1N Sodium Hydroxide Research Articles

Design, Synthesis, Characterisation, and Evaluation of Substituted Quinolin-2-one Derivatives as Possible Anti-lung Cancer Agents.

According to 2022, the estimated number of cancer cases in India was found to be 1,461,427. Lung cancers are the leading cause of death among Indian males. Research on cancer has been conducted to develop better treatments that are safe and effective and could be used to diagnose cancer at an early stage. It was found that quinolin-2-one possesses anticancer activity, which led us to synthesize substituted quinolin-2-one derivatives that can provide a longer future to cancer patients and decrease the risk of dying from cancer. This study aimed to carry out the design, synthesis, characterisation, and evaluation of novel substituted quinolin-2-one analogues as possible anti-lung cancer agents. Compound III a/III b on reaction with acids, sodium acetate and ethylchloroacetate, substituted benzaldehyde, phthalic anhydride, and 2N sodium hydroxide yielded compounds IV a/ IV b, V a/ V b, VI a/ VI b, VI c/ VI d, VI e/ VI f, VII a/ VII b, and VIII a/ VIII b, respectively. Among all the synthesised derivatives, compound VII a was found to be most potent with a MolDock score of -132.78 as compared to standard drug imatinib (-114.37) and active ligand 4- anilinoquinazoline (-126.71). All the synthesized derivatives showed a good ADME profile, but compound VII a showed the best ADME data among all the synthesised derivatives. All the synthesised compounds were tested for their in vitro anticancer activity against the Hop-62 (human lung cancer) cell line, out of which compound VII a was found to be most potent, with a percent control growth of -51.7% at a concentration of 80 μg/ml, which was in comparable to the positive control, Adriamycin (-70.5%) and standard imatinib (-84.0%). Compound VII a showed the highest MolDock score and was most potent against human lung cancer cell line Hop-62.

Corrosion resistance of Aluminium steel in 1N Sodium Hydroxide solution by an aqueous extract of Thespesia populnea plant leaves

Corrosion resistance effect of aluminium steel in 1N sodium hydroxide by an aqueous extract of Thespesia populnea plant leaves has been investigated by mass loss method. It is observed that as the concentration of the inhibitor increases, the inhibition efficiency increases. The mechanistic aspects of corrosion resistance have been studied by potentiodynamic polarization technique and electrochemical impedance spectroscopy. A maximum inhibition efficiency of 78.70% is achieved by this inhibitor system. Potentiodynamic polarization technique reveals that the inhibitor system functions as a mixed type of inhibitor, controlling anodic and cathodic reactions. It is noted that in the presence of inhibitor, linear polarization resistance value increases and corrosion current decreases. Electrochemical impedance studies reveal that a protective film is formed on the Al steel surface, since in the presence of inhibitor system, the charge transfer resistance value increases and double layer capacitance value decreases. This is due to adsorption of the molecules of the active ingredients of the extract on the Al steel surface. The inhibition efficiency increases due to adsorption of hetero atoms present in TP plant leaves extract on the Al steel surface. The maximum inhibition efficiency and the lower corrosion rate are obtained at high concentration 1200 ppm for TP plant leaves extract. By further increase in inhibitor concentration above 1200 ppm, the inhibition efficiency and corrosion rate almost remained constant. So, the 1200 ppm concentration is fixed as the maximum inhibition for the investigative aqueous extract of plant leaves as corrosion inhibitor. This concentration corresponds to the attainment of a saturation value in surface coverage of Al steel. The protective film formed over the Al steel surface has been characterized by Fourier Transform infra-red spectroscopy. The surface morphology of the protective film of carbon steel immersed in sodium hydroxide in the absence and presence of inhibitor has been studied by Scanning electron microscopy. The outcome of the study can be used in pickling industry wherein sodium hydroxide is used to remove the rust on the Al steel surface.

Topical Losartan and Corticosteroid Additively Inhibit Corneal Stromal Myofibroblast Generation and Scarring Fibrosis After Alkali Burn Injury.

PurposeTo evaluate the efficacy of losartan and prednisolone acetate in inhibiting corneal scarring fibrosis after alkali burn injury in rabbits.MethodsSixteen New Zealand White rabbits were included. Alkali injuries were produced using 1N sodium hydroxide on a 5-mm diameter Whatman #1 filter paper for 1 minute. Four corneas in each group were treated six times per day for 1 month with 50 µL of (1) 0.2 mg/mL losartan in balanced salt solution (BSS), (2) 1% prednisolone acetate, (3) combined 0.2 mg/mL losartan and 1% prednisolone acetate, or (4) BSS. Area of opacity and total opacity were analyzed in standardized slit-lamp photos with ImageJ. Corneas in both groups were cryofixed in Optimal cutting temperature (OCT) compound at 1 month after surgery, and immunohistochemistry was performed for alpha-smooth muscle actin (α-SMA) and keratocan or transforming growth factor β1 and collagen type IV with ImageJ quantitation.ResultsCombined topical losartan and prednisolone acetate significantly decreased slit-lamp opacity area and intensity, as well as decreased stromal myofibroblast α-SMA area and intensity of staining per section and confined myofibroblasts to only the posterior stroma with repopulation of the anterior and mid-stroma with keratocan-positive keratocytes after 1 month of treatment. Corneal fibroblasts produced collagen type IV not associated with basement membranes, and this production was decreased by topical losartan.ConclusionsCombined topical losartan and prednisolone acetate decreased myofibroblast-associated fibrosis after corneal alkali burns that produced full-thickness injury, including corneal endothelial damage. Increased dosages and duration of treatment may further decrease scarring fibrosis.Translational RelevanceTopical losartan and prednisolone acetate decrease myofibroblast-mediated scarring fibrosis after corneal injury.

Chemical Processes in PEO Coatings Formation and Destruction on Titanium Alloy VT-1

Plasma electrolytic oxidation (PEO) method allows obtaining multifunctional ceramic-like coatings with unique properties. This article examines the relevant problem of the electrolyte effect on the chemical composition of PEO coating. The corrosion resistance of titanium alloy various PEO coatings in corrosive liquids has been studied: 1N sodium hydroxide solution, concentrated sulphuric acid (80%), 1N sulphuric acid solution, concentrated hydrochloric acid (30%), 1N hydrochloric acid solution. Comparative analysis of the VT-1 titanium alloy chemical resistance showed that the most resistant to the effects of corrosive substances were samples with PEO coating formed in a hydrophosphate electrolyte Na2HPO4.

PEMBUATAN DAN UJI PEMBAKARAN ETHANOL GEL

Semi-solidification of ethanol solution as fuel for heating process in communities will improve safety, because gel phase will not spread when it’s spilled. For this purpose, gelling agent that has good interaction with ethanol solution is needed. Carbopol ((C3H4O2)n) is a good gelling agent for water-based solution. The suitable concentration of carbopol as gelling agent in the solution is in the range of 0,5-2,0%w with pH of mixture is in the range of 5–7. Aims of this study were to understand the process of ethanol gel production and to observe the effect of addition different amount of carbopol to physical characteristic of the gel. Water heating test was also done in order to find the optimum chemicals composition. Ethanol gel was made by slowly adding the certain amount of carbopol (0.8; 1.0; 1.2; 1.4; and 1.6 gram) in 100 mL ethanol solution (70%w). After it reached homogenity (about 45 minutes), 1 mL of 1N sodium hydroxide solution was slowly added while continue stirring until the gel was formed. We found that each gel has no significant different in the physical characteristics. Ethanol gel ignition time was fast (less than 1 second) with blue-transparent flame. In this study, 5 gram of ethanol gel consumed 7.2–8.4 minutes for complete burning and left 13–4.2%w solid residue. The measured flame temperatur were 725–751oC. Based on water heating test, the optimum value of heat absorbed (kal)/minutes/gram of ethanol gel was reached at 1.2 gram addition of carbopol.

Magnetic Solid-Phase Extraction of Drugs and Pesticides from Human Plasma Using COOH-mMWCNTs.

Carbon nanotubes (CNTs) are useful for extracting chemical compounds due to their properties, such as surface area and the potential for chemical modification. Especially the formation of CNTs with carboxylic acid functional group makes them disperse in water-based samples and have strong interaction forces with cationizable analytes. Based on these features, carboxylic acid functionalized multi-walled CNTs (COOH-MWCNTs) have been used as extraction sorbents. CNT can also be gathered using an external magnet by forming complex with iron oxide (Fe3O4) magnetic nanoparticles (MNPs). In this study, COOH-MWCNTs with MNPs were subjected to magnetic solid-phase extraction (mSPE) in order to extract the targeted substances such as diphenhydramine, doxylamine, tramadol, escitalopram, zolpidem, diphenamid, paclobutrazol, hexaconazole, cyproconazole and mepronil from human plasma samples. The following five factors were optimized: (i) the ratio of COOH-MWCNTs to MNPs as a sorbent from 1:1 to 1:4; (ii) sorbent amount starting from 12.5 to 75%; (iii) sample pH tested pH2 to pH10 with 1N hydrochloride and 1N sodium hydroxide; (iv) agitating time from 0 to 4min and (v) elution solvent. Limit of detection of 10 targeted substances in human plasma were in the range of 0.1-0.4mg/L. The recovery of targeted substances (except diphenamid) in human plasma was 73.06-110.28% for intra-day and 83.00-107.70% for inter-day and the precision (relative standard deviation, %) in human plasma was 0.3-13.3% for intra-day and 2.9-15.6% for inter-day. The method was applied to nine authentic biological samples from overdose patients in the emergency room of Chungnam National University Hospital. The performance of mSPE was compared with the liquid-liquid extraction method using ethyl acetate. The results showed that the newly developed method in this study can be used for screening analysis in forensic and clinical toxicology.

Utilization of Jengkol Peel (Pithecellobium jiringa (Jack) Prain) as Lead (II) Ions Bio-sorbent with Column Method

Problems arising from laboratory waste include the content of lead metal ions in it, which can affect health. While on the other hand, Jengkol peel is a market waste and has no economic value. Jengkol peel contains hydroxyl groups and carboxylates to bind heavy metals such as lead (II) ions. So, this study aims to determine the effect of variations in flow rate, adsorbent height, and solution acidity and determine the ability of Jengkol peel in adsorbing lead (II) ions in the laboratory liquid by the column method. Organic groups that include active sides can be removed using 1N sodium hydroxide to increase the adsorption ability. Sodium hydroxide functions to dissolve lignin in lignocellulose compounds so that carboxylic groups are formed in cellulose, which has a role in binding metal ions. The determination of functional groups was carried out by Fourier-transform Infrared Spectroscopy. The identification of the adsorbent morphology was carried out by Scanning Electron Microscope. The adsorption of lead (II) ions by Jengkol peel was determined by calculating the difference between the lead (II) ions in the solution after and before passing through the column. The amount of lead metal remaining in solution was determined using Atomic Absorption Spectroscopy. Sodium hydroxide solution with a concentration of 1N can separate lignin from cellulose contained in lignocellulose to enhance the bio-sorbent ability of the Jengkol peel in binding metal ions. The smaller the flow rate in the column, the higher the amount of lead (II) ions adsorbed in the bio-sorbent. The acidity of the solution has the best adsorption at pH 5. The metal ions from the simulation sample can reduce the number of lead (II) metal ions adsorbed by 11%.

Application of sol–gel technique for preparation of nanosilica from coal powered thermal power plant fly ash

Fly ash, a thermal power plant by-product is increasing and it is expected that this by-product will increase with increase in energy demand, especially in developing countries. Considering this, current study presents a novel process for the utilization of thermal power plant waste i.e., (fly ash) by fractionating it into silica particles and aluminum enriched residual ash. Fractionation of fly ash helped to extract industrial grade pure form of nanosilica. As a first step fly ash was added into 2N Sodium hydroxide solution, and resulting suspension was autoclaved for 120 min duration at 100 °C. After filtration, supernatant was collected and 1N HCl was added drop-wise, allowing precipitation of silica in the solution. A white cloudy gel-like precipitate of silica was formed which was filtered and washed several times to remove the impurities of Na, K, and chloride salts. This procedure yielded the nanosilica a final product, which was characterized for crystalline index and composition by using X-ray diffraction and fluorescence technique. The result of X-ray diffraction shows a broad hump in the region of 20°–22° indicating amorphous nature of the product was studied using field emission scanning electron microscopic and transmission electron microscopic analytical technique was used to study about internal structure, morphological features and size of the molecules which depicts spherical globular silica particles in 10–40 nm range. Further, chemical bonds were studied by infrared analysis (fourier transform infrared) and results indicated the presence of silica oxygen bonding (–Si–O–Si–) at 785 cm−1 and Si–OH bonds 3000–3500 cm−1. Energy dispersive X-ray analysis shows the presence of silicon and oxygen elements, which forms 99.9% of prepared nanosilica particles by weight.

Biosorptive uptake of Fe2+, Cu2+ and As5+ by activated biochar derived from Colocasia esculenta: Isotherm, kinetics, thermodynamics, and cost estimation

The adsorptive capability of superheated steam activated biochar (SSAB) produced from Colocasia esculenta was investigated for removal of Cu2+, Fe2+ and As5+ from simulated coal mine wastewater. SSAB was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller analyser. Adsorption isotherm indicated monolayer adsorption which fitted best in Langmuir isotherm model. Thermodynamic study suggested the removal process to be exothermic, feasible and spontaneous in nature. Adsorption of Fe2+, Cu2+ and As5+ on to SSAB was found to be governed by pseudo-second order kinetic model. Efficacy of SSAB in terms of metal desorption, regeneration and reusability for multiple cycles was studied. Regeneration of metal desorbed SSAB with 1N sodium hydroxide maintained its effectiveness towards multiple metal adsorption cycles. Cost estimation of SSAB production substantiated its cost effectiveness as compared to commercially available activated carbon. Hence, SSAB could be a promising adsorbent for metal ions removal from aqueous solution.

Synthesis of chiral linear and macrocyclic candidates: VI. Synthesis and antibacterial activity of some macrocyclic tripeptides and linear dipeptide Schiff bases

A series of macrocyclic tripeptides and linear dipeptide Schiff base derivatives has been synthesized using pyridine-3,5-dicarboxylic acid and L-phenyalanine methyl ester as starting materials. Treatment of pyridine-3,5-dicarbonyl dichloride with L-phenylalanine methyl ester gave N,N′-(pyridine-3,5-diyldicarbonyl)bis(L-phenyalanine methyl ester) which was hydrolyzed with 1N sodium hydroxide to the corresponding bis-acid, and the latter was cyclized with diamino acids to afford macrocyclic tripeptide derivatives. The reaction of the bis ester with hydrazine hydrate gave bis-hydrazide, which was condensed with aldehydes to obtain the corresponding Schiff base derivatives. The structures of the newly synthesized compounds were confirmed by IR, 1H and 13C NMR, and MS spectral data and elemental analyses. The antimicrobial activities of some of the newly synthesized compounds were comparable with that of Streptomycin used as control.

Stability Indicating High Performance Liquid Chromatographic Method for The Determination of Bromazepam in the presence of its degradation products

A reversed-phase HPLC method was developed and validated for the determination of Bromazepam and its degradation products. The acidic hydrolysis of Bromazepam was carried out in 1N hydrochloric acid solution while the alkaline hydrolysis was carried out in 1N sodium hydroxide solution both at 95°C.Two degradation products were isolated and identi?ed by mass spectroscopy. Spectroscopic data indicated that (2-amino-5-bromophenyl)(pyridine-2-yl) methanone was the degradation product of this acid hydrolysis, whereas 4-bromobenzene- 1,2-diol was the degradation product of the alkaline hydrolysis. A mobile phase consisting Phosphate buffer pH 3.5 Acetonitrile (82:18 v/v) was used, and separation was done on a Zorbax Column C18 dimension 250x 4.6mm, particle size 5µ. Using A flow rate of 1 ml.min-1 while detection wavelength was 240.0nm.Retention times were 3.65, 2.60 and 1.85 for intact Bromazepam, acid and alkaline induced ion products respectively. The method showed good linearity in the concentration range of 20–100 µgmL−1. The intra- and interassay precision RSD% were 0.256 and 0.756 respectively .Statistical comparison between the results obtained for the analysis of Bromazepam in pure form and the reported HPLC method showed that values of the calculated t and F are less than the tabulated ones, which reveals that there is no significant difference between the compared methods with respect to accuracy and precision,

Mycelial Mattress from a Sporangia Formation-Delayed Mutant of Rhizopus stolonifer as Wound Healing-Enhancing Biomaterial.

A mycelial mattress of Rhizopus stolonifer obtained from a liquid static culture was utilized for wound dressing and biomedical use. Following screening of mutants induced by UV radiation, F6, exhibiting delayed sporangium formation was selected because its sporangium maturation exhibited a 5-day delay without significant loss of mycelial weight compared to the wild type. The sporangium-free mycelial mattress from the sporangiospore culture of F6 was treated with 1N sodium hydroxide NaOH at 85°C for 2 h to produce a sponge-like membrane named Rhizochitin. The trifluoroacetic acid hydrolysate of Rhizochitin contained 36% N-acetylglucosamine and 53% hexose respectively detected by the Elson-Morgen and phenol-sulfuric acid methods. Results indicated the wound area in rats covered with Rhizochitin was 40% less than that of the uncovered group. Rhizochitin decreased the expression of PDGF in the proliferation stage, increased the expression of TGF-β in the inflammation and proliferation stages, and increased the expression of VEGF in the inflammation and proliferation stages. Rhizochitin inhibited secretion of matrix metalloproteinase-9 on days 1, 7, 9, and 12 and matrix metalloproteinase-2 on days 3, 7, 9, and 12. It was concluded that Rhizochitin has beneficial properties of biocompatible, biodegradable, and wound healing.

Saccharification behavior of cellulose acetate during enzymatic processing for microbial ethanol production

This study was conducted to realize the potential application of cellulose acetate to enzymatic processing, followed by microbial ethanol fermentation. To eliminate the effect of steric hindrance of acetyl groups on the action of cellulase, cellulose acetate was subjected to deacetylation in the presence of 1N sodium hydroxide and a mixture of methanol/acetone, yielding 88.8-98.6% at 5-20% substrate loadings during a 48h saccharification at 50°C. Ethanol fermentation using Saccharomyces cerevisiae attained a high yield of 92.3% from the initial glucose concentration of 44.2g/L; however, a low saccharification yield was obtained at 35°C, decreasing efficiency during simultaneous saccharification and fermentation (SSF). Presaccharification at 50°C prior to SSF without increasing the total process time attained the ethanol titers of 19.8g/L (5% substrate), 38.0g/L (10% substrate), 55.9g/L (15% substrate), and 70.9g/L (20% substrate), which show a 12.0-16.2% improvement in ethanol yield.

Physical, chemical, and surface properties of alkali-treated Indian hemp fibers

The plant fibers are rich in cellulose and they are easily renewable source of fibers with the potential for polymer reinforcement. The presence of surface impurities and the large amount of hydroxyl groups make plant fibers less attractive for reinforcement of polymeric materials. Hemp (Cannabis sativa L.) fibers were subjected to alkalization using 1N sodium hydroxide (NaOH). The physical, chemical, and surface properties of untreated and chemically modified fibers are studied using X-ray diffraction (wide angle X-ray scattering), Fourier transform infrared spectroscopy and scanning electron microscopy (SEM), respectively. The microstructural parameters such as crystallite size 〈N〉, lattice strain (g in %), and enthalpy (α*) have been determined by X-ray line profile analysis using Fourier method of Warren. It was found that the crystallite size 〈N〉 decreases with the increase in treatment time. SEM study shows the fibers surface becoming rough and suitable for reinforcement.

Novel Spot Tests for Detecting the Presence of Zinc Sulfate in Urine, a Newly Introduced Urinary Adulterant to Invalidate Drugs of Abuse Testing

To find a suitable method for detecting zinc sulfate in adulterated urine. Two rapid spot tests to detect the presence of zinc sulfate in urine were developed. Addition of 3 to 4 drops of 1N sodium hydroxide solution to approximately 1 mL of urine containing zinc sulfate led to the formation of a white precipitate, which was soluble in excess sodium hydroxide. In the second spot test, addition of 3 to 4 drops of 1% sodium chromate solution to 1 mL of urine containing zinc sulfate followed by the addition of 4 to 5 drops of 1N sodium hydroxide led to formation of a yellow precipitate (zinc chromate). Detection limit of these visual spot tests was 10 mg/mL of zinc sulfate in urine. Twenty drug-free urine specimens and urine containing high amounts of sugar or reducing substances were tested with no false-positive spot test results observed. However, if lead is present in high amounts in urine, it may cause false-positive spot test results. When aliquots of urine controls for drugs of abuse testing were supplemented with different amounts of zinc sulfate, false-negative drug test results were observed except for amphetamine. Zinc sulfate also falsely reduced measured urine alcohol level in urine. Zinc sulfate can invalidate urine drug and alcohol testing but can be detected using the novel spot tests developed.

Chemical modification of cellulose extracted from sugarcane bagasse: Preparation of hydroxyethyl cellulose

Cellulose was extracted from sugarcane bagasse by alkaline extraction with sodium hydroxide followed by delignification/bleaching using sodium chlorite/hexamethylenetetramine system. Factors affecting extraction process, including sodium hydroxide concentration, hexamethylenetetramine concentration and temperature were studied and optimum conditions for alkaline extraction were found to be boiling finely ground bagasse under reflux in 1N sodium hydroxide solution and then carrying out the delignification/bleaching treatment at 95°C using 5g/l sodium chlorite together with 0.02g/l hexamethylenetetramine. The extracted cellulose was used in the preparation of hydroxyethyl cellulose through reaction with ethylene oxide in alkaline medium. Factors affecting the hydroxyethylation reaction, like sodium hydroxide concentration during the alkali formation step, ethylene oxide concentration, reaction temperature and reaction duration were studied. Optimum conditions for hydroxyethylation reaction were using 20% NaOH solution and 200% ethylene oxide (based on weight of cellulose), carrying out the reaction at 100°C for 60min.

Comparison of the therapeutic effects of extracts from Spirulina platensis and amnion membrane on inflammation-associated corneal neovascularization.

To compare the therapeutic effects of polysaccharide extract from Spirulina platensis (PSP) and extract from amnion membrane (AME) on alkali burn-induced corneal neovascularization (CorNV). PSP and AME were extracted from dry powder of Spirulina platensis and human aminion membrane respectively. Murine CorNV was induced by applying 1N sodiumhydroxide (NaOH) solution directly on the mice corneas. PSP and AME extracts were administered topically on the corneas 4 times daily for 7 days. The therapy effects of PSP and AME extracts were evaluated daily using slit-lamp. At the end of the therapy, corneas were harvested for H&E staining, masson trichrome staining, immunohistochemical study, and semi-quantification reverse transcriptive PCR (RT-PCR) was utilized for measurement of inflammation-related molecules. Topical application of PSP extract had significant therapeutic effects on CorNV that could be shown in various assays of the corneas. Compared with AME extract, PSP extract treatment was more effective in suppressing CorNV in terms of vessel length and levels of cluster of differentiation 31 (CD31) proteins or the angiogenesis related genes like vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9). PSP also inhibited inflammation more markedly by more effectively inhibiting mononuclear and polymorphonuclear cells infiltration into the corneal stroma and reducing levels of stromal cell-derived factor-1 (SDF1), tumor necrosis factor-alpha (TNFα) and macrophage inflammatory protein-3 (MIP3a). In additon, corneas of PSP group had a more regular and compact architecture of collagen with thinner corneal thickness than in the AME group. Polysaccharide extract from Spirulina platensis inhibited alkali burn-induced inflammation and CorNV more effectively than AME extract at the studied doses, thus may be used for the therapy of corneal diseases involving neovascularization and inflammation.

Physico-chemical characterization of an exopolysaccharide produced by a non-ropy strain of Leuconostoc sp. CFR 2181 isolated from dahi, an Indian traditional lactic fermented milk product

Exopolysaccharide (EPS) producing non-ropy strain of lactic acid bacteria (LAB) was isolated from dahi, an Indian traditional fermented milk product, and on the basis of morphology, physiological and biochemical tests it was identified as Leuconostoc sp. CFR 2181. In shake flask fermentation for 72 h at 22 °C, the quantity of EPS produced by the isolate was 13.8 g/L in modified MRS broth and 25.4 g/L in EPS medium (a newly formulated simplified synthetic medium). The EPS was non-gelling and non-film forming. It was completely soluble in water and 1N sodium hydroxide solution. The purified EPS contained 84% of total carbohydrates, 11.2% of reducing sugars, 2% of moisture, 0.8% of proteins and 0.6% uronic acid. The EPS consisted mainly of glucose (91%) with minor quantities of rhamnose and arabinose (1.8% each). Gel permeation chromatography indicated considerable heterogeneity of EPS, having three fractions with molecular weights ranging from 1.0 × 10 4 to 1.5 × 10 6 Da. Enzymatic hydrolysis with pullulanase and α-amylase and NMR analysis of the EPS indicated the presence of α (1 → 6) linkages and the absence of α (1 → 4) linkages.

Quantitative evaluation of prion inactivation comparing steam sterilization and chemical sterilants: proposed method for test standardization

Prions are notoriously resistant to inactivation. To prevent accidental transmission of variant Creutzfeldt-Jakob disease (vCJD), various decontamination procedures have been adopted for re-usable medical devices by the authorities of countries at risk. As the vCJD agent in humans has a wide tissue distribution, practical methods of prion decontamination urgently need to be standardized, as do other sterilization and disinfection procedures (European Committee for Standardization). This article proposes a method using a quantitative murine model, combining observations of the decrease in the infection rate, the increase in the incubation period and a simultaneously performed chemical protein fixation control. In terms of practical application, autoclaving at 134 degrees C for 18 min or 121 degrees C for 30 min, and 1N sodium hydroxide for 15 min reduced the transmission of infectivity by a factor of at least 10(6). Partial efficacy can also be identified by the methodology, particularly for liquid cold sterilants such as glutaraldehyde and peracetic acid solutions.

Alkali-Induced Corneal Stromal Melting Prevention by a Novel Platelet-Activating Factor Receptor Antagonist

To evaluate the effect of LAU0901 (2,4,6-trimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid ester), a novel platelet-activating factor (PAF) receptor antagonist, on a rabbit model of severe corneal alkali injury. Adult New Zealand albino rabbits were anesthetized and the right eyes were injured with 2N sodium hydroxide for 60 seconds using a 12-mm plastic well, then rinsed. After the injury, 10 rabbits were treated topically with LAU0901 every 2 hours 4 times per day and received a subconjunctival injection of 200 microL of LAU0901 once per week and 10 rabbits were treated with vehicle the same way. Over the course of 4 weeks, the corneas were examined daily by slitlamp microscopy and corneal ulcers were graded with a clinical scoring system. Ten additional rabbits were treated as described but 1 rabbit from each group was killed at 1, 3, 7, 14, or 21 days after injury. The corneas were processed for histopathologic and immunofluorescence examination. Persistent epithelial defects were present in both groups from day 5 postinjury, but from day 9 through day 25, the average clinical scores of both epithelial defects and stromal ulcerations in the vehicle-treated eyes were significantly higher than those in the LAU0901-treated eyes (P<.01). By day 28, 90% of the eyes in the vehicle-treated group perforated, while only 20% of the eyes in the LAU0901-treated group developed deep ulceration and none were perforated. Histologic examination showed that the corneas treated with LAU0901 for 4 weeks were completely reepithelialized, with fewer inflammatory polymorphonuclear leukocytes and more repair fibroblasts (myofibroblasts) in the stroma as compared with those treated with vehicle. LAU0901 inhibits corneal ulceration and perforation in a severe alkali-burn model in the rabbit. In the cornea, PAF is a strong inflammatory mediator, a chemotactic to inflammatory polymorphonuclear leukocytes, and an inducer of several proteases that degrade the extracellular matrix. Clinical Relevance The inhibition of PAF action by LAU0901 could be important in the immediate and intermediate treatment of chemical injuries to preserve the integrity of the cornea.