Loss of Lamin A leads to the nuclear translocation of AGO2 and compromised RNA interference.

In mammals, RNA interference (RNAi) was historically studied as a cytoplasmic event; however, in the last decade, a growing number of reports convincingly show the nuclear localization of the Argonaute (AGO) proteins. Nevertheless, the extent of nuclear RNAi and its implication in biological mechanisms remain to be elucidated. We found that reduced Lamin A levels significantly induce nuclear influx of AGO2 in SHSY5Y neuroblastoma and A375 melanoma cancer cell lines, which normally have no nuclear AGO2. Lamin A KO manifested a more pronounced effect in SHSY5Y cells compared to A375 cells, evident by changes in cell morphology, increased cell proliferation, and oncogenic miRNA expression. Moreover, AGO fPAR-CLIP in Lamin A KO SHSY5Y cells revealed significantly reduced RNAi activity. Further exploration of the nuclear AGO interactome by mass spectrometry identified FAM120A, an RNA-binding protein and known interactor of AGO2. Subsequent FAM120A fPAR-CLIP, revealed that FAM120A co-binds AGO targets and that this competition reduces the RNAi activity. Therefore, loss of Lamin A triggers nuclear AGO2 translocation, FAM120A mediated RNAi impairment, and upregulation of oncogenic miRNAs, facilitating cancer cell proliferation.

Integrative transcriptomic and proteomic profiling of the effects of cell confluency on gene expression.

In this study we examine the impact of cell confluency on gene expression. We focused on Argonaute (AGO) protein dynamics and associated gene and protein expression in HEK293, A375, and SHSY5Y cell lines. As a consequence of cell confluency, AGO2 protein translocates into the nucleus. Therefore, we generated transcriptomic data using RNA sequencing to compare gene expression in subconfluent versus confluent cells, which highlighted significant alterations in gene regulation patterns directly corresponding to changes in cell density. Our study also encompasses miRNA profiling data obtained through small RNA sequencing, revealing miRNA expressional changes dependent on cellular confluency, as well as cellular localization. Finally, we derived proteomic data from mass spectrometry analyses following AGO1-4 immunoprecipitation, providing a comprehensive view of AGO interactome in both nuclear and cytoplasmic compartments under varying confluency. These datasets offer a detailed exploration of the cellular and molecular dynamics, influenced by cell confluency, presenting a valuable resource for further research in cellular biology, particularly in understanding the basic mechanisms of cell density in cancer cells.

Drug-Modified Contact Lenses-Properties, Release Kinetics, and Stability of Active Substances with Particular Emphasis on Cyclosporine A: A Review.

The following review focuses on the manufacturing and parameterizing of ocular drug delivery systems (DDS) using polymeric materials to create soft contact lenses. It discusses the types of drugs embedded into contact lenses, the various polymeric materials used in their production, methods for assessing the mechanical properties of polymers, and techniques for studying drug release kinetics. The article also explores strategies for investigating the stability of active substances released from contact lenses. It specifically emphasizes the production of soft contact lenses modified with Cyclosporine A (CyA) for the topical treatment of specific ocular conditions. The review pays attention to methods for monitoring the stability of Cyclosporine A within the discussed DDS, as well as investigating the influence of polymer matrix type on the stability and release of CyA.

Apoptosis is responsible for the cytotoxic effects of anti-GD2 ganglioside antibodies and aurora A kinase inhibitors on human neuroblastoma cells.

In recent years, immunotherapy has been identified as an effective treatment method for high-risk neuroblastoma. A previous study demonstrated that an anti-GD2 ganglioside (GD2) mouse 14G2a monoclonal antibody (mAb) combined with a small molecule, i.e., an aurora A kinase inhibitor (MK-5108), significantly increased cytotoxicity against human neuroblastoma cells, as compared to monotherapy. This study aimed to demonstrate the mechanism of neuroblastoma cell death in vitro following the addition of an anti-GD2 human-mouse chimeric ch14.18/CHO mAb (presently used in clinics) and two aurora A inhibitors (MK-5108 and MK-8745). The effects of the aforementioned agents on neuroblastoma cells were determined by measuring the level of ATP, the level of apoptotic and necroptotic markers, and the activity of caspase 3/7. The results revealed that the ch14.18/CHO mAb decreased cellular ATP levels in the IMR-32 and CHP-134 neuroblastoma cell lines, similarly to the 14G2a mAb. Regarding ch14.18/CHO mAb treated IMR-32 cells, the observed cytotoxic effect was concomitant with induced caspase 3 cleavage, which indicated the induction of apoptosis in IMR-32 cells, but not in CHP-134 cells. Furthermore, the MK-5108 inhibitor induced apoptosis, as indicated by the increased cleavage of caspase 3 and increased activity of caspase 3/7. However, the presence of necroptosis was ruled out in MK-5108-treated IMR-32 and CHP-134 cells. In summary, the effects of the combination of ch14.18/CHO mAb and aurora A kinase inhibitors (MK-5108 and MK-8745) were shown to enhance apoptosis in IMR-32 cells compared to when used individually.

Soft Contact Lenses as Drug Delivery Systems: A Review.

This review describes the role of contact lenses as an innovative drug delivery system in treating eye diseases. Current ophthalmic drug delivery systems are inadequate, particularly eye drops, which allow about 95% of the active substance to be lost through tear drainage. According to the literature, many interdisciplinary studies have been carried out on the ability of contact lenses to increase the penetration of topical therapeutic agents. Contact lenses limit drug loss by releasing the medicine into two layers of tears on either side of the contact lens, eventually extending the time of contact with the ocular surface. Thanks to weighted soft contact lenses, a continuous release of the drug over an extended period is possible. This article reviewed the various techniques to deliver medications through contact lenses, examining their advantages and disadvantages. In addition, the potential of drug delivery systems based on contact lenses has been extensively studied.

Argonaute Proteins Take Center Stage in Cancers.

Argonaute proteins (AGOs) play crucial roles in RNA-induced silencing complex (RISC) formation and activity. AGOs loaded with small RNA molecules (miRNA or siRNA) either catalyze endoribonucleolytic cleavage of target RNAs or recruit factors responsible for translational silencing and target destabilization. miRNAs are well characterized and broadly studied in tumorigenesis; nevertheless, the functions of the AGOs in cancers have lagged behind. Here, we discuss the current state of knowledge on the role of AGOs in tumorigenesis, highlighting canonical and non-canonical functions of AGOs in cancer cells, as well as the biomarker potential of AGO expression in different of tumor types. Furthermore, we point to the possible application of the AGOs in development of novel therapeutic approaches.

MCPIP1 expression positively correlates with melanoma-specific survival of patients, and its overexpression affects vital intracellular pathways of human melanoma cells.

The suppressive activity of monocyte chemoattractant protein 1-induced protein 1 (MCPIP1) an inflammation-related ribonuclease, has been described in a few cancer types but has yet to be assessed in the most common subtype of skin cancer: melanoma. Here, we have evaluated the MCPIP1 expression in melanoma tissues by reanalysis of publicly available transcriptome data from 89 melanoma samples, and immunohistochemical staining of 21 primary and 81 metastatic melanomas. Our data implicated decreased MCPIP1 expression in melanoma tumors compared to normal tissues, and positive correlation between high ribonuclease expression and melanoma-specific survival of patients. To investigate the ribonuclease activity in melanoma cells, MCPIP1 was ectopically expressed in the MV3 human melanoma cell line. Following the transcriptome, proteome, and intracellular signaling of MCPIP1-overexpressing MV3 cells was assessed via real-time quantitative polymerase chain reaction, Western blot analysis, and RNAseq. MV3 cells overexpressing MCPIP1 exhibited a broad range of alterations in the transcriptome and proteome, as well as in the phosphorylation status of a number of proteins, strongly indicating MCPIP1-dependent cell cycle arrest and inhibition of Akt/mTOR signaling in these cells. Moreover, we have shown, that MCPIP1 overexpression downregulates miRNA-193a-3p expression in MV3 cells. Furthermore, the majority of the described effects were dependent on the ribonucleolytic activity of the protein. The presented body of data strongly suggests a potential tumor suppressor role and possible future application as a positive prognostic marker of MCPIP1 protein in melanoma.

MCPIP1 ribonuclease can bind and cleave AURKA mRNA in MYCN-amplified neuroblastoma cells.

The role of the inflammation-silencing ribonuclease, MCPIP1 (monocyte chemoattractant protein-induced protein 1), in neoplasia continuous to emerge. The ribonuclease can cleave not only inflammation-related transcripts but also some microRNAs (miRNAs) and viral RNAs. The suppressive effect of the protein has been hitherto suggested in breast cancer, clear cell renal cell carcinoma, osteosarcoma, and neuroblastoma. Our previous results have demonstrated a reduced levels of several oncogenes, as well as inhibited growth of neuroblastoma cells upon MCPIP1 overexpression. Here, we investigate the mechanisms underlying the suppression of MYCN proto-oncogene, bHLH transcription factor (MYCN)-amplified neuroblastoma cells overexpressing the MCPIP1 protein. We showed that the levels of several transcripts involved in cell cycle progression decreased in BE(2)-C and KELLY cells overexpressing MCPIP1 in a ribonucleolytic activity-dependent manner. However, RNA immunoprecipitation indicated that only AURKA mRNA (encoding for Aurora A kinase) interacts with the ribonuclease. Furthermore, the application of a luciferase assay suggested MCPIP1-dependent destabilization of the transcript. Further analyses demonstrated that the entire conserved region of AURKA seems to be indispensable for the interaction with the MCPIP1 protein. Additionally, we examined the effect of the ribonuclease overexpression on the miRNA expression profile in MYCN-amplified neuroblastoma cells. However, no significant alterations were observed. Our data indicate a key role of the binding and cleavage of the AURKA transcript in an MCPIP1-dependent suppressive effect on neuroblastoma cells.

Endoscopic dacryocystorhinostomy with circumostial mitomycin C injection, simultaneous limited septoplasty and the use of tissue glue.

Epiphora due to nasolacrimal duct obstruction is a common condition worsening one's quality of life. It requires surgical treatment. We present a combined technique of transnasal endoscopic dacryocystorhinostomy with simultaneous limited septoplasty, circumostial mitomycin C injection and the use of tissue glue in a case of a 72-year-old patient with nasolacrimal duct obstruction complicated by septal deviation. The multiprocedure surgery was performed successfully. Follow-up time was 2 years. The patient remained asymptomatic within the observation time. Functional and anatomical success was achieved. We believe that the transnasal endoscopic dacryocystorhinostomy extended by limited endoscopic septoplasty, circumostial mitomycin C injection and the use of fibrin glue may be a solution for selected cases of nasolacrimal obstruction accompanied by significant local septal deviation.

MCPIP1 overexpression in human neuroblastoma cell lines causes cell-cycle arrest by G1/S checkpoint block.

Monocyte chemoattractant protein-1-induced protein 1 (MCPIP1) has a multidomain structure, which assures its pleiotropic activity. The physiological functions of this protein include repression of inflammatory processes and the prevention of immune disorders. The influence of MCPIP1 on the cell cycle of cancer cells has not been sufficiently elucidated. A previous study by our group reported that overexpression of MCPIP1 affects the cell viability, inhibits the activation of the phosphoinositide-3 kinase/mammalian target of rapamycin signalling pathway, and reduces the stability of the MYCN oncogene in neuroblastoma (NB) cells. Furthermore, a decrease in expression and phosphorylation levels of cyclin-dependent kinase (CDK) 1, which has a key role in the M phase of the cell cycle, was observed. On the basis of these previous results, the purpose of our present study was to elucidate the influence of MCPIP1 on the cell cycle of NB cells. It was confirmed that ectopic overexpression of MCPIP1 in two human NB cell lines, KELLY and BE(2)-C, inhibited cell proliferation. Furthermore, flow cytometric analyses and imaging of the cell cycle with a fluorescence ubiquitination cell-cycle indicator test, demonstrated that overexpression of MCPIP1 causes an accumulation of NB cells in the G1 phase of the cell cycle, while the possibility of an increase in G0 phase due to induction of quiescence or senescence was excluded. Additional assessment of the molecular machinery responsible for the transition between the cell-cycle phases confirmed that MCPIP1 overexpression reduced the expression of cyclins A2, B1, D1, D3, E1, and E2 and decreased the phosphorylation of CDK2 and CDK4, as well as retinoblastoma protein. In conclusion, the present results indicated a relevant impact of overexpression of MCPIP1 on the cell cycle, namely a block of the G1/S cell-cycle checkpoint, resulting in arrest of NB cells in the G1 phase.

Exogenous expression of miRNA-3613-3p causes APAF1 downregulation and affects several proteins involved in apoptosis in BE(2)-C human neuroblastoma cells.

MicroRNAs (miRNAs) are a class of small non­coding RNAs involved in post­transcriptional gene regulation. Furthermore, dysregulation of miRNA expression is an important factor in the pathogenesis of neuroblastoma. Our previous study identified that overexpression of monocyte chemoattractant protein­induced protein 1 protein led to a significant downregulation of a novel miRNA molecule, miRNA­3613­3p. In the present study, the potential involvement of miRNA­3613­3p in the cell biology of neuroblastoma was investigated. It was identified that the expression of miRNA­3613­3p varies among a range of human neuroblastoma cell lines. As the delineation of the functions of a miRNA requires the identification of its target genes, seven putative mRNAs that may be regulated by miRNA­3613­3p were selected. Furthermore, it was identified that overexpression of miRNA­3613­3p causes significant downregulation of several genes exhibiting tumor suppressive potential [encoding apoptotic protease­activating factor 1 (APAF1), Dicer, DNA fragmentation factor subunit ß, von Hippel­Lindau protein and neurofibromin 1] in BE(2)­C human neuroblastoma cells. APAF1 mRNA was the most significantly decreased transcript in the cells with miRNA­3613­3p overexpression. In accordance with the aforementioned results, the downregulation of cleaved caspase-9 and lack of activation of executive caspases in BE(2)­C cells following miRNA­3613­3p overexpression was observed. The results of the present study suggest a potential underlying molecular mechanism of apoptosis inhibition via APAF1 downregulation in human neuroblastoma BE(2)­C cells with miRNA­3613­3p overexpression.

GD2 ganglioside-binding antibody 14G2a and specific aurora A kinase inhibitor MK-5108 induce autophagy in IMR-32 neuroblastoma cells.

The process of autophagy and its role in survival of human neuroblastoma cell cultures was studied upon addition of an anti-GD2 ganglioside (GD2) 14G2a mouse monoclonal antibody (14G2a mAb) and an aurora A kinase specific inhibitor, MK-5108. It was recently shown that combination of these agents significantly potentiates cytotoxicity against IMR-32 and CHP-134 neuroblastoma cells in vitro, as compared to the inhibitor used alone. In this study we gained mechanistic insights on autophagy in the observed cytotoxic effects exerted by both agents using cytotoxicity assays, RT-qPCR, immunoblotting, and autophagy detection methods. Enhancement of the autophagy process in the 14G2a mAb- and MK-5108-treated IMR-32 cells was documented by assessing autophagic flux. Application of a lysosomotropic agent-chloroquine (CQ) affected the 14G2a mAb- and MK-5108-stimulated autophagic flux. It is our conclusion that the 14G2a mAb (40 µg/ml) and MK-5108 inhibitor (0.1 µM) induce autophagy in IMR-32 cells. Moreover, the combinatorial treatment of IMR-32 cells with the 14G2a mAb and CQ significantly potentiates cytotoxic effect, as compared to CQ used alone. Most importantly, we showed that interfering with autophagy at its early and late step augments the 14G2a mAb-induced apoptosis, therefore we can conclude that inhibition of autophagy is the primary mechanism of the CQ-mediated sensitization to the 14G2a mAb-induced apoptosis. Although, there was no virtual stimulation of autophagy in the 14G2a mAb-treated CHP-134 neuroblastoma cells, we were able to show that PHLDA1 protein positively regulates autophagy and this process exists in a mutually exclusive manner with apoptosis in PHLDA1-silenced CHP-134 cells.

MCPIP1 Exogenous Overexpression Inhibits Pathways Regulating MYCN Oncoprotein Stability in Neuroblastoma.

The main physiological function of MCPIP1 (regnase-1) is negative regulation of inflammation. Moreover, roles of regnase-1 in apoptosis and differentiation have also been described, but its involvement in cancer is yet to be fully recognized. Earlier, we showed a lack of expression of MCPIP1 in both primary tumors and several neuroblastoma cell lines. Additionally, we reported that levels of MCPIP1 and the key neuroblastoma oncoprotein-MYCN were inversely correlated in BE(2)-C clones overexpressing the MCPIP1 gene. Here, we show that exogenous expression of the MCPIP1 protein decreases MYCN mRNA and protein levels without changing the MYCN mRNA half-life. Furthermore, it was shown that MCPIP1-wt exogenous expression affects levels and phosphorylation of MYCN partners such as Aurora A (Thr288), CDC2 (Tyr15 and Thr161), GSK3ß (Ser9), and key cellular components of Akt/mTOR signaling, which regulate MYCN stability and activation. In accordance with the obtained results, we found increased phosphorylation of MYCN protein at Thr58 that causes destabilization of the oncoprotein. Moreover, it is shown that exogenous expression of MCPIP1 does not cause apoptosis. Our data extend knowledge on roles of MCPIP1 in our model and link the protein to regulation of expression and stability of MYCN through decrease of signaling via Akt/mTOR pathway. J. Cell. Biochem. 118: 1741-1755, 2017. © 2016 Wiley Periodicals, Inc.

Monocyte Chemoattractant Protein-Induced Protein 1 Overexpression Modulates Transcriptome, Including MicroRNA, in Human Neuroblastoma Cells.

The recently discovered MCPIP1 (monocyte chemoattractant protein-induced protein 1), a multidomain protein encoded by the MCPIP1 (ZC3H12A) gene, has been described as a new differentiation factor, a ribonuclease, and a deubiquitination-supporting factor. However, its role in cancer is poorly recognized. Our recent analysis of microarrays data showed a lack of expression of the MCPIP1 transcript in primary neuroblastoma, the most common extracranial solid tumor in children. Additionally, enforced expression of the MCPIP1 gene in BE(2)-C cells caused a significant decrease in neuroblastoma proliferation and viability. Aim of the present study was to further investigate the role of MCPIP1 in neuroblastoma, using expression DNA microarrays and microRNA microarrays. Transient transfections of BE(2)-C cells were used for overexpression of either wild type of MCPIP1 (MCPIP1-wt) or its RN-ase defective mutant (MCPIP1-ΔPIN). We have analyzed changes of transcriptome and next, we have used qRT-PCR to verify mRNA levels of selected genes responding to MCPIP1 overexpression. Additionally, protein levels were determined for some of the selected genes. The choline transporter, CTL1, encoded by the SLC44A1 gene, was significantly repressed at the specific mRNA and protein levels and most importantly this translated into a decreased choline transport in MCPIP1-overexpressing cells. Then, we have found microRNA-3613-3p as the mostly altered in the pools of cells overexpressing the wild type MCPIP1. Next, we analyzed the predicted targets of the miR-3613-3p and validated them using qRT-PCR and western blot. These results indicate that the expression of miR-3613-3p might be regulated by MCPIP1 by cleavage of its precursor form.

[Influenza in Poland in 2008]. / Grypa w Polsce w 2008 roku.

A total number of 227,346 cases of influenza and influenza-like illness were registered in Poland in 2008 (incidence 596.5 per 100,000 population). Compared to 2007 on 39.2% incidence decrease was observed. Regionally the incidence varied from 142.3 in swietokrzyskie voivodeship to 1,830.6 in opolskie. Children and adolescents under 15 years of age accounted for 36% of all cases (age group incidence 1,415.6). In this age group the incidence varied regionally from 342.9 in swietokrzyskie voivodeship to 4,083.6 in opolskie. The highest reported incidence was observed in age group 0-4 years (1,545.6). 153 patients (0.07% of all cases) required hospital admission. There were 16 deaths due to influenza, of which 11 (68.8%) were among persons over 70 years of age. In the epidemic season 2007/08 infections with influenza virus registered in Poland were caused by type A (60% of laboratory confirmed influenza cases) as well as by type B (40% of laboratory confirmed influenza cases), similarly to other parts of Europe. Forty-four influenza strains were isolated, including 24 strains of subtype A/H1 and 20 strains of type B. All of them were antigenically similar to the vaccine strains recommended for the epidemic season 2007/2008.

Immunization against influenza during the 2005/2006 epidemic season and the humoral response in children with diagnosed inflammatory bowel disease (IBD).

BACKGROUND: Patients with inflammatory bowel disease (IBD) who are treated long-term with immunosuppressive drugs can experience a decrease in their overall resistance to infections, including influenza. The purpose of this study was to evaluate the humoral response in children with IBD after being vaccinated against influenza. MATERIAL/METHODS: Children with IBD were vaccinated with split inactivated vaccine. They were divided into 2 groups: children treated with anti-inflammatory medications and children treated with 5-acetylsalicylic acid along with immunomodulatory therapy. Antihemagglutinin (anti-HA) and antineuraminidase (anti-NA) antibodies were assessed before vaccination and 1 and 6 months after vaccination. RESULTS: Anti-HA and anti-NA antibodies 1 and 6 months after vaccination were higher than before vaccination. In the patients treated with anti-inflammatory medications, the protection rate (PR) attained the highest level for antigens A/H1N1 and B 6 months after vaccination. However, for A/H3N2 the result was 88.9% at 1 and 6 months after vaccination. In the patients who received immunomodulatory medications, the highest PR was noted 6 months after vaccination (47.6-90.5%). The response rate (RR) in patients who were treated with the anti-inflammatory medications alone remained the same 1 and 6 months after vaccination. In patients who received the immunomodulatory regimen, the highest RR was recorded 6 months after vaccination (47.6-76.2%). CONCLUSIONS: Response to vaccination was satisfactory, although not for all vaccine antigens, especially in patients treated with immunomodulatory medications. The higher levels of RP and RR 6 months after vaccination compared with 1 month after vaccination lends support to the argument that IBD patients should be vaccinated as soon as vaccine is available in a season.

[Influenza in Poland in 2007]. / Grypa w Polsce w 2007 roku.

A total number of 374,042 cases of influenza and influenza-like illness were registered in Poland in 2007 (incidence 981.3 per 100,000 population). Compared to 2006 on 48.6% incidence increase was observed. Despite this increase influenza activity in 2007 was among the lowest during the last four decades. Regionally the incidence varied from 182.2 in pomorskie voivodeship to 2,957.1 in opolskie. Children and adolescents under 15 years of age accounted for 33% of all cases (age specific incidence 2,098.3). In this age group the incidence varied regionally from 398.8 in pomorskie voivodeship to 5,908.3 in opolskie. The highest reported incidence was observed in age group 0-4 years (2,240.7). 763 patients (0.20% of all cases) required hospital admission. There were 18 deaths due to influenza, of which 17 (94.4%) were among persons over 70 years of age. In the epidemic season 2006/07 infections with influenza virus registered in Poland were mainly caused by type A, similarly to other parts of Europe. Seventeen influenza strains were isolated, including 12 strains of subtype A/H1 and 5 strains of subtype A/H3. All of them were antigenically similar to the vaccine strains recommended for the epidemic season 2006/07.

Antibody response to influenza vaccine in coronary artery disease: a substudy of the FLUCAD study.

BACKGROUND: Influenza vaccination is recommended for patients with cardiovascular diseases. The main reason for the low vaccination rates in such patients is insufficient knowledge about vaccination efficacy, including immune response to the vaccine. The aim of this study was to assess humoral response to influenza vaccination in patients with coronary artery disease. MATERIAL/METHODS: This was a substudy of the randomized prospective double-blind placebo-controlled FLUCAD study on influenza vaccination in the secondary prevention of ischemic coronary events in patients with coronary artery disease. Patients received inactivated subunit vaccine (n=325) or placebo (n=333). Anti-hemagglutinin and anti-neuraminidase antibody levels to the vaccine strains as well as IgM and IgG levels against influenza A and B were measured before administration of vaccine/placebo and after 8-10 weeks in 78 vaccinated and 97 placebo patients. RESULTS: Post-vaccination antibody titers were significantly higher than before vaccination, with mean increases of 4.9- to 5.7-fold for anti-hemagglutinin and 3.5- to 4.2-fold for neuraminidase antibodies. Post-vaccination protection rates ranged from 56.4 to 60.3% and response rates from 62.8 to 68%. The percentage of patients with significant post-vaccination concentrations of IgG and IgM was higher than before vaccination and amounted to 100% and 88.1% in the case of IgG and 14.3% and 5.2% in the case of IgM in response to influenza A and B, respectively. CONCLUSIONS: At least 60% of the patients achieved high post-vaccination antibody levels sufficient to prevent influenza.

Testing of human specimens for the presence of highly pathogenic zoonotic avian influenza virus A(H5N1) in Poland in 2006-2008 - justified or unnecessary steps?

Since 1997, human infections with highly pathogenic zoonotic avian influenza viruses have shown that the risk of influenza pandemic is significant. In Europe, infections caused by the highly pathogenic avian influenza A(H7N7) virus were confirmed in the human population in 2003 in the Netherlands. Moreover, outbreaks of A(H5N1) infections were observed in wild and farm birds in different European regions, including Poland in 2006-2008. This study presents 16 patients in Poland from whom clinical specimens were collected and tested for A(H5N1) highly pathogenic avian influenza. This article shows the results of laboratory tests and discusses the legitimacy of the collection and testing of the specimens. All patients were negative for A(H5N1) infection. Nevertheless, only two patients met clinical and epidemiological criteria from the avian influenza case definition. The conclusion is that there is still a strong necessity for increasing the awareness of medical and laboratory staff, as well as the awareness of some occupational groups about human infections with avian influenza viruses, including the importance of seasonal influenza vaccination. It should also be emphasized that in the case of patients suspected of being infected with avian influenza, the information about clinical symptoms is insufficient and must be accompanied by a wide epidemiological investigation.

Recombinant collagen studies link the severe conformational changes induced by osteogenesis imperfecta mutations to the disruption of a set of interchain salt bridges.

The clinical severity of Osteogenesis Imperfecta (OI), also known as the brittle bone disease, relates to the extent of conformational changes in the collagen triple helix induced by Gly substitution mutations. The lingering question is why Gly substitutions at different locations of collagen cause different disruptions of the triple helix. Here, we describe markedly different conformational changes of the triple helix induced by two Gly substitution mutations placed only 12 residues apart. The effects of the Gly substitutions were characterized using a recombinant collagen fragment modeling the 63-residue segment of the alpha1 chain of type I collagen containing no Hyp (residues 877-939) obtained from Escherichia coli. Two Gly --> Ser substitutions at Gly-901 and Gly-913 associated with, respectively, mild and severe OI variants were introduced by site-directed mutagenesis. Biophysical characterization and limited protease digestion experiments revealed that while the substitution at Gly-901 causes relatively minor destabilization of the triple helix, the substitution at Gly-913 induces large scale unfolding of an unstable region C-terminal to the mutation site. This extensive unfolding is caused by the intrinsic low stability of the C-terminal region of the helix and the mutation induced disruption of a set of salt bridges, which functions to lock this unstable region into the triple helical conformation. The extensive conformational changes associated with the loss of the salt bridges highlight the long range impact of the local interactions of triple helix and suggest a new mechanism by which OI mutations cause severe conformational damages in collagen.