Extractive Spectrophotometric Determination of Ondansetron by Ion-Pair Formation with Bromocresol Green

1996

Abstract An empirical spectrophotometric procedure for the determination of the antiemetic ondansetron is carried out. The method is based on the formation of a 1:1 ion pair with bromocresol green in the pH range over 3.2 – 4.4, extraction into chloroform layer and spectrophotometric measurement at 420.8 nm. The calibration graph is linear over the range 0.1 – 20 μg ml−1 ondansetron, with a relative standard deviation of 2.7%; the influence of foreign substances is also studied. The method is applied to ondansetron determination in human urine.

Reperfusionsschock nach okklusion der A. mesenterica superior und akkumulation von leukozyten innerhalb der d�nndarmwand

1996

Der Epithelschaden und die Leukozytenakkumulation in der Wand des Ileums nach Ischamie und Reperfusion wurden experimentell am Schwein untersucht. Die A. mesenterica superior wurde fur 1 h (Gruppe 2; n=9), 2 h (Gruppe 3; n=6) und 3 h (Gruppe 4; n=7) abgeklemmt und 2 h reperfundiert. Die histologische Beurteilung erfolgte an Hamatoxylin-Eosin- und NaphtolAS-D-Chlorazetatesterase-gefarbten Praparaten. Es entwickelte sich ein Reperfusionsschock in Abhangigkeit von der Ischamiedauer. Nach lstundiger Ischamie stabilisierte sich der Blutdruck mit erniedrigten Werten sowie einer Normalisierung des Serumlaktatspiegels und des intramuralen pHi des Dunndarms. Eine Verlangerung der Ischamie auf 2 h (G…

Difference in the behavior of methyl (S)-?-bromopropionate in its addition to trimethylvinylsilane depending on the method of initiation

1996

The addition of methyl (S)-2-bromopropionate to trimethylvinylsilane initiated by systems based on iron pentacarbonyl affords a racemic adduct and is accompanied by racemization of the unreacted chiral ester. In the presence of benzoyl peroxide, the reaction proceeds similarly, but no racemization of the starting chiral ester occurs.

Phenotypic characterization of Vibrio vulnificus biotype 2, a lipopolysaccharide-based homogeneous O serogroup within Vibrio vulnificus.

1996

In this study, we have reevaluated the taxonomic position of biotype 2 of Vibrio vulnificus. For this purpose, we have biochemically and serologically characterized 83 biotype 2 strains from diseased eels, comparing them with 17 biotype 1 strains from different sources. Selected strains were also molecularly analyzed and tested for eel and mouse pathogenicity. Results have shown that biotype 2 (i) is biochemically homogeneous, indole production being the main trait that distinguishes it from biotype 1, (ii) presents small variations in DNA restriction profiles and outer membrane protein patterns, some proteins being immunologically related to outer membrane proteins from biotype 1, (iii) ex…

Correlation of Pharmacological Properties of a Group of Hypolipaemic Drugs by Molecular Topology

1996

Abstract This investigation was undertaken to test the ability of the molecular connectivity model to predict the percentage of plasma protein binding, the percentage of total cholesterol reduction and oral LD50 in rats of a group of hypolipaemic drugs using multi-variable regression equations with multiple correlation coefficients, standard error of estimate, degrees of freedom, F-Snedecor function values, Mallow's CP and Student's t-test as criteria of fit. Regression analyses showed that the molecular connectivity model predicts these properties. Corresponding stability (cross validation) studies were made on the selected prediction models which confirmed their goodness of fit. The resul…

Zircon dating of North Bohemian granulites, Czech Republic: Further evidence for the Lower Carboniferous high-pressure event in the Bohemian Massif

1996

U-Pb zircon and rutile multigrain ages and 207Pb/206Pb zircon evaporation ages are reported from high-pressure felsic and metapelitic granulites from northern Bohemia, Czech Republic. The granulites, in contrast to those from other occurrences in the Bohemian Massif, do not show evidence of successive HT/MPLP overprints. Multigrain size fractions of nearly spherical, multifaceted, metamorphic zircons from three samples are slightly discordant and yield a U-Pb Concordia intercept age of 348 ± 10 Ma, whereas single zircon evaporation of two samples resulted in 207Pb/206Pb ages of 339 ± 1.5 and 339 ± 1.4 Ma, respectively. A rutile fraction from one sample has a U-Pb Concordia intercept age of …

Ewald Hering und die Gegenfarbtheorie

1996

Ewald Hering's color-opponent-theory is still considered one of the foundations of the visual sciences. Prior to Hering, Hermann v. Helmholtz introduced a theory of color appearance, which was based primarily on the physical aspects of the stimulus. In contrast to Helmholtz, Hering's theory strongly emphasized the subject's perception of color. As a consequence, Hering considered Helmholtz' theory inadequate. Contrary to some historical accounts, he did not object to Helmholtz's three-receptor explanation for color-mixture. Instead of Helmholtz' fundamental colors red, green, and blue, Hering suggested that the colors possess opponent character: blue-yellow; red-green; and, black-white. Hel…

Inhibition of FcεRI-mediated Activation of Rat Basophilic Leukemia Cells by Clostridium difficile Toxin B (Monoglucosyltransferase)

1996

Abstract Treatment of rat basophilic leukemia (RBL) 2H3-hm1 cells with Clostridium difficile toxin B (2 ng/ml), which reportedly depolymerizes the actin cytoskeleton, blocked [3H]serotonin release induced by 2,4-dinitrophenyl-bovine serum albumin, carbachol, mastoparan, and reduced ionophore A23187-stimulated degranulation by about 55-60%. In lysates of RBL cells, toxin B 14C-glucosylated two major and one minor protein. By using two-dimensional gel electrophoresis and immunoblotting, RhoA and Cdc42 were identified as protein substrates of toxin B. In contrast to toxin B, Clostridium botulinum transferase C3 that selectively inactivates RhoA by ADP-ribosylation did not inhibit degranulation…

Tirant: A new retrotransposon-like element inDrosophila melanogaster

1996

In this paper we report a new retrotransposon-like element of Drosophila melanogaster called Tirant. This sequence is moderately repeated in the genome of this species and it has been found to be widely dispersed throughout its distribution area. From Southern blot and in situ analyses, this sequence appears to be mobile in D. melanogaster, since its chromosome location and the hybridization patterns vary among the different strains analyzed. In this way, partial sequencing of Tirant ends suggests that it is a retrotransposon, since it is flanked by two LTRs. The presence of sequences homologous to Tirant has been also investigated in 28 species of the genus Drosophila by means of Southern …

Space–bandwidth product of optical signals and systems

1996

The space–bandwidth product (SW) is fundamental for judging the performance of an optical system. Often the SW of a system is defined only as a pure number that counts the degrees of freedom of the system. We claim that a quasi-geometrical representation of the SW in the Wigner domain is more useful. We also represent the input signal as a SW in the Wigner domain. For perfect signal processing it is necessary that the system SW fully embrace the signal SW.

On quotients of K�the sequence spaces of infinite order

1996

Toxicity of Dimethoate to Some Soil Animal Species in Different Soil Types

1996

Toxicity of dimethoate (insecticide) to an earthworm (Aporrectodea caliginosa tuberculata), a collembola (Folsomia candida), and an enchytraeid worm (Enchytraeus crypticus/variatus) was studied in three different soil types (artificial soil, clayey soil, and humus sandy soil). Parameters measured were survival and biomass change of the earthworms and survival and reproduction of the collembolas and enchytraeids. The degradation of dimethoate was analyzed too. Toxic effects were observed at the concentrations of some mg/kg dry soil. The biomass reduction of the earthworms occurred at lower concentrations than reduction in survival. The collembolas were more susceptible to dimethoate than the…

[Apoptosis of human leukemic cells induced by topoisomerase I and II inhibitors].

1996

International audience; Comparison between five human leukemic lines (BV173, HL60, U937, K562, KCL22) suggest that the main determinant of their sensitivity to topoisomerase I (camptothecin) and II (VP-16) inhibitors is their ability to regulate cell cycle progression in response to specific DNA damage, then to die through apoptosis: the more the cells inhibit cell cycle progression, the less sensitive they are. The final pathway of apoptosis induction involves a cytoplasmic signal, active at neutral pH, needing magnesium, sensitive to various protease inhibitors and activated directly by staurosporine. Modulators of intracellular signaling (calcium chelators, calmodulin inhibitors, PKC mod…

Meningitis due to Pseudomonas stutzeri in a patient infected with human immunodeficiency virus.

1996

Role of insulin-like growth factors in autocrine growth of human retinoblastoma Y79 cells.

1996

In this study, we have demonstrated that human retinoblastoma Y79 cells produce insulin-like growth factors (IGFs) type I and type II and release them into the medium. We have also ascertained, by means of competitive studies and cross-linking procedure, that Y79 cells contain the type-I IGF receptor (IGF-IR). Furthermore, surface-bound IGF-I is internalised by the receptor, then degraded to amino acids. Insulin, IGF-I and IGF-II caused down-regulation of IGF-IR; the effect is concentration and time dependant. Scatchard analysis demonstrated that incubation with insulin markedly decreased the binding capacity measured for IGF-I while the apparent Kd value calculated for IGF-I binding was no…

Cytogenetic analysis of three primary Bellini duct carcinomas.

1996

Three Bellini duct carcinomas (BDC) of the kidney were cytogenetically analyzed after short-term culture. All three had clonal chromosome abnormalities: 91-92,XXY,-Y, +12, +12, -15, -16, -18, +mar (case 1); 53,XY, +2,t(2;7)(p22;q11), +der (2)t (2;7)(p22;q11), +3, +r(3),add(5)(p15), +7, -8, +12, +17, +r(17), +20, -21 (case 2); and 44-47,X,-Y, +9, +16, -21/46,XY. Some of the numerical abnormalities are shared with papillary renal cell carcinomas (PRCC)(+7, +12, +16, +17, and +20) but not with transitional renal cell carcinomas. The present findings support the previous notion that BDC are different from other types of RCC.

Humanα1-Antitrypsin Gene Transfer toIn VivoMouse Hepatocytes

1996

ABSTRACT The in vivo gene transfer to mouse hepatocytes of pTG 7101, a plasmid containing the full-length gene encoding human α1-antitrypsin (α1-AT) DNA, has been studied by iv administration of recombinant DNA (100 ng/mouse) encapsulated in large and small liposomes. Our results from immunohistochemical liver sections and cytophotometric analysis of hepatocyte chromophore absorbance indicate that human α1-AT was expressed in liver parenchymal cells from mice treated (48 hr before) with DNA encapsulated in small liposomes, and this effect remained for at least 2 weeks. In contrast, the efficiency was greatly limited when large liposomes were used as a vehicle for gene transfer. Additional e…

On Transition Structures for Hydride Transfer Step: A Theoretical Study of the Reaction Catalyzed by Dihydrofolate Reductase Enzyme

1996

Abstract A theoretical study is presented of the catalytic mechanism of dihydrofolate reductase (DHFR) enzyme based upon the characterization of the transition structure (TS) for the hydride transfer step. Analytical gradients at AM1 and PM3 semiempirical levels have been used to characterize the saddle point of index one (SPi-1) on global energy hypersurface for the hydride transfer in the active site of DHFR enzyme. The geometry, stereochemistry, electronic structure, and transition vector (TV) components associated to SPi-1 are qualitatively computational level independent. The TV amplitudes show primary and secondary isotope effects to be strongly coupled. The geometrical arrangement of…

Cytokine production pathway in the elderly.

1996

It is well known that aging is associated with various alterations in lymphoid cell functions, particularly with a progressive decline in immune responsiveness to exogenous antigens and increasing incidence of autoimmune phenomena. Many studies have been focused on the mechanisms of the immunologic features of aging. this review describes our results of studies performed to determine the influence of age on the capacity to produce interleukin-2 (IL-2), interferon-gamma (IFN-gamma), interleukin-4 (IL-4), interleukin-t (IL-5), interleukin-6 (IL-6) and tumor necrosis factor (TNF). Mitogen-stimulated cultures of mononuclear cells (MNC) from human beings were assessed for cytokine-producing capa…

Transient solutions for temperature and pressure waves in fluid-saturated porous rocks

1996

SUMMARY In this paper, hot-fluid migration dynamics for a fluid-saturated porous rock is analysed theoretically. We first recall a Bonafede model implemented with a classical scale analysis; this allows us to discuss a fully non-linear formulation related to transient phenomena, which is solved analytically as a solitary shock wave. The resulting time-scales are particularly small, corresponding to intense short-time geothermal phenomena. A novel non-linear migration mechanism, related to Darcy convection, is also discussed.

Carrier-dependentT c -suppression in Cu-site substituted high-T c cuprates

1996

We studied theTc-suppression by Cu-site substitution in Bi2Sr2Ca1−xYx(Cu1−zMz)2O8+δ (Bi-2212) with M=Fe, Co, Ni, Zn and in Bi2Sr1.6La0.4Cu1−zMzO6+δ (Bi-2201) with M=Co, Zn under variation of the hole concentrationp. We found a distinct behaviour between the underdoped and overdoped side of theTc-p phase diagram. Only in the overdoped regime,Tc is scaling asTc(p,z)=Tc(p,0)g(z) with ap-independent scaling functiong(z). We demonstrate the universality of this distinction in p-type high-Tc cuprates by comparison with publications on the La-214 and Y-123 systems and apply the scaling law to compare Bi2Sr2Ca(Cu1−zCoz)2O8+δ with the intercalation compound IBi2Sr2Ca(Cu1−zCoz)2O8+δ. The results are …

Formation of dislocation patterns: Computer simulations

1996

Dislocations patterns have been extensively studied by means of TEM. In parallel, theoretical approaches have been developed by using two methods; reaction diffusion schemes and computer simulation models. This distinction is not rigid since some computer models include the former approach in their evolution equations. Independently from the difficulties each approach presents in formulating the collective behavior of dislocations, the aim of these studies is to exhibit simple dislocation patterns as persistent slip bands and/or cellular organization. In this context, computer simulations brought a methodology which undoubtedly is a complement to the existing approaches for dislocations. Ne…

Cyclosporin- and nifedipine-induced gingival overgrowth in renal transplant patients: correlations with periodontal and pharmacological parameters, a…

1996

The factors associated with cyclosporin A (CsA)- and nifedipine (Nif)-induced gingival overgrowth were investigated in 113 renal transplant recipients receiving CsA alone (Group 1) [n = 61], CsA and Nif (Group 2) [n = 28], or azathioprine (Aza) (Control Group) [n = 24]. Periodontal and pharmacological parameters were assessed for each patient. The patients with a gingival overgrowth index (GOI) score1 were considered responders (R); those with a score/= 1 were non-responders (NR). Gingival overgrowth occurred in 33.7% of the patients in Groups 1 and 2; 60% of the responders were receiving CsA+Nif. In R, no relationship was found between the GOI and the periodontal and pharmacological parame…

UDP-glucose deficiency in a mutant cell line protects against glucosyltransferase toxins from Clostridium difficile and Clostridium sordellii.

1996

Abstract We have previously isolated a fibroblast mutant cell with high resistance to the two Rho-modifying glucosyltransferase toxins A and B of Clostridium difficile. We demonstrate here a low level of UDP-glucose in the mutant, which explains its toxin resistance since: (i) to obtain a detectable toxin B-mediated Rho modification in lysates of mutant cells, addition of UDP-glucose was required, and it promoted the Rho modification dose-dependently; (ii) high pressure liquid chromatography analysis of nucleotide extracts of cells indicated that the level of UDP-glucose in the mutant (0.8 nmol/106 cells) was lower than in the wild type (3.7 nmol/106 cells); and (iii) sensitivity to toxin B…

The multixenobiotic resistance mechanism in the marine sponge Suberites domuncula: its potential applicability for the evaluation of environmental po…

1996

Experiments were carried out with the marine sponge Suberites domuncala to determine whether sponges may express - like mammalian tumor cells a multidrug-like transporter system. The results demonstrate that sponge cells possess such a protective system termed multixenobiotic resistance (MXR) pump or P-glycoprotein-like pump, The protein was identified by antisera for the mammalian P170 multidrug resistance protein as a 130 kDa molecule, Binding studies were performed with H-3-vincristine (H-3-VCR) and membrane vesicles ; this process is ATP-dependent and inhibited by verapamil, which is known to reverse the multidrug-resistance phenotype in mammalian systems, Accumulation experiments were …

Siderophore-mediated iron acquisition mechanisms in Vibrio vulnificus biotype 2

1996

Vibrio vulnificus biotype 2 is a primary pathogen for eels and, as has recently been suggested, an opportunistic pathogen for humans. In this study we have investigated the ability of V. vulnificus biotype 2 to obtain iron by siderophore-mediated mechanisms and evaluated the importance of free iron in vibriosis. The virulence degree for eels was dependent on iron availability from host fluids, as was revealed by a reduction in the 50% lethal dose for iron-overloaded eels. This biotype produced both phenolate- and hydroxamate-type siderophores of an unknown nature and two new outer membrane proteins of around 84 and 72 kDa in response to iron starvation. No alterations in lipopolysaccharide …

Phage types and ribotypes of Salmonella enteritidis in southern Italy.

1996

Differently from other European countries, Southern Italy was affected by a considerable increase in human infections due to Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) only after 1990. On the present investigation, two groups of S. Enteritidis strains isolated during the low-incidence period 1980-1984 and the epidemic period 1990-1993, respectively, have been submitted to phage-typing and ribotyping in order to ascertain whether the epidemic increase was determined by the spread of a foreign bacterial clone or not. Among the 150 isolates relative to the aforesaid two periods, 12 different phage types (PTs) were observed. PT4 was the most common phage type among…

FAST OSCILLATING MIGRATIONS IN A PREDATOR-PREY MODEL

1996

The aim of this paper is to give a method which permits us to describe how individual properties can emerge at the population level, in population dynamics. We consider interacting populations. In order to take into account the spatial or behavioral heterogeneity, we subdivide each population into subpopulations. A given subpopulation corresponds to those individuals having the same behavior and who are in a homogeneous environment. Furthermore, we assume that the migration process is faster than the growth and interaction processes. Therefore, we must study models with many variables coupled together into large scaled differential systems. Firstly, our method permits us to reduce these co…

Determinants of homonym and synonym rates of record linkage in disease registration.

1996

AbstractReliable record linkage is an essential component of the quality of population-based disease registration. Quality assessment of disease registries should, therefore, include quantitative approaches to describe the extent of record-linkage errors. The homonym and synonym rates have been proposed for this purpose. The homonym rate quantifies the proportion of distinct patients excluded from registration due to erroneous linkage with other patients. The synonym rate quantifies the proportion of unrecognized duplicate notifications on patients already registered in the registry. This paper provides an algebraic assessment of the determinants of both rates. It is shown how the homonym a…

Gastroesophageal reflux and cow's milk allergy in infants: A prospective study

1996

Recent reports have suggested that gastroesophageal reflux in pediatric patients may be caused by food allergy.The aim of our study was to determine the frequency of the association of gastroesophageal reflux with cow's milk protein allergy in patients win the first year of life.We studied 204 consecutive patients (median age, 6.3 months) who had been diagnosed as having gastroesophageal reflux on the basis of 24-hour continuous pH monitoring and histologic examination of the esophageal mucosa.Clinical history suggested diagnosis of cow's milk allergy in 19 infants, and 93 others had positive test results (serum IgE anti-lactoglobulin, prick tests, circulating or fecal or nasal mucus eosino…

Characterization of wine yeast strains of the Saccharomyces genus on the basis of molecular markers: Relationships between genetic distance and geogr…

1996

Summary We identify and characterize 31 Saccharomyces strains from different wine regions, deposited at the Spanish Type Culture Collection, according to mtDNA restriction patterns and chromosomal profiles. By using this kind of information we analyze the correlation between genetic distances and ecological or geographical factors by means of a cluster analysis, assessed by an analysis of the molecular variance (AMOVA). From these analyses, red wine strains are significantly grouped according to their geographic origin, independently of the wine type and the grapevine cultivar, and white wine strians according to ecological factors (wine type of grapevine cultivars). This study also confirm…

Multiple-chromosome sex systems in the darkling beetles Blaps gigas and Blaps gibba (Coleoptera, Tenebrionidae)

1996

We have studied mitotic and meiotic chromosomes in the males of two species of Blaps: B. gigas and B. gibba. Karyological characteristics such as the occurrence of a multivalent configuration at diakinesis and two types of metaphase-II spreads support the notion that multiple-chromosome sex systems involving five chromosomes in B. gigas and eight chromosomes in B. gibba have developed in these species. Results obtained by means of silver staining and C-banding techniques suggest that the complex sex systems occurring in B. gigas and B. gibba may have originated from exchanges of terminal ribosomal genes among the Y chromosome and some autosomes.

Ein poröses Zirconiumoxophosphat sehr hoher Oberfläche durch eine tensidunterstützte Synthese

1996

Functional, Biochemical, and Morphological Hepatobiliary Effects in Rats Chronically Exposed to a Steroidal Antiandrogen

1996

Abstract Yellow–brown deposits in intrahepatic bile ducts and portal macrophages were observed for male, but not female, Sprague–Dawley rats fed zanoterone, a steroidal antiandrogen, for ≥3 months. The lesion did not affect biliary canaliculi and was associated with changes of biliary epithelium, portal chronic inflammation, and bile duct proliferation. Deposit formation was assumed to be related to a gender-related anomaly in bile composition and/or flow. Therefore, the pathogenesis of the lesion was investigated in male, female, and orchiectomized rats. Hepatobiliary structure and function were evaluated after 3 months of treatment and 3 months of reversibility. Drug biliary disposition w…

EFFECTS OF CYCLOPROPENOID FATTY ACIDS (BAOBAB SEED OIL) ON THE FATTY ACID PROFILE OF LIPIDS FROM DIFFERENT TISSUES IN THE RAT

1996

Rats were fed for 8 weeks a diet containing either Baobab seed oil (FBO) rich in cyclopropenoid fatty acids (CPFA) or heated oil (HBO) devoid of CPFA. In FBO rats, compared to controls (CO), the monounsaturated fatty acid content of adipose tissue lipids, liver triacylglycerols, liver and adrenal cholesteryl esters and liver, kidney, adrenal phospholipids were highly decreased to the benefit of saturated fatty acid content. In cholesteryl esters and phospholipids, the arachidonic acid (20:4 n-6) content was markedly decreased, especially in adrenals. In adrenal cholesteryl esters, adrenic acid (22:4 n-6) content was decreased more than its precursor. The effects of HBO on the tissue lipid f…

Status of independent yield measurements

1996

Recent progress in the measurement of independent yields in low energy nuclear fission is presented. Different experimental approaches are discussed and a survey of the most important experimental results obtained is given. Physical consequences for the understanding of the fission process are briefly referred.