Tomonori Miyazato

EVIDENCE FOR INVOLVEMENT OF THE SUBCOERULEUS NUCLEUS AND NUCLEUS RAPHE MAGNUS IN URINE STORAGE AND PENILE ERECTION IN DECEREBRATE RATS

PURPOSE Micturition and male sexual activity require the lower urinary tract to function. During the sexual act, micturition must be inhibited and urine stored in the bladder. We studied the role of the brainstem in relation to both micturition/urine storage and penile erection in rats. MATERIALS AND METHODS Wire electrodes were placed on the dorsal nerve of the penis and microelectrodes for stimulation were introduced into the brainstem in decerebrate male rats. Electrical stimulation was used to locate optimally responding sites by monitoring the isovolumetric intravesical pressure and intracavernous pressure. RESULTS Electrical stimulation of the dorsal nerve of the penis, the subcoeruleus nucleus in the rostral pons, and the nucleus raphe magnus in the caudal pons increased intracavernous pressure, but inhibited rhythmic bladder contractions. Electrical stimulation of Barringtons nucleus (the pontine micturition center in the rat) in the rostral pons induced bladder contraction. Stimulation of the pontine reticular formation did not increase intracavernous pressure. Acute transection of the thoracic spinal cord eliminated rhythmic bladder contractions, but gave rise to sporadic increments of intracavernous pressure. CONCLUSIONS This electrophysiological study demonstrated that the subcoeruleus nucleus and nucleus raphe magnus are involved in both urine storage and penile erection, and that their physiological functions are reciprocally controlled; so that erection leads to inhibition of micturition.

Oxalate and urinary stones.

A bstractCalcium oxalate is a major component of renal stones, and its urinary concentration plays an important role in stone formation. Even a small increase in urinary oxalate has a significant impact on calcium oxalate saturation. Although primary hyperoxaluria is relatively uncommon, patients with calcium oxalate stones have some degree of hyperoxaluria. To understand the underlying causes of such hyperoxaluria, the processes of oxalate synthesis and excretion must be clarified. This article focuses on the determination of oxalate, calculation of its saturation, and the hyperoxaluric syndromes with special reference to metabolic precursors of oxalate, including ascorbic acid, glyoxylate, and glycolate.

Glyoxylate determination in rat urine by capillary electrophoresis

Abstract Oxalate is important in the study of renal stone formation and is derived from the endogenous metabolism of glyoxylate. The aim of this study was to determine urinary glyoxylate levels by capillary electrophoresis (CE). Urine specimens were obtained from 25 male Wistar rats (16 rats intravenously injected with 10 mg or 20 mg glyoxylate and nine controls) by bladder puncture 1 h after administration of glyoxylate or saline. Urinary glyoxylate was measured by CE using an electrolyte composed of 5 mmol/L pyridinedicarboxylic acid and 0.5 mmol/L cetyltrimethylammonium bromide (pH 5.6 and 11.0). The mean ± SD urinary glyoxylate concentration was 43.1 ± 14.7 μmol/L in control rats, 722.8 ± 165.5 μmol/L in rats given 10 mg of glyoxylate and 1290.0 ± 470.8 μmol/L in rats given 20 mg of glyoxylate. The mean ± SD recovery after spiking 675.7 μmol/L of glyoxylate into 16 urine specimens was 98.82 ± 12.81%. When the reproducibility of urinary glyoxylate determination was assessed, the intra‐assay coefficient of variation (CV) ranged from 1.38 to 2.59% and the inter‐assay CV ranged from 2.94 to 6.69%. Capillary electrophoresis enables sensitive and reproducible determination of urinary glyoxylate levels in rats. This method appears to be suitable for laboratory use and has the advantage of determining glyoxylate and several other urinary anions simultaneously.

Pelvic congestion syndrome caused by inferior vena cava reflux

We present a female patient who had pelvic congestion syndrome caused by inferior vena cava reflux associated with tricuspid regurgitation, but without other symptoms or signs related to her tricuspid regurgitation. Bladder pumping therapy was effective in improving her symptoms.

Effect of Injury to the Dorsal Funiculus of the Thoracic Spinal Cord on Micturition in Decerebrate and Freely-Moving Cats

Bladder sensation is transmitted both via the spinothalamic tract in the lateral funiculus and the dorsal system in the dorsal funiculus. We transected the dorsal funiculus in 10 female cats to clarify the functional roles of these two ascending pathways. The dorsal funiculus was transected at T10 in 5 decerebrate and 5 freely-moving cats, and micturition parameters were compared before and after transection. Transection of the dorsal funiculus did not affect any of the parameters of reflex micturition in the 5 decerebrate cats. Within 1 week after transection, 4 of the 5 freely-moving cats used the normal micturition posture, but the remaining one performed micturition in a prone position as if she had lost micturition sensation. All 5 cats urinated with a normal micturition posture by 2 weeks after transection. The mean single voided volume was decreased transiently up to 1 week, but returned to normal by 2 weeks after transection. None of the 5 cats had any residual urine before and after transection. Both the ascending and descending limbs of the micturition reflex pass through the lateral funiculus. Bladder sensation is transmitted both via the spinothalamic tract coursing in the lateral funiculus and the dorsal system in the dorsal funiculus. The dorsal system may play a major role in the transmission of bladder sensation to the cerebral cortex, but may not be essential.

An alternative procedure for the creation of an ileal conduit in patients undergoing pelvic exenteration : dextrotransmesenteric location

Abstract Ileal conduits have long been accepted as a standard method for urinary diversion, but conventional ileal conduits are not always suitable for patients whose ureters are for the greater part compromised by neoplasm or preoperative irradiation, resulting in a shortening of the ureters. Bowel migration into the large cavity, which develops after pelvic organ removal, appears to cause tension on the ureteroileal anastomotic site. Dextrotransmesenteric placement of an ileal conduit may provide easy access to the shortened ureters without exerting pressure on the anastomosis. We employed this procedure in seven patients undergoing pelvic exenteration with relatively minimal morbidity.