Effects of air pollution and climatic conditions on the frequency of ophthalmological emergency examinations.
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Air Pollutants↗
Biomedical subjects
F Thomas
Publications and source records attributed to F Thomas.
Bacterial keratitis: predisposing factors, clinical and microbiological review of 300 cases.
AIM: To identify predisposing factors and to define clinical and microbiological characteristics of bacterial keratitis in current practice. METHODS: A retrospective analysis of the hospital records of patients presenting with bacterial keratitis and treated at the Quinze-Vingts National Center of Ophthalmology, Paris, France, was performed during a 20 month period. A bacterial keratitis was defined as a suppurative corneal infiltrate and overlying epithelial defect associated with presence of bacteria on corneal scraping and/or that was cured with antibiotic therapy. Risk factors, clinical and microbiological data were collected. RESULTS: 300 cases (291 patients) of presumed bacterial keratitis were included. Potential predisposing factors, usually multiple, were identified in 90.6% of cases. Contact lens wear was the main risk factor (50.3%). Trauma or a history of keratopathy was found in 15% and 21% of cases, respectively. An organism was identified in 201 eyes (68%). 83% of the infections involved Gram positive bacteria, 17% involved Gram negative bacteria, and 2% were polymicrobial. Gram negative bacteria were associated with severe anterior chamber inflammation (p=0.004), as well as greater surface of infiltrates (p=0.01). 99% of ulcers resolved with treatment, but only 60% of patients had visual acuity better than the level at admission, and 5% had very poor visual outcome. CONCLUSIONS: Contact lens wear is the most important risk factor. Most community acquired bacterial ulcers resolve with appropriate treatment.
Adolescent↗
Field evidence for density-dependent effects in the trematode Microphallus papillorobustus in its manipulated host, Gammarus insensibilis.
Numerous studies have demonstrated that parasites with complex life cycles frequently manipulate the phenotype of their hosts to increase their transmission rate. Little is known, however, concerning density-dependent processes within infrapopulations of manipulative parasites--whether parasites cooperate to manipulate the host, whether competition counteracts with these potential cooperative benefits, or both. Here we explored these ideas, focusing on the association between the manipulative trematode Microphallus papillorobustus and its second intermediate host, the gammarid Gammarus insensibilis. From the data collected in the field, we found no evidence that co-occurring M. papillorobustus individuals benefit from the presence of conspecifics; instead, individuals in larger infrapopulations suffered reduced size and fecundity. Thus, the net effect of increasing density suggests that competition rather than cooperation is the dominant force in infrapopulations of M. papillorobustus.
Amphipoda↗
Egg size variability in trematodes: test of the bet-hedging hypothesis.
The hypothesis according to which egg size variability in hermaphroditic parasites results from bet-hedging was investigated in a comparative analysis using trematodes as a model. We hypothesized that the species reproducing mainly by self-fertilization should produce smaller eggs than those species that regularly practice cross-fertilization. Indeed, because self-fertilization is usually associated with inbreeding depression, selection should favor individuals spreading the risk of genetically disturbed development across more but smaller eggs, instead of producing fewer eggs, each possessing a large resource supply, of which many may fail to develop because of genetic deficiencies. On the basis of earlier theoretical and empirical studies, we assumed that the ratio length of testis-length of ovary positively correlates with the mating group size and, hence, with opportunities for cross-fertilization. In accordance with the bet-hedging hypothesis, we found, across trematode species, a positive relationship between this ratio and the mean egg volume produced by adults. This result was, however, observed only for the trematodes infecting birds and not for the species infecting fishes and mammals. In addition, once the influence of trematode phylogeny was taken into account, there was no significant trend, suggesting that phylogenetic legacies played a large role in generating the previous signal. Experimental tests of the bet-hedging hypothesis will be necessary to clarify the matter.
Animals↗
[Pulmonary embolism with overflow pulmonary edema].
We report the case of a patient with a febrile acute respiratory failure associated with alveolar opacities localized in the left upper lobe on chest-X-ray. Diagnosis was related to pulmonary embolism with overflow pulmonary edema. Complete recovery was obtained after mechanical ventilation, anticoagulation and a short course of intra venous dobutamine.
Aged↗
Dicopper(II) complexes of H-BPMP-type ligands: pH-induced changes of redox, spectroscopic ((19)F NMR studies of fluorinated complexes), structural properties, and catecholase activities.
Substitution of the methyl group from the H-BPMP (HL(CH)3) ligand (2,6-bis[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenol) by electron withdrawing (F or CF(3)) or electron donating (OCH(3)) groups afforded a series of dinucleating ligand (HL(OCH)3, HL(F), HL(CF)3), allowing one to understand the changes in the properties of the corresponding dicopper complexes. Dinuclear Cu(II) complexes have been synthesized and characterized by spectroscopic (UV-vis, EPR, (1)H NMR) as well as electrochemical techniques and, in some cases, by single-crystal X-ray diffraction: [Cu(2)(L(OCH)3)(muOH)][(ClO(4))(2)].C(4)H(8)O, [Cu(2)(L(F))(muOH)][(ClO(4))(2)], [Cu(2)(L(F))(H(2)O)(2)][(ClO(4))(3)].C(3)D(6)O, and [Cu(2)(L(CF)3)(H(2)O)(2)][(ClO(4))(3)].4H(2)O. Significant differences are observed for the Cu-Cu distance in the two mu-hydroxo complexes (2.980 A (R = OCH(3)) and 2.967 A (R = F)) compared to the two bis aqua complexes (4.084 A (R = F) and 4.222 A (R = CF(3))). The mu-hydroxo and bis aqua complexes are reversibly interconverted upon acid/base titration. In basic medium, new species are reversibly formed and identified as the bis hydroxo complexes except for the complex from HL(CF)3 which is irreversibly transformed near pH = 10. pH-driven interconversions have been studied by UV-vis, EPR, and (1)H NMR, and the corresponding pK are determinated. In addition, with the fluorinated complexes, the changes in the coordination sphere around the copper centers and in their redox states are evidenced by the fluorine chemical shift changes ((19)F NMR). For all the complexes described here, investigations of the catechol oxidase activities (oxidation of 3,5-di-tert-butylcatechol to the corresponding quinone) are of interest in modeling the catecholase enzyme active site and in understanding aspects of structure/reactivity. These studies show the pH-dependence for the catalytic abilities of the complexes, related with changes in the coordination sphere of the metal centers: only the mu-hydroxo complexes from HL(CH)3, HL(F), and HL(OCH)3 exhibit a catecholase activity. Modification on R-substituent induces a drastic effect on the catecholase activity: the presence of an electron donating group on the ligand increases this activity; the reverse effect is observed with an electron withdrawing group.
Catalysis↗
Combined effects of systolic blood pressure and serum cholesterol on cardiovascular mortality in young (<55 years) men and women.
AIMS: To evaluate the combined effects of the two most frequent modifiable risk factors, systolic blood pressure and serum cholesterol, on cardiovascular and coronary mortality, in a large French population aged 18 to 55 years. METHODS AND RESULTS: We studied 108,879 men (mean age 39.1+/-9.4 years) and 84,931 women (mean age 37.3+/-10.0 years) who had a health check-up at the IPC Center between 1978 and 1988. Mortality data for a mean period of 13 years were analysed. Systolic blood pressure and cholesterol levels were classified according to the cut-points proposed by international guidelines. In men, the prevalence of high cholesterol was more than twice as high in hypertensives as in normotensives; in women, it was more than three times higher. The combination of these two risk factors has additive effects on cardiovascular disease and coronary heart disease risk. In men, a borderline elevation of both systolic blood pressure (130-139 mmHg) and cholesterol (200-239 mg x dl(-1)) leads to a three- to four-fold increase in cardiovascular disease risk. Men with systolic blood pressure >or=160 mmHg represent a small percentage (about 5%) who have a 10-fold increase in cardiovascular disease and coronary heart disease risk, especially when high cholesterol is present. In women of the same age, similar trends were observed, but the results were less significant, probably due to the low cardiovascular disease mortality rates. CONCLUSIONS: In conclusion, in French subjects under 55 years of age, a combination of high systolic blood pressure and high serum cholesterol dramatically increased cardiovascular disease and coronary heart disease risk, especially in men. A more aggressive public health policy is needed to prevent the development of risk factors in younger subjects.
Adult↗
Egg production by metacercariae of Microphallus papillorobustus: a reproductive insurance?
This study aimed to determine whether metacercariae of Microphallus papillorobustus (Trematoda: Microphallidae) produce eggs by self-fertilization when their intermediate host, the gammarid Gammarus insensibilis, dies before being eaten by predatory definitive hosts. Such a mechanism would allow the parasite to reproduce even if transmission fails. The percentage of metacercariae that produced eggs and the mean number of eggs were significantly higher in metacercariae placed in a Ringer's solution compared with those in salt water or metacercariae remaining inside the dead gammarid. The lack of egg production in metacercariae removed from dead gammarids in the field supported the idea that self-fertilization is not, for this parasite, a mechanism of reproductive insurance when establishment in the definitive hosts fails.
Animals↗
Negative influence of Gammarinema gammari (Nematoda) on the fecundity of Microphallus papillorobustus (Trematoda): field and experimental evidence.
The gammarid amphipod Gammarus insensibilis frequently harbors adult individuals of the ectoparasitic nematode Gammarinema gammari as well as metacercariae of the trematode Microphallus papillorobostus. After the demonstration in a previous study of a negative relationship between the abundance of these 2 parasites, the nature of the relationship between these 2 parasites was explored in more detail by studying, in the field and in the laboratory, the influence of nematode abundance on trematode fecundity. In gammarids collected in the field, a negative relationship between metacercarial fecundity and the number of co-occurring nematodes was found. By manipulating the nematode abundance in the laboratory, it was confirmed that G. gammari has a negative effect on egg production in M. papillorobustus.
Animals↗
[Fungal keratitis at the Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts: retrospective study of 19 cases].
PURPOSE: To report the spectrum of fungal keratitis at the Centre Hospitalier National d'Ophtalmologie XV-XX, Paris. METHODS: We reviewed 19 cases of fungal keratitis from January 1993 to January 2001. We evaluated the different risk factors, fungal identification, topical and systemic antifungal therapy, surgical treatment and outcome. RESULTS: Nineteen patients were included, 7 women and 12 men, with visual acuity ranging from 9/10 to no perception of light. The mean age was 56.2 years. Patients were hospitalized for an average stay of 16.3 days and all received a diagnostic and therapeutic scraping and 16 received a local antifungal treatment. The most common risk factors were topical steroid treatment (42.1%), corneal graft (31.6%), trauma or foreign body (31.6%). The mean delay between the first signs and fungal keratitis diagnosis was 14 days. Yeast as Candida parapsilosis and albicans were the most frequently isolated fungi (58%), followed by Aspergillus sp. (21%) and Fusarium sp. (21%). The most commonly used topical treatment was amphotericin B, and itraconazole was used as systemic treatment. Five patients had evisceration, 6 had penetrating keratoplasty and 5 retained leukoma. CONCLUSION: Candida was the most frequently isolated fungi and topical steroid treatment the main risk factor. The prognosis is relatively poor (26% of lost vision) because of a delay in diagnosis and other previous ocular pathology or surgery.
Adolescent↗
Reduced pulmonary function is associated with central arterial stiffness in men.
The association of impaired pulmonary function with cardiovascular morbidity and mortality has been reported in several prospective studies. The nature of this association and the mechanisms underlying it are unknown. Both atherosclerosis and central arterial stiffness might be involved. We recently reported, in a 4-yr longitudinal study, that reduced lung function predicts the development of carotid atherosclerotic plaques. In the present study, we report the associations of aortic stiffness with lung function measurements. One hundred and ninety-four men, aged 30 to 70 yr and free of coronary heart disease, who volunteered for a standard health examination were included. FEV(1) and FVC were used to assess lung function. Aortic stiffness was estimated from the carotid-femoral pulse-wave velocity (PWV), which increases proportionally with an increase in aortic stiffness. PWV was significantly and negatively associated with FEV(1) and FVC (partial correlation coefficients adjusted for age and height: -0.27 [p < 0.001] and -0.24 [p < 0.001], respectively). For every 1 SD increase in PWV (2.5 m/s), FEV(1) decreased by 195.2 +/- 50.1 ml (p < 0.001) in an age- and height-adjusted analysis. The corresponding decrease in FVC was 190.4 +/- 55.0 ml (p < 0.001). Further adjustment for cardiovascular risk factors (weight, smoking habits, hypercholesterolemia, diabetes, and hypertension) did not markedly alter these results. In addition, negative associations of PWV with lung function measurements were observed within each category of cardiovascular risk factors. This study suggests that reduced pulmonary function is independently associated with aortic stiffness in men. The interrelations between pulmonary and vascular alterations should be thoroughly investigated.
Adult↗
New 8-hydroxyquinoline and catecholate iron chelators: influence of their partition coefficient on their biological activity.
Four new hexadendate chelators, three hydroxyquinoline-based, Csox, O-Trensox, Cox750, and one catecholate-based CacCam-which have comparable skeletal structures and pFe, but widely different partition coefficients, (Kpart), 0.01, 0.02, 1 and 3.2 respectively, have been tested for their iron chelating efficacy in vitro by two methods. First, by their ability to remove iron from ferritin in solution or second, to remove iron from iron-loaded hepatocytes in vitro. Our objective was to ascertain the importance of Kpart and pFe, on the biological efficiency of the molecule. Previous studies proposed that an ideal value of Kpart of 1 should give maximum biological activity. Mobilization of iron by Csox and CacCAM from ferritin was similar and furthermore more efficient than desferrioxamine B. In the iron-loaded hepatocyte cultures, the three hydroxyquinoline chelators, although showing diversity in terms of lipophilicity, appeared to be very similar in their capacity to chelate iron. CacCAM, the unique catecholate, was the most efficient of the molecules tested, as well as being the least toxic in the cellular model despite having the lowest value of pFe. In conclusion, the use of the partition coefficient and pFe, as tools for predicting biological activity of iron chelators should be not generalized. Further studies are required in order to understand the influence of the structure on the biological activity of the molecule.
Animals↗
Calcium binding properties of gamma-crystallin: calcium ion binds at the Greek key beta gamma-crystallin fold.
The beta- and gamma-crystallins are closely related lens proteins that are members of the betagamma-crystallin superfamily, which also include many non-lens members. Although beta-crystallin is known to be a calcium-binding protein, this property has not been reported in gamma-crystallin. We have studied the calcium binding properties of gamma-crystallin, and we show that it binds 4 mol eq of calcium with a dissociation constant of 90 microm. It also binds the calcium-mimic spectral probes, terbium and Stains-all. Calcium binding does not significantly influence protein secondary and tertiary structures. We present evidence that the Greek key crystallin fold is the site for calcium ion binding in gamma-crystallin. Peptides corresponding to Greek key motif of gamma-crystallin (42 residues) and their mutants were synthesized and studied for calcium binding. These peptides adopt beta-sheet conformation and form aggregates producing beta-sandwich. Our results with peptides show that, in Greek key motif, the amino acid adjacent to the conserved aromatic corner in the "a" strand and three amino acids of the "d" strand participate in calcium binding. We suggest that the betagamma superfamily represents a novel class of calcium-binding proteins with the Greek key betagamma-crystallin fold as potential calcium-binding sites. These results are of significance in understanding the mechanism of calcium homeostasis in the lens.
Amino Acid Motifs↗
Activation of class III ribonucleotide reductase from E. coli. The electron transfer from the iron-sulfur center to S-adenosylmethionine.
The anaerobic ribonucleotide reductase (ARR) from E. coli is the prototype for enzymes that use the combination of S-adenosylmethionine (AdoMet) and an iron-sulfur center for generating catalytically essential free radicals. ARR is a homodimeric alpha2 protein which acquires a glycyl radical during anaerobic incubation with a [4Fe-4S]-containing activating enzyme (beta) and AdoMet under reducing conditions. Here we show that the EPR-active S = 1/2 reduced [4Fe-4S]+ cluster is competent for AdoMet reductive cleavage, yielding 1 equiv of methionine and almost 1 equiv of glycyl radical. These data support the proposal that the glycyl radical results from a one-electron oxidation of the reduced cluster by AdoMet. Reduced protein beta alone is also able to reduce AdoMet but only in the presence of DTT. However, in that case, 2 equiv of methionine per reduced cluster was formed. This unusual stoichiometry and combined EPR and Mössbauer spectroscopic analysis are used to tentatively propose that AdoMet reductive cleavage proceeds by an alternative mechanism involving catalytically active [3Fe-4S] intermediate clusters.
Anaerobiosis↗
Long-term clinical outcome of human immunodeficiency virus-infected patients with discordant immunologic and virologic responses to a protease inhibitor-containing regimen.
Within a prospective cohort of 150 human immunodeficiency virus (HIV)-infected patients who began first-line protease inhibitor therapy in 1996, the outcome of 42 patients with discrepant virologic and immunologic responses to antiretroviral treatment at 12 months was analyzed at 30 months of treatment. The incidence of AIDS-defining events and deaths (14%) in the group of patients with immunologic responses in the absence of a virologic response was higher than that in full-responder patients (2%); yet, the incidence in this group was lower than that in patients with no immunologic response, despite a virologic response (21%), and was lower than that in patients without an immunologic or virologic response (67%; P<.0001, log-rank test). Differences in outcome were significant (relative risk, 6.9; 95% confidence interval, 1.9-39.3) when factors for progression were compared with those of responder patients. The results support the relevance of the CD4 cell marker over plasma HIV load for predicting clinical outcome in patients who do not achieve full immunologic and virologic responses.
Adult↗
Topoisomerase II inhibitor induced leukemia in a patient with AIDS.
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Acquired Immunodeficiency Syndrome↗
Gender differences in the relation between food cravings and mood in an adult community: Results from the fleurbaix laventie ville santé study.
OBJECTIVE: The aim of this survey was to study food cravings and its indulgence in community adults (538 women and 506 men) and to compare nutritional parameters, weight preoccupations, and weight history between cravers and noncravers. METHOD: Cravers experienced a strong urge to eat specific foods more than once a week during the past 6 months. Food intake was estimated by a 3-day food record. RESULTS: 28% of women and 13% of men were food cravers. Cravers, especially women, were more frequently concerned about their weight than noncravers. Energy intake during snacks was higher in cravers. Less than 40% of cravers reported being hungry when they experienced cravings. Women cravers indulged their cravings as often as men. They reported more frequently negative feelings, whereas men reported more frequently positive feelings. DISCUSSION: This study shows that food craving episodes are strongly associated with mood but in a different way in women and men.
Adult↗
Transfer of organic matter between wastewater and activated sludge flocs.
The organic matter of wastewater was fractionated into settleable (i.e., particulate) and non-settleable (i.e., colloidal + soluble) fractions by settling followed by 0.22 micron filtration. Particulate, colloidal and soluble proportions were found to be relatively constant (45, 31 and 24% of the total COD, respectively). Transfer of soluble fraction always occurred from the wastewater to the activated sludge flocs, whereas bidirectional transfer occurred for the colloidal fraction. The transfer of soluble and colloidal matter reached a steady state after 40 min-mixing and 20 min-mixing, respectively. Desorption of a part of the colloidal organic matter pre-sorbed on the activated sludge flocs was evidenced. The biosorption capacity of activated sludge was around 40-100 mgCODg-1TSS. The biosorbable fraction of wastewater represented on average 45% of the non-settleable fraction.
Colloids↗