Treatment-related changes in serum neutrophil gelatinase-associated lipocalin (NGAL) in psoriatic arthritis: results from the PIPA cohort study

OBJECTIVES

Obesity and psoriatic arthritis (PsA) have a complicated relationship. While weight alone does not cause PsA, it is suspected to cause worse symptoms. Neutrophil gelatinase-associated lipocalin (NGAL) is secreted through various cell types. Our objective was to assess the changes and trajectories in serum NGAL and clinical outcomes in patients with PsA during 12 months of anti-inflammatory treatment.

METHOD

This exploratory prospective cohort study enrolled PsA patients initiating conventional synthetic or biological disease-modifying anti-rheumatic drugs (csDMARDs/bDMARDs). Clinical, biomarker, and patient-reported outcome measures were retrieved at baseline, and 4 and 12 months. Control groups at baseline were psoriasis (PsO) patients and apparently healthy controls. The serum NGAL concentration was quantified by a high-performance singleplex immunoassay.

RESULTS

In total, 117 PsA patients started a csDMARD or bDMARD, and were compared indirectly at baseline with a cross-sectional sample of 20 PsO patients and 20 healthy controls. The trajectory in NGAL related to anti-inflammatory treatment for all included PsA patients showed an overall change of -11% from baseline to 12 months. Trajectories in NGAL for patients with PsA, divided into treatment groups, showed no clear trend in clinically significant decrease or increase following anti-inflammatory treatment. NGAL concentrations in the PsA group at baseline corresponded to the levels in the control groups. No correlation was found between changes in NGAL and changes in PsA outcomes.

CONCLUSION

Based on these results, serum NGAL does not add any value as a biomarker in patients with peripheral PsA, either for disease activity or for monitoring.

Nailfold capillaroscopy as diagnostic test in patients with psoriasis and psoriatic arthritis: A systematic review

Up to 30 % of patients with psoriasis (PsO) develop psoriatic arthritis (PsA), and diagnosis can be difficult. Nailfold capillaroscopy (NC) is an easily applicable, non-invasive procedure to assess skin microcirculation. This systematic review investigates NC as diagnostic tool for PsO and PsA, including correlations between NC outcome measures to clinical and laboratory outcome measures. This systematic review was built on the PICO and PRISMA guidelines. In total 22 relevant studies were found Searching in the Web of Science, PubMed and Embase, latest update June 13th, 2022. The following NC outcome measures are found to be significantly more prevalent in PsO patients than healthy controls: reduced density, reduced length and more abnormal morphology. Likewise, in PsA patients, reduced density, more abnormal morphology, more microhaemorrhages and fewer hairpin shapes are found to be significantly more prevalent. Results were non-conclusive in terms of disease activity and duration with NC findings. Random-effects meta-analysis showed a significant reduction of density in PsO patients compared to healthy controls (studies: 6, n = 249; SMD = -0.91; 95 % CI [-1.41, -0.40], p = 0.0058, heterogeneity I²=74 %, AUC = 0.740) and in PsA patients compared to healthy controls (studies: 5, n = 130; SMD = -1.22; 95 % CI [-2.38, -0.06], p = 0.0432, heterogeneity I²=89 %, AUC = 0.806). No NC outcome measures were overall conclusive in differentiating PsO from PsA. Considering the conflicting results and small sample sizes further large-scale research on the identification of capillaroscopic changes in PsO and PsA and correlations with standardised clinical and laboratory outcome measures are necessary.

Increased prevalence of sleep disturbance in psoriatic arthritis is associated with inflammatory and non-inflammatory measures

OBJECTIVES

To examine the prevalence of sleep disturbances, quantified by the Pittsburgh Sleep Quality Index (PSQI), in patients with psoriatic arthritis (PsA), psoriasis (PsO) and healthy controls (HCs), explore associations between PSQI and clinical and patient-reported outcomes, and evaluate the effect of treatment on PSQI.

METHOD

Patients were included from the Parker Institute's PsA patient cohort to evaluate the prevalence of sleep disturbances. Univariate and multivariate regression analyses were used to explore associations between sleep disturbance and outcome measures. Treatment effect in PsA patients was assessed with a mixed-effect model for repeated measures.

RESULTS

In total, 109 PsA patients, 20 PsO patients, and 20 HCs were included. Sleep disturbances were reported by 66.1% of PsA patients, 45.0% of PsO patients, and 15.0% of HCs. Univariate regression analyses revealed statistically significant associations (p < 0.001) between PSQI and Disease Activity Score (DAS28CRP), tender points, visual analogue scale (VAS) patient global and pain, Psoriatic Arthritis Impact of Disease fatigue, Health Assessment Questionnaire (HAQ), and painDETECT score. Multivariate regression analysis demonstrated VAS patient global, VAS pain, and tender points as being independently associated with PSQI. The mixed-effect model revealed no effect of treatment.

CONCLUSION

More PsA patients than PsO patients and HCs reported sleep disturbances. Sleep disturbances were associated with inflammatory and non-inflammatory measures possibly explaining the limited effect of treatment. This demonstrates the need for interdisciplinary approaches to improve the management of sleep disturbance in PsA.Trial registration: ClinicalTrials.gov (NCT02572700).

2021 international consensus statement on optical coherence tomography for basal cell carcinoma: image characteristics, terminology and educational needs

BACKGROUND

Despite the widespread use of optical coherence tomography (OCT) for imaging of keratinocyte carcinoma, we lack an expert consensus on the characteristic OCT features of basal cell carcinoma (BCC), an internationally vetted set of OCT terms to describe various BCC subtypes, and an educational needs assessment.

OBJECTIVES

To identify relevant BCC features in OCT images, propose terminology based on inputs from an expert panel and identify content for a BCC-specific curriculum for OCT trainees.

METHODS

Over three rounds, we conducted a Delphi consensus study on BCC features and terminology between March and September 2020. In the first round, experts were asked to propose BCC subtypes discriminable by OCT, provide OCT image features for each proposed BCC subtypes and suggest content for a BCC-specific OCT training curriculum. If agreement on a BCC-OCT feature exceeded 67%, the feature was accepted and included in a final review. In the second round, experts had to re-evaluate features with less than 67% agreement and rank the ten most relevant BCC OCT image features for superficial BCC, nodular BCC and infiltrative and morpheaphorm BCC subtypes. In the final round, experts received the OCT-BCC consensus list for a final review, comments and confirmation.

RESULTS

The Delphi included six key opinion leaders and 22 experts. Consensus was found on terminology for three OCT BCC image features: (i) hyporeflective areas, (ii) hyperreflective areas and (iii) ovoid structures. Further, the participants ranked the ten most relevant image features for nodular, superficial, infiltrative and morpheaform BCC. The target group and the key components for a curriculum for OCT imaging of BCC have been defined.

CONCLUSION

We have established a set of OCT image features for BCC and preferred terminology. A comprehensive curriculum based on the expert suggestions will help implement OCT imaging of BCC in clinical and research settings.

POS0144 NOVEL APPLICATION OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY AND NAILFOLD CAPILLAROSCOPY IN PSORIATIC ARTHRITIS - DIAGNOSTIC AND PROGNOSTIC ACCURACY IN RELATION TO PSORIASIS AND HAND OSTEOARTHRITIS

Background:

Nailfold video capillaroscopy (NVC) and angiographic optical coherence tomography (OCTA) have potential in diagnosing psoriatic arthritis (PsA) and differentiating it from psoriasis vulgaris (PsO) and hand osteoarthritis (OA).

Objectives:

To assess the diagnostic properties of NVC and OCTA in patients with PsA compared to patients with PsO and hand OA based on nailfold capillary patterns.

Methods:

Patients with distal interphalangeal-joint PsA and nail involvement (n=50), PsO with nail involvement (n=12); and OA (n=13) were included in this cross-sectional study. Capillaries were evaluated semi-quantitatively and qualitatively. Differences in capillary findings between groups were assessed using mixed linear models. Binary logistic regression analyses were performed to determine the probability for PsA diagnosis based on capillaroscopy findings.

Results:

Reduced capillary density and reduced nailfold blood flow in OCTA images distinguished PsA from both PsO (p=0.004 and p=0.052) and OA (p=0.024 and p<0.001). Qualitative analysis revealed that glomerular capillaries were found in only 3% of PsA patients but in 13% of PsO patients (P=0.003). Furthermore, coiled vessels were only seen in 55% of PsA patients and 71% in PsO patients (P=0.043). NVC microhaemorrhage was dominant in PsA patients (13 % and 17 %) and significantly different to OA patients (p=0.05). No capillary pattern was associated with an increased probability of the PsA diagnosis.

Conclusion:

A pathognomic pattern for PsA diagnosis was not identified, however we demonstrated characteristics significant capillaroscopy findings for PsA such as decreased capillary density, reduced blood flow, and less coiled vessels in OCTA and presence of NVC microhemorrhages.

Table 1.NVC-ratingPsA (n=188)PsO (n=42)OA (n=48)PsA vs PsOPsA vs OANVC ad modum CutoloReduced capillary density51 %31 %51 %P=0.1070.770Irregularly enlarged capillaries22 %33 %25 %P=0.082P=0.988Giant capillary2 %00P=0.400P=0.375Microhaemorrhages13 %7 %2 %P=0.327P=0.05Capillary ramifications14 %24 %29 %P=0.054P=0.307Capillary disorganisation45 %57 %48 %P=0.170P=0.685OCTA-ratingPsA n=193PsO n=48OA n=52PsA vs PsOPsA vs OAOCTA ad modum CutoloReduced capillary density53 %21 %33 %P=0.004P=0.024Irregularly enlarged capillaries34 %56 %19 %p=0.015P=0.178Giant capillary000--Microhaemorrhages000--Capillary ramifications000--Capillary disorganisation55 %46 %49 %P=0.2090.723OCTNail thickness*, mm., mean (SD)0.62 (0.13)0.73 (0.39)0.59 (0.08)p=0.876P=0.020OCTA blood flow percentage, mean (SD)6.00 (2.94)6.94 (3.08)7.88 (3.30)P=0.052P<0.001Capillary morphologyPsA n=192PsO n=48OA n=52PsA vs PsOPsA vs OAQualitative evaluation of NVC morphologyTortuous/Coiled capillaries55 %71 %56 %P=0.043P=0.890Enlarged capillary diameter17 %21 %17 %P=0.557P=0.984Ramified capillaries13 %15 %19 %P=0.701P=0.215Microhaemorrhages17 %6 %8 %P=0.068P=0.106Elongated capillaries6 %4 %4 %P=0.669P=0.592Different capillary shapes, glomerular3 %13 %2 %P=0.003P=0.779

The distribution of NVC and OCTA capillary morphology between PsA, PsO and OA, and qualitative evaluation of NVC morphology. Data are presented as percentage of capillary findings within the group. Differences between PsA and the other groups are presented as p-values. PsA: psoriatic arthritis, PsO: psoriasis vulgaris, OA: hand osteoarthritis, NVC nailfold video capillaroscopy, OCTA: angiographic optical coherence tomography. *: 1 patient (PsO group) was excluded from the analysis because of nail thickness>2.0 mm exceeding the maximum penetration depth of the OCT laser, representing an outlier.

Figure 1.

Optical coherence tomography angiography of the nail and nailbed blood vessels in patients with psoriatic arthritis, psoriasis, and hand osteoarthritis. *: nail plate. ¤: cuticle. #: proximal nailfold. §: one-millimetre field.

Acknowledgements:

The data-analysis of blood flow in angiographic OCT images was kindly performed as a batch analysis by CEO Jon Holmes, Michelson Diagnostics Ltd., Kent.

Disclosure of Interests:

Jørgen Guldberg-Møller Speakers bureau: AbbVie, NOVARTIS, Eli-Lilly and BK Ultrasound outside the present work., Tanja Schjødt Jørgensen Speakers bureau: AbbVie, Pfizer, Roche, Novartis, UCB, Biogen and Eli Lilly., Consultant of: AbbVie, Pfizer, Roche, Novartis, UCB, Biogen and Eli Lilly., Marius Henriksen Consultant of: Advisory Board member of Thuasne Group, France, Karen Ellegaard: None declared, Mette Mogensen: None declared, Lars Erik Kristensen Speakers bureau: Pfizer, AbbVie, Amgen, UCB, Gilead, Biogen, BMS, MSD, Novartis, Eli Lilly, and Janssen pharmaceuticals., Consultant of: Pfizer, AbbVie, Amgen, UCB, Gilead, Biogen, BMS, MSD, Novartis, Eli Lilly, and Janssen pharmaceuticals.

AB0554 SLEEP QUALITY IN PATIENTS WITH PSORIATIC ARTHRITIS

Background:

Psoriatic arthritis (PsA) is a chronic immune-mediated inflammatory disease. It has a heterogeneous clinical presentation with main features being joint swelling and pain, skin and nail psoriasis, enthesitis, and dactylitis. Self-reported outcomes such as quality of sleep and fatigue are often neglected topics although having great impact on patients’ everyday lives.

Objectives:

The primary objective was to analyze the prevalence of PsA patients suffering from poor quality of sleep, defined by Pittsburgh Sleep Quality Index (PSQI) score ≥ 5, and to study the association between being a good or poor sleeper and clinical- and patient-reported outcomes.

Secondary, the effects on outcomes after initiation of treatment.

Methods:

Patient characteristics, disease activity and self-reported outcomes were obtained from the PIPA cohort. To evaluate the primary objective, a cross-sectional analysis was conducted including PSQI score at baseline and corresponding data. Patients were divided into two groups, defined as good or poor sleepers (Table 1).

Data from initiation of treatment (baseline) and 4 months follow-up were included when assessing the effect of treatment. Transition of good and poor sleepers from baseline to 4 months follow-up was depicted by a chi-squared test.

A crosstab analysis was performed with baseline PSQI and whether they had widespread pain to investigate a possible link, additionally a Mann-Whitney U test.

Results:

From January 2018-November 2020 a total of 109 patients were included. The prevalence of PsA patients suffering from poor quality of sleep at baseline were 66.1% whereas the remaining 33.9% were deemed good sleepers.

There was no statistically significant difference in patient demographics when comparing good and poor sleepers at baseline. There was a statistically significant difference in patient-reported outcomes such as Visual Analogue Scale (VAS) pain, VAS global, Health Assessment Questionnaire (HAQ) score and Disease Activity Score (DAS28-CRP), with poor sleepers scoring higher.

57 patients had complete data at 4 months follow-up. At baseline 71.9% of them were classified as poor sleepers (Figure 1). A chi-squared test presented the transition at 4 months follow-up. 47.4% of the patients were now classified as poor sleepers.

While 27 poor sleepers became good sleepers, 13 good sleepers became poor sleepers, with data being statistically significant (p 0.001).

The crosstab analysis exposed 75 patients without widespread pain (mean 7.13±3.79) and 31 patients with widespread pain (mean 9.52±4.93).

Baseline PSQI and whether the patients had widespread pain was statistically significant (p 0.018).

Conclusion:

Overall, PsA patients with poor quality of sleep have higher levels in terms of self-reported pain and disease activity.

The amount of good sleepers after 4 months increased, but there was a negative transition of patients going from good to poor sleepers. This could indicate that more factors are important for quality of sleep, e.g. sociopsychological aspects like anxiety, depression, ability to work.

Table 1.

Patient characteristics

Totaln = 109Good sleepersPSQI ≤ 5n = 37Poor sleepersPSQI > 5n = 72nnpFemale, n (%)65 (59.4%)19 (51.4%)3746 (63.9%)720.206Age, yrs53.9 (45.4-62.25)60.4 (45.5-65.2)3751.5 (44.7-59.95)720.144Disease duration, yrs3.86 (1.0-11.0)4.5 (1.04-11.06)342.91 (1.0-10.75)680.352csDMARD, n (%)71 (65.1%)26 (70.2%)3745 (62.5%)720.420bDMARD, n (%)70 (64.2%)24 (64.8%)3746 (63.9%)720.920Patient pain assessment0-100 mm VAS50.0 (21.0-74.5)27.0 (9.0-60.5)3763.5 (32.25-78.0)72<0.001Patient global assessment0-100 mm VAS61.0 (27.5-78.5)35.0 (17.5-59.0)3769.5 (50.0-85.75)72<0.001PsAID fatigue6.0 (3.0-8.0)4.0 (2.5-7.0)376.5 (4.0-8.0)720.488HAQ score, 0-30.75 (0.38-1.25)0.38 (0.25-0.81)370.88 (0.63-1.38)72<0.001PASI1.7 (0.0-9.75)2.0 (0.0-7.3)351.2 (0.0-11.5)650.940DAS28-CRP3.77 (3.02-4.58)3.44 (2.65-3.94)374.07 (3.28-4.93)720.001

Disclosure of Interests:

Peter Benzin: None declared., Zara Rebecca Stisen: None declared., Marie Skougaard: None declared., Tanja Schjødt Jørgensen Speakers bureau: Received consulting fees and/or speaking fees from AbbVie, Pfizer, Roche, Novartis, UCB, Biogen and Eli Lilly, Consultant of: Received consulting fees and/or speaking fees from AbbVie, Pfizer, Roche, Novartis, UCB, Biogen and Eli Lilly, Rebekka L. Hansen: None declared., Lourdes M. Perez-Chada: None declared., Mette Mogensen: None declared., Joseph F. Merola Consultant of: Consultant and/or investigator for Merck, Bristol-Myers Squibb, AbbVie, Dermavant, Eli Lilly, Novartis, Janssen, UCB, Sanofi, Regeneron, Arena, Sun Pharma, Biogen, Pfizer, EMD Sorono, Avotres and Leo Pharma., Lars Erik Kristensen Speakers bureau: Received fees for speaking and consultancy from Pfizer, AbbVie, Amgen, UCB, Gilead, Biogen, BMS, MSD, Novartis, Eli Lilly, and Janssen pharmaceuticals., Consultant of: Received fees for speaking and consultancy from Pfizer, AbbVie, Amgen, UCB, Gilead, Biogen, BMS, MSD, Novartis, Eli Lilly, and Janssen pharmaceuticals.

In vivo characterization of pustules in Malassezia Folliculitis by reflectance confocal microscopy and optical coherence tomography. A case series study

BACKGROUND AND OBJECTIVE

Malassezia Folliculitis (MaF) is an inflammatory condition of hair follicles caused by Malassezia yeast. Optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) are imaging technologies enabling in vivo visualization of superficial skin layers. This study explores morphology of pustules in MaF imaged by OCT and RCM.

METHODS

Patients with microscopically verified MaF were included in this case series. Morphology was evaluated qualitatively with RCM and OCT, focusing on shape, border and content of selected pustules.

RESULTS

Nine patients with MaF were included. Clinically, six patients presented monomorphic MaF with multiple superficial pustules, while three patients showed more polymorph MaF appearance. In total 13 pustules were investigated by RCM and OCT. In RCM images, pustules varied from having a well-defined border with homogenous content to ill-defined borders with heterogeneous content. A distinct black halo was occasionally observed around pustules as were dilated vessels. In OCT images, pustules appeared polymorphic, showing both well- and ill-defined structures with oval or irregular shape and more or less homogenous content. Malassezia fungi were not discernible by either RCM or OCT. Specific morphological image features in RCM and OCT did not reflect different clinical manifestations of MaF.

CONCLUSION

RCM and OCT images identify morphological aspects of MaF pustules, and confirm that MaF is a folliculitis with clinical as well as morphological variance.

Imaging of collagen deposition disorders using optical coherence tomography

BACKGROUND

Collagen deposition disorders such as hypertrophic scars, keloids and scleroderma can be associated with significant stigma and embarrassment. These disorders often constitute considerable impairment to quality of life, with treatment posing to be a substantial challenge. Optical coherence tomography (OCT) provides a non-invasive, easily applicable bedside optical imaging method for assessment of the skin. It is hypothesized that OCT imaging may be useful in assessing fibrosis to avoid additional biopsies that could potentially worsen the scarring.

METHOD

Thirty-three patients with ordinary scars, hypertrophic scars, keloid scarring, lichen sclerosus et atrophicus and localized or systemic scleroderma were recruited for this pilot study. Affected tissue and adjacent healthy skin were scanned using OCT and digitally photographed. Density measurements were performed in ImageJ on OCT images from scleroderma patients, both systemic and morphea (10 patients), keloid patients (10 patients) and healthy skin adjacent to keloids (10 patients).

RESULTS

OCT images of scarring diseases showed varying degrees of disruption to the skin architecture. OCT characteristics were identified for each lesion type. Hypertrophic scars displayed an increased vascularity and signal-rich bands correlating to excessive collagen deposition. Keloids depicted a disarray of hyper-reflective areas primarily located in the upper dermis. Additionally, the dermis displayed a heterogeneous morphology without indications of any vascular supply or lymphatic network. In contrast to keloids, scleroderma displayed a more cohesive backscattering indicating a difference in density of collagen or other dermal structures. OCT images demonstrated no significant differences between mean density measurements in OCT images of scleroderma, keloid and healthy skin (P = 0.07).

CONCLUSION

The OCT imaging appears to identify different scarring mechanisms, and therefore be of potential use in the assessment of outcomes following non-invasive therapy of e.g. early or progressive lesions.

High temperature and pressure electrochemical test station

An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 °C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established test station is provided.

Maximal lipid oxidation in patients with type 2 diabetes is normal and shows an adequate increase in response to aerobic training

AIM

Insulin resistance in subjects with type 2 diabetes (T2D) and obesity is associated with an imbalance between the availability and the oxidation of lipids. We hypothesized that maximal whole-body lipid oxidation during exercise (FATmax) is reduced and that training-induced metabolic adaptation is attenuated in T2D.

METHODS

Obese T2D (n = 12) and control (n = 11) subjects matched for age, sex, physical activity and body mass index completed 10 weeks of aerobic training. Subjects were investigated before and after training with maximal and submaximal exercise tests and euglycaemic-hyperinsulinaemic clamps combined with muscle biopsies.

RESULTS

Training increased maximal oxygen consumption (VO(2max)) and muscle citrate synthase activity and decreased blood lactate concentrations during submaximal exercise in both groups (all p < 0.01). FATmax increased markedly (40-50%) in both T2D and control subjects after training (all p < 0.001). There were no significant differences in these variables and lactate threshold (%VO(2max)) between groups before or after training. Insulin-stimulated glucose disappearance rate (Rd) was lower in T2D vs. control subjects both before and after training. Rd increased in response to training in both groups (all p < 0.01). There was no correlation between Rd and measures of oxidative capacity or lipid oxidation during exercise or the training-induced changes in these parameters.

CONCLUSIONS

FATmax was not reduced in T2D, and muscle oxidative capacity increased adequately in response to aerobic training in obese subjects with and without T2D. These metabolic adaptations to training seem to be unrelated to changes in insulin sensitivity and indicate that an impaired capacity for lipid oxidation is not a major cause of insulin resistance in T2D.

Nail thickness measurements using optical coherence tomography and 20-MHz ultrasonography

BACKGROUND

Nail diseases are often troubling to the patient and may present a diagnostic challenge to the dermatologist. Biopsies from the nail may be required although often perceived uncomfortable by the patient and potentially scarring. Noninvasive technologies are therefore of particular interest in the study of nails. Optical coherence tomography (OCT) is an optical imaging modality which may provide improved data.

OBJECTIVES

This study evaluates nail morphology and thickness in OCT images in comparison with high-frequency ultrasound (HFUS) imaging of the nail.

METHODS

Ten healthy volunteers were recruited for imaging and nail measurements; OCT and HFUS images were compared qualitatively. Nail thickness measurements with four different techniques were compared: ultrasound, OCT, polarization-sensitive (PS) OCT and callipers. The OCT system was developed at Risoe National Laboratory, Denmark. A commercially available 20-MHz ultrasound system (Dermascan; Cortex Technology, Hadsund, Denmark) was used.

RESULTS

In standard OCT the nail plate appeared as a layered structure containing a varying number of horizontal homogeneous bands of varying intensity and thickness. PS-OCT images of the nail plate also showed a layered structure. The refractive index of the nail was 1.47 +/- 0.09. OCT and PS-OCT had low coefficients of variation, 6.31 and 6.53, respectively, compared with other methods: HFUS 12.70 and callipers 14.03.

CONCLUSION

PS-OCT has to our knowledge not been applied to OCT analysis of the nail, and offers some advantages in separation of the nail bed from the nail plate.

The potential for mitochondrial fat oxidation in human skeletal muscle influences whole body fat oxidation during low-intensity exercise

The purpose of this study was to investigate fatty acid (FA) oxidation in isolated mitochondrial vesicles (mit) and its relation to training status, fiber type composition, and whole body FA oxidation. Trained (Vo(2 peak) 60.7 +/- 1.6, n = 8) and untrained subjects (39.5 +/- 2.0 ml.min(-1).kg(-1), n = 5) cycled at 40, 80, and 120 W, and whole body relative FA oxidation was assessed from respiratory exchange ratio (RER). Mit were isolated from muscle biopsies, and maximal ADP stimulated respiration was measured with carbohydrate-derived substrate [pyruvate + malate (Pyr)] and FA-derived substrate [palmitoyl-l-carnitine + malate (PC)]. Fiber type composition was determined from analysis of myosin heavy-chain (MHC) composition. The rate of mit oxidation was lower with PC than with Pyr, and the ratio between PC and Pyr oxidation (MFO) varied greatly between subjects (49-93%). MFO was significantly correlated to muscle fiber type distribution, i.e., %MHC I (r = 0.62, P = 0.03), but was not different between trained (62 +/- 5%) and untrained subjects (72 +/- 2%). MFO was correlated to RER during submaximal exercise at 80 (r = -0.62, P = 0.02) and 120 W (r = -0.71, P = 0.007) and interpolated 35% Vo(2 peak) (r = -0.74, P = 0.004). ADP sensitivity of mit respiration was significantly higher with PC than with Pyr. It is concluded that MFO is influenced by fiber type composition but not by training status. The inverse correlation between RER and MFO implies that intrinsic mit characteristics are of importance for whole body FA oxidation during low-intensity exercise. The higher ADP sensitivity with PC than that with Pyr may influence fuel utilization at low rate of respiration.

Mitochondrial efficiency in rat skeletal muscle: influence of respiration rate, substrate and muscle type

AIM

To investigate the hypothesis that mitochondrial efficiency (i.e. P/O ratio) is higher in type I than in type II fibres during submaximal rates of respiration.

METHODS

Mitochondria were isolated from rat soleus and extensor digitorum longus (EDL) muscles, representing type I and type II fibres, respectively. Mitochondrial efficiency (P/O ratio) was determined with pyruvate (Pyr) or palmitoyl-l-carnitine (PC) during submaximal (constant rate of adenosine diphosphate infusion) and maximal (V(max), state 3) rates of respiration and fitted to monoexponential functions.

RESULTS

There was no difference in V(max) between PC and Pyr in soleus but in EDL V(max) with PC was only 58% of that with Pyr. The activity of 3-hydroxyacyl-CoA dehydrogenase was threefold higher in soleus than in EDL. P/O ratio at V(max) was 8-9% lower with PC [2.33 +/- 0.02 (soleus) and 2.30 +/- 0.02 (EDL)] than with Pyr [2.52 +/- 0.03 (soleus) and 2.54 +/- 0.03 (EDL)] but not different between the two muscles (P > 0.05). P/O ratio was low at low rates of respiration and increased exponentially when the rate of respiration increased. The asymptotes of the curves were similar to P/O ratio at V(max). P/O ratio at submaximal respirations was not different between soleus and EDL neither with Pyr nor with PC.

CONCLUSION

Mitochondrial efficiency, as determined in vitro, was not significantly different in the two fibre types neither at V(max) nor at submaximal rates of respiration. The low V(max) for PC oxidation in EDL may relate to low activity of beta-oxidation.

Cycling efficiency in humans is related to low UCP3 content and to type I fibres but not to mitochondrial efficiency

The purpose of this study was to investigate the hypothesis that cycling efficiency in vivo is related to mitochondrial efficiency measured in vitro and to investigate the effect of training status on these parameters. Nine endurance trained and nine untrained male subjects (V(O2peak) = 60.4 +/- 1.4 and 37.0 +/- 2.0 ml kg(-1) min(-1), respectively) completed an incremental submaximal efficiency test for determination of cycling efficiency (gross efficiency, work efficiency (WE) and delta efficiency). Muscle biopsies were taken from m. vastus lateralis and analysed for mitochondrial respiration, mitochondrial efficiency (MEff; i.e. P/O ratio), UCP3 protein content and fibre type composition (% MHC I). MEff was determined in isolated mitochondria during maximal (state 3) and submaximal (constant rate of ADP infusion) rates of respiration with pyruvate. The rates of mitochondrial respiration and oxidative phosphorylation per muscle mass were about 40% higher in trained subjects but were not different when expressed per unit citrate synthase (CS) activity (a marker of mitochondrial density). Training status had no influence on WE (trained 28.0 +/- 0.5, untrained 27.7 +/- 0.8%, N.S.). Muscle UCP3 was 52% higher in untrained subjects, when expressed per muscle mass (P < 0.05 versus trained). WE was inversely correlated to UCP3 (r = -0.57, P < 0.05) and positively correlated to percentage MHC I (r = 0.58, P < 0.05). MEff was lower (P < 0.05) at submaximal respiration rates (2.39 +/- 0.01 at 50% V(O2max)) than at state 3 (2.48 +/- 0.01) but was neither influenced by training status nor correlated to cycling efficiency. In conclusion cycling efficiency was not influenced by training status and not correlated to MEff, but was related to type I fibres and inversely related to UCP3. The inverse correlation between WE and UCP3 indicates that extrinsic factors may influence UCP3 activity and thus MEff in vivo.

Advanced anodes for high-temperature fuel cells

Fuel cells will undoubtedly find widespread use in this new millennium in the conversion of chemical to electrical energy, as they offer very high efficiencies and have unique scalability in electricity-generation applications. The solid-oxide fuel cell (SOFC) is one of the most exciting of these energy technologies; it is an all-ceramic device that operates at temperatures in the range 500-1,000 degrees C. The SOFC offers certain advantages over lower temperature fuel cells, notably its ability to use carbon monoxide as a fuel rather than being poisoned by it, and the availability of high-grade exhaust heat for combined heat and power, or combined cycle gas-turbine applications. Although cost is clearly the most important barrier to widespread SOFC implementation, perhaps the most important technical barriers currently being addressed relate to the electrodes, particularly the fuel electrode or anode. In terms of mitigating global warming, the ability of the SOFC to use commonly available fuels at high efficiency, promises an effective and early reduction in carbon dioxide emissions, and hence is one of the lead new technologies for improving the environment. Here, we discuss recent developments of SOFC fuel electrodes that will enable the better use of readily available fuels.

Experimental microgyri disrupt the barrel field pattern in rat somatosensory cortex

Transcranial freeze lesions in neonatal rat pups produce microgyri and adjacent epileptogenic regions of neocortex that can be used to model human polymicrogyria. The hypothesis that the presence of microgyri is associated with abnormal cortical organization occurring within as well as adjacent to the microgyri was tested by creating microgyri within the face representation of somatosensory cortex. Microgyri were associated with a widespread disruption of the stereotypic whisker barrel field pattern delineated with cytochrome oxidase (CO) staining. CO-stained patches resembling barrel hollows were absent within the microgyrus, and were abnormally shaped and distributed outside of the microgyrus. Adjacent Nissl- or acetylcholinesterase-stained sections demonstrated that both cell clusters and thalamocortical afferents contributed to the abnormally organized paramicrogyral zone identified in CO-stained sections. Field potential recordings showed that this region of heavy CO staining corresponded to the epileptogenic zone adjacent to the microgyrus. Results support our hypothesis that the epileptogenic paramicrogyral zone develops an abnormal organization of cell clusters and thalamocortical projections that could contribute to epileptogenesis in the paramicrogyral zone.

[Lymphedema in patients treated for breast cancer. A cross-sectional study in the county of Ribe. The need of manual lymph drainage; risk factors]

Over a period of three months circumferences of the upper and lower arm were measured in 334 patients previously treated for breast cancer. Lymphoedema was found in 25 (7.5%) of these patients. The total number of patients with breast cancer who had lymphoedema in one year in Ribe Amt was calculated to 40. As more than one half of the patients only had modest or no subjective symptoms, it is expected that about 20 patients pr. year need manual lymph drainage, and about 20 patients need prophylactic physiotherapy. It was found that the risk for increased circumference of the upper arm was correlated to axillary radiotherapy and the total number of lymph nodes removed from the axilla. The risk of increased circumference of the lower arm was correlated to chemotherapy.