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Biomedical subjects

A Schulz

Publications and source records attributed to A Schulz.

At least 181 records · Page 10Linked to original sources
PubMed1988

[Iridocyclectomy using a lamellar explorative technic. Long-term studies].

The question as to whether lamellar explorative iridocyclectomy always enables the spread of tumors of the iris base or ciliary body to be detected beyond doubt was verified in 11 patients who had been treated by this procedure more than four years previously. Seven of the patients were available for reexamination. In two special cases it was found that this was not true. In the other patients neither histologic findings nor long-term follow-up revealed any tumor spread beyond the excision area, and in particular no invasion of the sclera.

Aged↗
PubMed1988

Establishment and characterization of a permanent human IgA2/kappa myeloma cell line.

A human myeloma cell line designated LOPRA-1 has been established from ascites fluid containing malignant plasma cells of a patient with IgA2/kappa multiple myeloma. The cultured cells which are Epstein-Barr virus (EBV) negative have retained the morphological, cytochemical, ultrastructural and immunophenotypical features of well-differentiated plasma cells. They express the plasma cell antigen PCA-1, the antigens CD28 (Kolt-2) and CD38 (OKT10), the transferrin-receptor (OKT9), and some epitopes of the CD24 antigen (HB8, VIB E3), but are negative for surface immunoglobulins. HLA class II antigens (HLA-DP, -DQ, -DR) and other B-cell markers such as CD10 (CALLA), CD19 (B4), CD20 (B1), CD21 (B2), CD22 (HD39), CD23 (MHM6), CD37 (BL14) and CD39 (G28-8) as analysed by both flow cytometry and immunocytochemistry (PAP/APAAP). With respect to immunoglobulin synthesis, two stable clones were selected by single cell cloning: clone LOPRA-1/5 synthesizes large amounts of alpha 2 heavy and kappa light chains, but secretes only small amounts of these molecules, whereas clone LOPRA-1/4 is clearly devoid of intracellular immunoglobulin heavy and light chains and thus appears to be a chain loss variant. Cytogenetic analysis revealed a pseudotriploid phenotype with several structurally abnormal marker chromosomes: 3n + -, 70, XX, -X, -1, -4, -6, -8, -8, -13, -16, +7, +18, +21, +i(1q), +i(1q), +6q-, +3mar.

Cell Line↗
PubMed1988

Immunohistochemical study of osteonectin in various types of osteosarcoma.

Polyclonal antibodies against osteonectin, a 32 kd non-collagenous bone protein, were applied for the histogenetic identification of variously differentiated osteosarcoma tissues. A strong positive reaction was found in matrix-producing osteosarcoma cells of the osteoblastic type, but pleomorphic or fibrosarcomatous osteosarcoma tissues reacted focally positive as well. Because the production of osteonectin depends on the osteoblastlike function of the individual tumor cell, a homogeneous immunocytochemical staining of all tumor cells cannot be expected. Nevertheless, the immunocytochemical demonstration of osteonectin in osteolytic tumors that produce no or scarcely any matrix seems to be a valuable tool for establishment of their osteogenic origin.

Animals↗
PubMed1988

[Classification, clinical aspects and diagnostic pathology of soft tissue tumors].

Soft tissue tumors often present a clinical problem, and their histology is heterogeneous. It is only in the last 15 years that an internationally accepted classification has been widely used to assess prognosis and determine therapy. In the present article the important clinical aspects of treatment are presented in combination with new therapeutic and diagnostic discoveries. Immunohistochemistry is now more widely used as an accepted diagnostic method than electron microscopy.

Biomarkers, Tumor↗
PubMed1987

[Osteocalcin and bone histology in osteoporosis].

The decoupling of bone formation and bone resorption causes an insidious bone loss that is responsible for the negative skeletal balance in the frequent form of low turnover osteoporosis. The reduction of bone formation can hardly be verified by clinical methods. Osteocalcin, a non-collagenous bone protein, has proved to be a useful new indicator of bone formation. To establish its predictable value, plasma levels of osteocalcin were compared to conventional serological data of bone turnover and to histomorphometric parameters of iliac crest trabecular bone. In cases of osteoporosis with normal bone turnover activity (as confirmed by histomorphometry) no differences were observed in any of our laboratory data including osteocalcin. However, there was a significant lower mean serum level of osteocalcin in a group of patients with histomorphometrically proven low turnover osteoporosis in comparison to those with normal bone turnover. Serum levels of osteocalcin below 2.0 ng/ml seem to indicate a low turnover in the individual case of osteoporosis while this is unlikely when serum levels above 6.0 ng/ml are measured (according to our RIA).

Adult↗
PubMed1987

Osteonectin--a differentiation marker of bone cells.

Bone matrix consists of type-I collagen and non-collagenous proteins. The latter represent only 10% of its total protein content. Since type-I collagen is also present in various other connective tissue sites (e.g., skin) it cannot be considered as bone specific. Among the non-collagenous components osteonectin--a 32 kilodalton (KD) glycoprotein linking mineral to collagen fibrils--is thought to be bone specific due to its biochemical properties. In the present study various skeletal and non-skeletal tissues were investigated for the presence of osteonectin by means of immunocytochemical methods. Two polyclonal antibodies against human and bovine osteonectin were applied. Immunocytochemically, osteonectin could be demonstrated in active osteoblasts and osteoprogenitor cells as well as in young osteocytes, while aged, quiescent osteocytes did not contain the protein, suggesting that the protein is a marker of the osteoblastic functional differentiation of bone cells. Osteonectin was absent in all non-skeletal tissues with the exception of chondrocytes in so-called mineralizing chondroid bone.

Antibodies↗
PubMed1987

Absence of a clinically significant interaction between theophylline and furosemide.

In new of previous contradictory results, the possible interaction between the loop diuretic furosemide and theophylline was re-evaluated in 12 healthy volunteers with a steady-state plasma theophylline level. Two doses of furosemide 20 mg at a 4 h interval did not influence the steady-state plasma concentration of theophylline despite causing a moderate diuresis. Urinary recovery of theophylline and its metabolites amounted to 106 +/- 21% of the dose without furosemide and 96 +/- 19% of the dose with furosemide, demonstrating that there was no influence on the enteral absorption of theophylline of the furosemide treatment. After the first dose of furosemide the fractional renal clearance (CLR1) of theophylline (fractional = hourly sampling period) changed in parallel with the urinary flow rate, without a significant difference between treatment with and without furosemide. After the second dose of furosemide, CLR1 was increased in the first hour and then it declined to levels far lower than the control value. This unexpected result could explain the unchanged plasma concentration of theophylline during furosemide treatment.

Adult↗
PubMed1987

Uptake of Glyphosate by an Arthrobacter sp.

The uptake of glyphosate (N-[phosphonomethyl]glycine) by an Arthrobacter sp. which can utilize this herbicide as its sole source of phosphorus was investigated. Orthophosphate suppressed the expression of the uptake system for glyphosate and also competed with glyphosate for uptake. The K(m) for glyphosate uptake was 125 muM, and the K(i) for orthophosphate was 24 muM. Organophosphonates as well as organophosphates inhibited glyphosate uptake, but only organophosphates and orthophosphate suppressed the uptake system. Glyphosate uptake was energy dependent, had a pH optimum of 6 to 7, and was differentially affected by divalent cations.

Journal Article↗
PubMed1986

Pancreatic endocrine carcinoma with ectopic PTH-production and paraneoplastic hypercalcaemia.

In a case of pancreatic endocrine carcinoma hypercalcaemia without bone metastases and normal parathyroid glands prompted our suspicion that there was paraneoplastic production of an osteoclast activating substance by the tumour tissue. This view was further confirmed by bone histology. Immunohistology post mortem revealed the production of PTH in the primary tumour and a liver metastasis. The usefulness of immunohistology in detecting paraneoplastic secretion of hormonal substances is discussed.

Cytoplasmic Granules↗
PubMed1986

Overproduction of 5-enolpyruvylshikimate-3-phosphate synthase in a glyphosate-tolerant Petunia hybrida cell line.

Analysis of a Petunia hybrida cell culture (MP4-G) resistant to 1 mM glyphosate revealed a 15- to 20-fold increased level of 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase in the herbicide-tolerant strain. Immunoblotting and enzyme kinetic measurements established that the increased EPSP synthase activity resulted from overproduction of a herbicide-sensitive form of the enzyme. Homogeneous enzyme preparations were obtained from the herbicide-tolerant cell line by sequential ion-exchange, hydroxyapatite, hydrophobic-interaction, and molecular sieve chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and molecular sieve chromatography established the Petunia enzyme to be a monomeric protein with Mr 49,000-55,800. Km values for phosphoenolpyruvate and shikimate 3-phosphate were about 14 and 18 microM, respectively. Glyphosate inhibited the enzyme competitively with phosphoenolpyruvate (Ki = 0.17 microM). These experiments provide further evidence that EPSP synthase is a major site of glyphosate action in plant cells.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1986

Immunocytochemical markers (endothelial and histiocytic) and ultrastructure of primary aneurysmal bone cysts.

Since the first description of an aneurysmal bone cyst in 1942, the pathogenesis of this tumor-like lesion has been controversial. Aspects of interest for elucidating the nature of this lesion include the cellular linings of the aneurysmal cavity systems as well as the character and cellular composition of the stromal septa. To clarify these features, seven aneurysmal bone cysts were studied electron microscopically and immunocytochemically with endothelial (Factor VIII-related antigen, monoclonal endothelial marker) and histiocytic (alpha 1-antitrypsin, alpha 1-antichymotrypsin, lysozyme, acid phosphatase) markers. Both immunocytochemical and electron microscopic examination revealed that the aneurysmal cavernous spaces have no endothelial lining but are delimited by fibroblasts and histiocytic cell forms at varying stages of differentiation. These cell forms are also the main component of the mononuclear stroma cells of the septa between the aneurysmal cavities. From these findings it is concluded that the aneurysmal cavities are not vascular. The sinusoidal septal capillaries might play a special role in their pathogenesis. Due to the lack of basal membrane structures, rupture of the wall gives rise to erythrocyte extravasates, which can undergo secondary transformation into cysts.

Adolescent↗