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PubMed1989

Evaluation of change with time of glomerular morphology in membranoproliferative glomerulonephritis: a serial biopsy study of 33 cases.

The evolution of renal glomerular lesions was examined in biopsies taken from 33 patients with membranoproliferative glomerulonephritis (MPGN). 25 patients had a diffuse form of MPGN in the first biopsy (group A). Twenty-four of them still showed diffuse MPGN in subsequent biopsies, but one patient improved clinically and histologically 19 years after the initial biopsy. Out of 6 patients with focal MPGN in the first biopsy (group B), 4 developed diffuse MPGN, one remained with focal MPGN in the repeat biopsy, and another one was found in remission, as determined by both histological and clinical features. Group C represents two patients who had no histological findings of MPGN on initial biopsy but later showed evidence of a diffuse form of MPGN on subsequent biopsies. Thus, the focal form of MPGN may be found either in the development of diffuse MPGN or in its healing stage, and the prognosis will vary accordingly.

Adolescent↗
PubMed1984

Postnatal evolution of the rat pineal gland: light microscopy.

The postnatal development and morphology of the adult albino rat pineal gland was studied from one day up to ten months of age. During postnatal life there was a marked increase in gland and pinealocyte volume, more intense during the first 45 days. After ten days, the differences in nuclear morphology of parenchymal cells showed two different types of pinealocyte. The characteristic adult arrangement of pinealocytes in cords and pseudo-rosettes was observed after 15-20 days. After 75 days there was a progressive increase in the number of connective tissue fibres.

Aging↗
PubMed2006

Evidence for a microRNA expansion in the bilaterian ancestor.

Understanding how animal complexity has arisen and identifying the key genetic components of this process is a central goal of evolutionary developmental biology. The discovery of microRNAs (miRNAs) as key regulators of development has identified a new set of candidates for this role. microRNAs are small noncoding RNAs that regulate tissue-specific or temporal gene expression through base pairing with target mRNAs. The full extent of the evolutionary distribution of miRNAs is being revealed as more genomes are scrutinized. To explore the evolutionary origins of metazoan miRNAs, we searched the genomes of diverse animals occupying key phylogenetic positions for homologs of experimentally verified human, fly, and worm miRNAs. We identify 30 miRNAs conserved across bilaterians, almost double the previous estimate. We hypothesize that this larger than previously realized core set of miRNAs was already present in the ancestor of all Bilateria and likely had key roles in allowing the evolution of diverse specialist cell types, tissues, and complex morphology. In agreement with this hypothesis, we found only three, conserved miRNA families in the genome of the sea anemone Nematostella vectensis and no convincing family members in the genome of the demosponge Reniera sp. The dramatic expansion of the miRNA repertoire in bilaterians relative to sponges and cnidarians suggests that increased miRNA-mediated gene regulation accompanied the emergence of triploblastic organ-containing body plans.

Algorithms↗
PubMed2003

Viviparity as a constraint on sex-ratio evolution.

In polytocous mammals, the sex ratio during gestation can influence a variety of morphological, physiological, and life-history traits because of steroid leakage between fetuses. Similar phenomena have also recently been described for a viviparous lizard. Some of these effects have important fitness consequences by influencing reproductive success later in life. Thus, biasing the sex ratio toward one sex may lead to a decreased fitness for the other sex, and therefore constrain the evolution of skewed sex ratios. By incorporating effects of sex ratio on offspring fitness in a simple sex-allocation model, I show that, under some circumstances (1) skewed sex ratios are predicted to evolve, and (2) this cost can constrain the evolution of skewed sex ratios.

Animals↗
PubMed2003

The evolution of signalling pathways in animal development.

Despite the bewildering number of cell types and patterns found in the animal kingdom, only a few signalling pathways are required to generate them. Most cell-cell interactions during embryonic development involve the Hedgehog, Wnt, transforming growth factor-beta, receptor tyrosine kinase, Notch, JAK/STAT and nuclear hormone pathways. Looking at how these pathways evolved might provide insights into how a few signalling pathways can generate so much cellular and morphological diversity during the development of individual organisms and the evolution of animal body plans.

Animals↗
PubMedDate not supplied

[The life form concept and the use in the analysis of life cycle evolutionary strategies].

The life form is a generalized morphoecological characteristic of an animal giving an idea of the organism as a whole, its position and function and functional role in the ecosystem. This characteristic is inherent to a species or to a group of congeneric species (for applied goal it is better to use a genus, not species) considered in the framework of higher taxon (from family to type). The principal contradiction of life form concept is determined by the existence of ontogenetic stages and changes of life forms during the whole life of individual. It is usually assumed that the concept of life form should be applied only to the adult stage, thus ignoring the integral character of the life cycle as indivisible unit of selection, evolution and functioning in ecosystem. We propose that a morphologically specific ontogenetic of a given species should be used as an elementary lowest unit in the classification of life forms. Thus it can be considered as integrated internally structured morphoecological unit in time and multidimensional space of abiotic and biotic environmental factors. As an example we describe the types of reproductive strategies and classification of elementary (ontogenetic) life forms in cephalopods. We present characteristics of the life cycle of some typical cephalopod species inhabiting different biotopes and having different models of locomotion, feeding, reproduction and development.

Animals↗
PubMed2004

The genetics of maize evolution.

Maize and its closest wild relatives, the teosintes, differ strikingly in the morphology of their female inflorescences or ears. Despite their divergent morphologies, several studies indicate that some varieties of teosinte are cytologically indistinguishable from maize and capable of forming fully fertile hybrids with maize. Molecular analyses identified one form of teosinte (Zea mays ssp. parviglumis) as the progenitor of maize. Analyses of the inheritance of the morphological traits that distinguish maize and teosinte indicates that they are under the control of multiple genes and exhibit quantitative inheritance. Nevertheless, these analyses have also identified a few loci of large effect that appear to represent key innovations during maize domestication. Remaining challenges are to identify additional major and minor effect genes, the polymorphisms within these genes that control the phenotypes, and how the combination of the individual and epistatic effects of these genes transformed teosinte into maize.

Biological Evolution↗
PubMed2002

[Agenesis and the morphology and site of other teeth in the permanent dentition].

OBJECTIVE: To Investigate the relationship among anodontia, anomalously shaped teeth and reduction of teeth crown. METHODS: The position and the number of congenitally absent teeth of 79 patients were analysed, as well as the abnormal morphology of other teeth. The width of the remained teeth was measured and compared with that of normal on base of patients being divided into four groups by the number and the position of agenesis. RESULTS: (1)Most of the congenitally absent teeth were upper lateral incisors and lower central incisors. (2) The congenitally absent teeth of upper central incisors, upper and lower first molars were rare. While in several cases, the central incisors were lightly pet-shaped. (3) There was no significant difference in teeth size between mild hypodontia groups and normal. As the incremental degree of hypodontia, anterior teeth tended to reduce, while the size of posterior teeth was relatively stable. Upper lateral incisors, lower canines, upper second premolars, upper and lower second molars accounted most in the anomalously shaped teeth which could be often found in patients with hypodontia. CONCLUSION: (1) number during evolution. (2) The developmental anomaly of teeth size, teeth morphology and teeth number might be a procedure of continuous variation and it might be different manifestation of the same mechanism.

English Abstract↗
PubMedDate not supplied

[Etiopathogenesis of progressive systemic sclerosis].

Progressive systemic sclerosis (PSS) is a systemic disease of connective tissue involving the skin and internal organs characterized by fibrotic and degenerative changes. The disease is usually progressive, incurable and always leads to death. Several hypotheses about the etiopathogenesis of PSS exist which try to explain the cause of morphological changes of the connective tissue. The first theory advocates evolution of the primary lesion within the blood vessels, the second considers the primary event to be an abnormality of collagen metabolism manifested by fibrosis. The third postulates on an autoimmune basis for the disease, and the fourth is based on the disfunction of autonomic nervous system. All the theories are partly linked and represent the morphological, biochemical and immunological aspects of the pathogenesis of this disease.

Humans↗
PubMedDate not supplied

[Molecular bases of evolution].

The general notions of the theory of evolution are listed. The unity of the "engineering principles" of the living nature is emphasized. The generalists and specialists species are discussed. The estimation of their evolution rates must be different if it is expressed by the number of species or by the morphological changes. The principles of "protein engineering" of the organisms and the role of metals in protein evolution are discussed. It is suggested that in the presence of ions of transition metals and zinc the Fox's proteinoids can possess more specific forms of enzymatic activity. In the evolution of language the horizontal transfer plays a much more important role than in the biological evolution. However in this case also the initial basis of the language remains. The random drift is considered and it is shown that in concordance with the neutralist theory there are no grounds to replace the calculation of the rates of mutational changes per time unity by the calculation per generation. The molecular drive is the main source of the evolutionary novelties. The drive is connected with drift. The synonymic mutations and the mutations in non-functional DNA are evolutionary important. The future mathematical theory of evolution must be based on the theory of Markov's chains with the stochastic matrix changing along the chain and containing the set of the non-diagonal members equal to zero. The results obtained in the theory of ontogeny are presented. The evolution of species is the evolution of ontogenies, the formation of the molecular theory of evolution can be possible only on the basis of the molecular theory of ontogeny. The internal causes of extinction of species reduce the accumulation of neutral and pseudo-neutral mutations.

Animals↗
PubMed1979

Primate facial allometry and interpretations of australopithecine variation.

Pilbeam and Gould have discussed African Plio-Pleistocene hominid evolution in the context of allometry (size-dependent morphological change). These authors demonstrate that some general aspects of australopithecine morphology (tooth, brain and body size) support the hypothesis that certain early African hominids were merely scaled variations of each other at different sizes. They also speculate that the methods applied to these very broad anatomical categories can be extended to more specific and detailed traits, especially in the face and cranium. Such traits underlie most taxonomic and phylogenetic discussions of the early African Hominidae, so it is useful to follow Pilbeam and Gould's lead, as we do here, and investigate the structural differences in the australopithecine face and cranimum in a quantificiable fashion.

Africa↗
PubMedDate not supplied

[Duodenal post-bulbar ulcers. Diagnostic and therapeutic problems].

Our study upon 1235 cases of duodenal ulcers (1991 - 2001) revealed a decrease of its morbidity rate of 10 - 12%. However, the incidence of the post-bulbar duodenal ulcer (P.B.D.U.) remained constant - 9,33% (115 cases) from all duodenal ulcers. Its diagnostic and therapeutic difficulties, its peculiar etiology, pathogeny, topography and evolution are the consequence of the duodeno-bilio-pancreatic morphologic modifications, clinic polymorphism, radiologic indirect signs and difficult endoscopic localisation. Definitive diagnosis was set only intraoperatively. There are 2 forms of P.B.D.U.: proximal (D1 fixed) - 62,60% and distal (D2 above duodenal papilla) - 37,40%. Associated bilio-digestive lesions were encountered in 30 cases (26,08%). Due to its aggressive, endocrine-type etiology and pathogeny, evolution to severe complications and resistance to modern medical therapy, the PBDU should be of first surgical intent, considering a radical procedure whenever possible. Gastric 2/3 resection or truncal vagotomy with limited gastric resection were achieved in 90,43% of cases. We preferred the Bilroth II type anastomosis (65,20%) excluding the ulcerous lesion. Drainage of the duodenal stump was employed in 26% of cases. Specific postoperative morbidity of 12,17%, an early re-operations rate of 6,05% and postoperative mortality of 3,47% versus 2,05% for the duodenal ulcers, emphasize the severity of the P.B.D.U.

Duodenal Ulcer↗
PubMed2006

Staminal evolution in the genus Salvia (Lamiaceae): molecular phylogenetic evidence for multiple origins of the staminal lever.

BACKGROUND AND AIMS: The genus Salvia has traditionally included any member of the tribe Mentheae (Lamiaceae) with only two stamens and with each stamen expressing an elongate connective. The recent demonstration of the non-monophyly of the genus presents interesting implications for staminal evolution in the tribe Mentheae. In the context of a molecular phylogeny, the staminal morphology of the various lineages of Salvia and related genera is characterized and an evolutionary interpretation of staminal variation within the tribe Mentheae is presented. METHODS: Two molecular analyses are presented in order to investigate phylogenetic relationships in the tribe Mentheae and the genus Salvia. The first presents a tribal survey of the Mentheae and the second concentrates on Salvia and related genera. Schematic sketches are presented for the staminal morphology of each major lineage of Salvia and related genera. KEY RESULTS: These analyses suggest an independent origin of the staminal elongate connective on at least three different occasions within the tribe Mentheae, each time with a distinct morphology. Each independent origin of the lever mechanism shows a similar progression of staminal change from slight elongation of the connective tissue separating two fertile thecae to abortion of the posterior thecae and fusion of adjacent posterior thecae. A monophyletic lineage within the Mentheae is characterized consisting of the genera Lepechinia, Melissa, Salvia, Dorystaechas, Meriandra, Zhumeria, Perovskia and Rosmarinus. CONCLUSIONS: Based on these results the following are characterized: (1) the independent origin of the staminal lever mechanism on at least three different occasions in Salvia, (2) that Salvia is clearly polyphyletic, with five other genera intercalated within it, and (3) staminal evolution has proceeded in different ways in each of the three lineages of Salvia but has resulted in remarkably similar staminal morphologies.

Evolution, Molecular↗
PubMed1998

Gnathostomulida--an enigmatic metazoan phylum from both morphological and molecular perspectives.

On the basis of few and contentious morphological characters Gnathostomulids have been thought to be the sister-group of either the Platyhelminthes or the Syndermata (Rotifera + Acanthocephala). We provide a full 18S rDNA sequence for a species of Gnathostomula and attempt to resolve its position among the Metazoa, on the basis of molecular evidence. Sixty sequences, representing 30 nominal phyla and including new entoproct and gastrotrich sequences, were used to reconstruct phylogenies using maximum-parsimony, neighbor-joining, and minimum evolution models. We were unable to support either of the morphological hypotheses outright and, moreover, our data supported more strongly a third possible relationship with the gnathostomulids as a member of the Nematoda + Chaetognatha clade. Superficially, as active benthic, vermiform creatures with sclerotized cuticular jaws, they fit a predicted ancestral form of the Nematoda + Chaetognatha clade and, as such, would arguably be members of the Ecdysozoa. The molecular data at least call for a reevaluation of the morphological data and a denser sampling of the lesser phyla. Data from morphology and molecules act synergistically in estimating phylogeny; morphology alone provided limited phylogenetic signal and alternative phylogenetic hypotheses, whereas the molecular solution suggested an alternative topology which, when interpreted in the light of comparative anatomy, may suggest previously unconsidered possibilities.

Acanthocephala↗
PubMed1986

Follow-up of renal morphology and growth of 141 children operated for vesicoureteral reflux: a retrospective computerized study.

This study relates the postoperative evolution after ureterovesical reimplantation for vesicoureteral reflux (VUR) in 141 children who were ten years old or younger at the time of surgery. Renal growth and morphology were evaluated 2 and 5 years after surgery. We estimated renal growth by measuring the ratio of the bipolar parenchymal thickness to the total length of the kidney. We noticed that whatever the degree of reflux might have been, most of the kidneys partially or totally compensated for their growth failure. This growth resumption required many years to be completed. Surgical correction of VUR had favorable consequences on the radiologic aspect of pyelonephritic scars only on some of the kidneys: in these cases, the child's age appeared to be the only factor that had a statistical importance affecting the postoperative evolution of pyelonephritic scarring: the younger the children were at the time of surgery, the better the results obtained.

Age Factors↗
PubMed2006

Gene regulatory networks and the evolution of animal body plans.

Development of the animal body plan is controlled by large gene regulatory networks (GRNs), and hence evolution of body plans must depend upon change in the architecture of developmental GRNs. However, these networks are composed of diverse components that evolve at different rates and in different ways. Because of the hierarchical organization of developmental GRNs, some kinds of change affect terminal properties of the body plan such as occur in speciation, whereas others affect major aspects of body plan morphology. A notable feature of the paleontological record of animal evolution is the establishment by the Early "Cambrian of virtually all phylum-level body plans. We identify a class of GRN component, the kernels" of the network, which, because of their developmental role and their particular internal structure, are most impervious to change. Conservation of phyletic body plans may have been due to the retention since pre-Cambrian time of GRN kernels, which underlie development of major body parts.

Adaptation, Biological↗