Blur adaptation: clinical and refractive considerations

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.     

Abnormal spinal interactions from hand afferents to forearm muscles in writer's cramp.

OBJECTIVE: Spinal reflexes from hand to wrist muscles were investigated in writer's cramp. METHODS: Stimulus-triggered rectified EMG averages after ulnar nerve and cutaneous stimulation, in wrist flexors and extensors during tonic contraction, were compared in 18 controls and 19 patients. RESULTS: On the patient dystonic side, ulnar-induced EMG suppression was decreased in wrist extensors, and facilitation in wrist flexors modified dependent on the dystonic wrist posture during writing. No change was found on the patient non-dystonic side. Cutaneous stimulation increased wrist flexor EMG on both sides of the patients with normal wrist posture during writing, but had no effect in controls and patients with abnormal wrist posture. CONCLUSIONS: Comparison between cutaneous and mixed nerve stimuli suggests that spindle afferents from intrinsic hand muscles may mediate patients' ulnar-induced EMG modulations. Abnormal proprioceptive control was only observed on dystonic side, while bilateral unusual cutaneous control was found in patients. Changes in spinal transmission were partly related to the dystonic wrist posture, suggesting that systems involved in sensory processing can be differentially altered in writer's cramp. SIGNIFICANCE: Changes in spinal transmission, probably related to peripheral and/or cortical inputs, might either take part in primary or adaptive mechanisms underlying writer's cramp.     

Systematic review of methods to diagnose infection in foot ulcers in diabetes.

AIM: To undertake a systematic review of the diagnostic performance of clinical examination, sample acquisition and sample analysis in infected foot ulcers in diabetes. METHODS: Nineteen electronic databases plus other sources were searched. To be included, studies had to fulfil the following criteria: (i) compare a method of clinical assessment, sample collection or sample analysis with a reference standard; (ii) recruit diabetic individuals with foot ulcers; (ii) present 2 x 2 diagnostic data. Studies were critically appraised using a 12-item checklist. RESULTS: Three eligible studies were identified, one each on clinical examination, sample collection and sample analysis. For all three, study groups were heterogeneous with respect to wound type and a small proportion of participants had foot ulcers due to diabetes. No studies identified an optimum reference standard. Other methodological problems included non-blind interpretation of tests and the time lag between index and reference tests. Individual signs or symptoms of infection did not prove to be useful tests when assessed against punch biopsy as the reference standard. The wound swab did not perform well when assessed against tissue biopsy. Semiquantitative analysis of wound swab might be a useful alternative to quantitative analysis. The limitations of these findings and their impact on recommendations from relevant clinical guidelines are discussed. CONCLUSION: Given the importance of this topic, it is surprising that only three eligible studies were identified. It was not possible to describe the optimal methods of diagnosing infection in diabetic patients with foot ulceration from the evidence identified in this systematic review.     

Contribution of hypoxia-measuring molecular imaging techniques to radiotherapy planning and treatment

Hypoxia is related to poor prognosis because it is associated to chemo-and radioresistance. During recent years the evolution of imaging methods like PET/CT and MRI has meant the appearance of new perspectives with direct implications in radiation therapy. We discuss previous experiences in staging, planning and in the follow-up process with these techniques for measuring tumour hypoxia.     

Assay of cytomegalovirus susceptibility to ganciclovir in renal and heart transplant recipients

Ganciclovir (GCV) prophylaxis or pre-emptive therapy significantly reduce the rate of cytomegalovirus (CMV) disease and viremia, but increase the potential for emergence of ganciclovir-resistant CMV strains. The inhibitor concentration at 50% (IC(50)) of GCV from 156 CMV isolates from 59 renal or heart transplant recipients was calculated by means of a rapid phenotypic susceptibility assay. Twenty-seven strains were from 14 patients undergoing GCV therapy. The IC(50) was higher in patients under the prophylaxis regimen. One CMV strain, from a heart transplant recipient, became GCV-resistant after 1 month of therapy (IC(50)=13.7 micromol/l). These data, together with clinical and virological markers, suggested that a switch to foscarnet was necessary, and good evolution was observed. Thus, assay of CMV susceptibility to GCV could be helpful in clinical management.     

Characteristics of pollinosis caused by Betula in patients from Ourense (Galicia, Spain).

A retrospective study was performed to describe the features of the pollinosis caused by Betula in the area of Ourense, Spain. The pollen count was carried out with a Lanzoni volumetric Hirts spore trap (1993-2000). The Betula pollen represented 5% over the annual total (annual mean quantity: 965 grains). It was present in the air from March to mid-May. The highest peaks took place in April (maximum values mean: 131 grains/m3). The medical records of 222 patients (mean age 25.66 years) diagnosed with pollinosis (1998-2000), who lived at less than 30 km. from the spore trap, were reviewed. In all of them, the skin-prick test (SPT) was carried out with pollen allergens. The percentages of positive SPT were: Lolium perenne, 91.89% (16.6% monosensitized); Plantago lanceolata, 71.17% (1.26% monosensitized); Betula alba, 41.89% (10.75% monosensitized); Platanus hybrida, 34.95%; Olea europea, 10.36%; and Parietaria judaica, 6.3%. The mean age of Betula monosensitized patients was 44.7 years. The majority of them had symptoms in March-April, 40% had asthma symptoms, 80% had lived in Central Europe, and 30% of them presented an oral allergy syndrome to fruits. There were 41.93% of the patients with positive SPT to Betula pollen who had asthma symptoms, in comparison with 23.25% of the patients with negative SPT to Betula (p = 0.0034). There were 20.28% of the patients with positive SPT to Betula pollen, who had lived in Central Europe, in comparison with 4.27% of the patients with negative SPT to Betula, p: 0.00049. The relative risk of sensitization was 2.05. CONCLUSIONS: Betula pollen was the second cause of clinical pollinosis in our patients, after grass, being responsible of the symptoms in the early spring, in a small number of the patients in their forties. The presence of asthma was higher in Betula sensitized patients, and the residence in Central Europe was a sensitization risk factor.