clear, the functional and morphological characteristics of FP on the anterior dorsal surface of these tongues were studied and compared by scanning electron microscopy (SEM). In both species, numerous FP are usually inclined toward the pharynx. In the cat, in particular, there were five types of FP in which types I-III contained a main process (MP) and many accessory processes (AP), and the concave network aspect of their spoon-like and complex MP faced toward the posterior part of the tongue. In the rabbit, numerous FP showed the same type but without AP. The concave network aspect of their arrow-head-like and loose tips faced in an anterior direction, which was the opposite direction to those in the cat FP. These results suggest that the directional difference in the concave network face of MP on FP in both species i.e., the cat and the rabbit, is due to the difference in feeding habits.

Animals↗
PubMed1996

Relation between distribution of viral RNA and development of histopathological changes in encephalomyocarditis virus-induced orchitis in mice.

The relation between the distribution of viral RNA and the development of histopathological changes was investigated in the early stage of encephalomyocarditis (EMC) virus-induced orchitis in mice. Signals of viral RNA were first detected by in situ hybridization in a few Sertoli cells in almost intact germinal epithelia at 2 days post-inoculation (d.p.i.). The number of Sertoli cells bearing signals of viral RNA increased at 3 d.p.i. when mild degenerative changes were exceptionally found in germinal epithelia. Signals of viral RNA came to be detected not only in Sertoli cells but also in a small number of germinal cells and spermatogonia at 4 d.p.i. when mild to moderate degenerative changes developed in germinal epithelia, resulting in desquamation of degenerated cells. At the same time, virus-like particles were observed by electron-microscopy in the degenerated and desquamated germinal cells. At and after 5 d.p.i., luminal obstruction with cellular debris and inflammatory cells was generally found. These results suggest that EMC virus carried to seminiferous tubules via the blood first attacks Sertoli cells and then damages germinal cells and spermatogonia.

Animals↗
PubMed1996

ATP-induced calcium mobilization in glomerular mesangial cells is mediated by P2U purinoceptor.

To identify the functional P2 purinoceptor subtype in glomerular mesangial cells (GMC), polymerase chain reaction coupled with reverse transcription (RT-PCR) were performed, and cytosolic free calcium concentration ([Ca2+]i) was determined. RT-PCR analysis revealed that the molecular identity of P2 purinoceptor localized to GMC was both P2U and P2Y. The rank order of potency in stimulating [Ca2+]i was ATP [symbol: see text] UTP > 2-methylthio-ATP > ADP [symbol: see text] adenosine [symbol: see text] AMP. In addition, cross-desensitization between ATP and UTP occurred. In conclusion, ATP induces increase in [Ca2+]i via P2U purinoceptor in GMC.

Adenosine Diphosphate↗
PubMed1996

Phagocytic cells in the taste buds of rat circumvallate papillae after denervation.

Phagocytic cells in the taste buds of rat circumvallate papillae after the sectioning of bilateral glossopharyngeal nerves were examined by electron microscopy and immunohistochemistry. Electron micrographs taken 1 day after denervation revealed that flat-shaped cells were present just beneath the taste buds and that their cellular processes extended toward the debris from the degenerating taste buds. At 2-6 days after denervation, long and thin processes of the flat cells surrounded the debris and appeared to have taken them up into the cytoplasm as small vesicles. Evidence for phagocytosis by the flat cells was seen up to 9 days after denervation and again at 24 and 40 days, in correlation to the degeneration and regeneration of the taste buds. Pre-embedding immunohistochemistry using anti-vimentin antibody showed that flat cells strongly reacted with vimentin. Light microscopic immunohistochemistry using anti-macrophage antibodies (ED1, ED2) showed that throughout the post-operative days macrophages were not present underneath or within the taste buds. Most of the ED2-immunoreactive resident macrophages were located in the deep layer of connective tissue, and a few were found in the nerve bundle. ED1-immunoreactive cells were seen in the duct cells of von Ebner's glands and a few were in the trench wall of circumvallate papillae; however, they were also immunoreactive for anti-OX62 antibody, which recognizes dendritic cells. The results indicate that the phagocytic cells of the taste buds are fibroblasts, not macrophages. Moreover, resident macrophages participate in phagocytosis of degenerated nerves together with Schwann cells.

Animals↗
PubMed1996

Depletion of Mac1-positive macrophages protects DBA/2 mice from encephalomyocarditis virus-induced myocarditis and diabetes.

DBA/2 mice treated with anti-Mac1 monoclonal antibody (MAb) failed to develop encephalomyocarditis virus (EMCV)-induced diabetes and myocarditis. Virus concentrations and the number of viral RNA-positive cells in the pancreas and heart were significantly reduced in mice treated with anti-Mac1 MAb. Mac1-positive macrophages seem to be involved in EMCV-induced disease and to affect the replication of EMCV in target organs.

Animals↗
PubMed1996

Mutational screening of APP gene in patients with early-onset Alzheimer disease utilizing mismatched PCR-RFLP.

To elucidate the frequency of mutations of the beta/A4 amyloid protein precursor (APP) gene in early-onset Alzheimer disease, we designed a mismatched PCR-RFLP that can identify all kinds of missense mutations at codon 717 in addition to the seven kinds of known mutations at exon 17. When we screened mutations at exon 17 utilizing this method and the double missense mutations at exon 16 of the APP gene by PCR-RFLP, no cases revealed mutations of the APP gene among 13 familial and 54 sporadic cases, except one family (OS-1) that had previously been reported and used as a positive control of APP717(Val-->Ile). Our results support the hypothesis that mutations in the APP gene are not major causes in early-onset Alzheimer disease.

Adult↗
PubMed1996

Attitudes of medical students towards persons with mental disorders: a comparative study between Japan and Thailand.

This study was conducted at three universities, two in Japan and one in Thailand, in order to elucidate the effects of medical education, especially with regard to contact experience on medical students' attitudes toward persons with mental disorders. Questionnaires, which included the Attitudes Towards Disabled Persons Scale (ATDP) and the Contact with Disabled Persons Scale (CDP), were distributed to 1st year students prior to the commencement of their medicine/psychiatry studies and distributed to 6th (or 5th) year students who had completed their psychiatric curriculum. The ATDP scores were lower for 6th year students at all universities, suggesting that post-education students had a more unfavorable attitude than pre-education students. Thai students indicated more unfavorable attitudes than did the Japanese students. Three factors were extracted from the ATDP scale and termed: negation of character, negation of ability and affirmation of normality. Four factors from the CDP scale were extracted and labeled intimate contact experience, ordinary contact experience, unpleasant contact experience and pleasant contact experience. Greater negative attitudes of post-education students than pre-education students were thought to attribute mainly to an increase in factor score of negation of ability and this result was correlated with an increase in factor score of ordinary contact experience in post-education students. Of the three ATDP factor scores, the higher score of Thai students for negation of character contributed to their overall unfavorable attitude scores. The cross-national similarities and differences of students' attitudes towards and contact experience with mentally disordered persons were discussed from the viewpoint of medical education.

Attitude↗
PubMed1996

KW-3902, a selective high affinity antagonist for adenosine A1 receptors.

1. We demonstrate that 8-(noradamantan-3-yl)-1,3-dipropylxanthine (KW-3902) is a very potent and selective adenosine A1 receptor antagonist, assessed by radioligand binding and cyclic AMP response in cells. 2. In rat forebrain adenosine A1 receptors labelled with [3H]-cyclohexyladenosine (CHA), KW-3902 had a Ki value of 0.19 nM, whereas it showed a Ki value of 170 nM in rat striatal A2A receptors labelled with [3H]-2-[p-(2-carboxyethyl)-phenethylamino]-5'-N-ethylcarboxamidoad enosine (CGS21680), indicating 890 fold A1 receptor selectivity versus the A2A receptor. KW-3902 at 10 microM showed no effect on recombinant rat A3 receptors expressed on CHO cells. 3. Saturation studies with [3H]-KW-3902 revealed that it bound with high affinity (Kd = 77 pM) and limited capacity (Bmax = 470 fmol mg-1 of protein) to a single class of recognition sites. A high positive correlation was observed between the pharmacological profile of adenosine ligands inhibiting the binding of [3H]-KW-3902 and that of [3H]-CHA. 4. KW-3902 showed potent A1 antagonism against the inhibition of forskolin-induced cyclic AMP accumulation in DDT1 MF-2 cells by the A1-selective agonist, cyclopentyladenosine with a dissociation constant (KB value) of 0.34 nM. KW-3902 antagonized 5'-N-ethylcarboxamidoadenosine-elicited cyclic AMP accumulation via A2B receptors with a KB value of 52 nM. 5. KW-3902 exhibited marked species-dependent differences in the binding affinities. The highest affinity was for the rat A1 receptor (ki = 0.19 nM) and these values for guinea-pig and dog A1 receptors were 1.3 and 10 nM, respectively.

Adenosine↗
PubMed1996

Visual form agnosia in multiple sclerosis.

We report a case of multiple sclerosis with visual form agnosia and callosal syndromes. Initially, the patient's visual recognition of object form was severely disturbed at the perceptual stage, in association with left-sided ideomotor apraxia and agraphia. Magnetic resonance imaging showed large white matter lesions in the bilateral frontal and occipital lobes, the latter extending to the occipitotemporal junction, and widespread corpus callosum lesions. Over the course of one year follow-up, neuropsychological examinations indicated that the patient's visual recognition defects occurred not only at the early substage of form perception, but also at the stage of reproducing the shape of objects from visual memory store. The present case suggests that neural connections between the striate cortex and occipitotemporal visual areas are crucial for both the perceptual and associative stages of visual object recognition.

Agnosia↗
PubMed1996

Renal leiomyoma associated with tuberous sclerosis.

The renal lesions characteristic of tuberous sclerosis are angiomyolipoma and cysts, with the former considered to be more common. Other renal tumors are rarely associated with tuberous sclerosis. Here we present a tuberous sclerosis patient with a renal leiomyoma which was detected incidentally during the investigation of fever of unknown origin.

Adolescent↗
PubMed1996

Multimodal evoked potentials in Alzheimer's disease and Binswanger's disease.

Somatosensory evoked potentials (SEPs), brainstem auditory evoked potentials (BAEPs), visual evoked potentials (VEPs), and auditory event-related potentials (ERPs) were studied in 15 patients with Alzheimer's disease (AD), eight patients with Binswanger's disease (BD), and 15 normal subjects. Patients with BD showed significant prolongation of the interpeak latency between N13 and N20 (N13-N20) and N20-P40 of SEPs as compared with the normal controls, whereas patients with AD only demonstrated significant prolongation of N20-P40. The interpeak latency between waves I and V of BAEPs in patients with both AD and BD was significantly longer than that of controls. There were no significant differences in P100 latency of VEPs among these three groups. Both groups with dementia showed significant prolongation of N200 and P300 latencies of ERPs compared with normal controls. In addition, patients with AD showed significant prolongation of P200 latency. We conclude that these two dementing diseases have different electrophysiologic features that may be related to their underlying pathogenetic mechanisms. Furthermore, the measurement of multimodal evoked potentials may be helpful in the differential diagnosis of AD and BD.

Aged↗
PubMed1996

[Drug-induced nephrotoxicity].

The incidence of drug-induced nephrotoxicity (DIN) has recently been increasing. Based on developments in molecular biology and cell biology, cultured cells have become a very useful tool for investigating DIN. Especially, the immortalized cell lines derived from well-defined nephron segments are ideal for such studies. As indicators to detect DIN, myosin light chain phosphorylation in glomerular mesangial cells, enzymes of proximal tubule origin such as glycine-amidinotransferase, cytosolic free calcium concentration and intracellular ATP content may be useful. The involvement of nitric oxide and heat shock protein in DIN has been reported. Therapeutic effects of growth factors such as HGF or EGF for DIN have been identified. The direct evidence for the involvement of reactive oxygen species and the molecular basis for redox regulation in DIN is required. Cisplatin has been shown to induce apoptosis, and the role of apoptosis in DIN remains to be further clarified. Thus, in parallel with in vivo studies, cultured cells provide an opportunity for clarifying the intracellular mechanism for DIN more precisely and establishing an efficient screening system to develop drugs to prevent DIN.

Amidinotransferases↗
PubMed1996

Histochemical, lectin-histochemical and morphometrical characteristics of intestinal goblet cells of germfree and conventional mice.

Histochemical, lectin-histochemical and morphometrical studies were carried out on intestinal goblet cells of 8-week-old germfree (GF) and conventional (CV) mice of the BALB/c strain. Except for the reactivity of cecal goblet cells to Dolichos biflorus agglutinin (DBA) and Ulex europeus-I agglutinin (UEA-I), there was no difference between GF and CV mice in histochemical and lectin-histochemical properties. In the cecal mucosa, DBA stained the goblet cells strongly in CV mice but not in GF mice and UEA-I stained the goblet cells strongly in the lower part of crypts in CV mice but only faintly in GF mice. These findings suggest that terminal residues of cecal goblet cell mucin were different in GF and CV mice. Morphometrically, cecal goblet cells were fewer in number and smaller in size in GF mice than in CV mice. In addition, high iron diamine-alcian blue staining made a very clear border between the cecum and colon, because cecal goblet cells were exclusively positive for sulfomucin and colonic goblet cells were predominantly positive for sialomucin.

Alcian Blue↗
PubMed1996

Variation in serum creatine phosphokinase activity as indicated in two-phase EMC-D virus-induced myocarditis.

In this study, myocardial damage in the D-variant of encephalomyocarditis (EMC-D) virus-induced myocarditis has been investigated consecutively by measuring serum creatine phosphokinase (CPK) activity. CPK activity in 8 week-old male BALB/cAJcl mice inoculated with EMC-D virus increased to a peak at 4 or 5 days postinoculation (DPI) and then gradually decreased. The CPK activity rose again after 7 DPI until it reached a second peak. In view of the kinetics of CPK activity, two-phase (early and late phase) myocardial damage in EMC virus infection were considered. In the late phase, an increase in cellular infiltration in the myocardium and a decrease in viral titer in the heart were observed. It was therefore suspected that the increase in CPK in the late phase may be caused by cellular infiltration, but not by viral replication. In our results, we suggested that a serial measurement of serum CPK activity might be a useful method for throwing more light on the myocardial damage caused by the autoimmune response. We also used a pathological (TUNEL) method to detect apoptotic cells and some apoptotic myocytes in the myocardium in late phase EMC virus-induced myocarditis.

Animals↗