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PubMed2003

Developmental transition from gavage to oral feeding in the preterm infant.

The development of early oral feeding skills in the preterm infant is an active and complex area of nursing research. This integrative review summarizes the accumulated nursing research since 1990 that describes feeding the preterm infant during the transition from gavage to full oral feeding. Literature was identified through searches of databases covering the fields of nursing and medicine and of journals and nurse researchers who publish in this area of study. Four main areas of research were identified: development of infant feeding skills, descriptive studies on the transition period, studies that focus on identifying infant readiness to begin oral feeding, and studies that explore optimal ways to advance oral feeding as the infant moves toward full oral feeding. Research studies were critiqued from a developmental science perspective, which conceptualizes feeding skill as an emergent property of multiple systems, both within and outside the infant, that are interacting and working together to promote optimal functioning. Through this analysis, areas for future research are identified.

Bottle Feeding↗
PubMed1997

An European concerted action investigating the validity of perinatal mortality as an outcome indicator for the quality of antenatal and perinatal care.

In this paper the concepts, objectives, design, and data analysis procedures of the EuroNatal study are described. This study started in 1996 and is a concerted action including 14 countries in Europe. The EuroNatal study aims at determining the validity of national perinatal mortality rates as an outcome indicator for the quality of antenatal and perinatal care. It is based on a conceptual model describing the relationships between differences in quality of antenatal and perinatal care, maternal and infant risk factors, variation in applied definitions, reliability of registration procedures and practices, and the outcome in terms of "true" and "observed" differences in perinatal mortality. In the first part of the study data is collected at national and aggregate level; in the second part data is collected retrospectively on individual cases of perinatal mortality in a regional sample area. Analysis of the individual cases of perinatal mortality will be by means of a perinatal audit conducted by an international expert panel. The project builds upon the work done by the participants in their respective countries. By applying common research protocols, international comparability of data collection will be enhanced and will help to create a common body of knowledge in the area of perinatal epidemiology and perinatal care. Comparison between countries is likely to lead to new insights into the strengths and weaknesses of antenatal and perinatal care systems of individual countries.

Europe↗
PubMed1995

The particle size distribution, density, and specific surface area of welding fumes from SMAW and GMAW mild and stainless steel consumables.

Particle size distributions were measured for fumes from mild steel (MS) and stainless steel (SS); shielded metal arc welding (SMAW) and gas metal arc welding (GMAW) consumables. Up to six samples of each type of fume were collected in a test chamber using a micro-orifice uniform deposit (cascade) impactor. Bulk samples were collected for bulk fume density and specific surface area analysis. Additional impactor samples were collected using polycarbonate substrates and analyzed for elemental content. The parameters of the underlying mass distributions were estimated using a nonlinear least squares analysis method that fits a smooth curve to the mass fraction distribution histograms of all samples for each type of fume. The mass distributions for all four consumables were unimodal and well described by a lognormal distribution; with the exception of the GMAW-MS and GMAW-SS comparison, they were statistically different. The estimated mass distribution geometric means for the SMAW-MS and SMAW-SS consumables were 0.59 and 0.46 micron aerodynamic equivalent diameter (AED), respectively, and 0.25 micron AED for both the GMAW-MS and GMAW-SS consumables. The bulk fume densities and specific surface areas were similar for the SMAW-MS and SMAW-SS consumables and for the GMAW-MS and GMAW-SS consumables, but differed between SMAW and GMAW. The distribution of metals was similar to the mass distributions. Particle size distributions and physical properties of the fumes were considerably different when categorized by welding method. Within each welding method there was little difference between MS and SS fumes.

Aerosols↗
PubMed2004

Survival chances and psychological aspects of quality of life in patients with localized early stage breast cancer.

BACKGROUND: The present analysis focuses on the long term psychological reactions to early stage breast cancer. Two hypotheses were formulated. The first hypothesis draws a direct link between tumour size/survival chances and Quality of life (QoL): The better the survival chances, the better QoL ('biological danger model'). The second hypothesis assumes that localized early breast cancer has excellent prognosis (> 90% five year survival rate), and that therefore QoL differences between various forms of early breast cancer should be minimal ('medico-pragmatic model'). PATIENTS AND METHODS: In a defined rural area with 252.000 inhabitants (small-area-analysis), a total of n = 389 patients with primary breast cancer were recruited. For the present analysis we selected a subgroup (n = 269) from the cohort by tumour size (pTis, pT1a,b, pT1c, and pT2). QoL scores for global quality of life, emotional functioning and future perspective were computed according to the EORTC manual and compared to age-matched norm data of the German population. RESULTS: A total of 690 QoL questionnaires were obtained from n = 269 patients with comparable completion rates within the four subgroups (pTis, pT1a,b, pT1c, and pT2). For all four groups and in all scores there were improvements over time. Generally, pTis always scored highest, pT2 always lowest, the other two groups in between. After one year pTis patients had higher mean scores in global quality of life than the norm. In contrast, pT1a,b were considerably lower than the norm and the difference between these two was 17.2 score points. It seems that the small difference (3.5%) in five year survival chances between pTis and T1 a,b tumours transforms into marked differences regarding quality of life, thus supporting a biological danger model of the survival/QoL relationship. CONCLUSIONS: Our results show that physicians have to realise although their early breast cancer patients have excellent survival chances, psychological distress is present. From a clinical perspective we would recommend that early stage breast cancer patients, and especially patients with occult, pT1a,b tumours be informed about their excellent prognosis. In addition, cognitive therapy might help patients stop worrying about their cancer.

Breast Neoplasms↗
PubMed2005

Differentiation of spores of Bacillus subtilis grown in different media by elemental characterization using time-of-flight secondary ion mass spectrometry.

We demonstrate the use of time-of-flight secondary ion mass spectrometry (TOF-SIMS) in a forensics application to distinguish Bacillus subtilis spores grown in various media based on the elemental signatures of the spores. Triplicate cultures grown in each of four different media were analyzed to obtain TOF-SIMS signatures comprised of 16 elemental intensities. Analysis of variance was unable to distinguish growth medium types based on 40Ca-normalized signatures of any single normalized element. Principal component analysis proved successful in separating the spores into groups consistent with the media in which they were prepared. Confusion matrices constructed using nearest-neighbor classification of the PCA scores confirmed the predictive utility of TOF-SIMS elemental signatures in identifying sporulation medium. Theoretical calculations based on the number and density of spores in an analysis area indicate an analytical sample size of about 1 ng, making this technique an attractive method for bioforensics applications.

Bacillus subtilis↗
PubMed2000

Prediction of outcome by computer-assisted analysis of lung area on the chest radiograph of infants with congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Pulmonary hypoplasia is a major cause of mortality and morbidity in infants with congenital diaphragmatic hernia (CDH). Pulmonary hypoplasia is characterized by low volume lungs, and affected infants are likely to have a low lung area on their chest radiograph. The authors assessed whether, in CDH infants, computer-assisted analysis of the chest radiograph lung area gave an accurate indication of lung volume, and if a low lung area was a better predictor of poor outcome (death or oxygen dependency at 28 days) than other test results. METHODS: Comparisons were made of the radiographic lung area derived by computer-assisted analysis and lung volume, assessed by measurement of functional residual capacity (FRC) on day 1 before surgical intervention and on the first postoperative day. Compliance was measured, and the maximum and modified ventilation indices and maximum Paco2 also was noted. Twenty-five CDH infants with a median gestational age of 38 weeks were studied; 18 had FRC measurements preoperatively. RESULTS: Both preoperatively and postoperatively, the lung areas and FRCs correlated significantly (r = 0.51, P<.05; r = 0.76, P<.02, respectively). Eleven infants had a poor outcome (5 infants died without an operation); that group preoperatively differed significantly from those with a good outcome with respect to having a lower compliance (P<.02) and higher maximum ventilation index (P<.01) and maximum modified ventilation index (P<.05). Only postoperatively did infants with a poor outcome versus good outcome have a significantly lower lung area (P<.05); they also had a lower increase in lung area preoperatively to postoperatively (P<.01). Receiver operator characteristic curves were constructed; comparison of the areas under the curves showed that preoperatively, a low compliance and high ventilation index were the best predictors of poor outcome. Postoperatively, a low lung area performed as well as the ventilation indices. CONCLUSION: Computer-assisted analysis of the lung area on the chest radiograph is useful in predicting outcome in CDH infants postoperatively but not preoperatively.

Hernia, Diaphragmatic↗
PubMed2026

Identification of Immune Response-Related Proteomic Biomarkers in Moyamoya Disease Using Serum Olink Proteomics.

Moyamoya disease, a rare chronic cerebrovascular disorder, requires invasive digital subtraction angiography (DSA) for diagnosis. This study employed high-throughput proteomics to identify plasma biomarkers for Moyamoya disease diagnosis. We conducted immunopanel analysis using the Olink platform to evaluate 92 immune-related proteins in plasma samples from 88 Moyamoya disease patients and 88 healthy controls. Key proteins were identified through differential expression analysis, GO, and KEGG enrichment analysis. A diagnostic model was constructed using LASSO regression, Boruta algorithm, and machine learning models including random forest and XGBoost. Validation of these proteins was performed using GEO external data sets, followed by prediction of potential therapeutic drugs and molecular docking validation through pharmacogenomic databases. A total of 44 differentially expressed proteins were identified through the Olink immunopanel, with 12 downregulated and 32 upregulated. GO and KEGG analyses revealed significant enrichment of these proteins in innate immune responses and signaling pathways such as NF-kB and MAPK. Through LASSO, random forest, and protein under-area analysis, four potential biomarkers for Moyamoya disease (MGMT, SIT1, PRDX1, TRAF2) were identified. A diagnostic model using these proteins showed the highest AUC value with the XGBoost model. Additionally, TRAF2 and PRDX1 exhibited significant expression differences in Moyamoya disease patients within the GEO data set. Our study revealed the immune landscape of Moyamoya disease, identified four biomarkers, and established a variety of diagnostic models.

Humans↗
PubMed1999

[Assessment of regional myocardial function by ECG-gated myocardial SPECT].

PURPOSES: Regional myocardial functional parameters were assessed by ECG-gated myocardial SPECT analysis in normal subjects and ischemic heart diseases. METHODS: Normal subjects (13 male and 10 female) and 51 patients with chronic ischemic heart disease underwent ECG-gated myocardial SPECT. A dose of 740 MBq of 99mTc-MIBI was injected at rest, and gated SPECT was performed 60 min later. Wall motion (WM) and systolic wall thickening (WT), % tracer uptake were evaluated by quantitative gated SPECT program (QGS). Regional parameters were obtained in the 16 segments based on the functional polar map. In the normal group, standard values were evaluated in the lateral, septal, anterior and inferior regions both in male and female subjects. In the ischemic heart disease group, sensitivity and specificity of these parameters were assessed in each segment. To estimate the ability of WM and WT in detecting regional dysfunction, decreased perfusion area, which was defined as < mean - 2SD by the normal profile, was used as a standard. The receiver operating characteristics (ROC) area analysis was also performed. RESULT: In the normal profile, % tracer uptake was decreased in the anterior segments of female group, no significant difference was observed between male and female in WM and WT. WM was decreased in the septum and increased in the lateral segment. WT didn't show any difference regional difference. Sensitivity and specificity of WM were 56%/91% in the anterior, 0%/100% in the septum, 43%/87% in the inferior, 31%/85% in the lateral. WT were 67%/93% in the septum, 67%/79% in the inferior, and 59%/81% in the septum. The area under ROC curve was WM 0.63, WT 0.85 (p < 0.005 between WM and WT) in the septum, in inferior WM 0.77, WT 0.80 (p = 0.57), in anterior WM 0.86, WT 0.87 (p = 0.095), in lateral WM 0.68, WT 0.78 (p = 0.037). CONCLUSION: In normal profile, the % tracer uptake in the anterior wall decreased in females, but WM and WT did not show significant difference in each region affected this influence. The septal WM was decreased in the normal profile and ability to diagnose regional function was also decreased compared with WT. Thus, we can conclude that WT is preferable for detecting septal functional abnormality.

Aged↗
PubMed1989

Variations in the delivery of medical care in central New York.

This paper presents an application of the Wennberg small area analysis methodology to the experience of a metropolitan county in upstate New York. It illustrates how these techniques can be used cooperatively by physicians and business to address purchaser concerns such as the impact of ambulatory surgery, the potential need for preadmission review and second opinion programs, and the contribution of high cost procedures to overall utilization and cost. The study found that use rates for most diagnoses and procedures were substantially below statewide norms, representing an annual savings of more than +30 million. It also found ambulatory surgery was effectively used as an alternative to hospitalization, and that high use rate areas involved high cost procedures targeted by second opinion and preadmission review programs.

Delivery of Health Care↗
PubMed2003

Spray freezing into liquid (SFL) particle engineering technology to enhance dissolution of poorly water soluble drugs: organic solvent versus organic/aqueous co-solvent systems.

A spray freezing into liquid (SFL) particle engineering technology has been developed to produce micronized powders to enhance the dissolution of poorly water soluble active pharmaceutical ingredients (APIs). Previously, a tetrahydrofuran (THF)/water co-solvent was used as the solution source in the SFL process. In the present study, an organic system was developed to further enhance the properties of particles produced by SFL. The influence of solution type (e.g. organic versus organic/water) on the physicochemical properties of SFL powders was investigated and compared. The physicochemical properties of SFL carbamazepine (CBZ)/poloxamer 407/PVP K15 (2:1:1 ratio) powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size distribution, surface area analysis, contact angle measurement, Karl-Fisher (KF) titration, gas chromatography (GC) analysis, HPLC analysis, and dissolution testing. The CBZ loading in the feed solution of the SFL acetonitrile system was 2.2% (w/w), which was greater than 0.22% (w/w) loading of the THF/water co-solvent system. XRD results indicated CBZ was amorphous in SFL powders produced by either system. SEM micrographs indicated that SFL powders from acetonitrile appeared less porous with a smaller primary particle size than particles from the co-solvent. The M50 (50% cumulative percent undersize) of micronized powder from the SFL acetonitrile system and the THF/water co-solvent system with 0.22% CBZ loading were 680nm and 7.06microm, respectively. The surface area of SFL powders from the acetonitrile and co-solvent systems were 12.89 and 13.31m(2)/g, respectively. The contact angle of the SFL powders against purified water was about 35 degrees for both systems. The SFL powders from both systems exhibited similar and significantly enhanced dissolution rates compared to the bulk CBZ. Acetonitrile was an effective alternative solvent to THF/water co-solvent for use with the SFL micronization process to produce free flowing particles containing CBZ with significantly enhanced wetting and dissolution properties.

Chemical Engineering↗
PubMed2005

Spray freezing into liquid versus spray-freeze drying: influence of atomization on protein aggregation and biological activity.

Protein aggregation and enzyme activity were compared for reconstituted lysozyme particles produced by two cryogenic technologies, spray freezing into liquid (SFL) and spray-freeze drying (SFD). The particles were characterized by enzyme activity measurements, scanning electron microscopy (SEM), light scattering, X-ray photoelectron spectroscopy (XPS) and BET specific surface area analysis. Highly porous microparticle aggregates of protein nanoparticles, observed by SEM, were produced by both processes. The smaller degree of protein aggregation and smaller losses in enzyme activity for the SFL process relative to the SFD process were due primarily to the spraying step. The higher stability of the SFL versus SFD powders was consistent with the smaller surface excess of lysozyme measured by XPS in SFL, resulting from the reduced time of exposure to the air-water interface during atomization. For pure lysozyme, the degree of aggregation and enzyme activity were comparable for lyophilization and SFL, despite the much larger particle surface area for SFL.

Enzyme Stability↗
PubMed1998

Can census offices publish statistics for more than one small area geography? An analysis of the differencing problem in statistical disclosure.

"The paper describes a problem faced by National Statistical Offices when publishing the results of decennial censuses for small geographical areas. If they publish statistical tables for two or more sets of areas, users can compare the tables and produce new statistics for the areas formed by differencing, which may have populations below confidentiality thresholds. To investigate the problem, the authors construct a software system and carry out a series of experiments using a large synthetic population base for Yorkshire and Humberside [in England]. The results indicate that publishing statistics for zones close in size to the primary areas is not safe unless the zones have been carefully designed. However, publishing statistics for sufficiently large areas such as 5km grid squares or postal sectors alongside enumeration districts is safe."

Censuses↗
PubMed1995

Tibiofemoral contact stress and stress distribution evaluation of total knee arthroplasties.

The Fuji film (Itochu, Los Angeles, CA) area analysis technique demonstrates that a more accurate assessment of tibiofemoral contact stresses is possible when the film is used at 37 degrees C and at the upper end of its sensitivity range (in this case, a 2,000-N load). An AMK with a regular and Hylamer-M insert (DePuy, Warsaw, IN), an MG II (Zimmer, Warsaw, IN), an Omnifit (Osteonics, Allendale, NJ), an Ortholoc III (Dow Corning Wright, Midland, MI), a PCA II (Howmedica, Rutherford, NJ), and a PFC (Johnson & Johnson Orthopaedics, Raynham, MA) had average contact stresses that varied only 12% at 60 degrees flexion. At 0 degrees, 15 degrees and 60 degrees flexion, stresses ranged from 13 to 25 MPa. Contact area distribution ratios, which were smaller at 37 degrees C than at 24 degrees C, provide a quantitative means of grouping implants according to the shape of the tibiofemoral contact area. The Omnifit, MG II, PCA II, and PFC had small ratios (symmetric areas). The AMK and Ortholoc III had large ratios (asymmetric contact areas). If the impression is reflective of wear, it would be expected to be focal in knees with small ratios and contact areas, and uniform in knees with large ratios and contact areas, whereas large ratios and small areas would imply a linear wear pattern. Calibrated electrical resistance contact stress measurements indicated that the Fuji film measurements underestimated the magnitude of contact stresses. They also provided a means of quantifying the rate of area increase during initial loading of the knees, with the highest area increase noted for the knee with the roughest insert (Ortholoc III) and the lowest area increase for the knee with the smoothest insert (PCA II).

Electric Impedance↗
PubMed2001

17-beta estradiol can reduce secondary ischemic damage and mortality of subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a unique disorder commonly occurring when an aneurysm ruptures, leading to bleeding and clot formation, with a higher incidence in females. To evaluate the influence of 17-beta estradiol (E2) in the outcome of subarachnoid hemorrhage, SAH was induced by endovascular puncture of the intracranial segment of internal carotid artery in 15 intact females (INT), 19 ovariectomized females (OVX), and 13 ovariectomized female rats with E2 replacement (OVX + E2). Cerebral blood flow was recorded before and after SAH. All animals were decapitated immediately after death or 24 hours after SAH for clot area analysis. Brains were sliced and stained with 2,3,5-triphenyltetrazolium chloride (TTC) for secondary ischemic lesion analysis. The cortical cerebral blood flow (CBF), which was measured by a laser-Doppler flowmeter, decreased to 29.6%+/-17.7%, 22.8%+/-8.3%, and 43.5%+/-22.9% on the ipsilateral side (P = 0.01), and decreased to 63.4%+/-14.1%, 57.4%+/-11.0%, and 66.6%+/-17.9% on the contralateral side (P = 0.26) in INT, OVX, and OVX + E2, respectively. The subcortical CBF, which were measured by the H2 clearance method, were 7.77+/-12.03, 7.80+/-8.65, and 20.58+/-8.96 mL 100 g(-1) min(-1) on the ipsilateral side (P < 0.01), and 21.53+/-2.94, 25.13+/-3.01, and 25.30+/-3.23 mL 100 g(-1) min(-1) on the contralateral side in INT, OVX, and OVX + E2, respectively. The mortality was 53.3%, 68.4%, and 15.4% in INT, OVX, and OVX + E2, respectively (P = 0.01), whereas no significant difference in clot area was noted among the groups. The secondary ischemic lesion volume was 9.3%+/-8.4%, 24.3%+/-16.3%. and 7.0%+/-6.4% in INT, OVX, and OVX + E2, respectively (P < 0.01). This study demonstrated that E2 can reduce the mortality and secondary ischemic damage in a SAH model without affecting the clot volume.

Animals↗
PubMed2007

Quantifying angiogenesis in VEGF-enhanced tissue-engineered bladder constructs by dynamic contrast-enhanced MRI using contrast agents of different molecular weights.

PURPOSE: To compare Gadomer, a macromolecular magnetic resonance (MR) contrast agent, and gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) for quantifying angiogenesis in tissue-engineered bladder constructs. MATERIALS AND METHODS: Constructs enhanced with vascular endothelial growth factor (VEGF) were grafted onto the bladder of 12 rabbits (N= 3/VEGF, VEGF = 0,10,15,20 ng/g tissue). After eight days dynamic contrast-enhanced MRI (DCE-MRI) was performed in each animal using Gadomer and Gd-DTPA, separated by a one-hour interval. DCE-MRI parameters were calculated from two-compartment pharmacokinetics (plasma volume fraction, v(p); transfer constant, K(trans)) and model-free analysis, area under the concentration-time curve (AUC). Histology assessment of microvessel density (MVD) and Evans blue permeability were compared to DCE-MRI. RESULTS: MVD was elevated (P < 0.05) at the highest VEGF but not among lower levels; permeability differences were absent. Contrast enhancement increased with VEGF and was better resolved with Gadomer than Gd-DTPA. Gadomer was the better assay for estimating plasma volume: v(p) provided the best distinction (P < 0.005), but both v(p) and AUC were correlated to MVD. With Gd-DTPA, only AUC distinguished MVD differences (P< 0.05). Changes in K(trans) were insignificant. CONCLUSION: Macromolecular contrast agents are valuable for monitoring angiogenesis in tissue-engineered bladder grafts. Compared to Gd-DTPA, Gadomer provides more accurate and precise quantification of microvessel function, and is better suited to pharmacokinetic analysis for accurate physiological quantification.

Analysis of Variance↗
PubMed2001

Toward a concept of stretch-coupling in smooth muscle. I. Anatomy of intestinal segmentation and sleeve contractions.

Motility patterns and their structural basis were studied by video analysis, light and electron microscopy on the physiologically distended gut from normal and W/W(v) suckling mice and normal adult mice. Empty or diltiazem-relaxed intestine were used as references. In contrast to conventional primary aldehyde fixation, a brief primary fixation with osmic acid before aldehydes preserved the visible contraction patterns and revealed dynamic increases in the number of peg-and-socket junctions coupling muscle cells mutually and with interstitial cells of Cajal (ICC). In tissue engaged in segmentation, the major increase was in the circular muscle and involved the ICC-DMP (integrated in the circular muscle layer at the site of the deep muscular plexus), whereas the increase during sleeve contractions was in the longitudinal muscle and involved the ICC-AP (located at the site of Auerbach's plexus). The number and distribution of gap junctions were unaffected. Area analysis of cell profiles supported the involvement of circular muscle in segmentation, but longitudinal muscle alone in sleeve contractions. The gut of both normal and W/W(v) sucklings (and adults) contracted during segmentation at frequencies close to reported slow-wave frequencies. In W/W(v) sucklings, ICC-AP were absent whereas ICC-DMP were present in adult configuration. Before Day 8 pp gap junctions were seen only between ICC-DMP. In the sucklings ICC-DMP may be responsible for rapid circumferential coordination and pacemaking of ring contractions. The geometry, organization, and dynamic regulation of peg-and-socket junctions strongly suggest a crucial role in coordination of smooth muscle and pacemakers, probably as stretch sensors, mediating a 'stretch-coupling' in the system.

Animals↗
PubMed2006

Stability of lithium hydride in argon and air.

The oxidation behaviors of LiH under a high purity argon atmosphere, an argon atmosphere with some O2 and H2O impurities, and ambient air at both room and high temperatures, are investigated using a variety of analytical instruments including X-ray diffractometry, thermogravimetry, mass spectrometry, scanning electron microscopy, and specific surface area analysis. The oxidation behaviors of the ball-milled LiH under different atmospheres are also studied and compared with those without ball milling. It is shown that no oxidation of LiH occurs under a high-purity argon atmosphere. However, oxidation of LiH takes place when the argon atmosphere contains some H2O and O2 impurities. At temperatures higher than approximately 55 degrees C, oxidation of LiH proceeds via the reaction of LiH + 1/4 O2 = 1/2 Li2O + 1/2 H2, whereas at room temperature oxidation of LiH is likely caused by the simultaneous reactions of LiH + H2O = LiOH + H2 and LiH + 1/2 O2 = LiOH. The oxidation behavior of LiH in ambient air with a 27% relative humidity can be well described by the Johnson-Mehl-Avrami equation. Furthermore, the ball-milled LiH oxidizes faster than the unmilled one, which is due to the finer particle size and larger surface area of the ball-milled powder.

Journal Article↗
PubMed2005

Immunogenic membrane-associated proteins of Mycobacterium tuberculosis revealed by proteomics.

Membrane-associated proteins of Mycobacterium tuberculosis offer a challenge, as well as an opportunity, in the quest for better therapeutic and prophylactic interventions against tuberculosis. The authors have previously reported that extraction with the detergent Triton X-114 (TX-114) is a useful step in proteomic analysis of mycobacterial cell membranes, and detergent-soluble membrane proteins of mycobacteria are potent stimulators of human T cells. In this study 1-D and 2-D gel electrophoresis-based protocols were used for the analysis of proteins in the TX-114 extract of M. tuberculosis membranes. Peptide mass mapping (using MALDI-TOF-MS, matrix assisted laser desorption/ionization time of flight mass spectrometry) of 116 samples led to the identification of 105 proteins, 9 of which were new to the M. tuberculosis proteome. Functional orthologues of 73 of these proteins were also present in Mycobacterium leprae, suggesting their relative importance. Bioinformatics predicted that as many as 73% of the proteins had a hydrophobic disposition. 1-D gel electrophoresis revealed more hydrophobic/transmembrane and basic proteins than 2-D gel electrophoresis. Identified proteins fell into the following major categories: protein synthesis, cell wall biogenesis/architecture and conserved hypotheticals/unknowns. To identify immunodominant proteins of the detergent phase (DP), 14 low-molecular-mass fractions prepared by continuous-elution gel electrophoresis were subjected to T cell activation assays using blood samples from BCG-vaccinated healthy donors from a tuberculosis endemic area. Analysis of the responses (cell proliferation and IFN-gamma production) showed that the immunodominance of certain DP fractions was most probably due to ribosomal proteins, which is consistent with both their specificity for mycobacteria and their abundance. Other membrane-associated proteins, including transmembrane proteins/lipoproteins and ESAT-6, did not appear to contribute significantly to the observed T cell responses.

Bacterial Proteins↗