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PubMed1998

A strategy for the use of cardiac injury markers (troponin I and T, creatine kinase-MB mass and isoforms, and myoglobin) in the diagnosis of acute myocardial infarction.

OBJECTIVE: To design a strategy for cardiac injury marker testing in the diagnosis of acute myocardial infarction. DESIGN: Prospective study. Group I (n=54 patients): evaluation of clinical performance. Specimens collected at 0, 3, 6, and 12 (+/-1.5) hours after presentation. World Health Organization criteria were used for diagnosis of acute myocardial infarction. Group II (n=57 patients): evaluation of temporal evolution. Time intervals 0 to 1.5, 1.5 to 4.5, 4.5 to 7.5, and 7.5 to 13.5 hours. Patients identified by positive creatine kinase-MB (CK-MB) mass or myoglobin. Fourteen patients in Group I qualified for Group II. Hence, the total number of patients was 97. SETTING: A team of laboratorians and clinicians at the University of California, Davis, hospital assessed the clinical performance and temporal evolution of serial CK-MB isoform, troponin I, and troponin T results in comparison to parallel CK-MB mass and myoglobin results. MAIN OUTCOME MEASURES: Group I: sensitivity, specificity, and positive and negative predictive values. Group II: the time interval of the first positive result for each cardiac injury marker. Strategy and conclusions were based on study results and a literature review. PARTICIPANTS: Emergency department patients with acute onset of chest pain and other complaints, possibly indicative of myocardial ischemia, who were under evaluation for admission. RESULTS: Twenty-seven cases of acute myocardial infarction were documented. Group I: troponin I had the highest specificity (100%) and the highest positive predictive value (100%); troponin I, troponin T, and CK-MB mass had the highest sensitivity (90.0%); and the negative predictive values of troponin I, troponin T, and CK-MB mass were comparable (97.8%, 97.6%, and 97.6%, respectively). Group II: early diagnosis (within 1.5 hours) was provided by both CK-MB isoforms and CK-MB mass, and then by myoglobin and troponins, in order of decreasing frequency. CONCLUSIONS: Creatine kinase-MB mass, myoglobin, and troponin I were selected as the cardiac injury markers of choice at our institution. The strategy calls for serial testing of myoglobin and CK-MB mass initially-and serially if warranted by heightened clinical suspicion--with troponin I added if indicated for (1) specific confirmation, (2) late presentation, or (3) risk stratification.

Biomarkers↗

PubMed2002

Multiple parallel synthesis of peptides on SynPhase grafted supports.

The Multipin peptide synthesis approach originated as an immunological tool for epitope mapping. However, continuing evolution of the basic technology has permitted the synthesis of peptides at scales up to 25 micromol per modular grafted surface. At this loading, the methodology can no longer be considered just a screening tool and is now used for the synthesis of micromoles of peptide and other small drug-like molecules for high throughput compound screening. Recent developments such as the introduction of novel grafted polymeric surfaces, new linkers, as well as novel cleavage formats has extended the scope of applications for modular grafted surfaces. This review summarizes the important achievements over the last 15 years of applications of the Multipin synthesis approach and also introduces a new modular grafted surface for peptide and small molecule synthesis called the SynPhase Lantern.

Combinatorial Chemistry Techniques↗

PubMed2002

Bird song, ecology and speciation.

The study of bird song dialects was once considered the most promising approach for investigating the role of behaviour in reproductive divergence and speciation. However, after a series of studies yielding conflicting results, research in the field slowed significantly. Recent findings, on how ecological factors may lead to divergence in both song and morphology, necessitate a re-examination. We focus primarily on species with learned song, examine conflicting results in the literature and propose some potential new directions for future studies. We believe an integrative approach, including an examination of the role of ecology in divergent selection, is essential for gaining insight into the role of song in the evolution of assortative mating. Habitat-dependent selection on both song and fitness-related characteristics can lead to parallel divergence in these traits. Song may, therefore, provide females with acoustic cues to find males that are most fit for a particular habitat. In analysing the role of song learning in reproductive divergence, we focus on post-dispersal plasticity in a conceptual framework. We argue that song learning may initially constrain reproductive divergence, while in the later stages of population divergence it may promote speciation.

Animals↗

PubMed2001

Evolution of larval form in the sea star genus Patiriella: conservation and change in the larval nervous system.

The organization of the peptidergic system in the larvae of Patiriella species with divergent ontogenies was compared to determine which aspects of neurogenesis are conserved and which are altered in the evolution of development in these sea stars. P. regularis has ancestral-type feeding bipinnaria and brachiolaria larvae and the organization of the nervous system, in association with feeding structures, paralleled the bilateral larval body plan. P. calcar and P. exigua have non-feeding planktonic and benthic brachiolariae, respectively, and there was no trace of the neuronal architecture involved with feeding. The nervous system in the attachment stage brachiolaria was similar in all three species and neuronal organization reflected larval symmetry. Delayed expression of peptidergic lineages to the brachiolaria stage in the lecithotrophs indicates heterochronic change in the timing of neurogenesis or deletion of the ancestral early neurogenic program. The bipinnarial program is suggested to be a developmental module autonomous from the brachiolar one. With a divergence time of less than 10 Ma, the evolution of development in Patiriella has resulted in extensive reduction in the complexity of the larval nervous system in parallel with simplification in larval form. There is, however, strong conservation in the morphology and neuronal architecture of structures involved with settlement.

Animals↗

PubMed2002

Correlation between transient shear experiments and structure evolution of aqueous foams.

This experimental work deals with rheological properties of aqueous foams and slip phenomena. Rheological measurements are performed on a stable foam with a parallel plate rheometer. When a constant shear rate is applied to foam, two regimes can be identified in the recorded stress vs time curve: a transient regime where the structure evolves and where the recorded stress varies, followed by a steady state regime where the stress is stabilized. Measurements, modeling, and elimination of the slip velocity are performed. Experiments with grooved surfaces allow elimination of slip at the wall. From measurements at two gaps with smooth surfaces, we use two slip correction methods and check their validity by a direct comparison with actual measurements (with grooved surfaces). A foam rheological equation can be determined from the measurements. Finally, using an optical device coupled with image analysis software, foam texture is investigated on the basis of its evolution with shear rate and time. Evolution of the bubbles size and arrangement into the gap with time of shearing are shown. The transient regime is identified as a regime where the intimate structure of the foam evolves. Slip velocity is also evidenced and measured with the visualization device.

Journal Article↗

PubMed1982

Phylogenetic origins and adaptive evolution of avian and mammalian haemoglobin genes.

Recent years have seen rapid growth in amino acid sequence data on globins and nucleotide sequence data on haemoglobin genes and pseudogenes, and cladistic analysis of these data continues to reveal new facets of globin evolution. Our present findings demonstrate: (1) avian and mammalian embryonic alpha genes (pi and xi, respectively) had a monophyletic origin involving an alpha locus duplication about 400 Myr ago soon after the duplication which separated alpha and beta genes; (2) much later in phylogeny, independent beta-gene duplications produced the embryonic rho locus of birds and embryonic epsilon and fetal gamma loci of mammals. This parallels the earlier finding that myoglobins evolved more than once from generalized globin ancestors. Here we support the view that such globin evolution resulted from natural selection acting on mutations in duplicated genes. Thus, our evidence contradicts the neutralist view in which almost all amino acid substitutions in descent to extant globins evaded positive selection.

Amino Acid Sequence↗

PubMed2005

First evidence of a venom delivery apparatus in extinct mammals.

Numerous non-mammalian vertebrates have evolved lethal venoms to aid either in securing prey or as protection from predators, but modern mammals that use venoms in these ways are rare, including only the duck-billed platypus (Ornithorhynchus), the Caribbean Solenodon, and a few shrews (Soricidae) (Order Insectivora). Here we report evidence of a venom delivery apparatus in extinct mammals, documented by well-preserved specimens recovered from late Palaeocene rocks in Alberta, Canada. Although classified within Eutheria, these mammals are phylogenetically remote from modern Insectivora and have evolved specialized teeth as salivary venom delivery systems (VDSs) that differ markedly from one another and from those of Solenodon and shrews. Our discoveries therefore show that mammals have been much more flexible in the evolution of VDSs than previously believed, contradicting currently held notions that modern insectivorans are representative of the supposedly limited role of salivary venoms in mammalian history. Evidently, small predatory eutherians have paralleled colubroid snakes in evolving salivary venoms and their delivery systems several times independently.

Alberta↗

PubMedDate not supplied

The evolution of the clinician-scientist model of neurological rehabilitation.

Over the past three or four decades two treatment technologies have been evolving in parallel, recently to some extent merging. The first of these technologies is behaviour analysis, with its emphasis on identification and manipulation of variables external to the individual as controlling agents. The second is neurological rehabilitation, with a characteristic focus of resources on recovery of function following neurological damage. The histories of both of these technologies are similar in that they emerged from basic laboratory research with non-human subjects, followed by extension of findings to research with humans, culminating in widespread formal application of results. The past 5 years have seen a convergence of behaviour analytic and neurological rehabilitation techniques resulting in major shifts in treatment service delivery systems. We briefly chronicle the emergence of these two technologies from their basic underpinnings through world-wide use. Further, discussion is provided describing our and others' experience with the combining of behaviour and neurological rehabilitation. Finally, we give an account of an innovative neurological rehabilitation service delivery system designed to deliver effective cost-efficient treatment in the patient's natural environment. Implicit in the design and implementation of this real-world model of rehabilitation is the combination of behavioural technology and neurological rehabilitation towards the achievement of functional outcomes which endure. Our purpose in the above is to provide an introduction to present use and future potential of behaviour analytic methodologies and technologies in rehabilitation.

Ambulatory Care↗

PubMed2001

Evolution and development: some insights from evolutionary theory.

Developmental biology and evolutionary biology are both mature integrative disciplines which started in the 19th century and then followed parallel and independent scientific pathways. Recently, a genetical component has stepped into both disciplines (developmental genetics and evolutionary genetics) pointing out the need for future convergent maturation. Indeed, the Evo-Devo approach is becoming popular among developmental biologists, based on the facts that distant groups share a common ancestry, that precise phylogenies can be worked out and that homologous genes often play similar roles during the development of very different organisms. In this essay, I try to show that the real future of Evo-Devo thinking is still broader. The evolutionary theory is a set of diverse concepts which can and should be used in any biological field. Evolutionary thinking trains to ask << why >> questions and to provide logical and plausible answers. It can shed some light on a diversity of general problems such as how to distinguish homologies from analogies, the costs and benefits of multicellularity, the origin of novel structures (e.g. the head), or the evolution of sexual reproduction. In the next decade, we may expect a progressive convergence between developmental genetics and quantitative genetics.

Animals↗

PubMed2006

Advances in imaging of the paranasal sinuses.

Imaging technology has played a significant role in the diagnosis and management of sinonasal disorders. Plain sinus films are almost exclusively replaced by CT in the work-up for inflammatory sinus disease. MRI provides complementary information to CT in cases of sinonasal and skull-base neoplasms. The evolution of endoscopic surgical techniques for the paranasal sinuses and skull base is made possible by the parallel advancement of imaging technologies. Recent advances that are currently in clinical use have included multidetector row CT scanners and computer image-guidance systems for surgery. Three-dimensional CT angiography, image-guided CT-MR fusion, and intraoperative image-guidance are new techniques that are currently being evaluated. As imaging technology continues to advance, so does the capability to treat diseases beyond the sinuses and skull base with minimally invasive, endoscopic approaches.

Humans↗

PubMed1985

Comparative study of DHBV DNA levels and endogenous DNA polymerase activity in naturally infected ducklings in France.

Duck hepatitis B virus (DHBV) was found in the serum of 1-6% of Pekin ducklings originated from French commercial flocks. The viremia was followed in the serum of 5 ducklings over a span of 3 mth by monitoring the levels of DHBV DNA and the endogenous DNA polymerase (DNAp) activity. The DHBV DNA levels in serum were quantified either by the DNA dot hybridization technique including counting of retained radioactivity, or by successive dilutions of each serum sample followed by DNA hybridization. The counting of the retained radioactivity was plotted on a curve and its evolution compared with that of viral DNAp activity. DHBV DNA levels in serum, estimated by both methods paralleled those of the DNAp activity, which peaked at the 4th or 5th week posthatch to decrease and fluctuate thereafter. Occasional discordance between DHBV DNA levels and the endogenous DNAp activity was observed, which could be correlated with the degree of repair of the single stranded gap of serum DHBV DNA. Parallel follow up studies comparing quantitative estimations of serum viral DNA and of DNAp activity, as presented here, may provide some clues for the understanding of the mechanisms involved in the establishment of the HEPA DNA virus carrier state. Such comparative studies may also be crucial for optimal monitoring of antiviral drugs in both human clinical trials and animal experimental studies.

Animals↗

PubMed1989

Auditory primary afferents in the starling: correlation of function and morphology.

Despite the independent evolution of birds and mammals, a number of structural similarities of their hearing organs have developed in parallel. By tracing the peripheral origin of functionally-characterized primary neurons, the present study demonstrates functional similarities between the respective hair cell populations of the hearing organs of birds and mammals. The space devoted to one octave on the starling's basilar papilla is not constant over the whole length; rather it increases from the apical low- to the basal high-frequency end. The finding that (with the exception of a specialized area near the apical end) only tall hair cells situated on the neural limbus receive active afferent innervation is a functional parallel to the mammalian inner hair cells. The thresholds of afferents increase with distance of the related hair cells from the neural side of the papilla and cover a range of more than 50 dB within the area of tall hair cells.

Acoustic Stimulation↗

PubMed1998

An ancient system of host defense.

Research over the past few years has begun to provide significant advances in our understanding of the interplay between the innate and adaptive immune systems. New findings in several model systems reveal remarkable parallels and conservation of ancient host defense pathways in organisms separated by over a billion years of evolution.

Animals↗

PubMed2002

Steady-state voltammetry of hydroxide ion oxidation in aqueous solutions containing ammonia.

An oxidation process observed in dilute aqueous solutions of ammonia was investigated under steady-state conditions with gold microelectrodes with radii in the range 2.5-30 microm. Over the ammonia concentration range 0.1-10 mM, a well-defined voltammetric wave was observed at approximately 1.4 V versus Ag/AgCl. It was attributed to the oxidation of hydroxide ions that arise from the dissociation of the weak base. The steady-state limiting current was found to depend on the concentration of supporting electrolyte, and in solution with low electrolyte, it was enhanced by migration contribution, as expected for a negatively charged species that oxidizes on a positively charged electrode. In addition, the steady-state limiting current was proportional to both the ammonia concentration and the electrode radius. The overall electrode process was analyzed in terms of a CE mechanism (homogeneous chemical reaction preceding the heterogeneous electron transfer) with a fast chemical reaction when measurements were carried out in solutions containing NH3 at < or = 5 mM and with electrodes having a radius of > or = 5 microm. This was ascertained by comparing experimental and theoretical data obtained by simulation. The formation of the soluble complex species Au(NH3)2+ was also considered as a possible alternative to explain the presence of the oxidation wave. This process however was ruled out, as the experimental data did not fit theoretical predictions in any of the conditions employed in the investigation. Instead, the direct oxidation of NH3, probably to N2O, was invoked to explain the anomalous currents found when the CE process was strongly kinetically hindered. Throughout this study, a parallel was made between the CE mechanism investigated here and that known to occur during the hydrogen evolution reaction from weak acids.

Journal Article↗

PubMed2003

Applicants' opinions about the selection process for oral and maxillofacial surgery programs.

PURPOSE: This study was conducted to investigate the characteristics of and opinions about the selection process of applicants to residency programs in oral and maxillofacial surgery (OMS) in the year 2000. The current investigation paralleled a survey completed in the 1970s, with additional questions to assess contemporary curriculum and surgical training evolution. Differences from the previous (1976) survey, a profile of applicants in 2000, and characteristics of OMS residency programs that applicants view as attractive are discussed. SUBJECTS AND METHODS: Questionnaires were sent to 307 applicants to OMS residency programs registered in the dental matching program. To provide a more direct comparison of the study completed in 1977, the current questionnaire used the original survey as a model. It was divided into 6 sections: general information, information from the formal application and letters of recommendation, the interview, the selection process, the characteristics applicants were seeking in a program, and a retrospective review of programs visited. RESULTS: In this study, 118 responses were received, representing 38% of the total. Respondents were predominately men (86%) and single, and attended dental school in all regions of the United States and the world. Respondents listed geographic location (65%) and national reputation (58%) as important factors for selecting programs to which to apply. Many respondents felt that a previous dental internship (85%), national board scores (83%), and class rank (79%) would be considered important in screening applicants for interview. A program's reputation, personalities of residents and attending staff, and clinical material were ranked as important factors contributing to program selection. Fifty-three of the 79 successful applicants reported that they were matched with their first-choice institution. Sixty percent of programs were considered worthy of revisiting by the respondents. CONCLUSIONS: Respondents in 2000 had more knowledge of the selection process before interviewing and submitted 2 times the number of applications than applicants in 1977. When selecting programs to which to apply, current applicants were less influenced by geographic location and the recommendations of other dentists. Applicants were attracted to programs that they perceive to have a good reputation and abundant clinical material. Residencies that convey a friendly atmosphere, favorable interpersonal skills of enrolled residents, and appealing personalities of the faculty were more attractive to candidates.

Adult↗

PubMed1994

Femtosecond photodichroism studies of isolated photosystem II reaction centers.

Photosynthetic conversion of light energy into chemical potential begins in reaction center protein complexes, where rapid charge separation occurs with nearly unit quantum efficiency. Primary charge separation was studied in isolated photosystem II reaction centers from spinach containing 6 chlorophyll a, 2 pheophytin a (Pheo), 1 cytochrome b559, and 2 beta-carotene molecules. Time-resolved pump-probe kinetic spectroscopy was carried out with 105-fs time resolution and with the pump laser polarized parallel, perpendicular, and at the magic angle (54.7 degrees) relative to the polarized probe beam. The time evolution of the transient absorption changes due to the formation of the oxidized primary electron donor P680+ and the reduced primary electron acceptor Pheo- were measured at 820 nm and 545 nm, respectively. In addition, kinetics were obtained at 680 nm, the wavelength ascribed to the Qy transition of the primary electron donor P680 in the reaction center. At each measured probe wavelength the kinetics of the transient absorption changes can be fit to two major kinetic components. The relative amplitudes of these components are strongly dependent on the polarization of the pump beam relative to that of the probe. At the magic angle, where no photoselection occurs, the amplitude of the 3-ps component, which is indicative of the charge separation, dominates. When the primary electron acceptor Pheo is reduced prior to P680 excitation, the 3-ps component is eliminated.

Chlorophyll↗

PubMed2002

Development in frogs with large eggs and the origin of amniotes.

The origin of the amniote egg is one of the most significant events in the evolution of terrestrial vertebrates. This innovation was probably driven by increased egg size, and to find potential parallels, we can examine the derived development of extant amphibians with large eggs. The embryo of the Puerto Rican tree frog, Eleutherodactylus coqui, exhibits an alteration of its fate map and a secondary coverage of its yolky cells, reflecting the large 3.5 mm egg. Comparable changes may have occurred with the derivation of an amniote pattern of development. Future investigations should focus on the molecular organization of the egg. In the model amphibian for development, Xenopus laevis, information for embryonic germ layers, the dorsal axis, and germ cells is stored mainly as localized RNAs at the vegetal pole of the egg. These localizations would likely be changed with increased egg size. A review of the orthologues of the key X. laevis genes raises the possibility that their activities are not conserved in other vertebrates.

Journal Article↗

PubMed2001

Partial recovery of light-independent chlorophyll biosynthesis in the chlL-deletion mutant of Synechocystis sp. PCC 6803.

A chlL-deletion mutant of Synechocystis sp. PCC 6803 designated as chlL- was unable to make significant amounts of chlorophyll in darkness. However, an apparent pseudorevertant has been generated spontaneously that can synthesize an increased amount of chlorophyll under light-activated heterotrophic growth conditions. Under these conditions, the chlorophyll content in this pseudorevertant was about 20% of that in the wild-type strain and about 4 times more than that in the original and in the recently recreated chlL-deletion mutant. This is paralleled by increased performance of dark-grown cells in terms of chlorophyll fluorescence induction and oxygen evolution rates in the pseudorevertant versus in the original mutant. PCR analysis confirmed that the chlL- -pseudorevertant mutant still lacked the chlL gene. These results imply that the light-independent chlorophyll biosynthesis pathway was partly recovered.

Bacterial Proteins↗