Influence of the magnetic field on microorganisms in the oral cavity

Since the beginning of their lives, all living organisms are exposed to the influence of geomagnetic fields.

Objectives

: With respect to the positive effects that magnetic fields have on human tissues, especially the bactericidal effect, this investigation aimed to assess their influence on the reduction of oral microorganisms.

Material and Methods

: In order to obtain adequate specimens of dental plaque deposit, microbes such as Streptococcus parasanguinis, Staphylococcus epidermidis, Rhodococcus equi and Candida albicans were isolated from the human mouth. To establish the intensity of microbial growth on the basis of the modified optical density (OD) of agar turbidimetry assay, microbial count and spectrophotometry were applied. The study was carried out with two microbial concentrations (1 and 10 CFU/ml) after periods of incubation of 24 and 48 h and using micromagnets.

Results

: A positive effect of the magnetic field, resulting in the reduction of dental plaque microbes in vitro, was found. In the first 24 hours of exposure to the magnetic field, the number of all isolated microbes was significantly reduced. The most potent influence of magnets and the most intensified reduction after 24 hours were evident in Candida albicans colonies. The decrease in the influence of magnets on microbes in vitro was also detected.

Conclusions

: Magnets reduce the number of microbes and might be recommended as a supplement in therapy for reduced periodontal tissues. This is important because periodontal tissues that are in good conditions provide prolonged support to the oral tissues under partial and supradental denture.     

Evaluation of the anti-candidal activity of methanolic leaf extract of cleistopholis patens (fam. Annonaceae) on candida species isolated from stage II HIV patients

BackgroundCandida species (sp) is implicated in causing opportunistic disseminated mycotic complications in stage II HIV patients. Cleistopholis patens is a West African medicinal tree reported to have significant antifungal activity against C. albicans.ObjectivesThis study aimed to determine the anti-candidal activity of methanolic leaf extract of Cleistopholis patens against Candida species isolated from stage II HIV patients.MethodsThe minimum inhibitory concentration (MIC) of the extract and Nystatin®® was determined by agar dilution method. The killing rate studies of the plant extract and Nystatin® were also determined.ResultsThe extract had activity against all Candida isolates, with the MIC against the five isolates ranging from 6.0 – 9.8 mg/ml. Nystatin® also demonstrated plausible activity against the isolates with MICs ranging from 0.3125 — 25 mg/ml. Candida albicans strain 2 was the most sensitive to both extract and Nystatin® with MIC values of 6 and 0.3125 mg/ml respectively. Candida krusei was the least sensitive with MIC values of 9.8 and 25 mg/ml for the extract and Nystatin® respectively. The killing rate values for the extract ranged from −0.029 to −0.091 min⁻¹ and that of Nystatin® ranged from −0.076 to −0.112¹⁶ min⁻¹.ConclusionsThe results indicate that the methanolic extract of Cleistopholis patens is a promising clinical alternative besides Nystatin® in the treatment of infections caused by Candida species in stage II HIV patients.     

Facial Candidal Abscess in a Patient with Unknown Type 2 Diabetes Mellitus

Introduction

Facial candidal abscess is an infection with a fungal cause which was presented in this case such a rarity. We report a rare case of facial abscess due to Candida species in a patient with unknown diabetes.

Materials and Methods

The patient presented with a longstanding firm swelling which occurred 2 weeks ago and did not show any improvement of healing process in spite of surgical and medical treatments. MRI examinations were conclusive and compatible with abscess, so she underwent surgical intervention. Facial candidal abscess was the final diagnosis.

Conclusions

We concluded that, in persistent abscesses, invasive candidiasis should be considered in the differential diagnosis of bacterial infections as it generally affects individuals with diabetes or general defects in the immune system, or those who use widespread antibiotics and steroids.     

黄连解毒汤对白色念珠菌的抗真菌作用研究

目的 观察黄连解毒汤对白色念珠菌的体外抗真菌效果.方法 采用微量稀释法药物敏感性试验测定黄连解毒汤对标准菌株、氟康唑敏感株、氟康唑中度敏感株、氟康唑耐药株4种白色念珠菌的最低抑菌浓度.结果 黄连解毒汤对4种白色念珠菌均具有较好的抑制作用,其对白色念珠菌标准菌株的最低抑菌浓度为4mg/ml,对氟康唑敏感型白色念珠菌最低抑菌浓度为8mg/ml,对中度敏感型白色念珠菌最低抑菌浓度为16mg/ml,对耐药型白色念珠菌最低抑菌浓度为 64mg/ml.结论 黄连解毒汤对白色念珠菌有明显的抑制作用,可作为临床用药的参考.     

系统性念珠菌感染小鼠模型的制备

目的 建立稳定的系统性念珠菌感染小鼠模型,规范其操作方法。方法 采用环磷酰胺对小鼠进行免疫抑制后,选择白色念珠菌（C.albicans）和非白念珠菌（C.parapsilosis）分别接种ICR小鼠,从免疫抑制、菌株制备、接种剂量和接种途径等方面对建模过程进行质量控制,通过生存分析、组织载菌量和病理学检查对模型进行评价。结果 我们建立的系统性念珠菌感染小鼠模型显示肾脏为靶器官,多器官弥散性真菌感染的典型病理组织学改变。结论 通过对建模过程各环节进行规范,可得到稳定的系统性念珠菌感染小鼠模型,该模型可应用于系统性念珠菌感染的致病机理,免疫防御及抗真菌药物筛选等研究领域。     

黄根醇提物体外抗白念珠菌生物膜作用的研究

目的观察黄根醇提取物体外对白色念珠菌生物膜及相关基因的影响。方法 M27-A2测定黄根醇提取物对白色念珠菌的最小抑菌浓度(MIC);XTT法评价黄根醇提取物对白色念珠菌生物膜形成的影响;实时荧光定量RT-PCR(q RT-PCR)检测黄根醇提取物作用后,ALS基因的表达情况。结果黄根醇提取物对白色念珠菌的MIC为8μg/m L;随着浓度的增加,黄根醇提取物对白色念珠菌生物膜的抑制作用增强,呈正相关性;16μg/m L黄根醇提取物对不同生长阶段的白色念珠菌生物膜均有抑制作用,抑制率随生物膜成熟逐渐降低;q RT-PCR结果显示,药物作用后ALS2、ALS3基因表达降低(7.87±0.27比5.15±0.34;6.24±0.51比2.13±0.23,P<0.05),ALS1基因表达无明显变化(6.11±0.14比5.95±0.31,P>0.05)。结论黄根醇提取物对体外白色念珠菌生物膜有较明显的抑制作用,可能通过抑制ALS2、ALS3基因的表达而实现。     

Differential role of NK cells against Candida albicans infection in immunocompetent or immunocompromised mice

Little is known regarding the role of NK cells during primary and secondary disseminated Candida albicans infection. We assessed the role of NK cells for host defense against candidiasis in immunocompetent, as well as immunodeficient, hosts. Surprisingly, depletion of NK cells in immunocompetent WT mice did not increase susceptibility to systemic candidiasis, suggesting that NK cells are redundant for antifungal defense in otherwise immunocompetent hosts. NK‐cell‐depleted mice were found to be protected as a consequence of attenuation of systemic inflammation. In contrast, the absence of NK cells in T/B/NK‐cell‐deficient NSG (NOD SCID gamma) mice led to an increased susceptibility to both primary and secondary systemic C. albicans infections compared with T/B‐cell‐deficient SCID mice. In conclusion, this study demonstrates that NK cells are an essential and nonredundant component of anti‐C. albicans host defense in immunosuppressed hosts with defective T/B‐lymphocyte immunity, while contributing to hyperinflammation in immunocompetent hosts. The discovery of the importance of NK cells in hosts with severe defects of adaptive immunity might have important consequences for the design of adjunctive immunotherapeutic approaches in systemic C. albicans infections targeting NK‐cell function.