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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 937 records · Page 52Linked to original sources
PubMed1985

Possible differential diagnosis of neuroblastoma from rhabdomyosarcoma and Ewing's sarcoma by using a panel of monoclonal antibodies.

The accurate diagnosis of malignant tumor type is essential to enable the correct therapeutic regimen to be followed and to predict a patient's prognosis. However, the differential diagnosis of "small-round-cell" tumors, represented by neuroblastoma, rhabdomyosarcoma, lymphoma/leukemia and Ewing's sarcoma, can occasionally be difficult by conventional morphological and biochemical methods. If tumor membrane markers were available, these could provide rapid and accurate diagnostic aids. In the present work, a panel of 9 monoclonal antibodies raised against hematopoietic cells (BA-1, BA-2, J-5 and B7/21), brain cells (UJ-13A, UJ-127-11 and anti-Thy-1), and neuroblastoma cells (HSAN1.2 and PI153/3) was used to analyze the membrane phenotypes of 12 neuroblastoma, 4 rhabdomyosarcoma and 3 Ewing's sarcoma cell lines and cells of 3 fresh bone marrow tumors. BA-1, UJ-127-11 and PI153/3 antibodies may be useful for the differential diagnosis of neuroblastoma from rhabdomyosarcoma and Ewing's sarcoma.

Antibodies, Monoclonal↗
PubMed1984

[The determination of the recognition site of an antiserum detecting desialylation on O-glycosidic carbohydrates of hCG and its clinical applications. The relationship between the presence of asialo-hCG and malignant change in trophoblastic disease].

Human chorionic gonadotropin (hCG) is a specific tumor marker glycoprotein hormone for trophoblastic diseases. It contains 4 asparagine-linked and 4 serine-linked carbohydrate units. Recently, variations in the carbohydrate moieties of hCG in chorio-carcinoma have been suggested. However, the immunological method of detecting these malignant transformational changes of carbohydrate units in hCG have not been investigated. We therefore attempted to assess the possibility of establishing a radioimmunoassay system which can detect these transformational changes in serine-O-glycosidically linked carbohydrate units of hCG. HCG-specific hCG beta COOH-terminal portion contains all 4 O-glycosidically linked sugar chains (positions 121, 127, 132 and 138). An antiserum (R141) generated against the enzymatically cleaved, desialylated hCG beta COOH-terminal peptide (residue 123-145) by toepad immunization method was extensively characterized. This antiserum reacts with asialo-hCG better than with native hCG. It does not bind with synthetic COOH-terminal peptides nor monosaccharides such as N-acetyl-D-galactosamine and D-galactose, which are sugar components in O-glycosidic carbohydrate chains. The HF-treated asialo-hCG, in which galactose residues are further removed, still reacts with the antiserum. The antiserum requires both the peptide sequence and N-acetyl-D-galactosamine residues for its binding. Glycophorine and fetuin, which also contain the same O-glycosidic carbohydrate structure, do not react with the antiserum. Beta subunit gains its binding capability to the antiserum only upon desialylation, while native alpha and beta subunits do not react. The antiserum has high specificity toward asialo-hCG in which particularly O-glycosidic carbohydrate units are desialylated. With a specific radioimmunoassay system using this antiserum (R141), urinary hCG preparations from 29 patients with various trophoblastic diseases were analyzed. Asialo-hCG immunoactivity was insignificant in all patients with hydatidiform mole, invasive hydatidiform mole and persisted trophoblastic disease. However, asialo-hCG was found in 2 out of 6 cases of choriocarcinoma. The existence of asialo-hCG may be related to the advancement of disease.(ABSTRACT TRUNCATED AT 400 WORDS)

Asialoglycoproteins↗
PubMed1984

Identification of motoneurons innervating the tensor tympani muscle in the rabbit: a retrograde horseradish peroxidase study.

After injecting horseradish peroxidase into the tensor tympani muscle in the rabbit, neuronal cell bodies labeled retrogradely with the enzyme were seen in the ventrolateral regions of the pontine tegmentum. These tensor tympani motoneurons were located in the 'nucleus n' as well as in the rostrodorsal part of the medial 'cell group k' of Meessen and Olszewski [4].

Animals↗
PubMed1984

[The preparation of an hCG-specific immunoadsorbent using hCG beta-carboxyl-terminal peptide antibody and its application to isolate HCG-like substances from human pituitary glands].

It has been difficult to distinguish hCG from hLH because the two are structurally similar. However, hCG beta subunit has a unique carboxyl terminal peptide, which is not present in hLH and other gonadotropins. Taking advantage of this unique structural feature of hCG beta subunit, hCG-specific antisera have been produced. In order to isolate hCG-like substances from human pituitary glands, the specific immunoadsorbent for hCG was prepared using the isolated monospecific antibody from these antisera. Specific IgG fraction was isolated from an antiserum by affinity chromatography using synthetic carboxyl-terminal peptides as ligands. The purified IgG was conjugated to Sepharose 4B to prepare a specific immunoadsorbent. Immunoadsorbent thus prepared was fully specific to hCG without any crossreactivity with hLH. Attempts to isolate hCG-like substances from two different human pituitary extracts were made by affinity chromatography using this hCG-specific immunoadsorbent. Elution conditions for hCG-like substances from the immunoadsorbent were studied. We found that 1 M NH4OH was a highly effective eluent in this affinity chromatographic system. An advantage of 1M NH4OH is its volatile nature, which permits further steps of purification to be performed directly or after lyophilization without extensive dialysis. The immunoaffinity procedures described in this paper may provide a convenient approach to purify hCG-like substances from both endocrine glands and biological fluids.

Antibodies↗
PubMed1984

Light and electron microscopic demonstration of hypothalamic projections to the parabrachial nuclei in the cat.

Hypothalamic connections with the parabrachial nuclei in the cat were studied at light and electron microscopic levels following wheat germ agglutinin-horseradish peroxidase injections into the parabrachial nuclei and electrolytic lesions in the hypothalamus. The greatest concentration of retrogradely labeled neurons occurred in the paraventricular nucleus. Labeled neurons were also seen within the preoptic, anterior, lateral, dorsomedial and ventromedial hypothalamic nuclei. Hypothalamic lesions resulted in the degeneration of terminals forming axosomatic and axodendritic synapses in the parabrachial nuclei, particularly its lateral division. These findings support the idea that hypothalamic connections to specific regions of the parabrachial nuclei may underlie the topographical functional organization demonstrated for these brainstem nuclei.

Amygdala↗
PubMed1984

Immunohistochemical demonstration of serotonin-containing nerve fibers in the hypothalamus of the monkey, Macaca fuscata.

The distributional pattern of serotonin-containing nerve fibers in the hypothalamus of the monkey (Macaca fuscata) was analyzed with the use of the peroxidase-antiperoxidase method in conjunction with a highly sensitive and specific anti-serotonin serum. The highest concentrations of serotonin-immunoreactive varicose fibers were found in the nucleus praeopticus medialis, nucleus ventromedialis hypothalami, and the complex of mammillary nuclei (nucleus praemamillaris, supramamillaris, mamillaris medialis et lateralis). However, the nucleus suprachiasmaticus, where numerous serotoninergic fibers have been reported to occur in the rat, appeared to be almost devoid of these fibers. The infundibular stalk and the intermediate and posterior lobes of the pituitary contained considerable numbers of immunoreactive fibers. The present study provides a morphological basis for possible clarification of the influence of serotoninergic projections on various neuroendocrine mechanisms in primates. Furthermore, an attempt was made to clarify the differences and similarities concerning the distributional patterns of serotoninergic nerve fibers within the monkey hypothalamus in contrast to the rat hypothalamus.

Animals↗
PubMed1984

Immunohistochemical study on the morphology of enterochromaffin cells in the human fundic mucosa.

The morphology of enterochromaffin (EC) cells in the human fundic mucosa was investigated at the light-microscopic level by means of the unlabeled peroxidase anti-peroxidase method, with the use of a highly specific anti-serotonin serum. EC-cells in the human fundic mucosa were sparsely distributed below the neck portion of the gland, but were found to be rather numerous in its lower half. Immunohistochemistry revealed marked pleomorphic and seemingly polynuclear EC-cells or cells with long, sometimes multipolar cytoplasmic processes. In addition, luminal contacts and contiguity between EC-cells, or interglandular connections were also encountered. The present immunohistochemical procedure permits, for the first time, a clear-cut morphological visualization of the entire population of EC-cells, and reveals the distinctive morphological features of these cells in the human fundic mucosa. These morphological findings imply that EC-cells in the fundic mucosa may be crucial in gastric function.

Chromaffin System↗
PubMed1984

Serotonin nerve fibers in the primary visual cortex of the monkey. Quantitative and immunoelectronmicroscopical analysis.

A quantitative and immunoelectronmicroscopical analysis of serotonin nerve fibers in the primary visual cortex of the monkey (Macaca fuscata) was made using a sensitive immunoperoxidase method for serotonin. The overall numerical density of serotonin-containing varicosities in the primate striate cortex was approximately 770,000/mm3 and the highest concentration of immunoreactive varicosities (ca. 1,400,000/mm3) was observed in the upper portion of layer IVc, the next highest concentration being in layer IVb (ca. 1,180,000/mm3). At the ultrastructural level, the electron dense immunoreactive products were observed in the small granules (10-65 nm in diameter). The varicosities were usually small (0.5-1.0 micron in diameter) and made contact with both stellate and pyramidal cells. Serotonin fibers were often in close apposition to the poorly myelinated axons in layers IVb, V, and VI, and they rarely formed distinct synaptic structures with unlabelled neuronal elements.

Animals↗
PubMed1984

Changes of n-hexane neurotoxicity and its urinary metabolites by long-term co-exposure with MEK or toluene.

It is well known that the neurotoxicity of n-hexane may be modified upon co-exposure with other organic solvents. In order to elucidate this mechanism further, rats were exposed to 500ppm n-hexane, 500ppm n-hexane plus 500ppm methyl ethyl ketone (MEK), 500ppm n-hexane plus 500ppm toluene, or air only for 8h per day for 33 weeks. The body weight, motor nerve conduction velocity (MCV) and distal latency (DL) were determined before exposure and after 4, 8, 12, 16, 20, 24, 29, and 33 weeks of exposure. From each group one rat was histologically examined after 33 weeks of exposure. To establish a relationship between the n-hexane neurotoxicity and changes in biotransformation, urinary metabolites (2-hexanol, methyl n-butyl ketone (MBK), 2,5-hexanedione, 2,5-dimethylfuran, and gamma-valerolactone) were measured by gas chromatography on the first exposure day, and after 1, 2, 4, 8, 12, 16, 20, 24, 29, and 33 weeks of exposure. The total amounts of metabolites of n-hexane in the urine significantly decreased upon co-exposure of n-hexane, with MEK as well as with toluene, in comparison with those of animals exposed to n-hexane alone. 2,5-Hexanedione, which is considered the ultimate neurotoxic metabolite of n-hexane, also decreased. Electrophysiological and histological studies did not reveal statistically significant differences between any two groups among the four groups. It is considered that the present results might explain the combined effects of n-hexane and toluene which decrease n-hexane neurotoxicity, but do not explain those of n-hexane and MEK. Therefore, other mechanisms of the combined effects of n-hexane and MEK should be studied.

Animals↗