Characterising the structure of photosynthetic biofilms using fluid dynamic gauging.

A new configuration of the fluid dynamic gauging technique for measuring soft layers on surfaces was used to monitor the growth of a cyanobacterium, Synechococcus sp. WH 5701, on stainless steel (SS), glass and an indium tin oxide (ITO) on a polyethylene terephthalate (PET) substratum. The biofilm thickness increased steadily over 4 weeks and exhibited noticeable changes in microstructure and strength. The biofilms all exhibited a two-layer structure, with a compact layer next to the substratum and a loose layer above. Biofilms on ITO or SS exhibited cohesive failure when removed by fluid shear whereas those on glass exhibited adhesive failure. The technique is able to elucidate various aspects of biofilm behaviour, as illustrated by the action of a biocide (NaOCl) on a mature biofilm.

IgG subclass response to gamma globulin administration in burned children.

Sixteen children admitted to the North East Thames Regional Burn Unit, Billericay, were given immunoglobulin in the form of Sandoglobulin (0.3 g/kg body wt) between 36 h and 72 h after burn injury. In addition, children who developed a prodromal illness, similar to the toxic shock syndrome (TSS), prior to the administration of Sandoglobulin, were also given fresh frozen plasma and packed red blood cells where indicated. Mean serum levels of IgG1, IgG2 and IgG3 were obtained on a daily basis for the first 7 days postburn. All children survived the injury and a noticeable improvement in the clinical condition of the ill children was noted after immunoglobulin administration. A rise in serum levels of the subclasses investigated also correlated with the immunoglobulin administration and was sustained over the study period, which is the time a burned child is maximally at risk of developing TSS on our unit. There may be an 'at risk' group of children in the general population who have naturally low levels of serum IgG2.

Serum cholinesterase levels after thermal injury. Is treatment required?

Changes in serum cholinesterase (also known as pseudo- or non-specific cholinesterase) activity have been measured in 20 patients after thermal injury. In 19 patients a marked fall was noted at around day 5 post-burn, and recovery to normal levels was variable and in some cases prolonged. A variety of symptoms, for example, dyspnoea and confusion, have been attributed to lowered serum cholinesterase activity and some workers have gone so far as to advocate blood transfusion to treat such a condition (Price et., 1970; Frohlich, 1977). In this study we found 13 patients (65 per cent) with such symptoms coexisting with a low serum cholinesterase activity. However, we do not believe these symptoms were directly attributable to the low enzyme activity for the following reasons: In only three of the 13 patients were symptoms observed at times when the lowest cholinesterase activity was recorded. A conventional explanation for these symptoms was available, except in three cases with abdominal distension. In six cases no symptoms were observed despite very low cholinesterase levels.

Stratification of prognosis in granulocytopenic patients with hematologic malignancies using the APACHE-II severity of illness score.

The APACHE-II (acute physiology and chronic health evaluation) severity of disease classification system was used to stratify prognosis of granulocytopenic patients with hematologic malignancies. A total of 146 admissions were retrospectively reviewed. In 26 ICU admissions, mortality was 69.2%; in 120 admissions to the ward, mortality was 15.8%. The APACHE-II score successfully stratified prognosis in both ward and ICU settings. Respiratory failure and the presence of pneumonia on chest x-ray were identified as poor prognostic factors. ICU patients admitted for monitoring or postoperative care had a better prognosis than those admitted for severe cardiopulmonary compromise. We suggest that the APACHE-II system is useful for stratifying prognosis for clinical research in this group of patients, although it remains to be shown whether it will be useful in predicting the prognosis of individual patients.

Changes in plasma urate concentration immediately after acute myocardial infarction.

The plasma urate concentration of 70 patients with acute myocardial infarction increased progressively up to the seventh day and was significantly higher than in a group of 23 patients with ischaemic changes only. Diuretic treatment might have accounted for an early rise in urate levels but the persistent increase seen at seven days could not be so explained.