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Biomedical subjects

F Fischer

Publications and source records attributed to F Fischer.

At least 55 records · Page 3Linked to original sources
PubMed1990

[N-acetylneuraminic acid (sialic acid) as a tumor marker in head and neck cancers].

N-acetyl-neuraminic-acid (sialic acid) is a natural component of the cell surface. Cancer cells show a higher concentration of sialic acid in the cell membrane, and the serum also shows an elevated level of sialic acid. The concentration of sialic acid was measured in the serum of 76 new tumour patients and 113 previously treated patients who were clinically free of recurrence. The primary tumour was classified as T1-T4 according to the UICC classification. A further group consisted of patients with recurrent tumours. The values were compared with the sialic acid concentration in the sera of 63 healthy probands. Patients with manifest tumours showed an increased level of sialic acid that correlated with the extent of the tumour. The sialic acid level in 71% of patients with a recurrence lay above the upper limit of normal (82 mg/dl) recorded in the sera of healthy probands. The measurement of the serum sialic acid is a useful parameter for early detection of recurrence.

Biomarkers, Tumor↗
PubMed1989

Staurosporine stimulates expression of the urokinase-type (u-PA) plasminogen activator in LLC-PK1 cells.

In LLC-PK1 porcine epithelial cells, the urokinase-type plasminogen activator (u-PA) mRNA and protein can be induced either by stimulation of the protein kinase C (PKC) pathway using a tumor promoter (PMA) or by stimulation of the protein kinase A (PKA) pathway with calcitonin (SCT). By contrast, addition of 10(-7) M staurosporine, an inhibitor of PKC, to LLC-PK1 cells also stimulated urokinase production. In contrast to the in vitro situation (where staurosporine inhibited PKC activity), in the cell-culture system the microbial agent caused an early translocation of PKC and inhibited PKA. Addition of staurosporine together with PMA or with SCT further increased urokinase mRNA and protein synthesis. Maximal stimulation was obtained when all 3 agents were added together. We thus assume that in LLC-PK1 cells the PKA and PKC signal-transferring pathways can function independently.

Alkaloids↗
PubMed1989

Experimental autonomic neuropathy in the choroid of streptozotocin-diabetic rats. Electron microscopic observations.

The authors used transmission electron microscopy to examine the autonomic nerve plexus of the choroid, in Wistar albino rats with long-term streptozotocin diabetes. Axonal alterations included massive glycogen deposits, honeycomb arrangement of synaptic vesicles, and an accumulation of dense, lamellated, tubulovesicular and multivesicular bodies within the transmitter segments. The alterations affected not only the neuroeffector areas of arterial and venous vessels, but also the close contacts between transmitter segments and melanocytes. Morphometric analysis lead the authors to conclude that the axonal alterations do not simply represent accentuation of age-related phenomena. Instead, they should be considered as manifestations of diabetic autonomic neuropathy.

Animals↗
PubMed1989

[The lingual thyroid, an unexpected and rare intubation difficulty].

A patient scheduled for a gynecological operation could be intubated only after various repeated attempts. The cause of the airway obstruction was an ectopic thyroid at the right base of the tongue, which made visualization of the glottis impossible. Management and prevention of the unexpected difficult intubation are discussed.

Adult↗
PubMed1985

An improved preservation technique for cells of hemopoietic origin.

A new technique for the cryopreservation of cell lines of hemopoietic origin is described. It uses a combination of 10% polyvinylpyrrolidone or hydroxyethylstarch with 15% glycerol, a slow stepwise addition of the cryoprotectants before freezing, cooling at 4 degrees C/min, rapid rewarming, and a slow step-wise dilution after thawing. This technique has given improved recovery rates with a number of basophil/mast cell lines, as well as a wide range of hemopoietic cells including hybridomas.

Animals↗
PubMed1985

Growth-factor-independent proliferation in vitro and tumorigenicity in vivo are associated in basophil/mast-cell lines and their somatic hybrids.

According to a current model, leukemic cells arise from normal hemopoietic progenitors as a result of two phenotypic changes: (1) a shift from a high to a low probability of completing differentiation, and (2) the loss of requirement for physiological growth regulators, such as multilineage hemopoietic growth factor (MHGF). In agreement with this model, we have recently reported that the spontaneous, in vitro, malignant transformation of a factor-dependent basophil/mast-cell line was coincidental with the appearance of MHGF-independent proliferation in vitro. We have now fused the MHGF-independent cells with their nontransformed counterparts. In the present study, 29 out of 32 hybrid clones analyzed exhibited an association between, on the one hand, the absence of MHGF requirement in vitro and high tumorigenicity in vivo and, on the other hand, MHGF-dependent proliferation in vitro and a reduced capacity to make tumors in vivo. These data support the idea that the tumorigenic behavior of the transformed cells in vivo and their lack of requirement for MHGF in vitro are directly related.

Animals↗
PubMed1983

Chemolithoautotrophic metabolism of anaerobic extremely thermophilic archaebacteria.

Several types of extremely thermophilic archaebacteria have recently been isolated from solfataric water holes, hot springs and hot sea floors. It has been shown that some of them can live using sulphur respiration of reduced carbon substrates as a source of energy, a type of metabolism previously described for the eubacterium Desulfuromonas. We report here that several extremely thermophilic archaebacteria can live with carbon dioxide as their sole carbon source, obtaining energy from the oxidation of hydrogen by sulphur, producing hydrogen sulphide. They are thus capable of a new type of anaerobic, purely chemolithoautotrophic metabolism, a possible primaeval mode of life.

Anaerobiosis↗
PubMed1983

Morphometric analysis of basal laminae in rats with long-term streptozotocin diabetes L. II. Retinal capillaries.

Twelve months after onset of streptozotocin-induced diabetes in rats, the basal lamina width of peripheral retinal capillaries, as measured with two different morphometric methods, is increased only in the basal lamina regions adjacent to perivascular glial cells. In the region between endothelial cells and pericytes no increase of thickness was observed. These facts support the suggestion of a predominantly glial (neuroectodermal) contribution to basal lamina thickening of retinal capillaries in diabetes mellitus. No correlation exists between the degree of basal lamina thickening at the different anatomic sites. Furthermore, no clear-cut correlation was found between basal lamina thickening and severity of the metabolic disease.

Animals↗
PubMed1982

[Proliferating retinopathy in diabetes mellitus. Clinical and autopsy results].

UNLABELLED: Clinical and autoptic investigations of thirty patients suffering from diabetes mellitus and retinopathia proliferans result in these findings: Of the various manifestations of angiopathy only retinopathy (leading symptom), nephropathy, and arterial hypertension are present in all cases, all other forms receeding into the background numerically, though not in potency. 20 cases of nephropathy ended in uremia (cause of death), 10 cases in azotemia. In 14 out of 20 cases of uremia specific glomerulosclerosis (M. Kimmelstiel-Wilson) was stated autoptically, in the remaining 6 cases a different form of nephropathy was found (pyelonephritis, arteriosclerosis renum, chronic glomerulonephritis). In the 10 patients suffering from azotemia, direct causes of death were various general diseases, such as coronary sclerosis, encephalomalacia, pyogenic infections, and acute tuberculosis. CONCLUSION: Diabetes mellitus in connection with retinopathia proliferans turns out to be the most serious form of the general diabetic disease.

Adolescent↗
PubMed1982

Newly isolated Friend cell lines are blocked at the same stage of erythroid differentiation as established clones.

Friend erythroleukemia cells, a widely used in vitro model of murine erythropoiesis, express prior to induction, a state of erythroid differentiation similar to that of the early erythroblast in vivo. To investigate whether this uniform and stable epigenetic state was the result of a selection in long-term culture for the corresponding cell type, 29 new cell lines were isolated from the hemopoietic organs of DBA/2 mice infected with Friend virus and were analyzed without delay for the expression of several erythroid traits. All the lines examined displayed levels of expression of the markers indistinguishable from those displayed by established Friend cell clones. Thus, newly isolated Friend cell lines appear to be blocked at essentially the same stage of erythroid differentiation as established clones. This indicates that the expression of several characteristic erythroid markers is remarkably stable in vitro and does not result from long-term selection. In contrast, the capacity of these cells to respond to chemical inducers varies considerably from clone to clone and with time in culture.

Animals↗
PubMed1982

[Diabetics with proliferative retinopathy of unusual course (author's transl)].

General experience shows that proliferative diabetic retinopathy leads to blindness within only a short time, in spite of short-term improvements in the clinical picture. Long-lasting remission can occur, but seldom for more than a few years. We have observed 3 patients with proliferative retinopathy in whom remission continued for more than 15 years, in one case even lasting over 20 years. Good, useful vision was maintained during all this time. This was only true of one eye, however, while the other eye rapidly became blind. Of the other forms of angiopathy, little coronary heart disease and no peripheral vascular disease was observed in these patients. There were also no signs of nephropathy, i.e. diabetes-specific glomerular sclerosis. Thus, the total picture of angiopathy seems to be benign. The remission of the retinopathy seems to be in accord with this general trend, although it can perhaps be partly explained by unknown local factors in the eye itself.

Aged↗