Biomedical subjects

R Featherstone

Publications and source records attributed to R Featherstone.

4 recordsLinked to original sources

PubMed2000

Involvement of the medial septum in stress-induced relapse to heroin seeking in rats.

Intermittent footshock stress has been shown to reinstate extinguished drug-taking behaviour in rats, but the brain areas involved in this effect are to a large degree unknown. Here we studied the role of the septum in stress-induced reinstatement of heroin seeking. Rats were trained to self-administer heroin for 9-10 days (three 3-h sessions per day, 0.1 mg/kg per infusion). Following training, extinction sessions were given for 8-13 days by substituting saline for heroin, and then tests for reinstatement of heroin seeking were carried out. Reversible inactivation of the medial septum with tetrodotoxin (TTX; 1-5 ng, infused 25-40 min before the test sessions) reliably reinstated heroin seeking, mimicking the effect of 15 min of intermittent footshock. This effect of TTX was not observed after infusions made 1.5 mm dorsally into the lateral septum. In other experiments, it was found that infusions of a low, subthreshold dose of TTX (0.5 ng) into the medial septum, when combined with 2 min of footshock that in itself was ineffective, reinstated heroin seeking. Furthermore, electrical stimulation (400 microA pulses, 100 micros duration, 100 Hz frequency) of the medial septum during exposure to 10 min of intermittent footshock attenuated footshock-induced reinstatement of heroin seeking. These data suggest a role for the medial septum in stress-induced relapse to drug seeking. The septum is thought to be involved in neuronal processes underlying behavioural inhibition, thus we speculate that stressors provoke relapse by interfering with these processes.

Animals↗

PubMed1996

Laparoscopic training in residency program.

The use of laparoscopy in general surgery has provided surgeons with a new approach to multiple procedures. New techniques are being developed daily. Laparoscopic training for surgical residents must be incorporated into their curriculum. To decrease the risks of training residents on patients and to decrease operative time, a program of videoscopic "bench" training exercises, to improve eye-hand coordination, was instituted for junior residents. Between July and September 1995, nine surgical residents participated in this proficiency videoscopic study. At the end of the study, there was a statistically significant improvement in the residents performance by an average of 37% (P = 0.0109). This program proved to be both effective and economical. It can be reproduced and easily incorporated into any surgical residency program.

Clinical Competence↗

PubMed1996

Elective conventional colectomy in the era of laparoscopic surgery.

Laparoscopic surgery, since its introduction into the general surgery, has reduced hospital stay. Can lessons learned from laparoscopic surgery about aggressive postoperative care be applied to elective conventional colectomy? Between August 1994 and February 1995, a prospective study was conducted on 24 consecutive patients undergoing elective conventional colectomy with primary anastomosis. A comparison of 30 consecutive patients in the 7 months immediately before this study were used as a historical control group. Both groups were comparable in age, indications for operation, type of operation, and operative time. The protocol consisted of an outpatient bowel prep, hospital admission on day of surgery, and intravenous metoclopramide starting before the operation and continued every 6 hours with diet started at 24 hours. Patients were discharged on regular diet after a bowel movement and were continued on oral metoclopramide for a total of 7 days. Hospital stay was reduced from 8 days (range 4-19 days) to 4 days (range 2-7 days) on the protocol P < 0.001). Hospital charges were also reduced by 20 per cent (from $18,450 to $14,586) (P = 0.066). Complication rate and postoperative emergency room visits as a measure of quality of care did not differ between the two groups. By implementing this protocol, hospital costs and length of stay for elective conventional colectomy were reduced without compromising patient care.

Adult↗

PubMed1994

Differences in the distribution and characteristics of tachykinin NK1 binding sites between human and guinea pig lung.

1. The distribution and characteristics of tachykinin NK1 binding sites have been compared in human and guinea pig lung using quantitative in vitro receptor autoradiography with [125I]-Bolton Hunter-labelled substance P ([125I]-BH-SP). In addition, the effects on these sites of ovalbumin sensitization and challenge have been determined in guinea pig lung. 2. [125I]-BH-SP bound specifically and with high affinity to microvascular endothelium in both human and guinea pig lung, but to bronchial smooth muscle and pulmonary artery media in only guinea pig lung. 3. Specific binding of [125I]-BH-SP to guinea pig bronchial smooth muscle was positively correlated with airway diameter in the range 150-800 microns and was less dense in trachea than in main bronchi. 4. [125I]-BH-SP binding was inhibited by tachykinins with rank orders of affinity of SP > NKA > NKB (human microvessels) and SP > NKA = NKB (guinea pig bronchi and pulmonary arteries). NKA displayed a higher affinity for [125I]-BH-SP binding sites in human microvessels than in guinea pig tissues (P < 0.0001), indicating differences in selectivity for tachykinins between human and guinea pig NK1 receptors. 5. In both human and guinea pig lung, [125I]-BH-SP binding was inhibited by the specific tachykinin receptor antagonists FK888 (NK1 selective antagonist) and FK224 (mixed NK1/NK2 antagonist), with FK888 displaying equal affinity to SP and > 500 times higher affinity than FK224. SP, NKA, NKB and FK888 exhibited similar affinities for [125I]-BH-SP binding sites in both guinea pig arteries and bronchi. 6. Similar distributions, densities and characteristics of [I251]-BH-SP binding sites were demonstrated in oval bumin-sensitized and -challenged guinea-pig lung and in naive animals.7. Differences in the distribution and characteristics of NKI binding sites labelled with [125I]-BH-SP between guinea pig and human lung suggest limitations in the use of guinea pig models for studying roles of tachykinins in pulmonary disease. However, the similar microvascular distributions of NK,binding sites in human and guinea pig lung suggest that the selective tachykinin receptor antagonistsFK888 and FK224 may be useful in the management of airway inflammation in man.

Animals↗