Emergence of resistance to fluoroquinolones and third-generation cephalosporins in Shigella flexneri subserotype 1c isolates from China

We report here on the first identification of Shigella flexneri subserotype 1c in China. We also report the emergence of resistance to ciprofloxacin and third-generation cephalosporins in this subserotype 1c for the first time. Isolates of seven strains circulating in China yielded three new sequence types and seven pulsed-field gel electrophoresis patterns, thus demonstrating the existence of high genetic diversity within the isolates. Overall, the seven isolates showed reduced susceptibility to ciprofloxacin; one isolate was ciprofloxacin resistant, whilst another developed resistance to ciprofloxacin, norfloxacin, cefotaxime and ceftriaxone.

Effect of risedronate on osteocyte viability and bone turnover in paired iliac bone biopsies from early postmenopausal women

It is unclear whether standard clinical doses of risedronate affect osteocyte viability. This study examined osteocyte viability and bone remodeling rate in early postmenopausal women (1-5 years after menopause) who were treated with a standard clinical dose of risedronate (5 mg/day, orally) for 1 year. Paired transiliac bone biopsies were obtained from 19 postmenopausal women at baseline and after 1-year treatment with placebo (n = 8, mean age 52.9 ± 3.4 years) or risedronate 5 mg/day (n = 11, mean age 52.5 ± 3.4 years). In these samples, we measured osteocyte- and bone remodeling-related variables in trabecular bone. In both the placebo and risedronate groups, empty lacunae were significantly decreased after 1-year treatment compared to baseline. There were no significant differences in osteocyte-related variables between placebo and risedronate. Risedronate significantly reduced bone-remodeling indices including mineralizing surface (MS/BS), bone formation rate (BFR/BS), and activation frequency (Ac.f). Risedronate treatment caused significantly lower MS/BS and Ac.f than placebo administration. In conclusion, risedronate 5 mg/day effectively inhibited bone remodeling but did not significantly reduce osteocyte viability in trabecular bone.

Practice and Attitudes towards CYP2D6 Testing for Patients on Tamoxifen among US Oncologists

Background: CYP2D6 genotype has been associated with breast cancer outcomes for patients on Tamoxifen (TAM) and testing is commercially available. In the context of emerging data regarding the clinical relevance of CYP2D6 testing (CYPT) and uncertainty regarding how test results should be used in practice, we evaluated current practice and attitudes with regard to this novel pharmacogenomic test among U.S. oncologists.Methods: A survey was mailed to all breast cancer oncologists identified at National Comprehensive Cancer Network (NCCNO) centers and a random sample of community based oncologists (CBO) identified from the American Society of Clinical Oncology directory. The survey evaluated knowledge of the CYP2D test, use of the test, requests for the test by patients and third parties, and response to hypothetical test results. Associations between practice setting and CYP2D6 knowledge, CYPT, and practice patterns were evaluated. All statistical tests were two-sided.Results: 201 of 459 (44%) oncologists responded, including 97/173 (56%) of NCCNO and 104/286 (36%) of CBO. While 90% of all oncologists were aware of CYPT, only 31% had ever ordered CYPT, and only 14% used CYPT for ≥ 10% of patients on TAM. 22% had received a request for CYPT from a 3rd party. While NCCNO were more likely to be aware of CYPT (98% vs. 82%, p < 0.001), and to receive requests for CYPT (33% vs. 12%, p < 0.001), CBO reported higher frequency of CYPT in routine practice (21% vs. 11%, p = 0.06). Despite rare use, 66% of CBO and 44% of NCCNO reported they would order the test upon patient request (p < 0.001). In hypothetical scenarios involving CYPT for patients on TAM, for premenopausal women with poor metabolism, 33% would make no change, while 38% would switch to ovarian suppression (OS) plus aromatase inhibitor (AI), 9% would switch to OS alone, and 8% would add OS to TAM. CBO were more likely to switch to OS + AI in this setting (47% vs. 31%, p < 0.02), while NCCNO were more likely to recommend no change (50% vs. 18%, p < 0.001). For premenopausal intermediate metabolizers, 33% of CBO would change management, compared to 8% of NCCN (p < 0.001), with addition of OS to TAM being most frequent among both groups. For postmenopausal women with poor metabolism the majority of both CBO and NCCNO would switch to AI (82% vs. 71%, p = 0.08). Among oncologists who indicated they might change management based on CYPT results, 43% had never ordered the test. Respondents cited data from randomized trials, and professional guidelines as most influential for decisions regarding ordering tests.Conclusion: Despite calls for increased CYP2D6 testing at academic meetings and occasional requests by 3rd parties, use of CYPT is currently infrequent in oncology practice. Greater familiarity with breast cancer management correlated with lower use of CYPT and greater reluctance to change management based on test results at this time. Diversity in practice patterns and knowledge suggests a need for greater consensus on CYPT in routine practice, and highlights the need for further clinical research in this area.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1077.

Immunogenicity of Ra1A and its tissue-specific expression in hepatocellular carcinoma

In order to understand the immunogenicity of a tumor-associated antigen (TAA), Ras family small GTP binding protein (Ra1A) in hepatocellular carcinoma (HCC), autoantibody responses to RalA were evaluated by enzyme-linked immunosorbent assay (ELISA), Western blotting and indirect immunofluorescence assay in sera from patients with HCC and sera from normal individuals. Immunohistochemistry (IHC) study with tissue array slides was also performed to analyze protein expression profiles of RalA in HCC and control tissues. This study demonstrated that RalA had a relative higher frequency of autoantibody response in HCC (20.1%) compared to liver cirrhosis (3.3%), chronic hepatitis (0%), and normal individuals sera (0%). RalA also showed a stepwise increased expression from normal liver tissues (26.7%), liver cirrhosis tissues (45.0%) to HCC tissues (63.3%). Sensitivity and specificity of anti-RalA antibody in detection of HCC was 20.1% and 99.3%, respectively. The data suggested that RalA might contribute to liver malignant transformation, and could be used as a potential tumor marker in HCC detection.

Exercise training improved insulin sensitivity and ovarian morphology in rats with polycystic ovary syndrome

Hyperandrogenism and hyperinsulinemia are major clinical features in women with polycystic ovary syndrome (PCOS). We hypothesized that serum insulin levels reduced by exercise could relieve hyperandrogenism and ameliorate polycystic ovarian morphology. Wistar female rats with 21-day-old were randomly divided into three groups: PCOS exercise (P-Ex), PCOS sedentary (P-Sed), and control sedentary (C-Sed). The rats with PCOS were induced by injection with testosterone propionate continuously. The exercise program was to swim with 120 min/d for two weeks. Fasting blood glucose (FBG) and insulin (FINS), estrogen (E (2)), progesterone (P), and testosterone (T) in serum were determined by RIA, and ovarian morphology was evaluated by Image-Pro Plus 6.0. The levels of FINS, E (2), and T in serum were significantly lower in P-Ex than in P-Sed. The ratios of FBG/FINS in P-Ex significantly increased in comparison with P-Sed. The levels of serum sex hormones in P-Ex were similar to C-Sed. There were no differences in blood glucose and serum progesterone among three groups. Ovarian morphology showed that the numbers of preantral follicles and atretic follicles significantly decreased, and the numbers of antral follicles and corpora lutea significantly increased in P-Ex compared with P-Sed. The changes of ovarian morphology in P-Ex were similar to C-Sed. These results demonstrated that short-term exercise training can improve insulin sensibility, decrease serum androgen levels, and recover normal ovarian morphology. The exercise training is the basic therapeutic means for PCOS.

Effect of (-)-gossypol (AT-101) on transcriptional regulation of Noxa and Puma and on Mcl-1-mediated cancer cell resistance to apoptosis

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Background: AT-101 is being evaluated in Phase II clinical trials for the treatment of human cancers and demonstrates anticancer activity as a single agent and in combination with docetaxel. Despite extensive investigations, the mechanism of action for its antitumor activity is not completely understood. In this study, we have performed detailed investigations using a panel of human cancer cell lines on the mechanism of action for AT-101. Methods: A series of human breast and prostate cancer cell lines were utilized to evaluate the antitumor activity of AT-101. Cell growth inhibition, cell viability and apoptosis were determined by WST assay, trypan blue assay and flow cytometry, respectively. Gene specific siRNAs were used to knockdown target gene expression. Quantitative RT- PCR was performed to detect the mRNA levels of Puma and Noxa. Co-immunoprecipitation was carried out to detect the association between Mcl-1 and Noxa or Puma. Results: AT-101 induced apoptosis in both Bax/Bak-dependent and -independent manners in a variety of human cancer cell lines concomitant with increased expression of Noxa and Puma in a p53-independent manner. The up-regulation of Noxa was not observed in normal primary breast epithelial cells or normal-like human breast epithelial MCF-12F cells. Transcription inhibitor actinomycin D blocked AT-101-induced up-regulation of Puma and Noxa. Knockdown of Noxa or Puma attenuated AT-101-induced apoptosis. Furthermore, AT-101 effectively overcame Mcl-1-mediated cancer cell resistance to apoptosis. Co-immunoprecipitation studies demonstrated that Mcl-1 specifically associated with Noxa but not Puma. Conclusions: Our findings suggest that transcriptional up-regulation of pro-apoptotic Noxa and Puma contributes to the antitumor activity of AT-101, which plays a dominant role in antagonizing Mcl-1 and overcoming Mcl-1-mediated resistance to apoptosis of cancer cells. AT-101 functions as an antagonist of Bcl-2, Bcl-xL and Mcl-1 through direct binding to these proteins, as well as through upregulation of Noxa and Puma.

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High expression levels of putative hepatic stem/progenitor cells biomarkers related to tumor angiogenesis and poor prognosis of hepatocellular carcinoma

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Background: To investigate the prognostic values of putative hepatic stem/progenitor cells (HSCs/HPCs) biomarkers in hepatocellular carcinoma (HCC) patients. Methods: Fourteen biomarkers related with HSCs/HPCs or tumor angiogenesis were assessed by qRT-PCR and then validated by tissue microarrays (TMAs) in three independent cohorts of HCC patients underwent curative resection (n=67, 314 and 73). Results: Most of the biomarkers were found over-expressed in recurrent HCC patients by qRT-PCR. HSCs/HPCs biomarkers cytokeratin 19, ABCG2, CD133, Nestin, CD44 and angiogenesis agents CD34, VEGF and PD-ECGF, were confirmed as significant predictors for overall survival (OS) and/or relapse-free survival (RFS) in TMAs analysis. Compared with the low HSCs/HPCs profile group, patients with high HSCs/HPCs profile had significantly lower OS and RFS (p<0.0001), expressed higher VEGF levels (p = 0.012) and microvessel density (MVD, determined by CD34 immunostaining, p = 0.030). Based on Cox regression, a simplified model including CD133, CD44, Nestin, and MVD was constructed and confirmed as an independent predictor for OS (p<0.0001) and RFS (p<0.0001), regardless of alpha-fetoprotein level, tumor stage and recurrence time (p<0.0001 for all). Conclusions: High expression levels of HSCs/HPCs biomarkers are related to tumor angiogenesis and poor prognosis of HCC. The simplified model based on HSCs/HPCs and tumor angiogenesis profile can be used to classify HCC patients with high risk of tumor recurrence after operation.

No significant financial relationships to disclose.

Expression of CD24 as a predictor of prognosis of hepatocellular carcinoma after operation

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Background: CD24 expression has previously been reported in hepatocellular carcinoma (HCC), although little is known about its prognostic significance. The aim of this study is to evaluate the relation of CD24 expression and its prognostic significance in HCC. Methods: CD24 expression in stepwise metastatic HCC cell lines and tumor tissues from 50 HCC patients was investigated by quantitative real-time reverse transcription-PCR and Western blot analyses. The role of CD24 was investigated by depletion CD24 expression in HCC cells through small-interfering RNA. Tumor tissue microarrays of 314 HCC patients who underwent resection between 1997 and 2000 were used to detect the expressions of CD24, β-catenin and PCNA expression. The prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests. Results: CD24 was overexpressed in the high metastatic HCC cell line and in tumor tissues of recurrent patients. Depletion of CD24 caused a notable decrease in cell proliferation, migration and invasiveness in vitro. CD24 was confirmed as an independent predictor for overall survival (p<0.001) and relapse-free survival (p<0.001), regardless of recurrence time, AFP level, TNM stage and Edmondson stage. High expression of CD24 in HCC tissues was significantly associated cytoplasmic/nuclear accumulation of β-catenin (p=0.023), high tumor proliferate status (p=0.018) and diffused intrahepatic recurrence and distance metastasis (p=0.026). Adjuvant TACE after operation reduced the early recurrence (≤1 year) in CD24+ HCC patients (p=0.024), while there had no significant changes in CD24- patients (p=0.284). Conclusions: High expression levels of CD24 were related with high invasive and metastatic potential, high tumor proliferation status and activation of Wnt/β-catenin pathway. The expression of CD24 provides new prognostic information about HCC prognosis and targeted therapy to CD24+fraction in HCC may comprise a promising anti-recurrence strategy for HCC patients after surgery.

No significant financial relationships to disclose.

Magnetic resonance imaging of primary cerebral gliosarcoma: a report of 15 cases

BACKGROUND

Gliosarcomas are rare tumors with mixed glial and mesenchymal components. Many of their radiologic features resemble those of other primary brain malignancies.

PURPOSE

To investigate the magnetic resonance (MR) imaging features of gliosarcomas.

MATERIAL AND METHODS

We retrospectively reviewed the MR images, pathology reports, and clinical information of 11 male and four female patients aged 15-71 years to evaluate the location, morphology, enhancement, and other features of their pathologically confirmed gliosarcomas.

RESULTS

Apart from one tumor in the right cerebellar hemisphere, all were supratentorial. Two tumors were intraventricular, and four involved the corpus callosum. The tumors were well demarcated, with an inhomogeneous or cystic appearance and moderate-to-extensive surrounding edema. Thick walls with strong rim and ring-like enhancement were observed in 13 (87%). Seven (47%) showed intratumoral paliform enhancement.

CONCLUSION

Gliosarcoma demonstrates certain characteristic MR features, such as supratentorial and peripheral location, well-demarcated, abutting a dural surface, uneven and thick-walled rim-like or ring enhancement, as well as intratumoral strip enhancement. These findings, combined with patient age, can aid the differential diagnosis of gliosarcomas from more common primary brain tumors.

First intercomparison of Tn-Rn discriminative measurements in China

The intercomparison measurements with Tn-Rn discriminative monitor were conducted at the Radon Laboratory of Nanhua University. The intercomparison results indicates that the Tn-Rn discrimination of most monitors (including the solid-state nuclear track detector of participant A and participant B, continuous monitors of RAD7 and RTM2100) keeps well in a wide range of the ratio of Tn to Rn. There are great differences of Tn measurement results among RAD7, RTM2100 and reference instrument. The discussion on the reason of these differences reveals the necessity of improvement on monitor calibration, Tn source make and the necessity of more international intercomparisons.

Calibration of a 220Rn flow-through source

Two reference methods have been established to calibrate the yield of a self-made 220Rn flow-through source. These reference methods include (a) a small scintillation cell flow-through method and (b) a gamma spectrometry method that takes advantage of an activated charcoal. The methods were validated theoretically and experimentally including intercomparison measurements. It is shown that the source is stable with a relative deviation less than 2.5% over 5 years, when the relative humidity ranged from 50 to 90%, and the temperature from 5 to 38 degrees C. The 220Rn monitor used in these reference methods is calibrated without a 220Rn gas source with determinate yield. On the basis of the calibration of the 220Rn source by the methods mentioned above, the accurate calibration of any 220Rn monitor by the self-made 220Rn source with stable yield is feasible.

Relationships between osteocyte density and bone formation rate in human cancellous bone

Iliac cancellous osteocyte density decreases with age in deep bone but not in superficial bone, most likely because of remodeling. It has been suggested that osteocytes can inhibit bone remodeling. Accordingly, we examined the relationship between osteocyte density and bone formation rate in 92 healthy women. In superficial bone (<25 microm from the surface), we found a weak but significant (p < 0.03) inverse correlation between BFR/BS and Ot. N/B.Ar that was unaffected by menopause and independent of age. A weaker positive relationship with empty lacunar density improved significance. The data appear to suggest a negative feedback loop, but osteocytes explain only 10% of the variance in BFR/BS, and 97% of the variance in osteocyte density is explained by total lacunar density. This measure of initial osteocyte density during bone formation has a high coefficient of variation (20%) indicating large individual differences. We conclude that: (1) our data support the proposal that osteocytes can inhibit bone remodeling; (2) osteocyte density in superficial bone depends mainly on initial osteocyte density during bone formation and is maintained but not regulated by bone remodeling; and (3) the inverse relationship between BFR/BS and osteocyte density may reflect the homeostatic need to maintain calcium exchangeability in the lining cell-osteocyte syncytium.

Age and distance from the surface but not menopause reduce osteocyte density in human cancellous bone

Previous studies of osteocyte density in human cancellous bone have relied mainly on autopsy samples and have demonstrated an age-related decline in men, but there are insufficient data in women. Using previously obtained transiliac bone biopsies from 94 healthy white women, aged 20-73 years, 38 premenopausal and 56 postmenopausal, we measured osteocytes and lacunae in ten randomly selected areas using 5-microm-thick sections stained with Goldner trichrome. For each subject, the number of osteocytes (Ot.N/B.Ar), empty lacunae (EL.N/B.Ar), and total lacunae (Tt.L.N/B.Ar) per bone area, and the proportion of occupied lacunae (Ot.N/Tt.L.N), were calculated. In 92 cases the measurements were made separately in superficial bone (<25 microm from the surface) and in deep bone (>45 microm from the surface). Mean values and differences between extreme values (DEV) for each variable were computed from the ten measured areas. In addition, confocal microscopic examination was performed on 100 microm sections. We found that Ot.N/B.Ar, Tt.L.N/B.Ar, and Ot.N/Tt.L.N decreased, but EL.N/B.Ar increased significantly with age (p < 0.001). The rates of decline were most rapid initially, falling exponentially with increasing age; the linear regressions for all four variables were significant in premenopausal, but not postmenopausal, women. At all ages, there were significantly more osteocytes in superficial than in deep bone; there was no significant decline with age in superficial bone, but a steeper exponential decline in deep bone than in whole trabeculae. DEV did not change with age for any variable. Confocal images revealed that the morphology of the osteocyte network was heterogeneous in different regions and trabeculae. The trabeculae with lower osteocyte density contained acellular areas, especially in interstitial bone. We conclude: (1) osteocyte density declines with age in women as it does in men; (2) the decline occurs exclusively in deep bone, not in superficial bone, suggesting that it is the age of the bone rather than the age of the subject that is important; (3) the rate of age-related decline falls exponentially with age and is not significant in postmenopausal women alone; (4) except for the differences between superficial and deep bone, the pattern of osteocyte distribution within and between trabeculae was not affected by age or menopause; and (5) the data raise the possibility that one function of remodeling in iliac cancellous bone is to maintain osteocyte viability.

The crystal structure of the influenza matrix protein M1 at neutral pH: M1-M1 protein interfaces can rotate in the oligomeric structures of M1

The influenza matrix protein (M1) forms a protein layer under the viral membrane and is essential for viral stability and integrity. M1 mediates the encapsidation of the viral RNPs into the viral membrane by its membrane and RNP-binding activities. In order to understand the roles of M1-M1 protein interactions in forming the M1 layer, X-ray crystallographic studies of a M1 fragment (1-162) were carried out at neutral pH and compared with an acidic pH structure. At neutral pH the asymmetric unit was a stacked dimer of M1. A long molecular ribbon of neutral stacked dimers was formed by translation as dictated by the P1 space group. The elongated ribbon had a positively charged stripe on one side of the ribbon. A similar M1-M1 stacking interface was also found in the acidic asymmetric unit. However, within the acidic stacked dimer the molecules were not straight, but rotated in relation to each other by slightly changing the M1-M1 stacking interface. The acidic structure possessed an additional M1-M1 twofold interface. Protein docking confirmed that the M1-M1 stacking and M1-M1 twofold interfaces could be used to form a double ribbon of M1 molecules. By iterative repetition of the rotated relationship among the M1 molecules, a helix of M1 was generated. These studies suggest that M1 has the ability to form straight or bent elongated ribbons and helices. These oligomers are consistent with previous electron microscopic studies of M1, which demonstrated that isolated M1 formed elongated and flexible ribbons when isolated from what appeared to be a helical shell of M1 in the influenza virus.

Preferential production of interferon-gamma by CD4+ T cells expressing the homing receptor integrin alpha4/beta7

Recent studies indicate that T helper type 1 (Th1) and 2 (Th2) lymphocytes differ in their expression of molecules that control T-cell migration, including adhesion molecules and chemokine receptors. We investigated the relationship between cytokine production and expression of the homing receptor integrin alpha4/beta7 on T cells. We began by analysing cytokine production by human CD4+ CD45RA- memory/effector T cells following brief (4 hr) stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin. alpha4/ beta7high CD4+ T cells were more likely to produce the Th1 cytokine interferon-gamma (IFN-gamma) than were alpha4/beta7- CD4+ T cells in all six subjects studied. In contrast, production of the Th2 cytokine interleukin-4 (IL-4) was similar on alpha4/ beta7high and alpha4/beta7- CD4+ T cells. In addition, we found that human CD4+ CD45RA- T cells that adhered to the alpha4/beta7 ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1) had a greater capacity to produce IFN-gamma than did non-adherent cells, suggesting that the association between alpha4/beta7 expression and IFN-gamma production has functional significance. These results suggested that primary activation under Th1-promoting conditions might favour expression of alpha4/beta7. We directly examined this possibility, and found that naïve murine CD4+ T cells activated under Th1-promoting conditions expressed higher levels of alpha4/beta7 compared to cells activated under Th2-promoting conditions. The association between alpha4/beta7 expression and IFN-gamma production by CD4+ T cells may help to determine the cytokine balance when MAdCAM-1 is expressed at sites of inflammation in the intestine or elsewhere.