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PubMed2004

Adaptive filtering for ECG rejection from surface EMG recordings.

Surface electromyograms (EMG) of back muscles are often corrupted by electrocardiogram (ECG) signals. This noise in the EMG signals does not allow to appreciate correctly the spectral content of the EMG signals and to follow its evolution during, for example, a fatigue process. Several methods have been proposed to reject the ECG noise from EMG recordings, but seldom taking into account the eventual changes in ECG characteristics during the experiment. In this paper we propose an adaptive filtering algorithm specifically developed for the rejection of the electrocardiogram corrupting surface electromyograms (SEMG). The first step of the study was to choose the ECG electrode position in order to record the ECG with a shape similar to that found in the noised SEMGs. Then, the efficiency of different algorithms were tested on 28 erector spinae SEMG recordings. The best algorithm belongs to the fast recursive least square family (FRLS). More precisely, the best results were obtained with the simplified formulation of a FRLS algorithm. As an application of the adaptive filtering, the paper compares the evolutions of spectral parameters of noised or denoised (after adaptive filtering) surface EMGs recorded on erector spinae muscles during a trunk extension. The fatigue test was analyzed on 16 EMG recordings. After adaptive filtering, mean initial values of energy and of mean power frequency (MPF) were significantly lower and higher respectively. The differences corresponded to the removal of the ECG components. Furthermore, classical fatigue criteria (increase in energy and decrease in MPF values over time during the fatigue test) were better observed on the denoised EMGs. The mean values of the slopes of the energy-time and MPF-time linear relationships differed significantly when established before and after adaptive filtering. These results account for the efficacy of the adaptive filtering method proposed here to denoise electrophysiological signals.

Algorithms↗

PubMed1992

[Adverse prognostic influence of diabetes mellitus and hyperglycemia on the clinical course of cerebral infarction].

We accessed the potential impact of diabetes mellitus and hyperglycemia on early prognosis in a study of 109 cases of CT proved brain infarction. Main end-points of this study were 30-days case-fatality rates and the probability of early discharge or prolonged hospitalization. Proportions of patients exhibiting diverse evolutions were compared by Fisher's test and, when the number of observations permitted, by chi-square test. Diabetes mellitus was diagnosed by history in 15.6% (17 patients). In 86 cases analysed within 72 hours of admission, hyperglycemia (glucose level higher than 110 mg/dL) was detected in 67.4% (including all 14 diabetic patients (35.3% vs 21.7%; p = 0.18), but these patients probably were discharged early less frequently (23.5% vs 51.1%; p = 0.06). Compared to the normoglycemic patients, hyperglycemic patients also fared worse, when considering altogether the early discharge and case fatality rates and the need for prolonged hospitalization (p = 0.06). They also exhibited a nonsignificant increase in early case fatality rate (31% vs 15.4%; p = 0.21) and a markedly reduced chance of obtaining early hospital discharge (37.9% vs 65.4%; p = 0.03). Case fatality rates were maximal in diabetic hyperglycemic patients (42.9%) and seemed intermediate in non-diabetic hyperglycemic patients (27.3%). Considering the three end-points evaluated, the apparent differences between non-diabetic hyper and normoglycemic patients did not reach statistical significance (p = 0.19). These results suggest that both diabetes mellitus and hyperglycemia "per se" have deleterious effects on the clinical evolution of patients with cerebral infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1979

[Walker's 256 carcinosarcoma: metastatic dissemination in two cell lines (author's transl)].

Walker's 256 carcinosarcoma a transplantable tumor of the rate changes its behaviour as a consequence of various factors. In this paper we compare the evolution of 2 lines of the tumor: WM 16 (muscular) and Christ Hospital (ascitic) both inoculated intramuscularly. Animals receiving line WM 16 had a severe rapidly progressive evolution dying around day 14 after inoculation with diffuse metastases to lymph nodes (65% of animals), kidneys (53%), spleen (50%), lungs (46.5%), liver (45%), bone marrow (44.8%), in 56% of the animals there were circulating tumoral cells. Animals receiving Christ Hospital line survived up to 40 days, metastases were limited do lungs (48.7%) and lymph nodes (31.7%) and only in 2 of 45 animals circulating tumoral cells were observed.

Animals↗

PubMed2002

Tacrolimus and low-dose steroid immunosuppression preserves bone mass after renal transplantation.

Bone loss, a recognized complication of renal transplantation (TP), is mainly attributed to steroids. The effect of other immunosuppressive agents on patients' bone mass is difficult to distinguish from that of steroids. In this study, we evaluate the evolution of bone mass density over the first 12 months following renal TP in two groups of patients given either low-dose steroids with tacrolimus ( n=7) or normal-dose steroids and cyclosporine ( n=19). Bone mineral density (BMD) of the lumbar spine, total hip, and hip subregions and total-body bone mineral content (BMC) were measured by dual-energy X-ray absorptiometry within the first 15 days, and 1 year after TP. Biological markers of bone turnover (serum calcium, phosphate, total alkaline phosphatase activity, intact parathyroid hormone, bone-specific alkaline phosphatase, calcitriol, and urinary pyridinolines) were regularly measured during follow-up. After TP, renal function improved rapidly in all patients. One year after TP, bone mass had decreased significantly in the cyclosporine group in all investigated sites. By contrast it had increased in the tacrolimus group. In order to compare the evolution of bone mass in patients given similar amounts of steroids, the cyclosporine group was subdivided in tertiles according to the 1-year cumulative oral intake of prednisolone. A significant bone loss was still observed in the low-steroid cyclosporine subgroup but not in the tacrolimus group, despite the similar steroids intake (3.5+/-0.5 g and 2.7+/-1 g, respectively). Bone gain in the tacrolimus group occurred despite a previous longer dialysis duration and a higher number of postmenopausal women who were not receiving hormone substitutes. Long-term evaluation of bone density (3-5 years post-TP) confirmed the bone gain in the tacrolimus patients. Interestingly, the profile of the biological markers of bone turnover appeared better in patients prescribed tacrolimus than in those given cyclosporine, though the differences did not reach statistical significance. Weconclude that tacrolimus associated with low-dose steroids might better preserve bone mass after renal TP than cyclosporine and normal doses of steroids.

Absorptiometry, Photon↗

PubMed1994

Isolation, characterization and expression of cDNAs encoding the catfish-type and chicken-II-type gonadotropin-releasing-hormone precursors in the African catfish.

The cDNAs encoding the catfish prepro-gonadotropin-releasing hormone and the chicken prepro-gonadotropin-releasing hormone II of the African catfish (Clarias gariepinus) have been isolated and sequenced. The catfish gonadotropin-releasing-hormone precursor and the chicken gonadotropin-releasing-hormone-II precursor have the same overall architecture as other gonadotropin-releasing-hormone precursors identified so far; each is composed of a signal peptide, gonadotropin-releasing hormone and a gonadotropin-releasing-hormone-associated peptide which is connected to gonadotropin-releasing hormone and chicken gonadotropin-releasing hormone II, in combination with the Gly-Lys-Arg sequence, are highly conserved during evolution when compared with the corresponding regions of mammalian, avian (chicken gonadotropin-releasing hormone I) and other fish gonadotropin-releasing-hormone precursors. However, the gonadotropin-releasing-hormone-associated peptide regions are markedly divergent. Northern-blot analysis revealed the presence of a single catfish gonadotropin-releasing-hormone mRNA species of about 470 bases, and the presence of a single chicken gonadotropin-releasing-hormone-II mRNA species of about 650 bases in the African catfish brain. In situ hybridization revealed catfish gonadotropin-releasing-hormone cell bodies rostro-caudally scattered in the olfactory nerve, along both sides of the midline of the telencephalon, in the preoptic area of the ventral hypothalamus, and in the infundibular stalk close to the pituitary. Chicken gonadotropin-releasing-hormone-II cell bodies, however, were exclusively found in the midbrain tegmentum.

Amino Acid Sequence↗

PubMed1995

Differential progression of complex and smooth stenoses within the same coronary tree in men with stable coronary artery disease.

OBJECTIVES: We sought to compare the evolution of complex and smooth stenoses within the same coronary tree in patients with stable coronary artery disease. BACKGROUND: Progression of coronary stenosis has prognostic significance and may be influenced by local and systemic factors. Stenosis morphology is a determinant of disease progression, but no previous study has systematically assessed progression of complex and smooth stenoses within the same patient. METHODS: We studied 50 men with stable angina who 1) had one complex coronary stenosis and one smooth stenosis in different noninfarct-related coronary vessels at initial coronary angiography, and 2) had a second angiogram after a median interval of 9 months (range 3 to 24). Patients with lesions > or = 10 mm long, at a major branching point or with > 85% diameter reduction were not included. Coronary lesions were measured quantitatively from comparable end-diastolic frames. Stenosis morphology was determined qualitatively by two independent observers. RESULTS: All patients remained in stable condition during follow-up. Progression, defined as an increase in diameter stenosis by > or = 15% was seen in only eight complex stenosis (16%) but in no smooth lesions (p < 0.01). The severity of complex stenoses changed more than that of corresponding smooth stenoses (mean +/- 1 SD 5.8 +/- 13% vs. -0.06 +/- 6%, p < 0.01). On average, the annual rate of growth was 11.4 +/- 28% and 1.5 +/- 14% for complex and smooth lesions, respectively (p < 0.01). CONCLUSIONS: Few coronary stenoses progress rapidly in stable angina. Complex and smooth coronary stenoses progress at different rates within the same coronary tree. complex stenosis morphology itself is an important determinant of progression of stenosis in patients with apparently clinically stable coronary artery disease.

Aged↗

PubMed2002

Comparative study of the temporal evolution of atmospheric lead deposition in Scotland and eastern Canada using blanket peat bogs.

The temporal evolution of atmospheric lead deposition and its possible sources were assessed in eastern Canada and in western Scotland, using blanket peat bogs as geochemical archives. Short cores were taken from two remote sites located close to the sea. Significant lead enrichments in the upper layers at both sites reflect the increasing emission of lead into the atmosphere due to anthropogenic activities during the last century. At the Scottish site, a region under aeolian influence from Europe, anthropogenic derived lead could be recognized by the distinctive unradiogenic composition (206Pb/207Pb ratios down to approximately 1.115), being clearly different from the pre-industrial values (206Pb/207Pb approximately 1.166). In contrast, the lead pollution in eastern Canada (influenced by North American sources) is identified by a more radiogenic lead isotope composition (206Pb/207Pb ratios up to approximately 1.199) compared to preindustrial values (206Pb/207Pb approximately 1.161). Emission inventories and isotope characteristics suggest that industrial (coal burning, mining) and traffic (leaded gasoline) outputs are the most likely sources during the first and the second half of the 20th century, respectively, in both, western Scotland and eastern Canada alike. The Scottish record is in line with previous studies of past atmospheric lead deposition. However, the Canadian deposit suggests that the wind derived, pre-industrial lead, is less radiogenic as previously implied using sediment archives. These results are thus the first to report pre-industrial lead isotope ratios and concentrations of atmospheric derived aerosols in North America.

Air Pollutants↗

PubMed2004

Autopoiesis with or without cognition: defining life at its edge.

This paper examines two questions related to autopoiesis as a theory for minimal life: (i) the relation between autopoiesis and cognition; and (ii) the question as to whether autopoiesis is the necessary and sufficient condition for life. First, we consider the concept of cognition in the spirit of Maturana and Varela: in contradistinction to the representationalistic point of view, cognition is construed as interaction between and mutual definition of a living unit and its environment. The most direct form of cognition for a cell is thus metabolism itself, which necessarily implies exchange with the environment and therefore a simultaneous coming to being for the organism and for the environment. A second level of cognition is recognized in the adaptation of the living unit to new foreign molecules, by way of a change in its metabolic pattern. We draw here an analogy with the ideas developed by Piaget, who recognizes in cognition the two distinct steps of assimilation and accommodation. While assimilation is the equivalent of uptake and exchange of usual metabolites, accommodation corresponds to biological adaptation, which in turn is the basis for evolution. By comparing a micro-organism with a vesicle that uptakes a precursor for its own self-reproduction, we arrive at the conclusion that (a) the very lowest level of cognition is the condition for life, and (b) the lowest level of cognition does not reduce to the lowest level of autopoiesis. As a consequence, autopoiesis alone is only a necessary, but not sufficient, condition for life. The broader consequences of this analysis of cognition for minimal living systems are considered.

Artificial Intelligence↗

PubMed1987

[Acute myocardial infarction. Different treatment, different prognosis?].

Many statistics demonstrate a definite improvement of myocardial infarction during hospitalization, especially a decrease in the mortality. It appears tempting to credit that improvement to the numerous modifications of the treatment of this dangerous disease in the last few decades. The study reported here indicates, however, that other factors must be taken into account. We compared the evolution of two groups of patients hospitalized for acute myocardial infection, 10 years apart: The first group (G1) of 731 patients corresponds to years 1970-1975; the second group (G2) of 729 patients, corresponds to the years 1984-85-86. During these ten years, mortality decreased by 38 p. cent, from 19.2 p. cent (G1) to 11.9 p. cent (G2). This decrease remains significant regardless of age and sex, except in two subgroups with the least number of patients, i.e. women under the age of 65 and men over 65. It should be noted that rhythm disorders occur with the same frequency in both sub-groups while atrio-ventricular blocks seem to have decreased. The difference in the mortality cannot be attributed to the patient's selection. In fact, in both groups, they are comparable regarding the men/women ratio, the age distribution and the presence of main risk factors (tobacco abuse, dyslipidemia, arterial hypertension, diabetes, heredity). The treatment results in many alterations especially concerning diuretics which seem to be used in approximately 30 p. cent of the patients in both groups. On the contrary, steroids, prescribed in 25.3 p. cent of G1 patients are abandoned; electro-systolic stimulation established in 21.2 p. cent of G1 patients, concerned only 4 p. cent of G2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed2005

Time-resolved infrared absorption studies of the solvent-dependent vibrational relaxation dynamics of chlorine dioxide.

We report a series of time-resolved infrared absorption studies on chlorine dioxide (OClO) dissolved in H2O, D2O, and acetonitrile. Following the photoexcitation at 401 nm, the evolution in optical density for frequencies corresponding to asymmetric stretch of OClO is measured with a time resolution of 120+/-50 fs. The experimentally determined optical-density evolution is compared with theoretical models of OClO vibrational relaxation derived from collisional models as well as classical molecular-dynamics (MD) studies. The vibrational relaxation rates in D2O are reduced by a factor of 3 relative to H2O consistent with the predictions of MD. This difference reflects modification of the frequency-dependent solvent-solute coupling accompanying isotopic substitution of the solvent. Also, the geminate-recombination quantum yield for the primary photofragments resulting in the reformation of ground-state OClO is reduced in D2O relative to H2O. It is proposed that this reduction reflects enhancement of the dissociation rate accompanying vibrational excitation along the asymmetric-stretch coordinate. In contrast to H2O and D2O, the vibrational-relaxation dynamics in acetonitrile are not well described by the theoretical models. Reproduction of the optical-density evolution in acetonitrile requires significant modification of the frequency-dependent solvent-solute coupling derived from MD. It is proposed that this modification reflects vibrational-energy transfer from the asymmetric stretch of OClO to the methyl rock of acetonitrile. In total, the results presented here provide a detailed description of the solvent-dependent geminate-recombination and vibrational-relaxation dynamics of OClO in solution.

Journal Article↗

PubMed1990

Large sequence divergence among mitochondrial DNA genotypes within populations of eastern African black-backed jackals.

In discussions about the relative rate of molecular evolution, intraspecific variability in rate is rarely considered. An underlying assumption is that intraspecific sequence differences are small, and thus variations in rate would be difficult to detect or would not affect comparisons among distantly related taxa. However, several studies on mammalian mitochondrial DNA (mtDNA) have revealed considerable intraspecific sequence divergence. In this report, we test for differences in the rate of intraspecific evolution by comparing mtDNA sequences, as inferred from restriction site polymorphisms and direct sequencing, between mtDNA genotypes of the eastern African black-backed jackal, Canis mesomelas elongae, and those of two other sympatric jackal species. Our results are unusual for several reasons. First, mtDNA sequence divergence within several contiguous black-backed jackal populations is large (8.0%). Previous intraspecific studies of terrestrial mammals have generally found values of less than 5% within a single population, with larger divergence values most often occurring among mtDNA genotypes from geographically distant or isolated localities. Second, only 4 mtDNA genotypes were present in our sample of 64 jackals. The large sequence divergence observed among these mtDNA genotypes suggests there should be many more genotypes of intermediate sequence divergence if they had evolved in sympatry. Finally, estimates of the rate of mtDNA sequence evolution differ by approximately 2- to 4-fold among black-backed jackal mtDNA genotypes, thus indicating a substantial heterogeneity in the rate of sequence evolution. The results are difficult to reconcile with ideas of a constant molecular clock based on random fixation of selectively neutral or nearly neutral mtDNA sequence mutations.

Africa, Eastern↗

PubMed2001

Origin of H1 linker histones.

In which taxa did H1 linker histones appear in the course of evolution? Detailed comparative analysis of the histone H1 and histone H1-related sequences available to date suggests that the origin of histone H1 can be traced to bacteria. The data also reveal that the sequence corresponding to the 'winged helix' motif of the globular structural domain, a domain characteristic of all metazoan histone H1 molecules, is evolutionarily conserved and appears separately in several divergent lines of protists. Some protists, however, appear to have only a lysine-rich basic protein, which has compositional similarity to some of the histone H1-like proteins from eubacteria and to the carboxy-terminal domain of the H1 linker histones from animals and plants. No lysine-rich basic proteins have been described in archaebacteria. The data presented in this review provide the surprising conclusion that whereas DNA-condensing H1-related histones may have arisen early in evolution in eubacteria, the appearance of the sequence motif corresponding to the globular domain of metazoan H1s occurred much later in the protists, after and independently of the appearance of the chromosomal core histones in archaebacteria.

Amino Acid Sequence↗

PubMed1989

Course of psychosis in Algeria and in France: about 342 cases observed from 1975 to 1985.

The aim of this study was to compare the evolution of psychotic patients in Algeria and in France. In 1975, 105 patients were selected in Algeria and 237 in France. Ten years later, in 1985, all these patients were interviewed. In 1985, we investigated for each subject the evolution of the following parameters: sex, age, DSM-III axis 1 and 5, marital status, social welfare work, and treatment variables. Our results indicate that the improvement of the psychosocial adaptation (DSM-III axis 5) is slightly better in Algeria than in France. Medical and social support seems to be quantitatively less important in Algeria.

Adult↗

PubMed1997

[Advanced maternal age and pregnancy: how much is too much?].

Perinatal evolution was compared and two study groups in women with advanced maternal age and pregnancy. 626 were included from a total of 778 with age 35 years, who resolved their pregnancy during 1995. They were classified, according to age, in two groups: 1) maternal age of 35-39 year; they were considered primigestas and multigestas. Perinatal complications were classified in personal antecedent, antepartum and intrapartum complications. To analyze the association between maternal age and parity with perinatal complications, X2 or exact test of Fisher, was used. Percentage of women with advanced age and pregnancy was 13.6%. Main perinatal complications were: preeclapmsia, gestational diabetes, preterm delivery threat, and membranes rupture. There were no significant differences as to complications by age and parity. There were 90% of children with 2500 g, and Apgar of 97%. Perinatal death was 0.4%, and fetal malformation 0.6%. Cesarean frequency, was over 90% in primigestas and in more of 60% in multigestas. Perinatal evolution in advanced age and pregnancy is adequate, if she starts prenatal control early enough.

Adult↗

PubMedDate not supplied

[The usefulness of the timeliness of endoscopic sphincterotomy in severe acute pancreatitis of biliary origin].

There are evidence indicating that endoscopic retrograde cholangiopancreatography with sphincterotomy (ERCP+S) reduces the rate of complications in patients with severe acute biliary pancreatitis (ABP). The aim of this study was to analyze our experience in the treatment of severe ABP with ERCP+S and compare the evolution of the patients treated early (3 days or less following admission) with those treated late (after the 3rd day). A retrospective review of the clinical histories of the 16 patients with severe ABP treated with ERCP+S over the last two years is presented, analyzing their clinical features on admission and evolution. Biliary stones or biliary sludge was observed in 11 cases (69%). Nine patients had undergone early, and 7 late, ERCP+S. The patients of the latter group presented a greater number of complications during evolution than the former group (43% vs 0%; p = 0.025). The mortality of the patients of the late ERCP+S was also greater although without statistical significance (28.6% vs 0%; p = 0.15). No complication secondary to ERCP+S was detected. These findings confirm the fact that ERCP+S performed early in severe ABP significantly reduces the number of complications and is associated with a lower mortality.

Acute Disease↗

PubMed1983

The influence of gut function on lymphoid cell populations in the intestinal mucosa of lambs.

The number and type of lymphoid cells in the intestinal mucosa of lambs change during the first weeks after birth. The influence of gut function on these changes was examined by comparing the evolution of lymphoid cell populations in normal ileum with that in lengths of ileum which had been isolated surgically from the functional intestinal tract of the lamb before birth. The isolated lengths of ileum had a normal blood and nerve supply and they remained healthy throughout a period of at least 2 years, although they did not have a normal histological development. In comparison with normal ileum, the villi of the isolated ileal segments were much smaller and there were many fewer intraepithelial lymphocytes; the lamina propria had significantly fewer lymphocytes than the functional ileum and only a few plasma cells. When isolated ileal segments were reconnected into the intestinal tract after having been isolated from it for 1-3 months, the histology of the mucosa reverted to that of the normal gut, with the same number and types of lymphoid cells. Radiolabelled lymphoblasts collected from intestinal lymph and injected intravenously accumulated to only a small extent in isolated segments of ileum compared with either the normal or the reconnected segments of ileum. This suggested that the paucity of lymphocytes in the mucosa of the isolated segments was due to a reduced extravasation of these cells there. The influence which the gut contents exert on the lymphoid cell population in the mucosa is probably associated with antigenic stimulation but may also be related to other factors concerned in the normal digestive functions of the gut.

Animals↗

PubMed1996

Photoinhibition of photosystem II from higher plants. Effect of copper inhibition.

Strong illumination of Cu(II)-inhibited photosystem II membranes resulted in a faster loss of oxygen evolution activity compared with that of the intact samples. The phenomenon was oxygen- and temperature-dependent. However, D1 protein degradation rate was similar in both preparations and slower than that found in non-oxygen evolving PSII particles (i.e. Mn-depleted photosystem II). These results seem to indicate that during illumination Cu(II)-inhibited samples do not behave as a typical non-oxygen evolving photosystem II. Cytochrome b559 was functional in the presence of Cu(II). The effect of Cu(II) inhibition decreased the amount of photoreduced cytochrome b559 and slowed down the rate of its photoreduction. The presence of Cu(II) during illumination seems to protect P680 against photodamage as occurs in photosystem II reaction centers when the acceptor side is protected. The data were consistent with the finding that production of singlet oxygen was highly reduced in the preparations treated with Cu(II). EPR spin trapping experiments showed that inactivation of Cu(II)-treated samples was dominated by hydroxyl radical, and the loss of oxygen evolution activity was diminished by the presence of superoxide dismutase and catalase. These results indicate that the rapid loss of oxygen evolution activity in the presence of Cu(II) is mainly due to the formation of .OH radicals from superoxide ion via a Cu(II)-catalyzed Haber-Weiss mechanism. Considering that this inactivation process was oxygen-dependent, we propose that the formation of superoxide occurs in the acceptor side of photosystem II by interaction of molecular oxygen with reduced electron acceptor species, and thus, the primarily Cu(II)-inhibitory site in photosystem II is on the acceptor side.

Catalase↗

PubMed1975

[Research in sociotherapy].

The author compares his experience in two psychiatric institutions: an old one of the traditional type, a new one of the psychotherpeutic type. He tries and defines the role of the different members of the staff and compares the evolution of the traditional institute and of the more recent clinic. In the psychotherapeutic institution, there is a drift of the therapeutic role from the physician to the nurse, and finally from the nurse to the patient himself. Despite the fact that they are open, the therapeutic groups become more efficient with time in relation to the maturation of the nursing personal. This slow growth of the psychotherapeutic role of the institutional group finally depends as much on the inhibitions of the nursing staff than on the anxiety of the patients.

Hospitalization↗