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Biomedical subjects

A J Handley

Publications and source records attributed to A J Handley.

At least 19 recordsLinked to original sources
PubMed1998

HIV-1 selection by epidermal dendritic cells during transmission across human skin.

Macrophage tropic HIV-1 is predominant during the initial viremia after person to person transmission of HIV-1 (Zhu, T., H. Mo, N. Wang, D.S. Nam, Y. Cao, R.A. Koup, and D.D. Ho. 1993. Science. 261:1179-1181.), and this selection may occur during virus entry and carriage to the lymphoid tissue. Human skin explants were used to model HIV-1 selection that may occur at the skin or mucosal surface. Macrophage tropic, but not T cell line tropic strains of HIV-1 applied to the abraded epidermis were recovered from the cells emigrating from the skin explants. Dermis and epidermis were separated by dispase digestion after virus exposure to determine the site of viral selection within the skin. Uptake and transmission to T cells of all HIV-1 isolates was found with the dermal emigrant cells, but only macrophage tropic virus was transferred by emigrants from the epidermis exposed to HIV-1, indicating selection only within the epidermis. CD3+, CD4+ T cells were found in both the dermal and epidermal emigrant cells. After cell sorting to exclude contaminating T cells, macrophage tropic HIV-1 was found in both the dermal emigrant dendritic cells and in dendritic cells sorted from the epidermal emigrants. These observations suggest that selective infection of the immature epidermal dendritic cells represents the cellular mechanism that limits the initial viremia to HIV-1 that can use the CCR5 coreceptor.

CD4-Positive T-Lymphocytes↗
PubMed1998

Four-step CPR--improving skill retention.

This study is an attempt to see if simplifying the teaching of basic life support leads to better skill acquisition and retention. Forty-eight lay volunteers received instruction in CPR; 24 were taught the standard 8-step sequence whereas 24 were taught a simplified 4-step sequence. Tests of performance were carried out on a manikin before and after training. Those in the 4-step group were significantly better than those in the 8-step group at remembering the sequence of skills immediately after training (P = 0.04), 1 week later (P < 0.001) and at 6 weeks (P < 0.001). Twenty-three out of the 24 volunteers in the 4-step group got the sequence completely correct each time they were tested, in contrast to only 2 out of the 24 in the 8-step group. There was no difference, however, in the quality of performance of the skills between the two groups. In addition, it was shown that use of the 4-step sequence should result in a useful reduction in the time taken before a rescuer calls for the emergency services and commences CPR. Whether such a radical change in teaching should be introduced is a matter for further discussion and research.

Adult↗
PubMed1998

A rationale for staged teaching of basic life support.

Basic life support is a crucial part of the Chain of Survival. Unfortunately, however the skill is complex and cannot readily be acquired--let alone retained--in the course of a single training session. Although the problem has long been recognised, no new strategies have been widely implemented to counter the problem. We believe that staged teaching of CPR might provide a solution, and we have devised a program to test this new method. It involves three stages of instruction that we have called bronze, silver, and gold standards. The bronze standard involves opening the airway and providing chest compression without active ventilation: this alone may widen the window of opportunity for successful defibrillation in adult victims in out-of-hospital cardiac arrest. Ventilation is introduced at silver stage using a ratio of 50:5, with emphasis on its value in the resuscitation of children being used as motivation to bring people back for a second period of instruction. The gold stage teaches conventional CPR. A pilot study has been encouraging and a randomized trial on skill acquisition and skill retention is planned.

Adult↗
PubMed1997

Basic life support.

Explore the source record for details and available documents.

Cardiopulmonary Resuscitation↗
PubMed1995

The relationship between rate of chest compression and compression:relaxation ratio.

One of the arguments put forward in support of a relatively fast rate of chest compression during CPR, is that it facilitates the achievement of a high compression:relaxation ratio. This has been shown to increase blood flow. In this study a group of volunteers carried out chest compression at the rate that each felt was correct and comfortable. There was no significant relationship between compression rate and compression:relaxation ratio. In a second study volunteers carried out chest compression on a manikin at rates of 40/min; 60/min; 80/min and 100/min. There was no significant rate related difference in the compression:relaxation ratios recorded. The ability to achieve a high compression duration is not related to compression rate, and should not be a consideration when guidelines on CPR are revised.

Adult↗
PubMed1974

Heparin therapy: a simpler test of control.

A bedside test of heparin activity (whole blood activated partial thromboplastin time) was assessed during clinical control of anticoagulation. It correlated closely (r = 0.94) with the whole blood clotting time but had a number of advantages.

Blood Coagulation Tests↗