Double deficiency of cathepsin B and L in the mouse pancreas alters trypsin activity without affecting acute pancreatitis severity

BackgroundPremature intracellular trypsinogen activation has long been considered a key initiator of acute pancreatitis (AP). Cathepsin B (CTSB) activates trypsinogen, while cathepsin L (CTSL) inactivates trypsin(ogen), and both proteins play a role in the onset of AP.MethodsAP was induced by 7 hourly intraperitoneal injections of cerulein (50 μg/kg) in wild-type and pancreas-specific conditional Ctsb knockout (Ctsb^Δpan), Ctsl knockout (Ctsl^Δpan), and Ctsb;Ctsl double-knockout (Ctsb^Δpan;Ctsl^Δpan) mice. Pancreatic samples were collected and analyzed by histology, immunohistochemistry, real-time PCR, and immunoblots. Trypsin activity was measured in pancreatic homogenates. Peripheral blood was collected, and serum amylase activity was measured.ResultsDouble deletion of Ctsb and Cstl did not affect pancreatic development or mouse growth. After 7 times cerulein injections, double Ctsb and Ctsl deficiency in mouse pancreases increased trypsin activity to the same extent as that in Ctsl-deficient mice, while Ctsb deficiency decreased trypsin activity but did not affect the severity of AP. Ctsb^Δpan;Ctsl^Δpan mice had comparable serum amylase activity and histopathological changes and displayed similar levels of proinflammatory cytokines, apoptosis, and autophagy activity compared with wild-type, Ctsb^Δpan, and Ctsl^Δpan mice.ConclusionDouble deletion of Ctsb and Ctsl in the mouse pancreas altered intrapancreatic trypsin activity but did not affect disease severity and inflammatory response after cerulein-induced AP.     

基于规律成簇的间隔短回文重复序列及其相关蛋白技术检测乙型肝炎病毒共价闭合环状DNA方法的建立

目的建立一种基于规律成簇的间隔短回文重复序列及其相关蛋白(CRISPR/Cas13a)的乙型肝炎病毒(HBV)共价闭合环状DNA(HBV cccDNA)检测方法。方法提取2017年6月至2020年10月于首都医科大学附属北京佑安医院就诊的4例乙型肝炎患者肝脏总DNA后,使用HindⅢ内切酶和质粒安全性ATP依赖DNA酶(PSAD)分别进行酶切;根据松弛环状DNA(rcDNA)和cccDNA的结构差异,设计特异性扩增HBV cccDNA的引物,对酶切后的产物进行滚环扩增(RCA)和PCR扩增;并筛选crRNA,建立基于CRISPR/Cas13a技术的HBV cccDNA检测新方法。结果利用α-1-抗胰蛋白酶(A1AT)和HBV表面抗原(HBsAg)引物对双重酶切后的产物进行扩增,验证产物中HBV基因组的存在;利用HBV cccDNA和HBV rcDNA引物对PSDA酶切后的产物扩增,验证了产物中只存在HBV cccDNA;利用RCA后的阳性样本作为模板梯度稀释,然后进行PCR扩增转录后使用CRISPR/Cas13a检测,计算出检测下限为10拷贝/μl。结论本研究建立了RCA-PCR-CRISPR-Cas13a的新型检测方法,可对HBV cccDNA进行高灵敏度和高特异性检测,为乙型肝炎患者抗病毒治疗评估、治疗终点的确定以及调整治疗方案提供了有效的监测手段。     

An update in pathologic diagnosis of uterine mesenchymal tumours

Recent discovery of new disease-defining molecular alterations and development of novel targeted therapies has dramatically changed the classification and management of uterine mesenchymal neoplasms. This review discusses diagnostic updates in endometrial stromal sarcoma, PEComa, uterine tumor resembling ovarian sex cord tumor (UTROSCT), inflammatory myofibroblastic tumor, NTRK fusion uterine sarcoma, COL1A1-PDGFB fusion sarcoma, and SMARC-deficient uterine sarcoma. Key clinical, morphologic, immunophenotypic, and molecular features are reviewed, with emphasis on common differential diagnoses and pitfalls, and their impact on prognosis or management. Where applicable, the role of novel targeted therapies is discussed. A stepwise approach to uterine mesenchymal neoplasms can achieve a proper diagnosis and guide appropriate clinical management in most cases. Nonetheless, given the rarity of these tumors, their overlapping pathologic features, and rapid evolution in their classification and management, we advocate a low threshold for diagnostic consultation.     

Rats bred for low intrinsic aerobic exercise capacity link obesity with brain inflammation and reduced structural plasticity of the hippocampus

BackgroundIncreasing evidence shows obesity and poor metabolic health are associated with cognitive deficits, but the mechanistic connections have yet to be resolved. We studied rats selectively bred for low and high intrinsic aerobic capacity in order to test the association between low physical fitness, a genetic predisposition for obesity, and brain health. We hypothesized that low-capacity runner (LCR) rats with concurrently greater levels of adiposity would have increased hippocampal inflammation and reduced plasticity compared to the more physically fit high-capacity runner (HCR) rats.MethodsWe examined markers for inflammation and brain plasticity in the hippocampi of LCR rats and compared them to HCR rats. The effect of age was determined by studying the rats at a young age (8 weeks) and later in life (40 weeks). We used western blots and immunohistochemistry to quantify the expression of target proteins.ResultsOur study showed that the number of adult-born new neurons in the hippocampus was significantly lower in LCR rats than it was in HCR rats already at a young age and that the difference became more pronounced with age. The expression of synaptic proteins was higher in young animals relative to older ones. Brain inflammation tended to be higher in LCR rats than it was in the HCR rats, and more prominent in older rats than in young ones.ConclusionOur study is the first to demonstrate that low intrinsic aerobic fitness that is associated with obesity and poor metabolic health is also linked with reduced hippocampal structural plasticity at a young age. Our results also suggest that inflammation of the brain could be one factor mediating the link between obesity and poor cognitive performance.     

Synthetic MRI is not yet ready for morphologic and functional assessment of patellar cartilage at 1.5 Tesla

PurposeThe purpose of this study was to compare morphologic assessment and relaxometry of patellar hyaline cartilage between conventional sequences (fast spin-echo [FSE] T2-weighted fat-saturated and T2-mapping) and synthetic T2 short-TI inversion recovery (STIR) and T2 maps at 1.5 T magnetic resonance imaging (MRI).MethodThe MRI examinations of the knee obtained at 1.5 T in 49 consecutive patients were retrospectively studied. There were 21 men and 28 women with a mean age of 45 ± 17.7 (SD) years (range: 18–88 years). Conventional and synthetic acquisitions were performed, including T2-weighted fat-saturated and T2-mapping sequences. Two radiologists independently compared patellar cartilage T2-relaxation time on conventional T2-mapping and synthetic T2-mapping images. A third radiologist evaluated the patellar cartilage morphology on conventional and synthetic T2-weighted images. The presence of artifacts was also assessed. Interobserver agreement for quantitative variables was assessed using intraclass correlation coefficient (ICC).ResultsIn vitro, conventional and synthetic T2 maps yielded similar mean T2 values 58.5 ± 2.3 (SD) ms and 58.8 ± 2.6 (SD) ms, respectively (P = 0.414) and 6% lower than the expected experimental values (P = 0.038). Synthetic images allowed for a 15% reduction in examination time compared to conventional images. On conventional sequences, patellar chondropathy was identified in 35 patients (35/49; 71%) with a mean chondropathy grade of 4.8 ± 4.8 (SD). On synthetic images, 28 patients (28/49; 57%) were diagnosed with patellar chondropathy, with a significant 14% difference (P = 0.009) and lower chondropathy scores (3.7 ± 4.9 [SD]) compared to conventional images. Motion artifacts were more frequently observed on synthetic images (18%) than on conventional ones (6%). The interobserver agreement was excellent for both conventional and synthetic T2 maps (ICC > 0.83). Mean cartilage T2 values were significantly greater on synthetic images (36.2 ± 3.8 [SD] ms; range: 29-46 ms) relative to conventional T2 maps (31.8 ± 4.1 [SD] ms; range: 26-49 ms) (P < 0.0001).ConclusionDespite a decrease in examination duration, synthetic images convey lower diagnostic performance for chondropathy, greater prevalence of motion artifacts, and an overestimation of T2 values compared to conventional MRI sequences.     

Correlation between cow’s milk protein allergy and otitis media: a systematic review

ObjectivesTo review the evidence pertaining to the association between cow’s milk protein allergy and recurrent acute otitis media and otitis media with effusion.MethodsThe CENTRAL, Web of Science, EMBASE, MEDLINE, LILACS databases, and gray literature were searched.ResultsFour studies were included, identifying the prevalence rates: 0.2% of delayed speech due to chronic otitis media with effusion in 382 children with cow’s milk protein allergy, 10.7% of cow’s milk protein allergy in 242 children who underwent ENT procedures, 40% of cow’s milk protein allergy in 25 children with recurrent otitis media with effusion and higher tendency to otitis media in children with cow’s milk protein allergy of 186 children (1.5 + 0.6 vs. 0.4 + 0.1; p < 0.1).ConclusionConsidering the characteristics and methodological variations of the identified studies, it is not possible to state that there is reliable evidence of an association between cow’s milk protein allergy and otitis media.     

rhBMP in lumber fusion for lumbar spondylolisthesis: A systematic review and meta-analysis

Purpose

To compare the efficacy and safety of recombinant human bone morphogenetic protein (rhBMP) and iliac crest autograft in the fusion treatment of lumbar spondylolisthesis.

Modelling human pathology of traumatic brain injury in animal models

Traumatic brain injury (TBI) is caused by a head impact with a force exceeding regular exposure from normal body movement which the brain normally can accommodate. People affected include, but are not restricted to, sport athletes in American football, ice hockey, boxing as well as military personnel. Both single and repetitive exposures may affect the brain acutely and can lead to chronic neurodegenerative changes including chronic traumatic encephalopathy associated with the development of dementia. The changes in the brain following TBI include neuroinflammation, white matter lesions, and axonal damage as well as hyperphosphorylation and aggregation of tau protein. Even though the human brain gross anatomy is different from rodents implicating different energy transfer upon impact, especially rotational forces, animal models of TBI are important tools to investigate the changes that occur upon TBI at molecular and cellular levels. Importantly, such models may help to increase the knowledge of how the pathologies develop, including the spreading of tau pathologies, and how to diagnose the severity of the TBI in the clinic. In addition, animal models are helpful in the development of novel biomarkers and can also be used to test potential disease‐modifying compounds in a preclinical setting.     

Therapeutic strategies involving survivin inhibition in cancer

Survivin is a small protein that belongs to the inhibitor of apoptosis protein family. It is abundantly expressed in tumors compared with adult differentiated tissues, being associated with poor prognosis in many human neoplasms. This apoptotic inhibitor has a relevant role in both the promotion of cancer cell survival and in the inhibition of cell death. Consequently, aberrant survivin expression stimulates tumor progression and confers resistance to several therapeutic strategies in a variety of tumors. In fact, efficient survivin downregulation or inhibition results in spontaneous apoptosis or sensitization to chemotherapy and radiotherapy. Therefore, all these features make survivin an attractive therapeutic target to treat cancer. Currently, there are several survivin inhibitors under clinical evaluation, although more specific and efficient survivin inhibitors are being developed. Moreover, novel combination regimens targeting survivin together with other therapeutic approaches are currently being designed and assessed. In this review, recent progress in the therapeutic options targeting survivin for cancer treatment is analyzed. Direct survivin inhibitors and their current development status are explored. Besides, the major signaling pathways implicated in survivin regulation are described and different therapeutic approaches involving survivin indirect inhibition are evaluated. Finally, promising novel inhibitors under preclinical or clinical evaluation as well as challenges of developing survivin inhibitors as a new therapy for cancer treatment are discussed.     

A review of approaches to 18F radiolabelling affinity peptides and proteins

Affinity peptide and protein‐ (APP) based radiotracers are an increasingly popular class of radiotracer in positron emission tomography (PET), which was once dominated by the use of small molecule radiotracers. Radiolabelled monoclonal antibodies (mAbs) are important examples of APPs, yet a preference for smaller APPs, which exhibit fast pharmacokinetics and permit rapid PET aided diagnosis, has become apparent. ¹⁸F exhibits favourable physical characteristics for APP radiolabelling and has been described as an ideal PET radionuclide. Notwithstanding, ¹⁸F radiolabelling of APP is challenging, and this is echoed in the literature where a number of diverse approaches have been adopted. This review seeks to assess and compare the approaches taken to ¹⁸F APP radiolabelling with the intention of highlighting trends within this expanding field. Generic themes have emerged in the literature, namely the use of mild radiolabelling conditions, a preference of site‐specific methodologies with an impetus for short, automated procedures which produce high‐yielding [¹⁸F]APPs.