Transcription analysis of the genes tcdA-E of the pathogenicity locus of Clostridium difficile.
To analyse the transcription pattern of the five tcdA-E genes of the pathogenicity locus (PaLoc) of Clostridium difficile a protocol was established to purify RNA from strain VPI10463. Transcription analysis of the five tcdA-E genes showed that they were all transcribed. In the early exponential phase, a high level of tcdC and low levels of tcdA,B,D,E transcripts were detectable; this was inverted in the stationary phase, suggesting that TcdC might have a negative influence on transcription of the other genes. Three transcription initiation sites, one for tcdA and two for tcdB were determined by primer extension analysis. Readthrough transcripts from outside the locus were not obtainable, s…
MGMT in primary and recurrent human glioblastomas after radiation and chemotherapy and comparison with p53 status and clinical outcome
The DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) plays a pivotal role in alkylating drug resistance. Here, we determined MGMT activity in primary and recurrent glioblastomas (GBM, WHO grade IV) of patients who received radiation therapy (RT) or RT plus chemotherapy with alkylating agents (temozolomide, chloroethylnitrosoureas). The mean MGMT activity of untreated GBM was 37 +/- 45 (range 0-205) fmol/mg proteins. In the 1st, 2nd and 3rd recurrences, MGMT activity increased from 66 +/- 50 (13-194) to 68 +/- 44 (14-143) and 182 +/- 163 (64-423) fmol/mg protein, respectively. Comparing patients who received RT only with RT plus chemotherapy, a significant increase of MGMT …
External validation of a prognostic model estimating the survival of patients with recurrent high-grade gliomas after reirradiation
PURPOSE: We aimed to validate a controversial prognostic model for the survival of relapsed malignant glioma patients after reirradiation with an independent, multicentric patient cohort.METHODS AND MATERIALS: A total of 165 malignant glioma patients underwent reirradiation at 4 different institutions between 1994 and 2012. Twenty-two patients had a good (score 1), 44 had a moderate (score 2), and 99 had a poor prognosis (score 3 or 4). Four statistical methods were used to validate the prognostic model: First, we compared survival according to prognostic group in the construction and the validation cohort by visual comparison of the respective Kaplan-Meier plots. Second, discrimination was…
Symmetrical Infarction of the Cervical Spinal Cord Due to Spontaneous Bilateral Vertebral Artery Dissection
To the Editor: Vertebral artery (VA) dissection is a well-known cause of vertebrobasilar ischemia in young people and may be due to preceding chiropractic maneuvers, cystic medial necrosis, mucopolysaccharidosis and reticular fiber diseases, vasculitis,1 2 or a yet-unknown arteriopathy.3 Common findings in VA dissection are unilateral or bilateral neck pain associated with cerebellar and brain stem (usually medullary) infarctions,2 3 which are rarely associated with clinical signs of spinal cord lesions.4 5 6 Recently, 1 patient each was described with bilateral spinal cord infarction7 and Brown-Sequard’s syndrome8 as the sole manifestation of spontaneous unilateral VA dissection. We add an…
Definition of the single integration site of the pathogenicity locus in Clostridium difficile.
We determined the nucleotide sequence 3.8 kb upstream and 5.2 kb downstream of the toxin genes A and B of Clostridium difficile. Nine ORFs were discovered. Based on PCR-directed approaches, two were attributed to the pathogenicity locus (PaLoc). The other seven were found in every C. difficile isolate obtained from the human gastrointestinal tract, respectless of their toxinogenicity. The ORFs cdu1 and cdu2/2' upstream of the PaLoc displayed similarity to repressors of Gram-positive bacteria (cdu1), and to an Na+/H+ antiporter described for Enterococcus hirae (cdu2/2'). Downstream of the locus a putative ABC transporter (cdd2-4) was identified. With a set of three paired primers used in pol…
Randomized phase III study of whole-brain radiotherapy for primary CNS lymphoma
Objective: This is the final report of a phase III randomized study to evaluate whole-brain radiotherapy (WBRT) in primary therapy of primary CNS lymphoma (PCNSL) after a median follow-up of 81.2 months. Methods: Patients with newly diagnosed PCNSL were randomized to high-dose methotrexate (HDMTX)–based chemotherapy alone or followed by WBRT. We hypothesized that the omission of WBRT would not compromise overall survival (OS; primary endpoint), using a noninferiority design with a margin of 0.9. Results: In the per-protocol population (n = 320), WBRT nonsignificantly prolonged progression-free survival (PFS) (median 18.2 vs 11.9 months, hazard ratio [HR] 0.83 [95% confidence interval (CI) 0…