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Artificial urine for laboratory testing-revisited
... Bioluminescent MB49-Luc murine bladder cancer cells were kindly provided by Carla Molthoff (VU University Medical Center, The Netherlands) and cultured as described [15]. Synthetic urine consisting of 128 mM sodium chloride, 60 mM potassium chloride, 40 mM sodium phosphate, 303 mM urea, 50 µg/ml bovine serum albumin and 2 mg/ml creatinine, pH 6.0, was prepared as described [19]. ...
Background
Early detection and removal of bladder cancer in patients is crucial to prevent tumor recurrence and progression. Because current imaging techniques may fail to detect small lesions of in situ carcinomas, patients with bladder cancer often relapse after initial diagnosis, thereby requiring frequent follow-up and treatments.
Results
In an attempt to obtain a sensitive and high-resolution imaging modality for bladder cancer, we have developed a photoacoustic imaging approach based on the use of PEGylated gold nanorods (GNRs) as a contrast agent, functionalized with the peptide cyclic [CphgisoDGRG] (Iso4), a selective ligand of α5β1 integrin expressed by bladder cancer cells. This product (called GNRs@PEG-Iso4) was produced by a simple two-step procedure based on GNRs activation with lipoic acid-polyethyleneglycol(PEG-5KDa)-maleimide and functionalization with peptide Iso4. Biochemical and biological studies showed that GNRs@PEG-Iso4 can efficiently recognize purified integrin α5β1 and α5β1-positive bladder cancer cells. GNRs@PEG-Iso4 was stable and did not aggregate in urine or in 5% sodium chloride, or after freeze/thaw cycles or prolonged exposure to 55 °C, and, even more importantly, do not settle after instillation into the bladder. Intravesical instillation of GNRs@PEG-Iso4 into mice bearing orthotopic MB49-Luc bladder tumors, followed by photoacoustic imaging, efficiently detected small cancer lesions. The binding to tumor lesions was competed by a neutralizing anti-α5β1 integrin antibody; furthermore, no binding was observed to healthy bladders (α5β1-negative), pointing to a specific targeting mechanism.
Conclusion
GNRs@PEG-Iso4 represents a simple and robust contrast agent for photoacoustic imaging and diagnosis of small bladder cancer lesions.
Graphical Abstract
In this post-new-normal era, the public prioritizes preventive measures over curing, which is a constructive approach to staying healthy. In this study, an innovative antimicrobial membrane material has been developed, showcasing the promising potential for various applications. The metal-doped silica nanoparticles (Ag, Cu, and Co) were incorporated into a cellulose acetate (CA) polymer-based nanofiber membrane using the electrospinning technique. The metal nanoparticles were doped into a silanol network of silica nanoparticles. The fabricated membranes underwent detailed characterization using a wide range of techniques including PXRD, FTIR, Raman, SEM, TEM, TGA, and tensile testing. These analyses provided compelling evidence confirming the successful incorporation of metal-doped silica nanoparticles (Ag, Cu, and Co) into cellulose-based nanofibers. The band gap energies of the fabricated CA mats lie below 3.00 eV, confirming that they are visible light active. The trimetallic silica nanohybrid exhibited the lowest band gap energy of 2.84 eV, proving the self-sterilizing ability of the CA mats. The DPPH assay further confirmed the best radical scavenging activity by the trimetallic silica nanohybrid incorporated nanofiber mat (91.77 ± 0.88%). The antimicrobial activity was assessed by using the bacterial ATCC strains of Staphylococcus aureus, Streptococcus pneumoniae, MRSA (Methicillin-resistant Staphylococcus aureus), Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa and fungal strains; quality control samples of Trichophyton rubrum, Microsporum gypsium, and Aspergillus niger, as well as the ATCC strain of Candida albicans. The trimetallic silica nanohybrid-incorporated CA membranes demonstrated the most significant inhibition zones. The reported findings substantiate the self-sterilizing mat's viability, affordability, efficacy against a broad spectrum of microbial strains, cost-effectiveness, and biodegradability. Furthermore, the mat serves as a dual-purpose physical and biological barrier against microbes, affirming its potential impact.
One of the major challenges of testing drugs of abuse is the detection of highly diluted urine samples. The ingestion of a large amount of fluid can considerably reduce the concentration of substances, possibly resulting in inaccurate drug testing. For detection, determination of urinary creatinine is a widely established procedure. In this study, results from the most popular methods, including photospectrometry (Jaffe) and liquid chromatography‐tandem mass spectrometry (LC‐MS/MS), have been compared regarding 327 urine abstinence control samples. Since samples with creatinine concentrations close to the cut‐off of 20 mg/dL are of particular interest, only samples below 50 mg/dL were considered. Results revealed a close correlation of creatinine concentrations by both analytical methods with an R² value of 0.9005. A mean concentration difference of 3.30 ± 3.45 mg/dL was observed, indicating a moderate underestimation by the Jaffe reaction. Graphical analyses showed high accordance between both methods with only a few outliers. Due to easy handling and for economic reasons, the spectrometric method is often preferred over LC‐MS/MS. For urine samples with creatinine concentrations close to the cut‐off, confirmation through a second method should be performed to avoid a possible disadvantage or even severe consequences for the respective individual. It is recommended that each laboratory establishes a reliable verification method.
Dipstick urinalysis is an informative, quick, cost-effective and non-invasive diagnostic tool that is useful in clinical practice for the diagnosis of urinary tract infections (UTIs), kidney diseases, and diabetes. We used dipstick urinalysis as a hands-on microbiology laboratory exercise to reinforce student learning about UTIs with a particular focus on cystitis, which is a common bacterial infection. To avoid exposure to potentially contaminated human urine samples, we prepared artificial urine using easily acquired and affordable ingredients, which allowed less-experienced students to perform urinalysis without the risk of exposure to pathogenic organisms and ensured reliable availability of the urine samples. This practical class taught medical students how to use urinalysis data in conjunction with medical history to diagnose diseases from urine samples and to determine a treatment plan for clinical scenarios.
A bare fused silica capillary lacks enough efficiency for electrophoretic separation under some circumstances as a complex mixture of analogous compounds or stroma matrix. To improve the separation, a strategy of functionalization for the inner surface with nano-silica and polyelectrolytes is proposed in this paper. The results have demonstrated that the hybrid coating film of poly(diallyldimethylammonium chloride) (PDDA)–nano-SiO2–poly(styrenesulfonate) (PSS) on a silica capillary greatly promoted the separation efficiency. As a model, four analytes (naringenin, rutin, quercetin and ascorbic acid) are well separated with 24 mmol L−1 borate buffer solution (pH 8.3) as the carrier. The proposed approach was successfully applied for rapid determination of these analytes in artificial urine with satisfactory results.
As a result of infants' inability to control urination, skin of the diaper area has special needs for protection from irritating effects of urine and prevention of diaper dermatitis such as products for cleansing and protection of the skin. Several in vitro models are currently available to assess tolerance. In vitro testing using artificial urine allows the protective effects of diaper-region cosmetics to be ascertained. Thus, a new model defined as "artificial urine in vitro assay" has been added to our traditional pre-clinical in vitro testing program. IL1-α is a highly active and pleiotropic pro-inflammatory cytokine. It plays a key role in inflammation and is the biological mirror of irritation induced by diaper dermatitis. This study determines, on human skin explants, if a cosmetic formula is (1) as well tolerated in the presence of artificial urine as in its absence and (2) is able to decrease IL1-α production induced by artificial urine or Sodium Dodecyl Sulfate. 31 tests including 17 in-house formulas, 10 bench-markers and 4 combinations of products were performed and data obtained are represented on a simple four-point scale (from practically non protective to very protective). It allows determination of formula-type groups that will have predictable protective properties in subsequent clinical trials and comparison with competitors' products. It is a useful aid at the formulation stage and provides readily-useable data for the cosmetic risk assessment.
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