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Biomedical subjects

M Reiser

Publications and source records attributed to M Reiser.

At least 541 records · Page 30Linked to original sources
PubMed1991

Transition from self tilt to object tilt during maintained lateral tilt in parabolic flight.

19 young healthy subjects were subjected to parabolic rollercoaster flight. A horizontal luminous line was seen by the subjects in a headfixed goggle device. During the hypergravic phases of parabolic flight the luminous line seemed to rotate into and during the hypogravic phase against the direction of static head tilt. Ocular counter rotation and activity of the neck position receptors cannot explain these subjective rotations. We conclude that information from the otolith system, converging with visual information within the brain, dislocated the headfixed visual target line. While the retinal image of the luminous line remains unchanged, loading and unloading the otoliths in parabolic flight changes the sensation of self tilt into object tilt, hereby subjectively rotating visual targets such as the luminous line.

Eye Movements↗
PubMed1991

[The radiological image of pleural lipomas with special reference to computed tomography].

Diagnostic assessment of focal pleural mass requires CT examination, particularly in follow-up of anamnestic tumour conditions. Since 1976 well-delineated pleural masses that were suspicious for malignancy on chest films, were identified in 11 patients as lipomas, using CT. They showed semicircular, oval or polygonal shape, but no really "spheric" aspect on biplane chest films. Main diameters of these masses were 2.5 to 6 cm and only once 11 cm. Density values mostly ranged from -110 to -70 HE (min. -133, max. -22 HE) in nonenhanced CT studies. Findings were localised adjacent to the parietal pleura seven times (in one patient two separate findings) and to the diaphragmatic pleura five times. In 7751 CT examinations of the chest, the incidence of pleural lipomas was 0.14%, their prevalence concerning solid pleural lesions being 5.3%. Among all intrathoracic lipomas those in mediastinal and paracardial location respectively were definitely more often (30 patients).

Aged↗
PubMed1991

Detection of hepatic masses in patients with carcinoma: comparative sensitivities of sonography, CT, and MR imaging.

To evaluate the sensitivity of sonography, CT, and MR imaging in the detection of hepatic masses in carcinoma patients, we conducted a prospective study of 75 consecutive patients with gastrointestinal tumors who were admitted for surgical resection of the primary tumor. Sonography was performed with convex transducers of 3.5 and 5.0 MHz. Three noninvasive CT techniques were used: unenhanced CT scans, the incremental bolus dynamic scanning technique, and delayed scanning 4-6 hr after bolus injection of 60 g of iodine. MR images (1.5 T) were acquired as presaturated T1- and T2-weighted spin-echo sequences and as breath-holding fast low-angle shot (FLASH) 60 degrees and FLASH 15 degrees sequences. As it is difficult to distinguish benign from malignant masses solely on the basis of morphologic criteria, the techniques for each imaging method were designed to detect and not to characterize hepatic lesions. Each examination was interpreted blindly, and the results were compared with surgical findings, intraoperative sonography, and biopsy of the liver as the gold standard. All focal hepatic masses verified at surgery, malignant or benign, were included in the analysis. Sixty-five (68%) of 95 focal hepatic masses were detected by CT, 60 lesions (63%) by MR, and 50 lesions (53%) by sonography. Although lesions 1-2 cm were shown almost equally well by CT and MR (74% and 77%, respectively), the detection rate of smaller lesions (less than 1.0 cm) decreased more drastically with MR (31%) than with CT (49%). Sonography had a sensitivity of only 20% with the smaller lesions. All imaging techniques had a sensitivity of 100% for focal hepatic masses larger than 2.0 cm. Our results show that CT has a higher overall sensitivity (68%) than MR and sonography for the detection of focal hepatic masses. When the results of the three procedures are combined, the overall sensitivity is 77%. This is unsatisfactorily low, as CT and MR have a size threshold of about 1.0 cm and are relatively unreliable for the detection of smaller lesions.

Adenocarcinoma↗
PubMed1991

Parabolic flight as a tool to measure ocular counterrotation in a reduced force environment.

Five unmedicated subjects were flown in parabolic flight. The aircraft, a Caravelle, performed single parabolae every 2 to four minutes. This resulted in alternating phases of normal, hyper-, hypo- and again hyper-gravity. Subjects sat yoga fashion upright facing towards the aircraft cockpit. Head and/or trunk were deflected 30 degrees from the upright, stimulating otolith and/or neck receptors. During each pullup, low-g phase and pullout of the parabolae a picture of the left eye was recorded on video tape. On the ground ocular roll (OCR) was determined from these video recordings. OCR ranged from 0.9 to 6.9 degrees in l-g and from 1 to 7.2 degrees under high-g, depending on head and trunk position. Neck receptor contribution was found to induce OCR of 0.2 degree to 2.1 degrees in two subjects.

Adult↗
PubMed1991

Subjective luminous line perception under changing g-load and body-positions in parabolic flight.

Five healthy subjects were subjected to parabolic flight with laterally tilted head, trunk, or body position. A vertical luminous line was viewed by the subjects in a head-fixed goggle device. During normal, hyper- and hypogravity phases subjective luminous line orientation was measured. The data imply that stimulation of the neck position receptors markedly influences the perception of the subjective vertical as well as mechanisms of convergence of otolithic signals and visual information within the brain.

Adult↗
PubMed1991

[Comparative evaluation of 3 leukocyte filters for thrombocyte concentrates].

Several polyester adsorption filters are available for the removal of leukocytes during bedside filtration of platelet concentrates (PC). We tried to evaluate the efficacy of three leukocyte filters: PL-100 (Pall, USA), Sepacell PL-5A and PL-10A (both Asahi, Japan) using single donor PCs. All filters were used according to the manufacturer's instructions. The main difference in handling is the recommendation of priming and rinsing the Asahi filters with saline. Platelet counts were performed by an automatic cell counter, leukocyte (WBC) counts using a modified chamber method. Biocompatibility was examined by assessing anaphylatoxin, PMN-elastase and LDH levels, platelet function by measuring induced aggregation, hypotonic shock response, beta-thromboglobulin levels and the mean platelet volume. According to the different initial WBC contamination, three groups of PCs were tested. Group I and II were processed one hour after apheresis. Group III (n = 30) was stored at 12 degrees C up to five days before filtration. Function and integrity of post-filtration platelets were not affected as compared to the prefiltration status and bioincompatibility could not be detected. Our results indicate that the WBC reduction capacity of the filters is related to the initial WBC contamination of the PC. Beyond an initial contamination of 10(9) WBC, none of the filters is capable of reducing the leukocyte count below 10(6) WBC/PC. All but PL-5A reduce the WBC reliably below 10(6)/PC as determined from PCs routinely prepared. The Asahi filters cause significantly less platelet loss apparently due to the suggested postfiltration rinsing. Storage of PC does not influence the WBC reduction capacity, however increases the platelet loss for the PL-100.

Blood Component Transfusion↗
PubMed1990

[The visualization of metal implants with digital luminescence radiography].

DLR makes it possible to integrate conventional radiography into digital communication and storage methods (PACS) into radiology. The use of DLR has been compared with conventional film methods in the demonstration of hip prostheses. The high contrast differences at the edge of the metal implant leads to artifacts, which could result in erroneous interpretation. Suitable image manipulation makes it possible, however, to eliminate these artifacts almost completely. DLR leads to an improvement in diagnosis in those complications not specifically related to the prostheses.

Evaluation Studies as Topic↗
PubMed1990

[Malignant skin and soft tissue tumors--diagnostic imaging].

Clinical evaluation of the definite size and extension of malignant skin- and soft tissue tumors is limited. Ultrasound provides a first orientation of tumor size and differentiates between solid and cystic lesions. Conventional Radiographs prove or rule out bone or periostial involvement and endotumoral calcification. If further diagnostic workup is needed MRI is the method of choice for defining the exact tumor topography, size and the affected compartments as well as the involvement of cancellous bone and bone marrow.

Diagnostic Imaging↗
PubMed1990

[Tuberculous spondylitis following BCG vaccination].

A case of a rare form of BCG osteomyelitis in the spine is presented. After vaccination, the disease started with a lymphadenitis. Later an abscess extended from the pelvic along the psoas muscles into the retroperitoneum. The soft tissue mass extended paraspinally and epidural involvement was also apparent. The vertebral involvement was detected by CT. The radiological findings are discussed with reference to the literature.

BCG Vaccine↗
PubMed1989

Two-stage therapy in the treatment of sacral tumors.

Sacral tumors are rare and may be clinically overlooked for a long period, because the symptoms and signs are often mild and non-specific. This led to frequent errors in clinical diagnosis and a long delay between the onset of symptoms and treatment. On presentation the lesions frequently expanded the anterior cortex, however, in most patients the periosteum of the sacrum and the presacral fascia form an unbroken barrier for a tumor. The pelvic viscera are not infiltrated by the tumor until late. Wide excision is difficult and often causes urogenital and/or anorectal dysfunction, but preserving the sacral nerve roots often leads to local recurrence. Surgical wide excision with a combined anterior-posterior approach is considered the treatment of choice for large lesions with significant anterior intrapelvic extension. This paper reports data resulting from the treatment of five large sacral tumors with comments on the results.

Adult↗
PubMed1989

[The x-ray morphology of chondromyxoid fibroma].

29 cases of chondromyxoid fibroma (CMF) from the material submitted to the Bone Tumour Register in Münster were reviewed. The tumour was observed most frequently in the second and third decades of life, with a slight female preponderance in our series. The diaphyseal and metaphyseal regions of the lower limb were most commonly affected, with a particular predisposition for the knee. The lesions were located eccentrically in 71% showed cortical expansion in 72%, and pseudotrabeculation in 51% of cases. The lytic patterns were classified as Lodwick IA in 35%, as Lodwick IB in 45%, as Lodwick IC in 17% and as Lodwick II in 3% of cases. Due to the absence of characteristic radiographic features, the differential diagnosis from aneurysmal bone cyst, giant cell tumours and non-ossifying fibroma is often difficult. Radiographic findings would however indicate benignity and, therefore, help to differentiate the lesion from chondrosarcoma, to which it bears strong histological similarity.

Adolescent↗