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Biomedical subjects

P Petzold

Publications and source records attributed to P Petzold.

7 recordsLinked to original sources
PubMed2003

Effect of calcium carbonate on bioavailability of orally administered gemifloxacin.

We investigated the effect of calcium carbonate on the oral bioavailability of gemifloxacin. Gemifloxacin was administered alone, 2 h before, simultaneously, or 2 h after calcium carbonate in 16 volunteers. Data for 320 mg of gemifloxacin alone were as follows: maximum concentration of drug in serum (C(max)),13 microg/ml; half-life, 7.33 h; and area under the concentration-time curve from 0 h to infinity (AUC( infinity )), 6.79 microg. h/ml. Only simultaneous coadministration of calcium carbonate reduced C(max) (-17%) and AUC( infinity ) (-21%) significantly.

Administration, Oral↗
PubMed2001

Higher order sequential effects in psychophysical judgments.

We found that the depth of sequential effects depends on the judgment task. An experiment with squares indicated that stimulus-response pairs up to two trials back were included in the judgment process when subjects were required to make category judgments of size, whereas only the immediately preceding event was incorporated when subjects were making magnitude estimations. In the case of category judgment, interactions between the current stimulus and prior stimuli as well as configural effects indicated that events one and two trials back meet an equivalent function in the judgment process and that these events may jointly operate in one trial. These findings can be explained by a class of models that assume that the position of preceding stimuli relative to the current stimulus is decisive in the judgment process. The multiple-standards model is a representative of this class according to which there are two types of standards: (1) the endpoints of the range as long-term standards and (2) traces of preceding stimuli as short-term standards.

Adult↗
PubMed1984

Binding of five monoclonal anti-CEA antibodies with different epitope specificities to various carcinoma tissues.

Five monoclonal antibodies that recognize different epitopes on carcinoembryonic antigen (CEA) were reacted with tissue sections of various carcinoma specimens. The vital, non-necrotic tissues of those carcinomas of the oesophagus, pancreas, colon and rectum, medullary thyroid, ovary and cervix in which CEA related epitopes were detectable bound all five antibodies to a similar degree. In 3/5 lung carcinomas, 2/10 mammary carcinomas and 1/5 gastric carcinomas, a significantly different binding of the monoclonal antibodies by vital tumour tissue was present as determined by three independent investigators. In necrotic tissue areas, heterogeneity of antibody binding was more common. In a previous investigation, it was shown that normal granulocytes and liver tissue differentially bind the monoclonal anti-CEA antibodies, indicating the presence of crossreacting antigens. The equivalent binding of the five monoclonal anti-CEA antibodies to most of the carcinomas tested suggests that this binding is due to the presence of complete CEA molecules and not only of cross-reacting antigens.

Antibodies, Monoclonal↗
PubMed1981

Distance effects on sequential dependencies in categorical judgments.

Two forms of sequential dependency have been found in an auditory identification experiment: assimilation produced by the previous response and contrast caused by the preceding stimulus. The strength of these phenomena partly depends on the distance between stimuli and responses. For example, the strength of assimilation brought about by the previous response decreases with increased separation between successive stimuli. An inverse distance effect was observed for contrast caused by the preceding stimulus, which is equivalent to that found in the case of contrast produced by extraserial anchors. Observed response probabilities exhibit complicated dependencies on the current stimulus and the previous response that are not explained by existing models. An alternative model is suggested that is capable of accounting for these dependencies and for the distance effects. This model contains two mechanisms to explain sequential dependencies: The trace of the preceding stimulus acts as an internal standard, and the previous response influences a guessing strategy.

Discrimination Learning↗
PubMed1977

[Cytological accuracy of intraepithelial atypical findings on the uterine cervix].

At the municipal hospital for women in Darmstadt 223 prestages and commencing phases of the cervix-carcinoma were determined histologically from 1/1/1972 to 31/3/1976. In almost half of all low-grade dysplasias we were at first surprised due to our prospective cytologic statement. Examining all preparations, we found cytomorphologic criteria indicating dysplastic alterations. These are cytologic cell complexes with a distinct anisonucleosis without tumordiathesis. By this knowledge the registration quota of slightly dysplastic alterations could be raised to abt. 65%. The failure quota regarding the prospective cytologic statement "pre-invasion" amounts to abt. a quarter of all preformations. The results will be discussed in the connection with cytologic alterations and the histomorphologic building of intraepithelial atypias.

Carcinoma in Situ↗
PubMed1977

[Therapeutic procedure in prospective cytodiagnosis].

If the prospective cytology speaks for an intraepithelial atypia, it is possible, due to an extended gynecologic indication, (descensus uterus myomatosus, etc.) to make a primary hysterectomy, avoiding a conisation. As well the complication of the conisation and the eventually following hysterectomy, as as second hospitalisation will thus be avoided. Only twice in 101 cases the cytologic prospective statement of pre-invasion could not be confirmed. These were cases of microinvasion in the sense of a "reticular infiltration". We made no further error "upwards". This proceeding for the diagnosis and therapy of early alterations at the portio uteri can only be carried out in clinics with gynecologically-clinically experienced cytologists. The clearing by conisation of cytologically not definite findings continues to remain the leading principle.

Adult↗