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PubMed1983

[Computer bank of amino acid sequences of protein hormones. Comparative analysis of the sequences in pro-opio-melanocortin, proenkephalin and prodynorphin: detection of phorphin--the 4th repeating peptide in prodynorphin].

Using a BESM-6 computer, a computer system for accumulation and comparative analysis of amino acid sequences (AS) of protein-peptide hormones and their precursors (the so-called computer bank of protein hormone AS) was developed. A Fortran-based program designed for construction of correspondence schemes of AS and their local similarity profiles was elaborated. In combination with the previous programs this system allows a rapid inclusion of the newly deciphered sequences into the corresponding homologous groups, thus complementing the correspondence scheme and specifying the evolution profiles. A comparative analysis of AS in proopiomelanocortin (POMC), proenkephalin (PENK) and prodynorphin (PDIN) revealed evolutionary-conservative and variable sites. The conservative sites of AS are active centers of the hormones. The leu-enkephalin analog, phorphin, the fourth repeating peptide of this precursor, was detected in prodynorphin, which, similar to beta-neo-endorphin, dynorphin and rimorphin may possess a biological activity. The similarity of the effector sites of the melanotropin sequence from POMC to the met-enkephalin sequence from PENK and leu-enkephalin sequence from PDIN as well as to gastrin and cholecystokinin was established. This may suggest that the hormone-receptor complexes in target organs of these hormones are also similar.

Amino Acid Sequence↗
PubMed1998

Evolution of RPS4Y.

Sequence variation within RPS4Y, a ribosomal protein gene located in the nonpseudoautosomal region of the Y chromosome, was used to elucidate the origin of this gene in primates. Complete coding and additional flanking sequences (949 bp) of the RPS4Y locus were determined in four nonhuman primate species. Phylogenetic reconstruction of RPS4 sequence evolution supports the monophyly of mammalian RPS4 and RPS4Y. Molecular evolutionary rate estimation reveals significantly elevated rates of DNA and protein evolution in RPS4Y compared with its X-chromosome homologs. These rates enable us to estimate the timing of the transposition of RPS4X to the Y chromosome (95% confidence interval, 32 MYA-74 MYA), and this estimate was verified by Southern hybridization analysis of prosimian and simian genomic DNA. These data support a transposition event of ancestral primate RPS4X to the Y chromosome prior to the divergence of Prosimii.

Animals↗
PubMed1992

Brain-derived neurotrophic factor is more highly conserved in structure and function than nerve growth factor during vertebrate evolution.

Mammalian nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are members of a protein family with perfectly conserved domains arranged around the cysteine residues thought to stabilize an invariant three-dimensional scaffold in addition to distinct sequence motifs that convey different neuronal functions. To study their structural and functional conservation during evolution, we have compared NGF and BDNF from a lower vertebrate, the teleost fish Xiphophorus, with the mammalian homologues. Genomic clones encoding fish NGF and BDNF were isolated by cross-hybridization using probes from the cloned mammalian factors. Fish NGF and BDNF were expressed by means of recombinant vaccinia viruses, purified, and their neuronal survival specificities for different classes of neurons were found to mirror those of the mammalian factors. The half-maximal survival concentration for chick sensory neurons was 60 pg/ml for both fish and mammalian purified recombinant BDNF. However, the activity of recombinant fish NGF on both chick sensory and sympathetic neurons was 6 ng/ml, 75-fold lower than that of mouse NGF. The different functional conservation of NGF and BDNF is also reflected in their structures. The DNA-deduced amino acid sequences of processed mature fish NGF and BDNF showed, compared to mouse, 63% and 90% identity, respectively, indicating that NGF had reached an optimized structure later than BDNF. The retrograde extrapolation of these data indicates that NGF and BDNF evolved at strikingly different rates from a common ancestral gene about 600 million years ago. By RNA gel blot analysis NGF mRNA was detected during late embryonic development; BDNF was present in adult brain.

Amino Acid Sequence↗
PubMed2002

Does experimental evolution reflect patterns in natural populations? E. coli strains from long-term studies compared with wild isolates.

Our results show that experimental evolution mimics evolution in nature. In particular, only 1,000 generations of periodic recombination with immigrant genotypes is enough for linkage disequilibrium values in experimental populations to change from a maximum linkage value to a value similar to the one observed in wild strains of E. coli. Our analysis suggests an analogy between the recombination experiment and the evolutionary history of E. coli; the E. coli genome is a patchwork of genes laterally inserted in a common backbone, and the experimental E. coli chromosome is a patchwork where some sites are highly prone to recombination and others are very clonal. In addition, we propose a population model for wild E. coli where gene flow (recombination and migration) are an important source of genetic variation, and where certain hosts act as selective sieves; i.e., the host digestive system allows only certain strains to adhere and prosper as resident strains generating a particular microbiota in each host. Therefore we suggest that the strains from a wide range of wild hosts from different regions of the world may present an ecotypic structure where adaptation to the host may play an important role in the population structure.

Animals↗
PubMed1999

The evolution of visual cortex: where is V2?

A comparative analysis of the area of the cortex that is adjacent to the primary visual area (V1), indicates that the lateral extrastriate cortex of primitive mammals was likely to contain only a single visuotopically organized field, the second visual area (V2). Few, if any, other visual areas existed. The opposing hypothesis, that primitive mammals had a 'string' of small visual areas in the cortex lateral to V1 (as in some rodents), is not supported by studies of the organization of extrastriate cortex in other mammals, nor by the variability in this organization among extant rodents. A critical re-analysis of published evidence on the presence of multiple areas adjacent to V1 in some rodents has led to alternative interpretations of the organization of the areas in these regions.

Anatomy, Comparative↗
PubMed1999

Influence of methodology on the presence and extent of mismatching between 99mTc-MIBI and 123I-BMIPP in myocardial viability studies.

UNLABELLED: Discordant uptake (mismatching) of 123I-labeled beta-methyl-piodophenyl-pentadecanoic acid (BMIPP) less than 99mTc-labeled methoxyisobutyl isonitrile (MIBI) is a good predictor of myocardial viability. However, methodological factors can influence assessment of the presence of mismatching because of differences in background activity between the tracers. In this study, we investigated the influence of methodological parameters on the mismatching between BMIPP and MIBI in patients with chronic ischemic heart disease. METHODS: Polar maps were created to quantify the extent of mismatched tissue measured in 10 patients with myocardial infarction according to three methods for data processing: no correction, subtraction of background activity measured in the left ventricle cavity and dual-window scatter correction. Mismatching was expressed as a percentage of the surface of the left ventricle globally as well as for each arterial territory using a BMIPP uptake of at least 10% less than MIBI as the threshold. The results of dobutamine stress echocardiography and the evolution of the regional contractility at 6-mo follow-up were used as references. RESULTS: Mean background activity in the ventricle cavity was 9.3% of the maximum activity for MIBI and 21.4% for BMIPP before, and 2.8% and 8.3% after scatter correction. Fourteen arterial vascular territories demonstrated baseline wall-motion abnormalities; 9 territories showed contractile reserve with dobutamine stress echocardiography. Significant mismatching was found in 5 of 14 regions without correction, 9 of 14 after scatter correction and 13 of 14 after background subtraction. Compared with the evolution of resting regional contractility at follow-up, optimal results were found when using the scatter-corrected data. Without correction, mismatching between BMIPP and MIBI was partially disguised because of the higher noise level in the iodine images. On the contrary, subtraction of background measured by means of a single region of interest overestimated the magnitude of mismatching due to the heterogeneous background distribution in the ventricular cavity. CONCLUSION: In quantifying the presence and extent of mismatching between MIBI and BMIPP in chronic ischemic heart disease, significant differences in the detection of viability are noted according to the acquisition and processing methods used. Scatter correction of the acquisition data is the most accurate and reliable method for identifying viable myocardium.

Fatty Acids↗
PubMed1997

The temporal evolution of MRI tissue signatures after transient middle cerebral artery occlusion in rat.

We have developed a multiparameter magnetic resonance imaging (MRI) cluster analysis model of acute ischemic stroke using T2 relaxation times and the diffusion coefficient of water (ADCw). To test the ability of this model to predict cerebral infarction, male Wistar rats (n = 7) were subjected to 2 h of transient middle cerebral artery (MCA) occlusion, and diffusion and T2 weighted MRI were performed on these rats before, during and up to 7 days after MCA occlusion. MRI tissue signatures, specified by values of ADCw and T2 were assigned to tissue histopathology. Significant correlations were obtained between MRI signatures at different time points and histopathologic measurements of lesion area obtained at 1 week. In addition, we compared the temporal evolution of MRI tissue signatures to a separate population of animals at which histological data were obtained at select times of reperfusion. A significant shift (p < or = 0.05) within signatures reflecting tissue histopathology was demonstrated as the ischemic lesion evolved over time. Our data suggest, that the MRI signatures are associated with the degree of ischemic cell damage. Thus, the tissue signature model may provide a noninvasive means to monitor the evolution of ischemic cell damage and to predict final outcome of ischemic cell damage.

Animals↗
PubMed1995

Characterization of the lung cancer epidemic in the European Union (1970-1990).

To characterize the situation of the lung cancer epidemic in the former European Community countries, we analyzed mortality time trends between 1970 and 1990, and by using Poisson log-linear models, we compared patterns of evolution between Mediterranean and non-Mediterranean countries. To ascertain the course traced by the cohort effect and the inflection points marking shifts in trend in the epidemic, we made use of invariant parameters from age-period-cohort models (net drift, curvature) and restricted slope range for cohort effect. Regarding men, whereas non-Mediterranean countries had already initiated the downward phase of the process, the Mediterranean countries, with the single exception of Italy, proved to be entirely in the development stage. Women evinced a different pattern of evolution in regard to both rate magnitudes and trend behavior. Apart from Spain and Greece, a sharp rise in adjusted and specific rates was observed for all countries.

Adult↗
PubMedDate not supplied

[Ileoanal anastomosis with and without reservoir in children and adolescents with ulcerative rectocolitis and familial polyposis].

We compared the postoperative evolution of patients in whom an ileoanal anastomosis was performed, with (group 1, n:9) an without (group 2, n:7) an ileal reservoir. 3 of the 9 patients in group 1 developed intractable diarrhea, it was necessary to reoperate these children and to construct an ileal reservoir. It was not necessary to reoperate any of the group 2 patients; 2 of whom still have an ileostomy due to the presence of preanastomotic abscess. These 2 last patients where excluded from the following analysis. 2 months after surgery, children in group 1 had 16 +/- 2 bowel movements a day, compared with 8 +/- 2 in group 2, p less than 0.05. Children in group 1 did less well than those in group 2 when the following parameters were compared: fecal incontinence (7/9 vs 0/5), perianal dermatitis (6/9 vs. 1/5), treatment with antidiarrheal agents (5/9 vs 0/5), missing school (4/9 vs 0/5) and diminished social activities (4/9 vs 0/5). We conclude that in children who require colectomy, better results are obtained when an ileoanal anastomosis with ileal reservoir is performed.

Adenomatous Polyposis Coli↗
PubMedDate not supplied

[Diet therapy of enteritis in children (experience in 929 cases)].

929 cases of acute enteritis are reviewed. They were admitted since 1972 to 1981 in the first Pediatric Department of Modena, and treated with dietetic therapy. The periods of stool normalisation according the treatment received are discussed (oral rehydrating therapy versus casein hydrolysate). The results are compared with the evolution of diarrhea in 322 children treated with antidiarrheal adsorbents. According to our experience the diet with casein hydrolysate results to be an effective therapy of acute diarrhea, affording a nearly complete reduction in the use of intravenous infusions.

Acute Disease↗
PubMed2003

Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: enlarging genus Homo.

What do functionally important DNA sites, those scrutinized and shaped by natural selection, tell us about the place of humans in evolution? Here we compare approximately 90 kb of coding DNA nucleotide sequence from 97 human genes to their sequenced chimpanzee counterparts and to available sequenced gorilla, orangutan, and Old World monkey counterparts, and, on a more limited basis, to mouse. The nonsynonymous changes (functionally important), like synonymous changes (functionally much less important), show chimpanzees and humans to be most closely related, sharing 99.4% identity at nonsynonymous sites and 98.4% at synonymous sites. On a time scale, the coding DNA divergencies separate the human-chimpanzee clade from the gorilla clade at between 6 and 7 million years ago and place the most recent common ancestor of humans and chimpanzees at between 5 and 6 million years ago. The evolutionary rate of coding DNA in the catarrhine clade (Old World monkey and ape, including human) is much slower than in the lineage to mouse. Among the genes examined, 30 show evidence of positive selection during descent of catarrhines. Nonsynonymous substitutions by themselves, in this subset of positively selected genes, group humans and chimpanzees closest to each other and have chimpanzees diverge about as much from the common human-chimpanzee ancestor as humans do. This functional DNA evidence supports two previously offered taxonomic proposals: family Hominidae should include all extant apes; and genus Homo should include three extant species and two subgenera, Homo (Homo) sapiens (humankind), Homo (Pan) troglodytes (common chimpanzee), and Homo (Pan) paniscus (bonobo chimpanzee).

Animals↗
PubMed1998

A radiation hybrid map of BTA23: identification of a chromosomal rearrangement leading to separation of the cattle MHC class II subregions.

Bovine chromosome 23 (BTA23) contains the bovine major histocompatibility complex (MHC) and is thus of particular interest because of the role of MHC genes in immunity. Previous studies have shown cattle MHC class II genes to be subdivided into two distinct subregions separated by a variable genetic distance of 15-30 cM. To elucidate the genetic events that resulted in the present organization of the class II and other MHC genes, a framework radiation hybrid (RH) map of BTA23 was developed by testing DNA samples from a 5000 rad whole genome RH panel. Twenty-six markers were screened with an average retention frequency of 0.27, ranging from 0.14 to 0.42. Total length of the chromosome was 220 cR5000, with 4.1 cR5000/cM when compared to linkage data. Gene orders for the markers common to both the RH framework map and the consensus framework linkage map are identical. Large centiray intervals, D23S23-D23S7, DYA-D23S24 and CYP21-D23S31, were observed compared to linkage distances. These data may indicate a much larger physical distance or suppression of recombination in the interval separating the class II subregions and also within the class I region than previously estimated. Comparison of 13 Type I genes conserved between BTA23 and the human homolog HSA6p suggests the occurrence of an inversion encompassing the centromeric half of the bovine chromosome, thus explaining the large distance between the bovine class IIa and IIb clusters. These results exemplify the power of RH mapping in solving problems in comparative genomics and evolution. Furthermore, noncongruence of the genetic and physical RH map distances indicates that caution must be observed in using either resource alone in searching for candidate genes controlling traits of economic importance.

Animals↗
PubMed1988

Pharmacokinetics and renal accumulation of three iodinated contrast agents. A comparative study of Telebrix, Hexabrix and Omnipaque in the rabbit.

Male and female New Zealand rabbits were given a single bolus injection of 5 ml/kg of Telebrix, Hexabrix or Omnipaque intravenously. Animals were sacrificed 2, 8 and 24 h after the injection. One group of animals received a continuous i.v. infusion of contrast medium at a constant rate of 2.5 ml/kg/h for 4 h. Animals from this group were killed 30 min after the end of the infusion. Product clearance from plasma was studied in the animals given the i.v. bolus of contrast material and sacrified at 24 h postinjection. Plasma and tissue concentrations of contrast material were determined by high-performance liquid chromatography. Plasma elimination half-lives were identical in males and females and for all three products (approximately 45 min). The same held true for the volume of distribution which comprised between 20 and 26% of body weight. At 2 h postinjection, renal cortical concentrations of contrast medium were 8 to 10 times higher than plasma concentrations. For all three contrast agents, concentrations found in the renal cortex were higher than those in the medulla or the papilla at all observation times. As compared with the evolution of plasma concentrations over time, renal accumulation of the products was found to be persistent. The ionic or non-ionic nature of the tested products and their hydrophilic properties seem to play an essential role in the renal accumulation pattern.

Animals↗
PubMed1983

The chest X-ray in Legionella Pneumonia (Legionnaires' disease).

The authors compared the radiological evolution and patterns of Legionella pneumophila pneumonia in 13 immunocompromised and 13 non-immunocompromised patients. Apart from the occurrence of cavitation and the longer time it took before consolidations cleared in immunocompromised patients no differences were found between the two groups of patients.

Adult↗
PubMed2000

Effects of proton beam irradiation on uveal melanomas: a comparative study of Ki-67 expression in irradiated versus non-irradiated melanomas.

AIMS: To assess the cellular proliferation using the monoclonal antibody Ki-67, in paraffin embedded uveal melanomas irradiated by proton beam, as well as in non-irradiated uveal melanomas. METHODS: 30 enucleated eyes were included for histopathological study and Ki-67 immunostaining. Patients were enucleated between 1991 and 1996 for uveal melanoma, 14 after proton beam irradiation and 16 without treatment (control group). The mean follow up period was 2.5 years after diagnosis and 1 year after enucleation. RESULTS: A significant relation was found between Ki-67 score and mitotic index (r = 0.56, p = 0.001), histological largest tumour diameter (r = 0.38, p = 0. 03), fibrosis (r = -0.35, p = 0.05), absence of tumoral pigmentation (p = 0.05), and presence of vascular thrombosis (p = 0.03). The Ki-67 score was significantly higher in the non-irradiated group (p = 0.01) and in the group of patients whose cause of enucleation was tumoral evolution (p = 0.005) compared with the group of patients enucleated after neovascular glaucoma. The Ki-67 score was very high in a case of orbital recurrence of uveal melanoma and metastatic death. 70% of metastasised tumours showed a Ki-67 score higher than the median value. CONCLUSION: Ki-67 labelling is a reliable method of estimating the proliferative activity in uveal melanomas after proton beam irradiation. The Ki-67 score is significantly correlated with prognostic variables (mitotic index and histological largest tumour diameter), and with radiation effects after proton beam irradiation.

Adult↗
PubMed2003

Hexapod origins: monophyletic or paraphyletic?

Recent morphological and molecular evidence has changed interpretations of arthropod phylogeny and evolution. Here we compare complete mitochondrial genomes to show that Collembola, a wingless group traditionally considered as basal to all insects, appears instead to constitute a separate evolutionary lineage that branched much earlier than the separation of many crustaceans and insects and independently adapted to life on land. Therefore, the taxon Hexapoda, as commonly defined to include all six-legged arthropods, is not monophyletic.

Animals↗
PubMed1999

Do essential genes evolve slowly?

Approximately two thirds of all knockouts of individual mouse genes give rise to viable fertile mice. These genes have thus been termed 'non-essential' in contrast to 'essential' genes, the knockouts of which result in death or infertility. Although non-essential genes are likely to be under selection that favours sequence conservation [1], it is predicted that they are less subject to such stabilising selection than essential genes, and hence evolve faster [2]. We have addressed this issue by analysing the molecular evolution of 108 non-essential and 67 essential genes that have been sequenced in both mouse and rat. On preliminary analysis, the non-essential genes appeared to be faster evolving than the essential ones. We found, however, that the non-essential class contains a disproportionate number of immune-system genes that may be under directional selection (that is, selection favouring change) because of host-parasite coevolution. After correction for this bias, we found that the rate at which genes evolve does not correlate with the severity of the knockout phenotype. This was corroborated by the finding that, whereas neuron-specific genes have significantly lower rates of change than other genes, essential and non-essential neuronal genes have comparable rates of evolution. Our findings most probably reflect strong selection acting against even very subtle deleterious phenotypes, and indicate that the putative involvement of directional selection in host-parasite coevolution and gene expression within the nervous system explains much more of the variance in rates of gene evolution than does the knockout phenotype.

Algorithms↗
PubMed1976

Evolution of Drosophila mitochondrial DNAs. Comparison of denaturation maps.

In an approach to the functional anatomy of the mitochondrial genome and its evolution, we have compared buoyant densities, contour lengths, and denaturation maps in circular mitochondrial DNAs of the genus Drosophila. Mitochondrial DNAs from three representatives of the subgenus Drosophila (D. virilis, D. hydei, D. funebris) are similar in size (approx. 5 mum or 1 - 10(7) daltons) and buoyant density (approx. 1.685 g/ml), while in two members of the subgenus Sophophora (D. melanogaster, D. simulans), mitochondrial DNAs are longer (approx. 6 mum or 12.4 - 10(6) daltons) and have a lower buoyant density (approx. 1.681 g/ml). The latter mitochondrial DNAs also share one distinctly large early melting region, which in D. melanogaster is equivalent to 1.54 mum of native DNA. The corresponding (A + T)-rich region in D. virilis or D. hydei mitochondrial DNA is 1 mum shorter. Except for this region, denaturation maps of D. melanogaster and D. virilis mitochondrial DNAs are indistinguishable. The addition or deletion of a single block of (A + T)-rich sequences can fully account for the differences in buoyant density and size between the mitochondrial DNAs we have examined. In an appendix, we show that there is an equivalent discrepancy between the extent of strand separation determined by electron by electron microscopy and the actual extent of DNA denaturation, whether this is determined from absorbance changes or inferred from the reduction in contour lengths of individual circular molecules. The reduction in contour length appears to result exclusively from the uniform foreshortening of single-stranded DNA, not only in regions of visible strand separation but also in denatured regions hidden within putatively native segments of molecules. For molecules showing 15--45% strand separation, we estimate that putatively native segments are approximately 50% denatured.

Animals↗