Biomedical subjects

Manuel Ventura

Publications and source records attributed to Manuel Ventura.

3 recordsLinked to original sources

PubMed2004

A mass spectrometry plate reader: monitoring enzyme activity and inhibition with a Desorption/Ionization on Silicon (DIOS) platform.

A surface-based laser desorption/ionization mass spectrometry assay that makes use of Desorption/Ionization on Silicon Mass Spectrometry (DIOS-MS) has been developed to monitor enzyme activity and enzyme inhibition. DIOS-MS has been used to characterize inhibitors from a library and then to monitor their activity against selected enzyme targets, including proteases, glycotransferase, and acetylcholinesterase. An automated DIOS-MS system was also used as a high-throughput screen for the activity of novel enzymes and enzyme inhibitors. On two different commercially available instruments, a sampling rate of up to 38 inhibitors per minute was accomplished, with thousands of inhibitors being monitored. The ease of applying mass spectrometry toward developing enzyme assays and the speed of surface-based assays such as DIOS for monitoring inhibitor effectiveness and enzyme activity makes it attractive for a broad range of screening applications.

Enzyme Inhibitors↗

PubMed2004

High-throughput preparative process utilizing three complementary chromatographic purification technologies.

A high-throughput process was developed in which wells in plates generated from parallel synthesis are automatically channeled to an appropriate purification technique using analytical data as a guide. Samples are directed to either of three fundamentally different preparative techniques: HPLC with UV-triggered fraction collection, supercritical fluid chromatography (SFC) with UV-triggered fraction collection, or HPLC with MS-triggered fraction collection. Automated analysis of the analytical data identifies the product compound mass and creates work lists based on chromatographic properties exhibited in the data so that each preparative instrument cherry picks the appropriate list of samples to purify when a preparative-scale plate is loaded.

Chromatography, High Pressure Liquid↗

PubMed2003

Relationship between Prostatic Specific Antigen (PSA) and volume of the prostate in the Benign Prostatic Hyperplasia in the elderly.

Increase of the Prostatic Specific Antigen (PSA) is a non-invasive, sensitive and specific markers for prostatic diseases, including prostatic cancer. However, age-related Benign Prostatic Hyperplasia (BPH), as well as prostatitis, may at the same time alter PSA values. The aim of this study was to evaluate the relationship between ageing and PSA, and whether age-specific upper normal limits of PSA should be considered for elderly patients. We evaluated 569 consecutive subjects aged 60 years or more (mean age 74.2 years) who were free from malignant prostatic disease, without clinical evidence of prostatic phlogosis and who were not receiving PSA levels affecting drugs. All patients underwent Digital Rectal Examination (DRE) and Trans-Rectal Ultrasonography (TRU), with determination of the three prostatic diameters, the Maximum Adenoma Diameter (MAD) and calculation of the prostatic volume (PV) by the ellipsoid formula. PSA was determined in all patients before DRE and TRU, and the PSA free ratio was determined in those with total PSA values >4 ng/ml. The PSA density was calculated according to the formula PSA/PV. One hundred and seventy-nine subjects (31.6%) were found to have PSA values >4 ng/ml: among them, 26 (14.5%) had values exceeding 10 ng/ml. Age was slightly correlated with PV (P<0.05), but not with PSA values. On the contrary, PSA values were strongly related with PV and MAD (P<0.01 both). Mean PSA-free ratio was 16.3+/-6.0% and most of patients had values in the so-called 'grey zone' of discrimination between benignity and malignity. Elevated PSA levels are common in older subjects without evidence of prostatic malignancy; PSA values are poorly affected by age itself and strongly correlated with increasing PV. These results suggest the possibility to consider as indicative of benignity PSA values between 4 and 10 ng/ml, when these values are associated with relevant increase of PV and with PSA-free ratio greater than 10%.

Age Factors↗