Biomedical subjects

T Umekawa

Publications and source records attributed to T Umekawa.

At least 109 records · Page 6Linked to original sources

PubMed1992

Renal damages after extracorporeal shock wave lithotripsy evaluated by Gd-DTPA-enhanced dynamic magnetic resonance imaging.

Renal damages after extracorporeal shock wave lithotripsy (ESWL) were evaluated by magnetic resonance imaging (MRI) including Gd-DTPA-enhanced dynamic MRI in 37 patients with renal stone by spin echo methods (T1 and T2-weighted scan) and small tip angle gradient echo method (T2-weighted scan). Sixty-eight percent of the patients had changes in the MRI findings after ESWL. The frequently observed findings were perirenal fluid collection (38%), loss of corticomedullary junction (35%), and increased signal intensity of muscle and other adjacent tissue (34%). Preoperative Gd-DTPA-enhanced dynamic MRI showed low intensity band which suggests Gd-DTPA secretion from the glomerulus into the renal tubulus. In all cases the low intensity band became unclear after ESWL because of renal contusion due to ESWL. MRI, including Gd-DTPA-enhanced dynamic MRI, is considered to be a good procedure for evaluation of renal damages due to ESWL.

Contrast Media↗

PubMed1992

Effects of endothelin-1 on antidiuresis and norepinephrine overflow induced by stimulation of renal nerves in anesthetized dogs.

The effects of endothelin-1 (ET-1) on renal function and norepinephrine (NE) overflow induced by renal nerve stimulation (RNS) were examined in anesthetized dogs, and comparisons were made with effects of Bay K 8644, a calcium channel agonist. RNS at a low frequency (0.5-2.0 Hz) produced significant decreases in urine flow and urinary excretion of sodium and increased NE secretion rates without influencing renal hemodynamics. RNS, at a high frequency of 2.5-5.0 Hz which diminishes renal hemodynamics, affected urine formation and NE secretion rate more potently than did low-frequency RNS. Intrarenal arterial infusion of ET-1 (1.0 ng/kg/min) decreased the baseline level of renal blood flow by 25% and that of urinary excretion of sodium by 54-69% but did not alter basal levels of NE secretion rate. During ET-1 infusion, low-frequency RNS-induced antidiuresis was observed to an extent similar to that seen without ET-1 infusion, whereas increase in NE secretion rate elicited by RNS was significantly inhibited by ET-1 infusion (45-65% of the values without ET-1 infusion). In addition, in the case of high-frequency RNS, ET-1 did not affect antidiuretic responses but did inhibit the increase in NE secretion rate by approximately 55%. In contrast, alterations in renal excretory responses and NE secretion rate elicited by RNS were not influenced by Bay K 8644 infusion (1.0 micrograms/kg/min), a dose that decreased renal blood flow to the same degree as did 1.0 ng/kg/min of ET-1.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1991

Characteristics and usage of different ureteral stent catheters.

Presuming that complications associated with ureteral stenting vary in type and occurrence depending on the material and cross-section of the stent, six types of stents immersed in 48 different preparations of artificial urine for 1 month to observe surface changes with a scanning electron microscope. As a result, there was less encrustation on the silicone material compared with other material types, probably due to the smoothness of the surface. This may be related with higher frequency of spontaneous removal or migration to the bladder of this catheter type. Because silicone catheters have softer and thicker walls with a narrow lumen, they may be appropriate for long-term stenting, but not for urinary drainage. In alkaline bacteriuria, struvite encrustation was observed on all stents. This reaction was especially intense with Towers peripheral stents, which had most irregular and uneven surfaces. In aseptic alkaline urine, calcium phosphate crystals partly covered with proteinaceous debris were noted on catheter surfaces. Although in some patients encrustation of uric acid occurred in the bladder portion of the stents, there was no uric acid encrustation in this experimental study.

Crystallization↗

PubMed1991

[The anticancer effects of high energy shock waves on rat bladder cancer induced by BBN].

The in vivo anticancer effects of high energy shock waves (HESW), on bladder cancer induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), were studied in the rat using the Siemens lithotriptor (Lithostar). There was no significant difference in the anticancer effects in delaying tumor growth, measured as the whole bladder weight including the weight of the cancer, between the groups with and without exposure to HESW. However, light microscopic examination revealed extensive submucosal bleeding and exfoliation of mucosa, and electron microscopic examination revealed degeneration of pleomorphic microvilli, swelling of mitochondria, and destruction of mitochondrial cristae in the cancer cells in bladders exposed to HESW. Flow cytometric determination of DNA content in the cancer cells exposed to HESW indicated a selective diminution of cells in the G2 and M phases and an increase of cells in the G0 and G1 phases of the cell cycle. While the mechanism of HESW-induced anticancer effect could not be determined on the basis of this study, these changes in the morphology and the cell cycle of cancer cells induced by HESW exposure suggest some kind of biological effects following exposure to HESW. It is expected that HESW be an effective method for the treatment of human cancer in combination with chemotherapy and radiation.

Animals↗

PubMed1991

[Studies on renal damages after extracorporeal shock wave lithotripsy using Gd-DTPA-enhanced dynamic MRI].

Renal damages after ESWL treatment were examined by Gd-DTPA enhanced dynamic MRI. Gd-DTPA was used as the contrast medium and fast magnetic resonance imaging with suspended respiration using the flip angle of 20 degrees and gradient echo technique at 0.5 Tesla was used for photographing. In normal kidneys, a low intensity band was observed with the passage of Gd-DTPA through the kidney from 1 to 2 minutes after the injection. In patients who underwent ESWL treatment, however, the low intensity band which was observed before ESWL treatment became partly obscure after ESWL treatment. Furthermore, these find changes in the renal parenchyma could not be fully detected by usual MRI which does not use Gd-DTPA. Gd-DTPA enhanced dynamic MRI was considered to be effective for finding the limited dose of shock waves for ESWL treatment.

Adult↗

PubMed1991

[Preparation of a standard diet for out-patients in the study of lithogenesis].

With the development of extracorporeal shock wave lithotripsy treatment, the duration of hospitalization for stone patients fortunately has become shorter. However, a detailed analysis of lithogenesis is not possible during such patients' short hospital stays. We prepared a standard diet to be eaten at home for investigation of lithogenesis at the out-patient clinic. This diet was nutritionally well-balanced and contained the following: energy: 2000 Kcal, total protein: 70-75 g, animal protein: 30-35 g, carbohydrate: 510 g, fat and oil: 50-60 g, calcium: 600-630 mg and magnesium: 320 mg. The urine of 24 male patients with stones on a free diet and the same patients after 3 days on the standard diet was analyzed for urea-nitrogen, uric acid, sodium, calcium, phosphorus, magnesium, citric acid and oxalic acid. The results were compared with those in 17 healthy male subjects who were eating the standard diet (controls). It was found that 66% of hypercalciuria (greater than = 300 mg/day) on a free diet became normocalciuria on the standard diet. The hypercalciuria was therefore thought to be of dietary origin. Moreover, urinary excretion of urea nitrogen, uric acid, sodium and phosphorus by patients remarkably decreased after 3 days on the standard diet, which was not different from that of controls. These results suggest that the standard diet at home is useful in the screening of hypercalciuria and also quite adequate for patients with stones.

Adult↗

PubMed1991

[AIH in male infertility due to retrograde ejaculation after retroperitoneal lymph node dissection].

A patient with testicular cancer (non-seminoma, stage IIB) who had undergone resection for primary disease and retroperitoneal lymph node dissection as well as chemotherapy and radiotherapy 6 years before developed iatrogenic retrograde ejaculation. The infertility was treated by oral medications, including herbal medicine and injections of a hormone preparation as well as artificial insemination of husband (AIH). After 24 sessions of AIH for 4 years, his spouse gave birth to a healthy baby girl. We believe that for patients with iatrogenic retrograde ejaculation AIH is an effective method of increasing fertility to be employed more often.

Adult↗

PubMed1991

[Studies on calcium oxalate crystal formation in urolithiasis. Multi-regressive analysis of urinary CaOx crystalline volumes and the effects of urinary various substances on CaOx crystal formation].

Because human urine contains various substances which can affect each other, it is quite difficult to clarify the mechanism of formation of calcium oxalate (CaOx) crystal in urine. The authors recently determined CaOx crystalline content and the concentrations of other substances in urine specimens from patients with urolithiasis and healthy volunteers, and subjected the data to multi-regressive analysis for the purpose of assessing the effect of these urinary substances on CaOx crystal formation. 1. In analysis of urine from patients with urolithiasis, the partial correlation coefficients of CaOx crystal formation with oxalic acid, sodium, calcium, uric acid magnesium were 0.67, 0.28, 0.18, and -0.10, respectively. The formula of regression was as follows: Amount of CaOx crystal (X 10(6) microns3/ml) = 3.59 X 10(-2) Ox (mM/L) + 4.72 X 10(-3) Ca (mM/L) + 4.52 X 10(-3) Na (mM/L) + 2.51 X 10(-4) UA (mM/L) -2.39 X 10(-2) Mg (mM/L) -1.65. The multiple correlation coefficient was 0.759. Thus, in patients with urolithiasis, urinary crystal formation was most dependent on the oxalic acid level, sodium, calcium, and uric acid were found to promote crystal formation, while magnesium to suppress it. 2. In analysis of urine from healthy volunteers, the partial correlation coefficients of CaOx crystal formation with oxalic acid and inorganic phosphorus were 0.51 and -0.24, respectively. The formula of regression was as follows: Amount of CaOx crystal (X 10(6) microns3/ml) = 1.91 X 10(-2) Ox (mM/L) -3.43 X 10(-4) P (mM/L) +0.29 The multiple correlation coefficient was 0.525.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗

PubMed1991

[The effectiveness of prophylactic dietary treatment in renal stones].

By following individual dietary guidelines which were established from analysis of the dietary intake and habits of male renal stone patients, the stone recurrence rate in 75 male calcium stone patients who had only received individual dietary instruction decreased markedly, as compared with that in 114 male calcium stone patients who had not received such instructions. Among 75 patients, recurrence was noted in 6 normocalciuric recurrent stone patients and 1 normocalciuric single stone patient during the period of outpatient visits. Investigation of the daily consumption of various nutrients and urinary excretion revealed no differences among the 6 normocalciuric recurrent stone patients, hypercalciuric recurrent stone patients, hypercalciuric single stone patients and normocalciuric single stone patients. Our findings suggest that the high recurrence rate in the normocalciuric recurrent stone patients is associated with stone lithogenic factors, such as heredity and anatomy, that could not be controlled by the daily treatment in this group.

Adolescent↗

PubMed1991

[Indications for surgical treatment of secondary hyperparathyroidism].

From 1978 to 1990 subtotal parathyroidectomy was carried out on 41 patients for secondary hyperparathyroidism. The indications for parathyroidectomy and suitable operative time, especially in the point of view of renal osteodystrophy are discussed. Serum ALP and PTH level and the presence of generalized fibrous osteitis were good indicators for parathyroidectomy. Furthermore, 99mTc-Pyrophosphate bone scintigraphy and Dual Photon Absorptiometry were proved to be valuable for patient selection for parathyroidectomy. Parathyroidectomy for patients in whom 99mTc-pyrophosphate bone uptake is diminished or patients in whom bone mineral contents are dramatically decreased must be carefully performed.

Absorptiometry, Photon↗

PubMed1990

Relationship of plasma and urine composition to recurrence of calcium urinary stones in patients on drug therapy.

Factors relating alterations in plasma and urine composition to recurrence of urinary stones during drug therapy were investigated by using a multiple regression analysis technique. These factors were influenced not only by the efficacy of the drugs but also by other factors (plasma or urinary constituents and overall health of the patients, etc.). In order to study the effect of drug therapy or other treatment on the alteration of plasma and urine constituents, multiple regression analysis is more appropriate than Student's paired t-test which has been used by some workers. These two analytical methods yield different results even if used on the same data.

Adult↗

PubMed1990

Calcium oxalate crystal formation in patients with hyperparathyroidism and hyperthyroidism and related metabolic disturbances.

The crystallization of calcium oxalate in the urine of patients with hyperparathyroidism and hyperthyroidism was studied using a mixed suspension mixed product removal (MSMPR) system. In addition, calcium metabolism in hyperthyroidism and its relationship to urolithiasis was investigated. The urines from all the three groups (normal subjects, hyperparathyroid and hyperthyroid patients) showed reduced nucleation rates and increased growth rates in comparison with the control synthetic urine. The nucleation rate was not significantly different between the three human urine groups, while the growth rate was significantly higher in the hyperparathyroid group compared to the normal and hyperthyroid groups. Crystal volume (suspension density) in the hyperparathyroid group was approximately twice that in the other two groups. Serum and ionized calcium levels in hyperparathyroid patients were higher than in normal subjects, while hyperthyroid patients had levels only slightly higher than those in normal subjects. The hyperparathyroid and hyperthyroid groups differed significantly from the normal group in urinary calcium excretion. These two groups also showed significantly higher levels of serum alkaline phosphatase and urinary hydroxyproline than did the normal group. Although hyperthyroid patients have a calcium metabolism similar to hyperparathyroid patients, the incidence of urolithiasis is no different between hyperthyroid and normal subjects. The results of both crystallization and calcium metabolism in hyperparathyroid patients were not significantly different between those with and without urolithiasis. The result of crystallization was also not significantly different between hyperparathyroid patients with and without hypercalciuria. This study suggests that hypercalciuria alone does not produce urinary stones and that urine from hyperparathyroid patients may contain promotors of calcium oxalate crystallization and calcium stone formation.

Calcium Oxalate↗

PubMed1990

Clinical effects of prophylactic dietary treatment on renal stones.

From the investigation of the dietary intake and habits of male Japanese renal stone patients we established several general guidelines. Fluid intake should be increased, especially after dinner. Unbalanced diets should be corrected and avoided (the diet should include different types of food, with vegetables being eaten at every meal and an excessive intake of meat should also be avoided). Three meals a day should be eaten and an excessive intake at dinner should be avoided. The interval from dinner until retiring should be extended. By following these individual dietary guidelines the stone recurrence rate in 199 male calcium stone patients who had received individual dietary instruction decreased remarkably compared to that in male calcium stone patients who had not received individual dietary instruction, not only during the period of outpatient visits but also after outpatient visits were discontinued. From these results we conclude that individual dietary management should be the primary measure for the prophylaxis of renal stone disease in Japan.

Adult↗

PubMed1990

Dietary intake and habits of Japanese renal stone patients.

The daily consumption of various nutrients as well as the daily habits of 241 male stone patients were investigated. Hypercalciuric (300 mg. or more per day) calcium stone patients ingested much more total protein, fats, oils and calcium than normocalciuric calcium stone patients, and uric acid stone patients ingested much more total and animal protein, and carbohydrates than calcium stone patients. However, the amount of ingested calcium by the patients (470 mg.) was similar to that of age-matched healthy male subjects (476 mg.) and did not reach the level of the daily nutritive requirements (600 mg.). The patients ingested large amounts of nutrients, especially animal protein, during the evening meal. From these results it was believed that synthetic dietary management, including not only ingesting various amounts of nutrients but also changing dietary habits, is necessary for the prophylaxis of renal stones.

Adult↗

PubMed1990

Inhibitory effect of glutamic acid and aspartic acid on calcium oxalate crystal formation.

The effects of Glu and Asp on calcium stone formation was evaluated in three experiments. Studies using mixed suspension, mixed product removal crystallization and scanning electron microscopy showed that Glu and Asp inhibited the nucleation rate, growth rate and suspension density (crystal mass produced) in proportion to the concentration. The main amino acids in calcium oxalate stones and calcium phosphate stones were Glu and Asp. However, the main amino acids in uric acid stones were glycine and urea, and there were no specific amino acids in struvite stones. The activity of urinary GOT and GPT, which convert Asp and alanine, respectively, to Glu in normal subjects was significantly greater than in calcium stone formation.

Aspartic Acid↗

PubMed1990

[Clinical studies on thirty-two cases of childhood urolithiasis].

We evaluated 32 patients with urinary calculi under 16 years of age over the past 14 years since the founding of the Department of Urology, Kinki University School of Medicine. They comprised 0.8% of the total urolithiasis patients. They consisted of 18 boys and 14 girls with a male-to-female ratio of 1.29. The average age was 8.7 years for boys and 10.4 years for girls without any marked peak. The most frequently chief complaint was hematuria which was present in 15 cases (47%). Although pyuria was seen in seven cases (22%), urinary bacterial culture was positive only in 5. The underlying diseases could be diagnosed in 13 cases (41%), of which eight cases (62%) developed metabolic disorder. The sites of calculi were determined in 29 cases (91%), of which 28 had stones in the upper urinary tract. Surgical treatment was performed on 16 cases in 17 sessions. Ureterolithotomy was done in as many as five cases, followed by pyeloplasty in four cases. Nephrectomy was performed in only one case. There was only one case which had been treated with extracorporeal shock-wave lithotripsy (ESWL). The composition of calculi was found in 21 cases (66%), the majority or 13 cases (57%) of which had calcium-containing stones. Nevertheless, there was no case of hypercalciuria. When compared to the previous reports in Japan, it was worthy of note that calculi in the upper urinary tract and calcium-containing stones had higher incidences. It is expected that more patients will be treated with ESWL in the future.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

[Urolithiasis due to renal tubular acidosis associated with Sjögren's syndrome].

We encountered 4 patients with urolithiasis due to renal tubular acidosis (RTA) associated with Sjögren's syndrome. Laboratory results about RTA in 4 patients with Sjögrenhs syndrome were not significantly different from those in patients who suffered from urolithiasis due to RTA without Sjögren's syndrome. The incidence of urolitiasis in these cases was suspected to be higher than that in RTA patients without Sjögren's syndrome, because all 4 patients in this study had urolithiasis. When we examine patients with bilateral and multiple urolithiasis, particularly in middle-aged women, we should bear in mind that RTA and Sjögren's syndrome may exist in the background.

Acidosis, Renal Tubular↗

PubMed1990

[Calcium urolithiasis and bone change].

Bone mineral contents of calcium urolithiasis patients (105 males and 52 females) were measured by the microdensitometry (MD) method, and the patients were divided into the MD normal group and the MD abnormal group. The patients were also divided into the group (21 males and 3 females) treated with thiazides for 1 year or more and the nontreated group to examine various factors in blood and urine. [Nontreated group] The rate of MD abnormality was higher in younger males. The rate tended to increase with age in females. Alkaline phosphatase values were significantly higher in MD abnormal group males than in MD normal group males. Urinary calcium excretion and PTH values were significantly higher in MD abnormal group females than in MD normal group females. Comparison of hypercalciuria and normocalciuria revealed no significant difference between the MD normal rate and the MD abnormal rate. Comparison of single of stone formers and recurrent stone formers also revealed no significant difference between the MD normal rate and the MD abnormal rate. [Treated group] PTH and alkaline phosphatase values were significantly higher in the treated group than in the nontreated group. Alkaline phosphatase values were significantly higher in the MD abnormal group. From the viewpoint of stone recurrence prevention, the monitoring of bones where the majority of calcium in the body is present is considered important besides behavior of calcium in blood and urine.

Absorptiometry, Photon↗