Epidemiological modeling in a branching population. Particular case of a general SIS model with two age classes

This paper covers the elaboration of a general class of multitype branching processes for modeling in a branching population, the evolution of a disease with horizontal and vertical transmissions. When the size of the population may tend to infinity, normalization must be carried out. As the initial size tends to infinity, the normalized model converges a.s. to a dynamical system the solution of which is the probability law of the state of health for an individual ancestors line. The focal point of this study concerns the transient and asymptotical behaviors of a SIS model with two age classes in a branching population. We will compare the asymptotical probability of extinction on the scale of a finite population and on the scale of an individual in an infinite population: when the rates of transmission are small compared to the rate of renewing the population of susceptibles, the two models lead to a.s. extinction, giving consistent results, which no longer applies to the opposite situation of important transmissions. In that case the size of the population plays a crucial role in the spreading of the disease.

Electrochemical and in vitro evaluation of the redox-properties of kynurenine species

Kynurenines are formed as part of the tryptophan metabolism and are known to exhibit pro- and anti-oxidant activities in vitro. The mapping of these biological redox-systems and identification of potential in vivo targets are therefore of great interest in cellular physiology. Here the redox-behavior of different kynurenines and anthranilic acids is evaluated electrochemically and compared to that of simple model compounds. Electrochemical results are correlated with the activity of these compounds in redox-bioassays where 3-hydroxyanthranilic acid and 3-hydroxykynurenine have significant redox-activity. The specific electrochemical redox-behavior of these two compounds, indicating a particular redox-mechanism involving the hydroxyl group, can be used to rationalize these findings. The results indicate that tryptophan metabolites can undergo a range of complex redox-reactions in vivo whose precise nature critically depends on structural details. As a consequence, some of the kynurenines have the potential to contribute to neuronal damage in brain disorders and stroke.

DMSO-treated HL60 cells: a model of neutrophil-like cells mainly expressing PDE4B subtype

The human promyelocytic HL60 cells acquired a neutrophilic phenotype after a 7- to 10-day DMSO treatment. Fc gammaRII was up-regulated. Fc gammaRI was also up-regulated by an additional IFN-gamma treatment. These cells are able to produce O2*- by NADPH oxidase activation in the presence of immune complexes or phorbol-12-myristate-13-acetate (PMA). A change of their PDE4 subtype profile was also observed: PDE4B was the predominant isoenzyme, PDE4D was down-regulated and PDE4A was no longer detectable. Additionally, the more NADPH oxidase was activated by PMA, the less PDE4A was expressed, suggesting that NADPH oxidase activity could be used as a surrogate marker of PDE4A down-regulation. Rolipram and Ariflo (cilomilast), two selective PDE4 inhibitors, dose-dependently inhibited receptor-coupled activation of superoxide. These results suggest that PDE4B is the main subtype involved in regulating superoxide induced by Fc gammaRs activation. Furthermore, these cells, expressing almost exclusively PDE4B subtype, could be useful to identify selective PDE4B inhibitors.

Training status (endurance or sprint) and catecholamine response to the Wingate-test in women

The aim of this study was to verify if, as for men, training status induces different catecholamine responses to exercise. To do this, we investigated the effect of training status (sprint or endurance) on plasma catecholamine response to a supramaximal exercise in women. Nineteen subjects took part in our study: six untrained subjects (UT), seven endurance trained subjects (ET) and six sprint trained ones (ST). The trained subjects (ET and ST) were all competing at a high national level. The maximal power (W max ) and the mean power (W) were determined from the Wingate-test. Blood lactate, adrenaline (A) and noradrenaline (NA) were analysed at rest (La 0, A 0 and NA 0 ), immediately at the end of the exercise (A max and NA max ) and after 5 min recovery (La max [3 min in arterialized blood], A 5 and NA 5 ). The disappearance of A and NA was judged by the ratio (A max -A 5 )/A max and (NA max -NA 5 )/NA 5. The ratio A max /NA max was considered as an index of the adrenal medulla responsiveness to the sympathetic nervous activity. As expected, during the Wingate-test ST exhibited significantly higher performances compared to UT and ET. But in contrast to the men's data no difference was observed between the three groups both for La max (13.1 +/- 0.8 mmol x L (-1); 14.8 +/- 1.0 mmol x L (-1) and 11.2 +/- 0.5 mmol x L (-1) respectively for ET, ST and UT), NA max (22.1 +/- 1.2 nmol x L (-1); 13.1 +/- 2.4 nmol x L (-1) and 20.2 +/- 7 nmol x L (-1)respectively for ET, ST and UT) and A max (4.1 +/- 0.8 nmol x L (-1); 2.6 +/- 0.6 nmol x L (-1); 13.1 +/- 0.6 nmol x L (-1) respectively for ET, ST and UT). Consequently the ratio A max /NA max was similar in UT, ET and ST (respectively 0.2 +/- 0.03; 0.2 +/- 0.04; 0.17 +/- 0.04), These results indicated, in contrast to the men's data, that the catecholamine response to the Wingate-test did not differ between female subjects of different status of training. In conclusion this study did not find any significant effect of training status on the catecholamine response to supramaximal exercise and so argues in favour of sex differences in response to training.

Type 4 phosphodiesterase-dependent pathways: role in inflammatory processes

Type 4 phosphodiesterases (PDE4) belong to a superfamily of at least 11 isozymes catalyzing the hydrolysis of cyclic AMP (cAMP) and/or cyclic GMP (cGMP). PDE4 regulate intracellular levels of cAMP and are the predominant PDE expressed in inflammatory cells. Elevation of cAMP produces the inhibition of different inflammatory processes, such as cellular trafficking, cytokine release or reactive oxygen species production. But recent papers showed that the involvement of PDE4 in inflammatory mechanisms cannot be completely attributed to a cAMP-dependent pathway. The wide range of inflammatory mechanisms controlled by PDE4 designated these enzymes as a good target for anti-inflammatory compounds. PDE4 inhibitors have been demonstrated to be very potent in the treatment of chronic inflammatory diseases like asthma or chronic obstructive pulmonary disease (COPD) but their therapeutic window has yet to be improved.

Oxidation of biological thiols by highly reactive disulfide-S-oxides

Oxidative stress involves the generation of a number of reactive species, among them 'reactive oxygen species' and 'reactive nitrogen species'. Recent reports have indicated that disulfide-S-monoxides (thiosulfinates) and disulfide-S-dioxides (thiosulfonates) are formed under conditions of oxidative stress. We have now been able to demonstrate that these species are highly reactive and rapidly oxidise thiols. Glutathione and cysteine were oxidised to mixed disulfides by the action of disulfide-S-oxides. Oxidative attack on the zinc/sulfur protein metallothionein with concomitant zinc release was readily accomplished by these 'reactive sulfur species' whereas hydrogen peroxide showed minimal zinc release.

Genetic contributions of nonautoimmune SWR mice toward lupus nephritis

(SWR x New Zealand Black (NZB))F(1) (or SNF(1)) mice succumb to lupus nephritis. Although several NZB lupus susceptibility loci have been identified in other crosses, the potential genetic contributions of SWR to lupus remain unknown. To ascertain this, a panel of 86 NZB x F(1) backcross mice was immunophenotyped and genome scanned. Linkage analysis revealed four dominant SWR susceptibility loci (H2, Swrl-1, Swrl-2, and Swrl-3) and a recessive NZB locus, Nba1. Early mortality was most strongly linked to the H2 locus on chromosome (Chr) 17 (log likelihood of the odds (LOD) = 4.59 - 5.38). Susceptibility to glomerulonephritis was linked to H2 (Chr 17, LOD = 2.37 - 2.70), Swrl-2 (Chr 14, 36 cM, LOD = 2.48 - 2.71), and Nba1 (Chr 4, 75 cM, LOD = 2.15 - 2.23). IgG antinuclear autoantibody development was linked to H2 (Chr 17, LOD = 4.92 - 5.48), Swrl-1 (Chr 1, 86 cM, colocalizing with Sle1 and Nba2, LOD = 2.89 - 2.91), and Swrl-3 (Chr 18, 14 cM, LOD = 2.07 - 2.13). For each phenotype, epistatic interaction of two to three susceptibility loci was required to attain the high penetrance levels seen in the SNF(1) strain. Although the SWR contributions H2, Swrl-1, and Swrl-2 map to loci previously mapped in other strains, often linked to very similar phenotypes, Swrl-3 appears to be a novel locus. In conclusion, lupus in the SNF(1) strain is truly polygenic, with at least four dominant contributions from the SWR strain. The immunological functions and molecular identities of these loci await elucidation.

Electrochemistry of chalcogen compounds: prediction of antioxidant activity

Synthesis and characterisation of organochalcogens has demonstrated a high correlation between their electrochemical oxidation potential on the glassy carbon electrode, their activity in bioassays and an unprecedented antioxidant activity in neuronal cell culture (EC50 approximately 20 nM) making electrochemical methodology a valuable tool in drug design for Alzheimer's and related diseases.

Fund-raising on the web: the effect of an electronic foot-in-the-door on donation

In an attempt to test the foot-in-the-door (FITD) technique in a computer-mediated communication context, 1,008 men and women taken at random in various e-mails lists were solicited to visit a web site for the profit of a humanitarian organization. In the FITD condition, subjects were first solicited to sign a petition form and, after that, they were solicited for a donation. In the control condition, the donation solicitation was formulated directly. In all cases, the formulation of the requests was manipulated by the order of the successive HTML pages of the site. Results show that the FITD procedure increases compliance to the final request.

Hypothesis: the role of reactive sulfur species in oxidative stress

Oxidative stress arises from an imbalance in the metabolism of redox-active species promoting the formation of oxidizing agents. At present, these species are thought to include reactive oxygen, reactive nitrogen, and reactive nitrogen oxygen species (ROS, RNS, and RNOS, respectively). Reactive species have their origin in enzymatic synthesis, environmental induction, or by the further chemical reaction of an active species with other endogenous molecules to generate a second-generation reactive species. These second-generation species possess a different spectrum of activity to the parent species, with different redox reactions and biological targets. We now propose that an additional group of redox active molecules termed "reactive sulfur species" (RSS) are formed in vivo under conditions of oxidative stress. RSS are likely to include disulfide-S-oxides, sulfenic acids, and thiyl radicals, and are predicted to modulate the redox status of biological thiols and disulfides.

Evaluation of a silicone occlusive dressing after laser skin resurfacing

BACKGROUND

Closed dressings are thought to promote postoperative wound healing after laser skin resurfacing; however, quantitative data are lacking.

OBJECTIVE

To compare postoperative healing after combination carbon dioxide and erbium:YAG full-face laser skin resurfacing in patients who were treated with a silicone occlusive dressing (Silon-TSR; Bio Med Sciences, Inc, Bethlehem, Pa) vs open-wound care consisting of soaks and ointment application.

DESIGN

Thirty-five patients with closed dressings compared retrospectively with 35 control subjects with open-wound care. In a prospective evaluation, 27 patients with closed dressings were then compared with 27 historical controls matched by age, sex, skin type, and treatment technique. Erythema, crusting, swelling, pain, pruritus, purpura, long-term complications, and dressing comfort were evaluated.

SETTING

Referral-based academic practice.

RESULTS

Prospectively, closed-dressing and open-wound care groups differed significantly in maximum erythema severity (1.8 vs 2.0 on a scale of 0-3; P =.03), noticeable erythema duration (15.4 vs 31.1 days; P =.04), and time until complete erythema resolution (41.8 vs 96.1 days; P =.02). Swelling resolution was more rapid in the dressing group (12.1 vs 29.5 days; P =.02). Crusting was limited to uncovered areas in the dressing group, and crusting duration was shorter (5.0 vs 9.1 days; P<.001). Pain was more likely to be reported prospectively, but severity was mild, in the closed-dressing group. Other short- and long-term complications did not differ significantly. Subjective patient attitudes toward the dressing were positive.

CONCLUSIONS

Occlusive silicone dressing application decreases immediate postoperative morbidity with significantly reduced severity and duration of erythema and decreased duration of swelling and crusting. Long-term results and complication rates remain unchanged.

Molecular characterization of two ammonium transporters from the ectomycorrhizal fungus Hebeloma cylindrosporum

Heterologous expression of the yeast triple Mep mutant has enabled the first molecular characterization of AMT/MEP family members in an ectomycorrhizal fungus. External hyphae, which play a key role in nitrogen nutrition of trees, are considered as the absorbing structure of the ectomycorrhizal symbiosis and therefore molecular studies on ammonium transport in hyphae are urgently needed. The kinetic properties of AMT2 and AMT3 from Hebeloma cylindrosporum were studied in Saccharomyces cerevisiae. Expression of HcAmts in the yeast triple Mep mutant restored ammonium retention within cells. The HcAmts did not complement the ammonium sensing defect phenotype of Mep2Delta cells during pseudohyphal differentiation. Northern blot analysis in H. cylindrosporum showed that the HcAMTs were up-regulated upon nitrogen deprivation and down-regulated by ammonium.

Effect of training status on the sympathoadrenal activity during a supramaximal exercise in human

BACKGROUND

The study investigated the concentrations of plasma catecholamine, adrenaline (A) and noradrenaline (NA), and the adrenal medulla responsiveness to the sympathetic nervous activity in sprinters (S), endurance runners (E) and untrained subjects (U) during a supramaximal exercise (the Wingate-test).

METHODS

A group of 19 men took part in the tests: 6 S (20.5+/-0.7 years), 6 E (21.0+/-1.0 years) and 7 U (20.9+/-0.4 years). The maximal power (Wmax) and the mean power (W) were determined from the Wingate-test on a cycle ergometer. The plasma lactate, A and NA were analysed at rest (La0, A0 and NA0), immediately at the end of the exercise (Amax and NA(max)) and after 5 min recovery (La(max), A5 and NA5). The disappearance of A and NA was judged by the difference between the maximal values and those determined after 5 min recovery (Amax-A5 and NA(max)-NA5) and the ratio A/NA was considered as an index of the adrenal medulla responsiveness to the sympathetic nervous activity.

RESULTS

During the Wingate-test S exhibited higher performances and higher La(max) than the two other groups. At the end of the Wingate-test the NA(max) values were similar in the three groups whereas the Amax values were significantly higher in S than in E and U (8.00+/-0.5 nmol x l(-1) in S vs 3.47+/-0.30 nmol x l(-1) and 3.29+/-1.14 nmol x l(-1) respectively in E and U). This leads to a higher Amax/NA(max) ratio for S compared to the other two groups (0.77+/-0.10 in S vs 0.23+/-0.03 and 0.28+/-0.05, respectively in E and U). As the disappearance of A (Amax-A5) was significantly higher in S (6.80+/-0.47 nmol x l(-1) in S vs 2.64+/-0.19 nmol x l(-1) and 1.64+/-1.37 nmol x l(-1), respectively in E and U), the higher values of Amax in S could be explained by an increase of the adrenal medullary secretory capacity in this group.

CONCLUSIONS

It was concluded that essentially short term and intense exercises as sprint ones or interval-training may alter the adrenal medulla responsiveness to supramaximal exercise but not long duration exercises.

Molecular cloning, characterization and regulation by cadmium of a superoxide dismutase from the ectomycorrhizal fungus Paxillus involutus

The gene encoding a superoxide dismutase (PiSOD) was cloned by suppressive subtractive hybridization from cDNA library of the ectomycorrhizal fungus, Paxillus involutus, grown under cadmium-stress conditions. The encoded protein was presumed to be localized in the peroxisomes because it contained a C-terminal peroxisomal localization peptide (SKL) and lacked an N-terminal mitochondrial transit peptide. Complementation of an Escherichia coli SOD null strain that is unable to grow in the presence of paraquat or cadmium indicated that cloned Pisod encoded a functional superoxide dismutase. Sensitivity of PiSOD activity to H2O2 but not KCN, and sequence homologies to other SODs strongly suggest that it is a manganese-containing superoxide dismutase. Monitoring PiSOD transcript, immunoreactive polypeptide and superoxide dismutase activity following cadmium stress suggests that the principal level of control is post-translational. This is, to our knowledge, the first insight in the characterization of molecular events that take place in an ectomycorrhizal fungus during exposure to heavy metals.

Relation between carbon ion ranges and x-ray CT numbers

Measurements of carbon ion ranges in various phantom materials and real bones are presented. Together with measured Hounsfield values, an empirical relation between ranges and Hounsfield units is derived, which is an important prerequisite for treatment planning in carbon ion therapy.

[Abuse of flunitrazepam in opioid addicts]

Fifty-three heroin addicts, nineteen of them methadone treated, were asked about their use of flunitrazepam. Drug abuse began after a medical prescription in 50% of cases; flunitrazepam was taken per os, but also i.v. in 19% of cases. The mean daily dose was about 20 mg/day, often associated with other psychotropic drugs, alcohol, opiates or cocaine. Attention is focused on the amnesia and increased feeling of power (11% of cases), often resulting in serious violent offenses.

Assay of a seric human hexapeptide (HWESAS) using a monoclonal antibody and ELISA

Human serum contains low-molecular-weight growth factors potentiating some in vitro biological effects of IGF-I and IGF-II and recently two peptides were mainly identified: HWESAS and WGHE. In order to determine seric HWESAS concentration, a specific monoclonal antibody against HWESAS was prepared. Its specificity was studied by inhibition tests: this antibody cross-reacts with Y-HWESAS, Cys-HWESAS. It does not react with HWESAS when its COOH is blocked, or with HWE, WGHE and tryptophan or with C3f (SSKITHRIHWESASLLR) which is a fragment of human complement containing HWESAS motif. Its affinity was measured by non competitive enzyme immunoassay (3.89+/-2.44.10(8) M(-1)). Then, this antibody was used in enzyme-linked immunosorbent assay (ELISA) and the preliminary assays were performed to detect HWESAS in serum. In contrast to healthy subjects, patients with chronic renal failure exhibited undetectable concentration of hexapeptide while after successful renal transplantation values increased to reach levels found in healthy subjects and varying according to post-operative evolution. These data are a strong hint that the kidney plays an important role in the production of this hexapeptide and underly the clinical interest of HWESAS detection in renal pathology.

[{Pt]

Prolonged evacuation of [{Pt(CO)(3)}(2)](2+) (1), the first homoleptic, dinuclear, cationic platinum(I) carbonyl complex, results in reversible disproportionation. Complex 1 was formed by dissolution of PtO(2) in concentrated H(2)SO(4) under an atmosphere of CO [Eq. (a)], and completely characterized by NMR ((13)C, (195)Pt), IR, and Raman spectroscopy.

Water-soluble organotellurium compounds: catalytic protection against peroxynitrite and release of zinc from metallothionein

The antioxidant properties of a number of water-soluble diorganyl tellurides have been investigated. These organotellurium compounds efficiently protect against peroxynitrite-mediated oxidation of dihydrorhodamine 123, hydroxylation of benzoate, and nitration of 4-hydroxyphenyl acetate. The peroxidation of the zinc storage protein, metallothionein, by tert-butyl hydroperoxide is also catalyzed by the water-soluble organotellurium compounds. As compared to selenium-containing compounds (e.g., ebselen and selenocystamine), some of the tellurides that were tested ¿e.g., 3-[4-(N,N-dimethylamino)benzenetellurenyl]propanesulfonic acid, sodium salt¿ exhibit a significantly higher reactivity in these assays, making them some of the most effective compounds tested thus far. The catalysis of destruction of zinc-sulfur clusters by water-soluble organotellurium compounds could have implications for the bioavailability of zinc in vivo. These compounds might be lead compounds for the development of a new class of water-soluble, tellurium-based antioxidant and zinc-releasing drugs.