Showing papers by "University of Zagreb published in 1992"

NADH-dependent oxidoreductase (diaphorase) activity and isozyme pattern of sperm in infertile men.

Abstract: Diaphorase activities were measured in spermatozoa from 104 infertile men. The relationships between enzyme activity, sperm characteristics (density, motility, viability), and distribution of electrophoretic patterns were examined. There was a highly significant difference (p less than .001) between the sperm diaphorase activities in specimens with sperm concentration above 40 million per milliliter (0.685 +/- 0.5 mIU/10(6) sperm; n = 57) when compared with the diaphorase values of the oligospermic specimens with sperm density below 40 million per milliliter (1.53 +/- 1.5 mIU/10(6) sperm; n = 47). However, there was no evidence to support any relationship between sperm diaphorase activities, sperm motility, viability, and the distribution of three diaphorase electrophoretic patterns. This indicates that these parameters do not account for the differences between the diaphorase activity of spermatozoa of infertile men with sperm concentrations below and those above 40 million per milliliter.

The Distance Matrix in Chemistry

Abstract: The graph-theoretical (topological) distance matrix and the geometric (topographic) distance matrix and their invariants (polynomials, spectra, determinants and Wiener numbers) are presented. Methods of computing these quantities are discussed. The uses of the distance matrix in both forms and the related invariants in chemistry are surveyed. Special attention is paid to the 2D and 3D Wiener numbers, defined respectively as one half of the sum of entries in the topological distance matrix and the topographic distance matrix. These numbers appear to be very valuable molecular descriptors in the structure property correlations.

New scoring system for prediction of ovarian malignancy based on transvaginal color Doppler sonography.

Abstract: The goal of this prospective study was to develop a new scoring system using transvaginal color and pulsed Doppler characterization of ovarian lesions. Transvaginal color Doppler sonography was performed on 812 women, among whom 174 adnexal masses were found and analyzed. Ovarian lesions were assessed by means of morphological and color Doppler scoring systems. Tumors were characterized ultrasonically as benign or suspected of being malignant. Scoring system results were correlated with histopathological findings. Among our study group, 38 malignant and 136 benign ovarian tumors were found and verified. The color Doppler scoring system was very useful in distinguishing benign from malignant masses, with a sensitivity of 97.3% and a specificity of 100%, compared with the morphological scoring system's sensitivity of 92.1% and specificity of 94.8%. We also evaluated a combination of both scoring systems. We believe that new color Doppler scoring system maximizes the ability to discriminate between benign and malignant entities.

The assessment of benign uterine tumor vascularization by transvaginal color Doppler.

Abstract: Transvaginal color flow Doppler was used to study uterine flow and fibroid arterial supply. These studies were carried out in 101 patients with palpable uterine fibroids and 60 women attending the clinic for annual checkups. Blood flow impedance expressed as resistance index (RI), pulsatility index (PI), and blood velocity are calculated from the 5th to the 8th day of the menstrual calendar. Increased blood velocity and decreased RI and PI in both uterine arteries occurred in patients with uterine fibroids. The same technique was also used to study blood flow in the main arteries supplying identifiable fibroid. Diastolic flow in these arteries was always present and increased in comparison with uterine artery blood flow. The difference in uterine artery blood flow between patients with fibroids and healthy volunteers is statistically significant and may have predictable value in growth rate evaluation of the benign uterine mass.

Application of mass titration to the point of zero charge determination

Abstract: The mass titration method for determination of the zero point of charge (PZC) was proposed by Noh and Schwarz (J. Colloid Interface Sci. 130, 157 (1989)). This method was developed for (hydr)oxides and is limited to pure samples. It is based on the fact that pH approaches the limiting value (pH∞) by addition of solid powder to an aqueous medium. The limiting pH∞ value, at a high solid content, is then equal to pHpzc. This article is an extension of the original work and concerns the samples contaminated with an acid or base which are not irreversibly bound

Tumoricidal Activation of Murine Resident Peritoneal Macrophages by Interleukin 2 and Tumor Necrosis Factor α

Abstract: The capacity of recombinant human interleukin 2 (rH-IL2), alone or in combination with recombinant tumor necrosis factor (r-TNF alpha), to activate murine resident peritoneal macrophages to a tumoricidal state was examined. Resident peritoneal exudate cells from C57BL/6 mice were cultured for 18 h with activating agents and washed and the adherent cells (macrophages) were assessed for cytolytic activity against radiolabeled target tumor cells (EL4, P815). Under these conditions, rH-IL2 alone activated macrophages to a tumoricidal state in a concentration dependent fashion. Neither murine nor human r-TNF alpha alone had any activating effect but, when combined with rH-IL2, further stimulated rH-IL2-inducible responses. Using polymyxin B, it was shown that macrophage activation was not due to an inadvertent lipopolysaccharide contamination of the r-TNF alpha or rH-IL2 preparations. It was also unlikely that target cell lysis was a direct result of increased TNF alpha production by rH-IL2 stimulated macrophages since P815 is totally resistant to lysis by r-TNF alpha. Although the lytic effector function was mediated by adherent cells, nonadherent peritoneal exudate cells were required for activation to occur. Furthermore, antisera against murine gamma-interferon, when added to activation cultures, reduced the level of cytolytic activity which developed. These data suggest that rH-IL2-induced peritoneal macrophage activation requires stimulation of nonadherent cells and is dependent upon gamma-interferon mediated mechanisms.

Urinary excretion of diethylphosphorus metabolites in persons poisoned by quinalphos or chlorpyrifos

Abstract: The urinary excretion rates of diethyl phosphate and diethyl phosphorothioate and changes in blood cholinesterase activities were studied in fifteen persons self-poisoned either by the organophosphorus pesticide quinalphos (twelve persons) or by chlorpyrifos (three persons). The organophosphate poisoning was always indicated by a significant depression of serum and/or red blood cell cholinesterase activities. The return of serum cholinesterase activity in the range of referent values took more than 30 days and had a different course in different persons. The most rapid increase in red blood cell acetylcholinesterase activity was noted within 24 h after the first treatment with oximes Pralidoxime and/or HI-6. None of the spot urine samples, collected daily after admission of persons to hospital, contained measurable quantities of the parent pesticide. There was no correlation between the maximum concentration of total urinary diethylphosphorus metabolites normalized to creatinine and the initial inhibition of blood cholinesterase activities measured in samples collected on the day of admission to hospital. The excretion of metabolites followed the kinetics of a biphasic reaction. The half-time of urinary metabolites concentration decrease in the fast excretion phase in quinalphos poisoned persons was 5.5–14.2 h (eight persons) and 26.8–53.6 h (four persons) and in chlorpyrifos poisoned persons 3.5–5.5 h. The half-time for the slow excretion phase ranged from 66.5 to 127.9 h in all persons and for both compounds. For a given person, the rates of excretion of diethyl phosphate and diethyl phosphorothioate were about the same. However, in quinalphos poisoned persons the proportions of single metabolites in total diethylphosphorus metabolites varied with the initial maximum concentration of total metabolites. Simultaneous determination of both metabolites gave a more reliable and sensitive confirmation of absorption and retention of quinalphos and chlorpyrifos in the body.

Chemical and electrochemical characterization of chemically synthesized conducting polypyrrole

Abstract: The conducting polypyrrole chemically synthesized in water, using the variable concentrations of FeCl3 and CuCl2 as oxidizing agents, was chemically and electrochemically characterized and compared with electrochemically generated polypyrrole. According to the results of elemental analysis and counter ion determinations, it can be concluded that a mixture of dimer and trimer was obtained using CuCl2, i.e., a dimer composition using FeCl3 as an oxidant. Cyclic voltammetric studies of polypyrrole obtained by using FeCl3 as an oxidant showed no evidence of polypyrrole decomposition after repetitive cycling. The voltammograms showed also that after the oxidation reaction a high capacitive current remained, confirming the assumption that the capacitive current is intrinsically associated with polypyrrole, irrespective of the way of its preparation. Cyclic voltammogram of the polypyrrole synthesized by oxidation with CuCl2 showed different shape, probably influenced by the presence of copper ions incorporated in polymers. © 1992 John Wiley & Sons, Inc.

Asymmetry of the root canal foramen

Abstract: Deviation of the major apical foramen from the anatomical root apex is a recognized phenomenon. To determine the frequency, position and mean distance of the major apical foramen from the anatomical root apex, 230 roots of permanent teeth were examined stereomicroscopically and radiographically. Radiographic analysis was used to establish how accurate the conventional radiograph was in displaying such a deviation. The frequency of deviation of the major foramen, determined stereomicroscopically, was 76%, and depended on the type of teeth examined. Radiographic analysis of the same sample revealed 57% of root canals had asymmetry of the root canal foramen. Agreement of stereomicroscopic and radiographic findings was found to be 61%. The most frequent deviation of the major foramen was on the distal root surface (29%), but this was not statistically significant. The mean distance between the deviation of the major foramen and the anatomical root apex was 0.99 mm. The study indicates that the clinician should consider deviation of the foramen during root canal treatment, as the deviation could not easily be detected radiographically.

Engineering approach to mixing quantification in bioreactors

Abstract: “Homogeneity-time” is defined and introduced as the criterion for mixing quality in bioreactors. The criterion could replace the mixing time, in the case, when more than one measuring point (sensors) is included in the measuring system. Results based on the homogeneity-time and the temperature pulse method, achieved in stirred tank reactors under aerated conditions as well as in a jet-mixed tank, are presented.

Predicting Behavior of High and Low Self-Monitors: An Application of the Theory of Planned Behavior

Abstract: Using Ajzen's theory of planned behavior, behavioral intentions, attitudes, subjective norms, and perceived behavioral control were assessed for 24 high and for 29 low self-monitors. In addition, behavior (attendance at class lectures) was unobtrusively recorded. Intentions were best predicted by attitudes of the low and by subjective norms of the high self-monitoring groups. Low self-monitors' overt behavior was predicted by intentions, and high self-monitors' behavior by the interaction of intention × perceived behavioral control.

Electrochemical methods in the study of localized corrosion attack

Abstract: Electrochemical methods for determining the characteristic pitting potentials of 90Cu−10Ni alloy in slightly alkaline chloride solutions are summarized and the results of measurements carried out using potentiostatic, quasi-potentiostatic, potentiodynamic and galvanostatic techniques, complemented byex situ techniques — SEM and EDXA — are discussed. In borate buffer solution a passive state is established due to the formation of the oxide film with low ionic conductivity. However, in the presence of Cl− ions, at potentials higher than a certain critical value, breakdown of the anodic passivity occurs, caused by field-stimulated chloride entry into the passive oxide film at singular point defects. The brightening of the pits formed after oxide film breakdown was established to be due to the conversion of the passivating oxide film to one of high ion conductivity “Contaminated oxide” permits the passage of the metal cation into and through it, finally leaving it at the film/solution interface where pitting can proceed. During localized attack two characteristic potentials have to be distinguished: the potential of pit nucleation,E n, above which pit nucleation starts, and the breakdown potential,E b, above which the growth of nucleated pits develops. An attempt is made to compare the values ofE n andE b obtained through different methods, and to determine the factors influencing these values in each particular method.

Bibliography on quantum logics and related structures

Abstract: The bibliography contains 1851 references on axiomatic structures underlying quantum mechanics, with stress on varieties of algebraico-logical, probabilistic, and operational structures for which the term quantum logics is adopted. An index of about 250 keywords picked out from the titles is included and statistics about papers, journals, and authors are presented. Monographs and proceedings on the subject are noted.

Kontinuierliche Reaktionsführung mit löslichen Enzymen

Abstract: Continuous processes with soluble enzymes. This paper surveys the use of continuously operating enzyme-membrane reactors with enforced flow where the retention of soluble enzymes in the reaction vessel is achieved by means of an ultrafiltration membrane. This technique has been commercialized in the acylase process for the synthesis of L-amino acids on a 200 ton/year level. It is especially useful for the application of multi-enzyme systems with cofactor regeneration. The synthesis of L-tert-leucine from the corresponding α-keto acid has been achieved on a kilogram scale. Coenzymes coupled to water soluble polymers are retained in the membrane-reactor together with the enzymes. Use of suitable conditions prevents loss of enzyme and coenzyme by passage through the membrane or by deactivation. Therefore the costs of enzymes and coenzymes are no longer limitations for economic processes. In the continuously operating enzyme-membrane reactor regeneration of the coenzyme up to 600 000 times was achieved. In continuous peptide synthesis space-time yields of 25 kg/(l d) were obtained. To suppress side reactions very high catalyst concentrations are possible, yielding residence times below 4 min.

Glucose, insulin, HGH and IGF-I levels in maternal serum, amniotic fluid and umbilical venous serum : a comparison between late normal pregnancy and pregnancies complicated with diabetes and fetal growth retardation

Abstract: Fetal growth and development is dependent upon various growth factors such as glucose, insulin, HGH and IGF-I. These growth factors were measured in maternal serum (MS), amniotic fluid (AF) and umbilical venous serum (UV) in late gestation in normal, insulin dependent diabetic pregnancies (IDDM) and in pregnancies complicated with intrauterine growth retardation (IUGR). The UV glucose values of 1.9 +/- 0.9 mmol/L and UV insulin values of 8.0 +/- 1.8 mU/L were the lowest in IUGR pregnancies, and the highest were in UV serum from IDDM pregnancies, and the difference was statistically significant for this two groups. IGF-I values in UV indicated that there was significant difference in IGF-I concentrations when both, IUGR and IDDM groups were compared to the controls. There was a parallel shift in AF and MS glucose and insulin concentration as birthweight increased. The highest IGF-I values of 7.2 +/- 9.6 mumol/L in AF and MS were found in pregnancies with infants whose birthweight was 3500 grams and greater. Infants from pregnancies complicated with IUGR and IGF-I low values of 0.6 +/- 1.2 mumol/L in AF. HGH concentrations of 15.6 +/- 9.4 micrograms/L in UV were observed in IDDM pregnancies and significantly lower than the values in IUGR and normal pregnancies. HGH umbilical venous values decreased with duration of pregnancy and with increase in fetal size. The high HGH concentrations in the fetus and its dramatic fall after parturition, and the obtained negative correlation between HGH and IGF-I in umbilical vein may exhibit the maturation of the hypothalamic-growth hormone-IGF-I axis. It seems likely that changes in maternal serum, umbilical venous and amniotic fluid insulin-like growth factor I influence birthweight in normal and IUGR infants and in those of diabetic mothers.

Ultrasonographic guidance of needle placement for shoulder arthrography.

Abstract: We describe a technique using high resolution ultrasonography for needle placement for shoulder arthrography employing the posterior approach, which to our knowledge has not been reported previously. Twenty-four patients with clinical suspicion of rotator cuff lesion underwent shoulder arthrography under sonographic control. Patients ranged in age from 26 to 72 years (mean, 57 years). Accuracy of the needle placement using this technique was 100%. There were no injuries to adjacent structures and no extravasation outside the joint. Although fluoroscopic control of needle placement during shoulder arthrography is the technique of choice, sonographic control using the posterior approach may be useful in certain situations (e.g., if the patient is concerned about radiation dose or if there is soft tissue injury at the anterior of the shoulder.

Laser induced molar tooth pulp chamber temperature changes.

Abstract: Temperature changes in enamel tissue and the pulp chamber under the influence of a CO2 laser were measured by direct methods in vitro X-ray diffraction analysis revealed α-Ca3(P

Total body irradiation with or without lung shielding for allogeneic bone marrow transplantation.

Abstract: From June 1986 to June 1990, 64 patients with leukaemia (25 acute myelogenous leukaemia, 21 acute lymphoblastic leukaemia and 18 chronic myeloid leukaemia) undergoing marrow transplantation were randomized to receive cyclophosphamide (CY) and fractionated total body irradiation (TBI) without lung shielding (n = 33) or CY and fractionated TBI with lung shielding (n = 31, control group) as conditioning. Patients conditioned with TBI without lung shielding received a significantly higher total lung dose compared with the control group (p less than 0.0001). The 3-year leukaemia-free survival for patients receiving TBI without lung shielding is 54 +/- 18% versus 51 +/- 18% for patients receiving TBI with lung shielding (p = ns). There was no significant difference in the probability of leukaemia relapse (22 +/- 18% for TBI without lung shielding versus 24 +/- 18% for control group; p = ns). The probability of interstitial pneumonitis is 15 +/- 14% for TBI without lung shielding and 5 +/- 5% for TBI with lung shielding (p = ns). A higher incidence of lung fungal infection (15 versus 3%) and interstitial pneumonitis (12 versus 3%) has been documented in patients receiving TBI without lung shielding compared with the control group. The results indicate that higher radiation dose to the lung did not increase antileukaemic efficacy of TBI but seemed to be associated with the increased pulmonary toxicity.