Impact of Sample Processing and Storage Conditions on RNA Quality of Fresh-Frozen Cancer Tissues

Background: A biobank is a central resource that supports basic and clinical research. RNA quality of fresh-frozen tissue specimens in the biobank is highly associated with the success of downstream applications. Therefore, it is very important to evaluate the impact of tissue processing and storage conditions on RNA quality. Methods: A total of 238 surgically removed tissue specimens, including esophagus, lung, liver, stomach, colon, and rectal cancer, were used to evaluate RNA quality. Two tissue homogenization methods, manual and TissueLyser, were compared and the impacts of temperature fluctuation, tissue types, storage period, and clinicopathological parameters on RNA quality were analyzed. Results: RNA integrity was not influenced by tissue homogenization methods and tissue types. However, RNA integrity number (RIN) values were significantly correlated with temperature fluctuation. When the power of a -80°C freezer was cut off, RNA integrity of frozen tissues was not significantly affected until the temperature increased to 0°C. When the temperature rose to room temperature and remained for 4 hours, RNA integrity was almost completely destroyed. In addition, various cancer tissues with short-term storage at -80°C (<5 years) or high tumor differentiation had higher RINs. Conclusions: Tissue processing and storage conditions affected RNA quality of fresh-frozen cancer tissues. It is necessary to keep storage temperature stable and keep specimens at ultralow temperatures during homogenization. Also, for a biobank containing multiple types of cancer tissue samples, it is better to store them in liquid nitrogen if the storage duration is more than 5 years.

Dynamic changes of soluble HLA-G and cytokine plasma levels in cervical cancer patients: potential role in cancer progression and immunotherapy

PURPOSE

Chronic inflammation has been proven to be an important factor in carcinogenesis. Cytokines are the central mediators in the inflammatory microenvironment, and their release may be influenced by soluble HLA-G (sHLA-G). The aim of this study was to monitor the dynamic process of these soluble factors in patients with cervical cancer at Taizhou Hospital of Zhejiang Province, trying to understand their relationship with diagnosis, treatment, and prognosis.

METHODS

We quantified plasma levels of sHLA-G and 12 cytokines using ELISA and flow cytometry, respectively, in the peripheral blood of patients with cervical cancer divided into three groups: preoperation, postoperation and clinical relapse. Healthy women were used as the control group. Data were analysed by non-parametric tests, receiver-operating characteristic (ROC) curves, and Kaplan-Meier plotter (log-rank test).

RESULTS

In this study, our findings showed that preoperation plasma levels of sHLA-G and the cytokines IL-6, IL-10, and IFN-γ in cervical cancer patients had a good discriminatory effect between cervical cancer patients and healthy women. It should be noted that plasma levels of sHLA-G, IL-6, and IL-10 were significantly decreased within 30 days after radical hysterectomy (P < 0.05). A positive correlation was observed between IL-6 and IL-10, IL-8 and IL-17 levels preoperatively. In contrast, sHLA-G levels were negatively correlated with IL-10 but not with other cytokines. An increased survival rate in patients with cervical cancer was associated with IL-5 < 1.70 pg/mL, IL-17 < 2.30 pg/mL, and IFN-α < 2.26 pg/mL preoperatively. In addition, our findings showed that the levels of cytokines IL-6, IL-8, IL-12p70, IL-17, and IFN-γ may be related to 5-year relapse rates and/or the metastasis of cervical cancer.

CONCLUSION

The current findings enhance our understanding of the dynamic process (preoperation, postoperation and clinical relapse) of sHLA-G and these cytokines in the plasma of patients with cervical cancer from diagnosis to prognosis. These biomarkers may play a potential therapeutic target role of such dynamic changes in the immunotherapy for cervical cancer.

First report of Fusarium proliferatum causing Root and Bulb Rot on tiller onion (Allium cepa L. var. Agrogatum Don) in China

Tiller onion is a biennial herb and a fascicular variety of onion. Tiller onion has strong tillering ability and can produce up to ten bulbs per plant. It is widely cultivated due to nutrition and special flavor. In July 2020, we observed a disease that seriously affected the normal growth of tiller onion in Halahai Town, Nongan County, Jilin Province, China. At least 70% of tiller onions in the field were affected by this disease. Aboveground parts of the symptomatic plants showed stunted growth, wilting and drying. Underground parts of infected plants were shown that onion increase tiller number but did not grow and expand. Root appeared red lesions and rot in severe cases. The bulb disc appeared brown to dark brown rot. Symptomatic roots were cut into 0.5 cm pieces and surface-sterilized by dipping in 75% ethanol for 60 s, 3% NaOCl for 3 min, and rinsing three times with sterile distilled water. Pieces were placed on potato dextrose agar (PDA) plates and incubated at 25±1℃ for 4 days. Fifteen isolates were obtained and pure-cultured through single-sporing. On PDA plates, the colonies initially had white aerial mycelia that then turned pale purple. The color of the colonies on the back of the plates was purple. Macroconidia were hyaline, falcate and 14.4 to 38.7 × 1.2 to 3.0 µm. Microconidia were hyaline, reniform or elliptic, unicellular or bicellular and were 7.62 to 19.61 µm in length, and 3.23 to 8.41 µm in width. Based on these morphological and culture characteristics, the causal agent was tentatively identified as F. proliferatum. To confirm the pathogen identity, segments of the internal transcribed spacer region of the rRNA gene ( ITS, primers ITS4 and ITS5, White et al., 1990), β-tubulin gene (TUB2, primers T1 and T2, O'Donnell and Cigelnik, 1997), and translation elongation factor 1-alpha gene (TEF-1α, primers EF1 and EF2 from O'Donnell et al., 1998) were amplified by PCR. Per the BLASTN search, TEF-1α (Accession No. OL355013), TUB2 (Accession No. OL355012), and ITS (Accession No. OL355011) queries showed 99.26%, 100%, and 99.82% homology to F. proliferatum GenBank accessions KU872098, MH398224, and MH997878, respectively. Pathogenicity of fifteen isolates of F. proliferatum from tiller onion was confirmed by inoculating healthy tiller onion roots and bulb disc with a spore suspension (1 × 106 spores/ml) produced on PDA. For each treatment, five plants were injected with 5 ml of spore suspension. Control plants (n=5) were injected with sterilized water. All plants were enclosed in plastic bags for 48 h in a greenhouse at 28℃ and 12 h/d light cycle. After 10 days, inoculated plants showed similar symptoms to those on the original diseased plants, while control plants remained symptomless. F. proliferatum was successfully re-isolated from symptomatic plants to fulfill Koch's postulates. Diseases caused by F. proliferatum are only reported in A. cepa. To our knowledge, this is the first report of F. proliferatum in Allium cepa L. var. agrogatum Don in China. Our findings are important for informed surveillance of the disease in China as F. proliferatum infection can not only reduce the quality and yield of tiller onion but also can contaminate the bulbs with harmful mycotoxins.

Prognostic Significance of Immune Checkpoints HLA-G/ILT-2/4 and PD-L1 in Colorectal Cancer

Immune checkpoint inhibitors (ICIs) have become a promising area of research for cancer treatment. In addition to the well-known ICIs targeting PD-1/PD-L1, HLA-G/ILT-2/-4 is relatively new immune checkpoint that has been evaluated in early clinical trials in patients with advanced solid tumors. In this study, the expression of HLA-G (n=157), ILT-2/4 (n=82), and PD-L1 (n=70) in epithelial cell adhesion molecule (EpCAM)-positive colorectal cancer (CRC) cells was analyzed by multicolor flow cytometry, and the prognostic significance of these molecules was evaluated. In EpCAM⁺ CRC cells, the median percentages of HLA-G, ILT-2, ILT-4, and PD-L1 were 14.90%, 67.70%, 8.55% and 80.30%, respectively. In addition, a positive correlation was observed between them (all p<0.001). Higher levels of these immune checkpoint proteins are associated with lymph node metastasis. In addition to the AJCC stage (p=0.001), Kaplan-Meier survival analysis showed that higher levels of HLA-G (p=0.041), ILT-2 (p=0.060), ILT-4 (p<0.001), PD-L1 (p=0.012), HLA-GILT4 (p<0.001) and ILT-2ILT-4 (p<0.001) were significantly associated with shorter survival of CRC patients. When CRC patients were stratified by early and advanced AJCC stages, HLA-G levels were only related to the survival among CRC patients with early disease stage (p=0.024), while ILT-4 levels were significant for both CRC patients with early (p=0.001) and advanced (p=0.020) disease stages. Multivariate cox regression analysis revealed that advanced AJCC stage (HR=2.435; p=0.005) and higher ILT-4 levels (HR=2.198; p=0.063) were independent risk factors for poor outcomes in patients with CRC. In summary, among the immune checkpoints, HLA-G/ILT-2/4 and PD-L1, ILT-4 is the most significant prognostic indicator of CRC. This finding indicated that a combination of immunotherapy strategies, such as ILT-4 blockade, could improve the clinical outcomes in patients with cancer. Moreover, multicolor flow cytometry can be employed as a reliable and efficient, alternative to immunohistochemistry, for evaluating the immune checkpoint proteins expressed in tumor lesions.

[Use of sofosbuvir-based regimens in the treatment of adolescents and children with chronic hepatitis C]

Sofosbuvir has ushered in a new era of hepatitis C treatment with its strong inhibition on the replication of hepatitis C virus, favorable safety profile and less interactions with other drugs. Sofosbuvir-based regimens have been included as the first-line therapies for the treatment of adults with chronic hepatitis C (CHC) in international guidelines. Available clinical trial data show that sofosbuvir with ribavirin and ledipasvir/sofosbuvir are highly efficacious and safe in CHC patients aged 3-17 years old; therefore, they can meet the unmet medical needs of adolescents and children with CHC in China. Furthermore, the pan-genotypic sofosbuvir/velpatasvir is being investigated in adolescents and children with CHC, which is expected to make the treatment in such patients more convenient upon approval.

Intratumor Heterogeneity of HLA-G Expression in Cancer Lesions

Signaling pathway between human leukocyte antigen (HLA)-G and immune inhibitory receptors immunoglobulin-like transcript (ILT)-2/4 has been acknowledged as one of immune checkpoints, and as a potential target for cancer immunotherapy. Like other immune checkpoints, inter- and even intratumor heterogeneity of HLA-G could render a rather complexity for HLA-G-target immunotherapy. However, little information for intratumor heterogeneity of HLA-G is available. In this study, HLA-G expression in a serial section of colorectal cancer (CRC) lesions from three CRC patients (each sample with serial section of 50 slides, 10 randomized slides for each antibody), three different locations within a same sample (five CRC), and three case-matched blocks that each includes 36 esophageal cancer samples, were evaluated with immunohistochemistry using anti-HLA-G antibodies (mAbs 4H84, MEM-G/1 and MEM-G/2 probing for all denatured HLA-G isoforms, 5A6G7, and 2A12 probing for denatured HLA-G5 and HLA-G6 isoforms). Our results revealed that, in addition to the frequently observed inter-tumor heterogeneity, intratumor heterogeneous expression of HLA-G is common in different areas within a tumor in CRC and esophageal cancer samples included in this study. Moreover, percentage of HLA-G expression probed with different anti-HLA-G antibodies also varies dramatically within a tumor. Given HLA-G has been considered as an important immune checkpoint, intratumor heterogeneity of HLA-G expression, and different specificity of anti-HLA-G antibodies being used among studies, interpretation and clinical significance of HLA-G expression in cancers should be with caution.

Intergrating conventional MRI, texture analysis of dynamic contrast-enhanced MRI, and susceptibility weighted imaging for glioma grading

BACKGROUND

The application of conventional magnetic resonance imaging (MRI) in glioma grading is limited and non-specific.

PURPOSE

To investigate the application values of MRI, texture analysis (TA) of dynamic contrast-enhanced MRI (DCE-MRI) and intratumoral susceptibility signal (ITSS) on susceptibility weighted imaging (SWI), alone and in combination, for glioma grading.

MATERIAL AND METHODS

Fifty-two patients with pathologically confirmed gliomas who underwent DCE-MRI and SWI were enrolled in this retrospective study. Conventional MRIs were evaluated by the VASARI scoring system. TA of DCE-MRI-derived parameters and the degree of ITSS were compared between low-grade gliomas (LGGs) and high-grade gliomas (HGGs). The diagnostic ability of each parameter and their combination for glioma grading were analyzed.

RESULTS

Significant statistical differences in VASARI features were observed between LGGs and HGGs ( P < 0.05), of which the enhancement quality had the highest area under the curve (AUC) (0.873) with 93.3% sensitivity and 80% specificity. The TA of DCE-MRI derived parameters were significantly different between LGGs and HGGs ( P < 0.05), of which the uniformity of K^trans had the highest AUC (0.917) with 93.3% sensitivity and 90% specificity. The degree of ITSS was significantly different between LGGs and HGGs ( P < 0.001). The AUC of the ITSS was 0.925 with 93.3% sensitivity and 90% specificity. The best discriminative power was obtained from a combination of enhancement quality, K^trans- uniformity, and ITSS, resulting in 96.7% sensitivity, 100.0% specificity, and AUC of 0.993.

CONCLUSION

Combining conventional MRI, TA of DCE-MRI, and ITSS on SWI may help to improve the differentiation between LGGs and HGGs.

Association of HLA-G 3' UTR polymorphism and expression with the progression of cervical lesions in human papillomavirus 18 infections

Background

Human leukocyte antigen (HLA)-G is an immune checkpoint molecule, which expression in cervical cancer cells enables them to escape immunosurveillance. To date, limited information has been published on the association of HLA-G genetic background in malignant cells with levels of HLA-G expression and the clinical outcome of patients.

Methods

We investigated the influence of the HLA-G 14 bp In/Del (rs66554220) and + 3142C/G (rs1063320) polymorphisms in 130 cases of HPV16 infection, 130 cases of HPV18 infection and 185 age-matched, unrelated, HPV-negative, and cytologically normal Chinese Han women. Case-matched cervical biopsy tissues were evaluated by immunohistochemistry.

Results

Our findings show that the frequency of alleles, 14 bp In (38.5% vs 29.2%, OR = 1.52, P < 0.05) and + 3142G (72.7% vs 57.0%, OR = 2.01, P < 0.05), were significantly increased in the HPV18-infected group compared with the control group. The HLA-G polymorphisms (alleles 14 bp In and + 3142G) are also associated with the progression of HPV18-related cervical lesions. Moreover, HLA-G expression increased from CIN1 to CIN2/3 lesions and was highest in patients with adenocarcinoma; however, a significant association between these characteristics and the HLA-G polymorphisms was not observed.

Conclusion

Our results support that the HLA-G 14 bp In and + 3142G alleles are risk factors for HPV18 infections and influence the progression of HPV18-related cervical lesions. This suggests that HLA-G-driven immune mechanisms play an important role in cervical carcinogenesis.

Genetic variability and oncogenic risk association of human papillomavirus type 58 E6 and E7 genes in Taizhou area, China

It is well recognized that the association of human papillomavirus (HPV) and cervical carcinogenesis is based on the presence of HPV DNA sequence. The E6 and E7 oncoproteins encoded by high-risk HPV types play a key role in carcinogenesis. HPV58 type accounts for a larger share of cervical disease in China, whereas data on HPV58 genetic variability in China is limited. We aimed to evaluate the diversity of HPV58 genetic variants by sequencing the entire E6 and E7 genes. Phylogenetic trees were constructed by Maximum likelihood method by MEGA 5.05 software. In this study, the overall HPV infection rate was 22.6% (2891/12780) in Southeast China and the prevalence of HPV58 infection rate was 2.6% (335/12780). 26 nucleotides substitutions were observed in E6 and E7 genes with 10 novel substitutions and 17 non-synonymous substitutions. We obtained 25 distinct variation patterns which the accession GenBank numbers as MH348918-MH348942. All of HPV58 variants belong to lineage A, while no lineage B, C and D were detected in Taizhou area, Southeast China. The sublineage A1, A2, and A3 variants were found in 136 (68.3%), 39 (19.6%), and 24 (12.1%) of HPV58 isolates, respectively. The sublineage A3 variants with T20I/G63S substitutions at E7 oncoprotein carried a significantly higher risk for high-grade cervical intraepithelial neoplasia (CIN2 or worse, CIN2+) when compared with other HPV58 variants (odds ratio = 4.41, P < 0.05). Nevertheless, there was no association between HPV58 (sub) lineages and cervical lesions. These data provide the critical characteristics of HPV58 variants to assist further investigation of carcinogenic association and the development of next generation vaccines and diagnostic assays in China.

[Analysis of the characteristics of lymphocyte subsets in peripheral blood among coal worker's pneumoconiosis patients]

Objective: To preliminary analysis of the characteristics of lymphocyte subsets in peripheral blood among 135 cases of coal worker's pneumoconiosis patients in Huainan mining area. Methods: The peripheral bloods of 135 cases of coal worker's pneumoconiosis patients and 112 cases of health examiners were collected. Flow cytometry was used to detect peripheral blood lymphocytes, T cell subsets and CD4(+)CD25(+) regulatory T cells. Results: Compared with the control group, CD64 index of granulocytes and lymphocytes was slightly higher. The total T cells (CD3(+)) increased in peripheral blood, CD4(+) expression was reduced and CD8(+) expression was increased in infection group, CD4(+)/CD8(+) ratio was inverted, the differences between the infection group and the control group were statistically significant (P<0.05) . There were significantly fewer NK (nature killer) and B cells, significantly more double negative T cells (DNT, CD3(+)CD4(-)CD8(-)) than the control group (P<0.05) . There was no statistically significant difference of CD4(+)CD25(+)CD127(+low)、CD4(+)CD25(+)CD127(+hi) and the ration of Treg/CD4(+)CD25(+)CD127(+hi) protein expression in peripheral blood in two groups (P>0.05) . Conclusion: The analysis of peripheral blood lymphocyte and subgroup is an ideal index to monitor the immune status of coal worker's pneumoconiosis patients. It has theoretical significance for studying the immune mechanism of pneumoconiosis and guiding clinical treatment.

Investigations of high order plasmonic resonance features of the nano hyper ring

A novel silver hyper ring and its complex nanostructures are designed and its plasmonic properties are investigated numerically. It is found that these hyper ring structures have relative stable optical features. The absorption cross section of the structure changes slightly when the direction and polarization of incident light is adjusting. For the complex structure, the position of each resonance peak does not present obvious change when the relative position of the inner hyper ring and outside larger ring changes. The result of the investigation has great significance for the production of practical nanostructures and the improvement of possible applications.

Lesion HLA-G5/-G6 isoforms expression in patients with ovarian cancer

HLA-G is an immune tolerant with seven isoforms. HLA-G expression was observed to be associated with tumor cell immune escaping, invasion and metastasis, and with poor prognosis in cancer patients. Different types of HLA-G isoforms could be expressed in clinical settings when meet different cellular and environmental conditions. Lesion total HLA-G expression detected by the monoclonal antibody (mAb) 4H84 was widely investigated in previous studies, while specific HLA-G isoforms such as HLA-G5/-G6 remains to be clarified. In this study, 118 primary ovarian cancer lesions were probed with mAb 5A6G7 which recognizes HLA-G5/-G6 was performed by immunohistochemistry. Data showed that HLA-G5/-G6 was expressed in 79.7% (94/118) of these ovarian cancer lesions, where HLA-G5/-G6 expression was observed in 75.7% (53/70) serous, 63.6% (7/11) mucinous cystadenocarcinoma and in 100% (11/11) endometrioid adenocarcinoma, in 85.7% (6/7) clear cell carcinoma, 100% (10/10) sex cord-stromal tumor and 77.8% (7/9) germ cell tumors. However, lesion HLA-G5/-G6 expression was unrelated to histological type, patient age, FIGO stage and patient survival. Unlike total HLA-G expression, no clinical significance of HLA-G5/-G6 expression in ovarian cancer lesion was observed in this study. Our findings indicated that different HLA-G isoforms might have different biological functions in malignancies.

Baicalein attenuates angiotensin II-induced cardiac remodeling via inhibition of AKT/mTOR, ERK1/2, NF-κB, and calcineurin signaling pathways in mice

BACKGROUND

Baicalein, a specific lipoxygenase (LOX) inhibitor, has anti-inflammatory and antioxidant effects. However, the functional role of baicalein in angiotensin II (Ang II)-induced hypertension and cardiac remodeling remains unclear. Here we investigated the effect of baicalein on cardiac hypertrophy and fibrosis and the underlying mechanism.

METHODS

Wild-type (WT) mice were injected with Ang II (1,200ng/kg/min) alone or together with 12/15-LOX inhibitor baicalein (25mg/kg) for 14 days. Histological examinations were performed on heart sections with hematoxylin and eosin, Masson's trichrome, wheat germ agglutinin staining, and immunohistochemistry. The messenger RNA (mRNA) expression of cytokines and protein levels were detected by real-time polymerase chain reaction (PCR) and western blot analysis respectively.

RESULTS

Ang II infusion significantly increased blood pressure but decreased cardiac contractile function reflected by fractional shortening% and ejection fraction% compared with saline-treated mice. Moreover, Ang II infusion resulted in marked cardiac hypertrophy and fibrosis, promoted accumulation of macrophages and T cells, the expression of proinflammatory cytokines and malondialdehyde (MDA) production. However, these actions were markedly reversed by administration of baicalein in mice. Mechanistically, the protective effects of baicalein were associated with the inhibition of inflammation, oxidative stress, and multiple signaling pathways (AKT/mTOR, ERK1/2, nuclear factor-κB (NF-κB), and calcineurin) in the Ang II-treated mice.

CONCLUSIONS

This study demonstrates that baicalein can significantly ameliorate Ang II-induced hypertension and cardiac remodeling, and may be a novel therapeutic drug for prevention of hypertensive heart diseases.

The identification of the biological characteristics of human ovarian cancer stem cells

OBJECTIVE

Identifying the biological characteristics of previously screened ovarian cancer cell line HO8910-derived stem cells.

MATERIALS AND METHODS

The pre-screening of ovarian cancer cell line HO8910-derived stem cells were subcultured (HO8910 cells were used as a control group) in serum-free medium. Firstly, the capacities of forming spheroids and self-renewal were observed. Then ovarian cancer stem cells (CSCs) were seeded in medium containing serum and cultured to observe the changes in their ability to differentiate. The stem cell-specific markers were also tested. Secondly, we tested the sensitivity of stem cells to cisplatin, doxorubicin, and mitoxantrone using drug susceptibility test. Finally, we inoculated the ovarian CSCs after passaging from culturing in serum-free media to NOD/SCID (non-obese diabetic/severe combined immunodeficient mice) mice in order to observe the tumorigenicity in vivo.

RESULTS

Ovarian CSCs cultured in serum-free medium are capable of forming stable passaged cells spheres and have strong ability of self-renewal and differentiation. Under the condition of serum-free medium culture, the expression levels of CDl33+, CD117+, ABCG2, Nanog, Oct4, and BCRP in ovarian cancer stem cell are significantly higher than the counterparts in HO8910 cells. With the increase of the ability of differentiation, the stem cell marker expression levels reduced. While the differentiation, potential marker-E-cadherin expression levels were significantly lower than the control group. With the increase of the ability to differentiate, E-cadherin expression level was increased. Ovarian CSCs have significant resistance to cisplatin, doxorubicin, and mitoxantrone. NOD/SCID nude mice experiments showed that ovarian cancer stem cell tumorigenicity was significantly higher than control cells and has a continuous tumorigenicity.

CONCLUSIONS

Comparing ovarian CSCs derived from HO8910 to HO8910 cells, the stem cells have significantly enhanced abilities of self-renewal, differentiation, in vivo tumorigenicity, highly expressed stem cell genes, and multidrug resistance.

NADPH oxidases mediate a cellular "memory" of angiotensin II stress in hypertensive cardiac hypertrophy

A long-term "memory" of hyperglycemic stress, even when glycemia is normalized, has been previously reported in diabetes. In this report we propose a similar hypothesis that exposure to continuous high angiotensin II (Ang II) results in a cellular "memory" in isolated cardiomyocytes and in the heart tissues, and we investigate the role of NADPH oxidases in this phenomenon. Continuous high Ang II for 3 days markedly increased cardiomyocyte size, TUNEL-positive apoptotic cardiomyocytes, expression of inflammatory cytokines, and oxidative stress. These deleterious effects were also observed in the memory condition (high Ang II for 2 days followed by normal medium for 1 day). Furthermore, in a mouse model, Ang II infusion for 3 weeks significantly increased cardiac hypertrophy, apoptosis, inflammation, and ROS generation but decreased cardiac function compared with control mice, and similar effects were also observed in mice in the memory condition. Importantly, blockade of NADPH oxidase using apocynin diminished the induction of high Ang II stress markers in isolated cardiomyocytes and in the mouse heart. These effects were associated with inhibition of NADPH oxidase-mediated AKT/mTOR/S6K and ERK signaling pathways. The present results demonstrate the hypothesis that exposure to continuous high Ang II results in a hypertensive cellular memory that remains, even when cells or mice are switched back to normal Ang II. This phenomenon was associated with NADPH oxidase-mediated oxidative stress.