Search PubMed⌕ Search

Biomedical subjects

A Albertini

Publications and source records attributed to A Albertini.

At least 163 records · Page 9Linked to original sources
PubMed1987

Characterization of human ferritin H chain synthetized in Escherichia coli.

We have inserted the coding region of the cDNA for human ferritin H chain into the expression vector pEMBLex2. The plasmid obtained is able to direct the synthesis of the ferritin H chain in Escherichia coli up to a concentration of 15% of total soluble proteins. All expressed subunits are found correctly assembled in the complete ferritin molecule, which can be easily purified. We have shown that the ferritin synthesized in E. coli has an Mr, electrophoretic mobility, and thermal stability similar to natural human isoferritins and is recognized by monoclonal antibodies specific for the H, but not by those for the L human ferritin chains.

Cloning, Molecular↗
PubMed1987

Reproducibility and reliability of first pass radionuclide ventriculography with Au-195m. Validation of Au-195m radionuclide ventriculography.

Au-195m is a radio-isotope with an ultra-short half-life with which multiple sequential evaluations of ventricular function can be made. In order to evaluate the reliability and reproducibility of analyses of overall and regional ventricular function by radio-isotope ventriculography with Au-195m we studied 10 healthy volunteers and 12 patients with coronary artery disease. Each subject underwent 4 first-pass studies: 1 with Tc-99m and, 10 minutes later, 3 with Au-195m (2 basal studies separated by 3-5 minutes interval and, 10 minutes later, 1 after s.l. nitroglycerin administration). Regional wall motion was analyzed and ejection fraction and peak count rate were determined in each test. Our study showed that the ejection fraction obtained with Au-195m was reproducible (r = 0.98) and correlated well with the ejection fraction determined by using Tc-99m (r = 0.98). The values of the peak count rate obtained with Tc-99m were higher than those obtained with Au-195m. Due to the specially designed collimator and the technical characteristics of the gamma-camera we used, we were able to record sufficiently high count-rates to evaluate regional wall motion, and this analysis was also found to be reliable and reproducible. After s.l. nitroglycerin administration, normal volunteers showed a significant increase of ejection fraction in comparison with basal acquisitions (p less than 0.05), while a wide range of responses was observed in the group of patients with coronary artery disease. We conclude that radio-isotope ventriculography with Au-195m is reliable and reproducible and could be a valid method of monitoring rapid variations induced in overall and regional left ventricular function.

Adult↗
PubMed1987

Improved procedure for determining glutathione in plasma as an index of myocardial oxidative stress.

Glutathione plays an important role in the detoxification processes of electrophilic metabolites of xenobiotics and oxygen free radicals, such that release of reduced and oxidized glutathione into the plasma is considered a reliable index of oxidative stress. However, reduced glutathione in plasma undergoes spontaneous autoxidation, with mixed disulfide formation. We developed a new, simple, quick method to overcome this problem by treating the blood, immediately after collection, with thiol reagents. We add 5,5'-dithiobis(2-nitrobenzoic acid) and N-ethylmaleimide to the blood before determination of total and oxidized glutathione, respectively. We find the proposed assay useful for investigating oxidative stress in clinical situations.

Adult↗
PubMed1987

Accuracy and reproducibility of the assessment of the global ejection fraction using 195mAu and a single-crystal digital gamma camera: influence of collimator design.

A sequence of RAO first-pass studies (first with 99mTc and then twice with 195mAu) was performed in 18 normal volunteers and in 12 CAD patients using two different types of collimator for medium energy: a standard collimator (MEMS) and a special high-sensitivity collimator (MEHS). The following data were compared: the peak count rate, the net LV end-diastolic counts and the LVEF. Using MEMS the end-diastolic counts acquired were so low (12% of 99mTc average value) that EF standard deviation had a mean value of 0.061 (range 0.045-0.081). With MEHS the following results were obtained: 1. the peak count rate and LV net end-diastolic counts with 195mAu were 55% and 50% respectively, of 99mTc values; 2. a good correlation was shown between LVEF values either with 99mTc and 195mAu (r = .97), or with 195mAu sequential studies (r = .98).

Adult↗
PubMed1986

Myocardial recovery during post-ischaemic reperfusion: effects of nifedipine, calcium and magnesium.

We studied the effects of various interventions introduced at the time of post-ischaemic reperfusion on mechanical activity, tissue and mitochondrial calcium, mitochondrial function and tissue ATP and CP of isolated perfused rabbit hearts. These interventions were: nifedipine, low calcium (0.75 mM, 0.15 mM and 0.05 mM), high magnesium (15 mM) and high magnesium (15 mM) with low calcium (0.75 mM). Ischemia was induced by abolishing coronary flow for 60 min, followed by 30 min of reperfusion. The results indicate that nifedipine when given during reperfusion had no protective effect, whilst it was beneficial when administrated before ischaemia. Lowering calcium content of the perfusate during reperfusion may be advantageous, depending on the degree of calcium reduction. Reperfusion with high magnesium reduced the mitochondrial calcium overload and maintained the mitochondrial ATP-producing capacity but failed to modify the increase of tissue calcium and of diastolic pressure. Lowering calcium content in the presence of high magnesium resulted in better protection. These data suggest that the conditions of reperfusion may influence the capacity of myocardial recovery.

Adenosine Triphosphate↗
PubMed1986

Aminophylline blood levels with concomitant erythromycin therapy in relapsed chronic obstructive lung disease.

Sixty patients affected by chronic obstructive lung disease (COLD) in relapse were treated with erythromycin and aminophylline. The patients were divided into three groups: Group A received 2 g erythromycin and 1200 mg aminophylline daily, and Group B and C received 2 g erythromycin with respectively 800 mg and 600 mg of aminophylline daily, administered as two oral doses in each case. On day 5 of therapy, we chromatographically evaluated aminophylline in a serum sample taken two hours after morning drug administration which corresponds to the peak plasma level. We also evaluated certain biohumoral, microbiological, radiological and electrocardiographic parameters both before and after therapy. Statistical analysis of the data was performed by the Student's t test. Our data confirm that 600-800 mg oral aminophylline administered simultaneously with erythromycin induce an improvement in the respiratory function of patients with relapsed COLD without elevating blood aminophylline levels and without side-effects.

Aged↗
PubMed1986

Components of variance analysis of data produced in a national quality-control survey of radioimmunoassays of thyroxin, triiodothyronine, thyrotropin, prolactin, and progesterone.

Data collected in a collaborative survey for radioimmunoassays have been studied by using analysis of variance to estimate the within-kit (CVw.kit) and the between-kit (CVb.kit) components of the total variability (CVT). This analysis has been applied to the results for triiodothyronine, thyroxin, thyrotropin, prolactin, and progesterone produced by 80-150 laboratories that assayed blind, replicate samples. Total variability was lowest in the thyroxin assay (CVT = 10.9%), associated with a very close between-kit agreement (CVb.kit = 4.0%); in the triiodothyronine assay, on the other hand, the large between-kit component (CVb.kit = 10.1%) increased the total variability to 16.1%. In the prolactin assay the CVT of 19.3% included 17.5% CVw.kit and 8.1% CVb.kit. Assays for thyrotropin and progesterone involve analyses of two pools at different hormone concentrations. The CVb.kit component was very high in the low-concentration pool, both for thyrotropin (25.1%) and progesterone (45.2%); in the higher-concentration pool it decreased to 8.3% for thyrotropin but remained high (21.6%) for progesterone. Applying analysis of variance to the triiodothyronine and thyroxin data obtained by different laboratories using the same kit showed that most kits yielded significantly different measurements when used in different laboratories.

Analysis of Variance↗
PubMed1985

Immunological reactivity of serum ferritin in patients with malignancy.

Serum ferritin has been suggested as a tumor marker in the diagnosis of certain malignancies and for following the activity or dissemination of the malignant process. Since neoplastic tissues generally contain more acidic isoferritins than their normal tissue counterparts, it has also been suggested that the specific assay of such isoferritins in serum may be of particular value in the diagnosis of malignancy. In this work, we have evaluated ferritin concentration in the serum of normal subjects and patients with acute nonlymphocytic leukemia, Hodgkin's disease, breast cancer and lung cancer by simultaneously using three different immunoassays: an immunoradiometric assay based on polyclonal antibodies against human liver (basic, L-subunit rich) ferritin, a radioimmunoassay based on polyclonad antibodies against HeLa cell (acidic, H-subunit rich) ferritin, and an immunoradiometric assay based on the monoclonal antibody 2A4 raised against human heart (acidic, H-subunit rich) ferritin. Most of the patients studied had increased values for liver-type ferritin in the absence of increased iron stores. Binding of serum ferritin to concanavalin A did not prove to be useful in distinguishing a tumor-specific basic isoferritin. The HeLa ferritin assay was found to be less specific than the heart ferritin assay in the detection of acidic isoferritins, and did not provide any advantage over the liver assay in detecting the increased levels of serum ferritin associated with malignant disease. Heart-type ferritin was found in one-fifth of normal sera and 64% of sera from patients with malignancy. Values were very low compared with those for basic ferritin, ranging from less than 0.1 to 17% of total serum ferritin (geometric mean value 1.3%) in patients with malignancy. These findings indicate that at present there is little application for serum ferritin immunoassays based on antibodies to HeLa cell or heart ferritin in the diagnosis or monitoring of malignant disease. This seems to be due to the presence in human serum of biding factors which are responsible for the rapid clearance of acidic isoferritins from the circulation. The serum concentration of basic ferritin, however, can be useful in the diagnosis and management of some malignancies, and it is possible that studies on cell isoferritins can be important in biologic monitoring of neoplastic disorders. It should also be noted that the increased levels of serum ferritin found in patients with malignancy can exert adverse effects on the host immune response and perhaps an inhibitory effect on hematopoiesis.

Antibodies, Monoclonal↗
PubMed1985

Changes in the cardiac glutathione status after ischemia and reperfusion.

In the isolated and perfused rabbit heart ischemia induced a rapid decline of contractility, associated with a reduction of the content of tissue GSH with no significant changes in GSSG. Reperfusion induced a small recovery of contractility, a substantial release of total glutathione and a further decrease in the content of tissue GSH with a significant increase of tissue GSSG. Glutathione reductase and glutathione peroxidase activities were not affected by ischemia and reperfusion. This study suggests a possible role for glutathione in the determination of functional damage induced by myocardial ischemia and reperfusion.

Animals↗
PubMed1985

Computerized analysis of equilibrium radionuclide ventriculography time-activity curve in the assessment of left ventricular performance: comparison of two methods.

Two methods for the analysis of left ventricle time-activity curve (TAC) of equilibrium gated ventriculography were compared in three groups of subjects [8 controls, 13 patients with coronary artery disease (CAD), 11 patients with myocardial infarction (MI). The first method was based on third-degree polynomial fitting, the second on Fourier analysis. The following parameters were calculated: peak ejection rate (PER), peak filling rate (PFR), time to PER and PFR, and filling fraction at the first third of diastole. A preliminary study of changing values of PER and PFR and of the mean error with increasing number of harmonics summed in order to obtain the best fitting of TAC demonstrated that beyond the sum of the first four harmonics there was no further significant improvement. The advantages of Fourier analysis are as follows: it is independent of the operator and fits only one function to the whole cardiac cycle; it requires less computer time; it provides better differentiation between controls and CAD patients. All of the 13 CAD patients had abnormal PFR on Fourier analysis, only 9 on polynomial analysis. At rest, 9 of the CAD patients had wall motion abnormalities, while only two had an abnormal ejection fraction.

Adult↗