Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Slices of rabbit lung tissue (approximately 150 mg; 0.5 mm) were incubated in 5 ml of Krebs-Ringer phosphate buffer, in the presence of 0.25 mM [14C]chlorphentermine (CP) with shaking at 37 degrees C and under an atmosphere of an O2/CO2 mixture (95 : 5). Incubation medium (M) and tissue (T) were analyzed for radioactivity. Uptake of CP reached a plateau after 30 min at a T/M ratio of 20. Upon varying the concentration of [14C]CP from 0.125 mM to 2 mM, the concentration-response curve was seen to saturate and the T/M ratio decreased with increasing concentration. Substituting LiCl for NaCl or increasing the K+ content in the medium decreased CP uptake. Incubation of slices with Na+-pump inhibitors, harmaline and iodoacetate, significantly decreased CP uptake. Chloroamphetamine, desimipramine, imipramine, morphine, chlorpromazine, dieldrin, methadone, amphetamine (each at 1 mM) and incubation at 10 degrees C inhibited CP uptake. Imipramine and amphetamine were both effective in displacing previously accumulated CP from the tissue slices. Efflux of CP from the lung slices was biphasic and was not affected by removal of Na+ from the medium. Binding of CP to lung homogenate was unaffected by substituting LiCl for NaCl or by the presence of 1 mM iodoacetate. However, 1 mM harmaline or 1 mM imipramine decreased CP binding. These studies offer evidence for a partially Na+-dependent, active uptake process for pulmonary sequestration of CP compatible with earlier findings obtained with perfused intact lung preparations.
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PMID:Chlorphentermine uptake by rabbit lung slices. 741 14

Pentylenetetrazol (PTZ) and sodium valproate (VPA) produce acutely in the naive rat various behavioural effects resembling signs of opiate withdrawal in the morphine-treated subject. Suggestions in the literature that these substances may activate directly some of the neural consequences of opiate and drug withdrawal prompted us to look for and examine possible aversive effects of these substances at non-toxic doses. With a sensitive two-flavour, three-trial taste aversion procedure, relatively low doses of PTZ and VPA (5 and 160 mg/kg, respectively) do indeed have aversive effects. The maximum aversions were produced by 10 and 20 mg/kg PTZ and 320 mg/kg VPA and were equivalent to those of morphine withdrawal precipitated by 0.01-0.03 mg/kg naloxone in a morphine pellet-implanted animal. Moreover, the maximum aversions with PTZ and VPA were significantly higher than the maximum aversions seen with naloxone in the drug-naive animal under the same training conditions. Thus, the data from the present study confirmed the notion that low doses of PTZ and VPA in the naive animal may activate processes activated by drug withdrawal, including those important for the motivational effect of withdrawal. However, it was also pointed out that the lowest dose VPA producing aversion was higher than that found here to produce writhes and ataxia (80 mg/kg) but the same as that required for shaking (160 mg/kg), while the PTZ aversion was at a dose lower than that known to produce a PTZ cue. Implications were discussed for using withdrawal-like phenomena as a model in the non-treated organism of clinically-relevant withdrawal effects.
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PMID:Withdrawal-like effects of pentylenetetrazol and valproate in the naive organism: a model of motivation produced by opiate withdrawal? 758 68

To investigate the role of hydrogen peroxide in Cr(VI) toxicity in vivo toward bacterial cells, we examined the effect of Cr(VI), hydrogen peroxide, sodium azide, and mannitol on the viability of Escherichia coli. Bacterial cells were incubated for 1 h with shaking in the presence of Cr(VI), hydrogen peroxide, sodium azide as catalase inhibitor, and/or mannitol as radical scavenger. The colony-forming ability and double-strand DNA degradation were examined. The viability assays revealed that Cr(VI) toxicity depended on hydroxyl radicals generated in the reaction involving hydrogen peroxide and chromium. Moreover, incubation of E. coli cells with 10 mM Cr(VI) and 3 mM hydrogen peroxide caused the degradation of double-strand DNA in vivo, which was suppressed by the addition of mannitol. These results indicated that hydroxyl radicals generated in the incubation degraded DNA of E. coli cells, resulting in cell death. In the absence of added hydrogen peroxide, the intracellular concentration of hydrogen peroxide in E. coli was low (below 1 microM). A catalase-defective strain incubated in the absence of added hydrogen peroxide remained fully viable after 1 h but showed decreased viability after prolonged incubation (4-8 h). The addition of mannitol suppressed this decrease, suggesting that hydroxyl radicals may be involved in the expression of Cr(VI) toxicity even without added hydrogen peroxide.
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PMID:Mechanism of chromium(VI) toxicity in Escherichia coli: is hydrogen peroxide essential in Cr(VI) toxicity? 759 39

[3H]Aniracetam bound to specific and saturable recognition sites in membranes prepared from discrete regions of rat brain. In crude membrane preparation from rat cerebral cortex, specific binding was Na+ independent, was still largely detectable at low temperature (4 degrees C), and underwent rapid dissociation. Scatchard analysis of [3H]aniracetam binding revealed a single population of sites with an apparent KD value of approximately 70 nM and a maximal density of 3.5 pmol/mg of protein. Specifically bound [3H]aniracetam was not displaced by various metabolites of aniracetam, nor by other pyrrolidinone-containing nootropic drugs such as piracetam or oxiracetam. Subcellular distribution studies showed that a high percentage of specific [3H]aniracetam binding was present in purified synaptosomes or mitochondria, whereas specific binding was low in the myelin fraction. The possibility that at least some [3H]aniracetam binding sites are associated with glutamate receptors is supported by the evidence that specific binding was abolished when membranes were preincubated at 37 degrees C under fast shaking (a procedure that substantially reduced the amount of glutamate trapped in the membranes) and could be restored after addition of either glutamate or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) but not kainate. The action of AMPA was antagonized by DNQX, which also reduced specific [3H]aniracetam binding in unwashed membranes. High levels of [3H]aniracetam binding were detected in hippocampal, cortical, or cerebellar membranes, which contain a high density of excitatory amino acid receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[3H]aniracetam binds to specific recognition sites in brain membranes. 761 53

Single-vacancy models have been proposed as open channel permeation mechanisms for K+ channels. Single-ion models have been used to describe permeation through Na+ channels. This paper demonstrates that these models have a distinctive symmetry property. Their permeability ratios, measured under biionic conditions, are independent of channel orientation when the reversal potential is zero. This symmetry is a property of general m-site single-vacancy channels, m-site shaking-stack channels, as well as m-site single-ion channels. An experimental finding that the permeability ratios of a channel did not have this symmetry would provide evidence that a single-vacancy or single-ion model is an incorrect or incomplete description of permeation.
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PMID:Orientation independence of single-vacancy and single-ion permeability ratios. 766 13

A 69-year-old woman was admitted because of severe dehydration due to anorexia. Consciousness disturbance was found to be due to severe abnormalities of serum electrolyte balance, but recovered quickly by correcting the hyperosmolality. While the initial serum sodium value of 186 mEq/L was corrected to 139 mEq/L in 5 days, locked-in syndrome, bilateral hand tremor and tetraparesis appeared. Brain magnetic resonance imaging (MRI) revealed symmetrically high signal intensity areas on T2-weighted images and low signal intensity areas on T1-weighted images in central part of pons and bilateral middle cerebellar peduncles. One and a half month later, these neurologic symptoms were improved and the MRI abnormalities also disappeared. Auditory brain stem responses which showed prolongations of III to V wave peak to peak latency at the onset returned to normal. It is noted in this case that central pontine myelinolysis (CPM) and extrapontine myelipolysis (EPM) appeared during the period of rapid correction of hypernatremia. Although it is known CPM and EPM are caused by hypernatremia or the rapid correction of hyponatremia, there has been reported only one case of CPM and EPM after rapid correction of hypernatremia. According to the hypothesis of Norenberg, rapid rise in serum sodium may cause CPM and EPM, but if CPM and EPM are caused by the rapid correction of hypernatremia in this case, CPM and EPM may be caused by another pathogenesis of the disorder.
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PMID:[A case of central pontine myelinolysis and extrapontine myelinolysis during rapid correction of hypernatremia]. 772 94

1. Two types of nylon-6 supports (small cylinders and a sponge-like derivative) were prepared for immobilizing enzymes. Nylon-6 beads were solubilized by immersion in 80% formic acid and then reprecipitated using two different types of non-solvent solutions (distilled water or a 1:1 acetone:water solution) giving rise to a sponge-like derivative and to a colloidal suspension, respectively. The latter was molded into a thin thread which was cut into small cylinders. 2. Trypsin (EC 3.4.21.4) was covalently bound to glutaraldehyde-activated nylon-6 cylinders as well as to the sponge-like derivative. The maximum (100%) apparent initial enzymatic activity was found for the trypsin bound to small cylinders, while the initial activity of trypsin bound to the sponge-like material was 61% in comparison with that of trypsin-small cylinders, under the same conditions of enzyme immobilization reaction (1 g of nylon support and 5 ml of 1.3 mg/ml trypsin in 0.1 M sodium phosphate buffer, pH 8.5, at 10 degrees C for 18 h) and of enzymatic reaction (1 g of trypsin-nylon in a batch reactor, 2 ml of 0.7% w/v azocasein solution in 50 mM borate buffer, pH 8.5, at 37 degrees C, with shaking, for 1 h). However, the decrease of activity after enzyme immobilization was more conspicuous for the trypsin-small cylinders than for the trypsin-sponge. The former retained approximately 25% of its initial activity, while the latter retained approximately 67% of its initial activity, after seven cycles of utilization for 1 h, pH 8.5, at 37 degrees C and 8 days of storage, pH 8.5, at 4 degrees C in the presence of azocasein. 3. Scanning electron microscopy was performed to visualize the surface of the support after each step of the immobilization process. The electron micrographs show that the two types of nylon supports had a rough surface, which became rougher and full of craters after treatment with 5 N HCl. On the other hand, the partially hydrolyzed nylon surface acquired the appearance of Swiss cheese after treatment with 2.5% glutaraldehyde. After reaction with the enzyme molecules the surface became rougher again.
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PMID:Nylon-6 cylinders and a sponge-like derivative as supports for immobilizing trypsin. 787 18

Efficient methods for the recovery of genetically engineered organisms (GEM) added to soil are critical if the safety of potential releases is to be evaluated and the actual release is to be monitored. Pseudomonas aureofaciens strain 3732 RN-L11 (lacZY) was added to 10 g sieved soil microcosms and incubated for 5 and 28 days. Various diluents, shaking methods, and settling of soil were examined to determine the optimum method for recovery of the GEM from the soil. Of the diluents examined, 0.1% agar gave significantly lower numbers than distilled water, 1.0% sodium metaphosphate, 1% peptone, and phosphate-buffered water. After 5 days of incubation, shaking for 10 min with glass beads and shaking for 30 min without glass beads resulted in the highest recovery of the GEM from soil, while sonification resulted in the lowest recovery. After 28 days of incubation, sonification produced significantly lower numbers than any of the other treatments. The addition of 1% CaCl2 to enhance settling significantly increased recovery efficiency. Although the use of CaCl2 in distilled water and shaking for 10 min was an effective method for recovering P. aureofaciens from a Maryland soil, when the same extraction procedure was compared with a standard technique (dd H2O, shaking for 10 min) for eight divergent soils, neither extraction method was consistently better than the other. Statistical analysis of the data showed the need for log transformation of the raw data. Four microcosm and two plate replicates for each dilution provided the greatest ability to detect differences between treatment means while maximizing experimental efficiency.
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PMID:Pseudomonas aureofaciens in soil: survival and recovery efficiency. 792 53

Leydig cells were isolated from adult male guinea-pig testes using a multi-step procedure involving enzymatic dissociation and Percoll-gradient centrifugation. The following description is the first account of a successful isolation of adolescent guinea-pig Leydig cells. The enriched Leydig-cell preparation routinely isolated from six intact testicles yielded approximately 5.0 x 10(6) +/- 0.7 x 10(6) (+/- SEM) Leydig cells with a viability of 98.0 +/- 0.4% as determined using the trypan-blue exclusion method. The purity of the isolated cell population as assessed by 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) staining averaged 82.5 +/- 0.8%. Under light microscopy, guinea-pig Leydig cells were polyhedral in shape with a large prominent nucleus and a distinct nucleolus. The acidophilic cytoplasm contained numerous lipid-filled vesicles. Ultrastructurally, guinea-pig Leydig cells displayed an eccentrically located ovoid nucleus with dark-staining peripheral heterochromatin. Large quantities of mitochondria, smooth endoplasmic reticulum and particulate-laden lipid droplets were also evident. The steroidogenic potential of the isolated Leydig cells was verified using a maximally stimulating dose of ovine LH (100 ng ml-1) and human CG (200 mIU ml-1). Leydig cells incubated in a shaking (120 cycles min-1) water bath for 3 h at 37 degrees C in capped polypropylene microcentrifuge tubes produced 233 +/- 21 ng and 223 +/- 18 ng testosterone per 1 x 10(6) cells when maximally stimulated with oLH or hCG, respectively. The inclusion of low (1-5 microM) levels of sodium ascorbate during culture enhanced significantly Leydig-cell viability vs. control values.
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PMID:Isolation and culture of highly enriched populations of Leydig cells from guinea-pig (Cavia porcellus) testes. 797 73

A primer-directed DNA amplification polymerase chain reaction assay for detection of seed contaminated with highly virulent Leptosphaeria maculans was developed. The primers were derived from a 5,238-bp repetitive sequence present only in the highly virulent isolates of the fungus. A procedure for isolating DNA from organisms infesting germinating seed was also developed. Seeds were added to liquid fungal minimal medium, and the culture was incubated for 3 days at room temperature with shaking. The organisms were collected from the cultures by centrifugation and lysed with a combination of sodium dodecyl sulfate and proteinase K. The DNA was extracted with organic solvents and with a high-salt-cetyltrimethylammonium bromide solution. It was also precipitated with a low-salt-cetyltrimethylammonium bromide solution. The extensive treatments used for minimizing polysaccharide contamination greatly improved the reliability of the assay. The minimum contamination level (2 of 1,000 seeds) that was tested was successfully detected with this DNA isolation procedure. The reliability of the assay was 96% at the 1 to 2% level of seed contamination. The described method is less laborious and requires only 4 to 5 days for completion in comparison to the 11 to 22 days required for the currently employed methods. In addition, large sample sizes can be easily handled, thus reducing the probability of contaminated seed escaping detection.
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PMID:A simple, sensitive, and rapid method for detecting seed contaminated with highly virulent Leptosphaeria maculans. 828 76


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