Chronic vascular catheterization in the rat. Adaptation to injections and semi-continous blood sampling for hormonal studies]

A method for frequent sampling of blood and injections of fluids in undisturbed rats is described. The right external jugular vein and the left carotid artery are cannulated without completely blood stream interruption in the vessel. Injection or perfusion can be performed during several weeks. Blood was collected for at least 15 post-operative days. The technique appears suitable for pituitary kinetics studies which can be carried out several times in rats bearing indwelling catheters.     

Biochemical markers predicting response to radiation- and radiochemo-therapy in cancer patients

Ongoing studies carried out worldwide using banks of tumor and non-tumor samples give evidence that perspective markers predicting response of individual patients to intended radiation therapy may be found among some apoptotic indexes, spectrum of specialized proteins, and DNA-based microarray molecular profiling analysis as well determination of single nucleotide polymorphisms in genome of the patients. In the last years there is increasing interest in radiogenomics and characterization of gene expression profiles by DNA (micro)array technique that can predict radioresponse of tumor and non-tumor tissues. So far there are only a few reliable molecular markers predicting response of tumor and non-tumor tissues to radiation.     

Non-invasive optical monitoring of cerebral blood oxygenation in the foetus and newborn: preliminary investigation

Near infra-red spectroscopy was applied as a non-invasive and continuous technique for the in vivo monitoring of blood and tissue oxygenation in human neonates. Monitoring of cerebral blood oxygenation in the wavelength range 775–904 nm was carried out on preterm infants after inducing a transient mild hypoxic change; the measurements were performed either by the transmission or reflection (backscattering) mode of monitoring. The results of these investigations were used to assess the application of the technique to foetal monitoring. A series of foetal monitoring studies was performed to investigate the influence of maternal contractions on foetal cerebral blood oxygenation. Although only changes in haemoglobin concentration can be monitored at present, the results suggest that near infra-red monitoring could provide a non-invasive, real-time monitoring method in intensive neonatal and intrapartum care.     

Sensitive method for the determination of vincristine in human serum by high-performance liquid chromatography after on-line column-extraction

A column-switching high-performance liquid chromatographic method was developed for the determination of vincristine in serum. Sample preparation was carried out by means of on-line column-extraction, using a C₁₈ reversed-phase preconcentration column. This technique is simple (minimizing manual sampling errors), rapid (reduction of time and costs) and can be easily automated. Both ultraviolet and electrochemical detection are possible, but the latter shows a cleaner chromatogram and is, by the use of a new electrochemical detector, far more sensitive (detection limit 0.3 μg/l at a signal-to-noise ratio of 3). A matrix study was carried out (using human serum and urine and two kinds of calf's serum). Although it appeared that the system was matrix-dependent, no difference in matrix effects could be found in the serum or plasma of different patients. Controls for human serum analysis should be prepared in human serum. With the method described, pharmacokinetic studies of vincristine in children can be performed.     

"Brain reading": achievements, perspectives and ethical problems

The new trend in brain research designated as brain reading is considered. This research deals with decoding the informational content of the brain processing via its physiological parameters. Such studies are based on rather complicated methods of mathematical analysis. Single records rather than averaged data are used to reveal their content. Three main streams of studies are distinguished, i.e. the object classification, the emotion recognition and brainotyping. Particularly, the studies directed to recognizing the type of thinking via EEG spectra, carried out in the author's laboratory, are reviewed. The possible outcome of the brain reading technique is considered. Finally it is argued that in the future, the broad application of this technique needs to be controlled with some ethical rules.     

Polarographic measurement of oxygen uptake using lipoxygenase in reverse micelles

Lipoxygenase-catalyzed linoleic acid peroxidation was chosen as a model system to study the applicability of oxygraphy to monitor the oxygen uptake in organic solvents containing reverse micelles. Care was taken to control the oxygen back transfer from the atmosphere to the sample micellar solution, resulting in a significant improvement of electrode response. Under these conditions, lipoxygenase activity was linear up to 100 mug of enzyme. Given the quality of the calibration curve and the good correlation between lipoxygenase and ascorbate oxidase, the described technique is proposed as an alternative method for determining lipoxygenase activity in reverse micelles. The reliability of this technique was confirmed by the good agreement between polarography and classic spectrophotometry in kinetic studies. Preliminary experiments carried out on soybean cells solubilized in a Tween 85-isopropylpalmitate system demonstrated that a light-dependent oxygen uptake can be measured. The authors propose that the Clark-type electrode be employed to study both the activity of oxidasic enzymes in reverse micelles and cell viability and physiology in organic solvents.     

Rapid Survey Technique Using Socio-Economic Indicators to Assess the Suitability of Pacific Island Rural Communities for Kappaphycus Seaweed Farming Development

The literature on economic feasibility of farming seaweeds like Kappaphycus alvarezii in tropical locations is mainly based upon Asian case studies, and often does not take into account social factors in seaweed farming success. Pacific island countries are culturally and economically distinct from Asia, and efforts are now being made to establish seaweed industries here. Past experiences have showed that social factors often outweigh technical factors in determining the success of rural development projects. In addition, Pacific island communities are very diverse in their socio-economic make-up. The particular community chosen for location of a development project is therefore critical to success. Project managers need to recognize in advance the best type of community for seaweed farming development. The objective of this study was to identify socio economic factors that can be used as predictors of project success or failure. Using results of social survey techniques carried out in eight communities within the Fiji Group, a rapid survey technique has been developed which can enable decisions about whether a community is suitable for farming seaweed or not. Though developed from Fiji case studies, the technique can be applied in other rural Asia/Pacific situations.     

The feasibility of computational modelling technique to detect the bladder cancer

A numerical technique, finite element analysis (FEA) was used to model the electrical properties, the bio impedance of the bladder tissue in order to predict the bladder cancer. This model results showed that the normal bladder tissue have significantly higher impedance than the malignant tissue that was in opposite with the impedance measurements or the experimental results. Therefore, this difference can be explained using the effects of inflammation, oedema on the urothelium and the property of the bladder as a distensible organ. Furthermore, the different current distributions inside the bladder tissue (in histological layers) in normal and malignant cases and finally different applied pressures over the bladder tissue can cause different impedances for the bladder tissue. Finally, it is believed that further studies have to be carried out to characterise the human bladder tissue using the electrical impedance measurement and modelling techniques.     

Non-covalent molecular imprinting with emphasis on its application in separation and drug development

The molecular imprinting technique can be defined as the formation of specific nano-sized cavities by means of template-directed synthesis. The resulting molecularly imprinted polymers (MIPs), which often have an affinity and a selectivity approaching those of antibody-antigen systems, have thus been coined "artificial antibodies." MIPs are characterized by their high specificity, ease of preparation, and their thermal and chemical stability. They have been widely studied in connection with many potential applications, including their use for separation and isolation purposes, as antibody mimics (biomimetic assays and sensors), as enzyme mimics, in organic synthesis, and in drug delivery. The non-covalent imprinting approach, developed mainly in Lund, has proven to be more versatile than the alternative covalent approach because of its preparation being less complicated and of the broad selection of functional monomers and possible target molecules that are available. The paper presents a review of studies of this versatile technique in the areas of separation and drug development, with emphasis being placed on work carried out in our laboratory.     

Zur Verwendung von 2-Hydroxyethyl-Methacrylat (GMA) als Einbettungsmedium bei histologischen Untersuchungen in der Phytopathologie

The use of 2-hydroxyethyl-methacrylate (GMA) as embedding medium for histological investigations in phytopathology A new plastic embedding technique is described for subsequent thin sectioning of plant tissues. In comparison to the paraffinmethod the GMA polymerization system is less time consuming. The excellent preservation of well-fixed tissue is fully asserted, as the embedding medium is not removed from the sections. In lightmicroscopic studies convincing results were obtained with different staining procedures; specific evidence for polysaccharides, pectine and nucleic acids was carried out with thin sections of 2-8 μm thickness, also by fluorescence microscopy. The GMA-embedding technique seems to be of value for various histological investigations in phytopathology.     

Factors Affecting the Algicidal and Algistatic Properties of Copper

Data from laboratory studies are presented to show that, whereas five different sources of copper appear to be equally effective as toxic agents for algae, the medium in which toxicity tests are carried out has a great influence on the toxicity of copper. A technique of subculture is described for determining whether a concentration of a chemical is algicidal, algistatic, or nontoxic in action against a specific alga, and demonstrations are given of tests with algae illustrating each class of action.     

Daily Peak Flow Measurements in the Assessment of Steroid Therapy for Airway Obstruction

Measurements of peak expiratory flow can be made by outpatients on themselves. This technique, which may be carried out at home, has proved to be valuable in assessing the effect of steroids and other bronchodilator drugs in relieving airway obstruction.     

Intraperitoneal Fluid Infusion in Children with Gastroenteritis

In a study of 91 babies with dehydration as a result of gastroenteritis the intraperitoneal route was found to be safe and effective in those with mild or moderate dehydration, but not in those who were severely dehydrated. The fluids found to be most effective in the intraperitoneal technique were normal saline with 28 mEq of potassium chloride per litre, or for hypertonically dehydrated babies half-strength Darrow''s solution. This technique can be carried out by a nurse working single-handed if the baby is premedicated with promazine.     

Staining of gastrin cells with lead-Haematoxylin.

Fixation of fragments of human antral mucosa with Helly's fluid allows gastrin-containing cells to be identified by an immunofluorescence technique. Lead-Haematoxylin staining carried out on the same sections shows selective reactivity of the immunofluorescent cells. These findings support the identification of gastrin cells with G cells, known from previous studies to react with lead-Haematoxylin.     

A Rapid Silver Staining and Destaining Technique for the Nucleolus Organizer Region

Silver staining of nucleolar organizing regions (NOR) is common, but a standard protocol is lacking. A modification of a rapid silver nitrate staining technique for NORs is presented here. Advantages of the modified technique include reliability, speed, cost and the fact that it can be carried out in the light.     

Studies of X-chromosome inactivation with an improved histochemical technique for ornithine carbamoyltransferase

Studies of X-linked enzymes provide an approach to the study of tumour and normal cellular development. We have assessed the technique for the histochemical demonstration of one such enzyme, ornithine carbamoyltransferase (EC 2.1.3.3). Various stages in the Mizutani technique for ornithine carbamoyltransferase were re-examined, and the resulting improved technique applied to normal mice and to mice of the sparse fur strain (Spf) known to have an abnormal form of ornithine carbamoyltransferase inherited as an X-linked characteristic. Positive enzyme activity was present in all hepatocytes from normal mice, the strongest reaction being present in the periportal area with a gradual reduction of activity towards the centrilobular region. No activity was demonstrable in hepatocytes from hemizygous male Spf mice. In heterozygous female Spf mice, there was a clear-cut separation of ornithine carbamoyl-transferase-positive and -negative cells. These were present in very variable proportions in different liver lobes and different animals. Preliminary studies were also carried out using a high pH reaction mixture to detect the abnormal enzyme. These studies demonstrate conclusively the X-linkage of ornithine carbamoyltransferase in mice, showing the mosaic pattern of distribution predicted by the Lyon hypothesis. They show that the Spf strain of mice can be used for studies of both development and tumorigenesis in the liver, and that histochemical study of an animal strain with an X-linked enzyme abnormality provides a powerful investigative tool.     

No effects of short‐term exposure to mobile phone electromagnetic fields on human cognitive performance: A meta‐analysis

During recent years, a large number of studies on the effects of electromagnetic fields emitted by cellular mobile phones on human cognitive performance have been carried out. However, the results have been ambiguous. We carried out the current meta‐analysis in order to investigate the impact of electromagnetic fields emitted by mobile phones on human cognition. Seventeen studies were included in the meta‐analysis as they fulfill several requirements such as single‐ or double‐blind experimental study design, and documentation of means and standard deviations of dependent variables. The meta‐analysis was carried out as a group comparison between exposed and non‐exposed subjects. No significant effects of electromagnetic fields emitted by Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) mobile phones were found. Cognitive abilities seem to be neither impaired nor facilitated. Results of the meta‐analysis suggest that a substantial short‐term impact of high frequency electromagnetic fields emitted by mobile phones on cognitive performance can essentially be ruled out. Bioelectromagnetics 33:159–165, 2012. © 2011 Wiley Periodicals, Inc.     

IPNs based on chitosan with NVP and NVP/HEMA synthesised through photoinitiator-free photopolymerisation technique for biomedical applications

Biocompatible interpenetration polymeric network (IPN) hydrogels based on chitosan with N-vinylpyrrolidinone (NVP) as well as its copolymer with 2-hydroxymethyl methacrylate (HEMA) were synthesised using the photopolymerisation technique without the inclusion of any photoinitiator or crosslinking agent. These hydrogels were characterised using the Fourier-transform infrared spectroscopy (FTIR) technique. Equilibrium swelling of these hydrogels was performed in Milli-Q water and drug release studies were carried out using theophylline as the model drug. These tests showed that the IPN comprised of chitosan and NVP with a very small amount of N-hydroxymethyl maleimide (HMMI) included exhibited higher swelling abilities and fast drug release rates than the IPN which contained chitosan, NVP and HEMA. Kinetic studies of water diffusion into these hydrogels and drug release revealed that with the exception of the IPN with HEMA incorporated, the other hydrogels did not adhere to the Fickian diffusion model. These hydrogels were tested for their biocompatibility with human epidermal keratinocyte cells (HaCaT). A positive cell growth as evidenced by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) cell proliferation assay indicated that these hydrogels are non-toxic to human keratinocytes and can be potentially used as biomaterials for biomedical applications.     

Cadmium removal from water environment by a fungus Volveriella volvacea

Biosorption technique was used for removal of cadmium under different conditions from water environment using a biosorbent, Volveriella volvaceas, locally growing fruit bodies of mushroom. Effects of different parameters like pH, sorbent concentration, ionic strength on the removal efficiency of cadmium by V. volvacea were carried out in continuation with adsorption kinetics and equilibrium isotherm experiments. From the kinetics studies it was found that nearly 95% of the total cadmium removal was achieved from cadmium spiked distilled water within first 15 minutes. Isotherm data was best fitted to linearised Langmuir equation and the sorption capacity was found to be varying from 9.13 to 9.33 mg/g for different sizes of sorbent. The uptake of cadmium(II) is a function of pH of the solution and increases with the increasing pH. Increasing ionic strength and the presence of soluble complexing agents such as ethylene diamine tetraacetic acid (EDTA) decrease the sorption of cadmium (II). The presence of other diavalent cations like calcium and magnesium impedes the uptake of cadmium (II). The presence of chloride ion has no significant effect on cadmium (II) removal. The spent biosorbent can effectively be regenerated with acid and can then be reused.The present work was carried out by the financial support in terms of fellowship under the cultural exchange programme of the Indo-Bangladesh government. Special thanks to the Director, Bangladesh Institute of Technology, Dhaka, Bangladesh, for providing leave, which enabled the author in carrying out the research work.