A Differential Thermal Lens Spectrometry Method for Trace Detection.

Thermal lens spectroscopy (TLS) is a high-sensitivity method to determine the concentration of light-absorbing species in samples. Here, we implemented a transient configuration of the technique, with a focused pump and a collimated probe beam coaxially propagating. A Fabry-Perot optical resonator is incorporated allowing multi-passing of the probe beam through the sample to enhance sensitivity. We show how the low detection limit of the method can be reduced approximately by half by making differential measurements of the signal at a far field in the center point of the probe beam spot and that obtained by spatial filtering of the same beam, the so-called eclipsed signal. Measurements were performed in test samples of Deyman's organic dye, Strawberry 2143 v.7, dissolved in ethanol. The thermal lens signal measured as a function of the dye concentration in water at the center of the beam was compared with the differential signal resulting from this and the eclipsed beam.

Los efectos de la inteligencia emocional, la legitimidad y la disuasión en la conducta antisocial / The effects of emotional intelligence, legitimacy and deterrence on antisocial behavior

Resumen Investigaciones previas sugieren que las conductas antisociales y delictivas son más prevalentes en individuos que presentan una baja inteligencia emocional, así como en aquellos que perciben una baja probabilidad de sanción y una nula legitimidad de las autoridades. El objetivo de esta investigación rue analizar los efectos de la inteligencia emocional, la disuasión (específicamente la percepción de probabilidad de recibir sanción) y la legitimidad de las autoridades en la conducta antisocial en reclusos en comparación con un grupo control. El grupo de reclusos estuvo compuesto por 105 sujetos provenientes de un Centro de Reinserción Social de una ciudad del noroeste de México, con una media de edad de 32.03 años (DE = 8.986); y el grupo control, por 105 adultos sin antecedentes penales, con una media de edad de 32.08 años (DE= 10.094). Ambas muestras seleccionadas por conveniencia. Los resultados mostraron diferencias significativas en las escalas de inteligencia emocional (t = -4.14, p < .001), legitimidad (t = -3.09, p < .01) y probabilidad de castigo (t = -4.66, p < .001): específicamente, la d de Cohen indicó que la muestra control presentó mayor inteligencia emocional (d=-0.81), mayor percepción de legitimidad (d=-0.60) y mayor percepción de probabilidad de sanción (d=-0.90) en contraste con la muestra de reclusos. Dentro del modelo de ecuaciones estructurales, las variables de inteligencia emocional y percepción de probabilidad de castigo influyeron en el comportamiento antisocial, lo cual indica que posiblemente las competencias emocionales podrían repercutir sobre el temor de recibir alguna sanción ante la comisión de determinadas conductas antisociales.

Abstract Previous research suggests that antisocial and criminal behaviors are more prevalent in individuals with low emotional intelligence, as well as in those who perceive a low probability of punishment and no legitimacy of authorities. The aim of this research was to analyze the effects of emotional intelligence, deterrence (specifically, the perception of the probability of receiving a sanction), and the legitimacy of authorities on antisocial behavior in inmates compared to a control group. The group of inmates was composed of 105 adults from a Social Reinsertion Center in a city in northwestern Mexico, with a mean age of 32.03 years (SD = 8.986); and the control group was composed of 105 adults with no criminal record, with a mean age of 32.08 years (SD = 10.094). Both samples were selected by convenience. Significant differences were detected in the scales of emotional intelligence (t = -4.14, p <.001), legitimacy (t = -3.09, p <.01), and probability of punishment (t = -4.66, p <.001). The control group presented higher emotional intelligence (d = -0.81), higher perception of legitimacy (d = -0.60), and higher perception of probability of punishment (d = -0.90) in contrast to the inmate sample. A Structural Equations Model (SEM) showed that emotional intelligence and perceived probability of punishment influenced antisocial behavior, which indicates that emotional competences may have an impact on the fear of being sanctioned when committing certain antisocial behaviors.

Elevation of GABA levels in the globus pallidus disinhibits the thalamic reticular nucleus and desynchronized cortical beta oscillations.

The external globus pallidus (GP) is a GABAergic node involved in motor control regulation and coordinates firing and synchronization in the basal ganglia-thalamic-cortical network through inputs and electrical activity. In Parkinson's disease, high GABA levels alter electrical activity in the GP and contribute to motor symptoms. Under normal conditions, GABA levels are regulated by GABA transporters (GATs). GAT type 1 (GAT-1) is highly expressed in the GP, and pharmacological blockade of GAT-1 increases the duration of currents mediated by GABA A receptors and induces tonic inhibition. The functional contribution of the pathway between the GP and the reticular thalamic nucleus (RTn) is unknown. This pathway is important since the RTn controls the flow of information between the thalamus and cortex, suggesting that it contributes to cortical dynamics. In this work, we investigated the effect of increased GABA levels on electrical activity in the RTn by obtaining single-unit extracellular recordings from anesthetized rats and on the motor cortex (MCx) by corticography. Our results show that high GABA levels increase the spontaneous activity rate of RTn neurons and desynchronize oscillations in the beta frequency band in the MCx. Our findings provide evidence that the GP exerts tonic control over RTn activity through the GP-reticular pathway and functionally contributes to cortical oscillation dynamics.

Temporally irregular electrical stimulation to the epileptogenic focus delays epileptogenesis in rats.

BACKGROUND: Variation in the temporal patterns of electrical pulses in stimulation trains has opened a new field of opportunity for the treatment of neurological disorders, such as pharmacoresistant temporal lobe epilepsy. Whether this novel type of stimulation affects epileptogenesis remains to be investigated. OBJECTIVE: The purpose of this study was to analyze the effects of temporally irregular deep brain stimulation on kindling-induced epileptogenesis in rats. METHODS: Temporally irregular deep brain stimulation was delivered at different times with respect to the kindling stimulation. Behavioral and electrographic changes on kindling acquisition were compared with a control group and a temporally regular deep brain stimulation-treated group. The propagation of epileptiform activity was analyzed with wavelet cross-correlation analysis, and interictal epileptiform discharge ratios were obtained. RESULTS: Temporally irregular deep brain stimulation delivered in the epileptogenic focus during the interictal period shortened the daily afterdischarge duration, slowed the progression of seizure stages, diminished the generalized seizure duration and interfered with the propagation of epileptiform activity from the seizure onset zone to the ipsi- and contralateral motor cortex. We also found a negative correlation between seizure severity and interictal epileptiform discharges in rats stimulated with temporally irregular deep brain stimulation. CONCLUSION: These results provide evidence that temporally irregular deep brain stimulation interferes with the establishment of epilepsy by delaying epileptogenesis by almost twice as long in kindling animals. Thus, temporally irregular deep brain stimulation could be a preventive approach against epilepsy.

Transcranial focal electrical stimulation via concentric ring electrodes in freely moving cats: Antiepileptogenic and postictal effects.

Transcranial focal electrical stimulation (TFS) via tripolar concentric ring electrodes (TCRE), tripolar TFS, is proposed to treat pharmacoresistant epilepsy. We determined the effect of tripolar TFS on electrical amygdaloid kindling (AK) in freely moving cats. Fifteen cats were bilaterally implanted with electrodes in the amygdala (AM) and prefrontal cortex and assigned to three groups: the control group, which only received AK; the tripolar TFS before AK group, in which TCREs were placed over the vertex and tripolar TFS (300 Hz, 200 µs biphasic equal charge, square pulses) was delivered for 40 min just prior to AK; and the tripolar TFS after AK group, in which the TCREs were placed over the temporal bone ipsilateral to the kindled AM, while tripolar TFS was administered for 2 min just after AK onset for 40 days, and, thereafter, only AK was applied. AK was applied daily until all animals reached kindling stage VI. A three concentric spheres finite element cat head model was developed to analyze the electric fields caused by tripolar TFS. Tripolar TFS after AK inhibited kindling development. Animals with tripolar TFS after AK remained at the focal seizure stages for 20 days after tripolar TFS cessation and required 80.0 ±â€¯15.42 AK stimulations to reach stage VI, significantly higher than TFS before AK, and control (P < .001). Tripolar TFS before AK did not show signs of protection against epileptogenesis. The finite modeling of tripolar TFS showed that the electric field is >0.3 mV/mm at depths less than approximately 12.6 mm in the cat brain, which should be strong enough to alter brain activity. In conclusion, tripolar TFS applied via a TCRE over the ipsilateral temporal area significantly delayed AK. This taken together with other reports of tripolar TFS aborting seizures in acute seizure models suggests that tripolar TFS is a promising new modality that should be considered for further testing.

Effects of High- and Low-Frequency Stimulation of the Thalamic Reticular Nucleus on Pentylentetrazole-Induced Seizures in Rats.

RATIONALE: The use of electrical stimulation therapy to treat epilepsy is currently being studied in experimental animals and patients. Our study was designed to evaluate the effects of electrical stimulation applied in the thalamic reticular nucleus (TRN) on the development of pentylentetrazole-induced seizures. MATERIALS AND METHODS: Experiments were performed using male Wistar rats with electrodes stereotaxically implanted in the left TRN. Epidural EEG recording screws were implanted in the motor cortex for EEG recording. The rats were classified in seven groups: one sham group, four groups receiving either high- or low-frequency preemptive stimulation for either 10 or 60 minutes, and two groups receiving either high- or low-frequency responsive stimulation for ten minutes. All animals received a single dose of pentylentetrazole throughout five days. EEG recordings were obtained from the cortex and were evaluated to assess ictal behavior more than 45 to 90 minutes. RESULTS: Ten minutes of preemptive high-frequency stimulation in the TRN induced a significant decrease in seizure severity compared to 60 minutes of preemptive stimulation and ten minutes of responsive stimulation. Additionally, ten minutes of preemptive high-frequency stimulation protected against death as aftereffect of status epilepticus. The spike-wave complex frequency was not modified. CONCLUSIONS: These data could contribute to the characterization of the TRN in mediating the initiation and spreading of seizure activity and provide preclinical support for optimal parameters to use to obtain beneficial effects against convulsive activity.

Short-term deep brain stimulation of the thalamic reticular nucleus modifies aberrant oscillatory activity in a neurodevelopment model of schizophrenia.

Dysfunction of thalamo-cortical networks involving particularly the thalamic reticular nucleus (TRN) is implicated in schizophrenia. In the neonatal ventral hippocampal lesion (NVHL), a heuristic animal model of schizophrenia, brain oscillation changes similar to those of schizophrenic patients have been reported. The aim of this study was to analyze the effects of short-term deep brain stimulation (DBS) in the thalamic reticular nucleus on electroencephalographic (EEG) activity in the NVHL. Male and female Sprague-Dawley rats were used and the model was prepared by excitotoxicity damage of the ventral hippocampus on postnatal day 7 (PD-7). Chronic bilateral stainless steel electrodes were implanted in the TRN, thalamic dorsomedial nucleus and prelimbic area at PD-90. Rats were classified as follows: sham and NVHL groups, both groups received bilateral DBS in the TRN for one hour (100Hz, 100µs pulses, 200µA). All animals showed a sudden behavioral arrest accompanied by widespread symmetric bilateral spike-wave discharges, this activity was affected by DBS-TRN. Additionally, the power spectra of 0.5-100Hz and the coherence of 0.5-4.5 and 35-55Hz frequencies were modified by DBS-TRN. Our results suggest that DBS in the TRN may modify functional connectivity between different parts of the thalamo-cortical network. Additionally, our findings may suggest a beneficial effect of DBS-TRN on some preclinical aberrant oscillatory activities in a neurodevelopmental model of schizophrenia.

Justicia spicigera Schltdl. and kaempferitrin as potential anticonvulsant natural products.

Justicia spicigera Schltdl. is a vegetal species traditionally used to control epilepsy, but scientific evidence is required to reinforce this activity. The aim of the study was to evaluate the anticonvulsant-like activity of J. spicigera aqueous extract (JsAE) and a bioactive compound. JsAE was assessed in a dose-response manner (30, 100 and 1000mg/kg, i.p.) using the pentylenetetrazol (PTZ)-induced seizures and maximal electroshock seizure (MES) test in mice in comparison to ethosuximide (ETX, reference drug 100mg/kg, i.p.) or phenytoin (25mg/kg, i.p.), respectively. Then a significant dosage (1000mg/kg, i.p.) was chosen to examine electrographic activity (EEG) in rats. Treatment groups were compared to the vehicle and ETX in the convulsive behavior alone or simultaneous to EEG after PTZ-induced seizures (80 or 35mg/kg, i.p., mice or rats). Kaempferitrin (a flavonoid of JsAE) and ETX were administered via intracerebroventricular (i.c.v, 4th ventricle, 1µg/µL) and tested in the presence of PTZ in rats. Results confirmed that JsAE delayed the onset of seizures and reduced frequency of tonic convulsion and mortality in mice. JsAE or kaempferitrin also decreased the EEG spikes frequency and amplitude in a similar manner than EXT in rats. In conclusion, these preliminary data give evidence of the potential of J. spicigera as possible anticonvulsant as recommended in folk medicine for treating epilepsy, where kaempferitrin is suggested as a partial responsible bioactive compound.

Acute deep brain stimulation in the thalamic reticular nucleus protects against acute stress and modulates initial events of adult hippocampal neurogenesis.

Deep brain stimulation (DBS) is used as an alternative therapeutic procedure for pharmacoresistant psychiatric disorders. Recently the thalamic reticular nucleus (TRN) gained attention due to the description of a novel pathway from the amygdala to this nucleus suggesting that may be differentially disrupted in mood disorders. The limbic system is implicated in the regulation of these disorders that are accompanied by neuroplastic changes. The hippocampus is highly plastic and shows the generation of new neurons, process affected by stress but positively regulated by antidepressant drugs. We explored the impact of applying acute DBS to the TRN (DBS-TRN) in male Wistar rats exposed to acute stress caused by the forced-swim Porsolt's test (FST) and on initial events of hippocampal neurogenesis. After the first session of forced-swim, rats were randomly subdivided in a DBS-TRN and a Sham group. Stimulated rats received 10min of DBS, thus the depressant-like behavior reflected as immobility was evaluated in the second session of forced-swim. Locomotricity was evaluated in the open field test. Cell proliferation and doublecortin-associated cells were quantified in the hippocampus of other cohorts of rats. No effects of electrode implantation were found in locomotricity. Acute DBS-TRN reduced immobility in comparison to the Sham group (p<0.001). DBS-TRN increased cell proliferation (Ki67 or BrdU-positive cells; p=0.02, p=0.02) and the number of doublecortin-cells compared to the Sham group (p<0.02). Similar effects were found in rats previously exposed to the first session of forced-swim. Our data could suggest that TRN brain region may be a promising target for DBS to treat intractable depression.

White light photothermal lens spectrophotometer for the determination of absorption in scattering samples.

We developed a pump-probe photothermal lens spectrophotometer that uses a broadband arc-lamp and a set of interference filters to provide tunable, nearly monochromatic radiation between 370 and 730 nm as the pump light source. This light is focused onto an absorbing sample, generating a photothermal lens of millimeter dimensions. A highly collimated monochromatic probe light from a low-power He-Ne laser interrogates the generated lens, yielding a photothermal signal proportional to the absorption of light. We measure the absorption spectra of scattering dye solutions using the device. We show that the spectra are not affected by the presence of scattering, confirming that the method only measures the absorption of light that results in generation of heat. By comparing the photothermal spectra with the usual absorption spectra determined using commercial transmission spectrophotometers, we estimate the quantum yield of scattering of the sample. We discuss applications of the device for spectroscopic characterization of samples such as blood and gold nanoparticles that exhibit a complex behavior upon interaction with light.

Effect of vagus nerve stimulation on electrical kindling in different stages of seizure severity in freely moving cats.

Vagus nerve stimulation (VNS) is an adjunctive therapy for treating pharmacoresistant epilepsy. The present study analyze the effect of VNS on the epileptic activity of amygdala kindling (AK) in different seizure severity stages in freely moving cats. Fourteen adult male cats were used and were stereotaxically implanted in both amygdalae, in thalamic reticular nuclei and in prefrontal cortices. AK was developed by the application of 60Hz pulse trains that were one second in duration. VNS was applied the following day after the first stages were reached. This stimulation consisted of 10 pulse trains in the one-hour period (1min on/5min off) prior to AK. AK stimulation continued until all animals reached stage VI. The behavioral changes induced by VNS were transient and bearable. The animals showed relaxation of the nictitating membrane, ipsilateral anisocoria, swallowing and licking. Intermittent VNS application in stage I induced a delay in AK progression. The effect of VNS on the amygdala afterdischarge duration (AD) did not change progressively. VNS in stages II, III, and IV does not have an inhibitory effect on AK, and the AD further exhibited a progressive development. At the end of the generalized seizures, the animals presented with synchronized bilateral discharges of the spike-wave type (3Hz) and a behavioral "staring spell". Our results show that VNS applied during the different stages of seizure severity exerts an anti-epileptogenic effect in stage I but no anti-epileptogenic effect in stages II, III, and IV. These results suggest that VNS applied at stage I of kindling induces a delay of generalized convulsive activity.

Association of depression and anxiety on quality of life, treatment adherence, and prognosis in patients with advanced non-small cell lung cancer.

BACKGROUND: Symptoms of depression and anxiety are common in patients with lung cancer and may produce an impact on both health-related quality of life (HRQL) and survival. The aim of the present study was to evaluate the association of depression and anxiety on HRQL, treatment adherence, and prognosis in patients with non-small cell lung cancer (NSCLC). METHODS: This is a prospective study of patients with stage IIIB or IV NSCLC. Depression and anxiety were measured using the hospital anxiety and depression scale, the International Neuropsychiatric Interview, and the HRQL with the EORTC QLQ-C30 and QLQ-LC13 questionnaires. Instruments were applied before treatment and repeated at 3 and 6 months. Lack of treatment adherence was considered as patients who stopped going to their consultation appointments. RESULTS: A total of 82 patients were included. At the initial evaluation, depression and anxiety were found in 32.9 and 34.1 % of patients, respectively. Depression was associated with feminine gender (p = 0.034) and poor performance status (p = 0.048). Depression and anxiety showed an association with HRQL. Patients with depression showed median overall survival of 6.8 months, whereas that for nondepressed patients was 14 months (hazard ratio [HR], 1.9; 95 % confidence interval (95 % CI), 1.03-3.7; p = 0.042). The 58 % of patients with depression had poor treatment adherence versus 42 % of patients without depression (p = 0.004). CONCLUSIONS: Depression and anxiety were present in one-third of patients with recently diagnosed NSCLC. Depression and anxiety were associated with decreased HRQL scales, and depression was independently associated with treatment adherence and with poor prognosis.

Electroencephalographic activity in neonatal ventral hippocampus lesion in adult rats.

A neonatal ventral hippocampal lesion (NVHL) in rats has been commonly used as a neurodevelopmental model to mimic schizophrenia-like behaviors. Recently, we reported that NVHL resulted in dendritic retraction and spine loss in pyramidal neurons of the prefrontal cortex (PFC). In addition, the hippocampus and PFC are important structures in the regulation of the electroencephalographic (EEG) activity. Patients with PFC lesions show deficits in the EEG activity. This study aimed to determine whether the EEG activity was altered in NVHL rats. In addition, we also analyzed the locomotor activity induced by a novel environment and exploratory behavior using the hole-board test. Consistent with the behavioral findings, the EEG analysis of the cortical regions showed that the NVHL rats displayed a lower power in cortical bands. At 1-8 Hz, 9-14 Hz, and 15-30 Hz bands, our findings showed a decrease in the absolute power of the parietal and occipital cortices recordings. In addition, the NVHL rats also showed a reduction in the exploratory behavior tested using the hole-board test. In conclusion, this study demonstrated that the EEG activity was reduced in adult NVHL rats and suggests that this may play a role in the behavioral changes observed in this neurodevelopmental model of schizophrenia.

Health-related quality of life in patients with lung cancer: validation of the Mexican-Spanish version and association with prognosis of the EORTC QLQ-LC13 questionnaire.

INTRODUCTION: Lung cancer (LC) is the first cause of cancer-related mortality worldwide and health-related quality of life (HRQL) is a fundamental outcome for evaluating treatment results. Our objective was to validate the Mexican-Spanish versions of the European Organisation for Research and Treatment of Cancer (EORTC) Quality-of-Life QLQ-LC13 disease-specific questionnaire module in Mexican patients with LC; and to explore the possible prognostic role of HRQL data. METHODS: Translation procedures followed EORTC guidelines. Both instruments were completed by patients with LC. Tests for reliability and validity were performed. A subset of patients was administered HRQL evaluations before and after chemotherapy. HRQL was associated with prognosis in chemotherapy-naïve patients. The protocol was approved by the Institute's Ethics Committee. RESULTS: One hundred fifty three patients (mean age, 60.3 years; 84 females and 69 males) completed both questionnaires. Compliance rates were high, and the questionnaires were well accepted. Nine of 10 multi-item scales of both questionnaires presented Cronbach's alpha coefficients > 0.7. Multi-trait scaling analysis demonstrated good convergent and discriminant validity. Patients with better Karnofsky or Eastern Cooperative Oncology Group (ECOG) performance status reported better functional HRQL scores. Different scales in the EORTC QLQ-C30 and EORTC QLQ-LC13 questionnaires were accurately related with clinical characteristics. Functional as well as disease-symptom scales improved after chemotherapy, but treatment side-effects scales worsened in test-retest analysis. Better role functioning and absence of thoracic pain scales were associated with longer overall survival (OS) (p = 0.009 and p = 0.035, respectively). CONCLUSION: The Mexican-Spanish versions of the EORTC QLQ-C30 and EORTC QLQ-LC13 questionnaires are reliable and valid for HRQL measurement in Mexican patients with LC and can be used in clinical trials.

Histerectomía por patología benigna: ¿abordaje vaginal, laparoscópico o abdominal? ¿una decisión basada en evidencia? situación actual en Guatemala / Pathology hysterectomy: vaginal approach, laparoscopic or abdominal? A decision based on evidence? current situation in Guatemala

Mucho se ha publicado alrededor del mundo sobre medicina basada en evidencia. Se invita al médico a utilizar la evidencia científica como base para la toma de sus decisiones. Pero, ¿Se está llevando a la práctica clínica toda la evidencia científica? ¿Los objetivos educacionales de los hospitales escuela están apegados a la medicina basada en evidencia?. No existe duda que la histerectomía vaginal es la vía menos invasiva de extirpar el útero, la de recuperación más rápida, con menos morbilidad y la más costo-efectiva...

Preemptive effect of nucleus of the solitary tract stimulation on amygdaloid kindling in freely moving cats.

PURPOSE: The nucleus of the solitary tract (NTS) is a primary site where vagal afferents terminate. The aim of this study was to analyze the preemptive effect of NTS electrical stimulation on daily amygdaloid kindling (AK) in freely moving cats. METHODS: Seven adult male cats were used. Bipolar electrodes were stereotaxically implanted into both amygdalae, lateral geniculate bodies, hippocampi, and prefrontal cortices. In addition, a bipolar stainless steel electrode was implanted in the left NTS. Cats were recorded under the following experimental conditions: The NTS was stimulated for 6 days before the initiation of AK (1 min on/5 min off, 1 h total). AK was performed by stimulating the amygdala every 24 h (1 s, 60 Hz, 1 ms) until behavioral stage VI was reached. RESULTS: The number of stimulations to reach stage VI in control animals was 23.4 +/- 3.7, in lateral tegmental field (LTF) animals was 17.0 +/- 2.1 days. Animals subjected to preemptive NTS stimulation showed a significant increase (53.8 +/- 5.9). In addition, behavioral development was retarded, with an increase in the number of stimulations required to reach stage III. In this group, overall kindling development was delayed, and amygdaloid afterdischarge duration did not show a progressive increase as was observed in the control group. DISCUSSION: Our results indicate that preemptive NTS electrical stimulation interferes with epileptogenesis. This anticonvulsive effect could be related to the activation of certain structures that inhibit seizure development. Therefore, results suggest that NTS mediates the anticonvulsive effect of vagus nerve stimulation.

Effects of electrical stimulation of the vagus nerve on the development of visual habituation in the cat.

The vagus nerve participates in the control and regulation of important autonomous functions, emotional tasks, and neural activity. Electrical vagus nerve stimulation (VNS) is an approved procedure for the treatment of refractory epilepsy in humans. VNS has also been shown to improve mood complaints and cognitive function in both human patients and animals. Thus, the purpose of this study was to analyse and describe the effects of VNS on the development and establishment of sensory habituation and electrographic activity of the visual pathway in freely moving cats. Six cats had implants placed in the optic chiasm (OC), lateral geniculate body (LGB), mesencephalic reticular formation (MRF), primary visual cortex (VC) of the left hemisphere, and left vagus nerve. Immediately after surgery, all cats presented anisocoria and relaxation of the left nictitant membrane. Also showed vegetative-type responses such as myosis, licking, and swallowing during VNS. Animals were then subjected to repeated luminous stimuli at intervals of 1 and 3s to cause habituation. The effect of VNS on the frequency and latency of the habituation episodes and the electrographic changes in the registered brain structures were analysed. Latency analysis showed that VNS delayed the first habituation episode. VNS had transitory effects on the neural activity of the primary visual pathway structures, which caused a small but measurable delay in the establishment of habituation. In conclusion, VNS interferes with the development and establishment of visual habituation, an elementary form of non-associative learning, in freely moving cats.

Bioequivalence of single 100-mg doses of two oral formulations of topiramate: an open-label, randomized-sequence, two-period crossover study in healthy adult male Mexican volunteers.

BACKGROUND: The proprietary form of topiramate is indicated in Mexico as an antiepileptic agent and in the prophylaxis of migraine headaches. However, before generic topiramate is placed on the market, pharmacokinetic studies investigating the bioequivalence of generic and branded formulations are needed. OBJECTIVE: The aim of this study was to compare the bioequivalence and tolerability of a generic (test) and a branded (reference) formulation of topiramate 100 mg in healthy Mexican volunteers. METHODS: This open-label, randomized-sequence, 2-period crossover study was conducted at Ipharma SA de CV, Monterrey, Mexico. Eligible subjects were healthy male Mexican volunteers aged 18 to 45 years. Participants were randomly assigned to receive 100 mg of the test or reference formulation, followed by a 3-week washout period and administration of the alternate formulation. Doses were administered after a 12-hour overnight fast. For analysis of pharmacokinetic properties, including C(max), AUC(0-t), and AUC(0-infinity), blood samples were obtained over a 144-hour period after dosing. The formulations were to be considered bioequivalent if calculations of a 90% CI for the ratio of the means of the measures for the test and reference formulations fell within bioequivalence limits, 80% to 125%, for logarithmic (log) transformation of C(max) and AUC, and if two 1-sided t tests showed P < 0.05. Tolerability was assessed using vital sign measurement (blood pressure, body temperature, heart rate, and respiratory rate), laboratory analysis (hematology, blood biochemistry, hepatic function, and urinalysis), and subject interview. RESULTS: Twenty-eight men (mean age, 22.21 years [range, 18-28 years]; mean weight, 75.04 kg [range, 62-96 kg]; mean height, 177 cm [range, 163-192 cm]) were enrolled in this study, and 28 (14 each randomized to receive the test or reference formulation first) completed it. No period or sequence effects were observed. The 90% CIs for the log-transformed C(max), AUC(0-t) and AUC(0-infinity) were 94.70 to 112.05, 98.88 to 105.16, and 98.80 to 105.28, respectively (all, P < 0.05). No adverse events were reported by the volunteers or found on clinical laboratory testing during the study. CONCLUSIONS: This study did not find any statistically significant differences in C(max) or AUC values between the test and reference formulations of oral topiramate 100 mg in this population of healthy adult male Mexican volunteers. On that basis, and according to both the rate and extent of absorption, the test and reference formulations met the regulatory criteria for bioequivalence. Both formulations were well tolerated.

Evaluación de las necesidades de pacientes oncológicos en etapa terminal (a través del instrumento EMPOET): comparación entre muestras / Assessment of terminal cancer patients needs (through the ATCPN questionnaire): a comparison amongst different samples

El propósito del presente estudio fue el de comparar la forma en que pacientes con cáncer en etapa terminal y médicos evalúan las necesidades de este tipo de pacientes. La muestra estuvo constituida por 91 pacientes y 85 médicos seleccionados de diferentes hospitales de la Ciudad de México. Los integrantes de las muestras contestaron un cuestionario en le cual evaluaron la importancia de las necesidades médicas, psicológicas, sociales, económicas y espirituales de los pacientes. Para evaluar las necesidades de los pacientes terminales se construyó un cuestionario, Evaluación de las Necesidades de Pacientes Oncológicos en Etapa Terminal (ENPOET), basado en otros instrumentos similares y se complementó con reactivos diseñados por el grupo de investigación. El cuestionario final utilizado estuvo compuesto por 38 afirmaciones que exploraban las necesidades de los pacientes en cinco áreas diferentes: médica, psicológica, social, económica y espiritual. El cuestionario mostró ser válido, confiable y mostró una consistencia interna apropiada. Los resultados mostraron una considerable homogeneidad en las evaluaciones de las dos muestras. La necesidad evaluada más relevante para los pacientes fue “tener los médicos “no sentirse desamparado”. Los resultados se discutieron en términos de su congruencia con otros estudios sobre el tema (AU)

The purpose of the present study was to compare the way in which terminal cancer patients and their doctors assess the necessities of this particular type of patient. The sample was constituted by 91 patients. The sample was constituted by 91 patients and 85 doctors selected form different hospitals in México City. The participants from the two samples were asked to answer a printed questionnaire that assessed the relative relevance of medical, psychological, social, economic an spiritual needs of the patients. The questionnaire Assessment of Terminal Cancer Patient Needs (ATCPN) was built based on other similar questionnaires and complemented by items designed by the present work group. The final questionnaire was composed by 38 items that explored the needs of the patients in 5 different areas: medical, psychological, social, economic and spiritual. The questionnaire produced data that suggested its reliability, validity and internal consistency. The results also showed a considerable homogeneity in the assessments produced by the two samples. The highest priority of the patients was having faith in god or in a supreme being; the doctors favored the ability to cope with the feeling of being forsaken. Results were discussed in terms of their congruence with other studies on the subject (AU)

Long-term changes in sleep and electroencephalographic activity by chronic vagus nerve stimulation in cats.

We previously reported the effect of vagus nerve electrical stimulation (VNS) on sleep and behavior in cats. The aim of the present study is to analyze the long-term effects of VNS on the electroencephalographic (EEG) power spectrum and on the different stages of the sleep-wakefulness cycle in the freely moving cat. To achieve this, six male cats were implanted with electrodes on the left vagal nerve and submitted to 15 rounds of 23 h continuous sleep recordings in three categories: baseline (BL), VNS and post-stimulus recording (PSR). The following parameters were analyzed: EEG power spectrum, total time and number of sleep phases, ponto-geniculo-occipital (PGO) wave density of the rapid eye movement (REM) sleep, and the number of times the narcoleptic reflex was present (sudden transition from wakefulness to REM sleep). Significant changes were detected, such as an enhancement of slow-wave sleep (SWS) stage II; a power increase in the bands corresponding to sleep spindles (8-14 Hz) and delta waves (1-4 Hz) with VNS and PSR; an increase in the total time, number of stages, and density of PGO wave in REM sleep with VNS; a decrease of wakefulness in PSR, and the eventual appearance of the narcoleptic reflex with VNS. The results show that the effect of the VNS changes during different stages of the sleep-wakefulness cycle. In REM sleep, the effect was present only during VNS, while the SWS II was affected beyond VNS periods. This suggests that ponto-medullar and thalamic mechanisms of slow EEG activity may be due to plastic changes elicited by vagal stimulation.