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Biomedical subjects

B Parsons

Publications and source records attributed to B Parsons.

65 records · Page 4Linked to original sources
PubMed1981

Sequential inhibition of sexual receptivity by progesterone is prevented by a protein synthesis inhibitor and is not causally related to decreased levels of hypothalamic progestin receptors in the female rat.

In the estrogen-primed ovariectomized female rat, the administration of progesterone facilitates sexual receptivity and activates proceptivity for many hours. If the progesterone dose is large (e.g., 2.5 mg), a refractory period follows, during which time animals are less sensitive to additional progesterone. This refractory period has been termed "sequential inhibition" and has been correlated previously with decreased levels of cytosol progestin receptors in the mediobasal hypothalamus-preoptic area (MBH-POA). Our present results indicate that the "sequential inhibition" of mating behavior by progesterone appears to involve a protein synthetic step that is not related causally to decreased levels of cytosol progestin receptors in the MBH-POA. Animals which received subcutaneous injections of the protein synthesis inhibitor, anisomycin (100 mg/kg in saline), 15 min prior to and again 3 hr after progesterone (2.5 mg in propylene glycol) treatment, displayed greater sexual receptivity at 24 hr than did animals which received subcutaneous saline injections. However, cytosol progestin receptor levels in the MBH-POA of animals which received anisomycin plus progesterone were decreased at 24 hr, relative to animals which received saline plus progesterone. Anisomycin did not produce positive or negative behavioral effects at 24 hr when administered 15 min prior to and again 3 hr after propylene glycol, suggesting that the behavioral effects of anisomycin appear to be related to selective blockade of progesterone action. In separate experiments, we administered single subcutaneous injections of anisomycin at various times relative to progesterone (2.5 mg) treatment. According to the time course of effective anisomycin application, the presumed protein synthesis which is responsible for the inhibition of mating behavior occurs between 3 and 13 hr after the administration of progesterone.

Animals↗
PubMed1976

Studies on the intranuclear distribution of human and mouse genomes and formation of human-mouse hybrid cells.

Autoradiographic examination of early hybrid cells formed by the fusion of 3H-thymidine labeled D98/AH2 cells and 3T3-4E cells revealed that human and mouse chromosomes are often separated within metaphase and interphase nuclei. Although the marked separation of human and mouse chromosomes progressively disappeared with succeeding cell division, the occurrence of sectored nuclei in 16-cell hybrid colonies and the labeling pattern of human chromosomes within separated metaphases indicate that separation of human and mouse chromosomes may persist through several mitoses. Fusion of 3H-thymidine labeled D98/AH2 cells and 3T3-4E cells was coupled with aminopterin selection to study other aspects of hybrid cell formation. Hybrid cells arose from heterokaryons by cell division. Nuclear fusion may have occurred in two out of several thousand heterokaryons examined. However, these could reflect the close apposition of adjacent nuclei. A large fraction (greater than 0.5) of D98/3T3 heterokaryons underwent at least one cell division. However, the number of hybrid colonies containing more than eight cells at ten days following fusion was about 0.03 of the total number of heterokaryons. Many hybrid colonies arrested growth before the 8-cell stage, and the cells in such colonies exhibited nuclear abnormalities.

Animals↗
PubMedDate not supplied

The Middlesex University rehabilitation robot.

This paper describes the development of an electrically powered wheelchair-mounted manipulator for use by severely disabled persons. A detailed review is given explaining the specification. It describes the construction of the device and its control architecture. The prototype robot used several gesture recognition and other input systems. The system has been tested on disabled and non-disabled users. They observed that it was easy to use but about 50% slower than comparable systems before design modifications were incorporated. The robot has a payload of greater than 1 kg with a maximum reach of 0.7-0.9 m.

Computer Systems↗
PubMedDate not supplied

The acceptability of pneumococcal vaccine to older persons in Ireland.

A study was carried out to demonstrate in an Irish population whether older persons at risk from pneumococcal disease would accept an offer of the pneumococcal vaccine at the same time as their influenza vaccination. Of the 450 patients from 2 practices invited to attend for vaccination, 367 (81.6%) accepted both vaccines, a further 17 (3.8%) accepted the influenza vaccine only and a further 3 (0.7%) accepted the pneumococcal vaccine only. Three hundred and seven (68.2%) patients had received influenza vaccine at some time in previous years and these were statistically more likely to accept either vaccine than those who had not. This study has demonstrated that older persons at risk from pneumococcal disease will respond positively to a written invitation from their GP to avail of the pneumococcal vaccine.

Aged↗
PubMedDate not supplied

Ask trustees who know. Interview by Laurie Larson.

Five of your trustee peers share their expertise on board education, fundraising, community representation, what it means to be a board chair, and what physicians can bring to your board.

Community Participation↗