Search

A 13-year-old Quarter Horse mare presented for evaluation of chronic intermittent colic. Following extensive diagnostics, abdominal radiographs revealed two round, radiopaque objects in the caudal abdomen. Palpation per rectum and transrectal ultrasonography of the reproductive tract confirmed that the round objects were uterine marbles. Dinoprost tromethamine (Lutalyse, 5 mg i.m. q. 24 h for 2 days) was administered to bring the mare into oestrus, and both uterine marbles were manually removed from the uterus following digital dilation of the relaxed cervix. Follow-up with the owner 12 months after discharge revealed that the mare had shown no further signs of abdominal discomfort since having the uterine marbles removed. To the authors' knowledge, this is the first published report of chronic intermittent colic attributed to uterine marbles in a mare. [ABSTRACT FROM AUTHOR]

Placentitis is reported to be the cause of 9.8-33.5% of abortions, stillbirths and perinatal losses in horses. Bacterial infections are responsible for 53% of placentitis cases with Streptococcus equi ssp. zooepidemicus being isolated in 28% of these cases. Clinically, mares may have a vaginal discharge, show udder development, lactate prenatally and deliver a premature or dead foal. Major aspects of the pathogenesis of infectious preterm delivery that may require more effective therapeutic targeting are myometrial contraction, immunological aspects of preterm delivery, and the effects of proinflammatory cytokine signalling on activation of the fetal hypothalamic-pituitary-adrenal axis. This article focuses on current knowledge of inflammatory signalling secondary to equine placentitis, and the interplay among inflammation, loss of myometrial quiescence and activation of the fetal hypothalamic-pituitary-adrenal axis. [ABSTRACT FROM AUTHOR]

Citation information: Strang NC, Day M, Gray LS & Seidel D. Accommodation steps, target spatial frequency and refractive error. Ophthalmic Physiol Opt 2011, 31, 444-455. doi: 10.1111/j.1475-1313.2011.00855.x Abstract Purpose: Errors in the accommodation response of myopes have been reported in many studies although questions remain about the exact differences in accommodation steps when compared with emmetropic individuals. Methods: The characteristics of the accommodation step response to large (4/1D) and small (3/2D) steps in targets with low (0.5 cpd), mid (4 cpd) and high (16 cpd) spatial frequency (SF) information was measured in myopes (MYOs) and emmetropes (EMMs). Results: In terms of step size, the larger steps showed a greater response in the 4 cpd condition than the 0.5 and 16 cpd conditions and an improved percentage correct response in the 4 cpd compared to the 16 cpd steps. In small step conditions target SF had less effect upon the magnitude of the response. In terms of refractive group differences, MYOs had a lower proportion of correct accommodation responses compared to EMMs during the small steps only, however, when correct steps were performed there were no differences in the characteristics of both large and small step responses between MYOs and EMMs. Conclusions: These findings suggest that MYOs have some difficulty interpreting small changes in defocus to initiate or possibly fine tune a small accommodation response, however, when a correct accommodation step response is made, the MYOs accommodation plant responds in a similar manner to EMMs. [ABSTRACT FROM AUTHOR]

Aim: Dynamic measurement of accommodation in subjects with myopia usually involves recording through soft contact lenses (CLs) to correct the refractive error. Conversely, dynamic accommodation measurement in emmetropic control subjects is generally undertaken without any corrective lenses. The aim of this experiment was to determine whether CL correction affects the measurement of accommodation microfluctuations using infrared refractometry, and whether this needs to be considered in studies which attempt to compare accommodation responses between the two groups. Methods: Ten young emmetropic subjects viewed a high contrast Maltese cross target monocularly using the right eye at a target vergence of 0 D. The subjects viewed the target under two conditions: with CL condition and without CL condition, where the subjects viewed the target with the eye only. Accommodation responses of the right eye were recorded continuously for 2 min at a sampling rate of 52 Hz using the Shin-Nippon SRW-5000 autorefractor. Results: No significant difference (two-tailed paired t-test, t9 = −1.499, p = 0.168) was found in mean accommodation response between the with CL (mean ± S.D. = −0.02 ± 0.24 D) and without CL conditions (mean ± S.D. = +0.01 ± 0.25 D). No significant (two-tailed paired t-test, t9 = 0.151, p = 0.883) difference in the magnitude of the accommodation microfluctuations was found between the with CL (mean ± S.D. = 0.162 ± 0.04 D) and without CL condition (mean ± S.D. = 0.169 ± 0.04 D). Power spectrum analysis revealed no differences in the characteristics of the microfluctuations waveform between the two conditions. A control experiment carried out on a subgroup of five subjects using a negative (−3 D) CL demonstrated that there was no significant effect of the dioptric power of the CL on the magnitude of the accommodation microfluctuations (anova: F3,15 = 0.254, p = 0.782). Conclusion: Thin soft CLs do not affect the magnitude or frequency characteristics of accommodation microfluctuations when measured using the Shin-Nippon SRW-5000. [ABSTRACT FROM AUTHOR]

Purpose: Microfluctuations of accommodation are known to increase in magnitude with increasing accommodation stimulus. Reduced sensitivity to blur in myopic subjects could also lead to increases in the magnitude of the microfluctuations. The aim of this study is to examine the effect of variations in accommodation stimulus upon the microfluctuations in different refractive groups. Methods: Thirty-six subjects were divided into three groups depending upon their refractive error and age of onset of their myopia; 12 emmetropes (EMMs), 12 early onset myopes (EOMs) and 12 late-onset myopes (LOMs). Steady-state accommodation responses were recorded continuously for 2 min using the Shin-Nippon SRW-5000 autorefractor at a sampling rate of 52 Hz while viewing targets at accommodation stimuli levels of 0, 1, 2, 3 and 4 D in a Badal (+5 D) optical system. Results: The EMMs and EOMs showed systematic increases in the root mean square (r.m.s.) value of the microfluctuations with increasing accommodation stimulus. In contrast, no systematic variation with accommodation stimulus was found for the LOMs. Power spectrum analysis demonstrated that increases in the size of the microfluctuations were mediated by increases in the power of the low frequency components of the accommodation response. Conclusions: The magnitude of the microfluctuations in the EMMs and EOMs may be influenced primarily by accommodation response-induced zonular relaxation effects or to changes in the physical properties of the accommodation plant with increasing accommodation response. The LOMs may have an increased baseline neural blur threshold, which appears to modulate the magnitude of the accommodative microfluctuations for low accommodation levels. At higher accommodation demands, the changes in the physical properties of the accommodation plant or the zonular relaxation effects appear to exceed the blur threshold, and the known association between microfluctuations and accommodation stimulus level is restored. [ABSTRACT FROM AUTHOR]

Whilst the methodology of adult letter acuity measurement has been substantially refined over the last two decades, relatively little development has occurred in methods for quantifying letter acuity in young children. This study compares a recently developed visual acuity test (Glasgow Acuity Cards), which incorporates several key design features used in adult test charts to improve the sensitivity and reliability of visual acuity measurements. The equivalence of acuity measurements made with Glasgow Acuity Cards were compared with the Bailey-Lovie logMAR chart and Snellen chart in adults, and with traditional Single Letter Acuity and a modified Single Letter Acuity test in children. The test-retest reliability of acuity measurements made with Glasgow Acuity Cards and the Single Letter Acuity tests were also assessed in a large group of visually normal children. In addition, the ability of the pre-school letter acuity tests to detect differences in acuity between the two eyes, and to detect amblyopia were examined. Ninety-five percent of vision measurements made with the Bailey-Lovie chart and Glasgow Acuity Cards differ by less than 0.07 log unit. Furthermore, the sensitivity of Glasgow Acuity Cards to detecting changes in acuity longitudinally and inter-ocular differences in acuity is considerably greater as compared with traditional Single Letter Acuity tests. Improvements in paediatric acuity chart design are important for the effective detection and management of children with amblyopia. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion This work aimed to establish the largest UK and Ireland consensus on myopia management in children and young people (CYP).A modified Delphi consensus was conducted with a panel of 34 optometrists and ophthalmologists with expertise in myopia management.Two rounds of voting took place and 131 statements were agreed, including that interventions should be discussed with parents/carers of all CYP who develop myopia before the age of 13 years, a recommendation for interventions to be publicly funded for those at risk of fast progression and high myopia, that intervention selection should take into account the CYP's hobbies and lifestyle and that additional training for eye care professionals should be available from non‐commercial sources. Topics for which published evidence is limited or lacking were areas of weaker or no consensus. Modern myopia management contact and spectacles are suitable first‐line treatments. The role and provision of low‐concentration atropine needs to be reviewed once marketing authorisations and funding decisions are in place. There is some evidence that a combination of low‐concentration atropine with an optical intervention can have an additive effect; further research is needed. Once an intervention is started, best practice is to monitor non‐cycloplegic axial length 6 monthly.Research is needed to identify those at risk of progression, the long‐term effectiveness of individual and combined interventions, and when to discontinue treatment when myopia has stabilised. As further evidence continues to emerge, this consensus work will be repeated to ensure it remains relevant. [ABSTRACT FROM AUTHOR]

We investigate the influence of stimulus contrast upon contour interaction in normal and amblyopic subjects. Using a computer generated acuity task, flanked and unflanked acuities were measured psychometrically at both high contrast (80%) and low contrast (6%), in a group of 19 normal and 11 amblyopic subjects. The crowding ratio for high contrast letters was found to be significantly higher than that for low contrast letters. The extent of the crowding zone was measured at high and low contrast by varying the separation of the optotype and flanking bars. The crowding zone measurement was repeated for the high contrast optotypes using dioptric blur. The position of the flanking contours was found to have a significant effect on letter resolution at high contrast but no significant effect was demonstrable at low contrast. With the addition of dioptric blur the effect of contour interaction became negligible at high contrast. These findings support the hypothesis that the crowding effect is: (1) similar in normal and amblyopic eyes when tested at threshold; (2) is contrast dependent appearing only for high contrast optotypes. [ABSTRACT FROM AUTHOR]

It is feasible that small temporal variations in steady-state accommodation may provide feedback to the accommodation control system through changes in retinal image contrast and that this feedback may be used to maintain an optimal accommodation response. The complex waveform of microfluctuations is dominated by two distinct regions of activity; a low frequency component (LFC <0.6 Hz) and a high frequency component (1.0 ≤HFC ≤ 2.3 Hz). Whereas the HFCs appear to be correlated with some intraocular manifestation of arterial pulse the contribution of the LFCs to the control of steady-state accommodation is unclear. The present study investigates the effect of target luminance on the waveform of accommodative microfluctuations. Three young emmetropic observers viewed monocularly a high contrast (90%) Maltese cross target placed at a vergence equal to their dark-focus level of accommodation in a Badal stimulus system. The luminance of the target was varied from 0.002 to 11.63 cd m[SUP-2] in nine equal logarithmic steps. Five continuous accommodation signals were collected for each viewing condition at a sampling rate of 102.4 Hz, and average power spectra subsequently calculated with a frequency resolution of 0.1 Hz. One-way ANOVA revealed a significant variation in the root-mean-square (r.m.s.) value of the microfluctuations (F = 19.795, d.f. 124, P =0.0001) which could be attributed mainly to increases in the r.m.s. value for the two lowest luminances (0.002 and 0.004cd m[SUP-2]). Power spectrum analysis revealed that these changes in the microfluctuations could be attributed to increases of power in the LFC. No systematic variation of the HFC could be observed with changing luminance level. The increase in power of the LFC as retinal-image quality is degraded suggests that it is this component which is used in the control of blur-driven accommodation responses. [ABSTRACT FROM AUTHOR]

The purpose of this review is to give an account of the issues raised by reports that myopia can be treated by operant conditioning or biological feedback. Devices are available that provide auditory feedback of accommodative state such that variation in tone frequency provides a means by which the patient can monitor his or her ability to induce changes in accommodation response, the task thus being to change the pitch of the tone in a direction corresponding to a more distant far point. The aim of a training programme is to reinforce and establish control over the accommodative response by a process akin to operant conditioning and subsequently to transfer the skill to normal visual environments such that a manifest reduction in myopia becomes apparent. Although there are reports that the technique can induce a reduction in myopia by up to 3 D the findings are of limited value owing to the lack of objective data, for example pre- and post-training cycloplegic refraction. The pre- and post-training measures of subjective letter acuity used by many studies are, with repeated trials, particularly vulnerable to individual differences in the ability to learn how to discriminate and interpret blurred images. The review concludes that more comprehensive clinical trials are needed before accommodation biofeedback can qualify as an established method of clinical treatment of myopia. The trials should be designed to encompass the following issues: the characteristics of a feasible physiological model linking accommodation and myopia development; the rationale with regard to patient selection; the technical performance of the optometer employed; the characteristics of the control group used; the criteria for assessment of myopic change; the transfer of training to performance in normal visual environments; the economic viability of the programme of training and equipment; and the skill, training and knowledge of the clinician implementing the training programme. [ABSTRACT FROM AUTHOR]

The article focuses on a study conducted to identify the commonality and heterogeneity of interpersonal styles of heroin abusers measured by the Fundamental Interpersonal Relations Orientation-Behavior (FIRO-B), to compare the frequency of types found in the sample to normative data, and to compare interpersonale style types on preselected measures of personality, psychopathology, demographics, and treatment outcome listed below that would provide empirical and construct validity of the Ryan schema. Results of the study provide objective data that indicate that difficulty with interpersonal relations as assessed by the FIRO-B is confirmed by self-report and interview in this sample of drug abusers.

To characterize IgE levels at birth and changes in those levels during the first year of life and to identify factors that might influence IgE levels in infancy, we measured IgE levels in 1074 umbilical cord sera and in 697 sera obtained at 9 months of age in a healthy population of infants enrolled at birth into the Children's Respiratory Study in Tueson, Arizona, U.S.A. Serum IgE levels at birth and 9 months were log normally distributed with geometric means of 009 and 3-87 IU/ml, respectively. Cord serum IgE levels were unaffected by maternal smoking. Levels varied according to month of birth with a nadir in September. Cord and 9-month serum IgE levels were higher in boys than in girls, Hispanics compared with Anglos, and infants who developed eczema compared with those who did not but the mean increases in log IgE from birth to 9 months were not significantly affected by these factors. A significant correlation between IgE levels at cord and 9 months was observed (r=0.44; P < 0.0001). Also, mean log IgE levels at 9 months in infants grouped according to cord serum IgE levels maintained the same rank order of mean values as the cord groups. These data indicate that 9-month IgE levels are influenced by cord serum IgE levels and that the main influence of gender, ethnicity and susceptibility to eczema on IgE levels occurs before birth. [ABSTRACT FROM AUTHOR]

Purpose: When measuring peripheral retinal shape using the IOLMaster, measurements have been taken with the instrument in a fixed position and the subjects rotating their eye to measure peripherally. However, eye rotation could affect the peripheral ocular shape measures. The aim of this experiment is to determine the effect of eye rotation upon the measurement of peripheral retinal shape in myopic and hyperopic subjects using the IOLMaster. Methods: 20 subjects participated with informed consent in the experiment [10 myopes (MYO) and 10 hyperopes (HYP)]. All subjects were visually normal with visual acuity of 0.0 logMAR or better. The mean age of the subjects was 21.4 ± 2.2 years, and all were students in the University. Cycloplegia and mydriasis were induced using 1.0% cyclopentolate and the measurements were taken 30 min after instillation of the eyedrops. Peripheral retinal dimensions were measured with the IOLMaster (Carl Zeiss Ltd., Welwyn Garden City, UK) which measures axial length using partial coherence interferometry. 5 measures of axial length were taken at 10 degree intervals from 0–40 degree nasally and temporally using two different experimental paradigms. Experiment 1: Subjects rotated their eye to view an LED target array, attached to the front of the instrument. Experiment 2: Subjects maintained fixation upon a stationary target in the primary position while the IOL-Master was rotated about the centre of rotation of the eye. The data was fitted with second order polynomials with separate curves being fitted to the temporal and nasal profiles to take into account any retinal asymmetry. Results: A significant difference ( p < 0.01) was found in the mean second order coefficients for the temporal and nasal retinal profiles in the MYO subjects, with the temporal retina having the lower coefficient. There was no significant difference between temporal and nasal second order coefficients in the HYP subjects. Eye rotation produced a significant shift in the second order coefficients for both temporal ( p < 0.01) and nasal ( p < 0.01) retinal profiles in the MYO group, with the coefficients becoming smaller with ocular rotation. No significant effect of eye rotation was found in the HYP group. Conclusions: Asymmetry between the temporal and nasal retinal profiles is more pronounced in the myopic eye. Ocular rotation has a substantial and measurable effect on the shape of the myopic eye, but no measurable effect is found in the hyperopic eye. These results are indicative of substantial structural differences between the eyes of subjects with myopia and hyperopia. When measuring peripheral retinal shape these factors should be taken into account. [ABSTRACT FROM AUTHOR]

Purpose: We have shown previously that proximal stimulation using size change can enhance or degrade accommodation step responses in open and closed loop conditions. The aim of the current experiment is to determine the relationship between the perceptual response to proximal stimulation based on size change and blur change for a range of target vergences. Methods: Perceptual thresholds for pure blur change, pure size change, coherent blur and size change and conflicting blur and size change were measured monocularly in 12 visually normal subjects (mean refractive error of -0.79D ± 2.41D and mean age 25.17 years ±3.10 years) using a 2-alternative forced-choice technique with 20 presentations per condition. Threshold estimates were obtained from psychometric functions using the bootstrap method. All subjects were fully corrected and had normal amplitudes of accommodation for their age. Threshold for proximal perception to blur only stimulation was established using target vergence changes of 0, 1, 2 and 3D. The effect of size change was then assessed at the same four levels of blur change. Stimuli were presented randomly with the position of the near and far vergences also randomised. This was repeated under four conditions: (1) Blur only. (2) Size only. (3) Size change coherent with the vergence change. (4) Size change conflicting with the vergence change. Targets consisted of pairs of photographic slides that contained strong monocular size and depth cues which were viewed successively in a 4D Badal lens system. On each trial the subjects compared the perceived proximity of the targets. Results: Considerable individual variation was found in the subject's perceptual responses to the four experimental conditions presented. The responses of all subjects were predicted by one of the following rules: (1) No effect of size. (2) Blur and size interact constructively. (3) No effect of blur. (4) Blur elicits a proximal response but size is used to determine the direction of the proximal effect. Without any size cue, eight subjects (66%) identified the direction of the vergence change correctly while the remaining subjects consistently perceived the target with lower dioptric vergence to be closer. The threshold required to accurately determine proximity from blur only cues was 2.27D ± 0.31D. In the absence of blur, size cues induced a proximal effect in 33% ( n = 4) subjects. The combination of size and blur cues produced a variety of response patterns, some subjects’ responses were dominated by blur cues while others relied heavily on size stimulation. Conclusions: Our ability to perceive a target as close can be dependent upon either size and/or accommodation signals. Interactions between the stimuli of dioptric target vergence and target size were found to be additive for producing a perceived proximity response. [ABSTRACT FROM AUTHOR]

Background/aims: To pilot a pharmacodynamic (PD) model of short-term androgen administration that may be used to predict long-term effects of androgen administration in postmenopausal women. The study was specifically designed to identify biomarkers that evaluate early skin response to exogenous androgens. The clinical consequences of androgen administration include hirsutism and acne. Skin biopsies were performed to document morphological changes in the pilosebaceous unit (PSU) and gene expression changes (Taqman and microarray). Functional skin response was gauged by measuring sebum excretion rates (SER).Methods: A double-blind, randomized, placebo-controlled, parallel-group study was conducted in 36 healthy postmenopausal female subjects to identify early biomarkers of androgen administration. Subjects were randomized to receive either 2.5 mg of transdermal testosterone gel (TTG; AndroGel®), 300 μg of TTGtransdermal testosterone gel, or placebo gel, daily for 6 weeks in a 1:1:1 ratio. Skin biopsies were performed to document morphological changes in the pilosebaceous unit (PSU) and gene expression changes (Taqman and microarray). Five-mm skin punch biopsies were obtained from the back of subjects at baseline, after 6 weeks of treatment, and 4 weeks post treatment. Biopsies were analyzed for histological changes characterized by total sebaceous gland volume and sebocyte cell size. Skin biopsies were also analyzed for molecular skin changes using skin Taqman/microarray assays. Measurements of sebum excretion rates (SER) were obtained at baseline and after 6 weeks of treatment.Results: Six weeks of treatment with the 2.5-mg TTGdose of AndroGel® increased sebaceous gland volume on average by 42% (p=0.0410) and sebum excretion rateSER by 52% (p=0.0021) relative to placebo. Microarray and Taqman analyses on skin samples also demonstrated changes in the 2.5-mg TTG AndroGel® group. Histological and molecular findings were noted to be reversible 4 weeks after discontinuing therapy.Analysis of Total Sebaceous Gland Volume (106 μm3) at Week 6 (See Tables 1 and 2)Analysis Results for SER at Week 6Conclusions: TTG treatment is associated with marked increases in sebaceous gland volume and SER, consistent with side effects including hirsutism and acne. Biomarkers sufficiently robust to support using to test for androgen-mediated skin effects in postmenopausal women were identified.Clinical Pharmacology & Therapeutics (2005) 79, P84–P84; doi: 10.1016/j.clpt.2005.12.299 [ABSTRACT FROM AUTHOR]

A large-scale immunoaffinity (IA) purification process was developed for the isolation of recombinant soluble antigen CD4 (sCD4) from Escherichia coli fermentations. The monoclonal antibody used for IA purification of sCD4 recognized a conformation-dependent epitope on the surface of domain 1 of CD4. IA chromatography was used to purify both sCD4-183, consisting of the N-terminal 183 amino acids of human CD4, and sCD4-PE40, a fusion protein consisting of the N-terminal 178 amino acids of CD4 and amino acids 1-3 and 253-613 of Pseudomonas exotoxin A (PE40). sCD4-183 was purified from E. coli cell pellets using cell disruption, protein solubilization, oxidation, Q-Sepharose anion-exchange and IA chromatography steps. sCD4-PE40 was purified from cell pellets using cell disruption, protein solubilization, oxidation, Cu(2+)-immobilized metal-affinity chromatography, anion-exchange and IA chromatography steps. The IA-purified sCD4 analogues demonstrated the correct apparent molecular masses on SDS/PAGE. The immobilized monoclonal antibody appeared to select for correctly folded CD4 protein, since sCD4-183 and sCD4-PE40 purified by the IA method bound human-immunodeficiency-virus glycoprotein gp120 (HIV gp120) in vitro. sCD4-PE40 purified by IA chromatography also inhibited protein synthesis in CV-1 cells expressing HIV gp120/160 at the cell surface. Relatively high recoveries of sCD4-183 and sCD4-PE40 were observed in the IA step of the purification process (71 and 79% recovery respectively). The results demonstrate that immobilized monoclonal antibodies directed against conformational epitopes may be used for rapid purification of gram amounts of correctly folded protein from mixtures of oxidized E. coli proteins.