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Biomedical subjects

C Dodds

Publications and source records attributed to C Dodds.

At least 19 recordsLinked to original sources
PubMed1999

General anaesthesia: practical recommendations and recent advances.

General anaesthesia has become, thanks to recently developed drugs, monitoring devices and delivery systems, a very well tolerated method of making the great surgical opportunities of the last few years available to all ages of patient. With a balanced and rational use of drug profiles, general anaesthesia allows even frail and very ill patients a margin of tolerability inconceivable just a few years ago. For the vast majority of patients, the risk from the general anaesthetic technique is so small it can be considered negligible. However, the majority of general anaesthetic drugs are both highly potent and very toxic, with many of the volatile agents still having a therapeutic ratio of about 4:1. The anaesthetic staff have to continually upgrade their skills and knowledge to ensure that harm does not result. It is, however, reasonable to offer some practical guidelines from the current literature on when to choose a general anaesthetic technique, either alone or with a regional local anaesthetic method, and when to avoid loss of consciousness. The complications expected from the use of general anaesthesia are reviewed, and the basis for these complications investigated. The currently available drugs and their place in anaesthetic practice are also assessed. Recent developments in the area of total intravenous anaesthesia and monitoring for potential awareness using bispectral analysis suggest that this technique should now be included in the choice of anaesthetic. Recommendations are made on both the selection of the technique, and the appropriate agents for a given group of patients.

Age Factors↗
PubMed1995

Can periodic breathing have advantages for oxygenation?

A model of the chemoreceptor mediated control of breathing is analysed. Hypoxia is simulated as low equilibrium arterial oxygen both at altitude and at sea level. Conditions for stable and unstable equilibria are examined. Transition to instability leads to periodic breathing and the model predicts that this can cause arterial oxygen to oscillate asymmetrically about the equilibrium in some cases, causing the average to rise. Periodic forcing functions have been applied to cerebral blood flow with the same effect on arterial oxygen. Such asymmetric oscillations leading to enhanced oxygenation have been observed in pulse oxymeter recordings from elderly postoperative patients. This may be important in interpreting studies of unstable breathing patterns and their possible relation to morbidity or mortality in infants (e.g. SIDS) and in the elderly (e.g. sleep apnoea, postoperative hypoxia). Periodic breathing could act as a protective adaptation to counteract pre-existing hypoxia.

Chemoreceptor Cells↗
PubMed1995

Anaesthetic drugs in the elderly.

The outcome of surgery in the elderly depends on the skill of the surgeon and the expertise of the anaesthetist caring for the patient. This anaesthetic proficiency depends initially on the application of the detailed knowledge of the drugs used during anaesthesia, and on the understanding of the way changes in the elderly patients' physiology with ageing affects both kinetic and dynamic facets of pharmacology. However, the very diversity of the elderly population makes their precise response to drugs unpredictable, and, therefore, clear, unequivocal guidance on practice is limited. The important changes in both physiology and pharmacokinetics with ageing are discussed before covering the specific drugs used in current anaesthetic practice in the United Kingdom. This review covers the drugs used primary for the induction and maintenance of anaesthesia, and only covers related fields where there are changes in recent practice that raise issues of importance during surgery. This review, therefore, deals mainly with the anaesthetic vapours and intravenous drugs, and with neuromuscular blocking agents. The restriction of space and the enormity of the subject demand that the areas covered in this review are solely limited to the major classes of drugs used routinely in general anaesthetic practice in the United Kingdom. The detailed pharmacokinetics and pharmacodynamics of drugs also used in the post-operative period, such as the wide variety of opiates, and of drugs mainly used in general medical practice, but occasionally used as premedicants or supplements during anaesthesia, have been monitored only in passing.

Age Factors↗
PubMed1995

Use of peptide combinatorial libraries in drug design: the identification of a potent serotonin reuptake inhibitor derived from a tripeptide cassette library.

BACKGROUND: Medicinal chemistry traditionally requires the identification of biologically active molecules by synthesizing and screening each purified substrate. Further progress in drug discovery then requires definition of the structure-activity relationship of the lead compound. More recently, combinatorial chemistry has emerged as a way to examine structure-activity relationships by screening a large mixture of compounds synthesized in a predictably random manner, without the labor-intensive costs of molecular isolation and purification. We set out to use this approach to examine the structural requirements for peptide binding to serotonin and dopamine transporters. RESULTS: We screened a tripeptide cassette library for serotonin and dopamine reuptake inhibition using cloned transporter assay systems. The method has afforded a number of tripeptide pharmacophores with inhibitory IC50 values ranging from 10 microM to < 1 microM in the dopamine and serotonin reuptake systems. The conformation of one of these tripeptides, N-acetyl-D-Trp-L-Phe-D-Lys-CONH2 (which inhibits serotonin uptake with an IC50 of 10 microM) was compared to that of the serotonin uptake inhibitor s-fluoxetine, and was shown to be more similar in conformation to fluoxetine than was an analogous tripeptide containing L-Lys (IC50 > 50 microM). CONCLUSIONS: We have identified five tripeptides with inhibitory IC50 values of < 10 microM in the serotonin reuptake system. One tripeptide was predicted to have pharmacophore features similar to that of fluoxetine, a selective and potent non-peptide serotonin reuptake inhibitor. Our results suggest that tripeptides derived from combinatorial libraries will help to define the important structural elements of pharmacophores.

Animals↗
PubMed1989

Myopic and nonmyopic aphakic retinal detachment: time interval and location of breaks.

Of 471 retinal detachments occurring in aphakic patients after undergoing intracapsular cataract extraction, we reviewed 318 eyes with uncomplicated aphakia (no vitreous loss). Myopic eyes had equatorial breaks 38% of the time versus 19% for nonmyopic eyes. The time interval between aphakia and detachment was shorter for myopic than for nonmyopic eyes. Our results showed a significant incidence of: (1) equatorial breaks in myopic eyes versus nonmyopic eyes (P less than 0.005), and (2) earlier detachments for myopic eyes versus nonmyopic eyes (P less than 0.005). The presence of equatorial breaks seemed to be associated with earlier retinal detachments.

Aphakia, Postcataract↗
PubMed1977

The interfering effect of distracting stimuli on the infant's memory.

Infants 3 1/2 months of age were assessed for the possible role of the dissimilarity of the distracting stimulus to the originally learned standard in a modified familiarization-distraction-test paradigm. When data for all subjects were analyzed, there was no evidence that the distraction had any interfering effect at all on the memory for the original standard. However, specialized analyses suggested that interference varied with the likelihood that subjects actually encoded the distracting stimuli might govern the probability or extent that an infant encodes the distracting stimulus rather than affecting the interference process directly.

Attention↗