Diversity and community structure of ectomycorrhizal fungi in a wooded meadow

Wooded meadows are seminatural plant communities that support high diversity of various taxa. Due to changes in land use, wooded meadows have severely declined during the last century. The dominant trees in wooded meadows acquire mineral nutrients via ectomycorrhizal fungi. Using anatomotyping and sequencing of root tips, interpolation and extrapolation methods, we studied the diversity and community structure of ectomycorrhizal fungi in two soil horizons of both managed and forested parts of a wooded meadow in Estonia. Species of Thelephoraceae, Sebacinaceae and the genus Inocybe dominated the whole ectomycorrhizal fungal community of 172 observed species. Forested and managed parts of the wooded meadow harboured different communities of ectomycorrhizal fungi, whereas soil horizon had a negligible effect on the fungal community composition. Diverse soil conditions and host trees likely support the high richness of ectomycorrhizal fungi in the wooded meadow ecosystem. Direct sequencing integrated with interpolation and extrapolation methods are promising to identify the fungi at the species level and to compare species richness between communities of ectomycorrhizal fungi.

Contrast sensitivity in 10 year old preterm and full term children: a population based study

AIMS

To determine the contrast sensitivity (CS) in 10 year old prematurely born children, previously included in a population based study on the incidence of retinopathy of prematurity (ROP), and in full term controls.

METHODS

This study included 205 prematurely born children and 215 children born at term, from the same geographical area and study period. CS was assessed monocularly with the Vistech 6500 test at five spatial frequencies (1.5-18 cycles/deg).

RESULTS

Prematurely born children had statistically significant lower CS at all frequencies, compared to full term ones. The mean differences in logarithmic CS were 0.03 (1.5 cycles/deg), 0.09 (3 cycles/deg), 0.10 (6 cycles/deg), 0.12 (12 cycles/deg), and 0.19 (18 cycles/deg). Even when the children with ROP and neurological disorders were excluded there was a difference between the two groups. Children who had been treated with cryotherapy had the lowest CS.

CONCLUSION

CS was lower in 10 year old prematurely born children than in full term ones of the same age. Whether this finding affects their visual function in daily life is uncertain.

A prospective, randomized clinical study on the effects of an amine fluoride/stannous fluoride toothpaste/mouthrinse on plaque, gingivitis and initial caries lesion development in orthodontic patients

The aim of this study was to examine the effect of combined use of a toothpaste/mouthrinse containing amine fluoride/stannous fluoride (AmF/SnF2; meridol) on the development of white spot lesions, plaque, and gingivitis on maxillary anterior teeth in orthodontic patients. A prospective, randomized, double-blind study with 115 orthodontic patients (42 males and 73 females, average age 14.4 years, drop outs 18) was designed. Group A (50) brushed twice daily with an AmF/SnF2 toothpaste (1400 ppm F) and rinsed every evening with an AmF/SnF2 solution (250 ppm F). Group B (47) brushed twice daily with a sodium fluoride (NaF) toothpaste (1400 ppm F) and rinsed every evening with a NaF solution (250 ppm F). Visible plaque index (VPI), gingival bleeding index (GBI) and white spot lesion index (WSL) were recorded on the six maxillary anterior teeth at bonding and after debonding, and evaluated with t tests. In group A no significant differences between bonding and debonding were recorded for WSL (1.02 +/- 0.08 versus 1.05 +/- 0.13, P = 0.14), VPI (0.10 +/- 0.21 versus 0.12 +/- 0.21, P = 0.66) or GBI (0.13 +/- 0.21 versus 0.16 +/- 0.22, P = 0.47), whereas statistically significant differences were found in group B between bonding and debonding for WSL (1.00 +/- 0.02 versus 1.08 +/- 0.17, P = 0.01), VPI (0.06 +/- 0.13 versus 0.17 +/- 0.25, P = 0.01) and GBI (0.06 +/- 0.12 versus 0.16 +/- 0.21, P = 0.01). The increase in lesions on the upper anterior teeth was 4.3 per cent in group A and 7.2 per cent in group B. It was concluded that the combined use of an AmF/SnF2 toothpaste/mouthrinse had a slightly more inhibitory effect on white spot lesion development, plaque and gingivitis on maxillary anterior teeth during fixed orthodontic treatment compared with NaF.

Graves' disease with moderate-severe endocrine ophthalmopathy-long term results of a prospective, randomized study of total or subtotal thyroid resection

The optimal thyroid surgery to be performed in patients with Graves' disease and concomitant endocrine ophthalmopathy is a matter of debate. We randomly assigned 44 patients with moderate-severe eye signs in a trial of treatment with subtotal, leaving a small (approximately 2 g) thyroid remnant, or total thyroidectomy. At inclusion, the patients had been treated with antithyroid drugs, and corticosteroids been given to 12 (27%). All received postoperative thyroxine supplementation and were followed for 3 years at regular examinations. The eye disease improved in all cases, and throughout the study, the two groups did not differ with regard to subjective and objective eye symptoms and laboratory findings. At the study start, motility disturbances were present in 8 and 11 of the cases in the subtotal and total resection group and proptosis in 16 and 17, respectively. After 3 years, the corresponding data were 3 and 6 cases with motility defects and 16 and 15 cases with proptosis. Thyrotropin (TSH)-receptor antibody levels gradually fell and became nondetectable in 21 (49%). The surgical complication rate (permanent recurrent laryngeal nerve paresis and permanent hypoparathyroidism) was significantly higher in the total thyroidectomy group. The data indicate that in patients with Graves' disease and active endocrine ophthalmopathy, subtotal thyroidectomy, leaving a small thyroid remnant, will reduce the risk of surgical complications but not the beneficial effect of surgery.

UNITE: a database providing web-based methods for the molecular identification of ectomycorrhizal fungi

Identification of ectomycorrhizal (ECM) fungi is often achieved through comparisons of ribosomal DNA internal transcribed spacer (ITS) sequences with accessioned sequences deposited in public databases. A major problem encountered is that annotation of the sequences in these databases is not always complete or trustworthy. In order to overcome this deficiency, we report on UNITE, an open-access database. UNITE comprises well annotated fungal ITS sequences from well defined herbarium specimens that include full herbarium reference identification data, collector/source and ecological data. At present UNITE contains 758 ITS sequences from 455 species and 67 genera of ECM fungi. UNITE can be searched by taxon name, via sequence similarity using blastn, and via phylogenetic sequence identification using galaxie. Following implementation, galaxie performs a phylogenetic analysis of the query sequence after alignment either to pre-existing generic alignments, or to matches retrieved from a blast search on the UNITE data. It should be noted that the current version of UNITE is dedicated to the reliable identification of ECM fungi. The UNITE database is accessible through the URL http://unite.zbi.ee

CNI-1493, an inhibitor of proinflammatory cytokines, retards cartilage destruction in rats with collagen induced arthritis

OBJECTIVE

To investigate if administration of CNI-1493, an inhibitor of the synthesis of proinflammatory cytokines and NO, protects against development of joint destruction in collagen induced arthritis (CIA) in rats.

METHODS

In a placebo controlled experiment, CNI-1493 was given once daily intraperitoneally after onset of clinical arthritis in DA rats. Disease progression was studied by clinical scoring of arthritis, serial measurement of serum levels of COMP, and histological examination of joints.

RESULTS

Clinical signs of arthritis were significantly reduced in the CNI-1493 treated group of rats in comparison with the placebo treated group. Histological examinations of paws demonstrated a significant reduction of cartilage destruction in the CNI-1493 treated group, but marked destruction of cartilage in the placebo group. Serum levels of COMP increased in the placebo group, whereas in the CNI-1493 treated group levels were low and decreased significantly during the observation time.

CONCLUSIONS

Treatment with CNI-1493 provides efficient protection against synovial inflammation and cartilage destruction when used therapeutically in CIA. The protective effect against cartilage destruction can be monitored by measuring serum COMP. These observations make CNI-1493 an attractive candidate for therapeutic studies in human arthritis, and COMP an attractive serum marker for monitoring joint protective effects.

High phylogenetic diversity among corticioid homobasidiomycetes

Homobasidiomycetes display a variety of fruit body morphologies. Examples include gilled mushrooms, coral fungi, polypores and puffballs but also species with simple crust-like basidiomata, usually called corticioid fungi. The latter group has largely been neglected in recent studies of homobasidiomycete evolution. The major goal of the present study was to explore the impact that the addition of a wide selection of species with crust-like basidiomata would have on homobasidiomycete phylogeny. Two genes, 5.8S and 28S in the nuclear rDNA repeats, were sequenced and a data set with 178 taxa analysed using neighbour-joining and maximum parsimony methods. Support for clades was evaluated by bootstrap. Basal nodes generally received weak support and branching order for major clades remained largely unresolved. Twelve major groups were recovered and corticioid fungi make up a major or important constituent in most of them. Nine groups are strongly supported but support for euagarics and polyporoid clades is poor. Phlebioid fungi were in earlier studies merged with the polyporoid clade but are here identified as a separate clade. Athelia is allied with ectomycorrhizal genera, inter alia Piloderma and Amphinema, in a separate clade forming a sister group to the boletes. We conclude that corticioid fungi hold a considerable share of the phylogenetic diversity displayed by homobasidiomycetes, and should always be considered when phylogenetic studies of larger basidiomycetes are designed.

Controversy over Hygrophorus cossus settled using ITS sequence data from 200 year-old type material

Sowerby described Agaricus cossus in 1799. The fungus possessed a smell, resembling that of a wounded larva of Cossus cossus (Lepidoptera). The species belongs in Hygrophorus, and since more than one white Hygrophorus species has this distinctive smell the epithet cossus has been variously interpreted. The complete internal transcribed spacer (ITS) region of the original type collection made in 1794, preserved in the Royal Botanic Gardens Kew herbarium, was successfully sequenced. Comparison with the ITS sequences from four other white aromatic-acidulous smelling Hygrophorus species, including the type specimen of H. quercetorum, showed that H. cossus is a species associated with Quercus and an older name for H. quercetorum. The differences in basidiome colouration developing with age and host-tree association appear to be the most useful characters to discriminate between the four species with a Cossus cossus smell. A table of morphological and ecological characters is provided.

Corticosteroid treatment of experimental arthritis retards cartilage destruction as determined by histology and serum COMP

OBJECTIVE

To examine if changes in serum cartilage oligomeric matrix protein (COMP) correlate with the development of cartilage damage, as measured by histological grading, in corticosteroid-treated animals with collagen-induced arthritis (CIA).

METHODS

DA rats with established CIA were treated with corticosteroids (betamethasone, 0.1 mg/kg body weight) or placebo (saline) intraperitoneally once daily after reaching an arthritis score exceeding 1. The treatment continued throughout the study. Arthritis progression was monitored by clinical scoring of paws, serial measurements of serum COMP and fibrinogen, and histological grading of paws.

RESULTS

Corticosteroid treatment reduced clinical signs of arthritis compared with placebo (arthritis score reduced, P < 0.01 at day 25). Corticosteroid treatment also reduced fibrinogen levels compared with placebo (P < 0.01). The morphological changes in the joint were less severe in the corticosteroid-treated animals (median cartilage score 4 in the placebo group, 0 in the corticosteroid-treated group; P < 0.01). The levels of COMP remained unchanged during treatment in the corticosteroid-treated arthritic animals, whereas an increase in levels of COMP was observed in rats treated with placebo (P < 0.01). There was a correlation between serum COMP and the extent of cartilage destruction at day 25 after immunization (r = 0.77, P < 0.001).

CONCLUSIONS

Corticosteroids given therapeutically to arthritic rats diminish joint destruction histologically, and stable serum COMP levels reflect this effect.

Hyaluronic acid accumulation; the mechanism behind graft rejection edema

Hyaluronic acid (HA) is an important stabilizing consistuent of the loose connective tissue and regulates water homeostasis. Thus, excessive accumulation of HA in interstitial tissue immobilizes water and may thereby contribute to interstitial tissue edema. By the use of biotin labelled core protein and an avidin-enzyme system, we visualized HA in grafted rat kidney, rat heart, rat small bowel and also in human kidneys. By an extraction procedure the tissue amounts of HA were measured in the experimental grafts. Simple techniques for measuring water content were also employed. The extracellular amounts of HA increased between 100% and 350% in rejecting tissues as compared to syngeneic controls. The relative water content also increased and correlated well with the HA accumulation. The clinical value of these experimental observations was confirmed in human transplantation where rejecting kidney allografts demonstrated a highly significant increase in HA staining in the interstitium as compared to non-rejecting biopsy specimens. We therefore concluded that transplantation edema--a key features of graft rejection--is regulated by the accumulation of HA not only under experimental conditions but also in the clinical setting.

Endoscopic treatment with dextranomer-hyaluronic acid for vesicoureteral reflux: histological findings

PURPOSE

Dextranomer-hyaluronic acid co-polymer is the first endoscopic bulking agent approved for vesicoureteral reflux in the United States. We evaluated the histopathological changes associated with this treatment in children with vesicoureteral reflux.

MATERIALS AND METHODS

Children 1 to 11 years old in whom treatment with dextranomer-hyaluronic acid co-polymer for grades III or greater vesicoureteral reflux had failed were eligible for the study. Failure was defined as persistent vesicoureteral reflux on voiding cystourethrography done approximately 3 months after implantation. At ureteral reimplantation the implant and surrounding ureteral tissue were resected and fixed for histopathological analysis. Tissue sections (4 to 5 microm.) were stained for routine histology and examined under a light microscope. Patients with a similar grade of vesicoureteral reflux who had not undergone endoscopic treatment served as the control group.

RESULTS

The study population comprised 23 patients with vesicoureteral reflux, of whom 13 with a mean age of 2 years 8 months at diagnosis underwent 1 to 3 treatments with dextranomer-hyaluronic acid co-polymer. The remaining 10 patients with a mean age of 1 year 10 months at diagnosis did not receive the bulking agent before ureteral reimplantation. The implant remained in situ 13 to 39 months (mean 22). On ureteral reimplantation the implant was located at the site of injection in 12 of the 13 patients. Histologically a granulomatous inflammatory reaction indicated by giant cell infiltration was observed at the implantation site. At ureteral reimplantation 9 implants were pseudo-encapsulated. Calcification was present in 9 ureters, while the eosinophil count was greater than 5 cells per 0.125 mm2 in 7 ureters treated with dextranomer-hyaluronic acid co-polymer. Mast cell infiltration was similar in the treatment and control groups.

CONCLUSIONS

Endoscopic treatment with dextranomer-hyaluronic acid co-polymer for vesicoureteral reflux is associated with a granulomatous reaction of the giant cell type, inflammatory cell infiltration and implant pseudo-encapsulation. They are typical histological findings associated with implantation of a foreign material. Dextranomer-hyaluronic acid co-polymer remains safe and effective for vesicoureteral reflux in children.

Screening for retinopathy of prematurity: evaluation and modification of guidelines

AIMS

To evaluate current screening guidelines for ROP (retinopathy of prematurity) and to determine whether they can be modified.

METHODS

In accordance with the authors' present criterion, infants born in Stockholm County, Sweden, from 1 August 1998 to 31 July 2000, with a gestational age of < or =32 weeks, were screened for ROP. The effectiveness of screening was studied.

RESULTS

The incidence of ROP was 25.5% in this study. A dropout group comprising almost 20% of the population studied (< or =32 weeks), was never referred, were lost to follow up, or died before screening was completed. No infant with a gestational age of >31 weeks at birth developed severe ROP (stages 3-5) and no infant with a gestational age of >29 weeks was treated for ROP.

CONCLUSION

80% of infants in this population with a gestational age at birth of < or =32 weeks, the current screening criterion, were effectively screened for ROP. The authors recommend that the screening criterion be lowered to Collapse

Key Words

• retinopathy of prematurity
• screening
• guidelines

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MESH Headings

• Birth Weight
• Female
• Gestational Age
• Humans
• Incidence
• Infant, Newborn
• Infant, Premature
• Logistic Models
• Male
• Practice Guidelines as Topic
• Predictive Value of Tests
• Prospective Studies
• Regression Analysis
• Retinopathy of Prematurity/diagnosis
• Retinopathy of Prematurity/epidemiology
• Sweden/epidemiology
• Vision Screening/methods

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Incidence of ROP in two consecutive Swedish population based studies

AIMS

To prospectively analyse the present incidence of ROP (retinopathy of prematurity) in a well defined geographical area in Sweden, and to compare it with that from a decade earlier in exactly the same area.

METHODS

Infants born between 1 August 1998 and 31 July 2000 with a birth weight of 1500 g or less were studied. They were screened for ROP from 5 weeks of postnatal age until the retina was entirely vascularised. The incidence of ROP, with its various stages, was compared with that of a previous (1988-90) population based study in the same geographical area.

RESULTS

The incidence of ROP in the present study was 36.4% (mild (18.2%) and severe ROP (18.2%)), which was similar to that of the previous study. Gestational age at birth remained the most important risk factor for ROP. We found a change in the distribution of ROP. The probability of ROP, particularly severe ROP, was highest in the most immature infants while it was lower in the least immature ones.

CONCLUSIONS

The incidence of ROP remained the same in two consecutive population based studies. The more "mature" infants developed ROP, particularly severe ROP, less often, while the most immature infants had ROP more often, particularly severe ROP.

Serum concentrations of cartilage oligomeric matrix protein, fibrinogen and hyaluronan distinguish inflammation and cartilage destruction in experimental arthritis in rats

OBJECTIVES

We investigated if changes in serum/plasma fibrinogen (FIB), hyaluronan (HA) and cartilage oligomeric matrix protein (COMP) levels can be used to differentiate between inflammation and cartilage involvement during arthritis.

METHODS

Collagen-induced arthritis (CIA), oil-induced arthritis (OIA) and for comparison, experimental autoimmune encephalitis (EAE) induced in DA rats were investigated.

RESULTS

Elevations of FIB concentrations were apparent at days 4-7 post-immunization in both arthritis models reaching a maximum on day 20-21, i.e. before peak arthritis. Elevations of HA in both models were seen shortly before macroscopically apparent arthritis, and peaked at or just before maximal arthritis, i.e. later in CIA than in OIA. COMP levels increased only after onset of arthritis and peaked late in disease (days 34-37), being significantly higher in the more destructive CIA compared with the less destructive OIA. During EAE flares, only FIB levels increased.

CONCLUSIONS

FIB is a general inflammation marker, HA appears to be a marker for synovitis and changes in COMP levels appear to reflect the cartilage destruction process.

One hundred and seventeen clades of euagarics

This study provides a first broad systematic treatment of the euagarics as they have recently emerged in phylogenetic systematics. The sample consists of 877 homobasidiomycete taxa and includes approximately one tenth (ca. 700 species) of the known number of species of gilled mushrooms that were traditionally classified in the order Agaricales. About 1000 nucleotide sequences at the 5(') end of the nuclear large ribosomal subunit gene (nLSU) were produced for each taxon. Phylogenetic analyses of nucleotide sequence data employed unequally weighted parsimony and bootstrap methods. Clades revealed by the analyses support the recognition of eight major groups of homobasidiomycetes that cut across traditional lines of classification, in agreement with other recent phylogenetic studies. Gilled fungi comprise the majority of species in the euagarics clade. However, the recognition of a monophyletic euagarics results in the exclusion from the clade of several groups of gilled fungi that have been traditionally classified in the Agaricales and necessitates the inclusion of several clavaroid, poroid, secotioid, gasteroid, and reduced forms that were traditionally classified in other basidiomycete orders. A total of 117 monophyletic groups (clades) of euagarics can be recognized on the basis on nLSU phylogeny. Though many clades correspond to traditional taxonomic groups, many do not. Newly discovered phylogenetic affinities include for instance relationships of the true puffballs (Lycoperdales) with Agaricaceae, of Panellus and the poroid fungi Dictyopanus and Favolaschia with Mycena, and of the reduced fungus Caripia with Gymnopus. Several clades are best supported by ecological, biochemical, or trophic habits rather than by morphological similarities.

Subacute bartonella infection in Swedish orienteers succumbing to sudden unexpected cardiac death or having malignant arrhythmias

During the period 1979-92, an increasing number of sudden unexpected cardiac deaths (SUCD) occurred in young, Swedish, male elite orienteers. Myocarditis was the most common diagnosis in the 16 victims, and in 4 cases was also associated with fatty infiltration mimicking arrhythmogenic right ventricular cardiomyopathy (ARVC). Tissues from autopsies of 5 orienteers were tested for Bartonella by PCR targeting the gltA (citrate-synthase) gene. The products were then sequenced. Antibodies to B. henselae, B. quintana and B. elizabethae were measured by indirect fluorescence antibody assay. Bartonella spp. DNA was detected in the hearts of 4 deceased orienteers, and in the lung of a fifth deceased case. The sequences were close to B. quintana in 2 cases and identical to B. henselae in 3. Four of these 5 cases, as well as 2 additional cases of elite orienteers with ARVC, indicated antibodies to Bartonella. It is suggested that Bartonella-induced silent subacute myocarditis, eventually leading to electric instability, caused the increased SUCD rate among the Swedish orienteers. It is further suggested that Bartonella infection may be a major pathogenetic factor in the development of ARVC-like disease. Although the mode of transmission is unknown, both zoonotic/vector-borne and parenteral person-to-person transmission may be involved.

Transversal dental arch dimensions in 9-year-old children born in the 1960s and the 1980s

The transversal arch dimension has been studied in 2 different cohorts of 9-year-old children, a group of 119 (56 girls and 63 boys) from Norway and a group of 133 (72 girls and 61 boys) from Sweden. Half of the children in each group were born in the 1960s and half in the 1980s. The maxillary and mandibular transversal dimensions did not differ between the 1960s groups and the 1980s groups when the maxilla and the mandible were studied separately. When the intermaxillary relationship was assessed, a significant reduction in the intermaxillary difference was found in the boys born in the 1980s compared with the boys born in the 1960s. This was confirmed with different measurement points. In the girls, the mesial drift of the first permanent molars, because of a greater prevalence of caries in the 1960s groups, masked this effect. When the mesial drift of the first permanent molars in the girls born in the 1960s was considered, the transversal intermaxillary difference showed the same secular pattern as in the boys. When the mesial drift of the first permanent molars was considered, the intermaxillary difference in the 1960s groups resembled that found in an American sample of northwest European ancestry born in the 1940s to a greater extent compared with the children born in the 1980s.

Stereological assessment of vulnerability of immunocytochemically identified striatal and hippocampal neurons after global cerebral ischemia in rats

Detailed quantitative analysis of the vulnerability of different hippocampal and striatal neurons to global forebrain ischemia has not previously been performed. Here we have studied the survival of immunocytochemically identified neurons using an unbiased stereological method in rats subjected to global forebrain ischemia for 30 min and sacrificed 48 h, 1 week or 4 weeks thereafter. Within the hippocampal formation, there was extensive, progressive loss of CA1 pyramidal neurons and dentate hilar neuropeptide Y (NPY)-positive interneurons. In contrast, no reduction of the number of CA3 and CA4 pyramidal neurons or hilar parvalbumin-positive interneurons was detected. In the dorsolateral striatum, the insult caused a major loss of projection neurons immunoreactive to dopamine- and adenosine 3':5'-monophosphate-regulated phosphoprotein with a molecular weight of 32 kilodalton (DARPP-32). The number of parvalbumin-positive striatal interneurons was significantly reduced, while NPY-positive interneurons were resistant. All striatal cholinergic interneurons survived the ischemic insult. At 48 h following the ischemia, the cholinergic interneurons within the lesioned striatum transiently expressed the p75 neurotrophin receptor (p75(NTR)), as shown by double-label immunocytochemistry. Furthermore, there was a significant increase in the number of choline acetyltransferase (ChAT)- and TrkA-immunoreactive interneurons at 4 weeks after the insult. Injections with the cell mitotic division marker BrdU provided no evidence that the elevated cholinergic cell number was due to neurogenesis. Probably, the higher number of ChAT- and TrkA-positive interneurons reflected increased intracellular levels of the corresponding proteins leading to more cells detectable with immunocytochemistry. This study gives the first quantitative description of the vulnerability of defined hippocampal and striatal neurons after global forebrain ischemia. The ischemia-induced increases of p75(NTR), TrkA and ChAT in cholinergic striatal interneurons at various time points after the insult suggest that neurotrophin signaling might be important for the survival and function of these cells in the post-ischemic phase.

Effects of combined application of antimicrobial and fluoride varnishes in orthodontic patients

A randomized prospective clinical study, with 220 patients scheduled for fixed orthodontic therapy, was conducted to test the hypothesis that application of an antimicrobial varnish in combination with a fluoride varnish (group 1) is significantly more efficient in reducing white spot lesions on the labial surfaces than application of the fluoride varnish alone (group 2). The effects of the antimicrobial varnish on the occurrence of gingivitis and plaque formation were also studied. A third aim was to investigate whether white spot lesion development could be predicted early during treatment. The antimicrobial varnish significantly reduced the number of mutans streptococci in plaque during the first 48 weeks of treatment. This effect did not result in significantly less development of white spot lesions on the labial surfaces compared with the group receiving only the fluoride varnish application. There was however a clear trend that the combination of the antimicrobial and fluoride varnishes more effectively reduced the increments of new lesions on the maxillary incisors. It was speculated that this could be due partly to an inhibiting effect of the antimicrobial varnish in an area with low oral clearance (with low pH and loss of fluoride) and partly to an inhibiting effect of the varnish on mutans streptococci. No significant differences between the groups with respect to gingivitis and plaque were found. Lesion development was difficult to predict early after bonding, despite a number of caries-relevant parameters of orthodontic importance. The best predictors for white spot lesions at debonding were visible plaque and mutans streptococci (eg, the level of oral hygiene and thus the cariogenic challenge) around the appliance shortly after bonding.