Search PubMed⌕ Search

Biomedical subjects

T Koyanagi

Publications and source records attributed to T Koyanagi.

At least 181 records · Page 10Linked to original sources
PubMed1994

Change in the three-dimensional shape of the stomach in the developing human fetus.

To reveal the developmental characteristics of the fetal stomach in utero, this study was made on 879 subjects from 20 to 40 weeks' gestation. By applying the system of 'Modeling a three-dimensional shape from a silhouette by detecting symmetry' which we devised, we reconstructed the three-dimensional shape, from the outline of the longitudinally transected fetal stomach, obtained from the real-time ultrasound image. Age-related changes in gastric volume and sphericality (parameters produced by the above mentioned method) were analyzed using piecewise linear regression. The fetal stomach volume increased linearly from 20 to 37 weeks' gestation and decreased thereafter to 40 weeks' gestation, with a critical point at 37 weeks' gestation. The sphericality of the fetal stomach shape was also seen to decrease linearly from 20 weeks' to the critical point at 27 weeks' gestation, thereafter remaining constant regardless of the advance in gestation to term. These findings indicate that at 20-27 weeks' gestation, the stomach is of a fusiform-like shape. From 27 weeks' gestation onwards, greater and lesser curvatures become apparent, clearly identifying the cardiac and pyloric regions. The decrease in stomach size after 37 weeks' gestation is also in good accord with the decrease in amniotic fluid volume. The analytical method presented here can help to understand the pathogenesis of gastrointestinal lesions in the developing fetus.

Embryonic and Fetal Development↗
PubMed1994

Prophylactic chemotherapy with anthracyclines (adriamycin, epirubicin, and pirarubicin) for primary superficial bladder cancer. The Hokkaido University Bladder Cancer Collaborative Group.

A multicentric randomized trial was conducted to evaluate the efficacy of intravesical chemoprophylaxis for primary superficial bladder cancer. The 299 eligible patients with primary superficial bladder cancer were randomized into four groups (A, B, C, and D) after pathological confirmation. Intravesical instillation of drugs, which were dissolved in 20 ml physiological saline (PS; group A, 20 mg Adriamycin; group B, 20 mg epirubicin; group C, 20 mg pirarubicin; group D (control), PS alone], was performed once a week for 2 weeks after trasurethral resection and then once every 2 weeks for 14 weeks, once monthly for 8 months, and once every 3 months for 1 year. No significant difference in the patients' characteristics was found among the four groups. The follow-up period ranged from 3 to 31 months (mean, 14 months). The nonrecurrence rates were estimated by the method of Kaplan and Meier. The relative effects of five variables (the tumor status, size, grade, and stage and the treatment) on the efficacy of the chemoprophylaxis regimens were evaluated using a multiple regression model. Although the nonrecurrence rates determined for groups A and B were significantly higher than that found for group D (P < 0.05), no significant difference in the nonrecurrence rate was detected among groups A, B, and C. The multiple regression model indicated that the most important factors in preventing tumor recurrence at 12 or 24 months were the intravesical instillation of an anthracycline and the tumor status (solitary). These results demonstrate that intravesical instillation of the tested anthracyclines is effective for at least 2 years as prophylactic chemotherapy for primary superficial bladder cancer.

Administration, Intravesical↗
PubMed1994

Fetal heart rate variation described using a probability distribution matrix.

We devised a new method using a probability distribution matrix to simultaneously describe variation in the characteristics of fetal heart rate (FHR) and beat-to-beat difference (DFHR) between the present and the immediately following FHR. The FHRs were plotted in columns, DFHRs in rows and probabilities in the corresponding elements of the matrix. The age-related changes of FHR data obtained from 743 fetuses at 23-40 weeks gestation were analysed using a pulsed Doppler cardiotocograph with an autocorrelation system. While keeping an almost symmetrical spread around 0 beats/min of DFHR, three particular probability distribution patterns of FHR versus DFHR emerged with advance in gestation: (i) oval with a monomodal peak from 23/24 to 29/30 weeks, (ii) ellipsoid with a monomodal peak and plateau from 31/32 to 33/34 weeks and (iii) elongated ellipsoid with bimodal peaks from 35/36 weeks of gestation onwards. The probability distribution matrix presented enables one to condense any amount of FHR data into one uniform description. This allows analysis of data, en bloc, achieving a quantitative inter-group comparison, on an equivalent scale.

Age Factors↗
PubMed1994

The relationship between age-related heart rate changes and developing brain function: a model of anencephalic human fetuses in utero.

We attempted to identify the brain segment which controls heart rate changes in human fetuses with advancing gestation. Twelve anencephalic and 165 normal fetuses (control-group fetuses) between 25-32 weeks' gestation were studied. The instantaneous fetal heart rate (FHR) data were obtained from each fetus for a continuous 90-120 min period, using an external cardiotocograph. Calculations included the 'individual probability distribution matrices' in which the FHRs at 1 beat/min intervals between 110 and 180 beats/min, the beat-to-beat differences (DFHRs) between +/- 5 beats/min and the probability values were arranged in rows, columns and the corresponding elements, respectively. Using 2-gestational-week intervals probability distribution matrices (age-group probability distribution matrices) obtained from 335 normal fetuses in our previous study as a reference, the difference between a given 'individual probability distribution matrix' and the corresponding age-group probability distribution matrix' was quantified as the 'difference rate' according to the formula in the text. From 25-26 to 27-28 weeks' gestation, the 'difference rates' in four anencephalic fetuses, with only the spinal cord preserved, were significantly higher in value than those of control-group fetuses, whereas the rates in four fetuses with both the spinal cord and medulla oblongata preserved, indicated no significant differences. From 29-30 to 31-32 weeks' gestation, the rates of the four fetuses with the spinal cord and medulla oblongata preserved, showed significant differences from the control-group fetuses. These findings suggest that there is a critical period between 27-28 and 29-30 weeks' gestation with regard to the developing brain function pertaining to FHR changes. In the early stage, the medulla oblongata plays a role in FHR changes, whereas, in the latter stage, the brain cephalad to the medulla also appears to take on the role of FHR regulator.

Anencephaly↗
PubMed1994

Coronary artery bypass grafting in chronic renal dialysis patients: intensive perioperative dialysis and extensive usage of arterial grafts.

Twenty-three chronic renal dialysis patients underwent coronary artery bypass grafting (CABG). Eighteen patients were maintained on hemodialysis and 5 patients received continuous ambulatory peritoneal dialysis. Eighteen patients (78%) had triple vessel disease or left main disease. The mean number of revascularized vessels was 2.2 +/- 0.8, and the graft materials used were left internal thoracic artery (21), right internal thoracic artery (7), right gastroepiploic artery (7), and saphenous vein (15). The utilization index of arterial grafts (percentage of patients with at least one arterial graft) was 95.7%. Intraoperative hemodialysis (HD) was performed during cardiopulmonary bypass in all patients. In 17 patients on HD preoperatively, peritoneal dialysis (PD) was initiated immediately after the operation, and maintained until the hemodynamics stabilized sufficiently to resume HD (mean: 5.7 +/- 3.4 days after operation). In the patients with a gastroepiploic artery pedicle, PD could be established without leakage of dialysis fluid into the pericardial cavity by means of making a smaller hole in the diaphragm, passing the skeletonized portion of the graft through the hole and sealing the hole using fibrin glue. There were no hospital deaths. Angiography revealed an overall graft patency rate of 95.8% (46/48), and all arterial grafts were patent. There were 4 late deaths (1 cardiac, 3 cerebral hemorrhage). In conclusion, CABG can be accomplished in chronic renal dialysis patients with excellent early and long-term results through an intensive perioperative dialysis program and extensive usage of arterial grafts.

Adult↗
PubMed1994

One-stage repair of hypospadias: is there no simple method universally applicable to all types of hypospadias?

A simple method of hypospadias repair is described. The operative technique consists of 7 steps, including 1) outlining the skin incision and dartos mobilization; 2) artificial erection, harvesting parameatal foreskin flap and release of chordee as needed; 3) glans splitting and creation of glanular wings; 4) 1-stage urethroplasty with parameatal foreskin flap; 5) meatal glanuloplasty; 6) creation of Byars' flaps of the skin, and 7) skin closure. Central to the technique is the feasibility of the choice of 1-stage urethroplasty with meatal based manta-wing flap or with parameatal based and fully extended circumferential foreskin flap even after the skin incision is made, which enables its application to all types of hypospadias. Of 120 patients the 1-stage urethroplasty was performed with meatal based manta-wing flap in 50, and with parameatal based and fully extended circumferential foreskin flap in 70. Primary success was obtained in 82% of the cases with meatal based manta-wing flap, and in 53% with parameatal based and fully extended circumferential foreskin flap. Complications requiring secondary repair occurred in 42 cases (9 with meatal based manta-wing flap, and 33 with parameatal based and fully extended circumferential foreskin flap) but repair was successful in 32. Thus, the overall success rate was 91% (96% with meatal based manta-wing flap, and 87% with parameatal based and fully extended circumferential foreskin flap). Additional repair (10 secondary, 2 tertiary and 1 quaternary) is planned in 13 cases. The technique of 1-stage urethroplasty with parameatal foreskin flap is recommended as a simple and reliable treatment for hypospadias with a reasonable success rate.

Child↗
PubMed1994

The relevance of preoperative cystometrography in patients with benign prostatic hyperplasia: correlating the findings with clinical features and outcome after prostatectomy.

Preoperative water cystometrograms in 437 patients with benign prostatic hyperplasia (BPH) were examined in a retrospective study. The cystometrographic results were analyzed regarding the preoperative clinical features: patient age, presence or absence of urinary incontinence, history of urinary retention and rate of residual urine. The prognostic value in improvement in voiding difficulty and postoperative urinary incontinence was also analyzed at 1 and 6 months after elective prostatectomy. Subjective symptoms of the patients were the primary reasons for prostatectomy, the majority of which were performed by a single competent resectionist (K. T.) who evaluated the outcome but was blinded to the cystometric findings. Of these patients 263 (60.2%) had detrusor instability (group 1), while 174 did not (group 2). Vesical denervation supersensitivity to bethanechol chloride was noted in 47 of 375 patients (12.5%). The difference in clinical features was significant between the 2 groups, with group 1 showing older patient age (p < 0.01), and a greater incidence of urinary incontinence (p < 0.001) and retention (p < 0.001). The difference between groups 1 and 2 in mean bladder capacity (p < 0.01), compliance (p < 0.01) and a greater positive rate of vesical denervation supersensitivity (p < 0.001) was also significant. The clinical and cystometrographic parameters studied worsened with advancing patient age. Although the majority of the patients (94.7%) were relieved of obstructive symptoms after transurethral prostatectomy (6 months later), 113 (25.9%) were not at 1 month. Compared to 324 patients with early improvement (74.1%), those without improvement at 1 month were characterized by older age (p < 0.01), greater prevalence of preoperative incontinence (p < 0.05), retention (p < 0.01), greater residual rate (p < 0.05), a less compliant bladder (p < 0.01) and a higher positive rate of vesical denervation supersensitivity (p < 0.05). Cystometrographic findings, however, had no relevance to late (6 months) outcome of voiding difficulty. On the other hand, postoperative incontinence was noted in 100 patients (22.9%) at 1 month after transurethral prostatectomy, with the majority having episodes similar to those experienced preoperatively (70.0%) as well as detrusor instability (87.0%). They also were older (p < 0.01), and had a less compliant bladder (p < 0.01) and a higher positive rate of vesical denervation supersensitivity (p < 0.01) than did continent patients. Only 18 elderly patients (4.1%) remained incontinent 6 months later, all with a less compliant (p < 0.01) and more unstable (p < 0.01) bladder initially. The genesis of this detrusor dysfunction was believed to be aging in male patients, in whom BPH evolves and progresses. In conclusion, preoperative cystometrography in patients with BPH is valuable in that it correlated well with the clinical features and it can predict to some extent the outcome of obstructive symptoms and urinary incontinence after transurethral prostatectomy.

Age Factors↗
PubMed1994

An electromyographic study on the urethral rhabdosphincter in normal and chronically rhizotomized cats: analysis of electrical potentials evoked by sympathetic nerve stimulation.

To investigate functional aspects of sympathetic nerve influence on the urethral rhabdosphincter, we examined electrical potentials of the male feline rhabdosphincter evoked by hypogastric nerve (HGN) stimulation using electromyography. Hypogastric nerve stimulation (1 Hz) elicited electrical potentials of the rhabdosphincter in both normal and chronically rhizotomized cats. In normal cats, the evoked potentials were not affected by transection of the bilateral pudendal nerves. The amplitudes of the evoked potentials were significantly larger in rhizotomized cats (p < 0.001), while the threshold stimuli and latency periods were not. These evoked potentials were prazosin- and atropine-resistant, but were abolished by hexamethonium and pancuronium in both groups. In normal cats, high frequency stimulation (10 to 20 Hz) of the HGN increased the activity of the rhabdosphincter when the bladder was empty, but not when the bladder was full enough to trigger the vesicourethral relaxation reflex. This excitatory effect of HGN stimulation was blocked by prazosin. These data suggest that the potential of the rhabdosphincter evoked by HGN stimulation (1 Hz) is produced through synapse from sympathetic preganglionic to cholinergic postganglionic neurons, and that, after sacral rhizotomy, cholinergic postganglionic terminals form more effective functional connections to somatically denervated motor end-plates of the rhabdosphincter. The sympathetic nerve is also believed to play a role in modulating urethral afferent activities through action on urethral smooth muscle.

Animals↗
PubMed1994

Preexisting neurogenic voiding dysfunction in children with imperforate anus: problems in management.

We evaluated 22 boys and 2 girls 1 month to 8 years old with imperforate anus to determine the relationship between neurogenic voiding dysfunction and bony sacral or spinal cord anomalies. Lower urinary tract function before anorectoplasty was normal in 12 children (group 1), abnormal (detrusor-sphincter dyssynergia) in 9 (group 2) and not evaluated in 3 (group 3). High lesions of imperforate anus were present in 22% of the patients in group 1 and in 100% of those in group 2. Plain radiography revealed partial sacral agenesis in 1 child in group 1 and 4 in group 2. Magnetic resonance imaging detected occult spinal dysraphism in 1 patient in group 1 and 2 in group 2. (Occult spinal dysraphism included sacral lipoma, tethered cord, syringomyelia and thick filum terminale.) Seven children in group 2 had vesicoureteral reflux before anorectoplasty. All children in group 2 were placed on clean intermittent catheterization for the management of neurogenic voiding dysfunction. Normal upper urinary tract function was maintained in all patients in group 1 and 6 in group 2. The remaining 3 children in group 2 had high grade reflux at presentation associated with severe renal damage or noncompliance with clean intermittent catheterization. These findings indicate that in children with imperforate anus lower urinary tract function should be evaluated before anorectoplasty because of the high incidence of associated congenital neurogenic voiding dysfunction and the potential risk for renal deterioration. When possible, neurogenic voiding dysfunction should be managed with clean intermittent catheterization to prevent renal damage.

Anus, Imperforate↗
PubMed1994

Quantification of fetal heart rate variation using a probability distribution matrix.

Analysis of FHR variability attempts to be able to distinguish which FHR changes are physiological and which are pathological. From the results of such studies, it is hoped that clinicians will be provided with the means to identify accurately which fetuses are healthy, which are at risk and which are actually in distress at any gestational age. The probability distribution matrix presented has the outstanding advantage of enabling one to condense any amount of FHR data into one uniform description for analysis en bloc. Not even one FHR is sacrificed; each one contributes to the FHR vs. DFHR distribution pattern. Where the probability distribution matrix is made from many FHR samples taken from healthy fetuses under natural day-to-day maternal circumferences, as we have done, this matrix can be considered as a physiologically unbiased reference. The subtraction matrix is characterized by the difference in FHR vs. DFHR distribution patterns between two probability distribution matrices compared, representing the equal residue of net absolute value. The larger the difference in FHR vs. DFHR distribution between two probability distribution matrices, the larger these kinds of residue values, and if two probability distribution matrices are identical, all the elements in the subtraction matrix indicate the residue values of zero. Our probability distribution matrix approach confirms the results of previously reported studies which utilized other analytical strategies. Therefore, we can evaluate quantitatively age-related FHR changes used as variables, such as the subtraction matrix and difference rate. By varying intervals between paired FHRs (e.g. selecting the original FHR--skip--select the following FHR--skip 2 FHR--select the next FHR, etc.), the probability distribution matrix could be adopted as a general tool for analysis of sequential changes in large numbers of FHR for further studies.

Bias↗
PubMed1994

Long term urinary prognosis of cervical cord injury patients.

We made a retrospective comparative study of 88 cervical cord injury patients concerning their long term urological prognosis. In all, 129 urinary complications have occurred in 54 cases (61.4%). The incidence of urinary complications was high in those with higher levels of injury (except C integral of 4 lesions), a complete injury, a younger age of onset and a longer period after injury. Patients who had an indwelling catheter and a suprapubic cystostomy showed a higher rate of urinary complications. Urodynamically, there was no significant difference between the presence and absence of detrusor hyperreflexia. Those with detrusor-sphincter dyssynergia (DSD) also showed no difference compared to those without DSD. For the prevention of urinary complications in cervical cord injury patients, proper urinary management with clean intermittent catheterisation (CIC), or low pressure voiding is necessary in the early period after the onset of the injury.

Adult↗
PubMed1994

Urinary control after radical transurethral resection of the prostate in male paraplegics: urodynamic evaluation of its effectiveness in relieving incontinence.

We report our investigation of urinary incontinence in 51 male paraplegics with radical transurethral resection of the prostate. Pre-operatively, 28 cases (55.9%) had moderate or severe incontinence, which persisted post-operatively only in 21 cases (41.2%) and was less severe. Post-operatively, bladder compliance was improved from 22.1 +/- 22.6 ml/cmH2O to 36.4 +/- 38.5 ml/cmH2O, and the maximum pressure of uninhibited detrusor contraction was reduced from 40.2 +/- 21.5 cmH2O to 18.3 +/- 19.0 cmH2O. These significant improvements are thought to contribute to the relief of urinary incontinence, regardless of the reduction in maximum urethral closure pressure.

Adult↗
PubMed1994

Management and outcome of antenatally diagnosed hydronephrosis.

From March 1989 to December 1992, we encountered 25 kidneys in 21 patients with a suspicious ureteropelvic junction (UPJ) obstruction detected only on prenatal ultrasound. In all these patients other urological abnormalities were excluded by voiding cystourethrography and other radiological findings. Diuretic renography (DR) was initially performed at an age ranging from 15 days to 32 months in all patients and repeated a total of 39 times. Both the split renal function (SRF) and diuretic drainage half-time clearance (DT1/2) of radioagent were within their normal ranges in the case of 15 (60%) of the kidneys on initial DR. In these kidneys, there were no aggravated signs on repeated DR. Decreased SRF was found in 3 kidneys (12%) on initial DR. Of these, the renal function spontaneously reverted to normal in 2 cases with bilateral hydronephrosis. Another 1 kidney revealed significant UPJ obstruction assessed by pressure flow study and continuous nephrostomy drainage had brought relief from the obstruction 1 year later. Prolonged DT1/2 with normal SRF was found in 7 (28%) kidneys. The renal function did not deteriorate and the diuretic response improved on repeat DR except for 1 kidney, whose function deteriorated and on which ultimately, pyeloplasty was performed at 7 months of age. Prenatally diagnosed hydronephrosis is usually asymptomatic and clinically significant UPJ obstruction should be always verified. Although even today there is still no examination which can detect a definite obstruction, we can identify one as significant by careful repeat examinations and thus avoid unnecessary surgery without causing any renal deterioration.

Child, Preschool↗
PubMed1994

In vivo effect of a selective endothelin receptor antagonist, BQ-123, on renal function in cyclosporin A-treated rats.

To investigate the possible involvement of endogenous endothelin (ET) in cyclosporin A (CsA) nephrotoxicity, we examined the renal effects of the selective [125I]ET-1 binding to porcine aortic membrane (ETA) receptor antagonist, BQ-123 (BQ), on CsA-treated rats. An osmotic minipump filled with BQ or its vehicle (saline), was subcutaneously implanted and animals were treated with CsA (50 mg/kg/d, i.p.) for 4 d. In both BQ- and its vehicle-treated rats, the 24-hour urine volume, urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion, urinary Ca/creatinine (Cr) and urinary NAG/Cr ratios were significantly increased compared with those before administration of CsA. In contrast, after administration of CsA, urinary Cr excretion was significantly decreased in both rat groups. Although urinary NAG excretion and the NAG/Cr ratio in the rats treated with BQ were significantly increased compared with those treated with saline, the serum Cr levels in BQ-treated rats were significantly lower than those in saline-treated rats. Urinary immunoreactive ET-1 (irET-1) excretion in all animals was significantly increased after administration of CsA. There were no significant differences in urinary irET-1 excretion in both BQ-treated and saline-treated rats with and without CsA. Expression of irET-1 was seen in the cytoplasm of renal tubules, but the degree of expression was similar in the BQ-treated and saline-treated rats on CsA. In the BQ-treated rats, small round areas with high grain densities over the glomeruli in the cortex and vesa recta bundles in the outer medulla were masked by the antagonist action of BQ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Expression of multidrug resistance gene product (P-glycoprotein) in transitional cell carcinomas of the upper urinary tract.

We assessed the expression of P-glycoprotein, the product of the multidrug resistance gene, in 107 specimens from patients with transitional cell carcinoma of the upper urinary tract, using an immunohistochemical method with a polyclonal antibody. P-glycoprotein was expressed in 28 of 107 (26%) specimens. While P-glycoprotein expression was not related to the grade or stage of these tumors, the incidence of P-glycoprotein in specimens with tumors which coexisted in renal pelvic and ureter is significantly higher than those with either renal pelvic or ureter tumor alone. In the patients with advanced upper urinary tract tumor who had adjuvant chemotherapy including at least one P-glycoprotein-transported drug (mdr regimen), overall survival of patients with P-glycoprotein-positive tumor was significantly shorter than that of patients with negative tumor. This pilot study demonstrates that P-glycoprotein can be expressed in one fourth of transitional cell carcinomas of the upper urinary tract and that P-glycoprotein expression serves as a prognostic indicator in patients with these tumors who are treated with mdr regimens.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Synthesis and antitumor activities of prodrugs of benzoylphenylureas.

Various benzoylphenylurea derivatives were synthesized as candidate prodrugs and their antitumor activities were examined in vivo against P388 leukemia. All of the prodrugs were soluble in most organic solvents and showed good antitumor activities against P388 leukemia cells in mice when dosed intraperitoneally or orally.

Animals↗