bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival rates, causes of failure and productivity of Skylark Alauda arvensis nests on lowland farmland
Authors: Donald P. F. , Evans A. D. , Muirhead L. B. , Buckingham D. L. , Kirby W. B. , Schmitt S. I. A.
Published: March 2003

This paper analyses data from 995 Skylark Alauda arvensis nests found on lowland farms in southern England from 1996 to 1998. The majority of recorded nest failures were caused by predation except in agricultural grass, where trampling and agricultural operations were equally important. Nest survival rates varied between crop types, nests in cereals being around twice as likely to succeed as nests in grass or set‐aside. In cereals, nest survival rates increased with increasing distance from the nearest tramline and declined over the course of the breeding season. Predator control also had a significant independent effect on nest survival rates. On one farm where many other factors were held constant, a highly significant increase in nest survival rates from 12.3% to 40.7% coincided with the introduction of intensive predator control, which also appeared to bring forward mean laying dates. Most environmental factors explaining significant variation in nest survival rates did so only at the chick stage. The mean number of chicks produced per nesting attempt was 1.26 in cereals, 0.78 in set‐aside and 0.63 in grass, the differences being due primarily to variation in nest survival rates. Low densities of Skylark territories in cereal crops are not therefore the consequence of low breeding success at the scale of the individual nest and probably reflect limitations on the number of attempts made in a season. Measures taken to improve the attractiveness of cereal crops as a nesting habitat for Skylarks, and beneficial changes in grassland management, are likely to increase overall productivity.
Rigid gas permeable contact lens and corneal topography
Authors: Yebra‐Pimentel E. , Giráldez M. J. , Arias F. L. , González J. , González J. M. , Parafita M. A. , Febrero M.
Published: March 2003

We investigated the effect of high Dk daily wear rigid gas permeable contact lenses on corneal topography. Eight young myopic subjects wore hard contact lenses for 21 days. Corneal topography was monitored using the EyeSys system. It was measured every day during the next 21 days after the fitting. We recorded the corneal radius of curvature at 16 peripheral points approximately 1, 2, 3 and 4 mm along the four principal meridians (nasal, superior, inferior and temporal). Our study showed that daily wear RGP Forum 210 does not produce significant alterations of the corneal curvature as a function of time.
Intraocular pressure after excimer laser myopic refractive surgery
Authors: Montés‐Micó Robert , Neil Charman W.
Published: March 2003

The aim of this study was to determine whether intraocular pressure (IOP), as measured by Goldmann applanation or non‐contact tonometry, shows systematic changes in patients who have undergone photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK). IOP was measured by central Goldmann and non‐contact tonometry in 54 patients pre and post‐PRK, and in 43 patients pre‐ and post‐LASIK. An interval of 12 months was allowed after surgery. Patients were selected to have one of four specific initial values of refractive error (−2.5, −5.0, −7.5 and −10.0 D). Fellow unoperated eyes were used as controls. A paired Student's t‐test and a one‐way ANOVA test were used for statistical analysis. After PRK and LASIK, a statistically significant decrease (p<0.01) was observed in the IOP of the treated eyes (but not for control eyes; p>0.01). Although the magnitude of the change increased with the attempted refractive correction, this trend was not statistically significant ( >p>0.01). No statistically significant differences were found between the results obtained following the two types of surgery, although the recorded fall in IOP was smaller following LASIK( >p>0.01). The IOP measured after PRK and LASIK for myopia may be reduced because of reduced corneal thickness and curvature and, possibly, tissue softening after natural healing. The presence or absence of Bowman's membrane does not appear to be important in this context. The reduction in measured IOP following refractive surgery, by about 0.5 mmHg/D of myopic correction, needs to be remembered when possible abnormality of IOP in such patients is being considered.
Economic costs of cataract surgery using a rigid and a foldable intraocular lens*
Authors: Afsar Asfa J. , Woods Russell L. , Patel Sudi , Rogan Fiona , Wykes William
Published: March 2003

Optimal delivery of healthcare requires consideration of various costs. A foldable intraocular lens (IOL) is more expensive than an equivalent rigid IOL. However, surgical and post‐operative costs may make a foldable IOL economically preferable. We compared the economic costs of cataract surgery plus implantation of a foldable IOL with implantation of a rigid IOL. Prospective audit of the clinical records of 82 pseudophakes; 39 implanted with a rigid IOL and 43 implanted with a foldable IOL by one surgeon. Average follow‐up periods were 25±7 months and 23±5 months respectively. There was no difference between the two groups for the follow‐up period (P=0.55), number of post‐operative complications (P=0.25) or cost of post‐operative visits (P=0.83). The cost of single‐use theatre equipment was greater for the rigid‐IOL group (P=0.0001). The total identified cost per patient was greater for the foldable‐IOL group (P=0.0001). Despite possible technical advantages, implantation of the foldable IOL did not provide an economic benefit, either in the initial cost or in the costs of post‐operative care. Over the 2‐year period, implanting with the rigid IOL cost, on average, £57 less per patient. Despite this economic difference, a cost‐benefit analysis is required, since other factors may be more important.
Detection of uveal melanoma by optometrists in the United Kingdom
Authors: Damato Bertil
Published: March 2003

In the United Kingdom, most uveal melanomas are detected by optometrists. Prospectively collected data on patients with uveal melanoma presenting to optometrists were analysed retrospectively to determine: (a) the proportion of patients who were asymptomatic at the time of tumour detection, (b) the proportion of symptomatic patients reporting that their tumour was missed at their initial presentation and (c) the clinical features related to immediate tumour detection. The 223 patients had a mean age of 59.7 years, a mean tumour diameter of 11.3 mm and a mean tumour thickness of 4.6 mm. Symptoms were present in 122 patients (55%) and were associated with large tumour size (p<0.0001) and male gender (p=0.003), with more males tending to have a large tumour (p=0.004). Seventy‐nine percent of symptomatic patients reported that their tumour was detected at their first visit. Failure of tumour detection in symptomatic patients was associated with absence of tumour extension posterior to equator (p<0.0001).
Methods for measuring the proximity‐fixation‐disparity curve
Authors: Jaschinski W.
Published: March 2003

The reliability and validity of new tests of fixation disparity were investigated as a function of viewing distance (100, 60, 40, and 30 cm). The ‘nonius offset card’ presents a set of paired dichoptic nonius (vernier) lines with different offset simultaneously: the subject has to indicate the coinciding lines. The ‘computer test’ uses a psychophysical procedure that presents one pair of nonius lines sequentially with varying offset; the effect of the number of short‐term nonius test trials is investigated. As a reference, the Mallett unit and the Sheedy disparometer were used. Despite different group means, the methods had significant test–retest correlations and inter‐correlations, as tested at 40 cm. All methods showed an increase in exo fixation disparity as the viewing distance was shortened; the slope of this proximity‐fixation‐disparity curve, however, was different between the nonius offset card and the computer test.
MEM and Nott dynamic retinoscopy in patients with disorders of vergence and accommodation
Authors: García Ángel , Cacho Pilar
Published: March 2003

The accommodative response in 34 patients with accommodative and binocular disorders was assessed with two different techniques of dynamic retinoscopy used in clinical practice: monocular estimate method (MEM) and Nott retinoscopy. The data obtained by both techniques were compared, evaluating the correlation and agreement between them. Results showed that there were statistically significant differences between the techniques with MEM values being more plus than Nott ones. There was a high correlation between the two techniques (0.90) and the regression analysis indicated that a linear relationship existed between MEM and Nott dynamic retinoscopy, so that accommodative lag value for Nott dynamic retinoscopy would be calculated by dividing the MEM result by 2. However, although both retinoscopies were related, there was a lack of agreement between them (±0.53 D) indicating that the two methods are not interchangeable for clinical purposes.
Coloured overlays and their effects on reading speed: a review
Authors: Wilkins Arnold
Published: March 2003

Abstract Coloured overlays can reduce symptoms of visual stress and improve reading speed. These benefits are reliable and are not attributable simply to placebo effects. Five percent of children in mainstream education read at least 25% more quickly with an overlay, provided they have chosen the colour. The suboptimal design of children's text and the high level of classroom lighting may be partly responsible.
Transformations of self: a phenomenological investigation into the lived experience of survivors of critical illness
Authors: Papathanassoglou Elizabeth DE , Patiraki Elizabeth I
Published: March 2003

Based on the hermeneutical, phenomenological perspective, this study explored the lived experience of individuals with a past ­hospitalization in an intensive care unit, with focus on their dreams. The purpose was to explore how it is to have been critically ill

Dreams are the language of the unconscious and can symbolically convey meanings

Eight participants recounted their experiences with critical illness through semi‐structured phenomenological interviews and dream‐telling. An interplay between the ‘factual–external’ world and the ‘internal’ world appeared to be the basis of their perception of the situation. Participants’ narratives were immensely rich in symbols of transformation, transcendence and rebirth. Transformations in perception, in lived‐body, and in lived time and space were some of the themes emerging as part of both conscious and dreaming experiences. Attitudes towards death were altered, and elements of heightened spirituality were evident in the aftermath of critical illness

Critical illness was conceptualized as a ‘cocooning phase’ leading to transformation of self, spiritual arousal and personal growth. Nurses may be able to alleviate suffering by supporting this process while in the ICU, as well as after discharge
What Are the Dietary Protein Requirements of Physically Active Individuals? New Evidence on the Effects of Exercise on Protein Utilization During Post‐Exercise Recovery
Authors: Fielding Roger A. , Parkington Jascha
Published: March 2003

Exercise and physical activity increase energy expenditure up to 10‐fold. This brief review will focus on the effect of exercise on protein requirements. Evidence has accumulated that amino acids are oxidized as substrates during prolonged submaximal exercise. In addition, studies have determined that both endurance and resistance training exercise increase skeletal muscle protein synthesis and breakdown in the post‐exercise recovery period. Studies using nitrogen balance have further confirmed that protein requirements for individuals engaged in regular exercise are increased. The current recommended intakes of protein for strength and endurance athletes are 1.6 to 1.7 g/kg and 1.2 to 1.4 g/kg per day, respectively. Presently, most athletes consume an adequate amount of protein in their diet. The timing and nutritional content of the post‐exercise meal, although often overlooked, are known to have synergistic effects on protein accretion after exercise. New evidence suggests that individuals engaging in strenuous activity consume a meal rich in amino acids and carbohydrate soon after the exercise bout or training session.
The Effect of Calcium Consumption on Iron Absorption and Iron Status
Authors: Harris Susan S.
Published: March 2003

Recent increases in recommended calcium intakes recognize the important role of calcium in skeletal health, but many Americans, especially women, consume far less than recommended amounts. A potential drawback to encouraging increased calcium intake is suggested by the extensive literature showing an adverse effect of high calcium intake on dietary iron absorption, at least in short, highly controlled, experimental studies. However, the applicability of short‐term studies involving test meals to long‐term iron absorption and iron status is limited given the variety of foods and food combinations in self‐selected diets and the ability of individuals to adapt to reduced iron intake. In general, studies of whole diets and studies conducted over several weeks tend to show no effect of increased calcium intake on iron absorption. In addition, experimental studies of calcium and iron status measures such as serum ferritin show no long‐term effect of calcium supplementation on iron status. Prevention and treatment of iron deficiency should emphasize adequate consumption of iron‐rich foods and, when indicated, the use of iron supplements. Recommended calcium intakes are important for skeletal health and do not appear to increase the risk for iron deficiency in healthy people.
In vivo characterization of keratinocyte growth factor‐2 as a potential wound healing agent
Authors: Soler Pedro M , Wright Terry E , Smith Paul D , Maggi Sergio P , Hill Donald P , Ko Francis , Jimenez Pablo A , Robson Martin C
Published: March 2003

Human keratinocyte growth factor‐2 exerts a proliferative effect on epithelial cells and mediates keratinocyte migration. It has also been shown to increase both deposition of granulation tissue and collagen and maturation of collagen. Because these properties should affect the healing trajectory of wounds, this study set out to investigate the effects of keratinocyte growth factor‐2 on the healing of three different types of wounds. Human meshed skin grafts explanted to athymic “nude” rats, surgical incisions in Sprague‐Dawley rats, and acute excisional rat wounds inoculated with Escherichia coli were used. Two concentrations of recombinant human keratinocyte growth factor‐2 were compared to a vehicle control and keratinocyte growth factor‐1. Keratinocyte growth factor‐2 significantly accelerated the rate of epithelialization in the meshed skin graft model and effected a modestly more rapid gain in breaking strength of surgical incisions than keratinocyte growth factor‐1 or the vehicle control treatment. Neither keratinocyte growth factors accelerated wound closure by contraction of the excisional wounds. Based on these data, keratinocyte growth factor‐2 may be useful in accelerating healing in wounds healing mainly by the process of epithelialization such as venous stasis ulcers, partial thickness burn wounds, and skin graft donor sites. It might also accelerate the gain in incisional wound strength in acute surgical or traumatic wounds.
Assessment of the potential for microbial resistance to topical use of multiple antimicrobial agents
Authors: Holder Ian A. , Boyce Steven T.
Published: March 2003

The goal of this study was to reduce the likelihood of the generation and/or persistence of bacterial resistance to some antimicrobial components contained in a topical antimicrobial mixture (neomycin, polymyxin B, mupirocin and ciprofloxacin) for use with cultured skin grafts, by substitution of alternative antimicrobials, specifically fusidic acid for mupirocin and ofloxacin for ciprofloxacin. The alternative agents failed to serve that purpose. However, with the exception of specific genera of bacteria, Proteus sp. and Providencia stuartii, 90% or more of all other bacteria tested were susceptible to the action of one or more of the individual antimicrobial agents contained in the original mixture. This was true when bacteria were highly susceptible to the antimicrobials, generally, or when bacteria resistant to specific antimicrobials such as penicillin‐class antibiotics and ciprofloxacin, were tested. These results suggest that the redundancy of antimicrobials contained in this mixture reduces the chance that resistant bacteria generated by the use of this mixture or already present on wounds would persist when the mixture is used clinically.
Matrix remodeling in healing rabbit Achilles tendon
Authors: Reddy G. Kesava , Stehno‐Bittel Lisa , Enwemeka Chukuka S.
Published: March 2003

Biochemical, biomechanical and ultrastructural properties of the connective tissue matrix were investigated during the early remodeling phase of tissue repair in experimentally tenotomized and repaired rabbit Achilles tendons. Sterile surgical tenotomy was performed on the right Achilles tendons of 14 rabbits and allowed to heal for 15 days. The animals were euthanized and the Achilles tendons excised from both limbs. The left contralateral Achilles tendon of each rabbit was used as a control in the experiments. Prior to biochemical analysis, both intact and healing tendons were tested for their biomechanical integrity. The results revealed that the healing tendons had regained some of their physicochemical characteristics, but differed significantly from the intact left tendons. The healing tendons regained 48% tensile strength, 30% energy absorption, 20% tensile stress, and 14% Young’s modulus of elasticity of intact tendons. In contrast, biochemical analysis showed that the healing tendons had 80% of the collagen and 60% of the collagen crosslinks (hydroxypyridinium) of normal tendons. Sequential extraction of collagen from the tissues yielded more soluble collagen in the healing tendons than intact tendons, suggesting either an increase in collagen synthesis and/or enhanced resorption of mature collagen in healing tendons compared to intact tendons. Electron microscopic studies revealed remarkable differences in the ultrastructure between intact and healing tendons. These observations could explain, in part, the connective tissue response to healing during the early phases of tissue remodeling.
Incisional wound healing in transforming growth factor‐β1 null mice
Authors: Koch R. Michael , Roche Nanette S , Parks W. Tony , Ashcroft Gillian S , Letterio John J , Roberts Anita B
Published: March 2003

Expression of endogenous transforming growth factor‐β1 is reduced in many animal models of impaired wound healing, and addition of exogenous transforming growth factor‐β has been shown to improve healing. To test the hypothesis that endogenous transforming growth factor‐β1 is essential for normal wound repair, we have studied wound healing in mice in which the transforming growth factor‐β1 gene has been deleted by homologous recombination. No perceptible differences were observed in wounds made in 3–10‐day‐old neonatal transforming growth factor‐β1 null mice compared to wild‐type littermates. To preclude interference from maternally transferred transforming growth factor‐β1, cutaneous wounds were also made on the backs of 30‐day‐old transforming growth factor‐β1 null and littermate control mice treated with rapamycin, which extends their lifetime and suppresses the inflammatory response characteristic of the transforming growth factor‐β1 null mice. Again, no impairment in healing was seen in transforming growth factor‐β1 null mice. Instead these wounds showed an overall reduction in the amount of granulation tissue and an increased rate of epithelialization compared to littermate controls. Our data suggest that release of transforming growth factor‐β1 from degranulating platelets or secretion by infiltrating macrophages and fibroblasts is not critical to initiation or progression of tissue repair and that endogenous transforming growth factor‐β1 may actually function to increase inflammation and retard wound closure.
Musculoskeletal connective tissue cells with muscle: Expression of muscle actin in and contraction of fibroblasts, chondrocytes, and osteoblasts
Authors: Spector Myron
Published: March 2003

The expression of the gene for a muscle actin in certain nonmuscle cells and the contraction of these connective tissue cells has been associated with several important physiological and pathological processes; the contraction of healing skin wounds and the contracture in Dupuytren's disease being two notable examples. Studies in recent years have shown that a much wider variety of connective tissue cells than previously considered, including cells in many of the musculoskeletal tissues, e.g., chondrocytes and osteoblasts, can express the gene for α‐smooth muscle actin and can display contractile behavior. These findings suggest that muscle actin‐enabled cell contraction may also be playing important roles in the other connective tissues comprising the musculoskeletal system, namely, tendon, ligament, meniscus, intervertebral disc, articular cartilage, and bone.
Debridement performance index and its correlation with complete closure of diabetic foot ulcers
Authors: Saap Liliana J. , Falanga Vincent
Published: March 2003

In recent years there has been wider acceptance of aggressive surgical debridement as a means to accelerate closure of diabetic foot ulcers. In a clinical trial by Steed et al.1 involving the use of a topically applied growth factor, thorough surgical debridement of surrounding callus, necrotic ulcer bed, and undermined ulcers' edges was associated with greater incidence of healing and effectiveness of the therapeutic agent. However, at present there is no established way to judge the appropriate extent of debridement and its performance. Here we describe a scoring system to assess whether debridement has been performed adequately. Our scoring system consists of the following three categories: debridement of a) callus; b) ulcer's edge undermining; and c) wound bed necrotic tissue. We assigned a score of 0–2 to each of these categories using the following criteria: 0 = debridement needed but not done, 1 = debridement needed and done, and 2 = debridement not needed. These three scores are then added to give a total ranging from 0 to 6, with the highest number being the optimal score. This instrument, the Debridement Performance Index, evaluates both the adequacy of debridement and whether the ulcer has been or is being properly debrided. To initiate the validation of this scoring system and determine its predictive value for wound closure by week 12, we applied it to 143 patients with diabetic foot ulcers who had been treated in a clinical trial involving either standard therapy (n = 65) or the application of a bioengineered skin construct (n = 78). We blindly evaluated sequential digital photographs of each diabetic foot ulcer and applied the Debridement Performance Index score at day 0, before initiation of either treatment. We found that the lower the baseline Debridement Performance Index the lower the incidence of ultimate wound closure by week 12 ( p = 0.0276). Patients with a Debridement Performance Index between 3 and 6 were 2.4 times more likely to heal than those with a score of 0–2. After controlling for treatment, the Debridement Performance Index was found to be an independent predictor of wound closure (odds ratio = 2.4 95% confidence interval = 1.0–5.6). In conclusion, this novel scoring system for debridement performance appears to be very promising as a predictive tool for determining outcome in clinical trials and, most likely, in clinical practice. (WOUND REP REG 2002;10:354–359)
Health‐related quality of life and pressure ulceration assessment in patients treated in the community
Authors: Franks Peter J. , Winterberg Hanne , Moffatt Christine J.
Published: March 2003

Little is known of the impact of pressure ulceration on adult patients' health‐related quality of life. The purpose of this study was to determine the impact pressure ulceration has on pressure ulcer patients cared for in the community. A case control study design was used by drawing a random sample from patients receiving community nursing care, stratified by the presence of pressure ulceration. In all, 75 patients with pressure ulcers were compared with 100 controls without ulcers using the four‐point ulcer grading scale described by United Kingdom consensus guidelines. Patients were interviewed using the Short Form‐36 (SF‐36) questionnaire and activities of daily living assessed using the modified Barthel scale. Patients with pressure ulcers had significantly poorer physical function (mean difference [d]=37.6, 95% CI 28.6–46.6, p < 0.001) and social functioning (d=33.9, 95 % CI 24.0–43.9, p < 0.001) than published age‐ and sex‐matched normative data from the United Kingdom. The difference between cases and controls was much smaller in these domains, with neither approaching statistical significance. After adjustment for age and gender, scores for bodily pain were poorer in patients with no ulceration (d=−10.5, 95% CI – 20.6 to – 0.4, p=0.042) indicating greater pain in these patients compared with the cases with ulceration. Activities of daily living determined by the modified Barthel scale showed reduced self‐care (d=−7.6, 95% CI –12.5 to − 2.7, p=0.010) and mobility (d=−9.2, 95% CI −14.6 to − 3.8, p=0.001) in patients with pressure ulceration. The overall ability to perform these activities was also significantly poorer in this group (d=−16.3, 95% CI –27.3 to −5.3, p=0.004).

While patients with pressure ulceration experience some deficits in their health‐related quality of life compared with a normal population, these differences are similar to those experienced by other patients receiving community nursing care. (WOUND REP REG 2002;10:)
Calibration and testing of an empirical chloritoid‐chlorite Mg‐Fe exchange thermometer and thermodynamic data for daphnite
Authors: Vidal  , GoffÉ  , Bousquet  , Parra
Published: March 2003

A compilation of literature data on the Fe‐Mg composition of coexisting chlorite and chloritoid from metapelites metamorphosed at various P‐T  conditions shows that the logarithm of the Fe‐Mg partitioning (lnKD) varies linearly with the inverse of temperature, from about 2.4 at 300 °C to about 1.3 at 600 °C. In contrast, no trend was observed with pressure, and the molar volumes of Mg‐ and Fe‐chlorite end‐members suggest that the pressure dependence of lnKD is not significant. Therefore, the chloritoid‐chlorite Mg‐Fe exchange reaction is a potential thermometer and has been empirically calibrated using the analyses of 112 chloritoid‐chlorite pairs from 28 different localities. Temperatures estimated using the Chl‐Cld thermometer were checked against independent estimates for 20 samples not involved in the calibration (Beni Mzala window, Morocco), and the results are in fair agreement with independent temperature estimates. However, the analytical uncertainties and errors are too large to obtain reliable temperature estimates for extremely Mg‐rich or Fe‐rich compositions. The Chl‐Cld thermometer is unreliable at XMg‐CLD<0.2 and XMg‐CLD>0.8 at 700 °C, and XMg‐CLD<0.1 and XMg‐CLD>0.9 at 300 °C. Using the results of the empirical calibration, we calculated new thermodynamic data for daphnite. Implementing these data, it becomes possible to estimate T  and P conditions of metamorphism for the invariant chlorite‐chloritoid‐quartz‐aluminosilicate assemblage that is widespread in low‐grade metapelites. These estimates appear to be relevant only in the stability field of kyanite, whereas the uncertainties on the calculated pressure conditions are very large in the stability field of kaolinite and pyrophyllite.
The assemblage stilpnomelane–chlorite–phengitic mica: a geothermobarometer for blueschist and associated greenschist terranes
Authors: Currie  , Van Staal
Published: March 2003

Two anhydrous equilibria can be written among the components of stilpnomelane, chlorite, white mica and quartz, namely 89 daphnite+131 Fe‐celadonite+190 quartz=96 stilpnomelane+71 muscovite, and amesite+Mg‐celadonite=muscovite+clinochlore. We assume that the free energy change of reaction, ΔG=ΔGo+ΣRT lnaij, is approximated by ΔG=A−BT +C(P−1)+ΣRT lnaij, where ΔGo is the free energy change of the end‐member components at temperature T  and pressure P, ai is the activity of component i whose coefficient in the equilibrium is j, and A, B and C are constants to be determined. Values of C can be approximated by the change in volume on reaction, namely C=406.517 J/bar for the first reaction and C=0.613 J/bar for the second reaction. Constants A and B were determined by using six occurrences of the assemblage stilpnomelane–chlorite–white mica for which P–T  have been otherwise estimated. Using solution models from the literature, linear regression gives for the first equation A=−6118.269 kJ, B=−4584.09 J/K, and for the second equation A=19.397 kJ, B=66.72 J/K. These values predict P–T  within 0.5 kbar and 25 K for all occurrences, and appear reasonably robust relative to probable analytical errors. P–T  are determined by intersection of the curves generated by given compositions in P–T  space. Fine‐grained and/or zoned chlorite and white mica make application of the geothermobarometer difficult in some instances, but our work in the Bathurst region of New Brunswick suggests that, with patience and care, useful analyses can be obtained, and the database for the geothermobarometer greatly expanded.
Successive hydration and dehydration of high‐P mafic granofels involving clinopyroxene–kyanite symplectites, Mt Daniel, Fiordland, New Zealand
Authors: Daczko N. R. , Stevenson J. A. , Clarke G. L. , Klepeis K. A.
Published: March 2003

Three texturally distinct symplectites occur in mafic granofels of the Arthur River Complex at MtDaniel, Fiordland, New Zealand. These include symplectic intergrowths of clinopyroxene and kyanite, described here for the first time. Pods of mafic granofels occur within the contact aureole of the Early Cretaceous Western Fiordland Orthogneiss batholith. The pods have cores formed entirely of garnet and clinopyroxene, and rims of pseudomorphous coarse‐grained symplectic intergrowths of hornblende and clinozoisite that reflect hydration at moderate to high‐P. These hornfelsic rocks are enveloped by a hornblende–clinozoisite gneissic foliation (S1). Narrow garnet reaction zones, in which hornblende and clinozoisite are replaced by garnet–clinopyroxene assemblages, developed adjacent to fractures and veins that cut S1. Fine‐grained symplectic intergrowths of (1) clinopyroxene and kyanite and (2) clinozoisite, quartz, kyanite and plagioclase form part of the garnet reaction zones and partially replace coarse‐grained S1 hornblende and clinozoisite. The development of the garnet reaction zones and symplectites was promoted by dehydration most probably following cooling of the contact aureole. Maps of oxide weight percent and cation proportions, calculated by performing matrix corrections on maps of X‐ray intensities, are used to study the microstructure of the symplectites.
Reductive deposition of graphite at lithological margins in East Central Vermont: a Sr, C and O isotope study
Authors: Evans K. A. , Bickle M. J. , Skelton A. D. L. , Hall M. , Chapman H.
Published: March 2003

O, Sr and C isotopes from east‐central Vermont are used to provide information on the timing and volume of metamorphic fluid flow. The results are then used to assess the evidence for redox transformations between C species. Oxygen profiles are homogenised on a metre scale; comparison with Sr isotopes suggest that O alteration may have occurred over a significantly larger timescale than that of Sr, possibly because O was modified during dewatering and diagenesis in addition to the high temperature alteration recorded by strontium. Sr isotope distributions are consistent with cross‐layer fluid fluxes of 104−106 moles m−2; absolute values depend on the Sr fluid‐rock distribution coefficient which is poorly known; however, reaction progress constraints suggest that fluxes were towards the lower end of this range. High δ13C values observed at lithological boundaries cannot be explained by volume loss or closed system processes and are taken to indicate reductive precipitation of graphite as a result of mixing between CO2 and CH4‐bearing fluids. Mass balance calculations indicate that redox reactions occurring under metamorphic conditions convert a minimum of 10% of the CO2 released from limestones into graphite, thus providing a potentially important control on the average residence time of C within the crust with implications for C cycling models.
Increasing AV Fistulas: Revisiting a Time‐Tested Solution
Authors: Sands Jeffrey J.
Published: March 2003

Despite having the lowest complication rate of all hemodialysis accesses, the prevalence of autologous arteriovenous (AV) fistulas has declined to 28% in the United States. The reasons for this decline include high early AV fistula failure rates, long maturation times, the frequent need for emergent dialysis, unavailable or poor pre‐ESRD programs and planning, patient resistance to the realities of impending ESRD, and financial disincentives to AV fistula placement. Despite these barriers, programs throughout the country have demonstrated the ability to increase AV fistula prevalence to more than 50%. The strategies employed have included increased reliance on upper arm brachiocephalic and transposed basilic vein fistulas, the use of preoperative imaging to identify the best sites for fistula creation, and aggressive attempts at salvage of nonmaturing fistulas. Other groups have systematically and successfully replaced failed grafts with upper arm brachiocephalic or bracheobasilic fistulas. These experiences clearly show that exceeding the National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF‐DOQI) goal of more than 50% fistula placement is achievable in the United States. Declining numbers of AV fistulas are the result of a combination of factors, including changes in our patient population and learned practice patterns coupled with a failure of our delivery system to provide education, timely referral, and incentives for fistula placement. Increasing AV fistula prevalence in the United States is achievable and will improve patient outcomes and decrease the costs of ESRD.
Preventive Medical Screening Is Not Appropriate for Many Chronic Dialysis Patients
Authors: Holley Jean L.
Published: March 2003

Establishing guidelines for the appropriate preventive medical care for chronic dialysis patients requires consideration of many factors. These include the population's underlying risk factors and expected survival, the effectiveness of screening procedures in improving the duration and/or quality of life, and the potential for renal transplantation. Although many nephrologists order and direct routine cancer screening in their dialysis patients, recent studies suggest such screening is not cost effective. Cardiovascular disease is the leading cause of death among end‐stage renal disease (ESRD) patients and peripheral vascular disease is a leading cause of morbidity among dialysis patients, but even less is known about the cost‐effectiveness of screening for peripheral vascular and cardiovascular disease risks in ESRD patients. Despite a recently reported overall standardized cancer incidence of 1.18 in dialysis patients compared with normal populations, the shortened expected survival of dialysis patients argues against routine cancer screening in this population. Dialysis units and nephrologists should focus cancer screening on individual patients and include specific cancer risk as well as expected survival assessments and transplant candidacy in their decisions to screen a patient for cancer. Routine cancer screening of all dialysis patients is not indicated. Additional study of the benefits and cost‐effectiveness of screening ESRD patients for cardiovascular and peripheral vascular disease risk factors is needed.
A Case for Cellulosic Membrane Hemodialyzers
Authors: Ivanovich Peter , Rosner Karol
Published: March 2003

Regenerated cellulose membranes have been held responsible for a variety of ill effects in dialysis patients. Many of these effects (hypotension, changes in well‐being) have not been supported by studies, while other effects were more likely due to ethylene oxide. The lower cost of dialyzers composed of these membranes may allow implementation of otherwise cost‐prohibitive lifesaving therapy in some countries.
Explaining Counter‐Intuitive Clinical Outcomes Predicted by Kt/V
Authors: Owen William F. , Coladonato Joe , Szczech Lynda , Reddan Donal
Published: March 2003

Population‐based studies of maintenance hemodialysis patients have demonstrated a reproducible relationship between the dose of hemodialysis and mortality and morbidity outcomes. In these analyses, which have aggregated hemodialysis patient subgroups, improved outcomes are associated with greater doses of hemodialysis. However, remarkable counterintuitive findings are observed if patients are analyzed by subgroups based on their race, gender, and anthropometric and blood‐based biomarkers of nutritional state. For example, blacks generally receive lower doses of hemodialysis than whites, but enjoy relatively improved survival; patients who receive the highest doses of hemodialysis have an increased death risk; and the dose response curve between hemodialysis and survival is altered based on the patients' body mass index. These seemingly paradoxical relationships between hemodialysis dose and patient survival can be explained because of the use of mathematical urea kinetic constructs as clinical outcome predictors; they integrate a measure of solute removal (K×t) with an anthropometric surrogate of nutrition, the urea distribution volume (V). Both these measures have an independent influence on patient survival and in some clinical circumstances are of unequal power as clinical outcome predictors. These complex interactions must be kept in perspective as clinical care is delivered in the context of hemodialysis dose.
PTH Metabolites in Renal Failure: Bioactivity and Clinical Implications
Authors: Brossard Jean‐Hugues , Yamamoto Loan Nguyen , D'Amour Pierre
Published: March 2003

Non‐(1‐84) parathyroid hormones (PTHs) are large circulating carboxyl‐terminal PTH (C‐PTH) fragments with a partially preserved amino‐terminal structure. They were discovered during high‐performance liquid chromatography (HPLC) analysis of circulating PTH molecular forms detected by an intact PTH (I‐PTH) assay. Like other C‐PTH fragments, they accumulate in blood in renal failure and account for up to 50% of I‐PTH. They are secreted by the parathyroid glands in humans, and are generated by the peripheral metabolism of hPTH(1‐84) in rats. The exact structure of non‐(1‐84)PTH fragments is not known. To study the possible role of non‐(1‐84) in PTH biology, hPTH(7‐84) has been used as a surrogate, being the only large C fragment available on the market. In anesthetized, thyroparathyroidectomized rats, hPTH(7‐84) caused hypocalcemia beyond that induced by surgery. It also blocked the calcemic response to hPTH(1‐84) or hPTH(1‐34). Other smaller C‐PTH fragments, such as hPTH(39‐84) and hPTH(53‐84), were synergistic to hPTH(7‐84) effects. hPTH(7‐84) did not bind to the PTH/PTHrP receptor, but only to the C‐PTH receptor in ROS 17/2.8 clonal cells, and did not stimulate cyclic adenosine monophosphate (cAMP) production by the same cells, suggesting that its hypocalcemic action was mediated via a receptor different from the PTH/PTHrP receptor, and that the calcium concentration resulted from the sum of the positive effect of hPTH(1‐84) on the PTH/PTHrP receptor and of the negative effect of hPTH(7‐84) and of C‐PTH fragments on the C‐PTH receptor. These data will change our understanding of circulating calcium regulation, which must now be viewed as the end result of opposite actions on two PTH receptors. PTH immunoheterogeneity, a highly regulated phenomenon, contributes to this dual biological effect, generating an agonist for the two different receptors. Clinically these results could have some implications in our knowledge of the PTH resistance of renal failure, of renal osteodystrophy, and of certain aspects of the uremic syndrome.
Automated Peritoneal Dialysis Symposium: The Role of APD in the Improvement of Outcomes in an ESRD Program
Authors: Van Biesen Wim , Veys Nic , Vanholder Raymond , Lameire Norbert
Published: March 2003

We review the role of automated peritoneal dialysis (APD) in improving outcomes of an end‐stage renal disease (ESRD) program. As the “integrated care approach” becomes accepted as the preferred strategy for treatment of ESRD patients, we looked for the potential place of APD in such an approach. APD has probably the same advantages as CAPD as a first‐line renal replacement modality in suitable patients willing to perform PD. There is currently no hard evidence that residual renal function (RRF) should decline more rapidly in APD than in CAPD, at least if a dry abdomen during the day is avoided. The detection of peritonitis is probably more delayed in APD, but the frequency of peritonitis is lower, and there is no hard evidence pointing to a poorer outcome of peritonitis in APD as compared to CAPD. Quality of life is at least as good in APD, which is mostly related to the increased possibilities for adapting the exchange pattern to employment‐related time frames. APD also has the potential to prolong technique success in patients failing CAPD rather than transferring them to hemodialysis. Nevertheless, APD remains more expensive and technically complicated, thereby missing the beauty of CAPD's simplicity. Therefore we believe that APD has its role in an integrated approach and that all patients should be informed of its potential. It would, however, not be correct to present APD as the preferred PD method for all patients, as it also has some drawbacks that make it less suitable for some categories of patients. In all cases, patients should have a free and informed choice.
The Effect of Chronic Renal Failure on Hepatic Drug Metabolism and Drug Disposition
Authors: Dreisbach Albert W. , Lertora Juan J. L.
Published: March 2003

There is abundant evidence that chronic renal failure (CRF) and end‐stage renal disease (ESRD) alter drug disposition by affecting protein and tissue binding and reducing systemic clearance of renally cleared drugs. What is not fully appreciated is that CRF can significantly reduce nonrenal clearance and alter the bioavailability of drugs predominantly metabolized by the liver. Animal studies in CRF have shown a major down‐regulation (40–85%) of hepatic cytochrome P‐450 metabolism involving specific isozymes. Phase II reactions such as acetylation and glucuronidation are also involved, with some isozymes showing induction and others inhibition. Hepatic enzymes exhibiting genetic polymorphisms such as N‐acetyl‐transferase‐2 (NAT‐2), which is responsible for the rapid and slow acetylator phenotypes, have been shown to be inhibited by ESRD and reversed by transplantation. There is some evidence pointing to the possibility of inhibitory factors circulating in the serum in ESRD patients which may be dialyzable. This review includes all significant animal and clinical studies using the search terms “chronic renal failure,”“cytochrome P‐450,” and “liver metabolism” over the past 10 years obtained from the National Library of Medicine MEDLINE database, including relevant articles back to 1969.
HEPARIN‐INDUCED THROMBOCYTOPENIA IN DIALYSIS: The Pathophysiology of Immune‐mediated Heparin‐induced Thrombocytopenia
Authors: Reilly Robert F.
Published: March 2003

Heparin‐induced thrombocytopenia (HIT) is an important side effect of heparin therapy associated with significant morbidity and mortality if unrecognized. The platelet count typically falls below 150,000/µl 5–14 days after heparin is started. Thrombosis is the major clinical complication. The diagnosis is confirmed with a variety of functional and antigenic assays. Heparin binds to PF4, resulting in a conformational change in the molecule that exposes neo‐epitopes that act as immunogens. Antibodies form against the heparin‐PF4 complex, the major target antigen. The IgG‐heparin‐PF4 immune complex binds either via its Fab domain to the platelet surface or via its Fc domain to the FcγIIA receptor on the surface of the platelet, resulting in further platelet activation. Continued release of PF4 from activated platelets leads to increasing PF4‐heparin complex formation, and a self‐propagating cycle of platelet consumption and generation of procoagulant platelet‐derived microparticles. Other procoagulant effects of the HIT antibody include endothelial cell damage, stimulation of platelet‐leukocyte aggregates, and release of tissue factor from monocytes.
Changes in the Work and Motivation of Staff Delivering Home Care Services in Finland
Authors: Laamanen Ritva , Broms Ulla , Häppölä Anja , Brommels Mats ,   Ritva Laamanen is a Lecturer in Health Services Research, Ulla Broms is a Research Associate, Anja Häppölä is a Research Associate, and Mats Brommels is a Professor of Health Services Management in the Department of Public Health, University of Helsinki, Finland.
Published: March 2003

This article describes how the policy to emphasize noninstitutional care is reflected in home care service strategies and work characteristics as well as the work motivation of home care staff in Finland. The data were gathered through a questionnaire answered by 312 employees in home care services and 22 social welfare and primary health care administrators. The methods of analysis used were cross‐tabulations, one‐way analysis of variance, and regression analysis. According to the results, institutional care had been reduced too fast and home care services had not been developed sufficiently. Most of the staff reported that their work had changed considerably. Although their work had become more interesting and more independent, over one third of the employees felt that the pressure of work had become unbearable and their responsibility was too heavy. The views of the home care staff differed from those of the administrators regarding the change strategies that had been carried out. The majority of the staff were moderately or highly motivated. Thirty‐four percent of the variance of work motivation was explained mainly by work characteristics. More attention should be paid to the development of home care services before institutional care is reduced. Training the staff and informing them about the planned reform should not be neglected.
Meanings of Community in a Community Health Center
Authors: Drevdahl Denise
Published: March 2003

As health care organizations make communities the targets for their interventions, connections between “community” as theory for practice and community as setting for practice require examination. This study's purpose was to explore meanings given to community in a newly formed community health center, with particular emphasis on the relationship among women, community, and health. Using interpretive and emancipatory methodologies, interviews were conducted with clinic administrators and staff, and women who used the clinic. Data analysis revealed discrepancies in meanings of community. Clinic personnel referred to community as the target for their services, while clinic users spoke about community as the process that made feeling connected with others possible. Health center staff and administrators described the community they were serving as having limited economic, educational, physical, and psychological resources and saw little which could be labeled a community strength. Health center users however, spoke primarily of their abilities to support each other. These contradictory understandings of the meaning of community rendered different expectations regarding health care services. Meanings given to community may de‐personalize, homogenize, and objectify, and ultimately distance nursing from those intended to be served.