Relationship of the final α-keratin compositions in dyskeratoses to those along the normal keratinization pathway: aetiological and diagnostic significance

The final alpha-keratin compositions attained in the outer horny layer of 16 dyskeratoses have been compared with the series of compositions which is produced during normal epidermal differentiation. In each case, the abnormal outer horny layer composition corresponded with that of normal basal, spinous, granular or inner horny cells, with, in some cases, the addition of alpha-keratins characteristic of hyperproliferating/regenerating keratinocytes. The results have implications for the aetiology of these diseases. In addition, the distinction between the alpha-keratin patterns in certain of the conditions was sufficiently clear to allow the use of the technique as a non-invasive aid to diagnosis.     

The discrimination between nickel-sensitive and non-nickel-sensitive subjects by an in vitro lymphocyte transformation test

A lymphocyte transformation test (LTT) was able to distinguish between nickel-sensitive subjects and non-nickel-sensitive controls. Sixty-one out of 66 (92%) nickel-sensitive subjects had positive stimulation indices in 6- and/or 7-day assays using 5 micrograms/ml of nickel sulphate, whereas none of the 43 controls gave positive results. Stimulation indices were not enhanced by the patch testing of subjects to nickel before performing the LTT. A weak correlation was seen between the results of the LTT and the macroscopic degree of patch-test reactivity. The concentration of nickel sulphate used (5 micrograms/ml) did not have a significant non-specific mitogenic effect.     

The pharmacodynamics of alcuronium in the elderly

Alcuronium (0.2 mg/kg) was given to 12 elderly patients, mean age 77 years (range 70-88 years) and 12 young patients, mean age 24 years (range 18-32 years) undergoing general anaesthesia. A compound muscle action potential was monitored continuously throughout anaesthesia, using an electromyograph and the train-of-four twitch technique. The rate of onset and maximum block achieved were similar in both the young and elderly patients, as were the times to 20% recovery of the first twitch compared with control (T1 : T0) and fourth twitch compared with the first, (T4 : T1). In contrast, the time to 70% recovery of T1 : T0 was significantly prolonged in the elderly (138 as compared with 89 minutes: p less than 0.01) as was the recovery index (25-75%) for T1 : T0 (95 as compared with 46 minutes: p less than 0.01) and the time to 70% recovery of T4 : T1 (181 as compared with 131 minutes: p less than 0.05). The recovery curves for T1 : T0 and T4 : T1 were also significantly different in the elderly from the young group (p less than 0.01 in both instances). These results show that the duration of action of alcuronium is significantly prolonged in the elderly.     

TRANSPLACENTAL DISTRIBUTION OF ATRACURIUM, LAUDANOSINE AND MONOQUATERNARY ALCOHOL DURING ELECTIVE CAESAREAN SECTION

Maternal venous (MV), umbilical venous (UV) and umbilical arterial(UA) blood samples were obtained for assay of atracurium, laudanosineand monoquaternary alcohol concentrations in 22 healthy patientsundergoing elective Caesarean section under general anaesthesia.At delivery (at a mean time of 8.2 min after atracurium 0.3mg kg^–1), the mean UV concentrations were 103 ng ml^–1(range 44–189 ng ml^–1) for atracurium, 26 ng ml^–1(range 6–60 ng ml^–1) for laudanosine and 59 ng ml^–1(range 21–148 ng ml^–1) for monoquaternary alcohol.The ratios of UV: MV, UA:MV and UA:UV blood concentrations wererelated positively to time since injection of atracurium forall three substances (P < 0.01 in each instance). The UV:MVratio at delivery was greatest for laudanosine: mean 19.4% (range1-35%), compared with 7% (range 2-21%) for atracurium and 10%(range 0-15%) for monoquaternary alcohol. These low values confirmthat, although atracurium crosses the placental barrier andits metabolites may be found in the fetus, the drug is safeto use during Caesarean section.