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Biomedical subjects

A Celi

Publications and source records attributed to A Celi.

22 records · Page 2Linked to original sources
PubMed1988

A computer-based method for on-line acquisition and analysis of bronchial challenge test.

We developed a computer program for the optimization and management of data collection in order to compute the change of forced expiratory volume in the first second (delta FEV1), provocative doses and to plot the dose-response curve for bronchial challenge test. Doses of methacholine are entered via the keyboard and forced vital capacity (FVC) with the highest FEV1 value obtained in each step is selected. When the imposed threshold of response has been reached, doses of administered methacholine and corresponding spirometric parameters are displayed and printed. Dose-response relationships are analysed: the increase of delta FEV1 for each unit of metacholine is computed in the interval between the two doses where delta FEV1 reached one of the imposed values (i.e. 15% or 20% or 30%). Finally spirometric values, dose-response curve and provocative doses are shown in a print-out. Computer values of provocative doses are higher than those obtained manually. This difference may be ascribed to the incorrect manual linear extrapolation. In conclusion the computer program is able to reduce consistently the time spent to analyze data from bronchial challenge test and allows a more precise determination of provocative doses by avoiding also inter-intra individual errors.

Asthma↗
PubMed1987

Comparison of algorithms for determining the end-point of the forced vital capacity maneuver.

The criteria of the American Thoracic Society (ATS) for determining the end-point of the forced vital capacity (FVC) maneuver were compared with an algorithm employed by a computer system (Hewlett-Packard), which yields a later end-point. The 150 subjects tested were divided into five groups of 30 on the basis of the following spirometric diagnoses: normal; small airways' obstruction (SAO); mild airways' obstruction (MAO); severe chronic obstructive pulmonary disease (COPD); or restrictive disease. The subjects performed a minimum of three maneuvers according to ATS standards, and the flow-volume curves with the greatest sum of FVC and forced expiratory volume in one second (FEV) were chosen for analysis by the two algorithms. Hewlett-Packard (HP) values for FVC and FVC time were always higher than the corresponding ATS values, and the HP values for flows were always lower than the corresponding ATS values. The higher differences were observed in the SAO group. In the group with severe COPD, high FVC differences and low flow differences were observed; on the contrary, in the restrictive group, low FVC differences and high flow differences were present. These results, in addition to the different location of the FVC end point, may be explained by the different morphology of the flow-volume curves. In conclusion, the ATS algorithm caused a systematic underevaluation of FVC and a systematic overevaluation of flows, which cause practical consequences only in the SAO group. In fact, 28 percent (17/60) of the subjects with SAO characteristics were considered "normal" using ATS criteria for the end-point.

Adult↗
PubMedDate not supplied

Detection of distinct isoform patterns of the beta-amyloid precursor protein in human platelets and lymphocytes.

Cerebral deposition of the amyloid beta-protein (A beta P), approximately 40 residue fragment of the integral membrane protein, beta-amyloid precursor protein (beta APP), has been implicated as the probable cause of some cases of familial Alzheimer's disease (AD). The parallels between A beta P deposition in AD and the deposition of certain plasma proteins in systemic amyloid diseases has heightened interest in the analysis of beta APP in circulating cells and plasma. Here, we describe distinct isoform patterns of beta APP in peripheral platelets and lymphocytes. PCR-mediated amplification of mRNA from purified platelets demonstrated the expression of all three major beta APP transcripts (beta APP770,751,695). The full-length, approximately 140 kDa form of beta APP751,770 was detected in membranes of resting and activated platelets but very little immature, approximately 122 kDa beta APP751,770 was found, suggesting a different processing of beta APP in platelets than that described in a variety of cultured cells and tissues. Platelets stimulated with thrombin, calcium ionophore, or collagen released the soluble, carboxyl-truncated form of beta APP (protease nexin-II), but no evidence for the shedding of full-length beta APP associated with platelet microparticles was found, in contrast to previous reports. As a positive control marker for microparticles, the fibrinogen receptor subunit, GPIIIa, was readily detected in platelet releasates. Resting and activated platelets contained similar amounts of the approximately 10 kDa carboxyl terminal beta APP fragment that is retained in platelet membranes following the constitutive cleavage of protease nexin-II. Nonstimulated peripheral B and T lymphocytes contained small amounts of membrane-associated mature and immature beta APP751,770. The potentially amyloidogenic full-length beta APP molecules present in circulating platelets and lymphocytes but not in microparticles could serve as a source of the microvascular A beta P deposited during aging and particularly in AD.

Adult↗