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PubMed1996

Extra-acral calcifying aponeurotic fibroma: a distinctive case with 23-year follow-up.

Calcifying aponeurotic fibroma (CAF) is an unusual but well-characterized soft tissue neoplasm that typically involves the digits of children and frequently recurs locally. This report describes a case from the subcutis of the lumbosacral region. A 26-year-old man initially presented at age 3 and developed three recurrences over a 23-year period each at approximately 8-year intervals (ages 10, 18, and 26). The microscopic findings in all recurrences showed a lobulated, poorly circumscribed proliferation of dense fibrous tissue containing epithelioid-like fibroblasts, multinucleated cells, and islands of metaplastic chondroid differentiation with focal calcification. Despite origin from an unusual anatomic site, this case reported herein demonstrates the classical morphologic features and clinical history of CAF which showed little in the way of morphologic evolution despite 23 years of persistence. The clinical and histologic features helpful in distinguishing CAF from infantile fibromatosis and soft tissue chondroma are discussed.

Adult↗

PubMed1999

The root of angiosperm phylogeny inferred from duplicate phytochrome genes.

An analysis of duplicate phytochrome genes (PHYA and PHYC) is used to root the angiosperms, thereby avoiding the inclusion of highly diverged outgroup sequences. The results unambiguously place the root near Amborella (one species, New Caledonia) and resolve water lilies (Nymphaeales, approximately 70 species, cosmopolitan), followed by Austrobaileya (one species, Australia), as early branches. These findings bear directly on the interpretation of morphological evolution and diversification within angiosperms.

Apoproteins↗

PubMed1978

Frog perspective on the morphological difference between humans and chimpanzees.

The body shapes of humans and chimpanzees were compared quantitatively by criteria chosen for their capacity to discriminate well among the body shapes of frogs. By these criteria, the difference in body shape between humans and chimpanzees was found to be greater than that between the most dissimilar pairs of frogs examined--that is, frogs classified in separate taxonomic suborders. Even though the morphological diffference between the two primates is large by frog standards, the biochemical differences between the structural genes of these two species are small. The results of this study give quantitative support to the proposal that morphological evolution and biochemical evolution in structural genes can proceed at independent rates.

Animals↗

PubMed1989

Serological and histological follow up of chronic hepatitis B infection.

In order to study the clinical, serological, and morphological evolution of chronic hepatitis B virus infection in childhood, a prospective study has been carried out. A total of 90 children with a chronic infection were followed up for a mean (SD) of 3 (1.8) years. At the beginning of the study, 61 children were asymptomatic and 77 were household contacts of chronic carriers. Serologically 77 were hepatitis B e antigen (HBeAg) positive and 71 of them were positive to hepatitis B virus DNA. The mean alanine aminotransferase activities were higher among HBeAg positive patients than in antihepatitis B e (anti-HBe) positive ones. The most severe histological damage was also found among HBeAg positive patients. The annual seroconversion rate was 14%. A significant increase in the alanine aminotransferase activity was observed 13 (5.6) months before appearance of anti-HBe in the 85% of cases. Among anti-HBe positive patients, the alanine aminotransferase activities were normal in all except three (19%), two of whom had intrahepatic delta antigen. An increase in the histological activity was observed among patients who maintained HBeAg presence while an amelioration of liver damage was observed in anti-HBe carriers.

Adolescent↗

PubMed1994

PID, a new member of the P1 bacteriophage group.

Phage P1D produces particles of essentially uniform head size and differs from P1 in its range and tail length. The dimensions of phage P1 are reassessed. The P1 phage group shows signs of morphological evolution.

Bacteriophage P1↗

PubMed1995

Matching behavioral evolution to brain morphology.

A method is presented to test the relationship between a phylogenetic tree derived from brain morphology, and different hypotheses describing the evolution of a behavioral trait. This is a question of interest for evolutionary psychologists and behavioral biologists. The paper first discusses how hypotheses for behavioral evolution should be coded for such a comparison, then a triple-per-mutation test, originally proposed to compare independently obtained evolutionary trees, is used for the statistical assessment of each hypothesis. Non-parametric correlation coefficients computed between brain components and appropriately coded behavioral states can then be used to suggest what brain components are responsible for the development of the various states of the behavioral trait of interest. The procedure is illustrated with three different applications relating brain evolution to habitat selection in marsupials, locomotory specialization in primates, and trophic adaptation in bats.

Adaptation, Physiological↗

PubMed2003

Long-term follow-up of aortic intramural hematoma: predictors of outcome.

BACKGROUND: Aortic intramural hematoma (IMH) evolves very dynamically in the short-term to regression, dissection, or aortic rupture. The aim of the present study was to assess the long-term clinical and morphological evolution of medically treated IMH. METHODS AND RESULTS: Fifty of 68 consecutive patients with aortic IMH monitored clinically and by imaging techniques at 3, 6, and 12 months and annually thereafter were prospectively studied. Mean follow-up was 45+/-31 months. In the first 6 months, total IMH regression was observed in 14 and progression to aortic dissection in 18 patients; in 14 of these, the dissection was localized, and 12 later developed pseudoaneurysm. At the end of follow-up, the IMH had regressed completely without dilatation in 17 patients (34%), progressed to classical dissection in 6 (12%), evolved to fusiform aneurysm in 11 (22%), evolved to saccular aneurysm in 4 (8%), and evolved to pseudoaneurysm in 12 (24%). Evolution to dissection was related to echolucency (P<0.02) and to longitudinal extension of IMH (P<0.01). Multivariate analysis showed an independent association between regression and smaller maximum aortic diameter and between aneurysm formation and atherosclerotic ulcerated plaque and absence of echolucent areas in IMH. CONCLUSIONS: The most frequent long-term evolution of IMH is to aortic aneurysm or pseudoaneurysm. Complete regression without changes in aorta size is observed in one third of cases, and progression to classical dissection is less common. A normal aortic diameter in the acute phase is the best predictor of IMH regression without complications, and absence of echolucent areas and atherosclerotic ulcerated plaque are associated with evolution to aortic aneurysm.

Aortic Dissection↗

PubMed1991

An improved photochemical model of embolic cerebral infarction in rats.

To provide further evidence that the multiple cerebral infarcts found in rats following photochemical damage to the carotid artery are caused by emboli and to eliminate the systemic hypotension and heating of the blood reported with the previous photochemical embolic stroke model (rose bengal and a green laser), I have modified the photochemical technique. Brain pathology was studied in 18 Wistar rats following carotid artery irradiation with a red laser (632 nm) at powers ranging from 100 to 800 mW/cm2 for 10 or 20 minutes following the injection of the photosensitizing dye Photofrin II. Multiple cerebral arterioles were occluded by platelet aggregates containing frequent erythrocytes and leukocytes, identical to the thrombotic material in the carotid artery but different from the platelet aggregates seen in the carotid artery and the brain in the rose bengal model. Eighty infarcts were distributed randomly throughout the brain ipsilateral to the nonocclusive carotid thrombus. Significant heating (0.5 degree C or more) of the blood occurred only with laser powers higher (1,600 mW/cm2) or laser irradiations longer (25 minutes) than those used in the improved model of embolic stroke. This model mimics one mechanism of stroke in humans and provides a means to study systematically the morphological evolution of small cerebral infarcts.

Animals↗

PubMed2006

A wing expressed sequence tag resource for Bicyclus anynana butterflies, an evo-devo model.

BACKGROUND: Butterfly wing color patterns are a key model for integrating evolutionary developmental biology and the study of adaptive morphological evolution. Yet, despite the biological, economical and educational value of butterflies they are still relatively under-represented in terms of available genomic resources. Here, we describe an Expression Sequence Tag (EST) project for Bicyclus anynana that has identified the largest available collection to date of expressed genes for any butterfly. RESULTS: By targeting cDNAs from developing wings at the stages when pattern is specified, we biased gene discovery towards genes potentially involved in pattern formation. Assembly of 9,903 ESTs from a subtracted library allowed us to identify 4,251 genes of which 2,461 were annotated based on BLAST analyses against relevant gene collections. Gene prediction software identified 2,202 peptides, of which 215 longer than 100 amino acids had no homology to any known proteins and, thus, potentially represent novel or highly diverged butterfly genes. We combined gene and Single Nucleotide Polymorphism (SNP) identification by constructing cDNA libraries from pools of outbred individuals, and by sequencing clones from the 3' end to maximize alignment depth. Alignments of multi-member contigs allowed us to identify over 14,000 putative SNPs, with 316 genes having at least one high confidence double-hit SNP. We furthermore identified 320 microsatellites in transcribed genes that can potentially be used as genetic markers. CONCLUSION: Our project was designed to combine gene and sequence polymorphism discovery and has generated the largest gene collection available for any butterfly and many potential markers in expressed genes. These resources will be invaluable for exploring the potential of B. anynana in particular, and butterflies in general, as models in ecological, evolutionary, and developmental genetics.

Animals↗

PubMed2006

Patterns of MADS-box gene expression mark flower-type development in Gerbera hybrida (Asteraceae).

BACKGROUND: The inflorescence of the cut-flower crop Gerbera hybrida (Asteraceae) consists of two principal flower types, ray and disc, which form a tightly packed head, or capitulum. Despite great interest in plant morphological evolution and the tractability of the gerbera system, very little is known regarding genetic mechanisms involved in flower type specification. Here, we provide comparative staging of ray and disc flower development and microarray screening for differentially expressed genes, accomplished via microdissection of hundreds of coordinately developing flower primordia. RESULTS: Using a 9K gerbera cDNA microarray we identified a number of genes with putative specificity to individual flower types. Intrestingly, several of these encode homologs of MADS-box transcription factors otherwise known to regulate flower organ development. From these and previously obtained data, we hypothesize the functions and protein-protein interactions of several gerbera MADS-box factors. CONCLUSION: Our RNA expression results suggest that flower-type specific MADS protein complexes may play a central role in differential development of ray and disc flowers across the gerbera capitulum, and that some commonality is shared with known protein functions in floral organ determination. These findings support the intriguing conjecture that the gerbera flowering head is more than a mere floral analog at the level of gene regulation.

Asteraceae↗

PubMed2006

An expressed sequence tag (EST) library from developing fruits of an Hawaiian endemic mint (Stenogyne rugosa, Lamiaceae): characterization and microsatellite markers.

BACKGROUND: The endemic Hawaiian mints represent a major island radiation that likely originated from hybridization between two North American polyploid lineages. In contrast with the extensive morphological and ecological diversity among taxa, ribosomal DNA sequence variation has been found to be remarkably low. In the past few years, expressed sequence tag (EST) projects on plant species have generated a vast amount of publicly available sequence data that can be mined for simple sequence repeats (SSRs). However, these EST projects have largely focused on crop or otherwise economically important plants, and so far only few studies have been published on the use of intragenic SSRs in natural plant populations. We constructed an EST library from developing fleshy nutlets of Stenogyne rugosa principally to identify genetic markers for the Hawaiian endemic mints. RESULTS: The Stenogyne fruit EST library consisted of 628 unique transcripts derived from 942 high quality ESTs, with 68% of unigenes matching Arabidopsis genes. Relative frequencies of Gene Ontology functional categories were broadly representative of the Arabidopsis proteome. Many unigenes were identified as putative homologs of genes that are active during plant reproductive development. A comparison between unigenes from Stenogyne and tomato (both asterid angiosperms) revealed many homologs that may be relevant for fruit development. Among the 628 unigenes, a total of 44 potentially useful microsatellite loci were predicted. Several of these were successfully tested for cross-transferability to other Hawaiian mint species, and at least five of these demonstrated interesting patterns of polymorphism across a large sample of Hawaiian mints as well as close North American relatives in the genus Stachys. CONCLUSION: Analysis of this relatively small EST library illustrated a broad GO functional representation. Many unigenes could be annotated to involvement in reproductive development. Furthermore, first tests of microsatellite primer pairs have proven promising for the use of Stenogyne rugosa EST SSRs for evolutionary and phylogeographic studies of the Hawaiian endemic mints and their close relatives. Given that allelic repeat length variation in developmental genes of other organisms has been linked with morphological evolution, these SSRs may also prove useful for analyses of phenotypic differences among Hawaiian mints.

5' Untranslated Regions↗

PubMed2006

A physico-chemical survey of inland lakes and saline ponds: Christmas Island (Kiritimati) and Washington (Teraina) Islands, Republic of Kiribati.

The equatorial Pacific Ocean atoll islands of Kiritimati and Teraina encompass great physical, chemical and biological variability within extreme lacustrine environments. Surveys of lake chemistry and sediments revealed both intra- and inter-island variability. A survey of more than 100 lakes on Kiritimati found salinities from nearly fresh to 150 ppt with the highest values occurring within the isolated, inland portions of the island away from the influence of groundwater or extreme tides. Dissolved oxygen (DO) and pH values also showed considerable variability with a less regular spatial pattern, but were both generally inversely related to salinity. Series of lakes, progressively more isolated from marine communication, present a modern analog to the chemical and morphologic evolution of presently isolated basins. Sediments on both islands consist of interbedded red and green silt, possibly degraded bacterial mat, overlying white, mineralogenic silt precipitate. Variability may be indicative of shifts in climatological parameters such as the El Niño Southern Oscillation (ENSO) or the Pacific Intertropical Convergence Zone (ITCZ).

Journal Article↗

PubMed1996

Mechanisms of tongue protraction and narial closure in the marine toad Bufo marinus.

Electromyography, kinematic analysis, muscle stimulation and denervation techniques were used to investigate the muscular mechanisms of narial closure during breathing and of tongue protraction during prey capture in the marine toad Bufo marinus. Toads were video-taped during breathing and feeding under a variety of conditions: before surgery, after unilateral or bilateral denervation of the M. submentalis, and after unilateral or bilateral denervation of the Mm. genioglossus basalis and medialis. Deeply anesthetized toads were video-taped during stimulation of several cranial muscles, and electromyograms were recorded from the M. submentalis during feeding before and after its denervation. Bufo marinus differs from many other anurans in having a relatively long tongue that experiences large accelerations (> 31 g) during protraction. Tongue protraction occurs in two phases: an early phase during which the lingual tip moves upward and forward relative to the mandibular tip as the tongue shortens, and a later phase during which the lingual tip moves downward and forward relative to the mandibular tip as the tongue elongates under its own momentum. Relative to an external reference, the lingual tip follows a straight trajectory from mouth to prey, which depends critically upon precise coordination of tongue and jaw movements. The M. submentalis is necessary for normal tongue protraction during feeding. In contrast, the Mm. genioglossus basalis and medialis are necessary for forward movement of the tongue pad over the symphysis. In B. marinus, a simple anatomical change (elongation of the tongue) has functional consequences (inertial elongation) that profoundly affect the mechanisms of neuromuscular control. Though seldom studied, it seems likely that morphological evolution has had a profound influence on mechanisms of motor control in animals generally.

Animals↗

PubMed2005

The origin of subfunctions and modular gene regulation.

Evolutionary explanations for the origin of modularity in genetic and developmental pathways generally assume that modularity confers a selective advantage. However, our results suggest that even in the absence of any direct selective advantage, genotypic modularity may increase through the formation of new subfunctions under near-neutral processes. Two subfunctions may be formed from a single ancestral subfunction by the process of fission. Subfunction fission occurs when multiple functions under unified genetic control become subdivided into more restricted functions under independent genetic control. Provided that population size is sufficiently small, random genetic drift and mutation can conspire to produce changes in the number of subfunctions in the genome of a species without necessarily altering the phenotype. Extensive genotypic modularity may then accrue in a near-neutral fashion in permissive population-genetic environments, potentially opening novel pathways to morphological evolution. Many aspects of gene complexity in multicellular eukaryotes may have arisen passively as population size reductions accompanied increases in organism size, with the adaptive exploitation of such complexity occurring secondarily.

Biological Evolution↗

PubMed2001

Vestigial organs as opportunities for functional innovation: the example of the Penstemon staminode.

Vestigial organs arise commonly during morphological evolution, but they need not be destined for elimination. Instead, vestigial organs may facilitate functional innovation because their freedom from functional constraints allows them to assume novel roles that their functional progenitor could not perform. We illustrate this vestigial transition between functions with an experimental study of the staminode of Penstemon flowers. Previous phylogenetic and developmental studies indicate that this staminode represents a stamen that was lost phenotypically, but not genetically, and then reappeared in the tribe Cheloneae, to which Penstemon belongs. To assess whether the Penstemon staminode has adopted a novel function(s), we compared pollination of flowers with and without staminodes for two bee-pollinated species, P. ellipticus and P. palmeri, and two hummingbird-pollinated species, P. centranthifolius and P. rostriflorus. The staminode acts differently in the two bee-pollinated species. For P. ellipticus, which represents the basal Penstemon lineage, the staminode hinders pollinator access to nectar, which increases visit duration and pollinator contact with sexual organs, thereby increasing pollen receipt by stigmas and controlling pollen removal from anthers. In contrast, in P. palmeri, the staminode acts as a lever that enhances stigma contact with the pollinator, so that staminode removal reduced pollen receipt, but did not affect pollinator attraction, visit duration, or pollen removal. Unlike in bee-pollinated species. staminode removal from hummingbird-pollinated species did not affect any measured aspect of pollination, indicating that the staminode serves no function in this derived pollination system. These results illustrate several features of vestigial organs: loss of function can be temporary; loss of function facilitates the evolution of novel roles; and functional reinvention will often involve only a single role, thus increasing the chance of both secondary loss of function (bird-pollinated penstemons) and functional switches (P. palmeri).

Animals↗

PubMedDate not supplied

New species of Septobasidium from southern Costa Rica and the southeastern United States.

New species are described in Septobasidium, a genus of urediniomycete parasites on scale insects. One new species, S. gomezii, is described from Costa Rica, and another, S. meredithiae, is described from Louisiana. S. gomezii is most similar to S. septobasidioides, but macroscopic and microscopic differences support it being a distinct species. S. meredithiae is similar to S. alni and S. castaneum but differs from these species in several macroscopic and microscopic characters, especially when the species are observed on the same host tree and insect species. Another species collected only once in Costa Rica is listed with observations but it is not formally described here. This Septobasidium species shares some key characteristics with S. ramorum but combines a dense, compact, nearly black thallus and pigmented probasidia-like structures with spindle-shaped haustoria. Implications for taxonomy, morphological evolution and host specificity in Septobasidium are discussed.

Animals↗

PubMed1999

Mechanisms of biliary carcinogenesis: a pathogenetic multi-stage cascade towards cholangiocarcinoma.

Carcinomas of the biliary tract are rare cancers developing from the epithelial or blast-like cells lining the bile ducts. A variety of known predisposing factors and recent experimental models of biliary carcinogenesis (e.g., infection with the liver fluke Opisthorchis viverrini, models of chemically induced carcinogenesis and experimental models of pancreaticobiliary maljunction) have elucidated different stages of this complex system of biliary tumorigenesis. Chronic inflammatory processes, generation of active oxygen radicals, altered cellular detoxification mechanisms, activation of oncogenes, functional loss of tumor-suppressor genes and dysregulation of cell proliferation and cell apoptotic mechanisms have been identified as important contributors in the development of cholangiocarcinomas. In this review, the known mechanisms involved in the carcinogenesis of biliary epithelium are addressed. We will divide the topic into four stages: 1) Predisposition and risk factors of biliary cancer. 2) Genotoxic events and alterations leading to specific DNA damage and mutation patterns. 3) Dysregulation of DNA repair mechanisms and apoptosis, permitting survival of mutated cells and 4) Morphological evolution from premalignant biliary lesions to cholangiocarcinoma. Finally, established and hypothetical future therapeutic strategies directed towards specific pathogenetic events during biliary carcinogenesis will be addressed.

Apoptosis↗

PubMedDate not supplied

The Hox-gene research programme and the shortcomings of molecular preformationism.

The study of the so-called HOM/Hox genes has provided many important insights on the control, at the molecular level, of developmental processes in a variety of model systems such as the fly and the mouse. Yet, in the specialised literature on the subject abound the claims that such genes, and the products coded by them, are the true morphogens responsible for determining the actual form of a particular organism. According to this view, morphogenesis results from the expression of specific 'master control' genes and thus, organic form is somehow pre-established (i.e., preformed) as an assembly programme encoded within the genome. Or in other words, it is claimed that the complex spatio-temporal order that leads to the achievement and maintenance of organic form is implied in a two-dimensional organisation of the genome. Moreover, some authors have claimed that the success of the Hox-gene research programme strongly suggests that morphological evolution is a direct result of evolution at the genetic level. Hereunder I discuss recent evidence that falsifies the basic preformationist tenets of molecular developmental biology. Thus suggesting that the problem of the origin of organic form is left untouched by the Hox-gene research programme and therefore, there is a need to reconsider alternative approaches, such as the structuralist morphogenetic outlook, that are better suited to eventually explain the origin of organic form.

Animals↗