Role of helicity of α-helical antimicrobial peptides to improve specificity

A major barrier to the use of antimicrobial peptides as antibiotics is the toxicity or ability to lyse eukaryotic cells. In this study, a 26-residue amphipathic α-helical antimicrobial peptide A12L/A20L (Ac-KWKSFLKTFKSLKKTVLHTLLKAISS-amide) was used as the framework to design a series of D- and L-diastereomeric peptides and study the relationships of helicity and biological activities of α-helical antimicrobial peptides. Peptide helicity was measured by circular dichroism spectroscopy and demonstrated to correlate with the hydrophobicity of peptides and the numbers of D-amino acid substitutions. Therapeutic index was used to evaluate the selectivity of peptides against prokaryotic cells. By introducing D-amino acids to replace the original L-amino acids on the non-polar face or the polar face of the helix, the hemolytic activity of peptide analogs have been significantly reduced. Compared to the parent peptide, the therapeutic indices were improved of 44-fold and 22-fold against Gram-negative and Gram-positive bacteria, respectively. In addition, D- and L-diastereomeric peptides exhibited lower interaction with zwitterionic eukaryotic membrane and showed the significant membrane damaging effect to bacterial cells. Helicity was proved to play a crucial role on peptide specificity and biological activities. By simply replacing the hydrophobic or the hydrophilic amino acid residues on the non-polar or the polar face of these amphipathic derivatives of the parent peptide with D-amino acids, we demonstrated that this method could have excellent potential for the rational design of antimicrobial peptides with enhanced specificity.

Preliminary study of assessment of mental health level among oral tumor patients and difference of relevant material basis / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the difference in mental health status of oral tumor patients and their spouses, and explore the differences on the basis of relevant materials.</p><p><b>METHODS</b>Forty patients with oral cancer, eighteen spouses, and thirty-five patients with oral benign tumor were diagnosed in the West China Hospital of Stomatology between December 2011 and August 2012 and assessed with symptom checklist-90 (SCL90) (the 5-grade scoring). Participants were assessed independently according to their conditions. Blood samples were obtained from the participants by syringe on the second admission day. A method was developed to determine the concentrations of catecholamine and glucocorticoid in the serum using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).</p><p><b>RESULTS</b>The scores for compel, depression and rests in the cancer group and benign tumor group were statistically significant (P<0.05). The scores for compel, dread and stubborn in the cancer group and their spouses were statistically significant (P<0.05). The differences between the total and other monomial factor scores were not statistically significant. However, the contents of epinephrine, norepinephrine, cortisone and hydrocortisone in the serum, as determined by HPLC-MS/MS, were significantly different (P<0.001).</p><p><b>CONCLUSION</b>Psychiatric factors do not show a simple factor effect on patients. Symptoms of patients may be based on tumorigenesis and developed in small molecules. Further research is required.</p>

Experience of improving the quality of neonatal hearing screening / 中国基层医药

Objective To investigate the measures to improve the newborn hearing screening quality.Methods835 cases of neonates using distortion product otoacoustic emissions for hearing screening,after first,second and third hearing screening,the final 5 cases failed,diagnosed by ABR screening hearing handicap in 3 cases.Experience constantly was summed up during screening process to improve screening quality.Results835 newborns were screened.The rate of failing to hearing screening was 0.60％,the rate of hearing impairment diagnosed by ABR was 0.36％,and the positive proportion of hearing screening was 0.24％.ConclusionOur experience during screening progress is to take some measures to improve the newborn hearing screening quality,with reducing false positives and avoiding false negatives,by choosing screening time,cleaning external ear and electric-otoscopy examination,environmental noise control,updating test procedures according to the physiology and development of the newborns,testing calibration instruments of otoacoustic emissions hearing screening,selecting suitable earplug,probe with correct plsce,and combining acoustic impedance examination,with a long term follow-up of listening in high risk neonates with passing screening.

Alpha-helical cationic antimicrobial peptides: relationships of structure and function

Antimicrobial peptides (AMPs), with their extraordinary properties, such as broad-spectrum activity, rapid action and difficult development of resistance, have become promising molecules as new antibiotics. Despite their various mechanisms of action, the interaction of AMPs with the bacterial cell membrane is the key step for their mode of action. Moreover, it is generally accepted that the membrane is the primary target of most AMPs, and the interaction between AMPs and eukaryotic cell membranes (causing toxicity to host cells) limits their clinical application. Therefore, researchers are engaged in reforming or de novo designing AMPs as a 'single-edged sword' that contains high antimicrobial activity yet low cytotoxicity against eukaryotic cells. To improve the antimicrobial activity of AMPs, the relationship between the structure and function of AMPs has been rigorously pursued. In this review, we focus on the current knowledge of α-helical cationic antimicrobial peptides, one of the most common types of AMPs in nature.

Reflection on Integrating the Humanistic Quality Education into Clinical Nursing Teaching / 中华医学教育探索杂志

To enhance the quality education of nursing students and cultivate high quality nursing staff,who can meet the social requirements,a new mode of integrating humanistic quality education into clinical nursing education is proposed.Approaches to improve humanistic quality of nursing students are initiated from four aspects: determination of teaching goals,establishment of teaching tenet "human as basis",optimization of learning environment and vividness of teaching methods.The main purpose of this paper is to promote research and practice for further innovation in Chinese nursing clinical teaching.