Diversity of left-right symmetry breaking strategy in animals

Left-right (L-R) asymmetry of visceral organs in animals is established during embryonic development via a stepwise process. While some steps are conserved, different strategies are employed among animals for initiating the breaking of body symmetry. In zebrafish (teleost), Xenopus (amphibian), and mice (mammal), symmetry breaking is elicited by directional fluid flow at the L-R organizer, which is generated by motile cilia and sensed by mechanoresponsive cells. In contrast, birds and reptiles do not rely on the cilia-driven fluid flow. Invertebrates such as Drosophila and snails employ another distinct mechanism, where the symmetry breaking process is underpinned by cellular chirality acquired downstream of the molecular interaction of myosin and actin. Here, we highlight the convergent entry point of actomyosin interaction and planar cell polarity to the diverse L-R symmetry breaking mechanisms among animals.

A59 A strategy to studying zoonotic infectious diseases

An increasing number of zoonotic viruses have been detected in animals, especially in poultry species. Understanding the diversity of zoonotic infections and the local behavior helps to characterize the pathogen diversity in human and animals and predict the risk of pathogen spill-over from animals to human. Vietnam is considered, along with other countries in Southeast Asia, as a hotspot for zoonotic viruses. In Vietnam, domestic animals are typically farmed in close proximity to humans, which may increase the risk of transmission of zoonotic pathogens. Our previous studies found the presence of some zoonotic viruses (e.g. rotavirus group A, hepatitis E virus) in domestic pigs. However, the risk of pathogenic transmission from domestic animals to humans has not been determined. Detailed genomic sequence data may help to track the origin and evolution of zoonotic pathogens. To understand the origins and emergence of zoonotic infections in people, who have regular contact with animals, we will investigate the viral diversity in farmers and domestic animals in their farm, using high-throughput sequencing technique. Viral RNA was extracted from pooled fecal samples of 30 farmers and 50 pigs, and used as input for SureSelect target enrichment and Illumina MiSeq sequencing.

The Toronto Western Hospital Catheter: One Center's Experience and Review of the Literature

Background

We report our center's experience with the Toronto Western Hospital (TWH) catheter, and discuss our catheter survival and complication rates.

Methods

Retrospective chart review of patients receiving peritoneal dialysis therapy via a TWH catheter. Catheter complication rates of peritonitis, exit site infection, obstruction, leak, and malfunction were assessed. A catheter was considered failed if removed because of exit site infection, obstruction, or malfunction. All other catheters, even if removed for other reasons, were considered censured. Survival was defined as the period from insertion to failure or censure date, and reported using Kaplan Meier analysis.

Results

192 patients with a total of 208 TWH catheters (4,845.3 catheter months) were analyzed. Our overall 1- and 3-year catheter survival rates were identical at 0.9182. Our catheter complication rates (expressed as number of catheter months per event) were 31.3 for peritonitis, 42.9 for exit site infection, 72.3 for obstruction, 538.4 for malfunction, and 969.1 for catheter leak. Our findings were similar to those reported in the literature for TWH and other peritoneal catheters.

Is congenital pulmonary airway malformation really a rare disease? Result of a prospective registry with universal antenatal screening program

BACKGROUND

Congenital pulmonary airway malformation (CPAM) is an increasingly recognized disease with potential mortality. Owing to limited published studies, the true incidence is yet to be determined. We carried out this prospective study with the aim to estimate its true incidence on a population basis.

METHODS

An antenatal ultrasonography program was implemented since 2009. Fetuses with suspected intra-thoracic lesions were monitored by regular follow-ups. Antenatal course, postnatal outcomes, and other demographics were compared to those of patients with CPAM in the previous decades (1989-2008). The incidence of CPAM was calculated in different periods.

RESULTS

66 CPAM patients were identified between 2009 and 2014 with 62 patients being detected by antenatal scan. In contrast, 45 patients were identified between 1989 and 2008 with 27 patients being detected antenatally. The incidence rate during the past and recent period was estimated as ~1 in 27,400 and ~1 in 7200 live births, respectively (p = 0.024).

CONCLUSION

With increasing awareness of clinicians and the universal use of latest ultrasound technology, it is likely that more CPAM cases will be detected in the future. Here, we presented our best estimated incidence rate of CPAM, yet only a larger scale study can reveal its true incidence.

Silver containing hydrofiber dressing promotes wound healing in paediatric patients with partial thickness burns

INTRODUCTION

Burn injury is one of the most common reasons for admission in paediatric population. There is currently no international consensus on the best wound dressing material. Aquacel Ag, a new silver containing hydrofiber dressing material has been reported to produce good clinical results. Yet, only a limited number of studies exist in the paediatric population. This study aims to review our experience of burn management over the past 5 years and to evaluate the effectiveness of Aquacel Ag in the management of partial thickness burns.

METHODS

A retrospective review of all patients admitted for burn injury between January 2010 and December 2014 was conducted. Patients' demographics, mechanism of injury, body surface areas involved, treatment applied, and clinical outcomes were analyzed. Patients with superficial injury, full thickness burns that required surgical debridement, burn area less than 2 % or more than 25 % of total body surface area, or incomplete clinical data were excluded from the comparative study.

RESULTS

A total of 119 patients were identified. 114 (96 %) was due to domestic injury, of which 108 (91 %) was food-related. The most commonly affected areas were limbs (n = 89, 74.8 %), followed by trunk (n = 62, 74.8). 84 patients fulfilled the inclusion criteria and were recruited into the study. 31 patients received Aquacel Ag dressing and 53 patients received standard paraffin gauze dressing. The two groups showed no statistical difference in age, sex, percentage of total body surface area involved, and infection rate. Outcomes of patients treated with Aquacel Ag were compared with patients treated with standard dressing. The mean hospital stay was significantly shorter for the Aquacel Ag group (14.26 vs 23.45, p = 0.045). Aquacel Ag group required much less frequent dressing change (5.67 vs 20.59, p = 0.002). 5 patients in standard dressing group developed hypertrophic scar and required prolonged pressure garment, whereas only one hypertrophic scar was observed in the Aquacel Ag group.

CONCLUSION

Aquacel Ag appears to promote early burn wound healing with less hypertrophic scar formation.

The feasibility and efficacy of multi-channel intraluminal impedance monitoring in children

INTRODUCTION

The diagnosis of gastro-oesophageal reflux is currently based on clinical presentation and oesophageal pH monitoring. In recent years, the use of multi-channel intraluminal impedance (MII) monitoring has gained increasing attention in the adult population. However, its use in the paediatric population is still in the developing stage with only limited number of publications. This study aims to review our early experience of MII application in children.

METHODS

A retrospective study of all patients who underwent MII monitoring between 2011 and 2014 at a tertiary referral centre was performed. Patients' medical records were reviewed with demographic data extracted. Number of reflux episodes and other MII parameters were analysed.

RESULTS

In total, 34 patients were identified during the study period, with 20 males and 14 females. Indication for study included previous aspiration pneumonia (n = 13), persistent reflux or vomiting symptom (n = 10) and as part of routine assessment before gastrostomy (n = 11). At the time of study the average age was 69 months (range 9-216 months). 28 patients showed significant gastro-oesophageal reflux. On average patient has 36.1 acidic and 22.3 non-acidic reflux episodes during the 24 h monitoring period. Non-acidic reflux accounts for 38.1 % of the overall reflux episodes. The sensitivity of MII monitoring to detect reflux was higher compared to conventional pH study (73 vs 50 %, p = 0.1).

CONCLUSION

MII monitoring is safe and feasible in children. Non-acid reflux should not be underestimated in paediatric population. MII appears to be more sensitive than conventional pH monitoring in our study, but its true significance is yet to be confirmed by larger study in the future.

The effects of the novel SHIP1 activator AQX-1125 on allergen-induced responses in mild-to-moderate asthma

BACKGROUND

SH2-containing inositol-5'-phosphatase 1 (SHIP1) is an endogenous inhibitor of the phosphoinositide-3-kinase pathway that is involved in the activation and chemotaxis of inflammatory cells. AQX-1125 is a first-in-class, oral SHIP1 activator with a novel anti-inflammatory mode of action.

OBJECTIVE

To evaluate the effects of AQX-1125 on airway responses to allergen challenge in mild-to-moderate asthmatic patients.

METHODS

A randomized, double-blind, placebo-controlled, two-way crossover study was performed in 22 steroid-naïve mild-to-moderate asthmatics with a documented late-phase response to inhaled allergen (LAR). AQX-1125 (450 mg daily) or placebo was administered orally for 7 days. Allergen challenge was performed on day 6 (2 h postdose), followed by methacholine challenge (day 7), and induced sputum collection and fractional exhaled nitric oxide (FeNO).

RESULTS

AQX-1125 significantly attenuated the late-phase response compared with placebo (FEV1 4-10 h: mean difference 150 mL, 20%; P = 0.027) and significantly increased the minimum FEV1 during LAR (mean difference 180 mL; P = 0.014). AQX-1125 had no effect on the early-phase response. AQX-1125 showed a trend in reduction of sputum eosinophils, neutrophils and macrophages although this did not achieve significance as there were only 11 paired samples for analysis. There was no effect on methacholine responsiveness or FeNO. Pharmacokinetic data showed AQX-1125 was rapidly absorbed with geometric mean Cmax and AUC0-24 h values of 1417 ng/mL and 16 727 h ng/mL, respectively. AQX-1125 was well tolerated, but mild GI side-effects (dyspepsia, nausea and abdominal pain) were described in 4/22 subjects on active treatment. These side-effects were mild self-limiting, required no further treatment and did not lead to discontinuation of therapy.

CONCLUSION AND CLINICAL RELEVANCE

AQX-1125, a novel oral SHIP1 activator, significantly reduces the late response to allergen challenge, with a trend to reduce airway inflammation. AQX-1125 was safe and well tolerated and merits further investigation in inflammatory disorders.

Integration of metabolic and inflammatory mediator profiles as a potential prognostic approach for septic shock in the intensive care unit

INTRODUCTION

Septic shock is a major life-threatening condition in critically ill patients and it is well known that early recognition of septic shock and expedient initiation of appropriate treatment improves patient outcome. Unfortunately, to date no single compound has shown sufficient sensitivity and specificity to be used as a routine biomarker for early diagnosis and prognosis of septic shock in the intensive care unit (ICU). Therefore, the identification of new diagnostic tools remains a priority for increasing the survival rate of ICU patients. In this study, we have evaluated whether a combined nuclear magnetic resonance spectroscopy-based metabolomics and a multiplex cytokine/chemokine profiling approach could be used for diagnosis and prognostic evaluation of septic shock patients in the ICU.

METHODS

Serum and plasma samples were collected from septic shock patients and ICU controls (ICU patients with the systemic inflammatory response syndrome but not suspected of having an infection). (1)H Nuclear magnetic resonance spectra were analyzed and quantified using the targeted profiling methodology. The analysis of the inflammatory mediators was performed using human cytokine and chemokine assay kits.

RESULTS

By using multivariate statistical analysis we were able to distinguish patient groups and detect specific metabolic and cytokine/chemokine patterns associated with septic shock and its mortality. These metabolites and cytokines/chemokines represent candidate biomarkers of the human response to septic shock and have the potential to improve early diagnosis and prognosis of septic shock.

CONCLUSIONS

Our findings show that integration of quantitative metabolic and inflammatory mediator data can be utilized for the diagnosis and prognosis of septic shock in the ICU.

Characterization of AQX-1125, a small-molecule SHIP1 activator: Part 1. Effects on inflammatory cell activation and chemotaxis in vitro and pharmacokinetic characterization in vivo

BACKGROUND

The SH2-containing inositol-5'-phosphatase 1 (SHIP1) metabolizes PI(3,4,5)P3 to PI(3,4)P2. SHIP1-deficient mice exhibit progressive inflammation. Pharmacological activation of SHIP1 is emerging as a potential therapy for pulmonary inflammatory diseases. Here we characterize the efficacy of AQX-1125, a small-molecule SHIP1 activator currently in clinical development.

EXPERIMENTAL APPROACH

The effects of AQX-1125 were tested in several in vitro assays: on enzyme catalytic activity utilizing recombinant human SHIP1, on Akt phosphorylation in SHIP1-proficient and SHIP1-deficient cell lines, on cytokine release in murine splenocytes, on human leukocyte chemotaxis using modified Boyden chambers and on β-hexosaminidase release from murine mast cells. In addition, pharmacokinetic and drug distribution studies were performed in rats and dogs.

RESULTS

AQX-1125 increased the catalytic activity of human recombinant SHIP1, an effect, which was absent after deletion of the C2 region. AQX-1125 inhibited Akt phosphorylation in SHIP1-proficient but not in SHIP1-deficient cells, reduced cytokine production in splenocytes, inhibited the activation of mast cells and inhibited human leukocyte chemotaxis. In vivo, AQX-1125 exhibited >80% oral bioavailability and >5 h terminal half-life.

CONCLUSIONS

Consistent with the role of SHIP1 in cell activation and chemotaxis, the SHIP1 activator AQX-1125 inhibits Akt phosphorylation, inflammatory mediator production and leukocyte chemotaxis in vitro. The in vitro effects and the pharmacokinetic properties of the compound make it a suitable candidate for in vivo testing in various models of inflammation.

Characterization of AQX-1125, a small-molecule SHIP1 activator: Part 2. Efficacy studies in allergic and pulmonary inflammation models in vivo

BACKGROUND

The efficacy of AQX-1125, a small-molecule SH2-containing inositol-5'-phosphatase 1 (SHIP1) activator and clinical development candidate, is investigated in rodent models of inflammation.

EXPERIMENTAL APPROACH

AQX-1125 was administered orally in a mouse model of passive cutaneous anaphylaxis (PCA) and a number of rodent models of respiratory inflammation including: cigarette smoke, LPS and ovalbumin (OVA)-mediated airway inflammation. SHIP1 dependency of the AQX-1125 mechanism of action was investigated by comparing the efficacy in wild-type and SHIP1-deficient mice subjected to an intrapulmonary LPS challenge.

RESULTS

AQX-1125 exerted anti-inflammatory effects in all of the models studied. AQX-1125 decreased the PCA response at all doses tested. Using bronchoalveolar lavage (BAL) cell counts as an end point, oral or aerosolized AQX-1125 dose dependently decreased the LPS-mediated pulmonary neutrophilic infiltration at 3-30 mg kg⁻¹ and 0.15-15 μg kg⁻¹ respectively. AQX-1125 suppressed the OVA-mediated airway inflammation at 0.1-10 mg kg⁻¹. In the smoke-induced airway inflammation model, AQX-1125 was tested at 30 mg kg⁻¹ and significantly reduced the neutrophil infiltration of the BAL fluid. AQX-1125 (10 mg kg⁻¹) decreased LPS-induced pulmonary neutrophilia in wild-type mice but not in SHIP1-deficient mice.

CONCLUSIONS

The SHIP1 activator, AQX-1125, suppresses leukocyte accumulation and inflammatory mediator release in rodent models of pulmonary inflammation and allergy. As shown in the mouse model of LPS-induced lung inflammation, the efficacy of the compound is dependent on the presence of SHIP1. Pharmacological SHIP1 activation may have clinical potential for the treatment of pulmonary inflammatory diseases.

Role of polymorphisms of the inflammatory response genes and DC-SIGNR in genetic susceptibility to SARS and other infections

1. A genetic risk-association study involving more than 1200 subjects showed individuals homozygous for L-SIGN tandem repeats are less susceptible to SARS infection. 2. This was supported by in vitro binding studies that demonstrated homozygous L-SIGN, compared to heterozygous, had higher binding capacity for SARS coronavirus (SARS-CoV), with higher proteasome-dependent viral degradation. In contrast, homozygous L-SIGN demonstrated lower binding capacity for HIV1-gp120.3. Genetic-association studies for single nucleotide polymorphisms of the inflammatory response genes, namely TNF-alpha, INF-alpha, INF-beta, INF-gamma, IL1-alpha, IL1-beta, IL-4, IL-6 and iNOS, failed to show a significant association with SARS clinical outcomes or susceptibility.

Efficacy and safety of disodium ascorbyl phytostanol phosphates in men with moderate dyslipidemia

OBJECTIVE

This study investigated the efficacy, safety, tolerability, and pharmacokinetics of a novel cholesterol absorption inhibitor, FM-VP4, comprising disodium ascorbyl sitostanol phosphate (DASP) and disodium ascorbyl campestanol phosphate (DACP).

METHODS

In phase 1, 30 men received a single dose of 100, 200, 400, 800, 1,600, or 2,000 mg FM-VP4 or placebo. In phase 2, 100 men were treated with 100, 200, 400, or 800 mg/day of FM-VP4 or placebo for 4 weeks.

RESULTS

The drug was well tolerated at each single or multiple dose level. After 4 weeks of treatment, low-density lipoprotein cholesterol (LDL-C) levels changed by 2.7% in the placebo group and by 2.9%, -4.2%, and -4.6% in the 100, 200, and 800 mg/day groups, respectively, which was not statistically significant. However, 400 mg/day of FM-VP4 significantly decreased LDL-C by 6.5% (p=0.02). Phase 1 showed that DACP and DASP were absorbed into plasma with a median t(max) of 12 h for both components, and clearance was slow with a mean t(1/2lambda) of 57 h. During 4 weeks of treatment, steady state was reached by approximately 8 days.

CONCLUSION

This study demonstrated that up to 800 mg/day of FM-VP4 is safe and well tolerated for at least 4 weeks. Furthermore, the higher doses significantly reduced LDL-C by 7% compared with baseline or by 10% compared with placebo, with the maximum effect reached at 400 mg/day.

A hepaticojejunostomy: technical errors with 'twists and turns'

Excision of a choledochal cyst followed by biliary reconstruction with a Roux-en-Y hepaticojejunostomy is the treatment of choice for type I and IV choledochal cysts. We present a rare complication which was identified 8 years after the original reconstructive surgery. Conventional imaging modalities failed to identify the pathology. Only a contrast enhanced CT scan supported by image rendering software allowed for the visualization of the underlying chronic obstruction of part of the mesentery.

Severe vitamin D deficiency in chronic renal failure patients on peritoneal dialysis

The aim of this study was to evaluate the prevalence of vitamin D deficiency in chronic renal failure (CRF) patients on peritoneal dialysis (PD) and to correlate the findings with various demographic and renal osteodystrophy markers.

METHOD

This cross-sectional, multicenter study was carried out in 273 PD patients with a mean age of 61.7 +/- 10.9 years and mean duration of PD 3.3 +/- 2.2 years. It included 123 female and 150 male patients from 20 centers in Greece and Turkey, countries that are on the same latitude, namely, 36-42 degrees north. We measured 25(OH)D3 and 1.25(OH)2D3 levels and some other clinical and laboratory indices of bone mineral metabolism.

RESULTS

Of these 273 patients 92% (251 patients) had vitamin D deficiency i.e. serum 25(OH)D3 levels less than 15 ng/ml, 119 (43.6%) had severe vitamin D deficiency i.e., serum 25(OH)D3 levels, less than 5 ng/ml, 132 (48.4%) had moderate vitamin D deficiency i.e., serum 25(OH)D3 levels, 5-15 ng/ml, 12 (4.4%) vitamin D insufficiency i.e., serum 25(OH)D3 levels 15 - 30 ng/ml and only 10 (3.6%) had adequate vitamin D stores. We found no correlation between 25(OH)D3 levels and PTH, serum albumin, bone alkaline phosphatase, P, and Ca x P. In multiple regression analyses, the independent predictors of 25(OH)D3 were age, presence of diabetes (DM-CRF), levels of serum calcium and serum 1.25(OH)2D3.

CONCLUSION

We found a high prevalence (92%) of vitamin D deficiency in these 273 PD patients, nearly one half of whom had severe vitamin D deficiency. Vitamin D deficiency is more common in DM-CRF patients than in non-DM-CRF patients. Our findings suggest that these patients should be considered for vitamin D supplementation.

Deletion at 14q22-23 indicates a contiguous gene syndrome comprising anophthalmia, pituitary hypoplasia, and ear anomalies

Anophthalmia and pituitary gland hypoplasia are both debilitating conditions where the underlying genetic defect is unknown in the majority of cases. We identified a patient with bilateral anophthalmia and absence of the optic nerves, chiasm and tracts, as well as pituitary gland hypoplasia and ear anomalies with a de novo apparently balanced chromosomal translocation, 46,XY,t(3;14)(q28;q23.2). Translocation breakpoint analysis using FISH and high-resolution microarray comparative genomic hybridization (CGH) has identified a 9.66 Mb deleted region on the long arm of chromosome 14 which includes the genes BMP4, OTX2, RTN1, SIX6, SIX1, and SIX4. Three other patients with interstitial deletions involving 14q22-23 have been described, all with bilateral anophthalmia, pituitary abnormalities, ear anomalies, and a facial phenotype similar to our patient. OTX2 is involved in ocular developmental defects, and the severity of the ocular phenotype in our patient and the other 14q22-23 deletion patients, suggests this genomic region harbors other gene/s involved in ocular development. BMP4 haploinsufficiency is predicted to contribute to the ocular phenotype on the basis of its expression pattern and observed murine mutant phenotypes. In addition, deletion of BMP4 and SIX6 is likely to contribute to the abnormal pituitary development, and SIX1 deletion may contribute to the ear and other craniofacial features. This indicates that contiguous gene deletion may contribute to the phenotypic features in the 14q22-23 deletion patients.

N-Acetylglucosamine Reduces Inflammatory Response during Acute Peritonitis in Uremic Rats

BACKGROUND

Peritoneal dialysis (PD) induces intraperitoneal inflammation and that process may be uremia. The goal of this study is to evaluate the effect of uremia on the kinetics of peritonitis and furthermore test the anti-inflammatory potential of N-acetylglucosamine (NAG) in a uremic environment.

METHODS

Experiments were performed on healthy Wistar rats and on animals with impaired renal function. Acute PD was performed in all animals with dialysis fluid containing either glucose (GLU) or NAG as osmotic solutes. Peritonitis was induced by addition of lipopolysaccharide from Escherichia coli (LPS) to the dialysis fluid. Transperitoneal transport of water and solutes as well as intraperitoneal and systemic inflammation were evaluated.

RESULTS

Uremia reduces peritoneal permeability to total protein during peritonitis (-33% vs. control, p < 0.001) and increases net ultrafiltration (+2.5 +/- 2.2 vs. -2.7 +/- 3.2 ml in control, p < 0.001). In uremic rats with peritonitis, reduced dialysate levels of the following inflammatory mediators were detected as compared to healthy animals: MCP-1 (-15%, p < 0.01); IL-1beta (-53%, p < 0.001), and elastase (-28%, p < 0.02). In the serum of uremic rats, the increase in TNFalpha and MCP-1 concentrations was smaller than in control rats: -44% (p < 0.02) and -39% (p < 0.001), respectively. NAG used as an osmotic solute in rats with preserved renal function decreases intraperitoneal and systemic inflammation during acute peritonitis. Drained dialysate volume was increased in the NAG group by 32% (p < 0.001) and transperitoneal loss of protein was reduced by 21% (p < 0.002). When NAG was used as the osmotic solute instead of GLU, intraperitoneal inflammation in uremic animals was further reduced: TNFalpha (-40%, p < 0.05); IL-1beta (-49%, p < 0.005); MCP-1 (-21%, p < 0.005). The presence of NAG also reduced the increased blood level of IL-1beta (-47%,p < 0.02) and MCP-1 (-36%, p < 0.02).

CONCLUSIONS

Intensity of acute peritonitis is reduced during uremia. NAG exerts a systemic and peritoneal anti-inflammatory action under conditions of uremia that confirms the potential use of this compound as an osmotic agent in the PD fluids that also decreases inflammation.

N-Acetylglucosamine – An Osmotic Solute for Peritoneal Dialysis without Inducing Hyperinsulinemia

METHODS

N-Acetylglucosamine (NAG) was compared to glucose as an osmotic solute during peritoneal dialysis in rats. The effect of the tested solutes on blood glucose and insulin levels during dialysis was evaluated.

RESULTS

During 6-hour exchange with NAG (220 mmol/l) solution, the dialysate volume was higher than in rats dialyzed with fluid containing glucose (220 mmol/l; GLU: 34.5 +/- 1.7 vs. 32.8 +/- 1.1 ml, respectively; p < 0.05). The peritoneal permeability to protein (D/S x 1,000) was lower in the NAG group (9.7 +/- 2.5 vs. 16.3 +/- 5.6 in GLU; p < 0.02). Dialysis with GLU-based solution resulted in hyperglycemia up to 180 +/- 39 mg/dl; in the NAG group the increase in the blood glucose level was moderate (up to 91 +/- 9 mg/dl; p < 0.001). Dialysis with GLU fluid caused an increase in blood insulin level by 53.2 +/- 62.4 pmol/l, whereas the insulin blood concentration in NAG-treated animals was increased by 5.0 +/- 5.4 pmol/l (p < 0.001).

CONCLUSIONS

NAG is more effective than GLU osmotic solute during peritoneal dialysis and it reduces peritoneal permeability to protein. Dialysis with NAG results in lower hyperglycemia and hyperinsulinemia, both effects are favorable in diabetic peritoneal dialysis patients.

Effect of iron sucrose on human peritoneal mesothelial cells

BACKGROUND

Iron supplementation is often required in uraemic patients with anaemia. Peritoneal cavity was proposed as an alternative intravenous route for iron infusion in patients treated with peritoneal dialysis. We studied the effect of iron sucrose (Venofer) on the function of human peritoneal mesothelial cells maintained in in vitro culture.

MATERIALS AND METHODS

In in vitro experiments on human peritoneal, the mesothelial effect of elemental iron (in conc. 0.0001-1 mg mL-1) present in Venofer on their viability, growth and synthesis of IL-6 was studied. Additionally we evaluated with a fluorescent probe (2',7'-dichlorodihydro-fluorescein diacatate) generation of reactive oxygen species in cells exposed to iron sucrose. We also measured accumulation of iron in the cytoplasm of mesothelial cells after their in vitro exposure to Venofer.

RESULTS

In in vitro conditions iron induces a dose-dependent inhibition of viability of the mesothelial cells as reflected by inhibition of the cells growth by 34% at Fe 0.1 mg mL-1 vs. control (P < 0.05) increased release of lactate dehydrogenase (LDH) from the cytosol: 67.1 +/- 30.3 mU mL-1 at Fe 1 mg mL-1 vs. 7.9 +/- 6.4 in control group (P < 0.001), and reduced synthesis of IL-6: 209 +/- 378 pg mg-1 cell protein at Fe 1 mg mL-1 vs. 38674 +/- 4146 pg mg-1 cell protein in controls (P < 0.001). Cytotoxicity of iron towards mesothelial cells was enhanced in vitro when it was tested in presence of the dialysis fluid. Iron used in vitro at concentration 0.0001 mg mL-1 and greater induces generation of oxygen-derived free radicals in mesothelial cells. Furthermore, iron is taken by these cells and stored in their cytosol, resulting in stimulation of the intracellular generation of free radicals.

CONCLUSIONS

We conclude that iron used in the form of iron sucrose is cytotoxic to human peritoneal mesothelial cells. Accumulation of iron sucrose within cytoplasm of these cells may lead to induction of its chronic cytotoxic effect.

Replacement of glucose with N-acetylglucosamine in peritoneal dialysis fluid-experimental study in rats

BACKGROUND

Glucose is still used as an osmotic solute in peritoneal dialysis fluids, despite evidence of its local (peritoneal) and systemic toxicities. However a constant search is underway for a new, more biocompatible osmotic solute for peritoneal dialysis fluids.

OBJECTIVE

The present study evaluated N-acetylglucosamine (NAG) in a concentration of 220 mmol/L as an alternative to glucose for the osmotic solute in peritoneal dialysis fluid, during chronic peritoneal dialysis in rats.

METHODS

For 8 weeks, male Wistar rats were infused with glucose-based or NAG-based dialysis fluid. Intraperitoneal inflammation and peritoneal permeability and morphology were evaluated in all rats during the study.

RESULTS

Repeated intraperitoneal infusion of the NAG-based dialysis fluid resulted in a weaker intra-abdominal inflammatory reaction as compared with the reaction in rats infused with glucose-based dialysis solution. At the end of the study, the concentration of hyaluronan in the peritoneal interstitium obtained from NAG-treated rats was higher than that found in the interstitium taken from animals exposed to dialysis fluid containing glucose. Also, peritoneal permeability to total protein was lower in NAG-treated rats.

CONCLUSION

As an alternative to glucose, NAG used for the osmotic solute in peritoneal dialysis solution decreases the intraperitoneal inflammatory reaction induced by the process of peritoneal dialysis and, indirectly (owing to the increased hyaluronan content in the peritoneal interstitium), diminishes peritoneal permeability to protein.

Chronic peritoneal dialysis in octogenarians

BACKGROUND

During the past few decades the pattern of end-stage renal failure disease has changed with increasing number of elderly patients admitted for dialysis. In spite of their increasing number, little is known about the optimal mode of therapy of the 'old old' (those >or=80 years) patients.

METHODS

In this retrospective study, we analysed the results of treatment of 31 non-institutionalized 'old old' patients at Toronto Western Hospital (17) and Scarborough General Hospital (14) and seven institutionalized patients in chronic care, Riverdale Hospital. The patients were on CAPD with Twin-bag Baxter (28) or Home Choice, Baxter or Fresenius CCPD system (10). Patients were screened at the CAPD clinic when routine blood investigations were done. Patient and technique survival, initial and final laboratory data (last visit or before death) and complications related/unrelated to dialysis method are presented.

RESULTS

Multiple comorbid conditions were present at the start of the treatment and new added during treatment; very few were dialysis-related. The majority of non-institutionalized patients required assistance of home-care nurse to perform dialysis. Peritonitis (1/28.6 patient months) and exit-site infection rate (1/75.1 patient months) were low and responded to treatment. Incidence of peritonitis was higher among institutionalized debilitated patients (1/5.3 patient months). Incidence of hospitalization was 1/14.7 patient months and patients spent in hospital 7.5 days/patient year. Forty-seven per cent of patients survived 24 months; 39% survived 30 months. Technique survival was 91.5% at 12 months and 81.4% at 30 months. Poor appetite and malnutrition were frequent among very old patients. Patients and their families were motivated for treatment and discontinuation of dialysis was not higher than described elsewhere in literature.

CONCLUSIONS

This study has demonstrated that chronic peritoneal dialysis could be recommended as a safe and suitable modality of treatment of end-stage renal failure in old old patients.

The early neural plate rules over the mesoderm

In this issue of Developmental Cell, Richard Harland and colleagues describe evidence that an inductive interaction between the neural plate and the paraxial mesoderm regulates somite development and somite size.

Genetic and developmental analysis of X-inactivation in interspecific hybrid mice suggests a role for the Y chromosome in placental dysplasia

It has been shown previously that abnormal placental growth, i.e., hyper- and hypoplasia, occurs in crosses and backcrosses between different mouse (Mus) species. A locus that contributes to this abnormal development has been mapped to the X chromosome. Unexpectedly, an influence of fetal sex on placental development has been observed, in that placentas attached to male fetuses tended to exhibit a more pronounced phenotype than placentas attached to females. Here, we have analyzed this sex dependence in more detail. Our results show that differences between male and female placental weights are characteristic of interspecific matings and are not observed in intraspecific Mus musculus matings. The effect is retained in congenic lines that contain differing lengths of M. spretus-derived X chromosome. Expression of the X-linked gene Pgk1 from the maternal allele only and lack of overall activity of two paternally inherited X-linked transgenes indicate that reactivation or lack of inactivation of the paternal X chromosome in trophoblasts of interspecific hybrids is not a frequent occurrence. Thus, the difference between male and female placentas seems not to be caused by faulty preferential X-inactivation. Therefore, these data suggest that the sex difference of placental weights in interspecific hybrids is caused by interactions with the Y chromosome.

Stabilized plasmid-lipid particles for systemic gene therapy

The structure of 'stabilized plasmid-lipid particles' (SPLP) and their properties as systemic gene therapy vectors has been investigated. We show that SPLP can be visualized employing cryo-electron microscopy to be homogeneous particles of diameter 72 +/- 5 nm consisting of a lipid bilayer surrounding a core of plasmid DNA. It is also shown that SPLP exhibit long circulation lifetimes (circulation half-life >6 h) following intravenous (i.v.) injection in a murine tumor model resulting in accumulation of up to 3% of the total injected dose and concomitant reporter gene expression at a distal (hind flank) tumor site. In contrast, i v. injection of naked plasmid DNA or plasmid DNA-cationic liposome complexes did not result in significant plasmid delivery to the tumor site or gene expression at that site. Furthermore, it is shown that high doses of SPLP corresponding to 175 microg plasmid per mouse are nontoxic as assayed by monitoring serum enzyme levels, whereas i.v. injection of complexes give rise to significant toxicity at dose levels above 20 microg plasmid per mouse. It is concluded that SPLP exhibit properties consistent with potential utility as a nontoxic systemic gene therapy vector.

X inactivation in the mouse embryo deficient for Dnmt1: distinct effect of hypomethylation on imprinted and random X inactivation

It has been suggested that DNA methylation plays a crucial role in genomic imprinting and X inactivation. Using DNA methyltransferase 1 (Dnmt1)-deficient mouse embryos carrying X-linked lacZ transgenes, we studied the effects of genomic demethylation on X inactivation. Based on the expression pattern of lacZ, the imprinted X inactivation in the visceral endoderm, a derivative of the extraembryonic lineage, was unaffected in Dnmt1 mutant embryos at the time other imprinted genes showed aberrant expression. Random X inactivation in the embryonic lineage of Dnmt1 mutant embryos, however, was unstable as a result of hypomethylation, causing reactivation of, at least, one lacZ transgene that had initially been repressed. Our results suggest that maintenance of imprinted X inactivation in the extraembryonic lineage can tolerate extensive demethylation while normal levels of methylation are required for stable maintenance of X inactivation in the embryonic lineage.

Suppression of cytokine production and cell adhesion molecule expression in human monocytic cell line THP-1 by Tripterygium wilfordii polysaccharide moiety

Extracts of the vine-like plant Tripterygium wilfordii (TW) have been widely used in China as an immunosuppressant and anti-inflammatory drug for the treatments of rheumatoid arthritis, lupus erythematosus and other inflammatory disorders. In this study the molecular mechanisms of action of three TW extracts (ethanol, aqueous, polysaccharide) on the expression of inflammatory cytokines and adhesion molecules were investigated by RT-PCR and immunofluorescence binding techniques. The lipopolysaccharide (LPS)-mediated stimulatory effects of tumor necrosis factor-alpha (TNF-alpha) cytokine production and cell adhesion molecule (CD11c, CD18, CD14, CD54) expression in human monocytic THP-1 cells were modulated by treatments of the TW extracts or tacrolimus (FK506). The TW polysaccharide moiety exhibited more profound immunosuppressive properties than the aqueous and ethanol extracts. Biochemical characterization of the polysaccharide moiety revealed a major molecular weight of 22 kDa (viz. PSP22). The PSP22 was found to be a potential immunosuppressant that manifests the necessary immunomodulating properties.

Stabilized plasmid-lipid particles: pharmacokinetics and plasmid delivery to distal tumors following intravenous injection

A previous study has shown that plasmid DNA can be encapsulated in lipid particles (SPLP, "stabilized plasmid lipid particles") of approximately 70 nm diameter composed of 1,2-dioleoyl-3-phosphatidyl-ethanolamine (DOPE), the cationic lipid N,N-dioleoyl-N,N-dimethylammonium chloride (DODAC) and poly(ethylene glycol) conjugated to ceramide (PEG-Cer) using a detergent dialysis process (Wheeler et al. (1999) Gene Therapy 6, 271-281). In this work we evaluated the potential of these SPLPs as systemic gene therapy vectors, determining their pharmacokinetics and the biodistribution of the plasmid and lipid components. It is shown that the blood clearance and the biodistribution of the SPLPs can be modulated by varying the acyl chain length of the ceramide group used as lipid anchor for the PEG polymer. Circulation lifetimes observed for SPLPs with PEG-CerC14 and PEG-CerC20 were t(1/2) = approximately 1 and approximately 10 h, respectively. The SPLPs are stable while circulating in the blood and the encapsulated DNA is fully protected from degradation by serum nucleases. The accelerated clearance of SPLPs with PEG-CerC14 is accompanied by increased accumulation in liver and spleen as compared to PEG-CerC20 SPLPs. Delivery of intact plasmid to liver and spleen was detected. Significant accumulation (approximately 10% of injected dose) of the long circulating SPLPs with PEG-CerC20 in a distal tumor (Lewis lung tumor in the mouse flank) was observed following i.v. application and delivery of intact plasmid to tumor tissue at approximately 6% injected dose/g tissue is demonstrated.

The effect of N-acetylglucosamine as a substrate for in vitro synthesis of glycosaminoglycans by human peritoneal mesothelial cells and fibroblasts

The effect of N-acetylglucosamine (NAG) on in vitro synthesis of glycosaminoglycans by human peritoneal mesothelial cells and fibroblasts was studied. In contrast to isosmotic concentrations of glucose, NAG increases the synthesis of hyaluronan by mesothelial cells and fibroblasts in a dose-dependent manner. This effect of NAG can be demonstrated in the presence of increased glucose levels in a medium, or in a medium mixed with effluent dialysate obtained from continuous ambulatory peritoneal dialysis (CAPD) patients. Glucose inhibits synthesis of sulphated glycosaminoglycans by peritoneal mesothelial cells and fibroblasts, whereas NAG stimulates their production. Our results demonstrate that NAG is an effective stimulator of the in vitro glycosaminoglycans synthesis by human peritoneal mesothelial cells and fibroblasts.

Residual bladder dysfunction 2 to 10 years after acute transverse myelitis

OBJECTIVE

Acute transverse myelitis (ATM) is a relatively rare condition in children. The recovery rate is reported to be generally complete. In the current study, the long-term urological outcome of children with ATM was assessed.

METHODOLOGY

The medical records of children with ATM admitted to Queen Mary Hospital, Hong Kong, over the last 15 years, were reviewed.

RESULTS

The median age of the five children with ATM at the time of onset was 6 years (range = 2-12 years). The median length of follow up was 5 years (2-10 years). Four children recovered completely from paraparesis; two had no urinary symptoms with normal micturition. However, video-urodynamic studies 3 years after the acute onset revealed that four out of the five children, including one without any urinary symptom, suffered from residual bladder dysfunction - two from contractile neurogenic bladder and two from intermediate type of neurogenic bladder.

CONCLUSION

Residual bladder dysfunction is common in children suffering from ATM despite improvement of paraparesis and apparent lack of urological symptoms. Long-term follow up of urological function in these patients is recommended.