Efficacy of oral ketamine for providing sedation and analgesia to children requiring laceration repair.

A prospective, double-blind, placebo-controlled, randomized clinical trial was conducted to study the efficacy of oral ketamine for providing sedation and analgesia to children during laceration repair. Thirty children between the ages of one and seven years with lacerations that required suturing were randomly assigned to receive either oral ketamine (10 mg/kg) or an identically flavored placebo syrup prior to suturing. Patients were assessed by means of a tolerance score reflecting behavioral correlates of perceived pain at the time of both lidocaine injection and suturing. In addition, a sedation score for monitoring patient level of consciousness was used. The ketamine-treated group demonstrated a significantly greater tolerance to both lidocaine injection (P < 0.001) and suturing (P = 0.009) in comparison to the placebo-treated group. The ketamine-treated group also achieved a significantly greater degree of sedation (P = 0.012). No significant respiratory or circulatory adverse effects were seen in either group, although 26% of patients who received ketamine experienced minor, transient adverse effects. We conclude that oral ketamine in a dose of 10 mg/kg provides effective sedation and analgesia to young children undergoing wound repair.

The influence of dinitrophenol on phloem transport along the stolon of Saxifraga sarmentosa.

Dinitrophenol in concentrations of 5×10(-3) M applied to the centre 30 cm of 60-70 cm stolons of Saxifraga produces a strong and reversible inhibition of the phloem transport of (137)Cs or (14)C-assimilates. There is every reason to believe that this effect is localised in the sieve tubes; callose formation does not occur. This evidence is very difficult to reconcile with the Münch hypothesis; it seems on the contrary to demand a theory of active pumping.

The simultaneous movement of two ions in the phloem of the Saxifraga stolon.

Paris of tracers were applied simultaneously to the long thin stolons of Saxifraga sarmentosa. After several hours of translocation the very precise pattern of exponential fall-off was examined and interpreted in the light of a model of mass flow with leakage. (42)K appears to leak faster than (22)Na; (86)Rb is very close to (42)K. The anion (82)Br shows a lower fall-off than (137)Cs; this is tentatively regarded as due to a much-reduced leakage, though it might imply a higher velocity. The implications of these findings for sieve-tube mechanism are uncertain.

The effect of nitrogen on the movement of tracers down the stolon of Saxifraga sarmentosa, with some observations on the influence of light.

The movement of applied (137)Cs and of naturally-assimilated (14)C down the long stolon of Saxifraga is strongly inhibited by confining a length of 10 to 30 cm of the stolon in an atmosphere of nitrogen. The inhibition is reversible, normal transport being restored after less then 4 h when the stolon is returned to air from 5 h in nitrogen. Callose formation does not seem to be involved. There is evidence that local darkness has a similar adverse effect on phloem transport.These findings are considered antagonistic to the pressure-flow hypothesis, but favourable to the active mass-flow theories.

Movement of [(14)C]sucrose along the stolon of Saxifraga sarmentosa.

The characteristics of (137)Cs transport along the stolon of Saxifraga previously reported have been confirmed for applied sucrose and natural assimilate. Long-distance transport is strictly unidirectional, with a symmetrical short-distance spread from the point of application. Only the latter takes place in a long piece of excised stolon. Transport is readily reversed when the parent plant is darkened and the daugther, plantlet allowed to photosynthesise. These findings strongly support a mass-flow mechanism for the stolon. They also confirm the value of (137)Cs as a tracer for assimilate movement, though in contrast to assimilate it suffers appreciable lateral leakage. Pulse labelling of the subtending leaf failed to produce a sharp peak of activity in the stolon. A flattening with time of the (14)C profile is considered to be due to differing linear velocities in parallel sieve tubes.

Unidirectional movement of tracers along the stolon of Saxifraga sarmentosa.

When radioactive tracer is applied locally to the stolon of Saxifraga its long-distance movement after 18 hours is found to be strongly polarised; there is in addition a short-distance movement which is unpolarised. With caesium, the long-distance movement is predominantly in the phloem; with strontium in the xylem. These interpretations, a priori probable, were confirmed by artifically reversing, separately, the xylem and the phloem currents. With long pieces of excised stolon only the unpolarised short-distance movement is observed. These results constitute evidence against simultaneous bidirectional translocation in the same sieve tube, and are consistent with either the Münch or the electro-osmotic theory.