bluuebunny/crossref_metadata_2025 huggingface dataset:
Pediatric Parenteral Nutrition
Authors: Lenders Carine M. , Lo Clifford
Published: March 2003

Abstract Parenteral nutrition has been used with success for the past two decades. In pediatrics, parenteral nutrition has been shown to improve nitrogen balance and growth. However, controversies exist including indications, requirements, duration, outcomes, and costs of parenteral nutrition in the pediatric population. This review provides a brief summary of current indications for pediatric parenteral nutrition and requirements for intravenous nutrients. Guidelines outlined by the American Society for Parenteral and Enteral Nutrition for the pediatric patient are also presented.
Nutrition Support for the Obese Patient
Authors: Shikora Scott A.
Published: March 2003

Abstract The severely obese represent an extremely challenging group of patients. Their body size and associated comorbidities complicate even routine medical care. These management difficulties spill over into nutrition support. As with any patient population, when the severely obese develop conditions such as critical illness and have an interruption in nutritional intake, they deserve aggressive nutrition intervention. However, standard enteral and parenteral approaches may be harmful. Most of the potential adverse effects can be attributed to the concentrated glucose infusion that represents a major calorie source of conventional feeding. To minimize the negative impact of nutrition support, a novel feeding approach, a protein‐sparing, hypocaloric regimen, is presented. This technique preserves protein stores while avoiding glucose‐related complications by intentionally restricting energy administration, in particular, glucose. Although there are relatively few investigations of this nutritional regimen in the literature, those that do exist confirm its safety and suggest a benefit for the patient. This article will review the issues pertaining to standard feeding approaches in the severely obese and the theoretical benefits of hypocaloric nutrition support. It will also review the published studies that used this method.
Benefits of Exercise for Patients with Rheumatoid Arthritis
Authors: Rall Laura C. , Roubenoff Ronenn
Published: March 2003

Rheumatoid arthritis (RA) is a chronic, systemic, autoimmune, inflammatory disorder of unknown etiology and is the most common type of inflammatory arthritis. The disease is most often characterized by morning stiffness, tenderness, and swelling. Other systemic symptoms, such as anemia, increased free radical production, muscle atrophy, and weakness, also occur. Most likely, a combination of these factors contributes to physical inactivity as well, which, in turn, reinforces the muscle wasting. Despite these barriers, it is now becoming recognized that patients with well‐controlled RA can tolerate increased physical activity under carefully supervised conditions and that there are many benefits to exercise. This article reviews the effects of various types of physical activity on RA, with particular emphasis on studies that have examined the use of strength training in clinical practice for the management of RA. Without exception, the studies have shown that increased physical activity in patients with RA improves physical capacity without exacerbating disease activity. Important criteria to consider when recommending an exercise program for patients with RA are outlined.
Plant Stanol/Sterol Ester‐Containing Foods and Cardiovascular Disease Risk
Authors: Lichtenstein Alice H.
Published: March 2003

Cardiovascular disease (CVD) is the leading cause of death and disability in the United States, and an elevated low‐density‐lipoprotein (LDL) cholesterol level is one risk factor. The primary nonpharmacological approach to reducing LDL‐cholesterol levels is to restrict dietary saturated fat and cholesterol. Adjunct strategies are frequently superimposed as well. One newer approach is to substitute foods containing plant sterol/stanol esters for conventional foods such as margarines and salad dressings. Daily consumption of 2–3 g of plant sterol/stanol esters has been reported to reduce LDL‐cholesterol levels by 9% to 20%, with considerable individual variability. This cholesterol lowering appears additive to that achieved with saturated fat and cholesterol restriction or use of hydroxymethylgluteryl‐CoA‐reductase inhibitors. The hypocholesterolemic effect of plant sterol/stanol esters is thought to be mediated primarily by decreasing intestinal cholesterol absorption. Few adverse effects have been reported for short‐ and long‐term use of sterol/stanol ester‐containing foods. However, declines in plasma carotenoids and tocopherol levels have been reported. The clinical significance of this observation is unknown but needs further evaluation. Plant sterol/stanol ester‐containing foods can be used to augment a low‐saturated‐fat and low‐cholesterol diet; however, patients should be cautioned that use beyond the manufacturer‐recommended levels will not result in greater LDL‐cholesterol lowering. If a patient decides to use plant sterol/stanol ester‐containing foods, they should be substituted, not added, to the diet to avoid increasing caloric intake. Additionally, there is no evidence that use of sterol/stanol ester‐containing foods in normocholesterolemic individuals will prevent the onset of elevated cholesterol levels.
Including Nutrition in an Ambulatory Care Path for Patients with Type 2 Diabetes
Authors: Peery Annette , Darrow Mark , Hardee Sandra , Kolasa Kathryn M.
Published: March 2003

Care paths are known to improve the performance of health care providers in delivering diabetes education. This paper describes the efforts of a rural family practice to implement a provider‐and patient‐focused care path for the improved management of Type 2 diabetes. Dietary and lifestyle advice were included elements in the care path. Family physicians with limited access to dietetic services need to provide more diet and lifestyle advice than other physicians. Patient‐focused care paths are expected to enhance provider‐patient communication and improve patient adherence.
Preventive Nutrition and Physical Activity: An Exercise in Interviewing for Medical Students
Authors: Ross Elizabeth M.
Published: March 2003

Preventive care guidelines for physicians recommend patient counseling to promote a healthy diet and regular physical activity. Unfortunately, there is a paucity of materials to support training in these skills for medical students. This assignment is intended to help medical students learn to integrate questions about preventive nutrition and physical activity into the standard medical history, and then to synthesize the information they gather into a coherent assessment and plan using evidence‐based national guidelines.
Nutrition and Oral Precancerous Lesions
Authors: Mayne Susan Taylor , Morse Douglas E.
Published: March 2003

Oral precancerous lesions include oral leukoplakia, erythroplakia, and erythroleukoplakia. These lesions are of interest clinically because they can progress into oral carcinomas and therefore denote individuals who are at increased risk for oral carcinomas. Oral precancerous lesions are also of interest as intermediate endpoints for intervention trials, in order to screen agents that might have efficacy in oral cancer chemoprevention. While tobacco and alcohol reduction and/or cessation are clearly the most important strategies for reducing the risk of oral precancerous lesions and oral cancers, evidence also supports a possible role for nutrition in the etiology and management of both conditions. Observational epidemiologic studies indicate that lower consumption of fruits and vegetables is associated with an increased risk of oral precancerous lesions, a finding consistent with associations seen for oral cancers. Chemoprevention studies have evaluated the effects of supplemental nutrients (eg, β‐carotene; vitamins A, C, and E; selenium) on oral leukoplakia and oral dysplasia. Supplemental β‐carotene, in particular, has documented efficacy in the regression of oral precancerous lesions. However, supplemental β‐carotene may not be advisable in this patient population due to concerns about a possible increase in lung cancer risk. Retinoids also have documented efficacy in the regression of oral precancerous lesions, but retinoids can have considerable side effects, and long‐term efficacy in the prevention of oral cancer is unknown. Given these findings, encouraging increased fruit and vegetable intake for the prevention and management of oral precancerous lesions is prudent; all other nutritional approaches for these conditions remain investigational.
Stress and Distress in Clinical Practice: A Mind‐Body Approach
Authors: Selhub Eva M.
Published: March 2003

Primary care physicians are often taxed by patient complaints that do not seem to have a clear etiology, nor do the patients improve despite good medications and expensive procedures. Current studies show that stress or distress may have a significant effect on the onset, the course, and the management of many, if not all, diseases. Understanding patient's underlying stress physiology and coping mechanisms may enable physicians to better understand various clinical disorders and treat their manifested symptoms. Evidence is reviewed by which stress may exacerbate or cause illness and by which behavioral medicine interventions can improve clinical outcomes.
Differential expression of hepatocyte growth factor and its receptor (c‐Met) in a rat artificial anus model
Authors: Lu Yue Ping , Nishigai Keiko , Ishiwata Toshiyuki , Asano Goro
Published: March 2003

Hepatocyte growth factor is a multifunctional polypeptide that has been implicated in cancer growth, tissue development and wound repair. It is mainly synthesized in mesenchymal cells and acts on epithelial cells, where its actions are dependent on binding to a specific cell‐surface hepatocyte growth factor receptor (c‐Met). In an artificial anus, two different types of epithelial cells (ductal cells of the colon and squamous cells of the skin) intermingle with each other. In the present study, we examined the localization of hepatocyte growth factor and c‐Met during the process of repair in a rat artificial anus model, and attempted to clarify the cell types that express hepatocyte growth factor or c‐Met messenger RNA by in situ hybridization. Western blot analysis revealed abundant localization of the mature form of hepatocyte growth factor in artificial anal tissues. Moderate hepatocyte growth factor immunoreactivity was noted in regenerated squamous cells in the skin and colonic ductal cells, and strong expression in macrophages and fibroblasts. Moderate c‐Met immunoreactivity was present in regenerated epithelial cells in the skin and colon. Throughout the repair process, hepatocyte growth factor and c‐Met immunoreactivities were more prominently localized in the squamous cells of the skin than in colonic ductal cells. Competitive reverse transcription‐polymerase chain reaction analysis revealed that hepatocyte growth factor mRNA was maximal on day 14 after the operation; however, c‐Met mRNA expression had two peaks, on day 1 and day 7. Hepatocyte growth factor mRNA was expressed more in the stromal fibroblasts, macrophages and endothelial cells, and c‐Met mRNA was predominant in regenerated squamous cells of the skin. These findings suggest the possibility that hepatocyte growth factor may act in a paracrine manner to mainly enhance the growth of squamous cells of the skin and to a lesser extent the ductal cells of the colon in the artificial anus.
Success and limitations of a naked plasmid transfection protocol for keratinocyte growth factor‐1 to enhance cutaneous wound healing
Authors: Byrnes Colman K , Khan Faisal H , Nass Petra H , Hatoum Chehada , Duncan Mark D , Harmon John W
Published: March 2003

Our group and others have previously reported enhancement of cutaneous wound healing following the transfection of tissue with plasmid vectors expressing the DNA for growth factors. In these experiments, growth factor treated animals were usually compared to animals treated with control plasmid vector. To achieve consistent transfection, high DNA plasmid load and repeated penetrations of the wound by needle or gene gun were required. In the current experiments, we assessed the effect of the plasmid load and repeated tissue penetrations on wound healing of excisional wounds in diabetic C57 mice. Animals received 5 mm excisional wounds, and were assigned to the following groups, no treatment, phosphate buffered saline solution injections, and plasmid vector injection with and without the keratinocyte growth factor‐1 gene. Intradermal injections of 100μg plasmid were given adjacent to the wounds at days 1–5, 7 and 11. At day 9, wound closure was more advanced in keratinocyte growth factor‐1 treated animals compared to those treated with control plasmid. But a detrimental effect of the DNA plasmid injection was evident from a comparison of the DNA control group versus the non‐injected group. Therefore, the challenge for developing an effective system for the enhancement of wound healing lies in improving transfection efficiency.
Expression of preadipocyte factor‐1(Pref‐1), a delta‐like protein, in healing mouse ears
Authors: Samulewicz Stefan Jude , Seitz Alexander , Clark Lise , Heber‐Katz Ellen
Published: March 2003

Preadipocyte factor‐1 (Pref‐1), a delta‐like protein containing epidermal growth factor‐repeats, is expressed in proliferating cells in a variety of tissues and is believed to be involved in maintaining the undifferentiated state of these cells. Using microarray analysis, reverse transcriptase‐polymerase chain reaction, in‐situ hybridization, and immunohistochemistry, we have identified Pref‐1 expression in the healing ears of two strains of mice, MRL and C57BL/6. MRL is unusual in that ear punches completely regenerate the ear tissue along with new cartilage with no scarring. Pref‐1 is more highly expressed in the MRL wounds, is uniquely found in a condensation of cells within the regenerating tissue of the blastema, and may contribute to the regenerative capacity of the MRL ear wound. (WOUND REP REG 2002;10:215–221)
Morphologic examination of CD3–CD4bright cells in rat liver
Authors: Yamamoto Satoshi , Sato Yosinobu , Abo Toru , Hatakeyama Katsuyosi
Published: March 2003

Recently, we found CD3−CD4bright cells with comparative specificity for normal rat liver. In the current study, we investigated the type and form of both CD3–CD4bright cells and CD3–CD4dull cells in the rat liver. The surface phenotype of hepatic mononuclear cells in Lewis rats was identified by using monoclonal antibodies including anti‐CD4, anti‐CD3, and antimacrophage in conjunction with two‐ or three‐color immunofluorescence analysis. CD3–CD4bright cells and CD3–CD4dull cells were examined morphologically using May‐Giemsa staining and scanning electron microscopy. The distribution of CD3–CD4bright cells and CD3–CD4dull cells 48 hours after intravenous administration of liposome‐encapsulated dichloromethylene diphosphate was also investigated. In comparison to CD3–CD4dull cells, CD3–CD4bright cells were slightly larger macrophages with abundant cytoplasmic granules, being present with comparative specificity for normal rat liver and showing negligible effects by intravenous liposome‐encapsulated dichloromethylene diphosphate administration. These data suggest that in normal young rat liver these CD3–CD4dull and CD3–CD4bright cells may be dendritic cells and Kupffer cells that shift from the liver to the spleen or vice versa. These cells may also be able to locally proliferate in liver or spleen due to changes in the developing liver. (WOUND REP REG 2002;10:241–244)
Protective effect of a novel NO‐donor on ischemia/reperfusion injury in a rat epigastric flap model
Authors: Mittermayr Rainer , Valentini Daniela , Fitzal Florian , Hallström Seth , Gasser Harald , Redl Heinz
Published: March 2003

An altered metabolism of endothelial cell–derived nitric oxide has been implicated in the microvascular dysfunction associated with ischemia/reperfusion. The objective of this study was to examine whether S‐nitroso human serum albumin, a novel nitric oxide‐donor, improves flap viability and whether it influences edema formation after prolonged ischemia when administered prior to and in the initial phase of reperfusion. Denervated epigastric island skin flaps were elevated in 30 male Sprague Dawley rats, rendered ischemic for 8 hours, subsequently reperfused and further observed for either 3 hours (acute) or 7 days (chronic). In the sham rats (n = 6), skin flaps were elevated only. Starting 1 hour prior to reperfusion, S‐nitroso human serum albumin (n = 12) or human serum albumin (n = 12) as placebo was infused systemically for 2 hours. In the chronic model, flap necrosis as well as viable flap size was evaluated after 7 days of reperfusion in six rats per group, comparing to sham rats. In the acute model, edema formation was evaluated after 3 hours of reperfusion in six rats per group. Administration of S‐nitroso human serum albumin significantly decreased flap necrosis from 18.1 ± 15.6% in the human serum albumin group to 2.1 ± 1.5% in the S‐nitroso human serum albumin group, which was similar to the sham group (2.5 ± 4.2%). Viable flap size (sham 13.4 ± 1.6 cm2) was also significantly improved in the S‐nitroso human serum albumin group (10.1 ± 1 cm2) versus the human serum albumin group (7.0 ± 2.2 cm2). There was no significant difference between the groups regarding postischemic edema formation. These results show that administration of S‐nitroso human serum albumin prior to and in the initial phase of reperfusion significantly improves flap viability after 7 days but does not influence early observable edema formation. These findings support the role of nitric oxide as an important mediator in the protection against skin flap ischemia/reperfusion injury. (WOUND REP REG 2003;11:3–10)
Approaches to equilibrium in the distribution of trace elements among the principal minerals in a high‐grade metamorphic terrane
Authors: Kretz  , Campbell  , Hoffman  , Hartree  , Teesdale
Published: March 2003

X‐ray fluorescence, instrumental neutron activation, and particle‐induced X‐ray emission methods were used to determine the distribution of numerous trace elements among garnet (Grt), Ca‐pyroxene (Cpx), hornblende (Hbl), biotite (Bt), plagioclase (Pl) and K‐feldspar (Kf) in a high‐grade metamorphic terrane within the Grenville Province of the Canadian Shield. Results are presented as distribution formulae, e.g.

Sr: Kf 1.1 Pl 16 Hbl 2.2 Cpx 1.0 Bt 1.2 Grt

Sc: Hbl 1.1 Cpx 1.0 Grt 7.8 Bt 22 Pl 2.6 Kf

V: Hbl 1.15 Bt 2.07 Cpx 6.0 Grt (1.4% CaO)>1 (Pl, Kf)

Zn: Bt 1.6 Hbl 1.62 Cpx 2.9 Grt 10 Pl

Ga: Bt 1.2 Hbl 1.2 Pl 2.5 Cpx 1.3 Grt

where numbers are distribution ratios, e.g. ppm Sr in Hbl/ppm Sr in Cpx=2.2. Examples of inter‐element similarities and differences are (a) both Rb and Cs are concentrated in biotite relative to K‐feldspar, but for Rb the ratio is 2.3 and for Cs it is 16, (b) the distribution formulae for seven lanthanides are similar except for the position of garnet, e.g.

Ce: Hbl 2.7 Cpx 2.8 Pl 1.1 Bt 11 Kf 16 Grt

Yb: Grt 2.8 Hbl 2.7 Cpx 9 Pl 1.0 Bt 7 Kf

and (c) all of Sr, eight lanthanides, Zr, V and Cr are concentrated in hornblende relative to Ca‐pyroxene by a factor that lies in the narrow range of 2.2–3.1. There is a larger variation (departure from the mean) in some distribution ratios than in others. Thus the mean ratios (Hbl/Cpx) for each of six elements and in parentheses the percentage relative standard deviation are Zn 1.62 (8.6), V 2.38 (12), Cr 2.42 (18), Sr 2.7 (28), Ba 2.9 (36) and Ni 1.66 (38). We suggest that variation of this kind is the result of differences from place to place in the magnitude of deformation and recrystallization (which facilitated the rearrangement of atoms), combined with rates of lattice and crystal‐boundary diffusion that are unique for the various elements, thus permitting some trace elements to approach equilibrium more closely than others.
Eclogites in the Makuti gneisses of Zimbabwe: implications for the tectonic evolution of the Zambezi Belt in southern Africa
Authors: Dirks  , Sithole
Published: March 2003

The gneisses of the Makuti Group in north‐west Zimbabwe are characterized by complex geometries that resulted from intense non‐coaxial deformation in a crustal scale high‐strain zone that accommodated extensional deformation along the axis of the Zambezi Belt at c. 800 Ma. Within low‐strain domains in the Makuti gneisses, undeformed metagabbroic lenses preserve eclogite and granulite facies assemblages, which record a part of the metamorphic history that predates Pan‐African events. Eclogitic rocks can be subdivided into: (1) corona‐textured metagabbros that preserve igneous textures, and (2) garnet–omphacite rocks in which primary textures are destroyed. The lenses of eclogitic rocks are enveloped in a mantle of garnet–clinopyroxene–hornblende gneiss, which is a common rock type in the Makuti gneisses. The eclogites preserve multi‐staged, domainal, symplectic reaction textures that developed progressively as the rocks experienced loading followed by decompression–heating. In the metagabbros, the original clinopyroxene, plagioclase and olivine domains acted separately during the peak of metamorphism, with plagioclase being replaced by garnet and kyanite, and olivine being replaced by orthopyroxene and possibly omphacite. The peak assemblage was overprinted by: (1) the multi‐mineralic corona assemblage pargasite–orthopyroxene–spinel–plagioclase replacing garnet–kyanite–clinopyroxene (possibly at c. 19 kbar, 760±25 °C); (2) orthopyroxene–pargasite–plagioclase–scapolite coronas replacing orthopyroxene (15±1.5 kbar, 750±50 °C); and (3) moats of orthopyroxene–plagioclase replacing garnet (10±1 kbar, 760±50 °C). The garnet–omphacite rocks record similar peak conditions (15±1.1 kbar, 760±60 °C). Garnet–clinopyroxene–hornblende–plagioclase gneisses envelop the eclogites and record matrix conditions of 11±1.5 kbar at 730±50 °C using assemblages that are oriented in the regional fabric. These rocks are characterized by decompression‐heating textures, reflecting temperature increases during exhumation of the Makuti gneisses.

The eclogite facies rocks formed during a collisional event prior to 850 Ma. Their formation could be related to a suture zone that developed along the axis of the Zambezi Belt during the formation of Rodinia (between 1400 and 850 Ma). The main deformation‐metamorphism in the Makuti gneisses occurred around 800 Ma and involved extension and exhumation of the high‐P rocks (break‐up of Rodinia), which experienced a high‐T metamorphic overprint. Around 550–500 Ma, a collisional event associated with the formation of Gondwana resulted in renewed burial and metamorphic recrystallization of the Makuti gneisses.
Deformation, high‐pressure metamorphism and exhumation of ultramafic rocks in a deep subduction/collision setting (Cabo Ortegal, NW Spain)
Authors: Gil Ibarguchi  , Ábalos  , Azcarraga  , Puelles
Published: March 2003

New petrological and microstructural data from various metaperidotite ‘boudins’ within large ductile shear zones in the Cabo Ortegal allochthonous complex in NW Spain have important implications for the tectonic models of the area. The peridotites (mylonitic garnet harzburgite, Ti‐clinohumite and magnesite–olivine orthopyroxenite) contain mineral assemblages that equilibrated at high‐ to ultra‐high‐pressure metamorphic conditions as well as microstructures of tectonic origin formed at temperatures well above 800 °C. Olivine and orthopyroxene fabrics resulted from flow at high temperature (>1000 °C) and solid‐state non‐coaxial plastic flow at intermediate temperature (800–900 °C). Flow caused dynamic recrystallization and formation of moderate to strong lattice preferred orientations under low to moderate differential stresses and strain rates characteristic of upper mantle and deep crustal deformation. The microstructures and textural relationships suggest that the mylonitic garnet harzburgite represents mantle fragments with lithospheric and asthenospheric imprints, whereas the olivine orthopyroxenite resulted from serpentinite burial to depths where it acquired a characteristic high/ultra‐high‐pressure metamorphic signature. Both types of ultramafites converged to a common site in a subduction zone that was later incorporated during continental collision to the NW Iberian Massif as exotic, allochthonous complexes that record structural and metamorphic evidence of the earliest phases of the Hercynian orogeny.
Evolution of high‐Mg–Al granulites from Sunkarametta, Eastern Ghats, India: evidence for a lower crustal heating–cooling trajectory
Authors: Bose,  , Fukuoka,  , Sengupta,  , Dasgupta,
Published: March 2003

A suite of high‐Mg–Al granulites from Sunkarametta, Eastern Ghats Belt, India, shows contrasting prograde assemblages of extremely aluminous orthopyroxene+cordierite+sapphirine and similarly aluminous orthopyroxene+Ti‐rich spinel in closely associated domains. Textural and compositional characteristics indicate that both were derived from prograde dehydration–melting of biotite–plagioclase–quartz‐bearing protoliths. The former assemblage was stabilized at relatively more magnesian bulk composition. Geothermobarometric data and petrogenetic grid considerations place ‘peak’ metamorphic conditions at c. 950 °C and 9 kbar. Subsequent to peak metamorphism, the rocks cooled to c. 700–750 °C, with slight lowering of pressure, and the retrograde reactions also involved melt–solid interaction. The inferred P–T  trajectory is one of heating–cooling at lower crustal (25–30 km) depths.
P–T evolution of glaucophane–omphacite bearing HP–LT rocks in the western Tianshan Orogen, NW China:new evidence for ‘Alpine‐type’ tectonics
Authors: Klemd R. , Schröter F. C. , Will T. M. , Gao J.
Published: March 2003

The late Palaeozoic western Tianshan high‐pressure /low‐temperature belt extends for about 200 km along the south‐central Tianshan suture zone and is composed mainly of blueschist, eclogite and epidote amphibolite/greenschist facies rocks. P–T conditions of mafic garnet omphacite and garnet–omphacite blueschist, which are interlayered with eclogite, were investigated in order to establish an exhumation path for these high‐pressure rocks. Maximum pressure conditions are represented by the assemblage garnet–omphacite–paragonite–phengite–glaucophane–quartz–rutile. Estimated maximum pressures range between 18 and 21 kbar at temperatures between 490 and 570 °C. Decompression caused the destabilization of omphacite, garnet and glaucophane to albite, Ca‐amphibole and chlorite. The post‐eclogite facies metamorphic conditions between 9 and 14 kbar at 480–570 °C suggest an almost isothermal decompression from eclogite to epidote–amphibolite facies conditions. Prograde growth zoning and mineral inclusions in garnet as well as post‐eclogite facies conditions are evidence for a clockwise P–T path. Analysis of phase diagrams constrains the P–T path to more or less isothermal cooling which is well corroborated by the results of geothermobarometry and mineral textures. This implies that the high‐pressure rocks from the western Tianshan Orogen formed in a tectonic regime similar to ‘Alpine‐type’ tectonics. This contradicts previous models which favour ‘Franciscan‐type’ tectonics for the southern Tianshan high‐pressure rocks.
Blueschist facies metamorphism of peralkaline rhyolites from the Tenda crystalline massif (northern Corsica): evidence for involvement in the Alpine subduction event?
Authors: Tribuzio R. , Giacomini F.
Published: March 2003

The Tenda crystalline massif (northern Corsica) is a fragment of the western Corsica basement involved in the Alpine orogeny. Rhyolite dykes crosscutting the gabbroic complex of Bocca di Tenda (southern sector of the Tenda crystalline massif) show an unusual metamorphic mineral assemblage, defined by jadeite‐bearing (up to 46 mol percentage) aegirine, riebeckite, celadonite‐rich phengite (Si=3.50–3.65 apfu), quartz, albite and K‐feldspar. Jadeite‐bearing aegirine and riebeckite mostly occur as coronas around jadeite‐free aegirine and arfvedsonite, respectively, which both are relics of igneous origin. This metamorphic assemblage reflects the peralkaline compositions, which are characterised by anomalously high contents of SiO2 and Na2O, and negligible CaO and MgO. The evolved rocks of the gabbroic sequence (quartz‐diorites to tonalites) and the surrounding granitoids are characterised by the development of riebeckite/ferroglaucophane, epidote, celadonite‐rich phengite and albite, thus pointing to a metamorphic crystallization in the epidote‐blueschist facies. In all the studied rocks, metamorphic reactions were controlled by fluid‐assisted mass‐transfer through grain boundaries and microfractures. The different mineral assemblages allow the peak P–T metamorphic conditions to be constrained to between 0.8 GPa/300 °C and 1.1 GPa/500 °C. These estimates attest to a geothermal gradient (dT/dP) of 10–13 °C km−1 and indicate that the Tenda crystalline massif was buried to a minimum depth of 27 km during the Alpine orogeny. The blueschist facies recrystallization in the Tenda crystalline massif has been related to the cessation of an eastward‐dipping subduction event.
ACID‐BASE IN RENAL FAILURE: Disturbances of Acid‐Base Balance and Bone Disease in End‐Stage Renal Disease
Authors: Kraut Jeffrey A.
Published: March 2003

Bone disease in patients with chronic renal failure (CRF) is thought to be the consequence primarily of the interplay of several factors, including the serum levels of parathyroid hormone (PTH), vitamin D, calcium, and phosphorus, and exposure to bone toxins such as aluminum or amyloid. Recently the metabolic acidosis noted with CRF has been implicated as an additional factor contributing to the genesis of bone disease. Although metabolic acidosis might be the dominant factor in the cause of bone disease in some instances, more commonly this acid‐base disturbance interacts with other factors contributing to the development of bone disease. The following article summarizes the data in support of an important role for metabolic acidosis in the genesis of bone disease in patients with CRF and presents our recommendations for treatment of uremic acidosis to prevent or treat the bone disease.
Ultrapure Dialysate: A Desirable and Achievable Goal for Routine Hemodialysis
Authors: Ward Richard A.
Published: March 2003

United States standards for the microbiologic quality of dialysate are not very stringent and have remained unchanged for more than 20 years, despite significant changes in the patient population and in the technology of hemodialysis. Numerous studies have demonstrated that bacterial products can cross dialysis membranes and stimulate an inflammatory response in the patient. Inflammation has been implicated in several complications associated with long‐term hemodialysis therapy, and the use of ultrapure dialysate has been shown to reduce the incidence of one of these complications, β2‐microglobulin amyloidosis. Since technological innovations in water treatment and improvements in dialysis machine design allow the routine production of ultrapure dialysate, its use should now become standard.
Serum Albumin: Its Significance in Patients with ESRD
Authors: Steinman Theodore I.
Published: March 2003

Hypoalbuminemia is a major risk factor for morbidity and mortality in the ESRD population. The Core Indicators Project notes that the serum albumin value is a measure of the patient's nutritional status. Since 1994 every outcome parameter of the Core Indicators Project has shown improvement except for the serum albumin measurement. While the serum albumin level is a measure of the visceral protein pool size, a decrease in albumin synthesis is due to more than poor nutritional intake (in part related to inadequate dialysis). Acute‐phase reactants and the plasma volume status are other major factors that impact on serum albumin determination. Plasma volume expansion, albumin redistribution, exogenous loss (in peritoneal dialysis patients), and decreased albumin synthesis all contribute to hypoalbuminemia. Understanding the cause (s) of hypoalbuminemia will allow us to target treatment modalities directed at correcting the hypoalbuminemia. It is still unknown if the serum albumin can be effectively raised in the chronic dialysis patient. Also unknown is whether an increase in the serum albumin level can alter long‐term morbidity and mortality. We should not be using serum albumin as an indicator of adequate dialysis or nutritional status since the causes of hypoalbuminemia are multifactorial. It is recommended that the serum albumin level be eliminated as an indicator of nutritional status in the ESRD patient.
Reconciling Differences in Effective Solute Removal Between Intermittent and Continuous Therapies
Authors: Clark William R. , Ronco Claudio
Published: March 2003

Solute removal by various forms of renal replacement therapy (RRT) differs from that occurring in the native kidney in several ways. Among the dialytic therapies, the relationship between clearance and mass removal rate may differ substantially. The purpose of this article is to review the various approaches that have been proposed to account for this differing relationship among the various types of RRT. Specific quantitative approaches along with clinical applications are provided.
Uremic Toxicity: Urea and Beyond
Authors: Depner Thomas A.
Published: March 2003

Successful replacement of renal function with dialysis supports the concept that uremia is a toxic state resulting from accumulated solutes and that toxicity results from high concentrations of these solutes in body fluids. Dialyzer clearance of urea, a surrogate toxin, is the currently accepted best measure of dialysis and dialysis adequacy, but it is admittedly a compromise due to current lack of knowledge about and inability to measure more toxic solutes. This failure could be explained if uremic toxicity is actually a summation effect of multiple toxins, each at individual subtoxic levels in the patient. Other solutes could be used as surrogates to measure clearance, but urea happens to be available in high concentrations, is easily measured by all clinical laboratories, and is easily dialyzed, so changes in concentration are sensitive indicators of clearance. Measurements of creatinine clearance are confounded by the disequilibrium that occurs across red cells within the dialyzer and in the patient. Other solutes probably behave more like creatinine than urea, so urea stands out as uniquely diffusible, a property that actually spoils its effectiveness as a surrogate toxin, especially when applied to more frequent and continuous dialysis. Accumulation of other solutes may correlate better with toxic uremic symptoms and the residual syndrome. More studies are needed to examine the kinetics of other solutes, their generation rates, and their distribution volumes to provide clinicians with more knowledge and tools to optimize dialysis treatments. Examination of the effectiveness of solute removal in patients dialyzed more frequently may provide significant insight into the pathogenesis of uremia.
Temperature and Thermal Balance in Hemodialysis
Authors: Schneditz Daniel
Published: March 2003

The analysis of thermal balance and temperature in hemodialysis patients reveals both striking similarities and important differences to urea kinetics. Both urea and thermal energy need to be removed during hemodialysis, however, for different reasons. Urea accumulates between hemodialysis treatments, whereas thermal energy accumulates within hemodialysis treatments. Urea concentration is ideally reduced by approximately 70% during a treatment, whereas temperature is ideally kept constant by removing up to 50% of resting energy expenditure because heat dissipation from the body surface is obstructed as a result of ultrafiltration‐induced hypovolemia. Extracorporeal heat removal is controlled by several factors. Dialysate and patient temperatures play the main role. Low body temperatures are not uncommon with hemodialysis patients, so that dialysate temperatures less than 36°C are often required to maintain reasonable temperature gradients. Another important role is played by extracorporeal blood flow. At the same temperature gradient, heat transfer by extracorporeal blood flow used with high‐efficiency dialysis is approximately six times more efficient than the dissipation of heat across the body surface. And, last but not least, the venous section of the extracorporeal circulation provides constant cooling of approximately 10 W. Almost all dialysis treatments provide extracorporeal cooling, even those using dialysate at 37°C. Therefore it is probably better to define the thermal aspects of hemodialysis with regard to the physiologic effects on the patient. Since thermoregulation responds to changes in body temperature, treatments should be characterized as isothermic, hypothermic, and hyperthermic.
Chronic Catheter Placement
Authors: Work Jack
Published: March 2003

Since the 1997 publication of the Disease Outcomes Quality Initiative (DOQI) vascular access guidelines for cuffed, tunneled catheter placement, additional evidence supporting these recommendations has been published, including additional documentation supporting the right internal jugular vein as the preferred site for insertion. Placing the catheter tip in the right atrium rather than in the superior vena cava will provide adequate blood flow to support effective hemodialysis. The right atrial positioning of the catheter tip will also accommodate catheter tip retraction and decrease the likelihood of malfunction. Overwhelming evidence now supports the use of ultrasound guidance to assist cannulation of the internal jugular vein. This evidence is based on several studies documenting anatomical variations of the internal jugular vein. Ultrasound guidance has significantly decreased the incidence of serious complications of jugular vein cannulation. Finally, a specific technique of catheter placement with variations for catheter types is described.
ESRD in the Geriatric Population: The Crisis of Managed Care and the Opportunity of Disease Management
Authors: Steinman Theodore I.
Published: March 2003

The geriatric population with end‐stage renal disease (ESRD) is placed at risk with regards to the quality and extent of medical coverage because of the rapidly changing financial environment. Managed care organizations (MCOs) are generally for‐profit companies that must focus on the bottom line. While the verbal commitment to quality care is voiced, the financial pressures on MCOs have led to a decrease in coverage of many services and outright denial for some necessary treatments. While denying services, the MCOs have also reduced payments to providers for services rendered. The coverage crisis is compounded by health maintenance organizations (HMOs) quitting Medicare because the reimbursement from the Health Care Financing Administration (HCFA) is less than their costs. Because of the above issues which can potentially impact on the quality of care delivered to the ESRD geriatric population, a new approach to disease management has created the opportunity to improve total patient care to a level not yet achieved in the United States. Disease management encompasses integrated care across all disciplines. Every component of care can be tracked by a dedicated information system. Improvement in outcomes has far exceeded the U.S. Renal Data System (USRDS) benchmark performance measurements with a disease management model approach. The key to success is the health service coordinator (HSC), a senior nurse with many years of ESRD experience. This individual coordinates care across all disciplines and expedites necessary referrals. With rapid attention to patient needs there has been a significant reduction in hospital admissions, hospital length of stay, and emergency room visits. Patient care will steadily improve as the disease management system matures as a consequence of understanding the patients total physical and psychosocial needs.
Chronic Peritoneal Dialysis in the Elderly
Authors: Dimkovic Nada , Oreopoulos Dimitrios G.
Published: March 2003

Available data indicate that peritoneal dialysis (PD) offers some advantages for the increasing number of elderly patients with ESRD, such as hemodynamic stability, steady‐state metabolic control, good control of hypertension, independence from hospital visits, and avoidance of repeated vascular access. Early referral promotes the establishment of peritoneal access and minimizes the consequences of uremia and subsequent morbidity and frequent hospitalization. Elderly patients have similar modality‐related complications such as peritonitis, catheter‐related complications, exit‐site and tunnel infection, and hernias as younger patients. Comorbid conditions, malnutrition, and psychosocial status influence the survival of elderly patients on PD. Elderly patients are compliant and highly motivated to cooperate in treatment. They are more tolerant of changes and losses and have a greater sense of well‐being, less illness and modality‐related stress, and fewer mood disturbances. Despite comorbid conditions, that significantly impair self‐performance of dialysis, PD can be performed successfully if they have family support or access to a network of medical and social support, that is, home nurses, rehabilitation services, and chronic care dialysis units, or nursing homes.
Automated Peritoneal Dialysis Symposium: Solutions for APD: Special Considerations
Authors: Passlick‐Deetjen J. , Schaub T. P. , Schilling H.
Published: March 2003

Automated peritoneal dialysis (APD) has become the fastest growing dialysis modality in Europe and the United States in recent years. Freedom from daytime exchanges, flexibility of prescription, performance in recumbent position leading to enhanced treatment efficacy, and a decreased incidence of peritonitis are the main advantages of APD over CAPD. Studies on new developments of glucose‐based PD fluids were performed predominantly in CAPD patients. High volumes and frequent APD cycles in patients may aggravate the adverse effects of standard CAPD fluids on the peritoneal membrane with increasing time on PD. New, glucose‐based PD fluids with neutral pH, very low concentrations of glucose degradation products (GDPs), containing either lactate or bicarbonate as buffering substances have been introduced into clinical use recently. With these new fluids, various in vitro, ex vivo, and in vivo studies could demonstrate a better preservation of peritoneal cell viability and growth, less inhibited secretory cell functions, a significant reduction in the formation of advanced glycation end products (AGEs), and clinical signs for an improved preservation of peritoneal mesothelial cells indicated by an increase in effluent CA125. One has to be aware, however, that uremia per se prior to initiation of PD, as well as during PD treatment itself, directly impacts on peritoneal membrane structural changes so that new, more biocompatible PD fluids may not be completely sufficient to prevent morphologic and functional changes of the membrane. Due to a strong sodium sieving during APD, PD fluids with sodium concentrations of 125–130 mmol/L may be beneficial. Systematic calcium kinetic studies have not yet been performed in APD patients. APD fluids should offer a calcium concentration range of 1.0–1.75 mmol/L in order to enable an individualized APD prescription. For long‐term APD treatment, better knowledge of peritoneal membrane physiology and PD kinetics should promote individualization of prescriptions. New, pH‐neutral PD solutions with minimized amounts of GDPs may be a significant step forward to improved membrane preservation during long‐term APD treatment.
Effect of Ageing on Morphologic and Clinical Predictors of Prostate Cancer Progression
Authors: Stamey Thomas A. , Raimondo Marc , Yemoto Cheryl M. , McNeal John E. , Johnstone Iain M.
Published: March 2003

Objectives: Autopsy studies show that prostate cancer begins in the 4th and 5th decade of life. We sought to determine if increasing age at the time of diagnosis is related to morphologic and clinical predictors of cancer progression.

Materials and Methods: We examined 7 morphologic variables known to impact progression of prostate cancer plus clinical stage and serum PSA in relation to increasing age. 981 untreated men undergoing radical prostatectomy were divided into 5 increasing age groups. Prostate size, which is known to increase with age, was used as a positive control. We compared the median and inter‐quartile range for each grouping.

Results: Increase in prostate weight was highly significant at all age differences. The % Gleason grade 4/5 cancer and cancer volume showed the most statistically significant changes with ageing, followed by non‐organ confined cancer and capsular penetration both of which are highly correlated with cancer volume. Serum PSA was significant at 12, 17, and 22 years of age differences, but may be related more to prostate size than to increasing cancer volume. The presence of positive lymph nodes, seminal vesicle invasion, and palpable cancer were unrelated to increasing age.

Conclusions: With the exception of increasing prostate size, % Gleason grade 4/5 cancer and cancer volume are the most significantly related variables to increasing age. Since % Gleason grade 4/5 cancer and cancer volume are also the primary determinants of failure to cure prostate cancer by radical prostatectomy, these age related changes suggest that detection of prostate cancer later in life will be accompanied by increased amounts of high grade cancer and larger tumor volumes. They also explain why, in so many younger men (age 45–60), the largest prostate cancer is often clinically insignificant (< 0.5 cc) at the time of radical prostatectomy.
Serum Prostate Specific Antigen as a Predictor of Survival in Prostate Cancer Patients Treated with Second‐Line Hormonal Therapy (CALGB 9181)
Authors: Halabi Susan , Conaway Mark R. , Small Eric J. , Vogelzang Nicholas J. , Dawson Nancy A.
Published: March 2003

Objectives: To explore whether serum prostate specific antigen (PSA) decline can be used as a prognostic factor for survival among patients with androgen‐independent prostate cancer (AIPC) who are treated with a secondary hormonal therapy, megestrol acetate.

Materials and Methods: One hundred forty‐nine patients were randomized with equal probability to either low‐dose (160 mg/day) or high‐dose (640 mg/day) megestrol acetate. Patients were stratified on performance status (0–1, or 2) and on disease measurability (measurable, or evaluable disease).

Results: Patients with high pretreatment PSA (≥95 ng/ml) had worse survival times than patients with low PSA (<95), with a hazard ratio of 1.6 (p = 0.003). The median survival times for patients with a ≥50% reduction in PSA at 8 weeks and those patients without a 50% reduction were 15 and 11 months, respectively (p = 0.763). A landmark analysis at 8 weeks showed that a PSA decline was significantly associated with survival. The survival time for patients whose PSA dropped below the pretreatment levels (median = 15 months) were significantly longer than for patients who did not have a decline in PSA (median = 9 months, p = 0.031). Similar significant results were observed between PSA reduction and survival when landmark analyses were performed at 12 and 16 weeks. PSA changes during the first 45 days after the initiation of therapy were significantly related to survival. The median survival time for patients whose PSA doubled during the first 45 days after treatment and for patients whose PSA did not double during the first 45 days were 10 and 14 months, respectively (p = 0.020).

Conclusions: PSA decline is significantly associated with longer survival times in prostate patients treated with secondary hormonal manipulation. Longer survival time is observed among the following AIPC patients: 1) those whose pretreatment PSA were <95 ng/ml: 2) those whose PSA decline was >0% from baseline; and 3) those whose PSA did not double during the first 45 days of therapy. If these observations are generalizeable, PSA decline as a criterion of response could be used to rapidly approve new agents in patients treated with second‐line hormonal therapy.