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Biomedical subjects

E Schauenstein

Publications and source records attributed to E Schauenstein.

85 records · Page 5Linked to original sources
PubMed1967

Autoxidation of polyunsaturated esters in water: chemical structure and biological activity of the products.

When polyunsaturated esters or fatty acids are dispersed for long periods in water in the presence of air, water-soluble substances are formed in great variety. Because these short-chain products are constantly eluted by the aqueous phase and are consequently not available for further reaction in the oil phase, many intermediates of classical autoxidation can be isolated and identified. The identification of several of these compounds is described. Some of the peroxidic and nonperoxidic autoxidation products show biochemical activity-in particular, inhibition of glycolysis and of respiration during incubation with tumor cells in vitro. Minimal inhibitory concentrations of pure, isolated products have been determined for Ehrlich ascites tumor cells. Synthetic short-chain (C(4)-C(10)) hydroxylated alpha,-unsaturated aldehydes have been shown to have this action and also to cause morphological changes in these cells which quickly lead to their death. Normal cells are not affected. Possible therapeutic use of these compounds in the treatment of malignant neoplasms is discussed.

Aldehydes↗
PubMedDate not supplied

Quantification and localisation of SH-groups in human blood serum proteins.

The thiol groups of human blood serum proteins were determined after 24 hours interaction with dithionitrobenzoic-acid (DTNB) to an average of 538 +/- 60 mumol/l serum. After treatment of the serum with [35S]DTNB, autoradiograms of the protein elpherograms revealed two main peaks: The first with 63% of total activity, in the albumin region, corresponding to 0.60 SH/mol, the second with 23% of total activity, in the gamma-globulin range, corresponding to 2.2 SH/mol. After 30 minutes incubation with DTNB, or with p-chloromercuribenzoate (CMB), in freshly prepared pools of IgG only 0.2 SH/mol were found which is the expected value already known from the literature. Autoradiograms taken from serum protein elpherograms after interaction with [14C]CMB only show the main SH-peak in the albumin range. Thus it is concluded that the SH-peak in the gamma-globulin region after 24 hours incubation with [35S]DTNB is due to one highly labile S-S-bond which easily undergoes a disulfide exchange with DTNB.

Blood Proteins↗
PubMedDate not supplied

Microphotometrical quantification of protein thiols in morphologically intact cells of the cervical epithelium. I. Basic results with superficial cells of healthy women.

The investigations are based on Esterbauer's results according to which the staining of protein thiols (PSH) with DDD-Fast Blue B (Barrnett and Seligman) is of a quantitative order. Consequently, the PSH of the nucleus and the cytoplasm of superficial cells of the ectocervical epithelium of healthy women are determined to 0.3 and 4.1 X 10(-14) moles, respectively. After it has been found that the mean absorption spectrum between 310 and 238 nm of the pure proteins, the extinction at 278 nm of a cytoplasmic area (300 to 400 micron2) of unstained cells is taken as a first measure for the cytoplasmic protein content which is calculated to approximately 5 X 10(-18) moles per micron2 whereas the PSH content results to 1.9 X 10(-17) moles per micron2. From this value results a very plausible number of 3.6 SH per 10(5) g of cytoplasmic proteins.

Cell Nucleus↗
PubMedDate not supplied

Quantification of protein thiols in morphologically intact cells of the cervical epithelium. II. Effects of cell differentiation.

Protein-SH-groups (PSH) were determined quantitatively in basal (B), parabasal (P), intermediary (I) and superficial (S) cells of normal portio epithelium in order to obtain information about the correlation between PSH and cell differentiation. It was found that total PSH increase from B to S by 67 per cent, the main step occuring from B to P. Nuclear PSH drop continuously from B to S by 80 per cent. Thus, cytoplasmic PSH must raise (by 400%). The area of the increases strongly from B to S (by more than 1000%). Thus, differentiation is accompained by a drastic "dilution" of total PSH and PSH per area unit (1 micron2) both of nuclear and cytoplasm drop considerably. The findings about nuclear PSH are interpreted in terms of the loss of proliferative activity during differentiation, about cytoplamic PSH as expression of decreasing activities of PSH depending metabolic processes.

Adolescent↗
PubMedDate not supplied

[Intracellular effect of hydroxyalkenals on animal tumors (author's transl)].

When incubated for 30 min in vitro, 4-hydroxyalkenals in a 5 x 10-3 M solution react with SH-groups of soluble cytoplasmic and nuclear proteins (ProtL-SH) of Morris hepatomas 9618 A and 5123 tc, and of Ehrlich ascites tumor (EAT) cells. The extent of the reaction strongly increases with decreasing doubling time of the respective tumors. Former experiments with EAT cells have shown that the reaction with cytoplasmic ProtL-SH causes inhibition of respiration, glycolysis, and probably of other SH-controlled processes associated with cell division. The intranuclear reaction leads to an inhibition of DNA- and RNA-synthesis. In a 2 x 10-4 M solution of hydroxyalkenals, however, the reaction with cytoplasmic ProtL-SH diminishes almost completely so that no measurable inhibition of respiration and only 3% inhibition of glycolysis are observed, while 20 to 30 percent of the nuclear ProtL-SH are still blocked. This corresponds well with a previous observation that a 2 x 10-4 M solution of hydroxypentenal inhibits DNA-synthesis by 90 percent.

Aldehydes↗
PubMedDate not supplied

[Influence of pH, temperature and polarity of the solvent on the absorption of NADH+ and NADH at 260 nm (author's transl)].

Assuming a reversible equilibrium of an unfolded and a base-stacked conformation of both NADH and NAD+ the influence of pH, temperature and methanol on this equilibrium was studied as indicated by the UV-absorption of the adenine, band at 260 nm. By the addition of methanol as well as by an increase of temperature the equilibrium is shifted to the unfolded conformation. An increase of the H+ concentration seems to favor the unfolded conformation in the case of NAD+ while for NADH a decrease of the absorption coefficient is pointing to a higher percentage of the stacked conformation at lower pH. From the temperature variation of the absorption coefficients the enthalpies for the conformational change were calculated and compared with data obtained by different methods.

Hydrogen-Ion Concentration↗