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PubMed2004

Neck fracture femoral heads for impaction bone grafting: evolution of stiffness and compactness during impaction of osteoarthrotic and neck-fracture femoral heads.

BACKGROUND: The need for safe bone allografts is increasing and preservation of femoral heads from patients being operated on with hip arthroplasty should be encouraged. However, should we preserve femoral heads from patients operated on for neck fracture as tissue mechanical quality may not be satisfactory? MATERIAL AND METHODS: We compared the evolution of stiffness and compactness of fresh-frozen morselized bone obtained from osteoarthrotic femoral heads and those from neck fractures. Both materials were also compared after freeze-drying and irradiation. We used 6 osteoarthrotic and 6 neck-fracture femoral heads to prepare 4 batches of morselized bone. 18 samples from each batch were impacted in a contained cylinder. Frozen bone grafts were tested after thawing at room temperature for 2 hours and freeze-dried grafts were tested after 30 minutes of rehydration. RESULTS: The stiffness of fresh-frozen neck fracture bone was lower than that of fresh-frozen osteoarthrotic bone at 150 impactions. The stiffness of freeze-dried irradiated bone was higher than that of the fresh-frozen bone and did not differ between osteoarthrotic and neck-fracture bone. INTERPRETATION: Solvent-treated freeze-dried bone from femoral heads procured during arthroplasty for sub-capital hip fractures represents a valuable source of material for allografts, addressing concerns regarding serological testing, medical history and bone quality.

Aged↗
PubMed2004

Comparative genomic analysis, diversity and evolution of two KIR haplotypes A and B.

Members of the killer immunoglobulin (Ig)-like receptor (KIR) gene family are tightly clustered on human chromosome 19q13.4. Despite considerable variation in KIR gene content and allelic polymorphism, most KIR haplotypes belong to one of two broad groups termed A and B. The availability of contiguous genomic sequences for these haplotypes has allowed us to compare their genomic organization, nucleotide (nt) diversity and reconstruct their evolutionary history. The haplotypes have a framework of three conserved blocks containing (i) KIR3DL3, (ii) KIR3DP1, 2DL4, and (iii) KIR3DL2 that are interrupted by two variable segments that differ in the number and type of KIR genes. Low (0.05%) nucleotide diversity was detected across the centromeric and telomeric boundaries of the KIR gene cluster while higher SNP density (0.2%) occurred within the central region containing the KIR2DL4 gene. Phylogenetic and genomic analyses have permitted the reconstruction of a hypothetical ancestral haplotype that has revealed common groupings and differences between the KIR genes of the two haplotypes. The present phylogenetic and genomic comparison of the two sequenced KIR haplotypes provides a framework for a more thorough examination of KIR haplotype variations, diversity and evolution in human populations and between humans and non-human primates.

Animals↗
PubMed1988

Influenza vaccination in the elderly: improved antibody response with Imuthiol (Na diethyldithiocarbamate) adjuvant therapy.

To improve influenza vaccine efficacy in hospitalized elderly, we compared the evolution of antibody level after vaccination in three patient groups. A sample of apparently primo vaccinated elderly were randomized to receive either Imuthiol (Na diethyldithiocarbamate: group 1) or a placebo (group P). They were compared to patients who had been vaccinated annually for several years (group C). All patients were immunized in the same week. Antibody responses increase within 15 days to reach a plateau in group P and C, while they continue to increase in the Imuthiol treated group, reaching higher antibody levels 30 days after vaccination. This higher antibody rise in group I is essentially due to higher antibody responses in patients with initially low antibody levels and who exhibited at least a four-fold antibody rise. This effect of Imuthiol on influenza antibody responses was observed in spite of a lower nutritional status in this group, a condition that induces lower antibody responses. The higher antibody responses observed in the Imuthiol treated group allow longer protection against influenza.

Adjuvants, Immunologic↗
PubMed1987

Red nucleus lesions delay the evolution of amygdala kindling in cats.

There are some papers which claim that the red nucleus (RN) is related to epileptic manifestations. Though the lesion or electrographic recording of the RN include many paths which assemble into it, the possibility that its cells are implicated in epilepsy is deduced. This paper compares the evolution of amygdaloid kindling in cats with bilateral RN lesions, with the epileptic disturbances provoked by lesion or stimulation of approach cells. Due to the intrinsic error of the stereotaxic method, only 7 of 13 cats show lesions in the RN with a diameter extending down to 150 micron. Only these show a shortening of the afterdischarge duration, a delay in the appearance of the consecutive clinical stages, and a lengthening in the appearance of generalized tonic-clonic seizures. In comparison, the 6 other cats show lesions mainly in the adjacent central tegmental field, and their kindling evolution was similar to that of a control group with intact mesencephalon. We conclude that the RN lesions interfere with the kindling generation, presumably by lesioning the cerebello-cerebral paths which produce a depression of cortical activity, during the consolidation of clinical and electrographic manifestations.

Amygdala↗
PubMed2004

Divergence in gene expression related to variation in host specificity of an ectomycorrhizal fungus.

Ectomycorrhizae are formed by mutualistic interactions between fungi and the roots of woody plants. During symbiosis the two organisms exchange carbon and nutrients in a specific tissue that is formed at the contact between a compatible fungus and plant. There is considerable variation in the degree of host specificity among species and strains of ectomycorrhizal fungi. In this study, we have for the first time shown that this variation is associated with quantitative differences in gene expression, and with divergence in nucleotide sequences of symbiosis-regulated genes. Gene expression and sequence evolution were compared in different strains of the ectomycorrhizal fungus Paxillus involutus; the strains included Nau, which is not compatible with birch and poplar, and the two compatible strains Maj and ATCC200175. On a genomic level, Nau and Maj were very similar. The sequence identity was 98.9% in the 16 loci analysed, and only three out of 1075 genes analysed by microarray-based hybridizations had signals indicating differences in gene copy numbers. In contrast, 66 out of the 1075 genes were differentially expressed in Maj compared to Nau after contact with birch roots. Thirty-seven of these symbiosis-regulated genes were also differentially expressed in the ATCC strain. Comparative analysis of DNA sequences of the symbiosis-regulated genes in different strains showed that two of them have evolved at an enhanced rate in Nau. The sequence divergence can be explained by a decreased selection pressure, which in turn is determined by lower functional constraints on these proteins in Nau as compared to the compatible strains.

Base Sequence↗
PubMed2003

Behavior of the hobo transposable element with regard to TPE repeats in transgenic lines of Drosophila melanogaster.

The hobo transposable element of Drosophila melanogaster is known to induce a hybrid dysgenesis syndrome. Moreover it displays a polymorphism of a microsatellite in its coding region: TPE repeats. In European populations, surveys of the distribution of hobo elements with regard to TPE repeats revealed that the 5TPE element is distributed along a frequency gradient, and it is even more frequent than the 3TPE element in Western populations. This suggests that the invasive ability of the hobo elements could be related to the number of TPE repeats they contain. To test this hypothesis we monitored the evolution of 16 lines derived from five initial independent transgenic lines bearing the 3TPE element and/or the 5TPE element. Four lines bearing 5TPE elements and four bearing 3TPE elements were used as a noncompetitive genetic background to compare the evolution of the 5TPE element to that of the 3TPE element. Eight lines bearing both elements provided a competitive genetic context to study potential interactions between these two elements. We studied genetic and molecular aspects of the first 20 generations. At the molecular level, we showed that the 5TPE element is able to spread within the genome at least as efficiently as the 3TPE element. Surprisingly, at the genetic level we found that the 5TPE element is less active than the 3TPE element, and moreover may be able to regulate the activity of the 3TPE element. Our findings suggest that the invasive potential of the 5TPE element could be due not only to its intrinsic transposition capacity but also to a regulatory potential.

Animals↗
PubMedDate not supplied

Regulatory punctuated equilibrium and convergence in the evolution of developmental pathways in direct-developing sea urchins.

We made hybrid crosses between closely and distantly related sea urchin species to test two hypotheses about the evolution of gene regulatory systems in the evolution of ontogenetic pathways and larval form. The first hypothesis is that gene regulatory systems governing development evolve in a punctuational manner during periods of rapid morphological evolution but are relatively stable over long periods of slow morphological evolution. We compared hybrids between direct and indirect developers from closely and distantly related families. Hybrids between eggs of the direct developer Heliocidaris erythrogramma and sperm of the 4-million year distant species H. tuberculata, an indirect developer, restored feeding larval structures and paternal gene expression that were lost in the evolution of the direct-developing maternal parent. Hybrids resulting from the cross between eggs of H. erythrogramma and sperm of the 40-million year distant indirect-developer Pseudoboletia maculata are strikingly similar to hybrids between the congeneric hybrids. The marked similarities in ontogenetic trajectory and morphological outcome in crosses of involving either closely or distantly related indirect developing species indicates that their regulatory mechanisms interact with those of H. erythrogramma in the same way, supporting remarkable conservation of molecular control pathways among indirect developers. Second, we tested the hypothesis that convergent developmental pathways in independently evolved direct developers reflect convergence of the underlying regulatory systems. Crosses between two independently evolved direct-developing species from two 70-million year distant families, H. erythrogramma and Holopneustes purpurescens, produced harmoniously developing hybrid larvae that maintained the direct mode of development and did not exhibit any obvious restoration of indirect-developing features. These results are consistent with parallel evolution of direct-developing features in these two lineages.

Animals↗
PubMed1997

Neural Network Models of Strategy Development in Children.

This paper presents new models of strategy development in young children. Traditional approaches to strategy development: (a) have relied on top-down mechanisms; (b) have not incorporated situational influences; (c) have not been biologically motivated. Neural networks models are described which address the limitations of these traditional approaches. The development of the models was influenced by: (a) Grossberg's modular approach to neural networks; (b) the general theoretical framework of Siegler; (c) empirical research on external representation and memory. Empirically, in situations requiring memory for the arrangement of objects, younger children frequently use simple external memory strategies (e.g. pointing at objects) whereas older children tend toward more advanced strategies (e.g. inter-object orienting) to aid remembering. Computer simulations with the novelty bias model show that strategy novelty and accuracy history can account for selection and evolution of strategies from simple to advanced and for accuracy patterns associated with strategies of different degrees of sophistication. Simulations with a second model, the components model, which overcomes some of the limitations of the first model, demonstrate comparable behavioural evolution using accuracy feedback and selective encoding mechanisms. The models suggest alternatives to the traditional approaches to strategy development, and suggest that the strategy evolution mechanisms involved may apply to a variety of situations. Copyright 1996 Elsevier Science Ltd.

Journal Article↗
PubMed1990

Intradialytic body weight changes and dialyzer pore size as main contributing factors to the evolution of beta-2-microglobulin in dialysis.

Cuprophane hemodialysis is associated with an early fall of leukocyte counts and an intradialytic rise in serum beta 2-microglobulin (beta 2M), in contrast to dialysis with more compatible dialyzers. It has been suggested that these two phenomena may be related. This study sets out to verify this hypothesis by comparing the evolution of leukocyte counts with that of beta 2M: (1) during dialysis with 5 dialyzer types with different pore size and/or leukocyte biocompatibility; (2) during first use and reuse of 3 dialyzer types, and (3) during sequential ultrafiltration and dialysis with cuprophane. In first-use dialyses, no relation could be found between changes in leukocyte counts and the evolution of beta 2M levels. Reuse of cuprophane and saponified cellulose ester resulted in a marked attenuation of the intradialytic fall in leukocyte counts after 15 min (change in white blood cell count: -72 and -17% for first-use and third-reuse cuprophane, -72 and -23% for saponified cellulose, respectively), but had no influence on the increase in beta 2M. Correlation studies of these data revealed that the intradialytic evolution of beta 2M was related to membrane pore size and, for membranes with a small pore size, to the intradialytic fluid losses: first-use cuprophane (p less than 0.05), saponified cellulose ester (p less than 0.001) and hemophane (p less than 0.01), and pooled first-use and reuse cuprophane and saponified cellulose ester (p less than 0.001). Cuprophane dialysis without ultrafiltration (dialysate Na+: 138 and 132 mEq/l) caused a fall in leukocytes, but induced no rise in beta 2M. Ultrafiltration with cuprophane either preceding or following dialysis consistently caused a rise in serum beta 2M, although a fall in leukocyte counts only occurred in the first case. Our data point away from a relationship between membrane biocompatibility, expressed as changes in leukocyte counts, and beta 2M concentration during hemodialysis. The major contributing factors appear to be dialytic fluid losses and membrane pore size.

Biocompatible Materials↗
PubMed1999

Effects of revascularization after first acute myocardial infarction on the evolution of QRS complex changes (the DANAMI trial). DANish Trial in Acute Myocardial Infarction.

The changes in QRS complex morphology associated with acute myocardial infarction (AMI) can resolve spontaneously over time. Whether complete revascularization of the infarct-related myocardial territory after AMI affects this QRS resolution has not been studied adequately. The present study compares the evolution of the changes in the QRS complex associated with AMI during 1-year follow-up in patients treated with or without revascularization after their first thrombolyzed AMI. The study is a substudy of the DANish Trial in Acute Myocardial Infarction (DANAMI) (n = 1,008) that randomized patients with inducible ischemia after their first AMI, treated with intravenous thrombolytic therapy, to conservative treatment or coronary angiography followed by the appropriate revascularization strategy. A total of 817 patients had complete sets of evaluable electrocardiograms. Electrocardiograms were obtained at randomization, and at 3, 6, and 12 months of follow-up and subjected to blinded core-laboratory evaluation according to the Selvester QRS scoring method. This score considers Q-, R-, and S-wave duration and ratios to provide a semiquantitative estimate of AMI size. The median electrocardiographic estimated infarct size in the entire population was 15% of the left ventricle at randomization. At the end of the follow-up period this estimate had decreased to 12% (p < 0.00001). There was no difference in the rate of QRS resolution whether the patients were subgrouped according to randomization or subgrouped according to actual treatment with or without revascularization. The present study confirms the findings from previous studies conducted in the prethrombolytic era, that considerable normalization of the QRS complex also occurs after AMI treated with thrombolytic therapy. This QRS normalization seems unaffected by an aggressive treatment strategy with revascularization via balloon angioplasty or bypass surgery.

Adult↗
PubMed1988

Longitudinal evolution of individuals having appealed their committal to the C.A.S.

The longitudinal evolution of 66 patients admitted between 1976 and 1986 at the Centre Hospitalier Robert-Giffard, and who have appealed their case before the Commission des Affaires Sociales (C.A.S.) was studied. After a review of the literature, the authors compare the evolution of the patients whose appeal was accepted and who left the hospital against medical advice to those individuals whose appeal was rejected. The authors wanted to see if the first group of patients had a less favourable short-term and medium term evolution. From a study of the files and of the case notes prepared by the physicians for the C.A.S. hearings, the authors draw a profile of the typical individual of this group and they study the influence of 16 factors of dangerousness on the Commission's decisions. The results show that the short and medium term evolution of the patients who have appealed their case before the Commission does not differ significantly in the area of dangerousness, whether their appeal was accepted or rejected. However, the length of stay of those patients who had to remain in hospital was significantly longer and that may be the reason why the period of time between their discharge and their re-hospitalization was afterwards much longer. In light of these results, the authors comment on the importance given by the Commission to the legalistic rather than therapeutic aspects of cases.

Adult↗
PubMed2003

Plasticity of the enteric nervous system in patients with intestinal neuronal dysplasia associated with Hirschsprung's disease: a report of three patients.

Intestinal neuronal dysplasia is a controversial form of dysganglionosis that has been described both as an isolated disorder and in association with Hirschsprung's disease. It has been blamed for the bad outcome of bowel function in patients operated on for Hirschsprung's disease. According to various authors, intestinal neuronal dysplasia could be a primary disorder or secondary to other diseases of the bowel. The aim of this study was to assess the plasticity of the enteric nervous system in patients with Hirschsprung's disease-associated intestinal neuronal dysplasia and its ability to evolve spontaneously to normal innervation patterns. Since we prospectively introduced the assessment of the enteric nervous system of the ganglionated bowel in patients operated on for Hirschsprung's disease, 31 patients have been operated on for Hirschsprung's disease in our institution between 1995 and 2002. Among these patients, nine suffered postoperatively from severe constipation and five from bouts of entocolitis. IND was found in eight of them. We studied the evolution of the innervation in three of these patients by repeated serial full-thickness biopsies of the colon. All three patients underwent a colostomy before or after the pull-through procedure. Histopathological assessment of the enteric nervous system was made with conventional acetylcholinesterase histochemistry, rapid acetylcholinesterase histochemistry and immunohistochemistry for the Protein Gene Product 9.5 and the antigen CD56. This evolution was compared with the clinical outcome of bowel function. In our three patients with Hirschsprung's disease-associated intestinal neuronal dysplasia, this form of dysganglionosis evolved to normal innervation patterns within a period ranging from 9 to 18 months. This evolution was accompanied by an improvement of bowel function in all. We conclude that Hirschsprung's disease-associated intestinal neuronal dysplasia can evolve to a normal innervation, at least under certain circumstances such as a colostomy. Specific histopathological techniques are required to assess accurately the enteric nervous system.

Colon↗
PubMed2004

Recurrent sites for new centromere seeding.

Using comparative FISH and genomics, we have studied and compared the evolution of chromosome 3 in primates and two human neocentromere cases on the long arm of this chromosome. Our results show that one of the human neocentromere cases maps to the same 3q26 chromosomal region where a new centromere emerged in a common ancestor of the Old World monkeys approximately 25-40 million years ago. Similarly, the locus in which a new centromere was seeded in the great apes' ancestor was orthologous to the site in which a new centromere emerged in the New World monkeys' ancestor. These data suggest the recurrent use of longstanding latent centromeres and that there is an inherent potential of these regions to form centromeres. The second human neocentromere case (3q24) revealed unprecedented features. The neocentromere emergence was not accompanied by any chromosomal rearrangement that usually triggers these events. Instead, it involved the functional inactivation of the normal centromere, and was present in an otherwise phenotypically normal individual who transmitted this unusual chromosome to the next generation. We propose that the formation of neocentromeres in humans and the emergence of new centromeres during the course of evolution share a common mechanism.

Animals↗
PubMedDate not supplied

A comparative genomics approach to the evolution of eukaryotes and their mitochondria.

The Organelle Genome Megasequencing Program (OGMP) investigates mitochondrial genome diversity and evolution by systematically determining the complete mitochondrial DNA (mtDNA) sequences of a phylogenetically broad selection of protists. The mtDNAs of lower fungi and choanoflagellates are being analyzed by the Fungal Mitochondrial Genome Project (FMGP), a sister project to the OGMP. Some of the most interesting protists include the jakobid flagellates Reclinomonas americana, Malawimonas jakobiformis, and Jakoba libera, which share ultrastructural similarities with amitochondriate retortamonads, and harbor mitochondrial genes not seen before in mtDNAs of other organisms. In R. americana and J. libera, gene clusters are found that resemble, to an unprecedented degree, the contiguous ribosomal protein operons str, S10, spc, and alpha of eubacteria. In addition, their mtDNAs code for an RNase P RNA that displays all the elements of a bacterial minimum consensus structure. This structure has been instrumental in detecting the rnpB gene in additional protists. Gene repertoire and gene order comparisons as well as multiple-gene phylogenies support the view of a single endosymbiotic origin of mitochondria, whose closest extant relatives are Rickettsia-type alpha-Proteobacteria.

Animals↗
PubMed1991

Pedigrees of neurobehavioral circuits: tracing the evolution of novel behaviors by comparing motor patterns, muscles, and neurons in members of related taxa.

Comparisons of homologous elements in neurobehavioral circuits that have diverged during speciation to mediate different behaviors should reveal the nature of evolutionary changes in nervous systems. When the pedigree of a particular behavior can be traced-by comparing motor patterns and their neural substrates in related taxa whose phylogeny is known from other (non-neurobehavioral) criteria-divergent and convergent evolutionary changes can be distinguished and the order of their occurrence reconstructed. An example of reconstructing a behavioral pedigree (for the novel mode of swimming in the crab Emerita [Hippidae]) is presented, and implications about the evolution and organization of neurobehavioral circuits engendered by this and some other studies of functionally defined neuronal networks are reviewed. Specific neural differences in related animals can only be attributed to natural selection when they can be related to species differences in function or behavior. Differences that cannot be so related, as well as apparently non-adaptive characters in individual nervous systems, are attributed to ontogenetic processes, which apparently, in some cases, introduced and, in other cases, resisted change through evolutionary time. More expressly-comparative investigations of discrete neurobehavioral circuits are needed for an understanding of the interdependence of evolutionary processes and ontogenetic and functional constraints on the organization of neuronal systems.

Animals↗
PubMed1996

[Criteria for somatization studied in an outpatient clinic for general internal medicine].

OBJECTIVE: To compare the evolution of bodily symptoms and the frequency of medical consultation using three different operational definitions of 'somatization'. DESIGN: Descriptive follow-up study. SETTING: General Internal Medicine Outpatient Clinic of Leiden University Hospital, the Netherlands. METHOD: Information about physical and psychic symptoms and about the somatic-medical diagnosis was collected in a group of 158 newly referred patients. The concept of 'somatization' was operationalized in three ways: a) seeking medical consultation for somatically unexplained symptoms; b) seeking medical consultation for somatically unexplained symptoms combined with an anxiety disorder or a depressive disorder according to the 'present state examination'; c) seeking medical consultation for somatically unexplained symptoms combined with a somatization disorder or hypochondria according to the Diagnostic and statistical manual of mental disorders (DSM) III R criteria. After a follow-up period of 1.2 years, information was collected from the entire study group about the evolution of the physical symptoms and the frequency of medical consultation. RESULTS: Patients with somatically unexplained symptoms combined with a somatization disorder or hypochondria were characterized in the follow-up by numerous physical symptoms and a high frequency of medical consultation. Compared with the other patients with unexplained symptoms, they visited the general practitioner during the follow-up period 2.5 times as often, saw specialists twice as often and were admitted to a 'somatic' hospital, 6 times as often. CONCLUSION: Using criteria of low restrictiveness for somatization, a large group of patients were identified with a relatively normal (average) illness behaviour. Using more restrictive criteria led to identification of a smaller group with more extreme illness behaviour.

Adult↗