marketplaces often suffer from the low level of liquidity. Attracting members
is critical, however, not even a sound and efficient IT and logistic
background is enough to convince both the supplier and the customer side. In
this paper the authors present the case study of Sunbooks Ltd. This venture
has started to transform the Hungarian book trade market that suffers from
serious deficiencies in field of information and material flow. Despite the
vast investments and that the marketplace is prepared to serve the whole
Hungarian book industry, the market share started to grow very slowly. The
authors identify three contingency factors which can be accounted for the
evolution dynamics of this virtual network. They explain how the business model
is subjected to the evolution of market characteristics, and how the third
factor, the “soft issues” determine the evolution opportunities even in a
supporting market situation.
Authors:Ágnes Móricz, Györgyi Horváth, and Péter Ott
The antibacterial effect of the components of clary sage (Salvia sclarea L.) and spearmint (Mentha spicata L. var. crispa (Bentham) Danert) was investigated by means of high-performance thin-layer chromatography-direct bioautography against the Gram-positive soil bacterium Bacillus subtilis (Bs) and Gram-negative bacteria such as a pepper pathogen Xanthomonas euvesicatoria (Xe), a luminescence gene-tagged Arabidopsis pathogen Pseudomonas syringae pv. maculicola (Psm) and a luminescent marine Aliivibrio fischeri (Af). Sclareol, linalool, and linalyl acetate were identified as active components of clary sage and carvone as the antibacterial substance in spearmint. Sclareol inhibited all tested bacteria, linalool and carvone showed antibacterial effect against all Gram-negative strains tested, while linalyl acetate only against Xe and Af. Some minor components of the clary sage essential oil also gave a zone of inhibition when tested on Gram-negative bacterium strains.
Direct bioautography performed with luminescence gene-tagged bacteria enables almost real-time detection of antimicrobial compounds in plant extracts. This method for the detection of chamomile (
) components with antibacterial effect against Bacillus subtilis soil bacteria was more sensitive than commonly used bioautographic visualization by staining with a tetrazolium salt. Some compounds had a strong inhibiting effect only via the bioluminescence measurement. Extraction of antibacterial components of chamomile flowers was most effective with 50% ethanol; slightly lower efficiency was achieved with acetone and methanol, and hexane was least effective. The results were confirmed by using luminescent
Pseudomonas syringae pv. maculicola
plant pathogen bacteria.
Singlet oxygen (
)-catalyzed oxidation of water leads to a variety of oxidants (e.g. ozone, O
) in host-parasite relationships as well. It can be detected indirectly in TLC or OPLC zones by use of the simple BioArena system and O
-eliminating molecules (e.g.
-limonene and indigo carmine) in the culture medium. It follows from these new findings that not only formaldehyde but also O
and related bioreactive compounds may play a crucial role in the mechanism of antibacterial activity of antibiotic-like compounds. The toxic potential of a molecule, however, originates from the ratio of the oxidants produced in the chromatographic spots.
Authors:Imre Gerlinger, Péter Bakó, Krisztina Somogyvári, Péter Móricz, and József Pytel
Development of surgical treatment of otosclerotic stapes fixation is one of the success stories of otology during the past five decades. Nowadays not only stapedectomy and partial stapedectomy but stapedotomy can also be considered a well-established otological procedure.
To introduce this minimally invasive surgical technique into the Hungarian otolaryngology practice, to gain useful experiences, and to analyze the hearing improvements and postoperative complications.
The authors give account of their first clinical experiences with 14 patients with KTP laser assisted stapedotomies using the self-crimping Nitinol piston. A total of 14 patients (11 females, 3 males) who have undergone the procedure between March 2006 and April 2007 were reviewed. The average age of the patients was 42.2 years, 6 procedures were carried out on left ears and 8 on right ones. The average length of follow-up was 9 months (ranging from 6 weeks to 1 year).
Pure tone audiograms documented a hearing threshold improvement of 21.5 dB averaged across 0.5–1–2–3 kHz frequencies. The air-bone gap improvement averaged on the same frequencies was 18.7 dB. After an average 9 months postoperative follow-up period, the average air-bone gap was < 10 dB in 85% of the patients, however < 20 dB in 100% of the patients. As for the average air conduction result: it was < 30 dB in each patient except one. In this series, neither facial nerve paresis nor high frequency deterioration of the bone conduction thresholds was reported in the postoperative follow-up period.
Based on the authors’ favourable experiences and the review of the literature, KTP laser assisted stapedotomy with the use of Nitinol piston has several advantages: 1. the laser-activated memory effect of the piston prevents the disadvantages of the crimping manouvre made around the long process of the incus; 2. vertigo, experienced in the early postoperative period is milder and takes shorter time, reducing the length of hospitalisation; 3. the procedure is cost-effective and minimally-invasive; 4. application of KTP laser assures a bloodless operating field and minimal cochlear trauma; 5. migration of the prosthesis can be prevented, the degree of the surrounding granulation is less; 6. high frequency hearing improvement can be achieved on the long run; 7. the frequency and seriousness of complications are less, therefore this technique can be reccommended for unexperienced ear surgeons too; 8. the procedure can be used in difficult situations, too, e.g. in the presence of stapedial artery, obliterative otosclerosis, floating footplate, abnormal position of the facial nerve in the middle ear, revision cases; 9. the interindividual differences of hearing results are much less. Based on their favourable initial experiences, the authors plan to conduct a long-term follow-up on a greater number of patients.
Authors:Ágnes M. Móricz, Dániel Krüzselyi, and Péter G. Ott
In this study, the antibacterial profiling of the ethanolic leaf extract of greater burdock (Arctium lappa L.) is demonstrated, applying thin-layer chromatography (TLC) coupled bioassays against the Gram-positive soil bacterium Bacillus subtilis and the Gram-negative pepper pathogen Pseudomonas syringae pv. maculicola. The main active component was isolated by eluting from the adsorbent bed and subjected to a targeted characterization by high-performance liquid chromatography–diode array detection–electrospray ionisation–mass spectrometry. The identification of the germacranolide sesquiterpene lactone onopordopicrin was based on its retardation factor, bioactivity in TLC-based methods, and retention tim as well as ultraviolet (UV) and mass spectra, compared to those of the reference substance isolated earlier in our laboratory from Onopordum acanthium leaf.
Authors:Ágnes M. Móricz, Dániel Krüzselyi, and Péter G. Ott
Overpressured layer chromatography (OPLC), ensuring pumpforced constant mobile phase flow and the possibility of overrun, offers the expanded exploitation of fine-particle adsorbent layers for a longer development distance. Using an infusion—transfusion OPLC method with a 26-cm long development, the separation of clove, rosemary, eucalyptus, tea tree, spearmint, thyme, and cinnamon bark essential oil components was achieved with good resolutions. In the combination of OPLC and Aliivibrio fischeri assay, the main essential oil components eugenol, borneol, (−)-R-carvone, thymol, and trans-cinnamaldehyde exhibited antibacterial effect. The OPLC—2,2-diphenyl-1-picrylhydrazyl (DPPH*) test showed two antioxidant components: eugenol and thymol.
Authors:Ágnes Sárközi, Ágnes Móricz, Péter. Ott, Ernő Tyihák, and Ágnes Kéry
The greater celandine (
L.), a well-known source of isoquinoline alkaloids, has a long history of use as a medicinal plant. Although the antimicrobial activity of
alkaloids against pathogenic bacteria has been reported, the mechanism of this action is almost unknown. The BioArena system, which integrates the modern method and biological results of bioautography with TLC and/or OPLC, is especially suitable for investigating biochemical interactions in the adsorbent layer after chromatographic separation. The antimicrobial effect of alkaloids obtained from
root has been demonstrated by use of this system. It was assumed that the antibiotic activity of
alkaloids was a result of formation of formaldehyde. It was also assumed that addition of endogenous HCHO-capture molecules, for example l
-arginine and glutathione, to the culture medium reduces the antibacterial activity of
alkaloids whereas Cu(II) ions enhance the effect. The results obtained support these assumptions and our earlier observations that HCHO and its reaction products are very important in the antibiotic action of these compounds. These small molecules (l
-arginine and glutathione) can capture HCHO molecules mobilized by alkaloids and possibly by pathogen cells, and may be responsible for reduced antibacterial effect. The HCHO-mobilizing power of Cu(II) ions dramatically enhanced the antibiotic effect. The BioArena system is highly suitable for studying special interactions in the adsorbent layer.
Authors:Ernő Tyihák, Ágnes Móricz, Péter Ott, Michal Hajnos, and Kazimierz Głowniak
The accumulation of hydrogen peroxide (H
) is an early and crucial step in paclitaxel-induced cancer cell death before commitment of the cells to apoptosis. In these intracellular events formaldehyde (HCHO) as endogenous, indispensable component may be present mainly as hydroxymethyl groups and so there is a possibility of its endogenous interaction with H
in which singlet oxygen (
) and excited HCHO (H*CHO) can be formed.
can interact with H
O molecules and in this interaction dihydrogen trioxide (H
) is formed. The disproportion of this molecule — among others — results in ozone (O
). It is supposed that this reaction series is also valid for the conditions in layer chromatographic spots after inoculation. Results with paclitaxel support this idea. Using BioArena as a complex bioautographic system the HCHO molecules could be captured with well-known endogenous HCHO capture molecules (l
-arginine, glutathione) in the spots of paclitaxel on the TLC/OPLC adsorbent layer after inoculation. Capture of HCHO resulted in a dose-dependent decrease of the antibacterial activity of paclitaxel. The antibacterial activity of paclitaxel in the chromatographic spots can be increased dramatically by using Cu(II) ions as HCHO-mobilizing and carrier ions in the culture medium. The HCHO molecule can
-hydroxymethylate the C3’ amide of paclitaxel. By applying an O
scavenger (e.g. indigo carmine) this oxidant, as a key reaction product of HCHO, could be detected indirectly in chromatographic spots of paclitaxel. It seems that these small molecules — from HCHO to endogenous O
— may be crucial factors of the mechanism of antiproliferative action of the paclitaxel including killing of bystander cancer cells also. It seems that the basic molecule (paclitaxel) does not have a direct effect on the bacterial cells; its induction of the formation of H
molecules (and indirectly HCHO molecules) may, however, be resulting in this complicated process.
Authors:Ernő Tyihák, Ágnes Móricz, Judit Mátyási, Péter Ott, and József Balla
The present and more recent observations suggest that the ozone is an indispensable, endogenous molecule form, and so it can be detected and measured practically in all biological systems. There are already different indirect and direct methods for the detection and measurement of this small molecule. The endogenous formation of ozone in the biological world may open a totally new horizon, e.g., in the topics of disease resistance and cell proliferation. Special efforts and more and more efficient methods are needed for observing the endogenous reactions and functions of this very reactive key molecule.