Deleted IgG1 and IgG2 H chains in a patient with an IgG subclass imbalance

The serum of a female patient studied over 7 months initially showed, in addition to normal residual IgG, two abnormal IgG proteins and in the last 3 months of the disease showed only one abnormal IgG protein. Gm typing and serological subclass determinations revealed an imbalance of allelic forms within the IgG1 subclass during the disease. The IgG2 level remained markedly elevated throughout the study. The two abnormal IgG-related proteins were devoid of light chains. The abnormal gamma cathodic immunoglobulin and the abnormal beta 2-immunoglobulin were Fc-like and covalently disulphide linked, with molecular weights of 60,000 daltons (N terminal, SER) and 72,000 daltons (N terminal, GLY) respectively. The first belonged to the IgG1 subclass and the second to the IgG2 subclass. No abnormal proteolytic activity was noted and plasma cells reacted with anti-gamma-chain antisera only. We hypothesize that the molecular defect leading to the deleted chains was an early event, preceding the differentiation into plasma cells which produced the two IgG1 and IgG2 deleted H chains.

Differential binding of IgG subclasses to enzyme-treated human lymphocytes

Human erythrocytes coated with each of the four human IgG subclasses were used to detect Fc gamma receptors on human peripheral blood lymphocytes (HPBL). Rosette formation was obtained only with erythrocytes coated with IgG3 (EA gamma 3). Neuraminidase treatment of HPBL induced rosette formation with EA gamma 1, EA gamma 2, and EA gamma 4 complexes. Pronase treatment also induced rosette formation to a lesser extent, but abolished EA gamma 3 rosetting. Trypsin treatment enhanced EA gamma 3 rosette formation. These phenomena occurred on both 'T' and 'non-T' lymphocytes. Erythrocytes coated with small quantities of IgG 3 did not form rosettes with HPBL. Neuraminidase treatment enhanced their binding, whereas pronase did not. These two phenomena occurred only on non-T lymphocytes. Rosette formation with EA gamma 1 was also obtained with lymphocytes stimulated in vitro with mitogens. After 2 days of culture, stimulated lymphocytes expressed receptors that were able to bind both EA gamma 1 and EA gamma 3 complexes. These results suggest the existence of cryptic receptors for IgG1, IgG2, and IgG4 that could be disclosed by neuraminidase and pronase treatment and exposed on stimulated lymphocytes. A hypothesis of one or several Fc gamma receptors is suggested.

Interactions of the third component of human complement (C3) with tumour cells: evidence for presence of C3b acceptor sites and direct activation of C3 by tumour cells

The interaction of C3 with different tumour cell lines was investigated. Our results indicated that nearly all the cell lines had C3b acceptors on their membranes. The binding of C3b was visualized by the detection of this protein on the cell surface with fluoresceinated anti-C3c serum. The involvement of proteases in the activation of C3 was demonstrated: complement-membrane fluorescence occurred in the presence of EDTA but was completely abolished with epsilon-aminocaproic acid. Experiments performed with purified C3 led to the conclusion that the protease activity might be the initial event for the activation of the alternative pathway by tumour cells.

Evidence for alpha-1-acid glycoprotein populations of different pI values after concanavalin A affinity chromatography. Study of their evolution during inflammation in man

Isoelectric focusing in polyacrylamide gel was used to reveal the two alpha 1-acid glycoprotein populations separated by affinity chromatography on Con A-Sepharose from human purified alpha 1-acid glycoprotein, whole normal serum and sera from patients undergoing an acute inflammatory process. The concanavalin A non-reactive peak had a lower isoelectric point than did the concanavalin A reactive peak. Moreover, crossed immunoaffinity electrophoresis with free concanavalin A revealed three alpha 1-acid glycoprotein populations (concanavalin A reactive, weakly and non-reactive). A significant difference was observed between the patterns of normal and of inflammatory sera, since the concanavalin A reactive fraction was enhanced during the inflammatory process. These results suggest a variation in relative ratios of the different types of peripheral oligosaccharide branches in the alpha 1-acid glycoprotein populations.

A redox function for the Calpha2 domain of IgA immunoglobulin

IgA1 populations were reduced over a range of dithiothreitol concentrations and the products were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and peptide mapping. The study showed that IgA was more resistant to reduction than other immunoglobulin classes (IgG, IgM). SDS-polyacrylamide gel electrophoresis showed that intersubunit bond and H-L bond were the most labile disulfide in polymeric and monomeric IgA, respectively. Peptide mapping revealed that the itrachain disulfide of the C alpha 2 domain was more or equally sensitive to the reduction than H-L and intersubunit bonds. Electrochemical experiments demonstrated that this bond had redox properties and the possibility involving disulfide exchange is discussed.

Effect of sialic acid removal on human low density lipoprotein catabolism in vivo

This study was undertaken to determine whether sialic acid removal alters the catabolism of low density lipoprotein in humans. Human low density lipoproteins labeled in vitro with 125I were incubated in the presence (termed desialylated) or absence (sialylated) of neuraminidase. The treatment with neuraminidase from Clostridium perfringens removed 90% of the sialic acid residues which did not change the chemical composition of the lipoproteins. Sialylated or desialylated LDL were injected intravenously into normal human subjects. The mathematical analysis of the plasma radioactivity decay curves (followed for 220 h) of desialylated low density lipoproteins, when compared with sialylated LDL, showed a shorter mean transit time (51 h vs 60 h), a 52% faster metabolic catabolic rate and an increased volume of distribution. The data are consistent with a proposed metabolism of low density lipoproteins: in humans, desialylation appears to accelerate the first step of the low density lipoprotein conversion but not to alter its final catabolism.

Experimental infection of calves with bovine respiratory syncytial virus (Quebec strain)

An experiment was designed to evaluate the clinical, haematological, viral and serological aspects of bovine respiratory syncytial virus infection in calves. Eleven calves were inoculated intranasally with bovine respiratory syncytial virus (Quebec strain) in aerosol. Clinical, haemotological and serological responses of the calves and virus shedding were monitored. The experimentally infected animals manifested moderate to severe signs of respiratory disease. The parameters used to evaluate the severity of the disease included ocular discharge, conjunctivitis, lung sounds, nasal discharge, pyrexia and leukopenia. The animals were scored accordingly (scale infected 70.8-148.5, control 22-29.3). Highest disease scores were observed between day 6-9 after infection. Virological and serological assessment demonstrated that the observed clinical picture was due to bovine respiratory syncytial virus infection.

[Augmentation of HL-A A9 antigen in malignant melanoma, principally in metastatic or recurrent forms. Apropos of 105 cases of melanoma of which 34 were serious forms]

HLA-A and B phenotypes of 105 patients suffering from malignant melanomas were determined, with special regard for metastatic form or relapse. A highly significant increase of the HLA-A9 antigen is seen (X2 = 17.47); such data had already been shown by van Wijek [2], but other authors did not find this abnormality when studying melanomas whose histologic form was not specified.

Preparation of an R3 reagent (serum depleted of the third component of human complement (C3)) by immunoadsorption. Application to the hemolytic assay of human C3

We have devised a simple one-step preparation of C3 depleted serum (R3). Fresh normal human serum, with complement activation inhibitors, was depleted of C3 by affinity chromatography on a Sepharose anti-C3c. To prevent non-specific interactions, a high ionic strength buffer containing saccharose was used. Immunochemical analysis and complement activity assays demonstrate that this C3 depleted serum is a suitable R3 reagent. This R3 reagent has been used successfully for titration of hemolytic activity of C3 in normal and abnormal sera. Two simple, specific and sensitive assays are described.

Evidence that an autoantibody of IgG3 subclass against C3b discloses a C3 Nef activity in a pateint with partial lipodystrophy and glomerulonephritis

Immunoglobulins of IgG3 subclass were purified from the serum of a patient with partial lipodystrophy and glomerulonephritis. The immunochemical data clearly showed that the immunoglobulins were directed against newly-formed determinants on C3 molecule when activation of complement occurred. This autoantibody property was related to the C3 nephritis factor activity present in the serum of the patient. Furthermore, this serum was unable to destroy cell bound C3b. This result suggested that this patient would presented a deficiency of C3b inactivation system.

[General facts on mastocytoma in the dog. Apropos of the first Tunisian case]

After anatomo-pathologic, épidemiologic and etiopathogenic description of canine Mast-cell tumor, the authors insist on the importance of this neoplasm in comparative pathology. Such animal model observation can be eventually used both in cancer Research and in allergo-dermatology.

The effect of fasting on the interactions between human low density lipoproteins and calcium, heparin and chondroitin sulfate

Fasting modified the in vitro interactions between low density lipoproteins (LDL) and glycosaminoglycans. Calcium had a potentiating effect on these interactions. LDL-calcium-heparin interaction was dependent on the presence of sialic acid whereas LDL-calcium-chondroitin sulfate interaction was inversely correlated with cholesterol content.

A study of the breakdown of the third component of human complement (C3)

This paper reports the description of fragments of human C3, purified from aged sera. Sera were incubated at different temperatures (4 degrees, 20 degrees and 37 degrees C) for 8 days or more. At 4 degrees C, the major isolated fragment was C3b which showed a heterogeneity of structure. Under reducing conditions, it liberated a 40,000 dalton fragment which reacted against an anti-C3d and which we called "C3d-like". At 20 degrees C, C3b was partially destroyed to yield the C3c- and C3d-fragments. At 37 degrees C, C3d and C3c were obtained. C3c presented a structural heterogeneity. It was made either of two chains of 75,000 daltons or of three chains with 75,000, 38,000 and 31,000 dalton MW. The comparison of these fragments with those obtained by tryptic hydrolysis led us to propose a pathway to the degradation of C3 and to bring some informations about the structure of this molecule.

Relationship between the carbohydrate content of apoproteins of VLDL, IDL, and LDL and the plasma level of these lipoproteins in man. Short dietary effect

A 1,500 Cal test meal was used to study in man the apoprotein B-carbohydrate content and composition of VLDL, IDL and LDL in relation to the variation of plasma lipids and lipoproteins and the VLDL-apoprotein composition. Three essential facts emerge from the study: (1) the mirror image (inverse significant correlation) between VLDL-apo B plasma concentration and N-acetylglucosamine content of apo B; (2) a reduction in total carbohydate concentration of VLDL- and LDL-apo B, 2--4 h after the test meal and a trend to a reduction in the mannose content; (3) a significant correlation between sialic acid and apoprotein B concentration in plasma LDL during fasting. The effect of diet and subsequent fasting on carbohydrates of lipoproteins and the consequence of such changes on lipoprotein uptake are briefly discussed.

[Ocular symptoms in pituitary adenomas (author's transl)]

The study of 85 patients suffering from pituitary adenoma, amongst which 56 with a visual failure, allowed to show: 1) The importance of the functional loss a revealing sign of the disease (50% cases). 2) The importance of the ophthalmological examination as a diagnostic argument. The latter, however, needs an extremely methodical examination of the visual fields. The combinated use of the Goldman Perimeter, and the Amsler schemes gave us satisfactory results: 87.5% of patent bitemporal hemianopsiae. It has been useful, in several cases to enhance these methodes by using coloured indexes. All of the patients underwent surgery, with complementary radiotherapy. The functional recovery quality has been shown, in the majority of the cases, to be proportionnal to the operation precocity in relation to the first functional symptoms.

Selective deficiencies in complement component : a family with hereditary C2 deficiency

We report herein a new case of C2 deficiency in a patient with systemic lupus. The subject and one of her brothers, who shows no clinical manifestations, are hymozygous C2 deficient. All other family members are heterozygous for the C2 deficiency. Gene for C2 deficiency (C2d) was shown to be inherited with HLA-A9, B7/Bfs and HLA-A10, B27/Bfs haplotypes. This association has not previously been described.

[Comparative study of cysteine peptides of monomers and polymers of IgA]

The cysteinyl peptides of monomeric and polymeric IgA were studied by comparative autoradiography. Autoradiographies of polymeric IgA (containing or lacking J chain) showed an extra cysteinyl peptide which was never found in the monomeric forms. A similar peptide was obtained when reduced IgA was cleaved by BrCN. The possible identity of this fragment is discussed.

Evaluation of a rapid method of determination of plasma fibrinogen in swine

An evaluation was made of a rapid semiautomated method for determining fibrinogen level in swine plasma. This method, referred to as thrombin time method or fibrometer method, is based on the principle that when thrombin is added to suitably diluted plasma, the time of clotting is linearly related to the fibrinogen concentration. The linear regression model for the standard curve prepared using swine plasma had an r value of 0.998. A comparison between the fibrometer and the Grannis methods done on 189 swine plasma samples showed good correlation between these two mehtods (r value 0.847). It was concluded that although the fibrometer method may not be as precise as the Grannis method, it would still be acceptable for clinical use in swine.

Studies on vitamin E and selenium deficiency in young pigs. I. Hematological and biochemical changes

Pigs which were deficient in vitamin E and/or selenium had the following parameters weekly determined from six to 13 weeks of age: Packed cell volume, hemoglobin concentration, red cell and white cell counts, red cell indices, reticulocyte count, serum iron, serum total iron binding capacity, myeloid: erythroid ratio, serum glutamic-oxaloacetic transaminase and creatine phosphokinase activities and body weight. Except for the myeloid:erythroid ratio and serum creatine phosphokinase activity, these parameters were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency of both. The myeloid:erythroid ratio was increased (p less than 0.01) in association with selenium deficiency, which tends to indicate decreased erythropoiesis but was not reflected in the peripheral red cell picture. Evidence of dyserythropoiesis was not found to be a significant feature in serial bone marrow aspiration biopsies of vitamin E and/or selenium deficient pigs. Even if the serum glutamic-oxaloacetic transaminase activities were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency in both as compared to replete animals, a few animals, especially in the group deficient in both vitamin E and selenium, presented quite marked transient increases of serum glutamic-oxaloacetic transaminase activity which was interpreted to reflect the occurrence of acute episodes of hepatosis dietetica. Serum creatine phosphokinase activities were found to be increased in association with vitamin E deficiency (p less than 0.01), selenium deficiency (less than 0.05) and the interaction was also significant (p less than 0.01). It was concluded that the serum creatine phosphokinase activity increases reflect the occurrence of subclinical muscular dystrophy and that vitamin E and selenium deficiencies have marked additive effects in the induction of skeletal muscular dystrophy.

[Two new peptic fragments of human IgA: F(abc)'2Alpha and [F(abc)'2]2alpha (author's transl)]

These experiments were undertaken to study the nature of the fragments produced by pepsin digestion of seric IgA. We describe a new fragment with a MW of 140,000 daltons. This fragment, the first produced during pepsin hydrolysis of monomeric IgA, corresponds to an IgA molecule which has lost its CH3 domain. We propose to call this fragment F(abc)'2alpha. It is gradually digested and transformed into an F(ab)'2alpha fragment. When polymeric IgA are digested, an extra fragment with a MW of 290,000 daltons is produced, which has kept its polymeric structure. It corresponds to a covalent [F(abc)'2]2alpha fragment. These findings suggest that there is an intersubunit disulfide bridge in the Calpha2 domain. These results also indicate that polymeric IgA proteins are more resistant to pepsin digestion than monomeric IgA proteins.

Studies on vitamin E and selenium deficiency in young pigs. III. Effect on kinetics of erythrocyte production and destruction

The effect of vitamin E and/or selenium deficiency on the kinetics of erythrocyte production and destruction has been investigated in swine. The plasma iron turnover rate, 59Fe incorporation into newly formed red cells as well as the 51Cr apparent red cell half-life, were not found to be significantly affected by either vitamin E deficiency, selenium deficiency or deficiency of both, as compared to replete animals. The results of this study suggest that vitamin E is not a limiting factor for normal erythropoiesis in young growing pigs. Erythropoiesis appeared, however, to be slightly decreased in selenium deficient pigs and will need to be further investigated.

Studies on vitamin E and selenium deficiency in young pigs. IV. Effect on coagulation system

An evaluation of the coagulation system has been conducted in vitamin E and/or selenium deficient swine. The partial thromboplastin time, plasma fibrinogen concentration, platelet lipid peroxides, as well as the fibrinogen/fibrin degradation products were not found to be significantly affected by either vitamin E deficiency, selenium deficiency, or deficiency of both. With selenium deficiency, the prothrombin time was shortened (p less than 0.05). The platelet count and platelet turnover were greatly decreased by both vitamin E (p less than 0.001) and selenium deficiency (p less than 0.005). Further-more, the survival of platelets labelled with 75Se-selenomethionine and the per cent isotope incorporated into platelets were reduced (p less than 0.05 and p less than 0.005) in association with vitamin E deficiency, but not with selenium deficiency. These results were interpreted as evidence of a platelet production defect and possibly a platelet function defect in vitamin E deficient animals. Selenium deficiency were also associated with decreased (p less than 0.05) survival of fibrinogen labelled with 75Se-selenomethionine and increased (p less than 0.05) turnover of fibrinogen. From these fibrinogen kinetic findings, it was considered that chronic low grade disseminated intravascular coagulation possibly occurs in selenium deficient animals, probably in relation to the development of hepatosis dietetica or widespread microvascular damage. However, other possibilities such as increased fibrinogenolysis in relation with hepatosis dietetica or an intrinsic fibrinogen defect due to selenium deficiency also need to be taken into consideration and have not been ruled out in the present study.

Studies on vitamin E and selenium deficiency in young pigs. II. The hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium status

The usefulness of the hydrogen peroxide hemolysis test and the measure of red cell lipid peroxides as indices of vitamin E and selenium deficiency in swine has been evaluated. Results indicated that although the hydrogen peroxide hemolysis test may be of some indication of the vitamin E status, it is not a reliable index of vitamin E deficiency in swine, at least on an individual basis. In contrast, the measure of red cell lipid peroxides can be considered a reliable test for vitamin E deficiency in swine. The hydrogen peroxide hemolysis test and the red cell lipid peroxides were not significantly affected by selenium deficiency.

Septation deficiency and phosphilipid perturbation in Escherichia coli genetically constitutive for the beta oxidation pathway

Mutants of Escherichia coli defective in the regulation of the fatty acids beta oxidation pathway show an ultrastructural deficiency in septum formation at high growth rate. Several independent pairs of parent and mutant strains have been analyzed biochemically. Each parent strain displays a well-defined pattern of cellular phospholipids, which varies with the growth conditions. High ratios of phosphatidylglycerol to cardiolipin characterize fast-growth conditions. None of the mutant strains, although they grow in mass nearly as rapidly as their respective parents, can reach these high ratios. The beta oxidation pathway regulatory mutation leads to an increased turnover of the glycerol moieties of these phospholipids in the inner as well as in the outer cell membrane.

Localization of J-chain and interchain disulfide bonds in a human F(c)5mu-like fragment

The inter H-H cysteinyl peptides and the localization of the J-chain were studied in a human F(c)5mu-like fragment. The latter was found to be built up by non-covalent association of molecular forms of 140 000, 95 000 and 70 000 dalton subunits. The trimeric, dimeric and monomeric forms were obtained from gradual reduction by dithiothreitol of the major component of 140 000 daltons, thus confirming the tetrameric nature of this subunit. The latter was found to result from the association of both components of the 70 000 dalton subunit, with the participation of the inter H-H subunit bridge. Structural analysis of the labelled peptides obtained by partial reduction and alkylation showed the presence of the intersubunit disulfide bridge and of the inter heavy-heavy chain bridge of the C-terminal region, and the absence of the heavy-heavy chain bridge of the hinge region. The sequence of these peptides is identical to the sequences of the corresponding peptides of normal mmu-chains. The J-chain, which was covalently linked to this F(c)5mu-like fragment, was found to be predominantly associated within the 95 000 dalton subunit. The results showed that the J-chain was linked in the protein as a "clasp" within a single subunit and not between two subunits.

Hormones and the Control of Reproduction in Aquaculture

The role of hormones and compounds probably intervening by hormonal mechanisms in the reproduction of teleosts are considered. First of all, the fundamental part played by the pituitary and its gonadotropic hormone or hormones in the control of reproduction are stressed by discussing problems which are still outstanding. The zoological specificity of gonadotropic hormones, the mechanism of their action, and the possibilities of using mammalian hormones are examined. The intervention of pituitary hormones other than gonadotropins is then considered. The actions of organs, tissues, and hormones secreted before the pituitary (hypothalamus, epiphysis) and that of the same formations and hormones beyond the pituitary, whose intervention is certain or under discussion (sexual steroids, hormones of the interrenal and the chromaffin tissue, ultimobranchial body and calcitonin, thyroid, urophysis) are discussed. Mention is also made of the prostaglandins.The endocrine control of reproductive behavior and the intervention of pheromones in the reproduction of teleosts are discussed. Then the effects in reproduction of certain extrabiological substances are briefly examined (for example, clomiphene citrate, copper acetate, asphalt, petrichor, methallibure).Final emphasis is given to the importance of ecophysiological studies in the endocrine control of reproduction, which should lead to much more natural and less costly techniques by applying data presently at our disposal, regarding hormonal control of reproductive function.

[The historic role of insulin in the physiopathology of the metabolic complications from pancreatic diabetes. Therapeutic implications for somatostatin]

Possible ways in which somatostatin may influence the secretion of glucagon and insulin are discussed. The fact that it is possible to maintain normal blood glucose levels in pancreatectomised animals and in juvenile diabetics totally lacking in insulin, solely by the administration of somatostatin, is emphasised.