Neuropeptides and thirst: The temporal response of corticotropin-releasing hormone and neurotensin/neuromedin N gene expression in rat limbic forebrain neurons to drinking hypertonic saline.

The authors have demonstrated in rats that the ingestion of hypertonic saline for 5 days provides an increasingly complex dehydrating stimulus to the rats. Initially, the stimulus leads to cellular dehydration, but extracellular dehydration develops as ingestion continues beyond 3 days. The initial cellular dehydration provokes modifications to corticotropin-releasing hormone and neurotensin/neuromedin N messenger RNAs (mRNAs) in some neurons of the limbic forebrain, changes that are either maintained or are modified as extracellular dehydration develops. These changes in mRNA content occur in neurosecretory neurons as well as in neurons in hypothalamic and telencephalic regions associated with behavior and autonomic regulation. The authors propose that alterations in peptide mRNAs are allied to altered neuronal signaling processes that direct the different components of the homeostatic response to dehydration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Malaria in Zimbabwe: comparisons of IFAT levels, parasite and spleen rates among high, medium and lower altitude areas and between dry and rainy seasons

OBJECTIVES: To study the extent of malaria prevalence among children at various elevations above sea level and in children during the dry and rainy seasons in Zimbabwe. DESIGN: Cross sectional. SETTING: Primary and secondary schools. SUBJECTS: The number of children (aged about eight years in Grade Three and 13 years in Form One) examined in November 1992 was 103 in Chitungwiza (above 1,200 m), 94 in Gokwe (900 to 1,200 m) and 96 in Sasame (under 900 m). In April 1993 it was 86 in Chitungwiza, 78 in Gokwe and 81 in Sasame. MAIN OUTCOME MEASURE: Indirect Fluorescent Antibody Test (IFAT) levels, parasite and spleen rates. RESULTS: No splenomegaly was detected in children in schools above 900 m. While no parasitaemia was detected in children in schools above 1200 m, one (0.6%, 95% CI to -0.6 to 1.7) child and 37 (20.9%, 95% CI 14.9 to 26.9) children in schools between 900 and 1,200 m and below 900 m, respectively, had parasitaemia. The IFAT levels were lowest in children in areas above 1,200 m and increased significantly with decreasing altitude (x2 for linear trend 332, p < 0.001). The parasite rate in the rainy season (39.5%, 95% CI 28.9 to 50.2) was significantly (p < 0.001) higher than that in the dry season (5.2%, 95% CI 0.8 to 9.7). No significant differences in the IFAT levels (p = 0.208) and in the spleen rates (p = 0.180) were observed between the dry and rainy seasons. Sixty five percent of all children in schools above 1,200 m visiting rural areas used no protective measures against malaria. All children in schools under 900 m reported that their homes were sprayed, but very few other prophylactic measures (seven children used antimalarial drugs and 15 children used a net) were reported. CONCLUSIONS: Malaria acquisition is uncommon above 900 m and the people in these areas are highly vulnerable to malaria.     

Disseminated intravascular coagulation

The diagnosis of disseminated intravascular coagulation associated with intracranial pathology is discussed. This pathological entity is characterized by a diffuse bleeding diathesis. Laboratory studies suggest a consumption of all clotting and fibrinolytic factors with an elevation of fibrin split products as a sign of the fibrinolytic activity. The treatment consists of the administration of packed platelets and fresh frozen plasma to replace the consumed coagulation factors. Heparinization is recommended early to prevent further consumption of coagulation factors and epsilon-aminocaproic acid is recommended later after acute fibrinolysis is diagnosed. Constant coaguloanalytic monitoring is necessary. Although the etiology with massive injury to brain tissue is possibly secondary to autotransfusion of brain tissue thromboplastin, other causes such as hypotension, anoxia, acidosis and hemolysis must be considered.     

Relation between signal detectability theory and the traditional procedures for measuring sensory thresholds: Estimating d' from results given by the method of constant simuli.

The theory of signal detectability assumes that the central effect of a stimulus varies because of physical and neural noise; consequently, the detection of a signal requires a central statistical decision procedure. Similar assumptions have been made by psychophysicists to explain the results of traditional threshold measurement procedures. The interrelations between signal detectability and threshold measures are discussed in relation to psychophysical statistical decision theory, and it is shown that (a) the false positive rate should be related to the Crozier ratio C = ΔΙ/?ΔΙ, and (b) it should be possible to use responses given in the method of constant stimuli to predict the value of d' that will be assigned to a given stimulus by a signal detectability procedure. Evidence supporting both predictions is reported, and the relation between threshold measures and "personality tests" is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vanadia-molybdena catalysts for the oxidation of 2-picoline

A study has been made of the influence of catalyst composition on the gas phase oxidation of 2-picoline over mixed vanadium and molybdenum oxides supported on kieselguhr. It is shown that the formation of partial oxidation products is associated with the existence of a mixed oxide phase. The selectivity for the formation of pyridine-2-aldehyde reaches a maximum when one in six vanadium(V) ions in the V₂O₅ lattice is replaced by a molybdenum(VI) ion. It is suggested that the origin of the selectivity is the formation of isolated (V⁴⁺-O) species.     

Factors, correlates, and problem areas affecting career decision making of a cross-sectional sample of students.

Examined the self-reported impact of 6 general factors affecting career decision making and specifically tested the validity of the Career Factor Checklist (CFC) developed from a model of the lst author et al (1978). 1,436 high school, undergraduate, and graduate students completed the CFC and reported the degree to which 6 general factors and 22 subfactors affected their career decision making. Results show that the CFC measured the 6 general career factors identified by the model. A significant grade main effect and Sex?×?Grade interactions were found for 4 of the 6 factors assessed. Implications are discussed for individual counseling and for preventive programming around the correlates in career decision making. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The decomposition of wustite under mixed chemical reaction/mass transport limitations

Numerical solutions have been obtained for the mixed chemical reaction/diffusion limited planar decomposition of a wustite slab prior to iron metal nucleation. The results of the analysis are presented in dimensionless parameters and predict the iron concentration profile within the slab during decomposition, the total loss of oxygen from the sample, and the concentration of iron at the gas/wustite interface, as a function of time. The formulation of the problem allows solutions to be obtained for reduction in H₂/H₂O or CO/CO₂ gas mixtures at reaction temperatures between 873 K and 1573 K.