Cost-effectiveness of patch testing allergens within the same group: A computational approach to optimize formaldehyde-related allergen selection.

BACKGROUND: Patch testing for multiple cross-reactive allergens for allergic contact dermatitis (ACD) may not be necessary because of copositivity. OBJECTIVES: We evaluated the formaldehyde group allergens to determine the optimal, most cost-effective allergens to test. METHODS: A retrospective analysis of Mayo Clinic (1997-2022) examined the well-established copositive formaldehyde group: formaldehyde, quaternium 15, hexahydro-1,3,5-tris(2-hydroxyethyl)triazine, diazolidinyl urea, imidazolidinyl urea, toluenesulphonamide formaldehyde resin, DMDM hydantoin, and ethyleneurea melamine formaldehyde mix. Patch Optimization Platform identified which single formaldehyde-related allergen optimally captures patients with clinically relevant ACD. Next, Patch Optimization Platform determined the optimal additional 1, 2, 3, etc. allergens. Cost per patch test was $5.19 (Medicare 2022). RESULTS: A total of 9832 patients were tested for all listed allergens, with 830 having positive patch test results. Patch Optimization Platform determined that quaternium 15 alone captures 53% of patients with ACD to the formaldehyde group; adding the optimal second allergen (formaldehyde 1%) captures 78%; the optimal 5 top allergens capture >94% of patients. The incremental cost per additional diagnosis increased up to 44-fold as the number of allergens tested increased. LIMITATIONS: Data are from a single institution, and the cost per test was fixed according to Medicare Part B in 2022. CONCLUSIONS: For diagnosing ACD, we recommend considering an optimized allergen selection algorithm.

Cost-effectiveness of methenamine hippurate compared with antibiotic prophylaxis for the management of recurrent urinary tract infections in secondary care: a multicentre, open-label, randomised, non-inferiority trial.

OBJECTIVES: To estimate the cost-effectiveness of methenamine hippurate compared with antibiotic prophylaxis in the management of recurrent urinary tract infections. DESIGN: Multicentre, open-label, randomised, non-inferiority trial. SETTING: Eight centres in the UK, recruiting from June 2016 to June 2018. PARTICIPANTS: Women aged ≥18 years with recurrent urinary tract infections, requiring prophylactic treatment. INTERVENTIONS: Women were randomised to receive once-daily antibiotic prophylaxis or twice-daily methenamine hippurate for 12 months. Treatment allocation was not masked and crossover between arms was allowed. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary economic outcome was the incremental cost per quality-adjusted life year (QALY) gained at 18 months. All costs were collected from a UK National Health Service perspective. QALYs were estimated based on responses to the EQ-5D-5L administered at baseline, 3, 6, 9, 12 and 18 months. Incremental costs and QALYs were estimated using an adjusted analysis which controlled for observed and unobserved characteristics. Stochastic sensitivity analysis was used to illustrate uncertainty on a cost-effectiveness plane and a cost-effectiveness acceptability curve. A sensitivity analysis, not specified in the protocol, considered the costs associated with antibiotic resistance. RESULTS: Data on 205 participants were included in the economic analysis. On average, methenamine hippurate was less costly (-£40; 95% CI: -684 to 603) and more effective (0.014 QALYs; 95% CI: -0.05 to 0.07) than antibiotic prophylaxis. Over the range of values considered for an additional QALY, the probability of methenamine hippurate being considered cost-effective ranged from 51% to 67%. CONCLUSIONS: On average, methenamine hippurate was less costly and more effective than antibiotic prophylaxis but these results are subject to uncertainty. Methenamine hippurate is more likely to be considered cost-effective when the benefits of reduced antibiotic use were included in the analysis. TRIAL REGISTRATION NUMBER: ISRCTN70219762.

Effect of methenamine hippurate shortage on antibiotic prescribing for urinary tract infections in Norway-an interrupted time series analysis.

BACKGROUND: Despite a lack of conclusive evidence of effect, methenamine hippurate is widely prescribed as preventive treatment for recurrent urinary tract infections (UTIs) in Norway. A national discontinuation of methenamine hippurate treatment due to a 4-month drug shortage in 2019 presented an opportunity to evaluate its preventive effect on UTIs among regular users. OBJECTIVE: To estimate the impact of the methenamine hippurate drug shortage on prescription frequency of UTI antibiotics. METHODS: Data from The Norwegian Prescription Database was analysed using an interrupted time series design. The time series consisted of 56 time periods of 14 days. The model included two naturally occurring interruptions: (i) the methenamine hippurate drug shortage, and (ii) reintroduction of the drug. The study population were 18 345 women ≥50 years receiving ≥2 prescriptions of methenamine hippurate in the study period before the shortage. Main outcome measure was number of prescriptions of UTI antibiotics per 1000 methenamine hippurate users. Prescription rates of antibiotics for respiratory tract infections were analysed to assess external events affecting antibiotic prescribing patterns. RESULTS: We found a significant increase of 2.41 prescriptions per 1000 methenamine hippurate users per 14-day period during the drug shortage (95%CI 1.39, 3.43, P < 0.001), followed by a significant reduction of -2.64 prescriptions after reintroduction (95%CI -3.66, -1.63, P < 0.001). CONCLUSIONS: During the methenamine hippurate drug shortage, we found a significant increase in prescribing trend for UTI antibiotics followed by a significant decrease in prescribing trend after reintroduction. This change in trend seems to reflect a preventive effect of the drug on recurrent UTIs.

Use of Methenamine for Urinary Tract Infection Prophylaxis: Systematic Review of Recent Evidence.

INTRODUCTION AND HYPOTHESIS: Antibiotic resistance is an unavoidable consequence of antibiotic use and growing rates of resistance are an urgent issue. Methenamine is a non-antibiotic alternative used for urinary tract infection (UTI) prophylaxis. The objective of this review is to evaluate recently published literature regarding the efficacy and safety of methenamine for UTI prophylaxis. METHODS: PubMed, Embase, and CENTRAL databases were queried in March 2023 using the following search terms: urinary tract infection, cystitis, bacteriuria, or dysuria, and methenamine. Studies prior to 2012 were excluded from this review to focus on appraisal of the most recent evidence. Prospective and controlled retrospective trials were included for review. RESULTS: A total of seven studies (three prospective and four retrospective) met the inclusion criteria for review. Two of the 3 prospective studies demonstrated no or non-inferior differences in clinical efficacy to prevent recurrent UTIs between methenamine and antibiotic prophylaxis and the third showed decreased rates of UTI with methenamine use in patients with short-term indwelling catheters compared with cranberry alone. The retrospective studies consistently supported the efficacy and safety of methenamine for UTI prophylaxis in a variety of populations and clinical settings. Adverse effects reported with methenamine were similar to comparators and included nausea, abdominal pain, and headache. CONCLUSIONS: The use of methenamine for UTI prophylaxis was shown to be effective in a variety of settings without an increased risk of adverse effects compared with prophylactic antibiotics. Larger blinded clinical trials are needed to further define the role of methenamine in UTI prophylaxis.

Evaluating quaternium-15 effects on Mytilus galloprovincialis: New insights on physiological and cellular responses.

Among personal care products, quaternium-15 is prominently featured as a preservative in items such as shampoos, soaps, shaving products, and cosmetics. The widespread use of these products in people's daily routines contributes to quaternium-15 release into aquatic ecosystems. In this context, the primary aim of the study was to assess the physiological and cellular responses of the digestive gland and gills in Mytilus galloprovincialis to quaternium-15 exposure. Cell viability and the ability of digestive gland cells to regulate their volume were evaluated. Additionally, the expression of the genes involved in oxidative stress response was assessed to further substantiate the compound's harmful effects. Results indicated a significant decrease in both the viability of digestive gland cells and their RVD (regulatory volume decrease) capacity when exposed to a hypotonic solution. Furthermore, impairment of digestive gland cell function was corroborated by the modulation of oxidative stress-related gene expression, including SOD, Cat, as well as Hsp70 and CYP4Y1. Similar gene expression alterations were observed in the gills, reflecting impaired functionality in this vital organ as well. In summary, the outcomes of the study provide conclusive evidence of the toxicity of quaternium-15. This underscores the urgent need to further investigate the toxicological effects of this contaminant on aquatic ecosystems and emphasises the necessity of limiting the use of products containing quaternium-15.

Morphological and etiological analyses of C3 and non-C3 glomerulonephritis in primary membranoproliferative glomerulonephritis using periodic acid-methenamine silver stain electron microscopy: a retrospective multicentered study.

This study elucidated the etiology of C3 glomerulonephritis (C3GN) and non-C3GN with primary membranoproliferative glomerulonephritis (MPGN) using transmission electron microscopy (TEM) and periodic acid-methenamine silver stain (PAM-EM). Thirty-one primary MPGN cases were analyzed by TEM and PAM-EM to distinguish among MPGN I, MPGN II, MPGN III Burkholder subtype (MPGN IIIB), and Anders and Strife subtype (MPGN IIIA/S). Each case was also classified into C3GN or non-C3GN according to the standard C3GN definition using immunostaining. Four cases of MPGN II met C3 glomerulopathy; whereas, four cases of MPGN IIIB did not meet C3 glomerulopathy. Seven of 11 cases (64%) of MPGN I without GBM disruption and 7 of 12 cases (58%) of MPGN IIIA/S with GBM disruption met the non-C3GN criteria with significant immunoglobulins' deposition. Regardless of the C3GN or non-C3GN diagnosis, the deposits in primary MPGN I and MPGN IIIA/S exhibited ill-defined, amorphous, and foggy characteristics similar to those found in postinfectious GN but were different from immune complex (IC) deposits seen in MPGN IIIB. Not only C3GN but also non-C3GN was due to mechanisms other than IC deposition as found in postinfectious GN. Consequently, GBM disruption of MPGN IIIA/S was not due to IC deposition.

Methenamine for urinary tract infection prophylaxis: A systematic review.

Urinary tract infections (UTIs) commonly affect many patient populations. Recurrent UTIs (rUTIs) can be particularly problematic and lead to potential hospitalizations, multiple antibiotic courses, and have a potential negative impact on quality of life. To prevent UTIs, antibiotics are frequently used for prophylaxis; however, antibiotic prophylaxis has notable untoward consequences including but not limited to potential adverse effects and development of antibiotic resistance. Methenamine, an antiseptic agent initially available in 1967, has re-emerged as a potential option for UTI prophylaxis in various populations, including older adults and renal transplant recipients. The objective of this systematic review was to evaluate the clinical effectiveness and safety of methenamine for UTI prophylaxis. A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance was performed. A PubMed, Embase, and Cochrane library search was conducted to identify relevant English-language studies evaluating methenamine for UTI prophylaxis including randomized controlled trials, case-control studies, and meta-analyses through June 2023. Articles were excluded if the studies did not primarily describe or evaluate methenamine for UTI prophylaxis, were commentaries/viewpoints articles, point prevalence studies, review articles, studies that evaluated methenamine used with another agent, and any duplicate publications from searched databases. A total of 11 articles were identified for inclusion. This systematic review suggests methenamine generally appears to be an effective and well-tolerated antibiotic-sparing option for UTI prophylaxis. Furthermore, the pharmacology, dosage and formulation, warnings, precautions, and safety considerations of methenamine that provide potential clinical considerations regarding its use for UTI prophylaxis are described. Further studies are needed to evaluate the clinical utility of methenamine for UTI prophylaxis.

Synthesis and Application of Carbon Quantum Dots Derived from Carbon Black in Bioimaging.

Carbon quantum dots (CQDs) are a new type of fluorescent QDs that consists mainly of carbon atoms. In this research, CQDs were synthesized through harsh oxidizing conditions applied on carbon black and subsequent N-doping using hexamethylenetetramine (Hexamine) and polyethyleneimine (PEI). The synthesized CQDs were characterized using FTIR, AFM, UV-Visible spectroscopy, photoluminescence (PL) spectroscopy, and fluorescence imaging respectively. The AFM images showed that the dots are in the range of 2-8 nm. N-doping of the CQDs increased the PL intensity. The PL enhancement for the CQDs that were N-doped with PEI was higher compared to those N-doped with hexamine. The shift in PL by changing the excitation wavelength has been attributed to the nano-size of the CQDs, functional groups, defect traps, and quantum confinement effect. The in vitro fluorescence imaging revealed that N-doped CQDs can internalize into the cells and be used for fluorescent cell imaging.

Effective interactions and phase behavior of protein solutions in the presence of hexamine cobalt(III) chloride.

It is well established that deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) exhibit a reentrant condensation (RC) phase behavior in the presence of the trivalent hexamine cobalt(III) cations (Hac) which can be important for their packing and folding. A similar behavior can be observed for negatively charged globular proteins in the presence of trivalent metal cations, such as Y3+ or La3+. This phase behavior is mainly driven by charge inversion upon an increasing salt concentration for a fixed protein concentration (cp). However, as Hac exhibits structural differences compared to other multivalent metal cations, with six ammonia ligands (NH3) covalently bonded to the central cobalt atom, it is not clear that Hac can induce a similar phase behavior for proteins. In this work, we systematically investigate whether negatively charged globular proteins ß-lactoglobulin (BLG), bovine serum albumin (BSA), human serum albumin (HSA) and ovalbumin (OVA) feature Hac-induced RC. Effective protein-protein interactions were investigated by small-angle X-ray scattering. The reduced second virial coefficient (B2/B2HS) was obtained as a function of salt concentration. The virial coefficient analysis performed confirms the reentrant interaction (RI) behavior for BLG without actually inducing RC, given the insufficient strengths of the interactions for the latter to occur. In contrast, the strength of attraction for BSA, HSA and OVA are too weak to show RC. Model free analysis of the inverse intensity [Formula: see text] also supports this finding. Looking at different q-range by employing static (SLS) and dynamic light scattering experiments, the presence of RI behavior can be confirmed. The results are further discussed in view of metal cation binding sites in nucleic acids (DNA and RNA), where Hac induced RC phase behavior.

[Efectividad de la suspensión bacteriana sublingual en la prevención de infecciones de vías aéreas de repetición en pediatría].

Background: Upper respiratory tract infections (URIs) are very common in the pediatric population. Most of these infections are mild, but due to their chronicity they affect quality of life (QoL), in addition to high costs for medical care. The use of bacterial extracts (BE) that stimulate general immunity can reduce its frequency and improve the QoL of the patient. Objective: Evaluate the effectiveness of a BE in the prevention of ARVI in children from 1 to 6 years of age. Methods: Children between the ages of 1 and 6 years, with a diagnosis of RAVI, were randomized into 3 different groups, with medical follow-up at 6 and 12 weeks after the start. The EB was administered with different doses to each group. An ANOVA test with a Tukey post hoc is used for multiple comparisons (maximum type I error of 0.05). Results: 33 children (12 girls) with a mean age of 3.11 years were included. The average frequency of RAVI prior to treatment was 2.2 events/month and 0.9 and 0.4 events/month at 6 and 12 weeks, respectively. The IVARS were reduced by 76.9% at 3 months of treatment. (Graph). No adverse effects were reported. Conclusions: BE is safe and effective in reducing the frequency of RAVI in children, in agreement with the literature. There is not enough published scientific evidence, but the BE seems to have an application in the prevention and treatment of RAVI. Sublingual administration is comfortable in this age group.

Antecedentes: Las infecciones de vías aéreas superiores (IVASR) son muy frecuentes en la población pediátrica. La mayoría de estas infecciones son leves, pero por la cronicidad afectan la calidad de vida (CdV), además de elevados costos por la atención médica. El uso de extractos bacterianos (EB) que estimulen la inmunidad general pueden reducir su frecuencia y mejorar la CdV del paciente. Objetivo: Evaluar la efectividad de un EB en la prevención de IVASR en niños de 1 a 6 años. Métodos: Se aleatorizaron niños entre 1 y 6 años, con diagnóstico IVASR en 3 grupos distintos, seguimiento médico a las 6 y 12 semanas tras el inicio. El EB se administró con dosis distintas a cada grupo. Se utiliza una prueba de ANOVA con un post hoc Tukey para comparaciones múltiples (error tipo I máximo de 0.05). Resultados: Se incluyeron 33 niños (12 niñas) con una media de edad de 3.11 años. La frecuencia de IVASR previo al tratamiento en promedio fue de 2.2 eventos/mes y de 0.9 y de 0.4 eventos/mes a las 6 y 12 semanas respectivamente. La IVARS se redujeron un 76.9% a los 3 meses de tratamiento. (Gráfica). No se reportaron efectos adversos. Conclusiones: El EB es seguro y efectivo en disminuir la frecuencia de IVASR en niños en concordancia con la literatura. No hay suficiente evidencia científica publicada pero el EB parece tener aplicación en la prevención y tratamiento de las IVASR. La administración sublingual es cómoda en este grupo etario.

Efficacy of methenamine with methylthioninium in the treatment of dysuria: a randomized clinical study.

INTRODUCTION AND HYPOTHESIS: Dysuria is a common symptom present in several urological and gynecological conditions. Management relies on the underlying disease but may require additional symptomatic treatment. This study evaluated the combination of methenamine 250 mg and methylthioninium chloride 20 mg in the treatment of dysuria versus phenazopyridine. METHODS: This was a multicenter, single-blind, randomized, superiority clinical trial, including individuals over 18 with dysuria and a score ≥ 5 points on the pre-treatment categorical scale for pain. The primary outcome was the proportion of participants presenting excellent clinical response within 24 h after treatment. Improvement up to 72 h, time to reach improvement, sustained healing, investigators' opinion, and safety were also evaluated. RESULTS: Three hundred and fifteen participants were evaluated. Demographic characteristics and symptoms of dysuria were comparable between groups at baseline. The difference in the excellent response rate between treatments within 24 h was 12.7% (95% CI 6.16, 19.21) for pain, 9.4% (95% CI 3.32, 15.39) for burning, and 12.7% (95% CI 6.37, 18.99) for burning on urination, all in favor of the test drug, which was also superior from 36 to 48 h. Treatments were similar concerning time to reach the absence of symptoms and in the percentage of participants with sustained healing after 72 h. CONCLUSIONS: The association of methenamine with methylthioninium is superior to phenazopyridine in the treatment of dysuria.

A biocatalytic platform for asymmetric alkylation of α-keto acids by mining and engineering of methyltransferases.

Catalytic asymmetric α-alkylation of carbonyl compounds represents a long-standing challenge in synthetic organic chemistry. Herein, we advance a dual biocatalytic platform for the efficient asymmetric alkylation of α-keto acids. First, guided by our recently obtained crystal structures, we develop SgvMVAV as a general biocatalyst for the enantioselective methylation, ethylation, allylation and propargylation of a range of α-keto acids with total turnover numbers (TTNs) up to 4,600. Second, we mine a family of bacterial HMTs from Pseudomonas species sharing less than 50% sequence identities with known HMTs and evaluated their activities in SAM regeneration. Our best performing HMT from P. aeruginosa, PaHMT, displays the highest SAM regeneration efficiencies (TTN up to 7,700) among HMTs characterized to date. Together, the synergistic use of SgvMVAV and PaHMT affords a fully biocatalytic protocol for asymmetric methylation featuring a record turnover efficiency, providing a solution to the notorious problem of asymmetric alkylation.

The resurgence of methenamine hippurate in the prevention of recurrent UTIs in women- a systematic review.

PURPOSE OF REVIEW: Recurrent urinary tract infections (rUTIs) in women are prevalent and difficult to manage. The rise of antimicrobial resistance makes it prudent to re-investigate the role of nonantimicrobial agents in the prevention of RUTIs. We wanted to evaluate randomised controlled trials (RCTs) that employed methenamine hippurate as a therapy or prophylactic in adult women with rUTIs. RECENT FINDINGS: Relevant databases were searched for RCTs using Cochrane methodology and reporting items for systematic reviews and meta-analyses (PRISMA) checklist, comparing the efficacy of methenamine hippurate to either an antibiotic or a placebo for the prophylaxis of rUTI in women.Six trials involving 322 patients taking methenamine and 419 patients receiving antibiotics in total were evaluated. The duration of the trials ranged from 12-24 months. Studies reported that methenamine was effective in extending the mean period between symptomatic episodes of urinary tract infections (UTIs), keeping the patient symptom- and infection-free, and reducing the number of UTI episodes. The newer studies reported that methenamine reduced the incidence rates of recurrent UTIs and was not inferior to the antibiotic in this regard. SUMMARY: The outcomes of methenamine hippurate were found to be at par with the antibiotic prophylaxis. It might serve as a suitable alternative nonantibiotic prophylaxis for females with rUTIs.

Standardization of Grocott's methenamine (hexamine) silver method for glycogen demonstration in liver tissue.

Demonstration of glycogen can be done in different lesions and is considered diagnostically significant, mainly in some tumors. Glycogen staining is affected by the type of fixative, the temperature of fixation, and the staining technique.Grocott's methenamine (hexamine) silver technique quality was assessed after four different types of fixatives at two different temperatures [Bouin's solution, 10% neutral buffered formalin (NBF), 80% alcohol, and Rossman's solution at room temperature (RT) and 4 °C, for 24 h]. These variables were studied to optimize this technique for glycogen demonstration. Archived paraffin blocks were used in this study. They were prepared from one rabbit's liver, and 32 paraffin sections were prepared and stained with Grocott's methenamine (hexamine) silver technique. Eighty percent alcohol provided the highest staining quality scores at both RT and 4 °C in comparison with the other fixatives. We concluded that 80% alcohol at 4 °C seems to be the fixative of choice for glycogen with the Grocott's methenamine (hexamine) silver technique at the level of this study.

The management of recurrent urinary tract infections within a nurse-led urology team.

The aim of this article is to share experience and learning of managing recurrent urinary tract infections (UTIs) within a specialist urology nurse-led team based at a district general hospital. It looks at current practice and supporting evidence for how to manage and treat recurrent UTIs in both male and female patients. Two case studies are presented to illustrate the management strategies and outcomes, demonstrating a planned approach that informs the design of a local management guideline to organise patients' care.

Anthracite based activated carbon impregnated with HMTA as an effectiveness adsorbent could significantly uptake gasoline vapors.

In this study, we synthesized and employed the amine impregnated activated carbon as an efficacious adsorbent for uptaking gasoline vapor. For this regard, anthracite as activated carbon source and hexamethylenetetramine (HMTA) as amine were selected and utilized. Physiochemical characterization of made sorbents were evaluated and investigated using SEM, FESEM, BET, FTIR, XRD, zeta potential, and elemental analysis. The synthesized sorbents provided an excellent textural features as compared with the literature and other activated carbon based sorbents and impregnated with amine. Our findings also suggested that in addition to high surface area (up to 2150 m2 / g), the micro- meso pores created (Vmeso / V micro = 0.79 Cm 3 / g) surface chemistry may significantly affect the gasoline sorption capacity, which here the role of mesoporous is further highlighted. V meso for amine impregnated sample and free activated carbon was 0.89 and 0.31 Cm 3 / g, respectively. According to the results, the prepared sorbents have a potential capability in uptaking gasoline vapor and with line this, we report a high sorption capacity of 572.56 mg / g. After, four cycles used the sorbent had a high durability and about 99.11% of the initial uptake was maintained. Taking together the synthesized adsorbents as an activated carbon provided an excellent and unique features and enhanced gasoline uptake, therefore its applicability in uptaking gasoline vapor can be substantially considered.

Evidence-based review of nonantibiotic urinary tract infection prevention strategies for women: a patient-centered approach.

PURPOSE OF REVIEW: There is a growing interest in nonantibiotic prevention strategies for recurrent urinary tract infections (rUTIs). Our objective is to provide a focused, pragmatic review of the latest evidence. RECENT FINDINGS: Vaginal estrogen is well tolerated and effective for preventing rUTI in postmenopausal women. Cranberry supplements at sufficient doses are effective in preventing uncomplicated rUTI. Methenamine, d -mannose, and increased hydration all have evidence to support their use, although the evidence is of somewhat variable quality. SUMMARY: There is sufficient evidence to recommend vaginal estrogen and cranberry as first-line rUTI prevention strategies, particularly in postmenopausal women. Prevention strategies can be used in series or in tandem, based on patient preference and tolerance for side effects, to create effective nonantibiotic rUTI prevention strategies.