In situ reprogramming of cardiac fibroblasts into cardiomyocytes in mouse heart with chemicals.

Cardiomyocytes are terminal differentiated cells and have limited ability to proliferate or regenerate. Condition like myocardial infarction causes massive death of cardiomyocytes and is the leading cause of death. Previous studies have demonstrated that cardiac fibroblasts can be induced to transdifferentiate into cardiomyocytes in vitro and in vivo by forced expression of cardiac transcription factors and microRNAs. Our previous study have demonstrated that full chemical cocktails could also induce fibroblast to cardiomyocyte transdifferentiation both in vitro and in vivo. With the development of tissue clearing techniques, it is possible to visualize the reprogramming at the whole-organ level. In this study, we investigated the effect of the chemical cocktail CRFVPTM in inducing in situ fibroblast to cardiomyocyte transdifferentiation with two strains of genetic tracing mice, and the reprogramming was observed at whole-heart level with CUBIC tissue clearing technique and 3D imaging. In addition, single-cell RNA sequencing (scRNA-seq) confirmed the generation of cardiomyocytes from cardiac fibroblasts which carries the tracing marker. Our study confirms the use of small molecule cocktails in inducing in situ fibroblast to cardiomyocyte reprogramming at the whole-heart level and proof-of-conceptly providing a new source of naturally incorporated cardiomyocytes to help heart regeneration.

Influential factors of surgical decompression for ulnar nerve neuropathy in Guyon's canal.

BACKGROUND: Guyon's canal syndrome is nerve compressive pathology which can lead to sensory and/or motor function deficits. This problem is usually difficult to distinguish from cubital tunnel syndrome and relatively less common than cubital tunnel syndrome. This study evaluated the functional results and patient-reported outcomes following decompression of the ulnar nerve in Guyon's canal. METHODS: Patients who were diagnosed with Guyon's canal syndrome confirmed by electrodiagnostic studies and underwent nerve decompression surgery were included in this study. The functional improvement by examining the Froment's sign, Wartenberg's sign, static two-point discrimination, and Semmes Weinstein monofilament examination as physical examination scores was evaluated. The visual analogue scale of satisfaction and the disabilities of the arm, shoulder, and hand questionnaire were used for the postoperative patient-reported outcome evaluation. RESULTS: From 2003 to 2019, 38 cases had been enrolled with a mean age of 53 years, ranging from 19 to 85 years. There were seven patients with comorbidity of diabetes mellitus and 28 patients who received additional neurolysis combined with the Guyon's release procedure. There were 19 patients with a good response to surgery and 10 patients with a poor surgical outcome due to persistent paresthesia or weakness. After statistical analysis, it was revealed that several influential factors could have been related to a compromised functional outcome, including a symptom duration of more than 3 months, combination with additional neurolysis of ipsilateral extremity, and/or comorbidity with diabetes mellitus. CONCLUSION: It was concluded that promising functional outcomes after surgical release of ulnar neuropathy in Guyon's canal could be achieved if the patients did not need additional neurolysis or the symptom duration was within 3 months.

A validated, sensitive HPLC method for the determination of trace impurities in acetaminophen drug substance.

A high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of n-propionyl-p-aminophenol, 3-chloro-4-hydroxyacetanilide, 4'-hydroxyacetophenone, 4-hydroxyacetophenone oxime, 4-acetoxyacetanilide and 4'-chloroacetanilide, the main impurities in acetaminophen drug substance. The chromatographic separation was achieved on an Eclipse XDB-18 reversed-phase column using a gradient elution, being solvent A: 0.01 M phosphate buffer at pH 3.0 and solvent B: methanol. The limit of quantitation (S/N=10:1) was 0.1 microg/ml for each impurity. The coefficients of variation were less than 4% for intra-day and inter-day analyses. The individual recovery of acetaminophen spiked samples ranged from 94 to 104% and the mean recovery for each level from 99 to 103% in the 1-150 microg/ml range for all impurities. The proposed method was successfully applied to the analyses of different lots and different manufactures of acetaminophen drug substance. The proposed method can be used for the routine quality control of acetaminophen.