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A Adam

Publications and source records attributed to A Adam.

At least 181 records · Page 10Linked to original sources
PubMed1991

Enzyme-linked immunosorbent assays and developments in techniques using latex beads.

Not surprisingly, most of the publications on enzyme immunoassays or latex agglutination tests in 1990 have been applications for specific antigens or antibodies. Nevertheless, a large number of studies of considerable interest to all users have been reported. In this short review, we have chosen to highlight investigations into: factors affecting assay performance; enzyme immunoassay design and statistical analysis; novel approaches in enzyme immunoassays and related techniques; immunohistochemistry; and latex agglutination tests.

Agglutination Tests↗
PubMed1991

Percutaneous transcaval tumour biopsy using a 'road-map' technique.

The 'road-map' facility available on some of the commercially available digital subtraction angiography units is usually used to aid in the selective catheterization of a vessel during arteriography. We describe its use in the percutaneous transcaval biopsy of tumour within the inferior vena cava (IVC).

Aged↗
PubMed1991

A competitive enzyme immunoassay for albuterol: its application for the drug screening in urine.

A competitive enzyme immunoassay using purified monoclonal IgG1 and an alkaline phosphatase-albuterol derivative has been developed for the quantification of albuterol in urine. The calibration curve obtained in optimal incubation conditions is characterized by a minimum detectable level of 26 fmol/well and a working range from 52 fmol to 4,2 pmol/well. This method allows the precise and accurate quantification of albuterol in horse urine without any clean up or extraction step. Moreover the definition of its specificity shows a cross-reactivity of the antibody with the glucurono-/sulfo-conjugates of albuterol. This property is particularly interesting for the screening of urinary albuterol residues in meat producing animals.

Albuterol↗
PubMed1991

Increase in urinary kallikrein excretion following hemodialysis.

Urinary kallikrein excretion (UKE) was measured in 20 patients before and after hemodialysis (HD). When compared to the values of normal subjects (136 +/- 56 micrograms/24 h, n = 100), UKE was decreased in all patients before HD (6.6 +/- 5.8 micrograms/24 h, p less than 0.001, n = 20). After HD a significant increase in 24-hour UKE was observed in all patients (18.6 +/- 7.2 micrograms/24 h, p less than 0.05, n = 20). Expressed as the individual percent increase, the UKE enhancement ranged from 16 to 670%. It was due to an enhancement in the excretion of the active form which represented 52 +/- 6.8% before HD and reached 76.3 +/- 7.5% of the total form after HD (p less than 0.01). The excretion of the inactive form remained unchanged. The increase in UKE was found to be significantly correlated with reductions in urinary sodium, potassium, and osmolality (r = -0.826, r = -0.568, r = -0.847, respectively, p less than 0.01, n = 20). The increase in UKE following HD could not be explain by an increase in aldosterone as urinary aldosterone decreased. A transient improvement in intracellular homeostasis (removal of inhibitory toxins and normalization of osmotic pressure) could be evoked. The increase in UKE 24 h after HD points out a new situation confirming the relations of UKE with changes in osmolality and extracellular volume.

Adult↗
PubMed1991

Self-expandable stainless steel endoprostheses for treatment of malignant bile duct obstruction.

The Wallstent biliary endoprosthesis is a mesh of stainless steel that is delivered percutaneously over a 7-French catheter but expands to achieve a 1-cm lumen when released across a bile-duct stricture. The small transhepatic track required makes insertion easier, less painful, and probably safer when compared with plastic stents, and the large internal lumen reduces the rate of occlusion by encrusted bile. Wallstent endoprostheses were inserted under local anesthesia in 41 consecutive patients with malignant obstructive jaundice. Biliary drainage was considered the treatment of choice in all of these patients. The diagnosis was based on biopsy results in 32 patients and on radiologic appearances in nine. The patients were followed up in outpatient clinics for 16 months and had repeated radiologic examinations only if they had symptoms suggesting stent occlusion. No cases of hemobilia due to damaged hepatic vessels occurred. Two patients had septicemia treated with antibiotics. Three patients had recurrent jaundice due to growth of tumor below or above the stents. Endoprosthesis migration was not seen. No cases of stent occlusion due to encrustation of bile occurred. The median survival of patients was 105 days (range, 10-545 days). Our experience shows that Wallstent endoprostheses can be inserted with little discomfort for the patient and with relatively few complications. They provide good palliation in patients with malignant obstructive jaundice.

Adult↗
PubMed1991

Myeloperoxidase and elastase as markers of leukocyte activation during cardiopulmonary bypass in humans.

To assess leukocyte activation during cardiopulmonary bypass, we measured white blood cell and neutrophil counts and lysosomal enzyme release, especially myeloperoxidase and elastase, throughout the operation and for 5 days postoperatively. A newly developed double antibody radioimmunoassay of myeloperoxidase and an enzyme-linked immunosorbent assay for detection of the polymorphonuclear elastase-alpha 1-proteinase inhibitor complex were used to determine their plasma levels in 15 patients undergoing elective aorta-coronary bypass grafting. Preoperatively white blood cell counts and plasmatic levels of myeloperoxidase and elastase-alpha 1-proteinase inhibitor were normal. Because no correlation has yet been established between levels of myeloperoxidase and elastase-alpha 1-proteinase inhibitor, the aim of this prospective study was to evaluate the use of these enzyme levels as markers for leukocyte activation in vivo. We addressed the clinical situation of cardiopulmonary bypass because it offered the possibility of monitoring the comparative evolution of blood levels of these enzymes in parallel to white blood cell counts through well-defined steps corresponding to known events. We document the advantages of myeloperoxidase blood levels over elastase measurement as reflecting more rapidly the in vivo activation of leukocytes. The time course kinetics of these three measurements were not parallel. White blood cell counts remained stable at the beginning of bypass, whereas myeloperoxidase levels increased sharply and continuously as soon as bypass was instituted until the end of bypass. Elastase levels also increased, but later than myeloperoxidase, beginning when the patients was rewarmed. High elastase plasma levels persisted later than myeloperoxidase after bypass, in parallel with white blood cell counts. It thus clearly appears that changes in myeloperoxidase levels more rapidly reflect the activation state of leukocytes induced by cardiopulmonary bypass and surgery, whereas peak levels of elastase were delayed and parallel to white blood cell counts. From this model, in which the evolution of leukocyte numbers could be followed in relation with known steps of stimulation, it appears that myeloperoxidase is a sensitive marker for monitoring in vivo activation of white blood cells.

Adult↗
PubMed1990

An evaluation of the redox cycling potencies of paraquat and nitrofurantoin in microsomal and lung slice systems.

The redox cycling abilities of the pulmonary toxins paraquat and nitrofurantoin have been compared with those of the potent redox cyclers, diquat and menadione in lung and liver microsomes by using the oxidation of NADPH and consumption of oxygen. The relative potencies of these compounds to undergo redox cycling were in the order: diquat approximately menadione much greater than paraquat congruent to nitrofurantoin. This was partly attributed to the much lower affinity (Km) of lung and liver microsomes for paraquat and nitrofurantoin than for diquat and menadione. The potential to redox cycle was assessed in an intact cellular system by determining the oxygen consumption of rat lung slices in the presence (10(-6), 10(-5) and 10(-4) M) or absence of each of the four substrates. At concentrations of paraquat (10(-5) M) known to be accumulated by lung slices, a small but significant stimulation of lung slice oxygen uptake was observed. Nitrofurantoin (10(-4)-10(-6) M) did not affect lung slice oxygen uptake in lung slices, an observation consistent with its being a poor redox cycling compound, which is not actively accumulated into lung cells. This data has important implications in assessing the risk of exposure to paraquat. Low levels of paraquat would not be expected to cause lung damage because insufficient compound is present in the lung to exert its toxicity by redox cycling (due to the high Km observed).

Animals↗
PubMed1990

Potentiation of the cell specific toxicity of paraquat by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). Implications for the heterogeneous distribution of glutathione (GSH) in rat lung.

In order to study oxidative stress in the lung, we have developed a rat lung slice model with compromised oxidative defences. Lung slices with markedly inhibited glutathione reductase activity (approximately 80% inhibition) were prepared by incubating slices, with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) (100 microM) in an amino acid-rich medium for 45 min at 37 degrees. These lung slices had similar levels of GSH and ATP and polyamine uptake (a marker of alveolar epithelial type I and II cell function) to control rat lung slices. We have utilized these BCNU pretreated slices to study the effects of the herbicide, paraquat, in comparison to those of 2,3-dimethoxy-1,4-naphthoquinone, a potent redox cycler. Paraquat (10-100 microM) caused only minimal changes in the levels of GSH or ATP in control or compromised slices. In contrast, 2,3-dimethoxy-1,4-naphthoquinone caused a decrease in GSH in control slices but a markedly enhanced decrease in both GSH and ATP in compromised slices. Both compounds had only limited effects on putrescine and spermidine uptake in control slices. However, they caused a marked inhibition in compromised slices. Paraquat had little effect on 5-hydroxytryptamine uptake (a marker of endothelial cell function) in either control or compromised slices whereas the quinone inhibited uptake in the compromised slices. Thus, the lack of effect of paraquat on GSH and ATP does not support the involvement of oxidative stress in its toxicity. In contrast, using polyamine uptake, as a functional marker of alveolar epithelial cell damage, suggests a role for redox cycling. As paraquat is known to be accumulated primarily in alveolar type I and II cells (a small fraction of the lung cell population), our data suggest that only a small proportion of pulmonary GSH and ATP is present in alveolar epithelial type I and II cells but that much larger amounts may be present in endothelial cells. These studies highlight the problem of gross tissue measurements in heterogeneous tissues such as the lung.

Adenosine Triphosphate↗
PubMed1990

Proteinase inhibitors, kinins and the inflammatory reaction induced by sponge implantation in rats.

We studied the influence of aprotinin and soya bean trypsin inhibitor (SBTI) on the inflammatory reaction induced by the implantation of dry sponges in normal Wistar rats and in kininogen-deficient Brown Norway rats, during the first day after the implantation. In normal rats, aprotinin reduced the volume and total protein content of the exudates at 3 h but not thereafter. Aprotinin also markedly reduced the immunoreactive kinins and kallikrein in the exudates. Aprotinin did not modify the volume of the exudates of the Brown Norway rats. SBTI reduced the inflammatory reaction in both rat strains but did not significantly modify the formation of immunoreactive kinins. The inflammatory reaction developed more slowly in Brown Norway rats. The kinin system is thus involved during the first hours of the development of this acute inflammatory reaction. The anti-inflammatory effect of SBTI does not depend on the inhibition of kinin formation.

Animals↗
PubMed1990

Macrophages from C3H/HeJ mice require an additional step to produce monokines: synergistic effects of silica and poly(I:C) in the release of interleukin 1.

Resident macrophages from C3H/HeJ mice, in contrast with those of other strains of mice such as BDF1 mice, did not release a 35 kD m.w. factor having macrophage replacing activity (FRM) or interleukin 1 (IL-1) when, respectively, cultured alone or in the presence of silica. C3H/HeJ macrophages were nevertheless capable of producing an intracellular IL-1-like activity. In addition, after a two-step activation process, macrophages from BDF1 mice spontaneously released IL-1, whereas silica was required to induce the release of IL-1 from similarly treated C3H/HeJ macrophages. Such in vivo primed and in vitro stimulated macrophages failed to release FRM. In contrast, poly(I:C) was able to induce the release of FRM by C3H/HeJ macrophages but not that of IL-1; moreover, the addition of silica to poly(I:C)-stimulated cells led to an IL-1 release similar to that obtained with normal mice treated with silica alone. Since poly(I:C) is able to elicit the production of interferons (IFN), the involvement of IFNs was investigated in poly(I:C) activity. Neither IFN-alpha/beta nor IFN-gamma, when used alone or in the presence of silica, could induce the release of IL-1 by C3H/HeJ macrophages. In addition, antibodies to IFN-alpha/beta and IFN-gamma were unable to affect the poly(I:C) and silica induced release of IL-1. Thus, the signal provided by poly(I:C) does not appear to be mediated by IFN(s).

Animals↗
PubMed1990

Muramyl dipeptide (MDP) synergizes with interleukin 2 and interleukin 4 to stimulate, respectively, the differentiation and proliferation of B cells.

The synthetic immunomodulator muramyldipeptide (MDP) can stimulate B cells. MDP, when used alone, was apparently unable to induce the differentiation or proliferation of resting B cells. In contrast, MDP appeared to synergize with a single recombinant interleukin (IL) to stimulate either their differentiation or proliferation. We used single interleukins to avoid synergistic and antagonistic effects inherent in the use of several factors. IL-2 was found to be sufficient to restore the specific immune response of resting B cells to sheep erythrocytes; MDP greatly increased the number of plaque-forming cells of such IL-2-stimulated B cells. In contrast, IL-4 and interferon-gamma (IFN-gamma), either alone or in the presence of MDP, had no effect in this differentiation assay. MDP was also able to stimulate polyclonally activated B cells. IL-4 increased the proliferation of anti-IgM-stimulated B cells, leading to enlargement and driving more cells into the cell cycle; these effects were further enhanced by MDP, more cells being induced to proliferate, to enlarge, and to progress into the cycle with a higher frequency of cells in the G1B, S, and G2/M compartments. Intracellular free calcium levels were not increased by IL-4 and/or MDP, and the two compounds did not modify the anti-IgM-induced calcium mobilization. Therefore, MDP appears to amplify cytokine effects in B cell activation, by a mechanism which does not appear to involve free calcium mobilization.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Increased expression of alkaline phosphatase activity in stimulated B lymphocytes by muramyl dipeptide.

We have recently shown that the synthetic immunomodulator muramyl dipeptide (MDP) acts on murine B lymphocytes. It synergizes with interleukin 2 and interleukin 4 to stimulate, respectively, the differentiation and the proliferation of B cells. In the present study, MDP was shown to increase the proliferation of B cells stimulated by lipopolysaccharide (LPS). Moreover, the expression of alkaline phosphatase activity induced by LPS was markedly enhanced by MDP. These effects were time- and dose-dependent. The present report suggests that the biochemical mechanism by which MDP exerts its effects may involve protein phosphorylation-dephosphorylation pathways.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Wallstent endoprostheses for the relief of prostatic urethral obstruction in high risk patients.

Twenty-one patients with prostatic urethral obstruction who were unfit for surgery were treated with self-expandable stainless steel endoprostheses inserted under fluoroscopic guidance. The procedure was technically successful in all patients, although in one case a second stent was required 2 months later. One patient developed a urethral stricture in the 12-16 month follow up period. One case of epididymoorchitis and one case of septicaemia after stenting were treated successfully with antibiotics. Endoprostheses represent a satisfactory alternative to prostatectomy in high-risk patients.

Aged↗
PubMed1990

Radioimmunoassay for albuterol using a monoclonal antibody: application for direct quantification in horse urine.

A monoclonal antibody was synthesized in mouse against the O-(3-carboxypropionyl) derivative of albuterol linked to bovine serum albumin. Isotyping of this material revealed the IgG1 class characterized by an affinity constant of 1.03 nM-1 and a density of sites of 0.55 nM. This antibody was found specific as its cross-reactivity to structurally related molecules was less than 1% except for clenbuterol (75%). A radioimmunoassay was set up with culture supernatant (final dilution 1/1000) and [3H] albuterol. The calibration curve was characterized by a maximum binding of 28%, an ED50 of 1.15 pmol per tube, the detection limit was 28.8 fmol/tube and the linearity of the response was up to 39.8 pmol/tube. This RIA method has been used for direct quantitation of albuterol in horse urine without any clean-up or extraction step.

Albuterol↗