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Results for “Comparative evolution”

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PubMedDate not supplied

[The late evolution of bronchial asthma appearing in children].

A retrospective study was performed in order to compare the clinical evolution of chronic bronchial asthma with onset in childhood with that of bronchial asthma registered at adult age. The group included 150 cases (87 females and 63 males) out of which 108 (72%) asthma with late onset and 42 (28%) asthma symptoms registered in childhood and adolescence. The symptoms were: allergic rhinitis and spastic tracheobronchitis in 18 (42.8%), dyspneic recurrent bronchitis in 16 (38%), nasal polyposis in 4 (9.5%) and atopic dermatitis in 4 (9.5%) cases. A possible allergic etiology was not taken into consideration in these cases. According to the data obtained, it results that the evolution and the prognosis of bronchial asthma are more severe in patients with its onset in childhood, where there were noted: more severe clinical forms of the disease, higher ventilation dysfunction, more numerous social (family) consequences of the disease, and a higher necessity of long term, systemic corticotherapy than in cases of bronchial asthma with late onset. The delay in the preventive treatment or an incorrect application of it in childhood will condition to a great extent the unfavourable evolution of the disease.

Adrenal Cortex Hormones↗
PubMed1998

Retrospective study on the evolution of visual acuity after external beam radiotherapy (20 Gy, 2 Gy fractions) for subfoveal choroidal neovascular membranes in ARMD.

This is a retrospective study of 104 patients with a total follow-up between 12 and 48 months (mean follow-up of 24 months), in which the effect of External Beam Radiotherapy with a total dose of 20 Gy (2 Gy fractions) on the visual acuity of eyes affected by subfoveal choroidal neovascularization is evaluated. The evolution of the visual acuity of the irradiated eyes is compared with the evolution of the visual acuity of their fellow eyes which were also affected by choroidal neovascularization but were not treated or treated by laser photocoagulation. This study suggests that the effect of radiotherapy, with a total dose of 20 Gy, on the visual acuity of eyes affected by subfoveal choroidal neovascularization, seems to be not better than the natural course of choroidal neovascularization or the evolution after laser therapy.

Adult↗
PubMed2001

[Acute cholangitis caused by choledocholithiasis: traditional surgery or endoscopic biliary drainage].

BACKGROUND: Endoscopic drainage of the biliary tree for acute cholangitis is a therapeutic modality with a lower mortality and complication rates. AIM: To compare endoscopic drainage with surgical treatment in the emergency management of acute cholangitis. PATIENTS AND METHODS: Between 1995 and 1998, sixty five patients with acute cholangitis were subjected to an endoscopic drainage of the biliary tree. In the same period, 40 patients were treated with traditional surgical procedures. The evolution of both groups of patients were compared. RESULTS: Sixty two patients (95.4%) subjected to endoscopic treatment had a satisfactory evolution, compared with 23 (58%) of those operated (p < 0.001). Five operated patients and no individual subjected to endoscopic drainage died (p < 0.01). Mean postoperative hospital stay of operated patients was 15.5 +/- 19.6 days compared to 5.8 +/- 4.2 days in those subjected to endoscopic drainage (p < 0.001). Definitive resolution of biliary obstruction was achieved in 83% of patients subjected to endoscopic drainage or traditional surgery. CONCLUSIONS: Endoscopic drainage has a lower rate of complications and mortality than traditional surgery, in the treatment of acute cholangitis.

Acute Disease↗
PubMed1987

[Horton's disease and rhizomelic pseudopolyarthritis. Developmental data apropos of 95 cases].

The many common factors linking rhizomelic pseudopolyarthritis and Horton's disease prompt to compare their respective evolutions and the long-term results of their treatments. The comparative study of 28 patients with temporal Horton's arteritis, proven histologically, and 28 rhizomelic pseudopolyarthritis without arteritis on biopsy, in a total population of 95 patients, confirms the similarity of their clinical and biological signs and show a closely related evolution in the three groups. The evolution leads to a cure approximately 16.4 +/- 14 months in 41 p. cent of the cases. 34 p. cent of the patients are at an advanced stage with a mean follow-up of 37 months and relapses during the weaning period were frequent. 25 p. cent of the patients died. Most deaths occur in the first month of the disease, and occur readily in patients who have received a short treatment with steroids discontinued because of a iatrogenic accident. Cerebral vascular accidents and coronary accidents, arterial hypertension and iatrogenic gastro-intestinal ulcerations are the most frequent complications.

Aged↗
PubMed2001

Evolutionary genomics of pathogenic bacteria.

Complete genome sequences are now available for multiple strains of several bacterial pathogens and comparative analysis of these sequences is providing important insights into the evolution of bacterial virulence. Recently, DNA microarray analysis of many strains of several pathogenic species has contributed to our understanding of bacterial diversity, evolution and pathogenesis. Comparative genomics has shown that pathogens such as Escherichia coli, Helicobacter pylori and Staphylococcus aureus contain extensive variation in gene content whereas Mycobacterium tuberculosis nucleotide divergence is very limited. Overall, these approaches are proving to be a powerful means of exploring bacterial diversity, and are providing an important framework for the analysis of the evolution of pathogenesis and the development of novel antimicrobial agents.

Bacteria↗
PubMed1997

A mammalian homologue of the Drosophila retinal degeneration B gene: implications for the evolution of phototransduction mechanisms.

Comparative analysis of homologous genes in distantly related species provides important insights into the evolution of complex physiological processes. The Drosophila retinal degeneration B (rdgB) gene encodes a protein involved in phototransduction in the fly. We have isolated a human gene, DRES9, and its murine homologue (Dres9), which show a high degree of similarity to the Drosophila rdgB gene. RNA in situ hybridization studies performed on mouse-embryo tissue sections at various developmental stages revealed that Dres9 is expressed at very high levels in the neural retina and in the central nervous system (CNS), similar to its Drosophila counterpart. The high level of sequence conservation and similarities in the expression patterns of rdgB and DRES9 during development in Drosophila and mammals indicate that Dres9 is the orthologue of RdgB, and strongly suggest a possible functional conservation of these proteins during evolution. DRES9 encodes a phosphatidylinositol-transfer protein, suggesting that phosphatidylinositol may have a role as an intracellular messenger in vertebrate phototransduction. The identification of this gene and the study of its expression pattern in mammals will help shed new light on the evolution of vision mechanisms and suggest DRES9 as a candidate gene for human retinopathies.

Amino Acid Sequence↗
PubMedDate not supplied

Metabolism of N-nitrosodimethyl- and N-nitrosodiethylamine by rat hepatocytes: effects of pretreatment with ethanol.

Hepatocytes were isolated from the livers of ethanol-pretreated rats, and the relationship between the generation of CO2 and the loss of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) from the incubation mixtures was examined. The evolution of CO2 by hepatocytes isolated from untreated, control rats was compared with the evolution of CO2 by hepatocytes isolated from rats treated with 10% EtOH in their drinking water. The CO2 generated from either NDMA or NDEA represented only a fraction of the parent compound that was metabolized during the incubation period. Therefore, the measurement of CO2 evolution as an indication of the metabolism of these simple dialkylnitrosamines is inadequate, and the actual loss of the parent compound must be measured directly when utilizing isolated hepatocytes as a model system to study the metabolism of nitrosamines. The liver microsomal metabolism of NDMA and NDEA was also examined. Pretreatment of the rats with ethanol resulted in a marked increase in the microsomal metabolism of NDMA but had a relatively small effect on NDEA metabolism. Phenobarbital pretreatment did not result in any increase in NDMA metabolism whereas there was a very significant (6-fold) increase in NDEA metabolism. These results suggest that different isozymes of cytochrome P-450 may be primarily responsible for the metabolism of the two nitrosamines. The inhibition patterns observed when an antibody inhibitory to cytochrome P-450j was added to microsomes derived from control and ethanol- and phenobarbital-pretreated rats conclusively demonstrate that NDMA and NDEA are preferentially metabolized by distinct isozymes of cytochrome P-450.

Alkylation↗
PubMed2026

Genome evolution and long-term demographic history in true crocodiles.

Reference-quality genomes remain scarce for true crocodiles (Crocodylus), limiting comparative analyses of genome evolution and demographic history. Here, we generated and analyzed 2 long-read genomes, 1 for Crocodylus intermedius and 1 for C. niloticus, to investigate genome architecture, coalescent effective population size (Ne), and patterns of molecular evolution across crocodilians. Comparative analyses revealed broadly similar repeat landscapes in both species and extensive macro-synteny with Alligator sinensis, indicating strong structural conservation across crocodilian genomes. Using phased diploid assemblies and MSMC2, we reconstructed historical Ne trajectories and found marked differences between species. Crocodylus intermedius exhibited persistently low Ne throughout most of the late Quaternary, with a pronounced decline during the Late Pleistocene-early Holocene transition. In contrast, C. niloticus showed substantially larger Ne over comparable time intervals. Genome-wide codon-based analyses identified significant heterogeneity in dN/dS (&#x3c9;) among crocodilian lineages. Crocodylus niloticus showed the lowest genome-wide &#x3c9;, whereas elevated values in C. intermedius and other lineages were consistent with reduced long-term efficacy of purifying selection under smaller historical population sizes. Branch-site tests identified candidate genes under positive selection in both focal species, with functional categories related to ion transport, endocrine regulation, and cellular signaling. Together, these results provide genomic resources for Crocodylus and support an association between long-term demographic history and genome-wide patterns of molecular evolution across crocodilians.

Animals↗
PubMed1996

Region-specific YAC banding and painting probes for comparative genome mapping: implications for the evolution of human chromosome 2.

To date, several hundred nonchimeric yeast artificial chromosomes (YACs) from the Centre d'Etude du Polymorphisme Humain containing polymorphic sequence-tagged sites have been mapped by fluoresence in situ hybridization (FISH) on human metaphase chromosomes. Because they carry an average of 1 Mb of human genomic DNA, CEPH YACs generate high-intensity in situ hybridization signals. The available set of cytogenetically and genetically anchored YACs, approximately one every 5-10 cM evenly spaced over almost the entire human genome, provides complex region-specific probes for molecular cytogenetics. YAC probes can be adapted with unlimited flexibility to specific FISH applications such as the study of chromosomal evolution. We have generated representational probes for YAC banding and painting of human chromosome 2 and its great ape homologs. Convergent inversions were found in the pericentric region of the gorilla and orangutan homologs of chromosome 2p.

Animals↗
PubMed1996

Inefficacy of collagen shields in the rabbit corneal wound-healing process.

A controlled study in the rabbit eye was performed to clarify the suitability of collagen shields in accelerating the wound healing process in damaged cornea. After a standardized bilateral keratectomy, the spontaneous evolution of the healing process in the right eye (control eye) was compared with the evolution in the left eye, treated with a collagen shield (a shield of the 12- or 24-h type). The healing area was measured by planimetry after fluorescein staining at 0, 24, 48, and 72 h after keratectomy. Histological and immunohistochemical analysis of the healing process was also performed. Reepithelization of the damaged cornea was almost complete at 72 h, and there were no differences in the time course of the healing process between control and treated eyes. There was an important polymorphonuclear infiltration in treated eyes, mainly composed of eosinophiles, which was not present in control eyes. This indicates a subacute inflammatory immunological reaction. It is concluded that the usefulness of collagen shields should be reappraised, especially in injured corneas.

Animals↗
PubMed2000

[Thomas H.Huxley--the naval doctor who became Darwin's bulldog].

Thomas H. Huxley (1825-1895) was an English physician and biologist who had a deep impact on the Victorian age. More than any other at his time he introduced scientifically based values. As a member of London's school board he brought science into the curriculum, encouraging school-children to ask questions and to make their own observations. Huxley came from a lower middle class family with little money. By sheer determination and hard work he managed to get a medical education at Charing Cross Hospital Medical School. He then obtained a posting on H.M.S. Rattlesnake, which gave him a chance to explore the southern seas and to study marine species. The results were published by the Royal Society of which Huxley became a member at the age of 26, and later its president. After several years of uncertainty he secured a position at the Royal School of Mines, which he transformed into the Imperial College of Science. He was a prolific scientist with wide interests, doing valuable work in paleontology, taxonomy and ethnology. Huxley wrote numerous essays on philosophy and scientific subjects. He coined the word agnostic to explain his attitude to Christian dogma. His style was clear and direct, and his essays still read very well. However, Huxley is now mostly, perhaps unfairly, remembered for his defence of Darwin's theory of evolution. In his book Evidence as to man's place in nature, Huxley, in contrast to Darwin, deals with the evolution of humans, mainly based on comparative anatomy. Huxley advocated a firmly held belief that scientific truths will have a liberating effect on the minds of men. His lectures on scientific subjects attracted large audiences of people who had not had the benefit of a higher education.

Anatomy, Comparative↗