Biomedical subjects
Publications and source records attributed to L Hartmann.
It was known that with dietary and hormonal conditions the level of hepatic L pyruvate kinase (LPK) varied greatly. By immunochemical method we demonstrate in vitro insulinodependence of MPK in isolated hepatocytes. In hepatocytes of fasted Rats this effect was time and concentration dependent, but proinsulin was ineffective.
An analysis of cell membrane material present in circulating immune complexes isolated from normal human sera by precipitation with polyethylene glycol (PEG) has been performed with the platelet alloantigen PlA1 and rhesus antigen used as markers. PEG precipitates obtained from the sera of subjects of known PlA1 and rhesus phenotype were resuspended in buffer and analyzed as representative of circulating immune complexes (CIC). The consumption of anti-PlA1 serum by CIC was determined by immunofluorescence and by inhibition of sodium 51chromate release from PlA1-positive target platelets. With these two techniques, PlA1 alloantigen activity was detected in CIC. This finding suggests that at least some of the cell membrane material present in CIC is derived from platelets.
In healthy human livers, L pyruvate kinase (L PK) was detected by immunofluorescence and double labelling in hepatocytes and M PK was detected in bile duct epithelial cells. Numerous associations between isoenzyme type and hepatological lesion were observed. In 10 cases of ethanolic cirrhosis, L and M PK were simultaneously observed in the hepatocytes of regenerative nodules, as they were in biliary neoductules; fibrotic regions were L and M PK negative and the hepatocytes in the anastomosing plate system were almost exclusively L PK positive, as in normal subjects. In 12 hepatocarcinomas, cancer cells had a double L and M specificity with variations in the intensity of the M isoenzyme, while the stroma reaction was L and M negative. In five hepatoblastomas, the simultaneous presence of L and M PK was also observed, but the consistently marked intensity of M PK argues in favour of the embryonic nature of this type of cancer. The results suggest that mature, highly differentiated cells exclusively and specifically synthesize one isoenzyme. A double specificity in pathology reflects the dysfunctional state of the hepatic and biliary epithelial cells or a dedifferentiated state which may terminate with the appearance of a cancer.
Using immunofluorescence and double-labelled antisera L and M pyruvate kinase (PK), we show that PK is localized in hepatocyte cytoplasm. The response is modulated by different dietary and hormonal conditions. In physiological conditions, only L PK is noted: slight with normal diet (or 35 micrograms of glucagon) and non-existent with starvation (or 350 micrograms of glucagon). L PK fluorescence is maximal after a carbohydrate-rich diet. In experimental or genetic (Zucker rat) hyperinsulinemia, hepatocytes are both L PK and M PK positive. After partial hepatectomy, this double specificity is found between 48 h and the 7th day. The decrease of PK fluorescence after starvation or glucagon concerns the L PK form of the enzyme. With exo- or endogenous insulin, the increase of PK (as insulinemia assays from Zucker rats or after partial hepatectomy confirm) is essentially due to the presence of M PK in hepatocytes.
By immunofluorescence and double labelled anti sera L and M pyruvate kinase, there is a double localization of isozymes. It is detected in basal state, in vitro, in isolated hepatocyte, in vivo in experimental or genetic (Zucker rat) hyperinsulinemia or in regenerating liver following partial hepatectomy. It is found in hepatology, in regenerative nodule of cirrhosis and in cancerous cells of liver. This double presence of L and MPK tallies with a specific double hormonodependence: induction of MPK by insulin, and inhibition of LPK by glucagon.
The previous demonstration of an association between the collagen-like region of C1q (subcomponent of the first component of complement) and human platelets and of the inhibitory properties of C1q on platelet adhesion and aggregation to or by collagen has led us to consider the first component of complement as a possible modulator of the platelet-collagen interaction. Since collagen represents a major component of the vessel wall, the modification of C1 could play a role in the development of thrombosis. We have therefore studied two patients with abnormalities of complement (low or undetectable C1, C4, C2 and deficiency in C1 inhibitor) who presented with acquired angioneurotic oedema. Both patients had a history of multiple episodes of arterial and/or venous thrombosis. Platelet associated C1q was decreased or undetectable, and this condition was associated with a specific increase of collagen induced aggregation thereby suggesting a possible mechanism for the recurrent thromboembolic episodes.
Coagulation contact factors were studied in 9 patients with hereditary angioneurotic oedema. After storage of the plasma at O degrees C for 20 hours, activation of prekallikrein and factor VII, together with prekallikrein consumption, were observed. The cold activation, due to deficiency of C1 esterase inhibitor, was not suppressed by polybren in vitro (factor XII activation inhibitor) but was prevented by aprotinins (kallikrein inhibitors). These findings would suggest that patients with hereditary angioneurotic oedema should be investigated for prekallikrein consumption and should be treated with aprotinin as soon as the attack begins.
Urinary melatonin variation in humans were demonstrated to be a function of age. A radioimmunological assay was used. The values obtained, expressed as nmol x 24 h-1 x kg-1, progressively decreased from birth onwards, with a more accentuated and momentary inflection at the moment of the genital crisis in newborns and at puberty. The results obtained concern only melatonin and not its metabolites, as a result of the high specificity of the antibodies employed.
Proteins isolated from ribosomal subunits of various mammalian cels were analysed comparatively by two different methods: a two-dimensional polyacrylamide gel electrophoresis system and a recently described two-dimensional immunoelectrophoresis technique. For this purpose, antisera were raised in rabbits against the total mixture of ribosomal proteins from murine cells. These sera were characterized by ring-test, double immunodiffusion and two-dimensional immunoelectrophoresis. They were shown to contain antibodies to a large number of ribosomal proteins. Immunoelectrophoretic analysis of 60S and 40S subunit proteins from rabbit, lamb, canine and human cells using anti-murine sera revealed a striking conservation of their antigenic properties. These results corroborated those obtained by two-dimensional polyacrylamide gel electrophoresis.
The distribution of pyruvate kinase (ATP pyruvate phosphotransferase, EC 2.7.1.40) in the nervous system has been studied by both immunofluorescence and a histochemical procedure using nitro blue tetrazolium. The localization in various parts of rat central nervous system in situ, cerebellar and cerebral cortex, was compared to that found in vitro in cultures of cerebellum, spinal ganglia, cerebral astrocytes, and skin fibroblasts. (1) Pyruvate kinase was found predominantly in the cytoplasm of neuronal cell bodies. (2) Large neurons were better visualized than small ones. (3) No glial localization was clearly demonstrated in situ, although this does not rule out the presence of some M1 pyruvate kinase. (4) Regions expected to be rich in nerve terminals, such as the cerebellar glomeruli or the cerebellar molecular layer, showed intense staining even when the cell bodies themselves were negative. This was expected, owing to the previous demonstration of the presence of M1 pyruvate kinase in nerve ending by subcellular fractionation methods. (5) The localization was similar in situ and in tissue culture, except that nerve processes were better seen in the latter and astrocytes were sometimes stained in vitro. (6) Variation in intensity of staining was observed in similar cell types in the same section or in the same culture. This could represent different metabolic or functional or maturational states.
Explore the source record for details and available documents.
Antisera were raised in the rabbit against human Tamm-Horsfall protein (THP) and erythrocyte ghosts. They were purified and exhausted with serumalbumin. Using a radioimmunoassay, antisera against THP allowed to detect in erythrocyte ghosts 41 ng of a reaction material per mg membrane protein. Ouchterlony double diffusion technique showed a similar corss-reaction and, conversely, a cross-reaction between THP and antisera to erythrocyte ghosts. These data support the view that red cell membrane contains a compound related to THP.
The carbohydrate composition of 18 monoclonal IgM (Waldenström macroglobulinemia) was determined by gas-liquid chromatography. Two populations occurred with mean sugar contents of 7.3% (12 IgM and 10% (6 IgM). A value of 7.2% was obtained for 8 IgM prepared from 8 normal sera. On the basis of mean molar ratios established for each monosaccharide residue, structural models for oligosaccharide units are proposed. The number of complex glycan chains (N-acetyllactosaminic type) is higher in the 10% population, which would correspond to IgM with a mean sedimentation constant of 18.3So20, W. On the other hand, the 7.3% population has a lower content of "mature" chains and its sedimentation constant would be inferior: 17S)20, W.
A total increase of blood complement components, particularly C4, is found in subjects with familial Mediterranean fever both before and after colchicine therapy. This effect differs from the serum haptoglobin and orosomucoïd concentration decreases detected after identical therapy, confering diagnostic value to this inflammatory syndrome. This could be of both hepatic and extrahepatic origin. For the latter, it is possible that up take of circulating monocytes, macrophage precursors, by the connective tissue of the serum sub-mesothelial layer is responsible for the lesion.
The M1 pyruvate kinase has been localized in macroneuron's cytoplasm of nervous tissue of adult Rat, in situ as well as in tissue culture. Three methods have been used: histoenzymology, immunoenzymology and immunofluorescence, combined with Nomarski optics. This enzymatic localization may suggest a metabolic or differenciated fonctionnal state of the nerve cell.
Using two-dimensional immuno-electrophoresis to study a morphological abnormality of the alpha 2-neuramino-glycoprotein (alpha 2-NGP) we have been able to observe allelic exclusion in patients afflicted by hereditary angioneurotic oedema [1]. With the aid of two-dimensional immuno-affino-electrophoresis, we have been able to show that in some cases, there exists a double abnormality of alpha 2-NGP associating a deficiency in post translating glycosylation with a loss of the inhibitory function of the C1 esterase.
Anti-melatonin antibodies of high titer and good sensitivity were obtained by coupling melatonin to bovine serum albumin with formaldehyde and by immunizing rabbits with multifocal intra-dermal injections. A systematic study of cross-reactions with 14 compounds (indole, aromatic and imidazole derivatives) showed that the antibody had a high specificity for melatonin, low reactivities with 6-hydroxymelatonin and N-acetylserotonin and no detectable reactivity with 12 other derivatives. The roles of the indole nucleus and the side chain in the determination of the antigenic properties of the molecule are discussed.
We have studied the effect of insulin upon the accumulation of glucose carbon into the intima-media and the adventitia of rat aorta following in vitro exposure by adding insulin to the incubation medium, and in vivo exposure by producing relative hyperinsulinemia during life and subsequently incubating excised tissue in a medium containing no insulin. Hyperinsulinemia in vivo was either (1) endogenous--following 1.5-2 hr of refeeding after a 48-hr fast--or (2) exogenous--following an i.v. injection of insulin. For adventitia, a significant stimulation was found after both in vitro (+ 53%, p < 0.001) and in vivo exposure to insulin (+ 96%, p < 0.01 with endogenous insulin; + 75%, p < 0.05 with a dosage of 2 U/kg of exogenous insulin). For intima-media, the stimulation was weak and insignificant after in vitro exposure (+ 11%, p > 0.30), but became important and significant after in vivo exposure to insulin (+ 100%, p < 0.001 with endogenous insulin; + 50%, p < 0.05 with a dosage of 0.5 U/kg and + 49%, p < 0.05 with a dosage of 2 U/kg of exogenous insulin). For the in vivo exposure experiments, we found a significant linear correlation (r = 0.611, p < 0.005) between plasma insulin concentrations and glucose carbon accumulations into intima-medias of control and refed rats. These results establish the insulin sensitivity of the adventitia and show a sensitivity of intima-media only to in vivo insulin exposure. These different behaviors of intima-media in vivo and in vitro may have a hemodynamic basis.