Preservation of islet survival by upregulating α3 integrin signaling: the importance of 3-dimensional islet culture in basement membrane extract

AIM

Islet transplantation is a promising treatment to cure diabetes, but is associated with a high rate of early graft failure. The isolation process leads to the loss of the surrounding extracellular matrix, resulting in eventual islet disintegration and apoptosis. The purpose of this study was to determine the effects on the viability of isolated islets of embedding islets in reconstituted basement membrane extract (BME), which is similar to the normal peri-islet BM composition in vivo.

METHODS

Isolated mouse islets were embedded in BME gel for 24 or 48 hours. Expression of caspase-3, α3, and α5, focal adhesion kinase (FAK), phosphor-FAK, and pancreatic duodenal homeobox factor (PDX)-1 were detected with Western immunoblotting.

RESULTS

Impaired aggregation of single islet cells could only be observed in non-BME medium. Islets embedded in BME gel were partially protected from anoikis showed decreased caspase-3 compared with non-BME islets. We also observed an increase of α3 integrin, FAK protein level, and FAK activity. Furthermore, expression of PDX-1 was preserved at 48 hours, suggesting a positive contribution of BME to β-cell activity.

CONCLUSION

These results indicated that embedding islets in BME can upregulate α3 integrin, which may result in preservation of viability and function of isolated islets.

EGFR, TS, and ERCC1 expression in penile squamous cancer (PSC)

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Background: PSC is an aggressive disease with devastating consequences. While near-universal EGFR overexpression has been documented, little is known about its clinical implications, and the potential role of KRAS mutations has not been described. In other tumor types, ERCC1 and TS expression are associated with response to platinum and 5FU chemotherapy, but have not yet been evaluated in PSC.

Methods: After IRB approval, 28 PSC patients treated at LAC-USC were identified with tumor specimens available. Testing for EGFR, TS, and ERCC1 expression relative to internal standard gene was performed by real-time RT-PCR and correlated with clinical features.

Results: The median age was 45 (30-78). There were 2 Black, 1 Asian, 1 White, and 15 Hispanic men; 9 had unspecified race. T stages included 4 Tis, 6 T1, 17 T2, and 9 T3; 11 men had lymph node (LN) involvement. No KRAS mutations were identified. EGFR had the highest relative expression (median 4.65, range 1.6-44.2), followed by TS (median 1.69, range 0.49-4.69); ERCC1 overexpression was rare (median 0.54, range 0.21-1.29). Higher EGFR expression was significantly associated with poor differentiation (median 12.5 compared to 3.6 for moderate/well differentiated tumors) on continuous (p=0.03 by Mann Whitney) and cut-point analysis using >7 (two- sided p=0.03 by Fisher's exact test) but did not correlate with stage. Stage > T2 showed a trend toward higher risk of LN involvement (p=0.06 by chi square). There was no correlation between differentiation and stage, and no significant correlation for ERCC1 or TS with grade or stage.

Conclusions: EGFR overexpression is common in PSC and correlates with tumor grade but not stage, suggesting it may be important for disease progression. The absence of KRAS mutations may portend responsiveness to EGFR- targeted therapy based on experience in other tumors. Low ERCC1 as an association with platinum response will be explored in an expanded cohort.

No significant financial relationships to disclose.

Microwave Sintering of Zirconia Toughened Mullite (ZTM)

Microwave sintering of zirconia toughened mullite (ZTM) has been performed in a single mode applicator. In comparison with conventional sintering, microwave processing of ZTM leads to a higher density and finer grain size. Microstructure of microwave sintered ZTM was characterized by TEM and HRTEM techniques. The pinning of intergranular ZrO2 dispersoids retarded the grain growth of mullite matrix. The observation of a considerable number of trans-granular microcracks indicates that microcracking toughening is the main toughening mechanism for ZTM.

The protective effect of Bdellovibrio-and-like organisms (BALO) on tilapia fish fillets against Salmonella enterica ssp. enterica serovar Typhimurium

AIMS

To characterize freshwater Bdellovibrio-and-like organisms (BALO) isolated in China and examine their potential in controlling growth of Salmonella enterica ssp. enterica serovar Typhimurium on tilapia fillets.

METHODS AND RESULTS

Four BALO isolates were recovered from a pond in Yanzhou of Shandong province, China, with Salm. Typhimurium as prey using double-layer agar method. Partial 16S rDNA sequencing analysis identified BD2GL, BD5GL and BDXGL as Bdellovibrio bacteriovorus and BD2GS as a Peredibacter sp. Lysis experiments on 32 potentially pathogenic strains revealed that BALO lysis rates are in the range of 56.3-65.6%. On the five Salmonella strains tested, only BD2GS achieved 100% lysis rate. When applied on tilapia fillets against Salm. Typhimurium, BD2GS showed its growth control potential. Cell increments of Salm. Typhimurium were significantly lower (P < 0.05) in two BD2GS-treated groups compared to control and low-dose group (BD2GS to prey ratio, 1 : 1) was more effective than high-dose group (BD2GS to prey ratio, 10 : 1) in controlling Salm. Typhimurium growth.

CONCLUSIONS

Results of this study indicated that BD2GS could control Salm. Typhimurium growth on tilapia fillets.

SIGNIFICANCE AND IMPACT OF THE STUDY

BALO could be used as a live protective culture in controlling bacterial growth and ensure food safety.

A noninvasive imaging approach to assess plaque severity: the carotid atherosclerosis score

BACKGROUND AND PURPOSE

The presence of IPH and/or FCR in the carotid atherosclerotic plaque indicates a high-risk lesion. The aim of this multicenter cross-sectional study was to establish the characteristics of lesions that may precede IPH and/or FCR. We further sought to construct a CAS that stratifies carotid disease severity.

MATERIALS AND METHODS

Three hundred forty-four individuals from 4 imaging centers with 16%-99% carotid stenosis by duplex sonography underwent carotid MR imaging. In approximately 60% of the study sample (training group), multivariate analysis was used to determine factors associated with IPH and FCR. Statistically significant parameters identified during multivariate analysis were used to construct CAS. CAS was then applied to the remaining arteries (40%, test group), and the accuracy of classification for determining the presence versus absence of IPH or, separately, FCR was determined by ROC analysis and calculation of the AUC.

RESULTS

The maximum proportion of the arterial wall occupied by the LRNC was the strongest predictor of IPH (P < .001) and FCR (P < .001) during multivariate analysis of the training group. The subsequently derived CAS applied to the test group was an accurate classifier of IPH (AUC = 0.91) and FCR (AUC = 0.93). Compared with MRA stenosis, CAS was a stronger classifier of both IPH and FCR.

CONCLUSIONS

LRNC quantification may be an effective complementary strategy to stenosis for classifying carotid atherosclerotic disease severity. CAS forms the foundation for a simple imaging-based risk-stratification system in the carotid artery to classify severity of atherosclerotic disease.

The clinicopathological significance of BUBR1 overexpression in hepatocellular carcinoma

BACKGROUND AND AIMS

BUBR1 is a key component of the mitotic spindle checkpoint, and its roles in human cancers are controversial and unclear. The aim of this study was to investigate the clinicopathological significance of BUBR1 expression in hepatocellular carcinoma (HCC).

METHODS

The BUBR1 protein and its mRNA levels were measured in 58 HCCs, nine high-grade dysplastic nodules and their paired non-tumorous liver tissues by quantitative real-time polymerase chain reaction (qPCR) and western blot, respectively. In addition, immunochemical analysis of the BUBR1 protein was performed in 458 HCCs and 46 dysplastic nodules, and the clinicopathological significance of the BUBR1 expression was evaluated.

RESULTS

The BUBR1 expression at both mRNA and protein levels was elevated in two of nine high-grade dysplastic nodules and in 37 of 58 (64%) HCCs. BUBR1 was overexpressed in 207 of 458 (45%) HCCs by immunohistochemistry. Intriguingly, high expression of the BUBR1 was correlated with larger tumour size, higher histological grade, advanced pathological stage, and poor overall and recurrence-free survival. There was a higher frequency of BUBR1 overexpression in cases with positive serum HBsAg than those with negative HBsAg. Moreover, BUBR1 overexpression was associated with P53 staining and high Ki67 labelling indices in HCC tissues.

CONCLUSIONS

BUBR1 was overexpressed in about 45% HCCs, and its overexpression may be a relative lately event in HCC progression. Overexpression of BUBR1 was associated with worse prognosis and is a potential prognostic factor for patients with HCC.

Marginal hazards model for case-cohort studies with multiple disease outcomes

Case-cohort study designs are widely used to reduce the cost of large cohort studies while achieving the same goals, especially when the disease rate is low. A key advantage of the case-cohort study design is its capacity to use the same subcohort for several diseases or for several subtypes of disease. In order to compare the effect of a risk factor on different types of diseases, times to different events need to be modelled simultaneously. Valid statistical methods that take the correlations among the outcomes from the same subject into account need to be developed. To this end, we consider marginal proportional hazards regression models for case-cohort studies with multiple disease outcomes. We also consider generalized case-cohort designs that do not require sampling all the cases, which is more realistic for multiple disease outcomes. We propose an estimating equation approach for parameter estimation with two different types of weights. Consistency and asymptotic normality of the proposed estimators are established. Large sample approximation works well in small samples in simulation studies. The proposed methods are applied to the Busselton Health Study.

Characterization of a major colon cancer susceptibility locus (Ccs3) on mouse chromosome 3

Treatment of mice with the carcinogen azoxymethane (AOM) induces a number of lesions in the colon, including hyperplastic lesions, as well adenomas and carcinomas in situ. Inbred strains of mice show different responses to AOM-induced carcinogenesis. A/J mice are highly susceptible and develop a greater number of hyperplastic lesions and tumors (15-70 tumors per mouse) than resistant C57BL/6J mice (0-6 tumors per mouse). Susceptibility to AOM-induced tumors segregates as a co-dominant trait in (A x B6)F1 hybrids. Using a set of 23 AcB and BcA recombinant congenic mouse strains derived from A/J (susceptible) and B6 (resistant) parents, we observed that the number of hyperplastic lesions and tumors induced by AOM was under different genetic controls in AcB/BcA strains. The multiplicity of AOM-induced tumors is controlled by a major locus that we have mapped on the distal portion of chromosome 3, to which we have given the temporary designation colon cancer susceptibility locus 3 (Ccs3). B6 and A/J alleles at Ccs3 are associated with resistance and susceptibility, respectively. Haplotype analysis in key informative AcB/BcA strains restricts the size of the Ccs3 locus to a 14 Mb segment that contains 94 annotated genes. The expression level of all these genes in normal colon has been established by transcript profiling with microarrays, and has led to the identification of a subset of positional candidates that are expressed at high levels in this tissue. The 4q and 1p human chromosomal segments sharing syntenic homology with the mouse Ccs3 segment are known to be associated with inflammatory bowel diseases and colorectal tumors in humans, suggesting that the study of the mouse Ccs3 locus may help further the pathogenesis of these human conditions.