Dietary supplementation with canthaxanthin and 25-hydroxycholecalciferol on the incubation performance and fertility of European quail breeders.

This study assessed the effects of combined supplementation with canthaxanthin (Cx) and 25-hydroxycholecalciferol (25-OH-D3) on incubation performance, fertility, and chick quality in European quail breeders. A total of 240 birds were distributed in a completely randomized design with 5 diets and 8 replicates. The animals were fed a basal diet containing 50 µg of vitamin D3 or the basal diet supplemented with 3 ppm Cx and 34.5 µg 25-OH-D3, 6 ppm Cx, and 69 µg 25-OH-D3, 9 ppm Cx and 103.5 µg 25-OH-D3, or 12 ppm Cx and 138 µg 25-OH-D3. Incubation performance was analyzed in 2 periods (32 and 38 wk). Breeders aged 32 wk produced eggs with higher hatchability (P = 0.024), hatchability of fertile eggs (P = 0.026) and lower initial plus mid embryonic mortality (P = 0.021), whereas 38-week-old breeders generated chicks with a higher length at hatching (P < 0.001) and lower final plus pipped embryonic mortality (P = 0.021). In both age groups, Cx + 25-OH-D3 levels had a quadratic effect on egg fertility (P < 0.001), hatchability of total (P < 0.001), and fertile eggs (P < 0.001). The fertility and the number of sperm cells in the perivitelline membrane was analyzed in two periods (26 and 40 wk). A quadratic effect of diet and days after mating on both parameters (P < 0.05) was observed. Eggs from supplementing breeders showed a high fertility (P < 0.001) and sperm cell counts (P < 0.001) for up to 7 and 3 d after mating, respectively, then the control group. Moreover, the supplementation of quail breeder diets with 6 ppm Cx + 69 µg 25-OH-D3 enhances sperm cell longevity in sperm storage tubules, hatchability of total and fertile eggs, fertility, and chick quality, especially in older quail's breeders and reduces embryonic mortality.

Dietary supplementation with canthaxanthin and 25-hydroxycholecalciferol has beneficial effects on bone and oxidative metabolism in European quail breeders.

This study aimed to investigate the effect of supplementation with canthaxanthin (Cx) and 25-hydroxycholecalciferol (25-OH-D3) on the production performance, egg quality, bone mineral content, blood biochemical parameters, and antioxidant status of European quail breeders. Two hundred and forty quail breeders were distributed in a completely randomized design with 5 diets and 8 replicates of 4 females and 2 males were used. All quail breeders received one of 5 diets: basal diet (containing 2,000 IU vitamin D3) or the same diet supplemented with 3 ppm Cx and 34.5 µg 25-OH-D3, 6 ppm Cx and 69 µg 25-OH-D3, 9 ppm Cx and 103.5 µg 25-OH-D3, or 12 ppm Cx and 138 µg 25-OH-D3. Production performance and internal and external egg quality parameters were not influenced by diet. Eggshell dry weight decreased linearly with increasing supplementation levels, and eggshell ash and calcium content increased quadratically. Plasma phosphorus, calcium, and ionic calcium levels in females and plasma ionic calcium levels in males showed a positive quadratic response to dietary supplementation. Femoral and tibiotarsal dry weight and calcium content were influenced by diet. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity in the liver of males and females and in the serum of females showed a positive quadratic relationship with Cx and 25-OH-D3 levels, whereas the malonaldehyde concentration showed a negative quadratic relationship. DPPH scavenging activity in the serum of male quail increased linearly with supplementation. There was a positive quadratic effect on superoxide dismutase gene expression and a positive linear effect on glutathione peroxidase 7 gene expression, suggesting that dietary enrichment with Cx and 25-OH-D3 might help protect spermatozoa against oxidative damage. The dietary supplement was pro-oxidative at high concentrations (above 9 ppm Cx). The results indicate that diets with adequate levels of Cx and 25-OH-D3 have a beneficial effect on calcium and phosphorus metabolism as well as on the antioxidant defense system. We recommend supplementing European quail breeders in the laying period with 6 ppm Cx and 69 µg 25-OH-D3.

Development and growth of digestive system organs of European and Japanese quail at 14 days post-hatch.

The objective of this study was to evaluate the development and growth of the digestive system organs, from the 11th day of incubation until the 14 d post-hatch in European and Japanese quail. On days 11, 13 and 15 of incubation at hatch and at 4, 7, 10 and 14 d post-hatch, embryos or chicks of European and Japanese quail were analyzed. After 15 d of incubation, samples from stomach and small intestine were analyzed by microscopy. European quail had significantly heavier body weight at 15 d of incubation and after 4 d post-hatch. The digestive system weight progressively increased with age and was similar between European and Japanese quail at 11, 13, and 15 d of incubation and 10 d post-hatch, while relative weight of digestive system was similar between quail type with great values at 4 d post-hatch. For relative weight of the small intestine + pancreas, the weight of the proventriculus and of the gastric ventricle increased significant by among ages analyzed in both types of quail. At hatch, proventriculus had functional secretory cells and mucosa of gastric ventricle had a thin coilin membrane. In small intestine segments, at 15 d of incubation the height of the villi was similar among duodenum, jejunum, and ileum (80 µm). Villi had elongated shape towards the intestinal lumen, covered by enterocytes and dispersed goblet cells with PAS+ and AB+ contend in all segments. The number of goblet cell/villi increased in segments until 7 to 10 d post-hatch. Duodenum increases the villi up to 14 d, while the jejunum and ileum up to 10 and 4 d, respectively. Based on our data in digestive system growth, a shorter period of post-hatch fast and specific diets to quail during first days of growth is recommended to both quail types. It is concluded that the development and growth of different organs of the digestive system up to 14 d of age was similar between European and Japanese quail.

A 13-week subchronic oral toxicity study of L-serine in rats.

A subchronic oral toxicity study was conducted to evaluate the safety of L-serine in Sprague-Dawley rats. The test article was administered once daily by gavage in male and female rats at dose levels of 0, 500, 1500, and 3000 mg/kg body weight/day for 13 weeks. Daily clinical signs, body weight, and food consumption were not affected by ingestion of the test article. There were no treatment-related adverse effects on urinalysis, hematology, serum biochemistry, organ weights, gross and histopathological examination. It was concluded that the no-observed-effect level (NOEL) for L-serine was 3000 mg/kg bw/day for both genders.

Endoscopic submucosal dissection for residual/local recurrence of early gastric cancer after endoscopic mucosal resection.

BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection (EMR) is a widely accepted treatment for early gastric cancer; however, incomplete resection with residual local disease and recurrences continues to be a difficult problem. The aim of this study was to evaluate the efficacy and safety of endoscopic submucosal dissection (ESD) for residual/local recurrent early gastric cancer lesions after EMR. PATIENTS AND METHODS: The en bloc resection rate, histologically complete resection rate, complications, and local recurrence were assessed in 15 patients who underwent ESD for residual/local recurrent early gastric cancer lesions after EMR. RESULTS: The nonlifting sign after injection of a glycerin solution was positive due to scar formation in all cases. En bloc resection was attempted in all cases, with a complete resection rate of 93.3 % (14 of 15). The lesion was completely resected with histologically adequate margins in the 14 patients who received complete en bloc resection. The average operation time was 85.4 +/- 52.9 min, and the mean follow-up period for all patients was 18.1 +/- 7.4 months. Major bleeding during the procedure in one case was the only complication (one of 15, 6.7 %). None of the patients experienced recurrence of early gastric cancer after ESD. CONCLUSIONS: ESD appears to be a safe and effective treatment for residual/local recurrent early gastric cancer lesions after EMR, and it is useful for histological confirmation of successful treatment.

Effect of hollow fiber length on solute removal and quantification of internal filtration rate by Doppler ultrasound.

Renal replacement therapy with dialyzers capable of enhanced internal filtration (IF) can be an alternative to standard hemodiafiltration, as it provides convective solute removal comparable to that of hemodiafiltration by a simple procedure. In this study, we clinically evaluated the effect of the hollow fiber length in the dialyzer, a crucial factor influencing the rate of IF, by comparing two commercial dialyzers (BS-1.6U, BS-1.6UL, Toray, Japan) which differed in the fiber length, but had the same surface area and inner diameter of their hollow fibers. We showed that in the dialyzer with the longer fibers, the pressure profile along the dialyzer was significantly altered, and the solute clearance tended to be increased. In addition, we successfully quantified the IF rate with a Doppler ultrasound in the experimental circuit, by measuring the blood flow velocities along the bundle of fibers. We showed that the changes in the blood flow velocity were more marked in the dialyzer with the longer fibers; the calculated IF rates in the dialyzers with the shorter and longer fibers were 11.1 mL/min and 37.7 mL/min, respectively, which seemed to be compatible with the solute clearances. This simple and readily applicable method is expected to be useful in the development of modified dialyzers to fully exploit the benefits of IF in renal replacement therapy.

A specific brassinosteroid biosynthesis inhibitor, Brz2001: evaluation of its effects on Arabidopsis, cress, tobacco, and rice.

Brassinazole is the only known specific brassinosteroid (BR)-biosynthesis inhibitor, and it has been shown to be useful for elucidating the function of BRs. In the course of a structure-activity relationship study of brassinazole, we found a more specific BR-biosynthesis inhibitor, Brz2001. This new inhibitor induced similar morphological changes to those seen in brassinazole-treated plants, including Arabidopsis thaliana (L.) Heynh., Nicotiana tabacum L., and Lepidium sativum L. These changes included dwarfism with altered leaf morphology, including downward curling and dark-green color, and the changes were reversed by brassinolide. Although the structure of Brz2001 is similar to that of uniconazole, a gibberellin-biosynthesis inhibitor, Brz2001-treated plants showed almost no recovery with the addition of gibberellic acid (GA3). Comparison of the responses of both brassinazole- and Brz2001-treated cress to brassinolide and GA3 suggested that Brz2001 is a more specific BR-biosynthesis inhibitor than brassinazole. Unlike the results just described, Brz2001-treated rice did not show any morphological changes. This suggests that the roles of BRs in rice may be different from those in the dicotyledonous plants examined in this study. Brz2001 can be used to clarify the function of BRs in dicots as a complement to BR-deficient mutants, and to elucidate the different roles of BRs in monocots and dicots.

Drastic neuronal loss in vivo by beta-amyloid racemized at Ser(26) residue: conversion of non-toxic [D-Ser(26)]beta-amyloid 1-40 to toxic and proteinase-resistant fragments.

It is unclear how and when insoluble beta-amyloid in senile plaques exerts degenerative effects on distant hippocampal neurons in Alzheimer's disease. Racemization of Ser and Asp residues of insoluble beta-amyloid is a typical age-dependent process. In this study, we investigated the fibril formation activity and cytotoxic activity of beta-amyloid 1-40 racemized at the Asp or Ser residue. In contrast to beta-amyloid 1-40 and its derivative substituted with the D-Asp(1, 7 or 23) or D-Ser(8) residue, [D-Ser(26)]beta-amyloid 1-40 was non-toxic to PC12 cells, and did not exhibit significant fibril formation activity making it soluble. However, [D-Ser(26)]beta-amyloid 1-40, but not beta-amyloid 1-40, was converted in vitro to a potent neurotoxic and truncated peptide, [D-Ser(26)]beta-amyloid 25-35 or [D-Ser(26)]beta-amyloid 25-40, by chymotrypsin-like enzymes and aminopeptidase M. Soluble [D-Ser(26)]beta-amyloid 1-40 was injected into rat hippocampus with a non-toxic dose of ibotenic acid, an excitatory amino acid. Nissl staining and microtubule-associated protein-2 immunostaining revealed that [D-Ser(26)]beta-amyloid 1-40, as well as [D-Ser(26)]beta-amyloid 25-35, produced a drastic degeneration of the CA1 neurons with ibotenic acid although [D-Ser(26)]beta-amyloid 1-40 alone or ibotenic acid alone did not exert neuronal damage. This suggests the in vivo conversion of non-toxic [D-Ser(26)]beta-amyloid 1-40 to the toxic and truncated peptides which enhance the susceptibility of neurons to the excitatory amino acid.These results and the presence of [D-Ser(26)]beta-amyloid 25-35-like antigens in Alzheimer's disease brains suggest that soluble [D-Ser(26)]beta-amyloid 1-40, possibly formed during the aging process, is released from senile plaques, and converted by brain proteinases to truncated [D-Ser(26)]beta-amyloid 25-35(40)-like peptides, which degenerate hippocampal neurons by enhancing the susceptibility to excitatory amino acids in Alzheimer's disease brains. These findings may provide the basis for a new therapeutic approach to prevent the neurodegeneration in Alzheimer's disease.

Hemodialysis paradox: survey on the incidence rate of hepatocellular carcinoma in antihepatitis virus C-antibody-positive chronic hemodialysis patients.

The prevalence of antihepatitis virus C (HCV) antibodies in chronic hemodialysis (HD) patients is higher than in normal populations, and yet hepatocellular carcinoma (HCC) is infrequent in chronic HD patients who are HCV antibody positive. In this study, we investigated the characteristics of HCV-antibody-positive patients with HCC on chronic HD. A total of 6,366 cases of HCV-antibody-positive patients on chronic HD therapy was analyzed on the basis of answers to questionnaires on the incidence rate of HCC in 314 Japanese dialysis institutions. HCC was a complication in 114 of 6,222 (1.8%) HCV-antibody-positive patients, and cirrhosis was a complication in 536 of 6,242 (8.6%). The incidence rate of both complications was significantly higher in males than in females, and the incidence rate in the chronic HD patients was much lower than in normal populations. Specific immunological status in patients on chronic HD therapy may be an important key for preventing the progression of chronic HCV hepatitis. However, further research is needed because this study was preliminary and excluded the type of HCV virus, pathological findings, and laboratory data.

Effects of operating conditions on selectivity of a plasma fractionator in double filtration plasmapheresis.

In a typical double filtration plasmapheresis treatment, plasma fractionation between albumin and some immunoglobulins associated with toxins is limited because none of the currently available plasma fractionators has a strict cutoff property for these proteins. Selectivity of immunoglobulins over albumin depends not only on the cutoff properties of the membrane but on the operating conditions such as the flow rate of the supplied plasma (Q(P)) and retained plasma to be discarded (Q(D)) in the plasma fractionator. We carried out an in vitro study using human plasma harvested by single plasma exchange treatments to assess the selectivity of a plasma fractionator, Evaflux 2A-F (Kawasumi Laboratories, Inc., Tokyo, Japan), under various operating conditions. The results of rate-constant filtration experiments showed that the concentrations in the feed tank and the sieving coefficient (SC) values of every protein were decreased slightly within 2 h after the start of the experiment because of membrane trapping, adsorption, and/or plugging. The time-averaged SC value of albumin increased with flow rate ratio (Q(P)/Q(D)) due to increasing filtration fraction (FF), but relative removal efficiency (mD/mP*) for albumin decreased with Q(P)/ Q(D) due to decreasing Q(D). For immunoglobulins, on the other hand, the SC values were almost unchanged, and the mD/mP* values increased with Q(P)/Q(D) due to an increase in FF. Both increasing Q(P) and decreasing Q(D) are effective means of improving selectivity between these proteins in the plasma fractionator. Membrane fouling is, however, obvious beyond a Q(P)/Q(D) value that is thought to be a critical point. Operation should be conducted below the critical Q(P)/Q(D) value, which depends on the patient's plasma components and the cutoff property of the membrane.

Mating-type genes from asexual phytopathogenic ascomycetes Fusarium oxysporum and Alternaria alternata.

Mating-type (MAT) loci were cloned from two asexual (mitosporic) phytopathogenic ascomycetes, Fusarium oxysporum (a pyrenomycete) and Alternaria alternata (a loculoascomycete), by a polymerase chain reaction (PCR)-based strategy. The conserved high mobility group (HMG) box domain found in the MAT1-2-1 protein was used as a starting point for cloning and sequencing the entire MAT1-2 idiomorph plus flanking regions. Primer pairs designed to both flanking regions were used to amplify the opposite MAT1-1 idiomorph. The MAT1-1 and MAT1-2 idiomorphs were approximately 4.6 and 3.8 kb in F. oxysporum and approximately 1.9 and 2.2 kb in A. alternata, respectively. In both species, the MAT1-1 idiomorph contains at least one gene that encodes a protein with a putative alpha box domain and the MAT1-2 idiomorph contains one gene that encodes a protein with a putative HMG box domain. MAT-specific primers were used to assess the mating type of F. oxysporum and A. alternata field isolates by PCR. MAT genes from A. alternata were expressed. The A. alternata genes were confirmed to be functional in a close sexual relative, Cochliobolus heterostrophus, by heterologous expression.

Molecular organization of mating type loci in heterothallic, homothallic, and asexual Gibberella/Fusarium species.

Mating type (MAT) genes were cloned from three members of the Gibberella/Fusarium complex that differ in reproductive mode: heterothallic G. fujikuroi, homothallic G. zeae, and asexual F. oxysporum. The G. fujikuroi MAT locus organization is typical of other heterothallic pyrenomycetes characterized to date; i.e., there are three genes at MAT1-1 and one at MAT1-2. G. zeae has homologues of all four genes encoded by the two G. fujikuroi MAT idiomorphs, tightly linked on the same chromosome, interspersed with sequences unique to G. zeae. Field isolates of F. oxysporum, although asexual, have either the MAT1-1 or the MAT1-2 genes found in sexual species and these genes are highly similar to those of heterothallic G. fujikuroi. RT-PCR analysis proved that the F. oxysporum MAT genes are expressed and that all putative introns found in each of the four MAT genes in G. fujikuroi and F. oxysporum are removed. Apparent failure of F. oxysporum to reproduce sexually could not be attributed to mutations in the MAT genes themselves.

Na(+)-Ca(2+) exchanger isoforms in rat neuronal preparations: different changes in their expression during postnatal development.

We examined the relative amounts of Na(+)-Ca(2+) exchanger (NCX) isoform mRNAs in cultured neurons, astrocytes and developmental rat brain. NCX1 transcript was predominant in neurons and astrocytes, but NCX2 transcript was about four-fold higher than NCX1 or NCX3 transcript in adult rat cortex. NCX2 transcript in the cortex increased markedly during postnatal development, whereas NCX1 and NCX3 transcripts decreased. Na(+)-dependent 45Ca(2+) uptake in the cortical homogenate increased significantly during postnatal development.

Can cytokines be removed by hemofiltration or hemoadsorption?

To study the removability of pro-inflammatory cytokines by hemofiltration (HF), we performed experimental HF with various high-flux membranes (HFM) using a closed circuit system filled with monocyte-free human plasma, which contained TNFalpha, IL-1beta, and IL-6. Plasma and filtrate samples were taken before and 1, 2, 3, and 4 hours after the initiation of HF, and each cytokine was determined by enzyme-linked immunosorbent assay. IL-1beta was well removed through filtration during experimental HF using HFM (PAN>CTA>PMMA>PS). TNFalpha and IL-6 were only minimally filtered out by HF using HFM. TNFalpha was removed to some extent by using PS, and IL-6 was partially removed by using PMMA during experimental HF through other mechanisms, such as adsorption, than the filtration. IL-1beta and IL-6 were effectively removed by HA using charcoal adsorbent column, especially during the first 2 hours, while TNFalpha was only partly removed.

Effects of internal filtration on the solute removal efficiency of a dialyzer.

To improve solute removal efficiency, several types of dialyzers with enhanced internal filtration were introduced for clinical application. In these dialyzers, enhanced internal filtration increased convective transport of the solute, in addition to diffusive transport. In this study, the effects of internal filtration on solute removal efficiency were examined by both analytic and experimental studies. Internal filtration is affected by blood (Q(B)) and dialysate (Q(D)) flow rates; the patient's hematocrit and plasma level of total protein; and the effective length (L(eff)), inner diameter (D), and density ratio (DR) of the hollow fibers. An analytic model was introduced for the estimation of the changes in mass and momentum along the dialyzer. It clarified the effects of these parameters on maximum internal filtration flow rate (Q(IF)) and clearance (K) of urea (60 daltons), vitamin B(12) (1,355), and myoglobin (17,000). As a result of the analytic study, Q(IF) was increased, resulting in a smaller D, a longer L(eff), and a larger DR value. Several types of dialyzers with the same cellulose triacetate membrane, produced by Toyobo Co, Ltd., Ohtsu, Japan, and Nissho Corporation, Kusatsu, Japan, were used for the experimental study. An in vitro evaluation using myoglobin solution showed the same trends as found in the analytic study. For example, a dialyzer with 150 microm of D has a 72.0 ml/min myoglobin K value, much higher than that of 53.7 ml/min for a dialyzer with 200 microm of D under constant Q(B) (300 ml/min) and DR (50%) values. Development of a dialyzer with enhanced internal filtration, however, should take the patient's safety into account, and hemolysis and endotoxin invasion from the dialysate to the patient should be avoided.

[Neurotoxicity of beta-amyloid].

Recent observations on the neurotoxicity of beta-amyloid have been reviewed and possible roles of racemization of beta-amyloid are discussed. beta 1-40, beta 25-35 and D-Ser26 beta 25-35 (all HCl salt forms), but not commercially available beta 1-40 (TFA salt form), take the beta-structure within few hours in PBS, form fibrils, exert toxic effects on hippocampal cultured neurons and suppresses MTT reduction activity of non-neuronal HeLa cells without cytotoxicity. D-Ser26 beta 1-40 is soluble and non-toxic in vitro but is converted by brain proteinases to D-Ser26 beta 25-35, a potent toxic and proteinase-resistant fragment. The co-injection of beta 1-40, D-Ser26 beta 25-35 or D-Ser26 beta 1-40 with ibotenic acid, but not beta-amyloid alone or ibotenic acid alone, into rat brains produce drastic neuronal loss in the hippocampal CA1 area. The in vivo degeneration activity of beta-amyloids is well correlated with their having beta-structure and activity to suppress the MTT reduction activity. A specific antibody against D-Ser26 beta 25-35 strongly reacts with hippocampal degenerated-CA1 neurons in AD but not control brains. These results suggest that D-Ser26 beta 25-35 and related peptides possibly generated from insoluble beta 1-40 due to aging exert toxic effects on the hippocampal CA1 pyramidal neurons by enhancing the susceptibility to excitatory amino acids.

REAL, an LTR retrotransposon from the plant pathogenic fungus Alternaria alternata.

A retrotransposon was isolated and characterized from strain 15A of the Japanese pear pathotype of Alternaria alternata, which causes black spot disease in certain cultivars of Japanese pear by producing a host-specific toxin known as AK-toxin. The element, which we have named REAL (Retrotransposon of Alternaria alternata), is 6046 bp in size and contains direct long terminal repeats (LTRs) of 218 bp. Target-site duplication of 5 bp was found. REAL contains two long overlapping ORFs. The first ORF shows homology to retroviral gag genes. The second ORF has homology to protease, reverse transcriptase, RNase H and integrase domains of the retroelement pol genes, in that order. Phylogenetic comparison of reverse transcriptase domains from retrotransposons placed REAL in the Ty3/gypsy group of LTR retrotransposons, most closely related to grasshopper from Magnaporthe grisea. Northern analysis detected REAL transcripts of about 2.0 and 6.0 kb. The 6.0-kb species corresponds to a full-length transcript of the element. The element was found by Southern analysis in 12 out of 13 strains of the Japanese pear pathotype, and the banding patterns, copy numbers and signal intensities in these strains were variable. REAL-related elements were also found in some, but not all, of the other strains tested, including nonpathogenic A. alternata and other pathotypes, which cause diseases on different plant species by producing distinct hostspecific toxins. These results suggest that the distribution of REAL in A. alternata is not pathotype specific.

[Radiosurgery for cystic metastatic brain tumor].

Stereotactic radiosurgery (SRS) for brain metastasis results in a high local control rate. But cystic metastatic tumor should have been a contraindication for SRS. Because it is often found that a cyst is too large to be irradiated, the tumor does not exist in the center of the irradiation field. Between 1995 and 1998, 8 consecutive patients underwent linear accelerator-based SRS for cystic brain metastases identified by computed tomography or magnetic resonance image scan. Stereotactic cyst aspiration is carried out after placement of the BRW frame under local anesthesia. All of the patients except one were confirmed to have sufficient reduction of the cysts. 5-7 days after stereotactic cyst aspiration, SRS was performed. The dose range was 25-30 Gy. In follow-up MRI, local recurrences and enlargement of cysts were not noted. Six patients with neurological symptoms recuperated satisfactorily. Median survival was 30 weeks from the date of radiosurgery. All of the patients died and the causes of death were related with the primary lesion. We conclude that our technique, a combination of stereotactic cyst aspiration and SRS is an effective measure which leads to palliation of neurologic symptoms and is a low risk treatment for patients with cystic brain metastasis.

Solute removal characteristics of continuous recirculating peritoneal dialysis in experimental and clinical studies.

Continuous recirculating peritoneal dialysis (CRPD) was introduced to enhance solute removal efficiency in conventional peritoneal dialysis (PD) therapies such as continuous ambulatory peritoneal dialysis (CAPD). In CRPD, a portion of the dwell dialysate in the patient's peritoneal cavity is drained through a double-lumen catheter and purified by an extracorporeal dialyzer. In this study, solute removal characteristics and safety of CRPD are examined in ex vivo and clinical studies. Recirculation dialysis experiments using nine dogs (13.6 +/- 2.5 kg of body weight) were carried out for 240 min in the ex vivo study, whereas another seven dogs (12.1 +/- 2.8 kg) received conventional peritoneal dialysis (CPD) (120 min dwelling x 2) and six additional dogs (11.9 +/- 2.7 kg) received a Tidal PD (20 min dwelling x 12; 50% of tidal volume ratio) as controls. The ex vivo study revealed that CRPD has a higher efficiency for solute removal than CPD and is equivalent to Tidal PD. In the BUN reduction rate, the 19.4 +/- 5.5% in 240 min CRPD (n = 9) was significantly higher (p < 0.05) than the 3.5 +/- 3.6% in 240 min CPD (n = 7) and equivalent to the 17.3 +/- 4.7% in 240 min Tidal PD (n = 6). Continuous recirculating peritoneal dialysis maintained a low UN level in the peritoneal cavity due to dialysis with an extracorporeal dialyzer. This tendency was also seen in creatinine removal. In the clinical study, CRPD (n = 10) and CPD (n = 5) treatments were used in three renal failure patients. Higher solute removal efficiency was shown in CRPD than in CPD treatments, and the urea peritoneal clearance was 14.1 +/- 4.4 ml/min in CRPD (n = 10), significantly higher (p < 0.05) than the 7.3 +/- 2.1 ml/min in CPD (n = 5). No fibrin formation occurred during CRPD treatments.