P13.23 Study of migration characteristics of human glioma cells in vitro

BACKGROUND

Gliomas are still one of the most aggressive human cancers, and even despite modern therapeutic approaches, the prognosis for patients with this disease is not favorable. It is known that glioma cells are capable of local invasiveness, when glioma cells migrate into healthy brain tissue. A lack of any definite markers, characterizing migrating glioma cells and allowing them to be distinguished from healthy brain cells, requires a thorough investigation. In case it would be possible to characterize invasive glioma cells, then a development of targeted therapy could be feasible.

MATERIAL AND METHODS

Cell cultures of human gliomas Gr II, III and IV were developed with 5 cultures for each Grade. MTT, RT-PCR, Western and Nosern blot, transcriptome analysis were applied.

RESULTS

Three cultures of human gliomas had a high degree of migration, within the range of 6% - 14%. These cultures were developed from gliomas of Grade III and Grade IV, and with IDH1- (minus) phenotype. Moreover, cell cultures with IDH1 + (plus) phenotype had a low migration rate within 1%. An intensity of migration correlated with the degree of malignancy, and an average rate decreased with a decrease of the Grade. Moreover, an analysis of the proliferative activity of cell cultures of human gliomas of various degrees of malignancy did not reveal a relationship with a migratory properties of cultures. A number of actively proliferating cultures did not show high migration, while cultures with medium proliferative activity could show a high level of migration. The low level of proliferation of cultures of gliomas of Grade II and I at the beginning of cultivation, in some cases, subsequently increased, but an inherent low migration activity did not change. In actively migrating cultures, a significant decrease in the expression of Sox2 and Nestin is detected. A positive correlation was found between migration abilities of human glioma cell culture cells and the marker Ki67, GFAP, Sox2, and Oct4. The difference was statistically significant by the one-sided Mann-Whitney test.

CONCLUSION

Conclusions: Cell cultures derived from glioma tumor tissue can be used to predict invasive properties of the tumor. High tumor invasiveness is characteristic for Grade III and Grade IV, and with IDH1- (minus) phenotype, and it also correlates with elevated expression of GFAP, Sox2 and Oct4The reported study was funded by RFBR according to the research project № 18-29-01012 and by the Ministry of Science and Higher Education of the Russian Federation, grant number 075-15-2020-809 (13.1902.21.0030).

Femtosecond laser written waveguides deep inside silicon

Photonic devices that can guide, transfer, or modulate light are highly desired in electronics and integrated silicon (Si) photonics. Here, we demonstrate for the first time, to the best of our knowledge, the creation of optical waveguides deep inside Si using femtosecond pulses at a central wavelength of 1.5 μm. To this end, we use 350 fs long, 2 μJ pulses with a repetition rate of 250 kHz from an Er-doped fiber laser, which we focused inside Si to create permanent modifications of the crystal. The position of the beam is accurately controlled with pump-probe imaging during fabrication. Waveguides that were 5.5 mm in length and 20 μm in diameter were created by scanning the focal position along the beam propagation axis. The fabricated waveguides were characterized with a continuous-wave laser operating at 1.5 μm. The refractive index change inside the waveguide was measured with optical shadowgraphy, yielding a value of 6×10^-4, and by direct light coupling and far-field imaging, yielding a value of 3.5×10^-4. The formation mechanism of the modification is discussed.

Detailed analysis of therapy-driven clonal evolution of TP53 mutations in chronic lymphocytic leukemia

In chronic lymphocytic leukemia (CLL), the worst prognosis is associated with TP53 defects with the affected patients being potentially directed to alternative treatment. Therapy administration was shown to drive the selection of new TP53 mutations in CLL. Using ultra-deep next-generation sequencing (NGS), we performed a detailed analysis of TP53 mutations' clonal evolution. We retrospectively analyzed samples that were assessed as TP53-wild-type (wt) by FASAY from 20 patients with a new TP53 mutation detected in relapse and 40 patients remaining TP53-wt in relapse. Minor TP53-mutated subclones were disclosed in 18/20 patients experiencing later mutation selection, while only one minor-clone mutation was observed in those patients remaining TP53-wt (n=40). We documented that (i) minor TP53 mutations may be present before therapy and may occur in any relapse; (ii) the majority of TP53-mutated minor clones expand to dominant clone under the selective pressure of chemotherapy, while persistence of minor-clone mutations is rare; (iii) multiple minor-clone TP53 mutations are common and may simultaneously expand. In conclusion, patients with minor-clone TP53 mutations carry a high risk of mutation selection by therapy. Deep sequencing can shift TP53 mutation identification to a period before therapy administration, which might be of particular importance for clinical trials.

Synthesis gas production from bio-oil: steam reforming of ethanol as a model compound

Syngas production via ethanol steam reforming has been studied over solid Ru/Ce_0.5Zr_0.5O₂ and alumina supported Ru/Ce_0.4Zr_0.4Sm_0.2O₂ as granulated and monolithic catalysts.

Application of RT-PCR for diagnosis of respiratory syncytial virus and human metapneumovirus infections in Bulgaria, 2006-7 and 2007-8

We describe here the results of respiratory syncytial virus (RSV) detection by reverse transcription polymerase chain reaction (RT-PCR) during two consecutive seasons, from December 2006 to February 2007 and from October 2007 to March 2008, performed in the National Laboratory of Influenza and Acute Respiratory Diseases, Bulgaria. A total number of 278 nasopharyngeal samples obtained from hospitalised children up to the age of five years were investigated for these two seasons. During the first season, the aetiological role of RSV was confirmed in 56 of 148 samples (37.8%) compared to 11 of 130 samples (8.5%) during the second season. Since the beginning of January 2008, RT-PCR for the detection of the recently identified human metapneumovirus (HMPV) has also been introduced in Bulgaria. This virus has been demonstrated as the aetiological agent in 13 out of 81 samples (16%) from children of the same age group. The use of RT-PCR allows the detection of a broader spectrum of viruses causing respiratory diseases, as well as better discrimination of the aetiological agents in clinically similar cases.

Laboratory investigation of the first suspected human cases of infection with avian influenza A(H5N1) virus in Bulgaria

Reports of human cases of infection with avian influenza A(H5N1) virus have received increased public attention because of the potential for the emergence of a pandemic strain. In the end of 2005 and the beginning of 2006, avian influenza A(H5N1) virus caused outbreaks among domestic poultry and was isolated from wild swans in many European countries, including Bulgaria. Between January and March 2006, samples were collected from 26 patients who had been in close contact with ill or dead birds and developed a subsequent respiratory illness. The testing took place at the National Laboratory of Influenza in Sofia. Specific A(H5N1) assays were applied for screening (Sacace RT-PCR and real-time kit). Avian flu A(H5N1) virus was not detected in any of the patients tested. In three patients, human subtype A(H1N1) influenza virus, identifiable by RT-PCR was isolated and further characterized by hemagglutination inhibition test (HIT). The reliability of the molecular assays used in this investigation was demonstrated in an International Quality Control for Human and Avian A(H5N1) Influenza performed later in 2006 by INSTAND (Society for Promotion of Quality Assurance in the Medical Laboratories), Germany.

Laboratory investigation of the first suspected human cases of infection with avian influenza A(H5N1) virus in Bulgaria

Reports of human cases of infection with avian influenza A(H5N1) virus have received increased public attention because of the potential for the emergence of a pandemic strain. In the end of 2005 and the beginning of 2006, avian influenza A(H5N1) virus caused outbreaks among domestic poultry and was isolated from wild swans in many European countries, including Bulgaria. Between January and March 2006, samples were collected from 26 patients who had been in close contact with ill or dead birds and developed a subsequent respiratory illness. The testing took place at the National Laboratory of Influenza in Sofia. Specific ?(H5N1) assays were applied for screening (Sacace RT-PCR and real-time kit). Avian flu ?(H5N1) virus was not detected in any of the patients tested. In three patients, human subtype ?(H1N1) influenza virus, identifiable by RT-PCR was isolated and further characterized by hemagglutination inhibition test (HIT). The reliability of the molecular assays used in this investigation was demonstrated in an International Quality Control for Human and Avian ?(H5N1) Influenza performed later in 2006 by INSTAND (Society for Promotion of Quality Assurance in the Medical Laboratories), Germany.

Discriminating functional and non-functional p53 in human tumours by p53 and MDM2 immunohistochemistry

Mutation and/or loss of the TP53 tumour suppressor gene is the single most common genetic abnormality in human cancer. The majority of TP53 mutations lead to stabilization of the protein, so that immunohistochemical staining for p53 can suggest mutation status in many cases. However, various false-positive and false-negative situations mean that simple immunostaining for p53 is not informative in a substantial number of tumours. In the present study, a series of 119 human cancers were immunostained using a highly sensitive technique that detects the low levels of wild-type protein expressed in normal cells, such that homozygous gene deletion or non-sense TP53 mutation can be identified by an absence of staining. TP53 gene status was also assessed using FASAY as a genetic/functional screen and in selected cases by direct sequencing. A quantitative scoring system was employed to assess p53 levels, and p53 post-translational modification was evaluated using antibodies that detect specific phosphorylation sites. Phosphorylated p53 correlated with total p53 levels and did not improve the prediction of TP53 mutation status. The transcriptional activity of TP53 was determined by staining for two downstream target genes, p21(WAF1) and MDM2, and statistical correlations between MDM2/p21(WAF1) and p53 were found in tumours with wild-type, but not mutant TP53. Measurement of staining for p53 and MDM2 accurately identifies the TP53 status of tumours. This simple and cost-effective method, applicable to automated staining and quantitation methods, improves the identification of TP53 status over standard methods for p53 immunostaining and provides information about tumour p53 phenotype that is complementary to genotyping data.

Occupational exposure to lead and induction of genetic damage

To investigate whether occupational exposure to lead is genotoxic, we evaluated data from 103 lead-exposed workers and 78 matched controls. These data correspond to three different sampling periods, and we measured genetic damage as increases in the frequency of binucleated cells with micronuclei (BNMN) in peripheral blood lymphocytes. The levels of exposure were determined according to the lead levels in blood. Clearly significant increases in BNMN were observed in the exposed groups when compared to the control group. In addition, for the overall population (n = 181), we observed a clear relationship between lead levels in blood and BNMN (r = 0.497; p < 0.001). When we examined four exposure levels--very low exposure (< 1.20 microM/L), low exposure (1.20-1.91 microM/L), high exposure (1.92-2.88 microM/L), and very high exposure (> 2.88 microM/L)--we found significant differences in the genetic damage induction. We conclude that exposure to levels of lead higher than 1.20 microM/L may pose an increase in genetic risk. In addition, our data show that blood lead level is a good indicator of genetic damage induction.

Occupational exposure to lead and induction of genetic damage

To investigate whether occupational exposure to lead is genotoxic, we evaluated data from 103 lead-exposed workers and 78 matched controls. These data correspond to three different sampling periods, and we measured genetic damage as increases in the frequency of binucleated cells with micronuclei (BNMN) in peripheral blood lymphocytes. The levels of exposure were determined according to the lead levels in blood. Clearly significant increases in BNMN were observed in the exposed groups when compared to the control group. In addition, for the overall population (n = 181), we observed a clear relationship between lead levels in blood and BNMN (r = 0.497; p < 0.001). When we examined four exposure levels--very low exposure (< 1.20 microM/L), low exposure (1.20-1.91 microM/L), high exposure (1.92-2.88 microM/L), and very high exposure (> 2.88 microM/L)--we found significant differences in the genetic damage induction. We conclude that exposure to levels of lead higher than 1.20 microM/L may pose an increase in genetic risk. In addition, our data show that blood lead level is a good indicator of genetic damage induction.

[Lipid peroxidation in chronic lead exposure]

The state of lipid peroxidation, monitored by MDA concentration in the blood plasma of 46 battery workers with lead level in the blood in the 1.26-5.6 mol/l range is investigated. Higher MDA concentration (4.61 + 0.6) mol (ml in the blood plasma of exposed workers in comparison with the control sample of nonexposed workers is statistically established. The greater part of exposes workers (56.6%) have MDA concentration above the upper reference range. The significant correlation (r = +0.54) of the lipid peroxidation with the lead level in the blood is established. The investigation results show the rise of lipid peroxidation in workers chronically exposed to lead. This rise is more significant at lead levels above 1.92 mol/l.

[The effect of the zinc-containing preparation Oxyrich in the treatment of chronic saturnism (preliminary results)]

Under indoor conditions the effect of the Bulgarian zinc-containing preparation Oxyrich was studied in the treatment of 12 workers (males) with chronic saturnism. The preparation was orally administered in a dose of 150 mg (0.45 mmol Zn++) daily for 10 days in three equal receivings, after which three day antidotal therapy with CaNa2 EDTA was carried out according to the classic schedule. The complex investigation of the workers besides the clinical exmination included some key indices of the porphirine metabolism (5-ALK-D, 5-ALK, free protoporphirine in the red bolld cells), as well as the content of zinc and lead in the blood and their excretion with the urine prior and post the administration of Oxyrich and CaNa2 EDTA. The results of the carried out study revealed that the therapy with Oxyrich demonstrated a tendency to normalization of the activity of 5-ALK-D and decrease of the elimination of 5-ALK. This gave grounds for further study with higher doses of Oxyrich, as well as enlargement of the spectrum of the indices of the porphirine metabolism.

[The impact of trinitrotoluene on eyes in miners]

Trinitrotoluene (TNT) effect on the eyes of 250 miners was studied. The length of service of the investigated group varied from one to twenty years. The specific trinitrotoluene cataract of various stages was observed in 54.7% of the examinees. The authors assume that the lens changes depend on the length of service and on the TNT concentrations in the body after predominant skin penetration.

Immunomodulatory action of propolis. V. Anticomplementary activity of a water-soluble derivative

The effect of a water-soluble derivative (WSD) of propolis on the classical pathway (CP) and the alternative (AP) complement activity has been investigated. The in vitro experiments show that WSD inhibits both pathways and the effect depends on the source of complement. The suppression of complement-mediated haemolysis proves to be time- and temperature-related. High WSD concentrations cause direct damage of the target erythrocytes. The estimation of C3-residual activity indicates that the preparation diminishes C3 functional activity.

[Evaluation of initial results of treatment of lead poisoning with EDTA]

The results of EDTA therapy were studied in 37 workers of a battery factory consisting of males with varying degrees of occupational lead poisoning (low exposure: 10 subjects, blood lead levels (PbB) lower than 400 micrograms/l with slight alterations in heme biosynthesis; beyond limit of effect: 5 subjects, PbB > 400 micrograms/l; slight intoxication: 19 subjects, with marked alterations in heme synthesis and preclinical signs of intoxication; average degree of intoxication: 3 subjects with clinical signs of intoxication. Clinical symptoms and the following parameters were investigated: blood lead (PbB), delta-aminolevulinic acid dehydratase in erythrocytes (ALA-D), zinc protoporphyrin (PP) in erythrocytes and delta-aminolevulinic acid (ALA) in 24-hour urine before and after EDTA chelating therapy. Simultaneous measurement of ALA-D and PP showed high diagnostic sensitivity in detecting lead poisoning in occupationally exposed subjects. In view of the high interindividual variability of the results, these indices did not, however, permit a useful differentiation to be made of the different degrees of intoxication at individual level, even though a good correlation was observed between PbB and porphyrin metabolism indices. From the alterations observed in ALA-D and PP values it was not possible to establish an association between degree of alteration and types of clinical symptoms in the different intoxication studies. At the end of EDTA treatment, a clinical improvement was observed in all cases studied but only in 5 cases was a reduction in PbB observed, to levels below 1.20 mol/l, which is accepted as a permissible limit for the general population; in 17 cases PbB remained at levels above the critical value for occupational lead poisoning (400 micrograms/l), although there was a decrease after treatment. The improvement observed in the indices of porphyrin metabolism at the end of treatment was only slight: significant variations were measured only for PbB. After treatment no association was observed between ALA-D and PP variations in erythrocytes and improvement in clinical symptoms; measurement of these indices therefore seems to be of little use in assessing the efficacy of the treatment. In spite of its limited diagnostic sensitivity during intoxication, measurement of ALA in urine could be useful to assess the efficacy of chelating therapy in subjects in whom the values are initially altered.

Complications of pregnancy in relation to maternal lipid peroxides, glutathione, and exposure to metals

Lipid peroxides, glutathione, and metals (lead, cadmium, and arsenic) were measured in pregnant women residing in the vicinity of a copper smelter. A diagnosis of pregnancy complications experienced by each woman was made on the basis of interview and clinical record. Patients were assigned to groups of normal or pathologic pregnancies (threatened spontaneous abortion, toxemia, and anemia) according to this diagnosis. Biochemical changes suggestive of increased lipid peroxidation and decreased antioxidant protection (involving the reduced: oxidized glutathione balance) were found in the diagnostic groups of pregnancy complications. These changes were independent of measured maternal variables. Maternal exposure to metals (as indicated by blood lead and cadmium) was associated with a decrease in reduced glutathione in blood. Since increased lipid peroxidation has been implicated in other studies as a pathogenetic factor for maternal toxemia, it is suggested that exposure to metals during gestation could enhance the development of pregnancy complications by increasing lipid peroxidation via depletion of reduced glutathione reserves.

Assessment of circulating agglutinating anti-sperm antibodies in buffalo cows with unexplained infertility and an attempt to identify buffalo sperm isoantigens

The presence of circulating agglutinating anti-sperm antibodies as cause for unexplained infertility of artificially inseminated buffalo cows was assessed. An attempt to identify buffalo sperm isoantigens was also made. The following methods were applied for that purpose: the tray agglutination test (TAT), SDS-polyacrylamide gel electrophoresis, and immunoblotting. The results obtained showed that three of 90 sera from buffalo cows with unexplained infertility were positive in TAT (3.3%) and their titers were low. A total of 27 spermatozoal polypeptides reacted positively with the IgG-isoantibodies of one of the sperm agglutinating sera in immunoblotting. Of the control sera 12 also revealed individual variations in the number of positive fractions on the blots. On the basis of comparing the blot with the positive sperm agglutinating serum to the blots of the positive controls, two buffalo sperm isoantigens were identified, with the respective molecular weights of 40 kDa and 120 kDa. In conclusion, circulating agglutinating anti-sperm antibodies are very rarely detected in buffalo cows with unexplained infertility after several artificial inseminations.