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Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 397 records · Page 22Linked to original sources
PubMed1988

Neurotransmitters, receptors and neuropeptides in post-mortem brains of chronic schizophrenic patients.

In the analysis of post-mortem brains of 14 chronic schizophrenic patients and 10 controls, biochemical evidence of a hyperdopaminergic state was found in the basal ganglia of schizophrenics; tyrosine hydroxylase activity was increased with a concomitant increase of homovanillic acid. Unusually high tyrosine hydroxylase activity was noted in 2 schizophrenic cases. The Bmax value of 3H-spiperone binding for schizophrenics was higher than the controls. We also found increased specific binding of 3H-kainic acid to the prefrontal cortex in schizophrenics. A negative correlation existed between 3H-kainic acid binding in the medial frontal cortex, and glutamic acid content in various brain areas. Increased immunoreactivity of substance P was found in more than ten brain areas. Methionine-enkephalin was also increased in three areas of the prefrontal cortex of schizophrenics. These results suggest that the hyperdopaminergic state co-existed with glutamatergic hypofunction and increased neuropeptides in various brain areas of chronic schizophrenic patients.

Adult↗
PubMed1988

Occurrence of substance P-like immunoreactive nerve fibers in Krause corpuscles of the dog's tongue.

Substance P-like immunoreactive (SPLI) nerve fibers were demonstrated in the Krause corpuscles of the dog's tongue using the indirect immunofluorescence method and cholinesterase histochemistry. SPLI nerve fibers were often in contact with Krause end bulbs and occasionally entered them. From this result it was suggested that substance P might be involved in sensory mechanism of the Krause apparatus.

Animals↗
PubMed1988

Occurrence of methionine-enkephalin-like immunoreactive cells in the feline vagus nerve.

The occurrence of peptidergic cellular elements in the feline vagus nerve was examined by an immunohistochemical method. Some methionine-enkephalin-like immunoreactive cells were present around a few capillaries within the vagus nerve, whereas substance-P- and vasoactive-intestinal-polypeptide-like immunoreactive cells were not observed. The methionine-enkephalin-like immunoreactive cells had an oval shape and their diameter was 7-10 micron. These cells appeared to be in contact with the pericyte of the capillaries. Though the physiological function of these enkephalin-positive cells is unclear, our findings suggest that they can act as endocrine cells and release methionine-enkephalin into the capillaries.

Animals↗
PubMed1988

A histochemical demonstration of calcium in the maturation stage enamel organ of rat incisors.

The location of calcium in a rapid-frozen and freeze-substituted maturation stage enamel organ of the rat incisors was demonstrated by means of the glyoxal bis(2-hydroxyanil) (GBHA) staining method, which formed insoluble red precipitates of calcium-GBHA complex. In the ameloblast layer, highly GBHA-reactive tubulo-vesicular structures corresponding to mitochondria and some other membrane-bound structures were localized in both ruffle-ended and smooth-ended ameloblasts, although no significant GBHA reaction was localized in the nucleus, Golgi region, nor along the plasma membrane of these cells. In addition, numerous granular GBHA reactions appeared exclusively in association with the ruffled border of ruffle-ended ameloblasts. GBHA reactions were positive, but were considerably weaker in papillary cells than in the ameloblast. These observations provide a first published histochemical mapping of calcium in the maturation stage enamel organ, and suggest the active participation of mitochondria in maturation stage ameloblasts in calcium regulation.

Ameloblasts↗
PubMed1988

[Cholangiocarcinoma associated with Caroli's disease].

We report on an autopsy case of cholangiocarcinoma associated with Caroli's disease. A 38-year-old woman was admitted to our hospital suffering from epigastralgia. A diagnosis of Caroli's disease was made after CT, US, and ERCP testing. Because of diffuse intrahepatic bile duct dilatation, the patient was treated with antibioticus. In August 1985, her CA 19-9 level was 3,800 U/ml. This data suggested the development of a carcinoma secondary to Caroli's disease, but no tumor in the liver had been detected in the US and CT examinations. The patient died on February 1, 1986, of hepatorenal failure, approximately seven years after her first admission. An autopsy revealed diffuse dilatation of the intrahepatic bile duct (Caroli's disease) with a cholangiocarcinoma.

Adenoma, Bile Duct↗
PubMed1988

[A case report of primary liver cancer with cerebral metastasis after hepatic resection].

A 67-year-old male, who had a left hepatectomy for hepatocellular carcinoma, was readmitted to our hospital because of a left hemiparesis. A brain computed tomography scan and an r-carotid angiogram revealed a large mass involving the right parietal area, and thus a brain tumor removal was performed. A histological diagnosis of the removed brain tumor found it to be a metastatic, hepatocellular carcinoma. The patient died of pulmonary congestion due to lung metastasis, approximately 2 years and seven months after hepatectomy, and 1 year and three months after the removal of this metastatic brain tumor. In selected cases, the removal of a metastatic brain tumor seems to bring about improvements in the quality and duration of life.

Aged↗
PubMed1988

[A glomus tumor of the stomach associated with a lipoma].

A case of Glomus tumor of the stomach associated with a lipoma in a 65-year-old female is reported. The patient complained of epigastralgia for three months prior to her admission. X-rays, as well as gastroscopic examinations, revealed two submucosal tumors, one located along the greater curvature of the gastric antrum and the other on the posterior wall of the upper corpus. A preoperative angiographic study showed hypervascularity and tumor staining. Histologically, one tumor was diagnosed as being Glomus tumor and the other, a lipoma. Thus this rare case of two submucosal tumors in the stomach is discussed and 39 previous gastric Glomus tumor cases found in the domestic literature are reviewed.

Aged↗
PubMed1987

Lipid peroxidation is not the cause of lysis of human erythrocytes exposed to inorganic or methylmercury.

Exposure of human erythrocytes in a 50% hematocrit to 0.5-1 mM Hg2+ initiated immediate hemolysis which proceeded at a constant rate without any formation of lipid hydroperoxides. Treatment of 0.03% hematocrits with 0.4 ppm of Hg2+ or 40 ppm of methylmercury caused rapid hemolysis after a short lag period. The kinetics of the process were unaltered by saturation of the cell suspensions with oxygen, by its replacement with He or CO, or by variation in the level of vitamin E in the membranes. The results show that peroxidation of erythrocyte membrane lipids is not the cause of hemolysis induced by either Hg2+ or methylmercury.

Erythrocytes↗
PubMed1987

The distribution and origin of calcitonin gene-related peptide-containing nerve fibres in feline dental pulp. Relationship with substance P-containing nerve fibres.

The origin and distribution of calcitonin gene-related peptide (CGRP)-like immunoreactivity in feline dental pulp were studied using indirect immunofluorescence. Nerve fibres with varicosities exhibiting CGRP-like immunoreactivity were observed to enter the pulp with blood vessels. Many CGRP-containing nerve fibres were found to extend along blood vessels in the central pulp, and some of these fibres exhibited a network arrangement in the walls of dental pulp blood vessels. However, some of fibres were apparently not associated with blood vessels. Some thin, CGRP-containing nerve fibres formed a part of the nerve plexus in the subodontoblastic area and penetrated into the odontoblastic layer. In animals that had undergone transection of the inferior alveolar nerve, no CGRP-containing nerve fibres were observed. Application of a double-immunofluorescence staining technique also revealed that the distribution of CGRP-containing nerve fibres is very similar to that of substance P-containing nerve fibres.

Animals↗
PubMed1987

Immunohistochemical observation on the correlation between substance P- and vasoactive intestinal polypeptide-like immunoreactivities in the feline dental pulp.

The correlation between substance P (SP) and vasoactive intestinal polypeptide (VIP)-containing nerve fibres in the pulp was examined by double immunofluorescence. Both SP- and VIP-containing fibres entered the pulp in bundles with the blood vessels and spread throughout the pulp. In the coronal pulp, both SP- and VIP-containing nerve fibres formed networks on the walls of blood vessels, but both peptide-containing nerve fibres were not observed together in relation to vessels. There were more SP-containing fibres than VIP-containing ones. In the odontoblast layer, there were many SP-containing fibres but few VIP-containing ones.

Animals↗
PubMed1987

Immunohistochemical study on regeneration of substance P-like immunoreactivity in rat molar pulp and periodontal ligament following resection of the inferior alveolar nerve.

Using an indirect immunofluorescence method, after 14 days, regenerated SP-containing nerve fibres first appeared around the blood vessels in apical and coronal regions of the pulp and apical and middle regions of the periodontal ligament. Penetration of regenerated SP-positive fibres into the dentine and predentine was observed 25 days after operation. The number of regenerated SP-containing fibres recovered to nearly to the same level as in intact controls by 35 days. They had a similar distribution in the tissues.

Animals↗
PubMed1987

Specific binding of transposase to terminal inverted repeats of transposable element Tn3.

Tn3 transposase, which is required for transposition of Tn3, has been purified by a low-ionic-strength-precipitation method. Using a nitrocellulose filter binding assay, we have shown that transposase binds to any restriction fragment. However, binding of the transposase to specific fragments containing the terminal inverted repeat sequences of Tn3 can be demonstrated by treatment of transposase-DNA complexes with heparin, which effectively removes the transposase bound to the other nonspecific fragments at pH 5-6. DNase I "footprinting" analysis showed that the transposase protects an inner 25-base-pair region of the 38-base-pair terminal inverted repeat sequence of Tn3. This protection is not dependent on pH. Interestingly, binding of the transposase to the inverted repeat sequences facilitates DNase I to nick at the end of the Tn3 sequence. It was also observed that the transposase protects the end regions of restriction fragments with a cohesive sequence at their 5' end or with a flush end from DNase I cleavage. The specific and nonspecific binding of transposase to DNA is ATP-independent.

Adenosine Triphosphate↗
PubMed1987

The influence of vanadate on calcium uptake in maturing enamel of the rat incisor.

The influence of vanadate, a potent inhibitor of Ca2+-ATPase and Na+-K+-ATPase, on 45Ca uptake in maturing enamel of the rat incisor was investigated by a vascular perfusion method combined with 45Ca autoradiography. The morphological integrity of the maturation-stage enamel organ was well-retained during vascular perfusion under all the experimental conditions. Distinct patterns of 45Ca labeling, comparable with those found in previous in vivo 45Ca autoradiographic studies, appeared in the maturing enamel after vascular perfusion with a standard perfusate. One mmol/L vanadate added to the standard perfusate caused a drastic decrease in 45Ca uptake in the maturing enamel, corresponding to the ruffle-ended ameloblasts, leaving narrow peaks of moderate intensity corresponding to the bands of the overlying smooth-ended ameloblasts. The in vitro labeling of exposed enamel surfaces with 45Ca revealed blackening of autoradiographic emulsion in wide bands separated by unlabeled or slightly labeled narrow ones resembling the distribution of smooth-ended ameloblasts in both control and vanadate-treated incisors. Our observations indicate that the ruffle-ended ameloblasts of the rat incisor serve as an efficient diffusion barrier to calcium ions and regulate transcellular calcium transport to the maturing enamel, at least in part, by a vanadate-sensitive mechanism.

Ameloblasts↗