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PubMed1996

Prothrombin-related antigens in human aortic intima.

Most plasma proteins are present in both normal and atherosclerotic intima, and their concentrations in intimal interstitial fluid are directly related to plasma concentration and molecular size. All intimal samples also contain soluble fibrin-fibrinogen-related antigens, consisting of variable mixtures of fibrinogen and fibrinogen and fibrin degradation products; the extracted washed tissue contains insoluble fibrin. It appears that the fibrinogen is subjected both to degradation and to conversion to fibrin, which in turn undergoes lysis. Biochemically, insoluble "fibrin" can be detected by incubating the washed tissue with plasmin, and assaying the fibrin degradation products that are released; they are released from all samples, including small amounts from normal intima. The fibrin could arise by incorporation of a mural fibrin clot and/or clotting of the fibrinogen within the intima, which contains a "cocktail" of clotting-related factors including prothrombin/thrombin-related antigens, antithrombin III (AT III), and other protease inhibitors: in recent experiments stripped intima was immediately treated with ethylenediaminetetraacetic acid, minced, extracted with Tris-buffered saline, and the extracts analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with antisera to prothrombin and AT III. Surprisingly, all blots treated with antiprothrombin antisera showed large bands migrating with free thrombin (36 to 37 kDa) and prothrombin (74 kDa) and four intermediate bands. In addition, in all 10 samples examined a band of high molecular mass (170 kDa) but variable intensity was present. This 170-kDa band comigrated with the major band reacting with anti-serum to AT III. The theoretical 1:1 thrombin:AT III complex (98 kDa) was not detected. Thus active thrombin appears to be present in intima, and this may be a highly atherogenic factor, both causing fibrin deposition and acting as a potent mitogen for arterial smooth muscle cells.

Antigens↗

PubMed2000

[Benzodiazepine prescription at a health center: prevalence, its use and user characteristics].

OBJECTIVES: To find the prevalence of prescription of benzodiazepines (BDZ) in 1997 at a health centre (HC), and the characteristics of both their consumption and the takers. DESIGN: Crossover, observational study. SETTING: Primary care urban centre. PATIENTS: From a total of 7356 patients over 14 with clinical records and belonging to four lists, a random sample stratified by lists was selected. INTERVENTION: A form was used to gather social and demographic data, educational level, family context, linked pathologies, number of visits to HC per year, BDZ prescription and variables defining the kind of consumption. MAIN RESULTS: The prevalence of BDZ prescription was 7.7% (CI, 6-10%). Consumption profile: 33% long BDZ, 31% intermediate and 33% short. 44% consumed BDZ occasionally or for less than 2 weeks, and 42% had been taking it for over a year. For 56% (95% CI, 40-70) their G.P. was the origin of the prescription. The reason for the prescription was not specified in 42% of cases. The variables which defined the profile of the consumers, included in the logistic regression, were: sex, number of visits and linked pathologies, whose OR were: 1.57 (CI, 1.08-2.03), 1.11 (CI, 1.06-1.17) and 1.61 (CI, 1.04-2.05). CONCLUSIONS: The prevalence of BDZ prescription during 1997 in the population seen at our clinics was very similar to the figures found in other studies, with higher annual consumption averages and without the reason for taking it being specified in half the cases. The profile of BDZ takers was: mainly women, people with linked pathologies, and as a function of the number of attendances.

Adult↗

PubMedDate not supplied

Ecological modelling: from the biosphere to the everyday data gathering; filling the gap.

Biosphere, according to many authors, can be considered as a system characterised by control mechanisms, which allow the maintenance of its stability. If the Biosphere is a complex object, the coming out of the equilibrium will have as a result a rapid change which cannot be controlled and whose results cannot be foresighted. Modelling is, for this reason, desperately needed. A general mathematical modelling suggested that the Biosphere evolution be characterised by periods of stability and instability, which are related to the connections between its components. These components, both living and not living, are connected by feedback relationships maintaining stability. From this model a general ecosystem modelling was developed which was first applied to a very peculiar situation i.e. that of the hydro-thermal marine vents. The hydrothermal ecosystem is, anyway, a very peculiar one and it can be considered also a micro-biosphere with its own sources of energy not related to sun radiation. For this reason it was possible to make a correlation between these very peculiar ecosystems and the Biosphere. More difficult it is to relate the modelling of the light depending ecosystems, which are, on the contrary, of great interest because they are directly linked to the Biosphere and objects of quite everyday data gathering. Usually the description of ecosystems, which is proposed by the everyday operative task of collecting data, and which represents the widest source of data for modelling, is related to the quality of waters or air. In this way we have to find tools correlating the data routinely investigated and the general model proposed. Here we present the other side of the approach, a local investigation of the qualities of water, with the hope to make a proposal for the ecologists to carry on their job also taking into consideration the problem of ecosystems modelling. An evaluation study of the environmental condition of Fine River, based on the E.B.I. method (Extended Biotic Index) applied to macroinvertebrates was carried out in 2002. Seven sampling locations were selected along the main flow and two were selected on the two most important tributaries that flow into the Fine, the Savalano and the Pesciera-Marmolaio. On the upper part of the river two locations were selected, up-river the artificial reservoir of S. Luce, and five locations were selected in the intermediate and potamal part. 43 taxa of macroinvertebrates have been detected, among them 4 Plecoptera and many Ephemeroptera assembled by environmental variables. Chironomids have been detected in all the locations. The multivariate analysis with Multidimensional Scaling (MDS) applied to the samples of the potamal part location shows variability in the macroinvertebrates assemblage. The E.B.I. method resulted in a good quality of the water on the upper part of Fine River. The E.B.I. results, corresponding to the second Quality Class (Q. C.), were determined by the presence of the Plecoptera Chloroperla and several Ephemeroptera. These taxa are considered among the most sensitive to pollution. Downriver of Santa Luce reservoir, the water condition gets worse (3rd Q. C.), and this remains consistent along the intermediate and potamal part of the river, though it is never to be considered really bad. Water quality of the Savalano results between the second and third Q. C., while the situation of the Pesciera that flows waters of really bad quality into Fine River is to be considered serious. The F7 station (Polveroni), situated at the closing section of the basin, proves to be suitable to summarise the general conditions of the river. Finally a proposal to use the model developed for the hydrothermal vents for a provisional modelling to recover the water quality in the investigated ecosystem is presented and discussed.

Animals↗

PubMed1987

[Electrophoretic pseudopolymorphism: the role of modifications illustrated by proteolysis].

The term "pseudopolymorphism" refers to a situation, where there is no simple correspondence between genotype and phenotype: a single genotype may be moulded into several phenotypes. It is known that broad substrate specificity of enzymes may be one of the causes for pseudopolymorphism. This article deals with the other cause for this phenomenon--a consequence of post-translation modifications, such as limited proteolysis. Variability of some enzymes of grass carp Ctenopharyngodon idella Val. (Pisces, Cyprinidae) was studied by gel electrophoresis. It was found that variability of isozyme patterns of lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-PDH), malic enzyme (ME) and esterase (EST) is connected with the differences in protease activity of grass carp liver homogenates. The fish isozyme patterns of high (and, partially, intermediate) proteinase activity had some anomalies: displacement of fractions, one or several additional fractions, decreased activity of single fractions or the whole spectrum. In some cases, this variability looked like a classical polymorphic system specified by two alleles of one locus. The effect of enzymes' and proteins' modifications on electrophoretical pseudopolymorphism is discussed.

Animals↗

PubMed2006

Thiopurine methyltransferase (TPMT) activity and adverse effects of azathioprine in inflammatory bowel disease: long-term follow-up study of 394 patients.

AIM: To prospectively evaluate whether a relationship between thiopurine methyltransferase (TPMT) activity and incidence of adverse effects (especially myelotoxicity) exists, in a long-term follow-up study of a large group of patients with inflammatory bowel disease treated with azathioprine. METHODS: TPMT activity in red blood cells (RBC) was measured by a radiochemical method in 394 consecutive patients with Crohn's disease (238) or ulcerative colitis (156) starting treatment with azathioprine. The relationship among several variables and TPMT values was assessed, and the correlation between such levels and the incidence of adverse effects was evaluated. RESULTS: Mean TPMT value was 18.6 +/- 4 U/mL RBCs (range 9.4-33.7). No patient had low levels (<5), 7.1% had intermediate levels (5-13.7), and 92.9% had high levels (>13.8). Differences (P < 0.001) were demonstrated in TPMT activity depending on the type of inflammatory bowel disease, but not on the remaining variables (including treatment with 5-aminosalycilates). Adverse effects were reported in 74 patients (18.8%), the most frequent being gastrointestinal intolerance (9.1%) and myelotoxicity (4.3%). No patient having adverse effects had low TPMT levels. However, mean TPMT activity was lower in those with adverse effects (16.6 +/- 3 vs 19.1 +/- 4 U/mL, P < 0.001). Moreover, the probability of suffering myelotoxicity in the high TPMT group was only 3.5%, compared with 14.3% in the TPMT intermediate group (95% CI = 1.37-14.9; OR = 4.5). CONCLUSIONS: The strategy of determining TPMT activity in all patients prior to initiating treatment with azathioprine could help to minimize the risk of myelotoxicity, as patients with intermediate TPMT activity had fourfold more risk than high TPMT activity patients.

Adult↗

PubMed1997

Effects of selection and habituation on vertical ground reaction force in greyhounds.

OBJECTIVE: To determine effect of dog selection and habituation on vertical ground reaction force variables. ANIMALS: 133 Greyhounds of either sex, weighing between 22 and 39 kg. PROCEDURE: Vertical ground reaction force variables (peak [PFz] and impulse [IFz]) for hind limbs were studied in dogs at 3 levels of habituation. Dogs of group 1 (n = 81) did not have prior experience with the gait analysis routine. Group-2 dogs (n = 52) were selected for having an amiable disposition, and were first evaluated after participating in an intermediate habituation routine (group 2a). These dogs were reevaluated after undergoing the full habituation routine (group 2b). RESULTS: 3 of the ground reaction force variable differed significantly between dogs of groups 1 and 2 (a and b). Dogs that had not been habituated to the gait analysis routine (group 1) had significantly longer stance times than did dogs that had been more carefully selected and habituated. Intradog coefficients of variation for PFz and the IFz were significantly greater in group-1 dogs. The PFz for group-2a dogs was significantly greater than that for group-1 dogs. Differences identified between groups 2a and 2b were more likely to be attributed to habituation only. These included significantly shorter stance time and lower intradog coefficient of variation for IFz in dogs having the highest level of habituation. CONCLUSION: Selection and habituation have measurable effects on vertical ground reaction force data obtained from trotting dogs. These include significantly shorter hind limb stance times, lower impulses of vertical force, with smaller coefficients of variation for peaks and impulses of vertical force within dogs. CLINICAL RELEVANCE: In controlled studies where critical decision making is based on gait analysis data, careful selection of subjects and habituation will significantly improve precision of the data and has the potential to reduce the subject or repetition sample size.

Animals↗

PubMed2005

Pharmacodynamic analysis of ceftriaxone, gatifloxacin,and levofloxacin against Streptococcus pneumoniae with the use of Monte Carlo simulation.

STUDY OBJECTIVE: To evaluate the pharmacodynamics of four intravenous antimicrobial regimens-ceftriaxone 1 g, gatifloxacin 400 mg, levofloxacin 500 mg, and levofloxacin 750 mg, each every 24 hours-against recent Streptococcus pneumoniae isolates. DESIGN: Pharmacodynamic analysis using Monte Carlo simulation. DATA SOURCE: The Surveillance Network (TSN) 2002 database. MEASUREMENTS AND MAIN RESULTS: Streptococcus pneumoniae isolates (7866 isolates) were stratified according to penicillin susceptibilities as follows: susceptible (4593), intermediate (1986), and resistant (1287). Risk analysis software was used to simulate 10,000 patients by integrating published pharmacokinetic parameters, their variability, and minimum inhibitory concentration (MIC) distributions from the TSN database. Probability of target attainment was determined for percentage of time above the MIC (%T > MIC) from 0-100% for ceftriaxone and area under the concentration-time curve (AUC):MIC ratio from 0-150 for the fluoroquinolones. For ceftriaxone, probability of target attainment remained 90% or greater against the three isolate groups until a %T > MIC of 70% or greater, and it remained 90% or greater against susceptible and intermediate isolates over the entire interval (%T > MIC 0-100%). For levofloxacin 500 mg, probability of target attainment was 90% at an AUC:MIC < or = 30, but the curve declined sharply with further increases in pharmacodynamic target. Levofloxacin 750 mg achieved a probability of target attainment of 99% at an AUC:MIC ratio < or = 30; the probability remained approximately 90% until a target of 70 or greater, when it declined steeply. Gatifloxacin demonstrated a high probability (99%) of target attainment at an AUC:MIC ratio < or = 30, and it remained above 90% until a target of 70. CONCLUSION: Ceftriaxone maintained high probability of target attainment over a broad range of pharmacodynamic targets regardless of penicillin susceptibility (%T > MIC 0-60%). Levofloxacin 500 mg maintained high probability of target attainment for AUC:MIC ratios 0-30; whereas, levofloxacin 750 mg and gatifloxacin maintained high probability of target attainment for AUC:MIC ratios 0-60. Rate of decline in the pharmacodynamic curve was most pronounced for the two levofloxacin regimens and more gradual for gatifloxacin and ceftriaxone.

Anti-Bacterial Agents↗

PubMed2003

Design of a prognostic index score for metastatic nasopharyngeal carcinoma.

The survival outcome of patients with systemic cancer differs significantly between individuals even within the same tumour type. We set out to illustrate this by analysing the factors determining survival in patients with metastatic disease from nasopharyngeal carcinoma (NPC) and to design a scoring system based on these prognostic factors. Patients referred between January 1994 and December 1999 were retrospectively analysed. Factors analysed included patient (age group, gender, performance status (BS) at diagnosis of metastases), disease (number of metastatic sites, specific metastatic sites, disease-free interval (DFI), metastases at presentation, presence of locoregional recurrence), and laboratory factors (leucocyte count, haemoglobin level, albumin level). Univariate and multivariable analyses were performed using the Cox proportion hazards model. A numerical score was derived from the regression coefficients of each independent prognostic variable. The prognostic index score (PIS) of each patient was calculated by totalling up the scores of each independent variable. Independently significant, negative prognostic factors were liver metastasis, lung metastasis, anaemia, poor PS, distant metastasis at initial diagnosis, and a DFI of <6 months. Three prognostic groups based on the PIS were obtained: (i) good risk (PIS=0-6); (ii) intermediate risk (7-10); (iii) poor risk (>or=11). The median survivals for these groups were 19.5, 10, and 5.8, months, respectively, (log rank test: P<0.0001). The variable prognosis of patients with disseminated NPC can be assessed by using easily available clinical information (patient, disease and laboratory factors). The PIS system will need to be validated on prospectively collected data of another cohort of patients.

Adult↗

PubMed1984

Variability in serologically detected male antigen titer and some resulting problems: a critical review.

Seroologically detected male antigen" (also called H-Y antigen) was first described in normal male mammals but now appears to occur in normal female mammals as well. "Serologically detected male predominant" (SDMP) antigen is a more appropriate name since the titer in normal males usually exceeds that of normal females. As we show, in each sex there is a considerable inter-individual variability in SDMP antigen titer, and in moderate-to-large size samples the low end of the male range of titers usually coincides with the high end of the female range. Several major problems arise from failure to recognize and/or to deal adequately with this normal variation in SDMP antigen titer. The chief problem is that the "controls" used (often a single individual) may be inadequate and misleading, leading to unjustified designation of samples as "positive", "negative", or even "deviant" ("intermediate", "reduced") for SDMP antigen titer. Other problems include deficiencies in technique and lack of statistical control for test and sample variability. Adequate attention to these problems, especially to the normal variability in SDMP antigen titer, could reduce the contradictions and inconsistencies which have troubled this field.

Animals↗

PubMed2003

Spectroscopic and computational studies of a Ni(+)-CO model complex: implications for the acetyl-CoA synthase catalytic mechanism.

The four-coordinate Ni(+) complex [PhTt(t)(Bu)]Ni(I)CO, where PhTt(t)()(Bu) = phenyltris((tert-buthylthio)methyl)borate (a tridentate thioether donor ligand), serves as a possible model for key Ni-CO reaction intermediates in the acetyl-CoA synthase (ACS) catalytic cycle. Resonance Raman, electronic absorption, magnetic circular dichroism (MCD), variable-temperature variable-field MCD, and electron paramagnetic resonance spectroscopies were utilized in conjunction with density functional theory and semiemperical INDO/S-CI calculations to investigate the ground and excited states of [PhTt(t)()(Bu)]Ni(I)CO. These studies reveal extensive Ni(+) --> CO pi-back-bonding interactions, as evidenced by a low C-O stretching frequency (1995 cm(-)(1)), a calculated C-O stretching force constant of 15.5 mdyn/A (as compared to k(CO)(free CO) = 18.7 mdyn/A), and strong Ni(+) --> CO charge-transfer absorption intensities. Calculations reveal that this high degree of pi-back-bonding is due to the fact that the Ni(+) 3d orbitals are in close energetic proximity to the CO pi acceptor orbitals. In the ACS "paramagnetic catalytic cycle", the high degree of pi-back-bonding in the putative Ni(+)-CO intermediate (the NiFeC species) is not expected to preclude methyl transfer from CH(3)-CoFeSP.

Acetate-CoA Ligase↗

PubMed2027

Effectiveness of high-dose versus standard-dose influenza vaccines against hospitalisation according to frailty risk: a prespecified analysis of the randomised trial DANFLU-2.

BACKGROUND: Frailty is a major risk factor for influenza-related complications and can influence vaccine effectiveness. We aimed to assess the relative vaccine effectiveness (rVE) of high-dose (HD-IIV) versus standard-dose inactivated influenza vaccine (SD-IIV) in older adults aged 65 years or older according to frailty risk. METHODS: This study was a prespecified analysis of DANFLU-2, an open-label, individually randomised trial, conducted in Denmark during three consecutive influenza seasons (2022-23, 2023-24, and 2024-25). Adults aged 65 years or older were randomised (1:1) to the HD-IIV or SD-IIV group. The primary endpoint was hospitalisation for influenza or pneumonia. Frailty was defined according to the validated Hospital Frailty Risk Score (HFRS) based on ICD-10 codes within 10 years before randomisation. Participants were stratified into three HFRS categories, namely low (<5 points), intermediate (5-15 points), and high (>15 points) frailty risk. The rVE of HD-IIV versus SD-IIV against the primary endpoint was assessed across prespecified HFRS categories and treating HFRS as a continuous variable. Pearson's chi-square test was used to compare safety events across frailty risk groups and randomisation groups. FINDINGS: Among 332 438 randomised participants (mean age 73·7 years [SD 5·8]; 161 538 [48·6%] were female), 276 173 (83·1%) had low frailty risk, 52 395 (15·8%) had intermediate frailty risk, and 3861 (1·2%) had high frailty risk. The primary endpoint of hospitalisation for influenza or pneumonia occurred in 1424 (0·5%) of 276 173 participants with low frailty risk, 761 (1·5%) of 52 395 with intermediate frailty risk, and 163 (4·2%) of 3861 with high frailty risk (relative risk [RR] for intermediate vs low frailty risk 2·8 [95% CI 2·6-3·1]; RR for high vs low frailty risk 8·2 [7·0-9·6]). HFRS as a continuous variable significantly modified the effect of HD-IIV versus SD-IIV against the primary endpoint with higher rVE estimates with increasing HFRS (pinteraction=0·020). The rVE was 0·2% (95% CI -10·8 to 10·2) among those with low frailty risk, 13·1% (-0·4 to 24·8) among those with intermediate frailty risk, and 19·9% (-10·3 to 42·1) among those with high frailty risk. No significant interaction was observed when HFRS was assessed according to the prespecified categorical frailty groups (pinteraction=0·17). The proportion of participants with at least one serious adverse event increased across frailty risk groups (13 366 [4·8%] of 275 795 for low frailty risk, 5475 [10·5%] of 52 315 for intermediate frailty risk, and 777 [20·2%] of 3850 for high frailty risk; p<0·0001), with similar proportions of serious adverse events in the HD-IIV and SD-IIV groups for each frailty risk group. INTERPRETATION: Among adults aged 65 years or older in Denmark, frailty risk might modify the effects of HD-IIV versus SD-IIV against hospitalisation for influenza or pneumonia, with higher rVE estimates with increasing frailty risk. These findings might support considering high-dose influenza vaccines for frail older adults. However, effect modification was not evident when frailty was assessed using prespecified categorical subgroups, and subgroup-specific estimates were imprecise, with 95% CIs crossing the null. These results should be considered exploratory, warranting further investigation. FUNDING: The DANFLU-2 trial was funded by Sanofi.

Journal Article↗

PubMed1992

Suppression of chaos and other dynamical transitions induced by intercellular coupling in a model for cyclic AMP signaling in Dictyostelium cells.

The effect of intercellular coupling on the switching between periodic behavior and chaos is investigated in a model for cAMP oscillations in Dictyostelium cells. We first analyze the dynamic behavior of a homogeneous cell population which is governed by a three-variable differential system for which bifurcation diagrams are obtained as a function of two control parameters. We then consider the mixing of two populations behaving in a chaotic and periodic manner, respectively. Cells are coupled through the sharing of a common chemical intermediate, extracellular cAMP, which controls its production and release by the cells into the extracellular medium; the dynamics of the mixed suspension is governed by a five-variable differential system. When the two cell populations differ by the value of a single parameter which measures the activity of the enzyme that degrades extracellular cAMP, the bifurcation diagram established for the three-variable homogeneous population can be used to predict the dynamic behavior of the mixed suspension. The analysis shows that a small proportion of periodic cells can suppress chaos in the mixed suspension. Such a fragility of chaos originates from the relative smallness of the domain of aperiodic oscillations in parameter space. The bifurcation diagram is used to obtain the minimum fraction of periodic cells suppressing chaos. These results are related to the suppression of chaos by the small-amplitude periodic forcing of a strange attractor. Numerical simulations further show how the coupling of periodic cells with chaotic cells can produce chaos, bursting, simple periodic oscillations, or a stable steady state; the coupling between two populations at steady state can produce similar modes of dynamic behavior.

Journal Article↗

PubMedDate not supplied

Molecular variability of TLS-CHOP structure shows no significant impact on the level of adipogenesis: a comparative ultrastructural and RT-PCR analysis of 14 cases of myxoid/round cell liposarcomas.

A specific TLS-CHOP fusion gene derived from the t(12;16) is present in at least 95% of myxoid/round cell liposarcomas (MLS). Rare cases of MLS show a variant t(12;22) translocation, resulting in EWS-CHOP fusion gene. The CHOP gene encodes a leucine-zipper transcription factor, which is implicated in both oncogenic transformation and inhibition of adipogenesis. To examine whether the molecular variability of TLS-CHOP or EWS-CHOP fusion transcript structure is associated with the degree of inhibition of adipogenesis, a comparative ultrastructural and RT-PCR-based analysis of 14 MLS was performed. The specimens consisted of 9 primary, 2 locally recurrent tumors, and one representative sample each from 3 patients with multifocal soft tissue metastases. Histologically, there were 8 high-grade and 6 low-grade MLS using 5% round cell (RC) component as the cutoff point. By RT-PCR assay there were 13 cases with TLS-CHOP fusion transcripts: 7 cases of type 5-2 (known as type II), 4 cases of type 7-2 (known as type I),1 case of type 8-2 (known as type III), and 1 unique case of type 6-2. The remaining 1 case showed an EWS-CHOP fusion transcript. Ultrastructural examination revealed that tumor cells were composed of a moderate-to-predominant proportion of well-formed lipoblasts in 4 cases, while in 6 cases such lipoblasts were very scant. The remaining 4 tumors were arrested in the stage of transitional cells. The heterogeneity of TLS-CHOP fusion transcript showed no apparent impact on adipogenesis, since both TLS-CHOP type I and II cases could randomly display various levels of lipoblastic differentiation. Furthermore, the 4 cases without definite lipoblasts showed no preference for any specific fusion variants and consisted of one each of TLS-CHOP subtypes. In addition, the fusion transcript variants did not correlate with other ultrastructural features, such as the presence and amount of glycogen, mitochondria, rough endoplasmic reticulum, vimentin-like intermediate filaments, and external lamina. However, there appeared to have a trend suggesting the predilections of glycogen particles and vimentin-like intermediate filaments in primitive mesenchymal cells and/or transitional cells. These findings cannot substantiate the hypothesis that the molecular variability of fusion transcripts has a biological impact on adipogenesis of MLS, and other factors might be implicated in their level of differentiation.

Adipocytes↗

PubMed2004

Remarkable aliphatic hydroxylation by the diiron enzyme toluene 4-monooxygenase in reactions with radical or cation diagnostic probes norcarane, 1,1-dimethylcyclopropane, and 1,1-diethylcyclopropane.

Toluene 4-monooxygenase (T4MO) catalyzes the hydroxylation of toluene to yield 96% p-cresol. This diiron enzyme complex was used to oxidize norcarane (bicyclo[4.1.0]heptane), 1,1-dimethylcyclopropane, and 1,1-diethylcyclopropane, substrate analogues that can undergo diagnostic reactions upon the production of transient radical or cationic intermediates. Norcarane closely matches the shape and volume of the natural substrate toluene. Reaction of isoforms of the hydroxylase component of T4MO (T4moH) with different regiospecificities for toluene hydroxylation (k(cat) approximately 1.9-2.3 s(-)(1) and coupling efficiency approximately 81-96%) revealed similar catalytic parameters for norcarane oxidation (k(cat) approximately 0.3-0.5 s(-)(1) and coupling efficiency approximately 72%). The products included variable amounts of the un-rearranged isomeric norcaranols and cyclohex-2-enyl methanol, a product attributed to rearrangement of a radical oxidation intermediate. A ring-expansion product derived from the norcaranyl C-2 cation, cyclohept-3-enol, was not produced by either the natural enzyme or any of the T4moH isoforms tested. Comparative studies of 1,1-dimethylcyclopropane and 1,1-diethylcyclopropane, diagnostic substrates with differences in size and with approximately 50-fold slower k(cat) values, gave products consistent with both radical rearrangement and cation ring expansion. Examination of the isotopic enrichment of the incorporated O-atoms for all products revealed high-fidelity incorporation of an O-atom from O(2) in the un-rearranged and radical-rearranged products, while the O-atom found in the cation ring-expansion products was predominantly obtained by reaction with H(2)O. The results show a divergence of radical and cation pathways for T4moH-mediated hydroxylation that can be dissected by diagnostic substrate probe rearrangements and by changes in the source of oxygen used for substrate oxygenation.

Cations↗

PubMed1979

Genetic variability within and between outbred Wistar strains of rats.

The allelic frequencies at 6 isozyme loci (Es-1, Es-2, Es-3, Es-4, Es-Si and Amy-1) were examined in 4 outbred Wistar strains and additionally 2 SD strains as controls. From the allelic frequencies, the averages of the heterozygosities in individual strains and the geometric genetic distances between every pair of all possible strain combinations were calculated. The averages of the heterozygosities in 2 SD strains were both intermediate (around 0.2) and the genetic distance between them was rather short. But among the Wistar strains, the averages of the heterozygosities were highly variable and the genetic relationships among them were very variable in their genetic distances. From these results, it was suggested that the outbred Wistar strains were different each other in their genetic constitutions and that no suggestion was obtained to descriminate genetically the Wistar strains from the SD strains.

Alleles↗

PubMed2004

A European survey of antimicrobial susceptibility among zoonotic and commensal bacteria isolated from food-producing animals.

OBJECTIVE: To study antimicrobial resistance in zoonotic bacteria isolated from food animals in different countries using uniform methodology. METHODS: Samples were taken at slaughter from chickens, pigs and cattle in four EU countries per host. Escherichia coli (indicator organism; n = 2118), Salmonella spp. (n = 271) and Campylobacter spp. (n = 1325) were isolated in national laboratories and MICs tested in a central laboratory against, where appropriate, ampicillin, cefepime, cefotaxime, ciprofloxacin, chloramphenicol, erythromycin, gentamicin, nalidixic acid, streptomycin, tetracycline and trimethoprim/sulfamethoxazole. RESULTS: Isolation rates were high for E. coli, low for Salmonella and intermediate for Campylobacter. MIC results showed resistance prevalence varied among compounds, hosts and countries. For E. coli and Salmonella, resistance to newer compounds (cefepime, cefotaxime, ciprofloxacin) was absent or low, but to older compounds (except gentamicin), resistance was variable and higher. E. coli isolates from Sweden showed low resistance, whereas among isolates from Spain (pigs), resistance to ampicillin, chloramphenicol, streptomycin, tetracycline and trimethoprim/sulfamethoxazole was higher; the UK, France, the Netherlands, Germany, Italy and Denmark were intermediate. For Campylobacter spp. isolates from chickens, nalidixic acid and ciprofloxacin resistance was >30% in France and the Netherlands, >6% in the UK and zero in Sweden. Nalidixic acid resistance was high in cattle (20%-64%), whereas ciprofloxacin resistance was markedly lower in cattle, variable in pigs (3%-21%) and highest in Sweden. Generally, Campylobacter coli was more resistant than Campylobacter jejuni. CONCLUSION: Antimicrobial resistance among enteric organisms in food animals varied among countries, particularly for older antimicrobials, but resistance to newer compounds used to treat disease in humans was generally low.

Animals↗

PubMed1971

Discrimination training and stimulus compounding: consideration of non-reinforcement and response differentiation consequences of S.

In Exp. 1, four rats were trained on a two-component multiple schedule with tone and light each associated with different variable-interval schedules. Extinction in light-out no-tone, common to previous studies reporting additive summation to compounded discriminative stimuli, was omitted from training. In testing, the simultaneous presentation of tone and light controlled a response rate intermediate between that controlled by these stimuli presented singly. In Exp. 2, animals were trained on three-ply multiple schedules. While tone and light were each associated with variable-interval schedules for both groups, light-out no-tone signalled extinction for one and differential-reinforcement-of-behavior-other-than-bar-pressing for the other. This permitted response reduction during light-out no-tone to be viewed independently of non-reinforcement. Responding of both groups showed summation to tone plus light in testing, with the effect clearly larger for extinction-trained subjects. These experiments indicate that: (1) discrimination training afforded by extinction has been integral to additive summation previously reported, (2) response differentiation and non-reinforcement consequences of extinction training contribute to the magnitude of summation, and (3) summation and peak shift might be functionally related phenomena.

Journal Article↗

PubMed2000

Prognosis of follicular lymphoma: a predictive model based on a retrospective analysis of 987 cases. Intergruppo Italiano Linfomi.

Patients (n-987) with a histologically confirmed diagnosis of follicular lymphoma were studied with the aim of developing a prognostic model specifically devised for this type of lymphoma. We collected information on age, sex, Ann Arbor stage, number of extranodal disease sites, bone marrow (BM) involvement, bulky disease, B symptom criteria (fever, night sweats, and weight loss), performance status (PS), serum lactate dehydrogenase (LDH) level, serum albumin level, hemoglobin level, and erythrocyte sedimentation rate (ESR). In the training sample of 429 patients with complete data, multivariate analysis showed that age, sex, number of extranodal sites, B symptoms, serum LDH level, and ESR were factors predictive for overall survival. Using these 6 variables, a prognostic model was devised to identify 3 groups at different risk. The 5- and 10-year survival rate was 90% and 65% for patients at low risk, respectively; 75% and 54% for patients at intermediate risk; and 38% and 11% for those at high risk (log-rank test, 86.62; P <. 0001). The model was also predictive (P =.0001) in the validation sample of 265 patients with complete data only for the 6 variables used in the development of the model and even in the group of 210 patients from the validation sample uniformly treated with doxorubicin-containing regimens (P =.0001). The prognostic model appears to be very useful in identifying patients with follicular lymphoma at low, intermediate, or high risk.

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