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Biomedical subjects

T Miyagi

Publications and source records attributed to T Miyagi.

At least 73 records · Page 4Linked to original sources

Posttraumatic edema in the corpus callosum shown by MRI.

MRI was performed on 120 patients who sustained closed head injury of varying severity. Patients ranged in age from 4 to 87 years (average, 32 years). All patients had an initial MRI within 28 days (median 12 days) of injury. MRI disclosed areas of abnormal signals in the corpus callosum of 21 (18%) of the 120 patients; 1 (2%) of the 44 patients who sustained mild injuries (GCS > or = 13), 3 (10%) of the 31 moderate injuries (GCS 9-12), and 17 (38%) of the 45 severe injuries (GCS < or = 8) (p < 0.0001). All but 2 of the 21 patients with corpus callosum lesions had other parenchymal lesions that were visualized by MRI. Of these 21 patients, MRI was repeated in 19. In 13 of the 19 patients, repeat MRI scans at 25 to 42 days after injury showed the disappearance of lesions that had on the first MRI shown a high signal on T2-weighted and FLAIR images and a normal signal on T1-weighted images. The MRI findings and time source of the disappearance of the corpus callosum lesions mirrored those of paracontusional edema in the subcortical white matter. Patients in whom the corpus callosum lesion disappeared had a better outcome than those in whom the lesion remained (good recovery/moderate disability; 92% vs 63%). The present MRI results suggest that some lesions in the corpus callosum following closed head injury are reversible, thus resembling edema that may be produced by a relatively mild shear strain force to the corpus callosum.

Adolescent↗

Immunohistochemical evidence for the existence of rat cytosolic sialidase in rat skeletal muscles.

Histochemical evidence is required to demonstrate the presence of biochemically defined cytosolic sialidase. To meet this requirement, we examined the immunohistochemical localization of the enzyme in rat skeletal muscles. Sections of chemically fixed tissues were incubated with a polyclonal antibody raised against a synthetic peptide which corresponded to a part of the enzyme protein. After incubation with the primary antibody, cryosections for fluorescence microscopy and resin sections for electron microscopy were incubated with a fluorochrome- and colloidal gold-labeled secondary antibody, respectively. Immunofluorescence was diffusely distributed in the muscle fibers and was also found in the perimysium and blood vessels. Many immunogold particles were scattered over the sarcoplasm, myofibrils, nucleoplasm, and matrix of mitochondria. The immunogold particles were also found in the equivalent compartments of axons, Schwann cells, and cells of endomysium and blood vessels. The specificity of the primary antibody was elucidated by immunoblotting and an immunoprecipitation test. These findings clearly indicate that this type of sialidase is essentially located in the cytosolic compartment. Consequently, the name, cytosolic sialidase, will be appropriate for this enzyme. Additionally it is indicated that this enzyme is also present in cells other than skeletal muscle fibers.

Animals↗

Prolonged isoflurane anesthesia in a case of catastrophic asthma.

A 13-year-old female patient with life-threatening asthma was treated with the inhalational anesthetic agent, 1% isoflurane, for 202 h (140 minimum alveolar concentration (MAC) hours). The patient survived and exhibited no significant side effects attributable to the medication. The present patient report provides additional clinical information supporting the utilization of long-term isoflurane general anesthesia in the management of refractory status asthmaticus that have not responded to aggressive medical management.

Acute Disease↗

[Glycohistochemical analysis of apoptotic bodies in eyelid tumor].

To clarify the relation between the mechanism of apoptosis in tumor tissues and sialic acids on the termini of sugar chains of glycoconjugates, a case of squamous cell carcinoma was examined using immunohistochemistry and glycohistochemistry. Immunohistochemistry and in situ hybridization histochemistry suggested that sialylation by the sialyltransferase in dominant in tumor cells, whereas hydrolysis of sialic acids by the sialidase is dominant in apoptotic bodies. Lectin histochemistry revealed that sialic acid alpha 2, 3 galactose beta 1, 3 N-acetylgalactosamine (Gal beta 1, 3 GalNAc) is present on the surfaces of tumor cells, and Gal beta 1, 3 GalNAc is present on those of apoptotic bodies. The exposed Gal beta 1, 3 GalNAc owing to the decrease in sialic acids on the surfaces of apoptotic bodies may be recognized by the C-type lectin on the macrophage for phagocytosis.

Aged↗

[Immunohistochemical localization of cytosolic sialidase in the epithelium of rat cornea and conjunctiva].

The binding sites of the anti-cytosolic sialidase antibody and Maackia amurensis lectin II (MAL II: specific for sialic acid alpha 2, 3 galactose) in the epithelium of the rat cornea and conjunctiva were immunohistochemically and lectin-histochemically examined, respectively. Cytosolic sialidase was detected in the cytoplasm of the middle and basal epithelium of the cornea and conjunctiva, whereas MAL II bound to the apical region of their epithelium and the mucous of the goblet cells. The predominant action of the cytosolic sialidase, which is stronger than that of the sialyltransferase, may inhibit the terminal sialylation of the glycoconjugates at the middle and basal regions of the epithelium of the cornea and conjunctiva.

Animals↗

In vitro interleukin 12 activation of peripheral blood CD3(+)CD56(+) and CD3(+)CD56(-) gammadelta T cells from glioblastoma patients.

Interleukin (IL)-12 has recently been shown to be directly involved in the activation of natural killer and alphabeta T cells via an IL-2-independent pathway. We show here that another type of human cytotoxic cell, gammadelta T cells activated by solid-phase anti-CD3 antibody and expanded using IL-2, obtained, in this case, from the peripheral blood of glioblastoma patients, displays significant tumoricidal activity. In addition, its cytotoxic activity against K562 or Daudi cells or against autologous glioblastoma targets (but not lymphocytes) is significantly enhanced when costimulated with IL-2 and IL-12. To study this synergistic activation by the two interleukins of the patients' gammadelta T cells, we screened the cells for the presence of the IL-2 receptor (IL-2R) and IL-12 receptor (IL-12R) using both flow cytometric analysis and PCR. The patients' gammadelta T cells constitutively expressed the high-affinity IL-2R; when stimulated with IL-12 plus IL-2, the levels of IL-2Ralpha and IL-2Rbeta increased, whereas that of IL-2gamma did not. They also expressed marginal levels of low-affinity IL-12R both immediately after IL-2 expansion and after 24-h incubation, and significantly higher levels after 72-h incubation, consistent with the level of gammadelta T-cell activation. IL-12 alone induced little proliferation of patients' gammadelta T cells in a 24-h assay and none in a 72-h assay; however, it caused a marked inhibition of the IL-2-induced proliferative response in the 72-h assay. The synergistic action of IL-2 and IL-12 was completely abolished by combined pretreatment with anti-IL-2alpha, beta, and gamma mAbs. IL-12-mediated enhancement of gammadelta T cell cytotoxic activity was inhibited by anti-IL-2Rbeta mAb in a dose-dependent manner but not by anti-IL-2Ralpha or anti-IL-2Rgamma mAbs. Thus, the increased expression of the IL-2Rbeta is critical for the synergistic activation of gammadelta T cells by IL-12 plus IL-2; it is also probable that at least the low-affinity IL-12R contributes to the activation of gammadelta T cells mediated by either IL-12 alone or IL-12 plus IL-2. We have, therefore, demonstrated that IL-12 can stimulate the cytotoxic activity of gammadelta T cells from glioblastoma patients, acting via the IL-2Rbeta component of the IL-2R and low-affinity IL-12R. IL-12 activation of patients' gammadelta T cells could possibly be of potential use in the treatment of glioblastoma patients.

Antigens, CD↗

Involvement of an endogenous sialidase in skeletal muscle cell differentiation.

We have previously observed that the cytosolic sialidase gene is highly expressed in rat skeletal muscle and that it contains an enhancer/promoter region which is transcriptionally active in rat L6 myogenic cells. Here we present evidence for the involvement of cytosolic sialidase in myoblast differentiation. During L6 myoblast differentiation induced by serum depletion, cytosolic sialidase is increased in activity as well as in terms of mRNA level. Sialidase activity is essentially lacking in untreated myoblasts but appears concomitantly with myotube formation after induction of differentiation. The mRNA becomes able to be detected after 3 days at the time which myogenin mRNA reaches a maximum level. Myotube formation can, in fact, be blocked by the addition of an antisense oligodeoxyribonucleotide complementary to the first 8 codons of the cytosolic sialidase.

Animals↗

Immunohistochemical localization of cytosolic sialidase in photoreceptor cells.

The binding sites of the antibody to cytosolic sialidase on the rat and monkey photoreceptor cells were examined immunohistochemically using the avidin-biotinylated peroxidase method. In the rat photoreceptor cells, the antibody bound diffusely to the inner segment and the outer nuclear layers which are composed chiefly of rod cells. In the monkey photoreceptor cells, the antibody bound to the rod inner segments which were clearly distinct, morphologically, from the cone inner segments. The antibody also bound to the rod cell bodies in the outer nuclear layer. These binding patterns show that the antibody bound preferentially to rod photoreceptor cells. This observation is consistent with previous lectin histochemical findings that sialoglycans are preferentially present on the surfaces of rod photoreceptors, and in the rod-associated interphotoreceptor matrix. Sialidase in rod inner segments may function by balancing with sialyltransferase, also preferentially expressed in rod inner segments, to form sialyl residues on the termini of sugar chains in the rod-associated sialoglycoconjugates.

Animals↗

[Choroidal epithelial cyst of the quadrigeminal plate].

A case of choroidal epithelial cyst of the quadrigeminal plate is reported. A twenty-five-year-old man was admitted to our department because of Parinaud's sign and intermittent headache. CT and MRI showed a cyst in the posterior part of the third ventricle. Left occipital transtentorial approach was carried out and the wall of the cyst was subtotally removed. The cyst contained watery clear fluid. On light microscopy, the cyst wall consisted of a single layer, flat epithelial cells and thick collagenous connective tissue. An electronmicroscopic study revealed that the epithelial cells rested on a basement membrane separating them from the underlying collagenous tissue. Microvilli without coating material were presented on the surface of the cells. With this data in hand, the cyst was considered to originate from the developing choroid plexus.

Adult↗

[A case of ureteropelvic junction stenosis accompanied by a valve-like structure in the renal pelvis].

A 9-year-old girl visited our clinic with recurrent high fever as her chief complaint. Her excretory urogram showed only a few dilated upper calyces. Retrograde pyelography revealed ureteropelvic junction stenosis with hydronephrosis, so that the ureteral catheter could not be passed through the ureteropelvic junction. A fold-like filling defect was also seen above the ureteropelvic junction. At operation the ureteropelvic junction was found to be markedly obstructed, and a semilunar valve-like structure was also observed above it. The valve-like structure was seen where the fold-like filling defect appeared on the retrograde pyelogram. En bloc resection of the lower part of the renal pelvis with the valve-like structure and the ureteropelvic junction was performed, followed by dismembered uretero-pyeloplasty. Histologically, the valve-like structure was a transverse mucosal fold with a muscle layer and without adventitia. Many cases of ureteral valves have been reported, but none with valves or valve-like structures within the renal pelvis as in our case.

Child↗

Inactivation of the DCC tumor suppressor gene in a B-cell lymphoma cell line with the alteration of chromosome 18.

A B-cell lymphoma cell line, designated KML-1, was established from pleural effusion of a patient with non-Hodgkin's lymphoma of large-cell type. The lymphoma arose in the pelvis and ran an aggressive clinical course. Chromosome analysis of the cell line exhibited a complex karyotype including the loss of chromosome 18. To evaluate the molecular events in the cell line that may be associated with the development of the lymphoma, we investigated the expression and/or alterations of several classes of human genes, including oncogenes, tumor suppressor genes, and cytokine genes. The expression of the DCC (deleted in colorectal cancer) gene, located on the chromosome 18q21, was extremely reduced in KML-1 cell line, as compared with that in a normal spleen tissue and other 4 lymphoma cell lines by the reverse transcription-polymerase-chain-reaction (RT-PCR) method. This finding suggests that inactivation of the DCC gene might play a role in the pathogenesis of the case of lymphoma.

Adult↗

Genomic organization and the 5'-upstream sequence of the rat cytosolic sialidase gene.

We have previously cloned a cDNA of a rat cytosolic sialidase which is strongly expressed in skeletal muscle. Both the highest enzyme activity, as well as the highest mRNA level, are present in this tissue. To understand the basis of the expression of this sialidase, we have cloned and sequenced the rat gene and its 5'-upstream region from a rat genomic library. The gene encoding the 1.8 kb skeletal muscle mRNA was found to span 3.4 kb of genomic DNA, and to consist of two introns and three exons. Exon 1 contains the 5' noncoding region, and exons 2 and 3 encode the regions containing the AUG initiation codon and two Asp-boxes, respectively. In the 5'-upstream sequence, there are a TATA box and two E-box pairs known as consensus binding sites for muscle-specific transcription factors. Analysis of the expression of transfected sialidase enhancer/promoter expression plasmid demonstrated the sialidase enhancer/promoter to be active in rat L6 myogenic cells shown to express this gene, but inactive in rat 3Y1 fibroblasts shown not to express the enzyme. The transcription activity was increased 3-fold after induction of myoblast differentiation by serum depletion. These observations give an account of constitutive expression of the sialidase gene in skeletal muscle.

Amino Acid Sequence↗

Establishment of novel lymphoid cell lines dually infected with human T cell lymphotropic viruses types I and II.

With the goal of establishing an in vitro system of dual infection with human T cell lymphotropic viruses (HTLV) types I and II, rabbit lymphocytes were cocultured with a mixture of lethally irradiated HTLV-I-producing Ra-1 and HTLV-II-producing RII cell lines. This gave rise to a lymphoid cell line, RW-1, that was dually infected with HTLV-I and -II as detected by immunofluorescence staining, electron microscopy, and polymerase chain reaction using primers specific for the pol and env regions of each virus and by Southern blot hybridization. Two clonal cell lines derived from RW-1 were also coinfected with the viruses, indicating that dual infection had occurred at the single cell level. The coinfection could be readily propagated to fresh lymphocytes by coculture with RW-1. In contrast, attempts to superinfect HTLV-I-infected lymphoid cell lines with HTLV-II and vice versa were consistently unsuccessful, suggesting receptor interference between HTLV-I and -II.

Animals↗

[Continent urinary diversion with the Florida pouch].

From October 1990 through June 1993, the Florida pouch, a continent urinary reservoir using the ascending colon and the dexter half of the transverse colon was constructed in 7 patients after cystectomy for invasive tumor. Concerning the length of the efferent limb, although 10 cm was adopted in the first three cases, we shortened it and finally considered 8 cm to be the adequate length. Although the capacity of the reservoir ranged from 90 ml to 180 ml immediately after operation, an increase of capacity by three times or more within three months after operation was seen. The patients performed self-catheterization 4-5 times during the day and 0-2 times at night for volumes ranging from 300 to 600 ml. Continent colonic urinary diversion did not appear to create either any significant acid-base changes or azotemia in patients with normal renal function. Every patient received both a serum value evaluation and an absorption test for vitamin B12 (Schilling test). Although there were no patients with a reduced serum vitamin B12 level, one patient showed a slightly low absorption value. Because there is a large quantity of vitamin B12 reserve in the liver, it must be emphasized that even when the entero-hepatic circulation has been injured by surgical interruption of the intestinal tract, it may be years before reduced serum vitamin B12 value become apparent. Accordingly, the vitamin B12 absorption test should be performed regardless of the ileal length incorporated into the resection.

Aged↗