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PubMed2005

Face perception is mediated by a distributed cortical network.

The neural system associated with face perception in the human brain was investigated using functional magnetic resonance imaging (fMRI). In contrast to many studies that focused on discreet face-responsive regions, the objective of the current study was to demonstrate that regardless of stimulus format, emotional valence, or task demands, face perception evokes activation in a distributed cortical network. Subjects viewed various stimuli (line drawings of unfamiliar faces and photographs of unfamiliar, famous, and emotional faces) and their phase scrambled versions. A network of face-responsive regions was identified that included the inferior occipital gyrus, fusiform gyrus, superior temporal sulcus, hippocampus, amygdala, inferior frontal gyrus, and orbitofrontal cortex. Although bilateral activation was found in all regions, the response in the right hemisphere was stronger. This hemispheric asymmetry was manifested by larger and more significant clusters of activation and larger number of subjects who showed the effect. A region of interest analysis revealed that while all face stimuli evoked activation within all regions, viewing famous and emotional faces resulted in larger spatial extents of activation and higher amplitudes of the fMRI signal. These results indicate that a mere percept of a face is sufficient to localize activation within the distributed cortical network that mediates the visual analysis of facial identity and expression.

Adult↗

PubMed1991

[Minimal redistribution of thallium-201 representing reversible ischemia after coronary bypass surgery: value of quantitative analysis of exercise thallium-201 SPECT].

We previously reported the value of minimal redistribution (MR) of thallium-201 in analyzing quantitative polar map analysis (QNT) which correlated well with metabolic activity on FDG-PET. To determine whether ischemic areas that have redistribution are truly reversible, we performed stress and 3-hr delayed thallium-201 SPECT imaging and radionuclide ventriculography (RNV) in 41 patients with coronary artery disease before and after coronary bypass surgery (CABG). Redistribution (RD) was categorized into 4 grades: complete RD (CR), incomplete RD (IR), MR and persistent defect (PD). MR was defined as the segment that showed > or = 2SD improvement in more than 1/3 of the area on QNT, but RD was not evident by visual analysis. 1. QNT identified MR in 30 of 56 segments (54%) where PD is noted by visual inspection. 2. The MR segments showed severer wall motion abnormality (wall motion score: 1.83 +/- 1.12) than did the IR or CR segments (0.99 +/- 1.04) (p < 0.01), but the wall motion was well preserved, compared to the PD segments (2.54 +/- 0.90) (p < 0.01). 3. The grade of RD was compared with improvement in regional perfusion and wall motion on RNV after CABG. Improvement in perfusion was observed in 62 of 77 IR or CR segments (81%) and in 17 of 30 MR segments (57%), but in only 3 of 26 PD segments (12%) (p < 0.01). 4. Similarly, improvement in wall motion was observed in 45 of 57 IR or CR segments (79%) and in 22 of 27 MR segments (81%), but in only 5 of 25 PD segments (20%) (p < 0.01). Thus, the MR segments should be considered reversible after CABG. We conclude that QNT of RD should be performed to detect RD which is slight, yet suggestive of viability.

Aged↗

PubMed2001

Quantification of limited augmentation of myocardial (99m)Tc-tetrofosmin uptake at exercise in stable coronary artery disease.

We evaluated the diagnostic accuracy of a new method for quantitative analysis of myocardial perfusion at exercise using (99m)Tc-tetrofosmin tomographic imaging. (99m)Tc-tetrofosmin imaging of an exercise-rest sequence was performed in 30 patients with coronary artery disease (CAD) and eight age-matched control subjects. The exercise-induced myocardial count increase was calculated as the relative value (per cent increase ratio, %IR) to that at rest by correcting for physical decay for (99m)Tc and injected doses and by a subtraction technique. Exercise and rest (99m)Tc-tetrofosmin images were assessed visually and quantitatively using the per cent peak count and %IR of the myocardial count at exercise. Segments with significant coronary stenosis (diameter stenosis=75% or more) showed a significantly lower %IR than did those without significant coronary stenosis in the CAD patients (37+/-19% vs 63+/-21%, P<0.05). The diagnostic efficacy of visual analysis for detecting coronary stenosis was as follows: sensitivity, 58.1% and specificity, 81.4%. When %IR=37% was used for detecting significant coronary stenosis, sensitivity and specificity increased to 74.2% and 93.2%, respectively. Furthermore, the quantitative analysis significantly (P=0.04) improved the overall diagnostic accuracy from 73.3% to 86.7% compared to that of visual assessment. Thus, augmentation of myocardial (99m)Tc-tetrofosmin uptake at exercise is blunted in the myocardium with significant coronary stenosis. The calculation of myocardial count increase at exercise relative to that at rest can improve the diagnostic value of (99m)Tc-tetrofosmin SPECT imaging and may contribute to more accurate quantification of myocardial ischaemia and impaired tracer uptake in coronary artery disease.

Adult↗

PubMed2003

Pharmacokinetic-pharmacodynamic modeling of rocuronium in case of a decreased number of acetylcholine receptors: a study in myasthenic pigs.

BACKGROUND: In myasthenic patients, the sensitivity for nondepolarizing relaxants is increased and the time course of effect is prolonged due to a reduced number of functional acetylcholine receptors at the neuromuscular junction. The authors investigated both the performance of the link model proposed by Sheiner and a pharmacodynamic-pharmacokinetic model taking into account the number of unbound acetylcholine receptors in myasthenic pigs. METHODS: After obtaining the approval of the Animal Experiments Committee of their institution, the authors studied eight myasthenic pigs and eight control pigs. Myasthenia gravis was induced by injecting Torpedo acetylcholine receptors in weeks 1 and 4. On the day of the experiments, the pigs were anesthetized and intubated, and the appropriate muscles and nerves were prepared for the measurements. Rocuronium was administered by infusion to reach 90% twitch height block. Arterial blood was sampled during onset and offset of effect, and the plasma concentration of rocuronium was measured with high-performance liquid chromatography. Plasma concentration-time effect data were analyzed using two different pharmacokinetic-pharmacodynamic models, the link model according to Sheiner and a pharmacokinetic-pharmacodynamic model taking into account the unbound receptor concentration. Muscles were removed after the experiment for laboratory analysis of the acetylcholine receptor concentration. RESULTS: All eight pigs of the myasthenic group developed clinical signs of myasthenia gravis (muscle weakness) and showed increased sensitivity toward rocuronium. Pharmacokinetic modeling revealed no significant differences between myasthenic and control pigs. In pharmacokinetic-pharmacodynamic analysis, visual inspection as well as the Akaike Information Criterion (3,605 3,769) and the residual SD (3.2 3.6%) revealed a better fit for the unbound receptor model in myasthenic animals compared to the Sheiner model. Pharmacokinetic-pharmacodynamic analysis with the unbound receptor model demonstrated a decreased EC50 of 0.27 micro m (ranging from 0.17 to 0.59 micro m) compared to 2.71 micro m (ranging from 2.42 to 4.43 micro m) in control animals. The results of the Sheiner pharmacokinetic-pharmacodynamic analysis were in the same range. Both the laboratory analysis and pharmacokinetic-pharmacodynamic modeling showed a decrease in receptor concentration of more than 75%. CONCLUSION: Both the Sheiner model and the unbound receptor model may be used to fit plasma concentration-effect data of rocuronium in pigs. The unbound receptor concentration model, however, can explain the observed differences in the time course of effect, based on receptor concentration.

Algorithms↗

PubMed2006

Cortical dynamics of visual/semantic vs. phonological analysis in picture confrontation.

Picture naming covers the main stages of word production from concept retrieval to articulation. Cortical correlates of picture naming have been characterized with both haemodynamic and neurophysiological methods but the association of specific activation patterns with the hypothesized processing stages remains elusive. Here we used categorization tasks to selectively highlight different components of picture confrontation, from visual analysis (VIS) to semantic (SEM) and phonological access (PHON), and compared these time courses of activation with that obtained during picture naming (NAM). Brain activity was recorded with whole-head magnetoencephalography (MEG). Following the initially similar activation patterns in occipital and parietal areas, task effects (stronger activation in NAM/PHON than in SEM/VIS) emerged after 300 ms, in the sustained activation of the left posterior temporal and bilateral inferior frontal cortex, apparently reflecting enhancement of phonological and phonetic/articulatory processing.

Adult↗

PubMed2005

Pattern electroretinogram abnormality and glaucoma.

PURPOSE: To determine the existence of retinal ganglion cell dysfunction and associated risk factors in glaucoma suspects with increased optic disc cupping and normal visual field. DESIGN: Cross-sectional, observational study. PARTICIPANTS: Two hundred glaucoma suspect (GS) patients were identified based on optic disc abnormalities (vertical cup-to-disc ratios [C/D]>0.5; vertical C/D asymmetry >or= 0.2; disc hemorrhages; notching) in association with known glaucoma risk factors (positive family history, African American descent, increased intraocular pressure [IOP]), but normal visual fields. Forty-two patients had early manifest glaucoma (EMG). Sixteen normal black subjects were added to update previous pattern electroretinogram (PERG) normative data and to establish a normal control (NC) group with a racial breakdown comparable with that of the study groups. METHODS: Pattern electroretinograms were recorded simultaneously from both eyes using skin electrodes and automated analysis; visual fields were monitored with standard white-on-white automated perimetry (SAP) central 24-2 program; vertical C/D was evaluated by an independent reader from stereo disc photographs; and univariate and multivariate statistical analysis between PERG and other outcome measures was evaluated. MAIN OUTCOME MEASURES: Pattern electroretinogram amplitude (microV), phase (pi rad), and interocular asymmetry in amplitude and phase (%); and SAP mean deviation (MD; decibels), vertical C/D, age (years), IOP (mmHg), and race (black vs. nonblack). RESULTS: The PERG results were abnormal in at least 1 of the outcome measures in 52% of GS patients and 69% of EMG patients. The PERG amplitude was correlated weakly with both MD (P<0.01) and vertical C/D (P = 0.05). The correlation between PERG amplitude and MD and C/D was stronger (P<0.001) for interocular differences rather than absolute measures. Interocular PERG amplitude asymmetry increased with severity of disease (EMG>GS>NC; P<0.01). The PERG amplitude decline with age was steeper in patients with a more negative MD (P<0.01) and in patients with a more negative MD and a larger vertical C/D (P = 0.06). Black race (but not family history) was associated with lower PERG amplitude (P = 0.005) in GS and EMG patients, but not in normal controls (P = 0.44). CONCLUSIONS: The correlation between PERG abnormality and known risk factors for glaucoma indicates that PERG has a predictive potential for the development or progression of the disease, or both.

Adult↗

PubMed2005

A concerted protocol for the analysis of mineral deposits in biopsied tissue using infrared microanalysis.

The mechanism(s) by which crystals are retained in the kidney resulting in stone disease remains unclear. Intratubular aggregation as well as crystal cell binding, or internalization and translocation, or alternatively nucleation and growth in the interstitial fluid are possible models. Our group is testing the hypothesis that calcium phosphate deposits in kidneys of patients with calcium renal stones arise in unique anatomical regions of the kidney. Furthermore, we believe that their formation is conditioned by specific stone forming pathophysiologies. To test this hypothesis, we performed intra-operative renal papillary biopsies during percutaneous nephrolithotomy of kidneys from 15 idiopathic calcium stone formers as well as kidney tissue from a patient who ingested ethylene glycol, and developed a new protocol to accurately identify the composition of the calcium deposits located in the renal tissue. We developed a new histological approach that incorporated a low-energy (low-E) reflective slide substrate that has similar characteristics to a common microscope slide and infrared absorption microspectroscopy. Infrared absorption microspectroscopy revealed the crystal deposits in the idiopathic calcium oxalate stone formers to be hydroxyapatite in composition with an occasional region of calcium carbonate, while calcium oxalate was the predominant mineral in the kidney of the patient who had ingested ethylene glycol. The results demonstrate that mixed sample types containing tissue and mineralized deposits are easily analyzed while mounted on a low-E slide using the attenuated total internal reflectance (ATR) method. Reflection/absorption (R/A) analysis allows one to quickly survey a tissue section and provides qualitative information about its components. Once interesting sites have been identified by R/A analysis, ATR analysis can then be used to collect the best data possible. ATR analysis provides spectra free from many of the artifacts associated with transmission and R/A analysis, and completes the full picture of the components contained in the crystal deposits and tissue. We present a method of analysis for mineralized materials embedded in kidney tissue that uses readily or easily obtainable materials and instrumentation. The sensitivity of this method allows tissue sections to remain unstained, alleviating the tedious and time-consuming constraints of earlier methods of visual analysis. The present method will save time and training, while simultaneously offering an unbiased analysis of mineralized components that is more accurate and conducive to patient treatments than previous methods.

Biopsy↗

PubMed1991

Calcium binding protein (calbindin-D28k) and glutamate decarboxylase gene expression after kindling induced seizures.

In order to determine whether calcium binding protein (calbindin-D28k or CaBP) and glutamate decarboxylase (GAD) may be involved in the process underlying the generation of seizure activity, changes in CaBP protein and mRNA and in GAD mRNA were examined in the kindling model of epilepsy. Following amygdaloid (AK) and commissure (CK) kindling significant decreases in the concentration of CaBP of 20% and 30%, respectively, were specifically observed in the hippocampal formation. However, using a cDNA specific to mammalian CaBP, Northern analysis of poly(A+) RNA and slot blot analysis of total RNA revealed no changes in the levels of CaBP mRNA in hippocampus, subcortical area (including amygdala, substantia nigra and striatum) or cerebellum of rats sacrificed 30 min, 1 h, 6 h or 24 h after the last kindled seizure. Similarly when these blots were reprobed with a cDNA specific to mammalian GAD, no changes in GAD gene expression were observed. However, fos gene expression was markedly enhanced at 1 h after seizure. We also tested whether changes in CaBP or GAD mRNA could be detected at any of the various stages of the kindling process. Slot blot analysis of cortex, subcortical structures and hippocampus revealed no changes in CaBP or GAD mRNA during the course of commissure kindling. In situ hybridization studies with GAD and CaBP 35S-labeled antisense probes also indicated no obvious changes upon visual analysis of autoradiographs. However, when silver grains were counted, significant changes in GAD mRNA in individual cells in hippocampus and substantia nigra were noted after kindling induced epilepsy. Our results indicate that, unlike fos gene expression, prominent alterations in GAD and CaBP mRNA in gross brain regions (as measured by slot blot and Northern blot analyses) are not observed in the kindling process. However, our in situ hybridization studies suggest that changes in GAD mRNA in individual cells may be involved in the process underlying kindling induced seizure activity.

Animals↗

PubMed2001

Arterial baroreceptors and experimental diabetes.

Alterations of the autonomic reflex control of the cardiovasclar system have been demonstrated in clinical and animal models of insulin-dependent diabetes mellitus. Established neuroaxonal dystrophy is considered the neuropathological hallmark of chronic experimental diabetes. However, the afferent arm of the arterial baroreflex, that is, the carotid sinus nerve and the aortic depressor nerve, has received much less attention in studies dealing with this physiopathological model. The attenuation of the pressure response to bilateral carotid occlusion in conscious rats indicates a derangement of the baroreflex, probably involving an alteration of the carotid sinus nerve. There is histological evidence obtained from adult spontaneous insulin-dependent diabetic rats (strain BB/S) of a carotid sinus nerve with signs of axonal swelling and intramyelinic edema, suggesting diabetic neuropathy. The study of aortic baroreceptor activity in anesthetized rats with short- and long-term streptozotocin diabetes by means of cross-spectral analysis of baroreceptor activity versus arterial pressure revealed a dysfunction in the afferent arm of the baroreflex even during a short period of diabetes. The morphology of the aortic depressor nerve of streptozotocin-diabetic rats indicated axonal atrophy by visual analysis remarkably at the distal segments of the nerves. This finding was confirmed by morphometric study of the myelinated fibers. In conclusion, although studies of the arterial baroreceptors related to experimental diabetes are scanty in the literature, there is electrophysiological and histological evidence demonstrating that the carotid sinus and the aortic depressor nerves are abnormal in this experimental model.

Animals↗

PubMed2006

IsoSVM--distinguishing isoforms and paralogs on the protein level.

BACKGROUND: Recent progress in cDNA and EST sequencing is yielding a deluge of sequence data. Like database search results and proteome databases, this data gives rise to inferred protein sequences without ready access to the underlying genomic data. Analysis of this information (e.g. for EST clustering or phylogenetic reconstruction from proteome data) is hampered because it is not known if two protein sequences are isoforms (splice variants) or not (i.e. paralogs/orthologs). However, even without knowing the intron/exon structure, visual analysis of the pattern of similarity across the alignment of the two protein sequences is usually helpful since paralogs and orthologs feature substitutions with respect to each other, as opposed to isoforms, which do not. RESULTS: The IsoSVM tool introduces an automated approach to identifying isoforms on the protein level using a support vector machine (SVM) classifier. Based on three specific features used as input of the SVM classifier, it is possible to automatically identify isoforms with little effort and with an accuracy of more than 97%. We show that the SVM is superior to a radial basis function network and to a linear classifier. As an example application we use IsoSVM to estimate that a set of Xenopus laevis EST clusters consists of approximately 81% cases where sequences are each other's paralogs and 19% cases where sequences are each other's isoforms. The number of isoforms and paralogs in this allotetraploid species is of interest in the study of evolution. CONCLUSION: We developed an SVM classifier that can be used to distinguish isoforms from paralogs with high accuracy and without access to the genomic data. It can be used to analyze, for example, EST data and database search results. Our software is freely available on the Web, under the name IsoSVM.

Algorithms↗

PubMed2005

A longitudinal study of brain morphometrics using serial magnetic resonance imaging analysis in a canine model of aging.

Longitudinal changes in cortical atrophy, ventricular enlargement, and lesion development in serial MRI scans collected from 47 healthy dogs from 1999 (8-11 years old) to 2002 (11-14 years old) were studied. The first method involved manual region of interest volumetric analysis to examine changes in cerebral and ventricular volume during the three years. No change in cerebral volume was detected but ventricular volume increased significantly each year in 2000, 2001, and 2002. Increased ventricular volume parallels early studies of age-dependent ventricular enlargement in the brain of aging beagle dogs. The second method involved a visual analysis of co-registered serial MRIs for each subject. Consistent with the volumetric results, there was no visible change in cortical thickness indicating no cerebral atrophy, but a significant increase in ventricular size was noted. Visual examination also revealed a significant increase in number of dogs who developed aging lesions over the last 2 years in 2001 and 2002. Additionally, a disproportionate number of lesions were recorded in the frontal cortex and caudate nucleus compared to other brain regions. These lesion findings are consistent with other studies in the aging dog that suggest that the frontal lobes may be particularly vulnerable to age-related changes.

Aging↗

PubMed1991

[Role of MRI in diagnosis of adrenal tumors].

The authors evaluated the ability of magnetic resonance imaging (MRI) at 1.5 T to characterize 33 adrenal masses, using visual analysis and the following quantitative variables: signal intensity ratios of tumor/liver, tumor/muscle, and (tumor--muscle)/(fat--muscle) on T2- and T1-weighted images, and the calculated T2 relaxation time of the adrenal masses. All 15 tumors of less than 3 cm in diameter were visually homogeneous on all pulse sequences, whereas the other 18 tumors of over 3 cm appeared to be inhomogeneous. The signal intensity ratios of tumor/liver and tumor/muscle and the calculated T2 relaxation time were not helpful in distinguishing tumors from one another. The ratios of tumor/fat and (tumor--muscle)/(fat--muscle) were useful in distinguishing pheochromocytoma and myelolipoma from other tumors on T2- and T1-weighted images, respectively. However, differentiation among other adrenal tumors appeared to be difficult. The authors concluded that, although MRI might have considerable potential in characterizing adrenal masses, the use of conventional MRI in such analysis is still quite limited.

Adenoma↗

PubMed2004

Imaging a cognitive model of apraxia: the neural substrate of gesture-specific cognitive processes.

The present study aimed to ascertain the neuroanatomical basis of an influential neuropsychological model for upper limb apraxia [Rothi LJ, et al. The Neuropsychology of Action. 1997. Hove, UK: Psychology Press]. Regional cerebral blood flow was measured in healthy volunteers using H2 15O PET during performance of four tasks commonly used for testing upper limb apraxia, i.e., pantomime of familiar gestures on verbal command, imitation of familiar gestures, imitation of novel gestures, and an action-semantic task that consisted in matching objects for functional use. We also re-analysed data from a previous PET study in which we investigated the neural basis of the visual analysis of gestures. First, we found that two sets of discrete brain areas are predominantly engaged in the imitation of familiar and novel gestures, respectively. Segregated brain activation for novel gesture imitation concur with neuropsychological reports to support the hypothesis that knowledge about the organization of the human body mediates the transition from visual perception to motor execution when imitating novel gestures [Goldenberg Neuropsychologia 1995;33:63-72]. Second, conjunction analyses revealed distinctive neural bases for most of the gesture-specific cognitive processes proposed in this cognitive model of upper limb apraxia. However, a functional analysis of brain imaging data suggested that one single memory store may be used for "to-be-perceived" and "to-be-produced" gestural representations, departing from Rothi et al.'s proposal. Based on the above considerations, we suggest and discuss a revised model for upper limb apraxia that might best account for both brain imaging findings and neuropsychological dissociations reported in the apraxia literature.

Adult↗

PubMedDate not supplied

Lexical and semantic factors influencing picture naming in aphasia.

Picture naming requires early visual analysis, accessing stored structural knowledge, semantic activation, and lexical retrieval. We tested the effect of perceptual, lexical, and semantic variables on the performance of aphasics in picture naming and assessed prevalence of natural categories vs artifact dissociations. Forty-nine aphasics were asked to name 60 pictures, from three natural (animals, fruits, and vegetables) and three artificial categories (tools, furniture, and vehicles). For each item visual (drawing complexity, image agreement), semantic (prototypicality, concept familiarity) and lexical variables (word frequency, name agreement) were available. The effect of these variables showed individual differences; altogether, visual complexity had little influence, whereas lexical and semantic variables were more influential. Name agreement was most important, followed by word frequency. On a multiple single case analysis 10 patients (20%) showed a natural/artificial category dissociation. Five of the six subjects faring better with artifacts were males, and all of four patients faring better with natural categories were females. Interpretations of this finding are discussed.

Adolescent↗

PubMed2001

Comparison of two-dimensional gradient echo, turbo spin echo and two-dimensional turbo gradient spin echo sequences in MRI of the cervical spinal cord anatomy.

The aim of this study was to assess the detectability and distinguishability of the cervical spinal cord, the anterior and posterior spinal roots and of the internal anatomy of the cord (distinction of grey and white matter). For this purpose 20 healthy volunteers were examined using a 1.5 T MR unit with 20 mT/m gradient strength and a dedicated circular polarized neck array coil. Three T2* weighted (w). 2D gradient echo sequences, two T2 w. 2D turbo spin echo (TSE) sequences and one T2 w. 2D turbo gradient spin echo (TGSE) sequence were compared. The multiecho 2D fast low angle shot (FLASH) sequence with magnetization transfer saturation pulse (me FLASH+MTS) yielded the best results for liquor/compact bone, liquor/spinal cord and grey/white matter contrast, as found with regions of interest (ROI) analysis. The single echo 2D FLASH sequence was significantly poorer than the two me FLASH+/-MTS sequences. Two-dimensional TGSE as well as 2D TSE with a 256 matrix and with a 512 matrix yielded the poorest results. In the visual analysis the contrast between liquor and compact bone, liquor and cord as well as liquor and roots was best with me FLASH+MTS, whereas grey/white matter distinction was best using me FLASH-MTS. In conclusion, we would therefore recommend the inclusion of an axial T2* w. multiecho 2D spoiled gradient echo sequence with magnetization transfer saturation pulse and gradient motion rephasing in a MR imaging protocol of the cervical spine.

Adult↗

PubMed2002

An automatic method for the recognition and classification of the A-phases of the cyclic alternating pattern.

OBJECTIVES: The aim of this research has been to introduce an automatic method, simple from the mathematical and computational points of view, for the recognition and classification of the A-phases of the cyclic alternating pattern. METHODS: The automatic method was based on the computation of 5 descriptors, which were derived from the EEG signal and were able to provide a meaningful data reduction. Each of them corresponded to a different frequency band. RESULTS: The computation of these descriptors, followed by the introduction of two suitable thresholds and of simple criteria for logical discrimination, provided results which were in good agreement with those obtained with visual analysis. The method was versatile and could be applied to the study of other important microstructure phenomena by means of very small adaptations. CONCLUSIONS: The simplicity of the method leads to a better understanding and a more precise definition of the visual criteria for the recognition and classification of the microstructure phenomena.

Adult↗

PubMed2005

High homeopathic potencies are different from potentized solvent when investigated with the REDEM technology.

OBJECTIVE: To determine in a series of randomized blinded experiments using the REDEM technology whether differences between high homeopathic potencies and similarly potentized solvent can be detected. DESIGN AND ANALYSIS: A REDEM device was employed as a black box. Samples were measured in a capacitor that was connected to 60 individual oscillator circuits at frequencies between 250 and 930 KHz; their oscillation damping was recorded. In two experiments (3 and 4 replications) stable differences between a potentized 'mother tincture' and potentized solvent were assessed. Statistical analysis was done using ANCOVA. RESULTS: Significant differences (p < 0.01) between remedy and control were found, mostly at the same oscillator frequencies. Those differences found for only one remedy always were at frequencies adjacent to frequencies with differences for other remedies. VISUAL ANALYSIS: Where output curves were not near 0, remedy values were higher than controls. Curves within a replication ran parallel, their distances varied. Between replications, curve shapes and remedy- control differences were similar, however, control curves varied in height. Control and remedy curves between experiments varied in shape. Effects increased with time and sample conductivity. Ethanol 43% as solvent eliminated the observed effects, use of polyethylene containers considerably attenuated them. CONCLUSIONS: A probably physical difference was seen between potentized homeopathic remedies and potentized solvent. The differences are associated with sample age, solvent, and container material. The REDEM technology requires further investigation to determine the nature of the underlying mechanisms of the observed differences.

Analysis of Variance↗

PubMed2002

Cerebral perfusion before and after endovascular or surgical treatment of acutely ruptured cerebral aneurysms: a 1-year prospective follow-up study.

OBJECTIVE: To prospectively determine temporal changes in regional cerebral perfusion in patients with acutely (<72 h) ruptured cerebral aneurysms treated either endovascularly or surgically. METHODS: Cerebral perfusion was measured both before and 1 week after treatment by use of a (99m)Tc-labeled ethyl-cysteine dimer and single-photon emission computed tomographic (SPECT) studies in 46 of 81 consecutive patients included in a prospective randomized study of early treatment of ruptured aneurysms. In addition to visual analysis of the SPECT images, corticocerebellar perfusion ratios were calculated for seven predefined bilateral regions. Late ischemic deficits were evaluated after 12 months by magnetic resonance imaging of the brain. RESULTS: Acute perfusion deficits were commonly seen before treatment. In the visual comparison between the first and second SPECT studies, the number of new or enlarged deficits (P = 0.006) and deficits that expanded from unilateral to bilateral (P = 0.020) significantly increased in the surgical group but not in the endovascular group. In the second SPECT study, surgical patients had decreased corticocerebellar perfusion ratios in the right frontobasal cortex (P = 0.012) compared with the endovascular patients, and in the ipsilateral frontobasal cortex (P = 0.002) and ipsilateral temporal apex (P = 0.002) compared with the contralateral side of the ruptured aneurysm. The 12-month magnetic resonance imaging of the brain revealed no significant difference in the number of ischemic deficits between the endovascular and surgical groups. CONCLUSION: Disturbances in cerebral perfusion both before and after treatment are common. Although no major differences in the findings were detected between patients treated with either clips or coils, progression of perfusion deficits was more common in the surgical group. However, the 12-month magnetic resonance imaging of the brain revealed equal numbers of ischemic deficits in the treatment groups.

Acute Disease↗