Are allergen batch differences and the use of double skin prick test important?

BACKGROUND: Skin prick tests (SPT) are widely used both in clinical diagnostics and in research. The standardization of allergen extracts is well documented to be crucial for the validity of SPT, whereas less emphasis has been placed on reproducibility and the SPT procedure itself. The objectives of this study are to clarify how the double skin prick test procedure influence the sensitivity and specificity of the test and to analyse the differences in weal size in skin prick tests between two batches of allergen extracts from the same vendor. METHODS: The association between rhinitis and SPT was assessed among 1135 persons from a general population sample. SPT was performed twice with 10 common aeroallergens. In a subsample of 90 persons SPT was performed simultaneously with five of the allergens using different batches. RESULTS: Thirty percent had at least one positive SPT. Among asthmatics this number was 62%. Only minor differences were seen between the sizes of two weals from the same batch. A second SPT with the same batch did not change the association between rhinitis and sensitization. When performing SPT with two different batches disagreement was observed in 2% (Birch) to 11% (Cat) of the subjects. CONCLUSIONS: Performing SPT twice with the same allergen batch does not enhance the validity of the test, and value of double testing can be questioned. Considerable differences in SPT response with different batches from the same manufacturer were observed. Thus inter batch differences in allergen extracts might be a source of variability

A cross-sectional study of the relation between symptoms and physical findings in computer operators

BACKGROUND: The character of upper limb disorder in computer operators is subject to debate. A peripheral nerve-involvement is suggested from the common presence of a triad of symptoms consisting of pain, paraestesiae and subjective weakness, and from physical findings suggesting neuropathy. This study aimed to examine the outcome of a detailed neurological examination in computer operators and to compare findings with the presence of symptoms. METHODS: 96 graphical computer operators answered a modified Nordic Questionnaire including information on perceived pain in the shoulder, elbow, and wrist/hand scored for each region on a VAS-scale 0 – 9. In addition, they underwent a physical examination including the subjective assessment of the individual function of 11 upper limb muscles, of algesia in five and vibratory threshold in three territories, respectively, and of mechanosensitivity of nerves at seven locations. In order to reflect an involvement of the brachial plexus (chord level), the posterior interosseous nerve and the median nerve at elbow level we defined three patterns of neurological findings illustrating the course of nerves and their innervation. The pain scores summarized for the three upper limb regions (min. = 0, max = 27) in the mouse-operating and contralateral limbs were compared by a Wilcoxon test and the relation to each physical item analyzed by Kendall's rank correlation. The relation of summarized pain to each pattern was studied by application of a test of the trend across ordered groups (patterns). RESULTS: Pain, paraestesiae and subjective weakness was reported for 67, 23, and 7 mouse-operating limbs, respectively, with the summarized pain scores exceeding 4 in 33 limbs. Abnormal physical findings were prevalent. The summarized pain was significantly related to a reduced function in five muscles, to mechanical allodynia at one location and to elevated threshold to vibration in two territories. Brachial plexopathy was diagnosed in 9/2, median neuropathy in 13/5 and posterior interosseous neuropathy in 13/8 mouse operating/contralateral limbs, respectively. The summarized pain was significantly higher in the mouse-operating limbs and in limbs with any of the defined patterns. There was a significant trend between the summarized pain and the summarized scores for the items contained in each pattern. CONCLUSION: This small-scale study of a group of computer-operators currently in work and with no or minor upper limb symptoms has indicated in symptomatic subjects the presence of peripheral nerve-afflictions with specific locations

A cross-sectional study of the upper limb non-neurogenic physical findings in computer operators and their relation to pain and neurological findings

ObjectivesThe character of upper limb disorders in computer operators is subject to debate. While nerve involvement is suggested by the presenceof pain, paresthesia and subjective weakness, these symptoms are mainly interpreted as related to pathologies outside the nervous system. Findings in a previous study involving computer operators indicated peripheral nerve afflictions with specific locations in symptomatic subjects. Based on the same sample, this study addresses the relation of non-neurogenic findings to pain and neurological findings.Material and MethodsOverall, 96 computer operators scored their perceived pain in the neck, shoulder, elbow, and wrist/hand on a Visual Analogue Scale of 0–9. They underwent 2 sets of blinded physical examinations of selected non-neurogenic and neurological items, respectively. The authors analyzed correlations between the scores of each non-neuropathic finding, and a) mean pain scores for each and all regions, and b) scores for neurological patterns reflecting brachial plexopathy, median neuropathy (the elbow), and posterior interosseous neuropathy, respectively, and their combination. Kendall’s rank correlation test was applied for all statistical analyses.ResultsA median pain level of 1 or 0.5 was reported by 80 and 57 participants on the mouse-operating or contralateral side, respectively. Non-neurogenic and neurological findings were frequent. The mean overall pain correlated with palpation soreness of the neck insertions, and of the trapezius and supraspinatus muscles. Neck and elbow pain correlated with palpation soreness at the neck insertions and the lateral epicondyles, respectively. Significant correlations on the mouse-operating side were identified between posterior interosseous neuropathy and lateral epicondyle soreness, and between median neuropathy and any neurological pattern, and trapezius and lateral epicondyle soreness. Conclusions Pain correlated with palpation soreness, which again correlated with the neurological patterns. Palpation soreness may be less significant as a marker of a painful disorder as it correlated no better with regional than with overall pain. The physical examination of computer operators should include a sufficient neurological assessment

Muscle fatigue in relation to forearm pain and tenderness among professional computer users

Abstract Background To examine the hypothesis that forearm pain with palpation tenderness in computer users is associated with increased extensor muscle fatigue. Methods Eighteen persons with pain and moderate to severe palpation tenderness in the extensor muscle group of the right forearm and twenty gender and age matched referents without such complaints were enrolled from the Danish NUDATA study of neck and upper extremity disorders among technical assistants and machine technicians. Fatigue of the right forearm extensor muscles was assessed by muscle twitch forces in response to low frequency (2 Hz) percutaneous electrical stimulation. Twitch forces were measured before, immediately after and 15 minutes into recovery of an extensor isometric wrist extension for ten minutes at 15 % Maximal Voluntary Contraction (MVC). Results The average MVC wrist extension force and baseline stimulated twitch forces were equal in the case and the referent group. After the fatiguing contraction, a decrease in muscle average twitch force was seen in both groups, but the decrease was largest in the referent group: 27% (95% CI 17–37) versus 9% (95% CI -2 to 20). This difference in twitch force response was not explained by differences in the MVC or body mass index. Conclusion Computer users with forearm pain and moderate to severe palpation tenderness had diminished forearm extensor muscle fatigue response. Additional studies are necessary to determine whether this result reflects an adaptive response to exposure without any pathophysiological significance, or represents a part of a causal pathway leading to pain.</p

Placement of electrodes and force transducer in a study of right forearm extensor muscle twitch forces

<p><b>Copyright information:</b></p><p>Taken from "Muscle fatigue in relation to forearm pain and tenderness among professional computer users"</p><p>http://www.occup-med.com/content/2/1/17</p><p>Journal of Occupational Medicine and Toxicology (London, England) 2007;2():17-17.</p><p>Published online 8 Dec 2007</p><p>PMCID:PMC2245952.</p><p></p> A vertical plate to stabilize the distal forearm and wrist region sideways is not shown in order not to hide the transducer

Critical points for an accurate human genome analysis

Item does not contain fulltextNext-generation sequencing is radically changing how DNA diagnostic laboratories operate. What started as a single-gene profession is now developing into gene panel sequencing and whole-exome and whole-genome sequencing (WES/WGS) analyses. With further advances in sequencing technology and concomitant price reductions, WGS will soon become the standard and be routinely offered. Here, we focus on the critical steps involved in performing WGS, with a particular emphasis on points where WGS differs from WES, the important variables that should be taken into account, and the quality control measures that can be taken to monitor the process. The points discussed here, combined with recent publications on guidelines for reporting variants, will facilitate the routine implementation of WGS into a diagnostic setting