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Biomedical subjects

H Muto

Publications and source records attributed to H Muto.

At least 73 records · Page 4Linked to original sources
PubMed1991

Rapid changes in concentrations of essential elements in organs of rats exposed to methylmercury chloride and mercuric chloride as shown by simultaneous multielemental analysis.

An in vivo study of rats given a dominant lethal dose of methylmercury chloride (MMC) or mercuric chloride (HgCl2) was conducted to elucidate the rapid biotransformation of essential elements. The elements were measured by inductively coupled plasma atomic emission spectrometry. For the rat brain Zn concentrations were higher in the MMC group than in the HgCl2 and control groups. The highest Cu concentration was found in HgCl2 dosed rat liver. For the rat kidney the highest Zn concentration was seen in the MMC group. From principal component analysis on the time dependent behaviour of each element in rat organs, characteristics specific to Cu in the liver and kidney and Mn in the brain were found after exposure to HgCl2 and Ca and Zn in the brain after exposure to MMC.

Animals↗
PubMed1990

The epithelium lining the orifice of the laryngeal gland of the Suncus murinus, with special reference to the "intermediate epithelium (Nakano)".

In the lateral wall of the laryngeal ventricle of the Suncus murinus, only a few excretory ducts of the laryngeal gland opened that drained the extensive lobular system. The ducts opened into the "intermediate epithelium (NAKANO, T.: Acta Anat. 127: 22-47, 1986)," which lined the transitional zone between the ciliated columnar epithelium and the stratified squamous one, and that showed gradations ranging from the ciliated stratified low-columnar through stratified cuboidal to stratified squamous type. The orifice of the laryngeal gland was relatively wide for the size of the animal and, therefore, the epithelium within the orifice was clearly observed by use of SEM. As the number of the ciliated cells decreased in the intermediate epithelium surrounding the orifice, the ciliated cells within the orifice reduced in number. Considering from these findings, it is suggested that the epithelium within the orifice has morphologically close resemblance to, and is influenced by, the epithelium surrounding the orifice.

Animals↗
PubMed1990

Identification of lactotropes (PRL cells), somatotropes (GH cells), corticotropes (ACTH cells) and thyrotropes (TSH cells) in the pituitary gland of the musk shrew, Suncus murinus L. (Insectivora), by immunohistochemistry.

By means of immunohistochemistry, lactotropes, somatotropes, corticotropes and thyrotropes in the pituitary of the male musk shrew, Suncus murinus L., were identified at the electron-microscopic level. Lactotropes were classified into three types: type I containing large (200-450 nm in diameter) round secretory granules, type II with medium-sized (150-250 nm in diameter) ones and type III with small (50-150 nm in diameter) ones. Somatotropes were also classified into type I somatotropes that contain large (450 nm in diameter) spherical secretory granules and type II somatotropes containing comparatively small (300 nm in diameter) round granules. Both type I and II somatotropes were small and sometimes contained rod-shaped granules. Corticotropes were round or oval cells with round secretory granules in various densities and sizes (150-500 nm in diameter) scattered all over the cytoplasm. Thyrotropes were angular or polyhedral cells containing electron-transparent round secretory granules (200-300 nm in diameter) and large irregularly shaped granules with a maximum diameter of about 1,500 nm. Each type of the cells may be distinguished by its respective ultrastructural characteristics alone without the aid of immunohistochemistry.

Adrenocorticotropic Hormone↗
PubMed1990

The intermediate epithelium lining the nasopharynx of the Suncus murinus.

In the adult Suncus murinus, the rostral part of the nasopharynx is lined with the ciliated columnar epithelium continuing from the nasal cavity, while the laryngopharynx with the stratified squamous epithelium; i.e., the epithelium lining the caudal part of the nasopharynx forms the transitional zone between the ciliated columnar epithelium and the stratified squamous one. The epithelium shows gradations ranging from ciliated stratified low-columnar through stratified cuboidal to stratified squamous type. It is suggested that the epithelium is identical with the "intermediate epithelium (Nakano, 1986)".

Animals↗
PubMed1990

Postnatal transformation and location of mitoses in the epithelium lining the mouse vomeronasal organ.

The structure and the postnatal transformation of the epithelium lining the vomeronasal organ of the mouse was observed. The medial wall of the middle segment of the organ was lined with the sensory epithelium similar to the olfactory epithelium, and was not undergone any transformation in the postnatal life. The lateral wall of the middle segment and the entire lumen of the rostral segment were covered with the stratified cuboidal epithelium in the newborn mouse. The stratified cuboidal epithelium transformed into the ciliated columnar epithelium with advancing ages, excepting in the vomeronasal duct where the epithelium changed into the stratified squamous one. In the mouse aged between 4 and 10 days, mitotic figures were observed not only in the boundary between the sensory epithelium and the ciliated columnar one in the middle segment, but also in the rostral segment of which the entire lumen was covered with the ciliated columnar epithelium.

Animals↗
PubMed1990

Characteristic features in the "laryngotrachea" of Suncus murinus.

In the larynx of the Suncus murinus (house musk shrew), the cricoid cartilage was situated laterally to and overlapped with the 1st, the 2nd, and a part of the 3rd tracheal cartilages. The term "laryngotrachea" was used for the region maintained by both the cricoid cartilage and the tracheal ones. It is suggested that the condition of the cartilages in Suncus laryngotrachea is the most primitive condition in mammals. In the dorsal wall, just caudal to the plate of the cricoid cartilage and dorsal to the 3rd tracheal cartilage, there existed the "L-shaped cartilage" (named by the authors).

Animals↗
PubMed1990

[Effect of mercuric chloride on phospholipid peroxidation in rat].

Individual molecular species of mercuric chloride induced phospholipid peroxide formed in rat brain, liver and kidney were determined using the multi-channel UV-high-performance liquid chromatography (HPLC) combined with potentiometric determination. Mercuric chloride (0.5 mg/kg/day) was administered subcutaneously to rats for 3 days. In accordance with a specified time schedule following administration (0.5, 1, 3 and 5 days), rats were decapitated and the phospholipids of brains, livers and kidneys were extracted and purified. The samples were then injected into the HPLC and the ratio (235 nm/203 nm) of peak area of each phospholipid was calculated. The peroxide value of each sample was determined using the calibration curve of the auto-oxidized standard phospholipids which were analyzed by both potentiometric determination and UV HPLC. Kidney phospholipid peroxides were easier induced than those in other organs reached their maximum peak (20.5 meq./kg) at 1 day after initial administration. Phospholipid peroxides in kidney and brain showed similar movement, while those in liver showed their maximum peak 3 days later. Of the phospholipids, phosphatidylserine and phosphatidylethanolamine seemed to be more susceptible to lipid peroxidation induced by mercuric chloride, the common feature of these two phospholipids being that both of them have primary amine group(s) on their polary heads and both are located on the cytosolic side of cell membrane. These results may be explained by mechanisms that relate to the interaction between mercurials and cell membranes or that between mercurials and primary amine groups of phospholipids. Further study is necessary to clarify the specific mechanisms involved in the induction of lipid peroxidation by mercurials and the interaction of mercurials with phospholipids.

Animals↗
PubMed1989

A case of gallbladder cancer manifesting chylous ascites and chylothorax.

A case of gallbladder cancer manifesting both chylous ascites and chylothorax was reported. A 66-year-old man was hospitalized with milky ascites. The patient was diagnosed as having gallbladder cancer based on findings of endoscopic retrograde cholangiopancreatography (ERCP) and celiac angiography. The diagnosis of chylous ascites was confirmed by the presence of microscopically visible free fat and the biochemical analysis of the fluid. The patient also gradually developed chylous thoracic effusion. Autopsy revealed lymphogenous metastasis in multiple retroperitoneal and mediastinal nodes. Chylothorax and chyloperitoneum are relatively rare. Only five cases have been reported in Japan that manifested both conditions.

Adenocarcinoma↗
PubMed1989

The intermediate epithelium lining the larynx of the Suncus murinus.

In the larynx of the Suncus murinus the stratified squamous epithelium lines the tip of the caudal surface of the epiglottis and the region close to the vocal process of the arytenoid cartilage, while the ciliated columnar epithelium is located in the laryngeal sac and the dorsal part of the vocal fold. Further, in the transitional zone between the stratified squamous epithelium and the ciliated columnar one there exists the epithelium which shows gradations ranging from stratified squamous through stratified cuboidal to ciliated stratified low-columnar type. It is suggested that the epithelium lining the transitional zone is identical with the "intermediate epithelium" in the mouse nasopharynx and larynx.

Animals↗
PubMed1989

Scanning electron microscopic observation on the distal part of the male urethra of the mouse.

In the proximal end of the navicular fossa, the stratified columnar epithelium lining the spongy part of the urethra abruptly changes into the stratified squamous one, presenting a sharp demarcation. It is considered that the junction between these 2 epithelia corresponds to the former site of the junction of the entoderm and ectoderm. The width of the microridges in the distal part of the navicular fossa was about doubled compared to that in the proximal part. It is suggested that the epithelium in the distal part is keratinized, while that in the proximal part is nonkeratinized.

Animals↗
PubMed1989

Isolation and identification of embryo-derived platelet-activating factor in mice.

We isolated a platelet-activating factor (PAF) derived from mouse embryos and identified it by bioassay utilizing washed rabbit platelets. We also tried further characterization of the factor by high-performance liquid chromatography (HPLC) and electron-impact mass spectrometry (EI-MS). 1. In the thin-layer chromatography (TLC) of the medium after a two day culture of 30 embryos at the two-cell stage, no obvious spot appeared at the site of 1-O-acetyl-2-O-alkyl-SN-glyceryl-3-phosphocholine (AGEPC). But a small, pale spot appeared at the site of lyso-AGEPC. 2. A remarkable aggregation activity was present at the site of the Rf and appearance time that was almost the same as for AGEPC in both TLC and HPLC. However, detection of the substance by UV absorption (203nm) in HPLC was unsuccessful. 3. The PAF activity shown in the culture medium was suspected to be 10(-10 - 10(-11) M/embryo and it was not inhibited by pretreatment with indomethacin and ADP scavenger. 4. Embryo-derived PAF had an HPLC appearance time 1-2 min. longer than that of synthetic AGEPC (C16). EI mass spectrum of embryo-derived PAF was partly inconsistent with that of synthetic AGEPC (C16). These results confirm the evidence of PAF release from mouse embryos and show the possibility that a far greater amount of its lyso-derivative is present in the culture medium. Embryo-derived PAF is presumed to be AGEPC or a substance resembling AGEPC in its chemical structure and some structural difference may exist between embryo-derived PAF and synthetic AGEPC (C16).

Animals↗
PubMed1988

Increased parietal cell responsiveness to tetragastrin in patients with recurrent duodenal ulcer.

To clarify the contributive factors in the recurrence of duodenal ulcer, the present study was carried out on 65 male patients with active duodenal ulcers and 20 healthy male subjects. After having verified that the ulcer had healed, gastric acid secretory responses to graded doses of tetragastrin from 62.5 to 16,000 ng/kg/hr were investigated using a logarithmic transformation model. Several clinical features were also investigated. The patients were divided into three groups based on the later endoscopic follow-up study for two years. The early-recurrent group included 16 patients with recurrence occurring within three months. The late-recurrent group included 25 with recurrence occurring after three months. The nonrecurrent group included 24 patients without recurrences during the follow-up period. The 20 healthy male subjects were defined as a control group. The results were as follows: (1) Significant differences were not discerned either in basal and peak acid outputs between the three patients groups. (2) The ED50 value for tetragastrin was lower in the early-recurrent group than in the other three groups. (3) The early-recurrent group showed a higher percentage of smokers than the other patient groups. These results suggest that smoking and increased parietal cell responsiveness correlates strongly with duodenal ulcer recurrence.

Adult↗
PubMed1988

Structure and postnatal transformation of the intermediate epithelium lining the mouse nasopalatine duct.

In the epithelium lining the nasopalatine duct of the infant mouse, a transitional zone between the stratified squamous epithelium and the ciliated columnar one can be observed. The epithelium lining the transitional zone shows gradations ranging from the stratified squamous through the stratified cuboidal to the ciliated stratified low-columnar type, and gradually transforms into the stratified squamous epithelium with advancing ages. In the adult mouse, the nasopalatine duct is lined with the stratified squamous epithelium throughout up to the vicinity of the nasal cavity, and changes abruptly into the ciliated columnar epithelium lining the nasal cavity. It is suggested that the epithelium lining the transitional zone is identical with the 'intermediate epithelium' in the mouse nasopharynx and epiglottis.

Animals↗
PubMed1988

Anatomical studies in the hyoid region of the mouse in term of evolutional importance.

The mouse hyoid region was studied in detail in term of its evolutional importance. A pair of small pyramidal-shaped "epiphyseal cornua" wedged between the body and the caudal cornua. It is suggested that the epiphyseal cornu is an independent element of the hyoid bone, and that it is not homologous with the typical hypohyal in other mammals. Just ventral of the tympanic bulla, there was a stylohyal, on which the "paroccipito-styloideus" and "paroccipitostylohyoideus" muscles (appellations by the authors) were attached. Ossification of the hyoid bone began at the attachments of the hyoid muscles, which acted synergically in tongue movement or swallowing. It is suggested that the ossification is triggered by the mechanical stress of the muscles in tongue movement or swallowing.

Animals↗
PubMed1987

Separation, amino-terminal sequence and cell-free synthesis of the smallest subunit of sweet potato cytochrome c oxidase.

The smallest subunit (V) of sweet potato cytochrome c oxidase was separated into three polypeptides, Va, Vb and Vc with different molecular masses (7.4 kDa, 6.8 kDa and 6.2 kDa respectively) by highly resolving sodium dodecylsulfate polyacrylamide gel electrophoresis. Antibody against subunit V reacted specifically with the polypeptide Vc. When polyadenylated mRNA from sweet potato root tissue was translated in a wheat germ cell-free system, the smallest subunit (Vc) of the polypeptides was synthesized to the same size as the mature form, which suggests that the mature subunit retains the signal for import into mitochondria. Within the N-terminal first 25 amino acids there is a stretch of 16 non-polar residues, periodically linked by basic residues, which might form an amphiphilic helix as the targeting signal.

Amino Acid Sequence↗
PubMed1987

A case of homicidal intoxication by chloropicrin.

An 18-year-old girl and her boyfriend were sprayed with toxic chemicals from the left front door of their parked car. The girl died of intoxication about 4 h later. The main findings of postmortem examination were spotty discolorations on her skin and severe pulmonary edema. The unknown chemical was identified as chloropicrin by gas-liquid chromatography and gas chromatography-mass spectrometry of her lung and on samples from the car's console box, cassette tape case, and floor mat, all of which were wet with chemicals. The content of chloropicrin in her lung was calculated at 1.6 ng/g of wet weight.

Adolescent↗