bluuebunny/crossref_metadata_2025 huggingface dataset:
Matrix metalloproteinase production in regenerating axolotl spinal cord
Authors: Chernoff Ellen A. G. , O'hara Christina M. , Bauerle Debra , Bowling Michael
Published: March 2003

In urodele amphibian spinal cord regeneration, the ependymal cells lining the central canal remodel the lesion site to favor axonal regrowth. We profiled the production of matrix metalloproteinases by injury‐reactive mesenchymal ependymal cells in vivo and in vitro and found that matrix metalloproteinases are involved in this remodeling process in the axolotl (Ambystoma mexicanum). The production of cell‐associated matrix metalloproteinases in vivo was shown to be identical to that in our cultured ependymal cell model system. Activated and zymogen forms of matrix metalloproteinases were identified using zymography, chemical inhibitors of matrix metalloproteinases, and cleavage of propeptides by organomercurials. The principal cellular proteinases consisted of matrix metalloproteinase‐2 (gelatinase A) and matrix metalloproteinase‐1 (type I collagenase), which display characteristic shifts in molecular weight following proenzyme processing by organomercurials. In addition, ependymal cell conditioned medium contained secreted forms of the enzyme undetectable in situ. Matrix metalloproteinase‐9 (gelatinase B) as well as matrix metalloproteinase‐2 and matrix metalloproteinase‐1 were secreted and casein substrate zymography showed the presence of a small amount of a very high molecular weight matrix metalloproteinase‐3 (prostromelysin) secreted into the culture medium. Matrix metalloproteinases were still present at 4 weeks post‐lesioning when the ependymal cells have just re‐epithelialized, but decreased near the completion of regeneration (8 weeks post‐lesioning). Zymography showed no detectable matrix metalloproteinases in unlesioned cord but the presence of tissue inhibitor of metalloproteinase‐1 in intact cord was seen by Western blotting. This study shows that matrix metalloproteinases are associated with urodele spinal cord regeneration and validates the use of our ependymal cell tissue culture model system to evaluate ependymal cell behavior during spinal cord regeneration.
Phenotypic variation in the production of bioactive hepatocyte growth factor/scatter factor by oral mucosal and skin fibroblasts
Authors: Stephens Phil , Hiscox Steve , Cook Helen , Jiang Wen G , Zhiquiang Wu , Thomas David W
Published: March 2003

Hepatocyte growth factor/scatter factor (HGF/SF) is a pleiotropic growth factor produced principally by cells of mesenchymal origin. HGF/SF is an important mitogen, morphogen, and motogen and plays an important role in wound healing, tumorigenesis and particularly fetal development. Oral mucosal fibroblasts exhibit a fetal phenotype, including an increased extracellular matrix reorganizational ability, cellular migration and experimental wound repopulation in comparison to skin fibroblasts. In this study the expression, production, and bioactivity of HGF/SF by oral mucosal and skin fibroblasts was investigated. Although both oral mucosal and skin fibroblasts expressed HGF/SF, the oral mucosal fibroblasts produced significantly increased amounts of total HGF/SF (p < 0.01) as measured by enzyme‐linked immunosorbent assay and bioactive HGF/SF as measured by cell scatter and cell‐dissociation techniques (p < 0.01). The possible effect of increased HGF/SF in production mediating the previously described preferential responses of oral mucosal fibroblasts was studied in vitro. Reverse transcriptase‐polymerase chain reaction–Western blotting and immunocytochemistry methods all showed that both oral mucosal and skin fibroblasts expressed and produced the c‐Met receptor. Recombinant HGF (20–40 ng/mL) however, failed to affect fibroblast repopulation of monolayer wounds or cellular proliferation. In contrast, recombinant HGF significantly increased ECV304 wound repopulation. These studies provide direct evidence of another mechanism by which site‐specific variations in fibroblast phenotype may contribute in a paracrine fashion to the rapid reepithelialization and revascularization of oral wounds.
Modified cotton gauze dressings that selectively absorb neutrophil elastase activity in solution
Authors: Edwards J. Vincent , Yager Dorne R , Cohen I. Kelman , Diegelmann Robert F , Montante Steven , Bertoniere Noelie , Bopp Alvin F
Published: March 2003

Dressings for chronic human wounds have been aimed at protection, removal of exudate, and improved appearance. However since the time of ancient Greece wound care and dressing strategies have primarily relied on empiricism. Recent studies have shown that chronic wounds contain high levels of tissue and cytokine destroying proteases including collagenase and neutrophil elastase. Therefore we sought to develop an effective wound dressing that could absorb elastase through affinity sequestration. Cotton gauze was modified by oxidation, phosphorylation, and sulfonation to enhance elastase affinity by ionic or active site uptake. Type VII absorbent cotton gauze was oxidized to dialdehyde cotton which was subsequently converted in part to the bisulfite addition product. Gauze preparations were also phosphorylated and carboxymethylated. Modified cotton gauzes were compared with untreated gauze for reduction of elastase activity in buffered saline. Solutions of elastase that were soaked in oxidized, sulfonated, and phosphorylated cotton gauze showed reduced elastase activity. The initial velocities (vo) and turnover rates of elastase showed significant decreases compared with solutions taken from untreated gauze. The reduction in enzyme activity with dialdehyde cotton gauze was confirmed in solution by determining elastase inhibition with dialdehyde starch. The dialdehyde cotton gauze also decreased elastase activity in human wound fluid in a dose response relation based on weight of gauze per volume of wound fluid. Absorbency, pH, air permeability and strength properties of the modified gauze were also compared with untreated cotton gauze. This report shows the effect of reducing elastase activity in solution with cotton containing aldehydic or negatively charged cellulose fibers that may be applicable to treatment modalities in chronic wounds.
Laser photostimulation accelerates wound healing in diabetic rats
Authors: Reddy G. Kesava , Stehno‐Bittel Lisa , Enwemeka Chukuka S.
Published: March 2003

In this study, we examined the hypothesis that laser photostimulation can facilitate healing of impaired wounds in experimental diabetes using a rat model. Diabetes was induced in male rats by streptozotocin injection and two 6 mm diameter circular wounds were created on either side of the spine. The left wound of each animal was treated with a 632.8nm He:Ne laser at a dose of 1.0J/cm2 for five days a week until the wounds closed (three weeks). Measurements of the biomechanical properties of the laser‐treated wounds indicated there was a marginal increase in maximum load (16%), stress (16%), strain (27%), energy absorption (47%) and toughness (84%) compared to control wounds of diabetic rats. Biochemical assays revealed that the amount of total collagen was significantly increased in laser treated wounds (274 ± 8.7 μg) over the control wounds (230 ± 8.4 μg). Sequential extractions of collagen from healing wounds showed that laser treated wounds had significantly greater concentrations of neutral salt soluble (15%) and insoluble collagen (16%) than control wounds, suggesting accelerated collagen production in laser treated wounds. There was an appreciable decrease in pepsin soluble collagen (19%) in laser treated wounds over control wounds, indicating higher resistance to proteolytic digestion. In conclusion, the biomechanical and biochemical results collectively suggest that laser photostimulation promotes the tissue repair process by accelerating collagen production and promoting overall connective tissue stability in healing wounds of diabetic rats.
Use of molecular techniques to study microbial diversity in the skin: Chronic wounds reevaluated
Authors: Davies Charlotte E , Wilson Melanie J , Hill Katja E , Stephens Phil , Hill C. Michael , Harding Keith G , Thomas David W
Published: March 2003

The skin is colonized by an array of microorganisms which form its natural microflora. Disruption to the normal barrier function of the skin (due to trauma or disease) may result in invasion of the dermis by opportunistic bacteria. To date, these organisms, which may contribute to the chronicity of skin wounds, have been analyzed solely by culture methods. It is increasingly realized that standard culture methods of analysis do not accurately reflect the full diversity of complex microflora. This review discusses the limitations of traditional culture approaches and reviews recent advances in molecular microbiological techniques which facilitate a more comprehensive characterization of the microflora within clinical samples. The currently available technologies and techniques are described, as is their use in clinical practice and their potential for diagnostic screening. Chronic venous ulceration of the lower limbs is an important skin disorder in which the microflora invading the dermal tissues contribute to the observed delayed healing. Using chronic leg ulcers as a working example, we show how strict culture and molecular microbiological techniques may be employed, for the first time in combination, to definitively characterize the invading microbial community of the dermis.
Appearance of leptin in wound fluid as a response to injury
Authors: Marikovsky Moshe , Rosenblum Charles I. , Faltin Zehava , Friedman‐Einat Miriam
Published: March 2003

The adiposity hormone leptin regulates food intake, body weight, reproduction and other metabolic and endocrine functions mainly through signaling to the hypothalamus. Leptin signaling to peripheral tissues other than the hypothalamus has been suggested for a number of processes such as immunity, bone metabolism, hematopoiesis, angiogenesis, and wound healing. It was previously shown that exogenously applied leptin accelerated wound healing and that leptin mRNA is expressed at the wound site, but there is no published evidence showing that it is translated into leptin protein that is available at the site of repair. To address this question we analyzed pig wound fluids collected from partial‐thickness excisional wounds during the first 9 days after injury. Leptin was measured using a modified culture of HEK‐293 cells, expressing both the human leptin receptor gene and the firefly luciferase gene driven by a STAT‐inducible promoter. Relatively high levels of leptin activity (50–250 ng/ml) were detected in wound fluids using the leptin receptor expressing HEK‐293 cells. Our results suggest that leptin is normally induced (4.8‐ to 10.2‐fold) in wound tissue during the first few days following injury and may operate in a paracrine or autocrine circuit during the wound repair process. (WOUND REP REG 2002;10:302–307)
Changes in serum levels of apolipoprotein A‐1 as an indicator of protein metabolism after hepatectomy
Authors: KATSURAMAKI TADASHI , HIRATA KOICHI , KIMURA YASUTOSHI , NAGAYAMA MINORU , MEGURO MAKOTO , KIMURA HITOSHI , HONMA TOSHIO , FURUHATA TOMOHISA , HIDEKI URA , HATA FUMITAKE , MUKAIYA MITSUHIRO
Published: March 2003

The clinical significance of serum apolipoprotein A‐1 levels as an indicator of hepatic protein synthesis after hepatectomy was investigated. A total of 50 patients who had undergone hepatectomy at our department from 1997 to 1999 were selected for this study. The serum levels of apolipoprotein A‐1, indocyanine green dye retention at 15 minutes, lectin‐cholesterol acyltransferase, prealbumin, and high‐density lipoprotein cholesterol were measured in these patients preoperatively and on postoperative days 7 and 14. The type of hepatic resection conducted was partial resection in 13 cases, subsegmentectomy in 13 cases, segmentectomy in five cases, and bisegmentectomy in 19 cases. All the patients tolerated the operation, and none of the cases had any severe complications, such as liver failure. In most cases, the serum apolipoprotein A‐1 levels decreased on postoperative day 7 and recovered by day 14. There were no significant differences in the changes in apolipoprotein A‐1 levels between patients with the individual types of operative procedures. The serum apolipoprotein A‐1 levels showed significant correlations with the serum high‐density lipoprotein cholesterol, lectin‐cholesterol acyltransferase and prealbumin levels on postoperative days 7 and 14; however, there was no significant correlation with the indocyanine green retention test. When the cases were divided into three groups according to the serum level of apolipoprotein A‐1 on postoperative day 7 (group A: over 81 mg/dl, group B: 61–80 mg/dl, group C: under 60 mg/dl), the serum indocyanine green retention, prealbumin, lectin‐cholesterol acyltransferase and high‐density lipoprotein cholesterol levels in group C were significantly lower than those in group A on postoperative day 7. On the basis of these results, it is suggested that the pattern of changes in the serum apolipoprotein A‐1 levels may be a good indicator of the hepatic protein synthetic ability during the perioperative period after hepatectomy.
Evidence for sequential utilization of fibronectin, vitronectin, and collagen during fibroblast‐mediated collagen contraction
Authors: Sethi Kamaljit K. , Yannas Ioannis V. , Mudera Vivek , Eastwood Mark , McFarland Clive , Brown Robert A.
Published: March 2003

Contraction plays a major role in wound healing and is inevitably mediated through the mechanical interaction of fibroblast cytoskeleton and integrins with their extracellular matrix ligands. Cell–matrix attachment is critical for such events. In human dermal fibroblasts most such interactions are mediated by the β1‐type integrins. This study investigated the role played by key components in this system, notably fibronectin, vitronectin, and integrin subcomponents α2 and α5, which recognize collagen and fibronectin. Inhibition of adhesion through these ligands was studied either by antibody blocking or with fibronectin and/or vitronectin depletion. Functional effects of inhibition were monitored as force generation in collagen‐glycosaminoglycan (IntegraTM) sponges, over 20 hours using a culture force monitor. Dose and time‐course inhibition studies indicated that initial attachment and force generation (approx. 0–5 hours postseeding) was through fibronectin receptors and this was followed by vitronectin ligand and receptor utilization (4 hours onward). Utilization of the collagen integrin subcomponent α2 appeared to be increasingly important between 6 and 16 hours and dominant thereafter. Additionally, there was evidence for functional interdependence between the three ligand systems fibronectin, vitronectin, and collagen. We propose that there is a short cascade of sequential integrin–ligand interactions as cells attach to, extend through, and eventually contract their matrix. (WOUND REP REG 2002;10:–408)
Deep subduction of mantle‐derived garnet peridotites from the Su‐Lu UHP metamorphic terrane in China
Authors: Yang  , Jahn
Published: March 2003

Garnet peridotites from the southern Su‐Lu ultra‐high‐pressure metamorphic (UHPM) terrane, eastern China, contain porphyroblastic garnet with aligned inclusions comprising a low‐P–T  mineral assemblage (chlorite, hornblende, Na‐gedrite, Na‐phlogopite, talc, spinel and pyrite). Orthopyroxene porphyroblasts show fine exsolution lamellae of clinopyroxene and minor chromite. A clinopyroxene inclusion in garnet shows some orthopyroxene exsolution lamellae. Both the rims of porphyroblastic pyroxene and garnet and the matrix pyroxene and garnet crystallized at the expense of olivine. This is interpreted as a result of metasomatism of the peridotites by an SiO2‐rich melt at UHP conditions. A chromian garnet further overgrew on the rims of the garnet. The XMg values (Mg/(Mg+Fe)) of porphyroblastic garnet decrease from core to rim and vary in different peridotite samples, while the compositions of both the porphyroblastic and the matrix pyroxene are similar in terms of Ca–Mg–Fe. The Mg‐rich cores of porphyroblastic garnet and orthopyroxene record high temperatures and pressures (c. 1000 °C, ≥5.1 GPa), whereas the matrix minerals, including the rims of porphyroblasts, record much lower P–T  (c. 4.2 GPa, c. 760 °C). Sm–Nd data give apparent isochron ages of c. 380 Ma and negative εNd(0) values (c.−9). These dates are considered meaningless due to isotopic disequilibrium between garnet cores and the rest of the rocks. The isotopic disequilibrium was probably caused by metasomatism of the peridotites by melt/fluids derived from the coevally subducted crustal materials. On the other hand, the Rb–Sr isotopic systems of phlogopite and clinopyroxene appear to have reached equilibrium and record a cooling age of c. 205 Ma. It is suggested that the garnet peridotites were originally emplaced into a low‐P–T  environment prior to the c. 220 Ma continental collision, during which they were subducted together with crustal rocks to mantle depth and subjected to UHP metamorphism. An important corollary is that at least some of the coevally subducted crustal rocks in the Su‐Lu terrane have been subjected to peak metamorphism at P–T  conditions much higher than presently estimated (≥2.7 GPa, ≤800 °C).
Timing and rate of isothermal decompression in Pan‐African granulites from Rundvågshetta, East Antarctica
Authors: Fraser G. , McDougall I. , Ellis D. J. , Williams I. S.
Published: March 2003

Geochronological data, combined with field and petrological evidence, constrain the timing and rate of near‐isothermal decompression at granulite facies temperatures in rocks from the Lützow‐Holm Complex of East Antarctica. Granulite facies gneisses from Rundvågshetta in Lützow‐Holm Bay experienced a peak metamorphic temperature of over 900 °C at c. 11 kbar, as evidenced by primary orthopyroxene–sillimanite‐bearing assemblages, and secondary cordierite–sapphirine‐bearing assemblages in metapelites. Peak metamorphic assemblages show strong preferred mineral orientation, interpreted to have developed synchronously with pervasive ductile deformation. Zircon from a syndeformational leucosome has a U–Pb age of 517±9 Ma, which is interpreted as a melt crystallization age. This age provides the best estimate of the time of peak metamorphic conditions. The post‐peak metamorphic history is characterized by near‐isothermal decompression, recorded by mineral textures in a variety of rock compositions. Field and textural relations indicate that decompression post‐dated pervasive ductile deformation. K/Ar and 40Ar/39Ar ages from hornblende and biotite represent closure ages during cooling subsequent to decompression, and indicate cooling to temperatures between c. 350 and 300 °C by c. 500 Ma, thus placing a lower time limit on the duration of the high‐temperature isothermal decompression episode. The combination of the zircon age from a syndeformational melt with K/Ar and 40Ar/39Ar closure ages indicates that near‐isothermal decompression from c. 11 to c. 4 kbar at granulite facies temperatures, followed by cooling to c. 300 °C, took place within a time interval of 20±10 Myr. Simple one‐dimensional models for exhumation‐controlled cooling indicate that these data require exhumation rates of the order of c. 3 km Myr−1 for several million years, then cessation of exhumation followed by relatively isobaric cooling during thermal re‐equilibration.
Hornblende geothermometry of amphibolite layers of the Popple Hill gneiss, north‐west Adirondack Lowlands, New York, USA
Authors: Liogys  , Jenkins
Published: March 2003

The exchange reaction tschermakite+2 diopside+2 quartz=tremolite+2 anorthite (HPCQ), in combination with the thermodynamic database TWQ (version 1.02, Berman, 1991), has been evaluated for its usefulness as a geothermometer. This reaction, which is both water conserving (independent of water fugacity) and which does not require the presence of garnet, is well suited for studying pyroxene‐bearing amphibolites. As an application of this geothermometer, we have re‐examined the amphibolites occurring in the Popple Hill gneiss of the Adirondack Lowlands of New York, USA, to better understand the magnitude of temperature variation preserved in the amphibolites themselves in this classic locality. At an assumed constant pressure of 7 kbar, the temperatures range from 619 to 682 °C from Edwards to Pierrepont and are uncorrelated with either distance along the strike of the region or with modal mineralogical variations. Hornblende exhibits a narrow compositional range suggesting that there has been little or no thermal gradient along the strike of the Lowlands. Temperatures recorded just north of Colton are, however, distinctly higher (694–758 °C). Although it is likely that the Popple Hill gneiss amphibolites experienced some effects of progressive metamorphism, particularly in the vicinity of Colton, the variations in modal mineralogy are most likely the result of such factors as local variations in the bulk chemistry of the protolith and in the fugacity of H2O due to infiltration of diluting species (e.g. CO2, CH4), rather than a regional temperature variation. Temperatures recorded by the HPCQ geothermometer reported here are similar in magnitude and geographic trend to those reported for graphite–calcite carbon‐isotope thermometry by Kitchen & Valley (1995), suggesting that peak metamorphism in the Adirondack Lowlands involved laterally extensive and fairly uniform isotherms.
A re‐evaluation of eclogite facies metamorphism in SW Japan: proposal for an eclogite nappe
Authors: Wallis S. , Aoya M.
Published: March 2003

Known eclogite occurrences in the Sanbagawa metamorphic belt of SW Japan are dominantly in metagabbro bodies which have complex polyphase metamorphic histories. These bodies are generally described as tectonic blocks and their relationship to the Sanbagawa metamorphism is unclear. New findings of foliated eclogite in the Seba and Kotsu areas show that eclogite facies metamorphism is much more widespread than generally thought. Evidence that the foliated eclogite units originated as lavas or sediments implies that these units can be treated as a high‐grade part of the subduction‐related Sanbagawa metamorphism. Although separated by an along‐strike distance of 80 km, the Seba and Kotsu eclogites have very similar garnet and omphacite compositions, suggesting that they were formed under similar metamorphic conditions. However, differences in the associated retrograde assemblages (epidote–amphibolite in the Seba unit and epidote–blueschist in the Kotsu unit) suggest contrasting P–T  paths. In both units, the eclogite rocks occupy the highest structural level of the Sanbagawa belt and overlie rocks metamorphosed at lower pressure. The lower boundary to the eclogite units is therefore a major tectonic discontinuity locally decorated with lenses of exotic material. These features can help trace the boundary into other areas. The previously known outcrops of eclogite show enough similarities with the newly found areas to suggest that all the eclogite facies rocks in the Sanbagawa belt constitute a single nappe that lies at the highest structural levels of the orogen.
Silica precipitates in omphacite from eclogite at Alpe Arami, Switzerland: evidence of deep subduction
Authors: Dobrzhinetskaya L. F. , Schweinehage R. , Massonne H.‐J. , Green H. W.
Published: March 2003

Observations of oriented SiO2 precipitates in omphacite from eclogite with tholeiitic basalt protolith bordering the Alpe Arami garnet peridotite massif, Ticino, Switzerland, and petrological studies of the eclogitic mineral assemblages, suggest that this rock was subjected to higher‐pressure metamorphism than previously realized. We employed various calibrations of the Fe2+ − Mg exchange thermometer and calculations of equilibria with thermodynamic data, considering the calcium–Tschermak's component (CaAl2SiO6), of garnet‐pyroxene pairs. From these calculations, it is concluded that the eclogitic lenses have recorded at least four stages of mineral growth corresponding to the following: Stage I (prograde) c. 2.4 GPa; 700 °C; Stage IIa (maximum recorded grade) c. 7.0 GPa; 1100 °C; Stage IIb (retrograde) c. 3.7 GPa; 900 °C; Stage III (retrograde) c. 2.1 GPa; 750 °C. Because of the preservation of Stage I, a relatively rapid subduction and exhumation of Alpe Arami eclogite is suggested. The exhumation path of the eclogitic rock is in good agreement with most exhumation paths inferred for the Alpe Arami garnet lherzolite proposed previously by several authors based upon a variety of different observations, although the eclogite and peridotite exhumation paths may diverge at depths greater than 120 km.
The formation of eclogite facies metatroctolites and a general petrogenetic grid in Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O (NCFMASH)
Authors: Rebay G. , Powell R.
Published: March 2003

Eclogite facies metatroctolites from a variety of Western Alps localities (Voltri, Monviso, Lanzo, Allalin, Zermat–Saas, etc.) that preserve textural evidence of their original form as bimineralic olivine‐plagioclase rocks are considered in terms of calculated mineral equilibria in the system Na2O‐CaO‐FeO‐MgO‐Al2O3‐SiO2‐H2O (NCFMASH). Pseudosections, based on a new petrogenetic grid for NCFMASH presented here, are used to unravel the metamorphic history of the metatroctolites, considering the rocks to consist of different composition microdomains corresponding to the original olivine and plagioclase grains. On the basis that the preservation of the mineral assemblage in each microdomain will tend to be from where on a rock's P–T path the metamorphic fluid phase is used up via rehydration reactions, P–T pseudosections contoured for water content, and P–T path‐MH2O (amount of water) pseudosections, are used to examine fluid behaviour in each microdomain. We show that the different microdomains are likely to preserve their mineral assemblages from different places on the P–T path. For the olivine microdomain, the diagnostic mineral assemblage is chloritoid + talc (+ garnet + omphacite). The preservation of this assemblage, in the light of the closed system P–T path‐MH2O relationships, implies that the microdomain loses its metamorphic fluid as it starts to decompress, and, in the absence of subsequent hydration, the high pressure mineral assemblage is then preserved. In the plagioclase microdomain, the diagnostic assemblage is epidote (or zoisite) + kyanite + quartz suggesting a lower pressure (of about 2 GPa) than for the olivine microdomain. In the light of P–T path‐MH2O relationships, development of this assemblage implies breakdown of lawsonite across the lawsonite breakdown reaction, regardless of the maximum pressure reached. It is likely that the plagioclase microdomain was mainly fluid‐absent prior to lawsonite breakdown, only becoming fluid‐present across the reaction, then immediately becoming fluid‐absent again.
Metamorphic textures and P–T evolution of high‐P granulites from the Lelukuau terrane, NE Grenville Province
Authors: Indares A. D.
Published: March 2003

High‐pressure (HP) granulites and eclogitized metagabbro are exposed along an orogen‐parallel high‐P belt that was developed at c. 1050–1020 Ma in the NE Grenville Province. Among these rocks, mafic granulites derived from a Labradorian anorthosite suite of the Lelukuau terrane contain garnet, Al‐Na diopside, and, depending on bulk composition, plagioclase and kyanite. Moreover, the distribution of phases is influenced by the original igneous texture. For instance, in high XMgO leucocratic varieties, garnet porphyroblasts nucleated together with kyanite in An‐rich cores of plagioclase domains whereas in low XMgO rocks garnet occurs together with clinopyroxene within formerly igneous ferromagnesian domains and kyanite is missing. In contrast, garnet pseudomorphs after igneous plagioclase in melanocratic varieties display evidence of earlier corona development.

 Metamorphic textures are consistent with a two stage evolution: (a) development of garnet and Al‐Na‐diopside (Cpx1) under high‐P metamorphic conditions, concomitant with elimination of plagioclase in the mesocratic to melanocratic varieties; and (b) partial loss of Al‐Na from Cpx1 resulting in production of new andesitic plagioclase, and growth of new clinopyroxene (Cpx2) after garnet and quartz in leucocratic to mesocratic rocks consistent with decompression. Widespread equilibrium textures between garnet‐Pl2‐Cpx2 and/or reset Cpx1 are consistent with development at the thermal peak. Estimated P–T conditions for the presumed thermal peak fall in the range 1500–1800 MPa and 800–900 °C and are comparable to those recorded by eclogitized gabbros from other parts of the high‐P belt of the NE Grenville province.

 Low jadeite content of clinopyroxene from the HP granulites is attributed to the low bulk Na2O/(Na2O + CaO) of these rocks relative to common basaltic compositions. Scarcity of apparent retrograde textural overprint in both the HP granulites and the eclogites suggests fast subsequent cooling, consistent with extrusion of the high‐P belt towards the foreland shortly after the metamorphic peak.
Deep in the Heart of Dixie: Pre‐Alleghanian Eclogite and HP Granulite Metamorphism in the Carolina Terrane, South Carolina, USA
Authors: Shervais J. W. , Dennis A. J. , Mcgee J. J. , Secor D.
Published: March 2003

The central part of the Carolina terrane in western South Carolina comprises a 30 to 40 km wide zone of high grade gneisses that are distinct from greenschist facies metavolcanic rocks of the Carolina slate belt (to the SE) and amphibolite facies metavolcanic and metaplutonic rocks of the Charlotte belt (to the NW). This region, termed the Silverstreet domain, is characterized by penetratively deformed felsic gneisses, granitic gneisses, and amphibolites. Mineral assemblages and textures suggest that these rocks formed under high‐pressure metamorphic conditions, ranging from eclogite facies through high‐P granulite to upper amphibolite facies.

Mafic rocks occur as amphibolite dykes, as metre‐scale blocks of coarse‐grained garnet‐clinopyroxene amphibolite in felsic gneiss, and as residual boulders in deeply weathered felsic gneiss. Inferred omphacite has been replaced by a vermicular symplectite of sodic plagioclase in diopside, consistent with decompression at moderate to high temperatures and a change from eclogite to granulite facies conditions. All samples have been partially or wholly retrograded to amphibolite assemblages. We infer the following P‐T‐t history: (1) eclogite facies P‐T conditions at ≥ 1.4 GPa, 650–730 °C (2) high‐P granulite facies P‐T conditions at 1.2–1.5 GPa, 700–800 °C (3) retrograde amphibolite facies P‐T conditions at 0.9–1.2 GPa and 720–660 °C. This metamorphic evolution must predate intrusion of the 415 Ma Newberry granite and must postdate formation of the Charlotte belt and Slate belt arcs (620 to 550 Ma).

Comparison with other medium temperature eclogites and high pressure granulites suggests that these assemblages are most likely to form during collisional orogenesis. Eclogite and high‐P granulite facies metamorphism in the Silverstreet domain may coincide with a ≈570–535 Ma event documented in the western Charlotte belt or to a late Ordovician‐early Silurian event. The occurrence of these high‐P assemblages within the Carolina terrane implies that, prior to this event, the western Carolina terrane (Charlotte belt) and the eastern Carolina terrane (Carolina Slate belt) formed separate terranes. The collisional event represented by these high‐pressure assemblages implies amalgamation of these formerly separate terranes into a single composite terrane prior to its accretion to Laurentia.
Eclogites from the south Tianshan, NW China: petrological characteristic and calculated mineral equilibria in the Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O system
Authors: Wei C. J. , Powell R. , Zhang L. F.
Published: March 2003

Eclogites from the south Tianshan, NW China are grouped into two types: glaucophane and hornblende eclogites, composed, respectively, of garnet + omphacite + glaucophane + paragonite + epidote + quartz and garnet + omphacite + hornblende (sensu lato) + paragonite + epidote + quartz, plus accessory rutile and ilmenite. These eclogites are diverse both in mineral composition and texture not only between the two types but also among the different selected samples within the glaucophane eclogite. Usingthermocalc3.1 and recent models of activity–composition relation for minerals, aP–Tprojection and a series ofP–Tpseudosections for specific samples of eclogite have been calculated in the system Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O (NCFMASH) with quartz and water taken to be in excess. On the basis of these phase diagrams, the phase relations andP–Tconditions are well delineated. The three selected samples of glaucophane eclogite AK05, AK11 and AK17 are estimated to have peakP–Tconditions, respectively, of 540–550 °C atc. 16 kbar,c. 560 °C at 15–17 kbar andc.580 °C at 15–19 kbar, and two samples of hornblende eclogite AK10 and AK30 of 610–630 °C and 17–18 kbar. Together with H2O‐content contours in the relatedP–Tpseudosections and textural relations, both types of eclogite are inferred to show clockwiseP–Tpaths, with the hornblende eclogite being transformed from the glaucophane eclogite assemblage dominantly through increasing temperature.
ACID‐BASE IN RENAL FAILURE: Acidosis and Nutritional Status in Hemodialyzed Patients
Authors: Chauveau Phillipe , Fouque Denis , Combe Christian , Laville Maurice , Canaud Bernard , Azar Raymond , Cano Noel , Aparicio Michel , Leverve Xavier ,   the French Study Group for Nutrition in Dialysis
Published: March 2003

In a cross‐sectional study of more than 30% of French dialysis patients (N = 7,123), we evaluated the relationships between predialysis plasma bicarbonate concentration and nutritional markers. Data including age, gender, cause of end‐stage renal disease (ESRD), time on dialysis, body mass index (BMI), blood levels of midweek predialysis albumin, prealbumin, and bicarbonate were collected. Normalized protein catabolic rate (nPCR), dialysis adequacy parameters, and estimation of lean body mass (LBM) were computed from pre‐ and postbicarbonate‐dialysis urea and creatinine levels according to the classical formulas of Garred. Average values (±1 SD) were age 61 ± 16 years, BMI 23.3 ± 4.6 kg/m2, dialysis time 12.4 ± 2.7 h/week, HCO3 22.8 ± 3.5 mmol/L, albumin 38.7 ± 5.3 g/L, prealbumin 340 ± 90 mg/L, Kt/V 1.36 ± 0.36, nPCR 1.13 ± 0.32 g/kg BW/day, and LBM 0.86 ± 0.21% of ideal LBM. A highly significant negative correlation was observed between predialysis bicarbonate levels (within a range of 16–30 mmol/L, 95% of this population) and nPCR confirmed by analysis of variance using bicarbonate classes (p < 0.0001). Bicarbonate was also negatively correlated with albumin, prealbumin, BMI, and LBM. No relationship was noted between bicarbonate and Kt/V despite a positive correlation between Kt/V and nPCR. It is likely that a persistent acidosis observed despite standard bicarbonate dialysis was caused by a high dietary protein intake which results in an increased acid load, but also overcomes the usual catabolic effects of acidosis.
Upper Limb Ischemia After Vascular Access Surgery: Differential Diagnosis and Management
Authors: Miles Anne Marie
Published: March 2003

Hand ischemia following placement of upper limb arterio‐venous accesses for dialysis may result in debilitating complications and contribute to morbidity and mortality on dialysis. Two distinct clinical variants of hand ichemia are recognized: vascular steal syndrome, in which a spectrum of severity of ischemic changes affect all tissues of the hand; and ischemic monomelic neuropathy, where ischemia is confined to the nerves of the hand. Early diagnosis and treatment of these complications (often including closure of the access) is imperative to prevent hand paralysis, and digital or hand amputation.
Comorbidity Assessment in Hemodialysis and Peritoneal Dialysis Using the Index of Coexistent Disease
Authors: Athienites Nicolaos V. , Miskulin Dana C. , Fernandez Gladys , Bunnapradist Suphamai , Simon Gertrude , Landa Marcia , Schmid Christopher H. , Greenfield Sheldon , Levey Andrew S. , Meyer Klemens B.
Published: March 2003

The purpose of this paper is to describe the ICED, summarize outcomes of prior studies in which it was used, and describe the adaptations that have lead to the present instrument. We will then demonstrate its use in quantifying the burden of comorbid conditions in a sample of hemodialysis and peritoneal dialysis patients from our center, and show the relationship between ICED levels and outcomes in peritoneal dialysis patients.
Initial Experience of a Nephrologist‐Operated Vascular Access Center
Authors: Jackson Jerry W. , Lewis James L. , Brouillette John R. , Brantley Roman R.
Published: March 2003

A nephrology practice in Alabama did not feel in control of vascular access management. Scheduling delays, as well as variable techniques and outcomes, leading to high morbidity and mortality, caused frustration with the existing care system for vascular access. Our objective was to develop an integrative system of vascular access care, involving nephrologists along with the other caregivers, and to demonstrate an improvement in outcomes. Nephrology Vascular Labs (NVL), a recent RMS‐Lifeline acquisition, opened a vascular access center (VAC) as an extension of the nephrology practice. Both pre‐ESRD and ESRD patients are evaluated and treated in the VAC. Treatment is rendered in a timely fashion, to the benefit of the patients. Nephrologists serve as the interventionists. More than 90% of vascular access problems detected at dialysis are treated at the VAC. More than 2000 procedures have been performed over 2 years. Procedures carried out include thrombolysis with angioplasty, fluoroscopy alone or with angioplasty, placement of cuffed and noncuffed catheters, removal of cuffed catheters, and minor surgeries. Success rates have been high. Minor and major complications have been relatively low. Referrals to both surgeons and radiologists are shown to emphasize the role of the VAC as part of an integrative system of vascular access care. Results of a patient satisfaction survey were excellent. The VAC has fulfilled the vision of creating a seamless integration of care for vascular access. Hospitalization rate has been reduced and it is suspected that the global cost of access care is markedly lower than prior to the VAC. Multiple nephrologists can rotate as the VAC's interventionist and jointly obtain good outcomes and have little variability among them. Several reasons for using a nephrologists as the interventionist are discussed.
Ethical Issues in Dialysis Aaron Spital, Series Editor: Quality End‐of‐Life Care in Dialysis Units
Authors: Davison Sara N.
Published: March 2003

Quality end‐of‐life care has not been a priority in dialysis units and patients often experience prolonged dying while suffering needlessly. Advance directives (ADs) and decisions to stop dialysis have been highlighted by the medical profession as priorities in improving the quality of care, yet these are only two aspects of end‐of‐life care. They may not reflect patients' priorities and may not have the expected impact in improving the quality of end‐of‐life care. This review argues that quality end‐of‐life care should be a clinical priority in the care of dialysis patients; end‐of‐life care needs to be developed primarily from the patients' perspective; a clinical framework is required that integrates many aspects of end‐of‐life care; and end‐of‐life care should be initiated much earlier in the course of patients' illnesses than traditionally is done. By communicating more effectively and sooner with patients, their values and needs can be identified so we will be better able to plan and facilitate their end‐of‐life care and improve their experience of dying.
Properties of Membranes Used for Hemodialysis Therapy
Authors: Clark William R. , Gao Dayong
Published: March 2003

Recent trends show a progressive increase in the use of modified cellulosic and synthetic dialyzers and a corresponding decrease in the utilization rate of unmodified cellulosic dialyzers. The purpose of this article is to describe current membrane and dialyzer technology, with the focus almost entirely on modified cellulosic and synthetic membranes. A general overview of membrane‐related determinants of dialyzer performance is first presented, followed by a discussion of specific characteristics of some of the more commonly used membranes and dialyzers.
Comparison and Survival of Hemodialysis and Peritoneal Dialysis in the Elderly
Authors: Collins Allan J. , Weinhandl Eric , Snyder Jon J. , Chen Shu‐Cheng , Gilbertson Dave
Published: March 2003

Comparisons of clinical outcomes in hemodialysis (HD) and peritoneal dialysis (PD) patients have been marked by inconsistent results depending on the population studied and the methods used. In order to address this limitation of previous U.S. studies and to more specifically evaluate the higher‐risk elderly population, we undertook a study of Medicare patients ≥67 years of age and assessed the comorbidity before they entered end‐stage renal disease (ESRD) treatment. We then evaluated their survival outcomes at 6 month intervals in the follow‐up period. In order to adequately assess the comorbidity we employed the Charlson comorbidity index and applied it to the comorbidity of the ESRD population up to 2 years before ESRD to characterize conditions from the start of ESRD treatment. We also counted inpatient hospital days in the 2 years prior to initiation of ESRD therapy as a marker of severity of disease. These two determinants of comorbidity were used to adjust the analysis along with other demographic and laboratory data. In the diabetic population, HD patients are shown to have a decreased risk of death, with the decrease ranging from 8% [relative risk (RR) (HD:PD) 0.82, 95% confidence interval (CI) 0.75–0.90] at month 6 to 54% [RR (HD:PD) 0.46, 95% CI 0.30–0.70] at month 48. In the nondiabetic population, HD patients are shown to have a 17% [RR (HD:PD) 1.17, 95% CI 1.07–1.28] increased risk of death in the first 6 months, and a decreased risk of death from months 6 to 48, a decrease ranging from 17% to 34%. Relative risks were significantly different from 1.0 at all intervals. These overall findings suggest that in the elderly population in the United States treated with PD had outcomes that were significantly worse than their HD patient counterparts, even after adjusting basic patient demographics, the comorbidity index, severity of disease with hospital days, demographics, and glomerular filtration rate (GFR) at the time of start of dialysis.
Quality of Life and Rehabilitation of Elderly Dialysis Patients
Authors: Kutner Nancy G. , Jassal Sarbjit V.
Published: March 2003

Chronologic age per se does not measure the ability of an individual to benefit from dialysis. Elderly patients gain added lifetime on dialysis that is satisfying, and elderly patients as a group often show better psychosocial adjustment to dialysis than do younger patients. However, the limitations in physical functioning that characterize chronic dialysis patients increase with patient age. The clinical challenge is to identify factors that contribute to patients' compromised functioning and to arrange targeted supportive services. An integrated comprehensive program can address elderly dialysis patients' multiple care needs. Strategies that improve outcomes by reducing the risks of elderly persons for increased disability, assisting them to function in their usual environment whenever possible, can also have benefits.
Special Clinical Problems in Geriatric Patients
Authors: Winchester James F.
Published: March 2003

The elderly dialysis patient presents several challenges to the nephrologist. Concurrent illnesses may complicate management, disabilities may interfere with mobility, hearing, and vision, and depression and mental incompetence may be present. For these reasons the physician and health care team should adopt a broad treatment plan, using expert help if needed in managing the patient and involving family members, clergy, and friends. While lifestyle changes are inevitable for the elderly with initiation of dialysis, satisfactory outcomes are possible. In the event of overwhelming illness and the patient's perception of the futility of continuation of dialysis, cessation of dialysis must be approached in a humane, considerate, and compassionate manner.
Phase II Trial of the Antiestrogen Toremifene for Androgen‐Independent Prostate Cancer
Authors: Smith Matthew R. , Kantoff Philip W. , Oh William , Elson Grace , Manola Judith , McMullin Margaret , Jacobsen Joseph , Brufsky Adam , Kaufman Donald
Published: March 2003

Objectives: Estrogen receptors are expressed in healthy and malignant prostate epithelium. Previous studies of the antiestrogen tamoxifen (20–100 mg po qd) for recurrent or metastatic prostate cancer (CaP) reported response rates of 0–23%. These studies may have underestimated the activity of antiestrogens, however, because of their reliance on insensitive clinical and radiographic response criteria. In addition, treatment‐related increases in androgen levels among men who initiated treatment with noncastrate testosterone levels may have confounded the results. The aims are to evaluate the activity of the antiestrogen toremifene, a triphenylethylene derivative antiestrogen related chemically and pharmacologically to tamoxifen, in men with androgen‐independent CaP using prostate specific antigen (PSA) response criteria and to determine the effect of toremifene treatment on serum testosterone levels in castrated men.

Materials and Methods: Fifteen men (median age 71 years; median PSA 58.5 ng/ml) with castrate testosterone levels, no disease‐related symptoms, and rising PSA after androgen deprivation and antiandrogen withdrawal were treated with toremifene, 60 mg po qd, until it was determined that the patient was not responding to treatment. Nonresponse to treatment was defined as symptomatic disease progression or a PSA level 150% study nadir on two determinations at least 4 weeks apart. Response was defined as >50% PSA decrease on two determinations at least 4 weeks apart.

Results: Twelve men were evaluable for response. Median time to determination of nonresponse to treatment was 16 weeks (range 8 to 19 weeks). There were no responses to treatment (response rate 0%; 95% confidence interval 0–22%). Treatment did not significantly change serum testosterone levels.

Conclusions: These results indicate that toremifene is inactive for the treatment of androgen‐independent CaP and suggest that antiestrogens should not be used routinely as secondary hormonal therapy. The treatment of castrated men with toremifene does not significantly change serum testosterone levels.