RESUMEN
Growing evidence for global pollinator decline is causing concern for biodiversity conservation and ecosystem services maintenance. Neonicotinoid pesticides have been identified or suspected as a key factor responsible for this decline. We assessed the global exposure of pollinators to neonicotinoids by analyzing 198 honey samples from across the world. We found at least one of five tested compounds (acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam) in 75% of all samples, 45% of samples contained two or more of these compounds, and 10% contained four or five. Our results confirm the exposure of bees to neonicotinoids in their food throughout the world. The coexistence of neonicotinoids and other pesticides may increase harm to pollinators. However, the concentrations detected are below the maximum residue level authorized for human consumption (average ± standard error for positive samples: 1.8 ± 0.56 nanograms per gram).
Asunto(s)
Abejas/efectos de los fármacos , Abejas/fisiología , Contaminación de Alimentos , Miel/análisis , Insecticidas/análisis , Neonicotinoides/análisis , Animales , Biodiversidad , Guanidinas/análisis , Guanidinas/toxicidad , Insecticidas/toxicidad , Neonicotinoides/toxicidad , Nitrocompuestos/análisis , Nitrocompuestos/toxicidad , Oxazinas/análisis , Oxazinas/toxicidad , Polinización , Tiametoxam , Tiazinas/análisis , Tiazinas/toxicidad , Tiazoles/análisis , Tiazoles/toxicidadRESUMEN
OBJECTIVE: To assess the appointment conditions and characteristics of patients who miss their appointments ('no-shows'); this will aid in the formulation of intervention methods to reduce no-show rates. METHODS: During a one-month period, data on all no-shows at the general internal medicine outpatient clinic of the Geneva University Hospitals were collected. Control patients were matched for appointment time and gender. Patient and appointment characteristics were collated on 13 parameters, and these were compared between no-shows and controls. RESULTS: Two hundred and six of 1296 appointments were no-shows (15.8%). Compared with controls, no-shows were younger, born earlier in the year, more often were not Europeans, more often had a common language with the physician or translator (no communication problems), and more often had a follow-up (not first) appointment. Other parameters were not significant (appointment day of week and time of day, gender, residency status, insurance coverage, family physician, medical consequences, covert addiction). CONCLUSIONS: The no-show rate was within the range for comparable settings. Several parameters associated with no-shows reflected specifics of a hospital-based adult outpatient clinic that mainly serves middle-to-low socio-economic classes and is a referral clinic for refugees in a middle-sized European city with a high percentage of foreigners with different backgrounds and languages. Planned interventions should consider local factors.
Asunto(s)
Citas y Horarios , Hospitales Universitarios , Servicio Ambulatorio en Hospital , Cooperación del Paciente , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Cooperación del Paciente/estadística & datos numéricos , SuizaRESUMEN
As anyone else, diabetic patients are confronted to professional or private travels. This article is meant to gather some practical recommendations to allow patients to travel safely. All travels must be thoroughly prepared and diabetes must stabilised at best before departure. To avoid severe hypoglycaemias and ketosis are the medical objectives. It is therefore essential that patients take with them their injection material and a sufficient carbohydrate back up. The prevention of diarrheas and vomiting, as well as the adaptation of treatment to jet-lag and all kind of physical activity are necessary to have a nice travel. Some specific aspects of travelling by car, boat or plane are discussed.
Asunto(s)
Complicaciones de la Diabetes/prevención & control , Diabetes Mellitus/terapia , Viaje , Documentación , HumanosRESUMEN
A series of antagonists of gonadotropin-releasing hormone (GnRH) of the general formula Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph/4Amf(P)-D4Aph/D4Amf(Q)-Leu-ILys-Pro-DAla-NH2 was synthesized, characterized, and screened for duration of inhibition of luteinizing hormone release in a castrated male rat assay. Selected analogues were tested in a reporter gene assay (IC50 and pA2) and an in vitro histamine release assay. P and Q contain urea/carbamoyl functionalities designed to increase potential intra- and intermolecular hydrogen bonding opportunities for structural stabilization and peptide/receptor interactions, respectively. These substitutions resulted in analogues with increased hydrophilicity and a lesser propensity to form gels in aqueous solution than azaline B [Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(Atz)-D4Aph(Atz)-Leu-ILys-Pro-DAla-NH2 with Atz = 3'-amino-1H-1',2',4'-triazol-5'-yl, 5], and in some cases they resulted in a significant increase in duration of action after subcutaneous (s.c.) administration. Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(L-hydroorotyl)-D4Aph(carbamoyl)-Leu-ILys-Pro-DAla-NH2 (acetate salt is FE200486) (31) and eight other congeners (20, 35, 37, 39, 41, 45-47) were identified that exhibited significantly longer duration of action than acyline [Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(Ac)-D4Aph(Ac)-Leu-ILys-Pro-DAla-NH2] (6) when administered subcutaneously in castrated male rats at a dose of 50 microg in 100 microL of phosphate buffer. No correlation was found between retention times on a C18 reverse phase column using a triethylammonium phosphate buffer at pH 7.0 (a measure of hydrophilicity) or affinity in an in vitro human GnRH report gene assay (pA2) and duration of action. FE200486 was selected for preclinical studies, and some of its properties were compared to those of other clinical candidates. In the intact rat, ganirelix, abarelix, azaline B, and FE200486 inhibited plasma testosterone for 1, 1, 14, and 57 days, respectively, at 2 mg/kg s.c. in 5% mannitol (injection volume = 20 microL). Based on the information that 31, 33, 35 and 37 were significantly shorter acting than acyline or azaline B after intravenous administration (100 microg/rat), we surmised that the very long duration of action of the related FE200486 (for example) was likely due to unique physicochemical properties such as solubility in aqueous milieu, comparatively low propensity to form gels, and ability to diffuse at high concentrations in a manner similar to that described for slow release formulations of peptides. Indeed, in rats injected s.c. with FE200486 (2 mg/kg), plasmatic concentrations of FE200486 remained above 5 ng/mL until day 41, and the time after which they dropped below 3 ng/mL and plasma LH levels started rising until full recovery was reached at day 84 with levels of FE200486 hovering around 1 ng/mL. Additionally, FE200486 was less potent at releasing histamine from isolated rat mast cells than any of the GnRH antagonists presently described in preclinical reports.
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Hormona Liberadora de Gonadotropina/antagonistas & inhibidores , Oligopéptidos/síntesis química , Fenilalanina/análogos & derivados , Fenilalanina/síntesis química , Urea/análogos & derivados , Urea/síntesis química , Animales , Línea Celular , Evaluación Preclínica de Medicamentos , Geles , Genes Reporteros , Liberación de Histamina/efectos de los fármacos , Humanos , Hormona Luteinizante/sangre , Masculino , Mastocitos/metabolismo , Oligopéptidos/química , Oligopéptidos/farmacología , Orquiectomía , Fenilalanina/química , Fenilalanina/farmacología , Ratas , Ratas Sprague-Dawley , Solubilidad , Relación Estructura-Actividad , Testosterona/sangre , Urea/química , Urea/farmacologíaRESUMEN
The pulsatile luteinizing hormone (LH) and testosterone secretions were studied during serial blood collections performed at 7-min time intervals in the male rat. In fed rats, a discontinuous pattern of LH secretion was observed. Periods without secretion alternated with active secretory episodes consisting in trains of three to four LH peaks that triggered testosterone secretion usually 1-2 h later. The magnitude of the testosterone response was not correlated with the amplitude of the LH peaks. Isolated, single peaks of LH did not evoke clear testosterone responses. Forty-eight hours after initiation of fasting, testosterone secretion was markedly decreased, but integrated LH secretion was only partly reduced. Chronic infusion of neuropeptide Y (NPY; 18 microgram/day, icv) reduced testosterone secretion to very low levels and abolished pulsatile LH secretion or testosterone response to isolated LH peaks. In conclusion, the stimulation of testosterone secretion by LH necessitates several LH peaks organized in a proper sequence, and the testosterone response is not immediate. Low testosterone secretion in fasting rats appears to result from disappearance of coordinated, multiple LH peaks of sufficient size. Inhibition of the gonadotropic axis achieved by central NPY administration is due to either absence of LH peak "clusters" or occurrence of nonfunctional single LH peaks.
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Ventrículos Cerebrales/fisiología , Ayuno/fisiología , Hormona Luteinizante/metabolismo , Neuropéptido Y/farmacología , Vesículas Seminales/fisiología , Testículo/fisiología , Testosterona/metabolismo , Ciclos de Actividad , Animales , Ventrículos Cerebrales/efectos de los fármacos , Homeostasis , Infusiones Parenterales , Hormona Luteinizante/sangre , Masculino , Neuropéptido Y/administración & dosificación , Tamaño de los Órganos/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Vesículas Seminales/efectos de los fármacos , Testículo/efectos de los fármacos , Testosterona/sangreRESUMEN
We have previously described the preparation, purification and partial characterization of recombinant (rec) forms of rat luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In the present study, the special functional features of these hormones were studied further, in vitro and in vivo, and compared with human recLH and recFSH, as well as with human urinary choriongonadotropin (hCG) and rat pituitary LH (NIDDK-RP3). In radioreceptor assay, the affinity of hCG binding to rat testis membranes was 5-fold higher than that of human recLH and 100-fold higher than that of rat recLH. In in vitro bioassay, using dispersed adult mouse interstitial cells or a mouse Leydig tumor cell line (BLT-1), hCG and human recLH were 10- to 20-fold more potent than rat recLH. Correspondingly, rat pituitary LH was about 10-fold less potent than rat recLH, and evoked a maximum testosterone response that was about half of that elicited by the other LH/CG preparations. Rat recFSH was about 10-fold less potent than human recFSH in stimulating cAMP production of a mouse Sertoli cell line (MSC-1) expressing the recombinant rat FSH receptor. The circulating half-times (T1/2) of rat and human rec hormones were assessed after i.v. injections into adult male rats rendered gonadotropin-deficient by treatment with a gonadotropin-releasing hormone antagonist. A novel immunometric assay was used for the rat FSH measurements. In the one-component model the T1/2 values of rat and human recLH were 18.2 +/- 1.9 min (n = 7) and 44.6 +/- 3.1 min (n = 7) respectively and those of rat and human recFSH were 88.4 +/- 10.7 min (n = 6) and 55.0 +/- 4.2 min (n = 6) respectively; the two-component models revealed similar differences between the rec hormone preparations. Collectively, rat recLH was eliminated significantly faster from the circulation than human recLH (P < 0.0001). In contrast, the elimination of rat recFSH was significantly slower than that of human recFSH (P = 0.02). In conclusion, rat recFSH and rat recLH display lower biopotencies per unit mass than the respective human hormones in vitro, and also in vivo for LH. This is paralleled by shorter T1/2 of rat recLH than the respective human hormone in the circulation, whereas human recFSH has a shorter T1/2 than human FSH. The special functional features of the rat rec gonadotropins emphasize the use of these preparations on studies of gonadotropin function in the rat, an important animal model for reproductive physiology.
Asunto(s)
Hormona Folículo Estimulante/farmacología , Hormona Luteinizante/farmacología , Animales , Bioensayo , Gonadotropina Coriónica/farmacología , AMP Cíclico/biosíntesis , Hormona Folículo Estimulante/farmacocinética , Semivida , Células Intersticiales del Testículo/efectos de los fármacos , Células Intersticiales del Testículo/metabolismo , Hormona Luteinizante/farmacocinética , Masculino , Ratones , Ratones Endogámicos , Ensayo de Unión Radioligante , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/farmacología , Células de Sertoli/efectos de los fármacos , Células de Sertoli/metabolismo , Especificidad de la Especie , Testosterona/biosíntesisRESUMEN
The ability of hCG and LH to induce testosterone (T) secretion by Leydig cells is well documented. However, the influence of the pulsatile nature of LH secretion, with varying frequency and amplitude, on T production in vivo is less clear. In our earlier studies on the relationship between pulsatile LH release and T secretion in adult male rats, no simple causality was observed. The recent availability of rat recombinant (rec) LH prompted us to study the effects of one and of three i.v. pulses of different doses of rat recLH on T secretion in adult male rats rendered hypogonadotropic by treatment with the GnRH antagonist cetrorelix. One or three supraphysiological pulses of 1.0 microg of rat recLH produced similar maximal T responses. In contrast, high physiological LH pulses (0.1 microg) produced discrete T-response peaks, whereas multiple low pulses of LH (0.03 microg) were needed before a T response was achieved. The T stimulation was greatly diminished after an LH pulse of 0.1 microg if rats had been treated on the previous day with pulses of 0.03 vs. 0.1 microg rat recLH, apparently because of prolonged LH deprivation and lack of Leydig cell priming due to the GnRH antagonist treatment. The novel preparation of rat recLH provides a physiologically relevant tool for studying the complex relationship between pulsatile LH release and T secretion in male rats.
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Hormona Luteinizante/farmacología , Testículo/metabolismo , Testosterona/metabolismo , Animales , Relación Dosis-Respuesta a Droga , Inyecciones Intravenosas , Células Intersticiales del Testículo/efectos de los fármacos , Células Intersticiales del Testículo/metabolismo , Masculino , Tamaño de los Órganos/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/farmacología , Testículo/efectos de los fármacos , Factores de TiempoRESUMEN
Neuropeptide Y (NPY) is known to be involved in the central regulation of appetite, sexual behavior, and reproductive function. Whereas central administration of NPY strongly stimulates feeding in satiated animals, diet restriction or other unfavorable metabolic situations, such as diabetes, produce enhanced NPY gene expression and NPY release in the hypothalamus. Numerous studies have indicated that acute central administration of NPY results in various actions on LH secretion in the rat, either stimulatory or inhibitory. We recently demonstrated that chronic infusion of NPY into the lateral ventricle of adult intact female rats profoundly inhibited both the gonadotropic and somatotropic axes, with disruption of estrous cyclicity. Furthermore, we showed that central chronic infusion of NPY delayed sexual maturation in female rats. To analyze the effects of the same type of chronic NPY treatment on the pituitary-testicular axis, 45-day-old Sprague-Dawley male rats were implanted with stainless steel cannulas in the right lateral ventricle. Ten days later, Alzet osmotic minipumps were filled with different NPY solutions, adjusted to deliver 6, 18, or 36 micrograms/day, connected to the intracerebroventricular (icv) cannula, and sc implanted dorsally. The effects of these treatments were evaluated over 7 days. In one case, rats were castrated 5 days after initiation of NPY treatment, and the effect of castration was evaluated 2 days later. Chronic icv infusion of NPY produced the expected dose-related increases in food intake from 33.0 +/- 0.9 (basal) to 53.4 +/- 3.3 g/day (18 micrograms NPY/day) and body weight gain (5.7 +/- 0.7 to 10.5 +/- 1.2 d/day). As in female rats, this orexigenic action of NPY resulted in a significant dose-related decrease in pituitary weight, from 12.4 +/- 0.7 to 9.9 +/- 0.4 mg. The 7-day NPY infusion produced highly significant decreases in seminal vesicle weight (853 +/- 77 to 230 +/- 31 mg) and testis weight (3.82 +/- 0.09 to 3.18 +/- 0.15 g; P = 0.003). Plasma levels of testosterone (231 +/- 71 to 48 +/- 13 ng/dl), LH (20.7 +/- 3.7 to 9.1 +/- 1.2 ng/ml), and FSH (282 +/- 17 to 190 +/- 18 ng/ml) were markedly decreased at the 18 micrograms/day dosage, as also demonstrated for the 36 micrograms/day dosage. None of these effects was observed if vehicle was infused into the lateral ventricle instead of the NPY solution. When bilateral orchidectomy was performed 5 days after initiation of the NPY infusion (18 micrograms/day), the immediate LH and FSH rises usually seen after castration were seriously blunted.(ABSTRACT TRUNCATED AT 400 WORDS)