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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the possibility of interactions between buccal cutaneous sensory receptors and voluntary maximum isometric contractions of the masseter muscles, six adult subjects exercised maximum teeth clenching before and after spraying the right cheek surface with aerosol containing 20% benzocaine. The right cheek and masseter muscle served as the experimental side, the left cheek and masseter muscle as the control side. Isometric motor outputs, on the right and left sides, were monitored by integrated surface electromyography over periods of 10 seconds. Topical surface anesthesia provided no evidence of motor modulation by cutaneous tactile receptors. Before and after anesthesia, the two muscles showed nearly identical and well-coordinated motor innervation patterns. It is suggested that the cortical motor commands of maximum isometric contractions, with recruitment of practically all available motor units, overrule all modulatory inputs except those of fatigue.
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PMID:Effect of topical cheek surface anesthesia on isometric contractions of the human masseter muscle. 342 35

Chronopharmacology involves the investigation of drug effects as a function of biological time and the investigation of drug effects on rhythm characteristics. Three new concepts must be considered: (a) the chronokinetics of a drug, embracing rhythmic (circadian) changes in drug bioavailability (or pharmacokinetics) and its excretion (urinary among others); (b) the chronaesthesia of a biosystem to a drug, i.e. circadian changes in the susceptibility of any biosystem to a drug (including organ systems, parasites, etc.); skin and bronchial chronaesthesia to various agents have been documented in man; and (c) the chronergy of a drug, taking into consideration its chronokinetics and the chronaesthesia of the involved organismic biosystems. The term chronergy includes rhythmic changes in the overall effects and in the effectiveness of some drugs. Clinical chronopharmacology is useful for solving problems of drug optimization, i.e. enhancing the desired efficiency of a drug and reducing its undesired effects. Circadian rhythms can be demonstrated in various effects of drugs on sleep, anaesthesia and related processes. For example, in the rat the duration of sleep induced by substances such as pentobarbital, hexobarbital, Althesin (alphaxadone and alphadoline in castor oil) is circadian system stage-dependent. Time-dependent changes of liver enzymes (e.g. hexobarbital oxidase) play a role in these circadian rhythms. The clinical chronopharmacokinetics of benzodiazepines have been documented in man. Chronopharmacologic methods can be used to study desired and undesired hypnotic effects of substances. Such is the case of new antihistamines (anti-H1), which do not induce sleepiness, in either acute or chronic administration. Pertinent also is the problem of intolerance to shift-work. Intolerant shift-workers are subject to internal desynchronization between at least two rhythms (e.g. activity-rest cycle and body temperature). Clinically these workers suffer from sleep disturbances, persistent fatigue and are regular users of sleeping pills, which is also a symptom of intolerance. However, over the long-term, these drugs are of no help to intolerant shift-workers.
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PMID:Circadian rhythms in effects of hypnotics and sleep inducers. 351 93

7,500 deliveries occurred from the date of opening of the Maternity Hospital Jean-Rostand. 3,500 of these were conducted under epidural anaesthesia. At different stages prospective studies were carried out to recall the effect of adding fentanyl to bupivacaine when the epidural injection was made. A pharmacokinetic study. This shows that the levels in the mother and the fetus begin to coincide more with the number of doses that are given and pass from 0.3 after 50 micrograms have been administered to 0.5 after 100 micrograms have been administered and 0.7 after 150 micrograms have been administered. The fetal levels are far lower than those required to depress respiration. The half life of distribution through the circulation has been worked out at 4 minutes and the half for elimination of the drug at 460 minutes. The maternal levels show great fluctuations and late alterations. Analgesia is earlier, more complete and more prolonged when fentanyl is added. Fentanyl also masks irregularities. Undesirable effects such as tiredness, pruritus, nausea, vomiting and urinary retention occur infrequently and last only for short periods of time. No mother had respiratory depression. The doses of bupivacaine that had to be given were as a whole less when fentanyl was added. In 40% of cases it only required one injection to achieve analgesia throughout the whole labour. The length of labour and the number of caesarean operations carried out did not change.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Fentanyl in peridural obstetrical analgesia. Evaluation after 4 years' use]. 358 62

The diaphragm, a ventilatory muscle, has abundant sensory innervation. The effects of phrenic afferent activation on ventilation have been varied. In this study the proximal end of the phrenic nerve was electrically stimulated, and the effects on ventilation were measured in supine dogs anesthetized with either alpha-chloralose or pentobarbital sodium. We found a maximum increase in ventilation of 45 +/- 4% in the alpha-chloralose group and an increase in mean arterial blood pressure of 18 +/- 4%. This response was obtained at high stimulus intensities (60 times twitch threshold). Stimulation of the proximal end of the gastrocnemius nerve produced a similar ventilatory response (61 +/- 10%) but at lower stimulus intensities. During pentobarbital sodium anesthesia both the hyperventilation and the pressor response were produced; however, ventilation was increased by an increase in respiratory frequency. The reflex was abolished by sectioning of the cervical dorsal roots (C4-C7). Proximal cold blockade of the nerve abolished the response at a perineural temperature of 1.35 +/- 0.64 degrees C. The main effect of activation of phrenic afferents was an increase in ventilation and blood pressure that was mediated by unmyelinated fibers and possibly thin myelinated fibers. This response is similar to skeletal muscle afferent activation and may play a role in ventilatory drive during such conditions as exercise and respiratory muscle fatigue.
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PMID:Ventilatory effects of stimulation of phrenic afferents. 365 54

1. Long-term electrical stimulation was given to the peroneal nerve of deafferented hindlimbs in hemispinalized adult cats. The amount of stimulation covered 0.5-5.5% of total time per day, different in different animals. For some aspects of the present study, use was also made of cats subjected to "tonic" patterns of chronic stimulation (typically covering 50% of total time; 10, 16). 2. In a terminal acute experiment under general anesthesia, performed after 4 or 8 wk of long-term stimulation, one of the treated peroneal muscles (m. peroneus longus, PerL) was used for measurements of the resistance to contractile fatigue. The fatigue test consisted of 0.33-s bursts of motor-nerve stimulation at 40 Hz, repeated once a second for 4 min (6, 7). During this fatigue test, the evoked compound spikes of the muscle were recorded by electromyographic (EMG) techniques. Following the physiological procedures, PerL was removed for further histochemical analysis. In transverse sections, measurements of optical density were made in central regions of single fibers after staining for the activity of an oxidative enzyme, succinate dehydrogenase (core SDH). 3. Findings from chronically stimulated PerL muscles were compared with three kinds of control PerL muscles: 1) those contralateral to the stimulated ones, 2) those from the operated side of animals that had been deafferented and hemispinalized but not subjected to chronic stimulation, and 3) those from untreated normal animals. 4. Stimulation patterns covering both greater than or equal to 50% and 5-5.5% of daily time gave a marked improvement of fatigue resistance. Pulse rate seemed of little importance for these effects. The pattern covering only 0.5% of total daily time caused no increase of contractile endurance beyond that of normal muscles. 5. During the fatigue test of a control muscle (see above), the amplitude of the compound EMG spikes typically showed a marked decline. This "EMG depression" was effectively counteracted by all the present patterns of chronic stimulation, including the 0.5% pattern. 6. Fibers of chronically stimulated muscles became more similar to each other with respect to their density of core SDH staining. However, among muscles treated during 0.5-5.5% of total daily time, the degree and pattern of change in core SDH staining was not related to the amount and pattern of chronic stimulation or to the resulting degree of contractile endurance.
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PMID:Effects of physiological amounts of high- and low-rate chronic stimulation on fast-twitch muscle of the cat hindlimb. II. Endurance-related properties. 365 85

The use of the Shaw hemostatic scalpel eliminates the frustration and physical fatigue formerly associated with the carving of solid silicone implants from blocks of silicone of all grades. It enables very accurate shaping and saves operating and anesthesia time. The smooth end product may, in many cases, eliminate the need for factory-made implants. This method of shaping silicone block is highly recommended. It is not suggested that the instrument should be purchased for this purpose alone, but if purchase of the scalpel is being considered for other purposes, this may be a significant factor in the decision.
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PMID:Contouring of a solid silicone block: a new use for the Shaw scalpel. 376 33

Subjective feeling of fatigue was assessed before and 10, 20 and 30 days after uncomplicated abdominal surgery in 52 patients and after minor otological surgery in 15 patients. In major surgery fatigue increased from 3.0 +/- 0.2 (mean +/- s.e.m.) arbitrary units pre-operatively to 6.1 +/- 0.3, 5.3 +/- 0.3 and 4.1 +/- 0.3 on day 10, 20 and 30, respectively (P less than 0.001). In contrast, after minor surgery fatigue did not change from before surgery (2.1 +/- 0.3) to day 7 (2.9 +/- 0.5) (P greater than 0.05), day 20 (2.3 +/- 0.4) (P greater than 0.4), or day 30 after surgery (2.1 +/- 0.3) (P greater than 0.9). Differences in fatigue between groups were significant postoperatively (P less than 0.001), but not preoperatively (P greater than 0.05). Mean duration of surgery was similar in the two groups. In the abdominal group an increase in postoperative fatigue did not correlate with age, sex, pre-operative degree of fatigue, actual body weight, triceps skinfold thickness (TSF), arm muscle circumference (AMC), anthropometric index (body weight X TSF X AMC) or serum-transferrin, but did slightly with pre-operative body weight related to ideal body weight (r = -0.3, P less than 0.05). Thus, the magnitude of the trauma and not the duration of anaesthesia may be important for occurrence of postoperative fatigue. Furthermore, fatigue after elective abdominal surgery seems to be unpredictable from the pre-operative status of the patient.
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PMID:Influence of pre- and intra- operative factors on the occurrence of postoperative fatigue. 396 34

A method for determining muscle strength in the lower extremities was developed and its clinical application evaluated in ten elderly, healthy subjects, and also subsequently in one of them during spinal anaesthesia. With the subject lying in the lithotomy position on a modified operating table, muscle strength measurements were made during flexion of the hip, extension of the knee and plantar flexion of the big toe. The electromechanical performance of the apparatus was stable, and the maximum measurement errors observed at loads of 245 and 49 N were 4 and 11% of the deflections, respectively. The subjects underwent repeated muscle strength measurements during a 4-h period without any difficulty. No signs of muscular fatigue were observed. The variation of the measured isometric muscle strength was small and the average coefficient of variation roughly 10%. In the patient receiving spinal anaesthesia, the degree of motor block was determined, and the results are presented graphically. This new method for evaluation of motor block in the lower extremities is a reliable quantitative method for bilateral, three-joint muscle strength measurements, which is also applicable during regional anaesthesia.
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PMID:A new method for measuring motor block in the lower extremities. 397 24

A hundred patients scheduled for elective abdominal surgery were randomized to either general anaesthesia (low-dose fentanyl) and systemic morphine for postoperative pain or combined general anaesthesia and epidural analgesia with etidocaine 1.5% intraoperatively (T4-S5) and bupivacaine 0.5% 5 ml/4 h for 24 h and morphine 4 mg/12 h for 72 h. Postoperative pain was better controlled by the epidural regimen (P less than 0.0001). We found no significant reduction in postoperative mortality (6% to 2%), pneumonia (28% to 20%), cardiac dysrhythmia (10% to 5%) and wound complications (14% to 11%) by the epidural analgesic regimen. The incidence of deep venous thrombosis (125I-fibrinogen scan) was 32% after general anaesthesia and low-dose heparin and 34% after epidural analgesia with no prophylactic antithrombotic treatment (P greater than 0.9). Postoperative weight loss and decrease in serum-albumin and serum-transferrin, as well as the reduction in haemoglobin and the need for postoperative transfusions, were similar in the two groups. Convalescence, as assessed by postoperative fatigue, restoration of bowel function (flatus, bowel movement and food intake) and the time until the patients were self-aided at their preoperative level, was not reduced by epidural analgesia. Since 50% of the patients in each group suffered from one or more of the above-mentioned postoperative complications, this epidural regimen was not effective in reducing postoperative morbidity after major abdominal surgery despite the achievement of adequate pain relief.
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PMID:A controlled study on the effect of epidural analgesia with local anaesthetics and morphine on morbidity after abdominal surgery. 408 79

The injuries to the lower extremities seen in a surgical office may be classified as contusions, lacerations, sprains, lesions of tendons and their sheaths, involvement of bursae, chronic muscle fatigue, infections and deformities of the nails, leg ulcers, and fractures of the ankle, foot and toes. The treatment of these conditions in an office will vary under different circumstances, but one should be guided by certain fundamental rules. Contusions are best treated by the application of elastic compression bandages. Extensive lacerations should be explored under local anesthesia with the tourniquet in place, injured tissue excised, and the wound sutured. Ankle sprains should be strapped. Immediate hospitalization must be considered in all moderate to severe initial sprains to the knee. Lesions of bursae usually respond to the injection of hydrocortisone preparations. The same treatment is used in chronic muscle fatigue, plus immobilization of the part. Chronic recurrent infection and deformities of the nails are treated by removal of the nail under local anesthesia. Fractures of the ankle, the foot and toes may be reduced under local anesthesia and a cast applied. If further swelling is feared, the patient should be put in hospital immediately.
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PMID:Office treatment of lower extremity injuries. A view of feasibility, limitations and hazards. 590 45


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