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Biomedical subjects

M Fink

Publications and source records attributed to M Fink.

At least 253 records · Page 14Linked to original sources
PubMed1983

Ultrasonic signal processing for in vivo attenuation measurement: short time Fourier analysis.

Short-time Fourier analysis is well suited for processing tissue echographic signals which are nonstationary. We have investigated the use of short-time Fourier analysis to provide an estimation of the echographic spectral composition as a function of time. It will be shown that the time dependence of the spectral centroid of this representation allows one to deduce easily the frequency-dependent attenuation. A simple correction of the noninvariant filtering effect due to diffraction is used to unbias the attenuation slope estimation. This new signal processing technique was first tested on simulated echographic data from a 1-D tissue model. Experimental results obtained from echo signals on a tissue-like phantom and on in vivo liver tissue show the influence of diffraction and attenuation respectively.

Animals↗
PubMed1983

The Angelchik antireflux prosthesis. Effects on the lower esophageal sphincter of primates.

It has been shown that the ACAP causes significant increases in the LES pressure of supine primates which are maximal when properly placed at the EGJ. This effect appears to be due to posterior padding of the EGJ in supine animals and can be reproduced by dowel rods or Maloney dilators. Further studies to evaluate the contribution of this effect to the prevention of acid reflux are underway.

Animals↗
PubMed1982

Monitoring the duration of electroconvulsive therapy seizures: 'cuff' and EEG methods compared.

Seizure durations in electroconvulsive therapy (ECT) were determined by both EEG and BP cuff methods in 20 patients receiving 225 seizures. The estimates were highly correlated, with cuff estimates 10% shorter than those by EEG. Routine monitoring of seizure duration by the BP cuff method is recommended, particularly in unilateral ECT. Monitoring seizure time should resolve controversies over the efficacy of different forms of ECT, as well as improve clinical practice where disturbing reports of missed seizures are now documented.

Aged↗
PubMed1982

Biopterin level in peripheral blood cells as a marker for hemopoietic cell proliferation during leukemia and polycythemia vera.

Using the Crithidia assay 3.0 ng biopterin/ml blood was found, of which one third was present in the plasma. The erythrocyte fraction comprised 1.7 ng and the buffy coat 0.33 ng. After Ficoll separation 0.050 ng were found in the lymphocyte layer of 1 ml blood. During blast crisis of chronic myelocytic leukemias increased amounts of biopterin were found in the erythrocyte fraction and in the buffy coat. The high biopterin concentration per unit of protein in the white cell fraction indicated the presence of blasts. In Polycythemia vera increased amounts of biopterin in both the red cell fraction and in the buffy coat were also found but the percentage distribution within total cellular biopterin was markedly shifted toward the erythrocyte fraction. In cases of chronic and acute lymphocytic leukemias the low amounts of biopterin in the red cell fraction agreed with the current view of partial extinction of the erythropoietic line. The isolated lymphoblasts were characterized by high biopterin concentrations per unit of protein. During remission the biopterin patterns approached normal levels.

Biopterins↗
PubMed1982

Pharmaco-EEG study of 6-azamianserin (ORG 3770): dissociation of EEG and pharmacologic predictors of antidepressant activity.

The effects of a single oral dose of 6-azamianserin (2 mg) were compared to those of mianserin (6 mg), flurazepam (10 mg), and placebo in 11 healthy male volunteers, in a crossover design. Quantitative EEG, heart rate, blood pressure, task performance, and subjective state were measured. EEG and behavioral measures distinguished the substances from placebo. 6-Azamianserin was similar to mianserin in type and duration of effects. In a separate study in 12 volunteers, 0.5 and 1.0 mg of the (+) and (-) enantiomers of 6-azamianserin elicited dose-related EEG and behavioral effects, distinguishable from placebo. These effects were similar to those elicited by racemic 6-azamianserin and mianserin. Clinical trials of 6-azamianserin in depressed patients, particularly the elderly and those with cardiovascular disease, are warranted. Dosages selected should be one-third those of mianserin. The stereospecific properties of the enantiomers in preclinical tests predict that any clinical 'antidepressant' activity will reside in the (+) isomer only, while the pharmaco-EEG trials predict that both enantiomers will be clinically 'antidepressant'. Clinical testing of the isomers, particularly the (-) isomer, is indicated as a test of the predictive value of pharmacologic and pharmaco-EEG models of clinical antidepressant activity.

Adult↗
PubMed1982

Central nervous system effects of aspirin.

The EEG effects of aspirin at single doses of 0.65 and 1.95 gm were studied in normal adult men. Compared to placebo, 1.95 gm affected the quantitative EEG, symptom self reports, and cognitive functions. The effects of 0.65 gm. were similar in direction and pattern, but failed measurable significance. The EEG profile of aspirin is distinct from that of other psychoactive substances. Its interaction with sedative substances should be considered in routine clinical use.

Adult↗
PubMed1982

Mianserin.

Explore the source record for details and available documents.

Animals↗
PubMed1982

ECT in anxiety: an appraisal.

Convulsive therapy is a specific therapy for patients with melancholia and catatonia, with a high success rate. There is little evidence, however, to encourage its use in patients with anxiety, or in the many subtypes of neuroses in which anxiety is prominent. Indeed, the principal contraindication to the use of convulsive therapy is the presence of anxiety, and patients with this syndrome should be shielded from this therapy.

Anxiety Disorders↗
PubMed1982

Blood levels and the quantitative EEG response to CNS-active drugs: retrospective observations.

Quantitative EEG measures provide reliable, non-invasive indices of CNS effects of drugs in man. In pharmaco-EEG studies of CNS-active substances, we found that EEG changes correlated with blood drug levels within individuals over time, and showed the correlation to be replicable. Across individuals at single times, however, correlations were not evident. In seeking relationships across subjects, techniques which adjust for EEG baseline differences between subjects are under investigation.

Adult↗
PubMed1982

Pteridine-binding alpha 1-acid glycoprotein from blood of patients with neoplastic diseases.

A glycoprotein was selectively enriched in the supernatant (Fraction b) obtained by alcohol and trichloroacetic acid fractionation of digitonin extracts from blood of patients with neoplastic diseases and of control subjects. Subsequent chromatography with concanavalin A:Sepharose separated a concanavalin A-reactive fraction from a concanavalin A-nonreactive one. In sodium dodecyl sulfate gel electrophoresis, the fractions from both malignant origin as well as control subjects appeared as single bands showing the same mobility. They were identical with the band obtained from commercial alpha 1-acid glycoprotein. In Fraction b of malignant origin, greatly increased amounts of the alpha 1-acid glycoprotein from malignant cases (AGPM) were found as compared to alpha 1-acid glycoprotein from controls (AGPC). Furthermore, AGPC had a higher glycine content than did AGPM. The electrofocusing pattern of AGPM showed additional bands between pH 3.7 and 4.4, whereas AGPC and commercial alpha 1-acid glycoprotein focused between pH 3.2 and 3.8. In contrast to AGPC and to a commercial alpha 1-acid glycoprotein, AGPM is characterized by a chromophoric group with maximal absorbance at 400 nm. It could be detached by treatment with 6 M guanidine hydrochloride thus indicating a noncovalent binding. The spectral data on the separated chromophore at pH 0.5 agreed with that of a 6,7-substituted pteridine. After detachment with reducing agents, a pteridine in its 7,8-dihydro form was indicated by spectral analysis.

Amino Acids↗
PubMed1982

Blood levels of a pteridine-binding alpha 1-acid glycoprotein in cancer patients.

A variant of alpha 1-acid glycoprotein was found previously in blood of malignant cases. It had been characterized as a pteridine-binding alpha 1-acid glycoprotein (P-AGPM). P-AGPM as well as the corresponding fraction of control origin were selectively enriched in the supernatant (Fraction b), obtained after digitonin extraction and subsequent alcohol and trichloroacetic acid fractionation of whole blood. In Fraction b, alpha 1-acid glycoprotein from control subjects + P-AGPM comprised 90 to 95% of total protein; it was quantitated by colorimetric determination of the protein-bound tyrosine and calibrated with the isolated compound. During a screening of malignant and nonmalignant cases, P-AGPM proved to be an acute-phase reactant to some extent. Marked increases during extended cancer and especially during leukemias corroborated the view that P-AGPM may be identical with abnormal orosomucoid. Longitudinal sections during leukemias suggested that the biopterin of leukemic cells may be metabolically related to the pteridine moiety of P-AGPM. Biopterin determinations by means of Crithidia assay in the blood of 136 cases of solid tumors showed that, due to its high rate of renal clearance, blood biopterin is not a reliable and persistent marker for proliferative activity, unless it is contained in the immature blood cells themselves, as is the case during leukemias.

Biopterins↗