bluuebunny/crossref_metadata_2025 huggingface dataset:
Baseline and stress‐induced glucocorticoids during reproduction in the variable flying fox, Pteropus hypomelanus (Chiroptera: Pteropodidae)
Authors: Reeder Deeann M. , Kunz Thomas H. , Widmaier Eric P.
Published: July 2004

Baseline and stress‐responsive glucocorticoid (GC) levels were assessed during early pregnancy, late pregnancy, and lactation in female variable flying foxes (Pteropus hypomelanus) and in males over the same time period. Animals were maintained in a breeding colony in captivity. High levels of both cortisol and corticosterone were detected, with total plasma GC levels being among the highest documented in vertebrates (up to 3000 ng/ml in individual animals, with cortisol being the primary GC, accounting for ≈78% of total GCs), and significantly greater in males than in females. Plasma levels of cortisol and corticosterone showed nearly identical profiles within each sex, with the exception of females in late pregnancy, in which corticosterone, but not cortisol, increased significantly. Baseline levels of plasma cortisol were highest in September (when pups were between 1 and 2 months of age) in both sexes, which may be related to the approaching onset of the mating period. There was a continuum in the magnitude of the response to stress (handling and sampling) over time in females, with the greatest stress response in early pregnancy, a dampened response during late pregnancy, and no significant stress response during lactation. Surprisingly, males failed to exhibit elevated GCs after this stress, but did have significant stress‐induced hyperglycemia and suppression of plasma testosterone levels. This may be due to their high (perhaps maximal) baseline levels, which suggests that being in a breeding group was chronically stressful for males. J. Exp. Zool. 301A:682–690, 2004. © 2004 Wiley‐Liss, Inc.
cDNA cloning and mRNA expression of a FTZ‐F1 homologue from the pituitary of the orange‐spotted grouper, epinephelus coioides
Authors: Zhang Weimin , Li Xin , Zhang Yong , Zhang Lihong , Tian Jing , Ma Guangzhi
Published: July 2004

A FTZ‐F1 homologue was cloned from the pituitary cDNA library of the orange‐spotted grouper. The full‐length cDNA of the orange‐spotted grouper FTZ‐F1 spanned 1735 bp including a poly (A) tail. The open reading frame encodes a protein of 468 amino acids. Sequence analysis indicated that it had a structure typical of the orphan nuclear receptor superfamily, and the FTZ‐F1 box, a characteristic of the FTZ‐F1 family. Phylogenetic analysis indicated that the orange‐spotted grouper FTZ‐F1 was closely related to medaka FTZ‐F1 and did not belong to either the SF–1/Ad4BP group or the LRH–1/FTF group. Virtual Northern Blot detected a major transcript of about 1.7 kb and a minor transcript of 2.2 kb of FTZ‐F1 in the orange‐spotted grouper pituitary gland. The expression of FTZ‐F1 homologue gene in different tissues and during embryonic development of the orange‐spotted grouper was determined using one‐step RT‐PCR coupled with Southern blot analysis. In addition to the pituitary gland, the orange‐spotted grouper FTZ‐F1 was also expressed in the hypothalamus, forebrain, heart, liver, kidney, and ovary. The stronger signal from the gel image indicated that the expression level of FTZ‐F1 homologue gene was higher in the ovary of stage 3 than stage 2. During embryonic development, mRNA for the orange‐spotted grouper FTZ‐F1 homologue was present in newly fertilized eggs, but disappeared in embryos at 50 min post fertilization. The orange‐spotted grouper FTZ‐F1 homologue mRNA reappeared in embryos at 1.5 hr post fertilization. Its expression level was increased from late blastula to neurula stages. Taken together, results of the current study suggest that the orange‐spotted grouper FTZ‐F1 homologue exhibits characteristics indicative of both the LRH‐1/FTF‐ and the SF–1/Ad4BP‐like genes, and may also play important roles in the hypothalamus‐pituitary‐gonadal axis, cholesterol metabolism, and embryogenesis. J. Exp. Zool. 301A:691–699, 2004. © 2004 Wiley‐Liss, Inc.
Jewish ethnicity and Black race: Contrasting influences on the prognosis of breast cancer
Authors: Donegan William L. , Tjoe Judy A.
Published: July 2004

Background and Objectives

For reasons that are incompletely understood, race and ethnicity are associated with differing mortality from breast cancer. This investigation was undertaken to evaluate racial and ethnic influences on survival of women with breast cancers and to identify influential factors.

Methods

A population of 766 racially and ethnically defined women with newly diagnosed invasive breast cancers in a clinical practice were prospectively evaluated and observed on a continuing basis. Survivals were compared with multiple demographic and clinicopathologic variables.

Results

Compared to White, non‐Jewish patients, no significant difference was found in survival of Jewish patients. Stage of cancers at diagnosis and measures of tumor biology were also comparable. By contrast, the survival of Black patients was significantly worse than that of White patients. Advanced tumor stage at diagnosis, unfavorable tumor biology and poor ancillary health all appeared to contribute to the poor survival of Black women.

Conclusion

No adverse influence of Jewish ethnicity was found on the prognosis of breast cancer. The poor prognosis of Black women compared to White women appeared to be the result of multiple untoward influences. J. Surg. Oncol. 2004;87:61–67. © 2004 Wiley‐Liss, Inc.
Vascular endothelial growth factor in esophageal cancer
Authors: Kleespies Axel , Guba Markus , Jauch Karl‐Walter , Bruns Christiane J.
Published: July 2004

Vascular endothelial growth factor (VEGF) plays a crucial role in angiogenesis of many solid malignancies. The influence of angiogenesis and VEGF expression on progression and recurrence of esophageal cancer has been investigated over the last years. This article reviews the prognostic significance of VEGF expression, microvessel density (MVD), and lymphangiogenic factors in squamous cell carcinoma (SCC), Barrett's dysplasia, and adenocarcinoma (AC) of the esophagus, their predictive value for treatment response to chemo‐radiotherapy and new anti‐angiogenic treatment strategies. J. Surg. Oncol. 2004;87:95–104. © 2004 Wiley‐Liss, Inc.
Incidentally discovered gallbladder cancer: Role of cryotherapy
Authors: Goldberg Stephanie R. , Neifeld James P.
Published: July 2004

Background and Objectives

Carcinoma of the gallbladder is the most common malignancy of the biliary tree. There is no standard surgical approach to the treatment of gallbladder cancer. Extended cholecystectomy with partial or complete hepatic lobectomy has resulted in high morbidity and poor long‐term survival. This report describes cryotherapy of the gallbladder fossa as an alternative to liver resection in the treatment of gallbladder cancer.

Methods

A group of patients underwent cryotherapy to the gallbladder fossa for local control of gallbladder cancer. Portal lymph node dissection was performed at the same time and patients with positive lymph nodes received post‐operative chemotherapy and radiation; negative node patients were observed.

Results

Seven patients underwent surgery. Gallbladder cancer had been incidentally found in all patients. Median hospital stay was 4 days. Five patients had positive nodes. Complications included biliary stricture, pleural effusion, congestive heart failure exacerbation, and pulmonary embolus. Mean disease‐free survival for patients with T2 tumors was 11.7 months. Mean disease‐free survival for patients with T3 tumors was 16.3 months. Mean disease‐free survival for lymph node positive patients was 14.8 months compared to 13 months for node negative patients. No local recurrences have been detected in the gallbladder fossa.

Conclusions

This study suggests cryotherapy to the gallbladder fossa done concomitantly with portal lymph node dissection may represent a safe and effective alternative to hepatic resection in the treatment of gallbladder cancer. J. Surg. Oncol. 2004;87:91–94. © 2004 Wiley‐Liss, Inc.
IV‐DSA is a new diagnostic tool for axillary lymph node metastasis in breast cancer patients
Authors: Watanabe Osamu , Shimizu Tadao , Imamura Hiroshi , Kinoshita Jun , Utada Yoshihito , Okabe Toshihiro , Kimura Kiyomi , Hirano Akira , Aiba Motohiko , Ogawa Kenji
Published: July 2004

Background and Objective

The aim of this study is to know whether intravenous digital subtraction angiography (IV‐DSA) is useful to detect axillary lymph node metastasis of breast cancer and to evaluate the anigiogenesis of lymph nodes in the axilla.

Patients and Methods

Forty three primary breast cancer patients (N0: 26 cases, N1: 5 cases, N2: 2 cases) who underwent IV‐DSA between January and November 2000 were included in the study. Infinix CB apparatus (Toshiba, Japan) was used to collect IV‐DSA images and when a mass became stained in the axilla, it was considered to be metastatic. The angiogenesis was studied by examining microvessel density (MVD) after lymph node immunostaining for factor VIII. Primary tumor was detected by IV‐DSA in all 43 cases.

Results

Axillary lymph node metastases were detected by IV‐DSA in 34.9% of cases (15/43), and by pathology in 37.2% (16/43). The sensitivity, specificity, and accuracy of the diagnostic method were 75.0% (12/16), 88.9% (24/27), and 83.7% (36/43), respectively. MVD, calculated after immunostaining for factor VIII, was significantly lower in the in metastatic region of lymph nodes identified by DSA (88.5 ± 35.0) than in metastasis‐free lymph nodes (141.1 ± 34.0, P < 0.0001).

Conclusions

IV‐DSA is useful in the diagnosis of axillary lymph node metastasis of breast cancer. Our results suggest that the primary factors involved in the mechanism of DSA display may be different from high/low MVC values. J. Surg. Oncol. 2004;87:75–79. © 2004 Wiley‐Liss, Inc.
Intrahepatic cholangiocarcinoma diagnosed preoperatively as hepatocellular carcinoma
Authors: Yamamoto Masakazu , Ariizumi Shunichi , Otsubo Takehito , Katsuragawa Hideo , Katagiri Satoshi , Nakano Masayuki , Takasaki Ken
Published: July 2004

Background

Some cases of mass‐forming intrahepatic cholangiocarcinoma (ICC) are diagnosed as hepatocellular carcinoma (HCC) based on preoperative imaging and clinical findings. We investigated the backgrounds of such cases.

Methods

Sixty‐seven patients with mass‐forming ICC underwent surgery from 1980 to 2002. Twenty‐four of these patients received a diagnosis of HCC preoperatively. We compared the group diagnosed as HCC and that diagnosed as ICC. ICC was diagnosed histopathologically in all 67 patients.

Results

The specific clinical findings included high rates of associated hepatitis C virus infection, high levels of serum alpha fetoprotein, lower levels of serum CA19‐9, small dimension of the tumor, hypervascular staining on angiography or computed tomography, lower rates of lymph node metastasis, and high rates of HCC occurrence in the group diagnosed as HCC. None of the patients underwent extrahepatic bile duct resection and most patients did not undergo lymph node dissection in the group diagnosed as HCC. The rates of mucus secretion and the ductal expression of mucin core protein‐1 (MUC1) were significantly different between the subgroups. The cumulative survival rates were significantly better in the group diagnosed as HCC than in the group diagnosed as ICC.

Conclusion

Patients with ICC given a preoperative diagnosis of HCC had distinct clinical features and could be treated with the same operation as HCC patients. J. Surg. Oncol. 2004;87:80–83. © 2004 Wiley‐Liss, Inc.
Specific laboratory methodologies achieve higher model for endstage liver disease (MELD) scores for patients listed for liver transplantation
Authors: Trotter James F. , Brimhall Brad , Arjal Russ , Phillips Charles
Published: July 2004

Priority for liver transplantation is currently based on the Model for Endstage Liver Disease (MELD) score, a mathematical function which includes the following objective variables: bilirubin, creatinine (Cr), and international normalized ratio (INR). We have noted that specific laboratory methodologies may yield consistently higher values of bilirubin, Cr, and INR. Therefore, we performed a study to determine if higher MELD scores could be obtained by utilizing laboratory methodologies selected to return higher laboratory values than standard methodologies used in our hospital’s clinical laboratory. Phlebotomy was performed for routine clinical indications in 29 consecutive patients listed for liver transplantation. MELD scores were calculated using bilirubin, Cr, and INR from laboratory methods in our hospital’s clinical laboratory (designated Lab #1) and from 2 other clinical laboratories (designated Lab #2 and Lab #3). The mean MELD score in our hospital’s clinical laboratory (Lab #1) (13.6) was not significantly different than in Lab #2 (14.7), but in Lab #3, it was significantly higher by 20% (17.1), P < .03. Virtually all of the difference in MELD score between our hospital’s clinical laboratory (Lab #1) and Lab #3 could be attributed to the INR, which was significantly higher by 26% in Lab #3 (1.9) vs. Lab #1 (1.4), P < .00002. Using MELD scores calculated from our hospital’s clinical laboratory, the average change in priority for liver transplantation was from the 58th percentile to the 77th percentile (compared to Lab #3), P = .01. In conclusion, patients listed for liver transplantation at our center achieved significantly higher MELD scores and therefore a higher priority for liver transplantation by using laboratory methodologies that yield higher INR values than our hospital laboratory. The selection of laboratory methodologies may have a significant impact on MELD score. (Liver Transpl 2004;10:995-1000.)
Comparison of invasive and noninvasive measurement of plasma disappearance rate of indocyanine green in patients undergoing liver transplantation: A prospective investigator-blinded study
Authors: Faybik Peter , Krenn Claus-Georg , Baker Amir , Lahner Daniel , Berlakovich Gabriela , Steltzer Heinz , Hetz Hubert
Published: July 2004

Plasma disappearance rate of indocyanine green (PDRICG) has been proposed for assessment of liver function in liver transplants donors and recipients, in patients with chronic liver failure, and as a prognostic factor in critically ill patients. The assessment of PDRICG using a newly developed noninvasive digital pulse densitometry method was simultaneously compared to invasive aortic fiber-optic method in patients undergoing orthotopic liver transplantation (OLT). Fourteen consecutive liver transplant candidates (11 male, 3 female) were prospectively enrolled into the study. A 4F aortic catheter with an integrated fiber-optic device and a thermistor was inserted via a femoral artery sheath for invasive aortic (INV) PDRICG assessment in all patients. The fiber-optic device was connected to a computer system (COLD-Z021, PULSION Medical Systems, Munich, Germany). A finger-piece sensor was used for non-invasive (NINV) pulse-densitometric PDRICG assessment. For the PDRICG assessment .5 mg/kg of ICG in cooled saline (10-15 mL) was injected through a central venous catheter. The assessments of PDRICG were performed after induction of anesthesia, after clamping of the hepatic artery, after clamping of the inferior vena cava, after reperfusion of the graft, and on the first postoperative day. During the PDRICG measurements, the investigators were blinded for the results of the noninvasive monitoring. Seventy-one pairs of measurements were performed successfully. PDRICG ranged from 0%/min to 43.8 %/min (11.6%/min ± 9.6 %/min, mean ± SD) for invasive and from 2.6%/min to 36.1 %/min (10%/min ± 7.6 %/min, mean ± SD) for noninvasive assessment method. The linear regression analysis yielded the equation: PDRICGNINV = 1.493 ± 0.735 × PDRICGINV, with a correlation coefficient of r = 0.93 (P < .0001). The analysis according to Bland and Altman showed a good agreement between the PDRICGNINV and PDRICGINV with a mean bias 1.5 ± 3.8 for all measurements. In conclusion, according to these results, the noninvasive transcutaneous pulse-densitometric method correlates well with the invasive aortic fiber-optic method and thus can be used in patients undergoing liver transplantation. (Liver Transpl 2004;10:1060-1064.)
Outcome of liver transplantation for hepatitis B in the United States
Authors: Kim Ray W. , Poterucha John J. , Kremers Walter K. , Ishitani Michael B. , Dickson Rolland E.
Published: July 2004

Important innovations, such as hepatitis B immune globulin (HBIG) and lamivudine, have been introduced to the care of patients undergoing liver transplantation (OLT) for viral hepatitis B (HBV) (over the last 15 years). We analyzed survival of OLT recipients with HBV in the United States to examine the effect of these innovations. A retrospective analysis was conducted based on data collected prospectively by the United Network for Organ Sharing in all adult (older than 18) patients undergoing primary OLT in the United States between 1987 and 2002. OLT recipients with HBV were identified by the principal diagnosis of acute or chronic HBV or positive results on HBV markers. Patients were divided into Era 1 (1987-1991), Era 2 (1992-1996), and Era 3 (1997-2002). Era 1 consisted of 6,708 patients (675 with HBV), Era 2 consisted of 13,995 patients (1,005 with HBV), and Era 3 consisted of 20,730 patients (1,723 with HBV). More recent patients were older and had less advanced liver disease and shorter ischemic time. The survival of patients with HBV was significantly better for Era 2 than for Era 1 (P < .01) and for Era 3 than for Era 2 (P < .01). There was no difference in survival between patients with HBV and all other diagnoses for Era 3 (P = .14). In the multivariable analysis, the effect of these eras persisted when other variables such as recipient and donor age, warm ischemic time, pre-OLT disease severity, and hepatocellular carcinoma (HCC) were taken into account. Unlike previous reports, fulminant disease and Asian race had no effect on patient survival. In conclusion, these data underscore the effectiveness of therapeutic innovations that have occurred in the past two decades and indicate timely and widespread adoption of these measures by transplant centers nationwide. (Liver Transpl 2004;10:968-974.)
Rapid Ring‐Opening Polymerization of D,L‐Lactide by Microwaves
Authors: Zhang Chao , Liao Liqiong , Liu Lijian
Published: July 2004

Summary: Poly(D,L‐lactide) with a molar mass of 105 g · mol−1 and a yield over 90% was produced in 10 min by the ring‐opening polymerization of D,L‐lactide under microwave irradiation with forward power of 255 W. A degradation of the poly(D,L‐lactide) was also induced by microwaves with a power level over 340 W. The molar mass of poly(D,L‐lactide) was dependent upon the competition between the polymerization of D,L‐lactide and the degradation of the resulting polymer.

Profiles of molar mass versus microwave irradiation time (1.8 g DLLA, 0.1% Sn(Oct)2).

magnified image

Profiles of molar mass versus microwave irradiation time (1.8 g DLLA, 0.1% Sn(Oct)2).
Attachment of Polymer Films to Aluminium Surfaces by Photochemically Active Monolayers of Phosphonic Acids
Authors: Pahnke Jörg , Rühe Jürgen
Published: July 2004

Summary: We describe a simple photochemical process that allows the covalent attachment of a variety of different polymers at room temperature onto aluminium surfaces. The system is based on a photoreactive benzophenone derivative that is bound to aluminium surfaces by a phosphonic acid anchor. The synthesis of the phosphonic acid is described and the immobilization of this compound is studied by X‐ray photoelectron and FT‐IR spectroscopy. After deposition of the polymeric coating, UV light illumination at 365 nm, and solvent extraction of the substrate, polymer monolayers are obtained that are chemically bound to the surface.

Covalent attachment of polymers to the aluminium‐bound benzophenone phosphonic acid.

magnified image

Covalent attachment of polymers to the aluminium‐bound benzophenone phosphonic acid.
The Use of a Low‐Molar‐Mass Self‐Assembled Template to Direct the Crystallisation of Poly(ε‐caprolactone)
Authors: Siripitayananon Jintana , Wangsoub Supatra , Olley Robert H. , Mitchell Geoffrey R.
Published: July 2004

Summary: We show that small quantities of dibenzylidene sorbitol dispersed in poly(ε‐caprolactone) provide a self‐assembling nanoscale framework to yield high levels of crystal orientation. During modest shear flow of the melt, the additive forms highly extended nanoparticles which adopt a preferred alignment with respect to the flow field and, on cooling, polymer crystallisation is directed by these particles. We speculate that atomistic level epitaxy is unlikely to be the only directing influence.

SAXS pattern of PCL/DBS in the melt at 80 °C and subjected to a shear flow of 10 s−1 for 1 000 shear units. The flow direction is vertical.

magnified image

SAXS pattern of PCL/DBS in the melt at 80 °C and subjected to a shear flow of 10 s−1 for 1 000 shear units. The flow direction is vertical.
Nature of the Ring‐Banded Spherulites in Blends of Aromatic Poly(ether ketone)s
Authors: Chen Jian , Yang Decai
Published: July 2004

Summary: The ring‐banded spherulites in liquid crystalline poly(aryl ether ketone) (LC‐PAEK) and poly(aryl ether ether ketone) (PEEK) blends with a higher content (>50%) of LC‐PAEK are investigated by polarizing light microscopy (PLM) and atomic force microscopy (AFM) techniques. The results indicate that the light core and rings of the ring‐banded spherulites under PLM are mainly composed of an LC‐PAEK phase, while the dark rings consist of coexisting phases of PEEK and a small amount of LC‐PAEK. The formation of the ring‐banded spherulites is attributable to structural discontinuity caused by a rhythmic radial growth.

PLM image of ring‐banded spherulites in a 70:30 LC‐PAEK/PEEK blend caused by rhythmic growth.

magnified image

PLM image of ring‐banded spherulites in a 70:30 LC‐PAEK/PEEK blend caused by rhythmic growth.
Polymerization of Styrene in Cyclodextrin Channels: Can Confined Free‐Radical Polymerization Yield Stereoregular Polystyrene?
Authors: Uyar Tamer , Rusa Mariana , Tonelli Alan E.
Published: July 2004

Summary: Modeling of polystyrenes (PS) with various stereosequences in the narrow cylindrical channels corresponding to those found in γ‐cyclodextrin inclusion compounds (CD ICs) has been conducted. Based on the conformational modeling of stereoisomeric polystyrenes (PSs) in narrow channels, it was suggested that polystyrene with unusual microstructures might be produced by the constrained polymerization of styrene monomer in its γ‐CD‐IC crystals. The in‐situ polymerization of styrene inside the narrow channels of its γ‐CD‐IC crystals was performed in both organic and aqueous media. The 13C NMR spectrum of PS synthesized inside the γ‐CD channels in an aqueous medium shows some differences when compared to the 13C NMR spectrum of PS synthesized in toluene. These are presumably because of differences in their stereosequences. Here, we report our preliminary findings.

Schematic of cyclodextrin inclusion compound (CD‐IC) channels with included polymer guests.

magnified image

Schematic of cyclodextrin inclusion compound (CD‐IC) channels with included polymer guests.
Polybenzimidazoles for High Temperature Fuel Cell Applications
Authors: Kim Hyoung‐Juhn , An Seong Jin , Kim Ju‐Yong , Moon Jin Kyoung , Cho Sung Yong , Eun Yeong Chan , Yoon Hae‐Kwon , Park Youngmi , Kweon Ho‐Jin , Shin Eun‐Mi
Published: July 2004

Summary: Fuel cells were designed for high temperature operations. Poly[2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole] (PBI) was synthesized in a solution of P2O5, CH3SO3H, and CF3SO3H. The PBI was dissolved in a mixture of CF3CO2H and H3PO4 and the solution was used for the preparation of Pt catalyst slurry for membrane electrode assembly. The single cell showed a current density of 280 mA · cm−2 at a cell voltage of 0.5 V with feeds of H2 and O2 at 160 °C and without external humidification.

magnified image
Organically Modified Layered Titanate: A New Nanofiller to Improve the Performance of Biodegradable Polylactide
Authors: Hiroi Ryoichi , Ray Suprakas Sinha , Okamoto Masami , Shiroi Takashi
Published: July 2004

Summary: The preparation and characterization of a new type of nanocomposite material that is based on biodegradable polylactide (PLA) and organically modified layered titanate, is reported. Layered titanate, modified with a N‐(cocoalkyl)‐N,N‐[bis(2‐hydroxyethyl)]‐N‐methylammonium cation, was used as a new nanofiller (OHTO) for the nanocomposite preparation. Wide‐angle X‐ray diffraction and transmission electron microscopy (TEM) analyses confirmed that titanate layers were intercalated and nicely distributed in the PLA matrix. The materials properties of neat PLA improved remarkably after nanocomposite preparation.

UV/vis transmission spectra of neat PLA and a nanocomposite.

magnified image

UV/vis transmission spectra of neat PLA and a nanocomposite.
On the β Transition in High Density Polyethylene: the Effect of Transcrystallinity
Authors: Alon Yaara , Marom Gad
Published: July 2004

Summary: Transcrystallinity in UHMWPE fiber‐reinforced HDPE composites promotes a significant β transition that is untypical of high‐density polyethylene. Surface profiling by atomic force microscopy identifies two distinct morphologies in the composite without a boundary phase between them, which coincide with the transcrystalline layer and with the bulk spherulitic matrix. As a result, the claim that attributes this transition to loose chain folds at the lamella surface is favored.

Atomic force microscopy scan of the transcrystalline layer above the fiber with the impression of the fiber in the center.

magnified image

Atomic force microscopy scan of the transcrystalline layer above the fiber with the impression of the fiber in the center.
Quantification of vessel wall motion and cyclic strain using cine phase contrast MRI: In vivo validation in the porcine aorta
Authors: Draney Mary T. , Arko Frank R. , Alley Marcus T. , Markl Michael , Herfkens Robert J. , Pelc Norbert J. , Zarins Christopher K. , Taylor Charles A.
Published: July 2004

Artery wall motion and strain play important roles in vascular remodeling and may be important in the pathogenesis of vascular disease. In vivo observations of circumferentially nonuniform wall motion in the human aorta suggest that nonuniform strain may contribute to the localization of vascular pathology. A velocity‐based method to investigate circumferential strain variations was previously developed and validated in vitro; the current study was undertaken to determine whether accurate displacement and strain fields can be calculated from velocity data acquired in vivo. Wall velocities in the porcine thoracic aorta were quantified with PC‐MRI and an implanted coil and were then time‐integrated to compute wall displacement trajectories and cyclic strain. Displacement trajectories were consistent with observed aortic wall motion and with the displacements of markers in the aortic wall. The mean difference between velocity‐based and marker‐based trajectory points was 0.1 mm, relative to an average pixel size of 0.4 mm. Propagation of error analyses based on the precision of the computed displacements were used to demonstrate that 10% strain results in a standard deviation of 3.6%. This study demonstrates that it is feasible to accurately quantify strain from low wall velocities in vivo and that the porcine thoracic aorta does not deform uniformly. Magn Reson Med 52:286–295, 2004. © 2004 Wiley‐Liss, Inc.
Simultaneous measurement of arterial input function and tumor pharmacokinetics in mice by dynamic contrast enhanced imaging: Effects of transcytolemmal water exchange
Authors: Zhou Rong , Pickup Stephen , Yankeelov Thomas E. , Springer Charles S. , Glickson Jerry D.
Published: July 2004

A noninvasive technique for simultaneous measurement of the arterial input function (AIF) for gadodiamide (Omniscan) and its uptake in tumor was demonstrated in mice. Implantation of a tumor at a suitable location enabled its visualization in a cardiac short axis image. Sets of gated, low‐resolution saturation recovery images were acquired from each of five tumor‐bearing mice following intravenous administration of a bolus of contrast agent (CA). The AIF was extracted from the signal intensity changes in left ventricular blood using literature values of the CA relaxivity and a precontrast T1 map. The time‐dependent 1H2O relaxation rate constant (R1 = 1/T1) in the tumor was modeled using the BOLus Enhanced Relaxation Overview (BOLERO) method in two modes regarding the equilibrium transcytolemmal water exchange system: 1) constraining it exclusively to the fast exchange limit (FXL) (the conventional assumption), and 2) allowing its transient departure from FXL and access to the fast exchange regime (FXR), thus designated FXL/FXR. The FXL/FXR analysis yielded better fittings than the FXL‐constrained analysis for data from the tumor rims, whereas the results based on the two modes were indistinguishable for data from the tumor cores. For the tumor rims, the values of Ktrans (the rate constant for CA transfer from the vasculature to the interstitium) and ve (volume fraction of the tissue extracellular and extravascular space) returned from FXL/FXR analysis are consistently greater than those from the FXL‐constrained analysis by a factor of 1.5 or more corresponding to a CA dose of 0.05 mmole/kg. Magn Reson Med 52:248–257, 2004. © 2004 Wiley‐Liss, Inc.
Long component time constant of 23Na T relaxation in healthy human brain
Authors: Bartha Robert , Menon Ravi S.
Published: July 2004

Signal intensity in 23Na images is altered in pathologic conditions such as ischemia and may provide information regarding tissue viability complementary to MR diffusion and perfusion imaging. However, the multicomponent transverse relaxation of 23Na (spin 3/2) complicates the determination of tissue sodium concentration from 23Na images with nonzero echo‐time. The purpose of this study was to measure the long component time constant of tissue sodium T relaxation in the healthy human brain at 4 T. Multiecho gradient‐echo 23Na images (10 echo‐times ranging from 3.8–68.7 ms) were acquired in five healthy human volunteers. T was quantified on a pixel‐by‐pixel basis using a nonnegative least squares fitting routine using 100 equally spaced bins between 0.5–99.5 ms and parametric maps were produced representing components between 0.5–3, 3.1–50, 50.1–98, and 98.1–99.5 ms. The long T component of tissue sodium (average ± standard deviation) varied between cortex (occipital = 22.0 ± 2.4 ms), white matter (parietal = 18.2 ± 1.9 ms), and subcortical gray matter (thalamus = 16.9 ± 2.4 ms). These results demonstrate considerable regional variability and establish a foundation for future characterization of 23Na T in conditions such as cerebral ischemia and cancer. Magn Reson Med 52:407–410, 2004. © 2004 Wiley‐Liss, Inc.
Breath‐hold water and fat imaging using a dual‐echo two‐point dixon technique with an efficient and robust phase‐correction algorithm
Authors: Ma Jingfei
Published: July 2004

A two‐point Dixon technique using a novel phase‐correction algorithm and commercially available dual‐echo fast gradient‐echo pulse sequence is presented. The phase‐correction algorithm determines the directional rather than phase distribution of signals due to field inhomogeneities. Specifically, a region‐growing scheme uses precalculated spatial gradients of the signal phase to guide the growth sequence, so there is no need to manually select the seeds or use an empirical angular threshold. Further, the determination of the signal direction of a given pixel is based on both the amplitude and phase of the surrounding pixels, the direction of which has already been determined. The advantages of this algorithm include its easy implementation, computational efficiency, and robustness in the presence of pixels with large phase uncertainty. The feasibility and usefulness of the technique are demonstrated in vivo with artifact‐free water and fat images of an entire abdomen in a single breath‐hold. Magn Reson Med 52:415–419, 2004. © 2004 Wiley‐Liss, Inc.
Assessment of tumor blood perfusion by high‐resolution dynamic contrast‐enhanced MRI: A preclinical study of human melanoma xenografts
Authors: Benjaminsen Ilana C. , Graff Bjørn A. , Brurberg Kjetil G. , Rofstad Einar K.
Published: July 2004

A noninvasive method to obtain high‐resolution images of tumor blood perfusion is needed for individualized cancer treatments. In this study we investigated the potential usefulness of dynamic contrast‐enhanced MRI (DCE‐MRI), using human melanoma xenografts as models of human cancer. Gadopentetate dimeglumine (Gd‐DTPA) was used as the contrast agent, and DCE‐MRI was performed at a voxel size of 0.5 × 0.2 × 2.0 mm3 with spoiled gradient‐recalled sequences. We obtained images of E · F (where E is the extraction fraction, and F is perfusion) by subjecting DCE‐MR images to Kety analysis. We obtained highly reproducible E · F images, which we verified by imaging heterogeneous tumors twice. We hypothesized that the extraction fraction of Gd‐DTPA would be high and would not vary significantly in tumor tissue, implying that E · F should be a well‐suited parameter for describing tumor blood perfusion. Observations consistent with this hypothesis were made by comparison of E · F‐images with immunostained histological preparations from the imaged sections. The E · F images mirrored the histological appearance of the tumor tissue perfectly. Quantitative studies showed that E · F was highest in nonhypoxic tissue with high microvascular density, second highest in nonhypoxic tissue with low microvascular density, third highest in hypoxic tissue, and lowest in necrotic tissue. Moreover, the radial heterogeneity in E · F was almost identical to that in the blood supply, as assessed by the use of Na99mTcO4 as a perfusion tracer. Taken together, our observations show that high‐resolution images reflecting tumor blood perfusion can be obtained by DCE‐MRI. Magn Reson Med 52:269–276, 2004. © 2004 Wiley‐Liss, Inc.
Self‐navigated motion correction using moments of spatial projections in radial MRI
Authors: Welch Edward Brian , Rossman Phillip J. , Felmlee Joel P. , Manduca Armando
Published: July 2004

Interest in radial MRI (also known as projection reconstruction (PR) MRI) has increased recently for uses such as fast scanning and undersampled acquisitions. Additionally, PR acquisitions offer intrinsic advantages over standard two‐dimensional Fourier transform (2DFT) imaging with respect to motion of the imaged object. It is well known that aligning each spatial domain projection's center of mass (calculated using the 0th and 1st moments) to the center of the field of view (FOV) corrects shifts caused by in‐plane translation. In this work, a previously unrealized ability to determine the in‐plane rotational motion of an imaged object using the 2nd moments of the spatial domain projections in conjunction with a specific projection angle acquisition time order is reported. We performed the correction using only the PR data itself acquired with the newly proposed projection angle acquisition time order. With the proposed view angle acquisition order, the acquisition is “self‐navigating” with respect to both in‐plane translation and rotation. We reconstructed the images using the aligned projections and detected acquisition angles to significantly reduce image artifacts due to such motion. The theory of the correction technique is described, and its effectiveness is demonstrated in phantom and in vivo experiments. Magn Reson Med 52:337–345, 2004. © 2004 Wiley‐Liss, Inc.
Echo‐planar BOLD fMRI of mice on a narrow‐bore 9.4 T magnet
Authors: Nair Govind , Duong Timothy Q.
Published: July 2004

The feasibility of BOLD fMRI in association with electrical somatosensory stimulation on spontaneously breathing, isoflurane‐anesthetized mice was investigated using spin‐echo, echo‐planar imaging (EPI) on a vertical narrow‐bore 9.4 T magnet. Three experiments were performed to derive an optimal fMRI protocol. In Experiment 1 (n = 9), spin‐echo BOLD responses to 10% CO2 challenge under graded isoflurane (0.25–1.25%) ranged from 10 ± 2% to 3.5 ± 0.9%; the optimal BOLD contrast‐to‐noise ratio peaked at 0.75% isoflurane. In Experiment 2 (n = 6), hindpaw somatosensory stimulations using 1–7 mA under 0.75% isoflurane revealed the optimal BOLD response was at 6 mA. In Experiment 3 (n = 5), BOLD responses to 4 and 6 mA stimulation under 0.75% and 1% isoflurane were evaluated in detail, confirming the optimal conditions in Experiment 2. These results demonstrated that BOLD fMRI using single‐shot, spin‐echo EPI in a mouse somatosensory stimulation model could be routinely performed on high‐field, vertical, narrow‐bore magnets. This protocol might prove useful for fMRI studies of transgenic mice. Magn Reson Med 52:430–434, 2004. © 2004 Wiley‐Liss, Inc.
Rapid T2 estimation with phase‐cycled variable nutation steady‐state free precession
Authors: Deoni Sean C.L. , Ward Heidi A. , Peters Terry M. , Rutt Brian K.
Published: July 2004

Variable nutation SSFP (DESPOT2) permits rapid, high‐resolution determination of the transverse (T2) relaxation constant. A limitation of DESPOT2, however, is the presence of T2 voids due to off‐resonance banding artifacts associated with SSFP images. These artifacts typically occur in images acquired with long repetition times (TR) in the presence of B0 inhomogeneities, or near areas of magnetic susceptibility difference, such that the transverse magnetization experiences a net phase shift during the TR interval. This places constraints on the maximum spatial resolution that can be achieved without artifact. Here, a novel implementation of DESPOT2 is presented incorporating RF phase‐cycling which acts to shift the spatial location of the bands, allowing reconstruction of a single, reduced artifact‐image. The method is demonstrated in vivo with the acquisition of a 0.34 mm3 isotropic resolution T2 map of the brain with high precision and accuracy and significantly reduced artifact. Magn Reson Med 52:435–439, 2004. © 2004 Wiley‐Liss, Inc.
Prebolus quantitative MR heart perfusion imaging
Authors: Köstler Herbert , Ritter Christian , Lipp Michael , Beer Meinrad , Hahn Dietbert , Sandstede Jörn
Published: July 2004

The purpose of this study was to present the prebolus technique for quantitative multislice myocardial perfusion imaging. In quantitative MR perfusion studies the maximum contrast agent dose is limited by the requirement to determine the arterial input function (AIF). The prebolus technique consists of two consecutive contrast agent administrations. The AIF is determined from a first low‐dose bolus, while a second, high‐dose bolus allows the measurement of the myocardium with improved signal increase. The results of the prebolus technique using a multislice saturation recovery trueFISP sequence in healthy volunteers are presented. In comparison to a standard dose of 3 ml Gd‐DTPA, perfusion values are maintained while the signal increase in the concentration time courses was considerably improved, accompanied by reduced standard deviations of the obtained perfusion values (0.72 ± 0.13 ml/g/min for 1 ml/8 ml and 0.67 ± 0.10 ml/g/min for 1 ml/12 ml Gd‐DTPA, respectively). Magn Reson Med 52:296–299, 2004. © 2004 Wiley‐Liss, Inc.
Microcirculation and microvasculature in breast tumors: Pharmacokinetic analysis of dynamic MR image series
Authors: Brix Gunnar , Kiessling Fabian , Lucht Robert , Darai Susanne , Wasser Klaus , Delorme Stefan , Griebel Jürgen
Published: July 2004

The purpose of this study was to quantify microcirculation and microvasculature in breast lesions by pharmacokinetic analysis of Gd‐DTPA‐enhanced MRI series. StronglyT1‐weighted MR images were acquired in 18 patients with breast lesions using a saturation‐recovery‐TurboFLASH sequence. Concentration‐time courses were determined for blood, pectoral muscle, and breast masses and subsequently analyzed by a two‐compartment model to estimate plasma flow and the capillary transfer coefficient per unit of plasma volume (F/VP,KPS/VP) as well as fractional volumes of the plasma and interstitial space (fP,fI). Tissue parameters determined for pectoral muscle (fP= 0.04 ± 0.01,fI= 0.09 ± 0.01,F/VP= 2.4 ± 1.3 min‐1, andKPS/VP= 1.2 ± 0.5 min‐1) and 10 histologically proven carcinomas (fP= 0.20 ± 0.07,fI= 0.34 ± 0.16,F/VP= 2.4 ± 0.7 min‐1, andKPS/VP= 0.86 ± 0.62 min‐1) agreed reasonable well with literature data. Best separation between malignant and benign lesions was obtained by the ratioKPS/F(0.35 ± 0.17 vs. 1.23 ± 0.65). The functional imaging technique presented appears promising to quantitatively characterize tumor pathophysiology. Its impact on diagnosis and therapy management of breast tumors, however, has to be evaluated in larger patient studies. Magn Reson Med 52:420–429, 2004. © 2004 Wiley‐Liss, Inc.
Non‐Fourier‐encoded parallel MRI using multiple receiver coils
Authors: Mitsouras Dimitris , Hoge W. Scott , Rybicki Frank J. , Kyriakos Walid E. , Edelman Alan , Zientara Gary P.
Published: July 2004

This paper describes a general theoretical framework that combines non‐Fourier (NF) spatially‐encoded MRI with multichannel acquisition parallel MRI. The two spatial‐encoding mechanisms are physically and analytically separable, which allows NF encoding to be expressed as complementary to the inherent encoding imposed by RF receiver coil sensitivities. Consequently, the number of NF spatial‐encoding steps necessary to fully encode an FOV is reduced. Furthermore, by casting the FOV reduction of parallel imaging techniques as a dimensionality reduction of the k‐space that is NF‐encoded, one can obtain a speed‐up of each digital NF spatial excitation in addition to accelerated imaging. Images acquired at speed‐up factors of 2× to 8× with a four‐element RF receiver coil array demonstrate the utility of this framework and the efficiency afforded by it. Magn Reson Med 52:321–328, 2004. © 2004 Wiley‐Liss, Inc.
Imaging of myocardial infarction for diagnosis and intervention using real‐time interactive MRI without ECG‐gating or breath‐holding
Authors: Guttman Michael A. , Dick Alexander J. , Raman Venkatesh K. , Arai Andrew E. , Lederman Robert J. , McVeigh Elliot R.
Published: July 2004

Current methods for MRI of infarcted myocardium require ECG‐gating and breath‐holding during contrast‐enhanced segmented k‐space inversion‐recovery (IR) imaging. However, ECG‐gating can be problematic in MRI, and breath‐holding can be difficult for some patients. This work demonstrates that infarcted tissue can be visualized without ECG‐gating or breath‐holding with the use of intermittent inversion pulses during real‐time (RT) interactive imaging with steady‐state free precession (SSFP). The sequence generates a RT image stream containing a myocardium‐nulled image every few frames, which allows nearly simultaneous observation of both infarcted regions and wall motion. First‐pass perfusion and wall motion can be simultaneously observed with minor parameter modifications. This method may reduce diagnostic scan time, expand the target population, improve patient comfort, and facilitate targeted, interventional treatment of infarcted myocardium. Supplementary material for this article can be found on the MRM website at http://www.interscience.wiley.com/jpages/0740‐3194/suppmat/index.html.Magn Reson Med 52:354–361, 2004. Published 2004 Wiley‐Liss, Inc.
MOCVD as a dry deposition method of ZnSe buffers for Cu(In,Ga)(S,Se)2 solar cells
Authors: Siebentritt Susanne , Walk Philipp , Fiedeler Ulrich , Lauermann Iver , Rahne Kari , Lux‐Steiner Martha Ch. , Niesen Thomas P. , Karg Franz
Published: July 2004

ZnSe prepared by metal organic chemical vapor deposition is used as a buffer layer in Cu(In,Ga)(S,Se)2 solar cells without any utilization of wet chemistry. Cell efficiencies are as good as cells with the conventional CdS buffer. Stability of unencapsulated cells under damp heat conditions is somewhat lower for the alternative buffer. The first stages of photoassisted growth are studied. X‐ray photoemission spectroscopy shows that a continuous layer is formed. Copyright © 2004 John Wiley & Sons, Ltd.
Spatially resolved evaluation of power losses in industrial solar cells by illuminated lock‐in thermography
Authors: Isenberg Joerg , Warta Wilhelm
Published: July 2004

The principles of a recently introduced measurement technique for power losses in solar cells, illuminated lock‐in thermography (ILT), are reviewed. The main advantage of ILT over dark lock‐in Thermography (DLT) is measurement under realistic operational conditions of solar cells. The main focus of this paper is to demonstrate the wide range of applications of ILT in identifying the causes of power losses in solar cells. For this purpose different evaluation methods are presented. A method for the evaluation of improvement potentials within a given cell technology is demonstrated. It is shown that different types of series resistance may be localized. Small areas of recombination losses (e.g., grain boundaries) can routinely be detected, which is not possible in dark lock‐in thermography. Good correspondence with light‐beam‐induced current images is found. A realistic evaluation of the impact of recombination losses on solar cell performance is demonstrated on two examples. Finally, process‐ or treatment‐induced recombination losses are investigated. In summary ILT is shown to be an extremely powerful tool in localizing, identifying and quantifying power losses of solar cells under realistic illumination conditions. Copyright © 2004 John Wiley & Sons, Ltd.
A method for the rapid depletion of albumin and immunoglobulin from human plasma
Authors: Greenough Carrie , Jenkins Rosalind E. , Kitteringham Neil R. , Pirmohamed Munir , Park B. Kevin , Pennington Stephen R.
Published: July 2004

In studies of the plasma proteome, the high abundance of proteins such as albumin and immunoglobulin impedes the investigation of lower abundance proteins that may be more suitable as biomarkers of disease. We report the specific removal of 98% of albumin and 80% of immunoglobulin heavy chain from human plasma by affinity chromatography, and the subsequent improvement in the number of spots detected and their resolution following two‐dimensional gel electrophoresis.
Proteome analysis of human mesothelial cells during epithelial to mesenchymal transitions induced by shed menstrual effluent
Authors: Demir Ayşe Y. , Demol Hans , Puype Magda , de Goeij Anton F. P. M. , Dunselman Gerard A. J. , Herrler Andreas , Evers Johannes L. H. , Vandekerckhove Joël , Groothuis Patrick G.
Published: July 2004

Peritoneal endometriosis is the result of ectopic implantation and growth of endometrium tissue that has been regurgitated into the abdominal cavity during menstruation. We have previously shown that menstrual effluent induces epithelial to mesenchymal transitions (EMT) in mesothelial cells, which results in cell retraction and exposure of submesothelial extracellular matrix. Since endometrial tissue preferentially adheres to the extracellular matrix, adhesion of endometrial tissue to the peritoneum is facilitated. The EMT were shown to be associated with differential expression and phosphorylation of mesothelial proteins. Using radiolabeling and proteomics we detected changes in protein expression and phosphorylation that occur in mesothelial cells during the EMT process. The identity of 73 proteins, which were obtained from 324 analyzed spots, was confirmed. The expression of 35 proteins involved in organization of the cytoskeleton, signal transduction, regulation of the redox state, and production of ATP, was altered during the EMT process. Four of the identified proteins were differentially phosphorylated: annexin‐1, an actin‐binding protein and a substrate for receptor tyrosine kinases; tropomyosin‐α, a regulator of actin filament stability and cell shape; elongation factor 1 delta; ATP synthase β‐chain. In conclusion, factors from menstrual effluent induce specific changes in the expression and phosphorylation status of structural, regulatory and metabolic proteins relevant to the complex process of EMT in mesothelial cells.