[Hemoglobin alpha chain isoelectric point modification under the action of urea, sodium cyanate, succinic anhydride or diethylene triamine pentaacetic acid anhydride]. / Modifications du point isoélectrique de la chaine-alpha de l'hémoglobine sous l'action de l'urée, du cyanate de sodium, de l'anhydride succinique ou de l'anhydride diéthylène triamine pentaacétique.

A monomeric protein, the hemoglobin alpha chain, was used to compare four protocols for conjugation with diethylene triamine pentaacetic (DTPA) anhydride. Carbamylation and succinylation were also performed. The isoelectric point (pI) was 7.7 for the native protein versus only 5.5 to 7.3 for the five carbamylated derivatives and 4.0 to 7.0 for the six succinylated derivatives. With carbamylation or succinylation, increasing the molar ratio (agent/protein) was associated with a gradual downward pI shift producing trains of bands. This phenomenon did not occur with DTPA conjugation, whose results varied with the method used; only one derivate (pI 6.7) was produced by all four methods, and multiple fine bands with pH values in the vicinity of 3.6 were seen. For the protein, the pI shift varied with the number of groups inserted on the primary amine residues. Also, the shift was larger if the inserted groups carried electrically-charged moieties.

Dose optimization of gallium chloride, orally administered, in combination with platinum compounds.

An individual dose adaptation for cisplatin (CDDP), etoposide and gallium chloride (GaCl3) was proposed to improve the efficacy of this combination chemotherapy and avoid its toxicity. A clinical study was performed in 28 non small cell lung cancer patients, to verify this hypothesis. CDDP and etoposide were administered as continuous infusions every 3 weeks and GaCl3 orally during and between the CDDP-etoposide sequential infusions. CDDP doses were adjusted to achieve, during each 5 day infusion, an area under the total plasma platinum concentrations versus time curve (AUC Pt 0-120) ranging between 80,000 and 100,000 micrograms/l.h. Etoposide dosages were 120 mg/24 h during days 1-3 of the CDDP infusion. GaCl3 dosages were adjusted to obtain plasma gallium (Ga) concentrations ranging between 200 and 400 micrograms/l. The proposed methods of adaptation were successful from a pharmacokinetic point of view as AUC Pt 0-120 were respectively 81351 +/- 4788, 88268 +/- 8451 and 88331 +/- 8778 micrograms/l.h during the first 3 courses, and plasma Ga concentrations, determined during the 2nd and 3rd CDDP courses, 16 hours after the beginning of the CDDP infusion, were respectively 264 +/- 127 and 313 +/- 186 micrograms/l. However, these results were not pharmacodynamically successful and the therapeutic window was not confirmed. Past clinical trials with GaCl3 will be reviewed, as well as the factors which modify the pharmacokinetics or the pharmacodynamic effects of CDDP and GaCl3. From this review, an optimal dosage of 400 mg GaCl3 could be proposed to potentiate a combination chemotherapy with a platinum compound. The target AUC of the platinum compound should be the AUC avoiding its cumulative toxicity.

[Changes in isoelectric points of the monoclonal antibody OC 125 during indium 111 radiolabeling]. / Modifications des points isoélectriques de l'anticorps monoclonal OC 125 lors de son radiomarquage par l'indium 111.

Isoelectrofocusing analysis of the murine monoclonal antibody OC 125 (IgG1) revealed four bands at pI (6.6-7.2). After pepsin digestion, f(ab')2 pIs were increased by 0.6 pH units and two additional bands were visible. DTPA conjugation decreased pI (by up to -2 units) and increased heterogeneity (10 bands or more). With In3+ at saturation level, the conjugate was slightly modified. Autoradiography revealed pI heterogeneity of OC 125-f(ab')2-DTPA-In-111. These data show that isoelectrofocusing enables accurate monitoring of monoclonal antibody changes during In-111 labeling.

[Urinary iodide determination by X-ray fluorescence]. / Dosage des iodures urinaires par fluorescence X.

Urinary iodide measurement has been carried out by X-ray-fluorescence, either directly on urinary solution, or after matrix concentration. Proportionality between emitted XK alpha rays of iodine and iodide mass in standards has been observed on a large scale, ranging up to 400 micrograms. With an exciting-1.11 GBq (241(95) Am)-radioactive source, 0.44 microgram are detected for solid matrix, and 0.9 microgram/ml for iodide in solution for 10 mn measuring time. So direct measurement on solution can be applied only to high excreted iodide. For normal range iodide determination is performed after anionic resin concentration (on 100 ml or 200 ml). For tracing, Na I131 is employed. The binding ratio is strongly depending on flow, resin weight, and associate urinary anionic components. On 20 healthy subjects, normal range value is 53 +/- 22 micrograms/l (m +/- s.d.). Comparative study with an electrochemical method showed fluorescence iodide values are lower than the former. The proposed method is very simple, one or two steps (function of iodide content). As no interfered Rx has been observed in the Rx iodide region, the authors can ascertain that accurate values are observed by X-ray fluorescence. In case of high iodide content, this methods allows to distinguish urinary iodide versus total urinary iodine, when performing solution and matrix concentration studies on the urinary batch.

F.p.l.c. analysis of the leakage products of proteins crosslinked on Dacron vascular prostheses.

The haemocompatibility of vascular, Dacron prostheses was improved by coating with albumin and/or collagen crosslinked with glutaraldehyde (GTA) or carbodiimide (CDI). F.p.l.c. (fast protein liquid chromatography) analysis of the products desorbed from polymeric matrices incubated in physiological conditions for periods extended up to 10 d did not detect the monomers or polymers of collagen and albumin but small amounts of degradation products, the molecular weights of which were less than 45,000, thus minimizing an eventual immunogenic response after implantation. However GTA and CDI matrices required extensive washing to neutralize the cytotoxic effect of GTA and achieve the release of CDI from protein complexes.

[Metallic trace elements--A1, Cd, Cu, Fe--in solutions of 111InCl3: determination by flameless atomic absorption and results in 111In-radiolabeling of monoclonal antibodies]. / Traces métalliques--A1, Cd, Cu, Fe--dans les solutions de 111InCl3: dosage par absorption atomique sans flamme et conséquences pour le radiomarquage par 111In des anticorps monoclonaux.

Determination of trace elements in 111InCl3 solution have been carried out by flameless atomic absorption spectrometry. Five successive batches from three European companies have been analysed. The means of measured values range from 4560 to 6930 micrograms L-1 for aluminium, 131 to 874 for cadmium, 49 to 300 for copper, 387 to 698 for iron. Using two molar ration indexes, trivalent metallic traces have been compared to theoretical 111In content. The trace elements largely exceed radioactive material. As Fe and In have similar chemical properties, it results in low specific activity of radioactive complex when labeling monoclonal antibodies by 111In. Using a mathematical model, a detrimental effect of Fe trace levels has been studied.

Textile arterial prostheses: is water permeability equivalent to porosity?

Porosity and water permeability are two distinct terms that describe different characteristics of vascular prostheses. The porosity is a measure of the void fraction within the prosthesis wall and is believed to give a rough prediction of the capacity of the graft to anchor newly formed surrounding tissue after implantation, whereas the water permeability indicates the rate at which water can flow through the prosthesis wall and, when measured under physiological pressure conditions, provides the surgeon with information about the need for preclotting prior to implantation. The literature has not always clearly distinguished between these two terms, and some authors in fact have suggested that they both refer to the same property of a prosthesis. In an attempt to clarify the issue, porosity and water permeability measurements were made on 34 commercial vascular prostheses having different textile constructions. Linear regression analysis demonstrated that these two characteristics are only weakly related (r = 0.59). It is therefore recommended that the current draft standards for such devices reference both properties: porosity and water permeability.

The initial blood retention properties of arterial prostheses.

The initial contact between blood and vascular grafts may be a determinant of the fate of the implants. They behave in different ways depending upon their nature: the processed human umbilical vein and the bovine heterograft just lead to minimal thrombotic retention; the expanded PTFE is even more antithrombogenic; the porous polyesters which are porous textiles, should be totally impregnated with a thrombotic matrix to make the wall impervious. These observations were clearly determined by exposing the grafts to blood, incorporating either labeled platelets or labeled fibrinogen, and they were correlated by SEM examination.

[Rapid analysis of transferrin-iron complexes by isoelectric focusing and radioactive densitometry on gel]. / Analyse rapide des complexes transferrine-fer par isoélectrofocalisation et densitométrie radioactive sur le gel.

The analysis of the molecular forms of transferrin-iron complexes with 59Fe, was carried out using an isoelectric focusing method on commercially available polyacrylamide plates (PAG plates pH = 4-6,5, LKB). Depending upon the saturation degree of proteins with iron, apotransferrin (pI = 6,1), transferrin-Fe3+ (pI = 5,8), transferrin-2 Fe3+ (a) (pI = 5,5) and transferrin-2 Fe3+ (b) (pI = 5,3) were put forward. When the protein was saturated with iron, a double band was observed which was assigned to the microheterogeneity of the protein and depends upon the sialic content. The quantitative analysis was carried out by studying 59Fe radioactivity distribution directly on the plate. As a control, a specific staining of proteins was achieved. The interpretation of the results is difficult if such a method is used, as some bands are not attributed. Through an unspecific staining, the UV-visible densitometry is not satisfactory enough. The proposed method allows a fast analysis of transferrin-metal complexes labeled with radioactive metals. Such a method would be adaptable to the study of other complexes as transferrin-67Ga, transferrin 111In in order to determine the binding site of metal on the protein and its metal content.

Perinatal assessment of glycaemic control in newborn infants of diabetic mothers.

The glycaemic control of infants and of their mothers was studied at delivery and on day 7 after birth in 11 control and 20 insulin-dependent diabetic women. At delivery, venous blood glucose was lower in infants of diabetic mothers compared with control infants (p less than 0.02). Seven days after birth, no significant difference in blood glucose could be found between control and infants of diabetic mothers. C-peptide levels were higher in infants of diabetic mothers compared with control infants (p less than 0.01). On day 7 after birth, the C-peptide levels remained higher only in infants of Class B, C, D diabetic mothers. Glycosylated haemoglobin was lower in the venous blood of infants than of their mothers (p less than 0.001). Glycosylated haemoglobin was lower in control mothers than in diabetic mothers (p less than 0.05), but it was higher in the venous blood samples from control infants compared with infants of diabetic mothers at delivery (p less than 0.05) and 7 days after (p less than 0.01). At delivery infants' glycaemia and infants' glycosylated haemoglobin correlated (r = 0.44, p less than 0.02). C-Peptide and glycosylated haemoglobin levels in infants at delivery also correlated (r = -0.42, p less than 0.05).

[Effect of pH and the binding anion on In3+-transferrin interaction: spectroscopic study of the perturbed angular correlation of 172-245 keV gamma rays of indium 111]. / Influence du pH et de l'anion de liaison sur l'interaction In3+-transferrine: étude spectroscopique de la corrélation angulaire perturbée des raies gamma 172-245 keV de l'indium 111.

The formation of ternary complexes, transferrin-anion-In111 has been investigated by means of gamma-gamma coincidence spectrometry of the 172-245 keV rays. The angular correlation between the two gamma-rays emitted in cascade depends on the magnetic and electric fields gradients, consequently the chemical structure of metal holder. Any modification of this structure causes the variation of angular correlation. The study of G22 (infinity) as function of pH (G22(infinity): integrated perturbed angular correlation coefficient) has been performed to turn out the hydrolysis of In111 in aqueous solution, metal complex formation in presence of chelating agents (citric acid and sodium bicarbonate) and the formation of protein-metal complexes. The presence of complexing agents limits the domain of In111 colloid existence and allows fast transfer of ionised indium on the transferrin. Two types of metal-protein interactions has been turn out. The first in the weakly acidic range of pH is characterized by an affinity constant near to this of citric acid. The second lying in neutral and basic range of pH, where the formation rate of transferrin-In111 complex is fast (t less than 500 s). In citrate medium, for pH 6-7,5 the rate of metal transfer on the protein, studied by means of G22 (infinity) = f(t), is function of pH. The binding anion appears as an indispensable element for the formation of protein-metal complexes. The In111 previously chelated by 8-Hydroxyquinoline is fixed by the protein if only exits a binding anion in the solution. This mays bring in the formation of an intermediate active state, indispensable step for the ternary complex formation transferrin-anion-In111.

[First contact between blood and the arterial prosthesis. Study of the retention of the blood elements]. / Premier contact sang/prothèse artérielle. Etude de la rétention des éléments sanguins.

In order to characterize the nature of the interaction between arterial prostheses and their initial contact with blood, we propose the use of an in vitro test using labelled platelets and fibrinogen to measure the amount of the thrombotic matrix that is entrapped by the wall of the graft. The results have been confirmed by scanning electron microscopy. Polyester prostheses, whose healing process depends on the reorganisation of the thrombotic matrix, retains considerably more blood cells than the polytetrafluoroethylene microporous prostheses or the treated biological devices, whose fate, following implantation, maintains almost complete passivity.

[Radioisotope evaluation of the interaction between blood and vascular prostheses. Preliminary results]. / Evaluation radioisotopique de l'interaction sang-prothèses vasculaires. Résultats préliminaires.

In order to illustrate the phenomena which occur at the first contact between arterial prostheses and blood, an in vitro test is suggested which may be used to quantify the retention of the cruoric matrix using labelled compounds and confirming the nature by scan electron microscopy. Reorganisation of the cruoric matrix is dependent upon the scarring of polyesters which retain considerably more blood substances than microporous polytetrafluoroethylenes or the biological models dealt with, the course of which after implantation is closer to passivation.

Effect of folic acid deficiency on nonspecific immunity (phagocytic activity and nitroblue - tetrazolium reduction).

Fifty three critically ill patients (two of the following criteria : thyroxin - binding - prealbumin less than or = to 24 mg/dl, creatinin - height - index less than or = to 80 percent and transferrin less than or = to 225 mg/dl) were divided into two groups according to the level of folic acid (FA). Group A consisted of 29 with FA less than or = to 3 ng/ml and group B of 24 with FA greater than 3 ng/ml. The phagocytic activity (PA) was significantly lower in group A and significantly corrected by AB sera, whereas the NBT reduction capacities were within the normal range. A correlation is shown between PA and level of FA as well in autologous sera as in AB sera.

[Space of initial distribution of transferrin labeled with indium 113m (author's transl)]. / Espace de diffusion précoce de la sidérophiline marquée

The over-estimate of plasma volume noted at the time of the substitution of iodine 131 labeled human serum albumin by indium 113m transferrin, probably results from a defective fastening of the radionucleide on the binding protein and not at all from a particular behavior of this last one as it has often been admitted.