Incidence of Fit Test Failure During N95 Respirator Reuse and Extended Use.

Importance: The COVID-19 pandemic resulted in a widespread acute shortage of N95 respirators, prompting the Centers for Disease Control and Prevention to develop guidelines for extended use and limited reuse of N95s for health care workers (HCWs). While HCWs followed these guidelines to conserve N95s, evidence from clinical settings regarding the safety of reuse and extended use is limited. Objective: To measure the incidence of fit test failure during N95 reuse and compare the incidence between N95 types. Design, Setting, and Participants: This prospective cohort study, conducted from April 2, 2021, to July 15, 2022, at 6 US emergency departments (EDs), included HCWs who practiced N95 reuse for more than half of their clinical shift. Those who were unwilling to wear an N95 for most of their shift, repeatedly failed baseline fit testing, were pregnant, or had facial hair or jewelry that interfered with the N95 face seal were excluded. Exposures: Wearing the same N95 for more than half of each clinical shift and for up to 5 consecutive shifts. Participants chose an N95 model available at their institution; models were categorized into 3 types: dome (3M 1860R, 1860S, and 8210), trifold (3M 1870+ and 9205+), and duckbill (Halyard 46727, 46767, and 46827). Participants underwent 2 rounds of testing using a different mask of the same type for each round. Main Outcomes and Measures: The primary outcome was Occupational Safety and Health Administration-approved qualitative fit test failure. Trained coordinators conducted fit tests after clinical shifts and recorded pass or fail based on participants tasting a bitter solution. Results: A total of 412 HCWs and 824 N95s were fit tested at baseline; 21 N95s (2.5%) were withdrawn. Participants' median age was 34.5 years (IQR, 29.5-41.8 years); 252 (61.2%) were female, and 205 (49.8%) were physicians. The overall cumulative incidence of fit failure after 1 shift was 38.7% (95% CI, 35.4%-42.1%), which differed by N95 type: dome, 25.8% (95% CI, 21.2%-30.6%); duckbill, 28.3% (95% CI, 22.2%-34.7%); and trifold, 61.3% (95% CI, 55.3%-67.3%). The risk of fit failure was significantly higher for trifold than dome N95s (adjusted hazard ratio, 1.75; 95% CI, 1.46-2.10). Conclusions and Relevance: In this cohort study of ED HCWs practicing N95 reuse, fit failure occurred in 38.7% of masks after 1 shift. Trifold N95s had higher incidence of fit failure compared with dome N95s. These results may inform pandemic preparedness, specifically policies related to N95 selection and reuse practices.

Metal Stabilization of Collagen and de Novo Designed Mimetic Peptides.

We explore the design of metal binding sites to modulate triple-helix stability of collagen and collagen-mimetic peptides. Globular proteins commonly utilize metals to connect tertiary structural elements that are well separated in sequence, constraining structure and enhancing stability. It is more challenging to engineer structural metals into fibrous protein scaffolds, which lack the extensive tertiary contacts seen in globular proteins. In the collagen triple helix, the structural adjacency of the carboxy-termini of the three chains makes this region an attractive target for introducing metal binding sites. We engineered His3 sites based on structural modeling constraints into a series of designed homotrimeric and heterotrimeric peptides, assessing the capacity of metal binding to improve stability and in the case of heterotrimers, affect specificity of assembly. Notable enhancements in stability for both homo- and heteromeric systems were observed upon addition of zinc(II) and several other metal ions only when all three histidine ligands were present. Metal binding affinities were consistent with the expected Irving-Williams series for imidazole. Unlike other metals tested, copper(II) also bound to peptides lacking histidine ligands. Acetylation of the peptide N-termini prevented copper binding, indicating proline backbone amide metal-coordination at this site. Copper similarly stabilized animal extracted Type I collagen in a metal-specific fashion, highlighting the potential importance of metal homeostasis within the extracellular matrix.

In vivo imaging and tracking of individual nanodiamonds in drosophila melanogaster embryos.

In this work, we incorporate and image individual fluorescent nanodiamonds in the powerful genetic model system Drosophila melanogaster. Fluorescence correlation spectroscopy and wide-field imaging techniques are applied to individual fluorescent nanodiamonds in blastoderm cells during stage 5 of development, up to a depth of 40 µm. The majority of nanodiamonds in the blastoderm cells during cellularization exhibit free diffusion with an average diffusion coefficient of (6 ± 3) × 10(-3) µm(2)/s, (mean ± SD). Driven motion in the blastoderm cells was also observed with an average velocity of 0.13 ± 0.10 µm/s (mean ± SD) µm/s and an average applied force of 0.07 ± 0.05 pN (mean ± SD). Nanodiamonds in the periplasm between the nuclei and yolk were also found to undergo free diffusion with a significantly larger diffusion coefficient of (63 ± 35) × 10(-3) µm(2)/s (mean ± SD). Driven motion in this region exhibited similar average velocities and applied forces compared to the blastoderm cells indicating the transport dynamics in the two cytoplasmic regions are analogous.

Determination of total selenium in pharmaceutical and herbal supplements by hydride generation and graphite furnace atomic absorption spectrometry.

The total selenium (Se) was determined in herbal and pharmaceutical supplements used for liver diseases. The total Se contents were determined in different pharmaceutical and herbal supplements by hydride generation atomic absorption spectrometry (HGAAS) and graphite furnace atomic absorption spectrometry (GFAAS) after microwave-assisted acid digestion. The accuracy of the techniques was evaluated by using certified reference material and the standard addition method. The recoveries of total Se were 99.4 and 99.0% for HGAAS and GFAAS, respectively. The precision of the techniques expressed as RSD were 2.34 and 4.54% for HGAAS and GFAAS measurements, respectively. The LOD values for HGAAS and GFAAS were 0.025 and 0.052 pglg, respectively. The concentrations of Se in pharmaceutical and herbal supplements were found in the range of 19.2-53.8 and 25.0-42.5 pg/g, respectively, corresponding to 35-76% and 45-76% of the total recommended dose of Se for adults.

Effects of selenium and zinc status in biological samples of hepatitis C patient after herbal and pharmaceutical supplements.

The use of natural remedies and pharmacological mineral supplements for liver disease treatment has a long history. In present study, the levels of selenium (Se) and zinc (Zn) were determined in biological samples (serum and whole blood) of female hepatitis C patients (n = 132), age ranged 30-45 years, before and after 30 days treatment with herbal/pharmaceutical supplements. For comparative study, 128 age-matched female subjects, residing in the same residential areas and have socioeconomic status, were selected as referents. The Se and Zn in supplements, blood, and sera were determined by atomic absorption spectrometry. It was observed that Zn and Se in blood and serum samples of viral hepatitis C (HCV) patients were reduced in the range of 28.6-39 % and 24-36 %, respectively, as compared to those of referents. After herbal/pharmaceutical supplementations, 20.6-25.0 and 9.15-13.2 % of Zn and 10.6-12.1 and 19.6-21.4 % of Se were enhanced in sera and blood samples of HCV patients, respectively. The resulted data indicated that the levels of Se and Zn in addition to some biochemical parameters were improved in HCV patients after herbal/pharmaceutical supplementation. The effects of both supplements were not significantly different (p > 0.05).

Control of Collagen Stability and Heterotrimer Specificity through Repulsive Electrostatic Interactions.

Charge-pair interactions between acidic and basic residues on the surface of collagen can promote stability as well as control specificity of molecular recognition. Heterotrimeric collagen peptides have been engineered de novo using either rational or computational methods, which in both cases optimize networks of favorable charge-pair interactions in the target structure. Less understood is the role of electrostatic repulsion between groups of like charge in destabilizing structure or directing molecular recognition. To study this, we apply a "charge crowding" approach, where repulsive interactions between multiple aspartate side chains are found to destabilize the homotrimer states in triple helical peptide system and can be utilized to promote the formation of heterotrimers. Neutralizing surface charge by increasing salt concentration or decreasing pH can enhance homotrimer stability, confirming the role of charge crowding on the destabilization of homotrimers via electrostatic repulsion. Charge crowding may be used in conjunction with other approaches to create specific collagen heterotrimers.

Sleep disorders in Behçet's disease, and their relationship with fatigue and quality of life.

Behçet's disease, a systemic vasculitis, can cause varying degrees of activity limitation, fatigue and quality of life impairment. To date, there have been no studies regarding sleep disturbance and its relationship with fatigue and life quality in Behçet's disease. We aimed to evaluate sleep disorders and polysomnographic parameters, and to determine their relationship with fatigue and quality of life in Behçet's disease. Fifty-one patients with Behçet's disease without any neurological involvement were interviewed regarding sleep disorders. Twenty-one subjects with no sleep complaints were included as the control group. Sleep-related complaints were evaluated in a face-to-face interview. Sleep quality, excessive daytime sleepiness, fatigue, depression, anxiety, disease activity/severity, and quality of life questionnaires and an overnight polysomnography were performed. Prevalences of restless legs syndrome (35.3%) and obstructive sleep apnea syndrome with/without other sleep disorders (32.5%) were higher than in the control group and the general population. Fatigue was higher in patients with restless legs syndrome and obstructive sleep apnea syndrome, and in those with lower minimum oxygen saturation; hence, only patients with restless legs syndrome had quality of life impairment. Sleep efficiency index and sleep continuity index were lower, and wake after sleep onset, respiratory disturbance index and apnea-hypopnea index were higher than in controls (P < 0.01). Neither sleep disorders nor polysomnographic parameters were related to disease activity and severity. In conclusion, it is important to question sleep disorder followed by a polysomnography, if necessary, in order to improve quality of life and fatigue in Behçet's disease.

Development of extraction methods for speciation analysis of selenium in aqueous extracts of medicinal plants.

Advanced extraction methods have been developed for direct speciation of dissolved inorganic and organic selenium (Se) species in aqueous extracts of medicinal plants (MPs). The inorganic species of Se (SeIV and SeVI) were separated from organic forms by adsorbing inorganic Se on alumina, while the organic Se was not retained. The retained inorganic Se species was eluted with 10 mL 0.2 M HCl. The total inorganic Se species was determined after prereduction of SeVI into SeIV with concentrated HCl. The SeIV in the eluent and total inorganic Se species were then complexed with diethyldithiocarbamate. The resultant complexes were entrapped in the nonionic surfactant Triton X-114. The total Se, organic Se, total inorganic Se, and SeIV species were determined by electrothermal atomic absorption spectrometry with a modifier. The SeVI concentration was obtained by subtracting SeIV from total inorganic Se contents. The main factors affecting the methodologies were investigated in detail. Under the optimized experimental conditions, the LOD for SeIV was 50 microg/L. Among dissolved inorganic and organic Se species in aqueous extracts of MPs, organic Se species were present in the range of 74-84%, SeIV 3.62-7.47%, and SeVI 12.4-18.57% of total Se contents.

Evaluation of selenium in biological sample of arsenic exposed female skin lesions and skin cancer patients with related to non-exposed skin cancer patients.

The antagonistic effects between selenium (Se) and arsenic (As) suggest that low Se status plays an important role in arsenism development. The objective of present study was to assess Se contents in biological samples of As exposed females have skin lesions and cancer with related to non-exposed skin cancer patients. The biological samples (blood and scalp hair) of As exposed group comprises, female skin cancer (ESC) patients admitted in cancer hospitals have skin lesions (ESL) and exposed referents have not both diseases (ER), belongs to As exposed area of Pakistan. For comparative purposes, age matched female skin cancerous patient (RP) and non-cancerous females (NER) belong to non-exposed areas were also selected. The As and Se in acid digests of biological samples were pre-concentrated by complexing with chelating agent (ammonium pyrrolidinedithiocarbamate), and resulted complexes were extracted into non-ionic extractant (Triton X-114), prior to analysis by electrothermal atomic absorption spectrometry. The enhancement factor of about 25 was obtained by pre-concentrating 10 mL of sample solutions. The accuracy of the optimized procedure was evaluated by using certified reference material (BCR 397) with certified values for Se and As and standard addition method at three concentration levels in real samples. No significant differences was observed (p>0.05) when comparing the values obtained by the proposed method, added and certified values of both elements. The biological samples of ESC patients had 2-3 folds higher As and lower Se levels as compared to RP (p<0.001). Understudied exposed referents have high level of As and lower Se contents as compared to referents subjects of non-exposed area (p<0.01). The higher concentration of As and lower levels of Se in biological samples of cancerous patients are consisted with reported studies.

Inorganic arsenic speciation in groundwater samples using electrothermal atomic spectrometry following selective separation and cloud point extraction.

A method has been developed for speciation of total, total inorganic and organic arsenic (As) species in groundwater samples. The inorganic species of As((III,V)) were separated from organic forms by adsorbing on alumina (Al(2)O(3)) whereas the organic As was eluted out. The retained inorganic As species was eluted by 0.2 M HCl. Then eluent As(III) and As(V) were formed as complexes with ammonium pyrrolidinedithiocarbamate (APDC) and molybdate, respectively. Then As(III)-PDC and As(V)-molybdate complexes were quantitatively extracted into a non-ionic surfactant Triton X-114. The total As was determined by conventional preconcentration procedures. The resulting solutions of each method were determined by ETAAS with modifier. The main factors affecting the separation and cloud point extraction (CPE) were investigated in detail. The limits of detection values were found as 0.04 and 0.20 µg L(-1) for As(III) and As(V), respectively, whereas limits of quantification were observed as 0.13 and 0.33 µg L(-1) for As(III) and As(V), respectively. Standard addition method confirmed the accuracy. The recoveries of As(III) and As(V) were found in the range of 98 - 99%. The proposed method was applied to groundwater samples collected from different areas of Sukkur district.

Determination of arsenic in scalp hair of children and its correlation with drinking water in exposed areas of Sindh Pakistan.

This study was focused on the analysis of arsenic (As) levels in scalp hair of children (age, <10 years) collected from two towns of Khairpur, Pakistan, to evaluate the effects of As-contaminated groundwater. For comparative purposes, scalp hair samples of children were also collected from that area having low levels of As (<10 µg/L) in drinking water. Groundwater and scalp hair samples of children were collected and analyzed by electrothermal atomic absorption spectrometry prior to microwave-assisted acid digestion. The average As concentrations in groundwater samples of two towns, Thari Mirwah and Gambat, were found to be 28.5 and 98.3 µg/L, respectively. The range of As concentrations in scalp hair samples of children who belong to Thari Mirwah and Gambat was 1.25-1.61 µg/g and 1.73-3.63 µg/g, respectively. Twenty percent of the total children who belong to Gambat have skin lesions on their hands and feet. A positive correlation coefficient (R = 0.91-0.99) was obtained between As contents in drinking water and scalp hairs of children of both towns.

Evaluation of arsenic levels in grain crops samples, irrigated by tube well and canal water.

The aim of this study was to evaluate the uptake of arsenic (As) by grain crops (wheat, maize and sorghum) grown on agricultural soil irrigated with tube well water (SIT) as test samples and for comparative purposes, same grain crop samples grown on agricultural soil irrigated with fresh canal water (SIC) were marked as control samples, collected simultaneously from three sub-districts of Khairpur, Pakistan. Moreover, this paper demonstrated the total and EDTA (0.05 M) extractable As in both understudied soils that correlate with the respective total As in the edible parts of the studied grain crops. A significantly high accumulation of As was found in grains grown on SIT as compared to those grown on SIC. This study highlights the increased danger of growing food crops in the agricultural land continuously irrigated by As contaminated ground water.

Zinc and iron determination in serum and urine samples of thyroid patients using cloud point extraction.

A simple and rapid cloud point extraction method was applied for preconcentration of trace quantities of zinc (Zn) and iron (Fe) in biological samples (serum and urine) of thyroid patients prior to determination by flame atomic absorption spectrometry. The metals in serum and urine samples were complexed with 1-(2-thiazolylazo)-2-naphthol and entrapped in the surfactant octylphenoxypolyethoxyethanol (Triton X-114). After centrifugation, the surfactant-rich phase was diluted with 0.1 M HNO3 in methanol. For optimum recovery of analytes, the influences of the analytical parameters, including pH and amounts of complexing and surfactant reagents, were investigated. Enrichment factors of 66.4 and 70.2 were obtained for the preconcentration of Zn(II) and Fe(III), respectively. The obtained results showed sufficient recoveries (>98%) for Zn(II) and Fe(III) in certified reference materials (CRMs). The proposed method was applied to the determination of Zn(II) and Fe(III) in biological (serum and urine) samples and CRMs.

Cloud point extraction of vanadium in pharmaceutical formulations, dialysate and parenteral solutions using 8-hydroxyquinoline and nonionic surfactant.

A cloud point extraction (CPE) method has been developed for the determination of trace quantity of vanadium ions in pharmaceutical formulations (PF), dialysate (DS) and parenteral solutions (PS). The CPE of vanadium (V) using 8-hydroxyquinoline (oxine) as complexing reagent and mediated by nonionic surfactant (Triton X-114) was investigated. The parameters that affect the extraction efficiency of CPE, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of CPE of V was checked by standard addition method in real samples. The extracted surfactant-rich phase was diluted with nitric acid in ethanol, prior to subjecting electrothermal atomic absorption spectrometry. Under these conditions, the preconcentration of 50 mL sample solutions, allowed raising an enrichment factor of 125-fold. The lower limit of detection obtained under the optimal conditions was 42 ng/L. The proposed method has been successfully applied to the determination of trace quantity of V in various pharmaceutical preparations with satisfactory results. The concentration ranges of V in PF, DS and PS samples were found in the range of 10.5-15.2, 0.65-1.32 and 1.76-6.93 microg/L, respectively.

Evaluation of common mutations in the Mediterranean fever gene in Multiple Sclerosis patients: is it a susceptibility gene?

PURPOSE: Multiple Sclerosis (MS) is a disease of the central nervous system characterized by multiple areas of inflammation and demyelination in the white matter of the brain and spinal cord. MEFV gene, which is the main factor in familial Mediterranean fever, is an intracellular regulator of inflammation. This study was designed to determine if known mutations in pyrin domain of MEFV gene are involved in MS and associated with MS morbidity. METHODS: Fifty-three patients with MS and 66 healthy subjects, who were all Turkish, were included in this study. Five pyrin gene mutations (E148Q, M680I, M694V, M694I and V726A) were detected in the patients and controls by using the PRONTO FMF Basic Kit according to the manufacturer's instructions. RESULTS: Pyrin gene mutations were found in 20 of the 53 MS patients (38%) and in seven of the 66 healthy subjects (11%). The frequency of total pyrin domain mutations was significantly higher in the MS patients than in the healthy subjects (p<0.0001). The frequencies of M694V, E148Q and V726A mutations were significantly higher in the patients than in the healthy subjects (p=0.02, p=0.013, p=0.004 respectively). The mean time to reach EDSS score 3.0 was earlier in the patients with MEFV gene mutation (p=0.02) and the relapse rate was slightly higher among the MS patients carrying MEFV gene mutation (p=0.04). CONCLUSION: The results of this study supported the hypothesis that MS patients with MEFV mutation seem to have the susceptibility to develop a more progressive disease. Moreover, these data suggest that MEFV mutations may increase the risk of MS development.

Biosorption studies on powder of stem of Acacia nilotica: Removal of arsenic from surface water.

In present study a biomass derived from the stem of Acacia nilotica has been investigated to remove As ions from surface water samples of different origins (lake, canal and river). The effects of various parameters viz. pH, biosorbent dosage, contact time and temperature on the biosorption processes were systematically studied. Experimental data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. It was observed that As biosorption best fitted to the Langmuir and Freundlich isotherms. The mean sorption energy (E) calculated from D-R model, indicated physico-chemical biosorption. Study of thermodynamic parameters revealed the endothermic, spontaneous and feasible nature of biosorption process. The pseudo-second-order rate equation described better the kinetics of As biosorption with good correlation coefficients than pseudo-first-order equation. The biomass of A. nilotica was found to be effective for the removal of As with 95% sorption efficiency at a concentration of <200 microg/L of As solution, and thus uptake capacity is 50.8 mg As/g of biomass. The A. nilotica biomass could be used as a low-cost biosorbent for As ion removal.

Separation and preconcentration of trace amounts of aluminum ions in surface water samples using different analytical techniques.

A separation/preconcentration of aluminum (III) (Al(3+)) has been developed to overcome the problem of high matrix species, which may interfere with the determination of trace quantity of Al(3+) in natural water samples. The separation of Al(3+) in water samples was carried out from interfering cations by complexing them with 2-methyle 8-hyroxyquinoline (quinaldine) on activated silica. Whereas the separated trace amounts of Al(3+) was preconcentrated by cloud point extraction (CPE), as prior step to its determination by spectrofluorimetry (SPF) and flame atomic absorption spectrometry (FAAS). The Al(3+) react with 8-hydroxyquinoline (oxine) and then entrapped in non-ionic surfactant Triton X-114. The main factors affecting CPE efficiency, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of separation/preconcentration of Al(3+) was checked by certified reference material of water (SRM-1643e). After optimization of the complexation and extraction conditions, a preconcentration factor of 20 was obtained for Al(3+) in 10 mL of natural water samples. The relative standard deviation for 6 replicates containing 100 microg L(-1) of Al(3+) was 5.41 and 4.53% for SPF and FAAS, respectively. The proposed method has been applied for determination of trace amount of Al(3+) in natural water samples with satisfactory results.

Separation and preconcentration of aluminum in parenteral solutions and bottled mineral water using different analytical techniques.

A new method is reported for the separation of aluminum ions [Al(III)] from interfering elements in parenteral and pharmaceutical solutions (PS) and bottled mineral water (BMW) samples, through solid-phase extraction with 2-methyl-8-hydroxyquinoline (quinaldine) adsorbed onto activated silica gel. While the enrichment step of separated Al(III) was carried out by cloud point extraction (CPE) using 8-hydroxyquinoline as complexing reagent, the resulted complex was entrapped in a non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114). The enriched Al(III) in sample solutions were determined by spectrofluorometry (SPF) at lambda(excitation) 370 nm and lambda(emission) 510 nm, and flame atomic absorption spectrometry (FAAS) for comparative purpose. The variables affecting the complexation and extraction steps were studied and optimized. The validity of methodology was checked with certified reference material of water and standard addition method. The enrichment factor and detection limit of Al(III) for the preconcentration of 50 ml of PS and BMW were found to be 100 and 0.25 microg/L, respectively. The proposed method has been applied for the determination of trace amount of Al(III) in PS and BMW samples with satisfactory results. In PS the levels of Al(III) are above than permissible limit (25 microg/L).

[Acute intoxication by cosmetics]. / Les intoxications aiguës par les cosmétiques

Intoxications due to cosmetics are of various types, but certain substances may be particularly harmful, especially when the constituants include acetone, boric acid and borates, ethyl alcohol, bromates, formol, methyl alcohol, propylene glycol, thallium, thioglycolate.. Every cosmetic substance may induce accidental intoxications. Most often, fluid cosmetics are absorbed either by children or by feeble-minded subjects. In all intoxication, one must take account of the age and weight of the patient, of the quantity absorbed, of the toxicity and of the constituants of the substance.