Mapping of a small phosphopeptide at the carboxyterminus of the viral myb protein by monoclonal antibodies.

Several myb-specific monoclonal antibodies were produced and their antigen recognition sites characterized using a series of bacterially expressed truncated myb proteins. The monoclonal antibodies were used for analysing the in vivo phosphorylation site of the oncogene protein from avian myeloblastosis virus (AMV), p48v-myb. The p48v-myb protein labeled metabolically with [32P]orthophosphate was isolated from the AMV-transformed chicken myeloblast cell line BM-2 by immunoaffinity chromatography. Phosphoamino acid analysis indicated that it was phosphorylated mainly on serine and to a lesser extent (less than 5%) on threonine residues. Indirect immunoprecipitation of phosphopeptides from trypsin-digested [32P]-labeled purified p48v-myb protein by use of the myb-specific monoclonal antibodies allowed the mapping of a small phosphopeptide at the carboxyterminus of p48v-myb.

Differential expression of the oncoproteins c-myc and c-myb in human lymphoproliferative disorders.

Altered regulation of oncogene expression has been described in a variety of hematopoietic malignancies. In this study we analyzed the protein level of c-myc and c-myb in 15 established cell lines derived from lymphopoietic disorders and in 45 samples from patients with acute or chronic lymphatic leukemias. Oncoproteins were assayed by radioimmuno-precipitation with polyclonal rabbit antibodies. In B-cell derived lines, such as Burkitt lymphoma and plasmocytoma lines, we found high amounts of c-myc and no or low amounts of c-myb. In contrast, all T-cell-derived lines revealed high levels of c-myb. In addition, T-lymphoma cell lines of low malignancy also exhibited high levels of c-myc, while T-cell lines of high malignancy (acute T-lymphoblastic leukemias) exhibited moderate levels of c-myc. Of the 45 patient samples analyzed, only three (one B-prolymphocytic and two acute T-lymphoblastic leukemias) contained detectable amounts of myc or myb protein. Corresponding to the results found in established cell lines, the B-cell sample revealed a high level of c-myc but no c-myb, while the T-cell samples revealed high levels of c-myb and no or low levels of c-myc. We therefore conclude that the predominance of c-myc or c-myb expression in malignant lymphoproliferative disorders may be associated to the B-cell or T-cell lineage, respectively. Further, regarding the T-cell lines, there is a possible correlation between cell maturation and the level of c-myc found together with a consistently elevated c-myb.

Incidental finding of double minutes (DM), single minutes (SM), homogenously staining regions (HSR), premature chromosome condensation (PCC), and premature centromere division (PCD)?

The incidental finding of DM's, minutes, HSR's, PCC, and PCD in two completely unrelated cases--one is a prenatal diagnosis in a twin pregnancy complicated by hydramnios and feto-fetal exsanguination, the other is an adult Klinefelter patient--raises the question whether such findings are coincidental or whether there is a common denominator in such cases. Possible relationships between these phenomena and the observed cases are discussed.

Cryotherapy modifies synthetic activity and differentiation of keloidal fibroblasts in vitro.

In order to obtain a persuasive explanation for the beneficial clinical effect of cryotherapy on keloids, we developed a reproducible model to apply freezing temperatures on cell cultures, and investigated their influence on proliferation, viability, synthetic activity and differentiation of dermal fibroblasts in vitro. Cell cultures were established from 13 untreated keloids and 10 healthy skin specimens matched for age and skin localization to the donors. No significant influence of cell freezing on the proliferation rates of both keloidal and normal fibroblasts was documented, but mechanical cell destruction with a wide variation in lethality rates (29% average lethal effect on keloidal fibroblasts and 41% on normal ones) was observed. When comparing specimens of keloidal and normal tissue derived from the same four donors, the keloidal fibroblasts were similar regarding their synthetic activity but presented enhanced tenascin-C expression compared with the normal fibroblasts. After cryotherapy, delayed collagen III increase was detected in both cell types (P = 0.03). The collagen II/collagen I ratio increased from 1.6 to 2.8 in the keloidal and only from 1.9 to 2.2 in the normal fibroblasts after subcultivation. Normal fibroblasts exhibited a significantly lasting increase in fibronectin synthesis after freezing (P = 0.03). The intensity of staining against tenascin-C was decreased in five of nine keloidal fibroblast cultures after cryotherapy (P < 0.05) but increased in four of five normal fibroblast cultures (P = 0.016), so that the intensity of tenascin-C staining after freezing became identical in both cell types. Immunoblot studies in four patients and two controls confirmed a temporary decrease of tenascin-C in keloidal but not in normal fibroblasts immediately after freezing. Significantly decreased staining with two markers of myogenic differentiation, myosin in keloidal fibroblasts (P = 0.002) and desmin (P = 0.007) in normal fibroblasts, could also be detected after treatment. In summary, with the help of a model for controlled cell freezing in vitro, cryotherapy was found to modify collagen synthesis and differentiation of keloidal fibroblasts.

[COX-2-expression in extragenital endometriosis lesions as a novel therapeutical approach?]. / COX-2-Expression in extragenitalen Endometrioseläsionen als neuer Therapieansatz?

OBJECTIVE: Extragenital endometriosis is a rare form of endometriosis. Due to its invasive and metastatic properties it resembles some features of malignant tumours. Cyclooxygenase (COX)-2 is a rate-limiting enzyme in the biosynthesis of prostaglandins and is mainly expressed in inflammatory and malignant processes. In this study we investigated the COX-2 expression in extragenital endometriosis. MATERIAL AND METHODS: Tissue was obtained of 13 women with rectal and vaginal endometriosis, scar endometriosis and endometriosis of the omentum majus. The COX-2 expression was investigated by immunohistochemistry. RESULTS: In the glandular epithelium a COX-2 overexpression was found in all cases and in the stroma a weak to moderate COX-2 expression was found in half of the cases. A hormonal therapy at the time of surgery had no influence on the COX-2 expression in extragenital endometriosis. CONCLUSION: The high COX-2 expression in extragenital endometriosis is believed to be strongly correlated with the pathological abnormalities this of disease.

A final word on the tricho-rhino-phalangeal syndromes.

Chromosomal findings in the majority of cases of TRP II (or Langer-Giedion) syndrome and in some cases of TRP I syndrome lead to the conclusion that the former is due to a deletion extending from 8q24.11 to 8q24.13 whereas the latter is caused by an even smaller deleted segment, namely 8q24.12. A case of tricho-rhino-phalangeal syndrome type I with a mosaic deletion of band 8q24.12 is described.