Bisphosphonates are not associated with vertebral osteonecrosis

Intravertebral clefts are considered markers for osteonecrosis. We tested the hypothesis that bisphosphonate therapy was associated with vertebral osteonecrosis. A retrospective review of a vertebroplasty database was performed. Exposure to, duration of, and type of bisphosphonate therapy was documented. Radiographs were reviewed to identify intravertebral gas-filled or fluid-filled clefts, which are considered a marker for vertebral osteonecrosis. Proportion of patients with and without clefts was compared between the group exposed to bisphosphonates and the unexposed group using Chi-squared test. Duration of bisphosphonate exposure was compared between patients with and without clefts using Student's t-test. After exclusion of 16 patients with malignancy and 21 with chronic steroid therapy 237 patients were identified. Sixty-seven (28%) of the total cohort of patients were prescribed bisphosphonate therapy. Overall, clefts were present in 68 (29%) of the 237 patients. Among the 67 patients exposed to bisphosphonate therapy, 15 patients (22%) had clefts. Among the 170 patients not exposed to bisphosphonate therapy, 53 patients (31%) had clefts (P = 0.17 compared to bisphosphonate therapy group). Mean duration of bisphosphonate therapy among patients with clefts was 52 ± 63 weeks and among patients without clefts was 57 ± 79 weeks (P = 0.80). Intravertebral clefts are not associated with bisphosphonate therapy. If these clefts indicate osteonecrosis, then bisphosphonate therapy does not appear to be associated with vertebral osteonecrosis.     

Conjugative transfer of chromosomally encoded antibiotic resistance from Helicobacter pylori to Campylobacter jejuni

Many strains of Helicobacter pylori are naturally competent for transformation and able to transfer chromosomal DNA among different isolates using a conjugation-like mechanism. In this study, we sought to determine whether H. pylori can transfer DNA into Campylobacter jejuni, a closely related species of the Campylobacterales group. To monitor the transfer, a chromosomally encoded streptomycin resistance cassette prearranged by a specific mutation in the rpsL gene of H. pylori was used. Mating of the bacteria on plates or in liquid broth medium produced C. jejuni progeny containing the streptomycin marker. DNA transfer was unidirectional, from H. pylori to C. jejuni, and the progeny were genetically identical to C. jejuni recipient strains. DNase I treatment reduced but did not eliminate transfer, and DNase I-treated cell supernatants did not transform, ruling out phage transduction. Recombinants also did not occur when the mating bacteria were separated by a membrane, suggesting that DNA transfer requires cell-to-cell contact. Transfer of the streptomycin marker was independent of the H. pylori comB transformation system, the cag pathogenicity island, and another type IV secretion system called tfs3. These findings indicated that a DNase I-resistant, conjugation-like mechanism may contribute to horizontal DNA transfer between different members of the Campylobacteriales group. The significance of this DNA uptake by C. jejuni in the context of acquiring antibiotic resistance is discussed.     

Predicting the molecular role of MEIS1 in esophageal squamous cell carcinoma

Tumor Biology - The three amino acid loop extension (TALE) class myeloid ecotropic viral integration site 1 (MEIS1) homeobox gene is known to play a crucial role in normal and tumor development. In...     

使用Pentacam检测亚临床期和早期圆锥角膜患者角膜体积和前房容积

目的:使用Pentacam检测健康、亚临床期和早期圆锥角膜患者角膜体积和前房容积。方法:流行病学研究。共纳入63例屈光手术患者。根据Amsler-Krumeich标准,将患者分为正常、亚临床期和早期三组。收集了包括年龄和性别在内的人口统计信息,并获得了患者的完整病史。所有患者进行完整的视力检查。随后,使用Pentacam测量三组患者的角膜体积和前房容积。结果:对照组角膜体积明显高于亚临床期组和早期组(P<0.05),但两组间前房容积无显著性差异(P>0.05)。结论:测量角膜体积有助于鉴别亚临床期圆锥角膜和早期圆锥角膜与正常眼。亚临床圆锥角膜患者、早期圆锥角膜患者和正常人的前房容积无显著差异。