bluuebunny/crossref_metadata_2025 huggingface dataset:
The glutamate transporters EAAT2 and EAAT3 mediate cysteine uptake in cortical neuron cultures
Authors: Chen Yongmei , Swanson Raymond A.
Published: March 2003

Cysteine availability is normally the rate‐limiting factor in glutathione synthesis. How neurons obtain cysteine from extracellular space is not well established. Here we used mouse cortical neuron cultures to examine the role of the excitatory amino acid transporters (EAATs) in neuronal cysteine uptake. The cultured neurons expressed both EAAT2 and EAAT3. Cysteine uptake was predominately (> 85%) Na+‐dependent, with an apparent Km of 37 μm. Cysteine uptake was reduced by the EAAT substratesl‐glutamate andl‐aspartate and by synthetic EAAT inhibitors. The non‐selective EAAT inhibitor threo‐β‐hydroxyaspartate had a significantly greater maximal inhibitory effect than did the EAAT2‐selective inhibitor, dihydrokainate, indicating uptake by both EAAT2 and EAAT3. Serine, a substrate of ASC uptake system, had negligible effects on cysteine uptake at 10‐fold excess concentrations. To assess the functional importance of EAAT‐mediated cysteine uptake in neuronal glutathione synthesis, cultures were treated with diethylmaleate to deplete glutathione, then incubated with cysteine in the presence or absence of EAAT inhibitors. Threo‐β‐benzyloxyaspartate and the non‐transportable inhibitor threo‐β‐hydroxyaspartate both inhibited the cysteine‐dependent glutathione synthesis. The findings suggest that neuronal EAAT activity can be a rate‐limiting step for neuronal glutathione synthesis and that the primary function of EAATs expressed by neuronsin vivomay be to transport cysteine.
Cellular and behavioural effects of the adenosine A2a receptor antagonist KW‐6002 in a rat model of l‐DOPA‐induced dyskinesia
Authors: Lundblad M. , Vaudano E. , Cenci M. A.
Published: March 2003

We have examined the ability of KW‐6002, an adenosine A2a antagonist, to modulate the dyskinetic effects of l‐DOPA in 6‐hydroxydopamine‐lesioned rats. In animals rendered dyskinetic by a previous course of l‐DOPA treatment, KW‐6002 did not elicit any abnormal involuntary movements on its own, but failed to reduce the severity of dyskinesia when coadministered with l‐DOPA. A second experiment was undertaken in order to study the effects of KW‐6002 in l‐DOPA‐naive rats. Thirty‐five animals were allotted to four groups to receive a 21‐day treatment with: (i) KW‐6002 (10 mg/kg/day); (ii) l‐DOPA (6 mg/kg/day) i.p.; (iii) KW‐6002 plus l‐DOPA (same doses as above) or (iv) vehicle. Chronic treatment with KW‐6002‐only produced a significant relief of motor disability in the rotarod test in the absence of any abnormal involuntary movements. Combined treatment with l‐DOPA and KW‐6002 improved rotarod performance to a significantly higher degree than did each of the two drugs alone. However, this combined treatment induced dyskinesia to about the same degree as did l‐DOPA alone. In situ hybridization histochemistry showed that KW‐6002 treatment alone caused an approximately 20% reduction in the striatal levels of preproenkephalin mRNA, whereas neither the coadministration of KW‐6002 and l‐DOPA nor l‐DOPA alone significantly altered the expression of this transcript in the dopamine‐denervated striatum. Either alone or in combination with l‐DOPA, KW‐6002 did not have any modulatory effect on prodynorphin mRNA expression or FosB/ΔFosB‐like immunoreactivity in the dopamine‐denervated striatum.

These results show that monotreatment with an adenosine A2a receptor antagonist can relieve motor disability without inducing behavioural and cellular signs of dyskinesia in rats with 6‐hydroxydopamine lesions. Cotreatment with KW‐6002 and l‐DOPA potentiates the therapeutic effect but not the dyskinesiogenic potential of the latter drug.
Well‐being, sense of coherence, and burnout in stroke victims and spouses during the first few months after stroke
Authors: Nilsson Imogene , Axelsson Karin , Gustafson Yngve , Lundman Berit , Norberg Astrid
Published: March 2003

Well‐being, sense of coherence, and burnout in stroke victims and spouses during the first few months after stroke

Ten stroke victims, who had recently suffered their first manifest stroke with lasting neurological symptoms, participated, together with their spouses, in a study aimed at elucidating the well‐being, sense of coherence (SOC), and burnout during the first few months after discharge.

The stroke victims had no substantial speech disturbances, and showed no evidence of significant cognitive impairment, signifying they were mildly to moderately impaired by their stroke. All subjects were investigated at 1 and 3 months after homecoming. The methods used in this study were open‐ended interviews with all research participants, performed at two different appointments, and three self‐reporting questionnaires: the well‐being measure (WM), the SOC scale, and the burnout measure (BM). The instruments suit each other well, broaden the picture of living with stroke and give an attuned comprehensive understanding. The most striking finding was the substantial differences in the results, both regarding the stroke victims and their spouses, clearly indicating the limited value current generalizations have. The results also pointed to considerable distress both in stroke victims and spouses, although individuals with a weak SOC clearly displayed more difficulties in coping with the situation and risk of burnout, than did those with a strong SOC.
A comparison of patient needs as ranked by patients and nurses
Authors: Hallström Inger , Elander Gunnel
Published: March 2003

A comparison of patient needs as ranked by patients and nurses

A group of patients (n=69) were asked to arrange the three most important of 10 groups of needs, identified by patients in a previous study, in order of priority from one to three. A group of nurses (n=89) were asked to arrange same groups of needs in order of priority from one to three according to how they believed patients would rank them. No significant differences were found between patients cared for at medical and at surgical wards or between nurses working at different departments. However, differences were found between the rankings of patients and nurses.
The relationship between coping strategies and family burden among relatives of admitted psychiatric patients
Authors: Östman Margareta , Hansson Lars
Published: March 2003

Relationship between coping strategies and family burden among relatives of admitted psychiatric patients

Coping strategies as assessed by a projective coping instrument, showed only a weak relationship to perceived family burden and participation in care among 78 close relatives of voluntarily and compulsorily admitted psychiatric patients in this study conducted in two psychiatric services in Sweden in 1997. The results rather indicate that problem solving coping strategies are used when the relatives are in situations amenable to change and that emotion‐focused coping strategies are used in situations that are chronic and unchangeable. Furthermore, no differences in coping strategies were found between the relatives and a Swedish normative sample.

No relationships were found between coping strategies and when the relative thought that the patient’s mental health had led to mental problems in the relative or if the relative experienced that the relationship with the patient had been negatively affected by the mental illness. The usefulness of coping instruments based on personality components in research on family burden is called into question, and a reconsideration of qualitative research methods is recommended.
The applicability of the Antonovsky Sense of Coherence Scale to a group of Pentecostalists
Authors: Langius  , Björvell
Published: March 2003

The applicability of the Antonovsky Sense of Coherence Scale to a group of Pentecostalists

A methodological issue concerning the Antonovsky of Sense of Coherence (SOC) scale was raised in an earlier study questioning the applicability of the scale in different populations, and among these the Pentecostalists. The question was raised when a group of Pentecostalists had had difficulties in filling in another scale intended to measure the SOC.

Therefore, the aim of this study was to test the applicability of the 29‐item Antonovsky SOC scale in a group of people (n=37) belonging to a church of the Pentecostal Movement and to compare the results with those of a randomized group (n=145) from a general population. The Pentecostalists filled in the scale with no obvious difficulties. No significant differences were found between the Pentecostal group and the group of a general population regarding the total SOC scale scores (mean 152, SD 16 and mean 151, SD 18, respectively). The applicability difficulties found in the earlier study, however using an other SOC scale, could not be confirmed in the present study.

To conclude, the Antonovsky SOC scale has so far not shown to have applicability weakness.
The baby was the focus of attention – first‐time parents’ experiences of their intimate relationship
Authors: Ahlborg Tone , Strandmark Margaretha
Published: March 2003

The baby was the focus of attention – first‐time parents’ experience of their intimate relationship

The purpose of this study was to describe the phenomenon of ‘first‐time parents’ intimate relationship’, to focus on their mental health, and the ability to support them professionally. Ten Swedish parents (five couples) were interviewed on two occasions, when the first baby was 6 and 18 months old, respectively. A descriptive phenomenological method was used. The findings show that the essence of the phenomenon is ‘The baby was the focus of attention’. This had different meanings for the couples, putting them in two categories. For the first category, the essence was that the baby was the focus of mutual concern, which implied a fostered relationship. The strain of parenthood in this category was mild. In the second category, the baby was focused on at the expense of the father, who felt rejected emotionally. This impaired the relationship and parenthood involved a severe strain. The way the spouses communicated differed between the two categories. This study shows that mental health can be affected, especially among first‐time fathers, and this could jeopardize the relationship and family health. An awareness of this fact is needed among the health professionals giving care to first‐time parents.
Incidence of violence towards staff caring for the elderly
Authors: Åström Sture , Bucht Gösta , Eisemann Martin , Norberg Astrid , Saveman Britt‐Inger
Published: March 2003

Incidence of violence towards staff caring for the elderly

A survey study concerning violence was conducted among staff (n=506) working with the elderly in residential settings and ordinary homes. The major aim of the study was to investigate the incidence of violence directed towards staff by elderly people living in residential settings. Furthermore, associations between the number of violent incidents and gender, age, year in service, year at present place of work, education of the staff, type of setting, the frequency and type of violence as well as the emotional reactions expressed by the staff should be examined. Forty percent of the staff was exposed to violence during the preceding year and 18% noted incidents of violence daily. A significantly larger proportion of staff working in nursing homes registered violence compared with those working in other types of settings. Physical violence was the most common (76%) type of violence. Powerlessness, sadness, anger and feelings of insufficiency were the most dominant feelings among staff facing by violent situations. Our results point to the necessity to further study caregivers' perception of patient violence and its impact on the quality of care.
Oral health and nutritional status in a group of geriatric rehabilitation patients
Authors: Andersson Pia , Westergren Albert , Karlsson Siv , Rahm Hallberg Ingalill , Renvert Stefan
Published: March 2003

Oral health and nutritional status in a group of geriatric rehabilitation patients

The aims of this study were to evaluate the oral health status and nutritional status in a group of geriatric rehabilitation patients, and to analyse the relationship between these two parameters. Nurses at the ward performed structured assessments of oral and nutritional status using the Revised Oral Assessment Guide and the Subjective Global Assessment form in 223 newly admitted patients. Most oral health problems were found among patients who stayed longer at the hospital and were more dependent on help as compared with the healthier patients. Thirty‐four per cent of the patients were either severely undernourished, at risk or suspected to be undernourished (UN). Oral health problems were more common among UN patients (p < 0.0005) compared with well‐nourished patients. The most frequent oral health problem was found on teeth or dentures (48%). Problems related to the tongue and lips were also common among UN patients (56 and 44%, respectively). Oral health status was correlated (r = 0.32) to nutritional status. Problems with swallowing had the strongest association to the nutritional status (OR 6.05; 95% CI 2.41–15.18). This study demonstrated that poor oral health status was related to undernourishment.
Advanced home care for cancer patients at the end of life: a qualitative study of hopes and expectations of family caregivers
Authors: Wennman‐Larsen Agneta , Tishelman Carol
Published: March 2003

Advanced home care for cancer patients at the end of life: a qualitative study of hopes and expectations of family caregivers

It is increasingly common that cancer patients are cared for at home at the end of life, with help from advanced home care teams. This may have positive implications for cancer patients and their families, but it may also be burdensome to the family caregivers with implications for their health and well‐being. This qualitative study was therefore initiated to prospectively explore how family caregivers reason about their expectations of providing end‐of‐life care at home for relatives with cancer, enrolled in advanced palliative home care units. Ten interviews were conducted with 11 family caregivers at enrolment to the home care unit. A form of constant comparative analysis was used to generate two main themes from the data. One theme concerned the role transition into becoming a family caregiver, whereas the other theme relates to the transition to a new life situation of the caregiver (him/herself). The family caregivers describe themselves as the persons primarily bearing responsibility and providing care for their dying relatives. They were found to have many concerns about their own situation, especially in regard to issues temporally after the death of the patient, but seemed to have few expected sources of support related to these concerns. Professional support is described as expected primarily for care‐related tasks, although hopes may be expressed about support in other areas. The distinction between resources described as existing in theory and those used in practice also are apparent in analysis of the interviews. If home care is to be a positive alternative to hospital care, individual expectations should be considered when planning supportive care.
Threats and violence in Swedish care and welfare – magnitude of the problem and impact on municipal personnel
Authors: Menckel Ewa , Viitasara Eija
Published: March 2003

The problem of threats and violence at work has received increasing attention in Sweden in recent years. Exposure is especially high among health‐care personnel in social services. A nationwide survey of prevalence, work environment and risk situations was conducted. A questionnaire was sent to a stratified sample of 2800 local government employees in the care and welfare sector, working mainly with the elderly or persons with developmental impairments. Seven occupational groups, including supervisors, specialists and other categories of carers, were included, and represented a population of more than 170 000 employees. The response rate was 85%. The results indicated that as many as 51% of the population had been affected by threats/violence, either verbally or physically, over the previous year. Moreover, the results suggest that over 9% of the employees in the care sector experienced acts of violence or threats on a daily basis, and several times a month by 67%. The most vulnerable groups were assistant nurses and direct carers. Verbal threats appear more common (79%), but 66% appear to have experienced physical assaults. Stratified estimates suggest that feelings of anger (41%) and helplessness (31%), but also minor physical injuries (18%), are frequent reactions. Organizational change in the workplace and high workload entailed increased risk. Threats and violence in health‐care settings are a major work‐environment issue. Greater knowledge of consequences for organization, work situation and health of personnel is needed.
Swedish parents of children with Down's syndrome
Authors: Hedov G. , Annerén G. , Wikblad K.
Published: March 2003

Becoming parents of a child with Down's syndrome (DS) challenges the adjustment ability in parenthood. Individuals with higher sense of coherence (SOC) are supposed to manage stressors better than those with lower SOC. The aims of this study were to investigate parental self‐perceived stress, SOC, frequency of gainful employment and amount of time spent on child care in Swedish DS parents (165 parents; 86 mothers, 79 fathers) and to compare those with control parents of healthy children (169 parents; 87 mothers, 82 fathers). The mean age of the children was 4.7 years. Parents responded to questionnaires separately including Hymovich's Parent Perception Inventory as stress measurement and Antonovsky's short version of the Orientation to Life. No differences concerning total employment rate were observed, but the DS mothers were more often employed part‐time than control mothers. The DS parents did not spend more time on child care than the control parents and they did not differ in mean SOC score, but the DS parents perceived greater stress. The differences in stress, particularly between the DS and control mothers, were related to time‐demanding areas. Parents with high SOC scores experienced significantly less self‐perceived stress.
Characterization of polymorphic microsatellite markers in a captive population of the eagle owl (Bubo bubo) used for supportive breeding
Authors: Isaksson M. , Tegelström H.
Published: March 2003

The Scandinavian eagle owl population decreased to a few hundred individuals during the first 80 years of the last century as a result of hunting, collecting of chicks, and reproductive problems because of pollution. When most threats against the population were gone, supportive breeding was initiated. Since then the population has recovered remarkably. We describe how seven polymorphic microsatellite markers (Bb‐42, 100, 101, 111, 126, 131 and 145) were developed from an enriched genomic library. These loci have three to 12 alleles and observed heterozygosities ranging from 0.20 to 0.94 in a sample of 66 individuals from a Swedish captive population.
Isolation of eight polymorphic microsatellite loci, using an enrichment protocol, in the phytopathogenic fungus Fusarium culmorum
Authors: Giraud T. , Fournier E. , Vautrin D. , Solignac M. , Vercken E. , Bakan B. , Brygoo Y.
Published: March 2003

We report the development of eight microsatellite markers in the haploid filamentous fungus Fusarium culmorum, a pathogen of numerous cereal crops. An enrichment protocol was used to isolate microsatellite loci, and polymorphism was explored with isolates of Fusarium culmorum and F. graminearum from natural populations collected from several French locations.
Isolation and characterization of seven tetranucleotide microsatellite loci in mungbean, Vigna radiata
Authors: Kumar S. V. , Tan S. G. , Quah S. C. , Yusoff K.
Published: March 2003

A simple and rapid method for isolating tetranucleotide microsatellites in mungbean, Vigna radiata, based on the 5′‐anchored polymerase chain reaction technique, revealed 15 microsatellite sequences. We report on the characterization of seven polymorphic microsatellite loci in V. radiata. The number of alleles per locus ranged from 2 to 6, whereas the observed heterozygosity ranged from 0 to 0.561. Tetranucleotide markers are useful because they amplify fewer stutter bands thus making scoring easier. These markers will be useful for detecting genetic variation in mungbean varieties for germplasm management and development of the crop.
Microsatellite markers for the Mexican spotted owl (Strix occidentalis lucida)
Authors: Thode Anna B. , Maltbie Mary , Hansen Leslie A. , Green Lance D. , Longmire Jonathan L.
Published: March 2003

A genomic cosmid library was used to develop seven highly polymorphic microsatellite markers for the Mexican spotted owl (Strix occidentalis lucida). These are the first reported microsatellite markers derived from this species. The cloned and sequenced repeat motifs include a triplet repeat of (AAT)n, two tetranucleotide repeats of (GATA)n, a tetranucleotide repeat of (ATCC)n, a compound repeat of (GA)n(GATA)n and the two pentanucleotide repeats (AGAAT)n and (ATTTT)n. The microsatellites described represent six presumably independent loci with the two pentanucleotide repeats having originated from a single cosmid. Primer pairs allow locus‐specific amplification of each marker from Mexican spotted owl genomic DNA.
Polymorphic microsatellite loci in the sponge Crambe crambe (Porifera: Poecilosclerida) and their variation in two distant populations
Authors: Duran S. , Pascual M. , Estoup A. , Turon X.
Published: March 2003

Seven polymorphic microsatellite loci were characterized in the marine encrusting sponge Crambe crambe from a partial genomic DNA‐enriched library. Preliminary data on allelic variation of these loci in two distant populations of C. crambe are presented to assess their potential utility as high‐resolution genetic markers for this species. The number of alleles per locus ranged between three and 16 and the distributions of allele frequencies differed considerably between the two populations, indicating a marked genetic differentiation between them. These are the first microsatellite loci reported from any species in the phylum.
Characterization of five microsatellite loci in the pine shoot beetle Tomicus piniperda (Coleoptera: Scolytidae)
Authors: Kerdelhué C. , Mondor‐Genson G. , Rasplus J.‐Y. , Robert A. , Lieutier F.
Published: March 2003

Tomicus piniperda is a bark beetle that causes damage to various pine species across a wide geographical range. We developed five microsatellite polymorphic markers using an enrichment protocol. All loci could be successfully amplified with no evidence of null alleles and will be useful for population genetic studies. Cross‐species amplifications show that at least some of the markers could be useful in four other Tomicus species.
The distribution and habitats of crossbills Loxia spp. in Britain, with special reference to the Scottish Crossbill Loxia scotica
Authors: Summers Ron W. , Jardine David C. , Marquiss Mick , Rae Robert
Published: March 2003

A study was carried out, primarily in northern Scotland, to relate bill and wing measurements to diagnostic calls of crossbill species, and thereby use the calls to describe the distributions and habitats of the different species. Bill depth and wing length measurements from museum specimens and live‐trapped birds were used to describe the size categories. Almost all measurements of crossbills from England were similar to measurements of Common Crossbills from Fennoscandia. Museum specimens showed that crossbills in northern Scotland between 1822 and 1990 were a combination of Common Crossbills, birds which were intermediate between Common and Parrot Crossbills (Scottish Crossbills), and perhaps a few Parrot Crossbills. However, catches of crossbills between 1995 and 2000 showed that Parrot Crossbills (based on bill and wing measurements) were present at some sites in the Highlands.

 Recordings of flight calls and excitement calls of birds of known bill sizes allowed a classification of crossbills according to call types. Four different flight calls (referred to here as types 1–4) and five excitement calls (types A–E) were recognized. A sample of small‐billed birds, thereby identified as Common Crossbills, indicated that there were three groups of Common Crossbills: those giving type 1 flight calls and type A excitement calls (1A), type 2 flight calls and type B excitement calls (2B), and type 4 flight calls and type E excitement calls (4E). Large‐billed birds identified as Parrot Crossbills gave mainly type 2 flight calls and type D excitement calls. Birds with intermediate bill depths (Scottish Crossbills) gave type 3 flight calls and type C excitement calls.

 Distributions based on calls showed that 1A Common Crossbills were widespread in Scotland but the other types of Common Crossbill were rare. Parrot Crossbills were found in a few localities in the Highlands, and Scottish Crossbills (defined as those giving type 3 flight calls and type C excitement calls) were restricted to the northern and eastern Highlands. Scottish Crossbills and 1A Common Crossbills had overlapping distributions, and overlapped greatly in the types of forests they used between January and March when the Scots Pine cones were still closed. However, Scottish Crossbills were more frequently associated with stands containing Scots Pine compared with Common Crossbills.
Costs and benefits of breeding in human‐altered landscapes for the Eagle Owl Bubo bubo
Authors: Marchesi Luigi , Sergio Fabrizio , Pedrini Paolo
Published: March 2003

We studied a population of 23–25 Eagle Owl Bubo bubo pairs between 1994 and 2000 in a 1330‐km2 study plot in the central‐eastern Italian Alps. Compared to random sites, territories were located at lower elevation and closer to intensively cultivated‐urbanized valley floors. Early laying was associated with low elevation and negatively affected productivity. Diet was dominated by rats, hedgehogs and dormice (n = 978 prey items), all of them typical of low‐elevation habitats. Higher productivity was associated with a higher proportion of rats in the diet of individual pairs. Low availability of rats resulted in a more diverse diet, in turn associated with low productivity. Territories were occupied every year in a non‐random fashion, and those most occupied were characterized by higher productivity and higher occurrence of the favoured prey types in the diet, suggesting they were of superior quality. Eagle Owls also paid a cost associated with nesting near human‐altered habitats: the main cause of mortality reported to local authorities was electrocution. This is an increasing cause of death for many European populations and may be a cause for conservation concern. Human persecution is also an important cause of mortality in some parts of the European range. Apart from such costs, the study population appeared to have adapted well to the proximity of humans: estimates of density and productivity were comparable to those recorded elsewhere in Europe. The pattern found in our population also held at higher spatial scales: data from 17 European populations showed density to be highest in low‐elevation, human‐altered landscapes.
Facility of accommodation in myopia
Authors: O'Leary Daniel J. , Allen Peter M.
Published: March 2003

Purpose: Myopes have been shown to have abnormal accommodative characteristics. This study investigated the characteristics of accommodation facility in myopic and emmetropic students.

Methods: Distance and near positive and negative accommodation response time components of facility were measured over a 1 min period using a −2.00 D/zero lens pair for distance responses and a ±2.00 D lens pair for near responses. 79 students (37 myopes and 42 emmetropes) aged 18–27 years acted as subjects. Subjects were masked, and the results were analysed in a masked fashion.

Results:
Mean distance facility was significantly lower (9.7 cycles per minute (cpm)) in the myopic group compared with the mean distance facility in the emmetropic group (15.6 cpm;
p <0.005). There was no significant difference in the near facilities of the two groups (11.5 cpm in myopes vs 12.9 cpm in emmetropes). Positive accommodation response time for distance vision was greater than 4 s in 45% of myopes and in 9% of emmetropes.

Conclusions: Our findings confirm that myopes tend to have abnormal accommodation responses to blur. Distance facility, but not near facility of accommodation is more frequently reduced in myopes than in emmetropes.
Sources of variability in the clinical photostress test
Authors: Margrain Tom H. , Thomson David
Published: March 2003

The photostress test is a simple clinical technique that can differentiate between retinal and post‐retinal disease. Unfortunately a wide range of normal results have been reported in the literature and it is perhaps for this reason that the test has been little used by clinicians. The purpose of this investigation was to evaluate the effect of photostress technique, age, ametropia, pupil size and acuity on photostress recovery time (PSRT) in normal subjects. Photostress recovery time was measured in 50 healthy subjects whose ages ranged from 21 to 69 using three clinically applicable techniques and a reference technique designed to bleach a consistent amount of photopigment. The agreement between each clinical technique and the reference technique was determined. Mean photostress recovery time differed for each of the techniques studied. Analysis of the data obtained with the reference and the best clinical technique showed that age was the only factor that had a significant effect on PSRT. The best clinical technique involves exposing the eye to the light from the direct ophthalmoscope for 30 s and measuring the time taken for acuity to return to within one line of pre‐bleach acuity. Photostress recovery time increases with age but is independent of pupil size, ametropia and visual acuity.
Application of linear regression to videokeratoscope data for tilted surfaces
Authors: Douthwaite William A.
Published: March 2003

Purpose: To investigate the use of linear regression analysis performed on the tabular data display of the EyeSys videokeratoscope (VK). When a radius squared vs distance squared scatterplot is produced from aspheric surface data the equivalent conic section can be deduced from the intercept and slope of the linear regression line. Non‐linear plots are often produced. Linear regression may then be applied in a number of ways.

Method: Topographical data derived from both the EyeSys VK and a computer model of the instrument were analysed by three methods of linear regression. The resultant apical radii, p‐values and predicted surface tilts were compared with known values.

Results: The three methods predict different surface characteristics whose errors were found to vary depending upon the asphericity of the surface and its tilt. Conclusions: Apical radius is most accurately predicted by linear regression method (1). Both p‐value and tilt are best predicted by averaging the radius and position data for corresponding points in each semi‐meridian before squaring the resultant points and performing linear regression (method 3).
Model of the optical system of the human eye during accommodation
Authors: Popiolek‐Masajada Agnieszka , Kasprzak Henryk
Published: March 2003

A model of the human eye with a gradient index crystalline lens is presented. The crystalline lens shape at different accommodation levels is described by a single function which is a combination of hyperbolic cosine functions and hyperbolic tangent functions. Using the experimental data published in the literature a model of the variations of the external lens shape was created. Formulae for the lens shape parameters and gradient index distribution for different accommodation levels are given.
Central corneal thickness in European (white) individuals, especially children and the elderly, and assessment of its possible importance in clinical measures of intra‐ocular pressure
Authors: Doughty Michael J. , Laiquzzaman Mohammed , Müller Andreas , Oblak Emil , Button Norman F.
Published: March 2003

Purpose: To ascertain the impact of central corneal thickness (CCT, as assessed by pachometry) and central corneal curvature (as assessed by keratometry) on clinical measures of intra‐ocular pressure (IOP, as assessed by tonometry), especially in the young and elderly.

Methods: Pachometry, keratometry and tonometry were carried out on three groups, namely children aged 5–15 years, adults aged 32–60 years, and elderly individuals aged between 61 and 82 years. For children, ultrasound pachometry was combined with non‐contact tonometry (NCT), specular microscopy was used with Perkins tonometry in the adults, and ultrasound pachometry was used with Perkins tonometry for the elderly. Central corneal curvature was assessed by keratometry.

Results: The average CCT in children was 0.529 ± 0.034 mm (n=104, ±S.D.), averaged 0.533 ± 0.033 in adults (n=75) and 0.527 ± 0.034 mm (n=91) in the elderly. Tonometry values averaged 16.7 ± 2.9 mm in children, 13.0 ± 3.5 mmHg in adults and 13.6 ± 2.5 mm in the elderly group. Central corneal thickness values were not predictably different in relation to central corneal curvature values. Regression analyses indicated that the tonometry values were higher in both children and the elderly who had thicker corneas (and vice versa) (p ≤ 0.003), with the measures increasing by 1.3 ± 0.4 and 2.6 ± 0.4 mmHg for a 10% difference in CCT in children and the elderly, respectively. For adults, no statistically significant difference in tonometry values could be demonstrated with respect to CCT (<1 mmHg for a 10% difference in CCT), and for no group were the CCT or tonometry values predictably different in relation to central corneal curvature values.

Conclusions: The results of these studies, albeit relatively small scale, indicate that in young or elderly individuals with essentially normal IOP and CCT measures, the tonometry values show only small differences with respect to CCT. The slope in the observed relationship was not that different from an average of 1.5 mmHg for a 10% different in CCT, as obtained from a literature analysis over a 30‐year period. The magnitude of the effect does not provide evidence that pachometry needs to be routinely performed in glaucoma screening protocols based on tonometry. Notwithstanding, the finding of higher than expected tonometry values should be further investigated, by pachometry, especially in very young children and in the elderly.
Ultrasound biomicroscopy of the anterior segment of the enucleated chicken eye during accommodation
Authors: Choh Vivian , Sivak Jacob G. , Irving Elizabeth L. , Wong Winnie
Published: March 2003

Abstract Ultrasound biomicroscopy produces real‐time two‐dimensional images of ocular structures measured non‐invasively. Given recent work which shows that lenses from myopic eyes show shorter focal lengths and reduced accommodative amplitudes compared with controls, this study was undertaken to determine the structural characteristics of the anterior segment of chicken eyes during accommodation using the ultrasound biomicroscope (UBM). Form‐deprivation myopia and hyperopia were induced in hatching chicks by the application of either translucent or +15 D defocus goggles. After 7 days, eyes were enucleated and ultrasound biomicrographs of the eye, at rest and during ciliary nerve‐stimulated accommodation, were collected. For all eyes, accommodation was associated with a decrease in anterior chamber depth, an increase in lenticular thickness and a steepening of the front lenticular surface curvature. Changes related to refractive error were more difficult to detect. Myopic eyes showed deeper anterior chamber depths and differences in lenticular thicknesses just above the resolution limit for detection. In +15 D lens‐treated eyes, anterior chamber differences were opposite but smaller, just at the limit of resolution, while differences in mean lenticular thickness were not resolvable at a pixel or above. The UBM is a good tool for measuring robust changes during accommodation, but is limited in its ability to detect subtle changes associated with experimentally induced ametropias.
The use of video refraction to measure the dynamic properties of the near triad in observers of a 3‐D display
Authors: Ukai Kazuhiko , Kato Yumi
Published: March 2003

Abstract Objective: Recording of the dynamic behaviour of the near triad during viewing of a three‐dimensional (3‐D) display is attempted. This may then be used to identify the possible origin of asthenopia and other ocular problems which occur whilst viewing such displays.

Methods: Subjects viewed a 3‐D display through an image splitter. Video recordings of ocular responses (pupil diameter, vergence and accommodation) were made with a commercially available video refraction unit at a distance of 1.2 m from the subject. Continuous recordings were made whilst a step‐wise disparity of up to 2.6° was introduced between the targets presented to the two eyes, but the accommodative stimulus remained unchanged. Image analysis from the recordings was carried out on a personal computer.

Results: Results showed various complex patterns of response, with the accommodation and vergence recorded reflecting the effect of stimulus conflict. Difficulty in fusional convergence was recorded when disparity was large, and the recordings reflected the subjects' comments.

Conclusion: The video refraction method is a useful tool for studying the dynamic behaviour of the near triad.
The effect of refractive blur on postural stability
Authors: Anand Vijay , Buckley John , Scally Andy , Elliott David B.
Published: March 2003

The effect of refractive blur upon postural stability was investigated under three conditions: normal standing, standing with input from the somatosensory system disrupted and standing with input from the somatosensory and vestibular systems disrupted. Standing stability was assessed using the centre of pressure (COP) signal from force plate data in four young subjects (mean 23.9 ± 3.1 years) and five repeated sets of measurements were taken. The subjects looked straight ahead at a horizontal and vertical square wave pattern of 2.5 cycles (degree)−1. Under each of the three test conditions, standing stability was measured with the optimal refractive correction and under binocular blur levels of 0, + 1, + 2, + 4, and + 8 D and with eyes closed. In the normal standing condition, dioptric blur had only a mild effect on postural stability. However refractive blur produced large increases in postural instability when input from one or both of the other two sensory systems were disrupted. We hypothesized that dioptric blur would have an even great effect on postural stability if the visual target used was of higher spatial frequency. This was confirmed by repeated measurements on one subject using a target of 8 cycles (degree)−1. The study highlights the possible importance of an optimal correction to postural stability, particular in situations (or people) where input from the somatosensory and/or vestibular systems are disrupted, and where the visual surrounds are of high spatial frequency.
Testing young infants with the Welch Allyn SureSight non‐cycloplegic autorefractor
Authors: Adams Russell J. , Dalton Susan M. , Murphy Angela M. , Hall Heather L. , Courage Mary L.
Published: March 2003

Both eyes of 74 healthy 2–12‐month‐old human infants were refracted twice with the new Welch Allyn SureSight non‐cycloplegic autorefractor. At least one reliable estimate of sphere and cylinder was obtained from both eyes of all babies attempted, and 88% of infants contributed two estimates from each eye. These measurements were collected in less than 2 min. Although spherical estimates changed little over the first year (mean = +1.78 D), cylindrical error appeared to decrease from a mean of about 1.4 D (at 6 months) to 0.9 D (at 12 months). Refractive estimates and variability agreed well with published infant data obtained with traditional cycloplegic retinoscopy. Repeatability was excellent for measurement of cylinder but for sphere, 17% of infants' estimates differed by at least 1.0 D between tests. However, given its simplicity and time‐efficiency, the SureSight should be a good candidate for the relatively easy screening of significant refractive error in non‐verbal paediatric patients.
Clinical performance of the Reichert AT550: a new non‐contact tonometer
Authors: Jorge J. , Díaz‐Rey J. A. , González‐Méijome J. M. , Almeida J. B. , Parafita M. A.
Published: March 2003

The aim of the present study was to assess the level of accuracy for measurements of intra‐ocular pressure (IOP) obtained with a new non‐contact tonometer (NCT) the Reichert AT550®. Measurements were compared against those obtained with the Reichert Xpert Plus, Goldmann applanation tonometer and Perkins tonometer. Thirty‐five university students were assessed with the four tonometers in a randomised order, with non‐contact tonometry performed first. Each of the four measurement devices had its own trained clinical observer. Plots of differences of IOP as a function of the mean for each pair of instruments were obtained. No statistically significant differences were found when comparing the AT550® NCT with contact applanation tonometry (AT) (p > 0.05), displaying the closest level of agreement (as represented by the lowest mean difference and the narrowest confidence interval) with the Goldmann tonometer (limits of agreement, 0.12 ± 2.17). In conclusion, readings of IOP with the AT550® NCT are clinically comparable with those obtained with Goldmann tonometry in a population with IOP within the normal range.
The Impact of Nutritional Needs of Older Adults on Recommended Food Intakes
Authors: Russell Robert M. , Rasmussen Helen , Fada
Published: March 2003

Abstract The elderly are at greater risk for nutrient deficiencies than are younger people. The complications of chronic disease states that are more common among older adults as well as the limitations that accompany the natural aging process can affect nutrient intake, absorption, and utilization. This paper reviews those nutrients for which research has been conducted among elderly populations to determine their specific needs. Based on the state of knowledge to date, recommendations are made. In addition, a modified food pyramid that takes into account the lower energy intakes and special nutrient needs of the elderly has been designed and is described here. Nutrient‐dense foods, adequate fluid and fiber, and supplementation of calcium, vitamin D, and vitamin B12 are each emphasized in this narrower version of the Food Guide Pyramid for seniors over age 70. Specific food choices that will help elderly people meet their changing needs and avoid nutrient deficiencies, such as fortified cereals, brightly colored vegetables and fruits, and low‐fat dairy products, are highlighted as well.
Analysis of the acute and chronic wound environments: the role of proteases and their inhibitors
Authors: Trengove Naomi J. , Stacey Michael C. , Macauley Shawn , Bennett Neil , Gibson Jane , Burslem Frank , Murphy Gillian , Schultz Gregory
Published: March 2003

To assess the differences in proteolytic activity of acute and chronic wound environments, wound fluids were collected from acute surgical wounds (22 samples) and chronic wounds (25 samples) of various etiologies, including mixed vessel disease ulcers, decubiti and diabetic foot ulcers. Matrix metalloproteinase (MMP) activity measured using the Azocoll assay was significantly elevated by 30 fold in chronic wounds (median 22.8 μg MMP Eq/ml) compared to acute wounds (median 0.76 μg MMP Eq/ml) (p < 0.001). The addition of the matrix metalloproteinase inhibitor Illomostat decreased the matrix metalloproteinase activity by approximately 90% in all samples, confirming that the majority of the activity measured was due to matrix metalloproteinases. Gelatin zymograms indicated predominantly elevated matrix metalloproteinase‐9 with smaller elevations of matrix metalloproteinase‐2. In addition tissue inhibitor of metalloproteinase‐1 levels were analyzed in a small subset of acute and chronic wounds. When tissue inhibitor of metalloproteinase‐1 levels were compared to protease levels there was an inverse correlation (p = 0.02, r = – 0.78). In vitro degradation of epidermal growth factor was measured by addition of 125I labelled epidermal growth factor to acute and chronic wound fluid samples. There was significantly higher degradation of epidermal growth factor in chronic wound fluid samples (mean 28.1%) compared to acute samples (mean 0.6%). This also correlated to the epidermal growth factor activity of these wound fluid samples (p < 0.001, r = 0.64). Additionally, the levels of proteases were assayed in wound fluid collected from 15 venous leg ulcers during a nonhealing and healing phase using a unique model of chronic wound healing in humans. Patients with nonhealing venous leg ulcers were admitted to the hospital for bed rest and wound fluid samples were collected on admission (nonhealing phase) and after 2 weeks (healing phase) when the ulcers had begun to heal as evidenced by a reduction in size (median 12%). These data showed that the elevated levels of matrix metalloproteinase activity decreased significantly as healing occurs in chronic leg ulcers (p < 0.01). This parallels the processes observed in normally healing acute wounds. This data also supports the case for the addition of protease inhibitors in chronic wounds in conjunction with any treatments using growth factors.
The fate of collagen implants in tissue defects
Authors: Bailey Allen J
Published: March 2003

The fate of collagen implants in a wound environment is determined by the host response they elicit, their accomodation for cellular infiltration and their susceptibility to proteolytic attack. Glutaraldehyde cross‐linking is most effective in delaying resorption and reducing an antibody response. The proteolytic events reflect the sequence of cellular infiltration of inflammatory cells during the proliferative phase of repair. The fibrous collagen implant is initially degraded by matrix metalloproteinase‐1 cleaving the triple helix into 3/4 and 1/4 helical fragments and by cathepsin cleavage of the telopeptide region of the collagen molecule containing the intermolecular cross‐links. The resulting triple helical fragments denature at physiological temperature and the resulting gelatin is rapidly degraded to amino acids by many proteases, primarily the gelatinases (matrix metalloproteinase‐2 and ‐9) and the cathepsins. A proportion of the fiber fragments are phagocytosed and digested intracellularly by cathepsins within the lysosomes. The collagen implant is ultimately degraded to its constituent amino acids, which like all other protein metabolic products may be re‐utilized. The post‐translational products, hydroxyproline and hydroxylysine and the various cross‐linking amino acids are excreted.