PubMed Health⌕ Search

Biomedical subjects

A Clerico

Publications and source records attributed to A Clerico.

At least 145 records · Page 8Linked to original sources
PubMed1982

Free-cortisol assay by immunoextraction: comparison with an equilibrium dialysis procedure.

We describe a new method for directly determining the apparent free cortisol concentration in plasma samples by use of an antibody-coated test-tube RIA. Buffer-diluted plasma or standard serum is added to antibody-coated test tubes, incubated at 4 degrees C for 4 h, and the solutions are aspirated. 125I-labeled cortisol is added to each tube and incubated for 3 h at 4 degrees C. Then the insides of the tubes are washed and their radioactivities counted. The standard curve is in terms of free cortisol, the standard serum solutions having been measured with an equilibrium dialysis procedure. Plasma samples (n = 155) from normal subjects and from various patients, measured with the new immunoextraction method and the equilibrium dialysis technique, gave results that correlated well (r = 0.847, p less than 0.001). Results by this direct RIA also correlate well with the clinical adrenocortical status of patients for whom data on total plasma cortisol may be misleading. This simple, easy RIA is suited to be the routine method for free cortisol in plasma.

Anorexia Nervosa↗
PubMedDate not supplied

Association of near-diploid DNA content and N-myc amplification in neuroblastomas.

Seventeen neuroblastomas at different clinical stages were analysed for their N-myc copy number and flow cytometrically determined DNA content. Aneuploidy was found in 11 patients (65 per cent), whereas the remaining were near-diploid. N-myc amplification was found significantly (P less than 0.05) confined to near-diploid tumors (3 out of 6 cases). This finding indicates a very selective mechanism of oncogene amplification which is independent of gross chromosomal imbalance and limited to specific loci in the human genome. Association of near-diploidy and age at diagnosis older than 24 months was also demonstrated (P less than 0.05). Thus, flow cytometric analysis of DNA content together with N-myc gene dosage allowed us to distinguish two different subsets of neuroblastoma tumors: the first one aneuploid, with single-copy N-myc, usually observed in patients younger than 24 months with localized or IV-S clinical stages; the second one near-diploid, with frequent N-myc amplification, usually observed in patients older than 24 months with advanced clinical stages.

Child↗
PubMedDate not supplied

Colorimetric versus radioimmunological measurement of glycated and non-glycated serum albumin after affinity chromatography.

Affinity chromatography by m-aminophenylboronic acid has been proposed for routine measurement of glycated albumin. We assayed glycated and non-glycated fractions of serum albumin (HSA) eluted by affinity chromatography columns by both a specific RIA method for the human serum albumin (HSA) and by a colorimetric method. Sixteen diabetic patients presented a significantly higher percentage of glycated-HSA than 7 control subjects with both methods, and a strong correlation was found between the values obtained with the two methods. RIA was able to detect a significant concentration of glycated-HSA in all normal subjects, while the colorimetric method was not. The accuracy of separation between the glycated and non-glycated fractions of albumin was tested using [14C]glucose as tracer. When [14C]glycated-HSA purified by Sephadex G25 filtration was chromatographed using the m-aminophenylboronic acid, only 5.3% of the total 14C-radioactivity present in the solution was recovered in the bound fraction, while 44.0% was eluted in non-protein-bound fraction and 54.7% was retained in the column. Our findings confirm that affinity chromatography by m-aminophenylboronic acid can be a useful tool in the monitoring of short glycemic control of diabetic patients. Our data also indicate that the affinity chromatography with m-aminophenylboronic acid does not accurately discriminate between glycated and non-glycated fraction of HSA.

Adult↗
PubMedDate not supplied

Progressively elevated levels of biologically active (free) cortisol during pregnancy by a direct radioimmunological assay of diffusible cortisol in an equilibrium dialysis system.

The measurement of free cortisol would be preferable with respect to the total hormone content, since it yields more reliable information about the plasma levels of the biologically active cortisol. We have developed a new method for the determination of the apparent free plasma cortisol concentration (AFCC) by means of direct radioimmunological measurement of dialyzed cortisol. The AFCC was measured in 23 plasma pools obtained from normal pregnant women at various gestational times and in 18 nonpregnant women. The mean AFCC was 19.5 +/- 7.1 ng/ml in pregnant women and 9.0 +/- 6.2 ng/ml in nonpregnant women (p less than 0.005). The percent of free cortisol (%FC) showed a progressive increase during pregnancy reaching the lower limits of the normal range at the third trimester. However, the mean of %FC was significantly lower (p less than 0.005) in pregnant women than in nonpregnant women. Our data show a progressive increase of biologically active cortisol during pregnancy.

Dialysis↗
PubMedDate not supplied

Chemotherapy in low-grade astrocytoma management.

The role of chemotherapy (CHT) in the management of low-grade astrocytoma (LGA) is still unclear. Nineteen children with nonresectable symptomatic LGA were treated with carboplatin (CBDCA) and etoposide (E). There were 15 newly diagnosed cases and 4 were relapses; 6 of the children were under 5 years old. In all children radiological evaluation by CT scan and/or MRI was performed after four courses of CHT. We observed complete response (CR)+ minor response (MR) in 37% of these cases and an improvement in neurological symptoms in 63%. Radiological evaluation performed in 6 patients who received CHT for longer periods (8-12 courses) showed major responses (CR+PR) in 67%. Local radiotherapy (40 Gy) was administered after CHT in 14 cases, but in 3 of these radiotherapy was delayed for 2 years. Five patients did not receive radiotherapy. The overall survival was 58% after an average follow-up of 60 months. All patients with brain stem tumors died of progressive disease even though 3 of these had shown clinical improvement after chemotherapy. In conclusion, in the treatment of nonresectable symptomatic LGA, CHT with CBDCA associated with E can be used to postpone radiotherapy in young children and even to avoid radiotherapy in some cases.

Adolescent↗
PubMedDate not supplied

Oxidative damage to RBC membranes and pentose phosphate shunt activity in hemodialysis patients after suspension of erythropoietin treatment.

During follow-up of anemic hemodialysis patients (HDP) treated with recombinant human erythropoietin (rHuEpo), it was noticed that in five HDP, some time after suspension of rHuEpo, hemoglobin (Hb) levels remained at acceptable levels. A metabolic block of the pentose phosphate shunt (PPS) has been described in HDP, which leads to increased oxidative damage of red blood cell (RBC) membranes and increased susceptibility to hemolysis. The increased production of short-chain fatty aldehydes, including malonyldialdehyde (MDA), is an appropriate index of oxidative damage. This study aimed to verify whether the maintenance of acceptable levels of Hb was related to a change in RBC membrane oxidative damage and pentose phosphate shunt activity. In the five HDP in question who required rHuEpo (150 U/kg/week) for severe anemia (Hb = 7.48 +/- 0.95 g/dl), after a stable level of Hb > 10 g/dl was reached for at least 1 month, rHuEpo treatment was stopped. Hb levels remained adequate (Hb = 10.68 +/- 0.77 g/dl) after 14.6 +/- 7.64 months. The oxidative damage was evaluated by measuring RBC MDA (microgram/ml packed RBC) basal levels, and PPS activity by measuring MDA levels after incubation with ascorbate and cyanide (delta % RBC MDA production). Ten anemic HDP not treated with rHuEpo were used as controls (Hb = 8.12 +/- 1.32 g/dl). It was found that the maintenance of adequate levels of serum Hb after suspension of rHuEpo therapy is related to a decrease in RBC membrane oxidative damage (RBC MDA HDP = 2.40 +/- 0.41 vs. RBC MDA controls = 18.23 +/- 6.56; P < 0.005) in consequence of the normalization of pentose phosphate shunt activity.

Aged↗