bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in growth in Sandwich Tern chicksSterna sandvicensisand the consequences for pre‐ and post‐fledging mortality
Authors: Stienen Eric W. M. , Brenninkmeijer Alex
Published: March 2003

Fitness consequences of variation in body mass growth and body condition were studied in a Sandwich TernSterna sandvicensiscolony on Griend, Dutch Wadden Sea, during 1990–2000. Body mass increment during the linear growth phase predicted nestling survival probabilities accurately. Chicks growing less than 8 g per day had low survival probabilities until fledging, but within a range of 8–11 g per day growth only small effects on chick survival were observed. Effects of slow growth on survival became obvious after about 10 days after hatching. Slow growing chicks reached a much lower fledging mass, whereas slow growth had only small effects on structural size at fledging. Body condition of the chicks was highly variable and had strong effects on survival until fledging. However, body condition during the nestling stage did not influence post‐fledging survival. Body condition at fledging had no effects on post‐fledging survival and did not affect final mass or body size. It is argued that low fledging mass can be overcome soon after fledging, as parents take their fledglings closer to the foraging areas, thereby avoiding high rates of kleptoparasitism by Black‐headed GullsLarus ridibundus.
Calculating census efficiency for river birds: a case study with the White‐throated Dipper Cinclus cinclus in the Pyrénées
Authors: D’Amico Frank , Hemery Georges
Published: March 2003

Using the binomial law we modelled field data to estimate the probability (p̂) of detecting pairs of breeding White‐throated Dippers, and the population size (N̂± confidence limits). The model was divided into two parts according to whether the actual size of the population under study was known or not; in the latter case the truncated binomial model was used. Dipper abundance data were collected from three 4‐km‐long river tracts in the Pyrénées (France) during the breeding seasons of different years. Goodness‐of‐fit tests indicated that the binomial model fitted the data well. For a given visit during the survey, the estimated probability of detecting any pair of Dippers if they were present was always high (0.63–0.94) and constant from year to year but not between sites. Estimations (N̂) of the size of the population provided by the binomial model were very close to that derived from mapping techniques. This study provides the first ever quantification of the number of visits required to detect birds on linear territories: three visits were necessary to detect the whole breeding population.
Sexual ornament size and breeding performance in female and male European Shags Phalacrocorax aristotelis
Authors: Daunt Francis , Monaghan Pat , Wanless Sarah , Harris Mike P.
Published: March 2003

Research into sexual selection and animal ornamentation has been largely directed at males in sexually dimorphic species. In contrast, there is relatively little empirical information on female ornamentation. Using the European Shag Phalacrocorax aristotelis, a species in which both sexes have an ornamental crest during pair formation, we investigated the evidence for (1) a correlation between crest size and breeding performance and (2) assortative pairing on crest size. Crest size appeared unrelated to age in either sex, though our sample of males did not include first‐time breeders. The year of study was one in which overall breeding performance at the colony was poor. Females that did not subsequently produce a clutch had significantly smaller crests during the courtship period than those that did, suggesting a link between ornament size and current condition. This relationship was also significant in males. Among those birds that did produce eggs, there was a significant relationship between ornament size and laying date, again significant in both sexes, with early breeders having larger crests. Early breeding is generally associated with relatively high breeding performance in European Shags. Given that both males and females contribute substantially to parental care and that there will be intrasexual differences in quality, choosiness is likely to be favoured in both sexes, and individuals were found to be paired assortatively with respect to crest size. Our results suggest that ornament size is related to state in European Shags, and thus may be involved in mate choice in both sexes.
Spring nocturnal migration of Reed Warblers Acrocephalus scirpaceus: departure, landing and body condition
Authors: Bolshakov Casimir , Bulyuk Victor , Chernetsov Nikita
Published: March 2003

Nocturnal migration of Reed Warblers Acrocephalus scirpaceus was studied by trapping with ‘high nets’ on the Courish Spit (Eastern Baltic) during spring 1998–2000. In spring, Reed Warblers left the stopover site between 45 and 240 min after sunset (median 84 min), although 85% of birds took off between 45 and 120 min after sunset. Birds did not arrive until the fifth hour after sunset; 67% of birds ended their nocturnal flights in the penultimate hour before sunrise, i.e. at dawn. At the moment of migratory departure, the average Reed Warbler body mass was 12.79 ± 0.66 g (n = 60). Average body mass of birds ending migratory flight was 11.69 ± 0.67 g (n = 18). The difference was highly significant. However, more than half of the birds completed migratory flights with a considerable fuel load, and some even had energy stores sufficient for a migratory flight on the next night. The spring migratory strategy of Reed Warblers over Central and Northern Europe probably includes a succession of short migratory flights (4–6 h) during several subsequent nights with 1‐day stopovers.
Characteristics of visual display units that may cause visual difficulties
Authors: Burns David H.
Published: March 2003

The physical characteristics of a visual display unit (VDU) are compared to those of paperwork, through a review of the literature. Certain display characteristics are shown to enhance visual performance using a VDU whilst others significantly decrease it when compared to using hard copy. Overall, display characteristics do not necessarily render VDU use more difficult than if doing similar visual tasks without using a VDU.
Effect of naturally occurring visual acuity differences between two eyes in stereoacuity
Authors: Lam Andrew K. C. , Chau Apries S. Y. , Lam W. Y. , Leung Gloria Y. O. , Man Becky S. H.
Published: March 2003

Stereoacuity was measured in 30 subjects with a naturally occurring visual acuity (VA) difference between the eyes. The stereoacuity was measured by a modified Howard's apparatus using the staircase method and VA was measured with log MAR charts. Stereoacuity was worse in subjects with a large VA difference between the two eyes; the correlation between stereoacuity and VA difference was significant (r = 0.76, P < 0.001). Neither the VA of the worse eye nor of the better eye contributed to the reduction in stereoacuity. The deterioration was more obvious if VA difference between the two eyes was one line or more (correlation coefficient, r = 0.88, P < 0.001). This study also reinforces the use of a 70% stereo‐threshold when attempt stereoacuity results to compare with other studies.
Repeatability of clinical measurements of the amplitude of accommodation
Authors: Rosenfield Mark , Cohen Andrea S.
Published: March 2003

In order to determine whether a significant change has occurred in a clinical parameter, it is essential to assess the repeatability of the measurement procedure. Accordingly, the present study has examined the repeatability of three techniques for evaluating the subjective amplitude of accommodation. Clinical amplitudes were determined using the push‐up, push‐down and minus lens procedures in 13 young individuals (mean age: 24.3 years) on five separate occasions. The standard deviation (SD) of the five examinations was calculated for each individual and the mean values for the population sample determined. The mean SDs for the push‐up, push‐down and minus lens techniques were equivalent, with 95% confidence limits of approximately 1.4 D being observed for all three procedures. Furthermore, the mean amplitude recorded using the push‐up technique was significantly higher than that observed for the other two procedures. It is concluded that a change of at least ± 1.50 D should be adopted as the minimum significant shift in amplitude of accommodation for this age group.
Morphometric analysis of the corneal endothelium
Authors: Jackson A. J. , Archer D. B.
Published: March 2003

Early developments in specular microscopy and quantitative corneal endothelial image analysis have resulted in the publication of material describing the morphometric appearance of the mosaic in health and disease. A broad range of morphometric parameters, including cell area, diameter, perimeter, form and shape, have been used to describe cellular appearances. In may cases the selection of parameters appears inappropriate and uncoordinated. In this study, the corneal endothelium of 300 normal, traumatised and pathological corneas was photographed using the Keeler Konan Pocklington specular microscope. The morphometric characteristics of endothelial cells were assessed using the Kontron Mop II semi‐automated image analysis system. Results indicate that cell density and mean cell area measurements provide the most useful indices of age‐related, post‐traumatic and pathological cell loss. Cell perimeter and cell diameter measurements add value in those cases where cellular migration occurs in response to trauma or localised cell loss. The quantification of intercellular cell area variability (polymegethism), and cell shape variability (pleomorphism), provides additional data on the effects of physiological stress. Cell form factors, which exhibit large intercellular variability, prove unhelpful when applied to global populations of cells. The authors conclude that in performing quantitative analysis of the corneal endothelium, specular microscopists should apply informed restraint when selecting parameters for morphometric analysis. The relative merits of a range of morphometric parameters are discussed.
Corneal sensitivity recovery after photorefractive keratectomy (PRK)
Authors: Murphy Paul J. , Corbett Melanie C. , O'Brart David P. S. , Verma Seema , Patel Sudi , Marshall John
Published: March 2003

Purpose: To establish the pattern of recovery of corneal sensitivity post‐PRK using a non‐invasive aesthesiometer.

Methods: Two studies were undertaken. (1) A longitudinal study monitoring the recovery of corneal sensitivity in 10 patients over one year, following a PRK correction of −6D/6mm (correction (D)/ablation diameter (mm)). (2) A transverse study examining corneal sensitivity one year postoperative on 68 patients who underwent various correction procedures: −3D/5mm (n = 16), −3D/6mm (n = 13), −6D/5mm (n = 14), −6D/6mm (n = 12) and −6D/Multizone (n = 13).

Results: (1) Corneal sensitivity showed an immediate drop at week 1 (P < 0.05), with a further decline at week 2 (P < 0.05). Sensitivity recovered slowly over the following months. (2) Corneal sensitivity was reduced in the PRK‐treated eyes when compared to normal non‐contact lens wearing eyes (P < 0.01). No specific procedures effect was found.

Conclusions 1. The pattern of sensitivity change occurring is: (a) an initial rapid drop, followed by: (b) a slow recovery over 1 years.

2. At one year, sensitivity is still below both normal and contact lens wear levels.

3. The extent of sensitivity loss is not influenced by the depth of ablation.
Ocular complications in young patients with insulin dependent diabetes
Authors: North R. V. , Farrell U. , Banford D. , Jones C. , Gregory J. , Butler G. , Owens D. R.
Published: March 2003

Purpose: To compare the visual functions of a group of young patients with insulin dependent diabetes mellitus (IDDM) to a control group, and identify those with retinopathy and assess the influence of metabolic control.

Methods: A group of IDDMs (aged 10–21 years), were examined for two years at the UHW (n = 123). Fundus photography and ophthalmoscopy were performed under mydriasis. Visual acuity, colour vision (desaturated D15), contrast sensitivity (Vistech VCTS 6500) and metabolic control were assessed. In a subgroup (n = 7), accommodation, macular threshold, central visual fields and dark adaptation were measured.

Results: IDDMs made significantly more errors with the desaturated D15 than the control group, and had higher macular thresholds and lower amplitudes of accommodation (P < 0.05). IDDMs with retinopathy had significantly poorer metabolic control (HbA1) than those without.

Conclusion: Colour vision differed significantly between IDDMs and the control group. Fifty‐two IDDMs exhibited diabetic retinopathy. The need for good metabolic control is demonstrated.
The reliability of subjective refraction
Authors: Strang Niall C. , Winn Barry , Gray Lyle S. , Pugh John R.
Published: March 2003

Purpose: In this study we investigate the accuracy of automated infrared autorefractors and determine whether spectacles can be prescribed on the basis of autorefractor results alone.

Method: Two hundred and sixty two subjects (age range 7–92 years), participated in the study. All subjects underwent a complete eye examination and had their prescription determined by six commercially‐available autorefractors. A subsample of 47 subjects were randomly allocated spectacles using either the optometrist's or the autorefractor prescription in a double‐blind protocol. Subjects wore each prescription for two weeks and completed an oral questionnaire following each session.

Results: All autorefractors showed a similar level of accuracy. The mean difference in one autorefractor between the sphere result and the subjective sphere was −0.03 DS (95% confidence limits ± 1.22 D). Cylindrical components revealed a smaller level of agreement. Autorefractor performance was not significantly affected by age or refractive error. The subjects who participated in the questionnaire preferred wearing the optometrist's prescription in 51% of cases and 21% of subjects were unable to adapt to wearing the autorefractor result.

Conclusions: There is little difference in the accuracy of the six autorefractors. However, the 95% confidence limits of the instruments are too large to allow spectacles to be prescribed directly from the results of automated refraction.
Theoretical predictions and experimental findings of visual deficits in glaucoma
Authors: Sahraie A. , Edgar D. F. , Barbur J. L.
Published: March 2003

Purpose: To investigate the motion and colour processing in normal subjects and in patients with primary open angle glaucoma, and to develop theoretical models in order to explain present findings and to understand the processes involved.

Methods: Movement processing was investigated using an optical motion projection system, capable of generating continuous motion of a single dot target with controlled speed, displacement and motion direction. Displacement and direction discrimination thresholds (i.e. target displacement at a constant speed needed for 75% probability of detection of motion or correct discrimination of its direction) were measured for both foveal and peripheral stimulus presentations and for a range of speeds. Colour vision was tested using a novel method which employs a random luminance modulation technique to mask out achromatic contrast changes and allowing detection of a spatially structured object based on the processing of chromatic signals only (Barbur et al. 1993).

Results: Changes in the parameters of the motion detection model (e.g., delay time and receptor regularity) that was developed to predict the experimental data in normal subjects also predicts an increase in displacement threshold and poorer sensitivity for discrimination of motion direction in glaucoma patients. The results obtained show that patients may report stimulus motion in 80% of presentations whilst performing at chance when required to discriminate the direction of motion. Chromatic discrimination ellipses measured for foveal stimulus presentations in glaucoma patients were often similar to those measured in normal subjects. In the periphery, however, much larger chromatic displacement thresholds were measured in all directions.

Conclusions: The technique used to measure the chromatic discrimination ellipses is sensitive to glaucomatous nerve damage and the results suggest a larger threshold elevation in the periphery than at the fovea. The motion model developed to explain performance in normal vision also predicts the experimental findings in glaucoma patients and may be used to predict degraded motion discrimination in patient groups with similar pathologies.
The flash VEP in term and preterm infants: effect of flash intensity and sleep state
Authors: Shepherd Ashley J. , Saunders Kathryn J. , McCulloch Daphne L.
Published: March 2003

Purpose: The flash visually evoked potential (VEP) may be a useful indicator of visual and/or neurological prognosis following premature birth. A range of flash intensities was used to investigate maturation of the visual pathway in preterm infants.

Methods: Subjects were a consecutive group of 20 healthy preterm infants born at under 35 weeks gestation (29–35 weeks). VEPs in response to two flash intensities were recorded at 3 days of age and at term age (ISCEV standard protocol). The infant's sleep state was recorded for each test.

Results: Flash VEPs were consistently recordable in preterm infants. The most prominent component was a simple negativity (N3) approximately 300 ms after the flash. Its position and amplitude were unaffected by flash intensity, state or age (ANOVA). By term age, the P2 was the prominent component of the flash VEP. Its amplitude increased significantly with flash intensity (P < 0.01 repeat measures ANOVA) but its latency was unaffected.

Conclusions: The flash VEP between 29 and 35 weeks gestation is relatively invariant and shows little or no effect of stimulus intensity. In contrast, flash VEPs in term age infants have a P2 component which reflects stimulus brightness and sleep state.

Funded by The Scottish Office, Department of Home and Health.
Reliability of low contrast letter charts in different viewing conditions
Authors: Pardham Shahina
Published: March 2003

Test‐retest scores were obtained under binocular, monocular and monocular in the presence of conditions from 20 healthy older patients using the Pelli‐Robson and Regan (96% and 11% contrast) charts. Data were analysed using two indices: coefficients of repeatability and intra‐class correlation coefficients. Coefficient of repeatability determines the 95% confidence limits for change. The Regan 96% contrast chart showed the highest reliability under all viewing conditions. Comparing the different viewing conditions, binocular viewing showed the smallest coefficient of repeatability and the highest intra‐class correlation. Monocular viewing in the presence of glare showed the largest coefficient of repeatability and the lowest intra‐class coefficient. The results demonstrate the need for measuring reliability criteria under the appropriate viewing conditions when determining whether a significant change has occurred, e.g. with monocular glare scores in cataract or binocular performance in amblyopia.
The use of Newton's rings for characterising ophthalmic lenses
Authors: Illueca C. , Vazquez C. , Hernández C. , Viqueira V.
Published: March 2003

The interference technique of Newton's Rings is widely used for the quality control of optical surfaces because the precision obtained with this method proves to be very satisfactory. The dimensions of the rings permits calculation of the radii of curvature of the analysed surfaces and deformation of the interference pattern can be utilised to calculate other parameters, such as astigmatism. We describe the study of progressive surfaces by means of this technique, whereby the analysis of the various points of the progressive corridor is made, and also include information on the power function for these lenses, as well as the addition and corridor length.
Tear break‐up time: clinical procedures and their effects
Authors: Cho Pauline , Leung Lawrence , Lam Ada , Choi Alex
Published: March 2003

Three successive (representative) values of fluorescein‐instillation TBUT (tear break‐up time) were obtained from a group of young Hong Kong (HK)‐Chinese. The median TBUT1, TBUT2 and TBUT3 were 3.2, 3.8 and 4.5 sec, respectively. Wilcoxon signed‐rank tests showed that TBUT1 was significantly different from TBUT2 and TBUT3, but there was no difference between TBUT2 and TBUT3. It is therefore important, when measuring the TBUT, to specify which TBUT value was taken as the representative TBUT. Fluorescein was reapplied about six min after the first application, and the TBUT value re‐determined (TBUTR). The median TBUTR was not significantly different from TBUT1. The subjects were requested to return another day and TBUT values (TBUTW) were determined, with the subjects opening their eyes as wide as possible, such that the palpebral aperture size was increased. The mean±SD normal palpebral aperture size was 10.0±1.3 mm, and the mean±SD palpebral aperture size with the eyes wide open was 11.4±1.5 mm. The median TBUTW (3.6 sec) was significantly longer than the median TBUT1 (3.0 sec), but this difference appeared to be due to the extremely long TBUTW of one subject; no significant difference was found between the median TBUTW (3.4 sec) and TBUT1 (2.8 sec) when data from this subject were excluded. There was no significant correlation between changes in palpebral size and TBUT value.
Sequential pattern‐onset, ‐reversal and ‐offset VEPs: comparison of effects of checksize
Authors: Shawkat Fatima S. , Kriss Anthony
Published: March 2003

The effects of checksize on individual components of half‐field pattern‐onset, ‐reversal and ‐offset VEPs were studied by presenting these three modes of stimulation sequentially in a single recording epoch so as to provide near identical recording and subject conditions. Components on the side of the scalp ipsilateral and contralateral to the stimulated half‐field were measured so as to separate the macular and paramacular contributions. Ten checksizes were used (6′–110′). MANOVA showed a significant effect of checksize: small checksizes enhanced onset ipsilateral CII and contralateral P105, as well as all ipsilateral reversal components and offset N85 component, suggesting they are reflecting macular function. Onset CI, and contralateral reversal N105 and offset N115 components increased in amplitude with increasing checksize, suggesting they are predominantly of paramacular origin. The morphology of the contralateral onset P105 component was checksize dependent: small checks (<35′) produced a sharply defined positivity (macular sub‐component), whereas larger checks produced a broadened/bifid waveform, suggesting the emergence of a later paramacular sub‐component.
Evaluation of the pinhole pupillometer
Authors: German Emma J. , Hurst Mark A. , Wood Diana
Published: March 2003

Evaluation of pupil diameter is used in many clinical and research fields to aid diagnosis of neurological disorders and to monitor pharmacological effects upon the eye. Methods used to determine pupillary diameter have evolved from simple scale measurements to much more complex systems, supposedly improving accuracy and repeatability. However, many techniques are restricted to the consulting room or research laboratory due to the size of the equipment, its cost, or the expertise required.

We have evaluated a portable pupillometer originally developed by Broca, capable of precise measurements on fixed, dilated pupils, that has the potential to be used by unsupervised patients. Luminance levels will still need to be controlled because, although luminance does not influence the mechanics of the pupillometer itself, it significantly affects the natural pupil. The pinhole size should ideally be 1.1 mm in diameter, since smaller pinholes underestimate and larger holes overestimate pupil size. The pupillometer also exhibited reasonable accuracy in fixed pupils dilated with tropicamide. Pupil measurements were overestimated by 0.5% using the 1.1 mm pinholes (insignificant if the pupil can be measured to the nearest 0.25 mm) and both intra‐ and inter‐visit repeatabilities were relatively good. The results from this study therefore indicate that the pinhole pupillometer may be of use in pupil research, since it facilitates more frequent pupillary measurements over much longer time intervals than are currently achievable.
The stenopaeic slit: an analytical expression to quantify its optical effects in front of an astigmatic eye
Authors: Escrivá L. Muñoz‐ , Furlan Walter D.
Published: March 2003

The stenopaeic slit is a trial case accessory used in subjective refraction, especially when high astigmatism is present. In spite of its simplicity, the effect of the slit when it is not oriented along one of the principal meridians of the examined eye is difficult to predict, even in terms of classical geometrical optics. In this paper, the optical principles of the slit are considered with full details in the theoretical framework of the dioptric power space. An analytical expression to obtain the residual refractive error when a stenopaeic slit is placed in front of an astigmatic eye at any orientation is deduced. In the light of these results, some aspects of the clinical procedure are discussed.
The gradient index and spherical aberration of the lens of the human eye
Authors: Smith George , Atchison David A.
Published: March 2003

We present equations for analysing the primary spherical aberration of the crystalline lens, both as a whole and of its contributing parts. We apply these equations to two examples of gradient index lenses. The spherical aberration of one lens is well outside that expected for real lenses, but that of the other is within this range. We assess the sensitivity of the aberration to changes in surface shape and gradient index distribution. The process is applicable to other models of the gradient index of the lens.
Accommodation and the Stiles–Crawford effect: theory and a case study
Authors: Kruger P. B. , López‐Gil N. , Stark L. R.
Published: March 2003

Purpose:
Fincham (The accommodation reflex and its stimulus.
Br. J. Ophthalmol.
35, 381–393) was the first to suggest that the Stiles–Crawford effect (Type I) might provide a stimulus for accommodation, but the possibility has not been investigated experimentally. The present paper outlines a theoretical basis for such a mechanism, and includes a case study on a subject with a nasally decentred Stiles–Crawford (S–C) function.

Methods: Accommodation to a monochromatic sine grating was monitored continuously with the natural S–C function intact, or with apodising filters imaged in the subject's pupil to neutralise, reverse or double the natural S–C function.

Results: Mean accommodative gain was not reduced significantly when the normal S–C function was either neutralised or reversed.

Conclusions: For the present subject, the average S–C effect does not mediate the accommodation response to defocus, but more subjects should be examined. Other methods by which directionally sensitive cone receptors could detect light vergence are discussed.
Free surface nickel in CE‐marked and non‐CE‐marked spectacle frames
Authors: Walsh G. , Mitchell J. W. C.
Published: March 2003

Three hundred and ninety‐five new frames were tested for evidence of nickel release using dimethylglyoxime and ammonia. For areas of CE‐marked frames in direct contact with the skin a considerable improvement was found over the previous such survey by the authors, carried out before the widespread introduction of CE marking. However, free nickel was found in 6.5% of CE‐marked metal frames (excluding titanium and titanium alloy) in such areas and a majority of half joints. Some titanium alloy frames also tested positive for nickel in areas in contact with the skin.
Visual acuity and the accuracy of the accommodative response
Authors: Subbaram Manoj V. , Bullimore Mark A.
Published: March 2003

Previous investigators have observed that some subjects show large amounts of accommodative lag. We hypothesized that less accurate accommodation might be associated with poorer visual acuity and/or smaller pupil sizes. Sixty subjects (30 emmetropes and 30 myopes) aged 20–30 years, participated. All had best‐corrected visual acuity of 6/6 or better [mean=−0.10 ± 0.07 logarithm of the minimum angle of resolution (logMAR)]. Subjects monocularly viewed reduced Bailey–Lovie charts through a +6.50 D Badal lens on a Canon R1 auto‐refractor. Visual acuity, accommodative response and pupil diameter were measured for 0, 2 and 4 D accommodative stimuli. For accommodation measurements (N=10) subjects were instructed to fixate the smallest letters that they could read. The mean accommodative response was +0.22 ± 0.28, +1.83 ± 0.23 and +3.71 ± 0.27 D for the 0, 2 and 4 D stimuli, respectively. The mean visual acuity was −0.06 ± 0.10, −0.11 ± 0.07 and −0.11 ± 0.07 logMAR for the 0, 2 and 4 D stimuli, respectively. Visual acuity for the 0 D stimulus was significantly poorer than for other conditions (p < 0.001) and associated with increased accommodative lead (p < 0.01). There was also an association between visual acuity and accommodative response (or lag) for the 4 D stimulus (p=0.002). The emmetropes showed significantly better visual acuity than the myopes (p=0.004). No significant difference was observed in the accommodative response between emmetropes and myopes. Pupil diameter was not associated with the accuracy of the accommodative response (p > 0.17). Increased accommodative lead (0 D stimulus) and accommodative lag (4 D stimulus) are associated with decreased visual acuity. Smaller pupil diameters are not associated with increased accommodative lag.
A statistical model of the aberration structure of normal, well‐corrected eyes
Authors: Thibos Larry N. , Bradley Arthur , Hong Xin
Published: March 2003

Abstract A statistical model of the wavefront aberration function of the normal, well‐corrected eye was constructed based on normative data from 200 eyes which show that, apart from spherical aberration, the higher‐order aberrations of the human eye tend to be randomly distributed about a mean value of zero. The vector of Zernike aberration coefficients describing the aberration function for any individual eye was modelled as a multivariate, Gaussian, random variable with known mean, variance and covariance. The model was verified by analysing the statistical properties of 1000 virtual eyes generated by the model. Potential applications of the model include computer simulation of individual variation in aberration structure, retinal image quality, visual performance, benefit of novel designs of ophthalmic lenses, or outcome of refractive surgery.
Nutritional and Medical Assessment and Management of Eating Disorders
Authors: Rock Cheryl L.
Published: March 2003

Patients with eating disorders have abnormal eating patterns and altered nutritional status, in addition to dysfunctional attitudes and perceptions regarding food and body weight. The prevalence of clinical eating disorders in the general population is estimated to be 0.5–1% for anorexia nervosa, 2% for bulimia nervosa, and 2% for binge eating disorder. Both genetic and environmental factors appear to contribute to the risk of developing an eating disorder, which is often perpetuated by poor nutritional status and chaotic eating patterns. Metabolic, nutritional, and clinical abnormalities in both anorexia nervosa and bulimia nervosa occur as a result of starvation and purging behaviors. The primary goal of nutrition intervention in anorexia nervosa is weight restoration, which is also a crucial factor in the prevention of irreversibly compromised bone density. The primary goal of nutritional management of bulimia nervosa is to normalize the patient's eating pattern, which is typically chaotic and characterized by an overall pattern of food rules, restrictions, or dieting, regularly interspersed with episodes of binge eating and purging. Patients with an eating disorder not otherwise specified can have serious eating problems that can adversely affect health status, and the management issues in these patients are similar to those in the patient with anorexia nervosa or bulimia nervosa. Results from long‐term outcome studies suggest that the majority of patients with eating disorders make a full recovery, despite the severity of the disturbances in eating patterns and nutritional status present at diagnosis.
The Effect of Alcohol on Blood Pressure
Authors: Suter Paolo M. , Vetter Wilhelm
Published: March 2003

The pathogenesis of hypertension, a major risk factor for cardiovascular disease, is multifactorial. Alcohol consumption has been identified as one important modulator of blood pressure; many epidemiological, clinical, and interventional studies have shown a linear relationship between alcohol intake and blood pressure. These studies have also found that the absolute amount of alcohol consumed is more significant than the beverage type; recent alcohol intake is more influential than past alcohol intake; the hypertensive effect of alcohol is more pronounced in frequent drinkers and in females; and upon cessation or reduction of alcohol intake, blood pressure declines. Many different mechanisms, including alcohol's effects on the central nervous system and the vessel wall, may be responsible; however, a single mechanism has yet to be identified. Any patient with resistant hypertension without secondary hypertension should reduce alcohol intake as a nonpharmacological strategy to lower blood pressure. Daily consumption should be avoided and the upper limit of alcohol intake in one day should be 20 g (0.7 fluid ounce) for women and 30 g (1 fluid ounce) for men. Whenever possible, alcohol should be consumed with food.
Mind/Body Medicine: An Introduction for the Generalist Physician and Nutritionist
Authors: Johnson Susan Slager , Kushner Robert F.
Published: March 2003

Scientific evidence from psychoneuroimmunology (PNI) is driving a paradigm shift from a model of biomedical medicine to a biopsychosocial/spiritual model of mind/body medicine. Mind/body medicine seeks to bring balance to all disparate aspects of mind, body, and spirit, thus strengthening patients' potential for total wellness. In this model, nutrition is viewed as one means of boosting the intrinsic capacity for preventing illness and attaining wellness. Accumulating evidence for links among stress, unhealthy lifestyles, and obesity support the use of mind/body therapies to counter negative effects of stress in the context of an overall approach to this condition. This paper discusses evidence and clinical applications for the healing potential of autogenic training, breathing practices, guided imagery, meditation, music therapy, and spirituality.
Clinical Implications of Vitamin B12 Deficiency in the Elderly
Authors: Russell Robert M. , Baik Hyun Wook
Published: March 2003

Abstract Vitamin B12 deficiency is a prevalent condition in the elderly. Depending on the diagnostic criteria used, more than 10% to 15% of people over the age of 60 are estimated to be deficient in vitamin B12.

Diagnosis can be problematic because vitamin B12 deficiency may present as neurological or mental‐status changes—which can be confused with symptoms of other age‐related neurological disorders—rather than as megaloblastic anemia. A higher folate intake, due to the fortification of flour with this B vitamin, can mask and/or precipitate the hematologic signs of vitamin B12 deficiency, potentially delaying diagnosis and treatment, and increasing the risk of irreversible neurological damage to elderly people with subtle vitamin B12 deficiency. This paper will discuss two conditions contributing to the high prevalence of vitamin B12 deficiency in the elderly, as well as approaches to its diagnosis and treatment.
Curcumin enhances wound healing in streptozotocin induced diabetic rats and genetically diabetic mice
Authors: Sidhu Gurmel S , Mani Haresh , Gaddipati Jaya P , Singh Anoop K , Seth Pankaj , Banaudha Krishna K , Patnaik Gyanendra K , Maheshwari Radha K
Published: March 2003

Tissue repair and wound healing are complex processes that involve inflammation, granulation and tissue remodeling. Interactions of different cells, extracellular matrix proteins and their receptors are involved in wound healing, and are mediated by cytokines and growth factors. Previous studies from our laboratory have shown that curcumin (diferuloylmethane), a natural product obtained from the rhizomes of Curcuma longa, enhanced cutaneous wound healing in rats and guinea pigs. In this study, we have evaluated the efficacy of curcumin treatment by oral and topical applications on impaired wound healing in diabetic rats and genetically diabetic mice using a full thickness cutaneous punch wound model. Wounds of animals treated with curcumin showed earlier re‐epithelialization, improved neovascularization, increased migration of various cells including dermal myofibroblasts, fibroblasts, and macrophages into the wound bed, and a higher collagen content. Immunohistochemical localization showed an increase in transforming growth factor‐β1 in curcumin‐treated wounds compared to controls. Enhanced transforming growth factor‐β1 mRNA expression in treated wounds was confirmed by in situ hybridization, and laser scan cytometry. A delay in the apoptosis patterns was seen in diabetic wounds compared to curcumin treated wounds as shown by terminal deoxynucleotidyl transferase–mediated deoxyuridyl triphosphate nick end labeling analysis. Curcumin was effective both orally and topically. These results show that curcumin enhanced wound repair in diabetic impaired healing, and could be developed as a pharmacological agent in such clinical settings.
Molecular and mechanistic validation of delayed healing rat wounds as a model for human chronic wounds
Authors: Chen Chin , Schultz Gregory S. , Bloch Melissa , Edwards Paul D. , Tebes Steve , Mast Bruce A.
Published: March 2003

The purpose of this study was to provide molecular and mechanistic evaluation of an ischemic wound model in rats to determine if it is a valid model for human chronic wounds. Compared to acute wounds, human chronic wounds contain markedly elevated levels of proinflammatory cytokines and matrix metalloproteinases, while matrix metalloproteinase inhibitors and growth factor activity are diminished. Accordingly, tissue from ischemic and normal rat wounds were analyzed for cytokine, proteases and growth factor levels. Dorsal full thickness punch wounds were created in rats using a reproducible template. The ischemic wound group (n = 10) had six uniformly placed wounds within a bipedicled dorsal flap. The control group (n = 10) had the same wounds created without elevation of a flap. On postwound days 3, 6 and 13 wounds were excised and analyzed. Protein levels for tumor necrosis factor‐α were determined with a rat‐specific enzyme‐linked immunosorbent assay, while mRNA was determined by RNase protection assay. Matrix metalloproteinases and serine protease detection was done using gelatin and casein zymography, respectively. Significant delay in healing was achieved in the ischemic group: 50% healing for control wounds was at 7 days and 11 days for ischemic wounds (p < 0.001). No significant differences between wound groups were found for interleukin‐1β, and mRNA for tumor necrosis factor‐α and interleukin‐1β. However, at day 13 ischemic wounds contained significantly more tumor necrosis factor‐α than controls and normal skin (586 ± 106 pg/biopsy vs. 79 ± 7 pg/biopsy vs. 52 ± 2 pg/biopsy; p < 0.001). Zymography showed substantially greater quantities of matrix metalloproteinase‐2, matrix metalloproteinase‐9, and serine proteases in ischemic wounds. This model of delayed healing in rats shares many of the key biochemical, molecular and mechanistic characteristics found in human chronic wounds, namely elevated tumor necrosis factor‐α and protease levels. As such, this model will likely prove to be useful in chronic wound research, particularly in developing novel therapeutics.
Epidermal growth factor and keratinocyte growth factor differentially regulate epidermal migration, growth, and differentiation
Authors: Gibbs Susan , Silva Pinto Anna Nubia , Murli Seema , Huber Marcel , Hohl Daniel , Ponec Maria
Published: March 2003

Various growth factors such as epidermal growth factor and keratinocyte growth factor have been reported to promote wound closure and epidermal regeneration. In the present study epidermis reconstructed on de‐epidermized dermis was used to investigate the effects of epidermal growth factor and keratinocyte growth factor on keratinocyte proliferation, migration and differentiation. Our results show that epidermal growth factor supplemented cultures share many of the features which are observed during regeneration of wounded epidermis: a thickening of the entire epidermis, an enhanced rate of proliferation and migration, and an increase in keratin 6, keratin 16, skin‐derived antileukoproteinase, involucrin and transglutaminase 1 expression. The increase in transglutaminase 1 protein is accompanied by an increase in the amount of active transglutaminase 1 enzyme. Surprisingly no increase in keratin 17 is observed. Prolonging the culture period for more than two weeks results in rapid senescence and aging of the cultures. In contrast, keratinocyte growth factor supplemented cultures have a tissue architecture that is similar to healthy native epidermis and remains unchanged for at least 4 weeks of air‐exposure. The rate of proliferation and the expression of keratins 6, 16 and 17, skin‐derived antileukoproteinase, involucrin and transglutaminase 1 is similar to that found in healthy epidermis and furthermore keratinocyte migration does not occur. When the culture medium is supplemented with a combination of keratinocyte growth factor and a low concentration of epidermal growth factor, skin‐derived antileukoproteinase, involucrin and keratins 6, 16 and 17 expression is similar to that found in cultures supplemented with keratinocyte growth factor alone and in healthy epidermis. Only high transglutaminase 1 expression remains similar to that observed in cultures supplemented with epidermal growth factor alone. Our results show that the regulation of keratinocyte growth, migration and differentiation depends on the availability of these growth factors. Epidermal growth factor may play a dominant early role in wound healing by stimulating keratinocyte proliferation and migration while keratinocyte growth factor may play a role later in the repair process by stabilizing epidermal turnover and barrier function.
Comparison and evaluation of gene therapy and epigenetic approaches for wound healing
Authors: Cutroneo Kenneth R
Published: March 2003

During the past decade considerable evidence has mounted concerning the importance of growth factors in the wound healing process both for cell replication and for stimulating reparative cells to synthesize and secrete extracellular matrix components. During normal wound healing the growth factor concentration has to be maintained at a certain level. If the growth factor concentration is too low, normal healing fails to occur. Whereas if the growth factor concentration is too high due to either over‐expression of the growth factor or too much growth factor being applied to the wound, aberrant wound healing will occur. One approach for controlling the amount of growth factor at the wound site during normal healing is through gene therapy and the titration of gene dosage. However if a narrow window exists between the beneficial therapeutic effect and toxic effects with increasing gene dosage, an agent may be necessary to give in combination with gene therapy to regulate the over‐expression of growth factor. In addition to genetic approaches to regulate wound healing, epigenetic approaches also exist. Antisense oligodeoxynucleotides have been shown to regulate wound repair in certain model systems and to determine the protein(s) necessary for normal wound healing. A novel approach to regulate the activity of collagen genes, thereby affecting fibrosis, is to use a sense oligodeoxynucleotide having the same sequence of the cis element which regulates the promoter activity of a particular collagen gene. This exogenous oligodeoxynucleotide will compete with the cis element in the collagen gene for the trans‐acting factor which regulates promoter activity. These epigenetic approaches afford the opportunity to regulate over‐expression of growth factor and therefore preclude the potential toxic effects of gene therapy. Both genetic and epigenetic approaches for regulating the wound healing process, either normal or aberrant wound healing, have certain advantages and disadvantages which are discussed in the present article.
Expression of cyclin‐dependent kinase inhibitors, p21cip1 and p27kip1, during wound healing in rats
Authors: Zhu Xudong , Hu Chengxiang , Zhang Yan , Li Lei , Wang Zhengguo
Published: March 2003

Wound healing is a physiological process in which growth of cells is stringently regulated. Cell growth is controlled by cell cycle‐related proteins in which the cyclin kinase inhibitors cause cell cycle arrest and inhibit proliferation. However, little is known about the expression and the role of cyclin kinase inhibitors during wound healing in vivo. This study was mainly designed to examine the expression of p21cip1 and p27kip1 in excisional wounds of full‐thickness skin in rats. Concomitant expression of proliferation marker Ki67 was also examined. Proliferation predominantly occurred in the first week after injury, peaking at postwounding day 5. Expression of both p21cip1 and p27kip1 at the gene and protein levels did occur during wound healing and showed an inverse gradient to that of Ki67. Constitutive p27kip1 was expressed throughout wound healing with low levels during the proliferating period of days 3 and 5 and increased levels during post‐mitotic and remodeling stages. In contrast, p21cip1 was expressed transiently with detectable levels only between days 7 and 14 by Western blot analysis. Immunohistochemically, epithelial cells, endothelial cells and fibroblasts all could express both p21cip1 and p27kip1. In conclusion, the overall results suggested that p21cip1 and p27kip1 may play a key role in supervising the growth resulting from cell proliferation in tissue repair.
Microenvironment and stem properties of bone marrow‐derived mesenchymal cells
Authors: BIANCHI GIORDANO , MURAGLIA ANITA , DAGA ANTONIO , CORTE GIORGIO , CANCEDDA RANIERI , QUARTO RODOLFO
Published: March 2003

Adult stem cells are self‐renewing, pluripotent, and able to repopulate the tissue in which they reside. Cells endowed with these properties have been isolated from several tissues and an increasing number of reports provide evidence of their ability, following transplantation, to engraft host tissues other than those of their origin. In this setting, interest in the well‐documented capacity of bone marrow stromal cells to undergo multilineage differentiation is growing. Neural and cardiomyogenic lineages have recently been proposed as additional differentiative pathways of these cells. However, culture conditions and inductive molecules can alter the behavior of bone marrow stromal cells and the microenvironment is critical for proper in vivo delivery. The maintenance of their stem properties and the possibility of reprogramming their commitment is a field of primary interest given the potential use of these cells in regenerative medicine. We discuss here how the microenvironmental cues, and the growth factors that physiologically govern commitment and subsequent differentiation, influence the properties of bone marrow stromal cells and modulate their engraftment into host tissues.