Biomedical subjects

T Kotani

Publications and source records attributed to T Kotani.

At least 55 records · Page 3Linked to original sources

PubMed2000

Amyloid-producing odontogenic tumor in a Shih-Tzu dog.

A 9-month-old male Shih-Tzu dog had a right mandibular tumor composed of strands, or nest-like proliferation of epithelial cells with abundant fibrous stroma characterized by spheroid to large nodular deposition of amyloid with Congo-red stain. Globule calcification was also seen throughout the tumor tissue and the spheroid depositions often had a concentrically laminated structure (Liesegang rings). The case was diagnosed as amyloid-producing odontogenic tumor in a dog.

Amyloid↗

PubMed2000

Distribution of cells immunopositive for AM-3K, a novel monoclonal antibody recognizing human macrophages, in normal and diseased tissues of dogs, cats, horses, cattle, pigs, and rabbits.

The monoclonal antibody AM-3K, which was developed using human pulmonary macrophages as the immunogen, immunocytochemically labels most human macrophages except for blood monocytes and dendritic cell populations. AM-3K also shows cross-reactivity in some animal species. To evaluate the usefulness of AM-3K, the present study investigated the detailed distribution of AM-3K-immunopositive macrophages in normal and diseased tissues of dogs, cats, horses, cattle, pigs, and rabbits. Zamboni's solution-fixed, paraffin-embedded sections were the most available for the immunocytochemistry with AM-3K. In all animal species examined, AM-3K labeled most macrophages in splenic red pulp, lymph node sinuses and thymus, and tissue macrophages in the interstitium of various organs and sites such as the kidneys, lungs, heart, pancreas, intestines, and skin. Alveolar macrophages and perivascular microglial cells were also immunoreactive for AM-3K. Interestingly, Kupffer cells of dogs, cats, and horses were labeled for AM-3K, but those of cattle, pigs, and rabbits were not. Furthermore, in tumor tissues and inflammatory lesions such as liver fibrosis and encephalomalacia that were obtained from dogs, infiltrating macrophages were stained with AM-3K, but not all infiltrating macrophages reacted to AM-3K. In addition, only 30-50% of pulmonary and peritoneal macrophages obtained from cats and dogs were reactive for AM-3K. AM-3K did not react with blood monocytes, dendritic cell populations, and osteoclasts. These observations indicate that AM-3K specifically labels most exudate and tissue macrophages in the animal species examined. However, the expression of antigens recognized by AM-3K on macrophages may be dependent on differential maturation stages or different functions evoked by some conditions. AM-3K immunoreaction products were seen on the cytoplasmic membrane of macrophages by immunoelectron microscopy. AM-3K would be useful for detection of macrophage populations in the animal species examined here.

Animals↗

PubMed2000

A pleomorphic adenoma of the lacrimal gland in a dog.

A 13-year-old female mongrel dog had a pleomorphic adenoma of the lacrimal gland in the right upper orbit. The tumor measured 3.8 x 3.0 x 3.3 cm, appeared white, round, and firm, and pressed the right globe and surrounding tissues. Histopathologically, the tumor had a thin connective tissue capsule and was composed of tubules with two cell types, some resembling luminal epithelial cells making up the tubular structures and the other of myoepithelial cells. Epithelial tubules were disposed in an adenomatous fashion and separated from each other by proliferating pleomorphic myoepithelial cells. Immunohistochemically, large numbers of the luminal epithelial cells revealed an immunopositive reaction against keratin/cytokeratin (AE1/AE3), and some epithelial cells reacted against cytokeratin 14. Spindle-shaped myoepithelial cells revealed an immunopositive reaction against cytokeratin 14, alpha-smooth muscle actin, and vimentin. A small number of myoepithelial cells reacted against desmin. S-100 protein immunopositivity was frequently found in luminal epithelial cells and rarely in the pleomorphic myoepithelial cells. Glial fibrillary acidic protein positivity was commonly found in myoepithelial cells, myxoid matrices, and intracystic materials, but not in luminal epithelial cells.

Actins↗

PubMed2000

[Anesthetic management of a patient with latex allergy diagnosed preoperatively].

Since the first report in 1979, the number of patients with latex allergy has progressively increased. We experienced an anesthetic management of a 3 year-old child who underwent the repair of anal atresia. The first operation was performed in newborn period. After the surgery, the patient developed skin rash and the loss of consciousness every time anal irrigation was made with latex-containing catheter. Latex-allergy was diagnosed at the age of 3 years, with the positive skin test by latex extract. It took enormous time and efforts to find out the possibility of latex-contamination in a wide variety of medical equipments and supplies to prevent allergic reaction during perioperative period. In this patient, perioperative cause was uneventful. It is suggested that preoperative preparation is essential and caution should be also paid to prevent allergic reaction in daily life.

Anesthesia, General↗

PubMed2000

[Changes of vascular reactivity following esophagectomy measured by near-infrared spectroscopy].

We examined the alterations of peripheral vascular responses following ischemic insult during perioperative period of esophagectomy. Increase of palm blood flow after vascular occlusion, i.e., reactive hyperemia (RH), measured by near-infrared spectroscopy (NIRS) was employed to assess forearm vascular responses. The measurements of RH were performed in esophagectomized patients (n = 12) before induction of anesthesia and postoperatively until the next day of extubation in comparison with normal volunteers (n = 11). After esophagectomy, the RH, which was comparable with those in volunteers, was depressed by 50% on 1 POD, and did not recover until the third POD. In particular, patients receiving laparoscopy-assisted surgery showed less decrease of RH than those receiving the standard open laparotomy. These results suggest that vascular responses to increase blood flow against ischemic insult is depressed following esophagectomy.

Adult↗

PubMed1999

Involvement of gicerin, a cell adhesion molecule, in development and regeneration of oviduct and metastasis of oviductal adenocarcinomas of the chicken.

Gicerin is a novel cell adhesion molecule in the immunoglobulin superfamily and has both homophilic adhesion and heterophilic adhesive activity to neurite outgrowth factor (NOF), an extracellular matrix protein in the laminin family. We investigated the possible involvement of gicerin in oviductal development, regeneration, and metastasis of oviductal adenocarcinomas of the chicken. In the oviductal epithelium, gicerin was expressed strongly during development, disappeared after maturation, and reappeared during regeneration. NOF was constitutively expressed in the basement membrane of the epithelium. These molecules were expressed strongly in oviductal adenocarcinomas in both primary and metastatic lesions in the mesentery. An anti-gicerin antibody inhibited the attachment of adenocarcinoma cells to the mesentery in vitro. Many cells migrated from adenocarcinoma tissues on NOF, which were inhibited by an anti-gicerin antibody. These results suggest that gicerin might play a role in oviductal development and regeneration and also in the metastasis of adenocarcinomas.

Adenocarcinoma↗

PubMed1999

Purification and characterization of lipase from Rhizopus chinensis cells.

Lipase from Rhizopus chinensis cells was purified and characterized. The molecular mass of purified lipase was 28.4 kDa and the optimal temperature and pH for its activity were 37 degrees C and 5.5, respectively. Purified lipase exhibited high hydrolytic activity against fatty acid methyl esters such as methyl caprylate, methyl laurate, and methyl palmitate. Freeze-dried lipase catalyzed the transesterification between olive oil and methyl laurate in n-hexane.

Journal Article↗

PubMed1999

Changes in manganese superoxide dismutase expression after exposure of the retina to intense light.

Manganese superoxide dismutase (Mn-SOD) is a naturally-occurring scavenger of superoxide, one of several reactive oxygen intermediates. To determine if Mn-SOD expression is enhanced as a defensive mechanism against oxidative challenges, such as intense light exposure, rats were exposed to cyclic light (80 lux) for 2 weeks, intense light (1,800 lux) for 24 h, and then again to cyclic light. Experimental and control (exposed to cyclic light only) eyes were enucleated 3 h, 1, 3, 7, and 14 days after light challenge. Protein expression was examined immunohistochemically using rabbit antisera against rat Mn-SOD. There was no significant difference between the light-exposed and the control groups in the thickness of the outer nuclear layers. Both retinal pigment epithelial cells and photoreceptor inner segments in the normal retina were labeled for Mn-SOD. Mn-SOD labeling was lost 3 h and day 1 after light challenge. It was re-expressed in the retinal pigment epithelial cells 3, 7, and 14 days after the light challenge, and in the photoreceptor inner segments after day 14. These results suggest that the retina might have a protective potential against light damage, in which Mn-SOD may play an important role.

Animals↗

PubMed1999

Allogeneic hematopoietic stem cell transplantation for patients with hemophagocytic syndrome (HPS) in Japan.

Seventeen cases (age at onset, 1 month to 18 years; M/F, 9/8) of hemophagocytic syndrome which received allogeneic hematopoietic stem cell transplantation (SCT) in Japan during the period 1988-1998 are reported. The patients consisted of six familial inheritance-proven erythrophagocytic lymphohistiocytosis (FEL), five familial inheritance-unknown and infective agents-unknown HLH (of which two were highly likely to have been FEL with characteristic CNS signs), and six aggressive Epstein-Barr virus (EBV)-related HLH (of which two were natural killer cell-type large granular leukemia/lymphoma-associated hemophagocytic syndrome, EBV-NK-LGLL-HPS). All cases were treated intensively with immuno-chemotherapy, or with chemotherapy before SCT. As sources of SCT, 12 cases received bone marrow cells (sibling six, father one, URD five), two cord blood, two purified CD34-positive cells, and one PBSC. SCTs were successful in all 17 cases, apart from one receiving CD34-positive SCT. Following SCT, four patients relapsed and five died with a median follow-up of 23 months. Among the relapsed cases, the two EBV-NK-LGLL-HPS previously published as successfully transplanted were included. Among the fatal cases, three patients died from relapsed active disease and the remaining two from fatal post-SCT EBV-positive T cell lymphoma and extensive chronic GVHD, respectively. As of the end of September 1998, 10 patients are alive without disease for 3.5 months to 147 months, while two post-SCT patients are still having therapy for residual/recurrent disease. The Kaplan-Meier analysis showed a 2-year event-free survival after SCT as 54.0+/-13.0%.

Adolescent↗

PubMed1999

Dipeptidyl peptidase IV (DPP IV/CD26) staining predicts distant metastasis of 'benign' thyroid tumor.

Because follicular thyroid carcinoma is extremely difficult to diagnose, several cases were encountered which have been rediagnosed as carcinoma due to distant metastasis. In the search for a method of correctly diagnosing 'benign' thyroid tumor, dipeptidyl peptidase (DPP) IV immunostaining was applied to 10 cases whose diagnoses had been corrected to follicular thyroid carcinoma because of distant metastases. The positive rate of immunostaining using paraffin sections in the rediagnosed follicular thyroid carcinoma group (7/10) was much higher than that of the control group (1/29), which consisted of 15 cases of follicular thyroid adenoma and 14 cases of nodular hyperplasia. These results suggested that pre- or postoperative DPP IV staining is useful for predicting distant metastasis of 'benign' thyroid tumor.

Adenocarcinoma, Follicular↗

PubMed1999

Macrophage populations and apoptotic cells in the liver before spontaneous hepatitis in Long-Evans Cinnamon (LEC) rats.

The inbred mutant strains of Long-Evans Cinnamon (LEC) rats spontaneously develops acute hepatitis as a result of abnormal copper accumulation, followed by chronic hepatitis, cholangiofibrosis and hepatocellular carcinoma. To shed some light on the role of macrophages in the liver failure, immunohistochemical methods were used to investigate the kinetics of macrophage populations in the liver of male LEC rats, in relation to the appearance of myofibroblastic cells and hepatocyte apoptosis. Rats examined at 24 weeks of age and moribund rats killed at 22-25 weeks of age had increased serum concentrations of aspartate aminotransferase and alanine aminotransferase, with jaundice and histological changes indicative of hepatic failure, whereas rats examined at 8, 12, 16 or 20 weeks old showed no such abnormal findings. Immunolabelling with ED1 (a monoclonal antibody recognizing rat macrophages) and ED2 (a monoclonal antibody specific for rat resident macrophages) revealed that numbers of blood monocyte-derived macrophages and Kupffer cells began to increase markedly at 16 weeks of age (before the onset of hepatitis). However, alpha-smooth muscle actin (SMA)-positive myofibroblastic cells (modulated perisinusoidal cells) and hepatocyte apoptosis, demonstrable by the TUNEL method, were rarely seen at 8, 12, 16, 20 or 24 weeks. There was no close relationship between macrophage expansion and the appearance of myofibroblastic cells or hepatocyte apoptosis. In moribund rats, only a few SMA-positive cells were seen in the periportal zones; hepatocytes undergoing apoptosis increased in number, and macrophages engulfing apoptotic bodies were observed occasionally, suggesting that apoptosis was related to hepatic failure as an early event. In addition, immunohistochemical examination demonstrated abnormal deposits of laminin along the sinusoids from 20 weeks, as an initial extracellular matrix protein in LEC rat livers.

Actins↗

PubMed1999

[Clinicobacteriological studies on the nine cases with upper genital tract Mycoplasma hominis infection].

Clinicobacteriological characteristics of nine cases isolated Mycoplasma hominis from the genital tract were studied, and the following results were obtained: elevation of IgG antibodies to M. hominis was measured by ELISA in all cases, but in the MI method only one case showed an elevation of metabolic inhibitory antibody. Convalescent sera from seven patients showed additional and high density bands which were not recognized by acute phase sera in immunoblotting. It was thought that in two patients M. hominis was a causal bacteria for pelvic inflammatory disease (PID). In three cases, it was suggested that M. hominis was related to a premature delivery and idiopathic labor. As infectious symptoms, two patients had body temperatures of more than 38 degrees C but other cases showed 37-37.8 degrees C. Though all cases showed an elevation of CRP, six elevations were slight. As a medication beta-lactam agents were administrated, but their efficacy was not recognized. Furthermore, two patients showed spontaneous recovery in spite of improper antimicrobial agents administration or drainage combined with antimicrobial agents. From the above results. It was thought that M. hominis played a causative role in upper genital tract infection.

Adult↗

PubMed1999

A novel mutation in the human thyroid peroxidase gene resulting in a total iodide organification defect.

In this study we describe a novel mutation of the thyroid peroxidase (TPO) gene that resulted in a total iodide organification defect. TPO activity and thyroxine formation in thyroglobulin in the thyroid gland of the patient were below the limits of detection. However, TPO mRNA was detectable at a similar size and concentration as compared with normal thyroid tissues when measured by Northern blot analysis. Sequence analysis of the TPO gene showed the presence of two mutations, a missense mutation in exon 7 and C insertion in exon 14. These mutations were heterozygous and located in different alleles. The latter mutation has already been reported as one of the mutations of the TPO gene resulting in total iodide organification defect. The former mutation was further analysed by mRNA transfection studies in which mutated mRNA was transfected to CHO-K1 cells by electroporation. The results of transfection studies showed that the cells transfected with mutated mRNA expressed similar size TPO molecules to those of cells transfected with wild-type mRNA but that they lacked TPO activity. The two mutations of the TPO gene resulting in the total iodide organification defect in the patient cosegregated from her parents.

Adenoma↗

PubMed1999

Nuclear proliferation in syncytia during avian reovirus replication.

Cultured chick embryonic fibroblasts formed syncytia after infection with avian reovirus (ARV) strain 58-132. Mitotic figures were occasionally observed within the syncytia. In addition, many nuclei in the syncytia incorporated 5-bromo-2'-deoxyuridine (BrdU), a DNA replication marker, indicating that they were in the S-phase of the cell cycle. These observations suggested that the nuclei within ARV-induced syncytia originated from nuclear endomitosis without cell division, as well as from cell fusion.

Animals↗

PubMed1998

Identification of highly conserved amino-terminal segments of dTAFII230 and yTAFII145 that are functionally interchangeable for inhibiting TBP-DNA interactions in vitro and in promoting yeast cell growth in vivo.

TFIID is a multiprotein complex composed of TBP and several TAFIIs. Small amino-terminal segments (TAF N-terminal domain (TAND)) of Drosophila TAFII230 (dTAFII230) and yeast TAFII145 (yTAFII145) bind strongly to TBP and inhibit TBP-DNA interactions. yTAFII145 TAND (yTAND) was divided into two subdomains, yTANDI10-37 and yTANDII46-71, that function cooperatively. Here, we identify dTANDII within the amino terminus of dTAFII230 at 118-143 amino acids in addition to dTANDI18-77, reported previously. dTANDII exhibits pronounced sequence similarity to yTANDII, and the two were shown to be functionally equivalent in binding to TBP and inhibiting TBP-DNA interactions in vitro. Alanine scanning mutation analysis demonstrated that Phe-57 (yTANDII) and Tyr-129 (dTANDII) are critically required for the interaction with TBP. Yeast strains containing mutant yTAFII145 lacking yTANDI or yTANDII showed a temperature-sensitive growth phenotype. The conserved core of dTANDII could substitute for the yTANDII core, and Phe-57 or Tyr-129 described above was critically required for the function of this segment in promoting normal cell growth at 37 degreesC. In these respects, the impact of yTANDII mutations on cell growth paralleled their effects on TBP binding in vitro, strongly suggesting that the yTAFII145-TBP interaction and its negative effects on TFIID binding to core promoters are physiologically important.

Amino Acid Sequence↗

PubMed1998

Histone-like TAFs within the PCAF histone acetylase complex.

PCAF histone acetylase plays a role in regulation of transcription, cell cycle progression, and differentiation. Here, we show that PCAF is found in a complex consisting of more than 20 distinct polypeptides. Strikingly, some polypeptides are identical to TBP-associated factors (TAFs), which are subunits of TFIID. Like TFIID, histone fold-containing factors are present within the PCAF complex. The histone H3- and H2B-like subunits within the PCAF complex are identical to those within TFIID, namely, hTAF(II)31 and hTAF(II)20/15, respectively. The PCAF complex has a novel histone H4-like subunit with similarity to hTAF(II)80 that interacts with the histone H3-like domain of hTAF(II)31. Moreover, the PCAF complex has a novel subunit with WD40 repeats having a similarity to hTAF(II)100.

Acetyltransferases↗

PubMed1998

Characterization of gastric Na+/I- symporter of the rat.

Characterization of gastric Na+/I- symporter (NIS) of the rat was carried out. Sequencing of the open reading frame of gastric NIS mRNA showed only three nucleotide changes when compared with FRTL-5 NIS cDNA, and two of these changes led to amino acid changes. The results of Northern blot analysis showed that abundant NIS mRNA was expressed in the stomach when compared with other organs. Western blot analysis using gastric mucosa and FRTL-5 lysates detected the difference in molecular weight between FRTL-5 and gastric mucosa lysates, suggesting abnormal posttranslational modification of gastric NIS protein. Immunohistochemically, gastric NIS protein was located in the cornification layer of the stratified squamous epithelium of the pars proventricularis and in parietal cells and on the apical border of surface epithelial cells of the pars glandularis. Gastric NIS protein was present in tubulovesicular structures and lysosomes in parietal cells by immunoelectron microscopy. Gastric NIS protein exists to trap I- from the gastric lumen, except in parietal cells. Results indicated that a very large amount of gastric NIS mRNA is expressed to be translated, whereas only a small amount of immature gastric NIS protein is detected. This may indicate that immature gastric NIS protein rapidly degrades to peptides.

Animals↗

PubMed1998

Analysis of aberrant neuronal migrations in the hereditary cerebellar vermis defect (CVD) rat using bromodeoxyuridine immunohistochemistry.

The hereditary cerebellar vermis defect rat (CVD) is a new neurological mutant characterized by cerebellar vermis defect and a dysplastic cerebellum, especially in the cerebello-pontine junctions. In this study, the cytokinetics of neuronal migrations in the CVD were analyzed using 5-bromo-2'-deoxyuridine (BrdU) as a labeling marker. From embryonic day 21, the CVD cerebellum was small in size with retarded foliation, but no significant differences were detected in the migration pattern of the BrdU-labeled cells between the unaffected controls and the CVD during the prenatal period. On postnatal day 0 (P0), heterotopic Purkinje cells, demonstrable by calbindin immunohistochemistry, were seen in the dorsal pons of the CVD. From P4, BrdU-positive external granule cells (EGCs), which were labeled by BrdU injection on P2, began to penetrate the pons. From P5, the EGCs aggregated around the blood vessels, leading to a disturbance of the cerebellar lamination both in the cerebello-pontine junctions and in the cerebellar hemispheres. Thereafter, the BrdU-labeled cells in the perivascularly aggregated EGCs migrated radially, and formed internal granular layers around the vessels, indicating an aberrant perivascular migration of the EGCs. These findings suggest that the EGC dislocation was preceded by an aberrant settlement of the Purkinje cells, and that the perivascularly aggregated EGCs resulted in cerebellar dysplasia in the CVD.

Aging↗