[Correlation between Toxoplasma gondii infection and spontaneous abortion in pregnant women: a case-control study]

OBJECTIVE

To examine the correlation between Toxoplasma gondii infection and spontaneous abortion among pregnant women, so as to provide the evidence for the developmentofpreventivemeasuresforspontaneousabortion.

METHODS

A total of 228 serum samples collected from women with spontaneous abortion for the first time from January 2018 to December 2019 were selected as the case group, while 228 serum samples collected from pregnant women with a normal delivery and without a history of abortion during the same period were selected as the control group. The serum IgG and IgM antibodies against T. gondii were detected and compared in both groups, and the correlation between T. gondii infection and spontaneous abortion was evaluated.

RESULTS

There were no significant differences between the case and control groups in terms of age, education levels, occupation, residency and proportion of keeping cats (all P values > 0.05). The positive rate of anti-T. gondii IgM antibody was significantly higher in the case group than in the control group (adjusted χ² = 4.08, P < 0.05; OR = 8.25), while no significant difference was seen between the case and control groups (χ² = 0.42, P > 0.05).

CONCLUSIONS

Acute maternal T. gondii infection may remarkably increase the chance of spontaneous abortion. Progestational health education regarding toxoplasmosis prevention and control knowledge and detection of T. gondii infection during pregnancy should be strengthened.

[Expression and significance of PD-1 and PD-L1 in the specimens of epithelial ovarian cancer]

Objective: To examine the expression of programmed cell death 1 (PD-1) and its ligand (PD-L1) in epithelial ovarian cancer (EOC) tissues, and investigate the correlation among their expression, clinicopathological features and prognosis. Methods: The specimens of 180 patients with EOC treated in the First Affiliated Hospital of Dalian Medical University from October 2002 to December 2013 were confirmed by pathological examination. The pathological tissue specimens of subtypes ，included 120 cases of serous carcinoma, 30 cases of mucinous carcinoma, 20 cases of endometrioid carcinoma, and 20 cases of clear cell carcinoma. The normal paracancerous tissues of 50 cases randomly selected from the 180 patients as control group. Immunohistochemical SP method was used to detect the expressions of both PD-1 and PD-L1 in epithelial ovarian cancer tissues, and the relationships among their expressions,the clinicopathological parameters and prognosis were respectively analyzed. Results: （1） PD-1 was expressed in lymphocytes infiltrated in EOC tissues, and PD-L1 was expressed in the cell membranes of cancer tissues. In all EOC cases, 33 cases (18.3%, 33/180) of both PD-1 and PD-L1 were highly expressed, and only 1 (2.0%, 1/50) of control group showed high expression. There was statistically significant difference between two groups (P<0.01). (2) Among the four subtypes tissue specimens of EOC, the high expression rate of PD-1 was 25.0% (30/120) for serous carcinoma, 3/15 for endometrioid carcinoma, 0 (0/30) for mucinous carcinoma, and 0 (0/15) for clear cell carcinoma. The high expression rate of PD-L1 was 23.3% (28/120) for serous carcinoma, 3.3% (1/30) for mucinous carcinoma, 2/15 for endometrioid carcinoma, and 2/15 for clear cell carcinoma. Both PD-1 and PD-L1 expressions in the four sub-types of tissue specimens were significantly different (P<0.05). The high expression rate of both PD-1 and PD-L1 was 9.2% (8/87) in the early stage and 26.9% (25/93) in the late stage. There was a statistically significant difference between the two groups (P<0.01). Similarly, the expression of both PD-1 and PD-L1 were significantly higher in the cases of high-grade EOC （type Ⅱ） than those of low-grade （type Ⅰ） and in the cases of EOC distributed bilaterally than that distributed unilaterally, and there were statistically significant differences (P<0.05). (3) The Kaplan-Meier survival analysis showed that the survival time were respectively 35 and 36 months in the cases with high expressions of both PD-1 and PD-L1, and the survival time were the same as 61 months in the cases with low expression of both PD-1 and PD-L1, and the comparison was statistically significant (P<0.05). Conclusions: The expression levels of PD-1 and PD-L1 in EOC tissues are higher than those in adjacent tissues, especially in serous carcinomas. The expression of both PD-1 and PD-L1 is higher in specimens of the patients with advanced stages. The results showed that the high expression of both PD-1 and PD-L1 is an indicator of poor prognosis of patients suffering from EOC.

Impacts of extreme summers on European ecosystems: a comparative analysis of 2003, 2010 and 2018

In Europe, three widespread extreme summer drought and heat (DH) events have occurred in 2003, 2010 and 2018. These events were comparable in magnitude but varied in their geographical distribution and biomes affected. In this study, we perform a comparative analysis of the impact of the DH events on ecosystem CO₂ fluxes over Europe based on an ensemble of 11 dynamic global vegetation models (DGVMs), and the observation-based FLUXCOM product. We find that all DH events were associated with decreases in net ecosystem productivity (NEP), but the gross summer flux anomalies differ between DGVMs and FLUXCOM. At the annual scale, FLUXCOM and DGVMs indicate close to neutral or above-average land CO₂ uptake in DH2003 and DH2018, due to increased productivity in spring and reduced respiration in autumn and winter compensating for less photosynthetic uptake in summer. Most DGVMs estimate lower gross primary production (GPP) sensitivity to soil moisture during extreme summers than FLUXCOM. Finally, we show that the different impacts of the DH events at continental-scale GPP are in part related to differences in vegetation composition of the regions affected and to regional compensating or offsetting effects from climate anomalies beyond the DH centres. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.

Dielectric approximation media to reproduce dispersion for field transformation

Field transformation is complementary to transformation optics as it converts polarization without reflection for any incidence, despite not being impedance-matched to vacuum. However, to ease manufacture, a dielectric approximation may degrade the transmission performance due to the approximate dispersion relation for the exact reciprocal medium. In this paper, we instead propose a different dielectric equivalent medium to guarantee the exact dispersion. We also discuss the birefringence phenomenon in such dielectric media, and their unavoidable induced reflections.

SAT0139 AGE-BASED (<65 VS ≥65 YEARS) INCIDENCE OF INFECTIONS AND SERIOUS INFECTIONS IN TOFACITINIB-, ADALIMUMAB- AND PLACEBO-TREATED PATIENTS WITH RHEUMATOID ARTHRITIS: A POST HOC ANALYSIS OF PHASE 2, PHASE 3 AND PHASE 3B/4 TOFACITINIB STUDIES

Background:

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). A recent ad hoc safety analysis (as of August 2019; may be subject to change) from an ongoing, open-label, randomised, post-authorisation safety study, Study A3921133 (NCT02092467), conducted in RA patients (pts) aged ≥50 years with ≥1 cardiovascular risk factor has shown that incidence rates (IRs) of serious infection events (SIEs) were higher with tofacitinib 10 mg BID vs tumour necrosis factor inhibitors (TNFi; adalimumab [ADA] and etanercept) and this difference was more pronounced in pts aged ≥65 years (Pfizer Inc; data on file).

Objectives:

To assess the IRs of overall infection events and SIEs in pts from Phase (P)2, P3 and P3b/4 tofacitinib RA trials which had a TNFi (ADA) active control or comparator arm.

Methods:

This is a post hoc analysis of Month 0–12 data pooled from P2 (A3921035;NCT00550446[first 12-week randomised parallel treatment period only]), P3 (ORAL Standard;NCT00853385) and P3b/4 (ORAL Strategy;NCT02187055) studies. Pts randomised to receive tofacitinib 5 mg BID, tofacitinib 10 mg BID, ADA 40 mg subcutaneously every other week and placebo (PBO) were included and assessed overall and by age (<65 or ≥65 years). SIEs were defined as infections requiring hospitalisation or parenteral antimicrobial therapy, or meeting other criteria for a serious adverse event. IRs (pts with events/100 pt-years of exposure [PY]) and 95% confidence intervals (CIs) were calculated for all infection events and SIEs; only the first infection events that occurred up to 28 days after the last dose or to the data cut-off date were considered.

Results:

Of 2180 pts included in the pooled studies (tofacitinib 5 mg BID: N=1064 [943.4 PY]; tofacitinib 10 mg BID: N=306 [236.6 PY]; ADA: N=643 [554.3 PY]; PBO: N=167 [108.1 PY]), 1841 (84.4%) were aged <65 years and 339 (15.6%) were aged ≥65 years. In general, the IRs for all infection events and SIEs were higher with tofacitinib 5 mg BID, tofacitinib 10 mg BID and ADA in pts aged ≥65 years compared with pts aged <65 years. Overall and when stratified by age, IRs for all infection events were similar across the active treatment groups (Figure 1); IRs with PBO were lower vs the active treatment groups overall and in pts aged <65 years, and numerically lower vs the active treatment groups in pts aged ≥65 years. IRs for SIEs were comparable across active treatment groups in pts aged <65 years, while among pts aged ≥65 years, IRs were numerically higher for tofacitinib 10 mg BID vs ADA, and appeared to be similar for tofacitinib 5 mg BID and ADA (Figure 2).

Conclusion:

In this analysis of data pooled from P2, P3 and P3b/4 tofacitinib RA studies which included a TNFi arm (ADA), the risk of SIEs or infections overall was similar for tofacitinib and ADA with the exception of a numerically higher rate of SIEs with tofacitinib 10 mg BID vs ADA in pts aged ≥65 years. In most countries, tofacitinib 10 mg BID is not an approved dose for the treatment of RA. This post hoc comparison is limited by variation in sample size and PY of exposure between treatment and age groups, and a small number of cases of SIEs in the ≥65-year age group resulting in wide 95% CIs; interpretation of results should be made with caution. The findings in the present analysis are consistent with increasing age being a known risk factor for infections.

Acknowledgments:

Study sponsored by Pfizer Inc. Medical writing support was provided by Christina Viegelmann of CMC Connect and funded by Pfizer Inc.

Disclosure of Interests: :

Kevin Winthrop Grant/research support from: Bristol-Myers Squibb, Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Galapagos, Gilead, GSK, Pfizer Inc, Roche, UCB, David Gold Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, Dan Henrohn Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, Lisy Wang Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, Andrea Shapiro Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, Harry Shi Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, Gustavo Citera Grant/research support from: AbbVie, Amgen, Eli Lilly, Gema, Genzyme, Novartis and Pfizer Inc, Consultant of: AbbVie, Amgen, Eli Lilly, Gema, Genzyme, Novartis and Pfizer Inc, Hendrik Schulze-Koops Grant/research support from: Pfizer Inc

Rapid preparation of decellularized trachea as a 3D scaffold for organ engineering

OBJECTIVE

To shorten the preparation time of rabbit decellularized tracheal matrix through a modified detergent-enzymatic method with higher concentration of DNase (50 kU/mL), providing an experimental and theoretical basis for clinical decellularization technology.

METHODS

The control group was a natural trachea, and the experimental group was a tracheal matrix subjected to two and four decellularization cycles. The performance of each group of samples was evaluated by histology and immunohistochemical staining, scanning electron microscopy, biomechanical property testing, inoculation and cytotoxicity tests, and allograft experiments.

RESULTS

The results showed that the nuclei of the nonchondral areas of the tracheal stroma were essentially completely removed and MHC-I and MHC-II antigens were removed after two decellularization cycles. Histological staining and scanning electron microscopy showed that the extracellular matrix was retained and the basement membrane was intact. Cell inoculation and proliferation tests confirmed that the acellular tracheal matrix had good biocompatibility, and the proliferation capacity of bone mesenchymal stem cells on the matrix was increased in the experimental group compared with the control group (p < 0.05). Histological staining and CD68 molecular marker analysis after the allograft experiment showed that the inflammatory response of the acellular tracheal matrix was weak and the infiltration of surrounding macrophages was reduced.

CONCLUSION

A modified detergent-enzymatic method with an increased DNase (50 kU/mL) concentration requires only two cycles (4 days) to obtain a decellularized rabbit tracheal matrix with a short preparation time, good biocompatibility, suitable mechanical properties, and reduced preparation cost.

Multiple-centre clinical evaluation of an ultrafast single-tube assay for SARS-CoV-2 RNA

OBJECTIVE

To evaluate the performance of an ultrafast single-tube nucleic acid isothermal amplification detection assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA using clinical samples from multiple centres.

METHODS

A reverse transcription recombinase-aided amplification (RT-RAA) assay for SARS-CoV-2 was conducted within 15 minutes at 39°C with portable instruments after addition of extracted RNA. The clinical performance of RT-RAA assay was evaluated using 947 clinical samples from five institutions in four regions of China; approved commercial fluorescence quantitative real-time PCR (qRT-PCR) kits were used for parallel detection. The sensitivity and specificity of RT-RAA were compared and analysed.

RESULTS

The RT-RAA test results of 926 samples were consistent with those of qRT-PCR (330 were positive, 596 negative); 21 results were inconsistent. The sensitivity and specificity of RT-RAA was 97.63% (330/338, 95% confidence interval (CI) 95.21 to 98.90) and 97.87% (596/609, 95% CI 96.28 to 98.81) respectively. The positive and negative predictive values were 96.21% (330/343, 95% CI 93.45 to 97.88) and 98.68% (596/604, 95% CI 97.30 to 99.38) respectively. The total coincidence rate was 97.78% (926/947, 95% CI 96.80 to 98.70), and the kappa was 0.952 (p < 0.05).

CONCLUSIONS

With comparable sensitivity and specificity to the commercial qRT-PCR kits, RT-RAA assay for SARS-CoV-2 exhibited the distinctive advantages of simplicity and rapidity in terms of operation and turnaround time.

Muscle from grass- and grain-fed cattle differs energetically

Insufficient acidification results in dark, firm, and dry beef. While this defect is often indicative of a stress event antemortem, muscle tissue may change in response to feeding regime. Longissimus dorsi muscle samples from 10 grain-fed and 10 grass-fed market weight, angus-crossbred beef cattle were collected postmortem. Lower (P < .05) L* and a* values were recorded for steaks from grass-fed cattle. Higher (P < .05) ultimate pH values were noted in lean of grass-fed cattle compared to grain-fed cattle, yet differences in lactate, glycogen and glucose were not detected. Further, increased (P < .05) ultimate pH values and lower (P < .05) lactate accumulations were noted when samples from grass-fed cattle were subjected to an in vitro glycolysis system. Muscle from grass-fed beef possessed nearly two-fold more (P < .05) succinate dehydrogenase and (P < .001) myoglobin than that of grain-fed cattle. These data show lean from grass-fed beef has greater enzymes reflective of oxidative metabolism and suggest dark lean from grass-fed cattle may be a function of more oxidative metabolism rather than a stress-related event antemortem.

Sustained IFN-I stimulation impairs MAIT cell responses to bacteria by inducing IL-10 during chronic HIV-1 infection

Mucosal-associated invariant T (MAIT) cells in HIV-1-infected individuals are functionally impaired by poorly understood mechanisms. Single-cell transcriptional and surface protein analyses revealed that peripheral MAIT cells from HIV-1-infected subjects were highly activated with the up-regulation of interferon (IFN)-stimulated genes as compared to healthy individuals. Sustained IFN-α treatment suppressed MAIT cell responses to Escherichia coli by triggering high-level interleukin-10 (IL-10) production by monocytes, which subsequently inhibited the secretion of IL-12, a crucial costimulatory cytokine for MAIT cell activation. Blocking IFN-α or IL-10 receptors prevented MAIT cell dysfunction induced by HIV-1 exposure in vitro. Moreover, blocking the IL-10 receptor significantly improved anti-Mycobacterium tuberculosis responses of MAIT cells from HIV-1-infected patients. Our findings demonstrate the central role of the IFN-I/IL-10 axis in MAIT cell dysfunction during HIV-1 infection, which has implications for the development of anti-IFN-I/IL-10 strategies against bacterial coinfections in HIV-1-infected patients.

Dietary supplementation with protected calcium effects production and egg quality of Hy-line brown laying hens

Context Currently, the commonly used dietary calcium sources are not sufficiently bioavailable to be used for eggshell formation or bone health in laying hens. Protected calcium, a blend of calcium and medium-chain fatty acids with matrix coating, may exert an effective absorption and metabolism ability for calcium consumption in the laying hen. Aims The present study was conducted to evaluate the effects of protected-calcium supplementation on egg production, egg quality, and serum calcium and phosphorus concentrations in laying hens. Methods In total, 144 Hy-line brown laying hens (25 weeks old) were randomly allotted to three treatments (8 replicates with 6 hens, 1 hen per cage) in a 10-week trial. Treatments consisted of corn–wheat–soybean meal-based basal diet with limestone (coarse limestone:fine limestone = 50:50) as a calcium source (CON) or basal diet supplemented with 0.5% (P1) or 1% (P2) protected calcium in substitution for an equal quantity of coarse limestone. Data were statistically analysed using linear and quadratic contrast with the GLM procedure of SAS. Probability values of &lt;0.05 indicate significance. Key results At Weeks 31–33 and 35, the cracked-egg rates were lower in the P1 and P2 groups than in the CON group (P &lt; 0.05; linear, P &lt; 0.05) and, at Weeks 29 and 34, the cracked-egg rates in the P2 group were also significantly (P &lt; 0.05) decreased. At Weeks 26, 30 and 32, the Haugh units in the P2 group were significantly (P &lt; 0.05) higher than those in the CON group. In addition, eggshell strength was increased significantly (P &lt; 0.05) in the P2 group at Weeks 26, 27 and 31–35. The serum calcium concentration of the P2 group was significantly (P &lt; 0.05) greater than that of the CON group in the morning. Conclusions In conclusion, a replacement of limestone with 1% protected calcium can increase eggshell quality. Implications Protected-calcium supplementation can be used in practice for decreasing the breakage of eggs.

Application of Quantitative Analysis of Diatoms in Lung Tissue for the Diagnosis of Drowning of Experimental Animals

Abstract

Objective To discuss the application value of diatom examination in lung tissue for the forensic diagnosis of drowning. Methods The experimental animals were divided randomly into drowning, postmortem submergence and dying on land group. Diatoms in lung tissue and drowning fluid were analyzed quantitatively by microwave digestion-vacuum filtration-automated scanning electron microscopy diatom examination method. The ratios of content of diatoms in lung tissue and drowning fluid （C_L/C_D ratio） were recorded. Results The C_L/C_D ratios of experimental rabbits in the drowning group （5.82±3.50） were much higher than that of postmortem submergence group （0.47±0.35）; the C_L/C_D ratios of different parts of the lung lobes of experimental pigs in the drowning group were higher than that of postmortem submergence group （P<0.05）; in seawater, brackish water, river fresh water and lake fresh water, the C_L/C_D ratios of experimental pigs in the drowning group were higher than that of postmortem submergence group （P<0.05）. In animal experiments, all the cases with C_L/C_D ratio >1.6 were from drowning group. Conclusion C_L/C_D ratio is an indicator with good application prospects in the diagnosis of drowning.

IMP3 promotes TNBC stem cell property through miRNA-34a regulation

OBJECTIVE

To explore the expression and function of insulin-like growth factor II (IGFII) mRNA binding protein (IMP3) in the Triple Negative Breast Cancer (TNBC).

MATERIALS AND METHODS

According to previously reported gene expression array, we found that IMP3 had significantly higher expression in the CD44+CD24-ESA+ cell cluster, tumor initiating cell or cancer stem cell (CSCs), compared to other tumor cells. Based on the GEO database (GEO accession No. GSE6883), we detected the mRNA levels of IMP 1,2 and 3 by quantitative polymerase chain reaction (q-PCR) in CD44+CD24-ESA+ cell cluster and other breast tumor cell clusters. Besides, we measured IMP3 expression in microsphere of breast cancer, which exerted more significant tumor stem cell properties. The effects of IMP3 on breast cancer cell stem cell properties were studied by RNA interference and overexpression approaches in vitro. Furthermore, we predicted and identified microRNA, which could target and regulate IMP3 from bioinformatics analysis, and verified the interaction by luciferase assays and rescue experiments.

RESULTS

Previously reported data showed that IMP3 expression was significantly upregulated in CD44+CD24-ESA+ cell cluster from breast cancer tissues. Besides, we found IMP3 had higher expression in mesenchymal cells rather than epithelial cells, which was also significantly elevated in SUM159 and T49D cell lines cultured as microsphere rather than adherent cells or differentiated cells. CD44+CD24-ESA+ cell cluster proportion was significantly decreased after silencing IMP3 in SUM1315, and its ability to develop into microsphere was significantly inhibited. By re-expressing IMP3 in SUM315, we restored the self-renewal capacity and tumorigenesis potential of SUM315. Through relative predicting website, we found several miRNAs which could regulate IMP3. miR-34a with highest score was chosen for further analysis. Mimicking miR-34a significantly downregulated IMP3 expression and inhibited its ability to develop into microsphere, while overexpressing IMP3 could rescue this process.

CONCLUSIONS

IMP3 plays a vital role in maintaining stem cell properties of breast cancer cells, which could be regulated by mir-34a.

Integrin α5 promotes migration and cisplatin resistance in esophageal squamous cell carcinoma cells

Cisplatin, as one of the front-line chemotherapeutic drugs, is employed for the treatment of esophageal squamous cell carcinoma (ESCC). However, the occurrence of cisplatin resistance and metastasis remain as challenges in clinical therapy. To investigate the mechanism involved in cisplatin resistance, in this study, we established cisplatin resistant cell lines (Res) from Eca109 and TE-1 parental cells (Par), and we observed that fibronectin (FN)-mediated cell migration and spreading abilities are significantly increased in Res cells when compared to Par cells. Furthermore, we found that the integrin α5 expression is remarkably upregulated in Res cells, and inhibition of α5 results in more apoptosis and endows the Res cells resensitize to cisplatin in vitro and in vivo. In a mechanistic manner, we identified the expression of BARD1 is significantly increased in Res cells, and silencing of BARD1 reverse the effects of α5 on cisplatin resistance. Moreover, we found that the α5/FAK/PI3K/AKT signal axis is activated in Res cells, which mediates the increased expression of BARD1, as well as the cisplatin resistance and cell survival. Thus, our results demonstrate that α5 is required for cisplatin resistance through the promotion of FAK/PI3K/AKT/BARD1 signaling to prevent cells from apoptosis and enhance the DNA damage repair ability. Taken together, our study provides plausible mechanisms of α5-mediated cisplatin resistance in ESCC cells, highlighting that inhibition of α5 may be a potential target for improving efficacy in cisplatin-based chemotherapy.

Role of GSPE in improving early cerebral vascular damage by inhibition of Profilin-1 expression in a ouabain-induced hypertension model

OBJECTIVE

Grape seed proanthocyanidin extract (GSPE), as one of the most popular natural drug extracted from the grape, has been reported to improve endothelial function and arteriosclerosis. However, little is known about the influence of GSPE on hypertension and vascular remodeling. Profilin-1, an Actin-binding protein, is closely involved in the remodeling of large vessels in ouabain-induced hypertension. To date, there is no effective prevention or treatment in place for the high incidence of ischemic stroke associated with hypertension. In this study, we aimed to determine the role of GSPE via inhibition Profilin-1 in ischemic cerebral cortices of ouabain-hypertension rats and potentially provide a new target to prevent stroke associated with hypertension.

MATERIALS AND METHODS

The blood pressure of male Sprague-Dawley (SD) rats was measured during a period of ouabain-induced hypertension. The expression of Profilin-1, vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) in the cerebral cortex were determined by quantitative Real Time-PCR (qRT-PCR) and Western blot. Histopathological and behavioral tests were also conducted.

RESULTS

Blood pressure elevation started at week 5 and reached clinical standards for hypertension at week 8. GSPE was proved to suppress Profilin-1 and VEGF levels through inhibition of Profilin-1-protein kinase B (AKT)-hypoxia inducible factor-1α (HIF-1α) signal pathway and promote eNOS expression. Moreover, the histopathological and ethiological improvement was observed in GSPE over-expression and Profilin-1 inhibition groups.

CONCLUSIONS

We detected that GSPE could improve cerebral vascular damage through inhibiting Profilin-1 in an ouabain-induced hypertension model.

Muscle from grass- and grain-fed cattle differs energetically

Insufficient acidification results in dark, firm, and dry beef. While this defect is often indicative of a stress event antemortem, muscle tissue may change in response to feeding regime. Longissimus dorsi muscle samples from 10 grain-fed and 10 grass-fed market weight, angus-crossbred beef cattle were collected postmortem. Lower (P < .05) L* and a* values were recorded for steaks from grass-fed cattle. Higher (P < .05) ultimate pH values were noted in lean of grass-fed cattle compared to grain-fed cattle, yet differences in lactate, glycogen and glucose were not detected. Further, increased (P < .05) ultimate pH values and lower (P < .05) lactate accumulations were noted when samples from grass-fed cattle were subjected to an in vitro glycolysis system. Muscle from grass-fed beef possessed nearly two-fold more (P < .05) succinate dehydrogenase and (P < .001) myoglobin than that of grain-fed cattle. These data show lean from grass-fed beef has greater enzymes reflective of oxidative metabolism and suggest dark lean from grass-fed cattle may be a function of more oxidative metabolism rather than a stress-related event antemortem.

Dual-Functional Liposomes with Carbonic Anhydrase IX Antibody and BR2 Peptide Modification Effectively Improve Intracellular Delivery of Cantharidin to Treat Orthotopic Hepatocellular Carcinoma Mice

Liposomal nanotechnology has a great potential to overcome the current major problems of chemotherapy. However, the lack of penetrability and targetability retards the successful delivery of liposomal carriers. Previously, we showed that BR2 peptide modification endowed cantharidin-loaded liposomes with intracellular penetration that enhanced the drug cytotoxic effects. Here, we aimed to improve the targeting delivery of drugs into cancer cells via highly expressed carbonic anhydrase IX (CA IX) receptors by modifying our previous catharidin-loaded BR2-liposomes with anti-CA IX antibody. A higher cellular uptake of dual-functional liposomes (DF-Lp) than other treatments was observed. Induction of CA IX over-expressing resulted in a higher cellular binding of DF-Lp; subsequently, blocking with excess antibodies resulted in a decreased cancer-cell association, indicating a specific targeting property of our liposomes towards CA IX expressed cells. After 3h tracking, most of the liposomes were located around the nucleus which confirmed the involvement of targeting intracellular delivery. Cantharidin loaded DF-Lp exhibited enhanced cytotoxicity in vitro and was most effective in controlling tumor growth in vivo in an orthotopic hepatocellular carcinoma model compared to other groups. Collectively, our results presented the advantage of the BR2 peptide and CA IX antibody combination to elevate the therapeutic potential of cantharidin loaded DF-liposomes.

Zinc mediates resuscitation of lactic acid-injured Escherichia coli by relieving oxidative stress

AIMS

Lactic acid is a natural antimicrobial in food industry, and also exists in fermented food. It was reported that sublethally injured Escherichia coli could survive in acidic conditions. When conditions become advantageous, injured E. coli can restore physiological function, which is a potential threat in food industry. Recovery is a necessary step for discriminating injured bacteria, but the resuscitation mechanism of injured bacteria is still unknown.

METHODS AND RESULTS

In our study, sublethal lactic acid treatment (pH 4·2, 60 min) posed oxidative stress on E. coli by decrease of superoxide dismutase (SOD) activity and overproduction of reactive oxygen species (ROS). Zinc with low concentration (1·0 mmol l^-1 ) significantly increased the recovery ratio of injured E.coli induced by lactic acid. The recovery ratios of injured cell in minimal A medium (minA) with 1·0 mmol l^-1 zinc reached to that with 3·0 mmol l^-1 catalase (CAT). Conversely, the addition of zinc chelator N, N, N', N'-tetrakis (2-pyridylmethyl) decreased the recovery ratio. Zinc accelerated resuscitation of injured E. coli by improving SOD activity, and decreasing ROS production. Deletion of sodC encoding Cu/ZnSOD, katE/katG encoding CAT or regulating gene rpoS significantly decreased the recovery ratio. Among all of the mutants in this study, ΔrpoS and ΔsodC showed the lowest recovery ratio, which means they played significant roles in the process of resuscitation.

CONCLUSION

We provided direct evidence that zinc mediated resuscitation of lactic acid-injured E. coli by relieving oxidative stress. Zinc can be used as a low-cost and effective agent to improve recovery ratio and detection efficiency of injured bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

Antibacterial agents are a challenge for bacteria, but bacteria can survive as a sublethally injured state under stresses. Using injured E. coli induced by lactic acid as a model organism, we validated the significant role of zinc on resuscitation of injured cells.