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Biomedical subjects

B B Lentrichia

Publications and source records attributed to B B Lentrichia.

8 recordsLinked to original sources
PubMed2001

Chlamydia trachomatis and Pap testing from a single, fluid-based sample. A multicenter study.

OBJECTIVE: To determine the potential for both Pap testing and the Chlamydia direct fluorescence assay (DFA) from a single sample using the fluid-based ThinPrep Pap Test method (Cytyc Corporation, Boxborough, Massachusetts). STUDY DESIGN: Conventional DFA was compared to ThinPrep DFA in a direct-to-vial, double-blinded, multicenter protocol. Cervical scrapings were collected for the ThinPrep Pap Test, and then a second swab was used to collect an endocervical sample for a conventional DFA test. The DFA slide prepared from the ThinPrep Test and the conventional DFA sample prepared from the endocervical swab were evaluated independently. Discrepant cases were adjudicated by testing residual specimens using a Chlamydia direct DNA method. RESULTS: Combining 636 adequate cases (94% of the total collected), 582 (91.5%) were negative on both slides, 43 (6.8%) positive by both and 11 (1.7%) discrepant. The prevalence of Chlamydia was 7.9% based on the conventional DFA method (range, 4.3-10.9%). McNemar's two-tailed test indicated the results not to be statistically different (P > .05). Adjudication favored ThinPrep 45% of the time and conventional 55%. Specimen adequacy favored ThinPrep with high statistical significance (McNemar's test, P > .01). CONCLUSION: A second slide prepared from the same vial of cells as that used for the ThinPrep Pap Test can be used for Chlamydia testing by DFA. Fluid-based collection could allow multiple tests from a single sample.

Adolescent↗
PubMed1988

Biogenesis and content of rhodopsin in the retina of the chick during development.

Developmental aspects of the formation of rhodopsin in the chick were investigated. The content of rhodopsin was measured in the retina of the developing chick embryo, newly hatched and adult chickens by both spectral and immunological procedures. Rhodopsin was first detected spectrally at day 18 (stage 43) with the level increasing about 6 fold through hatching. The concentration in the adult retina was about one half that present in the 1 day old chick. By the more sensitive procedure of radioimmunoassay (RIA), rhodopsin was detected as early as day 12 (stage 37), but was undetectable in the 8 day old embryo. The rhodopsin concentration remained low and relatively constant until day 17 (stage 42), at which point it increased rapidly up to hatching. Retina from the newly-hatched chick had a rhodopsin concentration some 30 fold higher than the 16 day old embryo (stage 41). The results of RIA indicate that the biosynthesis of rhodopsin may significantly precede the morphological appearance of outer segments.

Animals↗
PubMed1987

The influence of carbohydrates on the binding of rod outer-segment (ROS) disc membranes and intact ROS by the cells of the retinal pigment epithelium of the embryonic chick.

The role of carbohydrates in mediating the interaction of rhodopsin-containing membranes with retinal pigment epithelium (RPE) cells was investigated by studying the influence of various monosaccharides on their binding by RPE cells of the embryonic chick maintained in cell culture. Rod outer-segment (ROS) disc membranes were selected as a model rhodopsin-containing membrane system for these studies in view of their high concentration of rhodopsin and the relative purity with which they can be isolated. Disc membranes, frozen and thawed in order to expose the carbohydrate groups of rhodopsin which are oriented intraluminally in situ, were incubated with monolayers of RPE cells under various conditions, and the binding of the membranes by the cells was quantitated by radioimmunoassay for rhodopsin. Cell-membrane association was also verified by indirect immunofluorescence microscopy. The surface accessibility of the sugars in frozen-thawed discs was verified by succinyl concanavalin A-binding studies. From 15- to 20-fold increase in carbohydrate-reactive sites was obtained after freezing and thawing the discs. The RPE cell-membrane binding process was saturable, and time- and temperature-dependent. By means of competition studies carried out in the presence of high concentrations of various monosaccharides, and also by comparing the binding of disc membranes whose carbohydrate groups were either exposed (frozen-thawed) on the surface or inaccessible (native), it was concluded that the carbohydrates of rhodopsin, mannose and N-acetylglucosamine, were not involved in the interaction with the RPE. The possibility was also examined that enzymatically galactosylated rhodopsin might serve as a site for recognition by the RPE cell. The binding of ROS disc membranes modified in this manner was not enhanced, indicating that the presence of galactose groups on rhodopsin did not serve as a site for recognition by the RPE. The influence of monosaccharides on the binding of intact ROS by the RPE cells was also investigated. Similar to the results with the disc membranes, the process was not blocked by the presence in the incubation medium of high concentrations (up to 30,000-fold higher than that of rhodopsin) of mannose or GlcNAc, as with the disc membranes, or by glucose or galactose. Thus, from these studies it is concluded that a lectin-like carbohydrate-recognition process may not be involved in the interaction between rhodopsin-containing membranes and the RPE cells.

Animals↗
PubMed1987

Immunoassay of digoxin by differential centrifugation.

We describe an immunoassay of digoxin that exploits the differential sedimentation rate between two types of latex particles in a microcentrifugal analyzer. Conventional polystyrene latex particles (relative density = 1.05), sensitized with antibody, are first suspended with the sample and then mixed with digoxin-sensitized latex particles (relative density = 1.5). In the absence of digoxin in the sample, the two particle types bind to each other and, when subjected to centrifugal force, are cleared from the solution simultaneously. In the presence of digoxin, the binding between the particles is inhibited in proportion to the concentration of the drugs; the particles therefore can be differentially sedimented in 1 min. We measured the resulting absorbance to quantify the number of less-heavy particles and used the assay to generate a linear standard curve from 0 to 5 micrograms/L. Because the detection limit of the assay depends on the concentrations of both particle types, we optimized the assay by using two-dimensional analysis. Interference from rheumatoid factor was negligible up to 800 kilo-int. units/L. Precision studies indicated CVs between 5% and 13% within-run and between 4% and 9% for run-to-run in this endpoint assay.

Antibodies↗
PubMed1986

A sensitive kinetic latex agglutination immunoassay adapted to centrifugal analysis.

Latex reagents for HCG obtained from commercially available pregnancy test kits were adapted for use on Instrumentation Laboratory's Multistat III Plus centrifugal analyzer. The clearance rate of an agglutinating reaction mixture can be measured by absorbance over a time period of 15 min. The automated system has a sensitivity of less than 5 mIU HCG/ml in buffer or urine with a range of up to 100 mIU HCG/ml. Statistical analyses on urine samples indicated CVs of between 7.6% and 10.7% for within-run precision and between 6.8% and 10.8% for between-run precision. The correlation between the centrifugal latex agglutination method and two commercially available RIAs was found to be about 87%.

Antibodies↗
PubMed1978

Glycosidases of the retinal pigment epithelium.

The pH optima and apparent Km and Vmax values were determined for nine glycosidases of the retinal pigment epithelium (RPE) of the calf. In terms of micromoles of substrate cleaved per milligram protein per hour, the following relative order of enzymatic activities was observed: beta-N-acetylglucosaminidase greater than alpha-glucosidase = beta-N-acetylgalactosaminidase greater than alpha-mannosidase greater than beta-galactosidase greater than beta-glucosidase greater than alpha-fucosidase greater than alpha-galactosidase greater than beta-glucuronidase. The pH optimum of each of these enzymes was in the acidic range (below pH 6). All these findings refer to enzymatic activities of bovine RPE preparations obtained by the brushing procedure of Glocklin and Potts and washing as described by Berman and Feeney. Thus they may relate to those activities associated with particulate components of the RPE cell and not to the more soluble glycosidases. The distribution of the glycosidases between the washes of the cells and the final pellet of bovine RPE cells was examined. The activities of 10 glycosidases in the RPE of the embryonic chick were also examined. Neither beta-mannosidase nor beta-fucosidase activities could be detected in washed bovine RPE cells, although beta-mannosidase was detected in RPE of the embryonic chick. The presence of isoenzymes of beta-glucuronidase in bovine RPE was indicated. Specificity by beta-glucuronidase of bovine RPE for synthetic substrates was observed.

Acetylgalactosamine↗