PubMed Health⌕ Search

Biomedical subjects

Masahiko Nakamoto

Publications and source records attributed to Masahiko Nakamoto.

14 recordsLinked to original sources
PubMed2006

Early estimation of high peritoneal permeability can predict poor prognosis for technique survival in patients on peritoneal dialysis.

At the beginning of continuous ambulatory peritoneal dialysis (CAPD), different patients exhibit large differences in peritoneal permeability. To determine if early estimation of peritoneal permeability can predict the prognosis of CAPD, we used data from a personal dialysis capacity (PDC) study group in Japan to investigate patient and technique survival rates. Based on the data from a previously reported, prospective multicenter study encompassing eight dialysis centers in Japan (Am J Kidney Dis 2002; 40:1045-54), we recalculated patient and technique survival data. We reviewed the records of 139 patients newly initiated on CAPD from January 1995 to December 1999. Peritoneal permeability was estimated by PDC test within the first year after initiation. We divided the patients into paired groups according to several peritoneal permeability variables as calculated by the PDC test (area, plasma loss, and peritoneal creatinine clearance), and we compared patient and technique survival rate between the groups. The mean age of the patients was 49.6 years +/- 14.9 years (standard deviation). The mean pore area of peritoneum was 19,936 +/- 8383 cm/1.73 m2. Estimation of patient survival by the Kaplan-Meier method showed 94.2%, 88.4%, 84.1%, and 79.7% at 1, 2, 3, and 5 years respectively. Estimated technique survival (including death as an endpoint) by the Kaplan-Meier method showed 90.6%, 76.8%, 67.4%, and 54.3% at 1, 2, 3, and 5 years respectively. In the high peritoneal permeability group (high area and high plasma loss), the technique survival at 5 years was significantly lower than in the low peritoneal permeability group [area: 55.9% (high) vs. 72.7% (low), p = 0.0459; plasma loss: 43.3% (high) vs. 62.8% (low), p = 0.0197). We observed no significant difference in patient survival between the high and low peritoneal permeability patients. In the high peritoneal creatinine clearance group, patient and technique survival were both significantly lower than in the high peritoneal creatinine clearance group. Patients with high peritoneal permeability as calculated by the PDC test at the start of PD had a poor prognosis for technique and patient survival on CAPD. We conclude that early estimation of high peritoneal permeability can predict poor outcome for patients on CAPD.

Creatinine↗
PubMed2005

Three-dimensional ultrasound imaging of breast cancer by a real-time intraoperative navigation system.

BACKGROUND: In order to achieve a good cosmetic result without increasing the risk of ipsilateral breast cancer recurrence after breast conserving surgery, it is very important to minimize the resection volume of the breast without compromising the negativity of the surgical margin. For this purpose, it is necessary to obtain precise information on tumor extension. We therefore developed a three-dimensional (3-D) ultrasound navigation system for breast cancer surgery, which can be performed in the operating room just before surgery. METHODS: We obtained 3-D breast tumor images by the 3-D ultrasound navigation system in 40 patients with primary breast cancer (stage 0-II) who underwent mastectomy or breast conserving surgery. The tumor size was measured in a coronal view of the 3-D tumor image and compared with the tumor size obtained from a pathological map of the tumor extension. RESULTS: We obtained 3-D tumor images in 38 patients (success rate=95%). The tumor size in the images showed a very strong correlation with the pathological tumor size (r=0.898). The difference in tumor size between the 3-D images and pathology was less than 1 cm in 29 tumors (76.3%) and less than 2 cm in 36 (94.7%). On the other hand, the difference in tumor size between palpation and pathology was less than 1 cm in 19 out of 38 tumors (50.0%) and less than 2 cm in 29 tumors (76.3%). The absolute difference between the 3-D images and pathology was significantly less than that between palpation and pathology (p=0.0197). CONCLUSIONS: Our 3-D ultrasound navigation system is useful in visualizing breast tumor extension and is more accurate than palpation. The system is expected to be helpful in deciding on the appropriate surgical margin in breast cancer surgery, resulting in a better cosmetic outcome without increasing the risk of surgical margin positivity.

Adult↗
PubMed2005

[Characteristics of the patients who received parathyroidectomy within 5 years after the initiation of hemodialysis].

Thirteen patients, who received parathyroidectomy within 5 years after the initiation of hemodialysis, were discussed on their clinical characteristics and their prognoses. 204 patients received the first parathyroidectomy due to secondary hyperparathyroidism in our department, 13 of which were selected on dialysis duration. 9 patients were female and origin of CRF were analgesics-induced interstitial nephritis in 2 and prune-belly syndrome in 1. There were 2 patients who suffered from renal disease more than 30 years. Concomitant primary hyperparathyroidism was suspected in 1 case. In all cases, PTx achieved adequate control of 2HPT after the operation.

Adult↗
PubMed2005

[Effects of raloxifene on bone biomarkers in postmenopausal women on maintenance haemodialysis].

Postmenopausal women on maintenance haemodialysis (MHD) has considerably higher risk of bone fracture than general population with combination of postmenopausal osteoporosis and renal osteodystrophy. However, the treatment of osteoporosis on MHD has not been established. Evidence indicates raloxifene (RLX), a selective estrogen receptor modulator, is effective for a protection of bone fracture without increasing of breast cancer and endometrial cancer. We hereby report short-term use experience of RLX for the postmenopausal MHD patients. Fifteen postmenopausal MHD patients with less than 80% of YAM bone density in DEXA administrated 60 mg RLX on every HD days (3 days/week). Serum NTX level significantly decreased after 6 months (180 +/- 18 vs. 95 +/- 12 nmol/BCE/L, p< 0.05), however, i-PTH did not have the significant difference. (115 +/- 23 vs. 157 +/- 29 pg/mL). RLX is effective for bone biomarker improvement in postmenopausal MHD patients. Further evaluation for the effectiveness and safety of RLX is necessary in the long term.

Aged↗
PubMed2004

Intussusception of the appendix that reduced spontaneously during follow-up in a patient on hemodialysis therapy.

A 63-year-old man on long-term hemodialysis therapy was hospitalized due to right lower abdominal pain. CT scan demonstrated a multiple concentric structure in the ileocecal region. Colonoscopy showed a polyp-like tumor arising from the expected location of the appendix, with a dimple at the top. Barium enema study revealed a submucosal tumor-like filling defect in the cecum with non-filling of the appendix. A diagnosis of intussusception of the appendix (IA) was made. During the follow-up, IA reduced spontaneously. The present case report is the first description of IA in a patient on hemodialysis therapy. Furthermore, spontaneous reduction of IA is indeed rare.

Appendix↗
PubMed2004

Development of proximal calciphylaxis with penile involvement after parathyroidectomy in a patient on hemodialysis.

Elevated parathyroid hormone (PTH) levels and hyperphosphatemia are thought to be associated with the development of calciphylaxis. We report a patient on hemodialysis who developed proximal calciphylaxis with consistently low PTH levels after parathyroidectomy. A 31-year-old man was admitted to our hospital because of abdominal skin ulcerations. Calciphylaxis spread to the penis, and simultaneous progressive lung calcification was evident on chest X-ray, suggestive of pulmonary calciphylaxis on 99mTc-methylene disphosphonate scintigraphy. The patient died of respiratory failure despite intensive treatment including hyperbaric oxygen therapy. This is the first report of a patient on hemodialysis who developed calciphylaxis involving the penis after parathyroidectomy.

Adult↗
PubMed2004

Development of a camera model and calibration procedure for oblique-viewing endoscopes.

Oblique-viewing endoscopes (oblique scopes) are widely used in medical practice. They are essential for certain procedures such as laparoscopy, arthroscopy and sinus endoscopy. In an oblique scope the viewing directions are changeable by rotating the scope cylinder. Although a camera calibration method is necessary to apply augmented reality technologies to oblique endoscopic procedures, no method for oblique scope calibration has yet been developed. In the present paper, we formulate a camera model and a calibration procedure for oblique scopes. In the calibration procedure, Tsai's calibration is performed at zero rotation of the scope cylinder, then the variation of the external camera parameters corresponding to the rotation of the scope cylinder is modeled and estimated as a function of the rotation angle. Accurate estimation of the rotational axis is included in the procedure. The accuracy of this estimation was demonstrated to have a significant effect on overall calibration accuracy in the experimental evaluation, especially with large rotation angles. The projection error in the image plane was approximately two pixels. The proposed method was shown to be clinically applicable.

Algorithms↗
PubMed2004

Encapsulating peritoneal sclerosis in Japan: a prospective, controlled, multicenter study.

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is recognized as a rare but serious complication of peritoneal dialysis (PD). The aim of this study was to determine the incidence, clinical features, and mortality rate of EPS. METHODS: The authors requested the registration of all PD patients in facilities across Japan where more than 10 patients were treated with PD in this prospective multicenter study. During the 4-year study, the incidence of EPS was observed in the enrolled patients. RESULTS: A total of 1,958 patients who were treated with PD in 57 facilities were followed up from April 1999 through March 2003. EPS occurred in 48 patients, corresponding to an overall incidence of 2.5%. In 33 of the 48 (68.8%) patients, EPS was found after discontinuation of PD. The incidence (and mortality rate) of EPS was 0%, 0.7% (0%), 2.1% (8.3%), 5.9% (28.6%), 5.8% (61.5%), and 17.2% (100%) in patients who had undergone PD for 3, 5, 8, 10, 15, and more than 15 years, respectively. The recovery ratio with total parenteral nutrition, corticosteroids and surgical treatment were 0%, 38.5%, and 58.3%, respectively. Eighteen patients (37.5%) died, 22 (45.8%) recovered, and the status of the other 8 (16.7%) remained unchanged. CONCLUSION: The results of this prospective multicenter study showed that the incidence of EPS was 2.5% within a 4-year observation period and that two thirds of the cases were diagnosed after discontinuation of PD. Because of the current progress in diagnostic technology and therapeutic methodology, it appears that PD can be continued successfully with an acceptable, low risk for EPS for at least 8 years, whereas stricter caution is required for patients receiving PD for longer periods.

Adult↗
PubMed2004

Dialysis dose and nutrition in Japanese peritoneal dialysis patients.

In the present study, we tried to determine the relationship between dialysis dose and nutrition in PD patients. We enrolled 100 Japanese outpatients, including 11 diabetic patients, who were on continuous ambulatory peritoneal dialysis [CAPD (n = 74)] and automated peritoneal dialysis [APD (n = 26)] at 49 local hospitals. In all patients, a peritoneal function test (PET) was performed using the PD NAVI software (JMS, Hiroshima, Japan). The PD NAVI software measured parameters of nutrition and dialysis dose; percentage creatinine generation rate (%CGR); percentage lean body mass normalized to body weight (%LBM); normalized protein nitrogen appearance (nPNA); total fluid removal (TFR), including urine; weekly total Kt/V; and creatinine clearance (CCr). The %CGR correlated linearly with %LBM and nPNA, parameters of the nutrition status of the patients. The %CGR also showed a significant linear correlation with Kt/V, CCr, and TFR. Patients with a %CGR below 100% (the "low group") numbered 37 (32 men, 5 women). The CCr and TFR values in that group were lower than the CCr and TFR values in the other patients (the "high group"). Conclusively, the dialysis dose did not reach the solute clearance values proposed by the National Kidney Foundation Dialysis Outcomes Quality Initiative. That finding may be the result of prescribing and monitoring dialysis therapy based on the PET The %CGR by PD NAVI may become an important index for clinical evaluation of PD dose and optimal dialysis prescription.

Biological Transport↗
PubMed2003

Impaired taste acuity in patients with diabetes mellitus on maintenance hemodialysis.

AIMS: It has been reported that taste acuity for the four primary tastes, sour, sweet, salty and bitter, is impaired in hemodialysis (HD) patients. However, there have been no studies reported on taste acuity of diabetic HD patients. The present study aimed to quantify and compare the taste acuity of diabetic and non-diabetic HD patients, and further to determine if there were correlations between diminished taste acuity and certain blood serum parameters typically askew in hemodialysis patients. METHODS: In a test group of 24 diabetic and 24 non-diabetic HD patients matched for age, body mass index and duration of HD, taste acuity for the four tastes was determined by asking patients to identify them at varying concentrations. RESULTS: Statistical analyses indicate that bitter and total taste acuity were significantly impaired in diabetic HD patients. In diabetic HD patients, correlation was found between sweet, salty or total taste acuity and blood urea nitrogen or normalized protein catabolic rate. CONCLUSIONS: We conclude that taste acuity is partially impaired in diabetic HD patients, and suggest this contributes to reduced appetite, leading to malnutrition and poor prognoses.

Adult↗
PubMed2003

Re-evaluation of adequate dose in Japanese peritoneal dialysis patients.

Our objective in the present study was to evaluate the dialysis dose required to maintain Japanese peritoneal dialysis (PD) patients in good condition. From 32 local hospitals, we selected 100 stable patients without diabetes mellitus who were on continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD), and we performed the peritoneal function test using the newly developed PD NAVI software (JMS, Hiroshima, Japan). Weekly total Kt/V and creatinine clearance (CCr) were calculated and plotted against body weight (BW) to evaluate the PD dose. In CAPD patients (n = 58), we found an inverse linear correlation between total Kt/V and BW (r = -0.576). In the same patients, total Kt remained essentially constant (60 L/week). Those results imply that most patients were being treated with the same PD regimen (2 L, 4 times daily), and that smaller patients were generally receiving a greater PD dose relative to body size than were the larger patients. In APD patients (n = 21), total Kt/V and total CCr normalized to 1.73 m2 did not change with BW. Total Kt and non normalized CCr gradually increased with BW, although the correlation was not significant. Those findings suggest that most APD patients received prescriptions that were more closely based on body size. In conclusion, smaller patients generally receive a greater PD dose than do larger patients, and targeting a single value of Kt/V or CCr may not always be relevant for adequate dialysis.

Body Weight↗
PubMed2002

Early effects of parathyroidectomy on erythropoietin production in secondary hyperparathyroidism.

BACKGROUND: Secondary hyperparathyroidism (2-HPT) has an adverse effect on renal anemia and may cause a hyporesponsiveness to recombinant human erythropoietin (rHuEpo) in patients with chronic renal failure. The early effects of parathyroidectomy (PTx) on renal anemia, erythropoietin production, and nutritional state were examined. METHODS: Twenty-nine patients under hemodialysis therapy received a PTx for 2-HPT. They were prospectively studied regarding hematological parameters, rHuEpo use, plasma erythropoietin levels, and nutritional condition until 12 months after PTx. RESULTS: The hemoglobin level showed a significant increase from 3 months after PTx (10.2% +/- 1.5% to 11.2% +/- 1.3%; P <0.01), associated with a consistent increase of the reticulocyte count. These changes lasted until 12 months after PTx. The plasma erythropoietin level showed a gradual increase of up to about 5 times the level of the preoperative value, until 12 months after PTx (22.6 +/- 10.1 to 106.3 +/- 112.1 mU/mL; P <0.001). The weekly dose of rHuEpo administration decreased after 3 months. The serum levels of albumin and total protein also significantly and gradually improved until 12 months after PTx. CONCLUSIONS: PTx caused a significant early improvement in renal anemia in patients with secondary hyperparathyroidism. This effect may be caused by an enhanced erythropoietin production and may also be partially due to the improved nutritional state after PTx.

Adult↗
PubMed2002

Effect of diabetes on peritoneal function assessed by personal dialysis capacity test in patients undergoing CAPD.

BACKGROUND: We evaluated differences in individual peritoneal membrane transport function and nutritional status in patients with diabetes mellitus (DM) and nondiabetic (non-DM) patients on continuous ambulatory peritoneal dialysis (CAPD). METHODS: We used a newly developed peritoneal function test, personal dialysis capacity, in 88 patients (44 DM and 44 non-DM) on CAPD for 1 to 210 months. Sex, age, past history of peritonitis, and duration of CAPD were matched in DM and non-DM patients. RESULTS: Serum albumin (mean +/- SEM) was lower in DM compared with non-DM patients: 3.0 +/- 0.1 g/dL (30 +/- 1 g/L) versus 3.5 +/- 0.1 g/dL (35 +/- 1 g/L), P < 0.001. Peritoneal area and dialysis protein loss were greater in DM versus non-DM patients. In multiple linear regression analysis, the only independent predictor of serum albumin in patients with DM was dialysis protein loss. In contrast, age, past history of peritonitis, duration of CAPD, caloric intake, protein nitrogen appearance and protein catabolic rate, and residual renal function did not correlate with serum albumin in DM patients. In non-DM patients, age, duration of CAPD, and past history of peritonitis, but not dialysis protein loss, were independent predictors of serum albumin. There was a significant correlation in DM patients, but not in non-DM CAPD patients, between dialysis protein loss and urinary excretion of protein (r = 0.866, P = 0.0005). CONCLUSION: In this multicenter study, peritoneal membrane transport and peritoneal protein permeability were significantly higher in DM than in non-DM patients. Hypoproteinemia in DM patients is attributable to the high permeability of the peritoneal membrane undergoing CAPD.

Age Factors↗