Theta oscillons in behaving rats

Recently discovered constituents of the brain waves-the oscillons -provide high-resolution representation of the extracellular field dynamics. Here we study the most robust, highest-amplitude oscillons that manifest in actively behaving rats and generally correspond to the traditional θ -waves. We show that the resemblances between θ -oscillons and the conventional θ -waves apply to the ballpark characteristics-mean frequencies, amplitudes, and bandwidths. In addition, both hippocampal and cortical oscillons exhibit a number of intricate, behavior-attuned, transient properties that suggest a new vantage point for understanding the θ -rhythms' structure, origins and functions. We demonstrate that oscillons are frequency-modulated waves, with speed-controlled parameters, embedded into a noise background. We also use a basic model of neuronal synchronization to contextualize and to interpret the observed phenomena. In particular, we argue that the synchronicity level in physiological networks is fairly weak and modulated by the animal's locomotion.

Theta oscillons in behaving rats

Recently discovered constituents of the brain waves-the oscillons-provide high-resolution representation of the extracellular field dynamics. Here we study the most robust, highest-amplitude oscillons that manifest in actively behaving rats and generally correspond to the traditional θ -waves. We show that the resemblances between θ -oscillons and the conventional θ -waves apply to the ballpark characteristics-mean frequencies, amplitudes, and bandwidths. In addition, both hippocampal and cortical oscillons exhibit a number of intricate, behavior-attuned, transient properties that suggest a new vantage point for understanding the θ -rhythms' structure, origins and functions. We demonstrate that oscillons are frequency-modulated waves, with speed-controlled parameters, embedded into a noise background. We also use a basic model of neuronal synchronization to contextualize and to interpret the observed phenomena. In particular, we argue that the synchronicity level in physiological networks is fairly weak and modulated by the animal's locomotion.

Altered patterning of neural activity in a tauopathy mouse model

Alzheimer's disease (AD) is a complex neurodegenerative condition that manifests at multiple levels and involves a spectrum of abnormalities ranging from the cellular to cognitive. Here, we investigate the impact of AD-related tau-pathology on hippocampal circuits in mice engaged in spatial navigation, and study changes of neuronal firing and dynamics of extracellular fields. While most studies are based on analyzing instantaneous or time-averaged characteristics of neuronal activity, we focus on intermediate timescales-spike trains and waveforms of oscillatory potentials, which we consider as single entities. We find that, in healthy mice, spike arrangements and wave patterns (series of crests or troughs) are coupled to the animal's location, speed, and acceleration. In contrast, in tau-mice, neural activity is structurally disarrayed: brainwave cadence is detached from locomotion, spatial selectivity is lost, the spike flow is scrambled. Importantly, these alterations start early and accumulate with age, which exposes progressive disinvolvement the hippocampus circuit in spatial navigation. These features highlight qualitatively different neurodynamics than the ones provided by conventional analyses, and are more salient, thus revealing a new level of the hippocampal circuit disruptions.

Phase I dose escalation and expansion study of golidocitinib, a highly selective JAK1 inhibitor, in relapsed or refractory peripheral T-cell lymphomas

BACKGROUND

Relapsed or refractory peripheral T-cell lymphomas (r/r PTCLs) are a group of rare and aggressive diseases that lack effective therapies. Constitutive activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is reported to be associated with PTCLs. Golidocitinib is an oral, potent JAK1 selective inhibitor evaluated in a phase I/II multinational study in patients with r/r PTCLs.

PATIENTS AND METHODS

Patients with r/r PTCLs were eligible. The primary objectives were to assess safety and tolerability of golidocitinib and to define its recommended phase II dose (RP2D). The secondary objectives were to evaluate its antitumor activity and pharmacokinetics (PK).

RESULTS

A total of 51 patients were enrolled and received golidocitinib treatment at 150 or 250 mg once daily (QD). The median prior lines of therapies were 2 (range: 1-8). Golidocitinib was tolerated at both doses tested, while a higher incidence of serious adverse events and dose modifications at 250 mg were observed. The most common grade ≥3 drug-related treatment-emergent adverse events were neutropenia (27.5%) and thrombocytopenia (11.8%). An objective response rate of 39.2% and a complete response rate of 21.6% were observed. With median follow-up time of 14.7 and 15.9 months, the median duration of response (DoR) and progression-free survival were 8.0 and 3.3 months, respectively. Based on these data, 150 mg QD was defined as the RP2D. Golidocitinib demonstrated a favorable PK profile as an oral agent. Biomarker analysis suggested a potential correlation between JAK/STAT pathway aberrations and clinical activity of golidocitinib.

CONCLUSIONS

In this phase I study, golidocitinib demonstrated an acceptable safety profile and encouraging antitumor efficacy in heavily pretreated patients with r/r PTCLs. These results support the initiation of the multinational pivotal study in patients with r/r PTCLs.

Histone H3 lysine 27 crotonylation mediates gene transcriptional repression in chromatin

Histone lysine acylation, including acetylation and crotonylation, plays a pivotal role in gene transcription in health and diseases. However, our understanding of histone lysine acylation has been limited to gene transcriptional activation. Here, we report that histone H3 lysine 27 crotonylation (H3K27cr) directs gene transcriptional repression rather than activation. Specifically, H3K27cr in chromatin is selectively recognized by the YEATS domain of GAS41 in complex with SIN3A-HDAC1 co-repressors. Proto-oncogenic transcription factor MYC recruits GAS41/SIN3A-HDAC1 complex to repress genes in chromatin, including cell-cycle inhibitor p21. GAS41 knockout or H3K27cr-binding depletion results in p21 de-repression, cell-cycle arrest, and tumor growth inhibition in mice, explaining a causal relationship between GAS41 and MYC gene amplification and p21 downregulation in colorectal cancer. Our study suggests that H3K27 crotonylation signifies a previously unrecognized, distinct chromatin state for gene transcriptional repression in contrast to H3K27 trimethylation for transcriptional silencing and H3K27 acetylation for transcriptional activation.

Suvemcitug as second-line treatment of advanced or metastatic solid tumors and with FOLFIRI for pretreated metastatic colorectal cancer: phase Ia/Ib open label, dose-escalation trials

BACKGROUND

Suvemcitug (BD0801), a novel humanized rabbit monoclonal antibody against vascular endothelial growth factor, has demonstrated promising antitumor activities in preclinical studies.

PATIENTS AND METHODS

The phase Ia/b trials investigated the safety and tolerability and antitumor activities of suvemcitug for pretreated advanced solid tumors and in combination with FOLFIRI (leucovorin and fluorouracil plus irinotecan) in second-line treatment of metastatic colorectal cancer using a 3 + 3 dose-escalation design. Patients received escalating doses of suvemcitug (phase Ia: 2, 4, 5, 6, and 7.5 mg/kg; phase Ib: 1, 2, 3, 4, and 5 mg/kg plus FOLFIRI). The primary endpoint was safety and tolerability in both trials.

RESULTS

All patients in the phase Ia trial had at least one adverse event (AE). Dose-limiting toxicities included grade 3 hyperbilirubinemia (one patient), hypertension and proteinuria (one patient), and proteinuria (one patient). The maximum tolerated dose was 5 mg/kg. The most common grade 3 and above AEs were proteinuria (9/25, 36%) and hypertension (8/25, 32%). Forty-eight patients (85.7%) in phase Ib had grade 3 and above AEs, including neutropenia (25/56, 44.6%), reduced leucocyte count (12/56, 21.4%), proteinuria (10/56, 17.9%), and elevated blood pressure (9/56, 16.1%). Only 1 patient in the phase Ia trial showed partial response, [objective response rate 4.0%, 95% confidence interval (CI) 0.1% to 20.4%] whereas 18/53 patients in the phase Ib trial exhibited partial response (objective response rate 34.0%, 95% CI 21.5% to 48.3%). The median progression-free survival was 7.2 months (95% CI 5.1-8.7 months).

CONCLUSIONS

Suvemcitug has an acceptable toxicity profile and exhibits antitumor activities in pretreated patients with advanced solid tumors or metastatic colorectal cancer.

Structural mechanism of BRD4-NUT and p300 bipartite interaction in propagating aberrant gene transcription in chromatin in NUT carcinoma

BRD4-NUT, a driver fusion mutant in rare and highly aggressive NUT carcinoma, acts in aberrant transcription of anti-differentiation genes by recruiting histone acetyltransferase (HAT) p300 and promoting p300-driven histone hyperacetylation and nuclear condensation in chromatin. However, the molecular basis of how BRD4-NUT recruits and activates p300 remains elusive. Here, we report that BRD4-NUT contains two transactivation domains (TADs) in NUT that bind to the TAZ2 domain in p300. Our NMR structures reveal that NUT TADs adopt amphipathic helices when bound to the four-helical bundle TAZ2 domain. The NUT protein forms liquid-like droplets in-vitro that are enhanced by TAZ2 binding in 1:2 stoichiometry. The TAD/TAZ2 bipartite binding in BRD4-NUT/p300 triggers allosteric activation of p300 and acetylation-driven liquid-like condensation on chromatin that comprise histone H3 lysine 27 and 18 acetylation and transcription proteins BRD4L/S, CDK9, MED1, and RNA polymerase II. The BRD4-NUT/p300 chromatin condensation is key for activating transcription of pro-proliferation genes such as ALX1, resulting ALX1/Snail signaling and epithelial-to-mesenchymal transition. Our study provides a previously underappreciated structural mechanism illuminating BRD4-NUT's bipartite p300 recruitment and activation in NUT carcinoma that nucleates a feed-forward loop for propagating histone hyperacetylation and chromatin condensation to sustain aberrant anti-differentiation gene transcription and perpetual tumor cell growth.

Structural insight into ASH1L PHD finger recognizing methylated histone H3K4 and promoting cell growth in prostate cancer

ASH1L is a member of the Trithorax-group protein and acts as a histone methyltransferase for gene transcription activation. It is known that ASH1L modulates H3K4me3 and H3K36me2/3 at its gene targets, but its specific mechanism of histone recognition is insufficiently understood. In this study, we found that the ASH1L plant homeodomain (PHD) finger interacts with mono-, di-, and trimethylated states of H3K4 peptides with comparable affinities, indicating that ASH1L PHD non-selectively binds to all three methylation states of H3K4. We solved nuclear magnetic resonance structures picturing the ASH1L PHD finger binding to the dimethylated H3K4 peptide and found that a narrow binding groove and residue composition in the methylated-lysine binding pocket restricts the necessary interaction with the dimethyl-ammonium moiety of K4. In addition, we found that the ASH1L protein is overexpressed in castrate-resistant prostate cancer (PCa) PC3 and DU145 cells in comparison to PCa LNCaP cells. The knockdown of ASH1L modulated gene expression and cellular pathways involved in apoptosis and cell cycle regulation and consequently induced cell cycle arrest, cell apoptosis, and reduced colony-forming abilities in PC3 and DU145 cells. The overexpression of the C-terminal core of ASH1L but not the PHD deletion mutant increased the overall H3K36me2 level but had no effect on the H3K4me2/3 level. Overall, our study identifies the ASH1L PHD finger as the first native reader that non-selectively recognizes the three methylation states of H3K4. Additionally, ASH1L is required for the deregulation of cell cycle and survival in PCas.

[Berberine inhibits erastin-induced ferroptosis of mouse hippocampal neuronal cells possibly by activating the Nrf2-HO-1/GPX4 pathway]

OBJECTIVE

To explore the mechanism by which berberine inhibits ferroptosis of mouse hippocampal neuronal cells (HT22).

METHODS

Cultured HT22 cells were pretreated with 30 or 60 μmol/L berberine for 2 h before exposure to 0.5 μmol/L erastin for 8 h, and the cell proliferation, intracellular ferric iron level, changes in intracellular reactive oxygen species (ROS) and cell apoptosis were detected using CCK-8, Fe²⁺ fluorescent probe, fluorescent dye (DAPI) and fluorescent probe (H2DCFH-DA). RT-qPCR and Western blotting were used to detect the mRNA and protein expressions of Nrf2, HO-1 and GPX4 in the cells. We further tested the effects of treatments with 2 μmol/L ML385 (a Nrf2 inhibitor), 60 μmol/L berberine and erastin in the cells to explore the protective mechanism of berberine against erastin-induced ferroptosis in the neuronal cells.

RESULTS

Treatment with 0.5 μmol/L erastin significantly lowered the viability of HT22 cells (P < 0.05) and increased the production of ROS, cell apoptosis rate and ferric iron level (P < 0.05). Pretreatment with 30 and 60 μmol/L berberine both significantly increased the vitality of erastin-exposed cells (P < 0.05) and lowered the levels of intracellular ROS and ferric iron content (P < 0.05). RT-qPCR and Western blotting showed that berberine obviously promoted the expressions of Nrf2, HO-1 and GPX4 in the cells (P < 0.05), and treatment with ML385 significantly inhibited the Nrf2-HO-1/GPX4 pathway, increased intracellular ROS and ferric iron contents and mitigated the protective effect of berberine against erastin-induced ferroptosis (P < 0.05).

CONCLUSION

Berberine can inhibit erastin-induced ferroptosis in HT22 cells possibly by activating the Nrf2-HO-1/ GPX4 pathway.

The role of inflammation and cortisol in the relationship between social cognition abilities and later emotional or behavioural problems: evidence from a UK birth cohort

Introduction

Deficits in social cognition have been associated with the onset of emotional and behavioural problems, but the biological mechanisms underlying this relationship remain unclear.

Objectives

This study examined whether diurnal cortisol patterns, systemic inflammation, or both, explained the association between social cognition difficulties and subsequent emotional and behavioural symptoms.

Methods

The sample consisted of 714 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC) with valid data on cortisol measures (age 15 years) and emotional or behavioural problems (age 17 years). Social cognition abilities were measured at 8, 11, and 14 years old. Inflammation was measured using serum levels of interleukin 6 (IL-6, age 9 years) and C-reactive protein (CRP, age 9 and 16 years). Bayesian structural equation modelling was used to investigate the mediating effect of cortisol or inflammation on the association between social cognitive difficulties and emotional or behavioural problems.

Results

Children with social cognition difficulties were associated with later emotional and behavioural problems. Flattened diurnal cortisol slope was associated with the hyperactivity/inattention problem two years later. Mediation analyses revealed that lower morning cortisol significantly mediated the associations between social communication difficulties at 8 years with hyperactivity/inattention and conduct problems in adolescence, with the adjustment of inflammation and all covariates. Systemic inflammation was not related to social cognitive difficulties or future emotional and behavioural problems.

Conclusions

The finding suggests that social cognition is related to cortisol activities longitudinally. It also expands the evidence that adolescents with behavioural problems are characterised by hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis.

Disclosure

No significant relationships.

[The in vivo imaging of zebrafish for chemical vascular toxicity assessment]

Objective: To evaluate the vascular toxicity of chemicals by a real-time observation approach using the transgenic zebrafish. Methods: The spatiotemporal vascular alterations of transgenic zebrafish after chemical exposure were assessed by laser confocal microscopy and high-content screening analysis, respectively. Results: The method using Laser Confocal Microscopy (LCM) is easier to operate and yields high-resolution images, while it is lower throughput and inefficient. In contrast, high-content analysis (HCA) analysis obtains high-quality data of vascular toxicity manifesting whole blood vasculature, whereas it requires delicate operation procedures and advanced experimental conditions. Conclusion: Two kinds of zebrafish imaging methods each have advantages and disadvantages. LCM is suitable for the evaluation of a small number of chemicals. HCA, a cutting-edge technology, has great potential for chemical safety assessment allowing high throughput vascular toxicity tests of a good number of chemicals at a time.

Coverage and effectiveness of hypertension screening in different altitudes of Tibet autonomous region

BACKGROUND

Tibet is an autonomous region in China located around an average altitude of 4500 m above sea level. Since 2012 the local government of Tibet has been providing free physical examinations, including screening for hypertension. However, the coverage and effectiveness of this free program have not been uncovered. This study aims to assess the coverage and effectiveness of hypertension screening and management program in 3 altitude levels of Tibet, and also the determinants of the success of the screening program.

METHODS

A stratified cluster survey was conducted among 1636 residents aged 18 years or over in three different altitude areas in Tibet. We adjusted for age and sex based on national census data and used weighted logistic regression models to find factors associated with hypertension screening.

RESULTS

The coverage of the hypertension screening program evaluated by participation rate in the previous screening was 94.9%, while 24.7% (95% CI: 22.1-27.3%) of them were diagnosed with hypertension. Females and alcohol drinkers were more likely to be screened. Among those diagnosed with hypertension, 28.7% had it under control. High altitude areas had a high proportion of controlled hypertension. The overall rate of controlled hypertension in high, moderate and low altitude areas was 35.1% (95% CI: 24.8-45.3%), 32.7% (95% CI: 22.2-43.2%) and 23.7% (95% CI: 14.7-32.6%), respectively. Younger aged persons were more likely to have better control of their hypertension.

CONCLUSIONS

The coverage of hypertension screening in Tibet was high, especially in the low altitude areas. However, the effectiveness of hypertension control was low, indicating a need to implement the treatment adherence routines into the current screening interventions.

Determination of Campesterol, Stigmasterol, and Beta-Sitosterol in Saw Palmetto Raw Materials and Dietary Supplements by Gas Chromatography: Collaborative Study

An interlaboratory study was conducted to evaluate a method for the determination of campesterol, stigmasterol, and beta-sitosterol in saw palmetto raw materials and dietary supplements at levels &gt;1.00 mg/100 g based on a 23 g sample. Test samples were saponified at high temperature with ethanolic KOH solution. The unsaponifiable fraction containing phytosterols (campesterol, stigmasterol, and beta-sitosterol) was extracted with toluene. Phytosterols were derivatized to trimethylsilyl ethers and then quantified by gas chromatography with hydrogen flame ionization detection. Twelve blind duplicates, one of which was fortified, were successfully analyzed by 10 collaborators. Recoveries were obtained for the sample that was fortified. The results were 99.8, 111, and 111% for campesterol, stigmasterol, and beta-sitosterol, respectively. For repeatability, the relative standard deviation (RSDr) ranged from 3.93 to 17.3% for campesterol, 3.56 to 22.7% for stigmasterol, and 3.70 to 43.9% for beta-sitosterol. For reproducibility, the RSDR ranged from 7.97 to 22.6%, 0 to 26.7%, and 5.27 to 43.9% for campesterol, stigmasterol, and beta-sitosterol, respectively. Overall, the Study Director approved 5 materials with acceptable HorRat values for campesterol, stigmasterol, and beta-sitosterol ranging from 1.02 to 2.16.

Determination of β-Carotene in Supplements and Raw Materials by Reversed-Phase High Pressure Liquid Chromatography: Collaborative Study

Twelve laboratories representing 4 countries participated in an interlaboratory study conducted to determine all-trans-β-carotene and total β-carotene in dietary supplements and raw materials. Thirteen samples were sent as blind duplicates to the collaborators. Results obtained from 11 laboratories are reported. For products composed as softgels and tablets that were analyzed for total β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 3.35 to 23.09% and the HorRat values ranged from 1.06 to 3.72. For these products analyzed for trans β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 4.28 to 22.76% and the HorRat values ranged from 0.92 to 3.37. The RSDr and HorRat values in the analysis of a beadlet raw material were substantial and it is believed that the variability within the material itself introduced significant variation in subsampling. The method uses high pressure liquid chromatography (LC) in the reversed-phase mode with visible light absorbance for detection and quantitation. If high levels of α-carotenes are present, a second LC system is used for additional separation and quantitation of the carotene species. It is recommended that the method be adopted as an AOAC Official Method.

A Novel AMELX Mutation, Its Phenotypic Features, and Skewed X Inactivation

Amelogenesis imperfecta (AI) is a group of genetic disorders of defective dental enamel. Mutation of AMELX encoding amelogenin on the X chromosome is a major cause of AI. Here we report a Chinese family with hypoplastic and hypomineralized AI. Whole exome analysis revealed a novel mutation c.185delC in exon 5 of AMELX causing the frame shift p.Pro62ArgfsTer47 (or p.Pro62Argfs*47). By sequencing of polymerase chain reaction products and T-vector clones, the mutation was confirmed as homozygous in the proband, hemizygous in her father, and heterozygous in her mother. The proband and her father had small and yellowish teeth with thin and rough enamel that was radiographically indistinguishable from the underlying dentin. Scanning electronic microscopy of 1 maternal tooth showed cracks and exposed loosely packed enamel prisms in affected areas. Consistent with a 25:75 skewing of X inactivation in the peripheral blood DNA as measured by androgen receptor allele methylation, the surface of the mother’s tooth had alternating vertical ridges of transparent normal and white chalky enamel in a 34:66 ratio. In summary, this study provides one of the few phenotypic comparisons of hemizygous and homozygous AMELX mutations and suggests that the skewing of X inactivation in AI contributes to the phenotypic variations in heterozygous carriers of X-linked AI.

[The prevalence of allergy-related symptoms and their risk factorinvestigation in early life]

Objective:The aim of this study is to investigate the incidence of allergy-related symptoms and the associated risk factors.Method:There were 205 children aged 3 to 4 years old recruited for this study.Questionnaires on skin,wheezing and rhinitis symptoms were answered,and total IgE and specific IgE in serum against house dust mite extracts were tested.Logistic regression analysis with which we calculated odds ratio(OR) and 95% confidence interval(95%CI) were used for risk factor analysis.Result:Questionnaire results show that the reported history of symptoms was 43%(88 cases) for lactation eczema and 25%(51 cases) for wheezing.The currently reported symptoms was 19%(38 cases) for frequent skin rashes,16% (33 cases) for frequent wheezing and 46%(95 cases) for rhinitis symptoms.There are 33% (68 cases) of the children reported with no symptoms currently.The lactation eczema history(OR［95%CI］:2.76［1.10-3.40］,P<0.05)and wheezing history(OR［95%CI］:2.40［1.22-4.73］,P<0.01)are both the risk factors for developing rhinitis symptoms.Serology test shows that house dust mite IgE prevalence is 24%,which is the risk factor developing rhinitis symptom(OR［95%CI］:2.10［1.09-4.07］,P<0.05).But it has nothing to do with wheezing symptom.Conclusion:Lactation eczema and house dust mite sensitization are the risk factors for developing respiratory diseases in early childhood.The house dust mite allergic respiratory symptom starts with rhinitis symptom.

Significant Decrease in Dialysate Albumin Concentration during Molecular Adsorbent Recirculating System (M.A.R.S.) Therapy

Aim

The molecular adsorbent recirculating system (M.A.R.S.) is widely used as liver support therapy in patients with hepatic dysfunction. The goal of this study was to measure changes in dialysate albumin and bilirubin concentrations during clinical MARS treatments.

Methods

Eight patients with acute liver dysfunction and hyperbilirubinemia were enrolled in this study. Five of them received a total of 10 treatments with MARS, in which 600 mL of 20% human albumin was used as dialysate, continuously regenerated by two adsorbent columns in the circuit. Three patients received 4 treatments of a modified MARS, in which the two adsorbent columns were bypassed in the first course for 4 h, and then connected to the circuit in the second course for another 4 h. The total, conjugated and unconjugated bilirubin (TB, CB, UCB) and albumin concentrations in serum and albumin dialysate were dynamically measured, and the adsorbent column inlet pressures were recorded during each session. In one session, dialysate albumin levels were measured during the priming process, at the time points prior to the priming process, immediately after priming, and at the end of the treatment.

Results

During MARS therapies, the reduction ratio of serum TB, CB and UCB was 26.6±9.0%, 29.5±9.6% and 14.8±12.3%, respectively. The molar ratio of TB/albumin in serum was approximately 20-fold higher than dialysate at all time points. A significant albumin concentration decrease from baseline in the dialysate was found (mean±SD, 34.6±16.6%). For the first four hours of modified treatments, in which only albumin dialysis without albumin regeneration by adsorbent columns was performed, the dialysate albumin decrease was substantially smaller (mean, 8.3±1.5%). After switching to standard MARS, there was a further decrease in the dialysate albumin concentration of 35.1±14.5%. In one session, dialysate albumin concentrations were measured during the priming process, and levels decreased from 196.9 g/L to 144.4 g/L. Adsorber inlet pressure increased from 40±10mmHg at the start of priming to 150±50mmHg at the end of priming, and further increased to 340±100mmHg at the end of treatment.

Conclusion

There is a significant reduction in dialysate albumin concentration during MARS therapy. Binding of albumin to the adsorbent columns used for albumin regeneration is largely responsible for this decrease.

Improvement of Monocyte Secretion Function in a Porcine Pancreatitis Model by Continuous Dose-Dependent Veno-Venous Hemofiltration

Objective

Monocyte and its secreted cytokines play a crucial role in the process of severe acute pancreatitis (SAP). It has been known that continuous veno-venous hemofiltration (CVVH) can partially attenuate the inflammatory process by removal of cytokines, but the effect of CVVH on monocyte secretion function remains unknown. This study investigated the effect of different doses of CVVH on monocyte secretion function as well as the plasma cytokine profile in a SAP porcine model.

Methods

After successful induction of SAP by pressure-controlled (100 mmHg), intraductal injection of sodium taurocholate (4%, 1 ml/kg) and trypsin (2 U/kg), 24 swine were randomly assigned to 3 groups. Swine in group I (n=8) serving as SAP controls received only standard medical therapy (SMT). Besides SMT, swine in two other groups received zero-balanced CVVH, one hour after the induction of SAP, with low volume fluid exchange (group II, n=8, ultrafiltration rate (UFR) 20 ml/kg/h, LV-CVVH) or high volume (group III, n=8, UFR 100 ml/kg/h, HV-CVVH). Using heparin as anticoagulant, the filter (AN69, Hospal, Lyon, France) was changed every 24 hours. Monocytes were isolated from porcine blood at various timepoints for detection of cytokine secretion (interleukin-6, IL-6; interleukin-10, IL-10; tumor necrosis-α, TNF-α) after LPS stimulus; plasma cytokines were measured simultaneously.

Results

CVVH showed a dose-dependent beneficial effect on the animals’ survival time. In control animals, plasma pro-inflammatory cytokine levels exhibited a double-phase fluctuation after SAP induction: IL-6 and TNF-α rapidly increased to a peak level within 6–12 hours, then dropped to very low level in the late stage. Unlike pro-inflammatory cytokines, the plasma level of anti-inflammatory cytokine IL-10 reached a plateau within 6–12 hours but dropped little. In CVVH-treated animals, the peak-nadir patterns of 3 cytokines were all flattened, most prominently in the HV-CVVH group. Similarly to plasma cytokine patterns, the monocyte ex vivo response to LPS stimulus showed an over-production of cytokines within 6–12 hours, but low production in the late stage. Although unable to totally prevent the abnormality of the monocyte secretion function, CVVH showed a dose-dependent ameliorative effect on it.

Conclusions

Monocytes are over-reactive to stimulus in the early stage of SAP, accompanied by a high level of plasma cytokines, and hypo-reactive to stimulus in the late stage of SAP, accompanied with a low level of plasma cytokines. CVVH treatment has a dose-dependent improvement effect on monocyte responsiveness.

B4GALT family mediates the multidrug resistance of human leukemia cells by regulating the hedgehog pathway and the expression of p-glycoprotein and multidrug resistance-associated protein 1

β-1, 4-Galactosyltransferase gene (B4GALT) family consists of seven members, which encode corresponding enzymes known as type II membrane-bound glycoproteins. These enzymes catalyze the biosynthesis of different glycoconjugates and saccharide structures, and have been recognized to be involved in various diseases. In this study, we sought to determine the expressional profiles of B4GALT family in four pairs of parental and chemoresistant human leukemia cell lines and in bone marrow mononuclear cells (BMMC) of leukemia patients with multidrug resistance (MDR). The results revealed that B4GALT1 and B4GALT5 were highly expressed in four MDR cells and patients, altered levels of B4GALT1 and B4GALT5 were responsible for changed drug-resistant phenotype of HL60 and HL60/adriamycin-resistant cells. Further data showed that manipulation of these two gene expression led to increased or decreased activity of hedgehog (Hh) signaling and proportionally mutative expression of p-glycoprotein (P-gp) and MDR-associated protein 1 (MRP1) that are both known to be related to MDR. Thus, we propose that B4GALT1 and B4GALT5, two members of B4GALT gene family, are involved in the development of MDR of human leukemia cells, probably by regulating the activity of Hh signaling and the expression of P-gp and MRP1.

Genotypic resistance profile of hepatitis B virus (HBV) in a large cohort of nucleos(t)ide analogue-experienced Chinese patients with chronic HBV infection

The study investigated the hepatitis B virus (HBV) genotypic resistance profile in 1803 nucleos(t)ide analogue (NA)-experienced Chinese patients with chronic HBV infection. Serum HBV DNA was extracted, and the reverse transcriptase region was analysed by a high-sensitive direct PCR sequencing and verified by clonal sequencing if necessary. Drug-resistant mutations were detected in 560 of the 1803 patients, including 214 of 490 patients who received lamivudine (LAM), 35 of 428 patients who received adefovir (ADV), five of 18 patients who received telbivudine and 306 of 794 patients who received various sequential/combined NA therapies. ADV-resistant mutations were detected in 36 of 381 patients who received LAM and then switched-to ADV in contrast to one of 82 patients who received ADV add-on LAM. Entecavir (ETV)-resistant mutations were detected not only in LAM- and ETV-treated patients but also in LAM-treated ETV-naïve patients. Double mutations rtM204I and rtL180M were detected more frequently in genotype C than in genotype B virus, and patients infected with this mutant had higher alanine transaminase levels than those infected with mutant containing the rtM204I substitution alone. Multidrug-resistant HBV strains were identified in eight patients, including two novel strains with mutational patterns rtL180M + A181V + S202G + M204V + N236T and rtL180M + S202G + M204V + N236T. The results provide new information on HBV genotypic resistance profiles in a large cohort of Chinese patients with chronic HBV infection and may have important clinical implication for HBV drug resistance management in China.

Genistein blunts the negative effect of ischaemia to the retina caused by an elevation of intraocular pressure

AIMS

Deduce whether the isoflavone genistein blunts the effect of ischaemia to the retina.

METHODS

Ischaemia was induced in rats by raising the intraocular pressure (120 mm Hg) for 50 min. Genistein (10 mg/kg) was injected intraperitoneally 1 h before and after ischaemia. Seven days after ischaemia, the level of mRNAs for neurofilament light (NF-L), caspase 3, caspase 8, glial fibrillary acidic protein (GFAP), poly-ADP ribose polymerase (PARP), Thy-1 and proteins (GFAP, NF-L, PARP) in whole retinas were determined. NF-L and tubulin proteins in optic nerves were also determined. Retinas were also processed for the localization of choline acetyltransferase (ChAT) and GFAP immunoreactivities.

RESULTS

Ischaemia caused a significant reduction in ganglion cell proteins in the optic nerve (NF-L and tubulin) and retina (NF-L). Retinal Thy-1 (mRNA and protein) and NF-L (mRNA) were also reduced while mRNAs of caspase 3, caspase 8, PARP and GFAP (also protein) were increased. Changes in the mRNAs and proteins induced by ischaemia were significantly blunted by genistein with the exception of the increase in GFAP and PARP protein/mRNA levels. Ischaemia-induced changes in the localization of ChAT were also clearly attenuated by genistein treatment.

CONCLUSIONS

Genistein blunts most of the damaging effects caused to the retina by ischaemia.

The flavonoid baicalin counteracts ischemic and oxidative insults to retinal cells and lipid peroxidation to brain membranes

The purpose of the present study was to determine whether the flavonoid, baicalin is effective at blunting the negative influence of ischemia/reperfusion to the rat retina in situ and of various insults to a transformed retinal ganglion cells (RGC-5 cells) in culture. Baicalin was administered intraperitoneally just before and after an ischemic insult to retina of one eye of a rat. Ischemia was delivered by raising the intraocular pressure above the systolic blood pressure for 50min. Seven days after ischemia, retinas were analysed for the localisation of various antigens. Retinal extracts were also analysed for various mRNAs. Moreover, the content of specific proteins was deduced in retinal and optic nerve extracts. Also, RGC-5 cells in culture were given one of three different insults, light (1000lx for 2 days), hydrogen peroxide (200microM H(2)O(2) for 24h) or serum deprivation (48h) where cell survival and reactive oxygen species (ROS) formation was assayed. Moreover, a lipid peroxidation assay was used to compare the antioxidant capacity of baicalin with the flavonoid, epigallocatechin gallate (EGCG). Ischemia/reperfusion to the retina affected the localisation of Thy-1 and choline acetyltransferase (ChAT) and the content of various proteins (optic nerve and retina) and mRNAs (retina). Importantly, baicalin statistically blunted most of the effects induced by ischemia/reperfusion. Only the increase in caspase-8 and caspase-3 mRNAs caused by ischemia/reperfusion were unaffected by baicalin treatment. Baicalin also attenuated significantly the negative insult of light, hydrogen peroxide and serum withdrawal to RGC-5 cells. In the lipid peroxidation studies, baicalin was also found to be equally effective as EGCG to act as an antioxidant. Significantly, the negative insult of serum withdrawal on RGC-5 cell survival was blunted by baicalin but not by EGCG revealing the different properties of the two flavonoids.

Selective albumin exchange: a novel and simple method to remove bilirubin

PURPOSE

Owing to its non-selectivity, plasma exchange has limited use in the treatment of patients with hepatic failure, although it is effective in removal of protein-bound toxins. This study reports a novel way to perform selective albumin exchange (SAE) by using a secondary plasma separator and aims to study its depurative capacity in the removal of bilirubin.

METHOD

In ex vivo experiments, the sieving coefficients (SCs) of plasma proteins for two secondary plasma separators, EC20W and EC30W (Asahi Medical, Tokyo, Japan), were measured. The EC20W membrane was chosen for use in clinical treatment because of its higher selectivity in separating albumin from plasma than the EC30W. The SCs of albumin, immunoglobumin G, A and M (IgG, IgA, IgM) for the EC20W were 0.3+/-0.021, 0.017+/-0.012, and 0, respectively. Five inpatients with plasma total bilirubin (TB) more than 200 micromol/L were enrolled in the present study and received a total of 10 SAE therapy sessions. Each session lasted 10 hours. SAE using the EC20W was conducted, making it similar to post-dilution continuous veno-venous hemofiltration (CVVH), with a filtrate rate of 2000 ml/h. Replacement fluid was composed by adding human albumin into conventional CVVH replacement fluid, with a final albumin concentration of 0.6%. During each treatment, the parameters of plasma and filtrate TB, direct bilirubin (DB), indirect bilirubin (IDB), and proteins were dynamically monitored. Hemostasis parameters were measured before and after sessions.

RESULTS

The reduction ratio of plasma TB, DB, and IDB after a single session was 29.1+/-3.0%, 31.3+/-4.5%, and 18.7+/-10.2%, respectively. The clearance of TB at initiation was 11.1+/-1.3 mL/min and declined to 4.4+/-0.5 ml/min at the end (p<0.01). This decline was accompanied by a reduction in albumin SC from 0.3+/-0.021 to 0.13+/-0.05. The molar ratio of bilirubin to albumin in filtrate was comparable to that in plasma. After a single treatment, plasma protein concentration including total protein, albumin, IgA and IgM remained unaffected, except for globulin and IgG, which were reduced by 11.5+/-7.8% and 11.1+/-2.3%, respectively. An improvement in hemostasis parameters, including plasma fibrinogen, prothrombase time and INR, was found after treatment. No obvious side effects were reported during any of the sessions.

CONCLUSION

Selective albumin exchange is a simple and effective method to remove bilirubin. However, further studies are required to verify its effects on clinical outcome.

[Cloning of genes transactivated by nonstructural protein 4A of hepatitis C virus.]

BACKGROUND

To construct a subtractive cDNA library of genes transactivated by NS4A protein of hepatitis C virus with suppression subtractive hybridization technique (SSH).

METHODS

The mRNA was isolated from Hep G2 cells transfected pcDNA3.1(-)-NS4A and pcDNA3.1(-) empty vector, respectively, then the cDNA was synthesized. SSH method was employed to analyze the differentially expressed RNA sequence between the two groups. The twice enriched PCR products were subcloned into T/A vectors to set up the subtractive library. Amplification of the library was carried out with E.coli strain JM109. The cDNA was sequenced and analyzed in comparison with those in GenBank with Blast search after PCR.

RESULTS

The amplified library contained 36 positive clones. Colony PCR showed that 36 clones contained 200-1000 bp inserts. Sequence analysis was performed in 25 clones, and the full length sequences were obtained with bioinformatics method. Altogether 20 kinds of coding sequences were achieved, which consisted of 18 kinds of known and 2 kinds of unknown ones. The obtained sequences may be target genes transactivated by NS4A protein of HCV, among which some genes coding for proteins involved in cell cycle regulation, cell apoptosis, signal transduction pathway and tumour development.

CONCLUSION

A subtractive library of genes transactivated by NS4A protein of HCV was constructed successfully, which brought some new clues for studying the biological functions and pathogenesis of the viral proteins.

Downregulation of cAMP-dependent protein kinase inhibitor gamma is required for BMP-2-induced osteoblastic differentiation

Osteoblasts, normally derived from undifferentiated mesenchymal precursor cells, acquire their characteristic phenotypes when induced by various regulatory factors, one of which is bone morphogenetic protein-2 (BMP-2). Our recent studies suggest that expression of cAMP-dependent protein kinase (PKA) inhibitor G (PKIG) is down-regulated as human mesenchymal stromal cells (MSCs) undergo BMP-2-induced osteoblastic differentiation. This raises our hypothesis that the PKA pathway is involved in osteogenesis. In this report, we demonstrated that PKIG in human MSCs and its murine homologue PKA inhibitor gamma (PKIgamma) in murine pre-myoblast C2C12 cells were down-regulated when these cells were treated with BMP-2. On the contrary, the PKA activity of C2C12 cells was increased upon BMP-2 treatment. Overexpression of PKIgamma in C2C12 cells was shown to repress mRNA expression of early osteoblastic markers osterix and type I collagen while inhibiting the PKA activity. This correlated with decreased alkaline phosphatase (ALP) activities. Furthermore, inhibition of the PKA activity using its specific inhibitor KT5720 was found to have the similar effect, whereas 8-Br-cAMP, a specific PKA activator, accelerated BMP-2-induced ALP activities. Finally, this study showed that BMP-2 treatment promoted activities of transcription regulatory elements including cAMP response element (CRE) and activating protein-1 (AP1). This effect of BMP-2 was diminished in PKIgamma-overexpressed C2C12 cells. Taken together, our results indicate that the activation of the PKA pathway may be one of key BMP-2-activated signaling events that lead to osteogenesis and that downregulation of PKIgamma may be prerequisite for the PKA activation during the osteoblastic differentiation of precursor cells.

Decomposition of 2-naphthalenesulfonate in aqueous solution by ozonation with UV radiation

This study investigates the ozonation of 2-naphthalenesulfonate (2-NS) combined with ultraviolet (UV) radiation. Naphthalenesulfonic acids are of importance as dye intermediates for the dye and textile auxiliary industries. Its derivatives, such as 2-NS, have been found in rivers and tannery effluents causing pollution problems. Thus, the 2-NS is of concern for the aquatic pollution control especially in the surface and waste waters. Ozonation combined with UV radiation is employed for the removal of 2-NS in the aqueous solution. Semibatch ozonation experiments were proceeded under different reaction conditions to study the effects of ozone dosage and UV radiation on the oxidation of 2-NS. The concentrations of 2-NS and sulfate are analyzed at specified time intervals to elucidate the decomposition of 2-NS. In addition, values of pH and oxidation reduction potential are continuously measured in the course of experiments. Total organic carbon is chosen as a mineralization index of the ozonation of 2-NS. The mineralization of 2-NS via the ozonation is remarkably enhanced by the UV radiation. These results can provide useful information for the proper removal of 2-NS in the aqueous solution by the ozonation with UV radiation.

A retrospective study of continuous renal replacement therapy versus intermittent hemodialysis in severe acute renal failure

OBJECTIVE

To investigate the efficacy of continuous renal replacement therapy (CRRT) versus intermittent hemodialysis (IHD) in patients with severe acute renal failure (ARF).

METHODS

One hundred and ninety-three severe ARF patients who received renal support between December 1978 and December 1998 were involved in this study. Of them, 101 (52.3%) were treated with CRRT (CRRT group), and 92 (47.7%) with IHD (IHD group).

RESULTS

Sixty (59.4%) patients in the CRRT group got through the acute phase of disease and 41 (40.6%) patients did not survive while in the IHD group 59 (64.1%) patients survived and 33 (35.9%) patients did not. No significant difference in survival rate was found between the two groups. 24 of 64 patients (37.5%) in the CRRT group with multiple organ dysfunction syndrome (MODS) survived, while in the IHD group, 8 out of 44 (27.3%) survived, their survival rate was much lower than that in the CRRT group. Patients in CRRT group were more severely ill, as manifested by lower mean arterial pressure, higher APACHE II score, more dysfunctioned organs and requiring mechanical ventilation and vasopressor support as compared with patients in the IHD group, CRRT was found to improve hemodynamic stability with a better fluid balance and control of biochemical status, increased nutritional intake and a shorter duration of acute renal failure (P < 0.05).

CONCLUSION

CRRT perhaps may be the best choice in the treatment of severe ARF patients, for it can offer several distinct advantages compared to IHD. These may contribute to improving the survival rate of ARF patients, particularly those that are critically ill patients.

Synaptic plasticity and nicotine addiction

Nicotine, the main addictive component of tobacco, activates and desensitizes nicotinic acetylcholine receptors (nAChRs). In that way, nicotine alters normal nicotinic cholinergic functions. Among the myriad of psychopharmacological effects that underlie the addiction process, nicotine influences nAChR participation in synaptic plasticity. This influence has particular importance in the mesocorticolimbic dopamine system, which serves during the reinforcement of rewarding behaviors.

Timing and location of nicotinic activity enhances or depresses hippocampal synaptic plasticity

This study reveals mechanisms in the mouse hippocampus that may underlie nicotinic influences on attention, memory, and cognition. Induction of synaptic plasticity, arising via generally accepted mechanisms, is modulated by nicotinic acetylcholine receptors. Properly timed nicotinic activity at pyramidal neurons boosted the induction of long-term potentiation via presynaptic and postsynaptic pathways. On the other hand, nicotinic activity on interneurons inhibited nearby pyramidal neurons and thereby prevented or diminished the induction of synaptic potentiation. The synaptic modulation was dependent on the location and timing of the nicotinic activity. Loss of these synaptic mechanisms may contribute to the cognitive deficits experienced during Alzheimer's diseases, which is associated with a loss of cholinergic projections and with a decrease in the number of nicotinic receptors.

[The effects of dialysate and ultrafiltration flow rate on solute clearance during continuous renal replacement therapy]

OBJECTIVE

To study the solute clearance during various forms of continuous renal replacement therapy(CRRT) and test the formulas that allow the prediction of the influence of dialysate and ultrafiltration flow rate on small solute removal during CRRT.

METHOD

Five patients with acute renal failure were included in the study and were treated by venovenous CRRT using the PRISMA predilution system. Solute clearance of urea nitrogen(UN), creatinine(Cr), uric acid(Ua), phosphate(P) and beta(2)-microglobulin(beta(2)-M) were evaluated during CRRT with different dialysates and ultrafiltration flow rates.

RESULTS

The determined clearance of small molecular solutes during continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodialysis(CVVHD) was similar with the following formulas: K(UF) = (Q(UF)/60) x Q(B)/(Q(B) + Q(UF)/60) (in CVVH), Kd = Q(D)/60 (in CVVHD), where K is the clearance, Q(B), Q(D) and Q(UF) are blood, dialysate and ultrafiltration flow rates, respectively. There was very significant correlation between calculated values of K(UF) and observed clearances of small solutes such as UN, Cr, Ua and P during CVVH, between calculated values of Kd and observed clearances of UN, Cr, Ua but not P during CVVHD (P < 0.001). Clearances of UN, Cr, Ua and P during CVVHD were greater than those during CVVH, but clearance of beta(2)-M during CVVHD was less than that during CVVH. Interaction between convection and diffusion was found during continuous venovenous hemodiafiltration (CVVHDF).

CONCLUSIONS

The previous formulas can provide with the prediction of the clearance of small molecular solutes during CVVH and CVVHD. The present results demonstrate that diffusion is more efficient in removing small solutes than convection but less efficient in removing large solutes than convection. There is interaction between convection and diffusion during CVVHDF.

Interaction of oxo-bridged vanadium(III) phenanthroline and bipyridine dimers with DNA

Cationic mu-oxo V(III) dimers of the type [V2OL4Cl2]2+ (L = 1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline; or 2,2'-bipyridine) are shown to interact very strongly with DNA and to lead ultimately to its degradation. Spectroscopic binding studies, electrophoreses, DNA melting temperature experiments, and other tests on the parent 1,10-phenthroline complex all yield results consistent with tight binding. However, the exact nature of the binding--i.e., intercalative, groove binding, electrostatic, or covalent--remains unclear. Resonance Raman spectroscopy is found to be a powerful method for studying the interaction of these mu-oxo V(III) dimers with DNA and shows that in frozen aqueous solution, the parent complex [V2O(phen)4Cl2]2+ undergoes initial aquation, followed by the reaction of the aquated species with the DNA. Once the V(III) dimer is bound to the DNA, redox takes place, leading to the formation of alkaline-sensitive lesions. Hydrogen peroxide is implicated as a partner in this redox event, based on the effects of the enzymes SOD and catalase.

Inhibition and disinhibition of pyramidal neurons by activation of nicotinic receptors on hippocampal interneurons

Nicotinic acetylcholine receptors (nAChRs) are expressed in the hippocampus, and their functional roles are beginning to be delineated. The effect of nAChR activation on the activity of both interneurons and pyramidal neurons in the CA1 region was studied in rat hippocampal slices. In CA1 stratum radiatum with muscarinic receptors inhibited, local pressure application of acetylcholine (ACh) elicited a nicotinic current in 82% of the neurons. The majority of the ACh-induced currents were sensitive to methyllycaconitine, which is a specific inhibitor of alpha7-containing nAChRs. Methyllycaconitine-insensitive nicotinic currents also were present as detected by a nonspecific nAChR inhibitor. The ACh-sensitive neurons in the s. radiatum were identified as GABAergic interneurons by their electrophysiological properties. Pressure application of ACh induced firing of action potentials in approximately 70% of the interneurons. The ACh-induced excitation of interneurons could induce either inhibition or disinhibition of pyramidal neurons. The inhibition was recorded from the pyramidal neuron as a burst of GABAergic synaptic activity. That synaptic activity was sensitive to bicuculline, indicating that GABA(A) receptors mediated the ACh-induced synaptic currents. The disinhibition was recorded from the pyramidal neuron as a reduction of spontaneous GABAergic synaptic activity when ACh was delivered onto an interneuron. Both the inhibition and disinhibition were sensitive to either methyllycaconitine or mecamylamine, indicating that activation of nicotinic receptors on interneurons was necessary for the effects. These results show that nAChRs are capable of regulating hippocampal circuits by exciting interneurons and, subsequently, inhibiting or disinhibiting pyramidal neurons.

Suppression of morphine withdrawal by electroacupuncture in rats: dynorphin and kappa-opioid receptor implicated

Our previous work has demonstrated that 100-Hz electroacupuncture (EA) or 100-Hz transcutaneous electrical nerve stimulation (TENS) was very effective in ameliorating the morphine withdrawal syndrome in rats and humans. The mechanism was obscure. (1) Rats were made dependent on morphine by repeated morphine injections (5-140 mg/kg, s.c., twice a day) for eight days. They were then given 100-Hz EA for 30 min 24 h after the last injection of morphine. A marked increase in tail flick latency (TFL) was observed. This effect of 100-Hz EA could be blocked by naloxone (NX) at 20 mg/kg, but not at 1 mg/kg, suggesting that 100-Hz EA-induced analgesia observed in morphine-dependent rats is mediated by kappa-opioid receptors. (2) A significant decrease of the concentration of dynorphin A (1-17) immunoreactivity (-ir) was observed in the spinal perfusate in morphine-dependent rats, that could be brought back to normal level by 100-Hz EA. (3) 100-Hz EA was very effective in suppressing NX-precipitated morphine withdrawal syndrome. This effect of EA could be prevented by intrathecal administration of nor-BNI (2.5 micrograms/20 microliters), a kappa-opioid receptor antagonist, or dynorphin A (1-13) antibodies (25 micrograms/20 microliters) administered 10 min prior to EA. In conclusion, while the steady-state spinal dynorphin release is low in morphine-dependent rats, it can be activated by 100-Hz EA stimulation, which may be responsible for eliciting an analgesic effect and ameliorating morphine withdrawal syndrome, most probably via interacting with kappa-opioid receptor at spinal level.

[Treatment of severe acute renal failure with continuous renal replacement therapy]

OBJECTIVE

To present the experience in 101 severe acute renal failure (ARF) patients treated with continuous renal replacement therapy (CRRT) in our hospital from May 1986 to January 1999.

METHODS

Patients'age, sex, previous health status and characteristics of renal failure were recorded. The acute physiology and chronic health evaluation II (APACHE II) score were calculated before CRRT treatment.

RESULTS

60 (59.4%) patients survived the acute phase of their illness, and 41 (40.6%) patients died. In the survival group, there were significantly less patients with pre-renal causes of renal failure and refractory course of uremia, low APACHE II score before treatment and less need of mechanical ventilation or vasoactive supporting. No difference was found in the percentage of oliguria between the survival and total group.

CONCLUSION

CRRT is the treatment of first choice in ARF, especially in those complicated cases with severe parachymal renal diseases. The patients' age, previous health status, APACHE II score before CRRT, delayed occurrence of acute renal failure, need of mechanical ventilation and vasoactive drugs were predictors of a worse prognosis in severe ARF patient. The prognosis of renal type ARF patients improved with CRRT.

Effect of chitosan on renal function in patients with chronic renal failure

The effects of chitosan have been investigated on eighty patients with renal failure undergoing long-term stable haemodialysis treatment. The patients were tested after a control treatment period of 1 week. Half were fed 30 chitosan tablets (45 mg chitosan/tablet) three times a day. Ingestion of chitosan effectively reduced total serum cholesterol levels (from 10.14 +/- 4.40 to 5.82 +/- 2.19 mM) and increased serum haemoglobin levels (from 58.2 +/- 12.1 to 68 +/- 9.0 g L-1). Significant reductions in urea and creatinine levels in serum were observed after 4 weeks of chitosan ingestion. The feeling of physical strength, the appetite and the sleep of patients in the treatment group had improved significantly after 12 weeks of ingestion, compared with those of patients in the control group. During the treatment period, no clinically problematic symptoms were observed. These data suggest that chitosan might be effective treatment for renal failure patients, although the mechanism of the effect should be investigated further.