[Secondary spondylogenic epidural abscess]. / Vtorichnyi spondilogennyi épidural'nyi abstsess.

The article presents the results of a retrospective analysis of 200 patients with hematogenous osteomyelitis of the spine who were treated in the Tyumen Regional Clinical Hospital #2. Neurological disorders were present in 37 patients (group I); 163 patients (group II) had no neurological disorders; according to CT and MRI, secondary spondylogenic epidural abscess was diagnosed in 24 patients. At admission, the severity of neurological deficit assessed using the Frankel scale was as follows: Grade A - 6 cases, Grade B - 7 cases, Grade C - 17 cases, Grade D - 5 cases, and Grade E - 2 cases (epidural abscess without neurological deficit). At discharge, the severity of neurological deficit was as follows: Grade A - 3 cases, Grade B - 2 cases, Grade C - 13 cases, Grade D - 11 cases, and Grade E - 8 cases. In group I, 35 out of 37 patients underwent surgery; of these, 21 patients had improvements. There were no statistically significant differences in neurological deficit changes between patients with and without epidural abscess. In 12 patients, the neurological status remained unchanged. Two patients died. We present an analysis of the severity of neurological symptoms, depending on the spinal lesion level, and the results of microbiological tests. Changes in neurological symptoms in lesions of various spinal parts are described. Cervical spine lesions and the process caused by S. aureus are shown to significantly increase the risk of neurological disorders. An active surgical approach for complicated forms of spinal osteomyelitis provided partial or complete regression of neurological disorders in 62.2% of cases.

A tumor-suppressing function in the epithelial adhesion protein Trask.

Trask/CDCP1 is a transmembrane glycoprotein widely expressed in epithelial tissues whose functions are just beginning to be understood, but include a role as an anti-adhesive effector of Src kinases. Early studies looking at RNA transcript levels seemed to suggest overexpression in some cancers, but immunostaining studies are now providing more accurate analyses of its expression. In an immuno-histochemical survey of human cancer specimens, we find that Trask expression is retained, reduced or sometimes lost in some tumors compared with their normal epithelial tissue counterparts. A survey of human cancer cell lines also show a similar wide variation in the expression of Trask, including some cell types with the loss of Trask expression, and additional cell types that have lost the physiological detachment-induced phosphorylation of Trask. Three experimental models were established to interrogate the role of Trask in tumor progression, including two gain-of-function models with tet-inducible expression of Trask in tumor cells lacking Trask expression, and one loss-of-function model to suppress Trask expression in tumor cells with abundant Trask expression. The induction of Trask expression and phosphorylation in MCF-7 cells and in 3T3v-src cells was associated with a reduction in tumor metastases while the shRNA-induced knockdown of Trask in L3.6pl cancer cells was associated with increased tumor metastases. The results from these three models are consistent with a tumor-suppressing role for Trask. These data identify Trask as one of several potential candidates for functionally relevant tumor suppressors on the 3p21.3 region of the genome frequently lost in human cancers.

A modest reduction in c-myc expression has minimal effects on cell growth and apoptosis but dramatically reduces susceptibility to Ras and Raf transformation.

Dergulation of c-myc and mutation of ras genes is commonly found in many human tumors. Several lines of evidence indicate that c-Myc and oncogenic Ras cooperate in causing malignant transformation, but the mechanism of this cooperation is not understood. We set out to investigate the effect on transformation of a modest reduction in endogenous c-Myc expression, which was achieved using a c-myc heterozygous cell line constructed by targeted homologous recombination. In contrast to previous reports where c-Myc expression or activity was ablated using antisense or dominant-defective methods, use of c-myc +/- cells provides a stable and homogeneous cell culture system with a precisely defined c-Myc expression level. In addition, this approach does not suffer from nonspecific artifacts such as antisense oligonucleotide toxicity or interference of dominant-defective proteins with multiple (and often undefined) target proteins. The striking and unexpected finding communicated here is that the relatively modest 50% reduction in c-Myc expression resulted in a greater than 10-fold reduction in susceptibility to transformation by oncogenic Ras or Raf proteins. This very significant defect in transformation potential cannot be explained on the basis of a generalized cell-cycle defect, because c-myc +/- cells exhibit only a minimal (20%) reduction in proliferation. Genetic epistasis analysis indicated that c-Myc and Ras acted by independent pathways that converged to regulate the abundance of the cyclin-dependent kinase inhibitor protein p27Kip1. Anchorage deprivation elicited a strong up-regulation of p27, and a 50% reduction in c-Myc expression significantly compromised the ability of Ras to down-regulate p27. We propose that Ras and c-Myc signals cooperate to regulate the activity of cyclin D-Cdk4/6 complexes: the former by up-regulating the expression of cyclin D1 and the latter by affecting the activity of the complexes. Ectopic expression of cyclin A restored the transformation potential of c-myc +/- cells, implicating it as a downstream genetic component in the pathway. From a therapeutic standpoint, it is of interest that, although transformation appears to be very sensitive to c-Myc expression levels, much larger reductions can be tolerated without causing any significant cell cycle defects.

Isolation of temperature-sensitive mutations in the c-raf-1 catalytic domain and expression of conditionally active and dominant-defective forms of Raf-1 in cultured mammalian cells.

The c-Raf-1 kinase is converted into an oncoprotein by functional inactivation of its NH2-terminal regulatory domain and into a dominant-interfering protein by mutations that eliminate catalytic activity. This report describes a systematic charged residue-to-alanine scanning mutagenesis of the ATP-binding subdomain of the c-raf-1 gene. Two temperature-sensitive mutations were found, which were then used to construct both conditionally active and conditionally dominant-defective alleles. Stable cell lines overexpressing both types of mutants were isolated, and their phenotypes were examined. Ectopic expression of Raf-1 activity in quiescent cells was not sufficient to elicit S-phase entry, but the Raf signal could be efficiently complemented by the progression factor insulin-like growth factor I. The results point to a function of Raf-1 in the platelet-derived growth factor and epidermal growth factor pathways, leading to the establishment of competence for cell cycle entry. Ectopic expression of the dominant-defective activity in quiescent cells efficiently blocked entry into S phase. Effects of the dominant-defective protein could be detected minutes after the shift to the restrictive conditions and resulted in the rapid down-regulation of the mitogen-activated protein kinase pathway. Taken together, the phenotypes of the conditionally active and conditionally dominant-defective mutants point to a critical function of Raf-1 at very early times during exit from G0 and entry into G1.

Inhibition of the Raf-1 kinase by cyclic AMP agonists causes apoptosis of v-abl-transformed cells.

Here we investigate the role of the Raf-1 kinase in transformation by the v-abl oncogene. Raf-1 can activate a transforming signalling cascade comprising the consecutive activation of Mek and extracellular-signal-regulated kinases (Erks). In v-abl-transformed cells the endogenous Raf-1 protein was phosphorylated on tyrosine and displayed high constitutive kinase activity. The activities of the Erks were constitutively elevated in both v-raf- and v-abl-transformed cells. In both cell types the activities of Raf-1 and v-raf were almost completely suppressed after activation of the cyclic AMP-dependent kinase (protein kinase A [PKA]), whereas the v-abl kinase was not affected. Raf inhibition substantially diminished the activities of Erks in v-raf-transformed cells but not in v-abl-transformed cells, indicating that v-abl can activate Erks by a Raf-1-independent pathway. PKA activation induced apoptosis in v-abl-transformed cells while reverting v-raf transformation without severe cytopathic effects. Overexpression of Raf-1 in v-abl-transformed cells partially protected the cells from apoptosis induced by PKA activation. In contrast to PKA activators, a Mek inhibitor did not induce apoptosis. The diverse biological responses correlated with the status of c-myc gene expression. v-abl-transformed cells featured high constitutive levels of expression of c-myc, which were not reduced following PKA activation. Myc activation has been previously shown to be essential for transformation by oncogenic Abl proteins. Using estrogen-regulated c-myc and temperature-sensitive Raf-1 mutants, we found that Raf-1 activation could protect cells from c-myc-induced apoptosis. In conclusion, these results suggest (i) that Raf-1 participates in v-abl transformation via an Erk-independent pathway by providing a survival signal which complements c-myc in transformation, and (ii) that cAMP agonists might become useful for the treatment of malignancies where abl oncogenes are involved, such as chronic myeloid leukemias.

[Concentration of the poliomyelitis virus from water on FP-brand material]. / Kontsentrirovanie virusa poliomeilita iz vody na materiale marki FP.

A method of filtration through FP cloth (Petryanov's cloth) has been suggested for concentration of small virus quantities from large volumes of water. The effectiveness of virus removal from water of different degrees of contamination at virus concentrations of 0.05--0.1--0.5--2.5--12.5 PFU/ml was studied. About 88--100% of the initial virus content was removed from sewage, 80--90% from river water, 10--90% from tap water. When the effect of the eluting solutions for the removal of the virus retained on the filter was compared, 1 M NaCl solution in glycocol buffer, pH 11.5, was found to be the most effective. The procedure is characterized by a high rate of filtration, low labour consumption, and simple equipment for filtration.