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J Kos

Publications and source records attributed to J Kos.

At least 55 records · Page 3Linked to original sources
PubMed1997

Enzyme-linked immunosorbent assay for the detection of total cathepsin H in human tissue cytosols and sera.

An enzyme-linked immunosorbent assay (ELISA) was constructed for the determination of total human cathepsin H concentration in clinical samples. Utilising monoclonal and polyclonal antibodies, raised to human liver cathepsin H, the assay is able to detect a mature protein, a precursor molecule and enzyme-inhibitor complexes. The test system permits sensitive and reliable detection of analyte either in tissue cytosols or in sera. The detection limit is 2 ng/ml (n = 10, mean of zero standard +/- 3 SD). The average recovery of cathepsin H, added to the low content samples, was 95.3% +/- 1.8%. The within-run and between-run coefficient of variance (CV) varied from 2.3% to 8.9% and 12.7% to 16.4%, respectively, indicating satisfactory reproducibility of the method. The level of cathepsin H was defined in tissue cytosols of human heart, muscle and kidney and in sera from 30 healthy individuals. Additionally, cathepsin H was measured in sera from 55 patients with primary skin melanoma and from 42 patients with metastatic melanoma. The mean cathepsin H level was significantly higher for both groups of patients compared to normal sera level, being highest for metastatic melanoma patients.

Animals↗
PubMed1997

Expression of cysteine protease inhibitors stefin A, stefin B, and cystatin C in human lung tumor tissue.

In human lung tumor tissue specimen (n = 73) concentrations of stefins A and B were found to be increased 2.0-fold (p < 0.01) and 1.3-fold (p < 0.01), respectively, as compared to matched normal tissue. Stefin A and B concentrations were higher in primary tumors than in secondary tumors, i.e. metastases from other organs to the lung (p < 0.01; p < 0.05, respectively). Cystatin C concentrations were rather low and did not differ between tumor and normal tissue. Both concentrations of stefins did not correlate with TNM stages. Stefin A was higher in squamous cell carcinoma than in adenocarcinoma (p < 0.01), while stefin B did not show such a difference. At investigation of a relationship between survival probability of patients with primary tumors it was found that increased stefin B concentrations and total cysteine-protease-inhibitory activities but not stefin A concentrations were positively correlated with survival probability. It is concluded that stefins A and B are major contributors to the cysteine protease inhibitory activity in primary lung tumors. Stefin B proved to be a prognostic factor, especially in squamous cell carcinoma.

Adolescent↗
PubMed1997

Prognostic value of cathepsins B, D and steffins A and B in laryngeal carcinoma.

Concentrations of cathepsins A, D and stefins A and B were measured in primary tumor and adjacent normal tissue of 25 patients with laryngeal carcinoma. Median concentrations of both cathepsins and that of stefin B were significantly higher in tumor tissue than in their normal counterparts (cathepsins B and D, P < 0.0001; stefin B, P = 0.01), indicating their possible involvement in the process of tumor spread. Early (T1 and T2) tumors had lower concentrations of stefins A and B than locally advanced (T3 and T4) tumors (P = 0.04). Disease-free and disease-specific survival rates at 45 months were significantly better in patients with tumor concentrations of stefins above or equal to the cut-off values (stefin A, P = 0.001 and P = 0.004; stefin B, P = 0.048 and P = 0.008), indicating that these might be of prognostic value. The concentrations of cathepsins B and D did not correlate with survival.

Adult↗
PubMed1997

Effects of a 2-day abstinence from smoking on dietary, cognitive, subjective, and physiologic parameters among younger and older female smokers.

In a field study, dietary intakes, subjective ratings of well-being, cognitive performance, blood pressure, and heart rate were assessed during 6 days of ad libitum smoking and 2 days without smoking by using an electronic diary. The subjects were 59 younger and older female smokers, aged 25-35 and 55-65 years, respectively. Smoking abstinence significantly lowered heart rate, blood pressure, and saliva cotinine levels, indicating a good compliance by the subjects. Smoking abstinence was also followed by subjectively reported decreased levels of relaxation and activity and by higher levels of sleepiness, negative strain, and craving for smoking. Mental performance as assessed with the Stroop task was not affected by smoking abstinence. Whereas the percentage distribution of the macronutrients did not change with smoking abstinence, the intake of total energy increased significantly by 182 kcal/day. Main effects of age were found on some of the dietary parameters and Stroop performance variables only. A post hoc analysis revealed a significant influence of the employment status factor on the excess caloric intake and the increased frequency of sweet consumption when under abstinence. These increases were significantly greater in nonemployed (housewives, jobless) than in working women. Further correlational analysis revealed strong relations between caloric intake and simultaneous craving for smoking and food during abstinence but not during nonabstinence days, whereas no relation between caloric intakes and saliva cotinine or respiratory carbon monoxide were obtained. These findings suggest that the availability of food products and subjective withdrawal symptoms are probably more important moderators of increased dietary intake following smoking cessation than any pharmacologic systemic effects of nicotine.

Adult↗
PubMed1997

Brain-mediated protective interactions of histaminergic H2 and dopaminergic systems in rats.

Pretreatment with dopamine agonists (bromocriptine 2.5, L-dopa 2.5, apomorphine 0.05 mg/kg i.p.) and a histamine H2 receptor antagonist (cimetidine 50.0 mg/kg i.p.) was found to greatly reduce the haemorrhagic gastric lesions induced by 15-min pylorus ligation in rats. On the other hand, pretreatment with dopamine antagonists (haloperidol 5.0, sulpiride 1.0, domperidone 5.0 mg/kg i.p.) significantly aggravated these lesions. Cimetidine markedly diminished the ulcerogenic effect of haloperidol but not that of domperidone, suggesting a brain-mediated site for the protective interaction of cimetidine and dopamine systems.

Animals↗
PubMed1997

Thermal denaturation of human cystatin C and two of its variants; comparison to chicken cystatin.

Thermal denaturation of the recombinant human cystatin C, an 8-residue shorter variant (Leu-9 cystatin C), and the W106S mutant were measured using differential scanning calorimetry (DSC). The finding that Leu-9 cystatin C is of similar stability to the full length protein is in accordance with its nearly normal inhibitory activity. The variant W106S cystatin C exhibits a higher melting temperature by 4 degrees than the wild-type protein. This contrasts with its reduced inhibitory activity and represents an example where activity changes are due to local effects and are not correlated to stability. From the ratio between Van't Hoff and calorimetric enthalpies it is judged that recombinant human cystatin C and Leu-9 cystatin C are dimeric prior to thermal unfolding whereas W106S cystatin C is monomeric. Melting temperatures and estimated stabilities for some other members of the cystatin superfamily of the cysteine proteinase inhibitors are presented which have been recorded previously or were collected for this study (chicken cystatin). It is concluded that thermal stability of human cystatin C (Tm = 82 degrees C) is placed in between the more stable human stefin A (Tm = 95 degrees C) and the less stable human stefin B (Tm = 66 degrees C) whereas chicken cystatin behaves as a thermophilic protein, melting above 115 degrees C. To illustrate secondary structure changes, thermal denaturations of the recombinant human cystatin C and of W106S cystatin C were followed by circular dichroism in the far UV. It was found that the change in tertiary structure (revealed by DSC) precedes the major change in secondary structure.

Animals↗
PubMed1997

Cathepsins B, H, and L and their inhibitors stefin A and cystatin C in sera of melanoma patients.

The levels of cathepsins (Cats) B, H, and L and their inhibitors stefin A and cystatin C were determined in the sera of 43 patients with metastatic melanoma, in 54 patients with treated cutaneous melanoma with no evidence of metastatic disease, and in 30 healthy blood donors, using quantitative ELISAs. The levels of Cats B and H and cystatin C were significantly higher within the group of metastatic melanoma patients compared with the healthy controls. The median Cat B was 4.8 versus 3.6 ng/ml (P < 0.013), the median Cat H was 13.7 versus 4.9 ng/ml (P < 0.0001), and the median cystatin C was 470 versus 320 ng/ml (P < 0.02). Cat H was also significantly increased within the group of melanoma patients with no metastasis, with a median of 9.6 ng/ml. Cat B was found to correlate with Cat L (r = 0.36; P < 0.02) and cystatin C (r = 0.41; P < 0.008). The serum level of Cat H was significantly increased in patients showing no response to the chemoimmunotherapy as compared to the level in responders. Metastatic melanoma patients with high contents of Cat B and Cat H experienced significantly shorter overall survival rates than the patients with low levels of each enzyme (Cat B: P < 0.003 and relative risk, 2.5; Cat H: P < 0.006 and relative risk, 2.4, using medians as cutoff values). The other potential factors for prognosis for this group of patients revealed moderate (histological type and age) or no (tumor thickness, sex, and lymph node metastasis) prognostic significance. Similarly, no difference in survival was found for stefin A, cystatin C, and Cat L. These results suggest that the serum levels of Cats B and H could serve as prognostic factors for patients with advanced melanoma.

Adult↗
PubMed1996

Interaction of human cathepsin C with chicken cystatin.

Cathepsin C was purified from human spleen by a rapid procedure, which included homogenization, ammonium sulfate precipitation, gel filtration on Sephacryl S-200 and finally affinity chromatography on chicken cystatin-Sepharose. The interaction between cathepsin C and chicken cystatin was further characterized. It was found to be accompanied by a maximum decrease in fluorescence emission intensity at 336 nm. Fluorescence titration showed that human cathepsin C can bind four chicken cystatin molecules. The 4:1 binding stoichiometry was confirmed by titration monitored by the loss of enzyme activity. A non-competitive-competitive type of inhibition was determined from a double-reciprocal Lineweaver-Burk plot with a Ki value of 0.22 nM for the non-competitive inhibition.

Animals↗
PubMed1996

Prognostic value of cathepsins B, H, L, D and their endogenous inhibitors stefins A and B in head and neck carcinoma.

To estimate the prognostic value of cathepsins B, H, L, D and stefins A and B in head and neck carcinoma, their concentrations in cytosols of primary tumours and adjacent normal tissue were measured (cathepsins B, D stefins A, B in 45, cathepsin L in 24 and cathepsin H in 21 patients). Median concentrations of cathepsins B, L, and D were significantly higher in tumour than in the adjacent normal tissue (B and D: p < 0.0001; L: p = 0.004); cathepsin H concentration was higher in normal tissue (p = 0.001). Concentrations of either stefin did not differ significantly between normal and tumour tissue. Concentrations of cathepsins B, H, L, and D were higher in laryngeal than in non-laryngeal normal and tumour tissues. The difference was statistically significant for cathepsin B in tumour tissue (p = 0.045), and marginally significant in normal tissue (p = 0.07). Early tumours had lower concentrations of stefins A and B than locally advanced tumours (stefin A: p = 0.04; stefin B: p = 0.07). Disease-free and disease-specific survival rates were better in patients with concentrations of cathepsin L in tumour tissue below or equal to the cut-off values (p = 0.035; p = 0.05), whereas for cathepsin B the difference was established only for disease-free survival (p = 0.07). The opposite was true for stefin A (p = 0.0002; p = 0.002) and stefin B (p = 0.009; p = 0.003), and in disease-free survival also for cathepsin H (p = 0.055). The concentration of cathepsin D did not correlate with survival. Our data indicate that cathepsins B, H, L and stefins A and B might have prognostic value in head and neck carcinoma.

Adult↗
PubMed1995

Regulation of the activity of lysosomal cysteine proteinases by pH-induced inactivation and/or endogenous protein inhibitors, cystatins.

The kinetics of pH-induced inactivation of human cathepsins B and L was studied by conventional and stopped-flow methods. The inactivation of both enzymes was found to be an irreversible, first-order process. The inactivation rate constants increased exponentially with pH for both enzymes. From log kinac vs pH plots, 3.0 and 1.7 protons were calculated to be desorbed for pH-induced inactivation of cathepsins L and B. Cathepsin B was thus substantially more stable than cathepsin L (approximately 15-fold at pH 7.0 and 37 degrees C). Cathepsin B was efficiently inhibited by cystatin C at pH 7.4, whereas the inhibition by stefin B and high molecular weight kininogen was only moderate. In contrast, cathepsin L was efficiently inhibited by both chicken cystatin and stefin B at this pH kass approximately 3.3 x 10(7) m-1 s-1).

Animals↗
PubMed1995

Lysosomal proteases cathepsins D, B, H, L and their inhibitors stefins A and B in head and neck cancer.

In cytosols of tumour and normal tissue of 53 patients suffering from head and neck carcinoma cathepsins D, B, H and L were measured using quantitative immunoreactive assays (ELISA). The values of cathepsins D, B and L were significantly higher in tumour tissue, whereas cathepsin H concentration was lower in tumour than in normal tissue. Median cathepsin D values were 27 pmol (tumour tissue) vs. 12 pmol (normal tissue) per mg of total protein, median cathepsin B values were 1.25 micrograms/mg (tumour tissue) vs. 0.23 micrograms/mg (normal tissue) and median cathepsin L values were 39.8 ng/mg (tumour tissue) vs. 20.0 ng/mg (normal tissue). Median cathepsin H values were 1.05 micrograms/mg and 2.20 micrograms/mg for tumour and normal tissue, respectively. Additionally, stefin A and stefin B were measured in tumour and normal tissue samples. In contrast to the cathepsins, the concentrations of these inhibitors of cysteine proteinases was not significantly different between tumour and normal samples. The concentrations of cathepsins D, B, H and L and stefins A and B measured in head and neck tumours, were independent of standard clinical and histological prognostic factors. Significant correlation of tumour tissue values was observed between cathepsins B and L and between both stefins.

Adenocarcinoma↗
PubMed1994

Comparison of in vivo and in vitro antimalarial activity of artemisinin, dihydroartemisinin and sodium artesunate in the Plasmodium berghei-rodent model.

The in vitro and in vivo antimalarial activity of artemisinin, artesunate and dihydroartemisinin has been compared using the Plasmodium berghei-rodent model. Drugs were added to synchronized short-term in vitro cultures of the erythrocytic stages and inhibition of parasite development was determined by measuring DNA synthesis by flow cytometry. Dihydroartemisinin was the most effective drug. IC50 values of artemisinin, artesunate and dihydroartemisinin were 1.9, 1.1 and 0.3 x 10(-8) M, respectively, when drugs were present during the complete 24 h developmental cycle. IC50 values increased significantly when drugs were added to old trophozoites, indicating that the older stages are less sensitive. To determine the in vivo antimalarial activity, mice with a parasitaemia between 1% and 3% were injected intramuscularly on 3 consecutive days with a single dose of the drugs dissolved in Miglyol 812. Again dihydroartemisinin was the most effective drug in vivo, showing a cure rate of 47% at 10 mg/kg bodyweight, while with both other drugs the recrudescence rate was 100% at the same dosage. This study showed that the P. berghei-rodent model is a useful tool for accurate comparisons of the in vivo and in vitro antimalarial activity of drugs.

Animals↗
PubMed1993

The structures of native phosphorylated chicken cystatin and of a recombinant unphosphorylated variant in solution.

The solution structures of the phosphorylated form of native chicken cystatin and the recombinant variant AEF-S1M-M29I-M89L were determined by 2D, 3D and 4D-NMR. The structures turn out to be very similar, despite the substitutions and the phosphorylation of the wild-type. Their dominant feature is a five-stranded beta-sheet, which is wrapped around a five-turn alpha-helix, as shown by X-ray crystallographic studies of wild-type chicken cystatin. However, the NMR analysis shows that the second helix observed in the crystal is not present in solution. The phosphorylation occurs at S80, which is located in a flexible region. For this reason, very few effects on the structure are observed. Comparison of structures of the unphosphorylated variant and the wild-type shows small effects on H84 which is located in the supposed recognition site of the serine kinase. This recognition site appears to be well structured as a large loop-containing bulge of the beta-sheet. The N termini of both mutants, which contribute to a large extent to the binding to the proteinase, are very flexible. A loop structure involving the residues L7 to A10 as found in related inhibitors, such as in the kininogen domains 2 and 3, is not sufficiently populated to be observed.

Amino Acid Sequence↗