Video-assisted laryngoscopy: a useful adjunct in endotracheal intubation

The difficult airway is the single most important cause of anaesthesia-related morbidity and mortality and most catastrophes are due to unexpected difficulty, which are more likely in emergencies. We report a difficult airway scenario in a patient with a high energetic trauma and used several techniques for the "can't intubate, can't ventilate scenario". Eventually, successful intubation was obtained with the video-assisted laryngoscope.

Altered distribution and levels of cathepsinD and cystatins in amyotrophic lateral sclerosis transgenic mice: Possible roles in motor neuron survival

In amyotrophic lateral sclerosis (ALS) there is a selective degeneration of motor neurons leading to muscle paralysis and death. The mechanism underlying cell demise in ALS is not fully understood, but involves the activation of different proteolytic enzymes, including the caspase family of cysteine proteases. We have here studied whether other proteases, such as the cathepsins, residing in lysosomes, and the cathepsin inhibitors, cystatinB and -C are changed in ALS. The expression and protein levels of the cathepsinB, -L and -D all increased in the spinal cord in ALS mice, carrying the mutant copper/zinc superoxide dismutase (SOD1) gene. At the cellular level, cathepsinB and -L were present in ventral motor neurons in controls, but in the ALS mice cathepsinB was also expressed by glial fibrillary acidic protein (GFAP) positive astrocytes. The distribution of the aspartic protease, cathepsinD also changed in ALS with a loss of the lysosomal staining in motor neurons. Inhibition of caspases by means of X-chromosome-linked inhibitor of apoptosis protein (XIAP) overexpression did not inhibit cleavage of cathepsinD in ALS mice, suggesting a caspase-independent pathway. Expression of cystatinB and -C increased slightly in the ALS spinal cords. Immunostaining showed that in ALS, cystatinC was present in motor neurons and in GFAP positive astrocytes. CystatinB that is a neuroprotective factor decreased in motor neurons in ALS but was expressed by activated microglial cells. The observed changes in the levels and distributions of cathepsinD and cystatinB and-C indicate a role of these proteins in the degeneration of motor neurons in ALS.

Effects of prepulse intensity, duration, and bandwidth on perceived intensity of startling acoustic stimuli

Intense abrupt stimuli can elicit a startle reflex; a weak "prepulse" 30-300 ms earlier can reduce both startle and perceived stimulus intensity. Prepulse inhibition (PPI) of startle, an operational measure of sensorimotor gating, is used to understand brain disorders characterized by gating deficits. Compared to startle, PPI of perceived stimulus intensity (PPIPSI) may provide information that is distinct, and easier to acquire and analyze. To develop this experimental measure, we examined PPIPSI under different stimulus conditions. Both PPI and PPIPSI exhibited a non-linear relationship to prepulse intensity, with prepulses 15 dB(A) above background causing maximal inhibition of both measures. A 50 ms broadband noise prepulse produced maximal PPI and PPIPSI, whereas 5 and 20 ms pure tone prepulses produced maximal PPIPSI and PPI, respectively. PPIPSI is a robust, parametrically sensitive and "low tech" measure of sensory gating that may become a valuable tool for understanding the biology of certain mental disorders.

Biological and prognostic role of acid cysteine proteinase inhibitor (ACPI, cystatin A) in non-small-cell lung cancer

BACKGROUND

Acid cysteine protease inhibitor (ACPI) is an intracellular protein, often linked to neoplastic changes in epithelium and thought to have an inhibitory role in malignant transformation.

AIM

To analyse the expression and prognostic role of ACPI in non-small-cell lung cancer (NSCLC).

METHOD

Histological samples from 199 patients with resected NSCLC were stained immunohistochemically for the expression of ACPI in normal and preneoplastic bronchial epithelium, and in various types of lung carcinomas.

RESULTS

A normal bronchial epithelium showed positive staining for ACPI in the basal cells, whereas the upper two-thirds of the dysplastic epithelium was ACPI positive. High staining for ACPI was found in 74% (91/123) of squamous-cell carcinomas, whereas 16% (8/49) of adenocarcinomas and 30% of (8/27) large-cell carcinomas showed the high expression of ACPI (p<0.001). Among squamous-cell carcinomas, low expression of ACPI was correlated with poor tumour differentiation (p=0.032). In the whole tissue, reduced expression of ACPI was associated with tumour recurrence (p=0.024). In overall survival (OS) and disease-free survival (DFS) analyses, the histological type of the tumour (both p<0.001) and stage of the tumour (p=0.001, p=0.013, respectively) were related to patient outcome. Low expression of ACPI in tumour cells was associated with poor OS and DFS (p<0.041, p=0.004, respectively). In multivariate analysis, ACPI did not retain its prognostic value, whereas the traditional factors were the most important prognostic factors.

CONCLUSIONS

ACPI expression is linked with the malignant transformation of the bronchial epithelium and predicts a risk of tumour recurrence as well as poor rate of survival for the patients. However, ACPI does not have any independent prognostic value in NSCLC.

Personal communicator

An assistive technology (AT) device was originally created for a young child who has difficulty communicating. The child is not able to talk and is not old enough to read yet. This rules out conventional communication devices that this child could use to communicate. A device was requested by the child's educator that would talk for the child. Originally it needed to be wristwatch size and able to visually cue the child so that the child would know what was going to be said. The project's first prototype was built by a senior design student. Although the basic features of the prototype functioned properly, it was not practical for day to day use. Originally a rebuild was requested by the educator but after further investigation it was decided that a new design was needed so that it could better cue the child. A new device was built using a high resolution graphic liquid crystal display (LCD), a voice recording chip and a microcontroller. The wristwatch size requirement was changed to meet available technology and the device was packaged to be used on a lanyard.

Further safety enhancement of a specialized power assisted tricycle for a child with osteogenesis imperfecta type III and design of an adjustble hand power tricycle

Several tricycles, one a customized power assisted tricycle, and the second a hand powered tricycle were developed, which offered a unique opportunity to serve multiple purposes in several children's development throughout Wyoming. In Both cases these tricycles provide the children with the opportunity to gain muscle mass, strength, coordination, and confidence. The power assisted tricycle was completed as a senior design project in 2002, and over time safety enhancements have been completed to make the tricycle safer for operation. Unfortunately, the safety system enhancements were not acceptable for it to be released for use. For this reason the tricycle was further redesigned to include more redundant safety systems which will allow the tricycle to be safe for the child's use. The second tricycle was designed to allow for a group of children who have limited use of their legs, to be able to use the same tricycle to give them more upper body strength. A gear system using multiple gear sprockets was adapted to a preexisting tricycle to provide hand power rather than foot power. Without these improvements, the children would not have the opportunity to use these tricycles to help with their development.

Novel amphiphiles with preorganized functionalities-formation of Langmuir-films and efficiency in mineral flotation

Based on the principle of supramolecular preorganization, three different types of new oligofunctional surfactants have been designed and prepared differing in both the degree of conformational flexibility and the hydrophilic-lipophilic balance of their structures due to the chosen building blocks including rather rigid and shape-persistent backbones or a dendritic subunit. Surface-active properties of the oligofunctional surfactants involving critical micellization concentration, surface tension at cmc, effectiveness of surface tension reduction, and the efficiency of adsorption were determined by use of the surface tension isotherms, respectively. In particular the amino-acid-based amphiphiles show remarkable surface-active properties with the adsorption at the air/water interface and also the aggregation to micelles starting at very low concentration. By analysis of the surface pressure-surface area isotherms interesting information on the packing behavior and orientation of the amphiphilic molecules in relation to the molecular structure could be obtained. Moreover, limiting area and collapse pressure of the Langmuir-films were determined. Morphological observation of the dynamic process of monolayer compression at the air/water interface was carried out by Brewster angle microscopy illustrating several phase states visualized as snap shots. Furthermore, the effectiveness of the new surfactants acting as collecting agents in the process of flotation using the model mineral fluorite was studied. A surprisingly high recovery of the mineral was obtained for the surfactants with constricted flexibility. The flotation plots clearly manifest that bundling of surfactant subunits by tethering to an aromatic core or by dendritic branching is profitable, indicating that effects of preorganization of the oligofunctional surfactant molecules are important.

Hyaluronan and sulphated hyaluronan micropatterns: effect of chemical and topographic cues on lymphatic endothelial cell alignment and proliferation

While tissue engineered blood vessels have entered surgical practice, the construction of artificial lymphatic vessels has never been attempted due to the small dimensions and fragility of lymphatic vessels. A possible alternative would be to obtain a new growth of interrupted lymphatic vessels. We have previously reported that lymphatic endothelial cells align when cultured on striped micropatterns of hyaluronan (Hyal) and aminosilanized glass. We here report a comparative study in which lymphatic endothelial cells have been plated on micropatterns with stripes of different width and height obtained by the photoimmobilization of Hyal and its sulphated derivative (HyalS) on aminosilanized glass to verify whether their response correlated with surface-chemistry andlor topography. On Hyal micropatterns, cells adhered to aminosilanized glass, avoiding Hyal stripes and molding their shape in accordance to the micropattern topography. Stress fibers, integrins and focal adhesion kinase organized accordingly. HyalS micropatterns with the same topography were unable to guide cell response, cells randomly adhered to HyalS and glass stripes, and polarization was attained only by increasing stripe height. These data indicate that surface chemistry is the main cue responsible for lymphatic endothelial cell guidance. When surface chemistry of stripes promotes cell adhesion as well as that of the substrate, topographical parameters become prevalent. Micropatterns with defined chemical and topographical properties may contribute to the design of new platforms for controlled cell growth in tissue engineering of lymphatic vessels.

An in vitro study to compare 99mTc-stannous colloids and 99mTc-HMPAO for labelling human leukocytes

AIM

Aim of the present study was to compare in vitro the labelling efficiency (LE) and cell viability (TBE) of autologous leukocytes labelled with (99m)Tc-SnF(2) and (99m)Tc-HMPAO, and to evaluate the quantity and quality of spontaneously released (99m)Tc (SR) from labelled cells at several time points after labelling.

METHODS

A total of 14 patients with different diseases and 18 normal subjects were included in this study. A blood sample was collected from each patient; purified autologous leukocytes were divided into 2 samples and labelled with (99m)Tc-SnF(2) and (99m)Tc-HMPAO. LE was evaluated at the end of labelling and TBE and SR were evaluated at 10 min and 1 h, 2 h and 4 h after labelling.

RESULTS

LE of (99m)Tc-SnF(2)-WBC was higher than (99m)Tc-HMPAO-WBC (61.2+/-18.7% and 43.3+/-11.3; p<0.0001) and we found an inverse correlation between blood glucose and labelling efficiency for both methods (p=0.02). Minimal differences were also observed between 2 methods after 10 min and 1 h, as far as the cell viability is concerned. The percentage of radioactivity spontaneously released from (99m)Tc-SnF(2)-WBC was significantly higher compared to (99m)Tc-HMPAO-WBC at each time point. Radioactivity released from labelled cells was predominantly (99m)Tc-SnF(2) and (99m)Tc-HMPAO with few free (99m)Tc (<20%).

CONCLUSION

Both radiopharmaceuticals are not toxic for WBC. Labelling with (99m)Tc-SnF(2) give a higher LE than with (99m)Tc-HMPAO; however, radiolabelled colloids are more released from labelled cells over a period of 4 h. While (99m)Tc-HMPAO is physiological excreted into gastrointestinal tract, (99m)Tc-SnF(2) can be re-uptaken in vivo by reticulo-endothelial cells of liver and spleen. These findings suggest that (99m)Tc-SnF(2)-WBC might be better than (99m)Tc-HMPAO-WBC for studying inflammatory bowel diseases.

The pattern of fibrillin deposition correlates with microfibril-associated glycoprotein 1 (MAGP-1) expression in cultured blood and lymphatic endothelial cells

Fibrillins constitute the major structural components of 10-12nm microfibrils of the extracellular matrix of several elastic and non elastic tissues and of initial lymphatic vessel anchoring filaments. Microfibril-Associated Glycoprotein-1 (MAGP-1) binds fibrillin to tropoelastin during elastogenesis. We recently reported that cultured blood endothelial cells deposit fibrillin in a honeycomb pattern, whereas lymphatic endothelial cells form an irregular web. The aim of this immunohistochemical study was to verify whether the deposition pattern of fibrillin is related to the expression of MAGP-1 in confluent and postconfluent cultures of bovine aortic (AEC), pulmonary artery (PAEC) and lymphatic endothelial cells (LEC). In AEC and PAEC, MAGP-1 and fibrillin co-localized and their deposition increased with time in culture. In AEC, both proteins formed a honeycomb pattern. In LEC, MAGP-1 deposition was still negligible when fibrillin formed an irregular web covering the entire surface. PAEC, which in vivo are exposed to physiological conditions intermediate between AEC and LEC, had an intermediate pattern of deposition of fibrillin and MAGP-1. Assuming that early elastogenesis is an intrinsic functional need for the aorta, but not for the thoracic duct, we propose that delayed appearance of MAGP-1 in LEC may correlate with their irregular fibrillin deposition. Different fibrillin scaffolds could in turn account for the specificity of elastic fibers in compliance with the specific functional requirements of the tissue.

Seasonality in clinical onset of type 1 diabetes in belgian patients above the age of 10 is restricted to HLA-DQ2/DQ8-negative males, which explains the male to female excess in incidence

AIMS/HYPOTHESIS

Type 1 diabetes arises from an interplay between environmental and genetic factors. The reported seasonality at diagnosis supports the hypothesis that currently unknown external triggers play a role in the onset of the disease. We investigated whether a seasonal pattern is observed at diagnosis in Belgian Type 1 diabetic patients, and if so whether seasonality varies according to age, sex and genetic risk, all known to affect the incidence of Type 1 diabetes.

METHODS

The seasonal pattern at clinical diagnosis was assessed in 2176 islet antibody-positive diabetic patients aged 0 to 39 years diagnosed between 1989 and 2000. Additional stratification was performed for age, sex and HLA-DQ genotype.

RESULTS

Overall, a significant seasonal pattern at clinical diagnosis of diabetes was observed (p<0.001). More subjects were diagnosed in the period of November to February (n=829) than during the period of June to September (n=619) characterised by higher averages of maximal daily temperature and daily hours of sunshine. However, the seasonal pattern was restricted to patients diagnosed above the age of 10 (0-9 years: p=0.398; 10-19 years: p<0.001; 20-29 years: p=0.003; 30-39 years: p=0.015). Since older age at diagnosis is associated with a male to female excess and a lower prevalence of the genetic accelerator HLA-DQ2/DQ8, we further stratified the patients aged 10 to 39 years (n=1675) according to HLA-DQ genotype and sex, and we found that the seasonal pattern was largely restricted to male subjects lacking DQ2/DQ8 (n=748; p<0.00 vs all others: n=927; p=0.031).

CONCLUSIONS/INTERPRETATION

In a subgroup of male patients diagnosed over the age of 10, the later stages of the subclinical disease process may be more driven by sex- and season-dependent external factors than in younger, female and genetically more susceptible subjects. These factors may explain the male to female excess in diabetes diagnosed in early adulthood.

Micropatterned hyaluronan surfaces promote lymphatic endothelial cell alignment and orient their growth

The implant of a biocompatible device capable of guiding lymphatic vessel regeneration in patients who underwent removal of lymph nodes might contribute to restoring an efficient lymphatic drainage and help to prevent the occurrence of lymphedema. The aim of this study was to evaluate whether a microstructured surface could provide a guidance for the growth of cultured lymphatic endothelial cells. The presence of microstructures on a surface permits the control of cell adhesion, migration, proliferation, and differentiation. We report here that lymphatic endothelial cells align on microstructures of alternating hyaluronan and aminosylanized glass stripes obtained by photoimmobilization. Cells consistently spread and proliferate only on aminosylanized glass. They orient parallel to the longitudinal axis of the stripe. A pattern of alternating stripes of aminosylanized glass uniformly covered by elongated cells and of hyaluronan devoid of cells eventuallyforms. The presence of alpha(v)-integrins along cell borders of cells in search of contact with each other and at the leading edge of migrating cells, sites where new focal adhesions are presumably formed, indicates that integrin-mediated adhesion to the substrate guides cell migration along the microstructure. Micropatterned surfaces of hyaluronan thus proved to adequately orient the growth of cells allowing the regeneration of lymphatic endothelium in the desired direction.

Crystal structure of 2'H,7'H-dispiro[fluorene-9,2'-dibenzo[c,e]- oxepine-7',9"-fluorene], C38H24O

C38H24O, monoclinic, P121/n1 (No. 14), a = 10.737(2) Å, b = 16.963(3) Å, c = 15.246(3) Å, β = 109.30(3)°, V = 2620.8 Å3, Z = 4, Rgt(F) = 0.088, wRref(F2) = 0.252, T = 293 K.

Mapping of quantitative trait loci determining agronomic important characters in hexaploid wheat ( Triticum aestivum L.)

A set of 114 recombinant inbred lines of the 'International Triticeae Mapping Initiative' mapping population was grown during the seasons 1997, 1998, 1999 and 2000 under several environments. Twenty morphological (glume colour, awn colour, waxiness, leaf erectness, peduncle length), agronomical (ear emergence time, flowering time, grain filling time, ear length, plant height, lodging, grain number, thousand-grain-weight, grain weight per ear, grain protein content, winter hardiness) and disease resistance (powdery mildew, yellow rust, leaf rust, fusarium) traits were studied. Not all traits were scored in each experiment. In total 210 QTLs with a LOD threshold of >2.0 (minor QTLs) were detected of which 64 reached a LOD score of >3.0 (major QTLs). Often QTLs were detected in comparable positions in different experiments. Homologous and homoeologous relationships of the detected QTLs, and already described major genes or QTLs determining the same traits in wheat or other Triticeae members, are discussed.

Expression of cathepsins B, H, K, L, and S during human fetal lung development

Cathepsins are involved in lysosomal protein degradation, proenzyme activation, antigen processing, and hormone maturation. They are secreted by tumor cells and macrophages and catalyze the remodeling of extracellular matrix proteins. To gain insight into the expression pattern of cathepsins during fetal lung development, the expression of cathepsins B, H, K, L, and S at protein and mRNA levels were evaluated by using immunohistochemistry and in situ hybridization. Early expression of cathepsins B, H, and K was found in epithelial cells of the branching presumptive bronchi (<12th week of gestation). The most intense cathepsin K-specific immunoreactivity was found in developing airways with a lumen. Cathepsin K was found in epithelial cells only, whereas in contrast, cathepsins B and H were detected both in epithelial and interstitial cells. During fetal maturation, interstitial cells displayed cathepsin L immunoreactivity and, in the saccular phase (>26th week of gestation), both cathepsin L and S immunoreactivities. A continuous decline in the proportion of cathepsin H-positive interstitial CD68-positive cells was observed. These discrete temporal and spatial variations in cathepsin expression during organogenesis of the human lung indicate different physiological roles for the individual enzymes in different cell types and developmental stages.

Expression of cathepsin B, D and L protein in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common childhood autoimmune rheumatic disease and like rheumatoid arthritis (RA), it is characterized by inflammation and the progressive destruction of joints. In RA, cathepsins as proteinases play a major role in destroying synovial tissue and cartilage matrix. So far no data on cathepsin expression in pannus tissue of HA patients exist. The aim of this study was to characterize the expression levels of cathepsins B, D, H, and L in HA and to compare them with those in RA. Synovectomy tissue from 16 HA and 12 RA patients was investigated for cathepsin expression levels by Western blot analysis. Expression of cathepsins B, D and L was on comparable levels in the synovectomy tissue of HA and RA patients. The following graduation of expression was determined: cathepsin D > cathepsin L > cathepsin B. Cathepsin H was neither found to be expressed in HA nor in RA patients. The expression levels of cathepsins in pannus tissue showed no clear difference between patients with systemic JIA and patients with monoarticular JIA. In summary, the comparable expression of cathepsins B, D and L in RA and JIA synovectomy tissue suggests that they may play a similarly important role in destroying synovial tissue and cartilage matrix in the course of HA and RA.

Phenotypic alterations and IL-1beta production in CD34(+) progenitor- and monocyte-derived dendritic cells after exposure to allergens: a comparative analysis

Dendritic cells (DC) have been shown to capture and process antigens and play an initiating role in contact sensitization. Cells with dendritic morphology can be generated in vitro either from CD34(+) cord blood cells or from CD14(+) peripheral monocytes. The aim of this study was to determine the state of maturation/activation of both populations after exposure to several concentrations of four well-established model allergens (nickel sulfate, eugenol, alpha-hexylcinnamaldehyde and 2,4,6-trinitrobenzene sulfonic acid) or the irritant sodium dodecyl sulfate. We analyzed the surface expression of CD86, CD83 and HLA-DR and the production of IL-1beta. DC from the two sources were generated separately in two laboratories, but challenged using identical test protocols. Using both DC populations it was possible to detect the allergens under investigation, though minor differences regarding effective concentrations were noted. The non-responsiveness of CD34-DC to CIN was probably due to non-optimal concentrations. Ni(2+), known as a moderate allergen in vivo, showed the most prominent effect in both cell systems. CD86 expression was the most reliable phenotypic marker for the in vitro identification of allergens. Due to substantial individual variations it was difficult to draw any definite conclusions as to the relevance of IL-1beta production as an activation endpoint. We conclude that both test systems are able to respond to allergens, but CD34-DC must be exposed to higher concentrations to demonstrate significant phenotypic changes. On the other hand, Mo-DC from only some of the donors reacted to allergens, in contrast to CD34-DC, which responded to allergens irrespective of the donor, thus necessitating the use of Mo-DC cultures from several blood donors.

Investigation of crossover interference in barley ( Hordeum vulgare L.) using the coefficient of coincidence

Interference, the interaction between recombination events, was analysed in seven mapping populations of barley ( Hordeum vulgare L.). The coefficient of coincidence was applied to investigate the type and position of interference within the genome. Interference was analysed with respect to dependence on the recombination fraction, and simulations were used to obtain test statistics which consider the small sample size of 71-150 double haploid lines. In addition to positive interference in intermediate intervals, strong negative interference, i.e. encouraged double recombination, was found in short intervals. The relationship between recombination fraction and interference could not be described with a uniform function, neither for the entire genome nor for individual chromosomes. The analysis of the position of interference within the genome revealed that interference does not act in the same way in the whole genome. Intervals spanning the centromere exhibited significantly higher means for the coefficient of coincidence than intervals within the chromosome arms, especially with regard to small intervals. In general, positive interference was found in the chromosome arms and no or negative interference in the genetically small but physically large centromeric region.

Prevalence and recognition of depressive symptoms among homebound older adults with urinary incontinence

Within a group of homebound elders with urinary incontinence, the objectives of this study were to (1) examine the prevalence of depressive symptoms, (2) examine the extent to which depression had previously been recognized by health care providers, (3) describe the type and intensity of antidepressant treatment prescribed for subjects, and (4) identify the demographic and functional characteristics associated with depressive symptomatology. A descriptive correlational design was used. The 15-item Geriatric Depression Scale (GDS-15) was administered to 345 homebound adults age 60 years and over referred to a study examining the effectiveness of behavioral therapy for urinary incontinence. Individuals were referred to the study by home care nurses from two large Medicare-approved home health agencies in a large metropolitan county in Pennsylvania. Data were collected during in-home assessments and by chart review. Measures included the GDS-15, structured medical history, in-home review of medications, Older Americans Research and Service Center Physical and Instrumental Activities of Daily Living scales, Mini-Mental State Examination (MMSE), Clock Drawing Test, Performance-Based Toileting Assessment, and bladder diaries. One half of the participants (n = 173; 50.1%) had significant depressive symptomatology, with 35.7% having scores suggesting mild depression and 14.5% severe depression. Only 26.4% and 34.7% of those with mild and severe depressive symptoms, respectively, had a previous diagnosis of depression and only 21.7% and 34.0%, respectively, had been prescribed an antidepressant. The most commonly prescribed class of antidepressants was tricyclic antidepressants, being taken by 9.0% (n = 31) of the total sample, 14 (11.4%) of those with mild symptoms and 4 (8.0%) of those with severe depressive symptomatology. A little over half (60.0%) of subjects being treated with antidepressants continued to exhibit significant depressive symptomatology. Greater dependence in physical activities of daily living, the need for assistance during ambulation, higher MMSE scores, and higher levels of comorbidity were associated (P < .05) with a GDS-15 score of 5 or higher. Depression symptoms are common in homebound older adults with urinary incontinence, but clinical recognition and treatment are limited.

Cathepsin S and an asparagine-specific endoprotease dominate the proteolytic processing of human myelin basic protein in vitro

The biochemical characterization of antigen degradation is an important basis for a better understanding of both the immune response and autoimmune diseases mediated by MHC class II molecules. In this study we used high-performance liquid chromatography and mass spectrometry to analyze the processing of myelin basic protein (MBP), a potential autoantigen implicated in the pathogenesis of multiple sclerosis. We resolved the kinetics of MBP processing by lysosomal extracts or purified endocytic proteases, identified the major cleavage sites during this process and assigned them to the activity of proteolytic enzymes. Proteolytic processing of MBP is mostly guided along the hydrophobic regions of the protein. It is initiated by two proteolytic steps (after N(92) and S(110)) that are performed by an asparagine-specific endopeptidase (AEP) and by cathepsin (Cat) S, respectively. The resulting processing intermediates are converted into more than 60 different species of 20-40-mers due to the activity of endopeptidases including CatS, D and L. The fragments thus generated are subsequently degraded by C- or N-terminal trimming. Strikingly, the initial cleavages during MBP processing affect two immunodominant regions of the potential autoantigen [MBP(85-99) and MBP(111-129)] in an inverse manner. CatS directly generates the N terminus of the epitope MBP(111-129) in large quantities during the initial phase of processing, which might explain the immunogenicity of this region in spite of its relatively poor binding to HLA-DR4. In contrast, the dominant cleavage by AEP mediates the destruction of MBP(85-99) unless the epitope is protected, e.g. by binding to HLA-DR. Our results thus characterize the proteolytic events during processing of MBP on a molecular level and suggest a biochemical basis for the immunogenicity of the immunodominant epitopes, which could serve as a guideline for future therapeutic strategies.