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At least 973 records · Page 54Linked to original sources
PubMed2005

Direct quantification of protein partitioning in oil-in-water emulsion by front-face fluorescence: avoiding the need for centrifugation.

The quantification of proteins adsorbed at the oil-in-water interface is often difficult since it requires separation of fat globules from the aqueous phase that may damage the fat globule size and/or modify the interfacial composition. Front-face fluorescence spectroscopy was used to characterize the protein partitioning between the aqueous and oil phases of emulsions without separating these two phases. Different emulsions based on skim milk powder (SMP), two mono- and di-glyceride (MDG) mixtures (saturated and partially unsaturated), and three fats (hydrogenated and refined coconut oils and refined palm oil) were studied. The impact of an ageing period (24 h at 4 degrees C) was also investigated to typify the first step of ice cream processing. The emulsions were characterized for protein partitioning, immediately following emulsification and after ageing, using the Bradford spectrophotometric method, applied to the aqueous phase recovered after emulsion centrifugation. In parallel, the emulsions were characterized by their tryptophan emission fluorescence spectra. The area of the peaks at 333 nm, of the fourth-derivative fluorescence spectra corresponding to the amount of proteins present in the aqueous phase of emulsions, was well correlated with the Bradford measurements (r2=0.91). This amount was also calculated from the fluorescence calibration curve obtained with SMP in solution. In conclusion, front-face fluorescence spectroscopy appeared to be a powerful and simple technique allowing the quantification of different populations of protein in an emulsified system, i.e., in the aqueous phase and loaded at the fat globule interface.

Centrifugation↗
PubMed2006

IVME: a tool for editing, manipulation, quantification, and labeling of cerebrovascular models.

Three-dimensional (3D) vascular models are important in medical education, interventional radiology and vascular surgery. Because of a limited quality of angiographic images and inaccuracies introduced during their processing, interactive enhancement of the resulting models is required. We introduce here a novel tool, the interactive vascular modeling environment (IVME) for editing, manipulation, quantification, and labeling of cerebrovascular models. We describe the IVME architecture and design along with the functionality supporting anatomy terminology linking, 2D and 3D labeling, editing, 2D-3D cross-referencing, measurements, and quantification. The IVME is a useful platform in education, research, and clinics to explore and manipulate the angiography data in 2D and 3D.

Cerebral Angiography↗
PubMed2005

Validation of real-time RT-PCR assays for mRNA quantification in baboons.

Real-time RT-PCR has been used widely, both in fundamental research and in clinical diagnostics, for instance for quantification of RNA levels in human tissues and tissue biopsies. In the present study we provide a strategy to validate primers/probes for real-time RT-PCR quantification of baboon samples. The method is based on the TaqMan system and uses primers/probes that have been designed and validated for human real-time RT-PCR. A prerequisite for the accuracy of this strategy is a similar amplification efficiency between human and baboon PCR reactions. We propose two different methods, i.e. by calculating PCR efficiencies from the slope of a dilution curve or by using the linear regression method, to compare the amplification efficiency between human and baboon samples. In conclusion, by performing a simple validation experiment, real-time PCR assays based on human sequences, which are easily available, can be applied for analysis of baboon samples.

Animals↗
PubMed2006

Quantification of myocardial perfusion using intravenous myocardial contrast echocardiography in healthy volunteers: comparison with positron emission tomography.

BACKGROUND: Intravenous myocardial contrast echocardiography (ivMCE) has the potential to evaluate myocardial contraction and perfusion simultaneously. The purpose of this study was to assess quantification of myocardial blood flow (MBF) using ivMCE and to compare this with MBF as measured with positron emission tomography (PET). METHODS: A total of 16 healthy volunteers underwent ivMCE using power pulse inversion and contrast agent microbubbles at rest and during pharmacologically induced vasodilation. Microbubble destruction was achieved with a burst of high-energy ultrasound, followed by imaging of contrast replenishment with low-energy ultrasound. Regions of interest were drawn and time intensity curves were calculated that were fitted to a monoexponential function. An estimate of MBF (perfusion estime) was calculated as the product of the plateau value A and the exponential beta describing the replenishment curve. MBF was measured with PET using oxygen-15-labeled water at rest and during adenosine stress. RESULTS: Significant correlations were found between MBF as measured with PET and perfusion estimate as measured with ivMCE in the left anterior descending coronary artery (r = 0.87, P < .01), right coronary artery (r = 0.66, P < .01), and left circumflex artery (r = 0.75, P < .01) territories. Heterogeneity, however, was significantly larger for ivMCE (coefficient of variation 32 +/- 15%) than for PET (9 +/- 6%) measurements (P < .01). CONCLUSION: Perfusion parameters as measured with ivMCE correlated with PET-derived MBF, but associated heterogeneity was significantly larger. Currently, this heterogeneity precludes true quantification of MBF using ivMCE.

Adult↗
PubMed2006

Quantification of regional left ventricular wall motion from real-time 3-dimensional echocardiography in patients with poor acoustic windows: effects of contrast enhancement tested against cardiac magnetic resonance.

OBJECTIVE: Regional left ventricular function can be assessed by real-time 3-dimensional echocardiography (RT3DE) in patients with good image quality. Our goals were to: (1) test the feasibility of RT3DE quantification of regional wall motion (RWM) in patients with poor acoustic windows who require contrast for endocardial visualization; and (2) validate these measurements against cardiac magnetic resonance (CMR) reference. METHODS: RT3DE datasets and CMR images were obtained in 24 patients. In 16 of 24 patients with suboptimal endocardial definition, RT3DE imaging was repeated with intravenous contrast and triggering at end systole and end diastole. RT3DE datasets were analyzed using custom software designed to semiautomatically detect and segment the endocardial surface and calculate RWM values. CMR images were analyzed using commercial software to obtain reference values for RWM. RESULTS: In 8 of 24 patients with good endocardial definition, RT3DE values of RWM correlated well with CMR (r = 0.73) with a small bias (-1.0 mm). In the remaining 16 patients, analysis of nonenhanced RT3DE datasets yielded lower correlation with CMR (r = 0.61) and a slightly greater bias (-1.5 mm). The agreement with CMR improved significantly (r = 0.76, bias -1.1 mm) with contrast enhancement. CONCLUSIONS: The agreement between RT3DE and CMR values of RWM is directly related to RT3DE image quality. In patients with poor acoustic windows, dual-triggered contrast enhancement improves the accuracy of RWM quantification to a level similar to that noted in patients with good images without contrast.

Computer Systems↗
PubMed2005

Endothelial cell apoptosis in the context of quantification of angiogenesis in solid human adenocarcinomas: a novel double immunolabelling technique to identify endothelial cell apoptosis.

Standardised methods of microvessel density quantification have been published. However, a reliable and reproducible method to visualise endothelial cell apoptosis is lacking, which is a shortcoming in assessing vascular remodelling during angiogenesis. The aim of this study was to validate a newly developed technique to demonstrate endothelial cell apoptosis by double immunolabelling with anti-CD34 and anti-activated caspase-3 in human adenocarcinomas. Double immunolabelling was used to identify apoptotic endothelial cells in six tumours of eight different human adenocarcinomas. Microvessel density and rate of apoptotic endothelial cells were quantified. The technique revealed endothelial cell apoptosis simultaneously with the identification of microvessel density on one slide. These characteristics were reproducible in adenocarcinomas of various sites. In conclusion, apoptotic endothelial cells and microvessel density can now be evaluated simultaneously within one and the same area, allowing a more reliable histological quantification of angiogenesis.

Adenocarcinoma↗
PubMed2004

MRI measurements of water diffusion: impact of region of interest selection on ischemic quantification.

OBJECTIVE: To investigate the effect of ADC heterogeneity on region of interest (ROI) measurement of isotropic and anisotropic water diffusion in acute (< 12 h) cerebral infarctions. METHODS AND MATERIALS: Full diffusion tensor images were retrospectively analyzed in 32 patients with acute cerebral infarction. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured in ischemic lesions and in the corresponding contralateral, normal appearing brain by using four ROIs for each patient. The 2 x 2 pixel square ROIs were placed in the center, the lateral rim and the medial rim of the infarction. In addition, the whole volume of the infarction was measured using a free hand method. Each ROI value obtained from the ischemic lesion was normalized using contralateral normal ROI values. RESULTS: The localization of the ROIs in relation to the ischemic lesion significantly affected ADC measurement (P < 0.01, using Friedman test), but not FA measurement (P = 0.25). Significant differences were found between ADC values of the center of the infarction versus whole volume (P < 0.01), and medial rim versus whole volume of infarction (P < 0.001) with variation of relative ADC values up to 11%. The differences of absolute ADC for these groups were 22 and 23%, respectively. The lowest ADC was found in the center, followed by medial rim, lateral rim and whole volume of infarction. CONCLUSION: ADC quantification may provide variable results depending on ROI method. The ADC and FA values, obtained from the center of infarction tend to be lower compared to the periphery. The researchers who try to compare studies or work on ischemic quantification should be aware of these differences and effects.

Adolescent↗
PubMed2005

Quantification of mitochondrial DNA using real-time polymerase chain reaction in patients with premature ovarian failure.

OBJECTIVE: To quantify mitochondrial DNA using real-time PCR in women with premature ovarian failure (POF) and a control group. DESIGN: Prospective study. SETTING: Genome Research Center for Reproductive Medicine and Infertility, Korea Ministry of Health & Welfare. PATIENT(S): Thrity patients with POF and 30 control individuals. INTERVENTION(S): The mitochondrial DNA content was quantified using real-time PCR. The effectiveness of the assay was determined by relative quantification using the comparative threshold cycle (CT) method. MAIN OUTCOME MEASURE(S): Relative quantification of mitochondrial DNA content. RESULT(S): The mitochondrial DNA content was significantly lower in the POF group than in the control group (0.58 +/- 0.38 vs. 1.15 +/- 0.67; P < .01). In both groups, there was a significant positive correlation between the mitochondrial DNA/28S rRNA ratio and mitochondrial DNA CT (control group: r = 0.774; P < .001; POF group: r = 0.556; P = .001) and a significant negative correlation between the mitochondrial DNA/28S rRNA ratio and 28S rRNA CT (control group: r = -0.677; P < .001; POF group: r = -0.627; P = .001). CONCLUSION(S): This study has established the clinical feasibility of quantifying amounts of mitochondrial DNA, relative to an internal standard, using real-time PCR. Further studies are warranted to elucidate the roles of apoptosis and mitochondrial function in the pathogenesis of POF.

Adult↗
PubMed2004

Identification and quantification of N(epsilon)-(Hexanoyl)lysine in human urine by liquid chromatography/tandem mass spectrometry.

The identification and quantification of N(epsilon)-(hexanoyl)lysine (N(epsilon)-HEL), which was found from the reactions between lipid hydroperoxide and lysine, from human urine was examined using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The N(epsilon)-HEL in the partially purified urine fraction was identified using LC/MS/MS by several approaches including precursor/product ion scans. The peak found by the multiple-reaction monitoring (MRM) of the collision-induced fragmentation of N(epsilon)-HEL was clearly observed in urine, and the elution position coincided with the synthetic standard N(epsilon)-HEL. The product, estimated N(epsilon)-HEL, was absorbed by a specific antibody to N(epsilon)-HEL. Moreover, N(alpha)-HEL, one of the plausible hexanoyl adducts from the reaction between the N(alpha) moiety of L-lysine and the peroxidized lipid, was hardly detected in urine samples, suggesting that the origin of the N(epsilon)-HEL is the peroxidized lipid-modified proteins but not artificial hexanoylated L-lysine. Using the MRM technique, the amount of urinary N(epsilon)-HEL from the control subjects (observed healthy) was estimated to be 1.58 +/- 0.23 mumol/mol of creatinine. A comparative study of the urinary N(epsilon)-HEL with an oxidative stress marker, 8-oxo-7,8-dihydro-2'-deoxyguanosine, showed a high correlation (r = 0.844) between the two biomarkers. Furthermore, the quantification of N(epsilon)-HEL in the control and diabetic urines revealed that the urinary N(epsilon)-HEL from diabetic subjects (3.21 +/- 0.65 mumol/mol of creatinine) was significantly higher than that from the control subjects.

Antibodies↗
PubMed2006

Comparing diffusion-weighted and T2-weighted MR imaging for the quantification of infarct size in a neonatal rat hypoxic-ischemic model at 24h post-injury.

PURPOSE: In a neonatal rat model of hypoxic-ischemic (HI) brain injury, using T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), we aim to determine the best MRI method of lesion quantification that reflects infarct size. MATERIALS AND METHODS: Twenty 7-day-old rats underwent MRI 24h after HI brain injury was induced. Lesion size relative to whole brain was measured using T2WI and apparent diffusion coefficient (ADC) maps, applying thresholds of 60%, 70% and 80% contralateral control hemisphere mean ADC, and at day 10 post-HI on pathology with TTC staining. Multiple linear regression analysis was used to study the relationships between lesion size at MRI and pathology. RESULTS: Lesion size measurement using all MRI methods significantly correlated with infarct size at pathology; using T2WI, r=0.808 (p<0.001), using 80% ADC, 70% ADC and 60% ADC thresholds, r=0.888 (p<0.001), 0.761, (p<0.001) and 0.569 (p=0.014), respectively. Eighty percent ADC threshold was found to be the only significant independent predictor of final infarct volume (adjusted R(2)=0.775). CONCLUSION: At 24h post-HI, lesion size on DWI, using 80% ADC threshold is the best predictor of final infarct volume. Although T2WI performed less well, it has the advantage of superior spatial resolution and is technically less demanding. These are important considerations for experiments which utilize MRI as a surrogate method for lesion quantification in the neonatal rat HI model.

Animals↗
PubMed2005

A rapid chemiluminescent slot blot immunoassay for the detection and quantification of Clostridium botulinum neurotoxin type E, in cultures.

A simple, rapid, cost-effective in vitro slot blot immunoassay was developed for the detection and quantification of botulinum neurotoxin type E (BoNT/E) in cultures. Culture supernatants of 36 strains of clostridia, including 12 strains of Clostridium botulinum type E, 12 strains of other C. botulinum neurotoxin serotypes, and 12 strains of other clostridial species were tested. Samples containing BoNT/E were detected using affinity-purified polyclonal rabbit antisera prepared against BoNT/E with subsequent detection of secondary antibodies using chemiluminescence. All strains of C. botulinum type E tested positive, while all non C. botulinum type E strains tested negative. The sensitivity of the slot blot immunoassay for detection of BoNT/E was approximately four mouse lethal doses (MLD). The intensity of chemiluminescence was directly correlated with the concentration of BoNT/E up to 128 MLD, allowing quantification of BoNT/E between 4 and 128 MLD. The slot blot immunoassay was compared to the mouse bioassay for detection of BoNT/E using cultures derived from fish samples inoculated with C. botulinum type E, and cultures derived from naturally contaminated environmental samples. A total of 120 primary enrichment cultures derived from fish samples, of which 103 were inoculated with C. botulinum type E, and 17 were uninoculated controls, were assayed. Of the 103 primary enrichment cultures derived from inoculated fish samples, all were positive by mouse bioassay, while 94 were also positive by slot blot immunoassay, resulting in a 7.5% false-negative rate. All 17 primary enrichment cultures derived from the uninoculated fish samples were negative by both mouse bioassay and slot blot immunoassay. A total of twenty-six primary enrichment cultures derived from environmental samples were tested by mouse bioassay and slot blot immunoassay. Of 13 primary enrichment cultures positive by mouse bioassay, 12 were also positive by slot blot immunoassay, resulting in a 3.8% false-negative rate. All 13 primary enrichment cultures that tested negative by mouse bioassay also tested negative by slot blot immunoassay. The slot blot immunoassay could be used routinely as a positive screen for BoNT/E in primary enrichment cultures, and could be used as a replacement for the mouse bioassay for pure cultures.

Animal Testing Alternatives↗
PubMed2005

Prognostic significance of DNA quantification by flow cytometry in ovarian tumors.

OBJECTIVE: The objective of our study is to evaluate prognostic significance of DNA quantification by flow cytometry in ovarian tumor. METHODS: A prospective analysis was performed on 56 ovarian tumor patients treated in the Yonsei Medical Center from Feb. 2000 to Jan. 2003. RESULTS: Regarding the association between tumor grade and the DNA quantitative analysis, as tumor grade increased, the quantity of aneuploid cells and S-phase fraction (SPF) increased. In addition, SPF was increased significantly in the advanced staged patients (P=0.04) and SPF was significantly increased in aneuploid tumors (P=0.03). The overall survival rate was poor for patients with aneuploid tumors and for patients with tumors showing over SPF (10%). CONCLUSION: Our data demonstrated that the prognosis was poor for patients with aneuploid cancers or increased SPF. Therefore, DNA quantification by flow cytometry may provide important information for predicting the prognosis of the disease.

Aneuploidy↗
PubMed2005

The effect of the antibody used and method of quantification on oral mucosal vascularity.

A vast literature exists on angiogenesis particularly with regard to understanding tumour growth and development. This is no less true for oral cancer, where slight variations in protocols may invalidate comparison between studies. The influence of tissue processing, and the specific antibody and method of quantification used to identify blood vessels was assessed with respect to oral mucosal vascularity. The angiogenic profile of 20 frozen sections of clinically normal oral mucosa were compared with 16 paraffin-embedded specimens. Eight of the frozen specimens had matched paraffin-embedded tissue. Vascular antigens were identified immunohistochemically using four antibodies and blood vessel density was measured by three methods. CD31 and von Willebrand's factor (vWF) counts were higher than alpha-smooth muscle actin and alphanubeta3. Results for CD31 were higher in frozen tissue than paraffin-embedded tissue. Significantly more CD31-positive vessels were found in frozen tissue in the cohort of matched samples. For paraffin-embedded tissue vWF gave higher values for vascularity than CD31. The variation in antibody reaction to these markers of blood vessels suggests that the antibody employed and method of fixation is more important than the method of quantification used. Comparison of the results for fresh frozen tissue and paraffin-processed tissue suggests that this is acceptable for vWF but not for CD31.

Actins↗
PubMed2004

New protamine quantification method in microtiter plates using o-phthaldialdehyde/N-acetyl-L-cysteine reagent.

Protamine is a well-known excipient in pharmaceutics. It represents a peptide consisting of exclusive aliphatic amino acids, hence it cannot be quantified by UV-spectroscopy (lambdamax 280 nm). A new and sensitive quantification method based on the derivatisation of protamine with ortho-phthaldialdehyde (OPA) in the presents of 2-mercaptoethanol (ME) or N-acetyl-L-cysteine (NAC) in basic aqueous solution using 96-well microtiter plates are introduced in this report. The resulting isoindol derivatives reveal a fluorescence excitation (maximum lambdaex 345 nm) and emission (maximum lambdaem 450 nm) spectra. Derivatives of OPA/NAC reagent were found to be useful for protamine quantification in pharmaceutical nanoparticle preparation containing DNA. A sufficient stability of the isoindol derivatives was shown. It was possible to determine protamine free base, protamine sulphate and protamine chloride with limits of detection less than 1.1 microg/ml.

Acetylcysteine↗
PubMed2005

Quantification of low levels of amorphous content in sucrose by hyperDSC.

A method was developed for the quantification of low levels of amorphous content in sucrose with hyperDSC. The method was based on the fact that the change of specific heat at the glass transition is linearly proportional to the amorphous content. It was found out that as annealing time increased, the glass transition temperature moved to a higher temperature and the change of specific heat increased. DeltaC(p) for annealed totally amorphous sucrose was 0.761+/-0.012 Jg(-1) degrees C(-1). Synthetic mixtures with various proportions of crystalline and amorphous sucrose were prepared. The following linear regression between DeltaC(p) and amorphous content was obtained: DeltaC(p)=0.0075x - 0.00484 (R=0.999). The limit of detection (LOD) and the limit of quantification (LOQ) values were 0.062 and 0.207%, respectively. The effect of grinding time on the amorphous content of crystalline sucrose was studied and a correlation between grinding time and amorphous content of sucrose was found. It was also found that the amorphous content could only attain a value of about 80-90% by grinding in the way used in this study.

Calorimetry, Differential Scanning↗
PubMed2005

Broad-beam spectral Doppler sonification of the vena contracta using matrix-array technology: A new solution for semi-automated quantification of mitral regurgitant flow volume and orifice area.

OBJECTIVES: The objective of this study was to evaluate broad-beam spectral Doppler sonification of the vena contracta using a matrix-array transducer for quantification of mitral regurgitation (MR). BACKGROUND: Noninvasive assessment of the severity of valvular regurgitation remains challenging. A recent technique measures regurgitant flow directly at the vena contracta based on the product of velocity times backscattered Doppler power (proportional to orifice area). That approach, however, has been limited by relatively narrow conventional beamwidths. Matrix-array transducers, recently developed for three-dimensional imaging, can potentially provide broader beams. Therefore, we addressed the hypothesis that deliberate broadening of the Doppler beam can encompass larger regurgitant cross-sectional areas to capture a broader range of regurgitant flows. METHODS: A matrix-array transducer system was modified to provide a three-dimensionally expanded spectral Doppler sample volume. Calculations of orifice area, flow rate, and regurgitant stroke volume (RSV) from Doppler power were automated on board a routinely used echocardiographic scanner and tested in vitro. In 24 patients with isolated MR, RSV was compared with magnetic resonance imaging (MRI) mitral inflow minus aortic outflow from phase-velocity maps. RESULTS: The calculated flow rate and RSV correlated and agreed well with reference values in vitro (r = 0.98 to 0.99) and in patients (r = 0.93, mean difference 0.4 +/- 3.2 ml, p = NS vs. 0), with sufficient sonification to measure flow orifices up to 0.85 cm in diameter. Agreement with MRI was comparable in 17 patients with central and seven with eccentric jets (p = NS vs. 0). CONCLUSIONS: The broad-beam spectral Doppler technique provides accurate, largely automated quantification of regurgitant flow rate and integrated RSV directly at the lesion. The accuracy related to broader sonification is made possible by the new matrix-array transducer design.

Adult↗
PubMed2004

Human monoclonal antibody-based quantification of group 2 grass pollen allergens.

BACKGROUND: Grasses belong to the most potent allergen sources worldwide. Group 2 grass pollen allergens are recognized by more than 100 million allergic patients. OBJECTIVE: The aim was to develop an assay for the specific detection and quantification of group 2 grass pollen allergens. METHODS: We have isolated a monoclonal human IgE Fab specific for group 2 grass pollen allergens by combinatorial cloning from lymphocytes of a grass pollen-allergic patient. This Fab was converted into a complete human IgG1 antibody and used together with rPh1 p 2 to develop a competitive ELISA for the specific measurement of group 2 allergens. ELISA plate-bound purified recombinant human Ph1 p 2-specific IgG1 is incubated with a constant amount of biotinylated rPh1 p 2 competing with increasing concentrations of group 2 allergens to be determined. Defined concentrations of purified rPhl p 2 are used to establish a standard curve. The concentration of unlabeled group 2 allergens can thus be deduced from the displacement of biotinylated rPh1 p 2, which can be detected with peroxidase-labeled streptavidin. RESULTS: The competition-ELISA measured rPh1 p 2 concentrations ranging from 10 ng/mL to 500 ng/mL and allowed to quantify group 2 allergens from 9 different grass families. The results were in good agreement with immunoblot data. CONCLUSIONS: The described assay can be used for standardization of diagnostic and therapeutic vaccines as well as for the quantification of group 2 allergens in environmental samples.

Allergens↗
PubMed2006

Quantification of phosphorylation of insulin receptor substrate-1 by HPLC-ESI-MS/MS.

Serine/threonine phosphorylation of insulin receptor substrate-1 (IRS-1) regulates the function and subsequent insulin signaling of this protein. Human IRS-1 has 1242 amino acid residues, including 182 serines and 60 threonines. The size, complexity, and relatively low abundance of this protein in biological samples make it difficult to map and quantify phosphorylation sites by conventional means. A mass spectrometry peak area based quantification approach has been developed and applied to assess the relative abundance of IRS-1 phosphorylation in the absence or presence of stimuli. In this method, the peak area for a phosphopeptide of interest is normalized against the average of peak areas for six selected representative IRS-1 peptides that serve as endogenous internal standards. Relative quantification of each phosphopeptide is then obtained by comparing the normalized peak area ratios for untreated and treated samples. Two non-IRS-1 peptides were added to each digest for use as HPLC retention time markers and additional standards as well as references to the relative quantity of IRS-1 in different samples. This approach does not require isotopic or chemical labeling and can be applied to various cell lines and tissues. Using this method, we assessed the relative changes in the quantities of two tryptic phosphopeptides isolated from human IRS-1 expressed in L6 cells incubated in the absence or presence of insulin or tumor necrosis factor-alpha. Substantial increases of phosphorylation were observed for Thr(446) upon stimulation. In contrast, no obvious change in the level of phosphorylation was observed for Ser(1078). This mass spectrometry based strategy provides a powerful means to quantify changes in the relative phosphorylation of peptides in response to various stimuli in a complex, low-abundance protein.

Amino Acid Sequence↗