Pore-Forming Cardiotoxin VVA2 (Volvatoxin A2) Variant I82E/L86K Is an Atypical Duplex-Specific Nuclease

VVA2 (volvatoxin A chain 2) is a cardiotoxic protein purified from Volvariella volvacea. Its biological activities include hemolysis, writhing reaction, neurotoxicity, and ventricular systolic arresting activity. The cytotoxicity of VVA2 was mainly considered due to its pore-forming activity. Here we report a novel biological activity of its variants VVA2 I82E/K86K as a duplex-specific nuclease. Recombinant VVA2 variant I82E/L86K (Re-VVA2 I82E/L86K), deprived of the oligomerization property, shows increased nuclease activity compared to VVA2. Re-VVA2 I82E/L86K converts supercoiled DNA (Replicative form I, RF I) into nicked form (RF II) and linear form (RF III) in the presence of Mg²⁺ or Mn²⁺. Besides plasmid DNA, it also exhibits nuclease activity on E. coli genomic DNA rather than ssDNA or RNA. Re-VVA2 I82E/L86K preferentially cleaves dG-dC-rich dsDNA regions and shows the best performance at pH 6–9 and 55 °C. Our structure–function study has revealed amino acid E111 may take an active part in nuclease activity through interacting with metal ions. Based on the sequences of its cleavage sites, a “double-hit” mechanism was thereby proposed. Given that Re-VVA2 I82E/L86K did not exhibit the conserved nuclease structure and sequence, it is considered an atypical duplex-specific nuclease.     

Apathy and impulsiveness in Parkinson disease: Two faces of the same coin?

Apathy and impulsiveness are 2 common non-motor symptoms in Parkinson disease that could occur in different periods or simultaneously. Apathy and impulsiveness could be interpreted as opposite extremes of a spectrum of motivated behavior dependent on dopaminergic dysfunction, in which, impulsivity, is a result of a hyperdopaminergic state, whereas apathy is viewed as a hypodopaminergic. The study aimed to investigate the presence of impulsiveness and other neuropsychiatric symptoms in Parkinson disease patients with apathy symptoms.Eighty-one patients with Parkinson disease were enrolled in this retrospective study. All subjects were evaluated by the Italian version of the Dimensional Apathy Scale and the Barratt Impulsiveness Scale-version 11, to assess, respectively, apathy and impulsiveness; they were divided into 2 groups (apathy and no apathy). All patients were administered also with questionnaires assessing depressive and anxious symptoms.Statistical analyses showed relevant results. In no-apathy group, education was a significant predictor on impulsiveness (attentional and motor) and apathy (executive and emotional); depression was a significant predictor on planning impulsivity and apathy.This study aimed to consider the importance of apathy and impulsivity in Parkinson disease. Although these are considered as opposite extremes of a spectrum of motivated behavior dependent on dopaminergic dysfunction, these can also occur separately. Moreover, several variables could represent important predictors of apathy and impulsiveness, such as depression. Future investigations should deepen the role of other demographics and psychological variables.     

Endoscopic stenting for malignant biliary obstruction

Use of endoscopic stents to manage patients with malignant obstructive jaundice is a well accepted measure. Interpretation of the results of endoscopic stenting must be made with reference to the level of the bile duct obstruction. Results were generally unsatisfactory for hilar lesions, especially when the intrahepatic ducts were segregated into multiple isolated systems. After deployment, stent dysfunction due to clogging by biliary sludge is apparently an inevitable process for the conventional plastic stent. Considerable efforts had been made to prolong the stent patency by changing its physical configuration, coating the inner lumen, and the choice of material but with little success. The development of a self-expandable metal stent is a major advance, but the benefits derived from a larger stent lumen are compromised by the initial expense and the tumor ingrowth through the wires for all models available commercially. Current data failed to substantiate the value of routine preoperative biliary decompression, as there is no reduction in the morbidity and mortality rates after surgery. Although biased patient selection may have resulted in the negative observations made, repeated clinical trials should probably focus on patients with distal bile duct tumors who are preparing for a major pancreatic resection. As a definitive palliative measure, endoscopic stenting is a more cost-effective option than surgery for patients with limited life expectancy based on data regarding plastic stents. The recommendations are evolving however, as there is progressive refinement of laparoscopic surgery techniques and designs of endoscopic stents.     

Decreased growth velocity before IDDM onset

Diabetes can retard growth. Growth was studied prospectively in 12 nondiabetic identical twins aged less than 14 yr and in their co-twins with insulin-dependent diabetes mellitus (IDDM) to determine whether changes in growth occur before the onset of IDDM. Seven of the 12 nondiabetic twins subsequently developed IDDM; the remainder are now unlikely to become diabetic. A significantly reduced growth velocity was observed more frequently in the nondiabetic twins (7 of 12) than in their diabetic co-twins (1 of 12; P = 0.03). Of the 7 nondiabetic twins who were prediabetic, 6 had a reduction in growth velocity to below the 3rd percentile before the onset of diabetes compared with 1 of their diabetic co-twins (P = 0.03). However, only 1 of the 5 nondiabetic twins who did not develop diabetes showed a reduction in growth velocity. The nadir of growth in the twins who developed diabetes occurred a mean of 1.2 yr before diagnosis (range 0.3-2.3 yr). All 7 of the prediabetic twins had islet cell antibodies when first seen, and 3 had them before they showed either decreased growth velocity or impaired glucose tolerance. In 4 prediabetic twins, the decreased growth preceded impaired glucose tolerance. The prediabetic twins tested had lower testosterone or estradiol levels at the time they showed decreased growth than their diabetic twins. We conclude that decreased growth velocity is an early sensitive marker of IDDM.     

Identification of novel biomarkers differentially expressed between African-American and Caucasian-American prostate cancer patients

Prostate cancer (PCa) incidence and mortality rate vary among racial and ethnic groups with the highest occurrence in African American (AA) men who have mortality rates twice that of Caucasians (CA). In this study, we focused on differential expression of proteins in AA prostate cancer compared to CA using Protein Pathway Array Analysis (PPAA), in order to identify protein biomarkers associated with PCa racial disparity. Fresh frozen prostate samples (n=90) obtained from radical prostatectomy specimens with PCa, including 25 AA tumor, 21 AA benign, 23 CA tumor, 21 CA benign samples were analyzed. A total of 286 proteins and phosphoproteins were assessed using PPAA. By PPAA analysis, 33 proteins were found to be significantly differentially expressed in tumor tissue (n=48, including both CA and AA) in comparison to benign tissue (n=42). We further compared protein expression levels between AA and CA tumor groups and found that 3 proteins were differentially expressed (P<0.05 and q<5%). Aurora was found to be significantly increased in AA tumors, while Cyclin D1 and HNF-3a proteins were downregulated in AA tumors. Predicted risk score was significantly different between AA and CA ethnic groups using logistic regression analysis. In conclusion, we identified Aurora, Cyclin D1 and HNF-3a proteins as being differentially expressed between AA and CA in PCa tissue. Our study suggests that these proteins might be involved in different pathways that lead to aggressive PCa behavior in AA patients, potentially serving as biomarkers for the PCa racial disparity.     

急性胰腺炎血流动力学变化及多巴胺治疗

作者观察了胰管内注射胰蛋白酶和胆汁所致犬急性胰腺炎(AP)时血流动力学变化及多巴胺对 AP 的治疗作用。治疗组在制 AP 模型后10min 开始静脉持续3h 滴注多巴胺,持续3h,每小时0.6mg/kg。AP 组的胰腺血流量(PBF)在制 AP 后迅速下降,全身血流动力学也发生了明显改变。多巴胺治疗可增加 PBF,改善全身血流动力学,降低 AP 犬的死亡率和减轻胰腺炎程度。提示多巴胺可通过改善 AP 早期的胰血供,有效地阻止水肿性胰腺炎向出血坏死性胰腺炎发展。     

Effect of IL-6 C-572G polymorphism on idiopathic membranous nephropathy risk in a Han Chinese population

Membranous glomerulonephritis (MGN) is viewed as an immune-mediated glomerular disease, with immunologic expression occurring in genetically susceptible persons. The cytokine interleukin-6 (IL-6) gene polymorphism is known to impair intracellular signaling pathways following adaptive immune response. Our study gauged the effects of IL-6 C-572G (rs1800796) single nucleotide polymorphism (SNP) on MGN among Taiwan's Han Chinese population, as analyzed in 265 controls and 106 MGN patients. Genotyping for IL-6 C-572G SNP was performed by restriction fragment length polymorphism assay. Data showed stark differences in genotype and allele frequency distributions at IL-6 C-572G SNP between MGN patients and controls (p = 1.6E-04 and 1.7E-04, respectively). People with C allele or with CC genotype at IL-6 C-572G SNP showed higher risk of MGN (odds ratio = 2.42 and 2.71, respectively; 95% confidence interval = 1.51-3.87 and 1.60-4.60, respectively). These point to IL-6 C-572G polymorphism as the underlying cause of MGN; polymorphism merits further investigation.     

Outpatient and short-stay thyroid surgery

With the realization that simple thyroid procedures had a very low rate of complication and that patients often seemed well enough to go home from the recovery room, we began performing them in an ambulatory surgery setting. We review here 134 consecutive thyroid procedures performed at Columbia Presbyterian Medical Center between July 1987 and July 1989. Patients undergoing reoperation, neck dissection, sternal splits, or other concomitant procedures were excluded. There were 105 women and 29 men with an average age of 47 years. Fifty percent of the operations were performed for benign disease, although the most common diagnosis was papillary cancer (44%). Twenty-one operations (16%) were performed under local anesthesia. Most patients underwent surgery in our ambulatory surgery unit and 76 were discharged the day of surgery. Of these patients, 21 underwent total thyroidectomy, 13 subtotal thyroidectomy, and 42 simple thyroid lobectomy. Of the 58 patients who were admitted, 53 were discharged on the day following surgery. The average length of stay was 0.49 days. Extensive pre- and postoperative teaching was given regarding the signs and symptoms associated with the complications of thyroid surgery. All patients were felt to be reliable and capable of understanding the procedure and of complying with the postoperative plans. Postoperative complications included 8 patients (6%) with transient hypocalcemia and 1 patient (0.75%) with permanent unilateral recurrent laryngeal nerve paralysis. All complications occurred in patients who underwent total thyroidectomies. No patient had a postoperative complication requiring reoperation or readmission. We conclude that by using specific selection criteria, thyroid lobectomies and subtotal thyroidectomies can be performed safely in an ambulatory surgery setting without increase in morbidity or mortality.