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Biomedical subjects

H Cailla

Publications and source records attributed to H Cailla.

At least 19 recordsLinked to original sources
PubMed2000

Detection of minimal levels of serum anti-Müllerian hormone during follow-up of patients with ovarian granulosa cell tumor by means of a highly sensitive enzyme-linked immunosorbent assay.

Granulosa cell tumors (GCT) are ovarian neoplasms that tend to recur and spread in the pelvis and the abdomen several years after the initial treatment. Anti-Mülerian hormone (AMH) is a reliable serum marker of these tumors. To enhance the availability and the sensitivity of serum AMH determination, we developed an ultrasensitive enzyme-linked immunosorbent assay. In this work we compare the results of serum AMH levels, obtained using the ultrasensitive and the traditional assays, in 31 patients with ovarian GCT followed up for up to 7 yr. The ultrasensitive enzyme-linked immunosorbent assay has a significantly higher sensitivity than the traditional one. This resulted in the detection of low serum AMH levels, which were undetectable with the traditional assay, in several cases including one patient in whom a recurrence of a GCT had developed and two patients in whom the treatment had not been completely successful. These cases highlight the importance of the availability of a highly sensitive assay allowing evaluation with high precision of the results of treatment and to detect the recurrences of GCT at an early, preclinical stage.

Adolescent↗
PubMed1999

[Evaluation of an immunoradiometric assay for succinylated ACTH].

A new immunoradiometric assay for succinylated ACTH using 3 monoclonal antibodies has been developed by Immunotech (I-IRMA). It was compared to a commercial immunoradiometric assay of ACTH (Nichols Institute, N-IRMA). The functional sensitivity of I-IRMA assay was estimated at 1.5 ng/L. The comparison of both methods on plasma samples withdrawn at 8 h from 47 normal subjects showed a good correlation coefficient (r = 0.83; P < 0.001). The 24-hours secretion profiles obtained by both methods were similar in 14 normal subjects. Nevertheless, the I-IRMA mean values were about 30% lower than the corresponding N-IRMA values. This difference increased to 50% when the ACTH concentrations were low, as it the case at 24 h or during the dexamethasone suppression test. During insulin hypoglycemia stimulation test, the two procedures gave similar values. Both methods applied to a pathologic population gave similar result to those obtained on normals. In 10 patients bearing corticotroph adenomas, the profiles of ACTH secretions during 24 h were similar using both methods. The I-IRMA values were lower about 30% than N-IRMA values during the base state or after the 8 mg-dexamethasone suppression test. This difference was also observed in 6 patients with corticotroph insufficiency. In conclusion, the comparison of N-IRMA and I-IRMA methods showed the validity of the new succinylated-ACTH assay which is more efficient in the lower range of ACTH concentration. This significant decrease in the sensitivity threshold may be useful in the establishment of the cure criteria in Cushing disease.

Adrenocorticotropic Hormone↗
PubMed1998

Immunoradiometric assay of succinylated corticotropin: an improved method for quantification of ACTH.

In this paper we describe the development and the evaluation of a new type of immunoassay for human corticotropin (ACTH). We succeeded, by using an original approach based upon immunization with ACTH derivatized with succinic anhydride, in raising monoclonal antibodies against this poorly immunogenic peptide. Three of the antibodies were selected to develop an immunoassay for ACTH. The assay requires the prior succinylation of the plasma samples for optimal sensitivity and specificity. This acylation treatment is fast, reproducible, and, in addition, improves the stability of the ACTH molecule in plasma, thus facilitating sample handling. The assay is performed in only 3 h with a detection limit of 0.7 ng/L. Analytical evaluation showed excellent specificity, reproducibility, and reliability. A comparison with two commonly used but time-consuming ACTH IRMAs was carried out by assaying several plasma samples in parallel and gave in both cases very good correlation.

Adrenocorticotropic Hormone↗
PubMed1997

A novel method for the production of antibodies against ACTH: their characterization and use in epitope mapping.

Our earlier attempts at immunization with human adrenocorticotropin hormone (ACTH) were unsuccessful and we therefore developed a new strategy including the chemical modification of the hormone by succinic anhydride in order to increase its immunogenicity. This process allowed us to obtain antisera with titers of up to 1/1000 and yielded 39 anti-succinylated ACTH (sACTH)-secreting hybridomas. Subsequently, the epitopes of sACTH were mapped by testing monoclonal antibodies two by two for simultaneous binding to sACTH and for their capacity to recognize its succinylated fragments 1-13, 1-17 and 1-24. The results, obtained with the use of radioactive tracers, were confirmed by and complemented with experiments conducted with biosensor technology. Seven groups of antibodies were defined on the basis of their pattern of reactivity and it was shown that four monoclonal antibodies could bind simultaneously to sACTH. Their dissociation constants (Kd) for sACTH were calculated and ranged from 10(-8) M to 10(-11) M. In order to obtain a fast and sensitive immunoassay for the hormone, we developed a protocol for the chemical modification of ACTH in serum and the most efficient monoclonal antibodies were selected on the basis of the epitope map and of their dissociation constants.

Adrenocorticotropic Hormone↗
PubMed1990

Radioimmunoassay of a new angiotensin-converting enzyme inhibitor (perindopril) in human plasma and urine: advantages of coupling anion-exchange column chromatography with radioimmunoassay.

Perindopril (P) is a prodrug whose active metabolite perindoprilat (PT) is an antihypertensive agent which acts by inhibition of angiotensin-converting enzyme (ACE). Anti-PT antiserum was produced in a rabbit immunized against PT that was covalently linked to bovine serum albumin. The radioligand is an iodinated (125I) derivative of PT-glycyltyrosinamide. Both the drug (PT) and the prodrug (P) are assayed in the same sample; PT is assayed as is and P is assayed after quantitative alkaline hydrolysis into PT. Certain data obtained from such assays suggest the occurrence in plasma and urine of a third immunoreactive component. A chromatographic fractionation of samples allowed us to isolate a new immunoreactive metabolite which was further identified as a glucuronide of PT (PT-G). Therefore, the whole assay was carried out as follows: biological samples were fractionated by stepwise chromatography on a anion-exchange resin (the first fraction contained P, the second contained PT, and the third contained PT-G); and RIA was performed on fractions 2 and 3 as is, and on fraction 1 after alkaline hydrolysis. Performances and assessments of this method are presented together with an example of a pharmacokinetic profile.

Adult↗
PubMed1987

Do viruses play an etiologic role in ankylosing spondylitis or psoriatic arthritis?

High venous blood levels of 2-5A, an adenylic acid polymer synthesized in the presence of double-stranded RNA and considered as a viral replication indicator, have been found in blood samples from ankylosing spondylitis and psoriatic arthritis patients, but not from patients with seropositive rheumatoid arthritis or acute chondrocalcinosis. These findings suggest the possibility that ankylosing spondylitis and psoriatic arthritis might be virus-induced diseases.

Adenine Nucleotides↗
PubMed1987

Epitope design for the induction of antibodies which recognize a family of molecules: example of monoclonal antibodies to 2'-5' oligoadenylates.

Monoclonal antibodies directed against 2'-5' oligoadenylates (pxA(2'pA)n 0 less than or equal to x less than or equal to 3, n greater than or equal to 1) have been obtained with A2'pA-succinyl albumin as immunogen. A competition assay using 125I iodo succinyl A2'pA tyrosine methyl ester as a tracer and thirty chemically related analogs was used to investigate the molecular basis governing their reactivity. We show that the use of a hapten as small as A2'pA elicits antibodies of high affinity for this dinucleotide (Kd = 2 x 10(-11) M). The overall immunoreactivity is essentially shared between the first moiety (5'OH A2'p) and the 2'-5' phosphodiester bond; however, the second moiety is an integral part of the epitope which extends up to the spacer. Therefore, any modification at the 5'OH end or of the 2'-5' structure dramatically decreases the binding. Modifications at the 2' and/or 3' ends are favourable if they mimic the immunogen. Modifications of the ribose backbone reveal the part of antigenicity due to the different 3'OH groups. Substitution of the bases show that the second adenine is implicated in the antigenicity. We demonstrate how, with such requirements, these antibodies recognize A2'pA alone or at the 5' end of or else included in longer oligonucleotides.

Adenine Nucleotides↗
PubMed1986

Interferon-alpha, beta and -gamma induce (2'-5') oligoadenylate synthetase in cultured mouse brain cells.

Basal and interferon (IFN)-induced levels of (2'-5') oligoadenylate synthetase activity were measured in astrocyte cultures from the mouse cerebral cortex, in neurone-enriched and mixed cerebellar cultures, and in two continuous neural cell lines by a radioimmunoassay procedure. All untreated cultures contained measureable enzyme activity. Both purified IFN-alpha, beta and recombinant IFN-gamma induced the enzyme in all cultures with the exception of the C8S cell line which did not respond to IFN-gamma. IFN-alpha, beta was more effective than IFN-gamma. The amplitude of induction by IFN-alpha, beta was highest in the cell lines, intermediate in cortical astrocytes and lowest in mixed and neurone-enriched cultures from the cerebellum.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

Comparison of the effects of rabies virus infection and of combined interferon and poly(I).poly(C) treatment on the levels of 2',5'-adenyladenosine oligonucleotides in different organs of mice.

Intracellular levels of 2',5'-adenyladenosine oligonucleotides were analyzed in different organs of mice during the course of a rabies virus infection. Phosphorylated and nonphosphorylated 2',5'-adenyladenosine oligonucleotides were measured by radioimmunoassay and analyzed further by HPLC. As the infection progressed, concentrations of phosphorylated 2',5'-adenyladenosine oligonucleotides increased strongly, reaching their maxima late in the infection. In contrast, concentrations of the nonphosphorylated 2',5'-adenyladenosine oligonucleotides decreased. A similar phenomenon was observed in spleens analyzed at intervals after treatment of noninfected mice with interferon and poly(I).poly(C) and to a lesser extent after treatment of noninfected mice with interferon and poly(I).poly(C) and to a lesser extent after treatment with poly(I).poly(C) alone, but not after treatment with interferon alone. The products which accumulated during virus infection were primarily phosphorylated dimers whereas during combined interferon and poly(I).poly(C) treatment, the entire range of phosphorylated molecules from dimer to pentamer was present. These data show that infection of mice with rabies virus provokes both the induction and the activation of 2-5A synthetase, as does interferon and poly(I).poly(C) treatment. However, our data indicate that the intracellular products are different in the two situations: the species active on the nuclease were only detected in interferon- and poly(I).poly(C)-treated mice. The absence of molecules able to activate the 2-5A-dependent nuclease in virus-infected mice might well be one of the reasons why the interferon system is ineffective in rabies virus infection.

Adenine Nucleotides↗
PubMed1984

Immunological evidence for the in vivo occurrence of (2'-5')adenylyladenosine oligonucleotides in eukaryotes and prokaryotes.

A monoclonal antibody highly specific for (2'-5')adenylyladenosine oligonucleotides was used together with a 125I-labeled analog of this compound to detect and quantify phosphorylated and nonphosphorylated (2'-5')adenylyladenosine oligonucleotides in a variety of tissues and cells. These oligonucleotides were first assayed as a whole in perchloric acid extracts and then further individually characterized by HPLC analysis. Their sensitivity to alkaline phosphatase, snake venom phosphodiesterase, and T2 RNase was systematically checked. Nonphosphorylated (2'-5')adenylyladenosine oligonucleotides were found in mammalian tissues as well as in yeast and bacteria. In normal mouse brain, lung, heart, pancreas, spleen, kidney, and liver their concentrations ranged from 10 to 200 pmol/g wet weight, depending on tissue and strain. The oligonucleotides were mainly dimers, trimers, tetramers, and pentamers. In addition, phosphorylated (2'-5')adenylyladenosine oligonucleotides were shown in liver and kidney extracts.

Adenine Nucleotides↗
PubMed1982

2' and 3' ribonucleoside monophosphate in leukocytes of acute myeloid leukemia: markers for early diagnosis of relapse.

Levels of 2' and 3' purine and pyrimidine ribonucleoside monophosphates (2'-, 3'-NMP) in leukocytes from blood and/or bone marrow were measured in three adult patients with acute non-lymphoblastic leukemias. The measurements of 2'-, 3'-NMP were made by high-performance liquid chromatography (HPLC) at various times in the course of the disease. Complete remission (CR) was obtained for all three patients but two of these have since died after relapsing at 8 and 9 months, respectively. The third patient remains in CR at 1 1/2 year. The levels of 2'-, 3'-NMP in the leukocytes of the patient remaining in remission have not changed since the beginning of his remission. However, in the patients who relapsed 2'- and 3'-NMP levels increased first in bone marrow than in blood leukocytes. These increases occurred about 3 months before the relapse was detected by morphological criteria. These data suggest that 2'-, 3'-NMP measurements may have a prognostic value if used to monitor patients with acute myeloid leukemia in CR.

Adenosine Monophosphate↗
PubMed1982

Monoclonal antibodies to 5'-triphospho-(2'-5')adenyladenosine oligonucleotides.

Thirteen monoclonal antibodies to ppp(A2'p5')nA oligonucleotides have been produced by fusing Y3 myeloma cells with spleen cells of rat hyperimmunized with A2'p5'A succinyl albumin as immunogen. 125I-labeled A2'p5'A succinyl tyrosine methyl ester was used as a labeled probe. Antibodies were detected by their ability to bind the labeled analog and were selected for their affinity for A2'p5'A. There were no significant differences between the properties of the monoclonal antibodies and of the antiserum. They discriminated between 2'-5' and 3'-5' phosphodiester bonds: they crossreacted poorly with (A3'p5')2A (crossreactivity ratio, greater than 10(4)) and even less with ATP an adenosine (crossreactivity ratio, greater than (6)). The affinity was high (Kd = 6 x 10(-12) M) for succinyl A2'p5'A, which is the best ligand, and also high for A2'p5'A (crossreactivity ratio, 3) and (A2'p5')2A, (A2'p5')3A, and (As'p5')4A (crossreactivity ratio, 7.5). The binding to triphosphorylated isomers, ppp(A2'p5)nA, was affected by the presence of the triphosphate groups, and the affinity increased as the length of the isomer increased (crossreactivity ratio, 10,000 for n = 1 to 200 for n = 4). Thermodynamic analysis of these data demonstrated that, in dephosphorylated isomers, the binding site of highest affinity was located at the 5'-OH end of the molecule whereas in phosphorylated isomers, the favorable binding sites were in the middle and at the 2'-OH end of the chain. Use of monoclonal antibodies of such a specificity together with the 125I-labeled 2-5A analog allows quantification of (A2'p5')nA directly and of ppp(A2'p5')nA after removal of the terminal phosphates by alkaline phosphatase treatment.

Adenine Nucleotides↗
PubMed1981

Influence of parathyroid status of rats on renal tubular handling of adenosine 3'5'-monophosphate: a micropuncture study.

In order to correlate cyclic AMP handling by the nephron to the parathyroid status, clearance and micropuncture experiments were performed in rats with intact parathyroid glands, or immediately after parathyroidectomy, or six days after parathyroidectomy. In intact animals cyclic AMP urinary excretion was about twice the filtered load and the tubular addition of the nucleotide was achieved at the end of the accessible proximal tubule. In acutely parathyroidectomized rats cyclic AMP urinary excretion was not different from the filtered load and no proximal tubular addition was detected at the late accessible proximal tubule. In chronically parathyroidectomized animals urinary excretion of cyclic AMP was not different from the filtered load, nevertheless a proximal tubular addition of the nucleotide was observed, similar in magnitude to that of intact rats. The data afford a direct evidence that the convoluted proximal tubule is the major site of cyclic AMP tubular addition, confirm that this addition disappears immediately after parathyroidectomy, but indicate that it re-occurs in chronic parathyroidectomy.

Animals↗
PubMed1980

Further studies on the effect of cholecystokinin and secretin on the content of cyclic AMP, cyclic GMP, protein and calcium in pure pancreatic juice of dogs.

The present work deals with the time course of pancreatic secretion of cyclic AMP, cyclic GMP, calcium and protein in response to cholecystokinin (CCK) and secretin (S). Three dogs with gastric and duodenal Thomas cannulae were given 1 Clinical Unit/kg/h of secretin for 150 min. CCK was added to the infusion after the first 75 min. Only one dose of CCK (0.75, 1.5, 3, 6, 16 24 Ivy dog U/kg/h) was given in any one experiment. Pancreatic juice was collected at one minute intervals for the first 15 min. at the beginning of the CCK infusion and at 15 min. intervals thereafter. CCK induced a biphasic pattern of pancreatic secretion: within 3 to 10 min. flow rate, protein, calcium, cyclic AMP and cyclic GMP output peaked in a dose dependent parallel manner. Then, the maximal flow remained constant while protein output reached a steady state; its value was fairly similar to that of the early peak for 0.75 to 6 U and for 16 and 24 U, the steady state value was lower than the first peak value. The pattern of calcium output was similar to that of protein output. The output of cyclic AMP and cyclic GMP increased until the end of the CCK infusion. When CCK (3 U/kg) was given as an intravenous bolus injection without any background of secretin, cyclic AMP, cyclic GMP and protein outputs peaked within 3 min. and then decreased. The results show that not only calcium and protein but also cyclic AMP and cyclic GMP secretion in the pancreatic juice depends on CCK. Key words: Dog, secretin, cholecystokinin, pancreatic juice: cyclic AMP, cyclic GMP, calcium, protein.

Animals↗