Overweight and Obese Pet Owners: Respondent and Pet Characteristics in the Rural Midwestern United States

The obesity epidemic has impacted both people and pets in the rural Midwestern United States (MWUS). Tailoring health advice to the socio-demographic characteristics and dietary patterns of owners and their pets can help promote adherence to health behavior changes for owners and foster health improvements for both owners and pets. The authors completed this cross-sectional study in the rural MWUS with the objective of describing health-related characteristics of non-over-weight/obese versus overweight/obese [NOO vs. OO] cat and dog owners and their pets. The primary aim was to detect differences that could inform health recommendations. For both cat and dog owners, dietary and lifestyle profiles differed between those who were non-overweight/obese and those who were overweight/obese. NOO dog owners trended toward fewer health problems, took fewer medications (p < 0.02), took more supplements (p < 0.03), and ate less fast food (p < 0.03) and more fish (p < 0.001) than OO owners. Dogs owned by NOO owners had more owner-initiated activity (M ± SD: 44.6 ± 63.0 vs. 27.2 ± 26.4 min/d) and were on more supplements (p < 0.003). NOO cat owners were younger (p < 0.03), had fewer health problems (p < 0.04), took fewer medications (p < 0.04), engaged in more exercise (p < 0.02), and ate less fast food (p < 0.03) than OO cat owners. The only significant difference between cats of NOO vs. OO owners was their predominant gender: 57% vs. 74% female (p < 0.01). These findings have implications for marketing, education, and health care for both owners and pets. Further investigation of the relationship between pet ownership and health is warranted.     

Pet's Presence and Owner's Blood Pressures during the Daily Lives of Pet Owners with Pre- to Mild Hypertension

ABSTRACT

As the population ages the number of older adults living with hypertension (HTN) is rising dramatically. Uncontrolled HTN increases cardiovascular and renal mortality. Ambulatory (A) blood pressure (BP) is a better predictor of HTN-related morbidity and mortality than office BP. Lower BP is the most important therapeutic goal in treating HTN. Any reduction in BP has significant benefits for older adults. The current study was designed to evaluate the impact of the presence of pet dogs and cats on ABP during the daily lives of independently living, older pet owners with pre- to mild HTN. A repeated measures observational study of ABP of 32 pet owners (21 dogs, 8 cats, 3 cat and dog; 29 women) aged 50–83 years with BP 120–150/80–100 mmHg or < 150/100 with anti-hypertensive medication was conducted. Owner's ABPs were recorded every 20 minutes for one day during waking hours at study entry, one month, and three months. Activity monitors and diaries were used to obtain information about activity, mood, and whether the pet and/or another person was present in the room (indoors) or in close proximity (outdoors) with the owner at each assessment. Generalized estimating equation (GEE) analyses for hierarchical data (unstructured correlations) were performed for systolic and diastolic ABP. Mean ABPs were significantly (systolic BP/diastolic BP: dog p = 0.008/ p = 0.002; cat p < 0.009/ p < 0.001) different (systolic BP/diastolic BP mmHg: dog 3.1/1.5; cat –3.0/2.2) when pets were present after controlling for participant's mood (p > 0.05/ p < 0.001), activity intensity (p = 0.026/ p = 0.441), location (p = 0.013/ p = 0.004), and the presence of other people (p = 0.947/ p = 0.723). The presence of a dog was associated with lower systolic and diastolic BP and of a cat was associated with lower diastolic BP and higher systolic BP during their owners' normal daily lives. This finding suggests that pets, especially dogs, may be effective as an adjunctive intervention to slow the development or progression of HTN in older adults. Comparison of ABPs of pet owners with non-owners during their daily lives is warranted and underway.     

Behavioral Responses of Nursing Home Residents to Visits From a Person with a Dog,a Robot Seal or aToy Cat

Previous studies suggest that contact with dogs can positively affect the wellbeing of elderly people in nursing homes, but there is a lack of research investigating the causal pathways of these effects. One such path- way may relate to the behavioral responses of the elderly when interacting with a dog. The present study compared the immediate behavioral responses of nursing home residents to bi-weekly visits from a person accompanied by either a dog, a robot seal (PARO®), or a soft toy cat, using a randomized controlled design. A total of 100 nursing home residents com- pleted the study. Each participant received a total of 12 visits, during which their behaviors, including interactions between the visitor and the accom- panying animal (real or artificial), were recorded. Also, data on cognitive im- pairment, presence of depressive symptoms, age, time lived in the nursing home, dementia diagnoses, and gender were collected. We found that the immediate responses to, and interaction with, the visiting animal depended on the type of animal that was brought along. The dog and the interactive robot seal triggered the most interaction, in the form of physical contact (F(2,103) = 7.50, p < 0.001), eye contact (F(4,151) = 6.26, p < 0.001), and verbal communication (F(4,195) = 2.87, p < 0.05). As well, the cognitive impairment level of the residents affected with whom they interacted. The higher the cognitive impairment level, the more interaction was directed toward the animal and less toward humans, regardless of visit type (F(2,101) = 4.10, p < 0.05). The dogs and the robot seal stimulated the residents to more in- teraction, compared with the toy cat, but the robot seal failed to maintain the attention at the same level over time. The cognitive functioning of the residents correlated with the level of interaction, and this needs to be studied further.     

Alteration of neural activity and neuroinflammatory factors in the insular cortex of mice with corneal neuropathic pain

Dry eye disease (DED) affects nearly 55% of people worldwide; several studies have proposed that central sensitization and neuroinflammation may contribute to the developing corneal neuropathic pain of DED, while the underlying mechanisms of this contribution remain to be investigated. Excision of extra orbital lacrimal glands established the dry eye model. Corneal hypersensitivity was examined through chemical and mechanical stimulation, and open field test measured the anxiety levels. Restingstate fMRI is a method of functional magnetic resonance imaging (rs-fMRI) was performed for anatomical involvement of the brain regions. The amplitude of low-frequency fluctuation (ALFF) determined brain activity. Immunofluorescence testing and Quantitative real-time polymerase chain reaction were also performed to further validate the findings. Compared with the Sham group, ALFF signals in the supplemental somatosensory area, secondary auditory cortex, agranular insular cortex, temporal association areas, and ectorhinal cortex brain areas were increased in the dry eye group. This change of ALFF in the insular cortex was linked with the increment in corneal hypersensitivity (p < 0.01), c-Fos (p < 0.001), brain-derived neurotrophic factor (p < 0.01), TNF-α, IL-6, and IL-1β (p < 0.05). In contrast, IL-10 levels (p < 0.05) decreased in the dry eye group. DED-induced corneal hypersensitivity and upregulation of inflammatory cytokines could be blocked by insular cortex injection of Tyrosine Kinase receptor B agonist cyclotraxin-B (p < 0.01) without affecting anxiety levels. Our study reveals that the functional activity of the brain associated with corneal neuropathic pain and neuroinflammation in the insular cortex might contribute to dry eye-related corneal neuropathic pain.     

Measurement by ELISA of Complement Factor 4 (C4) in the Rat Brain: Necessity for Removal of Cerebrovascular Proteins

Assessment of complement 4 (C4) levels in experimental animals is used as a marker for activation of the classical complement pathway. The objective of this study was to develop a method for measuring C4 concentrations in the rat brain. An ELISA (sensitivity = 0.5 ng C4/ml) was used to measure C4 in regional brain homogenates from Fischer rats cardiac-perfused with phosphate buffered saline to remove cerebrovascular contents, and from sham-perfused rats. Ventral midbrain C4 levels were increased (p < 0.001) versus frontal cortex and striatum in sham-perfused rats, whereas after perfusion there were no differences between brain regions. Removal of cerebrovascular contents decreased C4 by 43% in striatum, 52% in frontal cortex, and 69% in ventral midbrain (all p < 0.01 versus sham-perfused means). These results indicate that C4 in the rat brain can be measured quantitatively by ELISA provided that cerebrovascular proteins are removed by perfusion.     

Heart Rate Variability During a Working Memory Task: Does Touching a Dog or Person Affect the Response?

The presence of a dog has been associated with reduced responses to stressors in several, but not all, previous studies. The presence of a dog has also been related to improved performance on some cognitive tasks. The current study was designed to evaluate the effect of touching a dog on stress responses to a working memory task (WMT). Heart rate variability (HRV) responses to a WMT while touching a dog were compared with responses while touching a stuffed dog and a person. HRV was recorded while 53 university students aged 18 to 41 years sat on the floor next to a randomly assigned co-participant (real dog, stuffed dog, or human) and listened to a reading before and after completing a WMT. This procedure was repeated with the two other co-participants, in a randomized block order. All participants wore an HRV monitor and placed their non-dominant hand on the co-participant throughout the appropriate phase. The WMT involved pointing to increasingly complicated sequences of geometric shapes until the participant failed three times at one level. Linear mixed models analysis for nested data revealed that the memory task was stressful, with parasympathetic nervous system arousal significantly lower during the memory task than the preor post-memory listening tasks (rMSSD: ps < 0.001, = 0.023; high frequency: ps < 0.001, = 0.001). Neither of the measures differed significantly among the three conditions. There also were no significant interactions, indicating that the stress response to the memory task did not differ when the participants were touching the three different co-participants. Touching a dog did not reduce arousal in response to a stressful memory task. This research suggests that a dog may not be effective at reducing stress responses to this type of stressor. Another possibility is that the presence of a dog is more effective than touching a dog at reducing stress responses. Further investigation will be required to evaluate these possibilities.     

Topographic EEG mapping of the relaxation response

The purpose of this study was to assess the central nervous system effects of the relaxation response (RR) in novice subjects using a controlled, within-subjects design and topographic EEG mapping as the dependent measure. Twenty subjects listened to a RR and control audiotape presented in a counterbalanced order while EEG was recorded from 14 scalp locations. TheRR condition produced greater (p<.0164) reductions in frontal EEG beta activity relative to the control condition. No significant differences were observed for any other frequency band or scalp region. These findings suggest that elicitation of the RR produces significant reductions in cortical activation in anterior brain regions in novice subjects.     

Effect of Parietal Transcranial Magnetic Stimulation on Spatial Working Memory in Healthy Elderly Persons - Comparison of Near Infrared Spectroscopy for Young and Elderly

In a previous study, we succeeded in improving the spatial working memory (WM) performance in healthy young persons by applying transcranial magnetic stimulation (TMS) to the parietal cortex and simultaneously measuring the oxygenated hemoglobin (oxy-Hb) level using near-infrared spectroscopy (NIRS). Since an improvement in WM was observed when TMS was applied to the right parietal cortex, the oxy-Hb distribution seemed to support a model of hemispheric asymmetry (HA). In the present study, we used the same study design to evaluate healthy elderly persons and investigated the effect of TMS on WM performance in the elderly, comparing the results with those previously obtained from young persons. The application of TMS did not affect WM performance (both reaction time and accuracy) of 38 elderly participants (mean age  = 72.5 years old). To investigate the reason for this result, we conducted a three-way ANOVA examining oxy-Hb in both young and elderly participants. For the right parietal TMS site in the elderly, TMS significantly decreased the oxy-Hb level during WM performance; this result was the opposite of that observed in young participants. An additional three-way ANOVA was conducted for each of the 52 channels, and a P value distribution map was created. The P value maps for the young participants showed a clearly localized TMS effect for both the WM and control task, whereas the P map for the elderly participants showed less significant channels and localization. Further analysis following the time course revealed that right-side parietal TMS had almost no effect on the frontal cortex in the elderly participants. This result can most likely be explained by age-related differences in HA arising from the over-recruitment of oxy-Hb, differentiation in the parietal cortex, and age-related alterations of the frontal-parietal networks.     

Biopsychosocial Factors and Cognitive Function in Cat Ownership and Attachment in Community-dwelling Older Adults

ABSTRACT

Few studies consider the health benefits of pet ownership from a biopsychosocial perspective, and a paucity of studies investigate cat ownership. The current study was designed to determine if psychosocial factors (stress, loneliness, and depression), biological levels of stress and inflammation (salivary cortisol, interleukin-1β, and C-reactive protein [CRP]), and cognitive function were associated with companion cat ownership/attachment in community-dwelling older adults. Community-dwelling older adults (n = 96, mean age = 76.6 years) who either owned a cat and no dog (n = 41) or owned neither a cat nor a dog (n = 55) completed questionnaires (Perceived Stress Scale, Revised–UCLA Loneliness Scale, Geriatric Depression Scale-Short Form, Montreal Cognitive Assessment, and Lexington Attachment to Pets Scale) and provided saliva specimens which were assayed for stress and inflammatory biomarkers. The majority of participants screened positive for mild cognitive impairment, reported low levels of stress, loneliness, and depression, and the biomarkers reflected fairly low levels of stress and inflammation. Binary logistic regression analysis revealed that psychosocial factors, salivary biomarkers, and cognitive function were not significantly associated with cat ownership. Age was the only significant predictor of cat ownership (OR = 0.92, p < 0.01) with the odds of cat ownership decreasing by 8.3% per year of advancing age. On average, cat owners were “somewhat attached” to their cats; however, 26% were “strongly attached” to their cats. Correlation analyses revealed the level of attachment to cats was not associated with study outcomes. These results show that cat ownership declined with each advancing year, which lessens the opportunity for older adults to form attachment bonds. The level of pet attachment supports the consideration of cats as a source of an attachment relationship for older adults, including those with cognitive impairment.     

Addition of citrus pulp and apple pomace in diets for dogs: influence on fermentation kinetics,digestion, faecal characteristics and bacterial populations

Fermentation kinetics, digestibility, faecal characteristics and bacterial populations (aerobes, anaerobes, lactobacilli, lactic acid bacteria, enterococci, coliforms and clostridia) of dog food mixed with citrus pulp and apple pomace were evaluated. The in vitro gas production of a pre-digested dog food mixed with 0, 30, 50 and 70 g/kg dry matter (DM) of citrus pulp or apple pomace was measured, and also an experiment with dogs fed the same dog food with or without the addition of 70 g/kg of either fresh citrus pulp or apple pomace was conducted. Gas production increased linearly (p < 0.001) and quadratically (p < 0.001) as fibre levels augmented. The inclusion of fibre sources in the diets resulted in higher faecal output (p = 0.005) and defecation frequency (p < 0.001), and lower faecal pH (p < 0.001) and digestibility values (p < 0.01). Faecal consistencies and microbial populations did not differ among treatments. The addition of fresh citrus and apple was effective to stimulate the hindgut fermentation, but slightly depressed the digestion.     

Dogs discriminate between barks: The effect of context and identity of the caller

In the present study we explored whether dogs (Canis familiaris) are able to discriminate between conspecific barks emitted in different contexts recorded either from the same or different individuals. Playback experiments were conducted with dogs using barks as stimuli in a habituation–dishabituation paradigm. Barks were recorded in two contexts (stranger at the fence and when the dog was left alone) from different individuals. We found that dogs distinguished between barks emitted in these two contexts and were also able to discriminate between different individuals which were barking in the same context. These findings suggest that dog bark may carry context- and individual-specific information for the conspecifics.     

Effect of Satiation on Brain Activity in Obese and Lean Women

Objective: To investigate the response of the brains of women to the ingestion of a meal. Research Methods and Procedures: We used measures of regional cerebral blood flow (rCBF), a marker of neuronal activity, by positron emission tomography to describe the functional anatomy of satiation, i.e., the response to a liquid meal in the context of extreme hunger (36‐hour fast) in 10 lean (BMI ≤ 25 kg/m²; 32 ± 10 years old, 61 ± 7 kg; mean ± SD) and 12 obese (BMI ≥ 35 kg/m²; 30 ± 7 years old, 110 ± 14 kg) women. Results: In lean and obese women, satiation produced significant increases in rCBF in the vicinity of the prefrontal cortex (p < 0.005). Satiation also produced significant decreases in rCBF in several regions including the thalamus, insular cortex, parahippocampal gyrus, temporal cortex, and cerebellum (in lean and obese women), and hypothalamus, cingulate, nucleus accumbens, and amygdala (in obese women only; all p < 0.005). Compared with lean women, obese women had significantly greater increases in rCBF in the ventral prefrontal cortex and had significantly greater decreases in the paralimbic areas and in areas of the frontal and temporal cortex. Discussion: This study indicates that satiation elicits differential brain responses in obese and lean women. It also lends additional support to the hypothesis that the paralimbic areas participate in a central orexigenic network modulated by the prefrontal cortex through feedback loops.     

Does Physical Contact with a Dog or Person Affect Performance of a Working Memory Task?

ABSTRACT

Working memory (WM) plays a critical role in the execution of a wide variety of cognitive tasks and predicts academic success. This study was designed to compare the impact of the presence of a dog or a person, and physical contact with them, on the performance of a WM task. It also exam- ined whether the impact differed for two dogs, and whether these factors im- pacted arousal during the WM task. College students (n=31, aged 18–23 years) performed a WM task in five counterbalanced conditions; dog-touch, dog-no-touch, person-touch, person-no-touch, and alone. Participants were randomly assigned to one of two dogs; Miniature Poodle (n=16) or Border Collie (n=15). The WM task involved replicating increasingly complicated se- quences of colored lights by touching them on an iPad^®. Linear mixed model analyses revealed there was a significant interaction between collaborator and touch (p=0.05); best WM scores occurred without touch with either the per- son or the dog present, and worst WM scores occurred when the participant was touching a dog. Analyzing WM test during the dog conditions, touch (p=0.027) and dog breed (p=0.042) contributed independently to it; task completion was worse when the poodle was present and better without touch. Physiological measures [heart rate (HR) and heart rate variability] during the ex- periment indicated that the WM task was physiologically arousing (p<0.001) compared with listening, and HR was higher when touching a person than a dog during the task (p<0.046). These results are consistent with facilitation of performance by the presence of an observer. If there is a beneficial effect on cognition from a dog, physical contact with the dog might not be a necessary component. Aspects of the dog (e.g., breed) are also likely factors in WM task performance. This study highlights the importance of situational characteristics in studies evaluating the impact of companion animals.     

Correlation between Choline Signal Intensity and Acetylcholine Level in Different Brain Regions of Rat

Acetylcholine is an important excitatory neurotransmitter, which plays a crucial role in synaptic transmission. The level of acetylcholine is decreased in the early stages of Alzheimer disease (AD), the most common neurodegenerative disease. Therefore, measurement of acetylcholine in the brain may help the clinical diagnosis of AD. However, the methods used till now to detect the brain acetylcholine level are invasive, which are neither recommended nor acceptable in the clinic. Acetylcholine is synthesized from choline-containing compounds (Cho), the latter can be estimated by noninvasive proton magnetic resonance spectroscopy (¹H MRS). To explore whether the Cho signal intensity could be used to represent the acetylcholine level in the brain, we employed ¹H MRS to detect the Cho signal, and simultaneously, we also used microdialysis and high-performance liquid chromatography (HPLC) to measure the level of acetylcholine in hippocampus, striatum, frontal cortex, and somatosensory barrel field (S1BF cortex) of rats, respectively. The results showed that the correlations between Cho signal intensity and acetylcholine level in hippocampus, striatum, frontal cortex, and S1BF cortex were, respectively, 0.823 (p = 0.044), 0.851 (p = 0.032), 0.817 (p = 0.047), and 0.822 (p = 0.045). The F-values of the regression model were, respectively, 8.404 (p = 0.044), 10.47 (p = 0.032), 8.000 (p = 0.047), and 8.326 (p = 0.045). And the derived regression equations were y = 0.67x + 1.363 (hippocampus), y = 5.398x + 6.684 (striatum), y = 0.656x + 0.564 (frontal cortex), and y = 0.394x + 1.127 (S1BF cortex), respectively (y means acetylcholine, and x means Cho). These data suggest that the Cho signal intensity observed by ¹H MRS may be used as an indicator of acetylcholine level in different brain regions of the rats. X.-C. Wang, X.-X. Du, and Q. Tian equally contributed to the work.     

Interaction with Shelter Dogs Reduces Negative Affect of Adolescents in Substance Use Disorder Treatment

We investigated the effectiveness of a human–animal interaction program, involving dogs from an animal shelter, in improving affect of adolescent males in inpatient treatment for substance use disorder (SUD). We hypothesized that adolescents would experience improvements in affect and attitudes toward activities when participating in human–dog interaction activities (dog-interaction condition) compared with “treatment-as-is” recreational activities (control condition). Participants were assigned to weekly 1-h-long condition activities for 8 weeks (4 weeks per condition). Due to attrition, only the participants’ first and second exposures to each condition were evaluated. Using a withinand between-subjects, repeated measures crossover design, we assessed effects of the two conditions on affective states as indexed by Positive and Negative Affect Scale-Expanded Form (PANAS-X) subscales (mixed linear model, n = 12). Attitudes toward doginteraction and control activities were assessed using a researcher-generated survey (ordered logistic regression, n = 14, mean age = 16.2 years). Condition impacted Hostility (F_(1,31) = 6.55, p < 0.05) and Sadness (F_(1,41) = 4.62, p < 0.05) subscale scores; scores were higher following the control condition and lower following the dog-interaction condition. There was a carryover effect of condition in the previous activity session on Sadness scores during the current activity session (F_(1,41) = 4.32, p < 0.05), suggesting that the prior session experience affected current expectations. In the attitudes survey, the dog-interaction condition elicited more positive responses than the control condition (X² ≥ 4.10, df = 1, p < 0.05). From this exploratory study, we conclude that the dog-interaction activities induced an improvement in affect, specifically within dimensions of negative affect, and participants had a more favorable attitude toward the dog activities than the treatment-as-is activities. Offering activities involving interaction with shelter dogs thus shows promise as a useful method for restoring responsiveness to naturally reinforcing (non-substance-related) affective stimuli in adolescents with SUD.     

Inter- and intraspecies comparisons of fibre type distribution and of succinate dehydrogenase activity in type I,IIA and IIB fibres of mammalian diaphragms

Summary Fibre types in the costal region of the diaphragm muscle of several mammalian species with widely different respiratory rates were examined microphotometrically for succinate dehydrogenase (SDH) activity. Mean activities indicated no significant (p>0.05) difference between the type I and IIA fibres for any of the species examined. SDH activities in type IIB fibres were significantly lower (p<0.05) than either the type I or type IIA fibres in the cat, guinea pig, rat and rabbit whereas in the mouse no difference was found. The dog had no classical type 1B fibres. Analysis of the distribution of SDH activities by fibre type indicated a wide scattering of scores with no distinct separation between fibre types. Large differences in SDH activity were noted between species. Mean SDH activities were highest in the mouse and rat, intermediate in the rabbit and guinea pig and lowest in the cat and dog. These data suggest an association between respiratory rate and aerobic oxidative potential of the various fibre types in diaphragms of the species examined.     

Correlations between hearing and sound production in piranhas

Summary In order to determine whether correlations exist between hearing and the known soundproduction abilities in piranhas (Serrasalmus nattereri), behavioral auditory thresholds were obtained with continuous tones and tone pulses. A new avoidance conditioning method was developed, where fin movements of caged animals were taken as response to a tone. The mean values of the far-field audiogram ranged from –26 dB re. 0.1 Pa at 80 Hz to a low point of about –43 dB between 220–350 Hz and rose to –14 dB at 1500 Hz. The frequency spectrum of typical drumming sounds (barks) covers the range of best hearing (100–600 Hz).Piranhas are able to integrate temporally acoustic signals: in threshold investigations with repeated tone pulses, the thresholds rose approximately exponentially with decreasing pulse duration and repetition rate; thresholds of single pulses were higher with shorter pulses. The temporal patterning of the calls and the temporal integration ability are well correlated in piranhas, optimizing intraspecific detectability and total length of sound production with respect to the fatigue characteristics of drumming muscles and habituation of the neural pacemaker.The lagenae of the piranhas were found to face laterofrontally; this is thought to be a morphological adaptation to sound production, saving the lagenae from excessive strain during activation of the drumming muscles.Abbreviations Cl acoustic condition 1, where a board with the air loudspeaker rested on the experimental tank upon a layer of felt - C2 acoustic condition 2, where the loudspeaker was freely mounted 20 cm above the water surface - d _p pulse duration - f _p pulse repetition rate - D duty cycle     

Topographic analysis of dimension estimates of EEG and filtered rhythms in epileptic patients with complex partial seizures

Nonlinear dynamic properties were analyzed on the EEG and filtered rhythms recorded from healthy subjects and epileptic patients with complex partial seizures. Estimates of correlation dimensions of control EEG, interictal EEG and ictal EEG were calculated. The values were demonstrated on topograms. The delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–13 Hz), beta (13–30 Hz) and gamma (30–40 Hz) components were obtained and considered as signals from the cortex. Corresponding surrogate data was produced. Firstly, the influence of sampling parameters on the calculation was tested. The dimension estimates of the signals from the frontal, temporal, parietal and occipital regions were computed and compared with the results of surrogate data. In the control subjects, the estimates between the EEG and surrogate data did not differ (P > 0.05). The interictal EEG from the frontal region and occipital region, as well as its theta component from the frontal region, and temporal region, showed obviously low dimensions (P < 0.01). The ictal EEG exhibited significantly low-dimension estimates across the scalp. All filtered rhythms from the temporal region yielded lower results than those of the surrogate data (P < 0.01). The dimension estimates of the EEG and filtered components markedly changed when the neurological state varied. For each neurological state, the dimension estimates were not uniform among the EEG and frequency components. The signal with a different frequency range and in a different neurological state showed a different dimension estimate. Furthermore, the theta and alpha components demonstrated the same estimates not only within each neurological state, but also among the different states. These results indicate that the theta and alpha components may be caused by similar dynamic processes. We conclude that the brain function underlying the ictal EEG has a simple mechanism. Several heterogeneous dynamic systems play important roles in the generation of EEG. Received: 10 December 1999 / Accepted in revised form: 8 May 2000     

Acute effects of capacitive and resistive electric transfer (CRet) on the Achilles tendon

This study aimed to investigate the acute effects of capacitive and resistive electric transfer (CRet) on Achilles tendon elongation during muscle contraction, as well as the circulation in the peritendinous region. Sixteen healthy men participated in this study. All 16 participants underwent 2 interventions: (1) CRet trial and (2) CRet without power (sham trial). Tendon elongation was measured four times. Using near-infrared spectroscopy, the blood circulation (volume of total-hemoglobin (Hb), oxygenated hemoglobin (oxy-Hb), and deoxygenated hemoglobin (deoxy-Hb)) was measured for 5 min before the intervention and for 30 min after the intervention. The differences between the measurements obtained before and after intervention were compared between the two interventions. The changes in tendon elongation and deoxy-Hb were not significantly different between the interventions. Total- and oxy-Hb were significantly increased in the CRet trial compared with the sham trial. In addition, the increases in total-Hb and oxy-Hb lasted for 30 min after the CRet intervention (CRet vs. sham: oxy-Hb: F = 8.063, p = 0.001, total-Hb: F = 4.564, p = 0.011). In conclusion, CRet significantly improved blood circulation in the peritendinous region.     

Effects of acute manganese chloride exposure on lipid peroxidation and alteration of trace metals in rat brain

Although manganese (Mn) is an essential element, exposure to excessive levels of Mn and its accumulation in the brain can cause neurotoxicity and extrapyramidal syndrome. We have investigated the differences in the accumulated levels of Mn, the degree of lipid peroxidation, and its effects on the levels of trace elements (Fe, Cu, and Zn) in various regions in the brain of rats having undergone acute Mn exposure. The rats in the dose—effect group were injected intraperitoneally (ip) with MnCl₂ (25, 50, or 100 mg MnCl₂/kg) once a day for 24 h. The Mn significantly accumulated (p<0.05) in the frontal cortex, corpus callosum, hippocampus, striatum, hypothalamus medulla, cerebellum, and spinal cord in each case. The rats in the timecourse group were ip injected with MnCl₂ (50 mg MnCl₂/kg) and then monitored 12, 24, 48, and 72 h after exposure. The Mn accumulated in the frontal cortex, corpus callosum, hippocampus, striatum hypothalamus, medulla, cerebellum, and spinal cord after these periods of time, In both the dose—effect and time-course studies, we observed that the concentration of malondialdehyde, an end product of lipid peroxidation, increased significantly in the frontal cortex, hippocampus, striatum, hypothalamus, medulla, and cerebellum. However, no relationship between the concentrations of Mn in the brain and the extent of lipid peroxidation was observed. In addition, we found that there was a significant increase (p<0.05) in the level of Fe in the hippocampus, striatum, hypothalamus, medulla, and cerebellum, but the Cu and Zn levels had not changed significantly. These findings indicated that Mn induces an increase in the iron level, which provides direct evidence for Fe-mediated lipid peroxidation in the rats' brains; these phenomena might play important roles in the mechanisms of Mn-induced neurotoxicology.