Electrochromogenic Detection of Live Bacteria Using Soluble and Insoluble Prussian Blue

Microbial detection is crucial for the control and prevention of infectious diseases, being one of the leading causes of mortality worldwide. Among the techniques developed for bacterial detection, those based on metabolic indicators are progressively gaining interest due to their simplicity, adaptability, and, most importantly, their capacity to differentiate between live and dead bacteria. Prussian blue (PB) may act as a metabolic indicator, being reduced by bacterial metabolism, producing a visible color change from blue to colorless. This molecule can be present in two main forms, namely, the soluble and the insoluble, having different properties and structures. In the current work, the bacterial-sensing capacity of soluble and insoluble PB will be tested and compared both in suspensions as PB-NPs and after deposition on transparent indium tin oxide-poly(ethylene terephthalate) (ITO-PET) electrodes. In the presence of live bacteria, PB-NPs are metabolized and completely reduced to the Prussian white state in less than 10 h for soluble and insoluble forms. However, when electrodeposited on ITO-PET substrates, less than 1 h of incubation with bacteria is required for both forms, although the soluble one presents faster metabolic reduction kinetics. This study paves the way to the use of Prussian blue as a metabolic indicator for the early detection of bacterial infection in fields like microbial diagnostics, surface sterilization, food and beverage contamination, and environmental pollution, among others.

Sonochemical coating of Prussian Blue for the production of smart bacterial-sensing hospital textiles

In healthcare facilities, environmental microbes are responsible for numerous infections leading to patient's health complications and even death. The detection of the pathogens present on contaminated surfaces is crucial, although not always possible with current microbial detection technologies requiring sample collection and transfer to the laboratory. Based on a simple sonochemical coating process, smart hospital fabrics with the capacity to detect live bacteria by a simple change of colour are presented here. Prussian Blue nanoparticles (PB-NPs) are sonochemically coated on polyester-cotton textiles in a single-step requiring 15 min. The presence of PB-NPs confers the textile with an intensive blue colour and with bacterial-sensing capacity. Live bacteria in the textile metabolize PB-NPs and reduce them to colourless Prussian White (PW), enabling in situ detection of bacterial presence in less than 6 h with the bare eye (complete colour change requires 40 h). The smart textile is sensitive to both Gram-positive and Gram-negative bacteria, responsible for most nosocomial infections. The redox reaction is completely reversible and the textile recovers its initial blue colour by re-oxidation with environmental oxygen, enabling its re-use. Due to its simplicity and versatility, the current technology can be employed in different types of materials for control and prevention of microbial infections in hospitals, industries, schools and at home.

Care in patients with epidermal necrolysis in burn units. A nursing perspective

OBJECTIVE

To describe how nursing care is delivered to patients with epidermal necrolysis in burn units/specialized units in Spain and a selection of countries.

METHOD

Descriptive cross-sectional study. Data were collected through a structured questionnaire which was sent to nurse managers in all burn units in Spain and a selection of countries. Descriptive statistics was used to summarize the results.

RESULTS

All BU/SUs in Spain (n=12) and seven BU/SUs from a selection of countries completed the questionnaire. A lack of specific nursing protocols on Epidermal Necrolysis was observed in most burn units in Spain. Skin cleansing techniques such as showering were only reported by participants from Spain. Use of antiseptics was less frequent in other countries. Conservative skin management was the most extended practice reported by all participants. The use of vaginal molds to prevent synechiae and coverage of the ocular surface with amniotic membrane to minimize sequelae were rarely reported. Pain assessment was not always documented in sedated patients and few participants reported the use of specific scales for this purpose. All nurses agreed in the need for consensus nursing care guidelines on the disease.

CONCLUSIONS

Nursing care in patients with epidermal necrolysis varied between burn units in Spain. Differences and similarities were observed when compared with burn units in other countries. Genital and ocular care were outdated in all BU/SUs. Pain assessment documentation was suboptimal. Evidence-based nursing care guidelines were generally demanded by all participants to help reduce mortality and morbidity of this rare and often devastating disease.

Use of Space in Open Field by Zebra Finches

This paper is a descriptive study of the spatial preferences of the zebra finch, Taeniopygia guttata, when exposed to a novel environment. 18 subjects were observed in a cubic open field of 1 × 1 × 1 m during four 30-min. sessions. Two spatial variables were considered, height and center/periphery. Data show that birds did not position themselves randomly in the open field but chose more frequently the central and higher part of the enclosure and that general activity was greater when the animal was in the center rather than on the periphery. There were no sex differences in the height preferred, but females spent significantly more time in the center than did males. The type of activity engaged in by the birds was also important in relation to the place occupied.

Mitochondrial DNA (mtDNA) and schizophrenia

The poorly understood aetiology of schizophrenia is known to involve a major genetic contribution even though the genetic factors remain elusive. Most genetic studies are based on Mendelian rules and focus on the nuclear genome, but current studies indicate that other genetic mechanisms are probably involved. This review focuses on mitochondrial DNA (mtDNA), a maternally inherited, 16.6-Kb molecule crucial for energy production that is implicated in numerous human traits and disorders. The aim of this review is to summarise the studies that have explored mtDNA in schizophrenia patients and those which provide evidence for its implication in this illness. Alterations in mitochondrial morphometry, brain energy metabolism, and enzymatic activity in the mitochondrial respiratory chain suggest a mitochondrial dysfunction in schizophrenia that could be related to the genetic characteristics of mtDNA. Moreover, evidence of maternal inheritance and the presence of schizophrenia symptoms in patients suffering from a mitochondrial disorder related to an mtDNA mutation suggest that mtDNA is involved in schizophrenia. The association of specific variants has been reported at the molecular level; however, additional studies are needed to determine whether the mitochondrial genome is involved in schizophrenia.

Asperger's disorder in adulthood: a case report

Asperger's disorder is a pervasive development disorder. It involves qualitative disorders in social relationship and communication as well as restricted and repetitive interests and activities, with no delay in language acquisition. Although Asperger's disorder is an illness that begins in childhood, its diagnosis may frequently not be done until later stages. The case presented is about a 21 year old man with a diagnosis of schizoaffective disorder who, after several admissions, was sent to the Rehabilitation Hospital Unit for stabilization and diagnostic study given the atypical features of his case. The psychopathological examination showed disorders in social relationships, psychomotricity and communications that had begun in his childhood. All these data, and the results of the biomedical and psychological diagnostic tests oriented us towards the presence of a dual diagnosis of Asperger's disorder and schizoaffective disorder. The presence of common symptoms between the AD and other psychiatric diseases as well as the possible existence of comorbidity may lead to an incorrect or late diagnosis.

Characterization of recombinant invertase expressed in methylotrophic yeasts

We studied, for the first time, characterization of the invertase expressed in the methylotrophic yeasts Hansenula polymorpha and Pichia pastoris in terms of enzyme conformational stability and structural behaviour induced by temperature as a function of pH using enzymic assays, differential scanning calorimetry, fluorescence and CD. The enzyme produced in both hosts was very stable over a broad range of pH values, keeping its enzymic activity and structure above 60 degrees C. Thermal denaturation, as measured by differential scanning calorimetry, was always irreversible. However, the fact that scanning rate had no effect on the calorimetric curves gave us the chance to analyse the data from a thermodynamic point of view. The conformational stabilities were essentially identical under the experimental conditions studied, but stability was always slightly higher in the enzyme expressed in H. polymorpha. This fact indicates that the greater degree of glycosylation of this enzyme form contributed to its increased global stability. Reactivation upon heating at 80 degrees C depends on protein concentration, suggesting that irreversibility could be associated with slow refolding kinetics at high protein concentration.

[Effect of pets on human health: is there a correlation?]

Is there a Relationship? Despite an increasing number of studies devoted to the health benefits of interacting with pets, the empirical evidence of such an effect still remains weak. Many reports comparing health-related variables in pet owners and non-owners do not find significant differences. Some studies find a statistical correlation between pet ownership and better health, but they do not adequately demonstrate that the better health is a result of the pet. There is experimental evidence suggesting that the presence of animals is associated with a lowering of cardiovascular responses to stressors. Accordingly, pets could be used in the therapy of stress-related diseases. Nevertheless, no consistent clinical studies testing this hypothesis have been carried out. Moreover, neither evolutionary nor learning hypothesis for the observed decrease in cardiovascular reactivity have been tested till now. Research on the benefits of pet ownership still are in its preliminary steps. Further studies are needed for the understanding of the underlying psychological mechanisms of human/animal relationship and its therapeutic possibilities.

Geophysical variables and behavior: LXXII. Barometric pressure, lunar cycle, and traffic accidents

This study assessed relationships between traffic accidents and variables of the physical environment. Daily data on traffic accidents over a 4-year period were compared with daily records of barometric pressure and synodic lunar cycle. No significant variations in the number of accidents were found related to barometric height but a significant lunar periodicity was observed for one of the years considered. The number of accidents occurring during the full moon day was lowest; the highest occurred two days before the full moon. Accidents occurred more frequently during crescent moon than during waning moon, but no significant differences were noted when the lunar month was divided into four intervals of new moon, first quarter, full moon, and second quarter.