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Biomedical subjects

S Prange

Publications and source records attributed to S Prange.

9 recordsLinked to original sources
PubMed2001

Transplanted MHC class I-deficient nonobese diabetic mouse islets are protected from autoimmune injury in diabetic nonobese recipients.

The injury of transplanted islets may occur by both autoimmune and alloimmune processes directed against MHC targets. To examine the role of MHC class I in islet graft injury, we transplanted syngeneic and allogeneic beta2-microglobulin-deficient islets into diabetic nonobese diabetic (NOD) mice. Loss of graft function was observed within 14 days using allogeneic C57BL/6 and BALB/c MHC class I deficient as well as wild-type MHC class I-bearing NOD donor islets. However, islets isolated from MHC class I-deficient NOD mice (NOD-B2 m-/-) survived indefinitely when transplanted under the kidney capsule of diabetic NOD recipients. Transplanted NOD-B2 m-/- islets were surrounded by a nondestructive periinsular infiltrate that expressed interleukin-4 in addition to interferon-gamma. These studies demonstrate the primary role of MHC class I molecules in causing autoimmune destruction or recurrent diabetes in transplanted islets.

Animals↗
PubMed2000

Ultrasonic sensor properties characterized by a PC-controlled scanning measuring system

The use of ultrasonic sensors for process control is currently widespread for flow, level or distance measurements. Recently, interest has increased, too in the application of ultrasonic sensors to concentration measurements in complex liquids. In this application there are high demands for a defined and stable quality of the properties of both the sensor transfer function and the sound field characteristic. For a detailed investigation and characterization of ultrasonic sensor propertiess, an efficient PC-controlled measuring system was developed by the Institut fur Automation und Kommunikation (IFAK). In this contribution, this high performance approach is presented to make visible the vibrating ultrasonic sensor surface as well as the sound field in front of acoustic sensors in liquids.

Journal Article↗
PubMed2000

In-line concentration measurement in complex liquids using ultrasonic sensors

Recently there has been increased demand for chemical sensors measuring in-line the concentration of selected substances in complex liquids in order to guarantee a high product quality in the process industry. At present there is a great interest in acoustic sensor systems for concentration measurements. This article presents a new ultrasonic sensor system consisting of a miniaturized multi-sensor arrangement for the comprehensive acoustic characterization of liquid mixtures. The sensor system measures sound velocity, impedance coefficient, attenuation coefficient and temperature.

Journal Article↗
PubMed2000

[Measurement of spinal anteflexion in school children by ultrasound topometry].

AIM: The anteflexion of the spine in normal schoolchildren was examined by 3D real-time ultrasound topometry to see if differences in the form of restrictions of anteflexion could be detected. METHODS: 102 schoolchildren at the age of 7 to 9 years volunteered to the study. We measured the spinal anteflexion by recording the row of the spines (C7-L5) in a maximally flexed position with a topometric digitiser. By computer-aided data analysis the curvature of the spinal line was reproduced by lined up radii. RESULTS: In the sagittal plane the spinal line in anteflexed position showed a single curvature in 8 cases. In 94 cases the spinal line was subdivided into three curvatures (X1, X2, X3) with less mobility of the region from the middle to the lower thoracic segments. For these less mobile segments we calculated a mean relative anteflexion (X2/[(X1 + X3)/2]) of 0.36 (+/- 0.18). In seven children (6.8%) with clinically indirect signs of scoliosis the anteflexion was reduced and in 4 cases out of the standard deviation. For the relative anteflexion the Pearson's correlation coefficient of the measurement 1 and the direct control-measurement was 0.86 (p < 0.001). CONCLUSION: By ultrasound topometric measurement of the spinal anteflexion in schoolchildren we are able to identify cases with less ability of anteflexion. Because a restriction of anteflexion is discussed in the pathogenesis of idiopathic scoliosis, a follow up of these children seems to be usefully.

Biomechanical Phenomena↗
PubMed1999

Evaluation of chronic tears of the rotator cuff by ultrasound. A new index.

The diagnosis of chronic lesions of the rotator cuff is challenging. We have developed a new index to improve the sonographic diagnosis of chronic tears of the cuff. In a pilot study, we examined 50 asymptomatic healthy volunteers by ultrasound to establish the diameter of the rotator cuff in relation to the tendon of the long head of biceps. Subsequently, the index was calculated in 64 patients who had had shoulder pain for more than three months caused by clinically diagnosed lesions of the rotator cuff. The compensatory hypertrophy of the biceps tendon was quantified sonographically in relation to the diameter of the cuff. Comparison with the contralateral shoulder revealed a significantly higher biceps rotator-cuff ratio (p < 0.05) for patients with torn rotator cuffs. A ratio greater than 0.8 was considered pathological (index positive); the mean ratio in the control group was 0.43. The sensitivity of a positive index was 97.8%, the specificity 63.2%, the positive predictive value 86.3%, and the negative predictive value 92.4% in comparison with surgical findings. Use of the index improves sensitivity in the diagnosis of chronic tears of the cuff by ultrasound.

Adult↗
PubMed1998

Protective and destructive effects of microbial infection in insulin-dependent diabetes mellitus.

Insulin-dependent diabetes mellitus (IDDM) is a T-cell mediated autoimmune disease, which results in the destruction of the islet beta-cells. The major histocompatibility complex (MHC) encodes the major susceptibility gene in IDDM. The concordance rate for diabetes in identical twins is 30-50% and in inbred animal models of disease the incidence rate is 20-80%. These results emphasize a role for environmental factors in the disease process. It has long been suggested that IDDM in humans may be caused by-viral infections. While considerable progress has been made in defining the genetics of IDDM, our understanding of the role of environmental factors, which might provide a more direct approach to therapy is considerably lacking. We suggest that (1) the density and affinity of epitopes derived from microbial antigens that bind to MHC molecules; (2) their cross-reactivity with beta-cell antigens; and (3) the nature of immunoregulatory cytokines induced by the microbial infections are the primary factors in the induction of either effector or protective T cells in IDDM.

Animals↗
PubMed1997

Modulation and detection of IDDM by membrane associated antigens from the islet beta cell line NIT-1.

We have utilized the NOD islet beta-cell line NIT-1 to monitor beta-cell specific autoantibodies and to investigate the modulation of IDDM in NOD mice by NIT-1 membrane associated antigens. The sera from diabetic but not from pre-diabetic or protected NOD mice strongly stained NIT-1 cells in FACS analysis. The cell surface antigens on NIT-1 cells were trypsin-sensitive. NIT-1 cells could not be stained by anti-mouse GAD67 antibody; however, we could demonstrate the presence of GAD65 and GAD67 mRNA by RT-PCR. Longitudinal analysis of anti-NIT-1 antibodies showed that these antibodies were present in the neonates but disappeared after weaning. Sonicated NIT-1 cell membrane preparations protected NOD mice from diabetes when injected intravenously in 5 week old mice. The protection was associated with reduced cytotoxic activity and elevated Th2-like responses as indicated by IgG1 antibodies against the NIT-1 cells. Subcutaneous injection of sonicated NIT-1 membranes or the injection of control red blood cell membranes failed to induce protection. We conclude that NIT-1 cell membranes do not express GAD but contain other antigens that are important in the development and prevention of IDDM. These antigens could be useful for the diagnosis of diabetes by monitoring autoantibody levels and for the modulation of IDDM by immunotherapy.

Animals↗
PubMedDate not supplied

[Ultrasound topometric measurements of thoracic kyphosis and lumbar lordosis in school children with normal and insufficient posture].

AIM: The posture of school children was examined in order to establish whether possible differences in clinically normal and insufficient posture can be detected by means of ultrasound topometry. METHOD: 105 healthy school children (56 female, 49 male) with an average age of 8 years (+/- 0.9) were examined. To classify the children as having sufficient or insufficient posture the Matthiass posture test was used. While the child stood in a relaxed position, the profile of the spine was measured with a topometric digitiser, recording each spinal processus from C7 to L5. RESULTS: 42 children (22 female, 20 male) showed an insufficient posture during the Matthiass test. The topometrically measured angles of kyphosis and lordosis were significantly smaller in these children, corresponding to a clinically greater thoracic kyphosis and lumbar lordosis. No significant differences in the lateral and anterior-posterior trunk deviation, nor in the range of trunk sway in the relaxed standing position could be observed. CONCLUSION: Using ultrasound topometry, the posture of children with sufficient and insufficient posture can be differentiated by measuring, the angles of kyphosis and lordosis. This quantification could be used for objective monitoring of the posture.

Anthropometry↗