scholarly journals Comparison of histomorphology and DNA preservation produced by fixatives in the veterinary diagnostic laboratory setting

2014 ◽  
Author(s):  
Michael J. Dark ◽  
William F. Craft ◽  
Julia A. Conway
Keyword(s):  
Dna Amplification ◽  
The Other ◽  
Formalin Fixation ◽  
Laboratory Setting ◽  
Diagnostic Laboratory ◽  
Dna Preservation ◽  
Diagnostic Practices ◽  
Morphologic Characteristics

Histopathology is the most useful tool for diagnosis of a number of diseases, especially cancer. To be effective, histopathology requires that tissues be fixed prior to processing. Formalin is currently the most common histologic fixative, offering many advantages: it is cheap, readily available, and pathologists are routinely trained to examine tissues fixed in formalin. However, formalin fixation substantially degrades tissue DNA, hindering subsequent use in diagnostics and research. We therefore evaluated three alternative fixatives, TissueTek® Xpress® Molecular Fixative, modified methacarn, and PAXgene®, all of which have been proposed as formalin alternatives, to determine their suitability for routine use in a veterinary diagnostic laboratory. This was accomplished by examining the histomorphology of sections produced from fixed tissues as well as the ability to amplify fragments from extracted DNA. Tissues were sampled from two dogs and four cats, fixed for 24-48 hours, and processed routinely. While all fixatives produced acceptable histomorphology, formalin had significantly better morphologic characteristics than the other three fixatives. Alternative fixatives generally had better DNA amplification than formalin, although results varied somewhat depending on the tissue examined. While no fixative is yet ready to replace formalin, the alternative fixatives examined may be useful as adjuncts to formalin in diagnostic practices.

scholarly journals Comparison of histomorphology and DNA preservation produced by fixatives in the veterinary diagnostic laboratory setting

2014 ◽  
Author(s):  
Michael J. Dark ◽  
William F. Craft ◽  
Julia A. Conway
Keyword(s):  
Dna Amplification ◽  
The Other ◽  
Formalin Fixation ◽  
Laboratory Setting ◽  
Diagnostic Laboratory ◽  
Dna Preservation ◽  
Diagnostic Practices ◽  
Morphologic Characteristics

Histopathology is the most useful tool for diagnosis of a number of diseases, especially cancer. To be effective, histopathology requires that tissues be fixed prior to processing. Formalin is currently the most common histologic fixative, offering many advantages: it is cheap, readily available, and pathologists are routinely trained to examine tissues fixed in formalin. However, formalin fixation substantially degrades tissue DNA, hindering subsequent use in diagnostics and research. We therefore evaluated three alternative fixatives, TissueTek® Xpress® Molecular Fixative, modified methacarn, and PAXgene®, all of which have been proposed as formalin alternatives, to determine their suitability for routine use in a veterinary diagnostic laboratory. This was accomplished by examining the histomorphology of sections produced from fixed tissues as well as the ability to amplify fragments from extracted DNA. Tissues were sampled from two dogs and four cats, fixed for 24-48 hours, and processed routinely. While all fixatives produced acceptable histomorphology, formalin had significantly better morphologic characteristics than the other three fixatives. Alternative fixatives generally had better DNA amplification than formalin, although results varied somewhat depending on the tissue examined. While no fixative is yet ready to replace formalin, the alternative fixatives examined may be useful as adjuncts to formalin in diagnostic practices.

scholarly journals Effects of Formalin Fixation, Paraffin Embedding, and Time of Storage on DNA Preservation in Brain Tissue: A BrainNet Europe Study

2007 ◽  
Vol 17 (3) ◽  
pp. 297-303 ◽  
Author(s):  
Isidre Ferrer ◽  
Judith Armstrong ◽  
Sabina Capellari ◽  
Piero Parchi ◽  
Thomas Arzberger ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Formalin Fixation ◽  
Dna Preservation ◽  
Paraffin Embedding

Air Travel and Contact Lenses: A Laboratory Study

1988 ◽  
Vol 32 (6) ◽  
pp. 450-454
Author(s):  
Joseph E. Laviana ◽  
Frederick H. Rohles
Keyword(s):  
Relative Humidity ◽  
Contact Lenses ◽  
Flight Time ◽  
Air Travel ◽  
The Other ◽  
Laboratory Setting ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Significant Difference ◽  
The Impact

The cabin of an inflight aircraft contains approximately 10% relative humidity (rh). To investigate the impact of this environment on eye comfort, an inflight humidity profile was simulated in a controlled laboratory setting. The experiment was replicated 3 times using a group of 4 subjects (2 males; 2 females) per test. Participants served in both control and experimental roles by wearing a hydrophilic contact lens on one eye and no lens on the other. Subjects provided evaluations of “eye comfort” for both eyes (contact and naked) at specified intervals during the 10 hour test. The results indicated that at 10% rh, there was no significant difference in eye comfort for either wearers or nonwearers of soft contact lenses. However, comfort decreased with the length of exposure (flight time), and for durations of six hours or longer a significant annoyance was reported.

Phylogenetic grouping and identification of Rhizobium isolates on the basis of random amplified polymorphic DNA profiles

1993 ◽  
Vol 39 (7) ◽  
pp. 665-673 ◽  
Author(s):  
John J. Dooley ◽  
Stephen P. Harrison ◽  
Lance R. Mytton ◽  
Malcolm Dye ◽  
Ann Cresswell ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
Rhizobium Meliloti ◽  
Random Amplified Polymorphic Dna ◽  
Dna Amplification ◽  
Distinct Group ◽  
Principal Coordinate Analysis ◽  
The Other ◽  
Phylogenetic Grouping ◽  
Dna Profiles ◽  
Selection Of

Through the use of a single, random 15mer as a primer, between 1 and 12 DNA amplification products were obtained per strain from a selection of 84 Rhizobium and Bradyrhizobium isolates. A principal-coordinate analysis was used to analyse the resulting amplified DNA profiles and it was possible to assign isolates to specific groupings. Within the species Rhizobium leguminosarum, the biovar phaseoli formed a distinct group from the other biovars of the species, viciae and trifolii, which grouped together. Isolates of Rhizobium meliloti and Bradyrhizobium species formed their own clear, specific groups. Although it was possible to identify individual isolates on the basis of differences in their amplified DNA profiles, there was evidence that some amplified segments were conserved among individuals at the biovar and species levels.Key words: Rhizobium, DNA amplification, random primers.

scholarly journals Analysis of Genetic Diversity among Selected Grasspea (Lathyrus sativus L.) Genotypes Using RAPD Markers

2007 ◽  
Vol 62 (11-12) ◽  
pp. 869-874 ◽  
Author(s):  
Durga P. Barik ◽  
Laxmikanta Acharya ◽  
Arup K. Mukherjee ◽  
Pradeep K. Chand
Keyword(s):  
Rapd Markers ◽  
Molecular Level ◽  
Crop Improvement ◽  
Dna Amplification ◽  
The Other ◽  
Randomly Amplified Polymorphic Dna ◽  
Similar Morphology ◽  
Molecular Weights ◽  
Breeding Programmes ◽  
Lathyrus Sativus L

Randomly amplified polymorphic DNA (RAPD) technique was applied to assess the genetic variability among five selected genotypes of grasspea. Out of 30 random decamer primers tested for the present investigation 20 showed reproducible DNA amplification. A total of 257 loci were amplified of which 159 were polymorphic including 57 genotype-specific unique bands. Amplicons had molecular weights ranging from 3.0 kb to 0.1 kb. Majority amplicons were shared by most of the genotypes which indicated a very narrow genetic gap between them. The dendrogram constructed on the basis of RAPD data showed two clusters. The local genotype collected from Nayagarh was grouped along with IC-120451 and IC-120453, sharing a common node at an 82% similarity level. The other genotypes, IC-120478 and IC-120487, were located in the second clade having a common node at 84% similarity level. The investigation showed that though all the genotypes of grasspea were of apparently similar morphology there exists polymorphism at the molecular level, which can be exploited in breeding programmes aimed at crop improvement.

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