A lysine dehydrogenase-based electrode for biosensing of L-lysine.

An amperometric biosensor for L-lysine based on the recently isolated enzyme lysine dehydrogenase is described. Immobilization of the enzyme onto a platinum electrode is achieved via entrapment within a gelatin support on a cellulose membrane. Anodic detection (at 0.4 V vs. Ag/AgCl) is facilitated by the presence of a redox-mediating ferricyanide ion. The effect of experimental variables such as pH, enzyme loading, applied potential, cofactor and mediator concentrations were evaluated in order to optimize the analytical performance. A detection limit of 7 x 10(-8) M, and linearity up to 7 x 10(-4) M are reported. The fast response permits adaptation for flow injection operation with good precision (RSD = 1.9%) and high sample throughout (40 samples per hour). The high specificity offered by this new enzyme is indicated by the lack of interference by other L-amino acids, alcohols or carbohydrates.     

Graphic monitoring of labour.

The parturograph is a composite record designed for the monitoring of fetal and maternal well-being and the progress of labour. It permits the early recognition of abnormalities and pinpoints the patients who would benefit most from intervention. Observations are made from the time of admission of the mother to the caseroom and recorded graphically. Factors assessed include fetal heart rate, maternal vital signs and urine, cervical dilatation, descent of the presenting fetal part, and frequency, duration and intensity of uterine contractions.     

Copper in the Thames Estuary in relation to the special protection areas

Copper poses a risk to the integrity of the Thames Estuary and Marshes special protection area (SPA) as bioaccumulation within the food chain takes place. This article describes some of the investigations carried out for the Habitats Directive Review of Consents including a review of the methods used to analyse copper samples; analysis of the long-term data sets gathered by the Environment Agency; and modelling work. Mean dissolved copper levels for 2002–2006 are below the 5 μg/l Environmental Quality Standard. Catchment modelling was used to establish total copper budgets both for sources discharging directly to the Tideway and for sources throughout the Thames catchment including sewage treatment works (STWs), industries, non-urban, and urban runoff. The total copper load to the Tideway was estimated to be 36 tonnes/year with 52% of this attributed to STWs. Modelling was used to explore the mixing, transport and fate of copper throughout the estuary taking account of partitioning and the interaction with sediments. The modelling showed how the fourth Water Industry Asset Management Programme (AMP4) improvements to the main London STWs would affect copper concentrations throughout the estuary.     

Effect of sojourn at 4,300 m altitude on electroencephalogram and visual evoked response.

The purpose of the present study was to determine the effect of sojourn at high altitude on cerebral electrical activity. Electroencephalographic (EEG) and visual evoked responses (VER) were recorded from seven healthy males under the following conditions: 1) during the first 2-3 h at 4,300 m altitude when Pao2 was maintained at 90 mmHg (control condition), 2) during the first 2-3 h of hypoxia (Pao2 = 40 mmHg), and 3) at 24- to 48-h intervals during the first 9-12 days of hypoxia. Electrode placement was according to the 10-20 International Electrode System. The VER was recorded from an electrode at the inion referred to the left ear. We found no significant changes from control cerebral electrical activity during the first 2-3 h of hypoxia. One subject's VER amplitude was greater than control on the 2nd and 3rd days of hypoxia and a similar change from control was consistently evident in a second subject beginning the 5th day of hypoxia. These changes suggest cortical depression. After the 5th day changes occurred in the remaining subjects which would be consistent with cortical excitation. In three subjects, EEG frequency was increased, amplitude decreased, and/or spiking became evident. In four subjects VER amplitude was reduced. Our findings provide support for the hypothesis that certain behavioral and physiological changes induced by sojourn at altitude could be caused by alterations in central nervous system function.     

The Increased Basophilia of Tissue Proteins After Oxidation with Periodic Acid

Oxidation by periodic acid (a 1% aqueous solution for 1 hour at 37°C.) greatly enhances the basophilic staining normally present in the keratinized portions of epidermis and hair. It also induces strong basophilia in purified fibrin and in the cytoplasm of smooth and striated muscle fibers, endothelium and the cells of the pancreatic islets and acini Proof is offered that this observed basophilia differs from that of either acid mucopolysaccharides or nucleoproteins. The conclusion is reached that, besides revealing polysaccharides occurring in tissue sections, periodic acid also brings about the formation of strongly acid, basophilic groups. These acid groups have not been identified, but since they may be formed most readily in regions of high sulfur content, it is suggested that sulfide and sulfhydryl groups may be oxidized to the corresponding sulfonic acids which could account for the observed characteristics of the basophilic substances.     

The Current Status of the World’s Primates: Mapping Threats to Understand Priorities for Primate Conservation

International Journal of Primatology - Over the past decades, primate populations have been declining. Four years ago, >60% of species were listed as threatened. As the rate of loss...