Antibacterial and antifungal potential of Ga-bioactive glass and Ga-bioactive glass/polymeric hydrogel composites.

A bioactive glass series (0.42SiO2 -0.10Na2 O-0.08CaO-(0.40 - x)ZnO-(x)Ga2 O3 ) was synthesized, and it is efficacy against the Gram (-ve) bacteria Escherichia coli (E. coli), the Gram (+ve) bacteria Staphylococcus aureus (S. aureus), and the fungus Candida albicans (C. albicans), were characterized through liquid broth analysis. The glass series was also seeded in CMC-Dex hydrogels at three different loadings (0.05, 0.10, and 0.25 m2 ), and the antibacterial and antifungal efficacies of the resulting composites were characterized using both liquid broth and agar diffusion analysis. Liquid broth analysis was conducted using liquid extracts, which for glass samples were obtained after incubation for up to 30 days in both ultrapure water and phosphate buffered saline (PBS), while glass-hydrogel extracts were obtained solely in PBS. Glass extracts (water) decreased C. albicans viability, while those obtained in PBS decreased the viability of both E. coli and C. albicans. Glass-hydrogel extracts exhibited slight inhibition of E. coli and C. albicans. However, none of the liquid extracts decreased S. aureus viability. Glass-hydrogel composites produced inhibition zones in all three microbial cultures, with the greatest efficacy against C. albicans. The results of this study suggest these materials have potential as bone void-filling materials which display antifungal, and possibly, antibacterial properties. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1102-1113, 2017.

Structural characterization and anti-cancerous potential of gallium bioactive glass/hydrogel composites.

A bioactive glass series (0.42SiO2-0.10Na2O-0.08CaO-(0.40-X)ZnO-(X)Ga2O3) was incorporated into carboxymethyl cellulose (CMC)/dextran (Dex) hydrogels in three different amounts (0.05, 0.10, and 0.25m(2)), and the resulting composites were characterized using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and (13)C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (CP MAS-NMR). Composite extracts were also evaluated in vitro against MG-63 osteosarcoma cells. TEM confirmed glass distribution throughout the composites, although some particle agglomeration was observed. DSC revealed that glass composition and content did have small effects on both Tg and Tm. MAS-NMR revealed that both CMC and Dex were successfully functionalized, that cross-linking occurred, and that glass addition did slightly alter bonding environments. Cell viability analysis suggested that extracts of the glass and composites with the largest Ga-content significantly decreased MG-63 osteosarcoma viability after 30days. This study successfully characterized this composite series, and demonstrated their potential for anti-cancerous applications.

Synthesis, characterization, and in vitro cytocompatibility of Ga-bioactive glass/polymer hydrogel composites.

A bioactive glass series (0.42SiO2-0.10Na2O-0.08CaO-(0.40-x)ZnO-(x)Ga2O3) was incorporated in carboxymethyl cellulose-dextran hydrogels at three different loadings (0.05, 0.10, and 0.25 m2), and the resulting composites were characterized using scanning electron microscopy, physical swelling characteristics, and inductively coupled plasma optical emission spectroscopy. In vitro cytocompatibility was also evaluated for composite extracts in contact with L-929 mouse fibroblasts and MC3T3-E1 human osteoblasts. Scanning electron microscopy confirmed that glass particles were distributed throughout the hydrogels, and swelling studies showed that glass presence can increase the amount of fluid that can be absorbed by the hydrogels after seven days of immersion in phosphate-buffered saline by up to 180%. Several trends were observed in the inductively coupled plasma optical emission spectroscopy data, with the most important being the release of Ga3+ from both Ga-containing glasses at all three loadings, with a maximum of 4.7 mg/L released after 30 days of incubation in phosphate-buffered saline. Cell viability analysis suggested that most composite extracts did not decrease neither fibroblast nor osteoblast viability. These results indicate that it is possible to embed bioactive glass particles into carboxymethyl cellulose-dextran hydrogels, and upon submersion in aqueous media, release ions from the glass particles that may elicit therapeutic effects.

Investigating the effect of silver coating on the solubility, antibacterial properties, and cytocompatibility of glass microspheres.

Silver (Ag) coatings have been incorporated into many medical materials due to its ability to eradicate harmful microbes. In this study, glass microspheres (SiO2-Na2O-CaO-Al2O3) were synthesized and employed as substrates to investigate the effect Ag coating has on glass solubility and the subsequent biological effects. Initially, glasses were amorphous with a glass transition point (T(g)) of 605℃ and microspheres were spherical with a mean particle diameter of 120 µm (±27). The Ag coating was determined to be crystalline in nature and its presence was confirmed using scanning electron microscopy and X-ray photoelectron spectroscopy. Ion release determined that Ag-coated (Ag-S) microspheres increased the Na(+) release rate but slightly reduced the Ca(2+) and Si(4+) release compared to an uncoated control (UC-S). Additionally, the Ag-S reduced the pH to just above neutral (7.3-8.5) compared to the UC-S (7.7-9.1). Antibacterial testing determined significant reductions in planktonic Escherichia coli (p = 0.000), Staphylococcus epidermidis (p = 0.000) and Staphylococcus aureus (p = 0.000) growth as a function of the presence of Ag and with respect to maturation (1, 7, and 30 days). Testing for toxicity levels using L929 Fibroblasts determined higher cell viability for the Ag-S at lower concentrations (5 µg/ml); in addition, no significant reduction in cell viability was observed with higher concentrations (15, 30 µg/ml).

Comparison of a SiO2-CaO-ZnO-SrO glass polyalkenoate cement to commercial dental materials: ion release, biocompatibility and antibacterial properties.

Ion Release and biocompatibility of a CaO-SrO-ZnO-SiO2 (BT 101) based glass polyalkenoate cement (GPC) was compared against commercial GPCs, Fuji IX and Ketac Molar. The radiopacity (R) was similar for each material, 2.0-2.8. Ion release was evaluated on each material over 1, 7, 30 and 90 days. BT 101 release included Ca (23 mg/L), Sr (23 mg/L) Zn (13 mg/L), Si (203 mg/L). Fuji IX release includes Ca (0.7 mg/L), Al (3 mg/L) Si (26 mg/L), Na (60 mg/L) and P (0.5 mg/L) while Ketac Molar release includes Ca (1 mg/L), Al (0.6 mg/L) Si (23 mg/L), Na (76 mg/L) and P (0.7 mg/L). Simulated body fluid trials revealed CaP surface precipitation on BT 101. No evidence of precipitation was found on Fuji IX or Ketac Molar. Cytotoxicity testing found similar cell viability values for each material (~60 %, P = 1.000). Antibacterial testing determined a reduced CFU count with BT 101 (2.5 × 10³) when compared to the control bacteria (2.4 × 104), Fuji IX (1.5 × 104) and Ketac Molar (1.2 × 104).

Does elevating silver content in zinc-based glass polyalkenoate cements increase their antibacterial efficacy against two common bacteria using the agar gel diffusion method?

The authors have previously shown that it is possible to incorporate silver into a soda-zinc-silicate glass and subsequently form a glass polyalkenoate cement from it. The objective of the research described herein is to determine if incremental increases in the silver content of these glass polyalkenoate cements will increase their antibacterial efficacy against gram-positive and gram-negative bacteria using the accepted spread plate method. Four glass polyalkenoate cements were formulated; three contained increasing amounts of silver incorporated into them (cements A, B, and C, containing 0.33 mol%, 0.66 mol%, and 0.99 mol% silver, respectively) and a fourth contained no silver, which acted as a control (control cement). The handling properties of the glass polyalkenoate cements were evaluated, where working times were around 2 min and setting times ranged from 1 h 17 min to 2 h 41 min. Inductively coupled plasma atomic emission spectroscopy was employed to determine silver ion release with cement maturation for up to 14 days. The majority of silver ions were released within the first 24 h, with up to 2 mg/L cumulative ion release recorded up to 14 days. The antibacterial properties of the coatings were evaluated against Staphylococcus aureus and Pseudomonas aeruginosa bacteria. The silver-glass polyalkenoate cements exhibited antibacterial effect against both bacterial strains. The maximum inhibition zones recorded against S. aureus was 14.8 mm (SD ± 1.11) and against P. aeruginosa was 20.6 mm (SD ± 0.81). Cement B had a greater antibacterial effect compared to cement A, however, cements B and C had comparable antibacterial effects after 14 days even though cement C contained 0.33 mol% more silver than B. This indicates that by increasing the silver content in these cements, the antibacterial efficacy increases to a point, but there is a threshold where further silver ion release does not increase the antibacterial effect.

Regression model for predicting selected thermal properties of next-generation bioactive glasses.

The compositional palette traditionally used to develop bioactive glasses has grown in recent times to include therapeutic inorganic species such as zinc and strontium. Historical regression models used for predicting the properties of bioactive glasses as a function of composition have not evolved to consider this expanded compositional space. In this work, nonlinear regression analysis was applied to historical data to construct predictive models for the glass transition temperature and the coefficient of thermal expansion of next-generation bioactive glasses. The new regression models also provide some degree of improvement over existing models in predicting the properties of traditional bioactive glasses.

Antitumor efficacy of AAV-mediated systemic delivery of interferon-beta.

Type I interferons (alpha/beta) have significant antitumor activity although their short half-life and systemic side effects have limited their clinical utility. An alternative dosing schedule of continuous, low-level delivery, as is achieved by gene therapy, rather than intermittent, high concentration pulsed-dosing, might avoid the toxicity of interferon while maintaining its antitumor efficacy. We have tested a gene therapy approach in murine tumor models to treat malignancies that have shown responsiveness to interferon in clinical trials. The tumor cell lines used were moderately sensitive to the direct effects of human interferon-beta (hIFN-beta) in vitro. For in vivo testing, systemic delivery of hIFN-beta was generated following liver-targeted delivery of adeno-associated virus (AAV) vector carrying the hIFN-beta transgene. This prevented engraftment of subcutaneous human gliomas, and orthotopic, localized (intrarenal) and disseminated (primarily pulmonary) human renal cell carcinomas; and caused regression of established tumors at these sites. In a syngeneic, immunocompetent model of melanoma, AAV IFN-beta treatment limited subcutaneous tumor growth and prevented disseminated disease. A significant decrease in mean intratumoral vessel density was demonstrated in hIFN-beta-treated tumors, suggesting that in addition to a direct tumoricidal effect, the antitumor efficacy of AAV IFN-beta in this study was due to its ability to inhibit angiogenesis.

Effect of glass dissolution products on the detection of proteins by silver staining.

The influence of glass dissolution on the silver staining of proteins was investigated by reacting glass microspheres of varying chemical durability in boiling Laemmli sample buffer (LSB) for up to 5 min. All three of the investigated glass compositions leached Na+ ions to varying degrees during boiling in LSB, thereby causing an increase in the pH of the sample buffer. The LSB supernatant from the dissolution tests was mixed with unreacted LSB containing human serum albumin (HSA) and standard one-dimensional SDS-PAGE was performed. Silver staining was then used to visualize protein bands within the gel. The 30 Na2O.70 SiO2 glass exhibited pronounced degradation as shown by scanning electron microscopy. Further experiments employing solutions of neat LSB and reacted LSB (i.e., LSB containing glass dissolution products) mixed at varying ratios demonstrated the apparent significance of sample pH in affecting the inhibition of silver staining. The cause of this behavior may be due to an interference with the fixation stage of the staining protocol, thereby resulting in the loss of protein in subsequent rinsing stages.

In vitro bioactivity of S520 glass fibers and initial assessment of osteoblast attachment.

Bioactive glass fibers are attractive materials for use as tissue-engineering scaffolds and as the reinforcing phase for resorbable bioactive composites. The bioactivity of S520 glass fibers (52.0 mol % SiO(2), 20.9 Na(2)O, 7.1 K(2)O, 18.0 CaO, and 2.0 P(2)O(5)) was evaluated in two media, simulated body fluid (SBF) and Dulbecco's modified Eagle's medium (DMEM), for up to 20 days at 37 degrees C. Hydroxyapatite formation was observed on S520 fiber surfaces after 5 h in SBF. After a 20-day immersion, a continuous hydroxyapatite layer was present on the surface of samples immersed in SBF as well as on those samples immersed in DMEM [fiber surface area to solution volume ratio (SA:V) of 0.10 cm(2)/mL]. Backscattered electron imaging and EDS analysis revealed that the hydroxyapatite layer formation was more extensive for samples immersed in SBF. Decreasing the SA:V ratio to 0.05 cm(2)/mL decreased the time required to form a continuous hydroxyapatite surface layer. ICP was used to reveal Si, Ca, and P release profiles in DMEM after the 1st h (15.1, 83.8, and 29.7 ppm, respectively) were similar to those concentrations previously determined to stimulate gene expression in osteoblasts in vitro (16.5, 83.3, and 30.4 ppm, respectively). The tensile strength of the 20-microm diameter fibers was 925 +/- 424 MPa. Primary human osteoblast attachment to the fiber surface was studied by using SEM, and mineralization was studied by using alizarin red staining. Osteoblast dorsal ruffles, cell projections, and lamellipodia were observed, and by 7 days, cells had proliferated to form monolayer areas as shown by SEM. At 14 days, nodule formation was observed, and these nodules stained positive for alizarin red, demonstrating Ca deposition and, therefore mineralization.

Breaking the silence: marginalisation of registered nurses employed in nursing homes.

This paper reports on a study which employed auto/biography as a research method to expose the marginalisation and discrimination experienced by Registered Nurses (RN) employed in the nursing home sector. By virtue of their area of practice, these nurses are frequently perceived by the wider nursing community and society at large to be deskilled and not competent. A critical incident from my story is recounted and thereafter discussed from a personal perspective and within a wider context of nursing and related literature. I argue that the complexity of clinical practice in a nursing home means that RNs are no less skilled or competent than RNs in other clinical settings. However, marginalisation and discrimination occur because nurses and nursing are not isolated from the values and beliefs of society. This is a society which under values caring and nurturing and places a higher value on complex technologies with an emphasis on cure being the dominant ideology. The style of reporting the research is congruent with an auto/biographical approach.

Process control procedures to augment quality control of leukocyte-reduced red cell blood products.

Quality control of leukocyte-reduced packed red cell units (LRprc) produced in blood facilities must conform to regulatory criteria, which state that units may not contain more than 1 x 10(6) to 5 x 10(6) white blood cells (WBC) per unit. The post-filtration WBC content of a total of n = 386 LRprc units was counted with a Nageotte chamber to model the probability that a unit would not meet the regulatory criteria. The distribution of the residual leukocyte counts is close to a negative binomial distribution (NBD) and is independent of the packed red cell volume filtered. The observed probability that a unit of blood has a residual WBC greater than 5 x 10(6) is 2.6 +/- 2.6 x 10(-3). A power analysis of the two-sample Kolmogorov-Smirnov (KS) test in this application shows that a sample size of 20 is sufficient for determining that the process is in control when an out of control process has a k NBD parameter greater than or equal to that of the in control process. The three out of control processes observed to date appear to have this property. A sample of size 80 may be necessary for confirming that process validation data sets conform to the larger 'reference' database (n = 386) for processes that are out of control in such a way that their k NBD parameter is less than the k parameter of the in control process.

Efficacy and safety of transurethral alprostadil therapy in men with erectile dysfunction. MUSE Study Group.

OBJECTIVE: To examine the safety and efficacy of transurethral pharmacotherapy for erectile dysfunction, involving the use of a novel therapeutic system to administer alprostadil (prostaglandin E1) to the urethral mucosa in a double-blind, randomized, parallel, placebo-controlled study conducted in five countries in Europe. PATIENTS AND METHODS: In an outpatient setting, patients with primarily organic erectile dysfunction of at least 3 months' duration were treated with transurethral alprostadil, in an open-label, dose-escalating study. Testing stopped when the dose provided an erection sufficient for intercourse, as assessed by the patient and the investigator. Patients who achieved a sufficient response were then randomized to either active medication at the selected dose or to placebo for use at home for 3 months. After each home administration, patients recorded in diaries whether or not sexual intercourse occurred and any adverse reactions to the drug. RESULTS: A total of 249 patients were treated in an outpatient setting; of these patients, 159 (64%) achieved an erection sufficient for intercourse and were randomized (1:1) to either active medication or placebo for home treatment. Of the patients randomized to alprostadil for home treatment, 69% reported intercourse at least once, compared with 11% of patients randomized to placebo (P < 0.001). The most common adverse reaction, urethral pain/burning, was reported by 7% of patients in the clinic. Most patients (83%) graded transurethral alprostadil as causing minimal or no discomfort in the clinic. No patient reported priapism or developed penile fibrosis. CONCLUSION: Alprostadil delivered transurethrally by this system was well tolerated and effective in treating erectile dysfunction.

The effect of transurethral alprostadil on the quality of life of men with erectile dysfunction, and their partners. MUSE Study Group.

OBJECTIVE: To evaluate the impact of treatment for erectile dysfunction on the quality of life of men and their partners. PATIENTS AND METHODS: The study included 249 men with organic erectile dysfunction of more than 3 months' duration who self-administered transurethral alprostadil in an open-label, dose-escalating manner in an outpatient medical setting. Patients with a sufficient response (159) were randomly assigned in a double-blind protocol to either active medication or placebo for 3 months at home. Patients and partners each completed quality-of-life questionnaires before and after treatment. RESULTS: In the clinic 159 of the 249 men (64%) had an erection sufficient for intercourse when using transurethral alprostadil. At home, 46 of 67 men (69%) reported intercourse at least once on transurethral alprostadil, compared with eight of 73 (11%) on placebo (P < 0.001). Patients on alprostadil showed a 34% improvement in their 'relationship with partner', a 5% improvement in 'personal wellness', and a 71% improvement in 'quality of erection' domains, compared with a decline of 11%, 8% and 1%, respectively, in patients on placebo (P < 0.005 for each comparison). Partners of patients on alprostadil showed a 35% improvement in the 'relationship with partner' domain, compared with a 12% improvement in the placebo group (P = 0.028). There was a trend toward improvement in other partner domains. Urogenital pain was reported by 14% of patients during home treatment. CONCLUSION: The resumption of sexual intercourse with the use of transurethral alprostadil was accompanied by an improvement in several important quality-of-life domains in patients and their partners.

Low-frequency intensity noise in semiconductor lasers.

The low-frequency intensity noise at 25 MHz of a Fabry-Perot semiconductor laser is measured as a function of injection current. All the measurements are taken at room temperature and the laser is operated with a commercial current source (the conditions under which laser diodes are often used). At the highest injection current of twice threshold, the intensity noise is 5.5 dB above the shot-noise limit. When the longitudinal side mode suppression of the laser is 20 dB or larger, the intensity noise is modeled adequately by an expression derived from the single-mode, small-signal, linearized, semiclassical rate equations. All the parameters used in the theory are derived or referenced.

Molecular characterization of Salmonella enteritidis isolates from Maine poultry and poultry farm environments.

Eighty-six Salmonella enteritidis isolates obtained during a surveillance program of poultry farms in Maine were subjected to phage-typing, plasmid profiling and fingerprinting, outer-membrane polypeptide analysis, and antimicrobial sensitivity testing. Isolates were obtained from a variety of sources, including poultry-farm environmental samples, chicken organ samples, human stool samples, cat feces, and live-trapped rats and mice. These isolates were compared with 21 S. enteritidis isolates originating outside of Maine. Phage types isolated in Maine included 13a (60%); 14b (29%); 23 (5%); 8 (2%); and 2 (2%). All S. enteritidis isolates from Maine carried plasmid DNA, and 97% of these isolates carried a 40.3-megadalton plasmid alone (6%) or in conjunction with several smaller plasmids (91%). All 52 phage-type 13a isolates harbored 40.3- and 3.0-megadalton plasmids. All 25 phage-type 14b isolates carried 3.3- and 1.3-megadalton plasmids, and 22 isolates also carried the 40.3-megadalton plasmid. All isolates displayed highly similar outer-membrane polypeptide profiles and were sensitive to a variety of antimicrobials commonly used against gram-negative organisms. The above data suggest that phage type and plasmid content may be related in the cases of phage-type 13a and 14b isolates, and that traditional plasmid-borne antimicrobial resistance determinants were not present in Maine isolates. Results also indicate that phage-typing can be a valuable epizootiological tool for monitoring the potential spread of these strains throughout the Northeast.

Test-retest reliability of the Profile of Mood States using visually impaired athletes.

The test-retest reliabilities of the Profile of Mood States when items were read aloud on consecutive days to 15 nationally ranked visually impaired athletes ranged from .78 to .95, so the scale can be used with visually impaired athletes who cannot complete the profile in the traditional written manner.

Microbiologic analyses of nasal polyp tissue.

Nasal polyps from 40 patients were cultured within 2 1/2 hours after surgical removal to determine whether microorganisms were present. The first 20 polyps were cultured for aerobic and anaerobic bacteria, viruses, fungi, mycoplasmas, and mycobacteria. Of these 20 polyps, eight were sterile by all tests, one grew Cryptococcus albidus, one grew Sporobolomyces, one had large numbers of Peptostreptococcus micros and Propionibacterium acnes, greater than 10(6) colony-forming units per gram (cfu/gm), and nine had aerobic bacteria including 10 different species at levels less than 10(5) cfu/gm. The second 20 polyps were cultured for aerobic bacteria only; 11 polyps were positive. Overall, 14 of 26 polyps from patients with asthma and two of 14 polyps from patients without asthma were positive for aerobic bacteria at levels greater than 10(3) cfu/gm (p less than 0.05). Multiple aerobic bacterial species tended to occur in polyps from patients with asthma (11 of 26) more frequently than in those from patients without asthma (one of 14) (p less than 0.01). There was a highly significant positive correlation between tissue neutrophilia and bacterial count (r = +0.9; p less than 0.001). The results indicate that patients with asthma have a significantly higher number and a tendency to a greater variety of aerobic bacteria in nasal polyp tissue than patients without asthma and that the number of infiltrating neutrophils is directly related to the number of bacteria.