Biomedical subjects

Tatsuya Akiyama

Publications and source records attributed to Tatsuya Akiyama.

2 recordsLinked to original sources

PubMed2006

Decrease in nocturnal urinary levels of arginine vasopressin in patients with nocturnal polyuria.

OBJECTIVES: To elucidate whether heart function and endocrine levels of arginine vasopressin (AVP) or solute diuresis is associated with the nocturnal voided volume, and whether the urinary AVP could be a parameter for screening for nocturnal polyuria caused by AVP insufficiency. METHODS: A total of 50 patients were enrolled in this study. The blood and urine samples were obtained every 6 hours at 6 pm, 12 am, 6 am, and 12 pm. Atrial natriuretic peptide and brain natriuretic peptide were measured at admission. All voided urine samples were collected every 6 hours for examination. The evaluation items were AVP, osmolarity, sodium, potassium, chloride, and creatinine in blood and urine. RESULTS: The patients were classified into a group with nocturnal polyuria (n = 21) and a group without nocturnal polyuria (n = 25). There was no significant difference in atrial natriuretic peptide, brain natriuretic peptide, electrolytes in blood and urine, and plasma AVP of each sample between the two groups, but urinary AVP/urinary creatinine and urine osmolarity at 12 am and 6 am in the group with nocturnal polyuria were significantly lower than those in the group without nocturnal polyuria. The nocturnal voided volume correlated with urinary AVP/urinary creatinine level in the urine samples obtained at 12 am and 6 am. CONCLUSIONS: The present data have demonstrated that the significant decrease in urinary AVP/urinary creatinine level at 6 am may contribute to the increased nocturnal voided volume followed by nocturia and that the circadian rhythm disorder of AVP can be predicted by a noninvasive test measuring urinary AVP/urinary creatinine in the urine voided early in the morning.

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PubMed2002

Comparison of parameters to determine the cause of urinary disturbance in men with prostate volume less than 20 milliliters.

BACKGROUND: A pressure-flow study, although a slightly invasive procedure, can evaluate bladder outlet obstruction and detrusor contractility. This study was conducted in men with a non-enlarged prostate to determine the cause of urinary disturbance by less invasive examinations that might eventually replace pressure-flow study. METHODS: Thirty-six men with lower urinary tract symptoms were enrolled. Their prostate volume, estimated by transrectal ultrasonography, was less than 20 mL. All patients were examined using pressure-flow study, free-flowmetry, transrectal ultrasonography, prostate specific antigen and an interview using the International Prostate Symptom Score and Quality of Life Index. With determination of the cause for urinary disturbance, parameters that correlated with outflow obstruction or impaired detrusor contractility were sought. RESULTS: Twenty-one (60%) of the 36 men were judged as having outflow obstruction, and 16 of these 21 men had normal detrusor function. Impaired detrusor contractility was observed in 17 men. Only three of these 17 men had no outflow obstruction. Four patients had an unstable bladder. All these four had normal detrusor contractility, but had outflow obstruction. Among the parameters examined, only the maximum flow rate in a flow metrogram (Qmax) correlated significantly with the degree of outflow obstruction (P = 0.04). The positive predictive value of Qmax for outflow obstruction was 65% at a flow rate of less than 10 mL/s, and 100% at that of less than 5 mL/s. No parameter correlated with detrusor contractility. CONCLUSION: The only parameter that was a clear indicator of outflow obstruction was Qmax. Other indicators of detrusor contractility should be sought.

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