The molecular mechanism of Nystatin action is dependent on the membrane biophysical properties and lipid composition.

Nystatin (Nys) is a pore forming broad-spectrum and efficient antifungal drug with significant toxicity in mammalian organisms. In order to develop a non-toxic and more effective Nys formulation, its molecular mechanism of action at the cell membrane needs to be better understood. It is widely accepted that Nys activity and toxicity depend on the presence and type of membrane sterols. Taking advantage of multiple biophysical methodologies, we now show that the formation and stabilization of Nys aqueous pores, which are associated with Nys cytotoxicity, occur in the absence of membrane sterols. Our results suggest that the Nys mechanism of action is driven by the presence of highly ordered membrane domains capable of stabilizing the Nys oligomers. Moreover, Nys pore formation is accompanied by strong Nys-induced membrane reorganization that depends on membrane lipid composition and seems to underlie the Nys cytotoxic effect. Accordingly, in membranes enriched in a gel-phase forming phospholipid, Nys incorporates within the phospholipid-enriched gel domains, where it forms pores able to expand the gel domains. In contrast, in membranes enriched in gel domain forming sphingolipids, Nys-induced pore formation occurs through the destabilization of the gel phase. These results show that the Nys mechanism of action is complex and not only dependent on membrane sterols, and provide further insight into the molecular details governing Nys activity and toxicity.

Neuroprotective effects of guanosine administration on behavioral, brain activity, neurochemical and redox parameters in a rat model of chronic hepatic encephalopathy.

It is well known that glutamatergic excitotoxicity and oxidative stress are implicated in the pathogenesis of hepatic encephalopathy (HE). The nucleoside guanosine exerts neuroprotective effects through the antagonism against glutamate neurotoxicity and antioxidant properties. In this study, we evaluated the neuroprotective effect of guanosine in an animal model of chronic HE. Rats underwent bile duct ligation (BDL) and 2 weeks later they were treated with i.p. injection of guanosine 7.5 mg/kg once a day for 1-week. We evaluated the effects of guanosine in HE studying several aspects: a) animal behavior using open field and Y-maze tasks; b) brain rhythm changes in electroencephalogram (EEG) recordings; c) purines and glutamate levels in the cerebral spinal fluid (CSF); and d) oxidative stress parameters in the brain. BDL rats presented increased levels of glutamate, purines and metabolites in the CSF, as well as increased oxidative damage. Guanosine was able not only to prevent these effects but also to attenuate the behavioral and EEG impairment induced by BDL. Our study shows the neuroprotective effects of systemic administration of guanosine in a rat model of HE and highlights the involvement of purinergic system in the physiopathology of this disease.

Occupational exposure to pesticides deregulates systemic cortisol levels in women with breast cancer and correlates with poor prognosis features.

Pesticides have been pointed out as hormone disruptors and may significantly affect the prognosis of hormone-dependent diseases such as breast cancer (BC). Here, we investigated the impact of occupational pesticide exposure on systemic cortisol levels in female rural workers diagnosed with BC. Occupational exposure was assessed by interviews with a standardized questionnaire. Plasma samples (112 from pesticide-exposed women and 77 from unexposed women) were collected in the afternoon, outside the physiological cortisol peak, and analyzed by a chemiluminescent paramagnetic immunoassay for the quantitative determination of cortisol levels in serum and plasma. The results from both groups were categorized according to patients' clinicopathological and exposure data. BC pesticide-exposed women presented higher levels of cortisol than the unexposed. Higher cortisol levels were also detected in the exposed group with more aggressive disease (triple-negative BC), with tumors over 2 cm, with lymph node metastases, and with high risk of disease recurrence and death. These findings demonstrated that there is an association between pesticide exposure and BC that affected cortisol levels and correlated to poor disease prognosis.

Metal and metalloid content, bioavailability and sorption processes in glitter and raw glitter materials and associations with human and ecological risk concerns.

BACKGROUND: Microplastics comprise a significant group of emerging environmental contaminants with the capacity to adsorb several contaminants. These, in turn, undergo bioaccumulation and biomagnification processes throughout aquatic trophic chains. METHODS: Glitter, a microplastic powder composed of a combination of polymers, and raw glitter materials were investigated herein concerning metal and metalloid content, bioavailability, and sorption processes by inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: Metal and metalloid concentrations were higher in glitter than in raw glitter materials, but all were below the limits established by the Brazilian National Health Surveillance Agency. Elements present in glitter originate mainly from pigments and, thus, depend on glitter color. The bioavailability of the determined elements concerning human skin was assessed. Low desorbed concentrations in solution indicate that glitter does not represent a health risk through dermal contact concerning metal and metalloid contamination. However, several elements were shown to undergo significant desorption and adsorption processes. CONCLUSION: The findings reported herein indicate seemingly low human health risks from dermal glitter contact but reinforce glitter risks as aquatic environment metal and metalloid transport vectors.

Mammalian sphingoid bases: Biophysical, physiological and pathological properties.

Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules, and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.

Mammalian sphingoid bases: Biophysical, physiological and pathological properties.

Sphingoid bases encompass a group of long chain amino alcohols which form the essential structure of sphingolipids. Over the last years, these amphiphilic molecules were moving more and more into the focus of biomedical research due to their role as bioactive molecules. In fact, free sphingoid bases interact with specific receptors and target molecules and have been associated with numerous biological and physiological processes. In addition, they can modulate the biophysical properties of biological membranes. Several human diseases are related to pathological changes in the structure and metabolism of sphingoid bases. Yet, the mechanisms underlying their biological and pathophysiological actions remain elusive. Within this review, we aimed to summarize the current knowledge on the biochemical and biophysical properties of the most common sphingoid bases and to discuss their importance in health and disease.

Behavioral, Neurochemical and Brain Oscillation Abnormalities in an Experimental Model of Acute Liver Failure.

Hepatic encephalopathy (HE) represents a brain dysfunction caused by both acute and chronic liver failures, and its severity deeply affects the prognosis of patients with impaired liver function. In its pathophysiology, ammonia levels and glutamatergic system hyperactivity seem to play a pivotal role in the disruption of brain homeostasis. Here, we investigate important outcomes involved in behavioral performance, electroencephalographic patterns, and neurochemical parameters to better characterize the well-accepted animal model of acute liver failure (ALF) induced by subtotal hepatectomy (92% removal of tissue) that produces ALF. This study was divided into three cohorts: (1) rats clinically monitored after hepatectomy every 6 h for 96 h or until death; (2) rats tested in an open-field task (OFT) before and after surgery and had blood, cerebrospinal fluid, and brain tissue collected after the last OFT; and (3) rats that had continuous EEGs recorded before and after surgery for 3 days. The hepatectomized rats presented significant motor behavioral changes accompanied by important abnormalities in classical blood laboratory parameters of ALF, and EEG features suggestive of HE and deep disturbances in the brain glutamatergic system. Using an animal model of ALF induced via subtotal hepatectomy, this work provides a comprehensive and reliable experimental model that increases the opportunity for studying the effects of new treatment strategies to be explored in an unprecedented way. It also presents insights into the pathophysiology of HE in a reproducible model of ALF, which correlates important neurochemical and EEG aspects of the syndrome.

Occupational exposure to pesticides deregulates systemic cortisol levels in women with breast cancer and correlates with poor prognosis features

Pesticides have been pointed out as hormone disruptors and may significantly affect the prognosis of hormone-dependent diseases such as breast cancer (BC). Here, we investigated the impact of occupational pesticide exposure on systemic cortisol levels in female rural workers diagnosed with BC. Occupational exposure was assessed by interviews with a standardized questionnaire. Plasma samples (112 from pesticide-exposed women and 77 from unexposed women) were collected in the afternoon, outside the physiological cortisol peak, and analyzed by a chemiluminescent paramagnetic immunoassay for the quantitative determination of cortisol levels in serum and plasma. The results from both groups were categorized according to patients' clinicopathological and exposure data. BC pesticide-exposed women presented higher levels of cortisol than the unexposed. Higher cortisol levels were also detected in the exposed group with more aggressive disease (triple-negative BC), with tumors over 2 cm, with lymph node metastases, and with high risk of disease recurrence and death. These findings demonstrated that there is an association between pesticide exposure and BC that affected cortisol levels and correlated to poor disease prognosis.

Attitude of medical professionals regarding controversial issues in kidney donation/transplantation.

There is a dire need to evaluate new strategies to bridge the wide kidney demand-supply gap. The current study examined the attitude of medical professionals regarding controversial issues pertaining to transplantation. A questionnaire, presenting controversial issues related to kidney transplantation, in an agree-disagree format with supporting reasons, was employed. The research was exploratory. Data were analyzed quantitatively and qualitatively. The sample comprised 140 doctors from Mumbai (mean = 38.1 years, standard deviation = 17.95; Males = 44.3%, Females = 55.7%). Whereas 47.1% of the participants felt that live donors should be given incentives for kidney donation, others (52.9%) disagreed, fearing commercialization and illegal activities. The eligibility of patients with HIV/hepatitis for a transplant was denied by 52.9% because of poor outcomes, with the others (47.1%) maintaining that these individuals too had a right to live. A substantial majority (90.7%) of the participants maintained that organ donors should be given priority in the event of a future need for an organ because their previous humane act should be rewarded (47.1%). Most of the participants (91.4%) felt that individuals from the higher socioeconomic strata should not receive preference for kidney transplantation. A majority (77.1%) of them were also against kidney selling getting legalized. Compulsory possession of a donor card elicited mixed responses, with some accepting (56.4%), but others rejecting (43.6%) this idea as donation was perceived to be a voluntary act (33.6%). While compulsory kidney donation found favor with 44.3%, it found disfavor with others (55.7%). This study will benefit transplant healthcare personnel to formulate new policies in relation to kidney donation/transplantation.

Copper(I) complexes with phosphine derived from sparfloxacin. Part II: a first insight into the cytotoxic action mode.

In this paper we present a first insight into the cytotoxic action mode of copper(I) iodide or copper(I) thiocyanate complexes with a phosphine derivative of sparfloxacin (a 3rd generation fluoroquinolone antibiotic agent) and 2,9-dimethyl-1,10-phenanthroline or 2,2'-biquinoline as auxiliary ligands. The in vitro cytotoxic activity of the new complexes was tested against two cancer cell lines (CT26--mouse colon carcinoma and A549--human lung adenocarcinoma). An ICP-MS study revealed a marked time-dependent intracellular copper accumulation of the tested compounds. In addition, confocal microscopy imaging showed accumulation of the complexes inside whole cells and their emission of blue light. The complexes generate reactive oxygen species in the cancer cells, which was examined by using two different fluorescent probes. Moreover, (I) DNA intercalation studied by luminescence spectroscopy, circular dichroism and molecular docking, and (II) plasmid DNA damage also demonstrate their significant cytotoxicity. All these observed biological effects contribute to the induction of apoptosis, observed at a great predominance.

Phospholipid/cholesterol/decanethiol mixtures for direct assembly of immunosensing interfaces.

In this work, a simple yet robust method to prepare lipid-based biosensing interfaces on gold using common lipids (a phospholipid and cholesterol) and an alkanethiol is reported. The lipids were carefully chosen to tailor the biophysical properties of the bilayer. The simplicity of the method relies on the incorporation of a small percentage of decanethiol in the lipid vesicles for a direct formation of a thiol-linked supported lipid bilayer, which is advantageous in several respects. It prevents the use of specially synthesized thiolipids and preserves the natural fluidity and dynamics of the lipids. As a consequence the whole arrangement is extremely stable regarding ionic strength changes and solution flow during surface plasmon resonance experiments. Moreover, we show that this interface is very effective on suppressing the nonspecific adsorption of proteins on the surface, and enables the covalent attachment of the recognition antibody. The subsequent detection of specific interaction toward antigen was monitored in real-time by SPR and confirmed by ellipsometric measurements. This lipid-based biosensing platform is versatile and can be adapted to the biorecognition reaction of interest.

Analysis of acylcarnitine profiles in umbilical cord blood and during the early neonatal period by electrospray ionization tandem mass spectrometry.

Acylcarnitine profiling by electrospray ionization tandem mass spectrometry (ESI-MS/MS) is a potent tool for the diagnosis and screening of fatty acid oxidation and organic acid disorders. Few studies have analyzed free carnitine and acylcarnitines in dried blood spots (DBS) of umbilical cord blood (CB) and the postnatal changes in the concentrations of these analytes. We have investigated these metabolites in healthy exclusively breastfed neonates and examined possible effects of birth weight and gestational age. DBS of CB were collected from 162 adequate for gestational age neonates. Paired DBS of heel-prick blood were collected 4-8 days after birth from 106 of these neonates, the majority exclusively breastfed. Methanol extracts of DBS with deuterium-labeled internal standards were derivatized before analysis by ESI-MS/MS. Most of the analytes were measured using a full-scan method. The levels of the major long-chain acylcarnitines, palmitoylcarnitine, stearoylcarnitine, and oleoylcarnitine, increased by 27, 12, and 109%, respectively, in the first week of life. Free carnitine and acetylcarnitine had a modest increase: 8 and 11%, respectively. Propionylcarnitine presented a different behavior, decreasing 9% during the period. The correlations between birth weight or gestational age and the concentrations of the analytes in DBS were weak (r ≤ 0.20) or nonsignificant. Adaptation to breast milk as the sole source of nutrients can explain the increase of these metabolites along the early neonatal period. Acylcarnitine profiling in CB should have a role in the early detection of metabolic disorders in high-risk neonates.

Diferentes fontes de ferro na prevenção da anemia ferropriva e no desempenho de leitões lactentes / Different sources of iron for the prevention of iron deficiency anemia and performance of suckling piglets

Com o objetivo de avaliar o uso de diferentes fontes de ferro na prevenção da anemia ferropriva e no desempenho em leitões lactentes, dividiram-se 202 leitões em cinco tratamentos: FD - aplicação intramuscular de 200mg de ferro dextrano no terceiro dia de idade; T24 - terra à vontade fornecida aos leitões a cada 24 horas do terceiro ao 19º dia; T48 - terra à vontade fornecida aos leitões a cada 24 horas do terceiro ao 10º dia e do 11º ao 19º dia, com intervalo de 48 horas; T72 - terra à vontade fornecida aos leitões a cada 24 horas do terceiro ao 10º dia e do 11º ao 19º dia, com intervalo de 72 horas; SA - suplemento alimentar ultraprecoce rico em ferro quelatado em pó (SAUP) fornecido do terceiro ao 11º dia, com intervalo de 48 horas. O ferro dextrano aplicado no terceiro dia de vida e a suplementação com terra e SAUP foram eficientes para garantir o desempenho de leitões no período de aleitamento e não influenciaram no consumo de ração nem na taxa de viabilidade. As diferentes fontes de ferro estudadas não influenciaram o leucograma e foram eficientes na prevenção da anemia ferropriva e no desempenho dos leitões lactentes. Com relação às concentrações de hemoglobina e hematócrito, os animais suplementados com ferro dextrano apresentaram valores superiores quando comparados aos que recebem terra e SAUP.(AU)

In order to evaluate the use of different sources of iron to prevent iron deficiency anemia and to appraise the performance of suckling piglets, we sorted 202 piglets in five treatments. ID - intramuscular injection of 200mg of iron dextran on the third day of age; T24 - free daily access to land provided to piglets every 24 hours from the third to the nineteenth day; T48 - free daily access to land provided to piglets every 24 hours from the third to the tenth day and from day 11 to day 19 with an interval of 48 hours; T72 - free daily access to land provided to piglets every 24 hours from the third to the tenth day and from day 11 to day 19 with an interval of 72 hours; FS - Food supplement rich in iron-chelating powder (SAUP) available from the third to the eleventh day with an interval of 48 hours. The iron dextran applied on the third day of life as well as the supplementation with land and SAUP were effective to ensure the performance of piglets during the lactation period and did not affect feed intake or the viability rate. The different sources of iron studied did not influence the WBC (White Blood Cell) and succeded in preventing iron deficiency anemia and performance of suckling piglets. Regarding the concentrations of hemoglobin and hematocrit, the animals supplemented with iron dextran showed higher values when compared to those who receive land and SAUP.(AU)

Anne Frank's headache.

There are a significant number of famous people who suffered from frequent headaches during their lifetime while also exerting an influence of some kind on politics or the course of history. One such person was Anneliese Marie Frank, the German-born Jewish teenager better known as Anne Frank, who was forced into hiding during World War II. When she turned 13, she received a diary as a present, named it 'Kitty' and started to record her experiences and feelings. She kept the diary during her period in hiding, describing her daily life, including the feeling of isolation, her fear of being discovered, her admiration for her father and her opinion about women's role in society, as well as the discovery of her own sexuality. She sometimes reported a headache that disturbed her tremendously. The 'bad' to 'terrifying' and 'pounding' headache attacks, which were accompanied by vomiting and during which she felt like screaming to be left alone, matched the International Headache Society criteria for probable migraine, whereas the 'more frequent headaches' described by Anne's father are more likely to have been tension-type headaches than headaches secondary to ocular or other disorders.

Analysis of acylcarnitine profiles in umbilical cord blood and during the early neonatal period by electrospray ionization tandem mass spectrometry

Acylcarnitine profiling by electrospray ionization tandem mass spectrometry (ESI-MS/MS) is a potent tool for the diagnosis and screening of fatty acid oxidation and organic acid disorders. Few studies have analyzed free carnitine and acylcarnitines in dried blood spots (DBS) of umbilical cord blood (CB) and the postnatal changes in the concentrations of these analytes. We have investigated these metabolites in healthy exclusively breastfed neonates and examined possible effects of birth weight and gestational age. DBS of CB were collected from 162 adequate for gestational age neonates. Paired DBS of heel-prick blood were collected 4-8 days after birth from 106 of these neonates, the majority exclusively breastfed. Methanol extracts of DBS with deuterium-labeled internal standards were derivatized before analysis by ESI-MS/MS. Most of the analytes were measured using a full-scan method. The levels of the major long-chain acylcarnitines, palmitoylcarnitine, stearoylcarnitine, and oleoylcarnitine, increased by 27, 12, and 109%, respectively, in the first week of life. Free carnitine and acetylcarnitine had a modest increase: 8 and 11%, respectively. Propionylcarnitine presented a different behavior, decreasing 9% during the period. The correlations between birth weight or gestational age and the concentrations of the analytes in DBS were weak (r £ 0.20) or nonsignificant. Adaptation to breast milk as the sole source of nutrients can explain the increase of these metabolites along the early neonatal period. Acylcarnitine profiling in CB should have a role in the early detection of metabolic disorders in high-risk neonates.