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Biomedical subjects

T Koyanagi

Publications and source records attributed to T Koyanagi.

At least 19 recordsLinked to original sources
PubMed1999

Different expressions of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid and N-methyl-D-aspartate receptor subunit mRNAs between visceromotor and somatomotor neurons of the rat lumbosacral spinal cord.

The glutamatergic transmission system plays a key role in afferent and efferent pathways involved in micturition. By in situ hybridization combined with retrograde Fast Blue labeling, expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor (GluR-A to -D) and N-methyl-D-aspartate (NMDA) receptor (NR1 and NR2A-D) subunit mRNAs were examined in visceromotor and somatomotor neurons of the rat lumbosacral spinal cord. Parasympathetic preganglionic neurons (PGNs) in the intermediolateral nucleus highly expressed GluR-A and GluR-B subunit mRNAs, with very low levels for GluR-C and GluR-D subunits. As for the NMDA receptor, PGNs were associated with abundant signals for NR1 subunit mRNA, but without any NR2 subunit mRNAs. On the other hand, somatomotor neurons in the ventral horn (dorsolateral nucleus) express all four AMPA receptor subunit mRNAs, showing relatively abundant expressions of GluR-C and GluR-D subunit mRNA compared with PGNs. In addition to high levels of NR1 subunit mRNA, dorsolateral nucleus neurons moderately expressed NR2A and NR2B subunit mRNAs. These results suggest that molecular organization of both AMPA and NMDA receptor channels are distinct between PGNs and dorsolateral nucleus neurons. Considering that native NMDA receptors are heteromeric channels composed of NR1 and NR2 subunits, it seems likely that dorsolateral nucleus neurons, not PGNs, are provided with functional NMDA receptors, which could induce activity-dependent changes in synaptic transmission in the efferent pathway for the lower urinary tract.

Amidines↗
PubMed1999

Thoracic and cardiovascular interventions after orthotopic heart transplantation.

BACKGROUND: The long-term outcome of orthotopic heart transplantation is limited by the development of cardiac allograft vasculopathy, rejection, infection, and malignancy. METHODS: After heart transplantation, we treated patients with thoracic and cardiovascular diseases: preexisting coronary artery sclerosis in 2 patients, cardiac allograft vasculopathy in 19, valvular disease in 3, mycotic ascending aortic aneurysm in 2, superior vena cava stenosis in 2, and lung neoplasm in 10 patients. RESULTS: We successfully performed coronary artery bypass grafting for preexisting coronary artery sclerosis, valve replacement for valvular disease, and patch enlargement for superior vena cava stenosis. Percutaneous transluminal coronary angioplasty for cardiac allograft vasculopathy achieved excellent initial results, but the incidence of restenosis was high (67%). One patient who underwent coronary artery bypass grafting for cardiac allograft vasculopathy died immediately after operation. Graft replacement was performed for mycotic aortic aneurysm, but 1 patient required reoperation because of recurrent aneurysm. The long-term survival rate in patients undergoing surgical resection for lung neoplasm was poor (50%). CONCLUSIONS: The need for thoracic and cardiovascular interventions in patients after heart transplantation was low (4.7%). Use of the appropriate procedures can improve the long-term survival after heart transplantation.

Adolescent↗
PubMed1999

The relevance of urethral resistance in children with myelodysplasia: its impact on upper urinary tract deterioration and the outcome of conservative management.

PURPOSE: Upper urinary tract deterioration, such as vesicoureteral reflux and hydronephrosis, affects the long-term prognosis in children with myelodysplasia. We retrospectively analyzed the relevance of urethral resistance to upper tract deterioration in untreated children with myelodysplasia as well as the outcome of conservative treatment based on urethral resistance. MATERIALS AND METHODS: Included in our study were 32 boys and 29 girls with a mean age at presentation of 3.6 years and a mean followup of 9.2 years. The children were divided into group 1-31 with high and group 2-30 with low urethral resistance, as determined by leak point pressure or maximum urethral closing pressure. Clean intermittent catheterization with or without anticholinergics was instituted in all children in group 1 and those in group 2 with documented upper tract deterioration and/or problematic urinary incontinence after school age. We compared the incidence of upper tract deterioration at the initial evaluation and during followup as well as the final status of the upper tract in the 2 groups. RESULTS: At the initial evaluation 17 of 31 group 1 (55%) and 4 of 30 group 2 (13%) patients had upper tract deterioration (p <0.01). Deterioration was refractory to conservative management in 5 group 1 children who required bladder augmentation. The incidence of de novo upper tract deterioration during followup was not statistically different in the 2 groups (10 and 7% in groups 1 and 2, respectively). At the final evaluation the upper tract was normal in 26 (84%), improved in 3 and stable in 2 group 1 patients, while it was normal in 26 (87%) in group 2. CONCLUSIONS: Urethral resistance is relevant to upper tract deterioration in untreated children with myelodysplasia. Although bladder augmentation was necessary in some children with high urethral resistance, the outcome of conservative treatment was generally satisfactory with the preservation or normalization of the upper tract in more than 80% regardless of urethral resistance.

Adolescent↗
PubMed1999

Rhythmic changes in the stomach movement of the human fetus with congenital duodenal obstruction during the third trimester of pregnancy.

In order to reveal whether or not rhythmic changes exist in fetal stomach movement (FSM), in utero FSM was assessed in three fetuses between 27 and 33 weeks' gestation with congenital duodenal obstruction. A total of four observations, one each at 27, 29, 31 and 33 weeks' gestation, was obtained. The longitudinal transection of each fetal stomach was continuously observed for 60 min using real-time ultrasound. The configuration and the area of the stomach were analyzed for each 15-s epoch. The complexity of the stomach configuration was quantified and defined as stomach complexity. For each case, the chronological changes of the stomach complexity were analyzed using the least median square of regression. The correlation between changes of the stomach complexity and the area of the stomach was analyzed using the cross-correlation method. (1) For gestational ages of 27, 29, 31 and 33 weeks, the 240 sequential measurements of the stomach complexity were significantly stratified into outlying and non-outlying points. The outlying points were 13.3% (32/240), 30.8% (74/240), 32.9% (79/240) and 36.3% (87/240) of the total observation points, respectively. (2) The percentages in which outlying points lasted 3 min (12 points) or more were 0% (0/240), 5.0% (12/240), 28.3% (68/240) and 30.4% (73/240) of the total observation points, respectively. (3) For each gestational age, no significant time series correlation was found between the stomach complexity and the area of the stomach. These findings suggest that: (1) two different conditions emerge in the FSM, at the latest at 27 weeks' gestation, and begin manifesting from 29 weeks' gestation onwards. (2) These chronological changes cluster into 'active' and 'quiet' phases from 31 weeks' gestation onwards. (3) FSMs are not related to the changes in the stomach area throughout the observation periods. The underlying mechanism of this rhythmicity may represent the development of ultradian rhythm of the stomach movement, generated by the central nervous system.

Duodenal Obstruction↗
PubMed1999

Changes in renal blood flow in response to sympathomimetics in the rat transplanted and denervated kidney.

BACKGROUND: Renal denervation and re-innervation may affect vascular responses to sympathomimetics, which may play a role in the maintainance of renal blood flow (RBF) following renal transplantation. The purpose of the present study was to elucidate pharmacological alteration of the renal sympathetic response following kidney transplantation. Using the rat kidney transplantation model, we focused on responses to various sympathomimetics in order to investigate the effects of sympathetic denervation and functional remodulation mechanisms in the transplanted kidney. METHODS: Male isogenic rats underwent unilateral kidney denervation or kidney transplantation accompanied by unilateral native nephrectomy. Renal blood flow was evaluated using a laser Doppler flow meter following bolus injection of 50 microg/kg dopamine and continuous infusion of 60 microg/min phenylephrine (PE) at 0, 30, 60, 90 and 240 days after transplantation as well as at 30 days after denervation. RESULTS: Bolus injection of dopamine (50 microg/kg) induced an initial reduction in RBF (that of alpha-adrenoceptors) followed by a long-lasting increase in RBF (that of beta-adrenoceptors) in the native kidney. In grafted or denervated kidneys, the dopamine-induced decrease in RBF mediated by alpha-adrenoceptors was markedly enhanced while the increase in RBF mediated by an action of dopamine on beta-adrenoceptors was blunted. The effects of the post-transplant period on vascular responses to dopamine were significant, but not completely synchronized with the native kidney, even at 240 days. Continuous infusion of PE (60 microg/min) produced a gradual increase in RBF in the native kidney, whereas a sudden reduction (i.e. breakthrough in autoregulation) was observed in the denervated and transplanted kidney. CONCLUSIONS: The responses to sympathomimetics in the grafted kidney were shifted towards flow reduction (i.e. enhanced vasoconstriction via stimulation of alpha-adrenoceptors and blunted vasodilatation via stimulation of beta-adrenoceptors. This functional impairment was recovered in a time-dependent manner. In addition, the hemodynamic autoregulation system in the kidney deteriorated following transplantation or denervation.

Animals↗
PubMed1999

Impact of congenital narrowing of the bulbar urethra (Cobb's collar) and its transurethral incision in children.

OBJECTIVES: We described the clinical manifestation and outcome after transurethral incision (TUI) of a congenital narrowing of the bulbar urethra (Cobb's collar). MATERIALS AND METHODS: Over a period of 11 years a total of 74 boys, from 3 months to 16 years old with a mean age of 5 years, were subjected to TUI. A febrile urinary tract infection (UTI) was the most common symptom in 40 cases, enuresis in 15, urinary incontinence in 11, hematuria in 9, antenatally diagnosed dilated urinary tract in 4 and others in 9. Concurrent bladder instability was detected by cystometry in 27/31 boys older than 3 years with suspicious bladder urgency. When the bulbar narrowing was detected by cystourethroscopy under 8 Fr, the lesion was simultaneously incised by using an infantile resectoscope (Olympus 10 Fr with a knife electrode or Storz 10 F with a cold knife). RESULTS: Vesicoureteral refluxes (VURs) occurred in 39 cases (53%) and it was diminished in 11 and improved in 25 after TUI. Of the 40 cases, 38 (95%) were free from UTI after TUI. For enuresis and urinary incontinence, 14/15 and all 11, respectively, thrived after TUI and the anticholinergic supplement. Although 61 cases were primarily cured with no complications, insufficient cutting and recurrence of the stricture required an additional TUI in 13 cases for whom the knife electrode was mostly used. Overall clinical improvement was obtained in 71/74 (93%) cases after TUI. CONCLUSION: Meticulous cystourethroscopy is indispensable for detecting a clinically significant bulbar narrowing. TUI of the lesion is useful as a primary treatment in the majority of cases even with concurrent VUR and unstable bladder. A cold knife is preferable to electrocautery in incising this fine anterior urethral lesion.

Adolescent↗
PubMed1999

Synthesis and antitumor activities of water-soluble benzoylphenylureas.

Water-soluble benzoylphenylurea derivatives were synthesized as candidate prodrugs and their antitumor activities were examined in vivo against P388 leukemia. Some of the prodrugs were highly soluble in water and showed good antitumor activities against P388 leukemia cells in mice when injected intravenously.

Animals↗
PubMed1999

[Assessment of QOL and survival for patients undergoing radical cystectomy or bladder preservation for invasive bladder cancer].

PURPOSE: In this study, we have retrospectively compared patient backgrounds, prognosis and QOL (quality of life) in patients with invasive bladder cancer treated by radical cystectomy or by bladder preservation. PATIENTS AND METHODS: This study enrolled recent 30 cases from each institutions, totally 120 cases from four institutions. All patients were diagnosed with invasive bladder cancer in stage T 2 or T 3, N 0, M 0. The patients planned for preserving the bladder were treated with a combination of intra-arterial chemotherapy and radiation as an induction therapy. The questionnaire used to assess QOL was the EORTC QLQ-C 30 (Japanese-language edition). RESULTS: Radical cystectomy was selected as the initial treatment in 60 cases (the planned radical cystectomy group). Bladder preservation was planned but the presence of residual tumors after induction therapy underwent radical cystectomy in 18 cases (the preservation-radical cystectomy group). Bladder preservation was achieved in 42 cases (the preservation group). In a comparison of background factors, histologically grade 3 tumor and cases with histology other than transitional cell carcinoma, were significantly common in the planned radical cystectomy group. Because this study is not an randomized test, it is difficult to compare the outcomes between the patients treated by radical cystectomy or by bladder preservation. However, it is indicated that the candidates for bladder preservation therapy exist among the patients with T 2 or T 3, N 0, M 0 bladder cancer. Quality of life, as evaluated from global QL and from physical, cognitive, and emotional function, tended to be better in the patients with their bladder, although no difference was noted among the groups with regard to life role or social function. Symptoms such as sleep disturbance and diarrhea were common in the radical cystectomy groups, and financial impact, constipation, appetite loss, and dyspnea also tended to more frequently affect patients in these groups. CONCLUSION: Our results indicate that bladder preservation treatment using an induction therapy is one of option of the treatment for clinically T 2 or T 3, N 0, M 0 bladder cancer. We need a prospective randomized study with a long-term follow-up to elucidate true candidates for this treatment.

Aged↗
PubMed1999

Reduction of integrin beta4 and enhanced migration on laminin in association with intraepithelial spreading of urinary bladder carcinomas.

PURPOSE: The aim of the present study was to investigate the biological and molecular basis of intraepithelial spreading (IES) of carcinomas in situ (CIS) of the urinary bladder, which were considered to be precursors of nodular invasive carcinomas. MATERIALS AND METHODS: The propensity for IES of human transitional carcinoma cells was examined by inoculation into murine renal pelvis and urinary bladder, and the biological character of the cells with a high propensity for IES was explored in vitro. RESULTS: Three of 6 cell lines exhibited a high propensity for IES. When cultured on laminin, these IES cells scattered, whereas 3 non-IES cells and 2 immortalized transitional epithelial cells did not. IES cells showed strong adhesiveness, haptotaxis and enhanced migration on laminin compared with both non-IES and immortalized transitional epithelial cells. In IES cells, expression of the integrin beta4 subunit was markedly reduced and the integrin alpha6beta1 complex was predominant compared with the integrin alpha6beta4 complex. Transfection of IES cells with integrin beta4 subunit cDNA inhibited their ability to migrate on laminin and their propensity for IES. In addition, expression of the integrin beta4 subunit was reduced in surgically resected specimens of CIS of the urinary bladder. CONCLUSION: The results indicate that a reduction in integrin beta4 plays a role in IES of CIS of the urinary bladder through enhanced migration on laminin.

Antigens, CD↗
PubMed1999

[The effect of milrinone for the shock patients after cardiac surgery].

The effect of milrinone in the 16 postoperative shock patients of cardiovascular surgery was studied. The preoperative hemodynamic status were 12 of cardiogenic shock, 2 cases of chronic heart failure and 2 cases of unstable angina pectoris. The operative procedure were 8 cases of coronary artery bypass grafting, 4 cases of valvular surgery, 2 cases of closure of ventricular septal perforation, 2 cases of Bentall operation and 1 case of ascending aortic replacement. The postoperative hemodynamic status were 15 cases of cardiogenic shock, 10 cases of hemorrhagic shock and 1 case of septic shock. Continuous intravenous infusion of 0.5 microgram/kg/min without initial bolus loading was administered immediately after the entrance of the intensive care unit. Significant increase in the maximum blood pressure 3 hours after the infusion were observed (84 +/- 17 mmHg vs 94 +/- 12, p = 0.033). The maximum blood pressure was increased gradually until 24 hours after the infusion. Significant increase in the peripheral body temperature 3 hours after the infusion were observed (32.5 +/- 2.0 degrees C vs 35.9 +/- 1.1 degrees C, p = 0.001). The difference between the peripheral temperature and the central body temperature diminished until 24 hours after the infusion. No significant change in the central venous pressure, pulmonary arterial pressure, pulmonary and cardiac index wedge pressure were observed. No significant change in the platelet number was observed until 3 days after the infusion. Twenty patients (75%) were discharged. Four hospital deaths included 1 cardiac and 3 septic cause were seen. These data suggest that the administration of milrinone for the shock patients after cardiac surgery showed safe and that the continuous intravenous infusion of 0.5 microgram/kg/min without bolus loading showed effective for the recovery of the peripheral circulation.

Aged↗
PubMed1999

[Clinical study of six thymic carcinomas including long-term survivors].

Six cases of thymic carcinoma (mean age 48.5 years old, one male and 5 females) were treated in our hospital from September 1990 to September 1998. The histological subtypes of thymic carcinoma were squamous cell in 4, undifferentiated in one, and small cell in one. All cases underwent midsternal thoracotomy, 4 had total resection of the tumor and 2 had exploratory thoracotomy due to tumor invasion of the aorta and the main pulmonary artery. Within 2 years after operation, 2 cases without radiation therapy were died of the carcinoma and one case was died of asthma. However, two cases of squamous cell carcinoma have been alive and disease free for 3 and 5 years since the operation followed by mediastinal irradiation. We think that radiation therapy is very effective to control the disease because one of them underwent only exploratory operation prior to irradiation. Another one case who survives 5 years after total resection of the tumor following irradiation revealed swelling of numerous mediastinal lymph nodes, pathologically consisted of non-caseating epithelioid cell granulomas without metastasis of carcinoma, at the time of operation. These lymph nodes were diagnosed as "sarcoid-like reaction" because there was no clinical evidence of generalized sarcoidosis. The "sarcoid-like reaction" may contribute to the 5-year survival of the patient because it is thought to be a local immune response against the cancer cells. A remaining patient, alive 6 months after total resection of the thymic small cell carcinoma following irradiation, received preoperatively three cycles of the intra-arterial administration using CBDCA via bilateral internal mammary arteries. This induction chemotherapy had no response of the tumor size, but it was considered to have a possibility of reducing the size of thymic carcinoma by the use of other agents (CDDP, VDS etc.) because the tumor was fed mainly by the highly developed internal mammary arteries.

Adult↗
PubMed1999

[Mitral valve annuloplasty with U-shaped flexible band using Duran ring].

To preserve the physiologic function and correct annular dilatation, U-shaped flexible band was applied for mitral valve annuloplasty in 6 cases. U-shaped flexible band was made by cutting Duran ring to the proper length of posterior annulus using Carpentier-Edwards ring sizer. Echocardiographic mitral regurgitation decreased from 3.8 +/- 0.4 to 0.7 +/- 0.5 after repair. All patients discharged without any complications. This annuloplasty method is effective for mitral insufficiency.

Aged↗
PubMed1998

An esterase from Escherichia coli with a sequence similarity to hormone-sensitive lipase.

An esterase from Escherichia coli that is a member of the hormone-sensitive lipase (HSL) family was overproduced, purified and characterized. It is encoded by the ybaC gene and composed of 319 amino acid residues with an Mr of 36038. The enzymic activity was determined by using various p-nitrophenyl esters of fatty acids as a substrate at 25 degreesC and pH 7.1. The enzyme showed hydrolytic activity towards substrates with an acyl chain length of less than 8, whereas it showed little hydrolytic activity towards those with an acyl chain length of more than 10. In addition, it showed little hydrolytic activity towards trioleoylglycerol and cholesterol oleate. Determination of the kinetic parameters for the hydrolyses of the substrates from C2 to C8 indicates that C4 and C5 substrates are the most preferred. Close agreement between the Mr determined by SDS/PAGE (37000) and column chromatography (38000) suggests that the enzyme exists in a monomeric form. It is an acidic protein with a pI value of 4.1. The far-UV CD spectrum suggests that its helical content is 26.1%. Comparison of the amino acid sequence of this enzyme with those involved in the HSL family allows us to propose that Ser165, Asp262 and His292 constitute the catalytic triad of E. coli esterase.

Amino Acid Sequence↗
PubMed1998

5-fluorouracil and low-dose recombinant interferon-alpha-2a in patients with hormone-refractory adenocarcinoma of the prostate.

BACKGROUND: The effectiveness of a chemotherapy regimen including 5-fluorouracil (5-FU) and recombinant interferon-alpha-2a (rIFN-alpha-2a) was evaluated in hormone-refractory prostate cancer patients. METHODS: Patients received a continuous intravenous infusion of 5-FU at 600 mg/m2/day for 5 days (D1-D5), followed by a bolus injection of 5-FU on D15 and D22. Patients received intramuscular injection of rIFN-alpha-2a at 3 million IU on D1, D3, D5, D15, and D22. This schedule was repeated every 4 weeks. RESULTS: Between 1993 and 1995, 23 patients with hormone refractory prostate cancer were enrolled in this study. Two of five patients with nodal disease exhibited partial responses according to the NPCP criteria. Fourteen of 17 patients with bone disease showed stable disease. Of 21 patients assessible for response, 9 patients had a decrease in the PSA level greater than 50% of baseline. Bone pain disappeared partially or completely in 8 of 14 patients with this symptom at entry. The median overall survival was 18 months. The associate toxicity was well tolerable. CONCLUSIONS: Combination chemotherapy of 5-FU and low dose rIFN-alpha-2a in patients with hormone-refractory prostate cancer proved feasible, and with acceptable toxicity.

Adenocarcinoma↗
PubMed1998

Experience with kidney transplantation in children and adolescents.

BACKGROUND: Paediatric kidney transplantation has different aspects in adults in terms of underlying primary renal disease, surgical technique, perioperative care and graft prognosis. Significant urological problems are present in a high percentage of paediatric recipients. This study was undertaken to characterize paediatric kidney transplantation as performed at our institutes. METHODS: Twenty-eight patients (age range 4-17 years, 10 girls, 18 boys) were included in this study. We analyzed (1) urologic procedures performed prior to or simultaneously with transplantation, (2) intraoperative changes in haemodynamics, (3) postoperative complications and (4) acute allograft rejection and graft prognosis. RESULTS: Of 4 patients with lower urinary tract abnormalities (neurogenic bladder in 3, posterior urethral valve in 1), 2 underwent augmentation ileocystoplasty prior to transplantation. The Mitrofanoff procedure as a diversion for neourethra was also performed in 2 of the 4 patients. All these 4 patients were managed with clean intermittent catheterization. Central venous pressure changes before and after graft vessel declamping were much greater in patients with body weight below 25 kg than in those above 25 kg. Five surgical complications and 6 infections were encountered postoperatively and hypertension was lasting in 6. Thirteen patients experienced 19 periods of acute allograft rejection. All of the 24 patients in the cyclosporin era (1986-) overcame rejections and they are all alive with good graft function. CONCLUSIONS: As long as proper pretransplant patient evaluation and management, and intensive perioperative care are undertaken, good prognosis of renal allograft can be achieved in young patients.

Adolescent↗