Arsenic accumulation by edible aquatic macrophytes.

Edible aquatic macrophytes grown in arsenic (As)-contaminated soil and sediment were investigated to determine the extent of As accumulation and potential risk to humans when consumed. Nasturtium officinale (watercress) and Diplazium esculentum (warabi) are two aquatic macrophytes grown and consumed in Hawaii. Neither has been assessed for potential to accumulate As when grown in As-contaminated soil. Some former sugarcane plantation soils in eastern Hawaii have been shown to have concentrations of total As over 500 mg kg(-1). It was hypothesized that both species will accumulate more As in contaminated soils than in non-contaminated soils. N. officinale and D. esculentum were collected in areas with and without As-contaminated soil and sediment. High soil As concentrations averaged 356 mg kg(-1), while low soil As concentrations were 0.75 mg kg(-1). Average N. officinale and D. esculentum total As concentrations were 0.572 mg kg(-1) and 0.075 mg kg(-1), respectively, corresponding to hazard indices of 0.12 and 0.03 for adults. Unlike previous studies where watercress was grown in As-contaminated water, N. officinale did not show properties of a hyperaccumulator, yet plant concentrations in high As areas were more than double those in low As areas. There was a slight correlation between high total As in sediment and soil and total As concentrations in watercress leaves and stems, resulting in a plant uptake factor of 0.010, an order of magnitude higher than previous studies. D. esculentum did not show signs of accumulating As in the edible fiddleheads. Hawaii is unique in having volcanic ash soils with extremely high sorption characteristics of As and P that limit release into groundwater. This study presents a case where soils and sediments were significantly enriched in total As concentration, but the water As concentration was below detection limits.

ERM proteins of the lens.

Ezrin and radixin and protein 4.1 were detected in the lens of the eye. These proteins were mainly present in the young elongating cortical fiber cells and localized to the plasma membranes. Moesin was not detected. Ezrin, radixin, and protein 4.1 provide another means whereby actin is linked to the plasma membrane in addition to the known adherens junctions in the lens.

Interpretation of electrospray/ion trap mass spectra of bile acids and other surfactants.

Electrospray spectra of various bile acids and other surfactants were obtained using an ion trap instrument. Bile acids and bile acid derivatives such as 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) self associate to form micelles in a stepwise process. Their spectra show a distinct pattern of aggregation, with ions evenly separated in the m/z space. A new parameter, n/z, can be used to characterize such ions, where n is the number of molecules and z is the charge of the aggregate. The values of z were determined using multi-stage mass spectrometry (MS(n)) and high resolution in the ion trap.

Analysis of human skin emanations by gas chromatography/mass spectrometry. 2. Identification of volatile compounds that are candidate attractants for the yellow fever mosquito (Aedes aegypti).

Volatile compounds emanated from human skin were studied by gas chromatography/mass spectrometry (GC/MS). The purpose of this study was to identify compounds that may be human-produced kairomones which are used for host location by the mosquito, Aedes aegypti (L.). The procedure used to collect volatiles was chosen because of prior knowledge that attractive substances can be transferred from skin to glass by handling. Laboratory bioassays have shown that the residuum on the glass remains attractive to mosquitoes until the compounds of importance evaporate. The sampling and analytical procedures modeled the above-cited process as closely as possible except that the evaporation of compounds from the glass surface was accomplished by thermal desorption from glass beads in a heated GC injection port. This made possible the solventless injection of volatiles onto the column. The compounds were cryofocused on the head of the column with liquid nitrogen prior to GC separation. A single stage of mass spectrometry on a triple quadrupole instrument was used for mass analysis. A combination of electron ionization and pulsed positive ion/negative ion chemical ionization modes on two different GC columns (one polar, one relatively nonpolar) was used to identify most of the 346 compound peaks detected by this technique.

Analysis of human skin emanations by gas chromatography/mass spectrometry. 1. Thermal desorption of attractants for the yellow fever mosquito (Aedes aegypti) from handled glass beads.

Handled glass has the ability to collect and concentrate nonaqueous human skin emanations while minimizing the collection of aqueous perspiration. Compounds originating from the skin and collected on glass have previously been found to attract the Aedes aegypti species of mosquito. Therefore, glass beads were used as the medium to collect skin emanations from humans for subsequent chemical analysis. This process consisted of a 5-15-min collection of sample on glass beads, followed by loading the beads into a gas chromatograph (GC) injector insert for subsequent desorption of the collected compounds onto the GC column. After cryofocusing by liquid nitrogen at the head of the column, the thermally desorbed compounds were analyzed by GC/MS. Microscale purge and trap introduction was also used to provide complementary information. In this case, the beads are held in a round-bottom flask, purged with nitrogen, and heated as the concentrator collects the headspace above the beads. The chromatograms produced by both of these sample introduction methods demonstrate good resolution of a complex sample. Cryofocusing volatiles from handled glass allowed identification of lactic acid, aliphatic fatty acids, and other polar to nonpolar compounds of moderate volatility while purge and trap allowed detection of nonpolar to moderately polar compounds of high volatility.

Flavanone absorption after naringin, hesperidin, and citrus administration.

Disposition of citrus flavonoids was evaluated after single oral doses of pure compounds (500 mg naringin and 500 mg hesperidin) and after multiple doses of combined grapefruit juice and orange juice and of once-daily grapefruit. Cumulative urinary recovery indicated low bioavailability ( < 25%) of naringin and hesperidin. The aglycones naringenin and hesperitin were detected in urine and plasma by positive chemical ionization-collisionally activated dissociation tandem mass spectrometry (PCI-CAD MS/MS). After juice administration, PCI-CAD MS/MS detected naringenin, hesperitin, and four related flavanones, tentatively identified as monomethoxy and dimethoxy derivatives. These methoxyflavanones appear to be absorbed from juice. Absorbed citrus flavanones may undergo glucuronidation before urinary excretion.

Internal pulsed valve sample introduction on a quadrupole ion trap mass spectrometer.

A pulsed valve positioned just outside the ion trap electrodes (within the vacuum chamber) has been characterized. The observed gas pulse widths and the maximum ion intensities were found to decrease as the distance between the pulsed valve and the ion trap electrodes increased. An explanation is presented within. The pulsed valve was found to impart temporal separation in ion-molecule reactions by permitting the removal of interfering neutrals. Other factors that affect the degree of temporal separation also are presented.

Phase II study of neoadjuvant chemotherapy and radiation therapy with thoracotomy in the treatment of clinically staged IIIA non-small cell lung cancer.

BACKGROUND: The purpose of this study was to assess the ability of administering to patients induction chemotherapy with carboplatin and etoposide (VP-16), followed by full-course radiation therapy and weekly carboplatin with tolerable toxicity as preoperative therapy to down-stage disease thus allowing the resection of clinically staged IIIA non-small cell lung cancer. METHODS: Twenty-eight eligible patients with good performance status and previously untreated, marginally resectable stage IIIA non-small cell lung cancer received induction chemotherapy with carboplatin (dosed per the Egorin formulation), and VP-16 (100 mg/m2) followed by 6000 cGy of chest radiotherapy over six weeks administered concurrently with weekly doses of 100 mg/m2 of carboplatin. Patients who had either responsive or stable disease underwent thoracotomy, with attempted surgical resection of the primary lung lesion and the areas of abnormal adenopathy. Procedures involving less than a pneumonectomy were used whenever feasible. RESULTS: Fifty-two cycles of induction chemotherapy were administered. The average initial dose of carboplatin was 407 mg/m2. Toxicity was tolerable with grade 3-4 neutropenia and/or thrombocytopenia in 48 and 27% of the patients. There were no septic deaths. Full-dose radiotherapy was administered to 82% of patients, with 73% receiving at least five weekly doses of carboplatin. The radiographically assessed response rate to the neoadjuvant treatment was 64% (partial response, 46%; minimal response, 18%). Sixteen patients underwent gross tumor resection with 12 (43%) having negative pathologic margins. Six patients had pneumonectomy. There were three perioperative deaths (19%); two were secondary to respiratory failure after the patients underwent a pneumonectomy. The median survival for all 28 patients was 15 months, and for the 16 patients undergoing thoracotomy was 23 months. Eight patients were alive and in remission, with follow-up ranging from 8 to 31 months. CONCLUSIONS: The authors conclude that (1) carboplatin and VP-16, followed by full-dose radiotherapy with weekly carboplatin administration, is a well tolerated and effective regimen in the treatment of patients with marginally resectable stage IIIA non-small cell lung cancer; and (2) full-course radiotherapy can be administered before surgical resection without additional surgical morbidity or mortality.

Gas-phase ion-molecule reactions: a model for the determination of biologically reactive electrophilic contaminants in the environment.

A promising instrumental technique has been investigated to rapidly screen complex environmental samples for chemical contaminants having the propensity to covalently bond to biomacromolecules such as DNA. Radical molecular ions of pyridine, a model compound for nucleophilic bases of DNA, were mass-selected and allowed to react with electrophilic environmental contaminants in the collision cell of a triple quadrupole mass spectrometer. Analytes were introduced into the collision cell via a gas chromatographic column. Reactive chemicals are then characterized by scanning Q3 to identify associative reaction products. A good qualitative correlation was observed for the gas-phase reactivity of a series of electrophilic reagents with both their alkylating reactivity in solution (4-(4-nitrobenzyl)pyridine) and AMES test mutagenicity which had been previously published. Femtomole limits of detection for specific associative reaction products were demonstrated. Gas-phase reactions of ions of environmental contaminants (introduced into the source) with neutral pyridine (in the collision cell) were also investigated. Reactions of the radical molecular ion of the allyl reagents with neutral pyridine were similar to results from the mass-selected reaction of the pyridine radical molecular ion with neutral allylic reagents.

Short-column gas chromatography/tandem mass spectrometry for the detection of underivatized anabolic steroids in urine.

Short-column (3.5 m) gas chromatography (GC)/tandem mass spectrometry (MS/MS) has been investigated for the detection of structurally related, underivatized anabolic steroids in urine. The approach described here demonstrates the ability to rapidly and qualitatively detect underivatized anabolic steroids in spiked urine matrices. In this approach, underivatized steroids are determined using a short-column GC separation, ionized by positive ion chemical ionization, and detected by selected reaction monitoring MS/MS. This approach permits positive identification of underivatized anabolic steroids based on retention time and the production of characteristic product ions. Preliminary detection limits studies in spiked urine samples showed quantitative results between 2 and 40 ng steroid per milliliter of uterine. The potential advantages of this approach compared to present screening methods based on conventional (30 m) GC/MS are its rapidity and selectivity. Reliable qualitative identification can be performed with a short-column GC/MS/MS analysis of less than 6 min with a reduction in sample preparation time due to the elimination of the derivatization step.

Negative chemical ionization in quadrupole ion trap mass spectrometry: Effects of applied voltages and reaction times.

The effects of applied voltages and reaction times on negative ion chemical ionization in the quadrupole ion trap are investigated. Mass-selected ejection of undesired reagent ions and selective mass storage of only negative ions are required for practical negative ion chemical ionization. This is achieved by application of rf and dc voltages to the ring electrode to control the mass-to-charge ratios one polarity) of ions stored, as well as by application of a supplemental rf voltage applied across the endcap electrodes to selectively eject ions of a particular mass-to-charge ratio. Even with careful control of these parameters, negative chemical ionization is not as sensitive as electron ionization and positive chemical ionization because of the lack of thermal electrons in the ion trap. Mass selection of the hydroxide anion as a reagent ion and exclusion of all positive ions provide [M - H](-) ions with little or no fragmentation for a wide variety of compounds.

Infrared multiple photon dissociation in the quadrupole ion trap via a multipass optical arrangement.

The design of a novel multipass optical arrangement for use with infrared multiple photon dissociation (IRMPD) in the quadrupole ion trap is presented. This design circumvents previous problems of limited IR laser power, small IR absorption cross sections for many molecules, and the limited ion statistics of trapping and detection of ions for IRMPD in the quadrupole ion trap. In contrast to previous designs that utilized the quadrupole ion store, the quadrupole ion trap was operated in the mass selective instability mode with concurrent resonance ejection. The instrumental design consisted of a modified ring electrode with three spherical concave mirrors mounted on the inner surface of the ring. This modified design allowed for eight laser passes across the radial plane of the ring electrode. IRMPD of protonated bis(2-methoxyethyl)ether (diglyme) was used to characterize the performance of the multipass ring electrode. Two consecutive reactions for the IRMPD of protonated diglyme were observed with a lower energy channel predominant at less than 0.6 J (irradiation times from 1 to 30 ms) and a second channel predominant at energies greater than 0.6 J (irradiation times > 30 ms). Other studies presented include a discussion of the dissociation kinetics of protonated diglyme, the use of a pulsed valve for increased trapping efficiency of parent ion populations, and the effects of laser wavelength and of ion residence time in the radial plane of the ring electrode on photodissociation efficiency.

The effects of psychological factors in sports medicine rehabilitation adherence.

This study investigated the influence of achievement motivation and self-esteem on injury treatment adherence in a general sample of injured patients receiving treatment in a sports medicine clinic. Subjects consisted of both injured athletes and workers who had incurred an on-the-job injury. Based on scales of self-esteem and achievement motivation, patients were categorized as either high or low in self-esteem certainty, self-esteem level, tendency to be task-involved, and tendency to ego-involved in tasks. Treatment adherence was measured by number of missed appointments and by physical therapist ratings of effort and progress. It was found that patients low in self-esteem certainty and high in ego-involvement tended to miss the most treatment appointments. Contrary to previous findings, task-involvement was not found to be related to treatment adherence.

Carboplatin, etoposide, and radiotherapy, followed by surgery, for the treatment of marginally resectable non-small cell lung cancer.

The present study was undertaken in order to determine the feasibility and efficacy of induction chemotherapy with carboplatin and etoposide, followed by weekly carboplatin and full-course radiotherapy as pre-operative therapy for marginally resectable non-small cell lung cancer (NSCLC). Twenty-eight patients with good Eastern Cooperative Oncology Group (ECOG) performance status ratings and stage IIIA NSCLC received induction chemotherapy with carboplatin (dose computed with the Egorin formula, days 1 and 29) and etoposide (100 mg/m2/day, days 1 through 3 and 29 through 31). This was followed by 100 mg/m2 weekly carboplatin given over 6 weeks, concurrently with 60 Gy radiotherapy. Patients with either responsive or stable disease underwent thoracotomy 4 weeks after the completion of combined-modality therapy. All 28 patients received the first chemotherapy cycle (average carboplatin dose, 407 mg/m2; range, 195 to 586 mg/m2). World Health Organization (WHO) grade 3/4 neutropenia and thrombocytopenia were observed in 53 and 34% of patients, respectively. There were three febrile neutropenic episodes, but no septic deaths. Five patients (18%) required dose reductions prior to the second chemotherapy cycle, but the dose intensity of carboplatin was maintained (average dose, 390 mg/m2; range, 195 to 586 mg/m2). In all, 82% of patients received full-dose radiotherapy, and 73% received at least five of six planned concurrent weekly carboplatin doses. Carboplatin doses were most frequently delayed for thrombocytopenia and/or leukopenia. Carboplatin did not increase the incidence of radiation-induced esophagitis. Only three patients required interruption of radiotherapy, for esophagitis (two patients) and persistent thrombocytopenia (one patient). The response rate to pre-operative therapy was 64%. In this study, we demonstrated the ability to deliver escalated doses of carboplatin with standard-dose etoposide as induction chemotherapy with reasonable myelotoxicity. The combined-modality therapy was well tolerated, and the addition of weekly carboplatin did not result in increased radiation-related toxicity. This neoadjuvant regimen is active in the treatment of locally advanced NSCLC, and compares favorably to other cisplatin-based regimens.

Nonlinear resonance effects during ion storage in a quadrupole ion trap.

Contributions of higher-order fields to the quadrupolar storage field produce nonlinear resonances in the quadrupole ion trap. Storing ions with secular frequencies corresponding to these nonlinear resonances allows absorption of power from the higher-order fields. This results in increased axial and radial amplitudes which can cause ion ejection and collision-induced dissociation (CID). Experiments employing long storage times and/or high ion populations, such as chemical ionization, ion-molecule reaction studies, and resonance excitation CID, can be particularly susceptible to nonlinear resonance effects. The effects of higher-order fields on stored ions are presented and the influence of instrumental parameters such as radiofrequency and direct current voltage (qZ and az values), ion population, and storage time are discussed.

Optimization of short-column gas chromatography/electron ionization mass spectrometry conditions for the determination of underivatized anabolic steroids.

A gas chromatographic/mass spectrometric method based on the use of short capillary gas chromatograph columns (3-5 m) and electron ionization mass spectrometry has been optimized and evaluated for the determination of underivatized anabolic steroids. The short-column gas chromatographic/mass spectrometric method was shown to result in short analysis times and to require minimal sample preparation, but suffered from some loss in sensitivity and chromatographic resolution compared with conventional gas chromatographic/mass spectrometric techniques for derivatized steroids. Therefore, short-column gas chromatographic conditions were optimized to maximize the sample transfer efficiency (sensitivity) from the gas chromatograph into the ion source of the mass spectrometer, while maintaining chromatographic integrity and minimizing thermal decomposition. Mass spectrometric conditions were optimized to maximize ionization efficiency with respect to the intensity of the molecular ion and degree of fragmentation such that positive identification of each steroid could be made based on the resulting mass spectra. Under optimized conditions, we have shown that underivatized anabolic steroids spiked into urine samples can be determined at low-nanogram levels using short-column chromatography/full-scan electron ionization mass spectrometry.

Probing trapped ion energies via ion-molecule reaction kinetics: Quadrupole ion trap mass spectrometry.

We present a detailed study of the energies of the ions stored in a quadrupole ion trap mass spectrometer (QITMS). Previous studies have shown that the rate constant, k, for the charge exchange reaction Ar(+) N(+) 2 →, N(+) 2+Ar increases with increasing ion-molecule center-of-mass kinetic energy (K.E.cm). Thus, we have determined k for this chemical "thermometer" reaction at a variety of Ar and N2 pressures and have assigned K.E.cm values as a function of the q2 of the Ar(+) ion both with and without He buffer gas present in the trap. The K.E.cm energies are found to lie within the range 0.11-0.34 eV over the variety of experimental conditions investigated. Quantitative "cooling" effects due to the presence of He buffer gas are reported, as are increases in K.E.cm due to an increase in the q2 of the Ar(+) ion. "Effective" temperatures of the Ar(+) ions in He buffer are determined based on a Maxwell-Boltzmann distribution of ion energies. The resulting temperatures are found to lie within the range ≈ 1700-3300 K. We have also examined the K.E.cm, values arising from the chemical thermometer reaction of O(+) 2 with CH4, as previous assignments of effective ion temperatures based on this reaction have been called into question.

Alternating RF/DC Isolations for Quantitation with Coeluting Internal Standards in Gas Chromatography/Ion Trap Mass Spectrometry.

A new ion trap scan function for gas chromatography/mass spectrometry (GC/MS) quantitation is described that employs alternating mass-selective storage (rf/dc isolation) of ions from an analyte and its coeluting isotopically labeled internal standard. This scan includes two separate ionization/isolation/mass analysis sequences within the same scan function, each optimized for either the analyte or the internal standard. This results in alternating between analyzing the analyte and the internal standard during their coelution. The method is conceptually similar to using two different scan functions to analyze either the analyte or the internal standard in alternating scans; however, it is much faster because it eliminates the slow procedure of continuously downloading alternating scan functions from disk. This allows more data points to be obtained over a GC peak, resulting in more reproducible GC peak profiles as well as better sensitivity and precision. Results of calibration curves spanning four orders of magnitude (0.5 pg to 5 pg injected on column) obtained by using this method give excellent linear correlations (r (2) > 0.9990) and precision (relative standard deviations of triplicate injections < 10%).

Yeast mitochondria (Saccharomyces cerevisiae) contain Ca(2+)-independent phospholipase A1 and A2 activities: effect of respiratory state.

We demonstrate that both phospholipase A1 and phospholipase A2 are associated with isolated yeast mitochondria (Saccharomyces cerevisiae). Activity assays indicate that, unlike most other mitochondrial phospholipases A, the yeast enzymes are Ca(2+)-independent with acidic (pH 4-5) as well as alkaline (pH 8-9) pH optima. Data obtained with mitochondria isolated from either fermenting or respiring cells, and initial observations with a petite strain, strongly suggest that a phospholipase A2 with an acidic pH optimum functions in the in vivo adaptation and maintenance of mitochondrial membranes required for respiration.