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At least 973 records · Page 54Linked to original sources
PubMed2003

Simple optical fibre biosensor based on immobilised enzyme for monitoring of trace heavy metal ions.

A simple optical fibre biosensor based on immobilised enzyme for monitoring of trace heavy metal ions has been developed. The biosensor recognition system was designed based on the inhibition of urease activity, where the urease is immobilised on ultrabind membrane. The studies of inhibition by the heavy metal ions Hg(II), Ag(I), Cu(II), Ni(II), Zn(II), Co(II) and Pb(II) were performed using a fibre-optic biosensor configuration, where the pH change resulting from the bio-catalytic hydrolysis of urea was monitored at the wavelength 615 nm spectroscopically, using commercial pH indicator strip before and after the exposure to the heavy metal ions. The immobilised urease was regenerated by l-cysteine. The linear response range between 1 x 10(-9)-1 x 10(-5) M and the limit of detection 1 x 10(-9 )M (0.2 microg/L) for Hg(II) ions was achieved by employing the flow method. The optimisation of experimental parameters, including flow method, is also discussed.

Biosensing Techniques↗
PubMed1995

Evaluation of the E test system versus a microtitre broth method for antifungal susceptibility testing of yeasts against fluconazole and itraconazole.

The E test strip (AB Biodisk, Solna, Sweden) as an antimicrobial susceptibility testing method is a new and promising tool with broad application in microbiology. This method is less labour intensive than broth dilution methods and may be useful for testing individual clinical isolates. In contrast to several publications comparing E test antibacterial strips with NCCLS reference methods, there is little information about the performance of E test antifungal strips. This study compared fluconazole and itraconazole MICs obtained by E test with a microbroth dilution method performed to NCCLS guidelines. Fluconazole and itraconazole E test results exhibited good correlation with the broth microdilution (82% and 81% agreement within +/- 1 two-fold dilution, respectively). The E test is easy to perform and generates MICs for Candida species in 24 h.

Antifungal Agents↗
PubMed1986

Evaluation of four modern home blood glucose meters including two memory meters.

Four battery-operated blood glucose reflectance meters have been tested for precision, accuracy, and convenience of use. Parallel assays on 50 venous blood samples comparing a meter and a glucose oxidase reference method gave the following regression line parameters and correlation coefficients: Diatron Easytest (Eastlords Electronics Ltd), y = 0.76x + 1.23, r = 0.93; Glucochek II (Medistron Ltd), y = 0.90x - 0.01, r = 0.98; Hypocount MX (Hypoguard Ltd), y = 0.97x - 0.14, r = 0.98; Reflolux (Boehringer Mannheim GmbH). y = 0.97x + 0.18, r = 0.99. Reflolux has to be recalibrated with a barcoded film strip for each new test strip tin and is the most precise and accurate meter. Glucochek II using both whole and half BM Test Glycemie 20-800R test strips, showed similarly good precision, and was the simplest meter to use containing only one moving operational part. Hypocount MX is the smallest of these meters, is easy to use and has a memory which can store up to 10 blood glucose readings. The memory of the Diatron Easytest is bigger and easier to use since it stores and automatically updates 25 successive glucose values; however, this was the least accurate and least precise of the meters.

Blood Glucose↗
PubMed1996

Methodological considerations in GCF sampling with paper strips: poor recovery of uncomplexed elastase.

The purpose of this study was to assess the recovery of certain proteins from paper strips used for sampling of gingival crevicular fluid (GCF). During a period of 60 min, proteins were eluent in isotonic phosphate-buffered saline, pH 7.4, without detergent. This eluent did not lyse neutrophils applied to the strips, which might otherwise contribute intracellular substances-, e.g., elastase to the GCF samples. The proteins applied (MW 12-725 kD) were satisfactorily recovered (about 90%). However, free neutrophil elastase, unlike elastase complexed with alpha-2-macroglobulin, could not be recovered from the paper strips. Strips made of polyvinylidene difluoride (Durapore) were also tested and 31% of the applied pure elastase was recovered from them. A comparison of measurements made with a Periotron 6000 on Periopaper and Durapore strips, showed that the values obtained with Durapore were too low for accurate measurements of small volumes of fluid. On the whole, when the elution was made in isotonic buffers at neutral pH and without detergents, the recovery of most proteins was satisfactory and reproducible, and independent of MW in the tested range. However, the study also showed poor recovery of uncomplexed elastase.

Buffers↗
PubMedDate not supplied

Accuracy of two systems for blood glucose monitoring without a meter (Chemstrip/Visidex).

Blood specimens collected from 159 campers were tested using Visidex (VD) (Ames Company, Elkhart, Indiana) and Chemstrip (CS) (Bio-Dynamics, Boehringer Mannheim, Indianapolis, Indiana) compared with glucose analyzer (GA) results. Readers were physicians, two with no prior experience using either strip and two with some experience using CS. Subsequently, 30 clinic patients and 4 staff contributed random specimens that were read by a trained novice as 68 discrete samples and compared with GA results. In both studies readers did not place blood on the strips and were thus blinded as to source and the possible previous reading with the other strip. Correlations of VD and CS with GA for camp and clinic data were calculated. Data were compared for reliability and errors greater than 20% of reference values (GA) were compared for VD and CS. CS correlated better with GA than did VD estimates. Reliability was also significantly greater for CS than for VD readings. Both of these visually read methods provided clinically useful estimates of glycemia.

Autoanalysis↗
PubMed1993

Laboratory assessment of five glucose meters designed for self-monitoring of blood glucose concentration.

We describe a laboratory assessment of five blood glucose meters. The instruments' analytical characteristics under optimum laboratory conditions and examination of potential sources of errors were intercompared. All glucometers produced precise results, and in all but one meter the CV values varied between 1.5% and 6%. CV's for reproducibility and within-day precision of Glucometer Gx were 10.5% and 7.3%. Sample volume, blood incubation time and colour stability of the strip may influence the results of blood glucose measurements with glucose meters. Underloading the sample strip had statistically significant effects on normal blood glucose values for all meters. One Touch II gave also significantly different results when the strip was overloaded. Incubation times shorter or longer than those recommended by the manufacturer influenced the results of all glucose meters. After colour development of the strip, changes were small for Haemo-Glukotest 20-800R strips and Glucotrix, whereas Accutrend glucose strips had to be read immediately following the prescribed incubation time. Comparison of the glucose meter results with those obtained by the hexokinase method showed good correlation coefficients for Reflolux S (r = 0.992), Accutrend (r = 0.988), One Touch II (r = 0.942), Glucometer Gx (r = 0.986) and Glucocard (r = 0.976). Error grid analysis showed that the results of all meters were clinically correct. Variations in haematocrit are known to be a source of errors when blood glucose is determined with a test strip. In the normoglycaemic range the results obtained with Accutrend and Glucocard were not influenced by even extreme haematocrit values. In the high glucose concentration range there was a decrease in blood glucose values with increasing haematocrit for all meters. This error was smaller with Accutrend and Glucocard than with the other meters. Although the new versions of the monitors are easier to use, their analytical performance is not superior to earlier models.

Blood Glucose Self-Monitoring↗
PubMed2004

Near-patient testing for infection using urinalysis and immuno-chromatography strips.

Urinary tract infections require costly confirmatory tests such as a urine culture to establish the diagnosis. Elimination of the culture step would save resources; diagnosis and treatment could begin in hours rather than days. We tested a new dip-and-read strip that uses immuno-chromatography (IC) to detect infectious agents in urine. We used a goat-derived polyclonal antibody with reactivity to the cell-wall proteins of Escherichia coli (E. coli). Fluorescein linked to the anti-E. coli antibody served to trap the bacteria on a strip coated with an anti-fluorescein mouse antibody. Blue latex particles were linked to anti-E. coli antibodies by standard methods and were used for detection of E. coli. We found that the combination of leukocyte esterase and nitrite dipsticks gave negative predictive values of 93% for culture-negative urines, i.e., there were very few false-negative results. Using the same dipsticks on culture-positive specimens, the positive predictive values were unacceptably low; we obtained too many false-positive values. By contrast, the IC strips gave negative predictive values of 89%. The major advantage of the IC strips is that the positive predictive values were higher, i.e., there were fewer false-positive results. The combined use of both IC strips and urinalysis dipsticks offers the best strategy for diagnosing infection with dipsticks. The IC strip test could reduce the necessity of a urine culture in patients with suspected infections and provide rapid point-of-care testing.

Antibody-Coated Bacteria Test, Urinary↗
PubMed2005

Development of a one-step strip test for the diagnosis of chicken infectious bursal disease.

A rapid diagnostic strip for chicken infectious bursal disease (IBD) was developed based on membrane chromatography using high-affinity monoclonal antibodies directed to chicken infectious bursal disease virus (IBDV). The diagnostic strip has high specificity for detection of chicken IBDV antigen and recognizes a variety of the virus isolates, including virulent and attenuated strains, with no cross-reactivity to other viruses, such as Newcastle disease virus, Marek's disease virus, infectious bronchitis virus, infectious laryngotracheitis virus, and egg-drop-syndrome virus. The results showed that its specificity was highly consistent with the agar-gel precipitation test (AGP). The diagnostic strip detected as low as 800 median egg lethal dose (ELD50) viruses in the IBDV BC6/85-infected sample, which was comparable with AC-ELISA (400 ELD50) and 32 times more sensitive than the AGP test (2.56 x 10(4) ELD50). In experimental infection, IBDV was detected in the bursa as early as 36 hr postinfection with the diagnostic strip before the clinical signs and gross lesions appeared. It takes only 1-2 min to do a strip test to detect chicken IBDV antigen after the specimen is grounded in a whirl pack with finger massage.

Animals↗
PubMedDate not supplied

Comparison of urine trypsinogen-2 test strip with serum lipase in the diagnosis of acute pancreatitis.

BACKGROUND/AIMS: The accuracy of a new rapid urinary trypsinogen-2 test strip (actim Pancreatitis) was compared with that of serum lipase for detection of acute pancreatitis in patients with acute abdominal pain. METHODOLOGY: A prospective study was conducted which consisted of 237 consecutive patients with acute abdominal pain admitted to the emergency unit at Helsinki University Central Hospital. The patients were tested on admission with the actim Pancreatitis test strip. Serum amylase, serum lipase, and urine trypsinogen-2 concentrations were also determined quantitatively. RESULTS: The actim Pancreatitis test strip result was positive in 27 out of 29 patients with acute pancreatitis (sensitivity 93%) and in 16 of 208 patients with non-pancreatic abdominal pain (specificity 92%). This was superior to that of serum lipase (sensitivity 79% and specificity 88%). With a cut-off > 3x the upper reference limit, the sensitivity of serum lipase was only 55% while the specificity was 99%. The high sensitivity for the actim Pancreatitis test strip resulted in a very high negative predictive value of 99%. All six patients with severe acute pancreatitis were detected by the dipstick. With a higher cut-off value (> 3x upper reference limit) for lipase, two patients with severe acute pancreatitis remained undetected. Combining the actim Pancreatitis dipstick with serum lipase a positive predictive value of 94% was obtained. CONCLUSIONS: Acute pancreatitis can be excluded with a higher probability with the actim Pancreatitis strip than with serum lipase determination, and therefore appears to be more suitable for screening of acute pancreatitis. With its high specificity with a cut-off > 3x the upper reference limit, serum lipase is suitable as a confirmatory test for pancreatitis when a positive dipstick result is obtained.

Abdominal Pain↗
PubMed1994

The recovery efficiency of various materials for sampling enzymes and polymorphonuclear leukocytes from gingival crevices.

The present investigation was designed to assess the effects of strips made of different materials on the recovery of enzymes in gingival crevicular fluid (GCF) (Experiment 1), and to examine a possible relationship between lysosomal enzyme activities and number of crevicular polymorphonuclear leukocytes (PMNs) (Experiment 2). In Experiment 1, GCF was collected with capillaries from 14 patients with periodontal disease, and applied on various test strips in microcentrifuged tubes or directly into tubes (controls). Strips were then shaken and centrifuged to elute GCF enzymes. The supernate was used for determinations of alkaline phosphatase (ALP), beta-glucuronidase (BG) and aspartate aminotransferase (AST) activities. The % recoveries were calculated as relative percentages to controls. When using saline as eluent, 90% or more ALP, BG and AST were found to be recovered from strips of durapore and papers. More than 35% of ALP and BG was found to remain on paper points. However, the % recoveries from paper points were improved using eluent with 0.1% (w/v) cetyl pyridinium chloride. In Experiment 2, 54 GCF samples were collected from 3 periodontitis patients by using durapore strips, in order to measure both PMN numbers and BG activities in the same samples. The 2 parameters showed strong and positive correlation with 0.847 (p < 0.001) of the Pearson's correlation coefficient. These findings suggest that durapore is a useful material not only for counting PMNs but also for measuring activities of GCF enzymes. Elevation of BG activities in GCF can be due to increasing numbers of PMNs.

Alkaline Phosphatase↗
PubMed1999

[Micromethod for the identification of streptococcal, enterococcal and staphylococcal species].

The aim of this study was to set accurate and reliable methods in the identification of streptococcal, enterococcal and staphylococcal species. Micro CSB Strep and Staph system consists each of a strip with cupules containing dehydrated substrates for biochemical identification of bacterial species. Baye's theorem was used to validate tests. Reactions from micromethods were clear and easily read. Identification of 229 strains of streptococci and enterococci was correct for most species with 98.7% species with 99.3% sensitivity. 41 strains of staphylococci were also correctly identified with 85.2% of specificity and 97.68% of sensitivity.

Bacterial Typing Techniques↗
PubMed1975

[Self-testing of urine in insulin treatment (author's transl)].

The self-testing of urine has proved outstanding for the optimal adjustment and supervision of insulin treatment. Among the tests for determination of sugar in the urine, the Clinitest method is preferred to the enzymatic test strip method. The various possibilities for use of the self-testing of urine are shown in a 4-stage scheme. They are determined by the object of therapy and the capacity of the diabetic to co-operate. Self-testing of urine serves the following purposes: 1. prophylaxis of coma, 2. encouragement of dietary discipline, 3. a guide for the doctor, 4. self-adaptation of the insulin dosage.

Adult↗
PubMed1993

One-step competitive immunochromatographic assay for semiquantitative determination of lipoprotein(a) in plasma.

Numerous studies have associated high concentrations of lipoprotein(a) [Lp(a)] with atherosclerosis. We developed a rapid, one-step competitive immunochromatographic assay to measure Lp(a) in plasma. The assay is performed on a nitrocellulose membrane strip and the result is determined by a visual readout of rust-colored colloidal selenium. The assay is based on the principle that Lp(a) in the sample will compete with Lp(a)-coated colloidal selenium for binding to the anti-Lp(a) monoclonal antibody immobilized on the assay strip in the format of four ladder bars. The number of capture bars that appear as a result of the formation of colloidal selenium color is proportional to the concentration of the Lp(a) protein in the samples. The strip assay semiquantitatively measures Lp(a) concentrations ranging from 0 to 180 mg/L of Lp(a) protein in serum, plasma, or fingerstick whole-blood samples. This assay appears very useful for quick identification of individuals with above-normal concentrations of plasma Lp(a) protein (> 70 mg/L), and has potential for monitoring a patient's response to treatment with Lp(a)-lowering drugs.

Animals↗
PubMed1990

[A tear strip test in the control of contact lens wearers].

A series of 86 contact lens wearers has been examined by tear-stix tests (35 wearing hard lenses and 51 soft). Of these, 52 showed no infection (group A), while 34 had signs and/or symptoms of infection (group B). Leucocyte-esterase positivity was seen in 8% of group A and 62% of group B. Stix-positive were 13% of group A and 85% of group B (positive leucocyte-esterase and/or positive nitrite and/or positive hemoglobin). The examinations are quick and easy to carry out, with a reasonable sensitivity and specificity.

Clinical Enzyme Tests↗
PubMed1988

Evaluation of a new Seralyzer assay for carbamazepine.

The performance of a new dry-phase, strip immunoassay technique for the analysis of serum carbamazepine concentrations (Seralyzer), was compared to a standard high performance liquid chromatography (HPLC) method. One hundred blood samples were collected from 87 patients and analysed using both techniques. There was no significant difference between the concentrations measured by either technique, and the results were highly correlated (r = 0.97). The Seralyzer is a rapid and accurate method for use in carbamazepine therapeutic drug monitoring.

Carbamazepine↗
PubMed2004

Rapid detection of mutations in Wilson disease gene ATP7B by DNA strip technology.

Wilson disease leads to severe hepatic and neurological pathology resulting from cellular copper overload in the respective tissue. Although the affected gene, ATP7B, has been identified, genetic testing is challenging, time-consuming and expensive. Here we describe the development and use of a novel diagnostic test for four frequent mutations (M769V, W779X, H1069Q and P1134P-fs) found in Germany and many other countries in Europe. The test is based on multiplex polymerase chain reaction and DNA strip technology and was found to be highly sensitive and specific, as well as timely and cost-effective. We conclude that this test is a useful and reliable tool to screen Wilson disease patients and their family members for these mutations and may facilitate diagnosis in this complex disease.

Adenosine Triphosphatases↗
PubMed1989

The use of cephalothin and triphenyltetrazolium chloride impregnated filter paper strips in the identification of Campylobacter species.

Filter paper impregnated strips using cephalothin at 30 and 60 micrograms/ml and triphenyltetrazolium chloride at 20 mg/ml were prepared and used in the typing of catalase-positive Campylobacter species. There was no difference in the sensitivity of campylobacters to cephalothin at 30 micrograms/ml and 60 micrograms/ml. Results were as reported by other workers except for a C. jejuni strain which was resistant to the triphenyltetrazolium. The technique is nevertheless inexpensive and the results are consistent and easy to interpret.

Animals↗
PubMed1997

Problems in the assessment of glycaemic control in diabetes mellitus.

The measurement of glycated haemoglobin and serum fructosamine to assess the recent glycaemic control of diabetic patients has become well established. Likewise, the monitoring of blood glucose using glucose test strips and meters has become popular in both the community and in the hospital inpatient environment. However, despite improvements in the methods of analysis, clinically inaccurate assessments of glycaemia can still occur. Specific problems such as the lack of standardization in assays are in the process of being resolved, but inherent difficulties associated with these measures remain. Clinicians should be aware that these tests still need to be interpreted in conjunction with clinical prudence.

Aging↗