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Results for “Comparative evolution”

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At least 163 records · Page 9Linked to original sources

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↗

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↗

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↗

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↗

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↗

PubMed1986

Comparative kinetics study of the evolution of freshwater aquatic toxicity and biodegradability of linear and branched alkylbenzene sulfonates.

Evolution of both primary biodegradability and acute toxicity to daphnia and zebra fish of a linear alkylbenzene sodium sulfonate (LAS) and a branched alkylbenzene sodium sulfonate (BAS) have been measured simultaneously. In six of eight experiments, LAS was biodegraded to 90% in 7 days and BAS to 70% in 7 days. In the two other experiments, both LAS and BAS have shown the same biodegradation speed and reached the same biodegradation level in 7 days: 45% in one experiment and 55% in the other. The composition of bacteria population and the level of cellular ATP of the inoculum play a decisive role in the biodegradation. These results confirm that it is essential to know the composition of bacteria population present in the inoculum as well as their biochemical characteristics to accurately interpret results of biodegradation tests. In the case of a rapid primary biodegradation of LAS and BAS, the acute toxicity of LAS remains three times as high as that of BAS for at least 24 hr toward daphnia and 48 hr toward zebra fish. Their acute toxicity to daphnia and zebra fish become equivalent only after 72 hr. When primary biodegradation of both products is slower, the acute toxicity of LAS remains higher than that of BAS for more than 7 days.

Alkanesulfonates↗

PubMed1978

Parvalbumins from coelacanth muscle. II. Amino acid sequence of the two less acidic components.

The primary structure of the two less acidic parvalbumins (pI = 5.44 and pI = 4.95) from coelacanth muscle (Latimeria chalumnae) has been determined. They differ only by the presence or absence of a N-terminal blocking group. By the use of the automatic degradation, 69 amino acids could be placed unambiguously in the N-terminal part and 24 amino acids following the single arginine 75. Tryptic peptides were used to establish the sequence and the position of the remaining residues. The two parvalbumins examined belong to the alpha-lineage, and the rate of their molecular evolution is comparable to that found in other vertebrates.

Amino Acid Sequence↗

PubMed1991

Effects of CDP-choline on the recovery of patients with head injury.

A single blind randomized study has been conducted in 216 patients with severe or moderate head injury, with the aim of comparing the evolution of those that received only conventional treatment with the evolution of those treated with CDP-choline. Our results indicate that CDP-choline improves the global outcome of patients. We have found a trend towards a greater improvement in motor, cognitive and psychic alterations in the patients treated with CDP-choline, as well as a shortening of the stay in the hospital ward in the patients receiving this drug that initially presented with severe head injuries.

Adolescent↗

PubMed1991

Glucose: a more powerful modulator of fructose 2,6-bisphosphate levels than insulin in human hepatocytes.

This study provides the first experimental evidence of the short-term control of fructose 2,6-bisphosphate (Fru(2,6)P2) levels in adult human hepatocytes. (1) In hepatocytes whose metabolic status resembles the fed state (glycogen-rich), exposure to glucagon (10(-8) M) caused a drastic decrease in the levels of this effector and a significant fall in lactate production rate. Adrenaline, isoprenaline (a beta-adrenergic agonist) and lactate exerted a similar action decreasing Fru(2,6)P2 concentration. (2) In glucagon pre-treated, glycogen- and Fru(2,6)P2-depleted cells (a situation that mimics the fasted state), Fru(2,6)P2 re-synthesis was strictly dependent on glucose availability. (3) Insulin did not seem to exert a direct action on the control of Fru(2,6)P2 in human hepatocytes. The hormone--which failed to enhance Fru(2,6)P2 in glucose-starved cells--did not further increase Fru(2,6)P2 content nor its time-course evolution as compared to hepatocytes incubated with glucose alone. (4) Lactate caused a significant delay in the glucose-induced increase in Fru(2,6)P2 content that could not be prevented by insulin. (5) Data indicate that in human hepatocytes glucose is a more powerful modulator of Fru(2,6)P2 than insulin, and that variations in blood lactate concentration may also play a role in the control of hepatic Fru(2,6)P2 levels during the fasted-to-fed transition in humans.

Cells, Cultured↗

PubMed1996

Differential progression of complex culprit stenoses in patients with stable and unstable angina pectoris.

OBJECTIVES: This study sought to compare the evolution of complex culprit stenoses in patients with stable and those with unstable angina pectoris. BACKGROUND: Complex coronary stenoses are associated with adverse clinical and angiographic outcomes. However, it is not known whether the evolution of complex stenoses differs in unstable angina versus stable angina pectoris. METHODS: We prospectively assessed stenosis progression in 95 patients with unstable angina whose angina stabilized with medical therapy (Group 1) and 200 patients presenting with stable angina (Group 2). After diagnostic angiography, all patients were placed on a waiting list for coronary angioplasty and restudied at 8 +/- 4 (mean +/- SD) months later. In each patient the presumed culprit stenosis was identified and classified as complex (irregular borders, overhanging edges or thrombus) or smooth (absence of complex features). Stenosis progression, as assessed by computerized angiography, was defined as > or = 20% diameter reduction or new total occlusion. RESULTS: At the first angiogram, 364 stenoses > or = 50% and 383 stenoses < 50% were identified. At restudy, 36 (15%) of 236 stenoses progressed in 29 Group 1 patients and 36 (7%) of 502 stenoses in 31 Group 2 patients (p = 0.001). Forty-five (88%) of 51 stenoses > or = 50% and 6 (29%) of 21 stenoses < 50% that progressed developed to total coronary occlusion (p = 0.001). More culprit stenoses progressed in Group 1 than in Group 2 (p = 0.006), whereas progression of nonculprit stenoses was not significantly different in both groups. Culprit complex stenoses progressed more frequently in Group 1 than in Group 2 (p = 0.01). During follow-up, 3 patients died (myocardial infarction), and 51 had a nonfatal coronary event. Culprit stenoses progressed in 15 (54%) of the 28 patients with a nonfatal coronary event in Group 1 and in 9 (39%) of 23 patients in Group 2 (p = NS). Complex morphology (p < 0.001) and unstable angina at initial presentation (p < 0.01) were predictive factors for progression of culprit stenoses. CONCLUSIONS: A larger proportion of culprit complex stenoses progress in unstable angina than stable angina, and this is frequently associated with recurrence of coronary events.

Adult↗

PubMed1989

The position of the dentition in the mandible and its possible relation to orthodontic abnormalities.

A method used to study human evolution has compared different positions of the lower dentition in relation to the position of the mandibular condyle in the sagittal plane. The method is modified here and, with data from the Burlington Growth Study, used to describe a normal range of positions for the human lower dentition in relation to the condyle from the ages of 4 to 20 years. Measurements of a randomly selected group of orthodontically treated patients showed that in about one half of them the lower dentition was outside the normal range before treatment. The effect of treatment was to move the dentition randomly toward or away from a normal position. It is concluded that the new cephalometric measurement described here could help in the diagnosis and treatment of orthodontic patients.

Adolescent↗

PubMed1989

[Comparison of blood pressure profiles with flunitrazepam/fentanyl/nitrous oxide vs cervical epidural anesthesia in surgery of the carotid artery].

A study was carried out to compare the evolution of arterial blood pressure during carotid endarterectomy performed under either general anaesthesia (GA) or cervical epidural anaesthesia (CEA). 20 patients were randomly assigned to two equal groups. In the CEA group, 15 ml of 0.375% bupivacaine and 150 micrograms fentanyl were injected into the epidural space at C7-D1 level. In the GA group, patients were anaesthetized with 0.2 mg.kg-1 flunitrazepam and 5 micrograms.kg-1 fentanyl; intubation was carried out using 0.08 mg.kg-1 vecuronium, and the patients were ventilated with a mixture of nitrous oxide and oxygen (50% of each). Further injections, every 30 min, of 2 micrograms.kg-1 fentanyl were given to the patients in group GA. Blood pressure was monitored continuously, up to 4 h postoperatively, with a radial arterial catheter. Per- or postoperative hypertension was defined as a rise in systolic arterial blood pressure (Pasys) over 180 mmHg for greater than 3 min; this was treated with 20 mg nifedipine intranasally (group CEA) or 100 micrograms fentanyl with 0.5 mg flunitrazepam with or without nifedipine (group GA). Per- or postoperative hypotension was defined as a fall in Pasys below 100 mmHg and or a 30% fall in mean arterial blood pressure for greater than 3 min; this was treated, in both groups, with an intravenous bolus of 3 mg ephedrine. Patients in group CEA experienced more frequent episodes of peroperative hypertension (8/2; p less than 0.02) and postoperative hypotension (5/1) than group GA.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1996

[Mental prognosis in scaphocephaly].

BACKGROUND: The mental prognosis of scaphocephaly remains a controversial issue, and surgery is performed for functional or aesthetical reasons without clear evidence in the literature of which is the most important. PATIENTS AND METHODS: Three hundred and ninety six children with scaphocephaly were prospectively studied to analyse the correlation between age, intracranial pressure (ICP) and mental outcome. Before any treatment, the intracranial pressure was recorded (systematically during the first period of the study); the mental level was evaluated at first consultation and after a mean five-year follow-up. The mental evolution was compared whether the child was operated or not. RESULTS: The mental outcome of the patients was good in most of the cases whether or not they had been operated. There were significantly more normal patients in the scaphocephalies seen before one year of age at first consultation (P < 0.001) than in those seen after one year of age. There were significantly more abnormally high intracranial pressure cases in the group of patients who were seen later than one year of age (P = 0.0015). There were more retarded patients in the group with increased ICP, but the difference was not significant (P = 0.17). There was no correlations between ICP and final IQ neither in operated nor in non-operated patients. Conversely, a correlation was found between the early and late psychometric assessments in all patients. CONCLUSIONS: The main predictive factor of mental outcome appears to be the initial developmental level. Since the mental level was worse in the older children, and since the surgery does not influence the functional outcome when the initial mental level is low, we can conclude that the indication to perform surgery in scaphocephaly is sometimes not only a cosmetic problem.

Child Development↗

PubMed1994

Differences in P element population dynamics between the sibling species Drosophila melanogaster and Drosophila simulans.

Patterns of P element establishment and evolution were compared in populations of D. melanogaster and D. simulans. For each species, mixed populations were initiated with M strain flies lacking P elements together with P strain flies having similar P element copy numbers and phenotypes. The mixed populations were subsequently maintained under similar environmental conditions. On the basis of gonadal sterility assays, P elements tended to be significantly more active in D. melanogaster than in D. simulans populations. This activity difference between the two species was positively associated with P element copy number, determined by restriction enzyme analysis, and transposition frequency, as determined by a transposition assay. Host factors are the most likely explanation for the observed species variation. Difficulty of establishment may be a factor determining the absence of P elements in natural populations of D. simulans.

Animals↗

PubMed1993

Reconstructing the evolution of mind.

Since Darwin, the idea of intellectual continuity has gripped comparative psychology. Psychological evolution has been viewed as the accumulation of gradual changes over time, resulting in an unbroken chain of mental capacities throughout the diversity of life. Some researchers have even maintained that no fundamental psychological differences exist among species. An alternative model argues that a rather profound new psychology related to mental state attribution may have evolved recently in the primate order. The author explores recent experimental research from chimpanzees, rhesus monkeys, and children that is consistent with this second model of psychological evolution. Drawing on the fields of developmental, comparative, and social psychology, as well as evolutionary and developmental biology, the author outlines a research agenda aimed at reconstructing the evolution of metacognition.

Animals↗

PubMed1996

Conjugated bile acids and intestinal flora during the preruminant stage in goat. Influence of a lamb milk replacer.

A total of 45 preruminant goats were fed either goat milk or a milk substitute to compare the evolution of taurine and glycine conjugated bile acids and the evolution of the intestinal flora during the first month of life. Samples of hepatic bile were obtained from kids of 1, 7, 14, 21, and 28 days old and conjugated bile acids were measured by high performance liquid chromatography. Bacterial flora were determined in 14 and 28 day old animals. Ours results show that under our experimental conditions tauroconjugated bile acids clearly predominated over the conjugated with glycine. This pattern of preferential tauroconjugation persisted at all ages tested and in both groups studied. On the other hand, it seems that the quality of the protein and fat used in the elaboration of the milk replacer affects the intestinal flora and the postnatal evolution of conjugated bile acids.

Animals↗

PubMed1994

Evolution of the tenascin family--implications for function of the C-terminal fibrinogen-like domain.

The three members of the tenascin (TN) family, TN-C, TN-R, and TN-X, are apparently conserved in all vertebrates and therefore must have functions that contribute to survival. One specific domain of tenascins, the fibrinogen-like terminal knob, can be argued to have an essential function. Its position at the C-terminus makes it most vulnerable to loss through mutation or deletion, and it should have been eliminated in evolution if there were no selective pressure to maintain it. The epidermal growth factor and fibronectin III domains probably play an important role as spacers, placing the terminal knob at the end of the tribrachion or hexabrachion arms. In addition to functioning as spacers, at least some of these domains may have additional functional interactions. The conservation of these domains in evolution is comparable to that of some growth factors, consistent with this possibility. A phylogenetic tree of all known fibrinogen-related domains, including those in tenascins, is presented.

Animals↗

PubMed2026

Parallel evolutionary trajectories rewire enteropathogenic Escherichia coli adhesion to restore host attachment.

Enteropathogenic Escherichia coli (EPEC) causes disease in children, presenting as chronic diarrhea that can impair physical and cognitive development. The attachment of typical EPEC (tEPEC) to the gut epithelium via bundle-forming pili (BFP) is a key factor in its virulence. Yet, infections by atypical EPEC (aEPEC), which lack BFP, have become increasingly common. To investigate how aEPEC recover host-attachment in the absence of BFP, we performed experimental evolution using a non-adherent E. coli, constructed to mimic the ancestor of aEPEC, and selected adherent progeny. Highly adherent variants evolved through phase-variable activation of type I fimbriae (T1F), followed by two alternative trajectories: bacterial filamentation, which increases T1F avidity, or point mutations in the T1F adhesin FimH that enhance ligand affinity. Extending our analysis to the genomes of 327 aEPEC strains isolated from infected patients revealed that similar FimH mutations are common. We further demonstrated experimentally that these naturally occurring variants often increase epithelial-attachment. Our findings implicate T1F in aEPEC pathogenesis and suggest it may be clinically relevant for anti-adhesion therapy. More broadly, these results indicate that impaired host-attachment can be rapidly compensated by upregulating and optimizing an alternative adhesin, and that combining experimental evolution with comparative genomics can reveal evolutionary trajectories occurring in nature.

Bacterial Adhesion↗