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PubMed1992

[Evaluation of evoked potential or event-related potential mapping].

Strategies for the evaluation of EP and ERP maps are discussed. Spatial interpolation is presented. The reference does not change the landscape but the wave shapes, the baselines change the landscape but not the wave shapes. Electric strength of the map is assessed using Global Field Power, whereby non-ambivalent component latencies can be established. Map landscapes are compared using Global Dissimilarity. Maps are classified using extracted landscape descriptors: locations of minimal and maximal potential, locations of the centroids of the positive and negative map area, reduction to a three-dimensional model dipole source. Adaptive segmentation into echoes of stable landscape (functional microstates) based on landscape descriptors is discussed. Diagnostic and physiological-functional interpretation of the results ought to be distinguished.

Brain Mapping↗
PubMed1991

An evaluation of the polymerase chain reaction for detection of alpha-globin genes in the prenatal diagnosis of alpha zero-thalassaemia.

Homozygous alpha zero-thalassaemia results in the fatal disease Bart's hydrops foetalis and since 3-4% of Singaporeans carry the alpha-thalassaemia genes, prenatal diagnosis of thalassaemia is essential. The aim of this study was to establish the polymerase chain reaction (PCR), a method that enables selective amplification of the 136 base pair (bp) region within the alpha-globin gene cluster, as a routine test for the prenatal diagnosis of homozygous alpha zero-thalassaemia. Confirmation of PCR results was performed using DNA gene mapping and electrophoresis of cord blood. DNA was extracted from 24 chorionic villi samples and the presence of the alpha-globin genes was determined by PCR. The results showed that the optimal number of amplifications for accurate diagnosis was 50 cycles. Homozygous alpha zero-thalassaemia was detected in four foetuses and the pregnancies terminated. Confirmation of alpha zero-thalassaemia by DNA gene mapping and electrophoresis of cord blood showed absence of alpha-globin genes and only Hb Bart's respectively. The remaining 20 foetuses were correctly diagnosed as normal or possessing the alpha-thalassaemia trait. Using the PCR at less than 50 cycles of amplification (example 35 cycles), false positive results were obtained in 30% of cases. We conclude that DNA amplification using the PCR offers an accurate method of prenatal diagnosis of alpha zero-thalassaemia. Its advantages over the more establish gene mapping method include a more rapid analysis (three days compared with ten days by gene mapping) and the requirement of only minute amounts of DNA (1 microgram) for analysis. It is however, essential that the optimal number of amplification cycles be established so that false positive results may be avoided.

Chromosome Mapping↗
PubMed1990

[Tridimensional cartography of potentials recorded on the human scalp: I. Interpolation with tridimensional functions].

Human cerebral electrophysiological studies make an increasing use of mapping to represent potentials recorded on the scalp. In order to draw potential maps a projection on a plane of the recording electrodes is required. An interpolation of the values of points between electrodes must then be performed. We have compared three interpolation methods (surface splines, spherical splines and tridimensional interpolation functions). The last two methods are interesting because, avoiding one projection, they do not create map distortions. Statistical evaluation of the three methods, using a dipolar model, shows the overall superiority of the tridimensional interpolation.

Brain Mapping↗
PubMed1995

[Evaluation of allele frequency of the hypervariable locus D17S30 in a sample of populations of European origin from a number of Siberian regions].

Frequencies of alleles of the polymorphic locus D17S30 were estimated in a sample of 121 unrelated Siberian inhabitants of European origin. The main method of study was polymerase chain reaction (PCR). The consecutive use of two pairs of primers allowed increasing of the specificity and sensitivity of the amplification reaction. The results of this study may be of theoretical interest for studies in population genetics. They may also find practical application in forensic medical examination and in the diagnosis of some genetic abnormalities.

Alleles↗
PubMed1994

Topographic investigation of brain atrophy in parkinsonism-dementia complex of Guam: a comparison with Alzheimer's disease and progressive supranuclear palsy.

The topographic distribution of brain atrophy in nine patients with parkinsonism-dementia complex of Guam (Guam PDC) was evaluated quantitatively, and compared with that in six Japanese patients with Alzheimer's disease or senile dementia of Alzheimer type (AD), five Japanese patients with progressive supranuclear palsy (PSP), and nine Japanese control subjects. Characteristic features of Guam PDC were as follows: (1) severe atrophy of the frontal and temporal cortex with relative preservation of the white matter; (2) atrophy of the tectum, tegmentum and cerebral peduncle of the midbrain, and (3) atrophy of the tegmentum and base of the upper pons. In contrast, sectional areas of the tectum and cerebral peduncle of the midbrain were relatively well preserved in PSP, while in AD there was no significant atrophy in the brain stem.

Aged↗
PubMed1996

Improved method for study of chromosomes of chorionic villus samples.

Chorionic villus sampling (CVS) offers rapid prenatal diagnosis of chromosomal disorders. We evaluated four methods for chromosomal analysis of chorionic villi (three based on direct preparations and one on long-term culture) in order to define a method which would provide good quality metaphases in sufficient numbers. The direct culturing method using synchronisation and dissociation with dispase was as good as long-term culturing. The optimal period of gestation for study was 10-12 wk.

Chorionic Villi Sampling↗
PubMed1998

Developmental changes in human cerebellum: expression of intracellular calcium receptors, calcium-binding proteins, and phosphorylated and nonphosphorylated neurofilament protein.

Few recent data are available on the development of the precise projection maps of the cerebellar cortex in humans. To address this topic, we studied temporal and spatial distribution of several antigens involved in calcium (Ca)-dependent processes: the intracellular Ca receptors, inositol 1,4,5-trisphosphate receptor type 1 (IP3R1) and ryanodine receptor (RyR); the Ca-binding proteins, calbindin D-28k (CB), parvalbumin (PV), and synaptophysin; and phosphorylated (SMI 31) and nonphosphorylated (SMI 32) forms of neurofilament protein. All antigens were studied in the human cerebellum during intrauterine development. The results of this study show that immunocytochemical markers appeared in the following sequence: CB and both forms ofneurofilament protein were observed at 4-5 gestational weeks (g.w.), PV appeared in the external granular layer and in a few Purkinje cells at 11 g.w., a diffuse immunostaining for IP3R1 and synaptophysin were observed at 13 g.w., whereas RyR was observed at 17-18 g.w. From 24 g.w. on, Purkinje cells expressed all four examined markers of intracellular Ca signaling as well as two forms of neurofilament protein. At the same time, compartmentation of the Purkinje cell layer was detected with three intracellular Ca-signaling molecules (IP3R1, CB, and PV) and with SMI 32. These results indicate that the developmentally regulated expression of antigens studied here may play a role in establishing a highly regular organization of terminal fields in the human cerebellar cortex. Moreover, the initial expression of these antigens is correlated temporally with other developmental processes in the cerebellum, such as cellular maturation, revealed by the immunoreaction to cytoskeletal protein, and synaptogenesis, revealed by immunoreaction to synaptophysin.

Afferent Pathways↗
PubMedDate not supplied

A brain image database for structure/function analysis.

BACKGROUND AND PURPOSE: Lesion-deficit-based structure-function analysis has traditionally been empirical and nonquantitative. Our purpose was to establish a new brain image database (BRAID) that allows the statistical correlation of brain functional measures with anatomic lesions revealed by clinical brain images. METHODS: Data on 303 participants in the MR Feasibility Study of the Cardiovascular Health Study were tested for lesion/deficit correlations. Functional data were derived from a limited neurologic examination performed at the time of the MR examination. Image data included 3D lesion descriptions derived from the MR examinations by hand segmentation. MR images were normalized in-plane using local, linear Talairach normalization. A database was implemented to support spatial data structures and associated geometric and statistical operations. The database stored the segmented lesions, patient functional scores, and several anatomic atlases. Lesion-deficit association was sought by contingency testing (chi2-test) for every possible combination of each neurologic variable and each labeled atlas structure. Significant associations that confirmed accepted lesion-deficit relationships were sought. RESULTS: Two-hundred thirty-five infarctlike lesions in 117 subjects were viewed collectively after mapping into Talairach cartesian coordinates. Anatomic structures most strongly correlated with neurologic deficits tended to be situated in anatomically appropriate areas. For example, infarctlike lesions associated with visual field defects were correlated with structures in contralateral occipital structures, including the optic radiations and occipital gyri. CONCLUSION: Known lesion-deficit correlations can be established by a database using a standard coordinate system for representing spatial data and incorporating functional and structural data together with appropriate query mechanisms. Improvements and further applications of this methodology may provide a powerful technique for uncovering new structure-function relationships.

Brain↗
PubMed1989

Computers: the best friends a human genome ever had.

Mapping and sequencing the human genome will generate large amounts of data, which must be sorted, analyzed, and stored for rapid retrieval to complete this enormous task. Computers and their software programs provide the most important tool to the molecular biologist today. A discussion of current capabilities and future needs in computer hardware and software for the human genome project is the topic of this paper. The use of computer programs to generate restriction maps, manage clone libraries, manage sequence projects, and generate consensus sequences is presented. The use of computers to communicate useful information rapidly to scientific colleagues is also mentioned. The role of both GenBank and BIONET is central to the dissemination and analysis of sequence information. The capabilities of electronic communication worldwide for assisting this project is available on the BIONET National Computer Resource, using existing networks.

Base Sequence↗
PubMed2004

Effects of a menthol-based analgesic balm on pressor responses evoked from muscle afferents in cats.

OBJECTIVE: To evaluate changes in heart rate (HR) and mean arterial pressure (MAP) as indicators of changes in pressor response for muscle afferents after topical application of menthol (MEN)-based analgesic balm. ANIMALS: 11 decerebrate cats. PROCEDURE: Pressor responses were reflexively evoked by static contraction of hind limb muscles, which are caused by group III and IV afferents. Responses were monitored without interference from anesthesia or effects of higher brain function by the use of decerebrate cats. After obtaining baseline data, MEN analgesic balm (1.9%) was applied to the skin over contracting muscles of 1 hind limb in 6 cats; petrolatum was applied to 5 control cats. Muscle contractions were evoked every 10 minutes, alternating between hind limbs, for 120 minutes. Peak MAP and HR were analyzed. RESULTS: Peak MAP responses evoked by static muscle contraction for the ipsilateral hind limb were significantly attenuated 20 minutes after application, but approached baseline values 40 minutes after application. The pressor response was significantly decreased 20 minutes after application during the last 12 seconds of the stimulus, which was attributed to group IV afferents. There were no significant differences in HR responses. CONCLUSIONS AND CLINICAL RELEVANCE: Application of MEN analgesic balm to the skin over contracting muscles significantly decreased the pressor response to static muscle contractions. This suggests that topical application of MEN has effects on responses evoked from receptors located in muscles. The MEN analgesic balm appeared to attenuate the pressor response 20 minutes after application, but it was a short-term effect.

Administration, Topical↗
PubMed1991

Experimental and clinical studies of neonatal eeg mapping--methodical prerequisites and data interpretation.

To investigate whether the sampling theorem was fulfilled up to now in experimental and clinical EEG-mapping of neonates and to determine the "smearing effect" of EEG transmission by the leading media up to the skin, EEG-maps from 5 slightly anaesthetized term newborn piglets and 8 healthy human newborns were calculated. A spatial sampling rate of 1-2 cycles per cm is necessary for a sufficient reproduction of surface EEG topology in newborn piglets showing activity maxima within motor projection zones. In human neonates, 8-channel mapping gave insufficient results, whereas state and EEG pattern related 16-channel maps provided sufficiently constant, but not complete pattern. Simultaneous maps from epidural and epiossal, and epiossal, and surface recordings in newborn piglets showed only small "smearing" effects. We conclude, the more topical interpretation chances exist, like in neonates with smaller "smearing" effects of transmission media, the more complete uptake of original data for mapping is necessary. Up to now, it is done seldomly.

Animals↗
PubMed2005

Global priority setting for Cochrane systematic reviews of health promotion and public health research.

BACKGROUND: Systematic reviews of health promotion and public health interventions are increasingly being conducted to assist public policy decision making. Many intra-country initiatives have been established to conduct systematic reviews in their relevant public health areas. The Cochrane Collaboration, an international organisation established to conduct and publish systematic reviews of healthcare interventions, is committed to high quality reviews that are regularly updated, published electronically, and meeting the needs of the consumers. AIMS: To identify global priorities for Cochrane systematic reviews of public health topics. METHODS: Systematic reviews of public health interventions were identified and mapped against global health risks. Global health organisations were engaged and nominated policy-urgent titles, evidence based selection criteria were applied to set priorities. RESULTS: 26 priority systematic review titles were identified, addressing interventions such as community building activities, pre-natal and early infancy psychosocial outcomes, and improving the nutrition status of refugee and displaced populations. DISCUSSION: The 26 priority titles provide an opportunity for potential reviewers and indeed, the Cochrane Collaboration as a whole, to address the previously unmet needs of global health policy and research agencies.

Evidence-Based Medicine↗
PubMedDate not supplied

[An AIDS-related cognitive map in a sample of drug abusers in Buenos Aires City].

This paper is an approach to AIDS as a topic among a drug abusers sample of the city of Buenos Aires. Research was carried out on the basis of a qualitative methodology. In an attempt at surveying opinions and attitudes of such a sample as regards AIDS (i.e. subjects' cognitive map), 21 drug abusers from three different rehabilitation programs operating in the B.A. area were interviewed. On the basis of the research performed, the authors elaborate communication strategies among drug abusers that would be helpful for authorities engaged in AIDS prevention to adopt. To boost a strategy likely to break up the AIDS-drug association existing in the mind of many an abuser would be highly advisable so that a separation be settled between both representations, thus giving drug abusers a higher motivation for self-care practice.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Construction of Enterococcus faecalis pAD1 miniplasmids: identification of a minimal pheromone response regulatory region and evaluation of a novel pheromone-dependent growth inhibition.

Several pAD1 miniplasmids were constructed that consisted of all or a portion of the pAD1 EcoRI B fragment with pheromone-inducible "E region" lacZ transcriptional fusions. Miniplasmids containing the entire EcoRI B fragment (the "E miniplasmids") were found to regulate LacZ expression normally, indicating that sufficient information is present on this fragment to regulate a pheromone response. These plasmids also encoded normal replication functions. The E miniplasmids were further reduced by deleting a KpnI fragment. These "K miniplasmids" were able to perform most of the functions central to a pheromone response but failed to induce the fused transcripts to levels observed in the parental plasmids. This defect was found to be due to a pheromone-dependent growth inhibition of cells containing the K miniplasmids. Evidence indicated that this inhibition was due to transcriptional readthrough beyond the lacZ gene and into the putative replication region of the plasmid. Possible mechanisms of this inhibition as well as its potential usefulness in further examining the characteristics of the pheromone response are discussed.

Chromosome Mapping↗