Biomedical subjects
K Lafferty
Publications and source records attributed to K Lafferty.
Natural progesterone and antihypertensive action.
In a placebo controlled, double blind crossover study natural progesterone was given by mouth, in increasing doses, to six men and four postmenopausal women with mild to moderate hypertension who were not receiving any other antihypertensive drugs. When compared with values recorded before treatment and during administration of placebo progesterone caused a significant reduction in blood pressure, suggesting that progesterone has an antihypertensive action rather than a hypertensive one as has been previously thought. This possible protective effect of progesterone should be investigated further.
Reflex vascular responses in the finger to contralateral thermal stimuli during the normal menstrual cycle: a hormonal basis to Raynaud's phenomenon?
1. Raynaud's phenomenon is a condition which primarily affects women and it must be assumed that hormonal influences are responsible. 2. To further investigate this assumption the effect of cyclic sex hormone fluctuations on the digital vascular reactivity of ten normal young women was studied by the diagnostic techniques of thermal entrainment of finger blood flow and Doppler ultrasound mapping of the digital arteries. 3. In the immediate pre-ovulatory period the results obtained were comparable with those found in patients with established Raynaud's phenomenon, suggesting that oestrogen has an important modulating effect in vivo on reflex peripheral vasomotor responses to thermal stimuli. 4. 'Primary' Raynaud's phenomenon may represent an exaggerated response to oestrogen.
Non-invasive location of arterial stenoses.
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What does photoplethysmography measure?
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Thermal entrainment and human ovulation.
The changes in the peripheral vascular response to temperature have been studied for ten menstrual cycles by calculating thermal entertainment levels. The entrainment levels exhibited peaks at around the time of ovulation, a result which we believe is due to the fluctuating levels of the hormones oestrogen and progesterone in the blood. An attempt has been made to explain the influence of these hormones on the vasomotor control system and where interactions may occur.
Peripheral vasomotor control and menopausal flushing--a preliminary report.
Menopausal flushing can be considered as an intermittent loss of peripheral vasomotor control. Thermal entrainment testing has been used to assess the degree of peripheral vasomotor control in a preliminary study of seven women receiving oestrogen replacement therapy in the form of percutaneous cream. Significant improvement was demonstrated in the degree of control over a 3-month period in those patients who were symptomatically improved. We suggest that oestrogen exerts an influence on peripheral vasomotor control and flushes and sweats occur when this influence is removed.
On the nature of Raynaud's phenomenon: the role of histamine.
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Raynaud's phenomenon: prostacyclin or histamine deficiency?
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Raynaud's phenomenon and thermal entrainment: an objective test.
A new objective test for diagnosing Raynaud's phenomenon was assessed in practice. The test is based on entrainment of the thermal vasomotor control system and entails non-invasive measurement of blood-flow responses in one hand while alternating thermal stimuli are applied to the contralateral hand. A significant (p less than 0.001) abnormality of vasomotor control was found in patients with Raynaud's phenomenon compared with normal subjects. When applied clinically this test is diagnostic and indicates the severity of the disease and the effect of treatment.
Necrotising enterocolitis in small bowel atresia.
A retrospective study of 76 infants with small bowel atresia treated in two neonatal surgical units between 1970 and 1979 is presented. The overall survival rate was 75% and there was no significant difference between the two centres. The mortality rose according to the number of atresias and the distance of the first atresia from the ileo-caecal valve. The 19 deaths were classified as inevitable or avoidable. Of the latter group, 5 out of 14 deaths were due to neonatal necrotising enterocolitis, and the remainder to respiratory problems associated with prematurity or to surgical complications producing peritonitis and septicaemia.
Differences in the graft-versus-host reactivity of cells migrating through nonlymphoid tissue or lymph nodes.
Normal lymphocyte transfer reactions have been used to test the alloreactivity of lymphocytes which have migrated through lymph nodes (i.e., in efferent lymph) or nonlymphoid tissues (i.e., in afferent lymph) in sheep. Lymphocytes from afferent lymph are much less efficient at inducing a normal lymphocyte transfer lesion than lymphocytes from efferent lymph. Afferent cell preparations (which contain about 10% macrophages) do, however, cause a greater inflammatory response in the early part of the reaction, but this is at least partly nonspecific. A mixture of afferent and efferent cells produces a lesion which is simply the sum of the two expected reactions, suggesting that the afferent lymphocytes are not merely inhibited by a factor or cell in the preparation.
An improved system for the assay of stimulation in mouse mixed leucocyte cultures.
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Clinical tutor and contract monitoring: a candle in the wind.
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