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PubMedDate not supplied

The ascidian dihydropyridine-resistant calcium channel as the prototype of chordate L-type calcium channel.

This review describes recent findings on voltage-gated Ca channel (Cav channel) cloned from ascidians, the most primitive chordates. Ascidian L-type like Cav channel has several unusual features: (1). it is closely related to the prototype of chordate L-type Cav channels by sequence alignment; (2). it is resistant to dihydropyridine due to single amino acid change in the pore region, and (3). maternally provided RNA putatively encodes a truncated protein which has remarkable suppressive effect on Cav channel expression during development. Ascidian Cav channel will provide a useful molecular clue in the future to understand Ca(2+)-regulated cell differentiation and physiology with the background of recently defined ascidian genome and molecular biological tools.

Amino Acid Sequence↗

PubMed1985

Calcium channel modulators and calcium channels.

In recent years calcium has become recognized as an important 'second messenger', in that an increase in free intracellular calcium ion concentration is involved in many aspects of cellular activation. In excitable cells such as smooth muscle or cardiac tissue an influx of extracellular calcium ions through voltage sensitive calcium channels plays a major role in increasing the cytoplasmic free calcium concentration. It is now known that the activity of these calcium channels may be inhibited or stimulated by a range of ions, toxins and drugs. This article outlines the biochemistry and pharmacology of these 'calcium modulators', and discusses their present and future role as both biological tools, and as potent and selective drugs.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed2005

Using a battery of bioassays, benthic phytoplankton and the AUSRIVAS method to monitor long-term coal tar contaminated sediment in the Cache la Poudre River, Colorado.

This survey provides information on sediment toxicity and structural characteristics of the macroinvertebrates and benthic phytoplankton at 10 locations in the Cache la Poudre River after long-term exposure to coal tar residue. The application of the Australian river bioassessment system (AUSRIVAS) as well as a biotest battery was used to evaluate the river 'health' condition. Coal tar is a dense nonaqueous-phase liquid of significant environmental concern due to its toxicity and persistence in the subsurface. Organisms like Selenastrum capricornutum, Daphnia magna and Chironomus tentans, representing different complexities in the biosphere, were selected as test systems for ecotoxicological studies. The results obtained in this study indicate that a biotest battery, macroinvertebrate and benthic phytoplankton communities are in principle suitable biological tools for evaluation of toxic oil and coal-derived substances in long-term contaminated river sediment.

Animals↗

PubMed1996

Molecular biology of human oral cancer.

The application of molecular biological tools to the study of cancer has significantly advanced the field of human cancer research. Such study has demonstrated the involvement of two classes of highly conserved cellular genes in the malignant transformation process: oncogenes and tumor suppressor genes. Despite these advances in the molecular biology of human cancers, our understanding of human oral cancer lags behind that of cancer of other body sites. This review attempts to assess the current status of the molecular biology of human oral cancer.

Cell Adhesion Molecules↗

PubMed2006

Axopodial degradation in the heliozoon Raphidiophrys contractilis: a novel bioassay system for detecting heavy metal toxicity in an aquatic environment.

We observed the physiological effects of zinc, lead, mercury, copper, cadmium, and arsenic on the axopodia of the centrohelid heliozoon Raphidiophrys contractilis. In the presence of these heavy metal ions, the axopodial length of the heliozoon decreased in a concentration-dependent manner. When the heavy metal ions were examined at the same concentration, mercury produced the strongest effect on axopodia. At a high concentration (> 10-3 M) of any of the heavy metal ions examined, axopodia disappeared and cells became disrupted. Axopodia were also degraded by the addition of solutions with an acidic (< or = 6) or basic (> or = 8) pH. These observations indicate the toxic effects of heavy metal ions and non-neutral pHs on axopodial length, and also signify that R. contractilis can be used as an effective biological tool for the study of metal poisoning in eukaryotic cells.

Animals↗

PubMed2005

Toxicogenomics concepts and applications to study hepatic effects of food additives and chemicals.

Transcriptomics, proteomics and metabolomics are genomics technologies with great potential in toxicological sciences. Toxicogenomics involves the integration of conventional toxicological examinations with gene, protein or metabolite expression profiles. An overview together with selected examples of the possibilities of genomics in toxicology is given. The expectations raised by toxicogenomics are earlier and more sensitive detection of toxicity. Furthermore, toxicogenomics will provide a better understanding of the mechanism of toxicity and may facilitate the prediction of toxicity of unknown compounds. Mechanism-based markers of toxicity can be discovered and improved interspecies and in vitro-in vivo extrapolations will drive model developments in toxicology. Toxicological assessment of chemical mixtures will benefit from the new molecular biological tools. In our laboratory, toxicogenomics is predominantly applied for elucidation of mechanisms of action and discovery of novel pathway-supported mechanism-based markers of liver toxicity. In addition, we aim to integrate transcriptome, proteome and metabolome data, supported by bioinformatics to develop a systems biology approach for toxicology. Transcriptomics and proteomics studies on bromobenzene-mediated hepatotoxicity in the rat are discussed. Finally, an example is shown in which gene expression profiling together with conventional biochemistry led to the discovery of novel markers for the hepatic effects of the food additives butylated hydroxytoluene, curcumin, propyl gallate and thiabendazole.

Animals↗

PubMed2000

Nitric oxide synthase in atherosclerosis and vascular injury: insights from experimental gene therapy.

Gene therapy aims to intervene in a disease process by transfer and expression of specific genes in a target tissue or organ. Cardiovascular gene therapy in humans remains in its infancy, but in the last decade, experimental gene transfer has emerged as a powerful biological tool to investigate the function of specific genes in vascular disease pathobiology. Nitric oxide synthases, the enzymes that produce nitric oxide, have received considerable attention as potential candidates for vascular gene therapy because nitric oxide has pleiotropic antiatherogenic actions in the vessel wall, and abnormalities in nitric oxide biology are apparent very early in the atherogenic process. In this article, we review the use of nitric oxide synthases in experimental vascular gene therapy and assess the utility of these approaches for investigating the role of nitric oxide in atherosclerosis and their potential for human gene therapy.

Animals↗

PubMed2001

The Tol2 transposable element of the medaka fish: an active DNA-based element naturally occurring in a vertebrate genome.

Several DNA-based transposable elements are known to be present in vertebrate genomes, but few of them have been demonstrated to be active. The Tol2 element of the medaka fish is one such element and, therefore, is potentially useful for developing a gene tagging system and other molecular biological tools applicable to vertebrates. Towards this goal, analyses of the element at the molecular, cellular and population levels are in progress. Results so far obtained are described here.

Animals↗

PubMed2006

Affinity-based assay of Rho guanosine triphosphatase activation.

The recognition that Rho guanosine triphosphatases (GTPases) (Rho, Rac, and Cdc42) play important regulatory roles in many areas of cell biology has made the ability to measure their activity in cells an important biological tool. Because Rho GTPases become activated by conversion from guanosine diphosphate-bound states to guanosine triphosphate (GTP)-bound forms, affinity-based methods to detect the formation of GTP-Rho GTPases have been developed and are widely used for the purpose of assessing Rho GTPase activities in biological studies.

Apoptosis Regulatory Proteins↗

PubMed2003

Effect-directed analysis: a promising tool for the identification of organic toxicants in complex mixtures?

Wastewater effluents, groundwater, surface water, sediments, soils and air particulate matter are often contaminated by a multitude of chemicals. Since often no a priori knowledge of relevant toxicants exists, chemical analysis alone is not an appropriate tool for hazard assessment. Instead, a linkage of effect data and hazardous compounds is required. For that purpose, effect-directed analysis (EDA) was developed, which is based on a combination of biotesting, fractionation procedures and chemical analytical methods. Since a controversial discussion about the prospects of success in relation to the expense exists, the current methodological state of EDA for organic toxicants in complex mixtures and important results are reviewed in this paper with the aim of establishing criteria for the successful use of this promising tool. While EDA is a powerful tool to identify specifically acting individual toxicants close to the source of emission, it is inappropriate for screening purposes and often may fail in remote areas where the concentrations of specific toxicants are too low relative to the nonspecific toxicity of the whole mixture of natural and anthropogenic compounds. The biological tools have to be carefully selected with respect to their ability to detect specific effects and their significance in hazard assessment. Sophisticated chemical tools are required to identify individual toxicants in mixtures of thousands of compounds, which are typical for contaminated environments.

Air Pollutants↗

PubMed2002

[Transfusion medicine in the 2000s, on a reform].

The creation of the Etablissement Français du Sang (EFS) was mentioned in the Law of July 1, 1998, pertaining to sanitary safety. The EFS is the sole operator of blood transfusion. With a unique legal status, supervised by the Ministry in charge of Health, the EFS organizes the activities involved in the transfusion chain over the whole territory, it promotes research activities and take part in international scientific cooperation. Its activities include medical biology as well as cell and gene therapy. As part of the new 2000-2004 territorial transfusion scheme, the EFS network comprises 18 centers (versus 43 in the previous plan), 14 of which are located in the French territory and the other 4 overseas. The network includes 18 technical platforms for the biological qualification of blood products, while 27 are dedicated to their preparation, transformation and storage. The activities of collection and distribution, which comply with the principle of proximity to both donors and patients, are ensured by 220 sites spread over the whole territory. For the future, the EFS wants to focus its efforts on reducing residual infectious risks (using molecular biology tools), preventing immunological risks, drawing up an education program aiming at teaching transfusion medicine differently. Despite the advances achieved in biotechnologies, the development of substitution products to replace blood transfusion will still require a lot of time. The EFS wishes to focus its action following three different axes: transfusion medicine, medical biology and cell engineering. With its 18 centers and its 8,200 persons, the EFS must face the challengers of the 2000s, relying on the advances in biotechnologies.

Blood Banks↗

PubMed1999

Molecular mechanisms of vitamin E transport.

If the function of vitamin E is that of an antioxidant and the various forms of vitamin E have similar antioxidant activities, then why does RRR-alpha-tocopherol have the highest biologic activity? This chapter describes how interactions by investigators from various scientific disciplines using stable isotopes, molecular biology tools, and sophisticated genetic studies of humans with vitamin E deficiency have led to an understanding of this problem. This chapter provides an overview of (a) studies using deuterated tocopherols that demonstrated that the plasma preference for alpha-tocopherol is dependent on metabolic processes in the liver; (b) the isolation, molecular biology, and function of the alpha-tocopherol transfer protein; and (c) studies that demonstrated that patients who were vitamin E deficient as a result of no known cause had defective alpha-tocopherol transfer protein genes. Finally, we focus on the future--what remains to be learned about the regulation of vitamin E in tissues.

Animals↗

PubMed1993

[Cytokine assay: value and limitations].

Cytokines are proteins with multiple functions indispensable to body homeostasis. They are also good indicators of certain diseases which they are sometimes suspected to induce (e.g. septic shock, allograft rejection). Making cytokine assay methods available to scientists and clinicians has been a notable step forward in the understanding of numerous illnesses. However, these quantitative assays create more problems than they solve, and although reliable and easy tests exist we cannot recommend their use in routine clinical practice. In 1992, cytokine assays must be reserved for research studies where their results in patient populations are meaningful and where they can usefully be completed by other detection methods, such as amplification by polymerase chain reaction or hybridization in situ. Nevertheless, the constant improvement of assay kits, the ever increasing number of cytokines that can be quantified by simple laboratory tests and a better study of interactions between cytokines, their soluble receptors and their natural inhibitors will perhaps make it possible, in the near future, to analyse finely the immune response in not very invasive samplings. Moreover, there are hopes that modern molecular biology tools will soon be available in daily clinical practice. For instance, the development of automated methods for amplification by polymerase chain reaction will provide useful information on the activation of the immune system in various clinical situations. Such techniques, combined with measurements of local or circulating cytokine concentrations are undoubtedly promising tools. Finally, cytokine assays are essential to research workers who can study, within well-defined systems, the kinetics of production and the respective role played by these mediators.

Biological Assay↗

PubMed2002

Mechanisms and means of detection of biocontrol activity of Pseudozyma yeasts against plant-pathogenic fungi.

Fungi belonging to Pseudozyma spp. represent a small group of yeasts that have drawn limited interest in the scientific literature. However, new research with one species of Pseudozyma, Pseudozyma flocculosa, has demonstrated the potential of this yeast as a biocontrol agent of plant-pathogenic fungi. Based on recent work, it appears that P. flocculosa, a natural inhabitant of the phyllosphere, possesses unique means of defending its ecological niche by producing unusual extracellular fatty acids that are detrimental to, among other fungi, powdery mildews, an important group of plant pathogens. Results from these studies have shown that the fatty acids naturally insert themselves into powdery mildew fungi and cause disorganization of cellular membranes and cell disintegration. Further work with insertional mutagenesis yielded mutants of P. flocculosa that represent valuable biological tools to better understand the properties of the yeast. For instance, preliminary work with mutants having lost their antagonistic properties has led to the isolation of a new metabolite with antifungal activity. Discoveries pertaining to the ecology and mode of action of P. flocculosa may lead to the study of unique metabolic or biological processes in other Pseudozyma spp. that could well release the untapped potential of these misunderstood yeasts.

Antibiosis↗

PubMed2005

Making better transgenic models: conditional, temporal, and spatial approaches.

Over the last decade transgenic mouse models have become a common experimental tool for unraveling gene function. During this time there has been a growing expectation that transgenes resemble the in vivo state as much as possible. To this end, a preference away from heterologous promoters has emerged, and transgene constructs often utilize the endogenous promoter and gene sequences in BAC, PAC and YAC form without the addition of selectable markers, or at least their subsequent removal. There has been a trend toward controlled integration by homologous recombination, either at a characterized chromosomal localization or in some cases within the allele of interest. Markers such as green fluorescent protein (GFP), beta-galactosidase (LacZ), and alkaline phosphatase (AP) continue to be useful to trace transgenic cells, or transgene expression. The development of technologies such as RNA interference (RNAi), are introducing new ways of using transgenic models. Future developments in RNAi technology may revolutionize tissue specific inactivation of gene function, without the requirement of generating conditionally targeted mice and tissue specific recombinase mice. Transgenic models are biological tools that aid discovery. Overall, the main consideration in the generation of transgenic models is that they are bona fide biological models that best impart the disease model or biological function of the gene that they represent. The main consideration is to make the best model for the biological question at heart and this review aims to simplify that task somewhat. Here we take a historical perspective on the development of transgenic models, with many of the important considerations to be made in design and development along the way.

Animals↗

PubMed2002

Non-myeloablative stem cell transplantation for the treatment of cancer and life-threatening non-malignant disorders; past accomplishments and future goals.

Allogeneic bone marrow or blood stem cell transplantation (BMT) represents an important therapeutic tool for treatment of otherwise incurable malignant and non-malignant diseases. Until recently, autologous and allogeneic bone marrow or mobilized blood stem cells transplantation were used primarily to replace malignant, genetically abnormal or deficient immunohematopoietic compartment and therefore, highly toxic myeloablative regimen were considered mandatory for more effective eradication of all undesirable host-derived hematopoietic elements. Our preclinical and ongoing clinical studies indicated that much more effective eradication of host immunohematopoietic system cells could be achieved by adoptive allogeneic cell therapy with donor lymphocyte infusion following BMT. Thus, eradication of blood cancer cells, especially in patients with CML and less frequently in patients with other hematologic malignancies, could be frequently accomplished despite complete resistance of such tumor cells to maximally tolerated doses of chemoradiotherapy. Our cumulative experience suggested that graft versus leukemia (GVL) effects might be a useful tool for eradication of otherwise resistant tumor cells of host origin. Based on the cumulative clinical experience and experimental data in animal models of human diseases it appears that induction of host versus graft tolerance as step one, may allow durable engraftment of donor immunocompetent lymphocytes, which may be used for induction of effective biologic warfare against host-type immunohematopoietic cells that need to be replaced, malignant, genetically abnormal or self-reactive alike. Based on the aforementioned rationale, we speculated that the therapeutic benefit of BMT may be improved by using a safer conditioning as part of the transplant procedure, with the goal in mind to induce host versus graft tolerance to enable subsequent induction of GVL, possibly graft versus tumor or even graft versus autoimmunity effects, rather than attempt to eliminate host cells with hazardous myeloablative chemoradiotherapy. The latter hypothesis suggested that effective BMT procedure may be accomplished without lethal conditioning of the host, using new well tolerated non-myeloablative regimen, thus possibly minimizing immediate and late side effects related to myeloablative procedures considered until recently mandatory for conditioning of BMT recipients. Recent clinical data that will be presented suggests that effective BMT procedures may be accomplished with well-tolerated non-myeloablative stem cell transplantation (NST) regimen, with no major toxicity. Thus, new NST approaches may offer the feasibility of safer BMT procedure for a large spectrum of clinical indications in children and elderly individuals without lower or upper age limit, while minimizing procedure-related toxicity and mortality. Taken together, our cumulative data suggest that high dose chemotherapy and radiation therapy may be successively replaced by a more effective biologic tool, alloreactive donor lymphocytes, thus setting the stage for innovative therapeutic procedures for safer and more effective treatment of patients in need of BMT.

Autoimmune Diseases↗

PubMed1997

Molecular temporal bone pathology: I. Historical foundation.

The application of molecular biology techniques to temporal bone research is resulting in rapid changes in our understanding of the fundamental mechanisms of auditory, facial nerve, and vestibular function. The use of the polymerase chain reaction, cDNA libraries, and in situ hybridization histochemistry, the determination of genetic defects, and the manipulation of transgenic animals are the molecular biology tools that are available to approach these research problems. Knowledge of the molecular pathology that results in the otologic and neuro-otologic dysfunction many of our patients experience is currently in its infancy. A review of the historical foundation of temporal bone pathology and the evolution of the application of cell and molecular biology methods to archival celloidin-embedded human temporal bone material is presented.

Animals↗

PubMed1999

What can we learn from murine models of asthma?

Even though a complex disease such as asthma does not have a comprehensive animal model, some characteristics can be duplicated in mice and guinea-pigs. The murine model offers advantages with respect to strain control and availability of molecular biology tools. We introduced the use of the BP2 'Biozzi' mice, which have high IgE titres and expresses bronchopulmonary hyperresponsiveness (BHR) after a single antigenic provocation. BHR is accompanied by airway sequestration of lymphocytes and eosinophils, and by a newly described IgE-bearing granulocyte, identified to basophils. The murine model permits studies for cellular and molecular biology and to investigate the mode of action of drugs.

Animals↗