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Biomedical subjects

K Neumann

Publications and source records attributed to K Neumann.

At least 145 records · Page 8Linked to original sources
PubMed1992

[Primary humerus head replacement in dislocated proximal humeral fracture. Indications, technique, results].

Displaced three- and four-part fractures of the humeral head detached from their blood supply are at high risk for a poor functional outcome after internal fixation. Primary prosthetic replacement can restore the pretraumatic anatomy, and early function is possible. Head replacement within 2 weeks after trauma, reapproximation of the tuberosities, and reconstruction of the rotator cuff tear establishes early stability and good functional results in up to 80%.

Aged↗
PubMed1991

Increased rCBF in gray matter heterotopias detected by SPECT using 99mTc hexamethyl-propylenamine oxime.

Imaging findings of morphology and regional cerebral blood flow in two patients suffering from epileptic seizures are presented. CT and MRI revealed heterotopic gray matter as a probable structural correlate, causing the seizure disorder. 99mTc hexamethyl-propylenamine oxime (HM-PAO) SPECT demonstrated focally increased regional cerebral blood flow in both patients in the areas of their heterotopic lesions. Heterotopic and orthotopic gray matter seem to have similar features in terms of regional perfusion. A focally increased brain perfusion in interictal epileptic patients may indicate an underlying migration anomaly.

Adult↗
PubMed1991

Reduction in HLA-DR antigen density on alveolar macrophages of smokers.

The expression of HLA class II genes is essential to the antigen-presenting function of monocytes and macrophages. With a new cytofluorometric method of single-cell analysis we investigated the density of HLA-DR antigen expression on alveolar macrophages (AM) of smokers. Although all AM of nonsmokers (100 +/- 1%) expressed HLA-DR antigens, only 79 +/- 12% of AM from smokers showed positive findings (p less than 0.001). Furthermore, the antigen density of those cells expressing this antigen was significantly reduced in smokers (p less than 0.001). The defective expression of class II genes on AM of smokers might contribute to the impaired antigen-presenting function found by some previous investigators.

Antibodies, Monoclonal↗
PubMed1991

[Prepontine artifacts due to cerebrospinal fluid pulsation in the T-2 weighted coronal MRT picture. Clinical significance, frequency, technique for artifact suppression].

Coronal T2-weighted MRI is the most sensitive imaging modality to detect temporal lobe pathology. However, prepontine artifacts resulting from pulsation of cerebrospinal fluid occasionally simulate temporal lobe lesion. To characterize this artifact we studied 30 patients without temporal lobe pathology in conventional T2-weighted spin-echo technique (0.5 T, SE 1600/70, coronal, horizontal phase encoding). Visual analysis revealed high-intensity artifacts simulating a lesion in five of 30 cases. The present study shows that prepontine artifacts due to pulsation of cerebrospinal fluid are quite frequent (17%) and that these artifacts may result in misinterpretation in the evaluation of temporal lobe epilepsy. By a repeat examination in identical methodology while using vertical phase encoding, all artifacts could be identified and an artifact-free representation of the temporal lobes was achieved.

Adult↗
PubMed1991

[Gadolinium-DTPA as an oral contrast medium for magnetic resonance tomography of the pancreas].

52 patients with normal pancreas, pancreatitis and pancreatic tumors were examined by magnetic resonance imaging (Magnetom 0.5 T). Using T1-, proton density- and T2-weighted spin-echo sequences images were obtained before and after oral administration of Gadolinium-DTPA (Gd-DTPA, 1 mM, 15 g/l Mannit, 5-13 ml/kg). Gd-DTPA resulted in hyperintense labeling of small bowel in all sequences and improved visualization of pancreatic head, body and tail in 15, 14 and 7 of 27 patients with normal pancreas and in 17, 8 and 6 of 25 patients with diseased pancreas. Better delineation of pseudocysts and tumorous gut wall invasion were diagnostically profitable. With regard to motion artifact reduced MRI of the intestine using fast sequences Gd-DTPA may be a suitable oral contrast agent to improve the imaging of the pancreas.

Administration, Oral↗
PubMed1991

[Magnetic resonance tomographic screening studies of the bone marrow with gradient echo sequences: (I) the contrast relations of phase-identical and phase-shifted gradient echo sequences. Studies on probands and pathological-anatomical preparations].

Anatomical specimens and normal persons were studied by gradient echo MR imaging to determine the influence of different echo times (TE) on bone marrow contrast. First of all, six normal persons were studied to determine specific echo times for in-phase and opposed-phase states. Using different sequences bone marrow contrast in isolated femoral bones was determined and compared to results of pathological exams. Red bone marrow had no signal on opposed-phase images; contrast between red and yellow marrow was higher on opposed-phase than on in-phase images. Bone marrow lesions can be expected to be visualised with high signal on opposed-phase images; this technique should be especially suited for MR imaging of bone marrow.

Adult↗
PubMed1991

[The differential diagnosis of liver metastasis and regional fatty liver: a comparison of CT and MRT].

Differentiation between liver metastases and local fat deposition may be difficult when using CT; the value of MRI was therefore investigated in 18 patients with metastases and ten patients with fat deposits. CT shows both lesions as similar hypodense areas. MRI, however, produces different appearances: T1- and 2-weighted images show marked differences in the signal arising from metastases, whereas local fat collections in both sequences differ little in their signal from normal liver. Quantitative MRI signal intensity of the two types of lesion were also different. Where the differentiation by CT may be difficult, it may be made with certainty by means of MRI.

Adult↗
PubMed1991

Silver-stained structures in prostatic carcinoma: evaluation of diagnostic and prognostic relevance by automated image analysis.

The comparison of the diagnostic and prognostic significance of histology, immunohistochemical parameters (PSA, PSP), and silver-stained nucleolar organizer regions (AgNORs) was estimated in paraffin sections taken of 63 prostatic carcinomas prior to therapy. AgNORs were visualized with a one-step silver staining technique with the appropiate staining time determined by preliminary staining-time series. The mean AgNOR number per cell (n) and the mean AgNOR area per silver-stained dot (A) were determined by means of an automatic image analysis system. Thereby prostatic carcinomas exhibited multiple small AgNORs within their nuclei (n = 4.7, A = 0.09 micron 2), whereas benign prostatic epithelium showed few but large silver-stained particles (n = 1.8, A = 0.27 micron 2; p less than 0.001). This relationship was then calculated as a quotient of AgNOR number and area (NQ = n/A) which provided additional information for the diagnosis of malignancy as well as survival. Univariate survival analysis disclosed a set of four variables predicting death from prostatic cancer; cribriform growth pattern, AgNOR quotient, histological grade, and PSA immunoreactivity. Of these parameters, immunoreactivity of PSA failed to prove its prognostic significance in multivariate survival analysis (Cox model). No relation to prognosis was found for the number as well as the area of AgNORs alone. Therefore, image analysis proved to be a prerequisit for the feasibility of this promising technique by providing objective and reproducible results.

Acid Phosphatase↗
PubMed1991

[Axis-related spontaneous correction after tibial fractures in childhood].

In the Department of Surgery at the Bergmannsheil University Hospital, a total of 50 children with measurable post-traumatic deformity of the axis after fracture of the lower limb were examined. Clinical and radiological monitoring was carried out 6 years after their accidents, which they had sustained at the age of 3-15 years. The real degree of axis deformity remaining was determined mathematically, and the correction tendency was analysed in three dimensions and projected graphically using sum vectors. This showed better results in the correction of axis deformations of the lower limb visualized on a-p X-ray photographs as varus or valgus than of deformations seen as ante- and recurvation of lateral X-ray photographs. The excentric arrangement of muscles in the dorsal part of the lower limb could be one reason for this. All 50 patients experienced a reliable spontaneous correction of the axis deformity with no complications of stimulatory growth disturbance with showing good functional results. Shaft fractures of the lower limb in children are generally treated conservatively, operative treatment being indicated only in the case of severe lesions of the soft tissue and in adolescent patients.

Adolescent↗
PubMed1991

[A histologically controlled study of the value of sonography and palpation for the detection and exclusion of neck lymph node enlargements and metastases].

Preoperative evaluation of cervical lymph nodes by ultrasound and palpation was compared retrospectively in 123 patients with tumours on the head and neck. The diagnostic accuracy was higher by ultrasound (96.5%) than by palpation (85.5%). Hence, the sensitivity for detecting cervical metastases was also higher for ultrasound than for palpation (96% versus 83%), because of the reduced false negative findings. Specificity, however, was higher for palpation (82%) than for ultrasound (74%). Ultrasound was superior in delineating the relationship of metastases to adjacent tissues (vessels). Major disadvantages of ultrasound were the higher percentage of false positive findings (26%) and absence if delineation of the relationship to bony structures.

Adult↗
PubMed1991

The fine structure of testicular interstitial cells in the mouse. A comparison after conventional double fixation versus rapid freezing followed by freeze substitution.

The interstitial cells in the testis of the mouse have been studied both after conventional double fixation with glutaraldehyde followed by osmium tetroxide and after rapid freezing and cryosubstitution with osmium tetroxide-acetone by light, scanning and transmission electron microscopy. Differences have been found especially concerning the preservation of lipids and the appearance of mitochondria. Varying proportions and different aspects of rough and smooth endoplasmic reticulum were observed corresponding after both preparation methods thus confirming their real existence. Numerous specific contacts are found between macrophages and Leydig cells, indicating a functional interdependence between these two cell types. Though structural preservation is superior after freeze substitution in the outermost zone, artifacts caused by the initial impact, by ice crystal formation, and during substitution must be considered.

Animals↗
PubMed1991

[Arthrolysis of post-traumatic stiff elbow. Which factors influence the end result].

In a retrospective study of 59 patients the results obtained with elbow arthrolysis performed for the treatment of posttraumatic stiffness were analyzed. The intraoperative functional result was classified as excellent in all cases, while an average of 27 months after the operation the range of movement was decreased again to varying extents. This deficit correlated with the type of injury, timing of arthrolysis, duration of metal implants and timing and type of postoperative rehabilitation program. The relative increase in function was better after simple fractures, with 47%, than after fracture dislocations, with 35%. After arthrolysis within 3 months of onset of posttraumatic stiffness the range of improvement was 55%, compared with an increase of only 30% after 10 months' stiffness. When arthrolysis was combined with metal removal and the implants had been in place for longer than 9 months the increase achieved was only 15%. Patients mobilized on the 1st day postoperatively lost only 15% of their intraoperative function. If mobilization was delayed to between the 2nd and 5th days, 30% was lost. Changing splints for maximal joint flexion and extension at 4-h intervals resulted in a 35% loss of range of movement postoperatively. In contrast there was a loss of only 17% in the group with combined additional physiotherapy and continuous passive motion. The results show that the prognosis of elbow arthrolysis is determined by optimal operative planning and a meticulous rehabilitation program. The time to arthrolysis should be as short as possible, as should the time to removal of metal implants. The aim of the rehabilitation program is immediate postoperative mobilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Multiple myeloma of the bladder and vagina.

A case is described of multiple myeloma with involvement of the urinary bladder and vagina. The patient was admitted with hematuria and postrenal obstruction. She was treated successfully with local radiotherapy and combination chemotherapy with vincristine, Adriamycin (doxorubicin), and dexamethasone (VAD).

Aged↗
PubMed1990

Differentiation capacity of human non-small-cell lung cancer cell lines after exposure to phorbol ester.

Three cell lines of squamous-cell carcinoma and 3 of large-cell carcinoma origin were investigated for the expression of differentiation markers and functional parameters (proliferation, morphology, cornified envelope formation, involucrin staining, transglutaminase activity, adhesiveness and migration) under normal cell culture conditions and after treatment with the tumor promoter phorbol-12-myristate-13-acetate (PMA). Although all original tumors had been described as poorly differentiated by histological grading, we found significant heterogeneity in the expression of differentiation markers in cell culture. A systematic grading of the cell lines became possible only after PMA stimulation. PMA generally increased expression of differentiation markers in cell lines of comparably low grades of differentiation, as indicated by dose-dependent inhibition of proliferation and cloning efficiency, induction of squamous markers, and decreased adhesiveness and cell motility. In contrast, cell lines of apparently higher differentiation by these criteria showed little response to PMA. The results presented show that the assessment of differentiation capacity by comparison of differentiation markers under normal cell culture and PMA-stimulated conditions in established NSCLC cell lines allows for a refined cell culture grading, which might advance the classification and characterization of such cell lines which, otherwise, appear to be very heterogeneous. It may also help to correlate cellular functions with various states of differentiation in vitro.

Biomarkers, Tumor↗
PubMed1990

A cytofluorometric method to quantify membrane antigens on individual alveolar macrophages.

An immunofluorescence method for assaying membrane-bound antigens on individual alveolar macrophages (AM) collected by bronchoalveolar lavage (BAL) is described. Cells were labelled with FITC-conjugated anti-HLA-DR antibodies in a single (direct) step. Quantification of the fluorescence was performed by computer-assisted cytophotometry. Alveolar macrophages, especially when obtained from cigarette smokers, exhibited an autofluorescence which interfered with the measurement of specific fluorescence. The specific fluorescence was calculated by determination of total fluorescence in the wave-length optimal for FITC and the non-specific fluorescence in a different wavelength during a second measurement. Specificity and reproducibility testing confirmed the reliability of the method.

Analysis of Variance↗
PubMed1990

Assessment of nucleolar organizer regions by automatic image analysis in breast cancer: correlation with DNA content, proliferation rate, receptor status and histopathological grading.

The value of automatic image analysis in the investigation of nucleolus regions (AgNOR) has been examined in tissue sections of 52 malignant and 30 benign breast lesions. Determination of the AgNOR number per cell alone revealed a considerable overlap between benign (range 1.2-3.8) and malignant specimens (range 1.5-16.2). They differed however, highly significantly (P less than 0.001) in their AgNOR sizes. In benign breast disorders the mean AgNOR area per tumour ranged from 0.22 microns2 to 1.07 microns2 (mean 0.39 microns2), whereas in carcinomas AgNOR sites ranged from 0.05 microns2 to 0.22 microns2 (mean 0.09 microns2). AgNOR counts showed a good correlation with histopathological grade (P less than 0.05), aneuploidy (P less than 0.01), proliferation rate as determined by Ki67 immunostaining (P less than 0.01), as well as oestrogen and progesterone receptor content (P less than 0.01). Image analysis proved to be advantageous over AgNOR counting alone as it facilitated the standardization of the AgNOR technique itself and thus, significantly improved its diagnostic specifity.

Breast Neoplasms↗