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Biomedical subjects

G Kayser

Publications and source records attributed to G Kayser.

34 records · Page 2Linked to original sources
PubMed1987

Baroreflex setting and sensitivity in normal subjects: effects of pharmacologic inhibition of the angiotensin I converting enzyme.

Arterial blood pressure, heart rate and the response of these hemodynamic parameters to exogenous norepinephrine were investigated in healthy volunteers (daily sodium intake of 150 mmol) during a control period and after a single oral dose of 5 mg of the angiotensin I converting enzyme (ACE) inhibitor ramipril (HOE 498). Norepinephrine was infused at doses of 0.1, 0.2 and 0.3 micrograms kg-1 min-1, each for 10 minutes, during control and 3 hours after ramipril administration. Exogenous norepinephrine induced a dose-dependent increase in mean arterial blood pressure from 76.4 +/- 0.9 mm Hg during control to 85.6 +/- 1.5, 92.2 +/- 1.8 and 98.4 +/- 2.4 mm Hg, respectively. Ramipril significantly affected the baroreceptor set point with a decrease in mean blood pressure (72.1 +/- 1.7 vs 76.4 +/- 0.9 mm Hg, p less than 0.01) in the presence of unchanged heart rate (71.7 +/- 0.9 vs 73.6 +/- 1.5 min-1). Baroreceptor sensitivity, estimated by the slope of the delta blood pressure versus delta heart rate relation, was not affected by ACE inhibition. Also, the pressor effect of exogenous norepinephrine was unchanged by converting enzyme inhibition. The present results show that ACE inhibition with ramipril in sodium-replete healthy volunteers induces a decrease in blood pressure that is not accompanied by changes in heart rate, pressor sensitivity to exogenous norepinephrine or baroreceptor sensitivity.

Adult↗
PubMed1983

[Therapy results of acute leukemia 1965-1980].

At the instance of 174 patients with leukemia is demonstrated that the development to a more aggressive cytoreductive chemotherapy during the last 15 years achieved success without increasing the risk of treatment. A decisive improvement of prognosis for the acute leukemia of adult age is, however, to be expected only from new methods.

Acute Disease↗
PubMed1982

Immunoglobulin-lipid interaction. A model membrane study.

We recently presented evidence (Vandenbranden, M., De Coen, J.L., Jeener, R., Kanarek, L. and Ruysschaert, J.M. (1981) Mol. Immunol. 8, 621-631) for the existence of two conformational rabbit serum IgG immunoglobulin isomers. In the present report, their capacity to interact with lipid is investigated in model membranes. (1) One isomer, IgG(H), behaves like several intrinsic membrane proteins: it induces a large surface pressure increase when injected under a lipid monolayer in the close packed state and increases by 20-fold the conductance of a planar bilayer. The other isomer, IgG(S) doesn't interact significantly with the lipids. (2) IgG(H) marked a preference for monolayers made of lipids with a negatively charged polar headgroup and bearing unsaturations in their acyl chains. Penetration is stronger with lipid monolayer in the fluid state than in the rigid state. (3) As previously shown (Vanderbranden, M., De Coen, J.L., Jeener, R., Kanarek, L. and Ruysschaert, J.M. (1918) Mol. Immunol. 18, 621-631), circular dichroïsm spectra and antigen precipitation tests don't allow to detect any difference in the overall secondary conformation and antigen recognition properties of the two isomers. (4) Papaïn cleavage of the hinge region suppresses the hydrophobic properties of IgG towards lipid monolayers. (5) The hypothesis of a binding of the hinge region with the lipid bilayer is discussed.

Animals↗
PubMed1982

Structure-activity relationships of the B fragment of diphtheria toxin: the lipid-binding domains.

Two different lipid-associating domains have previously been identified in diphtheria toxin fragment B: one of the surface type in the N-terminus of B and one of the transverse type in its middle region. We have now determined about 85% of the primary structure of fragment B and show, here, that the middle part of fragment B contains a highly hydrophobic region of 72 amino acid residues (polarity index: 295) which includes the transverse lipid-associating domain. That this domain is actually involved in a process of membrane penetration is suggested by lipid bilayer conductance measurements of the CNBr peptides of fragment B and trypsin treatment of fragment B-multilamellar liposome complexes.

Amino Acid Sequence↗
PubMedDate not supplied

Evaluation of histochemical anthracyclin binding as potential prognostic parameter in small cell lung cancer.

In the quest to define further prognostic indicators for small cell lung cancer we have combined standard prognostic evaluation of several tissue and serum markers with monitoring the capacity of tumor cells to bind a carrier-immobilized anthracyclin at the time of diagnosis. The prospective study on 150 patients with small cell lung cancer (SCLC) was performed including the performance of immunohistochemical analysis [neuron-specific enolase (NSE), keratin, and vimentin], and serum marker measurements [NSE, carcinoembryonic antigen (CEA), and CYFRA], flanked by compilation of data on clinical staging at the time of diagnosis, cytostatic drug regimen, remission rates, and survival of the patients. As innovative test substance we synthesized and histochemically exploited carrier-immobilized doxorubicin. The cohort includes 108 men and 42 women grouped into stage I (limited disease: 69 patients; median survival: 317 days), stage IIa (extensive disease IIa: 19 patients; median survival: 244 days), and stage IIb (extensive disease IIb: 62 patients; median survival: 202 days). An oat-cell type was diagnosed in 112 patients, an intermediate cell type in 32 patients, and a combined cell type in 6 patients. Immunohistochemically, 123 tumors (82%) were positive for NSE, 75 tumors (50%) positive for keratin, and 26 tumors (18%) positive for vimentin. In 101 tumors (67%) specific intracellular binding of doxorubicin could be detected. Elevated serum levels for CEA and NSE were associated with an unfavorable prognosis of the corresponding patients (CEA, 261 days vs 467 days; NSE, 316 days vs 414 days). 137 patients received chemotherapy (median survival: 356 days) and 13 patients were not treated (median survival: 119 days). The six patients with the combined cell type and other patients with negative tumor specimen concerning the capacity to bind the anthracyclin were subject of a significantly shortened survival period irrespective of the cytostatic regimen (277 days vs. 381 days). Despite the current uncertainty of the biochemical nature of the histochemically detectable binding, the technical feasibility of the given interdisciplinary approach encourages to further pursue the documentation of anthracyclin binding.

Antibiotics, Antineoplastic↗
PubMedDate not supplied

From telepathology to virtual pathology institution: the new world of digital pathology.

Telepathology has left its childhood. Its technical development is mature, and its use for primary (frozen section) and secondary (expert consultation) diagnosis has been expanded to a great amount. This is in contrast to a virtual pathology laboratory, which is still under technical constraints. Similar to telepathology, which can also be used for e-learning and e-training in pathology, as exemplarily is demonstrated on Digital Lung Pathology (Klaus.Kayser@charite.de) at least two kinds of virtual pathology laboratories will be implemented in the near future: a) those with distributed pathologists and distributed (> or = 1) laboratories associated to individual biopsy stations/surgical theatres, and b) distributed pathologists (usually situated in one institution) and a centralized laboratory, which digitizes complete histological slides. Both scenarios are under intensive technical investigations. The features of virtual pathology comprise a virtual pathology institution (mode a) that accepts a complete case with the patient's history, clinical findings, and (pre-selected) images for first diagnosis. The diagnostic responsibility is that of a conventional institution. The Internet serves as platform for information transfer, and an open server such as the iPATH (http://telepath.patho.unibas.ch) for coordination and performance of the diagnostic procedure. The size and number of transferred images have to be limited, and usual different magnifications have to be used. The sender needs to possess experiences in image sampling techniques, which present with the most significant information. A group of pathologists is "on duty", or selects one member for a predefined duty period. The diagnostic statement of the pathologist(s) on duty is retransmitted to the sender with full responsibility. The first experiences of a virtual pathology institution group working with the iPATH server working with a small hospital of the Salomon islands are promising. A centralized virtual pathology institution (mode b) depends upon the digitalization of a complete slide, and the transfer of large sized images to different pathologists working in one institution. The technical performance of complete slide digitalization is still under development. Virtual pathology can be combined with e-learning and e-training, that will serve for a powerful daily-work-integrated pathology system. At present, e-learning systems are "stand-alone" solutions distributed on CD or via Internet. A characteristic example is the Digital Lung Pathology CD, which includes about 60 different rare and common lung diseases with some features of electronic communication. These features include access to scientific library systems (PubMed), distant measurement servers (EuroQuant), automated immunohisto-chemistry measurements, or electronic journals (Elec J Pathol Histol, www.pathology-online.org). It combines e-learning and e-training with some acoustic support. A new and complete database based upon this CD will combine e-learning and e-teaching with the actual workflow in a virtual pathology institution (mode a). The technological problems are solved and do not depend upon technical constraints such as slide scanning systems. At present, telepathology serves as promoter for a complete new landscape in diagnostic pathology, the so-called virtual pathology institution. Industrial and scientific efforts will probably allow an implementation of this technique within the next two years with exciting diagnostic and scientific perspectives.

Computer Communication Networks↗