Biomedical subjects

Tsuneo Ueki

Publications and source records attributed to Tsuneo Ueki.

5 recordsLinked to original sources

PubMed2005

Circadian blood pressure rhythm is disturbed by nephrectomy.

We recently illustrated a close relationship between glomerular filtration rate and circadian rhythm of blood pressure (BP) in patients with chronic kidney disease. However, it remains undetermined from such cross-sectional findings which occurs first, the loss of kidney function or the lack of nocturnal BP fall. In the present study, we examined whether circadian rhythm of BP is affected by unilateral nephrectomy for kidney donation to clarify this important issue. Fifteen healthy subjects (4 men, 11 women; aged 33 to 65 years; mean age 55 +/- 2 years) who underwent unilateral nephrectomy for kidney donation were studied. Ambulatory BP was monitored for 24 h, while serum and urinary samples were collected to estimate creatinine clearance before and on the 8th day after nephrectomy. Then, changes in the night/day ratios of mean arterial BP were analyzed in relation to the decrease in 24-h creatinine clearance as a marker of glomerular filtration rate by nephrectomy. Creatinine clearance was reduced by 29% in average from 84 +/- 6 to 60 +/- 4 ml/min by nephrectomy, while 24-h mean arterial BP values were 91 +/- 3 and 94 +/- 4 mmHg (p=0.08) before and after nephrectomy. Although mean BP (daytime, nighttime or night/day ratio) was not altered significantly by nephrectomy, the decrease in creatinine clearance was positively correlated with the increase in the night/ day ratio of mean BP (r=0.61, p=0.017). The decrease in creatinine clearance was not correlated with changes in either 24-h, daytime or nighttime mean BP. Our results suggest that unilateral nephrectomy disturbs the circadian rhythm of BP as a function of renal dysfunction without affecting absolute levels of BP. Non-dipping of BP seems the consequence of the loss of renal function, rather than the cause.

Adult↗

PubMed2004

Total parathyroidectomy reduces elevated circulating fibroblast growth factor 23 in advanced secondary hyperparathyroidism.

BACKGROUND: Secondary hyperparathyroidism is a common complication in patients with stage 5 chronic kidney disease (CKD), accelerated by hyperphosphatemia. Fibroblast growth factor 23 (FGF-23), a phosphorus-regulating protein, has key roles in several phosphate-wasting disorders. The aim of this study is to examine the association of advanced secondary hyperparathyroidism with circulating FGF-23 levels. METHODS: Fifteen patients with marked secondary hyperparathyroidism (parathyroid hormone [PTH], 990 +/- 118 pg/mL [ng/L]) were enrolled. All underwent parathyroidectomy with forearm autotransplantation (PTX), and their FGF-23 levels were measured before and after PTX (days 1, 3, 7, and 10) by means of sandwich enzyme-linked immunosorbent assay. RESULTS: Preoperative FGF-23 levels correlated positively with phosphorus (P < 0.05), calcium-phosphorus product (Ca x P; P < 0.0005), and PTH values (P < 0.05). Serum FGF-23 levels decreased time dependently after PTX (P < 0.0005). Both serum phosphorus and Ca x P values decreased similarly after PTX ( P = 0.0001). Furthermore, FGF-23 levels days 1 and 3 correlated linearly with serum phosphorus (P < 0.05; P < 0.005, respectively) and Ca x P values (P < 0.01; P < 0.0001, respectively). CONCLUSION: FGF-23 levels correlate positively with serum phosphorus, Ca x P, and PTH values in patients with advanced secondary hyperparathyroidism. Complete ablation of progressive parathyroid glands reduces circulating FGF-23 levels, simultaneously decreasing serum phosphorus and Ca x P values. These findings suggest that hyperplastic parathyroid glands, together with hyperphosphatemia, affect abnormal FGF-23 metabolism in patients with stage 5 CKD with advanced secondary hyperparathyroidism.

Chronic Disease↗

PubMed2004

Infarction of mediastinal parathyroid gland causing spontaneous remission of secondary hyperparathyroidism.

Secondary hyperparathyroidism is a serious complication in long-term hemodialysis patients. The authors report on 2 patients on long-term hemodialysis who suffered from persistent secondary hyperparathyroidism due to missed mediastinal parathyroid gland after total parathyroidectomy with forearm autograft. Reoperation was planned. In both cases, severe hypocalcemia suddenly developed; serum parathyroid hormone (PTH) level decreased markedly after this episode. The serum calcium level increased gradually in response to administration of vitamin D and calcium carbonate, but serum PTH level remained low. A follow-up computed tomography scan showed that the formerly enlarged mediastinal parathyroid gland was markedly reduced in size. Moreover, a hot spot formerly detected by technetium 99m-MIBI (methoxy-isobutyl-isonitrile) scintigraphy in the mediastinum disappeared after this episode. The authors considered that necrosis of the enlarged ectopic parathyroid gland, probably due to infarction, resulted in hypocalcemia. To the authors' knowledge, this is the first case report of spontaneous mediastinal parathyroid autoinfarction after parathyroidectomy in hemodialysis patients.

Choristoma↗

PubMed2003

Diabetes mellitus after transplant: relationship to pretransplant glucose metabolism and tacrolimus or cyclosporine A-based therapy.

OBJECTIVE: The purpose of this study was to identify pretransplantation and posttransplantation indicators for the development of diabetes mellitus in the first 2 months after renal transplantation and to examine the influence of a cyclosporine A (CsA)-based versus a tacrolimus-based immunosuppressive regimen on these risk factors. METHODS: Key variables associated with the development of posttransplant diabetes mellitus (PTDM) in the first 2 months after transplantation were assessed in 48 patients who underwent living-related renal transplantation and who were treated with a CsA-based or a tacrolimus-based immunosuppressive regimen. The insulinogenic index (I Index) and glucose infusion rate (GIR) were measures of insulin secretion and insulin sensitivity, respectively. RESULTS: Eight patients developed PTDM. I Index (odds ratio, 0.000384) and GIR (odds ratio, 0.349) were significant risk factors for PTDM development. The cumulative steroid dose had a borderline association. PTDM developed in 4 of 28 CsA-treated patients and in 4 of 20 tacrolimus-treated patients. CsA therapy increased the mean I Index from 0.713+/-0.071 preoperatively to 1.130+/-0.140 postoperatively (P<0.01), whereas in tacrolimus-treated patients, I Index remained unchanged (1.09+/-0.264 preoperatively and 0.949+/-0.296 postoperatively; P=not significant). Age, duration of pretransplant dialysis, and body mass index did not predict PTDM development. All eight patients with PTDM had hypertension. CONCLUSIONS: Pre- and posttransplant abnormalities of insulin secretion and sensitivity are significant predictors of PTDM. Corticosteroid cumulative dose may affect the incidence of PTDM during the first 2 months after transplantation. CsA treatment increases insulin secretion in patients with a high pretransplant risk of PTDM.

Adult↗

PubMed2003

[Non-ischemic partial nephrectomy using microwave tissue coagulator].

PURPOSE: The indications and the safety of non-ischemic partial nephrectomy using a microwave tissue coagulator were studied. MATERIALS AND METHODS: Non-ischemic partial nephrectomy was performed on 17 kidneys of 16 patients using a microwave tissue coagulator. The diagnosis was renal tumor and renal stones in eleven and five patients, respectively. Renal tumors were less than 4 centimeters in diameter, while the stones were associated with a caliceal diverticulum or secondary cortical atrophy. Excision of the tumors was done via the retroperitoneal approach through an oblique lumbar incision. The needle of the microwave tissue coagulator was inserted around the tumor (stone) 10 to 20 times, and the coagulator was activated. Then the tumor (stone) was excised with a sharp knife or scissors. Patients were encouraged to walk on the first postoperative day. RESULTS: Vascular clamping was necessary in one patient to reduce bleeding. Nephrectomy was done after partial nephrectomy in one patient because it was difficult to close the urinary collecting system after it was widely exposed. Although urine leakage was seen postoperatively in two patients, it ceased spontaneously at 14 and 23 days after surgery. Postoperative complications developed in one of seven patients (14%) with protruding renal tumor, in three of five patients (60%) with non-protruding renal tumor and in two patients with renal stone. Allogenic or autologous blood transfusion was not necessary, nor was any bleeding noticed post-operatively. In one patient, atrophy of the renal parenchyma occurred gradually after surgery and function was eventually lost. However, renal function was well preserved and recurrence of the problem was not observed in the other 15 patients, excluding one who died of esophageal cancer. CONCLUSIONS: The microwave tissue coagulator is a useful surgical instrument for non-ischemic partial nephrectomy, not only in patients with renal tumors but also in patients with complicated kidney stones. However, non-protruding renal tumor in a patient with solitary kidney should be avoided for this surgery. Thermal injury to the renal parenchyma or large vessels should be avoided and urine leakage from the collecting system should be meticulously treated during the operation.

Adult↗