Underdiagnosis and undertreatment of asthma in childhood.

A total of 179 Tyneside children who had suffered at least one episode of wheeze since school entry were seen at the age of 7. All but 14 had visited a doctor for chest symptoms, but a diagnosis of asthma had been offered to the parents of only 21 children, including three of the 56 children experiencing four to 12 wheezy episodes a year and 11 of the 31 children experiencing more than 12 episodes a year. Bronchodilator treatment was rarely offered in the absence of such a diagnosis, and two thirds of the children had never received a bronchodilator. Of the children experiencing four or more episodes a year, only a third had received bronchodilator drugs regularly, though half had lost more than 50 days from school because of wheeze. School absenteeism fell 10-fold in the 31 children finally offered continuous prophylactic treatment. Although many doctors had feared that use of the word "asthma" would cause anxiety, parents were uniformly relieved when given an explanation of their child''s recurrent wheeze. This study uncovered a disturbing amount of ill health in children that was easily rectified. Probably this same problem exists in other areas.     

Water sorption by human cells

Water sorption by powdered human callus was studied using a vacuum microbalance, X-ray powder diffraction and NMR relaxation. The sorption data were fitted to theoretical isotherms. At high relative vapour pressures an increase in the monolayer value was found which is probably related to the swelling of the material. Adsorption/desorption hysteresis is present below 0.75' relative vapour pressure (r.v.p.). Only a small increase in protein chain separation was observed on water uptake, indicating that the primary level of organization of the keratin is hardly affected. The effect of solvent extraction is to reduce the strength of water binding but to leave the monolayer values constant. Isosteric heats confirm the reduction in affinity for water on solvent extraction and show that totally extracted callus behaves as a mildly hydrophobic material. The results are consistent with a model in which the water binding properties of callus are determined by the presence of water soluble components which allow a monomolecular layer of water to be formed at low r.v.p. followed by physical multilayer formation.Adsorption of sodium dodecyl sulphate was found to increase the monolayer value while dodecyl trimethyl ammonium bromide left the monolayer value unchanged.The NMR relaxation behaviour of water in callus is very similar to that of water on human hair and wool fibres. An activation enthalpy of 48 kJ · mol⁻¹ was found for the T₂ relaxation and a very broad T₁ minimum was observed at about −20°C at an operating frequency of 45 MHz corresponding to a correlation time of 2.2 ns.     

Regional localization of human ecto-5′nucleotidase to chromosome 6q14–q21

Summary Human and mouse hybrids that contain fragments of human chromosome 6 as translocations were analysed for expression of ecto-5nucleotidase enzymic activity measured by the conversion of AMP to adenosine and for antigenicity recognized by a monoclonal antibody specific for the human isozyme. Both methods allow a regional assignment of ecto-5nucleotidase to 6q14–q21.     

Measurement of nasal patency in anesthetized and conscious dogs.

Experiments were undertaken to characterize a noninvasive chronic, model of nasal congestion in which nasal patency is measured using acoustic rhinometry. Compound 48/80 was administered intranasally to elicit nasal congestion in five beagle dogs either by syringe (0.5 ml) in thiopental sodium-anesthetized animals or as a mist (0.25 ml) in the same animals in the conscious state. Effects of mast cell degranulation on nasal cavity volume as well as on minimal cross-sectional area (A(min)) and intranasal distance to A(min) (D(min)) were studied. Compound 48/80 caused a dose-related decrease in nasal cavity volume and A(min) together with a variable increase in D(min). Maximal responses were seen at 90-120 min. Compound 48/80 was less effective in producing nasal congestion in conscious animals, which also had significantly larger basal nasal cavity volumes. These results demonstrate the utility of using acoustic rhinometry to measure parameters of nasal patency in dogs and suggest that this model may prove useful in studies of the actions of decongestant drugs.     

Injectable Polysaccharide Microcapsules for Prolonged Release of Minocycline for the Treatment of Periodontitis

Injectable polysaccharide microcapsules holding minocycline were fabricated from alginate and chitosan for the treatment of periodontitis. The microcapsules were examined for the release and degradation of minocycline, as well as antimicrobial activity. The microcapsules were biodegradable and released minocycline between 10 and 1000 μg ml⁻¹, which was higher than the usual therapeutic concentration (1–5 μg ml⁻¹), for up to 7 days. These microcapsules showed a statistically significant suppression of pathogenic bacteria, such as Prevotella intermedia causing periodontitis. The microcapsules are thus potentially useful for drug delivery for the treatment of periodontitis.     

Does cigarette smoking increase time to conception?

Data are reported on the relationship between cigarette smoking and other health-related behaviours and time to conception in a population-based sample of women who acted as a control group in a case-control study of twinning. Women who continued to smoke close to the time of conception took significantly longer to become pregnant than women who never smoked or stopped smoking before the year during which they attempted to conceive. A hierarchical regression analysis performed on time-to-conception data in women who continued to smoke in the year before conception provided weak evidence for a dose-response relationship between time to conception and number of cigarettes smoked per day. No significant relationships were found between time to conception and other health-related behaviours.     

Identification of a novel 1'-[5-((3,5-dichlorobenzoyl)methylamino)-3-(3,4-dichlorophenyl)-4-(methoxyimino)pentyl]-2-oxo-(1,4'-bipiperidine) as a dual NK(1)/NK(2) antagonist

A novel series of dual NK(1)/NK(2) receptor antagonists, based on the 2-oxo-(1,4'-bipiperidine) template, has been prepared. Compound 10R is a potent dual NK(1)/NK(2) antagonist and demonstrates excellent in vivo activity and good oral plasma levels in the dog.     

Recombination and the divergence of hybridizing species

The interplay between hybridization and recombination can have a dramatic effect on the likelihood of speciation or persistence of incompletely isolated species. Many models have suggested recombination can oppose speciation, and several recent empirical investigations suggest that reductions in recombination between various components of reproductive isolation and/or adaptation can allow species to persist in the presence of gene flow. In this article, we discuss these ideas in relation to speciation models, phylogenetic analyses, and species concepts. In particular, we revisit genetic architectures and population mechanisms that create genetic correlations and facilitate divergence in the face of gene flow. Linkage among genes contributing to adaptation or reproductive isolation due to chromosomal rearrangements as well as pleiotropy or proximity of loci can greatly increase the odds of species divergence or persistence. Finally, we recommend recombination to be a focus of inquiry when studying the origins of biological diversity.