A kinematic comparison of the locomotor pattern of horses sedated with detomidine alone and in combination with low doses of butorphanol

2019 ◽  
Vol 51 (6) ◽  
pp. 825-830 ◽  
Author(s):  
M. A. Frigerio ◽  
D. Gómez Cisneros ◽  
I. Santiago Llorente ◽  
G. Manso‐Díaz ◽  
J. López‐Sanromán
Keyword(s):  
Low Doses ◽  
Locomotor Pattern

Effects of Intrathecal Glutamatergic Drugs on Locomotion. II. NMDA and AP-5 in Intact and Late Spinal Cats

2003 ◽  
Vol 90 (2) ◽  
pp. 1027-1045 ◽  
Author(s):  
Nathalie Giroux ◽  
Connie Chau ◽  
Hugues Barbeau ◽  
Tomás A. Reader ◽  
Serge Rossignol
Keyword(s):  
Excitatory Amino Acids ◽  
Early Stage ◽  
Pattern Generator ◽  
Major Effect ◽  
Low Doses ◽  
Receptor Stimulation ◽  
Locomotor Pattern ◽  
Weight Support ◽  
Spontaneous Expression ◽  
Nmda Receptor Blocker

In a previous article, we have shown that, in cats, intrathecal injections of N-methyl-d-aspartate (NMDA) in the first few days after spinalization at T13 do not induce locomotion as in many other spinal preparations. This is in contrast to alpha-2 noradrenergic receptor stimulation, which can trigger locomotion at this early stage. However, it is known that spinal cats do recover spontaneous locomotion in the absence of descending noradrenergic pathways and that the spinal pattern generator must then depend on other neurotransmitters still present in the cord such as excitatory amino acids. In the present paper, therefore we look at the effects of intrathecal NMDA, a glutamatergic agonist, and 2-amino-5-phosphonovaleric acid (AP-5), an NMDA receptor blocker, in both intact and late spinal cats. Low doses of NMDA had no major effect on the locomotor pattern in both intact and late spinal cats. Larger doses of NMDA in the chronic spinal cat initially produced an increase in the general excitability followed by more regular locomotion. AP-5 in intact cats caused a decrease in the amplitude of the flexion reflex and induced a bilateral foot drag as well as some decrease in weight support but it did not prevent locomotion. However, in late spinal cats, the same dose of AP-5 blocked locomotion completely. These results indicate that NMDA receptors may be critical for the spontaneous expression of spinal locomotion. It is proposed that the basic locomotor rhythmicity in cats is NMDA-dependent and that normally this glutamatergic mechanism is modulated by other neurotransmitters, such as 5-HT and NA.

The Response of Testes Cells to Low Level, Single dose Helium Particle Irradiation

1982 ◽  
Vol 40 ◽  
pp. 252-253
Author(s):  
D.E. Philpott ◽  
W. Sapp ◽  
C. Williams ◽  
J. Stevenson ◽  
S. Black ◽  
...  
Keyword(s):  
Stem Cell ◽  
Single Dose ◽  
B Cell ◽  
Cell Survival ◽  
Spermatogonial Stem Cell ◽  
Low Doses ◽  
Particle Irradiation ◽  
Stem Cell Survival ◽  
Irradiation Injury ◽  
Radio Sensitivity

Spermatogonial stem-cell survival after irradiation injury has been studied in rodents by histological counts of surviving cells. Many studies, including previous work from our laboratory, show that the spermatogonial population demonstrates a heterogeneous response to irradiation. The spermatogonia increase in radio-sensitivity as differentiation proceeds through the sequence As - Apr - A1 - A2 - A3 - A4 - In - B. The stem (As) cell is the most resistant and the B cell is the most sensitive. The purpose of this work is to investigate the response of spermatogonial cell to low doses (less than 10 0 rads) of helium particle irradiation.

Potentiation of bromotrichloromethane hepatotoxicity in male rats exposed to 10 ppm dietary chlordecone: Electron Microscopic and biochemical study

1990 ◽  
Vol 48 (3) ◽  
pp. 284-285
Author(s):  
O. M. Faroon ◽  
R. W. Henry ◽  
M. G. Soni ◽  
H. M. Mehendale
Keyword(s):  
Free Radical ◽  
Biochemical Study ◽  
Prior Exposure ◽  
Male Rats ◽  
Cellular Injury ◽  
Low Doses ◽  
Mixed Function Oxidase ◽  
Electron Microscopic ◽  
Potent Inducer ◽  
Cellular Energy

Previous work has shown that mirex undergoes photolytic dechlorination to chlordecone (CD) (KeponeR) in the environment. Much work has shown that prior exposure to nontoxic levels of CD causes potentiation of hepatotoxicity and lethality of CCl4, BrCCl3 and other halomethane compounds. Potentiation of bromotrichloromethane hepatotoxicity has been associated with compounds that stimulate the activity of hepatic mixed-function oxidase (MFO). An increase in the metabolism of halomethane by the MFO to a free radical initiates peroxidative decomposition of membranal lipids ending in massive cellular injury. However, not all MFO inducers potentiate BrCCl3 hepatotoxicity. Potentiation by much larger doses of phenobarbital is minimal and th at by a more potent inducer of MFO, mirex, is negligible at low doses. We suggest that the CD and bromotrichloromethane interaction results in a depletion of cellular energy and thereby reducing the cellular ability to undergo mitosis.

Low doses of pamidronate to treat osteopenia in children with severe cerebral palsy: a pilot study

2006 ◽  
Vol 48 (09) ◽  
pp. 709 ◽  
Author(s):  
Horacio Plotkin ◽  
Susan Coughlin ◽  
Rose Kreikemeier ◽  
Kathryn Heldt ◽  
Matias Bruzoni ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Pilot Study ◽  
Low Doses

Radiopharmacology: Hazard or/and Benefit

1984 ◽  
Vol 23 (02) ◽  
pp. 87-91 ◽  
Author(s):  
K. Flemming
Keyword(s):  
Ionizing Radiation ◽  
Late Effects ◽  
Radiation Risk ◽  
Dose Effect ◽  
Radiation Hazard ◽  
Radiation Doses ◽  
Low Doses ◽  
Medical Radiology ◽  
Experimental Findings ◽  
In The Beginning

SummaryIn the beginning of medical radiology, only the benefit of ionizing radiation was obvious, and radiation was handled and applied generously. After late effects had become known, the radiation exposure was reduced to doses following which no such effects were found. Thus, it was assumed that one could obtain an optimal medical benefit without inducing any hazard. Later, due to experimental findings, hypotheses arose (linear dose-effect response, no time factor) which led to the opinion that even low and lowest radiation doses were relevant for the induction of late effects. A radiation fear grew, which was unintentionally strengthened by radiation protection decrees: even for low doses a radiation risk could be calculated. Therefore, it was believed that there could still exist a radiation hazard, and the radiation benefit remained in question. If, however, all presently known facts are considered, one must conclude that large radiation doses are hazardous and low doses are inefficient, whereas lowest doses have a biopositive effect. Ionizing radiation, therefore, may cause both, hazard as well as benefit. Which of the two effects prevails is determined by the level of dose.

Involvement of 5-Hydroxytryptamine in Platelet Aggregation In Vivo in Rats and Guinea Pigs

1989 ◽  
Vol 61 (03) ◽  
pp. 463-467 ◽  
Author(s):  
G M Smith
Keyword(s):  
Platelet Count ◽  
Guinea Pigs ◽  
Platelet Adhesion ◽  
Adenosine Diphosphate ◽  
Rate Of Return ◽  
Low Doses ◽  
Dose Dependent ◽  
Higher Doses ◽  
Rat Platelets

SummaryIn this study, 5-hydroxytryptamine (5-HT) caused a dose- dependent fall in the circulating platelet count suggesting that 5-HT receptors are activated in rat platelets to cause platelet adhesion and aggregation. When low doses of adenosine diphosphate (ADP) were simultaneously injected with 5-HT, there was a significant potentiation of the responses to ADR Ketanserin significantly reduced the potentiated responses. When higher doses of ADP were infused with bolus injections of 5-HT there was no potentiation and ketanserin did not reduce these responses. Ketanserin did not inhibit the collagen-induced fall in circulating platelet count, but did significantly increase the rate of return to the basal platelet count compared with control. 5-HT did not cause a fall in platelet count in guinea-pigs

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