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Biomedical subjects

G Hermann

Publications and source records attributed to G Hermann.

At least 145 records · Page 8Linked to original sources
PubMed1986

Computed tomography and ultrasonography of the hemophilic pseudotumor and their use in surgical planning.

Twenty-one hemophilic pseudotumors in 17 patients were evaluated radiologically to facilitate surgical planning. Plain radiography, angiography, intravenous urography, computerized tomography (CT), and ultrasonography (U/S) were the modalities used. CT proved to be the most efficient method in the detection of bone destruction and soft tissue lesions including additional daughter cysts. The combination of CT, intravenous urography, and angiography were used in pelvic pseudotumors, and that of CT and angiography for extremity pseudotumors, to determine the proper surgical approaches to the lesions. As a non-ionizing technique, U/S was usually preferable in visualizing soft tissue masses and, in sequential studies, to evaluate progress or recurrence of the lesion.

Adult↗
PubMed1986

Effects of previous myocardial infarction on measurements of reactive hyperemia and the coronary vascular reserve.

The measurement of coronary vascular reserve by the reactive hyperemic response to ischemia has been advocated as a practical method of assessing the physiologic significance of coronary stenoses. Because the concept of measuring coronary blood flow during maximal vasodilation assumes a normal arteriolar network and viable myocardium, the presence of previous myocardial infarction may cause a significant decrease in the coronary reserve unrelated to the severity of a coronary stenosis itself. To determine the potential importance of this effect, rest and hyperemic coronary blood flow were measured in 14 dogs in the regions subtended by the left anterior descending and left circumflex coronary arteries. One hour occlusion of the left anterior descending artery followed by reperfusion was performed in 10 dogs; the 4 remaining dogs in which no occlusion was performed served as control animals (group 3). One week later, rest and hyperemic blood flow measurements were repeated in all 14 dogs. Of the 10 dogs undergoing left anterior descending artery occlusion, 5 had a large infarct (group 1) and 5 had a small infarct (group 2). In group 1 in the 1 week study, both the coronary reserve in the left anterior descending artery zone and the ratio of the coronary reserve in this zone and the left circumflex artery zone decreased compared with values before occlusion (from 425 +/- 134 to 150 +/- 34% and from 1.56 +/- 0.40 to 0.68 +/- 0.31, respectively; both p = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Gaucher's disease type 1: assessment of bone involvement by CT and scintigraphy.

The effectiveness of CT and technetium-99m sulfur colloid (99mTc SC) bone-marrow scans in determining the extent and severity of skeletal involvement in 23 patients with type 1 Gaucher's disease was compared with the effectiveness of conventional radiographic techniques and technetium-99m methylene diphosphonate (99mTc MDP) bone scintigrams. Density measurements obtained by CT proved sensitive in differentiating normal marrow (-50 to -120 H). Scintigrams with the sulfur colloid nuclide demonstrated three distinct patterns of uptake: peripheral expansion of normal marrow (profile B), greater marrow expansion with patchy areas lacking uptake (profile C), and greater loss of uptake with retention of the nuclide in other reticuloendothelial organs and circulation (profile D). CT scans provided greater sensitivity in resolving the extent of marrow involvement in affected areas, while the 99mTc SC scintigrams were more effective in overall assessment of the severity of bone-marrow involvement. Both conventional radiographic techniques and 99mTc MDP bone scans were useful primarily as screening procedures or for evaluating specific involved areas. 99mTc MDP scans were useful in evaluating regional defects (i.e., ischemic necrosis) in certain cases, but no consistent patterns were observed. CT and 99mTc SC scans are useful for determining the extent and severity of Gaucher's disease involvement of bone marrow.

Bone Diseases↗
PubMed1985

Chondrosarcoma of the spine: an unusual radiographic presentation.

Chondrosarcoma is a primary malignant tumor arising rarely in the axial skeleton. It usually presents as a destructive lesion with diffuse mottled calcification. We report three patients with chondrosarcoma of the spine. Each patient was evaluated by conventional radiographic technique, computed tomography, and myelography. All of them show radiographically a purely destructive process of the body and in one case the body and lamina. This pattern remains to be documented in the radiologic literature.

Adult↗
PubMed1985

Brucellosis: serological methods compared.

At least 12 persons contracted clinical, and 4 persons subclinical Brucella melitensis infection during a brucellosis epidemic in the spring and summer of 1983 in Southern Germany, a region which had been free of this disease for the past 20 years. All cases of illness were traced to one infected herd of sheep. The presence of antibodies against B. melitensis was examined in 72 sera of infected patients using the following tests: agglutination, Coomb's test, two complement fixation tests with different antigen preparations (CFT 1 and 2), IgG and IgM enzyme-linked immunosorbent assay (ELISA), and opsonophagocytosis; and the occurrence of cross-reacting antibodies against Yersinia enterocolitica O 9 was investigated in the agglutination and complement fixation tests. Sera from 100 blood donors and 112 other people with close contact with sheep were also examined. The results revealed the need to consider an intermediate range in the interpretation of ELISA results--due to elevated values of persons in groups at risk but without clinical signs of illness. In all other tests, however, such persons revealed the same cut-off levels as the general population. Results from all initial sera of infected persons revealed titres of optical densities above the baseline levels determined in the present study, with the exception of the Coomb's and CFT2 tests. The agglutination test, but not brucella CFT2, revealed complete cross-reactivity between Y. enterocolitica O 9 and B. melitensis. ELISA stood out as the only test which is suited to diagnosis of both recent and past infection, since ELISA IgM determination permits conclusions about the time of the onset of illness, and determination of IgG may still yield values above the cut-off level up to 623 days after the onset of illness. In 2 of the 16 infected persons, IgG ELISA was the only test revealing previous infection 424 and 528 days after the onset of illness. A procedural scheme is presented which may help to simplify the diagnosis of brucellosis.

Agglutination Tests↗
PubMed1985

[Role of x-ray computed tomography in infectious spondylodiscitis. A review article].

The importance of computed tomography (CT) in the diagnosis of infectious spondylitis is reviewed on the basis of the currently available literature and our updated experience. The etiology and pathogenesis of the various types of presentation is briefly discussed. CT is an excellent non-invasive modality offering easy evaluation of the intra and extraosseous extent of the lesion, guidance to biopsy and in following therapeutic results. CT is compared with conventional techniques and its diagnostic value discussed in both the early and progressive stages of the disease.

Adult↗
PubMed1984

Optimal response planes and canal convergence in secondary neurons in vestibular nuclei of alert cats.

Responses to natural stimulation were studied in electrically identified secondary vestibular neurons of awake cats. A class of neurons was identified whose response dynamics and responses to rotations in several vertical and horizontal planes indicated that they received semicircular canal input. Each canal neuron had clearly defined planes of maximal and null sensitivity to rotation. The orientation of these planes indicated that 44% of the neurons received input from one pair of canals, 40% from two, and 16% from all 3 canal pairs. Many cells also had oculomotor-related discharges and/or responded weakly to neck rotation.

Animals↗
PubMed1984

Spatial and temporal response properties of secondary neurons that receive convergent input in vestibular nuclei of alert cats.

Responses to rotation in many vertical and horizontal planes were studied in electrically identified secondary vestibular neurons of alert cats. This report concerns secondary neurons that gave responses which could not be explained as due to a summation of semicircular canal inputs. These cells responded to sinusoidal rotation of the cat in any vertical plane, and response phase depended on the plane of rotation. The responses were modeled as the result of summation of two inputs that differed in their spatial orientations and dynamics. Response dynamics and a comparison of responses to vertical and horizontal rotations showed that some cells were sensitive to rotation with respect to gravity. Their responses both to gravity and horizontal rotations argue that these secondary neurons received convergent otolith and canal inputs. Some cells also had oculomotor related discharges and/or responded weakly to neck rotation.

Animals↗
PubMed1984

Tumor infiltration of the bone marrow: comparative study using computed tomography.

During the past two years five patients with malignant primary bone tumors undergoing amputation or resection of the involved bone had preoperative computed tomography (CT) examination of the medullary cavity. The contralateral extremity was used as a control in all cases. The positive attenuation coefficient of the marrow indicated the extent of tumor infiltration. The correlation between the preoperative CT and pathologic measurement ranged between 1-8 mm, an accuracy greater than 94%.

Adolescent↗
PubMed1984

Cytologic observations on the effects of metallocene dichlorides on human fibroblasts cultivated in vitro.

The effects of the organometallic cytostatic agents titanocene dichloride (TDC) and vanadocene dichloride (VDC) and of the inorganic cytostatic drug cis-diamminedichloroplatinum(II) (DDP) on the morphologic appearance of human embryonal fibroblasts cultivated as monolayers in vitro were analyzed by light and electron microscopy. All three substances induced similar structural changes which consisted of nuclear as well as cytoplasmic alterations. Many fibroblasts enlarged but the nuclear volume increased more extensively than that of the cytoplasm. The nuclear envelopes underwent invagination so that segmented nuclei were formed and the nucleoli increased in size and density. Within the cytoplasm there was evidence of conspicuous protein synthesis, characterized morphologically by an increase in the size and number of mitochondria, Golgi apparatuses and of cisternae of the rER. The phenomena observed are interpreted as indicating unbalanced cell growth characterized by a selective inhibition of DNA synthesis, coupled with progressive RNA and protein syntheses.

Cell Nucleus↗
PubMed1984

Computed tomography of soft-tissue lesions of the extremities, pelvic and shoulder girdles: sonographic and pathological correlations.

Sixty-five patients with various soft-tissue tumours were examined by computed tomography (CT) and ultrasonography. Results were correlated with pathological findings. Although an accurate histological prediction could not be made in most cases, certain patterns appeared to be characteristic of specific types of tumours. A lipoma of uniformly low density may be differentiated from the heterogeneously denser liposarcoma. Multiple irregular linear densities with calcification are characteristic of haemangioma. An echo-free mass on the sonogram with soft-tissue density on CT suggests lymphoma or certain sarcomas. Small isodense subcutaneous lipomas or intramuscular lymphomatous masses may be clearly delineated on sonogram but not seen on CT. Our study indicates that the combined use of CT and ultrasound gives a very detailed basis for planning the surgical approach to the tumour.

Adolescent↗