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Edward White

Publications and source records attributed to Edward White.

10 recordsLinked to original sources
PubMed2005

Quantitative determination of capsaicinoids by liquid chromatography-electrospray mass spectrometry.

Eight naturally occurring capsaicinoids have been determined in Capsicum by use of high-purity standards, with norcapsaicin as an internal standard. The solid standards were rigorously checked for purity. The sensitivity of electrospray ionization (ESI), atmospheric-pressure chemical ionization (APCI), and coordination ion-spray (CIS; with silver) toward the capsaicinoids were measured and compared. The highest sensitivity was found for positive-ion ESI. Method validation of the liquid chromatography-ESI-mass spectrometry (LC-ESI-MS) determination is reported, including tests for repeatability (4%), detection limit (5 pg injected), linear range (20-6 ng injected), quantitation (excellent linearity; < 2% relative standard deviation), and recovery (99-103%). The major and minor capsaicinoids in a commercial plant extract and in chili pepper fruits were quantified.

Capsaicin↗
PubMed2005

Incidence of male breast cancer in california, 1988-2000: racial/ethnic variation in 1759 men.

Breast cancer among males is rare, accounting for less than 1% of all breast cancers in the United States. Although it is rare, it can cause significant morbidity and mortality. We analyzed data from 1759 California males whose diagnosis of breast cancer was made between 1988 and 2000 and reported to the population-based California Cancer Registry. Cases were primary, microscopically confirmed in situ and invasive breast cancer. Age-adjusted incidence rates per 100,000 men were highest in Blacks (1.65), intermediate in whites (1.31) and lowest in Hispanics and Asian/Pacific Islanders (0.68, 0.66, respectively). Age at diagnosis differed by race (p = 0.001) with blacks diagnosed at an earlier age than whites or Asians/Pacific Islanders. Stage at diagnosis also differed by race (p = 0.001) with blacks more likely to be diagnosed at distant stage. Further investigation showed that blacks and Hispanics were more likely to be diagnosed with tumors 5 cm in diameter or greater. The proportion of men having surgery following a diagnosis of breast cancer also varied by race/ethnicity (p = 0.001) with blacks least likely to have surgery following diagnosis. Understanding racial/ethnic variation in male breast cancer may provide clinical and etiologic implications for breast cancer in different populations.

Adult↗
PubMed2005

Bacterial analysis by MALDI-TOF mass spectrometry: an inter-laboratory comparison.

Bacterial analysis by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry has been demonstrated in numerous laboratories, and a few attempts have been made to compare results from different laboratories on the same organism. It has been difficult to understand the causes behind the observed differences between laboratories when different instruments, matrices, solvents, etc. are used. In order to establish this technique as a useful tool for bacterial identification, additional efforts in standardizing the methods by which MALDI mass spectra are obtained and comparisons of spectra from different instruments with different operators are needed. Presented here is an extension of our previous single-laboratory reproducibility study with three different laboratories in a controlled experiment with aliquots of the same bacterial culture, matrix stock solution, and calibrant standards. Using automated spectral collection of whole-cell bacteria and automated data processing and analysis algorithms, fingerprints from three different laboratories were constructed and compared. Nine of the ions appeared reproducibly within all three laboratories, with additional unique ions observed within each of the laboratories. An initial evaluation of the ability to use a fingerprint generated within one laboratory for bacterial identification of a sample from another laboratory is presented, and strategies for improving identification rates between laboratories is discussed.

Bacterial Proteins↗
PubMed2004

Development and evaluation of a reference measurement procedure for the determination of total 3,3',5-triiodothyronine in human serum using isotope-dilution liquid chromatography-tandem mass spectrometry.

3,3',5-Triiodothyronine (T3) is an important diagnostic marker for thyroid function. A reference measurement procedure (RMP) for total T3 in serum involving isotope dilution coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. The method uses solid-phase extraction with mixed-mode retention mechanisms of reversed phase and ion exchange prior to reversed-phase LC/MS/MS. In addition to a labeled T3 internal standard (T3-13C9), labeled thyroxine (T4-d5) is also added to serum samples in order to monitor the degradation of T4 to T3. The accuracy of the measurement was evaluated by a recovery study for added T3 and was supported by a comparison study with the other RMP. The recovery of the added T3 ranged from 98.9% to 99.4%. The results of this method and the other RMP agreed to within 1%. Samples of frozen serum pools were prepared and measured in three separate sets. Excellent reproducibility was obtained with within-set coefficients of variation (CVs) ranging from 0.8% to 1.6% and between-set CVs ranging from 1.9% to 2.6%. Excellent linearity was also obtained with correlation coefficients of all linear regression lines (measured intensity ratios vs mass ratios) ranging from 0.9995 to 0.9996. The detection limit at a signal-to-noise ratio of approximately 3 was 1 pg of T3. The T4 degradation during sample preparation was minimized to a small percentage (no more than 3% of the T3 values) by use of antioxidants (ascorbic acid, dithiothreitol, citric acid) and can be accounted for in the T3 measurement process. This well-characterized LC/MS/MS method for total serum T3, which demonstrates good accuracy and precision, low susceptibility to interferences, accountability of the conversion of T4 to T3, and comparability with the other RMP, qualifies as a reference measurement procedure and can be used to provide an accuracy base to which routine methods for T3 can be compared.

Chromatography, Liquid↗
PubMed2004

Validity of rim area measurements by different reference planes.

PURPOSE: Reference plane description of the neuroretinal rim in scanning laser tomography should correctly represent optic nerve morphology. We evaluated how well rim area analysis by different reference planes agreed with the appearance of rim area in disc images. METHODS: Three expert observers subjectively and repeatedly analyzed rim area in Heidelberg Retina Tomograph (HRT) images so that each optic disc was measured six times in 100 eyes, 50 normal and 50 glaucoma. Rim area was evaluated globally and in 30 degree sectors. Agreement between rim appearance, as subjectively analyzed, and objective analysis by an experimental reference plane, the standard reference plane, and a reference plane fixed 320 microm below the reference ring was assessed in HRT images. RESULTS: Subjective analysis of rim area in HRT images was consistent between expert observers. Their analysis of rim appearance agreed more closely with experimental reference plane analysis than analysis by the standard or 320-microm reference planes; this was true globally and in every region of the nerve (P = 0.000). The experimental reference plane yielded higher estimates of rim area than did the standard or 320-microm reference planes. CONCLUSION: There was closer correspondence between the appearance of the neuroretinal rim in images and description by the experimental reference plane compared with description by the standard and 320-microm reference planes.

Aged↗
PubMed2004

Making my mark.

As a schoolboy, Professor Edward White was encouraged to achieve and take responsibility: qualities he has found have helped him in his lifelong vocation in health care and research. Here, he acknowledges the important role that others have played in his career, and how, although he does not believe in fate, he has often been fortunate enough to be in the right place at the right time.

Career Choice↗
PubMed2003

The struggle for methodological orthodoxy in nursing research: the case of mental health.

This paper is not intended as an exhaustive review of contemporary mental health nursing research. Rather, the intention is to explore some of the competing arguments for different methodological approaches in social research, using mental health nursing as a case example. The paper questions the extent to which the artificially dichotomized debate over quantitative versus qualitative research impacts upon the working lives of practitioners, managers and policy makers. In particular, the paper traces the development of survey method, during this its centennial anniversary year. It also traces its subsequent decline, in favour of what will be referred to as the new methodological orthodoxy in nursing research. It is also interwoven with occasional accounts of personal experience, drawn from an international perspective. The paper calls for a reapproachement between different wings of methodological opinion, in deference to a publicly unified position for nursing research in which the achievement of quality becomes the over-arching concern.

Humans↗
PubMed2002

The expression of the developmentally regulated proto-oncogene Pax-3 is modulated by N-Myc.

N-Myc is a member of the Myc family of transcription factors that have been shown to play a pivotal role in cell proliferation and differentiation. In this report, we have investigated the relationship between N-Myc and the developmental control gene Pax-3. Using transient transfection assays, we show that the Pax-3 promoter is activated by both N-Myc-Max and c-Myc-Max. Moreover, we show that Myc regulation of Pax-3 promoter activity is dependent upon a noncanonical E box site in the 5' promoter region of Pax-3. In addition, we show that ectopic expression of both N-Myc and c-Myc leads to increased expression of Pax-3 mRNA. Furthermore, we show that Pax-3 mRNA expression is cell cycle-regulated and that the 5' promoter region of Pax-3 (bp -1578 to +56) can direct cell cycle-dependent gene expression with kinetics similar to that of the endogenous transcript. Site-directed mutagenesis of the E box site within the Pax-3 promoter significantly altered the pattern of expression through the cell cycle. These results suggest that the Myc family of transcription factors may modulate Pax-3 expression in vivo.

Animals↗