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Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 361 records · Page 20Linked to original sources
PubMed1997

Induction of apoptotic cell death by direct-current treatment in human leukemic cell lines.

Exposure of human leukemic cell lines (HL-60, ML-1, U-937, MOLT-4, EOL-1) to short direct-current (d.c.) treatment induced apoptotic cell death, characterized by cell shrinkage and nuclear and internucleosomal DNA fragmentation. On the other hand, human peripheral blood lymphocytes and polymorphonuclear cells were relatively resistant to d.c. treatment, and did not show any clear nuclear and DNA fragmentation. The effect of d.c. was slightly reduced by calcium depletion, but was not significantly affected by catalase or by superoxide dismutase. The present data suggest that previously reported tumor regression activities of d.c. treatment might be due, at least in part, to its apoptosis-inducing activity.

Antioxidants↗
PubMed1997

Effects of vagal and carotid chemoreceptor afferents on the frequency and pattern of spontaneous augmented breaths in rabbits.

We investigated the effects of vagal afferents and carotid chemoreceptors on the frequency and pattern of spontaneous augmented breaths in anesthetized rabbits by analyzing the changes in the phrenic nerve discharge. Blockade of vagal C-fiber conduction by capsaicin treatment greatly reduced the frequency of spontaneous augmented breaths but had no significant effect on the pattern of the augmented breaths. Inhalation of sulfur dioxide, which abolished the Hering-Breuer inflation reflex, suppressed the frequency of spontaneous augmented breaths but did not significantly alter the pattern of the augmented breaths. Carotid sinus denervation diminished both the frequency and amplitude of spontaneous augmented breaths. The occurrence of spontaneous augmented breaths was not observed in rabbits after bilateral vagotomy. In other experiments we examined the relationship between rapidly adapting pulmonary stretch receptors (RARs) and dynamic lung compliance during the spontaneous augmented breath. The stimulation of RARs occurred at the first phase of spontaneous augmented breaths, and augmentation of transpulmonary pressure seen at the second phase coincided with vigorous stimulation of the receptor activity. These results suggest that spontaneous augmented breaths may be mediated by the summation of several facilitatory inputs from vagal and carotid chemoreceptor afferents.

Action Potentials↗
PubMed1997

Predictors of the progression of diabetic nephropathy and the beneficial effect of angiotensin-converting enzyme inhibitors in NIDDM patients.

A progressive decline in glomerular function occurs in diabetic nephropathy. The predictive effects of progression promoters were examined in 182 non-insulin-dependent diabetic patients from a baseline serum creatinine concentration of 133 mumol/l. During a total of 605 person-years follow-up, 107 patients developed end-stage renal failure requiring dialysis. The rate of decline of renal function was highly variable. Urinary protein excretion was the strongest predictor correlated to the rate of decline, followed by diastolic and systolic blood pressure, total cholesterol and platelet count, while the protective effects were seen in serum albumin and haematocrit. Adjustment for urinary protein excretion revealed that diastolic blood pressure, familial predisposition to hypertension, serum albumin, and smoking were independent significant predictors. Angiotensin converting enzyme inhibitors (ACE-I) significantly retarded the development of end-stage renal failure compared to antihypertensives other than ACE-I (mostly nifedipine), and the effect was evident particularly in patients with proteinuria below the median (2.5 g/24 h) (presumably those who responded to ACE-I). A complex effect of proteinuria in association with blood pressure elevation, familial predisposition to hypertension, hypoalbuminaemia, and smoking may play an important role in the progression of nephropathy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Cisplatin-induced apoptosis of immortalized mouse proximal tubule cells is mediated by interleukin-1 beta converting enzyme (ICE) family of proteases but inhibited by overexpression of Bcl-2.

Cisplatin is known to induce serious renal damage including acute renal failure, the major site of renal injury appears to be localized to the third segment of the proximal tubule (S3). Apoptosis occurs during a variety of acute injuries to tubule cell. The purpose of this study was to determine whether cisplatin induces apoptosis of immortalized mouse S3 cells, and to define the intracellular pathways leading to cell death. S3 cells exposed to cisplatin exhibited biochemical, morphological, and flow cytometric changes characteristic of apoptosis associated with slight necrosis. Cisplatin-induced apoptosis could be inhibited by overexpression of crmA, a cowpox virus gene, of which the product is known to suppress activities of the interleukin-1 beta converting enzyme (ICE) family proteases. On the other hand, overexpression of bcl-2, an antiapoptotic oncogene, rendered S3 cells partially resistant to cisplatin. These results indicate that cisplatin-induced proximal tubule damage is associated with apoptosis, which is positively modulated by the ICE family of proteases and negatively by the product of bcl-2.

Animals↗
PubMed1997

Distribution of the neural cell adhesion molecule (NCAM) during pre- and postnatal development of mouse incisors.

Developmental changes in the distribution of the neural cell adhesion molecule (NCAM) were investigated in mouse incisors by means of the indirect immunofluorescence method. During the prenatal stages of development, NCAM was predominantly found in the dental follicle, but not in the dental papilla; the results were analogous to the distribution of NCAM during molar development. After birth, the expression of NCAM continued in the tissue between the enamel organ and the alveolar bone on the labial aspect. In contrast, the follicular tissue covering the lingual aspect of the incisor gradually lost NCAM immunoreactivity from its outer zone as it differentiated into the highly organized periodontal ligament. The intermediate zone of the ligament continued to express NCAM-immunoreactivity even in mice of 6 weeks of age. This pattern of NCAM expression was different from that found in molar teeth, where the organized peridontal ligament was NCAM-negative. The dental pulp, in which we previously reported that an NCAM-positive area appeared at later stages of molar tooth development, did not express NCAM immunoreactivity even at the latest stage of development covered in this study. These differences in the distribution of NCAM between the incisors and the molars might be related to the fact that rodent incisors continue to grow throughout the life of the animal.

Aging↗
PubMed1997

Effect of denervation on lymphocytes and dendritic cells in the rat circumvallate and foliate papillae.

The distribution of dendritic (Langerhans) cells and lymphocytes in rat circumvallate and foliate papillae was examined by immunohistochemistry and electron microscopy. Light microscopic immunohistochemistry using anti-OX62 antibody, which recognizes both gammadelta T lymphocytes and dendritic cells, showed that many OX62-immunoreactive cells had invaded into the trench wall epithelium from the connective tissue at 6 days after sectioning of the glossopharyngeal nerves. The presence of OX62-immunoreactive cells in the epithelium was observed up to 17 days after the denervation, by which time the taste buds had disappeared from the trench wall. The OX62-positive cells were again observed in the connective tissue at 24 and 40 days when taste buds regenerated. The local circulation of OX62-positive cells between the epithelium and connective tissue is suggested. Most of the OX62-positive-cells in the epithelium of circumvallate and foliate papillae were suggested to be gammadelta T cells, since they were round or spindle-shaped. Electron micrographs of OX62-positive cells also indicated that they were lymphocytes. Furthermore, they expressed CD3 but lacked CD4 and CD8 surface markers. A few dendritic cells, which reacted with anti-OX6 antibody, were observed in the circumvallate and foliate papillae in the control and denervated animals, and they were irregular in shape with long cytoplasmic processes. Electron micrographs taken at 6 days showed that the dendritic cells, which were characterized by the presence of Birbeck granules in the cytoplasm, were in contact with lymphocytes. The finding suggests that gammadelta T lymphocytes and dendritic cells in the rat circumvallate and foliate papillae interact with each other to respond to changes such as the presence or absence of taste buds in the epithelium.

Animals↗
PubMed1997

Effect of glutathione-modulating compounds on hydrogen-peroxide-induced cytotoxicity in human glioblastoma and glioma cell lines.

The relation between the intracellular glutathione (GSH) concentration and hydrogen-peroxide(H2O2)-induced cytotoxicity was investigated. The intracellular GSH concentration in human glioblastoma (T98G, U87MG) and glioma (KG1C) cell lines was one or two orders of magnitude higher than that in a human myelogenous leukemic cell line (HL-60), which showed higher sensitivity to H2O2. Pretreatment of these cell lines with L-buthionine-[S,R]-sulfoximine, which significantly reduced the intracellular GSH concentration, increased their sensitivity against H2O2, whereas pretreatment with N-acetyl-L-cysteine, which did not significantly change the intracellular GSH concentration, only marginally protected the cells from the cytotoxic effect of H2O2. The results suggest that drug sensitivity of tumor cells can be modified by glutathione-modulating compounds.

Acetylcysteine↗
PubMed1997

Respiratory failure in nemaline myopathy.

Four patients with nemaline myopathy, 1 with the severe infantile form and 3 with the benign congenital (classical) form, exhibited significant respiratory problems. In the patient with the severe infantile form, respiratory failure paralleled the generalized muscle weakness, whereas the 3 patients with the benign infantile form suddenly developed respiratory failure while still ambulant. Polysomnographic studies performed on 2 patients revealed that apnea or irregular thoracic movements occurred only during rapid eye movement sleep, when hypercapnia was also demonstrated on serial transcutaneous partial O2 and partial CO2 monitoring. A discrepancy between motor ability and respiratory involvement probably is not uncommon in patients with the moderate congenital form of nemaline myopathy. Clinicians must always be alert to respiratory failure when monitoring patients with nemaline myopathy.

Adolescent↗
PubMed1997

Effect on an iron-chelator on ascorbate-induced cytotoxicity.

We investigated the effect of deferoxamine mesylate (DFO), an iron chelator, to test whether ascorbate-induced cytotoxicity is due to iron-catalyzed oxidation. Exposing human promyelocytic leukemic HL-60 cells to either sodium ascorbate or ascorbic acid for 1 h resulted in the progressive production of apoptotic cells characterized by cell shrinkage, as well as nuclear and internucleosomal DNA fragmentation. The addition of micromolar to millimolar concentrations of DFO during the 1-h exposure did not inhibit, but rather enhanced the ascorbate-induced apoptosis in both regular and serum-free RPMI1640 medium. However, a higher concentration of serum significantly inhibited the ascorbate-induced cytotoxicity. In contrast, the cytotoxic activity of ascorbate against T98G human glioblastoma cells was enhanced or reduced by micromolar and millimolar concentrations of DFO, respectively. Ascorbate significantly increased the oxidation potential in the culture medium, and the pro-oxidant action of ascorbate was further augmented by the presence of the cells. DFO did not significantly affect the ascorbyl radical intensity and only slightly reduced the ascorbate-elevated oxidation potential. These data demonstrated that ascorbate can induce cytotoxicity even in iron-deficient medium.

Apoptosis↗
PubMed1997

Galactosamine-induced apoptosis in the primary mouse hepatocyte cultures.

Galactosamine (GalN)-induced apoptosis was investigated in cultured hepatocytes from mice. The percentage of fragmented DNA measured by the ELISA method increased in a concentration-dependent manner from the very early stage, i.e. 0.5 hrs, after GalN-exposure. In addition, a ladder-like fragmentation pattern by agarose gel electrophoresis appeared first at 3 hr-exposure to 20 mM GalN, at 6 hr-exposure to 10 mM GalN and at 12 hr-exposure to 5 mM GalN, respectively. On the other hand, cytotoxicity indicated by leakage of lactate dehydrogenase from cultured hepatocytes to culture medium was first detected at 24 hrs after GalN-treatment. Morphologically, formation of blebs and apoptotic bodies was observed from 12 hr-exposure to 20 mM GalN and from 24 hr-exposure to 10 mM GalN, respectively. Thus GalN could induce apoptosis in primary hepatocyte cultures from mice.

Animals↗
PubMed1997

An investigation into the distributive pattern, classification and functional role of the conical papillae on the posterodorsal surface of the cat tongue using SEM.

In order to examine the relationship between their distributive patterns, classification and functional roles, three-dimensional structures in the microvascular network of the conical papillae (CoP) on the posterior third of the central dorsal surface of the cat tongue were observed by the corrosion cast method under a scanning electron microscope (SEM). CoP can be classified into two types: small conical papillae (SCoP) and large conical papillae (LCoP), according to their shape, size and distributive pattern. On the posterior third of the central dorsal surface of the tongue, SCoPs are arranged in the form of six-eight straight lines running regularly from the posterior third of the central zone towards the pharynx. LCoPs are also arranged in the form of a V, with the point directed posteriorly, in oblique lines running in an orderly fashion from both the antero-peripheral zones to the central zone. To summarize CoPs play an important role in the drinking of milk and water, after mixing the food with saliva, in the transport of the food mass towards the pharynx and in swallowing it.

Animals↗
PubMed1997

Microvascular fin-like structure of the foliate papillae of the rabbit tongue using scanning electron microscopic specimens.

Although many morphological studies have been undertaken on the lingual papillae of the rabbit tongue, relatively few have dealt with the microvascular structure and classification of the foliate papillae (FoP) by means of microvascular cast specimens (MVCS) and using scanning electron microscopy (SEM). For the present study, a three dimensional observation and classification was carried out by SEM. The morphological characteristics of the outer frame structure were observed by means of MVCS of FoP which were located on both posteroperipheral parts of the tongue. They showed a bead-like appearance and consisted of 14-18 transverse and slightly bent fin-like structures, running from the dorsal surface to both peripheral sides symmetrically. These are effectively increased on the surface areas and play the functional role of receiving the taste sense. FoPs can be classified into three types: type I (14 fins), type II (16 fins), type III (18 fins) according to the fin numbers.

Animals↗
PubMed1997

Angioarchitectural classification of the fungiform papillae on the dorsal surface of the bullfrog tongue.

In this study, the three-dimensional anatomy of the microvascular structure of fungiform papillae (FuP) on the dorsal surface of the bullfrog tongue has been investigated using scanning electron microscopy (SEM), and angioarchitectural classification has been carried out by means of the capillary loop (L. s) and intra-bridge structure (I. b). FuP from 30 sound bullfrog tongues were used. The following research methods were applied: SEM observation on microvascular cast specimens (MVCS) of bullfrog tongue's FuP were injected with synthetic resin (Mercox). Observation of MVSC showed that the bullfrog tongue FuP consisted of an ascending branch (A. b), L. s, I. b and a descending branch (D. b). Based upon SEM observations of MVCS, FuP can be classified into four types: A, B, C, D types according to A. b, L. s, I. b and D. b. A-type (none I. b) formed from A. b, L. s, D. b only and with no I. b. B-type (one I. b) consisted of A. b, L. s, D. b and one I. b. C-type (two I. b) were composed of A. b, L. s, D. b and two I. b. D-type (three I. b) were composed of A. b, L. s, D. b and three I. b, A. b, L. s, I. b and D. b on each. A, B, C, D types were all same thickness.

Animals↗
PubMed1997

Angioarchitectural structure of the fungiform papillae on the anterodorsal surface of the rat tongue.

To ascertain whether the microvascular morphological differences of fungiform papillae (FuP) on the anterodorsal surface of the rat tongue are locationally and functionally related, this study aimed at examining and comparing, in greater detail, the comparative morphological characteristics of FuP. FuP were sporadically and consistently scattered among numerous filiform papillae (FiP) in three parts: the apical, central and in front of the intermolar eminence on the anterodorsal surface. We studied these by means of the microvascular cast specimen (MVCS) of FuP using scanning electron microscopy (SEM). The results obtained in this study showed that in all three parts on the anterodorsal region, the capillary bed of FuP presented as a netbasket-like and cylindrical figure with a central hole consisting of 4-5 horizontal rings of several ascending and descending roots. FuP in the central part on the anterodorsal region were relatively larger in size and more cylindrical in shape than those of both the other parts, and they play the leading part as sensory organs for the taste sense and were regarded as taste receptive organs.

Animals↗
PubMed1997

Functional role of V form distribution seen in microvascular cast specimens of the filiform and fungiform papillae on the posterior central dorsal surface of the cat tongue.

The relationship between the functional role and three-dimensional structures of the microvascular network of the filiform papillae (FiP) and fungiform papillae (FuP) on the posterior central surface of 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 (Ojima and Lowe 1995), and FuP, found to be distributed sporadically among FiP (I-V), into four types; types I-IV (Ojima et al. 1996 b) according to the shape and size of the main process (MP) and the number of the accessory processes (AP). Each of the types I-V of FiP were arranged in the form of a V as oblique lines running in an orderly and geometrical fashion from the posterior central zone to the anterior peripheral zone in both directions. Each of the types I-IV of FuP were scattered throughout the line of FiPs arranged in the form of a V, the point of which is directed towards the pharynx. FiPs 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 FuPs is considered to be a modified form of the MP of FiP of the cat tongue function (Ojima et al. 1996 c) as part of a sense organ for taste.

Animals↗
PubMed1997

Angioarchitectural structure of the fungiform papillae on rabbit tongue anterodorsal surface.

The relationships between the functional and morphological characteristics and the positional difference of the microvascular cast specimen (MVCS) of the fungiform papillae (FuP) on the antero-dorsal surface of the rabbit tongue were examined and compared using a scanning electron microscope (SEM). The sporadic FuPs scattered among the numerous small filiform papillae (SfP) were found to be distributed irregularly over the antero-dorsal surface. FuPs consisted of the ascending and descending capillary loops, forming margins of the central opening at the top of FuP. They resembled flower-like configurations (carnations), the petals of which ranged from eight to twelve, and they were larger in width and more complex in shape than SfPs with morphological differences. FuPs can be classified into three types: type I (consisting of eight petals), type II (ten petals), type III (twelve petals) according to the shape of FuP, and to the petal number of the flower-like aspect on the eight points of MVCS of FuPs observed by SEM. These results suggest that the petals of the ascending and descending capillary loops of FuP expanded the flower-like figure, increased in the surface areas and effectively play a role in receiving the sense of taste.

Animals↗
PubMed1997

Numerical variation and distributive pattern on microvascular cast specimens of vallate papillae in the crossbred Japanese cat tongue.

In order to examine in detail the numerical variation and distributive pattern of vallate papillae (VaP) on the lingual posterior dorsal surface of the crossbred Japanese cat tongue, macroscopic, stereoscopic and scanning electron microscopic studies by means of a microvascular cast specimen (MVCS) were carried out under the scanning electron microscope (SEM). Regardless of sex, there were 4-8 VaPs in number, with an average of 6, forming 2-4 pairs arranged by type which could be observed symmetrically or asymmetrically on both sides of the posterior dorsal region of the tongue surface. The results of this study showed that the distributive pattern of VaP can be classified into six forms: typical forms I (2 left and 2 right), II (3:3) and III (4:4); and forms IV (2:3), V (2:4) and VI (3:2) were atypical. It seems that there is every probability that statistically another atypical form (3:4), (4:2), (4:3) will appear in the future. Nevertheless, in a large number of studies on the lingual papillae of the cat tongue, 8 VaPs arranged in pairs by type have been found (form III (4:4)) has not yet been reported in the crossbred Japanese cat tongue.

Animals↗