Telemedicine in the British Antarctic Survey Medical Unit

The system of telemedical care practised by the British Antarctic Survey has developed over a period of 50 years. It is a system that deals with everyday routine medical problems as well as occasional emergencies. It is tried and tested, but undergoes continual modification. Although the Antarctic stations represent a unique setting, the system has the potential for being adapted to many different situations, wherever there are small groups in remote areas needing medical backup. Initial telemedicine work conducted in the Antarctic has led to projects to improve primary care in Scottish communities some distance from specialist centres. As telecommunication links to the Antarctic stations improve, in future the lessons learnt in UK-based projects can be applied in the Antarctic. The evolutionary process will thus continue.

Novel C5a receptor antagonists regulate neutrophil functions in vitro and in vivo

Novel recombinant human C5a receptor antagonists were discovered through modification of the C terminus of C5a. The C5a1-71T1M,C27S,Q71C monomer, (C5aRAM; CGS 27913), was a pure and potent functional antagonist. The importance of a C-terminal cysteine at position 71 to antagonist properties of C5aRAM was confirmed by studying C5a1-71 derivatives with replacements of Q71, C5a derivatives of various lengths (70-74) with C-terminal cysteines, and C5a derivatives of various lengths (71-74) with Q71C replacements. The majority of C5a1-71Q71 derivatives were agonists (C5a-like) in the human neutrophil C5a-induced intracellular calcium mobilization assay. The C5a1-71Q71C derivative was an antagonist. C5a derivatives of lengths 73 and 74 with C-terminal cysteines were agonists, while lengths 70 to 72 were antagonists. C5a derivatives of lengths 72, 73, and 74 with Q71C replacements were agonists, while, again, C5a1-71Q71C was an antagonist. C5aRAM and its adducts, including its dimer, C5aRAD (CGS 32359), were pure antagonists. Additionally, CSaRAM and CSaRAD inhibited binding of 125I-labeled recombinant human C5a to neutrophil membranes (Ki = 79 and 2 pM, respectively), C5a-stimulated neutrophil intracellular calcium mobilization (8 and 13 nM), CD11b integrin up-regulation (10 and 1 nM), superoxide generation (182 and 282 nM), lysozyme release (1 and 2 microM), and chemotaxis (11 and 7 microM). In vivo, intradermal injection of C5aRAM inhibited C5a-induced dermal edema in rabbits. Furthermore, a 5-mg/kg i.v. bolus of C5aRAD significantly inhibited C5a-induced neutropenia in micropigs when challenged with C5a 30 min after C5aRAD administration. C5aRAM and C5aRAD are novel, potent C5a receptor antagonists devoid of agonist or proinflammatory activity with demonstrated efficacy in vitro and in vivo.

Telemedicine in the British Antarctic Survey Medical Unit

The system of telemedical care practised by the British Antarctic Survey has developed over a period of 50 years. It is a system that deals with everyday routine medical problems as well as occasional emergencies. It is tried and tested, but undergoes continual modification. Although the Antarctic stations represent a unique setting, the system has the potential for being adapted to many different situations, wherever there are small groups in remote areas needing medical backup. Initial telemedicine work conducted in the Antarctic has led to projects to improve primary care in Scottish communities some distance from specialist centres. As telecommunication links to the Antarctic stations improve, in future the lessons learnt in UK-based projects can be applied in the Antarctic. The evolutionary process will thus continue.

Establishing a postgraduate qualification in remote health care

The British Antarctic Survey (BAS) provides medical care for the scientists and support staff working on British scientific bases and research vessels in the Antarctic. The BAS directs significant resources towards medical research, so a doctor who does not complete the research component of the programme of training and medical duties represents a partially wasted investment. Additionally, the professional experience gained by the doctor is appropriate for a postgraduate qualification. For these reasons, the training, clinical placement and research undertaken by doctors were formalized as a masters degree in 1992. The objectives of the MSc degree were to optimize the benefits of the training and research for Antarctic doctors and their patients, and to improve the quality of the research output. In the three years before the degree was introduced, only 25% of doctors produced a useful research output. Following the introduction of the MSc, this figure rose to 88%.

Exposure of human vascular smooth muscle cells to Raf-1 antisense oligodeoxynucleotides: cellular responses and pharmacodynamic implications

To characterize the pharmacodynamic properties of CGP 69846A/ISIS 5132, an antisense oligodeoxynucleotide directed against the mitogenic signal transducer Raf-1 kinase, we investigated the elicited biological responses in human coronary artery smooth muscle cells. Cell exposure to CGP 69846A resulted in a reversible time- and concentration-dependent down-regulation of cellular Raf-1 gene expression and, ultimately, inhibition of cell cycle progression. The highest potencies of this compound to reduce Raf-1 mRNA and protein levels were observed after 24 and 48 hr of cell exposure, respectively, with corresponding IC50 values of approximately 100 and approximately 300 nM. Proliferation was inhibited with an IC50 value of approximately 300 nM after 72 hr. We interpreted the recovery rate of Raf-1 mRNA after cell exposure to antisense ODNs as the half-life (t1/2 approximately 50 hr) of active intracellular CGP 69846A in our cell culture system. The endogenous Raf-1 turnover half-life of approximately 30 hr, as assessed by monitoring metabolically labeled Raf-1 protein, correlated kinetically with the antisense-induced protein decay rate (50% decay in approximately 33 hr), indicating that the efficiency of CGP 69846A in decreasing Raf-1 protein levels was rate-limited by the endogenous protein turnover rate. The pharmacodynamic effects of CGP 69846A antisense ODNs are therefore limited by the duration of its intracellular activity rather than by its ability to transiently decrease mRNA levels. Local steady state exposure to CGP 69846A may represent a new approach to prevent the transition of quiescent vascular smooth muscle cells into the pathologically hyperproliferating cells seen after angioplasty.

Night-shift work in Antarctica: sleep characteristics and bright light treatment

Changes in sleep parameters during and after night-shift and the effects of bright white (2500-3000 1x) and dim red (> 500 1x) light treatment on re adaptation after night-shift during winter were studied in 14 men on the British Antarctic Survey Base of Halley (75 degrees south). Subjects kept daily sleep diaries and mood ratings from one week before to three weeks after night-shift and received either full-spectrum white or dim red light treatment from 1100 to 1300 h daily during the first week after night-shift. Plasma melatonin (for 24 h at the end of weeks 1, 2 and 4), and urinary 6-sulfatoxymelatonin (aMT6s, for 48 h weekly) were measured. A significant (MANOVA; p < 0.05) improvement in sleep was seen during night shift (latency and duration) and with bright light treatment (latency). Melatonin and aMT6s rhythms delayed by 7-8 h during night-shift. The white light group readapted slowly, apparently by phase delay, as assessed by aMT6s measurement. The red light group readapted slightly, but significantly (ANOVA, p < 0.01) faster than the white light group.

LTB4-induced transient neutropenia in the rat: a model for evaluating efficacy and bioavailability of LTB4 receptor antagonists

An animal model of leukotriene B4- (LTB4) induced neutropenia has been developed to evaluate LTB4 receptor antagonists in vivo. LTB4, a potent chemotactic inflammatory mediator, when administered intravenously, induces a profound, rapid, and transient redistribution of blood neutrophils from the circulating pool to the marginated pool. This phenomenon is applied in the neutropenia model whereby circulating blood neutrophil counts prior to and after intravenous infusion of LTB4 are compared. Kinetics of LTB4-induced neutrophil responses are determined through the use of a Technicon H*1 automated blood cell analyzer. LTB4 receptor antagonists are identified by inhibition of LTB4-induced neutropenia. Standard antiinflammatory compounds including BW-755C, Abbott A-64077 (zileuton), dexamethasone-21-acetate, indomethacin, and naproxen did not affect LTB4-induced neutropenia. A potent LTB4 receptor antagonist, designated "RPR," inhibited LTB4-induced neutropenia following oral administration in a dose-dependent fashion.

Relationship of blood markers to disease severity and drug efficacy in rat adjuvant arthritis

Rat adjuvant arthritis (AA) was used as a model to evaluate several blood markers as possible predictive indicators of drug efficacy. AA was induced in Sprague-Dawley rats by the injection of complete Freund's adjuvant into the right hind foot pad. The rats were dosed p.o. from day 18 to day 31 with levamisole (10 mg/kg), indomethacin (1 mg/kg), diclofenac sodium (0.5 & 1 mg/kg), and prinomide (10 & 20 mg/kg). Disease severity was assessed by paw circumference on day 31. The following blood markers were analyzed: hyaluronate by ELISA, prostaglandin E2 by RIA, ESR by micro-dispette, total PMN by Technicon H-1, and albumin by BCG dye. Blood marker correlation (r) to disease severity was: hyaluronate (0.71), prostaglandin E2 (0.58), ESR (0.52), PMN (0.58), and albumin (-0.71). The relative rank order of drug efficacy (indomethacin, diclofenac sodium, and prinomide) did not differ using the change in paw circumference (day 31-day 17) or blood markers. Levamisole exacerbated the disease as measured by all the above parameters. Thus, these blood markers provide additional information for the statistical evaluation of drugs in rat adjuvant arthritis.

Invasion of collagen gels by mouse lymphoid cells

Small mouse lymphocytes from lymph nodes rapidly invaded three-dimensional collagen gels (in the absence of any added chemical attractant). In short-term assays (2-8 hr) this property was restricted to 20-25% of the cell population. Invasion was an active process involving cell locomotion. Time-lapse cinematography revealed that movement was erratic with frequent changes in cell speed. Tracks of cell paths within collagen gels demonstrated that lymphocytes made narrow angles of turn and thus showed a 'persistent random-walk' similar to other cell types moving on plane substrata. Analysis of lymphocyte movement within aligned collagen gels demonstrated that locomotion was biased in the axis of fibre alignment, i.e. lymphocytes showed contact guidance. Separated B lymphocytes invaded collagen gels at a slower rate than unseparated lymph node cells, as also did T cells purified by filtration through nylon wool columns. This latter anomaly implied that nylon wool filtration selectively depleted cells with invasive characteristics from a heterogeneous lymphocyte population. A comparison of Peyer's patch and lymph node lymphocytes showed that both populations invaded at the same rate but the latter cell type did this in greater numbers. This difference may reflect the different proportions of B and T lymphocytes in the two tissues. Lymphocytes from oxazolone-stimulated lymph nodes showed greatly increased movement into collagen matrices compared to unstimulated control lymph node lymphocytes. This increase was demonstrated to be a property of the blast cell population by separating the cells on Percoll gradients into lymphoblast-enriched and -depleted populations.