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Biomedical subjects

S Tufik

Publications and source records attributed to S Tufik.

At least 19 recordsLinked to original sources
PubMed2006

Effects of paradoxical sleep deprivation on blood parameters associated with cardiovascular risk in intact and ovariectomized rats compared with male rats.

The purpose of this study was to investigate the effects of paradoxical sleep deprivation (PSD) on circulating lipoproteins (total cholesterol, HDL, LDL and triglycerides) in males as well as in intact and ovariectomized (OVX) female rats. The intact female rat group was sub-distributed according to the phase of the estrous cycle (proestrus, estrus and diestrus) allowing for comparison of the lipid profile with males and OVX rats. The results indicate that PSD significantly reduced cholesterol in intact females compared to OVX and male rats; it reduced triglycerides in all groups except in diestrus rats and increased HDL levels in male rats compared with the respective controls. PSD also increased LDL levels in male and OVX rats when compared to intact females. Examinations of cholesterol fractions revealed significant increases in HDL in control-OVX animals when compared to the other groups, whereas HDL was significantly increased after PSD in male rats. Such results suggest that the cardiovascular response in intact, OVX females and male rats is differentially regulated especially when such are submitted to PSD. Similarities in blood parameters observed between OVX and male rats are likely due to the suppression of ovarian hormone release after ovariectomy.

Animals↗
PubMed2006

Sleep patterns over 15-day period in rats with spinal cord injury.

STUDY DESIGN: Experimental, controlled trial. OBJECTIVES: The purpose of this study was to evaluate over a 15-day period alterations in sleep pattern of rats after spinal cord injury (SCI). SETTING: Federal University of São Paulo, Department of Psychobiology. METHODS: In total, 20 male Wistar rats were used. The rats were divided in two groups: SHAM and SCI. The rats were submitted to the following procedures: electrode insertion surgery, 24 h duration baseline sleep recording, SCI (level T9) and subsequent sleep recording for 15 consecutive days. RESULTS: The results showed a reduction in sleep efficiency in the light period for Days 1-3, 5, 10 and 12 after SCI in relation to the SHAM group, with alterations in total waking time and sleep stages. Limb movements were observed 4 days after SCI. CONCLUSION: The present findings suggest that SCI may be heavily involved in altering sleep pattern in SCI subjects and that the inactivity caused by SCI may be exacerbating this altered sleep pattern.

Anesthesia↗
PubMed2006

Association of paradoxical sleep deprivation and ecstasy (MDMA) enhances genital reflexes in male rats.

Ecstasy ((+/-)3,4-methylenedioxymethamphetamine, MDMA) is a psychostimulant and a synthetic derivative of amphetamine that, according to its consumers, promotes the enhancement of sexual pleasure. This study sought to investigate the effects of ecstasy in the genital reflexes of paradoxical sleep deprived (PSD) male rats. Distinct groups of PSD rats were administered with saline or different doses of ecstasy. The incidence of genital reflexes was verified for 100 min. The four doses that were used induced genital reflexes in PSD animals and these significantly differed from their respective treated control groups. Under the influence of two intermediary doses (2.5 and 5mg/kg), all animals displayed erection and ejaculation. The frequency of genital reflexes was also significantly greater than in relation to the PSD-saline group. The comparison between cocaine and ecstasy in PSD rats revealed that ecstasy induced more erections and ejaculations than cocaine. Thus, the present results showed a great enhancement of the genital reflexes of PSD rats that might have occurred due to serotoninergic alterations induced by this illicit substance when associated to sleep deprivation.

Adrenergic Uptake Inhibitors↗
PubMed2006

Sleep disturbances, oxidative stress and cardiovascular risk parameters in postmenopausal women complaining of insomnia.

OBJECTIVE: The aim of this work was to investigate cardiovascular risk factors and oxidative stress parameters as well as sleep disturbances in polysomnography recordings of 38 postmenopausal women with insomnia. METHODS: Polysomnography recordings were performed on subjects for sleep analysis. Oxidative stress parameters were analyzed by measuring blood concentration of catalase, superoxide dismutase (SOD), thiobarbituric acid reactive substances (TBARS) and glutathione. For cardiovascular risk factors, we measured plasma levels of homocysteine, folic acid and vitamin B6. RESULTS: Findings of polysomnography recordings revealed: 68% experienced decreased sleep efficiency, 50% had apnea, 7.8% had periodic leg movements and 2.6% had bruxism (involuntary gnashing and grinding of the teeth during sleep). Our results showed that the majority of our subjects presented normal concentrations of the parameters studied according to standards reached in our laboratory. The only notable exception was TBARS. In this case, only 21% displayed normal values. We also found inverse correlations between SOD activity and both age and time of menopause. CONCLUSIONS: Although all women complained of insomnia, 50% of them demonstrated apnea during polysomnography recordings. Of the parameters measuring oxidative stress, only TBARS levels were increased in our sample. Some clinical data, such as time of onset of menopause, may be associated with the oxidative stress status of these women, probably due to the lack of estrogen and to sleep disturbances, such as apnea.

Cardiovascular Diseases↗
PubMed2006

Paradoxical sleep deprivation and sleep recovery: effects on the hypothalamic-pituitary-adrenal axis activity, energy balance and body composition of rats.

Numerous studies indicate that sleep deprivation alters energy expenditure. However, this conclusion is drawn from indirect measurements. In the present study, we investigated alterations of energy expenditure, body composition, blood glucose levels, plasma insulin, adrenocorticotropic hormone (ACTH) and corticosterone levels immediately after 4 days of sleep deprivation or after 4 days of sleep recovery. Rats were sleep deprived or maintained in a control environment (groups sleep-deprived/deprivation and control/deprivation). One half of these animals were sacrificed at the end of the deprivation period and the other half was transported to metabolic cages, where they were allowed to sleep freely (groups sleep-deprived/recovery and control/recovery). At the end of the sleep recovery period, these rats were sacrificed. After sleep deprivation, sleep-deprived rats exhibited loss of body weight, augmented energy expenditure and reduced metabolic efficiency compared to control rats. These alterations were normalised during the sleep recovery period. The body composition of sleep-deprived rats was altered insofar as there was a loss of fat content and gain of protein content in the carcass compared to control rats. However, these alterations were not reversed by sleep recovery. Finally, plasma levels of insulin were reduced during the sleep deprivation period in both control and sleep deprived groups compared to the recovery period. After the deprivation period, plasma ACTH and corticosterone levels were increased in sleep-deprived rats compared to control rats, and although ACTH levels were similar between the groups after the sleep recovery period, corticosterone levels remained elevated in sleep-deprived rats after this period. By means of direct measurements of metabolism, our results showed that sleep deprivation produces increased energy expenditure and loss of fat content. Most of the alterations were reversed by sleep recovery, except for corticosterone levels and body composition.

Adipose Tissue↗
PubMed2006

Sleep disorders, sleepiness and traffic safety: a public health menace.

Sleep disorders are not uncommon and have been widely reported throughout the world. They have a profound impact on industrialized 24-h societies. Consequences of these problems include impaired social and recreational activities, increased human errors, loss of productivity, and elevated risk of accidents. Conditions such as acute and chronic insomnia, sleep loss, excessive sleepiness, shift-work, jet lag, narcolepsy, and sleep apnea warrant public health attention, since residual sleepiness during the day may affect performance of daily activities such as driving a car. Benzodiazepine hypnotics and zopiclone promote sleep, both having residual effects the following day including sleepiness and reduced alertness. In contrast, the non-benzodiazepine hypnotics zolpidem and zaleplon have no significant next-day residual effects when taken as recommended. Research on the effects of wakefulness-promoting drugs on driving ability is limited. Countermeasures for excessive daytime sleepiness have a limited effect. There is a need for a social awareness program to educate the public about the potential consequences of various sleep disorders such as narcolepsy, sleep apnea, shift-work-related sleep loss, and excessive daytime sleepiness in order to reduce the number of sleep-related traffic accidents.

Accidents, Traffic↗
PubMed2006

Repercussions of a sleep medicine outreach program.

Despite the high prevalence of sleep disorders, many healthcare professionals and lay people have little knowledge of Sleep Medicine. Mindful of such a reality, in 2001 the Sleep Institute of the Associação Fundo de Incentivo à Psicofarmacologia launched a campaign to increase Sleep Medicine awareness. Media features, exhibitions, inserts, and classes were used to reach 2,000,000 people and 55,000 healthcare professionals during the period from 2001 to 2004. To evaluate this program, we compared data for polysomnography referrals to the Institute in 2000 and in 2004. A total of 8805 referrals were evaluated (2000: 2164; 2004: 6641). Over the 4 years of the program, the number of beds increased by 43%; more women were referred (31 vs 37%; P < 0.001), mainly with a diagnostic hypothesis of sleep-disorder breathing (SDB). SDB was the most frequent diagnostic hypothesis in 2000 and 2004. In 2004 there were fewer referrals without a diagnostic hypothesis (27 vs 21%; P < 0.001) and for controlling surgically treated SDB (2.3 vs 1.6%; P < 0.05), and an increase in the following diagnostic hypotheses: non-invasive treatment of SDB (8.3 vs 12.3%; P < 0.001) and insomnia (3.5 vs 6.5%; P < 0.001). Insomnia diagnostic hypothesis was better correlated with SDB on referral documents in 2004 and less with a diagnostic hypothesis of limb movement disturbance. The program helped increase polysomnography referrals, particularly among women. Healthcare professionals appear to have a more developed understanding of sleep disorders.

Brazil↗
PubMed2006

Obese obstructive sleep apnea patients with tonsil hypertrophy submitted to tonsillectomy.

The physiopathology of obstructive sleep apnea-hypopnea syndrome (OSAHS) is multifactorial and obesity has been shown to be one of the main factors correlated with its occurrence. In obese patients with anatomical alterations of the upper airways it is often difficult to predict success for surgical correction since obesity is a limiting factor. Therefore, the aim of the present study was to evaluate the results of tonsillectomy in a specific group of patients, i.e., obese OSAHS patients with tonsil hypertrophy. Seven OSAHS patients with moderate obesity with obstructive palatine tonsil hypertrophy were submitted to tonsillectomy. All patients were submitted to pre- and postoperative appraisal of body mass index, otorhinolaryngology examination and polysomnography. Patients' average age was 36.4 +/- 10.3 years and average preoperative body mass index was 36.6 +/- 6.3 kg/m(2). Postoperative weight did not differ significantly from preoperative weight (P = 0.27). Average preoperative apnea and hypopnea index (AHI) was 81 +/- 26/h and postoperative AHI was 23 +/- 18/h (P = 0.0005). Average preoperative minimum oxyhemoglobin saturation (SaO2 min) was 69 +/- 14% and the postoperative value was 83 +/- 3% (P = 0.038). In relation to AHI, 6 (86%) of the 7 patients studied showed a reduction of 50% in relation to preoperative level and of these, 4 (57%) presented AHI of less than 20%. Only one patient presented a reduction of less than 50% in AHI, but even so showed improved SaO2 min. Tonsillectomy treatment for OSAHS in obese patients with obstructive palatine tonsil hypertrophy caused a significant reduction in AHI, with improvement in SaO2 min. This procedure could be eventually considered as an option of treatment for obese OSAHS patients with significant tonsil hypertrophy when continuous positive air pressure therapy is not possible as the first choice of treatment.

Adult↗
PubMed2006

Effects of progesterone on sleep: a possible pharmacological treatment for sleep-breathing disorders?

Progesterone is present in a wide spectrum of biological activity within a variety of tissues. This hormone is also known to affect reproduction, sleep quality, respiration, mood, appetite, learning, memory and sexual activity. Progesterone exerts a sleep induction or hypnotic effect and is a potent respiratory stimulant that has been associated to a decrease in the number of central and obstructive sleep apnea episodes in men. The literature also contains a substantial amount of data on the effect of apnea in women with obesity-hypoventilation during menopause. This review attempts to outline the specific role of progesterone in normal sleep and breathing as well as its possible therapeutic effects in the treatment of sleep-disordered breathing.

Female↗
PubMed2005

Effects of type of physical exercise and leisure activities on the depression scores of obese Brazilian adolescent girls.

Several studies have indicated that depressive states may lead to hypokinesia with diminished metabolic rate and energy use. Hypokinesia associated with certain eating behaviors may lead to an unfavorable energy balance that can contribute to the emergence and prevalence of obesity among children and adults. The purpose of the present study was to examine the possibility of reducing depression inventory scores in female adolescents with third-degree obesity while testing the effectiveness of different exercise programs in reducing anxiety and depression scores. The sample consisted of 40 female subjects (mean age 16 +/- 1.56 years) divided into 4 groups (aerobic training, anaerobic training, leisure activities, and control). Subjects had a body mass index of 95% or more in relation to the 50th percentile. The aerobic program consisted of three ergometric bicycle sessions per week over a 3-month period (12 weeks) and the activities were prescribed after determining the anaerobic ventilatory threshold (VO2 threshold). Anaerobic training was based on the Wingate anaerobic power test. The leisure program consisted of a varied range of activities (games, exercises, etc.). A nutritionist interviewed the members of these two groups and the control group every week in order to adapt them to the nutritional guidelines proposed for the study. The study showed that all three programs (aerobic exercise, anaerobic exercise and leisure activities) were effective in reducing body mass. However, we found a significant reduction when analyzing the depression scores only for aerobic exercise (18.9 +/- 9.33 to 10.6 +/- 9.56 or 43.9%) but no significant alterations for anaerobic exercise (11.36 +/- 5.23 to 9.63 +/- 4.78 or 15.22%) and leisure (17.28 +/- 7.55 to 15.07 +/- 7.54 or 12.78%), thus indicating that in principle this type of activity could be included to improve emotional well-being of obese adolescent girls.

Adolescent↗
PubMed2005

Sleep pattern in rats under different stress modalities.

The present study was designed to evaluate the sleep pattern of rats submitted to chronic stressors (restraint, electrical footshock, swimming and cold) applied to male rats. After 48 h-baseline recording, rats were submitted to 4 days of chronic stress, and electrocorticogram recordings were carried out continuously. The stressors (footshock, swimming and cold) were applied twice a day for periods of 1 h at 9:00 and 16:00 h. Restrained animals were maintained in plastic cylinders for 22 h/day. The findings indicated that sleep efficiency, slow wave sleep (SWS) and paradoxical sleep (PS) were decreased on the third and fourth days of unpredictable shocks compared to baseline while immobilization and swimming presented reduced sleep efficiency in all 4-day recordings. Swimming led to decreased SWS, whereas augmented PS was observed on the first day compared to baseline. Immobilization produced drastic alterations in sleep patterns since it reduced SWS during the 4 days and PS at days 1 to 4 in relation to baseline. Of all stressors, cold was the only one that did not result in any statistical differences in sleep pattern during the light periods. Regarding the effect of stress compared to baseline on the dark recordings, PS was higher during cold stress periods, whereas footshock increased PS on days 2 to 4 and swimming only on day 2. Immobilization decreased PS throughout the 4 days of the stress sessions. Thus, the data suggest that different stress modalities result in distinct sleep responses, with immobilization producing the most dramatic alterations.

Animals↗
PubMed2005

Functional specializations within the tectum defense systems of the rat.

Here we review the differential contribution of the periaqueductal gray matter (PAG) and superior colliculus (SC) to the generation of rat defensive behaviors. The results of studies involving sine-wave and rectangular pulse electrical stimulation and chemical (NMDA) stimulation are summarized. Stimulation of SC and PAG produced freezing and flight behaviors along with exophthalmus (fully opened bulged eyes), micturition and defecation. The columnar organization of the PAG was evident in the results obtained. Defecation was elicited primarily by lateral PAG stimulation, while the remaining defensive behaviors were similarly elicited by lateral and dorsolateral PAG stimulation, although with the lowest thresholds in the dorsolateral column. Conversely, the ventrolateral PAG did not appear to participate in unconditioned defensive behaviors, which were only elicited by high intensity stimulation likely to encroach on adjacent regions. In the SC, the most important differences relative to the PAG were the lack of stimulation-evoked jumping in both intermediate and deep layers, and of NMDA-evoked galloping in intermediate layers. Therefore, we conclude that the SC may be only involved in the increased attentiveness (exophthalmus, immobility) and restlessness (trotting) of prey species exposed to the cues of a nearby predator. These responses may be distinct from the full-blown flight reaction that is mediated by the dorsolateral and lateral PAG. However, other evidences suggest the possible influences of stimulation schedule, environment dimensions and rat strain in determining outcomes. Overall our results suggest a dynamically organized representation of defensive behaviors in the midbrain tectum.

Animals↗
PubMed2005

Organization of electrically and chemically evoked defensive behaviors within the deeper collicular layers as compared to the periaqueductal gray matter of the rat.

Stimulation of the periaqueductal gray matter (PAG) and the deeper layers of superior colliculus (SC) produces both freezing (tense immobility) and flight (trotting, galloping and jumping) behaviors along with exophthalmus (fully opened bulging eyes) and, less often, micturition and defecation. The topography of these behaviors within the distinct layers of SC remains unclear. Therefore, this study compared the defensive repertoire of intermediate (ILSC) and deep (DLSC) layers of SC to those of dorsolateral periaqueductal gray matter (DLPAG) and lateral periaqueductal gray matter (LPAG) [Neuroscience 125 (2004) 71]. Electrical stimulation was carried out through intensity- (0-70 microA) and frequency-varying (0-130 Hz) pulses. Chemical stimulation employed a slow microinfusion of N-methyl-d-aspartic acid (NMDA, 0-2.3 nmol, 0.5 nmol/min). Probability curves of intensity-, frequency- and NMDA-evoked behaviors, as well as the unbiased estimates of median stimuli, were obtained by threshold logistic analysis. Compared with the PAG, the most important differences were the lack of frequency-evoked jumping in both layers of SC and the lack of NMDA-evoked galloping in the ILSC. Moreover, although galloping and jumping were also elicited by NMDA stimulation of DLSC, effective doses were about three times higher than those of DLPAG, suggesting the spreading of the injectate to the latter structure. In contrast, exophthalmus, immobility and trotting were evoked throughout the tectum structures. However, whatever the response and kind of stimulus, the lowest thresholds were always found in the DLPAG and the highest ones in the ILSC. Besides, neither the appetitive, nor the offensive, muricide or male reproductive behaviors were produced by any kind of stimulus in the presence of appropriate targets. Accordingly, the present data suggest that the deeper layers of SC are most likely involved in the increased attentiveness (exophthalmus, immobility) or restlessness (trotting) behaviors that herald a full-blown flight reaction (galloping, jumping) mediated in the PAG.

Aggression↗
PubMed2004

Different stress modalities result in distinct steroid hormone responses by male rats.

Since both paradoxical sleep deprivation (PSD) and stress alter male reproductive function, the purpose of the present study was to examine the influence of PSD and other stressors (restraint, electrical footshock, cold and forced swimming, N = 10 per group) on steroid hormones in adult Wistar male rats. Rats were submitted to chronic stress for four days. The stressors (footshock, cold and forced swimming) were applied twice a day, for periods of 1 h at 9:00 and 16:00 h. Restrained animals were maintained in plastic cylinders for 22 h/day whereas PSD was continuous. Hormone determination was measured by chemiluminescent enzyme immunoassay (testosterone), competitive immunoassay (progesterone) and by radioimmunoassay (corticosterone, estradiol, estrone). The findings indicate that PSD (13.7 ng/dl), footshock (31.7 ng/dl) and cold (35.2 ng/dl) led to lower testosterone levels compared to the swimming (370.4 ng/dl) and control (371.4 ng/dl) groups. However, progesterone levels were elevated in the footshock (4.5 ng/ml) and PSD (5.4 ng/ml) groups compared to control (1.6 ng/ml), swimming (1.1 ng/ml), cold (2.3 ng/ml), and restrained (1.2 ng/ml) animals. Estrone and estradiol levels were reduced in the PSD, footshock and restraint groups compared to the control, swimming and cold groups. A significant increase in corticosterone levels was found only in the PSD (299.8 ng/ml) and footshock (169.6 ng/ml) groups. These changes may be thought to be the full steroidal response to stress of significant intensity. Thus, the data suggest that different stress modalities result in distinct steroid hormone responses, with PSD and footshock being the most similar.

Animals↗
PubMed2004

Zolpidem and memory: a study using the process-dissociation procedure.

RATIONALE: There is a dearth of studies which have employed sophisticated paradigms to investigate the effects of zolpidem on memory. OBJECTIVES: To explore anterograde cognitive deficits induced by acute oral doses of zolpidem by means of the process-dissociation procedure (PDP). METHODS: The present study followed a placebo-controlled, double-blind, parallel-group design. Young, healthy females were randomly allocated to one of three treatments with 12 subjects each: placebo, 5 mg and 10 mg zolpidem. Two word-stem completion tasks were carried out close to theoretical peak-plasma concentration: a) direct inclusion task with cued recall, in which participants had to try to use words seen at study to complete stems; and b) direct exclusion task, in which words seen at study were to be avoided as completions. The PDP was applied to the results in these tasks to yield indices of explicit/controlled (C) and implicit/automatic (A) memory. Classical psychometric tests were also carried out. RESULTS: Zolpidem 10 mg led to cognitive effects similar to benzodiazepines (except for the atypical lorazepam), including impairment of exclusion, but not inclusion-task performance. Results of the application of the PDP were inconclusive but concurred with the pattern established in previously published work on benzodiazepine effects, i.e. that zolpidem (10 mg) impaired C. CONCLUSIONS: Zolpidem leads to cognitive effects similar to most benzodiazepines. Although the application of PDP in drug studies may be counterproductive in view of methodological difficulties that are discussed, the pattern of effects on the stem-completion tasks involved in this paradigm is potentially useful in the investigation of cognitive effects of psychoactive drugs.

Administration, Oral↗
PubMed2004

Effects of paradoxical sleep deprivation on blood parameters associated with cardiovascular risk in aged rats.

The effects of 96 h of paradoxical sleep deprivation (PSD) on blood parameters associated with cardiovascular risk were studied in young (3-month old) and aged (22-month old) rats. In general, aging was associated with an overall increase in most measures, irrespective of sleep deprivation condition. The latter manipulation also had significant effects on blood variables, but not in a consistent pattern. Thus, PSD significantly reduced triglyceride levels in both young and aged rats; it reduced blood viscosity in aged but not in young rats, and had no effect on the increased cholesterol levels observed in aged controls. Examinations of cholesterol fractions revealed significant increases in low density lipoprotein and high density lipoprotein in aged PSD rats compared to respective controls, whereas very low density lipoprotein was significant decreased after PSD in both young and aged animals. PSD increased vitamin B(12) levels in aged rats, and significantly decreased homocysteine levels in young but not in aged rats which in turn were already reduced. Folate levels were the only variable that was unaffected by aging and/or PSD. These results indicate that PSD has significant but heterogeneous physiological effects in aged rats and may intensify certain aging-related effects which contribute to cardiovascular disease risk while attenuating others.

Age Factors↗