Lajos Kolozsvári

Femtosecond laser printing of living cells using absorbing film-assisted laser-induced forward transfer

The applicability of a femtosecond KrF laser in absorbing film-assisted, laser-induced forward transfer of living cells was studied. The absorbing materials were 50-nm-thick metal films and biomaterials (gelatine, Matrigel, each 50 μm thick, and polyhydroxybutyrate, 2 μm). The used cell types were human neuroblastoma, chronic myeloid leukemia, and osteogenic sarcoma cell lines, and primary astroglial rat cells. Pulses of a 500-fs KrF excimer laser focused onto the absorbing layer in a 250-μm diameter spot with 225  mJ/cm2 fluence were used to transfer the cells to the acceptor plate placed at 0.6 mm distance, which was a glass slide either pure or covered with biomaterials. While the low-absorptivity biomaterial absorbing layers proved to be ineffective in transfer of cells, when applied on the surface of acceptor plate, the wet gelatine and Matrigel layers successfully ameliorated the impact of the cells, which otherwise did not survive the arrival onto a hard surface. The best short- and long-term survival rate was between 65% and 70% for neuroblastoma and astroglial cells. The long-term survival of the transferred osteosarcoma cells was low, while the myeloid leukemia cells did not tolerate the procedure under the applied experimental conditions.

Directed Cell Growth on Laser-Transferred 2D Biomaterial Matrices

Patterned arrangement of living cells to form tissues on a given surface is the prerequisite of successful bioen- gineering, tissue building and biosensor technology. The aim of the present study was to deposit various biomaterials onto a given substrate to establish a patterned cellular matrix using laser-based technologies. We used the Pulsed Laser Deposi- tion and the Absorbing Film-Assisted Laser-Induced Forward Transfer methods to deposit various biomaterials, such as fibronectin, collagen and endothelial cell growth supplement. Subpicosecond KrF excimer laser was used for irradiation of the target materials. When cultured neuroectodermal stem cells, astrocytes, endothelial and neuroblastoma cells were layered on the deposited biomaterial patterns a guided growth of these cells was induced along the patterned thin film. Some cell types showed various interactions when approached each other. The above methods are suitable to build an ar- chitecture of substrates which supports and guides the growth of cells and may enable the cells to induce directed and rapid repair of injured tissues.

The Molecular Background of the Differential UV Absorbance of the Human Lens in the 240–400 nm Range

The ultraviolet (UV) absorption of various sections of the human lens was studied and compared with protein expression paralleling differential UV absorbance in anterior and posterior lenticular tissue. The UV absorbance of serial lens cryostat sections (60 μm) and that of lens capsules was determined using a Shimadzu scanning spectrophotometer, and the absorption coefficients were calculated. Two‐dimensional gel electrophoresis was performed using two pooled lenticular protein extracts (anterior and posterior sections). Protein spots were quantified and significantly different spots were identified by mass spectrometry following in‐gel digestion with trypsin and chymotrypsin. The UV‐C and UV‐B absorption of the human lens increased toward the posterior parts of the lens. The anterior and posterior lens capsules also effectively absorbed UV radiation. Levels of molecular chaperone proteins Beta‐crystallin B2 (UniProtKB ID:P43320), A3 (UniProtKB ID:P05813) and of glyceraldehyde 3‐phosphate dehydrogenase (UniProtKB ID:P04406) were significantly higher in the anterior part of the lens, whereas lens proteins Beta‐crystallin B1 (UniProtKB ID:P53674) and Alpha‐crystallin A chain (UniProtKB ID:P02489) were higher in the posterior sections. These results provide evidence that differential UV absorption in the anterior and posterior lens is accompanied by differential protein expression.

Erdheim-Chester's disease of the heart: a diagnostic conundrum and collision with the same mass in the orbit.

Erdheim-Chesters disease is a rare multisystem xanthogranulomatosis, afflicting the skeletal system with the occasional involvement of soft tissues. We delineate an unusual case of a cardiac variant of Erdheim-Chesters disease presenting with pericardial effusion and as a collision with a synchronous orbital manifestation. We describe our diagnostic pathway and propose a novel treatment option involving nonsteroidal anti-inflammatory drugs. The role of cyclo-oxygenase in the disease process and inhibition thereof by NSAIDs is hypothesized and discussed.

Amniotic membrane transplantation in cases of corneal calcification – follow up with ultrasound biomicroscopy

ZusammenfassungHINTERGRUND: Vorstellung der Amnionmembrantransplantation (AMT) als geeignetes therapeutisches Mittel zur Behandlung von tiefer Hornhautverkalkung. Darlegung der Zweckmäßigkeit der Ultraschall-Biomikroskopie (UBM) bei der Evaluierung und den Folgeuntersuchungen (Follow up) von Patienten mit tiefen Hornhautverkalkungen. MATERIAL UND METHODE: Zur Behandlung von kornealen Verkalkungen wurde an drei Patienten AMT vorgenommen. Als diagnostische Mittel kamen ophthalmologische Standarduntersuchungen und UBM zur Anwendung. Nach Entfernung der verkalkten Corneateile wurden auch histologische Untersuchungen durchgeführt. RESULTATE: Nach der Operation integrierte sich die Amnionmembran in die Hornhautstruktur. Die intraoperativ entfernten Corneateile wiesen Kalziumkristallablagerungen auf. SCHLUSSFOLGERUNG: Das Auftreten von Hornhautverkalkungen korrelierte mit der chronischen Verabreichung von phosphatgepufferten Augentropfen. Nach Entfernung der verkalkten Teile der Cornea führte die AMT zu einer zufriedenstellenden Epithelialisierung.SummaryBACKGROUND: To show and demonstrate amniotic membrane transplantation as a useful therapic tool to treat corneal calcification. To demonstrate the usefulness of ultrasound biomicroscopy in evaluation and following up patients with corneal calcification. MATERIAL AND METHODS: Three patients with corneal calcification were treated with amniotic membrane transplantation. The diagnostic tools included basic ophthalmological examinations and UBM. Histological examinations were also carried out after removal of the calcified corneal part. RESULTS: After surgery, the amniotic membrane integrated in the corneal structure. The intraoperatively removed cornea pieces proved to contain calcium salt crystals. CONCLUSIONS: The presence of corneal calcifications correlated with chronic administration of phosphate- buffered eye drops. After removing the calcified corneal area, amniotic membrane transplantation induced satisfactory epithelial growth.

Surface roughness investigations of excimer-laser-ablated cornea

The earlier investigations showed that the corneal haze can be due to the scattering effect of the excimer laser induced surface structure. In this paper a comparative study is presented regarding the development of these. Several human corneas were irradiated by an ArF excimer laser. The applied fluence was 193 mJ/cm2. The developed surface structures after each excimer pulse were investigated by an atomic force microscope under physiological salt solution in natural environment. It was found that the structures of cells and fibers forming the cornea were observable on the ablated surface in the form of surface roughness. Scanning electron microscopic observations were also performed to compare the two surface investigation methods. It was found that this showed the same structures, but differently from the atomic force microscopic observation some distortions appeared produced by preparation processes of the samples, which were necessaries for the electron microscopic investigations.