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The authors report striking CT scan findings in a young woman with unilateral Moyamoya disease. Serial CT scans showed features that paralleled the clinical and pathophysiologic evolution of the disorder, in much the same way as has been reported in studies using serial angiograms.
The phylogenetic trees have been constructed for the mitochondrial ND5 gene sequences from the Japanese Leptocarabus ground beetles, which contain 101 specimens collected from nearly the complete distribution ranges of them consisting of five morphological species, i.e., Leptocarabus procerulus, L. kumagaii, L. hiurai, L. kyushuensis and L. arboreus. On the trees, there are recognized two major lineages, each of which is further divided into two or more sublineages. The phylogenetic lines are geographically linked. Two or more species occur in a single lineage, and the same species appear in different lines. We suggest that transformation from one type of morphology to another took place in parallel in various periods of evolution of the Japanese Leptocarabus. From the phylogenetic tree and the dating from the nucleotide substitution rate and the geohistorical data it is inferred that the ancestry of all the Japanese Leptocarabus species was derived from a protoform of L. kyushuensis inhabited the ancient Japan area, followed by separation into two lineages after split of the Japanese Islands from the Eurasian Continent. They then propagated distribution to occupy their own habitat ranges, during which the morphological transformation took place in some lineages.
OBJECTIVE: To discuss both early and recent ultrasound technologic advances and to explore the role of such technology in the evaluation of the thyroid gland. METHODS: The physics of sound and the history of the use of reflected sound waves are reviewed, and the medical applications of ultrasound, with a particular focus on the thyroid gland, are presented. RESULTS: Since the first reports of thyroid ultrasonography were published in the late 1960s, the field has undergone remarkable evolution. Ultrasound imaging improved in parallel with growth in computing, transducer, and display technology. The transition from A-mode to B-mode to gray-scale imaging was associated with dramatic improvements in clarity and interpretability of ultrasound images. Current high-resolution ultrasound images are able to identify virtually all structural thyroid lesions of clinical significance. Although ultrasound characteristics cannot be used for accurate diagnosis of benign thyroid lesions, certain features such as irregular margins, microcalcifications, and central vascularity suggest the presence of "suspicious" thyroid nodules. Recent advances including the use of contrast agents, tissue harmonic imaging, and multiplanar reconstruction of images will further enhance the resolution and interpretability of ultrasound images. The use of Doppler flow analysis may improve the predictive value for determining the risk of a malignant thyroid lesion, but no current ultrasound technique is capable of determining benignity with an acceptable degree of accuracy. Ultrasound guidance of fine-needle aspiration biopsy has been demonstrated to improve both diagnostic yield and accuracy and will likely become the standard of care. CONCLUSION: Because high-quality ultrasound systems are now available at a reasonable price, routine clinical use of ultrasonography is considered an important extension of the physical examination by many endocrinologists.
OBJECTIVE: To report the results of seric neuron specific enolase in pediatric neuroblastoma. PATIENTS AND METHODS: Our retrospective study concerns 21 children treated in our institution from 1992 to 1998 for neuroblastoma. Seric NSE was determined by immunoenzymology technique at different stages of the disease and the treatment. RESULTS: Mean value for the 39 dosages of the whole patients was 127.9 ng/ml with a sensitivity of 56%, five patients has presented normal values. Mean value for the 18 patients in stage IV was 132.38 ng/ml. We also observed in 3 patients, an evolution of the seric NSE parallel to this of the disease under chemotherapy. CONCLUSION: NSE represents a moderate sensitive and specific tumor marker for pediatric neuroblastoma. However, it represents a good value in prognosis and follow-up after chemotherapy.
The clinical toxicology plays a great part to the progresses of human therapy. It is an essential observation for a good clinical use of drugs and of materials used by physicians. It permits a better knowledge of the dose-effect relationship (in acute either in chronic adverse effects). It specifies the statement of the therapeutic efficacy between the threshold, a placebo effect with adverse disorders as those possibly related to any xenobiotic and the overdose where the nocivity predominates on the therapeutic results. A better detection of some individual responses as adverse or toxic reactions due to a genetic peculiarity belongs to clinical toxicogenetic studies in parallel with pharmacogenetics. The recent evolution of drugs needs a more scientific approach of the therapy for cytotoxic drugs largely used against cancers, in terms of tolerable doses, cumulative actions, interactions and cofactors. On the opposite, the bio-chemical variations of new bio-drugs acting as real bioprotheses of hormones or biomediators need specific toxicological studies according to the progresses and to the limits of biotechnologies. Among numerous drugs issued of chemical research one must separate the reversible functional drugs designed as enzyme-inhibitors or cellular receptors ligands very close to the dominant themes of biochemistry and experimental physiology from chemicals coined by synthetic "chance" which are for the time being plain xenobiotics whose dangers are often poorly evaluated but whose practical applications will take place either in disciplines related to pharmacopea like chemicals used in plant protection, either beginning their commercial trip very far from health concern in industrial preparations and being brought back to medicine as plastics, glues or metallic implants.(ABSTRACT TRUNCATED AT 250 WORDS)
Paleontologic and zoogeographic data speak in favour of Mesozoic origin of ixodid ticks. The absence of strict restrictions for the feeding on unusual species of hosts has caused the domination of polyphagy and oligophagy over monophagy among ixodid ticks. The same peculiarities of ixodid ecology are responsible for a restricted part or absence of phylogenetic parallelism with hosts in their evolution. Primary food relations with reptiles are, apparently, preserved only in the genus Aponomma and in many species of Amblyomma while hosts for most species of other genera are mammals and, to a lesser extent, birds. The number of potential hosts in these species can be much greater than that of real ones. Restrictions in the distribution of some species are connected rather with direct effect of unfavourable environmental factors on their nonparasitic stages of the life cycle than with the absence of suitable hosts. During the evolution of natural landscapes and at a shorter stages under the influence of successions or anthropogenic factors ixodids easily adapt themselves to feeding on new species of hosts. So the differentiation of primary and secondary hosts of these parasites is rather difficult.
Three strategies of different quality contribute in parallel to the natural formation of genetic variants in bacteria: (1) small local alterations of DNA sequences; (2) recombinational reshuffling of segments of the genome; and (3) acquisition of DNA sequences by horizontal gene transfer. Key enzymes involved in these processes often act as variation generators by making use of structural flexibilities of biological macromolecules and of the effect of random encounter. In the theory of molecular evolution, genetic determinants of variation generators as well as of modulators of the frequency of genetic variation are defined as evolutionary genes. This postulate is consistent with the notion that spontaneous mutagenesis is in general not adaptive and that the direction of evolution depends on natural selection exerted on populations of genetic variants.
Philosophers of biology have long argued that Darwin's theory of evolution was qualitatively different from all earlier theories of evolution. Whereas Darwin's predecessors and contemporaries explained adaptation as the transformation of a species' "essence," Darwin explained adaptation as the selective propagation of randomly occurring mutations within a population. The present study explored the possibility of a parallel between early "transformational" theories of evolution and modern naïve theories. Forty-two high school and college students and three evolutionary biologists were tested on their understanding of six evolutionary phenomena: variation, inheritance, adaptation, domestication, speciation, and extinction. As predicted, a plurality of participants demonstrated transformational reasoning inconsistent with natural selection. Correlational analyses revealed that participants who demonstrated transformational reasoning were as internally consistent as participants who demonstrated an understanding of natural selection, with the exception of one group of participants who appeared to have assimilated two heuristics--"survival of the fittest" and "acquired traits are not inherited"--into an otherwise transformational framework. These findings suggest that the widespread and early-developing tendency to essentialize biological kinds precludes students from conceptualizing species as populations of individuals differentially affected by the environment.
Prochlorophytes are prokaryotes that carry out oxygenic photosynthesis using chlorophylls a and b, but lack phycobiliproteins as light-harvesting pigments. These characteristics distinguish them from cyanobacteria, which contain phycobiliproteins, but no chlorophyll b. Three prochlorophyte genera have been described: Prochloron, Prochlorothrix and Prochlorococcus. The prochlorophytes share their pigment characteristics with green plant and euglenoid chloroplasts, which has led to a debate on whether these chloroplasts may have arisen from an endosymbiotic prochlorophyte rather than a cyanobacterium. Molecular sequence data, including those presented here based on a fragment of the rpoC1 gene encoding a subunit of DNA-dependent RNA polymerase, indicate that the known prochlorophyte lineages do not include the direct ancestor of chloroplasts. We also show that the prochlorophytes are a highly diverged polyphyletic group. Thus the use of chlorophyll b as a light-harvesting pigment has developed independently several times in evolution. Similar conclusions have been reached in parallel studies using 16S ribosomal RNA sequences.
Growth hormone levels rise steadily through normal puberty, in parallel with the pubertal stages but decline rapidly at the end of puberty (stage V). The general evolution of the secretory profile of GH is parallel to the growth velocity curve. The frequency of GH pulses remains unchanged; however, their amplitude, mean integrated concentrations, area under the curve, and urinary growth hormone are elevated at midpuberty. The main action of GH is to ensure, together with sex steroids, the pubertal growth spurt. However, the role of pubertal GH is not confined to inducing the pubertal growth spurt. It also participates, together with sex steroids, in the acquisition of adult bone mineral density.
The design of a strategy for the control of large scale cultures of hybridoma cells requires the use of convenient indicators to monitor properly the evolution of the biomass. In order to select appropriate indicators, we have measured in parallel, in bulk cultures of mouse hybridoma cells, the evolution of several metabolic parameters together with those of cell density and viability. We observed that flow cytometry analysis gives an early indication of the proliferative capacity of the cell population. Determination of metabolic rates (i.e. glucose, glutamine, amino acid, consumption, lactic acid or ammonium production) adequately indicates the current metabolic status of the cells. Indeed, a sharp decrease in these metabolic rates occurs rapidly following nutrient deficiency. Finally, measurements of lactate dehydrogenase (LDH) and DNA fragments released into the culture supernatants accurately reflect the kinetics of cell death.
The conception of the pathogenesis of a disease is probably as important in determining the selection of therapies as is the evidence provided by outcome studies of their efficacy. The recent evolution in our understanding of the pathogenesis of asthma has nicely paralleled advances in clinical research on new forms of treatment. This evolution has occurred so smoothly that we may not be fully aware how far it has taken us. Airflow obstruction is still regarded as the fundamental cause of the characteristic asthmatic symptoms of shortness of breath, chest tightness, and wheezing, while the factors leading to airflow obstruction are still assumed to include spasm of airway smooth muscle, thickening of the airway wall, and inspissation of viscid plugs of mucus in the airway lumen. What is new is the recognition of asthma as a chronic disease of the lower airways associated with characteristic inflammatory changes (involving lymphocytes, mast cells, and eosinophils), and possibly irreversible "remodeling" of the airways (by deposition of collagen and proteoglycans, proliferation and transformation of resident cells, and infiltration with inflammatory cells). This modern conception of asthma differs dramatically from the former perception of the disease as an episodic illness characterized by disturbance of the contractile function of airway smooth muscle. The new interpretation has important implications not just for the development of future therapies based on the inflammatory mechanisms involved in the pathogenesis of asthma, but also for the ways in which current therapies should be used.
Protein interactions are central to most biological processes. We investigated the dynamics of emergence of the protein interaction network of Saccharomyces cerevisiae by mapping origins of proteins on an evolutionary tree. We demonstrate that evolutionary periods are characterized by distinct connectivity levels of the emerging proteins. We found that the most-connected group of proteins dates to the eukaryotic radiation, and the more ancient group of pre-eukaryotic proteins is less connected. We show that functional classes have different average connectivity levels and that the time of emergence of these functional classes parallels the observed connectivity variation in evolution. We take these findings as evidence that the evolution of function might be the reason for the differences in connectivity throughout evolutionary time. We propose that the understanding of the mechanisms that generate the scale-free protein interaction network, and possibly other biological networks, requires consideration of protein function.
The fruiting bodies of homobasidiomycetes include some of the most complex forms that have evolved in the fungi, such as gilled mushrooms, bracket fungi and puffballs ('pileate-erect') forms. Homobasidiomycetes also include relatively simple crust-like 'resupinate' forms, however, which account for ca. 13-15% of the described species in the group. Resupinate homobasidiomycetes have been interpreted either as a paraphyletic grade of plesiomorphic forms or a polyphyletic assemblage of reduced forms. The former view suggests that morphological evolution in homobasidiomycetes has been marked by independent elaboration in many clades, whereas the latter view suggests that parallel simplification has been a common mode of evolution. To infer patterns of morphological evolution in homobasidiomycetes, we constructed phylogenetic trees from a dataset of 481 species and performed ancestral state reconstruction (ASR) using parsimony and maximum likelihood (ML) methods. ASR with both parsimony and ML implies that the ancestor of the homobasidiomycetes was resupinate, and that there have been multiple gains and losses of complex forms in the homobasidiomycetes. We also used ML to address whether there is an asymmetry in the rate of transformations between simple and complex forms. Models of morphological evolution inferred with ML indicate that the rate of transformations from simple to complex forms is about three to six times greater than the rate of transformations in the reverse direction. A null model of morphological evolution, in which there is no asymmetry in transformation rates, was rejected. These results suggest that there is a 'driven' trend towards the evolution of complex forms in homobasidiomycetes.
Six infants with cerebral infarcts were examined prospectively with real-time sonography to determine the sonographic characteristics of infarcts and their evolution. Patients' ages ranged from 1 day to 7 months, and serial sonographic and/or CT scans were obtained over a period of 2 weeks to 14 months in the survivors. Among our patients the most characteristic sonographic findings of infarction were absence of gyral definition, absence of vascular pulsations, altered parenchymal echogenicity, and territorial distribution. Mass effect, reflected in ventricular size and shift of midline structures, may also be seen and largely parallels the extent of the infarction. Evolution of infarcts was seen sonographically as gradual return of arterial pulsations and concurrent development of cystic spaces. Sonography was found to be a valuable tool in the diagnosis of infarction in infancy and in monitoring its evolution, although CT was necessary for adequate initial evaluation in older infants.
A requisite for efficacious host defense against pathogens and predators has prioritized evolution of effector molecules thereof. A recent multidimensional analysis of physicochemical properties revealed a novel, unifying structural signature among virtually all classes of cysteine-containing antimicrobial peptides. This motif, termed the gamma-core, is seen in host defense peptides from organisms spanning more than 2.6 billion years of evolution. Interestingly, many toxins possess the gamma-core signature, consistent with discoveries of their direct antimicrobial activity. Many microbicidal chemokines (kinocidins) likewise contain iterations of the gamma-core motif, reconciling their antimicrobial efficacy. Importantly, these polypeptide classes have evolved to target and modulate biomembranes in protecting respective hosts against unfavorable interactions with potential pathogens or predators. Extending on this concept, the current report addresses the hypothesis that antimicrobial peptides, kinocidins, and polypeptide toxins are structurally congruent and share a remarkably close phylogenetic relationship, paralleling their roles in host-pathogen relationships. Analyses of their mature amino acid sequences demonstrated that cysteine-stabilized antimicrobial peptides, kinocidins, and toxins share ancient evolutionary relatedness stemming from early precursors of the gamma-core signature. Moreover, comparative 3-D structure analysis revealed recurring iterations of antimicrobial peptide gamma-core motifs within kinocidins and toxins. However, despite such congruence in gamma-core motifs, the kinocidins diverged in overall homology from microbicidal peptides or toxins. These findings are consistent with observations that chemokines are not toxic to mammalian cells, in contrast to many antimicrobial peptides and toxins. Thus, specific functions of these molecular effectors may be governed by specific configurations of structural modules associated with a common gamma-core motif. These concepts are consistent with the hypothesis that the gamma-core is an archetype determinant in polypeptides that target or regulate with biological membranes, with specific iterations optimized to unique or cognate host defense contexts. Quantitative and qualitative data suggest these protein families emerged through both parallel and divergent processes of modular evolution. Taken together, the current and prior findings imply that the gamma-core motif contributes to conserved structures and functions of host defense polypeptides. The presence of this unifying molecular signature in otherwise diverse categories of membrane-active host defense peptides implies an ancient and essential role for such a motif in effector molecules governing host-pathogen relationships.
The authors trace the evolution of conditions of EEG recording parallel to the clinical criteria of certainty of the diagnosis of brain death, since the first definition of irreversible coma given by M. Goulon and P. Mollaret in 1959. They notice that over the past 30 years, the duration of the EEG has been reduced, their frequency decreased, and the delay between the clinical diagnosis of brain death with flat EEG and the switching off of the cardio-respiratory ventilation have been reduced from 48 to 6 h, thus enabling extremely early removal of organs; the slow progress of this evolution is explained by the difficulty over the years in distinguishing between brain death and certain reversible pathological conditions which resemble it, and by the fact that some EEGs may take some time to become flat. Actually, once these special cases have been eliminated, after the clinical diagnosis of brain death has been ascertained, we observe that two flat EEGs at an interval of 6 h are never subsequently modified. Finally, the EEG, a non-invasive method, seems always to be the quickest and the easiest method to carry out and especially to repeat, without any particular problem of staff or of place and is, thus, a reliable testimony in the event of medico-legal controversy.
One major parvalbumin each was isolated from the skeletal muscle of two reptiles, a boa snake, Boa constrictor, and a map turtle, Graptemys geographica, while two parvalbumins were isolated from an amphibian, the salamander Amphiuma means. The amino acid sequences of all four parvalbumins were determined from the sequences of their tryptic peptides, which were ordered partially by homology to other parvalbumins. Phylogenetic study of these and 16 other parvalbumin sequences revealed that the turtle parvalbumin belongs to beta lineage, while the salamander sequences belong, one each, to the alpha and beta lineages defined by Goodman and Pechère (1977). Boa parvalbumin, however, while belonging to the beta lineage, clusters within the fish in all reasonably parsimonious trees. The most parsimonious trees show many parallel or back mutations in the evolution of many parvalbumin residues, although the residues responsible for Ca2+ binding are very well conserved. These most parsimonious trees show an actinopterygian rather than a crossoptyrigian origin of the tetrapods in both the alpha and beta groups. One of two electric eel parvalbumins is evolving more than 10 times faster than its paralogous partner, suggesting it may be on its way to becoming a pseudogene. It is concluded that varying rates of amino acid replacement, much homoplasy, considerable gene duplication, plus complicated lineages make the set of parvalbumin sequences unsuitable for systematic study of the origin of the tetrapods and other higher-taxa divergence, although it may be suitable within a genus or family.