In vitro antibacterial activity of danofloxacin against Escherichia coli in Gushi chickens and its residue depletion following multiple oral administration.

This study aimed to investigate the in vitro antibacterial activity of danofloxacin against Escherichia coli isolated from Gushi chickens, as well as the tissue distribution and residue depletion of danofloxacin in Gushi chickens following multiple oral administration. A total of 42 clinical E. coli strains were isolated from the cloaca of locally farmed Gushi chickens between August and October 2023. Then the minimum inhibitory concentration (MIC) of danofloxacin against these isolates was determined by broth microdilution method. Additionally, 42 healthy Gushi chickens were randomly divided into 6 groups, and danofloxacin was orally administered at a dose of 5 mg/kg body weight (BW) for 3 consecutive days. Plasma, intestinal content, and tissue samples, including muscle, skin + fat, liver, kidney, lung, and intestine, were collected at 4, 12, 24, 48, 72, and 120 h after the last administration. Danofloxacin concentrations in all samples were determined using a high-performance liquid chromatography (HPLC) method. The average concentration vs. time data were then subjected to noncompartmental analysis using Phoenix software, and withdrawal periods for danofloxacin in Gushi chickens were further determined with WT1.4 software, setting a 95% confidence interval. Results indicated a notable inhibitory effect of danofloxacin on E. coli, with an MIC50 of 0.5 µg/mL. Additionally, danofloxacin exhibited widespread distribution in Gushi chickens, detectable in all collected samples. Among all tissues, the liver exhibited the highest concentration, followed by the intestine. Even on the fifth day postadministration, danofloxacin persisted in skin + fat, liver, and lung. The elimination half-lives (t1/2λzs) of danofloxacin varied across samples: skin + fat (47.87 h), lung (30.61 h), liver (22.07 h), plasma (16.05 h), muscle (12.53 h), intestine (9.83 h), and kidney (6.34 h). Considering residue depletion and the maximum residue limit (MRL) of danofloxacin in poultry set by Chinese regulatory authorities, withdrawal periods for the kidney, muscle, liver, and skin + fat were determined as 1.03, 1.38, 3.34, and 5.85 d, respectively, rounded to a final withdrawal time of 6 d.

Eicosanoid Metabolomic Profile of Remdesivir Treatment in Rat Plasma by High-Performance Liquid Chromatography Mass Spectrometry.

Remdesivir, a nucleotide analog prodrug, has displayed pharmacological activity against SARS-CoV-2. Recently, eicosanoids are widely involved in regulating immunity and inflammation for COVID-19 patients. Rats were intravenously administered remdesivir at a dose of 5 mg/kg, and series of blood samples were collected before and after treatment. Targeted metabolomics regarding the eicosanoid profile were investigated and quantitated simultaneously using the previously reported reliable HPLC-MS/MS method. Additionally, interplay relationship between metabolomics and pharmacokinetic parameters was performed using the Pearson correlation analysis and PLS model. For the longitudinal metabolomics of remdesivir, metabolic profiles of the same rat were comparatively substantial at discrete sampling points. The metabolic fingerprints generated by individual discrepancy of rats were larger than metabolic disturbance caused by remdesivir. As for the transversal metabolomics, the prominent metabolic profile variation was observed between the baseline and treatment status. Except for TXB2, the inflammatory- and immunology-related eicosanoids of resolvin D2, 5-HEPE, 5-HETE, and DHA were significantly disturbed and reduced after single administration of remdesivir (p < 0.05, p < 0.001). Moreover, the metabolite of PGE2 correlated with GS-441524 (active metabolite of remdesivir) concentration and pharmacokinetic parameters of Cmax, AUC0-t, AUC0-infinity, and CL significantly. Eicosanoid metabolic profiles of remdesivir at both longitudinal and transversal levels were first revealed using the robust HPLC-MS/MS method. This initial observational eicosanoid metabolomics may lighten the therapy for fighting COVID-19 and further provide mechanistic insights of SARS-CoV-2 virus infection.

The Effects of 50 nm Unmodified Nano-ZnO on Lipid Metabolism and Semen Quality in Male Mice.

Fifty male mice were exposed to 50 nm unmodified nano-ZnO through intragastric administration for 90 days to detect the long-term effects of unmodified nano-ZnO in mice. Results showed that the blood glucose, serum follicle stimulating hormone, luteinizing hormone, testosterone, and estradiol were significantly decreased (p < 0.05). The serum triglyceride, total cholesterol, and low-density lipoprotein were significantly increased (p < 0.05). The semen quality of the 160 mg/kg·bw group were significantly lowered (p < 0.05). The liver and testis catalase and CuZn-SOD activities were significantly elevated (p < 0.05). The abilities of •OH inhibition in the livers and testes of the 160 mg/kg·bw group were significantly lowered (p < 0.05). The liver and testis MDA levels of the 160 mg/kg·bw group were significantly elevated (p < 0.05). Results indicate that exposure of nano-ZnO could induce lipid metabolism disorder, hyperlipidemia, and reproductive toxicity to male mice through oxidative injury.

Correction to: The Effects of 50 nm Unmodified Nano-ZnO on Lipid Metabolism and Semen Quality in Male Mice.

The original version of this article unfortunately contained a mistake. The correct title should be "The Effects of 50 nm Unmodified Nano-ZnO on Lipid Metabolism and Semen Quality in Male Mice". The original article has been corrected.

Long-Term Effects of Unmodified 50 nm ZnO in Mice.

Nanometer zinc oxide (nano-ZnO) is widely used in many kinds of fields. However, information about the toxicity and toxic mechanism of nano-ZnO is limited. The aims of this study were to investigate the long-term toxic effects of unmodified 50 nm ZnO administered by gavage in mice. After 90 days, hematological parameters, hepatic and renal functions, and oxidative and anti-oxidative status were measured. Pathological damages in livers, kidneys, and other tissues were also examined by hematoxylin and eosin (H&E) staining. The results showed that oral nano-ZnO exposure induced anemia and damages to liver and kidney, influenced the antioxidant system, and impacted functions of liver and kidney in mice after a 90-day exposure. The main cause for oxidative stress in vivo induced by nano-ZnO might be hydroxyl free radical. The lowest observed adverse effect level (LOAEL) was 40 mg/kg·bw, and the livers, kidneys, lungs, pancreas, and gastrointestinal tracts are the target organs.

Potassium channel Kv2.1 is regulated through protein phosphatase-1 in response to increases in synaptic activity.

The functional stability of neurons in the face of large variations in both activity and efficacy of synaptic connections suggests that neurons possess intrinsic negative feedback mechanisms to balance and tune excitability. While NMDA receptors have been established to play an important role in glutamate receptor-dependent plasticity through protein dephosphorylation, the effects of synaptic activation on intrinsic excitability are less well characterized. We show that increases in synaptic activity result in dephosphorylation of the potassium channel subunit Kv2.1. This dephosphorylation is induced through NMDA receptors and is executed through protein phosphatase-1 (PP1), an enzyme previously established to play a key role in regulating ligand gated ion channels in synaptic plasticity. Dephosphorylation of Kv2.1 by PP1 in response to synaptic activity results in substantial shifts in the inactivation curve of IK, resulting in a reduction in intrinsic excitability, facilitating negative feedback to neuronal excitability.

Dopamine modulates the off pathway in light-adapted mouse retina.

DL-2-Amino-4-phosphonobutyric acid (APB) is often used as a tool to block On pathways in studies of interactions between On and Off pathways in retinas. APB is an agonist of mGluR6 receptors and hyperpolarizes the On cone bipolar cells and rod bipolar cells. How APB affects Off responses of retinal ganglion cells (RGCs) in mouse retinas under dark and light adaptation is not clear. The light-evoked excitatory postsynaptic currents (light-evoked EPSCs) from Off and On-Off RGCs cells were recorded using whole-cell patch-clamp recording to assess how APB affects Off responses (light-evoked Off EPSCs) of RGCs in dark- and light-adapted mouse retinas. We found that APB differentially affected Off responses of RGCs in dark- and light-adapted mouse retinas. Under dark adaptation, while the APB-sensitive Off responses were blocked, APB increased the remaining Off responses (mainly from the secondary rod Off pathways) via removal of inhibition from On pathways to Off pathways. Under light adaptation, APB decreased Off responses. Glycinergic and GABAergic antagonists did not prevent the APB-induced reduction of Off responses of RGCs; however, a dopaminergic type 1 receptor (D(1)) blocker (SCH 23390) and a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker (ZD 7288) prevented the APB-induced reduction of Off responses of RGCs under light adaptation. The results indicated afunctional circuit: On cone bipolar cells to Off cone bipolar cells via D(1) receptors and HCN channels.

Hyaluronan Does Not Affect Bupivacaine's Inhibitory Action on Voltage-Gated Potassium Channel Activities in Bovine Articular Chondrocytes.

Objectives. The objective of this paper is to determine if hyaluronan affects bupivacaine's anesthetic function. Methods. Whole cell patch clamp recordings were performed on bovine articular chondrocytes cultured in 60 mm dishes. The chondrocytes were treated with phosphate-buffered saline (control group), 7.5 mg/mL hyaluronan (Orthovisc), 0.25% bupivacaine, or a mixture of 7.5 mg/mL hyaluronan and 0.25% bupivacaine. Outward currents were elicited by step depolarization from -90 mV to 150 mV with 5 mV increments and holding for 200 ms. Results. The amplitude of outward currents elicited at 150 mV was 607.1 ± 135.4 pA (mean ± standard error) in the chondrocytes treated with phosphate buffered saline, 550.0 ± 194.9 pA in the chondrocytes treated with hyaluronan, 18.4 ± 8.3 pA in the chondrocytes treated with bupivacaine, and 12.8 ± 2.6 pA in the chondrocytes treated with a mixture of hyaluronan and bupivacaine. Conclusion. Hyaluronan does not affect bupivacaine's inhibitory action on the potassium channel activities in bovine articular chondrocytes. This finding suggests that intra-articular injection of a mixture of hyaluronan and bupivacaine may not affect the anesthetic effects of bupivacaine.

Adipose-derived stem cells on hyaluronic acid-derived scaffold: a new horizon in bioengineered cornea.

OBJECTIVE: To evaluate the ability of human adipose-derived stem cells (h-ASCs) to survive and differentiate in corneal stroma. METHODS: Our experiment consisted of 2 phases. First, we cultured h-ASCs in different types of hyaluronic acid (HA)-derived synthetic extracellular matrixes (sECMs) to determine the capability of proliferation and survival of the cells in hydrogels. Second, h-ASCs were grown in plastic flasks, labeled with an intracytoplasmic membrane fluorescent molecule, transferred onto different types of sECMs or the native HA product, and then inserted into the corneal stroma of the rabbits. After 10 weeks, we assessed the viability of the stem cells and the expression of cornea-specific proteins. RESULTS: The in vitro study showed that the HyStem-HP hydrogel had the highest yield of cells (1.1 × 10(6)/mL) compared with other types of HA-derived sECMs culture media, and the cells grown in the HyStem-HP hydrogel appeared more elongated and fibroblastlike. The in vivo study demonstrated that the labeled h-ASCs could be identified in the stroma with any type of sECM. The HA-derived sECMs, particularly the HyStem-HP hydrogel, showed better survival and cell morphologic features compared with pure HA. Immunostaining of keratocan, aldehyde dehydrogenase, and type I collagen revealed that the stem cells had expressed human cornea-specific proteins. CONCLUSION: Human adipose-derived stem cells can be successfully grown on HA-derived sECMs in vivo and can express human cornea-specific proteins. CLINICAL RELEVANCE: Human ASCs on an HA-derived scaffold may be used as a source of keratocytes to regenerate extracellular matrix-like material in situations where the cornea stroma has been compromised.

[Analysis of condom use and its factors on female sex workers in Shandong province].

OBJECTIVE: This study was to investigate the condom use and its factors on sex workers in Shandong province, and to provide effective suggestions for AIDS prevention strategies and interventions. METHODS: From April to July in 2009, 4732 female sex workers were investigated through anonymous questionnaires from 11 cities which were selected based on the AIDS epidemic, geographic location, economic conditions in Shandong province. Serum samples were collected and antibodies were tested by ELISA and TPPA from 4641 people. RESULTS: 4732 female sex workers who were 15 - 58 years old were investigated and the majority belonged to the low age group (≤ 24 years old) which accounted for 61.5% (2912/4732). Among the 4732 female sex workers, the unmarried, the divorced, or the widowed females accounted for 72.8% (3441/4725) and 72.0% (3403/4726) of them were poorly educated.42.3% (1994/4719) of them were found from other provinces. The right answers for knowledge of AIDS accounted for 45.7% (2164/4732). 80.6% (3416/4236) of these females were found to used condoms in the most recent commercial sex activity. The rate of consistently using condoms in sex activity during the last month was 58.4% (2467/4221). In this survey, 7.3% (337/4637) of investigated females had been diagnosed with sexually transmitted diseases, 30.7% (1449/4726) of them had received HIV antibody test, 70.4% (3323/4732) of these people had received the AIDS intervention services, and 3.6% (167/4668) of them had ever used drug. Multivariate logistic regression analysis showed that high education level (junior high school or lower vs senior high school or higher, adjusted OR = 0.77, 95%CI: 0.67 - 0.90), having received the HIV intervention (received vs unreceived, adjusted OR = 1.36, 95%CI: 1.17 - 1.58), antibody detection (done vs not done, adjusted OR = 1.33, 95%CI: 1.15 - 1.55), and good knowledge about AIDS (low score group vs high score group, adjusted OR = 0.37, 95%CI: 0.32 - 0.44) were independent factors that increased safe sex behavior; while using drug (drug vs not drug, adjusted OR = 0.22, 95%CI: 0.15 - 0.31) was a negative factor. CONCLUSION: The prevalence rate of HIV infection among female sex workers was low in Shandong province. However, the low rate of condom use and the high prevalence of self-reported STD-related symptoms suggested that more attentions should be paid to the factors of risk behaviors, and more targeted interventions are critically needed.

The roles of ionotropic glutamate receptors along the On and Off signaling pathways in the light-adapted mouse retina.

Although the locations of glutamate receptors along the On and Off pathways have been determined, how these receptors modulate the retinal outputs--the light-evoked and spontaneous activities of individual ganglion cells--is not fully understood in the mouse retina. Specifically, how these receptors mediate On and Off responses of retinal ganglion cells in mouse retina under light adaptation remains unknown. Since mouse retina has become a powerful model for vision research, the functions of glutamate receptors along the On and Off pathways in mouse need to be determined. In the current study, the light-evoked and spontaneous excitatory postsynaptic currents (light-evoked EPSCs and sEPSCs) from On, Off and On-Off retinal ganglion cells (RGCs) were recorded using whole-cell patch-clamp recordings to assess how NMDA and AMPA/KA receptors modulate the retinal outputs of RGCs in the light-adapted mouse retina. We found NMDA and AMPA/KA played different roles in light-evoked EPSCs along On and Off pathways in light-adapted mice retinas. Both NMDA receptor antagonist DL-2-amino-5-phosphonopentanoic acid (AP-5) and AMPA/KA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) acted on RGCs to reduce On responses of ganglion cells while they acted on Off-cone bipolar cells and/or ganglion cells to mediate Off responses of RGCs. Co-application of AP-5 and CNQX completely eliminated the Off responses in majority of RGCs, indicating that both NMDA and AMPA/KA receptors are critical for light signaling along the cone-driven Off pathways in the light-adapted mouse retina.

Cell type-specific and light-dependent expression of Rab1 and Rab6 GTPases in mammalian retinas.

The Ras-like Rab1 and Rab6 GTPases modulate protein traffic along the early secretory pathway and are involved in the regulation of maturation of rhodopsin in the outer retina. However, Rab GTPases have not been studied in the inner retinas. Here, we analyzed the anatomatic distribution and expression of Rab1 and Rab6 in the mouse and rat retinas by immunohistochemistry and immunoblotting. We found that Rab1 was specifically expressed in the rod bipolar cells, while Rab6 was expressed in a different cell type(s) from rod bipolar cells in the inner retina. We also demonstrated that expression of Rab1 and Rab6 was increased with light. These data provided the first evidence implicating that Rab1 and Rab6 may be involved in the regulation of the retinal adaptation.

Inhibition of nitric oxide synthase desensitizes retinal ganglion cells to light by diminishing their excitatory synaptic currents under light adaptation.

The effect of inhibiting nitric oxide synthase (NOS) on the visual responses of mouse retinal ganglion cells (RGCs) was studied under light adaptation by using patch-clamp recordings. The results demonstrated that NOS inhibitor, l-NAME, reduced the sensitivity of RGCs to light under light adaptation at different ambient light conditions. These observations were seen in all cells that recordings were made from. l-NAME diminished the excitatory synaptic currents (EPSCs), rather than increasing the inhibitory synaptic currents, of RGCs to reduce the sensitivity of RGCs to light. Cones may be the sites that l-NAME acted to diminish the EPSCs of RGCs.

Differential effects of charybdotoxin on the activity of retinal ganglion cells in the dark- and light-adapted mouse retina.

Patch-clamp recordings were made from retinal ganglion cells in the mouse retina. Under dark adaptation, blockage of BK(Ca) channels increases the spontaneous excitatory postsynaptic currents (EPSCs) and light-evoked On-EPSCs, while it decreases the light-evoked Off inhibitory postsynaptic currents (IPSCs). However, under light adaptation it decreases the light-evoked On-EPSCs, the spontaneous IPSCs and the light-evoked On- and Off-IPSCs. Blockage of BK(Ca) channels significantly altered the outputs of RGCs by changing their light-evoked responses into a bursting pattern and increasing the light-evoked depolarization of the membrane potentials, while it did not significantly change the peak firing rates of light-evoked responses.

Epibatidine application in vitro blocks retinal waves without silencing all retinal ganglion cell action potentials in developing retina of the mouse and ferret.

Epibatidine (EPI), a potent cholinergic agonist, disrupts acetylcholine-dependent spontaneous retinal activity. Early patch-clamp recordings in juvenile ferrets suggested that EPI blocks all retinal ganglion cell (RGC) action potentials when applied to the retina. In contrast, recent experiments on the developing mouse that relied on multielectrode array (MEA) recordings reported that EPI application decorrelates the activity of neighboring RGCs and eliminates retinal waves while preserving the spiking activity of many neurons. The different techniques used in previous studies raise the question of whether EPI has different effects on RGC activity in mouse compared with that in ferret. A resolution of this issue is essential for interpreting the results of developmental studies that relied on EPI to manipulate retinal activity. Our goal was to compare the effects of EPI on the spontaneous discharges of RGCs in mouse and ferret using 60-electrode MEA as well as patch-clamp recordings during the developmental stage when retinal waves are driven by acetylcholine in both species. We found that in both mouse and ferret EPI decorrelates RGC activity and eliminates retinal waves. However, EPI does not block all spontaneous activity in either species. Instead, our whole cell recordings reveal that EPI silences more than half of all RGCs while significantly increasing the activity of the remainder. These results have important implications for interpreting the results of previous studies that relied on this cholinergic agonist to perturb retinal activity.

The sensitivity of light-evoked responses of retinal ganglion cells is decreased in nitric oxide synthase gene knockout mice.

We have shown previously that increasing the production of nitric oxide (NO) results in a dampening of visual responses of retinal ganglion cells (G. Y. Wang, L. C. Liets, & L. M. Chalupa, 2003). To gain further insights into the role of NO in retinal function, we made whole-cell patch clamp recordings from ganglion cells of neural type nitric oxide synthase (nNOS) gene knockout mice. Here we show that in the dark-adapted state, the sensitivity of retinal ganglion cell to light stimulation is decreased in nNOS knockout animals. The lowest light intensities required to evoke optimal responses and the average intensities that evoked half-maximal responses were significantly higher in nNOS knockouts than in normal mice. Retinal histology and other features of light-evoked responses of ganglion cells in nNOS mice appeared to be indistinguishable from those of normal mice. Collectively, these results, in conjunction with our previous work, provide evidence that increasing levels of NO dampen visual responses of ganglion cells, while a lack of nNOS decreases the sensitivity of these neurons to light. Thus, NO levels in the retina are capable of modulating the information that ganglion cells convey to the visual centers of the brain.

Unique functional properties of the APB sensitive and insensitive rod pathways signaling light decrements in mouse retinal ganglion cells.

Light decrements are mediated by two distinct groups of rod pathways in the dark-adapted retina that can be differentiated on the basis of their sensitivity to the glutamate agonist DL-2-amino-phosphonobutyric (APB). By means of the APB sensitive pathway, rods transmit light decrements via rod bipolar cells to AII amacrine cells, then to Off cone bipolar cells, which in turn innervate the dendrites of Off ganglion cells. APB hyperpolarizes rod bipolar cells, thus blocking this rod pathway. With APB insensitive pathways, rods either directly synapse onto Off cone bipolar cells, or rods pass light decrement signal to cones by gap junctions. In the present study, whole-cell patch-clamp recordings were made from ganglion cells in the dark-adapted mouse retina to investigate the functional properties of APB sensitive and insensitive rod pathways. The results revealed several clear-cut differences between the APB sensitive and APB insensitive rod pathways. The latency of Off responses to a flashing spot of light was significantly shorter for the APB insensitive pathways than those for the APB sensitive pathway. Moreover, Off responses of the APB insensitive pathways were found to be capable of following substantially higher stimulus frequencies. Nitric oxide was found to selectively block Off responses in the APB sensitive rod pathway. Collectively, these results provide evidence that the APB sensitive and insensitive rod pathways can convey different types of information signaling light decrements in the dark-adapted retina.

[Detecting multi-drug resistance of bladder cancer for the intravesical chemotherapy].

OBJECTIVE: To explore multi-drug resistance (MDR) of bladder cancer for the intravesical instillation. METHODS: Using immunohistochemical staining, in 44-case human bladder cancer cells, the expressions of P-glycoprotein (P-gp), glutathione S-transferase (GST-pi) and topoisomerase (TOPO-II), were detected to find out the resistance to drugs. RESULTS: P-gp had a higher expression in 54.5% cases. GST-pi had no or a lower expression in 65.9% cases. TOPO-II had a higher expression in 29.5% but a lower expression in 65.9% cases. CONCLUSION: Detecting the factors of MDR in bladder cancer cells could help to choose drugs for intravesical chemotherapy.

Spontaneous activity of morphologically identified ganglion cells in the developing ferret retina.

Whole-cell patch-clamp recordings were made from morphologically identified ganglion cells in the intact retina of developing ferrets. As early as 3 d after birth, all ganglion cells exhibited bursts of spontaneous activity, with the interval between bursts gradually decreasing with maturity. By 2 weeks after birth, ganglion cells could be morphologically differentiated into three major classes (alpha, beta, and gamma), and at this time each cell class was characterized by a distinct pattern of spontaneous activity. Dual patch-clamp recordings from pairs of neighboring cells revealed that cells of all morphological classes burst in a coordinated manner, regardless of cell type. These observations suggest that a common mechanism underlies the bursting patterns exhibited by all ganglion cell classes, and that class-specific firing patterns emerge coincident with retinal ganglion cell morphological differentiation.

Nitric oxide differentially modulates ON and OFF responses of retinal ganglion cells.

Several lines of evidence suggest that nitric oxide (NO) can regulate diverse retinal functions, but whether this gas is capable of modulating the visual responses of retinal output neurons has not been established. In the present study the effects of NO on rod-driven responses of retinal ganglion cells were tested by making whole cell patch-clamp recordings from morphologically identified ganglion cells in the isolated ferret retina. Bath application of L-arginine, the substrate of nitric oxide synthase, and S-nitroso-N-acetylpenicillamine, the NO donor, was found to differentially affect on and off discharge patterns. The introduction of these drugs significantly decreased visual responses of retinal ganglion cells, but the effects were more pronounced on off than on on discharges. The peak discharge rates of on responses were usually reduced by about 40%, but not completely blocked. In contrast, off responses were completely blocked in most cells. These differential effects were observed in on-off cells as well as in cells that yielded just on or off discharges. The off responses that were blocked by NO were also blocked by DL-2-amino-phosphonobutyric acid (APB) and strychnine, suggesting the involvement of the APB-sensitive rod pathway.