Biomedical subjects

Dong Zhang

Publications and source records attributed to Dong Zhang.

At least 19 recordsLinked to original sources

PubMed2026

Deimplementation of inappropriate feeding practices in early care and education: a Hybrid Type 3 cluster-randomized trial.

BACKGROUND: The science of deimplementation-reducing harmful or ineffective practices-has focused almost exclusively on clinical prescribing, with no studies conducted in community or educational settings. Early care and education (ECE) settings offer a strategic venue for shaping eating behaviors, with children consuming up to 500 meals annually in these environments. However, ECE educators routinely use feeding practices that undermine self-regulation, including pressuring children to eat, rushing mealtimes, and offering food as reward. These practices contribute to food aversions, diminished self-regulation, and obesity risk. METHODS: We will conduct a Hybrid Type 3 cluster-randomized trial evaluating a co-designed deimplementation strategy package (WISE Words) across 88 ECE sites in Arkansas and Louisiana. Sites will be randomized 1:1 to WISE Words or usual practice, with usual practice sites receiving the intervention after two years (waitlist design). WISE Words includes six strategies: dynamic training using improvisation methods, peer learning collaboratives with goal setting, external facilitation, audit and feedback, environmental reminders, and tailored educational materials. The primary outcome is de-adoption of inappropriate feeding practices measured via direct mealtime observation (Table Talk). Secondary outcomes include adoption of evidence-based practices, acceptability, appropriateness, and sustainability at 12- and 24-months post-intervention. Child outcomes include Body Mass Index, skin carotenoid levels (Veggie Meter) willingness to try new foods (observed) and food neophobia (teacher and caregiver report). An explanatory sequential mixed methods design will test mechanisms of change derived from the Implementation Trust Building Theory of Change examining whether trust mediates strategy effects on outcomes. DISCUSSION: This trial extends deimplementation science into community settings by targeting culturally embedded behavioral practices rather than clinical prescribing behaviors. Results will inform approaches to shifting entrenched practices in ECE and similar settings while testing trust as a deimplementation mechanism. Sustainability assessments will address a notable gap, as few studies have examined whether deimplementation effects persist. TRIAL REGISTRATION: NCT07101321, July 20, 2025.

Humans↗

PubMed2026

Dietary Polyphenol Acteoside-Related Molecular Signatures in Clear Cell Renal Cell Carcinoma: Multi-Omics Profiling and Functional Validation of IMPDH1.

Clear cell renal cell carcinoma (ccRCC) is characterized by substantial metabolic and molecular heterogeneity, but the disease-relevant programs associated with acteoside, a dietary polyphenol, remain poorly understood. We integrated predicted acteoside targets with bulk, single-cell, and spatial transcriptomic data from ccRCC and combined molecular subtyping with cross-cohort machine-learning analysis. Acteoside-related signatures were preferentially enriched in malignant compartments and increased with tumor grade and stage. Consensus clustering identified two molecular subtypes with distinct biological and clinical features. C1 was associated with immune activation, metabolic activity, and more favorable survival, whereas C2 showed greater genomic instability, reduced renal epithelial differentiation, and poorer outcomes. We further benchmarked multiple machine-learning strategies and established a 10-gene prognostic model that retained predictive performance across independent cohorts, with IMPDH1 emerging as the strongest risk-associated feature. Functional experiments confirmed the biological relevance of IMPDH1: its knockdown suppressed ccRCC cell proliferation, DNA synthesis, colony formation, and migration, whereas overexpression produced the opposite effects. Together, these findings indicate that acteoside-related molecular signatures capture clinically relevant heterogeneity in ccRCC and provide a framework for linking dietary-polyphenol-related molecular space with tumor biology. The identification and functional validation of IMPDH1 further highlight its potential importance in ccRCC progression.

IMPDH1↗

PubMed2026

Clinical Efficacy and Learning Curve of Far-Lateral Approach (FLA) in Uni-Portal Non-Coaxial Spinal Endoscopic Surgery (UNSES) in the Treatment of Lumbar Degenerative Diseases: A Prospective Study.

BACKGROUND: Uniportal non-coaxial spinal endoscopic surgery (UNSES) via far-lateral approach (FLA) is an innovative minimally invasive procedure for lumbar degenerative diseases, particularly far-lateral disc herniation and foraminal stenosis. However, complex lateral lumbar anatomy and strict endoscope-instrument coordination create a distinct learning curve that may compromise early surgical efficiency and safety. This study aimed to evaluate the efficacy and safety, quantify the learning curve, and to provide clinical guidance for the standardized promotion and application of this technology. METHODS: A total of 40 consecutive patients with lumbar degenerative diseases who underwent UNSES via FLA by a single surgeon between January 2025 and December 2025 were included. All data were analyzed using SPSS 26.0 statistical software (IBM, USA). Primary outcomes included operation time, blood loss, fluoroscopy frequency, and intraoperative complication rate. Secondary outcomes were VAS, ODI, and modified Macnab criteria at 1, 3, and 6 months postoperatively. The learning curve and the inflection point of the learning curve was determined using cumulative sum (CUSUM) analysis. The differences in clinical indicators between early and proficient stage were compared. RESULT: Operation time, blood loss, and fluoroscopy times decreased significantly with case accumulation (p < 0.05). CUSUM identified an inflection point at the 16th case, after which operation time stabilized at (55.3 ± 8.6) min, much shorter than the early phase (89.5 ± 10.3) min (p < 0.001). Before the 16th case, the curve was in an upward trend; after the 16th case, the curve tended to be flat, indicating the proficiency stage. Postoperative VAS and ODI improved significantly than those before surgery at each follow-up time (p < 0.05). There was no significant difference in postoperative VAS score and ODI between the two groups at each follow-up time point (p > 0.05). The total complication rate was 12.5% (5/40), were cured by conservative treatment. The total excellent-good rate was 90.0% (36/40). L5/S1 and Bertolotti's syndrome were independent factors affecting the learning curve. CONCLUSION: UNSES via FLA is a safe and effective minimally invasive technique for treating complex lumbar degenerative diseases. It has a certain learning curve, and the inflection point is about the 16th case. After mastering the key techniques such as anatomical positioning, endoscopic manipulation and hemostasis, the surgeon can gradually reach the proficiency stage, with significantly improved surgical efficiency and clinical efficacy, and controllable complications. This study provides a theoretical basis for the clinical training and technology promotion of UNSES via FLA.

Humans↗

PubMed2026

Distal versus proximal radial access for diagnostic cerebral angiography: comparative outcomes and learning curve analysis.

BACKGROUND AND PURPOSE: Distal transradial access (dTRA) is an alternative to proximal transradial access (pTRA) for neuroangiography, but comparative real-world data and evidence on its early learning curve remain limited. We compared procedural performance and access-site complications between dTRA and pTRA and evaluated the early learning curve of dTRA. METHODS: We retrospectively analyzed 470 diagnostic cerebral angiography procedures, representing 421 unique patients, performed via radial access at a single center between January 2025 and February 2026, including 237 dTRA and 233 pTRA procedures. Baseline characteristics, including age, sex, body mass index (BMI) category, aortic arch type, and antiplatelet/anticoagulant use, procedural performance, and clinically assessed access-site events were compared between groups. Radial artery occlusion (RAO) was assessed by postoperative bedside pulse examination and confirmed with Doppler ultrasound when clinical findings were uncertain. Multivariable logistic regression was used to evaluate predictors of RAO, persistent bleeding or repeated compression, hand edema, and a composite access-site event endpoint. Because repeated procedures occurred in a subset of patients and event counts were limited, first-procedure sensitivity analysis and analyses of infrequent outcomes were interpreted cautiously. The dTRA learning process was assessed in the first 100 dTRA cases performed by a single operator using multivariable regression, cumulative sum (CUSUM) analysis, segmented trend analysis, and phase-based comparisons. RESULTS: Baseline characteristics were comparable between groups, including age, male sex, BMI category, aortic arch type, and antiplatelet/anticoagulant use. Compared with pTRA, dTRA was associated with more puncture attempts (3.0 [2.0-4.0] vs 2.0 [1.0-3.0], P < 0.001), longer puncture time (2.0 [1.0-5.0] vs 2.0 [1.0-3.0] min, P = 0.003), lower first-pass success (19.4% vs 35.2%, P < 0.001), and a higher crossover rate (11.4% vs 6.0%, P = 0.037). However, dTRA was associated with a lower clinically assessed RAO rate (2.5% vs 7.7%, P = 0.011). On multivariable analysis, pTRA was independently associated with higher odds of RAO (OR 3.27, 95% CI 1.26-8.49, P = 0.015) and the composite access-site event endpoint (OR 3.12, 95% CI 1.55-6.28, P = 0.001). Similar findings were observed in a sensitivity analysis restricted to the first procedure per patient. In the first 100 dTRA cases, cumulative dTRA experience was independently associated with shorter total procedure time (beta = -0.074 min/case, P = 0.009), while CUSUM and moving-average analyses suggested that the major learning effect occurred within approximately the first 10-15 cases. CONCLUSIONS: In this retrospective single-operator cohort, dTRA was associated with lower clinically assessed RAO than pTRA despite greater access difficulty. The early learning effect was mainly reflected in shorter total procedure time. These findings support the feasibility of dTRA but should be interpreted cautiously given the study's observational design and limited anatomical data.

Humans↗

PubMed2026

MdWRKY75 interacts with MdWOX11 to modulate root growth under salt stress in apple.

The root system is pivotal for plant development, enabling both vegetative growth and tolerance to abiotic stresses like salinity. However, the molecular mechanisms governing root adaptive development in response to salt stress remain poorly understood in apple (Malus domestica Borkh.). In this study, we identified the salt stress-responsive WRKY transcription factor MdWRKY75. Overexpression of MdWRKY75 in transgenic apple negatively regulates adventitious root (AR) formation and salt stress tolerance, whereas reducing MdWRKY75 expression yields the opposite phenotype. Moreover, MdWRKY75 directly binds to the promoter of MdSAUR15 (SMALL AUXIN UP RNA15) and transcriptionally represses the expression of MdSAUR15, which, when overexpressed, promotes AR formation and enhances salt stress tolerance. We further demonstrated that MdWRKY75 interacts with MdWOX11, a WUSCHEL-related homeobox (WOX) transcription factor, both in vitro and in vivo. MdWOX11 expression is upregulated and enhances AR formation under salt stress. Additionally, MdWOX11 reduces the binding of MdWRKY75 to the MdSAUR15 promoter, and alleviates the MdWRKY75-mediated inhibitory effect on MdSAUR15 expression. Collectively, our study provides a MdWOX11-MdWRKY75-MdSAUR15 module regulating root adaptation in response to salt stress in apple.

Malus↗

PubMed2025

Multiomic Analyses Reveal the Molecular Mechanisms of Arid Adaptation in a Desert Rodent Species.

Organisms living in desert habitats face multiple simultaneous pressures, such as high temperatures and arid, and the population dynamics and community diversity of small rodents are strongly affected by climate extremes. However, the potential mechanisms by which desert rodents adapt to arid remain largely unexplored. Here, we assembled a 3.18 Gb genome, including 25,812 protein-encoding genes, for Orientallactaga sibirica, which is widely distributed across both arid and semihumid environments in Eurasia. Orientallactaga sibirica has longer ears and hind limbs to enhance heat dissipation, which may be related to the positively selected genes, such as Fgf10, Fgf11, Hoxc4, Hoxd1, and Bmp4. The renal transcriptome revealed increased fat and carbohydrate metabolism for metabolic water production in O. sibirica residing in arid habitats. Pathways such as material metabolism, oxidative stress response, osmoregulation, and water and salt reabsorption were enriched in candidate genes, such as Avp, Ang, and Ace, under positive selection in O. sibirica. Moreover, amino acid replacement was observed in the protein sequences of seven candidate genes, including Aldh7a1, Lnpep, Wnk4, C1qc, and Awat2, and these specific amino acid replacements of genes such as Umod and Scnn1a were related to unique osmoregulation, osmotic protection, and water retention compensation mechanisms. Water deprivation under laboratory conditions induced the upregulation of Umod and Aldh7a1 expression, further supporting the results observed in the wild population. These findings demonstrate that the positively selected genes related to limb development and specific amino acid replacements in the genes Umod and Scnn1a for unique osmoregulation in the renal vascular system may contribute to arid adaptation in the desert rodent species O. sibirica. This study provides novel insights into the adaptive evolution of desert small mammals and can serve as a reference for future research on renal damage-related diseases, such as human kidney stones and salt-sensitive hypertension.

Animals↗

PubMed2022

DNA polymerase delta interacting protein 3 facilitates the activation and maintenance of DNA damage checkpoint in response to replication stress.

BACKGROUND: Replication stress response is crucial for the maintenance of a stable genome. POLDIP3 (DNA polymerase delta interacting protein 3) was initially identified as one of the DNA polymerase δ (Pol δ) interacting proteins almost 20 years ago. Using a variety of in vitro biochemical assays, we previously established that POLDIP3 is a key regulator of the enzymatic activity of Pol δ. However, the in vivo function of POLDIP3 in DNA replication and DNA damage response has been elusive. METHODS: We first generated POLDIP3 knockout (KO) cells using the CRISPR/Cas9 technology. We then investigated its biological functions in vivo using a variety of biochemical and cell biology assays. RESULTS: We showed that although the POLDIP3-KO cells manifest no pronounced defect in global DNA synthesis under nonstress conditions, they are sensitive to a variety of replication fork blockers. Intriguingly, we found that POLDIP3 plays a crucial role in the activation and maintenance of the DNA damage checkpoint in response to exogenous as well as endogenous replication stress. CONCLUSION: Our results indicate that when the DNA replication fork is blocked, POLDIP3 can be recruited to the stalled replication fork and functions to bridge the early DNA damage checkpoint response and the later replication fork repair/restart.

DNA Polymerase III↗

PubMed2007

Two noncellulosomal cellulases of Clostridium thermocellum, Cel9I and Cel48Y, hydrolyse crystalline cellulose synergistically.

The genome of Clostridium thermocellum contains a number of genes for polysaccharide degradation-associated proteins that are not cellulosome bound. The list includes beta-glucanases, glycosidases, chitinases, amylases and a xylanase. One of these 'soluble'-enzyme genes codes for a second glycosyl hydrolase (GH)48 cellulase, Cel48Y, which was expressed in Escherichia coli and biochemically characterized. It is a cellobiohydrolyse with activity on native cellulose such as microcrystalline and bacterial cellulose, and low activity on carboxymethylcellulose. It is about 100 times as active on amorphic cellulose and mixed-linkage barley beta-glucan compared with cellulase Cel9I. The enzyme Cel48Y shows a distinct synergism of 2.1 times with the noncellulosomal processive endoglucanase Cel9I on highly crystalline bacterial cellulose at a 17-fold excess of Cel48Y over Cel9I. These data show that C. thermocellum has, besides the cellulosome, the genes for a second cellulase system for the hydrolysis of crystalline cellulose that is not particle bound.

Cellulases↗

PubMed2006

New differentiation pathway for double-negative regulatory T cells that regulates the magnitude of immune responses.

Recent studies have demonstrated that in peripheral lymphoid tissues of normal mice and healthy humans, 1% to 5% of alphabeta T-cell receptor-positive (TCR(+)) T cells are CD4(-)CD8(-) (double-negative [DN]) T cells, capable of down-regulating immune responses. However, the origin and developmental pathway of DN T cells is still not clear. In this study, by monitoring CD4 expression during T-cell proliferation and differentiation, we identified a new differentiation pathway for the conversion of CD4(+) T cells to DN regulatory T cells. We showed that the converted DN T cells retained a stable phenotype after restimulation and that furthermore, the disappearance of cell-surface CD4 molecules on converted DN T cells was a result of CD4 gene silencing. The converted DN T cells were resistant to activation-induced cell death (AICD) and expressed a unique set of cell-surface markers and gene profiles. These cells were highly potent in suppressing alloimmune responses both in vitro and in vivo in an antigen-specific manner. Perforin was highly expressed by the converted DN regulatory T cells and played a role in DN T-cell-mediated suppression. Our findings thus identify a new differentiation pathway for DN regulatory T cells and uncover a new intrinsic homeostatic mechanism that regulates the magnitude of immune responses. This pathway provides a novel, cell-based, therapeutic approach for preventing allograft rejection.

Animals↗

PubMed2006

An association of a simultaneous nuclear and cytoplasmic localization of Fra-1 with breast malignancy.

BACKGROUND: Overexpression of Fra-1 in fibroblasts causes anchorage-independent cell growth and oncogenic transformation. A high level of Fra-1 expression is found in various tumors and tumorigenic cell lines, suggesting that Fra-1 may be involved in malignant progression. This study aimed to investigate the significance of Fra-1 expression in breast carcinogenesis. METHODS: The expression of Fra-1 was investigated by immunohistochemistry in neoplastic breast diseases ranging from benign fibroadenoma to very aggressive undifferentiated carcinoma. The correlations of Fra-1 expression with other indicators of breast carcinoma prognosis (ER, PR and ErbB2 receptors) were analyzed. RESULTS: All neoplastic breast tissues, either benign or malignant breast tissues, were nuclear immunoreactive for Fra-1-recognizing antibody. The pattern of Fra-1 expression by benign neoplastic cells was predominantly nuclear. However, the nuclear/cytoplasmic concomitant immunoreactivity was observed in all types of breast carcinomas. A clear shift in Fra-1 immunoreactivity, from an exclusively nuclear to a simultaneous nuclear and cytoplasmic localization was noticed in ~90% of breast carcinomas. CONCLUSION: The overall expression, pattern and intensity of Fra-1 proteins were correlated with breast oncogenesis. Overexpression of Fra-1, leading to a persistent high cytoplasmic accumulation, may play a role in the process of breast carcinogenesis.

Breast Neoplasms↗

PubMed2006

Evaluation of ultrasonic scattering in human cancellous bone by using a binary mixture model.

A weak scattering model based on small perturbations in a binary mixture is developed to estimate the ultrasonic scattering from human cancellous bone, which is modelled as a random isotropic continuum containing identical scatters. Ultrasonic scattering is determined by both velocity fluctuation and density fluctuation, when k(2)a(2) << 1 is satisfied. Two kinds of trabeculae thickness distributions, i.e. even distribution and Gauss distribution, are applied in the calculation of attenuation and backscattering. Frequency dependence of the backscatter coefficient is found to be Af(3.13) and Af(2.84) with the Gauss distribution and an even distribution, respectively. Both backscattering and attenuation change significantly against porosity for the case of high porosity. The predicted results are close to the measured ones from the literature. The errors of this theoretical model are also discussed in this paper.

Anisotropy↗

PubMed2006

Degradation mechanisms of benzo[a]pyrene and its accumulated metabolites by biodegradation combined with chemical oxidation.

A high degradation extent of benzo[a]pyrene (BaP) should not be considered as the sole desirable criterion for the bioremediation of BaP-contaminated soils because some of its accumulated metabolites still have severe health risks to human. Two main metabolites of BaP, benzo[a]pyrene-1,6-quinone (BP1,6-quinone) and 3-hydroxybenzo[a]pyrene (3-OHBP) were identified by high performance liquid chromatography (HPLC) with standards. This study was the first time that degradation of both BaP and the two metabolites was carried out by chemical oxidation and biodegradation. Three main phases during the whole degradation process were proposed. Hydrogen peroxide-zinc (H(2)O(2)-Zn), the fungus - Aspergillus niger and the bacteria - Zoogloea sp. played an important role in the different phases. The degradation parameters of the system were also optimized, and the results showed that the effect of degradation was the best when fungus-bacteria combined with H(2)O(2)-Zn, the concentration range of BaP in the cultures was 30-120mg/l, the initial pH of the cultures was 6.0. However, as co-metabolites, phenanthrene significant inhibited the degradation of BaP. This combined degradation system compared with the conventional method of degradation by domestic fungus only, enhanced the degradation extent of BaP by more than 20% on the 12d. The highest accumulation of BP1,6-quinone and 3-OHBP were reduced by nearly 10% in the degradation experiments, which further proved that the combined degradation system was more effective as far as joint toxicity of BaP and its metabolites are concerned.

Aspergillus↗

PubMed2006

Intramolecular arene epoxidation by phosphadioxiranes.

Singlet oxygen reacts with binaphthyl phosphine derivatives such as 1,1'-binaphthyl di-tert-butyl phosphine to form the corresponding binaphthyl-2-oxide phosphine oxides. This new intramolecular arene epoxidation reaction proceeds with complete retention of stereochemistry. The binaphthyl-2-oxide di-tert-butyl phosphine oxide undergoes a slow "NIH-rearrangement" to form the corresponding hydroxylated product. A transient phosphadioxirane intermediate has been directly observed by low-temperature NMR. Kinetic analyses show that all of the phosphadioxirane intermediate is converted to product. [reaction: see text]

Catalysis↗

PubMed2006

An evaluation of the effect of a gastric ischemia-reperfusion model with laser Doppler blood perfusion imaging.

The objectives of this study are to establish a gastric ischemia-reperfusion model and test it using the laser Doppler blood perfusion imaging (LDPI) method and to evaluate the role of the LDPI technique in the measure of gastric blood circulation. The right gastric artery of the rat was clamped for 30 min and then reperfused. The LDPI was used to display the blood circulation of the whole gastric surface during this process. The blood flow perfusion image of the gastric surface was displayed clearly. After the right gastric artery was clamped, the blood flow perfusion on the gastric surface decreased very significantly until the clamp was loosened. Following reperfusion, the blood flow suddenly increased. Within the first 10 min, the blood-flow perfusion exceeded the level before the clamping and then gradually became smooth and steady. The right gastric artery is a main pathway for gastric blood supply. LDPI can display successfully the blood circulation state of the stomach and the course of ischemia-reperfusion of a large area with an image.

Animals↗

PubMed2006

A genomewide search finds major susceptibility loci for nicotine dependence on chromosome 10 in African Americans.

Epidemiological studies have demonstrated that genetic factors account for at least 50% of the liability for nicotine dependence (ND). Although several linkage studies have been conducted, all samples to date were primarily of European origin. In this study, we conducted a genomewide scan of 1,261 individuals, representing 402 nuclear families, of African American (AA) origin. We examined 385 autosomal microsatellite markers for ND, which was assessed by smoking quantity (SQ), the Heaviness of Smoking Index (HSI), and the Fagerstrom Test for ND (FTND). After performing linkage analyses using various methods implemented in the GENEHUNTER and S.A.G.E. programs, we found a region near marker D10S1432 on chromosome 10q22 that showed a significant linkage to indexed SQ, with a maximum LOD score of 4.17 at 92 cM and suggestive linkage to HSI, SQ, and log-transformed SQ. Additionally, we identified three regions that met the criteria for suggestive linkage to at least one ND measure: on chromosomes 9q31 at marker D9S1825, 11p11 between markers D11S1993 and D11S1344, and 13q13 between markers D13S325 and D13S788. Other locations on chromosomes 15p11, 17q25, and 18q12 exhibited some evidence of linkage for ND (LOD >1.44). The four regions with significant or suggestive linkage were positive for multiple ND measures by multiple statistical methods. Some of these regions have been linked to smoking behavior at nominally significant levels in other studies, which provides independent replication of the regions for ND in different cohorts. In summary, we found significant linkage on chromosome 10q22 and suggestive linkage on chromosomes 9, 11, and 13 for major genetic determinants of ND in an AA sample. Further analysis of these positive regions by fine mapping and/or association analysis is thus warranted. To our knowledge, this study represents the first genomewide linkage scan of ND in an AA sample.

Adolescent↗

PubMed2006

A role for the deubiquitinating enzyme USP28 in control of the DNA-damage response.

The Chk2-p53-PUMA pathway is a major regulator of DNA-damage-induced apoptosis in response to double-strand breaks in vivo. Through analysis of 53BP1 complexes we have discovered a new ubiquitin protease, USP28, which regulates this pathway. Using a human cell line that faithfully recapitulated the Chk2-p53-PUMA pathway, we show that USP28 is required to stabilize Chk2 and 53BP1 in response to DNA damage. In this cell line, both USP28 and Chk2 are required for DNA-damage-induced apoptosis, and they accomplish this in part through regulation of the p53 induction of proapoptotic genes like PUMA. Our studies implicate DNA-damage-induced ubiquitination and deubiquitination as a major regulator of the DNA-damage response for Chk2, 53BP1, and a number of other proteins in the DNA-damage checkpoint pathway, including several mediators, such as Mdc1, Claspin, and TopBP1.

Adaptor Proteins, Signal Transducing↗

PubMed2006

The exonuclease TREX1 is in the SET complex and acts in concert with NM23-H1 to degrade DNA during granzyme A-mediated cell death.

Granzyme A (GzmA) activates a caspase-independent cell death pathway with morphological features of apoptosis. Single-stranded DNA damage is initiated when the endonuclease NM23-H1 becomes activated to nick DNA after granzyme A cleaves its inhibitor, SET. SET and NM23-H1 reside in an endoplasmic reticulum-associated complex (the SET complex) that translocates to the nucleus in response to superoxide generation by granzyme A. We now find the 3'-to-5' exonuclease TREX1, but not its close homolog TREX2, in the SET complex. TREX1 binds to SET and colocalizes and translocates with the SET complex. NM23-H1 and TREX1 work in concert to degrade DNA. Silencing NM23-H1 or TREX1 inhibits DNA damage and death of cells treated with perforin (PFN) and granzyme A, but not of cells treated with perforin and granzyme B (GzmB). After granzyme A activates NM23-H1 to make single-stranded nicks, TREX1 removes nucleotides from the nicked 3' end to reduce the possibility of repair by rejoining the nicked ends.

Cell Death↗

PubMed2006

Nonlinear absorption in biological tissue for high intensity focused ultrasound.

In recent years the propagation of the high intensity focused ultrasound (HIFU) in biological tissue is an interesting area due to its potential applications in non-invasive treatment of disease. The base principle of these applications is the heat effect generated by ultrasound absorption. In order to control therapeutic efficiency, it is important to evaluate the heat generation in biological tissue irradiated by ultrasound. In his paper, based on the Khokhlov-Zabolotkaya-Kuznetsov (KZK) equation in frequency-domain, the numerical simulations of nonlinear absorption in biological tissues for high intensity focused ultrasound are performed. We find that ultrasound thermal transfer effect will be enhanced with the increasing of initial acoustic intensity due to the high harmonic generation. The concept of extra absorption factor is introduced to describe nonlinear absorption in biological tissue for HIFU. The theoretical results show that the heat deposition induced by the nonlinear theory can be nearly two times as large as that predicated by linear theory. Then, the influence of the diffraction effect on the position of the focus in HIFU is investigated. It is shown that the sound focus moves toward the transducer compared with the geometry focus because of the diffraction of the sound wave. The position of the maximum heat deposition is shifted to the geometry focus with the increase of initial acoustic intensity because the high harmonics are less diffraction. Finally, the temperature in the porcine fat tissue changing with the time is predicated by Pennes' equation and the experimental results verify the nonlinear theoretical prediction.

Adipose Tissue↗