Mammographic measurements before and after augmentation mammaplasty

Thirty-five augmented women underwent mammography using both the standard implant-compression technique and, when possible, the implant-displacement technique; all had preaugmentation film-screen mammography available for evaluation. The area of mammographically visualized breast tissue before and after augmentation mammaplasty was measured using a transparent grid. Patients with subglandular implants had a mean decrease of 49 percent of measurable tissue area with compression mammography and a 39 percent decrease with displacement mammography. Patients with submuscular implants had a 28 percent decrease in measurable tissue area with compression mammography and a 9 percent decrease with displacement mammography. Anterior breast tissue was seen better with displacement mammography; posterior breast tissue, with compression mammography. Most patients had some degree of parenchymal scarring and lower image quality after augmentation. State-of-the-art mammography was not possible in most patients augmented with silicone-gel-filled implants.     

Use of immunoperoxidase for the rapid identification of human myxoviruses and paramyxoviruses in tissue culture

The immunoperoxidase method, using commercially available antisera, was compared with standard virological methods for the identification and typing of 77 isolates of human myxoviruses and paramyxoviruses. Results of typing using neutralization tests and the immunoperoxidase technique were identical for 76 of the 77 isolates. With the immunoperoxidase method there was one false negative reaction, but no false positive reactions. Cross-reactivity between influenza A (soluble) and A₂/HK antisera with influenza A isolates was noted, but did not interfere with the interpretation of results. It is concluded that the immunoperoxidase method is ideally suited for the rapid identification and typing of common human respiratory viruses on a routine basis. It offers a number of decided advantages over both immunofluorescence and standard virological methods.     

Assessment of non-mydriatic fundus photography in detection of diabetic retinopathy.

Non-mydriatic retinal photography with later interpretation of the photographs was assessed as a screening method for the detection of diabetic retinopathy; when compared with an ophthalmologist''s clinical assessment in a random group of 62 diabetic patients it was accurate (false negative 6.8%, false positive 2%) and sensitive (sensitivity 96%, specificity 98%). The assessment of further management required based on analysis of the photographs was 96.5% in agreement with the further management suggested by the ophthalmologist after direct clinical assessment of the patient. If this technique were used to screen patients in a typical diabetic clinic the predicted positive accuracy rate would be 84% and the predicted negative accuracy rate 99.5%.     

A new method for the screening of solid-phase combinatorial libraries for affinity chromatography

A new methodology for the rapid assessment of affinity ligands synthesized by combinatorial solid-phase chemistry is reported. This screening strategy utilizes the target protein conjugated to FITC, and represents an almost universal technique for the preliminary screening of solid-phase combinatorial libraries. The assessment of a triazine-scaffolded solid-phase combinatorial library of ligands, designed to bind to human IgG, was performed with FITC-human IgG, and the results compared with those obtained by conventional affinity chromatographic screening assays. The effect of different molar conjugation ratios of FITC-IgG (F/P) was evaluated. Independently of the F/P ratio, no false negative results were observed, although lower F/P ratios diminished non-specific interactions and the number of false positives. The nature of the substituents on the triazine scaffold was not related to the number of false positive IgG-binding ligands. The reproducibility of the FITC technique, using FITC-human IgG conjugates with low F/P ratio (F/P=2), was also evaluated. The FITC-based technique proved to be efficient and accurate in the identification of strongly binding ligands (binding >50% of loaded protein, by standard affinity chromatographic assays), and is envisaged as a versatile and cost-effective method to screen other systems, and evaluate several binding/elution conditions at small-scale, prior to scale-up to standard affinity chromatography.     

Periumbilical rectus abdominis perforator preservation significantly reduces superficial wound complications in "separation of parts" hernia repairs

Midline ventral hernia repair with bilateral sliding myofascial rectus abdominis flaps, or the "separation of parts" technique, has low hernia recurrence rates. However, this technique, as originally described, creates massively undermined skin and subcutaneous tissue flaps. These undermined skin flaps can suffer marginal skin loss, fat necrosis, and delayed wound healing. The authors propose that preserving the periumbilical rectus abdominis perforators to the abdominal skin flaps will decrease the prevalence of postoperative superficial wound complications. A retrospective review of 66 consecutive, large, midline hernia repairs using a separation of parts technique was undertaken to identify any correlation between the preservation of periumbilical rectus abdominis perforators to the skin flaps and the prevalence of postoperative wound complications. In 25 cases, the standard separation of parts technique was performed with wide undermining of the skin and subcutaneous tissues. In 41 cases, the modified separation of parts technique was performed with maintenance of the periumbilical rectus abdominis perforators to the abdominal skin flaps.Comparison of these two groups revealed no difference in age; sex; body mass index; initial hernia size on physical examination; prevalence of smoking, diabetes, or steroid use; or prevalence of a simultaneous intraabdominal procedure. A statistically significant difference was noted in postoperative wound complications between the two groups (p < 0.05). Of patients who underwent the standard separation of parts technique, five of 25 patients (20 percent) had wound complications as compared with one of 41 patients (2 percent) who underwent the modified separation of parts technique with perforator preservation. The postoperative hernia recurrence (7 percent and 8 percent, respectively) and hematoma (4 percent and 2 percent, respectively) rates were similar in both groups. A trend of increased wound complications was noted when separation of parts was combined with an intraabdominal procedure (18 percent versus 3 percent, p = 0.08). Interestingly, within this group, the modified separation of parts technique with preservation of the periumbilical rectus abdominis perforators demonstrated a trend of fewer wound complications as compared with the standard separation of parts technique (7 percent versus 31 percent, p = 0.15). The authors conclude that preservation of the periumbilical rectus abdominis perforators significantly reduces the prevalence of major postoperative superficial wound complications in separation of parts hernia repairs. Simultaneous intraabdominal procedures with separation of parts hernia repairs seem to increase the prevalence of wound complications. This increased prevalence of wound complications seems to be minimized when the modified separation of parts technique is performed.     

Effect of Iron on Conversion of Acetic Acid to Methane During Methanogenic Fermentations

A semi-automatic method for the detection of salmonellas in food products is described. This method involves measurement of the fluorescence intensity of preparations stained with fluorescent antibody. An overall agreement of 89·6% was obtained when the method was compared with a standard cultural technique for the detection of salmonellas in foods, feeds and environmental samples, although false negatives were a problem with raw meat products. A saving in time of at least 18 h was achieved.     

Improved salvage of complicated microvascular transplants monitored with quantitative fluorometry.

Quantitative fluorometry has been used to monitor circulation in transplanted toes and cutaneous flaps in our unit since 1982. Analysis of 177 uncomplicated transplants monitored by quantitative fluorometry shows that this technique has low false indication rates for arterial occlusion (0.6 percent of patients) and venous occlusion (6.2 percent of patients). None of these patients was reexplored because of a false monitor reading, and except for single abnormal sequences, monitoring appropriately indicated intact circulation throughout the postoperative period. Quantitative fluorometry has correctly indicated vascular complications in 21 (91.3 percent) of 23 transplants over an 8-year period. The salvage rate (85.7 percent) of the fluorescein-monitored reexplored transplants was significantly higher than the salvage rates of similar reexplored transplants not monitored with fluorescein and of reexplored muscle flaps (which cannot be monitored with the fluorometer used at this unit). These clinical data indicate that quantitative fluorometry is a valid and useful postoperative monitor for transplanted toes and cutaneous flaps.     

Comparison of methods to detect biosurfactant production by diverse microorganisms

Three methods to detect biosurfactant production, drop collapse, oil spreading, and blood agar lysis, were compared for their ease of use and reliability in relation to the ability of the cultures to reduce surface tension. The three methods were used to test for biosurfactant production in 205 environmental strains with different phylogenetic affiliations. Surface tension of select strains that gave conflicting results with the above three methods was also measured. Sixteen percent of the strains that lysed blood agar tested negative for biosurfactant production with the other two methods and had little reduction in surface tension (values above 60 mN/m). Thirty eight percent of the strains that did not lyse blood agar tested positive for biosurfactant production with the other two methods and had surface tension values as low as 35 mN/m. There was a very strong, negative, linear correlation between the diameter of clear zone obtained with the oil spreading technique and surface tension (rs = -0.959) and a weaker negative correlation between drop collapse method and surface tension (rs = -0.82), suggesting that the oil spreading technique better predicted biosurfactant production than the drop collapse method. The use of the drop collapse method as a primary method to detect biosurfactant producers, followed by the determination of the biosurfactant concentration using the oil spreading technique, constitutes a quick and easy protocol to screen and quantify biosurfactant production. The large number of false negatives and positives obtained with the blood agar lysis method and its poor correlation to surface tension (rs = -0.15) demonstrated that it is not a reliable method to detect biosurfactant production.     

Immunofluorescence Identification of Thermopolyspora polyspora,the Causative Agent of Farmer's Lung

Farmer''s lung is a serious disabling pulmonary disease found in agricultural workers. The disease is believed to be a hypersensitivity to the thermophilic actinomycetes, principally Thermopolyspora polyspora. This organism is difficult to stain with the usual bacteriological stains and thus far has not been demonstrated in the lung tissue by microscopic methods. In this paper, it is demonstrated that the fluorescent-antibody technique is a simple method for the positive identification of T. polyspora. The technique can also be used as a rapid screening test for the detection of antibodies to T. polyspora in the patient''s serum. In addition, it opens up the possibility of the identification of T. polyspora in the lung tissue of patients with farmer''s lung and makes available a means for the study of the immunological reaction in the lung parenchyma. No false positive or cross-reactions with Thermoactinomyces vulgaris or Streptomyces griseus could be demonstrated.     

Modelling population growth in stage-grouped organisms: a simple extension to the Leslie model

A simple method for decomposing a population's stage grouping into the underlying age structure is described. The population's dynamics can then be predicted using standard age-structured models, such as Leslie's matrix model. The method overcomes objections to previous attempts to use Leslie's procedure for modelling population growth in stage-grouped organisms. A hypothetical example is used to illustrate the new technique.     

Lymphangiography: Its Practical Value in Surgically Staged Patients with Hodgkin's Disease

Since the introduction of “staging laparotomy” (to determine the disease''s stage) in assessing Hodgkin''s disease, some observers have argued that lymphangiography could be safely omitted in the initial diagnostic evaluation.To test these opinions a series of 75 patients with Hodgkin''s disease who had a staging laparotomy and histological correlation with lymphangiograms was reviewed. Of 16 examinations with positive results, one proved to be a false positive. Of the 14 examinations with equivocal results, one proved histologically positive. In the remaining 45 lymphangiograms, five were falsely negative. In all five of these patients abdominal lymph nodes were involved, but in areas that do not routinely opacify on lower extremity lymphangiography. The overall accuracy was 90 percent.Therapeutically, the lymphangiogram permits accurate planning for treatment by radiation therapy so that all known disease is treated and yet bone marrow is not excessively irradiated. Changes in lymph node architecture after therapy provide valuable information as to regression of the disease or signs of its early recurrence.     

A new method to assess the influence of odor on food selection in dogs

Previous research provides evidence that odor is a key driver in food selection in dogs. Dogs' flavor preferences are generally assessed through paired comparison tests based on food intake. Methods for evaluating odor preference in canines are lacking. In this study, the paired comparison test was modified by replacing standard bowls with false‐bottom bowls (FBBs). Made of two compartments separated by a drilled, stainless‐steel plate, FBBs enable odorant compounds to be placed under the food that is presented to the dogs. Several paired comparison trials were conducted on a trained canine panel with FBBs containing various odorant substances under the kibbles. Results showed that dogs were able to perceive the hidden substances and to distinguish between the bowls accordingly. These results demonstrate that the false‐bottom bowl paired comparison method could be helpful in evaluating the role of odor in dogs' food preferences, thus, also as a way of assessing food odor performance.

Practical applications

The false‐bottom bowl method is an adaptation of the paired comparison test that enables the influence of odor on dog behavior to be isolated from that stimulated by vision, taste or textural parameters. The odor impact of a hidden substance is tested under pet meal conditions. This new method could be useful in pet food industry to measure the odor potential of a new ingredient, or to understand the key food selection drivers for dogs and cats. In addition, as the olfactory stimulus is not eaten by the animal, the influence of odor in non‐food products for dogs, such as pet care and pet medicines, could also be evaluated using this method.     

Regularized ROC method for disease classification and biomarker selection with microarray data

MOTIVATION: An important application of microarrays is to discover genomic biomarkers, among tens of thousands of genes assayed, for disease classification. Thus there is a need for developing statistical methods that can efficiently use such high-throughput genomic data, select biomarkers with discriminant power and construct classification rules. The ROC (receiver operator characteristic) technique has been widely used in disease classification with low-dimensional biomarkers because (1) it does not assume a parametric form of the class probability as required for example in the logistic regression method; (2) it accommodates case-control designs and (3) it allows treating false positives and false negatives differently. However, due to computational difficulties, the ROC-based classification has not been used with microarray data. Moreover, the standard ROC technique does not incorporate built-in biomarker selection. RESULTS: We propose a novel method for biomarker selection and classification using the ROC technique for microarray data. The proposed method uses a sigmoid approximation to the area under the ROC curve as the objective function for classification and the threshold gradient descent regularization method for estimation and biomarker selection. Tuning parameter selection based on the V-fold cross validation and predictive performance evaluation are also investigated. The proposed approach is demonstrated with a simulation study, the Colon data and the Estrogen data. The proposed approach yields parsimonious models with excellent classification performance.     

A Comparison of the Fluorescent Antibody Method and a Standardized Cultural Method for the Detection of Salmonellas

The results of routine use of the indirect fluorescent antibody (FA) technique using the Spicer-Edwards H antisera set are reported for a range of agricultural and food samples. The FA technique was used on samples after the pre-enrichment incubation period in the proposed ISO method for isolation of salmonellas. The numbers of FA false positive samples ( ca. 5% overall) and FA false negative samples ( ca. 1·3%) were low, but some originally FA false positive results were later shown to be false negative cultural results.     

Determination of phosphinothricin acetyltransferase in genetically transformed canola seed by a two-antibody sandwich enzyme immunoassay

We report a quantitative, two-antibody sandwich immunoassay for phosphinothricin acetyltransferase (PAT), the selectable marker protein. The method yielded a standard curve with a working range of 0 to 5 ng PAT per mL extract. Replicate absorbance values for standards within a single assay showed a coefficient of variation typically less than 5 percent. Over three separate assays, the coefficient of variation for the slope and y-intercept of the standard curve was 3.8 and 3.7 percent, respectively. TransgenicBrassica napus L. seed was used to demonstrate the utility of the assay. Non-transgenic seed extracts did not show a positive immunoassay signal. Determinations of the PAT enzyme conducted on spiked non-transgenic seed extracts repeated in three separate assays fell in the acceptable range of 80 to 120 percent recovery. Transgenic canola seed, analyzed in three separate assays, showed a mean PAT enzyme content of 403 ng/g with a standard error of 19 ng/g and a coefficient of variation of 8.1 percent. The method has also been applied to several other tissues and processed products of canola, maize, and tobacco.     

Semi-Automated Detection of Cerebral Microbleeds on 3.0 T MR Images

Cerebral microbleeds are associated with vascular disease and dementia. They can be detected on MRI and receive increasing attention. Visual rating is the current standard for microbleed detection, but is rater dependent, has limited reproducibility, modest sensitivity, and can be time-consuming. The goal of the current study is to present a tool for semi-automated detection of microbleeds that can assist human raters in the rating procedure. The radial symmetry transform is originally a technique to highlight circular-shaped objects in two-dimensional images. In the current study, the three-dimensional radial symmetry transform was adapted to detect spherical microbleeds in a series of 72 patients from our hospital, for whom a ground truth visual rating was made by four raters. Potential microbleeds were automatically identified on T2*-weighted 3.0 T MRI scans and the results were visually checked to identify microbleeds. Final ratings of the radial symmetry transform were compared to human ratings. After implementing and optimizing the radial symmetry transform, the method achieved a high sensitivity, while maintaining a modest number of false positives. Depending on the settings, sensitivities ranged from 65%–84% compared to the ground truth rating. Rating of the processed images required 1–2 minutes per participant, in which 20–96 false positive locations per participant were censored. Sensitivities of individual raters ranged from 39%–86% compared to the ground truth and required 5–10 minutes per participant per rater. The sensitivities that were achieved by the radial symmetry transform are similar to those of individual experienced human raters, demonstrating its feasibility and usefulness for semi-automated microbleed detection.     

Preoperative and longitudinal serum levels of CA 125 and CA 15.3 in patients with breast cancer

Serum levels of ovarian carcinoma antigen (CA 125) and breast carcinoma antigen (CA 15.3) were determined in 237 patients with breast carcinoma, 121 before any therapy and 116 after initial treatment, during uneventful follow-up or at the time of relapse. The aim was to assess how often the CA 125 test failed, i.e., was false-negative in patients in whom the CA 15.3 test was true-positive and, more important, whether it gave diagnostic information in patients in whom the CA 15.3 test failed. Before surgery or other initial therapy, serum CA 125 and CA 15.3 gave similar information in 85.1 percent of the patients: true-positive in 4.1 percent and false negative in 81.0 percent: CA 125 gave less information in 13.2 percent; and more information in only 1.7 percent. During follow-up, serum CA 125 and CA 15.3 gave similar information in 73.3 percent of the patients: true-positive (i.e., rising persistently from a nadir or elevated above 65 U/ml) in 23.3 percent, true-negative in 36.2 percent, and false-negative in 13.8 percent; CA 125 gave less information in 25.0 percent: false negative in 22.4 percent and false-positive in 2.6 percent; and more information in only 1.7 percent. Therefore, the CA 125 test appears useless for staging and is redundant when the CA 15.3 test is employed, for management of patients with breast cancer.     

Assessing Differential Expression in Two-Color Microarrays: A Resampling-Based Empirical Bayes Approach

Microarrays are widely used for examining differential gene expression, identifying single nucleotide polymorphisms, and detecting methylation loci. Multiple testing methods in microarray data analysis aim at controlling both Type I and Type II error rates; however, real microarray data do not always fit their distribution assumptions. Smyth''s ubiquitous parametric method, for example, inadequately accommodates violations of normality assumptions, resulting in inflated Type I error rates. The Significance Analysis of Microarrays, another widely used microarray data analysis method, is based on a permutation test and is robust to non-normally distributed data; however, the Significance Analysis of Microarrays method fold change criteria are problematic, and can critically alter the conclusion of a study, as a result of compositional changes of the control data set in the analysis. We propose a novel approach, combining resampling with empirical Bayes methods: the Resampling-based empirical Bayes Methods. This approach not only reduces false discovery rates for non-normally distributed microarray data, but it is also impervious to fold change threshold since no control data set selection is needed. Through simulation studies, sensitivities, specificities, total rejections, and false discovery rates are compared across the Smyth''s parametric method, the Significance Analysis of Microarrays, and the Resampling-based empirical Bayes Methods. Differences in false discovery rates controls between each approach are illustrated through a preterm delivery methylation study. The results show that the Resampling-based empirical Bayes Methods offer significantly higher specificity and lower false discovery rates compared to Smyth''s parametric method when data are not normally distributed. The Resampling-based empirical Bayes Methods also offers higher statistical power than the Significance Analysis of Microarrays method when the proportion of significantly differentially expressed genes is large for both normally and non-normally distributed data. Finally, the Resampling-based empirical Bayes Methods are generalizable to next generation sequencing RNA-seq data analysis.     

A Rapid, Presumptive Procedure for the Detection of Salmonella in Foods and Food Ingredients

A rapid detection procedure was developed in which a lysine-iron-cystine-neutral red (LICNR) broth medium, originally described by Hargrove et al. in 1971, was modified and used to detect the presence of viable Salmonella organisms in a variety of foods, food ingredients, and feed materials by using a two-step enrichment technique. Tetrathionate broth was used to enrich samples with incubation at 41 C for 20 hr, followed by transfer to LICNR broth and incubation at 37 C for 24 hr for further enrichment and for the detection of Salmonella organisms by color change. One hundred ten samples representing 18 different sample types were evaluated for the presence of viable Salmonella. Ninety-four percent of the samples found to be presumptive positive by this method were confirmed as positive by a culture method. Fluorescent-antibody results also compared closely. A second study was conducted under quality-control laboratory conditions by using procedures currently employed for Salmonella detection. One hundred forty-three samples representing 19 different sample types were evaluated for the presence of viable Salmonella. No false negatives were observed with the rapid-detection method. The usefulness of the LICNR broth procedure as a screening technique to eliminate negative samples rapidly and to identify presumptive positive samples for the presence of viable Salmonella organisms was established in this laboratory.     

Quantitative Urine Culture by Surface Drop Method

A simple drop method for quantitative urine culture was developed and tested in comparison with standard methods for bacterial urinary counts. In a group of 452 urines all yielding Escherichia coli, 74 showed counts of more than 100,000 colonies, and 16 showed counts between 10,000 and 100,000 colonies per ml. Of these 90 urines, 3 of the 16 in the doubtful group were false negative with the drop method. Another 7 urines in the total number of 452 showed discrepancies, but, because all would have been repeated, the second urine sample would have corrected the primary result. The ease and cleanliness of the method render it a suitable technique for screening normal and patient populations. The method was applied on a population sample of 1,330 persons from whom unwashed mid-stream urine was collected and yielded figures comparable with results published in the literature. The method discriminates between steps of 10-fold difference, whereas more accurate count methods show a standard error of +/-25% and are reliable in a double dilution series.