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Teeth have a very significant place in paleoanthropology. Their number is one of the keys of the primate taxonomy and classification. They have been used for systematics, phylogeny, paleobiology, or paleoenvironment. Some examples are given on the use of dental formula, morphology, wear or microwear, and biogeochemistry in paleoanthopologic studies.
The national Area Health Education Center (AHEC) program began in 1972 with the purpose of addressing problems of the shortage of physicians and the maldistribution of health professionals. The 40 projects of the program have involved 37 states, 55 medical schools, numerous other health professions schools, and 117 local community AHECs. This 19-month study (1988-1990) was undertaken to systematically assess and clarify the organization, functions, activities, and effects of the national AHEC program over two decades. Data sources were mainly 263 interviews of persons representing the full spectrum of those associated with and participating in AHECs. The findings describe a national network of school and community partnerships that were engaged in planning and implementing educational activities and were responsive to changing needs of health care. The individual AHECs differ in structure and activities as a function of the era in which each began, legislative requirements, and the specific community's needs for health professionals. As organizations, AHECs have unique functions that appear to have benefited the target communities or regions, participating schools, students, and medical school residents. Viability of AHECs in the future will depend on their ability to maintain a focus on health professions education in spite of state or community pressure to provide direct services--both clinical services and public education. At the same time, success will depend on the AHECs' capacity to respond effectively to changing needs of the community and the health care delivery system.
For 25,368 serologies examined in the biological laboratory of National Hospital of Niamey, Niger, from March 1987 to May 1990, the authors studied seroprevalence HIV1, HIV2 and HIV1 + HIV2 during this periode in the different groups studied: Blood donors, in women patients of child bearing age, pregnant women, prostitutes, prisoners and during systematic visits. It appears there is a tendancy of an increase in HIV1, a decrease in HIV2 and relative stability for the two profiles together.
The regulators of G-protein signaling (RGS) proteins are important regulatory and structural components of G-protein coupled receptor complexes. RGS proteins are GTPase activating proteins (GAPs) of Gi-and Gq-class Galpha proteins, and thereby accelerate signaling kinetics and termination. Here, we mapped the chromosomal positions of all 21 Rgs genes in mouse, and determined human RGS gene structures using genomic sequence from partially assembled bacterial artificial chromosomes (BACs) and Celera fragments. In mice and humans, 18 of 21 RGS genes are either tandemly duplicated or tightly linked to genes encoding other components of G-protein signaling pathways, including Galpha, Ggamma, receptors (GPCR), and receptor kinases (GPRK). A phylogenetic tree revealed seven RGS gene subfamilies in the yeast and metazoan genomes that have been sequenced. We propose that similar systematic analyses of all multigene families from human and other mammalian genomes will help complete the assembly and annotation of the human genome sequence.
OBJECTIVE: The study of epileptic electroencephalograph (EEG) dynamics can potentially provide insights into seizure onset, evolution and termination. We propose a new synthetic measure based on time-frequency decomposition to provide detailed characterization of these dynamic changes. METHODS: The matching pursuit (MP) method allows for continuous time-frequency decomposition. We have developed a derivative of the MP method, the Gabor atom density method (GAD) that facilitates interpretation during the dynamic ictal period. The GAD analysis was applied to intracranial recordings of complex partial seizures (n = 43) of mesial temporal origin in 7 patients. RESULTS: Complex partial seizure occurrence is systematically associated with a GAD increase of 400 +/- 150%. The GAD increase coincides with the electrographical evidence of seizure onset. The similarity between seizures in a given patient is very high with uniform onset slope, maximum level and termination pattern. Global GAD responses over all channels can reveal detailed seizure propagation patterns including secondary independent foci and secondary generalization. CONCLUSIONS: The GAD measure based on the MP decomposition is a reliable tool to detect seizure occurrence in long-term recordings, to differentiate seizures from artifacts on a multi-channel basis and to examine patterns of seizure propagation. The reproducible GAD pattern suggests consistent changes in signal inner structure and may provide new clues about seizure dynamics and evolution. SIGNIFICANCE: The GAD method can provide information about seizure dynamics that can contribute to methods of seizure detection. These analyses may lead to better understanding of seizure termination and help facilitate application of responsive seizure control devices in humans.
The design of metabolic pathways is thought to be the result of an optimization process such that the structure of contemporary metabolic routes maximizes a particular objective function. Recently, it has been shown that some essential stoichiometric properties of glycolysis can be explained on the basis of the requirement for a high ATP production rate. Because the number of stoichiometrically feasible designs increases strongly with the number of reactions involved, a systematic analysis of all the possibilities turns out to be inaccessible beyond a certain system size. We present, therefore, an alternative approach to compute in a more efficient way the optimal design of glycolysis interacting with an external ATP-consuming reaction. The algorithm is based on the laws of evolution by natural selection, and may be viewed as a particular version of evolutionary algorithms. The following conclusions are derived: (a) evolutionary algorithms are very useful search strategies in determining optimal stoichiometries of metabolic pathways. (b) Essential topological features of the glycolytic network may be explained on the basis of flux optimization. (c) There is a strong interrelation between the optimal stoichiometries and the thermodynamic and kinetic properties of the participating reactions. (d) Some subsequences of reactions in optimal pathways are strongly conserved at variation of system parameters, which may be understood by applying principles of metabolic control analysis.
Tetrahydrobiopterin deficiency in hyperphenylalaninaemic babies has to be rapidly recognized since the disease requires a specific treatment. Based on 15 years experience, we report on the evolution of a strategy for the detection of such patients. A total of 913 hyperphenylalaninaemic patients have been studied and 15 tetrahydrobiopterin deficiencies have been detected or confirmed. DHPR assay in dried blood samples and pteridine measurement in urine collected on filter paper combine convenient sampling and reliable tests for systematic investigation of hyperphenylalaninaemic patients for cofactor deficiency.
A systematic Hamiltonian approximation scheme is developed for a stochastic-web map with fivefold quasicrystalline symmetry. Interpolating Hamiltonians are calculated up to tenth order in the control parameter a. The higher order Hamiltonians are used to provide bounds for closed invariant curves of the map, and to investigate the structural evolution of map's phase portrait for a</=0.6.
The replication control genes of bacterial plasmids face selection at two conflicting levels. Plasmid copies that systematically overreplicate relative to their cell mates have a higher chance of fixing in descendant cells, but these cells typically have a lower chance of fixing in the population. Apart from identifying the conflict, this mathematical discussion characterizes the efficiency of the selection levels and suggests how they drive the evolution of kinetic mechanisms. In particular it is hypothesized that: (1) tighter replication control is more vulnerable to selfishness; (2) cis-acting replication activators are relics of a conflict where a plasmid outreplicated its intracellular competitors by monopolizing activators; (3) high-copy plasmids with sloppy replication control arise because intracellular selection favors overreplication, thereby relieving intercellular selection for lower loss rates; (4) the excessive synthesis of cis-acting replication activators and trans-acting inhibitors is the result of an arms race between cis selfishness and trans retaliations; (5) site-specific recombination of plasmid dimers is equivalent to self-policing; and (6) plasmids modify their horizontal transfer to spread without promoting selfishness. It is also discussed how replication control may be subject to a third level of selection acting on the entire population of plasmid-containing cells.
A novel classification of planar four-bar linkages is presented based on the systematical variation of one, two or three bar lengths and studying the transmission properties (input-output curves) of the linkages. This classification is better suited to the study of biological systems than the classical Grashof-classification used in engineering as it considers the change of structural elements, in evolution for example, instead of evaluating the possibilities for the rotation of a particular bar. The mechanical features of a wide range of planar linkages in vertebrates, described by various authors, have been included in this classification. Examples are: skull-levation and jaw-protrusion mechanisms in fishes, reptiles and birds, the coral crushing apparatus of parrotfishes, and catapult-mechanisms in feeding pipefishes. Four-bar replacement mechanisms, e.g., crank-slider mechanisms in feeding systems of fishes and cam-mechanisms in mammalian limb-joints, and more complex linkages than four-bar ones, e.g., six-bar linkages and interconnected four-bar linkages in fish feeding mechanisms are also discussed. In this way, an overview is obtained of the applicability of planar linkage theory in animal mechanics to mechanical functioning and the effect of possible variations of bar lengths and working ranges in evolution. Four-bar system analysis often provides a rigorous method of simplifying the study of complex biological mechanisms. The acceptable width-range of necessary and undesired hysteresis ('play') in biological linkages is also discussed.
We study the decoherence of a quantum computer in an environment which is inherently correlated in time and space. We first derive the nonunitary time evolution of the computer and environment in the presence of a stabilizer error correction code, providing a general way to quantify decoherence for a quantum computer. The general theory is then applied to the spin-boson model. Our results demonstrate that effects of long-range correlations can be systematically reduced by small changes in the error correction codes.
18 eyes of 14 pathologic myopia patients with lacker cracks have been studied during a mean follow up of 45 months by initial and final clinical and fluoroangiography evaluation. These lacker cracks happen early in the myopia degeneration evolution in young patients. The evolution is marked by transient coinlike macular hemorrhages without CNM detectable. Prognosis for the retention of central vision after macular hemorrhages resolution is good. It mainly depends of lacker cracks initial location if macular quite wrong, if intramacular, quite right. Development of CNM is an infrequent eventuality but must be systematically research by angio-fluorography after spontaneous macular hemorrhage resolution which usually occurs 4 or 6 weeks later.
We report the complete DNA sequences of the protamine P1 gene and flanking regions for 13 species of the marsupial family Dasyuridae. The structure of the protamine locus is conserved in dasyurids and consists of two exons (of lengths 142-151 and 47 bp) separated by an intron (208-240 bp). A key feature of the dasyurid intron is a 38-40 bp duplication found in all species examined to date. This duplication apparently predates the radiation of modern dasyurid lineages and may be homologous to a similar feature in the marsupial mole (Notoryctes). Sequences from a species of Planigale demonstrate that this genus is unique among marsupials in possessing cysteine residues in its protamine P1 molecules. Cysteines may provide enhanced chemical stability for condensed sperm nuclei, a physiological feature that would converge on the common eutherian pattern. Phylogenetic analysis of the protamine genes yields a tree that is largely congruent with previous molecular systematic studies in two areas: (1) There are three main dasyurid lineages corresponding to the Sminthopsinae. Dasyurinae, and Phascogalinae; (2) Dasyurinae and Phascogalinae are sister groups. This study is the first estimate of dasyurid relationships based on a nuclear DNA sequence.
BACKGROUND: Ubiquitin (Ub)-mediated signaling is one of the hallmarks of all eukaryotes. Prokaryotic homologs of Ub (ThiS and MoaD) and E1 ligases have been studied in relation to sulfur incorporation reactions in thiamine and molybdenum/tungsten cofactor biosynthesis. However, there is no evidence for entire protein modification systems with Ub-like proteins and deconjugation by deubiquitinating enzymes in prokaryotes. Hence, the evolutionary assembly of the eukaryotic Ub-signaling apparatus remains unclear. RESULTS: We systematically analyzed prokaryotic Ub-related beta-grasp fold proteins using sensitive sequence profile searches and structural analysis. Consequently, we identified novel Ub-related proteins beyond the characterized ThiS, MoaD, TGS, and YukD domains. To understand their functional associations, we sought and recovered several conserved gene neighborhoods and domain architectures. These included novel associations involving diverse sulfur metabolism proteins, siderophore biosynthesis and the gene encoding the transfer mRNA binding protein SmpB, as well as domain fusions between Ub-like domains and PIN-domain related RNAses. Most strikingly, we found conserved gene neighborhoods in phylogenetically diverse bacteria combining genes for JAB domains (the primary de-ubiquitinating isopeptidases of the proteasomal complex), along with E1-like adenylating enzymes and different Ub-related proteins. Further sequence analysis of other conserved genes in these neighborhoods revealed several Ub-conjugating enzyme/E2-ligase related proteins. Genes for an Ub-like protein and a JAB domain peptidase were also found in the tail assembly gene cluster of certain caudate bacteriophages. CONCLUSION: These observations imply that members of the Ub family had already formed strong functional associations with E1-like proteins, UBC/E2-related proteins, and JAB peptidases in the bacteria. Several of these Ub-like proteins and the associated protein families are likely to function together in signaling systems just as in eukaryotes.
Six highly repeated DNA families were analyzed using Southern blotting and fluorescence in situ hybridization in a comparative study of 46 species of artiodactyls belonging to seven of the eight extant taxonomic families. Two of the repeats, the dispersed bovine-Pst family and the localized 1.715 component, were found to have the broadest taxonomic distributions, being present in all pecoran ruminants (Giraffidae, Cervidae, Antilocapridae, and Bovidae), indicating that these repeats may be 25-40 million years old. Different 1.715 restriction patterns were observed in different taxonomic families, indicating that independent concerted evolution events have homogenized different motifs in different lineages. The other four satellite arrays were restricted to the Bovini and sometimes to the related Boselaphini and Tragelaphini. Results reveal that among the two compound satellites studied, the two components of the 1.711a originated simultaneously, whereas the two components of the 1.711b originated at two different historical times, perhaps as many as 15 million years apart. Systematic conclusions support the monophyly of the infraorder Pecora, the monophyly of the subfamily Bovinae (containing the Boselaphini, Bovini, and Tragelaphini), an inability to resolve any interrelationships among the other tribes of bovids, paraphyly of the genus Bos with respect to Bison, and a lack of molecular variation among two morphologically and ecologically distinct subspecies of African buffaloes (Syncerus caffer cafer and S. c. nanus). Cytogenetically, a reduction in diploid chromosome numbers through centric fusion in derived karyotypes is accompanied by a loss of centromeric satellite DNA. The nilgai karyotype contains an apparent dicentric chromosome as evidenced by the sites of 1.715 hybridization. Telomeric sequences have been translocated to the centromeres without concomitant chromosomal rearrangement in Thompson's gazelle.
This paper presents systematic review findings to best summarize the assessment of oral health and the use of oral assessment tools by nurses and carers for adults with dementia living in residential aged care facilities. The systematic review searched electronic databases for articles in English (1980 to 2002) and supplemented these with a secondary search of references cited in articles meeting the review inclusion criteria. Delineation is needed between a comprehensive dental examination conducted by a qualified dentist and a dental assessment screening by a carer, nurse, allied health professional or medical practitioner. Dental examinations should be supplemented with oral health assessments and screenings by trained nurses and carers to monitor residents' oral health, evaluate oral hygiene care interventions, act as a trigger to call in a dentist when required, assist with residents' individualized oral hygiene care planning and assist with triaging and prioritization of residents' dental needs. To date, the most comprehensive, validated and reliable assessment screening tool for use by nurses and carers with cognitively impaired institutionalized residents is the Brief Oral Health Status Examination. Other less comprehensive oral assessment tools that are useful for nurses and carers of institutionalized dementia populations include the Index of Activities of Daily Oral Hygiene and the Mucosal Plaque Score. These review findings presented evidence to support the use of oral assessment screening tools by nurses and carers for cognitively impaired residents living in residential aged care facilities. Few validated and reliable tools have been published for use by carers in the cognitively impaired residential care population, and continued evolution of oral assessment screening tools needs to embrace the complete spectrum of residents' levels of cognitive impairment.
Superficial transitional cell carcinomas (TCC) of the urinary bladder have been shown to be monoclonal. However, no combined study of clonality and tumor suppressor genes (TSG) is available to date for muscle-invasive TCC. Forty-four muscle-invasive TCC of the urinary bladder selected from women were included in this study. Tumor cells located above and below the muscularis mucosa zone were systematically microdissected and used for DNA extraction. Hha-I digested and undigested samples were used to study the methylation pattern of androgen receptor alleles and undigested samples were used for microsatellite analysis of TSG (TP53, RB1, WT1, and NF1). Both loss of heterozygosity (LOH) and single nucleotide polymorphism (SNP) analyses were performed using optimized denaturing gradient gel electrophoresis. The expression of p53, pRB, and p21WAF1 was assessed by immunohistochemistry. Appropriate controls were run in every case. All except two TCC showed a monoclonal pattern with the same allele inactivated in both compartments. Microsatellite analysis of TSG revealed the same LOH/SNP pattern in both tumor compartments in 30 cases (involving more than 1 TSG locus in 8) and genetic heterogeneity in 14 cases. From the latter group, 9 cases expressed more genetic changes in the deep compartment (involving TP53 gene in all cases, WT1 gene in 2, and NF1 in 1), whereas in 4 cases the superficial compartment showed more genetic changes (three involving NF1 and one involving both RB and TP53). No statistical difference in the immunoexpression was detected, although it tended to be higher in the superficial compartment than in the deep compartment. These concordant data in polymorphic DNA regions indicate that bladder-muscle-invasive TCC are monoclonal proliferations with homogeneous tumor cell selection. Heterogeneous tumor cell selection by topography defined two different genetic compartments: superficial, NF1-defective, and deep, TP53-defective. No differences in the immunohistochemical expression were observed, precluding a more extensive clinical application.
Chemosensory systems play key roles in the survival and reproductive success of insects. Two large and diverse chemosensory gene families, odorant receptors (ORs) and odorant-binding proteins (OBPs), play critical roles in insect chemosensation and mediate odour-guided behaviours. In the process of insect chemosensation, odorants from the environment pass through pores in the antennal sensilla and become soluble in the sensillar lymph, either directly on contact or by binding to an OBP. Solubilized odour molecules diffuse through the lymph until they reach and activate their cognate ORs, sending electrophysiological signals to the insect brain. To better understand the evolutionary roles of OR and OBP gene families among members of the Heliothinae, we systematically characterized these two gene families in Chloridea virescens (Lepidoptera: Noctuidae). A total of 81 ORs and 49 OBPs were identified genome-wide. Based on the number and positions of conserved cysteine residues, the OBPs were classified into three types: 34 Classic OBPs, 8 Minus-C OBPs and 7 Plus-C OBPs. Phylogenetic analyses identified potential gene duplications and losses within OR and OBP gene families among members of the Heliothinae, which may be associated with differences in their volatile sensation and olfactory behaviours. Further motif and structural analyses identified a conserved region that was unique among pheromone receptors and predicted as key residues of the binding pocket, implying its critical role in pheromone detection. Future work should focus on experimentally validating its function. Overall, our findings provide important insights into how chemosensory gene evolution contributes to ecological adaptation and reproductive isolation in the Heliothine moths.