Simultaneous measurement of opiate-induced histamine release in the periaqueductal gray and opiate antinociception: an in vivo microdialysis study

Histamine release and the subsequent activation of H2 receptors in the periaqueductal gray (PAG) are thought to be important components of morphine antinociception. In vivo microdialysis and antinociceptive testing were simultaneously applied in rats to characterize the effects of morphine on PAG histamine release and determine the relationship between histamine release and antinociception. In the absence of nociceptive (tail pinch) testing, morphine (12.8 mg/kg) induced a delayed, long-lasting release of histamine in the PAG. This effect of morphine was abolished by the opiate antagonist naltrexone (1 mg/kg) but was not mimicked by the mu-preferring agonist fentanyl (0.3 mg/kg), suggesting that activation of an opiate receptor other than, or in addition to, the mu receptor is necessary. In contrast to the findings with fentanyl in untested animals, fentanyl combined with nociceptive testing increased histamine release, even though testing alone had no such effect. Unexpectedly, tail pinch testing inhibited morphine-induced histamine release. These results show that the test procedure alters the action of opiates on histamine release, an effect likely to be the result of the stress of repeated tail pinch testing. Therefore, although histamine release may not be obligatory for all types of opiate antinociception, histamine in the PAG may function as a mediator of stress-induced potentiation of opiate antinociception. Even though the microdialysis technique has been acclaimed for its ability to assess neurochemical and behavioral characteristics simultaneously, the introduction of nociceptive testing clearly can alter the neurochemical systems under study.     

Axisymmetric extrusion through adaptable dies—Part 1: Flexible velocity fields and power terms

An adaptable die is one that not only produces the correct geometrical shape, but also is designed through an adaptable method to impart other desirable properties to the product or process. In this first part of a series of papers, six kinematically admissible velocity fields are developed for use in upper bound models for axisymmetric extrusion through various dies, including extrusion through adaptable dies. Three base velocity fields are presented:

(1) assuming proportional angles in the deformation zone,

(2) assuming proportional areas in the deformation zone, or

(3) assuming proportional distances from the centerline in the deformation zone.

The base velocity is modified by an additional term comprised of two functions. One function allows extra flexibility in the radial direction, and the second function allows extra flexibility in the angular direction. There are two forms of the second function, which meet the required boundary conditions. The flexibility function in the radial direction is represented by a series of Legendre polynomials, which are orthogonal over the deformation region. The power terms derived for these velocity fields for use in upper bound models are also presented.Part 2 of this series compares the results obtained in upper bound models for the six velocity fields for a spherical extrusion die. In Part 3, the use of the best velocity field for extrusion through streamlined dies is developed to determine the adaptable die shape, which minimizes the required extrusion pressure. Additionally, the adaptable die shape is compared with results from Yang and Han for arbitrarily curved and streamlined dies.     

Modeling of slag eye formation over a metal bath due to gas bubbling

When gas is bubbled through a molten metal, overlying slag is pushed to the side forming an open “eye” of exposed metal. Eye sizes were measured in room-temperature modeling over a wide range of conditions including the fluids to simulate slag and metal, gas flow rates, and depths of both fluids. A mechanistic model for eye size was developed from fundamental fluid flow considerations. The model expresses a dimensionless eye area in terms of a density ratio of the fluids and a Froude number. The model is consistent with the present experimental results and those of others in different liquid systems. Finally, previously published correlations for eye size have been critically evaluated.     

Simon-Type Effects: Chronometric Evidence for Keypress Schemata in Typewriting.

In 4 experiments, chronometric evidence for keypress schemata in typing was sought by presenting stimuli to be typed in positions that were displaced from a central fixation point. Reaction times were shorter when stimulus positions corresponded to keyboard locations of the letters to be typed, suggesting that position was an important part of the internal representation of the response. Experiment 1 presented single letters left and right of fixation. Experiment 2 presented single letters above and below fixation. Experiment 3 presented words left and right of fixation and found evidence of parallel activation of keypress schemata. Experiment 4 found no effect of the eccentricity of the keyboard locations and responding fingers, suggesting that response-location codes are categorical, not metric. The results are consistent with D. E. Rumelhart and D. A. Norman's (1982) theory of typewriting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The spatial economics of geothermal district energy in a small, low-density town: a case study of Mammoth Lakes, California

This research focuses on the spatial economics of geothermal district energy (DE) systems that distribute hot fluids through a pipeline network to multiple thermal customers. We argue here that DE is held back by uncertainty about its economic feasibility when implemented in real places. DE works best with high urban densities, but in the US the best geothermal resources are in the less-populated west. Economic geography theory suggests that the optimal size of a DE firm's service area should depend on the trade-off between the economies of scale inherent in a large service area and the greater network development costs and heat loss involved in serving a large area. The HEATMAP© software program developed by Washington State University was used to study the feasibility of numerous scenarios for a proposed DE system in Mammoth Lakes, California. Results indicate that the core area of the town is large enough, dense enough, and in close enough proximity to the resource for profitable DE development. Proposed ski village developments would increase the thermal load density and significantly enhance its ability to remain competitive with other fuels, even in pessimistic sensitivity analyses regarding geothermal heat input costs, public participation, and retro-fitting costs.     

Myeloma stem cells in autografting in multiple myeloma

Autologous transplantation has been used increasingly over the last 10 years for the treatment of multiple myeloma. As is the case in other cancers treated by high-dose therapy and stem cell rescue, the contribution of occult tumor cells in the graft to relapse posttransplant remains to be resolved. In this report, we review the biology and differentiation of plasma cells in the context of their significance as an origin of relapse in multiple myeloma.     

Vitamin D and calcium in the prevention of corticosteroid induced osteoporosis: a 3 year followup

OBJECTIVE: To determine the efficacy and safety of vitamin D 50,000 units/week and calcium 1,000 mg/day in the prevention of corticosteroid induced osteoporosis. METHODS: A minimized double blind, placebo controlled trial in corticosteroid treated subjects in a tertiary care university affiliated hospital. The sample was 62 subjects with polymyalgia rheumatica, temporal arteritis, asthma, vasculitis, or systemic lupus erythematosus. The primary outcome measure was the percentage change in bone mineral density (BMD) of the lumbar spine in the 2 treatment groups from baseline to 36 mo followup. RESULTS: BMD of the lumbar spine in the vitamin D and calcium treated group decreased by a mean (SD) of 2.6% (4.1%) at 12 mo, 3.7% (4.5%) at 24 mo, and 2.2% (5.8%) at 36 mo. In the placebo group there was a decrease of 4.1% (4.1%) at 12 mo, 3.8% (5.6%) at 24 mo, and 1.5% (8.8%) at 36 mo. The observed differences between groups were not statistically significant. The difference at 36 mo was-0.693% (95% CI -5.34, 3.95). CONCLUSION: Vitamin D and calcium may help prevent the early loss of bone seen in the lumbar spine as measured by densitometry of the lumbar spine. Longterm vitamin D and calcium in those undergoing extended therapy with corticosteroids does not appear to be beneficial.