Automatic control of isolated organ perfusion.

If provided with adequate physiological conditions explanted hearts may continue to operate in the regular beating mode. This property offers the opportunity to substitute extensive animal experiments by investigations on the isolated organs. At the same time it enables the development of an alternative method for the transport of donor hearts for transplantation. Experimental setups for both applications are described in this paper. The focus is laid on the optimisation of handling and effectiveness of these setups by means of automatic control. The method for investigating the controlled system ("plant") for blood gas exchange, and especially the determination of the transfer function for the partial pressure of oxygen are described. The plant was triggered with stepwise changes on the gas side at several operating points. A first order lag element with time delay was chosen as approximation of every transfer function. The parameter 'time delay', 'gain of the plant' and 'time constant' were analysed as to the dependency on blood flow rate, gas flow rate and partial pressure of oxygen at the blood outlet of the oxygenator. As a result an equation was found to calculate the time delay from gas flow rate and blood flow rate. Correlation of gain and time constant with parameters of the plant were obtained, too. The data is used for the design of a controller, adapting to the different operating points of the plant.     

Arenicola marina extracellular hemoglobin: a new promising blood substitute

The need to develop a blood substitute is now urgent because of the increasing concern over Europe's BSE outbreak and the worldwide HIV/AIDS epidemic, which have cut blood supplies. Extracellular soluble hemoglobin has long been studied for its possible use as a safe and effective alternative to blood transfusion, but this has met with little success. Clinical trials have revealed undesirable side effects-oxidative damage and vasoconstriction-that hamper the application of cell-free hemoglobin as a blood substitute. We have addressed these problems and have found a new promising extracellular blood substitute: the natural giant extracellular polymeric hemoglobin of the polychaete annelid Arenicola marina. Here we show that it is less likely to cause immunogenic response; its functional and structural properties should prevent the side effects often associated with the administration of extracellular hemoglobin. Moreover, its intrinsic properties are of interest for other therapeutic applications often associated with hemorrhagic shock (ischemia reperfusion, treatment of septic shock and for organ preservation prior to transplantation). Moreover, using natural hemoglobin is particularly useful since recombinant DNA techniques could be used to express the protein in large quantities.     

Recombinant haemoglobin in the development of red-blood-cell substitutes.

Increasing concern over viral contamination of blood is spurring the development of a blood substitute which can effectively replace the oxygen-carrying capabilities of transfused erythrocytes. Solutions of chemically modified haemoglobin represent one option being evaluated for this role. More recently, recombinant-DNA techniques have enabled production of human haemoglobin in host expression systems, and progress is being made towards the creation of a genetically engineered molecule incorporating the properties required of a blood substitute.     

Blood physiological resources and their role in physiological adaptation of the body to blood loss (based on the experimental data and calculations)

In white rats, loss of about 66 +/- 3% of the blood volume results in an abrupt drop of the BP and arrest of the lung respiration. Introduction of a plasma substitute in the volume equal to the lost blood resulted in an increase of the BP and restoration of rhythmical respiration in 9 out of 14 experimental rats. Haematocrit after the blood loss and subsequent administration of the substitute was about 15%. Previously obtained data show that the Ht of about 15% decreases the oxygen transport to tissues. However, an increase in the lung ventilation, a shift of the haemoglobin dissociation curve to the right, an increase of oxygen extraction from the blood, and an increase in the minute blood volume by 50-100%, allow a sufficient oxygen transport to the organism tissues to be ensured at the Ht of about 15%. Thus, the reserve of the blood respiration function of the blood remaining after a life-threatening blood loss plays an important physiological role in replenishing the volume of the lost blood with the plasma substitute and in survival of the organism.     

Human blood-derived fibrin releasates: Composition and use for the culture of cell lines and human primary cells

We have evaluated the capacity of two human blood fractions to substitute for FBS as growth medium supplement for human and animal cell cultures. Non-anticoagulated blood from volunteer donors (N = 13) was centrifuged to isolate a supernatant serum (SS) and a platelet-rich fibrin (PRF) clot which was squeezed to extract the releasate (PRFR). Both materials were characterized for the content in PDGF-AB, TGF-β1, VEGF, bFGF, EGF, IGF, total protein, albumin, IgG, IgM IgA, fibrinogen, cholesterol, triglycerides, various chemistry analytes and hemoglobin. Cell growth promoting activity of pooled SS and PRFR at 1, 5, and 10% in growth medium was evaluated over 7 days using human (HEK293, MG-63) and animal (SIRC, 3T3) cell lines and two human primary cultures (gingival fibroblasts and periodontal ligaments). Viable cell count was compared to that in cultures in FBS free-medium and 10% FBS supplement. SS and PRFR at 1-10% stimulated cell growth significantly more than FBS-free medium and in a way similar to 10% FBS in all cultures apart from 3T3. These two human blood-derived fibrin releasates are equally efficient to substitute for FBS as supplement for cell cultures and could be useful for specialized applications in regenerative medicine, dentistry and oral implantology, or cell therapy.     

Fluorocarbons as artificial blood substitutes: an electron microscopy study

In spite of the great interest in developing a perfluorocarbon (PFC) blood substitute with a wide range of applications, the in vivo and in vitro knowledge of the interactions between PFCs and cells, from the ultrastructural point of view is limited up to now. In this framework, our observation confirmed the PFC particle uptake by rat hepatocytes in vivo as well as in vitro. The absence of endocytosis by rat and guinea pig myocytes in vivo, to be confirmed by in vitro experiments, could favour a safe use of PFCs as components of cardioplegic solutions.     

Experimental assessment of the effectiveness of modified polyhemoglobin in the model of extreme hemodilution

The efficacy of the modified polyhemoglobin suggested as an artificial oxygen transporting substitute was estimated in the model of extreme hemodilution in dogs. It was shown that O2 consumption in dogs had been supported on the normal level during 4 hours after total exchange transfusion with the polyhemoglobin solution. Index of hemodynamics testifies that preparation has hemodynamics action. The conclusion was made that this modified polyhemoglobin has been effective O2 carrying blood substitute.     

Value of the K+ salt of carageenan as an agar substitute in routine bacteriological media

The K+ salt of carageenan has no distinct advantages as a gelling agent, but it compared favorably with agar in most of the media tested. The difficulty involved in the preparation of blood plates and the results obtained with this medium prohibit its complete acceptance as a substitute for agar in routine solid media. However, it could be a suitable substitute for agar in all other routine bacteriological media.     

Value of the K+ salt of carageenan as an agar substitute in routine bacteriological media.

The K+ salt of carageenan has no distinct advantages as a gelling agent, but it compared favorably with agar in most of the media tested. The difficulty involved in the preparation of blood plates and the results obtained with this medium prohibit its complete acceptance as a substitute for agar in routine solid media. However, it could be a suitable substitute for agar in all other routine bacteriological media.     

Towards the Development of Hemerythrin-Based Blood Substitutes

Hemerythrin is proposed as an alternative to hemoglobin-based blood substitutes. In contrast to hemoglobin, hemerythrin exhibits negligible reactivity towards oxidative and nitrosative stress agents (peroxide, nitric oxide, nitrite). Protocols for attachment of polyethylene glycol and glutaraldehyde cross-linking of Hr are described. These derivatizations appear to have favorable effects on O₂ affinity and autoxidation rates for use in blood substitutes. Based on lessons learned from hemoglobin-based blood substitutes, these derivatizations should also help limit extravasation and antigenicity of a hemerythrin-based blood substitute.     

Optimization of the processing of porcine platelet-rich plasma and its application on human mesenchymal stem cell cultivation

Because of ethical and scientific controversy, the utilization of fetal bovine serum (FBS) for cell culture medium must be minimized. This study develops porcine platelet-rich plasma (P-PRP) as a FBS substitute for human mesenchymal stem cell (hMSC) cultivation. Concentrating porcine blood by serial centrifugation to obtain P-PRP leads to activation by different agonist combinations to stimulate the secretion of growth factors. The concentration of growth factor in P-PRP is significantly increased by activation (p < 0.05). The concentration of PDGF, KGF and TGF-β in activated P-PRP is significantly higher than that in FBS. Design-expert was used to decide whether Co−T+Ca−, Co+T−Ca−, and Co+T+Ca− are optimal agonist formulations. MSC cultivation shows that the attachment rate, proliferation rate and viability of P-PRP supplemented media are significantly higher than those for FBS-supplemented and commercial media (p < 0.05). The results demonstrate that P-PRP is an optimal FBS substitute that supports in vitro h-MSCs expansion for subsequent biomedical applications.     

Examination of the differential hematocrit and the plasma viscosity under the influence of ionizing radiation]

Systematic investigations into the impact of haemorheological parameters through ionizing rays are not available in literature. The main factors influencing the flow capacity of the blood were determined in vitro by using a set of special methods. Even by using high dosages of irradiation (600 R) only those changes in the flow capacity of the blood could be identified which lay in or near the dispersion area of the methods. These investigations carried out in vitro only take into account the immediate effect of the blood and not rheological changes caused by the intact organism after irradiation.     

Microbial synthesis of the sweet-tasting plant protein thaumatin

Thaumatin, the intensely sweet-tasting protein from the African plant, Thaumatococcus daniellii, is a potential low-caloric substitute for sugar and an attractive compound for studying the structural aspects of sweetness perception. Since thaumatin has other properties, such as flavour enhancement, it could also be used in products other than low-calorie foods. Recombinant DNA techniques could be used to synthesize this protein in quantities sufficient for such applications.     

Growth-Regulating Substances and the Growth of Tiller Buds in Barley; Effects of IAA and GA3

Application of cytokinin to barley seedlings grown without mineralnutrients leads to rapid growth of coleoptile and first leaftiller buds. IAA and GA₃ cannot substitute for cytokinin inthis effect and applications of TIBA and CCC are also ineffectiveon bud growth. However, when bud growth was promoted, eitherby application of cytokinins or by supplying plants with mineralnutrients, IAA and GA₃ applications caused enhanced tiller growthindicating that these compounds can stimulate growth of activelygrowing buds. The results are compatible with an interpretationwhich stresses the importance of cytokinin availability in determiningtiller bud growth.     

Towards biosensing of arteriosclerotic nanoplaque formation using femtosecond spectroscopy

The ultrafast dynamics of proteoheparan sulfate (HS-PG) in Krebs blood substitute solution was measured using femtosecond transient absorption spectroscopy after UV excitation. Interacting with blood lipoproteins and Ca(2+) ions, the proteoglycan HS-PG is the key component of the so-called nanoplaque, the earliest stage in atherogenesis. Since tryptophan (Trp) residues are the main optically active parts of HS-PG, analogous measurements were performed on bare Trp in Krebs solution. The comparison reveals distinct differences to main characteristics of the HS-PG broadband absorption spectra. Analyzing the Trp spectra, we show that the results from transient absorption spectroscopy resemble the time constants of the chromophore ultrafast solvation dynamics that have been found by another group using fluorescence up-conversion techniques. Yet, the broadband transient absorption provides more details about the molecular dynamics, including stimulated emission, excited state absorption and resonant energy transfer. Furthermore, the absorption long time dynamics upon adding Ca(2+) to the HS-PG probe were investigated by transient absorption spectroscopy and by surface force and ellipsometry investigations. Notably, a Ca(2+)-induced conformational change responsible for arteriosclerotic nanoplaque formation was detected. Slight differences, which are only visible as broad spectral features in the sub-picosecond time scale, provide a first insight into the molecular formation of nanoplaques in blood vessels, which may yield a better understanding of the genesis of arteriosclerosis.     

Effects of a Fat Substitute,Sucrose Polyester,on Food Intake,Body Composition,and Serum Factors in Lean and Obese Zucker Rats

Sucrose polyester, a fat substitute, has shown promise in reducing blood cholesterol and body weight of obese individuals. Effects of this compound in the Zucker rat, a genetic model of obesity, are unknown. Thus, we examined food intake, body weight, body composition, and several metabolic parameters in sera of lean and obese female Zucker rats. Eight-week-old lean and obese animals were given a choice between a control diet (15% corn oil) and fat substitute diet (5% corn oil and 10% sucrose polyester) for 2 days. Next, one-half of the lean and obese groups received control diet; the remaining lean and obese rats received fat substitute diet for 18 days. Cumulative food intake was depressed in fat substitute groups relative to control-fed animals; however, this effect was more predominant in obese animals. Obese rats consuming fat substitute diet (O-FS) gained less weight as compared to obese control-fed animals (O-C). Lean rats given fat substitute (L-FS) did not have significantly different body weights as compared to the L-C group. Fat substitute groups, combined, had lower body fat and higher body water as compared to controls. The O-FS group had lower serum glucose and insulin and higher fatty acid levels compared to the O-C group. There were no differences in serum cholesterol, HDL, or triglyceride levels due to fat substitute diet. These data suggest that the obese Zucker rat is unable to defend its body weight when dietary fat is replaced with sucrose polyester.     

Human peripheral blood mononuclear cells: A review of recent proteomic applications

Human peripheral blood mononuclear cells (PBMCs) represent a sentinel blood sample which reacts to different pathophysiological stimuli in the form of immunological responses/immunophenotypic changes. The study of molecular content of PBMCs can provide better understanding of immune processes giving the possibility of monitoring the health conditions of the host organism. Proteomic analysis of PBMCs can achieve mentioned goal as important immune-related biomarkers are easily accessible for analysis. PBMCs have been gaining attention in different research areas including preclinical or clinical investigations. In this review, recent applications of proteomic analysis of PBMCs are described and discussed. Approaches are divided based on different proteomic workflows such as in-gel, in-solution and on-filter modes. The effect of various diseases such as autoimmune, cancer, neurodegenerative, viral, metabolic, and various immune stimulations such as radiation, vaccine, corticosteroids over PBMCs proteome, are described with emphasis on promising protein biomarker candidates.     

Determination of cannabinoids by gas chromatography-mass spectrometry and large-volume programmed-temperature vaporiser injection using 25 microl of biological fluid

This paper presents a GC-MS confirmation method, based on large-volume programmed-temperature vaporisation (PTV) injection, for the determination of cannabinoids in plasma samples (or whole blood) with deuterium-labelled internal standards using only 25 microl of biological fluid. The analytes, Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-Delta 9-tetrahydrocannabinol (THC-COOH), were enriched by means of solid-phase extraction cartridges containing octadecyl-bonded silica and were, subsequently, methylated. A 20 microl aliquot of an extract in hexane was injected into a PTV in solvent split mode. Method development and the results of the analyses of standard reference material and real samples are presented and discussed. This micro-method is precise and sensitive enough to assess relevant cannabinoid levels in human blood for forensic investigations as well as for clinical applications.     

椭圆偏振术在生物医学研究中的应用

椭圆偏振术是一种新兴的用于研究生物分子固相表面吸附以及吸附分子间相互作用的表面分析技术。其最大优点在于测量过程不破坏被测体系;而且灵敏度高,可反映接近原子尺寸的变化;又能原位、实时跟踪检测表面膜的变化情况。就椭偏术在生物医学研究的若干重要应用进行综述。     

偶联剂在生物涂层中的应用

综述了生物材料的研究及问题,论述了偶联剂的种类及其作用机理,在此基础上介绍了偶联剂的研究现状与应用概况。重点论述了偶联剂在生物涂层中的应用及其前景。