The dynamics of recovery and growth: how defoliation affects stored resources.

Growth rate varies widely among species and the trade-off between growth rate and storage or maintenance traits is a principal axis of variation between species. Many plant species have substantial root stores, but very little is known about how growth rate modifies responses of these stores to defoliation and other stresses. Species with different growth rates are predicted to respond in distinct ways, because of variation in the pre-defoliation allocation to storage. Here, we quantified the dynamics of stored carbohydrates in seven species with varying growth rate, following defoliation in a pot experiment. For faster growing species, there was significant reduction in carbohydrate concentration following defoliation, followed by relatively fast recovery, whereas for slower growing species, carbohydrate concentration levels remained relatively invariant across treatments. Results for total carbohydrates mirrored those for concentration, but were not as significant. Our findings were consistent with the idea that faster growing species respond more rapidly than slower growers to defoliation, through changes in carbohydrate pool concentrations. Growth rate as an indicator of life-history and ecological strategy may therefore be key to understanding post-defoliation recovery and storage strategies.

Immunohistological demonstration of CaV3.2 T-type voltage-gated calcium channel expression in soma of dorsal root ganglion neurons and peripheral axons of rat and mouse.

Previous behavioral studies have revealed that CaV3.2 T-type calcium channels support peripheral nociceptive transmission and electrophysiological studies have established the presence of T-currents in putative nociceptive sensory neurons of dorsal root ganglion (DRG). To date, however, the localization pattern of this key nociceptive channel in the soma and peripheral axons of these cells has not been demonstrated due to lack of isoform-selective anti-CaV3.2 antibodies. In the present study a new polyclonal CaV3.2 antibody is used to localize CaV3.2 expression in rodent DRG neurons using different staining techniques including confocal and electron microscopy (EM). Confocal microscopy of both acutely dissociated cells and short-term cultures demonstrated strong immunofluorescence of anti-CaV3.2 antibody that was largely confined to smaller diameter DRG neurons where it co-localized with established immuno-markers of unmyelinated nociceptors, such as, CGRP, IB4 and peripherin. In contrast, a smaller proportion of these CaV3.2-labeled DRG cells also co-expressed neurofilament 200 (NF200), a marker of myelinated sensory neurons. In the rat sciatic nerve preparation, confocal microscopy demonstrated anti-CaV3.2 immunofluorescence which was co-localized with both peripherin and NF200. Further, EM revealed immuno-gold labeling of CaV3.2 preferentially in association with unmyelinated sensory fibers from mouse sciatic nerve. Finally, we demonstrated the expression of CaV3.2 channels in peripheral nerve endings of mouse hindpaw skin as shown by co-localization with Mrgpd-GFP-positive fibers. The CaV3.2 expression within the soma and peripheral axons of nociceptive sensory neurons further demonstrates the importance of this channel in peripheral pain transmission.

Evolution of flowering decisions in a stochastic, density-dependent environment.

Demography is central to both ecology and evolution, and characterizing the feedback between ecology and evolution is critical for understanding organisms' life histories and how these might evolve through time. Here, we show how, by combining a range of theoretical approaches with the statistical analysis of individually structured databases, accurate prediction of life history decisions is possible in natural density-regulated populations undergoing large fluctuations in demographic rates from year to year. Our predictions are remarkably accurate and statistically well defined. In addition, we show that the predicted trait values are evolutionarily and convergence stable and that protected polymorphisms are possible.

Referrals to a voluntary sector cancer day care centre: a descriptive study.

In the UK, recent guidance on supportive and palliative care has acknowledged the contribution of voluntary organizations, including their role in palliative day care. Similarly, research has tended to focus exclusively on palliative day care as opposed to comparable care for people with cancer, regardless of prognosis. This paper describes a case record review study conducted at a nurse-led voluntary sector cancer day care centre. The study focused on referrals over a one-year period in terms of user demographics, referral sources/reasons and subsequent care given. It was found that 220 referrals (including 106 self-referrals) were made during the year. Of these, 70.9% were people with cancer and the remainder were carers/bereaved people. Those referred broadly reflected national statistics on age, gender and cancer diagnosis. Carers were rarely referred by professionals, few lived in inner-city neighbourhoods and some had no informal support. Non-specific referral reasons, such as 'support', tended to be translated into specific therapies, such as complementary therapies and counselling, at initial assessment. Care offered at the centre appeared to supplement and complement that provided by local statutory services. The study raised issues for practice and further research that may be relevant to those working in similar centres.

Gaining access to potential research participants.

A researcher who undertook a study involving informal carers of terminally ill cancer patients had difficulty accessing participants through primary care nurses. Many of the nurses approached were unable to function as autonomous professionals in facilitating access to subjects without a doctor's permission. Such attitudes can make it more difficult for research to achieve its objectives.

A complex of iron and nucleic acid catabolites is a signal that triggers differentiation in a freshwater protozoan.

The polymorphic ciliated protozoan Tetrahymena vorax can undergo differentiation from the microstomal form, which normally feeds on bacteria and other particulate matter, into the macrostomal cell type, which is capable of ingesting prey ciliates. The process is triggered by exposure of the microstome to an inducer contained in stomatin, an exudate of the prey. To establish the identity of the signal, stomatin was fractionated by combinations of cation exchange, HPLC, and TLC, and the fractions were assayed for biological activity. Although no single active fraction of purified inducer was obtained, all fractions with activity contained ferrous iron and the nucleic acid catabolites hypoxanthine (6-oxypurine) and uracil (2, 4-dioxopyrimidine), probably in a chelated form. The activity of synthetic complexes containing these three components is equivalent to stomatin. These results indicate a role for ferrous iron and its potential in chelated form to signal differentiation in certain protozoa and, perhaps, in other organisms as well.

Early determinants of lifetime reproductive success differ between the sexes in red deer.

In polygynous, sexually dimorphic species, sexual selection should be stronger in males than in females. Although this prediction extends to the effects of early development on fitness, few studies have documented early determinants of lifetime reproductive success in a natural mammal population. In this paper, we describe factors affecting the reproductive success of male and female red deer (Cervus elaphus) on the island of Rum, Scotland. Birthweight was a significant determinant of total lifetime reproductive success in males, with heavier-born males being more successful than lighter ones. In contrast, birthweight did not affect female reproductive success. High population density and cold spring temperatures in the year of birth decreased several components of fitness in females, but did not affect the breeding success of males. The results confirm the prediction that selection on a sexually dimorphic trait should be greater in males than in females, and explain the differential maternal expenditure between sons and daughters observed in red deer. Differences between the sexes in the effects of environmental and phenotypic variation on fitness may generate differences in the amount of heritable genetic variation underlying traits such as birthweight.

A qualitative analysis of the information needs of informal carers of terminally ill cancer patients.

This article discusses issues relating to information arising from a qualitative study of the experiences of informal carers of terminally ill cancer patients. Qualitative data analysis, drawing on methods of literary criticism, revealed that information was a key area in carers' experience. The findings are presented in the context of needing to provide individualized care to every family and deal with information needs relating to the illness and prognosis. The question of who is in possession of what information is raised, and the effect that this can have on couples is discussed, together with the issue of false information which carers may receive. The discussion centres on the complexity of understanding carers' information needs and considers how these are affected by the context within which carers operate. The work of Glaser and Strauss on awareness contexts is discussed in this respect. Finally, the importance of the nurse's role as a sensitive mediator of information is considered.

Perceptions related to time in a qualitative study of informal carers of terminally ill cancer patients.

Caring for a terminally ill relative is a complex, time-consuming experience. Demands on carers' time stem from a variety of sources, notably the practical and emotional work they must perform. Carers should be helped to plan their time effectively. Carers need to come to terms with their perceptions about past, present and future. Achieving some sense of equilibrium in the caring role is important. Professionals working with families experiencing terminal illness have a duty to assess each family individually in order to provide appropriate help and support.

Cohort variation in male survival and lifetime breeding success in red deer.

We investigated cohort differences in the lifetime breeding success and survival of male red deer Cervus elaphus L. in an increasing population on the Isle of Rum, Scotland. There were significant differences in survival through different stages of the life span between 15 cohorts of males, ranging between: 0.26-1.00, calf survival through first winter; 0.56-1.00, yearling survival; 0.44-0.94, adult survival. This variation in survival was related to environmental conditions in the cohorts' year of birth, whilst controlling for annual effects. For 10 cohorts of males with complete lifetime data, mean breeding success also varied significantly, between 0.83 and 3.86. This variation, too, was associated with environmental conditions in the cohorts' year of birth. Since in many sexually dimorphic mammals, the growth and survival of males is more strongly affected by adverse environmental conditions than that of females, we expected that cohort variation would be more extreme amongst males than females. This was true, for both cohort survival and reproduction. We expected to observe selection on cohort adult body size, related to survival or reproduction. However, there was no evidence of variation in adult body size between cohorts, nor for relationships between differences in body size between cohorts and measures of survival or breeding success. Cohorts which underwent high intial mortality subsequently experienced higher adult survival than cohorts not subjected to high density-related selection early in life.

Density-related changes in sexual selection in red deer.

In sexually dimorphic mammals, high population density is commonly associated with increased mortality of males relative to females and with female-biased adult sex ratios. This paper investigates the consequences of these changes on the distribution of male breeding success, the intensity of competition for females and the opportunity for sexual selection. After the red deer (Cervus elaphus L.) population of the North Block of Rum (Inner Hebrides) was released from culling, female numbers rose and male numbers declined, leading to an adult sex ratio of around one male to two females. This change was the result of increased mortality of males relative to females during the first two years of life; of increased emigration rates by young males; and of reduced immigration by males from outside the study area. The increasing bias in the adult sex ratio affected the timing of breeding as well as the distribution of mating success in males. As the adult sex ratio became increasingly biased towards females, the degree of skew in mating success (calculated across all harem-holders) increased, but mature males defended harems for shorter periods and a higher proportion of males held harems. In addition, a higher proportion of calves were fathered by immigrant males and the proportion fathered by males born in the study area declined. These results support the contention that, where high population density is associated with a female-biased adult sex ratio, competition for mates is likely to decline.

Pain management in advanced cancer.

This article explores the nurse's role in the management of pain for patients with advanced cancer. It relates to UKCC Professional Development categories: Care enhancement and Practice development.

Patient isolation in chronic benign pain.

Over the years, nurses, doctors and scientists have sought ways of assessing the impact of pain on patients. While many of the instruments devised have been extremely useful in identifying the nature and intensity of pain, defining the effect it has on people's lives and perceptions has proved much more problematic. Based on the work she carried out with patients suffering from chronic benign pain, Karen Rose explores one aspect of these effects--the feeling of isolation. By using a four-step anthropological approach to identify the impact of pain, she argues, nurses can arrive at a realistic and accurate assessment of how patients are coping.

An issue of powerlessness. Psychosocial issues affecting breast cancer care.

Not all hospitals employ breast care nurses, and many women with breast cancer feel compelled to accept the treatment option which they perceive their surgeon or partner to prefer. This is an important situation where nurses can act as patient advocate and help redress the balance.

Beta-lactamase is encoded on plasmid pACK3 in Staphylococcus simulans biovar staphylolyticus.

Staphylococcus simulans biovar staphylolyticus, the lysostaphin-producing organism, contains five plasmids designated pACK1 through pACK5. Hybridization analysis using cloned beta-lactamase gene (bla) as probe and characterization of cured strains revealed that bla resides on pACK3 rather than on the lysostaphin endopeptidase plasmid (pACK1) as reported by others.

Plasmid-encoded lysostaphin endopeptidase resistance of Staphylococcus simulans biovar staphylolyticus.

Staphylococcus simulans biovar staphylolyticus, the lysostaphin-producing organism, secretes a staphylolytic endopeptidase (EC 3.4.99.17) that is encoded on plasmid pACK1. Susceptibility of pACK1-cured strains to lysis by endopeptidase established that resistance to this enzyme is not an inherent property of the organism but rather is encoded on this dispensable plasmid. Furthermore, the enzyme is not an autolysin that is essential for cell wall synthesis because strains lacking the endopeptidase gene grew normally.