A comparison of 24 chemicals in the six-well bacterial reverse mutation assay to the standard 100-mm Petri plate bacterial reverse mutation assay in two laboratories.

The bacterial reverse mutation assay (Ames) is a fundamental genetic toxicology test, and efforts to miniaturize the regulatory GLP version are essential in assessing genotoxic liabilities earlier in the drug development pipeline. Two versions of the Ames were compared: the six-well (miniaturized) plate and the standard 100-mm plate test at two different laboratories. Of twenty-four chemicals tested, a subset of six chemicals was tested in the six-well test only and the remaining eighteen were evaluated in both versions of the test. The plate incorporation procedure was used with one Escherichia coli and four different Salmonella strains. The six-well test uses the same plating procedure and evaluation methods as the standard Ames assay in 100-mm plates, but the smaller format requires 20% of the test chemical. Additionally, the six-well test uses a limit concentration of 1000 µg/well versus the standard Petri plate test limit concentration of 5000 µg/plate. Testing across the two formats resulted in 100% concordance in overall mutagenicity judgement and 94% concordance across all tester strains and conditions. Known mutagenic positive control chemicals were correctly detected as positive in both formats. The overall conclusion is that the six-well assay results are concordant with the standard assay format in this evaluation and could be a reliable alternative.

Colectomy without mechanical bowel preparation in the private practice setting.

BACKGROUND: Despite randomized trials and meta-analyses demonstrating the safety of omitting mechanical bowel preparation (MBP) before colorectal surgery, private practice surgeons may hesitate to eliminate MBP for fear of being outside community standards. This study evaluated the safety of eliminating MBP before colectomy in a private practice setting. METHODS: This prospective observational study included elective abdominal colorectal operations from one surgeon's practice from October 2008 to June 2011. MBP was not routinely utilized after November 2009. Postoperative 30-day complication rates and length of hospital stay were compared in patients with and without MBP. Multivariable regression models were developed to compare outcomes among study groups, adjusting for demographics, diagnoses, procedures, and year. RESULTS: A total of 165 patients were analyzed. Demographics were similar between groups. Laparoscopic procedures were more common in patients without MBP due to increased laparoscopy over time (43 vs. 61 %, p = 0.03). As regards complications, infection rates were similar between groups (MBP 10.5 % vs. no MBP(NMBP) 11.4 %, adj p = 0.57). Patients without MBP had a shorter length of hospital stay (median: 6 vs. 5 days, p = 0.01), but those differences were not statistically significant after adjustment (p = 0.14). CONCLUSIONS: Private practice surgeons should embrace evidence-based practice changes and make efforts to quantitatively evaluate the safety of those changes. Omission of MBP for most elective colectomy procedures appears to be safe with no significant increase in complications or length of hospital stay. Because MBP has substantial drawbacks, there is little justification for its routine use in the majority of elective abdominal colorectal procedures.

Effect of feed type and sex on digestibility and feed efficiency utilization in black spiny-tailed iguana (Ctenosaura pectinata).

Digestibility, feed efficiency, and the effect of sex were evaluated in black iguanas (Ctenosaura pectinata) using two commercial pellets (rabbit and chicken). The experiment was performed in 80 iguanas in a completely randomized design with a factorial arrangement 2×2 over 105 days. No differences were detected by food type in weight gain (chicken vs. rabbit: 121 vs. 154 mg/d) and daily intake (chicken vs. rabbit: 524 vs. 551 mg/d), but differences were detected (P<0.05) in feed conversion (chicken vs. rabbit: 6.45 vs. 4.47). Rabbit pellets showed higher digestibility than chicken food (P<0.01) in dry matter (59.8 vs. 41.4%) and NDF (55.4 vs. 43.6%), respectively. Sex had no effect in any of the variable responses. Black iguanas can be raised since 6 months old in captivity with commercial food designed for rabbit or broiler. No special physiological adaptations occur in black iguanas correlated with change in feeding habits during ontogeny.

Human temporomandibular joint eminence shape and load minimization.

Analysis of previous data suggested the hypothesis that temporomandibular joint (TMJ) eminence shapes develop ideally to minimize joint loads. Hence, we tested this hypothesis in nine females and eight males in each of two groups, with and without TMJ disc displacement. Participants provided anatomical data used in a joint load minimization numerical model to predict, and jaw-tracking data used to measure, eminence shapes. Coordinate data (x,y) of shapes were fit to third-order polynomials for two sessions, sides, and methods (predicted, measured) for each participant. Inter-session data were reliable and averaged. Those with, compared with those without, disc displacement had higher measured shape range (5:1) and left-right asymmetry prevalence (4:1). In 29 symmetrical individuals, ANCOVA and Bonferroni tests compared vertical dimensions (y) at 11 postero-anterior points (x), 0.5 mm apart. Model-predicted and measured shapes were significantly different (P < or = 0.01) near the eminence crest, but joint load minimization was consistent with eminence shape for x < 3.0 mm.

Three new species of philometrids (Nematoda: Philometridae) from centrarchid fishes in the USA.

The following 3 new species of the Philometridae (Nematoda: Dracunculoidea) are described from freshwater centrarchid fishes (Centrarchidae: Perciformes) from eastern North America on the basis of museum and newly collected specimens: Philometra orbitalensis n. sp. and Philometroides aphanonaris n. sp. from the oculo-orbits and subcutaneous tissues of the head, respectively, of the largemouth bass Micropterus salmoides, and Philometroides wellborni n. sp. from the oculo-orbits of the bluegill Lepomis macrochirus (type host) and the redbreast sunfish Lepomis auritus. Whereas P. wellborni is described from both males and gravid females, the males of P. aphanonaris and P. orbitalensis remain unknown. The type locality of all 3 species is the West Point Reservoir, Alabama-Georgia; P. aphanonaris and P. wellborni have also been recorded from the Santee River in South Carolina. In contrast to other Philometra spp. parasitizing North American freshwater fishes, the gravid females of P. orbitalensis are characterized by large cephalic papillae of the external circle, yellowish body color, location (oculo-orbits) in the host, and by the host type (Centrarchidae). Philometroides aphanonaris and P. wellborni differ from North American congeners from freshwater fishes in the absence of esophageal teeth or a different embossment of the caudal end in gravid females; P. wellborni differs from P. aphanonaris in the absence of cuticular bosses from the caudal end of gravid females and in some other features (extent of embossment, body color, location, and host type).

E2F4 regulates a stable G2 arrest response to genotoxic stress in prostate carcinoma.

The retinoblastoma (pRB) family proteins regulate the E2F transcription factors; their complexes regulate critical transitions through the cell cycle. The function of these pRB family/E2F complexes, which includes p130/E2F4, in response to genotoxic agents, is not well understood. We investigated the role of E2F4 in the genotoxic stress response. Following radiation treatment, E2F4 colocalized with p130 in the nucleus during a radiation-induced stable G(2)-phase arrest. Arrested cells had significantly decreased expression of Cyclins A2 and B1 and decreased phosphorylation of mitotic protein monoclonal-2 (MPM-2) mitotic proteins. Small interference RNA (siRNA)-mediated knockdown of E2F4 sensitized cells to subsequent irradiation, resulting in enhanced cellular DNA damage and cell death, as determined by caspase activation and decreased clonogenic cell survival. Downstream E2F4 targets potentially involved in the progression from G(2) into M phase were identified by oligonucleotide microarray expression profiling. Chromatin immunoprecipitation localized E2F4 at promoter regions of the Bub3 and Pttg1 mitotic genes following irradiation, which were among the downregulated genes identified by the microarray. These data suggest that in response to radiation, E2F4 becomes active in the nucleus, enforces a stable G(2) arrest by target gene repression, and thus provides increased cell survival ability by minimizing propagation of cells that have irreparable DNA damage.

Effect of selenium-vitamin E injection in selenium-deficient dairy goats and kids on the Mexican plateau

Foram conduzidos três experimentos para determinar a quantidade ótima da injeção de selênio-vitamina E (Se-vit E) para manter o nível aceitável do status de selênio no sangue de cabras e cabritos e determinar essa relação com o status sobre a taxa de mortalidade de cabritos. No primeiro experimento, 238 cabras foram usados em um dos três grupos durante o período do acasalamento: A1- controle, A2- 0,06mgSe+0,8UI vitE/kg de peso-vivo e A3- 0,125mgSe+1,7UI vitE/kg de peso-vivo. Não houve diferenças (P>0,05) entre os grupos para fertilidade e prolificidade. A concentração de Se no sangue não foi diferente entre os grupos que receberam Se-vit E e o controle antes da injeção e ambos os grupos mostravam deficiência de Se. Sessenta dias pós-tratamento houve tendência (P<0,05; 32%) de aumentar o nível de Se no sangue e não houve diferença entre os grupos A2 e controle. Houve diferença significativa (P<0,05; 103%) entre os grupos A1 e A2 e o grupo A3. No segundo experimento, 48 cabras foram divididas em quatro grupos: B1- controle, B2- 0,125mgSe+1,7UI vitE/kg de peso-vivo, B3- 0,25mgSe+3,4UI vitE/kg de peso-vivo e B4- 0,31mgSe+4,2UI vitE/kg de peso-vivo. O grupo B4 alcançou a concentração mais alta no terceiro mês depois da injeção (0,11ppm) e diminuiu depois de 100 dias, quando o valor foi apenas ligeiramente maior que os valores dos grupos B2 e B3, aos 135 dias da gestação. Os resultados dos grupos B2 e B3 foram ligeiramente mais altos que os do grupo B1 (P<0,05). No terceiro experimento, 194 cabritos (3 a 7 dias de idade), nascidos de cabras deficientes em Se, foram usados para comparar a efetividade da injeção de Se. Foram divididos em três grupos: C1- controle, C2- 0,3mgSe+4,2UI vitE/kg de peso-vivo e C3- 0,6mgSe+8,4UI vit E/kg de peso-vivo. A porcentagem de mortalidade foi mais alta em C1 (60%) e mais baixa nos grupos tratados com Se (22%). A concentração de Se no sangue no 20º após o início do tratamento aumentou rapidamente, de acordo com o nível de injeção de Se. A injeção com 0,3mgSe/kg de peso-vivo aumentou a concentração de Se no sangue em cabras gestantes e a dose foi efetiva para prevenir a doença de músculo branco e aumentar a sobrevivência dos cabritos até o desmame.

Genetics of ethylene biosynthesis and restriction fragment length polymorphisms (RFLPs) of ACC oxidase and synthase genes in melon ( Cucumis melo L.).

We investigated the genetics of ethylene biosynthesis and its linkage to the RFLPs of the ACC oxidase and synthase genes in melon ( Cucumis melo L.). The results suggested that the A(0) and B(0) fragments of RFLP-MEL1 of the ACC oxidase gene were two alleles from a single locus, as were the B and C fragments of RFLP-MEACS1 of the ACC synthase gene. The B(0) allele seemed to be partially dominant over the A(0) allele, whereas B and C alleles appeared to map to quantitative trait loci (QTLs), which most likely contributed to ethylene production. Both RFLPs were linked to ethylene production rates, but they were not linked to each other. The interaction effects of the ACC oxidase and synthase genes on ethylene production were revealed by segregation of RFLP-MEL1 and RFLP-MEACS1. The results of single-copy-reconstruction assays suggested that the ACC oxidase gene is a single copy, whereas the ACC synthase gene is a component of a multigene family in the melon genome. The abscission phenotype appeared to be controlled by an independent locus, with the abscission (full-slip) allele dominant over the non-abscission (not full-slip) allele. These results may facilitate efforts toward mapping the quantitative trait loci (QTLs) of ethylene production. The RFLPs may be used in marker-assisted selection in developing melons with a more-desirable low ethylene production rate for enhancing postharvest storage life.

Apollo: a sequence annotation editor.

The well-established inaccuracy of purely computational methods for annotating genome sequences necessitates an interactive tool to allow biological experts to refine these approximations by viewing and independently evaluating the data supporting each annotation. Apollo was developed to meet this need, enabling curators to inspect genome annotations closely and edit them. FlyBase biologists successfully used Apollo to annotate the Drosophila melanogaster genome and it is increasingly being used as a starting point for the development of customized annotation editing tools for other genome projects.

Relationships between the shedding of Coxiella burnetii, clinical signs and serological responses of 34 sheep.

Two abortions associated with Coxiella burnetii occurred in a group of 34 pregnant ewes. The seroprevalence of C. burnetii infection was studied by using an ELISA and the immunofluorescence (IF) assay was applied to the contents of vaginal swabs. In addition, a PCR assay, with primers based on a transposon-like repetitive region of the C. burnetii genome (trans-PcR), was used for the highly sensitive and specific detection of C. burnetii in vaginal swabs, milk and faeces. Of the 34 animals tested at parturition, eight (24 per cent) were positive by ELISA, 11 (32 per cent) were positive by IF, and 15 (44 per cent) were positive when the vaginal swab extract was subjected to the trans-PCR assay. C. burnetii was therefore detected by PCR in the vaginal swabs of seven seronegative ewes. However, five weeks after lambing, 16 (47 per cent) of the animals tested were ELISA positive but only two animals (6 per cent) were positive by PCR. Among the ELISA- and PCR-positive animals, eight (25 per cent) shed coxiella in their milk and six (18 per cent) did so in their faeces.

Reliable short-term memory in the trion model: toward a cortical language and grammar.

It has previously been shown that Hebb learning in a single column in the trion model of cortical organization occurs by selection. Motivated by von Neumann's solution for obtaining reliability and by models of circulating cortical activity, we introduce Hebb intercolumnar couplings to achieve dramatic enhancements in reliability in the firing of connected columns. In order for these enhancements to occur, specific temporal phase differences must exist between the same inherent spatial-temporal memory patterns in connected columns. We then generalize the criteria of large enhancements in the global firing of the entire connected columnar network to investigate the case when different inherent memory patterns are in the columns. The spatial rotations as well as the temporal phases now are crucial. Only certain combinations of inherent memory patterns meet these criteria with the symmetry properties playing a major role. The columnar order of these memory patterns not in the same symmetry family can be extremely important. This yields the first higher-level architecture of a cortical language and grammar within the trion model. The implications of this result with regard to an innate human language and grammar are discussed.

Prostaglandin J(2) inhibition of mesangial cell iNOS expression.

Mesangial cells from MRL/lpr mice, a model of lupus, overproduce nitric oxide (NO) compared to controls. J series prostaglandins (PG) and thiazolidinediones block LPS stimulation of NO production via the activation of peroxisome proliferator-activator receptor-gamma (PPAR-gamma) in macrophages but utilize an alternative mechanism in microglial cells. We investigated the mechanism by which PGJ(2) inhibits NO production in LPS/IFN-gamma-stimulated MRL/lpr mesangial cells. Our results demonstrated that LPS/IFN-gamma addition to MRL/lpr mesangial cells stimulated iNOS activation, expression of p-38 kinase and p44/42 MAPK, and NF-kappaB translocation to the nucleus. Both pioglitazone, a specific PPAR-gamma agonist, and PGJ(2) blocked NO production, iNOS protein expression, and iNOS mRNA transcription. PGJ(2) failed to inhibit nuclear NF-kappaB translocation or p44/42 MAPK or p-38 kinase induction in stimulated mesangial cells. These data suggest that PGJ(2) blocks iNOS expression and subsequent NO production in mesangial cells via a PPAR-gamma-mediated mechanism either by interfering with NF-kappaB transcriptional activity or by an NF-kappaB-independent mechanism.

The practices and attitudes of primary care nurse practitioners and physician assistants with respect to colorectal cancer screening.

OBJECTIVES: Although nurse practitioners and physician assistants form a large and growing portion of the primary care workforce, little is known about their colorectal cancer screening practices. The aim of this study was to assess the colorectal cancer screening practices, training, and attitudes of nurse practitioners and physician assistants practicing primary care medicine. METHODS: All nurse practitioners (827) and physician assistants (1178) licensed by the Medical Board of the State of North Carolina were surveyed by mail. Both groups were further divided into primary care versus non-primary care by self-described roles. Self-reported practices, training, and attitudes with respect to colorectal cancer screening were elicited. RESULTS: Response rates were 71.4% and 61.2%, for nurse practitioners and physician assistants respectively. A total of 51.3% of nurse practitioners and 50.3% of physician assistants described themselves as adult primary care providers. No primary care nurse practitioners and only 3.8% of primary care physician assistants performed screening flexible sigmoidoscopy. However, 76% of primary care physician assistants and 69% of primary care nurse practitioners reported recommending screening flexible sigmoidoscopy. A total of 95% primary care physician assistants and 92% of primary care nurse practitioners reported performing fecal occult blood testing. Only 9.4% of physician assistants and 2.8% of nurse practitioners received any formal instruction in flexible sigmoidoscopy while in their training. Additionally, 41.4% of primary care physician assistants and 27.7% of primary care nurse practitioners reported that they would be interested in obtaining formal training in flexible sigmoidoscopy. CONCLUSIONS: Physician assistants and nurse practitioners are motivated, willing and underutilized groups with respect to CRC screening. Efforts to increase education and training of these professionals may improve the availability of CRC screening modalities.

An introduction to statistical inference--3.

Statistics inference is used to make comments about a population based upon data from a sample. In a similar manner it can be applied to a population to make an estimate about a sample. It is commonly seen in medical publications when the null hypothesis is being tested. This calculates the probability (p value) of a type I error--that is, that a particular finding is attributable to chance. It is also important to be aware of the chances of a type II error--that is, accepting the null hypothesis when it does not apply. Sample size, point estimate and variability are common factors that will affect the chances of making these two types of errors. Interpreting results therefore needs to take these factors into account as well as the clinical relevance of the findings. Statistical significance does not necessarily mean clinical significance.

Is there publication bias in the reporting of cancer risk in Barrett's esophagus?

BACKGROUND & AIMS: The published risk of adenocarcinoma in the setting of Barrett's esophagus (BE) varies. Publication bias, the selective reporting of studies featuring positive or extreme results, may result in overestimation of this cancer risk in the literature. The aim of this study was to assess those publications reporting a cancer risk in BE for evidence of publication bias. METHODS: A MEDLINE search for all published estimates between 1966 and 1998 of cancer risk in BE was performed. All studies reporting a cancer risk expressible in cancers per patient-year of follow-up were retrieved. Bibliographies of these studies were surveyed for additional estimates. All publications that required an initial endoscopy with histologic confirmation of BE and any cancer were included. The relationship of reported cancer risk to size of the study was assessed. Multivariable regression controlling for differences in definition of BE, as well as other study characteristics, was performed. The data were also analyzed by means of a funnel diagram, an epidemiologic method to assess publication bias. RESULTS: Five hundred fifty-four abstracts were reviewed. Twenty-seven publications met the stated criteria for inclusion. There was a strong correlation between cancer risk and the size of the study, with small studies reporting much higher risks of cancer than larger studies. This association persisted when differences in the definition of BE, retrospective vs. prospective nature of the study, surveillance interval, and the effect of cancer detected in the first year were considered. The funnel diagram analysis suggested publication bias. CONCLUSIONS: The cancer risk in BE may be overestimated in the literature due to publication bias.