Prevalence of anterior open bite in children and adolescents: a systematic review and meta-analysis.

PURPOSE: Anterior open bite is defined by the lack of incisal contact between the teeth in centric relation. The aim of this study was to determine the prevalence of anterior open in children and adolescents. METHODS: This systematic review included a search in the databases: PubMed, Scopus, Web of Science, LILACS, Google Scholar, and ProQuest. The acronym PECOS was considered: (P) children and adolescents, (E) presence of anterior open bite, (C) not applicable, (O) prevalence, and (S) observational studies. The risk of bias assessment was carried out using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data. The prevalence meta-analyses were performed using MedCalc® software. The certainty of the evidence was determined with the GRADE approach. RESULTS: 26 studies were included. Eleven studies were judged at low, seven at moderate, and eight at high risk of bias. The overall prevalence of anterior open bite was 16.52% (95% CI 12.34-21.17) in children and adolescents. The prevalence was 19.38% (95% CI 13.77-25.69) in South America. The prevalence of anterior open bite was 22.67% (95% CI 16.56-29.43) among females and 16.99% (95% CI 11.77-22.94) among males. The prevalence of anterior open bite was 18.84% (95% CI 13.88-24.38) in the primary dentition, and 14.26% (95% CI 7.67-22.46) in the mixed dentition. The overall certainty of the evidence was very low. CONCLUSION: The overall prevalence of anterior open bite was 16.52% in children and adolescents aged 2-16 years. Giving the limitations of a prevalence meta-analysis, the extrapolation of the results should be cautious. REGISTRATION NUMBER: CRD42020183162, 10 July 2020.

Successful treatment of babesiosis in a south-western black rhinoceros(Diceros bicornis bicornis).

Under stressful conditions, black rhinoceroses that are sub-clinical carriers of Babesia bicornis can succumb to babesiosis. After 16 days in captivity, a five-year-old female black rhino captured for relocation presented with inappetence, abdominal discomfort and constipation. After chemical immobilisation, dry faecal balls were removed from the rectum, peripheral blood smears were made and blood collected into EDTA tubes. She was treated prophylactically for colic with flunixin meglumine, penicillin and doramectin. Piroplasms were seen on fixed and stained peripheral blood smears. Overnight she developed severe haemoglobinuria, a sign consistent with babesiosis. Subsequently, DNA extracted from a blood specimen reacted with the B. bicornis probe on Reverse Line Blot (RLB) assay, confirming the diagnosis of babesiosis. Specific treatment consisted of 14 ml imidocarb dipropionate (dosage 2.4 mg/kg) administered intramuscularly by pole syringe. Fifteen days later the patient was still moderately anaemic, with the red blood cell (RBC) count, haematocrit and haemoglobin concentration within normal ranges but on microscopic examination there was a marked RBC macrocytosis and polychromasia indicative of a regenerative anaemia. DNA extracted from blood collected at that time did not react with the B. bicornis probe on RLB assay, indicating that treatment with imidocarb had been effective. Once the patient's appetite improved, she started gaining weight. After 82 days in captivity and 65 days after babesiosis had been diagnosed, she was released at the site where she had been captured.

Expansion of cytokine-producing CD4-CD8- T cells associated with abnormal Fas expression and hypereosinophilia.

The mechanisms of sustained overproduction of eosinophils in the idiopathic hypereosinophilic syndrome and in some human immunodeficiency virus (HIV)-1-infected individuals are largely unknown. We hypothesized that T cells may release soluble products that regulate eosinophilia in these patients, as has been previously shown in bronchial asthma. We identified one patient with idiopathic hypereosinophilic syndrome and one HIV-1-infected individual with associated hypereosinophilia who demonstrated high numbers of CD4-CD8- T cells in peripheral blood. CD4-CD8- T cells from both patients, although highly activated, did not express functional Fas receptors. In one case, the lack of functional Fas receptors was associated with failure of Fas mRNA and protein expression, and in another, expression of a soluble form of the Fas molecule that may have antagonized normal signaling of Fas ligand. In contrast to the recently described lymphoproliferative/autoimmune syndrome, which is characterized by accumulation of CD4-CD8- T cells and mutations within the Fas gene, this study suggests somatic variations in Fas expression and function quite late in life. Both genetic and somatic abnormalities in regulation of the Fas gene are therefore associated with failures to undergo T cell apoptosis. Furthermore, the expanded population of CD4-CD8- T cells from both patients elaborated cytokines with antiapoptotic properties for eosinophils, indicating a major role of these T cells in the development of eosinophilia. Thus, this study demonstrates a sequential dysregulation of apoptosis in different cell types.

Transition from Connected to Fragmented Vegetation across an Environmental Gradient: Scaling Laws in Ecotone Geometry.

A change in the environmental conditions across space-for example, altitude or latitude-can cause significant changes in the density of a vegetation type and, consequently, in spatial connectivity. We use spatially explicit simulations to study the transition from connected to fragmented vegetation. A static (gradient percolation) model is compared to dynamic (gradient contact process) models. Connectivity is characterized from the perspective of various species that use this vegetation type for habitat and differ in dispersal or migration range, that is, "step length" across the landscape. The boundary of connected vegetation delineated by a particular step length is termed the " hull edge." We found that for every step length and for every gradient, the hull edge is a fractal with dimension 7/4. The result is the same for different spatial models, suggesting that there are universal laws in ecotone geometry. To demonstrate that the model is applicable to real data, a hull edge of fractal dimension 7/4 is shown on a satellite image of a piñon-juniper woodland on a hillside. We propose to use the hull edge to define the boundary of a vegetation type unambiguously. This offers a new tool for detecting a shift of the boundary due to a climate change.

A multicentre phase II trial of gemcitabine for the treatment of patients with newly diagnosed, relapsed or chemotherapy resistant mantle cell lymphoma: SAKK 36/03.

Mantle cell lymphoma (MCL) has a poor prognosis with often short and incomplete remissions. We aimed to test the efficacy and tolerability of gemcitabine in treating MCL. Gemcitabine was given in doses of 1000 mg/m(2) as a 30 min infusion on days 1 and 8 of each 3 week cycle for a maximum of nine cycles. Eighteen patients with a median age of 70 years were recruited. MCL was newly diagnosed in half of patients and relapsed in the remainder. Fifteen patients had Ann Arbor stage IV. The best-recorded responses were 1 CR (complete remission), 4 PRs (partial responses), 8 SDs (stable diseases) and 4 PDs (diseases progression). The response rate (RR) (CR + PR) was 5 (28%; 95% confidence interval: 7.1, 48.5). The patient achieving a CR had stage IV disease. Most haematological adverse events occurred during the first chemotherapy cycle. Three patients developed non-haematological serious adverse events: dyspnea, glomerular microangiopathy with haemolytic uremic syndrome (HUS) and hyperglycaemia. The median time-to-progression and treatment response duration (TRD) was 8.0 (95% confidence interval: 5.5, 9.3) and 10.6 (95% confidence interval: 5.5, 10.9) months, respectively. We conclude that Gemcitabine is well tolerated, moderately active and can induce disease stabilization in patients with MCL.

Versican is expressed in the proliferating zone in the epidermis and in association with the elastic network of the dermis.

The expression of the large chondroitin sulfate proteoglycan versican was studied in human adult skin. For this purpose, bacterial fusion proteins containing unique portions of the versican core protein were prepared. Polyclonal antibodies against the fusion proteins specifically reacted with versican from a proteoglycan fraction of MG63 osteosarcoma cells. In immunohistochemical experiments, the affinity-purified antibodies localized versican in the stratum basale of the epidermis, as well as in the papillary and reticular layers of the dermis. An apparent codistribution of versican with the various fiber forms of the elastic network of the dermis suggested an association of versican with microfibrils. Both dermal fibroblasts and keratinocytes expressed versican in culture during active cell proliferation. In line with the observation that versican is absent in the suprabasal layers of the epidermis where keratinocytes terminally differentiate, culture conditions promoting keratinocyte differentiation induced a down-regulation of versican synthesis. In Northern blots versican mRNA could be detected in extracts from proliferating keratinocytes and dermal fibroblasts. Comparison of RNA preparations from semi-confluent and confluent fibroblast cultures demonstrated decreasing amounts of versican mRNA at higher cell densities. This inverse correlation of versican expression and cell density was confirmed by indirect immunofluorescence staining of cultured fibroblasts and keratinocytes. The localization of versican in the basal zone of the epidermis as well as the density dependence of versican in cell cultures suggest a general function of versican in cell proliferation processes that may not solely be confined to the skin.

Immunohistochemical and mutation analyses demonstrate that procollagen VII is processed to collagen VII through removal of the NC-2 domain.

Collagen VII is the major structural constituent of anchoring fibrils in the skin. It is synthesized as a procollagen that is larger than the collagen deposited in the tissue. In this study, we investigated the conversion of procollagen VII to collagen VII in human skin and in cutaneous cells in vitro and identified the propeptide using domain-specific antibodies. For this purpose, two bacterial fusion proteins containing unique sequences of the carboxy-terminal globular NC-2 domain of procollagen VII were prepared, and polyclonal antibodies raised against them. Immunoblotting showed that the anti-NC2 antibodies reacted with procollagen VII isolated from cultured keratinocytes, but not with collagen VII extracted from the skin. Immunohistochemical experiments with the NC-2 antibodies revealed a strong reaction in cultured keratinocytes, but the basement membrane zone of normal skin remained negative. The staining could not be rendered positive by chemical or enzymatic unmasking of potential hidden epitopes in the skin, indicating that most of the NC-2 domain is absent from normal skin. In contrast, a positive staining with NC-2 antibodies was observed in the skin of a patient with NC-2 antibodies was observed in the skin of a patient with dystrophic epidermolysis bullosa, who carried a 14-bp deletion at one of the intro-exon junctions of the collagen VII gene. This aberration led to an in-frame skipping of exon 115 from the mRNA and eliminated 29 amino acids from the NC-2 domain which include the putative cleavage site for the physiological processing enzyme, procollagen C-proteinase. The results indicate that in normal human skin, the removal of the NC-2 domain from procollagen VII precedes its deposition at the dermal-epidermal junction. Furthermore, they suggest that an aberration in the procollagen VII cleavage interferes with the normal fibrillogenesis of the anchoring fibrils.

Molecular evidence for chlamydial infections in the eyes of sheep.

Ocular infections by chlamydiae are associated with ocular disease manifestations such as conjunctivitis and keratitis in humans and animals. Limited evidence exists that members of the order Chlamydiales can also cause ocular disease in sheep. In the current study, the prevalence of chlamydiae in the eyes of sheep was investigated by using PCR methods. Data obtained in sheep by broad-range 16S rRNA order Chlamydiales-specific PCR were compared to the prevalence of antibodies against chlamydiae detected by a competitive enzyme-linked immunosorbent assay (cELISA). Flocks tested included a clinically healthy flock and two flocks suffering from ocular disease and with histories of Ovine Enzootic Abortion (OEA). PCR detected DNA of Chlamydophila (Cp.) abortus and Cp. pecorum in the eyes of both healthy and sick animals but also identified Chlamydia (C.) suis and a variety of uncultured chlamydia-like organisms. Good correlation was found between the presence of Cp. abortus DNA in sheep conjunctival samples and seropositivity detected by cELISA. Despite these findings, no association was found between the presence of chlamydial DNA in the sheep conjunctival samples and the onset of clinical disease. These results suggest that the biodiversity of chlamydiae in the eyes of sheep is greater than that previously thought. Further investigations are needed to determine whether a causal relationship between infection by chlamydiae and ocular disease exists in these animals.

A non-invasive probe for online-monitoring of turgor pressure changes under field conditions.

An advanced non-invasive, field-suitable and inexpensive leaf patch clamp pressure probe for online-monitoring of the water relations of intact leaves is described. The probe measures the attenuated output patch clamp pressure, P(p), of a clamped leaf in response to an externally applied input pressure, P(clamp). P(clamp) is generated magnetically. P(p) is sensed by a pressure sensor integrated into the magnetic clamp. The magnitude of P(p) depends on the transfer function, T(f), of the leaf cells. T(f) consists of a turgor pressure-independent (related to the compression of the cuticle, cell walls and other structural elements) and a turgor pressure-dependent term. T(f) is dimensionless and assumes values between 0 and 1. Theory shows that T(f) is a power function of cell turgor pressure P(c). Concomitant P(p) and P(c) measurements on grapevines confirmed the relationship between T(f) and P(c). P(p) peaked if P(c) approached zero and assumed low values if P(c) reached maximum values. The novel probe was successfully tested on leaves of irrigated and non-irrigated grapevines under field conditions. Data show that slight changes in the microclimate and/or water supply (by irrigation or rain) are reflected very sensitively in P(p).

Evidence for discontinuous water columns in the xylem conduit of tall birch trees.

The continuity of the xylem water columns was studied on 17- to 23-m tall birch trees (trunk diameter about 23 cm; first branching above 10 m) all year round. Fifty-one trees were felled, and 5-cm thick slices or 2-m long boles were taken at regular, relatively short intervals over the entire height of the trees. The filling status of the vessels was determined by (i) xylem sap extraction from trunk and branch pieces (using the gas bubble-based jet-discharge method and centrifugation) and from trunk boles (using gravity discharge); (ii) (1)H nuclear magnetic resonance imaging of slice pieces; (iii) infusion experiments (dye, (86)Rb(+), D(2)O) on intact trees and cut branches; and (iv) xylem pressure measurements. This broad array of techniques disclosed no evidence for continuous water-filled columns, as postulated by the Cohesion-Tension theory, for root to apex directed mass transport. Except in early spring (during the xylem refilling phase) and after extremely heavy rainfall during the vegetation period, cohesive/mobile water was found predominantly at intermediate heights of the trunks but not at the base or towards the top of the tree. Similar results were obtained for branches. Furthermore, upper branches generally contained more cohesive/mobile water than lower branches. The results suggest that water lifting occurs by short-distance (capillary, osmotic and/or transpiration-bound) tension gradients as well as by mobilisation of water in the parenchymatic tissues and the heartwood, and by moisture uptake through lenticels.

Effects on capacitance by overexpression of membrane proteins.

Functional Channelrhodopsin-2 (ChR2) overexpression of about 10(4)channels/mum(2) in the plasma membrane of HEK293 cells was studied by patch-clamp and freeze-fracture electron microscopy. Simultaneous electrorotation measurements revealed that ChR2 expression was accompanied by a marked increase of the area-specific membrane capacitance (C(m)). The C(m) increase apparently resulted partly from an enlargement of the size and/or number of microvilli. This is suggested by a relatively large C(m) of 1.15+/-0.08 microF/cm(2) in ChR2-expressing cells measured under isotonic conditions. This value was much higher than that of the control HEK293 cells (0.79+/-0.02 microF/cm(2)). However, even after complete loss of microvilli under strong hypoosmolar conditions (100 mOsm), the ChR2-expressing cells still exhibited a significantly larger C(m) (0.85+/-0.07 microF/cm(2)) as compared to non-expressing control cells (0.70+/-0.03 microF/cm(2)). Therefore, a second mechanism of capacitance increase may involve changes in the membrane permittivity and/or thickness due to the embedded ChR2 proteins.

A novel, non-invasive, online-monitoring, versatile and easy plant-based probe for measuring leaf water status.

A high-precision pressure probe is described which allows non-invasive online-monitoring of the water relations of intact leaves. Real-time recording of the leaf water status occurred by data transfer to an Internet server. The leaf patch clamp pressure probe measures the attenuated pressure, P(p), of a leaf patch in response to a constant clamp pressure, P(clamp). P(p) is sensed by a miniaturized silicone pressure sensor integrated into the device. The magnitude of P(p) is dictated by the transfer function of the leaf, T(f), which is a function of leaf patch volume and ultimately of cell turgor pressure, P(c), as shown theoretically. The power function T(f)=f(P(c)) theoretically derived was experimentally confirmed by concomitant P(p) and P(c) measurements on intact leaflets of the liana Tetrastigma voinierianum under greenhouse conditions. Simultaneous P(p) recordings on leaflets up to 10 m height above ground demonstrated that changes in T(f) induced by P(c) changes due to changes of microclimate and/or of the irrigation regime were sensitively reflected in corresponding changes of P(p). Analysis of the data show that transpirational water loss during the morning hours was associated with a transient rise in turgor pressure gradients within the leaflets. Subsequent recovery of turgescence during the afternoon was much faster than the preceding transpiration-induced water loss if the plants were well irrigated. Our data show the enormous potential of the leaf patch clamp pressure probe for leaf water studies including unravelling of the hydraulic communication between neighbouring leaves and over long distances within tall plants (trees).

Exploration of the APC/beta-catenin (WNT) pathway and a histologic classification system for pulmonary artery intimal sarcoma. A study of 18 cases.

APC, a tumor suppressor gene in the Wnt pathway, stabilizes beta-catenin and controls cell growth. Mutation of APC or beta-catenin leads to nuclear accumulation of beta-catenin and transcription of cyclin D1/cyclin A. Pulmonary artery sarcoma (PAS) were studied by morphologic, immunohistochemical, and molecular genetic methods of the Wnt pathway. Eighteen cases were included: mean age 52 years, primary intraluminal location with typical clinical presentation. PAS were classified as epithelioid (n = 4) or malignant fibrous histiocytoma (MFH; spindled/pleomorphic, n = 4), myxofibrosarcoma (n = 8), and one each hemangiopericytoma-like or malignant inflammatory myofibroblastic tumor-like. The tumor cells demonstrated vimentin, focal actins, and rare focal desmin positivity. All but one were grade 2 or 3 by FNCLCC grading. Alteration in chromosome 5q21 (APC) was found in 4/14 PAS by LOH, mostly epithelioid-type; an MFH-type case demonstrated microsatellite instability (MSI) and nuclear beta-catenin. Cyclin D1 was expressed in seven tumors, all myxofibrosarcoma-type. No mutations were detected in APC or beta-catenin. In summary, PAS are predominantly intermediate grade myxofibrosarcoma in middle-aged males, and fatal in two-thirds of patients. Despite myofibroblastic phenotype, APC/beta-catenin pathway changes are rare. Cyclin D1, only expressed in the myxofibrosarcoma-type, is likely transcribed via factors other than beta-catenin.

The mechanisms of refilling of xylem conduits and bleeding of tall birch during spring.

Seasonal variations in osmolality and components of xylem sap in tall birch trees were determined using several techniques. Xylem sap was extracted from branch and trunk sections of 58 trees using the very rapid gas bubble-based jet-discharge method. The 5-cm long wood pieces were taken at short intervals over the entire tree height. The data show that large biphasic osmolality gradients temporarily exist within the conducting xylem conduits during leaf emergence (up to 272 mosmol x kg(-1) at the apex). These gradients (arising mainly from glucose and fructose) were clearly held within the xylem conduit as demonstrated by (1)H NMR imaging of intact twigs. Refilling experiments with benzene, sucrose infusion, electron and light microscopy, as well as (1)H NMR chemical shift microimaging provided evidence that the xylem of birch represents a compartment confined by solute-reflecting barriers (radial: lipid linings/lipid bodies; axial: presumably air-filled spaces). These features allow transformation of osmolality gradients into osmotic pressure gradients. Refilling of the xylem occurs by a dual mechanism: from the base (by root pressure) and from the top (by hydrostatic pressure generated by xylem-bound osmotic pressure). The generation of osmotic pressure gradients was accompanied by bleeding. Bleeding could be observed at a height of up to 21 m. Bleeding rates measured at a given height decreased exponentially with time. Evidence is presented that the driving force for bleeding is the weight of the static water columns above the bleeding point. The pressure exerted by the water columns and the bleeding volume depend on the water-filling status of (communicating) vessels.

A fully automated correction method of EOG artifacts in EEG recordings.

OBJECTIVE: A fully automated method for reducing EOG artifacts is presented and validated. METHODS: The correction method is based on regression analysis and was applied to 18 recordings with 22 channels and approx. 6 min each. Two independent experts scored the original and corrected EEG in a blinded evaluation. RESULTS: The expert scorers identified in 5.9% of the raw data some EOG artifacts; 4.7% were corrected. After applying the EOG correction, the expert scorers identified in another 1.9% of the data some EOG artifacts, which were not recognized in the uncorrected data. CONCLUSIONS: The advantage of a fully automated reduction of EOG artifacts justifies the small additional effort of the proposed method and is a viable option for reducing EOG artifacts. The method has been implemented for offline and online analysis and is available through BioSig, an open source software library for biomedical signal processing. SIGNIFICANCE: Visual identification and rejection of EOG-contaminated EEG segments can miss many EOG artifacts, and is therefore not sufficient for removing EOG artifacts. The proposed method was able to reduce EOG artifacts by 80%.

Prevalence of chlamydiae in semen and genital tracts of bulls, rams and bucks.

Chlamydiae infect male genital organs of ruminants. However, little is known about their prevalence. Hence, we investigated fresh and cryopreserved semen (bulls: n=304; rams: n=78; bucks: n=44) by polymerase chain reaction (PCR), as well as genital organs (bulls: n=13; rams: n=10; bucks: n=6) by immunohistochemistry (IHC) and PCR. Sera from bulls (n=104) and small ruminants (n=61) were tested by LPS and rMOMP (recombinant major outer membrane protein) ELISA and competitive ELISA (cELISA), respectively. Three PCR assays were compared in this study for detection of chlamydial DNA in semen: 16S rRNA, IGS-S (intergenic spacer 16S/23S-short), and IGS-L (intergenic spacer 16S/23S-long) PCRs. PCR sensitivity and inhibitory effects were determined by spiking semen with Chlamydophila (Cp.) abortus DNA. In bull semen, detection limits of the 16S, IGS-S and IGS-L PCRs were 10, 10, 100 templates, respectively. However, PCR sensitivity was reduced in ram and buck semen suggesting the presence of potential PCR inhibitors. Of 304 bull semen samples, the 16S PCR revealed DNA of chlamydiae in 20 samples (6.6%), including Cp. abortus (n=2), Cp. psittaci (n=1), Chlamydia suis (n=2), and Chlamydia-like organisms (n=15). In rams, one semen sample was positive for Chlamydia-like organism. All investigated male genital organs were negative for Chlamydia. Serology revealed 47.1% (49/104) positive bulls by LPS ELISA. Of these, 30 samples were positive by rMOMP ELISA, predominantly for Cp. pecorum. In small ruminants, cELISA displayed 34.8% (16/46) and 60% (9/15) positivity for Cp. abortus in rams and bucks, respectively. There was no correlation between serology and PCR of semen. The presence of chlamydiae in semen suggests the possibility of venereal transmission, although risk may be low in Switzerland.

Detection of chlamydiae in boar semen and genital tracts.

Chlamydiae cause abortion and reproductive disorders in sows. Although organisms can infect the male genital tract, little is known about the disease situation in boars. Hence, we examined the prevalence of chlamydial infection in semen and genital tracts of boars. Samples collected from Swiss boars (group A: n=42), and boars from Germany (group B: n=39) were examined by bacteriology, LPS-ELISA, immunohistochemistry (IHC) and polymerase chain reaction (PCR). The latter methodology involved use of three PCR assays including 16Sig rDNA, IGS-S (intergenic spacer 16S/23S-Short) and IGS-L (intergenic spacer 16S/23S-Long) PCR for comparison methods. PCR sensitivity and the presence of potential PCR inhibitors were determined by spiking semen with Chlamydophila (Cp.) abortus DNA. Detection limits of the 16Sig and IGS-S PCR were 10 templates, while the IGS-L PCR was less sensitive (100 templates). Of 25 semen samples that were collected from group A, one semen sample was positive for Cp. psittaci and two were positive for Chlamydia-like organisms by 16Sig PCR. Screening of sera from Swiss boars revealed three animals with positive reactions in the LPS-ELISA, although we failed to detect chlamydiae within organs of these or sera-negative animals by IHC or IGS-S PCR. In group B, 10 ejaculates were positive for Chlamydia (C.) suis and two were positive for Chlamydia-like organisms by 16S PCR. The identification of DNA from Chlamydia-like organisms in semen from both groups of boars was surprising and a role for these bacteria in reproductive diseases requires further assessment. In conclusion, the prevalence of chlamydial infection was low in group A animals indicating that venereal transmission may not be significant for Chlamydia-associated reproductive diseases in pigs, although rare cases may occur.

Bovine CNS myelin contains neurite growth-inhibitory activity associated with chondroitin sulfate proteoglycans.

The absence of fiber regrowth in the injured mammalian CNS is influenced by several different factors and mechanisms. Besides the nonconducive properties of the glial scar tissue that forms around the lesion site, individual molecules present in CNS myelin and expressed by oligodendrocytes, such as NI-35/NI-250, bNI-220, and myelin-associated glycoprotein (MAG), have been isolated and shown to inhibit axonal growth. Here, we report an additional neurite growth-inhibitory activity purified from bovine spinal cord myelin that is not related to bNI-220 or MAG. This activity can be ascribed to the presence of two chondroitin sulfate proteoglycans (CSPGs), brevican and the brain-specific versican V2 splice variant. Neurite outgrowth of neonatal cerebellar granule cells and of dorsal root ganglion neurons in vitro was strongly inhibited by this myelin fraction enriched in CSPGs. Immunohistochemical staining revealed that brevican and versican V2 are present on the surfaces of differentiated oligodendrocytes. We provide evidence that treatment of oligodendrocytes with the proteoglycan synthesis inhibitors beta-xylosides can strongly influence the growth permissiveness of oligodendrocytes. beta-Xylosides abolished cell surface presentation of brevican and versican V2 and reversed growth cone collapse in encounters with oligodendrocytes as demonstrated by time-lapse video microscopy. Instead, growth cones were able to grow along or even into the processes of oligodendrocytes. Our results strongly suggest that brevican and versican V2 are additional components of CNS myelin that contribute to its nonpermissive substrate properties for axonal growth. Expression of these CSPGs on oligodendrocytes may indicate that they participate in the restriction of structural plasticity and regeneration in the adult CNS.