Environmental sampling for SARS-CoV-2 at a reference laboratory and provincial hospital in central Viet Nam, 2020

@#Objective: To determine whether environmental surface contamination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred at a provincial hospital in Viet Nam that admitted patients with novel coronavirus disease 2019 (COVID-19) and at the regional reference laboratory responsible for confirmatory testing for SARS-CoV-2 in 2020. Methods: Environmental samples were collected from patient and staff areas at the hospital and various operational and staff areas at the laboratory. Specimens from frequently touched surfaces in all rooms were collected using a moistened swab rubbed over a 25 cm2 area for each surface. The swabs were immediately transported to the laboratory for testing by real-time reverse transcription polymerase chain reaction (RT-PCR). Throat specimens were collected from staff at both locations and were also tested for SARS-CoV-2 using real-time RT-PCR. Results: During the sampling period, the laboratory tested 6607 respiratory specimens for SARS-CoV-2 from patients within the region, and the hospital admitted 9 COVID-19 cases. Regular cleaning was conducted at both sites in accordance with infection prevention and control (IPC) practices. All 750 environmental samples (300 laboratory and 450 hospital) and 30 staff specimens were negative for SARS-CoV-2. Discussion: IPC measures at the facilities may have contributed to the negative results from the environmental samples. Other possible explanations include sampling late in a patient’s hospital stay when virus load was lower, having insufficient contact time with a surface or using insufficiently moist collection swabs. Further environmental sampling studies of SARS-CoV-2 should consider including testing for the environmental presence of viruses within laboratory settings, targeting the collection of samples to early in the course of a patient’s illness and including sampling of confirmed positive control surfaces, while maintaining appropriate biosafety measures.

Evaluation of drug information databases for personal digital assistants.

PURPOSE: Core and supplemental drug information databases available for use with personal digital assistants (PDAs) were evaluated. METHODS: Ten core (or standalone) databases, six drug interaction analyzers, and three dietary supplement databases used with the Palm and Pocket PC operating systems were selected for study. The databases were rated for scope (the absence or presence of an answer to a drug information question), completeness (the comprehensiveness of an answer), and ease of use (the number of hypertext links needed to reach the desired answer). A total of 14 weighted categories, consisting of 146 and 30 drug questions for the core and supplemental databases, respectively, were used to determine the overall scores. RESULTS: The best overall performers were, in order of total scores, Lexi-Drugs Platinum, Tarascon Pocket Pharmacopoeia, ePocrates Rx Pro, and Clinical Pharmacology OnHand. The databases with the lowest composite scores were Triple i Prescribing Guide and A2Z Drugs. CONCLUSION: Drug information databases for PDAs varied in scope, completeness, and ease of use. The results may help clinicians find the most appropriate product for their practice setting.

Cases of scrapie with unusual features in Norway and designation of a new type, Nor98.

Five cases of scrapie with unusual features have been diagnosed in Norway since 1998. The affected sheep showed neurological signs dominated by ataxia, and had the PrP genotypes homozygous A136 H154 Q171/ A136H154Q171 or heterozygous A136H154Q171/A136R154Q171, which are rarely associated with scrapie. Brain histopathology revealed neuropil vacuolisation essentially in the cerebellar and cerebral cortices; vacuolation was less prominent in the brainstem, and no lesions were observed at the level of the obex. The deposits of PrPSc were mainly in the cortex of the cerebellum and cerebrum, and no PrPSC was detectable by immunohistochemistry and ELISA in the lymphoid tissues investigated. Western blot analysis showed that the glycotype was different from other known scrapie strains and from the BSE strain. From a diagnostic point of view, these features indicate that this type of scrapie, designated Nor98, could have been overlooked and may be of significance for sampling in scrapie surveillance programmes.

Inhomogeneous alginate gel spheres: an assessment of the polymer gradients by synchrotron radiation-induced X-ray emission, magnetic resonance microimaging, and mathematical modeling.

It has been previously demonstrated that calcium alginate gels prepared by dialysis often exhibit a concentration inhomogeneity being the polymer concentration considerably lower in the center of the gel than at the edges. Inhomogeneity may be a preferred structure in microcapsules due to low porosity and higher stability so that it is interesting to evaluate the polymer gradient in spherically symmetrical small alginate beads (1.0-0.7 mm diameter) obtained in different conditions. In this paper, two complementary techniques have been used to investigate this aspect. The concentration gradient of alginate has been analyzed by measuring both the spatial distribution of calcium ions in sections of alginate gel spheres, by means of x-ray fluorescence spectroscopy, and the T2 relaxation behavior on intact gel beads using magnetic resonance microimaging. The experimentally determined gradients from three-dimensional gels provide data to reevaluate the parameter estimates in the recently reported mathematical model for alginate gel formation (A. Mikkaelsen and A. Elgsaeter, Biopolymers, 1995, Vol. 36, pp. 17-41). The model may account for the gels being less inhomogeneous when nongelling sodium or magnesium ions are added during gelation.

Effect of daily and weekly micronutrient supplementation on micronutrient deficiencies and growth in young Vietnamese children.

BACKGROUND: Micronutrient deficiencies remain common in preschool children in developing countries. Interventions focus on single micronutrients and often lack effectiveness. Weekly instead of daily supplementation may improve effectiveness. OBJECTIVE: The efficacy of weekly and daily supplementation in reducing anemia prevalence and in improving the zinc, vitamin A, and growth status of 6-24-mo-old Vietnamese children was investigated. DESIGN: In this double-blind, placebo-controlled trial, the daily group (n = 55) received 8 mg elemental Fe (as iron sulfate), 5 mg elemental Zn (as zinc sulfate), 333 microg retinol, and 20 mg vitamin C 5 d/wk for 3 mo. The weekly group (n = 54) received 20 mg Fe, 17 mg Zn, 1700 microg retinol, and 20 mg vitamin C once a week. A third group (n = 54) received a placebo only. Venous blood samples were collected at the start and end of the supplementation period and anthropometric measurements were taken at the start and 3 mo after the end of supplementation. RESULTS: At baseline, 45.6% of subjects had hemoglobin concentrations < 110 g/L, 36.3% had zinc concentrations < 10.71 micromol/L, and 45.6% had retinol concentrations <0.70 micromol/L. Hemoglobin, retinol, and zinc concentrations of both the weekly and daily groups increased similarly compared with the placebo group (P < 0.001). There was no significant difference in growth between the supplemented groups and the placebo group. However, the height-for-age of subjects stunted at baseline increased with z scores of 0.48 (P < 0.001) and 0.37 (P < 0.001) for the daily and weekly groups, respectively. CONCLUSIONS: Weekly and daily supplementation improved hemoglobin, zinc, and retinol concentrations similarly. Neither intervention affected growth of the overall population, but growth of children stunted at baseline was improved through both types of supplementation.

Alginate polylysine microcapsules as immune barrier: permeability of cytokines and immunoglobulins over the capsule membrane.

Transplantation of pancreatic islets in alginate polylysine microcapsules is a potential useful method for treating type I diabetes. In this study, the permeability for alginate-polylysine microcapsules to cytokines an immunoglobulines has been investigated by a newly developed method. Magnetic monodisperse polymer particles (Dynabeads) coated with antibodies against selected proteins were encapsulated in 0.7 mm alginate polylysine microcapsules. The capsule membrane permeability to IgG (150 kDa), Transferrin (81 kDa), Tumor necrosis factor (TNF, 51 kDa), Interleukin-1 beta (IL-1 beta, 17.5 kDa), and insulin (5.8 kDa) was estimated by measuring the binding of 125I-labeled proteins to the encapsulated antibody coated Dynabeads. Capsules with an inhomogeneous solid gel core were made of alginates with high guluronic or high mannuronic acid content and poly-L (PLL)- or poly-D-lysine (PDL) of concentrations varied from 0.05-0.2%. The various capsules examined were all impermeable to IgG. The capsules made with a PLL-, but not PDL-membranes were permeable for transferrin. IL-1 beta was found to penetrate all of the different capsule types. The high-G capsules, however, could be made impermeable to TNF and still allowed transferrin to pass. The permeability of these capsules to IL-1 beta, but not to TNF was confirmed in an assay where mouse islets of Langerhans were incubated with TNF and IL-1 beta, and comparing the IL-6 for encapsulated and non-encapsulated islets.

Assessment of insulin secretion in vitro from microencapsulated fetal porcine islet-like cell clusters and rat, mouse, and human pancreatic islets.

BACKGROUND: The possibility of transplanting microencapsulated pancreatic islets into patients with insulin-dependent diabetes mellitus, either as allografts or xenografts, has attracted great interest. A critical evaluation of the results obtained reveals that the success has been very limited. The aim of the present study was to compare the in vitro function of microencapsulated islets obtained from adult humans, adult mice, adult rats, and fetal pigs. METHODS: Human pancreatic islets were isolated at beta-Cell Transplant in Brussels, Belgium, and sent to the Department of Medical Cell Biology, Uppsala University in Uppsala, Sweden. Rat and mouse pancreatic islets and fetal porcine islet-like cell clusters (ICC) were prepared in Uppsala. All groups of islets were subsequently sent to the Department of Biotechnology, Norwegian Institute of Biotechnology, University of Trondheim, Trondheim, Norway. After 1 day in tissue culture, the islets were microencapsulated in alginate then cultured and sent back to Uppsala the next day. After either overnight culture (day 1) or 6 days of culture (day 6), the microencapsulated islets were examined for their insulin content and insulin release. Nonencapsulated islets from the same isolations were used as controls. RESULTS: The insulin content of rodent and human islets was not affected by microencapsulation, whereas porcine ICC showed a diminished insulin content. Microencapsulated porcine ICC also had a marked reduction in their insulin secretion in response to stimulation with glucose or glucose + theophylline both on days 1 and 6 in tissue culture. Mouse islets showed a reduced insulin response at both time points. Rat islets exhibited an inhibition of insulin secretion on day 1, but this had been restored by day 6. Human islets had well-preserved insulin secretion after both days 1 and 6. Microencapsulated human islets showed a normal morphology 3-4 weeks after intraperitoneal transplantation to nude mice. CONCLUSIONS: Pancreatic islets isolated from human, rat, and mouse donors show a glucose-stimulated insulin release in vitro after microencapsulation and repeated transports between laboratories. The insulin secretory capacity of microencapsulated human and rat islets was preserved best, whereas mouse islets and particularly fetal porcine ICC were impaired by microencapsulation.

Alginate polycation microcapsules. II. Some functional properties.

The main cause of alginate polycation capsule breakage under physiological conditions is probably the osmotic swelling of the alginate core owing to the Donnan equilibrium set up by the negative charges of the carboxyl groups not involved in cooperative binding of counterions in the junction zones of the network. In the present paper we show how capsules can be stabilized extensively by reducing their swelling capacity in various ways. Alginate polycation capsules with good chemical and mechanical stability have been made by controlling their swelling behaviour through selection of capsule material according to chemical structure and molecular weight, as well as by controlling the kinetics of the capsule formation. Stable capsules have been made either by increasing the strength of the polyanion-polycation membrane, or by keeping a low-swelling gel network in the core. The latter capsules are made from an alginate rich in guluronic acid both in the core and in an outer coating, and with anisotropic distribution of the polymer material in the core where the concentration at the surface is higher than that in the centre of the capsule. Some functional properties of these capsules, such as porosity, have also been studied.

Alginate polycation microcapsules. I. Interaction between alginate and polycation.

The interactions between alginate and polycations have been studied by using different labelling techniques. Binding of poly-L-lysine (PLL) to alginate in the gel state is mainly governed by the amount of dissociable negative charges on the bead surface. PLL was found to bind more rapidly to gel beads made from alginate with a high content of mannuronic acid. The binding was enhanced by increasing the alginate concentration on the surface by making inhomogeneous beads. When the capsules were stored in the presence of cations with high affinity for alginate (Ca2+, Sr2+), PLL was washed off. Less PLL is bound to strontium alginate than to calcium alginate beads. Two mechanisms appear to be responsible for the binding of sodium alginate to alginate PLL capsules (coating): (i) an electrostatic interaction between the soluble coating material and excess positive charges on PLL on the surface; (ii) the formation of a calcium alginate gel on the surface owing to leaching of calcium ions from the core. The stability and efficiency of the coating as a function of molecular size and sequential structure of the coating polymer have also been investigated.