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Biomedical subjects

Y Tajima

Publications and source records attributed to Y Tajima.

At least 19 recordsLinked to original sources
PubMed1992

Loss of sperm in juvenile spermatogonial depletion (jsd) mutant mice is ascribed to a defect of intratubular environment to support germ cell differentiation.

C57BL/6(B6)-jsd/jsd mice are sterile due to the defective spermatogenesis in the testes. To know the cause of the deficient spermatogenesis in B6-jsd/jsd mice, we examined whether the problem is within or outside the seminiferous tubules by transplanting tubules from cryptorchid testes of B6- +/+ mice into B6-jsd/jsd testes or tubules from B6-jsd/jsd mice into testes of (WB x C57BL/6)F1-W/Wv (hereafter, WBB6F1-W/Wv) mice. Type A spermatogonia differentiated into spermatids in seminiferous tubules from cryptorchid testes transplanted into B6-jsd/jsd testes. In contrast, in B6-jsd/jsd tubules transplanted into WBB6F1-W/Wv testes, type A spermatogonia were stimulated to mitotic proliferation, but didn't proceed to any differentiated germ cells. The present results suggest that the cause of the deficient spermatogenesis in B6-jsd/jsd mice is a defect of intratubular environment to support germ cell differentiation.

Animals↗
PubMed1992

In vivo effects of tunicamycin on chondrocytes of rat mandibular condyles as revealed by lectin cytochemistry.

The in vivo effects of tunicamycin on the glycosylation of proteoglycans and link protein in rat mandibular condylar chondrocytes were studied by ultrastructural lectin histochemistry. The binding of wheat-germ agglutinin was shown by using anti-lectin antibody followed by protein A-gold complex. In normal rats, wheat-germ agglutinin labeling was restricted to trans cisternae and vacuoles of the Golgi complex, whereas it was observed in neither the cis region of the Golgi complex nor in the rough endoplasmic reticulum. By 3 h after the drug administration, wheat-germ agglutinin binding sites on the disorganized Golgi vacuoles were dramatically reduced in number. At 6 h after the drug administration, the lectin binding sites on the Golgi vacuoles were restored. These results demonstrate that the in vivo use of tunicamycin in combination with histochemical analysis using lectin probes is of significant value for the study of protein glycosylation in chondrocytes of the rat mandibular condyle.

Animals↗
PubMed1992

Positive and negative feedback regulation of choline acetyltransferase mRNA levels in Drosophila: a study using temperature-sensitive mutants and embryo cell cultures.

Steady state levels of the mRNA coding for the neurotransmitter biosynthetic enzyme, acetylCoA-choline-O-acetyltransferase (ChAT, EC 2.3.1.6), were measured in wild type Drosophila and two temperature-sensitive mutants (Chats1 and Chats2) using the RNase protection method. At a permissive temperature the relative amounts of ChAT mRNA were: wild type: Chats1:Chats2 = 1:2.09 (+/- 0.39):3.37 (+/- 0.57) (mean +/- S.E.M.) indicating that mutant flies may compensate, for making a thermolabile form of enzyme, by producing and/or maintaining higher levels of ChAT mRNA. At a restrictive temperature the ChAT mRNA levels decreased in both mutants and increased in wild type flies. The regulatory mechanism(s) responsible for increasing ChAT mRNA in wild type flies appears to have failed in the mutants at high temperature. Steady state mRNA levels were also measured in embryonic cell cultures prepared from wild type embryos. Cultures grown in the presence of two pharmacologic agents (carbamylcholine and d-tubocurarine) which should interfere with cholinergic neurotransmission, showed less mRNA resulting from a decrease in levels of ChAT gene transcription. Our results imply that neurotransmission and the rate of neurotransmitter biosynthetic enzyme gene transcription are coupled for the cholinergic system in Drosophila.

Alleles↗
PubMed1992

Cylindrical cell papilloma of the nasal cavity and paranasal sinuses. A histochemical and cytochemical study.

A cylindrical cell papilloma occurring in the sino-nasal mucosa of a 61-year-old woman was studied histochemically at both light and electron microscopic levels. The cylindrical cells demonstrated distended intracytoplasmic microcysts with numerous microvillous projections on the apical cell membrane. The retained mucosubstance in the cystic spaces stained intensely with HID-TCH-SP sequence and showed no apparent communication with the extracellular space. These findings indicate that the cylindrical cells may be of mucous-secreting cell derivation, being derived from cells possessing abnormal and/or failed secretory function. The property of sulfated mucin in the 'cylindric' intracytoplasmic cysts is suggested to be the result of endodermal displacement or metaplasia of the Schneiderian epithelium.

Female↗
PubMed1992

An improved method for the serotyping of free coagulase from Staphylococcus aureus.

The serotyping of free coagulase, one of the most reliable ways to identify strains of Staphylococcus aureus, and widely employed in Japan, has been improved by adding magnetite sand to the reaction mixture. Culture medium supernatant and a type-specific antibody are mixed in a well of a microtiter plate, and plasma-enriched bovine fibrinogen is treated with magnetite sand. The use of tranexamic acid and gum arabic in the reaction mixture also increases the sensitivity of the reaction. Finally, the plate is placed on a magnetic stirrer. If the type of the coagulase corresponds to that of the antibody, no clot formation will occur, and this is easily confirmed by the movement of the sand. Although the amount of reaction mixture required is much less than that for the conventional tube method, our new method is able to detect slight increases in viscosity of the reaction mixture due to fibrin formation even before complete clotting occurs, thus providing very high sensitivity. Clot formation can also be judged by observing a turbid mass of fibrin in the well (Hwang's method), but this approach is a little slower than our method involving immobilization of magnetite sand.

Coagulase↗
PubMed1992

Hepatocellular carcinoma containing endocrine cells. An autopsy report of triplecancer involving the liver, kidney and thyroid.

An autopsy case of triplecancer (hepatocellular carcinoma of the liver, renal cell carcinoma of the kidney, and papillary carcinoma of the thyroid) was reported. Histological features of primary hepatic tumor suggested undifferentiated hepatocellular carcinoma (Edmondson-Steiner's Grade IV). However, certain tumor cells showed distinctive argyrophilic reactions and electron microscopy revealed small round granules resembling electron dense endocrine secretory granules in their cytoplasm. Immunohistochemistry demonstrated that tumor cells showed a positive reaction for AFP while some others were positive for chromogranin-A. Immunohistochemical demonstration of AFP production by tumor cells indicated their hepatocyte origin. No endocrine syndrome had been present and no alternative primary source of the endocrine tumor was detected. Tumors of the kidney and thyroid were considered to be incidentally combined.

Aged↗
PubMed1992

Effects of W (c-kit) gene mutation on gametogenesis in male mice: agametic tubular segments in Wf/Wf testes.

Mutations of the W (c-kit) gene, which encodes a transmembrane tyrosine kinase receptor, affect the development and differentiation of many types of stem cell. Most homozygous W mutant mice are sterile, due to a lack of germ cells arising during embryonic development, but one of the notable exceptions is Wf/Wf mice, which are fully fertile in both sexes. In order to elucidate the effects of the Wf mutation on spermatogenesis, postnatal spermatogenesis in Wf/Wf mice was histologically examined. The number of gonocytes at birth was significantly reduced and small portions of agametic seminiferous tubule segments were observed in mutant mice. It is suggested that this is due to a deficiency of primordial germ cells (PGC). Other than the agametic tubules, there was no evidence of reduced spermatogenesis after birth. These results indicate that the function of the W (c-kit) gene is more necessary for the development of PGC than for postnatal germ cells.

Animals↗
PubMed1992

A new animal model of non-insulin-dependent diabetes mellitus induced by the NDK25 variant of encephalomyocarditis virus.

Intraperitoneal inoculation with NDK25, a variant of Encephalomyocarditis (EMC) virus which has been newly cloned from the M variant of EMC virus (EMC-M), caused DBA/2 mice to develop noninsulin-dependent diabetes mellitus. The NDK25-infected mice demonstrated abnormal glucose tolerance from 1 to 3 weeks after inoculation. The infection resulted in mild insulitis and the destruction of pancreatic beta cells at 1 week after inoculation and led to a significant reduction in the insulin content of the pancreas, but there was no ketonuria. The insulin content of the pancreas was recovered considerably from 15 +/- 3 at 1 week to 95 +/- 16 micrograms/g pancreas at 12 weeks, although the latter value was still significantly lower than that of the control mice (P < 0.05). Under microscopy, mild and partial infiltration of mononuclear cells was observed in about half the pancreatic islets only 1 week after inoculation, and then disappeared. Thus, we believe we have established a new model of noninsulin-dependent diabetes mellitus using the NDK25 variant of EMC virus.

Animals↗
PubMed1991

Purification of bicarbonate-sensitive sperm adenylylcyclase by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid-affinity chromatography.

Anion transport inhibitors, such as SITS (4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid) and heparin, inhibit reversibly the bicarbonate-sensitive adenylylcyclase of porcine sperm plasma membrane. In the light of this, SITS- and heparin-affinity chromatographies were applied in order to purify sperm adenylylcyclase. SITS-Affi-Gel 102 binds proteins extracted from the porcine cauda epididymal sperm plasma membrane by Lubrol-PX, more selectively than heparin-agarose. However, recovery of adenylylcyclase activity is higher when heparin-agarose is used. The hormone-sensitive liver adenylylcyclase, which is less sensitive to bicarbonate than sperm enzyme, has less affinity for these affinity resins than sperm enzyme. Adenylylcyclase can be purified to apparent homogeneity on two-dimensional gel electrophoresis (isoelectric focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis) from the Lubrol-PX extract of the purified sperm plasma membrane by using SITS-affinity chromatography at the first step of the purification followed by preparative isoelectric focusing and gel filtration. The molecular weight and pI of the purified enzyme are 46,300 and 6.9, respectively. The purified enzyme activity is highly dependent on Mn2+. Bicarbonate activates even the purified enzyme both by decreasing Km and by increasing Vmax.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
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↗