Pictorial Review of Post COVID-19 Acute Invasive Fungal Sinusitis: Clinical Radiologists' Perspective.

Acute invasive fungal sinusitis (AIFS) is a rapidly progressive infection predominantly seen in immunocompromised patients. There is an increasing incidence of AIFS post COVID-19 infection. Yet, there is sparse literature regarding spectrum of cross-sectional imaging findings (CT and MRI) in these patients, which is prudent for appropriate timely surgical intervention.

FoxC1 activates limbal epithelial stem cells following corneal epithelial debridement.

Limbal epithelial stem cells are not only critical for corneal epithelial homeostasis but also have the capacity to change from a relatively quiescent mitotic phenotype to a rapidly proliferating cell in response to population depletion following corneal epithelial wounding. Pax6 mice display many abnormalities including corneal vascularization and these aberrations are consistent with a limbal stem cell deficiency (LSCD) phenotype. FoxC1 has an inhibitory effect on corneal avascularity and a positive role in stem cell maintenance in many tissues.

In vitro modeling and rescue of ciliopathy associated with IQCB1/NPHP5 mutations using patient-derived cells.

Mutations in the IQ calmodulin-binding motif containing B1 (IQCB1)/NPHP5 gene encoding the ciliary protein nephrocystin 5 cause early-onset blinding disease Leber congenital amaurosis (LCA), together with kidney dysfunction in Senior-Løken syndrome. For in vitro disease modeling, we obtained dermal fibroblasts from patients with NPHP5-LCA that were reprogrammed into induced pluripotent stem cells (iPSCs) and differentiated into retinal pigment epithelium (RPE) and retinal organoids. Patient fibroblasts and RPE demonstrated aberrantly elongated ciliary axonemes.

Gene Therapy of Dominant CRX-Leber Congenital Amaurosis using Patient Stem Cell-Derived Retinal Organoids.

Mutations in the photoreceptor transcription factor gene cone-rod homeobox (CRX) lead to distinct retinopathy phenotypes, including early-onset vision impairment in dominant Leber congenital amaurosis (LCA). Using induced pluripotent stem cells (iPSCs) from a patient with CRX-I138fs48 mutation, we established an in vitro model of CRX-LCA in retinal organoids that showed defective photoreceptor maturation by histology and gene profiling, with diminished expression of visual opsins. Adeno-associated virus (AAV)-mediated CRX gene augmentation therapy partially restored photoreceptor phenotype and expression of phototransduction-related genes as determined by single-cell RNA-sequencing.

A Common Outer Retinal Change in Retinal Degeneration by Optical Coherence Tomography Can Be Used to Assess Outcomes of Gene Therapy.

Identifying early disease hallmarks in animal models with slow disease progression may expedite disease detection and assessment of treatment outcomes. Using optical coherence tomography, a widely applied noninvasive method for monitoring retinal structure changes, we analyzed retinal optical sections from six mouse lines with retinal degeneration caused by mutations in different disease-causing genes. While images from wild-type mice revealed four well-separated hyper-reflective bands in the outer retina (designated as outer retina reflective bands, ORRBs) at all ages, the second band (ORRB2) and the third band (ORRB3) were merged in retinas of five mutant mouse lines at early ages, suggesting the pathological nature of this alteration.

A CEP290 C-Terminal Domain Complements the Mutant CEP290 of Rd16 Mice In Trans and Rescues Retinal Degeneration.

Mutations in CEP290 cause ciliogenesis defects, leading to diverse clinical phenotypes, including Leber congenital amaurosis (LCA). Gene therapy for CEP290-associated diseases is hindered by the 7.4 kb CEP290 coding sequence, which is difficult to deliver in vivo.

Retinal AAV8-RS1 Gene Therapy for X-Linked Retinoschisis: Initial Findings from a Phase I/IIa Trial by Intravitreal Delivery.

This study evaluated the safety and tolerability of ocular RS1 adeno-associated virus (AAV8-RS1) gene augmentation therapy to the retina of participants with X-linked retinoschisis (XLRS). XLRS is a monogenic trait affecting only males, caused by mutations in the RS1 gene. Retinoschisin protein is secreted principally in the outer retina, and its absence results in retinal cavities, synaptic dysfunction, reduced visual acuity, and susceptibility to retinal detachment.

Molecular codes for cell type specification in Brn3 retinal ganglion cells.

Visual information is conveyed from the eye to the brain by distinct types of retinal ganglion cells (RGCs). It is largely unknown how RGCs acquire their defining morphological and physiological features and connect to upstream and downstream synaptic partners. The three Brn3/Pou4f transcription factors (TFs) participate in a combinatorial code for RGC type specification, but their exact molecular roles are still unclear.

Nrl knockdown by AAV-delivered CRISPR/Cas9 prevents retinal degeneration in mice.

In retinitis pigmentosa, loss of cone photoreceptors leads to blindness, and preservation of cone function is a major therapeutic goal. However, cone loss is thought to occur as a secondary event resulting from degeneration of rod photoreceptors. Here we report a genome editing approach in which adeno-associated virus (AAV)-mediated CRISPR/Cas9 delivery to postmitotic photoreceptors is used to target the Nrl gene, encoding for Neural retina-specific leucine zipper protein, a rod fate determinant during photoreceptor development.

Determination of five potential genotoxic impurities in dalfampridine using liquid chromatography.

A sensitive and selective HPLC method was developed for identification and quantification of five Potential genotoxic impurities (PGIs) viz. Impurity-I, Impurity-II, Impurity-III, Impurity-IV and Impurity-V in Dalfampridine (Drug substance). The method utilizes Zorbax silica column (250mm×4.

Identification, synthesis and structural characterization of process related and degradation impurities of acrivastine and validation of HPLC method.

Four impurities (Imp-I-IV) were detected using gradient HPLC method in few laboratory batches of acrivastine in the level of 0.03-0.12% and three impurities (Imp-I-III) were found to be known and one (Imp-IV) was unknown.

A visual circuit uses complementary mechanisms to support transient and sustained pupil constriction.

Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear. Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters.

Ocular and systemic safety of a recombinant AAV8 vector for X-linked retinoschisis gene therapy: GLP studies in rabbits and Rs1-KO mice.

X-linked retinoschisis (XLRS) is a retinal disease caused by mutations in the gene encoding the protein retinoschisin (RS1) and is one of the most common causes of macular degeneration in young men. Our therapeutic approach for XLRS is based on the administration of AAV8-scRS/IRBPhRS, an adeno-associated viral vector coding the human RS1 protein, via the intravitreal (IVT) route. Two Good Laboratory Practice studies, a 9-month study in New Zealand White rabbits (n = 124) injected with AAV8-scRS/IRBPhRS at doses of 2E9, 2E10, 2E11, and 1.

Simple Isocratic HPLC Method for Determination of Enantiomeric Impurity in Besifloxacin Hydrochloride.

Besifloxacin is a unique chiral broad-spectrum flouroquinolone used in the treatment of bacterial conjunctivitis. R-form of besifloxacin hydrochloride shows higher antibacterial activity as compared to the S-isomer. Therefore, it is necessary to establish chiral purity.

Retinal Structure and Gene Therapy Outcome in Retinoschisin-Deficient Mice Assessed by Spectral-Domain Optical Coherence Tomography.

Purpose: Spectral-domain optical coherence tomography (SD-OCT) was used to characterize the retinal phenotype, natural history, and treatment responses in a mouse model of X-linked retinoschisis (Rs1-KO) and to identify new structural markers of AAV8-mediated gene therapy outcome.

Methods: Optical coherence tomography scans were performed on wild-type and Rs1-KO mouse retinas between 1 and 12 months of age and on Rs1-KO mice after intravitreal injection of AAV8-scRS/IRBPhRS (AAV8-RS1). Cavities and photoreceptor outer nuclear layer (ONL) thickness were measured, and outer retina reflective band (ORRB) morphology was examined with age and after AAV8-RS1 treatment.

Preclinical Dose-Escalation Study of Intravitreal AAV-RS1 Gene Therapy in a Mouse Model of X-linked Retinoschisis: Dose-Dependent Expression and Improved Retinal Structure and Function.

Gene therapy for inherited retinal diseases has been shown to ameliorate functional and structural defects in both animal models and in human clinical trials. X-linked retinoschisis (XLRS) is an early-age onset macular dystrophy resulting from loss of an extracellular matrix protein (RS1). In preparation for a human clinical gene therapy trial, we conducted a dose-range efficacy study of the clinical vector, a self-complementary AAV delivering a human retinoschisin (RS1) gene under control of the RS1 promoter and an interphotoreceptor binding protein enhancer (AAV8-scRS/IRBPhRS), in the retinoschisin knockout (Rs1-KO) mouse.

Long-term rescue of cone photoreceptor degeneration in retinitis pigmentosa 2 (RP2)-knockout mice by gene replacement therapy.

Retinal neurodegenerative diseases are especially attractive targets for gene replacement therapy, which appears to be clinically effective for several monogenic diseases. X-linked forms of retinitis pigmentosa (XLRP) are relatively severe blinding disorders, resulting from progressive photoreceptor dysfunction primarily caused by mutations in RPGR or RP2 gene. With a goal to develop gene therapy for the XLRP-RP2 disease, we first performed detailed characterization of the Rp2-knockout (Rp2-KO) mice and observed early-onset cone dysfunction, which was followed by progressive cone degeneration, mimicking cone vision impairment in XLRP patients.

A long-term efficacy study of gene replacement therapy for RPGR-associated retinal degeneration.

Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene account for >70% of X-linked retinitis pigmentosa (XLRP) and 15-20% of all inherited retinal degeneration. Gene replacement therapy for RPGR-XLRP was hampered by the relatively slow disease progression in mouse models and by difficulties in cloning the full-length RPGR-ORF15 cDNA that includes a purine-rich 3'-coding region; however, its effectiveness has recently been demonstrated in four dogs with RPGR mutations. To advance the therapy to clinical stage, we generated new stable vectors in AAV8 or AAV9 carrying mouse and human full-length RPGR-ORF15-coding sequence and conducted a comprehensive long-term dose-efficacy study in Rpgr-knockout mice.

Preclinical safety evaluation of a recombinant AAV8 vector for X-linked retinoschisis after intravitreal administration in rabbits.

X-linked retinoschisis (XLRS) is a retinal disease caused by mutations in the gene encoding the protein retinoschisin (RS1) and one of the most common causes of macular degeneration in young men. Currently, no FDA-approved treatments are available for XLRS and a replacement gene therapy could provide a promising strategy. We have developed a novel gene therapy approach for XLRS, based on the administration of AAV8-scRS/IRBPhRS, an adeno-associated viral vector coding the human RS1 protein, via the intravitreal route.

Rd9 is a naturally occurring mouse model of a common form of retinitis pigmentosa caused by mutations in RPGR-ORF15.

Animal models of human disease are an invaluable component of studies aimed at understanding disease pathogenesis and therapeutic possibilities. Mutations in the gene encoding retinitis pigmentosa GTPase regulator (RPGR) are the most common cause of X-linked retinitis pigmentosa (XLRP) and are estimated to cause 20% of all retinal dystrophy cases. A majority of RPGR mutations are present in ORF15, the purine-rich terminal exon of the predominant splice-variant expressed in retina.

Identification of oxidative degradation impurities of olanzapine drug substance as well as drug product.

Impurities found in stressed and stability studies of olanzapine (polymorphic form-I) [1-7] in both drug substance and drug product are described. These impurities are identified as 4-(4-methyl-1-piperazinyl)-3-hydroxymethylidene-1H-benzo[b][1,4]diazepine-2(3H)-thione (hydroxymethylidene thione) and (Z)-4-(4-methyl-1-piperazinyl)-3-acetoxymethylidene-1H-benzo[b][1,4]diazapine-2(3H)-thione (acetoxymethylidene thione). An oxidative degradation pathway of olanzapine, for the formation of these impurities, has been proposed.

Potent immune responses and in vitro pro-inflammatory cytokine suppression by a novel adenovirus vaccine vector based on rare human serotype 28.

Adenovirus vaccine vectors derived from rare human serotypes have been shown to be less potent than serotype 5 (Ad5) at inducing immune responses to encoded antigens. To identify highly immunogenic adenovirus vectors, we assessed pro-inflammatory cytokine expression, binding to the CD46 receptor, and immunogenicity. Species D adenoviruses uniquely suppressed pro-inflammatory cytokines and induced high levels of type I interferon.

Optimized and validated spectrophotometric methods for the determination of raloxifene in pharmaceuticals using permanganate.

Two simple and sensitive spectrophotometric methods are described for the determination of raloxifene hydrochloride (RLX) in pure form and in tablets. The first method (method A) is based on the formation of a yellowish-brown chromogen peaking at 430 nm when RLX was reacted with permanganate in acetic acid medium. In the second method (method B), RLX was reacted with a measured excess of permanganate in H2SO4 medium followed by the spectrophotometric measurement of the unreacted KMnO4 at 550 nm.

Unusual detritylation of tritylated tetrazole in Sartan molecules.

Tritylated tetrazole of 2a underwent unusual detritylation under basic reaction condition during the synthesis of methyl ether of olmesartan medoxomil 1. The unusual detritylation was found to be a common feature in the case of all tetrazole containing Sartan molecules (3-7).