Structural and biochemical mechanisms of NLRP1 inhibition by DPP9.

Nucleotide-binding domain, leucine-rich repeat receptors (NLRs) mediate innate immunity by forming inflammasomes. Activation of the NLR protein NLRP1 requires autocleavage within its function-to-find domain (FIIND)1-7. In resting cells, the dipeptidyl peptidases DPP8 and DPP9 interact with the FIIND of NLRP1 and suppress spontaneous NLRP1 activation8,9; however, the mechanisms through which this occurs remain unknown. Here we present structural and biochemical evidence that full-length rat NLRP1 (rNLRP1) and rat DPP9 (rDPP9) form a 2:1 complex that contains an autoinhibited rNLRP1 molecule and an active UPA-CARD fragment of rNLRP1. The ZU5 domain is required not only for autoinhibition of rNLRP1 but also for assembly of the 2:1 complex. Formation of the complex prevents UPA-mediated higher-order oligomerization of UPA-CARD fragments and strengthens ZU5-mediated NLRP1 autoinhibition. Structure-guided biochemical and functional assays show that both NLRP1 binding and enzymatic activity are required for DPP9 to suppress NLRP1 in human cells. Together, our data reveal the mechanism of DPP9-mediated inhibition of NLRP1 and shed light on the activation of the NLRP1 inflammasome.

Deep Learning Models for Predicting Hearing Thresholds Based on Swept-Tone Stimulus-Frequency Otoacoustic Emissions.

OBJECTIVES: This study aims to develop deep learning (DL) models for the quantitative prediction of hearing thresholds based on stimulus-frequency otoacoustic emissions (SFOAEs) evoked by swept tones. DESIGN: A total of 174 ears with normal hearing and 388 ears with sensorineural hearing loss were studied. SFOAEs in the 0.3 to 4.3 kHz frequency range were recorded using linearly swept tones at a rate of 2 Hz/msec, with stimulus level changing from 40 to 60 dB SPL in 10 dB steps. Four DL models were used to predict hearing thresholds at octave frequencies from 0.5 to 4 kHz. The models-a conventional convolutional neural network (CNN), a hybrid CNN-k-nearest neighbor (KNN), a hybrid CNN-support vector machine (SVM), and a hybrid CNN-random forest (RF)-were individually built for each frequency. The input to the DL models was the measured raw SFOAE amplitude spectra and their corresponding signal to noise ratio spectra. All DL models shared a CNN-based feature self-extractor. They differed in that the conventional CNN utilized a fully connected layer to make the final regression decision, whereas the hybrid CNN-KNN, CNN-SVM, and CNN-RF models were designed by replacing the last fully connected layer of CNN model with a traditional machine learning (ML) regressor, that is, KNN, SVM, and RF, respectively. The model performance was evaluated using mean absolute error and SE averaged over 20 repetitions of 5 × 5 fold nested cross-validation. The performance of the proposed DL models was compared with two types of traditional ML models. RESULTS: The proposed SFOAE-based DL models resulted in an optimal mean absolute error of 5.98, 5.22, 5.51, and 6.06 dB at 0.5, 1, 2, and 4 kHz, respectively, superior to that obtained by the traditional ML models. The produced SEs were 8.55, 7.27, 7.58, and 7.95 dB at 0.5, 1, 2, and 4 kHz, respectively. All the DL models outperformed any of the traditional ML models. CONCLUSIONS: The proposed swept-tone SFOAE-based DL models were capable of quantitatively predicting hearing thresholds with satisfactory performance. With DL techniques, the underlying relationship between SFOAEs and hearing thresholds at disparate frequencies was explored and captured, potentially improving the diagnostic value of SFOAEs.

Factors influencing rapid antiretroviral therapy initiation in Jiulongpo, Chongqing, China: a retrospective cohort from 2018 to 2022.

BACKGROUND: Antiretroviral Therapy (ART) is pivotal in extending the lives of people living with HIV (PLWH) and minimizing transmission. Rapid ART initiation, defined as commencing ART within seven days of HIV diagnosis, is recommended for all PLWH. METHOD: A retrospective cohort study was conducted using data from the China Information System for Disease Control and Prevention. This study included PLWH diagnosed between January 2018 and December 2021 and treated by December 2022. Factors influencing rapid ART initiation were examined using univariate and multivariate Cox regression analyses. RESULTS: The study analyzed 1310 cases. The majority were male (77.4%), over 50 years old (46.7%), and contracted HIV through heterosexual transmission (70.0%). Rapid ART initiation was observed in 36.6% (n = 479) of cases, with a cumulative treatment rate of 72.9% within 30 days post-diagnosis. Heterosexual contact was associated with longer intervals from diagnosis to treatment initiation compared to homosexual contact (Adjusted Hazard Ratio (HR) = 0.813, 95% Confidence Interval (CI): 0.668-0.988). Individuals older than 50 years (Adjusted HR = 1.852, 95%CI: 1.149-2.985) were more likely to initiate ART rapidly. Conversely, treatment at the Second Public Hospital (Adjusted HR = 0.483, 95% CI: 0.330-0.708) and a CD4 cell counts above 500 (Adjusted HR = 0.553, 95% CI: 0.332-0.921) were associated with a lower likelihood of initiating treatment within seven days. CONCLUSIONS: A higher CD4 cell counts and receiving care in local public hospitals may deter rapid ART initiation. Providing CD4 counts results at diagnosis and offering testing and treatment in the same facility could enhance the rate of rapid ART initiation.

Effectiveness of convalescent plasma therapy in severe COVID-19 patients.

Currently, there are no approved specific antiviral agents for novel coronavirus disease 2019 (COVID-19). In this study, 10 severe patients confirmed by real-time viral RNA test were enrolled prospectively. One dose of 200 mL of convalescent plasma (CP) derived from recently recovered donors with the neutralizing antibody titers above 1:640 was transfused to the patients as an addition to maximal supportive care and antiviral agents. The primary endpoint was the safety of CP transfusion. The second endpoints were the improvement of clinical symptoms and laboratory parameters within 3 d after CP transfusion. The median time from onset of illness to CP transfusion was 16.5 d. After CP transfusion, the level of neutralizing antibody increased rapidly up to 1:640 in five cases, while that of the other four cases maintained at a high level (1:640). The clinical symptoms were significantly improved along with increase of oxyhemoglobin saturation within 3 d. Several parameters tended to improve as compared to pretransfusion, including increased lymphocyte counts (0.65 × 109/L vs. 0.76 × 109/L) and decreased C-reactive protein (55.98 mg/L vs. 18.13 mg/L). Radiological examinations showed varying degrees of absorption of lung lesions within 7 d. The viral load was undetectable after transfusion in seven patients who had previous viremia. No severe adverse effects were observed. This study showed CP therapy was well tolerated and could potentially improve the clinical outcomes through neutralizing viremia in severe COVID-19 cases. The optimal dose and time point, as well as the clinical benefit of CP therapy, needs further investigation in larger well-controlled trials.

Anemoside B4 Exerts Hypoglycemic Effect by Regulating the Expression of GLUT4 in HFD/STZ Rats.

Anemoside B4 (B4) is a saponin that is extracted from Pulsatilla chinensis (Bge.), and Regel exhibited anti-inflammatory, antioxidant, antiviral, and immunomodulatory activities. However, its hypoglycemic activity in diabetes mellitus has not been evaluated. Here, we explored the effect of B4 on hyperglycemia and studied its underlying mechanism of lowering blood glucose based on hyperglycemic rats in vivo and L6 skeletal muscle cells (L6) in vitro. The rats were fed a high-fat diet (HFD) for one month, combined with an intraperitoneal injection of 60 mg/kg streptozotocin (STZ) to construct the animal model, and the drug was administrated for two weeks. Blood glucose was detected and the proteins and mRNA were expressed. Our study showed that B4 significantly diminished fasting blood glucose (FBG) and improved glucose metabolism. In addition, B4 facilitated glucose utilization in L6 cells. B4 could enhance the expression of glucose transporter 4 (GLUT4) in rat skeletal muscle and L6 cells. Mechanistically, B4 elevated the inhibition of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways. Furthermore, we confirmed the effect of B4 on glucose uptake involved in the enhancement of GLUT4 expression in part due to PI3K/AKT signaling by using a small molecule inhibitor assay and constructing a GLUT4 promoter plasmid. Taken together, our study found that B4 ameliorates hyperglycemia through the PI3K/AKT pathway and promotes GLUT4 initiation, showing a new perspective of B4 as a potential agent against diabetes.

Surface Modification of lactose carrier particles using a fluid bed coater to improve fine particle fraction for dry powder inhalers.

Surface roughness of carrier particles can impact dry powder inhaler (DPI) performance. There are opposing views on the effect of roughness on DPI performance. Hence, a systematic approach is needed to modify carrier surfaces and evaluate the impact on drug delivery. Carrier particle surfaces were modified by fluid bed coating with saturated lactose containing micronized lactose of different sizes (2, 5 and 8 µm) and coated to different levels (20, 40, 60 and 80%). Their drug delivery performance was assessed by the fine particle fraction (FPF). Roughness parameters, mean arithmetic roughness (Ra) and arithmetic mean height (Sa), of the carrier particles, were also evaluated using optical profilometry and scanning laser microscopy. Generally, particles of higher Ra had higher FPF. Higher Sa resulted in higher FPF only for particles with 60 and 80% coat levels. Reduced contact surface area between the drug particle and rougher carrier particle resulted in easier drug detachment during aerosolization. The 5 µm micronized lactose produced optimal carrier particles with respect to FPF and surface roughness. The study highlighted that with the ideal particles for surface roughening and coating level, surface roughening could be efficiently achieved by fluid bed coating for superior DPI performance.

Three AP2/ERF family members modulate flavonoid synthesis by regulating type IV chalcone isomerase in citrus.

Flavanones and flavones are excellent source of bioactive compounds but the molecular basis of their highly efficient production remains elusive. Chalcone isomerase (CHI) family proteins play essential roles in flavonoid biosynthesis but little are known about the transcription factors controlling their gene expression. Here, we identified a type IV CHI (designated as CitCHIL1) from citrus which enhances the accumulation of citrus flavanones and flavones (CFLs). CitCHIL1 participates in a CFL biosynthetic metabolon and assists the cyclization of naringenin chalcone to (2S)-naringenin, which leads to the efficient influx of substrates to chalcone synthase (CHS) and improves the catalytic efficiency of CHS. Overexpressing CitCHIL1 in Citrus and Arabidopsis significantly increased flavonoid content and RNA interference-induced silencing of CitCHIL1 in citrus led to a 43% reduction in CFL content. Three AP2/ERF transcription factors were identified as positive regulators of the CitCHIL1 expression. Of these, two dehydration-responsive element binding (DREB) proteins, CitERF32 and CitERF33, activated the transcription by directly binding to the CGCCGC motif in the promoter, while CitRAV1 (RAV: related to ABI3/VP1) formed a transcription complex with CitERF33 that strongly enhanced the activation efficiency and flavonoid accumulation. These results not only illustrate the specific function that CitCHIL1 executes in CFL biosynthesis but also reveal a new DREB-RAV transcriptional complex regulating flavonoid production.

Maximising the ability of stimulus-frequency otoacoustic emissions to predict hearing status and thresholds using machine-learning models.

OBJECTIVE: This study aimed to maximise the ability of stimulus-frequency otoacoustic emissions (SFOAEs) to predict hearing status and thresholds based on machine-learning models. DESIGN: SFOAE data and audiometric thresholds were collected at octave frequencies from 0.5 to 8 kHz. Support vector machine, k-nearest neighbour, back propagation neural network, decision tree, and random forest algorithms were used to build classification models for status identification and to develop regression models for threshold prediction. STUDY SAMPLE: About 230 ears with normal hearing and 737 ears with sensorineural hearing loss. RESULTS: All classification models yielded areas under the receiver operating characteristic curve of 0.926-0.994 at 0.5-8 kHz, superior to the previous SFOAE study. The regression models produced lower standard errors (8.1-12.2 dB, mean absolute errors: 5.53-8.97 dB) as compared to those for distortion-product and transient-evoked otoacoustic emissions previously reported (8.6-19.2 dB). CONCLUSIONS: SFOAEs using machine-learning approaches offer promising tools for the prediction of hearing capabilities, at least at 0.5-4 kHz. Future research may focus on further improvements in accuracy and reductions in test time to improve clinical utility.

Characterization of a caffeoyl-CoA O-methyltransferase-like enzyme involved in biosynthesis of polymethoxylated flavones in Citrus reticulata.

Polymethoxylated flavones (PMFs), which accumulate exclusively in fruit peel of citrus, play important physiological and pharmacological roles but the genetic basis for the methylation of flavonoids has not been fully elucidated in citrus. Here we characterize a caffeoyl-CoA O-methyltransferase-like enzyme, designated CrOMT1. The expression pattern of CrOMT1 was highly correlated with the concentration of the three major PMFs in two different citrus fruit tissues during fruit maturation. Exposure of fruit to UV-B radiation sharply increased the level of CrOMT1 transcripts and also led to the accumulation of three PMFs. The potential role of CrOMT1 was studied by testing the catalytic activity of recombinant CrOMT1 with numerous possible substrates in vitro. The enzyme could most efficiently methylate flavones with neighboring hydroxy moieties, with high catalytic efficiencies found with 6-OH- and 8-OH-containing compounds, preferences that correspond precisely with the essential methylation sites involved in the synthesis of the three naturally occurring PMFs in Citrus reticulata. This indicates that CrOMT1 is capable of in vitro methylation reactions required to synthesize PMFs in vivo. Furthermore, transient overexpression of CrOMT1 increased levels of the three major PMFs in fruit, indicating that CrOMT1 is likely to play an essential role in the biosynthesis of PMFs in citrus.

Viral metagenomics reveals sapoviruses of different genogroups in stool samples from children with acute gastroenteritis in Jiangsu, China.

Sapoviruses (SAVs), including several genogroups (GI to GV), are one of the causes of acute gastroenteritis (AGE). In this study, viral metagenomics revealed the presence of sapoviruses of different genogroups in stool from children with AGE. Eight different complete SAV genomes were determined, of which five belonged to GI and the other three belonged to GII, GIV and GV, respectively. Although they were highly similar to published sequences, the GIV and GV were the first complete genome sequences of these SAVs found in China. In a prevalence investigation, 19% of subjects with AGE were positive for SAVs, while none of the control group was positive.

Characterization of a Flavonoid 3'/5'/7-O-Methyltransferase from Citrus reticulata and Evaluation of the In Vitro Cytotoxicity of Its Methylated Products.

O-methylation of flavonoids is an important modification reaction that occurs in plants. O-methylation contributes to the structural diversity of flavonoids, which have several biological and pharmacological functions. In this study, an O-methyltransferase gene (CrOMT2) was isolated from the fruit peel of Citrus reticulata, which encoding a multifunctional O-methyltransferase and could effectively catalyze the methylation of 3'-, 5'-, and 7-OH of flavonoids with vicinal hydroxyl substitutions. Substrate preference assays indicated that this recombinant enzyme favored polymethoxylated flavones (PMF)-type substrates in vitro, thereby providing biochemical evidence for the potential role of the enzyme in plants. Additionally, the cytotoxicity of the methylated products from the enzymatic catalytic reaction was evaluated in vitro using human gastric cell lines SGC-7901 and BGC-823. The results showed that the in vitro cytotoxicity of the flavonoids with the unsaturated C2-C3 bond was increased after being methylated at position 3'. These combined results provide biochemical insight regarding CrOMT2 in vitro and indicate the in vitro cytotoxicity of the products methylated by its catalytic reaction.

Cumulative risk assessment of phthalates in edible vegetable oil consumed by Chinese residents.

BACKGROUND: Phthalates have been widely used as plasticizers in various industries and are widely focused on in the international community as a result of their reproductive toxicity. Exposure of Chinese residents to phthalates via edible vegetable oil occurs often. In the present study, gas chromatography-mass spectrometry was used to detect the two main phthalates bis(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) in four major edible vegetable oil sources: an edible oil blend, soybean oil, peanut oil and rapeseed oil (a total of 1016 samples), as collected throughout China. Furthermore, cumulative risk assessment was used to estimate the reproductive health risk to Chinese residents caused by the phthalates that come from edible vegetable oils. RESULTS: Both phthalates were detected in four major edible vegetable oil sources. The phthalate with the highest detection rate was DBP (13.48%), followed by DEHP (7.78%). The results of the cumulative risk assessment showed that the hazard indices of these two phthalates in edible vegetable oils were less than 1, except in soybean oil. Nevertheless, the two phthalates had the lowest detection rates in soybean oil, which were 1.94% (DEHP) and 5.16% (DBP). In China, contamination levels of phthalates in the soils where oil crops are cultivated have a great influence on the phthalate concentrations in edible vegetable oils. CONCLUSION: It is recommended that Chinese residents who are consuming soybean oil choose well-known brands and regularly change their brand of consumption. The phthalates in edible vegetable oils pose a relatively small reproductive health risk to Chinese residents. © 2019 Society of Chemical Industry.

Comprehensive study of dexamethasone on albumin biogenesis during normal and pathological renal conditions.

CONTEXT: Dexamethasone (DXM) has an anti-immunoinflammatory effect, and is often used in acute kidney injury (AKI). However, the effects of DXM on albumin (ALB) have not been fully studied. OBJECTIVE: To investigate the effects of DXM on ALB production and renal function. MATERIALS AND METHODS: Male Wistar rats were divided into normal and DXM groups (0.25, 0.5, 1 mg/kg for 5 days) (n = 15) for a dose-dependent study. Rats were divided into normal group and DXM groups (0.5 mg/kg for 3, 5, 7 days) (n = 9) for a time-dependent study. In AKI experiment, rats were divided into normal (saline), cisplatin (CP, 5 mg/kg, i.v.), CP + DXM groups (0.25, 0.5 and 1 mg/kg, i.m.) (n = 16). The blood and the organs were isolated for analysis. RESULTS: In normal, serum ALB (sALB) and serum total protein (sTP) increased in DXM group with sALB increased 19.8-32.2% (from small to large dosages); and 30.2-32.5.6% (from 3 to 7 days of DXM); sTP 15.7-22.6% and 14.2-24.3%; urine ALB (uALB) 31.5-392.3%, and 1047.2-1390.8%; urine TP (uTP) 0.68-173.1% and 98.0-504.9%, compared with normal groups. DXM increased the mRNA expression of Cebp and Hnf, suppressing podocin. In AKI, DXM decreased serum BUN (53.7%), serum Cre (73.4%), sALB (30.0%), sTP (18.7%), uALB (74.5%), uTP (449.3%), rescuing the suppressed podocin in kidney. CONCLUSIONS: DXM acts on Cebp and Hnf and promotes ALB production. This finding helps to evaluate the rationale of DXM for kidney injury.

[Study on therapeutic effect and its related mechanism of anemoside B4 on ischemia reperfusion injury induced by renal artery and vein ligation in rats].

The aim of this paper was to investigate the effect and mechanism of anemoside B4 on renal ischemia reperfusion injury in rats. A total of 50 rats were randomly divided into the model group(NS) and anemoside B4 low-dose(1.25 mg·kg~(-1)), medium-dose(2.5 mg·kg~(-1)) and high-dose(5 mg·kg~(-1)) groups after the right kidney was removed and the left kidney was ligated to make the ischemia reperfusion model. Another 10 rats were selected as sham operation group only for normal control group(NS, received normal saline). Automatic biochemical analyzer was used to measure serum blood urea nitrogen(BUN), creatinine(Cre), cerebrospinal fluid(CSF) and urinemicroalbumin(mALB) levels after 5 days of tail vein injection treament. Total urine protein and total urinary albu-min were calculated and kidney samples were collected. Histopathological changes of renal tissues were observed by PAS staining. Western blot analysis was performed to detect the protein expressions of TLR4 and NF-κB in renal inflammatory factors related to NLRP3 pathway and TLR4/NF-κB pathway. The results showed that the levels of BUN, Cre, urinary total protein and urinary total albumin in the model group were significantly increased(P<0.01), with severe renal tubule injury was serious, manifested by obvious expansion of renal tubules, more serious tubular proteins, and some tubular epithelial cells were exfoliated. At the same time, the expression of inflammatory factors related to NLRP3 pathway and TLR4/NF-κB pathway increased significantly(P<0.01 or P<0.05). The levels of BUN, Cre were reduced in different doses of anemoside B4(P<0.05). The levels of total urinary protein and total urinary albumin were decreased in the low and high dose groups of anemoside B4.The level of total urinary albumin in the high-dose group of anemoside B4 was significantly reduced(P<0.05).Renal tubular injury was alleviated, tubular epithelial cell exfoliation was reduced, and the expression of related inflammatory factors was reduced in different degrees(P<0.01 or P<0.05). This study showed that anemoside B4 could alleviate renal ischemia-reperfusion injury in rats. And its mechanism may be related to the inhibition of inflammatory factors related to response mediated by NLRP3 pathway and TLR4/NF-κB pathway by anemoside B4.

[Expression characteristics of inflammatory and apoptosis factors and regulatory effect of anemoside B4 in mice with acute kidney injury].

This paper was aimed to observe the effect of anemoside B4(hereinafter referred to as B4) on cisplatin-induced acute kidney injury in mice, and to investigate its possible mechanism in renal protection from inflammation and apoptosis aspects. Mice were divided into normal group, model group, dexamethasone positive group and B4 high, middle and low dose groups(5, 2.5, and 1.25 mg·kg~(-1 )doses). All the other mice groups except normal group were given with tail vein injection of cisplatin(15 mg·kg~(-1)) to induce acute kidney injury models. The drug administration was started on the day of modeling, and lasted for 4 days. After 1 hour of the last injection, orbital blood was collected. After the serum was separated, serum urea nitrogen(BUN), creatinine(Cre), total protein(TP), and albumin(ALB) were tested by using an automatic biochemical analyzer; the changes of kidney pathological morphology were observed by PAS staining; the protein expression levels of inflammatory factors including nucleotide binding oligomerization domain-like receptor(NLRP3), cysteinyl aspartate specific proteinase 1(caspase-1), interleukin-18(IL-18), interleukin-1ß(IL-1ß), tumor necrosis factor(TNF-α), and interleukin-6(IL-6) and apoptosis factors including p53, caspase-3, cleaved-caspase-3, Bcl-2 associated X protein(Bax), and B-cell lymphoma-2(Bcl-2) were analyzed by Western blot. The results showed that B4 significantly reduced the serum BUN and Cre contents, and alleviated pathological changes in renal tissues, such as the shedding and degeneration of renal tubular epithelial cells, tubulin tubule type. B4 significantly down-regulated the protein expressions of p53, Bax, cleaved-caspase-3 in the kidney and up-regulated the expression of Bcl-2/Bax. In model group, however, no significant up-regulation was observed in the protein expression levels of inflammatory cytokines(NLRP3, pro-caspase-1, IL-18, IL-1ß, TNF-α, IL-6). The results suggested that B4 had a certain protective effect on cisplatin-induced acute kidney injury, and could activate p53 signaling pathway related apoptotic factors. B4 renal protective effect was mainly related to the regulation of p53 signaling pathway, while NLRP3 inflammasome and related inflammatory factors had no obvious response in this model.

Effects of copper on the growth, antioxidant enzymes and photosynthesis of spinach seedlings.

Examination of plants with strong Cu tolerance and an understanding of their Cu-tolerance mechanisms are of considerable significance for the remediation of Cu-contaminated soil. Although spinach may be a plant with strong Cu tolerance, the threshold of Cu tolerance in this plant and its physiological response mechanisms to Cu are still unclear. In this study, we examined that the effects of different Cu concentrations on the growth parameters, antioxidant enzyme activities, and photosynthesis of spinach seedlings. The results showed that when treated with a low Cu concentration (100 mg L-1 CuSO4), the biomass of spinach seedlings increased, whereas the MDA content, the activities of antioxidant enzymes, Pn, gs and Tr were not significantly different from those in the control (P > 0.05), and Y(II), qP reached their maximum values, indicating that a low Cu concentration (100 mg L-1 CuSO4) had minimal negative effects on the life activities of spinach seedlings. In contrast, when treated with high Cu concentrations (800-1000 mg L-1 CuSO4), the total biomass of spinach seedlings was markedly decreased, the MDA contents increased, antioxidant enzyme activities initially increased and then decreased to varying degrees, the contents of chlorophyll, Pn, Tr, Fv/Fm, qP, NPQ, and Y(II) were all decreased. However the growth of spinach did not terminate, implying that the lethal threshold concentration of Cu for spinach is greater than 1000 mg L-1 CuSO4 used in this study. In summary, spinach exhibits a high tolerance to Cu and can be considered as an alternative plant for the remediation of Cu-contaminated soils.

Comparison of the TLR4/NFκB and NLRP3 signalling pathways in major organs of the mouse after intravenous injection of lipopolysaccharide.

Context: Lipopolysaccharide (LPS) is often used to induce immunoinflammatory reactions. TLR4/NFκB and NLRP3 signalling are major factors for inflammation. Dexamethasone (DXM) has an anti-immunoinflammatory effect. Objective: To investigate the inflammatory reaction in pathological changes of organs and the expression of inflammatory signalling during LPS infection. Materials and methods: ICR mice were divided into control group (n = 9), LPS group (n = 15) and LPS + DXM group (n = 14). LPS (10 mg/kg) was injected intravenously in LPS group and LPS + DXM group, normal saline was injected to the control group; DXM (0.5 mg/kg) was given by intragastric administration. 12 h after LPS, the blood was collected and the organs were isolated for biochemical analysis, protein expression, and morphological examination. Results: The results showed that BUN, Cre, ALT, AST in the LPS group increased distinctly by 81.42, 67.84, 40.53 and 36.05%, respectively, and CK, ALP, TP and ALB decreased by 71.37, 60.6, 12.57 and 19.73%, respectively, compared with the control group. In the morphologic observation, local necrosis in the liver, arterial vasodilation in the heart and kidney, alveolar secretions and pulmonary interstitial in the lungs, and mucosal shedding in the small and large intestines, the expression of TLR4-NFκB signalling were up-regulated distinctly whereas NLRP3 signalling was less broadly affected. DXM can decrease BUN and Cre, downregulate the expression of TLR4-NFκB signalling, but has no effect on the organ damage based on morphology. Conclusion: Acute injuries induced by LPS are extensive. The inflammatory damage in small and large intestines, liver and kidney was more severe than other organs. TLR4-NFκB signalling was the major response to LPS stress.

[Study on acute kidney injury model induced by renal ischemia-reperfusion in rats].

In this study,in-depth systematic evaluation of rat of acute kidney injury(AKI) caused by renal arteriovenous ligation was conducted to better master and apply this model for drug research. Male SD rats of 2-3 months old were employed in this study.The left kidney was removed,and the right kidney received ligation for 40 min and reperfusion for 24 h. Serum creatinine(Crea),urea nitrogen(BUN) and the renal tissue sections were assayed as the basic indicators to evaluate their renal function. The mRNA expression of inflammatory necrosis factors and apoptotic factors was used to evaluate the mechanism of molecular pathophysiological changes. The results showed that the serum Crea and BUN caused by ligation of both renal arteries and veins were significantly higher than those of rats with renal artery ligation. After renal arteriovenous ligation for 40 min and reperfusion for 24 h in rats,the serum Crea of the rats varied from less than 100 µmol·L-1 to more than 430 µmol·L-1. Among them,5 rats showed less than 100 µmol·L-1 serum Crea,20 rats with 100-200 µmol·L-1 serum Crea and 12 rats with more than 430 µmol·L-1. Rats with serum Crea between 300-430 µmol·L-1 accounted for 66.3%(122/184) of the total number of the experiment rats. After 72 h reperfusion,serum Crea in the group of Crea 370-430 µmol·L-1 continued to increase,while the serum Crea in the group of Crea 200-300 µmol·L-1 and the group of Crea 300-370 µmol·L-1 recovered quickly. No matter serum Crea was elevated or decreased,the renal tubules showed pathological changes such as vacuolar degeneration or even necrosis. The mRNA expression levels of Toll-like receptor(TLR4),tumor necrosis factor(TNF-α) and interleukin(IL-6) in renal tissueswere significantly up-regulated,and the effect was most obvious in the group of serum Crea 370-430 µmol·L-1. The study indicated that the model for AKI caused by renal arteriovenous ligation and reperfusion is easy to operate,and the serum Crea and BUN have the characteristics of continuous increase,beneficial to the observation of drug effects. This acute kidney injury is mainly related to the pathophysiological response of inflammatory necrosis.

The influence of probe level on the tuning of stimulus frequency otoacoustic emissions and behavioral test in human.

BACKGROUND: Frequency selectivity (FS) of the auditory system is established at the level of the cochlea and it is important for the perception of complex sounds. Although direct measurements of cochlear FS require surgical preparation, it can also be estimated with the measurements of otoacoustic emissions or behavioral tests, including stimulus frequency otoacoustic emission suppression tuning curves (SFOAE STCs) or psychophysical tuning curves (PTCs). These two methods result in similar estimates of FS at low probe levels. As the compressive nonlinearity of cochlea is strongly dependent on the stimulus intensity, the sharpness of tuning curves which is relevant to the cochlear nonlinearity will change as a function of probe level. The present study aims to investigate the influence of different probe levels on the relationship between SFOAE STCs and PTCs. METHODS: The study included 15 young subjects with normal hearing. SFOAE STCs and PTCs were recorded at low and moderate probe levels for frequencies centred at 1, 2, and 4 kHz. The ratio or the difference of the characteristic parameters between the two methods was calculated at each probe level. The effect of probe level on the ratio or the difference between the parameters of SFOAE STCs and PTCs was then statistically analysed. RESULTS: The tuning of SFOAE STCs was significantly positively correlated with the tuning of the PTCs at both low and moderate probe levels; yet, at the moderate probe level, the SFOAE STCs were consistently broader than the PTCs. The mean ratio of sharpness of tuning at low probe levels was constantly around 1 while around 1.5 at moderate probe levels. CONCLUSIONS: Probe level had a significant effect on the sharpness of tuning between the two methods of estimating FS. SFOAE STC seems a good alternative measurement of PTC for FS assessment at low probe levels. At moderate probe levels, SFOAE STC and PTC were not equivalent measures of the FS in terms of their bandwidths. Because SFOAE STCs are not biased by higher levels auditory processing, they may represent cochlear FS better than PTCs.