[The information value of detection of borrelia antibodies in the healthy blood donors and in the population at risk]

BACKGROUND

Geographic differences of particular species of ticks and variant strains of Borrelias impede the comparison of local and foreign experience. The authors tried to support some literary observations with their own results and designed a study aimed at determination of anti-Borrelia antibodies (AB) in the selected population samples. The goal of the study was to find and statistically evaluate: a) difference in distribution of values of AB in the sample of probands from the risk and non-risk environment (foresters in Sumava and Prague blood donors, respectively) by means of ELISA method, b) tick bite frequency in the risk and non-risk groups, c) to determine and statistically evaluate the prevalence of probands with increased levels of antiborrelial antibodies in the local study population by ELISA method and the prevalence of probands with non-normal values found by Western blot (WB) method.

METHODS AND RESULTS

In the group of Prague blood donors (control group), in total 200 probands were examined; in the risk group, 71 probands from Sumava forest were examined. Blood specimens were examined in the National Reference Laboratory for Lyme Borreliosis in Prague. In all specimens, ELISA NRLB KC90 was used. Western blot assay was used for confirmation.

CONCLUSIONS

On the basis of literature review from Europe and USA, it is possible to generalize the following, despite some equivocations: 1. regional differences are not significant, with the exception of high-risk territories or "occupational exposure"; 2. there is no significant difference between males and females; 3. considerable caution is necessary in comparing the control and risk groups; prerequisite for such comparison is defining the characteristics of both groups.

Lyme borreliosis infection as a cause of dilated cardiomyopathy

The relatively low percent of patients affected with the cardiac form of Lyme borreliosis is difficult to diagnose, especially if the disease manifests itself in ways other than atrio-ventricular blockade. The advanced stage of Lyme carditis manifesting as dilated cardiomyopathy is a special case of this affliction. The authors of this report present clinical experience with an attempt to support the working hypothesis about involvement of Lyme borreliosis infection in the development of dilated cardiomyopathy. The patients were clinically examined thoroughly with special attention to the cardiovascular system. In addition to the basic clinical methods, the following procedures have been employed: dynamic Holter's electrocardiography, exercise ECG test, coronarography, and myocardial biopsy. From laboratory methods pertaining to the detection of Borrelia, ELISA method, Western blot, PCR, electron microscopy and histopathological analysis were used. In all three cases, clinical and laboratory findings provided the evidence of the borreliosis infection involvement in the development of dilated cardiomyopathy.

Lyme borreliosis--waiting for Lyme carditis? A long-term prospective study

A long-term prospective study of patients with confirmed non-cardiac form of Lyme disease (n=221) over a mean follow-up period of 40.6 months is reported. The study revealed no case of Borrelia-related cardiac involvement developed after several years in patients who had received antibiotic therapy in the early period. Therefore, these patients do not need follow-up by a cardiologist.

The leucine zipper region of Myb oncoprotein regulates the commitment of hematopoietic progenitors

The development of blood cells proceeds from pluripotent stem cells through multipotent progenitors into mature elements belonging to at least 8 different lineages. The lineage choice process during which stem cells and progenitors commit to a particular lineage is regulated by a coordinated action of extracellular signals and transcription factors. Molecular mechanisms controlling commitment are largely unknown. Here, the transcription factor v-Myb and its leucine zipper region (LZR) are identified as regulators of the commitment of a common myeloid progenitor and progenitors restricted to the myeloid lineage. It is demonstrated that wild-type v-Myb with the intact LZR directs development of progenitors into the macrophage lineage. Mutations in this region compromise commitment toward myeloid cells and cause v-Myb to also support the development of erythroid cells, thrombocytes, and granulocytes, similar to the c-Myb protein. In agreement with that, the wild-type v-Myb induces high expression of myeloid factors C/EBP beta, PU.1, and Egr-1 in its target cells, whereas SCL, GATA-1, and c-Myb are more abundant in cells expressing the v-Myb LZR mutant. It is proposed that Myb LZR can function as a molecular switch, affecting expression of lineage-specifying transcription factors and directing the development of hematopoietic progenitors into either myeloid or erythroid lineages.

The Myb leucine zipper is essential for leukemogenicity of the v-Myb protein

The AMV v-Myb oncoprotein causes oncogenic transformation of myelomonocytic cells in vivo and in vitro. Its transforming capacity is strictly dependent upon the N-terminal DNA binding domain, the central transactivation region, and on the C-terminal domain containing a putative leucine zipper motif. Here we show that the v-MybL3,4A mutant, in which Leu325 and Leu332 of the leucine zipper have been replaced by alanines, failed to induce leukemia in virus infected chicken. This demonstrates that the leucine zipper domain is indispensable for v-myb induced leukemogenesis in vivo. v-MybL3,4A was, however, still able to transform myelomonocytic cells from chicken bone marrow in vitro. Yet, while v-mybL3,4A transformed cells were impaired in growth at 37 degrees C, they failed to grow at 42 degrees C, the physiological body temperature of avian species. This might explain the loss of v-MybL3,4A leukemogenic potential in vivo. We also demonstrate that the v-Myb leucine zipper domain interacts in vitro with two host cell proteins, p26 and p28. This interaction is compromised in v-MybL3,4A indicating that binding of v-Myb to p26 and p28 might be important for the leukemogenic potential of v-Myb.