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PubMed2003

Challenges in using geographic information systems (GIS) to understand and control malaria in Indonesia.

Malaria is a mosquito-borne disease of global concern with 1.5 to 2.7 million people dying each year and many more suffering from it. In Indonesia, malaria is a major public health issue with around six million clinical cases and 700 deaths each year. Malaria is most prevalent in the developing countries of the world. Aid agencies have provided financial and technical assistance to malaria-prone countries in an effort to battle the disease. Over the past decade, the focus of some of this assistance has been in the provision of geographic information systems (GIS) hardware, software and training. In theory, GIS can be a very effective tool in combating malaria, however, in practice there have been a host of challenges to its successful use.This review is based, in part, on the literature but also on our experience working with the Indonesian Ministry of Health. The review identifies three broad problem areas. The first of these relates to data concerns. Without adequate data, GIS is not very useful. Specific problem areas include: accurate data on the disease and how it is reported; basic environmental data on vegetation, land uses, topography, rainfall, etc.; and demographic data on the movement of people. The second problem area involves technology - specifically computer hardware, GIS software and training. The third problem area concerns methods - assuming the previous data and technological problems have been resolved - how can GIS be used to improve our understanding of malaria? One of the main methodological tools is spatial statistical analysis, however, this is a newly developing field, is not easy to understand and suffers from the fact that there is no agreement on standard methods of analysis.The paper concludes with a discussion of strategies that can be used to overcome some of these problems. One of these strategies involves using ArcView GIS software in combination with ArcExplorer (a public domain program that can read ArcView files) to deal with the problem of needing multiple copies of GIS software. Another strategy involves the development of a self-paced training package that can be used to train individuals

Journal Article↗

PubMed2005

Single subject pharmacological-MRI (phMRI) study: modulation of brain activity of psoriatic arthritis pain by cyclooxygenase-2 inhibitor.

We use fMRI to examine brain activity for pain elicited by palpating joints in a single patient suffering from psoriatic arthritis. Changes in these responses are documented when the patient ingested a single dose of a selective cyclooxygenase-2 inhibitor (COX-2i). We show that mechanical stimulation of the painful joints exhibited a cortical activity pattern similar to that reported for acute pain, with activity primarily localized to the thalamus, insular, primary and secondary somatosensory cortices and the mid anterior cingulum. COX-2i resulted in significant decreased in reported pain intensity and in brain activity after 1 hour of administration. The anterior insula and SII correlated with pain intensity, however no central activation site for the drug was detected. We demonstrate the similarity of the activation pattern for palpating painful joints to brain activity in normal subjects in response to thermal painful stimuli, by performing a spatial conjunction analysis between these maps, where overlap is observed in the insula, thalamus, secondary somatosensory cortex, and anterior cingulate. The results demonstrate that one can study effects of pharmacological manipulations in a single subject where the brain activity for a clinical condition is delineated and its modulation by COX-2i demonstrated. This approach may have diagnostic and prognostic utility.

Adult↗

PubMed2005

Functional diversification of MYB23 and GL1 genes in trichome morphogenesis and initiation.

The functional diversification of duplicated genes is one of the driving forces in evolution. To understand the molecular mechanisms of gene diversification, we studied the functional relationship of the two Arabidopsis paralogous MYB-related genes GL1 and MYB23. We show that MYB23 controls trichome branching and trichome initiation at leaf edges. The latter is controlled redundantly together with GL1. We show that the two proteins are functionally equivalent during trichome initiation but not during trichome branching. RT-PCR and reporter construct analysis revealed spatial, temporal and genetic differences in transcriptional regulation of the GL1 and MYB23 genes. Presented data indicate that the diversification of GL1 and MYB23 gene functions occurred at the level of cis-regulatory sequences with respect to trichome initiation, and that, in parallel, the diversification with respect to regulation of trichome branching also involved changes in respective proteins.

Arabidopsis↗

PubMed2006

The problem of image interpretation in mammography: effects of lesion conspicuity on the visual search strategy of radiologists.

Radiologists make the decision to report or dismiss a possible cancer based not only on the finding itself, but also in the comparison with selected areas of the background. We examined the effects of fixating, for the first time, the location where the radiologist either reported the presence of a malignant mass or visually inspected the mass but did not report it, and the effects of pairing radiologists to read the same cases. Four experienced mammographers participated in this experiment. They read a set of 20 cases twice. Eye-position tracking was used to monitor the visual search behaviour of the observers. Spatial frequency analysis was used to determine the characteristics of the areas of the background fixated by the observers. Radiologists had more fixations in the cases where they agreed how to manage the lesion than when they disagreed. Correlation between the areas of the background sampled by the radiologists and an "average" representation of the background increased after the observers fixated for the first time a malignant mass that they reported. Fixating, for the first time, a location where the radiologist reports a malignant mass or a location containing a cancer that the radiologist visually inspects but decides not to report, has a significant effect on any further sampling of the background. Furthermore, care should be taken when pairing radiologists, because some observers showed such a similar visual search behaviour that not much would be gained by having them read the same cases.

Breast Neoplasms↗

PubMed2004

Patterns of ethnic, linguistic, and geographic heterogeneity of palmar interdigital ridge counts in the Indian subcontinent.

Published data on palmar interdigital ridge counts (a-b, b-c, and c-d) among 57 populations from the Indian subcontinent were analyzed with reference to ethnic, socioeconomic, linguistic, and geographic affiliations of the studied populations. The spatial autocorrelation analysis suggests significant correlation between dermatoglyphic and geographic distances. The congruence with the ethnic semblance of the groups is also apparent in the data, and, in fact, the multiresponse permutation procedure did suggest highly significant within-group homogeneity, confirming the biological validity of the social and ethnic criteria used in the analysis. The plots of populations on the first two principal components, accounting for 92% of the total variance, complement and support the results based on the other analyses, which show certain ethnic and geographic patterns. These findings can serve as baseline information for future studies on population variation in India, particularly studies based on molecular genetic markers, a trend that has already gained momentum.

Dermatoglyphics↗

PubMed2006

Bone material properties in trabecular bone from human iliac crest biopsies after 3- and 5-year treatment with risedronate.

UNLABELLED: Long-term effects of risedronate on bone mineral maturity/crystallinity and collagen cross-link ratio in triple iliac crest biopsies of osteoporotic women were evaluated. In this double-blinded study, 3- and 5-year treatment with risedronate arrested the tissue aging encountered in untreated osteoporosis and in osteoporosis treated with other antiresorptives. This effect may be contributing to risedronate's antifracture efficacy. INTRODUCTION: Risedronate is widely used in the treatment of osteoporosis. It reduces bone turnover, increases BMD, and decreases fracture risk. To date, there are no data available on the long-term effects of risedronate on bone material properties in humans. MATERIALS AND METHODS: Osteoporotic women enrolled in the VERT-NA trial received either risedronate (5 mg/day, orally) or placebo for up to 5 years. All subjects received calcium. They also received vitamin D supplementation if deficient at baseline. Triple iliac crest biopsies were collected from a subset of these subjects at baseline, 3 years, and 5 years. Mineral maturity/crystallinity and collagen cross-link ratio was measured in these biopsies using Fourier transform infrared imaging. RESULTS: Patients that received placebo exhibited increased mineral maturity/crystallinity and collagen cross-link ratio after 3 and 5 years compared with baseline values. On the contrary, patients that received risedronate retained baseline values in both bone material indices throughout. A more spatially detailed analysis revealed that this was achieved mainly through beneficial effects on active bone-forming areas. Surprisingly, patients that received risedronate achieved premenopausal values at bone-forming areas in both indices after 5 years of treatment. CONCLUSION: Long-term treatment with risedronate affects bone material properties (mineral maturity/crystallinity and collagen cross-link ratio) and arrests the tissue aging apparent in untreated osteoporosis. These changes at the material level of the bone matrix may contribute to risedronate's rapid and sustained antifracture efficacy in osteoporotic patients.

Biopsy↗

PubMed1988

Analysis of the development of spatial contrast sensitivity in monkey and human infants.

The development of spatial contrast sensitivity in human and monkey infants reveals changes in the properties of underlying contrast-detection mechanisms in the visual system. A reanalysis of published data shows that the development of the spatial contrast sensitivity function can be described satisfactorily by the simultaneous vertical and horizontal scaling of a template function whose shape on a log-log axis does not change during development. Because individuals differ in the point to which contrast sensitivity has developed at any particular time, the use of group-averaged data as a basis for estimating the course of the developmental process has two undesirable results. First, it provides estimates of spatial contrast sensitivity during development that do not reflect any individual's sensitivity. Second, it incorrectly suggests that the shape of the spatial contrast sensitivity function changes during development.

Aging↗

PubMed2006

Ixodes scapularis ticks collected by passive surveillance in Canada: analysis of geographic distribution and infection with Lyme borreliosis agent Borrelia burgdorferi.

Passive surveillance for the occurrence of the tick Ixodes scapularis Say (1821) and their infection with the Lyme borreliosis spirochaetes Borrelia burgdorferi s.l. has taken place in Canada since early 1990. Ticks have been submitted from members of the public, veterinarians, and medical practitioners to provincial, federal, and university laboratories for identification, and the data have been collated and B. burgdorferi detected at the National Microbiology Laboratory. The locations of collection of 2,319 submitted I. scapularis were mapped, and we investigated potential risk factors for I. scapularis occurrence (in Quebec as a case study) by using regression analysis and spatial statistics. Ticks were submitted from all provinces east of Alberta, most from areas where resident I. scapularis populations are unknown. Most were adult ticks and were collected in spring and autumn. In southern Québec, risk factors for tick occurrence were lower latitude and remote-sensed indices for land cover with woodland. B. burgdorferi infection, identified by conventional and molecular methods, was detected in 12.5% of 1,816 ticks, including 10.1% of the 256 ticks that were collected from humans and tested. Our study suggests that B. burgdorferi-infected I. scapularis can be found over a wide geographic range in Canada, although most may be adventitious ticks carried from endemic areas in the United States and Canada by migrating birds. The risk of Lyme borreliosis in Canada may therefore be mostly low but more geographically widespread than previously suspected.

Animals↗

PubMed2006

A new system for the analysis of thermal judgments: multipoint measurements of skin temperatures and temperature-related sensations and their joint visualization.

We report a new system for monitoring sensations of many body parts as well as comprehensively showing the distribution of overall skin temperature (T(sk)) and temperature-related sensations. The system consists of a console with 52 levers to report temperature-related sensations and software that facilitates the visualization of the distribution of T(sk) and temperature-related sensations by displaying them on a model of the human body. The system's utility was demonstrated with a physiological experiment involving three males and three females. They were exposed to step changes of ambient temperature from 23 degrees C to 33 degrees C. We measured T(sk) at 50 points, and the subjects concurrently provided estimates of local temperature sensation and thermal comfort/discomfort at 25 loci. This system greatly facilitates the perception and analysis of spatial relationships and differences in temperature and sensation in various areas of the body.

Adult↗

PubMed2006

Cardiovascular expression of the mouse WNK1 gene during development and adulthood revealed by a BAC reporter assay.

Large deletions in WNK1 are associated with inherited arterial hypertension. WNK1 encodes two types of protein: a kidney-specific isoform (KS-WNK1) lacking kinase activity and a ubiquitously expressed full-length isoform (L-WNK1) with serine threonine kinase activity. Disease is thought to result from hypermorphic mutations increasing the production of one or both isoforms. However, the pattern of L-WNK1 expression remains poorly characterized. We generated transgenic mice bearing a murine WNK1 BAC containing the nlacZ reporter gene for monitoring L-WNK1 expression during development and adulthood. We observed previously unsuspected early expression in the vessels and primitive heart during embryogenesis, consistent with the early death of WNK1(-/-) mice. The generalized cardiovascular expression observed in adulthood may also suggest a possible kidney-independent role in blood pressure regulation. The second unsuspected site of L-WNK1 expression was the granular layer and Purkinje cells of the cerebellum, suggesting a role in local ion balance or cell trafficking. In the kidney, discordance between endogenous L-WNK1 and transgene expression suggests that either cis-regulatory elements important for physiological renal expression lie outside the BAC sequence or that illegitimate interactions occur between promoters. Despite this limitation, this transgenic model is a potentially valuable tool for the analysis of spatial and temporal aspects of WNK1 expression and regulation.

Alternative Splicing↗

PubMed1999

Resource for temporal information processing in interval production.

The resource required to process temporal information in interval production was investigated. 12 undergraduates performed 4-sec. interval production and nontemporal tasks, the probe digit task and the missing digit task. Although both tasks required memory search and employed the same modality for input and for responding, the probe digit task required a phonological resource and the missing digit task required a spatial resource. Analysis showed that both concurrent nontemporal tasks caused interval productions to be longer, suggesting that the temporal processing required a resource which both tasks used commonly. This resource may be a general purpose, capacity-limited resource associated with a central executive function in working memory.

Adult↗

PubMed2001

Nature of perceptual encoding of hand positions according to subjects' perceptuomotor expertise.

We investigated whether the nature of the perceptual information encoded for the memorization of successive hand positions varied according to subjects' perceptuomotor expertise. The experimental task used perceptual conflicts, induced by prisms, between visual and proprioceptive afferences during the encoding of various static hand positions. Control subjects were compared with skilled fencers, whose expertise was derived from the optimization. required and developed with practice, of the perceptuomotor processes involved in movement control. The analysis of spatial errors observed in a remembered target location test indicated that control subjects were dependent on the use of static visual information for the encoding of hand positions, whereas skilled fencers were not. Results are discussed in the light of the role of expertise in sensory integration and perceptual dominance.

Adolescent↗

PubMed1998

Frequency analysis of the EEG during spatial selective attention.

In this study, we recorded the event-related potentials (ERPs) elicited by stimuli appearing at attended and unattended locations. The voltage amplitudes and latencies of the P1, N1, P2, N2 and P3 visual components showed statistically significant differences in the attended condition with respect to the unattended one. The power spectral density of the EEG following stimulus onset was calculated. The difference between the spectral densities of the attended and unattended conditions was computed. Statistically significant differences were found in the decrease of alpha (9-11 Hz) and the increase of beta (15-17 Hz) frequencies during the attention condition with respect to the unattended condition. These results suggest that the arrival of a visual stimulus during the attended condition generates a complex reorganization of neuronal activity in both time and frequency domains.

Adolescent↗

PubMed1995

Parsing surrounding space into regions.

Surrounding space is not inherently organized, but we tend to treat it as though it consisted of regions (e.g., front, back, right, and left). The current studies show that these conceptual regions have characteristics that reflect our typical interactions with space. Three experiments examined the relative sizes and resolutions of front, back, left, and right around oneself. Front, argued to be the most important horizontal region, was found to be (a) largest, (b) recalled with the greatest precision, and (c) described with the greatest degree pf detao. Our findings suggest that some of the characteristics of the category model proposed by Huttenlocher, Hedges, and Duncan (1991) regarding memory for pictured circular displays may be generalized to space around oneself. More broadly, our results support and extend the spatial framework analysis of representation of surrounding space (Franklin & Tversky, 1990).

Adult↗

PubMed1992

Deficits of reaching in subjects with left hemiparesis: a pilot study.

Therapy to restore functional movement of stroke patients is based on assumptions about the deficits that occur in motor control as a result of stroke. Success has been limited, perhaps as a result of insufficient information concerning the characteristics of movement after stroke. In this pilot study, the Waterloo Spatial Motion Analysis Recording Technique (WATSMART), an optoelectric motion analysis system, was used with surface electromyography to measure voluntary reaching in the impaired and unimpaired arms of 5 subjects with left hemiparesis. The ability to reach in a smooth coordinated way was significantly poorer in the impaired arms than in the unimpaired arms, for which scores were essentially normal. The patients were less able to activate the muscles of the impaired arm and, as a result, used a greater percentage of the maximum activity they could generate to complete the unresisted reaching task. The electromyographic differences between arms, however, did not reach significance. The results corroborate previous findings and show that movement deficits of particular patients can be diagnosed precisely with kinematic analysis and electromyography. If greater precision in diagnosis were available clinically, more effective therapy might be developed.

Acceleration↗

PubMed1999

[Afferent inhibition and functional properties of neurons in the vibrissae projection area of the cat somatosensory cortex].

The aim of this study was to investigate the role of inhibitory processes in S-1 cortex of cats. The inhibition was evoked by "natural" afferent stimulation of the fascial vibrissae. For this purpose, two neighboring vibrissae were sequentially stimulated by mechanical deflection; single unit activity was recorded simultaneously from the cortex. Results showed that conditioning by afferent stimulation significantly influenced the directional sensitivity of cortical neurons. These data and analysis of spatial pattern of stimulated vibrissa indicate that detector neurons could be quickly modified during sensory processing.

Afferent Pathways↗

PubMed2000

Vasculogenesis in the day 6.5 to 9.5 mouse embryo.

The process of vasculogenesis was characterized in the 6.5- to 9.5-day mouse embryo and in allantoic culture by analysis of spatial and temporal expression patterns of the endothelial or hematopoietic lineage-associated proteins, TAL1, Flk1, platelet/endothelial cell adhesion molecule (PECAM), CD34, VE-cadherin, and Tie2. The study establishes that: (1) TAL1 and Flk1 are coexpressed in isolated mesodermal cells that give rise to endothelial cells and thus can be defined as angioblasts; (2) hematopoietic cells of blood islands express TAL1, but not Flk1; (3) vasculogenesis in the embryo proper is initiated by mesoderm fated to give rise to the endocardium; (4) the maturation/morphogenesis of blood vessels can be defined in terms of a sequential pattern of expression in which TAL1 and Flk1 are expressed first followed by PECAM, CD34, VE-cadherin, and later Tie2; and (5) TAL1 expression is down-regulated in endothelial cells of mature vessels. (Blood. 2000;95:1671-1679)

Allantois↗

PubMed2000

Intravenous cereport (RMP-7) modifies topographic uptake profile of carboplatin within rat glioma and brain surrounding tumor, elevates platinum levels, and enhances survival.

Several experiments studied the effects of i.v. infusions of the bradykinin agonist, Cereport (RMP-7), on permeability of the blood-brain tumor barrier in rat gliomas. First, the ability of Cereport to increase uptake of two poorly blood-brain barrier-penetrating drugs (lypophilic paclitaxel and hydrophilic carboplatin) was directly compared to provide new information regarding the scope of delivery effects achieved with Cereport. Next, the increased uptake of platinum into tumor and brain surrounding tumor was shown to closely parallel that of radiolabeled carboplatin, confirming that delivery of a biologically active moiety is increased with Cereport. This study also demonstrated that the elevated tumor levels of platinum persisted for at least 2 h. The enhanced carboplatin uptake was then examined using a novel, high spatial resolution analysis of autoradiography. This revealed that the effects of Cereport were not uniform throughout the tumor, because it especially modified those areas normally impermeable to carboplatin. Finally, a range of i.v. Cereport doses (3.0 and 9.0 microg/kg) was tested in combination with carboplatin to determine whether increased survival might be achieved and to define the relationship between Cereport dose, plasma levels, uptake of carboplatin, and enhanced survival. Survival was enhanced only by the high dose of Cereport; the high dose also produced robust increases in carboplatin uptake and plasma concentrations of Cereport estimated to achieve the K(i), whereas the low dose did not. These data offer fundamental information regarding the effects of Cereport on delivery of chemotherapeutic agents to brain tumors and provide new insight into receptor-mediated permeability of the blood-brain tumor barrier.

Animals↗