Biomedical subjects

J Braun

Publications and source records attributed to J Braun.

At least 181 records · Page 10Linked to original sources

PubMed2000

Detailed analyses of periarticular osteoporosis in rheumatoid arthritis.

Periarticular osteopenia is the earliest radiographic sign of rheumatoid arthritis (RA). Recent studies using dual-energy X-ray absorptiometry (DXA) have indicated that the loss of periarticular BMD can be quantified by whole-hand bone mineral density (BMD) measurements. The aim of this study was to analyze periarticular BMD in more detail by DXA and quantitative ultrasound (QUS). In a cross-sectional study 23 women aged 30-76 years with early RA, mean disease duration 26 +/- 19 months, and 18 men aged 42-69 years, mean disease duration 24 +/- 25 months, were examined. All patients received antirheumatic therapy. The reference population consisted of 103 age-matched controls (68 females, 35 males) and young healthy controls. BMD measurements were performed using a DXA Expert XL densitometer (Lunar). BMD of the whole-hand and two subregions was determined: two subchondral regions of interest (S.CH.) were set within the trabecular bone, distal to the proximal interphalangeal joints of digits II and III excluding the dense subchondral bone of the metacarpophalangeal (MCP) joint and two metacarpal regions of interest (MCP) were set including the entire MCP joint of these fingers. QUS measurements at the proximal phalanges of digits II-V were performed using a DBM Sonic (Igea); amplitude-dependent speed of sound (Ad-SoS) was determined. In comparison with whole-hand BMD measurements, bone loss was pronounced in patients with a disease duration of 18-72 months at the subchondral regions of interest in both genders compared with age-matched controls (women: mean BMD loss S.CH. -23%, p<0.001, whole-hand -16%, p<0.001; men: mean BMD loss S.CH. -19%, p < 0.05, whole-hand -12%, p<0.05). The bone changes were also shown by QUS (women: Ad-SOS values of 1950 +/- 90 m/s in RA vs 2137 +/- 35 m/s in young healthy controls (p <0.005); men AD-SOS 1956 +/- 87 m/s in RA vs 2146 +/- 41 m/s in young healthy controls (p <0.05)). These results show that BMD and Ad-SOS values are significantly lowered in patients with early RA and indicate that periarticular osteoporosis in early RA might possibly be better detected using detailed hand scan analyses.

Absorptiometry, Photon↗

PubMed2000

MR imaging of septic sacroiliitis.

OBJECTIVE: To investigate the diagnostic value of magnetic resonance (MR) imaging in detecting septic sacroiliitis and to determine whether the MR characteristics allow this entity to be differentiated from sacroiliitis in spondylarthropathy (SpA). PATIENTS AND DESIGN: The imaging findings of 11 patients with septic sacroiliitis were retrospectively analyzed by two experienced radiologists. Radiographic surveys of the pelvis as well as computed tomography (CT) and MR images of the sacroiliac joints were available in all cases. Seven of the patients additionally underwent a follow-up MR examination. The MR imaging protocol comprised combinations of coronal and transverse T1-weighted spin-echo (SE) or fast SE sequences, T2-weighted gradient-echo (GE) sequences and short tau inversion recovery sequence (STIR) sequences as well as dynamic contrast-enhanced T1-weighted acquisitions. RESULTS: Three patients with a short disease history showed anterior and/or posterior subperiosteal infiltrations ("lava cleft phenomenon"), transcapsular infiltrations of juxtaarticular muscle layers, which obscured the fasciae, and periarticular bone marrow edema. The eight patients with more advanced stages of sacroiliitis additionally showed abscess formation, sequestration, and erosion. At follow-up MR examination (n=7) under systemic antibiotic treatment, the morphologic characteristics showed progression (n=1), regression (n=4), unchanged findings (n=1), or a mixed response (n=1). Clinical improvement precedes resolution of the MR findings. CONCLUSIONS: Anterior and/or posterior subperiosteal infiltrations and transcapsular infiltrations of juxtaarticular muscle layers were depicted in all patients. These MR imaging findings are characteristic of septic sacroiliitis and may be used to differentiate this entity from sacroiliitis in SpA.

Adolescent↗

PubMed2000

[Inception cohorts for spondyloarthropathies].

The spondyloarthropathies (SpA) are important inflammatory rheumatic diseases--not only because patients of young age are frequently involved. Ankylosing spondylitis, reactive arthritis, and undifferentiated spondyloarthropathy are prototypes of SpA which share several clinical features and the strong association with HLA B27. Despite its high prevalence there are many shortcomings in early diagnosis and therapy of SpA. The same is true for the knowledge on course, prognostic factors, and the socioeconomic consequences of these diseases. Furthermore, our knowledge about pathogenesis and therapy is still limited. Due to the known deficiencies in rheumatologic education, there are clear-cut deficiencies in the health care provided by general practitioners. The aim of the project presented here is to built up a cohort of early SpA patients to learn about course and outcome of SpA. In this regard, special attention is paid to the inclusion of patients with juvenile SpA since AS starts frequently in the 2nd decade of life and because the clinical picture with more frequent peripheral joint involvement differs from AS of adult onset. Moreover, these cohorts play an essential role for other projects of the MedNet subdivision of infect-associated arthritides/spondyloarthropathies in which studies on diagnosis, therapy, immunology, and genetics of the SpA performed.

Adult↗

PubMed2000

[Severe precapillary pulmonary hypertension in possible antiphospholipid syndrome--partially successful long-term therapy with continuous intravenous iloprost administration. A case report with discussion of new treatment methods].

Undifferentiated connective tissue disease with secondary antiphospholipid syndrome was diagnosed in a 33 year old woman after recurrent arterial thromboses, two miscarriages and myocarditis. Despite effective immunosuppression and anticoagulation her initially mild precapillary pulmonary hypertension progressed in the absence of thromboembolic events, cardiopulmonary disease or other systemic disorders. With continuous i.v. iloprost in a dosage of up to 4.5 ng/kg/min for a total of 15 months, her 6 min walking-distance improved from 210 to 315 m, the pulmonary vascular resistance decreased from 1710 to 1111 dyn x s x cm-5 and the mean pulmonary arterial pressure decreased from 64 to 54 mmHg. This partial success of conservative treatment enabled a reassessment of the necessity for heart and lung transplantation.

Adult↗

PubMed2000

Imaging of sacroiliitis.

Inflammation of one or both sacroiliac joints is a characteristic feature of patients with spondyloarthropathies (SpA). Sacroiliitis often leads to inflammatory back pain (IBP). IBP and asymmetric peripheral arthritis of the lower limbs are the main clinical symptoms and criteria for classification and diagnosis of SpA in which sacroiliac joints are uni- or bilaterally affected with an intensity ranging from mild to very severe inflammation resulting in partial or complete ankylosis Sacroiliitis is a very frequent feature of undifferntiated SpA. In ankylosing spondylitis (AS) inflammation in the axial skeleton occurs rarely in the absence of sacroiliitis. Objective evidence of sacroiliitis obtained by imaging procedures, especially x-rays, has always been part of diagnostic and classification criteria for AS. This is in contrast to spinal radiography which, however, has been recently included in a core set of outcome items to be assessed in clinical studies. In early and acute stages of sacroiliitis the diagnosis can be difficult because conventional radiographs -- which are known to have considerable intra- and interobserver variability -- may be normal. Since IBP is not a specific indicator of sacroiliitis there is need for valuable imaging techniques. Scintigraphy lacks specificity. Computed tomography (CT) is a very good method to demonstrate already established bony changes and magnetic resonance imaging (MRI) has the advantage of combining a good visualisation of the complicated anatomy of the sacroiliac joint with the ability to localise different degrees of inflammation and oedema and prove a possible spread to muscles as it occurs in septic sacroiliitis, an important differential diagnosis.

Diagnosis, Differential↗

PubMed2000

Attentional effects on contrast detection in the presence of surround masks.

We studied how attention affects contrast detection performance when the target is surrounded by mask elements. In each display quadrant we presented a hexagon of six vertical Gabor patches (the 'surround'). Only one of the hexagons contained a central Gabor patch (the 'target') and the task was to report that quadrant (spatial four-alternative-forced choice). Attention was manipulated by means of a double-task paradigm: in one condition observers had to perform concurrently a central letter-discrimination task, and the contrast-detection task was then only poorly attended, while attention was fully available in the other condition. We find that under poorly attended conditions targets can be detected only when the target contrast exceeds the surround contrast (contrast popout) or when the target orientation differs from the surround orientation by more than 10-15 degrees (orientation popout). When the target orientation is similar to the surround orientation, attention can reduce the contrast detection thresholds in some cases more than four-fold, demonstrating a very strong attentional effect.

Attention↗

PubMed2000

Stentless bioprostheses have ideal haemodynamics, even in the small aortic root.

OBJECTIVE: To determine normal Doppler and 2D gradients and flow characteristics of the Freestyle stentless aortic bioprosthesis related to valve size. BACKGROUND: The Freestyle stentless aortic bioprosthesis is one of the newer aortic xenografts. Only limited data are available of the echocardiographic flow characteristics during a mid-term follow-up period of this valve. Therefore valve performance related to valve size was measured during a follow-up period of two years. METHODS: 175 consecutive patients with a Freestyle aortic bioprosthesis underwent an echocardiographic and Doppler examination according to a common protocol. Investigations were done within 4 weeks after operation, after 3 to 6 months, and after 1 and 2 years. RESULTS: With a valve size from 19 to 27 mm mean gradients decreased from 8.0 +/- 5.1 mmHg at discharge to 5.8 +/- 3.8 mmHg after 3-6 months (p < 0.001). Thereafter gradients remained stable. The performance index, the ratio of the measured effective orifice area in the patient divided by the effective orifice area measured in vitro increased from 69 +/- 20% at discharge to 79 +/- 29% after one, two and three years. Performance index was especially very high in the smaller sized valves with a performance index of 85 +/- 17% for the 21 mm valve. During follow-up mean gradients remained below 10 mmHg even in the 21 mm valve. CONCLUSION: Stentless xenografts have ideal haemodynamics, even in the small aortic root.

Animals↗

PubMed2000

HLA-DRB1*04 and susceptibility to type 1 diabetes mellitus in a German/Belgian family and German case-control study. The Belgian Diabetes Registry.

HLA-DR4 is a primary disease association marker in type 1 diabetes mellitus (IDDM). We therefore analyzed the transmission of 228 DR4+ haplotypes in 183 families with an IDDM proband (95 from Germany and 88 from Belgium). In a separate case-control data set, we investigated the HLA-DRB1*04 and DQ allele distribution in 245 IDDM patients and 177 controls from Germany, all DR4 positive. HLA-DRB1 *0401 and *0402 linked to DQB1 *0302 were significantly more often transmitted to patients in the studied families (81% and 89%) in contrast to DRB1 *0401-DQB1 *0301 (33%). The case-control study of HLA-DQB1 *0302+ individuals revealed -DRB1 *0405 to be more frequent in patients with IDDM and HLA-DRB1 *0403 and -DRB1 *0404 to be less frequent. HLA-DQA1 *0102-DQB1 *0602 and -DQA1 *0501-DQB1 *0301 in trans complementation with DRB1 *0401-DQB1 *0302 were also significantly less frequent in IDDM patients (P<3x 10(-7) and P<0.02). In conclusion, HLA-DRB1 *0403 and -DQB1*0301 alleles in cis as well as protective DQ haplotypes in trans, confer dominant protection against IDDM in a German / Belgian population.

Adolescent↗

PubMed2000

Targeting visual motion.

A new stimulus display reveals that humans summate the motion energies of all components consistent with a single velocity, rather than optimizing sensitivity by ignoring noise.

Data Display↗

PubMed2000

Neuronal activity in human primary visual cortex correlates with perception during binocular rivalry.

During binocular rivalry, two incompatible monocular images compete for perceptual dominance, with one pattern temporarily suppressed from conscious awareness. We measured fMRI signals in early visual cortex while subjects viewed rival dichoptic images of two different contrasts; the contrast difference served as a 'tag' for the neuronal representations of the two monocular images. Activity in primary visual cortex (V1) increased when subjects perceived the higher contrast pattern and decreased when subjects perceived the lower contrast pattern. These fluctuations in V1 activity during rivalry were about 55% as large as those evoked by alternately presenting the two monocular images without rivalry. The rivalry-related fluctuations in V1 activity were roughly equal to those observed in other visual areas (V2, V3, V3a and V4v). These results challenge the view that the neuronal mechanisms responsible for binocular rivalry occur primarily in later visual areas.

Algorithms↗

PubMed2000

Echocardiographic imaging of stentless aortic valve prostheses.

UNLABELLED: Homografts and stentless xenografts are increasingly used in aortic valve surgery. Echocardiography technicians and cardiologists have to know what they will find when performing an echo-Doppler examination in patients who received a stentless valve. We therefore evaluated echocardiographic images of 74 patients who received a Freestyle stentless bioprosthesis with three techniques and a follow-up of 2 years in two high-volume hospitals. Of the patients studied, 81% were operated using the subcoronary technique, 12% using the root-inclusion technique, and 7% using the full-root technique. RESULTS: Transvalvular gradients across the stentless valves were low: 8.0 mmHg when implanted with the subcoronary technique, 8.2 +/- 5.1 mmHg using the root-inclusion technique, and 6.5 mmHg using the full-root technique. Trivial aortic insufficiency (grade 1) was observed in 10.7% of the patients (8.9% for the subcoronary technique, 13% for the root-inclusion technique, and 0% for the full-root technique). When the bioprosthesis was implanted using the subcoronary technique or the root-inclusion technique, the prosthesis was placed inside the recipient aortic root. Using these techniques, a lumen between the double layer of the xenograft and the aortic wall could be observed. With the root-replacement technique, the porcine root became the most proximal part of the ascending aorta. As the native aortic wall was removed, in most cases, no double lumen could be observed with imaging of the ascending aorta.

Aortic Valve↗

PubMed2000

Identification of a novel bacterial sequence associated with Crohn's disease.

BACKGROUND & AIMS: Enteric microorganisms are implicated in the pathogenesis of Crohn's disease (CD), but no clear bacterial or viral species has been identified. In this study, representational difference analysis (RDA) was used to isolate DNA segments preferentially abundant in lamina propria mononuclear cells of lesional mucosa vs. adjacent uninvolved mucosa. METHODS: Two RDA-derived microbial sequences were isolated (I1 and I2) and identified as novel homologues of the ptxR and tetR bacterial transcription-factor families. RESULTS: Quantitative competitive polymerase chain reaction of paraffin-embedded intestinal specimens from 212 patients showed that I2 DNA was present in many CD colonic lesions (43%), but was infrequent in other colonic specimens (9% of ulcerative colitis lesions and 5% of non-inflammatory bowel disease diseases; P<0.0001). I2 was prevalent in ileal specimens, regardless of disease status (43%-54%). Enzyme-linked immunosorbent assay analysis of 150 individuals with an I2 glutathione-S-transferase fusion protein showed frequent immunoglobulin A seroreactivity in CD (54% of patients), but infrequent seroreactivity in patients with ulcerative colitis, other inflammatory enteric diseases, or normals (10%, 19%, and 4%, respectively; P<0.001 to 0.00001). CONCLUSIONS: These findings relate CD to a novel lesion-localized and immunologically associated bacterial sequence, suggesting that the microorganism expressing the I2 gene product may be related to CD pathogenesis.

Amino Acid Sequence↗

PubMed2000

Results of provider self-adjudication using the prudent layperson standard compared with the managed care organization's emergency department claim review process.

STUDY OBJECTIVES: We compare the results of a provider "self-adjudicating" outpatient emergency department claims using a "presenting symptom-based" system with the managed care organization (MCO) adjudicating the claims using a "final diagnosis-based" system. METHODS: All outpatient visits from one MCO to an urban, university hospital between January 1, 1998, and February 28, 1999, were included. Each record was reviewed by 2 methods to determine whether the visit qualified for payment under the MCO's benefit structure. Under the provider adjudication, symptom-based system, all visits with nursing triage levels of immediate/emergency were approved automatically. Those with triage levels of delayed/nonurgent were reviewed by an emergency physician and approved if, in the physician's opinion, the presenting symptoms met the emergency criteria under the District of Columbia's Access to Emergency Services Act. A second claims review, blinded to the first, was performed with the diagnosis-based system used by the MCO before approval of the prudent layperson standard. This review divided the records into "approve," "deny," and "suspend" categories according to the discharge International Classification of Diseases, ninth revision code. The results of the 2 reviews were compared. RESULTS: We reviewed 1,830 records; 836 (46%) cases were triaged as immediate/emergency and 994 (54%) as delayed/nonurgent. Of the 994 delayed/nonurgent visits, physician review determined that 607 (61%) met the prudent layperson standard and 387 (39%) did not. Overall, the provider self-adjudication system determined that 1,443 (78.8%) of the 1,830 visits should be approved for insurance coverage. The MCO's system approved 966 (53%), denied 335 (18%), and suspended 529 (29%). Provider self-adjudication using a symptom-based system resulted in the immediate approval of 1,443 (77.8%) visits compared with 966 (52.7%) by a diagnosis-based system (P <.001). Excluding the 529 suspended claims, McNemar's statistical testing of 1,302 records failed to demonstrate the equivalence of the 2 systems (P <. 001). CONCLUSION: Compared with the standard ED claims review process used by the managed care industry, provider self-adjudication using a symptom-based system approves a greater proportion of visits, avoids rejection of many ED visits, and identifies many nonemergency visits that mistakenly appear to be emergencies. The possibility of providers and MCOs working together to adjudicate outpatient ED claims should be explored.

Ambulatory Care↗

PubMed2000

Mapping the B cell superantigen binding site for HIV-1 gp120 on a V(H)3 Ig.

The emerging class of B cell superantigens includes HIV-1 gp120, which binds to many members of the V(H)3 Ig gene family. The present study addresses the structural features of V(H)3 antibodies conferring gp120 binding activity using a panel of recombinant full-length and Fab Ig proteins. Binding activity was fully conferred by the Fab portion of the Ig molecule. The V(H) region was the major determinant of binding; diverse light chains were permissive for gp120 binding. A series of recombinant V(H)3-V(H)1 chimeric molecules was created to analyze the contribution of different subregions of V(H)3 to gp120 binding. Hypervariable loop 1 (H1) substitution alone caused a 10-fold reduction in binding activity. The framework subregions (FR1, FR2 and FR3) and H2 also influenced binding, since substitutions of various combinations of these subregions conferred 10- to 100-fold binding reductions. We conclude that gp120 binding occurs through a non-conventional interaction involving multiple discontinuously arrayed residues spanning the V(H), and including roles in gp120 contact and favorable conformation of the V(H).

Amino Acid Sequence↗

PubMed2000

The possible role of myocardial biopsy in systemic sclerosis.

The histopathological features of heart involvement in systemic sclerosis (SSc) are not widely known. In internal and transplantation medicine, myocardial biopsies are increasingly used to diagnose cardiomyopathies including myocarditis. In two SSc patients presenting with dyspnoea with no evidence of pulmonary involvement, the cause of the compromised heart function was sought by myocardial biopsy. Immunohistological analysis revealed an increased number of CD3+ + T cells indicating myocarditis in one, and increased amounts of fibroblasts in both SSc patients. The authors think that myocardial involvement in SSc should be differentially evaluated and they propose the use of myocardial biopsies as a tool to distinguish between inflammatory and fibrotic forms of heart involvement in SSc patients.

Biopsy↗

PubMed2000

Heparin induces release of phospholipase A(2) into the splanchnic circulation.

UNLABELLED: Cardiopulmonary bypass results in increased plasma activity of phospholipase A(2) (PLA(2)) that appears to be caused by the administration of heparin. High PLA(2) activity may be responsible for increased production of eicosanoids and, thus, may be implicated in various pathophysiologic events associated with cardiac surgery. To investigate the site of PLA(2) secretion, blood samples were simultaneously collected from the radial artery, the pulmonary artery, and the hepatic vein at 2, 4, 6, and 20 min after systemic heparinization (350 U/kg). Within 2 min of the heparin injection, plasma activity of PLA(2) increased 4- to 9-fold and remained so for at least 20 min. Two minutes after the heparin injection, PLA(2) was significantly higher in the hepatic vein than in the radial artery (P: < 0.01). No such difference was detected between pulmonary and radial arteries. When heparin was added to blood samples in vitro (5-100 U/mL), plasma activity of PLA(2) did not increase, which suggests that the enzyme was not secreted by blood cells. IMPLICATIONS: Heparin, given in the dosage required for cardiopulmonary bypass, caused release of phospholipase A(2) into the splanchnic circulation.

Aged↗

PubMed2000

Defining new pathogens and nonculturable infectious agents associated with inflammatory bowel disease.

The causes of inflammatory bowel disease remain uncertain, but increasing evidence supports roles for two pathogenic processes: genetic susceptibility in the host and an aberrant host response to enteric bacteria. Here, we review studies showing that the pathogenesis of inflammatory bowel disease involves both bacterial agents and genetic susceptibilities. We discuss the roles of known and novel commensal intestinal bacteria in the pathogenesis of inflammatory bowel disease and the various recombinant approaches used to identify these pathogens.

Journal Article↗

PubMed2000

Colonic bacteria express an ulcerative colitis pANCA-related protein epitope.

Bacteria are a suspected pathogenic factor in inflammatory bowel disease, but the identity of the relevant microbial species remains unresolved. The pANCA autoantibody is associated with most cases of ulcerative colitis (UC) and hence reflects an immune response associated with the disease process. This study addresses the hypothesis that pANCA identifies an antigen(s) expressed by bacteria resident in the human colonic mucosa. Libraries of colonic bacteria were generated using aerobic and anaerobic microbiologic culture conditions, and bacterial pools and clonal isolates were evaluated for cross-reactive antigens by immunoblot analysis using the pANCA monoclonal antibody Fab 5-3. Two major species of proteins immunoreactive to pANCA monoclonal antibodies were detected in bacteria from the anaerobic libraries. Colony isolates of the expressing bacteria were identified as Bacteroides caccae and Escherichia coli. Isolation and partial sequencing of the B. caccae antigen identified a 100-kDa protein without database homologous sequences. The E. coli protein was biochemically and genetically identified as the outer membrane porin OmpC. Enzyme-linked immunosorbent assay with human sera demonstrated elevated immunoglobulin G anti-OmpC in UC patients compared to healthy controls. These findings demonstrate that a pANCA monoclonal antibody detects a recurrent protein epitope expressed by colonic bacteria and implicates colonic bacterial proteins as a target of the disease-associated immune response.

Amino Acid Sequence↗