Verina Waights

Sperm storage in females of the smooth newt (Triturus v. vulgaris L.): I. ultrastructure of the spermathecae during the breeding season

Sperm storage in cloacal spermathecae was studied in females of Triturus v. vulgaris collected early in the breeding season in southern England. Females collected in terrestrial situations, presumably unmated, were mated in the laboratory, and the ultrastructure of the transferred sperm and the spermathecae was observed at various intervals after mating. Sperm from a spermatophore cap lodged in a females cloacal orifice can migrate into spermathecae within 1 hr after mating. Spherical structures on the axial fibers of some sperm in the cap could indicate immaturity. Disorderly clusters of sperm from the cap are still present in the cloacal chamber 12 hr after mating but are absent 24 hr after mating. During storage, sperm often are in tangled masses in the spermathecal tubules. The sperm are coated with spermathecal secretions, and some sperm nuclei were observed embedded in the spermathecal epithelium. Little evidence for spermiophagy early in the breeding season was found. During oviposition, mazes of sperm occur external to the spermathecal orifices, and sperm may be released in this condition onto eggs as they pass through the cloaca. The tangled clusters in which sperm are found from pick-up to oviposition are hypothesized as an adaptation to reduce the effectiveness of sperm competition from the ejaculates of rival males. Additional studies, using the same protocol and covering the entire cycle of sperm storage, are necessary to enable interspecific comparisons leading to phylogenetic hypotheses. J. Exp. Zool. 283:51–70, 1999.

Vascularisation in adipose depots surrounding immune-stimulated lymph nodes

We report a change in the vascularisation of the adipose depots surrounding the popliteal lymph node that has, and the contralateral node that has not, been exposed to a simulated immune challenge. The percentage of the depot that consists of vessels, as measured by image analysis, decreases over a period of 2 d after immune stimulus, then increases in a biphasic manner over the next 2–3 wk. By 1 mo after the stimulus, the vascularisation has returned to baseline values. The adipose tissue surrounding both the stimulated and the unstimulated lymph nodes shows a similar pattern, but the unstimulated depot lags by 3–6 d in reaching its maximum vascularisation. These data support the hypothesis that perinodal adipose tissue is involved in peripheral immune responses.

The development of a homologous teleost insulin radioimmunoassay and its use in the study of adrenaline on insulin secretion from isolated pancreatic islet tissue of the rainbow trout, Salmo gairdinerii (R.).

A homologous teleost insulin radioimmunoassay (RIA) employing bonito insulin RIA components is described. The RIA sensitivity and specificity was sufficient to measure endogenous immunoreactive insulin (IRI) levels in trout serum, pancreatic islet tissue extract and in vitro culture medium. Adrenaline at 10(-6)M evoked a marked stimulation of basal insulin release from isolated islets; whereas adrenaline at 10(-10)M evoked an inhibition of basal insulin release.

Adreneric control of insulin release from isolated islet tissue in the rainbow trout, Salmo gairdneri R

Immunoreactive insulin levels (IRI) were measured by a homologous fish insulin radioimmunoassay. An in vitro pancreatic islet superfusion technique was employed to monitor the changes in IRI in the presence and absence of specific adrenergic agonists and antagonists. Exogenous adrenaline at low concentrations (10(-10) M) inhibited IRI release but evoked an IRI stimulation at high concentrations (10(-6) M). The stimulation of IRI by adrenaline is thought to involve beta-adrenoceptors located postsynaptically on the beta-cell membrane as the effect of adrenaline was mimicked by the beta-agonist, isoproterenol, and abolished by the beta-antagonist, propranolol. Phentolamine (an alpha-antagonist) potentiated the adrenergic stimulation of IRI, whereas yohimbine (an alpha 2-antagonist) was without effect. Phenylephrine (alpha 1-adrenoceptor agonist) inhibited IRI release suggesting the presence of alpha 1-inhibitory adrenoceptors which exert a modulatory influence on adrenaline-stimulated insulin release.

A blended design approach for pervasive healthcare: bringing together users, experts and technology

Pervasive healthcare is beginning to investigate how novel sensory technologies can be used to measure body movements and provide various forms of feedback. This position paper reflects on a blended design approach that uses a combination of technology inspiration, consultation with experts and user-centred design for the development of a personalized pervasive healthcare system to support stroke rehabilitation.