bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geochemical constraints of the eclogite and granulite facies metamorphism as recognized in the Raobazhai complex from North Dabie Shan, China
Authors: Xiao Y. L. , Hoefs J. , Van Den Kerkhof A. M. , Li S. G 
Published: March 2003

AbstractA combined study of major and trace elements, fluid inclusions and oxygen isotopes has been carried out on garnet pyroxenite from the Raobazhai complex in the North Dabie Terrane (NDT). Well‐preserved compositional zoning with Na decreasing and Ca and Mg increasing from the core to rim of pyroxene in the garnet pyroxenite indicates eclogite facies metamorphism at the peak metamorphic stage and subsequent granulite facies metamorphism during uplift. A P–T path with substantial heating (from c. 750 to 900 °C) after the maximum pressure reveals a different uplift history compared with most other eclogites in the South Dabie Terrane (SDT). Fluid inclusion data can be correlated with the metamorphic grade: the fluid regime during the peak metamorphism (eclogite facies) was dominated by N2‐bearing NaCl‐rich solutions, whereas it changed into CO2‐dominated fluids during the granulite facies retrograde metamorphism. At a late retrograde metamorphic stage, probably after amphibolite facies metamorphism, some external low‐salinity fluids were involved. In situ UV‐laser oxygen isotope analysis was undertaken on a 7 mm garnet, and impure pyroxene, amphibole and plagioclase. The nearly homogeneous oxygen isotopic composition (δ18OVSMOW = c. 6.7‰) in the garnet porphyroblast indicates closed fluid system conditions during garnet growth. However, isotopic fractionations between retrograde phases (amphibole and plagioclase) and garnet show an oxygen isotopic disequilibrium, indicating retrograde fluid–rock interactions. Unusual MORB‐like rare earth element (REE) patterns for whole rock of the garnet pyroxenite contrast with most ultra‐high‐pressure (UHP) eclogites in the Dabie‐Sulu area. However, the age‐corrected initial εNd(t) is − 2.9, which indicates that the protolith of the garnet pyroxenite was derived from an enriched mantle rather than from a MORB source. Combined with the present data of oxygen isotopic compositions and the characteristic N2 content in the fluid inclusions, we suggest that the protolith of the garnet pyroxenite from Raobazhai formed in an enriched mantle fragment, which has been exposed to the surface prior to the Triassic metamorphism.
Crack‐fill porphyroblastesis
Authors: Barker Andrew J. 
Published: March 2003

AbstractGarnet‐mica schists from the Scottish Highlands provide new insight into an important mechanism of phyllosilicate growth, termed ‘crack‐fill porphyroblastesis’. It is shown that grain boundary dilatancy, microcracking and porphyroblast‐matrix decoupling all play a significant role in facilitating growth in regimes of noncoaxial shear. With respect to chlorite porphyroblasts, there are three growth stages. Following nucleation, the initial phase of growth is by progressive matrix replacement, to preserve inclusion trails of fine carbonaceous material. The second growth stage produced new optically continuous inclusion‐free chlorite on the {001} margins of those crystals at a high angle to the schistosity. This growth results from decoupling at the porphyroblast–matrix contact on those margins at a high angle to the principal axis of extension. The development of dilatant cracks at porphyroblast margins provides a sink for material migrating down Pf and chemical potential gradients. This causes precipitation of new optically continuous ‘clear’ chlorite on the pre‐existing, heavily included core. The porphyroblast–matrix boundary continues to dilate after porphyroblast growth had terminated, producing plano‐convex quartz‐rich strain shadows. Similar growth behaviour is recognised in biotite porphyroblasts, indicating that ‘crack‐fill porphyroblastesis’ is an important growth mechanism for phyllosilicates in actively deforming metamorphic rocks. It also indicates that decoupling and crack‐fill development at porphyroblast margins could be important in controlling the pattern of material transfer, and may have significant implications for matrix permeability and fluid‐flow characteristics.
The development of spiral‐shaped inclusion trails during multiple metamorphism and folding
Authors: Bell T. H. , Chen A. 
Published: March 2003

AbstractThree periods of mineral growth and three generations of spiral‐shaped inclusion trails have been distinguished within folded rocks of the Qinling‐Dabie Orogen, China, using the development of three successive and differently trending sets of foliation intersection axes preserved in porphyroblasts (FIAs). This progression is revealed by the consistent relative sequence of changes in FIA trends from the core to rim of garnet porphyroblasts in samples with multiple FIAs. The first and second formed sets of FIAs trend oblique to the axial planes of macroscopic folds that dominate the outcrop pattern in this region. The porphyroblasts containing these FIAs grew prior to the development of the macroscopic folds, yet the FIAs do not change orientation across the fold hinges. The youngest formed FIAs (set 3) lie subparallel to the axial planes of these folds and the porphyroblasts containing these FIAs formed in part as the folds developed. The deformation associated with all three generations of spiral‐shaped inclusion trails in garnet porphyroblasts involved the formation of subhorizontal and subvertical foliations against porphyroblast rims accompanied by periods of garnet growth; pervasive structures have not necessarily formed in the matrix away from the porphyroblasts. The macroscopic folds are heterogeneously strained from limb to limb, doubly plunging and have moderately dipping axial planes. The consistent orientation of Set 1 FIAs indicates that the development of spiral‐shaped inclusion trails in porphyroblasts with FIAs belonging to Set 2 did not involve rotation of the previously formed porphyroblasts. The consistent orientation of Sets 1 and 2 FIAs indicate that the development of spiral‐shaped inclusion trails in porphyroblasts with FIAs belonging to Set 3 did not involve rotation of the previously formed porphyroblasts during folding. This requires a fold mechanism of progressive bulk inhomogeneous shortening and demonstrates that spiral‐shaped inclusion trails can form outside of shear zones.
ACID‐BASE IN RENAL FAILURE: Use of Different Buffers in Peritoneal Dialysis
Authors: Feriani Mariano 
Published: March 2003

ABSTRACTA buffer is included in the peritoneal dialysis solution in order to offset the hydrogen ions normally produced during the metabolic processes. Nowadays, the buffer used is lactate, and its concentration in conventional peritoneal dialysis fluids is 35 or 40 mmol/L. Despite the general thought that peritoneal dialysis adequately corrects uremic acidosis, several studies have demonstrated that more than 50% of patients present mild to moderate acidosis with the solution containing 35 mmol/L of lactate, although with a 40 mmol/L solution this percentage decreases, a substantial number of patients still remain acidotic. This acid‐base derangement is characterized by a normal pH and a below‐normal plasma bicarbonate concentration, although the external body base balance is in equilibrium. There is evidence that this condition contributes to uremic osteodystrophy and has a detrimental effect on protein metabolism. Conventional solutions also affect mesothelial cell viability and local leukocyte function and have potential systemic effects such as the impairment of cellular redox state. New solutions containing pure bicarbonate or a mixture of bicarbonate and lactate have recently been investigated. A bicarbonate solution containing 34 mmol/L significantly increased plasma bicarbonate levels as compared with the lactate 35 mmol/L solution. It has been demonstrated that bicarbonate solutions have better biocompatibility than the lactate buffered solution and substantially reduce abdominal discomfort experienced by a certain percentage of patients during the solution infusion. These studies demonstrated that the bicarbonate‐buffered CAPD solution is safe, well‐tolerated, and does not present any, even potential, side effects. Thus, it seems reasonable to consider the bicarbonate buffered solution the standard instead of the alternative, and it might entirely replace lactate as buffer in peritoneal dialysis fluid.
Racial Inequity in America's ESRD Program
Authors: Reddan Donal N. , Szczech Lynda Anne , Klassen Preston S. , Owen William F. 
Published: March 2003

ABSTRACTThe end‐stage renal disease (ESRD) program has a significant overrepresentation of racial and ethnic minority groups. The increased susceptibility of nonwhite populations to ESRD has not been fully explained and probably represents a complex interplay of genetic, cultural, and environmental influences. Because the program delivers care under a uniform health care payment system, it represents a unique environment in which to explore variation in health care delivery. A number of disparities in outcomes and delivery of ESRD care have been noted for racial minority participants. These include possible overdiagnosis of hypertensive nephrosclerosis, decreased provision of renal replacement therapy, limited referral for home dialysis modalities, underprescription of dialysis, increased use of synthetic grafts rather than fistulas as permanent angioaccess, and delayed wait‐listing for renal transplantation. Transplantation inequities mean that black patients are likely to remain on dialysis relatively longer, so that their susceptibility to less than optimal processes of care increases disproportionately. Improved survival and quality of life (QOL) for blacks with ESRD may have encouraged provider complacency about racial disparities in the ESRD program and in particular about referral for transplantation. It is also apparent that minority ESRD patients may, similar to their non‐ESRD counterparts, be referred less frequently for invasive cardiovascular (CV) procedures. Despite these observations of inequality in ESRD care, the adjusted mortality for minority participants in the ESRD program are better than for the majority population. This seeming paradox may define an opportunity to improve outcomes for minorities with ESRD even more.
Dialysis‐Related Amyloidosis After Renal Transplantation
Authors: Campistol Josep M. 
Published: March 2003

ABSTRACTThere is no effective therapy for dialysis‐related amyloidosis (DRA). The restoration of renal function with a functional graft seems the most reasonable therapy for this disturbing disease. Although there are not many prospective series on the efficacy of renal transplantation for DRA, all the studies agree that most of the patients experienced a significantly clinical improvement of the articular symptoms after a successful renal transplantation. Nevertheless, radiologic (bone cysts) and histologic lesions did not disappear after long‐term follow‐up.
Blood Flow Surveillance of Hemodialysis Grafts and the Dysfunction Hypothesis
Authors: Paulson William D. 
Published: March 2003

ABSTRACTIt is widely recommended that hemodialysis graft surveillance programs should be implemented and that significant stenosis should be corrected when it is accompanied by graft dysfunction. The rationale for surveillance depends on the dysfunction hypothesis, which states that stenosis causes graft dysfunction [such as a decrease in graft blood flow (Qa)], and this dysfunction reliably precedes and accurately predicts thrombosis. The usefulness of Qa surveillance depends on accurate prediction of thrombosis so that stenosis can be corrected prior to thrombosis. An analysis of the dysfunction hypothesis indicates that some or all of its underlying assumptions are invalid. Most importantly, the presence of wide hemodynamic variation during Qa measurements makes Qa a relatively inaccurate predictor of thrombosis. A number of studies have evaluated the value of surveillance with intervention in reducing thrombosis rates and prolonging graft life. Review of these studies show that few have been prospective and randomized, and many have included historical control groups. It is debatable whether these studies have established that Qa surveillance with intervention should be applied to all grafts. Data from several studies suggest that severity of stenosis may be at least as accurate as Qa in predicting thrombosis. Consequently, inclusion of stenosis measurements (e.g., by duplex ultrasound) may improve the results of surveillance. These unresolved issues indicate it is premature to recommend routine Qa surveillance with intervention of all hemodialysis patients with grafts.
Factors Affecting Hemodialysis and Peritoneal Dialysis Efficiency
Authors: Ronco Claudio , Clark William 
Published: March 2003

ABSTRACTHemodialysis and peritoneal dialysis are two blood purification techniques that use similar operating systems. The hemodialysis system is based on three components (blood, membrane, and dialysate). The peritoneal dialysis system is based on the same components that can, however, be less manipulated and adjusted. In hemodialysis the blood flow is the main determinant of small solute removal thanks to a prevalently diffusive mechanism. Convection is also used to transport larger solutes across the membrane, but this mechanism relies on the high permeability coefficient of the membrane and high transmembrane pressure leading to high ultrafiltration rates. The membrane can therefore influence the performance of the techniques as far as solute removal and ultrafiltration are concerned. Finally, diffusion is facilitated by an improved distribution of dialysate flow in the dialysate compartment. This can be achieved with a special dialysate pathway configuration based on space yarns or micronodulation of the fibers. In peritoneal dialysis, blood flow and membrane characteristics can be less manipulated or almost not at all. The only variables are dialysate volume, flow, dwell time, and composition. Thanks to modification in these aspects of the dialysate, peritoneal dialysis techniques with different clearances and ultrafiltration rates can be accomplished.
Quantification of Middle Molecular Weight Solute Removal in Dialysis
Authors: Henderson Lee W. , Clark William R. , Cheung Alfred K. 
Published: March 2003

ABSTRACTThe pioneering work of Gotch emphasized the critical need to be quantitative with respect to treatment prescription. Through his meticulous derivations and analyses regarding Kt/Vurea, he has provided powerful insight into the standard therapy prescriptions that we now employ clinically. However, time has seen the proliferation of treatment techniques, most of which are too “young” to have been characterized with respect to clinical outcomes. Further, the relationship between removal of urea and removal of middle molecular size solutes associated with these newer techniques deviates from that associated with conventional, clinically qualified techniques. In this article we examine the solute clearance profile of some of these new methodologies and their relationship to current criteria for treatment adequacy. Our approach is to discuss components of the overall transport process and then utilize modeling of surrogate molecules over the size range of interest whose transport characteristics are known. Alteration in the solute clearance profile of these surrogate markers in response to changes in prescription variables will thus offer insight into the spectrum of toxic middle molecules that are removed when size, space of distribution, and generation rate are known.
Past, Present, and Future of Quantified Peritoneal Dialysis
Authors: Haq Naveed U. , Nolph Karl D. 
Published: March 2003

ABSTRACTThe role of peritoneal dialysis (PD) as a modality in renal replacement therapy has been well established. In this article we review various aspects in the evolution of PD, with special emphasis on adequacy. Until the late 1950s PD was still considered as a last resort in the treatment of terminal uremia. The introduction of a chronic indwelling catheter made chronic PD possible. The concept of continuous ambulatory peritoneal dialysis (CAPD), proposed in 1975, had a major impact on the way PD was performed later. The value of determining the adequacy, using urea clearance normalized to total body water (Kt/V) or creatinine clearance normalized to body surface area, was clearly highlighted by the Canada‐USA (CANUSA) study. Introduction of standardized peritoneal equilibration tests has been very helpful in enhancing the efficiency of PD. In 1995 the National Kidney Foundation‐Dialysis Outcomes Quality Initiatives (NKF‐DOQI) established guidelines to improve patient survival and outcome on dialysis. These guidelines established minimum criteria for PD adequacy. Compliance and malnutrition remain important factors determining the efficacy of PD. The “healthy start” concept emphasizes an early start of dialysis in patients with end‐stage renal disease (ESRD). The quest for an ideal PD modality has recently led to renewed interest in the idea of continuous flow peritoneal dialysis (CFPD). PD continues to grow and at the same time faces many challenges. Its role as a renal replacement therapy is likely to evolve further in the years to come.
Imaging in the Dialysis Patient: Renal Imaging in Patients Requiring Renal Replacement Therapy
Authors: Cowie Alistair 
Published: March 2003

AbstractRecent advances in imaging technology and interventional radiologic procedures have resulted in an increased variety of radiological techniques that can be used to assess patients who present with renal failure and require renal replacement therapy. This chapter provides an overview of the relative strengths and weaknesses of the available imaging methods. In particular, it covers the expanding role of the cross‐sectional, noninvasive, multiplanar imaging techniques such as gray‐scale and Doppler ultrasound, magnetic resonance imaging (MRI) and angiography (MRA), and nonenhanced helical or multislice computed tomography (CT). These imaging methods are increasingly replacing those used in the past, such as the conventional radiographic urogram, which requires a high dose of intravenous contrast media, and digital subtraction arteriography. The chapter also covers the radiologic investigation of complications of acquired renal cystic disease, including renal cell carcinoma, hemorrhage, cyst infection and rupture, and nephrolithiasis.
Incidental Carcinoma of the Prostate in the PSA Era
Authors: Galejs Laris E. , Hollander Jay B. 
Published: March 2003

Background: Prostate cancer has classically been discovered in 10% of prostatectomy specimens from presumed benign disease. Our objective was to review incidental cancer in transurethral prostatectomy (TURP) specimens and to establish whether or not the incidence, presentation, and pathology have changed since the advent of prostate specific antigen (PSA). Methods: Five hundred and thirty patients underwent TURP for presumed benign disease at our institution in 1985 (before PSA), and 481 underwent TURP between 1994 and 1995. The charts of all patients with cancer were reviewed. Patients with known cancer preoperatively were excluded. Charts were reviewed with regard to indication for TURP, presentation, age, size of prostate, digital rectal exam, PSA, and pathology report. The most recent preoperative PSA value was utilized. Pathologic factors included the weight (grams resected), grade, and extent of tumors. Stage T1a tumors were defined as having Gleason scores of <6 and volumes of <5%. If the percentage of volume was not given, the specimen was considered to be Stage T1a if cancer was present in three chips or less. All other tumors were considered Stage T1b disease. Results: In 1985, Stage T1a cancer comprised 4% of specimens, and Stage T1b comprised 6%. In 1994 and 1995, Stage T1a cancer comprised 4%, but Stage T1b comprised 3%. This change in the incidence of T1b disease was statistically significant with a p value of 0.04. There was no difference with regard to patient age, specimen weight, or Gleason score. Urinary retention was a more common indication for TURP in 1994 and 1995. Conclusions: Our findings suggest that PSA screening has decreased the incidence of Stage T1b prostate cancer.
A Critical Evaluation of Prostate Specific Antigen Parameter Responses to Manipulation According to Prostatic Histology
Authors: Alexandrou Kyriacos , Collins Gerald N. , Wynn‐Davies Alison , O'Reilly Patrick H. 
Published: March 2003

Introduction: The degree of increase in prostate specific antigen (PSA) forms after prostatic manipulation may differ depending on histology. We sought to critically evaluate this hypothesis and to examine possible clinical implications. Methods: A series of 198 men referred for transrectal ultrasound‐guided biopsy on clinical grounds had free (fPSA) and total PSA (tPSA) levels determined before undergoing biopsy and 30 min after biopsy. A subset of 100 men had the same analysis immediately before and 30 min after digital rectal examination (DRE). Geometric mean ratios and two‐sample t tests compared the change in levels of fPSA, PSA, the ratio of fPSA to tPSA (f/t PSA), fPSA density, and PSA density after manipulation to prostatic histology. Results: After undergoing biopsies, 57 men (29%) received a diagnosis of prostate cancer. The biopsy significantly altered all parameters. The degree of change was less in the malignant group for all parameters, although this only approached statistical significance for PSA and PSA density levles (p = 0.159 and p = 0.170, respectively). In the DRE group, the PSA changes were similar, although the cancer patients tended to release slightly less PSA forms (PSA, p = 0.376; fPSA, p = 0.657; f/t PSA, p = 0.396). Conclusion: PSA release and PSA parameter alteration after manipulation differ in the neoplastic prostate. The subtlety of change after DRE currently limits clinical application.
Expression of Prostate Specific Molecules in Bacille Calmette‐Guerin: An Immunotherapeutic Approach to Prostate Cancer
Authors: Zeoli Christina D. , Maitland Michael , Rose Herbert , Bloom Barry , Mittelman Abraham , Geliebter Jan 
Published: March 2003

ABSTRACTObjective: The objective is to develop an immunotherapeutic vaccine for the treatment of metastatic prostate cancer.Results: Bacille Calmette Guerin (BCG) were engineered to express prostate specific antigen (PSA) or prostate specific membrane antigen (PSMA). Western blotting techniques indicate that recombinant BCG (rBCG) express approximately 25 ng PSA or 112 pg PSMA per 1 μg microgram of protein in rBCG bacterial lysates. Discussion: BCG, the vaccine for tuberculosis, is a potent immunologic adjuvant stimulating both the humoral and cell‐mediated immune systems. Prostate cancer patients can generate cytotoxic lymphocytes against specific peptides from normal, self‐molecules such as PSA and PSMA. Therefore, a rBCG vaccine that expresses prostate specific proteins may stimulate an immune response to recognize and destroy prostate cancer cells.Conclusion: BCG can be engineered to express prostate specific molecules and may be useful as an immunotherapeutic vaccine against prostate cancer.