Biomedical subjects

K Lange

Publications and source records attributed to K Lange.

At least 55 records · Page 3Linked to original sources

PubMed1999

Skin penetration and metabolism of topical glucocorticoids in reconstructed epidermis and in excised human skin.

PURPOSE: To investigate pharmacokinetic differences between the nonhalogenated double ester prednicarbate (PC) and the fluorinated monoester betamethasone 17-valerate (BM17V) their metabolism in human keratinocytes and fibroblasts as well as their permeation and biotransformation in reconstructed epidermis and excised human skin was compared. Special attention was given to the 17-monoesters because of their high receptor affinity and antiproliferative effects. METHODS: Glucocorticoid penetration was determined using Franz diffusion cells, quantifying metabolite concentrations by HPLC. Chemical stability and reactivity of the monoesters was determined by molecular modeling analysis. RESULTS: PC accumulated in the stratum corneum. A considerable amount of penetrating PC was hydrolyzed by viable keratinocytes to prednisolone 17-ethylcarbonate (PI7EC), P17EC permeated the skin very rapidly when compared to BM17V. Overall P17EC concentrations in viable tissue were low. Inside of the acceptor fluid, but not within the tissue, P17EC was converted to the more stable prednisolone 21-ethylcarbonate (P21EC). CONCLUSIONS: The inactivation of highly potent, but also cell toxic, 17-monoesters to almost inactive 21-congeners seen with isolated cell monolayers appears less important in the skin. In vitro determination of the dermal 17-monoesters concentrations may allow the prediction of the atrophogenic risk in man. BM17V levels exceeding P17EC concentration about 6-fold may contribute to its lower tolerance when compared to PC.

Administration, Topical↗

PubMed1999

Point and interval estimates of marker location in radiation hybrid mapping.

Radiation hybrid (RH) mapping is a powerful method for ordering loci on chromosomes and for estimating the distances between them. RH mapping is currently used to construct both framework maps, in which all markers are ordered with high confidence (e.g., 1,000:1 relative maximum likelihood), and comprehensive maps, which include markers with less-confident placement. To deal with uncertainty in the order and location of markers, marker positions may be estimated conditional on the most likely marker order, plausible intervals for nonframework markers may be indicated on a framework map, or bins of markers may be constructed. We propose a statistical method for estimating marker position that combines information from all plausible marker orders, gives a measure of uncertainty in location for each marker, and provides an alternative to the current practice of binning. Assuming that the prior distribution for the retention probabilities is uniform and that the marker loci are distributed independently and uniformly on an interval of specified length, we calculate the posterior distribution of marker position for each marker. The median or mean of this distribution provides a point estimate of marker location. An interval estimate of marker location may be constructed either by using the 100(alpha/2) and 100(1-alpha)/2 percentiles of the distribution to form a 100(1-alpha) % posterior credible interval or by calculating the shortest 100(1-alpha) % posterior credible interval. These point and interval estimates take into account ordering uncertainty and do not depend on the assumption of a particular marker order. We evaluate the performance of the estimates on the basis of results from simulated data and illustrate the method with two examples.

Bayes Theorem↗

PubMed1998

Risk of blood contamination of health care workers in spine surgery. A study of 324 cases.

STUDY DESIGN: The relative risk of blood contamination during spine surgery was studied using data collected from 324 procedures. OBJECTIVES: To analyze demographic factors that predict blood-borne pathogens in the population of spine surgery patients, study the rates and patterns of blood contamination in health care workers (i.e., skin-penetrating incidents and nonpenetrating surface skin contamination from patients' blood) and compare those risks with those in other surgical departments, and analyze the effectiveness of barrier systems worn by the surgical team. SUMMARY OF BACKGROUND DATA: The Centers for Disease Control and Prevention has reported 49 health care workers infected by the human immunodeficiency virus through occupational exposure. Several studies have noted the risk of blood contamination in various surgical departments, but the relative risk during spine surgery has not been determined. METHODS: This year-long survey included 9795 cases, or 60,789 health care worker--patient contacts, of which spine disorders comprised 324 cases (2234 health care workers and patients). Data collection forms were designed and inservice training conducted with operating room staffs. Information regarding type of case, staff position (surgeon, assistant, scrub nurse, circulator), protective clothing worn, length of operating room time, blood loss, incidence of blood spills, was recorded, among other data. RESULTS: Prevalence of human immunodeficiency virus in patients in the overall series was 0.19% versus 0.93% in spine patients. The rate of HCW contamination in the overall series was 7.76%, of which 0.92% resulted from skin-penetrating incidents. Contamination in spine surgery occurred in 31.86% of cases, of which 1.23% were the result of skin-penetrating incidents. CONCLUSIONS: Health care workers in spine surgery have a statistically significant overall higher risk of blood contamination than do those in other surgical departments. The increased risk occurred with blood contacting intact skin. There was no higher risk for skin penetrating injury. Analysis of data suggests that health care workers always should wear double gloves, forearm-reinforced gowns, and eye protection.

Blood-Borne Pathogens↗

PubMed1998

Action of insulin on the surface morphology of hepatocytes: role of phosphatidylinositol 3-kinase in insulin-induced shape change of microvilli.

In previous studies we have shown that the insulin-responding glucose transporter isoform of 3T3-L1 adipocytes, GluT4, is almost completely located on microvilli. Furthermore, insulin caused the integration of these microvilli into the plasma membrane, suggesting that insulin-induced stimulation of glucose uptake may be due to the destruction of the cytoskeletal diffusion barrier formed by the actin filament bundle of the microvillar shaft regions [Lange et al. (1990) FEBS Lett. 261, 459-463; Lange et al. (1990) FEBS Lett. 276, 39-41]. Similar shape changes in microvilli were observed when the transport rates of adipocytes were modulated by glucose feeding or starvation. Here we demonstrate that the action of insulin on the surface morphology of hepatocytes is identical to that on 3T3L1 adipocytes; small and narrow microvilli on the surface of unstimulated hepatocytes were rapidly shortened and dilated on top of large domed surface areas. The aspect and mechanism of this effect are closely related to "membrane ruffling" induced by insulin and other growth factors. Pretreatment of hepatocytes with the PI 3-kinase inhibitor wortmannin (100 nM), which completely prevents transport stimulation by insulin in adipocytes and other cell types, also inhibited insulin-induced shape changes in microvilli on the hepatocyte surface. In contrast, vasopressin-induced microvillar shape changes in hepatocytes [Lange et al. (1997) Exp. Cell Res. 234, 486-497] were insensitive to wortmannin pretreatment. These findings indicate that PI 3-kinase products are necessary for stimulation of submembrane microfilament dynamics and that cytoskeletal reorganization is critically involved in insulin stimulation of transport processes. The mechanism of the insulin-induced cytoskeletal reorganization can be explained on the basis of the recent finding of Lu et al. [Biochemistry 35(1996) 14027-14034] that PI 3-kinase products exhibit much higher affinity for the profilin-actin complex than the primary products, PIP and PIP2. Thus, activated PI 3-kinase may direct a flux of profilin-actin complexes to the membrane locations of activated insulin receptors, where, due to the release of actin monomers after binding of profilactin to PI(3,4)P2 and PI(3,4,5)P3, massive actin polymerization is initiated. As a consequence, PI 3-kinase activation initiates a vectorial reorganization of the cellular actin system to membrane sites neighboring activated insulin receptors, giving rise to local membrane stress as visualized by extensive surface deformations and shortening of microvilli. In addition, extensive high-affinity binding of F-actin-barbed endcapping proteins enhances the cytoplasmic concentration of rapidly polymerizing filament ends. Consequently, the actin monomer concentration is lowered and the (cytoplasmic) pointed ends of the microvillar shaft bundle depolymerize and become shorter. The observations presented strengthen the previously postulated diffusion-barrier concept of glucose- and ion-uptake regulation and provide a mechanistic basis for explaining the action of insulin and other growth factors on transport processes across the plasma membrane.

Actins↗

PubMed1998

Characterization of the novel, pediatric Hodgkin disease-derived cell line HKB-1.

BACKGROUND: A novel Hodgkin disease (HD)-derived cell line, designated HKB-1, was established from pulmonary HD of nodular sclerosing subtype of a 14-year-old-girl. PROCEDURE AND RESULTS: Immunophenotypically, HKB-1 cells are of B cell in phenotype, being also positive for markers CD15, CD25 and CD30. Transformation of the cell line by Epstein-Barr virus (EBV) was excluded by failure to detect EBV antigens and EBV DNA in cultured cells. Chromosome studies of HKB-1 showed a pseudodiploid karyotype with complex clonal structural aberrations. The detection of a monoclonal immunoglobulin heavy chain (IgH) gene rearrangement confirmed the derivation of the HKB-1 from the B cell lineage and its monoclonality. HKB-1 produced high amounts of interleukin (IL)-6 as detected in culture supernatant whereas no secretion of IL-1 beta, IL-2, IL-4, IL-10, IL-12 or interferon (IFN)-gamma was detected. CONCLUSIONS: Our studies indicate that this cell line is of tumor origin.

Adolescent↗

PubMed1998

Models for haplotype evolution in a nonstationary population.

Haplotype mapping has emerged in the past few years as a powerful tool for the fine mapping of disease genes. It is typically carried out on a sample of affected individuals from a population isolate. If the chromosome neighborhood of a disease gene is saturated with markers, then each new mutation in the population or existing mutation introduced by a population founder exhibits a unique haplotype signature at the time of its introduction. Partial disruption of these signatures by recombination can be visualized in affects and provide important clues to the location of the disease gene. The current paper models haplotype evolution with the intention of clarifying the most favorable circumstances for haplotype mapping. Comparisons with linkage mapping are stressed. For dominant diseases, both deterministic and stochastic models are suggested. Numerical examples based on Finnish population parameters illustrate the general theory in the presence of the complications of selection, mutation, and slow, exponential growth of the isolate.

Biological Evolution↗

PubMed1998

Primary culture and transfection of epithelial cells of human small intestine.

BACKGROUND: So far, no techniques are available for primary culture and efficient transfection of human small-intestinal enterocytes, which would provide a valuable tool to investigate intestinal function. METHODS: Human small-intestinal biopsy specimens were treated with collagenase and dispase. Resulting crypt units were cultured for several days. Using the intestinal epithelial cell lines Caco-2 and HT-29, we established optimal conditions for transfection of a control plasmid, which were then applied to primary cultured cells. RESULTS: Cells growing out of crypt units formed monolayer-like sheets and proliferated for several days. Most of the cells could be stained with antibodies against epithelial markers. Among seven different transfection reagents tested, Lipofectamine was the most potent, with transfection efficiencies up to 25% for primary enterocytes. CONCLUSIONS: An easy technique was developed providing viable small-intestinal enterocytes that can be efficiently transfected.

Cell Division↗

PubMed1998

Computational advances in maximum likelihood methods for molecular phylogeny.

We have developed a generalization of Kimura's Markov chain model for base substitution at a single nucleotide site. This generalized model incorporates more flexible transition rates and consequently allows irreversible as well as reversible chains. Because the model embodies just the right amount of symmetry, it permits explicit calculation of finite-time transition probabilities and equilibrium distributions. The model also meshes well with maximum likelihood methods for phylogenetic analysis. Quick calculation of likelihoods and their derivatives can be carried out by adapting Baum's forward and backward algorithms from the theory of hidden Markov chains. Analysis of HIV sequence data illustrates the speed of the algorithms on trees with many contemporary taxa. Analysis of some of Lake's data on the origin of the eukaryotic nucleus contrasts the reversible and irreversible versions of the model.

Algorithms↗

PubMed1998

[Effect of various factors on the suckling behavior of domestic rabbits].

An average number of 1.47 suckling events per 24 hours with a mean duration of 203 seconds per suckling was shown in investigations with 156 does (253 litter, 1.907 alive born pups) by continuous video recordings (infrared technique) over 1.045 periods with 24 hours. Two or more suckling periods with maximum of six sucklings per 24 h were recorded in 40% of all days. Number and duration of suckling events and also percentage of days with > or = 2 sucklings/24 hours were significantly influenced by genotype of does, parity and keeping system (flatdeck, get-away-cage). ZIKA-hybrids had the highest percentage of days with several suckling periods (52.7). Suckling activity had shown a circadian rhythm and was significantly correlated with dawn (light-dark as an inducing factor for suckling). 25% of all suckling events took place in the hour after the lights were turned off.

Animals↗

PubMed1997

[Hearing in a geriatric perspective].

To assess whether hearing rehabilitation of older people can be improved by co-operation between the audiology and geriatric departments and the home service, 139 old and frail audiological patients were allocated to three groups with three different fitting procedures: 1) conventional fitting including verification of acoustical gain in the patient's ear; 2) home-fitting by hearing therapists, and 3) home-fitting by a specially trained geriatric nursing assistant, the home help also being present. Outcome was assessed by the ordinary questionnaire mailed to hearing aids users three to four months after fitting and by a geriatric evaluation procedure. The response rate in the conventionally fitted group was highly unsatisfactory (36%) and too small for further data-analysis. In the educational group a tendency was found towards better manipulation skills and significantly higher hearing aid use. However, the response rate was lower than in the geriatric group (71% compared to 81%), and no knowledge of hearing aid use was registered in the home service by this procedure. In the geriatric group a correlation was found between practical ability and use and satisfaction with the hearing aid. However, two thirds of the group were dependent on lasting help for the handling of the aid. Most patients in this group were already known by the hospital and home service, and the individual home help showed an interest in learning about hearing aid use. Home fitting by a joint audiological and geriatric effort in collaboration with the home help has proven feasible and valuable to both patient and home help. Extended co-operation is recommended between the health care and the social sector concerning hearing aid use.

Aged↗

PubMed1997

Activation of calcium signaling in isolated rat hepatocytes is accompanied by shape changes of microvilli.

Preceding studies using the hamster insulinoma cell line, HIT, and isolated rat hepatocytes have shown that two essential components of the Ca2+ signaling pathway, the ATP-dependent Ca2+ store and the store-coupled Ca2+ influx pathway, are both located in microvilli covering the surface of these cells. Microvilli-derived vesicles from both cell types exhibited anion and cation pathways which could be inhibited by anion and cation channel-specific inhibitors. These findings suggested that the microvillar tip compartment forms a space which is freely accessible for external Ca2+, ATP, and IP3. The entry of Ca2+ into the cytoplasm, however, is largely restricted by the microvillar core structure, the dense bundle of actin microfilaments acting as a diffusion barrier between the microvillar tip compartment and the cell body. Moreover, evidence has been presented that F-actin may function as ATP-dependent and IP3-sensitive Ca2+ store that can be emptied by profilin-induced depolymerization or reorganization [K. Lange and U. Brandt (1996) FEBS Lett. 395, 137-142]. Here we demonstrate the tight connection between microvillar shape changes and the activation of the Ca2+ signaling system in isolated rat hepatocytes. Using a combination of scanning electron microscopy (SEM) and fura-2 fluorescence technique, we confirmed a consequence of the "diffusion barrier" concept of Ca2+ signaling: Irrespective of the type of the applied stimulus, activation of the Ca2+ influx pathway is accompanied by changes in the structural organization of microvilli indicative of the loss of their diffusion barrier function. We further show that the cell surfaces of unstimulated hepatocytes isolated by either the collagenase or the EDTA perfusion technique are densely covered with microvilli predominantly of a short and slender type. Beside this rather uniformly shaped type of microvilli, a number of dilated surface protrusions were observed. Under these conditions the cells displayed the well known rather high basal [Ca2+]i of 200-250 nM as repeatedly demonstrated for freshly isolated hepatocytes. However, addition of the serine protease inhibitor, phenylmethanesulfonyl fluoride (PMSF), to the cell suspension immediately after its preparation reduced the basal cytoplasmic Ca2+ level to about 100 nM. Concomitantly, dilated surface protrusions disappeared, and cell surfaces exclusively displayed short, slender microvilli. Activation of the Ca2+ signaling pathway by vasopressin, as well as by the IP3-independent acting Ca2+ store inhibitor, thapsigargin, was accompanied by a conspicuous shortening and dilation of microvilli following the same time courses as the respective increases of [Ca2+]i induced by the effectors. Furthermore, the abundance of the large form of surface protrusions on isolated hepatocytes positively correlated with the size of a cellular Ca2+/Fura-2 compartment which is rapidly depleted from Ca2+ by extracellular EGTA. These findings support the postulated localization of the store-coupled Ca2+ influx pathway in microvilli of HIT cells also for hepatocytes and are in accord with the notion of a cytoskeletal diffusion barrier regulating the flux of external Ca2+ via the microvillar tip region in the cytoplasm.

Animals↗

PubMed1997

Prostate cancer susceptibility locus on chromosome 1q: a confirmatory study.

BACKGROUND: Recent recognition that a predisposition to prostate cancer can be inherited has led to a search for specific genes associated with the disease. Through a study of families with three or more affected first-degree relatives, a region on the long arm of chromosome 1 (i.e., 1q24-25) has been tentatively identified as containing a gene, HPC1, involved in the development of hereditary prostate cancer. Confirmation of this finding is needed, however, before attempts are made to isolate and characterize the putative HPC1 gene. PURPOSE: To confirm that chromosome 1q24-25 contains a gene relevant to hereditary prostate cancer, we analyzed an independent set of families, each with two or more affected individuals. METHODS: Fifty-nine unrelated families were selected for analysis on the sole criterion that more than one living family member was affected by prostate cancer. DNA samples were subsequently isolated from 130 individuals with the disease. These samples were genotyped at six polymorphic marker sequences (D1S215, D1S2883, D1S466, D1S158, D1S518, and D1S2757) covering the chromosomal region proposed to contain HPC1. The resulting data were analyzed by nonparametric multipoint linkage (NPL) methods, yielding NPL Z scores and corresponding one-sided P values. RESULTS: When the entire set of 59 families was considered, the occurrence of prostate cancer (and, presumably, the HPC1 gene) was most tightly linked to marker D1S466 (NPL Z score = 1.58; P = .0574). Analysis of the 20 families (51 affected individuals) fulfilling one or more of the proposed clinical criteria for hereditary prostate cancer (i.e., three or more affected individuals within one nuclear family; affected individuals in three successive generations [maternal or paternal lineage]; and/or clustering of two or more individuals affected before the age of 55 years) revealed more convincing evidence of disease linkage to chromosome 1q24-25 (maximum NPL Z score [at marker D1S466] = 1.72; P = .0451). The 39 families (79 affected individuals) that did not meet the clinical criteria for hereditary prostate cancer exhibited no significant evidence of disease linkage to DNA sequences at chromosome 1q24-25 (maximum NPL Z score [at marker D1S466] = 0.809; P = .208). The six African-American families in our study contributed disproportionately to the observation of linkage, with a maximum NPL Z score at marker D1S158 of 1.39 (P = .0848) for these families. CONCLUSIONS AND IMPLICATIONS: Our data confirm that chromosome 1q24-25 is likely to contain a prostate cancer susceptibility gene. Future efforts at positional cloning of the HPC1 gene should focus on families who meet the proposed clinical criteria for hereditary prostate cancer.

Adult↗

PubMed1997

A new concept for risk assessment of the hazards of non-genotoxic chemicals--electronmicroscopic studies of the cell surface. Evidence for the action of lipophilic chemicals on the Ca2+ signaling system.

Recently, we presented evidence for the localization of components of the cellular Ca2+ signaling pathway in microvilli. On stimulation of this pathway, microvilli undergo characteristic morphological changes which can be detected by scanning electron microscopy (SEM) of the cell surface. Here we show that both receptor-mediated (vasopressin) and unspecific stimulation of the Ca2+ signaling system by the lipophilic tumor promoters thapsigargin (TG) and phorbolmyristateacetate (PMA) are accompanied by the same type of morphological changes of the cell surface. Since stimulated cell proliferation accelerates tumor development and sustained elevation of the intracellular Ca2+ concentrations is a precondition for stimulated cell proliferation, activated Ca2+ signaling is one possible mechanism of non-genomic tumor promotion. Using isolated rat hepatocytes we show that all tested lipophilic chemicals with known tumor promoter action, caused characteristic microvillar shape changes. On the other hand, lipophilic solvents that were used as differentiating agents in cell cultures such as dimethylsulfoxide (DMSO) and dimethylformamide also, failed to change the microvillar shapes. Instead DMSO stabilized the original appearance of microvilli. The used technique provides a convenient method for the evaluation of non-genomic carcinogenicity of chemicals prior to their industrial application.

Alkanes↗

PubMed1997

The role of early HIV infection in the spread of HIV through populations.

The combination of two factors gives early HIV infection an especially strong influence on transmission dynamics: (a) increased transmission probabilities and (b) increased transmission potential of partners infected during this period. Most attention has been focused on the first factor because it fits the way we usually think about risk factors affecting individuals. The second factor acts not on individuals, but across chains of transmission. It is missed by models with constant partnership formation rates over an individual's life or with random mixing. It cannot be assessed from available data collected from individuals. Its assessment requires data from both individuals in a partnership. We demonstrate that this second effect can be so strong that early infection can dominate transmission dynamics even when transmission probabilities are only modestly increased. This second effect is not directly parameterized in our models but arises from two realistic types of temporal variation in partnership formation: (a) Partnership formation rates vary by age with preferential partnership formation in one's own age group, and (b) individuals of any age can experience transient periods of high-risk partnership formation. In a model with only the age-related effect, early infection is observed to dominate transmission dynamics when 20% of transmissible virus is allocated to the first 6 weeks of infection, 7% to middle infection, and 73% to late infection. This domination occurs both early in the course of an epidemic and later when endemic infection levels have been reached. When the second effect is added, early infection is seen to dominate transmission in a model allocating 10% of transmissible virus to the first 6 months, 40% to middle infection, and 50% to late infection. In this model, transmission probabilities during early infection are only 4.17 times those of middle infection and half those of late-stage infection.

Age Factors↗

PubMed1997

[123I]beta-CIT single-photon emission tomography in DOPA-responsive dystonia.

The radiotracer [123I]beta-CIT is a sensitive marker of dopamine uptake sites that can be used to visualize dopaminergic nerve endings in vivo in the human brain. We report on [123I]beta-CIT single-photon emission computed tomography (SPECT) findings in a patient with DOPA-responsive dystonia (DRD). [123I]beta-CIT SPECT showed a striatal radiotracer uptake in the upper range of normal, indicating intact dopamine transporters and structural integrity of nigrostriatal neurons. This differentiates DRD from clinically similar cases with juvenile-onset parkinsonism with dystonia that have a considerable poorer prognosis. [123I]-beta-CIT SPECT may provide a method equally as useful as fluorodopa positron emission tomography in DRD.

Adult↗

PubMed1997

Branching process models for mutant genes in nonstationary populations.

A deleterious gene achieves a population balance between the opposing forces of selection and mutation. In this paper we explore the nature of this stochastic balance when the surrounding normal population is not at equilibrium. Assuming that new mutations occur according to a Poisson process and thereafter evolve by the rules of a continuous time branching process, we derive explicit formulas and recurrence relations determining the probability distribution of the current number of mutant individuals. In fact, we compute expectations for a variety of interesting random variables for genetic models involving autosomal dominant and X-linked diseases. We can also handle haplotype information on linked markers. This feature will be especially helpful in understanding the linkage disequilibrium strategy of positional cloning in population isolates. In the presence of exponential growth of the normal population, our formulas reduce to the evaluation of certain Laplace transforms.

Female↗

PubMed1997

The contribution of newly synthesized cholesterol to biliary cholesterol in healthy humans.

Hypersecretion of biliary cholesterol appears to be the key defect in the pathogenesis of cholesterol gallstones, and this may be due to an enhanced synthesis of cholesterol. To measure fractional syntheses of biliary and plasma cholesterol, five male and 3 female healthy humans with an intact enterohepatic circulation were infused intravenously with [1-13C]acetate for 15 h. Samples of duodenal bile and blood were taken hourly and an enteral formula diet was given. Free cholesterol mass distribution was analyzed by gas chromatography mass spectrometry. The Mass Isotopomer Distribution Analysis (MIDA) technique allowed to calculate fractional synthesis. After 6 hours of infusion, the [13C]label of the cytosolic acetate pool reached a plateau of approximately 12%. Individual fractional cholesterol synthesis is plasma and bile correlated significantly (6-15 h) and amounted to 4.2% and 5.3% after 15 h, respectively. It may be concluded from this study, that newly synthesized cholesterol is secreted into bile to a higher extent than into plasma.

Acetates↗

PubMed1997

[MRI arthrography--improved diagnosis of shoulder joint instability].

In a prospective study, we examined 34 patients with shoulder instabilities and 5 patients with unclear chronic shoulder pain (4 females, 35 males; 18-56 years of age, median 28 years) by CT arthrography and MRT arthrography from August 1994 through December 1995. No complications were seen when gadolinium-DPTA was applied intra-articularly. Twenty-three patients were followed up by operation and/or arthroscopy; 20 patients underwent a modified, open Bankart operation. In this paper, we present a new classification for damage of the anterior capsule and labrum. MRT arthrography showed better results in judging the anterior labrum and in determining the degree of damage to the labrum (sensitivity, specificity and accuracy 100%) in comparison with CT arthrography (sensitivity 90%, specificity 100%, accuracy 91%). Furthermore, MRT arthrography gave clearer results than CT arthrography regarding SLAP and cartilage lesions. Thus, MRT arthrography has proved to be a very exact method for diagnosing shoulder instabilities and is superior to CT arthrography in diagnostic accuracy.

Adolescent↗