Biomedical research in Revista de Biologia Tropical

The contributions published in Revista de Biología Tropical in the area of Biomedical Sciences are reviewed in terms of number of contributions and scope of research subjects. Biomedical Sciences, particularly Parasitology and Microbiology, constituted the predominant subject in the Revista during the first decade, reflecting the intense research environment at the School of Microbiology of the University of Costa Rica and at Hospital San Juan de Dios. The relative weight of Biomedicine in the following decades diminished, due to the outstanding increment in publications in Biological Sciences; however, the absolute number of contributions in Biomedical Sciences remained constant throughout the last decades, with around 80 contributions per decade. In spite of the predominance of Parasitology as the main biomedical subject, the last decades have witnessed the emergence of new areas of interest in the Revista, such as Pharmacology of natural products, Toxinology, especially related to snake venoms, and Human Genetics. This retrospective analysis evidences that Biomedical Sciences, particularly those related to Tropical Medicine, were a fundamental component during the first years of Revista de Biología Tropical, and have maintained a significant presence in the scientific output of this journal, the most relevant scientific publication in biological sciences in Central America.     

An improved basal medium for Y-1 mouse adrenal cortex tumor cells in culture

Summary Y-1 cells were passaged weekly for 6 wk in MACT IV medium without a period of adaptation to this basal medium that requires 1% dialyzed fetal bovine serum as a supplement. The steroid pathway and chromosome number, reported earlier for this cell line under culture conditions that used much higher concentrations of nondialyzed sera, remained stable despite dialysis and reduction of the fetal bovine serum to 1%. Mass spectral analyses were carried out at the Mass Spectrometric Facility for Biomedical Research, Department of Biochemistry, Faculty of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, supported by NIH Grant RR-00273. This research was supported by the Medical Research Service of the Veterans Administration.     

芍药苷对结肠癌SW480细胞增殖、侵袭、迁移的影响

目的观察芍药苷对人结肠癌SW480细胞株增殖、侵袭、迁移的影响,探究其干预机制。方法含10%胎牛血清的DMEM/F12培养基常规培养人结肠癌SW480细胞株,CCK-8以及EdU-488法检测芍药苷对SW480细胞增殖的影响,Transwell小室检测芍药苷对SW480细胞侵袭、迁移的影响,Westernblot法检测beclin1、Bcl-2蛋白的表达。结果不同浓度芍药苷分别处理24h、48h、72h的结肠癌SW480细胞增殖活性受到显著抑制:相比较对照组,160μg/ml芍药苷处理48h后,SW480细胞内黄绿色荧光减弱,细胞增殖率显著下降,为(58.91±4.99)%;SW480细胞的侵袭细胞数、迁移细胞数显著下降:侵袭抑制率为26.50%,迁移抑制率为24.67%;beclin1蛋白表达高于对照组,Bcl-2蛋白表达低于对照组,beclin1与Bcl-2蛋白表达呈负相关。结论芍药苷能够抑制结肠癌SW480细胞增殖、侵袭和迁移,其机制可能通过抑制Bcl-2蛋白表达,上调beclin1蛋白的表达。     

Simulation results with stepwise mutation model and their interpretations

Summary Monte Carlo simulations are performed to compare the predictions based on the two presently used theoretical models for studying genetic variations in natural populations, the infinite allele model and the stepwise mutation model. Distribution of heterozygosity is noticed to be similar under these models until the product of population size and mutation rate is large. It is seen that electromorphs with high population frequency usually contain older alleles (at the codon level) than an electromorph of low population frequency. The interpretations of these results in explaining the allelic variations at electrophoretic level is also discussed.Research supported by U.S. Public Health Service General Research Support Grant 5 SO 5 RR 07148 from the University of Texas Health Science Center, Graduate School of Biomedical Sciences, Houston, Texas     

光学相干层析术高分辨率活体成像泼尼松龙诱导的骨质疏松斑马鱼模型

本研究利用光学相干层析术OCT对泼尼松龙诱导的斑马鱼骨质疏松模型进行活体成像,并结合电镜能谱技术定量分析斑马鱼模型骨质的钙磷元素含量及分布情况,共同探讨OCT方法在基于斑马鱼模型开展的骨质疏松研究中的使用价值。选取40条3月龄野生型斑马鱼暴露于50μmol/L泼尼松龙溶液和含0. 5%DMSO的溶液中(对照组),28. 5℃下培养,分别于第5、10、20天取出浸药组和对照组进行OCT活体成像,比较两者光散射特征。在每个时间点的成像之后,将浸药组的5条斑马鱼处死,然后取颅骨进行元素含量电镜扫描能谱分析。本研究利用50μmol/L泼尼松龙溶液培养斑马鱼至第20天,成功构建了斑马鱼骨质疏松模型。与对照组相比,模型组活体OCT成像显示骨组织光散射减弱,光子量明显减少,呈不均匀分布。能谱元素检查结果说明颅骨内所含钙、磷比例明显下降,证实骨质疏松发生,骨量减少。OCT成像方法在对斑马鱼骨质疏松模型进行活体、实时、无创等研究方面具有重要价值,本试验也为骨质疏松疾病的研究和药物筛选等方面提供了新的有效的方法。     

Peak drug levels in linear pharmacokinetic systems—II. Conditions for a paradoxical injection rate effect with rectangular input

The preceding paper (Thorn, 1981) has shown that in a linear pharmacokinetic system with a multimodal impulse response the peak drug level may sometimes be smaller with slower rates of injection. This paper presents two theorems on this paradoxical injection rate effect where the injection is a constant infusion of finite duration. The first theorem establishes a graphical method for determining whether a given impulse response will give a paradoxical injection rate effect; and the second establishes that the maximum paradoxical increase in peak drug level is by a factor of two. It is further shown that in order to approach this maximum paradoxical increase the impulse response must contain two isolated, sharp, narrow pulses of approximately equal area. Some examples of bimodal arterial dye-dilution curves from the literature are discussed as impulse responses; and there is also a discussion of the behavior of drug level maxima and minima at different injection rates. This work was supported in part by U.S. Public Health Service Research Grant GM 21269 from the National Institute of General Medical Sciences, and in part by Biomedical Research Support Grant S07 RR 05932 from the National Institutes of Health. A portion of this work was presented at the Annual Meeting of the Society for Mathematical Biology at the Medical School of the University of Pennsylvania, Philadelphia, August 1976.     

Peak drug levels in linear pharmacokinetic systems—III. Multimodal impulse responses in multicompartment systems

This paper deals with the unimodality of the ‘impulse response’ in compartmental systems, where the ‘impulse response’ in any given compartment is the time course of the amount of diffusing substance in that compartment after an initial instantaneous injection of the substance into that or some other compartment. It is shown that in certain compartmental structures, with injection in certain compartments, the impulse response is always unimodal or monotonic in all compartments, regardless of the numerical values of the various transfer rate coefficients. Structures with this property are here named ‘UM structures’, and they include the familiar mammillary and catenary structures. In this paper, the set of all UM structures is described. Structures which are not UM (NUM structures) are identified by showing that, by removal of certain connections and compartments according to certain rules, they can be reduced to small structures which can be shown to be NUM by numerical computation. Computations on two systems with bimodal impulse responses show that with constant infusions of a fixed amount of substance the peak level may increase paradoxically with decrease in the infusion rate over a certain range. This effect is extremely small, however. Supported in part by U.S. Public Health Service Research Grant GM 21269 from the National Institute of General Medical Sciences, and in part by Biomedical Research Support Grant S07 RR 05392 from the National Institutes of Health.     

Report on the 1st International Conference of the Hellenic Proteomics Society in Athens, Greece

The First International Conference of the Hellenic Proteomics Society took place at the Foundation for Biomedical Research of the Academy of Athens, Athens, Greece, 22-25 May 2005. Scientists from about 20 countries attended this conference where proceedings in proteomics methodologies, advances in mass spectrometry, proteomics applications, disease diagnostics and bioinformatics were presented. The relatively small size of the meeting gave the opportunity for the attendees to interact and discuss projects and collaborations. The event was completely financed by companies which exhibited their products and services related to proteomics research.     

BOOK REVIEWS

Book Reviews in this Article:
The Uses of Philosophy , by Mary Warnock
Issues in Reproductive Technology , by Helen Bequaert Holmes (ed)
Life Before Birth: The Moral and Legal Status of Embryos and Fetuses , by Bonnie Steinbock
The Ethics of Diagnosis , edited by Jose Luis Peset and Diego Gracia.
Gene Mapping: Using Law and Ethics as Guides , edited by George J. Annas and Sherman Elias.
Creation and Abortion: A Study in Moral and Legal Philosophy , by F.M. Kamm.
Wonderwoman and Superman: The Ethics of Human Biotechnology , by John Harris
International Ethical Guidelines for Biomedical Research Involving Human Subjects , by Council for International Organizations of Medical Sciences (CIOMS)     

Using online lectures to make time for active learning

To make time in class for group activities devoted to critical thinking, we integrated a series of short online lectures into the homework assignments of a large, introductory biology course at a research university. The majority of students viewed the online lectures before coming to class and reported that the online lectures helped them to complete the in-class activity and did not increase the amount of time they devoted to the course. In addition, students who viewed the online lecture performed better on clicker questions designed to test lower-order cognitive skills. The in-class activities then gave the students practice analyzing the information in groups and provided the instructor with feedback about the students' understanding of the material. On the basis of the results of this study, we support creating hybrid course models that allow students to learn the fundamental information outside of class time, thereby creating time during the class period to be dedicated toward the conceptual understanding of the material.     

Neural control of RNA synthesis in regenerating limbs of the adult newtTriturus viridescens

Summary Polyacrylamide gel electrophoresis was used to investigate the role of nerves in controlling patterns of RNA synthesis in regenerating limbs of the adult newt,Triturus viridescens. Denervation has the same effect on nerve-dependent and independent stages of regeneration, reducing by approximately 40–50% the synthesis of ribosomal and transfer RNA. Although a differential qualitative response of messenger RNA synthesis to denervation between nerve-dependent and independent stages has not been ruled out, the results would indicate that the effect of the nerve on RNA metabolism in individual blastema cells is the same over the whole process of regeneration. Since the one constant effect of denervation on regeneration is to inhibit regenerate growth in volume, the emancipation of blastemal morphogenetic activity from nerve requirements is more likely to be a function of attaining a critical mass of blastema cells, rather than a change in the metabolic response of blastema cells to the nerve.Research supported by a Biomedical Sciences Grant from the School of Life Sciences, University of Illinois, to D.L.S.     

Alternative consent models for biobanks: the new Spanish law on biomedical research

This article provides an overview of recent contributions to the debate on the ethical use of previously collected biobank samples, as well as a country report about how this issue has been regulated in Spain by means of the new Biomedical Research Act, enacted in the summer of 2007. By contrasting the Spanish legal situation with the wider discourse of international bioethics, we identify and discuss a general trend moving from the traditional requirements of informed consent towards new models more favourable to research in a post-genomic context.     

Allozyme and mitochondrial DNA analysis of a hybrid zone between white-tailed deer and mule deer (Odocoileus) in west texas

Thirty allozyme loci and 35 mitochondrial DNA (mtDNA) restriction sites were examined in 24 white-tailed deer and 46 mule deer from a hybrid zone in West Texas. A common mtDNA genotype is shared by all of the mule deer with 67% of the white-tailed deer. At the albumin locus, 13% of the white-tailed deer and 24% of the mule deer are heterozygous, sharing alleles that are otherwise species-specific in allopatric populations; 7% of the mule deer are homozygous for the allele that is characteristic of allopatric white-tailed deer. Gene flow appears to have been bidirectional, with greater genetic introgression into mule deer. The mtDNA data suggest that matings between white-tailed and mule deer have occurred in the past. Despite evidence of genetic introgression, analysis of multilocus genotypes indicates that none of the deer examined is an F₁ hybrid. Production of such hybrids appears to be generally uncommon in North American deer; management plans that assume otherwise should be reconsidered.This work was supported by an NIH Biomedical Research Support Grant, Texas Agricultural Experiment Station Program Development and Expanded Research Awards, the Caesar Kleberg Research Program in Wildlife Ecology, and a Natural Sciences and Engineering Research Council Operating Grant.     

Peak drug levels in linear pharmacokinetic systems—I. Effect of rate of injection

This paper presents three theorems on the peak drug levels that result from injection into a linear pharmacokinetic system. As a preliminary, the “rate of injection” is defined in terms of time expansion or time contraction of the injection function (input). The first theorem then states that the peak drug level will not be greater when the rate of injection is slow than when it is fast, if the impulse response is unimodal. The second theorem sets limits for the time of the maximum drug level, in relation to the time of the maximum of the (unimodal) impulse response and the duration of the input. The third theorem defines conditions which assure a definitely lower peak drug level if the rate of injection is slower. A graphical method is suggested for determining the times and magnitudes of the peak drug levels that result from constant infusions of a fixed dose at different rates. An example is provided to show that if the impulse response is multimodal then the peak drug level may sometimes increase with a decrease in the injection rate. Supported in part by U.S. Public Health Service Research Grant GM 21269 from the National Institute of General Medical Sciences, and in part by Biomedical Research Support Grant S07 RR 05392 from the National Institutes of Health. A portion of this work was presented at the Annual Meeting of the Society for Mathematical Biology at the Medical School of the University of Pennsylvania, Philadelphia, August 1976.     

Predator-prey systems with group defence: The paradox of enrichment revisited

The main concern of this paper is with survival or extinction of predators in models of predator-prey systems exhibiting group defence of the prey. It is shown that if there is no mutual interference among predators, enrichment could result in their extinction. However, if there is mutual interference, the predator population survives (at least deterministically). Research partially supported by the Natural Sciences and Engineering Research Council of Canada, Grant No. NSERC A 4823. Research partially supported by a Natural Sciences and Engineering Research Council of Canada postdoctoral fellowship.     

Science attitudes and knowledge among preclinical medical students in Pokhara, Nepal

Knowledge of science and the scientific method are important in learning about and using evidence-based medicine in practice. Courses in research methodology have been introduced for both medical students and practicing doctors. In Pokhara, the basic science subjects are taught in an integrated manner during the first four semesters of the undergraduate medical course. Studies on students' attitudes towards and knowledge of science are lacking in medical colleges in Nepal. Hence the study was carried out to obtain information on students' attitude towards and knowledge of science and scientific methodology among preclinical medical students and note the association, if any, of students' attitudes and their demographic characteristics. The study was carried out in March 2005 among the students of the first four semesters at the Manipal College of Medical Sciences, Pokhara, Nepal using a questionnaire developed by Hren and coworkers. Two hundred and twenty students (overall response rate 73.3%) successfully completed the questionnaire. Seventy-five respondents were Nepalese, 115 were Indians, 27 were Sri Lankans and 3 belonged to other nationalities. The X +/- SD total attitude score was 147.4 +/- 10.8 (neutral score 135). The X +/- SD scores on the subscales, value of science to humanity, value of scientific methodology and value of science to medicine were 51.3 +/- 5.4, 39.6 +/- 3.7 and 58.5 +/- 5.9 (neutral scores were 36, 51 and 48 respectively). The knowledge score measured using a set of 8 multiple choice questions was 3.3 +/- 1.4. The attitude scores were lower and the knowledge score was comparable to that reported previously in a study in Croatia but higher than that reported from Southeast Europe.     

A miniature respiratory minute volume sensor for the flight environment

A miniature respiratory rate and volume sensor has been developed and flight qualified at the Flight Research Center. This device weighs only 172 grams, is sufficiently rugged to perform in the flight environment, and small enough to be worn as an integral part of the pilot's personal equipment. The safe operation of this system in an hyperbaric, pure oxygen atmosphere, is demonstrated. Details for the fabrication of the system are described. Operational experience over a two year period is reported.Dr. Lewis is presently a fellow in aerospace medicine at the Lovelace Foundation for Medical Education and Research, Albuquerque, N.M., 87108. Work reported here was completed while he was Director of Biomedical Programs at the NASA Flight Research Center. Reprint requests should be directed there.     

Cells in experimental life sciences - challenges and solution to the rapid evolution of knowledge

Cell cultures used in biomedical experiments come in the form of both sample biopsy primary cells, and maintainable immortalised cell lineages. The rise of bioinformatics and high-throughput technologies has led us to the requirement of ontology representation of cell types and cell lines. The Cell Ontology (CL) and Cell Line Ontology (CLO) have long been established as reference ontologies in the OBO framework. We have compiled a series of the challenges and the proposals of solutions in this CELLS (Cells in ExperimentaL Life Sciences) thematic series that cover the grounds of standing issues and the directions, which were discussed in the First International Workshop on CELLS at the the International Conference on Biomedical Ontology (ICBO). This workshop focused on the extension of the current CL and CLO to cover a wider set of biological questions and challenges needing semantic infrastructure for information modeling. We discussed data-driven use cases that leverage linkage of CL, CLO and other bio-ontologies. This is an established approach in data-driven ontologies such as the Experimental Factor Ontology (EFO), and the Ontology for Biomedical Investigation (OBI). The First International Workshop on CELLS at the International Conference on Biomedical Ontology has brought together experimental biologists and biomedical ontologists to discuss solutions to organizing and representing the rapidly evolving knowledge gained from experimental cells. The workshop has successfully identified the areas of challenge, and the gap in connecting the two domains of knowledge. The outcome of this workshop yielded practical implementation plans to filled in this gap.This CELLS workshop also provided a venue for panel discussions of innovative solutions as well as challenges in the development and applications of biomedical ontologies to represent and analyze experimental cell data.     

The nonexistence of “hermaphoroditic” tracer systems

This communiction argues that so-called “hermaphroditic” tracer systems, which are neither open nor closed, do not exist physically. The argument is based on the assumption that any observable (possibly nonhomogeneous) macroscopic compartment can be approximated by a compartmentC with a finite number of entry points for the tracer, each associated with an abstract subcompartment ofC. It is shown that the “hermaphroditic” property requires that the mean waiting time be infinite in at least one of the subcompartments, or in a subcompartment elsewhere in the system. A subcompartment with infinite mean waiting time must have some sort of memory, of infinite duration, which knows how long a given particle has been retained, however long that is, and thereby determines its probability of departure. Assuming, as seems likely, that no physical basis exists for such an infinite memory, it follows that “hermaphroditic” systems do not exist. Supported in part by U.S. Public Health Service Research Grant GM 21269 from the National Institute of General Medical Sciences, and in part by Biomedical Research Support Grant S07 RR 05392 from the National Institutes of Health.     

RobertP Vertes and RobertW Stackman Jr: Electrophysiological Recording Techniques Springer Protocols, Neuromethods Series Nr. 54

This article is a review of the book: 'Biomedical Image Processing', by Thomas M. Deserno, which is published by Springer-Verlag. Salient information that will be useful to decide whether the book is relevant to topics of interest to the reader, and whether it might be suitable as a course textbook, are presented in the review. This includes information about the book details, a summary, the suitability of the text in course and research work, the framework of the book, its specific content, and conclusions.