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Biomedical subjects

T Kaku

Publications and source records attributed to T Kaku.

At least 163 records · Page 9Linked to original sources
PubMed1985

Intestinal metaplasia as a common option of oval cells in relation to cholangiofibrosis in liver of rats exposed to 2-acetylaminofluorene.

Oval cell proliferation in the liver was studied in rats exposed to dietary 2-acetylaminofluorene for 2 weeks with partial hepatectomy performed midway at 1 week. Using autoradiography after either continuous or pulse exposure to [3H]thymidine, histochemical staining for leucine aminopeptidase and gamma-glutamyltransferase, and transmission electron microscopy, we found that every animal showed islands of oval cells with small intestinal metaplasia at 3 weeks. Transitions from these islands of metaplasia to cholangiofibrosis were commonly seen. The importance of small intestinal metaplasia of oval cells in the genesis of cholangiofibrosis is presented and discussed.

2-Acetylaminofluorene↗
PubMed1985

[Two cases of paragangliomas of the cauda equina--case reports and review of the literature].

Paragangliomas are tumors arising in the paraganglia and rarely occurring in the cauda equina. We report two cases of paraganglioma arising in this region. The tumors exhibited a typical "Zellballen" pattern, and immunohistochemical studies were positive for neuron-specific enolase, but negative for S-100 protein and glial fibrillary acidic protein. Electron microscopic studies confirmed electron-dense neurosecretory types of granules in the tumor cells. Only 23 cases of paragangliomas in this region have been previously reported. A brief review of the literature is included.

Cauda Equina↗
PubMed1984

The relationship of colonic carcinogenesis and hepatic vascular tumors induced by subcutaneously injected-1,2-dimethylhydrazine dihydrochloride in specific pathogen free mice.

1,2-Dimethylhydrazine dihydrochloride (DMH) is one of the most reliable carcinogens for experimental colonic carcinogenesis. In order to evaluate the biological significances of target organ specificity of DMH-induced carcinogenesis, specific pathogen free (SPF) BALB/c mice were injected subcutaneously with DMH for 30 weeks, and were studied pathologically for tumor development of various organs. The data showed that colon tumor developed only at 2% of these mice. However, it produced 100% incidence of malignant endotheliomas and angiosarcomas of blood vessels and these tumors selectively appeared in the liver. There were no overt foci of primary vascular tumors in the heart, lung, kidney, muscle as well as spleen. This tumor model may reveal that the organ specificity of the carcinogenic activity with DMH could be converted, possibly depending upon the bacterial flora in the intestines, and very suitable for the investigation of implications of intestinal bacteria on the colonic and vascular tumorigenesis.

1,2-Dimethylhydrazine↗
PubMed1984

Functional differentiation of hypoglossal motoneurons during the amygdaloid or cortically induced rhythmical jaw and tongue movements in the rat.

Activity of hypoglossal motoneurons was studied in relation to the amygdaloid or cortically induced rhythmical jaw and tongue movements in the rat. Tongue protrudor and retrusor motoneurons were antidromically identified by stimulation of the medial and the lateral hypoglossal nerve branches, respectively. About 80% of protrudor motoneurons excited during the opening phase of the rhythmical jaw movements with or without prior excitation. Most of them did not respond to amygdaloid or cortical stimulation. Fifty-three percent of retrusor motoneurons were excited during the closing phase and 31% discharged around the peak opening. The majority of them and a few protrudor motoneurons responded to amygdaloid or cortical stimulation with similar latencies. Activities of the medial and the lateral hypoglossal branches corresponded with the discharge patterns of respective motoneurons. Tongue protrusion and retrusion appeared to slightly precede jaw opening and closing, respectively during the rhythmical jaw and tongue movements. This was probably due to activity of the brain stem pattern generator.

Amygdala↗
PubMed1984

Merkel cell tumor of the skin. Ultrastructural and immunohistochemical studies.

A skin tumor of a 66-year-old female was investigated morphologically and immunohistochemically. The tumor was located within the dermis and comprised of rounded cells with scanty cytoplasm, which proliferated forming a small nest or trabecular arrangement. Electron microscopic observation indicated the presence of dense-core granules within the tumor cell cytoplasm suggesting that the tumor was derived from Merkel cells. Occasionally clusters or bundles of the intermediate filaments were found in the perinuclear cytoplasm of the tumor cells. Each tumor cell was connected with desmosomes. Immunohistochemical staining with anti-keratin antiserum showed positive reaction at the perinuclear cytoplasm of the tumor cells indicating that the cluster of the microfilaments presumably contains keratin. Conversely S-100 protein was negative in the tumor cells. The results obtained strongly suggest that the tumor or Merkel cell was considered to be derived from the epidermal immature cells rather than from the neural crest.

Aged↗
PubMed1984

Studies on the proliferation and fate of oval cells in the liver of rats treated with 2-acetylaminofluorene and partial hepatectomy.

The kinetics of oval cell proliferation in the liver and their fate were studied by combined autoradiography and immunohistochemical staining for epidermal prekeratin and epoxide hydrolase (EH). The oval cell proliferation was induced in rats by exposure to dietary 2-acetylaminofluorene (2-AAF) for 2 weeks with the midway performance of partial hepatectomy (PH). The labeling with 3H-thymidine [3H-TdR] was done in different groups of rats by two procedures: continuous exposure for 1 week with the aid of a minipump and brief exposure by the administration of a single dose. The livers of groups of animals were examined from 1 to 10 weeks after PH. Oval cells and duct epithelium showed positive staining for prekeratin and negative for EH, whereas hepatocytes showed the reverse pattern of staining. A critical finding was the observation that the exposure to the 2-AAF inhibited virtually completely the labeling of hepatocytes with [3H]-TdR in the caudate lobe and incompletely in the right lobe without interfering with the labeling of the oval cells in either lobe. This made it possible to study the fate of the oval cells vis-à-vis hepatocytes. This qualitative-quantitative study of oval cells and hepatocytes clearly indicates that oval cells under these experimental conditions do not become hepatocytes within 10 weeks. Over 80% of oval cells disappear within this period, and the remainder persist as such. These results indicate that under one set of experimental conditions related to hepatocarcino-genesis in the rat, no evidence for the conversion of oval cells to hepatocytes was obtained.

2-Acetylaminofluorene↗
PubMed1983

Comparison of formalin- and acetone-fixation for immunohistochemical detection of carcinoembryonic antigen (CEA) and keratin.

The purpose of the present study was to compare the relative merits of cold acetone and buffered formalin as fixatives for the detection of carcinoembryonic antigen and keratin in permanently embedded tissues using a peroxidase-antiperoxidase (PAP) immunohistochemical procedure. The effect of treatment with the proteolytic enzyme pronase also was examined in the formalin-fixed tissues. Cold acetone was found to be superior to formalin for the preservation of CEA and keratin antigenic activities in a variety of benign and malignant tissues. Pronase treatment markedly increased the staining intensities of both antigens in formalin-fixed tissues. For many tissues, however, superior results were obtained using the cold acetone method, and this technic is recommended for the optimum retention of antigenic activity in permanently embedded tissues.

Acetone↗
PubMed1983

Extremely well-differentiated adenocarcinoma ("adenoma malignum") of the cervix.

Eight cases of extremely well-differentiated adenocarcinoma of the cervix were collected for clinicohistopathologic study. The tumors, despite having an innocuous histologic appearance, were characterized by irregular shapes and various sizes of the glands, with intraluminal papillary projections supported by thin connective tissue cores. They showed, in addition, sharp outpouching and distension of the malignant glands by mucin, as well as leakage into stroma. Clinically, such tumors were highly malignant and the prognosis was poor. Six patients died within 3 years following surgical treatment. In six of the eight cases, Feulgen microspectrophotometric DNA measurements disclosed patterns similar to those of normal endocervical glands, except for 4c to 6c aneuploid cells.

Adenocarcinoma↗
PubMed1983

Glial fibrillary acidic protein in tuberous sclerosis.

We examined two cases of tuberous sclerosis for the presence of glial fibrillary acidic protein (GFAP) using the immunoperoxidase technique. The majority of abnormal giant cells in the cerebral cortex showed no reaction to anti-GFAP. Some abnormal cells in the cortical tuber and white matter showed a weak positive reaction. All of the subependymal tumor cells showed no GFAP in their cytoplasm. The abnormal giant cells in tuberous sclerosis, morphologically similar to gemistocytic astrocyte, are not accompanied by antigenic properties of GFAP.

Adolescent↗
PubMed1983

[Merkel cell tumor of the skin].

A skin tumor of a 66-year-old female was examined morphologically and immunohistochemically in relation to its histogenetic aspect. The tumor was located within the dermis and composed of compact round cells with scanty cytoplasm. Electron-microscopic study revealed the presence of dense-cored granules within the cytoplasm. Thus the tumor was thought to derive from Merkel cells. The tumor cells were positive for keratin and negative for S-100 protein by immunohistochemistry. Therefore, we posit that the tumor cells did probably not originate from the neural crest, but rather from epidermal immature cells.

Adenocarcinoma↗
PubMed1982

Isolation and some properties of the hemolysins from the crude venom extract of scorpion telson, Heterometrus gravimanus.

THe hemolytic and enzymic investigations of the crude venom from Heterometrus gravimanus scorpion have revealed the presence of both direct and indirect (phospholipase A) hemolysins. The direct hemolysins were isolated from the lyophilized crude venom extract by Sephadex G-100 gel filtration, SP-Sephadex C-25 column chromatography, gel filtration of Sepharose 4B and Sephacryl S-300. The two direct hemolysins having high molecular weights, P (A) (M.W.: nearly 200 X 10(4)) and P (B) (M.W.: 22 X 10(4)), were obtained with the activity recoveries of 8% and 39.4%, respectively. P (B) was further separated into three fractions by Sephadex G-200 gel filtration, namely F (A) (M.W.: 17 X 10(4), F (B) (M.W.: 4.5 X 10(4) and F (C) (M.W.: below 1 x 10(4), with the significant losses of direct hemolytic activities. However, F (B) had phospholipase A activity and this activity was partially inhibited by p-bromophenacyl bromide. F (B) and F (C) were soluble, even after the treatment of dialysis and lyophilization, in the isotonic saline and distilled water, and were homogeneous in polyacrylamide gels after going through disc and vertical plate electrophoreses. Furthermore, the schlieren pattern of F (B) also showed homogeneity of the preparation. The protein parts of hemolysins were found to be acidic ones. Although ultraviolet spectra of them were somewhat varied in accordance with their protein contents in the samples, the spectra of exitation and emission were almost identical. The direct hemolysins are presumably glycoproteins, since they are positive in the sugar reactions, and the difference between P (A) and P (B) is supposed to consist in the sugar part rather than that of proteins.

Amino Acids↗