Hemodialysis restored iron distribution that was sequestered in the spleen by bilateral nephrectomy.

Acute kidney injury (AKI) is associated with dysregulated iron metabolism, which may play a significant role in cellular injury. The effect of hemodialysis (HD) on iron metabolism in AKI therapy has not been well defined. The effects of HD on iron parameters were tested in control rats and bilateral nephrectomy (BNx) rats. The BNx rats were divided into the following three groups: 1) the sham-operated group (BNx-Sham), 2) the BNx group, and 3) the HD group (BNx-HD), which received HD therapy 40-45 h after BNx. Sections of the liver or spleen were stained with Berlin blue to examine the accumulation of iron. The mRNA levels of hepcidin and ferroportin 1 in the spleen and liver were also quantified using RT-PCR. In the BNx group, the plasma iron and hematocrit levels were decreased, and hepcidin levels were increased. The iron staining in the spleen in the BNx group was significantly more intense than that in the BNx-Sham group; however, after an HD session, splenic iron staining diminished to the level of the sham group along with an increase in plasma iron and a decrease in hepcidin. BNx moved iron from hemoglobin and the plasma to the spleen, which is associated with an increase in plasma hepcidin. A single HD session accelerated the release of iron from the spleen, and the increased plasma iron was linked to the removal of hepcidin. Our data suggested that hepcidin might dynamically modulate the iron metabolism in BNx as well as in HD.

New peritoneal dialysis model in rats with bilateral nephrectomy.

Many peritoneal dialysis (PD) patients with chronic renal failure (CRF) suffer from metabolic and nutritional abnormalities. However, these abnormalities have been not sufficiently investigated. At present, the resolution of these issues in this field has been hindered by the lack of suitable PD models. We attempt to develop a rat model of PD under no constraints and under non-anesthetization to evaluate amino acid solution as suitable nutritional therapy for renal failure. In our model, bilateral nephrectomy rats were dialyzed 6 h per day for three days. The dialysate was infused and removed continually via a metering pump. Under fasting, rats were infused with 5% glucose or amino acid solution for renal failure, and they remained alive. This model can be used to examine bilateral nephrectomy in rats for three or more days. We were also able to determine protein and calorie malnutrition, negative nitrogen balance, abnormalities in the plasma amino acid pattern, and calcium and phosphorus metabolism. Thus, this model has the characteristics of renal failure in humans and may be used to easily examine the metabolic changes due to loss of kidney function.

[Basic study on the mechanism of postanesthetic recovery acceleration caused by infusion of bicarbonated Ringer's solution].

BACKGROUND: Effect of bicarbonated Ringer's solution (BRS) on the liver function of rats with metabolic acidosis was compared with that of lactated Ringer's solution (LRS) and Ringer's solutions (RS). Furthermore, the effect of acidosis on the plasma protein binding ratio of propofol was examined. METHODS: Partial hepatectomized rats were divided into three groups, and BRS, LRS or RS was intravenously administered at 20 ml x kg(-1) x hr(-1) with propofol (45 mg x kg(-1) hr(-1)) for 90 min. Immediately after the administration, indocyanine-green (ICG) was infused. Blood sampling was done at 30, 60, 90 and 120 min after the ICG infusion, and the ICG concentration in plasma was measured. Propofol was added to plasma of rats with ketoacidosis or normal rats (final conc. 5 microg x ml(-1)), and incubated for 30 min at 37 degrees C. After incubation, plasma propofol concentrations were measured. RESULTS: The reduction of ICG in plasma of BRS group was the fastest among the three groups. Plasma protein binding ratio of propofol in plasma samples of rats with ketoacidosis tended to be lower than those of normal rats samples. CONCLUSIONS: These results suggest that metabolic acidosis induced the delay of awakening from anesthesia, suggesting that BRS accelerates recovery from anesthesia through amelioration of acidosis.

[Influence of a long-term load of dietary cholesterol on the rat kidney].

The involvement of hyperlipidemia in aggravation of nephrosis has remained controversial. In this study, to examine the influence of cholesterol on the kidney, normal SD rats were loaded with a normal diet(4.4% fat, 0.09% cholesterol) plus 0.25% cholesterol for 10 months, and the urinary excretion of protein, blood cholesterol level and histological renal changes were compared with those in the control group given the normal diet alone. The urinary protein excretion was increased after 4 months of cholesterol loading and was about 6 times the control value at the end of the study(10 months). At 10 months, the blood levels of total, HDL- and LDL + VLDL-cholesterols were also increased, and the arteriosclerosis index(HDL/LDL + VLDL ratio) was about 1.3 times the control value. Histologically, segmental lesions of glomeruli containing sclerosis/PAS positive material were stronger than in the control animals. Thus, this study revealed increased blood cholesterol and urinary protein excretion and aggravated histological changes of the kidney in rats given a long-term cholesterol load, suggesting that cholesterol may be a risk factor affecting the kidney.

Determination of D-amino acid oxidase activity in tumour cells.

BACKGROUND: We evaluated the assay for determining D-amino acid oxidase (DAAO) activity in tumour cells, rat liver and rat kidney for studying the effects of D-amino acid-containing solution on cancer patients. METHODS AND RESULTS: In this method the amount of ammonia produced by the DAAO activity after removal of endogenous ammonia using a Sephadex G25 column was determined. The highest activity was observed in rat kidney, which was almost eight times that found in rat liver. As compared with host tissues, the DAAO activity in tumour cells was considerably less. CONCLUSIONS: This DAAO assay may be useful for analysis of various tissue samples as well as tumour cells.