RP-LC method for simultaneous determination of sulfamethoxazole and trimethoprim content in veterinary drugs

This study describes the development of a method for simultaneous analysis of sulfamethoxazole (SMX) and trimethoprim (TMP) through the use of high-performance liquid chromatography/ultraviolet detector, with the application to veterinary medicines. Satisfactory chromatographic separation of SMX and TMP was isocratically with a C18 column (150 x 4.6 mm, 5 mm). A mobile phase consisting of water, pH 3.5, and methanol (60:40, v/v) was delivered at a flow rate of 1.0 mL min-1 for five minutes and then, increased to 1.8 mL min-1. Detection of the drugs was performed at 213 and 230 nm. Linearity was demonstrated in the range of 5 to 70 mg mL-1 for SMX and 1 to 30 mg mL-1 for TMP (r2 ≥ 0.99 for both compounds). The relative standard deviation was ≤ 5%, and the comparison of the results with the concentrations reported on the drug labels indicated that the quantification was accurate. The resultant stressed samples were analysed by the method. The proposed method shows great potential for simultaneous analysis of the drugs evaluated and represents a new alternative approach to quality control of veterinary medicines.

Contraceptive choices pre and post pregnancy in adolescence

STUDY OBJECTIVE

The main aim of this study is to evaluate the impact of adolescent pregnancy in the future contraceptive choices. A secondary aim is to verify whether these choices differ from those made after an abortion.

DESIGN

Retrospective study.

SETTING

Adolescent Unit of a tertiary care center.

PARTICIPANTS

212 pregnant teenagers.

INTERVENTIONS

Medical records review.

MAIN OUTCOME MEASURES

Intended pregnancy rate and contraceptive methods used before and after pregnancy. For contraceptive choices after pregnancy we considered: Group 1--teenagers who continued their pregnancy to delivery (n = 106) and Group 2--the same number of adolescents who chose to terminate their pregnancy.

RESULTS

The intended pregnancy rate was 14.2%. Prior to a pregnancy continued to delivery, the most widely used contraceptive method was the male condom (50.9%), followed by oral combined contraceptives (28.3%); 18.9% of adolescents were not using any contraceptive method. After pregnancy, contraceptive implant was chosen by 70.8% of subjects (P < .001) and the oral combined contraceptives remained the second most frequent option (17.9%, P = .058). Comparing these results with Group 2, we found that the outcome of the pregnancy was the main factor in the choices that were made. Thus, after a pregnancy continued to delivery, adolescents prefer the use of LARC [78.4% vs 40.5%, OR: 5,958 - 95% (2.914-12.181), P < .001)], especially contraceptive implants [70.8% vs 38.7%, OR: 4.371 - 95% (2.224-8.591), P < .001], to oral combined contraceptives [17.9% vs 57.5%, OR: 0.118 - 95% CI (0.054-0.258), P < .001].

CONCLUSION

Adolescent pregnancy and its outcome constitute a factor of change in future contraceptive choice.

Protective effect of leptin and ghrelin against toxicity induced by amyloid-β oligomers in a hypothalamic cell line

In addition to cognitive decline, Alzheimer's disease (AD) patients also exhibit an unexplained weight loss that correlates with disease progression. In young and middle-aged AD patients, large amounts of amyloid-β (Aβ) deposits were observed in the hypothalamus, a brain region involved in the control of feeding and body weight through the action of peripheral metabolic peptides, which have recently been shown to have neuroprotective effects. Moreover, levels of peripheral metabolic peptides, such as leptin and ghrelin, are changed in AD patients. The present study aimed to investigate the role of Aβ peptide in the survival of hypothalamic cells and to explore the receptor-mediated protective effect of leptin and ghrelin against Aβ-induced toxicity in these cells. Using the mHypoE-N42 cell line, we demonstrated for the first time that oligomeric Aβ is toxic to hypothalamic cells, leading to cell death. It was also demonstrated that leptin and ghrelin protect these cells against AβO-induced cell death through the activation of the leptin and ghrelin receptors, respectively. Furthermore, ghrelin and leptin prevented superoxide production, calcium rise and mitochondrial dysfunction triggered by AβO. Taken together, these results suggest that peripheral metabolic peptides, in particular leptin and ghrelin, might be considered as preventive strategies for ameliorating hypothalamic alterations in AD.

Immunogenic calreticulin exposure occurs through a phylogenetically conserved stress pathway involving the chemokine CXCL8

The exposure of calreticulin (CRT) on the surface of stressed and dying cancer cells facilitates their uptake by dendritic cells and the subsequent presentation of tumor-associated antigens to T lymphocytes, hence stimulating an anticancer immune response. The chemotherapeutic agent mitoxantrone (MTX) can stimulate the peripheral relocation of CRT in both human and yeast cells, suggesting that the CRT exposure pathway is phylogenetically conserved. Here, we show that pheromones can act as physiological inducers of CRT exposure in yeast cells, thereby facilitating the formation of mating conjugates, and that a large-spectrum inhibitor of G protein-coupled receptors (which resemble the yeast pheromone receptor) prevents CRT exposure in human cancer cells exposed to MTX. An RNA interference screen as well as transcriptome analyses revealed that chemokines, in particular human CXCL8 (best known as interleukin-8) and its mouse ortholog Cxcl2, are involved in the immunogenic translocation of CRT to the outer leaflet of the plasma membrane. MTX stimulated the production of CXCL8 by human cancer cells in vitro and that of Cxcl2 by murine tumors in vivo. The knockdown of CXCL8/Cxcl2 receptors (CXCR1/Cxcr1 and Cxcr2) reduced MTX-induced CRT exposure in both human and murine cancer cells, as well as the capacity of the latter-on exposure to MTX-to elicit an anticancer immune response in vivo. Conversely, the addition of exogenous Cxcl2 increased the immunogenicity of dying cells in a CRT-dependent manner. Altogether, these results identify autocrine and paracrine chemokine signaling circuitries that modulate CRT exposure and the immunogenicity of cell death.

Autophagy inhibition radiosensitizes in vitro, yet reduces radioresponses in vivo due to deficient immunogenic signalling

Clinical oncology heavily relies on the use of radiotherapy, which often leads to merely transient responses that are followed by local or distant relapse. The molecular mechanisms explaining radioresistance are largely elusive. Here, we identified a dual role of autophagy in the response of cancer cells to ionizing radiation. On one hand, we observed that the depletion of essential autophagy-relevant gene products, such as ATG5 and Beclin 1, increased the sensitivity of human or mouse cancer cell lines to irradiation, both in vitro (where autophagy inhibition increased radiation-induced cell death and decreased clonogenic survival) and in vivo, after transplantation of the cell lines into immunodeficient mice (where autophagy inhibition potentiated the tumour growth-inhibitory effect of radiotherapy). On the other hand, when tumour proficient or deficient for autophagy were implanted in immunocompetent mice, it turned out that defective autophagy reduced the efficacy of radiotherapy. Indeed, radiotherapy elicited an anti-cancer immune response that was dependent on autophagy-induced ATP release from stressed or dying tumour cells and was characterized by dense lymphocyte infiltration of the tumour bed. Intratumoural injection of an ecto-ATPase inhibitor restored the immune infiltration of autophagy-deficient tumours post radiotherapy and improved the growth-inhibitory effect of ionizing irradiation. Altogether, our results reveal that beyond its cytoprotective function, autophagy confers immunogenic properties to tumours, hence amplifying the efficacy of radiotherapy in an immunocompetent context. This has far-reaching implications for the development of pharmacological radiosensitizers.

QuEChERS-HPLC-DAD method for sulphonamides in chicken breast

The development of a QuEChERS-HPLC-DAD method using a Lichrospher 60 RP-Select B column (250 x 4.6 mm x 5 µm) at 40ºC, mobile phase constituted by phosphate buffer:acetonitrile (75:25, v/v) at a initial flow rate of 0.5 mL min-1, increased by 1.2 mL min-1 and at 265 nm is presented for simultaneous determination of sulphadiazine, sulphametoxipiridazine and sulphamethoxazole in chicken breast samples. QuEchERS is inexpensive, fast and easy, and the extraction of the analytes of the matrix was successfully employed. In addition, the method presented linearity, in the range of 25, 50, 100, 150, 175, and 200 µg kg-1, precision, selectivity and sensitivity. The intraday precision (RSD %) for QuEChERS method was between 3.6-10.8 (SDZ), 6.9-14.1 (SPZ) and 1.9-10.9 (SMX) and interday precision (RSD%) was between 1.5-9.7, 1.7-4.1 and 2.1-10.2, respectively. Results of accuracy (bias) were in the range of -8.6 to +11.9 %. Therefore, the validated method is clearly useful for the practical residue monitoring of the drugs evaluated in chicken samples, as all the values were within the acceptable criteria used for food safety. Of 6 samples analyzed, none of them showed contamination of the sulphonamides studied at detectable levels.

Study of the correlation between blood cholinesterases activity, urinary dialkyl phosphates, and the frequency of micronucleated polychromatic erythrocytes in rats exposed to disulfoton

Organophosphates (OPs) are widely used as pesticides, and its urinary metabolites as well as the blood cholinesterases (ChEs) activity have been reported as possible biomarkers for the assessment of this pesticide exposure. Moreover, the OPs can induce mutagenesis, and the bone marrow micronucleus test is an efficient way to assess this chromosomal damage. This paper reports a study carried out to verify the correlation among the disulfoton exposure, blood ChEs activity, urinary diethyl thiophosphate (DETP), and diethyl dithiophosphate (DEDTP), as well as micronucleated polychromatic erythrocytes (MNPCEs) frequency. Four groups of rats (n=12) were exposed to disulfoton at 0, 2.8, 4.7, and 6.6 mg kg-1 body weight. The blood ChEs activity, urinary DETP and DEDTP concentrations, and MNPCEs frequency were determined. It was observed that the plasmatic and erythrocytary ChEs activity decreased from 2.9% to 0.5% and from 35.9 to 3.3%, respectively, when the disulfoton dose was increased from 0 to 6.6 mg kg-1 (correlation of 0.99). Urinary DETP and DEDTP concentrations, as well as the MNPCEs frequency, increased from 0 to 6.58 µg mL-1, from 0 to 0.04 µg mL-1, and from 0 to 1.4%, respectively, when the disulfoton dose was increased from 0 to 6.58 mg kg-1 body weight.

Association and dissociation of autophagy, apoptosis and necrosis by systematic chemical study

To address the question of whether established or experimental anticancer chemotherapeutics can exert their cytotoxic effects by autophagy, we performed a high-content screen on a set of cytotoxic agents. We simultaneously determined parameters of autophagy, apoptosis and necrosis on cells exposed to -1400 compounds. Many agents induced a 'pure' autophagic, apoptotic or necrotic phenotype, whereas less than 100 simultaneously induced autophagy, apoptosis and necrosis. A systematic analysis of the autophagic flux induced by the most potent 80 inducers of GFP-LC3 puncta among the NCI panel agents showed that 59 among them truly induced autophagy. The remaining 21 compounds were potent inducers of apoptosis or necrosis, yet failed to stimulate an autophagic flux, which were characterized as microtubule inhibitors. Knockdown of ATG7 was efficient in preventing GFP-LC3 puncta, yet failed to attenuate cell death by the agents that induce GFP-LC3 puncta. Thus there is not a single compound that would induce cell death by autophagy in our screening, underscoring the idea that cell death is rarely, if ever, executed by autophagy in human cells.

Decrease in the expression of N-methyl-D-aspartate receptors in the nucleus tractus solitarii induces antinociception and increases blood pressure

N-methyl-D-aspartate receptors (NMDAR) have a role in cardiovascular control at the nucleus tractus solitarii (NTS), eliciting increases or decreases in blood pressure (BP), depending on the area injected with the agonists. In spite of the association between cardiovascular control and pain modulation, the effects of manipulating NMDAR in pain responses have never been evaluated. In this study, we decreased the expression of NMDAR in the NTS using gene transfer to target receptor subunits and evaluate long-term effects. Seven days after the injection of lentiviral vectors containing the NR1a subunit cDNA of NMDAR, in antisense orientation, into the intermediate NTS of Wistar rats, BP was measured, and the formalin test of nociception was performed. The antisense vector induced a decrease of NR1 expression in the NTS and elicited BP rises and hypoalgesia. Antisense vectors inhibited formalin-evoked c-Fos expression in the spinal cord, indicating decreased nociceptive activity of spinal neurons. Using a time-course approach, we verified that the onset of both the increases in BP and the hypoalgesia was at 4 days after vector injection into the NTS. The injection of NMDA into the NTS reversed the effects of antisense vectors in pain behavioral responses and spinal neuronal activation and decreased BP and heart rate. The present study shows that the NR1 subunit of the NMDAR at the NTS is critical in the regulation of tonic cardiovascular and nociceptive control and shows an involvement of the nucleus in the modulation of sustained pain.