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Biomedical subjects

G Messeri

Publications and source records attributed to G Messeri.

At least 55 records · Page 3Linked to original sources
PubMed1988

A new approach to the quality control of steroid receptor assays.

Lyophilized cytosols prepared from calf uterus and human breast tumor tissue are commonly used to assess the reliability of routine steroid receptor assays. However, preanalytical error (sample preparation, storage, homogenization) cannot be detected in this way. Participating laboratories were asked to mail us all their receptor results obtained over a four-month interval, and to include some information about the patients involved (age, menopausal status, nodal status). After verifying the homogeneity of the populations investigated, we computed consensus means for the percentages of positive samples and for their absolute value. Despite the homogeneity of the characteristics of the populations studied, results from some laboratories systematically differed from the consensus mean. This approach to the quality control of steroid receptors allows evaluation of the whole procedure, from sample preparation to analysis, and thus may be helpful as an addition to the usual practice of distribution of cytosols and tissue powders for assay.

Age Factors↗
PubMed1987

Cyclical Cushing's disease: report of a case cured by conventional cobaltotherapy.

Preliminary hormonal studies in a 18-y old man with the clinical features of Cushing's syndrome showed inconclusive and conflicting results both in basal conditions and after metyrapone and dexamethasone administration. Therefore the possibility of a cyclical or acyclical fluctuation of adrenal hypersecretion was suspected and the patient was observed for an extended period of time free of hormonal manipulations. Regular cycles of cortisol hyperproduction, with peaks occurring every 6.0 days were found. Ectopic ACTH production was ruled out and, even in the absence of radiological evidence of a pituitary adenoma, conventional cobaltotherapy was suggested after refusal of transsphenoidal pituitary surgery. About 8 months later a marked clinical improvement was evident as well as normalization of hormonal data with loss of the cyclical pattern. Remission of the disease was still persistent 15 and 28 months later. A recent control, approximately 4 1/2 yr after treatment confirmed the normalization of biochemical data, suggesting a cure of the disease.

Adolescent↗
PubMed1987

Polyamine modification in human breast tumors after short treatment with tamoxifen.

The authors measured estrogen receptors, and polyamine (putrescine, spermidine and spermine) in breast tumors from patients (n = 23) who had received tamoxifen for a few days (5-10) before surgery. Women undergoing mastectomy without any preoperatory treatment were selected as the control group (n = 44). As already reported about in vitro experiments, the treatment resulted in a significant lowering of the spermidine to spermine ratio. Such a modification was larger in the ER positive tumors then in the ER negative ones and it seems to be related to the regression process of the drug-responsive tumors. On the basis of the experimental data the authors suggest the development of a in vivo tamoxifen-sensitivity test.

Aged↗
PubMed1987

Chemiluminescence immunoassay for somatomedin C in serum.

To select the best tracer for use in a competitive immunoassay, we conjugated human somatomedin C (SmC) to various chemiluminescent compounds via two different synthetic pathways. Naphthylhydrazides and arylhydrazides, used as the labels, were incorporated via their imidate or their succinimide esters. Conjugating the carboxy terminal of (amino ethyl)ethyl-isoluminol to SmC via a succinimide linkage supplied the most sensitive detection limit and the most immunoreactive conjugate. We developed an immunoassay based on the use of this conjugate, and evaluated dextran-coated charcoal, second-antibody precipitation, and solid-phase immunoprecipitation for separating bound and free label. This chemiluminescent method has a detection limit of 16 pg per tube, and it is accurate and precise. Correlation studies with a conventional radioimmunoassay (x) for SmC gave the following regression equation: y = 0.66x + 3.76 (r = 0.953, n = 30); the slight discrepancies between the two methods are probably ascribable to the use of different antibodies. We thus propose this chemiluminescence immunoassay as an inexpensive and sensitive alternative to radioimmunoassay for measuring SmC in serum or in extracts of serum.

DNA, Recombinant↗
PubMed1986

Measurement of transferrin in human seminal plasma by a chemiluminescent method.

We describe a luminescence immunoassay for measuring transferrin in human seminal plasma. Human transferrin conjugated with 7-[(N-4-aminobutyl)-N-ethylamino]naphthalene-1,2-dicarboxylic acid hydrazide was used to monitor the immunological reaction. The conjugate was stable for at least one year. The sensitivity (2 ng per tube) of the assay allows measurement of this protein in diluted seminal plasma. Results by this method (y) correlated well (r = .9681) with those by a conventional RIA method (x): y = 1.000x + 1.646 micrograms per ejaculate. Seminal transferrin concentrations are reported for normal control subjects, vasectomized subjects, and infertile patients. The method described appears suitable for measurement of seminal transferrin as an index of Sertoli cell function in male infertility.

Humans↗
PubMed1985

Pregnanediol-3 alpha-glucuronide measured in diluted urine by mass spectrometry with fast atom bombardment/negative-ion ionization.

We describe a mass-spectrometric method based on the fast atom bombardment ionization technique in the negative-ion mode for measuring pregnanediol-3 alpha-glucuronide in diluted urine from women. The procedure requires addition of testosterone-17 beta-D-glucuronide (2.5 micrograms/25 microL) to the urine sample as internal standard, and the sample is added directly to the fast atom bombardment target with no further manipulation. We have assessed and evaluated the method by the traditional criteria of reliability.

Adult↗
PubMed1984

Helix pomatia induced conversion of some 3 beta-hydroxysteroids.

After incubating a dehydroepiandrosterone solution with an enzymatic preparation from Helix pomatia, the steroid recovery was markedly decreased. The transforming activity resulted specific for some 3 beta-hydroxysteroids and it appeared to lower after storing the preparation at 4 degrees C for some days. The presence of 4-androsten-3,17-dione within the incubation products suggests that the enzymatic preparation contains at least 3 beta-hydroxysteroid: NAD oxydoreductase and 3-oxosteroid-5-4-ene isomerase. The use of large amounts of freshly dissolved Helix pomatia juice solution may lead to unreliable results in steroid analyses.

Animals↗
PubMed1984

Homogeneous luminescence immunoassay for total estrogens in urine.

We describe an homogeneous luminescence immunoassay for "total" estrogens in enzymically hydrolyzed urine from nonpregnant women. The antiserum, raised against estriol-16,17- dihemisuccinate conjugated to bovine serum albumin, specifically bound the C-19 steroids carrying the estrogen-characteristic phenolic group. 17 beta-Estradiol conjugated with aminobutylethyl isoluminol was used to monitor the immunological reaction; this conjugate was stable for at least two years. Because binding to the antiserum markedly enhances the light-producing efficiency of the tracer, no separation of bound and free antigen is necessary. Results (microgram/24 h) by this method (y) correlated well (r = 0.958) with those by a conventional fluorometric (x) method (y = 2. 51x - 2.83). The sensitivity (detection limit) is 4 micrograms/L and the precision compares well with that of commonly used RIA methods. The method appears suited to large numbers of samples, as in menstrual cycle monitoring.

Cross Reactions↗
PubMed1984

On-line computer analysis of chemiluminescent reactions, with application to a luminescent immunoassay for free cortisol in urine.

We interfaced a microcomputer on-line with a luminometer to acquire the light signal of chemiluminescent reactions from a photomultiplier and then compute significant parameters of light emission and kinetic "shape" indices. Using this system to study interferences from biological samples on the measurement of chemiluminescent reactions, we observed that such effects are usually associated with modifications of the shape of the light-emission kinetics. These results suggest that a simultaneous evaluation of the shape of a chemiluminescent reaction and the measurement of light emission can be combined to assess luminescent immunoassays as an internal control of the interferences in measurements of the chemiluminescent tracer. As an example of this approach, we developed and validated a luminescent immunoassay for free cortisol in diluted urine. Dextran-coated charcoal is used for bound-free separation.

Chemical Phenomena↗
PubMed1983

Prognostic role of estrogen receptor determination in breast cancer.

The authors report on 283 primary, non-metastatic, breast cancer cases consecutively referred after surgery and followed-up from a minimum of 10 months to a maximum of 3.5 years. All cases were studied according to the presence of estrogen receptors (ER). ER presence was correlated with age and menstrual status, with ER+ cases more frequent in older patients. No correlation was found between ER and nodal status. Prognosis was evaluated in terms of disease-free survival at 2 years (actuarial method). No correlation between ER and survival was evident for N- cases, whereas a better prognosis was recorded for ER+N+ patients compared to ER-N+, although the difference was not statistically significant. The observed results are compared with recent literature data and agree with other recent reports, which did not confirm the previously undiscussed statement regarding the prognostic role of ER determination. According to these studies and to the present study, the prognostic role of ER determination seems at least questionable and particularly the postoperative adjuvant treatment of ER-N- cases should be reconsidered.

Adult↗
PubMed1983

A solid phase chemiluminescent immunoassay (LIA) for testosterone glicuronide in diluted urines.

A chemiluminescent immunoassay (LIA) method in solid phase for the measurement of testosterone 17 beta-D-glicuronide (TG) in diluted urine is described, which utilizes as tracer a TG-isoluminol conjugate (TG-ABEI). An IgG fraction of antiserum of TG-BSA, has been passively adsorbed to the walls of polystyrene tubes. After the binding reaction the coated tubes were washed with buffer and the measure of chemiluminescence reaction was performed at high pH. The assay was validated in terms of specificity, accuracy, sensitivity and precision. The values obtained by chemiluminescence immunoassay were compared with that obtained by the RIA method, and the two methods agreed well (r = 0.95, n = 28). The assay method offers the advantage of speed and does not involve the use of radioisotopes or of a centrifugation step. Preliminary results show that the mean 24 h urinary TG excretion in a group of hirsute women is higher than in the control group, and decreases after suppression with dexamethasone for 1 month of therapy.

Cushing Syndrome↗
PubMed1983

Preparation and evaluation of steroid chemiluminescent tracers.

Six different isoluminol derivatives have been synthesized and evaluated as potential labels for conjugation to steroid molecules. The resulting steroid-chemiluminescent tracers have been investigated in terms of detection limit and affinity for the homologous antibody. The conjugation to the steroid molecule did not significantly affect the quantum yield of the chemiluminescent label. Consequently the detection limit was very similar using tracers with the same chemiluminescent label and different steroids and it was always at picomolar levels. The affinity of the chemiluminescent tracer versus the homologous antibody was evaluated using tritiated steroids as reference. The bridge and the chemiluminescent molecule could influence the affinity of the chemiluminescent tracer which could be higher, similar or lower than that of the tritiated steroid. In conclusion some isoluminol derivatives (i.e. ABEI or AEEI) can be considered as universal labelling compounds for steroids and their metabolites, because they possess a high light efficiency (similar to luminal itself) and favourable reaction conditions. Moreover the conjugation to the steroid molecule does not modify their chemiluminescent properties.

Animals↗
PubMed1983

Glucose-6-phosphate dehydrogenase activity and estrogen receptors in human breast cancer.

Both estradiol receptors and glucose-6-phosphate dehydrogenase activity (G6PDH) were measured on the same tissue sample from 143 patients who had undergone mastectomy for primary breast cancer. G6PDH activity in the estrogen receptor positive group (ER+) was higher than in the negative one (ER-). Moreover, the distribution of the enzymatic values in the ER+ group appeared to derive from two partially overlapped distributions. The authors suggest that only those ER+ tumors which show elevated G6PDH activity contain functional receptors. The determination of G6PDH activity at the time of mastectomy is proposed as an additional test in selecting those patients who would be likely to benefit from endocrine therapy.

Breast Neoplasms↗
PubMed1981

Evaluation of different progesterone-isoluminol conjugates for chemiluminescence immunoassay.

The effect of varying the length of the alkyl bridge linking the chemiluminescent label isoluminol to progesterone on the light yield and binding affinity of progesterone chemiluminescent-marker conjugates was investigated. For this purpose five different derivatives of isoluminol, aminoethyl isoluminol (AEI), aminoethylethyl isoluminol (AEEI), aminobutyl isoluminol (ABI), aminobutyl-ethyl isoluminol (ABEI) and aminoethyl-ethyl isoluminol (AHEI) were covalently linked through a peptide bond to progesterone-11 alpha -hemisuccinate (P-11-HS). The resulting progesterone chemiluminescent-marker conjugates were then evaluated as potential labels for the development of an immunoassay based on monitoring chemiluminescence. These conjugates were able to compete with tritiated progesterone for the binding sites of an antibody raised against progesterone-11 alpha-HS bovine serum albumin, and they showed higher affinity than unaltered progesterone. These conjugates produced light upon oxidation by a hydrogen peroxide-microperoxidase system. The chemiluminescent reaction was optimized in terms of pH, concentration of oxidant, catalyst and conjugate design. Under optimal conditions, all the conjugates were detectable at femtomolar levels. The lowest detection limit was obtained using P-11-HS-ABEI (0.1 fmol). These results indicated that immunoassay techniques based on chemiluminescence can be developed with these labels.

Animals↗
PubMed1981

Luminescent immunoassay (LIA) for progesterone in a heterogeneous system.

An immunoassay procedure for determination of progesterone in human plasma is described which utilizes chemiluminescence as the endpoint. The assay utilized progesterone-11-hemisuccinate-aminobutyl-ethyl-isoluminol (P-11-HS-ABEI) as the chemiluminescent marker conjugate and dextran coated charcoal for the separation of bound and free fractions of the ligand. An assay procedure for progesterone was established and validated in terms of sensitivity and precision, and assay results were compared with radioimmunoassay, using tritiated progesterone as the tracer. The two methods agreed well (n=35, r=0.96). The most important advantage of this assay is the elimination of problems inherent in the use of radioactive materials.

Azides↗