CD147, CD44, and the epidermal growth factor receptor (EGFR) signaling pathway cooperate to regulate breast epithelial cell invasiveness.

The immunoglobulin superfamily glycoprotein CD147 (emmprin; basigin) is associated with an invasive phenotype in various types of cancers, including malignant breast cancer. We showed recently that up-regulation of CD147 in non-transformed, non-invasive breast epithelial cells is sufficient to induce an invasive phenotype characterized by membrane type-1 matrix metalloproteinase (MT1-MMP)-dependent invadopodia activity (Grass, G. D.

CD147-dependent heterogeneity in malignant and chemoresistant properties of cancer cells.

CD147 (alias emmprin or basigin), an integral plasma membrane glycoprotein and a member of the Ig superfamily, is widespread in normal tissues, but highly up-regulated in many types of malignant cancer cells. CD147 is multifunctional, with numerous binding partners. Recent studies suggest that complexes of CD147 with the hyaluronan receptor CD44 and associated transporters and receptor tyrosine kinases are enriched in the plasma membrane of cancer stem-like cells.

Regulation of invadopodia formation and activity by CD147.

A defining feature of malignant tumor progression is cellular penetration through the basement membrane and interstitial matrices that separate various cellular compartments. Accumulating evidence supports the notion that invasive cells employ specialized structures termed invadopodia to breach these structural barriers. Invadopodia are actin-based, lipid-raft-enriched membrane protrusions containing membrane-type-1 matrix metalloproteinase (MT1-MMP; also known as matrix metalloproteinase 14; MMP14) and several signaling proteins.

Inhibition of heart formation by lithium is an indirect result of the disruption of tissue organization within the embryo.

Lithium is a commonly used drug for the treatment of bipolar disorder. At high doses, lithium becomes teratogenic, which is a property that has allowed this agent to serve as a useful tool for dissecting molecular pathways that regulate embryogenesis. This study was designed to examine the impact of lithium on heart formation in the developing frog for insights into the molecular regulation of cardiac specification.

KSHV activation of VEGF secretion and invasion for endothelial cells is mediated through viral upregulation of emmprin-induced signal transduction.

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma (KS)-one of the most common tumors arising in the setting of immune suppression. Hallmarks of KS lesions include KSHV-infected cells of endothelial lineage and neoangiogenesis. Promigratory factors secreted in the tumor microenvironment by KSHV-infected cells promote endothelial cell (EC) migration and angiogenesis but existing therapies targeting these pathways are not widely utilized.

Cooperative roles for emmprin and LYVE-1 in the regulation of chemoresistance for primary effusion lymphoma.

The Kaposi's sarcoma-associated herpesvirus is the causative agent of primary effusion lymphoma (PEL), for which cytotoxic chemotherapy represents the standard of care. The high mortality associated with PEL may be explained in part by resistance of these tumors to chemotherapy. The membrane-bound glycoprotein emmprin (CD147) enhances chemoresistance in tumors through effects on transporter expression, trafficking and interactions.

Canonical WNT signaling enhances stem cell expression in the developing heart without a corresponding inhibition of cardiogenic differentiation.

WNT signaling has been shown to influence the development of the heart. Although recent data suggested that canonical WNTs promote the emergence and expansion of cardiac progenitors in the pregastrula embryo, it has long been accepted that once gastrulation begins, canonical WNT signaling needs to be suppressed for cardiac development to proceed. Yet, this latter supposition appears to be odds with the expression of multiple canonical WNTs in the developing heart.

High-frequency ultrasonographic imaging of avian cardiovascular development.

The chick embryo has long been a favorite model system for morphologic and physiologic studies of the developing heart, largely because of its easy visualization and amenability to experimental manipulations. However, this advantage is diminished after 5 days of incubation, when rapidly growing chorioallantoic membranes reduce visibility of the embryo. Using high-frequency ultrasound, we show that chick embryonic cardiovascular structures can be readily visualized throughout the period of Stages 9-39.

Characteristics of virulence signs of enteroinvasive Escherichia coli (EIEC) isolated in CSFR and Bulgaria in 1988-1990.

During 1988-1990 a total of 345 virulent and avirulent strains of enteroinvasive E. coli (EIEC) were isolated from human faeces in microbiological laboratories in Prague and Sofia. This group of strains belonged to a total of 11 serotypes.

A case of diarrhea, bacteremia, and fever caused by a novel strain of Escherichia coli.

A nonenteropathogenic strain of Escherichia coli from a patient with diarrhea and bacteremia possessed the attaching-effacing eae gene, was invasive in the gentamicin invasion assay, and expressed two types of pili and K1 antigen. This unique combination places the strain in a new category of attaching-effacing E. coli.

In vivo R-plasmid transfer in a patient with a mixed infection of shigella dysentery.

Transfer of shigella R-plasmids in vivo has seldom been demonstrated. Strains of Shigella dysenteriae type 1 and Shigella flexneri type 5b were isolated from a Bulgarian traveller who visited Vietnam and developed dysentery, which was treated with trimethoprim/sulfamethoxazole (TMP/SMZ) for a short time. Both species of shigellae are unusual in Bulgaria where strains of S.

Activities of newer fluoroquinolones against Shigella sonnei.

The activities of six fluoroquinolones were determined for 117 separate strains of Shigella sonnei. The order of increasing activity (MICs for 90% of strains tested) was enoxacin (0.25 micrograms/ml), temafloxacin (0.

Molecular epidemiology of trimethoprim-resistant Shigella boydii serotype 2 strains from Bulgaria.

In 1990 an increased number of strains of Shigella boydii serotype 2 were isolated from different regions of Bulgaria. Strains were reported as sporadic, although they showed identical phenotypic characteristics, including resistance to ampicillin, carbenicillin, streptomycin, sulfonamide, tetracycline, ticarcillin, and trimethoprim. The objective of this study was to determine the genetic relatedness of the strains and the mechanism of their antimicrobial resistance.

A case of shigellosis caused by Shigella dysenteriae type 1 and Shigella flexneri type 5B.

Shigella dysenteriae type 1 and Shigella flexneri type 5b strains were isolated as causative agents of bacterial dysentery in a patient having visited South-East Asia. Both strains are a rare finding for Bulgaria. S.

Technological aspect of the production of live dysentery vaccines for oral administration.

An experimental technology for the production of live freeze-dried vaccines prepared from attenuated Shigella flexneri 2a and Shigella sonnei I strains was developed. It is based on the cultivation of bacterial strains in a fermentor under conditions which ensure high yields. The strains grow in S-form, their antigenic structure is preserved and they remain non-virulent.

Characterization of enteroinvasive Escherichia coli serotype 0164 by means of plasmid analysis and virulence assay.

Escherichia coli 0164 is the most prevalent serotype among the enteroinvasive E. coli in Bulgaria and is annually isolated in sporadic, as well in epidemic cases. We studied 243 strains of this serotype, isolated in different regions of the country over the period 1954-1988.

Dissemination of trimethoprim-resistant clones of Shigella sonnei in Bulgaria.

Bacterial dysentery due to Shigella sonnei remains a serious public health problem in developed countries, including Bulgaria. At the National Shigella Reference Laboratory in Sofia, 17,126 strains of S. sonnei from epidemics and sporadic cases collected from 1973 to 1987 were studied.

[Stability of Shigella flexneri attenuated strain 2A 77 ADE- RIF-r after cultivation in a fermenter and lyophilization].

The method for the cultivation of S. flexneri attenuated strain 2a 77 ade- rifr in a fermenter with the use of casein fermentative broth containing 200-250 mg% of amino nitrogen has been developed. No changes in the properties of the initial strain have been found after its cultivation in a fermenter or after the lyophilization of the cultures grown in a fermenter.

Technological investigations with attenuated strains of Shigella for production of live vaccines. 1. Cultivation in a fermenter of an attenuated strain S. flexneri 2a with two markers.

A method was developed for cultivation of the strain Shigella flexneri 2a 77 with two attenuated markers. It ensures the preservation of the initial properties of the strain. The regimen for control of dissolved oxygen level was optimized.

Microbiological methods and plasmid pattern analysis in epidemiological control of Shigella sonnei infections.

Shigella sonnei plays an important aetiological role in bacillary dysentery. Advances in methodology for the study of intraspecies differentiation are proving to be valuable in the epidemiological analysis of infections caused by this agent.

[Combined use of microbiological methods for the intraspecific differentiation of Shigella sonnei. II. The role of S. sonnei strains belonging to unclassifiable phagotypes in the etiology of dysentery in the People's Republic of Bulgaria].

The phage typing of S. sonnei strains in Bulgaria during 1973-1983 revealed that 10.07% of these strains could not be classified with the known phage types in accordance with the international scheme of Hammarstrom-Kallings.

[Combined use of microbiological methods for the intraspecific differentiation of Shigella sonnei. The use of the S. sonnei phage typing method in the People's Republic of Bulgaria].

The data on the use of the method for S. sonnei phage typing in Bulgaria during the period of 1973-1980 were analyzed. The comparative study with the use of two sets of phages (international and Bulgarian) were carried out.

[Distribution of transferable trimethoprim and gentamicin resistance plasmids in Enterobacteriaceae].

Following the employment of trimethoprim/sulfonamid and gentamicin in the general clinical praxis transferable plasmids with respective resistance function were identified at first in enteric bacteria from sewage before they could be detected in patient strains. Whereas the trimethoprim resistance plasmids represent different incompatibility groups (C, FII, I5, K, M, N, S, U) the gentamicin resistance plasmids are very similar IncM members of 62 MD in size. Therefore a clonal distribution of a particular gentamicin resistance plasmid has to be taken into consideration.

Studies on R-plasmid-determined drug resistance in serotypes 792 (E. coli O 28a28c:K73) and 145-46 (E. coli O 164).

The drug resistance of 2368 strains belonging to serotypes 792 (E. coli O 28a28c:K73) and 145-46 (E. coli O 164) was studied.