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Biomedical subjects

L Senf

Publications and source records attributed to L Senf.

At least 19 recordsLinked to original sources
PubMed2001

Isochromosome 1q as an early genetic event in a child with intracranial ependymoma characterized by molecular cytogenetics.

Data concerning cytogenetic features of childhood ependymoma are rare. In this article, a gain of 1q was identified as the sole alteration in a primary childhood infratentorial ependymoma by comparative genomic hybridization (CGH). A recurrence of this brain tumor was studied using multiplex-fluorescence in situ hybridization (M-FISH) in addition to CGH and G-banding analysis. In accordance with the primary tumor, a gain of 1q corresponding to an isochromosome 1q was observed indicating an early event in the tumor development. Furthermore, M-FISH classified several other rearranged chromosomes including 6q and 17p that have previously been found to be involved in the development and progression of childhood ependymoma.

Brain Neoplasms↗
PubMed1995

Analysis of the GAP-related domain of the neurofibromatosis type 1 (NF1) gene in childhood brain tumors.

The neurofibromatosis type-1 (NF1) gene contains a 360-bp region with significant homology to the catalytic domain of mammalian GTPase-activating protein. This particular GAP-related domain of the NF1 gene (NF1-GRD) stimulates ras GTPase and inactivates ras protein p21ras. Therefore, it has been suggested that the NF1 gene represents another tumor-suppressor gene. In the search for molecular markers of possible diagnostic relevance, childhood brain-tumor specimens of different histologic diagnoses were tested for mutations of the so-called FLR-exon within the NF1-GRD. This part of the NF1-GRD has been shown to be most crucial for the GAP-like function. Using a highly sensitive PCR-SSCP technique, we tested 51 tumor specimens were tested, but found no mutations. We conclude that inactivation of this putative tumor-suppressor gene by mutations does not play a significant role in tumorigenesis of childhood brain tumors. Next, we compared the splice variants of the NF1-GRD in 33 brain tumors and 8 extraneural embryonal tumors. Primitive neuroectodermal tumors (PNET) (n = 10) and one intracranial teratoma were the only tumors that predominantly expressed a splice pattern that can be observed in the immature developing brain. In contrast to other embryonal neuronal tumors, this NF1-GRD splicing pattern could not be modified in a newly established medulloblastoma cell line by retinoic acid treatment. Since this particular splice variant suppresses p21ras more effectively than other NF1-GRD transcripts, its predominant expression may interfere with the physiological signal transduction of p21ras during differentiation of neurons. There may be a neurofibromin-induced and p21ras-mediated differentiation pathway of neuronal stem cells that is blocked in PNET. Such an arrest of a p21ras-dependent differentiation pathway may explain the persistence of primitive pluripotent neuronal cells in PNET.

Alternative Splicing↗
PubMed1993

[Differential liver siderosis diagnosis using quantitative iron determination in the biopsy specimen].

Quantitative iron investigations were carried out in the leavings of liver biopsy specimens from 92 patients with liver siderosis, detected by histochemical methods. A discrimination between primary and secondary liver siderosis were tried by the liver iron index. Idiopathic hemochromatosis was not found in liver iron indices below 2, both hemochromatosis and secondary liver siderosis were found with an index above 2. Only idiopathic hemochromatosis was found with an index above 5 with the exception of one transfusional siderosis in refractory anemia.

Biopsy↗
PubMed1990

[Examples for using capillary gas chromatography with wide bore columns in occupational health].

Wide bore capillary columns (0.4-0.75 mm ID) can be easily and inexpensively installed in packed column GCs. The analytical advantages cause an expanding market for such capillaries and interconverting hardware kits. It is illustrated with some examples that often individual exposition levels can be determined exactly only by using capillary columns: ethylbenzene may be separated from the C8-isomers also in complex mixtures, the marker PBN for rubber smoke expositions can be determined with 30 min sampling time, the detection sensitivity of the FID is sufficient also for chlorinated pesticides and the analyses of high-boiling compounds profit by the high phase ratio of wide bore capillary columns. A single capillary column substitutes a variety of different packed columns, so saving time and money and protecting the analyst from failures and frustrating compromises.

Air Pollutants, Occupational↗
PubMed1989

[Erythrocyte ferritin in patients with normal and abnormal iron metabolism].

Erythrocyte and serum ferritin was determined in 36 patients with different pictures of diseases and under bleeding therapy in idiopathic haemochromatosis (IH). With latent iron deficiency there was no significant difference in the ferritin content of erythrocytes in comparison with the control group. The intraerythrocyte ferritin content in idiopathic haemochromatosis is always increased and will normalize under bleeding therapy as well serum ferritin. After disrupting the therapy the ferritin content in erythrocytes will more rapidly increase again than in the serum. Increased erythrocyte ferritin could be identified in patients with anaemia due to ineffective erythropoiesis.

Anemia, Hypochromic↗
PubMed1989

[Short bowel syndrome and glucose tolerance].

There are different signs after extended small bowel resection. The length of the resected small intestine (size of resection), the location of the removed part (type of resection), the time after operation (stage of adaption) and the age of the patient define the severity and nature of complaints following small bowel resections. We examined the dynamics of glucose- and insulin level after oral and intravenous glucose administration to recognize the relation to the size of resection. We found a decreased basal insulin concentration and a diminished response of insulin after intravenous glucose load in patients with extensive small bowel resection. This reduced response after parenteral administration of glucose load we did not find in the ileum-resected group compared to control group. We can conclude, it is possible to get information about the size of small bowel resections by the intravenous glucose tolerance test.

Adaptation, Physiological↗
PubMed1989

[Studies on the long-term exposure of operating room personnel to 2-bromo-2-chloro-1,1,1-trifluorethane (Halothane)].

Different operation theatres of the county of Gera were examined to quantify the exposition against halothane which is used as an inhalation narcotic, and also against ethanol. Besides the short time exposition (0.5 h) determined with gas sampling tubes the long time exposition (up to 8 h) was monitored personally by means of charcoal passive samplers. The analytical method of choice was gas chromatography, in the second case after thermal desorption of the enriched pollutants. Generally, the concentrations are lower than the MAKD if the workplace is equipped with an exhaust type NAREX 101. Without it the MAKD is reached quickly. A statistical evaluation of the results shows that there exist remarkable differences between as well the degree as the scattering of the individual exposition levels depending from the task in the operating theatre. Obviously the percentage of anesthesia using halothane is increasing.

Air Pollutants, Occupational↗
PubMed1988

[Ferrokinetic studies with Fe-59 in idiopathic hemochromatosis and other forms of iron overload].

Conventional ferrokinetic studies were done in patients with idiopathic hemochromatosis, secondary siderosis of the liver and iron overload in consequence of sideroblastic or aplastic anaemia. By means of the isotope 59Fe we determined the clearance of radioiron from the plasma, the plasma iron turnover, the utilization of iron by the erythropoesis and the iron uptake by the liver. The later value showed a good correlation with the iron content of the liver determined by atomic absorption spectrometry as well in patients with hemochromatosis as in patients with secondary siderosis of the liver. The 59Fe uptake by the liver was normal in treated hemochromatosis. There was no correlation between the degree of the iron overload and the 59Fe uptake by the liver in patients with anaemia.

Anemia, Aplastic↗
PubMed1988

[Diagnostic significance of quantitative iron determination in gastric mucosa in iron overload].

The iron content of liver and gastric mucosa was quantitatively examined by means of atomic absorption spectrometry in 36 patients with iron overload (22 with idiopathic haemochromatosis, 14 with therapy-resistant anaemia) and in 17 subjects without anomaly of iron metabolism. Diagnostically evaluable iron deposits in gastric mucosa were only found in severe iron overload. In this case it was correlated with the hepatic iron content, and was indicative of iron-related disturbances also in other organs. The quantitative iron determination represents a diagnostic enlargement. It is indicated, if simple noninvasive methods are failing, and it should never be omitted in suspected iron overload, whenever other reasons as well are demanding gastroscopy.

Anemia, Hypochromic↗
PubMed1987

[Value of carcinoembryonic antigen (CEA) in assessing therapeutic success in small cell bronchial cancer].

UNLABELLED: The determination of the carcino-embryonal antigen (CEA) for the assessment of the therapeutic success and course in colorectal tumours is at present an established diagnostic method. In other solid tumours, e.g. in bronchial carcinomas, the therapy monitoring by means of CEA was less tested. 92 Patients were examined, 31 of them with limited disease (l. d.) and 61 with extensive disease (e. d.). The determination of the CEA was performed before and during the combined radiation therapy and polychemotherapy with 2 different protocols of treatment: ACO (adriblastin, vincristine, cyclophosphamide), FOMC (5-fluoruracil, methotrexate, vincristine, cyclophosphamide) with the OPIDI-radioimmunoassay. Normal values: 0-10 micrograms/l. Limiting area: 11-20 micrograms/l. Pathological area: greater than 20 micrograms/l. RESULTS: patients with limited disease: 8 normal, 14 in the limiting area, 9 in the pathological area (29%). Patients with extensive disease: 17 normal, 19 in the limiting area, 25 in the pathological area (42%) before the beginning of the therapy. With 54 and 60 micrograms/l, respectively, the mean values of the two groups, however, did not differ significantly. Altogether 39 of the 92 patients examined (42%) showed changes of the CEA-values during the course of the disease. For the 31 patients with limited disease 26 (84%) achieved a CR. Of these 26 patients the CEA-values were increased in 7 patients, 5 of them showed a clear decrease, in 3 patients a normalization of the CEA appeared with further existing remission, which lasts for 28, 24 and 14 months. In the remaining 2 patients in the CEA-values decreased into the limiting area.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

[Paraneoplastic endocrinopathies].

After the presentation of the definition and of several historical data the present pathophysiological imaginations concerning the problems of the ectopic hormone production are sketched which nowadays not yet have accepted a definitive form. A survey of the at present ascertained paraneoplastic endocrinopathies and several own findings allow a valuation of the significance of these phenomena in practice, taking into consideration the literature.

Hormones, Ectopic↗
PubMed1984

[Idiopathic hemochromatosis--diagnosis and therapy].

The excessive storage of iron in idiopathic haemochromatosis leads to severe organic lesion up to life-threatening conditions (cardiac insufficiency, portal decompensation). The symptoms melanodermia , diabetes mellitus and other endocrine failures, liver cirrhosis, cardiac insufficiency and arthropathy appear together or in various combinations. The diagnosis is ascertained by the proof of iron storage, the multiple organic affection and by familial accumulation of the various laboratory diagnostic possibilities are particularly to be emphasized the serum iron value together with the percetal transferrin saturation (as search test), serum ferritin, the desferrioxamine test, simple ferrokinetic investigations and the quantitative determination of iron in the liver in the bioptate . For family examinations, apart from the search test, a HLA typisation is reasonable, in order to estimate the risk of the disease (particularly of brothers and sisters). The therapy of choice are blood- lettings (0.5 l once to twice a week) up to obtaining a permanent easy iron deficiency anaemia. The maintenance therapy should be performed with monthly to quarterly blood- lettings . Only in cases exception a desferal treatment is indicated. Endocrine failures and cardiac disturbances need a particular therapy.

Adult↗
PubMed1983

[Release of chromium 51 by coxsackievirus-infected FL cells].

The time course of chromium-51 (51Cr) release was investigated on FL monolayer cells infected with different serotypes of coxsackievirus. 51Cr release was determined by means of the increase in 51Cr radioactivity in supernatants of cells saturated with 51Cr. Ten hours p.i. the 51Cr release of virus-infected cells was largely increased compared with the control cells. The greatest differences in 51Cr release between normal and virus-infected cells were observed from 10 to 30 hours p.i. The quantitative correlation between virus concentration and 51Cr release as well as the type-specific inhibition of virus-accelerated 51Cr release by virus-neutralizing antisera demonstrate the relationship between 51Cr release and coxsackievirus infection of FL cells. By the use of 51Cr labeled FL cells as an indicator system, the 51Cr release proved to be well suited for objective and quantitative evaluation of coxsackievirus-cell-interactions connected with the cytopathogenic effect (CPE).

Animals↗
PubMed1982

[Experimental studies on the diffusion of antifibrinolytic agents in fibrin thrombi. A contribution to intrathecal antifibrinolytic therapy in subarachnoid hemorrhages].

The diffusion behaviour and the diffusion coefficients of antifibrinolytics in fibrin thrombi were determined by in vitro incubating attempts with tritium marked compounds of PAMBA, AMCA, and ECA as well as by chromogenic substrate determination for contrykal. The great diffusion ability of PAMBA supports the usefulness of intrathecal therapy of subarachnoidal bleeding for blocking endogenous fibrinolysis, whereas the exogenous fibrinolysis of the fibrin thrombus closing aneurysm is inhibited by the intrathecal application.

4-Aminobenzoic Acid↗