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Biomedical subjects

J Armand

Publications and source records attributed to J Armand.

At least 37 records · Page 2Linked to original sources
PubMed1990

Immunopharmacological activity of monoclonal antidigitoxin.

A monoclonal antibody specific to digitoxin was developed and Fab fragments were prepared using the conventional papain method. The affinity constant was determined as 10(9)M-1 and the cross reactivity with digoxin was 2%. The Fab fragments were used for the reversal of acute digitoxin poisoning in rabbits (100% mortality). Fab fragments were administered over a 40 or 80 minute period just after digitoxin infusion. Rabbits treated with specific Fab fragments were protected by a bistoichiometrical dose. Evaluation of plasma digitoxin confirmed that the specific Fab fragments were able to extract and sequestrate digitoxin. The digitoxin-Fab fragment complexes were removed by renal excretion. Our data provide evidence of the benefit of monoclonal Fab fragments specific for digitoxin for the reversal of acute digitoxin poisoning.

Animals↗
PubMed1989

Fc fragment from human IgG induces PGE2 secretion. II. Negative regulation in B cell differentiation.

In humans, in vitro, Fc fragment of IgG at a low concentration induces plasma cell generation. However, Fc fragment at a high concentration induces PGE2 release of monocyte activation capable of inhibiting this differentiation. The levels of PGE2 in the supernatant culture from mononuclear cells from normal donors were examined as a function of culture duration and concentration of Fc, Fab fragments and IgG. Plasma cells containing intracytoplasmic Ig were demonstrated by immunofluorescence with a polyvalent antiserum to human immunoglobulin(s). PGE2 levels, from mononuclear cell cultures, were analyzed by the RIA test. The results indicated that the Fc fragments are able to induce PGE2 secretion. The maximal release of PGE2 occurs after 24 hr of culture; this level is proportionate to the quantity of Fc fragments introduced. The addition of indomethacin in the cell culture stimulated by a high concentration of Fc fragments reestablishes the percentage of plasma cells. These results suggest the regulatory role of Fc fragment by PGE2 secretion in B cell differentiation.

Adult↗
PubMed1988

Human B-cell differentiation by Fc fragment of IgG. I. Fc fragment from human IgG induces plasma cell generation but cannot induce lymphocyte proliferation.

Circulating mononuclear cells (MNC) from normal donors were examined for lymphocyte proliferation and plasma cell differentiation following stimulation by Fc and Fab fragments or by intact IgG. Lymphocyte differentiation and DNA synthesis were examined as a function of culture duration and concentration of Fc, Fab fragments, and IgG. Plasma cells containing intracytoplasmic Ig were demonstrated by immunofluorescence with a polyvalent antiserum to human immunoglobulin and with specific antisera (anti-mu, -gamma, -alpha, -delta, -kappa, and -lambda chains). DNA synthesis of mononuclear cells cultures was analyzed by measuring [3H]thymidine incorporation. The results indicated that only the Fc fragments are able to induce the differentiation of B cells. The polyclonal plasma cell response to Fc fragments was dose dependent, peaked on the sixth day of culture, and was isotypically diverse (IgM greater than IgA greater than IgG). This activity requires the presence of T helper cells and monocytes. In contrast, the Fc fragments were unable to induce a proliferative response.

Adult↗
PubMed1988

Acellular pertussis vaccines: evaluation of reversion in a nude mouse model.

An animal model has been developed to assess the safety of acellular pertussis vaccines in terms of reversion to toxicity. Adsorbed pertussis toxoid preparations, alone or combined in a DTP formulation, were administered to nude mice intraperitoneally. In parallel, groups of positive and negative control mice received pertussis toxin and buffer, respectively. The circulating white blood cells of the animals were monitored for 28 days. Mice immunized with glutaraldehyde toxoid preparations did not develop a lymphocytosis during the observation period, whereas mice immunized with an experimental formalin pertussis toxoid vaccine exhibited a high lymphocytosis six days after vaccine administration, demonstrating, in this model, a reversion of the toxoid. The nude mouse model thus appears to reveal the in-vivo reversion of pertussis toxoids and could be included in the quality control panel for the assessment of the safety of acellular pertussis vaccine.

Animals↗
PubMed1987

Protective activity of Vi capsular polysaccharide vaccine against typhoid fever.

The protective efficacy against typhoid fever of a single intramuscular injection of 25 micrograms of the Vi capsular polysaccharide (CPS) was assessed in a randomised double-blind controlled trial. Vaccination of 11,384 children was followed by 21 months' surveillance. 47 blood-culture-proven cases of typhoid occurred in children who received meningococcal A + C CPS vaccine and 19 cases in those vaccinated with Vi CPS. Protective efficacy was 60% calculated from the day of vaccination and 64% from 6 weeks after vaccination. Surveillance also included 11,691 unvaccinated children; 173 cases occurred in this group. Protective efficacy in relation to the unvaccinated group was 77.4% and 81.0% after 21 months, calculated immediately and 6 weeks after vaccination, respectively. Vaccination was associated with minimum local side-effects, and an increase in anti-Vi antibodies occurred, as measured by radioimmunoassay and enzyme-linked immunosorbent assay. Antibody levels remained significantly raised at 6 and 12 months post vaccination. Vi CPS is thus a safe and effective means of typhoid vaccination.

Adolescent↗
PubMed1987

Prevention of typhoid fever in Nepal with the Vi capsular polysaccharide of Salmonella typhi. A preliminary report.

We conducted a pilot study followed by a large clinical trial in Nepal of the use of the capsular polysaccharide of Salmonella typhi (Vi) as a vaccine to prevent typhoid fever. In the pilot study, involving 274 Nepalese, there were no significant side effects of the Vi vaccine; about 75 percent responded with a rise in serum antibodies of fourfold or more. In the clinical trial, residents of five villages were given intramuscular injections of either Vi or, as a control, pneumococcus vaccine dispensed in coded, randomly arranged, single-dose syringes. There were 6907 participants, of whom 6438 were members of the target population (5 to 44 years of age); each was visited every two days. Those with temperatures of 37.8 degrees C or higher for three consecutive days were examined and asked to give blood for culture. Typhoid was diagnosed as either blood culture-positive or clinically suspected on the basis of bradycardia, splenomegaly, and fever, with a negative blood culture. Seventeen months after vaccination, the codes were broken for the 71 patients meeting the criteria for either culture-positive or clinically suspected typhoid. The attack rate of typhoid was 16.2 per 1000 among the controls and 4.1 per 1000 among those immunized with Vi (P less than 0.00001). The efficacy of Vi was 72 percent in the culture-positive cases, 80 percent in the clinically suspected cases, and 75 percent in the two groups combined. These data provide evidence that Vi antibodies confer protection against typhoid. Surveillance continues to determine the duration of Vi-induced immunity.

Adolescent↗
PubMed1985

Differential corticospinal projections in the cat. An autoradiographic tracing study.

An autoradiographic study of the corticospinal projections from different parts of the cat sensorimotor cortex produced the following findings. The lateral part of area 4 projects contralaterally to the lateral intermediate zone of the cervical enlargement only. The intermediate part of area 4 projects throughout the spinal cord, contralaterally to the lateral part of the intermediate zone and bilaterally to its ventromedial part. The lateral and medial part of area 3 project contralaterally to the cervical and lumbosacral dorsal horn (including laminae I and II), respectively.

Animals↗
PubMed1985

A new 23 valent pneumococcal vaccine: immunogenicity and reactogenicity in adults.

A 23 valent pneumococcal vaccine containing 25 micrograms of each polysaccharide was administered to 30 healthy adults. Adverse reactions were always mild, consisting only of local pain and erythema in most subjects. Pre- and four weeks post-vaccination sera were analysed by radioimmunoassay. Geometric mean titre (GMT) ratios were between 2.3 and 14.3 (overall mean X 5.7) according to type. A level of 300 ng of antibody N/ml, the supposedly protective level, was achieved in at least 86.6% of the subjects for all the serotypes.

Adult↗
PubMed1985

Tetravalent (A, C, Y, W 135) meningococcal vaccine in children: immunogenicity and safety.

Tetravalent meningococcal polysaccharide vaccine (groups A, C, Y and W 135) was administered (s.c.) to 26 healthy children, aged three to 13 years old, in order to assess safety and immunogenicity of the vaccine. Side effects were very mild in all children, generally consisting of local soreness for a few hours following injection. A fourfold increase in bactericidal antibody titres was obtained for the four components in 100% of initially seronegative children. This vaccine thus appears as safe and immunogenic in children as it is in adults.

Adolescent↗
PubMed1985

[Pneumococcal vaccination of the pregnant woman in Africa and passive immunity of the child. Immunologic control by the ELISA method].

Thirty-seven african women (mean: 23 years old) were immunized with a pneumococcal vaccine and tetanus vaccine, in a comparative study with seventeen (mean: 24 years old) women only tetanus immunized. Immune response to pneumococcal polysaccharide was studied by ELISA. All women had antibodies before vaccination. Their kinetics in mothers and infants, did not show a significant difference between the two groups. In infants, the rate of IgG antibodies significatively decreases from the date of birth to the fourth month of life. There is no foetal immunisation as shows the total lack IgM antibodies in umbilical cord blood. These results suggest that pneumococcal vaccination pregnant women in order to protect infants till 6-9 months, is not valuable.

Adult↗
PubMed1984

[The pyramidal tract. Recent anatomic and physiologic findings].

The cortical origin of the pyramidal tract is first considered. Contributions of retrograde degeneration studies as well as fiber counting method following different cortical lesions are presented and discussed. The results of these classical neuro-anatomical methods are compared with those of the more recent retrograde transport tracing method. The number and the diameter spectrum of pyramidal tract fibers differ in various mammals. In more evolved species the number of pyramidal fibers increase and their diameter span becomes wider. The thickest fibers are found in man. Along their diencephalic, mesencephalic, pontine and medullary course, axonal collaterals of corticospinal axons may terminate onto cells of origin of other descending pathways, onto relay cells of ascending pathways, and onto neurons projecting to the cerebellum. At the spinal level, the rostrocaudal extent and the termination area of corticospinal fibers may differ in various mammals. In a first group of mammals, the corticospinal fibers extend only to cervical or mid-thoracic segments and terminate in the dorsal horn. In a second group of mammals, the corticospinal fibers extend throughout the spinal cord and terminate in the dorsal horn and the intermediate zone. In a third group of mammals, the corticospinal fibers extend throughout the spinal cord and terminate in the dorsal horn, the intermediate zone and the dorsolateral part of the lateral motoneuronal cell group. In a fourth group of mammals, the corticospinal fibers also extend throughout the spinal cord and terminate in the dorsal horn, the intermediate zone and the dorsolateral as well as the ventral parts of the lateral motoneuronal cell group. A comparison is made between these different types of spinal terminations and the motor capacities of these different species. The motor deficits observed after pyramidal lesions are summarized and a comparison is made between the corticospinal tract and the descending brain stem pathways. According to electrophysiological studies in conscious animals different pyramidal units can be activated during different types of movements and at different times during the preparation or execution of a movement. Recent neuro-anatomical data suggest that the pyramidal tract is composed of many structural subsystems. Recent physiological data suggest that the pyramidal tract can be involved in various aspects of the motor control.

Animals↗
PubMed1984

A human monoclonal antibody specific for tetanus toxoid.

Successful hybridization has been obtained between PWM stimulated peripheral blood lymphocytes from tetanus toxoid immunized donors and the human B lymphoma line RH-L-4. Among the hybrids selected after cloning, the average in vitro activity against tetanus toxoid was 1-5 micrograms/10(6) cells/24 hours. The specific activity of one of them was further tested in vitro (RIA) and in vivo (mouse protection test) and compared favourably with a human polyclonal antitetanus globulin.

Animals↗
PubMed1983

Sodium diethyldithiocarbamate (imuthiol) and cancer.

Sodium diethyldithiocarbamate (imuthiol), a nonantigenic, nontoxic and noncarcinogenic compound, evinces distinctive properties in recruitment and activation of T cells, and no direct influences on B cells or macrophages. The biological attributes of imuthiol (destruction of neoplastic cells, bacteria, fungi and parasites; a detoxifying influence against carcinogens or agents toxic for the liver) could strengthen its activity as a biological response modifier. Preliminary clinic testings show that imuthiol restores T cell activities and regulates the ratio among T cell subsets in cancer patients, without untoward side effects.

Animals↗
PubMed1983

[Prospects for the vaccinal prevention of Haemophilus influenzae type b meningitis].

Haemophilus influenzae type b remains the major cause of bacterial meningitis in infants and children. Serum antibodies against the capsular polysaccharide--polyribosylribitolphosphate (PRP)--are protective, but its immunogenicity is poor in children under two years of age. Clinical trials actually in progress concerning an association of PRP with Bordetella pertussis are presented. Other vaccinal preparations are possible, such outer membrane protein, but prospects offered by polysaccharide-protein conjugates appear as the most encouraging.

Antibodies, Bacterial↗
PubMed1982

The effect of ambient chloride concentration changes on branchial chloride-bicarbonate exchanges and hemolymph acid-base balance of crayfish.

In crayfish Astacus leptodactylus maintained in 13 degrees C ambient water of constant oxygenation and acid-base balance, water chloride concentration was varied while the concentration of other ions, except sulfate, were maintained at constant values. The effects of wide variations of the ambient Cl- concentration, CCl, on the branchial titration alkalinity, delta TA, on delta CCl, delta CCO2, delta CO2 between inspired and expired water, and on the prebranchial hemolymph CCl and pH were studied. The branchial changes of TA, CCl and CCO2 were dependent on the ambient CCl, and a decrease of CCl led to a fall of CO2 excretion. Hemolymph acid-base balance closely depended on ambient CCl, particularly when CCl was less than 1 meq . L-1; when ambient CCl fell from 1 meq . L-1 to 0.1 meq . L -1, pH increased from 7.87 to 8.30. Since hemolymph PCO2 was not affected by the variations of CCl, the changes of pH are mainly explained by the concomitant changes of the hemolymph HCO3- and CO32- concentrations. During an 18-day exposure of crayfish to dechlorinated water, hemolymph CCl decreased progressively whereas its pH increased. The extreme values for CCl were 193 meq . L-1 at day 1 and 96 meq . L -1 at day 18, and the corresponding pH extremes were 7.87 and 8.65. Since the observed modifications of the branchial exchanges and the hemolymph acid-base balance were not related to the small changes of ambient osmolarity or of the SO42- or Na+ concentrations, it is inferred that they depended on a modified Cl-/HCO3- exchange mechanism in the gills.

Acid-Base Equilibrium↗