[Comparison of the microbiota diversity between autogenous and anautogenous Culex pipiens pallens]

OBJECTIVE

To investigate the microbiota composition and diversity between autogenous and anautogenous Culex pipiens pallens, so as to provide insights into unraveling the pathogenesis of autogeny in Cx. pipiens pallens.

METHODS

Autogenous and anautogenous adult Cx. pipiens pallens samples were collected at 25 ℃, and the hypervariable regions of the microbial 16S ribosomal RNA (16S rRNA) gene was sequenced on the Illumina NovaSeq 6000 sequencing platform. The microbiota abundance and diversity were evaluated using the alpha diversity index, and the difference in the microbiota structure was examined using the beta diversity index. The microbiota with significant differences in the abundance between autogenous and anautogenous adult Cx. pipiens pallens samples was identified using the linear discriminant analysis effect size (LEfSe).

RESULTS

The microbiota in autogenous and anautogenous Cx. pipiens pallens samples belonged to 18 phyla, 28 classes, 70 orders, 113 families, and 170 genera, and the dominant phyla included Proteobacteria, Bacteroidetes, and so on. At the genus level, Wolbachia was a common dominant genus, and the relative abundance was (77.6 ± 11.3)% in autogenous Cx. pipiens pallens samples and (47.5 ± 8.5)% in anautogenous mosquito samples, while Faecalibaculum (0.4% ± 0.1%), Dubosiella (0.5% ± 0.0%) and Massilia (0.5% ± 0.1%) were specific species in autogenous Cx. pipiens pallens samples. Alpha diversity analysis showed that higher Chao1 index and ACE index in autogenous Cx. pipiens pallens samples than in anautogenous samples (both P values > 0.05), and lower Shannon index (P > 0.05) and Simpson index (P < 0.05) in autogenous Cx. pipiens pallens samples than in anautogenous samples. LEfSe analysis showed a total of 48 significantly different taxa between autogenous and anautogenous Cx. pipiens pallens samples (all P values < 0.05).

CONCLUSIONS

There is a significant difference in the microbiota diversity between autogenous and anautogenous Cx. pipiens pallens.

A Tandem-Locked Chemiluminescent Probe for Imaging of Tumor-Associated Macrophage Polarization

Tumor-associated macrophages (TAMs) play a role in both pro- and anti-tumor functions; and the targeted polarization from M2 to M1 TAMs has become an effective therapy option. Although detection of M1 TAMs is imperative to assess cancer immunotherapeutic efficacy, existing optical probes suffer from shallow tissue penetration depth and poor specificity toward M1 TAMs. Herein, we report a tandem-locked NIR chemiluminescent (CL) probe for specific detection of M1 TAMs. Through a combined molecular engineering approach via both atomic alternation and introduction of electron-withdrawing groups, near-infrared (NIR) chemiluminophores are screened out to possess record-long emission (over 800 nm), record-high CL quantum yield (2.7 % einstein/mol), and prolonged half-life (7.7 h). Based on an ideal chemiluminophore, the tandem-locked probe (DPDGN) is developed to only activate CL signal in the presence of both tumour (γ-glutamyl transpeptidase) and M1 macrophage biomarkers (nitric oxide). Such a tandem-lock design ensures its high specificity towards M1 macrophages in the tumor microenvironment over those in normal tissues or peripheral blood. Thus, DPDGN permits noninvasive imaging and tracking of M1 TAM in the tumor of living mice during R837 treatment, showing a good correlation with ex vivo methods. This study not only reports a new molecular approach towards highly efficient chemiluminophores but also reveals the first tandem-locked CL probes for enhanced imaging specificity.

Ingestible Artificial Urinary Biomarker Probes for Urine Test of Gastrointestinal Cancer

Although colorectal cancer diagnosed at early stage shows high curability, methods simultaneously possessing point-of-care testing ability and high sensitivity are limited. Here, we present an orally deliverable biomarker-activatable probe (termed as HATS) for early detection of orthotopic tumor via remote urinalysis. To enable its oral delivery to colon, HATS is designed to have remarkable resistance to acidity and digestive enzymes in the stomach and small intestine, and negligible intestinal absorption. Upon reaction with a cancer biomarker in colon segment, HATS releases a small fragment of tetrazine that can transverse the intestinal barrier, enter blood circulation, and ultimately undergo renal clearance to urine. Subsequently, the urinary tetrazine fragment is detected by bioorthogonal reaction with trans-cyclooctene-caged resorufin (TCO-Reso) to afford a rapid and specific fluorescence enhancement of TCO-Reso. Such signal readout is correlated with the urinary tetrazine concentration and thus measures the level of cancer biomarker in colon. HATS-based optical urinalysis detects orthotopic colon tumor two weeks earlier than clinical serological test and can be developed to point-of-care paper test. Thereby, HATS-based urinalysis provides a non-invasive and sensitive approach for cancer screening at low-resource settings. This article is protected by copyright. All rights reserved.

Near-Infrared Chemiluminescence Imaging of Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) has a high prevalence but is poorly managed for cancer patients due to the lack of reliable and sensitive diagnostic techniques. Molecular optical imaging can provide a noninvasive way for real-time monitoring of CIPN; However, this is not reported, likely due to the absence of optical probes capable of imaging deep into the spinal canal and possessing sufficient sensitivity for minimal dosage through local injection into the dorsal root ganglia. Herein, a near-infrared (NIR) chemiluminophore (MPBD) with a chemiluminescence quantum yield higher than other reported probes is synthesized and a NIR activatable chemiluminescent probe (CalCL) is developed for in vivo imaging of CIPN. CalCL is constructed by caging MPBD with calpain-cleavable peptide moiety while conjugating polyethylene glycol chain to endow water solubility. Due to the deep-tissue penetration of chemiluminescence and specific turn-on response of CalCL toward calpain (a hallmark of CIPN), it allows for sensitive detection of paclitaxel-mediated CIPN in living mice, which is unattainable by fluorescence imaging. This study thus not only develops a highly efficient chemiluminescent probe, but also presents the first optical imaging approach toward high-throughput screening of neurotoxic drugs.

[Epidemiologic characteristics and drug resistance of isolated from blood culture escherichia coli in a hospital in Qinghai Province from 2016 to 2022]

Objective: To explore the drug resistance of Isolated From Blood Culture Escherichia coli (E. coli) in a hospital in Qinghai over the past seven years, to evaluate the ability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to analyze the homologous origin of E. coli, and to establish a protein fingerprint library to match with it, adjuvant clinical experience medication so as to provide the basis for the prevention and control of hospital-acquired infections. Methods: Retrospective analysis of blood cultures sent to hospitals from January 2016 to December 2022. Drug resistance and resistance changes in E. coli.A total of 1 841 E. coli strains were isolated from Qinghai Provincial People's Hospital from January 2016 to December 2022; all strains were identified by MALDI-TOF MS, and the VITEK2.0 drug sensitivity analyzer was applied for drug sensitivity analysis of the strains, and the mass spectrometry homology analysis and self-constructed protein fingerprint library were carried out by MALDI-Biotyper software; the protein fingerprint library was built by using WHONET5.6 software was used to statistically analyze the drug sensitivity results, SPSS23.0 software was used to analyze the relationship between fingerprint typing and drug sensitivity, and the χ2 test was used for intergroup comparisons. Results: A total of 1 841 strains of E. coli were detected in 4 582 positive blood culture specimens from January 2016 to December 2022, with a detection rate of 40.17%; the resistance rate of E. coli from blood sources to piperacillin/tazobactam and ceftriaxone was on the rise, and it was slightly decreased to cefepime, amikacin, levofloxacin, and sulfamethoxazole, and there was not much change to the rest of the drugs; After MALDI-Biotyper clustering analysis, the 1841 E. coli strains from Isolated From Blood Culture were classified into two major clusters and five subtypes, of which type Ⅰa1 accounted for about 40%, type Ⅰa2 accounted for about 2.7%, type Ⅰb accounted for about 3.8, type Ⅱa accounted for about 46%, and type Ⅱb accounted for about 7.5%. The detection rate of type Ⅰa1 E. coli was higher in general surgery (50.45%) and emergency surgery (50.92%), and the detection rate of type Ⅰb E. coli was higher in emergency medicine(10.05%)than in other departments. The drug sensitivity results of different subtypes were compared with each other, the resistance rate of type Ⅰa1 E. coli to cefepime was 21.3% higher than that of the remaining four types, and the difference was statistically significant (χ2=37.74,P=0.000); the resistance rate of type Ⅱ E. coli(>60%) to sulfamethoxazole was higher than that of type Ⅰ (<60%) as a whole, and the difference was statistically significant (χ2=15.248,P=0.004); and a preliminary database of homologous protein fingerprints of E. coli has been established E. coli homologous protein fingerprint library and validated. The drug susceptibility results of 1 288 E. coli strains in the validation set were statistically analyzed and compared with those in the training set. There was no significant difference(P>0.05). Conclusion: In recent years, the resistance rate of E. coli isolated from a hospital in Qinghai province to piperacillin/Tazobactam, cefepime, amicacin and other antibiotics has changed greatly. A fingerprint database of E. coli homologous protein was established, and it was found that the drug sensitivity data of E. coli were different among different fingerprint types. According to drug sensitivity, drug use could assist clinical experience and provide evidence for prevention and control of hospital illness.

Prognostic value of plaque volume combined with CT fractional flow reserve in patients with suspected coronary artery disease

AIM

To investigate the prognostic value of quantitative plaque volume on coronary computed tomography (CT) angiography (CTA) combined with CT fractional flow reserve (CT-FFR) for major adverse cardiac events (MACE) in suspected coronary artery disease (CAD) patients.

MATERIALS AND METHODS

Patients who underwent coronary CTA with clinically suspected CAD were enrolled retrospectively in this study. Patients' baseline, Framingham Risk Score (FRS), coronary CTA plaque assessment, and CT-FFR were analysed retrospectively. Study outcomes included rehospitalisation and MACE (ST-segment elevation myocardial infarction, unstable angina, or non-ST-segment elevation myocardial infarction, revascularisation, and cardiac death).

RESULTS

There were 251 patients in the study, with a follow-up period of 1-6.58 years. Mean age was 61.16 ± 10.45 years and 146 (58%) patients were male. Higher CT-adapted Leaman score and quantitative plaque volume were found in patients with FRS >0.2 regardless of categorical or continuous variables. Coronary scores, quantitative plaque parameters, and CT-FFR were associated with MACE and rehospitalisation in univariate analysis. In model 1, CT-FFR was associated with MACE in multivariate Cox analysis when adjusted for FRS and CT-adapted Leaman score. Quantitative plaque parameters including calcified plaque volume, fibro-fatty plaque volume, low-attenuation plaque volume, non-calcified plaque volume, and total plaque volume were significantly associated with MACE and improved overall prognostic performance in a model adjusted for CT-FFR.

CONCLUSION

Additional quantitative plaque volume and CT-FFR further improve the predictive incremental value based on risk factor scores for prognostic prediction in patients. Adding quantitative plaque volume combined with CT-FFR analysis to anatomical and clinical assessment will be further beneficial to predict patients' prognosis of MACE.

A Semiconducting Iron-Chelating Nano-immunomodulator for Specific and Sensitized Sono-metallo-immunotherapy of Cancer

Sono-immunotherapy holds great potential for deep tumor inhibition; however, smart sono-therapeutic agents to simultaneously eliminate 'domestic' tumor cells and regulate the 'community' tumor immune microenvironment have rarely been developed. Herein, we report a spatiotemporally controllable semiconducting iron-chelated nano-metallomodulator (SINM) for hypersensitive sono-metallo-immunotherapy of cancer. SINM consists of a semiconducting polymer (SP) backbone chelating iron ions (Fe3+ ) with thiophene-based Schiff base structure, and a hydrophilic side chain. Upon accumulation in tumors after systemic administration, SINM specifically arouses ferroptosis and M1 macrophage polarization due to its response toward the tumor redox environment; meanwhile, the chelation of Fe3+ enhances the sono-sensitizing effect of SPs, leading to enhanced generation of reactive oxygen species for immunogenic cell death. Such combined sonodynamic metallo-immunotherapy of SINM efficiently ablates deep tumor and spatiotemporally regulates immunophenotypes.

[Treatment of patent ductus arteriosus in very preterm infants in China]

Objective: To describe the current status and trends in the treatment of patent ductus arteriosus (PDA) among very preterm infants (VPI) admitted to the neonatal intensive care units (NICU) of the Chinese Neonatal Network (CHNN) from 2019 to 2021, and to compare the differences in PDA treatment among these units. Methods: This was a cross-sectional study based on the CHNN VPI cohort, all of 22 525 VPI (gestational age<32 weeks) admitted to 79 tertiary NICU within 3 days of age from 2019 to 2021 were included. The overall PDA treatment rates were calculated, as well as the rates of infants with different gestational ages (≤26, 27-28, 29-31 weeks), and pharmacological and surgical treatments were described. PDA was defined as those diagnosed by echocardiography during hospitalization. The PDA treatment rate was defined as the number of VPI who had received medication treatment and (or) surgical ligation of PDA divided by the number of all VPI. Logistic regression was used to investigate the changes in PDA treatment rates over the 3 years and the differences between gestational age groups. A multivariate Logistic regression model was constructed to compute the standardized ratio (SR) of PDA treatment across different units, to compare the rates after adjusting for population characteristics. Results: A total of 22 525 VPI were included in the study, with a gestational age of 30.0 (28.6, 31.0) weeks and birth weight of 1 310 (1 100, 1 540) g; 56.0% (12 615) of them were male. PDA was diagnosed by echocardiography in 49.7% (11 186/22 525) of all VPI, and the overall PDA treatment rate was 16.8% (3 795/22 525). Of 3 762 VPI who received medication treatment, the main first-line medication used was ibuprofen (93.4% (3 515/3 762)) and the postnatal day of first medication treatment was 6 (4, 10) days of age; 59.3% (2 231/3 762) of the VPI had been weaned from invasive respiratory support during the first medication treatment, and 82.2% (3 092/3 762) of the infants received only one course of medication treatment. A total of 143 VPI underwent surgery, which was conducted on 32 (22, 46) days of age. Over the 3 years from 2019 to 2021, there was no significant change in the PDA treatment rate in these VPI (P=0.650). The PDA treatment rate decreased with increasing gestational age (P<0.001). The PDA treatment rates for VPI with gestational age ≤26, 27-28, and 29-31 weeks were 39.6% (688/1 737), 25.9% (1 319/5 098), and 11.4% (1 788/15 690), respectively. There were 61 units having a total number of VPI≥100 cases, and their rates of PDA treatment were 0 (0/116)-47.4% (376/793). After adjusting for population characteristics, the range of standardized ratios for PDA treatment in the 61 units was 0 (95%CI 0-0.3) to 3.4 (95%CI 3.1-3.8). Conclusions: From 2019 to 2021, compared to the peers in developed countries, VPI in CHNN NICU had a different PDA treatment rate; specifically, the VPI with small birth gestational age had a lower treatment rate, while the VPI with large birth gestational age had a higher rate. There are significant differences in PDA treatment rates among different units.

Artificial Urinary Biomarkers for Early Diagnosis of Acute Renal Allograft Rejection

Acute renal allograft rejection (ARAR) after kidney transplantation associated with reduced graft survival and eventual graft failure is poorly diagnosed in hospitals. Here, we report the development of Artificial bioMarker Probes (AMPros) for sensitive urinalysis of ARAR in murine models. AMPros spontaneously go to the kidneys after systemic administration, specifically react with the prodromal immune biomarkers to activate their near-infrared fluorescence signals to report cell-mediated rejection, and efficiently undergo renal excretion into urine. Thus, AMPros enable convenient optical urinalysis that detects ARAR prior to histological manifestation of rejection, which is also earlier than current diagnostic methods measuring proinflammatory cytokines and peripheral blood lymphocyte mRNAs. Due to the high kidney specificity, AMPros-based urinalysis discriminates allograft rejection against other non-alloimmune specific diseases, which is unattainable by measurement of serological biomarkers. Such a noninvasive and sensitive urine test holds great promise in continuous monitoring of renal allograft conditions at low resource settings for timely clinical interventions.

A Tandem-Locked Fluorescent NETosis Reporter for the Prognosis Assessment of Cancer Immunotherapy

NETosis, the peculiar type of neutrophil death, plays important roles in pro-tumorigenic functions and inhibits cancer immunotherapy. Non-invasive real-time imaging is thus imperative for prognosis of cancer immunotherapy yet remains challenging. Herein, we report a Tandem-locked NETosis Reporter 1 (TNR1 ) that activates fluorescence signals only in the presence of both neutrophil elastase (NE) and cathepsin G (CTSG) for the specific imaging of NETosis. In the aspect of molecular design, the sequence of biomarker-specific tandem peptide blocks can largely affect the detection specificity towards NETosis. In live cell imaging, the tandem-locked design allows TNR1 to differentiate NETosis from neutrophil activation, while single-locked reporters fail to do so. The near-infrared signals from activated TNR1 in tumor from living mice were consistent with the intratumoral NETosis levels from histological results. Moreover, the near-infrared signals from activated TNR1 negatively correlated with tumor inhibition effect after immunotherapy, thereby providing prognosis for cancer immunotherapy. Thus, our study not only demonstrates the first sensitive optical reporter for noninvasive monitoring of NETosis levels and evaluation of cancer immunotherapeutic efficacy in tumor-bearing living mice, but also proposes a generic approach for tandem-locked probe design.

Activatable near-infrared probes for the detection of specific populations of tumour-infiltrating leukocytes in vivo and in urine

Tracking the immune microenvironment of tumours is essential for understanding the mechanisms behind the effectiveness of cancer immunotherapies. Molecular imaging of tumour-infiltrating leukocytes (TILs) can be used to non-invasively monitor the tumour immune microenvironment, but current imaging agents do not distinguish TILs from leukocytes resident in other tissues. Here we report a library of activatable molecular probes for the imaging, via near-infrared fluorescence, of specific TILs (including M1 macrophages, cytotoxic T lymphocytes and neutrophils) in vivo in real time and also via excreted urine, owing to the probes' renal clearance. The fluorescence of the probes is activated only in the presence of both tumour and leukocyte biomarkers, which allows for the imaging of populations of specific TILs in mouse models of cancers with sensitivities and specificities similar to those achieved via flow-cytometric analyses of biopsied tumour tissues. We also show that the probes enable the non-invasive evaluation of the immunogenicity of different tumours, the dynamic monitoring of responses to immunotherapies and the accurate prediction of tumour growth under various treatments.

A Dual-Locked Tandem Fluorescent Probe for Imaging of Pyroptosis in Cancer Chemo-Immunotherapy

Real-time imaging of programmed cancer cell death (PCD) is imperative to monitor cancer therapeutic efficacy and tailor therapeutic regimens; however, specific in vivo detection of intratumoral pyroptosis remains challenging. Herein, a dual-locked and tandem activatable probe (DTAP) is reported for near-infrared fluorescence (NIRF) imaging of intratumoral pyroptosis during cancer chemo-immunotherapy in living mice. The probe comprises a hemicyanine dye dual-locked with an enzyme-responsive moiety that can be tandemly cleaved by pyroptosis-related biomarker (Caspase-1) and cancer biomarker (GGT) to turn on its NIRF signal. As pyroptosis plays a vital role in triggering anti-tumor immune responses, the activated signal of DTAP correlates well with the population of tumor-infiltrating cytotoxic T lymphocytes and tumor growth inhibition, consequently permitting the prediction of cancer therapeutic efficacy. This study also provides a non-invasive technique to study the regulatory mechanism of pyroptosis in cancer therapy and to optimize cancer chemo-immunotherapies for precision medicine.

[Correlation of extracellular enzymes activity of Candida glabrata clinical isolates with in vivo pathogenicity in Galleria mellonella larvae]

Objective: To explore the relationship between extracellular enzymes activity and virulence of Candida glabrata clinical isolates based on the infection model of Galleria mellonella larvae. Methods: Using experimental research methods, 71 strains of non-repetitive Candida glabrata were collected from Qinghai Provincial People's Hospital from June 2021 to January 2022. Bovine serum protein agar medium, egg yolk agar medium, sheep blood agar medium, Tween-80 agar medium and triglyceride agar medium were used to detect the aspartyl protease activity, phospholipase activity, hemolysis activity, esterase activity and lipase activity of Candida glabrata. Median lethal concentration (LC₅₀) was calculated by using 1.25×10⁸ CFU/ml,2.50×10⁸ CFU/ml,3.75×10⁸ CFU/ml,5.00×10⁸ CFU/ml suspension of Candida glabrata ATCC2001 to infect Galleria mellonella larvae. Histopathological and etiological analysis was performed to determine whether the infection model was successfully established. The clinical isolates of Candida glabrata were configured to infect Galleria mellonella larvae with LC₅₀ concentration to detect the pathogenicity of Galleria mellonella larvae.Spearman test or Pearson test were used to analyze the correlation between the extracellular enzyme activity of Candida glabrata clinical isolates and the pathogenicity of Galleria mellonella larvae. Results: 71 strains of Candida glabrata isolated clinically were detected to have low hemolytic activity after 2 days of culture. Aspartyl protease was detected after 4 days of culture, among which 7 strains (9.86%), 19 strains (26.76%) and 45 strains (63.38%) showed low, medium and high aspartyl protease activity. After 7 days of culture, 71 strains did not detect phospholipase, esterase and lipase activities. Candida glabrata on Galleria mellonella larvae of LC₅₀=2.5×10⁸ CFU/ml Fungal spore were found in the intestinal tissue pathological section of Galleria mellonella larvae in the experimental group, and Candida glabrata was identified by the microbial Mass Spectrometry after culture, while no fungi were found in the pathological section and culture of the control group. Spearman test shows that, there was a linear positive correlation between aspartyl protease activity and the survival rate of Galleria mellonella larvae (r = 0.73, P<0.01), the difference was statistically significant.Pearson test shows that, there was no significant linear relationship between hemolytic activity and survival rate of Galleria mellonella larvae (r = 0.16, P = 0.34), the difference was not statistically significant. Conclusion: The clinical isolates of Candida glabrata in this study had aspartyl protease activity and low hemolytic activity, but no phospholipase, esterase and lipase activity. The activity of aspartyl aspartyl protease of Candida glabrata was positively correlated with the pathogenicity of Galleria mellonella larvae.

Smart Nano-PROTACs Reprogram Tumor Microenvironment for Activatable Photo-metabolic Cancer Immunotherapy

Protease inhibitors can modulate intratumoral metabolic processes to reprogram the immunosuppressive tumor microenvironment (TME), which however suffer from the limited efficacy and off-targeted side effects. We report smart nano-proteolysis targeting chimeras (nano-PROTACs) with phototherapeutic ablation and cancer-specific protein degradation to reprogram the TME for photo-metabolic cancer immunotherapy. This nano-PROTAC has a semiconducting polymer backbone linked with a cyclooxygenase 1/2 (COX-1/2)-targeting PROTAC peptide (CPP) via a cathepsin B (CatB)-cleavable segment. CPP can be activated by the tumor-overexpressed CatB to induce the degradation of COX-1/2 via the ubiquitin-proteasome system. The persistent degradation of COX-1/2 depletes their metabolite prostaglandin E₂ which is responsible for activation of immune suppressor cells. Such a smart PROTAC strategy synergized with phototherapy specifically reprograms the immunosuppressive TME and reinvigorates antitumor immunity.

[Effects and mechanisms of allogeneic epidermal stem cells on the survival of allogeneic full-thickness skin grafts in nude mice with full-thickness skin defect wounds]

Objective: To investigate the effects and mechanisms of allogeneic epidermal stem cells (ESCs) on the survival of allogeneic full-thickness skin grafts in nude mice with full-thickness skin defect wounds. Methods: Experimental research methods were applied. Primary ESCs that appeared paving stone-like after being cultured for 7 d were obtained by enzymatic digestion method from one 4-week-old male BALB/c-NU nude mouse (the same strain, age, and sex below). The cells of third passage were identified by flow cytometry to positively express ESC marker CD44 and negatively express CD45, meanwhile, the positive expression of ESC markers of p63 and integrin 6α, and negative expression of CD71 were identified by immunofluorescence method. The ESCs of third passage in the logarithmic growth phase were used for the following experiments. Twenty-six nude mice were equally divided into phosphate buffered saline (PBS) group and ESCs group according to the random number table. A full-thickness skin defect wound was made on the back of each nude mouse, and then the wounds of the two groups were sprayed with equal volumes of PBS and ESCs, respectively. The wounds were transplanted with full-thickness skin grafts cut from the backs of 4 other nude mice. Each ten nude mice from the two groups were selected, the wound healing and skin survival on post surgery day (PSD) 0 (immediately), 3, 7, 14, and 21 were observed, and the survival ratio and shrinkage rate of skin grafts on PSD 3, 7, 14, and 21 were calculated (the number of sample was the number of surviving skin grafts at each time point); the blood perfusion in the skin grafts on PSD 3, 7, and 14 was detected by the laser speckle blood flow imager, and the blood flow ratio of nude mice skin grafts in ESCs group to PBS group at each time point was calculated (the number of sample was the pair number of surviving skin grafts in group pairing at each time point). The skin graft tissue of each 3 nude mice remained in the two groups were collected on PSD 7, and the mRNA expressions and protein expressions of tumor necrosis factor α (TNF-α), interleukin 8 (IL-8), IL-10, type Ⅰ collagen, type Ⅲ collagen, and matrix metalloproteinase 9 (MMP-9) in the tissue were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. Data were statistically analyzed with Log-rank test, analysis of variance for repeated measurement, one-way analysis of variance, independent sample t test, and Bonferroni correction. Results: Taking the condition on PSD 0 as a reference, the wounds of nude mice in the two groups healed gradually on PSD 3, 7, 14, and 21, and the shrinkage of skin grafts was gradually obvious. Among them, the shrinkage healing of wound of nude mice in PBS group was more significant than that in ESCs group. On PSD 3, the skin graft of 1 nude mouse failed in ESCs group, while the skin graft of 3 nude mice failed in PBS group. On PSD 7, the skin graft of another nude mouse failed in PBS group. The survival ratio of skin grafts of nude mice in the two groups was similar on PSD 3, 7, 14, and 21 (P>0.05). On PSD 3, 7, 14, and 21, the shrinkage rates of skin grafts of nude mice in ESCs group were (9.2±0.4)%, (19.7±1.2)%, (53.6±3.5)%, and (62.2±5.1)%, respectively, which was significantly lower than (11.0±0.9)%, (47.8±2.8)%, (86.1±7.1)%, and (89.7±9.0)% in PBS group (t=5.719, 26.650, 11.940, 7.617, P<0.01). On PSD 3, 7, and 14, blood perfusion signals were observed in the skin grafts of nude mice in the two groups. The average blood perfusion ratios of the skin grafts of nude mice in ESCs group to PBS group were greater than 1, and there was no statistically significant difference in the overall comparison of 3 time points (P>0.05). On PSD 7, compared with those of PBS group, the mRNA and protein expressions of TNF-α, IL-8, type Ⅰ collagen, and type Ⅲ collagen in the skin graft tissue of nude mice in ESCs group were significantly reduced, while the mRNA and protein expressions of IL-10 and MMP-9 in the skin graft tissue of nude mice in ESCs group were significantly increased (in mRNA comparison, t=2.823, 2.934, 2.845, 2.860, 3.877, 2.916, P<0.05). Conclusions: Allogeneic ESCs can reduce the shrinkage of allogeneic full-thickness skin grafts transplanted on full-thickness skin defect wounds in nude mice, promote the formation of new blood vessels between the skin graft and the wound, reduce inflammation and collagen protein expression, and promote the expression of MMP-9, thus improving the survival quality of skin grafts.

Renal-Clearable Molecular Probe for Near-Infrared Fluorescence Imaging and Urinalysis of SARS-CoV-2

Despite the importance of rapid and accurate detection of SARS-CoV-2 in controlling the COVID-19 pandemic, current diagnostic methods are static and unable to distinguish between viable/nonviable virus or directly reflect viral replication activity. Real-time imaging of protease activity specific to SARS-CoV-2 can overcome these issues but remains lacking. Herein, we report a near-infrared fluorescence (NIRF) activatable molecular probe (SARS-CyCD) for detection of SARS-CoV-2 protease in living mice. The probe comprises a hemicyanine fluorophore caged with a protease peptide substrate and a cyclodextrin unit, which function as an NIRF signaling moiety and a renal-clearable enabler, respectively. The peptide substrate of SARS-CyCD can be specifically cleaved by SARS-CoV-2 main protease (Mpro), resulting in NIRF signal activation and liberation of the renal-clearable fluorescent fragment (CyCD). Such a design not only allows sensitive detection of Mpro in the lungs of living mice after intratracheal administration but also permits optical urinalysis of SARS-CoV-2 infection. Thus, this study presents an in vivo sensor that holds potential in preclinical high-throughput drug screening and clinical diagnostics for respiratory viral infections.

Renal-Clearable Molecular Probe for Near-Infrared Fluorescence Imaging and Urinalysis of SARS-CoV-2

Despite the importance of rapid and accurate detection of SARS-CoV-2 in controlling the COVID-19 pandemic, current diagnostic methods are static and unable to distinguish between viable/nonviable virus or directly reflect viral replication activity. Real-time imaging of protease activity specific to SARS-CoV-2 can overcome these issues but remains lacking. Herein, we report a near-infrared fluorescence (NIRF) activatable molecular probe (SARS-CyCD) for detection of SARS-CoV-2 protease in living mice. The probe comprises a hemicyanine fluorophore caged with a protease peptide substrate and a cyclodextrin unit, which function as an NIRF signaling moiety and a renal-clearable enabler, respectively. The peptide substrate of SARS-CyCD can be specifically cleaved by SARS-CoV-2 main protease (M^pro), resulting in NIRF signal activation and liberation of the renal-clearable fluorescent fragment (CyCD). Such a design not only allows sensitive detection of M^pro in the lungs of living mice after intratracheal administration but also permits optical urinalysis of SARS-CoV-2 infection. Thus, this study presents an in vivo sensor that holds potential in preclinical high-throughput drug screening and clinical diagnostics for respiratory viral infections.

Charge-Reversal Polymer Nano-modulators for Photodynamic Immunotherapy of Cancer

Nanomedicine can regulate the balance between cytotoxic T lymphocytes (CTLs) and suppressive regulatory T lymphocytes (Tregs), which however has been rarely exploited for cancer immunotherapy. We report a charge-reversal polymer nano-modulator (SP_DMC N) activated by tumor microenvironment (TME) for photodynamic immunotherapy of cancer. SP_DMC N is constructed by conjugating an immunomodulator (demethylcantharidin, DMC) to the side chains of a photodynamic polymer via an acid-liable linker. The negative charge of SP_DMC N ensures its high stability in blood circulation and ideal tumor accumulation; exposure to acidic TME reverses its surface charge to positive, enhancing tumor penetration and locally releasing DMC. Upon near-infrared photoirradiation, SP_DMC N generates singlet oxygen to ablate tumors and promote maturation of dendritic cells. Released DMC inhibits protein phosphatase 2 (PP2A) activity and decreases Tregs differentiation. Such combinational action induces a sharp increase in CTL/Treg ratio in TME and effectively inhibits both primary and distant tumors in living mice.

Granzyme B PET Imaging of Immune Checkpoint Inhibitor Combinations in Colon Cancer Phenotypes

PURPOSE

Immune checkpoint inhibitor (ICI) monotherapy and combination regimens are being actively pursued as strategies to improve durable response rates in cancer patients. However, the biology surrounding combination therapies is not well understood and may increase the likelihood of immune-mediated adverse events. Accurate stratification of ICI response by non-invasive PET imaging may help ensure safe therapy management across a wide number of cancer phenotypes.

PROCEDURES

We have assessed the ability of a fluorine-labelled peptide, [18F]AlF-mNOTA-GZP, targeting granzyme B, to stratify ICI response in two syngeneic models of colon cancer, CT26 and MC38. In vivo tumour uptake of [18F]AlF-mNOTA-GZP following ICI monotherapy, or in combination with PD-1 was characterised and correlated with changes in tumour-associated immune cell populations.

RESULTS

[18F]AlF-mNOTA-GZP showed good predictive ability and correlated well with changes in tumour-associated T cells, especially CD8+ T cells; however, overall uptake and response to monotherapy or combination therapies was very different in the CT26 and MC38 tumours, likely due to the immunostimulatory environment imbued by the MSI-high phenotype in MC38 tumours.

CONCLUSIONS

[18F]AlF-mNOTA-GZP uptake correlates well with changes in CD8+ T cell populations and is able to stratify tumour response to a range of ICIs administered as monotherapies or in combination. However, tracer uptake can be significantly affected by preexisting phenotypic abnormalities potentially confusing data interpretation.

0007 Daytime Sleep in Night Shift Workers: Quantifying the Role of Circadian Misalignment

Introduction

Circadian misalignment is commonly cited as a culprit of daytime sleep disturbances in night shift workers; however, the specific impact and magnitude that circadian misalignment has on daytime sleep has not been well-characterized in larger samples of night shift workers.

Methods

Participants included fixed-night shift workers (n=52, ages 18–50) who completed an 8-hour daytime polysomnography (PSG) in the lab following a night shift. Measures of sleep disturbances included: difficulty falling asleep (sleep onset latency [SOL], latency to persistent sleep [LPS]), difficulty staying asleep (sleep efficiency [SE], wake after sleep onset [WASO]), and sleep duration (total sleep time [TST]). Melatonin samples were collected hourly for 24 hours under dim light (&lt;10 lux) and used to determine dim light melatonin offset (DLMOff). Circadian misalignment (CM) was calculated as the time difference between bedtime and DLMOff (higher values represented sleeping after DLMOff), and correlated with PSG sleep variables.

Results

CM was significantly associated with difficulty staying asleep (WASO: r=0.48, p&lt;0.001; SE: r=-0.45, p&lt;0.001), and sleep duration (TST: r=-0.38, p&lt;0.01). Specifically, every 3 hours of CM on average added 19.2 minutes of WASO and reduced TST by 15 minutes. In contrast, CM was not significantly correlated with sleep onset difficulties (SOL: r=-0.27; LPS: r=-0.02).

Conclusion

These data suggest that circadian misalignment in shift workers may be a better predictor of difficulties staying asleep and sleep duration during the day relative to difficulties falling asleep. Because longer work hours (10–12 hours) are common in night shift worker, it may be that sleep initiation difficulties associated with circadian misalignment is masked by elevated fatigue or an increased homeostatic drive from prolonged wakefulness. These results may help guide decisions about the magnitude of phase shifts required (e.g., with light therapy) for the desired improvement in daytime sleep.

Support

Support for this study was provided to PC by the NHLBI (K23HL138166)

0006 The Role of Stress in Sleep in Night Shift Workers: Going Beyond Circadian Misalignment

Introduction

Despite a growing need for nighttime work, few studies have characterized the causes of sleep disturbance in night shift workers beyond circadian misalignment. Recent research suggest that high sleep reactivity to stress (a predisposition for sleep disturbance due to stress) may also lead to sleep difficulties in shift workers. This study investigated if sleep reactivity is an independent predictor of daytime sleep disturbances after controlling for circadian phase.

Methods

Night shift workers (N= 48) completed an 8 hour polysomnography (PSG) during the daytime following a night shift (9am - 4pm). Circadian phase was measured using melatonin assays of saliva samples collected over 24 hours under dim light (&lt;10 lux; Dim Light Melatonin Onset [DLMO]). Sleep reactivity was measured using the Ford Insomnia Response to Stress Test (FIRST). Linear regressions were conducted with PSG sleep parameters as outcome variables: difficulty falling asleep (Sleep Onset Latency [SOL] and Latency to Persistent Sleep [LPS]), difficulty staying asleep (Wake After Sleep Onset [WASO]), and sleep duration (Total Sleep Time [TST]). FIRST was tested as a predictor controlling for DLMO.

Results

After controlling for circadian phase, higher FIRST scores was associated with more difficulty staying asleep (WASO: t[45]=4.059, p&lt;0.001) and shorter sleep duration (TST: t[45] = -4.403, p&lt;0.0001), but not predictive of difficulty falling asleep (SOL: p&gt;0.05). However, higher FIRST scores did predict a longer latency to persistent sleep (LPS: t[45]=2.272, p&lt;0.05).

Conclusion

These results suggest that sleep reactivity to stress and circadian misalignment are independent processes that are both associated with disrupted daytime sleep in night shift workers. Given that night shift work can also cause psychosocial stress, treatments focused on circadian misalignment alone may not be sufficient. Our study highlights the need to consider sleep reactivity in the clinical management of shift work disorder.

Support

Support for this study was provided to PC by NHLBI (K23HL138166).

0203 To and From the Night Shift: Risky On-the-Road Driving in Night Shift Workers

Introduction

Drowsy driving is a common occupational hazard for night shift workers (NSWs). While sleep loss is commonly identified as the primary culprit of drowsy driving, another critical factor to consider is circadian phase. However, the role of circadian phase in driving safety has not been well characterized in NSWs. This study examined if dim light melatonin offset (DLMOff, i.e. the cessation of melatonin secretion) is also a relevant phase marker of susceptibility to four different subtypes of risky on-the-road driving behaviors.

Methods

On-the-road driving was monitored over 8 weeks via a mobile application that tracked risky driving behaviors using accelerometer and GPS data from cell phones (N=15; 3052 total driving events recorded). Risky driving behaviors included: 1) frequency of hard-braking events, 2) frequency of aggressive-acceleration events, 3) duration of excessive-speeding, and 4) duration of phone-usage. At week 2, participants spent 24 hours in-lab where hourly saliva samples were collected and assayed for melatonin, and DLMOff was calculated. Phase angle of driving events relative to DLMOff was used as the predictor in nested mixed-effects regressions, with risky driving behaviors as the outcome variables.

Results

The most common occurrences of risky driving were phone-usage and hard-braking. On average, NSWs had 46.7% and 42.0% of driving events with at least one occurrence of phone-usage and hard-braking, respectively. Rates of aggressive-acceleration and speeding were 24.4% and 20.4%. Positive phase angles (i.e. driving after DLMOff) were associated with reduced rates of hard-braking and aggressive-acceleration, but not of phone-usage and excessive-speeding. Specifically, rates of hard-braking and aggressive-acceleration decreased by 4.5% (p&lt;.01) and 3.4% (p=.05) every two hours following DLMOff, respectively.

Conclusion

The study suggests DLMOff appears to be an important variable for predicting accident risk in NSWs. If replicated, circadian phase should be considered in recommendations to increase occupational health and safety of NSWs.

Support

Support for this study was provided to PC by NHLBI (K23HL138166).

0465 Association Between Physical or Sexual Abuse and Sleep Reactivity in Patients with Insomnia

Introduction

Physical and sexual abuse are common and have demonstrated associations with insomnia. A common factor predisposing individuals to the development of insomnia is sleep reactivity, yet no studies have determined the relationship between sleep reactivity and physical and/or sexual abuse.

Methods

Patients with DSM-5 insomnia disorder (N = 658; 519 F; mean age = 45.03) participated in an online randomized controlled trial of behavioral treatment of insomnia. Participants completed the Insomnia Severity Index (ISI), Ford Insomnia Response to Stress Test (FIRST), and demographic information at baseline. Abuse history was assessed with a single 4-choice item asking participants if they had a history of physical or sexual abuse. One-way analysis of variance was used to determine the level of sleep reactivity in each of the 4 abuse groups (none, physical, sexual, both) controlling for insomnia (ISI). Post-hoc analyses also compared differences in self-reported difficulties falling and staying asleep.

Results

Compared to those with no abuse history (n = 465), patients who reported both physical and sexual abuse (n = 50) had significantly elevated FIRST scores (p &lt; .001). Results remained significant after controlling for severity of insomnia, age, and gender. Post-hoc analyses showed group differences in sleep onset latency but not wake after sleep onset.

Conclusion

Combined physical and sexual abuse are associated with higher levels of sleep reactivity to stress, and that the effects may be most prominent for difficulties falling asleep and not sleep maintenance. Prospective studies are needed to determine the potential effects of abuse on sleep reactivity, and whether sensitization of the sleep system to stress constitutes an etiological pathway in the development of insomnia disorder in survivors of abuse. Future work should also investigate potential overlapping biological markers of abuse and sleep reactivity.

Support

This study was funded by the Robert Wood Johnson Foundation (PI: Drake).

Children and adolescents with type 1 and type 2 diabetes mellitus in the Pediatric Diabetes Consortium Registries: comparing clinical characteristics and glycaemic control

AIM

To compare the characteristics of children and adolescents with type 1 vs. type 2 diabetes in the Pediatric Diabetes Consortium (PDC) registries.

METHODS

Participants were 10 to < 21 years of age at diagnosis; there were 484 with type 1 diabetes and 1236 with type 2 diabetes.

RESULTS

Children and adolescents with type 2 diabetes were more likely to be female, overweight/obese, and from low-income, minority ethnic families. Children and adolescents with type 1 diabetes were more likely to present with diabetic ketoacidosis and have higher mean HbA_1c levels at diagnosis. More than 70% in both cohorts achieved target HbA_1c levels < 58 mmol/mol (< 7.5%) within 6 months, but fewer participants with type 1 than type 2 diabetes were able to maintain target HbA_1c levels after 6 months consistently throughout 3 years post diagnosis. Of the 401 participants with type 2 diabetes with ≥ 24 months diabetes duration on enrolment in the registry, 47% required no insulin treatment. Median C-peptide levels were 1.43 mmol/l in the subset of participants with type 2 diabetes in whom it was measured, but only 0.06 mmol/l in the subset with type 1 diabetes.

CONCLUSIONS

Although families of children and adolescents with type 2 diabetes face greater socio-economic obstacles and risk factors for poor diabetes outcomes, the greater retention of residual endogenous insulin secretion likely contributes to the increased ability of children and adolescents with type 2 diabetes to maintain target HbA_1c during the first 3 years of diabetes diagnosis.

Fluoro-Photoacoustic Polymeric Renal Reporter for Real-Time Dual Imaging of Acute Kidney Injury

Photoacoustic (PA) imaging agents detect disease tissues and biomarkers with increased penetration depth and enhanced spatial resolution relative to traditional optical imaging, and thus hold great promise for clinical applications. However, existing PA imaging agents often encounter the issues of slow body excretion and low-signal specificity, which compromise their capability for in vivo detection. Herein, a fluoro-photoacoustic polymeric renal reporter (FPRR) is synthesized for real-time imaging of drug-induced acute kidney injury (AKI). FPRR simultaneously turns on both near-infrared fluorescence (NIRF) and PA signals in response to an AKI biomarker (γ-glutamyl transferase) with high sensitivity and specificity. In association with its high renal clearance efficiency (78% at 24 h post-injection), FPRR can detect cisplatin-induced AKI at 24 h post-drug treatment through both real-time imaging and optical urinalysis, which is 48 h earlier than serum biomarker elevation and histological changes. More importantly, the deep-tissue penetration capability of PA imaging results in a signal-to-background ratio that is 2.3-fold higher than NIRF imaging. Thus, the study not only demonstrates the first activatable PA probe for real-time sensitive imaging of kidney function at molecular level, but also highlights the polymeric probe structure with high renal clearance.

Activatable Phototheranostic Materials for Imaging-Guided Cancer Therapy

Cancer theranostics, which combines diagnostic and therapeutic effects into one entity, holds promise in precision medicine. Conventional theranostic agents possess always-on imaging signals and cytotoxic effects and thus often encounter poor selectivity or specificity in cancer treatment. To tackle this issue, activatable phototheranostic materials (PMs) have been developed to simultaneously and specifically turn on their diagnostic signals (fluorescence/self-luminescence/photoacoustic signals) and photothermal/photodynamic effects in response to cancer hallmarks. This Review summarizes the recent progress in the design, synthesis and proof-of-concept applications of activatable PMs. The molecular engineering strategy to increase tumor accumulation and enhance treatment efficacy are highlighted. Current challenges and future perspectives in this emerging field are also discussed.

Near-Infrared Photoactivatable Semiconducting Polymer Nanoblockaders for Metastasis-Inhibited Combination Cancer Therapy

Inhibition of protein biosynthesis is a promising strategy to develop new therapeutic modalities for cancers; however, noninvasive precise regulation of this cellular event in living systems has been rarely reported. In this study, a semiconducting polymer nanoblockader (SPN_B ) is developed that can inhibit intracellular protein synthesis upon near-infrared (NIR) photoactivation to synergize with photodynamic therapy (PDT) for metastasis-inhibited cancer therapy. SPN_B is self-assembled from an amphiphilic semiconducting polymer which is grafted with poly(ethylene glycol) conjugated with a protein biosynthesis blockader through a singlet oxygen (¹ O₂ ) cleavable linker. Such a designed molecular structure not only enables generation of ¹ O₂ under NIR photoirradiation for PDT, but also permits photoactivation of blockaders to terminate protein translation. Thereby, SPN_B exerts a synergistic action to afford an enhanced therapeutic efficacy in tumor ablation. More importantly, SPN_B -mediated photoactivation of protein synthesis inhibition precisely and remotely downregulates the expression levels of metastasis-related proteins in tumor tissues, eventually contributing to the complete inhibition of lung metastasis. This study thus proposes a photoactivatable protherapeutic design for metastasis-inhibited cancer therapy.

[Effects of low temperature on trehalose and trehalase contents in Culex pipiens pallens]

OBJECTIVE

To examine the effect of low temperature on trehalose and trehalase levels in Culex pipiens pallens.

METHODS

The fourth instar larvae and female adult mosquitoes of Cx. pipiens pallens were exposed at 4 ℃ for 0, 1, 3, 6, 12, 18, 24 h and 0, 1, 3, 6, 12, 18, 24, 36, 48, 72 h, respectively. Then, the trehalose and trehalase contents were detected by enzyme-linked immunosorbent assay (ELISA) in mosquitoes.

RESULTS

The contents of trehalose and trehalase significantly increased in the larval and female adult mosquitoes post-exposure to low temperature. The changing trend of trehalose levels was consistent in the larval and female adult mosquitoes, and the highest levels were (2.458 8 ± 0.379 2) mg/g and (2.825 7 ± 0.211 1) mg/g 3 h post-exposure to low temperature, respectively. The trehalose and trehalase levels fluctuated greatly within the first 6 h post-exposure to low temperature. Following adaptation for a period of time, the trehalose and trehalase levels remained at a relatively high level.

CONCLUSIONS

Low temperature may induce the production of trehalose and trehalase in Cx. pipiens pallens, and the trehalose and trehalase may play an important role in the improvement of the cold resistance.

LncRNA KCNQ1OT1 controls cell proliferation, differentiation and apoptosis by sponging miR-326 to regulate c-Myc expression in acute myeloid leukemia

Long noncoding RNAs (lncRNAs) have been reported to play essential roles in development and treatment of acute myeloid leukemia (AML). However, the role of lncRNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (KCNQ1OT1) in AML progression and its mechanism remain largely unknown. The expressions of KCNQ1OT1, microRNA-326 (miR-326) and c-Myc were measured by quantitative real-time polymerase chain reaction and western blot, respectively. Phorbol myristate acetate (PMA) was used for cell differentiation. Cell proliferation, apoptosis and differentiation were measured by MTT assay, flow cytometry and qRT-PCR, respectively. The interaction between miR-326 and KCNQ1OT1 or c-Myc was explored by luciferase activity, RNA immunoprecipitation or RNA pull-down assay. We found that the expression of KCNQ1OT1 was enhanced in AML samples compared with control. KCNQ1OT1 knockdown inhibited cell proliferation but promoted apoptosis and cell differentiation. KCNQ1OT1 was a decoy of miR-326 and c-Myc was a target of miR-326. KCNQ1OT1 regulated AML cell proliferation, apoptosis and differentiation by sponging miR-326. Moreover, overexpression of miR-326 suppressed proliferation but promoted apoptosis and PMA-induced differentiation by targeting c-Myc in AML cells. Besides, c-Myc protein level was suppressed by KCNQ1OT1 interference and rescued by miR-326 abrogation. Our data showed that KCNQ1OT1 regulates proliferation, differentiation and apoptosis in AML cells by acting as a competing endogenous RNA (ceRNA) for miR-326 to regulate c-Myc, providing a novel avenue for AML treatment.

[Study on insecticide resistance of Culex pipiens pallens in southwest region of Shandong Province]

OBJECTIVE

To explore the sensitivity of Culex pipiens pallens to common chemical insecticides in the southwestern region of Shandong Province, so as to provide a theoretical basis for the development of reasonable and effective mosquito control measures.

METHODS

The resistance of Cx. pipiens pallens larvae to 5 chemical insecticides, such as cypermethrin, deltamethrin, DDVP, propoxur, and acetofenate were tested by using the WHO biological test method in 2018, and the co-toxicity coefficients after compounding the above-mentioned insecticides were tested by using a drug compounding method.

RESULTS

The resistance indexes of Cx. pipiens pallens to cypermethrin, deltamethrin, DDVP, propoxur, and acetofenate in 3 cities were 144.43-557.54, 118.17-445.33, 6.44-19.00, 2.37-8.10, and 0.88-2.98, respectively, and expect the difference between the DDVP resistances of Cx. pipiens pallens in Jining City and Heze City was not statistically significant (P > 0.05), all the other differences were statistically significant (all P < 0.05). The synergistic coefficients of cypermethrin + DDVP, cypermethrin + propoxur, DDVP + acetofenate, and propoxur + acetofenate were 199.58 - 456.95, 190.56 - 292.37, 123.32 - 319.24, and 192.31 - 367.32, respectively. The lower synergism was observed by using the mixture of DDVP + propoxur (synergistic coefficient: 99.87-108.36) .

CONCLUSIONS

After decades of chemical control, Cx. pipiens pallens in the southwestern region of Shandong Province has produced different degrees of resistance to common chemical insecticides. Therefore, comprehensive control measures should be taken to control mosquito breeding and prevent the development of insecticide resistance.