Shotgun Glycomics Identifies Tumor-Associated Glycan Ligands Bound by an Ovarian Carcinoma-Specific Monoclonal Antibody

Cancers display distinctive carbohydrate molecules (glycans) on their surface proteins and lipids. mAb A4, an in-house generated monoclonal IgM antibody, is capable of distinguishing malignant ovarian carcinoma cells from benign ovarian epithelia by binding specifically to cancer cell-associated glycans. However, the structural details of the glycan targets of mAb A4 have been elusive. Here we developed a novel approach of isolating and fractionating glycan molecules released from glycoproteins in cancer cell lysates using HILIC-UPLC, and used them as probes on a microarray for affinity-based identification of the binding targets, allowing full-size, difficult to synthesize, cancer-associated glycans to be directly studied. As a result of this "shotgun" glycomics approach, we corroborate the previously assigned specificity of mAb A4 by showing that mAb A4 binds primarily to large (>15 glucose units), sialylated N-glycans containing the H-type 1 antigen (Fuc-α1,2-Gal-β1,3-GlcNAc). Although mAb A4 was also capable of directly binding to type 1 N-acetyl-lactosamine, this epitope was mostly shielded by sialylation and thus relatively inaccessible to binding. Knowledge of the structure of mAb A4 antigen will facilitate its clinical development as well as its use as a diagnostic biomarker.

Analysis of Models Predicting Morphology Transitions in Reactive Twin-Screw Extrusion of Bio-Based Polyester/Polyamide Blends

Immiscible PLA/PA11 of 80/20 and 50/50 wt% were compatibilized through addition of p-toluenesulfonic acid (TsOH) catalyst in reactive ultra-high speed twin-screw extrusion. Two mixing screw designs were compared for their ability to disperse the PA11 droplets in the PLA matrix as a function of screw speed up to 2000 rpm. The size and polydispersity of droplets of dispersed PA11 decreased when a high shear (HS) screw was used, whereas broad droplet size distribution was produced in the low shear (LS) screw. Two models predicting the droplet size dependence on shear rate, viscosity ratio and interfacial tension were fit to the experimental data. The Serpe model including volume fraction effects produced a better fit compared to the Wu model, which does not include volume fraction effects. Mechanical testing indicated that the compatibility of PLA/PA11 blends was improved through addition of TsOH catalyst for 50/50 wt% blends due to ester – amide exchange reactions at the interfaces in the immiscible PLA and PA11 phases. The enhancement of ductility was greater after processing with the LS screw configuration than the HS screw configuration. The inferior properties after high shear mixing were likely due to molecular weight degradation during processing. While the aggressive shear in the HS screw design resulted in fine dispersion, care should be taken to minimize degradation, especially for shear sensitive polymers.

Solvent-resistant polyetherimide network systems via phenylethynylphthalic anhydride endcapping

The synthesis and characterization of a highly processable thermosetting polyimide system based on 22'-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride or bisphenol A dianhydride (BPA-DA) endcapped with 4-phenylethynylphthalic anhydride is described. The system afforded oligomers that were readily melt processable at high curing temperatures (380-420 CC). Imide oligomers ranging from MR = 2000 to 40 000 g molI and copolyimides were synthesized using the ester acid of the dianhydrides and either meta- and/or para-phenylene diamines as comonomers via solution imidization techniques. The oligomers were shown to display low melt viscosity values and to flow under low pressure during compression moulding. The thermally cured polymers formed tough creasable films and displayed excellent solvent resistance which was correlated to their high gel fractions (>95%). Very significant increases in glass transition temperatures were observed after cure of a 3000., oligomer. The mera-phenylene diamine-based polymer exhibited a cured Ts approximately 30C lower (233C) than the para:meta (70:30) system (267C). The all para-phenylene diamine-based homopolymers could be completely cyclized in solution but crystallized at room temperature to produce fine insoluble powders. The resulting moderately semicrystalline homopolymer showed a TM of up to 321 'C which was not observed on the second heating. These polyimides also show excellent thermal stability as judged by thermogravimetric analysis (TGA) and are being examined as structural adhesives and matrix resins.

Discharge documentation improvement project: a pilot study

BACKGROUND

Discharge summaries remain a critical communication tool with primary care physicians. In a previous study of over 200 general medicine discharge summaries, we demonstrated that only 50% contain information regarding the indication and follow up required of any medicine changes on discharge.

AIM

In this follow up pilot study, we assess the role of feedback and token incentives in improving discharge documentation.

METHODS

Over a 14-week period, we randomly audited a selection of discharge summaries on a fortnightly basis. The results of these audits were fed back to the junior medical staff who compiled these summaries. If over 80% of the audited discharge summaries adequately documented the indication, with required follow up for new medication changes, junior doctors were provided with a token, non-monetary incentive for their efforts. At the end of the study period, we then conducted a survey of the junior doctors involved and collected feedback regarding their impressions of the study.

RESULTS

Over the study period, 722 discharge summaries were completed and eligible for analysis. Over this time, mean appropriate documentation regarding medicine indication improved by 32%, and follow-up documentation improved by 10%. Overall, the participants felt the interventions were beneficial and that they should be continued beyond the study period.

CONCLUSIONS

Education coupled with regular feedback and non-monetary incentives can potentially lead to improvements in the quality of discharge summaries.

Intraperitoneal Administration of Low Dose Aluminium in The Rat: How Good is It to Produce a Model for Alzheimer Disease

Since neurotoxicity of aluminium (Al) resembles the progressive neurodegeneration observed in Alzheimer Disease (AD), Al administration in several ways has been used to produce AD model. Intraperitoneal (ip) low dose (4.2 mg/ kg) Al injection in rats for long periods is the preferred method by some researchers. In this paper, the efficiency of this method for producing an AD model was evaluated. In this study, we looked at the neuropathology of Al and the characteristic lesions of AD by histological and immunohistochemical techniques and determined oxidative stress markers in the brains of Al-treated and control rats. We also made electrophysiological recordings at the hippocampus and evaluated possible behavioural changes by Morris water maze test. However, no pathologic changes occurred in the animals except for an impairment in long-term potentiation (LTP) in the hippocampus (e.g. the LTPs of population spike (PS) amplitude at 15 min post-tetanus were measured as 217±27% in Al-treated rats and as 240±42% in sham-treated rats, of baseline PS amplitude). According to the findings of the present study, low dose of ip Al in rats is not sufficient to produce a good AD model. Higher doses (≥10 mg/kg) should be used.

Effects of multiple ascending doses of the glucagon receptor antagonist PF-06291874 in patients with type 2 diabetes mellitus

AIMS

To assess the pharmacokinetics, pharmacodynamics, safety and tolerability of multiple ascending doses of the glucagon receptor antagonist PF-06291874 in patients with type 2 diabetes mellitus (T2DM).

METHODS

Patients were randomized to oral PF-06291874 or placebo on a background of either metformin (Part A, Cohorts 1-5: 5-150 mg once daily), or metformin and sulphonylurea (Part B, Cohorts 1-2: 15 or 30 mg once daily) for 14-28 days. A mixed-meal tolerance test (MMTT) was administered on days -1 (baseline), 14 and 28. Assessments were conducted with regard to pharmacokinetics, various pharmacodynamic variables, safety and tolerability. Circulating amino acid concentrations were also measured.

RESULTS

PF-06291874 exposure was approximately dose-proportional with a half-life of ∼19.7-22.7 h. Day 14 fasting plasma glucose and mean daily glucose values were reduced from baseline in a dose-dependent manner, with placebo-corrected decreases of 34.3 and 42.4 mg/dl, respectively, at the 150 mg dose. After the MMTT, dose-dependent increases in glucagon and total glucagon-like peptide-1 (GLP-1) were observed, although no meaningful changes were noted in insulin, C-peptide or active GLP-1 levels. Small dose-dependent increases in LDL cholesterol were observed, along with reversible increases in serum aminotransferases that were largely within the laboratory reference range. An increase in circulating gluconeogenic amino acids was also observed on days 2 and 14. All dose levels of PF-06291874 were well tolerated.

CONCLUSION

PF-06291874 was well tolerated, has a pharmacokinetic profile suitable for once-daily dosing, and results in reductions in glucose with minimal risk of hypoglycaemia.

Distribution of common pathogens in patients with pyogenic liver abscess in China: a meta-analysis

Pyogenic liver abscess (PLA) is a potentially life-threatening disease in many parts of the world, especially in Asia. The aim of this study was to quantify the proportion of common pathogens in patients with PLA in China, using a meta-analysis method based on systematic review of published studies. Several electronic databases were searched to identify the studies reporting the pathogens of PLA. We performed a meta-analysis to calculate the pooled proportion of pathogens and subgroup analysis among the included studies using R 3.1.1 software. In total, 183 studies were included in our final analysis, Klebsiella spp (54 %), Escherichia spp (29 %), Enterobacter spp (9 %), Proteus spp (6 %) and Pseudomonas spp (5 %) comprised the major gram-negative bacteria. Gram-positive bacteria mainly included Staphylococcus spp (13 %), Streptococcus spp (8 %) and Enterococcus spp (7 %). The distribution of pathogens in PLA patients were different in different economic regions in China. The proportion of Klebsiella spp had an upward tendency in recent years compared to other pathogens. In addition, the proportion of common pathogens in PLA patients with diabetes mellitus (DM) were carried out indicating that the dominant pathogens were Klebsiella spp (66 %), Escherichia spp (21 %) and Enterobacter spp (11 %). This meta-analysis showed that the main pathogens of PLA were Klebsiella spp, Escherichia spp, Staphylococcus spp, and Enterobacter spp in China. To ensure a precise estimate of the epidemiology of the pathogens, further large-scale or even a population-based study is needed.

Heart Failure Clinics in the Netherlands in 2003

PURPOSE

Heart failure (HF) care in the Netherlands is going through a lot of changes. Nurses have increasingly important roles in providing optimal care for these chronically ill patients. In this study, we describe the current number of HF management programs and the role of the nurses in these programs.

METHOD

Data were collected by a national survey as part of a European HF clinic survey of the UNITE study group of the Working Group on Cardiovascular Nursing between February and March 2003 to 142 hospitals in the Netherlands.

RESULTS

In 60% of the hospital locations, there is a HF management program. Most of the programs are organized as HF outpatient clinics. In all HF programs, cardiologists and nurses are involved. Other health care providers involved are, amongst others, general practitioners (29%), dieticians (59%), physical therapists (47%), social workers (30%) and psychologists (17%). All programs offer follow-up after discharge from the hospitals and in most of the programs patients have increased access to a health care provider. Behavioural interventions (68%), psychosocial counselling (64%), patient education (88%) and support of the informal caregivers (59%) are important components. In 90% of the programs (restricted), physical examination is the responsibility of the HF nurse and in 65% of the programs nurses are involved in optimizing medical treatment. Financial support and education of HF nurses is still unstructured and diverse.

CONCLUSION

There is a rise in the number of HF programs in the Netherlands. There is diversity in content and intensity of these programs and the role of the nurse is not clearly defined yet. Research and discussion on the subject of optimal effective HF care and the role of the HF nurse is still needed.