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Biomedical subjects

R Scott

Publications and source records attributed to R Scott.

At least 451 records · Page 25Linked to original sources
PubMedDate not supplied

Interactions of substance P antagonists with serotonin in the mouse spinal cord.

Administered intrathecally (IT) to mice, the putative substance P antagonist [D-Pro2,D-Trp7,9-substance P (DPDT) blocked substance P- and serotonin-induced reciprocal hindlimb scratching with ID50 values of 4.6 (2.9-6.9) and 3.0 (1.9-4.8) micrograms, respectively. The duration of this antagonistic effect was 90-120 min. In contrast, DPDT did not block bombesin-, somatostatin-, glycine- or glutamate-induced scratching. These data indicate that DPDT is an effective antagonist of serotonin-induced behaviors in the mouse spinal cord. Phenoxybenzamine (IT) also blocked substance P- and serotonin-induced scratching. Its onset of action was more rapid for serotonin than for DPDT implying differences in agonist-induced receptor activation. Methysergide (IT) blocked serotonin-induced scratching [ID50 = 0.7 (0.3-1.5) micrograms], but not substance P-induced scratching. Similar to DPDT, [D-Arg1,D-Trp7,9,Leu11]-substance P, [des-Arg1,D-Pro2, D-Trp7,9]-substance P(2-11) and [D-Pro4,D-Trp7,9]-substance P(4-11) blocked substance P and serotonin-induced scratching. In contrast, [D-Pro2,D-Phe7,D-Trp9]-substance P and [D-Pro4,D-Trp7,9,10]-substance P(4-11) blocked only substance P-induced scratching. Thus, some, but not all putative substance P antagonists may also be behavioral antagonists of serotonin in the mouse spinal cord.

Animals↗
PubMedDate not supplied

A porcine model of prolonged closed chest venovenous extracorporeal membrane oxygenation.

The sheep has been the standard laboratory animal for extracorporeal membrane oxygenation (ECMO) research for many years and has proven to be an invaluable and reliable model. However the coagulation system of the sheep is significantly different from humans. These differences make it difficult to investigate the coagulative and inflammatory response to ECMO in sheep. The pig has a very similar coagulation system to humans and therefore makes a more appropriate model. We describe a porcine model of prolonged (48 hours) closed chest venovenous (VV) ECMO that we developed to investigate the inflammatory and coagulative response to different ECMO tubing materials. This model could be used to investigate any aspect of venovenous ECMO.

Animals↗
PubMedDate not supplied

Penetration of human spermatozoa through the zona pellucida of nonviable human oocytes.

OBJECTIVE: The purpose of this study was to evaluate the penetrating capacity of human sperm through the intact zonae of nonviable human oocytes and the influence of oocyte storage conditions and gamete coincubation times on penetration rates. METHODS: Immature oocytes were obtained from surgically removed ovarian tissue and from in vitro fertilization (IVF) and subjected to four storage conditions: 1) storage at 4 degrees C for up to 48 hours in culture medium (refrigeration, n = 53), 2) cryopreservation in 1.5 mol/L propanediol with storage at -196 degrees C (PrOH; n = 49), 3) cryopreservation in 2.0 mol/L dimethylsulfoxide with storage at -70 degrees C (DMSO; n = 20), and 4) storage in a hypertonic salt solution at 4 degrees C (salt; n = 30). Semen was obtained from fertile donors (n = 7) and after a wash and swim-up, samples were adjusted to 500,000 motile sperm/mL. Zonae and sperm were coincubated in 100-microL drops under oil, and penetration was assessed at 5 and 20 hours. Penetration was evidenced by visualization of at least one sperm head in the perivitelline space at 200x magnification. RESULTS: Zona penetration rates were 50.9, 32.7, 23.3, and 10.0% for refrigeration, PrOH, salt, and DMSO storage, respectively (P < .004). There was a significantly higher number of sperm in the perivitelline space after 20 hours' coincubation (3.8 +/- 0.2) compared to 5 hours (0.8 +/- 0.1) (P < .0006). This represented an increase in the penetration rate from 31.2% (34 of 109) at 5 hours to 37.6% (41 of 109) at 20 hours, although the difference was not significant. CONCLUSIONS: These results demonstrate that the zona pellucida of nonviable human oocytes can be used in a zona penetration assay and that refrigerated and PrOH-frozen intact zonae have the highest rates of penetration. The decrease in penetrability seen in DMSO and salt-stored oocytes may be due to alterations occurring in the zona pellucida.

Cell Survival↗
PubMedDate not supplied

Training in general (internal) medicine alone.

A freestanding training programme for general (internal) medicine (G(I)M) alone was established in the Oxford deanery four years ago. The programme was designed to provide three years' training post-MRCP for specialist registrars, selected in open competition, and covers all aspects of acute medical care including four months in intensive care. The first four to complete training have achieved consultant level appointments. The programme also attracted a number of trainees who wished to obtain appropriate qualifications in high dependency and critical care medicine. The programme offers the opportunity to create specialists properly trained in G(I)M who will be able to continue to provide an important service as specialists or practising as consultants in G(I)M alone.

Education↗