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C Laszlo

Publications and source records attributed to C Laszlo.

7 recordsLinked to original sources
PubMed1997

Motor unit number estimation: sample size considerations.

A computer model of the motor unit number estimation procedure was developed to evaluate the sampling error associated with estimates of the number of motor units in muscles. Two different distributions were used to model the motor unit amplitude distribution and were chosen in such a manner that they qualitatively matched the distributions observed under both normal and neurogenic conditions. As expected, the results indicated that estimation error decreases as a function of sample size. However, the relationship between these two variables was nonlinear in the sense that successive increases in sample size lead to progressively smaller decreases in estimation error. The results also indicated that the shape of the motor unit amplitude distribution plays an important role. Specifically, estimates obtained using the distribution modeling normal muscle were generally higher than the actual number of motor units in the muscle, which was not the case for the distribution modeling neurogenic muscle. In addition, the neurogenic distribution was associated with much smaller estimation error, suggesting that motor unit number estimation is well suited to the analysis of neurogenic disease processes.

Cell Count↗
PubMed1996

Motor unit estimates obtained using the new "MUESA" method.

Motor unit number estimates were obtained from the extensor digitorum brevis and thenar muscles using a new method called MUESA. MUESA is distinguished from other estimation methods in the manner in which it deals with probabilistic motor unit activation, which is more commonly referred to as "alternation." Because of "alternation," incremental increases in the observed muscle potentials often cannot be interpreted in terms of the successive activation of single motor units. In the MUESA method, the nerve is subjected to a number of constant-intensity stimulus trains, and the resultant muscle response sequences are decomposed into their constituent motor unit action potentials. In general, if a stimulus train results in the probabilistic activation of n motor units, we can expect to see up to 2n different potentials, with each potential representing a unique combination of active and/or inactive motor units. If all 2n potentials are indeed observed, the decomposition of the observed potential sequence into its constituent motor unit action potentials is very straightforward. For the majority of the cases in which the number of observed potentials is not an integer power of 2, we have developed a novel decomposition method based on the analysis of the relative firing rates of the motor units.

Adolescent↗
PubMed1995

Vibration and noise in pediatric emergency transport vehicles: a potential cause of morbidity?

BACKGROUND: Noise and vibration are stressors that may adversely affect the well-being of infants and children being transported between facilities. Although the problem has been recognized, little has been done to rectify the situation. HYPOTHESIS: That noise levels in transport incubators during use in transport vehicles exceed the recommended standards, and that vibration levels exceed those that are "very uncomfortable" for healthy adults. METHODS: We measured noise and vibration (n/v) levels inside and outside a neonatal transport incubator in seven transport vehicles (land, air, and water), and calculated maximum and average, weighted and unweighted levels. RESULTS: The maximum and average unweighted noise levels in all but one vehicle were over 99 dB. The incubator amplified noise at the lower frequencies (The Canadian Standards Association 1992 recommendation is that the noise level in transport incubators not exceed 60 dBA). The maximum vibration levels ranged from 0.86 m.S-2 to 2.35 m.S-2, and the average levels ranged from 0.33 m.S-2 to 1.46 m.S-2. (Vibration in excess of 1.5 is considered "very uncomfortable," and in excess of 2.0 is "extremely uncomfortable" for healthy adults.) CONCLUSIONS: Noise and vibration levels inside transport incubators in our most-commonly used transport vehicles often exceed the recommended limits. For neurologically immature and/or physiologically compromised infants and children, current levels of n/v in transport vehicles are too high, and could affect patient morbidity. These n/v levels require further study, and modification of equipment, primarily the incubators, is overdue.

Air Ambulances↗
PubMed1990

Detection of pYV+ Yersinia enterocolitica isolates by P1 slide agglutination.

Rabbit polyclonal antisera were raised against the pYV-encoded outer membrane protein P1 of five Yersinia enterocolitica strains belonging to serogroups O:3, O:5,27, O:8, and O:9. Analysis of these strains with the sera showed that P1 presented at least six different antigenic factors. Two of the serum specimens were chosen to test the P1 agglutinability of 797 strains isolated from various sources. This technique appeared to be more reliable than autoagglutination and Ca2+ dependency to monitor the presence of the pYV plasmid. Hence, we propose this P1-mediated agglutination as a new and easy virulence test.

Agglutination Tests↗
PubMed1990

Comparison of patient-controlled epidural analgesia and conventional intermittent "top-up" injections during labor.

In a prospective, randomized manner, bolus injection patient-controlled epidural analgesia (PCEA; n = 30) and conventional intermittent "top-up" injections (CIT; n = 28) of bupivacaine in nulliparous parturients during first stage of labor were compared. Group A (PCEA) patients self-administered, using a patient-controlled analgesia device, 4-mL increments of 0.125% bupivacaine with 1: 400,000 epinephrine, to a maximum 12 mL/h as required. Group B (CIT) patients received 12 mL of the same solution, on request, from the anesthesiologist. Hourly assessments of pain relief (visual analogue scale), satisfaction, sensory and motor block, blood pressure, and cervical dilatation were made. In addition, retrospective pain assessments were made in patients requesting analgesia in the preceding hour, indicating their maximum pain during that time. The groups were demographically comparable and equally low hourly bupivacaine requirements were seen (group A, 6.36 +/- 0.43 mg; group B, 6.23 +/- 0.39 mg) producing similar mean sensory levels. Pain relief obtained in both groups was similar but was associated with greater satisfaction in patients using PCEA (P less than 0.05). This study shows that PCEA is a viable alternative for providing pain relief in the first stage of labor.

Adult↗