Reporting on reliability and validity of outcome measures in medical rehabilitation research.

PURPOSE: To evaluate the degree to which published medical rehabilitation research offers evidence of reliability, validity and other clinimetric qualities of the data reported. METHOD: Descriptive study of published intervention research papers published in six US medical rehabilitation journals in 1997 and 1998. Selected characteristics of the papers and the outcome measures used were abstracted by one or two raters. RESULTS: The 171 papers identified included 651 outcome measures. Some type of data reliability information was provided for 20.1% of these measures; for validity, this was 6.9%. However, this information was based on data collected for the sample studied for only 7.7% (reliability) and 0.6% (validity). CONCLUSIONS: Most rehabilitation research falls short of standards, including the Standards promulgated by an American Congress of Rehabilitation Medicine Advisory Group. Authors, peer reviewers and editors need to change their practices to improve this situation.

Single-step multiplex PCR assay for characterization of New World Leishmania complexes.

We have developed a PCR assay for one-step differentiation of the three complexes of New World Leishmania (Leishmania braziliensis, Leishmania mexicana, and Leishmania donovani). This multiplex assay is targeted to the spliced leader RNA (mini-exon) gene repeats of these organisms and can detect all three complexes simultaneously, generating differently sized products for each complex. The assay is specific to the Leishmania genus and does not recognize related kinetoplastid protozoa, such as Trypanosoma cruzi, Trypanosoma brucei, and Crithidia fasciculata. It correctly identified Leishmania species with a broad geographic distribution in Central and South America. The sensitivity of the PCR amplification ranged from 1 fg to 10 pg of DNA (0.01 to 100 parasites), depending on the complex detected. Crude extracts of cultured parasites, prepared simply by boiling diluted cultures, served as excellent templates for amplification. Crude preparations of clinical material were also tested. The assay detected L. braziliensis in dermal scrapings from cutaneous leishmanial lesions, Leishmania chagasi in dermal scrapings of atypical cutaneous leishmaniasis, and L. mexicana from lesion aspirates from infected hamsters. We have minimized the material requirements and maximized the simplicity, rapidity, and informative content of this assay to render it suitable for use in laboratories in countries where leishmaniasis is endemic. This assay should be useful for rapid in-country identification of Leishmania parasites, particularly where different Leishmania complexes are found in the same geographical area.

Asymmetrically primed selective amplification/temperature shift fluorescence polymerase chain reaction to detect the hemoglobin Constant Spring mutation.

Hemoglobin (Hb) Constant Spring is an alpha-thalassemic hemoglobinopathy that is a major cause of severe alpha-thalassemia in Southeast Asians. The difficulty of diagnosing Hb Constant Spring using standard electrophoretic methods has led to interest in DNA-dependent diagnostic methods. The methods developed have had to contend with the high degree of homology of the alpha 2-globin gene (the site of the Hb Constant Spring mutation) and the alpha 1-globin gene. We have developed a single reaction polymerase chain reaction-based method that uses asymmetric priming and a temperature shift to accomplish dual ends, selective amplification of alpha 2 but not alpha 1 DNA and discrimination of normal and Hb Constant Spring alpha 2 genes by allele-specific fluorescence polymerase chain reaction. Advantages of this method over previous approaches include avoiding radioisotopes, precluding the need for electrophoresis, and serving as its own control for successful amplification. It is readily applicable to routine diagnosis, population screening, and prenatal diagnosis.

Detection of the hemoglobin E mutation using the color complementation assay: application to complex genotyping.

The color complementation assay (CCA) is a method of allele-specific DNA amplification by which competitive priming and extension of fluorescently labeled oligonucleotide primers determine the color of DNA amplification product. This diagnostic method precludes the need for radioisotopes, electrophoresis, and multiple high-stringency reaction conditions. The multiplicity of mutant globin genes present in Southeast Asians complicates clinical diagnosis and underscores the importance of DNA-based diagnostic methods. We have applied CCA to distinguish beta A and beta E alleles. Competing 15mer primers were a fluorescein-labeled complement to beta A and a rhodamine-labeled complement to beta E, identical except for their central nucleotides. A common unlabeled primer was used to amplify DNA product, the color of which was determined by the perfectly complementary primer. Color photography and spectrofluorometry, as well as a method of black-white photography that we developed to distinguish fluorescein- and rhodamine-labeled DNA, were used to record results. We applied CCA to define the complex genotype of a Thai woman with thalassemia intermedia, 96% HbE, and 4% HbF whose possible genotypes included several permutations of alpha-thalassemia, beta-thalassemia, and beta E genes. zeta-Globin gene mapping of DNA doubly digested with Bg/II and Asp 718 showed the -alpha 3.7/--SEA genotype, and CCA confirmed homozygous beta E/beta E. The CCA is useful for diagnosing the compound hemoglobin genotypes of Southeast Asians and could be applied also to prenatal diagnosis in this population.

Selective enzymatic amplification of alpha 2-globin DNA for detection of the hemoglobin Constant Spring mutation.

Hemoglobin Constant Spring is an elongation mutation of the alpha 2-globin locus that results in a thalassemic phenotype. It has a high prevalence in Asian populations. When inherited with other alpha-thalassemia determinants, the Constant Spring gene has the potential to cause severe forms of alpha-thalassemia. Accurate diagnosis of the condition with standard hemoglobin electrophoresis is unreliable due to the small to undetectable amounts of the mutant hemoglobin present. Because of the extensive sequence homology of the alpha 1 and alpha 2 loci, allele-specific hybridization to total genomic DNA containing the Constant Spring gene would not distinguish between heterozygous and homozygous hemoglobin Constant Spring. Selective enzymatic amplification of alpha 2-globin DNA sequences, however, allows unambiguous diagnoses to be made using allele-specific hybridization. This method is useful for providing accurate genetic counseling and prenatal diagnosis in populations and specific families in which precise diagnosis is important.

[Excision and removal of multiple polyps of the colon (author's transl)]. / Massenpolypektomien und Bergungsmodus im Kolon

Nowadays polyps in the gastrointestinal tract are usually removed under endoscopy, the method being highly effective and of low risk. Endoscopic removal, if necessary in several sessions, can be easily done even if there are multiple polyps of the colon. Altogether 69 polyps were removed from a 33-year-old woman, their microscopic appearance showing various degrees of proliferation. Complete removal of the polyp is of decisive importance, accomplished by enema wash-out. The diagnostic point of polypectomy lies in the histological assessment of the entire material which has been removed.