[Determination of the derivatization reactivity between α/ß-dicarbonyl compounds and standard citrullinated peptides based on matrix-assisted laser desorption ionization-time-of-flight mass spectrometry].

Protein citrullination is an irreversible post-translational modification process regulated by peptidylarginine deiminases (PADs) in the presence of Ca2+. This process is closely related to the occurrence and development of autoimmune diseases, cancers, neurological disorders, cardiovascular and cerebrovascular diseases, and other major diseases. The analysis of protein citrullination by biomass spectrometry confronts great challenges owing to its low abundance, lack of affinity tags, small mass-to-charge ratio change, and susceptibility to isotopic and deamidation interferences. The methods commonly used to study the protein citrullination mainly involve the chemical derivatization of the urea group of the guanine side chain of the peptide to increase the mass-to-charge ratio difference of the citrullinated peptide. Affinity-enriched labels are then introduced to effectively improve the sensitivity and accuracy of protein citrullination by mass spectrometry. 2,3-Butanedione or phenylglyoxal compounds are often used as derivatization reagents to increase the mass-to-charge ratio difference of the citrullinated peptide, and the resulting derivatives have been observed to contain α-dicarbonyl structures. To date, however, no relevant studies on the reactivity of dicarbonyl compounds with citrullinated peptides have been reported. In this study, we determined whether six α-dicarbonyl and two ß-dicarbonyl compounds undergo derivatization reactions with standard citrullinated peptides using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Among the α-dicarbonyl compounds, 2,3-butanedione and glyoxal reacted efficiently with several standard citrullinated peptides, but yielded a series of by-products. Phenylglyoxal, methylglyoxal, 1,2-cyclohexanedione, and 1,10-phenanthroline-5,6-dione also derivated efficiently with standard citrullinated peptides, generating a single derivative. Thus, a new derivatization method that could yield a single derivative was identified. Among the ß-dicarbonyl compounds, 1,3-cyclohexanedione and 2,4-pentanedione successfully reacted with the standard citrullinated peptides, and generated a single derivative. However, their reaction efficiency was very low, indicating that the ß-dicarbonyl compounds are unsuitable for the chemical derivatization of citrullinated peptides. The above results indicate that the α-dicarbonyl structure is necessary for realizing the efficient and specific chemical derivatization of citrullinated peptides. Moreover, the side chains of the α-dicarbonyl structure determine the structure of the derivatives, derivatization efficiency, and generation (or otherwise) of by-products. Therefore, the specific enrichment and precise identification of citrullinated peptides can be achieved by synthesizing α-dicarbonyl structured compounds containing affinity tags. The proposed method enables the identification of citrullinated proteins and their modified sites by MS, thereby providing a better understanding of the distribution of citrullinated proteins in different tissues. The findings will be beneficial for studies on the mechanism of action of citrullinated proteins in a variety of diseases.

Risk Factors of Difficult Pharyngeal Accidental Fishbones Ingestion.

OBJECTIVE: Accidental pharyngeal fishbone ingestion is a common complaint in ear, nose, and throat clinics. Approximately two-thirds of the accidentally ingested fishbones can be removed using tongue depressors and indirect laryngoscopy. However, the remaining third is challenging to identify and remove using these methods. These difficult fishbones require identification and removal via more advanced approaches. Video-guided laryngoscope is used to deal with difficult fishbones in our center. This study aimed to explore the risk factors for difficult fishbones. METHODS: A prospective study was performed at a teaching hospital on 2080 patients. Univariate and multivariate analyses were performed to identify the risk factors. RESULTS: The common fishbone locations were the tonsils (39.8%; defined as STEP-I), tongue base (37.1%), vallecula (13.3%; STEP-II), and hypopharynx (9.8%; STEP-III). With increasing STEP level, the ratio of difficult fishbones correspondingly increased (Z = 13.919, P < .001), and the proportions were 21.1%, 41.9%, and 70% in STEP-I, II, and III, respectively. In particular, fishbones in STEP-III (vs STEP-I) had a higher risk of difficult fishbones (odds ratio [OR]: 11.573, 95% CI: 7.987-16.769). Complaints of neck pain (yes vs no), foreign body sensation (yes vs no), and shorter length of fishbones always had a lower risk of difficult fishbones (OR: 0.455, 95% CI: 0.367-0.564; OR: 0.284, 95% CI: 0.191-0.422; OR: 0.727, 95% CI: 0.622-0.85). Missing teeth (yes vs no), swallowing behavior after fishbone ingestion (yes vs no), and male patients (vs female) had a higher risk of difficult fishbones (OR: 1.9, 95% CI: 1.47-2.456; OR: 1.631, 95% CI: 1.293-2.059; OR: 1.278, 95% CI: 1.047-1.56). CONCLUSIONS: Neck pain, foreign body sensation, fishbone length, patient age and sex, tooth status, and swallowing behavior after fishbone ingestion are independent risk factors for difficult fishbones.

Increased Cerebrospinal Fluid Uric Acid Levels in Guillain-Barré Syndrome.

Uric acid (UA) is a natural scavenger for peroxynitrite and can reflect antioxidant activity and oxidative stress in several neurological disorders. Changes in serum and cerebrospinal fluid (CSF) levels of UA have been reported in patients with multiple sclerosis and neuromyelitis optica spectrum disorders. The levels of UA in CSF are relatively poorly understood in patients with Guillain-Barré syndrome (GBS). It remains unclear whether UA can play an antioxidant role and reflect oxidative stress in GBS. The purpose of this study is to investigate CSF and serum UA levels in patients with GBS and their relationship with clinical characteristics. The CSF and serum UA levels were detected in 43 patients with GBS, including 14 acute inflammatory demyelinating polyneuropathy (AIDP), 6 acute motor axonal neuropathy (AMAN), 13 with acute motor and sensory axonal neuropathy (AMSAN), 7 Miller Fisher syndrome (MFS), and 3 unclassified, and 25 patients with non-inflammatory neurological disorders (NIND) as controls. Moreover, serum UA levels were also detected in 30 healthy controls. The levels of UA were measured using uricase-based methods with an automatic biochemical analyzer. CSF UA levels were significantly increased in patients with GBS (p = 0.011), particularly in patients with AIDP (p = 0.004) when compared with NIND. Among patients with GBS, CSF UA levels were higher in those with demyelination (p = 0.022), although the difference was not significant after multiple testing correction. CSF UA levels in GBS were positively correlated with serum UA levels (r = 0.455, p = 0.022) and CSF lactate (r = 0.499, p = 0.011). However, no significant correlations were found between CSF UA levels and GBS disability scores. There were no significant differences in serum UA levels among GBS, NIND, and healthy controls. These results suggest that CSF UA may be related to the pathogenesis of demyelination in patients with GBS and may be partially determined by serum UA and the impaired blood-nerve barrier.

PIWI-like protein 1 upregulation promotes gastric cancer invasion and metastasis.

BACKGROUND: PIWI-like protein 1 (PIWIL1) is an important member of the Argonaute protein family and is closely related to the malignant behaviors of tumor cells. This study aimed to investigate the relationship between PIWIL1 and gastric cancer (GC). METHODS: We investigated PIWIL1 expression status in GC tissues as well as its association with clinicopathological characteristics and prognosis of GC patients. PIWIL1 siRNA was transfected into a GC cell line to elucidate its impact on malignant biological behavior. RESULTS: The results showed that PIWIL1 was upregulated in GC tissues and correlated with tumor differentiation, lymph node status, and TNM stage. The high PIWIL1 expression was an independent predictor for the prognosis of patients with GC. Silencing of PIWIL1 expression in GC cell lines suppressed tumor cell proliferation, migration, and invasion. CONCLUSION: High PIWIL1 expression suggests a poor prognosis for GC patients and PIWIL1 can serve as an important molecular marker for predicting the prognosis of GC patients.

Expression Status of PIWIL1 as a Prognostic Marker of Colorectal Cancer.

The PIWI-like protein 1 (PIWIL1) plays a crucial role in stem cell proliferation, embryogenesis, growth, and development, as well as differentiation and maturation in multiple organisms. The relationships between PIWIL1 expression and clinicopathological features of colorectal cancer (CRC) patients were analyzed by us. Survival analysis was performed using the Kaplan-Meier method and Cox's proportional hazards model. The high expression rate of PIWIL1 in the cancer tissue was obviously higher than that in the corresponding adjacent tissue. The expression of PIWIL1 was closely related to the tumor differentiation degree, infiltration depth, lymphovascular invasion, lymph node metastasis, and TNM stage. The Kaplan-Meier survival model suggested that the survival time of CRC patients in the high PIWIL1 expression group was notably lower than that in the low PIWIL1 expression group. High PIWIL1 expression suggests a poor prognosis for CRC patients, and PIWIL1 can serve as an important molecular marker for predicting the prognosis of CRC patients.

Increased resistin levels in the serum and cerebrospinal fluid of patients with neuromyelitis optica.

INTRODUCTION: Resistin, which acts as a pro-inflammatory cytokine, has been implicated in the pathogenesis of several autoimmune diseases. However, the involvement of resistin in neuromyelitis optica (NMO), a severe inflammatory central nervous system disorder that targets the optic nerve and spinal cord, remains unclear. METHODS: We measured serum and cerebrospinal fluid (CSF) resistin levels in patients with NMO and controls matched by age and sex. The link between resistin levels and clinical variables in NMO was subsequently assessed. RESULTS: The concentrations of serum and CSF resistin were significantly higher in patients with NMO than in controls, and decreased following treatment with methylprednisolone. High sensitivity C-reactive protein (hs-CRP) levels and annualized relapse rate positively correlated with resistin levels in patients with NMO. CONCLUSION: Resistin might be a useful biomarker of inflammation in NMO, and a potential target for the treatment of NMO.

Effect of calcium dobesilate combined with panretinal photocoagulation on severe non-proliferative diabetic retinopathy patients / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM: To study the effect of calcium dobesilate combined with panretinal photocoagulation on severe non-proliferative diabetic retinopathy patients (NPDR). ·METHODS:A total of 92 patients (184 eyes) with severe NPDR were collected in our hospital from December 2014 to April 2017, and divided into laser group and combined treatment group by random number table method. The laser group was treated with panretinal laser photocoagulation, and the combined treatment group received calcium dobesilate combined with retinal laser photocoagulation. The effect of the two groups was compared on the retinal microcirculation parameters. · RESULTS: Seven weeks after treatment, treatment effective rate in combined treatment group was higher than that in laser group (P<0.01). Fundus examination parameter such as Ops OS2, subfoveal choroid thickness (SFCT) in combined treatment group were higher than those in laser group (P<0.01). Retinal microcirculation parameters such as PSV, MV in combined treatment group were higher than the level of the laser group,RI,PI levels were lower than those in laser group (P<0.01). · CONCLUSION: Calcium dobesilate combines with panretinal photocoagulation in severe NPDR patients can effectively improve the overall effect and optimize the fundus structure and retinal microcirculation.