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Biomedical subjects

L Taylor

Publications and source records attributed to L Taylor.

At least 73 records · Page 4Linked to original sources
PubMed1999

1997 Peritoneal Dialysis-Core Indicators Study: Dialysis Adequacy and Nutritional Indicators Report.

The 1997 Peritoneal Dialysis-Core Indicators Study: Dialysis Adequacy and Nutritional Indicators Report documents the current status of peritoneal dialysis within the United States. A national random sample of adult peritoneal dialysis (PD) patients participating in the United States End Stage Renal Disease (ESRD) program was surveyed. PD subjects were large, with a mean body weight of 76 +/- 18.9 kg (mean +/- 1 SD) and a body mass index (BMI) of 27 +/- 6.4. The dialysis prescriptions documented achieved a mean weekly Kt/Vurea (wKt/V) and weekly creatinine clearance (wCrCl) of 2. 45 +/- 2.29 and 65.5 +/- 35.2 L/wk/1.73m2, respectively. The serum albumin of these patients was 3.5 +/- 0.48 g/dL, their normalized protein equivalent of nitrogen appearance (nPNA) 1.0 +/- 0.63 g/kg/d, and their normalized creatinine appearance rate (nCAR) 14 +/- 6.0 mg/kg/d. Serum albumin correlated meagerly but in a positive fashion with BMI, nPNA, and nCAR, and negatively with wCrCl. Among adult US PD patients, serum albumin values appear to correlate poorly with alternative measures of nutritional status and are inversely related to the intensity of renal replacement therapy. The presumptive dietary protein intake (nPNA) and creatinine appearance rate (nCAR) derived for PD patients do correlate in a positive fashion with dialysis delivery, at least up to a wCrCl of 60 to 80 L/wk/1.73 m2 and wKt/V = 2.1, but their values suggest that 30% to 50% of PD patients have marginal nutritional status.

Adolescent↗
PubMed1999

Mental health in schools and system restructuring.

Because health is not the primary business of schools, a school's response to mental health and psychosocial concerns usually is limited to targeted problems seen as direct barriers to learning. And because resources are sparse, priority is given to problems defined in legislative mandates. As a result, school-based mental health services are available only to a small proportion of the many students who require assistance, and interventions generally are narrowly focused and short-term. To better meet the needs of those served and to serve greater numbers, emerging trends are pushing for restructuring of school-owned services and greater linkage with community resources to develop multifaceted, comprehensive, integrated approaches. This review (a) provides an overview of what schools currently do related to mental health and psychosocial concerns, (b) clarifies key emerging trends, and (c) explores implications for major systemic changes.

Adolescent↗
PubMed1999

Effect of immunization against melatonin on prolactin concentrations and the timing of reproductive transitions in ewes.

The objective of this experiment was to develop a procedure for immunizing ewes against melatonin that would alter the effects of changing photoperiod on seasonal reproduction and prolactin secretion. Ewes were immunized against human serum albumin (HSA) as controls (n = 9) or a melatonin-human serum albumin conjugate (0.25 mg; n = 10) on December 14th (Day 0) and boosted 9 times. They were maintained on natural photoperiod and then transferred indoors and exposed to long days for 35 d, followed by short days for 146 d, long days for 93 d, and short days for a further 123 d. Antibody titers to melatonin (at a serum dilution of 1:1,250) were significantly higher in immunized ewes (27.3 +/- 6.6%) than controls (0.7 +/- 0.1%; P < 0.001). At the end of the experiment, antibody titers in immunized ewes (at dilution of 1:50) were higher in blood (43.7 +/- 8.2%) than in cerebrospinal fluid (10.8 +/- 3.9%; P < 0.05), and highly correlated (r2 = 0.746). Onset of the breeding season was advanced slightly after the second transfer from long to short days in immunized ewes (April 12 +/- 3 d) compared with controls (April 25 +/- 3 d; P < 0.05). Mean serum prolactin concentrations were lower (P < 0.05) in melatonin-immunized ewes compared with controls on natural photoperiod, after transfer from long to short days, during long days, and after the second transfer from long to short days. In conclusion, despite melatonin-immunization increasing antibody titers in blood and cerebrospinal fluid, and decreasing prolactin concentrations over much of the experiment, minimal effects on the timing of reproductive transitions in the ewes were evident. This discrepancy between the response of the prolactin and reproductive axes to melatonin immunization supports the hypothesis of a dual site of action of melatonin, with melatonin acting in the pituitary gland to mediate the effects of photoperiod on prolactin secretion and in the mediobasal hypothalamus to affect reproductive responses.

Animals↗
PubMed1999

Cognitive reactivity and depressotypic information processing in children of depressed mothers.

Although high-risk research suggests that children of depressed mothers are at increased risk for psychological disorders, the mechanisms of this risk are not well understood. In the current study, the information processing of children of depressed mothers was compared with that of children whose mothers were not depressed. Half of each group received a priming induction designed to activate cognitive schemas prior to assessment. All children then completed a self-referent processing task that examined the recall of negative and positive information. Results indicate that when primed, at-risk children showed a less positive self-concept and more negative information processing than did the children in the other groups. These data may offer potential clues into the mechanisms of cognitive vulnerability in at-risk children.

Adult↗
PubMed1999

Searching the right database. A comparison of four databases for psychiatry journals.

Journal coverage is one factor that affects the retrieval of relevant information from bibliographic databases. The aims of this study were to investigate the coverage of databases for psychiatry journals, and to assess the overlap between databases. Psychiatry journals were identified using Ulrich's International Periodicals Directory and then analysed to see which bibliographic databases indexed the most journals. A total of 213 abstracting and indexing services were listed as indexing at least one of the 977 psychiatry journals identified. The four most frequently cited databases (PSYCLIT, EMBASE, BIOSIS and MEDLINE) indexed 506 (52%) of the psychiatry journals. Of these 506 journals, PSYCLIT indexed 367 (73%), EMBASE 337 (67%), BIOSIS 243 (48%) and MEDLINE 236 (47%). Combining the databases with the highest yields (PSYCLIT and EMBASE) increased the number of journals indexed to 461 (91%). The four databases combined accounted for 90% of all psychiatry journals found to be indexed by at least one abstracting and indexing service. More than 400 journals were not indexed at all. Variations in the overlap between PSYCLIT, EMBASE, BIOSIS and MEDLINE, and the high proportion (35%) of journals indexed in only one of these four databases emphasize the importance of searching more than one or even two databases to ensure optimal coverage of the literature.

Abstracting and Indexing↗
PubMed1999

Psychometric validation of a constipation symptom assessment questionnaire.

BACKGROUND: Clinical management of constipation is complicated by the lack of a gold standard for evaluation of symptoms. A constipation symptom assessment instrument, the PAC-SYM, was developed to address the patient perspective on the disorder. Instrument content was based on literature review and results of focus groups. METHODS: Two hundred and sixteen patients at nine sites participated in a 6-week psychometric evaluation of the PAC-SYM. The final instrument contained 12 items assigned to 3 subscales: stool symptoms, rectal symptoms, and abdominal symptoms. The psychometric properties of this final instrument were assessed. RESULTS: Internal consistency and test-retest reliability of the final instrument was high (Cronbach's alpha = 0.89; intraclass correlation = 0.75). Concurrent validity was supported by the correlation with both subject and investigator constipation severity ratings (r= 0.68 and 0.72, respectively; P < 0.0001). Scores were moderately correlated with instruments measuring quality of life. Comparison of treatment responders with nonresponders showed the ability of the instrument to differentiate between groups on the basis of clinical severity (t = -6.12, P < 0.0001 ). Scores changed significantly over time among responders, indicating instrument responsiveness. CONCLUSIONS: The PAC-SYM is internally consistent, reproducible under stable conditions, valid, and responsive to change and provides a comprehensive means to assess the effectiveness of treatment for constipation.

Adolescent↗
PubMed1999

Trends in births at and beyond term: evidence of a change?

OBJECTIVE: To examine trends in the distribution of births at and beyond term in New South Wales and in particular, to determine whether any changes are associated with changes in the obstetric practices of induction and elective caesarean section. DESIGN: Cross-sectional analytic study. SETTING: New South Wales, Australia. POPULATION: All 540,162 women delivering a singleton cephalic-presenting infant of gestational age > or = 37 weeks from 1 January 1990 to 31 December 1996. METHODS: Data were obtained from the New South Wales midwives data collection, a population-based surveillance system covering all births in New South Wales. The data were analysed to examine changes over time and associations between gestational age, maternal factors and onset of labour. MAIN OUTCOME MEASURES: Induction of labour and elective caesarean section rates. RESULTS: From 1990 to 1996 there was a significant decrease in births reported as 40 weeks of gestation, from 35,670 (46.3%) to 30,651 (40.3%). These declines were offset by significant increases in births at 38 and 39 weeks. Births > or = 42 weeks declined from 3321 (4.6%) to 2132 (2.8%). The decline in prolonged pregnancies was associated with increasing induction rates at 41 weeks. The re-distribution of some births from 40 to 38-39 weeks was associated with increasing rates of elective caesarean sections and induction at 38 and 39 weeks, and increasing maternal age. CONCLUSIONS: Clinicians appear to be implementing the recommendations of randomised controlled trials to offer induction after 41 weeks of gestation. However the trend of performing elective caesarean sections at earlier gestational ages may be unnecessarily putting some infants at increased risk of respiratory morbidity.

Adult↗
PubMed1999

The treatment and prevention of coronary heart disease in Canada: do older patients receive efficacious therapies? The Clinical Quality Improvement Network (CQIN) Investigators.

OBJECTIVES: To review the evidence for clinical efficacy and cost-effectiveness of proven medications in the treatment and prevention of myocardial infarction (MI) in older patients; to summarize Canadian data on treatment patterns and clinical outcomes for younger and older patients with coronary heart disease; to explore the reasons for gaps between best care, based on the evidence of efficacy from trials, and usual care, based on the population effectiveness audits; and to explore potential approaches to closing the care gaps. DESIGN: Review of the recent clinical trial literature on the management of MI, highlighting results in older patients. Review of medication utilization and outcomes data from a series of large, consecutively enrolled patient cohorts with acute MI (N = 7070) in a variety of cardiac care settings (10 centers in five Canadian provinces, including university-based teaching hospitals, community hospitals, cardiologist and family physician out-patient clinics) from 1987 to 1996. RESULTS: There is no qualitative interaction of cardiac therapies: thrombolytics, beta-blockers, acetylsalicylic acid (ASA), and statins are efficacious in all clinically relevant patient subgroups, including older people. However, there are consistent gaps between usual care and best care, particularly among older patients (in whom there is also a concomitantly higher mortality risk). Repeated multivariate analyses confirm older age to be an independent contributor to increased risk. Use of efficacious medications is, in contrast, consistently associated with increased survival. Analysis of temporal trends suggests beneficial changes in practice patterns and outcomes are possible to achieve. However, "best care" has not been rapidly or completely achieved. Review of strategies to close these care gaps suggests that audit and feedback, critical pathways, and multifactorial interventions involving patients and other members of the healthcare team as well as physicians may be the most efficacious strategies for change. CONCLUSIONS: Despite equal or enhanced efficacy, there is consistently less prescription of proven drugs among older cardiac patients. These care patterns may contribute to their enhanced risk. The causes underlying these practice patterns are complex, and their population impact may be undervalued by clinicians and managers. Improvement of these patterns is difficult, but ultimately it would be beneficial for this presently disadvantaged, readily identified, high risk patient population.

Aged↗
PubMed1999

HHV-8 (KSHV) is not associated with bacillary angiomatosis.

AIMS: Bacillary angiomatosis is a rare pseudoneoplastic angioproliferative lesion occurring in patients with AIDS. This condition has been associated with Bartonella henselae and Bartonella quintana infections. Human herpesvirus 8 (HHV-8) is thought to be the causative agent of Kaposi's sarcoma, a vasoproliferative neoplasm, also commonly found in patients with AIDS. The presence of HHV-8 in a cohort of patients with bacillary angiomatosis was investigated. METHODS: Eight cutaneous cases of biopsy confirmed bacillary angiomatosis were assessed for HHV-8 using standard solution phase polymerase chain reaction (PCR). RESULTS: No case of bacillary angiomatosis harboured HHV-8 DNA. CONCLUSIONS: HHV-8 was not demonstrated in the lesions of bacillary angiomatosis and therefore does not appear to play a role in the pathogenesis of this pseudoneoplastic angioproliferative disorder. This finding might be useful in the distinction of bacillary angiomatosis from Kaposi's sarcoma, because lesions from patients with Kaposi's sarcoma almost always contains HHV-8 DNA.

AIDS-Related Opportunistic Infections↗
PubMed1999

bcl-2 immunoreactivity, human papillomavirus DNA, and cervical intraepithelial neoplasia.

The aim of this study was to identify the role of bcl-2 protein expression in precancerous lesions of the cervix in patients from Johannesburg, South Africa and to correlate this expression with human papillomavirus (HPV) status. Archival cervical biopsy specimens (n = 107) of normal squamous epithelia (n = 18), pure HPV squamous epithelial lesions (n = 15), cervical intraepithelial neoplasia (CIN) I lesions (n = 17), CIN II lesions (n = 26), and CIN III lesions (n = 31) underwent bcl-2 immunohistochemical analysis with use of the streptavidin-biotin complex/horseradish peroxidase system and nonisotopic in situ hybridization for the detection of HPV DNA. Although 45 (61%) of the 74 CIN lesions demonstrated bcl-2 protein expression in the epithelia, most seemed to be in a patchy basal cell distribution, with a 1+ to 2+ intensity. Furthermore, comparison of bcl-2 immunoreaction between the low and high grades of the CIN lesions did not reveal significant differences. In addition, there was no apparent link between the presence of HPV DNA and bcl-2 expression in the CIN lesions. In contrast to previous studies that showed an increase in bcl-2 immunostaining intensity with increasing severity of CIN, only 4 (5.4%) of our 74 CIN specimens satisfied this pattern. Hence, we suggest that bcl-2 protein expression might not play a significant role in the majority of CIN lesions in this population group and that it might not correlate with HPV status.

DNA, Viral↗
PubMed1998

Motif mutation of bradykinin B2 receptor second intracellular loop and proximal C terminus is critical for signal transduction, internalization, and resensitization.

In the search for the structural elements participating in signal transduction, internalization, and resensitization of the bradykinin B2 receptor, we identified two critical motifs, one in the second intracellular loop (IC2), the other in the proximal C terminus. We previously described the contribution of tyrosines within each of the two motifs (Tyr131 and Tyr322) to signal transduction and receptor internalization (Prado, G. N., Taylor, L., and Polgar, P. (1997) J. Biol. Chem. 272, 14638-14642). Here, we investigate the effect of exchanging both tyrosine residues simultaneously for alanine, phenylalanine, or serine, termed YAYA (Y131A/Y322A), YFYF (Y131F/Y322F), and YSYS (Y131S/Y322S) receptors, respectively. All of these mutants bound bradykinin (BK) normally, with a Kd of approximately 1.1 nM. However, although phosphoinositide (PI) turnover in response to BK by Y131A and Y131S proved negligible, the YAYA mutant returned BK-activated PI turnover to wild type (WT). In contrast, PI turnover with YSYS remained unresponsive to BK. Importantly, the pattern of BK-activated arachidonate release differed markedly in the mutant receptors. For example, whereas Y131S ablated BK-activated arachidonic acid release, conversion of this mutant to YSYS returned the BK-activated receptor function to a level above that of WT. However, YAYA showed only a partial recovery from the poor BK response of Y131A. These and additional results suggest that Tyr131 and Tyr322 interact cooperatively in conjunction with at least two separate signaling functions. Given these results, a molecular model of the receptor was generated with the IC2 and the proximal C terminus in close spatial proximity. Conformations were identified to provide structural explanation for these observations. The conserved Thr137 in the IC2 was next substituted with proline (T137P) to prevent phosphorylation at this position or with aspartate (T137D) to emulate phosphorylation. The T137P mutant demonstrated no change from WT with respect to either BK-activated PI turnover or arachidonic acid release. However, the mutant exhibited a markedly reduced capacity to internalize. It also resensitized poorly. The T137D mutant lacked both BK responsive activities. However, it internalized and resensitized normally, as did WT. These final results suggest that Thr137 is functioning as a switch in termination of signal transduction and the initiation of internalization.

Amino Acid Sequence↗
PubMed1998

Characterization of mitochondrial glutaminase and amino acids at prolonged times after experimental focal cerebral ischemia.

The mitochondrial enzyme glutaminase is a significant contributor to extracellular glutamate after neuronal injury in vitro [R. Newcomb, X. Sun, L. Taylor, N. Curthoys, R.G. Giffard, Increased production of extracellular glutamate by the mitochondrial glutaminase following neuronal death, J. Biol. Chem. 272 (1997) 11276-11282.]. As a step towards characterizing the role of the enzyme in neuronal injury in vivo, glutaminase activity was measured in central and peripheral regions of the ischemic distribution in rat brain at 6, 24, and 48 h after permanent focal ischemia. Although glutaminase activity decreases in the central ischemic area, significant activity remains in peripheral areas of evolving damage, even after 24 and 48 h ischemia. Western blots show no detectable change in glutaminase molecular weight or total immunoreactivity, regardless of the degree of inactivation. Significant amounts of glutamine remain in ischemic tissue at prolonged times after focal ischemia, while reductions in tissue amounts of glutamate are highly correlated with decreases in glutaminase activity. In vivo microdialysis probes were inserted into the ischemic periphery after 24 h focal ischemia. Glutamate is significantly elevated in these dialysates. Perfusion of the glutaminase substrate glutamine and the enzyme activator phosphate results in further and specific elevations in dialysate glutamate. In sum, significant mitochondrial glutaminase activity remains in the periphery of the ischemic lesion at 24 and 48 h, where it can contribute directly to elevated extracellular glutamate. Inactivation of the glutaminase in central areas of the ischemic lesion does not involve significant proteolytic degradation, and likely involves a specific molecular event.

Amino Acids↗
PubMed1998

Role of EP2 receptors and cAMP in prostaglandin E2 regulated expression of type I collagen alpha1, lysyl oxidase, and cyclooxygenase-1 genes in human embryo lung fibroblasts.

In a recent communication, we demonstrated that prostaglandin E2 (PGE2) lowers basal while it ablates interleukin-1beta((IL-1beta) and transforming growth factor-beta (TGFbeta) upregulated lysyl oxidase (LO) mRNA levels. Correspondingly, PGE2 increases cyclooxygenase-1 (COX1) mRNA in diploid, human embryo lung fibroblasts (IMR90) [Roy et al., 19961. We now report that these actions by PGE2 are routed through cAMP via the PGE2, EP2 receptor. Among the PGE2 receptor types, the IMR90 predominantly express the EP2 mRNA. These cells also express EP3 and EP4 mRNA at comparatively low levels. Northern blot analyses show that 11-deoxy PGE1, an EP2/EP4 agonist, emulates the action of PGE2. In a similar manner to PGE2, 11-deoxy PGE1 decreases basal and TGF-beta induced type I collagen alpha1 (COL) mRNA, basal and IL-1beta induced LO mRNA while it increases COX1 mRNA. Sulprostone, an EP3/EP1 agonist, has no effect on the expression of these three genes. Forskolin, an adenylate cyclase activator, acts in a very similar manner to PGE2 or 11-deoxy PGE1. It suppresses both basal and TGF-beta induced COL mRNA levels. Both PGE2 and 11-deoxy PGE1 increase cAMP to a level comparable with forskolin. The role of the EP2 receptor in controlling collagen production is further underscored in the immortalized Rat-1 fibroblasts, derived from Fischer rat embryos, which do not express detectable EP2 mRNA. In these cells, PGE2 has little effect on COL mRNA level, whereas forskolin increases it. Furthermore, forskolin increases cAMP level in Rat-1 cells, whereas PGE2 does not. Overall, these results illustrate that much of the PGE2 action on the expression of COL, LO, and COX1 genes is mediated through the EP2 receptor and a subsequent increase in intracellular cAMP.

Alprostadil↗
PubMed1998

Mechanisms in the transcriptional regulation of bradykinin B1 receptor gene expression. Identification of a minimum cell-type specific enhancer.

To investigate the mechanisms of bradykinin B1 (BKB1) receptor gene expression, transient DNA transfection analyses of human BKB1 receptor gene promoter were performed in SV-40 transformed IMR90 cells. A positive regulatory element (PRE) located at position -604 to -448 base pair (bp) upstream of the transcription start site consistently exhibited, by far, the highest level of relative luciferase activity. A negative regulatory element, at position -682 to -604 bp, was able to completely ablate the function of the PRE. Transfection combined with deletion and mutation analyses illustrated that the PRE contains a classic, powerful enhancer. This enhancer was minimized to a 100-bp element at position -548 to -448 bp. A 78-bp fragment of negative regulatory element functioned as a silencer. Transient transfection of the enhancer construct, driven by heterologous herpes simplex thymidine kinase promoter, into a variety of cell types, showed that this enhancer presents a cell-type specific feature. In the characterization of the enhancer, motifs A (-548 to -532) and B (-483 to -477) were found to be essential for full enhancer activity. Motif D (-472 to -467) played a smaller role in enhancer activation. Gel shift and antibody supershift assays determined that an AP-1 factor binds with motif B. The nuclear protein which binds to motif A has yet to be identified. Both factors are the critical regulators for this enhancer activation.

Animals↗
PubMed1998

Method of purification affects some interfacial properties of pulmonary surfactant proteins B and C and their mixtures with dipalmitoylphosphatidylcholine.

Two methods were employed for preparation of lipid extracts from porcine lung surfactant. Pulmonary surfactant proteins SP-B and SP-C were isolated from the extracts using gel-exclusion chromatography on LH-60 with chloroform:methanol acidified with hydrochloric acid. Monolayers of pure SP-B or SP-C isolated from butanol lipid extracts spread at the air-water interface showed larger molecular areas than those determined in films of SP-B or SP-C isolated from chloroform surfactant extracts. Aqueous dispersions of dipalmitoylphosphatidylcholine (DPPC) supplemented with 2.5 and 5.0 wt% of SP-B or SP-C obtained from butanol extracts adsorbed faster to the air-water interface than their counterparts reconstituted with proteins isolated from chloroform extracts. Surface pressure-area characteristics of spread monolayers of DPPC plus SP-B or SP-C did not depend on the method of isolation of the proteins. The diagrams of the mean molecular areas vs. composition for the monolayers of DPPC plus SP-B or SP-C showed positive deviations from the additivity rule, independently of the procedure used for preparation of lipid extract surfactant. Matrix-assisted laser desorption/ionization spectrometry of the proteins isolated from different extraction solvents was consistent with some differences in the chemical compositions of SP-Bs. Butylation of SP-B during extraction of surfactant pellet with butanol may account for the differences observed in the molecular masses of SP-Bs isolated by the two different extraction protocols. The study suggests that the method of purification of SP-B and SP-C may modify their ability to enhance the adsorption rates of DPPC/protein mixtures, and this may be relevant to the formulation of protein-supplemented lipids for exogenous treatment of pulmonary surfactant insufficiency.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1998

Roles for interleukin-1beta, phorbol ester and a post-transcriptional regulator in the control of bradykinin B1 receptor gene expression.

Bradykinin B1 receptor (BKB1R) is involved in a variety of pathophysiological processes, particularly those related to inflammation. The gene for this receptor is known to be upregulated by interleukin (IL)-1beta, a proinflammatory cytokine. However, the molecular mechanisms involved in the regulation of the BKB1R gene expression have not been defined. We demonstrated that IL-1beta induces a rapid increase in BKB1R mRNA level and the binding of desArg10-kallidin in human embryo lung fibroblasts (IMR90). This increase in BKB1R mRNA level is protein synthesis-independent as indicated by treatment of cells with cycloheximide (CHX) or puromycin (PUR). By testing the IL-1beta effect on BKB1R mRNA degradation, we showed that the IL-1beta upregulation of BKB1R expression is achieved through both transcriptional activation and post-transcriptional mRNA stabilization. In addition to the IL-1beta effects, translation inhibitors, CHX and PUR increase the steady state BKB1R mRNA level by inhibiting BKB1R mRNA degradation. Removal of the CHX block with subsequent resumption of protein synthesis results in a sizable increase of desArg10-kallidin binding. Using signalling pathway inhibitors, we show that IL-1beta functions through a protein tyrosine kinase, not protein kinase C or protein kinase A. However, activation of protein kinase C by phorbol 12-myristate 13-acetate increases the level of BKB1R mRNA and the binding of desArg10-kallidin. This increase is blocked by NF-kappaB activation inhibitors.

Cell Line↗
PubMed1998

Microfabricated device coupled with an electrospray ionization quadrupole time-of-flight mass spectrometer: protein identifications based on enhanced-resolution mass spectrometry and tandem mass spectrometry data.

We describe the coupling of a microfabricated fluidic device to an electrospray ionization (ESI) quadrupole time-of-flight mass spectrometer (QqTOFMS) for the identification of protein samples. The microfabricated devices consisted of three reservoirs connected via channels to a main capillary, which in turn was linked via a microspray interface to the QqTOFMS. Here we present preliminary results obtained using this system. Standardized solutions of myoglobin tryptic digest were analyzed indicating a limit of detection at the low to sub fmol/microL. The combination of the microfabricated device for rapid sample delivery and the rapid acquisition capability, enhanced resolution and mass accuracy of the QqTOF offers unique possibilities for the rapid identification of proteins by database searching. This platform can generate MS data suitable for protein database searching by the peptide-mass fingerprinting approach and MS/MS data suitable for protein database searching. Here the results of the two database-searching approaches are compared and the possibilities of combining the two approaches for rapid identification of protein are discussed. Also, we present a comparison of the results obtained using the three-position microfabricated device coupled to the ESI-QqTOFMS and to an ESI-ion trap MS. Finally the combination of C-terminal 18O labeling of peptides and the microfabricated system for automated combined peptide-mass fingerprinting and sequence-tag database searching is discussed.

Databases, Factual↗