Creation of a 3D Goethite-Spongin Composite Using an Extreme Biomimetics Approach

The structural biopolymer spongin in the form of a 3D scaffold resembles in shape and size numerous species of industrially useful marine keratosan demosponges. Due to the large-scale aquaculture of these sponges worldwide, it represents a unique renewable source of biological material, which has already been successfully applied in biomedicine and bioinspired materials science. In the present study, spongin from the demosponge Hippospongia communis was used as a microporous template for the development of a new 3D composite containing goethite [α-FeO(OH)]. For this purpose, an extreme biomimetic technique using iron powder, crystalline iodine, and fibrous spongin was applied under laboratory conditions for the first time. The product was characterized using SEM and digital light microscopy, infrared and Raman spectroscopy, XRD, thermogravimetry (TG/DTG), and confocal micro X-ray fluorescence spectroscopy (CMXRF). A potential application of the obtained goethite-spongin composite in the electrochemical sensing of dopamine (DA) in human urine samples was investigated, with satisfactory recoveries (96% to 116%) being obtained.

Spongin as a Unique 3D Template for the Development of Functional Iron-Based Composites Using Biomimetic Approach In Vitro

Marine sponges of the subclass Keratosa originated on our planet about 900 million years ago and represent evolutionarily ancient and hierarchically structured biological materials. One of them, proteinaceous spongin, is responsible for the formation of 3D structured fibrous skeletons and remains enigmatic with complex chemistry. The objective of this study was to investigate the interaction of spongin with iron ions in a marine environment due to biocorrosion, leading to the occurrence of lepidocrocite. For this purpose, a biomimetic approach for the development of a new lepidocrocite-containing 3D spongin scaffold under laboratory conditions at 24 °C using artificial seawater and iron is described for the first time. This method helps to obtain a new composite as "Iron-Spongin", which was characterized by infrared spectroscopy and thermogravimetry. Furthermore, sophisticated techniques such as X-ray fluorescence, microscope technique, and X-Ray diffraction were used to determine the structure. This research proposed a corresponding mechanism of lepidocrocite formation, which may be connected with the spongin amino acids functional groups. Moreover, the potential application of the biocomposite as an electrochemical dopamine sensor is proposed. The conducted research not only shows the mechanism or sensor properties of "Iron-spongin" but also opens the door to other applications of these multifunctional materials.

The Loss of Structural Integrity of 3D Chitin Scaffolds from Aplysina aerophoba Marine Demosponge after Treatment with LiOH

Aminopolysaccharide chitin is one of the main structural biopolymers in sponges that is responsible for the mechanical stability of their unique 3D-structured microfibrous and porous skeletons. Chitin in representatives of exclusively marine Verongiida demosponges exists in the form of biocomposite-based scaffolds chemically bounded with biominerals, lipids, proteins, and bromotyrosines. Treatment with alkalis remains one of the classical approaches to isolate pure chitin from the sponge skeleton. For the first time, we carried out extraction of multilayered, tube-like chitin from skeletons of cultivated Aplysina aerophoba demosponge using 1% LiOH solution at 65 °C following sonication. Surprisingly, this approach leads not only to the isolation of chitinous scaffolds but also to their dissolution and the formation of amorphous-like matter. Simultaneously, isofistularin-containing extracts have been obtained. Due to the absence of any changes between the chitin standard derived from arthropods and the sponge-derived chitin treated with LiOH under the same experimental conditions, we suggest that bromotyrosines in A. aerophoba sponge represent the target for lithium ion activity with respect to the formation of LiBr. This compound, however, is a well-recognized solubilizing reagent of diverse biopolymers including cellulose and chitosan. We propose a possible dissolution mechanism of this very special kind of sponge chitin.

Liquid Storage of Hematopoietic Stem Cells Versus Proliferative Potential Colony-Forming Unit Granulocyte-Monocytes: Validation of Cell Processing

BACKGROUND

The material for transplantation must be of the highest quality. As far as we know, short-term storage is one of the crucial points of stem cell banking. According to the quality assurance system in a stem cell bank, each step of cell processing must be validated. The aim of this study was to assess the influence of short-term storage conditions into a clonogenic assay.

METHODS

Material was collected from mobilized peripheral blood by means of leukapheresis from 15 patients. Samples were stored at 4°C and 20°C; samples were evaluated on the day of leukapheresis and after 24 hours and after 48 hours of storage. The number of colony-forming unit granulocyte-monocyte (CFU-GM) precursors was analyzed with the use of in vitro culture. The material was evaluated before freezing and after thawing.

RESULTS

The average number of CFU-GM precursors in the material stored at 4°C before freezing on the day of collection was 84/10(5) nuclear cells (nc) and after 24 hours and 48 hours of storage was, respectively, 62/10(5) nc (P = .011719) and 36/10(5) nc (P = .02088). The average of the CFU-GM precursors in material stored at 20°C after 24 hours and 48 hours of storage amounted to 33/10(5) nc (P = .004439) and 2/10(5) nc (P = .00346), respectively.

CONCLUSIONS

In our study, the number of colonies of CFU-GM after 24 hours and 48 hours of storage, both at 4°C and 20°C, was significantly reduced compared with the number of colonies on the day of collection. Significantly greater numbers of CFU-GM precursors were observed in the material stored before freezing at 4°C in comparison with the material stored at 20°C.

Banking of Hematopoietic Stem Cells: Influence of Storage Time on Their Quality Parameters

BACKGROUND

Banking of hematopoietic stem cells (HSCs) is a rapidly growing part of the transplant field. The essence of the banking process is to maintain the optimal quality parameters throughout the storage period, allowing successful transplantation.

METHODS

Our laboratory research was carried out on 126 HSC samples that were collected by means of leukapheresis from patients with lymphoproliferative diseases. The samples were frozen in a controlled rate and stored up to 76 months in containers in vapor phase of liquid nitrogen. The evaluation was performed after thawing the probes. Viability of nuclear cells was assessed after incubation in Trypan blue, CD34+ phenotype cells were determined by means of cytometry with the use of 7-aminoactinomycin D (7-AAD), and an analysis of the proliferative potential of granulocyte-monocyte precursors was performed. For comparative statistical analysis, the material was divided into 3 groups according to storage time: A: <1 month (n = 45); B: 1-12 months (n = 50); C: >12 months (n = 31).

RESULTS

In the examined groups, similar median values were observed of nuclear cell viability (A, 86%; B, 87%; and C, 83%) and CD34+ cells (95%, 94.5%, and 95.8%, respectively). A gradual, nonsignificant, reduction in the median of granulocyte-monocyte precursors was found: 68 × 10(4)/kg of body weight (kg bw), 48.5 × 10(4)/kg bw, and 47 × 10(4)/kg bw, respectively. Statistical analysis with the use of the Kruskal-Wallis test showed a P value of >.05 for all variables.

CONCLUSIONS

There were no significant differences in the viability of nuclear cells, CD34+ cells, and proliferative potential granulocyte-monocyte precursors between groups. Storage for up to 76 months does not change the essential quality parameters, and HSCs could be qualified for distribution.

Analysis of the effect of cryoprotectant medium composition to viability of autologous hematopoietic cells collected by leukapheresis

OBJECTIVES

Cryopreservation of hematopoietic stem cells intended for autologous transplantation is a crucial element of the banking process. Although cryopreservation techniques are well known, improvement is needed. This study was designed to optimize cryopreservation to improve the quantitative and qualitative parameters of hematopoietic stem cells in the material intended for transplantation. We used available opportunities to provide the best quantitative and qualitative parameters of hematopoietic stem cell transplants processed in a closed system.

MATERIAL AND METHODS

Two hundred forty-eight products of hematopoietic stem cells collected by leukapheresis from patients with lymphoproliferative disorders create the basis of this report. The material was frozen in a controlled-rate freezer and stored in containers in the vapor phase of LN2 (-160°C). The composition of a cryoprotectant medium was modified. For freezing, 192 probes were used with a cryoprotective medium containing 20% dimethyl sulfoxide (DMSO) and enriched RPMI 1640. For 56 samples, we used 20% DMSO in autologous plasma harvested during leukapheresis. Products of hematopoietic stem cells and cryoprotectant medium were combined in a 1:1 ratio. The final number of nuclear cells did not exceed 2 × 10(8)/mL. Analysis was performed after thawing the probes. Viability of nuclear cells has been assessed using the microscopic technique after incubation in Trypan blue and the CD34+ cells by flow cytometry using the 7-aminoactynomycin D. A statistical analysis has been conducted using the Statistica program (StatSoft, Cracow, Poland).

RESULTS AND CONCLUSIONS

The results show that the application of autologous plasma is linked with higher viability of nuclear cells and CD34+ cells. Moreover, statistical analysis of the nuclear cells and CD34+ cells viability differs significantly between groups frozen using RPMI 1640 and autologous plasma (P < .05). To assess the viability of CD34+, cells frozen using RPMI 1640 results showed a large span of at 16.4% to 99.1% living cells.

Three-dimensional positioning of B chromosomes in fibroblast nuclei of the red fox and the chinese raccoon dog

Great progress has been achieved over the last years in studies on chromosome arrangement in mammalian cell nuclei. Growing evidence indicates that the genome's spatial organization is of functional relevance. So far, no attention has been paid to the nuclear organization of B chromosomes (Bs). In this study we have examined nuclear positioning of Bs in 2 species from the Canidae family--the red fox and the Chinese raccoon dog. Using 2D and 3D fluorescence in situ hybridization and 2 gene-specific probes (C-KIT and PDGFRA), we analyzed the location of Bs in fibroblast nuclei. We found that small Bs of the red fox occupied mostly the interior of the nucleus, while medium-sized Bs of the Chinese raccoon dog were observed in the peripheral area of the nucleus as well as in intermediate and interior locations. The more uniform distribution of B chromosomes in the Chinese raccoon dog may be the result of differences in their size, since 3 morphological types of Bs are distinguished in this species. Our results indicate that 3D positioning of B chromosomes in fibroblast nuclei of the 2 canid species is in agreement with the chromosome size-dependent theory.

Can von Willebrand factor, platelet-endothelial cell adhesion molecule-1 and thrombomodulin be used as alternative markers of endothelial cell injury in human glomerulonephritis?

PURPOSE

There is growing evidence that endothelial cells (EC) are active participants of an inflammatory process in glomeruli.

MATERIAL AND METHODS

We compared the glomerular expression of three EC-coupled molecules, i.e. platelet-endothelial cell adhesion molecule-1 (PECAM-1 or CD31), von Willebrand factor (vWF) and thrombomodulin (TM) in 60 patients with glomerulonephritis (GN) and five normal kidneys (NK). The alkaline phosphatase anti-alkaline phosphatase method was used to examine the expression of these proteins in the biopsy specimens.

RESULTS

In NK, the expression of CD31 and vWF comprised the whole glomerular network. In contrast, the expression of TM was much lower and localized mainly to EC at the vascular pole and adjacent areas. In GN, the glomerular staining for CD31 and vWF was significantly reduced. A fall in the expression of both these EC antigens was more pronounced in proliferative forms of GN (PGN) than in non-proliferative GN (NPGN) (CD31: NPGN vs. PGN, p < 0.02; vWF: NPGN vs. PGN, p < 0.05). In addition, a linear relationship between the expression of CD31 and vWF was found in GN (r = 0.8, p < 0.001). Conversely to CD31 and vWF, a marked increase in glomerular reactivity for TM was observed in all the patients with GN (GN: 2.12 +/- 0.32, NK: 0.95 +/- 0.05, p < 0.02). However, the highest expression of TM was found in membranoproliferative GN and lupus GN.

CONCLUSIONS

Our results suggest that CD31 and vWF may be used as markers of glomerular EC loss during GN, whereas TM staining seems to reflect EC activation in response to circulating and/or released in situ procoagulant factors.

Expression of two alternative transcription forms of platelet-derived growth factor-A chain in the normal human kidney and in glomerulonephritis

PURPOSE

Up to now, a role of platelet-derived growth factor (PDGF)-AA in glomerulonephritis (GN) remains unclear. PDGF-A chain may be produced in two forms, as a result of the alternative splicing.

MATERIAL AND METHODS

We examined the expression of this growth factor in the renal tissue of 57 patients with GN and seven normal kidneys (NK). The gene expression of PDGF-A was examined by reverse transcriptase-polymerase chain reaction. Sets of primers allowing distinction between the two forms of transcripts were used. Specificity of the PCR products was confirmed by restriction enzyme analysis and sequencing. The expression of PDGF-AA/AB was also evaluated by immunohistochemistry.

RESULTS

Compared to NK, the expression of PDGF-A gene was higher in the renal tissue with GN. This expression was higher in non-proliferative GN (NPGN) than in proliferative forms of GN (PGN) (1.24 +/- 0.34 vs. 0.86 +/- 0.14). In NK, both forms of transcripts (N = 4) or only the short one (N = 3) were found. In 45.5% of patients with NPGN, only the short form could be detected. In contrast, in 68.6% of patients with PGN both or only the longer form of transcripts were found. In NK, a faint staining for PDGF-AA/AB was observed within glomerular capillaries, whereas a statistically significant increase in this protein expression was particularly stated in NPGN. These results suggest that the production of the longer PDGF-A chain variant is associated with glomerular cells' proliferation. However, the higher expression of PDGF-AA/AB protein in NPGN could indicate an essential role of this growth factor in the maintaining the glomerular architecture.