Injectable Platelet-Rich Fibrin as a Drug Carrier Increases the Antibacterial Susceptibility of Antibiotic—Clindamycin Phosphate

The aim of this study was to investigate the change in clindamycin phosphate antibacterial properties against Gram-positive bacteria using the platelet-rich fibrin as a carrier matrix, and evaluate the changes in the antibiotic within the matrix. The antibacterial properties of CLP and its combination with PRF were tested in a microdilution test against reference cultures and clinical isolates of Staphylococcus aureus (S. aureus) or Staphylococcus epidermidis (S. epidermidis). Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analysis was done to evaluate the changes in the PRF_CLP matrix. Release kinetics of CLP was defined with ultra-performance liquid chromatography (UPLC). According to FTIR data, the use of PRF as a carrier for CLP ensured the structural changes in the CLP toward a more active form of clindamycin. A significant decrease in minimal bactericidal concentration values (from 1000 µg/mL to 62 µg/mL) against reference cultures and clinical isolates of S. aureus and S. epidermidis was observed for the CLP and PRF samples if compared to pure CLP solution. In vitro cell viability tests showed that PRF and PRF with CLP have higher cell viability than 70% after 24 h and 48 h time points. This article indicates that CLP in combination with PRF showed higher antibacterial activity against S. aureus and S. epidermidis compared to pure CLP solution. This modified PRF could be used as a novel method to increase drug delivery and efficacy, and to reduce the risk of postoperative infection.     

From Blood to Regenerative Tissue: How Autologous Platelet-Rich Fibrin Can Be Combined with Other Materials to Ensure Controlled Drug and Growth Factor Release

The purpose of this review is to examine the latest literature on the use of autologous platelet-rich fibrin as a drug and growth factor carrier system in maxillofacial surgery. Autologous platelet-rich fibrin (PRF) is a unique system that combines properties such as biocompatibility and biodegradability, in addition to containing growth factors and peptides that provide tissue regeneration. This opens up new horizons for the use of all beneficial ingredients in the blood sample for biomedical purposes. By itself, PRF has an unstable effect on osteogenesis: therefore, advanced approaches, including the combination of PRF with materials or drugs, are of great interest in clinics. The main advantage of drug delivery systems is that by controlling drug release, high drug concentrations locally and fewer side effects within other tissue can be achieved. This is especially important in tissues with limited blood supply, such as bone tissue compared to soft tissue. The ability of PRF to degrade naturally is considered an advantage for its use as a “warehouse” of controlled drug release systems. We are focusing on this concentrate, as it is easy to use in manipulations and can be delivered directly to the surgical site. The target audience for this review are researchers and medical doctors who are involved in the development and research of PRFs further studies. Likewise, surgeons who use PRF in their work to treat patients and who advice patients to take the medicine orally.     

Functional granulocyte/macrophage colony stimulating factor receptor is constitutively expressed on neoplastic plasma cells and mediates tumour cell longevity

The effects of various drugs were assessed in rats responding under a Differential-Reinforcement-of-Low-Rate 30-s (DRL 30-s) schedule. Atropine, scopolamine, and CEB-1957 (a new muscarinic blocker) increased response rate and decreased reinforcement rate, while methylatropine only decreased reinforcement rate. Physostigmine decreased response and reinforcement rates, when pyridostigmine had few effect on DRL responding. The irreversible acetylcholinesterase (AChE) inhibitors organophosphorus compounds (OPC) soman and sarin, injected at one-third of the LD50 did not consistently alter DRL performance, suggesting that they produce few behavioral effects in the rat when administered at subtoxic doses. Three oximes--pralidoxime, pyrimidoxime, and HI-6--decreased both response and reinforcement rates. Mecamylamine had few consistent effects on performance, and nicotine, d-amphetamine, diazepam, and the wakening drug modafinil increased response rate and decreased reinforcement rate. These two latter drugs also increased the number of very premature responses. These results, taken together, indicate that a DRL schedule is a useful tool to bring to light the existence of psychotropic effects of a drug. The explanation of drug-induced alterations of DRL performance, in terms of effects on cognition or on mood, is also discussed.     

Selective Intramolecular Palladium(II)‐Catalyzed Aminooxygenation vs. Diamination of Alkenylureas: Efficient Microwave‐Assisted Reactions to Bicyclic Piperazinones

Alkenylureas arising from glycine allylamides were proven to be suitable substrates for the synthesis of bicyclic five‐membered ring‐fused piperazinones. The reported intramolecular domino processes, performed under oxidative conditions with bis(acetonitrile)palladium dichloride as catalyst and copper(II) chloride in a stoichiometric amount by microwave activation, were completely selective, involving either diamination or aminooxygenation. While the latter process is determined by the direct intervention of the urea oxygen on the σ‐alkylpalladium intermediate, the diamination reaction can in principle derive from a direct attack of the second nitrogen atom on the palladium complex or on the first formed chloromethylpiperazinone. Indeed, this latter species was isolated and proved to be capable of conversion solely into the imidazopiperazinone.     

Charge-transporting 3,4-ethylenedioxythiophene-based hydrazone monomers and oligomers

3,4-Ethylenedioxythiophene-based hydrazones, containing reactive functional groups were synthesized and their optical, thermal, photophysical and electrochemical properties were studied. The monomers were subjected to cationic polymerization using boron trifluoride etherate as an initiator. The ionization potentials of the films of the hydrazones, measured by the electron photoemission technique, range from 5.53 to 5.62 eV. Room temperature time-of-flight hole mobilities in the solid solutions of 3,4-ethylenedioxythiophene hydrazone monomers in bisphenol-Z polycarbonate exceed 10^?5 cm² V^?1 s^?1 at high applied electric fields.     

2',2'-Difluorodeoxycytidine (gemcitabine) induces apoptosis in myeloma cell lines resistant to steroids and 2-chlorodeoxyadenosine (2-CdA)

The paucity of effective cytotoxic agents for the treatment of steroid resistant multiple myeloma explains the ongoing search for alternative substances for chemotherapy of this disease. In the present study, the purine antagonist 2-chlorodeoxyadenosine (2-CdA, cladribine) and the pyrimidine antagonist 2',2'-difluorodeoxycytidine (gemcitabine) were tested on four myeloma cell lines (i.e., U 266, OPM 2, RPMI 8226, IM 9), one plasma cell leukemia cell line (HS Sultan) and a myeloid control cell line (HL 60), all of which are resistant to 10-6 M dexamethasone. Gemcitabine has been found to be promising in the chemotherapy of other tumors with low proliferative activity, but its effectiveness against myeloma cells has not been analyzed so far. In our tests, gemcitabine induced a significant degree of apoptosis in all cell lines investigated. After incubation for 48 h with 10 microM gemcitabine, the median numbers of apoptotic cells were in the range of 45% in the OPM 2 and 79% in the U 266 cell line. All of the investigated cell lines were responsive to concentrations of 10 microM gemcitabine even after an exposure of only 30 min, three of them (U 266, HS Sultan, IM 9) also responded to a concentration of 10 nM. Higher concentrations and longer exposure times were necessary to suppress the growth of normal hematopoietic bone marrow progenitor cells. In contrast to gemcitabine, standard concentrations of 2-CdA (i.e., 30 and 300 nM) failed to induce a significant degree of apoptosis in the cell lines investigated but inhibited the growth of myeloid progenitor cells. The results suggest that gemcitabine induces apoptosis in myeloma and plasma cell leukemia lines resistant to steroids and 2-CdA. The fact that tumor cell apoptosis was achieved at concentrations clinically achievable and tolerable, which at the same time do not inhibit the growth of normal CFU-GM progenitor cells, favors the initiation of phase I trials with this drug for the treatment of multiple myeloma.     

Additive Manufacturing of SiOC,SiC, and Si3N4 Ceramic 3D Microstructures

Herein, the fabrication of hard ceramic SiOC 3D microstructures by precursor synthesis, laser lithography, and pyrolysis combination is proposed. Precursors are hybrid organosilicon materials prepared via sol–gel method using trimethoxymethylsilane and 3-(trimethoxysilyl)propyl methacrylate, which has an acrylate functional group enabling laser photopolymerization process. Hard 3D ceramic structures (hardness up to ≈15 GPa, reduced elastic modulus ≈105 GPa) from soft organometallic derivatives are obtained after high-temperature pyrolysis under nitrogen atmosphere. The advantage of the proposed method is the absence of shrinkage defects leading to a uniform repetitive decrease in the volume of printed microstructures. In contrast to slurry-based printing technology, the proposed method is focused on homogeneous monolithic molecular resins resulting in visual smooth surfaces of prepared microstructures. Moreover, the printing resolution of the proposed method is substantially improved through the absence of predispersed ceramic microparticles in mixtures, which is a necessary element in a slurry-based technology.     

Optimisation of X-ray examinations in Lithuania: start of implementation in mammography

Optimisation of medical X-ray examinations is very important for the enhancement of the reliability of the examination and for the reduction of the radiation dose to patients. Results of investigations of doses to patients during mammography using thermoluminescence dosemeters at different hospitals are presented together with a brief overview of the situation for mammography in Lithuania. It is shown that the entrance surface air kerma varies in a broad range and differed from hospital to hospital. Nevertheless the calculated values of average glandular dose (AGD) for a 'standard' breast being relatively high were comparable with those (3.2 mGy per exposure at net optical density 1.4) currently accepted by international authorities. Differences in AGD values evaluated at different hospitals demonstrate the existing potential for optimisation of the mammography screening procedures. The results of this investigation will be included in a database for patient doses in Lithuania and used for establishing a national reference dose level for mammography. Currently, reference levels recommended by international authorities are used in Lithuania.     

Technology and characterisation of whole hemp seed beverages prepared from ultrasonicated and fermented whole seed paste

The aim of this study was to apply fermentation with Pediococcus acidilactici LUHS29, P. pentosaceus LUHS183, Lactobacillus casei LUHS210 and L. uvarum LUHS245 strains, as well as ultrasonication (US) for whole hemp (Cannabis sativa L.) seed paste (HSP) treatment and preparation of emulsions (HSE). Additionally, the biogenic amine (BA) content and antimicrobial properties of the prepared products were evaluated. It was found that US and fermentation reduced total bacteria count in HSP. The highest BA content was found in US-treated HSP (639.87 mg kg⁻¹). HSE_US, HSE_LUHS29, HSE_LUHS183, HSE_LUHS210 and HSE_LUHS245 samples showed lower ζ-potential. The highest overall acceptability (OA) was established for HSE_LUHS245, and correlations were established between the emotions induced by the different HSE products and OA. Pure LAB showed a broad variety of pathogen inhibition; however, the antimicrobial activity of HSP was very low, and HSE did not show any antimicrobial properties. Finally, treatment with selected LAB can be recommended for preparation of stable emulsions, and the most acceptable beverages can be obtained by using LUHS245 strain.