Maternal and neonatal disposition of pethidine in childbirth--a study using quantitative gas chromatography-mass spectrometry

An assay for pethidine using gas chromatography-mass spectrometry with single ion monitoring has been developed for its analysis in the blood of neonates whose mothers received pethidine during childbirth. Concentrations were determined from the height of the peak at m/e 218 derived from pethidine compared with that at m/e 234 derived from the internal standard lignocaine. Results from 10 mothers and their babies show the time-related passage of pethidine across the placenta. The elimination half-life of the drug from neonatal blood was 22.7h compared with 3h in the adult.     

Immunoelectrophoretic analysis of seed proteins from Pisum sativum L.

Summary Soluble proteins of pea seed were investigated by quantitative immunological methods. Vicilin, legumin, pea seed lectin (PEA), 26 albumins and a globulin (B₁) were detected and observed during seed development, germination and under different extraction and fractionation procedures. Vicilin and legumin were found to be immunologically distinctly different. Legumin was found to be comprised of two similar proteins, Legumin species I and II. Vicilin, but no legumin, was detected in the embryonic axis.Three albumins, B₁ and PEA were found to be synthesized after the onset of legumin synthesis.Among the pea lines investigated, one line exhibited distinct differences with respect to the albumins and PEA.Some observations indicate that PEA might interact with other seed proteins of pea.     

Hexokinase Levels in Discrete Regions of Rat Brain: Evaluation by Quantitative Immuno fluoresence Using Interactive Laser Cytometry and Comparison with Basal Rates of Glucose Utilization

Relative levels of hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) have been determined in 16 discrete regions of adult rat brain by a quantitative immunofluorescence method. The distribution of immunofluorescence in brain sections was determined by interactive laser cytometry and related to hexokinase content by comparison with standard sections containing known amounts of the enzyme. In many of these regions, referred to here as group I regions, hexokinase content was correlated with previously reported basal rates of glucose utilization. However, several regions (group II regions) in which hexokinase content exceeded that expected from basal rates of glucose utilization were also detected. Compared with the corresponding regions from albino rat brain, higher hexokinase levels were found in the dorsal and ventral lateral geniculate (group I regions) of pigmented Norway rats, a result reflecting previously reported increased glucose utilization by these regions in pigmented rats. There was no difference in hexokinase levels in the superior colliculus, a group II structure, from albino and pigmented rats, a finding implying that a reported increase in rate of glucose utilization in the superior colliculus of pigmented rats is effected without an increase in hexokinase content. It is suggested that group II regions may be adapted to sustain increases in rates of glucose utilization that are, relative to basal rates, considerably greater than those experienced by group I regions.     

Autoradiographic Localization of Dopaminergic and Noradrenergic Receptors in the Bovine Pineal Gland

Dopamine and norepinephrine are involved in regulation of melatonin synthesis in the pineal gland. In bovine pineal gland, D1- and D2-dopaminergic and alpha 1-adrenergic receptors have been characterized pharmacologically in several laboratories, while beta 1-adrenergic receptors have been studied using physiological technique. The current study presents a quantitative autoradiographic analysis of these four dopaminergic and noradrenergic receptors in bovine pineal gland. The density order of the receptors is D1 greater than alpha 1 greater than D2 greater than or equal to beta 1. The Bmax of dopamine D1 receptors is about 5 to 6 times higher than the Bmax for alpha 1-adrenergic receptors and about 20 times higher than the Bmax values for beta 1-adrenergic and D2-dopaminergic receptors. Dopamine D1 receptors are significantly denser in the pineal cortex than in the medulla. Both dopamine receptors are more concentrated in the distal area than in the proximal area (close to the habenula), whereas both noradrenergic receptors are homogeneously distributed along the longitudinal axis. Only D1-dopaminergic receptors display a heterogeneous distribution between the superior and the inferior areas, being denser in the inferior area. The observation of a much higher concentration of D1-dopaminergic receptors relative to the other receptors suggests an important role for dopamine in the regulation of bovine pineal physiology.     

Power of different sampling strategies to detect quantitative trait loci variance effects

Summary Many studies have shown that segregating quantitative trait loci (QTL) can be detected via linkage to genetic markers. Power to detect a QTL effect on the trait mean as a function of the number of individuals genotyped for the marker is increased by selectively genotyping individuals with extreme values for the quantitative trait. Computer simulations were employed to study the effect of various sampling strategies on the statistical power to detect QTL variance effects. If only individuals with extreme phenotypes for the quantitative trait are selected for genotyping, then power to detect a variance effect is less than by random sampling. If 0.2 of the total number of individuals genotyped are selected from the center of the distribution, then power to detect a variance effect is equal to that obtained with random selection. Power to detect a variance effect was maximum when 0.2 to 0.5 of the individuals selected for genotyping were selected from the tails of the distribution and the remainder from the center.     

Statistical analysis of a linkage experiment in barley involving quantitative trait loci for height and ear-emergence time and two genetic markers on chromosome 4

Summary The quantitative traits height and ear-emergence date were analyzed in the F₂ progeny of a cross between a tall winter barley cultivar (Gerbel) and a short spring barley cultivar (Heriot). The trait distributions were found to be related to the genotypes at two biochemical loci, -amylase (Bmy1) and water-soluble protein (Wsp3), which are known to lie on the long arm of chromosome 4. Linkages between each trait and the markers were investigated using normal mixture models. The two parental phenotypes and the heterozygote phenotype of Bmy1 were distinguishable so the model could be used directly to estimate linkage between Bmy1 and a quantitative trait locus (QTL) for height (Height). The Gerbel homozygote and heterozygote phenotype of Wsp3 could not be distinguished and the model was adapted accordingly. The proportion of plants requiring vernalization was consistent with control by two independent genes acting epistatically, and a normal mixture model based on a two-gene hypothesis was fitted to the distribution of ear-emergence date to estimate linkage between the marker loci and a QTL for ear-emergence date (Vrn1). The parameters of each model were the recombination fraction between the marker locus and the QTL and the means and standard deviations associated with each QTL genotype; these were estimated by maximum likelihood. The fitted distributions correspond well to those observed and the order of the loci along the chromosome is inferred to be Height — Vrn1 — Bmy1 — Wsp3, with Wsp3 being the most distal.     

Genome modifications in protoplast-derived tobacco plants: Contents of repetitive DNA sequences

Plasticity of the tobacco genome was studied by testing the DNAs of protoplast-derived regenerants with three different repetitive DNA sequences by the method of quantitative DNA/DNA hybridizations. A large population of 91 regenerants belonging to 35 different protoclones was analysed and a high degree of heterogeneity in the contents of the different DNA repeats was detected. The contents of middle repetitive sequences of two types were more stable or changed in the same direction, while the highly repetitive sequence varied independently and displayed a significant reduction in comparison with the two other sequences. Comparing the variation within the subpopulations of plants of the same clonal origin and the variation among the protoclones led to a conclusion that the pre-existing DNA variability in the starting plant material and/or thein vitro stress during the very early stages of protoclone regeneration played a decisive role in the formation of modified genomes in regenerants.     

A morphometric analysis of regional differences in myotomal muscle ultrastructure in the juvenile eel (Anguilla anguilla L.)

Summary Subpopulations of fast and slow fibres within the trunk musculature of elvers were examined using morphometric analysis of electron micrographs. Fibre regions were characterised by their histochemical staining characteristics, and individual fibres located using a coordinate mapping system utilising morphological features as reference points. Percentages of fibre volume occupied by mitochondria, myofibrils, sarcoplasmic reticulum (S.R.), and T-system were determined in each of the fibre groups, along a transect from the skin to the vertebral column (fibres 1–14, respectively).The fine structure of slow (red) fibres (1–2 fibres deep) is relatively homogeneous throughout its range, giving mean values for mitochondria, 21.4%; myofibrils, 61.0%; S.R., 2.10%; T-system, 0.31%. The fibres are relatively small (204 m²) and the mitochondrial cristae poorly developed.In contrast, there is a marked heterogeneity in the ultrastructure of fast (white) fibres, dependent on both position and size. The moderately small (333 m²) superficial fast fibres (3–4 fibres deep) have a significantly higher mitochondrial content (7.6%) than the larger deep fibres (1.2%) (6–12 fibres deep, 775 m²). The mean fractional volumes occupied by myofibrils, S.R., and T-system in the deep fibres are: 80.4%, 5.95%, and 0.38%, respectively. Fibres < 100 m² constitute up to 5% of the fast muscle and have a significantly higher mitochondrial volume (4.3%), more glycogen granules, and a slightly lower volume of S.R. (5.57%) than larger fibres.It is suggested that metabolic subpopulations of fast fibres correspond to different stages of fibre growth. The relatively poorly developed S.R. of eel fast muscle is thought to be correlated with the low frequency, high amplitude nature of the propagated waveform found in anguilliform locomotion.     

Methods for the production of multi-marker strains

Summary The production of a multi-marker strain given a series of strains each carrying a single marker will require a considerable investment in time and resources when based on a series of formal crosses. Such strains can be produced rapidly and with only minimal resources by recurrent cycles of random mating and selection, with selection based on the number of desired alleles carried.     

Basis and extent of genetic variability among doubled haploid plants obtained by pollen culture in Nicotiana sylvestris

Summary All diploid plants (doubled-haploid plants: D.H.) regenerated by androgenesis from binucleated pollen grains in Nicotiana sylvestris differ genetically from the original line as far as morphological features and growth rates are concerned. This androgenic variation (A.V.) is under nuclear control and is transmitted continuously by some D.H. for at least four generations of selfing; other D.H. progenies segregate. Further androgeneses carried out on one single D.H. reveal a new variability and increase the drift from the original line. All results cannot be explained by the presence of residual heterozygosity in the original line, and we suggest that most of the A.V. could originate from changes that occur in the DNA of the vegetative pollen grain cell. D.H. resulting from endomitosis of the vegetative cell would be homozygous and stable, whereas D.H. resulting from nuclear fusion between a vegetative and a generative cell would be heterozygous and would segregate in seeds through succeeding generations.