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Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 379 records · Page 21Linked to original sources
PubMed1989

Histochemical localization of calcium in the enamel organ of rat incisors in early-stage amelogenesis.

The localization of calcium in the enamel organ of rapidly-frozen, freeze-substituted rat incisors in early-stage amelogenesis was examined by a histochemical calcium-staining method. In secretory ameloblasts, glyoxal bis(2-hydroxyanil) (GBHA) staining revealed intense red reactions in mitochondria and tubulovesicular structures located throughout the cytoplasm, while no reaction was seen in the nucleus and cytosol, nor along the plasma membranes of the respective cells. No significant GBHA reaction was observed in the intercellular compartment and other cells of the enamel organ. Some granular reactions were localized in the cells of the adjacent connective tissue. Control tests confirmed the specificity of GBHA reactions for calcium. Thus, the present observations provide histochemical evidence indicating an exclusive localization of calcium in mitochondria and tubulovesicular structures of the secretory ameloblast, and support their contributions to the translocation of calcium from the proximal to the distal pole of the cytoplasm.

Amelogenesis↗
PubMed1989

Role of free radicals and lipid peroxidation in gastric mucosal injury induced by ischemia-reperfusion in rats.

Ischemia and reperfusion are of the greatest importance in the pathology of many diseases. We investigated the roles of oxygen-derived free radicals and lipid peroxidation in gastric mucosal injury, such as spotty and linear hemorrhagic erosions, induced in rats by ischemia-reperfusion. The gastric mucosal injury and the increase in thiobarbituric acid (TBA) reactants in the gastric mucosa induced by ischemia-reperfusion were significantly inhibited by treatment with SOD and catalase. These results suggest that oxygen-derived free radicals and lipid peroxidation play important roles in the pathogenesis of acute gastric mucosal lesions induced by ischemia-reperfusion.

Animals↗
PubMed1989

Physiological significance of mucous neck cell-type mucins in the healing of acetic acid-induced gastric ulcers in rats.

The present study was undertaken to elucidate the role of mucous secreting cells in the healing of acetic acid-induced gastric ulcers in rats. The results indicated that mucous neck cells (MNCs) and their secretions seem to play important roles in the prevention of the expansion of ulceration in the early stage. The reasons are that the surface mucous layer coating the ulcerated surface almost exclusively consists of MNC-type mucins and MNCs increase markedly in the mucosae surrounding ulcers. Transitional type cells containing both MNC-type and chief cell-type granules frequently occurred in this region, although chief cells almost completely disappeared.

Acetates↗
PubMed1989

[Chemoembolization with degradable starch microspheres for liver metastases in colorectal cancer].

Transcatheter chemoembolization using Degradable Starch Microspheres (DSM) was performed in 17 patients with liver metastases of colorectal cancer. Mitomycin C mixed with DSM was injected into the proper hepatic artery. Tumor regression of over 50% was observed in 9 of 17 cases (53%). Elevated serum CEA levels (greater than 10 ng/ml) decreased in 10 of 15 cases (67%). One-year survival rate was 50% in 17 cases. One-year survival rate was 100% in 7 cases with several liver metastases (H2). Abdominal pain occurred in 36%, mostly disappearing within 2 hours. No major side effects such as bone marrow suppression or hepatotoxicity were observed. Our results suggest that chemoembolization using DSM is effective and safe in the treatment of liver metastases from colorectal cancer.

Colorectal Neoplasms↗
PubMed1989

[Role of polymorphonuclear leukocytes and oxygen-derived free radicals in the formation of gastric mucosal lesions induced by platelet-activating factor].

Gastric hemorrhagic erosions were induced by the administration of platelet-activating factor (PAF). Gastric wall blood flow was decreased and thiobarbituric acid (TBA) reactants in the gastric mucosa were increased 10 min after PAF injection. SOD and catalase reduced gastric mucosal lesions and TBA reactants, but had no influence on gastric blood flow. In polymorphonuclear leukocytes (PMN)-depleted rats, gastric mucosal lesions and TBA reactants in the gastric mucosa were reduced and gastric blood flow were increased. PAF induced the superoxide production from rat PMN in a dose dependent manner. These results suggest that oxygen-derived free radicals produced by PMN and lipid peroxidation may play an important role in the pathogenesis of gastric mucosal injury induced by PAF.

Animals↗
PubMed1989

[Chemo-embolization using degradable starch microspheres and regional hyperthermia in unresectable hepatocellular carcinoma].

Antitumor effects and prognosis of the patients with unresectable hepatocellular carcinoma were investigated in the treatment of chemo-embolization using degradable starch microspheres (DSM) and regional hyperthermia. Twenty-six cases were treated with chemo-embolization using DSM alone (Group A) and eighteen cases were treated with combination of chemo-embolization and hyperthermia (Group B). Tumor regression rates over 50% were 42% (11/26) and 56% (10/18) in Group A and Group B, respectively. In the patients with tumors over 7 cm in diameter, no favorable response was obtained in Group A (0/11), but the response rate was increased to 56% (5/9) by the combination of hyperthermia. In the patients with arterio-portal shunt, therapeutic effects were observed in 17% (1/6) and 50% (1/2) of Group A and Group B, respectively. In the patients with portal invasion (Vp2 and Vp3), no favorable response was demonstrated in Group A (0/4), but tumor response was demonstrated in one out of 3 cases in Group B. One- and two-year survival rates were 59% and 53%, respectively, in Group A, and 93% and 45%, respectively, in Group B. The DSM, temporary embolus, is suitable for the combination of hyperthermia because chemo-embolization using DSM can be performed many times. Therefore, these results suggested that chemo-embolization using DSM should be beneficial as combination therapy for unresectable hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1989

[Traumatic diaphragmatic hernia].

Five cases of traumatic diaphragmatic hernia were reported and 495 cases reported in Japan were reviewed. Analysis of cases of hernia following blunt trauma in the present study provided a simple classification of fissure of the diaphragm, i.e., "tension type (indirect type)" and "impact type (direct type)". In the former type, the fissure occurs in the central tendon or its vicinity in the diaphragm as a result of distortion of the bony thorax without direct force on the diaphragm, while in the latter type, the fissure occurs in the diaphragm close to the struck bony thorax as a result of blunt force on the bony thorax to which the diaphragm is attached.

Adult↗
PubMed1989

[Follow-up study on cytophagic histiocytic panniculitis with abnormal immunologic findings].

A 41-year-old patient suffering from multiple subcutaneous nodules of 9 years' duration subsequently left a well-demarcated region of atrophy. Histiocytic panniculitis was observed in biopsy specimens with cytophagocytosis. Histiocytosis was found in the bone marrow. These histiocytes were positive for lysozyme and platelets. He later developed fever and hepatomegaly. Laboratory examination revealed leukocytopenia, mild anemia, and liver disfunction as well as abnormal immunologic findings such as positive LE test and ANA, and an increase of serum IgA and complement levels. The patient was successfully treated with systemic administration of prednisolone and azathiopurine++.

Adult↗
PubMed1988

Effect of colchicine on the transport of precursor enamel protein in secretory ameloblasts studied by 3H-proline radioautography in vitro.

The incorporation of 3H-proline into the secretory ameloblasts of rat molar tooth germs cultured with or without colchicine was studied by light and electron microscope radioautography to determine the function of microtubules in the transport of precursor enamel protein from the rough-surfaced endoplasmic reticulum (rER) to the Golgi cisternae. The grain counts over the transitional vesicles, which accumulated in various cellular regions with colchicine treatment, continued to increase with chase time, unlike in controls. At 30 and 90 min chase, these counts were significantly higher than in controls. Moreover, the total grain count over the organelles (rER, pale granules, and transitional vesicles), which are positioned before the Golgi cisternae in the synthetic pathway, maintained a significantly higher level at 90 min chase in colchicine-treated tooth germs than in controls. The transport of synthesized protein to the Golgi cisternae via transitional vesicles was suppressed in colchicine-treated tooth germs. Some grains appeared with time over pale granular materials that appeared in the intercellular spaces of secretory ameloblasts with colchicine treatment. However, at each chase period, the grain count over pale granular materials was not so high as the count over the enamel in control. The present results indicate that colchicine affects the transport of newly synthesized protein from the rER to the Golgi cisterna via transitional vesicles, probably by interfering with the oriented transport related to microtubular function. It is suggested that the microtubular system may be concerned with the movement of the transitional vesicles.

Ameloblasts↗
PubMed1988

Budding of small vesicles from the rough-surfaced endoplasmic reticulum in secretory ameloblasts of rat molar tooth germs.

The budding of small vesicles from the rough-surfaced endoplasmic reticulum (rER) was examined in the secretory ameloblast of rat molar tooth germs by ordinary fixation or prolonged osmium fixation. The budding of small vesicles from the rER was observed not only at the special region (transitional region) of the rER system, which abutted on the cis-face of the Golgi apparatus, but also at other regions of the rER in the secretory ameloblast. Small vesicles (presumed to be transitional vesicles) were adjacent to the rER, which also showed budding of vesicles. After prolonged osmium treatment, osmium deposits appeared in small vesicles, as well as in the cisternae of the cis saccule of the Golgi apparatus. Small vesicles containing osmium deposits were located at various regions of the cell, including the cis-face of the Golgi apparatus. These findings indicate that the budding of small vesicles from the rER is not restricted to the transitional region of the rER system of the secretory ameloblast, but is found at various regions of the cell. This indicates that newly synthesized proteins may be transferred from the rER cisternae to the transitional vesicles not only in the transitional region of the rER system adjacent to the Golgi apparatus, but also in other regions of the secretory ameloblast.

Ameloblasts↗
PubMed1988

Neurokinin A-like immunoreactivity in feline dental pulp: its distribution, origin and coexistence with substance P-like immunoreactivity.

The distribution and origin of neurokinin A (NKA)-like immunoreactivity were investigated in feline dental pulp by an indirect immunofluorescence method. NKA-containing nerve fibres with varicosities, which entered the dental pulp via apical foramen, were distributed throughout this tissue. Many NKA-containing nerve fibres were localized around blood vessels, but some were observed apart therefrom. At the odontoblastic layer, thin NKA-containing nerve fibres were observed running straight toward the pulp-predentinal border between odontoblasts. After inferior alveolar nerve section, all NKA-containing nerve fibres disappeared in the dental pulp, while the removal of the superior cervical ganglion resulted in no change in the distribution of these fibres. The correlation of NKA-like immunoreactivity and substance P (SP)-like immunoreactivity was also investigated by double-immunofluorescence technique. The distribution of NKA-containing nerve fibres was very similar to that of SP-containing nerve fibres; it appeared that all NKA-containing nerve fibres contained SP.

Animals↗
PubMed1988

Cyclic changes in the properties of maturing enamel in the bovine permanent incisor as revealed by glyoxal bis(2-hydroxyanil) staining.

Staining patterns of the surface and interior of maturing enamel of these tooth germs were examined using the glyoxal bis(2-hydroxyanil) (GBHA) solution which chelates with calcium loosely bound to hydroxyapatite to form insoluble red precipitates. An intense red, band-like pattern of GBHA staining, 1-2 mm wide, first appeared on the incisal portion of lingual enamel surface as complete loops, concentrically arranged; these gradually increased in number. Most of the later-formed bands encircled the entire periphery of the maturing enamel surface. GBHA also revealed reactive areas on the labio-lingual, cut and ground surface of maturing enamel, corresponding exactly to the surface GBHA bands. GBHA did not stain EDTA-etched surface enamel, but did reveal regular staining patterns on the ground surface, disclosed after EDTA treatment. These observations suggest an intimate correlation between the properties of interior and surface enamel, at least with regard to the state of local calcium. The maturation of bovine incisor enamel may start at the lingual aspect of the tooth crown.

Aminophenols↗
PubMed1988

Cytochemical study of the Golgi apparatus and related organelles of the secretory ameloblasts of rat molar tooth germs cultured with and without colchicine.

The Golgi apparatus and Golgi-associated endoplasmic reticulum lysosome (GERL) were examined in the ameloblasts with a cytochemical marker, osmium impregnation, and two enzyme markers, thiamine pyrophosphatase (TPPase) and acid phosphatase (ACPase). In control cultured germs, osmium deposit appeared in one to two immature side cisternae of Golgi stacks; TPPase activity was restricted in a few mature side cisternae and condensing vacuoles. ACPase activity existed in the GERL and, sometimes, in the mature side-cisternae and condensing vacuoles. These findings show that Golgi stacks of ameloblasts consist of several distinct compartments. In colchicine-treated tooth germs, there were morphological and cytochemical changes in both Golgi stacks and GERL. The Golgi apparatus was fragmented and its stacks were scattered throughout the supranuclear region. In some stacks, the number of osmium-positive cisternae was greater than normal; in others they were absent. TPPase and ACPase activity was absent or diminished. These findings suggest the importance of microtubules in the organization of Golgi complex and GERL in the secretory ameloblast.

Acid Phosphatase↗