V.A.C. instillation: in vitro model. Part 2.

The behavior of a liquid in foam in the course of the V.A.C. instillation was investigated in an in vitro model by visualization using an aqueous color solution and by a quantitative determination of changing concentration of Ringerlactate solution.     

Melatonin and childbearing: Part 2. Postimplantation period

In this part of the review, we have tried to consider the dependence of the pineal hormone melatonin in human blood serum. It was established that one of the main functions of melatonin is the synchronization of all organs and the regulation of seasonal and diurnal rhythms of their physiological activity. It is confirmed that pregnancy and childbirth directly depend on the rhythm and level of melatonin secretion in the body. It was also found that melatonin maintains the appropriate proliferative level and immune status of the fetus. Disturbances in the melatonin secretion rhythm in children lead to the development of mental (stress and depression) and physiological (preeclampsia, eclampsia, fetal hypoxia, and miscarriages) pathologies. A drastic decrease in the melatonin concentration initiates the childbirth process. Therefore, the creation of conditions for maintaining a sufficient level of melatonin is required to ensure the birth of healthy offspring.     

Determination of ochratoxin A in liquorice products using HPLC-based analytical methods. Part II: harmonised method and method validation study

On the basis of the outcome of an European proficiency test series conducted on behalf of the CAOBISCO (Association of the Chocolate, Biscuit and Confectionery Industries of the EU) expert group on ochratoxin A, a new harmonised method was developed for the analysis of ochratoxin A in liquorice extracts. This method works without the use of halogenated solvents because, as the proficiency test showed, an aqueous extraction solution can be used instead of, for example, chloroform, whose use is restricted in the EU. The main objective of this method validation study was to check the performance of this harmonised method. To carry out the method validation study, a set of three different test samples (one liquorice powder and two liquorice pastes) and a liquorice powder sample with an indicated range of ochratoxin A (a so-called sunshine sample) was distributed to 21 laboratories in ten countries throughout Europe and to one laboratory in the USA. The study was evaluated according to internationally recognised guidelines. In terms of its repeatability and reproducibility for determining ochratoxin A in liquorice extracts with a relative standard deviation for repeatability (RSD_r) of between 6.68 and 19.95 and a relative standard deviation for reproducibility (RSD_R) of between 17.39 and 29.08 the performance of the harmonised method was found to be in the accepted range of the EU directive for the analysis of mycotoxins in several foodstuffs.     

Student perceptions of mistreatment and harassment during medical school. A survey of ten United States schools.

Senior students at 10 medical schools in the United States responded to a questionnaire that asked how often, if ever, they perceived themselves being mistreated or harassed during the course of their medical education. Results show that perceived mistreatment most often took the form of public humiliation (86.7%), although someone else taking credit for one''s work (53.5%), being threatened with unfair grades (34.8%), and threatened with physical harm (26.4%) were also reported. Students also reported high rates of sexual harassment (55%) and pervasive negative comments about entering a career in medicine (91%). Residents and attending physicians were cited most frequently as sources of this mistreatment. With the exception of more reports of sexual harassment from women students, perceived mistreatment did not differ significantly across variables such as age, sex, religion, marital status, or having a physician parent. Scores from the 10 schools also did not vary significantly, although the presence of a larger percentage of women in the class appeared to increase overall reports of mistreatment from both sexes.     

Cryopreservation of articular cartilage. Part 3: the liquidus-tracking method

Although it is relatively straightforward to cryopreserve living isolated chondrocytes, at the present time there is no satisfactory method to preserve surgical grafts between the time of procurement or manufacture and actual use. In earlier papers we have established that the cryoprotectants dimethyl sulphoxide or propylene glycol do penetrate into this tissue very rapidly. Chondrocytes are not unusually susceptible to osmotic stress; in fact they appear to be particularly resistant. It appears that damage is associated with the formation of ice per se, even at cooling rates that are optimal for the cryopreservation of isolated chondrocytes. We then showed that current methods of cartilage cryopreservation involve the nucleation and growth of ice crystals within the chondrons rather than ice being restricted to the surrounding acellular matrix. This finding established the need to avoid the crystallization of ice—in other words, vitrification. Song and his colleagues have published a vitrification method that is based on the use of one of Fahy’s vitrification formulations. We confirmed the effectiveness of this method but found it to be very dependent on ultra rapid warming. However, we were able to develop a ‘liquidus-tracking’ method that completely avoids the crystallization of ice and does not require rapid warming. The ability of cartilage preserved in this way to incorporate sulphate into newly synthesized glycosaminoglycans (GAGs) approached 70% of that of fresh control cartilage. In this method the rates of cooling and warming can be very low, which is essential for any method that is to be used in Tissue Banks to process the bulky grafts that are required by orthopaedic surgeons. Work is continuing to refine this method for Tissue Bank use.     

The evolution of sexual reproduction as a repair mechanism. Part I. A model for self-repair and its biological implications

Summary The theory is presented that the sexual process is a repair mechanism which maintains redundancy within the sub-structure of hierarchical, self-reproducing organisms. In order to keep the problems within mathematically tractable limits (see Part II), a simple model is introduced: a wheel with 6 spokes, 3 of them vital and 3 redundant, symbolizes the individual (cell or organism). Random accidents destroy spokes; the wheels replicate at regular cycles and engage periodically in pairing and repair phases during which missing spokes are copy-reproduced along the intact spokes of the partner wheel.The hierarchical structure of such a system is analysed and an autonomous unit is defined: this is the unit of minimal hierarchical complexity which is capable of perpetuating autonomously all higher and all lower levels of the hierarchy; this is the central unit of selection.Four basic, physical parameters are isolated which determine the essential features of any eucaryotic life cycle: 1. The number of levels of the hierarchy (unicellular, multicellular, colonial, etc.); 2. the relation between the phases of replication (asexual generations) and repair (sexual generations); 3. the duration of potential repair (haplo- diplo-phases); 4. the position of the sexual partners within the hierarchy (selfing, monecy, dioecy, reproductive individuals within colonies, etc.).The evaluation of fitness components is considered in relation to trends of reproductive patterns in evolution.     

The European carbon balance. Part 2: croplands

We estimated the long‐term carbon balance [net biome production (NBP)] of European (EU‐25) croplands and its component fluxes, over the last two decades. Net primary production (NPP) estimates, from different data sources ranged between 490 and 846 gC m^?2 yr^?1, and mostly reflect uncertainties in allocation, and in cropland area when using yield statistics. Inventories of soil C change over arable lands may be the most reliable source of information on NBP, but inventories lack full and harmonized coverage of EU‐25. From a compilation of inventories we infer a mean loss of soil C amounting to 17 g m^?2 yr^?1. In addition, three process‐based models, driven by historical climate and evolving agricultural technology, estimate a small sink of 15 g C m^?2 yr^?1 or a small source of 7.6 g C m^?2 yr^?1. Neither the soil C inventory data, nor the process model results support the previous European‐scale NBP estimate by Janssens and colleagues of a large soil C loss of 90 ± 50 gC m^?2 yr^?1. Discrepancy between measured and modeled NBP is caused by erosion which is not inventoried, and the burning of harvest residues which is not modeled. When correcting the inventory NBP for the erosion flux, and the modeled NBP for agricultural fire losses, the discrepancy is reduced, and cropland NBP ranges between ?8.3 ± 13 and ?13 ± 33 g C m^?2 yr^?1 from the mean of the models and inventories, respectively. The mean nitrous oxide (N₂O) flux estimates ranges between 32 and 37 g C Eq m^?2 yr^?1, which nearly doubles the CO₂ losses. European croplands act as small CH₄ sink of 3.3 g C Eq m^?2 yr^?1. Considering ecosystem CO₂, N₂O and CH₄ fluxes provides for the net greenhouse gas balance a net source of 42–47 g C Eq m^?2 yr^?1. Intensifying agriculture in Eastern Europe to the same level Western Europe amounts is expected to result in a near doubling of the N₂O emissions in Eastern Europe. N₂O emissions will then become the main source of concern for the impact of European agriculture on climate.     

Surfactants in microbiology and biotechnology: Part 2. Application aspects

Surfactants are amphiphilic compounds which can reduce surface and interfacial tensions by accumulating at the interface of immiscible fluids and increase the solubility, mobility, bioavailability and subsequent biodegradation of hydrophobic or insoluble organic compounds. Chemically synthesized surfactants are commonly used in the petroleum, food and pharmaceutical industries as emulsifiers and wetting agents. Biosurfactants produced by some microorganisms are becoming important biotechnology products for industrial and medical applications due to their specific modes of action, low toxicity, relative ease of preparation and widespread applicability. They can be used as emulsifiers, de-emulsifiers, wetting and foaming agents, functional food ingredients and as detergents in petroleum, petrochemicals, environmental management, agrochemicals, foods and beverages, cosmetics and pharmaceuticals, and in the mining and metallurgical industries. Addition of a surfactant of chemical or biological origin accelerates or sometimes inhibits the bioremediation of pollutants. Surfactants also play an important role in enhanced oil recovery by increasing the apparent solubility of petroleum components and effectively reducing the interfacial tensions of oil and water in situ. However, the effects of surfactants on bioremediation cannot be predicted in the absence of empirical evidence because surfactants sometimes stimulate bioremediation and sometimes inhibit it. For medical applications, biosurfactants are useful as antimicrobial agents and immunomodulatory molecules. Beneficial applications of chemical surfactants and biosurfactants in various industries are discussed in this review.     

Respiratory syncytial virus inhibitors. Part 2: Benzimidazol-2-one derivatives

Structure-activity relationships for a series of benzimidazol-2-one-based inhibitors of respiratory syncytial virus are described. These studies focused on structural variation of the benzimidazol-2-one substituent, a vector inaccessible in a series of benzotriazole derivatives on which 2 is based, and revealed a broad tolerance for substituent size and functionality.     

Antagonists of the human A2A receptor. Part 5: Highly bio-available pyrimidine-4-carboxamides

A novel series of antagonists of the human A_2A receptor have been identified and have been shown to display good potency and high degrees of selectivity over other receptor sub-types. Displaying in vivo potency in commonly used disease models and high oral bio-availability, this class of compounds may serve as clinically useful treatments for the relief of the symptoms associated with Parkinson’s disease.     

A simple, PC-dedicated, implanted digital PIM-radiotelemetric system. Part 2: The multichannel system.

The paper, which is a continuation of the previous one, describes a six-channel, PC-dedicated implanted telemetry system, including the schematic drawings, and explanation of all the differences between a single channel and multichannel system approach. The scheme of an additional multichannel analog output, that makes a pure analog recording possible, even without the PC connection, is also presented. Specific methods for both parallel (Centronics) and serial (RS232C) port interfacing are demonstrated and the controlling software principles are discussed. The representative recordings obtained from animal experiments of simultaneous (direct and integrated) multichannel intestinal EMG (MMC) are shown. The device can also be used for the ECG, EEG and uterine smooth muscle electrical activity recording.