Coronary artery bypass grafting: how much does it cost?

OBJECTIVE: To calculate the cost of coronary artery bypass grafting (CABG) and to compare it with the costs determined in two previous Canadian studies. DESIGN: Retrospective cost-analysis study. SETTING: A tertiary care referral hospital. PATIENTS: Fifty patients who had undergone successful triple and quadruple CABG between Jan. 3 and 30, 1989. MAIN RESULTS: The cost of CABG per patient varied from $10,982 to $33,676 (mean $14,328) (in 1988 Canadian dollars). The cost tended to increase with age and number of vessels grafted. Compared with the patients in the two previous Canadian studies our patients were older, had more vessels grafted and cost more to treat, even after the total hospital costs were adjusted for inflation. CONCLUSIONS: The population undergoing CABG is changing: it is older and has more diseased vessels. These changes have had a significant impact on the cost of CABG. Further study is required to determine the outcome and benefit of CABG in this group of patients.     

Amazon vegetation: how much don’t we know and how much does it matter?

In spite of the existence of a vast body of information on the plant diversity of the Amazon, there remain significant obstacles to informed decision-making and management for conservation. Species distributions are poorly understood and the relationships between diversity and composition of vegetation, ecosystem services and resilience to climatic fluctuations are insufficiently clear. The geographic distribution of phylogenetic diversity in relation to current protected areas is unexplored and very little is known about intraspecific genetic variability and its practical significance. Interpretation of vegetation differentiation and distribution remains relatively simplistic; there are still large parts of the basin for which few or no botanical data exist, and many rare and sparsely distributed species remain undiscovered. Improved understanding of the ecological roles, dynamics and associations of the species of greatest importance for the maintenance of sustainable livelihoods and ecosystem services, habitat restoration and adaptation to climate change is a high priority. In many cases these are common and widespread species. Some of these issues are explored by looking at the Cristalino region in northern Mato Grosso as a case-study. Effective integration, quality assessment, synthesis and application of existing data on the plant diversity of the Amazon will help to address these issues. However, more targeted information is needed from the ground. Future prioritisation of research effort will require a careful and pragmatic balance between the ‘traditional’ focus on rare and endemic species and species-rich communities, and the growing need to understand the key ‘framework’ elements that will determine the future of the Amazon environment. Similar situations are faced elsewhere in the tropics: for botanical research institutes in the 21st century this demands an urgent re-evaluation of core activities and concerted engagement with the issues and challenges facing conservation in a context of rampant population growth, climate change and environmental destruction.     

Impact factor in cytopathology journals: what does it reflect and how much does it matter?

B. AbdullGaffar
Impact factor in cytopathology journals: what does it reflect and how much does it matter? Objective: To study the trends of impact factor (IF) in four cytopathology journals. To investigate the factors that might influence IF in cytopathology literature and whether IF has any impact on cytopathology practice. Methods: The IFs of four cytopathology journals were searched from 2005 to 2009. The IFs and their relationships with the types and number of publications, publishers, the official societies, readership, the quality of their contents, the topics covered and the levels of evidence were compared. Results: Cancer Cytopathology (CC) had the highest IF. Acta Cytologica (AC) had the lowest IF, which appeared to be in decline. Cytopathology (C) and Diagnostic Cytopathology (DC) had a slow but steady increase in their IF. Components that might influence these differences could include the category and the society of the journal, targeted readers and certain types of publications. Publishers, the number of publications, the types of topics covered and the levels of evidence probably have no major effect on IF. Conclusions: IF has its own benefits and original applications. IF is a quantitative measure that does not reflect the levels of evidence in cytopathology journals. IF should not be abandoned because it might encourage competition between cytopathology journals, but it should not dictate their contents.     

The evolution of noncoding DNA: how much junk, how much func?

Comparative sequence analysis on a genomic scale has opened the door for the systematic analysis of cis-acting regulatory DNA. It is now possible to begin to answer basic questions such as, how much meaningful noncoding sequence is in the genome? How strong is natural selection on functional noncoding sequences in different species? Two recent articles have capitalized on the comparative genomic approach in an attempt to answer these questions with surprising results.     

Integration of omics data: how well does it work for bacteria?

In the current omics era, innovative high-throughput technologies allow measuring temporal and conditional changes at various cellular levels. Although individual analysis of each of these omics data undoubtedly results into interesting findings, it is only by integrating them that gaining a global insight into cellular behaviour can be aimed at. A systems approach thus is predicated on data integration. However, because of the complexity of biological systems and the specificities of the data-generating technologies (noisiness, heterogeneity, etc.), integrating omics data in an attempt to reconstruct signalling networks is not trivial. Developing its methodologies constitutes a major research challenge. Besides for their intrinsic value towards health care, environment and industry, prokaryotes are ideal model systems to further develop these methods because of their lower regulatory complexity compared with eukaryotes, and the ease with which they can be manipulated. Several successful examples outlined in this review already show the potential of the systems approach for both fundamental and industrial applications, which would be time-consuming or impossible to develop solely through traditional reductionist approaches.     

Screening for hypercholesterolemia among Canadians: how much will it cost?

OBJECTIVE: To determine the cost of screening all Canadians aged 30 years or more without coronary heart disease (CHD) for hypercholesterolemia. DATA SOURCES: The expected results of initial screening of the serum cholesterol level were estimated on the basis of 1986 Canadian census data and the 1978 Canada Health Survey. The results of repeat testing were estimated on the basis of data from the Lipid Research Clinics Prevalence Study. Lipid profile results were extrapolated from tests at the Montreal General Hospital''s clinical chemistry laboratory. Laboratory costs and primary care practitioner costs were provided by the Canadian Society of Clinical Chemists and provincial fee schedules respectively. MAIN RESULTS: Among 12,479,356 Canadians free of CHD 48.7% would be identified as being at high risk, 4.8% would be identified as being at moderate risk, and 46.6% would be reassured that their lipid risk for CHD was low. The total cost of implementing the program in the first year would be $432 million to $561 million ($325 million for laboratory tests and $107 million to $236 million for visits to primary care practitioners). CONCLUSION: The substantial cost of implementing a nationwide screening program must be weighed against the expected benefits to ensure that the final result is both practical and economically feasible.     

Ring cleavage of sulfur heterocycles: how does it happen?

Sulfur heterocycles are common constituents of petroleum and liquids derived from coal, and they are found in some secondary metabolites of microorganisms and plants. They exist primarily as saturated rings and thiophenes. There are two major objectives driving investigations of the microbial metabolism of organosulfur compounds. One is the quest to develop a process for biodesulfurization of fossil fuels, and the other is to understand the fates of organosulfur compounds in petroleum- or creosote-contaminated environments which is important in assessing bioremediation processes. For these processes to be successful, cleavage of different types of sulfur heterocyclic rings is paramount. This paper reviews the evidence for microbial ring cleavage of a variety of organosulfur compounds and discusses the few well-studied cases which have shown that the C-S bond is most susceptible to breakage leading to disruption of the ring. In most cases, the introduction of one or more oxygen atom(s) onto the adjacent C atom and/or onto the S atom weakens the C-S bond, facilitating its cleavage. Although much is known about the thiophene ring cleavage in dibenzothiophene, there is still a great deal to be learned about the cleavage of other sulfur heterocycles.     

Patterns of endemism in African birds: how much does taxonomy matter?

It has been suggested that the 'right' biogeographic patterns will only arise with a species concept reflecting the finest splitting of terminal phylogenetic branches. The significance of taxonomic resolution was assessed using distributional data for all resident African land-birds, held at the Zoological Museum of Copenhagen. The primary database (in a one-degree geographical grid) served as a template for creating two new databases: one, where the distributional records were allocated to species according to the 'Speciation Atlases' for African birds (Hall and Moreau 1970, Snow 1978) and two, according to the finest taxonomic splitting that has since then been suggested in the literature. With this spatial resolution, the species richness pattern is almost exactly the same whether old or new taxonomy is used. The endemism follows another pattern with marked local aggregates. The location of principal aggregates are quite robust to recent splitting, although a slightly more complex structure appears. Also some small new areas of endemism emerge, each with 2–3 narrow endemics. However, large portions of African savannah and lowland rainforest are still characterised by a total lack of narrow endemism. Based on the current understanding of diversification processes and adaptive re-distribution it is suggested that the uneven distribution of narrowly endemic and widespread species will persist even if it were possible, in the future, to define terminal taxa in a consistent way.     

The non‐existent aging program: how does it work?

Summary Aging and lifespan determination have been viewed, in the most well-accepted theories, as nonprogrammatic, and are thought to result from the evolutionary selection for early fitness at the expense of late survival. Here, recent data implicating potentially programmatic aspects of aging and lifespan determination are discussed, and analogies between programmed cell death and programmed organismal death are offered. It is hoped that the recognition of at least the possibility of a programmatic aspect, or aspects, to the determination of longevity and the process of aging will help to optimize our chances to identify appropriate therapeutic targets both for longevity enhancement and disease prevention.     

Treatment of COVID-19 with MSCs: how does it work?

Science China Life Sciences -     

The shape of life: how much is written in stone?

Considering the enormous diversity of living organisms, representing mostly untapped resources for studying ecological, ontogenetic and phylogenetic patterns and processes, why should evolutionary biologists concern themselves with the remains of animals and plants that died out tens or even hundreds of millions of years ago? The reason is that important new insights into some of the most vexing evolutionary questions are being revealed at the interfaces of palaeontology, developmental biology and molecular biology. Attempts to synthesise information from these disciplines, however, often encounter their greatest hurdles in considerations of the radiation of the Metazoa. Ongoing challenges relate to the origins of body plans, the relationships of the metazoan phyla and the timing of major evolutionary radiations. Palaeontology not only has its own unique contributions to the study of evolutionary processes, but provides a lynchpin for many of the emerging techniques.     

Fragmentation of clones: how does it influence dispersal and competitive ability?

We applied individual-based simulations to study the effect of physiological integration among ramets in clonal species that live in patchy habitats. Three strategies were compared: (1) Splitter, in which the genet was fragmented into independent ramets; (2) Transient Integrator, where only groups of ramets were connected; and (3) Permanent Integrator, in which fragmentation did not occur, and the whole genet was integrated. We studied the dynamics of spatial spreading and population growth in these strategies separately and in competition. Various habitat types were modeled by changing the density of favorable habitat patches. We found that the spatial pattern of good patches significantly influenced the growth of the populations. When the resource patches were scarce, a large proportion of the carrying capacity of the habitat was not utilized by any of the strategies. It was the Splitter that proved to be the most severely dispersal-limited. But at the same time, it could compete for the good patches most efficiently. The balance between these two contradictory effects was largely determined by the proportion of favorable to unfavorable areas. When this proportion was low or intermediate (up to ca. 50% good), integration was more advantageous. At higher proportions, fragmentation became beneficial. Fragmentation into groups of ramets (Transient Integration) was not sufficient, only radical splitting could ensure a significant selective advantage. Transient Integrators got fragmented according to the spatial pattern of ramet mortality. It was interesting that the enrichment of the area in good sites did not lead to larger fragment sizes. It merely raised the number of fragments. Nevertheless, these small fragments were more similar to integrated genets (in the Permanent Integrator) than to solitary ramets (in the Splitter) in terms of dispersal and competitive ability. This suggests that even a slightly integrated clonal species can be ecologically considered as an integrator.     

The evolution of large size: how does Cope's Rule work?

Cope's Rule is the tendency for organisms in evolving lineages to increase in size over time. The concept is detailed in many textbooks, but has rarely been demonstrated. Many suggestions of the benefits of large body size exist, but none has yet been confirmed empirically. Using a large-scale analysis of recent studies, Kingsolver and Pfennig have now shown how size benefits survival, mating success and fecundity, and they provide convincing arguments for a mechanism that is capable of driving Cope's Rule.     

The posttranslational concept of protein folding: how valid is it?

Two concepts of protein folding are known. One of them, the cotranslational concept, states that a protein folds during the synthesis of the polypeptide chain on the ribosome. According to the other, the posttranslational concept, the protein starts to fold just after the synthesis of its polypeptide chain. This article attempts to show that the posttranslational concept is hardly suited to solve the problem of protein folding. In our opinion, polypeptide chains cannot be represented as random coils. They are stiff chain-like macromolecules rather than flexible ones: the single bond rotational barriers of a polypeptide substantially exceed the accepted standard values; even in strong denaturing conditions, a protein possesses a considerable amount of residual folded structures. We believe that the popular "hierarchical" models for the protein folding mechanism are not realistic because the formation of secondary and tertiary structures of proteins occurs simultaneously and cooperatively. The time for the elongation of a polypeptide chain by one amino acid residue during biosynthesis exceeds considerably the time of the formation of alpha-helices and beta-sheets in proteins as well as the time supposed for the spatial structure formation of a native protein during renaturation. Thus, we believe that the mechanism of protein folding in vivo cannot be clarified by denaturation-renaturation experiments. In our opinion, the phenomenon of protein renaturation is no more than the restoration of native protein conformation (which initially forms cotranslationally) disrupted during denaturation, and thus denaturation-renaturation experiments cannot serve as a model to clarify the mechanism of protein folding.     

The evolution of the neocortex in mammals: how is phenotypic diversity generated?

Evolution of the mammalian neocortex is difficult to examine directly. For this reason, comparative studies and developmental studies are the best way of gaining insight into the evolutionary process. Comparative studies indicate that neocortical evolution is constrained, and that the types of systems-level modifications made to the neocortex are limited. Developmental studies of gene expression suggest that genetic contingencies set up aspects of cortical organization and connectivity, and that the complex spatial and temporal interactions of genes constrain development and evolution. Although genes obviously contribute to phenotypic variability, variability can also be achieved through alterations in the sensory receptor arrays, or changes in sensory driven activity. The intracellular mechanisms that enable phenotypic variability might evolve, but often the phenotypic characteristic in question is context-dependent.     

Insect diversity of a Costa Rican dry forest: why keep it,and how?

The dry forest of the 108 km2 Santa Rosa National Park in northwestern Costa Rica contains as many as 13 000 species of insects (including 3140 species of moths and butterflies) sustained by and sustaining about 700 species of plants and 400 species of vertebrates. These insects require explicit conservation attention. They are more than just decorations on the plants; rather, they are the building blocks and glue for much of the habitat. They are the food for much of the carnivore community, and the insect species are not merely interchangeable bits of nutrients. They are major killers of seeds, and thereby influence both the plant species composition of a habitat and prevent the better competitors from taking it over. They are the primary pollinators and are specific enough to be neither interchangeable nor replaceable with other animals; the seeds resulting from their pollination activities are major animal foods in the habitat. They are a diverse, puzzling, complex, intrinsically attractive, and major part of the intellectual display offered by tropical wildlands, the display that will be the eventual foundation for most of the reason why tropical wildlands will be retained as such in the future.
The retention and maintenance of insect species richness in a tropical wildland is strongly rooted in the preservation of plant species richness, in maintaining habitat mosaics (different members of which are used by a given insect in different seasons), in preserving a large diversity of habitats, and in recognizing the threat posed by insect crop associates in nearby agricultural lands.