Experimental glaucoma microstent implantation in two animal models and human donor eyes-an ex vivo micro-computed tomography-based evaluation of applicability.

Background: Minimally invasive glaucoma surgery (MIGS) has become an important treatment approach for primary open angle glaucoma. Restoration of aqueous humour drainage by means of alloplastic implants represents a promising treatment option and is itself subject of methodological development. An adequate positioning in the targeted tissue regions is essential is important for the performance of our in-house developed Rostock glaucoma microstent (RGM). The aim of this study was to evaluate the applicability of two animal models and human donor eyes regarding RGM placement. Methods: Eyes were obtained from rabbits, pigs, and human body donations. After orbital exenterations, RGMs were placed in the anterior chamber draining in the subconjunctival space. X-ray contrast was increased by incubation in aqueous iodine solution for subsequent detailed micro-computed tomography (micro-CT)-based visualization and analysis. Results: In contrast to the human and porcine eyes, the stent extended far to the posterior pole with a more pronounced curvature along the globe in the rabbit eyes due to their smaller size. However, dysfunctional deformations were not depicted. Adequate positioning of the stent's inflow area in the anterior chamber and the outflow area in the Tenon space was achieved in both the animal models and the human eye. Conclusions: Micro-CT has proven to be a valuable tool for postoperative ex vivo evaluation of glaucoma drainage devices in its entire complexity. With regard to morphology, the porcine eye is the ideal animal model to test implantation procedures of the RGM. Nevertheless, rabbit eye morphology facilitates successful implantation results and provides all prerequisites for preclinical animal studies.

Photophysical, photobiological, and mycobacteria photo-inactivation properties of new meso-tetra-cationic platinum(II) metalloderivatives at meta position.

In this manuscript, we report the photo-inactivation evaluation of new tetra-cationic porphyrins with peripheral Pt(II) complexes ate meta N-pyridyl positions in the antimicrobial photodynamic therapy (aPDT) of rapidly growing mycobacterial strains (RGM). Four different metalloderivatives were synthetized and applied. aPDT experiments in the strains of Mycobacteroides abscessus subsp. Abscessus (ATCC 19977), Mycolicibacterium fortuitum (ATCC 6841), Mycobacteroides abscessus subsp. Massiliense (ATCC 48898), and Mycolicibacterium smegmatis (ATCC 700084) conducted with adequate concentration of photosensitizers (PS) under white-light conditions at 90 min (irradiance of 50 mW cm-2 and a total light dosage of 270 J cm-2) showed that the Zn(II) derivative is the most effective PS significantly reduced the concentration of viable mycobacteria. The effectiveness of the molecule as PS for PDI studies is also clear with mycobacteria, which is strongly related with the porphyrin peripheral charge and coordination platinum(II) compounds and consequently about the presence of metal center ion. This class of PS may be promising antimycobacterial aPDT agents with potential applications in medical clinical cases and bioremediation.

Gene expression in notochord and nuclei pulposi: a study of gene families across the chordate phylum.

The transition from notochord to vertebral column is a crucial milestone in chordate evolution and in prenatal development of all vertebrates. As ossification of the vertebral bodies proceeds, involutions of residual notochord cells into the intervertebral discs form the nuclei pulposi, shock-absorbing structures that confer flexibility to the spine. Numerous studies have outlined the developmental and evolutionary relationship between notochord and nuclei pulposi. However, the knowledge of the similarities and differences in the genetic repertoires of these two structures remains limited, also because comparative studies of notochord and nuclei pulposi across chordates are complicated by the gene/genome duplication events that led to extant vertebrates. Here we show the results of a pilot study aimed at bridging the information on these two structures. We have followed in different vertebrates the evolutionary trajectory of notochord genes identified in the invertebrate chordate Ciona, and we have evaluated the extent of conservation of their expression in notochord cells. Our results have uncovered evolutionarily conserved markers of both notochord development and aging/degeneration of the nuclei pulposi.

Comparative genomic analysis reveals differential genomic characteristics and featured genes between rapid- and slow-growing non-tuberculous mycobacteria.

Introduction: Non-tuberculous mycobacteria (NTM) is a major category of environmental bacteria in nature that can be divided into rapidly growing mycobacteria (RGM) and slowly growing mycobacteria (SGM) based on their distinct growth rates. To explore differential molecular mechanisms between RGM and SGM is crucial to understand their survival state, environmental/host adaptation and pathogenicity. Comparative genomic analysis provides a powerful tool for deeply investigating differential molecular mechanisms between them. However, large-scale comparative genomic analysis between RGM and SGM is still uncovered. Methods: In this study, we screened 335 high-quality, non-redundant NTM genome sequences covering 187 species from 3,478 online NTM genomes, and then performed a comprehensive comparative genomic analysis to identify differential genomic characteristics and featured genes/protein domains between RGM and SGM. Results: Our findings reveal that RGM has a larger genome size, more genes, lower GC content, and more featured genes/protein domains in metabolism of some main substances (e.g. carbohydrates, amino acids, nucleotides, ions, and coenzymes), energy metabolism, signal transduction, replication, transcription, and translation processes, which are essential for its rapid growth requirements. On the other hand, SGM has a smaller genome size, fewer genes, higher GC content, and more featured genes/protein domains in lipid and secondary metabolite metabolisms and cellular defense mechanisms, which help enhance its genome stability and environmental adaptability. Additionally, orthogroup analysis revealed the important roles of bacterial division and bacteriophage associated genes in RGM and secretion system related genes for better environmental adaptation in SGM. Notably, PCoA analysis of the top 20 genes/protein domains showed precision classification between RGM and SGM, indicating the credibility of our screening/classification strategies. Discussion: Overall, our findings shed light on differential underlying molecular mechanisms in survival state, adaptation and pathogenicity between RGM and SGM, show the potential for our comparative genomic pipeline to investigate differential genes/protein domains at whole genomic level across different bacterial species on a large scale, and provide an important reference and improved understanding of NTM.

Disseminated cutaneous Mycobacterium chelonae infection secondary to an indwelling catheter in an immunocompetent host.

Background: Mycobacterium chelonae is a species of nontuberculous mycobacteria that typically causes localized cutaneous disease in immunocompetent hosts. There have been few reports of disseminated infections in immunocompetent individuals which have often been associated with invasive medical procedures. Case Presentation: In this report, we describe a 43-year-old immunocompetent female with an implanted venous access device who presented with skin lesions increasing in size and frequency over the course of five months despite antimicrobial therapy. A diagnosis was not made until mycobacterial culture from a skin biopsy grew M. chelonae. Conclusion: Disseminated cutaneous M. chelonae infection can be a rare complication of indwelling venous catheterization among immunocompetent patients.

First report of disseminated Mycobacterium abscessus in an immunocompetent adult patient in Oman.

Mycobacterium abscessus is a ubiquitous rapid-growing mycobacterium that belongs to a diverse group of non-tuberculous mycobacteria. It can cause frequent and serious infections in patients with or without risk factors. This article reports a case of disseminated M. abscessus in an immunocompetent Omani male with native joint septic arthritis.

TGF-ß superfamily co-receptors in cancer.

Transforming growth factor-ß (TGF-ß) superfamily signaling via their cognate receptors is frequently modified by TGF-ß superfamily co-receptors. Signaling through SMAD-mediated pathways may be enhanced or depressed depending on the specific co-receptor and cell context. This dynamic effect on signaling is further modified by the release of many of the co-receptors from the membrane to generate soluble forms that are often antagonistic to the membrane-bound receptors. The co-receptors discussed here include TßRIII (betaglycan), endoglin, BAMBI, CD109, SCUBE proteins, neuropilins, Cripto-1, MuSK, and RGMs. Dysregulation of these co-receptors can lead to altered TGF-ß superfamily signaling that contributes to the pathophysiology of many cancers through regulation of growth, metastatic potential, and the tumor microenvironment. Here we describe the role of several TGF-ß superfamily co-receptors on TGF-ß superfamily signaling and the impact on cellular and physiological functions with a particular focus on cancer, including a discussion on recent pharmacological advances and potential clinical applications targeting these co-receptors.

Development of a nucleic acid chromatography assay for the detection of commonly isolated rapidly growing mycobacteria.

Introduction. Non-tuberculosis mycobacterium infections are increasing worldwide, including those caused by rapidly growing mycobacteria (RGM).Gap Statement. The identification of the aetiological agent in the context of infections is essential for the adoption of an adequate therapeutic approach. However, the methods for the rapid distinction of different RGM species are less than optimal.Aim. To develop a nucleic acid chromatography kit to identify clinically common RGM.Methodology. We tried to develop a nucleic acid chromatography kit designed to detect four RGM species (including three subspecies) i.e. Mycobacterium abscessus subsp. abscessus, Mycobacterium abscessus subsp. bolletii (detected as M. abscessus/bolletii) Mycobacterium abscessus subsp. massiliense, Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium peregrinum. The amplified target genes for each species/subspecies using multiplex PCR were analysed using a nucleic acid chromatography assay.Results. Among the 159 mycobacterial type strains and 70 RGM clinical isolates tested, the developed assay correctly identified all relevant RGM without any cross-reactivity or false-negatives. The limits of detection for each species were approximately 0.2 pg µl-1.Conclusion. The rapid and simple nucleic acid chromatography method developed here, which does not involve heat denaturation, may contribute to the rapid identification and treatment of RGM infections.

Improved phenotyping procedure for evaluating resistance in rice against gall midge (Orseolia oryzae, Wood-Mason).

BACKGROUND: The rice gall midge (RGM, Orseolia oryzae, Wood-Mason), an important stem-feeding pest worldwide, has caused serious production losses over the past decades. Rice production practices indicate that the most reliable method for managing RGM is the deployment of cultivars that incorporate host resistance. However, the conventional phenotypic screening method of rice resistance to RGM suggested by the International Rice Research Institute (IRRI) has been used for approximately 30 years, and only 12 rice varieties/lines (including controls) can be evaluated in one tray. It is not suitable for high-throughput phenotyping of rice germplasm. Moreover, a suitable method to prepare samples for molecular biological studies of rice resistance against RGM is imperative with the rapid development of modern molecular techniques. RESULTS: The proper density of seedlings/RGM was determined for four seeding arrangements. A high-throughput phenotyping method (HTPM) for 60 lines/varieties infested with 36 female RGM adults in one tray, as described by method 4-3 (seeded 60 lines/varieties), was developed and verified using mutant screening. Furthermore, one RGM resistance gene flanked by markers 12RM28346 and 12RM28739 on chromosome 12 was simultaneously detected using method 2-2 (seeded 30 lines/varieties in one tray) treated with 24 RGM and analyzed using conventional and simplified grading systems. Genetic analysis of the RGM resistance gene was confirmed using a method identical to that suggested by IRRI. Finally, one bucket with 24 seedlings treated with at least five female RGM adults was efficacious and could offer adequate samples for insect development observation or molecular biological studies. CONCLUSION: A highly efficient and reliable procedure for evaluation of resistance in rice to RGM was developed and improved, and was verified through mutant screening, gene mapping, genetic analysis, and insect growth and development observations.

Photo-damage promoted by tetra-cationic palladium(II) porphyrins in rapidly growing mycobacteria.

Antimicrobial photodynamic therapy (aPDT) has gained prominence in microbiology, especially in treating non-invasive infections. Diseases such as mycobacteriosis, which causes localized infections and has a slow treatment, tend to be future targets for this type of technology. Therefore, this study aimed to explore the action of two isomeric Pd(II)-porphyrins on fast-growing mycobacterial strains (RGM). Tetra-cationic porphyrins (4-PdTPyP and 3-PdTPyP) were synthesized and applied against standard strains of Mycobacteroides abscessus subsp. abscessus (ATCC 19977), Mycolicibacterium fortuitum (ATCC 6841), Mycolicibacterium smegmatis (ATCC 700084), and Mycobacteroides abscessus subsp. massiliense (ATCC 48898). Reactive oxygen species (ROS) scavengers were used in an attempt to determine possible ROS produced by the photosensitizers (PS) under study. Moreover, the impact of porphyrin on the mycobacterial surface was further evaluated by atomic force microscopy (AFM), and we observed significant damage on cells walls and altered nanomechanical and electrostatic adhesion properties. The results presented herein show that the positively charged porphyrin at the meta position (3-PdTPyP) was the most efficient PS against the RGM strains, and its bactericidal activity was proven in two irradiation sessions, with singlet oxygen species being the main ROS involved in this process. This study demonstrated the therapeutic potential of porphyrins, especially the 3-PdTPyP derivative.

Mycobacterium abscessus Ventriculoperitoneal Shunt Infection.

Mycobacterium abscessus is a rapidly growing mycobacterium (RGM) known to be abundant in soil, dust and water. Unlike other non-tuberculous mycobacteria, RGM is typically resistant to first-line anti-tuberculosis drugs. These organisms are known to cause community and hospital-acquired infections; however, central nervous system (CNS) infections caused by these pathogens have not been abundantly reported. As the use of vascular catheters and prosthetic devices is becoming more common, a rise in CNS infections secondary to M. abscessus has been noted. Here, we present such a case where the removal of a ventricular catheter was necessary to guarantee source control and eradication of the infection.

Decontamination Strategies Used for AFB Culture Significantly Reduce the Viability of Mycobacterium abscessus Complex in Sputum Samples from Patients with Cystic Fibrosis.

Nontuberculous mycobacteria are important respiratory pathogens in patients with cystic fibrosis (CF). For diagnosis, international guidelines recommend culture of sputum that has been decontaminated via chemical treatment. Fifty-six sputum samples from 32 patients known to be previously colonized or infected with NTM were subdivided, and the aliquots were subjected to six different decontamination strategies, followed by quantitative culture for NTM. Thirty sputum samples contained Mycobacterium abscessus complex (MABSC) and 11 contained Mycobacterium avium complex (MAC). Decontamination strategies included treatment with N-acetyl L-cysteine with 2% sodium hydroxide (NALC-NaOH), 4% NaOH, 1% chlorhexidine, 0.5 N sulfuric acid, 5% oxalic acid, double decontamination with NALC-NaOH, followed by 5% oxalic acid, and saline (0.85%) as a control. The samples were also cultured directly with no treatment. Treatment with NALC-NaOH resulted in an average reduction in colony count of 87% for MABSC when compared with direct culture. NaOH at 4% caused a 98.3% average reduction in colony count. All treatments that included NaOH resulted in colony counts that were statistically lower than those obtained from direct culture or the saline-treated control (p < 0.05). Standard treatments using sulfuric or oxalic acids were less deleterious, but still resulted in an average reduction in colony count of at least 30%. The viability of MAC was much less affected by most decontamination treatments. In conclusion, the viability of MABSC was severely compromised by standard decontamination regimens. This supports recent evidence showing that optimal recovery of MABSC is achieved by culture on an appropriate selective agar without decontamination of sputum samples.

Drug susceptibiity testing of nontuberculous mycobacteria by broth microdilution method.

INTRODUCTION: -Incidence of Nontuberculous mycobacteria (NTM) has been increasing in past few years. Treatment of NTM differs from Mycobacterium tuberculosis. For proper treatment, it's important to carry out Drug Susceptibility Testing of NTM. Method of DST for NTM is different from MTB and is not available in most laboratories. METHOD: -We performed DST on 122 isolates of NTM. Amikacin, Ciprofloxacin, Trimethoprim, Doxycycline, Moxifloxacin, Clarithromycin, Minocycline and Cefoxitin were used for Rapid Growing Mycobacteria (RGM) and Rifampicin, Clarithromycin, Ethambutol, Isoniazid and Moxifloxacin for Slow Growing Mycobacteria (SGM). M. avium Complex (MAC) was tested against Clarithromycin. Minimum inhibitor concentration was calculated as recommended by standard Clinical and Laboratory Standards Institute (CLSI) and Resazurin Microtitre Assay (REMA). RESULT: -Most of Rapid Growing Mycobacteria were sensitive to Amikacin (76.1%) and Moxifloxacin (46.47%) while Slow Growing Mycobacteria showed only 33.3% sensitivity to Rifampicin and Moxifloxacin and 42% to Clarithromycin. M. avium-intracellulare complex showed 45-50% sensitivity to Clarithromycin. Overall, 98% concordance (Kappa = 0.98; almost perfect; 95% CI = 0.966 to 0.996) was seen between standard and REMA method of DST of NTM. CONCLUSION: -Rapid growers showed good sensitivity to Amikacin and Moxifloxacin, while only one third SGM showed sensitivity to Rifampicin, Moxifloxacin and Clarithromycin. For proper management of NTM of eastern Rajasthan its important to know the DST profile in our area to initiate empirical therapy till the results of specific patient are available. REMA was found to give excellent concordance with standard method.

Endophthalmitis caused by Mycobacterium houstonense: case report.

BACKGROUND: Mycobacterium houstonense is rapidly growing mycobacteria (RGM) that belongs to M. fortuitum group. So far, there have been few associated reports of human diseases induced by M. houstonense worldwide. CASE PRESENTATION: We present a delayed-onset postoperative endophthalmitis caused by M. houstonense after glaucoma drainage implant (GDI) surgery. The ocular infection lasted for 2 months without appropriate treatment that developed into endophthalmitis and the patient underwent an emergency enucleation. CONCLUSION: Implant erosion and a delay in diagnosis of ocular infection could lead to irreversible damage as observed in our case. Ophthalmologists should be alert for ocular RGM infection, and prompt laboratory diagnosis with initiation of effective multidrug therapy might prevent loss of vision.

Repulsive Guidance Molecule A Regulates Adult Neurogenesis Via the Neogenin Receptor.

Repulsive guidance molecule A (RGMa) exhibits repulsive guidance of axonal growth and regulates neuronal differentiation during development of the mammalian brain. In this commentary, we describe the findings of our recent paper, "Repulsive Guidance Molecule A Suppresses Adult Neurogenesis," and discuss a possible model for RGMa suppression of newborn neurons that fail to properly migrate into the granular cell layer. In the study, we provided evidence that RGMa suppressed neurite growth and survival of newborn neurons in the adult dentate gyrus. This effect depends on the multifunctional Neogenin receptor expressed in adult neural stem cells through activation of the Rho-associated protein kinase leading to neurite growth inhibition and ultimately cell death. It should be noted that both RGMa and Neogenin interact with several well-described molecules, including bone morphogenetic proteins, that regulate neuronal development. Thus, it is likely that RGMa interacts with other intricate molecular networks that regulate adult neurogenesis.

Iterative energy self-calibration of Fe XANES spectra.

Determining the oxidation state of Fe through parameterization of X-ray absorption near-edge structure (XANES) spectral features is highly dependent on accurate and repeatable energy calibration between spectra. Small errors in energy calibration can lead to vastly different interpretations. While simultaneous measurement of a reference foil is often undertaken on X-ray spectroscopy beamlines, other beamlines measure XANES spectra without a reference foil and therefore lack a method for correcting energy drift. Here a method is proposed that combines two measures of Fe oxidation state taken from different parts of the spectrum to iteratively correct for an unknown energy offset between spectra, showing successful iterative self-calibration not only during individual beam time but also across different beamlines.

Iterative energy self-calibration of Fe XANES spectra. Erratum.

A correction is made to the paper by Jones et al. (2020). [J. Synchrotron Rad. (2020), 27, 207-211].

Infection of a Cardiac Implantable Electronic Device Caused by Mycolicibacterium litorale.

We report the first case of Mycolicibacterium litorale infection identified as a pacemaker infection. The patient was successfully treated by device extraction and combined antibiotic therapy. This case indicates the importance of the pathogenicity of rapidly growing mycobacteria in patients with cardiac implantable electronic device infections. (Level of Difficulty: Beginner.).

Rifamycin derivatives active against pathogenic rapidly-growing mycobacteria.

Infections due to rapidly growing mycobacteria (RGM), and in particular the RGM species Mycobacterium abscessus (Mab), are very difficult to treat and reports on novel therapeutic options are scarce. A hallmark of all pathogenic RGM species is their resistance to the four first-line drugs used to treat infections with Mycobacterium tuberculosis including rifampicin. This study demonstrates that modification of the rifampicin scaffold can restore rifampicin activity against the three most commonly isolated pathogenic RGM species including Mab. We also note that the structure-activity relationship for Mab is different as compared to the non-pathogenic RGM species Mycobacterium smegmatis.