Muscle action potential precipitated complex repetitive discharge.
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Action Potentials↗
Biomedical subjects
L Gutmann
Publications and source records attributed to L Gutmann.
Ultrastructural pathology in emetine-induced myopathy.
Progressive myopathy developed in two women who consumed ipecac syrup containing emetine hydrochloride to induce vomiting as part of their anorexia nervosa. Muscle biopsy specimens were characterized by severe disruption of the sarcomeres. The ultrastructural spectrum extended from "Z-band streaming" to the formation of cytoplasmic bodies and also comprised abnormalities of the sarcotubular system, thus suggesting that muscle weakness may be related to both sarcomeric and sarcotubular lesions in this self-inflicted myopathy. It is tempting to suggest that muscle weakness may be correlated with or based on the pathology in sarcomeres and the sarcotubular system. As the myopathy is clinically reversible upon discontinuation of ipecac consumption the morphological findings should also be potentially reversible. Experimentally induced emetine myopathy may, thus, serve as a useful model to study morphological dynamics of sarcomeric lesions, which may be observed separately or simultaneously in a variety of spontaneously occurring human neuromuscular disorders.
Adult↗
Mechanisms of beta-lactam resistance in Haemophilus influenzae.
Haemophilus influenzae has become increasingly resistant to beta-lactam antibiotics. Three major mechanisms, both enzymatic and non-enzymatic, are involved. Enzymatic resistance is mainly due to production of a TEM-1 plasmid-mediated beta-lactamase, and in some cases to a new enzyme ROB-1. Of the non-enzymatic mechanisms, decreased permeability due to alteration of outer membrane proteins seems to be rare in comparison to decreased affinity of penicillin-binding proteins for beta-lactam antibiotics. Enzymatic resistance is present in about 10-20% of clinical isolates, while non-enzymatic resistance is present only in 2-4%.
Anti-Bacterial Agents↗
Interaction between piperacillin and pefloxacin or amikacin on the selection of resistant mutants of Pseudomonas aeruginosa.
Pseudomonas aeruginosa mutants were selected with piperacillin, pefloxacin, amikacin and the combinations pefloxacin-piperacillin and amikacin-piperacillin. With amikacin and the piperacillin-amikacin combination no mutants were selected. With piperacillin (1-32 x MIC) mutants resistant to carboxypenicillins, ureidopenicillins, monobactam and cephalosporins were selected. With pefloxacin, three different types of mutant were observed which showed different patterns of cross-resistance to pefloxacin, sulphonamides, imipenem, piperacillin and other beta-lactam antibiotics. With the pefloxacin-piperacillin association, mutants similar to one of the types selected by pefloxacin alone and resistant to both of the selective antibiotic were predominantly obtained. No mutants were selected with this combination if one of the antibiotics was used at a concentration equal to its MIC for the wild type strain and the other at concentrations above 4 x MIC. Since the association of piperacillin and pefloxacin was only moderately bactericidal against the predominantly cross-resistant mutant selected, the concentration of these antibiotics may have to be carefully controlled to prevent the emergence of such mutants.
Amikacin↗
Dissemination of the novel plasmid-mediated beta-lactamase CTX-1, which confers resistance to broad-spectrum cephalosporins, and its inhibition by beta-lactamase inhibitors.
The novel beta-lactamase CTX-1 (pI 6.3) encoded on a transferable 84-kilobase plasmid was found in six different bacterial species. It was responsible for a significant decrease in susceptibility towards most penicillins and cephalosporins, except imipenem, temocillin, and cephalosporins which have a 7-alpha-methoxy substituent. Synergy between either ampicillin, piperacillin, cefotaxime, ceftazidime, or aztreonam and three beta-lactamase inhibitors (clavulanic acid, sulbactam, and YTR 830) was generally found for different strains harboring CTX-1. This enzyme may be related to or derived from the TEM enzyme, since an intragenic probe of the TEM-1 gene hybridized with a fragment of the plasmid carrying CTX-1.
Cephalosporins↗
Mutation of Salmonella paratyphi A conferring cross-resistance to several groups of antibiotics by decreased permeability and loss of invasiveness.
A spontaneous one-step mutant of Salmonella paratyphi A selected on ampicillin showed cross-resistance to all beta-lactam antibiotics except imipenem and to aminoglycosides, chloramphenicol, tetracycline, trimethoprim, and quinolones. It also grew as small colonies. Examination of the cell envelope of the mutant showed a quantitative decrease in three major outer membrane proteins of 40.6, 39.6 (presumably porins), and 24 kilodaltons and quantitative as well as qualitative modifications in the ladder pattern of lipopolysaccharide. Direct evidence for decreased permeability in the mutant included reduced uptake of [3H]glucose and norfloxacin, reduced accessibility of aztreonam and benzylpenicillin to penicillin-binding proteins in whole cells, and decreased diffusion of lactose and cephaloridine into proteoliposomes that were reconstituted with outer membrane proteins from the mutant. There was also loss of invasiveness of the mutant into HeLa cells. We assume that a pleiotropic mutation was responsible for multiple alterations in the outer membrane components of the resistant mutant of S. paratyphi A.
Aminoglycosides↗
Case review and quantity of outpatient care.
Case review for patients belonging to a health maintenance organization was implemented in a hospital-based, multidisciplinary, outpatient clinic after the influx of 28,000 Medicaid enrollees. One-year follow-up of 138 patients with prepaid mental health insurance and 283 patients with fee-for-service mental health insurance revealed an annual mean of 6.1 treatment sessions; 78% completed treatment within eight sessions. The modal treatment was a single visit. Prepaid and fee-for-service patients did not differ in amount of care, although significant differences were found for insurance subgroups. These preliminary results suggest that case review has little effect on quantity of care.
Fees, Medical↗
Familial parkinsonism, apathy, weight loss, and central hypoventilation: successful long-term management.
We report a third family with six members with features of the syndrome of familial parkinsonism, depression, weight loss, and central hypoventilation. Patients with this syndrome typically die suddenly, presumably from central respiratory failure. Following multiple respiratory arrests, one affected member was successfully managed with aggressive pulmonary care, tracheostomy, and intermittent home mechanical ventilation, which, combined with carbidopa/levodopa, allowed for a functional lifestyle with improvement in apathy, mobility, and nutritional status.
Body Weight↗
Abduction-adduction hand tremor of myokymia.
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Fasciculation↗
Beta-lactamases in clinical isolates. Spectrum implications of sulbactam/ampicillin.
Combining ampicillin with an irreversible beta-lactamase inhibitor such as sulbactam is a promising technique for controlling infections due to resistant organisms. The combination not only restores the effectiveness of ampicillin against species that have acquired resistance to it, but it can extend the antimicrobial spectrum to species that have never exhibited susceptibility to ampicillin. However, the inhibition of beta-lactamases and the evaluation of inhibitors are still complicated by numerous factors known collectively as 'the epidemiology of beta-lactamases'. This refers to the distribution of enzymes in different bacterial species and in different geographical locations, the numerous types of enzymes, the variable number and amount of beta-lactamases that may exist in the same cell, and, of course, the potential for transfer of beta-lactamase resistance from one species to another.
Ampicillin↗
[The repetitive muscular action potential in neuromuscular transmission disorders due to acetylcholinesterase inhibition].
Neuromuscular transmission was studied in 11 patients with organophosphate intoxication. The compound muscle action potential (MAP) was recorded from the thumb after single, repetitive (1-50 Hz) and paired stimulation. All patients showed a prolonged MAP. The duration increased with the severity of intoxication. The number of peaks varied only slightly. In all cases repetitive stimulation reduced the later components of the MAP. There was no correlation with tetanic fade of the initial negative component. One patient had a pronounced tetanic fade but a slight reduction of repetitive components. In view of experimental studies a combined pre- and postsynaptic effect seems to be responsible.
Action Potentials↗
Myalgia.
Myalgia, a common symptom resulting from a variety of disease processes, often escapes a specific etiologic diagnosis. Despite the poorly understood pathogenetic mechanisms underlying myalgia, logical classification and clinical evaluation can lead to successful treatment in many cases.
Humans↗
Intraoperative somatosensory evoked potential monitoring in scoliosis.
During surgical correction of scoliosis, 63 patients had somatosensory evoked potential (SEP) monitoring of the spinal cord. Tibial nerves were unilaterally stimulated, and the potentials were recorded from the midcervical spine with surface and epidural needle electrodes. Over 85% had no significant change in their SEP and no postoperative neurologic deficits. Eleven percent had a significant change in their potential (amplitude decrease of greater than 60% and/or latency increase of greater than 2.5 msec) with no neurologic complications. One patient had a significant potential change and temporary postoperative sensory deficits did occur. One additional patient experienced postoperative neurologic complications but had no SEP change. This single false negative case, however, was clinically significant only for motor dysfunction, which is not monitored by the SEP. When changes in patient core temperature were compared to changes in SEP amplitude and latency, an intraoperative decrease in core temperature increased SEP latency and decreased amplitude, which may explain in part the false positive rate of the procedure.
Body Temperature↗
Origin of intramuscular nerve action potential.
The origin of the intramuscular nerve action potential (INAP) was investigated using conventional surface recording electrodes. The appearance of the INAP was (1) associated with subjective paresthesias, (2) recorded only when the reference electrode (G2) was over an appropriate digital nerve, (3) increased in latency as G2 was placed more distally, (4) blocked by an orthodromic sensory nerve action potential arising from the thumb, and (5) abolished with an anaesthetic block in the digital nerve proximal to G2. The findings indicate that the INAP is recorded by the G2 electrode from the digital nerve.
Action Potentials↗
Acute trimethyltin limbic-cerebellar syndrome.
An acute limbic-cerebellar syndrome was seen in six industrial workers who inhaled trimethyltin (TMT). Clinical features included hearing loss, disorientation, confabulation, amnesia, aggressiveness, hyperphagia, disturbed sexual behavior, complex partial and tonic-clonic seizures, nystagmus, ataxia, and mild sensory neuropathy. Severity paralleled maximal urinary organotin levels. One patient died and two remained seriously disabled.
Acute Disease↗
Timber rattlesnake venom-induced myokymia: evidence for peripheral nerve origin.
Facial and limb myokymia occurred in four consecutive cases of timber rattlesnake envenomation and represents the "fasciculations" frequently reported in this entity. The facial myokymia disappears within hours of antivenin therapy and the limb myokymia by increasing serum ionized calcium. These observations suggest that the action of the venom is a biochemical one, increasing peripheral nerve excitability.
Action Potentials↗
AIDS-related neuropathy.
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Acquired Immunodeficiency Syndrome↗