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V Král

Publications and source records attributed to V Král.

At least 19 recordsLinked to original sources
PubMed2001

Open-tubular electrochromatography of organic phosphates on a sapphyrin-modified capillary.

Sapphyrin coating of the inner wall of the capillary results in a distinct interaction of the phosphate residue-possessing compounds as proven by a seven-membered model mixture of nucleoside mono- and diphosphates and ATP. Modification of the inner surface of the capillary not only alters the endoosmotic flow (as would have been expected) but brings about an electrochromatographic effect based on the interaction of tested phosphate moiety-bearing solutes with the immobilized sapphyrin layer. Elution of the sample can be achieved by using either 25 mM borate-acetate buffer in which monophosphates are not only separated from each other, but also selectively separated from di- and triphosphates (ATP). With the other two buffer systems tested, i.e. borate-phosphate and Tris-HCl, better selectivity (though smaller interaction with the capillary coating) was observed. The coating is relatively stable (can be used for 20 subsequent runs at least), simple to materialize, and in spite of a strong UV absorbancy of sapphyrin at the wavelength used (254 nm), decreases the limit of detection by no more than one order of magnitude as compared to the untreated capillary. Resolution factors (calculated to the preceding peak) are in most cases better in the electrochromatographic separation mode as compared to the separation in the untreated capillary, which reflects both the decrease in the electroosmotic flow and the interaction with the capillary wall coating.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2001

Novel porphyrin-cryptand cyclic systems: receptors for saccharide recognition in water.

Two macrocyclic porphyrin sandwich systems, 4 and 5, together with the linear compound 6 have been prepared and examined as saccharide receptors. The cyclic porphyrin-cryptand conjugates 4 and 5 bind saccharides efficiently in highly competitive media with a preference for trisaccharides probably due to a complementary topology of hydrophobic and hydrophilic solvating regimes with respect to the sugar guests.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed2001

Noncovalent interactions of peptides with porphyrins in aqueous solution: conformational study using vibrational CD spectroscopy.

Noncovalent interactions of poly(L-lysine) (PL), oligopeptides L-lysyl-L-alanyl-L-alanine and (L-lysyl-L-alanyl-L-alanine)(2) with meso-tetrakis(4-sulfonatophenyl)porphine (TPPS), and poly(L-glutamic acid) (PLGA) with meso-tetrakis(1-methyl-4-pyridyl)porphine tetra-p-tosylate (TMPyP) in aqueous solutions have been studied using combination of spectroscopic methods: Vibrational circular dichroism (VCD) spectroscopy in the mid-infrared region provides a direct information on conformational changes of the polypeptides and oligopeptides caused by interactions with porphyrins; ultraviolet-visible absorption, fluorescence, and electronic circular dichroism (ECD) reveal the aggregation characterization of the porphyrin part of the complexes. Interactions of TPPS with tripeptide, hexapeptide, and PL containing about ten amino acid residues in the molecular chain are accompanied with the changes of VCD patterns in the amide I' region. In these cases, the conformation of the oligopeptide part of complexes is obviously influenced by interactions with TPPS and partial changes of random coil structure are observed in VCD. When PL was composed of the hundreds of lysine residues, just a weak intensity decrease was detected and the shape of VCD spectrum typical for the random coil structure was preserved. As follows from the uv-vis absorption and fluorescence spectra, porphyrin molecules are attached to peptides by electrostatic interaction as a monomer or dimer and interaction between porphyrin and peptide depends on the polypeptide chain length. For the PLGA-TMPyP system with PLGA containing from tens to hundreds of glutamic acid residues in the chain, the VCD spectra were unchanged when TMPyP was presented in the aqueous solution of PLGA and random coil conformation of PLGA-TMPyP aggregates was preserved.

Biocompatible Materials↗
PubMed2001

[Effect of portosystemic anastomosis on the degree of splenic inhibition].

UNLABELLED: Secondary hypersplenism is a well-known complication of portal hypertension. Reduced platelet count is a more alarming sign for the physician than risk for the patient. Improvement of thrombocytopenia is urgent, when portal hypertension with splenomegaly and thrombocytopenia presents with life-threatening haemorrhage from gastroesophageal varices. In this case, treatment aimed at stopping the bleeding may be more beneficial than any intervention on the spleen. In this study, we evaluated long-term effects of an elective distal splenorenal shunt or small diameter H-shunt on splenomegaly and thrombocytopenia in 26 patients with portal hypertension operated for repeated bleeding from oesophageal varices. 25 patients had splenomegaly and 16 patients had thrombocytopenia before shunting. Surgery corrected splenomegaly in 16 patients (64%), platelet counts increased in 13 of 16 patients with thrombocytopenia (81.2%). CONCLUSION: Selective or partial portal decompression is sufficient to alleviate thrombocytopenia and splenomegaly associated with portal hypertension.

Adult↗
PubMed2001

[Hyperparathyroidism in clinical practice. Personal experience].

The period of six years is discussed by the authors during which 39 patients were confirmed having primary or secondary hyperparathyroidism. All of them finally underwent the surgical procedure. The possibility of immunoreactive PTH measurement has been highly appreciated. Despite that key position of the experienced surgeon remains of the utmost importance.

Adult↗
PubMed2001

[Laparoscopic repair of bilateral inguinal hernias: results at the First Surgical Clinic in Olomouc].

OBJECTIVE: The aim of this paper is to evaluate the outcome of the TAPP (transabdominal preperitoneal) repair of bilateral inguinal hernia with one large mesh. METHODS: Eighteen patients with the bilateral inguinal hernia had TAPP repair with one mesh. The operation and the postoperative course has been discussed. RESULTS: None operative complications were noted, postoperatively four groin haematomas and one recurrence were observed. CONCLUSION: TAPP is safe and effective for the repair of the bilateral inguinal hernias.

Female↗
PubMed2001

[Are problems with portosystemic shunts still a reality and is shunt selectivity the deciding factor for justifying its use?].

OBJECTIVE: The objective of the work is detailed evaluation of portosystemic shunts. The criterium of suitability and justification is their selectivity and preservation in the course of time. METHODS: The authors used a clinical group of patients who had either a Warren shunt or a mesocaval H-shunt with a limited blood flow (diameter 8 mm). In these patients the blood flow was assessed by dopplerometry in the portal vein and before the shunt, i.e. in the lienal or possibly mesenterial vein. RESULTS: Of 32 shunts made during the last five years it was possible to make 12 assessments (8 Warren and 4 H-mesocaval shunts). An adequate decline in the blood flow in the portal vein was recorded and a corresponding increase in the lienal or mesenteric vein. Even after one year no marked drop in the flow through the portal vein was recorded. CONCLUSION: A distal Warren shunt and H-mesocaval shunt with a restricted blood flow preserve the signs of selectivity even after one year. An adequate blood flow through the liver is also preserved. From this aspect selective shunts are still suitable treatment of portal hypertension. Obviously correct indication is the basic prerequisite of success.

Blood Flow Velocity↗
PubMed2000

Mapping the active site polarity in structures of endothelial nitric oxide synthase heme domain complexed with isothioureas.

Analyzing the active site topology and plasticity of nitric oxide synthase (NOS) and understanding enzyme-drug interactions are crucial for the development of potent, isoform-selective NOS inhibitors. A small hydrophobic pocket in the active site is identified in the bovine eNOS heme domain structures complexed with potent isothiourea inhibitors: seleno analogue of S-ethyl-isothiourea, S-isopropyl-isothiourea, and 2-aminothiazoline, respectively. These structures reveal the importance of nonpolar van der Waals contacts in addition to the well-known hydrogen bonding interactions between inhibitor and enzyme. The scaffold of a potent NOS inhibitor should be capable of donating hydrogen bonds to as well as making nonpolar contacts with amino acids in the NOS active site.

Binding Sites↗
PubMed2000

Vibrational circular dichroism of tetraphenylporphyrin in peptide complexes? A computational study.

The Raman and absorption spectra of tetraphenylporphyrin (TPP) were calculated and compared to experiment. The computation was based on the harmonic molecular force field and electric tensors obtained ab initio at the BPW91/6-31G* level. Good agreement was found between experimental and calculated frequencies and intensities. In order to estimate whether induced optical activity in chiral complexes interferes with the signal of peptide vibrations, the vibrational circular dichroism (VCD) spectra of TPP were simulated. The magnetic field perturbation theory (MFP) and the gauge-invariant atomic orbitals (GIAO) were used for the simulation. Such spectra were compared to theoretical VCD intensities of a model tripeptide as well to experimental spectra of a complex of the peptide and tetrakis(p-sulfonatophenyl)porphyrin (TSPP). No significant contribution to VCD signal from the TPP residue was found in experimental spectra. Thus, possible peptide conformational changes occurring during the complexation can be monitored directly in the amide I frequency region.

Circular Dichroism↗
PubMed2000

Long-range assemblies on poly(dG-dC)2 and poly(dA-dT)2: phosphonium cationic porphyrins and the importance of the charge.

The present paper describes synthesis and spectroscopic properties of novel cationic meso-tetraphenylporphyrins bearing two (trans) (P2) or three (P3) triphenylphosphonium substituents. The porphyrin aggregation in aqueous solutions is discussed in detail. Porphyrin binding to and self-organization onto long-range assemblies on poly(dA-dT)2 or poly(dG-dC)2 were probed by combination of absorption, fluorescence, circular dichroism (CD), transient and resonance light-scattering (RLS) techniques. The higher hydrophobicity of P2 is manifested by more extensive self-organization. Induced CD and intensive RLS indicate binding to the chiral environment on the nucleic acids exterior and exciton coupling between adjacent porphyrin moieties. The CD spectra of P2 on poly(dG-dC), and poly(dA-dT)2 suggest that the binding geometry is essentially independent of the base sequence. The fluorescence lifetime of about 4 ns was attributed to the long-range assembly. In the case of P3 the distinctly different CD spectra induced by GC or AT base-pair regions reveal that the number of the substituents determines how closely the porphyrin can approach the specific electronic environment on the nucleic acid exterior. The fluorescence lifetime of the P3 assembly is about 2 ns.

Circular Dichroism↗
PubMed2000

Calixphyrins: Novel Macrocycles at the Intersection between Porphyrins and Calixpyrroles This work was supported by the National Institutes of Health (CA-68682, GM-58907, and TW-00682 to J.L.S.), the National Science Foundation (CHE-9725399 to J.L.S. and CHE-9807702 to V.L. for the purchase of the Nonius Kappa CCD), the Howard Hughes Foundation (V.K. and J.L.S.), the Grant Agency of the Czech Republic (No. 203/97/1099 to V.K.), the Ministry of Education (No. VS-97135 and Project CEZ: J19/98: 223400008 to V.K.), and the Howard Hughes Medical Institute (74195-541101 to V.K.).

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Journal Article↗
PubMed2000

[Treatment of esophageal achalasia].

During the past years the authors performed at the First Surgical Clinic, Faculty Hospital Olomouc laparoscopic cardiomyotomy with Dor's plastic operation in 17 patients with achalasia of the oesophagus. From the above number 15 patients were relieved of their complaints, two patients were reoperated. The cause of failure of the operation was in one case previous treatment with botulotoxin, in the other case achalasia grade IV, refractory to this type of treatment. The authors consider laparoscopic oesophago-cardiomyotomy a safe procedure, effective in particular in the earlier stages of the disease. They warn against excessive protraction of surgical treatment, frequently caused by selection of ineffective non-surgical therapy.

Adult↗
PubMed2000

[Significance and possibilities of cytostatic treatment of malignant tumors: testing the effects of cytostatics].

The authors present an account on the initiation of a study concerned with the administration of cytostatics according to the sensitivity of the tumour cells. To assess the sensitivity the MTT test was used. The method is described in the paper. Four groups of tumours were examined by the MTT test: breast cancer, carcinoma of the colon and rectum, of the lungs and oesophagus + stomach. Six cytostatics were tested: 5-fluorouracil, cisplatinum, daunorubucin, paclitaxel, vincristine, and vepeside. Evaluation of the sensitivity of different tumours was based on the median of TCS50. The results of the MTT test were not used so far in the therapeutic protocol in all patients where the examination was made, as in solid tumours, contrary to haemo-blastomas, usually common empirically tested protocols are used. The authors reflect whether individually administered cytostatics according to the MTT test can improve the prognosis of patients with malignant diseases. They assume that long-term follow-up of the patients may provide favourable results in particular because more and more effective cytostatics are becoming available.

Antineoplastic Agents↗
PubMed2000

[Gene therapy of liver tumors].

The aim of this review is to describe current possibilities of gene therapy in liver tumours. The authors discuss the following methods which were used in experimental clinical trials: tumour suppressor genes, suicide gene therapy, immunogene therapy and use of oncolytic viruses. The results from these first clinical trials were encouraging. However, because of the present limitations, such as safe transport and selective expression of genes in the malignant cells, gene therapy cannot be used as a definitive treatment for liver tumours.

Genetic Therapy↗
PubMed2000

Oncological problems associated with Barrett's oesophagus.

Reflux oesophagitis does not represent only an isolated collection of symptoms affecting the patients' quality of life but the risk of serious complications including the benign stenosis and carcinoma of oesophagus, too. Barrett's oesophagus (BO) has the highest risk for development of the neoplasia due to reflux oesophagitis.

Barrett Esophagus↗