Gene/Protein Disease Symptom Drug Enzyme Compound
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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mivacurium is a new short-acting competitive neuromuscular blocking agent. Infusion requirements for the maintenance of a stable 90-99% muscle twitch depression were determined in 28 children anaesthetized with nitrous oxide and 1% halothane (inspired) in oxygen or nitrous oxide in oxygen and opioid. Neuromuscular block was assessed by monitoring the force of contraction of the adductor of the thumb during train-of-four (TOF) stimulation at 0.1 Hz. Infusion rate and twitch depression were analysed from 15 to 75 min and from 75 to 135 min after the start of the infusion. In the first period of evaluation, the mean infusion requirement was 10.4 (SEM 0.92) micrograms kg-1 min-1 during the halothane anaesthesia and 13 (1.4) micrograms kg-1 min-1 during the opiod anaesthesia (P less than 0.05). This difference was present also during the second 60-min period. There was no significant correlation between infusion rates required to maintain greater than 90% depression of the first twitch (T1) of the TOF and plasma cholinesterase concentrations. Regardless of the anaesthetic regimen, children recovered rapidly after discontinuing the infusion. The recovery index (25-75% recovery of T1) for all patients was 5.4 (0.57) min with no significant differences between the groups.
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PMID:Continuous infusion of mivacurium in children. 253 33

The two parameters of the active [methyl-3H]choline uptake into isolated rat forebrain microvessels, Km and Vmax, were determined for 1-, 3-, 10-, and 24-month-old Charles River male rats and compared with the activities of the enzymes choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) in these microvessels over the same time course. The value of Km remained constant over the entire period, but that of Vmax increased from 8.5 +/- 1.0 to 80.6 +/- 16.4 nmol g-1 (mean +/- SEM) over the first 3 months of life. Over the same period, the increase in ChAT activity, from an initial value of 7.1 +/- 1.6 to 10.2 +/- 0.3 nmol g-1 min-1, was not proportional to that of choline uptake. Levels of BuChE activity (0.9-1.3 mumol g-1 min-1) were almost unchanged throughout the entire 24-month period, but those of AChE showed a steady and significant increase from 1 to 24 months, remaining relatively high at senescence (4.7 mumol g-1 min-1), when choline uptake had decreased to one-third of its optimal value. Selective inhibition of AChE with 1,5-bis(4-allyldimethylammonium-phenyl)pentan-3-one dibromide (0.5 microM) in unruptured capillaries from 3-month-old rats resulted in a decrease in Vmax of choline uptake from approximately 81 to 59 nmol g-1 min-1 or with 9-amino-1,2,3,4-tetrahydroacridine (10 microM) in capillaries from 2-month-old rats from approximately 30 to 15 nmol g-1 min-1. Selective inhibition of BuChE with tetraisopropyl pyrophosphoramide (100 microM) resulted in an increase in Vmax from approximately 81 to 96 nmol g-1 min-1. It is possible that the two vascular enzyme systems are coupled to a hypothetical endothelial choline transporter, but with an action opposite to each other.
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PMID:Vascular cholinesterases and choline uptake in isolated rat forebrain microvessels: a possible link. 274 36

Mivacurium chloride (BW B1090U) is a new, short-acting non-depolarizing neuromuscular blocking agent. It is a synthetic bis-benzylisoquinolinium diester, which is hydrolysed rapidly by plasma cholinesterase. This study compares mivacurium, atracurium and vecuronium by continuous i.v. infusion. The duration of mivacurium infusion ranged from 29.5 to 286 min. The steady state infusion rates necessary to maintain 95 (SEM 4)% twitch suppression were: mivacurium 8.3 (0.7) micrograms kg-1 min-1; atracurium 7.9 (0.4) micrograms kg-1 min-1; vecuronium 1.2 (0.3) micrograms kg-1 min-1. Following infusions of mivacurium, various recovery times (for example: 25-75%, 6.9 (0.3) min; 25-95%, 11.0 (0.4) min; 5-95% 14.5 (0.4) min) did not differ significantly from those following single bolus doses. Recovery times following cessation of mivacarium infusions were approximately 50% of those for equivalent durations of infusion of atracurium (10.9 (0.3) min for 25-75% recovery and 26.6 (0.4) min for 5-95% recovery). For vecuronium, corresponding recovery times were 13.8 (0.9) and 32.0 (1.2) min, respectively. Comparative recovery times for mivacurium were 40-50% of those for vecuronium. There was a significant correlation between the infusion rate of mivacurium required to maintain 95% twitch depression and the plasma cholinesterase activity of individual subjects.
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PMID:Clinical pharmacology of mivacurium chloride (BW B1090U) infusion: comparison with vecuronium and atracurium. 290 43

Gibbon interleukin-3 (rIL-3) has recently been cloned and found to have a high degree of homology with the human IL-3 molecule. In this investigation, we evaluated the effects of gibbon rIL-3 on normal human peripheral blood megakaryocyte progenitor cell growth in vitro. Gibbon rIL-3 exhibited substantial megakaryocyte colony stimulatory activity (Meg-CSA), supporting peak colony numbers at a concentration of 1 U/ml. Megakaryocyte colony growth induced by rIL-3 reached 58% of the maximum achieved with the active, Meg-CSA-containing protein fraction of aplastic canine serum. Increasing gibbon rIL-3 concentrations also stimulated a 4-5-fold increase in megakaryocyte colony size and resulted in a decrease in geometric mean megakaryocyte ploidy. Ploidy values fell from 8.5N +/- 1.4 (+/- SEM) at an rIL-3 concentration of 0.1 U/ml to a minimum of 2.9N +/- 0.3 at 10 U/ml. In the presence of rIL-3 at 1.0 U/ml, megakaryocyte colony growth was linear with cell plating density and the regression line passed approximately through the origin. The effects of rIL-3 on megakaryocyte colony growth were independent of the presence of T-lymphocytes in the cultures. Cross-species evaluation of murine and gibbon IL-3 indicated that its bioactivity is species restricted. Murine IL-3 did not support colony growth from human megakaryocyte progenitors and gibbon rIL-3 showed no activity in stimulating acetylcholinesterase production by murine bone marrow cells. Gibbon rIL-3 is a potent stimulator of the early events of human megakaryocyte progenitor cell development promoting predominantly mitosis and early megakaryocytic differentiation.
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PMID:Recombinant gibbon interleukin-3 stimulates megakaryocyte colony growth in vitro from human peripheral blood progenitor cells. 326 19

Blood samples were drawn from 10 ASA physical status 1 and 2 patients before (baseline) and after the administration of cimetidine to determine the in vivo effect of cimetidine on plasma cholinesterase (PCHE) activity. The in vitro effects of cimetidine at different plasma concentrations were also studied using the same blood samples. PCHE activity in the baseline samples was 432 +/- 4.6 (mean +/- SEM) U/ml, the dibucaine number 82. Administration of oral cimetidine (300 mg) the night before and 2 hours before surgery, failed to have any effect on PCHE activity (no in vivo effect). Plasma cholinesterase activity in the presence of cimetidine in vitro at plasma concentrations of 1.5, 15, 150, and 1500 micrograms/ml was 428, 420, 397, and 177 U/ml, respectively. Thus, in vitro data showed that cimetidine at plasma concentrations (1.5 to 15 micrograms/ml) achieved with clinical doses also has no effect on PCHE activity.
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PMID:Cimetidine does not affect plasma cholinesterase activity. 333 48

Human ejaculates were divided into 3 groups (I, II and III) according to the extent of their coagulation and the levels of free choline and cholinesterase were determined together with seminal vesicular N-acetylamino sugar and prostatic (zinc) marker components. Coagulation was determined as the percent coagulum (CG) at 5 min after ejaculation. The mean (+/- SEM) values for CG at 5 min in groups I, II and III were 6 +/- 2, 43 +/- 4 and 79 +/- 2, respectively. The time for 100% liquefaction in the 3 groups were 4.7 +/- 0.8, 12.9 +/- 1.4 and 19.1 +/- 2.1 min, respectively. Group III had significantly higher levels of choline and cholinesterase activity than groups I and II. The choline level was correlated significantly (r = 0.58) with the concentration of N-acetylamino sugar, but there was no correlation with the level of zinc. Evaluation of the level of choline in prostatic fluid, in semen from azoospermic men and in ejaculates with different CG values suggested that the level of choline may provide valuable information about activity of the seminal vesicles. Release of choline in group I was only 33 and 50% of that groups III and II, respectively. 60% of the total release of choline occurred during the liquefaction phase. The mean activity of cholinesterase in the prostate was only 27% lower than that found in seminal plasma. The liquefaction time and the concentration of choline, N-acetylamino sugar and zinc decreased significantly in ejaculates after 2 days of abstinence.
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PMID:Grouping of human ejaculates according to the degree of coagulation and the relationship to the levels of choline and cholinesterase. 357 May 33

The role of hypothermia in the antihypoxic effects of drugs was examined in the present experiments. The effects of environmentally induced hypothermia and drugs were tested by exposing mice to 100% nitrogen gas for 80 sec and counting the number of survivors. In a series of 68 vehicle control groups, the mean of mice surviving the test was 8.6% (SEM = 1.4). Hypothermia induced by lowering the ambient temperature or by isolating mice for a brief period increased the number surviving hypoxia, and the per cent of animals surviving was linearly related to body temperature. When the effects of drugs were compared to that of hypothermia, several drugs were found which protected mice from hypoxia to a greater extent than hypothermia alone. Active substances included the anticonvulsant drugs phenobarbital, phenytoin, carbamazepine and diazepam, but not primidone. Physostigmine and the muscarinic agonist oxotremorine also caused significant protection, while the effects of nicotine could be completely accounted for by hypothermia. Arecoline had a biphasic, time-dependent effect that may be explained by a combination of muscarinic and nicotinic actions. The effects of the muscarinic agonists are centrally mediated, since they could be blocked by low doses of scopolamine HCl, but not by the quaternary analog scopolamine methyl nitrate. Furthermore, the antihypoxic effect of physostigmine was not mimicked by the peripherally acting acetylcholinesterase inhibitor, neostigmine. These results suggest that some drugs do have protective effects against hypoxia which are independent of drug-induced hypothermia and that these effects may be mediated through the CNS.
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PMID:Protection against hypoxia-induced lethality in mice: a comparison of the effects of hypothermia and drugs. 359 68

Long-Evans male adult rats were intermittently exposed for 14 weeks to continuous wave (CW) 2450-MHz microwaves at an average power density of 2.5 mW/cm2. The mean specific absorption rate was 0.70 W/kg (+/- 0.02 SEM). The rats were exposed 7 h/day, 7 days/week in a radiation chamber with a monopole above ground, while housed in Plexiglas cages. Weekly measures of body mass and food intake did not indicate statistically significant effects of microwave irradiation. Assessments of threshold for electric-footshock detection revealed a significant difference between microwave and sham-exposed animals. Assessments of cholinesterase and sulfhydryl groups in blood and 17-ketosteroids in urine did not distinguish the two groups of rats. Behavioral measures made at the end of the 14-week exposure included an open-field test, shuttlebox avoidance performance, and schedule-controlled lever-pressing for food pellets. Statistically significant differences between microwave- and sham-exposed rats were observed for these measures. Examination of adrenal tissue, plasma electrolytes, and organ masses after 14 weeks of exposure revealed no difference between the two groups of rats.
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PMID:Intermittent exposure of rats to 2450 MHz microwaves at 2.5 mW cm2: behavioral and physiological effects. 375 34

When murine (C57BL/6) bone marrow cells are cultivated with WEHI-3 conditioned media, a source of megakaryocyte-colony-stimulating activity (Mk-CSA), and phorbol myristate acetate (PMA), a previously undetected population of megakaryocyte (Mk) progenitor cells is observed. These new Mk colonies are reminiscent of erythroid bursts, in that they contain large numbers (40-500) of Mk and multiple foci (2-7) of development. These burst-forming units, Mk (BFU-Mk), are defined as having greater than or equal to 42 cells/colony and, at least, three foci of Mk development (colonies grown in soft agar cultures, all studies done at limiting dilutions; colonies detected by acetylcholinesterase [ACh-E] staining). CFU-Mk and BFU-Mk require two activities for optimal growth: Mk-CSA and PMA. However, the BFU-Mk require a tenfold greater concentration of PMA for optimal development (10(-6) vs. 10(-7) M). BFU-Mk detection is linear (over a range of 25-100 X 10(3) cells/ml), with the regression line passing through the origin. Bone marrow frequencies of these two progenitor cells are CFU-Mk, 36.7 +/- 2.5, and BFU-Mk, 7.3 +/- 0.7 per 10(5) total nucleated cells (mean +/- SEM; n = 28). The BFU-Mk have a restricted velocity sedimentation range (3.3-4.5 mmh-1 vs. 3.3-6.8 mmh-1 for CFU-Mk). Modal buoyant densities are 1.068 +/- 0.0002 and 1.070 +/- 0.002 for BFU-Mk and CFU-Mk, respectively. Thus, these cells are found among the smallest and less dense of the Mk progenitors, and are not clumps or clusters of CFU-Mk. Kinetic analysis indicates that CFU-Mk require 5-7 d for optimal growth, whereas BFU-Mk require 10-12 d. Examination of the proliferative potential (cells per colony) shows 19.3 +/- 1.5 cells per colony (n = 246 colonies) for day 10 CFU-Mk, vs. 118 +/- 6.0 for day 10 BFU-Mk (n = 163). Analysis of the cellularity/subcolony within each burst indicates 37.0 +/- 2.1 (n = 146) Mk/colony and 3.9 +/- 0.1 subcolonies/burst (n = 100). Finally, greater than 90% of the BFU-Mk contain only ACh-E positive cells, indicating that these are not mixed colonies. These results indicate that the BFU-Mk, compared with the CFU-Mk, require an increased amount of stimulation in order to differentiate, show delayed in vitro development, and have a higher proliferative potential. These data are consistent with the hypothesis that these cells are early progenitor cells in the Mk lineage that antedate the CFU-Mk.
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PMID:Phorbol diesters stimulate the development of an early murine progenitor cell. The burst-forming unit-megakaryocyte. 387 29

To determine the neurotoxic effects of organophosphorus compounds in turkeys, adult birds were given a single oral dose of 125, 250, 500 mg/kg triorthotolyl phosphate (TOTP) or a single subcutaneous dose of 0.4 mg/kg O,O'-diisopropyl phosphorofluoridate (DFP). At 24 h after dosing with TOTP, neurotoxic esterase activity was found to be inhibited in a dose-related manner, as were the activities of blood cholinesterase and liver cholinesterase. Clinical signs of neuropathy appeared within 2 wk in TOTP-treated groups of birds with neurotoxic esterase activities at 59 +/- 3% (125 mg/kg), 47 +/- 7% (250 mg/kg) and 33 +/- 3% (500 mg/kg) of control values (mean +/- SEM, n = 5) at 24 h after dosing. Signs appeared earlier in turkeys given DFP. Histological examination revealed only mild lesions of delayed neurotoxicity in birds given either TOTP or DFP.
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PMID:Effect of neurotoxic organophosphorus compounds in turkeys. 395 18


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