Has a High Dose of Vitamin D3 Impacted Health Conditions in Older Adults?-A Systematic Review and Meta-Analysis Focusing on Dose 100,000 IU

BACKGROUND

Older adults are prone to vitamin D3 (VD3) deficiency, which may impair their health. A high dose of VD3 (HDVD3 = 100,000 IU) could improve their 25-hydroxyvitamin D3 [25(OH)D] level and health outcomes. However, evidence for such a beneficial effect of HDVD3 in older adults coming from clinical trials is mixed.

OBJECTIVE

To review the literature on the efficacy of a single dose of 100,000 IU of VD3 in older people.

METHODS

We searched PubMed/Medline, Science Direct, and NIH's clinical trials registry for clinical studies on the effect of a single high dose of VD3 on various health outcomes in older people. We also performed a meta-analysis using the standardized mean difference to assess the effect of VD3 on its blood level. Due to expected high heterogeneity, its amount (i.e., tau2) was estimated using the DerSimonian-Laird estimator. To estimate tau2, the Q-test for heterogeneity and the I2 statistic were calculated.

RESULTS

Search results identify 13 studies that reported diverse health outcomes, such as lung and cardiovascular function, skin cancer progression, intensive care unit mortality, immune system response, and bone density. The meta-analysis showed a significant increase in 25(OH)D blood levels after treatment in 10 studies, with an average standardized mean difference of 2.60 ng/mL (95% CI: 2.07 to 3.13). Their results suggested that a single high dose of VD3 may benefit intensive care unit patients and skin cancer patients in remission. However, evidence for other beneficial health effects of HDVD3 was mixed due to high heterogeneity among studies.

CONCLUSIONS

A single high dose of VD3 may positively affect some health outcomes in older people, possibly due to its pleiotropic and immunomodulatory effects. However, the evidence needs to be more extensive and consistent, and more rigorous studies are required to confirm the benefits and safety of VD3 high doses in older patients.

Evolution of the T4 phage virion is driven by selection pressure from non-bacterial factors

Bacteriophages colonize animal and human bodies, propagating on sensitive bacteria that are symbionts, commensals, or pathogens of animals and humans. T4-like phages are dependent on abundant symbionts such as Escherichia coli, commonly present in animal and human gastrointestinal (GI) tracts. Bacteriophage T4 is one of the most complex viruses, and its intricate structure, particularly the capsid head protecting the phage genome, likely contributes substantially to the overall phage fitness in diverse environments. We investigated how individual head proteins-gp24, Hoc, and Soc-affect T4 phage survival under pressure from non-bacterial factors. We constructed a panel of T4 phage variants defective in these structural proteins: T4∆Soc, T4∆24byp24, T4∆Hoc∆Soc, T4∆Hoc∆24byp24, T4∆Soc∆24byp24, and T4∆Hoc∆Soc∆24byp24 (byp = bypass). These variants were investigated for their sensitivity to selected environmental conditions relevant to the microenvironment of the GI tract, including pH, temperature, and digestive enzymes. The simple and "primitive" structure of the phage capsid (∆24byp24) was significantly less stable at low pH and more sensitive to inactivation by digestive enzymes, and the simultaneous lack of gp24 and Soc resulted in a notable decrease in phage activity at 37°C. Gp24 was also found to be highly resistant to thermal and chemical denaturation. Thus, gp24, which was acquired relatively late in evolution, seems to play a key role in T4 withstanding environmental conditions, including those related to the animal/human GI tract, and Soc is a molecular glue that enhances this protective effect. IMPORTANCE Bacteriophages are important components of animal and human microbiota, particularly in the gastrointestinal tract, where they dominate the viral community and contribute to shaping microbial balance. However, interactions with bacterial hosts are not the only element of the equation in phage survival-phages inhabiting the GI tract are constantly exposed to increased temperature, pH fluctuations, or digestive enzymes, which raises the question of whether and how the complex structure of phage capsids contributes to their persistence in the specific microenvironment of human/animal bodies. Here we address this phage-centric perspective, identifying the role of individual head proteins in T4 phage survival in GI tract conditions. The selection pressure driving the evolution of T4-like phages could have come from the external environment that affects phage virions with increased temperature and variable pH; it is possible that in the local microenvironment along the GI tract, the phage benefits from stability-protecting proteins.

Immunogenic epitope scanning in bacteriolytic enzymes Pal and Cpl-1 and engineering Pal to escape antibody responses

Bacteriolytic enzymes are promising antibacterial agents, but they can cause a typical immune response in vivo. In this study, we used a targeted modification method for two antibacterial endolysins, Pal and Cpl-1. We identified the key immunogenic amino acids, and designed and tested new, bacteriolytic variants with altered immunogenicity. One new variant of Pal (257-259 MKS → TFG) demonstrated decreased immunogenicity while a similar mutant (257-259 MKS → TFK) demonstrated increased immunogenicity. A third variant (280-282 DKP → GGA) demonstrated significantly increased antibacterial activity and it was not cross-neutralized by antibodies induced by the wild-type enzyme. We propose this variant as a new engineered endolysin with increased antibacterial activity that is capable of escaping cross-neutralization by antibodies induced by wild-type Pal. We show that efficient antibacterial enzymes that avoid cross-neutralization by IgG can be developed by epitope scanning, in silico design, and substitutions of identified key amino acids with a high rate of success. Importantly, this universal approach can be applied to many proteins beyond endolysins and has the potential for design of numerous biological drugs.

DNA Dye Sytox Green in Detection of Bacteriolytic Activity: High Speed, Precision and Sensitivity Demonstrated With Endolysins

Introduction: Increasing number of deaths from multi-drug resistant bacterial infections has caused both the World Health Organization and the Centers for Disease Control and Prevention to repeatedly call for development of new, non-traditional antibacterial treatments. Antimicrobial enzymes, including those derived from bacteriophages, known as endolysins or enzybiotics, are considered promising solutions among the emerging therapies. These naturally occurring proteins specifically destroy bacterial cell walls (peptidoglycan) and as such, are capable of killing several logs of bacteria within minutes. Some endolysins cause lysis of a wide range of susceptible bacteria, including both Gram-positive and Gram-negative organisms, whereas other endolysins are species- or even strain-specific. To make wide use of endolysins as antibacterial agents, some basic research issues remain to be clarified or addressed. Currently available methods for testing endolysin kinetics are indirect, require large numbers of bacteria, long incubation times and are affected by technical problems or limited reproducibility. Also, available methods are focused more on enzymatic activity rather than killing efficiency which is more relevant from a medical perspective.

Results: We show a novel application of a DNA dye, SYTOX Green. It can be applied in comprehensive, real-time and rapid measurement of killing efficiency, lytic activity, and susceptibility of a bacterial population to lytic enzymes. Use of DNA dyes shows improved reaction times, higher sensitivity in low concentrations of bacteria, and independence of bacterial growth. Our data show high precision in lytic activity and enzyme efficiency measurements. This solution opens the way to the development of new, high throughput, precise measurements and tests in variety of conditions, thus unlocking new possibilities in development of novel antimicrobials and analysis of bacterial samples.

Isolation and Characterization of Phages Active against Paenibacillus larvae Causing American Foulbrood in Honeybees in Poland

The aim of this study was the isolation and characterization, including the phage effect on honeybees in laboratory conditions, of phages active against Paenibacillus larvae, the causative agent of American Foulbrood-a highly infective and easily spreading disease occurring in honeybee larva, and subsequently the development of a preparation to prevent and treat this dangerous disease. From the tested material (over 2500 samples) 35 Paenibacillus spp. strains were obtained and used to search for phages. Five phages specific to Paenibacillus were isolated and characterized (ultrastructure, morphology, biological properties, storage stability, and genome sequence). The characteristics were performed to obtain knowledge of their lytic potential and compose the final phage cocktail with high antibacterial potential and intended use of future field application. Preliminary safety studies have also been carried out on healthy bees, which suggest that the phage preparation administered is harmless.

Immune Response to Therapeutic Staphylococcal Bacteriophages in Mammals: Kinetics of Induction, Immunogenic Structural Proteins, Natural and Induced Antibodies

Bacteriophages are able to affect the human immune system. Phage-specific antibodies are considered as major factors shaping phage pharmacokinetics and bioavailability. So far, general knowledge of phage antigenicity nevertheless remains extremely limited. Here we present comparative studies of immunogenicity in two therapeutic bacteriophages, A3R and 676Z, active against Staphylococcus aureus, routinely applied in patients at the Phage Therapy Unit, Poland. Comparison of the overall ability of whole phages to induce specific antibodies in a murine model revealed typical kinetics of IgM and IgG induction by these two phages. In further studies we identified the location of four phage proteins in the virions, with the focus on the external capsid head (Mcp) or tail sheath (TmpH) or an unidentified precise location (ORF059 and ORF096), and we confirmed their role as structural proteins of these viruses. Next, we compared the immune response elicited by these proteins after phage administration in mice. Similar to that in T4 phage, Mcp was the major element of the capsid that induced specific antibodies. Studies of protein-specific sera revealed that antibodies specific to ORF096 were able to neutralize antibacterial activity of the phages. In humans (population level), none of the studied proteins plays a particular role in the induction of specific antibodies; thus none potentially affects in a particular way the effectiveness of A3R and 676Z. Also in patients subjected to phage therapy, we did not observe increased specific immune responses to the investigated proteins.

Circulation of Fluorescently Labelled Phage in a Murine Model

Interactions between bacteriophages and mammals strongly affect possible applications of bacteriophages. This has created a need for tools that facilitate studies of phage circulation and deposition in tissues. Here, we propose red fluorescent protein (RFP)-labelled E. coli lytic phages as a new tool for the investigation of phage interactions with cells and tissues. The interaction of RFP-labelled phages with living eukaryotic cells (macrophages) was visualized after 20 min of co-incubation. RFP-labeled phages were applied in a murine model of phage circulation in vivo. Phages administered by three different routes (intravenously, orally, rectally) were detected through the course of time. The intravenous route of administration was the most efficient for phage delivery to multiple body compartments: 20 min after administration, virions were detected in lymph nodes, lungs, and liver; 30 min after administration, they were detectable in muscles; and 1 h after administration, phages were detected in spleen and lymph nodes. Oral and rectal administration of RFP-labelled phages allowed for their detection in the gastrointestinal (GI) tract only.

The effects of T4 and A5/80 phages on the expression of immunologically important genes in differentiated Caco-2 cells*

Introduction: Bacteriophages are an abundant component of the mucosal microbiota in humans and some animal species. Intestinal epithelial cells (IECs) are the key element responsible for the induction and regulation of immune responses in the gut mucosa. The objective of this study was to evaluate the effects of T4 and A5/80 bacteriophages on the expression of immunologically important genes in Caco-2, a model cell line for IECs. Materials & Method: Bacteriophages were added to cultures of differentiated Caco-2 cells for 12 hours, while control cultures were treated with phosphate-buffered saline (PBS). Expression of genes in Caco-2 cells was determined using custom-made RT2 Profiler PCR Arrays, which allow for the evaluation of gene expression with the sensitivity and specificity of real-time PCR. We evaluated the expression of 21 genes which are important for the immune functions of IECs, including IL1B, IL6, IL7, IL10, IL15, IL18, IL25, IL33, TGFB1, TNF, CXCL8, CCL2, TSLP, FCER2, PIGR, DEFB4A, CAMP, REG3G, TNFSF13, TNFSF13B, and MUC2. Results: Both examined phages significantly influenced the expression of a number of genes compared with control cultures. In particular, T4 significantly increased the expression of the CCL2 and DEFB4A genes, while A5/80 induced the expression of the PIGR gene. Discussion: Together with the findings from previous studies, our results suggest that by modulating the expression of some genes, bacteriophages may affect immune responses in the gut mucosa.

Phages in Therapy and Prophylaxis of American Foulbrood - Recent Implications From Practical Applications

American foulbrood is one of the most serious and yet unsolved problems of beekeeping around the world, because it causes a disease leading to the weakening of the vitality of honey bee populations and huge economic losses both in agriculture and horticulture. The etiological agent of this dangerous disease is an extremely pathogenic spore-forming bacterium, Paenibacillus larvae, which makes treatment very difficult. What is more, the use of antibiotics in the European Union is forbidden due to restrictions related to the prevention of the presence of antibiotic residues in honey, as well as the global problem of spreading antibiotic resistance in case of bacterial strains. The only available solution is burning of entire bee colonies, which results in large economic losses. Therefore, bacteriophages and their lytic enzymes can be a real effective alternative in the treatment and prevention of this Apis mellifera disease. In this review, we summarize phage characteristics that make them a potentially useful tool in the fight against American foulbrood. In addition, we gathered data regarding phage application that have been described so far, and attempted to show practical implications and possible limitations of their usage.

Induction of Phage-Specific Antibodies by Two Therapeutic Staphylococcal Bacteriophages Administered per os

In therapeutic phage applications oral administration is a common and well-accepted delivery route. Phages applied per os may elicit a specific humoral response, which may in turn affect phage activity. We present specific anti-phage antibody induction in mice receiving therapeutic staphylococcal bacteriophage A3R or 676Z in drinking water. The schedule comprised: (1) primary exposure to phages for 100 days, followed by (2) diet without phage for 120 days, and (3) secondary exposure to the same phage for 44 days. Both phages induced specific antibodies in blood (IgM, IgG, IgA), even though poor to ineffective translocation of the phages to blood was observed. IgM reached a maximum on day 22, IgG increased from day 22 until the end of the experiment. Specific IgA in the blood and in the gut were induced simultaneously within about 2 months; the IgA level gradually decreased when phage was removed from the diet. Importantly, phage-specific IgA was the limiting factor for phage activity in the gastrointestinal tract. Multicopy proteins (major capsid protein and tail morphogenetic protein H) contributed significantly to phage immunogenicity (IgG), while the baseplate protein gpORF096 did not induce a significant response. Microbiome composition assessment by next-generation sequencing (NGS) revealed that no important changes correlated with phage treatment.

The effects of bacteriophages on the expression of genes involved in antimicrobial immunity*

Introduction: Bacteriophages (viruses of bacteria) are used in the treatment of antibiotic‑resistant infections. Moreover, they are an important component of the mucosal microbiota. The objective of this study was to investigate the effects of T4 and A5/80 bacteriophages on the expression of genes involved in antimicrobial immunity, including Toll‑like receptors. Material/Methods: The expression of genes was determined in the A549 cell line using RT2 Profiler PCR Array. Results: Purified T4 and A5/80 phage preparations significantly affected the expression of 7 and 10 out of 84 examined genes, respectively. Discussion: Our results are important for phage therapy of bacterial infections and provide novel insights into the role of phages from the mucosal microbiota. They may also lead to novel applications of phages as antiviral and immunomodulatory agents.

Factors determining phage stability/activity: challenges in practical phage application

Introduction: Phages consist of nucleic acids and proteins that may lose their activity under different physico-chemical conditions. The production process of phage formulations may decrease phage infectivity. Ingredients present in the preparation may influence phage particles, although preparation and storage conditions may also cause variations in phage titer. Significant factors are the manner of phage application, the patient's immune system status, the type of medication being taken, and diet. Areas covered: We discuss factors determining phage activity and stability, which is relevant for the preparation and application of phage formulations with the highest therapeutic efficacy. Our article should be helpful for more insightful implementation of clinical trials, which could pave the way for successful phage therapy. Expert opinion: The number of naturally occurring phages is practically unlimited and phages vary in their susceptibility to external factors. Modern methods offer engineering techniques which should lead to enhanced precision in phage delivery and anti-bacterial activity. Recent data suggesting that phages may also be used in treating nonbacterial infections as well as anti-inflammatory and immunomodulatory agents add further weight to such studies. It may be anticipated that different phage activities could have varying susceptibility to factors determining their actions.

Bacteriophages engineered to display foreign peptides may become short-circulating phages

Bacteriophages draw scientific attention in medicine and biotechnology, including phage engineering, widely used to shape biological properties of bacteriophages. We developed engineered T4-derived bacteriophages presenting seven types of tissue-homing peptides. We evaluated phage accumulation in targeted tissues, spleen, liver and phage circulation in blood (in mice). Contrary to expectations, accumulation of engineered bacteriophages in targeted organs was not observed, but instead, three engineered phages achieved tissue titres up to 2 orders of magnitude lower than unmodified T4. This correlated with impaired survival of these phages in the circulation. Thus, engineering of T4 phage resulted in the short-circulating phage phenotype. We found that the complement system inactivated engineered phages significantly more strongly than unmodified T4, while no significant differences in phages' susceptibility to phagocytosis or immunogenicity were found. The short-circulating phage phenotype of the engineered phages suggests that natural phages, at least those propagating on commensal bacteria of animals and humans, are naturally optimized to escape rapid neutralization by the immune system. In this way, phages remain active for longer when inside mammalian bodies, thus increasing their chance of propagating on commensal bacteria. The effect of phage engineering on phage pharmacokinetics should be considered in phage design for medical purposes.

A Brief Reminder of Systems of Production and Chromatography-Based Recovery of Recombinant Protein Biopharmaceuticals

Recombinant proteins are produced for various applications in laboratory and industrial settings. Among them, therapeutic applications have evolved into a mature field in recent years, affecting the face of contemporary medical treatment. This, in turn, has stimulated an ever-greater need for innovative technologies for the description, expression, and purification of recombinant protein biopharmaceuticals. Therefore, many biopharmaceuticals are synthesized in heterologous systems to obtain satisfactory yields that cannot be provided by natural sources. As more than 35 years has passed since the first recombinant biopharmaceutical (human insulin) successfully completed clinical trials in humans, we provide a brief review of the available prokaryotic and eukaryotic expression systems, listing the advantages and disadvantages of their use. Some examples of therapeutic proteins expressed in heterologous hosts are also provided. Moreover, technologies for the universal extraction of protein molecules are mentioned here, as is the methodology of their purification.

Antibody Production in Response to Staphylococcal MS-1 Phage Cocktail in Patients Undergoing Phage Therapy

In this study, we investigated the humoral immune response (through the release of IgG, IgA, and IgM antiphage antibodies) to a staphylococcal phage cocktail in patients undergoing experimental phage therapy at the Phage Therapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, Poland. We also evaluated whether occurring antiphage antibodies had neutralizing properties toward applied phages (K rate). Among 20 examined patients receiving the MS-1 phage cocktail orally and/or locally, the majority did not show a noticeably higher level of antiphage antibodies in their sera during phage administration. Even in those individual cases with an increased immune response, mostly by induction of IgG and IgM, the presence of antiphage antibodies did not translate into unsatisfactory clinical results of phage therapy. On the other hand, a negative outcome of the treatment occurred in some patients who showed relatively weak production of antiphage antibodies before and during treatment. This may imply that possible induction of antiphage antibodies is not an obstacle to the implementation of phage therapy and support our assumption that the outcome of the phage treatment does not primarily depend on the appearance of antiphage antibodies in sera of patients during therapy. These conclusions are in line with our previous findings. The confirmation of this thesis is of great interest as regards the efficacy of phage therapy in humans.

Oral Application of T4 Phage Induces Weak Antibody Production in the Gut and in the Blood

A specific humoral response to bacteriophages may follow phage application for medical purposes, and it may further determine the success or failure of the approach itself. We present a long-term study of antibody induction in mice by T4 phage applied per os: 100 days of phage treatment followed by 112 days without the phage, and subsequent second application of phage up to day 240. Serum and gut antibodies (IgM, IgG, secretory IgA) were analyzed in relation to microbiological status of the animals. T4 phage applied orally induced anti-phage antibodies when the exposure was long enough (IgG day 36, IgA day 79); the effect was related to high dosage. Termination of phage treatment resulted in a decrease of IgA again to insignificant levels. Second administration of phage induces secretory IgA sooner than that induced by the first administrations. Increased IgA level antagonized gut transit of active phage. Phage resistant E. coli dominated gut flora very late, on day 92. Thus, the immunological response emerges as a major factor determining phage survival in the gut. Phage proteins Hoc and gp12 were identified as highly immunogenic. A low response to exemplary foreign antigens (from Ebola virus) presented on Hoc was observed, which suggests that phage platforms can be used in oral vaccine design.

Phage neutralization by sera of patients receiving phage therapy

The aim of our investigation was to verify whether phage therapy (PT) can induce antiphage antibodies. The antiphage activity was determined in sera from 122 patients from the Phage Therapy Unit in Wrocław with bacterial infections before and during PT, and in sera from 30 healthy volunteers using a neutralization test. Furthermore, levels of antiphage antibodies were investigated in sera of 19 patients receiving staphylococcal phages and sera of 20 healthy volunteers using enzyme-linked immunosorbent assay. The phages were administered orally, locally, orally/locally, intrarectally, or orally/intrarectally. The rate of phage inactivation (K) estimated the level of phages' neutralization by human sera. Low K rates were found in sera of healthy volunteers (K ≤ 1.73). Low K rates were detected before PT (K ≤ 1.64). High antiphage activity of sera K > 18 was observed in 12.3% of examined patients (n = 15) treated with phages locally (n = 13) or locally/orally (n = 2) from 15 to 60 days of PT. High K rates were found in patients treated with some Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis phages. Low K rates were observed during PT in sera of patients using phages orally (K ≤ 1.04). Increased inactivation of phages by sera of patients receiving PT decreased after therapy. These results suggest that the antiphage activity in patients' sera depends on the route of phage administration and phage type. The induction of antiphage activity of sera during or after PT does not exclude a favorable result of PT.

Bacteriophages displaying anticancer peptides in combined antibacterial and anticancer treatment

ABSTRACT: 

Aims: Novel anticancer strategies have employed bacteriophages as drug carriers and display platforms for anticancer agents; however, bacteriophage-based platforms maintain their natural antibacterial activity. This study provides the assessment of combined anticancer (engineered) and antibacterial (natural) phage activity in therapies. Materials & methods: An in vivo BALB/c mouse model of 4T1 tumor growth accompanied by surgical wound infection was applied. The wounds were located in the areas of tumors. Bacteriophages (T4) were modified with anticancer Tyr–Ile–Gly–Ser–Arg (YIGSR) peptides by phage display and injected intraperitoneally. Results & conclusion: Tumor growth was decreased in mice treated with YIGSR-displaying phages. The acuteness of wounds, bacterial load and inflammatory markers in phages-treated mice were markedly decreased. Thus, engineered bacteriophages combine antibacterial and anticancer activity.

Molecular imaging of T4 phage in mammalian tissues and cells

Advances in phage therapy encourage scientific interest in interactions of phages with human and animal organisms. This has created a need for developing tools that facilitate studies of phage circulation and deposition in tissues and cells. Here we propose a new green fluorescent protein (GFP)-based method for T4 phage molecular imaging in living systems. The method employs decoration of a phage capsid with GFP fused to the N-terminus of Hoc protein by in vivo phage display. Fluorescent phages were positively assessed as regards their applicability for detection inside living mammalian cells (by phagocytosis) and tissues (filtering and retention by lymph nodes and spleen). Molecular imaging provides innovative techniques that have brought substantial progress in life sciences. We propose it as a useful tool for studies of phage biology.

A novel approach for separating bacteriophages from other bacteriophages using affinity chromatography and phage display

Practical applications of bacteriophages in medicine and biotechnology induce a great need for technologies of phage purification. None of the popular methods offer solutions for separation of a phage from another similar phage. We used affinity chromatography combined with competitive phage display (i) to purify T4 bacteriophage from bacterial debris and (ii) to separate T4 from other contaminating bacteriophages. In ‘competitive phage display’ bacterial cells produced both wild types of the proteins (expression from the phage genome) and the protein fusions with affinity tags (expression from the expression vectors). Fusion proteins were competitively incorporated into the phage capsid. It allowed effective separation of T4 from a contaminating phage on standard affinity resins.

Recombinant expression and purification of T4 phage Hoc, Soc, gp23, gp24 proteins in native conformations with stability studies

Understanding the biological activity of bacteriophage particles is essential for rational design of bacteriophages with defined pharmacokinetic parameters and to identify the mechanisms of immunobiological activities demonstrated for some bacteriophages. This work requires highly purified preparations of the individual phage structural proteins, possessing native conformation that is essential for their reactivity, and free of incompatible biologically active substances such as bacterial lipopolysaccharide (LPS). In this study we describe expression in E. coli and purification of four proteins forming the surface of the bacteriophage T4 head: gp23, gp24, gphoc and gpsoc. We optimized protein expression using a set of chaperones for effective production of soluble proteins in their native conformations. The assistance of chaperones was critical for production of soluble gp23 (chaperone gp31 of T4 phage) and of gpsoc (chaperone TF of E. coli). Phage head proteins were purified in native conditions by affinity chromatography and size-exclusion chromatography. Two-step LPS removal allowed immunological purity grade with the average endotoxin activity less than 1 unit per ml of protein preparation. The secondary structure and stability of the proteins were studied using circular dichroism (CD) spectrometry, which confirmed that highly purified proteins preserve their native conformations. In increasing concentration of a denaturant (guanidine hydrochloride), protein stability was proved to increase as follows: gpsoc, gp23, gphoc. The denaturation profile of gp24 protein showed independent domain unfolding with the most stable larger domain. The native purified recombinant phage proteins obtained in this work were shown to be suitable for immunological experiments in vivo and in vitro.

Purification of phage display-modified bacteriophage T4 by affinity chromatography

BACKGROUND

Affinity chromatography is one of the most efficient protein purification strategies. This technique comprises a one-step procedure with a purification level in the order of several thousand-fold, adaptable for various proteins, differentiated in their size, shape, charge, and other properties. The aim of this work was to verify the possibility of applying affinity chromatography in bacteriophage purification, with the perspective of therapeutic purposes. T4 is a large, icosahedral phage that may serve as an efficient display platform for foreign peptides or proteins. Here we propose a new method of T4 phage purification by affinity chromatography after its modification with affinity tags (GST and Histag) by in vivo phage display. As any permanent introduction of extraneous DNA into a phage genome is strongly unfavourable for medical purposes, integration of foreign motifs with the phage genome was not applied. The phage was propagated in bacteria expressing fusions of the phage protein Hoc with affinity tags from bacterial plasmids, independently from the phage expression system.

RESULTS

Elution profiles of phages modified with the specific affinity motifs (compared to non-specific phages) document their binding to the affinity resins and effective elution with standard competitive agents. Non-specific binding was also observed, but was 102-105 times weaker than the specific one. GST-modified bacteriophages were also effectively released from glutathione Sepharose by proteolytic cleavage. The possibility of proteolytic release was designed at the stage of expression vector construction. Decrease in LPS content in phage preparations was dependent on the washing intensity; intensive washing resulted in preparations of 11-40 EU/ml.

CONCLUSIONS

Affinity tags can be successfully incorporated into the T4 phage capsid by the in vivo phage display technique and they strongly elevate bacteriophage affinity to a specific resin. Affinity chromatography can be considered as a new phage purification method, appropriate for further investigations and development.

The effect of bacteriophages T4 and HAP1 on in vitro melanoma migration

Background

The antibacterial activity of bacteriophages has been described rather well. However, knowledge about the direct interactions of bacteriophages with mammalian organisms and their other, i.e. non-antibacterial, activities in mammalian systems is quite scarce. It must be emphasised that bacteriophages are natural parasites of bacteria, which in turn are parasites or symbionts of mammals (including humans). Bacteriophages are constantly present in mammalian bodies and the environment in great amounts. On the other hand, the perspective of the possible use of bacteriophage preparations for antibacterial therapies in cancer patients generates a substantial need to investigate the effects of phages on cancer processes.

Results

In these studies the migration of human and mouse melanoma on fibronectin was inhibited by purified T4 and HAP1 bacteriophage preparations. The migration of human melanoma was also inhibited by the HAP1 phage preparation on matrigel. No response of either melanoma cell line to lipopolysaccharide was observed. Therefore the effect of the phage preparations cannot be attributed to lipopolysaccharide. No differences in the effects of T4 and HAP1 on melanoma migration were observed.

Conclusion

We believe that these observations are of importance for any further attempts to use bacteriophage preparations in antibacterial treatment. The risk of antibiotic-resistant hospital infections strongly affects cancer patients and these results suggest the possibility of beneficial phage treatment. We also believe that they will contribute to the general understanding of bacteriophage biology, as bacteriophages, extremely ubiquitous entities, are in permanent contact with human organisms.

[The influence of tobacco smoking on the state of dentition and the effect of the chronic periodontitis conservative treatment in periodontology clinic patients at the Chair and Department of Periodontology of the Medical University in Lublin]

Tobacco smoking is a serious health and social problem. The aim of the study was investigation of the influence of tobacco smoking on the state of dentition and effects of conservative treatment of the chronic, moderately advanced periodontitis by comparison of API, SBI, PPD and CAL indices before and after the treatment in smoking and non-smoking patients. Smokers group consisted of 30 people aged 30-48 including 15 men and 15 women who had smoked for more than 10 years, with the intensity of smoking of more than 10 cigarettes a day. The control group constituted 30 non-smoking people aged 30-50; 15 men and 15 women. The SBI index of bleeding from periodontal pockets in smokers is essentially statistically lower than in non-smokers, with similar hygiene indices. Shallowing of periodontal pockets depth (PPD) after the treatment is smaller than in smokers. Reconstruction of alveolodental ligament measured with CAL index in smokers seems to be smaller than in non-smokers.

Comparison of the effectiveness of the conservative treatment of the periodontal pockets with or without the use of laser biostimulation

The use of laser therapy as the agent reinforcing conventional treatment of the periodontal diseases becomes more and more common. In the physiotherapy of the periodontal diseases the biostimulating, laser is eagerly used because of its action which accelerates the healing of wounds and also because of its antioedematous, anti-inflammatory and analgesic action. The aim of work was the evaluation of the influence of laser biostimulation on the change of the periodontological pockets depth after the routine conservative periodontological treatment with additional use of laser biostimulation and without it for two groups of pockets: above and below 5 mm. In six patients having periodontitis 613 sites were submitted to the statistic analysis (290 treated conservatively only, including 251 with the depth 2-5 mm and 39 above 5 mm as well as 323 with the use of laser therapy including 297 shallow pockets and 26 deep ones). The initial values of API, SBI, PPD and their changes in the course of the treatment were registered. During each control appointment the patients subjectively estimated periodontal pain occurrence. In both studied groups statistically essential decrease of the evaluated parameters was obtained. Reinforcing the conventional treatment with laser biostimulation shortens its duration and leads to the elimination of pain faster than with the use of conservative treatment only. The changes of the PPD index among the successive examinations were statistically essentially higher in the therapy with the use of laser, especially in relation to deep pockets.

The application of Bio-Oss and Bio-Gide as implant materials in the complex treatment of aggressive periodontitis

In the presented study the results of the complex conservative and surgical periodontological treatment using Bio-Oss implant material and the regenerative Bio-Gide collagen membrane by Geistlich company were subjected to clinical and radiological evaluation. The measure depth of the periodontal pockets PPD was subjected to evaluation, the level of the epithelial attachment CAL and the defect of bone of the alveolar process were observed on radiograms. In all patients the state of oral cavity hygiene was examined using the index of API bacterial plaque and the percent of SBI index of bleeding gingiva. The analysis of the examined parameters concerned the period before surgeries and 8 to 12 months after the surgeries of the guided tissue regeneration. On the basis of the conducted research and the statistic analysis, the reduction of the periodontal pockets depth and the reconstruction of the attachment.

Use of Emdogain enamel matrix proteins in the surgical treatment of aggressive periodontitis

One of the ways of treating of the aggressive forms of periodontitis is the method of guided tissue regeneration using enamel matrix proteins included in Emdogain preparation. The aim of work was clinical evaluation of the complex treatment of those periodontolyses using the above mentioned material as the implant material. 35 intrabony pockets were operated in 11 patients aged 17-50. The treatment results were described with the use of clinical indices of API and SBI, indices of pockets depth PPD and the loss of the attachment CAL indices before and within the period of 8 to 12 months after the surgeries. The values of the examined features were submitted to statistical analysis using Shapiro-Wilks and Wilcoxon's tests. The treatment that was applied led to extremely statistically significant improvement of the examined parameters.

The use of HA-Biocer in the complex treatment of aggressive periodontal diseases

The aim of the work was clinical and radiological evaluation of the HA-Biocer implant material in the complex conservative and surgical treatment of the advanced changes in marginal periodontium. Highly statistically important reduction of the attachment loss CAL and pockets depth PPD were obtained.

Prefrontal cortex 5-HT2 receptors in depression: an [18F]setoperone PET imaging study

OBJECTIVE

Widespread disturbances of serotonin (5-HT) are implicated in the pathophysiology of depression. Of 5-HT receptor abnormalities reported, the most replicated finding is increased 5-HT2 receptor binding in the postmortem prefrontal cortex of depressed suicide victims. The extent to which these findings exist in depressed persons without recent suicide attempts is uncertain. The objective of this study was to evaluate 5-HT2 receptors in depressed patients who were medication-free and who had not made recent suicide attempts.

METHOD

With the use of [18F]setoperone and positron emission tomography (PET), 5-HT2 receptor binding potential was assessed in 14 depressed and 19 healthy subjects. Exclusion criteria for depressed patients included use of antidepressant medication within the past 6 months, a history of suicide attempts within the past 5 years, other current axis I disorders including bipolar disorder, and the presence of psychotic symptoms. The 5-HT2 (setoperone) binding potential in the two groups of subjects was compared by analysis of covariance with age as the covariate.

RESULTS

Age had a significant effect on 5-HT2 binding potential, but depression did not. The interaction of age and depression was not significant.

CONCLUSIONS

The 5-HT2 binding potential is not increased in untreated depressed subjects who have not made recent suicide attempts. This negative finding does not rule out the possibility that there is a role for 5-HT2 receptors in treatment or that 5-HT2 receptors are increased in highly suicidal states.

[Incidence of parodontal diseases in workers of the Chełm Cement Plant exposed to cement dust]

The purpose of the study was evaluation of the incidence of parodontal diseases in workers exposed in their occupation to cement dust. Stomatological examinations were carried out in 127 workers of the plant (98 men and 29 women) aged 18 to 64 years. The control group comprised 117 persons (58 men and 59 women) aged 22 to 66 years. The condition of the parodontium was assessed and classified according to a 3-grade scoring system used for parodontal disease assessment. The obtained data were subjected to statistical and lysis. The intensity of the parodontal disease was greater in workers exposed to cement dust than in controls, and a very high incidence of deep parodontitis was noted in young workers in the plant.