Secondary bacterial and fungal infections in critically ill COVID‐19 patients: Impact on antimicrobial resistance

Background: The primary burden among severely ill COVID-19 cases allocated to ICUs is secondary bacterial and fungal infections. Antimicrobial resistance is aggravated more likely by empiric overusing of antimicrobials. This study aimed to assess the microbiological profile of fungal and bacterial superinfections in laboratory confirmed COVID-19 cases and their antimicrobial susceptibility pattern. Methods: Various clinical samples were obtained from 117 critically ill COVID-19 patients in the clinical suspicion of secondary infections for assessing the pathogens accountable for the superinfections and their antimicrobial susceptibility pattern according to standard microbiological procedures. Results: Among 117 COVID-19 patients allocated to ICU, 68 (58%) had secondary infections. The most prevalent infection was of the lower respiratory tract. Most infections were bacterial 85.8%. Gram-negative isolates were the most predominant strains, accounting for 71.7%. among them, Klebsiella pneumoniae 43.4 % and Acinetobacter baumannii 20.7% were the most predominant. Majority of the bacterial strains were multidrug-resistant, all gram-negative strains showed one hundred percent resistance rate to cephalosporins, amoxicillin, and amoxicillin-clavulanic. The lowest resistance was observed for tigecycline. All gram-positive strains were susceptible to linezolid and vancomycin. Additionally, all candida isolates were susceptible to the tested antifungals. Conclusions: In hospitalized severely ill COVID-19 patients, secondary infections are most frequently caused by Gram-negative pathogens exhibiting high rate of antibiotic resistance and are associated with poor outcomes. Strict adherence to infection control measures as well as regular microbiological surveillance are required

Egypt Human Rights Report

human development, human rights

Reduced axonal diameter of peripheral nerve fibres in a mouse model of Rett syndrome

Rett syndrome (RTT) is a neurological disorder characterized by motor and cognitive impairment, autonomic dysfunction and a loss of purposeful hand skills. In the majority of cases, typical RTT is caused by de novo mutations in the X-linked gene, MECP2. Alterations in the structure and function of neurons within the central nervous system of RTT patients and Mecp2-null mouse models are well established. In contrast, few studies have investigated the effects of MeCP2-deficiency on peripheral nerves. In this study, we conducted detailed morphometric as well as functional analysis of the sciatic nerves of symptomatic adult female Mecp2+/- mice. We observed a significant reduction in the mean diameter of myelinated nerve fibers in Mecp2+/- mice. In myelinated fibers, mitochondrial densities per unit area of axoplasm were significantly altered in Mecp2+/- mice. However, conduction properties of the sciatic nerve of Mecp2 knockout mice were not different from control. These subtle changes in myelinated peripheral nerve fibers in heterozygous Mecp2 knockout mice could potentially explain some RTT phenotypes

Immunoelectron microscope localization of androgen receptors and proliferating cell nuclear antigen in the epithelial cells of albino rat ventral prostate

AbstractAndrogen receptor (AR) and proliferating cell nuclear antigen (PCNA) play a crucial role in development and progression of various prostatic diseases including prostatic carcinoma that is a leading cause of death in males. Previous studies have evaluated the expression pattern of AR and PCNA in prostate epithelial cells using immunohistochemistry (IHC). However, this technique has limited ability to identify their precise subcellular localization. Therefore, the aim of this study was to localize, subcellularly, AR and PCNA in the secretory epithelial cells of rat ventral prostate using post embedding immunogold-electron microscopy. The ventral lobes were dissected from six adult male albino rats after being perfused with paraformaldehyde. Some specimens were immuno-labeled with AR or PCNA and others were processed for immunoelectron microscope of AR and PCNA using 15-nm gold conjugated secondary antibodies. The results showed that, by immunoperoxidase reaction, AR and PCNA were localized diffusely throughout the nuclei of the epithelial cells of prostatic acini without visible cytoplasmic expression. However, the higher resolution immuno-electron microscopy was able to detect AR and PCNA in the nucleus and some cytoplasmic organelles. In conclusion, this study emphasizes the importance of immuoelectron microscopy in precise localization of AR and PCNA at the subcelullar levels in the secretory epithelial cells of the rat prostatic acini. These findings will help to further understand the mechanism of action of these receptors under normal and pathological conditions that could have future clinical application after careful human investigation

Nisin inducible production of listeriolysin O in Lactococcus lactis NZ9000

<p>Abstract</p> <p>Background</p> <p><it>Listeria monocytogenes </it>is a well-characterized food-borne pathogen that infects pregnant women and immunocompromised individuals. Listeriolysin O (LLO) is the major virulence factor of the pathogen and is often used as a diagnostic marker for detection of <it>L. monocytogenes</it>. In addition, LLO represents a potent antigen driving T cell-mediated immunity during infection. In the present work, <it>Lactococcus lactis </it>NZ9000 was used as an expression host to hyper-produce LLO under inducible conditions using the NICE (NIsin Controlled Expression) system. We created a modified pNZ8048 vector encoding a six-His-tagged LLO downstream of the strong inducible PnisA promoter.</p> <p>Results</p> <p>The constructed vector (pNZPnisA:CYTO-LLO) was expressed in <it>L. lactis </it>NZ9000 and was best induced at mid-log phase with 0.2% v/v nisin for 4 h statically at 30°C. Purification of the His-tagged LLO was accomplished by Ni-NTA affinity chromatography and functionality was confirmed through haemolytic assays. Total LLO yield (measured as total protein content) was 4.43–5.9 mg per litre culture and the haemolytic activity was still detectable after 8 months of storage at 4°C.</p> <p>Conclusion</p> <p>The LLO production method described in this work provides an approach to efficient LLO production in the Gram-positive <it>Lactococcus </it>bacterium to yield a significant source of the protein for research and diagnostic applications. Expression of LLO in <it>L. lactis </it>has a number of benefits over <it>E. coli </it>which may facilitate both <it>in vivo </it>and <it>in vitro </it>applications of this system.</p

Engineering flexible machine learning systems by traversing functionally-invariant paths

Transformers have emerged as the state of the art neural network architecture for natural language processing and computer vision. In the foundation model paradigm, large transformer models (BERT, GPT3/4, Bloom, ViT) are pre-trained on self-supervised tasks such as word or image masking, and then, adapted through fine-tuning for downstream user applications including instruction following and Question Answering. While many approaches have been developed for model fine-tuning including low-rank weight update strategies (eg. LoRA), underlying mathematical principles that enable network adaptation without knowledge loss remain poorly understood. Here, we introduce a differential geometry framework, functionally invariant paths (FIP), that provides flexible and continuous adaptation of neural networks for a range of machine learning goals and network sparsification objectives. We conceptualize the weight space of a neural network as a curved Riemannian manifold equipped with a metric tensor whose spectrum defines low rank subspaces in weight space that accommodate network adaptation without loss of prior knowledge. We formalize adaptation as movement along a geodesic path in weight space while searching for networks that accommodate secondary objectives. With modest computational resources, the FIP algorithm achieves comparable to state of the art performance on continual learning and sparsification tasks for language models (BERT), vision transformers (ViT, DeIT), and the CNNs. Broadly, we conceptualize a neural network as a mathematical object that can be iteratively transformed into distinct configurations by the path-sampling algorithm to define a sub-manifold of weight space that can be harnessed to achieve user goals.Comment: 22 page

Targeted DPPC/DMPG surface-modified voriconazole lipid nanoparticles control invasive pulmonary aspergillosis in immunocompromised population: in-vitro and in-vivo assessment

Invasive pulmonary aspergillosis (IPA) is the most devastating Aspergillus-related lung disease. Voriconazole (VRZ) is the first-line treatment against IPA. Despite availability in oral and parenteral dosage forms, risks of systemic toxicity dictate alternative pulmonary administration. Inspired by natural lung surfactants, dipalmitoylphosphatidylcholine/dimyristoylphosphatidylglycerol (DPPC/DMPG) surface-modified lipid nanoparticles (LNPs) were scrutinized for pulmonary administration. DPPC/DMPG-VRZ-LNPs prepared using ultrasonication/thin film hydration were investigated for colloidal properties over 3-month shelf storage. They were stable with a slight change in entrapment efficiency. They provided a sustained VRZ release over 24 h, with a rapid initial release. In vitro aerosolization indicated higher percentages of VRZ deposited on stages corresponding to secondary bronchi and alveolar ducts. Moreover, intrapulmonary administration maintained high lung VRZ concentration (27 ± 1.14 µg/g) after 6 h. A preclinical study using a cyclophosphamide-induced neutropenic rat model demonstrated a 3-fold reduction in BALF-Galactomannan down to 0.515 ± 0.22 µg/L confirming DPPC/DMPG-VRZ-LNPs potential in hyphal growth inhibition. Histopathological examination of infected/nontreated lung sections exhibited dense fungal load inside alveoli and blood vessels indicating massive tissue and angio-invasiveness. Nevertheless, DPPC/DMPG-VRZ-LNPs-treated animals displayed minimal hyphae with no signs of invasiveness. The developed bioinspired nanoparticles serve as prospective bioactive nanocarrier candidates for pulmonary administration of VRZ in the management of IPA

PpiA, a Surface PPIase of the Cyclophilin Family in Lactococcus lactis

Background: Protein folding in the envelope is a crucial limiting step of protein export and secretion. In order to better understand this process in Lactococcus lactis, a lactic acid bacterium, genes encoding putative exported folding factors like Peptidyl Prolyl Isomerases (PPIases) were searched for in lactococcal genomes. Results: In L. lactis, a new putative membrane PPIase of the cyclophilin subfamily, PpiA, was identified and characterized. ppiA gene was found to be constitutively expressed under normal and stress (heat shock, H2O2) conditions. Under normal conditions, PpiA protein was synthesized and released from intact cells by an exogenously added protease, showing that it was exposed at the cell surface. No obvious phenotype could be associated to a ppiA mutant strain under several laboratory conditions including stress conditions, except a very low sensitivity to H2O2. Induction of a ppiA copy provided in trans had no effect i) on the thermosensitivity of an mutant strain deficient for the lactococcal surface protease HtrA and ii) on the secretion and stability on four exported proteins (a highly degraded hybrid protein and three heterologous secreted proteins) in an otherwise wild-type strain background. However, a recombinant soluble form of PpiA that had been produced and secreted in L. lactis and purified from a culture supernatant displayed both PPIase and chaperone activities. Conclusions: Although L. lactis PpiA, a protein produced and exposed at the cell surface under normal conditions, displaye

Development of a novel AAV gene therapy cassette with improved safety features and efficacy in a mouse model of Rett syndrome

Rett syndrome (RTT), caused by loss-of-function mutations in the MECP2 gene, is a neurological disorder characterized by severe impairment of motor and cognitive functions. The aim of this study was to investigate the impact of vector design, dosage and delivery route on the efficacy and safety of gene augmentation therapy in mouse models of RTT. Our results show that AAV-mediated delivery of MECP2 to Mecp2-null mice by systemic administration, and utilizing a minimal endogenous promoter, was associated with a narrow therapeutic window and resulted in liver toxicity at higher doses. Lower doses of this vector significantly extended survival of mice lacking MeCP2 or expressing a mutant T158M allele but had no impact on RTT-like neurological phenotypes. Modifying vector design by incorporating an extended Mecp2 promoter and additional regulatory 3’-UTR elements significantly reduced hepatic toxicity after systemic administration. Moreover, direct cerebroventricular injection of this vector into neonatal Mecp2-null mice resulted in high brain transduction efficiency, increased survival and bodyweight and an amelioration of RTT-like phenotypes. Our results show that controlling levels of MeCP2 expression in the liver is achievable through modification of the expression cassette. However, it also highlights the importance of achieving high brain transduction to impact the RTT-like phenotypes

Exclusive expression of MeCP2 in the nervous system distinguishes between brain and peripheral Rett syndrome-like phenotypes

This is a pre-copyedited, author-produced version of an article accepted for publication in Human Molecular Genetics following peer review. The version of record Ross, P. D., et al. (2016). "Exclusive expression of MeCP2 in the nervous system distinguishes between brain and peripheral Rett syndrome-like phenotypes." Human Molecular Genetics 25(20): 4389-4404.] is available online at: https://doi.org/10.1093/hmg/ddw269Work in SC’s laboratory was supported by the Biotechnology and Biological Sciences Research Council (PhD studentship for PDR), a consortium grant from the Rett Syndrome Research Trust, the Chief Scientist Office (Scottish Executive Health Department) [grant ETM/334], RS Macdonald Charitable Trust, Rosetrees Trust [grant M530], and the Rett Syndrome Association Scotland. Work in AB’s laboratory was supported by a Consortium Grant from the Rett Syndrome Research Trust, by Wellcome Trust programme grant [091580] and by Wellcome Trust Centre Core Grant [092076]. Funding to pay the Open Access publication charges for this article was provided by the Scottish Executive Health Department