Botulinum toxin blocks mast cells and prevents rosacea like inflammation

Background

Rosacea is a chronic inflammatory skin condition whose etiology has been linked to mast cells and the antimicrobial peptide cathelicidin LL-37. Individuals with refractory disease have demonstrated clinical benefit with periodic injections of onabotulinum toxin, but the mechanism of action is unknown.

Neutrophilic defensins penetrate the blood-brain barrier

Defensins are small, cationic, cyclic peptides that are abundantly stored in granules of neutrophils. Defensins non-specifically interact with membranes by forming weakly ion-selective pores. Here we demonstrate immunolocalization of defensin-secreting cells in human brain. Defensins, secreted by activated granulocytes, apparently are not prevented by the blood-brain barrier (BBB) from diffusing across cerebral endothelium to penetrate the neuropil for a considerable distance from the granulocyte. This is in contrast to other neutrophil proteins like the granuleassociated enzyme elastase or the cytosolic protein MRP-14, which are strictly localized to the cytoplasm or granules of neutrophils. Thus, defensins, known chemokinetic and chemotactic molecules, display a unique distribution at BBB sites. © 1995 Wiley-Liss, Inc.     

Clinical and immunological effects of azithromycin in Behçet''s disease

Background: The aim of this study was to evaluate the effects of azithromycin on mucocutaneous manifestations, oral health and immune response in Behçet's disease (BD). Methods: Eight BD patients with active mucocutaneous symptoms were treated with azithromycin for 4 weeks. Oral health, clinical manifestations and in vitro interleukin (IL)‐12, interferon (IFN)‐γ, IL‐10 and monocyte chemotactic protein (MCP)‐1 responses were evaluated before and after treatment. Results: The number of folliculitic lesions, healing time of oral ulcers and scores of plaque indexes (PLIs) were lower after azithromycin treatment (P < 0.05). Scores of PLIs correlated positively with the healing time of oral ulcers (P = 0.02). Although a trend towards increased stimulated IL‐10 responses with azithromycin was observed, no statistically significant difference was found. Stimulated and unstimulated MCP‐1, IFN‐γ and IL‐12 responses were similar before and after treatment (P > 0.05). Conclusion: Azithromycin was observed to be effective in decreasing folliculitic lesions and fastening the healing time of oral ulcers in BD.     

Antimicrobial susceptibility of respiratory Haemophilus influenzae strains isolated from pediatric respiratory tract infections

BACKGROUND: Haemophilus influenzae (H. influenzae) is the most frequent bacterial pathogen of respiratory tract infections in children. Detection of antimicrobial susceptibility of H. influenzae is necessary for institution of appropriate antibiotic treatments. METHODS: A total of 281 strains of H. influenzae isolated from sputum samples of 281 pediatric patients with respiratory tract infections were recruited for study. Antibiotic susceptibility was determined by assessing minimum inhibitory concentrations (MIC) of antimicrobial agents. MIC were measured by utility of Agar dilution susceptibility test. RESULTS: Of the total, 38 (13.5%) strains produced beta-lactamase (BLP), 56 (19.9%) strains were beta-lactamase non-producing, ampicillin resistant (BLNAR). The overall resistant proportion to ampicillin was 33.4%. The data indicated that sulbactam/ampicillin, cefotaxime, ceftriaxone and cefditoren are effective against BLP strains. In addition, a high prevalence of BLNAR H. influenzae strains was identified, with an overall isolation rate of 19.9%. Those strains mainly demonstrated intermediate level to ampicillin (ampicillin-MIC antimicrobial activities of cefotaxime, ceftriaxone and cefditoren against those strains were slightly diminished. Recovery rate of BLP strains was varied by years, peaking at 19.5%. In particular, a trend of yearly increase in frequency of BLNAR strains was observed. CONCLUSION: Frequency of BLNAR strains causing respiratory infections has been dramatically increasing, which can diminish antibiotic activities of not only ampicillin but also of some cephems.     

医院感染常见细菌分布与耐药性分析

目的了解细菌分布及常见细菌的耐药性。方法回顾性分析某院2000—2004年临床标本分离的细菌及其耐药性监测结果。结果1439株细菌中，革兰阳性菌456株（31．69％），以凝固酶阴性表皮葡萄球菌为多，达206株（45．18％），其次为金黄色葡萄球菌92株（20．18％）；两种葡萄球菌的耐药率相似，对万古霉素耐药率均为0。革兰阴性菌983株，前5位依次为肠杆菌属346株（35．20％），克雷伯菌属164株（16，68％），铜绿假单胞菌155株（15．77％），埃希菌属101株（10．27％），变形杆菌属94株（9．56％）；前5位革兰阴性菌对常用抗菌药物的耐药性以半合成青霉索较明显，铜绿假单胞菌的耐药性较突出。结论应高度重视细菌变迁和耐药性监测，提高抗菌药物合理应用水平。     

Influence of preformed α-helix and α-helix induction on the activity of cationic antimicrobial peptides

One prominent class of cationic antibacterial peptides comprises the α-helical class, which is unstructured in free solution but folds into an amphipathic α-helix upon insertion into the membranes of target cells. To investigate the importance of α-helicity and its induction on interaction with membranes, a series of peptides was constructed based on a hybrid of moth cecropin (amino acids 1-8) and bee melittin (amino acids 1-18) peptides. The new peptides were predicted to have a high tendency to form α-helices or to have preformed α-helices by virtue of construction of a lactam bridge between glutamate and lysine side-chains at positions i and i+ 4 at various locations along the primary sequence. In two examples where the use of lactam bridge constraints induced and stabilized α-helical structure in benign (aqueous buffer) and/or hydrophobic medium, there was a decrease in antibacterial activity relative to the linear counterparts. Thus the preformation of α-helix in solution was not necessarily beneficial to antimicrobial activity. In the one case where the lactam bridge did result in increased antibacterial activity (lower minimal inhibitory concentration values) it did not increase α-helical content in benign or hydrophobic medium. Broadly speaking, good activity of the peptides against Pseudomonas aeruginosa correlated best (r²= 0.88) with a helican parameter which was calculated as the induction of α-helix in α membrane-mimicking environment divided by the α-helix formation under benign conditions. Interestingly, the activity of the lactam bridge peptide constructs correlated in part with alterations in bacterial outer or cytoplasmic membrane permeability.     

The use of locally-delivered chlorhexidine in the treatment of periodontitis. Clinical results*

Abstract. Since the advent of a nondegradable controlled local delivery of antibiotics in 1979, several second generation systems have been developed. Second generation systems have attempted to improve on the early system. Chlorhexidine has been used effectively for over 30 years as an antiseptic. In the early 1970s, chlorhexidine gluconate was incorporated at 0.2% into mouthrinses in Europe and in 1986 it was incorporated at 0.12%, in a mouthrinse in the United States. Since these mouthrinses were effective in reducing the supragingival flora, had a high safety margin, and had no reported bacterial resistance, chlorhexidine offered a therapeutic advantage for a local delivery system. This system was developed and studied. This report will discuss this new biodegradable system containing chlorhexidine gluconate as the active agent (PerioChip^®). Parmacokinetics of the system and a review of the multicenter studies in Europe and the United States are discussed. In these randomized clinical trials the chlorhexidine chip has been shown to enhance the effects of scaling and root planing. Chlorhexidine chip in conjunction with scaling and root planing, when compared to scaling and root planing alone, has shown significant improvement in probing pocket depth reduction, probing attachment level and bleeding on probing. This delivery system, in combination with scaling and root planing, has also resulted in significantly more probing depth reductions of 2 mm or more. The system is safe and efficacious. Placement of the chip is usually done in less than 1 min, it requires no retention system, biodegrades, and does not require a follow-up dental appointment.     

Antimicrobial effect of radiation of ionized plasma

Department of Experimental Surgery, Interfaculty Laboratory Complex, and Department of Clinical Laboratory Diagnosis, Postgraduate Medical Faculty, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Kupriyanov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 10, pp. 413–145, October, 1990.