Light-Driven Biomimetic Nanomotors for Enhanced Photothermal Therapy.

Nanotechnology-based strategy has recently drawn extensive attention for the therapy of malignant tumors due to its distinct strengths in cancer diagnosis and treatment. However, the limited intratumoral permeability of nanoparticles is a major hurdle to achieving the desired effect of cancer treatment. Due to their superior cargo towing and reliable penetrating property, micro-/nanomotors (MNMs) are considered as one of the most potential candidates for the coming generation of drug delivery platforms. Here, near-infrared (NIR)-actuated biomimetic nanomotors (4T1-JPGSs-IND) are fabricated successfully and we demonstrate that 4T1-JPGSs-IND selectively accumulate in homologous tumor regions due to the effective homing ability. Upon laser irradiation, hyperthermia generated by 4T1-JPGSs-IND leads to self-thermophoretic motion and photothermal therapy (PTT) to ablate tumors with a deep depth, thereby improving the photothermal therapeutic effect for cancer management. The developed nanomotor system with multifunctionalities exhibits promising potential in biomedical applications to fight against various diseases.

Shortcuts to adiabatic soliton compression in active nonlinear Kerr media.

We implement variational shortcuts to adiabaticity for optical pulse compression in an active nonlinear Kerr medium with distributed amplification and spatially varying dispersion and nonlinearity. Starting with the hyperbolic secant ansatz, we employ a variational approximation to systematically derive dynamical equations, establishing analytical relationships linking the amplitude, width, and chirp of the pulse. Through the inverse engineering approach, we manipulate the distributed gain/loss, nonlinearity and dispersion profiles to efficiently compress the optical pulse over a reduced distance with high fidelity. In addition, we explore the dynamical stability of the system to illustrate the advantage of our protocol over conventional adiabatic approaches. Finally, we analyze the impact of tailored higher-order dispersion on soliton self-compression and derive physical constraints on the final soliton width for the complementary case of soliton expansion. The broader implications of our findings extend beyond optical systems, encompassing areas such as cold-atom and magnetic systems highlighting the versatility and relevance of our approach in various physical contexts.

An integrated model incorporating deep learning, hand-crafted radiomics and clinical and US features to diagnose central lymph node metastasis in patients with papillary thyroid cancer.

OBJECTIVE: To evaluate the value of an integrated model incorporating deep learning (DL), hand-crafted radiomics and clinical and US imaging features for diagnosing central lymph node metastasis (CLNM) in patients with papillary thyroid cancer (PTC). METHODS: This retrospective study reviewed 613 patients with clinicopathologically confirmed PTC from two institutions. The DL model and hand-crafted radiomics model were developed using primary lesion images and then integrated with clinical and US features selected by multivariate analysis to generate an integrated model. The performance was compared with junior and senior radiologists on the independent test set. SHapley Additive exPlanations (SHAP) plot and Gradient-weighted Class Activation Mapping (Grad-CAM) were used for the visualized explanation of the model. RESULTS: The integrated model yielded the best performance with an AUC of 0.841. surpassing that of the hand-crafted radiomics model (0.706, p < 0.001) and the DL model (0.819, p = 0.26). Compared to junior and senior radiologists, the integrated model reduced the missed CLNM rate from 57.89% and 44.74-27.63%, and decreased the rate of unnecessary central lymph node dissection (CLND) from 29.87% and 27.27-18.18%, respectively. SHAP analysis revealed that the DL features played a primary role in the diagnosis of CLNM, while clinical and US features (such as extrathyroidal extension, tumour size, age, gender, and multifocality) provided additional support. Grad-CAM indicated that the model exhibited a stronger focus on thyroid capsule in patients with CLNM. CONCLUSION: Integrated model can effectively decrease the incidence of missed CLNM and unnecessary CLND. The application of the integrated model can help improve the acceptance of AI-assisted US diagnosis among radiologists.

A bimodal nomogram as an adjunct tool to reduce unnecessary breast biopsy following discordant ultrasonic and mammographic BI-RADS assessment.

OBJECTIVE: To develop a bimodal nomogram to reduce unnecessary biopsies in breast lesions with discordant ultrasound (US) and mammography (MG) Breast Imaging Reporting and Data System (BI-RADS) assessments. METHODS: This retrospective study enrolled 706 women following opportunistic screening or diagnosis with discordant US and MG BI-RADS assessments (where one assessed a lesion as BI-RADS 4 or 5, while the other assessed the same lesion as BI-RADS 0, 2, or 3) from two medical centres between June 2019 and June 2021. Univariable and multivariable logistic regression analyses were used to develop the nomogram. DeLong's and McNemar's tests were used to assess the model's performance. RESULTS: Age, MG features (margin, shape, and density in masses, suspicious calcifications, and architectural distortion), and US features (margin and shape in masses as well as calcifications) were independent risk factors for breast cancer. The nomogram obtained an area under the curve of 0.87 (95% confidence interval (CI), 0.83-0.91), 0.91 (95% CI, 0.87 - 0.96), and 0.92 (95% CI, 0.86-0.98) in the training, internal validation, and external testing samples, respectively, and demonstrated consistency in calibration curves. Coupling the nomogram with US reduced unnecessary biopsies from 74 to 44% and the missed malignancies rate from 13 to 2%. Similarly, coupling with MG reduced missed malignancies from 20 to 6%, and 63% of patients avoided unnecessary biopsies. Interobserver agreement between US and MG increased from - 0.708 (poor agreement) to 0.700 (substantial agreement) with the nomogram. CONCLUSION: When US and MG BI-RADS assessments are discordant, incorporating the nomogram may improve the diagnostic accuracy, avoid unnecessary breast biopsies, and minimise missed diagnoses. CLINICAL RELEVANCE STATEMENT: The nomogram developed in this study could be used as a computer program to assist radiologists with detecting breast cancer and ensuring more precise management and improved treatment decisions for breast lesions with discordant assessments in clinical practice. KEY POINTS: • Coupling the nomogram with US and mammography improves the detection of breast cancers without the risk of unnecessary biopsy or missed malignancies. • The nomogram increases mammography and US interobserver agreement and enhances the consistency of decision-making. • The nomogram has the potential to be a computer program to assist radiologists in identifying breast cancer and making optimal decisions.

High-grade cervical lesions diagnosed by JAM3/PAX1 methylation in high-risk human papillomavirus-infected patients. / é«˜å±åž‹äººä¹³å¤´ç˜¤ç— æ¯’æ„ŸæŸ“æ‚£è€ å®«é¢ˆè„±è½ç»†èƒžJAM3/PAX1é«˜ç”²åŸºåŒ–è¯Šæ–­å®«é¢ˆé«˜çº§åˆ«ç— å˜.

OBJECTIVES: Currently, traditional cervical cancer screening methods, such as high-risk human papillomavirus testing and liquid based cytology (LBC), still possess limitations. This study aims to identify new diagnostic biomarkers to achieve the goal of "precision screening" via exploring the clinical value of DNA methylation [ΔCtP: paired box gene 1 (PAX1)and ΔCtJ: junctional adhesion molecule 3 (JAM3)] detection in cervical exfoliated cells for the diagnosis of high-grade cervical lesions. METHODS: A total of 136 patients who underwent gynecological examinations in the vaginal room of the Department of Gynecology at the Third Xiangya Hospital of Central South University from June 2021 to June 2022 were retrospectively studied. Among them, 122 patients had non-high-grade cervical lesions, and 14 patients had high-grade cervical lesions. The variables included general information (age, body mass index, and menopause status), LBC, high-risk human papillomavirus, cervical tissue pathology, vaginal examination results, and the ΔCt values of JAM3 and PAX1 gene methylation. Logistic regression analysis was used to identify the factors affecting the diagnosis of high-grade cervical lesions, followed by correlation analysis and construction of a conditional inference tree model. RESULTS: Logistic regression analysis showed that the methylation ΔCt values of PAX1 and JAM3 genes and LBC detection results were statistically significant between the high-grade cervical lesions group and the non-high-grade cervical lesions group (all P<0.05). Correlation analysis revealed a negative correlation between cervical pathological changes and ΔCtP (r=-0.36, P<0.001), ΔCtJ (r=-0.448, P<0.001), LBC (r=-0.305, P<0.001), or bacterial diversity (r=-0.183, P=0.037). The conditional inference tree showed that when ΔCtJ>10.13, all of patients had non-high-grade cervical lesions, while ΔCtP>6.22, the number of non-high-grade lesions accounted for 97.5% (117/120), and high-grade lesions accounted for only 2.5% (3/120). When ΔCtJ>8.61 and LBC were atypical squamous cell of undetermined significance or negative for intraepithelial lesions or malignancy (NILM), 105 (99.1%) patients were non-high-grade cervical lesions, only 1 (0.9%) patient was high-grade lesion. When the results of LBC were high-grade lesions, only 9 patients' histopathological examination was the high-grade lesions and 3 non-high-grade lesions. When LBC indicated low-grade lesions, atypical squamous cell of undetermined significance, no intraepithelial lesions, and ΔCtP>6.22, 117 (97.5%) of patients' histopathological examination was the non-high-grade lesions. CONCLUSIONS: The JAM3/PAX1 gene methylation test can be used independently for the stratified diagnosis of high-grade/non-high-grade cervical lesions in women with high-risk human papillomavirus infection, independent of the cytological results of cervical excision. The JAM3/PAX1 gene methylation test can also be used in combination with LBC to make up for the shortcomings of low sensitivity of LBC. In addition, the application of methylation kit in large-scale cervical cancer screening in the future will be good to the detection of more patients with high-grade cervical lesions, and achieve early screening and early treatment for cervical lesions/cancer.

Inhibitory effects of simeprevir on Staphylococcusepidermidis and itsbiofilm in vitro. / è¥¿å’ªåŒ¹éŸ¦å¯¹è¡¨çš®è‘¡è„çƒèŒåŠå ¶ç”Ÿç‰©è†œçš„ä½“å¤–æŠ‘åˆ¶ä½œç”¨.

OBJECTIVES: Staphylococcus epidermidis (S. epidermidis) is a Gram-positive opportunistic pathogen that often causes hospital infections. With the abuse of antibiotics, the resistance of S. epidermidis gradually increases, and drug repurposing has become a research hotspot in the treating of refractory drug-resistant bacterial infections. This study aims to study the antimicrobial and antibiofilm effects of simeprevir, an antiviral hepatitis drug, on S. epidermidis in vitro. METHODS: The micro-dilution assay was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of simeprevir against S. epidermidis. Crystal violet staining assay was used to detect the biofilm inhibitory effect of simeprevir. The antimicrobial activity of simeprevir against S. epidermidis and its biofilm were explored by SYTO9/PI fluorescent staining. The combined effect between simeprevir and gentamycin was assessed by checkerboard assay and was confirmed by time-inhibition assay. RESULTS: Simeprevir showed significant antimicrobial effects against S. epidermidis type strains and clinical isolates with the MIC and MBC at 2-16 µg/mL and 4-32 µg/mL, respectively. The antimicrobial effects of simeprevir were confirmed by SYTO9/PI staining. Simeprevir at MIC could significantly inhibit and break the biofilm on cover slides. Similarly, simeprevir also significantly inhibit the biofilm formation on the surface of urine catheters either in TSB [from (0.700±0.020) to (0.050±0.004)] (t=54.03, P<0.001), or horse serum [from (1.00±0.02) to (0.13±0.01)] (t=82.78, P<0.001). Synergistic antimicrobial effect was found between simeprevir and gentamycin against S. epidermidis with the fractional inhibitory concentration index of 0.5. CONCLUSIONS: Simeprevir shows antimicrobial effect and anti-biofilm activities against S. epidermidis.

Magnesium-Based Micromotors as Hydrogen Generators for Precise Rheumatoid Arthritis Therapy.

Hydrogen therapy is an emerging and highly promising strategy for the treatment of inflammation-related diseases. However, nonpolarity and low solubility of hydrogen under the physiological conditions results in a limited therapeutic effect. Herein, we develop a biocompatible magnesium micromotor coated with hyaluronic acid as a hydrogen generator for precise rheumatoid arthritis management. The hydrogen bubbles generated locally not only function as a propellant for the motion but also function as the active ingredient for reactive oxygen species (ROS) and inflammation scavenging. Under ultrasound guidance, the micromotors are injected intra-articularly, and the dynamics of the micromotors can be visualized. By scavenging ROS and inflammation via active hydrogen, the oxidative stress is relieved and the levels of inflammation cytokines are reduced by our micromotors, showing prominent therapeutic efficacy in ameliorating joint damage and suppressing the overall arthritis severity toward a collagen-induced arthritis rat model. Therefore, our micromotors show great potential for the therapy of rheumatoid arthritis and further clinical transformation.

Propensity-score-matching analysis to compare efficacy and safety between 16-gauge and 18-gauge needle in ultrasound-guided biopsy for peripheral pulmonary lesions.

BACKGROUND: Definitive diagnosis of peripheral pulmonary lesions (PPLs) depends on the histological analysis of the pleural biopsy sample. Ultrasound (US)-guided sampling is now standard practice in the clinical setting. However, determining a suitable needle size and sampling times to improve the efficacy and safety of the biopsy remains challenging. Here, we compared the efficacy between 16- and 18-gauge core biopsy needles in US-guided percutaneous transthoracic biopsy for PPLs on histological diagnosis and procedure-related complications. MATERIALS AND METHODS: In total, 1169 patients (767 men, 402 women; mean age, 59.4 ± 13.2 years) who received biopsy for PPLs between September 2011 and February 2019 were included. The propensity score matching (PSM) analysis was performed to adjust the baseline differences, and the rate of successful specimen assessment and complications were compared between the 16-gauge (249 patients) and 18-gauge (920 patients) groups. The number of pleural surfaces crossed (NOPSC) was defined as the number of times the visceral pleural surface was transgressed. Stratified analysis was performed based on NOPSC. RESULTS: The overall success rate was 92.0% (1076/1169). The overall complication rate was 9.6%, including pneumothorax, hemorrhage, and vasovagal reaction, which occurred in 2.5% (29/1169), 6.6% (77/1169), and 0.5% (6/1169) of the patients, respectively. When NOPSC was 1 or > 2, the success and complication rates in the 16-gauge group were comparable to those of the 18-gauge group (all P > 0.05). When the NOPSC was 2, the success rate in the 16-gauge group was significantly higher than that in the 18-gauge group (P = 0.017), whereas the complication rate was comparable (P > 0.05). CONCLUSION: Higher success rate could be achieved using a 16-gauge than an 18-gauge core biopsy needle in the US-guided percutaneous transthoracic biopsy for PPLs when the NOPSC was 2. We recommend using 16-gauge needles with 2 times of needle passes in biopsy for PPLs in clinical practice.

Critical appraisal of the International Prophylaxis Study Group magnetic resonance image scale for evaluating haemophilic arthropathy.

A goal of the International Prophylaxis Study Group (IPSG) is to provide an accurate instrument to measure MRI-based disease severity of haemophilic arthropathy at various time points, so that longitudinal changes in disease severity can be identified to support decisions on treatment management. We review and discuss in this paper the evaluative purpose of the IPSG MRI scale in relation to its development and validation processes so far. We also critically appraise the validity, reliability and responsiveness of using the IPSG MRI scale in different clinical and research settings, and whenever applicable, compare these clinimetric properties of the IPSG MRI scale with those of its precursors, the compatible additive and progressive MRI scales.

Reconfiguration of Dynamic Functional Connectivity in Sensory and Perceptual System in Schizophrenia.

Schizophrenia is thought as a self-disorder with dysfunctional brain connectivity. This self-disorder is often attributed to high-order cognitive impairment. Yet due to the frequent report of sensorial and perceptual deficits, it has been hypothesized that self-disorder in schizophrenia is dysfunctional communication between sensory and cognitive processes. To further verify this assumption, the present study comprehensively examined dynamic reconfigurations of resting-state functional connectivity (rsFC) in schizophrenia at voxel level, region level, and network levels (102 patients vs. 124 controls). We found patients who show consistently increased rsFC variability in sensory and perceptual system, including visual network, sensorimotor network, attention network, and thalamus at all the three levels. However, decreased variability in high-order networks, such as default mode network and frontal-parietal network were only consistently observed at region and network levels. Taken together, these findings highlighted the rudimentary role of elevated instability of information communication in sensory and perceptual system and attenuated whole-brain integration of high-order network in schizophrenia, which provided novel neural evidence to support the hypothesis of disrupted perceptual and cognitive function in schizophrenia. The foci of effects also highlighted that targeting perceptual deficits can be regarded as the key to enhance our understanding of pathophysiology in schizophrenia and promote new treatment intervention.

Flow evaluation of STA-MCA bypass using quantitative ultrasonography: An alternative to standard angiography for follow up of bypass graft.

PURPOSE: To date, digital subtraction angiography (DSA) has been considered as the gold imaging modality for assessing graft patency after extracranial-intracranial bypass. The utility of a noninvasive and quantitative method of assessing graft flow postoperatively was evaluated by using quantitative ultrasonography. METHOD: All STA-MCA bypass surgery performed over a 5-year period at a single institution were reviewed. Measured by duplex ultrasonography, pre-operative (day1) and post-operative (day1, day7, 3month and 6 month) graft blood flow rates were recorded and analyzed. Results were correlated to Matsushima grade determined by DSA performed within 24 h when ultrasonography was conducted to confirm the graft function. RESULTS: 100 patients with 131 operated hemispheres were included in this study. The mean flow rates in the STA graft on pre-operative day1, post-operative day 1 and 7, at 3- and 6-month postoperatively were 24.1, 106.7, 112.6, 97.4 and 79.7 ml/min respectively. The mean post-operative flow in the STA graft graded as A/B/C were significantly different (168.0 ± 34.8 ml/min, 91.0 ± 15.5, 42.1 ± 17.2 ml/min, respectively, p = 0.000). 124.5 ml/min and 65.5 ml/min are good cut-off value for predicting post-operative graft Matsushima grade. The analysis also showed excellent agreement between ultrasonography and DSA for assessing bypass function (κ = 0.78). CONCLUSIONS: The patency of the STA grafts can be assessed noninvasively by quantitative ultrasonography, which results are comparable to those of conventional DSA. This, therefore, suggest that quantitative ultrasonography may be an alternative method to standard DSA for serial follow up of STA grafts.

White-matter functional networks changes in patients with schizophrenia.

Resting-state functional MRI (rsfMRI) is a useful technique for investigating the functional organization of human gray-matter in neuroscience and neuropsychiatry. Nevertheless, most studies have demonstrated the functional connectivity and/or task-related functional activity in the gray-matter. White-matter functional networks have been investigated in healthy subjects. Schizophrenia has been hypothesized to be a brain disorder involving insufficient or ineffective communication associated with white-matter abnormalities. However, previous studies have mainly examined the structural architecture of white-matter using MRI or diffusion tensor imaging and failed to uncover any dysfunctional connectivity within the white-matter on rsfMRI. The current study used rsfMRI to evaluate white-matter functional connectivity in a large cohort of ninety-seven schizophrenia patients and 126 healthy controls. Ten large-scale white-matter networks were identified by a cluster analysis of voxel-based white-matter functional connectivity and classified into superficial, middle and deep layers of networks. Evaluation of the spontaneous oscillation of white-matter networks and the functional connectivity between them showed that patients with schizophrenia had decreased amplitudes of low-frequency oscillation and increased functional connectivity in the superficial perception-motor networks. Additionally, we examined the interactions between white-matter and gray-matter networks. The superficial perception-motor white-matter network had decreased functional connectivity with the cortical perception-motor gray-matter networks. In contrast, the middle and deep white-matter networks had increased functional connectivity with the superficial perception-motor white-matter network and the cortical perception-motor gray-matter network. Thus, we presumed that the disrupted association between the gray-matter and white-matter networks in the perception-motor system may be compensated for through the middle-deep white-matter networks, which may be the foundation of the extensively disrupted connections in schizophrenia.

Discovery of susceptibility loci associated with tuberculosis in Han Chinese.

Genome-wide association studies (GWASs) have revealed the worldwide heterogeneity of genetic factors in tuberculosis (TB) susceptibility. Despite having the third highest global TB burden, no TB-related GWAS has been performed in China. Here, we performed the first three-stage GWAS on TB in the Han Chinese population. In the stage 1 (discovery stage), after quality control, 691 388 SNPs present in 972 TB patients and 1537 controls were retained. After replication on an additional 3460 TB patients and 4862 controls (stages 2 and 3), we identified three significant loci associated with TB, the most significant of which was rs4240897 (logistic regression P = 1.41 × 10-11, odds ratio = 0.79). The aforementioned three SNPs were harbored by MFN2, RGS12 and human leukocyte antigen class II beta chain paralogue encoding genes, all of which are candidate immune genes associated with TB. Our findings provide new insight into the genetic background of TB in the Han Chinese population.

Non-linearity and dynamics of low-voltage electrowetting and dewetting.

As an electrically controllable wetting effect, electrowetting on dielectrics (EWOD) is applied in diverse fields including optics, display technology and lab-on-a-chip systems. For the further development of EWOD applications, the reduction of the operation voltage is an essential issue. Recently, a low-voltage EWOD system with a threshold of 2 V was developed. In its sessile drop configuration, an aqueous electrolyte droplet with microliter scaled volume is actuated on an EWOD electrode in oil. The integration of this low-voltage EWOD system into a multiparameter measurement system enables the non-linearity and dynamics of the EWOD system to be online investigated during electrowetting and dewetting. The non-linearity was characterized by the hysteresis in the droplet deformation and that in the thickness variation of an oil layer, which is entrapped between the droplet and the electrode, in the nm range. The dynamics was evaluated with the characteristic time for the droplet deformation upon voltage jumps. This study of electrowetting and dewetting focuses on the conversion efficiency of the electrical energy in the deformation processes.

Mechanisms of enhanced antiglioma efficacy of polysorbate 80-modified paclitaxel-loaded PLGA nanoparticles by focused ultrasound.

The presence of blood-brain barrier (BBB) greatly limits the availability of drugs and their efficacy against glioma. Focused ultrasound (FUS) can induce transient and local BBB opening for enhanced drug delivery. Here, we developed polysorbate 80-modified paclitaxel-loaded PLGA nanoparticles (PS-80-PTX-NPs, PPNP) and examined the enhanced local delivery into the brain for glioma treatment by combining with FUS. Our result showed PPNP had good stability, fast drug release rate and significant toxicity to glioma cells. Combined with FUS, PPNP showed a stronger BBB permeation efficiency both in the in vitro and in vivo BBB models. Mechanism studies revealed the disrupted tight junction, reduced P-glycoprotein expression and ApoE-dependent PS-80 permeation collectively contribute to the enhanced drug delivery, resulting in significantly stronger antitumour efficacy and longer survival time in the tumour-bearing mice. Our study provided a new strategy to efficiently and locally deliver drugs into the brain to treat glioma.

Frequency Dependence of Low-Voltage Electrowetting Investigated by Impedance Spectroscopy.

An electrowetting-on-dielectric (EWOD) electrode was developed that facilitates the use of low alternating voltages (≤5 VAC). This allows online investigation of the frequency dependence of electrowetting by means of impedance spectroscopy. The EWOD electrode is based on a dielectric bilayer consisting of an anodic tantalum pentoxide (Ta2O5) thin film (d = 59.35 nm) with a high relative permittivity (εd = 26.3) and a self-assembled hydrophobic silane monolayer. The frequency dependence of electrowetting was studied using an aqueous µL-sized sessile droplet on the planar EWOD electrode in oil. Experiments using electrochemical impedance spectroscopy and optical imaging indicate the frequency dependence of all three variables in the Young-Lippmann equation: the voltage drop across the dielectric layers, capacitance per unit area, and contact angle under voltage. The electrowetting behavior induced by AC voltages is shown to be well described by the Young-Lippmann equation for AC applications below a frequency threshold. Moreover, the dielectric layers act as a capacitor and the stored electrostatic potential energy is revealed to only partially contribute to the electrowetting.

Compensatory Mutations of Rifampin Resistance Are Associated with Transmission of Multidrug-Resistant Mycobacterium tuberculosis Beijing Genotype Strains in China.

Mycobacterium tuberculosis can acquire resistance to rifampin (RIF) through mutations in the rpoB gene. This is usually accompanied by a fitness cost, which, however, can be mitigated by secondary mutations in the rpoA or rpoC gene. This study aimed to identify rpoA and rpoC mutations in clinical M. tuberculosis isolates in northern China in order to clarify their role in the transmission of drug-resistant tuberculosis (TB). The study collection included 332 RIF-resistant and 178 RIF-susceptible isolates. The majority of isolates belonged to the Beijing genotype (95.3%, 486/510 isolates), and no mutation was found in rpoA or rpoC of the non-Beijing genotype strains. Among the Beijing genotype strains, 27.8% (89/320) of RIF-resistant isolates harbored nonsynonymous mutations in the rpoA (n = 6) or rpoC (n = 83) gene. The proportion of rpoC mutations was significantly higher in new cases (P = 0.023) and in strains with the rpoB S531L mutation (P < 0.001). In addition, multidrug-resistant (MDR) strains with rpoC mutations were significantly associated with 24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat clustering (P = 0.016). In summary, we believe that these findings indirectly suggest an epistatic interaction of particular mutations related to RIF resistance and strain fitness and, consequently, the role of such mutations in the spread of MDR M. tuberculosis strains.

Prevalence and molecular characteristics of drug-resistant Mycobacterium tuberculosis in Beijing, China: 2006 versus 2012.

BACKGROUND: As the epidemic of MDR-TB and XDR-TB becomes increasingly severe, it is important to determine the clinical characteristics and molecular epidemiology of MDR-TB and XDR-TB. Recently, many studies have shown that clinical features and molecular characteristics of drug-resistant strains vary in different geographical areas, however, further information is needed to assess the dynamic evolution of drug-resistant TB. Comparative studies between different time periods are necessary to elucidate the development of drug-resistant TB. RESULTS: A total of 255 and 537 strains were collected from Beijing Chest Hospital in 2006 and in 2012, respectively. Drug-resistance rates and mutations associated with resistance to first-line anti-tuberculosis (TB) drugs were compared. The overall rate of drug resistance among strains of TB in 2012 was 54.4 %, significantly higher than that in 2006 (34.9 %, P < 0.001). Rates of resistance to each first-line drug (isoniazid, rifampicin, streptomycin and ethambutol) and to second-line drug ofloxacin increased significantly from 2006 to 2012. The overall MDR rate also increased significantly from 2006 (14.9 %) to 2012 (27.0 %). The rate of MDR increased significantly between these two time periods in previously treated cases (P = 0.023) but not in new cases (P = 0.073), and the rate of XDR was similar in new cases at the two time periods, but was marginally higher in 2012 in previously treated cases (P = 0.056). Previous treatment was found to be a risk factor for drug-resistant TB, especially for MDR-TB. In addition, the proportion of drug resistant isolates in which katG, the mabA-inhA promoter, oxyR-ahpC intergenic region, rpoB, rpsL, and embB were mutated was similar in 2006 and 2012, however patterns of mutation in these loci were more diverse in 2012 compared to 2006. CONCLUSIONS: Our data suggests that the prevalence of drug resistant TB remains high in Beijing, China, and that increasing rates of resistance in M. tuberculosis to all anti-TB drugs should be considered when choosing an optimal anti-TB regimen. Moreover, acquired multi-drug resistance may play a primary role in the MDR-TB epidemic in Beijing, China. Consequently, this highlights the importance of an earlier start to effective and supervised treatment in order to reduce the burden of retreatment.

Response of heterogeneous cancer cells on targeted nanoparticles.

Heterogenous cancer cells possess cancer multidrug resistance (MDR) due to their relative quiescence and ABC-transporter expression. Heterogenous cancer cells can be detected by an Rh123 exclusion assay for identifying Rh123low population. In the present study, we fabricated targeted nanoparticles entrapped with Rh123 (Rh123 NPs) to investigate the effect of these targeted nanoparticles on an Rh123low population. The Rh123low population stained by Rh123 NPs exhibited similar heterogeneity to that stained by Rh123. In addition, the ABC-transporters did not contribute to the uptake of Rh123 or Rh123 NPs. Interestingly, ABC-transporters in the Rh123low population stained by Rh123 were possibly responsible for Rh123 efflux, while Rh123 NPs were not susceptible to ABC-transporters in the Rh123low population. It is plausible that the synergistic effect of NPs caused a targeted and endocytic effect which promoted the cellular uptake of Rh123 NPs, and the targeted effect played a more important role.