Plasmonic sensors for the competitive detection of testosterone.

The ability to detect small molecules in a rapid and sensitive manner is of great importance in the field of clinical chemistry, and the advancement of novel biosensors is key to realising point-of-care analysis for essential targets. Testosterone is an example of such a small molecule, the detection of which is important in both clinical analysis, and in the sporting industry to prevent doping. As such, a portable, rapid and sensitive test for testosterone would be of great use across a variety of analytical fields. Here we report on a novel method of testosterone analysis, based on a competitive inhibition assay utilising functionalized gold nanoparticles. Two sensing platforms are directly compared for the detection of testosterone based on both classical SPR and LSPR. We provide an in-depth discussion on the optimum surface chemistries needed to create a stable detection conjugate before successfully detecting testosterone using our newly developed portable 4-channel SPR instrument. We provide the first detailed study into the comparison of SPR and LSPR for the analysis of a small molecule, and provide a simple and effective method of testosterone detection that could potentially be extended to a variety of different analytes.

Spinal anaesthesia for caesarean section: an ultrasound comparison of two different landmark techniques.

BACKGROUND: Spinal anaesthesia performed at levels higher than the L3-4 intervertebral space may result in spinal cord injury. Our aim was to establish a protocol to reduce the chance of spinal anaesthesia performed at or above L2-3. METHODS: One hundred and ten consenting patients at 32weeks of gestation or greater scheduled for non-emergency caesarean section under spinal anaesthesia were randomly allocated to have needle insertion performed at an intervertebral space determined by one of two landmark techniques. In Group A, if the intercristal line intersected an intervertebral space, this space was selected or if the intercristal line intersected a spinous process the space immediately above was selected. In Group B, if the intercristal line intersected an intervertebral space or a spinous process, the intervertebral space immediately below was chosen. The actual intervertebral space chosen was identified using ultrasound by a blinded investigator. RESULTS: In Group A, an intervertebral space at or above L2-3 was marked in 25 (45.5%) patients compared with 4 (7.3%) in Group B (P <0.001). In 5/55 (9.1%) patients in Group A, the intervertebral space initially chosen was L1-2 whereas this occurred in no patient in Group B. There was no difference between groups in number of needle passes or attempts, onset of block at 5, 10 and 15min or need for rescue analgesia. CONCLUSION: Our data suggest that when performing spinal anaesthesia in pregnant patients, if the intercristal line intersects an intervertebral space then the space below should be chosen and if the intercristal line intersects a spinous process then the interspace below should be chosen. This will reduce the incidence of spinal anaesthesia performed at or above L2-3.

Anaesthesia for phaeochromocytoma and sickle cell disease in pregnancy.

A 33-year-old woman (G(1)P(0)) presented to a maternity hospital at 36 weeks' gestation. She suffered from sickle cell disease with three acute crises in the previous five months of her pregnancy. She also had a phaeochromocytoma with inadequately controlled hypertension. This report describes the multi-disciplinary work-up and peri-operative management necessary to optimise her medical condition before caesarean section at 39 weeks' gestation and subsequent removal of a malignant phaeochromocytoma.

The effects of propofol and thiopentone on forearm circulation.

Some effects of propofol and thiopentone induction on the peripheral circulation of healthy patients are examined using mercury strain gauge venous occlusion plethysmography of the forearm. Results indicate that both drugs produce a statistically significant decrease in mean arterial blood pressure and forearm blood flow. Forearm vascular resistance remains unchanged after either drug. These data suggest that bolus dose induction of anaesthesia with propofol does not cause arterial vasodilatation of the limb and that a cause for the reduction in mean arterial pressure must be sought elsewhere.

A comparison between propofol and thiopentone as induction agents in obstetric anaesthesia.

Two comparable series of 21 patients who had elective Caesarean section had general anaesthesia induced by thiopentone sodium 4.53 (SD 0.65) mg/kg or propofol 2.15 (SD 0.26) mg/kg. Maintenance was similar for both groups. Blood pressure was lower in the propofol group during the induction-delivery interval. Umbilical/maternal vein ratios for thiopentone and propofol were 8.5 and 7.2 respectively. Infant wellbeing as judged by Apgar score and cord blood analysis showed little difference between the two induction agents. Factors associated with uterine relaxation and bleeding were similar in the two groups.

The effects of thiopentone and propofol on upper airway integrity.

One hundred and fifty-eight unpremedicated patients scheduled for elective surgery were allocated randomly to receive an unsupplemented induction dose of thiopentone or propofol. Visualisation of the vocal cords by standard laryngoscopy was possible more often after propofol (p less than 0.01). Pharyngeal and laryngeal reactivity was similarly depressed more frequently.