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Biomedical subjects

Y Terada

Publications and source records attributed to Y Terada.

At least 217 records · Page 12Linked to original sources
PubMed1995

Presence and regulation of Raf-1-K (Kinase), MAPK-K, MAP-K, and S6-K in rat nephron segments.

Renal nephron segments are heterogeneous, and receptors for endothelin (ET)-1, ET-3, Angiotensin II (AII), epidermal growth factor (EGF), and insulin-like growth factor I distribute differently along the nephron segments. Recently, growth factors and vasoactive substances are reported to stimulate mitogen-activated protein kinase (MAP-K). In this study, we showed that mRNA and proteins of MEK-K, Raf-1-K, MAPK-K, MAP-K (p42 and p44), and S6-K are expressed ubiquitously in intact nephron segment. We demonstrated that four tiers of a cascade composed of the Raf-1-K, MAP-K, MAP-K, and S6-K are stimulated by ET-1 and ET-3 in rat intact glomeruli (Glm) via primarily B-type ET receptors and PKC. The stimulatory effect of EGF and IGF-I to MAP-K activity is inhibited by a tyrosine kinase inhibitor in Glm. IGF-I significantly stimulates MAP-K activity and EGF and All moderately stimulate MAP-K activity in the proximal convoluted tubule (PCT). EGF significantly increased MAP-K cascades and ET-1 and ET-3 slightly increased MAP-K cascades in the medullary thick ascending limb (MTAL). EGF significantly stimulated MAP-K cascades, and ET-1 and ET-3 moderately stimulate MAP-K cascades in the outer medullary collecting duct (OMCD) and the inner medullary collecting duct (IMCD). MAPK-K and S6-K are similarly stimulated by these agonists in each segment. This study shows that MAP-K cascades are expressed in every nephron segment. ET-1, ET-3, All, EGF, and IGF-I stimulate MAP-K cascades heterogeneously along the nephron segment. It was concluded that MAP-K cascades play an important role in the regulation of renal function.

Animals↗
PubMed1995

[Histopathological analysis of herniated cerebellar tonsils resected from the patients with Chiari type I malformation with syringomyelia].

Cerebellar tonsillectomy is a controversial treatment for Chiari type I malformation combined with syringomyelia. To demonstrate the validity of this procedure, we evaluated the postoperative clinical course, the histopathological finding in the resected cerebellar tonsils and the MR images of four patients. The patients were all women, ranging in age from 27 to 58 years old (mean: 43 years). The postoperative follows-up period lasted from 28 to 51 months (average: 38 mos), and the neurological symptoms and signs improved in all patients. Histopathological examination of the resected tonsils revealed a loss of Purkinje cells and granule cells. Vacuolated degeneration and chromatolysis were also seen, and modified Bielschowsky stain revealed axonal degeneration. These findings appeared to be irreversible. Postoperative T1-weighted MR images of the cervical and thoracic spine demonstrated a decrease in the size of the syrinx and the disappearance of evidence of tonsillar herniation in all patients. Postoperative phase-contrast MR images showed good CSF pulsation in the subarachnoid space at the craniocervical junction in all three patients examined. It was possible to avoid surgical complications by using careful microsurgical techniques. Based on these results, we concluded that cerebellar tonsillectomy is an adequate surgical strategies for treating Chiari type I malformation associated with syringomyelia.

Adult↗
PubMed1995

[Citrate and ionized calcium on extracorporeal circulation in pediatric cardiac surgery].

The control of optimum concentrations of ionized calcium Ca2+ during cardiopulmonary bypass is important in maintaining cardiac function and reducing reperfusion injury. Ca2+ may be in part dependent upon the serum level of citrate Cit in use of hemodiluted prime in pediatric cardiac surgery. The purpose of this study was to ascertain fluctuations of Ca2+ during bypass in relation to Cit and to study control of optimum Ca2+. Ca2+ and Cit was measured prior to and every 10 or 20 minutes during bypass in 12 children aged 21 days to 6 years. Of 6 patients (body weight less than 6 kg) received acid-citrate-dextrose (ACD) solution 20 ml before aortic declamp to give low Ca2+ for reducing reperfusion injury. Ca2+ showed initial drop and then gradually increased as the result of decreasing Cit. Ca2+ was inversely correlated with Cit (r = 0.85, p = 0.0001). When ACD 20 ml was added, Ca2+ significantly decreased from 1.00 +/- 0.13 to 0.65 +/- 0.13 mmol/l. However, Cit remained 24.3 +/- 13.3 mg/dl at the end of bypass. In conclusion, the results of this study suggest that gradually increasing Ca2+ during bypass may be related to the rate of citrate metabolism and the use of citrate for the control of Ca2+ remains questionable.

Calcium↗
PubMed1995

[Postoperative bronchial stenosis associated with IAA complex and transendoscopic resection of intrabronchial granulation].

Problem with stenosis of the left bronchus was encountered in a patient with type B interrupted aortic arch complex after the arch reconstruction and pulmonary artery banding. Bronchoscopic study disclosed the intraluminal granulation of left bronchus and transendoscopic resection of the granulation successfully relieved the stenosis and brought the patient to full recovery.

Airway Obstruction↗
PubMed1995

[Application of large curved forceps for taping in cardiovascular surgery].

A new large curved forceps was manufactured for trial with the object of taping in cardiovascular surgery. Widely used and commercially available forceps could be utilized on the taping of large vessel less than 5 to 5.8 cm in diameter. With this new forceps, aneurysmally dilate great vessels (less than 8 cm in diameter) could be safely taped without compression of aortic wall. This forceps has already applied not only for the major vascular surgery, but also for the wearing of cardiac net in coronary artery bypass grafting.

Aortic Aneurysm↗
PubMed1994

Sequential activation of Raf-1 kinase, mitogen-activated protein (MAP) kinase kinase, MAP kinase, and S6 kinase by hyperosmolality in renal cells.

In the renal medulla during antidiuresis, the extracellular fluid becomes hyperosmotic. Madin-Darby canine kidney (MDCK) epithelial cells adapt in hyperosmotic conditions and serve as a useful tissue culture model for cellular responses to hyperosmolality. We demonstrate that hyperosmolality stimulates phospholipase C, Raf-1 kinase mitogen-activated protein (MAP) kinase kinase, MAP kinase, and S6 kinase activities and that it increases phosphorylation of Raf-1 kinase, and p42 MAP kinase in MDCK cells. Stimulation of these kinases is osmolality-dependent (from 300 to 600 mosm/kg H2O). The time course of activation is sequential; the peak stimulation for Raf-1 kinase is at 5 min, at 10 min for MAP kinase kinase and MAP kinase, and at 20 min for S6 kinase. The activation of Raf-1 kinase and MAP kinase is inhibited by phorbol 12-myristate 13-acetate pretreatment in the presence of calphostin C or H-7. Tyrosine kinase inhibitors (genistein, herbimycin) do not significantly suppress hyperosmolality-induced MAP kinase activity. The increase of Ins-1,4,5-P3 levels by hyperosmolality suggests that activation of these kinases is mediated at least partially via activation of phospholipase C. Thus, hyperosmolality stimulates the serine/threonine kinases, Raf-1 kinase, MAP kinase kinase, MAP kinase, and S6 kinase, via predominantly protein kinase C-dependent, tyrosine kinase-independent pathways in MDCK cells.

Amino Acid Sequence↗
PubMed1994

Rapidly deteriorated failure of Carpentier-Edwards porcine bioprosthesis caused by three detached commissures: report of a case.

A 58-year-old man required an emergency redo mitral valve replacement due to a rapidly deteriorating failure of the Carpentier-Edwards porcine bioprosthesis within [corrected] a few days after the initial operation. The removed bioprosthesis showed that its three commissures had all peeled off each stent, which may have occurred within a short time, and caused massive, rapidly progressive trans-bioprosthetic regurgitation.

Bioprosthesis↗
PubMed1994

Clinical effects of long-term administration of pimobendan in patients with moderate congestive heart failure.

The long-term efficacy of the positive inotropic and vasodilator drug, pimobendan, was assessed in 21 patients suffering from symptomatic heart failure. Patients were randomized to 16 weeks of double-blind therapy with either 2.5 or 5.0 mg/day of pimobendan (n = 10), or a matching placebo (n = 11). Patients were blinded on the study drug if their clinical status had not substantially worsened during the study. Of the placebo-treated patients, 5 patients were withdrawn from the study because of a deterioration of their heart failure, while none of the active treated group was withdrawn because of increased symptoms. Quality of life, assessed by the specific activity scale derived from the metabolic costs of individual physical activity, was 3.45 +/- 0.90 (SD) mets in the baseline state and increased significantly after week 16, averaging 5.07 +/- 1.40 and 4.67 +/- 1.47 mets at weeks 16 and 24, respectively. In the placebo-treated group, the specific activity scale was 3.27 +/- 1.21 mets at the baseline and remained unchanged throughout the study period. Patients treated with pimobendan were able to significantly increase their exercise duration. The accompanying increase in peak oxygen uptake was statistically insignificant, due to the limited number of patients enrolled in the study. These results suggest that in contrast to the recent pessimistic view of the long-term efficacy of cardiotonic drugs, pimobendan is beneficial in treating patients with congestive heart failure and may favorably modify their prognosis. Further large-scale evaluation of this agent is warranted.

Activities of Daily Living↗
PubMed1994

Seroprevalence of leptospirosis in a rural flood prone district of Bangladesh.

Leptospirosis is a worldwide zoonotic disease. In the present investigation, a total of 89 human sera from a flood prone district of Bangladesh was screened by a one-point microscapsule agglutination test (MCAT). MCAT-positive and -doubtful sera were further tested by microscopic agglutination test (MAT) against 16 reference serovars of Leptospira interrogans, and the antibody titres determined. In MCAT, 34 sera were positive and 22 were doubtful. Among those positive and doubtful sera, 33 and 20, respectively were tested by MAT. Thirty-four out of 53 MCAT-screened samples were MAT-positive. The titres ranged from 20 to 1600 with antibodies to serovars copenhageni, australis, cynopteri and icterohaemorrhagiae being the most prevalent. Eleven MCAT-positive samples failed to react with any strains used by MAT, suggesting the presence of new or untested serovars. Among the MAT-positive samples, the presence of antibody against two or more serovars was more common than that of a single serovar. The present study suggests that rural people in Bangladesh are at high risk to leptospiral infection.

Agglutination Tests↗
PubMed1994

Localization of cyclophilin A and cyclophilin C mRNA in murine kidney using RT-PCR.

Cyclosporin A (CsA), which is widely used as an immunosuppressant, has a nephrotoxic side effect. The mechanism of this nephrotoxicity is not well understood; however, recent studies suggest that cyclophilin (cyp) is responsible for mediating the immunosuppressive action of CsA through the interaction with the Ca(2+)- and calmodulin-dependent phosphatase, calcineurin. While cyp A mRNA is expressed ubiquitously, cyp C mRNA has been shown to be topically expressed, including in the kidney. We examined: (1) distribution of cyp A and cyp C mRNA in microdissected murine nephron segments, using a combination of reverse transcription and polymerase chain reaction (RT-PCR) techniques, and (2) the effect of CsA administration on cyp C mRNA expression in proximal convoluted tubule. Among the nephron segments examined, large signals for cyp C PCR product were detected in proximal convoluted tubule and proximal straight tubule. Our data showed that the distribution of cyp C mRNA was uneven, and it mainly existed in segments that are relatively sensitive to CsA toxicity. In contrast, cyp A mRNA was found to be distributed almost equally along the nephron segments examined. By CsA administration, the signal for cyp C mRNA PCR product was increased. These results suggest that cyp C may play some role in the renal tubular disorder observed in CsA nephrotoxicity.

Amino Acid Isomerases↗
PubMed1994

Effects of hyperosmolality on ANP-stimulated cGMP generation in rat inner medullary collecting duct.

The inner medullary collecting duct (IMCD) is a major target site of atrial natriuretic peptide (ANP) for diuresis and natriuresis, and it is in a hypertonic condition made by the renal countercurrent multiplication system. We investigated the effects of hyperosmolality on ANP-stimulated cGMP generation in IMCD and glomerulus. Hypertonic solutions (490 and 690 mOsm/kg.H2O) were made by adding NaCl or urea to isotonic solution (290 mOsm/kg.H2O). Hypertonicity of 490 mOsm/kg.H2O using NaCl reduced both ANP-stimulated guanylate cyclase activity (from 7.7 +/- 1.1 to 4.1 +/- 0.5 fmol/mm/5 min) and cGMP generation (from 1.35 +/- 0.18 to 0.48 +/- 0.20 fmol/mm/3 min) in IMCD. Hypertonicity of 690 mOsm/kg.H2O using NaCl did not further reduce ANP-stimulated cGMP generation in IMCD. Hypertonicity using urea also inhibited ANP-stimulated guanylate cyclase activity and cGMP generation in IMCD. On the other hand, hypertonicity using NaCl stimulated AVP-stimulated cAMP generation in IMCD, while hypertonicity using urea reduced it. In glomeruli, hyperosmolality of 490 mOsm/kg.H2O using NaCl also reduced ANP-stimulated cGMP generation, and hypertonicity of 690 mOsm/kg.H2O using NaCl further reduced it. In summary, hyperosmolality using NaCl and urea inhibited ANP-sensitive guanylate cyclase activity and cGMP generation both in IMCD and glomeruli. However, the mechanisms at work may be different between NaCl and urea.

Animals↗