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4 results on '"Hennis Phillip"'

1. Changes in labial capillary density on ascent to and descent from high altitude [version 1; referees: 2 approved]

Author

Edward Gilbert-Kawai, Jonny Coppel, Hennis Phillip, Michael Grocott, Can Ince, and Daniel Martin

Subjects
Airway/Respiratory Physiology, Extrapulmonary Disorders & Therapeutic Interventions, Medicine, Science
Abstract

Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site. Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021). There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017). Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area), despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains elevated on descent to normoxia. The technique is simple, reliable and reproducible.

Published
2016
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2. A pilot study investigating the impact of glycogen storage disease (type III) on skeletal muscle properties and habitual physical activity patterns in young and middle-aged adults

Author

Tomlinson, David, Hennis, Phillip, Murphy, Elaine, Tomlinson, David, Hennis, Phillip, and Murphy, Elaine

Abstract

Glycogen storage disease type III (GSDIII) is an autosomal recessive condition, characterised by skeletal muscle (SM) impairment leading to functional limitations. Previous research has identified both handgrip strength to decline following the age of 37 and sit-to-stand time to increase post 30 years old (Decostre et al., 2017, Molecular genetics and metabolism, 122, 108-16). However, the age-related drop in SM strength is noted to be more prominent in loaded antigravity SM in comparison to the upper extremities (Delmonico et al., 2009, American Journal Clinical Nutrition, 90, 1579-1585) and may not adequately detail the impact of GSDIII on SM and physical function. Therefore, the aim of this study is to preliminary detail the impact of GSDIII on antigravity SM properties and investigate habitual physical activity (PA) patterns that may contribute to a loss strength. With institutional and NHS ethics approval, five participants were recruited and categorised into two age groups (Mean±SD: <30yrs (n=2) age: 27±1; body mass 76.9±5.2kg; ≥30yrs (n=3) age: 49±3; body mass 76.5±6.1kg). Group differences were examined between body composition assessed by bioelectric impedance, SM structural properties by ultrasonography (vastus lateralis muscle thickness (VLMT), pennation angle and fascicle length), knee extensor strength by isokinetic dynamometry (isometric maximum voluntary contraction (iMVC) at 80°) and PA patterns using thigh-mounted 3D accelerometry undertaken for 7 days. Primarily, the ≥30yrs group had 52% higher body fat% and 16% lower lean mass, supporting the theory of a drop in physical function post 30yrs of age. Similarly, SM structural differences, revealed the ≥30yrs group to have 17.7% lower VLMT (2.03cm vs. 1.67cm), 5.6% decrease in pennation angle (15.9° vs. 15°), yet 7.5% greater fascicle length (6.7cm vs. 7.2cm). Interestingly though, knee extensor iMVC was 78% lower (225Nm vs. 49Nm) in the ≥30yrs group, in conjunction with 75% lower relative strength (i

Published
2018

3. Changes in labial capillary density on ascent to and descent from high altitude

Author

Jonny Coppel, Edward Gilbert-Kawai, Daniel Martin, Hennis Phillip, Can Ince, Michael P.W. Grocott, Amsterdam Cardiovascular Sciences, and Translational Physiology

Subjects
medicine.medical_specialty, Correlation coefficient, Wilcoxon signed-rank test, Physiology, Airway/Respiratory Physiology, 030204 cardiovascular system & hematology, Biology, General Biochemistry, Genetics and Molecular Biology, Microcirculation, Extrapulmonary Disorders & Therapeutic Interventions, 03 medical and health sciences, 0302 clinical medicine, Internal medicine, medicine, General Pharmacology, Toxicology and Pharmaceutics, Rank correlation, Microscopy, General Immunology and Microbiology, Altitude, Articles, General Medicine, Effects of high altitude on humans, Capillaries, Oxygen, Capillary density, Cardiology, Hypobaric hypoxia, Analysis of variance, 030217 neurology & neurosurgery, Research Article
Abstract

Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site. Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021). There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017). Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area), despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains elevated on descent to normoxia. The technique is simple, reliable and reproducible.

Published
2016

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