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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The frequency response of isometric soleus muscle was determined efficiently by analysis of the unfused tension generated during short periods of random stimulation of the divided ventral roots, in anaesthetized cats.2. Despite the complexities of skeletal muscle, the frequency response of soleus, at moderate lengths and stimulation rates in the physiological range, is closely approximated by the frequency response function for a simple, linear, second-order system near critical damping.3. The soleus muscle shows a uniformly high sensitivity to fluctuations in nerve activity over a range of frequencies similar to the range of frequencies of muscular activity observable during behaviour. The nerve-muscle preparation appears to be well suited for smooth and steady motor activity, since it is much less responsive to the higher frequency components contained in individual action potentials or generated in tremor.4. The second-order parameters: low-frequency gain, natural frequency and damping ratio provide useful descriptions of the changes in the muscle's response caused by variations of muscle length, nerve stimulation rate or number of active motor units.5. A reduction in tension incurred, for example, during fatigue can be compensated to some extent either by a lengthening of the loaded muscle or through an increase in neural spike repetition rate. However, both mechanisms produce concomitant increases in the ;sluggishness' (increased damping and lower natural frequency) of the preparation. This sluggishness may arise out of limitations imposed by the mechanism for the re-uptake of calcium into the sarcotubular system.6. One naturally occurring method of increasing tension, by recruitment of more active motoneurones, seems to be desirable because tension can be augmented in this way without an increase in sluggishness. This is presumably because recruitment increases the muscle's response without affecting excitation-contraction coupling in fibres already active.
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PMID:Determination of the frequency response of isometric soleus muscle in the cat using random nerve stimulation. 435 9

A new technique employing continuous recirculating perfusion of the rat liver in situ, shaking of the liver in buffer in vitro, and filtration of the tissue through nylon mesh, results in the conversion of about 50% of the liver into intact, isolated parenchymal cells. The perfusion media consist of: (a) calcium-free Hanks' solution containing 0.05% collagenase and 0.10% hyaluronidase, and (b) magnesium and calcium-free Hanks' solution containing 2 mM ethylenediaminetetraacetate. Biochemical and morphologic studies indicate that the isolated cells are viable. They respire in a medium containing calcium ions, synthesize glucose from lactate, are impermeable to inulin, do not stain with trypan blue, and retain their structural integrity. Electron microscopy of biopsies taken during and after perfusion reveals that desmosomes are quickly cleaved. Hemidesmosome-containing areas of the cell membrane invaginate and appear to pinch off and migrate centrally. Tight and gap junctions, however, persist on the intact, isolated cells, retaining small segments of cytoplasm from formerly apposing parenchymal cells. Cells which do not retain tight and gap junctions display swelling of Golgi vacuoles and vacuoles in the peripheral cytoplasm. Cytoplasmic vacuolization in a small percentage of cells and potassium loss are the only indications of cell injury detected. By other parameters measured, the isolated cells are comparable to normal hepatic parenchymal cells in situ in appearance and function.
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PMID:High-yield preparation of isolated rat liver parenchymal cells: a biochemical and fine structural study. 490 Jun 11

Sheets of mucosal epithelial cells were released from guinea pig small intestine after incubation with ethylenediaminetetraacetate. Cells in sheets retained their columnar shape for 24 hr at room temperature, and exclusion of nigrosine suggested they had intact plasma membranes. When sheets were disaggregated individual cells had normal morphology for at least 4 hr. During isolation 16% of the total protein and 24% of the total lactic dehydrogenase were lost from the cells, but subsequent enzyme leakage was low. Leakage increased with shaking, incubation at 37 degrees C, or increasing the oxygen tension of the suspending medium, but was minimal when the Na(+):K(+) ratio in the medium was 8:1 and the osmolarity was high. Losses of particulate enzyme activities were negligible. Respiration was constant for up to 4 hr and was insensitive to calcium, bicarbonate, oxygen tension, and pH. It was inhibited by cyanide and iodoacetate and varied with the Na(+):K(+) ratio of the extracellular fluid and the structural integrity of the cells. All preparations concentrated potassium and excluded sodium, but lost this ability if ouabain was added or cells were broken. Potassium-42 uptake was also sensitive to temperature, ouabain, and structural integrity. The preparations are being used to study cell metabolism in the intestinal epithelium.
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PMID:Studies on epithelial cells isolated from guinea pig small intestine. 500 Jan 70

Nifedipine and verapamil injected into the cerebral ventricles of unanaesthetized cats produced a longlasting rise in the body temperature. The hyperthermic effect of nifedipine and verapamil were not dose-dependent. The hyperthermic effect of verapamil was preceded by a shortlasting fall in the body temperature, which was not dose-dependent. Calcium antagonists, nifedipine and verapamil also produced mydriasis, tachypnoea, dyspnoea, ataxia, tremor and muscular weakness. These symptoms were inconsistent and of slight intensity. In agreement with the theory of ionic set point controlling the body temperature, the most probable explanation is that calcium antagonists, nifedipine and verapamil produced changes in the body temperature by acting on sodium and calcium fluxes in the posterior hypothalamus.
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PMID:[Effects of nifedipine and verapamil on body temperature in cats]. 624 Oct 13

The authors report two computed tomographic observations of Fahr's disease without disturbances in calcium-phosphorus metabolism; the first case is a by chance discovery and the second one is characterized by a cerebellar tremor. From the literature data they discuss successively clinical, radiological and computed tomographic, neuropathological, aetiopathogenetic and therapeutic aspects actually presented by strio-pallido-dentate calcifications (SPD) or Fahr's disease.
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PMID:[Present data of Fahr's syndrome. Report of two cases of idiopathic strio-pallido-dentate calcifications revealed by computerized tomography (author's transl)]. 627 28

Single B-cells have been previously shown to respond poorly to glucose, in contrast to B-cells lodged in intact islets or in small groups of structurally coupled B-cells, isolated as such from islets. To analyze the role of cell coupling in glucose-induced insulin release, single B-cells were reaggregated in vitro and then tested for their secretory capability. Glucose as well as (Bu)2cAMP stimulated the degree of reaggregation during short shaking incubations (up to 180 min); onset of this process was most rapidly observed with (Bu)2cAMP (within 20 min), but after 180 min a comparable extent was measured with either 20 mM glucose or 0.5 mM (Bu)2cAMP. Calcium was an absolute prerequisite for reaggregation of B-cells. Glucose-induced insulin release from reaggregated B-cells was 4-fold higher than from single B-cells; this difference was not caused by some metabolic priming effect of glucose or (Bu)2cAMP, but appeared primarily mediated by the aggregated state of the cells. It is concluded that the secretory response of pancreatic B-cells is highly dependent on their aggregation with other B-cells. Both glucose and cAMP promote the adhesion of B-cells, and this may contribute to their well known insulinotropic effects.
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PMID:Effects of glucose and 3',5'-cyclic adenosine monophosphate upon reaggregation of single pancreatic B-cells. 632 39

Dementia, a syndrome of acquired intellectual deterioration, is an etiologically nonspecific condition that can be permanent or reversible. When evaluating demented patients, a careful exposure history will determine the possible role of drugs, metals, or toxins. Physical examination may reveal focal deficits in cases of intracranial mass lesions and spasticity or ataxia of the lower limbs if hydrocephalus is present. Coexistence of dementia and a peripheral neuropathy usually indicates the existence of a toxic or metabolic disorder. Depressed mood, sleep disturbance, anorexia, impotence, constipation, and psychomotor retardation indicate the presence of a depressive syndrome. Asterixis, myoclonus, and postural tremor are common in toxic-metabolic dementias, whereas resting tremor, choreoathetosis, or rigidity occur in progressive extrapyramidal disorder. EEG is focally abnormal in cases of cerebral mass lesions and shows generalized slowing in toxic-metabolic encephalopathies. CT will aid in the identification of hydrocephalus, subdural hematomas, and intracranial mass lesions. A thorough laboratory evaluation including complete blood count, erythrocyte sedimentation rate, electrolytes, blood urea nitrogen and blood sugar, liver and thyroid function tests, serum calcium and phosphorus levels, B12 and folate levels, serum copper and ceruloplasmin, VDRL, chest X-ray, electrocardiogram, and lumbar puncture may demonstrate treatable disorders that are adversely affecting intellectual function. Elderly individuals are particularly susceptible to the effects of toxic or metabolic disorders, and a mild dementia may be exaggerated by relatively minor fluctuations in metabolic status. Treatable causes of dementia should be sought in all demented patients.
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PMID:Treatable dementias. 635 58

Bepridil, a new calcium-channel blocking agent with an extended plasma elimination half-life of greater than 50 hours, was compared to placebo in 77 patients with confirmed coronary artery disease and chronic stable angina pectoris. The effects of bepridil were compared with those of placebo on angina frequency, nitroglycerin tablet use, the resting ECG and hemodynamics at rest and maximal exercise using a study design comprising 5 sequential 2-week single-blind treatment phases. After 2 weeks of placebo (phase 1), bepridil was given for 3 phases (2, 3 and 4) at total daily dosages of 200, 300 and 400 mg, respectively; the study was completed after a final reintroduction of placebo (phase 5). Within each phase once- and twice-daily regimens of bepridil were randomly compared. Bepridil (300 mg/day) reduced anginal frequency 68%, from 8.5 +/- 1.1 (standard error of the mean) to 2.7 +/- 0.7 attacks/week and nitroglycerin tablet use 76% (p less than 0.001). Bepridil improved exercise duration 26%, from 6.9 +/- 0.4 to 8.7 +/- 0.5 minutes (p less than 0.001) and exercise work 52%, from 2.7 +/- 0.3 to 4.1 +/- 0.4 kpm X 10(-3) (p less than 0.001) on a standardized treadmill protocol. Resting and peak exercise heart rate and blood pressure were unaffected by bepridil. The antianginal effects were similar with either once- or twice-daily treatment schedules. Minor side effects of nausea, epigastric discomfort and tremor were infrequent and there were no major side effects. The results of this large but preliminary, single-blind and short-term study suggest that bepridil is an effective and well tolerated antianginal agent when administered once daily.
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PMID:Bepridil for chronic stable angina pectoris: results of a prospective multicenter, placebo-controlled, dose-ranging study in 77 patients. 636 86

The tremorogenic effect of high pressure was antagonized in guinea pigs by intravenous treatment with taurine in doses of 250 and 500 mg/kg. Also pretreatment with 250 mg/kg taurine suppressed tremor development as evidenced by increased threshold and decreased amplitude. It is hypothesized that antagonism of pressure-induced tremor by taurine may be related to changes in membrane calcium transport.
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PMID:Antagonism by taurine of pressure-induced tremor in the guinea pig. 652 33

Diets differing in calcium (approximately 3.2 and .9%) and protein (15 and 12%) were fed to assess their effects on fertility, behavior, and physiological traits of White Leghorn males from lines selected for high (HA) and low (LA) antibody titers in response to the administration of sheep erythrocytes. Two trials, terminated when the males were 721 and 380 days of age, respectively, were conducted. In Trial 1, the HA males consumed significantly more feed than the LA males and those fed the low protein diets consumed more feed than those fed the high protein diets. No significant differences in feed intake were observed in Trial 2. Neither line, calcium level, nor protein level had a consistent effect on body weight in either trial. There were no significant first or second order interactions between main effects. Comparisons within ages and trials for percentage and duration of fertility revealed no significant differences between lines, protein level, or calcium level. Although the HA males produced significantly more antibodies to canine erythrocytes, dietary effects on antibody titers, heterophil: lymphocyte ratios, and plasma corticosterone were not significant. Thus, there was no indication that dietary treatments were inducing physiological adaptation. Behavioral adaptations, however, were observed; differences were significant for fear, territoriality, air pecking, and head shaking. It was concluded that behavioral responses symptomatic of nutrient deficiencies occur when no overt deficiency is present; this infers that an animal's well-being cannot be assessed strictly on the basis of behavioral consequences.
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PMID:Fertility and behavioral responses of roosters to diets differing in protein and calcium. 672 94


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