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Biomedical subjects

J C Clarke

Publications and source records attributed to J C Clarke.

30 records · Page 2Linked to original sources
PubMed1990

The conditioning of aversions to familiar and preferred flavours: a new aversion therapy model.

The present study examined the ability of rats to develop aversions to familiar flavours and to flavours that they had previously acquired a preference for. Rats were first conditioned to prefer a CS+ flavour over a CS- flavour by pairing CS+ intake with the consumption of a starch solution (16% Polycose). A second group was exposed to the same training but preference conditioning was prevented by inhibiting starch digestion with the drug acarbose. The rats were next given aversion training; the CS+ flavour was now paired with toxicosis (LiCl injection) while the CS- flavour paired with a control treatment (NaCl injection). The results of two-choice tests revealed that aversion training produced significant avoidance of the CS+ flavours in both the group that had acquired a preference for this flavour as well as in the no-preference group. The value of using conditioned flavour preferences as targets for aversions to model the aversion therapy approach to alcoholism is discussed.

Journal Article↗
PubMed1990

The role of emergency venography in the diagnosis and management of deep venous thrombosis.

A retrospective study of patients who had undergone venography for suspected deep venous thrombosis during a six month period was undertaken to assess the influence of the examination on the subsequent management. Of these patients 38.6% had evidence of thrombus confirmed by the examination. This figure is comparable with other published results and did not bear out the impression that too many negative venograms were being obtained. Objective diagnosis of deep venous thrombosis is essential to ensure safe and cost-effective management. Other techniques have been advocated for the diagnosis of this condition but all have significant disadvantages compared with venography.

Adolescent↗
PubMed1978

Control of polydipsic drinking by a taste aversion procedure.

Rats were given daily sessions with free access to food and saccharin flavored water. After fluid consumption had stabilized food was delivered once every minute. Water was always available in the home cage. All rats showed the marked increase in fluid consumption known as schedule-induced polydipsia. The rats were then poisoned with lithium chloride after each of three sessions in an attempt to condition a taste aversion to the saccharin. On recovery from the toxicosis all rats showed first a reduction and then a recovery in saccharin intake. To establish the nature of this effect, the rats were poisoned after saccharin consumption in the home cage. Again there was a marked reduction in polydipsic drinking in the experimental chamber. These results indicate that common incentive mechanisms govern normal and polydipsic drinking and stand in contrast to published results pointing to different drive systems in the brain mediating normal and polydipsic drinking.

Animals↗
PubMedDate not supplied

The "medicinal effect": a possible mechanism in the development of severe alcohol dependence.

An examination of the change in attractiveness of a flavor subsequent to pairing with recuperation from malaise was undertaken. Forty-five subjects consumed a flavor after the rotation-induced motion sickness at two different intervals. Twenty-four consumed, on three separate conditioning trials, the paired flavor immediately as malaise began to decline (short-delay group), the remainder, when malaise had completely diminished (long-delay group). All subjects also consumed an unpaired flavor the morning after each session. Analysis of variance revealed that the paired flavor was rated as more highly attractive than the unpaired flavor, and this effect was only present in the short delay group. These results were taken as supporting the existence of conditioned flavor preferences in humans and interpreted as a possible learning mechanism in the development of severe alcohol dependence.

Adult↗
PubMedDate not supplied

Can wear in total hip arthroplasties be assessed from radiographs?

The validity of wear measurements from total-hip radiographs was assessed using a wear simulator which consisted of a total hip prosthesis mounted on a Plexiglas orientation jig. Wear was mesured by a micrometer device and uni- and duoradiographic methods of wear measurement were used with a variety of acetabular cup orientations. In the initial calibration studies the duoradiographic technique proved to be more accurate. The source of the inaccuracies of the uniradiographic method was determined analytically by means of a geometrical model. Forty-inch or 72'' source-to-object film-distances provided similar accuracy and the errors in wear measurement varied from --0.1 +/- 0.4 mm (2 S.D.) to 0 +/- 0.9 mm for wear magnitudes of 1 and 5 mm respectively, regardless of cup position. In subsequent calibration studies the previous radiographs were compiled to represent seven hypothetical patients at various stages of follow-up whose prostheses exhibited between 1 and 5 mm wear. Clinicians assessed the degree of wear, using both the uni- and duoradiographic techniques, under supervision but unaware of the true position and orientation of the wear track. The resulting errors were of the same order as the wear magnitudes being measured. The location of the measurements on the radiographs was then restricted to approximately the true wear axis but again the errors were so large that it was still impossible to make any valid wear assessments. The calibration runs were therefore terminated at this point and it was concluded that wear measurements could not be made from clinical radiographs.

Arthroplasty↗