Strain on the san andreas fault near palmdale, california: rapid, aseismic change

Frequently repeated strain measurements near Palmdale, California, during the period from 1971 through 1980 indicate that, in addition to a uniform accumulation of right-lateral shear strain (engineering shear, 0.35 microradian per year) across the San Andreas fault, a 1-microstrain contraction perpendicular to the fault that accumulated gradually during the interval 1974 through 1978 was aseismically released between February and November 1979. Subsequently (November 1979 to March 1980), about half of the contraction was recovered. This sequence of strain changes can be explained in terms of south-southwestward migration of a slip event consisting of the south-southwestward movement of the upper crust on a horizontal detachment surface at a depth of 10 to 30 kilometers. The large strain change in 1979 corresponds to the passage of the slip event beneath the San Andreas fault.     

Targeting of diacylglycerol degradation to M1 muscarinic receptors by beta-arrestins

Seven-transmembrane receptor (7TMR) signaling is transduced by second messengers such as diacylglycerol (DAG) generated in response to the heterotrimeric guanine nucleotide-binding protein Gq and is terminated by receptor desensitization and degradation of the second messengers. We show that beta-arrestins coordinate both processes for the Gq-coupled M1 muscarinic receptor. beta-Arrestins physically interact with diacylglycerol kinases (DGKs), enzymes that degrade DAG. Moreover, beta-arrestins are essential for conversion of DAG to phosphatidic acid after agonist stimulation, and this activity requires recruitment of the beta-arrestin-DGK complex to activated 7TMRs. The dual function of beta-arrestins, limiting production of diacylglycerol (by receptor desensitization) while enhancing its rate of degradation, is analogous to their ability to recruit adenosine 3',5'-monophosphate phosphodiesterases to Gs-coupled beta2-adrenergic receptors. Thus, beta-arrestins can serve similar regulatory functions for disparate classes of 7TMRs through structurally dissimilar enzymes that degrade chemically distinct second messengers.     

A modular PIP2 binding site as a determinant of capsaicin receptor sensitivity

The capsaicin receptor (TRPV1), a heat-activated ion channel of the pain pathway, is sensitized by phosphatidylinositol-4,5-bisphosphate (PIP2) hydrolysis after phospholipase C activation. We identify a site within the C-terminal domain of TRPV1 that is required for PIP2-mediated inhibition of channel gating. Mutations that weaken PIP2-TRPV1 interaction reduce thresholds for chemical or thermal stimuli, whereas TRPV1 channels in which this region is replaced with a lipid-binding domain from PIP2-activated potassium channels remain inhibited by PIP2. The PIP2-interaction domain therefore serves as a critical determinant of thermal threshold and dynamic sensitivity range, tuning TRPV1, and thus the sensory neuron, to appropriately detect heat under normal or pathophysiological conditions.     

Estrous cycle in the rat: effects on self-stimulation behavior

The performance of female rats, in pressing a bar for electrical stimulation of the hypothalamus, changes during the estrous cycle. Highest barpressing rates accompany the appearance of vaginal cornification. This increase is not an artifact of increased spontaneous activity at estrus, although the factors underlying these changes in activity may also mediate the changes in self-stimulation behavior.     

Field evaluation of a commercial M-protein vaccine against Streptococcus equi infection in foals

A double-blind randomized clinical trial was undertaken to determine the value of parenterally administered Streptococcus equi M-protein vaccine in foals during an epizootic of strangles. Weaned mixed-breed foals (n = 664) housed on 2 adjacent feed-lots (A and B) arrived over a 5-day period, 2 weeks before primary vaccination. Foals in lot B (n = 114) were randomly administered vaccine (n = 59) or saline solution (placebo; n = 55) on 3 occasions at biweekly intervals. Foals in lot A (n = 450) were given 1 dose of vaccine (n = 225) or placebo. The following clinical observations were scored blindly by a single observer for all foals in lot B and for 120 (randomly sampled) foals in lot A on a single day, 2 (Lot B) and 6 (lot A) weeks after final vaccination: cervical lymphadenopathy, type of bilateral nasal discharge, and palpable swelling at injection site(s). Bacteriologic culture of nasal swab specimens or lymph node aspirates from selected foals with clinical disease yielded S equi. Cervical lymphadenopathy was observed in 17 of 59 (29%) vaccinates and 39 of 55 (71%) nonvaccinated controls in lot B and in 32 of 60 (53%) vaccinates and 29 of 60 (48%) controls in lot A. Contingency chi 2 analysis confirmed significantly lower cervical lymphadenopathy rate (chi 2 = 18.5; P less than 0.001) and prevalence of mucopurulent nasal discharge (chi 2 = 11.4; P less than 0.01) for vaccinates in lot B only. Swelling(s) at the vaccine injection site were palpated in 44% of lot B and 29% of lot A vaccinates vs less than 2% of placebo controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical findings in dogs and cats with lead poisoning

Over an 11-year period, 68 cases of lead poisoning were diagnosed in dogs and three in cats, accounting for 58.6% and 21.4% of the accidental poisonings in dogs and cats, respectively, presented at the Small Animal Clinic, University of Queensland. Of the dogs, 94% showed alimentary tract involvement and 67.6% central nervous system signs. Blood lead concentrations above 0.3 ppm were considered to indicate toxicity when associated with alimentary tract or central nervous system abnormalities. The percutaneous absorption of lead in dogs is proposed as a factor for intoxication.