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Biomedical subjects

M Fischer

Publications and source records attributed to M Fischer.

At least 523 records · Page 29Linked to original sources
PubMed1990

[Percutaneous transvascular pulmonary valvuloplasty. Early and late results].

Since the introduction into practice in may 1986 at the Institute of Cardiovascular Diagnostics we performed 45 valvuloplasties until March 1990 in 34 children (6.2 +/- 4.9 years old) and 11 adults (29.5 +/- 9.6 years) with valvular pulmonary stenosis. The invasively obtained pressure gradient at the valve diminished from 83.4 +/- 30.7 mm Hg to 35.7 +/- 19.0 mm Hg. Intraoperative complications in three patients (short term asystole, severe bradycardia, increase of right ventricular pressure to 300 mm Hg after valvuloplasty) were controlled, but demanded the end of the intervention. No significant insufficiency of pulmonary valves after valvuloplasty was seen. 18 patients were clinically investigated 14.6 +/- 9.4 months after intervention. The late results for these patients proved the method as a long term curing treatment. According to our present results pulmonary valvuloplasty is the alternative method for valve surgery especially in critical pulmonary valve stenosis in newborns.

Adult↗
PubMed1990

[The morphologic reaction pattern to fiber dust].

In principle, the fibrosing, preneoplastic and neoplastic morphological reactions to natural and man-made mineral fibres are relatively uniform, and are thus non-specific for the various different types of fibre. In order to establish a causal chain between the injurious "fibrous" agent and the morphologically and clinically manifest pathological lesion, close cooperation between epidemiologists, occupational physicians, pneumologists and pathologists is needed. On its own, the morphological contribution towards solving the problem is of only a limited nature. Light-microscopic, electron-microscopic and element-analytical studies, however, used in conjunction with the results obtained in animal experiments, in the individual case with consideration also being given to aspects of medical insurance, can lead to useful information for the clinical situation and for the generation of expertize.

Air Pollutants, Occupational↗
PubMed1990

[The value of surgical therapy in the treatment of urogenital tuberculosis].

A series of 94 patients treated over a period of 22 years for genitourinary tuberculosis is reviewed. The group was made up of 72 patients with isolated urinary tuberculosis, 12 with isolated tuberculosis of the genitalia and 12 with combined disease. In 70 patients surgery was performed in addition to the standardized chemotherapy. Of the 72 patients with urinary tuberculosis, 21 received exclusively conservative treatment, while 16 underwent conservative surgery and the remaining 35, ablational surgery. The high nephrectomy and overall operation rate is explained by the high percentage of advanced state of disease and a large number of patients referred to us for nephrectomy following long-term conservative treatment. A retrospective justification for this procedure is found in the fact that 52% of the surgical specimens showed florid tuberculosis though the patients had been receiving standardized chemotherapy for an average of 9 months.

Adolescent↗
PubMed1990

[Antagonizing the effect of midazolam by flumazenil in gastroscopy: results of a randomized double blind study].

The action and side effects of the benzodiazepine antagonist Flumazenil were evaluated and compared with placebo in a double blind parallel group randomized trial involving 40 patients having upper gastrointestinal endoscopy under Midazolam premedication. Flumazenil reversed the hypnotic effect of midazolam within a few minutes. The patients were alert, cooperative, oriented and had recall of events after endoscopy. The effects were better than placebo concerning alertness for up to 30 minutes after administration whereas drowsiness remained almost stable after placebo. Time to reach full alertness was shorter after Flumazenil compared with placebo (42 vs 62 minutes). There were no significant side effects. Flumazenil allows effective reversal of midazolam premedication after upper gastrointestinal endoscopy.

Adolescent↗
PubMed1990

Low-dose subcutaneous recombinant interleukin-2 in advanced human malignancy: a phase II outpatient study.

Recombinant interleukin-2 (rIL-2; EuroCetus, Amsterdam, Netherlands) was studied in an outpatient phase II trial in 14 patients with progressive metastatic renal carcinoma, malignant melanoma, and colorectal cancer. Escalating doses of rIL-2 were administered as subcutaneous bolus every 12 hours, starting at 0.3 million U/m2/d. A 100% dose increase occurred at weekly intervals, up to a maximum of 2.4 million U/m2/d. Responding patients or patients with stable disease after 4 weeks of rIL-2 (n = 9) were continued on maintenance therapy at 1.8 million U/m2 of rIL-2 administered once weekly. After 12 weeks of therapy, one renal cell cancer patient had a partial regression in lung metastases. Bolus injection of rIL-2 (1.2 million U/m2) resulted in peak serum levels of 25 to 30 U/ml. Toxicity of this regimen was moderate, with local inflammation at the injection sites, grade I-II (World Health Organization) malaise, nausea and/or vomiting, and fevers in 70% to 100% of patients treated. Thyroid dysfunction was observed in 10 patients receiving subcutaneous rIL-2; four of these patients had laboratory evidence of hyperthyroidism, and one had hypothyroidism. rIL-2-induced toxicity reversed spontaneously after cessation of treatment. In all patients receiving rIL-2, a dose-dependent increase in peripheral blood lymphocyte and eosinophil counts was noted, with a mean of 2.6 and 3.8 x 1,000/microliters after 4 weeks of therapy; mean lymphocyte and eosinophil counts were measured at 2.0 and 2.4 x 1,000/microliters in patients who received prior high-dose chemotherapy, compared with 3.2 and 5.1 x 1,000/microliters in those who did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Anorexia↗
PubMed1989

Determination of urinary 3-methoxy-4-hydroxyphenylethylene glycol and its conjugates by high-performance liquid chromatography with electrochemical and ultraviolet absorbance detection.

A simple method for the determination in urine of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) and its conjugated derivatives is described. After an extraction procedure similar to that described by Gaertner and Wiatr [J. Clin. Chem. Clin. Biochem., 18 (1980) 579] isocratic high-performance liquid chromatographic separation is performed. MHPG can be detected by either electrochemical or absorbance detection (278 nm). Free MHPG is determined directly, whereas MHPG sulphate and MHPG glucuronide are determined after enzymic hydrolysis. Since total MHPG, which represents the sum of these substances, is determined separately, a comparison of the results allows the effectiveness of the hydrolysis of the MHPG derivatives for each urine sample to be determined. For quantitation, the method of adding standard amounts of MHPG is used.

Chromatography, High Pressure Liquid↗
PubMed1989

Distinct patterns of lymphokine requirement for the proliferation of various subpopulations of activated thymocytes in a single cell assay.

The frequency and capacity for clonal expansion of several murine thymocyte subpopulations responsive to various IL (fetal day 15, and adult CD4-8-, CD4+8- and CD4-8+) were investigated using a single-cell limiting-dilution cell culture system without filler cells. This assay requires the presence of PMA and ionomycin. The main conclusions of these studies are the following: 1) IL-4 is a better growth factor than IL-2 for immature thymocytes (fetal day 15 or adult CD4-8-). 2) IL-2 is a better growth factor than IL-4 for mature phenotype thymocytes (CD4+8- and CD4-8+). 3) IL-4 is a relatively poor growth factor for adult CD4-CD8- thymocytes and CD4+CD8- thymocytes, while it induced strong responses in fetal day 15 and CD4-8+ thymocytes. 4) IL-6 enhanced the response of CD4+8- thymocytes to either IL-2 or IL-4. 5) Cortisone-resistant thymocytes grown initially with IL-4 and then switched to IL-2 showed a significant decrease in cloning efficiency. No inhibitory effect was observed when cells were cultured first with IL-2 and then switched to IL-4. 6) Finally, supernatant from Con-A stimulated rat spleen cells induced maximal growth of all adult thymocyte populations tested, suggesting that unidentified thymocyte growth factor(s) remain to be characterized. These results indicate that the maturational stage of thymocytes determines their requirements for activation and proliferation.

Animals↗
PubMed1989

Lipocortin I and lipocortin II inhibit phosphoinositide- and polyphosphoinositide-specific phospholipase C. The effect results from interaction with the substrates.

Lipocortins I and II, known to inhibit phospholipase A2, have been purified from bovine lung and tested with respect to their ability to affect the enzymatic activities of phosphoinositide- and polyphosphoinositide-specific phospholipase C from human platelets, rat liver cytosol or rat brain membranes. At 0.67 microM, both lipocortins led to complete inhibition of phospholipase C activity with either phosphatidylinositol or phosphatidylinositol 4,5-bisphosphate as substrate. The inhibition could be overcome by increasing the substrate concentration. Ultracentrifugation studies with lipocortin II showed a direct interaction between phosphatidylinositol and the lipocortin, indicating that the lipocortins inhibit phospholipase C not directly but by interacting with the substrate. In experiments with plasma membranes from [3H]inositol-labeled HL-60 cells, lipocortin II did not affect PI-specific phospholipase C activity in the absence or presence of calcium plus or minus GTP-gamma-S.

Animals↗
PubMed1989

[The lateral capsule sign in the traumatized knee joint].

The lateral capsular sign is a simple radiographic finding visible on routine anteroposterior knee x-ray near the tibial articular surface at the lateral point of the lateral tibial plateau. The lateral capsular sign is a flake of bone superior and posterior to the insertion of the iliotibial tract, and represents an avulsion of the meniscotibial portion of the lateral capsular ligament. A positive lateral capsular sign implies disruption of the lateral capsule and a tear of the anterior cruciate ligament. These findings are illustrated by clinical examples.

Humans↗
PubMed1989

Measurement of regional cerebral blood flow and accentuation of the primary auditory cortex with single photon emission computed tomography.

Conventional brain scanning uses polar tracers which do not penetrate the normal blood-brain barrier. Radiolabeled amines like 123-iodoamphetamine (IMP) cross the barrier to inhibit serotonin and norepinephrine in synaptosomes. Studies of cerebral perfusion and function seem to be successful with such labeling. We advance the hypothesis for an increased IMP uptake in the stimulated primary auditory cortex. The method of single photon emission computed tomography (SPECT) is described. We have also been able to demonstrate marking of the primary auditory cortex by an increased amphetamine input in 6 out of 15 cases during stimulation by white noise.

Acoustic Stimulation↗
PubMed1989

Semiquantitative analyses of dynamic single photon emission computed tomography (SPECT) of the primary auditory cortex.

To date it has not been possible to work out a standard quantification for single photon emission computed tomography (SPECT). Only one mathematical model has received general recognition, but the theoretical preconditions for this model are not fulfilled by iodine-amphetamine kinetics. A practical solution is offered by semiquantitative analysis. We have developed three computer programs for this analysis for perfusion and cerebral function studies of the symmetrically arranged brain.

Adult↗
PubMed1989

Characterization of cloned antigens of Taenia ovis.

Fusion proteins derived from recombinant clones of Escherichia coli carrying the pEX series of expression vectors with cDNA inserts of the tapeworm, Taenia ovis, were characterized by their antigenicity when administered to mice and sheep. Antisera derived from these hosts were shown to react with a number of T. ovis adult worm and oncospheral antigens in Western blots, and to bind to oncospheres and worm tissue in fluorescent antibody tests. Epitopes produced by two clones (designated T07 and T08) are found on several antigenic polypeptides of T. ovis and a related species T. hydatigena. Those produced by a third clone (T03) are specific to T. ovis. The immunological results were confirmed by Northern blotting of T. ovis and T. hydatigena RNA: RNA transcripts corresponding to T07 and T08 are found in both T. ovis and T. hydatigena, whereas RNA corresponding to T03 is found in T. ovis only. Cross reacting epitopes in fusion proteins from T07 and T08 appear to have different amino acid sequences, and T. ovis antigenic epitopes are shared by a number of polypeptides in and between adult worms and oncospheres.

Animals↗
PubMed1989

Mechanisms of short-term (second range) regulation of the activities of enzymes of lipid and phospholipid metabolism in secretory cells.

In isolated guinea pig parotid gland lobules the activities of the following enzymes were measured 30 sec after stimulation with either 2 X 10(-5) M isoproterenol or 10(-5) M carbachol: glycerol kinase (EC 2.7.1.30), glycerolphosphate acyltransferase (EC 2.3.1.15), lysophosphatidate acyltransferase (EC 2.3.1.51), phosphatidate phosphohydrolase (EC 3.1.3.4), diacylglycerol acyltransferase (EC 2.3.1.20), diacylglycerol kinase (EC 2.7.1.107), and CDP-diacylglycerol synthetase (EC 2.7.7.41). Lyso-phosphatidate acyltransferase, diacylglycerol kinase, and diacylglycerol acyltransferase exhibited significant increases following stimulation by both types of agonists. Stimulation of the activities of these three enzymes occurred also following in vitro incubation with the catalytic subunit of cAMP-dependent protein kinase or a Ca2+/calmodulin-dependent protein kinase II. These effects could be reversed by incubation with various protein phosphatases. When cells were first stimulated with either type of agonist, subsequent incubation with protein kinases was almost ineffective. Activation by the two types of protein kinases was not additive, indicating that they activate by phosphorylating identical sites on the enzyme proteins. The other enzymes examined showed no or only minor changes and their activities could not be affected by in vitro incubation with the two types of protein kinases. The results explain the rapid changes in acyl-group transfer from acyl-CoA to neutral lipids observed previously during the first seconds after stimulation of guinea pig parotid gland lobules with isoproterenol or carbachol (1). An analysis of a potential role of lipocortins for the regulation of phosphoinositide-specific phospholipases C reveals that these proteins do indeed inhibit these enzymes, but that this inhibition results from a calcium-dependent interaction of the lipocortins with the phospholipid substrate. A physiological role of lipocortins for the regulation of phospholipases is doubtful.

Acyltransferases↗
PubMed1989

Role of interleukin-4 in T-cell ontogeny: changes in cell surface phenotype and lymphokine production of immature thymocytes after culture with interleukin-4 and phorbol ester.

We have analyzed the phenotype and functional capabilities of adult and fetal CD4 8 thymocytes after 4 d of culture in IL-4 and PMA. Both adult and day 14 fetal CD4 8 thymocytes failed to acquire CD4 or CD8 antigens following culture. However, changes in expression of other antigens typical of immature thymocytes were observed. For example, the frequency with which cells expressed high levels of J11d or IL-2-R was greatly decreased following culture, whereas the frequency with which high levels of MEL-14, the lymph node homing receptor were expressed were greatly increased. This phenomenon may be due to direct induction by IL-4 and PMA of MEL-14 expression on purified MEL-14lo CD4-8- thymocytes. The frequency of cells expressing CD3, Ly-1 and Pgp-1 changed only slightly. Functionally, the cultured cells produced large amounts of interferon gamma but very little IL-2 or IL-4, although freshly isolated CD4-8- thymocytes produced all three lymphokines. These results suggest that in addition to a proliferative stimulus, culture in IL-4/PMA alters the expression of several early thymocyte antigens, the functional capabilities of CD4-8- progenitor thymocytes, and may act as a selective differentiation stimulus to MEL-14lo CD4-8- thymocytes.

Animals↗
PubMed1989

Detection of HBV DNA in HBsAg-positive sera after amplification using the polymerase chain reaction.

The presence of hepatitis B virus (HBV) DNA in serum as detected by molecular hybridization is considered the most reliable marker for the presence of complete virions and, therefore, infectivity. This technique, however, has a lower limit of detection of 0.1 pg HBV DNA. Using the polymerase chain reaction (PCR), a technique by which DNA sequences can be amplified selectively, we investigated sera from 30 HBsAg carriers, 6 also positive for HBeAg and 24 negative for HBeAg. After PCR followed by Southern blot, 27 sera were found to be positive for HBV DNA, whereas only 7 sera were positive for HBV DNA in the conventional dot blot. PCR followed by Southern blot analysis lowered the limit of detection to 0.5 fg HBV DNA. Amplified HBV DNA fragments from some samples were directly sequenced without previous cloning. We conclude that PCR is a suitable method to amplify parts of viral genomes present in human sera, and that PCR with subsequent Southern blot analysis allows the detection of hepatitis B virions in the majority of HBsAg-positive sera.

Blotting, Southern↗
PubMed1989

pH-controlled continuous cultivation of mycoplasmas.

The continuous cultivation of mycoplasmas in a pH-controlled metabolistat was investigated with the fermentative strain Mycoplasma mobile 163K and the nonfermentative strain Mycoplasma arthritidis ISR1. The addition of medium and the removal of culture suspension were regulated by acid production from glucose by M. mobile 163K and by ammonium production from arginine by M. arthritidis ISR1, respectively. For both strains the optimal pH for continuous growth was 7.0. The steady state could be maintained for at least 21 days. With CFU of 8.4 X 10(9) ml-1 (M. mobile 163K) and 3.2 X 10(9) ml-1 (M. arthritidis ISR1), the cell concentrations were slightly higher than those obtained in batch cultures. The dependence on the adjusted pH values was measured for several parameters, such as flow rate, CFU, glucose fermentation or production of ammonia, and gliding velocity. Since the long lag phases of batch cultures can be avoided, pH-controlled continuous cultures provide an appropriate system for the production of mycoplasma cells.

Acetates↗
PubMed1989

[Increase of scientifico-technical information availability on food and nutrition].

This article presents the evolution and development that the Programmatic Area of Dissemination of Scientific and Technical Information of INCAP has had during the last five years. It therefore includes, objectives, activities conducted, and a description of achieved products, as well as short and medium-term perspectives foreseen.

Academies and Institutes↗