Natural pyrite-stimulative periodate activation: efficiency and mechanism study.

Natural pyrite (NP) is an alternative catalyst for wastewater purification via advanced oxidation processes (AOPs). However, the activation performance and mechanism of periodate (PI) by NP have not yet been revealed. Herein, this work examines the activation performance of NP towards PI and its application in the degradation of antibiotic wastewater. Interestingly, 95.69% of chlortetracycline (CTC) was degraded by NP within 20 min via PI activation. Besides, NP shows effective degradation of various pollutants such as rhodamine B (65.81%), sulfamethoxazole (89.04%), and sodium butylxanthate (99.77%) within 20 min. The active species quenching experiment suggested that the active species ∙ OH , IO 3 ∙ , 1O2 and the active complex of PI bonded with NP surface participated in CTC degradation. In addition, Fe(II) on NP surface is the main active site for PI activation, while Sn2- species accelerates the reduction of Fe(III) to Fe(II) and promotes sustained PI activation. This work provides new ideas for the application of NP in environmental pollution control.

Sustainable bioelectric activation of periodate for highly efficient micropollutant abatement.

The periodate (PI)-based advanced oxidation process is valued for environmental remediation, but current activation methods involve high costs, secondary contamination risks, and limited applicability due to external energy inputs (e.g., UV), catalyst incorporation (e.g., Fe2+), or environmental modifications (e.g., freezing). In this work, novel bioelectric activation of PI using the electrons generated by electroactive bacteria was developed and investigated for rapid removal of carbamazepine (CBZ), achieving 100 %, 100 %, and 76 % removal efficiency for 4.22 µM of CBZ in 20 min at pH 2, 120 min at pH 6.4, and HRT of 30 min at pH 8.5, respectively, with a 1 mM PI dose and without an input voltage. It was deduced that electrons derived from bacteria could directly activate PI using Ti mesh electrodes and generate •IO3 via single electron transfer under strongly acidic conditions (e.g., pH 2). Nevertheless, under weak alkaline conditions (e.g., pH 8.5), biogenic electrons indirectly activated PI by generating OH-via 4e-reduction at the Ti mesh cathode, resulting in the formation of •O2- and 1O2. In addition to the metal cathode, a carbon-based cathode finely modulates the 2e-reduction, yielding H2O2 and activating PI to mainly form •OH. Moreover, primarily non-toxic IO3- was produced during treatment, while no detectable reactive iodine species (HOI, I2, and I3-) were observed. Furthermore, the bioelectric activation of PI demonstrated its capability to remove various micropollutants present in secondary-treated municipal wastewater, showcasing its broad-spectrum degradation ability. This study introduces a novel, cost-effective, and environmentally friendly PI activation technique with promising applicability for micropollutant elimination in water treatment.

Activation of periodate by biocarbon-supported multiple modified nanoscale iron for the degradation of bisphenol A in high-temperature aqueous solution.

As reported, the persistent toxic and harmful pollutant bisphenol A (BPA) from industrial emissions has been consistently found in aquatic environments inhabited by humans. Periodate (PI)-based advanced oxidation processes (AOPs) have been employed to degrade BPA, although activating PI proves more challenging compared to other oxidants. A novel nano iron metal catalyst, sulfided nanoscale iron-nickel bimetallic nanoparticle supported on biocarbon (S-(nFe0-Ni)/BC) was synthesized and utilized to activate PI for the removal of BPA. The morphology, structure, and composition of S-(nFe0-Ni)/BC were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), and fourier-transform infrared spectrum (FTIR). The catalyst demonstrates an excellent ability to activate PI, achieving a BPA removal efficacy of 86.4%, accompanied by a 33% reduction in total organic carbon (TOC) in the {S-(nFe0-Ni)/BC}/PI system. BPA degradation exhibited a significant change at the 5-min mark. In the first stage (0-5 min), nonlinear dynamic fitting research, combined with scavenging experiments, unveiled the competitive degradation of pollutants primarily driven by iodate radical ( IO 3 · ), singlet oxygen 1 O 2 , and hydroxyl radical ( · OH ). The competitive dynamics aligned with the ExpAssoc model. The contribution rates of different active species during the second stage (5-120 min) were calculated. The contributions of main species to BPA removal follow the order of IO 3 · > 1 O 2 > · OH throughout the entire process. The influence of various parameters, such as the dosage of S-(nFe0-Ni)/BC, initial PI concentration, BPA concentration, pH, temperature, and the presence of coexisting anions, was also examined. Finally, a plausible reaction mechanism in the system is proposed, suggesting that the {S-(nFe0-Ni)/BC}/PI system involves a heterogeneous synergistic reaction occurring primarily on the surface of S-(nFe0-Ni)/BC. Therefore, this study proposes a promising approach for PI-based AOPs to degrade organic pollutants, aiming to mitigate the irreversible harm caused by such pollutants to organisms and the environment.

Simulated sunlight/periodate-triggered formation of toxic halogenated bisphenols in highly saline water.

Periodate (PI)-based oxidation using the activators, such as metal ions and light irradiation, has emerged as a feasible treatment strategy for the effective remediation of contaminated water and wastewater. Given the pervasive nature of PI residues and solar exposure during application, the role of solar light in remediating the challenging highly saline water matrices needs to be elucidated. In this study, bisphenol A (BPA) was selected as the targeted micropollutant, which can be efficiently eliminated by the simulated sunlight (SSL)/PI system in the presence of high-level Cl- (up to 846.0 mM) at pH 7.0. The presence of different background constituents of water, such as halides, nitrate, and dissolved organic matter, had no effect, or even accelerated BPA abatement. Particularly, the ubiquitous Br- or I- appreciably enhanced the BPA transformation efficiency, which may be ascribed to the generation of high-selective reactive HOBr or HOI. The in silico predictions suggested that the transformation products generated by halide-mediated SSL/PI systems via halogen substitutions showed greater persistence, bioaccumulation, and aquatic toxicity than BPA itself. These findings highlighted a widespread phenomenon during PI-based oxidative treatment of highly saline water, which needs special attention under solar light illumination.

Structural characterization of a glycoprotein from white jade snails (Achatina Fulica) and its wound healing activity.

Snail mucus is rich in proteins and polysaccharides, which has been proved to promote wound healing in mice in our previous research. The aim of this study was to investigate the effective component in snail mucus that can exert the wound healing potential and its structural characterization. Here, the glycoprotein from the snail mucus (SM1S) was obtained by DEAE-Sepharose Fast Flow and Sephacryl S-300 columns. The structural characteristics of SM1S were investigated via chromatographic techniques, periodic acid oxidation, FT-IR spectroscopy and NMR spectroscopy. Results showed that SM1S was a glycoprotein with a molecular weight of 3.8 kDa (83.23 %), consists of mannose, glucuronic acid, glucose, galactose, xylose, arabinose, fucose at a ratio of 13.180:4.875:1043.173:7.552:1:3.501:2.058. In addition, the periodic acid oxidation and NMR analysis showed that SM1S contained 1,6-glycosidic bonds, and might also contain 1 â†’ 4 and 1 â†’ 2 glycosidic or 1 â†’ 3 glycosidic bonds. Furthermore, the migration experiment of human skin fibroblasts in vitro suggested that SM1S had a good effect to accelerate the scratch healing of cells. This study suggested that SM1S may be a prospective candidate as a natural wound dressing for the development of snail mucus products.

Specialized digestive mechanism for an insect-bacterium gut symbiosis.

In Burkholderia-Riptortus symbiosis, the host bean bug Riptortus pedestris harbors Burkholderia symbionts in its symbiotic organ, M4 midgut, for use as a nutrient source. After occupying M4, excess Burkholderia symbionts are moved to the M4B region, wherein they are effectively digested and absorbed. Previous studies have shown that M4B has strong symbiont-specific antibacterial activity, which is not because of the expression of antimicrobial peptides but rather because of the expression of digestive enzymes, mainly cathepsin L protease. However, in this study, inhibition of cathepsin L activity did not reduce the bactericidal activity of M4B, indicating that there is an unknown digestive mechanism that renders specifically potent bactericidal activity against Burkholderia symbionts. Transmission electron microscopy revealed that the lumen of symbiotic M4B was filled with a fibrillar matter in contrast to the empty lumen of aposymbiotic M4B. Using chromatographic and electrophoretic analyses, we found that the bactericidal substances in M4B existed as high-molecular-weight (HMW) complexes that were resistant to protease degradation. The bactericidal HMW complexes were visualized on non-denaturing gels using protein- and polysaccharide-staining reagents, thereby indicating that the HMW complexes are composed of proteins and polysaccharides. Strongly stained M4B lumen with Periodic acid-Schiff (PAS) reagent in M4B paraffin sections confirmed HMW complexes with polysaccharide components. Furthermore, M4B smears stained with Periodic acid-Schiff revealed the presence of polysaccharide fibers. Therefore, we propose a key digestive mechanism of M4B: bacteriolytic fibers, polysaccharide fibers associated with digestive enzymes such as cathepsin L, specialized for Burkholderia symbionts in Riptortus gut symbiosis.

Highly efficient degradation of acetaminophen via nano zero-valent iron biochar with periodate system at low temperature.

The development of more efficient advanced oxidation systems for serving various advanced treatment of wastewater is quite necessary and urgent. In this study, a nano-zero valent iron/periodate (nZVI-BC/PI) advanced oxidation system has been constructed, achieving a rapid degradation of acetaminophen (ACT, 1 mg/L) within 1 min (100 % at pH = 11) at low temperature (5℃). This system shows a great degradation in a wide range of pH (1 âˆ¼ 11), improving the pH limitation of PI oxidation system. During the reaction process, ·OH as the main active species collaborate with 1O2, Fe (IV), ·O2- and electron transfer to degrade ACT. In this system, iron ion leaching is low (0.019 mg/L), ACT was effectively degraded (74.36 %∼97.32 %) under different water, moreover, the material has an expected recyclability. The research provides a significant guidance for the advanced treatment of wastewater especially in cold regions.

Efficient degradation of antibiotic wastewater by biochar derived from water hyacinth stems via periodate activation: pyridinic N and carbon structures improved the electron transfer process.

Biochar-activated periodate (PI) is a promising technology toward antibiotic wastewater purification. However, the mechanism of pyrolysis temperature on PI activation efficiency by biochar has not yet been revealed. Herein, this work selected water hyacinth stems as raw materials to prepare biochar with different pyrolysis temperatures (400, 500, 600, and 700 °C), and applied it to degrade tetracycline (TC) wastewater through PI activation. The results show that biochar with a pyrolysis temperature of 700 °C (BC-700) possesses the best TC degradation performance (∼100% within 30 min). Besides, the degradation of TC by BC-700 is less interfered by coexisting anions and water matrix, and exhibits good reusability. Quenching experiments and open circuit voltage tests verified that IO3•, 1O2, and reactive complex BC-PI* are active species involved in TC degradation. In addition, by constructing the relationship between biochar surface properties and degradation rate kobs, it was revealed that the dominant role of pyridinic N in PI adsorption and formation of reactive complexes as well as the promotion of sp2-hybridized carbon in the electron transfer process. This work provides novel insights into the application of biochar in antibiotic wastewater treatment via PI activation.

Recent advances on the preparation conditions, structural characteristics, physicochemical properties, functional properties and potential applications of dialdehyde starch: A review.

Starch, a natural storage polysaccharide of plant kingdom, has many industrial applications. However, native starch has some inherent shortages, which can be overcome by structural modification. Dialdehyde starch, one kind of oxidized starch produced by periodate oxidation, has good physical properties and bioactivities with wide applications in different fields. Dialdehyde starch is typically achieved by oxidizing native starch slurry through periodate oxidation under controlled reaction conditions. Several factors including the source of starch, the type of oxidant, the molar ratio of oxidant to starch, reaction temperature, reaction time and solution pH value can influence the synthesis of dialdehyde starch. Dialdehyde starch shows different spectroscopic/chromatographic characters and physicochemical properties from native starch. Moreover, dialdehyde starch exhibits good antioxidant activity, antimicrobial activity and cross-linking property. Based on these functional properties, dialdehyde starch has shown application potentials in food packaging, thermoplastic production, enzyme immobilization, heavy metal ion adsorption, drug delivery, wood adhesion and leather tanning. In this review, the preparation conditions, structural characteristics, physicochemical properties, functional properties and potential applications of dialdehyde starch are summarized for the first time. The future research and development prospects of dialdehyde starch are also discussed.

o-Semiquinone Radical and o-Benzoquinone Selectively Degrade Aniline Contaminants in the Periodate-Mediated Advanced Oxidation Process.

Advanced oxidation processes (AOPs) often employ strong oxidizing inorganic radicals (e.g., hydroxyl and sulfate radicals) to oxidize contaminants in water treatment. However, the water matrix could scavenge the strong oxidizing radicals, significantly deteriorating the treatment efficiency. Here, we report a periodate/catechol process in which reactive quinone species (RQS) including the o-semiquinone radical (o-SQ•-) and o-benzoquinone (o-Q) were dominant to effectively degrade anilines within 60 s. The second-order reaction rate constants of o-SQ•- and o-Q with aniline were determined to be 1.0 × 108 and 4.0 × 103 M-1 s-1, respectively, at pH 7.0, which accounted for 21% and 79% of the degradation of aniline with a periodate-to-catechol molar ratio of 1:1. The major byproducts were generated via addition or polymerization. The RQS-based process exhibited excellent anti-interference performance in the degradation of aniline-containing contaminants in real water samples in the presence of diverse inorganic ions and organics. Subsequently, we extended the RQS-based process by employing tea extract and dissolved organic matter as catechol replacements as well as metal ions [e.g., Fe(III) or Cu(II)] as periodate replacements, which also exhibited good performance in aniline degradation. This study provides a novel strategy to develop RQS-based AOPs for the highly selective degradation of aniline-containing emerging contaminants.

Fluorescent periodic acid Schiff-like staining combined with standard cytologic staining of the same cytologic specimen may facilitate cytopathologic diagnosis.

BACKGROUND: Periodic acid Schiff (PAS) staining which detects glycogen and mucosubstances is frequently used as an ancillary method for an accurate cytopathologic diagnosis. Unfortunately, cytologic slides for PAS stain are not routinely prepared. Aqueous 7-amino-4-methylcoumarin (AMC) is colorless and transparent under bright field illumination but exhibits strong fluorescence under ultraviolet (UV) light and can be used as a Schiff reagent. We recently reported that combining [author: Please define (H&E) in the first occurrence if necessary.]H&E and AMC is useful for histopathologic diagnosis of various disease conditions. In this study, we investigated whether standard cytologic staining (Papanicolaou [Pap] and Giemsa) combined with AMC was useful for cytopathologic analysis. METHODS: Specimens of non-neoplastic human tissues and archived cytologic specimens of various disease conditions were stained with a combination of Pap and AMC (Pap/AMC) or Giemsa and AMC (Giemsa/AMC). RESULTS: The addition of AMC had no significant effect on Pap or Giemsa staining, and the cytomorphology under bright field microscopy was perfectly preserved. The AMC fluorescent signals observed under UV light were intense and the staining pattern was identical to that obtained by PAS staining. Diastase digestion differentiated glycogen from other AMC-positive elements. The efficacy of using Pap/AMC and Giemsa/AMC for archived cytologic specimens was demonstrated in several diseases including cases of endometrial carcinoma, adenoid cystic carcinoma, metastatic signet-ring cell carcinoma, candidiasis, and trichomoniasis. CONCLUSION: Pap/AMC and Giemsa/AMC are useful in aiding cytopathologic diagnosis especially when the information gained from PAS staining is critical and cytologic specimens for PAS are not available.

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

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

A step towards tuning the jute fiber structure and properties by employing sodium periodate oxidation and coating with alginate.

This paper outlines a novel simple protocol for tuning the structure and properties of jute using sodium periodate (NaIO4) oxidation and coating with alginate. When compared to the raw jute, fabrics oxidized with a 0.2 or 0.4 % NaIO4 solution for 30-120 min exhibited an increased aldehyde group content (0.185 vs. 0.239-0.398 mmol/g), a significantly increased negative zeta potential (from -8.57 down to -20.12 mV), a slight disruption of fiber crystallinity, 15.1-37.5 % and 27.9-49.8 % lower fabric maximum force and stiffness, respectively. Owing to the removal of hydrophobic surface barrier, decreased crystallinity index and the presence of micropores on the fabrics' surfaces, oxidized fabrics have a 22.3-29.6 % improved ability for moisture sorption compared to raw fabric. Oxidized fabrics characterized by very long wetting times and excellent antioxidant activities (> 98 %), can find applications as hydrophobic packaging materials. To further extend the utilization of jute in biocarpet engineering such as water-binding geo-prebiotic supports, oxidized fabrics were coated with alginate resulting in 7.9-24.9 % higher moisture sorption and 352-660 times lower wetting times than their oxidized counterparts. This modification protocol has never been applied to lignocellulosic fibers and sheds new light on obtaining jute fabrics with tuned structure and properties intended for various applications.

Clear cell urothelial carcinoma of bladder: Case report of a rare and aggressive variant with review of literature.

Clear cell urothelial carcinoma is a rare variant of urothelial carcinoma. It's recognition and accurate diagnosis are essential in deciding appropriate treatment protocols considering the prognosis of this variant. A 57-year-old male presented with a history of hematuria and lower urinary tract symptoms for 6 months. Microscopically, the tumor was arranged in sheets and had a nested pattern. The tumor was composed of round to polygonal cells with abundant clear cytoplasm (>90% clear cell differentiation), resembling a conventional clear renal cell carcinoma. On special stain, the tumor was positive for periodic acid-Schiff (PAS) and negative for periodic acid-Schiff with diastase (PAS-D) and mucicarmine stain. The urothelial origin of clear cells was confirmed by positivity for GATA Binding protein 3(GATA3) and High Molecular Weight Cytokeratin (HMWCK) immunohistochemistry and negativity for NK3 homeobox 1(NKX3.1), Prostate specific antigen (PSA) and Paired box gene 8 (PAX8) immunohistochemistry.

Preordering Periodic Acid-Schiff Staining: A Quality Improvement Study.

ABSTRACT: Periodic acid-Schiff (PAS) stain is a commonly used ancillary test for inflammatory and infectious dermatoses, yet infrequently changes the diagnosis. Previous studies have shown that clinical suspicion and histopathologic features are poor predictors of PAS positivity. Current appropriate use criteria from the American Society of Dermatopathology supports PAS staining when histopathologic features could be consistent with a dermatophyte infection. At the authors' institution, PAS stains are preordered on biopsies of inflammatory and infectious diagnoses to aid in a timelier sign out. Our aim was to reduce the percentage of PAS stains preordered on all dermatology specimens over a 6-month period without reducing the percentage of fungal infections identified. Review of a 12-month preintervention period found that our laboratory received 6104 biopsies for which PAS stain was preordered on 616 (10.1%). Based on a review of the preintervention period, preordering PAS on cases with clinical suspicion for cutaneous T-cell lymphoma was stopped unless there was clinical suspicion for eczematous dermatitis, vesiculobullous disorders, or fungal infection. The proposed intervention resulted in a 3.7% reduction in the number of PAS stains ordered while PAS-positivity rate remained unchanged. The described quality improvement process may be used as a model for other laboratories.

Malakoplakia with aberrant ALK expression by immunohistochemistry: a case report.

BACKGROUND: Malakoplakia is a rare inflammatory disease of the urogenital tract. There have been no reports of malakoplakia expressing anaplastic lymphoma kinase (ALK) to date. Here, we present one case of malakoplakia with aberrant ALK expression by immunohistochemistry and discuss the clinical significance. CASE PRESENTATION: A 65-year-old Chinese woman with a history of diabetes presented with solid masses in the liver and kidney and elevated lesions on the mucosal surface of the colon. Right nephrectomy and partial liver resection were performed. Microscopically, sheets of histiocytes with poor intercellular adhesion were seen, with Michaelis-Gutmann bodies present in both the intracellular and extracellular interstitium. CD10-, CD68-, and CD163-positive cells were present, with Michaelis-Gutmann bodies confirmed by staining with Alcian blue, periodic acid-Schiff (PAS), periodic acid-Schiff with diastase, Von Kossa, and Prussian blue. Aberrant ALK1 and ALK (D5F3) expression was observed in the cytoplasm and nucleus of cells. However, ALK gene mutation was not detected by fluorescence in situ hybridization or whole exome next-generation sequencing. NGS revealed nine individual somatic gene mutations: GOT1L1, GLIS2, SPOUT1, TMEM97, MUC3A, NSD2, SFXN5, ADAD1 and RAD50. The significance of the somatic gene mutations detected in this study is not clear, and the relationship between them and malakoplakia cannot be clarified by existing scientific studies. The pathological diagnosis was malakoplakia with aberrant ALK expression by immunohistochemistry. The antibiotics imipenem and vancomycin were started based on the results of drug sensitivity analysis and the patient was subsequently discharged. She experienced no discomfort during 30 months of follow-up. CONCLUSION: This is the first reported case of malakoplakia with aberrant ALK expression, it should be differentiated from ALK-positive histiocytosis to avoid misdiagnosis.

0.01% Hypochlorous Acid Treats Aspergillus fumigatus Keratitis in Rats by Reducing Fungal Load and Inhibiting the Inflammatory Response.

Purpose: To investigate the antifungal and anti-inflammatory effects of 0.01% hypochlorous acid (HCLO) on rats with Aspergillus fumigatus keratitis. Methods: The time-kill assay and broth microdilution procedures were used in vitro to demonstrate that 0.01% HCLO was fungicidal and fungistatic. The severity of the disease was evaluated in vivo using a clinical score and slit-lamp photographs. Fungal load, polymorphonuclear neutrophil infiltration, and the production of related proteins were determined using colony plate counting, in vivo confocal microscopy, periodic acid-Schiff staining, fungal fluorescence staining, immunofluorescence staining, myeloperoxidase assay, and Western blotting. Result: In vitro, 0.01% HCLO can destroy A. fumigatus spores in 1 minute. The optical density of the 0.01% HCLO group was significantly lower than that of the phosphate-buffered saline control group (P < 0.01), and no visible mycelium was observed using a fluorescence microscope. 0.01% HCLO reduced the severity of A. fumigatus keratitis in rats by decreasing the clinical score, fungal loading (periodic acid-Schiff, plate count, and fungal fluorescence staining), and inhibiting neutrophil infiltration and activity (immunofluorescence staining and myeloperoxidase). Furthermore, the Western blot analysis revealed that 0.01% HCO decreased protein expression levels of tumor necrosis factor-α and IL-1ß. Conclusions: According to our findings, 0.01% HCLO can kill A. fumigatus spores in vitro. It has antifungal and anti-inflammatory effects on A. fumigatus keratitis in rats. It also inhibited A. fumigatus growth; decreased neutrophil infiltration, tumor necrosis factor-α, and IL-1ß expression; and provided a potential treatment for fungal keratitis. Translational Relevance: This study provides a potential treatment for fungal keratitis in the clinic.

Detection of bacteria in dental samples using the Periodic acid-Schiff (PAS) histological stain.

The bacterial cell wall mainly consists of glycoproteins and polysaccharides, which could be detected in dental tissue with specific stain protocols. The present study aimed to investigate bacteria stainability in dental histological samples of human teeth by a histochemical method. Eight extracted teeth, because severely decayed, were decalcified, dehydrated, paraffin-embedded, and serially sectioned at 4 µm thickness each. The serial sections were then stained with Periodic acid-Schiff (PAS). Furthermore, SEM analysis was performed on the same slide of one previously histologically investigated tooth to acquire more details on the structures stained by the PAS method obtained from the histological procedures. Afterward, some American Type Culture Collection (ATCC) strains, smeared on glass slides, were stained following the staining method used in histological samples. Stained rod and cocci forms by PAS stain, observed under light microscopy, were predominantly detected inside dentinal tubules and root canal space of histologically examined specimens, suggesting their bacterial origin. Additional SEM analysis on the identical histological stained slide showed the precise nature of these forms (bacteria) and supplemental information regarding their vitality status. In addition, ATCC smeared strain samples showed variable PAS stainability of microorganisms investigated. Due to its properties, the PAS histochemical stain could be a valid and helpful aid for non- or weakly stainable microorganisms in infected tissues to be associated with other methods of investigation.

Multi-Detection Size Exclusion Chromatography as an Advanced Tool for Monitoring Enzyme-Antibody Conjugation Reaction and Quality Control of a Final Product.

The multi-detection size exclusion chromatography (SEC) has been recognized as an advanced analytical technique for the characterization of macromolecules and process control, as well as the manufacturing and formulation of biotechnology products. It reveals reproducible molecular characterization data, such as molecular weight and its distribution, and the size, shape, and composition of the sample peaks. The aim of this work was to investigate the potential and suitability of the multi-detection SEC as a tool for surveillance over the molecular processes during the conjugation reaction between the antibody (IgG) and horseradish peroxidase (HRP), and demonstrate the plausibility of its application in the quality control of the final product, the IgG-HRP conjugate. Guinea pig anti-Vero IgG-HRP conjugate was prepared using a modified periodate oxidation method, based on periodate oxidation of the carbohydrate side chains of HRP, followed by the formation of Schiff bases between the activated HRP and amino groups of the IgG. The quantitative molecular characterization data of the starting samples, intermediates, and final product were obtained by multi-detection SEC. Titration of the prepared conjugate was performed by the ELISA and its optimal working dilution was determined. This methodology proved to be a promising and powerful technology for the IgG-HRP conjugate process control and development, as well as for the quality control of the final product, as verified by the analysis of several commercially available reagents.

Disseminated Rasamsonia argillacea infection in a dog.

CASE HISTORY: A 4-year-old, male neutered Borzoi presented for unlocalised pain and frequent episodes of vocalisation. CLINICAL FINDINGS: Pain was localised to the lumbar spine and radiographs revealed a L3-L4 lesion consistent with discospondylitis. The dog was treated for presumptive bacterial discospondylitis with surgical debridement, spinal stabilisation, and cephalexin. Samples collected from the affected intervertebral disc at the time of surgery revealed lymphoplasmacytic inflammation with no causative agent identified on histopathology or bacterial culture. After an initial period of improvement, signs recurred despite an 8-week antibiotic course, with the development of inappetence, weight loss, polydipsia, and polyuria. Repeat radiographs revealed a new cervical intervertebral lesion, and concurrent pyelonephritis was diagnosed based on blood and urine results. Fungal culture of urine resulted in growth of Rasamsonia argillacea species complex and disseminated fungal disease was clinically diagnosed. Antifungal treatment was commenced, however the dog deteriorated, and euthanasia was performed. PATHOLOGICAL FINDINGS: Multifocal white plaques were grossly visualised in the spleen, mesenteric lymph nodes, cervical vertebrae, and kidneys. Periodic acid-Schiff-positive, fine, parallel-walled, occasionally branching, septate hyphae 5-10 µm in diameter, and conidia 5-7 µm in diameter were found on sectioning all organs. R. argillacea species complex was identified by fungal culture of urine and was considered the species of fungal organism seen histologically. The isolate was subsequently confirmed as R. argillacea by DNA sequencing. DIAGNOSIS: Disseminated Rasamsonia argillacea infection. CLINICAL RELEVANCE: Rasamsonia argillacea species complex is a recognised invasive mycosis in veterinary medicine, with disseminated disease causing significant clinical complications and death. This is believed to be the first report of infection caused by R. argillacea in a dog in Australasia and highlights the importance of awareness of a potential fungal aetiology in dogs with discospondylitis.Abbreviations: CLSI: Clinical and Laboratory Standards Institute; CRI: Constant rate infusion; MEC: Minimum effective concentration; MIC: Minimum inhibitory concentration; PAS: Periodic acid-Schiff.