Factor XII interacts with the multiprotein assembly of urokinase plasminogen activator receptor, gC1qR, and cytokeratin 1 on endothelial cell membranes

Investigations were performed to define the factor XII (FXII) binding site(s) on cultured endothelial cells (HUVECs). Biotin- or fluorescein isothiocyanate (FITC)-FXII in the presence of 10 microM Zn(2+) specifically binds to HUVEC monolayers or cells in suspension. Collagen-stimulated platelets release sufficient Zn(2+) to support FXII binding. On laser scanning confocal microscopy or electron microscopy, FITC-FXII or Nanogold-labeled FXII, respectively, specifically bind to HUVECs. Antibodies to gC1qR, urokinase plasminogen activator receptor (uPAR) and, to a lesser extent, cytokeratin 1 (CK1) block FXII binding to HUVECs as determined by flow cytometry and soluble or solid phase binding assays. FITC-FXII on endothelial cells colocalizes with gC1qR, uPAR and, to a lesser extent, CK1 antigen. Combined recombinant soluble uPAR and CK1 inhibit 80% FITC-FXII binding to HUVECs. Peptide Y(39)HKCTHKGR(47) (YHK9) from the N-terminal region of FXII and peptide H(479)KHGHGHGKHKNKGKKNGKH(498) from HK's domain 5 cell-binding site block FITC-FXII binding to HUVECs. Peptide YHK9 also inhibits FXIIa's activation of prekallikrein and FXI on HUVECs. These combined investigations indicate that FXII through a region on its fibronectin type II domain binds to the same multiprotein receptor complex that comprises the HK binding site of HUVECs. However, plasma concentrations of HK and vitronectin inhibit FXII binding to HUVECs 100% and 50%, respectively, and plasma albumin and other proteins prevent a sufficient level of free Zn(2+) to be available to support FXII binding to HUVECs. Thus, physiologic FXII expression on HUVECs is secondary to HK binding and highly restricted in its ability to initiate prekallikrein or FXI activation.     

Novel Redox-Responsive Amphiphilic Copolymer Micelles for Drug Delivery: Synthesis and Characterization

A novel redox-responsive amphiphilic polymer was synthesized with bioreductive trimethyl-locked quinone propionic acid for a potential triggered drug delivery application. The aim of this study was to synthesize and characterize the redox-responsive amphiphilic block copolymer micelles containing pendant bioreductive quinone propionic acid (QPA) switches. The redox-responsive hydrophobic block (polyQPA), synthesized from QPA-serinol and adipoyl chloride, was end-capped with methoxy poly(ethylene glycol) of molecular weight 750 (mPEG₇₅₀) to achieve a redox-responsive amphiphilic block copolymer, polyQPA-mPEG₇₅₀. PolyQPA-mPEG₇₅₀ was able to self-assemble as micelles to show a critical micelle concentration (CMC) of 0.039% w/v (0.39 mg/ml, 0.107 mM) determined by a dye solubilization method using 1,6-diphenyl-1,3,5-hexatriene (DPH) in phosphate-buffered saline (PBS). The mean diameter of polymeric micelles was found to be 27.50 nm (PI = 0.064) by dynamic light scattering. Furthermore, redox-triggered destabilization of the polymeric micelles was confirmed by ¹H-NMR spectroscopy and particle size measurements in a simulated redox state. PolyQPA-mPEG₇₅₀ underwent triggered reduction to shed pendant redox-responsive QPA groups and its polymeric micelles were swollen to be dissembled in the presence of a reducing agent, thereby enabling the release of loaded model drug, paclitaxel. The redox-responsive polyQPA-mPEG₇₅₀ polymer micelles would be useful as a drug delivery system allowing triggered drug release in an altered redox state such as tumor microenvironments with an altered redox potential and/or redox enzyme upregulation.KEY WORDS: amphiphilic polymer, micelle, redox-responsive polymer, targeted drug delivery, trimethyl-locked quinone propionic acid     

The BiZiFED project: Biofortified zinc flour to eliminate deficiency in Pakistan

Zinc deficiency is a global public health problem, affecting ~17% of the world's population, with the greatest burden in low‐ and middle‐income countries. An increasing body of evidence suggests that biofortification may be a cost‐effective and sustainable approach to reducing zinc and other micronutrient deficiencies. Biofortification enhances the nutritional quality of food crops through conventional plant breeding techniques and agronomic practices. This paper presents ongoing research on biofortification in Pakistan, where over 40% of women are zinc deficient. The Biofortified Zinc Flour to Eliminate Deficiency (BiZiFED) project aims to investigate the impact of biofortification as a strategy to alleviate zinc deficiency in Pakistan. The project is supported by the Biotechnology and Biological Sciences Research Council (BBSRC) Global Challenges Research Fund from May 2017 to April 2019. This paper outlines the four objectives and work packages within the BiZiFED project: (1) a double‐blind, randomised controlled trial to examine the effect of consuming flour made from a high zinc variety of biofortified wheat (Zincol‐2016/NR‐421) on dietary zinc intake and status; (2) a cost‐effectiveness study to assess the health and economic impact of agronomic biofortification of wheat; (3) a mixed methods study to explore the cultural acceptability and sustainability of biofortification in Pakistan; (4) capacity building and development of long‐term research partnerships in Pakistan. The findings will contribute to the evidence base for the potential impact of biofortification to alleviate zinc deficiency among the poorest communities.     

In vitro Adhesion of Oral Candida dubliniensis Isolates to Acrylic Denture Surfaces following Brief Exposure to Sub-Cidal Concentrations of Polyenes,Azoles and Chlorhexidine

Objectives

We aimed to investigate the effect of brief exposure to sub-cidal concentrations of nystatin, amphotericin B, ketoconazole, fluconazole and chlorhexidine gluconate on the adhesion of oral Candida dubliniensis isolates to the surface of acrylic dentures.

Methods

After determining the minimum inhibitory concentration of each drug, 20 oral isolates of C. dubliniensis were exposed to sub-cidal concentrations of the drugs for 1 h. The drugs were then removed by dilution, and the adhesion of the isolates to denture acrylic strips was assessed by an in vitro adhesion assay.

Results

Compared to the controls, exposure to nystatin, amphotericin B, ketoconazole, fluconazole and chlorhexidine gluconate suppressed the ability of C. dubliniensis isolates to adhere to acrylic denture surfaces with a reduction of 74.68, 74.27, 57.31, 44.57 and 56.53% (p < 0.001 for all drugs), respectively.

Conclusions

Brief exposure to sub-cidal concentrations of anti-mycotics suppressed the adhesion of C. dubliniensis oral isolates to acrylic denture surfaces.Key Words: Candida dubliniensis, Nystatin, Amphotericin B, Ketoconazole, Fluconazole, Chlorhexidine, Acrylic dentures     

Ambulance use in Pakistan: an analysis of surveillance data from emergency departments in Pakistan

Background

The utilization of ambulances in low- and middle-income countries is limited. The aim of this study was to ascertain frequency of ambulance use and characteristics of patients brought into emergency departments (EDs) through ambulance and non-ambulance modes of transportation.

Methods

The Pakistan National Emergency Departments Surveillance (Pak-NEDS) was a pilot active surveillance conducted in seven major tertiary-care EDs in six main cities of Pakistan between November 2010 and March 2011. Univariate and multivariate logistic regression was performed to investigate the factors associated with ambulance use.

Results

Out of 274,436 patients enrolled in Pak-NEDS, the mode of arrival to the ED was documented for 94. 9% (n = 260,378) patients, of which 4.1% (n = 10,546) came to EDs via ambulances. The mean age of patients in the ambulance group was significantly higher compared to the mean age of the non-ambulance group (38 ± 18.4 years versus 32.8 ± 14.9 years, p-value < 0.001). The most common presenting complaint in the ambulance group was head injury (12%) while among non-ambulance users it was fever (12%). Patients of all age groups were less likely to use an ambulance compared to those >45 years of age (p-value < 0.001) adjusted for gender, cities, hospital type, presenting complaint group and disposition. The adjusted odds ratio of utilizing ambulances for those with injuries was 3.5 times higher than those with non-injury complaints (p-value < 0.001). Patients brought to the ED by ambulance were 7.2 times more likely to die in the ED than non-ambulance patients after adjustment for other variables in the model.

Conclusion

Utilization of ambulances is very low in Pakistan. Ambulance use was found to be more among the elderly and those presenting with injuries. Patients presenting via ambulances were more likely to die in the ED.