Basic protein- and peptide-induced stabilization of long-loop DNA G-guadruplexes.

The human genome contains many G-quadruplex-forming sequences, including sequences containing long single-stranded loops that are believed to be unfavorable for G-quadruplex formation. The intracellular environment of biological cells is crowded with proteins with charged surfaces. Understanding the effects of protein-rich environments is important for understanding the formation of G-quadruplexes in an intracellular environment. In this study, we investigated the structural stability of DNA G-quadruplexes in the presence of several types of globular proteins (lysozyme, cytochrome c, bovine serum albumin, myoglobin, histone proteins, and serum proteins), unstructured polypeptides (protamine and poly-l-lysine), and oligopeptides (RGG/RG-domain peptides and short repeated peptides). Thermal melting studies of G-quadruplex-forming oligonucleotides derived from the human telomeric repeat sequence revealed that environments containing high concentrations of proteins and peptides differently affected the G-quadruplex stability according to their loop lengths. We found that weak electrostatic interactions of G-quadruplex loops with basic proteins and peptides improved the stability of long-loop G-quadruplexes and the interactions were strengthened under crowded conditions simulated by dextran. The comparison of the effects of different types of proteins and peptides indicated that excluded volume interactions and structural flexibility of both DNA and polypeptide chains influenced the efficiency of their interactions. This study provides insights into long-loop G-quadruplex stability in a crowded intracellular environment and the recognition of G-quadruplexes by arginine-rich domains of G-quadruplex-binding proteins.

[Complications and Proposed Preventive Measure of Holumium Laser Enucleation of the Prostate during the Initial Phase at Our Hospital].

Clinical charts of 95 patients who underwent holmium laser enucleation of the prostate (HoLEP) between May 2012 and January 2016 were reviewed for complications and their causative factors, as well as treatment outcomes. Of 23 intraoperative complications and 3 cases of prolonged post prostatectomy incontinence, 23 incidents (89%) occurred within the initial 20 cases performed by each surgeon. The details of the intraoperative complications were : bladder injury, 6 (6.3%) ; perforation at 6 o'clock beneath the bladder neck, 2 (2.1%) ; capsular perforation, 4 (4.2%) ; and equipment failure, 9 (9.5%). Bladder injury and capsular perforation resulted frompoor hemostasis, while perforation beneath the bladder neck resulted fromforceful retrograde dissection under disorientation. Excessive tension in the external sphincter during retrograde dissection, but not antegrade, could lead to prolonged incontinence. HoLEP improved bladder outlet obstruction subjectively and objectively. During the initial phase of HoLEP, adequate hemostasis and meticulous plane dissection at the bladder neck and antegrade dissection at the apical portions are of paramount importance to prevent significant surgical complications.

Lumbar Degenerative Spondylolisthesis: Changes in Surgical Indications and Comparison of Instrumented Fusion With Two Surgical Decompression Procedures.

STUDY DESIGN: Single-center retrospective case series. OBJECTIVE: To compare outcomes of instrumented fusion and two methods of decompression for degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: There is no consensus on the surgical indications or optimum techniques for lumbar degenerative spondylolisthesis. METHODS: We analyzed the data of 140 patients treated by fusion (n = 80; mean follow-up, 77.9 months) or decompression (n = 60; mean follow-up, 38.0 months) and examined changes in surgical indications over a 12-year period. We compared the outcomes of instrumented fusion with the outcomes of two decompression techniques, the first employing a unilateral approach for bilateral decompression and the second employing a bilateral approach for contralateral decompression, with contralateral foraminal decompression as needed. Postoperative evaluation was made at the final follow-up visit beginning in 2007 by analyzing patient interviews and neurological examination data. We compared results with the Japanese Orthopedic Association symptom score before surgery and at final follow-up. RESULTS: Surgical indications for fusion narrowed over time, with fusion used less frequently and decompression used more frequently. Similar decreases in clinical symptoms, including low back pain, were achieved with all methods. In the decompression groups, preoperative slip distance and instability, and postoperative slip progression or development of instability, did not correlate significantly with clinical outcome. Slip progression occurred in 8 of 10 levels in patients with preoperative translation ≥5 mm, but these patients showed no increase in instability, defined as translation ≥ 2 mm, at final follow-up. CONCLUSION: Our findings raise a question about the value of the radiologic criteria for performing fusion used in the late period, namely translation ≥5 mm and/or rotation ≥ 10°. If discogenic pain is excluded, decompression alone may be suitable even for patients with severe low back pain and translation ≥5 mm. LEVEL OF EVIDENCE: 4.

The role of glutathione on the cytotoxic effects and cellular uptake of diphenylarsinic acid, a degradation product of chemical warfare agents.

The mechanism underlying enhancement of the cytotoxic effects of diphenylarsinic acid (DPAA) by sulfhydryl (SH) compounds, such as glutathione (GSH) and dimercaptopropane sulfonate (DMPS), was investigated in terms of not only the effects of SH compounds on DPAA uptake by cells, but also the cytotoxic effects of the GSH adduct of DPAA, DPA-GS. In addition, the cytotoxic effects of DPA-GS and cellular uptake were investigated in conjunction with the effects of GSH depletion. Cells took up DPAA in a time- and temperature-dependent manner for up to 2 h, then the uptake leveled off for 6 h. Arsenic species other than DPAA were not detected in the cells. The presence of GSH and DMPS did not influence the rate of uptake of DPAA by the cells. By contrast, when the cytotoxic potential of DPA-GS was compared with that of DPAA, DPA-GS was about 1,000 times more toxic than DPAA, suggesting that enhancement of DPAA toxicity by SH compounds might be due to the formation of adducts in the culture medium. The cytotoxic effects of DPA-GS were suppressed markedly by the presence of GSH and DMPS, and the suppression was attributed to an inhibition of more than 90% by the SH compounds of DPA-GS uptake. Depletion of cell GSH enhanced the cytotoxic effects of DPA-GS by two to three times and the enhancement attributed to an increased cellular uptake of DPA-GS. These results suggest that GSH plays a role in regulating the formation of DPA-GS and cellular uptake.