Structural changes in commercial agriculture

The basic idea of the conference on Structural Changes in Commercial Agriculture was planted in the spring of 1964 by Earl 0. Heady. He outlined for the North Central Farm Management Research Committee his concern about the kind and amount of response to both current and prospective structural changes in the commercial farm firm. Many changes represent adjustments to technological and other innovations originating in marketing, research, and educational agencies serving farmers.https://lib.dr.iastate.edu/card_reports/1025/thumbnail.jp

Revisiting Brain Atrophy and Its Relationship to Disability in Multiple Sclerosis

Brain atrophy is a well-accepted imaging biomarker of multiple sclerosis (MS) that partially correlates with both physical disability and cognitive impairment.Based on MRI scans of 60 MS cases and 37 healthy volunteers, we measured the volumes of white matter (WM) lesions, cortical gray matter (GM), cerebral WM, caudate nucleus, putamen, thalamus, ventricles, and brainstem using a validated and completely automated segmentation method. We correlated these volumes with the Expanded Disability Status Scale (EDSS), MS Severity Scale (MSSS), MS Functional Composite (MSFC), and quantitative measures of ankle strength and toe sensation. Normalized volumes of both cortical and subcortical GM structures were abnormally low in the MS group, whereas no abnormality was found in the volume of the cerebral WM. High physical disability was associated with low cerebral WM, thalamus, and brainstem volumes (partial correlation coefficients ~0.3-0.4) but not with low cortical GM volume. Thalamus volumes were inversely correlated with lesion load (r = -0.36, p<0.005).The GM is atrophic in MS. Although lower WM volume is associated with greater disability, as might be expected, WM volume was on average in the normal range. This paradoxical result might be explained by the presence of coexisting pathological processes, such as tissue damage and repair, that cause both atrophy and hypertrophy and that underlie the observed disability

Optic nerve head component responses of the multifocal electroretinogram in MS

ObjectiveTo employ a novel stimulation paradigm in order to elicit multifocal electroretinography (mfERG)-induced optic nerve head component (ONHC) responses, believed to be contingent upon the transformation in electrical transmission properties of retinal ganglion cell axons from membrane to saltatory conduction mechanisms, as they traverse the lamina cribrosa and obtain oligodendrocyte myelin. We further sought to characterize abnormalities in ONHC responses in eyes from patients with multiple sclerosis (MS).MethodsIn 10 normal subjects and 7 patients with MS (including eyes with and without a history of acute optic neuritis), we utilized a novel mfERG stimulation paradigm that included interleaved global flashes in order to elicit the ONHC responses from 103 retinal patches of pattern-reversal stimulation.ResultsThe number of abnormal or absent ONHC responses was significantly increased in MS patient eyes compared to normal subject eyes (p &lt; 0.001, by general estimating equation modeling, and accounting for age and within-subject, intereye correlations).ConclusionStudying the relationship between ONHC abnormalities and alterations in validated structural and functional measures of the visual system may facilitate the ability to dissect and characterize the pathobiological mechanisms that contribute to tissue damage in MS, and may have utility to detect and monitor neuroprotective or restorative effects of novel therapies

Microcystic macular oedema, thickness of the inner nuclear layer of the retina, and disease characteristics in multiple sclerosis: a retrospective study.

BackgroundMicrocystic macular oedema (MMO) of the retinal inner nuclear layer (INL) has been identified in patients with multiple sclerosis (MS) by use of optical coherence tomography (OCT). We aimed to determine whether MMO of the INL, and increased thickness of the INL are associated with disease activity or disability progression.MethodsThis retrospective study was done at the Johns Hopkins Hospital (Baltimore, MD, USA), between September, 2008, and March, 2012. Patients with MS and healthy controls underwent serial OCT scans and clinical assessments including visual function. OCT scanning, including automated intraretinal layer segmentation, yielded thicknesses of the retinal nerve fibre layer, the ganglion cell layer plus inner plexiform layer, the INL plus outer plexiform layer (the combined thickness of these layers was used as a surrogate measure of INL thickness), and the outer nuclear layer. Patients with MS also underwent annual brain MRI scans. Disability scores were compared with the Wilcoxon rank-sum test. Mixed-effects linear regression was used to compare OCT measures and letter-acuity scores. Logistic regression was used to examine the relations of baseline OCT thicknesses with clinical and radiological parameters.Findings164 patients with MS and 60 healthy controls were assessed. Mean follow-up was 25·8 months (SD 9·1) for patients with MS and 22·4 months (11·4) for healthy controls. Ten (6%) patients with MS had MMO during at least one study visit; MMO was visible at baseline in four of these patients. Healthy controls did not have MMO. Patients with MS and MMO had higher baseline MS severity scores (median 5·93 [range 2·44-8·91]) than those who did not have MMO at any time during the study (151 patients; 3·81 [0·13-9·47]; p=0·032), although expanded disability status scale (EDSS) scores were not significantly different (5·2 [1·0-6·5] for patients with MS and MMO vs 2·5 [0·0-8·0] for those without MMO; p=0·097). The eyes of patients with MS and MMO (12 eyes) versus those without MMO (302 eyes) had lower letter-acuity scores (100% contrast, p=0·017; 2·5% contrast, p=0·031; 1·25% contrast, p=0·014), and increased INL thicknesses (p=0·003) at baseline. Increased baseline INL thickness in patients with MS was associated with the development of contrast-enhancing lesions (p=0·007), new T2 lesions (p=0·015), EDSS progression (p=0·034), and relapses in patients with relapsing-remitting MS (p=0·008) during the study. MMO was not associated with disease activity during follow-up.InterpretationIncreased INL thickness on OCT is associated with disease activity in MS. If this finding is confirmed, INL thickness could be a useful predictor of disease progression in patients with MS.FundingNational Multiple Sclerosis Society, National Eye Institute, Braxton Debbie Angela Dillon and Skip Donor Advisor Fund

Partial correlations of normalized brain structure with one another in MS cases.

<p>Results are adjusted for linear effects of age and sex. The <i>p</i>-values are shown in parentheses, and results with <i>p</i><0.01 are shown in boldface.</p

Normalized brain structure volumes.

<p>Results with <i>p</i><0.01 are shown in bold face. <i>Abbreviations</i>. <i>HV</i>, healthy volunteers. <i>MS</i>, multiple sclerosis. <i>SD</i>, standard deviation.</p

Partial correlations of impairment measures with normalized structure volumes.

<p>Results are adjusted for linear effects of age and sex. The <i>p</i>-values are shown in parentheses, and results with <i>p</i><0.01 are shown in boldface. <i>Abbreviations</i>. <i>EDSS</i>, Expanded Disability Status Scale. <i>MSSS</i>, MS Severity Score. <i>MSFC</i>, Multiple Sclerosis Functional Composite <i>z</i>-score. <i>PASAT-3</i>, Paced Auditory Serial Addition Test, 3-second version.</p