Estimating motor unit numbers from a CMAP scan: Repeatability study on three muscles at 15 centres.

OBJECTIVE: To assess the repeatability and suitability for multicentre studies of MScanFit motor unit number estimation (MUNE), which involves modelling compound muscle action potential (CMAP) scans. METHODS: Fifteen groups in 9 countries recorded CMAP scans twice, 1-2 weeks apart in healthy subjects from abductor pollicis brevis (APB), abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. The original MScanFit program (MScanFit-1) was compared with a revised version (MScanFit-2), designed to accommodate different muscles and recording conditions by setting the minimal motor unit size as a function of maximum CMAP. RESULTS: Complete sets of 6 recordings were obtained from 148 subjects. CMAP amplitudes differed significantly between centres for all muscles, and the same was true for MScanFit-1 MUNE. With MScanFit-2, MUNE differed less between centres but remained significantly different for APB. Coefficients of variation between repeats were 18.0% for ADM, 16.8% for APB, and 12.1% for TA. CONCLUSIONS: It is recommended for multicentre studies to use MScanFit-2 for analysis. TA provided the least variable MUNE values between subjects and the most repeatable within subjects. SIGNIFICANCE: MScanFit was primarily devised to model the discontinuities in CMAP scans in patients and is less suitable for healthy subjects with smooth scans.

Compressive sensing in electrical impedance tomography for breathing monitoring.

OBJECTIVE: Electrical impedance tomography (EIT) is a functional imaging technique in which cross-sectional images of structures are reconstructed based on boundary trans-impedance measurements. Continuous functional thorax monitoring using EIT has been extensively researched. Increasing the number of electrodes, number of planes and frame rate may improve clinical decision making. Thus, a limiting factor in high temporal resolution, 3D and fast EIT is the handling of the volume of raw impedance data produced for transmission and its subsequent storage. Owing to the periodicity (i.e. sparsity in frequency domain) of breathing and other physiological variations that may be reflected in EIT boundary measurements, data dimensionality may be reduced efficiently at the time of sampling using compressed sensing techniques. This way, a fewer number of samples may be taken. APPROACH: Measurements using a 32-electrode, 48-frames-per-second EIT system from 30 neonates were post-processed to simulate random demodulation acquisition method on 2000 frames (each consisting of 544 measurements) for compression ratios (CRs) ranging from 2 to 100. Sparse reconstruction was performed by solving the basis pursuit problem using SPGL1 package. The global impedance data (i.e. sum of all 544 measurements in each frame) was used in the subsequent studies. The signal to noise ratio (SNR) for the entire frequency band (0 Hz-24 Hz) and three local frequency bands were analysed. A breath detection algorithm was applied to traces and the subsequent error-rates were calculated while considering the outcome of the algorithm applied to a down-sampled and linearly interpolated version of the traces as the baseline. MAIN RESULTS: SNR degradation was generally proportional with CR. The mean degradation for 0 Hz-8 Hz (of interest for the target physiological variations) was below ~15 dB for all CRs. The error-rates in the outcome of the breath detection algorithm in the case of decompressed traces were lower than those associated with the corresponding down-sampled traces for CR ⩾ 25, corresponding to sub-Nyquist rate for breathing frequency. For instance, the mean error-rate associated with CR = 50 was ~60% lower than that of the corresponding down-sampled traces. SIGNIFICANCE: To the best of our knowledge, no other study has evaluated the applicability of compressive sensing techniques on raw boundary impedance data in EIT. While further research should be directed at optimising the acquisition and decompression techniques for this application, this contribution serves as the baseline for future efforts.

Clinical performance of a novel textile interface for neonatal chest electrical impedance tomography.

OBJECTIVE: Critically ill neonates and infants might particularly benefit from continuous chest electrical impedance tomography (EIT) monitoring at the bedside. In this study a textile 32-electrode interface for neonatal EIT examination has been developed and tested to validate its clinical performance. The objectives were to assess ease of use in a clinical setting, stability of contact impedance at the electrode-skin interface and possible adverse effects. APPROACH: Thirty preterm infants (gestational age: 30.3 ± 3.9 week (mean ± SD), postnatal age: 13.8 ± 28.2 d, body weight at inclusion: 1727 ± 869 g) were included in this multicentre study. The electrode-skin contact impedances were measured continuously for up to 3 d and analysed during the initial 20-min phase after fastening the belt and during a 10 h measurement interval without any clinical interventions. The skin condition was assessed by attending clinicians. MAIN RESULTS: Our findings imply that the textile electrode interface is suitable for long-term neonatal chest EIT imaging. It does not cause any distress for the preterm infants or discomfort. Stable contact impedance of about 300 Ohm was observed immediately after fastening the electrode belt and during the subsequent 20 min period. A slight increase in contact impedance was observed over time. Tidal variation of contact impedance was less than 5 Ohm. SIGNIFICANCE: The availability of a textile 32-electrode belt for neonatal EIT imaging with simple, fast, accurate and reproducible placement on the chest strengthens the potential of EIT to be used for regional lung monitoring in critically ill neonates and infants.

Strategies for free flap transfer and revascularisation with long-term outcome in the treatment of large diabetic foot lesions.

OBJECTIVE/BACKGROUND: To analyse the impact of ischaemia and revascularisation strategies on the long-term outcome of patients undergoing free flap transfer (FFT) for large diabetic foot lesions penetrating to the tendon, bone, or joint. METHODS: Foot lesions of 63 patients with diabetes (median age 56 years; 70% male) were covered with a FTT in 1991-2003. Three groups were formed and followed until 2009: patients with a native in line artery to the ulcer area (n = 19; group A), patients with correctable ischaemia requiring vascular bypass (n = 32; group B), and patients with uncorrectable ischaemia lacking a recipient vessel in the ulcer area (n = 12; group C). RESULTS: The respective 1, 5, and 10 year amputation free survival rates were 90%, 79%, and 63% in group A; 66%, 25%, and 18% in group B; and 50%, 42%, and 17%, in group C. The respective 1, 5, and 10 year leg salvage rates were 94%, 94%, and 87% in group A; 71%, 65%, and 65% in group B; and 50%, 50%, and 50% in group C. In 1 year, 43%, 45%, and 18% of the patients in groups A, B, and C, respectively, achieved stable epithelisation for at least 6 months. The overall amputation rate was associated with smoking (relative risk [RR] 3.09, 95% confidence interval [CI] 1.8-5.3), heel ulceration (RR 2.25, 95% CI 1.1-4.7), nephropathy (RR 2.24, 95% CI 1.04-4.82), and an ulcer diameter of >10 cm (RR 2.08, 95% CI 1.03-4.48). CONCLUSION: Despite diabetic comorbidities, complicated foot defects may be covered by means of an FFT with excellent long-term amputation free survival, provided that a patent native artery feeds the ulcer area. Ischaemic limbs may also be salvaged with combined FFT and vascular reconstruction in non-smokers and in the absence of very extensive heel ulcers. Occasionally, amputation is avoidable with FFT, even without the possibility of direct revascularisation.

Effect of controlled hypoglycaemia on sympathetic skin response in patients with Type 1 diabetes and control subjects.

AIM: To evaluate the quantity and mechanism of sudomotor function during euglycaemia and hypoglycaemia using sympathetic skin responses in patients with Type 1 diabetes and control subjects. METHODS: Sympathetic skin responses were measured in 16 patients with diabetes without neuropathy and in eight control subjects during euglycaemic and hypoglycaemic clamp. RESULTS: During hypoglycaemia, the number of repetitive synchronous sympathetic skin responses significantly increased in both groups (P<0.05), and this increase was significantly associated with the hypoglycaemia and sweating. CONCLUSIONS: During hypoglycaemia the number of repetitive synchronous sympathetic skin responses was related to increased sweating according to the hypoglycaemic symptom score. This is best explained by central nervous system reactions. The sympathetic skin responses of the patients with Type 1 diabetes had a weaker correlation with hypoglycaemia and its symptoms, which was possibly attributable to an adaptation or a dysfunction of the patients' sudomotor pathways.

Excess of miRNA-378a-5p perturbs mitotic fidelity and correlates with breast cancer tumourigenesis in vivo.

BACKGROUND: Optimal expression and proper function of key mitotic proteins facilitate control and repair processes that aim to prevent loss or gain of chromosomes, a hallmark of cancer. Altered expression of small regulatory microRNAs is associated with tumourigenesis and metastasis but the impact on mitotic signalling has remained unclear. METHODS: Cell-based high-throughput screen identified miR-378a-5p as a mitosis perturbing microRNA. Transient transfections, immunofluorescence, western blotting, time-lapse microscopy, FISH and reporter assays were used to characterise the mitotic anomalies by excess miR-378a-5p. Analysis of microRNA profiles in breast tumours was performed. RESULTS: Overexpression of miR-378a-5p induced numerical chromosome changes in cells and abrogated taxol-induced mitotic block via premature inactivation of the spindle assembly checkpoint. Moreover, excess miR-378a-5p triggered receptor tyrosine kinase-MAP kinase pathway signalling, and was associated with suppression of Aurora B kinase. In breast cancer in vivo, we found that high miR-378a-5p levels correlate with the most aggressive, poorly differentiated forms of cancer. INTERPRETATION: Downregulation of Aurora B by excess miR-378a-5p can explain the observed microtubule drug resistance and increased chromosomal imbalance in the microRNA-overexpressing cells. The results suggest that breast tumours may deploy high miR-378a-5p levels to gain growth advantage and antagonise taxane therapy.

Altered TUBB3 expression contributes to the epothilone response of mitotic cells.

BACKGROUND: Epothilones are a novel group of microtubule (mt) targeting cancer drugs that bind to the ß-subunit of the αß-tubulin dimer. Epothilones inhibit cell proliferation and induce cell death by interfering with the normal mt function. In this study, we examined the consequences of altered expression of human ß-tubulin isotypes in terms of the epothilone drug response in human lung and breast cancer cell lines. METHODS: The ß-tubulin isotypes TUBB2A-C, TUBB3 and TUBB were silenced or overexpressed in A549, A549EpoB40 and MCF7 cell lines in the presence or absence of epothilones. The drug effects on cell proliferation, mitosis and mt dynamics were determined using live cell microscopy and immunofluorescence assays. RESULTS: Loss of TUBB3 enhanced the action of epothilones. TUBB3 knockdown increased the severity of drug-induced mitotic defects and resulted in stabilisation of the mt dynamics in cells. Moreover, exogenous expression of TUBB3 in the epothilone resistant cell line conferred the response to drug treatments. In contrast, reduced levels of TUBB2A-C or TUBB had not apparent effect on the cells' response to epothilones. CONCLUSION: Our results show that the expression of TUBB3 contributes to the cellular response to epothilones, putatively by having an impact on the mt dynamics.

The relationship of pre- and postoperative median and ulnar nerve conduction measures to a self-administered questionnaire in carpal tunnel syndrome.

STUDY AIMS: Following carpal tunnel release (CTR), only very modest correlations have been found between subjective symptoms and function indexes compared to neurophysiological measures. The objective of this study was to evaluate this relationship by comparing the self-administered Boston symptom severity score and function severity score questionnaire against nerve conduction studies (NCS) before and after CTR using two different electrophysiological techniques. PATIENTS AND METHODS: Carpal tunnel release was performed in 51 patients (62 hands). Pre- and postoperative NCS were evaluated using both conventional neurophysiological methods and by means of a new hand-held device. RESULTS: Preoperatively there was almost no correlation between symptom severity and function scores and NCS results. Following surgery however, both symptom severity and function showed a modest, but significant improvement in their correlation to NCS (at highest r=0.405, P<0.01). This improvement in the relation of subjective measures to neurophysiological results was seen in both median nerve sensory and motor conduction as well as in ulnar nerve motor conduction. CONCLUSIONS: In addition to median-nerve dysfunction, it might be suggested that ulnar nerve changes can contribute to symptoms of carpal tunnel syndrome in patients. Several associations were found using a median-ulnar sensory latency difference in the finger-wrist segment and a sensory conduction difference in the palm to wrist segment. Significant correlations were established by both conventional NCS and the new hand-held device.

Identification of fibroblast growth factor-8b target genes associated with early and late cell cycle events in breast cancer cells.

Fibroblast growth factor-8 (FGF-8) is implicated in the development and progression of breast cancer and its levels are frequently elevated in breast tumors. The mechanisms driving FGF-8-mediated tumorigenesis are not well understood. Herein we aimed to identify target genes associated with FGF-8b-mediated breast cancer cell proliferation by carrying out a cDNA microarray analysis of genes expressed in estrogen receptor negative S115 breast cancer cells treated with FGF-8b for various time periods in comparison with those expressed in non-treated cells. Gene and protein expression was validated for selected genes by qPCR and western blotting respectively. Furthermore, using TRANSBIG data, the expression of human orthologs of FGF-8-regulated genes was correlated to the Nottingham prognostic index and estrogen receptor status. The analysis revealed a number of significantly up- and down-regulated genes in response to FGF-8b at all treatment times. The most differentially expressed genes were genes related to cell cycle regulation, mitosis, cancer, and cell death. Several key regulators of early cell cycle progression such as Btg2 and cyclin D1, as well as regulators of mitosis, including cyclin B, Plk1, survivin, and aurora kinase A, were identified as novel targets for FGF-8b, some of which were additionally shown to correlate with prognosis and ER status in human breast cancer. The results suggest that in stimulation of proliferation FGF-8b not only promotes cell cycle progression through the G1 restriction point but also regulates key proteins involved in chromosomal segregation during mitosis and cytokinesis of breast cancer cells.

Clindamycin vs. first-generation cephalosporins for acute osteoarticular infections of childhood--a prospective quasi-randomized controlled trial.

No sufficiently powered trial has examined two antimicrobials in acute osteoarticular infections of childhood. We conducted a prospective, multicentre, quasi-randomized trial in Finland, comparing clindamycin with first-generation cephalosporins. The age of patients ranged between 3 months and 15 years, and all cases were culture-positive. We assigned antibiotic treatment intravenously for the first 2-4 days, and continued oral treatment with clindamycin 40 mg/kg/24 h or first-generation cephalosporin 150 mg/kg/24 h in four doses. Surgery was kept to a minimum. Subsiding symptoms and signs and normalization of C-reactive protein (CRP) level were preconditions for the discontinuation of antimicrobials. The main outcome was full recovery without further antimicrobials because of an osteoarticular indication during 12 months after therapy. The intention-to-treat analysis comprised 252 children, 169 of whom were analysed per-protocol: 82 cases of osteomyelitis, 80 of septic arthritis, and seven of osteomyelitis-arthritis. Staphylococcus aureus strains (all methicillin-sensitive) caused 84% of the cases. Except for one non-serious sequela during convalescence in both groups, and two late infections caused by dissimilar agents in one child, all patients recovered. The entire courses (medians) of clindamycin and cephalosporin lasted for 23 and 24 days, respectively. CRP normalized in both groups in 9 days. The patients were discharged, on average, on day 10. Loose stools were reported less often (1%) in the clindamycin group than in the cephalosporin group (7%), but two clindamycin recipients developed rash. Clindamycin or a first-generation cephalosporin, administered mostly orally, perform equally well in childhood osteoarticular infections, provided that high doses and administration four times daily are used. As most methicillin-resistant staphylococci remain clindamycin-sensitive, clindamycin remains an option instead of costly alternatives.

Chipster: user-friendly analysis software for microarray and other high-throughput data.

BACKGROUND: The growth of high-throughput technologies such as microarrays and next generation sequencing has been accompanied by active research in data analysis methodology, producing new analysis methods at a rapid pace. While most of the newly developed methods are freely available, their use requires substantial computational skills. In order to enable non-programming biologists to benefit from the method development in a timely manner, we have created the Chipster software. RESULTS: Chipster (http://chipster.csc.fi/) brings a powerful collection of data analysis methods within the reach of bioscientists via its intuitive graphical user interface. Users can analyze and integrate different data types such as gene expression, miRNA and aCGH. The analysis functionality is complemented with rich interactive visualizations, allowing users to select datapoints and create new gene lists based on these selections. Importantly, users can save the performed analysis steps as reusable, automatic workflows, which can also be shared with other users. Being a versatile and easily extendable platform, Chipster can be used for microarray, proteomics and sequencing data. In this article we describe its comprehensive collection of analysis and visualization tools for microarray data using three case studies. CONCLUSIONS: Chipster is a user-friendly analysis software for high-throughput data. Its intuitive graphical user interface enables biologists to access a powerful collection of data analysis and integration tools, and to visualize data interactively. Users can collaborate by sharing analysis sessions and workflows. Chipster is open source, and the server installation package is freely available.

Serum immunoglobulin A concentration in infancy, but not human milk immunoglobulin A, is associated with subsequent atopic manifestations in children and adolescents: a 20-year prospective follow-up study.

BACKGROUND: Serum and secretory IgA concentrations have been suggested to be inversely associated with allergic symptoms in children. Furthermore, low maternal milk IgA concentration has been suggested to be associated with the development of cow's milk allergy. OBJECTIVE: Our aim was to explore whether the serum IgA concentrations in infancy and the IgA concentration of maternal milk predict atopic manifestations in childhood and up to age 20 years. METHODS: A cohort of 200 unselected full-term newborns was prospectively followed up from birth to age 20 years with measurement of serum total IgA at ages 2 and 6 months. The mothers were encouraged to maintain exclusive breastfeeding for as long as possible. Total IgA concentration of maternal milk was measured at birth (colostrum, n=169) and at 2 (n=167) and 6 (n=119) months of lactation. The children were re-assessed at ages 5, 11 and 20 years for the occurrence of allergic symptoms, with skin prick testing and measurement of serum IgE. RESULTS: Children and adolescents with respiratory allergic symptoms and sensitization had a higher serum IgA concentration at age 2 months than the non-atopic subjects. Colostrum and breast milk IgA concentrations were not associated with the development of allergic symptoms in the recipient infant. However, maternal milk IgA concentration at 6 months of lactation was inversely associated with elevated serum total IgE and positive skin prick test to tree pollen in the offspring at age 20 years. CONCLUSIONS AND CLINICAL RELEVANCE: Increased serum IgA concentration at age 2 months is associated with the development of subsequent allergic symptoms and sensitization in childhood and adolescence. Maternal milk IgA concentrations are not associated with subsequent allergic symptoms in the recipient infant. The present study provides novel information on the role of IgA in the development of respiratory allergy and sensitization.

High insulin levels are positively associated with peripheral nervous system function.

OBJECTIVE: The aim of this study was to analyze peripheral nervous system (PNS) function in overweight and obese individuals. MATERIALS AND METHODS: Forty-four adult non-diabetic overweight individuals were recruited. Peroneal motor nerve conduction and radial, sural, and medial plantar sensory nerve conduction were studied. Insulin and glucose levels were determined twice (over a 2- to 3-year period) with an oral glucose tolerance test (OGTT). Multiple stepwise linear regression models adjusted for age, height, weight, and skin temperature were used to analyze the data. RESULTS: Analysis revealed that baseline insulin levels measured 120 min after an OGTT explained 18% of the variation in peroneal F-wave minimum latency, 8% of peroneal F-wave maximum latency variation, 15% of sural sensory latency variation, 13% of sural sensory nerve conduction velocity (NCV) variation, and 10% of the variation in medial plantar sensory NCV. DISCUSSION AND CONCLUSION: Our study shows that serum insulin levels measured 120 min after an OGGT are positively associated with PNS function. High insulin levels without notably high glucose levels appear to be beneficial for the function of the PNS.

Serum cholesterol level in infancy is inversely associated with subsequent allergy in children and adolescents. A 20-year follow-up study.

BACKGROUND: Previous studies suggest an association between an altered lipoprotein profile and atopy. The association has been hypothesized to be due to alterations in the dietary fat intake, a factor possibly contributing to the increase of allergic diseases in industrialized countries. OBJECTIVE: We aimed at assessing whether there is an association between the serum lipid levels in infancy and subsequent development of allergic symptoms in childhood and adolescence. METHODS: A cohort of 200 unselected newborns was prospectively followed up from birth to age 20 years (from 1981 to 2002) with repeated measurements of total cholesterol from birth and throughout the first year of life. The subjects were re-examined at the ages of 5, 11 and 20 years, with assessment of the occurrence of allergic symptoms, skin prick testing (SPT) and measurement of total IgE and of the total, high- and low-density lipoprotein cholesterol. RESULTS: Children and adolescents with allergic symptoms, SPT positivity and an elevated IgE had lower total cholesterol levels in infancy and childhood than the non-atopic subjects. The difference was not detectable in cord blood, but became significant from age 2 months onward. CONCLUSION: The inverse association between the cholesterol level in infancy and subsequent manifestations of atopy seems not to be due to atopy-related dietary alterations, because it was already present in early infancy, when virtually all the infants were on a similar diet, i.e. on exclusive breastfeeding.

A handheld nerve conduction measuring device in carpal tunnel syndrome.

OBJECTIVES: The diagnostic utility and reliability of an easy-to-operate novel handheld nerve conduction tester in carpal tunnel syndrome (CTS) were evaluated. MATERIALS AND METHODS: Using the test device, the sensory nerve conductions (SNC) in the median and ulnar nerves were compared with each other in 194 patients with suspected CTS and 95 healthy controls. The test device results were compared with the results of nerve conduction studies (NCS) with traditional instrumentation. RESULTS: The new device correctly classified 145 of the 149 hands (97.3%) without median nerve lesion and 171 of the 200 hands (85.5%) with median nerve lesions in traditional NCS. The specificity of the new tester compared with traditional instrumentation was 98%. The correlation coefficient for different technicians in different studies was 0.87. CONCLUSIONS: The findings obtained with the new tester in CTS were reliable and reproducible. This tester may increase availability of NCS in CTS.

Retinol concentrations after birth are inversely associated with atopic manifestations in children and young adults.

BACKGROUND: Vitamin A has anti-inflammatory and immunomodulatory effects, and its deficiency results in impaired specific and innate immunity. Vitamin A is essential for inducing the gut-homing specificity on T cells. OBJECTIVE: As an impaired gut immune response in early infancy may contribute to the development of atopic sensitization, we looked for an association of plasma retinol concentrations and the subsequent development of allergic symptoms in healthy infants. METHODS: A cohort of 200 unselected, full-term newborns were followed up from birth to age 20 years. The plasma retinol concentration was determined in cord blood (n=97), at ages of 2, 4 and 12 months (n=95), and at ages 5 years (n=155) and 11 years (n=151). The subjects were re-examined at the ages of 5, 11 and 20 years with assessment of the occurrence of allergic symptoms during the preceding year, skin prick testing and measurement of serum total IgE. RESULTS: subjects with allergic symptoms or a positive skin prick test (SPT) in childhood or adolescence had lower retinol concentrations in infancy and childhood than symptom-free subjects. The difference was most pronounced at age 2 months. Retinol concentration at 2 months correlated inversely with positive SPT at ages of 5 and 20 years, and with allergic symptoms at age 20 years. CONCLUSION: Retinol concentration in young infants is inversely associated with the subsequent development of allergic symptoms. We propose that an inborn regulation of retinol may play a role in atopic sensitization, possibly through regulating the intestinal T cell responses.

Advanced leg salvage of the critically ischemic leg with major tissue loss by vascular and plastic surgeon teamwork: Long-term outcome.

OBJECTIVE: To assess long-term outcome and prognostic factors for extreme surgery by vascular and plastic surgical teamwork for leg salvage in patients with critically ischemic large tissue defects. SUMMARY BACKGROUND DATA: Combined vascular reconstruction and microvascular free-flap transfer has been used to improve distal perfusion and cover large tissue defects caused by the critical limb ischemia (CLI) in few dedicated centers during the past 15 years. Comorbidities compromise the results of these demanding operations, and it is unclear how far this mode of treatment should be extended. METHODS: During 1989 to 2003, altogether 2157 vascular or endovascular revascularizations for CLI manifested as tissue lesions were performed. These included 81 revascularizations combined with microvascular free flap transfers in 79 patients (37-85 years). All the patients were candidates for major amputation. The patients were followed up at least 2 years or to death (mean follow-up, 62 months; SD, +/-34 months). RESULTS: One- and 5-year leg salvage rates were 73% and 66%, survival rates 91% and 63%, and amputation-free survival rates of 70% and 41%, respectively. Male gender and American Society of Anesthesiologists score 4 were associated with an increased risk of death, whereas the involvement of the heel mostly with calcaneal osteomyelitis and a large size of defect predicted major amputation. CONCLUSIONS: A combined vascular reconstruction and free-flap transfer offers an option for advanced limb salvage in a selected group of patients with CLI and a major tissue defect. Poor general condition, the involvement of the heel, and a large defect would indicate an amputation over extreme attempts for limb salvage.

Prolonged exclusive breastfeeding is associated with increased atopic dermatitis: a prospective follow-up study of unselected healthy newborns from birth to age 20 years.

BACKGROUND: Exclusive breastfeeding for the first 6 months is recommended by the World Health Organization and considered allergy preventive. However, it is not known whether prolonging exclusive breastfeeding for over 6 months provides further benefit in allergy prevention. OBJECTIVE: The aim of this prospective 20-year follow-up study was to find out whether the allergy protective effect can be enhanced by prolonging strictly exclusive breastfeeding for > or =9 months of age. A total of 200 unselected healthy newborns were enrolled in the study. Their mothers were encouraged to maintain exclusive breastfeeding for as long as possible. The number of infants on strictly exclusive breastfeeding was 167 at 2, 116 at 6, 36 at 9 and 7 at 12 months of age. Of the 200 infants, 42% had a family history of allergy. The children were re-assessed at ages 5 (n=163), 11 (n=150) and 20 years (n=164) with clinical examination, skin prick testing, and parental and personal structured interviews. RESULTS: Exclusive breastfeeding prolonged for > or =9 months was associated with atopic dermatitis (P=0.002) and symptoms of food hypersensitivity (P=0.02) at age 5 years, and with symptoms of food hypersensitivity at age 11 years (P=0.01), in children with a family history of allergy. CONCLUSION: Prolonging strictly exclusive breastfeeding for > or =9 months was not helpful in atopy prevention, instead, it was associated with increased atopic dermatitis and food hypersensitivity symptoms in childhood.