Pitfalls of using estimations of glomerular filtration rate in an intensive care population.

BACKGROUND: Accurate knowledge of the glomerular filtration rate (GFR) is imperative in the intensive care unit (ICU) as renal status is important for medical decisions, including drug dosing. AIMS: Recently, an estimation of GFR (eGFR) was suggested as a method of estimating GFR. How well this formula predicts GFR in unwell patients with normal initial serum creatinine concentrations has not been examined. METHODS: The accuracy of the eGFR (before and after adjustment for actual body surface area (BSA)) was compared with measured and with estimated creatinine clearance using the Cockcroft Gault (CG) formula adjusted for total and lean body weight. RESULTS: A total of 237 observations was recorded in 47 subjects. These were initially analysed independently, and then using the first observation only. Overall the mean difference between measured creatinine clearance and eGFR was -12 mL/min (95% confidence interval (CI) -20 to -3), between measured creatinine clearance and CG +17 mL/min (95% CI 9-24), between measured creatinine clearance and CG adjusted for ideal body weight +12 mL/min (95% CI 4-21) and between measured creatinine clearance and eGFR 'unadjusted' for BSA 5 mL/min (95% CI -2-13). CONCLUSIONS: Using either eGFR or CG formulae to estimate renal function in ICU subjects with normal serum creatinine concentrations is inaccurate. Although correcting for BSA improves the eGFR, this requirement to measure height and weight removes a major attraction for its use. We suggest that eGFR should not be automatically calculated in the ICU setting.

Genetic diversity and differentiation processes in the ploidy series of Olea europaea L.: a multiscale approach from subspecies to insular populations.

Geographical isolation and polyploidization are central concepts in plant evolution. The hierarchical organization of archipelagos in this study provides a framework for testing the evolutionary consequences for polyploid taxa and populations occurring in isolation. Using amplified fragment length polymorphism and simple sequence repeat markers, we determined the genetic diversity and differentiation patterns at three levels of geographical isolation in Olea europaea: mainland-archipelagos, islands within an archipelago, and populations within an island. At the subspecies scale, the hexaploid ssp. maroccana (southwest Morocco) exhibited higher genetic diversity than the insular counterparts. In contrast, the tetraploid ssp. cerasiformis (Madeira) displayed values similar to those obtained for the diploid ssp. guanchica (Canary Islands). Geographical isolation was associated with a high genetic differentiation at this scale. In the Canarian archipelago, the stepping-stone model of differentiation suggested in a previous study was partially supported. Within the western lineage, an east-to-west differentiation pattern was confirmed. Conversely, the easternmost populations were more related to the mainland ssp. europaea than to the western guanchica lineage. Genetic diversity across the Canarian archipelago was significantly correlated with the date of the last volcanic activity in the area/island where each population occurs. At the island scale, this pattern was not confirmed in older islands (Tenerife and Madeira), where populations were genetically homogeneous. In contrast, founder effects resulted in low genetic diversity and marked genetic differentiation among populations of the youngest island, La Palma.

Genome size diversity in orchids: consequences and evolution.

BACKGROUND: The amount of DNA comprising the genome of an organism (its genome size) varies a remarkable 40 000-fold across eukaryotes, yet most groups are characterized by much narrower ranges (e.g. 14-fold in gymnosperms, 3- to 4-fold in mammals). Angiosperms stand out as one of the most variable groups with genome sizes varying nearly 2000-fold. Nevertheless within angiosperms the majority of families are characterized by genomes which are small and vary little. Species with large genomes are mostly restricted to a few monocots families including Orchidaceae. SCOPE: A survey of the literature revealed that genome size data for Orchidaceae are comparatively rare representing just 327 species. Nevertheless they reveal that Orchidaceae are currently the most variable angiosperm family with genome sizes ranging 168-fold (1C = 0.33-55.4 pg). Analysing the data provided insights into the distribution, evolution and possible consequences to the plant of this genome size diversity. CONCLUSIONS: Superimposing the data onto the increasingly robust phylogenetic tree of Orchidaceae revealed how different subfamilies were characterized by distinct genome size profiles. Epidendroideae possessed the greatest range of genome sizes, although the majority of species had small genomes. In contrast, the largest genomes were found in subfamilies Cypripedioideae and Vanilloideae. Genome size evolution within this subfamily was analysed as this is the only one with reasonable representation of data. This approach highlighted striking differences in genome size and karyotype evolution between the closely related Cypripedium, Paphiopedilum and Phragmipedium. As to the consequences of genome size diversity, various studies revealed that this has both practical (e.g. application of genetic fingerprinting techniques) and biological consequences (e.g. affecting where and when an orchid may grow) and emphasizes the importance of obtaining further genome size data given the considerable phylogenetic gaps which have been highlighted by the current study.

Molecular systematics of Gagea and Lloydia (Liliaceae; Liliales): implications of analyses of nuclear ribosomal and plastid DNA sequences for infrageneric classification.

BACKGROUND AND AIMS: Gagea is a Eurasian genus of petaloid monocots, with a few species in North Africa, comprising between 70 and approximately 275 species depending on the author. Lloydia (thought to be the closest relative of Gagea) consists of 12-20 species that have a mostly eastern Asian distribution. Delimitation of these genera and their subdivisions are unresolved questions in Liliaceae taxonomy. The objective of this study is to evaluate generic and infrageneric circumscription of Gagea and Lloydia using DNA sequence data. METHODS: A phylogenetic study of Gagea and Lloydia (Liliaceae) was conducted using sequences of nuclear ribosomal internal transcribed spacer (ITS) and plastid (rpl16 intron, trnL intron, trnL-F spacer, matK and the psbA-trnH spacer) DNA regions. This included 149 accessions (seven as outgroups), with multiple accessions of some taxa; 552 sequences were included, of which 393 were generated as part of this research. KEY RESULTS: A close relationship of Gagea and Lloydia was confirmed in analyses using different datasets, but neither Gagea nor Lloydia forms a monophyletic group as currently circumscribed; however, the ITS and plastid analyses did not produce congruent results for the placement of Lloydia relative to the major groups within Gagea. Gagea accessions formed five moderately to strongly supported clades in all trees, with most Lloydia taxa positioned at the basal nodes; in the strict consensus trees from the combined data a basal polytomy occurs. There is limited congruence between the classical, morphology-derived infrageneric taxonomy in Gagea (including Lloydia) and clades in the present phylogenetic analyses. CONCLUSIONS: The analyses support monophyly of Gagea/Lloydia collectively, and they clearly comprise a single lineage, as some previous authors have hypothesized. The results provide the basis for a new classification of Gagea that has support from some morphological features. Incongruence between plastid and nuclear ITS results is interpreted as potentially due to ancient hybridization and/or paralogy of ITS rDNA.

Within-population spatial genetic structure in four naturally fragmented species of a neotropical inselberg radiation, Alcantarea imperialis, A. geniculata, A. glaziouana and A. regina (Bromeliaceae).

Studies of organisms on 'terrestrial islands' can improve our understanding of two unresolved issues in evolutionary genetics: the likely long-term effects of habitat fragmentation and the genetic underpinnings of continental species radiations in island-like terrestrial habitats. We have addressed both issues for four closely related plant species of the adaptive radiation Bromeliaceae, Alcantarea imperialis, A. geniculata, A. regina and A. glaziouana. All four are adapted to ancient, isolated inselberg rock outcrops in the Brazilian Atlantic rainforest and are thus long-term fragmented by nature. We used eight nuclear microsatellites to study within-population spatial genetic structure (SGS) and historical gene dispersal in nine populations of these species. Within-population SGS reflected known between-species differences in mating systems. The strongest SGS observed in A. glaziouana (Sp=0.947) was stronger than literature estimates available for plants. Analysis of short- and long-distance components of SGS identified biparental inbreeding, selfing and restricted seed dispersal as main determinants of SGS, with restricted pollen dispersal by bats contributing in some localities. The ability of Alcantarea spp. to colonize isolated inselbergs probably stems from their flexible mating systems and an ability to tolerate inbreeding. Short-ranging gene dispersal (average sigma=7-27 m) is consistent with a loss of dispersal power in terrestrial island habitats. Population subdivision associated with sympatric colour morphs in A. imperialis is accompanied by between-morph differences in pollen and seed dispersal. Our results indicate a high potential for divergence with gene flow in inselberg bromeliads and they provide base-line data about the long-term effects of fragmentation in plants.

A preliminary study of genetic variation in populations of Monstera adansonii var. klotzschiana (Araceae) from North-East Brazil, estimated with AFLP molecular markers.

BACKGROUND AND AIMS: This study sought genetic evidence of long-term isolation in populations of Monstera adansonii var. klotzschiana (Araceae), a herbaceous, probably outbreeding, humid forest hemi-epiphyte, in the brejo forests of Ceará (north-east Brazil), and clarification of their relationships with populations in Amazonia and the Atlantic forest of Brazil. METHODS: Within-population genetic diversity and between-population dissimilarity were estimated using AFLP molecular markers in 75 individuals from eight populations located in Ceará, the Brazilian Atlantic Forest and Amazonia. KEY RESULTS: The populations showed a clinal pattern of weak genetic differentiation over a large geographical region (F(ST) = 0.1896). A strong correlation between genetic and geographical distance (Mantel test: r = 0.6903, P = 0.002) suggests a historical pattern of isolation by distance. Genetic structure analysis revealed at least two distinct gene pools in the data. The two isolated Ceará populations are significantly different from each other (pairwise Phi(PT) = 0.137, P = 0.003) and as diverse (Nei's gene diversity, average H(e) = 0.1832, 0.1706) as those in the Atlantic and Amazon forest regions. The population in southern Brazil is less diverse (Nei's gene diversity, average H(e) = 0.127) than the rest. The Ceará populations are related to those of the Atlantic forest rather than those from Amazonia (AMOVA, among-groups variation = 11.95 %, P = 0.037). CONCLUSIONS: The gene pools detected within an overall pattern of clinal variation suggest distinct episodes of gene flow, possibly correlated with past humid forest expansions. The Ceará populations show no evidence of erosion of genetic diversity, although this was expected because of their isolation. Their genetic differentiation and relatively high diversity reinforce the importance of conserving the endangered brejo forests.

Persistence of DNA adducts, hypermutation and acquisition of cellular resistance to alkylating agents in glioblastoma.

Glioblastoma is a lethal form of brain tumour usually treated by surgical resection followed by radiotherapy and an alkylating chemotherapeutic agent. Key to the success of this multimodal approach is maintaining apoptotic sensitivity of tumour cells to the alkylating agent. This initial treatment likely establishes conditions contributing to development of drug resistance as alkylating agents form the O6-methylguanine adduct. This activates the mismatch repair (MMR) process inducing apoptosis and mutagenesis. This review describes key juxtaposed drivers in the balance between alkylation induced mutagenesis and apoptosis. Mutations in MMR genes are the probable drivers for alkylation based drug resistance. Critical to this interaction are the dose-response and temporal interactions between adduct formation and MMR mutations. The precision in dose interval, dose-responses and temporal relationships dictate a role for alkylating agents in either promoting experimental tumour formation or inducing tumour cell death with chemotherapy. Importantly, this resultant loss of chemotherapeutic selective pressure provides opportunity to explore novel therapeutics and appropriate combinations to minimise alkylation based drug resistance and tumour relapse.

Growth of ferns from spores in axenic culture.

In this chapter, a method by which many fern species can be successfully grown from spores in axenic culture will be described. Unlike the conventional method of sowing the spores on compost, this method allows spore populations free from contamination by spores of other species to be sown. The method can be used for the production of mature sporophytes or to provide a controllable system for biosystematic studies of, or experimentation with, fern gametophytes (1,2).

Vegetative propagation of cacti and other succulents in vitro.

Maintenance of collections of succulent plants can be problematic, since many of these species are very susceptible to rots caused by bacteria and fungi. Rooting and establishment of cuttings can also be difficult. At Kew, methods for themicropropagation of cacti and other succulents have been developed over the last 10 yr. These have proved to be very useful for overcoming the problems mentioned above.

In vitro propagation of Litsea cubeba (Lours.) Pers., a multipurpose tree.

A rapid clonal propagation system has been developed for Litsea cubeba. Following investigation of a range of cytokinins and a variety of explant sources (shoot tip, node, leaf and petiole) it was established that 6-benzyladenine with shoot tip explants gave optimal multiple-shoot induction. In vitro rooting on growth-regulator-free medium was possible and over 100 plantlets were successfully weaned to the glasshouse.

Issues of latex safety in dentistry.

The prevalence of reported reactions to natural rubber latex products in both the general population and in dental personnel appears to parallel the rise in glove wearing by health professionals. This paper reviews the irritant and allergic reactions which may be associated with latex products, particularly gloves. The aetiology, pathogenesis, diagnosis and management of immediate Type I (IgE mediated) responses to latex are described in some detail. The paper provides the reader with an insight into factors that may lead to latex allergy and outlines measures for handling 'latex sensitised' individuals in the dental surgery.

Risk analysis as the basis for surgical glove selection.

The growing use of outcomes research will have a significant effect on the way surgeons make decisions concerning glove product selection. These effects will be both direct and indirect, as payers begin to use outcome data to develop practice guidelines. to reduce morbidity and mortality rates, and to alleviate long-term cost and consequences of acquired latex allergy or powder-related postoperative complications in patients. This article reviews elements of risk associated with surgical gloves.

Scientific assay methods as the basis for glove selection.

Allergies to latex proteins and glove chemicals are increasing in the clinical practice setting. Inasmuch as latex is ubiquitous in the health environment, individuals may be exposed to latex antigens by a number of different routes, including compromised skin, mucous membranes of the respiratory and urogenital tracts, and internally during surgery. As demonstrated by numerous research articles, the key factors that appear to play a role in acquired latex hypersensitivity are chemicals used in the manufacture of products; the level of residual latex proteins, and the presence of glove powder, which binds latex protein. Currently, devices and materials containing latex are not labeled, although this may be rectified by the FDA in the near future. Until products are labeled, it is important for physicians to familiarize themselves with the routes of sensitization, variations in assay methods, and the type and amount of allergen in products in order to select the safest product for patient use and personal protection.

Peritoneal healing with adhesion formation: current comment.

Intra-abdominal adhesions are fibrotic structures, which lie in the form of a string or attachment between the abdominal organs and connect these together. They are responsible for serious clinical complications that include intestinal obstruction, infertility, and pelvic pain. During the last century, surgeons' comprehensive understanding of the biology of peritoneal healing and wound repair has allowed them to identify a variety of new therapeutic techniques that limit the development of adhesion formation. New drugs, dextran 70 and poloxamer 407, have been developed to prevent adhesion formation. In addition, three new biomaterials (oxidized regenerated cellulose, hyaluronate membrane, and polytetrafluoroethylene) are synthetic barriers being used to prevent adhesions.

Drainage systems. Their role in wound healing.

In recent years, studies have demonstrated that the risk of wound infection can be reduced by careful wound management and adequate wound drainage. Evidence indicates that if a wound is not allowed to drain freely, blood, body fluids, pus, and necrotic material will collect in the wound, providing a growth medium for microorganisms. Surgical wound drainage is recognized as a key element in facilitating the healing process. Wound drainage systems are designed to allow enough moisture to remain in tissues to promote regeneration and lessen inflammation, while removing excess exudate or material that may hamper the healing process. Regardless of the system selected, it must be able to apply enough negative pressure to maintain surface apposition in the healing wound. This requires careful nursing assessment to ensure constancy of vacuum pressure. As the cost of treating preventable infections increases, infection control is becoming a high priority. Health care workers have therefore become increasingly interested in any product or system that contributes to the prevention of costly surgical wound infections.

Hand dermatitis. The role of gloves.

The wide range of problems that occur in association with occupational skin exposure has brought into focus the need to understand the role of allergens in skin disease. Their impact on health, their role in the causation of skin disease, and the measures that can be instituted to regulate, control, and prevent skin problems are receiving increased attention by OR managers because of the associated costs of skin reactions in OR nurses and the inherent dangers associated with latex allergy. Latex gloves have become a standard part of OR attire, and even though they serve as the primary form of hand protection in the OR, gloves also may serve as one of the key causes of contact or allergic dermatitis in OR personnel. The high frequency of latex glove allergy, especially in OR nurses and surgeons, focuses attention on the need to evaluate the type and quality of surgical latex gloves selected for use. When instances of new skin reactions appear in nursing personnel. OR managers should look for recent changes in glove brands, scrub products, or antimicrobial agents as possible trigger allergens. In such circumstances, managers may wish to use hypoallergenic products as a solution. Although hypoallergenic and/or powder-free gloves or scrub products may be more costly on a unit basis, when compared to the time lost from work, physical discomfort of the worker, and the expense of treatment, they are really quite a bargain.

Medical waste. The growing issues of management and disposal.

When addressing the impact of medical waste management and regulatory controls on the health care industry, it is important to remember that as long as modern medicine continues to maintain and sustain its current quality of life and wellness standards, industry will continue to generate various byproducts that have adverse effects on both people and the environment. It is important, therefore, to carefully evaluate the impact of societal demands. Unless government, industry, environmental groups, and health care providers abandon their current adversarial relationships and work together to solve shared problems, there will be no improvement in the growing problem of medical waste. The long-term solutions to today's growing waste problems depend to a great extent on human factors and the willingness of industry, medical community, and governmental bodies to cooperate with each other, recognizing the cause-effect relationship of a continued demand for disposable products. There are many pieces to the waste management puzzle. Obviously, surgeons cannot perform surgery without exposure to blood, tissue or body fluids, and nurses cannot maintain asepsis without sterile products. Because the health care team cannot totally eliminate the source of medical waste, they must learn to more effectively manage and control it. Health care professionals must encourage industry and government to work together to develop standards for products and materials used as barriers and use more biodegradable materials. Health care facilities must learn to minimize the amount of medical waste designated as regulated or infectious. Segregating potentially infectious material from clean waste at the point of generation may reduce both volume and cost.

The effect of surgical glove powder on proliferation of human skin fibroblast and monocyte/macrophage.

The effect of surgical glove powders (Biosorb, Keoflo, and CaCO3) and Hydrocote (powder-free lubricating agent, Biogel) was examined on human skin fibroblasts and monocyte/macrophage cell lines (U937 and HL-60). Glove powders (0.1-100 micrograms/ml) in the presence of 10% fetal bovine serum (FBS) had no significant effect on the rate of 3H-thymidine uptake and proliferation of these cells after 48 h and 7 days of exposure, respectively. However, they inhibited HL-60 growth after 10 days, and Biosorb and CaCO3 inhibited U937 after 10-21 days of exposure compared with control. In the presence of low serum (0.5%), Biosorb, but not Keoflo, CaCO3, and Hydrocote, inhibited HL-60 cells after the third day of exposure (p < 0.05), whereas they were without any effect on U937 cells. Further incubation resulted in a significant decrease in cell density in all treatments, as well as controls, because of cell death. In the presence of 2% serum, glove powder-treated HL-60 significantly increased in cell numbers during the first 3 days, and the cells became stationary thereafter, whereas Keoflo and CaCO3-stimulated U937 reached a maximal by 9 days of treatment. Coculturing of fibroblasts directly with macrophages (0.4-5 x 10(5) cells per dish) or incubation with macrophage culture-conditioned media (CCM) stimulated quiescent fibroblast growth equal to that induced by 10% and 0.5% serum, respectively (p < 0.05). However, incubation of fibroblasts with glove powder-treated HL-60 CCM (except CaCO3) inhibited (p < 0.05) and CCM from Biosorb-treated U937 stimulated (p < 0.05) fibroblast proliferation. The CCM from glove powder-treated HL-60 and U937 did not have any significant effect on the rate of 3H-thymidine incorporation into fibroblasts compared with controls. The present observations suggest that glove powder action on fibroblast and macrophage growth in vitro depends on both the serum concentration of the culture medium and the length of exposure. The results imply that glove powders may have an adverse effect in vivo by directly influencing the biologic activity of macrophages, as well as other cell types, leading to alterations in the early phases of wound healing.