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Biomedical subjects

J Braun

Publications and source records attributed to J Braun.

At least 397 records · Page 22Linked to original sources
PubMed1993

Selectivity for polar, hyperbolic, and Cartesian gratings in macaque visual cortex.

The neural basis of pattern recognition is a central problem in visual neuroscience. Responses of single cells were recorded in area V4 of macaque monkey to three classes of periodic stimuli that are based on spatial derivative operators: polar (concentric and radial), hyperbolic, and conventional sinusoidal (Cartesian) gratings. Of 118 cells tested, 16 percent responded significantly more to polar or hyperbolic (non-Cartesian) gratings than to Cartesian gratings and only 8 percent showed a significant preference for Cartesian gratings. Among cells selective for non-Cartesian gratings, those that preferred concentric gratings were most common. Cells selective for non-Cartesian gratings may constitute an important intermediate stage in pattern recognition and the representation of surface shape.

Animals↗
PubMed1993

[Radioimmunoscintimetry for intraoperative lymph node diagnosis in colorectal cancer].

In a prospective study 32 patients with primary colorectal carcinomas were studied by means of radioimmunoscintigraphy with the anti-carcinoembryonic antigen monoclonal antibody BW 431/26 labelled with either 131I (group 1, n = 17) or 99Tc (group 2, n = 15). Scintigraphy of the resected specimen was used as a model for intraoperative radioimmunoscintimetry, and all positive lymph nodes were marked during the investigation. The results were compared with the data yielded by preoperative investigations (CT, MR, endosonography) and checked by histology and immunohistochemistry. The analysis (sensitivity, specificity) included: type of investigation, time interval from antigen application, type of radionuclide, size of lymph nodes investigated, and serum level of CEA. 131I-Scintigraphy of the resected specimen gave the best results in the detection of lymph node metastases (sensitivity 1, specificity 0.57) and was superior to all other diagnostic procedures. When the investigation was performed 6-8 days after administration of the antibody the specificity improved to 1. The best results (sensitivity 1, specificity 0.91) were achieved in small (< 1 cm) lymph node metastases. A good correlation between scintigraphic diagnosis and immunohistochemical CEA detection was confirmed. Serum levels of CEA had no influence on the scintigraphic results. We conclude that intraoperative radioimmunodetection of lymph node metastases may improve the radicality in the resection of colorectal tumors. The best results are achieved with 131I-labelling and with application of the antibody 6-8 days before the operation.

Aged↗
PubMed1993

Widespread vasculopathy with hemolytic uremic syndrome, perimyocarditis and cystic pancreatitis in a young woman with mixed connective tissue disease. Case report and review of the literature.

A 15-year-old girl had severe Raynaud's phenomenon and arthralgias. A high ANA-IF titer was found and undifferentiated connective tissue disease was diagnosed. After 7 years of moderately flaring disease the patient deteriorated and presented with congestive heart failure, pleuropericardial effusion, hemolytic uremic syndrome, proteinuria and moderate hypertension. Autoantibodies against DNA, Sm-protein, and very high titers against U1RNP were detected. Therapy with high steroid doses, a cyclophosphamide pulse and 4 weeks of plasmaphresis with plasma exchange improved the heart, but not the renal condition. Symptomatic pancreatitis became the dominant problem of a progressively consuming process that resulted in the death of the patient. Post-mortem examination revealed widespread vasculopathy with intima proliferation and only minimal fibrosis involving the kidneys, heart and other main organs, including the pancreas. Taken together, the clinical picture was of an overlap between scleroderma and systemic lupus erythemathosus; the serologic and histopathologic findings suggest a diagnosis of a severe form of mixed connective tissue disease (MCTD).

Adolescent↗
PubMed1993

The value of specific antibody detection and culture in the diagnosis of reactive arthritis.

Joint inflammation, predominantly of the lower limbs, occurring some weeks after urogenital or gastrointestinal infection is classified as reactive arthritis (ReA) but there is no general agreement on diagnostic criteria, especially if the preceding infections are asymptomatic. The same is true for Lyme disease (LD) which is caused by Borrelia burgdorferi (BB). Determination of antibody titre or culture of urethral swabs and stools are often used as diagnostic tools. We examined 4 groups of patients: one with undifferentiated arthritis (Group I, n = 55), one with well-defined rheumatic diseases other than ReA (n = 43, Group II), one group without joint disease (n = 50, Group III) and one with ReA or LD (n = 7). Specific antibacterial antibody titres in serum were measured in all patients; stool and urethral cultures were performed in all groups except the last. A calculation of positive predictive value (PPV) was done for each test. Evidence of present or previous infection with the microbes Chlamydia trachomatis (CT), Mycoplasma urethritidis (MU), Yersinia enterocolitica (YE) and BB were found in all groups. In Group I, Group II and Group III respectively, positive serological results were found for CT IgA (20%, 31%, 16%) and IgG (49%, 51%, 34%), YE (7%, 6%, 0%) and BB (17%, 2%, 10%). Positive cultures were found in Group I and Group II respectively for CT (28%, 29%) and MU (14%, 17%). Therefore no test had a significant positive predictive value for ReA in the general population and even in the rheumatology clinic the PPV for most tests was low. We conclude that these methods are of little value in the diagnosis of reactive arthritis when the preceding infection is asymptomatic.

Adolescent↗
PubMed1993

In vitro maturation of equine oocytes collected by follicle aspiration and by the slicing of ovaries.

The aim of this study was to examine 2 techniques for oocyte recovery from equine ovaries at slaughter: by aspiration of follicles and by additional slicing of ovaries. The morphology and nuclear configuration of oocytes recovered with either technique, and the time course of nuclear maturation during in vitro maturation were evaluated. Recovery rates were 1.75 and 4.14 oocytes per ovary for aspiration and slicing (total 145 and 344 oocytes from 83 ovaries), respectively. The oocytes were classified according to their cumulus/ooplasm morphology into 4 groups: compact/circular(A), compact/semicircular(B), expanded(C) and others(D). The percentages of oocytes in Groups A, B, C and D were 34, 38, 25 and 3% (aspiration) and 55, 26, 17 and 3% (slicing), respectively. The proportions of oocytes with a germinal vesicle in Groups A, B, C and D were 28 29 (97%), 23 35 (66%), 11 23 (48%) and 2 4 (50%) in oocytes from aspiration and 91 100 (91%), 52 65 (80%), 15 29 (52%) and 1 2 (50%) in oocytes from slicing, respectively. Group A and B oocytes recovered by aspiration (n=212) and slicing (n=312) were cultured in TCM199 supplemented with 10% fetal bovine serum, 1 mug/ml estradiol-17beta, and 0.02 AU/ml FSH at 38.5 degrees C in 5% CO(2) in air (5 to 10 oocytes per 50- mu l microdrop). At 8, 16, 24, 32 and 40 h of culture, the oocytes were fixed and stained. There were no significant differences in the percentages of Metaphase II stage (MII)-oocytes between recovery techniques at any time points examined. The proportions of MII-oocytes were 1 42 (2%), 4 43 (9%), 21 42 (50%), 28 45 (62%), and 28 40 (70%) at the respective time point in oocytes from aspiration and 0 51 (0%), 3 54 (6%), 22 59 (37%), 43 72 (60%), and 51 76 (67%) in oocytes from slicing, respectively. In most of the oocytes, resumption of meiosis occurred between 8 and 16 h of culture. The proportions of MII-oocytes increased significantly between 16 and 24 h and between 24 and 32 h of culture.

Journal Article↗
PubMed1993

The possible role of Shigella in sporadic enteric reactive arthritis.

Reactive arthritis (ReA) occurs after a urogenital infection usually with Chlamydia trachomatis or an enteritis due to Yersinia, Salmonella, Campylobacter or Shigella, Shigella, except during epidemics, is not considered to be a frequent cause of enteric reactive arthritis. However this might be due to the lack of a reliable antibody test, which makes diagnosis difficult. We compared synovial and peripheral blood lymphocyte proliferation to various bacterial antigens in 19 consecutive patients with ReA or undifferentiated oligoarthritis. In five patients Shigella was identified as the causative microbe by a specific synovial lymphocyte proliferation. All five patients had a history of symptomatic diarrhoea and had negative stool cultures by the time arthritis developed. Four of the five were HLA B27 positive. We conclude that Shigella may be underestimated as a cause of non-epidemic ReA.

Adult↗
PubMed1993

Evaluation of maxillofacial vascular abnormalities with Tc-99m RBC.

Three-phase scintigraphy using Tc-99m RBC was performed in seven patients with vascular abnormalities of the maxillofacial region. Scintigraphy was able to distinguish whether the lesions had increased perfusion (three patients) or only a large venous component (four patients), and thus helped in assessing the best route for contrast angiography. In four patients a recurrence was suspected. In one, a follow-up Tc-99m RBC study showed successful embolization therapy and no recurrence, and in three patients it showed early recurrence of the lesion. The results of this report indicate the value of Tc-99m RBC scintigraphy in the management of patients with vascular abnormalities of the maxillofacial region.

Adult↗
PubMed1993

T cells are responsible for the enhanced synovial cellular immune response to triggering antigen in reactive arthritis.

In reactive arthritis (ReA) there is specific proliferation of synovial fluid (SF) mononuclear cells (MNC) to the triggering bacterial antigen; comparatively little or no response is seen in peripheral blood (PB). To investigate the mechanism of this elevated local immune response, we examined patients with typical ReA who showed an enhanced antigen-specific synovial immune response in bulk culture. Using separated fractions of T cells and antigen-presenting cells (APC) from PB and SF we showed that the synovial T cells rather than SF APC are responsible for the specific proliferation. By limiting dilution analysis, the frequency of T cells responding to the specific antigen was found to be significantly increased compared with the frequency of irrelevant antigen-specific T cells. Furthermore, the frequency of T cells responding to the specific antigen was higher in SF (between 1/619 and 1/4846, mean 1/2389) than in PB (between 1/1286 and 1/16,279, mean 1/7350). We conclude that the specific synovial cellular immune response in ReA is mainly due to an expansion of antigen-specific T cells within the joint. However, the non-specific hyper-reactivity of SF T cells and differences between SF and PB APC may make a more minor contribution.

Adult↗
PubMed1993

Analysis of cytokine profiles in synovial T cell clones from chlamydial reactive arthritis patients: predominance of the Th1 subset.

Subpopulations of human T cells (Th0, Th1 and Th2) can be distinguished by their cytokine-secretion pattern. Evidence is increasing from other studies that the outcome of a human disease may depend on the subpopulation of T cells that predominates at the site of inflammation. Reactive arthritis serves as a useful model of chronic inflammatory diseases, because the triggering antigen can be identified. Using this triggering antigen we raised 33 T cell clones reactive with Chlamydia trachomatis and 25 T cell clones that were not reactive, all from the synovial fluid of two patients suffering from Chlamydia-induced arthritis. Their cytokine secretion patterns for interferon-gamma (IFN-gamma), IL-2 and IL-4 were analysed, as also were mRNAs for IFN-gamma and IL-10 by in situ hybridization. Out of the 33 antigen-reactive clones 23 showed a Th1 pattern with IFN-gamma but not IL-4 secretion, while the remaining 10 exhibited a Th0 pattern. The clones that did not react with Chlamydia expressed all patterns of cytokine secretion, including a Th2 pattern, thus providing a control population that excludes bias in the sampling procedure. CD4 and CD8 clones displayed a similar cytokine-secretion pattern. In addition this study demonstrates for the first time the expression of IL-10 mRNA in T cell clones derived from synovial fluid, and this was not confined to the Th2 subset. The Th1 response that Chlamydia provoke can be regarded as appropriate for such an obligate intracellular pathogen.

Adult↗
PubMed1993

Intercellular adhesion molecule 1 (ICAM-1) in the pathogenesis of mononuclear cell alveolitis in pulmonary sarcoidosis.

BACKGROUND: Alveolitis in pulmonary sarcoidosis is characterised by an accumulation of highly activated macrophages and CD4+ lymphocytes in the alveolar compartment. The role of intercellular adhesion molecule 1 (ICAM-1) expression on alveolar cells has been studied in this context. METHODS: Using a sandwich ELISA technique, ICAM-1 expression on alveolar macrophages from 17 consecutive untreated patients with pulmonary sarcoidosis and six healthy normal volunteers was quantified. In addition, parameters of macrophage activation (tumour necrosis factor alpha (TNF alpha) and superoxide anion release) were evaluated. RESULTS: Significantly elevated expression could be demonstrated on alveolar macrophages from patients with pulmonary sarcoidosis compared with healthy controls (mean (SD) 0.74 (0.24) ELISA units (EU) v 0.46 (0.12) EU). On subdividing the patients into those with active and those with inactive disease, only the former showed increased ICAM-1 levels on alveolar macrophages (0.82 (0.27) EU) compared with control alveolar macrophages. No differences were detected in serum levels of soluble ICAM-1 between patients and controls. ICAM-1 expression on alveolar macrophages from patients with sarcoidosis correlated with the spontaneous release of TNF alpha but not with the release of the superoxide anion by the activated macrophages. There was no correlation with the percentage of lymphocytes or the absolute number of CD4+ cells in bronchoalveolar lavage fluid. CONCLUSIONS: Increased ICAM-1 surface expression on alveolar macrophages reflects disease activity in the pulmonary compartment. Considering the significance of adhesion molecules during antigen presentation and lymphocyte activation, ICAM-1 expression on alveolar macrophages may have an important role in the immune process of pulmonary sarcoidosis.

Adult↗
PubMed1993

Shape-from-shading is independent of visual attention and may be a 'texton'.

Shading was used to generate the appearance of an obliquely illuminated surface with spherical indentations and protrusions. The "pop-out" of an apparent indentation among numerous apparent protrusions served as a psychophysical assay for shape-from-shading. Detectability of the pop-out varied with the direction of apparent illumination, a finding which is characteristic for shape-from-shading and which demonstrated the appropriateness of this assay. Observers were able to concurrently detect two shape-from-shading pop-outs in different parts of the display, demonstrating that shape-from-shading is a parallel process. In another experiment, visual attention was engaged by a letter discrimination task. Nevertheless, observers were able to detect a shape-from-shading pop-out concurrently in the unattended part of the display, suggesting that shape-from-shading is independent of visual attention. Thus, shape-from-shading shares some of the characteristics of Julesz' textural stimulus dimensions ('textons').

Attention↗
PubMed1993

Long-term administration of 13-cis retinoic acid in common variable immunodeficiency: circulating interleukin-6 levels, B-cell surface molecule display, and in vitro and in vivo B-cell antibody production.

We have previously shown that retinoids can induce differentiation of B cells in vitro as well as in vivo in patients with common variable immunodeficiency (CVI). While changes were observed over 1 week when retinoic acid (RA) was added to CVI hybridoma cells in vitro, maturation of the patients' B-cell compartment in vivo occurred only after 4 months of drug administration. We have now performed a 64-week open trial of oral 13-cis RA in five patients to see if prolonged treatment would result in continued improvement in their humoral immune compartment. In this trial, drug was given for 32 weeks followed by a 32-week wash-out period. During the treatment, the patients showed changes in a variety of parameters indicating an alteration towards normal of their humoral immune systems. This change included a fall in the elevated circulating interleukin-6 (IL-6) levels, a more normal display of B-cell surface markers (L-selectin and CD20), a decrease in B-cell size, and improved in vitro and in vivo B-cell function. In order to determine if VH gene use was affected by the retinoid treatment, VH gene expression in the CVI patients was characterized. Results showed an unusual predominance of non-mutated VH gene sequences, representative of cells that are recent bone marrow emigrants. While no common pattern of change occurred in VH gene segment use in the patients while on retinoid therapy, large-scale (> 10-fold) changes in the expression of these genes were observed in each individual over time. Taken together, these results provide multiple lines of evidence that 13-cis RA promotes maturation of B cells in patients with CVI. However, the effect appears to be partial, such that stimuli in addition to 13-cis RA will be necessary to provide for further B-cell differentiation in order to achieve normalization of humoral immunity.

Adolescent↗
PubMed1993

Quantitative analysis of anti-CEA antibody accumulation in human colorectal carcinomas.

In order to obtain quantitative data on intratumoral antibody accumulation we analyzed resected colorectal adenocarcinomas of 25 patients who had undergone immunoscintigraphy 4-14 days earlier. All had been injected with 0.5-1.0 mg intact anti-CEA antibody (BW 431/26) labelled with 70-80 MBq131I. Correlation of tissue radioactivity concentrations with tumor characteristics revealed significantly higher values in necrotic compared to viable as well as in CEA-positive compared to CEA-negative viable tumor tissue indicating action of both specific and unspecific uptake mechanisms. In contrast, diagnostic results of immunoscintigraphy were influenced by tumor size only. 11 of 12 false-negative findings were obtained in tumors < 4 cm in diameter. Since ex-vivo scintigraphy of resected specimens correctly visualized all but one of these lesions, it is concluded that technical limitations of scintigraphy are the main cause of negative results of radioimmunoimaging with 131I-labelled antibodies.

Adenocarcinoma↗