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Biomedical subjects

J A Rasmussen

Publications and source records attributed to J A Rasmussen.

8 recordsLinked to original sources

Residual curarization in the recovery room: atracurium versus gallamine.

Residual curarization in the recovery room was evaluated in 19 patients randomly allocated to two groups with nine and ten patients in each group, respectively. In one group atracurium was used for relaxation, and gallamine was used in the other. Anaesthesia was achieved with thiopental, diazepam, fentanyl and nitrous oxide in oxygen. Mean train-of-four (TOF) ratio in the gallamine and atracurium group was 0.63 and 0.91, respectively. Fifty per cent of the patients in the gallamine group had TOF ratios below 0.70, and none of these patients were able to sustain a head lift for 5 s. All patients in the atracurium group had TOF ratios above 0.70, and all of them were able to lift their head for 5 s. All patients were fully awake when they were evaluated, and no patient had any sign of respiratory difficulty. We conclude that residual curarization in the recovery room remains a problem and that this problem seems to be reduced when muscle relaxants of intermediate duration of action are used for relaxation during operation.

Adult↗

Significance of DNase I-hypersensitive sites in the long terminal repeats of a Moloney murine leukemia virus vector.

A Moloney murine leukemia virus-derived retroviral vector (N4) carrying the bacterial neomycin resistance gene (neo) was used to study the chromatin configuration of integrated proviral DNA in NIH 3T3-derived cell lines containing one copy of the vector DNA per cell. Three independently obtained cell lines were examined. In two of these cell lines, the vector was introduced by viral infection, while in the third the construct was introduced by DNA transfection. Such transfected cell lines (including the one examined) usually express 10- to 50-fold less virus-specific RNA than do cell lines obtained by viral infection. All three cell lines exhibited similar patterns of DNase I-hypersensitive (HS) sites. Two strong DNase I HS sites were detected in the 5' long terminal repeat, which contains signals required for proper and efficient initiation of viral transcription. One of these sites was found to overlap the viral enhancer sequences, while the other site mapped very close to the start site for viral transcription. A third HS site was detected in nearby internal viral sequences. Only one HS site was found in the 3' long terminal repeat, which contains the signal(s) required for proper addition of a poly(A) tail to viral transcripts. This HS site was located in the region of the viral enhancer. Several weak DNase I HS sites were also found in the cellular sequences adjacent to the integration sites, at different locations in each cell line analyzed. No common pattern of cellular DNase I HS sites was found. These observations suggest that the 5' and 3' long terminal repeats of integrated retroviral proviruses exhibit different chromatin conformations, possibly reflecting the different functions encoded by the otherwise identical sequences, and the DNase I HS sites detected in these studies reflect only a potential for transcription and are not a reflection of the high transcriptional activity characteristic of retroviruses.

Animals↗

SCE in lymphocytes of patients treated with single, large doses of diazepam.

When using the SCE test for evaluation of exposure in vivo to potential mutagens/carcinogens, it is necessary to consider possible confounding factors. In studies of possible mutagenic effects of pharmacological treatment the effect of concomitant administration of other agents such as sedatives may have to be considered. In order to assess whether diazepam per se influences SCE we have examined SCE in peripheral lymphocytes in 34 persons before and after oral administration of a single large dose of diazepam. 18 men and 16 women undergoing minor surgery of the hand received diazepam 0.2 mg kg-1 body weight orally on the day of operation, and venous blood samples were drawn on the day before the operation and again 2-5 h after the administration of diazepam. Both within cigarette smokers and non-smokers there was no statistically significant change of SCE following diazepam. It was concluded that there was no indication, from the SCE test, of an immediate mutagenic effect of a single large dose of diazepam and that such medication is not a confounding factor in studies by the SCE test.

Adolescent↗

Sound levels in emergency medical service.

Sound levels in an emergency medical service vehicle were measured during the summer of 1981. Excessive levels were found in the driver's compartment with the siren operating. Personnel measured showed low frequency hearing loss in the same range as the siren's operating frequencies.

Analysis of Variance↗