665 the patient is interrupted, the current and pump are cut off by a thermistor when the fluid temperature reaches 42 °C, and an alarm is activated. However, if air is drawn into the disposable tubing the heater tube can reach 300°C or even red heat in the few seconds before the thermistor is activated. This happened in our unit when one of the air filters was incorrectly seated and air was sucked into the system, halting the flow of dialysate through the heater tube and allowing it to heat up rapidly. A technician attending to the fault sustained a partialthickness burn on the hand by inadvertently touching the tube. Air might also enter the heater tube if a clamp is inadvertently left on the lines or if joints are insecure. Overheated dialysate cannot reach the patient. LKB Instruments Ltd are looking at ways of avoiding repetition of this incident. We understand that although more than sixty of these machines are in use in the U.K. this problem has not been reported before. Renal Unit, Dundee Royal Dundee

Infirmary,

BRIAN TOMLINSON

3

- 1.-22

15

10

5

20

DAYS AFTER LEVAMISOLE

Fig. 2-Increase of levamisole (±S.E.).

value of activated T cells after

mean

Department of Medicine, Ninewells Hospital

W. K. STEWART

Department of Medical Physics, Ninewells Hospital

of early E rosettes is a result of stimulated T lymphocytes or a maturation effect on other lymphocyte subpopulations such as null cells.6 Levamisole could, however, promote a better expressivity of T-cell receptors, as suggested by Wybran and

A.R. RIMMER

Govaerts.7

LEVAMISOLE INCREASES ACTIVATED T LYMPHOCYTES

SiR,-Activated T lymphocytes were determined in the peripheral blood of ten healthy individuals by the early, E-rosetteformation assay of Felsburg et al.’ 150 mg levamisole was taken in one dose orally , and early E rosettes were assayed 2 and 1 days before levamisole intake and 3, 5, 10, 15, and 20 days afterwards. The individual values (fig. 1) show a signifi-

Department of Rheumatology, University of Basle,

M. ROSENTHAL

CH-4055 Basle, Switzerland

HOW MUCH INTRAVENOUS FLUID DOES THE PATIENT GET?

SIR,-The ’Polyfusor’ is a semi-rigid, collapsible, polyethylene container designed for use with or without an airway. The container holds 50 ml more than the volume nominally specified to allow for the amount of infusate left behind at the completion of the infusion from a polyfusor without an airway (unvented); one litre polyfusors contain 1050 ml, half litres 550 ml. The container can be vented by insertion of an airway into the top of the inverted polyfusor, but this adds the

50-) % act-cells

RESIDUAL VOLUMES OF

100 ONE-LITRE

PERFUSORS

DAYS

Fig. 1-Individual values of activated T cells in peripheral blood before and after levamisole. increase of circulating activated T cells in all volunteers. In five the increase was seen as early as 3 days after levamisole. The early E rosettes (fig. 2) reached a peak on day 5, remained high for a further 10 days, and then fell back to baseline values by day 20. The effect of levamisole on early E rosettes supports previous reports of its possible modulatory effect on cell-mediated immunity.2-3 I do not know whether the increased percentage cant

1 2

3

Felsburg, P. J., Edelman, R., Gilman, R. H. J. Immun, 1976, 116, 1110. Symoens, J., Rosenthal, M. J. reticuloendothel. Soc. 1977, 21, 175. van Ginckel, R. F., Hoebeke, J. Eur. J. Immun. 1976, 6, 305.

4

Renoux, G., Renoux, M., Teller, M. N., McMahon, S., Guillaumin, J. M. Clin exp

Immun. 1976, 25, 288.

5 van Wauwe, J., van Nijen, G. ibid. (in the press).

i

i

i

hazards of air embolism and contamination by bacteria or microparticles of polyethylene. Ideally, therefore, the container should deliver the nominated volume of sterile, uncontaminated infusion fluid when used unvented. To find out whether polyfusors conform to this idea, containers were suspended approximately 1 .2 m above the infusion site and connected via Baxter FRC2055 intravenous giving sets to 1-30 mm intravenous cannulse. 100 one litre and 50 half litre polyfusors were allowed to infuse their contents to completion and the residual volume was measured by aspiration with a syringe. 6. Rosenthal, M., Trabert, U., Müller, W. ibid. 1976, 7. Wybran, H., Govaerts, A. ibid. 1977, 27, 319.

25, 493.

Levamisole increases activated T lymphocytes.

665 the patient is interrupted, the current and pump are cut off by a thermistor when the fluid temperature reaches 42 °C, and an alarm is activat...
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