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)

Ester synthesis catalyzed by Candida cylindracea lipase (triacylglycerol acylhydrolase, EC 3.1.1.3) was investigated in solid/liquid biphasic media containing the enzyme preparation and reactants without addition of organic solvents not participating in the reaction. Although the effects of water on enzyme kinetics have been abundantly studied in nearly anhydrous media, reactions in which water is produced have not been investigated. The effect of water produced by the reaction itself on the enzymatic activity was studied. The dispersion of water in a shaken, nearly anhydrous medium was shown to be responsible for the lack of activity of the enzyme. In contrast, when slowly shaken, the enzyme was fully activated by the water furnished as a product of the reaction. However, when experiments were performed in a two-phase aqueous/organic system with previously solubilized enzyme in water, the enzyme activity was increased by shaking and was of the same order of magnitude as in nearly anhydrous media. Under low water activity conditions, a powerful agitation can lead to slower reaction rate, because water, a product of esterification, is not retained in the microenvironment of the enzyme to activate it. The activation effect of water produced by the reaction was clearly shown using enzyme preparations shaken in an anhydrous medium and previously equilibrated at low water activities (aw = 0.13 and 0.69). This activation did not occur for an enzyme preparation equilibrated at high aw (0.89) or for a preparation gently shaken in a water-saturated medium. The lag time preceding activation of the enzyme increased with the extent of enzyme dehydration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Water activity as a key parameter of synthesis reactions: the example of lipase in biphasic (liquid/solid) media. 136 61

A microbial surfactant (biosurfactant) was investigated for its potential to enhance bioavailability and, hence, the biodegradation of octadecane. The rhamnolipid biosurfactant used in this study was extracted from culture supernatants after growth of Pseudomonas aeruginosa ATCC 9027 in phosphate-limited proteose peptone-glucose-ammonium salts medium. Dispersion of octadecane in aqueous solutions was dramatically enhanced by 300 mg of the rhamnolipid biosurfactant per liter, increasing by a factor of more than 4 orders of magnitude, from 0.009 to > 250 mg/liter. The relative enhancement of octadecane dispersion was much greater at low rhamnolipid concentrations than at high concentrations. Rhamnolipid-enhanced octadecane dispersion was found to be dependent on pH and shaking speed. Biodegradation experiments done with an initial octadecane concentration of 1,500 mg/liter showed that 20% of the octadecane was mineralized in 84 h in the presence of 300 mg of rhamnolipid per liter, compared with only 5% octadecane mineralization when no surfactant was present. These results indicate that rhamnolipids may have potential for facilitating the bioremediation of sites contaminated with hydrocarbons having limited water solubility.
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PMID:Enhanced octadecane dispersion and biodegradation by a Pseudomonas rhamnolipid surfactant (biosurfactant). 144 63

Repeated measurements of regional cerebral blood flow (rCBF) were obtained in 7 patients who underwent a stereotactic thalamic electrode implantation in the nucleus ventralis intermedius (nVIM) of the thalamus for severe hemi-parkinsonian tremor. Using positron emission tomography and oxygen-15 labelled water, rCBF was studied in each patient in two conditions: in absence of tremor, e.g. under nVIM electrical stimulation, and in presence of tremor. X-ray tomograms permitted individual definition of anatomical regions of interest. In presence of tremor, normalized rCBF increases were observed in the following regions: postcentral (13.6 +/- 8.4%, P = 0.0003), precentral (7.7 +/- 8.8%, P = 0.016), paracentral (7.7 +/- 8.4%), supplementary motor (8.2 +/- 10.4%, P = 0.025), caudate nucleus (5.7 +/- 7.6%, P = 0.03), vermis (9.7 +/- 7.3%, P = 0.007), cerebellar grey nuclei (9 +/- 6%, P = 0.016) on the electrode side and on the contralateral vermis (17.8 +/- 7.5%, P = 0.0003) and cerebellar grey nuclei (22 +/- 6.3%, P = 0.0004). These results clearly indicate an activation of the sensory-motor cortex, as well as an involvement of the supplementary motor area and the cortico-cerebellar pathways in Parkinsonian resting tremor (PRT). They demonstrate that PRT shares common network of brain structures with repetitive voluntary movement.
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PMID:Evidence for a common network of brain structures involved in parkinsonian tremor and voluntary repetitive movement. 151 31

The combined effect of the salivary peroxidase system and lysozyme on the glucose uptake of Streptococcus mutans NCTC 10449 was investigated. The bacteria were grown to late-exponential phase, washed, re-suspended in buffer at pH6, and incubated with (1) 50 micrograms/mL lysozyme from human milk for 60 min; (2) 7-15 mumol/L hypothiocyanous acid/hypothiocyanite for 10 min; and (3) lysozyme for 60 min prior to addition of and incubation with hypothiocyanous acid/hypothiocyanite for 10 min. Glucose uptake was initiated by adding the bacterial suspensions to 10 mL of pre-warmed 50 mumol/L glucose containing 0.98 mumol/L D-(U-14C-)-glucose, and the mixture was incubated in a shaking water-bath at 37 degrees C. Samples were withdrawn at various time intervals, rapidly filtered through 0.45-microns membranes, washed with ice-chilled buffer, and the incorporated radioactivity determined. Lysozyme stimulated S. mutans glucose uptake slightly, but significantly inhibited S. rattus glucose metabolism. A 20-30% inhibition of radiolabeled glucose incorporation was observed with hypothiocyanous acid/hypothiocyanite alone. Incubation of the bacteria with lysozyme prior to addition of hypothiocyanous acid/hypothiocyanite containing peroxidase resulted in a total inhibition of the glucose uptake. In contrast, lysozyme in combination with hypothiocyanous acid/hypothiocyanite without peroxidase gave only a 30-50% inhibition. The addition of 5 mmol/L dithiothreitol after incubation with lysozyme and hypothiocyanous acid/hypothiocyanite eliminated the inhibition of the bacterial glucose uptake. The viability of S. mutans was not affected by treatment with any of the components used. Our results indicate that physiological concentrations of lysozyme and the salivary peroxidase system components have a synergistic effect which results in a significant inhibition of glucose metabolism by S. mutans.
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PMID:Lysozyme enhances the inhibitory effects of the peroxidase system on glucose metabolism of Streptococcus mutans. 157 81

A behavioral mutant was found in the laboratory-bred musk shrew (Suncus murinus). The affected shrews were characterized by the behaviors of tight circling in both directions and frequent head shaking in horizontal. They could definitely be identified by at least day 10 after birth. These abnormal behaviors were steady and permanent through life. Mating experiments demonstrated that the mutant character is expressed by a single autosomal recessive gene in homozygote with complete penetrance. The pedigree analysis indicated that the gene was derived from one heterozygous male captured in Ginowan city, Okinawa. The name, waltzing, was proposed for this mutant character with the gene symbol wz. An abnormality of the balance organ was predicted for a cause of the abnormal behaviors, since, besides the circling and head shaking behaviors, the affected shrews could not keep the body stretching but twisted it frequently when they were held up by the tail and further they could not keep the head on the water surface at all. Nevertheless, the affected shrews were almost normal in gestation period, litter size, weaning ratio and body weight in comparison with the phenotypically normal ones. The mutant shrews have been maintained as a closed colony, the WZ line involved more than 30 individuals at every one generation.
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PMID:Inheritance and breeding of the waltzing mutant in the musk shrew (Suncus murinus, Insectivora) characterized by the circling and head-shaking behaviors. 157 73

Gamma interferon from genetic recombination (IFN) has been found to have an optimal pH at about 7. An increase in IFN concentration may cause a decrease in solution clarity. A proper selection of isotonizing agent, as well as the addition of sugars, is effective in improving the clarity. The amount of IFN adsorbed on filter membranes varies with the membrane materials: cellulose acetate adsorbs much IFN, 2-fluorovinylidene is the next, followed by polysulfon, and polycarbonate adsorbs it least of all materials tested. Stainless steel adsorbs little IFN, and the level can be lowered even more by electropolishing. Silicone coating can decrease the amount adsorbed to about 1 microgram per vial of 10 ml. The effect of pressure given to the IFN solution during filtration is negligible. Transfer of IFN solution through pipings of conventional shape may result in partial deactivation by bubbling. At around pH 7, a lower pH of IFN solution causes a higher moisture level of the freeze-dried product. Moisture levels up to 3% have no effect on IFN stability. Upon reconstitution of freeze-dried IFN by vigorous shaking with distilled water, filtration of the solution may become difficult because polymers might have been formed during vigorous shaking. The addition of L-cysteine, maltose, and human serum albumin, has been found to be as effective in preventing such unfavorable reactions. Fatty acids in human serum albumin, which is effective in stabilizing IFN, has been found to participate in preventing denaturation of human serum albumin upon freezing and freeze-drying; however, the denaturation prevention mechanisms are not clear yet.
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PMID:Freeze-drying and quality evaluation of protein drugs. 159 81

To study the development of acute pancreatitis after intraductal trypsin instillation, at 4 hours, 1, 2, 4 and 6 days after this treatment and after instillation of physiologic saline viable acinar cells were isolated from rat pancreas. Gross anatomic and histologic findings were used to evaluate the time course of pathomorphologic changes. The isolated cells were incubated at 37 degrees C in Eagle's medium in a shaking water bath and the time course of their damage was studied. Additionally, by means of the active accumulation of the fluorophore rhodamine 6 G alterations of the mitochondrial membrane potential, an important parameter of the cellular energy metabolism was evaluated. The most severe histological damage was seen 1 and 2 days after trypsin instillation. At the same time yield and survivability of cells isolated, and their mitochondrial membrane potential reached a minimum. In the controls the time course of these parameters was very similar, but their decrease was less pronounced. Since a direct action of trypsin on acinar cells cannot be responsible for the findings presented a possible involvement of inflammatory cells and their products in the alteration of the cells and of their energy metabolism must be considered.
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PMID:Influence of trypsin-induced acute pancreatitis on survival and energy state of isolated acinar cells from rat pancreas. 159 92

The stability of captopril in tap water was studied. Twenty 25-mg captopril tablets were crushed separately, added to 25 mL of tap water in individual volumetric flasks, and shaken vigorously. Five flasks each were incubated at 25, 50, and 75 degrees C in a shaking water bath and refrigerated at 5 degrees C. Samples were taken from each flask immediately after dissolving the drug and at intervals up to 28 days for 5 and 25 degrees C, 15 days for 50 degrees C, and 16 days for 75 degrees C. Captopril concentrations were analyzed by high-performance liquid chromatography. First-order rate constants were calculated for each temperature setting, and the Arrhenius plot was applied to estimate the shelf life of captopril at 5 degrees C. More than 90% of the initial concentration of captopril remained after 28 days at 5 degrees C. Captopril concentration in the samples stored at 75, 50, and 25 degrees C decreased to 90% of the initial concentration at calculated times (mean +/- S.E.) of 2.1 +/- 0.1, 3.6 +/- 0.4, and 11.8 +/- 1.2 days, respectively. The estimated time required for the concentration of a 1-mg/mL solution of captopril stored at 5 degrees C to decrease to 90% of initial concentration was 27 days. The shelf life of a solution of captopril 1 mg/mL in tap water stored at 5 degrees C was 27 days.
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PMID:Stability of captopril in tap water. 159 37

Aqueous gels of two analogous, water-insoluble copolymers A and B have been formed by addition of excess water to concentrated ethanol solutions of the polymers. A and B differed only in their content of cationic groups in a ratio 2:1 (A:B). The gels were converted permanently to fluids (i.e. gel-sol transformation) at high shear rates. Stability of the resulting polymer dispersions depended on the presence and mutual repulsion of the polymer cations. Polymer B dispersions were less stable to the flocculating effect of an electrolyte (sodium chloride). At certain critical concentrations, 0.2 M NaCl (for polymer A), or 0.1 M NaCl (for polymer B) the electrolyte flocculated the otherwise stable dispersions to a gel structure. The electrolyte-flocculated gels were readily redispersed to fluids by shaking but reverted to gels on standing (thixotropic). In contrast the original coacervated gels (without electrolyte) could not be redispersed easily with manual shaking. Lower polymer-polymer interaction in the thixotropic system relates possibly to increases in particle size and irregularity of particle shape during flocculation.
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PMID:Thixotropic phenomenon in flocculated aqueous dispersions of acrylate methacrylate copolymers. 167 78

Studies were undertaken to determine the effects of 2-hydroxypropyl-beta-cyclodextrin (HPCD) on the solubility of ovine-Growth Hormone (o-GH) in aqueous solution. HPCD, which is believed to form inclusion complexes with hydrophobic amino acid residues of peptides, markedly increased o-GH solubility at all o-GH and all HPCD concentrations tested. In HPCD solutions, o-GH was completely solubilized between pH 7.5 and 8.5, while in water, o-GH was not solubilized until a pH of 11.5 was reached. Temperature and repeated freeze-thaw cycles had little effect on o-GH solubility in HPCD. Vigorous shaking of solution of o-GH in HPCD did not result in precipitation of the peptide. These studies document that HPCD enhances o-GH solubility in aqueous solutions. Preparations of GH in HPCD may eliminate solubility problems observed in current human GH preparations intended for parenteral use.
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PMID:Solubilization of ovine growth hormone with 2-hydroxypropyl-beta-cyclodextrin. 180 81


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