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Biomedical subjects

T Koyanagi

Publications and source records attributed to T Koyanagi.

At least 55 records · Page 3Linked to original sources
PubMed2000

The relationship between technical parameters of external beam radiation therapy and complications for localized prostate cancer.

BACKGROUND: This study was performed to review retrospectively the clinical course of chronic rectal bleeding as a complication of external beam radiation therapy for localized prostate cancer and to analyze the relationship between technical parameters of radiation therapy and the complications. METHODS: Seventy-one patients with stages A2, B and C were treated with local-field radiotherapy (total dose 52.5-66 Gy, daily dose 2.0-3.28 Gy, field area 30-81 cm2, number of fields 3-15 ports, planning simulations X-ray or CT-based) between 1989 and 1998 at three institutions. The protocols were consistent during this same period at these institutions. RESULTS: Multivariate analysis revealed pretreatment PSA and Gleason sum to be statistically significant predictors of 5 year prostatic specific antigen (PSA) relapse-free rates in a median follow-up period of 42 months (range 12-119 months). The significant risk factors for higher grading of acute morbidity were a biological equivalent dose, alpha/beta = 10(BED10) > or =65 Gy, dose per fraction > or =3.0 Gy, field area > or =42 cm2, fewer ports and X-ray planning simulation. However, no parameter was associated with higher grading of late morbidity. Eleven patients (15.4%) experienced a late GI complication: grade 1 (4.2%), grade 2 (9.8%), grade 3 (1.4%). The median time to occurrence of rectal bleeding was 12 months after radiotherapy and the mean duration of morbidity was 11 months. CONCLUSIONS: Higher total dose and dose per fraction, larger field area, fewer ports and X-ray simulation increased the grades of acute morbidity. A majority of chronic rectal bleedings were transient and responded to conservative treatment.

Aged↗
PubMed2000

Cloning and random mutagenesis of the Erwinia herbicola tyrR gene for high-level expression of tyrosine phenol-lyase.

Tyrosine phenol-lyase (Tpl), which can synthesize 3, 4-dihydroxyphenylalanine from pyruvate, ammonia, and catechol, is a tyrosine-inducible enzyme. Previous studies demonstrated that the tpl promoter of Erwinia herbicola is activated by the TyrR protein of Escherichia coli. In an attempt to create a high-Tpl-expressing strain, we cloned the tyrR gene of E. herbicola and then randomly mutagenized it. Mutant TyrR proteins with enhanced ability to activate tpl were screened for by use of the lac reporter system in E. coli. The most increased transcription of tpl was observed for the strain with the mutant tyrR allele involving amino acid substitutions of alanine, cysteine, and glycine for valine-67, tyrosine-72, and glutamate-201, respectively. A tyrR-deficient derivative of E. herbicola was constructed and transformed with a plasmid carrying the mutant tyrR allele (V67A Y72C E201G substitutions). The resultant strain expressed Tpl without the addition of tyrosine to the medium and produced as much of it as was produced by the wild-type strain grown under tyrosine-induced conditions. The regulatory properties of the mutant TyrR(V67A), TyrR(Y72C), TyrR(E201G), and TyrR(V67A Y72C E201G) proteins were examined in vivo. Interestingly, as opposed to the wild-type TyrR protein, the mutant TyrR(V67A) protein had a repressive effect on the tyrP promoter in the presence of phenylalanine as the coeffector.

Alleles↗
PubMed2000

Is suprapubic cystostomy an optimal urinary management in high quadriplegics?. A comparative study of suprapubic cystostomy and clean intermittent catheterization.

INTRODUCTION: Long-term outcome of spinal cord injury (SCI) patients was compared between those managed by suprapubic cystostomy (SPC) and clean intermittent catheterization (CIC) with particular emphasis on an incidence of urinary tract complications and patients perception for urinary management. MATERIALS AND METHODS: The study comprised 61 SCI patients; 34 patients managed with SPC (group A), while 27 with CIC (group B). After stabilization of their condition, all were followed annually on an outpatient basis with clinical history, urinalysis, urinary imaging and renal function studies. Mean follow-up periods were 8.6 and 9.9 years for groups A and B, respectively. Between groups, a comparative study was performed on the incidence of urinary complications such as renal dysfunction, hydronephrosis, vesicoureteral reflux, symptomatic genitourinary infection and urinary stone. Satisfaction with urinary management was also estimated using the questionnaires during follow-up. RESULTS: Renal dysfunction, hydronephrosis and vesicoureteral reflux were not found in either group. Symptomatic genitourinary infection was seen in 4 (12%) of group A and 7 (26%) of group B, respectively. The incidence of renal stone was 3 (9%) in group A and 1 (4%) in group B. A significant difference was not found between two groups in these urinary complications. On the contrary, bladder stone was seen more frequently in group A (65%) than in group B (30%) with a significant difference (p<0.001). The degrees of incontinence, bother score of daily activities, and overall satisfaction showed no significant difference between the two groups. CONCLUSION: Except for bladder stones, SPC is a valuable option of urinary management for quadriplegic patients, the results of which were comparable to paraplegic SCI patients managed with CIC.

Adolescent↗
PubMed2000

Endothelin A receptor antagonist reduces renal vasoconstriction induced by mechanical manipulation of renal artery.

The purpose of this study was to make a model of renal vasoconstriction induced by mechanical manipulation of the renal artery and to investigate the influence of endothelin (ET) in renal vasoconstriction. Renal arteries of anesthetized rats were stretched with a 30-gram weight for 5 min, and released. Renal blood flow (RBF) was monitored with a laser flowmeter. To determine the role of ET, a selective ET(A) receptor antagonist, BQ-123 (0.1 and 1 mg/kg) was administered into the aorta. The manipulation was invariably followed by a flow reduction of about 57% after temporary hyperemia. RBF returned to the basal level 5 min after the release. BQ-123 partially, but significantly, inhibited the mechanical manipulation-induced reduction of RBF in a dose-dependent manner. These results suggest that endogeneous ET may play an important role in renal vasoconstriction induced by mechanical manipulation of the renal artery.

Animals↗
PubMed2000

Molecular cloning and heterologous expression of pea seedling copper amine oxidase.

The cDNA coding for copper amine oxidase has been cloned from etiolated pea seedlings (Pisum sativum). The deduced amino acid sequence, consisting of 674 residues including the signal peptide, agreed well with those reported for the enzymes from a different cultivar of P. sativum and other plant sources, except for several evolutionary replacements located mostly on the molecular surface. A heterologous expression system for the cloned pea enzyme was constructed with the yeast Pichia pastoris, using the AOX1 promoter and the yeast alpha-factor secretion signal. Adding copper to the culture medium increased the secretion of an active, quinone-containing enzyme. Furthermore, the inactive enzyme produced in a copper-deficient medium was activated considerably by subsequent incubation with excess cupric ions. These results strongly suggest that the Tyr-derived redox cofactor, 2,4,5-trihydroxyphenylalanylquinone (topa quinone, TPQ), is produced in the plant enzyme by post-translational modification that proceeds through the copper-dependent, self-processing mechanism, as in the enzymes from bacteria and yeast.

Amine Oxidase (Copper-Containing)↗
PubMed2000

[A case of chronic localized thoracoabdominal aortic dissecting aneurysm].

A rare case of chronic localized thoracoabdominal aortic dissecting aneurysm was surgically treated. The patient was a 76-year-old woman. She was reffered to our hospital because of the abnormality of the chest roentogenogram. Chest CT and aortography revealed localized thoracoabdominal dissecting aneurysm 70 mm in diameter. Patch closure of intimal tear was carried out under partial cardiopulmonary femoro-femoral bypass. The patient discharged on the 23rd post operative day without any complications.

Aortic Dissection↗
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

Vesicourethral function in diabetic patients: association of abnormal nerve conduction velocity with vesicourethral dysfunction.

This study was undertaken to examine diabetic vesicourethral dysfunction in association with nerve conduction velocity. Uroflowmetry, water cystometry, International Prostate Symptom Score (IPSS), and nerve conduction velocity were analyzed in 29 diabetic patients (21 men and eight women; a mean age, 58.0 years). Nerve conduction velocity was measured for sensory nerve conduction velocity (SCV) of the sural nerve and motor nerve conduction velocity (MCV) of the peroneal nerve. Normal voiding was defined as continuous flow at the normal flow rate and residual urine <50 mL. Results of uroflowmetry and cystometry were compared with those of nerve conduction velocity. Eleven of 29 patients (38%) had voiding dysfunction. A vesical denervation supersensitivity test was negative in all patients. The mean IPSS was not significant different between patients with or without voiding dysfunction. Incidence of bladder volume at first desire to void >300 mL and maximum bladder capacity >500 mL were significantly higher in patients with abnormal SCV than those with normal SCV (P < 0.03 and 0.001, respectively). Eleven of 16 patients with abnormal MCV showed voiding dysfunction, whereas all patients with normal MCV showed normal voiding (P < 0.001). These results suggest that lower urinary tract symptoms alone cannot predict diabetic vesicourethral dysfunction and that diabetic vesicourethral dysfunction is highly correlated with abnormal nerve conduction velocity. Neurourol. Urodynam. 18:639-645, 1999.

Adolescent↗
PubMed1999

Reappraisal of Tc-99m DMSA scintigraphy for follow up in children with vesicoureteral reflux.

We reviewed Tc-99m DMSA scintigraphy in children with vesicoureteral reflux (VUR) in order to assess whether repeated Tc-99m DMSA scans are necessary for the follow up of these patients. Ninety-seven children who were followed up for more than one year (1-7.4 years, average 2.8 years) after the first DMSA scan were included in the study. Fifty-one patients had been diagnosed as primary VUR and 46 as secondary VUR. Age at the first examination ranged from 0 to 14 years (average 5.1 years). Planar images were taken 2 hours after injection. The % renal uptake per injected dose (%RU) was calculated from posterior images. Kidneys in 11 patients (11.3%) changed morphologically during the follow up. Of these, new photon deficient areas (PD) were detected in only 4 patients (4.1%). All of these 4 patients had neurogenic bladder and were managed with self-catheterization. Of the remaining 7 patients, cortical thinning progressed in 5 patients (5.2%) and PDs resolved in 3 patients (3.1%). In one of these 7 patients, PD resolved in one kidney and cortical thinning progressed in the contralateral kidney. Of 97 patients reviewed, % RU decreased more than 20% during the follow up in 6 patients (6.2%). All were diagnosed as secondary VUR due to neurogenic bladder. %RU decreased only in the contracted kidneys at the initial scan. Two of them underwent renal transplantation because of severe renal failure. In conclusion, new PD rarely developed and % RU decreased in only a few patients during the follow up of children with VUR. Repeated Tc-99m DMSA scintigraphy therefore seems to have little benefit in the follow up of children with VUR. It should be performed in selected patients with high risk of urinary tract infection or renal failure.

Adolescent↗
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↗