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Biomedical subjects

J Nicholson

Publications and source records attributed to J Nicholson.

At least 19 recordsLinked to original sources

Laboratory science and public health at CDC.

Laboratory technology is as essential to public health practitioners for monitoring threats to public health as it is to clinical practitioners who depend on laboratory technology to diagnose and monitor disease in individuals. Laboratory technology provides essential information for effective public health interventions, whether monitoring emerging infectious diseases, such as avian influenza globally; identifying pathogens, such as Escherichia coli in the U.S. food supply and pinpointing its source; screening newborns for devastating disorders, such as phenylketonuria, that can be prevented by early intervention; or developing the capacity to quickly screen for exposure to chemical and biologic agents.

Centers for Disease Control and Prevention, U.S.↗

Genetic evidence for a family-based Scandinavian settlement of Shetland and Orkney during the Viking periods.

The Viking age witnessed the expansion of Scandinavian invaders across much of northwestern Europe. While Scandinavian settlements had an enduring cultural impact on North Atlantic populations, the nature and extent of their genetic legacy in places such as Shetland and Orkney is not clear. In order to explore this question further, we have made an extensive survey of both Y-chromosomal and mitochondrial DNA (mtDNA) variation in the North Atlantic region. Our findings indicate an overall Scandinavian ancestry of approximately 44% for Shetland and approximately 30% for Orkney, with approximately equal contributions from Scandinavian male and female subjects in both cases. This contrasts with the situation for the Western Isles, where the overall Scandinavian ancestry is less ( approximately 15%) and where there is a disproportionately high contribution from Scandinavian males. In line with previous studies, we find that Iceland exhibits both the greatest overall amount of Scandinavian ancestry (55%) and the greatest discrepancy between Scandinavian male and female components. Our results suggest that while areas close to Scandinavia, such as Orkney and Shetland, may have been settled primarily by Scandinavian family groups, lone Scandinavian males, who later established families with female subjects from the British Isles, may have been prominent in areas more distant from their homeland.

Chromosomes, Human, Y↗

Botulinum toxin for cerebral palsy; where are we now?

In this article, the evidence base for botulinum-A treatment acquired in recent years is outlined, and the practicalities involved in providing this service are described. Botulinum-A is relatively new, and possible improvements for the future are considered.

Botulinum Toxins, Type A↗

Lateralized regular spatial patterns in oscillating drawing arm movements of right-handed young women.

There is a lacuna in literature with reference to the spatial lateral difference in fast rhythmical movements produced by the whole dominant and nondominant whole arm, where spinal regulation has a significant role. Based on a fast oscillating zigzag drawing task, this study focused on (a) creation of a specific model of the task based on the intermittencies of coupled vectors of the fast motion, (b) identification of the spatial patterns that triggered these vectors, and (c) identification of quantified lateral differences between the spatial rhythmical patterns. 12 strongly right-handed young women performed 9 to 11 trials drawing zigzag lines. Each participant was required to extend her arm and perform this task using the left and right arm selectively on a frontally positioned graphic design system. The spatial patterns produced on each trial were identified in terms of five constant combinations of horizontal (X) and vertical (Y) projections of each line on the zigzag drawings. The dominant arm differed from the nondominant arm in preferred patterns. Because the duration of each line in the zigzag was highly restricted in time, the appearance of the patterns with different block schemes of movement could be explained as being associated with lower levels of the central nervous system. Initiation of fast movement of the total upper arm is probably associated with selection of the block scheme of motor control appropriate to each arm. Each block scheme is grounded on the coupled vectors of motion organised with particular muscle groups. Some block schemes seemed linked specifically to the dominant arm.

Adult↗

A clinical evaluation of ophthalmic assessment in children with sensori-neural deafness.

BACKGROUND: Since 1991, children with sensori-neural deafness and their families within Southern Derbyshire have been supported by a multiagency approach to their diagnosis and management. RESULTS: One hundred and twenty-two children were seen at the Child Development Centre for an holistic assessment, and 110 of these children have had an ophthalmic assessment, of whom 48 (43.6%) were found to have ophthalmic abnormalities. These included 43 children (39.1%) with refractive errors, ranging from mild to severe. Of 82 children with uncomplicated deafness, 26 (31.7%) had refractive errors. The prevalence of ophthalmic problems was higher than the prevalence in hearing school children in the literature and in local pre-school children. There were six cases of Usher syndrome. Twenty-one children had more than one eye defect. The findings indicate that deaf and hearing impaired children are two to three times more likely to develop ophthalmic abnormalities than their hearing peers, which makes early detection of paramount importance. An important local outcome has been the establishment of guidelines for ophthalmic assessment to include assessment of vision and screening for Usher syndrome by electro-physiological testing at aged 7 years and above. Screening has been completed to date in 78 children with congenital sensori-neural deafness. CONCLUSIONS: Sensitive and efficient ophthalmic assessment and management are essential for all deaf and hearing impaired children and national guidelines need to be established for both assessment of vision and screening for Usher syndrome, based on further evaluated research.

Child↗

Are temporal characteristics of fast repetitive oscillating movement invariant?

Validation of the proportional duration model was attempted using very fast single-joint repetitive horizontal abductive-adductive movements of the stretched upper extremity with minimal cognitive input. Participants drew oscillating horizontal lines during 20 sec. over relatively short distances as quickly as possible without visual feedback. Spatial, temporal, and kinetic parameters were analysed. The amplitude and the time spent accelerating, decelerating, and reversing in both directions of each experimental line were recorded and related to the centre of gravity of the upper extremity. The accelerations of the centre of mass of the upper extremity were calculated and used to calculate the forces involved. The ratios of durations were compared and intercorrelated for the two fastest, two average, and two slowest cycles from each participant. Results exhibited significant standard deviations and variability of temporal and kinetic parameters within individual trials. The number of significant coefficients of correlation within individual trials was small despite the controlling influence of the same generalised motor program. The proportional duration model did not hold for our data. Peripheral factors (probably the length-tension relationship rule for skeletal muscles and viscosity of muscle) may be important in this type of action.

Biomechanical Phenomena↗

Genetic abnormalities detected in ependymomas by comparative genomic hybridisation.

Using comparative genomic hybridisation, we have analysed genetic imbalance in a series of 86 ependymomas from children and adults. Tumours were derived from intracranial and spinal sites, and classified histologically as classic, anaplastic or myxopapillary. Ependymomas showing a balanced profile were significantly (P<0.0005) more frequent in children than adults. Profiles suggesting intermediate ploidy were common (44% of all tumours), and found more often (P<0.0005) in tumours from adults and the spinal region. Loss of 22q was the most common specific abnormality, occurring in 50% of spinal (medullary) ependymomas and 26% of tumours overall. Genetic profiles combining loss of 22q with other specific abnormalities--gain of 1q, loss of 6q, loss of 10q/10, loss of 13, loss of 14q/14--varied according to site and histology. In particular, we showed that classic ependymomas from within the cranium and spine have distinct genetic profiles. Classic and anaplastic ependymomas with gain of 1q tended to occur in the posterior fossa of children and to behave aggressively. Our extensive data on ependymomas demonstrate significant associations between genetic aberrations and clinicopathological variables, and represent a starting point for further biological and clinical studies.

Adolescent↗

An evaluation of accelerated Portland cement as a restorative material.

Biocompatibility of two variants of accelerated Portland cement (APC) were investigated in vitro by observing the cytomorphology of SaOS-2 osteosarcoma cells in the presence of test materials and the effect of these materials on the expression of markers of bone remodelling. Glass ionomer cement (GIC), mineral trioxide aggregate (MTA) and unmodified Portland cement (RC) were used for comparison. A direct contact assay was undertaken in four samples of each test material, collected at 12, 24, 48 and 72 h. Cell morphology was observed using scanning electron microscopy (SEM) and scored. Culture media were collected for cytokine quantification using enzyme-linked immunosorbent assay (ELISA). On SEM evaluation, healthy SaOS-2 cells were found adhering onto the surfaces of APC variant, RC and MTA. In contrast, rounded and dying cells were observed on GIC. Using ELISA, levels of interleukin (IL)-1beta, IL-6, IL-18 and OC were significantly higher in APC variants compared with controls and GIC (p<0.01), but these levels of cytokines were not statistically significant compared with MTA. The results of this study provide evidence that both APC variants are non-toxic and may have potential to promote bone healing. Further development of APC is indicated to produce a viable dental restorative material and possibly a material for orthopaedic

Biocompatible Materials↗

Disability in children from different ethnic populations.

We report on the prevalence of severe neurodisability in children in the Southern Derbyshire Health Authority from different ethnic groups. Information was obtained from the health records of children at the Child Development Centre (CDC), and analysed according to ethnic group. There were 53 in the Pakistani group, 20 in the Indian group and 764 in a mixed group, of which 95% were of European origin. It was estimated that all children with severe disability in the area of the Health Authority had notes at the CDC, except for 10% of the mixed group living on the periphery. The numbers of children with different disabling conditions were recorded, together with a measure of the level of individual disability; the 'Disability Scores'. We also noted if the condition was genetic or chromosomal in origin. Pakistani children showed a higher prevalence than the other groups of severe learning disorder, severe and profound hearing loss and severe visual problems. They also had a slightly increased prevalence of autism and cerebral palsy. Conversely, they showed a lower prevalence of language disorder. Disability scores for Pakistani children attending the CDC were higher than for other groups. Genetic disease causing disability was 10 times more common in the Pakistani children than other ethnic groups. Disability is more common in Pakistani children probably as a result of the cultural practice of consanguineous marriages. This community needs special help for disabled children, and their families, for general support and appropriate genetic counselling.

Adolescent↗

Comprehensive genetic and histopathologic study reveals three types of neuroblastoma tumors.

PURPOSE: To determine the relationship between multiple genetic features, tumor morphology, and prognosis in neuroblastoma. PATIENTS AND METHODS: The genetic alterations and morphologic features that underpin three histopathologic risk classifications were analyzed in 108 neuroblastoma patients. Tumors were subdivided into four groups based on the three most frequent and prognostically significant genetic alterations (17q gain, 1p deletion, and MYCN amplification), and all other genetic, morphologic, and clinical data were analyzed with respect to these groups. RESULTS: Our analyses identify three nonoverlapping tumor types with distinct genetic and morphologic features, defined here as types 1, 2, and 3. Type 1 tumors show none of the three significant genetic alterations and have good prognosis. Both type 2 (17q gain only or 17q gain and 1p del) and type 3 (17q gain, 1p del, and MYCN amplification) tumors progress. However, these tumor types are distinguished clinically by having significantly different median age at diagnosis and median progression-free survival (PFS). Multivariate analysis indicates that 17q gain is the only independent prognostic factor among all genetic, histopathologic, and clinical factors analyzed. Among histopathologic risk systems, the International Neuroblastoma Pathology Classification was the best predictor of PFS. CONCLUSION: Our results indicate that specific combinations of genetic changes in neuroblastoma tumors contribute to distinct morphologic and clinical features. Furthermore, the identification of two genetically and morphologically distinct types of progressing tumors suggests that possibilities for different therapeutic regimens should be investigated.

Adolescent↗

Gain of 1q is associated with adverse outcome in favorable histology Wilms' tumors.

Although several genes/genetic loci involved in the etiology of Wilms' tumor have been identified, little is known of the molecular changes associated with relapse. We therefore undertook an analysis by comparative genomic hybridization (CGH) of 58 tumor samples of favorable histology Wilms' tumor taken at initial diagnosis and/or relapse. Tumors with anaplastic histology were excluded as this is known to be associated with p53 mutation and a poor prognosis. A control group of 21 Wilms' tumors that did not relapse was also analyzed. The overall frequency of gains or losses of genetic material detected by CGH was similar in both groups (77% in relapsing tumors and 70% in the nonrelapse group) as was the median number of changes per tumor (relapse group: n = 4, range, 1 to 19; nonrelapse group: n = 3, range, 1 to 8). However, gain of 1q was significantly more frequent in the relapse series [27 of 46 (59%) versus 5 of 21 (24%), P: = 0.019]. In 12 matched tumor pairs, the CGH profiles, including 1q gain, were similar at diagnosis and relapse, with little evidence for further copy number changes being involved in clonal evolution. The results suggest that 1q gain at diagnosis could be used to identify patients with favorable histology Wilms' tumor at increased risk of relapse who might benefit from early treatment intensification.

Chromosome Aberrations↗

A comparative clinical and histologic study of hair transplantation using Er:YAG, Er:YAG/CO2, and standard punch techniques.

BACKGROUND: This study compares the effects of Er:YAG laser alone, Er:YAG/CO2 laser at 5 W (low power), Er:YAG/CO2 at 10 W (high power), and standard punch techniques in 10 men with androgenetic alopecia. OBJECTIVE: To study the clinical and histologic features of hair transplantation with recipient graft defects created by a new hybrid Er:YAG and CO2 laser. METHODS: Ten male patients (mean age 34 y) with Norwood IV-VI androgenetic alopecia had hair replacement surgery with the recipient sites divided into four quadrants comparing cold stell, erbium, combined erbium low-power CO2, and combined erbium high-power CO2 technologies. Hair growth, intraoperative procedure, lateral thermal damage, and patient satisfaction were compared, utilizing each of the four stated technologies. RESULTS: The addition of CO2 laser at both low and high power settings resulted in improved hemostasis when compared with standard punch or Er:YAG laser alone. The mean hair counts were similar for the Er:YAG laser, Er:YAG/CO2 (5 W) laser, and standard punch at both 3 and 6 months after treatment. Lateral thermal damage was not significantly increased by the addition of low-power CO2 to Er:YAG. The addition of high-power CO2 (10 W) laser resulted in slightly lower mean hair counts at 3 months, but significantly decreased at 6 months (P =.05). Also, high-power CO2 laser caused significantly increased lateral damage. There were no detectable differences in hsp70 expression among the groups. CONCLUSION: The addition of 5 W CO2 laser to Er:YAG laser results in better hemostasis than Er:YAG laser alone, while not significantly diminishing mean hair counts or inducing increased lateral thermal damage.

Adult↗

Lateral difference in reaction times to lateralized auditory stimuli.

Evidence suggests that Reaction time (RT) is affected by human behaviour in that stimuli are processed and conducted faster and more accurately when they are presented directly to the specialised hemisphere and responded to more quickly when stimulus and response are mediated by the same hemisphere. The purpose of the current study was to investigate the effect of laterality using one parameter-reaction time (RT) on ipsilateral reactions to monuaural latralized stimuli. Twenty-four undergraduate polytechnic students and 10 representative level Rugby players participated in the study by reacting unilaterally to single and choice RT using simple and complicated sensor motor reactions (SMR). Results Shorter reaction times by the dominant hand while testing simple and complicated audio SMR, without reference to sex and sport skills results have been explained in terms of specialisation of left hemisphere in different aspects of information processes mechanisms, geared towards programming of the movement.

Acoustic Stimulation↗

Clinical and pathophysiologic correlates of 1064-nm Nd:Yag laser treatment of reticular veins and venulectasias.

BACKGROUND: The goal of sclerotherapy, laser therapy, and intense pulsed-light therapy is to produce long-term, cosmetically significant elimination of disfiguring leg veins. This study examines the histologic and clinical effects of using a 1064-nm Nd:YAG laser system on lower extremity vessels. DESIGN: A single treatment using the following parameters: wavelength, 1064 nm (multiple synchronized pulsing); spot size, 6 mm; pulse duration, 14 milliseconds (single pulse); and fluence, 130 J/cm(2). SETTING: Private dermatology practice. PATIENTS: Thirteen women (mean age, 38.5 years) with blue venulectasia, 0.5 to 1.5 mm in diameter (class 2), and reticular veins, 1.5 to 3.0 mm in diameter (class 3), on the thighs. MAIN OUTCOME MEASURES: Examination of treated and untreated areas by 2 masked observers using macrophotography (1, 2, 3, and 6 months after treatment), Doppler, and optical chromatographic changes. Findings from three 2-mm punch biopsies from treated (immediately and 4 weeks after treatment) and untreated sites. Routine histologic examination; special stains (for elastic and connective tissue and for mucopolysaccharides); and immunohistochemical analysis for expression of the heat shock protein hsp70, tie2 (an endothelial cell-specific receptor tyrosine kinase), and transforming growth factors beta1 and beta2. RESULTS: Eight patients (62%) manifested 75% to 100% clearing of treated vessel surface area. Treated areas revealed perivascular hemorrhage, thrombi, fragmentation and homogenization of elastic fibers, and eosinophilia of vessel walls. Expression of hsp70 and transforming growth factor beta was increased in treated vessels. CONCLUSIONS: Our data confirm the effectiveness of 1064-nm Nd:YAG laser treatment in clearing dilated lower extremity veins, probably by heat-induced vessel damage and subsequent fibrosis. Maintenance of clearing was achieved for up to 6 months. However, the presence of recanalized thrombi in some of the specimens suggests the potential for long-term vessel reappearance.

Adult↗

Relationships between walk/run performance and cardiorespiratory fitness in adolescents who are overweight.

BACKGROUND AND PURPOSE: Little is known about the methods used to assess the physical fitness of adolescents who are overweight. We investigated the relationship between walk/run performance and cardiorespiratory fitness in adolescents who are overweight. SUBJECTS: Eight African-American adolescents (5 female, 3 male) and 10 Caucasian adolescents (5 female, 5 male) who were overweight (mean age=14.5 years, SD=2.0, range=12-17; mean body mass index [BMI]=42.9 kg/m2, SD=11.5) participated in this study. METHODS: Subjects performed a 12-minute walk/run test. The distances traveled at both 9 minutes (D9) and 12 minutes (D12) were recorded, and the distance traveled between 9 and 12 minutes (D9-12) was calculated. Subjects also completed a maximal cycle ergometry test, during which peak oxygen uptake (VO2peak), anaerobic threshold (AT), peak power (Wpeak), and power at the anaerobic threshold (WAT) were determined. Body composition was determined by air displacement plethysmography. RESULTS: The mean percentage of body fat was 48.6% (SD=5.3%, range=40.3%-60.4%). Percentage of body fat and BMI were each inversely related to D9, D12, and VO2peak (all P<.005). Peak oxygen uptake (r=.72, P=.0001), VO2peak/kg lean body mass (r=.60, P<.005), Wpeak (r=.88, P<.0001), and WAT (r=.72, P=.0007) were all related to D12, with greater r values than for D9. If D9-12was included in regression analyses, D9 did not account for additional variance in any of the cycle ergometry variables. DISCUSSION AND CONCLUSION: These results suggest that an easily obtained measurement of physical performance (distance traveled during a 12-minute walk/run test) is related to cardiorespiratory fitness and to body composition in adolescents who are overweight. The 12-minute walk/run distance is more predictive of cycle ergometry test results than the 9-minute distance.

Adolescent↗

Y-chromosomal diversity in Europe is clinal and influenced primarily by geography, rather than by language.

Clinal patterns of autosomal genetic diversity within Europe have been interpreted in previous studies in terms of a Neolithic demic diffusion model for the spread of agriculture; in contrast, studies using mtDNA have traced many founding lineages to the Paleolithic and have not shown strongly clinal variation. We have used 11 human Y-chromosomal biallelic polymorphisms, defining 10 haplogroups, to analyze a sample of 3,616 Y chromosomes belonging to 47 European and circum-European populations. Patterns of geographic differentiation are highly nonrandom, and, when they are assessed using spatial autocorrelation analysis, they show significant clines for five of six haplogroups analyzed. Clines for two haplogroups, representing 45% of the chromosomes, are continentwide and consistent with the demic diffusion hypothesis. Clines for three other haplogroups each have different foci and are more regionally restricted and are likely to reflect distinct population movements, including one from north of the Black Sea. Principal-components analysis suggests that populations are related primarily on the basis of geography, rather than on the basis of linguistic affinity. This is confirmed in Mantel tests, which show a strong and highly significant partial correlation between genetics and geography but a low, nonsignificant partial correlation between genetics and language. Genetic-barrier analysis also indicates the primacy of geography in the shaping of patterns of variation. These patterns retain a strong signal of expansion from the Near East but also suggest that the demographic history of Europe has been complex and influenced by other major population movements, as well as by linguistic and geographic heterogeneities and the effects of drift.

Africa, Northern↗