Πέμπτη 16 Φεβρουαρίου 2023

In vivo PIWI slicing in mouse testes deviates from rules established in vitro [LETTER TO THE EDITOR]

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Argonautes are small RNA-binding proteins, with some having small RNA-guided endonuclease (slicer) activity that cleaves target nucleic acids. One cardinal rule that is structurally defined is the inability of slicers to cleave target RNAs when nucleotide mismatches exist between the paired small RNA and the target at the cleavage site. Animal-specific PIWI clade Argonautes associate with PIWI-interacting RNAs (piRNAs) to silence transposable elements in the gonads, and this is essential for fertility. We previously demonstrated that purified endogenous mouse MIWI fails to cleave mismatched targets in vitro. Surprisingly, here we find using knock-in mouse models that target sites with cleavage-site mismatches at the 10th and 11th piRNA nucleotides are precisely sliced in vivo. This is identical to the slicing outcome in knock-in mice where targets are base-paired perfectly with the piRNA. Additionally, we find that pachytene piRNA-guided slicing in both these situations failed to initiate phased piRNA production from the specific target mRNA we studied. Instead, the two slicer cleavage fragments were retained in PIWI proteins as pre-piRNA and 17–19 nt by-product fragments. Our results indicate that PIWI slicing rules established in vitro are not respected in vivo, and that all targets of PIWI slicing are not substrates for piRNA biogenesis.

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Incidence of Postoperative CSF Leaks in Class III Obese Patients Undergoing Middle Cranial Fossa Approach for Spontaneous CSF Leak Repair

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imageObjective To determine the safety and effectiveness of the middle cranial fossa (MCF) approach for spontaneous cerebrospinal fluid leak (sCSF-L) repair in class III obese patients. To also assess the need for prophylactic lumbar drain (LD) placement in this patient population. Study Design Retrospective cohort study. Setting Tertiary Academic Center. Patients All patients older than 18 years undergoing sCSF-L repair with an MCF approach. Intervention An MCF craniotomy for sCSF-L repair. Main outcome measure Rate of complications and postoperative leaks. Results There were no perioperative complications in 78.9% (56/71) of cases. The surgical complication rate was 12.5% (2/16), 10% (2/20), and 22.2% (6/27) in class I, class II, and class III obese patients. There was no statistically significant difference in complications among these three groups. The most common postoperative complication was a persistent CSF leak in the acute postoperative period with an overall rate of 9.9% (7/71) with six of the seven patients requiring postoperative LD placement. The percentage of postoperative CSF leaks in nonobese, class I, class II, and class III patients were 25% (2/8), 12.5% (2/16), 0% (0/20), and 11.1% (3/27), respectively. There was no statistically significant difference in the rate of postoperative CSF leaks among the four groups (chi-square, p = 0.48). In all cases, the acute postoperative CSF leaks resolved in the long term and did not require further surgical repair. Conclusions We determine that MCF craniotomy repair for sCSF-Ls is safe in patients with class III obesity, and the incidence of postoperative CSF leaks did not vary among other obesity classes. We also find that prophylactic placement of LDs is not routinely needed in this population.
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Surface Electromyography-Based Analysis of the Lower Limb Muscle Network and Muscle Synergies at Various Gait Speeds

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Gait movement is an important activity in daily human life. The coordination of gait movement is directly affected by the cooperation and functional connectivity between muscles. However, the mechanisms of muscle operation at different gait speeds remain unclear. Therefore, this study addressed the gait speed effect on the changes in co operative modules and functional connectivity between muscles. To this end, surface electromyography (sEMG) signals were collected from eight key lower extremity muscles of twelve healthy subjects walking on a treadmill at high, middle, and low motion speeds. Nonnegative matrix factorization (NNMF) was applied to the sEMG envelope and intermuscular coherence matrix, yielding five muscle synergies. Muscle functional networks were constructed by decomposing the intermuscular coherence matrix, revealing different layers of functional muscle networks across frequencies. In addition, the coupling strength between cooperative muscles grew with gait speed. Different coordination patterns among muscles with changes in gait speed related to the neuromuscular system regulation were identified.
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Fasting Plasma Glucose Increase and Neutrophil-to-Lymphocyte Ratio as Risk Predictors of Clinical Outcome of COVID-19 Pneumonia in Type 2 Diabetes Mellitus

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Exp Clin Endocrinol Diabetes
DOI: 10.1055/a-2009-6937

Aim of the study To evaluate fasting plasma glucose (FPG) increase and neutrophil-to-lymphocyte ratio (NLR) as risk predictors of severe clinical outcome of COVID-19 pneumonia in type 2 diabetes mellitus (T2DM) hospitalised patients. Patients and methods Type 2 diabetes mellitus (T2DM) patients hospitalised between March 2020 and February 2021 were studied retrospectively. The NLR ratio at admission and FPG increase (day 7, day with maximal FPG) were evaluated in association with the clinical progression of SARS-CoV-2 infection. Results Three hundred patients (165 men, 135 women) were included in the study. The mean age was 67.17±8.65 years. Severe COVID-19 pneumonia was diagnosed in 170 patients (56.7%). Fifty-four patients (18%) were intubated and 49 (16.3%) died. Greater increase in FPG (79.5 vs. 44.5 mg/dL for day 1–7, p<0.001; and 113.5 vs. 75 mg/dL for day 1-day with maximum glucose value, p<0.001) and higher NLR at admission (10.65 vs. 6.85) were seen in patients with need of high-flow oxygen compared to those without need, and they were associated with a higher probability of intubation and death. Conclusion FPG increase and NLR could be significant risk predictors of severe COVID-19 pneumonia in T2DM hospitalised patients.
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Article in Thieme eJournals:
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Magnetic Resonance Imaging Virtual Biopsy of Common Solid Renal Masses—A Pictorial Review

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imageThe expanded application of radiologic imaging resulted in an increased incidence of renal masses in the recent decade. Clinically, it is difficult to determine the malignant potential of the renal masses, thus resulting in complex management. Image-guided biopsies are the ongoing standard of care to identify molecular variance but are limited by tumor accessibility and heterogeneity. With the evolving importance of individualized cancer therapi es, radiomics has displayed promising results in the identification of tumoral mutation status on routine imaging. This article discusses how magnetic resonance imaging features can guide a radiologist toward identifying renal mass characteristics.
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