Predictive biomarkers for embryotoxicity: a machine learning approach to mitigating multicollinearity in RNA-Seq.

Multicollinearity, characterized by significant co-expression patterns among genes, often occurs in high-throughput expression data, potentially impacting the predictive model's reliability. This study examined multicollinearity among closely related genes, particularly in RNA-Seq data obtained from embryoid bodies (EB) exposed to 5-fluorouracil perturbation to identify genes associated with embryotoxicity. Six genes-Dppa5a, Gdf3, Zfp42, Meis1, Hoxa2, and Hoxb1-emerged as candidates based on domain knowledge and were validated using qPCR in EBs perturbed by 39 test substances. We conducted correlation studies and utilized the variance inflation factor (VIF) to examine the existence of multicollinearity among the genes. Recursive feature elimination with cross-validation (RFECV) ranked Zfp42 and Hoxb1 as the top two among the seven features considered, identifying them as potential early embryotoxicity assessment biomarkers. As a result, a t test assessing the statistical significance of this two-feature prediction model yielded a p value of 0.0044, confirming the successful reduction of redundancies and multicollinearity through RFECV. Our study presents a systematic methodology for using machine learning techniques in transcriptomics data analysis, enhancing the discovery of potential reporter gene candidates for embryotoxicity screening research, and improving the predictive model's predictive accuracy and feasibility while reducing financial and time constraints.

Rapid quantitative high-throughput mouse embryoid body model for embryotoxicity assessment.

Individuals are exposed to a wide arrays of hazardous chemicals on a daily basis through various routes, many of which have not undergone comprehensive toxicity assessments. While traditional developmental toxicity tests involving pregnant animals are known for their reliability, they are also associated with high costs and time requirements. Consequently, there is an urgent demand for alternative, cost-efficient, and rapid in vitro testing methods. This study aims to address the challenges related to automating and streamlining the screening of early developmental toxicity of chemicals by introducing a mouse embryoid body test (EBT) model in a 384-ultra low attachment well format. Embryoid bodies (EBs) generated in this format were characterized by a spontaneous differentiation trajectory into cardiac mesoderm by as analyzed by RNA-seq. Assessing prediction accuracy using reference compounds suggested in the ICH S5(R3) guideline and prior studies resulted in the establishment of the acceptance criteria and applicability domain of the EBT model. The results indicated an 84.38% accuracy in predicting the developmental toxicity of 23 positive and 9 negative reference compounds, with an optimized cutoff threshold of 750 µM. Overall, the developed EBT model presents a promising approach for more rapid, high-throughput chemical screening, thereby facilitating well-informed decision-making in environmental management and safety assessments.

Investigation of Potential Antioxidant, Thrombolytic and Neuropharmacological Activities of Homalomena aromatica Leaves Using Experimental and In Silico Approaches.

The leaves of Homalomena aromatica are traditionally used in Bangladesh for the treatment of different chronic ailments. The purpose of this study was to explore in vitro antioxidant, thrombolytic activities, and in vivo neuropharmacological effects of methanolic extract of Homalomena aromatica (MEHA) leaves. Antioxidant activity of MEHA was assessed by a DPPH free radical scavenging assay and total phenolics content, total flavonoids content were also measured. The thrombolytic activity was determined by percentage of clot lysis and neuropharmacological activities by hole board, tail suspension, forced swimming and elevated plus maze tests. The results showed that the IC50 value of the extract against DPPH was 199.51 µg/mL. Quantitative analysis displayed higher contents of phenolics and flavonoids (147.71 mg gallic acid equivalent/g & 66.65 mg quercetin equivalent/g dried extract, respectively). The extract also showed a significant clot lysis (33.31%) activity. In case of anxiolytic activity, the elevate plus maze (EPM) test demonstrated an increase in time spent in open arms, and in case of hole board test, the number of head dipping was also significantly increased (p < 0.05). All the test compared with control (1% Tween in water) and standard (diazepam 1 mg/kg), significant dose (200 & 400 mg/kg) dependent anxiolytic activity was found. In antidepressant activity, there was a significant decrease in period of immobility in both test models (tail suspension and forced swimming) (p < 0.05). Moreover, 13 compounds were identified as bioactive, showed good binding affinities to xanthine oxidoreductase, tissue plasminogen activator receptor, potassium channel receptor, human serotonin receptor targets in molecular docking experiments. Furthermore, ADME/T analysis revealed their drug-likeness, likely pharmacological actions and non-toxic upon consumption. Taken together, our finding support the traditional medicinal use of this plant, which may provide a potential source for future drug discovery.

In vitro synergistic potentials of novel antibacterial combination therapies against Salmonella enterica serovar Typhimurium.

BACKGROUND: The antibiotics generally used in farm animals are rapidly losing their effectiveness all over the world as bacteria develop antibiotic resistance. Like some other pathogenic bacteria multidrug-resistant strains of Salmonella enterica serovar Typhimurium (S. Typhimurium) are also frequently found in animals and humans which poses a major public health concern. New strategies are needed to block the development of resistance and to prolong the life of traditional antibiotics. Thus, this study aimed to increase the efficacy of existing antibiotics against S. Typhimurium by combining them with opportunistic phenolic compounds gallic acid (GA), epicatechin, epicatechin gallate, epigallocatechin and hamamelitannin. Fractional inhibitory concentration indexes (FICI) of phenolic compound-antibiotic combinations against S. Typhimurium were determined. Based on the FICI and clinical importance, 1 combination (GA and ceftiofur) was selected for evaluating its effects on the virulence factors of this bacterium. Viability of Rattus norvegicus (IEC-6) cell in presence of this antibacterial combination was evaluated. RESULTS: Minimum inhibitory concentrations (MICs) of GA, epigallocatechin and hamamelitannin found against different strains of S. Typhimurium were 256, (512-1024), and (512-1024) µg/mL, respectively. Synergistic antibacterial effect was obtained from the combination of erythromycin-epicatechin gallate (FICI: 0.50) against S. Typhimurium. Moreover, additive effects (FICI: 0.502-0.750) were obtained from 16 combinations against this bacterium. The time-kill assay and ultrastructural morphology showed that GA-ceftiofur combination more efficiently inhibited the growth of S. Typhimurium compared to individual antimicrobials. Biofilm viability, and swimming and swarming motilities of S. Typhimurium in presence of GA-ceftiofur combination were more competently inhibited than individual antimicrobials. Viabilities of IEC-6 cells were more significantly enhanced by GA-ceftiofur combinations than these antibacterials alone. CONCLUSIONS: This study suggests that GA-ceftiofur combination can be potential medication to treat S. Typhimurium-associated diarrhea and prevent S. Typhimurium-associated blood-stream infections (e.g.: fever) in farm animals, and ultimately its transmission from animal to human. Further in vivo study to confirm these effects and safety profiles in farm animal should be undertaken for establishing these combinations as medications.

Pharmacokinetic and pharmacodynamic integration for optimal dosage of cefquinome against Streptococcus equi subsp. equi in foals.

Cefquinome is administered in horses for the treatment of respiratory infection caused by Streptococcus equi subsp. zooepidemicus, and septicemia caused by Escherichia coli. However, there have been no attempts to use cefquinome against Streptococcus equi subsp. equi (S. equi), the causative agent of strangles. Hence the objective of this study was to calculate an optimal dosage of cefquinome against S. equi based on pharmacokinetics and pharmacodynamics integration. Cefquinome (1.0 mg/kg) was administered by intravenous and intramuscular routes to six healthy thoroughbred foals. Serum cefquinome concentrations were determined by high-performance liquid chromatography. The in vitro and ex vivo antibacterial activity were determined from minimum inhibitory concentrations (MIC) and bacterial killing curves. The optimal dosage was calculated from the integration of pharmacokinetic parameters and area under the curve (AUC24h/MIC) values. Total body clearance and volume of distribution of cefquinome after intravenous administration were 0.06 L/h/kg and 0.09 L/kg, respectively. Following intramuscular administration, a maximum concentration of 0.73 µg/mL at 1.52 h (Tmax) and a systemic bioavailability of 37.45% were observed. The MIC of cefquinome against S. equi was 0.016 µg/mL. The ex vivo AUC24h/MIC values representing bacteriostatic, and bactericidal activity were 113.11, and 143.14 h, respectively. Whereas the %T > MIC for bactericidal activity was 153.34%. In conclusion, based on AUC24h/MIC values and pharmacokinetic parameters, cefquinome when administered by intramuscularly at a dosage of 0.53 mg/kg every 24 h, would be effective against infection caused by S. equi in foals. Further studies may be necessary to confirm its therapeutic efficacy in a clinical environment.

Tylosin exposure reduces the susceptibility of Salmonella Typhimurium to florfenicol and tetracycline.

BACKGROUND: Antibiotics exposure has been implicated in the emergence of bacterial strains that are resistant to structurally related or unrelated antibiotics. Tylosin is a macrolide antibiotic that has been administered to treat respiratory pathogenic bacteria in swine. Thus, this study was undertaken to evaluate the impact of exposure to a constant (3 µg/mL) and decreasing concentrations of tylosin on the susceptibility of Salmonella enterica serovar Typhimurium to various antibiotics. RESULTS: S. Typhimurium strains exposed to tylosin for 12 and 24 h in the in vitro dynamic model demonstrated at least an eight-fold increase in the minimum inhibitory concentrations (MICs) of florfenicol and tetracycline. Exposure to tylosin extended the lag-time of the growth curve and enhanced the generation of reactive oxygen species. Gene expression analysis demonstrated up-regulation of the acrAB and tolC Salmonella efflux pump genes and its global regulators (marA and soxS). Besides, the expression of ompC gene was down-regulated in tylosin exposed S. Typhimurium. CONCLUSION: Exposure to decreasing concentrations of tylosin could reduce the susceptibility of S. Typhimurium to florfenicol and tetracycline.

Pharmacokinetics, tissue residues, and ex vivo pharmacodynamics of tylosin against Mycoplasma anatis in ducks.

The pharmacokinetics of tylosin were investigated in 3 groups of ducks (n = 6). They received a single dose of tylosin (50 mg/kg) by intravenous (IV), intramuscular (IM), and oral administrations, respectively. Plasma samples were collected at various time points to 24 hr post-administration to evaluate tylosin concentration over time. Additionally, tylosin residues in tissues and its withdrawal time were assessed using 30 ducks which received tylosin orally (50 mg/kg) once daily for 5 consecutive days. After IV administration, the volume of distribution, elimination half-life, area under the plasma concentration-time curve, and the total body clearance were 7.07 ± 1.98 L/kg, 2.04 hr, 19.47 µg hr/ml, and 2.82 L hr-1  kg-1 , respectively. After IM and oral administrations, the maximum plasma concentrations were 3.70 and 2.75 µg/ml achieved at 1 and 2 hr, and the bioavailability was 93.95% and 75.77%, respectively. The calculated withdrawal periods of tylosin were 13, 8, and 5 days for kidney, liver, and muscle, respectively. For the pharmacodynamic profile, the minimum inhibitory concentration for tylosin against M. anatis strain 1,340 was 1 µg/ml. The calculated optimal oral dose of tylosin against M. anatis in ducks based on the ex vivo pharmacokinetic/pharmacodynamic modeling was 61 mg kg-1  day-1 .

Antimicrobial resistance and genetic characterization of coagulase-negative staphylococci from bovine mastitis milk samples in Korea.

Coagulase-negative staphylococci (CNS) are one of the most common bovine mastitis pathogens found worldwide. In this study, we investigated the prevalence and distribution of CNS species in mastitis milk samples and further characterized the methicillin-resistant (MR) CNS. A total of 311 CNS were isolated from 3,692 quarter milk samples from 1,373 dairy cattle at 81 farms between 2013 and 2017. Further evaluation of the CNS isolates revealed 14 CNS species among the samples and 3 predominant species-namely, Staphylococcus chromogenes, Staphylococcus simulans, and Staphylococcus epidermidis. Resistance was higher in S. epidermidis than in other CNS species except for resistance against oxacillin in Staphylococcus sciuri. Resistance to ß-lactams was the most common in all CNS species (8.4% in ampicillin, 21.2% in oxacillin, and 13.5% in penicillin). Conversely, only minimal resistance to cephalothin, ceftiofur, and pirlimycin/novobiocin was found. Twenty-one isolates from 4 species were mecA-carrying MRCNS strains, including 18 S. epidermidis and 1 each of S. sciuri, Staphylococcus equorum, and Staphylococcus hominis. The majority of the mecA-carrying MRCNS isolates were produced in the biofilm. Furthermore, multidrug-resistant sequence type 179 isolate produced the strongest biofilm. Seven genotypes were detected in the 18 MR S. epidermidis strains, the most predominant of which persisted on a farm for 2 yr. Our findings for the antimicrobial susceptibility profiles and genotypic characterization of the MRCNS isolates could provide valuable information for controlling the spread of resistance and the selection of appropriate antimicrobial therapies for mastitis in the future. Further, strategic antibiotic use for mastitis treatment and hygienic management practices aimed at the prevention of the growth of resistant bacteria are urgently needed on dairy farms.

Preventive effects of a novel herbal mixture on atopic dermatitis-like skin lesions in BALB/C mice.

BACKGROUND: A combination of parts of Cornus officinalis, Rosa multiflora, Lespedeza bicolor, Platycladus orientalis, and Castanea crenata is commonly used for alleviating inflammatory skin disorders. Therefore, this study was carried out to evaluate the in vitro and in vivo preventive effects of a novel herbal formula made from the five plants (C2RLP) against atopic dermatitis in BALB/C mice. METHODS: Mice were allocated into five groups (n = 8) including, control (Normal, petrolatum, and betamethasone treated) and treatment groups (treated with 2.5 and 5% C2RLP ointment). Atopic lesion was induced by applying 1-Chloro-2, 4-dinitrobenzene to the dorsal thoracic area of mice. Macroscopical and histological evaluations were performed to determine the effects of treatment on the progress of the skin lesions. The effects of treatment on the production and release of interleukins, interferon -ϒ, nitrite, prostaglandin E2, thymus and activation-receptor chemokine, and ß-hexosaminidase were evaluated and comparisons were made between groups. In addition, the chemical compounds present in C2RLP were identified by Liquid Chromatography-Mass Spectrometry. RESULTS: Topical application of C2RLP reduced the dermatitis score and suppressed histopathological changes in mice. Treatment significantly reduced (P < 0.05) plasma IL-4 level, the production of nitrite, prostaglandin E2, and thymus and activation-receptor chemokine production. The lipopolysaccharide-induced iNOS-mRNA expression in RAW 264.7 cells was also suppressed by high concentrations of C2RLP. In addition, C2RLP showed an inhibitory effect against DPPH free radical (IC50 = 147.5 µg/ml) and ß-hexosaminidase release (IC50 = 179.5 µg/ml). Liquid Chromatography-Mass Spectrometry analysis revealed the presence of various compounds, including loganin, ellagic acid, and kaempferol 3-glucoside. CONCLUSION: Down-regulation of T- helper 2 cellular responses and suppression of inflammatory mediators contributed to the protective effects of C2RLP from atopic dermatitis in BALB/C mice.

Inhibition of Salmonella Typhimurium adhesion, invasion, and intracellular survival via treatment with methyl gallate alone and in combination with marbofloxacin.

Salmonella enterica serovar Typhimurium infects intestinal epithelia and macrophages, which is prevented by inhibiting adhesion and cell invasion. This study aimed to investigate the role of methyl gallate (MG) in adhesion, invasion, and intracellular survival of Salmonella Typhimurium in Caco-2 and RAW 264.7 cells via a gentamicin protection assay, confocal microscopy, and quantitative reverse-transcription polymerase chain reaction. MG (30 µg/mL) inhibited adhesion and invasion of Salmonella Typhimurium by 54.01% and 60.5% in RAW 264.7 cells, respectively. The combination of MG with sub-minimum inhibitory concentration (MIC) of marbofloxacin (MRB) inhibited the adhesion, invasion, and intracellular survival by 70.49%, 67.36%, and 74%, respectively. Confocal microscopy further revealed reductions in bacterial count in Caco-2 cells treated with MG alone or with sub-MIC of MRB. Furthermore, MG alone or in combination with sub-MIC of MRB decreased the motility of Salmonella Typhimurium. Quorum sensing genes including sdiA, srgE, and rck were downregulated by 52.8%, 61.7%, and 22.2%, respectively. Moreover, rac-1 was downregulated by 56.9% and 71.9% for MG alone and combined with sub-MIC of MRB, respectively, in mammalian cells. Furthermore, MG downregulated virulence genes of Salmonella Typhimurium including cheY, ompD, sipB, lexA, and ompF by 59.6%, 60.2%, 20.5%, 31.4%, and 16.2%, respectively. Together, the present results indicate that MG alone or in combination with a sub-MIC of MRB effectively inhibited the adhesion, invasion, and intracellular survival of Salmonella Typhimurium in vitro by downregulating quorum sensing and virulence genes.

An in vivo immunomodulatory and anti-inflammatory study of fermented Dendropanax morbifera Léveille leaf extract.

BACKGROUND: Medicinal plants represent a source of new drugs for the prevention and treatment of infectious diseases. Dendropanax morbifera Léveille is an economically and medicinally important subtropical tree that has various biological activities. However, its ability to affect immune responses in vivo is unknown. Hence, this study was designed to examine the immunomodulatory activity of fermented D. morbifera extract in BALB/c mice. METHODS: five-week-old female BALB/c mice were arranged in six groups and kept under a standard laboratory condition. Splenocyte counts were determined using the trypan blue dye exclusion method, and splenic lymphocyte proliferation was determined using concanavalin A and lipopolysaccharide (LPS). Flow cytometric analysis was performed to phenotype T-lymphocytes. Next, cytokine and immunoglobulin quantitation was performed using sandwich ELISA. RESULTS: The results showed an increase in spleen cells by 71 and 67% in mice treated with 125 and 250 mg/kg of D. morbifera, respectively. In addition, splenocyte proliferation was increased 58.7% in response to concanavalin A treatment, while LPS treatment induced a 73.3% increase in mice treated with 125 mg/kg. T-cell phenotypic analysis indicated that D. morbifera-treated groups showed higher CD8a+, CD11b and CD3+ T-cell expression. However, the treatment groups showed suppression of IL-1α, Il-1ß and IL-4. In addition, the IgG super-family was downregulated in a dose-dependent manner by 4.5% up to 43.7%. CONCLUSIONS: Taken together, we show that D. morbifera increases the number and proliferation of T- and B-lymphocytes. Moreover, these effects may play a role in boosting non-specific immunity, while suppressing proinflammatory cytokines and immunoglobulins after a single antigen exposure.

Using In Vitro Dynamic Models To Evaluate Fluoroquinolone Activity against Emergence of Resistant Salmonella enterica Serovar Typhimurium.

The objectives of this study were to determine pharmacokinetic/pharmacodynamic (PK/PD) indices of fluoroquinolones that minimize the emergence of resistant Salmonella enterica serovar Typhimurium (S Typhimurium) using in vitro dynamic models and to establish mechanisms of resistance. Three fluoroquinolones, difloxacin (DIF), enrofloxacin (ENR), and marbofloxacin (MAR), at five dose levels and 3 days of treatment were simulated. Bacterial killing-regrowth kinetics and emergence of resistant bacteria after antibacterial drug exposure were quantified. PK/PD indices associated with different levels of antibacterial activity were computed. Mechanisms of fluoroquinolone resistance were determined by analyzing target mutations in the quinolone resistance-determining regions (QRDRs) and by analyzing overexpression of efflux pumps. Maximum losses in susceptibility of fluoroquinolone-exposed S Typhimurium occurred at a simulated AUC/MIC ratio (area under the concentration-time curve over 24 h in the steady state divided by the MIC) of 47 to 71. Target mutations in gyrA (S83F) and overexpression of acrAB-tolC contributed to decreased susceptibility in fluoroquinolone-exposed S Typhimurium. The current data suggest AUC/MIC (AUC/mutant prevention concentration [MPC])-dependent selection of resistant mutants of S Typhimurium, with AUC/MPC ratios of 69 (DIF), 62 (ENR), and 39 (MAR) being protective against selection of resistant mutants. These values could not be achieved in veterinary clinical areas under the current recommended therapeutic doses of the fluoroquinolones, suggesting the need to reassess the current dosing regimen to include both clinical efficacy and minimization of emergence of resistant bacteria.

Immunomodulation of Lactobacillus pentosus PL11 against Edwardsiella tarda infection in the head kidney cells of the Japanese eel (Anguilla japonica).

Wild and farm-raised fish can be simultaneously exposed to different types of pathogens in their habitats. Hence, it is important to study their effects, whether isolated or in combination. Therefore, the aim of this study was to evaluate the effects of Lactobacillus pentosus PL11 on the transcription of specific cytokine genes related to immune response, using Japanese eel macrophages as an in vitro model. Head kidney leukocytes were isolated from Japanese eels and cell viability was determined using an MTT reagent. In addition, the Griess reagent was used to determine the nitric oxide (NO) production while, an enzyme-linked immunosobent assay (ELISA) and a quantitative polymerase chain reaction (qPCR) were utilized to quantify the level of proinflammatory cytokines. The results of the study indicated that infection by Edwardsiella tarda alone causes a higher rate of cell death and an increase in the production of proinflammatory cytokines, such as interleukin-1ß (IL-1ß, 822.67 ± 29.48 pg mL(-1)), interleukin-6 (IL-6, 13.57 ± 0.55 pg mL(-1)), and tumor necrosis factor-α (TNF-α, 2033.67 ± 84.68 pg mL(-1)). However, co-culture with L. pentosus PL11 downregulates the production of NO and the related IL-1ß, IL-6, and TNF-α by 46%, 88.4%, 59%, and 77%, respectively. Quantification of the mRNA expression level revealed it to be consistent with the ELISA analysis. Hence, we infer that L. pentosus PL11 plays a significant role in the immunmodulation of the inflammatory responses that arise in fish owing to infection by pathogenic bacteria such as Edwardsiella tarda.

Pharmacokinetics, pharmacokinetic-pharmacodynamic relationship, and withdrawal period of amoxicillin sodium in olive flounder (Paralichthys olivaceus).

1. The pharmacokinetics (PK) and withdrawal period of amoxicillin sodium in olive flounder and its activity against pathogenic bacteria of olive flounder were investigated. 2. Intramuscular administration (12.5 or 125 mg/kg, n = 160) and HPLC analysis of sera were used. 3. Rapid absorption (Tmax 2.6 and 2.2 h), prolonged action (terminal half-life, 15.52 and 10.42 h; MRT, 18.79 and 14.44 h), and dose-proportional exposure (AUC0-∞, 273.69 and 2755.37 h. µg/ml) were observed after 12.5 and 125 mg/kg doses. 4. The withdrawal period of amoxicillin sodium from muscle plus skin of olive flounder (n =40, water temperature, 23 °C) was 12 d (276 degree days). 5. Amoxicillin sodium had small MICs against Streptococcus iniae (0.008-0.06 µg/ml) and Streptococcus parauberis (0.03-1.0 µg/ml), whereas higher concentrations were required to inhibit Edwardsiella tarda isolates (0.06-16 µg/ml). 6. While large AUC0-24 h/MIC90 and Cmax/MIC90 ratios were obtained for S. iniae and S. parauberis, with drug concentrations in serum greater than MICs for the entire dosing interval (T > MIC90 of 100%), the lower dose (12.5 mg/kg) could not achieve target values of the PK-pharmacodynamic (PD) indices for E. tarda isolates, suggesting the need for higher doses to combat pathogenic bacteria with large MICs.

BaeR protein acts as an activator of nuclear factor-kappa B and Janus kinase 2 to induce inflammation in murine cell lines.

BaeR, a response regulator protein, takes part in multidrug efflux, bacterial virulence activity, and other biological functions. Recently, BaeR was shown to induce inflammatory responses by activating the mitogen-activated protein kinases (MAPKs). In this study, we investigated additional pathways used by BaeR to induce an inflammatory response. BaeR protein was purified from Salmonella enterica Paratyphi A and subcloned into a pPosKJ expression vector. RAW 264.7 cells were treated with BaeR, and RNA was extracted by TRIzol reagent for RT-PCR. Cytokine gene expression was analyzed by using the comparative cycle threshold method, while western blotting and ELISA were used to assess protein expression. We confirmed that BaeR activates nuclear factor-kappa B (NF-κB), thereby inducing an inflammatory response and increases the production of interleukins (IL-)1ß and IL-6. During this process, the Janus kinase 2 (JAK2)-STAT1 signaling pathway was activated, resulting in an increase in the release of interferons I and II. Additionally, COX-2 was activated and its expression increased with time. In conclusion, BaeR induced an inflammatory response through activation of NF-κB in addition to the MAPKs. Furthermore, activation of the JAK2-STAT1 pathway and COX-2 facilitated the cytokine binding activity, suggesting an additional role for BaeR in the modulation of the immune system of the host and the virulence activity of the pathogen.

Pharmacokinetics and pharmacokinetic/pharmacodynamic integration of marbofloxacin after intravenous and intramuscular administration in beagle dogs.

1.The aim of the present study was to determine the PKs of marbofloxacin in beagle dogs after intravenous (i.v.) and intramuscular (i.m.) administration, the ex vivo and in vitro PK/PD indices of marbofloxacin against clinical isolates of Staphylococcus pseudintermedius, and the ex vivo AUC/MIC ratios associated with different levels of antibacterial activity. 2.After i.v. of marbofloxacin (2 mg/kg), the mean ± SEM values of AUC, t1/2ß, Vss, and CL were 8.47 ± 3.51 h µg/mL, 8.08 ± 6.25 h, 2.32 ± 1.00 L/kg and 0.23 ± 0.06 L/kg/h and corresponding values after intramuscular injection were 11.37 ± 3.07 h µg/mL, 7.51 ± 3.70, 1.80 ± 0.90 L/kg and 0.17 ± 0.04 L/kg/h. After i.m. administration, a Cmax of 1.76 ± 0.09 µg/mL was achieved at Tmax of 0.47 ± 0.08 h. The ex-vivo AUC/MIC ratios required to produce bacteriostasis, bactericidal action and elimination of S. pseudintermedius were 65.03, 97.02 and 136.84 h. 3.The in vivo AUC/MIC ratios obtained after i.v. and i.m. administration of 2 mg/kg marbofloxacin (67.76 ± 1.23 and 91.18 ± 2.61) were below the ex vivo AUC/MIC ratios required for bactericidal activity and bacterial elimination (97.02 ± 9.24 2 mg/kg and 136.21 ± 7.58), suggesting that the recommended daily dosage (2 mg/kg) may not suffice to kill and eradicate S. pseudintermedius strains encountered in clinical area.

Ameliorative effects of pine bark extract on spermatotoxicity by α-chlorohydrin in rats.

We investigated the protective effects of pine bark extract (Pycnogenol®, PYC, Horphag Research Ltd., Route de Belis, France) against α-chlorohydrin (ACH)-induced spermatotoxicity in rats. Rats were orally administered ACH (30 mg/kg/day) with or without PYC (20 mg/kg/day) for 7 days. Administration of ACH significantly decreased sperm motility. α-Chlorohydrin also caused histopathological alterations and apoptotic changes in caput epididymides. An increased malondialdehyde concentration and decreased glutathione content, as well as catalase and glutathione peroxidase activities were also found. In contrast, PYC treatment significantly prevented ACH-induced spermatotoxicity, including decreased sperm motility, histopathological lesions, and apoptotic changes in the caput epididymis. Pycnogenol® also had an antioxidant benefit by decreasing malondialdehyde and increasing levels of the antioxidant glutathione and the activities of the antioxidant enzymes catalase and peroxidase in epididymal tissues. These results indicate that PYC treatment attenuated ACH-induced spermatotoxicity through antioxidant and antiapoptotic effects.

Putative drug and vaccine target protein identification using comparative genomic analysis of KEGG annotated metabolic pathways of Mycoplasma hyopneumoniae.

In the present study, a computational comparative and subtractive genomic/proteomic analysis aimed at the identification of putative therapeutic target and vaccine candidate proteins from Kyoto Encyclopedia of Genes and Genomes (KEGG) annotated metabolic pathways of Mycoplasma hyopneumoniae was performed for drug design and vaccine production pipelines against M.hyopneumoniae. The employed comparative genomic and metabolic pathway analysis with a predefined computational systemic workflow extracted a total of 41 annotated metabolic pathways from KEGG among which five were unique to M. hyopneumoniae. A total of 234 proteins were identified to be involved in these metabolic pathways. Although 125 non homologous and predicted essential proteins were found from the total that could serve as potential drug targets and vaccine candidates, additional prioritizing parameters characterize 21 proteins as vaccine candidate while druggability of each of the identified proteins evaluated by the DrugBank database prioritized 42 proteins suitable for drug targets.

Pharmacokinetic interaction of enrofloxacin/trimethoprim combination following single-dose intraperitoneal and oral administration in rats.

The pharmacokinetic interaction of enrofloxacin and trimethoprim was evaluated after single-dose intraperitoneal or oral co-administration in rats. Plasma concentrations of the two drugs were determined by high-performance liquid chromatography. Following intraperitoneal combination, a significant (P < 0.05) increase in mean values of plasma half-life (t 1/2) and maximum plasma concentration (C max) was observed for enrofloxacin and trimethoprim, respectively. There was a significant (P < 0.05) increase in mean values of area under the plasma drug concentration versus time from time zero to infinity (AUC0-∞) and C max between combined oral doses (10, 30 and 100 mg/kg) of both antibacterial drugs. Also, after oral conjugation a significant difference in mean values of MRT0-∞ was observed between lower (10 mg/kg) and higher (100 mg/kg) doses of both drugs. A significant increase in pharmacokinetic parameters of both drugs in combined intraperitoneal and oral doses indicated pharmacokinetic interaction of enrofloxacin and trimethoprim. Further study is recommended in other species of animals.

Comparative Pharmacokinetics of Gentamicin C1, C1a and C2 in Healthy and Infected Piglets.

Gentamicin, an aminoglycoside antibiotic, is a mixture of therapeutically active C1, C1a, C2 and other minor components. Despite its decades-long use in pigs and other species, its intramuscular (IM) pharmacokinetics/pharmacodynamics (PKs/PDs) are unknown in piglets. Furthermore, the PKs of many drugs differ between healthy and sick animals. Therefore, we investigated the PKs of gentamicin after a single IM dose (10 mg/kg) in healthy piglets and piglets that were intranasally co-infected with Actinobacillus pleuropneumoniae and Pasteurella multocida (PM). The plasma concentrations were measured using validated liquid chromatography/mass spectrometry. The gentamicin exposure was 36% lower based on the area under the plasma concentration-time curve and 16% lower based on the maximum plasma concentration (Cmax) in the infected piglets compared to the healthy piglets, while it was eliminated faster (shorter half-life and larger clearance) in the infected piglets compared to the healthy piglets. The clearance and volume of distribution were the highest for the C1 component. C1, C1a and C2 accounted for 22-25%, 33-37% and 40-42% of the total gentamicin exposure, respectively. The PK/PD target for the efficacy of aminoglycosides (Cmax/minimum inhibitory concentration (MIC) > 10) could be exceeded for PM, with a greater magnitude in the healthy piglets. We suggest integrating this PK information with antibiotic susceptibility data for other bacteria to make informed antibiotic and dosage regimen selections against piglet infections.