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)

The ionic requirements for electro-responsiveness in thalamic neurones were studied using in vitro slice preparations of the guinea-pig diencephalon. Analysis of the current-voltage relationship in these neurones revealed delayed and anomalous rectification. Substitution of Na+ with choline in the bath or addition of tetrodotoxin (TTX) abolished the fast spikes and the plateau potentials, described in the accompanying paper. Ca2+ conductance blockage with Co2+, Cd2+ or Mn2+, or replacement of Ca2+ by Mg2+ abolished the low-threshold spikes (l.t.s.). Substitution with Ba2+ did not significantly increase the duration of the l.t.s., suggesting that under normal conditions the falling phase of this response is brought about by inactivation of the Ca2+ conductance. The after-hyperpolarization (a.h.p.) following fast spikes was markedly reduced in amplitude and duration by bath application of Cd2+, Co2+ or Mn2+, indicating that a large component of this response is generated by a Ca2+-dependent K+ conductance (gK[Ca]). Following hyperpolarizing current pulses, the membrane potential showed a delayed return to base line. This delay is produced by a transient K+ conductance as it can be modified by changing the drive force for K+. Presumptive intra-dendritic recording demonstrated high-threshold Ca2+ spikes (h.t.s.s.) which activate a gK[Ca]. Such h.t.s.s. were also seen at the somatic level when K+ conductance was blocked with 4-aminopyridine. It is proposed that the intrinsic biophysical properties of thalamic neurones allow them to serve as relay systems and as single cell oscillators at two distinct frequencies, 9-10 and 5-6 Hz. These frequencies coincide with the alpha and theta rhythms of the e.e.g. and, in the latter case, with the frequency of Parkinson's tremor.
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PMID:Ionic basis for the electro-responsiveness and oscillatory properties of guinea-pig thalamic neurones in vitro. 673 93

Albuterol is a long-acting beta 2-adrenergic receptor-selective drug that relaxes airway smooth muscle. It is currently available in the United States in oral and metered-dose inhaler forms. Nebulizer solutions and parenteral preparations are likely to be marketed here in the future. The chemical modifications that make albuterol beta 2-selective also promote oral bioavailability and increased duration of action by decreasing sensitivity to degradative enzymes. Albuterol can also produce undesirable dose-related effects: metabolic effects including decreased levels of plasma potassium, phosphate, calcium and magnesium; increased levels of plasma glucose, insulin, renin, lactate and ketones; peripheral vasodilation and perhaps some direct cardiac stimulation resulting in decreased systemic and pulmonary vascular resistance, increased pulse pressure and tachycardia; and skeletal muscle tremor. These side effects are most common with parenteral administration and much less prominent with aerosol administration, which yields lower systemic concentrations. Limited pharmacokinetic data suggest a long distribution phase, a terminal half-life of 3-8 hours, and 10-20% oral bioavailability. Aerosolization of albuterol or a similar agent with a compressed-air nebulizer appears to be best first-line management of the patient with acute dyspneic asthma, but appropriate preparations for this kind of therapy are currently missing from the United States market. Intravenous albuterol has also been employed in acutely dyspneic patients, but produces more side effects than carefully administered intravenous theophylline, is impaired by lack of sufficient pharmacokinetic information to guide dosing, and is of uncertain efficacy in the asthmatic with respiratory failure. However, it appears to lack the potentially life-threatening side effects that can result when theophylline is used carelessly . In the ambulatory patient, aerosolized albuterol (or a similar agent) administered by metered-dose inhaler is an excellent agent for treatment as needed and/or for prevention of acute bronchospasm triggered by exercise or other predictable cause. Advantages include a high degree of efficacy, rapid onset and long duration of effect, and minimal side effects. Regularly scheduled administration of albuterol by metered-dose inhaler is a widely used and effective maintenance medication for patients requiring long-term prophylactic therapy. However comparisons of the ability of this regimen and the other common maintenance regimens (cromolyn and theophylline) to control chronic symptoms of asthma are needed.
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PMID:Albuterol: an adrenergic agent for use in the treatment of asthma pharmacology, pharmacokinetics and clinical use. 673 11

Responses of rumen microbes to fatty acids were evaluated by production of total volatile fatty acid and ratio of acetate to propionate. Fermentations were under carbon dioxide for 20 h in 50-ml Erlenmeyer flasks in a Dubnoff metabolic shaking incubator. Flasks contained 20 ml medium, 1 ml reducing solution, 750 mg substrate (450 mg hay plus 300 mg grain), and varying amounts of long-chain fatty acids supplied as free acids, as calcium salts, or as triglycerides. They were inoculated with 5 ml rumen fluid obtained from a cow fed 3.6 kg grass hay, 2.3 kg grain, and .2 kg tallow daily. Volatile fatty acid production was decreased by long-chain fatty acids that contained less than 18 carbon atoms and by unsaturated long-chain fatty acids with 18 carbon atoms. Lauric acid decreased volatile fatty acid production by 69% and induced unusual acetate/propionate ratio (40:1). Stearic acid, however, did not affect volatile fatty acid production or acetate/propionate ratio. Within two series of long chain fatty acids (myristic, palmitic, stearic, arachidic; stearic, oleic, linolenic), melting point accounted for 93 to 95% of the variation of volatile fatty acid production and acetate/propionate. As calcium salts, long chain fatty acids caused small changes of fermentation. Our data support the proposition that hard fats and calcium salts of long-chain fatty acids do not interfere with ruminal fermentation.
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PMID:Rumen fermentation in vitro as influenced by long chain fatty acids. 674 49

Culture-produced subendothelium (SE) has been prepared from cultured porcine aortic endothelial cells (ECs) by a rapid freeze-thaw, ice-shearing method. En face preparations of this in situ SE material are essentially free of intact or damaged cells and cell debris and consisted of an extensive meshwork of microfibrillar and amorphous material. Washed porcine platelets reacted extensively with this SE material and were associated with the SE as single adherent platelets, single spread platelets, and varying-sized platelet aggregates or 'microthrombi'. Platelet aggregates were associated only with the damaged or frayed edges of the SE, and the platelets had undergone extensive SE-induced contraction and degranulation, as indicated by transmission electron microscopy. Platelet-SE interaction was affected by pH, calcium, platelet concentration, rapid shaking and exposure time. Platelet-SE interaction was significantly enhanced by the addition of 0.1-1% citrated plasma or purified porcine F.VIIIR:WF. Pretreatment of the SE with thrombin, elastase, neuraminidase or hyaluronidase had no effect on platelet-SE interaction, whereas pretreatment with pepsin, plasmin, trypsin, alpha-chymotrypsin or collagenase decreased or completely abolished all platelet-SE interaction. Extraction of the SE with various solutions (high salt, detergents, etc.) had no effect on platelet-SE interaction, only solutions containing sodium dodecyl sulfate completely abolished all platelet-SE interaction.
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PMID:Culture-produced subendothelium. I. Platelet interaction and properties. 680 25

Production and characterization of Haemophilus pleuropneumoniae hemolysin were investigated by using 5 serotype 2 strains. The hemolysin was produced in chicken meat-infusion broth medium both in stationary and in shaking cultures. In stationary culture, hemolytic activity against horse RBC reached maximum at postincubation day 5 (at the late stage of stationary phase), and the activity was maintained at the same level for 2 days thereafter. The hemolytic activity of shaking culture reached a maximum at postincubation hour 9 (at the early stage of logarithmic-growth phase), gradually decreased, and disappeared at postincubation day 2. The hemolysin was shown to be an extracellular product of the bacterial cells. The RBC of horses, rabbits, and sheep were highly susceptible to the hemolysin, and those of pigs and guinea pigs were less susceptible, whereas RBC of 60-day-old chicks were not susceptible. The hemolysin was not inactivated by autoclaving at 121 C for 2 hours, and by treatments with formalin, trypsin, or pronase. The presence of calcium or magnesium ions did not change the activity, whereas iodoacetic acid significantly reduced the activity.
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PMID:Characterization of the hemolysin produced by haemophilus pleuropneumoniae. 683 24

The effect of calcium chloride injected into the cerebral ventricles of group-housed unanaesthetized cats upon vocalization (rage, hissing and snarling), fighting (attack with paws and claws, defense with paws and claws and biting), mydriasis, tremor and clonic-tonic convulsions produced by carbachol and eserine injected similarly was investigated. Calcium chloride depressed or almost completely abolished the vocalization and fighting due to carbachol and eserine. On the other hand, mydriasis, tremor and clonic-tonic convulsions evoked by carbachol and eserine were not significantly changed by calcium chloride. It is apparent that calcium chloride can "dissociate" vocalization and fighting from autonomic and motor phenomena such as mydriasis, tremor and clonic-tonic convulsions caused by carbachol and eserine. Calcium chloride inhibited the vocalization and fighting produced by carbachol and eserine most probably by a nonspecific stabilizing action on central muscarinic cholinoceptive sites. These results further support the view that calcium ions in excess have an atropine-like action also in the central nervous system.
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PMID:Effect of calcium chloride on gross behavioural changes produced by carbachol and eserine in cats. 689 85

This study was undertaken to determine the in vitro enamel fluoride uptake and distribution from fluoride-containing orthodontic cements after 21 days' exposure and the effect on acid demineralization. Three successive acid-etch biopsy specimens were taken from tne facial middle third of thirty maxillary central incisors. Orthodontic bands were cemented to these teeth, ten each with (A) zinc phosphate, (B) zinc phosphate containing 5 percent SnF2, and (C) silicophosphate cement, respectively. The teeth were suspended individually in synthetic saliva at 37 degrees C. in a shaking incubator for 21 days. The bands were removed, the cement was cleaned off, and three successive biopsies were carried out electrometrically and for calcium by atomic absorption spectroscopy. Fluoride concentrations were adjusted to depths of 10.0, 20.0, and 30.0 micron for the three biopsies, respectively. The acquired fluoride was calculated and the data were analyzed statistically. In addition, six teeth each with bands cemented with cements A, B, and C, respectively, were incubated in synthetic saliva for 21 days, after which the bands were loosened and the teeth were suspended for a further 3 months in a caries-producing medium. After careful cleaning, the enamel surfaces were examined by microradiography and scanning electron microscopy for demineralization. Results showed that acquired fluoride at the first depth was highest with cement C, followed by cement B, with cement A producing a net loss of fluoride. Further, the greater the fluoride uptake, the more resistant the enamel was to demineralization.
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PMID:Enamel fluoride uptake from orthodontic cements and its effect on demineralization. 694 Apr 47

N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) and its derivatives are putative calmodulin antagonists that bind to calmodulin and inhibit Ca2+/calmodulin-regulated enzyme activities. Autoradiographic studies using tritiated W-7 showed that this compound penetrates the cell membrane, is distributed mainly in the cytoplasm, and inhibits proliferation of Chinese hamster ovary K1 (CHO-K1) cells. Cytoplasmic [3H]W-7 was excluded completely within 6 hr after removal of [3H]W-7 from the culture medium. N-(6-aminohexyl)-1-naphthalenesulfonamide, an analogue of W-7 that interacts only weakly with calmodulin, proved to be a much weaker inhibitor of cell proliferation. CHO-K1 cells were synchronized by shaking during mitosis and then released into the cell cycle in the presence of 25 microM W-7 or 2.5 mM thymidine for 12 hr. Cell division was observed approximately 6 hr later. The results suggest that the effect of W-7 on cell proliferation might be through selective inhibition of the G1/S boundary phase, which is similar to the effect of excess thymidine. This pharmacological demonstration that cytoplasmic calmodulin is involved in cell proliferation is significant; W-7 and its derivatives may be useful tools for research on calmodulin and cell biology-related studies.
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PMID:N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, a calmodulin antagonist, inhibits cell proliferation. 694 88

Symmetrical calcification of the basal ganglia was found in 2% of 8000 computerized tomography (CT) scans. Of 19 cases, only 2 were detectable on conventional skull films. The less prominent calcifications were most often found in the region of the pallidum, the knee of the internal capsule. Also, the lesions were generally symmetrical. Thus these factors must be considered basic morphological characteristics of the pathophysiological process. Additional neurological disorders were present in 6 patients. Neurological symptoms in the remaining 13, when present, depended on the extent of the lesion. The most common finding was tremor, although disturbances of fine motor control, transient lateralizing signs, and seizures were also noted. No particular constellation of symptoms or signs permitted accurate clinical localization of the lesions. The patients could be divided into three groups on the basis of clinical findings: (1) young people with marked cerebral calcinosis ('idiopathic' calcification of basal ganglia), (2) patients with hypoparathyroidism, and (3) older patients with relatively little calcification. Most patients with calcific lesions will be included in the third group. Any calcification of basal ganglia detected by CT scans demands careful evaluation of calcium metabolism.
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PMID:[Clinical, endocrinological, and computerized tomography scans for symmetrical calcification of the basal ganglia (author's transl)]. 738 49

Reactions to human serum albumin (HSA) in therapeutic plasma exchange (TPE) are rare. Nevertheless, older literature describes possible adverse effects, including specific immune responses to albumin or other proteins, and reactions due to contaminating organisms or pyrogen. During an eight day period three patients in our unit had unusual reactions after infusion of 1.5-2 L of HSA. Patient 1 had trembling that persisted for 20 min. Patient 2 had shaking for 40 min despite calcium gluconate infusion, and fever to 100.8 degrees F. Patient 3 had severe rigors that subsided after 90 min when meperidine was finally given, and fever to 103.5 degrees F. Record reviews revealed that all three patients had received HSA from the same lot, and that only one other TPE patient had received HSA from that lot. Neither our pharmacy nor the manufacturer was aware of other reactions associated with that lot. Material from a bottle only partially infused to patient 3 was negative in culture and was negative for pyrogen when retested by the manufacturer. Nevertheless, because patients 1 and 2 had each had multiple previous uneventful TPEs and because all three patients tolerated subsequent TPEs without incident when another brand of HSA was used, we conclude that these patients had pyrogen reactions to the implicated HSA lot. This experience illustrates the value of cluster recognition in arousing suspicion of unusual reactions to HSA and the value of recorded lot numbers in pursuing such suspicions. Apheresis personnel should be aware of the potential for pyrogen reactions with HSA and should record lot numbers of all fluids infused during TPE.
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PMID:Pyrogen reactions to human serum albumin during plasma exchange. 759 21


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