Harmonised statistics and maps of forest biomass and increment in Europe

Forest biomass is an essential resource in relation to the green transition and its assessment is key for the sustainable management of forest resources. Here, we present a forest biomass dataset for Europe based on the best available inventory and satellite data, with a higher level of harmonisation and spatial resolution than other existing data. This database provides statistics and maps of the forest area, biomass stock and their share available for wood supply in the year 2020, and statistics on gross and net volume increment in 2010-2020, for 38 European countries. The statistics of most countries are available at a sub-national scale and are derived from National Forest Inventory data, harmonised using common reference definitions and estimation methodology, and updated to a common year using a modelling approach. For those counties without harmonised statistics, data were derived from the State of Europe's Forest 2020 Report at the national scale. The maps are coherent with the statistics and depict the spatial distribution of the forest variables at 100 m resolution.

Quality of life: A way to buttress crisis program evaluations?

To test the applicability of the quality of life concept (QoL) in evaluations of financial assistance programs to sovereigns, we apply the OECD well-being framework to the programs in a euro area country, and find that the multidimensional framework promises policy-relevant findings, capable of informing other approaches for evaluating program relevance and effectiveness. The framework's headline indicators nevertheless, needed to be complemented with additional indicators owing to data challenges. The well-being dimensions demonstrate that our primary country case and other assisted euro area countries struggled to protect some vulnerable groups before and during the crisis years, although many QoL indicators depict improvement once program completion approached. In many cases, gender, age and education level related differences were apparent, and should be better considered in future crisis programs. The framework also facilitates considering governance elements with our enhancements. It offers good grounds for deepening the understanding of stakeholders' perception of reform benefits or shortcomings, thus of program ownership. By using the OECD framework we explore some interpretative limits of QoL in evaluation, and underscore that a full program evaluation would require careful integration in primary case data. Further research and data set improvements would enhance this approach's utility.

An Updated Global Species Diversity and Phylogeny in the Forest Pathogenic Genus Heterobasidion (Basidiomycota, Russulales)

Heterobasidion species are amongst the most intensively studied polypores because several species are aggressive white rot pathogens of managed coniferous forests mainly in Europe and North America. In the present study, both morphological and multilocus phylogenetic analyses were carried out on Heterobasidion samples from Asia, Oceania, Europe and North America. Three new taxa were found, i.e., H. armandii, H. subinsulare, and H. subparviporum are from Asia and are described as new species. H. ecrustosum is treated as a synonym of H. insulare. So far, six taxa in the H. annosum species complex are recognized. Heterobasidion abietinum, H. annosum, and H. parviporum occur in Europe, H. irregulare, and H. occidentale in North America, and H. subparviporum in East Asia. The North American H. irregulare was introduced to Italy during the Second World War. Species in the H. annosum complex are pathogens of coniferous trees, except H. subparviporum that seems to be a saprotroph. Ten species are found in the H. insulare species complex, all of them are saprotrophs. The pathogenic species are distributed in Europe and North America; the Asian countries should consider the European and North American species as entry plant quarantine fungi. Parallelly, European countries should consider the American H. occidentale and H. irregulare as entry plant quarantine fungi although the latter species is already in Italy, while North America should treat H. abietinum, H. annosum s.s., and H. parviporum as entry plant quarantine fungi. Eight Heterobasidion species found in the Himalayas suggest that the ancestral Heterobasidion species may have occurred in Asia.

Insights into the phylogeny of Northern Hemisphere Armillaria: Neighbor-net and Bayesian analyses of translation elongation factor 1-α gene sequences

Armillaria possesses several intriguing characteristics that have inspired wide interest in understanding phylogenetic relationships within and among species of this genus. Nuclear ribosomal DNA sequence-based analyses of Armillaria provide only limited information for phylogenetic studies among widely divergent taxa. More recent studies have shown that translation elongation factor 1-α (tef1) sequences are highly informative for phylogenetic analysis of Armillaria species within diverse global regions. This study used Neighbor-net and coalescence-based Bayesian analyses to examine phylogenetic relationships of newly determined and existing tef1 sequences derived from diverse Armillaria species from across the Northern Hemisphere, with Southern Hemisphere Armillaria species included for reference. Based on the Bayesian analysis of tef1 sequences, Armillaria species from the Northern Hemisphere are generally contained within the following four superclades, which are named according to the specific epithet of the most frequently cited species within the superclade: (i) Socialis/Tabescens (exannulate) superclade including Eurasian A. ectypa, North American A. socialis (A. tabescens), and Eurasian A. socialis (A. tabescens) clades; (ii) Mellea superclade including undescribed annulate North American Armillaria sp. (Mexico) and four separate clades of A. mellea (Europe and Iran, eastern Asia, and two groups from North America); (iii) Gallica superclade including Armillaria Nag E (Japan), multiple clades of A. gallica (Asia and Europe), A. calvescens (eastern North America), A. cepistipes (North America), A. altimontana (western USA), A. nabsnona (North America and Japan), and at least two A. gallica clades (North America); and (iv) Solidipes/Ostoyae superclade including two A. solidipes/ostoyae clades (North America), A. gemina (eastern USA), A. solidipes/ostoyae (Eurasia), A. cepistipes (Europe and Japan), A. sinapina (North America and Japan), and A. borealis (Eurasia) clade 2. Of note is that A. borealis (Eurasia) clade 1 appears basal to the Solidipes/Ostoyae and Gallica superclades. The Neighbor-net analysis showed similar phylogenetic relationships. This study further demonstrates the utility of tef1 for global phylogenetic studies of Armillaria species and provides critical insights into multiple taxonomic issues that warrant further study.

Viruses accumulate in aging infection centers of a fungal forest pathogen

Fungal viruses (mycoviruses) with RNA genomes are believed to lack extracellular infective particles. These viruses are transmitted laterally among fungal strains through mycelial anastomoses or vertically via their infected spores, but little is known regarding their prevalence and patterns of dispersal under natural conditions. Here, we examined, in detail, the spatial and temporal changes in a mycovirus community and its host fungus Heterobasidion parviporum, the most devastating fungal pathogen of conifers in the Boreal forest region. During the 7-year sampling period, viruses accumulated in clonal host individuals as a result of indigenous viruses spreading within and between clones as well as novel strains arriving via airborne spores. Viral community changes produced pockets of heterogeneity within large H. parviporum clones. The appearance of novel viral infections in aging clones indicated that transient cell-to-cell contacts between Heterobasidion strains are likely to occur more frequently than what was inferred from genotypic analyses. Intraspecific variation was low among the three partitivirus species at the study site, whereas the unassigned viral species HetRV6 was highly polymorphic. The accumulation of point mutations during persistent infections resulted in viral diversification, that is, the presence of nearly identical viral sequence variants within single clones. Our results also suggest that co-infections by distantly related viral species are more stable than those between conspecific strains, and mutual exclusion may play a role in determining mycoviral communities.

Cultural and climatic changes shape the evolutionary history of the Uralic languages

Quantitative phylogenetic methods have been used to study the evolutionary relationships and divergence times of biological species, and recently, these have also been applied to linguistic data to elucidate the evolutionary history of language families. In biology, the factors driving macroevolutionary processes are assumed to be either mainly biotic (the Red Queen model) or mainly abiotic (the Court Jester model) or a combination of both. The applicability of these models is assumed to depend on the temporal and spatial scale observed as biotic factors act on species divergence faster and in smaller spatial scale than the abiotic factors. Here, we used the Uralic language family to investigate whether both 'biotic' interactions (i.e. cultural interactions) and abiotic changes (i.e. climatic fluctuations) are also connected to language diversification. We estimated the times of divergence using Bayesian phylogenetics with a relaxed-clock method and related our results to climatic, historical and archaeological information. Our timing results paralleled the previous linguistic studies but suggested a later divergence of Finno-Ugric, Finnic and Saami languages. Some of the divergences co-occurred with climatic fluctuation and some with cultural interaction and migrations of populations. Thus, we suggest that both 'biotic' and abiotic factors contribute either directly or indirectly to the diversification of languages and that both models can be applied when studying language evolution.

A novel putative partitivirus of the saprotrophic fungus Heterobasidion ecrustosum infects pathogenic species of the Heterobasidion annosum complex

We characterized the bisegmented genome of a putative double-stranded (ds) RNA virus from a Chinese isolate of the fungus Heterobasidion ecrustosum, a member of the Heterobasidion insulare species complex. The larger genomic segment of 1885bp encoded a putative RNA dependent RNA polymerase (RdRp, 585aa), and the smaller one for a putative coat protein of 521aa (1826bp). Phylogenetic analyses suggest that this novel virus species, named as 'Heterobasidion RNA virus 3 from H. ecrustosum, strain 1' (HetRV3-ec1), can be assigned to the family Partitiviridae, being most similar to the Helicobasidium mompa dsRNA mycovirus with RdRp amino acid similarity of 54%. The similarity to known viruses of other Heterobasidion species was notably low (25-39%). The virus could be experimentally transmitted to members of the Heterobasidion annosum complex: the European Heterobasidion abietinum and North American Heterobasidion occidentale, and the original host strain could be cured from the virus by thermal treatment. Microscopical observations showed that hyphae of H. ecrustosum anastomosed occasionally with H. abietinum and H. occidentale, and suggested a possible route for horizontal transmission between these sexually incompatible species. The virus infection seemed to cause variable effects on the growth rate of its fungal hosts, but the results were strongly dependent on fungal strain, growth medium and incubation temperature.

Use of a breeding approach for improving biocontrol efficacy of Phlebiopsis gigantea strains against Heterobasidion infection of Norway spruce stumps

Sixty-four wild heterokaryotic isolates of Phlebiopsis gigantea were analysed for asexual spore production, growth rate and competitive ability against Heterobasidion in vitro, as well as growth rate in Norway spruce wood. These P. gigantea traits were considered important for controlling infection of Norway spruce stumps by spores of Heterobasidion spp. Ten most promising P. gigantea isolates were crossed with each other and 172 F(1) progeny heterokaryons were analysed for the above-mentioned traits. Thirteen most promising progeny heterokaryons were selected and their biocontrol ability against infection by Heterobasidion was compared with the parental isolates in stem pieces of Norway spruce. The results indicated that the progeny strains had generally better traits and control efficacy than the parental strains. The genetic effects accounted for a part of the variations between progeny and parental strains. This further suggests that there is a potential to improve the biocontrol properties of P. gigantea through breeding.

Apparent Diffusion Coefficient Histograms in the Follow-up of Relapsing-Remitting Multiple Sclerosis

Diffusion-weighted (DW) magnetic resonance (MR) imaging in addition to conventional magnetic resonance MR images provide valuable information in multiple sclerosis (MS). Increased diffusivity measured with diffusion-weighted imaging (DWI) has been demonstrated in normal appearing brain tissue in MS. So far, longitudinal changes taking place in whole-brain histograms in patients with active relapsing-remitting MS have not been evaluated. The aim of this study was to evaluate how apparent diffusion coefficient (ADC) histograms are altered during the follow-up of active relapsing-remitting MS patients. Nine patients were studied twice by MRI with a three-month interval. All patients had active newly diagnosed MS with two to three relapses during the year preceding the first MRI, and interferon-beta treatment was initiated after obtaining the first image. ADC histograms were produced after removing extracranial tissues and cerebrospinal fluid from the images. Additionally, brain volume index (BVI) and lesion volume on FLAIR images were measured. Five patients had signs of disease activity in the follow-up MRI. In the four patients without signs of disease activity the change in ADC histogram parameters was less than 2%. In patients with disease activity both increase (one case) and decrease (four cases) in histogram parameters were detected. Changes in BVI or lesion volume did not significantly correlate with histogram changes. The number of new T2-lesions showed a positive correlation with mean (r=0.79, P=0.014) and upper quartile (r=0.77, P=0.021) value change. Alterations in disease activity lead to histogram changes; both shifts to lower values and shifts to higher values are possible. The histogram changes are mostly related to subtle inflammatory changes in normal appearing brain tissue during inflammatory activity and their resolution during less active inflammatory conditions.

Effects of serum-free in vitro maturation of bovine oocytes on subsequent embryo development and cell allocation in two developmental stages of day 7 blastocysts

Maturation of oocytes and the subsequent outcome of the in vitro production (IVP) are affected by the composition of in vitro maturation (IVM) medium. To determine the use of serum interfering with effects of single molecules, we aimed at developing simplified IVM medium. The experimental IVM media were: (1) M199-medium supplemented with hormones and serum (control), (2) as 1 but serum was substituted with fatty acid-free serum albumin (FAFBSA) and (3) M199-medium without hormonal and serum supplementation (M199). The quality of embryos was assessed on day 7 by morphology and cryotolerance, as well as by Terminal deoxynucleotidyl Transferase Biotin-dUTP Nick End Labeling (TUNEL) and differential staining. Results showed that the nuclear maturation was suppressed in M199 group alone. Embryo cleavage and development rates, and the proportion of quality 1 blastocysts were lower in the FAFBSA and M199 groups compared to the control. Differences in the cell allocation of fresh embryos were observed at the blastocyst stage, but not at the expanded blastocyst stage. The control group blastocysts had larger number of cells allocated to the inner cell mass (ICM), and the FAFBSA group blastocysts larger apoptotic cell proportion compared to the blastocysts derived from other groups. After cryopreservation, the reduction of ICM proportion and increase of apoptotic cell proportion of embryos were equal between the experimental groups. In conclusion, exclusion of serum from the IVM media reduces embryo development and may cause perturbations in blastocyst development. Differences in the cell allocation of blastocysts between IVM media may appear only when the developmental stages are taken into account.

A study on intersterility groups of Armillaria in China

Mating tests were used to identify 282 basidiocarp specimens of Armillaria collected in 15 Chinese provinces, mostly in northern and southwestern parts of the country. Fourteen intersterile taxa were found, including the species A. borealis, A. gallica, A. mellea s.str., A. ostoyae, A. sinapina and A. tabescens and eight so far unnamed taxa called Chinese Biological Species (CBS) C, F, G, H, J, L, N and O. The CBS F might be A. singula, previously recorded from Japan, but six Chinese groups, C, H, J, L, N and O, are probably new biological species. The sexual system of 13 taxa is tetrapolar heterothallism. Homothallic forms also were found; they show a low degree of sexual compatibility with A. mellea s.str. and tentatively are included in the CBS G, but it is unclear whether this is a homogeneous group. Notes are presented on the distribution and ecology of the identified taxa.

Lung function and bronchial hyper-responsiveness 11 years after hospitalization for bronchiolitis

Aim: Atopic infants hospitalized for wheezing not caused by respiratory syncytial virus (RSV) carry the highest risk for later asthma. In the present paper, early risk factors for later lung function abnormalities and for bronchial hyper‐responsiveness (BHR) were evaluated in 81 children, hospitalized for bronchiolitis in infancy, at the median age of 12.3 years.

Methods: The basic data, including data on atopy in children and viral aetiology of bronchiolitis, had been collected on entry to the study at less than 2 years of age. Lung function was studied by flow‐volume spirometry (FVS), and BHR by methacholine and exercise challenge tests 11.4 years after hospitalization during infancy.

Results: RSV aetiology of bronchiolitis was associated with reduced forced vital capacity (FVC; 93.65% of predicted ± 11.05 vs. 99.57%± 12.59, p = 0.009). Early sensitization to inhalant allergens (OR 12.59, 95% CI 2.30–68.77) and maternal smoking during pregnancy (OR 4.58, 95% CI 1.28–16.39) were associated with BHR to exercise, and early atopic dermatitis (OR 3.48, 95% CI 1.09–11.10) was associated with BHR to methacholine.

Conclusions: RSV bronchiolitis was associated with a restrictive pattern of lung function. Early atopy and maternal smoking during pregnancy may play a role in the development and persistence of BHR.

297 A CASE REPORT: THE OUTCOME OF IVP MAY BE RELATED TO THE BATCH OF TCM-199 IN IVM

Chemicals used in bovine IVP may be inhibitory to embryo development (see, e.g., Van Soom A et al. 1994 Theriogenology 41, 325). The present study continued earlier experiments to optimize serum-free IVM protocol for bovine oocytes (Räty M. 2004 Reprod. Fert. Dev. 16, 281). The embryo development rate was much lower in the new experiments than in our previous studies. Thorough testing indicated that the batch of TCM-199 medium used in maturation was the reason for the lower embryo development results. In total, 14,589 abattoir-derived bovine oocytes in 23 batches were matured for 24 h in TCM-199 with glutamax-I (GIBCO, Paisley, UK), 0.25 mM Na-pyruvate, 100 IU mL−1 penicillin, 100 μg mL−1 streptomycin, 10 μg mL−1 LH, 2 μg mL−1 FSH, and 1 μg mL−1 β-estradiol supplemented as follows: (1) 10% FBS (GIBCO, New Zealand); (2) 4 mg mL−1 fatty acid-free albumin (FAFBSA) (Sigma-Aldrich, Helsinki, Finland); (3) 4 mg mL−1 polyvinylpyrrolidone (PVP) (Sigma) + growth factors (GF; 100 ng mL−1 IGF-I + 100 ng mL−1 EGF); or (4) as (3) but without FSH, LH, and β-estradiol (PVPGFwoH). Fertilized oocytes were denuded and cultured in modified SOFaaci + 4 mg mL−1 FAFBSA in 5% O2. (Holm P. et al. 1999 Theriogenology 52, 683–700). Two TCM-199 batches were used in separate IVM runs, batch 1 (Lot#3075638; 10 runs) and batch 2 (Lot#3081334; 13 runs). The statistical analyses were based on generalized linear mixed models. The estimated probabilities for embryo cleavage and development are shown in Table 1. The use of TCM-199 batch 1 resulted in significantly lower embryo development rates than the use of TCM-199 batch 2 in every IVM group studied. PVP IVM groups were the most sensitive for the TCM-199 batch and resulted in reduced embryo cleavage as well as strikingly low Day 7 embryo development. Our results indicate that TCM-199 batch 1 disturbed embryo development. In defined IVM groups (PVP groups), the maturation inhibiting role of TCM-199 batch 1 was seen already at the cleavage stage. It is possible that FBS and FAFBSA may have protected the oocytes to some extent against inhibitory effects of TCM-199. There is evidence for BSA acting as a chelating agent (see, e.g., Flood L.P. and Shirley B. 1991 Mol. Reprod. Dev. 30, 226–231). Table 1. Estimated probability for embryo cleavage at 38–42 hpi and Day 7 embryo development after IVM in two different batches of TCM-199

Thermophilic aeration of cattle slurry with whey and/or jam wastes

Thermophilic aeration of cattle slurry and food industrial by-products was studied with the aim to improve hygienic qualities of the slurry so that it could be used as a safe fertiliser for berries to be eaten raw. We also wanted to study if the process would be energetically favourable in an arctic climate. Cattle slurry alone or with whey and/or jam waste was treated. The tests were done in a well heat-insulated reactor with a 10 m(3) volume. Temperature increases up to over 70 degrees C could be recorded in 19 days even though some processes were carried out in winter time when the ambient air temperature was less than 0 degrees C. The heat energy formed was higher than the electrical energy needed to carry out the aeration. The hygienic qualities of the aerated product were good with only minor nitrogen losses. The end product could be useful as a fertiliser and soil improving compound to increase the organic matter content of agricultural soil. Cattle slurry alone was well suited as the raw material if attaining a high temperature was the main goal. A part of slurry could be replaced with food-industrial side products. Whey waste suited better for co-composting than jam waste but the mixture of whey, jam waste, and slurry was optimal for composting.

286 THE EFFECT OF IN VITRO MATURATION MEDIUM ON CRYOSURVIVAL, CELL NUMBERS AND APOPTOTIC INDEXES OF BOVINE EMBRYOS

The success of in vitro maturation (IVM) has a significant impact on the oocytes ability to develop to blastocyst stage. The quality of the produced blastocysts can be evaluated using staining techniques. The aims of this study were (a) to compare the effect of different IVM media on embryo production rates, and (b) to utilize differential (DF) and TUNEL staining to evaluate the quality and cryosurvival of the produced blastocysts. Abattoir-derived oocytes were randomly divided into the IVM groups: (1) M199 IVM (n = 2305): TCM-199 with glutamax-I (GIBCO, Paisley, UK), 0.25 mM Na-pyruvate, 100 IU mL−1 penicillin, and 100 μg mL−1 streptomycin; (2) FBS IVM (n = 2484): M199 IVM medium with hormones (10 μg mL−1 LH, 2 μg mL−1 FSH, and 100 μg mL−1 β-estradiol), and 10% FBS (GIBCO, New Zealand); and (3) FAFBSA IVM (n = 2411): as group (2), but FBS was replaced with 4 mg mL−1 fatty acid free albumin. Fertilized oocytes were denuded and cultured in modified SOFaaci + 4 mg mL−1 FAFBSA in 5% O2 (Holm P et al. 1999 Theriogenology 52, 683–700). Fresh, Grade I Day 7 blastocysts were stained with TUNEL (n = 114) or with DF (n = 149). In addition, 184 Grade I Day 7 blastocysts were frozen in AG Freeze (AB Technology, Pullman, WA, USA), thawed, and cultured for 24 h. The re-expanded embryos were stained with TUNEL (n = 96) or with DF (n = 88). Modified TUNEL protocol (Upstate, Lake Placid, NY, USA; Makarevich A and Markkula M 2002 Biol. Reprod. 66, 386–392) and DF staining protocol (Thouas G.A. et al. 2001 Reprod Biomed Online 3, 25–29) were used. The results of embryo cleavage and D7 embryo development are based on logistic regression models, and the results of proportion of ICM and apoptotic index on general linear mixed models. After FBS IVM, 83.6% of the fertilized oocytes were estimated to cleave and 25.5% to develop to the blastocyst stage by Day 7. The estimations for embryo cleavage and Day 7 development rates were significantly lower in FAFBSA IVM and M199 IVM groups (P < 0.0001): 74.0% and 15.0% for the FAFBSA, and 76.1% and 8.8% for the M199, respectively. The re-expansion rates (%) after thawing were 86.5, 90.6, and 73.3 for the FBS, FAFBSA, and M199 IVM groups, respectively. Freezing reduced the ICM proportions and elevated the apoptotic indexes (P < 0.001). The rate of ICM reduction after freezing was not influenced by the IVM medium. There was a significant interaction between the apoptotic index and the IVM group (P = 0.04). The increase of the apoptotic index was smallest in FAFBSA IVM and greatest in M199 IVM. The results indicate that exclusion of serum from IVM medium results in lower embryo cleavage and development rates. Freezing reduced ICM and increased apoptotic index of Day 7 embryos in every IVM group studied. FAFBSA IVM seemed to produce embryos of better quality as evidenced by the smallest increase in the apoptotic index after freezing.

Do inhaled steroids differ from cromones in terms of hospital admission rates for asthma in children?

AIM

The aim of the present study was to investigate the characteristics of hospital admissions in two child populations receiving different types of drugs as their regular medication for steady-state asthma.

METHODS

Annual data on children aged under 16 y treated for asthma, including consumption of regular medication for asthma, numbers of hospital periods, lengths of hospitalizations and annual proportions of readmissions, were collected using patient-specific medical records from 1995 to 1999. In the Kuopio province, on average, 35.6-36.7/1000 children were on maintenance for asthma, of which 23% were receiving cromones, 51% were taking inhaled steroids and 26% were treated with cromones plus intermittent steroids. In the Oulu province, the respective prevalence was 32.7-34.9/1000, and the respective proportions were 5%, 93% and 2%.

RESULTS

Total and first admissions, as well as hospital days were clearly less in the Oulu province. In the children aged > or = 6y, the average annual total admissions were 0.3/1000 (Oulu) vs 1.2/1000 (Kuopio) (p < 0.001). Similarly, the first admissions were 0.2/1000 vs 1.0/1000 (p < 0.001), proportions of readmissions 6.3% vs 19.3% (p < 0.05), and numbers of hospital days 0.7/1000 vs 3.8/1000 (p < 0.001). The differences were in the same direction, though less prominent, also among children 2-5 y of age.

CONCLUSION

Our results suggest that inhaled steroids are better than cromones in preventing admissions for asthma when two provinces with different practices for maintenance medication of steady-state asthma were compared.

Occupational exposure to chemical agents in the paper industry

As part of an International Agency for Research on Cancer (IARC) international epidemiological study of workers in the pulp and paper industry, previously unpublished exposure measurements were assembled in a database. This article summarizes the results of 3,873 measurements carried out in the production departments of paper and paperboard mills and recycling plants in 12 countries. In the paper and paperboard mills, most of the agents were measured in the pulping and refining departments and in on-machine coating and winding of paper/paperboard. Exposures to asbestos, carbon monoxide, formaldehyde, fungal spores, bacteria, nitrogen dioxide, minerals dusts, paper dust, sulphuric acid and different solvents sometimes exceeded exposure limit values. In the re-pulping and de-inking departments of recycling plants high exposures to formaldehyde, fungal spores, bacteria and paper dust were observed. High exposures to asbestos, bioaerosols, carbon monoxide and paper dust were found in many departments; ammonia, formaldehyde, mineral and paper dust and solvents were found in coating machines; and diphenyl and polychlorobiphenyls (PCBs) were found in some special circumstances. Measurements in the newsprint and uncoated paper machine departments revealed only a few elevated exposures. In nearly all departments, measurements of epichlorohydrin, PCBs, sulphur dioxide, hydrogen sulphide and mercaptans tended to be low, often even below their detection limits. In spite of some uncertainties in the measurement data, the study provides new insights into the level and variation of occupational exposures of production workers in the paper and paperboard industry.

Respiratory morbidity 20 years after RSV infection in infancy

Epidemiological data suggest that respiratory syncytial virus (RSV) infection in early life is a risk factor for later asthma. There are no prospective studies on RSV infection starting from infancy progressing through childhood into adulthood. We followed up a cohort of children, hospitalized for RSV bronchiolitis or RSV pneumonia before age 24 months, until age 18-20 years. The aim of the study was to evaluate early RSV infection as a risk factor for asthma, bronchial reactivity, and lung function abnormalities in young adults. The participants filled in a questionnaire on asthma and asthma-like symptoms. The clinical study included flow-volume spirometry (FVS), methacholine inhalation challenge (MIC), home PEF (peak expiratory flow) monitoring, and skin prick tests (SPT) to common allergens. Asthma was present in 17-22% of 36 index subjects, depending on asthma definition, compared to 11% of 45 controls. Furthermore, FEV% and MEF25 were lower, and MEF50 tended to be lower, in index than in control subjects. One or more abnormal lung function results were found in 16 (44%) index subjects, but only in 5 (11%) controls (P < 0.01). Bronchial reactivity (PD20 <4,900 microg methacholine) was demonstrated in 16 (46%) index subjects and 14 (32%) controls (NS). At least one positive SPT result was present in 21 (60%) index subjects; 6 (29%) had asthma (NS vs. nonatopic index subjects); 13 (62%) had abnormal lung function (P < 0.05); and 14 (67%) had bronchial reactivity (P < 0.01). In the logistic regression adjusted for atopy, as defined by SPT positivity, RSV infection in infancy was an independent risk factor for lung function abnormality (one or more abnormal results in FVS; OR, 5.27; 95% CI, 1.60-17.36), and also for decreased FEV% and MEF50 when these were analyzed separately. However, RSV infection in infancy was not a significant risk factor for asthma or bronchial reactivity. In young adults, lung function abnormalities may be associated with RSV infection which required hospitalization in infancy.

First Report of Heterobasidion parviporum (S Group of H. annosum sensu lato) on Tsuga spp. in Asia

Members of the Heterobasidion annosum (Fr.) Bref. complex are among the most important pathogens in coniferous forests of Europe and North America. Three intersterile groups (P, S, and F) have been found in this complex from Europe (1) and were recently segregated into three species based on intersterility, host preferences, and morphology (4). In a survey of wood-rotting fungi in China in 2002, Heterobasidion spp. were found on Tsuga chinensis (Franch.) Pritz and T. dumosa (D. Don) Eichl. in natural forests from the northern Sichuan Province of southwestern China (32°43' to 33°11' N, 103°50' to 103°53' E.). Basidiocarps of the fungus were relatively common on decayed wood in roots of dead trees, stumps, and fallen trunks. We collected four basidiocarps (Dai 4045, 4051, 4214, and 4224 in the Institute of Applied Ecology, Chinese Academy of Sciences, IFP) from three stands of mixed coniferous forests and made 40 homokaryotic, single-basidiospore cultures (02046, 02047, 02050, and 02051 in the Finnish Forest Research Institute). Two homokaryons from each basidiocarp were paired with homokaryotic tester strains of European H. annosum (P group), H. parviporum Niemelä & Korhonen (S group), and H. abietinum Niemelä & Korhonen (F group). The pairings showed that the progeny from the four basidiocarps are H. parviporum. The Chinese isolates did not form clamp connections with H. annosum sensu stricto, and a strong demarcation line developed in all these pairings. In contrast, the Chinese isolates formed clamp connections in almost every pairing with European H. parviporum, the clamp connections developed in both sides of the pairings, and no distinct demarcation line was present in most of these pairings. The Chinese homokaryons were also compatible with European H. abietinum, but in most of these pairings, clamp connections were found in the isolate from China but not in the European tester, and a demarcation line was present in most of the pairings. In contrast to H. annosum sensu stricto, the Chinese basidiocarps had smaller pores (4.5 to 6 per mm versus 3 to 4.5 per mm), and a thin tomentum on the pileal surface in contrast to the basidiocarps of H. abietinum. Previously, H. parviporum was found in Asia on coniferous hosts such as Abies, Larix, Picea and Pinus spp. (2). The North American S group of H. annosum sensu lato attacks species of Tsuga spp. in western North America (3), but to our knowledge, this is the first report of H. parviporum on native species of Tsuga spp. outside North America. References: (1) P. Capretti et al. Eur. J. For. Pathol. 20:231, 1990. (2) Y. C. Dai and K. Korhonen. Eur. J. For. Pathol. 29:273, 1999. (3) G. M. Filip and D. J. Morrison. North America. Pages 405-427 in: Heterobasidion annosum. Biology, Ecology, Impact and Control. CAB International, Wallingford, UK, 1998. (4) T. Niemelä and K. Korhonen. Taxonomy of the genus Heterobasidion. Pages 27-33 in: Heterobasidion annosum. Biology, Ecology, Impact and Control. CAB International, Wallingford, UK, 1998.

An unknown mechanism promotes somatic incompatibility in Ceratobasidium bicorne

Strains of Ceratobasidium bicorne (anamorph uninucleate Rhizoctonia), causing root dieback in nursery-grown conifer seedlings, were fruited in the laboratory and the pairing interactions among sibling, single-basidiospore progeny were investigated. No mating reactions were observed. Instead, a high frequency of somatic incompatibility was observed in progeny pairings, indicated by a killing reaction in hyphal anastomosis and by formation of a demarcation line. The F1 progeny also could be fruited, and the level of somatic incompatibility within the F2 progeny remained high, even if lower than in the F1 progeny. The interaction types in pairings within a family of progeny were similar in all respects to those between field isolates, indicating that the species is homothallic. The uninucleate condition of vegetative cells and the basidial characteristics would indicate homokaryotic fruiting, but the possibility of pseudohomothallism remains. We currently are not able to provide an explanation for the mechanism promoting somatic incompatibility in this species, but it seems likely that the classic heterogenic model of somatic incompatibility recognized in basidiomycetes is not applicable here. Alternative mechanisms are discussed.

Inpatient resource utilisation in younger (2-5 yrs) and older (6-14 yrs) asthmatic children in Finland

Asthma is the most common chronic disorder among Finnish children, however, the economic burden of paediatric asthma in Finland has not yet been comprehensively evaluated. The objective of this study was to compare inpatient resource utilisation between younger (2-5 yrs) and older children (6-14 yrs) with asthma in Finland. A national database of inpatient resource utilisation was applied to determine use of hospital services among children with asthma in 1999. Regional estimates of charges were combined with hospitalisation episodes to determine total inpatient cost. The results indicate that younger asthmatic children consume 3-times more inpatient resources per capita. Incidence of first admissions because of asthma was 3-times higher in younger children. Hospitalisation and rehospitalisation rates were also 3- and 4-times higher, respectively. The total annual inpatient cost of asthma in children aged 2-5 and 6-14 yrs was Euro 1.98 million with each group accounting for Euro 1.12 million and Euro 0.86 million, respectively. Regional and age-related differences in hospitalisation rates and costs were likely related to variable clinical practice on the primary level, difficulties with diagnosis and compliance among younger children.

Hospitalization trends for paediatric asthma in eastern Finland: a 10-yr survey

The prevalence of childhood asthma has increased during the past 20 yrs in eastern Finland. The use of regular medication for asthma has, consequently, also risen at the same time. The aim of the present study was to assess how these factors have influenced hospitalization for asthma in children. Data concerning the annual number of children aged <16 yrs treated for asthma, their number of hospital periods, and length of hospitalization were collected using patient-specific medical records for the years 1988-1997. Admissions for asthma more than doubled (from 1.2 in 1,000 to 2.7 in 1,000) (p<0.001), whereas re-admissions decreased from 28.1% to 8.7% (p<0.001) during the study period. The greatest increase was seen among children aged <2 yrs, whereas during recent years the admission rate among children aged >2 yrs has declined by one-third. Despite the increased prevalence of asthma, the decline in admissions seen in all but the youngest children may, at least partly, be attributed to the decrease in re-admissions, resulting from the early onset and increased use of inhaled steroids.

Assessment of exposure in an international study on cancer risks among pulp, paper, and paper product workers

A data management system and a department-exposure matrix (PAPDEM) was designed and constructed to facilitate exposure assessment for a large multinational study on cancer risks among pulp, paper, and paper product workers. Exposure to 25 major agents was described by prevalence, P (i.e., proportion of the exposed, classified %-range), and level, L (i.e., annual mean concentration at work, classified). Some agents could be assessed only in qualitative terms. The assessment was specific to mill, work department, agent, and time period. The results of industrial hygiene measurements, information from detailed company questionnaires, and the professional judgments of the assessment team were the cornerstones of the assessment. Validity and consistency of the assessment were aimed at by setting default values for P and L prior to the assessment, accurately defining agents and exposure classes, dividing assessment work by subindustry, working in pairs, testing interrater agreement, and finalizing the estimates in a meeting. In spite of these precautions, good agreement between different assessors was difficult to reach. Exposure to chemical agents turned out to be widespread and complex with frequent multiple exposures. A computer-assisted exposure assessment system such as PAPDEM may save time and facilitate assessment in large epidemiological studies requiring complicated exposure assessment procedures. It also provides a good documentation of exposure assignments, which may be useful in the interpretation of the results and in future updates of the study.

Reasons for and costs of hospitalization for pediatric asthma: a prospective 1-year follow-up in a population-based setting

The aims of this study were to examine the frequency of, and the reasons for, emergency hospitalization for asthma among children. In addition, the costs of hospital treatment, preventive medication, and productivity losses of the caregivers were evaluated in a population-based setting during 1 year. Data on purchases of regular asthma medication were obtained from the Social Insurance Institution. In total, 106 (2.3/1000) children aged up to 15 years were admitted 136 times for asthma exacerbation to the Kuopio University Hospital in 1998. This represented approximately 5% of all children with asthma in the area. The trigger for the exacerbation was respiratory infection in 63% of the episodes, allergen exposure in 24%, and unknown in 13%. The age-adjusted risk for admittance was 5.3% in children on inhaled steroids, 5.8% in those on cromones, and 7.9% in those with no regular medication for asthma. The mean direct cost for an admission was $1,209 (median $908; range $454-6,812) and the indirect cost was $358 ($316; $253-1,139). The cost of regular medication for asthma was, on average, $272 per admitted child on maintenance. The annual total cost as a result of asthma rose eight-fold if a child on regular medication was admitted for asthma.

Hyperbaric oxygen therapy in acute necrotizing infections. With a special reference to the effects on tissue gas tensions

Clostridial gas gangrene and perineal necrotizing fasciitis or Fournier's gangrene are rare but serious infections with an acute onset, rapid progression, systemic toxemia and a high mortality rate. The aim of this study was to investigate the efficacy of surgery, antibiotic treatment, surgical intensive care and in particular the role of hyperbaric oxygen (HBO) in the management of these infections. An experimental rat model was used to investigate the possibilities for measuring tissue oxygen and carbon dioxide tensions during hyperbaric oxygen treatment. In addition to this preliminary experimental study, Silastic tube tonometer and capillary sampling techniques were tested to measure the effect of hyperbaric oxygen treatment on subcutaneous oxygen and carbon dioxide tensions in patients with necrotizing fasciitis and healthy controls. Between January 1971 and April 1997, 53 patients with Clostridial gas gangrene were treated in the Department of Surgery, University of Turku. The patients underwent surgical debridement, broad spectrum antibiotic therapy and a series of hyperbaric oxygen treatments at 2.5 atmospheres absolute pressure (ATA). Twelve patients died (22.6%). Hyperbaric oxygen therapy in gas gangrene seems to be life-, limb- and tissue saving. Early diagnosis remains essential. Patient survival can be improved if the disease is recognized early and appropriate therapy instituted promptly. Between February 1971 and September 1996, 33 patients with perineal necrotizing fasciitis were treated in the Department of Surgery, University of Turku. The management included surgical debridement of the necrotic tissue with incisions and drainage of the involved areas, antibiotic therapy, hyperbaric oxygen treatment at 2.5 ATA pressure and surgical intensive care. Three patients died giving a mortality rate of 9.1%. The survivors received hyperbaric oxygen therapy for 2-12 times. Our results indicate that hyperbaric oxygenation is an important therapeutic adjunct in the treatment of Fournier's gangrene. Electrical equipment should not be used unsheltered in a hyperbaric chamber due to the increased risk of fire. The subcutaneous tissue gas tensions of rats were therefore measured using a subcutaneously implanted Silastic tube tonometer and a capillary sampling technique. The method was succesfully adapted to hyperbaric conditions. The subcutaneous oxygen tension levels increased five fold and the carbon dioxide tension levels two fold compared to intial levels. The PO2 and PCO2 of subcutaneous tissue and arterial blood were measured directly in six patients with necrotizing fasciitis and three healthy volunteers in normobaric conditions and during hyperbaric oxygen exposure at 2.5 ATA pressure. The measurements were carried out in healthy tissue and at the same time in the vicinity of the infected area of the patients. During HBO at 2.5 ATA subcutaneous oxygen tensions increased several fold from baseline values and carbon dioxide tensions also increased, but to a lesser degree in both healthy and infected tissues. When examining the subcutaneous PO2 levels measured from patients with necrotizing fasciitis, the PO2 was regularly higher in the vicinity of the infected area than in healthy tissue. In general, HBO treatment resulted in a marked increase in tissue oxygenation in both healthy tissue and in the vicinity of infected tissue. The hyperoxygenated tissue zone surrounding the infected area may be of significance in preventing the extension of invading microorganisms.

Diffusion and perfusion MR imaging in acute ischemic stroke: a comparison to SPECT

Diffusion (DWI) and perfusion (PWI) magnetic resonance imaging are relatively new methods of clinical imaging that probably can detect infarcted (DWI) and hypoperfused but still salvageable tissue (PWI) in acute human stroke. Forty-six acute stroke patients were imaged within 24 h of ictus, on the second day and after a week. SPECT was also performed on 23 patients in the acute phase (first or second day). On the first day, mean volume of hypoperfused tissue was significantly greater (P<0.001) than the infarcted tissue. The initial hypoperfusion volume correlated significantly with the final infarct size (P<0.001). The initial perfusion-diffusion mismatch correlated significantly with the infarct growth (P< or =0.001). The hypoperfusion volumes measured from PWI and SPECT correlated significantly (P<0.001). In conclusion, combined DWI and PWI is a powerful tool in evaluating the hemodynamics of acute ischemic stroke and can predict the infarct growth during 1 week.

Mechanical ventilation in children with severe asthma

Hospital admissions for childhood asthma have increased during the past few decades. The aim of this study was to describe the need for mechanical ventilation for severe asthma exacerbation in children in Finland from 1976 to 1995. We reviewed medical records and collected data retrospectively from all 5 university hospitals in Finland, thus covering the entire population of about 5 million. The endpoints selected were the number of admissions and readmissions leading to mechanical ventilation, duration of stay in the hospital, and mortality. Moreover, asthma medications prescribed prior to admission and administered in the intensive care unit (ICU), as well as the etiology of the exacerbation associated with mechanical ventilation were examined. Mechanical ventilation was required in 66 ICU admissions (59 patients). This constituted approximately 10% of all 632 admissions for acute asthma to an ICU. The number of admissions decreased from 1976 to 1995: 41 admissions between 1976 and 1985 vs. 25 admissions during the next 10-year period. The mean age at admission to the ICU was 3.6 years, and 46% of the patients were boys. Prior to the index admission, 70% of the patients had used asthma medication such as oral bronchodilator (50%), inhaled bronchodilator (20%), theophylline (38%), inhaled glucocorticoid (18%), oral glucocorticoid (5%), and cromoglycate (7%). Respiratory infection was by far the most common cause of all the exacerbations (61%), followed by food allergy (8%) and gastroesophageal reflux (3%). In 28% of cases the cause of the severe asthma exacerbation could not be identified. In the mechanically ventilated patients readmissions occurred 38 times between 1976 and 1985 vs. 5 times between 1986 and 1995. Five of the patients who received mechanical ventilation died, and in 3 of these patients asthma was the event causing death. In conclusion, there has been decrease in the number of first and repeat ICU admission for asthma requiring mechanical ventilation between 1970 and 1995. This trend occurred despite a simultaneous 5% yearly increase in hospital admissions for childhood asthma during these 2 decades.

Hyperbaric oxygen therapy in acute necrotizing infections with a special reference to the effects on tissue gas tensions

Clostridial gas gangrene and perineal necrotizing fasciitis or Fournier's gangrene are rare but serious infections with an acute onset, rapid progression, systemic toxemia and a high mortality rate. The aim of this study was to investigate the efficacy of surgery, antibiotic treatment, surgical intensive care and in particular the role of hyperbaric oxygen (HBO) in the management of these infections. An experimental rat model was used to investigate the possibilities for measuring tissue oxygen and carbon dioxide tensions during hyperbaric oxygen treatment. In addition to this preliminary experimental study, Silastic tube tonometer and capillary sampling techniques were tested to measure the effect of hyperbaric oxygen treatment on subcutaneous oxygen and carbon dioxide tensions in patients with necrotizing fasciitis and healthy controls. Between January 1971 and April 1997, 53 patients with Clostridial gas gangrene were treated in the Department of Surgery, University of Turku. The patients underwent surgical debridement, broad spectrum antibiotic therapy and a series of hyperbaric oxygen treatments at 2.5 atmospheres absolute pressure (ATA). Twelve patients died (22.6%). Hyperbaric oxygen therapy in gas gangrene seems to be life-, limb- and tissue saving. Early diagnosis remains essential. Patient survival can be improved if the disease is recognized early and appropriate therapy instituted promptly. Between February 1971 and September 1996, 33 patients with perineal necrotizing fasciitis were treated in the Department of Surgery, University of Turku. The management included surgical debridement of the necrotic tissue with incisions and drainage of the involved areas, antibiotic therapy, hyperbaric oxygen treatment at 2.5 ATA pressure and surgical intensive care. Three patients died giving a mortality rate of 9.1%. The survivors received hyperbaric oxygen therapy for 2-12 times. Our results indicate that hyperbaric oxygenation is an important therapeutic adjunct in the treatment of Fournier's gangrene. Electrical equipment should not be used unsheltered in a hyperbaric chamber due to the increased risk of fire. The subcutaneous tissue gas tensions of rats were therefore measured using a subcutaneously implanted Silastic tube tonometer and a capillary sampling technique. The method was successfully adapted to hyperbaric conditions. The subcutaneous oxygen tension levels increased five fold and the carbon dioxide tension levels two fold compared to initial levels. The PO2 and PCO2 of subcutaneous tissue and arterial blood were measured directly in six patients with necrotizing fasciitis and three healthy volunteers in normobaric conditions and during hyperbaric oxygen exposure at 2.5 ATA pressure. The measurements were carried out in healthy tissue and at the same time in the vicinity of the infected area of the patients. During HBO at 2.5 ATA subcutaneous oxygen tensions increased several fold from baseline values and carbon dioxide tensions also increased, but to a lesser degree in both healthy and infected tissues. When examining the subcutaneous PO2 levels measured from patients with necrotizing fasciitis, the PO2 was regularly higher in the vicinity of the infected area than in healthy tissue. In general, HBO treatment resulted in a marked increase in tissue oxygenation in both healthy tissue and in the vicinity of infected tissue. The hyper-oxygenated tissue zone surrounding the infected area may be of significance in preventing the extension of invading microorganisms.

Predictors of asthma three years after hospital admission for wheezing in infancy

OBJECTIVE

To evaluate the influence of early antiinflammatory therapy in the development of asthma 3 years after hospitalization for wheezing in infancy. In addition, the effects of allergic sensitization and respiratory syncytial virus (RSV) infection on the development of asthma were investigated.

DESIGN AND SETTING

A randomized, controlled follow-up study in a university hospital that provides primary hospital care for all pediatric patients in a defined area.

PATIENTS

Eighty-nine infants under 2 years of age who had been hospitalized for infection associated with wheezing and followed up for 3 years.

INTERVENTION

Early antiinflammatory therapy was given for 16 weeks; 29 patients received cromolyn sodium and 31 received budesonide. Twenty-nine control patients received no therapy.

OUTCOME MEASURES

Clinical diagnosis of current asthma, defined as having at least 3 episodes of physician-diagnosed wheezing and either a wheezing episode during the preceding year or ongoing antiinflammatory medication for asthma.

RESULTS

Fourteen (48%) patients in the former cromolyn group, 15 (48%) in the former budesonide group, and 16 (55%) in the control group had current asthma. The significant predictors of asthma were age over 12 months (risk ratio [RR] 4.1; 95% confidence interval [CI] = 1.59-10.35), history of wheezing (RR 6.8; CI = 1.35-34.43), and atopic dermatitis on study entry (RR 3.4; CI = 1.17-9.39). Skin prick test positivity at the age of 16 months significantly predicted asthma (RR 9.5; CI = 2.45-36.72). In addition, all of the 18 (20%) children sensitized with furred pet developed asthma. RSV identification (RR 0.3; CI = 0.08-0.80) and early furred pet contact at home (RR 0.3; CI 0.10-0.79) were associated with the decreased occurrence of asthma.

CONCLUSIONS

Antiinflammatory therapy for 4 months has no influence on the occurrence of asthma 3 years after wheezing in infancy. Early sensitization to indoor allergens, especially to pets, and atopic dermatitis predict subsequent development of asthma. RSV infection in wheezing infants may have a better outcome than other infections.

Acute childhood asthma in Finland: a retrospective review of hospital admissions from 1976 to 1995

The prevalence of childhood asthma has increased markedly in many Western societies during recent decades. We wanted to study whether the incidence and severity of childhood asthma in Finland had changed during the time-period 1976-95. Hospital admission rates from 1976 to 1995 were obtained from the National Hospital Discharge Register and the individual intensive care unit (ICU) registers of the five university hospitals in Finland. The number and length of treatment periods for childhood asthma in all Finnish hospitals and at the ICUs of the five university hospitals were analyzed. The number of children receiving special reimbursement for asthma medication costs was obtained from the central register of the Social Insurance Institution. The data showed that during the time-period investigated, hospital admissions as a result of asthma had increased by 2.8-fold, but the mean length of hospital stay had more than halved (from 7.3 to 2.6 days). The increase in hospital admissions showed greatest significance in the 0-4-year age-group among both sexes (p <0.001). In contrast, a significant reduction in hospital admissions was found among the 10-14-year age-group (p <0.001). No discernible change in admission to ICUs was seen. During the same time-period, the number of children receiving special reimbursement for asthma medication costs increased 7.5-fold. Hence, a major increase has occurred in the number of children diagnosed with asthma that has not been paralleled by a proportionate increase in the number of hospital admissions. While the prevalence of mild and moderate asthma has increased, the occurrence of severe asthma has remained essentially unchanged.

Pregnancy outcome in carriers of fragile X

OBJECTIVE

To evaluate pregnancy outcome in women who are carriers of fragile X.

DESIGN

Cross-sectional case-control study.

SETTING

Department of Obstetrics and Gynaecology, Kuopio University Hospital, Finland.

SAMPLE

Sixty-three singleton pregnancies in carriers of fragile X who were referred for genetic counselling and prenatal diagnosis to Kuopio University Hospital.

METHODS

Logistic regression analysis was used to compare pregnancy outcome in women who are fragile X carrier with outcome of the general obstetric population.

RESULTS

Carriers of fragile X often experienced more bleeding in late pregnancy than did the reference group. Otherwise, the course and outcome of pregnancy were comparable in both groups.

CONCLUSION

Pregnancy outcome in women who are carriers of fragile X is favourable. There is no need to initiate special fetal monitoring because of the fragile X status of the woman.

Genetic evidence for somatic haploidization in developing fruit bodies of Armillaria tabescens

Armillaria spp. have vegetative hyphae with diploid uninucleate cells, but the fruit bodies of many species contain clamped dikaryotic hyphae. Earlier observations suggest that somatic haploidization takes place in developing fruit bodies. To verify this, a uninucleate diploid cell was isolated from each of the 49 mating combinations between single-spore isolates of Armillaria tabescens and they were fruited. Twenty-four isolates produced fruit bodies with at least a partially dikaryotic subhymenium. Dikaryotic hyphae were isolated from fruit-body primordia and homokaryons were obtained by micromanipulation or by protoplasting. Approximately half of the isolates proved to represent recombinant mating types in respect to parent homokaryons, and most of them contained recombinant haploid DNA, based on random-amplified microsatellite markers. The results show that the nuclei in dikaryotic hyphae found in fruit bodies result from somatic haploidization. The mechanism of haploidization remains unclear.