Evaluating the antimicrobial efficacy of long-lasting hand sanitizers on skin

BACKGROUND

The microbicidal efficacy of hand sanitizer formulations is usually measured through standardized quantitative suspension tests and fingerpad tests; these cannot evaluate long-lasting formulations or are impractical due to biological risks, high cost, or time required for testing. With increased numbers of long-lasting microbicidal activity claims of commercially available hand sanitizers, alternative testing strategies are required.

AIM

To explore the use of a standardized ex-vivo pig skin model to reproducibly measure long-lasting efficacy of an alcohol-free hand sanitizer formulation.

METHODS

The microbicidal efficacy of an alcohol-free hand sanitizer was tested against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae, and the enveloped virus SARS-CoV-2 with quantitative suspension tests (EN13727 and EN14476) with a contact time of 5 min. The product was then tested over a 6 h period using an ex-vivo pig skin model with a modified version of PAS 2424 to simulate the impact of skin abrasion.

FINDINGS

Quantitative suspension tests yielded a >5 log10 reduction for all organisms tested within a 5 min contact time. Pig skin tests showed reduced but consistent efficacy at all time points and indicated no significant impact of abrasion on efficacy.

CONCLUSION

The use of the ex-vivo pig skin model provides a potentially viable and convenient model system to test long-lasting hand sanitizer formulations, providing a path for sustainable hand sanitizer formulation claims of activity on skin.

What are the characteristics of participatory surveillance systems for influenza-like-illness?

Background

Seasonal influenza causes significant morbidity and mortality, with an estimated 9.4 million hospitalisations and 290 000-650 000 respiratory related-deaths globally each year. Influenza can also cause mild illness, which is why not all symptomatic persons might necessarily be tested for influenza. To monitor influenza activity, healthcare facility-based syndromic surveillance for influenza-like illness is often implemented. Participatory surveillance systems for influenza-like illness (ILI) play an important role in influenza surveillance and can complement traditional facility-based surveillance systems to provide real-time estimates of influenza-like illness activity. However, such systems differ in designs between countries and contexts, making it necessary to identify their characteristics to better understand how they fit traditional surveillance systems. Consequently, we aimed to investigate the performance of participatory surveillance systems for ILI worldwide.

Methods

We systematically searched four databases for relevant articles on influenza participatory surveillance systems for ILI. We extracted data from the included, eligible studies and assessed their quality using the Joanna Briggs Critical Appraisal Tools. We then synthesised the findings using narrative synthesis.

Results

We included 39 out of 3797 retrieved articles for analysis. We identified 26 participatory surveillance systems, most of which sought to capture the burden and trends of influenza-like illness and acute respiratory infections among cohorts with risk factors for influenza-like illness. Of all the surveillance system attributes assessed, 52% reported on correlation with other surveillance systems, 27% on representativeness, and 21% on acceptability. Among studies that reported these attributes, all systems were rated highly in terms of simplicity, flexibility, sensitivity, utility, and timeliness. Most systems (87.5%) were also well accepted by users, though participation rates varied widely. However, despite their potential for greater reach and accessibility, most systems (90%) fared poorly in terms of representativeness of the population. Stability was a concern for some systems (60%), as was completeness (50%).

Conclusions

The analysis of participatory surveillance system attributes showed their potential in providing timely and reliable influenza data, especially in combination with traditional hospital- and laboratory led-surveillance systems. Further research is needed to design future systems with greater uptake and utility.

Variations in breast cancer histology and treatment patterns between the major ethnic groups of South West Sydney

Studies in the United States and United Kingdom have demonstrated ethnic variations in breast cancer receptor status, histology, and treatment access. This study aimed to investigate whether ethnicity variation similarly exists in Australia. Patients diagnosed with breast cancer between 2006 and 2011 across all public hospitals in the South Western Sydney Local Health District were identified and patient data collected retrospectively. Logistic regression analysis was used to measure the association between various biologic and treatment parameters and ethnicity. Ethnicity was found to have an influence on age of diagnosis, histology, treatment utilization, and recurrence in breast cancer patients.

Relative efficacies of omega-3 polyunsaturated fatty acids in reducing expression of key proteins in a model system for studying osteoarthritis

OBJECTIVE

To assess the relative efficacy of three different omega-3 (n-3) polyunsaturated fatty acids (PUFAs) in suppressing the mRNA levels for important proteins involved in the etiology of osteoarthritis (OA).

METHODS

A model cell culture system (bovine chondrocytes) was used. Inflammatory factors and enzymes involved in OA were induced by exposure of the chondrocyte cultures to interleukin-1alpha (IL-1alpha). The effect of pre-incubating cultures with various amounts of exogenous fatty acids on subsequent levels of mRNAs was assessed by reverse transcription-polymerase chain reactions (RT-PCR).

RESULTS

Exposure of cultures to IL-1alpha induced expression of the cartilage proteinases A Disintegrin And Metalloproteinase with ThromboSpondin motifs (ADAMTS)-4 and ADAMTS-5, cyclooxygenase (COX)-2, the matrix metalloproteinase (MMP)-3 and the inflammatory cytokines IL-1alpha, interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha). n-3 PUFAs were able to reduce the levels of mRNA for ADAMTS-4, ADAMTS-5, MMP-3, MMP-13, COX-2 (but not COX-1), IL-1alpha, IL-1beta and TNF-alpha. Eicosapentaenoic acid (EPA) was the most effective, followed by docosahexaenoic (DHA) and then alpha-linolenic (ALA) acid. The n-6 PUFA, arachidonic acid (AA) had no effect.

CONCLUSION

These results show that omega-3 (n-3) PUFAs cause a reduction in the mRNA levels for various proteins known to be important in the pathology of OA. They provide a molecular explanation, at least in part, for beneficial effects of dietary omega-3 PUFAs for the amelioration of symptoms of the disease. The relative efficacy of EPA suggests that this omega-3 PUFA may be especially useful for dietary supplementation in patients with OA.

The platelet angiotensin II receptor in type I diabetes: studies in patients with and without nephropathy

Experimental studies demonstrate impaired regulation of the mesangial angiotensin II (AII) receptor in diabetes. This could contribute to the disturbance of glomerular blood flow and the development of diabetic nephropathy. The aim of this study was to determine whether a similar receptor abnormality occurs in patients with type I insulin-dependent diabetes mellitus (IDDM) and if so whether this is more prevalent in patients with micro- or macro-albuminuria. The platelet AII receptor was chosen because of its availability from the circulation and its comparable regulatory properties to tissue-based receptors. The interaction between plasma AII and its platelet receptor was examined in 45 patients with IDDM and 36 age- and sex-matched control subjects. Seven patients had clinical nephropathy and two had persistent micro-albuminuria. The duration of diabetes varied from 1 month to 42 years. There was a significant inverse correlation between plasma AII and the logarithm of receptor number in the control group (r = -0.555, P < 0.001). This relationship was not observed in the diabetic patients irrespective of the duration of disease or the presence of nephropathy. Receptor expression in patients without nephropathy showed no correlation with either duration of disease or the degree of glycaemic control. However, a significant relationship between AII receptor number and duration of diabetes was noted in the group with nephropathy (r = 0.723, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormality of the glomerular angiotensin II receptor in experimental diabetic nephropathy

1. The combined effect of diabetes and hypertension on the plasma angiotensin II (AII)/glomerular AII receptor (AII-R) relationship in streptozotocin-induced diabetes was investigated as well as the effect of glycaemic control on this relationship. 2. Diabetes was induced in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats with streptozotocin 60 mg/kg and blood sugars maintained between 18-21 mmol/L (uncontrolled diabetes) and 4-8 mmol/L (controlled diabetes). Rats were killed on days 1 and 7. Angiotensin II receptor was estimated by saturation analysis and plasma AII by radio-immunoassay. 3. Angiotensin II receptors were significantly higher in non-diabetic SHR than WKY rats (708 +/- 62 and 388 +/- 36 fmol/mg protein, respectively, P = 0.0008). Plasma AII were comparable in both groups (47 +/- 2.7, 38 +/- 3.5 pg/mL, respectively) and a significant inverse relationship between AII/AII-R was observed (WKY P = 0.02 and SHR P = 0.004). 4. On day 7, plasma AII and AII-R levels in diabetic groups were comparable with those of their non-diabetic controls. Diabetic WKY rats maintained an inverse correlation between AII and AII-R (controlled P = 0.04 and uncontrolled P = 0.015), but this did not occur in the SHR. 5. Absence of receptor response to varying ligand concentrations in the diabetic SHR may contribute to the development of nephropathy. Glycaemic control does not appear to reverse this abnormality in the SHR, so that co-existent hypertension may have a more direct influence on renal function.

Uridine kinase inhibition is involved in the vasodilator effects of minoxidil in the rat

1. Since minoxidil is a pyrimidine derivative, its actions on vascular smooth muscle may derive from structural relationships to the uridine nucleotides, which have been shown to be vasoconstrictive in the rat. 2. Minoxidil at a low vasodepressor dose of 0.03 mg/kg per min abolished the pressor response to uridine at doses from 2 to 8 mumol/kg per min, but did not reduce the responses to uridine monophosphate or uridine diphosphate in similar pressor doses, suggesting an action on either transport of uridine into cells or on uridine kinase which catalyses phosphorylation of uridine to uridine monophosphate, the mediator of uridine's vascular actions. 3. The active metabolite of minoxidil was found to inhibit rat liver uridine kinase in vivo using an HPLC technique. 4. Plasma uridine concentration was significantly higher in 11 hypertensive patients on minoxidil compared with pretreatment values, suggesting that uridine kinase inhibition is of a degree sufficient to increase the circulating pool of uridine. 5. The data is consistent with uridine kinase inhibition being a mechanism for the vasodilator actions of minoxidil.

Integrins isolated from Rous sarcoma virus-transformed chicken embryo fibroblasts

Avian integrins are a complex of three integral membrane glycoproteins that are thought to have a role both in anchoring the cytoskeleton to the plasma membrane and establishing linkages to the extracellular matrix. We previously demonstrated that bands 2 and 3 of integrin are phosphorylated on both tyrosine and serine residues in chicken embryo fibroblasts (CEF) transformed with Rous Sarcoma virus (RSV) and other oncogenic retroviruses. The effects of RSV transformation on integrins from chick cells are now further characterized. The major site of tyrosine phosphorylation on band 3 in RSV transformed CEF has been identified as tyrosine 788. We also demonstrate that the product of the RSV oncogene, pp60v-src, can phosphorylate integrin in vitro, at the same residue. Tryptic peptide mapping and tunicamycin treatment indicates that a previously observed 4-8 k increase in the Mr of integrins from RSV-transformed cells can be attributed to an alteration in a post-translational modification such as glycosylation. Equilibrium gel filtration assays were used to test the ability of integrins from RSV-transformed CEF to interact with talin and fibronectin. Tyrosine phosphorylated integrins showed a decreased ability to interact with both these ligands in vitro. Conversely, integrins isolated from RSV-transformed CEF metabolically labeled in the absence of phosphatase inhibitor contained only low levels of phosphotyrosine and showed an almost normal ability to interact with ligands. Competition experiments indicated that the region of integrin containing tyrosine 788 is also important for talin binding to integrins.

Effect of alcohol content on beer consumption by rats

Three brands of beer of varying alcohol content were presented to separate groups of male rats. The consumption data indicated, firstly, an inverse relationship between acceptability of the beer and its alcohol content. The data also indicated that the acceptability of full-strength beer could be augmented by prior exposure to low-alcohol and alcohol-free beer. The results are discussed with reference to orosensory- and inebriation-based models of alcohol consumption.

Integrin (the CSAT antigen): functionality requires oligomeric integrity

Integrin, the cell-substrate attachment (CSAT) antigen, is a complex of integral membrane glycoproteins whose apparent function is to mediate cell-substratum adhesion by serving as a transmembrane link between the extracellular matrix and elements of the cytoskeleton. Previous attempts to separate the members of this complex under nondenaturing conditions have been successful. We have now produced a monoclonal antibody "G" that is specific for the lower molecular mass cysteine-rich band 3 of the complex. Using an antibody affinity column containing this monoclonal antibody, it is possible to dissociate integrin into two fractions, one containing band 3, the other containing bands 1 plus 2. Neither fraction will by itself bind fibronectin, laminin, or talin. However, when the fractions are combined, the reconstituted integrin elutes from a gel filtration column in the same position as the native complex, and binding activity to these molecules returns. Further, it is shown by gel filtration that the recognition site for the adhesion-disrupting monoclonal antibodies CSAT and JG22 is on band 3, supporting the contention that integrin is an oligomer. The data presented here is consistent with integrin being either a mixture of heterodimers, each with a common subunit and reacting with a particular extracellular matrix molecule, or a single heterotrimer capable of binding to several different extracellular matrix molecules.

Interaction of plasma membrane fibronectin receptor with talin--a transmembrane linkage

Many observations suggest the presence of transmembrane linkages between the cytoskeleton and the extracellular matrix. In fibroblasts both light and electron microscopic observations reveal a co-alignment between actin filaments at the cell surface and extracellular fibronectin. These associations are seen at sites of cell matrix interaction, frequently along stress fibres and sometimes where these bundles of microfilaments terminate at adhesion plaques (focal contacts). Non-morphological evidence also indicates a functional linkage between the cytoskeleton and extracellular matrix. Addition of fibronectin to transformed cells induces flattening of the cells and a reorganization of the actin cytoskeleton, with the concomitant appearance of arrays of stress fibres. Conversely, disruption of the actin cytoskeleton by treatment with cytochalasin B leads to release of fibronectin from the cell surface. As yet, there is no detailed knowledge of the molecules involved in this transmembrane linkage, although several proteins have been suggested as candidates in the chain of attachment between bundles of actin filaments and the cytoplasmic face of the plasma membrane: these include vinculin, alpha-actinin and talin, each one having been identified at regions where bundles of actin filaments interact with the plasma membrane and underlying cell-surface fibronectin. Recently, the cell-substrate attachment (CSAT) antigen has been identified as a plasma membrane receptor for fibronectin, raising the possibility that this glycoprotein complex may serve as a bridge between fibronectin and one or more of the underlying cytoskeletal components mentioned. Here we have investigated the interaction of the purified CSAT antigen with these cytoskeletal components, and we demonstrate an interaction specifically between the CSAT antigen and talin.

The cell substrate attachment (CSAT) antigen has properties of a receptor for laminin and fibronectin

The cell substrate attachment (CSAT) antigen is an integral membrane glycoprotein complex that participates in the adhesion of cells to extracellular molecules. The CSAT monoclonal antibody, directed against this complex, inhibited adhesion of cardiac and tendon fibroblasts and skeletal myoblasts to both laminin and fibronectin, thus implicating the CSAT antigen in adhesion to these extracellular molecules. Equilibrium gel filtration was used to explore the hypothesis that the CSAT antigen functions as a cell surface receptor for both laminin and fibronectin. In this technique, designed for rapidly exchanging equilibria, the gel filtration column is pre-equilibrated with extracellular ligand to ensure receptor occupancy during its journey through the column. Both laminin and fibronectin formed complexes with the CSAT antigen. The association with laminin was inhibited by the CSAT monoclonal antibody; the associations with both fibronectin and laminin were inhibited by synthetic peptides containing the fibronectin cell-binding sequence. Estimates of the dissociation constants by equilibrium gel filtration agree well with those available from other measurements. This suggests that these associations are biologically significant. SDS PAGE showed that all three glycoproteins comprising the CSAT antigen were present in the antigen-ligand complexes. Gel filtration and velocity sedimentation were used to show that the three bands comprise and oligomeric complex, which provides an explanation for their functional association. The inhibition of adhesion by the CSAT monoclonal antibody and the association of the purified antigen with extracellular ligands are interpreted as strongly implicating the CSAT antigen as a receptor for both fibronectin and laminin and perhaps for other extracellular molecules as well.

Adhesive multiplicity in the interaction of embryonic fibroblasts and myoblasts with extracellular matrices

Neff et al. (1982, J. Cell Biol., 95:654-666) have described a monoclonal antibody, CSAT, directed against a cell surface antigen that participates in the adhesion of skeletal muscle to extracellular matrices. We used the same antibody to compare and parse the determinants of adhesion and morphology on myogenic and fibrogenic cells. We report here that the antigen is present on skeletal and cardiac muscle and on tendon, skeletal, dermal, and cardiac fibroblasts; however, its contribution to their morphology and adhesion is different. The antibody produces large alterations in the morphology and adhesion of skeletal myoblasts and tendon fibroblasts; in contrast, its effects on the cardiac fibroblasts are not readily detected. The effects of CSAT on the other cell types, i.e., dermal and skeletal fibroblasts, cardiac muscle, 5-bromodeoxyuridine-treated skeletal muscle, lie between these extremes. The effects of CSAT on the skeletal myoblasts depends on the calcium concentration in the growth medium and on the culture age. We interpret these differential responses to CSAT as revealing differences in the adhesion of the various cells to extracellular matrices. This interpretation is supported by parallel studies using quantitative assays of cell-matrix adhesion. The likely origin of these adhesive differences is the progressive display of different kinds of adhesion-related molecules and their organizational complexes on increasingly adhesive cells. The antigen to which CSAT is directed is present on all of the above cells and thus appears to be a lowest common denominator of their adhesion to extracellular matrices.