In vitro evaluation of crosslinked bovine pericardium as potential scaffold for the oral cavity.

BACKGROUND: Bovine pericardium (BP) is a scaffold widely used in soft tissues regeneration; however, its calcification in contact with glutaraldehyde, represent an opportunity for its application in hard tissues, such as bone in the oral cavity. OBJECTIVE: To develop and to characterize decellularized and glutaraldehyde-crosslinked bovine pericardium (GC-BP) as a potential scaffold for guided bone regeneration GBR. METHODS: BP samples from healthy animals of the bovine zebu breed were decellularized and crosslinked by digestion with detergents and glutaraldehyde respectively. The resulting cell-free scaffold was physical, chemical, mechanical, and biologically characterized thought hematoxylin and eosin staining, DNA quantification, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), uniaxial tensile test, cell viability and live and dead assay in cultures of dental pulp stem cells (DPSCs). RESULTS: The decellularization and crosslinking of BP appeared to induce conformational changes of the CLG molecules, which led to lower mechanical properties at the GC-BP scaffold, at the same time that promoted cell adhesion and viability of DPSCs. CONCLUSION: This study suggests that the decellularized and GC-BP is a scaffold with the potential to be used promoting DPSCs recruitment, which has a great impact on the dental area.

The influence of glutaraldehyde on the microscopic structure of human pericardium.

OBJECTIVES: In our study, we investigate the collagen structure of human pericardium microscopically in dependence of glutaraldehyde (GA) concentration and fixation time. METHODS: Pericardial samples were taken from 9 patients aged 40+ years who underwent cardiac surgery, either coronary artery bypass surgery or valve implantation/reconstruction. Specimens were cut in 5 equal pieces and treated with GA at fixed concentrations (0.3125%, 0.625%, or 1.25%) but different exposer times (5 min, 10 min, 20 min, 30 min, and 60 min). Elastica van Gieson (EvG) staining was used for microscopic examination of pericardial collagen structure. RESULTS: The collagen structure studied microscopically depended on both GA incubation time and GA concentration. At low GA concentrations (0.3125%, 0.625%) and short incubation times, individual collagen fibers appeared separately. After one hour incubation period, single collagen fibers could not be distinguished at any GA concentration. For fixed incubation times no differences were seen in the collagen structure when 0.3125% and 0.625% GA were used. However, at a concentration of 1.25% GA fusion of individual collagen fibers was already observed at low incubation times. CONCLUSION: Pericardial collagen structure changes with increasing incubation time and increasing GA concentration by raising fusion of single fibers. For GA concentrations of ≤0.625%, fiber fusion depends plainly on incubation time. That is relevant as this concentration is used in cardiac surgery. At a concentration of 1.25% GA, single collagen fibers could not be separated, even at short incubation times. Fusion of individual collagen fibers and changes in appearance (less undulating) were assumed to be responsible for stiffening of GA-fixed pericardium.

Characterization of Exposure to Cleaning Agents Among Health Workers in Two Southern African Tertiary Hospitals.

BACKGROUND: Whilst cleaning agents are commonly used in workplaces and homes, health workers (HWs) are at increased risk of exposure to significantly higher concentrations used to prevent healthcare-associated infections. Exposure assessment has been challenging partly because many are used simultaneously resulting in complex airborne exposures with various chemicals requiring different sampling techniques. The main objective of this study was to characterize exposures of HWs to various cleaning agents in two tertiary academic hospitals in Southern Africa. METHODS: A cross-sectional study of HWs was conducted in two tertiary hospitals in South Africa (SAH) and Tanzania (TAH). Exposure assessment involved systematic workplace observations, interviews with key personnel, passive personal environmental sampling for aldehydes (ortho-phthalaldehyde-OPA, glutaraldehyde and formaldehyde), and biomonitoring for chlorhexidine. RESULTS: Overall, 269 samples were collected from SAH, with 62 (23%) collected from HWs that used OPA on the day of monitoring. OPA was detectable in 6 (2%) of all samples analysed, all of which were collected in the gastrointestinal unit of the SAH. Overall, department, job title, individual HW use of OPA and duration of OPA use were the important predictors of OPA exposure. Formaldehyde was detectable in 103 (38%) samples (GM = 0.0025 ppm; range: <0.0030 to 0.0270). Formaldehyde levels were below the ACGIH TLV-TWA (0.1 ppm). While individual HW use and duration of formaldehyde use were not associated with formaldehyde exposure, working in an ear, nose, and throat ward was positively associated with detectable exposures (P-value = 0.002). Glutaraldehyde was not detected in samples from the SAH. In the preliminary sampling conducted in the TAH, glutaraldehyde was detectable in 8 (73%) of the 11 samples collected (GM = 0.003 ppm; range: <0.002 to 0.028). Glutaraldehyde levels were lower than the ACGIH's TLV-Ceiling Limit of 0.05 ppm. p-chloroaniline was detectable in 13 (4%) of the 336 urine samples (GM = 0.02 ng/ml range: <1.00 to 25.80). CONCLUSION: The study concluded that detectable exposures to OPA were isolated to certain departments and were dependent on the dedicated use of OPA by the HW being monitored. In contrast, low-level formaldehyde exposures were present throughout the hospital. There is a need for more sensitive exposure assessment techniques for chlorhexidine given its widespread use in the health sector.

Modeling the response of exogenously crosslinked tissue to cyclic loading: The effects of permanent set.

Bioprosthetic heart valves (BHVs), fabricated from exogenously crosslinked collagenous tissues, remain the most popular heart valve replacement design. However, the life span of BHVs remains limited to 10-15 years, in part because the mechanisms that underlie BHV failure remain poorly understood. Experimental evidence indicates that BHVs undergo significant changes in geometry with in vivo operation, which lead to stress concentrations that can have significant impact on structural damage. These changes do not appear to be due to plastic deformation, as the leaflets only deform in the elastic regime. Moreover, structural damage was not detected by the 65 million cycle time point. Instead, we found that this nonrecoverable deformation is similar to the permanent set effect observed in elastomers, which allows the reference configuration of the material to evolve over time. We hypothesize that the scission-healing reaction of glutaraldehyde is the underlying mechanism responsible for permanent set in exogenously crosslinked soft tissues. The continuous scission-healing process of glutaraldehyde allows a portion of the exogenously crosslinked matrix, which is considered to be the non-fibrous part of the extra-cellular matrix, to be re-crosslinked in the loaded state. Thus, this mechanism for permanent set can be used to explain the time evolving mechanical response and geometry of BHVs in the early stage. To model the permanent set effect, we assume that the exogenously crosslinked matrix undergoes changes in reference configurations over time. The changes in the collagen fiber architecture due to dimensional changes allow us to predict subsequent changes in mechanical response. Results show that permanent set alone can explain and, more importantly, predict how the mechanical response of the biomaterial change with time. Furthermore, we found is no difference in permanent set rate constants between the strain controlled and the stress controlled cyclic loading studies. An important finding we have is that the collagen fiber architecture has a limiting effect on the maximum changes in geometry that the permanent set effect can induce. This is due to the recruitment of collagen fibers as the changes in geometry due to permanent set increase. This means we can potentially optimize the BHV geometry based on the predicted the final BHV geometry after permanent set has largely ceased. Thus, we have developed the first structural constitutive model for the permanent set effect in exogenously crosslinked soft tissue, which can help to simulate BHV designs and reduce changes in BHV geometry during cyclic loading and thus potentially increasing BHV durability.

Determination of glutaraldehyde in water samples by headspace solid-phase microextraction and gas chromatography-mass spectrometry after derivatization with 2,2,2-trifluoroethylhydrazine.

A simple and convenient headspace solid-phase microextraction (HS-SPME) gas chromatography mass spectrometry (GC-MS) method was described for the determination of glutaraldehyde in water. Glutaraldehyde in water reacted with 2,2,2-trifluoroethylhydrazine (TFEH) in a headspace vial and the formed TFEH derivatives were vaporized and adsorbed onto a fiber. The optimal HS-SPME conditions were achieved with a 50/30µm-divinylbenzene-carboxen-polydimethylsiloxane fiber, 0.06% 2,2,2-TFEH, 25% salt, an extraction/derivatization temperature of 80°C, a heating time of 30min, and a pH of 6.5. The desorption was performed for 1min at 240°C. Under the established conditions, the lowest limits of detection were 0.3µg/L and 0.1µg/L in 6.0mL of surface water and drinking water, respectively, and the intra- and inter-day relative standard deviation was less than 9.1% at concentrations of 50, 100 and 500µg/L. The calibration curve showed good linearity with R=0.9995 and R=0.9993 in surface water and drinking water, respectively. This method is simple, amenable to automation and environmentally friendly.

Concentrations and stability of methyl methacrylate, glutaraldehyde, formaldehyde and nickel sulfate in commercial patch test allergen preparations.

BACKGROUND: Epicutaneous patch tests are used to reproduce allergy and diagnose allergic contact dermatitis. Reliable allergen test preparations are required. OBJECTIVES: The purpose of the present study was to measure the actual concentrations of nickel(II) sulfate hexahydrate (NiSO4 ), methyl methacrylate, formaldehyde, and glutaraldehyde, and to compare them with the labelled concentrations, in commercial patch test allergen preparations found in dermatology clinics where patch testing is routinely performed. MATERIALS AND METHODS: The commercial in-date and out-of-date patch test allergen preparations concentrations of NiSO4 , methyl methacrylate, formaldehyde and glutaraldehyde from one to three participating clinics were analysed with chromatographic or wet chemical techniques. RESULTS: NiSO4 and formaldehyde concentrations were at or above the labelled concentrations; however, formaldehyde loss occurred with storage. NiSO4 particulate was uniformly distributed throughout the petrolatum. 'In-use' methyl methacrylate reagent syringes all contained ≤ 56% of the 2% label concentration, with no observable relationship with expiration date. Lower methyl methacrylate cocentrations were consistently measured at the syringe tip end, suggesting loss resulting from methyl methacrylate's volatility. The concentrations of glutaraldehyde patch test allergen preparations ranged from 27% to 45% of the labelled (1% in pet.) concentration, independently of expiration date. CONCLUSIONS: Some false-negative methyl methacrylate, formaldehyde or glutaraldehyde patch test results may be attributable to instability of the test preparations.

Oral delivery of exenatide via microspheres prepared by cross-linking of alginate and hyaluronate.

Exenatide is an FDA-approved glucose-lowering peptide drug for the treatment of type 2 diabetes by subcutaneous injection. To address the issues on the inconvenience for patient use and the difficulty of oral administration of peptide drugs, chemical cross-linking of two pH-responsive biomaterials, alginate and hyaluronate, was carried out to prepare a new material for the encapsulation of exenatide as a form of microspheres. The exenatide-loaded microspheres exhibited spherical structures with excellent loading and release behaviors in the simulated gastrointestinal tract environments. After oral administration of the microspheres in db/db mice, maximum plasma concentration of exenatide appeared at 4 hours, and blood glucose was effectively reduced to a normal level within 2 hours and maintained for another 4 hours. The bioavailability of the exenatide-loaded microspheres, relative to subcutaneous injection of exenatide, reached 10.2%. Collectively, the present study demonstrated the feasibility of orally delivering exenatide with the new cross-linked biomaterial and formulation, and showed therapeutic potential for clinical applications.

An analysis of OSHA inspections assessing contaminant exposures in general medical and surgical hospitals.

This study analyzed data from the Occupational Safety and Health Administration's (OSHA) Chemical Exposure Health Database to assess contaminant exposures in general medical and surgical hospitals. Seventy-five inspections conducted in these hospitals from 2005 through 2009 were identified. Five categories of inspections were conducted, the three most common being complaint-based, planned, and referral-based inspections. Complaint-based inspections comprised the majority of inspections-55 (73%) of the 75 conducted. The overall violation rate for all inspection types was 68%. This finding was compared to the violation rates of planned inspections (100%), referral-based inspections (83%), and complaint-based inspections (62%). Asbestos was the hazardous substance most commonly sampled and cited by OSHA in hospitals, with 127 samples collected during 24 inspections; 31% of the total 75 inspections resulting in one or more violations were due to asbestos.

Mechanical, physical, antioxidant, and antimicrobial properties of gelatin films incorporated with thymol for potential use as nano wound dressing.

UNLABELLED: The aim of this study was to determine the properties of gelatin films incorporated with thymol. Gelatin films were prepared from gelatin solutions (10% w/v) containing thymol (1, 2, 4, and 8% w/w), glycerol (25% w/w) as plasticizer, and glutaraldehyde (2% w/w) as cross-linker. Cross-likened films showed higher tensile strength, higher elongation at break, lower Young's modulus, lower water solubility, lower swelling, lower water uptake, and lower water vapor permeability. Incorporation of thymol caused a significant decrease in tensile strength, increase in elongation at break, decrease in Young's modulus, increase in water solubility, decrease in swelling and water uptake, and increase in water vapor permeability slightly. The films incorporated with thymol exhibited excellent antioxidant and antibacterial properties. The antibacterial activity of the films containing thymol was greatest against Staphylucoccus aureus followed by Bacillus subtilis followed by Escherichia coli and then by Pseudomonas aeruginosa. Thus, gelatin films-containing thymol can be used as safe and effective source of natural antioxidant and antimicrobial agents with the purpose of evaluating their potential use as modern nano wound dressing. PRACTICAL APPLICATION: This study clearly demonstrates the potential of gelatin films incorporated with thymol as natural antioxidant and antimicrobial nano film. Such antimicrobial films exhibited excellent mechanical, physical, and water activities and could be used as antibacterial nano wound dressing against wounds burn pathogens.

Reductive amination of glutaraldehyde 2,4-dinitrophenylhydrazone using 2-picoline borane and high-performance liquid chromatographic analysis.

A typical method for the measurement of glutaraldehyde (GLA) employs 2,4-dinitrophenylhydrazine (DNPH) to form GLA-DNPhydrazone derivatives. However, this method is subject to analytical errors because GLA-DNPhydrazone is a quaternary bis-derivative and forms three geometric isomers (E-E, E-Z and Z-Z) as a result of the two C[double bond, length as m-dash]N double bonds. To overcome this issue, a method for transforming the C[double bond, length as m-dash]N double bond into a C-N single bond, using reductive amination of DNPhydrazone derivatives, has been applied. The amination reaction of GLA-DNPhydrazones with 2-picoline borane is accelerated with catalytic amounts of acid and is completed within 10 minutes in the presence of 100 mmol L(-1) phosphoric acid. Reduction of GLA-DNPhydrazone by 2-picoline borane is unique and results in the formation of N-(2,4-dinitrophenyl)-1-piperidinamine (DNPPA). NMR and LC-APCI-MS data confirmed the product identification. DNPPA is very stable and did not change when stored for at least four weeks at room temperature. DNPPA has excellent solubility of 14.6 g L(-1) at 20 °C in acetonitrile. The absorption maximum wavelength and the molar absorptivity of DNPPA were 351 nm and 4.2 × 10(4) L mol(-1) cm(-1) respectively. Complete separation between the reduced forms of C1-C10 aldehyde DNPhydrazones, including DNPPA, can be achieved by operating the reversed-phase high-performance liquid chromatograph at 351 nm in gradient mode using a C18 amide column. The reductive amination method for GLA overcomes analytical errors caused by E-E, E-Z and Z-Z geometrical isomers.

Detección de glutaraldehído en tubos anestésicos dentales mediante espectrofotometría UV-VIS / Detection of gluteraldehyde in dental anesthetics tubes using UV-Vis spectrophotometry

El proceso de esterilización de tubos anestésicos se realiza mediante una solución de glutaraldehído activado al 2 por ciento, pero el émbolo o la membrana de goma del tubo anestésico puede permitir una difusión del compuesto esterilizante. El objetivo del estudio es detectar la presencia de glutaraldehído dentro de tubos anestésicos después de aplicar protocolo de esterilización en frío (Normas de Desinfección MINSAL, 2008) mediante espectroscopía de absorción molecular. Al someter los tubos de anestésico al protocolo de esterilización podemos observar que existe una interacción entre el anestésico y la solución esterilizadora de glutaraldehído activado al 2 por ciento, entre los 220 y 250 nm, además se observa una laxitud en la membrana semipermeable después de la exposición por 10 horas al agente esterilizante. El glutaraldehído activado al 2 por ciento toma contacto con el anestésico mediante su filtración por el émbolo o diafragma.

The sterilization process is performed anesthetic tube with a solution of 2 percent activated gluteraldehyde, but the piston or diaphragm anesthetic tube allows a diffusion of sterilizing compound. The objective of this study is to detect the presence of gluteraldehyde into tubes after applying anesthetic cold sterilization protocol (Normas de Desinfección MINSAL) by molecular absorption spectroscopy. By making the pipes of anesthetic to the sterilization protocol we see that there is an interaction between the anesthetic and sterilizing solution of gluteraldehyde to 2 percent , between 220 and 250 nm, in addition there is a laxity in the semipermeable membrane after exposure for 10 hours a sterilizing agent. The activated 2 percent gluteraldehyde made contact with the anesthetic through its filtration by the piston or diaphragm.

Morfología de la lámina aracnoidea espinal humana. Barrera que limita la permeabilidad del saco dural / Structure of the arachnoid layer of the human spinal meninges: a barrier that regulates dural sac permeability

OBJETIVOS: Se ha demostrado que las moléculas inyectadas en el espacio epidural pasan desde éste al espacio subaracnoideo por difusión simple a través de la pared del saco dural. Nuestro objetivo fue estudiar la ultraestructura de células de la lámina aracnoidea y tipo de uniones especializadas responsables del efecto barrera que gobierna el tránsito de moléculas a través del saco dural humano. MATERIAL Y MÉTODO: Se estudiaron catorce muestras de la lámina aracnoidea obtenidas de dos pacientes durante intervenciones con apertura del saco dural lumbar. Las muestras se trataron con glutaraldehido, tetróxido de osmio, ferrocianuro, acetona, e incluyeron en resina. Los cortes ultrafinos se contrastaron con citrato de plomo, para poder ser observados con un microscopio electrónico de transmisión. RESULTADOS: La lámina aracnoidea posee un espesor de 35-40 μm. En su porción externa se hallan células neuroteliales del compartimento subdural, mientras que su porción interna está formada por un plano celular de 5-8 μm de espesor, constituido por la superposición de 4-5 células aracnoideas que forman la capa barrera. El espacio intercelular de este plano fue de 0,02-0,03 μm. Entre las células aracnoideas se encontraron uniones especializadas de membrana de tipo desmosomas y uniones estrechas. CONCLUSIONES: Las células aracnoideas poseen características estructurales que aseguran la función barrera del saco dural humano y no ocupan todo el espesor de la lámina aracnoidea, sólo su porción interna. La presencia de uniones especializadas de membrana entre sus células justifica la permeabilidad selectiva de esta lámina(AU)

OBJETIVES: Drugs injected into the epidural space are known to penetrate the subarachnoid space by simple diffusion through the dural sac. We aimed to study the cellular ultrastructure of the arachnoid membrane and the type of intercellular junctions responsible for creating the barrier that regulates the passage of drugs through the dural sac in humans. MATERIAL AND METHODS: Fourteen tissue samples of arachnoid membrane were taken from 2 patients during procedures that required opening the lumbar dural sac. The samples were treated with glutaraldehyde, osmium tetroxide, ferrocyanide and acetone, and then embedded in resin. Ultrathin sections were stained with lead citrate for examination by transmission electron microscopy. RESULTS: The arachnoid membrane was 35 to 40 μm thick. The outer surface contained neurothelial cells (dural border cells) along the subdural compartment, while the internal portion was made up of a plane 5 to 8 μm thick with 4 to 5 arachnoid cells overlapping to form a barrier layer. The intercellular spaces on this plane were 0.02 to 0.03 μm wide; the arachnoid cells were bridged by specialized junctions (desmosomes and other tight junctions). CONCLUSIONS: Structural features of the arachnoid cells provide a barrier within the human dural sac. They occupy only the internal portion of the arachnoid membrane. Specialized intercellular junctions explain the selective permeability of this membrane(AU)

A new effect residual ratio (ERR) method for the validation of the concentration addition and independent action models.

BACKGROUND, AIM, AND SCOPE: Glutaraldehyde (GA) often acts as an effective sterilant, disinfectant, and preservative in chemical products. It was found that GA had clearly acute toxicity to aquatic organisms. Furthermore, GA in natural environment could not exist as single species but as complex mixtures. To explore the toxicity interaction between GA and the other environmental pollutant, it is necessary to determine the mixture toxicities of various binary mixtures including GA. Two reference models, concentration addition (CA) and independent action (IA), are often employed to evaluate the mixture toxicity, which can be finished by comparing the concentration-response curves (CRCs) predicted by the reference models with the experimental CRC of the mixture. However, the CRC-based method cannot effectively denote the degree of the deviations from the reference models, especially at very low effect levels. Though the model deviation ratio (MDR) can be used to quantitatively evaluate the deviation of a mixture at EC50 level from the reference model, it is difficult to evaluate the deviations at the lower effect levels. Therefore, the primary aim of this study was to develop a new effect residual ratio (ERR) method to validate the deviations from the reference models at various effect levels. MATERIALS AND METHODS: Four chemicals having possible dissimilar mode of actions with GA, acetonitrile (ACN), dodine (DOD), simetryn (SIM), and metham sodium (MET), were selected as another component in the binary mixtures including GA, which constructed four binary mixtures, GA-ACN, GA-DOD, GA-SIM, and GA-MET ones. For each binary mixture, two equipotent mixture rays where the concentration ratios of GA to another mixture component are respectively EC50 and EC5 ones were designed and their toxicities (expressed as a percent inhibition to Photobacterium phosphoreum) were determined by microplate toxicity analysis. The observed concentration-response curve (CRC) of a ray was compared with that predicted by CA or IA model to qualitatively assess the toxicity interaction of the mixture ray. To quantitatively and effectively examine the deviations at various effect levels from the reference models, a new concept, ERR at an effect, was defined, and the ERR was employed to evaluate the deviation at various effects with confidence intervals. RESULTS: For three binary mixtures, GA-ACN, GA-DOD, and GA-SIM, the CRCs predicted by IA models were almost located in the 95% confidence intervals of the experimental CRCs for both equipotent mixture rays, which indicated the independent actions between binary mixture components. However, two rays of GA-MET binary mixture displayed a little synergistic action because both CRCs predicted by CA and IA were lower than the experimental CRC. ERR showed the same results as MDR, but ERR results at low effect area were clearer than MDR ones. DISCUSSION: In CRC comparison, the deviation of CA (for GA-ACN, GA-DOD, and GA-SIM combinations) or IA (for GA-MET) model from the experimental values could be obviously observed at medium area of the CRC. However, at very low effect levels, both deviations of CA and IA and difference between CA and IA model predictions were not very apparent. Thus, it was difficult to confirm which model, CA or IA, had better predicted power at very low effect levels. MDR in many literatures often refers to a ratio at EC50 level. It was also difficult to reflect not only the deviation fact at the other ECx but also the deviation uncertainty. After we extended the definition of MDR to all ECx and examined the 95% confidence intervals based on observation, the plot of the redefined MDRs at many effect levels could better explain the deviations of CA or IA model from the observation. However, MDRs at very low effect levels did not still reflect the high uncertainty there. The ERRs defined in our paper could explicitly explain the degree of deviation from the reference models and especially reflect the high uncertainty at very low effects. It could be said that the ERR is a better indicator than MDR. CONCLUSIONS: The new ERR validation method developed in our laboratory could provide us with the information about the toxicity interaction between the mixture components and quantitatively assess the accuracy of the reference models (CA or IA) at whole effect levels. The ERR method conquered the invalidation of the classical CRC comparison method on the deviation decision at low effect levels and also got the advantage over the MDR methods. RECOMMENDATIONS AND PERSPECTIVES: It holds promise to become an effective method of hazard and risk assessments of chemical mixtures by well characterizing the uncertainty at very low effect levels.

The use of aldehyde indicators to determine glutaraldehyde and alkaline glutaraldehyde contamination in chemical protective gloves.

The aim of this study was to assess the use of aldehyde indicator pads for detection of glutaraldehyde and alkaline glutaraldehyde permeation through chemical protective gloves under simulated in-use conditions. The quantitative analysis of glutaraldehyde permeation through a glove material was determined for Metricide, Wavicide, and 50% glutaraldehyde following a solvent-desorption process and gas chromatographic analysis. All glutaraldehyde solutions exhibited >99% adsorption (including both the glutaraldehyde oligomers of the reaction product and the excess glutaraldehyde) on the pads over the spiking range 0.05-5.0 microL. Breakthrough times for protective gloves were determined using the Thermo-Hand test method, and found to range from 76 to 150, from 170 to 230, and from 232 to 300 min for Metricide, Wavicide, and 50% glutaraldehyde, respectively. Glutaraldehyde recovery was calculated and ranged from 61 to 80% for all glutaraldehyde solutions. The mass of glutaraldehyde in these solutions at the time of breakthrough detection ranged from 17 to 18, from 18 to 19, and from 19 to 20 microg/cm(2) for Wavicide, 50% glutaraldehyde solution, and Metricide, respectively. Aldehyde indicator pads and the Thermo-Hand test method together should find utility in detecting, collecting, and quantitatively analyzing glutaraldehyde permeation samples through chemical protective gloves under simulated in-use conditions.

Investigation of non-nucleophilic additives for the reduction of morphological anomalies in protein arrays.

Uniform spot morphology is of critical importance in the fabrication and successful use of protein arrays, and solution additives are often needed to ensure good spot quality. Whereas hydroxyl-bearing molecules such as glycerol have found wide use, in our experience these reduce the efficiency of probe immobilization (particularly in the context of aldehyde-terminated surfaces). Here, we report a series of non-nucleophilic molecules that can be used as additives to improve spot homogeneity in protein arrays. Arrayed imaging reflectometry, a label-free optical biosensing technique, has been used along with spectroscopic ellipsometry to test the spot homogeneity, antibody immobilization efficiency, and activity of antihuman IgG arrays prepared with these non-nucleophilic additives on glutaraldehyde surfaces. It has been determined that 0.1% v/v 12-crown-4 performs optimally in MPBS buffer.

Infecção por micobactéria após videoartroscopia: o glutaraldeído pode ser o culpado? Estudo experimental in vitro / Mycobacterial Infection after videoarthroscopy: could glutaraldehyde be the culprit? An in vitro experimental study

OBJETIVO: Os autores avaliaram in vitro o poder de degermação do glutaraldeído a 2,2 por cento por 30 minutos, nas lâminas de shaver de 3,2mm de diâmetro, usadas em videoartroscopias. MÉTODOS: Foram utilizadas 40 lâminas, de 3,2mm, subdivididas em quatro grupos. Grupo I: 10 lâminas esterilizadas em óxido de etileno foram colocadas de forma estéril no meio de cultura Brain-heart infusion (BHI). Grupo II: 10 lâminas esterilizadas em óxido de etileno foram deliberadamente contaminadas pelas bactérias Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Streptococcus faecalis e Mycobacterium fortuitum e posteriormente colocadas no meio de cultura BHI. Grupo III: 10 lâminas esterilizadas em óxido de etileno foram contaminadas pelas mesmas bactérias e posteriormente imersas por 30 minutos em glutaraldeído e, após limpeza com soro fisiológico, colocadas no meio de cultura. Grupo IV: 10 lâminas esterilizadas em óxido de etileno foram utilizadas em artroscopias, posteriormente lavadas e imersas em glutaraldeído, também colocadas em meio de cultura. Nos meios onde houve crescimento bacteriano, este foi verificado em 72 horas de incubação, sendo esse tempo prolongado para sete dias para recuperação da micobactéria. RESULTADOS: Não houve crescimento de germes nos meios de cultura dos grupos I, III e IV, mas houve crescimento em todas as amostras do grupo II. CONCLUSÃO: A solução de glutaraldeído a 2,2 por cento, dentro do prazo de validade, utilizada por 30 minutos, mostrou-se eficaz, in vitro, na degermação de lâminas de shaver de 3,2mm de diâmetro, mesmo quando deliberadamente contaminadas por micobactéria de crescimento rápido.

OBJECTIVE: The authors made an in vitro assessment of the degermation power of 2.2 percent glutaraldehyde for 30 minutes in 3.2 mm diameter shaver blades used in videoarthroscopy. METHODS: 40 3.2 mm blades were used after being subdivided into four groups: Group I - 10 blades sterilized with ethylene oxide were placed in sterile state in a Brain-heart infusion (BHI) culture medium; Group II - ten blades sterilized with ethylene oxide were deliberately contaminated with Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Streptococcus faecalis, and Mycobacterium fortuitum and later placed in a BHI culture medium; Group III - 10 blades sterilized with ethylene oxide were contaminated by the same bacteria and later immersed in glutaraldehyde for 30 minutes, and after they were cleaned with saline solution, they were placed in the culture medium; Group IV - 10 blades sterilized with ethylene oxide were used in arthroscopic procedures , then washed an immersed in glutaraldehyde, and also placed in the culture medium. In the media were bacterial growth did occur, such growth was seen within 72 hours of incubation, such period being extended to seven days to retrieve mycobacteria. RESULTS: There was no germ growth in the culture media of Groups I, III, and IV, but bacteria grew in all samples of Group II. CONCLUSION: The 2.2 percent glutaraldehyde solution, within the validity period, used for 30 minutes, showed to be effective "in vitro", in the degermation of 3.2 mm Shaver blades even when they were deliberately contaminated by fast-growing mycobacteria.

Evaluation of environmental contamination by glutaraldehyde in an outpatient facility for digestive endoscopy in an Italian hospital.

The potential harmful effects of glutaraldehyde on human health are well known, and in recent years various new substitutes for this compound have been proposed for the disinfection and thorough sterilization of medical instruments. Nevertheless, glutaraldehyde is still widely used in hospital environments. In order to evaluate environmental contamination by glutaraldehyde vapours, the rooms of a hospital out-patient department of digestive endoscopy were monitored in 2005; a total of 52 samples were taken. The mean environmental concentration of glutaraldehyde was 3.7+/-7.4 microg/m(3). The number of efficacious air exchanges per hour was 6.3 v/h in all of the environments monitored. The study revealed that, in a hospital setting, adequate structural and functional planning, combined with responsible management on the part of the personnel and constant careful checking of the results obtained can minimize the risk of occupational exposure to glutaraldehyde.

Analytical characterisation of glutardialdehyde cross-linking products in gelatine-gum arabic complex coacervates.

Encapsulates having shells of cross-linked mixtures of proteins and polysaccharides are widely used in the food and pharmaceutical industry for controlled release of actives and flavour compounds. In order to be able to predict the behaviour and the release characteristics of the microcapsules, a better understanding of the nature and extent of the cross-linking reaction is needed. Several analytical techniques were applied for the characterisation of glutardialdehyde (GDA) cross-linked encapsulates made of gelatine and gum arabic. To allow the use of sensitive, high-resolution methods such as chromatography and mass spectrometry, the sample first had to be hydrolysed. In this way, a mixture of amino acids, small peptides and the cross-link moieties was obtained. High-resolution liquid chromatography coupled to high-resolution mass spectrometry (HPLC-MS) was applied to detect possible cross-link markers through a comparison of HPLC-MS mass-chromatograms obtained for cross-linked and non-cross-linked coacervates. HPLC-MS/MS was used to identify the species responsible for the differences. Cross-linking occurred between GDA molecules and lysine and hydroxylysine epsilon-amino groups, and up to eight cross-link products of different nature could be identified. They included pyridinium ions and Schiff bases, and also unreacted GDA condensation products. Next, based on the insight gained in the possible chemical structures present in the cross-link markers, methods for selective labelling of these functionalities were employed to allow easier detection of related reaction products. Both liquid chromatography (LC) and gas chromatography (GC) were used in these experiments. Unfortunately, these approaches failed to detect new cross-link markers, most likely as a result of the low levels at which these are present.

The effect of work practices on personal exposure to glutaraldehyde among health care workers.

Glutaraldehyde is a potential sensitizer and has been implicated in the literature as a cause of respiratory irritation and asthma among health care workers. In order to evaluate the effect of work practices and general ventilation system on employees' peak exposure to glutaraldehyde, 42 breathing zone personal air samples were taken in five hospitals. In addition, work practices were observed and recorded during the course of sampling and were classified into three categories. Presence of local or general ventilation system, air change per hour, and quantity of glutaraldehyde used were also recorded. Geometric mean concentration of all samples was 0.025 ppm (GSD=3.05). Statistical analysis indicated that work practice was the most important factor affecting the level of exposure to glutaraldehyde. In locations where "poor" or "unsafe" work practices were employed, the geometric mean concentrations were much higher (GM=0.05, GSD=2.11 and GM 0.08, GSD=1.52, respectively). The result has indicated higher prevalence of headache and itchy eyes among employees who worked where unsafe work practices were observed. Employing proper work practices can significantly reduce exposure to glutaraldehyde among health care workers. It has been recently proposed that the current occupational exposure limit of 0.2 ppm shall be reduced to either 0.1 or 0.05 ppm in the province of Québec (Canada). In this case, it is likely that concentration levels higher than these levels be experienced in some workplaces. Therefore, it is imperative that employers initiate necessary corrective action immediately.

Glutaraldehyde exposures among workers making bioprosthetic heart valves.

Exposure to glutaraldehyde is a recognized cause of work-related asthma. An investigation was undertaken to describe exposure to glutaraldehyde among workers making bioprosthetic heart valves and to make recommendations for prevention. At the two largest heart valve manufacturing facilities in California, the work process was observed; employer representatives and glutaraldehyde-exposed workers were interviewed; and employer written records, including company-generated industrial hygiene data, were analyzed. Approximately 600 female workers had continuous airborne exposure to glutaraldehyde over the course of every work shift and the routine potential for skin and eye contact with glutaraldehyde while making heart valves. Employee short-term (15-min) glutaraldehyde exposures were all well below the current regulatory ceiling level (0.20 ppm). Overall, approximately 40% of the glutaraldehyde-related job tasks involved exposures above the American Conference of Industrial Hygienists threshold limit value ceiling of 0.05 ppm; the majority (71.4% and 83.3%, depending on the company) involved exposures greater than 0.015 ppm. At one company, two cases of physician-diagnosed asthma were recorded by the employer in the previous 5-year period; these reports met the surveillance case definition for new-onset, work-related asthma associated with a known asthma inducer. Factors that contributed to worker exposure included large exposed surface areas of glutaraldehyde under agitation; working with glutaraldehyde-treated tissue in proximity to workers' breathing zones; manual pouring and disposal of glutaraldehyde solutions without local exhaust ventilation, eye protection, and waste neutralization; and prolonged use of latex gloves. Workers making bioprosthetic heart valves are at risk for occupationally acquired asthma. Employers should implement additional engineering controls to minimize workers' exposures to at least below a level of 0.015 ppm, an appropriate glove to prevent workers' skin exposure to glutaraldehyde, consistent and universal use of eye protection, and a medical surveillance program for glutaraldehyde-exposed workers.