Algal extracellular organic matter pre-treatment enhances microalgal biofilm adhesion onto microporous substrate.

Adhesive biocoating has microstructure composed of biomolecules to entrap viable cells in a stabilized matrix over exposed surfaces. Although marine benthic diatoms are a common group of algae excreting substantial amount of extracellular polymeric substances (EPS), studies regarding the utilization of these EPS are scarce. Using the soluble EPS derived from Navicula incerta and pre-deposition of it as a thin conditioning layer on microporous polyvinylidene fluoride (PVDF) membranes, the pre-coated surface was used to investigate the cell binding affinity of three marine microalgae, namely Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta. Microalgae actively engaged themselves on the pre-coated membranes which was 10 times greater than the initial cell adhesion degree. Soluble EPS is mainly comprised of polysaccharide while bounded EPS is mainly comprised of protein. On EPS pre-coated membranes, N. incerta released the least amount of bounded polysaccharides (<100 mg m-2) and vice versa for the other two because EPS production is usually maximized to assist cell adhesion onto unfavorable substrates. In stark contrast, when the adaptation period (first 6 h) ended, cells began to secrete more bounded protein for cell growth, and an increasing trend of protein content found in N. incerta has verified its optimal adaptation onto the biocoating itself. On pristine PVDF membranes, the adhesion degree was ranked in ascending order: C. fusiformis, N. incerta and A. coffeaeformis. Interestingly, after the pre-coating process, the order was reported as: A. coffeaeformis, N. incerta and C. fusiformis, but it should be noted that C. fusiformis demonstrated fluctuating cell colonization degree and bounded EPS production over time. In other words, the biofilm's susceptibility was confirmed since the cells latched loosely on the membranes rather than in a biofilm matrix. Biocoating enables uniform cell distribution and firmer biofilm growth, opening the door to vast future applications in environmental bioremediation and sensing.

Gastric emptying in the postpartum period.

We measured gastric emptying, using the technique of paracetamol absorption, in eight women on their first and third postpartum day. Gastric emptying was rapid and there was no difference between the first and third day in the time to peak plasma concentration of paracetamol. Six women returned after six weeks for a further study. Gastric emptying was still rapid but the metabolism of paracetamol appeared to be slower than that found during the immediate postpartum period. These findings suggest that fluid fasting guidelines in patients more than one day postpartum need not be different from those in non-pregnant patients.

Cross-sectional study of complications of inhalational anaesthesia in 16,995 patients.

Patients undergoing anaesthesia in which halothane, enflurane or isoflurane were used, were surveyed with reference to 16 unwanted effects selected by the nominal group method. A simple record card was completed at the time of anaesthetic administration. The overall incidence of complications was 13.9%. One complication was reported in 10.8% of the cases, and more than one in 3.1%. Complications were more frequent in the obese, the elderly and those patients receiving isoflurane, but in view of the small overall use of this agent, the anaesthetists involved may still have been on a learning curve.

Intra-arterial blood sampling for clotting studies. Effects of heparin contamination.

Prothrombin time and activated partial thromboplastin time were measured in two groups of 30 patients each. Blood sampled from an arterial line after various discard volumes and from a central venous line were compared with direct venipuncture control samples. The arterial line flushing solution contained 1 unit of heparin per ml in group 1 and 2 units per ml in group 2. Our results confirmed that clotting studies carried out on blood samples from an arterial line or central venous line correlate well with those obtained from a venipuncture sample. The only exception was activated partial thromboplastin time in group 2 patients when the discard volume from the arterial line is only 2.5 ml above the deadspace volume of the connecting line. At least 5 ml of discard volume must be withdrawn before sampling, to obtain reliable results.

Postoperative absorption of controlled-release morphine sulphate. A study in patients given no parenteral opioids.

The absorption of morphine sulphate in a controlled-release formulation was studied in 12 patients who had undergone unilateral inguinal hernia repair under a light general anaesthetic and ilio-inguinal block. Serum morphine concentrations were measured serially and gastric emptying was assessed by measurement of paracetamol absorption. Three patients had delayed gastric emptying and impaired morphine absorption in the immediate postoperative period. Four hours later, there was a significant reduction in gastric emptying in eight patients who had normal paracetamol and morphine absorption in the immediate postoperative period.

A comparison of propofol and methohexitone as anaesthetic agents for electroconvulsive therapy.

This study was designed to compare the effects of propofol and methohexitone upon the haemodynamic changes during, and the recovery from, anaesthesia for electroconvulsive therapy. Thirty patients were included, each patient being studied on two successive treatments with both propofol 1-1.5 mg kg-1 body weight, and methohexitone 0.75-1 mg kg-1 body weight. The duration and intensity of the modified convulsion were similar for both agents. There was no significant difference with respect of time to eye-opening, time to walking and observer assessment of recovery at 5 and 10 min for the two drugs. The direction of haemodynamic changes during the treatment were similar with both agents, although a significantly greater decrease (P less than 0.05) in diastolic arterial pressure following induction with propofol compared to methohexitone, and a significantly greater increase (P less than 0.05) in systolic arterial pressure following the fit with methohexitone compared to propofol, were noted.

Plasma catecholamine concentrations--changes after infiltration with local anaesthetic solutions and adrenaline during bat-ear surgery.

Plasma catecholamine concentrations were measured in 12 patients who had bilateral bat-ear surgery following infiltration of each ear with 2 ml 2% lignocaine with adrenaline 1:100,000. Venous blood samples were withdrawn before and at set intervals after infiltration. Plasma adrenaline concentration increased from 0.8 pmol/ml to a peak of 2.2 pmol/ml at 2 minutes after infiltration; this is an increase of 175%. There was no significant change in plasma noradrenaline concentration.

Dangers of anaesthesia in Munchausen's syndrome.

Patients with Munchausen's syndrome often undergo multiple surgical operations under general anaesthesia. They tend to have multiple exposures to routinely used anaesthetic agents. A patient with Munchausen's syndrome who developed an anaphylactoid reaction to thiopentone is described and the importance of obtaining previous case notes is stressed.

Oxygenation during electroconvulsive therapy. A comparison of two anaesthetic techniques.

Oxyhaemoglobin saturation was monitored continuously during electroconvulsive therapy in two groups of patients. All patients were anaesthetised using methohexitone (40-100 mg) and suxamethonium (25-50 mg). In group 1 (n = 48), the patients' lungs were ventilated manually with oxygen in air (40-50%) during the modified convulsion. In group 2 (n = 47), the convulsion was allowed to subside before recommencing manual ventilation with a similar gas mixture. Eight patients in group 1 and seven patients in group 2 received more than one shock and were excluded, leaving 40 patients in each group. In group 1, one patient had a minimum oxygen saturation of less than 90% after the electric shock as opposed to 11 in group 2 (p less than 0.01). Five of the patients in group 2 had a saturation of less than 80%. It is concluded that patients undergoing electroconvulsive therapy should be ventilated with an oxygen-enriched gas mixture during the convulsion induced by the electric shock in order to avoid hypoxaemia.