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Biomedical subjects

I Ishida

Publications and source records attributed to I Ishida.

At least 55 records · Page 3Linked to original sources
PubMed1995

Resistance against multiple plant viruses in plants mediated by a double stranded-RNA specific ribonuclease.

Many plant viruses have single-stranded RNAs as their genomes. During the course of replication, genomic RNAs and their complementary template RNAs are likely to form double-stranded (ds) RNA at least transiently. To attack replication intermediates of many plant RNA viruses specifically, we introduced a yeast-derived ds-RNA specific RNase gene called pac 1 into plants. The transformed plants showed a decrease in lesion numbers when they were challenged with tomato mosaic virus, and a delay in the appearance of symptoms when inoculated with cucumber mosaic virus or potato virus Y.

Mosaic Viruses↗
PubMed1994

Case report: Wegener's granulomatosis accompanied by communicating hydrocephalus.

A case of Wegener's granulomatosis (WG) accompanied by communicating hydrocephalus is described. An elderly woman with rapidly progressive renal failure was referred to the authors' hospital. Renal histologic study showed necrotizing granulomatous glomerulonephritis with some multinucleated giant cells, which suggested a diagnosis of WG. After admission, a gait disturbance, incontinence, and dementia developed in the patient. Diagnostic procedures including lumbar puncture, computed tomography (CT), and scintigraphy showed findings compatible with communicating hydrocephalus with a normal cerebrospinal fluid (CSF) pressure. Removal of 20 mL of CSF led to a marked improvement in symptoms. Because the presence of subarachnoid hemorrhage, meningitis, and brain tumor was excluded, the final diagnosis was communicating hydrocephalus secondary to WG.

Aged↗
PubMed1992

Effects of a new calcium antagonist, manidipine, on the renal hemodynamics and the vasoactive humoral factors in patients with diabetes mellitus.

The effects of manidipine (10 mg/day for 7 days) on the renal hemodynamics and vasoactive humoral factors were examined in 6 adults with diabetes mellitus (DM). Mean duration of DM was 9 +/- 2 years; serum creatinine concentration was 0.9 +/- 0.04 mg/dL. Plasma endothelin-1 (ET-1) concentration was 5.4 +/- 0.7 pg/mL before manidipine, compared with 1.9 +/- 0.2 pg/mL in 14 controls (p = 0.03%). Systolic and mean blood pressure decreased significantly during treatment without changes in glomerular filtration rate, renal plasma flow, or filtration fraction. Renal vascular resistance tended to decrease and fractional excretion of sodium significantly increased from 1.35 +/- 0.27% to 2.06 +/- 0.47 (p = 2.96%). ET-1 significantly decreased from 5.4 +/- 0.7 pg/mL to 3.5 +/- 0.6 (p = 2.95%), while plasma angiotensin II, atrial natriuretic factor, urinary excretion rate of ET-1, and albumin excretion rate did not change. Manidipine lowers blood pressure without adversely affecting renal function in diabetic patients. Manidipine, which lowers ET-1, may protect from progressive renal injury in diabetics.

Adult↗
PubMed1991

Variation of colony morphology and chromosomal rearrangement in Candida tropicalis pK233.

UV irradiation treatment of the asexual yeast Candida tropicalis gave rise to morphological mutants exhibiting at least four different types of abnormal colonies on glucose-containing solid medium. These mutants were named according to their colony morphologies: 'doughnut', 'frilly', 'echinoid' and 'walnut' mutants. The doughnut mutant produced a wrinkled colony with a hollow in its central region that was rich in filamentous pseudohyphal cells. With increased incubation time, the colony gradually changed to a reticulate shape. The parent strain, which normally produced smooth colonies, gave similar colonies to those of the doughnut mutant when grown in medium containing oleic acid as carbon source. Both the frilly and the walnut mutants produced pseudohyphal cells in a similar fashion to the doughnut mutant. The echinoid mutant produced an echinulate colony morphology with aerial hyphae and contained true hyphal cells as well as pseudohyphal ones. Pulsed-field gel electrophoresis showed that the echinoid and frilly mutants had different karyotypes from that of their parent strain, suggesting the occurrence of chromosomal rearrangements associated with these morphological mutations.

Candida↗
PubMed1990

Transgenic mice demonstrate that epithelial homing of gamma/delta T cells is determined by cell lineages independent of T cell receptor specificity.

gamma/delta T cells with different TCR repertoires are compartmentalized in different epithelia. This raises the possibility that the TCR-gamma/delta directs homing of T cells to these epithelia. Alternatively, the signals that induce TCR-gamma/delta expression in developing T cells may also induce homing properties in such cells, presumably in the form of cell surface receptors. We have examined this issue by studying the homing of gamma/delta T cells in transgenic mice constructed with specific pairs of rearranged gamma and delta genes. In such mice, most gamma/delta T cells express the transgene-encoded TCR. We find that homing to both skin and gut epithelia is a property of T cells and is not determined by the type of gamma and delta genes used to encode their TCR. We also studied the effect of TCR replacement on the expression of Thy-1 and CD8 proteins on the gamma/delta T cells associated with gut epithelia. Our results show that the expression of the appropriate type of TCR-gamma/delta is not required for the Thy-1 expression by these T cells, suggesting that Thy-1 is not an activation marker. In contrast, CD8 expression by gut gamma/delta T cells seems to depend on the expression of the appropriate type of TCR.

Animals↗
PubMed1990

Self-tolerance to transgenic gamma delta T cells by intrathymic inactivation.

During their intrathymic differentiation, T lymphocytes expressing alpha beta T-cell receptors (TCR) are negatively and positively selected. This selection contributes to the establishment of self-tolerance and ensures that mature CD4+ and CD8+ cell populations are restricted by the self major histocompatibility complex. Little is known, however, about gamma delta T-cell development. To investigate whether selection operates in the establishment of the gamma delta T-cell class, we have generated transgenic mice using gamma- and delta-transgenes encoding a TCR that is specific for a product of a gene in the TL-region of the TLb haplotype. Similar numbers of thymocytes expressing the transgenic TCR were generated in mice of TLb and TLd haplotypes. But gamma delta thymocytes from TLb and TLd transgenic mice differed in cell size, TCR density and in their capacity to respond to TLb stimulator cells or interleukin-2 (IL-2). In contrast to gamma delta T cells from TLd transgenic mice, gamma delta T cells from TLb transgenic mice did not produce IL-2 and did not proliferate in response to TLb stimulator cells, but they did proliferate in the presence of exogenous IL-2. These results indicate that functional inactivation of self-antigen-specific T cells could contribute to the establishment of self-tolerance to thymic determinants.

Animals↗
PubMed1990

T-cell receptor gamma delta and gamma transgenic mice suggest a role of a gamma gene silencer in the generation of alpha beta T cells.

A T lymphocyte expresses on its surface one of two types of antigen receptor, T-cell receptor alpha beta or T-cell receptor gamma delta, encoded by a pair of somatically rearranged alpha and beta or gamma and delta genes. It has been suggested that alpha beta T cells are generated only from precursor T cells that failed to rearrange gamma and delta genes in a functional form. However, we found that transgenic mice constructed with functionally rearranged gamma and delta genes produce a normal number of alpha beta T cells. The transgene gamma present in these alpha beta T cells is repressed apparently through an associated cis DNA element (silencer). We propose that some T-cell precursors are committed to generate alpha beta T cells independent of the rearrangement status of their gamma gene and that this commitment involves activation of a factor(s) that interacts with the gamma gene-associated silencer.

Animals↗
PubMed1989

T cell receptor-gamma and -delta genes preferentially utilized by adult thymocytes for the surface expression.

To assess the diversity of gamma delta receptors expressed on adult thymocytes we characterized the gamma- and delta-genes used in a panel of T cell hybridomas expressing a TCR-gamma delta-CD3 complex on the cell surface. DNA cloning and sequencing analysis were necessary to determine the used genes because of the presence of multiple rearrangements in these hybridomas. Among eight hybridomas analyzed, five used V gamma 4, two used V gamma 7, and one used V gamma 6 for gamma-genes, and four used V delta 5, two used V delta 4, and two used V delta 7 for delta-genes. The last delta-gene is documented for the first time. V gamma and V delta appear to pair randomly only restricted by the frequency of the utilization of individual V gamma and V delta segments. These gamma- and delta-genes contained N region addition between the V and J region in most cases. Both D delta 1 and D delta 2 regions were used in the most delta-genes as was seen previously. These results show that certain gamma- and delta-gene segments that are rarely used for the expression on fetal thymocytes are preferentially used by adult thymocytes. Also the repertoire of the gamma delta receptors on adult thymocytes is much greater than that on fetal thymocytes. BW5147 specific V4-C1 gamma-gene was expressed in all of the adult hybridomas. Inasmuch as this gene was not expressed in BW5147 cells or in fetal thymocyte hybridomas expressing V5 or V6 gamma genes, there exists a novel V gene segment-dependent control of transcription in the gamma-gene system.

Aging↗
PubMed1989

Recognition of a self major histocompatibility complex TL region product by gamma delta T-cell receptors.

Ligand specificity of a murine gammadelta T-cell receptor-expressing hybridoma (KN6) derived from adult thymocytes has been analyzed in detail. The molecule recognized by the KN6 gammadelta T-cell receptor is expressed on syngeneic cells of various sources (peritoneal macrophages, thymocytes, spleen cells, and Abelson murine leukemia virus-transformed cell lines) and on transformed cells arrested at an early stage of development (e.g., PCC3 embryonal carcinoma cells). Linkage of the gene coding for the KN6 ligand to the major histocompatibility complex genes could be demonstrated by testing KN6 hybridoma reactivity to cells from congenic strains that differ only at H-2. In addition, analysis of recombinant strains indicates that the gene controlling the KN6 ligand is located in or distal to the TL region. Involvement of the KN6 gammadelta T-cell receptor in this recognition process could be directly demonstrated by transferring the KN6 TL specificity after introduction of the productively rearranged KN6 gamma and delta genes into an alphabeta T-cell clone or into the germ line in transgenic mice. These observations raise the possibility that at least some gammadelta cells regulate hemopoietic cell maturation and activation.

Animals↗
PubMed1989

[Benign superior vena cava syndrome associated with Horner syndrome--report of a case].

Superior vena cava syndrome is commonly caused by malignant diseases such as lung cancer, malignant lymphoma and so forth. It is uncommon that benign diseases obstruct the superior vena cava or its major tributaries. But there are some documented cases of benign superior vena cava syndrome induced by mediastinitis, benign mediastinal tumors, and uncommon lesions having their primary origin in the mediastinum. A 41-year-old male patient had recognized his ptotic palpebra two years ago and chest roentgenographic examination disclosed a tumor shadow occupying the apex of the right thorax but he was almost asymptomatic except venous dilatation of the anterior chest wall. Venography revealed obstruction of the brachiocephalic vein and superior vena cava. At thoracotomy the tumor was found to be impacted at the apex of the thoracic fornix and to be cystic. Primary site of the tumor was at the chest wall and its histological finding was compatible with that of neurilemmoma. Postoperative venography confirmed complete patency of the brachiocephalic vein and superior vena cava.

Adult↗
PubMed1988

Intestinal intraepithelial lymphocytes are a distinct set of gamma delta T cells.

Lymphocytes are most reliably subdivided on the basis of their receptors for antigen at the cell surface. Three subtypes of lymphocytes are well defined: B cells that bear surface immunoglobulin and make antibody, CD4+T cells with CD3 alpha beta receptors specific for antigen associated with class II major histocompatibility complex molecules, and CD8+T cells with CD3 alpha beta receptors specific for antigen associated with class I MHC molecules. These T cells are responsible for known forms of cell-mediated immunity. The discovery of a third rearranging T-cell specific gene called gamma (refs 1 and 2) has revealed the presence of a new class of T cells bearing a new receptor type, CD3 gamma delta (refs 3-7). To date, neither the function nor the specificity of cells bearing this receptor has been determined. Because gamma delta T cells are the main lymphocyte of epidermis, it was proposed that such cells could be important in surveillance of all epithelia. We have isolated intraepithelial lymphocytes from murine small intestine, and shown that they predominantly or exclusively express CD3 gamma delta receptors. Unlike the epidermal lymphocytes, these cells also express CD8, and they use a different V lambda gene to form their receptor. This strongly suggests that gamma delta T cells home in a very specific manner to epithelia, where they presumably mediate their function.

Animals↗
PubMed1988

In situ hybridization demonstrating coexpression of urotensins I, II-alpha, and II-gamma in the caudal neurosecretory neurons of the carp, Cyprinus carpio.

In order to examine the coexpression of different urotensins in the same caudal neurosecretory neurons, in situ hybridization with synthetic oligonucleotide probes specific for mRNAs for urotensins I, II-alpha, and II-gamma (UI, UII-alpha, and UII-gamma) was applied to the caudal neurosecretory system of the carp, Cyprinus carpio, together with immunohistochemistry. Almost all identifiable caudal neurosecretory neurons were labeled with the oligonucleotide and cDNA probes for UI mRNA. Further, any two of the probes for UI, UII-alpha, and UII-gamma mRNAs labeled the same neurons in serial sections. These results suggest that essentially all caudal neurosecretory neurons of the carp coexpress UI, UII-alpha, and UII-gamma. Although most neurons were densely labeled with oligonucleotide probes, only a small portion of the neurons were intensely immunoreactive. This suggests that most caudal neurosecretory neurons actively synthesize all three hormones, but that in some neurons, all or some of the hormones are rapidly transported to the urophysis, resulting in low or undetectable immunoreactivity in the perikarya.

Animals↗
PubMed1988

Early expression of a T-cell receptor beta-chain transgene suppresses rearrangement of the V gamma 4 gene segment.

beta transgenic mice have a T-cell receptor beta-chain gene that is prematurely expressed on the surface of CD4- CD8- thymocytes and paired with an uncharacterized non-T-cell receptor alpha-chain polypeptide. The rearrangement of the T-cell receptor variable region gamma chain gene segment V gamma 4, a component of the gamma-chain gene that is rearranged and expressed preferentially on thymocytes of normal adult mice, is severely repressed in beta transgenic mice. Consequently no gamma delta T-cell receptor heterodimers are detectable on the surface of adult thymocytes or splenic T cells. These results indicate that cells expressing alpha beta or gamma (V gamma 4)-delta TCRs originate from a common precursor in which the first productive rearrangement of either the beta or gamma locus determines the further differentiation pathway into either alpha beta or gamma delta T cells. The repression of V gamma 4 rearrangement by a preexisting beta-chain gene may be indicative of one of several mechanisms which ensure that gamma delta and alpha beta receptors do not as a rule appear on the surface of the same cell.

Alleles↗
PubMed1987

Monoclonal antibodies to monkey brain choline acetyltransferase: production and immunohistochemistry.

Two monoclonal antibodies to monkey brain choline acetyltransferase (ChAT) were obtained. Immunoblot analysis indicated that both antibodies revealed two adjacent protein bands on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis. ChAT was demonstrated immunohistochemically by one of the antibodies in the motoneurons in the monkey brainstem and spinal cord. This antibody also revealed ChAT-positive terminal-like structures in the neuropils of lamina IX of the cervical spinal cord and interpeduncular nucleus.

Animals↗