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Biomedical subjects

Y Tajima

Publications and source records attributed to Y Tajima.

At least 163 records · Page 9Linked to original sources
PubMed1991

Segmental primary sclerosing cholangitis mimicking bile duct cancer--report of a case and review of the Japanese literature.

A rare case of the segmental type of primary sclerosing cholangitis (PSC) is reported herein. A 27 year old Japanese man with obstructive jaundice was referred to our hospital with a provisional diagnosis of bile duct cancer at the hepatic hilum. A PTCD tube had been inserted from the right anterior segmental duct and direct cholangiograms showed complete obstruction of the bile duct at the confluence of the right and left hepatic ducts. Resection of the extrahepatic bile duct and partial hepatectomy were thus performed, however, the postoperative histological examination revealed no malignant features. Instead, the lesion was shown to be compatible with PSC microscopically. A diagnosis of PSC was finally established on the basis of clinical features, cholangiographic appearance and the pathological report.

Adult↗
PubMed1991

Light and electron microscopic demonstration of wheat germ agglutinin binding in the pericellular matrix of rat mandibular condylar cartilage.

Binding of wheat germ agglutinin to rat mandibular condylar cartilage was investigated with the avidin-biotin peroxidase complex. Binding sites were observed in the pericellular matrix of the hypertrophic cell zone. Two distinct patterns were identified: one showed binding to the pericellular matrix without apparent contour; in the other binding was confined to the matrix but with conspicuous condensation forming a pericellular rim. The first binding pattern was seen particularly in the upper part of the hypertrophic cell zone adjoining the mature cell zone; the second was localized in the lower part of this zone adjacent to the site of endochondral calcification. The binding sites in the pericellular matrix are assumed to be NANA and/or GlcNAc in view of the sugar specificity of this lectin. The presence of these binding sites in this region may be due to a structural alteration or modification of proteoglycans in the course of preparation for endochondral calcification.

Animals↗
PubMed1991

Immunocytochemical detection of S-100 protein in rat mandibular condylar cartilage.

Light and electron microscopic immunocytochemistry was used to localize S-100 protein. It was demonstrated in chondrocytes of the proliferative and hypertrophic zones but none could be found in the fibrous articular layer. The staining intensity for S-100 protein was stronger in the hypertrophic cells than in chondrocytes from the proliferative zone. Ultrastructurally, immunoreactive gold particles were detected in the cytosolic region, closely apposed to the profiles of endoplasmic reticulum with occasional dense aggregations. A few gold particles were seen on the nuclear chromatin and on condensing vacuoles of Golgi complexes. Because of the calcium-binding and possibly fatty acid-binding properties of the protein molecule, the immunocytochemical expression of S-100 protein in the chondrocytes may be involved in cartilage cell differentiation, metabolism and mineralization.

Animals↗
PubMed1991

X-ray studies of thin filaments in a tonically contracting molluscan smooth muscle.

In the X-ray pattern of the ABRM, layer lines from the thin filaments can be clearly observed not only at the small angles but also at the medium angles up to 0.145 A-1, and the layer lines are changed in intensity in the tonically contracting state in both the small and medium angle regions. Because tropomyosin does not contribute significantly to the layer lines except the three near the equator, it is suggested that structural change of actin occurs in the tonically contracting state. The intensity profiles of the layer lines with the 0th Bessel order corresponding to the axial periods 27.9, 13.8, 9.3, and 6.9 A indicate axial staggering of the inner and outer domains of actin by about 1/3 of the axial period of actin, and the presence of a small mass on the shoulder of the outer domain at a distance of 50 A from the filament axis. The difference Patterson functions calculated from the intensities of the four layer lines with the 0th Bessel order suggest that peptide chains are oriented perpendicularly to the filament axis in the actin molecules. The peptide chain direction is presumably tilted against the filament axis in the outer part of actin as a result of structural change by tonic contraction.

Acetylcholine↗
PubMed1991

White-spotting mutations affect the regenerative differentiation of testicular germ cells: demonstration by experimental cryptorchidism and its surgical reversal.

The effect of white-spotting (W) mutations on differentiation of testicular germ cells was investigated by using experimental cryptorchidism and its surgical reversal. All mutant mice used in this study (Wv/+, Wsh/+, Wf/+ and Wf/Wf) showed normal fertility and well-ordered spermatogenesis, as in congenic +/+ mice. In the cryptorchid testis, which contains only type A spermatogonia as germ cells, the number and the proliferative activity of type A spermatogonia in mutant mice were comparable to +/+ mice. On the other hand, surgical reversal of the cryptorchid testis in mutants resulted in impaired regenerative differentiation of germ cells. Although complete recovery of spermatogenesis was observed in +/+ mice, testicular weight in Wsh/+, Wf/+ and Wf/Wf mice recovered to approximately 60-70% of intact levels, and some portions of seminiferous epithelium showed incomplete spermatogenesis. In Wv/+ mice, however, ability to recover the weight was completely lost, and only type A spermatogonia existed as germ cells in seminiferous tubules 3 mo after surgical reversal. These results suggest that W mutation affects the differentiation through type A spermatogonia to type B spermatogonia, indicating the functional significance of W (c-kit) in early spermatogenesis.

Animals↗
PubMed1991

Morphometric studies for objective diagnosis of intraductal carcinoma of the breast.

In order to obtain objective histologic criteria for distinguishing intraductal carcinomas of the breast from benign intraductal hyperplasia, a morphometric study was carried out on 15 cases of breast carcinoma (5 cases of comedo carcinoma, 5 cribriform carcinoma and 5 papillotubular carcinoma) and 10 benign control lesions (5 papilloma and 5 fibrocystic disease). Morphometric analysis was performed for each group with regard to 1) mean nuclear area, 2) mean nucleolar size, 3) mitotic index, and 4) nuclear count within predefined area (nuclear density) in histologic specimens. The results obtained were as follows: 1) Mean nuclear area for comedo carcinoma was distinctively large. This, together with its coefficiency variance, may be a good indicator for identifying this type of carcinoma. 2) Mean nucleolar size was significantly larger in each carcinoma group than in their benign counterparts. Nucleolar size was therefore considered to be the most reliable parameter for discriminating malignant cells from benign hyperplasia. 3) Mitotic index was relatively high in comedo and papillotubular carcinomas. 4) No difference was seen in nuclear density between the malignant and benign groups. In addition to the major criteria, combined application of these morphometric indicators might also be helpful for practical histologic assessment.

Breast↗
PubMed1991

Biologically active kit ligand growth factor is produced by mouse Sertoli cells and is defective in SId mutant mice.

In order to define the role of Kit ligand (KL) growth factor encoded at the mouse steel (SI) locus in spermatogenesis, we have examined its production in Sertoli cells. As a measure KL growth factor bioactivity, the ability to support proliferation and maintenance of mast cells was used in co-culture with primary mouse Sertoli cells. On the sertoli cells derived from +/+ and Wv/Wv mice, +/+ mast cells proliferated and were supported for more than 2 weeks, but not W/Wv mast cells. In contrast, Sertoli cells from SId/SId mice could not support +/+ mast cell proliferation under similar conditions. The supportive effect required close-range interaction of Sertoli cells with cultured mast cells. These results indicate that Sertoli cells derived from +/+ and Wv/Wv but not SId/SId mutant mice produce biologically active KL growth factor as a membrane-bound form. The biologically active KL of Sertoli cells may also play an important role in germ cell growth and differentiation.

Animals↗
PubMed1991

Triazole antifungals. IV. Synthesis and antifungal activities of 3-acylamino-2-aryl-2-butanol derivatives.

New triazole compounds were designed and synthesized as potential inhibitors of the fungal cytochrome P-450 14 alpha-demethylase. In testing for antifungal activity against a mouse systemic Candida albicans infection, (2R,3R)-3-acylamino-2-aryl-2-butanol derivatives III exhibited remarkably high efficacy after oral or parenteral administration. The structure-activity relationships of these amidoalcohols were evaluated.

Antifungal Agents↗
PubMed1991

Diurnal changes in plasma melatonin and the timing of reproductive onset in anestrous sheep fed melatonin.

Seasonally anestrous Suffolk ewes (n = 28) were randomly divided into 5 groups and treated with varying doses of melatonin as follows; Groups C (n = 4), M1 (n = 6), M2 (n = 6), M3 (n = 6), M4 (n = 6) of ewes were fed pellets containing 0, 1, 2, 3 and 4 mg melatonin, respectively, daily for 60 days from May 17 (Day 0). Following feeding of the pellets at 13.00 hr plasma levels of melatonin rapidly increased reaching the peak values within 30 min, which ranged from 92.0 to 292.7 pg/ml and were highly correlated with the dose of melatonin administered (r = 0.986, P less than 0.01). Maximum dose of melatonin (4 mg) produced an increase of plasma melatonin similar in magnitude to nocturnal peaks of endogenous secretion. The onset of ovulatory cyclicity, assessed from plasma progesterone profiles, was advanced by melatonin administration. The mean +/- SEM intervals from the commencement of melatonin treatment until the onset of ovulatory cyclicity were 53.0 +/- 5.8, 53.6 +/- 2.5, 42.0 +/- 5.6 and 44.3 +/- 4.3 days for the Groups M1, M2, M3 and M4, respectively, which were shorter (M1, P less than 0.05; M2, M3 & M4, P less than 0.01) than that for the Group C (72.5 +/- 1.4 days). The melatonin treatment also suppressed, in a dose related manner, the rise in plasma prolactin under the lengthening photoperiod. We conclude that the dose-related efficacy of melatonin could be ascribed to the difference in the diurnal profiles of circulating melatonin.

Administration, Oral↗
PubMed1991

Steel-Dickie (Sld) mutation affects both maintenance and differentiation of testicular germ cells in mice.

The effects of Steel-Dickie (Sld) mutations on testicular germ cell differentiation were investigated using experimental cryptorchidism and its surgical reversal in mutant, C57BL/6-Sld/+ and wild-type C57BL/6- +/+ mice. In Sld/+ cryptorchid testes the maintenance of undifferentiated type-A spermatogonia was impaired and their numbers decreased. In contrast, the proliferative activity of type-A spermatogonia in the cryptorchid testis of mutant mice appeared normal as judged by their progression through the cell cycle. Surgical reversal of cryptorchidism resulted in regenerative differentiation of mature germ cells in +/+ testes. However, the regenerative differentiation of type-A spermatogonia which remained in Sld/+ cryptorchid testes was strongly impaired, particularly at two steps of cellular differentiation, from type-A spermatogonia to intermediate or type-B spermatogonia and at meiotic division. Furthermore, in mutant mice, no significant recovery of testicular weight was observed after surgical reversal compared with +/+ mice.

Animals↗
PubMed1991

Differential effects of epidermal growth factor on the differentiation of type A spermatogonia in adult mouse cryptorchid testes in vitro.

The effect of epidermal growth factor (EGF) on testicular germ cell differentiation was investigated. Testicular fragments from surgically prepared cryptorchid testes of adult mice were cultured for 9 days in serum-free media containing various concentrations of EGF. Histological sections of testis were examined under a light microscope and each type of germ cell and mitotic cell in the seminiferous tubules was counted per 1000 Sertoli cells. EGF at concentrations ranging from 100 to 200 ng/ml induced differentiation of type A spermatogonia. The observed maximal stimulatory activity of EGF at a concentration of 100 ng/ml was 30% of the positive control cultures treated with calf serum. EGF at concentrations ranging from 1 to 100 ng/ml significantly inhibited the mitotic activity of FSH, FSH plus retinol, or FSH plus fetuin on type A spermatogonia and their differentiation. The number of type A spermatogonia in testes cultured with FSH, FSH plus retinol, or FSH plus fetuin decreased when EGF was added. On the other hand, EGF stimulated the differentiation of type A spermatogonia induced with fetuin but did not influence retinol-induced differentiation. It is proposed that EGF inhibits testicular germ cell differentiation by blocking the proliferation of type A spermatogonia stimulated by FSH.

Animals↗
PubMed1991

[New in situ hybridization technique with non-radio-labeled probe--detection of choline-acetyltransferase gene expression in rat spinal cord].

We have established a new in situ hybridization method utilizing non-radiolabeled probes. Using this technique, we have attempted to detect the choline-acetyltransferase (ChAT) gene expression in rat spinal cord. It was revealed that the ChAT gene was expressed mainly in the cytoplasm of motor neurons and para-central cells. On the other hand, ChAT protein has already been reported to exhibit a diffused distribution in the cholinergic fibers. Comparing the localization of the ChAT gene with that of the ChAT protein, the ChAT gene was shown to exist only in the cytoplasm surrounding the nuclei. However, the ChAT gene was not expressed in axon terminals where ChAT protein synthesized acetylcholine. This result indicates that the ChAT gene is translated into protein around the nuclei and is thereafter transported toward the action site. We now think that there are two different patterns of neurotransmitter gene distribution. After mRNA is translated into protein, this protein is carried to the action site. On the other hand, mRNA itself is delivered to the action site and translated into protein. After the translation, this protein form exerts its own function. The ChAT gene is suspected as belonging to the first category of gene distribution. In Alzheimer disease, not only the acetylcholine system but also its biosynthetic enzyme, ChAT, system are supposedly destroyed by an unknown factor. If we can clarify the regulatory mechanism of the ChAT gene, this will lead us to the molecular pathogenesis of Alzheimer disease. Additionally, this new in situ hybridization technique should shed some light on the complex brain networks.

Animals↗
PubMed1991

[An unusual case of superior sagittal sinus thrombosis accompanied with dural AV fistula].

Benign intracranial hypertension or pseudotumor cerebri is an collective term for a number of diverse syndromes characterized by increased intracranial pressure. Neither intracranial mass nor ventricular dilatation is observed in this disorder. Moreover, the pathogenesis of this syndrome has yet to be determined. We report a case of 36-year-old female diagnosed as benign intracranial hypertension, who has developed superior sagittal sinus thrombosis and dural AV fistula during the follow up period. The patient was pointed out to have papilledema and elevated intracranial pressure six years ago. Although she was examined by both DSA and CT scan, no abnormal intracranial lesions were observed. Consequently, she was diagnosed as the benign intracranial hypertension and had been followed as an out patient. Three years later, lumboperitoneal shunting was performed because of severe headache and visual impairment. Postoperatively, the patient had been well for two years. Recently, occipital headache recurred and she was readmitted to our hospital. MRI studies demonstrated dilated vessels in the right occipital area. Additionally, angiograms revealed not only the superior sagittal sinus thrombosis but also the rich network of dural AV fistula adjacent to the occlusion. According to those results, the superior sagittal sinus was supposed to have the incomplete occlusion or delayed blood flow that were not observed by DSA, MRI and CT scan performed previously. Those occlusive change in the superior sagittal sinus impeded the CSF absorption and elevated the pressure of venous inflow, then the arterio-venous communication has been developed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Effects of a membrane-bound trypsin-like proteinase and seminal proteinase inhibitors on the bicarbonate-sensitive adenylate cyclase in porcine sperm plasma membranes.

Plasma membranes were purified from flagella of porcine cauda epididymal sperm and proteolytic regulation of bicarbonate-sensitive adenylate cyclase was studied. It was found that the epididymal sperm plasma membrane contained a trypsin-like proteinase which inactivated adenylate cyclase. Bicarbonate activates adenylate cyclase as reported previously, but, at the same time, the anions enhance the inactivation of the enzyme by the membrane-bound trypsin-like proteinase. This phenomenon is not due to the direct activation of the proteinase, but closely related to the activation of adenylate cyclase by bicarbonate. It was also found that seminal proteinase inhibitors blocked the inactivation of adenylate cyclase and maintained the bicarbonate activation of the enzyme at high level. Actually, bicarbonate keeps adenylate cyclase fully active in ejaculated sperm, because membrane-bound proteinase is completely inhibited by the seminal proteinase inhibitors. These results suggest that the interactions between membrane-bound proteinase and seminal proteinase inhibitor are involved in the regulation of the bicarbonate-sensitive adenylate cyclase system.

Adenylyl Cyclase Inhibitors↗
PubMed1990

The enhancing effects of anion channel blockers on sperm activation by bicarbonate.

We found that anion channel blockers such as phosphotungstate and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS) enhanced HCO3(-)-induced activation on porcine epididymal sperm. In the presence of these compounds, HCO3- increased the motility, respiration rate and especially the cAMP content of the sperm to a greater extent than did HCO3- alone. The enhancing effects were not observed in the absence of HCO3-, but were evident when the concentration of HCO3- was low. These compounds did not significantly alter the intracellular pH and did inhibit the adenylate cyclase activity of the sperm plasma membrane. When these compounds were added to sperm homogenate with ATP, the cAMP formed was reduced compared to the control. In addition, these compounds inhibited both the SO4(2-) influx and efflux of the sperm. From these results, we conclude that the anion channel blockers tested principally inhibit the efflux of endogenous HCO3- derived from metabolic CO2, so that HCO3- accumulates intracellularly and stimulates the adenylate cyclase of the sperm.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1990

Phosphotungstate as a useful eluent for antithrombin III purification by heparin-agarose affinity chromatography.

We have recently found that phosphotungstate (PTA) has a heparin-like anticoagulant effect. In the present paper, we studied whether PTA is useful as an eluent of antithrombin III (ATIII) on heparin-Sepharose affinity chromatography. Human ATIII adsorbed on the heparin-Sepharose gel was eluted with NaCl buffer at the NaCl level of 1M. Whereas, PTA could elute ATIII at the level of less than 1mM and thus obtained ATIII fraction contained less impurities than such a fraction eluted with NaCl. Residual PTA in the eluate was easily decomposed by alkalization, being convenient for subsequent studies.

Antithrombin III↗