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Biomedical subjects

T Akiba

Publications and source records attributed to T Akiba.

At least 73 records · Page 4Linked to original sources
PubMed1997

Survival in long-term haemodialysis patients: results from the annual survey of the Japanese Society for Dialysis Therapy.

The prognosis for haemodialysis patients is reported to be more favourable in Japan than in Europe or North America. Consequently, evaluation of the death predictors for haemodialysis patients in Japan is of considerable interest outside Japan. The Patient Registration Committee of the Japanese Society for Dialysis Therapy annually surveys the individual patient case mix, laboratory data and important events occurring in the previous years. Thus, using case mix data and laboratory data (including Kt/V and protein catabolic rate) from the 1993 questionnaire survey and the individual patients' life/death statistics from the 1994 questionnaire survey, a logistic regression analysis was conducted on 53867 patients. The analysis indicated that important death risk predictors were: (i) advanced age, (ii) occurrence of diabetes mellitus, (iii) male sex, (iv) Kt/V lower than 1.8, (v) haemodialysis time less than 5 h, (vi) protein catabolic rate less than 0.9 g/kg/day, and (vii) percentage body weight decrease less than 4% and more than 8% during the first haemodialysis session of the week.

Adult↗
PubMed1997

Current status of renal replacement therapy in Japan: results of the annual survey of the Japanese Society for Dialysis Therapy.

Beginning in 1966, the Patient Registration Committee of the Japanese Society for Dialysis Therapy has conducted a survey once a year on renal replacement therapy in Japan. As of 1983, the survey covered the life/death of patients in the survey years, as well as the case mix of individual patients. In 1990 several laboratory variables were added to the survey items. The present report summarizes the data from the 1993 and 1994 surveys. The Committee mailed out questionnaire forms at the end of the survey year to the heads of all dialysis facilities. Survey forms were returned from 99.6% of the dialysis facilities in the 1993 survey, and from 99.8% of the facilities in the 1994 survey. Some 143709 patients were treated by renal replacement therapy in 1994 (7509 were treated by CAPD, and 131016 by extracorporeal haemopurification). The gross mortality rate was 9.5% in the same year. The mean values of the laboratory variables among 88693 patients undergoing thrice weekly haemodialysis were as follows in 1993: Kt/V, 1.31 +/- 0.30; protein catabolic rate, 1.04 +/- 0.30 g/kg/day; haemodialysis time, 4.12 +/- 0.50 h. In 1994, the variables were: predialysis serum creatinine concentration, 11.54 +/- 2.85 mg/dl; predialysis serum albumin concentration, 3.91 +/- 0.55 g/dl; predialysis haematocrit, 28.69 +/- 4.36%.

Aged↗
PubMed1997

Long-term, low-dose, cadmium-induced nephropathy with renal osteopathy in ovariectomized rats.

To establish an animal model of chronic cadmium nephropathy and osteopathy, we intraperitoneally administered 0.228 mg CdCl2 (Cd) or normal saline (NS) to 52 female Sprague-Dawley (S.D.) rats 3 times a week for 16 months following ovariectomy (OV) or sham surgery (Sham), dividing the animals into three experimental groups (OV-Cd, Sham-Cd and OV-NS). Two groups of male S.D. rats were also administered Cd or NS (22 animals; Male-Cd and Male-NS). Cd-administered rats gained significantly less body weight than NS rats after 16 months of experiments with no signs of emaciation. Serum creatinine levels and Cd contents in the kidney had significantly increased in the Cd-administered rats. OV-Cd rats showed significant decreases in PTH levels and increases in calcium contents in the kidney and other organs. Kidneys of Cd-administered rats showed atrophy, dilatation, and interstitial fibrosis of tubules. Sclerosis and collapse of the glomeruli were observed in the Cd groups with no proliferation in mesangial cells or matrix. The Haversian canal system of the Cd-administered rats disappeared and was replaced by a large quantity of degenerated, necrotic, and restorative tissues. Bone histomorphometric parameters showed that osteoid volume and osteoid surface had significantly increased in the Male-Cd group. In contrast, decreases in bone mass and increases in fibrous tissue were found to be more prominent in the OV-Cd group. Our results have demonstrated for the first time that long-term, low-dose CdCl2 administration to ovariectomized S.D. rats is capable of inducing irreversible nephropathy with osteopathy exhibiting pathological and bone histomorphometric characteristics that are very similar to those of Itai-Itai disease.

Animals↗
PubMed1997

Treatment of refractory cases of atopic dermatitis with acidic hot-spring bathing.

The incidence of refractory atopic dermatitis has increased in teenagers and young adults. The purpose of this study was to control the skin symptoms of such patients in daily life. Seventy patients repeatedly took a 10-min 42 degrees C acidic hot-spring bath twice daily. The skin symptoms were improved in 76% of cases. In 30 of 42 responders examined Staphylococcus aureus, detected on the skin surface, disappeared or decreased through balneotherapy. In contrast, S. aureus remained unchanged in 8 of 10 non-responders examined. Thus, the balneotherapy using acidic hot-spring water may be useful for controlling the skin symptoms of acute flares of refractory cases of atopic dermatitis.

Adolescent↗
PubMed1997

Is the bone mass of hemodialysis patients genetically determined?

Polymorphism of the vitamin D receptor gene (VDR) has been linked to bone mineral density in twins, postmenopausal osteoporosis, and premenopausal woman. We examined the possibility that the bone mass in hemodialysis (HD) patients might be determined by VDR. The study consisted of 229 HD patients with a mean age of 53.3 years (range 21 to 83), who were dialyzed three times a week for an average of 8.65 (range 0.2 to 24) years. We determined their VDR using DNA of peripheral white blood cells by restriction enzyme BsmI and the polymerase chain reaction-restriction fragment length polymorphism method. Bone mineral content (BMC) was estimated at 1/3 of the radius using dual energy X-ray bone absorptiometry, and expressed in z-scores standardized by gender and age. Distributions of VDR in this hemodialysis population were BB (9.9%), Bb (13.1%), and bb (77.0%), showing no significant different from those in 105 healthy volunteers (BB, 7.6%; Bb, 13.3%; and bb, 79.0%). Multiple regression analysis revealed that gender, age, duration on HD, and serum osteocalcin are major determinants of BMC (r = 0.762, P < 0.001), while VDR and serum parathyroid hormone are not. In a subgroup with younger (< 65 years) patients dialyzed for less than 8.65 years, the z-score of BMC of patients with BB allele was less than those with Bb and bb allele (N = 77, P = 0.020). We conclude that vitamin D receptor polymorphism is not one of the main determinants of BMC of HD patients, though it might partially effect bone mass in a subgroup of younger HD patients with shorter HD histories. Further studies with longitudinal observation will be needed to confirm these possibilities.

Adult↗
PubMed1997

Incidence and clinical characteristics of hypoparathyroidism in dialysis patients.

The incidence and clinical characteristics of hypoparathyroidism (Hypo) were evaluated in 8188 hemodialysis (HD) and 1207 CAPD patients treated in 65 hospitals or clinics in Japan. Hypo was defined by an intact parathyroid hormone (PTH) level below 160 pg/ml, which corresponded to the low normal limit of intact PTH to maintain a normal osteoblastic surface in 40 bone biopsy specimens of Japanese dialysis patients, and patients were classified into two groups: absolute Hypo (A-Hypo), intact PTH < 60 pg/ml, and relative Hypo (R-Hypo), 60 pg/ml < or = intact PTH < 160 pg/ml. A total of 2537 (31.0%) and 2736 (33.4%) HD patients were classified into A- and R- Hypo, and 401 (31.3%) and 379 (31.4%) CAPD patients occupied A- and R-Hypo, respectively. A high incidence of Hypo was observed in the HD patients with diabetes mellitus (DM) and old age (> or = 70 years old) compared with that of a nationwide epidemiological report for dialysis patients by Japanese Society for Dialysis Therapy. Hypo patients who were treated by CAPD had a background of being younger, having a shorter duration on dialysis, and were less frequently diagnosed with DM than in those Hypo patients on HD. Bone pain and metastatic calcification were observed in approximately 20% and 25% of Hypo patients, respectively. No difference was observed in the background factors and the prevalence of signs and symptoms between the A- and R-Hypo groups, regardless of the mode of treatment (HD or CAPD). These results suggest that a very high incidence and specific backgrounds (DM and aging) of Hypo exist in Japanese dialysis patients.

Adult↗
PubMed1997

Water channel AQP1, 3, and 4 in the human peritoneum and peritoneal dialysate.

To clarify the mechanism of water transport driven by osmotic gradient through "ultrasmall pores" in the peritoneum, we tried to identify water channels in the peritoneum and cells in the peritoneal dialysate. Peritoneum was surgically excised from uremic patients at the insertion or removal of a catheter. Sediment was collected from 2 L of peritoneal dialysate by centrifugation at 1500 rpm. RNA was extracted and amplified by reverse transcription-polymerase chain reaction (RT-PCR). Contamination of reticulocytes was tested by the presence of ankyrin mRNA. Peritoneal tissue expressed aquaporin (AQP) 1, 3, and 4 (AQP1 > 3 > 4). Sediment of dialysate expressed mRNA of AQP1 and AQP3 (AQP1 > AQP3). The sample did not express ankyrin mRNA, indicating that the AQP1 in the sediment did not originate from reticulocytes. These data indicate that aquaporins are present in the peritoneum and might participate in water transport. Further quantitative analysis of aquaporin messages in the dialysate might clarify the pathogenesis of water removal failure.

Ankyrins↗
PubMed1996

Low prevalence of anti-hepatitis C virus antibodies in female hemodialysis patients without blood transfusion: a multicenter analysis.

To investigate whether nosocomial infection with hepatitis C virus (HCV) in chronic hemodialysis patients is related primarily to hemodialysis procedures, a multicenter analysis was carried out on 2,132 chronic hemodialysis patients (male: 1,274, female: 858) from 23 dialysis units using a second-generation anti-HCV antibody assay. The prevalence of anti-HCV antibodies in patients with blood transfusion (29.9%) was significantly higher (P < .0001) than in those without blood transfusion (7.6%). Although the prevalence of anti-HCV antibodies increased with the length of hemodialysis in males without blood transfusion, it did not increase even after long-term hemodialysis (more than 5 years) in females without blood transfusion, who exhibited a rate (1.9%) similar to that of healthy blood donors in Japan. There was a significant correlation between the presence of anti-HCV antibodies and anti-HBs antibody in males without blood transfusion. In anti-HBs antibody-negative male patients without blood transfusion, the prevalence of anti-HCV antibodies was significantly lower compared with anti-HBs antibody-positive male patients without blood transfusion. There was marked difference in the prevalence rate in patients without blood transfusion among dialysis units, and there was no correlation between the prevalence and the mean period of dialysis of each dialysis unit. Although nosocomial infection with HCV appears to be related to the hemodialysis environment, the low prevalence of anti-HCV antibodies in females suggests that dialysis procedures per se may not present the risk of hepatitis C virus infection.

Adolescent↗
PubMed1996

Metabolites of 5-fluorouracil, alpha-fluoro-beta-alanine and fluoroacetic acid, directly injure myelinated fibers in tissue culture.

The neurotoxicity of two 5-fluorouracil (5-FU) derivatives, tegafur (FT) and carmofur (HCFU), which selectively induce leukoencephalopathy involving the cerebral white matter in humans and vacuolation of myelinated fibers in dogs and cats, was examined in vitro. The common metabolites of these drugs, alpha-fluoro-beta-alanine (FBAL) and fluoroacetic acid (FA), were added to the medium of cultured murine cerebellar myelinated fibers. On day 1 of exposure to 7 microM FBAL and FA, which corresponds to their blood concentrations 2 h after oral administration of 10 mg.kg-1 HCFU to dogs that induced central nervous system vacuolation after 30 days, partial splits of the myelinic intraperiod line were observed by electron microscopy. On days 4-7, phase contrast microscopy revealed spindle-shaped swelling and granulation of myelin and electron microscopy demonstrated prominent dissociation of the myelinic intraperiod line with monolocular and multilocular vacuolation. More severe changes, such as myelin loss, were found in cultures exposed to a higher concentration (70 microM) of FBAL and FA, but no remarkable neuronal, astrocytic or oligodendrocytic changes occurred. Quantitative evaluation of myelin injury by electron microscopy revealed significant toxicity of FBAL and FA, at concentrations of 7 and 70 microM, on day 4. However, groups treated with 0.7 microM FBAL and FA, 5-FU (7 microM) and controls exposed to beta-alanine and acetic acid concentrations of 0.7, 7 and 70 microM showed no marked injury. We concluded that these anticancer drug metabolites injure myelin fibers directly, resulting in vacuolation due to myelin splitting and destruction.

Animals↗
PubMed1996

Three-dimensional structure of bovine cytochrome bc1 complex by electron cryomicroscopy and helical image reconstruction.

Cytochrome bc1 complex from bovine heart has been reconstituted into tubular crystals. The three-dimensional structure of the complex in lipid bilayer has been obtained at an effective resolution of 16 angstrom by electron cryomicroscopy and helical image reconstruction. The complex is in a dimeric form, in which the monomers are associated closely in extramembrane domains on both sides of the membrane. The large inner domain is distinctively hollow and the small outer domain consists of a flat mass and two bulbous extrusions. These domains are connected by two narrow transmembrane columns. Locations of the subunits and the redox centres in the model are proposed.

Animals↗
PubMed1996

Effect of 22-oxacalcitriol on hyperparathyroidism of dialysis patients: results of a preliminary study.

Intermittent high dose administration of calcitriol or alfacalcidol is effective in suppressing secondary hyperparathyroidism in chronic dialysis patients, however calcaemic action of these vitamin D derivatives is a major obstacle. 22-Oxacalcitriol (OCT) has been reported to have less calcaemic action than calcitriol, while preserving a comparable suppressive effect on parathyroid hormone (PTH) secretion. This preliminary study was conducted to examine the effects of OCT on secondary hyperparathyroidism in chronic dialysis patients. OCT was administrated intravenously immediately after every haemodialysis session three times a week for 12 weeks to three haemodialysis patients with secondary hyperparathyroidism. An initial dose of OCT of 5.5 micrograms/haemodialysis session was increased stepwise by 5.5 micrograms/haemodialysis up to 22 micrograms/haemodialysis according to the suppression of PTH and calcaemic action. OCT was discontinued for at least a week when serum calcium adjusted to albumin concentration measured just before haemodialysis exceeded 11.5 mg/dl. Marked reduction in plasma PTH, alkaline phosphatase and tartrate-resistant acid phosphatase was observed in all three patients. Although the dose of OCT was increased to 22 micrograms/haemodialysis in one patient, the final dose of OCT remained 5.5 micrograms/haemodialysis in the other two patients because of hypercalcaemia. It is concluded that OCT is highly effective in suppressing PTH in dialysis patients with secondary hyperparathyroidism. Hypercalcaemia may be a major factor which limits the use of OCT, though it may occur with higher doses of OCT than those of calcitriol usually given to suppress PTH hypersecretion.

Calcitriol↗
PubMed1996

Left and right ventricular volume characteristics in tetralogy of Fallot and their relationship to arterial oxygen saturation and age.

Left (LV) and right ventricular (RV) volume characteristics in 43 patients with tetralogy of Fallot (TOF) undergoing no prior surgical intervention, aged 3-50 months, were evaluated. The control group consisted of 45 patients with Kawasaki disease without cardiac lesions, aged 12-82 months. The TOF patients were divided into four groups: those having arterial oxygen saturation < 80% with an age at the time of study < 18 months (group 1a) or with that > or = 18 months (group 1b), and those with arterial oxygen saturation > or = 80% with an age < 18 months (group 2a) or with that > or = 18 months (group 2b). The results were compared with those in control subjects. In group 1a, each of LV end-diastolic volume (EDV), LV ejection fraction (EF), RVEDV and RVEF was reduced. In group 1b, LVEDV, LVEF and RVEF were decreased. In groups 2a and 2b, RVEF alone was depressed. From these results, the severity of hypoxemia was an important risk factor for ventricular dysfunctions. No influence of age on the volume characteristics was found. The investigations suggested that patients with TOF having an arterial oxygen saturation < 80% are probably candidates for early surgical intervention.

Age Factors↗
PubMed1996

One-compartment urea kinetic modeling is not acceptable for quantifying the adequacy of hemodialysis: comparison of a one-compartment model with a two-compartment model.

We can quantify the adequacy of hemodialysis (HD) as the dialysis dose using urea kinetic modeling (UKM). Though the one-compartment model (1CM) has frequently been applied, there are some studies which have successfully applied the two-compartment model (2CM) including urea rebound. To clarify whether 1CM or 2CM is more acceptable, we analyzed 100 patients using UKM, applying each model. The dialysis dose was defined as the logarithm of pre-/post-HD urea volume in the body. In about half the patients analyzed, 1CM estimation of the dialysis dose exceeded 2CM estimation by more than 10%, and the 1CM was not considered to be acceptable.

Adult↗
PubMed1996

Characteristics of anti-HCV antibody-positive patients with hepatocellular carcinoma on chronic hemodialysis: recommendation of periodic ultrasonography for early detection.

We analyzed 10 patients (male:female 9:1, mean age 64.2 years) who developed hepatocellular carcinoma during the observation period of 2 years among 2,164 chronic hemodialysis patients in 23 dialysis centers. Among them, 409 patients were positive for serum anti-HCV antibodies (19%). They were all positive for serum anti-HCV antibodies but negative for HBs antigen. None of the anti-HCV antibody-negative patients developed hepatocellular carcinoma during this period. Although liver function tests of the patients were almost normal, pathological examination of the liver revealed chronic active hepatitis or cirrhosis. Periodic ultrasonographic examination is necessary for early detection of hepatocellular carcinoma in chronic hemodialysis patients with positive anti-HCV antibodies even if liver function tests are within normal ranges.

Aged↗
PubMed1996

Levels of serum 1,25(OH)2D in patients with pre-dialysis chronic renal failure.

One hundred and ninety-five outpatients in pre-dialysis period served as subjects. The mean age of subjects was 58.0 +/- 11.2 (range: 29-82) years. The subjects were divided into 8 groups according to their serum creatinine (Cr) levels (Cr < or = 1.0, 1.0 < Cr < or = 2.0, 2.0 < Cr < or = 3.0, 3.0 < Cr < or = 4.0, 4.0 < Cr < or = 5.0, 5.0 < Cr < or = 6.0, 6.0 < Cr < or = 8.0, and Cr > 8.0 mg/100 ml). The level of 1,25-dihydroxyvitamin D (1,25(OH)2D) decreased in accordance with the progression of chronic renal failure (CRF). Even in subjects with 1.0 < Cr < or = 2.0 mg/100 ml, the levels of 1,25(OH)2D were significantly lower than those in subjects with Cr < or = 1.0 mg/100 ml. The levels of calcium adjusted by serum albumin levels (adjusted Ca) were relatively maintained within the normal range until Cr > 8.0 mg/100 ml. The levels of inorganic phosphate (IP) were significantly lower in subjects with 1.0 < Cr < or = 2.0 mg/100 ml, but significantly higher in subjects with Cr > 4.0 mg/100 ml than those in subjects with Cr < or = 1.0 mg/100 ml. The levels of immunoreactive high-sensitive parathyroid hormone (HS-PTH) were greatly increased and the levels of intact PTH were significantly increased even in subjects with 1.0 < Cr < or = 2.0 mg/100 ml, in association with a decrease in levels of 1,25(OH)2D suggesting that a decline in 1,25(OH)2D production due to a decrease in renal mass contributes to the acceleration of secondary hyperparathyroidism. When the levels of adjusted Ca, intact PTH and 1,25(OH)2D of subjects with hypophosphatemia (IP < 2.8 mg/100 ml), normophosphatemia and hyperphosphatemia (IP > 4.4 mg/100 ml) were compared, there were not any significant differences in the levels of adjusted Ca among these subjects in each group. But, the levels of 1,25(OH)2D in subjects with hypophosphatemia were significantly higher than those with normophosphatemia in groups with Cr < or = 2.0 mg/100 ml, and those with hyperphosphatemia were significantly lower than those with normophosphatemia in groups with 3.0 < Cr < or = 4.0, 5.0 < Cr < or = 6.0 and Cr > 8.0 mg/100 ml. These results suggest that increased secretion of PTH might compensate the decreased production of 1,25(OH)2D3 by lowering phosphate in the early phase of CRF, and phosphate retention inhibits the activity of 1 alpha-hydroxylase and contributes to the decrease in 1,25(OH)2D3 in the advanced stage of CRF. Monitoring of 1,25(OH)2D is considered to be vitally important for diagnosing the 1,25(OH)2D3 deficiency in CRF.

Adult↗