Biomedical subjects

C M Cook

Publications and source records attributed to C M Cook.

At least 19 recordsLinked to original sources

PubMed2006

Exposure to ELF magnetic and ELF-modulated radiofrequency fields: the time course of physiological and cognitive effects observed in recent studies (2001-2005).

In 2002, we published a review of the cognitive and physiological effects of extremely low frequency magnetic fields (ELF MFs) and ELF-modulated radiofrequency fields associated with mobile phones. Since the original preparation of that review, a significant number of studies have been published using techniques such as electroencephalography, event-related potentials and positron emission tomography to investigate electromagnetic field effects upon human physiology and various measures of performance (cognitive, perceptual, behavioral). We review these recent studies, and when effects were observed, we reference the time course of observed effects (immediate or delayed). In our concluding remarks, we discuss a number of variables that are not often considered in human bioelectromagnetics studies, such as personality, individual differences and the specific laterality of ELF MF and mobile phone exposure over the brain. We also consider the sensitivity of various physiological assays and performance measures in the study of biological effects of electromagnetic fields.

Cell Phone↗

PubMed2002

Human electrophysiological and cognitive effects of exposure to ELF magnetic and ELF modulated RF and microwave fields: a review of recent studies.

The investigation of weak (<500 microT), extremely low frequency (ELF, 0-300 Hz) magnetic field (MF) exposure upon human cognition and electrophysiology has yielded incomplete and contradictory evidence that MFs interact with human biology. This may be due to the small number of studies undertaken examining ELF MF effects upon the human electroencephalogram (EEG), and the associated analysis of evoked related potentials (ERPs). Relatively few studies have examined how MF exposure may affect cognitive and perceptual processing in human subjects. The introduction of this review considers some of the recent studies of ELF MF exposure upon the EEG, ERPs and cognitive and perceptual tasks. We also consider some of the confounding factors within current human MF studies and suggest some new strategies for further experimentation.

Cognition↗

PubMed2002

Neurobehavioral and neurometabolic (SPECT) correlates of paranormal information: involvement of the right hemisphere and its sensitivity to weak complex magnetic fields.

Experiments were designed to help elucidate the neurophysiological correlates for the experiences reported by Sean Harribance. For most of his life he has routinely experienced "flashes of images" of objects that were hidden and of accurate personal information concerning people with whom he was not familiar. The specificity of details for target pictures of people was correlated positively with the proportion of occipital alpha activity. Results from a complete neuropsychological assessment, Single Photon Emission Computed Tomography (SPECT), and screening electroencephalography suggested that his experiences were associated with increased activity within the parietal lobe and occipital regions of the right hemisphere. Sensed presences (subjectively localized to his left side) were evoked when weak, magnetic fields, whose temporal structure simulated long-term potentiation in the hippocampus, were applied over his right temporoparietal lobes. These results suggest that the phenomena attributed to paranormal or "extrasensory" processes are correlated quantitatively with morphological and functional anomalies involving the right parietotemporal cortices (or its thalamic inputs) and the hippocampal formation.

Alpha Rhythm↗

PubMed2002

Remote viewing with the artist Ingo Swann: neuropsychological profile, electroencephalographic correlates, magnetic resonance imaging (MRI), and possible mechanisms.

In the present study, the artist Ingo Swann, who helped develop the process of remote viewing (awareness of distant objects or places without employing normal senses), was exposed during a single setting of 30 min. to specific patterns of circumcerebral magnetic fields that significantly altered his subjective experiences. Several times during subsequent days, he was asked to sit in a quiet chamber and to sketch and to describe verbally distant stimuli (pictures or places) beyond his normal senses. The proportions of unusual 7-Hz spike and slow wave activity over the occipital lobes per trial were moderately correlated (rho=.50) with the ratings of accuracy between these distal, hidden stimuli and his responses. A neuropsychological assessment and Magnetic Resonance Imaging indicated a different structural and functional organization within the parieto-occipital region of the subject's right hemisphere from organizations typically noted. The results suggest that this type of paranormal phenomenon, often dismissed as methodological artifact or accepted as proofs of spiritual existence, is correlated with neurophysiological processes and physical events. Remote viewing may be enhanced by complex experimentally generated magnetic fields designed to interact with the neuromagnetic "binding factor" of consciousness.

Art↗

PubMed2002

Enhancement of images of possible memories of others during exposure to circumcerebral magnetic fields: correlations with ambient geomagnetic activity.

On the basis of results from a special subject who reported information at a distance during exposure to weak, circumcerebral magnetic fields rotating within the horizontal plane, we designed an experiment to discern if the subjective narratives of normal people exposed to these fields could be similar to the comments of emotionally related individuals who were concurrently generating shared memories about a randomly selected stimulus. Blind matching of the comments indicated that the proportions of 44 students who accurately paired the narratives of the field-exposed subject and the comments of the stimulus person as congruent were statistically significant for 5 of the 7 pairs whose narratives were of sufficient length for analysis. The ratings for congruence of the pairs of verbal behaviors for the 7 pairs of subjects were negatively correlated (rho = -.72) with the geomagnetic activity during the 24-hr. interval within which the experiences were conducted. The results suggested consciousness might also be an insulator to myriad stimuli which might be accessible when brain activity is modified by circumcerebral magnetic fields with temporal configurations in the order of 20 msec.

Adult↗

PubMed2001

A comparison of rheumatoid arthritis and fibromyalgia patients and healthy controls exposed to a pulsed (200 microT) magnetic field: effects on normal standing balance.

Specific weak time varying pulsed magnetic fields (MF) have been shown to alter animal and human behaviors, including pain perception and postural sway. Here we demonstrate an objective assessment of exposure to pulsed MF's on Rheumatoid Arthritis (RA) and Fibromyalgia (FM) patients and healthy controls using standing balance. 15 RA and 15 FM patients were recruited from a university hospital outpatient Rheumatology Clinic and 15 healthy controls from university students and personnel. Each subject stood on the center of a 3-D forceplate to record postural sway within three square orthogonal coil pairs (2 m, 1.75 m, 1.5 m) which generated a spatially uniform MF centered at head level. Four 2-min exposure conditions (eyes open/eyes closed, sham/MF) were applied in a random order. With eyes open and during sham exposure, FM patients and controls appeared to have similar standing balance, with RA patients worse. With eyes closed, postural sway worsened for all three groups, but more for RA and FM patients than controls. The Romberg Quotient (eyes closed/eyes open) was highest among FM patients. Mixed design analysis of variance on the center of pressure (COP) movements showed a significant interaction of eyes open/closed and sham/MF conditions [F=8.78(1,42), P<0.006]. Romberg Quotients of COP movements improved significantly with MF exposure [F=9.5(1,42), P<0.005] and COP path length showed an interaction approaching significance with clinical diagnosis [F=3.2(1,28), P<0.09]. Therefore RA and FM patients, and healthy controls, have significantly different postural sway in response to a specific pulsed MF.

Adaptation, Physiological↗

PubMed2001

Human standing balance is affected by exposure to pulsed ELF magnetic fields: light intensity-dependent effects.

There is evidence in animals that behavioral and physiological responses to static and extremely low frequency magnetic fields (ELFMF) is affected by the presence of light during magnetic field exposures. Here we report that the effect of a specific pulsed ELFMF (PEMF) on human standing balance is modulated by light intensity during exposure. Under a low light condition (0.12 W/m2), nine healthy human volunteers stood on a 3D forceplate, throughout four 2 min exposures (eyes open/eyes close, sham/PEMF of 200 +/- 1 microTpk, order randomized). There was a significant increase in standing movement during PEMF exposure during eyes closed. In a second experiment on 26 normal subjects exposed to the identical protocol, but at greater light intensities (0.51 W/m2), a significant but opposite effect was observed.

Adult↗

PubMed2001

Geophysical variables and behavior: XCII. Experimental elicitation of the experience of a sentient being by right hemispheric, weak magnetic fields: interaction with temporal lobe sensitivity.

We tested the hypothesis that proportionally more people with above average numbers of complex partial epileptic-like experiences before the experiment would report a proximal presence during applications of a weak (1 microTesla), frequency-modulated magnetic field over the right hemisphere. Each of 16 subjects sat in a darkened, quiet room and was exposed for 20 min. to complex fields, applied through a helmet, either along the right hemisphere or across both hemispheres. None of the 8 subjects with below average scores reported a presence during the applications of the magnetic fields while 75% and 60% of the 8 subjects with above average scores reported a presence during right hemispheric and bilateral stimulation, respectively.

Adult↗

PubMed2000

Dynamic expression and activity of NF-kappaB during post-natal mammary gland morphogenesis.

The Rel/NF-kappaB family of transcription factors has been implicated in such diverse cellular processes as proliferation, differentiation, and apoptosis. As each of these processes occurs during post-natal mammary gland morphogenesis, the expression and activity of NF-kappaB factors in the murine mammary gland were examined. Immunohistochemical and immunoblot analyses revealed expression of the p105/p50 and RelA subunits of NF-kappaB, as well as the major inhibitor, IkappaBalpha, in the mammary epithelium during pregnancy, lactation, and involution. Electrophoretic mobility shift assay (EMSA) demonstrated that DNA-binding complexes containing p50 and RelA were abundant during pregnancy and involution, but not during lactation. Activity of an NF-kappaB-dependent luciferase reporter in transgenic mice was highest during pregnancy, decreased to near undetectable levels during lactation, and was elevated during involution. This highly regulated pattern of activity was consistent with the modulated expression of p105/p50, RelA, and IkappaBalpha.

Animals↗

PubMed2000

The cervix as a predictor of preterm delivery in 'at-risk' women.

OBJECTIVE: To examine the relationship between ultrasound-determined cervical status and pregnancy outcome in women 'at-risk' of spontaneous preterm delivery. DESIGN: A prospective cohort study of 120 pregnant women considered to be 'at-risk' of spontaneous preterm delivery by their clinician. Transvaginal ultrasound of the cervix was used to assess overall cervical length, closed endocervical canal length, diameter and internal os dilatation in the second trimester. The main outcome measure was occurrence of spontaneous preterm birth (< 34 and < 37 weeks of gestation). RESULTS: The overall preterm delivery rate (< 37 weeks gestation) in these women was 35% (n = 42) with 20% (n = 24) delivering < 34 weeks gestation. Of the 71 women with a normal cervix, 8 (11%) delivered < 34 weeks, whereas of the 49 women with an abnormal cervix, 16 (33%) delivered < 34 weeks (RR 2.90; 95% CI 1.35-6.24). Using linear regression, closed endocervical canal length of < 21 mm before 20 weeks is associated with delivery < 34 weeks in 95% of women, and with delivery < 37 weeks in 95% of women if the canal length is < 33 mm. Logistic regression showed closed endocervical canal length to be the only significant factor in those women who delivered < 34 weeks after controlling for possible confounders. CONCLUSIONS: A strong relationship is demonstrated between cervical status and pregnancy outcome, particularly the cervical findings before 20 and 24 weeks of gestation. The length of the closed portion of the endocervical canal is the best predictor. A beneficial effect of this approach to 'at-risk' women is the reduction in unnecessary interventions in those with normal cervical findings.

Adult↗

PubMed2000

Is there a relationship between uterine activity and the length of the cervix in the second trimester?

OBJECTIVE: The purpose of this study was to determine if a relationship could be detected between uterine activity and cervical change in the second trimester. METHODS: Ten women with evidence of cervical change and 10 women with no cervical change (controls) were studied between 20 and 28 weeks gestation. Uterine activity was recorded using home uterine activity monitoring units. Cervical assessment was performed using transvaginal ultrasound. RESULTS: There was no statistically significant difference in the contractions per hour in the cervical change group (1.26 +/- 0.38; mean +/- SEM) compared to the controls (1.13 +/- 0.48) (p 0.48; Mann-Whitney U test). There were significant differences in closed endocervical length (p < 0.001) and internal os dilatation (p 0.004), the cervical change group demonstrating a shorter closed endocervical length and greater internal os dilatation. CONCLUSIONS: This preliminary study shows no evidence of a relationship between uterine activity and endocervical canal length in the second trimester.

Adult↗

PubMed2000

A single amino acid residue on the alpha(5) subunit (Ile215) is essential for ligand selectivity at alpha(5)beta(3)gamma(2) gamma-aminobutyric acid(A) receptors.

Imidazobenzodiazepines such as RY-80 have been reported to exhibit both high affinity and selectivity for GABA(A) receptors containing an alpha(5) subunit. A single amino acid residue (alpha(5)Ile215) has been identified that plays a critical role in the high-affinity, subtype-selective effects of RY-80 and structurally related ligands. Thus, substitution of alpha(5)Ile215 with the cognate amino acid contained in the alpha(1) subunit (Val211) reduced the selectivity of RY-80 for alpha(5)beta(3)gamma(2) receptors from approximately 135- to approximately 8-fold compared with alpha(1)beta(3)gamma(2) receptors. This mutation produced a comparable reduction in the selectivity of RY-24 (a structural analog of RY-80) for alpha(5)beta(3)gamma(2) receptors but did not markedly alter the affinities of ligands (e.g., flunitrazepam) that are not subtype-selective. Conversely, substitution of the alpha(1) subunit with the cognate amino acid contained in the alpha(5) subunit (i.e., alpha(1)V211I) increased the affinities of alpha(5)-selective ligands by a approximately 20-fold and reduced by 3-fold the affinity of an alpha(1)-selective agonist (zolpidem). Increasing the lipophilicity (e.g., by substitution of Phe) of alpha(5)215 did not significantly affect the affinities (and selectivities) of RY-80 and RY-24 for alpha(5)-containing GABA(A) receptors. However, the effect of introducing hydrophilic and or charged residues (e.g., Lys, Asp, Thr) at this position was no greater than that produced by the alpha(5)I215V mutation. These data indicate that residue alpha(5)215 may not participate in formation of the lipophilic L(2) pocket that has been proposed to contribute to the unique pharmacological properties of alpha(5)-containing GABA(A) receptors. RY-80 and RY-24 acted as inverse agonists in both wild-type alpha(5)beta(3)gamma(2) and mutant alpha(5)I215Kbeta(3)gamma(2) receptors expressed in Xenopus laevis oocytes. However, both RY-24 and RY-80 acted as antagonists at mutant alpha(5)I215Vbeta(3)gamma(2) and alpha(5)I215Tbeta(3)gamma(2) receptors, whereas the efficacy of flunitrazepam was similar at all three receptor isoforms. The data demonstrate that amino acid residue alpha(5)215 is a determinant of both ligand affinity and efficacy at GABA(A) receptors containing an alpha(5) subunit.

Alkynes↗

PubMed1999

Subjective time estimation by humans is increased by counterclockwise but not clockwise circumcerebral rotations of phase-shifting magnetic pulses in the horizontal plane.

Volunteers were required to estimate 10-s intervals after 2.5 min exposures to each of six different patterns of complex magnetic fields. The approximately 10 microT fields were applied sequentially through eight solenoids that were arranged circumcerebrally (every 45 deg) at the level of the temporoorbital plane. There were three rates of change for the circumcerebral rotations whose durations ranged between about 200 and 2000 ms. Successive additions of 20 ms of the complex fields during the counterclockwise circumcerebral rotation at each solenoid distended subjective time most effectively. Subjective time of the group who received these counterclockwise rotations was about 3 s longer than the group who received the clockwise rotations (explaining approximately 50% of the variance). The results are consistent with the model that the temporal binding for experience, most likely a feature of the rostrocaudal waves recreated every approximately 20 ms over the cerebral cortices, can be modified by weak magnetic fields whose spatial direction and temporal complexity are designed to interact with this process.

Adult↗

PubMed1999

The relationship of rural persons' multidimensional health locus of control to knowledge of cancer, cancer myths, and cancer danger signs.

The purpose of the study was to determine if a relationship exists between multidimensional health locus of control and knowledge of breast cancer, prostate cancer, cancer myths, and danger signs. A descriptive correlational design was used. A convenience sample of 78 rural men and 79 rural women participated in the study. Participants completed three questionnaires: (a) the Cancer Danger Signs Questionnaire, (b) the Cancer Myths Questionnaire, (c) the Prostate Cancer Knowledge Test (completed by the men) and the Breast Cancer Knowledge Test (completed by the women). Results indicated that an internal score on the Multidimensional Health Locus of Control (MHLOC) scale did not predict knowledge of breast cancer in women, prostate cancer in men, cancer myths, or danger signs. Women who scored high on the Powerful Others subscale of the MHLOC had statistically significant high scores on knowledge of breast cancer, but not on cancer myths and danger signs. The MHLOC and its subscales did not predict knowledge of prostate cancer, cancer myths, or cancer danger signs for the male participants. The implications of these results for rural nursing practice and their relationship to previous research are discussed.

Adult↗

PubMed1999

A randomized clinical trial comparing oral misoprostol with synthetic oxytocin or syntometrine in the third stage of labour.

This is a multicentre, blocked, randomized trial to compare the efficacy of oral misoprostol 400 microg with current injectable uterotonic agents (oxytocin/ Syntometrine) used prophylactically in the third stage of labour. Main outcome measures were blood loss, use of a second uterotonic agent and difference in haemoglobin level from antepartum to postpartum. Data analysis from 863 women showed a statistically significant increase in both the mean blood loss (p < 0.001) and the rate of postpartum haemorrhage > 500 mL, (RR 2.72: 95% C1 1.73-4.27) in the misoprostol group compared to the oxytocin/Syntometrine group. The use of a second uterotonic agent was higher in the misoprostol group (RR 2.89: 95% Cl 2.00-4.18) as well as a greater decrease in postpartum haemoglobin (p = 0.015). Oral misoprostol 400 microg is significantly less effective than the traditional intramuscular uterotonic agents currently used and therefore cannot be considered as a viable option to these agents in the management of the third stage of labour.

Administration, Oral↗

PubMed1999

Success habits of long-term gastric bypass patients.

BACKGROUND: By identifying common habits of the most successful long-term gastric bypass patients, one is able to establish more specific guidelines for new patients to follow. The first postoperative year is a critical time that must be dedicated to changing old behavior and forming new, lifelong habits. METHODS: 100 gastric bypass patients from 1979 to 1995 participated in a comprehensive survey. Surveys were completed in person, by phone, or in writing. Participants were asked to answer questions regarding their eating, drinking, sleeping, exercise, and personal habits. RESULTS: The survey revealed that specific habits are common in gastric bypass patients who have maintained their weight loss for many years. CONCLUSION: Identifying and defining the common habits of patients who are successful with long-term weight loss enabled specific guidelines to be established for new patients to implement during the initial weight loss phase, which will contribute to life-long success.

Data Collection↗

PubMed1998

Cervical trauma: rationale for selecting the appropriate fusion technique.

The selection of the appropriate surgical approach in the management of an unstable cervical spine injury is predicated on the biomechanic deficiencies of the bony and ligamentous structures, the age of the patient, the level of experience of the surgeon, and the concomitant medical comorbidities. The optimal approach ideally is the least invasive, provides the greatest benefit-to-risk ratio in terms of potential injury to contiguous neurovascular structures, and provides adequate stabilization to avoid cumbersome external immobilization and allows early rehabilitation. This article discusses anterior, posterior, and combined stabilization techniques in patients who have sustained trauma to the upper and lower cervical spine.

Atlanto-Occipital Joint↗

PubMed1998

Design and synthesis of small molecule interleukin-1 receptor antagonists based on a benzene template.

The interleukin-1 proteins (IL-1 alpha and IL-1 beta) are key mediators of inflammatory and immunological responses, and several in vitro and in vivo studies with protein-based antagonists have demonstrated the potential usefulness of IL-1 receptor antagonists to treat various inflammation related diseases. Based on the X-ray crystal structures of IL-1 ligands and site-directed mutagenesis data, a noncontiguous binding epitope encompassing Arg4, Phe46, Ile56, Lys93, Lys103, and Glu105 for IL-1 beta was proposed. In this paper we describe the synthesis and binding assay results of small molecule IL-1 receptor antagonists designed on the basis of the three-dimensional structure of the binding epitope. Among these, the compound 45 was found to inhibit IL-alpha binding to the Type I receptor with an IC50 value of 3 microM. A hypothesis generated using BioCad CATALYST program is also presented to rationalize these observations.

Benzene Derivatives↗