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Results for “systematic evolution”

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PubMed1999

Repair of paraesophageal hernias.

BACKGROUND: Three years ago we proposed the use of laparoscopy and systematic addition of an antireflux procedure to repair paraesophageal hernias. We now present an analysis of the outcome on patients and the evolution of the technique proposed. METHODS: Symptoms and esophageal function were prospectively collected and followed in 41 consecutive patients treated over a 4-year period. Indications for repair included chronic anemia in 15 patients, and previous incarceration in 8. Twenty-two patients had symptoms of reflux. RESULTS: All operations were started laparoscopically, two were converted. Mean operating time was 210 minutes, and mean hospital stay was 4 days. Mean follow-up was 3 years. The operation was effective; all symptoms had improved significantly at last follow-up. CONCLUSIONS: Laparoscopic repair of paraesophageal hernia with the addition of an antireflux procedure, although difficult, lengthy, and not totally without risk, improves symptoms substantially, resolves anemia, and prevents incarceration in nearly all patients.

Adult↗

PubMed2001

UV-irradiated biodegradability of ethylene--propylene copolymers, LDPE, and I-PP in composting and culture environments.

The biodegradability of UV-irradiated films of ethylene--propylene copolymers (E--P copolymer), isotactic polypropylene (i-PP), and low-density polyethylene (LDPE), was measured in composting and culture environments by monitoring the variations in intrinsic viscosity [eta], weight loss per surface area, surface changes by SEM, colonization of fungus, chain scission, and evolution of hydroxyl and carbonyl groups by FT-IR spectroscopy. Photooxidation was used as a pretreatment for biodegradation of polymers. A systematic decrease in intrinsic viscosity [eta] and increase in carbonyl/hydroxyl regions in FT-IR spectra was found from 0 to 100-h irradiated samples. The degradation rate was strongly dependent on the composition of copolymers and markedly increased with decrease in ethylene content. Important surface erosion was detected after composting by SEM for longer UV-irradiated samples. It was estimated that chain-scission was directly related to photoirradiation.

Biocompatible Materials↗

PubMed2002

Single-crystalline star-shaped nanocrystals and their evolution: programming the geometry of nano-building blocks.

We demonstrate a novel synthetic scheme that can be used to differentially guide the shape of PbS semiconductor nanocrystals. Our study first demonstrates the discovery of single-crystalline star-shaped nanocrystals as novel transient species. We then carefully probe their shape evolution toward other novel nanostructures (e.g., tadpole-, L-, T-, cross-shapes, highly faceted star shapes, truncated octahedrons and cubes, etc.) and systematically elucidate the key parameters that control these final structures. In principle, through programming these growth parameters, the desired architecture of building blocks of other kinds of nano materials can be constructed.

Journal Article↗

PubMed2006

Tenrec phylogeny and the noninvasive extraction of nuclear DNA.

Due in part to scarcity of material, no published study has yet cladistically addressed the systematics of living and fossil Tenrecidae (Mammalia, Afrotheria). Using a noninvasive technique for sampling nuclear DNA from museum specimens, we investigate the evolution of the Tenrecidae and assess the extent to which tenrecids fit patterns of relationships proposed for other terrestrial mammals on Madagascar. Application of several tree-reconstruction techniques on sequences of the nuclear growth hormone receptor gene and morphological data for all recognized tenrecid genera supports monophyly of Malagasy tenrecids to the exclusion of the two living African genera. However, both parsimony and Bayesian methods favor a close relationship between fossil African tenrecs and the Malagasy Geogale, supporting the hypothesis of island paraphyly, but not polyphyly. More generally, the noninvasive extraction technique can be applied with minimal risk to rare/unique specimens and, by better utilizing museum collections for genetic work, can greatly mitigate field expenses and disturbance of natural populations.

Animals↗

PubMed2001

Capture of DNA sequences at double-strand breaks in mammalian chromosomes.

To study double-strand break (DSB)-induced mutations in mammalian chromosomes, we transfected thymidine kinase (tk)-deficient mouse fibroblasts with a DNA substrate containing a recognition site for yeast endonuclease I-SceI embedded within a functional tk gene. To introduce a genomic DSB, cells were electroporated with a plasmid expressing endonuclease I-SceI, and clones that had lost tk function were selected. Among 253 clones analyzed, 78% displayed small deletions or insertions of several nucleotides at the DSB site. Surprisingly, approximately 8% of recovered mutations involved the capture of one or more DNA fragments. Among 21 clones that had captured DNA, 10 harbored a specific segment of the I-SceI expression plasmid mapping between two replication origins on the plasmid. Four clones had captured a long terminal repeat sequence from an intracisternal A particle (an endogenous retrovirus-like sequence) and one had captured what appears to be a cDNA copy of a moderately repetitive B2 sequence. Additional clones displayed segments of the tk gene and/or microsatellite sequences copied into the DSB. This first systematic study of DNA capture at DSBs in a mammalian genome suggests that DSB repair may play a considerable role in the evolution of eukaryotic genomes.

Animals↗

PubMed2006

A newly recognized fossil coelacanth highlights the early morphological diversification of the clade.

Previously considered an actinopterygian or an osteichthyan incertae sedis, the Devonian (Givetian-Frasnian) Holopterygius nudus is reinterpreted as a coelacanth. This genus is among the oldest coelacanths known from articulated remains, but its eel-like morphology marks a considerable departure from the conventional coelacanth body plan. A cladistic analysis places Holopterygius as the sister taxon of the Carboniferous (Serpukhovian) genus Allenypterus. Despite the specialized morphology of these genera, they occupy a surprisingly basal position in coelacanth phylogeny; only Diplocercides and Miguashaia are further removed from the crown. A morphometric analysis reveals that coelacanths were anatomically disparate early in their history. Conflicts between this result and those of previous studies challenge the adequacy of systematic character sets for describing historical patterns of morphological variety. Coelacanths have long had an iconic place in the study of vertebrate evolution for their apparent anatomical conservatism over geological time, but Holopterygius provides clear evidence for rapid morphological evolution early in the history of this clade.

Animals↗

PubMed1989

Search for optimal frequencies and amplitudes of therapeutic electrical carotid sinus nerve stimulation by application of the evolution strategy.

In humans, electrical, bipolar, bilateral carotid sinus nerve stimulation (CSNS; impulse duration 0.35 ms) was applied, using frequencies between 10 and 110 Hz and voltages between individual thresholds and maximal amplitudes of stimulation. Ten anginal patients and two hypertensive patients were studied at an interval of up to 12 years after implantation of electrodes and a radiofrequency receiver for chronic therapeutic CSNS. In search of combinations of frequency and voltage of CSNS, eliciting largest ("optimal") depressor responses of blood pressure and heart rate in the individual patient, Rechenberg's evolution strategy was applied. This strategy simulates mutation and selection of biological evolution. In each patient and on each test stimulation, a value of quality was computed from actual heart rate and blood pressure values as a selection criterion for the strategy. Either responses to uninterrupted CSNS were investigated, while stimulation parameters were adjusted every 3 min, according to the strategy, or responses to 3 min of CSNS after a change in stimulation parameters were compared to intercalated 3-min control periods. In each patient, one or more combined settings of frequency and voltage elicited "optimal" responses. In principle, "optimal" CSNS frequencies ranged between 35 and 105 Hz with large interindividual differences. Due to chronic implantation of electrodes and technical features of radiofrequency transmitted stimulation energy, interindividually different voltages led to an optimal response to CSNS. Also according to the present results, the frequency of CSNS has to be determined individually. It is concluded that the evolution strategy was applied successfully, because voltage and frequency settings leading to "optimal" responses were found within 90-180 min, whereas intraindividual systematic investigations would not be feasible due to their necessarily very long duration. So far, only short-term responses have been evaluated. A broader use of the strategy in other applications is encouraged, as for example in pacemaker optimization and especially in functional electrostimulation.

Adult↗

PubMed1976

Role of chronic hepatitis in development of thalassaemic liver disease.

Liver function and the presence of HBsAg and anti-HBsAg were studied in 90 hypertransfused thalassaemic children. Increased serum transaminases were found in 62 patients, and persisted from more than 6 months in 45 cases. Liver biopsy in this latter group led to a diagnosis of 14 cases of chronic persistent hepatitis, 9 cases of aggressive hepatitis, and 3 cases of hepatic fibrosis. In Italy thalassaemic children undergoing hypertransfusion therapy frequently encounter SH virus infection, with a consequent hepatitis that is generally anicteric and unrecognized unless systematically sought. In a liver already stressed by the concomitant iron overload, hepatitis infection might thus play a key role in the evolution of cirrhosis which frequently affects thalassaemics.

Adolescent↗

PubMed2026

'PePApipe': A complete bioinformatics analysis pipeline for African Swine Fever Virus genome.

African Swine Fever Virus (ASFV) is of high concern in porcine livestock across the world due to both the high mortality rates and the trade restrictions imposed on affected regions. The viral genome is large and complex, and genomic analysis is essential for tracing its origin and evolution. Although several bioinformatics tools exist for genome assembly and analysis, no single platform integrates all necessary steps in an accessible and systematic way. In this study the authors developed 'PePApipe', a custom-built, user-friendly pipeline that enables rapid, complete, and efficient ASFV genome analysis. It is specifically designed for laboratory professionals with limited bioinformatics experience, requiring only basic command-line knowledge. Starting from raw sequencing data, PePApipe integrates thirteen software tools into one automated workflow, covering quality control and pre-processing of raw reads, de novo genome assembly and variant calling. Programmed in Python, it can be executed locally through bash scripts, or using a Slurm protocol for batch processing of multiple samples. The main outputs are the ASFV consensus genome sequence and a file listing its putative variants compared to the selected reference genome. PePApipe classifies generated files into structured folders and produces intermediate files that can be used as inputs for further or parallel analyses; users can also enable or disable specific steps in each particular case. This pipeline is adaptable and complementary to downstream steps such as viral genome annotation or genome visualization. By consolidating all stages of viral genome analysis into a single automated workflow, PePApipe reduces the likelihood of user error, and enhances reproducibility and efficiency. This user-friendly pipeline facilitates the transition from sequencing to assembly and downstream analysis of viral genomes, ensuring a fast and reliable response to molecular analysis demands. Finally, the pipeline can be easily adapted to the study of other viral species, expanding its application in infectious diseases surveillance.

African Swine Fever Virus↗

PubMed1976

[Toxoplasmosis and chronic myeloid leukemia].

A patient suffering from chronic myeloid leukemia and used as a donor of leucocytes was found to have toxoplasmosis associated with a high level of IgG without an elevation of IgM which was maintained for several months. This case raises several points for discussion. Toxoplasmosis is a frequent complication of malignant hematological disease, it is often severe with neurological complications in more than half the patients affected. It is often difficult to diagnose. The parasite is arduous to isolate and serology is problematic to interpretate without reference to previous samples. This suggests it would be wise to measure the titre of anti-toxoplasma antibodies as part of the initial investigations of every malignant hemopathy and to repeat the measurements during the evolution of the disease. Any patient showing a high serological titre, even though it is stable and without IgM should be given systematically a specific treatment for toxoplasmosis, for as in the patient presented in this paper, such a serological picture is compatible with an increasing infection. The frequence of high serological titres seems to be greater among patients suffering from chronic myeloid leukemia than among another people. Then, transfusion of leucocytes of such patients may be the source of parasite transmission; this paper relates one case of post-transfusional toxoplasmosis.

Antibodies↗

PubMed2000

Towards evidence-based health administration education: the tasks ahead.

The vision of a more objective, patient-oriented and quantitative evaluation of medicine motivates much current activity in health care, and has come to be called "evidence-based" medicine (Atkins, Kamerow and Eisenberg 1998). A similar vision underlies this special issue. It derives from the 1998 AUPHA annual meeting theme of teaching management technology and the work of an AUPHA task force. The task force is seeking support for a collaborative program to develop measures of educational outcomes and use them in the systematic improvement of member programs (Stephen F. Loebs, PhD, Chair. Members include Ray Davis, PhD; Jeptha W. Dalston, PhD; Gary Filerman, PhD; Barry Greene, PhD; the author; and Douglas Wakefield, PhD.) The task force calls this effort "evidence-based health administration education." It intends a systematic, outcomes-oriented, evaluation and improvement of the educational process, as the evidence-based medicine movement does of medical care. Evolution of member programs using measured performance and continuous improvement is implied, rather than dramatic change (Griffith 1998). Just as evidence-based medicine relies on a disease-oriented taxonomy, evidence-based education must rely on an agreed-upon set of specific skills, knowledge, and abilities (SKAs) that can be learned by students and tested in graduates. This paper discusses what lessons can be learned from the papers reported in the issue, identifies the components necessary to implement the vision, and suggests how AUPHA can proceed in the near future to implement evidence-based education.

Education, Professional↗

PubMed2002

A theory on the evolution of the habitual orthograde human bipedalism--the "Amphibische Generalistentheorie".

The theory is formulated that ubiquitous scarcity of energy is one of the main motors of evolution. It is concluded that our primate ancestors never came down from the trees, but rather they have always been (semi-)terrestrial. This habit is probably an old symplesiomorph trait, older than primates themselves. Terrestrial habits in primates correlate to body weight in small systematic groups (e.g., large genera, families) but are, overall, completely independent from individual body mass. An omnivorous, semiterrestrial quadrupedal locomotor generalist seems to be the most probable morpho- and eco-type for our ancestor at the threshold of a hominoid stage of our evolution. The theory presented here suggests that our hominoid ancestor lived in gallery forests and changed strata in order also to inhabit the savannah habitat as well as the shallow water of the rivers or coasts. Foraging in a wading manner was extremely favourable for an effective and, especially, seasonally independent, animal protein supply. Anatomical adaptations to orthogradism and proportions of the extremities are discussed in relation to the necessary and frequent change of habitat strata. Ultimately, human bipedalism is seen here to be derived as a consequence of the centre of body mass, which is, in primates, near the hind extremities. By contrast to other mammals entering the water, wading primates sink back on their hind limbs. Selective forces for habitat use, limb proportions and wading habits are discussed, as well as the phylogenetic origin of human affinity to water and shores in all peoples through all times, from australopithecine times through the Paleolithic until today.

Animals↗

PubMed1984

[A case of intestinal occlusion caused by a Meckel' diverticulum (etiopathogenetic, diagnostic and clinical considerations)].

The authors show a case of acute intestinal stoppage due to Meckel's diverticulum. After some notices about embryogenesis, pathological anatomy and symptomatology of Meckel's diverticula, they point out the difficulty to reach the diagnosis of such disease, which almost always is only done subsequent to the appearance of complications, such as: intestinal stoppage, inflammation, ulceration, perforation, neoplasms, bleeding. In fact, the diagnosis of Meckel's diverticulum is exceptionally preoperative and difficult on the basis of the symptomatology only, for which the disease can be responsible, whereas it can be more easily placed thanks to the contribution of instrumental methods, such as: barium meal, opaque enema, scintigraphy with 99mNa pertechnetate, selective arteriography of upper mesenterial artery. The diagnosis is more frequently interoperative, in course of explorative laparotomy or performed for other indications. Then the Authors state their orientation about the treatment, which is surgical in all the complex cases of Meckel's diverticulum, with a mention of the different operative techniques, and, as a conclusion, confirm the necessity for the systematic research of the asymptomatic diverticulum, the removal of which represents the only prophylactic measure against a permanent possibility and dreadful complicative evolution of same.

Humans↗

PubMed1993

Changes in the gastric mucosa following eradication of Helicobacter pylori.

Although most studies reporting on the examination of Helicobacter pylori infection have focused on the clearance of the bacteria and the rapid disappearance of the neutrophil infiltrates, the evolution of inflammatory and architectural changes in the antral and corporal mucosa following the eradication of H. pylori has not been addressed systematically. This study examines in detail the histopathologic appearance of the antral and corporal mucosa in a group of patients infected with H. pylori and follows the spectrum of morphologic changes in each of them after the eradication of the infection. At least 11 biopsies ("gastric mapping") were obtained from the antrum and body of each of 15 patients with H. pylori. Complete mapping was then repeated 1, 4, and 10 to 12 mo after the eradication of H. pylori by a course of "triple therapy." Each biopsy was assessed in a semi-quantitative fashion for presence of H. pylori, neutrophils, eosinophils, lymphocytes, lymphoid follicles, and intestinal metaplasia. Other features (integrity of surface epithelium, architecture, fibrosis) were evaluated descriptively. Results were compared with those obtained from a control group of 16 uninfected, healthy adult volunteers. H. pylori infection was eradicated in 11 subjects. The disappearance of neutrophils and the normalization of the surface epithelium closely paralleled that of H. pylori. Persistence of even small numbers of neutrophils was a predictor of relapse. Eosinophils and lymphocytes decreased slowly and did not return to normal levels within 1 yr. Lymphoid follicles decreased very slowly in all patients but were still present in all gastric locations at one year after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2006

Temporal evolution of 2-dimensional direction signals used to guide eye movements.

The smooth pursuit system must integrate many local motion measurements into a coherent estimate of target velocity. Several laboratories have studied this integration process using eye movements elicited by targets, such as tilted bars, containing conflicts between local motion signals measured along contours [one dimensional (1D)] and those measured at the bar's endpoints, or terminators [two dimensional (2D)]. The general finding is that 1D signals dominate early responses, whereas later components of the behavior are determined by 2D signals. We studied the dynamics of the integration process in macaque monkeys by systematically varying the relative proportions of 1D and 2D signals and the retinal eccentricities at which they appeared. Predictably, longer bars produced greater and longer-lasting contour-induced deviations. The evolution of the 2D response occurred over a period of 50-400 ms, depending on the relative proportions of 1D and 2D signals. As contours were displaced from the fovea the deviation decreased but much less so for early (1st 40 ms) than for late (subsequent 40 ms) pursuit initiation. These bottom-up effects could be overcome to a limited extent by the top-down influence of predictability. Finally, we observed that when animals were free to track any part of the bar, they spontaneously made short-latency saccades to the terminators on most trials, especially when the bars were tilted. This suggests an increased saliency of moving terminators, particularly when discrepancies exist among local motion signals.

Adaptation, Ocular↗

PubMed2005

Insight into the phylogeny of African Clariidae (Teleostei, Siluriformes): implications for their body shape evolution, biogeography, and taxonomy.

The phylogenetic relationships among Clariidae species (Teleostei, Siluriformes) were assessed using 563 nucleotides of the cytochrome b mitochondrial gene. We included 32 Clariidae species representative of seven genera in our analysis. Hetropneustes fossilis (Heteropneustidae) and Clarotes laticeps (Claroteidae) were used as outgroups. The molecular data identified two evolutionary lineages that correspond on one hand to African species and on the other hand to Asian species. Morphological and osteological evolution in Clariidae did not follow an orthogenetic series. Species with robust body, strong ossified head, and large adipose fin were not ancestral ones and eel-like species were not phylogenetically related and represent independent adaptation to life in mud. Adaptation to life in deep water occurred two times independently in lake Tanganyika (with Dinotopterus cunningtoni) and in Lake Malawi (with Bathyclarias species). Molecular dating using a molecular clock of 1% divergence per million years and a comparison with fossils records allowed an estimate of the timing of cladogenesis within the species studied. The Clariidae family originated in Asia 50 MY ago but contemporary African and Asian studied species originated from a common ancestor that was present on the Arabian plate about 15 MY ago. Systematic implications of these results are also discussed.

Africa↗

PubMed1986

[Is systematic syphilis serology still useful in a department of internal medicine? A one-year prospective study using a diagnostic and therapeutic decision algorithm].

During one year syphilis serology was systematically studied, using the TPHA and VDRL tests, in each of the 1,279 patients hospitalized in an Internal Medicine department. In all cases diagnosis and treatment were analyzed by means of a decision algorithm. Only 37 patients were found to have one or both serological tests positive. No evolutive syphilis was observed, and none of these positive tests was contributive to the diagnosis of another disease. Only 14 patients received a specific antibiotic treatment on the grounds that their positive test confirmed a late asymptomatic syphilis. We conclude that systematic syphilis serological tests are not useful in an Internal Medicine department, except in some patients epidemiologically at high risk of syphilis.

Algorithms↗

PubMed2026

Systematic mining and characterization of metal transporter families regulating zinc homeostasis provide insights into metal homeostasis in Camellia sinensis.

BACKGROUND AND AIMS: Zinc is essential for tea plant growth and quality formation, yet its homeostatic mechanisms remain poorly understood. This study identified metal transporter families regulating zinc homeostasis, analyzed their evolution, structure, and expression, and clarified zinc uptake, transport, detoxification networks, and their links to metabolism. METHODS: This study identified zinc homeostasis-related metal transporter families in the tea plant genome, characterized their structural features and expression profiles across tissues and developmental stages through integrative bioinformatics and transcriptomic analyses, and delineated the molecular mechanisms underlying zinc uptake, translocation, and detoxification by systematically integrating published evidence. RESULTS: This study identified 74 metal transporter genes from six families: 13 CsZIPs, 12 CsNRAMPs, 10 CsHMAs, 10 CsYSLs, 14 CsMTPs, and 15 CsCAXs in the 'Shuchazao2' genome, revealing closer affinity to woody species than to Arabidopsis. These proteins exhibit conserved domains, diverse subcellular localizations (cell membrane, vacuole, chloroplast, and Golgi apparatus), and tissue-specific expression with abundant stress/hormone-responsive cis-elements. At the plant-soil interface, tea plants mobilize rhizospheric zinc via proton and organic acid secretion; CsYSLs, CsNRAMPs, and CsZIPs mediate zinc uptake, aided by arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) that expand root absorption zones. Xylem CsHMAs and phloem CsYSLs coordinate root-to-shoot zinc translocation, and vacuolar transporters (CsMTPs, CsCAXs), cell wall immobilization, and antioxidant systems alleviate high-zinc stress injury. CONCLUSIONS: These findings collectively delineate an integrated zinc "acquisition-distribution-buffering" network in tea plants, offering a repertoire of candidate genes with potential utility in zinc biofortification breeding and improving acid soil adaptation. Further experimental validation, including tea transgenesis, zinc-stress qRT-PCR, and heterologous functional complementation, is essential to substantiate their biological roles.

Camellia sinensis↗