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1.  Muscles advance the teeth in sand dollars and other sea urchins 
We demonstrate the action of the dental promoter muscles in advancing the continuously growing teeth of sand dollars and sea urchins. Teeth wear at the occlusal end, while new calcite is added to the opposite end. Dental ligaments rigidly hold teeth during chewing, but soften and reform during advancement. The source of forces that advance the teeth was unknown until our discovery of the dental promoter muscles. The muscles, which underly the tooth, attach centrally to the stereom of the pyramid of the Aristotle's lantern (jaw) and peripherally to a membrane that covers the distal end of the tooth. The muscles shorten along an axis nearly parallel to the long axis of the tooth. We stimulated contraction by addition of acetylcholine, with increasing concentrations of acetylcholine generating higher forces. Forces exerted by this muscle are appropriate for its size and are 1000 times lower than forces exerted by interpyramidal muscles that generate chewing forces. In sand dollars, a single muscle contraction of the dental promoter muscle can account for half the mean daily advancement of the teeth.
doi:10.1098/rspb.1997.0211
PMCID: PMC1688700
Echinoidea Urchin Sand Dollar Teeth Morphogenesis Muscle
2.  Locations for renal services--patient satisfaction surveys. 
The Ulster Medical Journal  1998;67(2):110-114.
Renal services have been given priority in recent years in an attempt to align them with levels of provision in other European countries. A survey of patients receiving renal replacement therapy in the Northern Ireland Regional Centre, Belfast, was carried out to ascertain their views on services (survey I). After the establishment of a Northern Health and Social Services Board (NHSSB) sub-regional unit in 1995, the survey was repeated for patients attending the new unit (survey II). In survey I, 53% NHSSB patients responded. Travelling time to and from hospital was a major issue for the majority of patients, with 33% of haemodialysis patients receiving twice weekly treatment unwilling to attend more frequently, even if clinically advised to do so. In survey II, 60% of patients responded. Travel times to the sub-regional unit were significantly shorter and patients felt it provided a similar or better standard of service, compared with the regional centre. All the twice weekly haemodialysis patients would increase to thrice weekly if clinically advised to do so. The study underlines the importance of locating dialysis facilities closer to patients' homes.
PMCID: PMC2448983  PMID: 9885547
3.  Expanding access to coronary artery bypass surgery: who stands to gain? 
British Heart Journal  1995;73(2):129-133.
OBJECTIVE--To determine the perceptions of general practitioners (GPs) about the benefits of coronary artery bypass surgery, in terms of gains in life expectancy, for different groups of patients. DESIGN--A questionnaire survey of all GPs in Northern Ireland. SETTING--A survey conducted collaboratively by the departments of public health medicine in each of the four health boards in the province, serving a total population of 1.5 million. MAIN OUTCOME MEASURES--The median and mean gain in life expectancy perceived by groups of doctors for smoking and non-smoking male and female 55 year old patients. The percentage of 50 year old and 70 year old non-smoking patients considered likely to have their lives extended with bypass surgery. Differences were assessed using the Mann-Whitney U test for unpaired samples and the Wilcoxon signed rank tests for paired. RESULTS--541 GPs replied (response rate 56%). The median (and mean) perceived gain in life expectancy after cardiac surgery for non-smoking 55 year old subjects was 120 (104) months for men and 120 (112) months for women (z = 6.42; P < 0.0001; Wilcoxon signed rank test). For male and female smokers of the same age, the perceived gains were 48 (47) and 60 (52) months respectively (z = 6.72; P < 0.0001; Wilcoxon signed ranks test), both figures being significantly different than for non-smokers. The median (and mean) percentage of patients that the doctors considered would have their lives extended by bypass surgery was 70 (64) of every 100 "young" patients and 40 (42) of every 100 "old" patients, (z = 16.2; P < 0.0001). CONCLUSIONS--These results point to a significant overestimation of the benefits of coronary artery bypass surgery by GPs in Northern Ireland and to a need to develop guidelines for referral.
PMCID: PMC483778  PMID: 7696021
4.  Is choice of general practitioner important for patients having coronary artery investigations? 
Quality in Health Care  1994;3(1):17-22.
OBJECTIVE--To determine whether particular sociodemographic characteristics of patients with stable angina affected their general practitioners' (GPs') decisions to refer them for revascularisation assessment. DESIGN--Postal questionnaire survey. SETTING--Collaborative survey by the departments of public health medicine in each of the four health boards in Northern Ireland, serving a total population of 1.5 million. SUBJECTS--All (962) GPs. MAIN MEASURES--The relation between GPs' referral decisions and patients' age, sex, employment status, home circumstances, smoking habits, and obesity. RESULTS--541 GPs replied (response rate 56%). Most were "neutral" towards a patient's sex (428, 79%), weight (331, 61%), smoking habit (302, 56%), employment status (431, 80%), and home circumstances (408, 75%) in making decisions about referral. In assigning priority for surgery most were neutral towards the patient's sex (459, 85%), employment status (378, 70%), and home circumstances (295, 55%). However, most GPs (518, 95%) said that younger patients were more likely to be referred, and a significant minority were less likely to refer patients who smoked (202, 37%) and obese patients (175, 32%) and more likely to refer employed patients (97, 18%) and those with dependents (117, 22%) (compared with patients with otherwise comparable clinical characteristics); these views paralleled the priority which GPs assigned these groups. The stated likelihood of referral of young patients was independent of the GPs' belief in ability to benefit from revascularisation, but propensity to refer and perception of benefit were significantly associated for all other patient characteristics. CONCLUSION--GPs' weighting of certain characteristics in reaching decisions about referral for angiography is not uniform and may contribute to unequal access to revascularisation services for certain patient groups.
PMCID: PMC1055177  PMID: 10136255

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