Field evaluation of a model of photothermal flowering responses in a world lentil collection.

A model to predict flowering time in diverse lentil genotypes grown under widely different photothermal conditions was developed in controlled environments. The present study evaluated that model with a world germ plasm collection of 369 accessions using two field environments in Syria and two in Pakistan. Photoperiod alone accounted for 69% of the variance in 1/f, the reciprocal of time (d) from sowing to flower. In contrast, temperature alone did not account for a significant proportion of variation in flowering time due to the exposure of plants to supra-optimal temperatures in the late-sown Syrian trial. With the model mean pre-flowering values of photoperiod and temperature combined additively to account for 90.3% of the variance of 1/f over accessions. The correlation of field-derived estimates of temperature sensitivity of accessions to glass-house-derived estimates was significant at P = 0.05, but the equivalent correlation for estimates of photoperiodic sensitivity was higher at P < 0.01. Flowering in the field was better measured as time from sowing to 50% plants in flower rather than time to first bloom or its node number. Dissemination of the lentil crop following domestication in West Asia to the lower latitudes such as Ethiopia and India has depended on selection for intrinsic earliness and reduced sensitivity to photoperiod. Movement from West Asia to the higher latitudes accompanied by spring sowing has resulted in a modest reduction in photoperiod sensitivity and an increase in temperature sensitivity.

Propofol inhibits enzymatic degradation of alfentanil and sufentanil by isolated liver microsomes in vitro.

We have studied the effect of propofol on the enzymatic degradation of alfentanil and sufentanil utilizing isolated liver microsomes obtained from pig and human liver. Propofol inhibited dose-dependently the oxidative metabolic degradation of alfentanil and sufentanil by both microsomal preparations. The calculated concentration of propofol causing 50% inhibition of metabolic degradation (IC50) was 32.6 mumol litre-1 for alfentanil and 22.1 mumol litre-1 for sufentanil in pig liver microsomes. Similar values of inhibitory activity of propofol (IC50 values 62.8 and 52.9 mumol litre-1, respectively) were observed using human microsomes prepared from liver taken from an organ transplant donor. We suggest that propofol in clinically relevant concentrations interferes with oxidative metabolic degradation of alfentanil and sufentanil in the microsomal fraction of pig and human liver.

The route of prolonged morphine administration affects the pattern of its metabolites in the urine of chronically treated patients.

Differences in the patterns of urinary morphine metabolites were determined in 15 patients after the prolonged administration of morphine via various routes (oral, subcutaneous, intravenous). The possible correlation between metabolite pattern and the route of prolonged morphine administration was investigated. It was established that the concentration ratios of the active metabolite, morphine-6-glucuronide to morphine and its inactive metabolite, morphine-3-glucuronide are significantly (p less than 0.05) higher after prolonged oral morphine treatment than after the systemic administration (subcutaneous or intravenous infusion) of morphine. It may therefore be concluded that patients receiving morphine orally produced significantly greater amounts of its pharmacologically more active metabolite than patients subjected to chronic systemic morphine treatment.

Allozyme and morphological variability, outcrossing rate and core collection formation in lentil germplasm.

A survey of qualitative genetic variation at 3 morphological trait loci, 17 isozyme loci and a putative isozyme locus (amylase) was made for 105 lentil (Lens culinaris Medikus) germplasm accessions from Chile, Greece and Turkey. New alleles were found for Lap-1, Me-2, Pgm-c, Pgm-p and 6-Pgd-c. The average proportion of polymorphic loci per population was 0.19, with a range of 0 to 0.42 over populations. Germplasm from Chile was equally variable to that from Greece and Turkey on the basis of individual loci and in a multilocus sense, despite its post-Columbus introduction to the New World. Evidence was found from associations between allelic states at different loci of a complex multilocus structure of lentil populations. A single multilocus genotype represented 10.2% of all plants sampled. The rate of outcrossing varied from 2.2% and 2.9% in Turkish and Greek landraces to 6.6% among Chilean populations. Using the survey data, a random sampling strategy for core collection formation was compared with two stratified sampling methods. The advantage of stratified sampling over random sampling was only significant at P=0.28.

Characterization of responses to temperature and photoperiod for time to flowering in a world lentil collection.

The times from sowing to first flowering (f) of 231 accessions of lentil (Lens culinaris Medik.), comprising germ plasm from eight countries and breeding lines from ICARDA in Syria, were recorded in four glasshouse environments; two photoperiods (16 and 13 h/day) combined with warmer (24°/13°C) and cooler (18°/9°C) day/night temperatures. The linear model 1/f=a+bT + cP (where T is mean diurnal temperature and P is photoperiod) provided an average fit over the 231 accessions of r (2)=0.852. Since there is no interaction term in this linear model, the flowering responses of an accession to temperature and photoperiod are independent. The values of the constants b and c indicate relative responsiveness of rate of progress towards flowering (1/f) to temperature and photoperiod, respectively. Comparison among the 231 accessions showed a weak, but significant, negative correlation between the values of b and c (r=-0.291, P<0.01). Since the proportion of the variance of b not attributed to its linear regression on c was >0.91, we conclude that these phenological responses are under separate control and that there is considerable scope for selection of any combination of sensitivities to temperature and photoperiod in lentil. Just as a large proportion of the variation among accessions in mean time to first flowering was attributed to country of origin, so also was variability in the values of the constants a, b, and c. In particular, sensitivity to photoperiod (i.e., the value of constant c) was dependent upon latitude of origin. Breeding lines from ICARDA were equally variable in a, b, and c as were germ plasm accessions from elsewhere, while the mean values were similar to those of accessions from neighboring Jordan. A single accession of wild lentil (L. culinaris subsp. orientalis) from Turkey showed flowering responses to T and P similar to the mean value of accessions of cultivated lentil from that country. Results from diverse environments for the Argentinian cv Precoz show that the use of this linear model facilitates predictions of time to flowering in any environment (within wide limits) of known mean temperature and photoperiod. The model, then, minimizes the need for multisite evaluations of phenology, since predictions of pre-flowering duration in any environment, and characterization of flowering responses to photoperiod and temperature, can now be achieved by screening germ plasm in a few, carefully selected locations.

Assessment and management of chronic pain.

The approach to the management of patients with a variety of chronic pain problems who present to the multidisciplinary Grey's Hospital Pain Clinic is outlined.

Self-administered intravenous analgesia during labour. A comparison between pentazocine and pethidine.

Pentazocine or pethidine was administered to healthy parturients up to the time of delivery using a self-demand (self-administration on demand) intravenous apparatus, the Cardiff Palliator. Good analgesia was obtained with both drugs. The patients receiving pethidine exhibited side-effects (nausea, vomiting and drowsiness), whereas there were no side-effects among those receiving pentazocine. Apgar and neurobehavioural scores of the babies of mothers in both groups were the same and did not differ from those of a third group of babies, the mothers of whom had received 4-hourly intramuscular pethidine on demand according to the usual hospital routine. The self-administration technique proved a safe and effective means of providing analgesia during labour and delivery, with pentazocine having a decided advantage over pethidine because of its lack of side-effects.

Aspartate aminotransferase allozyme variation in a germplasm collection of the domesticated lentil (Lens culinaris).

Variation at a polymorphic Aspartate aminotransferase locus was assayed in a sample of 298 accessions from the ICARDA germplasm collection of the domesticated lentil (Lens culinaris). Two alleles Aat-1 (F) and Aat-1 (S) were detected with global frequencies of 0.51 and 0.49, respectively. Fifty-nine percent of accessions were polymorphic for both alleles. The frequency of outcrossing was estimated from the observed heterozygosity to be about 1%. This is higher than direct estimates of outcrossing and implicates selection in favour of heterozygous gene combinations. Significant variation in allele frequency and in the occurrence of polymorphic accessions was observed between countries or geographic areas. Significant associations were observed between the allozymes and agronomic characters. In particular high frequency of Aat-1 (F) appeared to be associated with late flowering and maturity and low yield.

Chronic pain problems. Experience in a pain clinic.

Our experiences during a year of activity in a pain clinic are presented. Most of the patients treated had pain due to malignant disease. The assessment and management of these patients are described together with the treatment given and the result.