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Biomedical subjects

T Akiba

Publications and source records attributed to T Akiba.

At least 37 records · Page 2Linked to original sources
PubMed2001

Soluble osteopontin and vascular calcification in hemodialysis patients.

BACKGROUND: Vascular calcification often occurs in patients with uremia. As osteopontin (OPN) is not only involved in the physiological but also the pathological calcification of tissues, OPN may be associated with the pathogenesis of aortic calcification in hemodialysis (HD) patients. METHODS: We examined the expression of OPN in atherosclerotic aortas of HD patients. In addition, we performed a prospective longitudinal study by using CT scans to detect aortic calcifications and by measuring the plasma OPN concentration by ELISA in HD patients (20 men, 16 women; mean age 55.2 +/- 21.3 years) and in healthy volunteers (18 men, 17 women; mean age 54.0 +/- 13.2 years). RESULTS: By immunohistochemical staining, OPN was abundantly localized in atherosclerotic plaques of HD patients. The macrophages surrounding the atheromatous plaques were identified as the OPN-expressing cells. We furthermore found that the concentration of soluble plasma OPN was significantly higher in HD patients as compared with the concentrations in age-matched healthy volunteers (837.3 +/- 443.2 vs. 315.1 +/- 117.4 ng/ml, p < 0.01). The OPN concentration was positively correlated with the aortic calcification index in HD patients (r = 0.749, p < 0.01). CONCLUSION: These data suggest that OPN, secreted by macrophages, plays a role in the calcification of atheromatous plaques in HD patients.

Adult↗
PubMed2001

Analysis of beta(2)-microglobulin kinetics in hemodialysis by a modified variable-volume one-compartment model.

It has been reported that deposition of beta(2)-microglobulin (BMG) is associated with the occurrence of dialysis-related amyloidosis (DRA) in long-term hemodialysis (HD) patients. Though reduction of the BMG burden is essential in preventing DRA, simple BMG kinetic models applicable to clinical practice have not been established. We have reported a modified variable-volume one-compartment model (1CM) for analyzing urea nitrogen (UN) kinetics, in which no specific parameters other than a modification factor are necessary. If there is a constant relation between the BMG concentration of the dialyzer arterial line and the mean BMG concentration in the body during HD, the modified 1CM may also be applied to BMG. As such, in order to verify its validity, we analyzed UN and BMG kinetics by the modified 1CM in 28 HD patients in whom polysulfone dialyzers were used, and compared the calculated and measured solute rebound. In 3 of the patients, the spent dialysate was collected in a tank, and the BMG removal mass, calculated by the modified 1CM, was compared with that recovered in the tank. The BMG rebound ratio (%), calculated by the modified 1CM, was not different from the measured one (36.3 +/- 9.9 vs. 36.5 +/- 11.5, p = 0.954), as in the case of UN (15.8 +/- 4.5 vs. 16.3 +/- 4.6, p = 0.541). The solute dilution in the blood circuit by solute disequilibrium and blood recirculations for BMG was estimated to be 74% stronger than that for UN. The normalized solute generation rate (mg/min/l) and the time-averaged solute concentration over a 1-week period (mg/l) were 0.142 +/- 0.023 and 448 +/- 68 for UN and 0.00578 +/- 0.00125 and 22.4 +/- 4.6 for BMG, respectively. The differences between these two solutes resulted in a Dilution index for BMG that was 23% lower than that for UN (2.62 +/- 0.44 vs. 3.21 +/- 0.39, p < 0.0001). The modified 1CM overestimated the BMG removal mass (mg) by about 20% compared with that recovered in the tank (195 +/- 22 vs. 162 +/- 17, p < 0.0001). One of the causes of this discrepancy was speculated to be adsorption of BMG by polysulfone dialyzers. It was concluded that, despite several problems in quantitative analysis, the modified 1CM would be a useful model for estimating the dialysis efficiency for BMG removal in clinical practice.

Adsorption↗
PubMed2001

Glomerulonephritis after methicillin-resistant Staphylococcus aureus infection resulting in end-stage renal failure.

A 58-year-old man developed proteinuria and renal dysfunction following pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin was administered, and prednisolone pulse therapy and plasmapheresis were performed. Subsequently, serum creatinine was decreased. Eight months later, creatinine and CRP were again elevated, and MRSA was detected. Vancomycin was again administered and plasmapheresis was performed. However, renal function was not improved and continuous hemodialysis was initiated. This case indicates that complete eradication of MRSA is necessary to treat MRSA-associated glomerulonephritis, and if this is not attained, a permanent loss of renal function occurs.

Anti-Bacterial Agents↗
PubMed2001

IgA nephropathy with complement deficiency.

We treated a female patient suffering from immunoglobulin A (IgA) nephropathy and congenital deficiency of the ninth component of the complement system (C9). She was admitted with hematuria and proteinuria, and the C9 deficiency was diagnosed based on the low hemolytic activity of 50 % of the hemolytic unit of the complements (CH50) and the normal C3 level in the plasma. Renal biopsy revealed mild mesangial proliferation, and immunofluorescence examination revealed mild mesangial deposits of IgA and C3 with the same distribution. We discuss the pathogenesis of IgA nephropathy and the role of the complements in its progression.

Adult↗
PubMed2001

Analysis of Japanese encephalitis epidemic in Western Nepal in 1997.

We conducted an epidemiological study of a Japanese encephalitis (JE) outbreak in the southwestern part of Nepal in 1997. A high density of JE infections was found and it was estimated that 27.9% the total population were infected with JE virus in the study area. The fatality rate was 13.2% and there was no difference in the fatality rate between males and females over 5 years old. However, the case fatality rate was 2.1 times higher in females than in males (14.6% vs. 6.9%) among children under 5 years of age. Fifty-three blood samples were collected from suspected JE cases during the epidemic period in 1998. Findings for JE specific IgM revealed that clinical diagnoses of JE were serologically confirmed in an average 78% (70-93%) of patients in three collaborating hospitals. These studies demonstrated that JE was highly prevalent in the area and clinical diagnoses were reliable. Effective preventive measures should be taken against this vaccine-preventable disease.

Adolescent↗
PubMed2001

[Renal dysfunction and hyperphosphatemia--role of hyperphosphatemia on vascular calcification].

Coronary-artery calcification was present in 14 of 16 hemodialysis patients who were 20 to 30 years old by electron-beam computed tomography. Bone matrix protein, such as osteopontin produced by infiltrating macrophages into the atherosclerotic arterial lesions, is thought to be associated with vascular calcification. Therefore, it is required to recognize the interaction between abnormal bone metabolism and vascular calcification. Control of serum phosphorus levels is likely to be most important for the prevention and treatment of vascular calcification in patients with end-stage renal diseases.

English Abstract↗
PubMed2000

Analysis of urea nitrogen and creatinine kinetics in hemodialysis: comparison of a variable-volume two-compartment model with a regional blood flow model and investigation of an appropriate solute kinetics model for clinical application.

To investigate an appropriate solute kinetics model for clinical application, we analyzed urea nitrogen (UN) and creatinine (Cr) kinetics by a variable-volume two-compartmental model (2CM) and a regional blood flow model (RBF) in 44 hemodialysis patients with varying proportions of first compartmental volume and regional volume (p(1)). Solute kinetics could not be solved in some of the patients with higher p(1) values, and there were more solution failures by the RBF than by the 2CM. The solute generation rate (g) and solute distribution volume in the dry state (V(D)) increased with increases in p(1) in both models, but there were some differences between the two models. When g was normalized by V(D), it became relatively constant, irrespective of the p(1) value or model used (0.133 +/- 0.029 mg/min/l by the 2CM and 0.132 +/- 0.029 mg/min/l by the RBF for UN; 0.0200 +/- 0.0049 mg/min/l by the 2CM and 0.0198 +/- 0.0048 mg/min/l by the RBF for Cr). The intercompartmental mass transfer coefficient (K(c); liters/min) calculated by the 2CM decreased as p(1) increased (K(c) = -1.77.p(1) + 1.16, p < 0.0001, R = 0.999 for UN; K(c) = -0.847.p(1) + 0.556, p < 0.0001, R = 1.000 for Cr). The systemic blood flow (Q(sys); liters/min) calculated by the RBF also decreased as p(1) increased (Q(sys) = -11.1.p(1) + 6.21, p < 0.0005, R = 1.000 for UN; Q(sys) = -5.22.p(1) + 2.90, p < 0.001, R = 0.999 for Cr). Since the RBF more frequently failed to solve the solute kinetics and since there was a difference in its Q(sys) values for UN and Cr, the 2CM was considered to be a superior model. When p(1) was extremely low, the 2CM could be transformed into a modified variable-volume one-compartment model (1CM) which presented a similar g/V(D) (0.133 +/- 0.029 for UN; 0.0200 +/- 0.0048 for Cr). This modified 1CM was considered to satisfy appropriate conditions for clinical application, since it is simpler than the 2CM and provides useful information on the dialysis dose.

Aged↗
PubMed2000

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 12). Effects of cyclophosphamide on spermatogenesis.

To determine what is an appropriate administration period for evaluation of the testicular toxicity of cyclophosphamide, the compound was administered orally to male Crj:(CD)SD rats at doses of 5, 10, 20 and 40 mg/kg/day for 2 weeks and at doses of 2.5, 5 and 10 mg/kg/day for 4 weeks. All animals in the 2-week treatment group given 40 mg/kg/day died during the treatment period. After repeated dosing, weights of testes and epididymides did not change significantly in either 2-week or 4-week treatment groups. On conventional histopathological examination, changes in spermatogonia were too subtle to allow simple quantitative evaluation. Therefore the quantitative analysis described by Matsui et al. (1995) was employed. After 4-weeks treatment all types of germ cells decreased significantly in all stages of seminiferous tubules examined in the 10 mg/kg/day group. Spermatogonia type A in all stage seminiferous tubules examined and spermatogonia type B in stage V seminiferous tubules decreased significantly in the 5 mg/kg/day group. With 2-weeks treatment, spermatogonia type A in all stage seminiferous tubules examined were similarly decreased significantly in 10 mg/kg/day or more groups. Spermatogonia type B and pachytene spermatocytes in stage V, preleptotene spermatocytes in stage VII and zygotene spermatocytes in stage XII were decreased in 20 mg/kg/day group. Sertoli cells and the Leydig cells and epididymides were not affected in any treatment group. In conclusion, testicular toxicity induced by cyclophosphamide could be detectable after 2-weeks as well as after 4-weeks treatment if precise histopathological examination including quantitative analysis of spermatocytes are conducted.

Administration, Oral↗
PubMed2000

[The clinical application of a new method for sealing the cut surface of lung using the photopolymerized synthetic bioabsorbable hydrogel (Advaseal)].

We report a case of 67-years-old male, who suffered right upper lobectomy for primary lung cancer. The upper-middle interlobar surface of right lung was incomplete interlobe. Many air leakages were noted in the cut surface of upper-middle interlobe during the sealing test. We sealed this cut surface of upper-middle interlobe by using the photopolymerized synthetic bioabsorbable hydrogel (Advaseal). Air leakage was not noted during the sealing test, and no leakage was not noted after operation. We have observed no biological toxicity (such as cytotoxicity, hemolytic toxicity, systemic toxicity or mutagenic toxicity) by using Advaseal. The new photopolymerized synthetic bioabsorbable hydrogel (Advaseal) is a effective sealant against pulmonary air leaks in the cut surface of the lung.

Aged↗
PubMed2000

Hyperthermia combined with re-irradiation for neck node metastasis from head and neck cancer.

UNLABELLED: The effects of hyperthermia combined with re-irradiation were compared with those of reirradiation alone using retrospectively matched-pair analysis. Between 1984 and 1997, 12 patients were treated with hyperthermia combined with re-irradiation for neck node metastasis from squamous cell carcinoma of the head and neck. During the same period, 12 patients treated with re-irradiation alone were selected retrospectively using the same anatomical diagnosis, nodal site, and nodal size. Recurrent nodes were heated by a 2450MHz microwave or 13MHz radio frequency 4 times on average for 30 to 50 min immediately before radiotherapy. The maximum temperatures were >41degrees C in 83% and >42 degrees C in 58% of patients. RESULTS: The median survival and median recurrence periods were 12 months and 6 months, respectively in both groups. The response rate was 83% in both groups. Nodal size and radiation dose, but not heating temperature, were prognostic factors. Five patients in the hyperthermia group experienced skin ulcers or burns as acute complications. Late complications were observed in one patient in the hyperthermia group and 3 patients in the re-irradiation-alone group. CONCLUSION: Heating induced acute complications and had no significant effect on the tumors. Further advances in hyperthermic technique are required.

Combined Modality Therapy↗
PubMed1999

An extremely large solitary primary paraganglioma of the lung: report of a case.

We present herein the case of a 38-year-old woman found to have an extremely large solitary primary paraganglioma of the lung. The patient presented with chest pain on exertion and a mass was discovered in the left lower lobe of the lung by chest X-rays and computed tomography (CT). As no other neoplasms were detected elsewhere, a left lower lobectomy was performed. The patient has remained well without any evidence of recurrence for 5 years since her operation. The tumor, measuring 13 x 12 x 7 cm, was composed of ovoid cells (Zellballen), which were positive for Fontana-Masson and Grimelius stains, and sustentacular cells. Immunohistochemically, the ovoid cells were positive for neuron-specific enolase, S-100, CAM5.2, Leu7, and chromogranin A, and negative for carcinoembryonic antigen and epithelial membrane antigen. The sustentacular cells were positive for S-100 protein and CAM5.2, and negative for glial fibrillary acid protein. Therefore, the tumor was diagnosed as a paraganglioma. The tumor from our patient is the largest of the 17 solitary primary pulmonary paragangliomas reported thus far in the English-language literature.

Adult↗
PubMed1999

Report of the annual statistical survey of the Japanese Society for Dialysis Therapy in 1996.

BACKGROUND: Nearly 170,000 patients were treated by maintenance renal replacement therapy (RRT) in Japan in 1996. The current status of Japanese patients on RRT might, in some way, be suggestive for patients on RRT in other countries. METHODS: The Japanese Society for Dialysis Therapy conducts a questionnaire survey of virtually every dialysis facility in Japan at the end of each year. Here we present the results of our survey of patients undergoing RRT as of the end of 1996, as well as five-year trends (1992-1996) in some of the data. RESULTS: The response rate was 99.8%. At the end of 1996, there were 167,192 patients on maintenance RRT in Japan (1,328 persons per million population). The numbers of patients on maintenance RRT continued to increase during the five-year period. The gross mortality rate for that period ranged from 9.4% to 9.7%. Cuprammonium rayon was the most commonly used material (24.0%) for dialyzer membranes, followed by cellulose triacetate (18.7%). Approximately 5.0% of hemodialysis (HD) patients had a prior history of surgical release of carpal tunnel. The longer the years on HD therapy, the greater the proportion of patients with a history of such an operation. The predialysis plasma beta 2-microglobulin concentration was highest in patients aged 30 to 45 years and declined slightly after the age of 45. There was no significant difference in the HbA1c level between continuous ambulatory peritoneal dialysis and HD patients, both in whom diabetes was the disease causing renal failure. Moreover, among HD patients with diabetes, there was a clear tendency for the HbA1c level to be higher when the normalized protein catabolic rate was higher. CONCLUSION: This report summarizes the latest results of the survey on Japanese patients on RRT.

Adult↗
PubMed1999

Effects of niceritrol on faecal and urinary phosphate excretion in normal rats.

BACKGROUND: Phosphate binders such as aluminium hydroxide and calcium carbonate have several side-effects so that they are not ideal for clinical use. Recently we reported that administration of niceritrol at 750 mg/day to patients with HDL hypocholesterolaemia undergoing dialysis decreased the serum phosphate concentration. To clarify the mechanism of reduction of the serum phosphate concentration by niceritrol in patients undergoing dialysis, the effects of niceritrol on faecal and urinary phosphate excretion were examined in normal rats. METHODS: Niceritrol suspension in 5% gum arabic was administered for 4 days in normal rats. Faeces and urine were collected in metabolic cage and analysed for phosphate content. RESULTS AND CONCLUSIONS: Faecal phosphate excretion significantly increased in the groups with administration of 100 and 500 mg/kg niceritrol, but not in the group with 20 mg/kg. On the other hand, urinary phosphate excretion was not significantly changed in the groups on 20-500 mg/kg. Retention of phosphate was significantly suppressed in the groups on 100 and 500 mg/kg. A increased faecal phosphate excretion by niceritrol is presumably the mechanism by which serum phosphate concentration is reduced in dialysis patients.

Animals↗