Reliability of blood pressure determination with the Finapres with altered physiological states or pharmacodynamic conditions

The blood pressure waveform is modified on distal propagation by phenomena such as dispersion, reflection and the state of the arterial compliance. The consequent effects are amplification and narrowing of the wave, with an increased systolic, reduced diastolic and essentially unaltered mean blood pressure. The Finapres measures the peripheral pressure using the volume clamp principle; it has not been validated under altered physiological conditions and during pharmacodynamic interventions. We studied simultaneous Finapres and brachial blood pressures (using a conventional oscillometric sphygmomanometer—Vitalmap) in ten normal volunteers at rest, and during dynamic exercise and a cold pressor test. The effects of pharmacodynamic intervention were examined following beta-adrenoceptor blockade with propranolol (160 mg) or beta-adrenoceptor modulation with the beta-adrenoceptor partial agonist celiprolol (400 mg). The Finapres systolic pressure was significantly higher than the brachial value during all three test states. The difference between the systolic pressures measured by the two devices was shown to increase significantly during the cold pressor test, but not during dynamic (supine bicycle) exercise. The Finapres diastolic pressure was significantly higher than the Vitalmap value during exercise and the cold pressor test. The differences between the two methods increased significantly over time. Beta-adrenergic blockade with propranolol or modulation with celiprolol had no significant interaction with the pressure differences between the Finapres and Vitalmap techniques. The results would support the view that the Finapres can provide blood pressure information which is robust under most circumstances. Although this pharmacodynamic intervention did not alter the relationship between the peripheral and central blood pressure, it is important to note that this dynamic relationship is sensitive to circulatory loading conditions and wave transmission characteristics; it is possible that the Finapres could be less reliable in clinical settings where potent vasoactive agents were being administered.

Design, synthesis and photodynamic antimicrobial activity of ruthenium trischelate diimine complexes

In this study, we describe, for the first time, the synthesis and photophysical and microbiological investigation of ruthenium trischelate diimine complexes designed so as to possess properties specifically suited for use in Photodynamic antimicrobial chemotherapy (PACT). Of the three compounds investigated, one ([Ru(dmob)(3)]Cl-2) has demonstrated considerable promise as a photosensitiser for use in PACT. As a result, this compound is now the subject of comprehensive chemical, toxicological and formulation studies.

Substance P induces histamine release from human pulmonary mast cells.

Substance P elicits histamine release from human skin and rodent mast cells. Since neuropeptide-mediated reflexes may be important in asthma, we examined the ability of substance P to stimulate human mast cells obtained at bronchoalveolar lavage (BAL). BAL samples were obtained at routine bronchoscopy from 35 non-preselected patients. Histamine release experiments were performed in a standard manner using substance P and the calcium ionophore A23187. Both substance P (50 μM) and A23187 caused histamine release (median 26.7%, range 6.2–62.8% and 32.1%, 7.7–56.8% respectively) which was significantly greater (P < 0.0001) than the spontaneous release (median 15.6%, range 4.1–33.4%), i.e. that in the absence of any stimulus. Substance P induced histamine release was via an energy dependent process and was blocked by preincubation with antimycin A. A significant correlation was observed between substance P induced release and spontaneous release but was not observed with A23187 induced release. Mast cell counts correlated significantly with substance P induced release but not with spontaneous or A23187 induced release. The substance P induced histamine secretion was elicited at similar concentrations to those used with rodent and human skin mast cells. Asthma is associated with increased numbers of mast cells which have both increased spontaneous and stimulated secretory responses. Thus, in vivo, the bronchoconstrictor action of substance P may in part result from activation of mast cells in the bronchial lumen.

Differential physico-chemical tolerances and intraguild predation among native and invasive amphipods (Crustacea); a field study

We used field surveys and transplant experiments to elucidate the relative roles of physico-chemical regime and intraguild predation in determining the generally mutually exclusive distributions of native and invader freshwater amphipod species. Field surveys showed that the native Gammarus duebeni celticus dominates the shoreline of Lough Neagh, N. Ireland, with some co-occurrence with the N. American invader G. tigrinus. However, the latter species dominates the deeper areas of the mid-Lough. Transplant experiments showed no difference in survival of the native and invader in single species 'bioassay tubes' placed along the shoreline. However, there was significantly higher survival of the invader compared with the native in single species tubes placed in the mid-Lough. In mixed species tubes on the shoreline, the native killed and ate the invader, with no reciprocal interaction, leading to significant reductions of the invader. However, the invader had significantly higher survival than the native in mixed species tubes in the mid-Lough, with no evidence. of predation between the two species. These results indicate that, whereas differential intraguild predation may determine domination of the shoreline by the native, differential physico-chemical tolerances may be major determinants of the domination of the mid-Lough by the invader. This study emphasises the need to consider the habitat template in conjunction with biotic interactions before attempting to draw conclusions about mechanisms determining relative distribution patterns of native and invasive species.

Action research and reflective practice: towards a holistic view

Two concepts that have captured the imagination of the educational community in the last 60 years have been those of ‘reflective practice’ and ‘action research’. Both, in their various forms, are considered to be critical dimensions of the professional development of teachers. However, whilst both were receiving academic attention during the 1930s and 1940s (Lewin, 1934, cited in Adelman, 1993; Lewin, 1946; Dewey, 1933), it was not until Stenhouse’s (1975) notion of the teacher-as-researcher that the two came most compellingly into relationship and educational action research as a process, which held at its centre different kinds of reflection, began to be reformulated in Britain (Carr, 1993). This article considers the important part played in teachers’ development by different kinds of action research. Its central thesis is that, although action research has a critical role to play not least as a means of building the capacity of teachers as researchers of their own practice, there has been insufficient attention given to both the nature of reflection in the action research process, and its relationship to the purposes, processes and outcomes. The article challenges the rational, cognitive models of reflection that are implicit in much of the action research literature. It suggests that more attention needs to be given to the importance of the role of emotion in understanding and developing the capacities for reflection which facilitates personal, professional and ultimately system change.