Optimization of a fluorescence sandwich enzyme-linked immunosorbent assay for detection of Escherichia coli O157:H7 in apple juice.

Sandwich enzyme-linked immunosorbent assay, especially when coupled with biosensor technology, is a simple methodology that can rapidly screen juices for Escherichia coli O157:H7 contamination. However, sampling directly from apple juice and ciders has been postulated to reduce immunoassay sensitivity. In fluorescence sandwich enzyme-linked immunosorbent assays using commercially available polyclonal or monoclonal antibodies, sampling pasteurized apple juice spiked with E. coli O157:H7 compared to spiked phosphate-buffered saline shifted the range of detection. The spiked apple juice range of detection was 10(4) to 10(6) CFU/ml, whereas that for spiked phosphate-buffered saline was 10(6) to 10(8) CFU/ml, representing a hundredfold difference in sensitivity. Apple juice also increased background fluorescence intensity (P < 0.001) while reducing the net fluorescence intensity per CFU (P < 0.001). The addition of the polymer polyvinylpyrrolidone to apple juice significantly improved assay performance by increasing sensitivity and net fluorescence intensity per CFU and by reducing background fluorescence. Adjusting pH of apple juice from 3.9 to 7.4 improved assay performance but not to the degree seen with phosphate-buffered saline or polyvinylpyrrolidone-treated apple juice samples. The apple juice polyphenol, epicatechin, reduced net fluorescence intensity in a concentration-dependent manner, a change that was reversed by polyvinylpyrrolidone. Taken all together, these results suggest that polyvinylpyrrolidone can improve detection of O157:H7 in juices by reducing the effect of polyphenols on fluorescence sandwich enzyme-linked immunosorbent assay performance.

Anatomical characteristics of the upper serratus anterior: cadaver dissection.

STUDY DESIGN: A descriptive study of the anatomical characteristics of the upper serratus anterior. OBJECTIVES: To delineate the upper serratus anterior with comparison to classical descriptions of the anatomy of the muscle as a whole. BACKGROUND: Although the serratus anterior has a major role in scapulothoracic stability, description of the separate function and anatomy of the upper, middle, and lower portions of the muscle has been limited. METHODS AND MEASURES: Bilateral anatomical dissection of 8 cadavers (3 female and 5 male) exposed 13 serratus anterior and surrounding structures for review. The number of serrations, attachment sites, length, and girth of the upper serratus anterior were measured. RESULTS: The upper serratus anterior presented with dual serrations and single serrations in 7 (54%) and 6 (46%) of 13 observations, respectively. Attachments to both first and second ribs were noted in 6 (46%) of the 13 observations. The remaining proximal attachments were to the second rib only, the first rib only, and dual attachments to the second and third ribs. In all cases, cranial attachments were to the superior scapular angle blending with the levator scapulae attachment. Length ranged from 4.8 to 9.0 cm (mean +/- SD, 6.9 +/- 1.2 cm). The girth ranged from 3.0 to 8.5 cm (mean +/- SD, 6.1 +/- 1.5 cm). One or more branches of the long thoracic nerve were observed to consistently innervate the upper serratus anterior fibers. CONCLUSION: The upper serratus anterior demonstrated wide variation in anatomy and was noted to be distinct in appearance and peripheral innervation from the middle and lower serratus anterior.

Upper-extremity exercise training in heart failure.

PURPOSE: Aerobic exercise training (ExTR), predominantly performed with lower extremities, has been used to reverse heart failure (HF)-related exercise intolerance. The present study determined the safety and efficacy of upper-extremity exercise in HF subjects because daily activities are performed using both upper and lower extremities and there is little cross-training effects between extremities. METHODS: Seven subjects underwent 36 sessions (40 minutes, 3 times per week for 12 weeks) of upper-extremity ExTR (ARM ExTR) using arm ergometers, the arm function of a NuStep device, and an Airdyne stationary cycle. Exercise intensity and duration during weeks 1 to 4 were gradually increased to achieve a 75% to 85% peak heart rate. Pre- and post-ExTR tests included arm ergometer cardiopulmonary testing with echocardiography and quality of life self-administered surveys. RESULTS: After ARM ExTR test duration increased by 22% (P = .008), respiratory exchange ratio increased by 10% (P = .02), whereas peak oxygen consumption was not improved. Echocardiographic parameters were not altered by ARM ExTR. The total scores of both the Minnesota Living With Heart Failure Questionnaire (P = .02) and the Medical Outcomes Study-36 questionnaire (P = .05) were improved, but the Functional Status Questionnaire scores were not improved. CONCLUSIONS: Although this study was limited in the number of subjects and lacked a control group, results indicate that ARM ExTR is safe and well-tolerated by persons diagnosed with HF, a finding that is relevant for individuals with HF who cannot exercise with lower extremities.

Effects of chlorine injury, starvation, and Colitag(TM) enrichment on sandwich enzyme-linked immunosorbent assay (sELISA) detection of Escherichia coli O157:H7.

The validity of ELISA for detection of E. coli O157:H7 under many conditions is not proven. In this work, sELISA was able to detect bacteria after sub-lethal chlorine exposure and after seven days of starvation with little to no change in limit of detection and fluorescence signal as long as chlorine was not present in the sample or was neutralized by sodium thiosulfate. After Colitag enrichment, sELISA detected approximately 3 colony forming units/ml of originally added E. coli O157:H7. Thus, the present sELISA is valid for detection of E. coli O157:H7 in water sources, although sample matrices may interfere with assay.

Antibody-based detection of acid-shocked, acid-adapted, and apple juice-incubated Escherichia coli O157:H7.

Sandwich enzyme-linked immunosorbent assays (sELISA) allow for rapid detection of Escherichia coli (E. coli) O157:H7. Acidic conditions similar to those in certain foods and juices may reduce the ability to detect E. coli O157:H7. Growth of E. coli O157:H7 at pH 4 compared to pH 5-7 reduced fluorescent signal at the lower bacterial concentrations without altering the range of detection. Both acid-adaptation and a subsequent pH 7 incubation reversed sensitivity. Incubation in apple juice was not deleterious to sELISA detection. Exposure to acidic conditions can cause a small reduction in sELISA sensitivity used to detect E. coli O157:H7.