A behavioral probe of the growth of intake potential during the inter-meal interval in the rat.

The rat's willingness to ingest glucose after an initial intraoral intake test was probed by beginning a 2nd intraoral intake test at variable durations (1–220 min). In Exp 1, after an initial meal of 12.5% glucose solution averaging 26.9?±?1.7 ml, the size of the 2nd (probe) meal of the same stimulus increased linearly from 4.0?±?0.9 ml after a 1-min delay to 15.4?±?2.7 ml after a 120-min delay. In Exp 2, intraoral intake of a more concentrated (37.5%) glucose solution rose more slowly as a function of delay from 2.4?±?2.7 ml to 4.9?±?0.6 ml. For each glucose concentration, the linear recovery function and a slope that depends on stimulus concentration are consistent with a role for gastric emptying during the delay in intake recovery. In Exp 3, rats ingested 12.5% or 37.5% glucose to satiety in an initial test and received, after a variable delay, either the same or the other concentration as the probe stimulus. The same volumes were ingested at each delay whether the glucose concentration of the probe stimulus was the same or was switched from that presented in the initial test. This result shows that the taste and caloric properties of the probe stimulus played no role in determining how much of it would be ingested… (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association of age and body weight with periodontal disease in North American dogs

Thirteen hundred and fifty dogs were examined under anesthesia at veterinary hospitals in the USA and Canada. Periodontal health was recorded in detail. Teeth were frequently absent (particularly lower third molar, upper and lower first premolars, and incisor teeth). Calculus was most extensive on the upper fourth premolar and molar teeth. Missing teeth, mobility of remaining teeth, extent of calculus and gingival inflammation, and furcation exposure and attachment loss all were more common in small dogs compared with larger dogs, and in order dogs compared with younger dogs.     

Tower of London performance in relation to Magnetic Resonance Imaging following closed head injury in children.

To investigate the relationship of severity of pediatric closed head injury (CHI), the contribution of frontal lobe lesions, and age at testing (6–10 yr olds vs 11–15 yr olds) to cognitive deficit, 134 head-injured patients were given the Tower of London (TOL) task and underwent magnetic resonance imaging. 89 normal controls were given the TOL for comparison. Severity of CHI and age at testing were strongly related to cognitive performance on the TOL, including the frequency of breaking the rules. Volume of frontal lobe lesion (but not extrafrontal lesion) contributed to the prediction of perfomance on the TOL even after severity of injury was taken into account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prediction of foam growth and its nucleation in free and limited expansion

The influence volume approach (IVA) is often utilized for modeling the mass transfer process dictating bubble growth dynamics in physical foaming. However, the assumed concentration profile in the IVA method is only valid when the changes in dissolved gas concentration are small (less than 5%). In addition, the validity of the IVA method is difficult to justify in chemical foaming applications because of the difficulties involved in defining the dissolved gas concentration profile.In the present work, we define two distinct stages of bubble growth for physical foaming. These two stages are termed as free and limited expansion and are controlled by the bubble nucleation rate. Bubble nucleation is assumed to occur only in the free expansion stage. In this stage, the bubble pressure drops substantially from an initially high pressure in the supersaturated state while the dissolved gas concentration changes very little. The second stage of our two-stage mass transfer model is termed the limited expansion stage and accounts for bubble growth in the late stages of foam evolution, when the pressure changes become small. However, in the limited stage of bubble growth the dissolved gas concentration drops significantly, as the available dissolved gas is depleted. To summarize our two-stage mass transfer model of foam expansion, the pressure difference between the bubble phase and the liquid phase is the primary mechanism for driving mass transfer in the early (free) stages of foam growth and the concentration difference is the driver for bubble growth in the late (limited) stages of growth. The first stage can be regarded as the nucleation stage and it is relatively short; while the second stage can be regarded as the bubble growth stage and is much longer. Most of the bubble volume expansion takes place in the second stage.The concentration gradient at the bubble edge, which is often ignored in other models, is analyzed in detail in this paper. The details of our novel mass transfer model are also presented.     

Effects of halothane anesthesia on the motility of the sphincter of Oddi and transsphincteric flow in Australian brush-tailed possums

We evaluated the effect of halothane anesthesia on the motility of the sphincter of Oddi and simultaneous transsphincteric flow in Australian Brush-tailed possums (Trichosurus vulpecula). Halothane levels in the range of 0.25 to 2% were administered and decreased transsphincteric flow in a dose-dependent manner. Sphincter of Oddi basal pressure was higher than normal, but not in a dose-dependent manner. Additionally, halothane anesthesia influenced the sphincter of Oddi motility by decreasing the motility index (mean amplitude multiplied by frequency of contractions). This decrease was dose dependent. These findings indicate that sphincter of Oddi basal pressure is a major component of sphincter of Oddi motility responsible for regulating transsphincteric flow in this species. For studies of the sphincter of Oddi motility in anesthetized Australian Brush-tailed possums, we recommend anesthetic induction with ketamine (50 mg/kg, i.m.) and the inspired halothane level should not exceed 0.75% during the study period, as the effects we have demonstrated were most evident at levels greater than 0.75%. If higher halothane levels are required to maintain satisfactory anesthesia, an alternative anesthetic agent should be considered.     

Carbachol can potentiate N-methyl-D-aspartate responses in the rat hippocampus by a staurosporine and thapsigargin-insensitive mechanism

Experiments were performed to investigate the mechanism underlying the potentiation of N-methyl-D-aspartate (NMDA) responses by carbachol (CCh) in the CA1 region of rat hippocampal slices. CCh (300 nM) potentiated responses to NMDA, but not to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), in a readily reversible manner. Potentiation occurred in slices treated with 200 nM tetrodotoxin and perfused with Mg(2+)-free medium. It also occurred in slices treated with either staurosporine (1 microM), which is a potent inhibitor of a variety of protein kinases including protein kinase C (PKC), or thapsigargin (10 microM), which depletes intracellular Ca2+ stores by preventing their refilling. However, CCh-induced potentiation was abolished in slices perfused with Ca(2+)-free medium. These data suggest that low concentrations of CCh can acutely potentiate NMDA responses in the hippocampus by a Ca(2+)-sensitive process that is probably independent of both the activation of PKC and the release of Ca2+ from intracellular stores. This mechanism is similar to that underlying the potentiation of NMDA responses by the metabotropic glutamate receptor (mGluR) agonist, aminocyclopentane-1S,3R-dicarboxylic acid (1S,3R-ACPD).