High mobility group proteins 1 and 2 recognize chromium-damaged DNA

Chromium (Cr) is a human carcinogen and a potent DNA damaging agent. Incubation of DNA with CrCl3 resulted in dose-dependent binding of Cr to DNA and, at concentrations >20 microM, altered the electrophoretic mobility of a 100 bp oligonucleotide. We also demonstrate that high mobility group (HMG) proteins 1 and 2 bind Cr-damaged DNA (Cr-DNA). Protein binding was lesion density-dependent, with maximal binding to DNA treated with 100 microM CrCl3. HMG2 binds to Cr-DNA with a calculated Kd of approximately 10(-9) M. These proteins also bound DNA obtained from chromate-treated cells. These results suggest that the covalent attachment of Cr to DNA induces alterations in DNA structure which are recognized by HMG1 and HMG2. Therefore, these proteins may function as Cr-damaged DNA recognition proteins in vivo and as a consequence of binding, may play a role in directing the cellular response to Cr-DNA adduct formation.      

Sexual precocity: sex incidence and aetiology

The aetiology of 197 girls and 16 boys presenting with sexual precocity was reviewed. Ninety one girls and four boys had central precocious puberty (M:F 23:1); a cause was identified in all the boys but in only six girls. All boys with precocious puberty need detailed investigation; in girls investigation should be based on clinical findings, particularly the consonance of puberty.     

Interrater reliability: completing the methods description in medical records review studies

In medical records review studies, information on the interrater reliability (IRR) of the data is seldom reported. This study assesses the IRR of data collected for a complex medical records review study. Elements selected for determining IRR included "demographic" data that require copying explicit information (e.g., gender, birth date), "free-text" data that require identifying and copying (e.g., chief complaints and diagnoses), and data that require abstractor judgment in determining what to record (e.g., whether heart disease was considered). Rates of agreement were assessed by the greatest number of answers (one to all n) that were the same. The IRR scores improved over time. At 1 month, the reliability for demographic data elements was very good, for free-text data elements was good, but for data elements requiring abstractor judgment was unacceptable (only 3.4 of six answers agreed, on average). All assessments after 6 months showed very good to excellent IRR. This study demonstrates that IRR can be evaluated and summarized, providing important information to the study investigators and to the consumer for assessing the reliability of the data and therefore the validity of the study results and conclusions. IRR information should be required for all large medical records studies.     

Incidence of a clinical diagnosis of the irritable bowel syndrome in a United States population

BACKGROUND: The incidence of irritable bowel syndrome is uncertain. We aimed to determine the incidence of clinically diagnosed irritable bowel syndrome in the community. METHODS: Using the Rochester Epidemiology Project, all diagnoses of irritable bowel syndrome made among adult residents of Olmsted County, Minnesota, over a 3-year period were identified. The complete medical records of a random sample of the potential subjects were reviewed for the 10 years prior to the irritable bowel syndrome diagnosis and any patient who had received a previous diagnosis of irritable bowel syndrome was excluded (prevalent cases). RESULTS: The diagnostic index listed 1245 possible irritable bowel syndrome patients; 416 patient charts were reviewed and, of these, 149 were physician diagnosed incident cases of irritable bowel syndrome. The age- and sex-adjusted incidence rate was 196 per 100,000 person-years and increased with age (P = 0.006). The age-adjusted annual incidence per 100,000 in women was higher than in men: 238 vs. 141 (ratio 3:2; P = 0.005). The overall symptom frequency at the time of diagnosis was abdominal pain (73%), diarrhoea (41%) and constipation (16%). CONCLUSIONS: The incidence of a clinical diagnosis of irritable bowel syndrome in adults was estimated to be two per 1000 per year, increased with age and was higher in women than men. As many people with irritable bowel syndrome do not seek care, the true incidence of irritable bowel syndrome is likely to be higher.     

Validation and reproducibility of computerised cell-viability analysis of tissue slices

Background

The identification of live cells using membrane integrity dyes has become a frequently used technique, especially with articular cartilage and chondrocytes in situ where tissue slices are used to assess cell recovery as a function of location. The development of a reproducible computerised method of cell evaluation would eliminate many variables associated with manual counting and significantly reduce the amount of time required to evaluate experimental results.

Methods

To validate a custom computerised counting program, intra-person and inter-person cell counts of nine human evaluators (three groups – unskilled, novice, and experienced) were compared with repeated pixel counts of the custom program on 15 digitised images (in triplicate) of chondrocytes in situ stained with fluorescent dyes.

Results

Results indicated increased reproducibility with increased experience within evaluators [Intraclass Correlation Coefficient (ICC) range = 0.67 (unskilled) to 0.99 (experienced)] and between evaluators [ICC = 0.47 (unskilled), 0.85 (novice), 0.93 (experienced)]. The computer program had perfect reproducibility (ICC = 1.0). There was a significant relationship between the average of the experienced evaluators results and the custom program results (ICC = 0.77).

Conclusions

This study demonstrated that increased experience in cell counting resulted in increased reproducibility both within and between human evaluators but confirmed that the computer program was the most reproducible. There was a good correlation between the intact cell recovery determined by the computer program and the experienced human evaluators. The results of this study showed that the computer counting program was a reproducible tool to evaluate intact cell recovery after use of membrane integrity dyes on chondrocytes in situ. This and the significant decrease in the time used to count the cells by the computer program advocate its use in future studies because it has significant advantages.

     

Pleomorphic xanthoastrocytoma: what do we really know about it?

BACKGROUND: Pleomorphic xanthoastrocytomas (PXA) may recur and demonstrate aggressive clinical behavior with a mortality rate between 15% and 20%. To the authors' knowledge, no histopathologic features currently are known to reliably predict recurrence or tumor progression. METHODS: The study was based on 71 cases with available information regarding clinical and therapeutic data and follow-up. Diagnostic features included cellular pleomorphism, giant and/or xanthic cells, eosinophilic granular bodies, desmoplasia, and leptomeningeal involvement. The mitotic index (MI), the presence of necrosis, and endothelial proliferation were recorded in all primary resection specimens. RESULTS: The study included 35 females and 36 males, age 26+/-16 years (mean +/- standard deviation). Approximately 98% of tumors were supratentorial, with 49% in the temporal lobe. Seizures were the presenting symptoms in 71% of patients. Extent of tumor removal was macroscopic total resection in 68% of cases and subtotal resection (STR) in 32% of cases. Postoperative radiotherapy, alone or with chemotherapy, was administered in 29% and 12.5% of cases, respectively. The recurrence free survival rates (RFS) were 72% at 5 years and 61% at 10 years, whereas overall survivals rates (OS) were 81% at 5 years and 70% at 10 years. In univariate analysis, the extent of resection was the single factor associated most strongly with RFS (P=0.003), followed by MI (P=0.007) and atypical mitoses (P=0.04). Necrosis was not found to be significant. The extent of resection and MI were confirmed as independent predictors of RFS by multivariate analysis. MI (P=0.001), atypical mitoses (P=0.02), and necrosis (P=0.04) were associated with OS by univariate analysis. In multivariate analysis, only MI was an independent predictor of survival. Information regarding MIB-1 labeling index and the use of adjuvant therapy was too limited to explore their prognostic significance confidently. CONCLUSIONS: The study confirms that PXA is an astrocytic tumor with a relatively favorable prognosis. MI and extent of resection appear to be the main predictors of RFS and OS. Given the slow growth of the tumor, more studied cases and longer periods of follow-up will be essential to confirm our findings regarding prognostic factors affecting this unusual tumor.     

Epidermal cyst of the breast: Detection in a screening programme

Two cases of epidermal cyst of the breast, a rare benign condition, were detected during a 3-year period in a mammographic screening programme, from 57 954 screening examinations. It is not uncommon for epidermal cysts to be initially misdiagnosed. The mammographic, ultrasound and histological features are presented. It is recommended that these lesions be resected because they possibly have malignant potential.