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PubMed2004

High-performance anion-exchange chromatography coupled with pulsed amperometric detection and capillary zone electrophoresis with indirect ultra violet detection as powerful tools to evaluate prebiotic properties of fructooligosaccharides and inulin.

Fructooligosaccharides (FOS) and inulin are food grade non-digestible carbohydrates that exert beneficial nutritional effect. This paper describes the suitability of high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) and capillary zone electrophoresis (CZE) to evaluate fermentation properties of FOS and inulin in pure Bifidobacterium cultures; and to study their effects on faecal cultures (microbial population and short-chain fatty acids). Prebiotic effectiveness of FOS and inulin of different degrees of polymerization was evaluated monitoring the changes in their molecular weight distribution during the in vitro growth of selected Bifidobacterium strains. The qualitative analysis of the residual soluble oligosaccharides or polysaccharides from Raftilose Synergy, Raftiline HP and Raftilose P95 was carried out by HPAEC-PAD, using a CarboPac PA 100 column and an appositely optimized gradient elution program. Under the optimized gradient elution conditions, glucose, fructose, sucrose were resolved from each other and from fructans with a DP ranging from 3 (1-kestose) to 60. The chromatographic profiles of the spent broths pointed out that almost every strain presented a different capability to ferment fructan chains of variable DP, indicating wide strain to strain differences. To explore the prebiotic effect of FOS and inulin, related to of short chain fatty acids (SCFAs) accumulation in faecal cultures due to fermentative metabolism of intestinal microflora, analysis of SCFAs, acetic and lactic acid was achieved by co-electroosmotic capillary electrophoresis, where the electrophoretic mobility of the anionic analytes and electroosmotic flow (EOF) were similarly directed. Moreover, the use of UV detection for the analyses of our organic anions required a running electrolyte which allowed indirect detection. The optimization of the capillary electrophoretic conditions was carried out by applying a chemometric study based on the use of the experimental design, the effects of three parameters, i.e. temperature, voltage and percentage of methanol added to the background electrolyte were investigated.

Anion Exchange Resins↗

PubMedDate not supplied

[Comparative results of total detections and detection in a group of patients with high risk for tuberculosis in an urban environment].

In the territory of 5 anti-TBC dispensaries in the area of Bucharest 2 circumscriptions have been selected at random in which radiophotographic detection was to be carried out integrally and 2 other circumscriptions were selected for the investigation of groups at high risk of developing tuberculosis. All the new cases of active pulmonary tuberculosis that have been recorded, through all the methods in these 20 circumscriptions in 1973 were analized retrospectively and the reasons appeared that had determined their existence was mentioned or was ommitted on the occasion of previous investigations. These reasons were correlated with the data concerning the method for detection that had been employed, according to the indications of the tuberculosis dispensaries. In view of the evaluation of the degree of real covering of the population in integral rf investigations, the team of the Institute of Phtysiology investigated representative lots of population from each dispensary and checked the catagraphy of the population in the field, house-by-house. It was noted that 20--21% of the subjects that had been programmed for the integral rf examination (according to catagraphic criteria) were absent when the checking in the field, that should have been programmed, were not included in the catagraphy. On the basis of this study the methodology for radiophotographic detection for groups with risk of developing tuberculosis was established.

Humans↗

PubMed1991

Emergency toxicology testing (detection, confirmation, and quantification) of basic drugs in serum by liquid chromatography with photodiode array detection.

We investigated the applicability of liquid chromatography with photodiode array detection as a serum drug screening technique in an emergency toxicology setting. Basic compounds are extracted from alkalinized serum with hexane and chromatographed on a cyanopropyl reversed-phase column. The photodiode array detector records the ultraviolet spectrum of each eluting peak for identification and quantification. More than 30 drugs/metabolites including antidepressants, antihistamines, phenothiazines, and analgesics are detected at their therapeutic concentrations or less. Quantitative run-to-run precision (CV) for antidepressant drugs at low therapeutic concentrations is less than 6%. We evaluated the potential for interference of greater than 140 compounds of clinical interest. In a split-sample study, 151 of 154 positive drug findings by the method were confirmed by alternative techniques (gas chromatography/mass spectrometry and liquid chromatography with either normal-phase or reversed-phase columns). In the three unconfirmed findings, this method detected drugs at concentrations below the limit of identification of the comparison method. Also, 275 samples judged negative by this procedure were negative by a different liquid-chromatographic method.

Analgesics↗

PubMed1991

Separation and detection of DNA polynucleotides using capillary electrophoresis. Application to detection of polymerase chain reaction-amplified human immunodeficiency virus and HLA DNA.

The polymerase chain reaction (PCR) is a technique for rapid amplification of target DNA sequences. During the past several years, a large number of research applications of PCR have appeared, many of which may prove to be useful clinically. We report the use of capillary electrophoresis, a fully automated technique, as an alternative to polyacrylamide gel electrophoresis for the detection of PCR-amplified viral and cellular DNA. We describe conditions for rapid separation, detection, and discrimination of PCR products from the human immunodeficiency virus type 1 gag gene and the HLA-DQ-alpha gene amplified from the human immunodeficiency virus provirus-containing U1.1 cell line. The sensitivity achieved with the use of capillary electrophoresis analysis was roughly equivalent to that of ethidium bromide staining of polyacrylamide gel electrophoresis gels. Further refinement of capillary electrophoresis for automated detection and quantitation of PCR-amplified products should expedite more widespread application of PCR analysis in the clinical laboratory.

DNA↗

PubMed1989

The application of a photon-counting camera in sensitive, bioluminescence-enhanced detection systems for nucleic acid hybridization. Ultrasensitive detection systems for protein blotting and DNA hybridization, III.

A relatively simple, bioluminescence-enhanced detection system for nucleic acid hybridization, using alkaline phosphatase as a label, was described recently (Hauber, R. & Geiger, R. (1988) Nucl. Acid Res. 16, 1213). The principle of detection is as follows: Alkaline phosphatase releases D-luciferin (Photinus pyralis) from D-luciferin-O-phosphate. Liberated D-luciferin reacts with luciferase, ATP and oxygen with light emission. Light produced is measured with a very sensitive photon counting camera system (Argus-100), allowing the visualization and localization of the specifically bound alkaline phosphatase on nitrocellulose sheets. Under non-optimized conditions the limit of detection is at present about 30 pg of pBR322. A sulphonylated nucleotide probe was used for hybridization.

Alkaline Phosphatase↗

PubMed1988

Immunoassay detection of drugs in racing horses. IV. Detection of fentanyl and its congeners in equine blood and urine by a one step ELISA assay.

We have developed and evaluated a one step enzyme-linked immunosorbent assay (ELISA) test for fentanyl as part of a panel of pre- and post-race tests for narcotic analgesics in racing horses. This ELISA test detects fentanyl with an I-50 of about 100 pg/ml. The test is economical in that it can be read with an inexpensive spectrophotometer, or even by eye. The test is rapid, and ten samples, a normal pre-race complement, can be analyzed in about twenty minutes. The test readily detects the presence of fentanyl or its metabolites in equine blood and urine from two and twenty-four hours respectively after administration of sub-therapeutic doses. The two antibodies evaluated also cross-react with the methylated analogs of fentanyl, sufetanil and carfentanil and the test detected these drugs shortly after their administration to horses. When introduced into routine screening, this test, in combination with another immunoassay test previously described, yielded 10 sufentanil positives. As such this test is capable of both improving the quality and reducing the cost of pre-race and post-race testing for fentanyl and a number of its congeners in racing horses.

Analgesics↗

PubMed1987

[Immunologic methods for the detection of diphtheria toxin (passive hemagglutination and ELISA for toxin detection in cultures and serum)].

A competitive passive hemagglutination assay (cPHA) easy to perform and a highly sensitive ELISA have been investigated for detection of diphtheria toxin from cultures and from human serum. The sensitivity of the cPHA (8 ng toxin/ml) was high enough to detect toxin in pure cultures containing C. diphtheriae. For this application the cPHA proved to be a simple and reproducible alternative to the Elek-Ouchterlony test. Toxin in culture filtrates of nasal and tonsillar swabs containing toxinogenic strains of C. diphtheriae together with germs of the physiological flora and toxin in serum can be detected with the more sensitive Biotin/Streptavidin ELISA (0.6 ng toxin/ml). This allows the confirmation of the clinical diagnosis "diphtheria" within 24-48 h.

Animals↗

PubMed1988

Immunoassay detection of drugs in racing horses. III. Detection of morphine in equine blood and urine by a one step ELISA assay.

A one step enzyme-linked immunosorbent assay (ELISA) test for morphine was evaluated as part of a panel of pre- and post-race tests for narcotic analgesics in racing horses. This ELISA test is very sensitive to morphine with an I-50 for morphine of about 400 pg/ml. The test is also rapid, and ten samples, a normal pre-race complement, can be analyzed in about thirty minutes. The test can be read with an inexpensive spectrophotometer, or even by eye. The test readily detects the presence of morphine or its metabolites in equine blood for up to six hours after administration of sub-therapeutic doses. The antibody also cross-reacts with hydromorphone, orymorphone, nalorphine, levorphanol, and codeine, and the test either can detect or is likely to detect these drugs in blood or urine shortly after their administration to horses. As such this test is capable of dramatically improving the speed and efficacy of both pre-race and post-race testing for morphine and its congeners in racing horses. On initial introduction into post-race urine screening this test flagged 18 of 166 samples positive for opiates, and 13 of these samples were confirmed positive for opiates by mass spectrometry.

Animals↗

PubMed1986

Detecting linkage for genetically heterogeneous diseases and detecting heterogeneity with linkage data.

Interest in searching for genetic linkage between diseases and marker loci has been greatly increased by the recent introduction of DNA polymorphisms. However, even for the most well-behaved Mendelian disorders, those with clear-cut mode of inheritance, complete penetrance, and no phenocopies, genetic heterogeneity may exist; that is, in the population there may be more than one locus that can determine the disease, and these loci may not be linked. In such cases, two questions arise: (1) What sample size is necessary to detect linkage for a genetically heterogeneous disease? (2) What sample size is necessary to detect heterogeneity given linkage between a disease and a marker locus? We have answered these questions for the most important types of matings under specified conditions: linkage phase known or unknown, number of alleles involved in the cross at the marker locus, and different numbers of affected and unaffected children. In general, the presence of heterogeneity increases the recombination value at which lod scores peak, by an amount that increases with the degree of heterogeneity. There is a corresponding increase in the number of families necessary to establish linkage. For the specific case of backcrosses between disease and marker loci with two alleles, linkage can be detected at recombination fractions up to 20% with reasonable numbers of families, even if only half the families carry the disease locus linked to the marker. The task is easier if more than two informative children are available or if phase is known. For recessive diseases, highly polymorphic markers with four different alleles in the parents greatly reduce the number of families required.

Alleles↗

PubMed1987

Comparison of auditory-evoked potential detection methods using signal detection theory.

The performance of statistical evoked-potential detection methods was compared with that of human observers and among themselves by means of receiver operating characteristics (ROC) curves. The test material was a collection of brain stem auditory-evoked responses obtained from 98 infants with 60 and 30 dB nHL clicks. The observers and the statistical methods had to discriminate these responses from control recordings obtained without acoustic stimulation. Although the observers' criteria on different days varied considerably, the discrimination capacity was more stable. The discrimination capacity depended on the observers' experience. The statistical methods tested were the correlation coefficient (CCR), the standard deviation ratio (SDR) and a new method named T2R. The most efficient detection method was T2R. For false-alarm rates of 0.01 the statistical methods were more efficient than the human observers. Signal detection theory is useful for the evaluation of evoked-potential analysis methods.

Brain Stem↗

PubMed1982

A system for preparation, detection and identification of a precipitinogen (eta) of strains of Mycobacterium tuberculosis, that is not detectable in strains of M. bovis.

A precipitinogen (designated eta: eta), which was undetectable in BCG and the Ravenal strain of Mycobacterium bovis, was detected in sonic extracts of the H37Rv and H37Ra strains of M. tuberculosis by agar gel immunodiffusion. Since precipitinogen eta was very labile in cell extracts and crude preparations, reproducible methods for preparing and detecting the precipitinogen eta were investigated. Two conditions were found necessary for a stable preparation: (1) deferration of all materials to which eta precipitinogen was exposed throughout procedures and (2) use of phosphate buffer of over pH 7.5 and over 0.07 M for solubilizing eta. Two methods were effective and useful for purification of precipitinogen eta: (1) Salting-out using deferrated ammonium sulfate (35-40% saturation) and (2) gel permeation chromatography on Sephadex G-200 or Bio-gel P-300 that had been thoroughly washed with chelating agents. The purified eta prepared by a combination of these two methods, retained activity on storage in the frozen state for several years or on incubation at 40 C for 30 min. A system was developed for detection and identification of eta using stable, purified eta as a reference. eta Precipitinogen was heat-labile (60 C for 10 min), and behaved as an acidic protein with a molecular weight of 230,000 or approximately 260,000 daltons.

Antigens, Bacterial↗

PubMed1993

Detection of antiphospholipid antibodies by flow cytometry: rapid detection of antibody isotype and phospholipid specificity.

Laboratory diagnosis of antiphospholipid antibodies is important in patients with clinical features of the antiphospholipid syndrome, such as thrombosis and fetal loss. We have developed a novel method for the detection of antiphospholipid antibodies using flow cytometry. Anionic phospholipids cardiolipin, phosphatidylserine and phosphatidylinositol are coated onto polystyrene beads of different sizes, allowing detection and semiquantitation of their respective phospholipid antibody isotypes. The results of the flow cytometric method closely correlate those of the standardised anticardiolipin enzyme-linked immunosorbent assay (ELISA), but the method is quicker and is versatile in its ability to detect IgG, IgM and IgA antibody isotypes at the same time. The method promises to be useful in evaluating the significance of phospholipid specificity and antibody isotypes in patients with the antiphospholipid syndrome.

Antibodies, Antiphospholipid↗

PubMed1994

Detection of occult gastrinomas with iodine 125-labeled lanreotide and intraoperative gamma detection.

BACKGROUND: Surgical exploration for gastrinoma has a high failure rate because of small primary tumors and occult metastasis. Despite extensive preoperative and intraoperative tumor localization, only 30% to 40% of patients with gastrinoma are cured by surgery. Two patients with unlocalized gastrinomas were studied with intraoperative gamma detection of an iodine 125-labeled somatostatin analog, lanreotide, to localize their tumors. METHODS: Both patients were challenged before operation with 100 micrograms of octreotide acetate, and both had circulating gastrin levels suppressed by greater than 50%. Iodine 125-labeled lanreotide (100 to 150 muCi) was injected during exploration, and an intraoperative gamma detector was used to detect tumor binding of the analog. RESULTS: In patient 1 a single source of increased counts was discovered in a retroduodenal lymph node, which was excised; no other tissue was removed. Histologic study of this node failed to demonstrate tumor; however, the patient's gastrin level was normal (63 pg/ml) 4 months after operation. In patient 2 five areas of increased counts were discovered and excised. Three of these five areas had visible tumor on microscopic examination. Three months after operation the patient's fasting gastrin level was 103 pg/ml. CONCLUSIONS: Intraoperative gamma detection of radiolabeled peptides may allow the localization of occult tumors that contain specific peptide receptors.

Adult↗

PubMed1994

[Effectiveness of hypercholesterolemia detection in high risk individuals compared to opportunistic detection].

BACKGROUND: The aims of this study were to estimate the number of people who should receive some intervention (pharmacologic and/or dietetic) to reduce cholesterol concentrations and to evaluate selective case finding in comparison to opportunistic detection. METHODS: Six hundred twenty-five individuals participating in a study of cardiovascular risk factors were included in the study. Those with total cholesterol concentrations (TC) greater than 6.2 mmol/l and those with CT concentrations greater than 5.2 mmol/l observed upon lipid profile analysis and history of cardiovascular disease and/or risk factors were considered as candidates. Out of these individuals, those with cholesterol concentrations linked to low density lipoproteins greater than 4.14 mmol/l or greater than 3.37 mmol/l and previous history of cardiovascular disease or two risk factors were considered candidates to undergo intervention to reduce cholesterol concentrations. Moreover, the number of individuals with CT concentrations greater than 6.2 mmol/l which would not be detected if CT was only determined in those who already had another cardiovascular risk factor was estimated. RESULTS: 37.5% (CI 95%; 33.8%-41.5%) of the individuals required lipid profile and out of these 88.8% (CI 95%; 3.8%-92.4%) were candidates to receive intervention. Upon evaluating the efficacy of the strategy of selective case finding it was observed that the sensitivities of the risk factors were low, ranging from 22.6% in those with family history of cardiovascular disease to 34.8% in cases with personal history of high blood pressure. CONCLUSIONS: If selective case finding of high risk subjects was the only strategy applied, many individuals with hypercholesterolemia would remain undetected, therefore the strategy of opportunistic detection is preferable whenever possible.

Adult↗

PubMed1997

Novel detection system of flow injection analysis (1). The existence of significant relation between secondary structure of DNA and sensitivity in signal detection.

Polymerase Chain Reaction (PCR) products was detected quantitatively using a flow injection type sensor, based on Surface Plasmon Resonance (SPR). We used asymmetric PCR to amplify the two kinds of products; their DNA lengths are different. This novel design permitted us not only to detect PCR products with high-sensitivity, but also to develop a rapid DNA detection system for the sense of the genetic pathogen.

Bacterial Toxins↗

PubMed1997

Novel DNA detection system of flow injection analysis (2). The distinctive properties of a novel system employing PNA (peptide nucleic acid) as a probe for specific DNA detection.

In order to realize immediate detection of a double stranded DNA amplified by Polymerase Chain Reaction (PCR), we applied Peptide Nucleic Acid (PNA) to the probe of DNA detection system using Surface Plasmon Resonance (SPR). We report our success in immediate detection of PCR products solution with high sequence-specificity.

Bacterial Toxins↗

PubMed1998

Fixed polarizer ellipsometry for simple and sensitive detection of thin films generated by specific molecular interactions: applications in immunoassays and DNA sequence detection.

Biological thin films may form on a surface by specific molecular interactions. The fixed polarizer ellipsometer (FPE) is a sensitive instrument that detects biological thin films either qualitatively or quantitatively. The design is simple and inexpensive. The assays are formatted on an optical surface, and the FPE detection is based on the phase shift of linearly polarized light after reflection through a thin film. We have constructed mathematical models of the FPE response to reflection through single-layer and two-layer films that agree closely with experimental data. Several biological assays have been measured with the FPE to demonstrate the application of this technology to clinical targets, including ultrasensitive immunoassays for hepatitis B surface antigen (0.1 ng/mL) and alpha-fetoprotein (0.01 ng/ mL) and DNA hybridization (0.5 fmol/microL target probe). A clinical study for detection of group A streptococcus from patient throat swabs demonstrated the qualitative application of the FPE to infectious disease targets. The flexibility and sensitivity of the FPE makes this technology suitable for numerous target analytes and applications.

Antigens, Bacterial↗

PubMed1998

[Comparison of three fat suppression sequences for the detection of vertebral detection. Turbo STIR, phase contrast gradient-echo, and MISTEC-Chopper after gadolinium injection].

OBJECTIVES: Assess three fat suppression sequences used to search for spinal metastases: TurboSTIR, phase contrast gradient-echo, and MISTEC-Chopper after gadolinium injection. MATERIAL AND METHODS: A prospective study was conducted in 10 patients with primary neoplasia. MIR sequences acquired (1 Tesla) were TurboSTIR, T1 spin-echo with and without gadolinium injection, phase contrast gradient-echo and M-Chop after gadolinium injection. Signal intensity in normal bone marrow, metastatic tissue, and subcutaneous fat as well as background noise was measured. Signal-to-noise (S/N) ratio was determined. Lesion borders, artefacts, and extent of detected lesions were determined quantitatively. Bone marrow signal intensity was also recorded. RESULTS: S/N ratio was best with gradient-echo which identified well the borders of lesions within the hemopoietic marrow. For lesions located in high-fat marrow (as in post-radiation marrow), the high intensity signal of the lesion confounded with the fat signal. TurboSTIR gave effective fat signal suppression and was particularly useful for yellow marrow, less so for red marrow. This technique confounded cell proliferation with perilesional edema (enlarging lesion extention). In one case, this sequence did not detect a small lesion visible with the two other sequences. This sequence was sensitive to artefacts (especially vascular artefacts) which can produce false nodular images. M-Chop gave good suppression of vertebral fat tissue (better for yellow marrow) but subjective detection of lesions was more difficult. CONCLUSION: The phase contrast gradient-echo sequence after gadlinium injection appeared to be the best sequence excepting cases of post-trauma (radiotherapy or chemotherapy) fat transformation of the marrow where the TurboSTIR sequence could be preferred.

Adipose Tissue↗