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Results for “Sampling Errors”

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At least 73 records · Page 4Linked to original sources
PubMed2001

Genetic sampling error of distance (delta(mu))2 and variation in mutation rate among microsatellite loci.

An expression is obtained for the time-dependent variance of the microsatellite genetic distance (delta(mu))2 when the mutation rate is allowed to vary randomly among loci. An estimator is presented for the coefficient of variation, C(w), in the mutation rate. Estimated values of C(w) from genetic distances between African and non-African populations were less than 100%. Caveats to this conclusion are discussed.

Humans↗
PubMed2003

Sampling error in the standard evaluation of endoscopic colonic biopsies.

It is assumed that the diagnostic information in small gastrointestinal mucosal biopsies is obtained regardless of which side of the biopsy is sectioned. Based on this assumption, mucosal biopsies of the colon are embedded randomly with respect to the side of the biopsy that faces the microtome blade. Our hypothesis is that reorienting ("flipping") the biopsy specimen 180 degrees and sectioning the opposite side might provide new diagnostic information in cases with no specific histopathologic diagnosis. Sixty-one consecutive cases with a clinical impression of a polyp and no histologic abnormality on three hematoxylin and eosin-stained slides (6-15 levels) were selected. Formalin-fixed, paraffin-embedded tissue was reoriented, and three additional hematoxylin and eosin-stained slides (6-15 levels) were evaluated. The side of the specimen initially sectioned was arbitrarily designated "A," and the side of the specimen sectioned after reembedding was designated "B." The slides were sequentially numbered 1-3, and the first slide on which the new diagnosis was evident was recorded. New diagnoses were made for 19 of 61 (31.1%) specimens from a total of 51 patients and included tubular adenomas (12 of 61; 19.7%) and hyperplastic polyps (7 of 61; 11.5%). In 17 of 19 specimens (89.5%), the new diagnosis was evident on the first slide. Reembedding endoscopic colonic biopsies facilitates rendering a definitive diagnosis in cases of discordance between the clinical impression and the histologic impression. Routine examination of at least two sides of randomly oriented biopsy material could provide additional diagnostic, and sometimes critical, information.

Biopsy↗
PubMedDate not supplied

Sampling, sampling errors and specimen preparation.

To obtain an adequate cervical smear for making a correct cytologic diagnosis, smear taking, laboratory handling and interpretation must be optimal. Many people are involved, and only by a combined effort of all links can this target be seriously approached: the smear takers will have to be open minded about technical improvements and read the morphologic descriptions cautiously; in the laboratory, cytotechnicians and physicians will have to challenge themselves and each other. It is mandatory to discard specimens that do not meet general standards of adequacy. At present a host of new techniques are being implemented. It is not feasible for all laboratories to be engaged in testing these new methods, but we are all requested to follow the development the best we can and switch to new ways when justified. Our working conditions are very different; therefore, it is our professional responsibility and plight to respond at the right time. So far the conclusion is that the conventional Pap smear is the international standard of care for the diagnosis of cervical cancer precursers in cancer screening programs. Certainly, this may change within a very short time. Liquid-based techniques, and in particular HPV technologies, are just around the corner.

Cell Biology↗