Trace elements in hair of blackfoot disease

Blackfoot disease is a peripheral vascular disease resulting in gangrene of the lower extremities. Though extensive epidemiological study has implicated that high arsenic content in artesian well water of the endemic area, bears some important connection with the disease, the etiology of the disease is still unknown. In this study, attention is paid to multielement determination in order to find out whether the trace elements in hair of Blackfoot disease patients are different from those of the controls. Experimental results indicate that the concentrations of As and Se in hair of patients are significantly higher than those of the controls, but Ca and Zn are significantly lower than those of the controls. The possible connection of these elements with the etiology of the disease is discussed.     

The effect of pulsed microwaves on passive electrical properties and interspike intervals of snail neurons

The effects of pulsed microwaves (2.45 GHz, 10 μs, 100 pps, SAR: 81.5 kW/kg peak, 81.5 W/kg average) on membrane input resistance and action potential (AP) interval statistics were studied in spontaneously active ganglion neurons of land snails (Helix aspersa), at strictly constant temperature (20.8±.07°C worst case). Statistical comparison with sham-irradiated neurons revealed a significant increase in the mean input resistance of neurons exposed to pulsed microwaves (P ? .05 ). Pulsed microwaves had no visible effect on mean AP firing rate; this observation was confirmed by analysis of interspike intervals (ISIs). Using an integrator model for spontaneously active neurons, we found the net input current to be more variable in neurons exposed to pulsed microwaves. The mean input current was not affected. The standard deviation of ISIs and the autocorrelation of the input current were marginally affected, but these changes were not consistent across neurons. Although the observed effects were less obvious than those reported in other studies, they represent evidence of a direct interaction between neurons and pulsed microwaves, in the absence of macroscopic temperature changes. The data do not suggest a single, specific mechanism for such interaction. © 1993 Wiley-Liss, Inc.     

Psychological perspectives of ecosystem health

Behavior-based and person-based perspectives are integrated to summarize approaches for dealing with the human element of ecosystem health. Behavior is selected by its consequences, and therefore interventions are needed to decrease the natural reinforcing consequences (e.g., convenience, efficiency) of environment-destructive behaviors and to increase the reinforcing consequences of environment-protective behaviors. An ABC Model (for Activator-Behavior-Consequence) can be applied effectively to design intervention programs for benefiting the human behavior aspects of ecosystem health. However, intervention agents are needed to implement positive behavior-change techniques, and this requires people to actively care enough to emit other-directed (or altruistic) behaviors for the health of the ecosystem. Person factors which influence one's propensity to actively care include: self-esteem, belongingness, and empowerment, influenced by perceptions of self-efficacy (I can do it), personal control (I am in control), and optimism (I expect the best). Strategies are reviewed for increasing these person states or expectancies. The health of our ecosystem depends upon people changing their behaviors and attitudes regarding the environment. Behavior-based psychology offers the technology for changing behaviors and attitudes in desirable directions; person-based psychology offers the states or expectancies needed in people to increase their willingness to actively care for the environment. By applying the theory and principles from these subdisciplines of applied psychology, the critical human element of our ecosystem can be accounted for and managed effectively.     

Immunocytochemical Quantification of Tyrosine Hydroxylase at a Cellular Level in the Mesencephalon of Control Subjects and Patients with Parkinson's and Alzheimer's Disease

Abstract: Parkinson's disease is characterized by massive degeneration of the melanized dopaminergic neurons in the substantia nigra. The functional capacity of the surviving nigral neurons is affected, as indicated by the subnormal levels of tyrosine hydroxylase (TH) mRNA in these neurons and the presence in the parkinsonian mesencephalon of melanized neurons lacking TH immunoreactivity. This is apparently in contradiction with the known overactivity of dopamine synthesis and release that occurs in the remaining dopaminergic terminals. To test the ability of the surviving neurons to express TH protein, a semiquantitative immunocytochemical method was developed. The relative amounts of TH were estimated with a computer-assisted image analysis system in the dopaminergic neurons of representative mesencephalic sections of control and parkinsonian brains and for comparison in brains from patients with Alzheimer's disease. In control brains, the mean TH content per neuron differed from one subject to another and between the different dopaminergic cell groups of the mesencephalon in the same subject. Within a given dopaminergic region, the level of TH was variable among neurons. In patients with Parkinson's disease, the ratio of TH protein content per neuron in the substantia nigra by reference to that of the central gray substance was reduced. In patients with Alzheimer's disease, the amount of TH was selectively reduced in the remaining dopaminergic neurons of the ventral tegmental area, a region characterized by a loss in dopaminergic neurons. The decrease in cellular TH content might therefore be related to the presence of the neurodegenerative process in the area considered. In patients with Parkinson's disease, the incapacity of the surviving neurons to express normal TH levels may reduce the efficiency of the hyperactivity mechanisms that develop in the remaining striatal dopaminergic terminals.     

Diversity of Xiphinema americanum-group Species and Hierarchical Cluster Analysis of Morphometrics

Of the 39 species composing the Xiphinema americanum group, 14 were described originally from North America and two others have been reported from this region. Many species are very similar morphologically and can be distinguished only by a difficult comparison of various combinations of some morphometric characters. Study of morphometrics of 49 populations, including the type populations of the 39 species attributed to this group, by principal component analysis and hierarchical cluster analysis placed the populations into five subgroups, proposed here as the X. brevicolle subgroup (seven species), the X. americanum subgroup (17 species), the X. taylori subgroup (two species), the X. pachtaicum subgroup (eight species), and the X. lambertii subgroup (five species).     

Review of the genus Hippidion Owen, 1869 (Mammalia: Perissodactyla) from the Pleistocene of South America

This review of Hippidion is based on a multivariate analysis of the foot, and some morphological characteristics of the skull and dentition. We recognize only one genus ( Hippidion ) including all the hippidiform horses, with three different species: H. principale, H. devillei and H. saldiasi. The latter species is stratigraphically and geographically restricted to the period from 13000 to 8000 years BP in the southern part of South America. Hippidion principale and H. devillei have a large geographical distribution (Argentina, Bolivia, Chile, Perú, Uruguay, Brazil) through the Upper Pliocene-Upper Pleistocene. Both species show some morphometric variations across their geographic range; these features may result from the environmental characteristics.     

Golgi apparatus isolation and use in cell-free systems

Summary Recent advances in understanding the molecular mechanisms of membrane traffic to and through the Golgi apparatus have been predicated in large measure on the use of permeabilized animal cells, and on completely cell-free systems. These systems have included those addressing inter-Golgi apparatus membrane traffic, endoplasmic reticulum to Golgi apparatus traffic, and endocytotic events. Development of cell-free systems depends on the use of isolated fractions. Specificity is often achieved by using a compartment-specific assay so that the fractions employed can be very crude. More recently cell-free systems also have evolved which employ highly purified and well-characterized cell fractions. The latter may be utilized in the absence of a compartment-specific assay but may require employment of compartment-specific assays for validation. Central to development of cell-free systems for membrane analysis has been the availability of isolated Golgi apparatus, first from plants and later from animal tissues and cells. A major advantage of cell-free systems is that they are most clearly amenable to the investigation of molecular mechanisms of membrane trafficking.Dedicated to Hilton H. Mollenhauer on the occasion of his retirement     

Cytological and molecular characterization of a chromosome interchange and addition lines in Cadet involving chromosome 5B of wheat and 6Ag of Lophopyrum ponticum

Efforts to transfer wheat curl mite (Eriophyes tulipae Keifer) resistance from Lophopyrum ponticum 10X (Podb.) Love to bread wheat (Triticum aestivum L.) have resulted in the production of a number of cytogenetic stocks, including an addition line of 6Ag, a ditelo addition line, and a wheat-Lophopyrum translocation line. Characterization of these lines with C-banding, in situ hybridization with a Lophopyrum species-specific repetitive DNA probe (pLeUCD2), and Southern blotting with pLeUCD2 and a 5S ribosomal DNA probe (pScT7) confirmed that the distal portion of the short arm of 6Ag was translocated onto the distal portion of 5BS (5BL. 5BS-6AgS). It was also determined that the ditelo addition was an acrocentric chromosome of 6AgS.     

The SKS of the KMSKS signature of class I aminoacyl-tRNA synthetases corresponds to the GKT/S sequence characteristic of the ATP-binding site of many proteins

On the basis of protein modification studies and primary structure comparison, we propose that the SKS sequence within the KMSKS signature of the class 1 aminoacyl-tRNA synthetases corresponds to the GKT(or S) sequence considered as a signature of the nucleotide triphosphate-binding site of many proteins.     

Sequence and structural homology among membrane-associated domains of CFTR and certain transporter proteins

A sequence comparison of the two membrane-associated (MA) domains of the cystic fibrosis transmembrane conductance regulator (CFTR), multidrug resistance transporter (MDR), and -factor pheromone export system (STE6) proteins, each of which are believed to contain a total of 12 transmembrane (TM) segments, reveals significant amino acid homology and length conservation in the loop regions that connect individual TM sequences. Similar structural homology is observed between these proteins, hemolysin B (HLYB) and the major histocompatibility-linked peptide transporter, HAM1, the latter two which contain a single MA domain composed of six TM segments. In addition, there are specific sequences that are conserved within the TM segments of the five different membrane proteins. This observation suggests that the folding topologies of the MA domains of MDR, STE6, and CFTR in the plasma membrane are likely to be very similar. The sequence analysis also reveals that there are three characteristic motifs (a pair of aromatic residues, LTLXXXXXXP and GXXL) that are conserved in MDR, STE6, HLYB, HAM1, but not in CFTR. We propose that although CFTR may be evolutionarily related to these other membrane proteins, it belongs to a separate subclass.