Recognition and unfolding of human telomeric G-quadruplex by short peptide binding identified from the HRDC domain of BLM helicase

Research in recent decades has revealed that the guanine (G)-quadruplex secondary structure in DNA modulates a variety of cellular events that are mostly related to serious diseases. Systems capable of regulating DNA G-quadruplex structures would therefore be useful for the modulation of various cellular events to produce biological effects. A high specificity for recognition of telomeric G-quadruplex has been observed for BLM helicase. We identified peptides from the HRDC domain of BLM using a molecular docking approach with various available solutions and crystal structures of human telomeres and recently created a peptide library. Herein, we tested one peptide (BLM HRDC peptide) from the library and examined its interaction with human telomeric variant-1 (HTPu-var-1) to understand the basis of G4-protein interactions. Our circular dichroism (CD) data showed that HTPu-var-1 folded into an anti-parallel G-quadruplex, and the CD intensity significantly decreased upon increasing the peptide concentration. There was a significant decrease in hypochromicity due to the formation of G-quadruplex-peptide complex at 295 nm, which indicated the unfolding of structure due to the decrease in stacking interactions. The fluorescence data showed quenching upon titrating the peptide with HTPu-var-1-G4. Electrophoretic mobility shift assay confirmed the unfolding of the G4 structure. Cell viability was significantly reduced in the presence of the BLM peptide, with IC₅₀ values of 10.71 μM and 11.83 μM after 72 and 96 hours, respectively. These results confirmed that the selected peptide has the ability to bind to human telomeric G-quadruplex and unfold it. This is the first report in which a peptide was identified from the HRDC domain of the BLM G4-binding protein for the exploration of the G4-binding motif, which suggests a novel strategy to target G4 using natural key peptide segments.

Schematic representation of (HTPu–var-1-G4) located at the 3′ end, formation of G-quadruplex, model of the G-quadruplex structure, base stacking between G-quadruplex planes, G-quadruplex structure-peptide complex and twisting of G-quadruplex planes upon peptide binding.     

Endoscopic versus open carpal tunnel release: A short-term comparative study

Objective:

To compare the results of endoscopic carpal tunnel release (CTR) with open CTR in patients with idiopathic Carpal tunnel syndrome (CTS).

Materials and Methods:

Seventy-one patients with CTS were enrolled in a prospective randomized study from May 2003 to December 2005. All patients had clinical signs or symptoms and electro-diagnostic findings consistent with carpal tunnel syndrome and had not responded to nonoperative management. Sixty-one cases were available for follow-up. Endoscopic CTR was performed in 30 CTS patients and open CTR was performed in 31 wrists (30 patients). Various parameters were evaluated, including each patient''s symptom amelioration, complications, operation time, time needed to resume normal lifestyle and the frequency of revision surgery. All the patients were followed up for six months.

Results:

During the initial months after surgery, the patients treated with the endoscopic method were better symptomatically and functionally. Local wound problems in terms of scarring or scar tenderness were significantly more pronounced in patients undergoing open CTR compared to patients undergoing endoscopic CTR. Average delay to return to normal activity was appreciably less in group undergoing endoscopic CTR. No significant difference was observed between the endoscopic CTR group and open CTR group in regard to symptom amelioration, electromyographic testing and complications at the end of six months.

Conclusion:

Short-term results were better with the endoscopic method as there was no scar tenderness. Results at six months were comparable in both groups.     

Improved cardioprotection using a novel stepwise ischemic preconditioning protocol in rabbit heart

Background

The current commonly used cardiac ischemic preconditioning (IPC) protocol, involving three 5-min cycles of ischemia–reperfusion (I/R), may not be clinically beneficial because of its acutely deleterious effects on hemodynamics. This study attempted to assess the effects of a novel stepwise IPC scheme on cardiac function, infarct size, and arrhythmogenesis in a rabbit model of prolonged I/R.

Methods

Anesthetized open-chest rabbits were subjected to 60-min occlusion of a proximal branch of the left coronary artery followed by 180-min reperfusion. Animals were divided into five groups (n = 6 each): (1) control group (no IPC); (2) 2-min IPC group (three cycles of 2-min IPC); (3) 5-min IPC group (three cycles of 5-min IPC); (4) 10-min IPC group (three cycles of 10-min IPC); and (5) stepwise IPC group (2-, 5-, and 10-min I/R).

Results

Compared with control group, 2-, 5-, and 10-min IPC decreased arrhythmia score by 16%, 67%, and 33%, respectively. Remarkably, stepwise IPC resulted in a 78% reduction of arrhythmias. Stepwise IPC also produced the least ventricular infarct size when compared with 2-, 5-, and 10-min IPC groups (16.4% versus 39.3%, 28.1%, and 38.5%, P < 0.05).

Conclusions

These results suggest that stepwise IPC has better cardioprotective effects against prolonged I/R injury and may serve as an acceptable approach to clinical revascularization procedures on the heart, including catheter-based and surgical approaches.     

Assessing the complications and effectiveness of open carpal tunnel release in a tertiary care centre in a developing country

INTRODUCTION

Open surgical release for carpal tunnel syndrome is not devoid of complications and its quantitative assessment with the Boston questionnaire in a developing country had not been conducted, where, lack of facilities and surgical technique can influence the outcome.

PRESENTATION OF CASE

This was a prospective study in which all cases of carpal tunnel syndrome undergoing open release between June 2007 and June 2012 and who returned for follow up were included. Each patient was requested to fill out the Boston questionnaire twice both pre and post op at 3 months. All complications were recorded as well as bio-data of patients and co morbidities. Follow up was at 2 weeks and at 3 months. Those reporting complications at 3 months were further followed up until 6 months. 373 patients were included in the study. Twenty four patients developed complications. Of these, 12 experienced pain resulting from reflex sympathetic dystrophy. Three patients developed wound dehiscence, 2 cases acquired infections, 4 patients developed immediate post-operative haemorrhage and in 3 patients there was late recurrence of median nerve compression. The symptom severity score pre-operatively was 3.30 (±0.60) and it improved to 1.65 (±0.75) post-operatively indicating a significant change (p < 0.0001). The preoperative functional status score was 2.58 (±0.75) and post-op it became 1.60 (±0.80) again implying a good improvement with an effect size of 1.3.

DISCUSSION

All of the complications produced were well managed. The complication incidence was low. The open release procedure produced good improvement in hand function and in decreasing the symptom severity.

CONCLUSION

Conducting open release for carpal tunnel syndrome in a tertiary referral centre in a developing country offers a good outcome.     

Risk stratification in patients with remote prior myocardial infarction using rest-stress myocardial perfusion spect: prognostic value and impact on referral to early catheterization

BACKGROUND: Little is known about the prognostic value of myocardial perfusion single photon emission computed tomography (SPECT) in patients with remote prior myocardial infarction (MI). METHODS AND RESULTS: We identified 1413 consecutive patients with remote prior MI who underwent rest-stress myocardial perfusion SPECT. Semiquantitative visual analysis of 20 SPECT segments was used to define the summed stress, rest, and difference scores. The number of non-reversible segments was used as an index of infarct size. During follow-up (>or=1 year), 118 hard events occurred: 64 cardiac deaths (CDs) and 54 recurrent MIs. Annual CD and hard event rates increased significantly as a function of SPECT abnormality. For summed stress scores less than 4, 4 to 8, 9 to 13, and more than 13, the annual CD rates were 0.4%, 0.9%, 1.7%, and 3.5%, respectively (P =.002). Patients with small MI (<4 non-reversible segments) and no or mild ischemia (summed difference score or=4 non-reversible segments) had moderate to high annual CD rates (3.7%-6.6%) regardless of the extent of ischemia. Nuclear testing added incremental prognostic information to pre-scan information. Compared with a strategy in which all patients are referred to catheterization, a strategy that referred only those patients with a risk for CD of greater than 1% by myocardial perfusion SPECT resulted in a 41.6% cost savings. CONCLUSIONS: Myocardial perfusion SPECT adds incremental value to pre-scan information and is highly predictive and cost-efficient in the risk stratification of patients with remote prior MI. Patients with normal or mildly abnormal scan results or small MI in combination with absent or mild ischemia have a low risk for CD.     

胆管癌组织中MMP-9的表达及其意义

目的　探讨基质金属蛋白酶 9(matrixmetalloproteinase 9,MMP 9)在胆管癌发展中的作用及与胆管癌浸润、转移和预后的关系。方法　应用免疫组织化学法 (S P法 )对 5 2例经手术和病理证实的胆管癌及 10例经手术切除的正常胆管壁标本进行MMP 9蛋白检测。结果　 (1)MMP 9表达在胆管癌组织、癌旁组织及正常胆管上皮组织阳性率分别为 84 6 % (4 4 /5 2 )、2 2 6 % (7/31)和 0 %(0 /10 ) ,有显著性差异 (P <0 0 1)。 (2 )在 5 2例胆管癌组织中 ,MMP 9表达分别与肿瘤的病理分级、TNM分期、浸润和转移及手术方式有关 (P <0 0 5 ) ,而与性别、年龄、肿瘤部位及大小无关 (P >0 0 5 )。 (3)MMP 9表达阳性患者一年生存率明显低于阴性者 (P <0 0 1)。结论　MMP 9表达与胆管癌发展、浸润和转移密切相关 ,检测MMP 9的表达有助于对胆管癌转移潜能和预后的判断。     

Novel insights on the bottom–up rise strength transfer: investigating massed vs. distributed exercise training

Sport Sciences for Health - The purpose of this study is to investigate the Bottom–Up Rise Strength Transfer (BURST) induced by massed vs. distributed-rehabilitative exercise training....     

A roundtable discussion of aromatase inhibitors as therapy for breast cancer

This article summarizes the conclusions of a meeting of diverse breast cancer experts who discussed issues, controversies, and new clinical trial results relevant to the use of aromatase inhibitors for treating postmenopausal women with breast cancer. The new generation of aromatase inhibitors (anastrozole, letrozole, exemestane) have largely replaced megestrol acetate as a second-line therapy in postmenopausal women with hormone-responsive advanced breast cancer. In addition, anastrozole and letrozole have been shown to be superior to tamoxifen for first-line therapy. Finally, recent results suggest that anastrozole may be superior to tamoxifen as adjuvant therapy for early stage disease in postmenopausal women with hormone-responsive disease.