On fuzzy correlations

A general framework for dealing with numerical measurements in an approximate, uncertain, or fuzzy environment is presented. A fuzzy measurement is defined. It possesses several unique properties, which arise from its physical nature and distinguish it from concepts such as the fuzzy number. These properties, which include the fuzzy correlation term and the fuzzy Equality relation, follow directly from physical considerations. The introduction of the fuzzy correlation term provides a mathematical tool for representing any correlation relations, which may exist between different fuzzy measurements. The main function of the fuzzy correlation term is to eliminate, or filter out, measurement values that are unlikely, given other fuzzy measurements. Thus, using the fuzzy correlation term, the range of possible measurement values is limited by physical realities. The information represented by the fuzzy correlation term is shown to be of great value in providing a wider picture of reality than it is possible to obtain by simply considering individual fuzzy measurements. Arithmetic operations on fuzzy measurements and functions of fuzzy measurements are also discussed, leading to the derivation of the fuzzy Riemann integral and its applications.

Phage display selection of Affibody molecules with specific binding to the extracellular domain of the epidermal growth factor receptor

Affibody molecules specific for the epidermal growth factor receptor (EGFR) have been selected by phage display technology from a combinatorial protein library based on the 58-residue, protein A-derived Z domain. EGFR is overexpressed in various malignancies and is frequently associated with poor patient prognosis, and the information provided by targeting this receptor could facilitate both patient diagnostics and treatment. Three selected Affibody variants were shown to selectively bind to the extracellular domain of EGFR (EGFR-ECD). Kinetic biosensor analysis revealed that the three monomeric Affibody molecules bound with similar affinity, ranging from 130 to 185 nM. Head-to-tail dimers of the Affibody molecules were compared for their binding to recombinant EGFR-ECD in biosensor analysis and in human epithelial cancer A431 cells. Although the dimeric Affibody variants were found to bind in a range of 25-50 nM affinities in biosensor analysis, they were found to be low nanomolar binders in the cellular assays. Competition assays using radiolabeled Affibody dimers confirmed specific EGFR-binding and demonstrated that the three Affibody molecules competed for the same epitope. Immunofluorescence microscopy demonstrated that the selected Affibody dimers were initially binding to EGFR at the cell surface of A431, and confocal microscopy analysis showed that the Affibody dimers could thereafter be internalized. The potential use of the described Affibody molecules as targeting agents for radionuclide based imaging applications in various carcinomas is discussed.

Adenovirus 5 vector genetically re-targeted by an Affibody molecule with specificity for tumor antigen HER2/neu

In order to use adenovirus (Ad) type 5 (Ad5) for cancer gene therapy, Ad needs to be de-targeted from its native receptors and re-targeted to a tumor antigen. A limiting factor for this has been to find a ligand that (i) binds a relevant target, (ii) is able to fold correctly in the reducing environment of the cytoplasm and (iii) when incorporated at an optimal position on the virion results in a virus with a low physical particle to plaque-forming units ratio to diminish the viral load to be administered to a future patient. Here, we present a solution to these problems by producing a genetically re-targeted Ad with a tandem repeat of the HER2/neu reactive Affibody molecule (ZH) in the HI-loop of a Coxsackie B virus and Ad receptor (CAR) binding ablated fiber genetically modified to contain sequences for flexible linkers between the ZH and the knob sequences. ZH is an Affibody molecule specific for the extracellular domain of human epidermal growth factor receptor 2 (HER2/neu) that is overexpressed in inter alia breast and ovarian carcinomas. The virus presented here exhibits near wild-type growth characteristics, infects cells via HER2/neu instead of CAR and represents an important step toward the development of genetically re-targeted adenoviruses with clinical relevance.

Acrylamide, an in vivo thyroid carcinogenic agent, induces DNA damage in rat thyroid cell lines and primary cultures

Chronic treatment of rats with acrylamide induces various tumors among which thyroid tumors are the most frequent. The aim of the present study was to develop an in vitro model of acrylamide action on thyroid cells to allow the investigation of the mechanism of this tumorigenic action. The first part of the study considered as targets, characteristics of thyroid metabolism, which could explain the thyroid specificity of acrylamide action: the cAMP mitogenic effect and the important H2O2 generation by thyroid cells. However, acrylamide did not modulate H2O2 or cAMP generation in the thyroid cell models studied. No effect on thyroid cell proliferation was observed in the rat thyroid cell line FRTL5. On the other hand, as shown by the comet assay, acrylamide induced DNA damage, as the positive control H2O2 in the PC Cl3 and FRTL5 rat thyroid cell lines, as well as in thyroid cell primary cultures. The absence of effect of acrylamide on H2AX histone phosphorylation suggests that this effect does not reflect the induction of DNA double strand breaks. DNA damage leads to the generation of mutations. It is proposed that such mutations could play a role in the carcinogenic effect of acrylamide. The mechanism of this effect can now be studied in this in vitro model.

Boys with high body masses have an increased risk of developing asthma: findings from the National Longitudinal Survey of Youth (NLSY)

OBJECTIVE

To determine the relation between body mass index and the development of asthma in children.

DESIGN

Prospective study of 4393 asthma-free children followed for up to 14 years.

SETTING

Children of participants in the National Longitudinal Survey of Youth.

METHODS

Analysis was limited to children who were followed from birth and were asthma-free during the first 24 months of life. The outcome was the development of asthma during follow-up (incident asthma). Body mass index (BMI) was our main predictor of interest. Survival analyses, using time to development of asthma as the main endpoint, were stratified by sex and controlled for race/ethnicity, poverty status, and prenatal maternal smoking.

RESULTS

Asthma developed in 218 (5.0 %) children during the follow-up period. The relation between BMI and incident asthma varied by sex. A BMI > or =85th percentile at age 2-3 years was a risk factor for subsequent asthma development in boys (hazard ratio (HR) 1.6 95% confidence interval (CI) 1.1, 2.4) but not girls (HR 0.8, 95% CI 0.5, 1.4). Similarly, boys with BMIs always > or =85th percentile were at increased risk for subsequent asthma development (HR 2.4, 95% CI 1.4, 4.4) but not girls (HR 1.5, 95% CI 0.7, 2.9).

CONCLUSION

Boys with high body masses may be at an increased risk for developing asthma.

In vitro assessment of antimicrobial peptides as potential agents against several oral bacteria

BACKGROUND

Antimicrobial peptides are components of the innate immunity that play an important role in systemic and oral health.

OBJECTIVES

The antibacterial activity of the amphibian-derived K4 -S4(1-15)a antimicrobial peptide was tested against oral pathogens associated with caries and periodontitis and compared with the activities of the human-derived antimicrobial peptides LL-37 and dhvar4a.

METHODS

Growth inhibition of planktonic bacteria was tested using standard microdilution assays. Live/Dead staining followed by confocal scanning laser microscopy (CSLM) was used to determine the bactericidal effect of K4 -S4(1-15)a on Streptococcus mutans attached to a glass surface or grown as biofilm.

RESULTS

The cariogenic species S. mutans, Streptococcus sobrinus, Lactobacillus paracasei and Actinomyces viscosus were resistant to LL-37 found in the oral cavity. Porphyromonas gingivalis was the species most resistant to the three tested peptides. K4 -S4(1-15)a demonstrated the highest activity against the tested planktonic bacteria. In addition, K4 -S4(1-15)a was bactericidal to surface-attached S. mutans as well as to S. mutans biofilms grown in vitro. However, surface attachment increased S. mutans resistance to the antimicrobial peptide.

CONCLUSIONS

Our results support growing evidence suggesting the use of antimicrobial peptides for prevention and treatment of oral disease.

Patterns of use of antithrombotic therapy and quality of anticoagulation among patients with non-valvular atrial fibrillation in clinical practice

We conducted a retrospective cohort study of thromboprophylaxis rates and the quality of anticoagulation control among patients with atrial fibrillation (AF) using a large, geographically diverse database of electronic medical records. The study population consisted of 13,709 AF patients treated in US outpatient physician practices. Approximately two-thirds were prescribed warfarin alone or in combination with another drug. Older patients, males, and those with congestive heart failure (CHF) or prior stroke were more likely to receive antithrombotic therapy. Among 6454 patients treated with warfarin who had at least two valid prothrombin time/international normalised ratio test results, approximately half of study days were spent in target range. Female sex, CHF and residence in the Northeast were associated with more time out of range. Our study confirms that, in routine medical practice, warfarin is not prescribed for substantial numbers of eligible patients, and anticoagulation control with warfarin is suboptimal for many of those at risk for thromboembolism.

Stimulation of unidirectional pulses in excitable systems

Using a judicious spatial shape of input current pulses (and electrodes), responses of an excitable system (FitzHugh-Nagumo) appear as unidirectional pulses (UDP's) instead of bidirectional ones (in one dimension) or circular ones (in two dimensions). The importance of the UDP's for a possible mechanism for pinpointing the reentry cycle position and for a possible use in tachycardia suppression is discussed.

Adherence to Calcium Channel Blocker Therapy in Older Adults: A Comparison of Amlodipine and Felodipine

The efficacy of dihydropyridine calcium channel blockers for treating hypertension appears to be similar, but a variety of factors, including patient characteristics, tolerability and pharmacokinetic properties, may influence treatment adherence and outcome. We aimed to evaluate treatment adherence in clinical practice among older hypertensive adults (50+ years) prescribed amlodipine or felodipine for the first time as part of the California Medicaid (Medi-Cal) program. We used a retrospective, matched, cohort-analysis design. Over 1 year, patients prescribed amlodipine were 21% less likely to discontinue study treatment than those prescribed felodipine. Discontinuation tended to occur early, with 20% and 30% of amlodipine and felodipine patients, respectively, discontinuing treatment after one prescription. A non-significant difference in favour of amlodipine was demonstrated for anti-anginal medication use among patients taking these drugs at baseline. This study suggests that use of amlodipine may be associated with improved adherence, compared with felodipine, among older out-patients in the Medi-Cal program.

Evaluation of cetylpyridinium chloride for infection control in storage solution

Storage solution is used in in vitro experimental studies to prevent dehydration of teeth collected immediately after extraction and to prevent bacterial and fungal growth in the storage media. The chemical nature of the storing agent may affect the tooth structure and material properties at the tested interface. The aim of this study was to evaluate the use of 0.1% cetylpyridinium chloride (CPC) as a new storage solution and to assess the possible effect of 0.1% thymol on microleakage and bond strength. Forty extracted human teeth were collected from 10 different dental clinics. Immediately after extraction, the teeth were randomly divided and immersed in four different storage solutions. Two test solutions of 0.1% CPC (group C) and 0.1% thymol (group T) were compared with phosphate-buffered saline (Group S - positive control) and to 3% H2O2 (group H - negative control). Bond strength test and dye penetration evaluation were then carried out. The findings suggest that the use of 0.1% CPC as storage solution does not affect bond strength to enamel. However, it may increase dye penetration at the cervical margin. The effect of 0.1% thymol on shear bond strength and dye penetration is similar to the effect of phosphate-buffered saline.

Relationship of asthma to irritant gas exposures in pulp and paper mills

The potential of chronic or acute irritant gas exposures to cause asthma or a variant condition, reactive airways dysfunction syndrome (RADS) was investigated by observing asthma incidence in a large working population, using person-years at risk (P-YR) to compute relative rates (RR). Health data came from employee examinations at 62 pulp and paper plants. The 39122 workers who denied asthma beginning before the observation period included: 19326 denying irritant exposures, with no gassing exposures; 19349 with self-reported irritant exposures, and no gassing; and 447 with documented gassings. Asthma was defined as self-reported asthma beginning after the start of observation. P-YR accrued from September 29, 1986, for the nonexposed and exposed workers, and from date of first gassing for gassed workers, and ended with disease onset in any who developed asthma. RR of asthma with 95% confidence intervals (CI95) were calculated for the exposed and gassed groups, relative to the nonexposed. Exposed (nongassed) workers had an elevated asthma rate, RR=1.48, CI95=1.17-1.86, after adjustment for effects of gender and number of examinations. The rate in gassed workers was not significantly elevated: RR=1.95, CI95=0.75-5.08. Of the five asthma cases occurring after gassings, none conformed to diagnostic criteria for RADS. Chronic exposures were associated with increased rate of asthma onset, which must be interpreted with caution because self-reported data defined both exposure category and disease. Documented gassings were not associated with significantly increased rate, and none of 447 gassed persons developed RADS.

Formulation, development and characterization of sustained release varnishes containing amine and stannous fluorides

This study describes properties of potential sustained release varnishes (SRV) containing amine fluoride or amine fluoride with stannous fluoride. The release kinetics, antibacterial properties and antiadhesion properties of two potential varnishes were tested. The varnish of ethylcellulose matrix was found to release fluoride for 4 h in vitro, while the formulation based on hydroxypropylmethylcellulose acetate succinate had a rapid release rate. Hydroxyapatite tablets coated with ethylcellulose-based SRV increased adhesion of Streptococcus mutans, while tablets coated with hydroxypropylmethylcellulose acetate succinate-based SRV decreased bacterial adhesion. Both types of SRV demonstrated a strong antibacterial effect on bacteria in biofilm.

A computer-assisted anatomical study of the nasofrontal region

OBJECTIVES/HYPOTHESIS

Objectives were as follows: 1) to define the variations of the uncinate process' superior attachment, 2) to study the diameter of the frontal sinus ostium, 3) to study the prevalence of the agger nasi cells, and 4) to evaluate the side-to-side variability of these structures.

STUDY DESIGN

A retrospective clinical study at a tertiary care center.

METHODS

One hundred forty-four consecutive computed tomography scans were studied with image-guided surgery software (InstaTrak, Visualization Technology, Inc., Wilmington, MA) that provides continuous coronal, sagittal, and axial sections. We reported the superior attachment sites of the uncinate process, the diameter of the frontal sinus ostium, and prevalence of the agger nasi cells.

RESULTS

The uncinate process' main superior attachment into the surrounding structures was found to have the following distribution: 52% to the lamina papyracea, 18.5% to the posteromedial wall of the agger nasi cell, 17.5% to the lamina papyracea and the junction of the middle turbinate with the cribriform plate, 7% to the junction of the middle turbinate with the cribriform plate, 3.6% to the ethmoid roof, and 1.4% to the middle turbinate. The frontal ostium anterior-posterior diameter (mean +/- SD) was 7.22 +/- 2.78 mm and its transverse diameter (mean +/- SD) was 8.92 +/- 2.95 mm. Agger nasi cells were found in 78% of the scans.

CONCLUSIONS

The frontal sinus opens into the middle meatus medial to the uncinate process in 88% of the patients and lateral to the uncinate process in 12% of the patients. The naturally wide dimensions of the frontal ostium help to explain why postoperative patency can be achieved merely by exposing the ostium without the need to enlarge it. The frontal ostium dimensions in one side may differ considerably from the contralateral side. An agger nasi cell or a terminal recess, or both, are found in most cases. Image-guided surgery software is a helpful new tool for anatomical studies and for preoperative evaluation.

Antibacterial effect of parabens against planktonic and biofilm Streptococcus sobrinus

Tooth decay is an infectious disease caused by bacteria immobilized on the tooth surfaces. Eradication of these bacteria, for example Streptococcus sobrinus (S. sobrinus), from the oral cavity is essential in the prevention and treatment of tooth decay. We have tested the antimicrobial effect of several paraben derivatives such as methyl (MP), ethyl (EP), propyl (PP) and butyl (BP) against immobilized and planktonic S. sobrinus. The antibacterial effect was as follows: MP>EP>PP=BP on immobilized bacteria and MP>EP=PP>BP on planktonic bacteria. An antibacterial synergistic effect was found between several combinations of parabens on immobilized and planktonic S. sobrinus. Our results indicate that parabens are potential antibacterial agents against immobilized or planktonic bacteria found in the oral cavity.