Tissue viability nurses' experiences of managing wound exudate.

Wound exudate presents several challenges for patients and nurses. The description of exudate volume, colour and viscosity varies greatly, often depending on the personal preference of the nurse. When the nature and volume of exudate has been described, management of exudate presents its own issues in terms of ensuring that the appropriate dressing or intervention is selected and used effectively. This article reports on the outcomes of a series of discussion groups held to explore the difficulties tissue viability nurse specialists experience in relation to advising non-specialist nurses about wound exudate in the practice setting.

Radiotherapy-induced skin reactions: assessment and management.

Radiotherapy, the use of high-energy rays to either kill cancer cells or treat some benign tumours, is undoubtedly a positive intervention. However, as the primary mode of action in radiotherapy treatment is the killing of cells to prevent replication, other non-cancerous cells may be affected. For example, up to 85% of patients will experience some form of skin reaction, which will range from local erythema to moist desquamation. Such reactions are not only distressing and painful for the patient, if severe enough, they may warrant a halt in treatment. This article outlines the aims and nature of radiotherapy, and then discusses the aetiology of skin reactions, risk factors for reaction, and assessment tools. Management interventions will also be shown, with emphasis on silicone dressings.

VARIATION IN THE MATING SYSTEM OF EICHHORNIA PANICULATA (SPRENG.) SOLMS. (PONTEDERIACEAE).

A multilocus procedure was used to estimate outcrossing rates from allozyme data in nine populations of Eichhornia paniculata from NE Brazil and Jamaica. The populations were chosen to represent stages in a proposed model of the evolutionary breakdown of tristyly to semi-homostyly; they differed in morph structure (trimorphic, dimorphic, or monomorphic) and floral traits likely to influence the mating system. The interpopulation range in outcrossing rate, t, was 0.96-0.29. Two additional populations from Jamaica, composed exclusively of self-pollinating, semi-homostylous, mid-styled plants, were invariant at 21 isozyme loci, precluding estimates of outcrossing frequency. Trimorphic populations from Brazil had uniformly high outcrossing rates of 0.96-0.88. Values for the floral morphs within populations were not significantly different. A controlled pollination experiment, comparing the competitive ability of self and cross pollen using the Got-3 marker locus, provided evidence that the maintenance of high outcrossing rates in trimorphic populations results from the prepotency of cross pollen and/or the selective abortion of selfed zygotes. Morph-dependent variation in t was detected within a dimorphic population with the L morph outcrossing with a frequency of 0.76 in comparison with 0.36 in the M morph. The difference in the mating system of floral morphs results from modifications in position of short-level stamens in flowers of the M morph resulting in automatic self-pollination. The occurrence of E. paniculata populations composed exclusively of self-pollinating, mid-styled variants is thought to be associated with the spread of genes modifying stamen position. The high level of self-fertilization demonstrated in the M morph would allow automatic selection of these genes, augmented by fertility assurance in the absence of specialized pollinators.

ON THE DARWINIAN HYPOTHESIS OF THE ADAPTIVE SIGNIFICANCE OF TRISTYLY.

Darwin proposed that the function of the stamen-style polymorphism in heterostylous plants is to increase the probability of legitimate (compatible) pollinations among the floral morphs. Conspicuous pollen trimorphism in tristylous Pontederia cordata enables a test of the hypothesis. Comparison of the composition of pollen loads in naturally pollinated stigmas of intact and emasculated flowers were made at a population in Paugh Lake, Ontario, which was visited primarily by bumblebees. The magnitude of legitimate pollination was analyzed by ANOVA. In intact flowers, significant legitimate pollination was detected in the long-styled morph only. Following emasculation legitimate pollination was evident in the long- and short-styled morphs, with the mid-styled morph just short of displaying significant legitimate pollination. Similar results were obtained by chi-square analysis. It has been suggested that heterostyly may reduce mutual interference between maternal and paternal reproductive function. Two aspects of pollen-stigma interference were investigated in P. cordata. The potential importance of stigmatic or stylar clogging by incompatible pollen was examined by controlled field pollinations and measurements of seed set. The results indicate that prior application of large amounts of incompatible pollen has no significant effect on the seed set of open-pollinated inflorescences. Comparison of legitimate pollen capture in intact and emasculated flowers provided no evidence that the presence of stamens within flowers of the floral morphs interferes with the receipt of legitimate pollen. Pollen-stigma interference remains to be demonstrated in heterostylous plants.