Development of a PCR-free electrochemical point of care test for clinical detection of methicillin resistant Staphylococcus aureus (MRSA).

An MRSA assay requiring neither labeling nor amplification of target DNA has been developed. Sequence specific binding of fragments of bacterial genomic DNA is detected at femtomolar concentrations using electrochemical impedance spectroscopy (EIS). This has been achieved using systematic optimisation of probe chemistry (PNA self-assembled monolayer film on gold electrode), electrode film structure (the size and nature of the chemical spacer) and DNA fragmentation, as these are found to play an important role in assay performance. These sensitivity improvements allow the elimination of the PCR step and DNA labeling and facilitate the development of a simple and rapid point of care test for MRSA. Assay performance is then evaluated and specific direct detection of the MRSA diagnostic mecA gene from genomic DNA, extracted directly from bacteria without further treatment is demonstrated for bacteria spiked into saline (10(6) cells per mL) on gold macrodisc electrodes and into human wound fluid (10(4) cells per mL) on screen printed gold electrodes. The latter detection level is particularly relevant to clinical requirements and point of care testing where the general threshold for considering a wound to be infected is 10(5) cells per mL. By eliminating the PCR step typically employed in nucleic acid assays, using screen printed electrodes and achieving sequence specific discrimination under ambient conditions, the test is extremely simple to design and engineer. In combination with a time to result of a few minutes this means the assay is well placed for use in point of care testing.

Langer's axillary arch: anatomy, embryological features and surgical implications.

Langer's arch is identified in up to 7% of axillary explorations; in a three-month period we identified three individuals among forty-six patients undergoing axillary surgery with this abnormality. Langer's arch is a muscular-tendinous structure that usually extends from latissimus dorsi to pectoralis major muscle. The purpose of this article is to describe the embryological derivation of this muscular variant from the panniculus carnosus and to define its anatomical features. The clinical implications both symptomatically and as an unexpected finding during axillary dissection, are also discussed.

Outcome and long term results of surgical resection for gastrointestinal stromal tumors (GIST).

BACKGROUND AND AIMS: Gastrointestinal Stromal Tumors (GIST) are rare; diagnosis and prognosis of these tumors are often complex. We present short and long term results of surgical resection for GIST at the Department of Surgery, University of Insubria, during a period of 14 years. MATERIAL AND METHODS: All patients' data, tumor characteristics, surgical procedure and survival data were analyzed retrospectively. Tumors were divided in risk classes using a new classification proposed by Fletcher, based on tumor size and number of mitosis. RESULTS: From 1987 to 2001 19 patients underwent surgical resection for GIST. Stomach was the most common site of localization. Complete resection was achieved in 78.9 % cases, while in 21.1% radical resection was not possible. The mean tumor size was 8.4 cm (1.2-30 cm): < 5 cm diameter in 11/19 cases (58%), 5-10 cm in 4/19 (21%) and > 10 cm in 4/19 (21%). Mitotic count was < 10/50 HPF in 68.5 % (13/19) and > 10/50 in 31.5 % (6/19). Using Fletcher's classification, tumors were divided in very low (8/19, 42.2 %), low (3/19, 15.8 %), intermediate (4/19, 21%) and high risk (4/19, 21%). The 5 years overall survival was 63 % and 34 % respectively with a statistically significant difference between tumors < 5cm and > 10 cm in diameter and between complete and incomplete resection. High risk tumors have a significantly shorter survival than low or very low risk. CONCLUSIONS: Our experience confirms that GIST are uncommon and aggressive cancers which prognosis is strictly related to tumor size and number of mitosis. Although significant advances on new chemotherapic regimes have been made, to date, radical surgical removal is the only chance of long term survival.