Studies on Hematoxylin Stains

Selected formulae and procedures for securing specific objectives in staining with hematoxylin are discussed in this article. The separate sections are numbered serially for ready reference, and the subject matter of the paper is arranged under the following self-explanatory divisions:     

Errata

Chromosomal proteins extracted from calf thymus by 0.35 M NaCl were insoluble at the low salt concentrations needed initially for ion-exchange chromatography. However, the addition of high-affinity carboxymethyl-dextran rendered the precipitated proteins soluble, permitting them to be fractionated by elution from DEAE-Sephacel. In this way, the separation of HMG-1 from HMG-2 was achieved, as well as a partial fractionation of the low mobility group proteins, under conditions that did not disturb the native conformation of the proteins.     

Risk Assessment Using EUSES; Refinement Options to Estimate Atmospheric Transportation by its Operational Priority Substances Model (OPS)

The Operational Priority Substances (OPS) model is part of the European Union System for the Evaluation of Substances (EUSES) and is used to estimate air concentrations and atmospheric depositions for risk assessment of chemicals. Traditionally, EUSES assesses environmental exposure using a standardized scenario based on explicit assumptions and default parameter settings. Under the new European Union REACH legislation—which stands for Registration, Evaluation, Authorisation, and restriction of Chemicals—industry is responsible for the risk assessment of chemicals. The current work investigates the potential impact and importance of source parameter refinement on the emission distribution and environmental fate of chemicals as modelled by OPS. In total, 60 scenarios with different combinations of (non) default values for emission heat content, emission source height, and emission source radius, were run for a typical particle-bound substance. Increasing heat content and emission source height reduced the modelled air concentrations and depositions and caused maximum air concentrations to occur further away from the emission source. Results show that estimated air concentrations and total depositions used for risk assessment can become more realistic by using more site-specific emission source parameters. This article proposes risk assessment refinement options and provides recommendations on future updates of EUSES.     

Reevaluation of the proteins in rabies virus particles.

Protein content and localization of individual proteins of rabies virus have been studied. Four major proteins (estimated molecular weights, about 65,000, 54,000, 37,000 and 21,000), one minor component (molecular weight, about 200,000), and one intermediate (as regards its molar concentration) component (molecular weight, about 43,000) were revealed in rabies virus particles. In subviral particles accumulating in virus-infected cells, the 200,000-, 54,000-, and 37,000-dalton components were revealed. Some properties of the subviral particles allow them to be considered as viral nucleocapsids and the proteins composing them as analogs of L, N, and NS proteins of other rhabdoviruses. Thus, the protein composition of the rabies virus strain studied does not differ from that of other rhabdoviruses.     

Self-regulation of slow cortical potentials in psychiatric patients: Schizophrenia

Slow cortical potentials (SCPs) are considered to reflect the regulation of attention resources and cortical excitability in cortical neuronal networks. Impaired attentional functioning, as found in patients with schizophrenic disorders, may covary with impaired SCP regulation. This hypothesis was tested using a self-regulation paradigm. Twelve medicated male schizophrenic inpatients and 12 healthy male controls received continuous feedback of their SCPs, during intervals of 8 s each, by means of a visual stimulus (a stylized rocket) moving horizontally across a TV screen. The position of the feedback stimulus was a linear function of the integrated SCP at each point in time during the feedback interval. Subjects were required to increase or reduce negative SCPs (referred to pretrial baseline) depending on the presentation of a discriminative stimulus. The correct response was indicated by the amount of forward movement of the feedback stimulus and by monetary rewards. Schizophrenics participated in 20 sessions (each comprising 110 trials), while controls participated in 5 sessions. Compared with the healthy controls, schizophrenics showed no significant differentiation between negativity increase and negativity suppression during the first sessions. However, in the last 3 sessions, patients achieved differentiation similar to controls, demonstrating the acquisition of SCP control after extensive training.     

Adjusting brain dynamics in schizophrenia by means of perceptual and cognitive training

Background

In a previous report we showed that cognitive training fostering auditory-verbal discrimination and working memory normalized magnetoencephalographic (MEG) M50 gating ratio in schizophrenia patients. The present analysis addressed whether training effects on M50 ratio and task performance are mediated by changes in brain oscillatory activity. Such evidence should improve understanding of the role of oscillatory activity in phenomena such as M50 ratio, the role of dysfunctional oscillatory activity in processing abnormalities in schizophrenia, and mechanisms of action of cognitive training.

Methodology/Principal Findings

Time-locked and non-time-locked oscillatory activity was measured together with M50 ratio in a paired-click design before and after a 4-week training of 36 patients randomly assigned to specific cognitive exercises (CE) or standard (comparison) cognitive training (CP). Patient data were compared to those of 15 healthy controls who participated in two MEG measurements 4 weeks apart without training. Training led to more time-locked gamma-band response and more non-time-locked alpha-band desynchronization, moreso after CE than after CP. Only after CE, increased alpha desynchronization was associated with normalized M50 ratio and with improved verbal memory performance. Thus, both types of cognitive training normalized gamma activity, associated with improved stimulus encoding. More targeted training of auditory-verbal discrimination and memory additionally normalized alpha desynchronization, associated with improved elaborative processing. The latter presumably contributes to improved auditory gating and cognitive function.

Conclusions/Significance

Results suggest that dysfunctional interplay of ocillatory activity that may contribute to auditory processing disruption in schizophrenia can be modified by targeted training.     

Vasopressin does not enhance memory processes: a study in human twins

Behavioral effects of lysin-vasopressin (LVP) were investigated applying two paradigms from human experimental psychology. The first task was designed to simulate amnesic symptoms in normals. The second task addressed the emotional value of the items to be processed. Additionally, EEG recordings were used as indicators of the central nervous system effectiveness of LVP. Blood pressure and heart rate measured peripheral arousal. The co-twin control method was employed to increase experimental power. Contrary to the prediction of the vasopressin memory hypothesis none of the specific memory parameters was improved by LVP treatment. Changes in the electrical activity of the brain, but not in blood pressure and heart rate indicated central nervous system actions of LVP. However, interpretation of LVP effects in terms of memory processing seems not to be justified.     

Prediction of High Incidence of Dengue in the Philippines

Background

Accurate prediction of dengue incidence levels weeks in advance of an outbreak may reduce the morbidity and mortality associated with this neglected disease. Therefore, models were developed to predict high and low dengue incidence in order to provide timely forewarnings in the Philippines.

Methods

Model inputs were chosen based on studies indicating variables that may impact dengue incidence. The method first uses Fuzzy Association Rule Mining techniques to extract association rules from these historical epidemiological, environmental, and socio-economic data, as well as climate data indicating future weather patterns. Selection criteria were used to choose a subset of these rules for a classifier, thereby generating a Prediction Model. The models predicted high or low incidence of dengue in a Philippines province four weeks in advance. The threshold between high and low was determined relative to historical incidence data.

Principal Findings

Model accuracy is described by Positive Predictive Value (PPV), Negative Predictive Value (NPV), Sensitivity, and Specificity computed on test data not previously used to develop the model. Selecting a model using the F_0.5 measure, which gives PPV more importance than Sensitivity, gave these results: PPV = 0.780, NPV = 0.938, Sensitivity = 0.547, Specificity = 0.978. Using the F₃ measure, which gives Sensitivity more importance than PPV, the selected model had PPV = 0.778, NPV = 0.948, Sensitivity = 0.627, Specificity = 0.974. The decision as to which model has greater utility depends on how the predictions will be used in a particular situation.

Conclusions

This method builds prediction models for future dengue incidence in the Philippines and is capable of being modified for use in different situations; for diseases other than dengue; and for regions beyond the Philippines. The Philippines dengue prediction models predicted high or low incidence of dengue four weeks in advance of an outbreak with high accuracy, as measured by PPV, NPV, Sensitivity, and Specificity.