Intravital capillary video-microscopy is a dynamic method for studying skin capillaries. The technique of direct intravital microscopy (without dyes) depends on the presence of red blood cells inside capillaries for their identification. The aim of the present study was to compare different techniques to try to establish the best method for maximizing the number of visible perfused capillaries during intravital capillary microscopy. We compared the effects of venous congestion with those of post-occlusive reactive hyperaemia (Study 1). We also investigated venous congestion followed first by post-occlusive reactive hyperaemia and then by a core heat load test (Study 2). Finally we investigated venous congestion followed by post-occlusive reactive hyperaemia combined with venous congestion (Study 3). In Study 1, capillary density increased with venous congestion from a baseline value of 74±2 (mean±S.E.M.) per field to 82±3 per field (P< 0.0001; analysis of variance). With reactive hyperaemia, there was an apparent decrease in visible capillary density to 69±2 per field. In Study 2, baseline capillary density was 69±4 per field, and this increased significantly with venous congestion to 74±4 per field (P = 0.01). With both reactive hyperaemia and core heat load, the apparent density was 62±4 per field. In Study 3 the baseline density was 70±2 per field, and this increased significantly with venous congestion to 80±3 per field (P< 0.0001). With reactive hyperaemia combined with venous congestion, the density was 81±3 per field (P = 0.328 compared with venous congestion alone). The results show that venous congestion at 60 mmHg for 2 min is the most effective method for visualization of the maximal number of perfused skin capillaries during intravital video-microscopy.
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Research Article|
September 16 1999
Maximization of skin capillaries during intravital video-microscopy in essential hypertension: comparison between venous congestion, reactive hyperaemia and core heat load tests
Tarek F. T. ANTONIOS;
*Blood Pressure Unit, Department of Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
†Clinical Pharmacology Unit, Department of Pharmacology & Clinical Pharmacology, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
Correspondence: Dr Tarek F. T. Antonios (e-mail t.antonios@sghms.ac.uk).
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Fraser E. M. RATTRAY;
Fraser E. M. RATTRAY
*Blood Pressure Unit, Department of Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
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Donald R. J. SINGER;
Donald R. J. SINGER
†Clinical Pharmacology Unit, Department of Pharmacology & Clinical Pharmacology, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
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Nirmala D. MARKANDU;
Nirmala D. MARKANDU
*Blood Pressure Unit, Department of Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
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Peter S. MORTIMER;
Peter S. MORTIMER
‡Dermatology Unit, Department of Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
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Graham A. MACGREGOR
Graham A. MACGREGOR
*Blood Pressure Unit, Department of Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
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Publisher: Portland Press Ltd
Received:
March 11 1999
Revision Received:
May 11 1999
Accepted:
July 22 1999
Online ISSN: 1470-8736
Print ISSN: 0143-5221
The Biochemical Society and the Medical Research Society © 1999
1999
Clin Sci (Lond) (1999) 97 (4): 523–528.
Article history
Received:
March 11 1999
Revision Received:
May 11 1999
Accepted:
July 22 1999
Citation
Tarek F. T. ANTONIOS, Fraser E. M. RATTRAY, Donald R. J. SINGER, Nirmala D. MARKANDU, Peter S. MORTIMER, Graham A. MACGREGOR; Maximization of skin capillaries during intravital video-microscopy in essential hypertension: comparison between venous congestion, reactive hyperaemia and core heat load tests. Clin Sci (Lond) 1 October 1999; 97 (4): 523–528. doi: https://doi.org/10.1042/cs0970523
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