bluuebunny/crossref_metadata_2025 huggingface dataset:
On‐column capillary electrophoretic monitoring of rapid reaction kinetics for determination of the antioxidative potential of various bioactive phenols
Authors: Vaher Merike , Ehala Sille , Kaljurand Mihkel
Published: February 2005

An on‐column capillary electrophoretic procedure for the determination of the antioxidative potential of various bioactive phenols, found in plant, fruit, and vegetable extracts, is described. The assay is based on a rapid mixing of phenols or phenolic extracts before the capillary, followed by pressurized injection of the reaction mixture into the capillary. After incubation of the reaction mixture inside the capillary, high voltage is switched on and separation of reactants and products is performed. Using hydrogen peroxide as a stressor, the kinetics of the oxidation of various bioactive phenols was studied (rutin, chlorogenic acid, quercetin, caffeic acid, gallic acid, and combinations of these) and compared with the oxidation rate of L‐ascorbic acid as a reference. The concept was demonstrated for the determination of the antioxidative potential of various polyphenol mixtures and of the methanol extract of the sea buckthorn (Hippophaë rhamnoides L.). In most cases quercetin has the highest rate constant of oxidation among the tested phenolic compounds. However, in the mixture L‐ascorbic acid/quercetin, the oxidation rate of L‐ascorbic acid was enhanced and oxidation of quercetin was strongly inhibited compared with the other combinations of tested polyphenols.
Comparison of microemulsion electrokinetic chromatography and micellar electrokinetic chromatography as methods for the analysis of ten benzophenones
Authors: Huang Hsi‐Ya , Chiu Chen‐Wen , Chen Yen‐Chen , Yeh Jui‐Ming
Published: February 2005

Microemulsion electrokinetic chromatography (MEEKC) and micellar electrokinetic chromatograpy (MEKC) were compared for their abilities to separate and detect ten similar benzophenones, which are commonly used as UV filters in various plastic and cosmetic products. Sodium dodecyl sulfate (SDS) concentration and column temperature rarely affected separation resolution for MEEKC, but separation of benzophenones could be improved by changing the SDS concentration and column temperature for MEKC. Buffer pH and ethanol (organic modifier) were found to markedly influence the separation selectivity for both MEEKC and MEKC systems. In addition, a higher electric voltage improved the separation efficiency without a noticeable reduction in separation resolution for MEEKC, whereas it caused a poor separation resolution for the MEKC system.
Electrokinetic capillary chromatography in a polar continuous‐phase water‐in‐oil microemulsion constituted by water, sodium dodecyl sulfate, and n‐pentanol
Authors: Mendonça Carla R. B. , Bica Clara I. D. , Piatnicki Clarisse M. S. , Simó‐Alfonso Ernesto F. , Ramis‐Ramos Guillermo
Published: February 2005

A water‐in‐oil (w/o) microemulsion (ME) constituted by 15% Tris buffer, pH 8.4, in water and 85% sodium dodecyl sulfate (SDS)/n‐pentanol 1:4 mixture, capable of dissolving up to 30% vegetable oils and lard, was used as background electrolyte in reverse microemulsion electrokinetic capillary chromatography (RMEEKC). Owing to the free SDS ions in the continuous phase and some degree of percolation, the ME showed a high conductivity (0.65 mS· cm‐1 at 25°C) and sustained a very stable capillary current. Previous rinsing of the capillary with a quaternary ammonium salt for electroosmotic flow (EOF) reduction, a series of nonionic and anionic solutes dissolved either in the ME or in fat samples diluted with the ME (1:4 ratio), were injected. Using −20 kV, fair separations of the solutes in the migration time order singly charged anions < nonionic solutes < doubly charged anions ∼ pyromellitate were obtained, salicylate (I) showing by far the shortest migration time, and phthalate (II) and pyromellitate the longest. Separation was attributed to partition between the aqueous droplets, where pyromellitate and II were assumed to be trapped, and the n‐pentanol continuous phase, where the mobilitites could be also modified by association of the solutes with SDS ions. Adequate EOF markers were not found, thus the relative mobility of any solute with respect to the mobility of the droplets, μr, was expressed as a fraction of the mobility of I with respect to that of the droplets, being μr = (tII − tR) tI / [(tII − tI) tR], where tR, tI, and tII are the migration times of the solutes I and II, respectively. The application of RMEEKC to the analysis of both hydrophilic and hydrophobic samples, including edible fats, was demonstrated.
Rapid assessment of β‐asarone content of Acorus calamus by micellar electrokinetic capillary chromatography
Authors: Hanson Kim M. , Gayton‐Ely Melissa , Holland Lisa A. , Zehr Peter S. , Söderberg Björn C. G.
Published: February 2005

This report outlines a rapid, reproducible method for the determination of β‐asarone, a known carcinogen, using micellar electrokinetic capillary chromatography (MEKC)‐UV‐vis absorbance and a simple alcohol extraction. The MEKC method is based on a running buffer comprised of 100 mM sodium dodecyl sulfate (SDS), pH 10. The method is reproducible and provides baseline separation of α‐asarone and β‐asarone. This protocol was used to determine the β‐asarone content of Acorus calamus rhizome of a diploid variety harvested from the wetlands of the United States and the triploid variety from India obtained commercially. The results indicate raw product that originated from India contained 4.4% w/w β‐asarone, while that from the United States contained 0.2% w/w β‐asarone. Neither sample contained detectable concentrations of α‐asarone. This is the first report of the use of MEKC to determine asarone in a natural source.
Determination of ceftazidime in plasma and cerebrospinal fluid by micellar electrokinetic chromatography with direct sample injection
Authors: Yeh Hsin‐Hua , Yang Yuan‐Han , Chou Yu‐Wei , Ko Ju‐Yun , Chou Chia‐An , Chen Su‐Hwei
Published: February 2005

A simple micellar electrokinetic chromatography (MEKC) with UV detection at 254 nm for analysis of ceftazidime in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of ceftazidime from biological matrix was performed at 25°C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Several parameters affecting the separation of the drug from biological matrix were studied, including pH and concentration of the Tris buffer and SDS. Using cefazolin as an internal standard (IS), the linear ranges of the method for the determination of ceftazidime in plasma and in CSF were all over the range of 3–90 μg/mL; the detection limit of the drug in plasma and in CSF (signal‐to‐noise ratio = 3; injection 0.5 psi, 5 s) was 2.0 μg/mL. The applicability of the proposed method for determination of ceftazidime in plasma and CSF collected after intravenous administration of 2 g ceftazidime in patients with meningitis was demonstrated.
Separation strategy for acidic chiral pharmaceuticals with capillary electrochromatography on polysaccharide stationary phases
Authors: Mangelings Debby , Tanret Indiana , Matthijs Nele , Maftouh Mohamed , Massart D. Luc , Vander Heyden Yvan
Published: February 2005

The effect of five factors on the capillary electrochromatographic enantioseparation of acidic compounds was studied using an experimental design. The studied factors were pH, acetonitrile content in the mobile phase, temperature, buffer concentration, and applied voltage. These experiments allowed defining a generic separation strategy applicable on acidic compounds with chemical and structural diversity. The starting screening conditions consist of a 45 mM ammonium formate electrolyte at pH 2.9 mixed with 65% acetonitrile, an applied voltage of 15 kV, and a temperature of 25°C. The screening phase occasionally can be followed by an optimization procedure. Evaluation of the proposed strategy pointed out that it allows achieving baseline resolution within a relatively short time when a beginning of separation is obtained at the starting conditions. This strategy revealed enantioselectivity for 11 compounds out of 15, of which 10 could be baseline‐separated after the proposed optimization steps.
Recent advances in micellar electrokinetic chromatography
Authors: Pappas Theron J. , Gayton‐Ely Melissa , Holland Lisa A.
Published: February 2005

This review contains nearly 200 reference citations, and covers advances in electrokinetic capillary chromatography based on micelles, including stabilized micelle complexes, polymeric and mixed micelles from 2003–2004. Detection strategies, analyte determinations, and applications in micellar electrokinetic capillary chromatography (MEKC) are discussed. Information regarding methods of analyte concentration, analyte specific analyses, and nonstandard micelles has been summarized in tabular form to provide a means of rapid access to information pertinent to the reader.
Conformational effects on the performance and selectivity of a polymeric pseudostationary phase in electrokinetic chromatography
Authors: McCarney Jonathan P. , Loflin Robert D. , Rauk Erika , Yusa Shin‐Ichi , Palmer Christopher P.
Published: February 2005

The effect of the conformation of a polymeric pseudostationary phase on performance and selectivity in electrokinetic chromatography was studied using an amphiphilic pH‐responsive polymer that forms compact intramolecular aggregates (unimer micelles) at low pH and a more open conformation at high pH. The change in conformation was found to affect the electrophoretic mobility, retention, selectivity, and separation efficiency. The low‐pH conformer has higher electrophoretic mobility and greater affinity for most solutes. The unimer micelle conformation was also found to provide a solvation environment more like that of micelles and other amphiphilic self‐associative polymers studied previously. It was not possible to fully characterize the effect of conformation on efficiency, but very hydrophobic solutes with long alkyl chains appeared to migrate with better efficiency when the unimer micelle conformation was employed. The results imply that polymers with a carefully optimized lipophilic‐hydrophilic balance that allow self‐association will perform better as pseudostationary phases. In addition, the results show that electrokinetic chromatography is a useful method for determining the changes in solvation environment provided by stimuli‐responsive polymers with changes in the conditions.
Analysis of antiepileptic drugs in biological fluids by means of electrokinetic chromatography
Authors: Pucci Vincenzo , Raggi Maria Augusta
Published: February 2005

An overview of the electrokinetic chromatographic methods for the analysis of antiepileptic drug levels in biological samples is presented. In particular, micellar electrokinetic capillary chromatography is a very suitable method for the determination of these drugs, because it allows a rapid, selective, and accurate analysis. In addition to the electrokinetic chromatographic studies on the determination of antiepileptic drugs, some information regarding sample pretreatment will also be reported: this is a critical step when the analysis of biological fluids is concerned. The electrokinetic chromatographic methods for the determination of recent antiepileptic drugs (e.g., lamotrigine, levetiracetam) and classical anticonvulsants (e.g., carbamazepine, phenytoin, ethosuximide, valproic acid) will be discussed in depth, and their pharmacological profiles will be briefly described as well.
Micellar electrokinetic chromatography of bilirubin, related compounds, and selected drugs with mixtures of binary bile salts
Authors: Olivares Juan , Conner Matthew J. , Vass Christa A. , Kurtin William. E. , Bushey Michelle M.
Published: February 2005

Micellar electrokinetic chromatography was used to study the behavior of quinine, propranolol, bilirubin, biliverdin dimethyl ester, and xanthobilirubin methyl ester in single and binary bile salt micelle systems comprised of glycocholic acid and glycodeoxycholic acid. Micelle systems studied had total bile salt concentrations in the range of 10–33 mM with molar ratios of 1:0, 2:1, 1:1, 1:2, and 0:1 glycocholic acid:glycodeoxycholic acid. A pH 8.5 phosphate‐borate buffer system was used. For all analytes except bilirubin, the smallest migration factors were found in glycocholic acid solutions and the largest in glycodeoxycholic acid solutions. Intermediate migration factors were found for all compounds except bilirubin in the binary bile salt systems. Bilirubin behaved uniquely with its largest migration factors in the binary bile salt mixtures.
Investigation of the stability of polyelectrolyte multilayer coatings in open‐tubular capillary electrochromatography using laser scanning confocal microscopy
Authors: Kapnissi‐Christodoulou Constantina P. , Lowry Mark , Agbaria Rezik A. , Geng Lei , Warner Isiah M.
Published: February 2005

A simple polyelectrolyte multilayer (PEM) coating procedure was used for the development of stable modified capillaries. PEM coatings were constructed in fused‐silica capillaries using alternating rinses of cationic and anionic polyelectrolytes. The multilayer coatings investigated in this study consisted of two and twenty layer pairs, or bilayers. A bilayer is one layer of a cationic polymer and one layer of an anionic polymer. Poly(diallyldimethylammonium chloride) was used as the cationic polymer, and the polymeric surfactant poly(sodium N‐undecanoyl‐L‐leucylvalinate) was used as the anionic polymer. Previous studies for both chiral and achiral separations have shown that PEM‐coated capillaries have excellent reproducibilities, remarkable endurance, and strong stabilities against extreme pH values when used in open‐tubular capillary electrochromatography (OT‐CEC). In this study, the stability of the coatings was further investigated after exposure to 0.1 M and 1.0 M NaOH. Structural changes of these coatings were monitored using laser scanning confocal microscopy (LSCM) after flushing the capillaries with NaOH. This technique allowed observation of the degradation of the coatings. Observations are discussed in terms of separations using OT‐CEC. Electropherograms obtained from the chiral separation of 1,1'‐binaphthyl‐2,2'‐dihydrogenphosphate in OT‐CEC showed a decrease in selectivity and an increase in electroosmotic mobility after long exposure to NaOH. The ability to recover the capillaries by exposure to NaOH was also demonstrated. Measurements of electroosmotic mobility and selectivity showed that 2‐bilayer and 20‐bilayer PEM coatings could be completely removed from the capillary surface after approximately 3.5 and 9.5 h, respectively, of continuous exposure to 1 M NaOH.
Lipid vesicles in capillary electrophoretic techniques: Characterization of structural properties and associated membrane‐molecule interactions
Authors: Owen Rebecca L. , Strasters Joost K. , Breyer Emelita D.
Published: February 2005

This paper reviews the use of lipid vesicles as model membranes in capillary electrophoresis (CE). The history and utility of CE in the characterization of microparticles is summarized, focusing on the application of colloidal electromigration theories to lipid vesicles. For instance, CE experiments have been used to characterize the size, surface properties, enclosed volumes, and electrophoretic mobilities of lipid vesicles and of lipoprotein particles. Several techniques involving small molecules or macromolecules separated in the presence of lipid vesicles are discussed. Interactions between the analytes and the lipid vesicles – acting as a pseudostationary phase or coated stationary phase in electrokinetic chromatography (EKC) – can be used to obtain additional information on the characteristics of the vesicles and analytes, and to study the biophysical properties of membrane‐molecule interactions in lipid vesicles and lipoproteins. Different methods of determining binding constants by EKC are reviewed, along with the relevant binding constant calculations and a discussion of the application and limitations of these techniques as they apply to lipid vesicle systems.
Capillary electrochromatography of caffeine and its metabolites in rat brain microdialysate
Authors: Ohyama Kaname , Wada Mitsuhiro , Lord Gwyn A. , Ohba Yoshihito , Nakashima Mihoko N. , Nakashima Kenichiro , Akiyama Shuzo , Lim Chang Kee , Kuroda Naotaka
Published: February 2005

A capillary electrochromatography (CEC) method has been developed for the separation of caffeine and its two metabolites 1‐methylxanthine (1‐MX) and 1,7‐dimethylxanthine (1,7‐DX). The stationary phase was 3‐(1,8‐naphthalimido) propyl‐modified silyl silica gel (NAIP) and the best separations were achieved with 4.0 mM citrate buffer (pH 5.0) containing 80% methanol at an applied voltage of 25 kV. The compounds were completely separated in less than 3.5 min with good repeatability, which was approximately 3‐times less than that in high‐performance liquid chromatography (HPLC) with NAIP. The proposed method coupled with microdialysis was successfully applied to the monitoring of caffeine concentration in rat brain with detection limits of 1.11 μg/mL.
Chiral ion‐exchange capillary electrochromatography of arylglycine amides with dextran sulfate as a pseudostationary phase
Authors: Chen Yi , Lu Xiaoning , Han Zhiqiang , Qi Li , Wang Mei Xiang , Yu Xiao , Yang Gengliang , Mao Lanqun , Ma Huiming
Published: February 2005

A low‐cost tunable chiral ion‐exchange capillary electrochromatographic method has been developed for the separation of arylglycine amide racemic mixtures with dextran sulfate (DS) as an anionic and chiral pseudostationary phase and Tris‐tartrate as a buffer system. The concentrations of DS and Tris had opposite influences on retention and resolution and could serve as ideal factors to finely tune the running speed and chiral resolution. Tartrate and pH largely impact the separation but pH should be confined within 3.0–5.5, only suitable for coarse tuning, while tartrate was preserved as the key buffering reagent, normally maintained at 40 mmol/L. With a working system composed of 0.1–1.0% DS, 20–60 mmol/L Tris, and 40 mmol/L tartrate at pH 3.50–4.50, the enantioresolution of arylglycine amides was shown to be dependent on their chemical structure: The chiral resolution increased when the hydrogen at the α‐amino group or at the p‐position of phenyl ring was replaced by other larger group(s) but the resolution decreased when the group at the o‐ or m‐site on the phenyl ring was enlarged. Further, the electronegative substitute of ‐Cl had larger resolution increment than methyl or methoxy at the position p‐ of phenyl ring but much lower increment at position m‐. It is possible to well explain the resolution variation phenomenon by considering the group resistance and the variation of hydrogen‐bonds formed inside the amino amides and between the solutes and DS. The amido group was shown irreplaceable to have chiral resolution with DS alone as an ionic and chiral pseudostationary phase.
Combining solid‐phase microextraction and on‐line preconcentration‐capillary electrophoresis for sensitive analysis of pesticides in foods
Authors: Hernández‐Borges Javier , Cifuentes Alejandro , García‐Montelongo Francisco J. , Rodríguez‐Delgado Miguel Á.
Published: February 2005

The combined use of solid‐phase microextraction (SPME) and different on‐line preconcentration strategies for ultrasensitive capillary electrophoresis‐ultraviolet (CE‐UV) analysis of five pesticides in a single run is investigated. Normal stacking mode (NSM), field‐enhanced sample injection (FESI), and stacking with matrix removal (SWMR) are explored to increase the sensitivity of the CE‐UV analysis of a selected group of pesticides (cyprodinil, cyromazine, pyrifenox, pirimicarb, and pyrimethanil). It could be observed that reverse polarity‐stacking with matrix removal (RP‐SWMR) provided the best results in terms of sensitivity (enhancement was up to 272‐fold compared with normal injection). The separation buffer consisted of 0.4 mM cetyltrimethylammonium chloride (CTAC), 0.4 M acetic acid at pH 4 containing 5% v / v 2‐propanol. This approach was then combined with SPME to determine the pesticides in water, apple, and orange juice. The combination of both preconcentration procedures allowed the determination of these pesticides at concentrations down to 2.5 μg / L in water and 3.1 μg / L in juices (i.e., levels well below the maximum residue limits allowed for these compounds). To our knowledge, this is the first report showing the great possibilities of the combined use of SPME, on‐line sample preconcentration, and CE for pesticide analysis.
Editorial: Electrophoresis 4‐5/2005
Authors: El Rassi Ziad
Published: February 2005

No abstracts.
Psychosocial factors involved in delayed consultation by patients with head and neck cancer
Authors: Rozniatowski Olivier , Reich Michel , Mallet Yann , Penel Nicolas , Fournier Charles , Lefebvre Jean‐Louis
Published: February 2005

Background.

In the north of France, a delay in primary consultation has been noted among patients with head and neck cancer. This group is often correlated with lower socioeconomic status and a lack of medical information. Therefore, the choice to seek consultation is often influenced by symptoms such as pain and change in the size of tumors in the neck. We studied this delay in seeking consultation, focusing on psychosocial variables such as professional and social background, the involvement of a spouse/partner, and the presence of anxiety and depression.

Methods.

Two rating scales were administered to 50 patients with large tumors (T3/T4) and 50 patients with small tumors (T1/T2), and the results were compared. These rating scales were as follows: (1) a 17‐item questionnaire assessing sociodemographic data, presenting symptoms, factors generating the consultation, and reasons for delay; and (2) the Hospital Anxiety and Depression Scale (HADS).

Results.

Both groups were predominantly male and working‐class. Significant differences were observed in time since symptom onset and in conscious delay in seeking medical attention. The group with large tumors was characterized by lower involvement of a spouse/partner, conscious delay before first consultation, greater social isolation, fewer medical visits, and lower HADS anxiety scores. The group with small tumors sought consultation sooner and was characterized by greater involvement of a spouse/partner, correlated with significant anxiety. Depression was not a factor influencing delay within either group.

Conclusions.

The interpersonal relationship with a spouse/partner seemed to be essential in the dynamics surrounding consultation. Anxiety, rather than socioeconomics status, was a discriminating factor in the delay in seeking consultation. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX, 2005
Metastatic head and neck carcinoma to a percutaneous endoscopic gastrostomy site
Authors: Adelson Robert Todd , Ducic Yadranko
Published: February 2005

Background.

Percutaneous endoscopic gastrostomy (PEG) tube placement is a safe and widely accepted alternate route for enteral alimentation in the head and neck cancer patient population. Cancer metastatic to a PEG tube exit site is a rare but serious complication of this procedure. We sought to determine the route of spread responsible for PEG site metastases such that we may prevent further occurrences of this highly morbid condition. We also report a case of PEG site metastasis at our institution.

Methods.

We performed a MEDLINE search for the years 1962 to 2002 and conducted a review of the literature. In the case at our institution, a 63‐year‐old man was referred to our institution with recurrent squamous cell carcinoma of the right base of tongue; he also had a 1.5‐cm left apical lung nodule. He underwent PEG tube placement at the time of staging panendoscopy. Six months after the original tube placement, he had an ulcerated mass develop at the PEG site; biopsy of the mass revealed squamous cell carcinoma histologically identical to the base of tongue tumor. He also had recurrent lung cancer and four hepatic lesions develop.

Results.

In our MEDLINE search, of the five patients diagnosed with PEG site disease >10 months after PEG placement, all five (100%) had synchronous distant metastatic disease. In the group of patients diagnosed with PEG site metastases ≤10 months after PEG placement, only four (24%) of 17 had synchronous distant metastatic disease. All patients underwent PEG placement by means of the “pull” technique. Direct implantation with a variable‐sized initial tumor burden can explain all cases of PEG site metastasis. The presence of distant metastases is representative of the natural history of advanced head and neck malignancies. Smaller initial tumor implants present later than would larger initial tumor burdens, when the patient is more likely to have distant metastatic disease. In the case at our institution, the patient did not respond to treatment for his hepatic and PEG site metastases and his lung cancer, and he died 4 months after detection of the PEG site metastasis.

Conclusions.

PEG site metastases are iatrogenic complications of PEG tube placement in patients with squamous cell carcinoma of the upper aerodigestive tract. The use of laparoscopic, open, or the “push” technique of PEG tube placement in patients with head and neck cancer may prevent direct implantation of malignant cells into an enteral access site. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX, 2005
Oncologic effectiveness of selective neck dissection in the N0 irradiated neck
Authors: Solares C. Arturo , Fritz Michael A. , Esclamado Ramon M.
Published: February 2005

Background.

The incidence and patterns of nodal spread in previously irradiated N0 necks are not well defined. Therefore, the safety and efficacy of selective neck dissection (SND) in this patient population is not well established. In a previous report from our institution, SND in irradiated patients with recurrent disease at the primary site but clinically negative necks resulted in excellent tumor control in the neck. The objective of this study is to validate our initial observations in a larger sample of patients with longer follow‐up.

Methods.

A retrospective chart analysis of patients previously treated with primary radiation therapy or chemoradiotherapy for squamous cell carcinoma (SCC) of the head and neck between January 1997 and June 2003 was performed. Patients with recurrent or persistent disease at the primary site or a second primary head and neck SCC, with no clinical or radiologic disease in the neck, who underwent surgical salvage with resection of the primary site along with a site‐specific SND were analyzed. Patients who remained disease free at the primary site were analyzed for regional control after SND.

Results.

Sixty‐nine patients underwent a total of 96 site‐specific SNDs. The mean age was 64.1 years (range, 39–91 years). There was histologically positive nodal disease in 17 of 69 patients (25%), and 22 of 96 necks (23%). Fifty‐three patients had at least a 12‐month follow‐up. The mean follow‐up was 23.3 months (range, 1–96 months). Of the patients with 1‐year of follow‐up, six patients died from recurrence at the primary site, and nine died from distant metastasis. There were no cases of neck recurrence with the primary site controlled. All patients who had more than two positive nodes had recurrence either at the primary site or distant metastasis.

Conclusions.

Our results confirm that the patterns of lymphatic spread are not affected by radiation. We conclude that SND is oncologically safe in the management of the N0 irradiated neck and that the finding of more than two positive nodes predicts a poor outcome. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX, 2005
Quality of life as predictor of weight loss in patients with head and neck cancer
Authors: Petruson Karin M. , Silander Ewa M. , Hammerlid Eva B.
Published: February 2005

Background.

The purpose of this prospective study was to evaluate whether a relationship exists between malnutrition (≥10% weight loss) and health‐related quality of life (HRQL) in patients with head and neck cancer and whether weight loss can be predicted with HRQL questionnaires.

Methods.

Weight and HRQL were monitored in 49 patients. HRQL was assessed longitudinally, using the European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ‐C30), the EORTC Head and Neck Cancer module (QLQ‐H&N35), and the Hospital Anxiety and Depression Scale (HADS).

Results.

At diagnosis, those patients who had a weight loss greater than 10% (n = 20) after treatment scored significantly worse on 15 of 28 HRQL variables than did patients who lost less (n = 29). The largest difference (Δ ≥20) was found for role functioning, fatigue, loss of appetite, global quality of life, sticky saliva, and swallowing. Differences in HRQL persisted even after 3 years. The fatigue scale was the only significant predictor of weight loss (p = .005) at diagnosis.

Conclusions.

Patients with head and neck cancer who are at risk of severe weight loss developing during treatment may be detected with the aid of HRQL questionnaires at diagnosis. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX,2005
Congenital intracranial frontotemporal dermoid cyst presenting as a cutaneous fistula
Authors: Scolozzi Paolo , Lombardi Tommaso , Jaques Bertrand
Published: February 2005

Background.

Intracranial extension and a cutaneous sinus tract are rarely seen with craniofacial dermoid cysts, with few cases reported in the literature.

Methods.

We report a case of a 1‐year‐old girl who was initially seen with a cutaneous fistula of the frontotemporal region, which revealed an intracranial dermoid cyst.

Results.

The patient underwent a right lateral orbitotomy by a bicoronal approach. The cyst was seated within the lateral orbital wall, with intracranial extension through the temporal and sphenoidal bones to the dura of the temporal lobe. Histopathologic analysis confirmed the diagnosis of a dermoid cyst.

Conclusions.

Craniofacial dermoid cysts may be associated with a cutaneous sinus tract and/or intracranial extension. Failure to recognize and promptly treat these lesions may lead to a progressive skeletal distortion and/or recurrent infection with a potential for meningitis or cerebral abscess. Therefore, detailed CT and MRI scans are mandatory before surgical treatment of any cutaneous fistula in the head and neck region. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX, 2005
Role of phosphorylated CaMKII and calcineurin in the differential effect of hypothyroidism on LTP of CA1 and dentate gyrus
Authors: Gerges N.Z. , Alzoubi K.H. , Alkadhi K.A.
Published: February 2005

Hypothyroidism impairs early long‐term potentiation (LTP) in the CA1 but not in the dentate gyrus (DG) of hippocampus of anesthetized adult rats. Protein levels and activities of signaling molecules in both the CA1 and DG of surgically thyroidectomized and sham‐operated euthyroid rats were measured. Basal levels of total calmodulin kinase II (CaMKII) protein in both the CA1 and DG were decreased in hypothyroidism. Marked reduction of basal P‐CaMKII levels and CaMKII activity was seen in CA1, but not in the DG of the same hypothyroid animals. Basal levels of calmodulin and protein kinase Cγ (PKCγ) were decreased in CA1 but remained unchanged in the DG of hypothyroid rats. Basal calcineurin levels and activity, although enhanced in CA1, were reduced in the DG of hypothyroid rats. These findings suggest that the DG may possess a compensatory mechanism whereby calcineurin levels are reduced, to allow sufficient CaMKII activity to produce an apparently normal LTP in hypothyroid rats. © 2005 Wiley‐Liss, Inc.
Preparation and characterization of novel tricalcium silicate bioceramics
Authors: Zhao Wenyuan , Chang Jiang
Published: February 2005

Novel tricalcium silicate (Ca3SiO5) ceramics were successfully fabricated. The mechanical properties of the ceramics were dependent remarkably on sintering temperature. The fracture toughness, Young's modules, and bending strength of Ca3SiO5 ceramics sintered at 1500°C were 1.93 MPa · m1/2, 36.7 GPa, and 93.4 MPa, respectively. These findings suggest that the Ca3SiO5 ceramics possess good mechanical properties, and might be a potential bone implant material. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 86–89, 2005
Biocompatibility of titanium implants modified by microarc oxidation and hydroxyapatite coating
Authors: Li Long‐Hao , Kim Hae‐Won , Lee Su‐Hee , Kong Young‐Min , Kim Hyoun‐Ee
Published: February 2005

A thin hydroxyapatite (HA) layer was coated on a microarc oxidized titanium (MAO‐Ti) substrate by means of the sol–gel method. The microarc oxidation (anodizing) enhanced the biocompatibility of the Ti, and the bioactivity was improved further by the sol–gel HA coating on the anodized Ti. The HA sol was aged fully to obtain a stable and phase‐pure HA, and the sol concentration was varied to alter the coating thickness. Through the sol–gel HA coating, the Ca and P concentrations in the coating layer increased significantly. However, the porous morphology and roughness of the MAO‐Ti was altered very little by the sol–gel treatment. The proliferation and alkaline phosphatase (ALP) activity of the osteoblast‐like cells on the MAO/HA sol–gel‐treated Ti were significantly higher than those on the MAO‐Ti without the HA sol–gel treatment. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 48–54, 2005
Adsorption of serum fetuin to hydroxylapatite does not contribute to osteoblast phenotype modifications
Authors: Xie Jianwei , Baumann Melissa J. , McCabe Laura R.
Published: February 2005

Osteoblasts exhibit enhanced differentiation and altered gene profiles when cultured on hydroxyapatite (HA) compared to plastic surfaces. To begin determining mechanisms for this response, we used proteomics to identify proteins predominantly found in osteoblasts on HA but not plastic surfaces. Two‐dimensional gel electrophoresis and Western analyses indicate that fetuin is abundant in extracts from HA, but not plastic surfaces. Incubation of HA and plastic surfaces with cell culture medium (containing 10% serum) under cell‐free conditions shows that fetuin is predominantly derived from the culture medium serum and readily adsorbs to the HA surface. However, we did detect low levels of fetuin B mRNA in osteoblasts. Serum albumin, actin‐β, apolipoprotein‐AI, and vimentin also adsorbed to HA. To determine the role of fetuin in the HA‐induced osteoblast phenotype changes, osteoblasts were seeded onto fetuin‐coated or uncoated HA under serum‐free conditions. Osteoblast morphology was similar on both HA surfaces, suggesting that HA alone (without adsorbed serum proteins) is sufficient for cell attachment and spreading. Similarly, genes previously reported to be modulated by HA (glvr‐1, DMP‐1, osteoglycin, and proliferin 3) were modulated even in the absence of fetuin or other serum proteins. These data show that HA surface can be enriched selectively with fetuin from serum; however, neither fetuin or other serum proteins are required to mediate HA‐induced osteoblast attachment, spreading, or changes in expression of genes examined. This finding suggests that factors intrinsic to HA are required for the response. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 39–47, 2005
Flow cytometric measurement of phagocytosis reveals a role for C3b in metal particle uptake by phagocytes
Authors: Baldwin L. , Flanagan B. F. , Hunt J. A.
Published: February 2005

A methodology for the quick and efficient study of phagocytosis has been developed. It uses the flow cytometer to exploit the change in size and granularity that occurs in cells upon the ingestion of particulate material. The numbers of cells that have phagocytosed particles can be calculated from the distinct shift in regions that occurs. The method also allows the factors governing phagocytosis to be studied in detail through the use of blocking agents or antibodies. Blood‐derived monocytes were studied to investigate the role of complement in metal particle phagocytosis to further understand aseptic loosening. Factor C3b was found to be fundamental to the opsonization and phagocytosis of metal particles by monocytes. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 80–85, 2005
Effect of particulate bioactive glasses on human macrophages and monocytes in vitro
Authors: Day Richard M. , Boccaccini Aldo R.
Published: February 2005

Bioactive glasses, originally developed to promote tissue adhesion, are finding an increasing array of biomedical applications. The aim of the current study was to assess the ability of silicate‐ and zinc phosphate‐based bioactive glasses to modulate the secretion of cytokines from activated human macrophages and monocytes. Human macrophages and monocytes were isolated and cultured on surfaces coated with a range of quantities of the bioactive glasses. Nontoxic concentrations of the glasses were selected and assessed further for their ability to modulate the secretion of tumor necrosis factor (TNF)‐α, interleukin (IL)‐10 and ‐6, in the presence or absence of the stimulant lipopolysaccharide. 45S5 glass produced a significant reduction to the amount of TNF‐α (p < 0.05) and IL‐6 (p < 0.01) secreted by stimulated cells compared with cells stimulated in the absence of bioactive glass. A significant reduction in IL‐6 secretion was also observed with the other silicate‐ and zinc phosphate‐based glasses tested. IL‐10 secretion was increased (but not significantly) in presence of all glasses tested. TNF‐α and IL‐6 secretion from stimulated cells was lower in presence of the silicate glasses compared with the zinc phosphate glasses, indicating that this system of bioactive glass might be of clinical use in conditions associated with inflammation. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 73–79, 2005
Metabolism of xanthohumol and isoxanthohumol, prenylated flavonoids from hops (Humulus lupulus L.), by human liver microsomes
Authors: Nikolic Dejan , Li Yongmei , Chadwick Lucas R. , Pauli Guido F. , van Breemen Richard B.
Published: February 2005

The female flowers of hops (Humulus lupulus L.) used to flavor beer contain the prenylated flavonoids xanthohumol (XN) and isoxanthohumol (IX). IX is moderately estrogenic in vitro and XN has pharmacological properties that might make it useful as a cancer chemopreventive agent. The metabolism of these dietary flavonoids was investigated in vitro using human liver microsomes. Hydroxylation of a prenyl methyl group was the primary route of oxidative metabolism forming either cis or trans hydroxylated metabolites of IX but only the trans isomer of XN. The double bond on the prenyl group of both compounds formed an epoxide which was opened by an intramolecular reaction with the neighboring hydroxyl group. The potent phytoestrogen 8‐prenylnaringenin (8‐PN) was detected as a demethylation product of IX. However, the analogous demethylation reaction was not observed for XN. Since XN can be converted to IX through acid‐catalyzed cyclization in the stomach, XN might contribute to the in vivo levels of estrogenic 8‐PN following consumption of hops extracts. Copyright © 2005 John Wiley & Sons, Ltd.
Liquid chromatography/electrospray tandem mass spectrometry of terpenoid lactones in Ginkgo biloba
Authors: Sun Yongkai , Li Wenkui , Fitzloff John F. , van Breemen Richard B.
Published: February 2005

Ginkgo biloba (ginkgo) is one of most frequently used botanical dietary supplements. The bioactive constituents include the terpenoid lactones consisting of bilobalide and the ginkgolides A, B, C and J. A new assay based on high‐performance liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) was developed for the measurement of the terpenoid lactones in ginkgo products such as leaf powder and extracts. Initially, the MS/MS fragmentation pathways of ginkgolides were investigated to identify abundant fragment ions that might be useful for the sensitive and selective detection of ginkgolides and bilobalide during LC/MS/MS. Then, sample preparation and clean‐up procedures were streamlined to maximize throughput by taking advantage of the selectivity of LC/MS/MS detection. Analyte recoveries exceeded 90%, the intra‐assay and inter‐assay relative standard deviations were <5%, the relative error was <8% and the limits of detection and quantification were 3.6–120 and 11–350 fmol, depending on the analyte that was injected on to the LC column. Therefore, this LC/MS/MS assay facilitated the rapid quantitative analysis of ginkgolides A, B, C and J and bilobalide in ginkgo dietary supplements with excellent recovery, reproducibity, accuracy and sensitivity. Copyright © 2005 John Wiley & Sons, Ltd.
Mass spectrometric determination of selenenylsulfide linkages in rat selenoprotein P
Authors: Ma Shuguang , Hill Kristina E. , Burk Raymond F. , Caprioli Richard M.
Published: February 2005

The reversible formation of a selenenylsulfide linkage in mammalian thioredoxin reductase was identified as having a key role in its activity. Identification of selenenylsulfide and/or diselenide linkages is therefore critical to the determination of the structure and function of selenoproteins. A selenopeptide, 298SGSAITUQCAENLPSLCSUQGLFAEEK324 (U = selenocysteine), was isolated from a tryptic digest of rat selenoprotein P. Its two cysteine residues and two selenocysteine (Sec) residues were determined to be present in oxidized form by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). The selenopeptide was subjected to partial reduction by dithiothreitol with immediate alkylation by iodoacetamide. This process was monitored by MALDI‐TOFMS to determine the number of alkylations that had taken place. The partially reduced and alkylated peptides were then analyzed by nano‐electrospray ionization tandem mass spectrometry and the results indicated that selenenylsulfide linkages Sec304–Cys314 and Cys306–Sec316 were present. It is concluded that selenoprotein P contains these two selenenylsulfide bonds. Copyright © 2005 John Wiley & Sons, Ltd.
Purification and initial characterization of a novel protein with factor Xa activity from Lonomia obliqua caterpillar spicules
Authors: Lilla S. , Pereira R. , Hyslop S. , Donato J. L. , Le Bonniec B. F. , de Nucci G.
Published: February 2005

A novel protein with factor Xa‐like activity was isolated from Lonomia obliqua caterpillar spicules by gel filtration chromatography and reversed‐phase high‐performance liquid chromatography. The protein had a mass of 20745.7 Da, as determined by mass spectrometry, and contained four Cys residues. Enzymatic hydrolysis followed by de novo sequencing by tandem mass spectrometry was used to determine the primary structure of the protein and the cysteine residues linked by disulfide bridges. The positions of 24 sequenced tryptic peptides, including the N‐terminal, were deduced by comparison with a homologous protein from the superfamily Bombycoidea. Approximately 90% of the primary structure of the active protein was determined. Copyright © 2005 John Wiley & Sons, Ltd.
Gas‐phase reactivity of the OP(OCH3)2+ phosphonium ion towards α,β‐unsaturated esters in a quadrupole ion trap
Authors: Leclerc Eric , Leon Emmanuelle , Taphanel Marie‐Hélène , Morizur Jean‐Pierre
Published: February 2005

Ion–molecule reactions between the OP(OCH3)2+ phosphonium ions and eight α,β‐unsaturated esters (methyl acrylate, ethyl acrylate, methyl crotonate, ethyl crotonate, methyl 3,3‐dimethylacrylate, ethyl 3,3‐dimethylacrylate, methyl methacrylate and ethyl methacrylate) were performed in a quadrupole ion trap mass spectrometer. The OP(OCH3)2+ phosphonium ions, formed by electron ionization from neutral trimethyl phosphite, were found to react with α,β‐unsaturated esters to give an adduct [RR′CCR″COOR″′, OP(OCH3)2]+, which lose spontaneously a molecule of trimethyl phosphate (R″′CH3) or dimethyl ethyl phosphate (R″′C2H5). An ion corresponding to a protonated trialkyl phosphate is also observed when substituent R″H. To confirm the experimental results, and to elucidate the mechanism for the formation of the ionic species, a theoretical study using the density functional theory (DFT) approach was carried out. The potential energy surface obtained from B3LYP/6–31G(d,p) calculations for the reaction between OP(OCH3)2+ and methyl acrylate is described. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization of chemically modified steroids for doping control purposes by electrospray ionization tandem mass spectrometry
Authors: Thevis Mario , Bommerich Ute , Opfermann Georg , Schänzer Wilhelm
Published: February 2005

The discovery of the designer steroid tetrahydrogestrinone (THG) in elite athletes' doping control samples in 2003 demonstrated the availability of steroid derivatives prepared solely for doping purposes. Modern mass spectrometers utilizing electrospray ionization and collisionally activated dissociation (CAD) of analytes allow the structural characterization of steroids and their derivatization sites by the elucidation of fragmentation behaviors. A total of 21 steroids comprising either a 4,9,11‐triene, a 3‐keto‐4‐ene or a 3‐keto‐1‐ene nucleus were investigated regarding their dissociation pathways, deuterated analogues were synthesized and fragmentation routes were postulated, permitting the identification of steroidal structures and modifications. Compounds based on a 4,9,11‐triene steroid with an ethyl residue at C‐13 (gestrinone analogues) generate abundant fragment ions at m/z 241 and 199, whereas the substitution of the C‐13 ethyl group by a methyl residue (trenbolone analogues) results in a shift of m/z 241 to 227. Substances related to testosterone with a 3‐keto‐4‐ene structure give rise to abundant fragment ions at m/z 109 and 97 whereas steroids with a 3‐keto‐1‐ene nucleus eliminate the A‐ring including the carbons C‐1–C‐4, in addition to C‐19 that is proposed to migrate from C‐10 to C‐1 under CAD conditions. Copyright © 2005 John Wiley & Sons, Ltd.