Long-term succinylcholine infusion during isoflurane anesthesia

The characteristics of the neuromuscular blockade produced by prolonged succinylcholine infusion were compared in 40 patients anesthetized with either nitrous-oxide-isoflurane (0.75-1.50% inspired) or nitrous-oxide-fentanyl. Neuromuscular transmission was monitored using train-of-four stimulation and the infusion rate was adjusted to keep the first twitch at 10-15% of its control value. Initially, all patients exhibited a depolarizing-type block, and the infusion rates were similar in the isoflurane (61 micrograms . kg-1 . min-1) and fentanyl (57 micrograms . kg-1 . min-1) groups. Tachyphylaxis developed in both groups and correlated well with the onset of non-depolarizing (phase II) block. Both occurred sooner and at a lower cumulative dose in the isoflurane groups. After 90 min, infusion rates were similar in both groups (isoflurane: 107 micrograms . kg-1 . min-1, fentanyl;: 93 micrograms. kg-1 . min-1). After the infusion was stopped, the recovery of the train-of-four ratio was inversely related to the dose and duration of exposure to succinylcholine, and was slower with nitrous-oxide-isoflurane anesthesia. After 10 min of recovery, patients receiving isoflurane exhibited train-of-four ratios of 0.5 or less after 8.5 mg/kg succinylcholine and 103 min. Corresponding figures for fentanyl patients were 13 mg/kg and 171 min. The block in all 13 patients (eight with isoflurane, five with fentanyl) who did not recover spontaneously was antagonized successfully with atropine and neostigmine. It was concluded that with succinylcholine infusion of 90 min or less, isoflurane accelerates the onset of tachyphylaxis and phase II neuromuscular block without affecting succinylcholine requirements. These results, with isoflurane, were similar to those reported previously with enflurane or halothane.     

Health effects of chronic exposure to tobacco smoke on a non-smoker population]

A study devised to evaluate the effects of chronic exposure to tobacco smoke on the health of a population of non-smokers was conducted in a prison. Fourteen volunteers among male, non-smoking prisoners in good health and without history of lung disease were put for thirty days in a cell that was already occupied by three smokers. These subjects were examined on arrival and on the 30th day of their imprisonment. The examination included filling a questionnaire concerning daily habits and food, respiratory function tests, measurement of CO in the expired air, measurement of nicotine, cotinine, thiocyanates and cadmium concentrations in blood and in urine, and measurement of mutagenic substances excreted. The purpose of the study was to detect possible changes in the variables tested between the first and last days of confinement. No significant difference could be demonstrated within this lapse of time. These results are in agreement with the data available in the literature. In the present state of our knowledge, it is difficult to find evidence of a biological impact, notably on the concentrations of the specific indicators nicotine and cotinine, in subjects passively exposed to tobacco smoke.     

In vivo imaging of rat lymphocytes with an indium 111-labelled anti-T cell monoclonal antibody: a comparison with indium 111-labelled lymphocytes

An indium 111-labelled mouse anti-rat T cell monoclonal antibody, MRC OX-19, was injected intravenously into rats to establish the usefulness of radiolabelled anti-lymphocyte antibodies in imaging lymphoid tissues. Antibody binding in vivo, measured by immunofluorescence analysis of cell suspensions made from lymphoid tissues, was detectable on lymphocytes in blood, spleen and lymph nodes. The extent of binding was time and antibody-dose dependent. Doses of antibody above 80 micrograms/kg body weight resulted in modulation, i.e. loss of CD 5 (T1) molecules from the cell surface, although the cells remained in the circulation. Modulation was demonstrable within 2 h and for at least 24 h after a single injection of antibody. Intravenous injection of 111In-MRC OX-19 resulted in levels of in vivo binding comparable with those seen with unlabelled antibody. Scintillation imaging showed early splenic localisation persisting over 48 h, a more gradual localisation in the lymph nodes seen clearly at 24 h and a steady background. Comparison of the in vivo distribution of labelled antibody and 111In-tropolone-labelled lymphocytes showed that both could be used for external imaging of lymphocytes by scintillation camera.     

Default patterns of patients attending clinics for sexually transmitted diseases.

The influence of gender, propaganda, and treatment methods was studied in relation to default behaviour of patients with sexually transmitted diseases. The overall default rate of men and women was similar, but a larger proportion of men defaulted after the initial visit, while the biggest fall-out in women was after the second attendance at the clinic. The institution of a propaganda campaign was followed by a reduction in defaulting. The statistical significance of this is open to question, however: moreover the observed improvement in default rate was not maintained once the propaganda had been relaxed. Men treated for non-gonococcal urethritis by a regimen which included one injection a week for three weeks showed a highly significantly lower default rate compared with those who received tablets alone.