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Biomedical subjects

T Ohsawa

Publications and source records attributed to T Ohsawa.

At least 37 records · Page 2Linked to original sources
PubMed1999

Antibody reactivity in mice and cats to feline enteroepithelial stages of Toxoplasma gondii.

The reactivity of antibodies in mice and cats to feline enteroepithelial stages of Toxoplasma gondii was examined by means of an indirect immunofluorescent antibody test. Mice immunized with feline enteroepithelial stage (FES) parasites produced antibodies not only against FES, but also against tachyzoites, sporozoites/oocysts, tissue cysts and one part of the infected feline enterocytes. After absorption with tachyzoites, the titer of antibodies reactive to enterocytes was significantly reduced. In contrast, the titer of antibodies reactive to FES remained unchanged. The antibodies from cats immunized with FES, reacted specifically to FES, but not to tachyzoites, tissue cysts or enterocytes. These results suggest that FES parasites may have stage-specific antigen(s).

Animals↗
PubMed1999

Infectivity of feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation.

The infectivity of the feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation was examined by the trypan blue dye exclusion method by assaying their penetration into feline fibroblast cells in vitro and by inoculation of the intestinal mucosa of cats. A large population of the parasites showed trypan blue dye exclusion activity. When feline fibroblast cells were inoculated with feline enteroepithelial stage parasites, no intracellular parasites were found 18 h post-inoculation. Kittens inoculated intraduodenally with 2 x 10(6) feline enteroepithelial stage parasites shed oocysts between 2 and 8 days post-inoculation. These results indicate that the isolated feline enteroepithelial stage parasites display infectivity towards enterocytes of cats and are capable of gametogenesis.

Animals↗
PubMed1999

Collateral occurrence of deimination of keratins with differentiation of an immortalized newborn rat keratinocyte cell line cultured at air-liquid interface.

We devised a simple method to maintain an immortalized newborn rat keratinocyte cell line at the air-liquid interface using a tissue culture insert fitted with a microporous membrane. The cells formed stratified layers of flattened and anucleated cells resembling stratum corneum of the epidermis. Deiminated proteins, which are localized in the cornified layer of epidermis as the reaction products of peptidylarginine deiminase were detected immunohistochemically in the differentiated cells. Western blot analyses revealed that major deiminated proteins were type I keratins K10 and K14. Deiminated products of type II keratin K5 were found as minor components. Our observations show that deimination of keratins might be correlated with terminal differentiation of the immortalized keratinocyte cell line.

Animals↗
PubMed1998

Adenovirus-transferred HNF-3 gamma conserves some liver functions in primary cultured hepatocytes of adult rats.

Hepatocyte nuclear factor-3 (HNF-3) isoforms are key factors for regulation of gene expression and differentiation in hepatocytes. HNF-3gamma is abundantly expressed in the mature liver, but down-regulated in primary cultured hepatocytes, in which some other hepatic gene expressions are also decreased. In this study, the primary hepatocytes were infected with the recombinant adenovirus carrying HNF-3gamma gene (AxCAHNF3gamma), and this led to marked induction of the HNF-3gamma gene. As a result, the expressions of albumin, catalase, and ornithine transcarbamylase (OTC) genes were also recovered to significant levels in the AxCAHNF3gamma-infected hepatocytes. Moreover, hepatocyte proliferation stimulated by epidermal growth factor (EGF) and insulin was also inhibited by AxCAHNF3gamma infection. Our results demonstrate that the enforced expression of HNF-3gamma gene can lead to conservation of some original liver functions in the primary cultured hepatocytes accompanied by morphological differentiation and growth inhibition.

Adenoviridae↗
PubMed1998

X-ray absorption fine structure of V(2)O(5) and Li(x)V(2)O(5).

Vanadium K-edge XAFS measurements of five compounds were carried out. The compounds studied were crystalline V(2)O(5) and four types of Li(x)V(2)O(5) with different insertion levels x, which show different EMFs (2.0-3.4 V). The EXAFS data analysis shows no remarkable difference in the V-O distances in the five compounds, showing that the structure of the VO(5) square pyramids changes only slightly as lithium atoms are intercalated into the V(2)O(5). In the XANES spectra, three peaks are observed for crystalline V(2)O(5) and Li(x)V(2)O(5) (3.4 V). When the EMF is decreased, the intensity difference between the first and second peaks disappears and the third peak shifts to lower energy. The XANES data were analysed using full multiple-scattering calculations. In the calculated spectra the intensity of the first peak increases as the V(2)O(5) intercalates lithium atoms.

Journal Article↗
PubMed1998

Troglitazone, a new antidiabetic agent possessing radical scavenging ability, improved decreased skin blood flow in diabetic rats.

Troglitazone is a new class of antidiabetic agent possessing radical scavenging ability similar to vitamin E. Because of this ability, it is expected to improve decreased nutritive capillary blood flow in diabetes. In the present study, we investigated the effects of troglitazone on skin blood flow(SBF) in normal and streptozotocin(STZ)-induced diabetic rats. Effects of troglitazone on vasodilation, PGI2 and PGE2 production were also assessed in perfused hindlimb, isolated rat aorta rings and 3T6 fibroblasts, respectively. SBF at the base of the tail was decreased in STZ diabetic rats (2.1+/-0.2 ml/min/100 g) compared with normal rats (3.8+/-0.2 ml/min/100 g). This decrease of SBF was significantly improved (2.9+/-0.2 ml/min/100 g) by troglitazone treatment (approximately 220 mg/kg/day) for 7 days in STZ diabetic rats without alleviating hyperglycemia. Similar troglitazone treatment (approximately 160 mg/kg/day for 7 days) tended to increase SBF (approximately 30%) even in normal rats. In normal rats, subcutaneous administration of troglitazone (60 mg/kg) acutely increased SBF and, this increase was suppressed by 70% with pretreatment (10 mg/kg s.c.) of indomethacin, cyclooxygenase inhibitor, suggesting that troglitazone increases skin blood flow predominantly by increasing PGI2 and PGE2 production. In hindlimb perfusion under fixed flow rate, troglitazone infusion (20 microM) significantly decreased perfusion pressure by 13%, which reflects vasodilation of blood vessels. This decrease of perfusion pressure was inhibited by concomitant infusion of indomethacin but not N-monomethyl-L-arginine, inhibitor of nitric oxide synthase. In vitro studies, using isolated rat aorta rings, revealed that troglitazone (4.5 to 45 microM) increases PGI2 production by 31 and 70%, respectively. In 3T6 fibroblast (a component of skin tissue), troglitazone at a low dose of 0.3 microM increased PGI2 and PGE2 by 200% and 25%, respectively. Overall all, these results suggest that troglitazone increases nutritive SBF probably by virtue of its radical scavenging thus the resulting in an increase in PGI2 and PGE2 production in blood vessels and fibroblast. Troglitazone may alleviate impaired microcirculation in diabetic patients through these effects.

Animals↗
PubMed1996

All-trans retinoic acid increases peptidylarginine deiminases in a newborn rat keratinocyte cell line.

We studied the expression of peptidylarginine deiminases (EC 3.5.3.15) in an immortalized newborn rat keratinocyte cell line. No measurable enzyme activities were noted in either growing or confluent cultures. The enzyme activity was increased by all-trans retinoic acid in dose- and time-dependent manners. The enzyme activity was resolved into two peaks by anion exchange chromatography. The minor peak resembled enzyme preparations obtained from the epidermis in earlier studies. The major peak was indistinguishable from rat muscle peptidylarginine deiminase in the chromatographic and Western blotting profiles. Northern blot hybridization showed a major band in retinoic acid-treated cells migrating slightly behind muscle peptidylarginine deiminase mRNA.

Animals↗
PubMed1996

[A case of inflammatory pseudotumor of the lung with suppressed immune response in the patient with renal cell carcinoma after nephrectomy and administration of interferon].

A 60-year-old man with renal cell carcinoma was treated of right nephrectomy and high dose administration of Interferon-alpha (IFN) in 1990. Three and half years after operation, he complained of cough and hemoptysis. Chest X-ray showed a abnormal shadow (5.5 x 3.5 cm) in the upper lung field. On chest CT, a tumor mass with small cavity was located at S2, attended with the speculation and pleural indentation. A rough nodule suspected daughter tumor was pointed out near the tumor mass. Laboratory investigation revealed mild leucocytosis, an elevated ESR and C reactive protein. On lymphocyte subset, CD 4/8 ratio was 0.8 and NK cell activity was 11%. Immunosuppressive acid protein (IAP) in serum was 1,137 ng/ml. No organisms or malignant cells could be demonstrated in the biopsy materials or sputum. Right thoracotomy and upper lobectomy was carried out. Postoperative pathological diagnosis was inflammatory pseudotumor. Namely, the lesion was occupied with variable admixture of lymphocytes, plasma cells, histiocytes, phagocytes included hemosiderin, foam cells and whorled fibrosis. Daughter tumor was scar tissue. Now, he is well without recurrence and his immune response is within normal level. Some discussion of the literature was mentioned.

Autoimmune Diseases↗
PubMed1995

[A successfully treated case of thoracoabdominal aortic aneurysm complicated with the coagulation disorder].

We could performed the safe operation for thoracoabdominal aortic aneurysm complicated with pre-DIC. A diagnosis of pre-DIC was made by laboratory data. Low heparin pretreatment was performed for the short term because we presumed the cause for pre-DIC was thromboses in aneurysm. That treatment was effective for the temporal remission of pre-DIC. In addition, during partial ECC low heparin (1 mg/kg) and nafamostat mesilate (2 mg/kg/h) were used. As a result, during and after the operation blood loss was a little. In summary heparin pretreatment is useful therapy for DIC and pre-DIC in aortic aneurysm patients.

Aged↗
PubMed1995

Experimental infection of juvenile Biomphalaria glabrata with cercariae of Echinostoma trivolvis.

Infectivity studies were done on laboratory-reared Biomphalaria glabrata juvenile (neonatal) snails exposed to cercariae of Echinostoma trivolvis. Of the 40 snails, 0.7-1.0 mm in shell diameter, which were exposed to a total of 1,000 cercariae for 24 hr, all were infected with 1-29 viable encysted metacercariae per snail. Biomphalaria glabrata, 1-2 mm in shell diameter, were used to determine the effects of an infectious dose of 25 cercariae/juvenile on subsequent snail survival. The median survival time of 24 exposed snails occurred between day 3 and 4 postinfection, at which time more than 90% of 24 control (unexposed) snails were alive. The high mortality in the E. trivolvis-infected B. glabrata juveniles was probably related to cercarial penetration and encystment in the snail tissue, although histological examination of snails after exposure would be required to determine the actual cause of the observed mortality.

Animals↗
PubMed1994

Carpal tunnel syndrome: evaluation of median nerve circulation with dynamic contrast-enhanced MR imaging.

PURPOSE: To identify mechanism(s) responsible for carpal tunnel syndrome (CTS). MATERIALS AND METHODS: At dynamic gadolinium-enhanced magnetic resonance (MR) imaging, the enhancement pattern of the sagittal section of the median nerve in 10 wrists of nine patients with CTS (two men and seven women, aged 43-60 years [mean, 52 years 10 months]) was studied while each wrist was in a neutral, flexed, and/or extended position. Five asymptomatic volunteers (four men and one woman, aged 23-54 years [mean, 31 years 5 months]) also underwent MR imaging to establish the normal enhancement patterns. RESULTS: Two distinctly abnormal patterns of median-nerve enhancement were revealed: marked or no enhancement. Marked enhancement was attributed to nerve edema, and the lack of enhancement was attributed to ischemia. Marked enhancement changed to no enhancement changed to no enhancement when the wrists were in a flexed or extended position. This change was associated with an aggravation of the symptoms of CTS. CONCLUSIONS: CTS may result from a circulatory disturbance rather than from deformation or compression of the nerve.

Adult↗
PubMed1994

Triangular fibrocartilage in asymptomatic subjects: investigation of abnormal MR signal intensity.

PURPOSE: To investigate the prevalence of abnormally high signal intensity of triangular fibrocartilage (TFC) tears on magnetic resonance (MR) images of asymptomatic subjects. MATERIALS AND METHODS: MR images of one wrist in 70 asymptomatic volunteers (age range, 15-78 years) were evaluated for TFC high signal intensity. Findings at MR imaging and topographic parameters of each wrist studied were correlated with the subject's age. Any vertical or horizontal high-intensity slits that reached the joint surface or evidence of a perforation was considered abnormal. RESULTS: Abnormally high TFC signal intensity was seen on images of 35 (50%) wrists. Further, a thin TFC was more often seen in subjects with positive variance, and positive ulnar variance and thin TFC were associated with high signal intensity. Age did not substantially affect the presence or absence of high signal intensity. CONCLUSION: Since TFC high signal intensity was frequently detected in these asymptomatic wrists, MR imaging cannot reliably be used to detect clinically meaningful abnormalities.

Adolescent↗
PubMed1994

Focal obliteration of the descending aortic interface on normal frontal chest radiographs: correlation with CT findings.

PURPOSE: To assess the frequency, location, correlation with age, and cause of partial obliteration of the descending aortic interface on normal frontal chest radiographs. MATERIALS AND METHODS: Concurrent chest radiographs and computed tomographic (CT) scans of 1,500 patients in whom CT findings excluded a diagnosis of paraaortic pathologic processes were reviewed retrospectively. RESULTS: Aortic interface obliteration was identified on 134 images (8.9%), which included 43 (2.9%) in the suprahilar and upper hilar portion, 56 (3.7%) in the lower hilar portion, and 46 (3.1%) in the cardiac portion of the interface. The causes were direct contact with or proximity to the aortic margin by pulmonary arteries at the suprahilar and upper hilar portion, superior segment vessels at the lower hilar portion, and various structures, including left inferior pulmonary vein, mediastinal fat, and left ventricle at the cardiac portion. CONCLUSION: Partial aortic interface obliteration can be seen on normal frontal chest radiographs because of obstruction by small adjacent structures.

Adolescent↗
PubMed1994

Ulnar collateral ligament in the growing elbow: MR imaging of normal development and throwing injuries.

PURPOSE: To study the magnetic resonance (MR) imaging appearance of the ulnar collateral ligament (UCL) and its insertion into the medial epicondyle. MATERIALS AND METHODS: Sixteen normal and 20 symptomatic elbows were examined with a 1.5-T unit. Normal elbows were imaged with axial T2*-weighted three-dimensional Fourier transform sequences. Symptomatic elbows were imaged with coronal T1-, T2-, and T2*-weighted and/or short-inversion-time inversion-recovery sequences. RESULTS: In normal immature elbows, the ulnar periosteum was seen as an extension of the UCL, and its enthesis had signal intensity characteristics that differed from those of the mature ligament. In symptomatic elbows imaged before epiphyseal fusion, segmentation and subchondral bone resorption of the ossification center were seen with or without a capsular tear. After epiphyseal fusion, a full-thickness or a partial UCL tear at the site of its insertion, with or without subcortical bone resorption, was seen. CONCLUSION: The MR imaging characteristics of the developing elbow differ from those of the mature elbow. MR imaging is useful in assessing UCL damage.

Adolescent↗
PubMed1994

Unilateral hyperlucent thorax on plain chest radiographs after neck dissection: importance of atrophy of the trapezius muscle.

OBJECTIVE: A hyperlucent thorax on plain chest radiography indicates a decrease in the radiographic density of the thorax, which can be caused by intra- or extrapulmonary diseases. The purpose of this study was to assess the prevalence and mechanisms that may be responsible for unilateral hyperlucency of the thorax after neck dissection and to determine if atrophy of the trapezius due to the transection of the accessory nerve is a cause of hyperlucent thorax. MATERIALS AND METHODS: Differences in the radiographic density between the right and left lung were evaluated and correlated with transection of the accessory nerve in 21 patients who had had a radical or a modified neck dissection for a malignant tumor of the head and neck. Twenty-eight neck dissections were performed on these 21 patients (seven had a simultaneous bilateral neck dissection). In 14 of the 21 patients, the accessory nerve had been severed during the neck surgery. In six patients, mechanisms responsible for a hyperlucent thorax were investigated with follow-up thoracic CT scans. RESULTS: In the radiographs, eight patients had a hyperlucent thorax on the side of the neck dissection. In all of these cases, the accessory nerve on the side of this neck dissection had been severed during a radical or a modified neck dissection. Prior to surgery, no such hyperlucency was noted. CT scans showed atrophy of the denervated trapezius muscle. CONCLUSION: Our findings show that atrophy of the denervated trapezius muscle after neck dissection is a cause of unilateral hyperlucent thorax on plain chest radiographs. Therefore, this finding should be anticipated as a postoperative change in patients who have had this surgery.

Accessory Nerve↗