Evaluation of Whole Genome Sequencing-Based Predictions of Antimicrobial Resistance to TB First Line Agents: A Lesson from 5 Years of Data.

Phenotypic susceptibility testing of the complex (MTBC) isolate requires culture growth, which can delay rapid detection of resistant cases. Whole genome sequencing (WGS) and data analysis pipelines can assist in predicting resistance to antimicrobials used in the treatment of tuberculosis (TB). This study compared phenotypic susceptibility testing results and WGS-based predictions of antimicrobial resistance (AMR) to four first-line antimicrobials-isoniazid, rifampin, ethambutol, and pyrazinamide-for MTBC isolates tested between the years 2018-2022.

Phenotypic amikacin resistance may not indicate poor response to amikacin in complex pulmonary disease.

When using amikacin to treat complex pulmonary disease (MAC-PD), a minimum inhibitory concentration resistance breakpoint of ≥64 mcg/mL is recommended. We explored whether amikacin resistance characterized by phenotypic drug susceptibility testing was associated with clinical outcomes or mutational resistance in a retrospective cohort of patients with MAC-PD. Despite little aminoglycoside exposure, amikacin resistance was common in our MAC-PD patients but was not associated with worse outcomes or gene mutations.

Characterization of Mycobacterium orygis, Mycobacterium bovis, and Mycobacterium caprae Infections in Humans in Western Canada.

Epidemiologic research on zoonotic tuberculosis historically used Mycobacterium bovis as a surrogate measure; however, increased reports of human tuberculosis caused by other animal-associated Mycobacterium tuberculosis complex members like Mycobacterium orygis necessitates their inclusion. We performed a retrospective cohort study including persons infected with any animal-lineage M tuberculosis complex species in Alberta, Canada, from January 1995 to July 2021, identifying 42 patients (20 M bovis, 21 M orygis, 1 M caprae). Demographic, epidemiologic, and clinical characteristics were compared against persons with culture-confirmed M tuberculosis infection.

Cortical astrocyte N-methyl-D-aspartate receptors influence whisker barrel activity and sensory discrimination in mice.

Astrocytes express ionotropic receptors, including N-methyl-D-aspartate receptors (NMDARs). However, the contribution of NMDARs to astrocyte-neuron interactions, particularly in vivo, has not been elucidated. Here we show that a knockdown approach to selectively reduce NMDARs in mouse cortical astrocytes decreases astrocyte Ca transients evoked by sensory stimulation.

Brain Pericyte Calcium and Hemodynamic Imaging in Transgenic Mice In Vivo.

Recent advances in protein biology and mouse genetics have made it possible to measure intracellular calcium fluctuations of brain cells in vivo and to correlate this with local hemodynamics. This protocol uses transgenic mice that have been prepared with a chronic cranial window and express the genetically encoded calcium indicator, RCaMP1.07, under the α-smooth muscle actin promoter to specifically label mural cells, such as vascular smooth muscle cells and ensheathing pericytes.

Cortical Circuit Activity Evokes Rapid Astrocyte Calcium Signals on a Similar Timescale to Neurons.

Sensory stimulation evokes intracellular calcium signals in astrocytes; however, the timing of these signals is disputed. Here, we used novel combinations of genetically encoded calcium indicators for concurrent two-photon imaging of cortical astrocytes and neurons in awake mice during whisker deflection. We identified calcium responses in both astrocyte processes and endfeet that rapidly followed neuronal events (∼120 ms after).

Long-term In Vivo Calcium Imaging of Astrocytes Reveals Distinct Cellular Compartment Responses to Sensory Stimulation.

Localized, heterogeneous calcium transients occur throughout astrocytes, but the characteristics and long-term stability of these signals, particularly in response to sensory stimulation, remain unknown. Here, we used a genetically encoded calcium indicator and an activity-based image analysis scheme to monitor astrocyte calcium activity in vivo. We found that different subcellular compartments (processes, somata, and endfeet) displayed distinct signaling characteristics.

Coactivation of NMDA receptors by glutamate and D-serine induces dilation of isolated middle cerebral arteries.

N-methyl-D-aspartate (NMDA) receptors are glutamate-gated cation channels that mediate excitatory neurotransmission in the central nervous system. In addition to glutamate, NMDA receptors are also activated by coagonist binding of the gliotransmitter, D-serine. Neuronal NMDA receptors mediate activity-dependent blood flow regulation in the brain.

Analysis of clusterin glycoforms in the urine of BSE-infected Fleckvieh-Simmental cows.

Currently approved tests for bovine spongiform encephalopathy (BSE) monitoring in cattle are based on the detection of the disease-related isoform of the prion protein in brain tissue and consequently are only suitable for postmortem diagnosis. Previously, to meet the demand for an antemortem test based on a matrix that would permit easy access and repeated sampling, two-dimensional differential gel electrophoresis (2D-DIGE) was used to perform an unbiased screen of bovine urine. Data demonstrated the altered abundance of particular isoforms of the multifunctional glycoprotein clusterin in urine samples obtained from BSE-infected and age-matched Fleckvieh-Simmental cattle.

A radiation-induced adaptive response prolongs the survival of prion-infected mice.

Previously, it has been demonstrated that an "adaptive response" that includes the prevention, repair, and removal of oxidative damage can be evoked by radiation at dose rates substantially lower than those at which risks have been observed. The exact pathogenic mechanism of prion diseases is unknown, but circumstantial evidence suggests that oxidative stress plays a central role. Exposure of prion-infected mice to four 500 mGy/fraction doses of (60)Co γ-radiation administered every other day at a low dose rate (0.

Efficient knockdown of human prnp mRNA expression levels using hybrid hammerhead ribozymes.

Prion diseases are invariably fatal infectious diseases of the central nervous system. The prion protein has been identified as the underlying causative agent as PrP knockout mice (prnp(0/0)) are resistant to infection. This suggests that a significant reduction in the expression levels of PrP(c) should interrupt disease progression.

The identification of disease-induced biomarkers in the urine of BSE infected cattle.

Background: The bovine spongiform encephalopathy (BSE) epidemic and the emergence of a new human variant of Creutzfeldt-Jakob Disease (vCJD) have led to profound changes in the production and trade of agricultural goods. The rapid tests currently approved for BSE monitoring in slaughtered cattle are all based on the detection of the disease related isoform of the prion protein, PrPd, in brain tissue and consequently are only suitable for post-mortem diagnosis.

Objectives: In instances such as assessing the health of breeding stock for export purposes where post-mortem testing is not an option, there is a demand for an ante-mortem test based on a matrix or body fluid that would permit easy access and repeated sampling.

Differential expression of interferon responsive genes in rodent models of transmissible spongiform encephalopathy disease.

Background: The pathological hallmarks of transmissible spongiform encephalopathy (TSE) diseases are the deposition of a misfolded form of a host-encoded protein (PrPres), marked astrocytosis, microglial activation and spongiosis. The development of powerful gene based technologies has permitted increased levels of pro-inflammatory cytokines to be demonstrated. However, due to the use of assays of differing sensitivities and typically the analysis of a single model system it remained unclear whether this was a general feature of these diseases or to what extent different model systems and routes of infection influenced the relative levels of expression.