Katsuyuki Taguchi

Renal tissue damage induced by focused shock waves

Biological evidence of renal arterial wall damage induced by the microjet due to shock wave‐cavitation bubble interaction was demonstrated in living dog kidneys. We also intended to clarify the mechanism of renal tissue damage and the effects of different conditions of shock wave exposure (peak pressure of focused area, number of shots, exposure rate) on the renal tissue damage in comparison to stone disintegration.Disruption of arterial wall was the most remarkable histological change in the focused area of the kidneys. This lesion appeared as if the wall had been punctured by a needle. Large hematoma formation in the renal parenchym, and interstitial hemorrhage seemed to be the results of the arterial lesion. This arterial disorder also led to ischemic necrosis of the tubules surrounding the hematoma. Micro‐angiographic examination of extracted kidneys also proved such arterial puncture lesions and ischemic lesions.The number of shots required for model stone disintegration was not inversely proportiona...

Effects of parathyroid hormone on urinary excretion of N-acetyl-β-D-glucosaminidase in idiopathic hypoparathyroidism and pseudohypoparathyroidism

SummaryN-acetyl-β-D-glucosaminidase(NAG) is a lysosomal enzyme predominantly located in renal proximal tubules. In idiopathic hypoparathyroidism(IHP), 100 Units of human PTH(1–34) increased urinary excretion of NAG from 0.029±0.027 to 0.173±0.035 U/1GF (p<0.05) in two patients before treatment and from 0.025±0.004 to 0.189±0.092U/1GF (p<0.02) in four patients during treatment with active vitamin D3 (1,25(OH)2D3 or 1αOHD3). In pseudohypoparathyroidism(PHP), PTH did not significantly increase the urinary excretion of NAG in one patient with before treatment (0.048 to 0.025 U/1GF) and four patients during treatment with active vitamin D3 (0.018±0.008 to 0.036±0.015 U/1GF). Increase in urinary excretion of NAG after injection of PTH may be a new indicator of renal effect of PTH.

Acoustic cavitation bubbles in the kidney induced by focused shock waves in extracorporeal shock wave lithotripsy (ESWL)

On an ultrasonic imaging system a hyperechoic region was observed in a focal area of fucused shock waves in the dog kidney. This study was performed to learn whether cavitation bubbles are responsible for this hyperechoic region.The ultrasonic images in water of varying temperatures were not markedly different. In the flowing stream of distilled water, the stream was demonstrated as a hyperechoic region only with a mixture of air bubbles. Streams of 5%–50% glucose solutions were also demonstrated as a hyperechoic region. However, such concentration changes in living tissue, as well as thermal changes, are hardly thought to be induced.The holographic interferometry showed that the cavitation bubbles remained for more than 500 msec. in the focal area in water. This finding indicate that the bubble can remain for longer period than previously supposed.These results support the contentions that cavitation bubbles are responsible for the hyperechoic region in the kidney in situ.

Effects of focused shock waves on biological tissues: Cavitation in the prefocal region and the fluid flow in the focal region

In order to elucidate the mechanism of shock wave injury in biological tissues, the mechanical damage of aluminum foils and the hyperechoic region, in the focal zone were studied. The shock waves were produced by a specially designed piezo-ceramic (overhead and water-bag type) generator. For focus localization an ultrasonic sector probe was used. On aluminum foils numerous pits were observed circumferentially around the central major deformity. The pits were formed not only in the focal region but also in the pre-focal region. The hyperechoic region, which appeared as a cloudy area on an ultrasound screen in the focal region, moved and disappeared after more than 5 sec. The numerical simulation indicated that the maximum flow speed reached 30 meter per second, and the direction of the flow was both axial and radial.

Pure Stage I Seminoma with an Elevated hCG of 25,265 mIU/ml: A Case Report.

We report a histologically pure stage 1 seminoma with an elevated human chorionic gonadotropin (hCG). A 38 year-old man was referred for the evaluation of the left testicular swelling. He showed an elevated serum hCG level of 25,265 mIU/ml with normal a fetoprotein and lactate dehydrogenase. Imaging showed heterogeneous tumor without any metastatic lesions. We conducted 4 courses of chemotherapy before detecting hCG nadir. The final pathological report showed pure seminoma with syncytiotrophoblastic cells but no choriocarcinoma components. The patient remains disease free until present time. The case raised several questions regarding diagnosis and treatment strategy for bulky testicular seminoma.