Impact of positive end-expiratory pressure during heterogeneous lung injury: insights from computed tomographic image functional modeling.

Image Functional Modeling (IFM) synthesizes three dimensional airway networks with imaging and mechanics data to relate structure to function. The goal of this study was to advance IFM to establish a method of exploring how heterogeneous alveolar flooding and collapse during lung injury would impact regional respiratory mechanics and flow distributions within the lung at distinct positive end-expiratory pressure (PEEP) levels. We estimated regional respiratory system elastance from computed tomography (CT) scans taken in 5 saline-lavaged sheep at PEEP levels from 7.5 to 20 cmH(2)O. These data were anatomically mapped into a computational sheep lung model, which was used to predict the corresponding impact of PEEP on dynamic flow distribution. Under pre-injury conditions and during lung injury, respiratory system elastance was determined to be spatially heterogeneous and the values were distributed with a hyperbolic distribution in the range of measured values. Increases in PEEP appear to modulate the heterogeneity of the flow distribution throughout the injured lung. Moderate increases in PEEP decreased the heterogeneity of elastance and predicted flow distribution, although heterogeneity began to increase for PEEP levels above 12.5-15 cmH(2)O. By combining regional respiratory system elastance estimated from CT with our computational lung model, we can potentially predict the dynamic distribution of the tidal volume during mechanical ventilation and thus identify specific areas of the lung at risk of being overdistended.

Determinants of healthcare-seeking behaviour among subjects with irritable bowel syndrome.

BACKGROUND: Doctor visits for irritable bowel syndrome are associated with high medical costs. Predictors of medical consultation for irritable bowel syndrome remain poorly understood. AIM: To determine factors associated with healthcare seeking for irritable bowel syndrome. METHODS: Subjects from previous US population-based survey were contacted 2 years later. Those who continued to have irritable bowel syndrome were included. RESULTS: 49% of subjects sought medical care for abdominal symptoms in the past year. Healthcare seeking did not differ significantly between males and females, but more females received an irritable bowel syndrome diagnosis. Predictors of irritable bowel syndrome healthcare seeking differed by gender. In multivariate analysis, age > or = 55 years (OR = 2.8, 95% CI: 1.5-5.4), fear abdominal symptoms relates to serious illness (OR = 1.7, 95% CI: 0.95-3.1), decreased bowel movements (OR = 1.8, 95% CI: 0.98-3.2), dyspepsia (OR = 1.7, 95% CI: 0.94-3.2) and pelvic pain (OR = 2.3, 95% CI: 1.2-4.4) were associated with seeking care in females. Among males, being disabled (OR = 11.6, 95% CI: 2.4-56.1) and abdominal cramping (OR =4.3, 95% CI: 1.2-15.4) were associated with seeking care. Healthcare seekers had lower irritable bowel syndrome-related quality of life. Neither pain severity nor mental health status was associated with seeking care. CONCLUSION: Healthcare-seeking behaviour among irritable bowel syndrome patients was determined by presence of comorbidities and extent that irritable bowel syndrome affected quality of life, not physical symptoms or mental health status.

Stability of irritable bowel syndrome using a Rome II-based classification.

BACKGROUND: As there is no biological marker for irritable bowel syndrome, a diagnosis is made using symptom-based criteria. AIM: To evaluate the stability of self-reported symptoms consistent with Rome II-based irritable bowel syndrome classification. METHODS: Irritable bowel syndrome subjects identified in a 2001 population-based study by modified Rome II criteria were re-contacted 2 years later. Data were collected via a web-based questionnaire. RESULTS: Of the 697 subjects, 30% remained in the same irritable bowel syndrome subtype in both surveys, 18.4% changed irritable bowel syndrome subtype and 52% no longer met the irritable bowel syndrome criteria at follow-up. Subjects continuing to meet the irritable bowel syndrome criteria were more likely to have been initially classified in the alternating irritable bowel syndrome subtype and had more psychological impairment and lower irritable bowel syndrome-related quality of life than subjects not fulfilling the irritable bowel syndrome criteria at follow-up. Lack of pain caused more subjects to fall out of the irritable bowel syndrome criteria than the absence of non-painful bowel symptoms. However, the majority of subjects that did not fulfill the pain component of the irritable bowel syndrome criteria continued to report abdominal pain of at least moderate severity. CONCLUSION: In a US population-based follow-up study using modified Rome II criteria, we found irritable bowel syndrome is episodic in nature and current classification is limited in capturing fluctuation of disease over time.

Serum immunoglobulin G (IgG) and IgG subclass responses to the RgpA-Kgp proteinase-adhesin complex of Porphyromonas gingivalis in adult periodontitis.

Serum immunoglobulin G (IgG), IgM, and IgG subclass responses to the RgpA-Kgp proteinase-adhesin complex of Porphyromonas gingivalis were examined by enzyme-linked immunosorbent assay using adult periodontitis patients and age- and sex-matched controls. Twenty-five sera from subjects with adult periodontitis (diseased group) and 25 sera from healthy subjects (control group) were used for the study. Sera and subgingival plaque samples from 10 sites were collected from each patient at the time of clinical examination. The level of P. gingivalis in the plaque samples was determined using a DNA probe. Highly significant positive associations between the percentage of sites positive for P. gingivalis and measures of disease severity (mean pocket depth, mean attachment loss, and percentage of sites that bled on probing) were found. The diseased group had significantly higher specific IgG responses to the RgpA-Kgp complex than did the control group, and the responses were significantly associated with mean probing depths and percentage of sites positive for P. gingivalis. Analysis of the IgG subclass responses to the RgpA-Kgp complex revealed that the subclass distribution for both the diseased and control groups was IgG4 > IgG2 > IgG3 = IgG1. The IgG2 response to the complex was positively correlated with mean probing depth, whereas the IgG4 response was negatively correlated with this measure of disease severity. Immunoblot analysis of the RgpA-Kgp complex showed that sera from healthy subjects and those with low levels of disease, with high IgG4 and low IgG2 responses, reacted with the RgpA27, Kgp39, and RgpA44 adhesins; however, sera from diseased subjects with low IgG4 and high IgG2 responses reacted only with the RgpA44 and/or Kgp44 adhesins. Epitope mapping of the RgpA27 adhesin localized a major epitope recognized by IgG4 antibodies in sera from subjects with high IgG4 and low IgG2 responses to the RgpA-Kgp complex which was not recognized by sera from diseased subjects with low IgG4 and high IgG2 responses.

Epitope analysis of the multiphosphorylated peptide alpha s1-casein (59-79).

The multiphosphorylated tryptic peptide alpha(s1)-casein(59-79) has been shown to be antigenic with anti-casein antibodies. In an approach to determine the amino acyl residues critical for antibody binding we undertook an epitope analysis of the peptide using overlapping synthetic peptides. With alpha(s1)-casein(59-79) as the adsorbed antigen in a competitive ELISA only two of five overlapping synthetic peptides at 1 mM significantly inhibited binding of the anti-casein antibodies. Peptides Glu-Ser(P)-Ile-Ser(P)-Ser(P)-Ser(P)-Glu-Glu and Ile-Val-Pro-Asn-Ser(P)-Val-Glu-Glu inhibited antibody binding by 20.0+/-3.6% and 60.3+/-7.9%, respectively. The epitope of Glu63-Ser(P)-Ile-Ser(P)-Ser(P)-Ser(P)-Glu-Glu70 was further localised to the phosphoseryl cluster as the peptide Ser(P)-Ser(P)-Ser(P) significantly inhibited binding of the anti-casein antibodies to alpha(s1)-casein(59-79) by 29.5+/-7.4%. Substitution of Ser(P)75 with Ser75 in the second inhibitory peptide Ile-Val-Pro-Asn-Ser(P)75-Val-Glu-Glu also abolished inhibition of antibody binding to x(s1)-casein (59-79) demonstrating that Ser(P)75 is also a critical residue for recognition by the antibodies. These data show that the phosphorylated residues in the cluster sequence -Ser(P)66-Ser(P)-Ser(P)68 and in the sequence -Pro73-Asn-Ser(P)-Val-Glu77- are critical for antibody binding to x(s1)-casein(59-79) and further demonstrate that a highly phosphorylated segment of a protein can be antigenic.

An ELISA for a multiphosphorylated peptide, alpha(s1)-casein(59-79).

Multiphosphorylated segments of proteins are predicted to be in or near epitopes. However, due to the very hydrophilic nature of multiphosphorylated peptides, epitope mapping by ELISA using conventional microtitre plates can produce false negatives due to poor antigen adsorption. We have developed a sensitive ELISA for a multiphosphorylated peptide alpha(s1)-casein(59-79) containing five phosphoseryl residues using Nunc-Immuno Maxisorp modules for antigen adsorption. The peptide alpha(s1)-casein(59-79) was detected in the ELISA at antigen coating concentrations of 1.0 microg/ml and above, using rabbit anti-casein antibodies at a dilution of 1/10,000 in Tris-buffered saline containing 0.05% (w/v) Tween 20 and 1.0% (v/v) normal goat serum. At an antigen coating concentration of 10 microg/ml, anti-casein antibodies bound to alpha(s1)-casein(59-79) and produced an absorbance of more than 100 times background. Using conventional polyvinyl chloride and polystyrene plates the peptide alpha(s1)-casein(59-79) could only be detected at very high antigen coating concentrations of 1-10 mg/ml. The addition of 0.05% (w/v) Tween 20 to the blocking, antibody diluting and wash buffers of the ELISA was shown to significantly reduce nonspecific binding of the primary antibody. Further, the inclusion of normal goat serum in the blocking and antibody diluting buffers resulted in a small but significant increase in absorbance. The ELISA developed in this study has been used successfully with a range of enzymatically derived and synthetic peptides containing one to five phosphorylated residues such that it should have general applicability to the study of antigenicity of multiphosphorylated peptides.

Anticariogenicity of calcium phosphate complexes of tryptic casein phosphopeptides in the rat.

Casein phosphopeptides (CPP) stabilize calcium phosphate through the formation of casein-phosphopeptide amorphous calcium-phosphate complexes (CPP-CP). The ability of CPP-CP to reduce caries activity was investigated by use of specific-pathogen-free rats inoculated with Streptococcus sobrinus. The animals consumed a defined cariogenic diet free of dairy products. Solutions (100 microL) of the CPP-CP (0.1, 0.2, 0.5, 1.0% w/v) were applied to the animals' molar teeth twice daily. Other groups of animals received solutions containing 500 ppm F, the non-phosphorylated peptides of a casein tryptic digest (0.5% w/v), or the calcium-phosphate complex of a synthetic octapeptide, Ac-Glu-Ser(P)-Ile-Ser(P)-Ser(P)-Ser(P)-Glu-Glu-NHMe, corresponding to the common sequence in the CPP. The CPP-CP significantly reduced caries activity in a dose-response fashion, with 1.0% CPP-CP producing 55% and 46% reductions in smooth surface and fissure caries activity, respectively, being similar to that of 500 ppm F. The anticariogenic effects of CPP-CP and fluoride were additive, since animals receiving 0.5% CPP-CP plus 500 ppm F had significantly lower caries activity than those animals receiving either CPP-CP or fluoride alone. The tryptic digest of casein with the phosphopeptides selectively removed showed no anticariogenic activity. The synthetic octapeptide-calcium phosphate complex significantly reduced caries activity, confirming that this calcium-phosphate-stabilizing portion of the casein phospho-peptides is associated with anticariogenicity. The CPP-CP did not significantly affect the level of S. sobrinus in fissure plaque.(ABSTRACT TRUNCATED AT 250 WORDS)

The significance of lymph node involvement in patients with medullary carcinoma of the breast.

Sixty-two patients with medullary carcinoma of the breast were studied. Mean survival time was 105 months. When identical stages are compared, the five and ten year survival rates for patients with medullary carcinoma of the breast parallel those for patients with infiltrating ductal carcinoma. Age, duration of symptoms, site of the primary lesion, size of the primary lesion, menopausal status and postoperative radiotherapy and the number of positive axillary lymph nodes were all evaluated for independent effects upon survival. The number of involved axillary nodes appeared to be the only worthwhile prognostic indicator. We believe that patients with medullary carcinoma of the breast and positive axillary lymph nodes should receive adjuvant chemotherapy.