non-HS Group Research Articles

Different effect of glutamine on macrophage tumor necrosis factor-alpha release and heat shock protein 72 expression <italic>in vitro</italic> and <italic>in vivo</italic>

Macrophage plays a vital role in sepsis. However, the modulatory effect of glutamine (Gln) on macrophage/ monocyte-mediate cytokines release is still controversial. Thus, we investigated the effect of Gln on macrophage tumor necrosis factor (TNF)-alpha release and heat shock protein (HSP) 72 expression in vivo and in vitro. Data from our study indicated that the increase of HSP72 expression was significant at 8 mM of Gln 4 h after lipopolysaccharide (LPS) stimulation and became independent of Gln concentrations at 24 h, whereas TNF-alpha release was dose- and time-dependent on Gln. Heat stress (HS) induced more HSP72 and less TNF-alpha production compared with the non-HS group. However, the production of TNF-alpha in cells pretreated with HS was increased with increasing concentrations of Gln. Treatment with various concentrations of Gln for 1 h and then 0.5 mM Gln for 4 h led to an increase in HSP72 expression, but not in TNF-alpha production. In sepsis model mice, Gln treatment led to a significantly lower intracellular TNF-alphalevel and an increase in HSP72 expression in mouse peritoneal macrophages. Our results demonstrate that Gln directly increases TNF-alpha release of LPS-stimulated RAW264.7 macrophages in a dose-dependent manner, and also decreases mouse peritoneal macrophages TNF-a release in the sepsis model. Taken together, our data suggest that there may be more additional pathways by which Gln modulates cytokine production besides HSP72 expression in macrophage during sepsis.

The importance of hepatic encephalopathy: Pre-transplant and post-transplant

The importance of hepatic encephalopathy: Pre-transplant and post-transplant

Hemorrhagic transformation of ischemic brain tissue after t-PA thrombolysis as detected by MRI may be asymptomatic, but impair neurological recovery

Background and purpose Symptomatic intracranial hemorrhages are typically clinically catastrophic and occur more frequently with tissue plasminogen activator (t-PA) therapy compared to without t-PA therapy. However, it has been unclear whether asymptomatic intracranial hemorrhage has clinical implications. Methods Consecutive anterior-circulation ischemic stroke patients treated with t-PA within 3 h of stroke onset were studied prospectively. Patients with symptomatic hemorrhages were excluded from the study. To identify the presence of early recanalization and intracranial hemorrhage, as well as to measure infarction volume, MRI examinations, including diffusion-weighted imaging, T2 ⁎, FLAIR, and MRA, were performed before and 1 h, 24 h, and 5–7 days after t-PA thrombolysis. At the same time, serial NIHSS scores were obtained. The independent predictors of dramatic recovery were determined using multivariate logistic regression analysis. Results 51 patients were enrolled in the present study. 22 patients (H group) had an asymptomatic hemorrhage. The NIHSS score of the Non-H group decreased, but that of the H group did not (11.5 ± 6.5 vs. 17.1 ± 6.5 at baseline, and 4.5 ± 6.8 vs. 14.3 ± 7.6 at 7 days; P = 0.0073 for ANOVA). Asymptomatic hemorrhage was more frequently seen in non-dramatic improvement group than in dramatic improvement group (65.5% vs. 13.6%, P = 0.0002). On multivariate logistic regression analysis using the variables that had a P < 0.1 on univariate analysis (AF, baseline NIHSS score, glucose, the presence of asymptomatic hemorrhage, ICA occlusion, early recanalization 1 h after t-PA infusion, and infarction volume 7 days after t-PA therapy), early recanalization (OR: 11.33; 95%CI: 1.064–120.704; P = 0.044) and infarction volume < 100 cm 3 (OR: 13.56; 95%CI: 1.020–180.125; P = 0.048) were independent factors for dramatic improvement, while asymptomatic hemorrhage (OR: 0.03; 95%CI: 0.002–0.537; P = 0.016) was an independent negative factor. Conclusion Asymptomatic hemorrhage was an independent negative factor for dramatic improvement. Asymptomatic hemorrhage after t-PA thrombolysis may be associated with neurological recovery.

Association of the ε2 Allele of Apoe Gene to Hypertriglyceridemia and to Early‐Onset Alcoholic Cirrhosis

The diverse incidence of alcoholic cirrhosis around the world and the fact that not all alcoholic drinkers develop liver disease indicates that genetic and environmental factors play an important role in the development of liver cirrhosis. Lipids participate in early stages of alcoholic cirrhosis. Therefore variations in the plasma lipid profile due to primary (genetic) or secondary (environmental) dyslipidemia could affect the development of liver disease. The aim of this study was to analyze the lipid profile and apolipoprotein E (APOE) polymorphism in patients with alcoholic liver cirrhosis (AC) and determine the risk associated with genotype polymorphism with the onset of alcoholic cirrhosis. In a case and control study, 86 patients with AC divided into hyperlipidemic (H) and non-hyperlipidemic (non-H) groups, and 133 healthy individuals (C) matched by age and sex were studied. Lipid profile and liver function tests were measured by enzymatic methods. The APOE genotypes were identified by PCR-RFLP's. A statistically significant increase of the APOE*2 allele and genotypes 2/2, 2/3, and 2/4 was present in AC patients compared to C group. A hyperlipidemic state characterized by increased levels of triglycerides and apolipoprotein B (APOB) and a decrease of high density lipoprotein-cholesterol (HDL-c) was detected in young-aged patients (31.2 +/- 6.2 years old vs. 46.3 +/- 12.5 years old). In this group, hypertriglyceridemia was closely associated to APOE*2 allele and to an early onset of liver cirrhosis. By contrast, APOE*4 allele was associated with a longer duration of alcohol intake (>20 years) in the non-H group. This study shows the association of hypertriglyceridemia and APOE allele with the early onset of alcoholic liver cirrhosis, and the interaction between environmental factors, such as duration of alcohol abuse and amount of alcohol intake, and genetic factors (APOE*2 allele) on the hypertriglyceridemic process.

Altered expression of 3-containing GABAA receptors in the neocortex of patients with focal epilepsy

Impaired transmission in GABAergic circuits is thought to contribute to the pathogenesis of epilepsy. Although it is well established that major reorganization of GABA(A) receptor subtypes occurs in the hippocampus of patients with medically refractory temporal lobe epilepsy (TLE), it is unclear whether this disorder is also associated with alterations in GABA(A) receptor subtypes in the neocortex. Here we have investigated immunohistochemically the subunit composition and neocortical distribution of three major GABA(A) receptor subtypes using antibodies specifically recognizing the subunits alpha1, alpha2, alpha3, beta2/3 and gamma2. Cortical tissue was obtained at surgery from patients with TLE and hippocampal sclerosis (HS; n = 9), TLE associated with neocortical lesions (non-HS; n = 12) and frontal lobe epilepsy (FLE; n = 5), with post-mortem samples serving as controls (n = 4). A distinct laminar and neuronal expression pattern of the alpha-subunit variants was found across the neocortical regions examined in the temporal and frontal lobes in both control and patient tissue samples. In the five patients with FLE, GABA(A) receptor subunit staining was unchanged as compared to controls. In patients with TLE we observed a marked decrease in alpha3-subunit staining in the superficial neocortical layers (I-III), but no change in the deep layers (V and VI) or in the expression pattern of the alpha1 and alpha2-subunits. Reduced expression in alpha3-containing GABA(A) receptors was detected in six out of nine patients of the HS group and four out of twelve patients of the non-HS group. Histopathological changes were present in eight out of the ten patients with decreased alpha3-subunit staining. The selective reduction in alpha3-containing GABA(A) receptors was confirmed using semiquantitative measurements of optical density (OD). The specific changes unique to alpha3-subunit expression in the superficial neocortical layers of patients with TLE suggest that this subtype is of particular significance in the reorganization of cortical GABAergic systems in focal epilepsy.

Asociación de la región microsatélite AGAT del gen receptor de mineralocorticoides con los niveles de actividad renina en hipertensos esenciales

Hypertensive states could result from constitutive activation of mineralorticoid receptor (MR) that generates salt retention and blood pressure elevation. Moreover, microsatellite regions can be associated to the regulation of the gene expression, producing subtle pathologies. To determine the influence of microsatellite marker AGAT of the mineralocorticoid receptor gene in the plasma renin activity (PRA) and serum aldosterone (SA) levels of essential hypertensives (HT). We studied 292 HT patients and 57 normotensive (NT) controls. Blood samples were collected for PRA, SA and DNA isolation. Subjects were genotyped according to the length of the tetranucleotide AGAT repeat using polymerase chain reaction and polyacrylamide gel electrophoresis. Based on the normal distribution, we considered 13 to 15 repeats as a habitual (H) length and less than 13 or more than 15 repeats, as non-habitual (non-H). We detected 8 different lengths in the AGAT repeat (allele) in both groups, ranging from 9-17 repeats, where the allele 11 was not detected in either hypertensive or normotensive groups. The allelic distribution was different in both groups (c2 =37.57, 4GL, p <0.001). In hypertensive patients, the H group showed higher PRA levels (median (Q1-Q3)) than the non-H group: 1.3 (0-7-3.5) vs 1.0 (0.5-2.3) ng/mL*h, p <0.05. The SA levels did not show differences between both groups, but the SA*PRA product was higher in the H group than the no-H group: 9.3 (3.0-24.6) vs 6.5 (2.5-14.6) p <0.05. In normotensive patients, no differences were observed in PRA, SA and SA*PRA between both groups. These results show association between the length of the AGAT repeat with the PRA in HT, suggesting a plausible role in the control of the MR gene expression, and secondarily in the regulation of blood pressure.

Up-regulation of hippocampal metabotropic glutamate receptor 5 in temporal lobe epilepsy patients

Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors involved in the regulation of glutamatergic transmission. Recent studies indicate that excitatory group I mGluRs (mGluR1 and mGluR5) contribute to neurotoxicity and hyperexcitability during epileptogenesis. In this study, we examined the distribution of mGluR1alpha and mGluR5 immunoreactivity (IR) in hippocampal resection tissue from pharmaco-resistant temporal lobe epilepsy (TLE) patients. IR was detected with panels of receptor subtype specific antisera in hippocampi from TLE patients without (non-HS group) and with hippocampal sclerosis (HS group) and was compared with that of non-epileptic autopsy controls (control group). By immunohistochemistry and immunoblot analysis, we found a marked increase of mGluR5 IR in hippocampi from the non-HS compared with the control group. High mGluR5 IR was most prominent in the cell bodies and apical dendrites of hippocampal principal neurons and in the dentate gyrus molecular layer. In the HS group, this increase in neuronal mGluR5 IR was even more pronounced, but owing to neuronal loss the number of mGluR5-immunoreactive neurons was reduced compared with the non-HS group. IR for mGluR1alpha was found in the cell bodies of principal neurons in all hippocampal subfields and in stratum oriens and hilar interneurons. No difference in mGluR1alpha IR was observed between neurons in both TLE groups and the control group. However, owing to neuronal loss, the number of mGluR1alpha-positive neurons was markedly reduced in the HS group. The up-regulation of mGluR5 in surviving neurons is probably a consequence rather than a cause of the epileptic seizures and may contribute to the hyperexcitability of the hippocampus in pharmaco-resistant TLE patients. Thus, our data point to a prominent role of mGluR5 in human TLE and indicate mGluR5 signalling as potential target for new anti-epileptic drugs.

Reduced glutamine synthetase in hippocampal areas with neuron loss in temporal lobe epilepsy

Increased levels of glutamate have been reported in the epileptogenic hippocampus of patients with temporal lobe epilepsy (TLE). This sustained increase, which may contribute to the initiation and propagation of seizure activity, indicates impaired clearance of glutamate released by neurons. Glutamate is predominantly cleared by glial cells through the excitatory amino acid transporter 2 (EAAT2) and its subsequent conversion to glutamine by the glial enzyme glutamine synthetase (GS). The authors examined the hippocampal distribution of GS, EAAT2, and glial fibrillary acidic protein (GFAP) by immunohistochemistry in TLE patients with (HS group) and without hippocampal sclerosis (non-HS group), and in autopsy controls. In hippocampal homogenates the authors measured relative protein amounts by immunoblotting and GS enzyme activity. In the autopsy control and non-HS group GS immunoreactivity (IR) was predominantly found in glia in the neuropil of the subiculum, of the pyramidal cell layer of all CA fields, and in the supragranular layer of the dentate gyrus. In the HS group, GS and EAAT2 IR were markedly reduced in subfields showing neuron loss (CA1 and CA4), whereas GFAP IR was increased. The reduction in GS IR in the HS group was confirmed by immunoblotting and paralleled by decreased GS enzyme activity. Glial glutamine synthetase is downregulated in the hippocampal sclerosis (HS) hippocampus of temporal lobe epilepsy (TLE) patients in areas with severe neuron loss. This downregulation appears to be pathology-related, rather than seizure-related, and may be part of the mechanism underlying impaired glutamate clearance found in the hippocampus of TLE patients with HS.

Cup-to-disc ratio, intraocular pressure, and primary open-angle glaucoma in retinal venous occlusion

Purpose To investigate the association of cup-to-disc ratio (CDR), intraocular pressure (IOP), and primary open-angle glaucoma (POAG) with the site of retinal venous occlusion (RVO) and optic nerve head swelling (ONHS). Design Prospective observational case series. Participants Four hundred fifty consecutive cases from a single tertiary referral center. Methods Fundus photography of the retinopathy, 30° stereo photography of the optic disc, and Goldmann applanation tonometry were the main parameters studied. The diagnosis of POAG was obtained from the referring ophthalmologist. Main outcome measures The main outcome measures were the CDR, measured vertically through the center of the optic disc, and the site of RVO, identified as an arteriovenous (AV) crossing, optic cup, or optic nerve. Retinal venous occlusions occurring within the optic nerve were subdivided on the basis of the presence or absence of ONHS. Results There were poor correlations between CDR and IOP ( r = 0.18; P = 0.000209) and CDR and age ( r = 0.21; P = 0.000012). There were 197 AV crossing-sited RVOs (AV-RVOs) (43.8%) and 46 optic cup (OC)-sited RVOs (10.2%). The remainder occurred within the optic nerve; the ONHS group had 80 cases (17.8%) and the nonoptic nerve head swelling group (NONHS) had 127 cases (28.2%). The OC-RVO group tended to be the oldest of the four groups, whereas the ONHS group was the youngest ( P < 0.000001). The mean CDR was significantly higher in the OC-RVO (0.65) compared with the rest of the groups (0.45–0.48). The proportion of cases with CDR ≥ 0.7 was significantly higher in the OC-RVO group (39.1%) compared with the rest of the groups (0–6.3%). There was a trend ( P = 0.000012) for IOP in the OC-RVO group (19.0 mmHg) and NONHS group (17.6 mmHg); the proportion of cases with IOP more than 21 mmHg was also higher in these cases ( P = 0.00033). The prevalence of POAG was highest ( P < 0.000001) in the OC-RVO group (39.1%) followed by the NONHS group (18.1%), ONHS group (8.8%), and AV-RVO (4.1%) group, respectively. Conclusions Optic cup and optic nerve-sited RVO without ONHS are associated with raised IOP and may share a common management strategy aimed at controlling ocular pressure. Glaucomatous optic disc cupping, in contrast, seems to be important in the OC-sited RVO group only. Intraocular pressure, POAG, and glaucomatous optic disc cupping do not significantly seem to contribute to the development of RVO at an AV crossing or when the occlusion occurs within the optic nerve in association with ONHS.

Distribution of glutamate transporters in the hippocampus of patients with pharmaco-resistant temporal lobe epilepsy.

In patients suffering from temporal lobe epilepsy (TLE), increased extracellular glutamate levels in the epileptogenic hippocampus both during and after clinical seizures have been reported. These increased glutamate levels could be the result of malfunctioning and/or downregulation of glutamate transporters (also known as EAATs; excitatory amino acid transporters). In this study, the distribution of protein and mRNA of EAAT subtypes was examined in the hippocampus of TLE patients with hippocampal sclerosis (HS group) and without hippocampal sclerosis (non-HS group), and in autopsy controls without neurological disorders. EAAT protein localization was studied by immunohistochemistry on paraffin sections using specific poly- and monoclonal antibodies against the glial glutamate transporters EAAT1 and EAAT2 and the neuronal glutamate transporter EAAT3. Antibody specificity was shown by immunoblotting. In the HS group, a small decrease in EAAT1-immunoreactivity (IR) was observed in CA4 and in the polymorphic and supragranular layer of the dentate gyrus, compared with the control group. The strongest changes were found for EAAT2 levels. In the non-HS group, increased EAAT2-IR was detected in the CA1 and CA2 field, compared with non-epileptic controls. EAAT2-IR was decreased in the HS compared with the non-HS group. Fewer EAAT3-positive cells were found in the HS group than in the non-HS and control group. In both TLE groups, increased EAAT3 levels were observed in individual neurones. In the HS group, the percentage of EAAT3-IR neurones was increased in CA2 and in the granule cell layer of the dentate gyrus. Radioactive in situ hybridization for EAAT1-3 confirmed our immunohistochemical results. Non-radioactive in situ hybridization showed that not only astrocytes, but also neurones express EAAT2 mRNA. Taken together, differences in both mRNA and protein levels of glutamate transporter subtypes were found in specific regions in the TLE hippocampus, with most severe changes found for EAAT2 and EAAT3 levels. The results indicate an upregulation of EAAT2 protein expression in CA1 and CA2 in neurones in the non-HS group. This is in line with decreased EAAT2 protein levels in the HS group, since these hippocampi are characterized by severe neuronal cell loss. The functional consequences (glutamate transport capacity) of the reported changes in EAAT2 and EAAT3 remain to be determined.

Role of KATP channel in heat shock and pharmacological preconditioning.

Heat shock (HS) and 4-monophosphoryl lipid A (MLA, a non-toxic analogue of endotoxin) protects the myocardium against ischemia-reperfusion injury. We studied the involvement of ATP-sensitive potassium channel (KATP channel) in ischemic protection induced by these stimuli. Anesthetized rabbits were preconditioned with either HS (by raising temperature to 42 degrees C for 15 min) or intravenous pretreatment with MLA (35 micrograms/kg). After 24 h, animals were re-anesthetized and subjected to 30-min regional ischemia followed by 180-min reperfusion (I/R). KATP channel blockers glibenclamide and/or 5-hydroxydecanoate (5-HD) were used to inhibit channel function. The 72 kD heat shock protein (HSP-72) was measured by Western blots. HS produced a marked reduction in infarct size (39.4 +/- 8.1% to 14.3 +/- 2.5%, p < 0.05) that was abolished by glibenclamide (42.3 +/- 3.2%) and 5-HD (33.7 +/- 4.8%) when given before I/R. These drugs failed to block HS protection when given before HS. Expression of HSP-72 was increased in all HS groups as compared to non-HS groups in both glibenclamide and 5-HD-treated rabbits. Similarly, pretreatment with MLA reduced infarct size from 40 +/- 8.6% to 15.1 +/- 1.5% (p < 0.05). The infarct size increased to 51.9 +/- 5.8 with 5-HD in MLA-treated rabbits. 5-HD did not alter infarct size significantly when given in vehicle-treated control rabbits. These data suggest that HS and MLA exert their anti-ischemic effect through activation of KATP channel.

Heat stress produces an early phase of protection against oxidative damage in human muscle

It has been rarely reported that heat stress induces an early phase of protection against oxidative damage, whereas a delayed phase of protection is shown in heat stress. To explore the early effect of heat stress against oxidative damage, we evaluated the changes in contractility, lipid peroxidation, and ultrastructure induced by hydrogen peroxide (H2O2) with or without heat stress (HS) in human skeleton muscle. Thirty-two muscle samples were obtained from the vastus lateralis muscle of 7 subjects. These specimens were divided into three groups based on form of treatment: HS (n = 13), non HS (n = 14), and control group (n = 5). The control group was performed under identical conditions without H2O2. Specimens in the HS group were incubated at 42 degrees C for 20 min, while those in the non-HS and control groups were maintained at 37 degrees C. The control group showed no significant change in contractile force. Although contractile force significantly decreased 30 min after H2O2 administration in both the HS and non-HS groups, only the HS group showed apparent recovery of contractile force 60 min after H2O2 administration. Lipid peroxidation was lower in the HS group than in the non-HS group. Ultrastructural examination revealed less mitochondrial damage in the HS group compared with the non-HS group. We found that human skeleton muscle escaped cellular damage induced by H2O2 in the early phase after heat stress. These data suggest evidence for an early effect of heat stress against ischemia/reperfusion injury in human muscle.

Prediction of Hepatic Encephalopathy in Paracetamol Overdose: A Prospective and Validated Study

Background: Paracetamol overdose may cause hepatic encephalopathy (HE). This condition demands specialized care and, in some instances, liver transplantation evaluation. No model is available for predicting HE. We aimed to set up and validate a model for predicting the occurrence of HE in paracetamol overdose. Methods: Prospectively, 161 patients with single-dose paracetamol overdose and no HE (defined as hepatic coma grade II or more) on admission were studied during a 26-month period. Patients admitted during the first 13-month period constituted a learning set to construct a model to predict the occurrence of HE. Patients admitted in the second 13-month period constituted the validation set. Serial biochemical variables (measured twice daily), the time line after the overdose, and demographic data were used for univariate testing, and significant factors were assessed in various multiple logistic regression analyses. Results: Thirty-two patients (20%), 15 in the first period and 17 in the second, developed HE grade II. The best model (the highest chi-square) for HE included: log10 (hours from overdose to antidote treatment), log10 (plasma coagulation factors on admission), and platelet count · hours from overdose (chi-square = 41.2, P < 0.00001). In the validation set 88% (confidence interval (CI), 64%-99%) of the patients who developed HE were correctly predicted by the constructed model, whereas 90% (CI, 79%-96%) of the patients in the non-HE group were correctly predicted. Conclusions: The constructed model for predicting HE in paracetamol overdose proved sensitive and accurate in the validation set and should be valuable for transferring high-risk patients to a liver intensive care unit/transplantation facility.

Increased densities of AMPA GluR1 subunit proteins and presynaptic mossy fiber sprouting in the fascia dentata of human hippocampal epilepsy

In human hippocampal epilepsy, there is a consistent pathology of cell loss and reactive synaptic reorganization of `excitatory' mossy fibers (MF) into the inner molecular layer (IML) of the fascia dentata (FD). In this study, neo-Timm's histochemistry of MFs and immunocytochemistry of GluR1 were used to determine, in patients with or without hippocampal sclerosis (HS), if there was a correlation between aberrant supragranular (IML) mossy fiber sprouting and increased densities of AMPA GluR1 subunit proteins in the IML of the FD. Computerized quantified densitometric grey values of Timm and GluR1 densities were corrected for the densities of granule cell losses using cell counts. In the IML of the HS group, despite the losses of granule cells, mossy fiber sprouting was significantly greater ( P<0.000001) and GluR1 protein densities were significantly higher ( P<0.0005) than those of the non-HS group. Unlike supragranular mossy fiber sprouting, which was limited to the IML, the increased GluR1 stainings were distributed throughout the whole molecular layer. For all cases, MF synaptic reorganization in the supragranular ML was correlated with GluR1 subunit protein densities in the IML ( R=0.784, P<0.0093). These data demonstrate that in the human epileptic fascia dentata, there are significantly increased AMPA GluR1 subunit proteins associated with aberrant MF synaptic reorganizations. This suggests that the hyperexcitability of sclerotic hippocampus occurs, at least in part, from the associated changes of both presynaptic mossy fiber glutamatergic neoinnervation and increased GluR1 subunit proteins in the dendritic domains of the FD.

Prevention of Hypovolemia-Induced Hypotension during Hemodialysis by Means of an Optical Reflection Method

In this study protocol we evaluate the clinical value of the continuous monitoring of blood volume (BV) during hemodialysis (HD) by means of an optical reflection method. In the course of a dialysis session the ratio between the ultrafiltration (UF) rate and the patient's refill capacity determines the extent of decrease of BV. A steep fall of BV and, moreover, a remaining absolute BV too low, cause the greater part of hemodialysis-induced complaints. During 23 standard HD sessions BV was monitored by means of the optical method. Nine of the sessions were complicated by hypotension (group H). Comparison of the mean BV graphs of group H with the graphs of non-complicated sessions (non-H) produces several differences. Most important is the fact that BV is better preserved in group non-H, a difference which is already significant during the first ninety minutes of dialysis. By making use of the shape of the monitored BV graph and HD patient, in that way, might be recognized as hypotension-prone during the first third of a dialysis session. To prevent the occurrence of hypovolemia-induced hypotension two strategies can be followed. First, the decrease of BV of a patient prone to hypotension can be triggered to the mean BV decrease according to the BV graph of the non-H group. This can be achieved by interventional methods, e.g. temporary lowering of the UF rate. However, for this intervention the development of a closed-loop circuit is required. Another possibility is to measure a patient's maximal refill capacity each hour of hemodialysis by taking advantage of the displayed BV graph.(ABSTRACT TRUNCATED AT 250 WORDS)