RESUMEN
BACKGROUND: Children with Down syndrome (DS) demonstrate poorer performance in locomotor and ball skills than children with typical development. During motor assessment, keeping children's attention and motivation is challenging, especially for children with DS, which may affect the test outcomes. This study aimed first to examine the impact of examiner and App-animation demonstrations during the assessment on the performance of fundamental motor skills, focus of attention and intrinsic motivation for children with DS and neurotypical development (NTD). The secondary aim was to examine the differences in those outcomes between children with DS and neurotypical development. METHODS: A sample of 24 children (10 with DS and 14 with NTD) aged between 3 and 10 years were subjected to two motor performance assessment protocols: a traditional protocol using the Gross Motor Development Test-3 (TGMD-3) and a protocol using animations from an application as support for TGMD-3 (AppP). The focus of attention was obtained from video recordings during protocol instruction (number of eye shifts, eye shift time, instruction focus time, number of instructions required and total instruction time). Intrinsic motivation was assessed by the Intrinsic Motivation Inventory (IMI) at the end of each protocol. RESULTS: The results showed no significant differences between the protocols for locomotor skills, ball skills and gross motor index. However, children with NTD outperformed those with DS in these skills. When analysing the focus of attention, children with DS showed greater ocular deviations and longer instruction time requested in the traditional protocol compared with AppP, even when compared with NDT children. When comparing protocols in both groups, AppP demonstrated fewer ocular deviations and shorter ocular deviation times. Regarding intrinsic motivation, children with DS in the traditional protocol had lower motivation scores than those with NTD. Regarding the purchase of protocols, in both groups, the AppP presented higher scores for interest/pleasure, perceived competence and general motivation, with lower pressure/tension. CONCLUSION: The animated application (AppP) proved effective as a visual support during the TGMD-3 assessment, particularly benefiting children with DS by enhancing motivation and attention.
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Atención , Síndrome de Down , Motivación , Destreza Motora , Humanos , Síndrome de Down/fisiopatología , Motivación/fisiología , Niño , Masculino , Femenino , Atención/fisiología , Destreza Motora/fisiología , Preescolar , Desarrollo Infantil/fisiologíaRESUMEN
The usefulness of a test is determined by the clinical interpretation of its sensitivity and specificity. The pitfalls of a test with a surgical endpoint are described in this article, taking the diagnosis of deep endometriosis by imaging as an example, without discussing the management of deep endometriosis. Laparoscopy is not a 100% accurate "gold standard". Since it is not performed in women without symptoms, results are valid only for the group of women as specified in the indication for surgery. The confidence limits of accuracy estimations widen when accuracy is lower and when observations are less. Since positive and negative predictive values are inaccurate when prevalence of the disease is low, prevalence figures in the group of women investigated should be available. The accuracy of imaging should be stratified by clinically important aspects such as localisation and size of the lesion. The use of other variables as soft markers during ultrasonographic examination should be specified. It should be clear whether the accuracy of the test reflects symptoms and clinical examination and imaging combined, or whether the accuracy of the added value of imaging which requires Bayesian analysis. When imaging is used as an indication for surgery, circular reasoning should be avoided and the number of symptomatic women not undergoing surgery because of negative imaging should be reported. In conclusion, imaging reports should permit the clinician to judge the validity of the accuracy estimations of a diagnostic test, especially when used as an indication for surgery and when surgery is the gold standard to diagnose a disease.
RESUMEN
The COVID-19 epidemic is believed to have started in late January 2020 in France. Here we report a case of a patient hospitalised in December 2019 in an intensive care unit in a hospital in the north of Paris for haemoptysis with no aetiological diagnosis. RT-PCR was performed retrospectively on the stored respiratory sample and confirmed the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Based on this result, it appears that the COVID-19 epidemic started much earlier in France.
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Betacoronavirus/aislamiento & purificación , Infecciones por Coronavirus/epidemiología , Neumonía Viral/epidemiología , Adulto , Anciano , COVID-19 , Femenino , Francia/epidemiología , Humanos , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Pandemias , Estudios Retrospectivos , SARS-CoV-2RESUMEN
BACKGROUND: Physical inactivity is a key contributor to the global burden of disease and disproportionately impacts the wellbeing of people experiencing mental illness. Increases in physical activity are associated with improvements in symptoms of mental illness and reduction in cardiometabolic risk. Reliable and valid clinical tools that assess physical activity would improve evaluation of intervention studies that aim to increase physical activity and reduce sedentary behaviour in people living with mental illness. METHODS: The five-item Simple Physical Activity Questionnaire (SIMPAQ) was developed by a multidisciplinary, international working group as a clinical tool to assess physical activity and sedentary behaviour in people living with mental illness. Patients with a DSM or ICD mental illness diagnoses were recruited and completed the SIMPAQ on two occasions, one week apart. Participants wore an Actigraph accelerometer and completed brief cognitive and clinical assessments. RESULTS: Evidence of SIMPAQ validity was assessed against accelerometer-derived measures of physical activity. Data were obtained from 1010 participants. The SIMPAQ had good test-retest reliability. Correlations for moderate-vigorous physical activity was comparable to studies conducted in general population samples. Evidence of validity for the sedentary behaviour item was poor. An alternative method to calculate sedentary behaviour had stronger evidence of validity. This alternative method is recommended for use in future studies employing the SIMPAQ. CONCLUSIONS: The SIMPAQ is a brief measure of physical activity and sedentary behaviour that can be reliably and validly administered by health professionals.
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Ejercicio Físico , Trastornos Mentales , Conducta Sedentaria , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Encuestas y Cuestionarios , Adulto JovenRESUMEN
High performance athletes are constantly facing different situations involving stress. Salivary cortisol has been used as a physiological measure to verify high performance athlete and mental health, in spite of research that has shown that comparisons between cortisol levels in athletes and nonathletes are inconclusive. The purpose of this study was to review articles that investigated salivary cortisol levels at rest in high performance athletes in comparison to physically active or sedentary nonathlete individuals. PubMed, ISI Web of Knowledge, SciELO, LILACS, and Scopus databases were searched for studies on salivary cortisol in athletes and the size effect was calculated. Although 3 articles reported higher salivary cortisol levels in female athletes compared to a control group, the results showed homogeneity among baseline groups or groups in resting conditions, suggesting a lack of discriminative capacity. These results should be interpreted with caution, due to the presence of substantial methodological bias.
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Atletas , Hidrocortisona/metabolismo , Saliva/metabolismo , Adolescente , Adulto , Femenino , Humanos , Masculino , Conducta Sedentaria , Deportes , Adulto JovenRESUMEN
The effect of physical exercise on the treatment of depressive elderly adults has not been investigated thus far in terms of changes in cortical hemispheric activity. The objective of the present study was to identify changes in depressive symptoms, quality of life, and cortical asymmetry produced by aerobic activity. Elderly subjects with a diagnosis of major depressive disorder (DSM-IV) were included. Twenty patients (70 percent females, 71 ± 3 years) were divided into an exercise group (pharmacological treatment plus aerobic training) and a control group (undergoing pharmacological treatment) in a quasi-experimental design. Pharmacological treatment was maintained stable throughout the study (antidepressants and anxiolytics). Subjects were evaluated by depression scales (Beck Depression Inventory, Hamilton Depression Rating Scale, Montgomery-Asberg Depression Rating Scale) and the Short Form Health Survey-36, and electroencephalographic measurements (frontal and parietal alpha asymmetry) before and after 1 year of treatment. After 1 year, the control group showed a decrease in cortical activity on the right hemisphere (increase of alpha power), which was not observed in the exercise group. The exercise group showed a significant decrease of depressive symptoms, which was not observed in the control group. This result was also accompanied by improved treatment response and remission rate after 1 year of aerobic exercise associated with treatment. This study provides support for the effect of aerobic training on alpha activity and on depressive symptoms in elderly patients. Exercise facilitates the treatment of depressive elderly adults, leading to clinical and physical improvement and protecting against a decrease in cortical activity.
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Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ritmo alfa , Trastorno Depresivo Mayor/terapia , Terapia por Ejercicio/métodos , Calidad de Vida , Ansiolíticos/uso terapéutico , Antidepresivos/uso terapéutico , Terapia Combinada , Trastorno Depresivo Mayor/psicología , Electroencefalografía , Estudios de Seguimiento , Escalas de Valoración PsiquiátricaRESUMEN
The effect of physical exercise on the treatment of depressive elderly adults has not been investigated thus far in terms of changes in cortical hemispheric activity. The objective of the present study was to identify changes in depressive symptoms, quality of life, and cortical asymmetry produced by aerobic activity. Elderly subjects with a diagnosis of major depressive disorder (DSM-IV) were included. Twenty patients (70% females, 71 +/- 3 years) were divided into an exercise group (pharmacological treatment plus aerobic training) and a control group (undergoing pharmacological treatment) in a quasi-experimental design. Pharmacological treatment was maintained stable throughout the study (antidepressants and anxiolytics). Subjects were evaluated by depression scales (Beck Depression Inventory, Hamilton Depression Rating Scale, Montgomery-Asberg Depression Rating Scale) and the Short Form Health Survey-36, and electroencephalographic measurements (frontal and parietal alpha asymmetry) before and after 1 year of treatment. After 1 year, the control group showed a decrease in cortical activity on the right hemisphere (increase of alpha power), which was not observed in the exercise group. The exercise group showed a significant decrease of depressive symptoms, which was not observed in the control group. This result was also accompanied by improved treatment response and remission rate after 1 year of aerobic exercise associated with treatment. This study provides support for the effect of aerobic training on alpha activity and on depressive symptoms in elderly patients. Exercise facilitates the treatment of depressive elderly adults, leading to clinical and physical improvement and protecting against a decrease in cortical activity.
Asunto(s)
Ritmo alfa , Trastorno Depresivo Mayor/terapia , Terapia por Ejercicio/métodos , Calidad de Vida , Anciano , Ansiolíticos/uso terapéutico , Antidepresivos/uso terapéutico , Terapia Combinada , Trastorno Depresivo Mayor/psicología , Electroencefalografía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Escalas de Valoración PsiquiátricaRESUMEN
Caffeine is the most consumed psychoactive substance in the world. The effects of caffeine have been studied using cognitive and motor measures, quantitative electroencephalography (qEEG) and event-related potentials. However, these methods are not usually employed in combination, a fact that impairs the interpretation of the results. The objective of the present study was to analyze changes in electrophysiological, cognitive and motor variables with the ingestion of caffeine, and to relate central to peripheral responses. For this purpose we recorded event-related potentials and eyes-closed, resting EEG, applied the Stroop test, and measured reaction time. Fifteen volunteers took caffeine (400 mg) or placebo in a randomized, crossover, double-blind design. A significant reduction of alpha absolute power over the entire scalp and of P300 latency at the Fz electrode were observed after caffeine ingestion. These results are consistent with a stimulatory effect of caffeine, although there was no change in the attention (Stroop) test or in reaction time. The qEEG seems to be the most sensitive index of the changes produced by caffeine in the central nervous system since it proved to be capable of detecting changes that were not evident in the tests of cognitive or motor performance.
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Cafeína/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Sistema Nervioso Central/efectos de los fármacos , Cognición/efectos de los fármacos , Electroencefalografía/efectos de los fármacos , Desempeño Psicomotor/efectos de los fármacos , Adulto , Análisis de Varianza , Estudios Cruzados , Método Doble Ciego , Electrofisiología , Potenciales Relacionados con Evento P300/efectos de los fármacos , Femenino , Humanos , Masculino , Tiempo de ReacciónRESUMEN
Caffeine is the most consumed psychoactive substance in the world. The effects of caffeine have been studied using cognitive and motor measures, quantitative electroencephalography (qEEG) and event-related potentials. However, these methods are not usually employed in combination, a fact that impairs the interpretation of the results. The objective of the present study was to analyze changes in electrophysiological, cognitive and motor variables with the ingestion of caffeine, and to relate central to peripheral responses. For this purpose we recorded event-related potentials and eyes-closed, resting EEG, applied the Stroop test, and measured reaction time. Fifteen volunteers took caffeine (400 mg) or placebo in a randomized, crossover, double-blind design. A significant reduction of alpha absolute power over the entire scalp and of P300 latency at the Fz electrode were observed after caffeine ingestion. These results are consistent with a stimulatory effect of caffeine, although there was no change in the attention (Stroop) test or in reaction time. The qEEG seems to be the most sensitive index of the changes produced by caffeine in the central nervous system since it proved to be capable of detecting changes that were not evident in the tests of cognitive or motor performance.
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Adulto , Femenino , Humanos , Masculino , Cafeína/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Sistema Nervioso Central/efectos de los fármacos , Cognición/efectos de los fármacos , Electroencefalografía/efectos de los fármacos , Desempeño Psicomotor/efectos de los fármacos , Análisis de Varianza , Estudios Cruzados , Método Doble Ciego , Electrofisiología , /efectos de los fármacos , Tiempo de ReacciónRESUMEN
Using in vivo microdialysis, we compared the effects of tianeptine (an antidepressant drug which, in marked contrast with other antidepressants, is thought to increase the uptake of serotonin (5-hydroxytryptamine, 5-HT) on extracellular 5-HT concentrations ([5-HT](ext)) in the frontal cortex and raphe nuclei of freely moving rats with those of paroxetine, a potent selective serotonin reuptake inhibitor. A single paroxetine dose (1 mg/kg, i.p.) increased [5-HT](ext) over baseline in the frontal cortex and raphe nuclei, respectively. A single administration of tianeptine (10 mg/kg, i.p.) did not change [5-HT(ext)] in the two brain regions studied. Repeated exposure to paroxetine (0.5 mg/kg) b.i.d. for 14 days induced a sixfold significant increase in basal [5-HT](ext) in the raphe nuclei. Administration of tianeptine (5 mg/kg) b.i.d. for 14 days did not affect 5-HT baseline concentrations. In rats chronically treated with either paroxetine or tianeptine, drug challenge did not alter area under the curve values. Thus, our in vivo data indicate that tianeptine and paroxetine do not exert a similar in vivo effect on the serotonergic system in rat brain.
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Antidepresivos Tricíclicos/farmacología , Serotonina/metabolismo , Tiazepinas/farmacología , Animales , Relación Dosis-Respuesta a Droga , Lóbulo Frontal/efectos de los fármacos , Lóbulo Frontal/metabolismo , Masculino , Microdiálisis , Paroxetina/farmacología , Núcleos del Rafe/efectos de los fármacos , Núcleos del Rafe/metabolismo , Ratas , Ratas Sprague-Dawley , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Factores de TiempoRESUMEN
We investigated whether the antidepressant tianeptine shares the dopamine uptake inhibitory properties of the chemically related antidepressant amineptine. Tianeptine dose dependently (5, 10, 20, 40 mg/kg IP) increased locomotor activity in mice. This stimulant effect (20 mg/kg IP) was dose dependently prevented not only by the D1 dopamine receptor antagonist SCH 23390 (7.5. 15, 30 microg/kg SC), but also by the D2 dopamine receptor antagonist haloperidol (50, 100, 200 microg/kg IP), in contrast to that elicited by dopamine uptake inhibitors. Where the latter prevent dexamphetamine-induced (3 mg/kg SC) reversion of akinesia in mice pretreated with reserpine (4 mg/kg SC, 5 h before test), tianeptine (20 mg/kg IP, 30 min before test) did not. Tested up to a concentration of 10-4 M, tianeptine did neither inhibit the [3H]dopamine uptake into mouse striatal synaptosomes nor compete in vitro with the specific binding of [3H]WIN 35,428 at dopamine transporters from striatal membranes. Finally, in mice injected IV with a tracer dose of [3H]WIN 35,428 (1 microCi), the highest tested dose of tianeptine (40 mg/kg IP) did not reduce the specific binding of the radioligand to striatal dopamine transporters. It is concluded that the antidepressant effect of tianeptine does not depend upon a blockade of the neuronal dopamine transporter.
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Antidepresivos Tricíclicos/química , Antidepresivos Tricíclicos/farmacología , Dibenzocicloheptenos/química , Dibenzocicloheptenos/farmacología , Inhibidores de Captación de Dopamina/química , Inhibidores de Captación de Dopamina/farmacología , Tiazepinas/química , Tiazepinas/farmacología , Animales , Antidepresivos Tricíclicos/administración & dosificación , Benzazepinas/administración & dosificación , Benzazepinas/farmacología , Cocaína/análogos & derivados , Cocaína/metabolismo , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Dextroanfetamina/administración & dosificación , Dextroanfetamina/farmacología , Dibenzocicloheptenos/administración & dosificación , Dopamina/metabolismo , Inhibidores de Captación de Dopamina/administración & dosificación , Interacciones Farmacológicas , Haloperidol/administración & dosificación , Haloperidol/farmacología , Técnicas In Vitro , Masculino , Ratones , Actividad Motora/efectos de los fármacos , Ensayo de Unión Radioligante , Tiazepinas/administración & dosificaciónRESUMEN
Both repeated stress and corticosterone administration induce remodeling of apical dendrites of hippocampal CA3 pyramidal neurons. Circulating glucocorticoids are involved in the mechanism that produces atrophy, along with excitatory amino acids and serotonin (5-hydroxytryptamine, 5-HT). We used 5-HT-related antidepressants and a benzodiazepine in order to explore indirectly the role of serotonin and GABA(A)-benzodiazepine receptors in the stress-induced structural changes visualized by the Golgi impregnation of the rat hippocampus. The 5-HT reuptake enhancer (+/-)-tianeptine prevented the dendritic atrophy caused by repeated restraint stress in a non-stereoselective fashion and two 5-HT reuptake antagonists, fluoxetine and fluvoxamine, failed to block dendritic atrophy. Tianeptine also functions as a therapeutic tool since it reversed the already established hippocampal atrophy caused by treatment with corticosterone for 3 weeks. Finally, the benzodiazepine agonist adinazolam was effective in preventing the stress-induced dendritic atrophy. These findings suggest that the synaptic availability of 5-HT is involved in the mechanism leading to stress-induced dendritic remodeling and supports the idea that the hippocampal inhibitory GABAergic tone may play a regulatory role.
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Antidepresivos de Segunda Generación/farmacología , Hipocampo/efectos de los fármacos , Receptores de GABA-A/fisiología , Tiazepinas/farmacología , Animales , Antidepresivos Tricíclicos/farmacología , Células Dendríticas/efectos de los fármacos , Células Dendríticas/ultraestructura , Fluoxetina/farmacología , Fluvoxamina/farmacología , Aparato de Golgi/efectos de los fármacos , Aparato de Golgi/ultraestructura , Hipocampo/fisiología , Masculino , Células Piramidales/efectos de los fármacos , Células Piramidales/ultraestructura , Ratas , Ratas Sprague-Dawley , Receptores de Serotonina/fisiología , Restricción Física/efectos adversos , Estrés Fisiológico/inducido químicamente , Estrés Fisiológico/fisiopatologíaRESUMEN
We compared the effects of nifedipine and diltiazem on the uptake of cefpodoxime proxetil (CP). The study was aimed at establishing the impact of increased mesenteric blood flow due to calcium channel blockers on passive transport. Twelve volunteers were given CP (200 mg) orally in a crossover design. The absorption, disposition, and elimination parameters of cefpodoxime were compared among the following three treatment groups: CP alone, CP following oral administration of diltiazem (60 mg), or CP following oral administration of nifedipine (20 mg). No statistically significant difference in pharmacokinetic parameters was observed between the three treatment groups.
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Antibacterianos/farmacocinética , Bloqueadores de los Canales de Calcio/farmacología , Ceftizoxima/análogos & derivados , Diltiazem/farmacología , Nifedipino/farmacología , Administración Oral , Adulto , Antibacterianos/sangre , Ceftizoxima/sangre , Ceftizoxima/farmacocinética , Estudios Cruzados , Interacciones Farmacológicas , Humanos , Masculino , Circulación Esplácnica/efectos de los fármacos , Cefpodoxima ProxetiloRESUMEN
A selective HPLC method is described for the determination of cefpodoxime levels in plasma and sinus mucosa. Sample preparation included solid-phase extraction with a C8 cartridge. Cefpodoxime and cefaclor (internal standard) were eluted with methanol and analyzed on an optimised system consisting of a C18 stationary phase and a ternary mobile phase (0.05 M acetate buffer pH 3.8-methanol-acetonitrile, 87:103, v/v) monitored at 235 nm. Linearity and both between- and within-day reproducibility were assessed for plasma and sinus mucosa samples. Inter-assay coefficients of variation were lower than 13.6% (n = 10) for plasma (0.2 micrograms/ml) and lower than 12.4% (n = 5) for sinus mucosa (0.25 micrograms/g). The quantification limit was 0.05 micrograms/ml for plasma and 0.13 micrograms/g for tissue. The method was used to study the diffusion of cefpodoxime in sinus mucosa.
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Ceftizoxima/análogos & derivados , Senos Paranasales/química , Ceftizoxima/análisis , Ceftizoxima/sangre , Ceftizoxima/farmacocinética , Cromatografía Líquida de Alta Presión , Humanos , Membrana Mucosa/química , Espectrofotometría Ultravioleta , CefpodoximaRESUMEN
Previous experiments have shown that chronic ethanol consumption in mice for 12 months produced memory deficits associated with both alterations in diencephalic structures (ie, cellular loss, hypometabolism, particularly in mamillary bodies) and with hippocampal and cortical cholinergic hypofunction (Béracochéa et al., Pharmacol Biochem Behav 1992; 42: 749-53). The present study was aimed at comparing the effects of tianeptine and paroxetine (10 mg.kg-1, i.p.), that have opposite properties on serotoninergic transmission, on this alcohol-induced memory deficits. For this purpose, animals were submitted to a T-maze sequential alternation task in which they were given daily series of 6 successive trials separated by a 30-second interval. Behavioural testing began following a 4-week complete withdrawal period. The experiment was conducted in two steps. In the first part, animals received no treatment. Results showed that, as compared to the control group (pair-fed, n = 7), alcohol-treated mice (n = 20) displayed a trial-specific impairment of alternation rates. Specifically, they were impaired on the last three trials (4-6) of the series (52.2 vs 81.0%, p < 0.001), but performed normally on the first ones (2-3), suggesting thereby an increased sensitivity to proactive interference (Béracochéa et al., Behav Brain Res 1987; 25: 63-74). In the second part of the experiment the alcohol group was divided into three homogeneous groups according to the treatment they received 30 minutes before each daily session (ie, placebo, tianeptine, paroxetine).(ABSTRACT TRUNCATED AT 250 WORDS)
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Trastorno Amnésico Alcohólico/fisiopatología , Antidepresivos Tricíclicos/farmacología , Recuerdo Mental/efectos de los fármacos , Paroxetina/farmacología , Tiazepinas/farmacología , Animales , Encéfalo/efectos de los fármacos , Encéfalo/fisiopatología , Aprendizaje Discriminativo/efectos de los fármacos , Aprendizaje Discriminativo/fisiología , Relación Dosis-Respuesta a Droga , Masculino , Recuerdo Mental/fisiología , Ratones , Ratones Endogámicos BALB C , Orientación/efectos de los fármacos , Orientación/fisiología , Retención en Psicología/efectos de los fármacos , Retención en Psicología/fisiología , Serotonina/fisiologíaRESUMEN
We studied the action of nifedipine on the bioavailability of cefixime, a molecule absorbed via the gut wall dipeptide carrier system in the rat, and on the bioavailability of D-xylose, which is absorbed via a pH (and Na(+)-)-dependent transporter. Each compound was administered alone or in combination with 20 mg of nifedipine to eight healthy male volunteers. Nifedipine significantly increased the absorption rate of cefixime (20.7 +/- 4.3 versus 16 +/- 3.5 mg/h in the absence of nifedipine). The absolute bioavailability of cefixime alone was 31% +/- 6% compared with 53% +/- 1% (P < 0.01) in the presence of nifedipine. The observed peak concentrations in serum were significantly different (2.5 +/- 0.3 mg/liter without nifedipine and 3.7 +/- 1.1 mg/liter with nifedipine; P < 0.02). In contrast, nifedipine induced no significant differences in the pharmacokinetic profile of xylose following oral administration. We conclude that (i) cefixime is absorbed in humans by an apparently active process which can be enhanced by a calcium channel blocker, in this case, nifedipine; and (ii) nifedipine does not modify the activity of the pentose transporter.
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Cefotaxima/análogos & derivados , Dipéptidos/farmacocinética , Nifedipino/farmacología , Administración Oral , Adulto , Disponibilidad Biológica , Transporte Biológico Activo/efectos de los fármacos , Cefixima , Cefotaxima/farmacocinética , Portadores de Fármacos/metabolismo , Humanos , Concentración de Iones de Hidrógeno , Inyecciones Intravenosas , Absorción Intestinal/efectos de los fármacos , Masculino , Sensibilidad y Especificidad , Xilosa/farmacocinéticaRESUMEN
We have developed a specific numerical deconvolution program for the Apple Macintosh microcomputer. After comparison with other methods, we used the program to evaluate the influence of nifedipine on the absorption and bioavailability of amoxicillin. The technique provided a model-independent approach. This study shows that the simultaneous administration of nifedipine with amoxicillin leads to a significant increase in both the total quantity of amoxicillin absorbed (+22%) and the rate of absorption. Parameters of clearance, volume of distribution, and elimination were unaffected. Numerical deconvolution analysis showed that nifedipine did not modify the absorption kinetics of amoxicillin, which are characterized by a lag time followed by a constant rate of absorption, suggesting zero-order kinetics with first-order kinetics at the end of the process. The results suggest the existence of a specialized, saturable transport molecule for this antibiotic.
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Amoxicilina/farmacocinética , Absorción Intestinal/fisiología , Programas Informáticos , Adulto , Disponibilidad Biológica , Humanos , Inyecciones Intravenosas , Absorción Intestinal/efectos de los fármacos , Masculino , Cómputos Matemáticos , Microcomputadores , Nifedipino/farmacología , Distribución Tisular/efectos de los fármacosRESUMEN
Interest in the intestinal absorption mechanisms of drugs has increased because transepithelial passage across the gut does not necessarily follow a passive diffusion process. Amoxycillin, like other amino-beta-lactam antibiotics, has been demonstrated in vitro to use the dipeptide carrier-mediated system in rodent small intestine. In order to assess the in-vivo relevance of these data, we applied the Loo-Riegelman method for a reappraisal of amoxycillin absorption kinetics in healthy human volunteers. The results showed evidence of a saturable carrier-mediated uptake of this antibiotic. With respect to the in-vitro data previously published, the dipeptide carrier system would appear to be the most likely transport mechanism.
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Amoxicilina/farmacocinética , Absorción Intestinal , Administración Oral , Adulto , Amoxicilina/administración & dosificación , Amoxicilina/sangre , Disponibilidad Biológica , Portadores de Fármacos , Humanos , Inyecciones Intravenosas , Masculino , Análisis de RegresiónRESUMEN
Intestinal absorption of aminopenicillins in vitro uses the dipeptide carrier system. Recent experiments have reported calcium ion to be a cellular mediator of the regulation of electrolyte transport through the enterocyte membrane, especially the Na/H exchange which is partly responsible for the proton gradient energizing the carrier system. In order to assess the in vivo relevance of these data, we studied, in healthy volunteers, the influence of nifedipine, a calcium channel blocking agent, on the intestinal uptake of amoxicillin, a commonly prescribed and well-absorbed aminopenicillin. Results obtained show that 1) intestinal absorption kinetics of amoxicillin follows a zero-order process, which further substantiates the existence of a saturable carrier-mediated process for this antibiotic in humans and 2) calcium channel blockade significantly enhances both absorption rate (by 70%) and bioavailability of amoxicillin (by 21.4%) without modifying its distribution or elimination. These findings might suggest that nifedipine could enhance amoxicillin intestinal uptake by stimulating its active transport.