Adenosine 5′-triphosphate (ATP) is known to play a significant role as a neurotransmitter in smooth muscle. There is evidence to show that ATP can cause bladder contractions and may also be involved in the processing of sensory information in the urinary bladder. These effects are likely to be mediated by P2X receptors, namely P2X₁ and P2X₃, respectively. This study set out to investigate their distribution in rat and human urinary bladders. P2X₁ receptor immunoreactivity was found on detrusor muscle fibres and P2X₃ receptor immunoreactivity was found in the urothelium of both species. This is the first demonstration of a non-neuronal localisation for P2X₃ receptors. No clear evidence was found for the presence of P2X₃ receptors on calcitonin gene-related peptide-containing sensory nerves and therefore P2X₃ receptors may not have a direct role in the mediation of sensory responses to ATP in the urinary bladder.

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The treatment of plastic contact developed in this paper is based on three physical observations: that the total volume of metal is not changed by plastic deformation; that the mean indentation pressure is a well-defined material constant applicable to the whole range of likely asperity shapes; and that the displaced material reappears as a uniform rise in the non-contacting surface. An energy-balance argument is used to obtain dimensionless relations between the load, separation, and degree of contact, in terms of the height distribution of the surface. A fourth observation is then added: that the height distributions of many engineering surfaces are, to a good approximation, Gaussian. The relations are worked out in detail for this height distribution and compared with experimental observations. The treatment accurately predicts the behaviour up to extremely high loads; and accounts for the remarkable persistence of asperities on rough surfaces in plastic contact. The argument, and the main supporting experiments, were conceived in terms of the contact of a uniformly loaded nominally flat surface, but the extention to local indentations is quite straightforward. It is shown that for local indentations in homogeneous bodies the real area of contact is always one half of the nominal area. This unexpected result is in fact accurately confirmed by experiment. The treatment also discusses the effect of a hard or soft surface layer on the indented body, and again the predictions are supported by practical measurements.

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Summary A new anti‐oestrogen, tamoxifen, has been synthesized and is available for clinical trials. Its value in the treatment of anovulatory infertility has been assessed in 32 patients. A total of 26 patients apparently ovulated, 16 patients conceived during a treatment cycle, and 2 patients became pregnant during the first spontaneous cycle thereafter. There was no increase in the abortion rate and there were no multiple pregnancies. Side‐effects were uncommon and none were serious.