Genome-wide screening of DNA copy number alterations in cervical carcinoma patients with CGH+SNP microarrays and HPV-FISH

Alterations in the genome that lead to changes in DNA sequence copy number are characteristic features of solid tumors. We used CGH+SNP microarray and HPV-FISH techniques for detailed screening of copy number alterations (CNAs) in a cohort of 26 patients with cervical carcinoma (CC). This approach identified CNAs in 96.2% (25/26) of tumors. Array-CGH discovered CNAs in 73.1% (19/26) of samples, HPV-FISH experiments revealed CNAs in additional 23.1% (6/26) of samples. Common gains of genetic sequences were observed in 3q (50.0%), 1q (42.4%), 19q (23.1%), while losses were frequently found in 11q (30.8%), 4q (23.1%) and 13q (19.2%). Chromosomal regions involved in loss of heterozygosity were observed in 15.4% of samples in 8q21, 11q23, 14q21 and 18q12.2. Incidence of gain 3q was associated with HPV 16 and HPV 18 positive samples and simultaneous presence of gain 1q (P = 0.033). We did not found a correlation between incidence of CNAs identified by array-CGH and HPV strain infection and incidence of lymph node metastases. Subsequently, HPV-FISH was used for validation of array-CGH results in 23 patients for incidence of hTERC (3q26) and MYC (8q24) amplification. Using HPV-FISH, we found chromosomal lesions of hTERC in 87.0% and MYC in 65.2% of specimens. Our findings confirmed the important role of HPV infection and specific genomic alterations in the development of invasive cervical cancer. This study also indicates that CGH+SNP microarrays allow detecting genome-wide CNAs and copy-neutral loss of heterozygosity more precisely, however, it may be less sensitive than FISH in samples with low level clonal CNAs.     

Oral N-acetylcysteine has a deleterious effect in acute iron intoxication in rats

Acute iron intoxication is associated with depletion of reduced glutathione in hepatocytes and changes in the glutathione system enzymes. We hypothesized that treatment with N-acetylcysteine (NAC), a glutathione reducing agent and an antioxidant, would reduce mortality in acute iron intoxication. We used a rat model to test this hypothesis. Male rats were assigned to 4 groups. Group 1 received 400 mg/kg elemental iron by oral gavage, group 2 received the same dose of iron followed by NAC, group 3 received NAC only, whereas group 4 received distilled water. Iron and liver transaminases in the blood, and glutathione system enzymes in the liver and erythrocytes were measured. Mortality in group 2 was significantly higher after 2, 6, and 24 hours compared with group 1 (P < .001). No deaths were observed in groups 3 and 4. Serum iron levels were significantly higher in group 2 rats compared to group 1 rats (P < .001). Hepatic and erythrocyte glutathione system enzymes were significantly lower among rats in group 2 compared to rats in group 1. The administration of NAC probably increased the absorption of iron through the gastrointestinal tract, causing higher serum iron levels with significant hepatic damage. These results indicate that in a rat model of acute iron intoxication, orally administered NAC may increase mortality.     

Balancing high accrual and ethical recruitment in paediatric oncology: a qualitative study of the 'look and feel' of clinical trial discussions

Background  

High accrual to clinical trials enables new treatment strategies to be tested rapidly, accurately and with generalisability. Ethical standards also must be high so that participation is voluntary and informed. However, this can be difficult to achieve in trials with complex designs and in those which are closely embedded in clinical practice. Optimal recruitment requires a balance of both ethical and accrual considerations. In the context of a trial of stratified treatments for children with acute lymphoblastic leukaemia (UKALL2003) we examined how recruitment looked to an observer and how it felt to the parents, to identify how doctors' communication could promote or inhibit optimal recruitment.     

Identification of insect-selective and mammal-selective toxins from Parabuthus leiosoma venom.

Venoms were collected from two scorpion species: Parabuthus leiosoma and Parabuthus pallidus from Kenya. Subcutaneous injection and oral toxicity tests of crude and pure fractions of scorpion venoms were done in Mus musculus (mice), Chilo partellus and Busseola fusca. The highest activity against C. partellus was found in P. leiosoma venom (LC(50) 0.689 mg/50mg body weight). Bioassay-guided purification by a combination of cation-exchange (CE) and reverse-phase high-performance liquid chromatography (RP-HPLC) led to the isolation of three toxic peptides. A lepidopteran-selective toxin (P. leiosoma insect toxin, Plit) was isolated, and the partial N-terminal amino acid sequence (-KDGYPVDNANCKYE-) plus the molecular weight (6688.5 Da) determined. A peptide with significant insect toxicity coupled with mild effects on mice (P. leiosoma toxin, Plt) was isolated, and the partial N-terminal amino acid sequence (-LCEKFKVQRLVELNCVD-) plus the molecular weight (6742.5 Da) was determined. Another toxin with anti-mammalian activity (P. leisoma mammal-selective toxin, Plmt), and N-terminal partial amino acid sequence of ADVPGNYPLDKNGNRYY- plus a molecular weight of 7145.5 Da was also isolated. Comparison of the partial N-terminal amino acid sequences with other toxins revealed that Plit shows high homology to other known insect toxins. Similarly, Plmt shows high homology with several birtoxin-like anti-mammalian toxins. Plt does not exhibit homology with any known scorpion toxin with combined anti-insect and anti-mammalian activity.     

Comparative analysis of p53 gene mutations and protein accumulation in human non-small-cell lung cancer

A series of 54 resected primary non-small-cell lung carcinomas was analyzed for p53 gene mutations and for p53 protein accumulation and the findings were correlated with clinical parameters. Mutations in exons 5 through 8 of the p53 gene were identified by a denaturing gradient gel electrophoresis (DGGE) assay and cycle sequencing, whereas p53 protein accumulation was detected in paraffin-embedded tissue by immunostaining using 2 different murine monoclonal antibodies (MAbs) (BP53-12 and DO7). A p53 gene mutation and/or p53 protein accumulation was found in 37 of 54 tumors. Mis-sense mutations were closely associated with positive immunostaining, which was intense in 15 out of 17 cases with a mutation. In 10 tumors, obvious p53 accumulation was detected in the absence of mutations in exons 5 through 8. Conversely, only one of 8 p53 non-sense mutations led to detectable p53 accumulation. The most frequent single base changes were G → T transversions and C → T transitions. The presence of a p53 alteration was not related to age, tumor size, stage or histology. However, we found a significant inverse correlation between p53 alterations and the presence of a K-ras mutation. This was reflected in the overall postoperative survival data: patients with p53 alterations in their tumors tended to have a better prognosis than those without a p53 alteration; however, this difference was lost when cases with a K-ras mutation were omitted from the analysis. © 1995 Wiley-Liss, Inc.