Biomedical subjects

G Farace

Publications and source records attributed to G Farace.

4 recordsLinked to original sources

PubMed2002

Strategic issues in reliable sensing.

Amperometric enzyme biosensors must possess two important characteristics if they are to be successfully utilised as reliable monitoring devices. They must exhibit linearity over concentrations relevant to the target analyte, and they must avoid contamination, adverse reactions with the sample matrix response to interferents that react directly at the polarised working electrode surface. Covering polymeric membranes have provided a useful route to overcoming these problems. This report summarises successful modulation of membrane bulk as well as surface properties using surfactant-loaded diffusion limiting PVC and phenolic membranes, and the possible exploitation of direct response conducting poly (pyrrole) membrane loaded with affinity molecules through impedance spectroscopy.

Biosensing Techniques↗

PubMed2002

Reagentless biosensing using electrochemical impedance spectroscopy.

The use of electrochemical impedance spectroscopy (EIS) and the conducting polymer, poly (pyrrole), as an integrated recognition and transduction system for reagentless biosensor systems was demonstrated with two different systems. The first system being an immunoassay for detection of luteinising hormone (LH) with the antibody being entrapped with in the poly (pyrrole) matrix and the second, a construct for DNA hybridisation discrimination able to differentiate single- and double-stranded DNA based on the interaction of the DNA with poly (pyrrole).

Biosensing Techniques↗

PubMed2001

Molecular patterning on carbon based surfaces through photobiotin activation.

We have demonstrated the site-specific adhesion of photobiotin as a method of producing protein micropatterns. These patterns were created by the selective UV irradiation of a thin film of deposited photobiotin. The UV activated areas of photobiotin were then developed using fluorescently labelled avidin. The size of pattern produced is an order of magnitude smaller than those previously reported by this method. The patterns were characterised, using atomic force microscopy (AFM) to determine their microstructure. It was found that the AFM could discriminate between the areas of protein immobilised to the surface through the activated photobiotin, and the bare substrate surface where the inactivated photobiotin had been removed during the washing process. The potential of these patterns as sensing surfaces is demonstrated through the creation of a spatially patterned immunosensing surface. In this case, a biotinylated antibody was bound to the surface and the pattern developed using a second antibody specific to the immobilised biotinylated antibody. This technique could thus provide a simple and efficient method of producing high density immunoassay systems.

Journal Article↗

PubMed2001

[Pancreatic tumor: an unusual presentation of an occult breast carcinoma].

A case of cholestasis due to a synchronous pancreatic head metastasis from an occult lobular breast carcinoma is presented. The patient had a clinical and radiological picture compatible with a pancreatic head primary tumor with cholestasis and ascites. Ultrasonographically guided fine needle aspiration cytology demonstrated a metastatic breast lobular cancer (positive for cytokeratin AE1 and AE3, cytokeratin 7 and epithelial membrane antigen and negative for cytokeratin 20, CA 19.9, CA 125, CEA and estrogenic receptors). The same cytologic findings were observed in skin and subcutaneous armpit nodules. Clinical and radiological breast examination was unable to demonstrate any tumor in the breast. Pancreatic metastases are rare events and the majority of them are secondary to renal and lung cancer and rarely to breast cancer. In these latter cases, metastases are usually disclosed after a disease-free interval of months or years between primary tumor resection and recognition of the pancreatic tumor. Synchronous presentation is extremely rare. Metastases of epithelial origin are uncommon in pancreas and generally are first misdiagnosed as primary pancreatic cancer. Fine needle aspiration is a useful tool for the differential diagnosis in patients with widespread disease.

Biopsy, Needle↗