Androgen receptor amplification is associated with increased cell proliferation in prostate cancer

Mechanisms of prostate cancer progression during hormonal therapy and the pathobiologic consequences of androgen receptor (AR) gene amplification are inadequately known. To further investigate the hypothesis that AR gene amplification is associated with increased cell proliferation, we analyzed 123 paraffin-embedded prostate cancer specimens from men who experienced tumor relapse during androgen withdrawal therapy. We used fluorescence in situ hybridization to quantify AR gene copy number and Ki-67 immunohistochemistry to determine cell proliferation. One third of the tumors showed AR gene amplification. Among tumors with AR amplification, the mean cell proliferation rate was 19.8 (SD, 12.3; 95% confidence interval [CI], 15.4-24.1), whereas it was 13.0 (SD, 15.9; 95% CI, 9.1-16.8) in tumors without amplification (P = .032). In the best fitting logistic regression model, only proliferation remained significant (P = .040). When the median Ki-67 labeling index (6.7%) of all tumors was used as a cutoff point, the tumors with AR amplification were more frequently highly proliferating than tumors with no amplification (P = .010; odds ratio, 3.4; 95% CI, 1.4-8.3). Our results imply that progression of prostate cancer during androgen withdrawal therapy is associated with AR gene amplification and increased cell proliferation rate in one third of tumors. We suggest that AR gene amplification is an important molecular mechanism underlying the increase in proliferation rate of a substantial fraction of recurrent prostate carcinomas. However, efforts should be targeted to develop prostate cancer cell lines to study causal relationships between AR gene amplification and various biologic variables.     

Population-based study of salivary carriage of periodontal pathogens in adults

Large, general population-based data on carriage rates of periodontal pathogens hardly exist in the current literature. The objectives of the present study were to examine the salivary detection of Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans, Campylobacter rectus, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis, and Treponema denticola in a representative sample of the adult population living in southern Finland and to clarify which determinants are associated with the presence of these pathogens in saliva. 16S rRNA-based PCR methods with species-specific primers were employed to determine the presence of the six target bacteria in stimulated saliva samples, which were available from 1,294 subjects aged > or =30 years. The age group, gender, level of education, marital status, smoking history, number of teeth, and number of teeth with deepened pockets were included in the statistical analysis. In general, the carriage of periodontal pathogens was common, since at least one of the examined pathogens was found in 88.2% of the subjects. In descending order, the total detection rates were 56.9%, 38.2%, 35.4%, 31.3%, 20.0%, and 13.9% for T. forsythensis, T. denticola, P. gingivalis, C. rectus, A. actinomycetemcomitans, and P. intermedia, respectively. Age per se was strongly associated with the carriage of P. gingivalis (P = 0.000), and the level of education with that of T. denticola (P = 0.000). There was an association between the number of teeth with deepened pockets and carriage of P. gingivalis (P = 0.000), P. intermedia (P = 0.000), T. denticola (P = 0.000), and A. actinomycetemcomitans (P = 0.004). The data suggest that distinct species have a different carriage profile, depending on variables such as age, educational level, and periodontal status.     

Effect of litter quality on foot pad dermatitis,hock burns and breast blisters in broiler breeders during the production period

Foot pad dermatitis and hock burn lesions are a form of contact dermatitis, a condition affecting skin areas in contact with unsuitable or irritating material. Contact dermatitis is a common problem, reducing the welfare of broilers, and is believed to also affect broiler breeders. However, there is very little research on contact dermatitis in breeders. This study followed the severity of foot pad lesions in broiler breeders throughout the production period. At slaughter the presence of hock burns and breast blisters was also determined. In addition, changes in litter condition over time and the impact of litter quality on foot pads were evaluated. The study was performed on 10 broiler breeder farms, including altogether 18 flocks. Foot pads of 100 hens per flock were assessed at the end of rearing period, three times during the production period, and at slaughter. Foot pad and hock lesions, as well as litter condition were scored on a 5-point scale. Litter quality was evaluated as pH, moisture and ammonia content. The condition of foot pads deteriorated towards slaughter age, with the occurrence of severe lesions reaching a maximum of 64% on average at slaughter. Hock lesions and breast blisters were rare. The litter layer became drier over time. Although poorer litter condition and wetness influenced foot pad health negatively, the effect on severe lesions was not significant. We also observed a negative effect on foot pad condition of larger slat areas. In conclusion, maintaining good litter quality alone is not enough to ensure healthy foot pads in broiler breeders.     

Accuracy of axillary staging using sentinel node biopsy or diagnostic axillary lymph node dissection--a case-control study

We aimed to compare the accuracy of axillary staging in breast cancer between sentinel node biopsy (SNB) and axillary lymph node dissection (ALND). The prevalence of axillary metastases was studied in 166 breast cancer patients with SNB and pair-matched control patients with ALND. The matching factors included age of the patient and grade, histological type and histological size of the tumour. There were 37% of patients with axillary metastases in the SNB group and 31% in the ALND group. Altogether, 57 pairs were discordant in relation to axillary metastases. In 34 discordant pairs the SNB patient and in 23 the ALND patient had axillary metastases, p=ns. Among the 36 discordant pairs with invasive ductal carcinoma (IDC), axillary metastases were detected as often in the SNB and the ALND patients. In the 21 discordant pairs with other histological types, the SNB patient had axillary metastases in 16 pairs and the ALND patient in 5 pairs, p<0.03. SNB seems to be as accurate a method for axillary staging as ALND. However, SNB generated no upstaging effect in IDC, only in other histological tumour types.     

Probing genomic diversity and evolution of Escherichia coli O157 by single nucleotide polymorphisms

Infections by Shiga toxin-producing Escherichia coli O157:H7 (STEC O157) are the predominant cause of bloody diarrhea and hemolytic uremic syndrome in the United States. In silico comparison of the two complete STEC O157 genomes (Sakai and EDL933) revealed a strikingly high level of sequence identity in orthologous protein-coding genes, limiting the use of nucleotide sequences to study the evolution and epidemiology of this bacterial pathogen. To systematically examine single nucleotide polymorphisms (SNPs) at a genome scale, we designed comparative genome sequencing microarrays and analyzed 1199 chromosomal genes (a total of 1,167,948 bp) and 92,721 bp of the large virulence plasmid (pO157) of eleven outbreak-associated STEC O157 strains. We discovered 906 SNPs in 523 chromosomal genes and observed a high level of DNA polymorphisms among the pO157 plasmids. Based on a uniform rate of synonymous substitution for Escherichia coli and Salmonella enterica (4.7x10(-9) per site per year), we estimate that the most recent common ancestor of the contemporary beta-glucuronidase-negative, non-sorbitolfermenting STEC O157 strains existed ca. 40 thousand years ago. The phylogeny of the STEC O157 strains based on the informative synonymous SNPs was compared to the maximum parsimony trees inferred from pulsed-field gel electrophoresis and multilocus variable numbers of tandem repeats analysis. The topological discrepancies indicate that, in contrast to the synonymous mutations, parts of STEC O157 genomes have evolved through different mechanisms with highly variable divergence rates. The SNP loci reported here will provide useful genetic markers for developing high-throughput methods for fine-resolution genotyping of STEC O157. Functional characterization of nucleotide polymorphisms should shed new insights on the evolution, epidemiology, and pathogenesis of STEC O157 and related pathogens.     

Human Neutrophil Defensins and Their Effect on Epithelial Cells

Background: The aims of the present study include: 1) to localize human neutrophil defensin‐1 (HNP‐1) through HNP‐3 in gingiva and in neutrophil extract‐treated epithelial cell monolayers; 2) to determine the effects of HNP‐1 on the epithelial cell viability, attachment, and spreading; and 3) to analyze the effect of HNP‐1 on the bacterial adherence to epithelial cells. Methods: For localization of HNP‐1 through HNP‐3 in gingival tissue and in preincubated cell monolayers, immunohistochemical and immunocytochemical methods were used. Viability and proliferation of epithelial cells were determined with commercial kits after incubating the keratinocytes with different HNP‐1 concentrations (low, 1 to 5 μg/mL; moderate, 10 μg/mL; high, 20 to 50 μg/mL). Attachment and spreading of keratinocytes on fibronectin‐coated surfaces in the presence of HNP‐1 were evaluated under microscope. Attachment of Fusobacterium nucleatum ATCC25586 and Prevotella intermedia ATCC25611 on keratinocytes preincubated with HNP‐1 were determined with a standard antibiotic test. Results: HNP‐1 through HNP‐3 localized in the junctional epithelium of clinically healthy gingiva and in the pocket epithelium of gingiva with periodontitis. When keratinocyte monolayers were incubated with neutrophil extracts, HNP‐1 through HNP‐3 were bound to the periphery of the growing cell colonies. In low HNP‐1 concentrations, the keratinocyte proliferation enhanced. Moderate and high concentrations of HNP‐1 increased the cellular death significantly. HNP‐1 increased the attachment and spreading of keratinocytes on fibronectin‐coated surfaces and bacterial attachment to keratinocytes in a concentration‐dependent manner. Conclusion: HNP‐1 plays a role in the integrity of keratinocytes by stimulating their proliferation, attachment, and spreading, whereas higher doses increase the bacterial attachment and keratinocyte death.     

The Effect of Small Variation of the Frequent Auditory Stimulus on the Event-Related Brain Potential to the Infrequent Stimulus

We investigated whether the mismatch process between a rare stimulus and the trace of frequent stimulus, which generates the mismatch-negativity component of the event-related potential, can tolerate a small variation in the intensity of the frequent stimulus. Series of short tone pips were presented to 10 subjects while they were reading a book and ignoring the auditory stimuli. The intensity (mean 80dB) of the frequent stimulus (600 Hz) varied within a range that was different in different blocks. The probability of the infrequent stimuli which were, in different blocks, either intensity deviants (600 Hz/70dB) or frequency deviants (650 Hz/80dB) was 10%. Both deviant stimuli elicited mismatch negativity even when the intensity of the frequent stimulus varied, although the amplitude of this component decreased with the increasing variability of the frequent stimulus. These results show that the generator process of mismatch negativity tolerates some variation in the repetitive stimulus, thus indicating that this process is also activated in ecologically more valid conditions. This is crucial to the interpretation of the generator process of mismatch negativity as a biologically vital warning mechanism.     

Unjustified CT examinations in young patients

The doses of radiation from computed tomography (CT) are relatively high, yet CT is being increasingly utilized. Furthermore, the radiation-induced lifetime risk of cancer mortality is higher at younger age. The purpose of this study was to find out whether previous CT examinations done on patients aged under 35 years were justified, and if not, whether there would have been other, more justifiable imaging modalities available. Fifty CT examinations of the head and 30 CT examinations each of the lumbar spine, cervical spine, abdomen, nasal sinuses and trauma were evaluated consecutively since the beginning of the year 2005 by using electronic patient files, the referral guidelines for imaging recommended by the European Commission and certain principles of classification. Seventy-seven per cent of the CT examinations of the lumbar spine, 36% of the head, 37% of the abdomen, 20% of the nasal sinuses and 3% of the cervical spine were unjustified. Most of these unjustified examinations could have been replaced by magnetic resonance imaging. In order to reduce utilization of ionizing radiation, both the referring practitioner and the radiologist responsible for the examination should carefully consider the justification for CT examinations and the possibility of using other imaging modalities.