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C Pfister

Publications and source records attributed to C Pfister.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Different DNA forms in cell nuclei of the lamina epithelialis mucosa of small intestines of children with growth disturbances due to enteric disease].

From children with growth retardation due to enteric disease, duodenal jejunal biopsy material was investigated. Using a modified Feulgen-reaction--acridine orange staining after acid hydrolysis according to Fukuda et al. (1986)--different DNA forms could be demonstrated in nuclei of cells of the lamina epithelialis mucosae by fluorescence microscopy. These clear cut forms of DNA by different fluorescence colours were only found in altered mucosa. The findings were discussed with regard to the possibility of mitotic disorders and cancerogenesis.

Child, Preschool↗
PubMed1989

The transitory complex between photoexcited rhodopsin and transducin. Reciprocal interaction between the retinal site in rhodopsin and the nucleotide site in transducin.

In the first step of the visual transduction cascade a photoexcited rhodopsin molecule, R*ret, binds to a GDP-carrying transducin molecule, TGDP. The R*-T interaction causes the opening of the nucleotide site in T and catalyzes the GDP/GTP exchange by allowing the release of the GDP. We have studied the influences on this R*-T transitory complex of the occupancies of the nucleotide site in T and the retinal site in rhodopsin. After elimination of the GDP released from the bound transducin, the complex, named R*ret-te (ret for retinal present, e for nucleotide site empty) remains stabilized almost indefinitely in a medium whose ionic composition is close to physiological. In this complex the bound Te retains a lasting ability to interact with GDP or GTP, and R*ret remains spectroscopically in the meta-II state, by contrast with free R*ret which decays to opsin and free retinal. Hence the R*-T interaction which opens the nucleotide site in T conversely blocks the retinal site in R*ret. Upon prolonged incubation in a low-ionic-strength medium the R*ret-Tc complex dissociates partially, but the liberated Te is then unable to rebind GDP or GTP, even in the presence of R*ret, it is probably denaturated. Upon treatment of the R*ret-Te complex by a high concentration of hydroxylamine, the retinal can be removed from the rhodopsin. The Re-Te complex remains stable and the complexed transducin keeps its capacity to bind GTP. TGTP then dissociates from Re. The liberated Re loses its capacity to interact with a new transducin. These data are integrated into a discussion of the development of the cascade. We stress that affinities, i.e. dissociation equilibrium constants, are insufficient to describe the flow of reactions triggered by one R*ret molecule. It depends on a few critical rapid binding and dissociation processes, and is practically insensitive to other slow ones, hence to the values of affinities that express only the ratio of kinetics constants. The effect of the R*-T interaction on the retinal site in rhodopsin is analogous to the effect of the binding of a G-protein on the apparent affinity of a receptor for its agonist.

Animals↗
PubMed1989

[Investigations on methods of quantitative polarization optical estimation of neutral carbohydrates in extracellular matrix].

By means of the fluorescence PAS-reaction using a Schiff-type reagent substituted with acriflavine, the neutral carbohydrates were demonstrable selectively in the human trophoblast basement membrane. The reaction product is characterized by a typical birefringence that can be measured in the polarized light. The results obtained from ascertainment of the dispersion of the birefringence before and after the histochemical reaction, as well, gave further evidence for specificity and a definite improvement of the measurement of path differences.

Acriflavine↗
PubMed1989

Sexually dimorphic level of CCK-8-like immunoreactive neuronal somata within several basal forebrain nuclei of the rat.

Using indirect immunocytochemical technique CCK-8-like immunoreactive somata could be demonstrated in different basal forebrain nuclei of adult rat (olfactory tubercle, nucleus accumbens septi, nucleus tractus diagonalis BROCA, nucleus septi medialis et lateralis, caudate-putamen-complex). The comparison of these findings with those of rapid Golgi technique and AChE histochemistry suggested that all CCK-8 immunostaining nerve cells should be aspiny neurons and, partly at least, a coexistence of CCK-8 and acetylcholine is assumed. In the number of neuronal somata with CCK-8-like immunoreactivity in all nuclei, especially in the caudate-putamen-complex, a distinct difference between male and female rats exist.

Animals↗
PubMed1989

Ablation of human colon carcinoma in nude mice by 131I-labeled monoclonal anti-carcinoembryonic antigen antibody F(ab')2 fragments.

Pooled F(ab')2 fragments of three MAbs against distinct epitopes of carcinoembryonic antigen (CEA) were used for radioimmunotherapy of nude mice bearing a subcutaneous human colon carcinoma xenograft. 9-10 d after transplantation when tumor nodules were in exponential growth, 36 mice were treated by intravenous injection of different amounts of 131I-labeled MAb F(ab')2. All 14 mice injected with a single dose of 2,200 (n = 10) or 2,800 microCi (n = 4) showed complete tumor remission. 8 of the 10 mice treated with 2,200 microCi survived in good health for 1 yr when they were killed and shown to be tumor free. Four of nine other mice treated with four fractionated doses of 400 microCi showed no tumor relapse for more than 9 mo. In contrast, all 15 mice injected with 1,600-3,000 microCi 131I-control IgG F(ab')2 showed tumor growth retardation of only 1-4 wk, and 15 of 16 mice injected with unlabeled anti-CEA MAb F(ab')2 showed unmodified tumor progression as compared with untreated mice. From tissue radioactivity distributions it was calculated that by an injection of 2,200 microCi 131I-MAb F(ab')2 a mean dose of 8,335 rad was selectively delivered to the tumor, while the tissue-absorbed radiation doses for the normal organs were: peripheral blood, 2,093; stomach, 1,668; kidney, 1,289; lung, 1,185; liver, 617; spleen, 501; small intestine, 427; large intestine, 367; bone, 337; and muscle, 198. These treatments were well tolerated since out of 19 mice with complete tumor remission only 4 required bone marrow transplantation and 17 were in good health for 6-12 mo of observation. The results demonstrate the selective destruction of established human colon carcinoma transplants by intravenous injection of either single or fractionated doses of 131I-MAb F(ab')2.

Animals↗
PubMed1989

[Fluorescence and optical polarization research on the qualitative and quantitative estimation of neutral carbohydrates in the basement membrane of human placental villi].

In the trophoblast basement membrane of human placental villi, neutral carbohydrates were investigated by means of fluorescence and polarization optical methods. By a modified fluorescence-PAS-reaction using a Schiff-type reagent substituted with acriflavine, the basement membrane could be stained selectively. The reaction product of known chemical structure is characterized by a typical birefringence that can be measured in the polarized light. The combination of the fluorescence histochemical method with the polarization optical one permits to obtain qualitative and quantitative data for the carbohydrate component and its incorporation and arrangement into the basement membrane at the molecular level.

Acriflavine↗
PubMed1989

[Signal transmission using second messengers].

Intercellular communication needs signal molecules (hormones, neurotransmitters, growth factors) emitted by a cell and recognized by targets. A widespread mechanism of cellular action of these molecules involves a membrane receptor, a GTP-dependent coupling protein, an effector which modulates the intracellular concentration of a second messenger (cAMP, cGMP, inositol triphosphate, Ca++), and a target for final effect of this second messenger (kinases, channel). Hormonal systems and visual processes in vertebrates rod outer segments are the best known examples of this mechanism; they are taken here to illustrate the state of knowledge of the interactions between the actors of the transductional enzymatic cascades.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1989

[Functional morphology of the human placenta].

An account is given of latest knowledge on the structure of the human placenta. Reference is made to the early stages of development as well as to maturation under both normal and pathological conditions. The paper is intended to contribute to better understanding of the pathogenesis of chronic placental insufficiency.

Chorionic Villi↗
PubMed1989

[Cholecystokinin-8-like immunoreactive structures in the olfactory bulb of the rat].

Using indirect immunocytochemical technique CCK-8-like immunoreactive neuronal somata and nerve fibers could be demonstrated in the olfactory tubercle of the rat. Cells found by immunostaining were compared with neuron types visible in Golgi-rapid-preparations. The existence of a CCK-containing efferent neuron type in the olfactory tubercle of the rat is suggested.

Animals↗
PubMed1989

[Morphometric studies of histologically classified chorionic villi of human placentas. 1. Placentas of eutrophic and hypotrophic full-term infants].

Occurrence of mature and immature chorionic villi was morphometrically analysed in 30 human placentae of children born on term. The following results were obtained from a method specially developed for surface determination of villus cross-section: The surface of mature villi (end or absorption villi) in children born on term with low birth weight was much smaller than that of immature villi. Total surfaces of mature and immature villi were almost equal in size as of the 25th percentile of child weight. The importance is underlined of a "transitional" class between hypotrophic and eutrophic children born on term, and a pattern of results is suggested.

Chorionic Villi↗
PubMed1989

[Morphometric studies of the histologically classified chorionic villi of human placentas].

The ratio between surfaces of mature and immature villi of 74 human placentae (17 from premature births and 57 from births on term) was morphometrically determined. The number of histologically classified chorionic villi was recorded, as well. The smallest surface and numbers of mature villi were recorded with significance from premature births and from hypotrophic newborns below the tenth weight percentile. The number of mature villi was found to grow continuously within a "transitional class" (tenth to 25th percentile) up to eutrophic newborns. This trend, however, was not recordable from immature villi. The diagnostic pattern recommended for routine examinations is based on numerical determination of so-called "mature normal villi".

Apgar Score↗
PubMed1988

[Not Available].

Explore the source record for details and available documents.

Food↗
PubMed1988

[Immunohistochemical demonstration of fibronectin in the human placenta].

The distribution pattern of fibronectin in the human placenta has been studied using the indirect immunoperoxidase (PAP) technique on formalin fixed paraffin embedded tissue samples. Fibronectin was demonstrated as intensely stained fibrillar or strand-like structures on the endothelial cells of blood vessels and on the amniotic epithelium. The most interesting fibronectin staining result, however, was found in the cytotrophoblast cells and in the bud-like structures of the syncytiotrophoblast. The results were discussed with regard to differentiation and proliferation in course of placental development.

Female↗
PubMed1987

Fluoride complexes of aluminium or beryllium act on G-proteins as reversibly bound analogues of the gamma phosphate of GTP.

Fluoride activation of G proteins requires the presence of aluminium or beryllium and it has been suggested that AIF4- acts as an analogue of the gamma-phosphate of GTP in the nucleotide site. We have investigated the action of AIF4- or of BeF3- on transducin (T), the G protein of the retinal rods, either indirectly through the activation of cGMP phosphodiesterase, or more directly through their effects on the conformation of transducin itself. In the presence of AIF4- or BeF3-, purified T alpha subunit of transducin activates purified cyclic GMP phosphodiesterase (PDE) in the absence of photoactivated rhodopsin. Activation is totally reversed by elution of fluoride or partially reversed by addition of excess T beta gamma. Activation requires that GDP or a suitable analogue be bound to T alpha: T alpha-GDP and T alpha-GDP alpha S are activable by fluorides, but not T alpha-GDP beta S, nor T alpha that has released its nucleotide upon binding to photoexcited rhodopsin. Analysis of previous works on other G proteins and with other nucleotide analogues confirm that in all cases fluoride activation requires that a GDP unsubstituted at its beta phosphate be bound in T alpha. By contrast with alumino-fluoride complexes, which can adopt various coordination geometries, all beryllium fluoride complexes are tetracoordinated, with a Be-F bond length of 1.55 A, and strictly isomorphous to a phosphate group. Our study confirms that fluoride activation of transducin results from a reversible binding of the metal-fluoride complex in the nucleotide site of T alpha, next to the beta phosphate of GDP, as an analogue of the gamma phosphate.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1987

The retinal phototransduction process: enzymatic cascade and regulation.

Among cellular systems performing the transduction of an external stimulus, phototransduction in vertebrate rod cells is a unique case which allows convergent approaches to electrophysiological, biophysical and biochemical analyses. The framework of the molecular processes involved in the corresponding enzymatic cascade is now elucidated and can be considered as a model for G protein mediated transductions. We present here the main features of this cascade, its amplification and regulation properties. The mode of stimulation by the aluminofluoride ion is particularly addressed.

Membrane Proteins↗
PubMed1987

The transducin cascade is involved in the light-induced structural changes observed by neutron diffraction on retinal rod outer segments.

Time-resolved neutron diffraction on retinal rod outer segments are performed to reinvestigate the origin of the light-induced structural change observed by Saibil et al. (Saibil, H., M. Chabre, and D. L. Worcester, 1976, Nature (Lond.), 262:266-270). Photoactivating rhodopsin triggers in rods a cascade of GTP-dependent and transducin-mediated reactions controlling cyclic-GMP hydrolysis. Infrared light-scattering studies (Kühn, H., N. Bennett, M. Michel-Villaz, and M. Chabre, 1981, Proc. Natl. Acad. Sci. USA, 78:6873-6877; Vuong, T. M., M. Chabre, and L. Stryer, 1984, Nature (Lond.), 311:659-661) demonstrated the existence of structural changes that correspond to this cascade rather than to rhodopsin photoactivation. We thus look for neutron diffraction changes of similar origins. With 1-min time resolution, intensity changes are observed mainly for orders 2 and 4. The illumination and GTP dependence of these changes indicates an involvement of transducin. Without GTP, they are linear with the amount of photoexcited rhodopsin, saturate at 10% photolysis, and thus correlate well with the light-scattering "binding signal." With GTP, light sensitivity is higher and saturation occurs below 0.5% photolysis, as for the "dissociation signal" of light scattering. In both cases, lattice compressions of 0.2-0.3% are observed. With 4-s time resolution the intensity change with GTP present precedes the lattice compression. The fast intensity change is probably due to the displacement of transducin alpha-subunits away from the disc membrane and the slower lattice shrinkage to an osmotic readjustment of the rod.

Animals↗