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Notes: Six children and six adults were given a single dose of a sustained release theophylline preparation (Nuelin Retard®) after an overnight fast and later after a standardized breakfast. Food significantly reduced the absorption rate of theophylline whereas the extent of absorption of theophylline was unaffected by food. Under steady state treatment the fluctuations in the serum levels of theophylline were small when the tablets were taken after meals twice a day showing that this dose regimen was sufficient. No characteristic absorption or elimination phases were seen during the steady state dose interval, and the time to peak serum theophylline level showed great variation. Serum theophylline control about 4 h after fasting intake of the tablet is recommended.

Notes: Over a 3-month period 22 asthmatic children were treated with a sustained-release theophylline preparation (Nuelin Retard®, Riker) in twice-daily doses. During the first 2 weeks of treatment slight side-effects were observed in 14 children. Over the remaining 10-week period only four children experienced minor side-effects.Serum theophylline levels 4 hours after tablet administration were measured three times and serum levels just before tablet administration were measured once during the observation period. The average difference between the serum levels of theophylline just before tablet administration and the corresponding serum value 4 hours afterwards was 4.2 μg/ml. The serum values 4 hours after tablet administration showed an insignificant fall throughout the period and patient compliance was assessed as good.When the average requirements of theophylline in mg/kg found by Wyatt et al. (15) (Table 2) were used as initial doses, few dosage adjustments were necessary and no serum values were greater than 26.2 μg/ml, but in order to avoid serum levels above 20 μg/ml initial doses should be decreased about 10% and final adjustment made with the aid of serum theophylline measurement under steady state conditions.In children, Nuelin Retard given in two daily doses is capable of maintaining a constant therapeutic serum concentration for the whole 24-hour period.

Notes: Abstract An example of diffusion in a natural solid rock is described using 87Sr as a tracer. The distribution of excess radiogenic 87Sr across the contact of a metamorphosed basic dyke in a granodioritic gneiss is shown to fit closely to a mathematically modelled theoretical diffusion curve. It is suggested that the excess radiogenic Sr was generated by the breakdown of older Rb-rich biotite in the country rock to form chlorite during a late-stage greenschist facies metamorphism, and then taken up into a fluid phase migrating along the country rock — dyke interface. This fluid introduced silica, alkalies, light REE, H2O, CO2, N and Cl into the marginal zone of the dyke, probably during fluid migration along grain boundaries. The present irregular distribution of the volatile constituents across the contact and in the dyke excludes a diffusion controlled distribution. The distribution of volatiles probably reflects the influence of the existing mineralogy on the geochemical anomaly actually recorded from a post magmatic process. Evidence is presented that the diffusivity of radiogenic Sr was enhanced by the presence of a volatile phase.

Notes: Summary 1. Computer generated, artificial songs (Fig. 1) were played to grasshoppers of the gomphocerine speciesOmocestus viridulus L. in a temperature-regulated, echo-reduced chamber (Fig. 2). The animals often responded by singing their response song, and the occurrence of response songs was used to indicate the animals' preference for the artificial songs. At various temperatures, the chirp duration and impulse rate preferred by the animals were determined and compared with the magnitudes of these parameters in the response songs. 2. The duration of the response songs decreases with temperature (Fig. 5), and so does the chirp duration (Fig. 3). The chirp rate (which in this species is the reciprocal of the chirp duration) decreases during a response song (Fig. 6). 3. In the first experiments the chirp duration was varied in the artificial songs, while the ratio chirp rate to impulse rate was kept constant (as in the natural songs). The preferred chirp duration changes more with temperature than does the chirp duration of the response songs (Fig. 3). At all temperatures, songs with chirp durations half or double of the preferred one could also release a response song. The animals even responded to chirp durations outside the natural range (Fig. 3). 4. In the second experiments, the chirp rate (C) and impulse rate (I) at 28 °C (C28 and I28) and 38 °C were combined into four different songs: C28I28, C38I38, C28I38 and C38I28. The former two songs correspond to the natural songs at 28 ° and 38 °C, whereas the latter ones are artificial. The temperature of the listening animals was also varied. The choices made by femal grasshoppers showed that the chirp rate is the major parameter and the impulse rate the minor parameter in determining the acceptance of a song. 5. Four different criteria for measuring the female song discrimination were compared: (a) the behavioural threshold (i.e. the sound level of an artificial song which is just sufficient for response songs to be released in the females), (b) response or no response, (c) the number of response songs in a response, and (d) whether the response was given to the 1st, 2nd or 3rd song presentation. (a) was more sensitive than (b), and both gave rather similar results. In (c) and (d) the responses appeared to be independent of the type of songs presented. 6. The behavioural threshold increased before and decreased after egg deposition (Fig. 7).