You'd better walk alone: Changes in forest composition affect pollination efficiency and pre-dispersal cone damage in Iberian Juniperus thurifera forests

Changes in land-use patterns are a major driver of global environmental change. Cessation of traditional land-use practices has led to forest expansion and shifts in forest composition. Consequently, former monospecific forests maintained by traditional management are progressing towards mixed forests. However, knowledge is scarce on how the presence of other tree species will affect reproduction of formerly dominant species. We explored this question in the wind-pollinated tree Juniperus thurifera. We hypothesised that the presence of heterospecific trees would have a negative effect on cone production and on the proportion of cones attacked by specialised predators. We assessed the relative importance of forest composition on cone production, seed development and pre-dispersal cone damage on nine paired pure and mixed J. thurifera forests in three regions across the Iberian Peninsula. The effects of forest composition on crop size, cone and seed characteristics, as well as damage by pre-dispersal arthropods were tested using mixed models. Cone production was lower and seed abortion higher in mixed forests, suggesting higher pollination failure. In contrast, cone damage by arthropods was higher in pure forests, supporting the hypothesis that presence of non-host plants reduces damage rates. However, the response of each arthropod to forest composition was species-specific and the relative rates of cone damage varied depending on individual tree crops. Larger crop sizes in pure forests compensated for the higher cone damage rates, leading to a higher net production of sound seeds compared to mixed forests. This study indicates that ongoing changes in forest composition after land abandonment may impact tree reproduction.

Efficiency of pollination and satiation of predators determine reproductive output in Iberian Juniperus thurifera woodlands

Fruit production in animal-dispersed plants has a strong influence on fitness because large crops increase the number of seeds dispersed by frugivores. Large crops are costly, and environmental control of plant resources is likely play a role in shaping temporal and spatial variations in seed production, particularly in fluctuating environments such as the Mediterranean. The number of fruits that start to develop and the proportion of viable seeds produced are also linked to the number of flowers formed and the efficiency of pollination in wind-pollinated plants. Finally, large fruit displays also attract seed predators, having a negative effect on seed output. We assessed the relative impact of environmental conditions on fruit production, and their combined effect on seed production, abortion and seed loss through three predispersal predators in Juniperus thurifera L., sampling 14 populations across the Iberian Peninsula. Wetter than average conditions during flowering and early fruit development led to larger crop sizes; this effect was amplified at tree level, with the most productive trees during more favourable years yielding fruits with more viable seeds and less empty and aborted seeds. In addition, large crops satiated the less mobile seed predator. The other two predispersal predators responded to plant traits, the presence of other seed predators and environmental conditions, but did not show a satiation response to the current-year crop. Our large-scale study on a dioecious, wind-pollinated Mediterranean juniper indicates that pollination efficiency and satiation of seed predators, mediated by environmental conditions, are important determinants of reproductive output in this juniper species.

Impact of fatigue in multiple sclerosis: the Fatigue Impact Scale for Daily Use (D-FIS)

Objective The Fatigue Impact Scale for Daily Use (D-FIS) is an eight-item instrument designed to measure subjective daily experience of fatigue. This study sought to determine the metric properties of the D-FIS in multiple sclerosis (MS) patients.

Methods Sixty-eight patients with operationally-defined MS and fatigue (54.8% of the sample) underwent the D-FIS. Usual clinical measures for MS, the Montgomery-Asberg Depression Rating Scale (MADRS) and the Functional Assessment of Multiple Sclerosis (FAMS) were also applied. In addition, patients with fatigue completed the Fatigue Descriptive Scale, the Multidimensional Fatigue Inventory (MFI), a Visual Analogue Scale for Fatigue (VAS-F), and a Global Perception of Fatigue Scale (GPF).

Results Full computable data, 95.6%; both floor and ceiling effect=1.54%; item-total correlation =0.62 (item 1) to 0.84 (item 6); Cronbach's alpha =0.91; item homogeneity =0.55; standard error of measurement =3.18; convergent validity with other fatigue measures = -0.57 (VAS-F); 0.52 (GPF); and 0.46 (MFI-general fatigue). Test-retest reliability (ICC) =0.81. There was a strong association between health-related quality of life (HRQoL) (FAMS) and D-FIS (rS=0.70).

Conclusions In this study, D-FIS proved to be a feasible and valid instrument for measuring MSrelated fatigue, a frequent symptom associated with deterioration of patients' HRQoL. Multiple Sclerosis 2007; 13: 645-651. http://msj.sagepub.com

[Findings using magnetic resonance in a patient with non-traumatic anosmia]

INTRODUCTION

The presence of alterations in the neuroimaging in patients with anosmia without traumatic antecedents is not frequent.

CASE REPORT

Male aged 38 who came to surgery after having suffered, 6 months earlier, for 1 week, a picture of intense, oppressive holocranial headache, accompanied by fever. Associated with this, an acute complete anosmia also began and persisted up to the moment the patient came for consultation. It was not associated with any infection of the respiratory tract, there was no history of cranial trauma, no ingestion of medicines nor toxins, nor had he been exposed to toxic products. The exploration to which he was submitted only showed an anosmia and was otherwise found to be normal. Cranial MRI showed signal alterations in both lower (orbitary) convolutions of the frontal lobes, in the anterior region of the right temporal lobe and in both olfactory nerves. Tests for HIV serology, parotiditis, hepatitis B and C virus, HSV, VZV, Mycoplasma pneumoniae and lues were negative. The acute onset of the anosmia in midst of a picture of febricula and headaches made us suspect the presence of an infectious aetiology, and the alterations found in the neuroimaging could be due to post encephalic lesions, with a special predilection for olfactory areas.

CONCLUSIONS

1. MRI plays a fundamental role in the topographic and aetiological evaluation of olfactory dysfunctions of a central origin; 2. Affectation of the central olfactory passages of an infectious aetiology in a non HIV patient and with neuroimaging findings is a rare complication.

Prestroke dementia

OBJECTIVE

To determine the frequency, associated factors and outcome of dementia previous to a stroke.

DESIGN

Cross-sectional study of a cohort of 324 consecutive unselected stroke patients (mean age 70.9 years, range 20-98; 255 ischaemic, 46 haemorrhagic and 25 indefinite).

METHODS

Cognitive and functional status prior to stroke were assessed by means of an interview to a relative, a short version of the Informant Questionnaire on Cognitive Decline in the Elderly and the Barthel Index. The DSM-III-R criteria were used to establish the diagnosis of prestroke dementia. Clinical and CT features of patients with and without prestroke dementia were compared.

RESULTS

Forty-nine patients (15%) were demented before stroke; they were significantly older, less well educated, they had more frequently female gender, prior cerebrovascular disease, cerebral and medial temporal lobe atrophy and leukoaraiosis in the CT scan, and they had a higher mortality rate. Female sex (OR 3.7, CI 95% 1.2-12), low education (OR 2.1, CI 95% 1.1-4.2), previous stroke (OR 3.6, CI 95% 1.2-11), and cerebral atrophy (OR 3.8, CI 95% 1.7-8.3) were independently associated with prestroke dementia in the logistic regression analysis.

CONCLUSIONS

Fifteen percent of stroke patients have prestroke dementia and they have a worse outcome. Factors associated with prestroke dementia are reminiscent both of degenerative and vascular brain pathology.

Poststroke dementia : clinical features and risk factors

BACKGROUND AND PURPOSE

The goal of the present study was to examine a series of putative risk factors of poststroke dementia (PSD), especially those factors usually associated with cerebrovascular disease and degenerative dementia, in a series of 251 consecutive unselected stroke patients.

METHODS

A standard protocol was prospectively applied at admission and 3 months after stroke; this protocol included clinical, functional, and cognitive assessments, hemogram and serum biochemistry, ECG and CT exams, apolipoprotein E and angiotensin-converting enzyme genotype, and neuropsychological examination. After a neuropsychological examination and an interview with a relative, the following diagnostic criteria were used: the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV for dementia after stroke, DSM-III-R for previous dementia and dementia stage, and Association Internationale pour la Recherche et l'Enseignement en Neurologie (NINDS-AIREN) for vascular dementia.

RESULTS

Seventy-five cases (30%) demonstrated dementia at 3-month follow up; 25 of them (10%) had demonstrated dementia before the stroke. Dementia was unrelated to type (ischemic/hemorrhagic) or location of stroke, vascular factors (hypertension, diabetes, ischemic heart disease, or hypercholesterolemia), apolipoprotein E or angiotensin-converting enzyme genotype, and serum homocysteine. Age (odds ratio [OR] 1.1, 95% CI 1.03 to 1.2), previous nephropathy (OR 6.1, 95% CI 1.5 to 24.3), atrial fibrillation (OR 4.4, 95% CI 1. 4 to 13.9), low Canadian Neurological Scale score at discharge (OR 0. 5, 95% CI 0.4 to 0.6), and previous mental decline assessed by the shortened Spanish version of the Informant Questionnaire on Cognitive Decline in the Elderly (SS-IQCODE; OR 1.2, 95% CI 1.1 to 1. 4) were the correlates of dementia in logistic regression analyses. The same risks factors were found when cases with previous dementia and with hemorrhagic stroke were excluded.

CONCLUSIONS

Dementia is frequent after ischemic or hemorrhagic stroke. Age, nephropathy, atrial fibrillation, previous mental decline, and stroke severity independently contribute to the risk.