Minimal mutation trees, and almost minimal trees, are constructed from two data sets, one of phenylalanine tRNA sequences, and the other of 5S RNA sequences, from a diverse range of organisms. The two sets of results are mutually consistent. Trees representing previous evolutionary hypotheses are compared using a total weighted mutational distance criterion. The importance of sequence data from relatively little-studed phylogenetic lines is stressed. A procedure is illustrated which circumvents the computational difficulty of evaluating the astronomically large number of possible trees, without resorting to suboptimal methods.

Bacteria↗

PubMed1982

Structure in tRNA data.

260 sequences of tRNA are compared, after their classification into six categories: prokaryotic (83 sequences) and eukaryotic (83 sequences) elongators, prokaryotic (10 sequences) and eukaryotic (11 sequences), initiators, lower eukaryotic mitochondrial tRNA (53 sequences) and archaebacterial tRNA (20 sequences). Beside the presence of invariable and semi-invariable positions in tRNA, non-random base distribution in almost all positions is also evident; most of them being characteristic of each class of tRNA. Therefore, during evolution it would seem that selectional pressures do act in so called variable positions as well as invariant positions of tRNA molecules. Results are discussed in relation to possible restrictions depending on functional and/or structural constraints of tRNA.

Animals↗

PubMed1971

Endocrine control of Na-K-ATP and seawater adaptation in Anguilla rostrata.

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Adaptation, Physiological↗

PubMedDate not supplied

Interpleural bupivacaine for postoperative analgesia following cholecystectomy: a randomized prospective study.

The effect of interpleural analgesia on postoperative hospital course was analyzed ina prospective randomized study of patients undergoing cholecystectomy. Control patients were treated in the standard manner with systemic narcotics alone; catheter patients had an interpleural catheter placed at the end of surgery and, in addition, could receive systemic narcotics if necessary. The catheter group received interpleural 0.5% bupivacaine with epinephrine every six hours for a total of four injections. Thirteen patients were in each group. Pain score, pulmonary function and narcotic requirement were measured over the first postoperative day. Catheter patients had a lower average pain score (visual analog scale (VAS), 3.6 versus 5.2), decreased narcotic requirement in the recovery room and improved oxygen saturation (96% versus 93%). However, there was no statistical difference in amount of morphine (catheter, 25 +/- 14 mg; control, 31 +/- 15 mg), number of narcotic injections (catheter, 3.8 +/- 1.5; control, 3.5 +/- 1.5), forced vital capacity (catheter, 44% preoperative control, 41% preoperative), recovery room time (catheter, 129 +/- 54 minutes, control, 117 +/- 39 minutes) or total hospital stay (catheter, 4.1 +/- 0.9 days; control, 3.7 +/- 0.8 days). Analysis of hourly VAS scores following a bolus indicated that the analgesia disappeared within approximately four hours. The mean time to a request for narcotic following a bolus was 4.2 hours (excluding 17 of a potential total of 52 instances when narcotic was not requested at all). Therefore, the duration of pain relief for subcostal incisions using interpleural 0.5% bupivacaine is approximately four hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗