[show abstract][hide abstract] ABSTRACT: The treatment of digital ischemia in systemic sclerosis remains inadequate. We report a double blind, placebo controlled trial of recombinant tissue plasminogen activator (rtPA), a potent thrombolytic agent. Ten patients received rtPA. A potent, acute fibrinolytic effect was observed. During the infusion of rtPA, improvements in skin blood flow were seen. These improvements were shortlived.
The Journal of Rheumatology 06/1992; 19(5):716-20. · 3.26 Impact Factor
[show abstract][hide abstract] ABSTRACT: The scattering and absorption of light by tissue and blood is wavelength dependent; the tissue penetration of green light (lambda = 543.5 nm) is about 60 per cent of that of red light (lambda = 632.8 nm) but the absorption of green light by blood is about 20 times greater than for red light. The effect of this difference has been studied by observing the responses of skin blood flow to heat and weal, measured by laser Doppler flowmetry at the two wavelengths. By using time autocorrelation function analysis (ACF) of the scattered light measured, low and high frequency components have been associated with capillary and larger vessel flow, respectively. The comparison of ACF from scattered green and red light has shown that measurements cannot be interpreted by only considering light penetration depth through a homogeneous tissue. Light absorption and multiple scattering by blood at the individual microvessel level, blood rheology and vessel morphology are parameters which are considered for greater attention.
[show abstract][hide abstract] ABSTRACT: Hand skin blood flow in 32 insulin-dependent (IDDM) diabetics was compared with 13 healthy controls at room temperature and after immersion of the hands in warm and cold water. Subjects were examined for limited joint mobility (LJM) to analyse the association between this and blood flow. Digital arteries remained patent in IDDM compared to controls after cold challenge (p = 0.0001), and the difference persisted to a lesser degree 15 min (p = 0.009) and 30 min (p = 0.03) after recovery. Capillary blood flow was reduced in IDDM at room temperature at the finger nailbeds (p less than 0.02) and the palms (p = 0.004) and remained so after warm water immersion in the palms (p = 0.002), where further vasoconstriction was observed immediately after cold water immersion (p less than 0.001) and 15 and 30 min into recovery (p = 0.07 and p = 0.009 respectively). Thermographic analysis confirmed a pattern of predominantly distal rewarming after cold challenge in IDDM with a greater mean index finger temperature than the controls. Together, these features suggested enhanced arteriovenous anastomotic blood flow. All IDDM and IDDM males with LJM had reduced palm capillary flow immediately after cold challenge (p less than 0.05). After warm water (p less than 0.03) and 30 min after cold challenge (p less than 0.05) IDDM males with LJM had reduced palm capillary flow compared to those IDDM without. A microvascular aetiology for LJM is proposed by virtue of reduced nutritional blood flow and evidence of enhanced arteriovenous shunting in the hands of insulin-dependent diabetics.
British journal of rheumatology 07/1989; 28(3):195-200.
[show abstract][hide abstract] ABSTRACT: We have studied the therapeutic effects of ketanserin, a specific serotonin antagonist, on digital ischaemia in 11 patients with the CREST syndrome of systemic sclerosis. Ketanserin was administered as a bolus of 10 mg intravenously, followed by an infusion over 72 h and then oral therapy. Skin blood flow as measured by thermography, bolometry, ultrasound Doppler pulses and laser light scattering, showed significant improvement. There was also marked clinical improvement with a reduction in the pain and healing of digital ulceration. These improvements were maintained on oral therapy. In 7 patients detailed studies were performed comparing oral and intravenous ketanserin therapy. When ketanserin was administered as a bolus 10 mg intravenous dose, followed by an infusion at 2 mg/h, steady state was reached by 12 h. Following oral treatment (40 mg tds) therapeutic blood levels were achieved.
Scandinavian Journal of Rheumatology 02/1989; 18(2):107-11. · 2.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: Disturbed upper limb skin blood flow has been described in insulin-dependent (Type 1) diabetes mellitus, but the pathophysiological mechanism remains unclear. Hand skin blood flow was therefore measured at room temperature and following immersion of hands in cold and warm water in 13 healthy control subjects, in 10 patients with Type 1 diabetes mellitus and cardiovascular autonomic neuropathy, and a further 10 Type 1 diabetic patients with normal cardiovascular autonomic tone. Following cold challenge there was failure of digital artery clampdown in all diabetic patients in comparison with healthy control subjects (p less than 0.005), and the index finger temperature fell less (p less than 0.05). Laser Doppler flow was reduced at the palms at room temperature or following the warm challenge (p less than 0.008), as well as on the dorsum at room temperature (p less than 0.05), in all diabetic patients. In addition laser Doppler flow in the diabetic patients was reduced at the palms and dorsum immediately following cold water challenge (p less than 0.004) and this reduction persisted 15 min (p less than 0.05) and 30 min (p less than 0.01) into the recovery phase. In comparison to those diabetic patients with normal cardiovascular tone, those with cardiovascular autonomic neuropathy had reduced laser Doppler flow at the pulp 15 min after cold water immersion (p less than 0.05), at the nailbed immediately after cold water immersion (p less than 0.01), and at the palms immediately after warm water challenge (p less than 0.01).
Diabetic Medicine 01/1989; 5(9):861-6. · 3.24 Impact Factor
[show abstract][hide abstract] ABSTRACT: Laser Doppler flowmetry with optical-fibre beam transmission is a sensitive fast and convenient method of measuring tissue blood flow. However, its sensitivity can also be a problem because of movement artefacts. This study applies some basic considerations of fibre optics and Rayleigh light scattering to the field of laser Doppler blood flow meters. Practical suggestions are given by which movement arterfacts can be reduced by choice of optical fibres, attention to probe geometry, cladding the fibres to reduce their movements and in the method of application. Experiments which test the normalisation circuitry of laser Doppler instruments are described and the effects of movement artefacts on the interpretation of the pulsatile component of laser Doppler records are also discussed. Probe and fibre line movements cause high-frequency intensity fluctuations due to speckle movement. The intensity fluctuations produce an apparent Doppler shift much greater than the Doppler shift produced by the relative movements of probe and tissue. It has been found that it is important to ensure that the fields of view of the illuminating and detecting fibres do not overlap at the skin surface and that probe contact with the skin surface should be maintained.
[show abstract][hide abstract] ABSTRACT: Measurements of peripheral blood flow using bolometry, thermography, ultrasonic Doppler index, and laser light scattering were made in nine patients with primary Raynaud's phenomenon before and after administration of 20 mg sublingual nifedipine and matching placebo. Following nifedipine treatment, there was some evidence of protection against reduction in blood flow, suggesting that this way of taking nifedipine is helpful. Self-administration of sublingual nifedipine before cold exposure may be an effective way of preventing the development of attacks of Raynaud's phenomenon in contrast with the conventional form of regular oral administration.
Journal of Cardiovascular Pharmacology 06/1987; 9(5):628-31. · 2.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ketanserin, 40 mg b.i.d., or matching placebo were administered for 8 weeks each in a randomised double-blind crossover design to 23 patients with Raynaud's phenomenon. Ketanserin had no effect on Doppler arterial patency or blood flow at rest, 37 degrees C, 15 degrees C, or during recovery after cold challenge. Red cell deformability index and whole blood viscosity were not significantly affected by ketanserin treatment. In vivo bleeding time was prolonged on ketanserin (p less than 0.05) but beta-thromboglobulin and platelet factor 4 were unaffected. There was a nonsignificant decrease in platelet aggregation response to serotonin but no change at all with other aggregating agents on treatment with ketanserin.
[show abstract][hide abstract] ABSTRACT: Studies of both intensity and Doppler shifted linewidths of light scattered from skin tissue have been made using photon correlation spectroscopy and optical fibre techniques. Measurements as a function of the separation of input and detecting fibre positions show characteristic features. These features are interpreted in terms of the positions of the scattering red blood cells and the tissue structure. Evidence is given for an interpretation of the differences in the scattered light for scattering from superficial vessels including capillary loops and from deeper lying larger vessels and shunts. Measurements using various laser wavelengths are discussed. The results of this study are important in the development of laser light scattering instruments for the measurement of peripheral blood flow and microcirculation.
Physics in Medicine and Biology 01/1985; 29(12):1463-76. · 2.70 Impact Factor