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Biomedical subjects

L Philipson

Publications and source records attributed to L Philipson.

241 records · Page 14Linked to original sources
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Structure of three spliced mRNAs from region E3 of adenovirus type 2.

A cDNA library representing early adenovirus type 2 (Ad2) mRNA was constructed. The cDNA copies were inserted into the PstI cleavage site of the pBR322 plasmid, and clones containing sequences from region E3 of the Ad2 genome were identified by colony hybridization. Selected clones were characterized by restriction enzyme cleavage, hybridization, and partial DNA sequence analysis. The precise structure of three spliced mRNAs was established by comparing the results with the DNA sequence of region E3 from Ad2 (Herissé et al., Nucl. Acids Res. 8 (1980) 2173--2191; Herissé and Galibert, Nucl. Acids Res. 9 (1981) 1229--1249). One of the characterized mRNA species encodes the E3/19K glycoprotein, whereas the other two most likely encode the E3/14K protein. The results demonstrate, moreover, that certain splice points which are used to generate the major E3 mRNAs are also used to splice the supplementary leader segments to the fibre mRNA at late times after infection. Two separate poly(A)-addition sites were identified in region E3 by analysis of the cDNA clones; one is preceded by the hexanucleotide sequence AAUAAA, whereas the other is preceded by an altered hexanucleotide, having the sequence AUUAAA.

Adenoviruses, Human↗
PubMedDate not supplied

The effect of continuous lumbar epidural infusion of ropivacaine (0.1%, 0.2%, and 0.3%) and 0.25% bupivacaine on sensory and motor block in volunteers: a double-blind study.

BACKGROUND AND OBJECTIVES: In animal studies, ropivacaine has shown more pronounced sensory block than motor block, which makes it an interesting drug for postoperative pain relief. The aim of this study was to investigate the dose response of sensory and motor block during continuous epidural infusion of 0.1, 0.2, or 0.3% ropivacaine in volunteers in a double-blind manner. Bupivacaine 0.25% and isotonic saline were used as reference and control, respectively. METHODS: Each treatment group consisted of eight healthy men. After a bolus dose of 10 mL at the L2-L3 interspace, the solution in question was infused at 10 mL/h for 21 hours. Sensory block was evaluated by the pinprick, light touch, and Thermotest methods. Motor block was measured by the Bromage scale, by average rectified electromyography in abdominal muscles, and by mechanical measurement of isometric muscle force in the lower extremities. Mobilization of the subjects was attempted throughout the investigation. RESULTS: The number of blocked dermatomes (evaluated by pinprick) with 0.1% ropivacaine was significantly smaller than with the other test solutions (P = .002-.0008). Motor block was minimal with 0.1% ropivacaine, so that all subjects could be mobilized; it was moderate with 0.2 and 0.3% ropivacaine and most intense with 0.25% bupivacaine. The regression phase was significantly shorter with all three concentrations of ropivacaine than with bupivacaine (P < .01). CONCLUSIONS: Ropivacaine 0.1% produced limited analgesia and minimal motor block, so that ambulation was possible throughout the investigation. With 0.2 and 0.3% ropivacaine, analgesia was more extensive, and motor block was considered moderate. Ropivacaine 0.2% should be evaluated for future postoperative pain treatment.

Adult↗
PubMedDate not supplied

Evaluation of epidural sensory block by thermal stimulation, laser stimulation, and recording of somatosensory evoked potentials.

BACKGROUND AND OBJECTIVES: The existence of differential sensory block during epidural analgesia has been confirmed by some authors and disputed by others. This study attempts to elucidate this issue by using quantitative methods for evaluation of sensory block. METHODS: A single epidural injection of 20 mL 0.5% bupivacaine with epinephrine was administered at the L1-T12 level in 11 male volunteers. Sensory block was evaluated by two qualitative (pinprick and light touch) and two quantitative methods (thermal stimulation with Thermotest [Somedic, Stockholm, Sweden] and argon laser stimulation). For measurement of motor block in the lower extremities and in the rectus abdominis muscle, quantitative methods were used. Sensory block was also assessed by somatosensory evoked potentials recorded during electrical and laser stimulation at the most cranial analgesic dermatome (loss of sharpness in pinprick perception) and the anesthetic dermatome L2 (loss of light touch perception). RESULTS: The zone of anesthesia was smaller than the zone of any other investigated variable. The cranial spread of analgesia and motor block was lower than that of laser-assessed block. Partial block of laser perception and thermal perception lasted longer than analgesia and motor block. No consistent segmental or temporal differences were found between the Thermotest and laser methods. During epidural block, prolongation of latencies and reduction in amplitudes of somatosensory evoked potentials produced at the most cranial analgesic dermatome did not differ significantly from those produced at the anesthetic dermatome. CONCLUSIONS: No differential block of small nerve fibers was found during epidural analgesia by Thermotest and argon laser stimulation. Recording of somatosensory evoked potentials did not demonstrate significant difference between responses from the sites with most superficial and with most intense sensory block.

Adult↗
PubMedDate not supplied

Simulation of the influence of different factors on the motor nerve condition velocity measurement. Part 1: Normal conditions.

The result of a motor nerve conduction velocity measurement is dependent of a row of factors which will influence the measurement. These factors have been tested extensively in healthy volunteers. However, under pathological conditions it is not known to what degree the reported velocities are influenced by biological and technical factors. In an attempt to broaden our knowledge on the matter, a model was made to test different factors under varying conditions. Part I describes the model and reports results from calculations on simulated normal nerves. The results are in concert with results from healthy volunteers. Part II reports on results in pathological conducting nerves. The effect of the different factors affecting the nerve conduction velocities are shown. A simulation of doing a measurement twice and reporting the average showed a marked decrease of the variability in the reported nerve conduction velocity. This was more effective than eliminating any of the other factors influencing the measured conduction velocity.

Computer Simulation↗