Melanoacanthoma is a rare benign mixed tumor of both keratinocytes and melanocytes. Although some authors said that it is a rare variant of seborrheic keratosis, it has clinical and histological features distinct from seborrheic keratosis. It has large dendritic melanin-laden melanocytes throughout all levels of epidermis showing a disruption of melanin transfer from the melanocytes to neighbor...

Fractions of rat liver microsomal phospholipid that inhibit gulonolactone oxidase are described. The inhibition was shown to be complete and occurs rapidly after the reaction has proceeded at the control rate for 20 to 30 min. It could be totally reversed by the addition of tocopherol, Mn++, Co++, or ethylenediaminetetraacetate. The inhibitory activity of the phospholipid was lost by enzymic cl...

The cytological dilemma of distinguishing malignant cells from proliferating mesothelium has generated volumes of research but no clear consensus regarding an optimal staining panel. nm23 has been frequently described in malignant cells as a metastasis suppressor, but its mechanism of action and the relationship between nm23 expression, metastases, and prognosis is controversial. This is the fi...

Immunohistochemical stains are indispensable for problem solving in diagnostic pathology. In order to evaluate them appropriately, it is critical to be aware of the characteristics of a true positive stain and a false positive stain. A "true positive" stain shows chromogen deposition in cells or structures that truly contain the antigen of interest. In contrast, a "false positive" stain is one ...

A simple spectrophotometric assay for serum guanase based on the oxidation of 2,2'-azino-di(3-ethylbenzthiazoline-6-sulphate) (ABTS) using xanthine oxidase, uricase and peroxidase is described and statistically examined through its application to normal and pathological sera. The method is very sensitive, precise (CV below 8.13%) and linear up to 152.5 U/l. Comparison with the methods of Hue & ...

Localization of specific mRNA molecules within large and diverse sample sets is often hampered by the limitations of traditional in situ hybridization (ISH) methods. RNAscope ISH is an improved method for localizing mRNA molecules more specifically, more rapidly, and with greater sensitivity than previously possible with conventional ISH methods. RNAscope ISH utilizes pairs of ‘Z-probes’ that a...

PURPOSE The aim of our study was to characterize and describe the different immunohistochemical expression patterns of cytokeratin 8/18 (CK8/18) in breast tumors and to make a correlation between histopathology, immunohistochemistry for CK8/18 and its possible diagnostic value of this pair of keratins for molecular classification of breast cancers. MATERIAL AND METHODS Forty cases of breast t...

A laboratory prototype of a microcomputer-based analyzer was developed for quantitative determination of formaldehyde in liquid samples, based on catalytic chemosensing elements. It was shown that selectivity for the target analyte could be increased by modulating the working electrode potential. Analytical parameters of three variants of the amperometric analyzer that differed in the chemical ...

Evaluating an enzyme immunoassay (EIA) procedure based on antibody coated on solid-phase materials for assay of triiodothyronine (T3) (1), we observed a considerable improvement in the precision of this assay when the antibody coating on solid-phase matrix was carried out with shaking. In the EIA procedure, the coated beads are incubated with 30 pg of horseradish peroxidase-labeled T3 and T3 st...

We have developed a rapid and cost-effective enzyme immunoassay for dehydroepiandrosterone sulfate (DHEA-S) in plasma, performed with samples on a microtitre plate within 2.5 h. No extraction or centrifugation steps are involved. The 3-hemisuccinate of dehydroepiandrosterone is labeled with horseradish peroxidase, then mixed with hydrogen peroxide substrate in the presence of the chromogen, tet...