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Biomedical subjects

L Perna

Publications and source records attributed to L Perna.

14 recordsLinked to original sources
PubMed2003

Sample cleanup by on-line chromatography for the determination of Am in sediments and soils by alpha-spectrometry.

A novel sample cleanup procedure for the Am determination in environmental samples by alpha-spectrometry is described. The method is based on the use of three analytical chromatographic columns. TEVA-Spec. from Eichrom has been packed in an analytical chromatographic column to carry out the lanthanide/actinide separation. A CS5A mixed-bed column from Dionex was used to separate Am from lanthanide impurities and other actinides. A TCC-II column from Dionex was used to connect the TEVA to the CS5A and act as a preconcentrator column for the trivalent ions. The behavior of the columns was studied by coupling the chromatograph to an ICPMS detector. A chromatographic fraction has been used for sample preparation for alpha-spectrometric determination of 241Am. The analytical procedure has been validated with certified reference materials (sediment and soil) and was applied to sediment core samples from the Irish Sea and compared with the classical radiochemical separation of Am.

Americium↗
PubMed1989

Clinical relapse in systemic lupus erythematosus: correlation with antecedent elevation of urinary free light-chain immunoglobulin.

This paper reports preliminary evidence suggesting that measurements of free light-chain Ig (FLIg) in urine may represent quantitative markers of in vivo polyclonal B-cell activation. Thus, longitudinal levels of urinary FLIg in patients with systemic lupus erythematosus (SLE) may be used to track or monitor the in vivo immunopathologic B-cell activity of SLE and be helpful in predicting a disease relapse. Our findings showed that dramatic rises in urinary FLIg occurred during asymptomatic intervals that preceded by 4-8 weeks the first symptomatic signs of acute SLE relapse. These results suggest that a sizable lead time may exist between the occurrence of immunopathologic B-cell stimulation and the resultant symptoms and tissue damage of immune complex-induced acute inflammation. In these studies the measurement of urinary FLIg was accomplished by an indirect method using ng-sensitive radioimmunoassays (RIAs) that measured isotypic IgG, IgA, IgM, total kappa-Ig, and total lambda-Ig. As a control for the assessment of renal tubular function and the excretion of low molecular weight proteins in SLE patients, longitudinal measurements of beta-2-microglobulin (B2M) and lysozyme were made using a novel solid-phase 3H-biotin RIA technique.

Adult↗
PubMed1979

[Short-term and average-term automatic control of re-entry arrhythmias].

The AA. described an external stimulator to be utilized instead of invasive pharmacological treatment, as a short and middle-time therapeutic approach to re-entry tachycardia, in Departments of cardiology. The device must be connected with an electrode placed in atrium or in coronary sinus or in ventricle, according to individual request. A frequency discriminant device recognizes tachycardia and activates automatic scanning stimulator, synchronized on R or P waves, with progressive 5 msec stop delay; tachycardia interruption zone is automatically individuated. Stimulation has an automatic stop when tachycardia is interrupted; in case of persistent tachycardia scanning-function cycle will star again automatically. The device, which can be programmed for a simple or a double impulse emission, is equipped with a demand stimulator working if post-tachycardia asystole is present. Frequency discriminant device activates the scanning function beyond a defined threshold which can be varied within a wide range of frequencies.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Radiotherapy treatment verification.

During a radiotherapy treatment, a dosimetric verification or a geometric localization can be done, in order to assess the quality of the treatment. The dosimetric verification is generally performed measuring the dose at some points inside (natural cavities) or outside the patient, and comparing it to the dose at the same points calculated and predicted by the treatment planning system. This can be done either with thermoluminescent or diodes dosimeters or with ionization chambers. The geometric localization can be done acquiring a portal image of the patient. Portal imaging can be performed either with films placed between metallic screens, or with an electronic portal imaging device such as fluoroscopic systems, solid state devices or matrix ionization chamber systems. In order to assess possible field placement errors, the portal images have to be compared with images obtained with the simulator in the same geometric conditions and/or with the digitally reconstructed radiograph (DRR) obtained with the treatment planning system. In particular, when using matrix ionization chamber systems, the portal images contain also information regarding the exit dose. This means that this kind of imaging device can be used both for geometric localization and for dosimetric verification. In this case, the exit dose measured by the portal image can be compared with the exit dose calculated and predicted by the treatment planning system. Some "in-vivo" applications of this methodology are presented.

Humans↗