Physical activity and colon cancer prevention: a meta-analysis

Although an inverse association between physical activity and risk of colon cancer is well established, a formal estimate of the magnitude of this risk reduction that includes recent studies is not available. This analysis examines the association by sex and study design, restricting analyses to studies where data for colon cancer alone were available. The authors reviewed published studies through June 2008 examining the association between physical activity and risk of colon cancer. Heterogeneity and publication bias were evaluated and random effects models used to estimate relative risks (RR). Differences by sex and study design were evaluated. A total of 52 studies were included. An inverse association between physical activity and colon cancer was found with an overall relative risk (RR) of 0.76 (95% confidence interval (CI): 0.72, 0.81). For men, the RR was 0.76 (95% CI: 0.71, 0.82); for women, this was little different, (RR=0.79, 95% CI: 0.71, 0.88). The findings from case-control studies were stronger (RR=0.69, 95% CI: 0.65, 0.74) than for cohort studies (RR=0.83, 95% CI: 0.78, 0.88). This study confirms previous studies reporting an inverse association between physical activity and colon cancer in both men and women, and provides quantitative estimates of the inverse association.

Protection mechanisms against Abeta42 aggregation

It is widely accepted that Abeta42 aggregation is a central event in the pathogenesis of Alzheimer's disease. Abeta42 oligomers and fibrils cause the breakdown of neural circuits, neuronal death and eventually dementia. There are a number of physiological molecules that can protect Abeta42 from aggregation. Promoting such protective molecules and mechanisms against Abeta42 aggregation may be a novel direction in AD drug discovery. One of the most striking protective molecules is none other than Abeta40, which inhibits Abeta42 aggregation in a specific and dosage dependent manner. Abeta40 is a critical, built-in mechanism against Abeta42 aggregation. A number of other molecules and mechanisms also inhibit Abeta42 aggregation, such as heat shock proteins, L-PGDS, heme and methionine oxidation. The relevance of these protective mechanisms to AD pathogenesis and intervention is discussed.

Multi-modality imaging of N-methyl-N-nitrosourea-induced mammary tumors by MRI and small animal PET

Abstract #6008

Background: We evaluated the use of high resolution Magnetic Resonance Imaging (MRI) and small animal Positron Emission Tomography (PET) imaging in assessing tumor proliferation and response to therapy in N-methyl-N-nitrosourea (MNU)-induced mammary tumors.
 Materials and Methods: The study comprised of 30 untreated MNU rats, 6 Targretin-treated MNU rats, and 6 Vorozole-treated MNU rats. Rats received a baseline imaging session when they developed their first palpable mammary tumor and were subsequently randomized into a control group or a treatment group with either Targretin (220mg/kg in the diet) or Vorozole (1.25mg/kg body weight by gavage). Treatment lasted for 8 weeks following the baseline imaging session. Each rat was imaged for 10-weeks at 2-week intervals with a) FDG to assess the metabolic state of tumors, b) MRI to monitor tumor volume, and c) [18F]ISO-1, a Sigma-2 radiolabeled ligand, to assess the proliferative status of MNU-induced tumors. Static images (10-minute) were obtained 60-minutes post-injection of FDG and [18F]ISO-1. In untreated tumors, a minimum of 40 PET outcome measures were assessed for their ability to predict changes in MRI-derived volume measurements between consecutive imaging sessions. In addition, regression analysis was performed to assess the correlation (R) between the measures. In treated tumors, the time-course of changes in PET outcome measures relative to baseline was evaluated to assess the efficacy of Targretin and Vorozole, in particular in characterizing short-term response (initial 2-weeks) and response to treatment withdrawal (weeks 8-10).
 Results: An index characterizing a MRI-normalized [18F]ISO-1 uptake significantly correlated (R=0.7, P<0.0003) with changes in tumor volume between consecutive imaging sessions in untreated tumors. In contrast, there was no correlation between FDG outcome measures and changes in tumor volume. Targretin had the strongest short-term efficacy with a reduction in tumor load, on average, by as much as 60% compared with Vorozole's 20% reduction in tumor load. We observed higher rate of tumor resurgence in rats treated with Vorozole compared with Targretin, suggesting a residual effect of Targretin. In general, PET outcome measures of both FDG and [18F]ISO-1 delineated short-term response to treatment and non-responding tumors. [18F]ISO-1 was more sensitive than FDG in capturing tumor growth following treatment withdrawal at week 8.
 Conclusion: MRI and small animal PET provide a platform to assess MNU-induced tumor proliferation and the efficacy of therapeutic interventions non-invasively, as demonstrated in this work.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6008.

Measurement of the e;{+}e;{-}-->bb[over ] Cross Section between sqrt[s]=10.54 and 11.20 GeV

We report e;{+}e;{-}-->bb[over ] cross section measurements by the BABAR experiment performed during an energy scan in the range of 10.54 to 11.20 GeV at the SLAC PEP-II e;{+}e;{-} collider. A total relative error of about 5% is reached in more than 300 center-of-mass energy steps, separated by about 5 MeV. These measurements can be used to derive precise information on the parameters of the Upsilon(10860) and Upsilon(11020) resonances. In particular we show that their widths may be smaller than previously measured.

Transformation of nitrogen and distribution of nitrogen-related bacteria in a polluted urban stream

Most researchers focused on either nitrogen species or microbial community for polluted urban stream while ignoring the interaction between them and its effect on nitrogen transformation, which restricted the rational selection of an effective and feasible remediation technology. Taking Buji stream in Shenzhen (China) as target stream, the distribution of nitrogen-related bacteria was investigated by most probable number (MPN) besides analysis of nitrogen species etc. The nitrogen-related bacteria in sediment were 10(2) times richer than those in water. Owing to their faster growth, the MPN of ammonifying bacteria and denitrifying bacteria were 10(5) and 10(2) times higher than those of nitrifying bacteria, respectively. The ammonifying bacteria numbers were significantly related to BOD5 in water, while nitrifying bacteria in sediment correlated well with nitrate in water. Thus, nitrification occurred mainly in sediment surface and was limited by low proportion of nitrifying bacteria. The denitrifying bacteria in sediment had good relationship with BOD5 and nitrite and nitrate in water. Low DO and rich organic compounds were beneficial to denitrification but unfavourable to nitrification. Denitrification was restricted by low nitrite and nitrate concentration. These results could be served as a reference for implementing the remediation scheme of nitrogen polluted urban stream.

Predictors of disease-free survival in rectal cancer patients undergoing curative proctectomy

OBJECTIVE

To identify the factors that affect the disease-free survival (DFS) of rectal cancer patients.

METHOD

Patients from an IRB approved rectal cancer database were reviewed (1990-2000). All patients underwent either abdominoperineal resection or low anterior resection using total mesorectal excision with curative intent. Univariate and multivariate analyses were performed to analyse the factors that influenced DFS.

RESULTS

A total of 304 patients were reviewed (mean age 64, 52% male). Seventy-seven per cent of patients received neoadjuvant therapy (28.6% short-course radiation therapy (RT), 35.5% long-course RT, 12.5% chemo-RT). The radial margin was involved with tumour in 5.2% of patients (final pathology). The overall survival rate was 85.2% with a mean follow-up time of 33 +/- 26 months. The mean time to death was 34.8 +/- 26.8 months. Local recurrence (+/- distant recurrence) occurred in 4%. Anastomotic leaks occurred in 3.6% of patients. Overall pathologic stage, pathologic T stage, nodal status, the use of adjuvant chemotherapy, tumour fixation, involvement of the radial margin, the presence of mucin, and lymphatic and perineural invasion (PNI) were predictors of DFS by univariate analysis. Of note, anastomotic leaks and obstructing cancers did not influence DFS. Using multivariate analysis with backward elimination, overall pathologic stage, radial margin status, adjuvant chemotherapy, and PNI predicted the DFS.

CONCLUSION

Major predictors of DFS in rectal cancer are the overall pathologic stage, adjuvant chemotherapy, radial margin status and PNI. Radial margin status may be a marker of tumour aggressiveness and should be considered in deciding on adjuvant chemotherapy.

Observation of the bottomonium ground state in the decay Upsilon(3S)-->gammaetab

We report the results of a search for the bottomonium ground state etab(1S) in the photon energy spectrum with a sample of (109+/-1) million of Upsilon(3S) recorded at the Upsilon(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at Egamma=921.2(-2.8)+2.1(stat)+/-2.4(syst) MeV with a significance of 10 standard deviations. We interpret the observed peak as being due to monochromatic photons from the radiative transition Upsilon(3S)-->gammaetab(1S). This photon energy corresponds to an etab(1S) mass of 9388.9(-2.3)+3.1(stat)+/-2.7(syst) MeV/c2. The hyperfine Upsilon(1S)-etab(1S) mass splitting is 71.4(-3.1)+2.3(stat)+/-2.7(syst) MeV/c2. The branching fraction for this radiative Upsilon(3S) decay is estimated to be [4.8+/-0.5(stat)+/-1.2(syst)]x10(-4).

Identification of the N-linked glycosylation sites of the human relaxin receptor and effect of glycosylation on receptor function

The relaxin receptor, RXFP1, is a member of the leucine-rich repeat-containing G-protein-coupled receptor (LGR) family. These receptors are characterized by a large extracellular ectodomain containing leucine-rich repeats which contain the primary ligand binding site. RXFP1 contains six putative Asn-linked glycosylation sites in the ectodomain at positions Asn-14, Asn-105, Asn-242, Asn-250, Asn-303, and Asn-346, which are highly conserved across species. N-Linked glycosylation is the most common post-translational modification of G-protein-coupled receptors, although its role in modulating receptor function differs. We herein investigate the actual N-linked glycosylation status of RXFP1 and the functional ramifications of these post-translational modifications. Site-directed mutagenesis was utilized to generate single- or multiple-glycosylation site mutants of FLAG-tagged human RXFP1 which were then transiently expressed in HEK-293T cells. Glycosylation status was analyzed by immunoprecipitation and Western blot and receptor function analyzed with an anti-FLAG ELISA, (33)P-H2 relaxin competition binding, and cAMP activity measurement. All of the potential N-glycosylation sites of RXFP1 were utilized in HEK-293T cells, and importantly, disruption of glycosylation at individual or combinations of double and triple sites had little effect on relaxin binding. However, combinations of glycosylation sites were required for cell surface expression and cAMP signaling. In particular, N-glycosylation at Asn-303 of RXFP1 was required for optimal intracellular cAMP signaling. Hence, as is the case for other LGR family members, N-glycosylation is essential for the transport of the receptor to the cell surface. Additionally, it is likely that glycosylation is also essential for the conformational changes required for G-protein coupling and subsequent cAMP signaling.

Understanding the differences between the wear of metal-on-metal and ceramic-on-metal total hip replacements

Hip simulator studies have been carried out extensively to understand and test artificial hip implants in vitro as an efficient alternative to obtaining long-term results in vivo. Recent studies have shown that a ceramic-on-metal material combination lowers the wear by up to 100 times in comparison with a typical metal-on-metal design. The reason for this reduction remains unclear and for this reason this study has undertaken simple tribometer tests to understand the fundamental material loss mechanisms in two material combinations: metal-on-metal and ceramic-on-ceramic.

A simple-configuration reciprocating pin-on-plate wear study was performed under open-circuit potential (OCP) and with applied cathodic protection (CP) in a serum solution using two tribological couples: firstly, cobalt—chromium (Co—Cr) pins against Co—Cr plates; secondly, Co—Cr pins against alumina (Al2O3) plates. The pin and plate surfaces prior to and after testing were examined by profilometry and scanning electron microscopy.

The results showed a marked reduction in wear when CP was applied, indicating that total material degradation under the OCP condition was attributed to corrosion processes. The substitution of the Co—Cr pin with an Al2O3 plate also resulted in a dramatic reduction in wear, probably due to the reduction in the corrosion—wear interactions between the tribological pair.

Effect of inhaled formaldehyde on learning and memory of mice

In this study, we investigated the effect of inhaled formaldehyde on learning and memory capacity. After exposure to 0 (control), 1 and 3 mg/m(3) of gaseous formaldehyde respectively, the behavior of mice in a Morris water maze, the expression of NR1, NR2B mRNA and oxidative damage levels in mice brain were analyzed. The water maze performance, the activities of dismutase superoxide (SOD) and levels of glutathione (GSH) decreased significantly in 3 mg/m(3) group (P < 0.01, compared with control group); while malondialdehyde (MDA) contents and expression of NR1 and NR2B genes increased significantly after exposure to 3 mg/m(3) of gaseous formaldehyde (P < 0.05, <0.01, <0.01, compared with control group). These findings indicate that inhaled formaldehyde negatively affects learning and memory at 3 mg/m(3) of gaseous formaldehyde but not at lower levels. Oxidative stress-induced neuron damages in the brain may be the possible mechanism for these effects.

PRACTICAL IMPLICATIONS

This study indicates that inhaled formaldehyde starts to negatively affect learning and memory at a middle concentration of formaldehyde without interference of other indoor air pollutants. Oxidative damage, and the alteration of NMDA receptor expression, which were induced by formaldehyde inhalation, may be the possible mechanism for gaseous formaldehyde-induced neurotoxicity.

Immunological properties of a fusion protein containing nucleocapsid protein and glycoprotein Gn of Hantaan virus

Escherichia coli and the baculovirus Bac-to-Bac system were used to express chimeric gene GnS0.7 consisting of glycoprotein Gn gene and the 0.7 kb fragment of S genome segment carrying nucleoprotein (N) gene of Hantaan virus (HTNV). The expressed fusion protein GnN0.7 was recognized by monoclonal antibodies (MAbs) to HTNV Gn glycoprotein and N protein, respectively. Its molecular mass as determined by Western blot analysis corresponded to the predicted value. The mice immunized with insect Spodoptera frugiperda (Sf9) cells transfected with recombinant baculovirus carrying GnS0.7 gene, produced serum antibodies with titer up to 3,200 as assayed by immunofluorescence. Moreover, immunized mice showed positive proliferation index for splenocytes stimulated with HTNV Gn and N, respectively. These results indicated that insect Sf9 cells infected with the recombinant baculovirus expressed a fully biologically active fusion protein that elicited not only humoral but also cellular immune response in mice. Hence, this protein may be used as a genetically engineered subunit HTNV vaccine representing efficacious and safe alternative to traditional vaccines.

Regulation of class IA PI3Ks

Class IA PI3Ks (phosphoinositide 3-kinases) regulate a wide range of cellular responses through the production of PI(3,4,5)P(3) (phosphatidylinositol 3,4,5-trisphosphate) in cellular membranes. They are activated by receptor tyrosine kinases, by Ras and Rho family GTPases, and in some cases by G(betagamma) subunits from trimeric G-proteins. Crystallographic studies on the related class IB PI3Kgamma, and biochemical and structural studies on the class IA PI3Ks, have led to new insights into how these critical enzymes are regulated in normal cells and how mutations can lead to their constitutive activation in transformed cells. The present paper will discuss recent studies on the regulation of class I (p85/p110) PI3Ks, with a focus on the role of SH2 domains (Src homology 2 domains) in the p85 regulatory subunit in modulating PI3K activity.

A novel unconventional antigen MPD5 elicits anti-tumor humoral immune responses in a subset of patients with polycythemia vera

In an effort to define the antigenic mechanism that contributes to beneficial therapeutic outcome in patients with polycythemia vera (PV), we screened a human testis cDNA library with serological cloning derived from sera of three PV patients who had undergone therapeutic-induced remission. As a result, we identified a novel antigen, MPD5, which belongs to the group of cryptic antigens with unconventional genomic intron/exon structure. Moreover, MPD5 elicited IgG antibody responses in a subset of PV patients who had benefited from a variety of therapies--including IFN-alpha, Hydroxyurea, Imatinib mesylate, Anagrelide, and phlebotomy--but not in untreated PV patients or healthy donors, suggesting that MPD5 is a PV-associated, therapy-related antigen. In the granulocytes of PV patients who are responsive to therapy, upregulated MPD5 expression may serve to enhance immune responses. These findings provide new insight into the mechanism underlying regulation of the self-antigen repertoire that elicits anti-tumor immune responses in patients with myeloproliferative diseases, indicating the potential of these self-antigens as targets of novel immunotherapy.