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Melanoma inhibitory activity (MIA) is a small soluble protein secreted by malignant melanoma cells and chondrocytes. Prior studies suggested that MIA expression was relatively tissue-specific, making it a potentially useful marker for melanoma. The current investigations sought to more clearly define the range of tumor/tissue-types where MIA is expressed, compared with expression of 4 other potential melanoma marker genes (tyrosinase melanoma antigen recognized by T cells [MART-1/MelanA], gp100, and melanoma growth-stimulatory activity [MGSA/Gro alpha]). Expression of these genes was assayed by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry in 23 melanoma tumor specimens and in 25 additional nonmelanoma or nonmalignant specimens. MIA, tyrosinase, and MGSA were expressed in most melanoma specimens. Specificity was highest for MART-1, followed by MIA and tyrosinase. Increasing the number of cycles of amplification from 35 to 40 increased sensitivity but decreased specificity of most markers, though MIA was relatively robust. MIA mRNA was also detected in carcinomas of the colon, ovary, kidney, and head/neck, as well as in normal laryngeal epithelium. Although MIA discriminated melanoma from nonmelanoma at least as well as tyrosinase, no single mRNA marker had accuracy greater than 71%, raising potential concern about application of these particular mRNA markers to the minimal disease setting. HUM PATHOL 31:1381-1388.

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Transthyretin (TTR) aggregation has been characterized to be responsible for several amyloid diseases. Fourier transform infrared (FTIR) spectroscopy, �uorescence, and atomic force microscopy (AFM) are used to investigate secondary structure changes in transthyretin, induced upon thermal denaturation and interaction with pentobarbital. Spectral analysis revealed a strong static quenching of the intrinsic �uorescence of TTR by pentobarbital with a binding constant (�) estimated at 2.092 × 10 3 M −1 . Fourier self-deconvolution (FSD) technique is used to evaluates intensity changes in the spectra of the component bands in the amide I and amide II regions due to the changes in pentobarbital concentration in the protein complex. e increases of the relative intensities of the peaks at 1614 cm −1 and 1507 cm −1 are due to the increase of pentobarbital concentrations which is linked to the formation of oligomers in the protein.

Analysis of structural diversity at the 5' end of H-2 class I mRNAs showed that a small fraction of Kd mRNA from L1210 lymphoma (approximately 10%) or from various normal tissue (2-3%) of DBA/2 mice carries a precise deletion of the sequences encoding the second extracellular domain. Nucleotide sequence of the coding region of the second domain-lacking Kd mRNA was found to be identical to the known sequence of the Kd gene from DBA/2 liver with the exception of the above deletion and a single nucleotide silent substitution at position 150, suggesting that the novel Kd RNA is a product of the functional Kd gene. In addition, various normal tissues that are known to express varying levels of Kd antigen did not show changes in the expression levels of the second domain-lacking Kd mRNA thus ruling out the possibility that synthesis of this RNA is coupled to control the expression levels of the canonical Kd mRNA, hence the Kd antigen. Analysis by polymerase chain reaction showed that all normal tissues including the testis and sperm express this RNA. Preliminary analysis of the Kb mRNA from the spleen and thymus of C57BL/6 mouse also showed the presence of second domain-lacking Kb mRNA in these mice. Furthermore, preliminary structural analysis of the Dd and Ld mRNAs has revealed additional polymorphic extracellular domain-lacking mRNA species including a first domain-lacking Dd mRNA and two Ld mRNAs that lack sequences encoding either the first extracellular domain or the second extracellular domain respectively. These results together show that H-2 mRNAs lacking sequences that specify individual extracellular polymorphic domains are a frequent feature of the structural diversity at the 5' ends of these mRNAs. Potential significance of these domain-lacking H-2 mRNAs is discussed, particularly with regard to the function of the putative encoded peptides as targets of natural killer cells.

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