Autonomic activity during human sleep as a function of time and sleep stage

While there is a developing understanding of the influence of sleep on cardiovascular autonomic activity in humans, there remain unresolved issues. In particular, the effect of time within the sleep period, independent of sleep stage, has not been investigated. Further, the influence of sleep on central sympathetic nervous system (SNS) activity is uncertain because results using the major method applicable to humans, the low frequency (LF) component of heart rate variability (HRV), have been contradictory, and because the method itself is open to criticism. Sleep and cardiac activity were measured in 14 young healthy subjects on three nights. Data was analysed in 2-min epochs. All epochs meeting specified criteria were identified, beginning 2 h before, until 7 h after, sleep onset. Epoch values were allocated to 30-min bins and during sleep were also classified into stage 2, slow wave sleep (SWS) and rapid eye movement (REM) sleep. The measures of cardiac activity were heart rate (HR), blood pressure (BP), high frequency (HF) and LF components of HRV and pre-ejection period (PEP). During non-rapid eye movement (NREM) sleep autonomic balance shifted from sympathetic to parasympathetic dominance, although this appeared to be more because of a shift in parasympathetic nervous system (PNS) activity. Autonomic balance during REM was in general similar to wakefulness. For BP and the HF and LF components the change occurred abruptly at sleep onset and was then constant over time within each stage of sleep, indicating that any change in autonomic balance over the sleep period is a consequence of the changing distribution of sleep stages. Two variables, HR and PEP, did show time effects reflecting a circadian influence over HR and perhaps time asleep affecting PEP. While both the LF component and PEP showed changes consistent with reduced sympathetic tone during sleep, their pattern of change over time differed.

Sub-chronic impact of cannabinoids in street cannabis on cognition, psychotic-like symptoms and psychological well-being

BACKGROUND

Cannabis varies considerably in levels of its two major constituent cannabinoids - (delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Recently, we found evidence that those who smoked cannabis containing detectable levels of CBD had fewer psychotic-like symptoms than those whose cannabis had no CBD. The present study aimed, first, to replicate those findings and, second, to determine whether protective effects of CBD may extend to other harms of cannabis, such as memory impairment and reduced psychological well-being.

METHOD

A total of 120 current cannabis smokers, 66 daily users and 54 recreational users were classified into groups according to whether analysis of their hair revealed the presence or absence of CBD and high versus low levels of THC. All were assessed on measures of psychosis-like symptoms, memory (prose recall; source memory) and depression/anxiety.

RESULTS

Lower psychosis-like symptoms were found in those whose hair had CBD compared with those without. However, this was seen only in recreational users, who had higher levels of THC in their hair. Higher THC levels in hair were associated with increased depression and anxiety. Prose recall and source memory were poorer in daily users with high THC levels in hair while recognition memory was better in individuals with CBD present in hair.

CONCLUSIONS

CBD attenuates the psychotic-like effects of cannabis over time in recreational users. Higher THC negatively impacts on memory and psychological well-being. These findings raise concerns for the harms stemming from use of varieties such as 'skunk' (sensimillia), which lack any CBD but currently dominate the supply of cannabis in many countries.

Mild prenatal stress enhances learning performance in the non-adopted rat offspring

The present study was designed to investigate whether mild stress during pregnancy affects offspring behaviors, including learning performance. Prenatal stress was induced by short-lasting, mild restraint stress, which had previously been shown to facilitate the morphological development of fetal brain neurons. Adult offspring whose dams had been restrained in a small cage for 30min daily from gestation day 15 to 17 showed enhanced active avoidance and radial maze learning performance. In addition, the prenatally stressed rats showed weaker emotional responses than unstressed control, as indicated by decreases both in ambulation upon initial exposure to an open field and in Fos expression in the amygdala induced by physical stress. The observed effects of prenatal stress on learning performance and emotional behavior were attenuated by foster rearing by unstressed dams. Fos expression in the hypothalamic paraventricular nucleus following physical stress and corticosterone secretion during physical and psychological stress did not differ between the prenatally stressed and unstressed control rats. From these results we suggest that mild prenatal stress facilitates learning performance in the adult offspring. The enhancement of learning performance appears to be accompanied by reduced emotionality, but not by any apparent alterations in hypothalamic-pituitary-adrenal responses. In addition, the observation of differential behaviors in the adopted and non-adopted animals supports the notion that the postnatal environment modifies the behavioral effects of prenatal stress.

Hepatocyte transplantation followed by auxiliary liver transplantation--a novel treatment for ornithine transcarbamylase deficiency

We report the first successful use of hepatocyte transplantation as a bridge to subsequent auxiliary partial orthotopic liver transplantation (APOLT) in a child antenatally diagnosed with severe ornithine transcarbamylase (OTC) deficiency. A total of 1.74 x 10(9) fresh and cryopreserved hepatocytes were administered intraportally into the liver over a period of 6 months. Immunosuppression was with tacrolimus and prednisolone. A sustained decrease in ammonia levels and a gradual increase in serum urea were observed except during episodes of sepsis in the first 6 months of life. The patient was able to tolerate a normal protein intake and presented a normal growth and neurological development. APOLT was successfully performed at 7 months of age. We conclude that hepatocyte transplantation can be used in conjunction with APOLT as an effective treatment for severe OTC-deficient patients, improving neurodevelopmental outcomes.

The central role of corticotrophin-releasing factor (CRF-41) in psychological stress in rats

1. We investigated the central role of corticotrophin-releasing factor (CRF-41) in psychological stress-induced responses, including cardiovascular, thermoregulatory and locomotive activity in free-moving rats. 2. Psychological stress was induced by cage-switch stress. After rats were placed in the novel environment, blood pressure, heart rate, body temperature and locomotive activity significantly increased. The intracerebroventricular (I.C.V.) injection of alpha-helical CRF(9-41), a CRF-41 receptor antagonist, significantly attenuated the stress-induced hypertension, tachycardia, hyperthermia and increase in locomotive activity. However, in unstressed rats, the I.C.V. injection of alpha-helical CRF(9-41) had no effect on physiological parameters measured in this study. 3. In unstressed rats, the I.C.V. injection of CRF-41 (1 microgram and 10 micrograms) increased blood pressure, heart rate, body temperature and locomotive activity in a dose-dependent manner. The changes in these responses were quite similar to those observed during cage-switch stress. 4. The results suggest that central CRF-41 plays an important role in psychological stress-induced hypertension, hyperthermia, tachycardia and increase in locomotive activity. However, it is likely that central CRF-41 does not contribute to normal cardiovascular and body temperature regulation when rats are free from stress.

Enhancement of parasympathetic cardiac activity during activation of muscle metaboreflex in humans

We measured the changes in heart rate (HR) variability estimated from the standard deviation of the R-R intervals to evaluate cardiac parasympathetic tone noninvasively before and during activation of muscle metaboreflex induced by postexercise muscle ischemia. Eight healthy male subjects performed sustained handgrip at 50% maximal voluntary contraction followed by forearm occlusion. Mean arterial pressure, cardiac stroke volume, and ratio of cardiac preejection period to left ventricular ejection time (PEP/LVET) were also measured. During the 2-min occlusion after 60 s of handgrip with voluntary respiration, HR variability and mean arterial pressure were significantly increased from baseline (54.4 +/- 6.1 to 80.1 +/- 12.8 ms and 81 +/- 1 to 99 +/- 3 mmHg, respectively) and PEP/LVET was decreased from resting level of 0.404 +/- 0.022 to 0.363 +/- 0.036. During occlusion and recovery, HR did not change from baseline level in any experiment. There was no influence of occlusion itself or of cessation of exercise per se on any parameters. Although overall enhanced HR variability was seen, probably due to lower breathing frequency and larger tidal volume, similar results were also obtained from an experiment with controlled respiration, showing that the increase in HR variability was not due to the changes in tidal volume or breathing frequency during occlusion. In conclusion, the HR variability is increased during activation of the muscle metaboreflex induced by postexercise muscle ischemia in humans. This finding shows that the parasympathetic cardiac tone is enhanced during activation of the muscle metaboreflex in humans and balances enhanced cardiac sympathetic activity to result in an unchanged HR.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct Septum-Hippocampus Cholinergic Circuit Attenuates Seizure Through Driving Somatostatin Inhibition

BACKGROUND

Previous studies indicated the involvement of cholinergic neurons in seizure; however, the specific role of the medial septum (MS)-hippocampus cholinergic circuit in temporal lobe epilepsy (TLE) has not yet been completely elucidated.

METHODS

In the current study, we used magnetic resonance imaging and diffusion tensor imaging to characterize the pathological change of the MS-hippocampus circuit in 42 patients with TLE compared with 22 healthy volunteers. Using optogenetics and chemogenetics, combined with in vivo or in vitro electrophysiology and retrograde rabies virus tracing, we revealed a direct MS-hippocampus cholinergic circuit that potently attenuates seizure through driving somatostatin inhibition in animal TLE models.

RESULTS

We found that patients with TLE with hippocampal sclerosis showed a decrease of neuronal fiber connectivity of the MS-hippocampus compared with healthy people. In the mouse TLE model, MS cholinergic neurons ceased firing during hippocampal seizures. Optogenetic and chemogenetic activation of MS cholinergic neurons (but not glutamatergic or GABAergic [gamma-aminobutyric acidergic] neurons) significantly attenuated hippocampal seizures, while specific inhibition promoted hippocampal seizures. Electrophysiology combined with modified rabies virus tracing studies showed that direct (but not indirect) MS-hippocampal cholinergic projections mediated the antiseizure effect by preferentially targeting hippocampal GABAergic neurons. Furthermore, chemogenetic inhibition of hippocampal somatostatin-positive (rather than parvalbumin-positive) subtype of GABAergic neurons reversed the antiseizure effect of the MS-hippocampus cholinergic circuit, which was mimicked by activating somatostatin-positive neurons.

CONCLUSIONS

These findings underscore the notable antiseizure role of the direct cholinergic MS-hippocampus circuit in TLE through driving the downstream somatostatin effector. This may provide a better understanding of the changes of the seizure circuit and the precise spatiotemporal control of epilepsy.

Sympatho-adrenal involvement in methamphetamine-induced hyperthermia through skeletal muscle hypermetabolism

We investigated the involvement of the sympatho-adrenal axis in the hyperthermia induced by methamphetamine by using a biotelemetric system. The intraperitoneal injection of methamphetamine (1 mg/kg) induced hyperthermia preceded by an increase in oxygen consumption in freely moving rats. The hyperthermic effect of methamphetamine was completely blocked by chemical sympathectomy with 6-hydroxydopamine (50 mg/kg, i.p.). Adrenalectomy, but not adrenal demedullation, prevented the hyperthermia. In adrenalectomized rats, dexamethasone supplementation (0.5 mg/kg, s.c.) restored the methamphetamine-induced hyperthermia. Furthermore, dantrolene (1 or 2 mg/kg, i.v.), which blocks Ca2+ release from the sarcoplasmic reticulum in skeletal muscle, attenuated the hyperthermia. These results suggest that methamphetamine stimulates norepinephrine release from sympathetic nerve terminals, which then enhances thermogenesis in skeletal muscle under the permissive action of glucocorticoids.

Safety and efficacy of the modified peroral endoscopic myotomy with shorter myotomy for achalasia patients: a prospective study

Peroral endoscopic myotomy (POEM) has been developed as a minimally invasive endoscopic treatment for achalasia for years. However, the optimal length of submucosal tunnel and myotomy of muscle bundles during procedure of POEM has not yet been determined, so we aim to assess safety and efficacy of modified POEM with shorter myotomy of muscle bundles in achalasia patients. Consecutive achalasia patients had been performed modified POEM with shorter myotomy, and assessed by symptoms, high-resolution manometry, and barium swallow examinations before and 3 months after POEM for safety and efficacy evaluation. Modified POEM with shorter submucosal tunnel (mean length 6.8 cm) and endoscopic myotomy of muscle bundles (total mean length 5.4 cm) were completed in 46 consecutive achalasia patients. During the 3-month follow up in all cases, significant improvement of symptoms (a significant drop in the Eckardt score 8.4 ± 3.2 vs. 2.7 ± 1.9; P < 0.001), decreased lower esophageal sphincter pressure (39.4 ± 10.1 vs. 24.4 ± 9.1 mmHg; P < 0.001) and integrated relaxation pressure (38.6 ± 10.4 vs. 25.7 ± 9.6 mmHg; P < 0.01), and a drop in height of esophagus barium-contrast column (5.4 ± 3.1 vs. 2.6 ± 1.8 cm; P < 0.001) were observed. The frequencies of adverse events were lower in those under endotracheal anesthesia and CO2 insufflations compared with intravenous anesthesia and air insufflations. Only three patients were found to have gastroesophageal reflux disease on follow up. Modified POEM with shorter myotomy under endotracheal anesthesia and CO2 insufflations shows its good safety and excellent short-term efficacy in the treatment of achalasia. But further studies are warranted to assess the long-term efficacy.

Biosorption of uranium(VI) by a mangrove endophytic fungus Fusarium sp. #ZZF51 from the South China Sea

The uranium(VI) accumulation was studied in detail by using the biomass of mangrove endophytic fungus Fusarium sp.#ZZF51 from the South China Sea. The uranium(VI) biosorption process onto the tested fungus powders was optimized at pH 4.0, adsorption time 60 min, and uranium(VI) initial concentration 50 mg L⁻¹ with 61.89% of removal efficiency. According to Fourier transform infrared spectra for the tested fungus before and after loaded with uranium(VI), the results showed that both of hydroxyl and carboxyl groups acted as the important roles in the adsorption process. In addition, the experimental data were analyzed by using parameter and kinetic models, and it was obtained that the Langmuir isotherm model and the pseudo-second-order kinetic model provided better correlation with the experimental data for adsorption of uranium(VI).

Modulating effects of prenatal stress on hyperthermia induced in adult rat offspring by restraint or LPS-induced stress

The present study was carried out to investigate the effects of prenatal stress on stress-induced hyperthermia in adult rats. Prenatal stress was administered daily for 3 days (embryonic days 15-17) by restraining pregnant rats in a small cage either for 30 or 240 min. After birth, foster mothers raised the pups. Offspring were tested at 9-10-weeks-old. Changes in body temperature and in the plasma concentrations of corticosterone, norepinephrine (NE), and epinephrine (Epi) induced by restraint or lipopolysaccharide (LPS)-induced stress were examined. By comparison with the prenatally nonstressed control group, the 240-min stress group showed a significantly lower hyperthermia in response to restraint stress but a higher fever after injection of LPS. The 30-min stress group showed similar alterations in these hyperthermic responses but did not reach significance. Both the restraint stress and the injection of LPS evoked greater increases in the plasma level of corticosterone in the 240-min stress group than in the control group. Although restraint stress induced significant increases in NE and Epi in the control and 30-min stress groups, the plasma levels of these catecholamines did not increase in the 240-min stress group. These results demonstrate for the first time that prenatal stress has opposite effects on the hyperthermic responses to restraint and LPS injection, suggesting that different mechanisms underlie the modulating effects of prenatal stress on the responses to the two types of stressors.

Relationship between mean arterial pressure and muscle cell pH during forearm ischaemia after sustained handgrip

Recent evidence suggests that there is a close correlation between the physiological responses to muscle chemoreflex and the decrease in intracellular pH during ischaemia after handgrip. This study evaluated whether the relationship is linear or has an apparent threshold. We measured muscle cellular pH through phosphorous nuclear magnetic resonance spectroscopy (31P-NMR), mean arterial blood pressure (MAP) and heart rate (HR) during ischaemia after sustained handgrip exercise at 50% of maximum voluntary contraction (MVC). Contraction was sustained for 15, 30, 45 and 60 s, followed by 2 min of circulatory arrest, respectively. Muscular pH during the ischaemia decreased linearly with increasing contraction time, from the base-line level of 7.11 +/- 0.03 units (U) to 6.98 +/- 0.03, 6.90 +/- 0.04, 6.72 +/- 0.06 and 6.54 +/- 0.06 U after 15-, 30, 45-, and 60-s contractions, respectively. The MAP was 86 +/- 2 mmHg at rest and did not change during the ischaemia after 15- and 30-s contractions. However, it significantly increased to 95 +/- 2 and 107 +/- 2 mmHg, after 45- and 60-s contractions, respectively. These data indicate that the relationship between MAP and pH is not a single linear relationship, showing one breaking point around the pH of 6.90 units. It suggests that the muscle chemoreflex has a clear threshold around 6.90 units of muscle pH, and below this pH, MAP increased linearly with decreasing muscle cellular pH.

Cardiovascular and humoral responses to sustained muscle metaboreflex activation in humans

The cardiovascular and humoral responses to sustained muscle metaboreflex activation were examined in eight male volunteers while they performed two 24-min exercise protocols. Each of these consisted of six 1-min bouts of isometric handgrip exercise (the left and right hands being used alternately) at 50% of maximal voluntary contraction; after each bout, there was either 3-min postexercise occlusion (occlusion protocol) or 3-min rest (control protocol). In the occlusion protocol, mean arterial blood pressure was approximately 25 mmHg higher than during the control protocol, indicating that the muscle metaboreflex was activated during occlusion. During the control protocol, plasma renin activity, plasma vasopressin, and adrenocorticotropic hormone values were not significantly different from the values at rest. During the occlusion protocol, however, plasma renin activity, plasma vasopressin, and adrenocorticotropic hormone were all significantly increased at 25 min. These data demonstrate that, in humans, the sustained activation of the muscle metaboreflex causes the secretion of several hormones originating from different regions.

Biological activities of a Turkish medicinal plant, Prangos platychlaena

Prangos platychlaena has been used in traditional medicine in eastern Turkey. It stops bleeding and heals the scars when applied externally. When the isolated coumarins were tested against bacterial strains, only a slight activity was obtained.

Cardiovascular responses induced in free-moving rats by immune cytokines

1. We investigated the effect of intraperitoneal (I.P.) injections of the immune cytokines, interleukin-1 beta (IL-1 beta) and tumour necrosis factor (TNF) on cardiovascular responses in free-moving rats, using a biotelemetry system. 2. The I.P. injection of a small dose of IL-1 beta (1 microgram/kg) induced a monophasic increase in the heart rate, and that of a large dose (10 micrograms/kg) induced biphasic increases in the blood pressure and heart rate. However, the I.P. injection of any of several doses of TNF (1, 10 and 50 micrograms/kg) had no effect on cardiovascular responses in rats. 3. Pre-treatment with I.P. injection of indomethacin (10 mg/kg), an inhibitor of cyclo-oxygenase, significantly suppressed the cardiovascular responses and the increase in the plasma noradrenaline (NA) concentration induced by I.P. injection of IL-1 beta. 4. Microinjection of IL-1 beta (1 and 10 ng) into the preoptic and anterior hypothalamic (PO-AH) region induced dose-dependent increases in the blood pressure and heart rate in rats. These responses were also suppressed by pretreatment with I.P. indomethacin (10 mg/kg). In addition, microinjection of prostaglandin E2 (20 and 100 ng) into the PO-AH region increased blood pressure and heart rate, but that of prostaglandin D2 (100 ng) had no effect. 5. The present results suggest that IL-1 beta stimulates the release of prostaglandins, presumably E series, near regions of the hypothalamus, which act on the hypothalamus to induce activation of the sympathetic nervous system. Subsequently, the blood pressure, heart rate and the plasma level of NA increase.

Incidence and survival characteristics of retinoblastoma in Singapore from 1968-1995

PURPOSE

To describe the incidence and survival of 69 Singapore residents with retinoblastoma in all Singapore hospitals from 1968-1995.

METHODS

Data of all Singapore residents diagnosed with retinoblastoma from 1968-1995 were collected by the Singapore Cancer Registry based on notifications from physicians, pathology records, hospital discharge records, and death certificates. The medical records of 46 patients were traced, and information on laterality of tumor, spread of tumor, mode of treatment, and family history of retinoblastoma was obtained. Time trends and survival characteristics of the cohort were described.

RESULTS

The incidence rate of retinoblastoma was 2.4 per 1 million for children <9 years and 11.1 per 1 million for children <5 years. The incidence of retinoblastoma has been almost uniform over time from 1968-1995, except for an apparent increase in 1988-1992. The 3-year survival rate for retinoblastoma was 83%. Survival rates were higher in children <2 years because children who present at a younger age may have tumors diagnosed at earlier stages of the disease. There was no difference in survival rates for sex, race, laterality, family history of retinoblastoma, treatment, or year of diagnosis.

CONCLUSION

Retinoblastoma is the most common eye cancer in children that may cause blindness or death. The incidence rates of retinoblastoma in Singapore have remained fairly stable over 28 years, and the survival rate is higher in younger children. This study will be helpful in monitoring future disease patterns in Asian populations.

Spontaneous wheel running attenuates cardiovascular responses to stress in rats

We investigated the effect of chronic, 10-week spontaneous wheel running (SWR) exercise on stress-induced cardiovascular responses in free-moving male rats, using a biotelemetry system. During cage-switch stress or immobilization stress, blood pressure and heart rate were significantly increased in both the SWR (P<0.001 for each stress) and control groups (P<0.001 for each stress). However the blood pressure response was attenuated significantly in the SWR group (P<0.001) during cage-switch stress, and the blood pressure and heart rate responses were attenuated significantly in the SWR group (P<0.0001 and 0.01, respectively) during immobilization stress. The plasma norepinephrine (NE) response induced by immobilization stress tended to be attenuated in the SWR group, but the groups showed no significant differences in the plasma NE and epinephrine (E) responses to both stresses. These results suggest that daily SWR in rats has beneficial effects in suppressing excessive blood pressure and heart rate responses induced by two different types of stress. The mechanisms responsible for the greater resistance to these stresses in the SWR rats should be investigated further.

Menkes' disease and swayback. A comparative study of two copper deficiency syndromes

The neuropathological findings in two siblings with Menkes' disease were compared with representative material obtained from lambs suffering from swayback (enzootic ataxia). The aim of the study was to demonstrate the similarity of lesions in a genetic and a nutritional form of copper deficiency in support of the view that all lesions in Menkes' disease could be ascribed to simple hypocupraemia. All lesions of Menkes' disease were shown to have their counterpart in swayback, with exception of the abnormal arborisations of the Purkinje cell dendrites. These have often been interpreted as malformations and cited in evidence of the prenatal origin of the cerebral lesions. They are, however, non-specific and similar lesions have been reported in conditions arising in later life. While there is abundant collateral evidence of disturbed copper metabolism in utero, the problem of the prenatal versus postnatal origin of cerebral damage remains unresolved.

Protein markers for Alzheimer disease in the frontal cortex and cerebellum

OBJECTIVE

To compare proteins related to Alzheimer disease (AD) in the frontal cortex and cerebellum of subjects with early-onset AD (EOAD) with or without presenilin 1 (PS1) mutations with sporadic late-onset AD (LOAD) and nondemented control subjects.

METHODS

Immunohistochemistry, immunoblot analysis, and ELISA were used to detect and assess protein levels in brain.

RESULTS

In EOAD and to a lesser extent in LOAD, there was increased amyloid beta (Abeta) deposition (by immunohistochemistry), increased soluble Abeta (by immunoblot analysis), and specific increases in Abeta40 and Abeta42 (by ELISA) in the frontal cortex and, in some cases, in the cerebellum. Surprisingly, immunoblot analysis revealed reduced levels of PS1 in many of the subjects with EOAD with or without PS1 mutations. In those PS1 mutation-bearing subjects with the highest Abeta, PS1 was barely, if at all, detectable. This decrease in PS1 was specific and not attributable solely to neuronal loss because amyloid precursor protein (APP) and the PS1-interacting protein beta-catenin levels were unchanged.

CONCLUSIONS

This study shows that in the frontal cortex and cerebellum from Alzheimer disease patients harboring certain presenilin 1 mutations, high levels of amyloid beta are associated with low levels of presenilin 1. The study provides the premise for further investigation of mechanisms underlying the downregulation of presenilin 1, which may have considerable pathogenic and therapeutic relevance.

Thorium(IV) removal from aqueous medium by citric acid treated mangrove endophytic fungus Fusarium sp. #ZZF51

Thorium(IV) biosorption is investigated by citric acid treated mangrove endophytic fungus Fussarium sp. #ZZF51 (CA-ZZF51) from South China Sea. The biosorption process was optimized at pH 4.5, equilibrium time 90 min, initial thorium(IV) concentration 50 mg L(-1) and adsorbent dose 0.6 g L(-1) with 90.87% of removal efficiency and 75.47 mg g(-1) of adsorption capacity, which is obviously greater than that (11.35 mg g(-1)) of the untreated fungus Fussarium sp. #ZZF51 for thorium(IV) biosorption under the condition of optimization. The experimental data are analyzed by using isotherm and kinetic models. Kinetic data follow the pseudo-second-order model and equilibrium data agree very well with the Langmuir model. In addition, FTIR analysis indicates that hydroxyl, amino, and carbonyl groups act as the important roles in the adsorption process.

Do adult focused anti-smoking campaigns have an impact on adolescents? The case of the Australian National Tobacco Campaign

OBJECTIVES

To examine adolescents' awareness of and response to an adult focused anti-smoking advertising campaign.

DESIGN AND SETTING

Data were obtained from two cross sectional surveys of adolescents. The first study, a national evaluation study, involved a telephone survey of a randomly selected sample of 400 14-17 year olds across Australia in 1998. The second study involved a survey of 3714 students aged 12-17 years, randomly selected from a probability sample of secondary schools in the Australian State of Victoria.

MAIN OUTCOME MEASURES

In both surveys, adolescents answered questions on their awareness of the advertising campaign and actions taken in response to the campaign. Adolescents in the national evaluation study also answered questions assessing knowledge of health effects of smoking, impact of the campaign on adolescents, and relevance of the campaign for adolescents and other groups. Responses for smokers and nonsmokers were examined.

RESULTS

Among the national evaluation sample, 85% of adolescent smokers thought the campaign was relevant to them. Fifty three per cent indicated that the campaign had led some teenagers to at least try to quit and 85% thought it made smoking seem less cool and desirable. Among students who were established smokers the campaign generated quitting activity, with 27% cutting down the number of cigarettes they smoked and 26% having thought about quitting.

CONCLUSION

Results indicate that adolescents were very aware of this adult focused anti-smoking campaign and thought it relevant to them. The findings suggest that a graphic health effects cessation focused campaign may have been successful in promoting anti-smoking attitudes among adolescents.

Deep brain stimulation in the medial septum attenuates temporal lobe epilepsy via entrainment of hippocampal theta rhythm

Aims

Temporal lobe epilepsy (TLE), often associated with cognitive impairment, is one of the most common types of medically refractory epilepsy. Deep brain stimulation (DBS) shows considerable promise for the treatment of TLE. However, the optimal stimulation targets and parameters of DBS to control seizures and related cognitive impairment are still not fully illustrated.

Methods

In the present study, we evaluated the therapeutic potential of DBS in the medial septum (MS) on seizures and cognitive function in mouse acute and chronic epilepsy models.

Results

We found that DBS in the MS alleviated the severity of seizure activities in both kainic acid‐induced acute seizure model and hippocampal‐kindled epilepsy model. DBS showed antiseizure effects with a wide window of effective stimulation frequencies. The antiseizure effects of DBS were mediated by the hippocampal theta rhythm, as atropine, which reversed the DBS‐induced augmentation of the hippocampal theta oscillation, abolished the antiseizure effects of DBS. Further, in the kainic acid‐induced chronic TLE model, DBS in the MS not only reduced spontaneous seizures, but also improved behavioral performance in novel object recognition.

Conclusion

DBS in the MS is a promising approach to attenuate TLE probably through entrainment of the hippocampal theta rhythm, which may be therapeutically significant for refractory TLE treatment.

Near-infrared monitoring of tissue oxygenation during application of lower body pressure at rest and during dynamical exercise in humans

During the application of a wide range of graded lower body pressures (LBP) (-50 to 50 mmHg), we examined how (1) the tissue oxygenation in the lower and upper parts of the body changes at rest, and (2) how tissue oxygenation changes in the lower extremities during dynamical leg exercise. We used near-infrared spectroscopy (NIRS) to measure the changes induced by LBP in total Hb content and Hb oxygenation in seven subjects. At rest, total Hb increased and Hb oxygenation decreased in the thigh muscles during -25 and -50 mmHg LBP, while both decreased during +25 and +50 mmHg LBP. However, in the forearm muscles during graded LBP, the pattern of change in total Hb was the reverse of that in the thigh. Measurements from the forehead showed changes only during +50 mmHg LBP. These results demonstrated that the pattern of change in total Hb and Hb oxygenation differed between upper and lower parts with graded LBP at rest. During dynamical leg exercise, total Hb and Hb oxygenation in the thigh muscles decreased during stepwise increases in LBP above -25 mmHg, Hb oxygenation decreasing markedly during +50 mmHg LBP. These results suggest that during dynamical exercise (i) LBP at +25 mmHg or more causes a graded decline in blood volume and/or flow in the thigh muscles, and (ii) especially at +50 mmHg LBP, the O2 content may decrease markedly in active muscles. Our results suggest that NIRS can be used to monitor in a non-invasive and continuous fashion the changes in oxygenation occurring in human skeletal muscles and head during the graded changes in blood flow and/or volume caused by changes in external pressure and secondary reflexes both at rest and during dynamical exercise.