Is the oral fungal pathogen Candida albicans a cariogen?

Pathobiology of dental caries is complex. Data from recent molecular microbiologic studies have further redefined the role of the oral microbiome in the etiology of dental caries. This new information challenges the conventional view on the hegemony of classic cariogenic prokaryotes such as Streptococcus mutans in caries etiology, and raises the intriguing possibility of the participation of the eukaryotic oral fungal pathogen Candida in the caries process. The virulence attributes of Candida species such as their acidogenicity and aciduric nature, the ability to develop profuse biofilms, ferment and assimilate dietary sugars, and produce collagenolytic proteinases are all indicative of their latent cariogenic potential. Based on the above, oral candidal counts have been used by some as a caries risk indicator. On the contrary, other studies suggest that Candida is merely a passenger extant in an acidic cariogenic milieu, and not a true pathogen. In this review, we critically examine the varying roles of Candida, and traditionally accepted cariogens such as the mutans group of streptococci in the pathobiology of dental caries. The weight of available data tends to imply that Candida may play a pivotal role as a secondary agent perpetuating the carious process, especially in dentinal caries.     

自身免疫性肝炎患者自身抗体的测定及意义

目的:探讨自身抗体测定对诊断自身免疫性肝炎的临床意义．方法:采用间接免疫荧光法(IIF)检测47例自身免疫性肝炎患者、158例非自身免疫性肝炎患者及40例健康体检者体内抗核抗体(ANA)、抗平滑肌抗体(SMA)、抗中性粒细胞胞质抗体(ANCA)、抗线粒体抗体(AMA)等自身抗体,ELISA法检测抗MPO抗体,并对结果进行回顾性分析．结果:ANA、SMA及ANCA检出率的比较,结果显示AIH中阳性率最高为SMA(66．0％, 31／47),而非AIH中则为6．3％(10／158),两组差异有非常显著性意义(P<0．01)．经X2检验, SMA、AMA和MPO抗体检测在AIH与PBC中,均有非常显著性意义(P<0．01)．AIH各型自身抗体检测结果表明,AIH-Ⅰ与ANA、SMA和ANCA相关,AIH-Ⅱ与LKM相关,而AIH=Ⅲ与SLA和ANCA相关．结论:血清自身抗体的检测对诊断、治疗和阻止自身免疫性肝炎的发展有着十分重要作用,对提高AIH在临床上同其他肝病鉴别诊断和治疗有着非常重要的意义．     

Mutations in N-ras predominate in acute myeloid leukemia

Using synthetic oligomers we investigated fresh samples of acute myeloid leukemia (AML) for the presence of mutated ras oncogenes. Our original results showed that five of eight samples contained a mutation in codon 13 of the N-ras gene. In a subsequent study involving 37 samples, we found only one N-ras-13 mutation, and, in addition, mutations in codon 61 of the N-ras gene in four cases and a mutation in codon 12 of the Ki-ras gene in two cases. Amplification of ras genes was not observed. We conclude that in approximately 20% to 25% of AML cases, a mutated ras oncogene is present, predominantly the N-ras gene. The occurrence of mutations does not correlate with the cytological features of the leukemia.     

Outcomes of dental implants placed in a surgical training programme

Background: This study evaluates surgical outcomes and survival rates of implants placed in a multidisciplinary implant teaching programme. Methods: A retrospective review of all implant surgery performed over a 6‐year period by accredited oral and maxillofacial surgery trainees at the Royal Dental Hospital of Melbourne was undertaken. Patients were reviewed for a minimum of 6 months post‐implant placement. Implant survival was defined as those implants which were not removed, were clinically integrated as assessed by torque testing and in an appropriate position to receive a subsequent prosthesis. Kaplan‐Meier analysis was used to assess overall survival and univariate factors affecting survival. Multivariate analysis used Cox proportional hazards models. Results: Over 6 years, 127 patients were treated. Follow‐up data were present for 105 patients with 236 implants placed. Survival of implants at 1 and 5 years was 94 per cent and 92.8 per cent, respectively. The only univariate and multivariate factor which affected implant survival was perioperative bone grafting. All failed implants were single stage. Other factors such as patient age, smoking status, implant site, anaesthetic type, immediate or delayed placement, implant length and diameter, and medical comorbidities did not significantly affect implant survival. Conclusions: A satisfactory implant survival rate was found in a tertiary teaching centre. Perioperative bone grafting significantly increased the risk of implant failure.