Binomial Confidence Limits Research Articles

Magnetic resonance imagingfollowing the demonstration of a normal common bile duct on ultrasound in children with suspected choledocholithiasis: what is the benefit?

The role of MRI in evaluating children with an in situ gallbladder and suspected choledocholithiasis following a negative or inconclusive US is unclear. To determine whether MRI benefits children with suspected choledocholithiasis and a normal common bile duct (CBD) without stones on US. We conducted a retrospective 10-year review of paired US and MRI (within 10days) in children 18years or younger with suspected choledocholithiasis. With MRI as a reference standard, two reviewers independently evaluated the images for CBD diameter, choledocholithiasis, cholelithiasis and pancreatic edema. Serum lipase was recorded. We calculated exact binomial confidence limits for test positive predictive values (PPVs) and negative predictive values (NPVs) using R library epiR. Of 87 patients (46 female, 41 male; mean age 14years, standard deviation [SD] 4.6years; mean interval between US and MRI 1.6days, SD 1.8days), 55% (48/87) had true-negative US, without CBD dilation/stones confirmed on MRI; 5% (4/87) had false-positive US showing CBD dilatation without stones, not confirmed on MRI; 33% (29/87) had true-positive US, with MRI confirming CBD dilatation; and 7% (6/87) had false-negative US, where MRI revealed CBD stones without dilatation (2 patients) and CBD dilatation with or without stones (4 patients). Patients with false-negative US had persistent or worsening symptoms, pancreatitis or SCD. The overall US false-negative rate was 17% (6/35). Normal-caliber CBD on US without stones had an NPV of 89% (48/54, 95% confidence interval: 0.77-0.96). MRI adds little information in children with a sonographically normal CBD except in the setting of pancreatitis or worsening clinical symptoms.Further evaluation is warranted in children with elevated risk of stone disease.

SOURCE AND SEASONALITY OF EPIZOOTIC MYCOPLASMOSIS IN FREE-RANGING PRONGHORN (ANTILOCAPRA AMERICANA).

Mycoplasma bovis is an economically important bacterial pathogen of cattle (Bos taurus) and bison (Bison bison) that most commonly causes pneumonia, polyarthritis, and mastitis. It is prevalent in cattle and ranched bison; however, infections in other species are rare. In early 2019, we identified M. bovis in free-ranging pronghorn (Antilocapra americana) in northeastern Wyoming. Here, we report on additional pronghorn mortalities caused by M. bovis, in the same approximately 120-km2 geographic region 1 yr later. Genetic analysis by multilocus sequence typing revealed that the mortalities were caused by the same M. bovis sequence type, which is unique among all sequence types documented thus far in North America. To explore whether pronghorn maintain chronic infections and begin assessing M. bovis status in other sympatric species, we used PCR testing of nasal swabs to opportunistically survey select free-ranging ungulates. We found no evidence of subclinical infections in 13 pronghorn sampled from the outbreak area (upper 95% binomial confidence limit [bCL], ∼24.7%) or among 217 additional pronghorn (upper 95% bCL, ∼1.7%) sampled from eight additional counties in Wyoming and 10 in Montana. All mule deer (Odocoileus hemionus; n=231; upper 95% bCL, ∼1.6%) sampled from 11 counties in Wyoming also were PCR negative. To assess the potential for environmental transmission, we examined persistence of M. bovis in various substrates and conditions. Controlled experiments revealed that M. bovis can remain viable for 6 h in shaded water and 2 h in direct sunlight. Our results indicate that environmental transmission of M. bovis from livestock to pronghorn is possible and that seasonality of infection could be due to shared resources during late winter. Further investigations to better understand transmission dynamics, to assess population level impacts to pronghorn, and to determine disease risks among pronghorn and other ungulate taxa appear warranted.

Diagnostic accuracy of the CxPREVENTIVE Colon model for early detection of colorectal cancer.

e15518 Background: Despite different available methods for colorectal cancer (CRC) screening and their proven benefits, morbidity, and mortality of this malignancy are still high, partly due to technical limitations and low compliance with screening. The aim of the present study was to assess the diagnostic accuracy for early detection of CRC using a modeling algorithm based on multiple blood and urine biomarkers. Methods: In this retrospective cohort study, clinical and blood and urine markers-based algorithms with predefined cutoff values were applied to a generally healthy asymptomatic outpatient cohort of adults aged 50 years or older undergoing colonoscopy and histopathology for routine colorectal cancer screening. We used a modeling algorithm based on two different frameworks (Multiple Biomarkers Disease Activity Algorithm MBDAA [Bioprognos], and Artificial Intelligence Recursive Algorithm AIRA [Mintlot] both in Barcelona, Spain). Both algorithms compute information from a wide number of analytes, tumor markers (AFP, CA 19.9, CA 72.4, CA 125, CEA, Cyr61, NGAL, EGFR and 8-OHdG), and additional clinical data (age, weight, height, and BMI). MBDAA includes Barcelona Criteria (four criteria to correctly interpret the cause of the increase in tumor markers, benign or malignant, defined by the Spanish Society of Clinical Biochemistry and Molecular Pathology, Commission of Biological Markers of Cancer). To assess the association between the modelling algorithm and downstream diagnosis we used logistic regression to compute receiver operating characteristic curves (ROC). Exact binomial confidence limits were calculated to test accuracy, sensitivity, and specificity. Results: 221 people (median age 63 yr. [IQR 49-77]; 107 [49%] women and 114 [51%] men) who underwent colonoscopy at the Juan Ramón Jiménez Hospital (Huelva, Spain), were included in this analysis. Based on colonoscopy and histopathologic findings, CRC was diagnosed in 45 (20%) patients, colonic polyposis in 56 (25%), inflammatory bowel disease in 37 (17%), and absence of pathological findings (control group) was seen in 83 (38%). The diagnostic intervention for CRC yielded an area under the curve (AUC) of 1 among the entire specimen set, accuracy 1 (95% CI 0.996,1), Se 1 (0.988, 1) and Sp 1 (0.997, 1). Besides, the algorithm also performed very well in the identification of polyps with an accuracy 1 (95% CI, 0.967 to 1), Se of 1 (0.991, 1) and of Sp 1 (0.996, 1), as well in the diagnosis of inflammatory bowel disease with an accuracy of 1 (0.968 to 1), Se of 1 (0.986, 1) and Sp of 1 (0.997, 1). Conclusions: Using colonoscopy as a gold standard, our data suggest that an innovative newly designed non-invasive blood and urine-based biomarker algorithm CxPREVENTIVE Colon may provide a timely diagnosis of CRC with very high accuracy. Our findings warrant further investigation, and we are planning large-scale (n 10,000), fully powered study to inform clinical practice.

Diagnostic accuracy of the CxPREVENTIVE breast model for early detection of breast cancer.

e13578 Background: Despite different available methods for breast cancer (BC) screening (mainly mammographies for ages between 50 and 65 yr.), and their proven benefits, morbidity, and mortality of this malignancy are still high, partly due to technical limitations and low compliance with screening. The aim of the present study was to assess the diagnostic accuracy for early detection of BC using a modeling algorithm based on multiple blood and urine biomarkers. Methods: In this retrospective cohort study, clinical and blood and urine markers-based algorithms with predefined cutoff values were applied to a generally healthy asymptomatic outpatient cohort of women aged 23 years or older undergoing mammography and histopathology for routine breast cancer screening. We used a modeling algorithm based on two different frameworks (Multiple Biomarkers Disease Activity Algorithm MBDAA [Bioprognos], and Artificial Intelligence Recursive Algorithm AIRA [Mintlot] both in Barcelona, Spain). Both algorithms compute information from a wide number of analytes, tumor markers (CA 15.3, CEA, EGFR, NGAL, NSE and 8-OHdG), and additional clinical data (age, weight, height, and BMI). MBDAA includes Barcelona Criteria (four criteria to correctly interpret the cause of the increase in tumor markers, benign or malignant, defined by the Spanish Society of Clinical Biochemistry and Molecular Pathology, Commission of Biological Markers of Cancer). To assess the association between the modelling algorithm and downstream diagnosis we used logistic regression to compute receiver operating characteristic curves (ROC). Exact binomial confidence limits were calculated to test accuracy, sensitivity, and specificity. Results: 123 women (median age 48 yr. [IQR 40-63]) who underwent mammography at the Juan Ramón Jiménez Hospital (Huelva, Spain), were included in this analysis. Based on mammography and histopathologic findings, BC was diagnosed in 61 (49.5%) women, and absence of pathological findings (control group) was seen in 62 (51.5%). The diagnostic intervention for BC yielded an area under the curve (AUC) of 1 among the entire specimen set, accuracy 1 (95% CI 0.990,1), Se 1 (0.991, 1) and Sp 1 (0.991, 1). Conclusions: Using mammography as a gold standard, our data suggest that an innovative newly designed non-invasive blood and urine-based biomarker algorithm CxPREVENTIVE Breast may provide a timely diagnosis of BC with very high accuracy, especially for those women under 50 and over 65yr., where up to 60% of all BC are concentrated. Our findings warrant further investigation, and we are planning large-scale (n 10,000), fully powered study to inform clinical practice.

Male-to-female ratios among NTDs and women's periconceptional intake of folic acid.

About a decade ago, a hypothesis was put forward to explain the preponderance of females among neural tube defect (NTD) fetuses. That hypothesis predicts that a woman's higher levels of early gestational intake of methyl groups, such as folic acid, will be associated with lesser male-to-female ratio differences in NTD-affected births, specifically less preponderance of females. We explored this hypothesis in four distinct studies that investigated human NTDs, obtained information on folic acid, and capitalized on timing of folic acid fortification by investigating data that were collected both prior to and after the 1998 initiation of U.S. mandatory folic acid fortification of grains. We analyzed data from four population-based case control studies conducted in California for birth years spanning 1987-2011. Two studies were conducted before folic acid fortification of the U.S. food supply. Each of the four studies included interviews of women who either had NTD-affected pregnancies (cases) or who did not have a pregnancy affected by a birth defect (controls). In each study, information on periconceptional supplement use was elicited. We explored male-to-female ratios and 95% binomial confidence limits in each data set. Our analyses of two case-control studies performed prior to and two performed post mandatory folate fortification in the United States showed that more NTD-affected fetuses were female in the first two studies. In the studies done before fortification, the frequency of females was even greater among those pregnancies without folic acid supplementation. Our findings suggest folic acid may differentially reduce risk of NTDs among female fetuses.

The description of a method for accurately estimating creatinine clearance in acute kidney injury

BackgroundAcute kidney injury (AKI) is a common and serious condition encountered in hospitalized patients. The severity of kidney injury is defined by the RIFLE, AKIN, and KDIGO criteria which attempt to establish the degree of renal impairment. The KDIGO guidelines state that the creatinine clearance should be measured whenever possible in AKI and that the serum creatinine concentration and creatinine clearance remain the best clinical indicators of renal function. Neither the RIFLE, AKIN, nor KDIGO criteria estimate actual creatinine clearance. Furthermore there are no accepted methods for accurately estimating creatinine clearance (K) in AKI. Study designThe present study describes a unique method for estimating K in AKI using urine creatinine excretion over an established time interval (E), an estimate of creatinine production over the same time interval (P), and the estimated static glomerular filtration rate (sGFR), at time zero, utilizing the CKD-EPI formula. Using these variables estimated creatinine clearance (Ke)=E/P * sGFR. Setting and participantsThe method was tested for validity using simulated patients where actual creatinine clearance (Ka) was compared to Ke in several patients, both male and female, and of various ages, body weights, and degrees of renal impairment. These measurements were made at several serum creatinine concentrations in an attempt to determine the accuracy of this method in the non-steady state. In addition E/P and Ke was calculated in hospitalized patients, with AKI, and seen in nephrology consultation by the author. In these patients the accuracy of the method was determined by looking at the following metrics; E/P>1, E/P<1, E=P in an attempt to predict progressive azotemia, recovering azotemia, or stabilization in the level of azotemia respectively. In addition it was determined whether Ke<10ml/min agreed with Ka and whether patients with AKI on renal replacement therapy could safely terminate dialysis if Ke was greater than 5ml/min. Outcomes and resultsIn the simulated patients there were 96 measurements in six different patients where Ka was compared to Ke. The estimated proportion of Ke within 30% of Ka was 0.907 with 95% exact binomial proportion confidence limits. The predictive accuracy of E/P in the study patients was also reported as a proportion and the associated 95% confidence limits: 0.848 (0.800, 0.896) for E/P<1; 0.939 (0.904, 0.974) for E/P>1 and 0.907 (0.841, 0.973) for 0.9<E/P<1.1. Ke<10ml/min correlated very well with Ka, while Ke>5ml/min accurately predicted the ability to terminate renal replacement therapy in AKI. LimitationsInclude the need to measure urine volume accurately. Furthermore the precision of the method requires accurate estimates of sGFR, while a reasonable measure of P is crucial to estimating Ke. ConclusionsThe present study provides the practitioner with a new tool to estimate real time K in AKI with enough precision to predict the severity of the renal injury, including progression, stabilization, or improvement in azotemia. It is the author's belief that this simple method improves on RIFLE, AKIN, and KDIGO for estimating the degree of renal impairment in AKI and allows a more accurate estimate of K in AKI.

Technical Reproducibility of Single-Nucleotide and Size-Based DNA Biomarker Assessment Using DNA Extracted from Formalin-Fixed, Paraffin-Embedded Tissues

DNA extracted from formalin-fixed, paraffin-embedded (FFPE) tissues has been used in the past to analyze genetic polymorphisms. We evaluated the technical reproducibility of different types of assays for gene polymorphisms using DNA extracted from FFPE material. By using the MassARRAY iPLEX system, we investigated polymorphisms in DPYD (rs1801159 and rs3918290), UMPS (rs1801019), ERCC1 (rs11615), ERCC1 (rs3212986), and ERCC2 (rs13181) in 56 FFPE DNA samples. By using PCR, followed by size-based gel electrophoresis, we also examined TYMS 5' untranslated region 2R/3R repeats and GSTT1 deletions in 50 FFPE DNA samples and 34 DNAs extracted from fresh-frozen tissues and cell lines. Each polymorphism was analyzed by two independent runs. We found that iPLEX biomarker assays measuring single-nucleotide polymorphisms provided consistent concordant results. However, by using FFPE DNA, size-based PCR biomarkers (GSTT1 and TYMS 5' untranslated region) were discrepant in 32.7% (16/49, with exact 95% CI, 19.9%-47.5%; exact binomial confidence limit test) and 4.2% (2/48, with exact 95% CI, 0.5%-14.3%) of cases, respectively, whereas no discrepancies were observed using intact genomic DNA. Our findings suggest that DNA from FFPE material can be used to reliably test single-nucleotide polymorphisms. However, results based on size-based PCR biomarkers, and particularly GSTT1 deletions, using FFPE DNA need to be interpreted with caution. Independent repeated assays should be performed on all cases to assess potential discrepancies.

An alternative injection technique for performing MR ankle arthrography: the lateral mortise approach

This study evaluates whether the recently described lateral mortise (LM) approach to therapeutic ankle injections can also be used to inject the ankle prior to magnetic resonance arthrography (MRA) without impairing the evaluation of the anterior talofibular ligament (ATFL). An IRB-approved, retrospective review of ankle MRAs performed using the LM approach between April 2009 and April 2011 was conducted. The MRAs were independently evaluated by three musculoskeletal radiologists for: ATFL assessment (well assessed, limited or unable to assess), amount of fluid in the anterolateral soft tissues (none to large), and capsular distention (underdistended to overdistended). Patient age, gender, fluoroscopy time, injection location, degree of ankle arthritis, and ankle joint narrowing on radiographs were recorded. Statistical analysis was performed using exact binomial confidence limits. Fifteen MRAs were successfully performed on 13 patients (mean age: 27 years, 11 male, 2 female). Mean fluoroscopic time was 39 s (range 9–108) and mean volume injected was 7 mL (range 5–9 mL). The ATFL was well assessed on all MRAs. A moderate to large amount of fluid was noted in the anterolateral soft tissues on 5 out of 15 MRAs. No ankle joints were underdistended, but 3 out of 15 were overdistended. Since the ATFL is inferior to the location used for the LM injection, the interpretation of the ankle MRA, specifically ATFL evaluation, was not compromised in any patient. Therefore, the LM approach can be used as an alternative to the anteromedial approach for ankle MRA without sacrificing diagnostic quality.

Prevalence of Batrachochytrium dendrobatidis infection is extremely low in direct-developing Australian microhylids

The emerging infectious disease chytridiomycosis has been implicated in declines and disappearances of amphibian populations around the world. However, susceptibility to infection and the extent of pathological effects of infection vary among hosts, and species with life histories that include parental care of direct-developing terrestrial eggs may tend to be less susceptible. We examined samples from a total of 595 individuals of 9 species of direct-developing Australian frogs in the family Microhylidae for the presence of infection by Batrachochytrium dendrobatidis (Bd). Between 1995 and 2004, 336 samples were collected; 102 of these were analysed histologically and 234 were tissues stored in alcohol, which were examined using diagnostic quantitative PCR (qPCR). Swab samples were collected from 259 frogs from 2005 to 2008 and were examined using qPCR. None of the 595 samples showed evidence of infection by Bd. If these data are regarded as a single sample representative of Australian microhylids, the upper 95% binomial confidence limit for the prevalence of infection in frogs of this family is 0.0062 (<1%). Even if only the data from the more powerful diagnostic qPCR tests are used, the upper 95% confidence limit for prevalence is 0.0075 (<1%). Our data suggest that Australian microhylids have a very low prevalence of infection by Bd in nature, and thus are either not susceptible, or are only slightly susceptible, to chytridiomycosis. This could be due solely to, or in combination with, low rates of transmission and to factors that promote resistance to infection, including ecological or behavioural characteristics, innate immune functions such as antimicrobial skin peptides, or antimicrobial symbionts in skin flora.

Later Outcomes and Alpha/Beta Estimate From Hypofractionated Conformal Three-Dimensional Radiotherapy Versus Standard Fractionation for Localized Prostate Cancer

Now that the follow-up time has exceeded 5 years, an estimate of the α/β ratio can be presented. The additional late outcomes in patients treated with three-dimensional conformal external beam radiotherapy for localized prostate cancer using a hypofractionated vs. a standard fractionation regimen are reported from this prospective nonrandomized contemporary comparison. A total of 114 nonrandomized patients chose hypofractionation delivered in 20 fractions of 3 Gy or 3.15 Gy (mean 3.06 Gy) for localized prostate cancer within a median overall time of 32 days (range, 29-49) using four fractions weekly. A total of 160 comparable patients were contemporarily treated within a median of 55 days (range 49-66). The median follow-up was 66 months (range, 24-95) for the hypofractionated arm and 63 months (range, 36-92) for the standard arm. The percentage of patients in the low-, medium-, and high-risk groups was 36%, 46%, and 18% in the hypofractionated arm and 44%, 50%, and 6% in standard arm (2 Gy), respectively. The 5-year actuarial biochemical absence of disease (prostate-specific antigen nadir+ 2 ng/mL) and disease-free survival rate was the same at 89% in both arms, making the α/β calculation unambiguous. The point ratio of α/β was 1.86 (95% confidence interval, 0.7-5.1 Gy). The 95% confidence interval was determined entirely by the binomial confidence limits in the numbers of patients. Rectal reactions of grade 3 and 4 occurred in 1 of 114 (hypofractionated) and 2 of 160 (standard) patients. The presented three-dimensional conformal regimen was acceptable, and the α/β value was 1.8, in agreement with other very recent low meta-analyses (reviewed in the "Discussion" section).

Surveillance for West Nile Virus in Wild Birds from Northern Europe

A total of 1935 migratory birds from 104 different species were captured in southeastern Sweden in 2005-2006 and tested for antibodies against West Nile virus (WNV). Overall, 46 birds (2.4%; binomial confidence limits, 1.8-3.2) were positive by blocking-ELISA, but only 2 (0.10%; binomial confidence limits, 0.0-0.4) had antibodies detectable by both blocking-ELISA and WNV neutralization test. ELISA-positive birds included long- and short-distance migrants likely exposed to WNV while wintering in or migrating through areas enzootic for WNV. Exposure to a cross-reactive Flavivirus was suspected for short-distance migrants of the Turdidae family, but no cross-neutralization with tick-borne encephalitis and Usutu viruses was observed.

An easy to use method to approximate Poisson confidence limits

Despite the ever larger choice of softwares and statistical packages allowing fast and accurate computation of binomial and Poisson confidence limits, there is always a need for a simple and reliable formula allowing non-computerized computations. The method proposed in this paper is derived from the Freeman and Tukey's variance stabilizing transformation for a random Poisson variable and adjusted for giving the best fit with the exact Poisson values. Despite its simplicity, allowing its use in any circumstances, this method provides very satisfactory results and a much better fit than classical formula based on the normal approximation, even if a continuity correction is used. It allows computation of Poisson confidence limits both for count or rates and proportions.

A Library of Spirooxindoles Based on a Stereoselective Three-Component Coupling Reaction

A collection of structurally complex and chemically diverse small molecules is a useful tool to explore cell circuitry. In this article, we report the split-pool synthesis of more than 3000 spirooxindoles on high capacity macrobeads. The key reaction to assemble the spirooxindole core stereoselectively is a Lewis acid variant of the Williams' three-component coupling. After formation, the skeleton was elaborated using Sonogashira couplings, amide forming reactions, and N-acylations of gamma-lactams. The final library was analyzed by sampling individual macrobeads and by using binomial confidence limits. It was determined that at least 82% of the library compounds should have better than 80% purity. To demonstrate the utility of our discovery process, a high-throughput chemical genetic modifier screen was performed using stock solutions of the resultant products. A number of positives were identified as enhancers of the cellular actions of latrunculin B, an actin polymerization inhibitor. Through resynthesis, we confirmed one of the positives and demonstrated that, in yeast cells, it has an EC50 in the sub-micromolar range.

Sample sizes for improved binomial confidence intervals

Sample size equations are reviewed for different types of confidence intervals on a binomial success probability. Based on recommendations for improved binomial confidence limits given by Brown et al. (Statist. Sci. 16 (2001) 101), the intervals expand upon or enhance the traditional Wald-type interval. Some useful sample size relations appear.

Confidence limits of species proportions in microfossil assemblages

We analyzed the confidence limits of benthic foraminiferal counts obtained from fossil deep-sea assemblages to figure out the optimum number of specimens needed for a reliable interpretation of species proportions. Precision and reliability are analyzed by calculating the binomial confidence limits. We demonstrate that in studies based on the interpretation of the proportional distribution of only the dominant taxa, counts of as low as 100 specimens are sufficient. Studies, however, that aim to investigate species diversity patterns usually require higher counts. Generally, we suggest that percent abundance given in micropaleontological studies should include the binomial error estimate.

Discontinuation of chemoprophylaxis against Pneumocystis carinii pneumonia in patients with HIV infection. HIV Outpatient Study (HOPS) Investigators.

HIV-infected patients with sustained immunologic improvement from antiretroviral therapy may be able to discontinue chemoprophylaxis against Pneumocystis carinii pneumonia (PCP). To compare PCP incidence in HIV-infected patients who had sustained CD4+ lymphocyte counts greater than 200 cells/mm3 and who either discontinued or continued PCP prophylaxis. Nonrandomized prospective cohort study. 10 HIV clinics in eight U.S. cities. 146 patients had follow-up visits for a mean of 18.2 months after discontinuation of PCP prophylaxis, and 345 patients who continued PCP prophylaxis had follow-up visits for a mean of 14.0 months. Incidence of PCP. Patients who discontinued PCP prophylaxis had higher maximum and minimum CD4+ cell counts and lower vira loads than patients who continued PCP prophylaxis. Pneumocystis carinii pneumonia did not develop in either group (upper 95% exact binomial confidence limit of incidence for those who discontinued PCP prophylaxis, 2.3/100 person-years). Discontinuation of PCP chemoprophylaxis may be appropriate for some HIV-infected ambulatory patients.

RELIABILITY VALIDATION VIA SUCCESS-FAILURE TESTING: A HIDDEN CONTROVERSY

[This abstract is based on the author's abstract.] Binomial confidence limit expressions are shown in terms of the cumulative binomial distribution, which is discrete, and in equivalent representations of either the beta-distributional or F-distributio..

Experience with a broth culture technique for diagnosis of bacterial keratitis.

To determine if a broth culture technique is a practical means for bacteriological investigation of keratitis. Twenty-seven eyes of 27 patients with a clinical diagnosis of bacterial keratitis were included in a prospective and non-comparative study at a Danish referral hospital. A corneal scrape was inoculated directly into broth medium which was transferred to the diagnostic laboratory for incubation and subculture. Culture was negative in 4 patients, and 19 of the remaining 23 patients had a pure growth of either Pseudomonas aeruginosa (n = 8), Staphylococcus aureus (n = 2), Streptococcus pneumoniae (n = 2), Haemophilus influenzae biotype III (n = 1), Moraxella species (n = 1), Corynebacterium species (n = 1), or coagulase-negative staphylococci (n = 4). In 4 patients there was a mixed gram-positive growth. There was no association between microbiological findings and previous topical antibiotic therapy. Contamination and lack of quantitative assessment of growth proved not to be a problem. By broth culture technique we identified a definite pathogen (P. aeruginosa, S. aureus or S. pneumoniae) in 44% of patients (95% binomial confidence limits: 25-65%). The technique may replace the standard technique of direct plate culture under circumstances where it is difficult to keep a supply of fresh media or transport inoculated plates.

Adult Chinook Salmon Behavior and Survival after Catch and Release from Purse-Seine Vessels in Johnstone Strait, British Columbia

In British Columbia, chinook salmon Oncorhynchus tshawytscha are commonly taken in purse-seine fisheries directed at other salmon species, but the need to conserve chinook salmon may reduce the opportunities for such fisheries to operate. To test the feasibility of a nonretention fishery (i.e., release) for chinook salmon, we used ultrasonic telemetry to estimate the survival rates of chinook salmon caught and released from purse-seine vessels in Johnstone Strait, British Columbia. From 1990 to 1992, we tracked 47 fish for durations ranging from 2 h 1 min to 32 h 48 min (mean, 16 h 48 min). For the first 24 h after release, the survival rate for all years combined was estimated to be 77% with 95% binomial confidence limits of 62% and 87%. Mortality was positively associated with longer landing time. Chinook salmon that survived spent between 57–64% of the next 24 h at depths less than 50 m where they were vulnerable to recapture by commercial purse-seine gear.

Simple SAS macros for the calculation of exact binomial and Poisson confidence limits

Statistical analysis using confidence intervals is now a preferred approach in the medical literature, and confidence limits for binomial proportions and Poisson counts are commonly required. Normal approximations of varying accuracy are often used in such situations and it is not generally realised that non-iterative exact solutions are available. This paper shows that the exact binomial and Poisson confidence limits can be expressed very simply in terms of the inverse beta and inverse gamma distributions, and describes two macros in the SAS programming language to perform the computations. The exact solutions are compared with some approximations and further applications of the techniques are described.