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Biomedical subjects

G Hartley

Publications and source records attributed to G Hartley.

14 recordsLinked to original sources
PubMed1991

Comparative anatomic study of anterior and posterior iliac crests as donor sites.

Ten fixed human cadaver iliums from elderly persons were studied to compare the amounts of graft material present in the anterior and posterior ilium. Average intracortical volume of surgically accessible marrow space was 15.75 mL for the anterior and 39.24 mL for the posterior ilium. Comparison of marrow volume underlying equal surface areas revealed values of 8.4 mL for the anterior and 14.8 mL for the posterior ilium. The average total volume of compressed cancellous bone obtained was 12.87 mL for the anterior and 30.31 mL for the posterior ilium. The ratio of cortical bone window surface area to resultant immediately accessible graft material was 1:0.49 for the anterior and 1:0.75 for the posterior ilium. These results confirm the greater availability of cancellous bone in the posterior ilium.

Aged↗
PubMed1991

The effect of preformed confluent endothelial cell monolayers on the patency and thrombogenicity of small calibre vascular grafts.

Endothelial cell seeding has been proposed as a method to improve the patency rates in small calibre prosthetic vascular grafts. The seeding methods used at present leave much of the graft luminal surface devoid of endothelial cells and thus still significantly thrombogenic. We have developed a method to preform confluent endothelial cell monolayers, on the grafts prior to implantation, and this study investigates the effect of these monolayers on the early thrombogenicity and patency of polytetrafluoroethylene (PTFE) grafts. Small diameter PTFE grafts were seeded with canine endothelial cells obtained from the external jugular vein. Each of five dogs then received a graft seeded with its own cells and a contralateral, non-seeded control graft. At 1 and 10 weeks after graft implantation graft thrombogenicity was assessed by the use of Indium labelled platelets. The thrombogenicity index (TI) of each graft was determined from counts of gamma activity recorded over a period of 7 days. Grafts were subsequently removed at 12 weeks. At 1 week the mean TI for the seeded grafts was 0.123 (SD 0.019) and that for the controls 0.183 (SD 0.017) (p = 0.005). At 10 weeks only the seeded grafts could be assessed because all of the control grafts had occluded. At this point in time the seeded grafts had a mean TI of 0.159 (SD 0.011) (p = 0.047 vs. seeded at 1 week). By the time of removal at 12 weeks, all control grafts were occluded but only one of the seeded grafts had occluded (p = 0.025). In conclusion, the use of preformed, confluent endothelial cell monolayers for seeding prosthetic grafts significantly reduces the early graft thrombogenicity and improves graft patency. It does not, however, completely halt the increase in thrombogenicity which occurs during the early post-implantation period.

Animals↗
PubMed1990

Fine-wire localization and biopsy of non-palpable breast lesions.

We have undertaken fine-wire localization and biopsy of 130 impalpable breast lesions identified by mammography and considered suspicious of malignancy. Histologically 22 of these lesions were invasive carcinomas and 24 were in situ carcinomas (35 per cent malignant). Twenty-nine per cent of the lesions were identified during the screening of asymptomatic women. In the remainder, the presenting symptoms bore no relation to the eventual histological diagnosis. Clusters of microcalcification were more often malignant than were abnormal soft-tissue masses. Malignancy in the absence of microcalcification was almost always invasive.

Biopsy, Needle↗
PubMed1990

Blood pressure, heart rate and neuroendocrine responses to a high carbohydrate and a high fat meal in healthy young subjects.

1. The responses of blood pressure, heart rate, autonomic function and plasma insulin to a high carbohydrate and a high fat meal of equivalent energy value were studied in nine young volunteers. 2. Neither meal produced a significant change in supine or erect blood pressure. The high carbohydrate meal, however, resulted in an overall rise in both supine (6 beats/min) and erect (6 beats/min; P less than 0.05) heart rate, no such changes being seen after the high fat meal. 3. Plasma noradrenaline levels increased by a maximum of 126% at 90 min (0.98 to 2.22 nmol/l) after the high carbohydrate meal but were virtually unchanged after the high fat meal (P less than 0.01). Parasympathetic function showed no between-meal differences. Plasma insulin and glucose levels were significantly higher after the high carbohydrate meal than after the high fat meal. No postprandial difference in packed cell volume was found between meal types. 4. We conclude that, in young subjects, the postprandial blood pressure after a high carbohydrate meal is maintained by an increase in heart rate associated with increased sympathetic nervous system activity. These changes are at variance with the blood pressure and heart rate responses seen in the elderly after a high carbohydrate meal. A high fat meal has no significant cardiovascular or neuroendocrine effects in the young or old. The nutrient composition of meals has to be taken into account when studying the postprandial cardiovascular and neuroendocrine responses in the young.

Adult↗
PubMed1989

Effects of meal composition on the postprandial blood pressure, catecholamine and insulin changes in elderly subjects.

1. The effects of four meals of similar energy, but different nutritional, composition on postprandial blood pressure, heart rate, autonomic function, catecholamines, insulin and packed cell volume levels were studied in seven fit elderly subjects. 2. The high carbohydrate and high protein meals led to a significant overall fall in supine systolic and diastolic blood pressure compared either with no change or a rise after the normal (i.e. mixed) and high fat meals. Similar between-meal differences were seen with erect diastolic but not erect systolic blood pressure. No significant postural blood pressure fall occurred after any of the meals. Supine heart rate was unaffected by meal type or by time, and although erect heart rate showed a small increase during the study there was no between-meal difference. 3. Parasympathetic function was unaffected by meal type. Plasma noradrenaline rose after the high carbohydrate and mixed meals only, remaining elevated for 120 min after meal consumption. This increase was not related to the changes in blood pressure or plasma insulin levels. 4. Plasma insulin and glucose rose after the high carbohydrate and mixed meals, but were unchanged after the high protein and high fat meals. Packed cell volume showed a small decrease towards the end of the study, although there was no between-meal variation. 5. The differences in the cardiovascular changes after the different meals could not be ascribed to alterations in autonomic function, insulin release or fall in plasma volume. We propose that the postprandial changes in blood pressure are due to the nutrient composition of the meal rather than the actual energy load.

Aged↗
PubMed1987

Protective effect of sucralfate against aspirin-induced damage to the human gastric mucosa.

Sucralfate, an agent that heals peptic ulcers in humans, has been shown to reduce aspirin-induced gastric mucosal damage in experimental animals. It has been suggested that the protective effect of sucralfate is due to stimulation of local prostaglandin production. The purpose of this study was to establish whether sucralfate was capable of reducing aspirin-induced gastric damage in humans. The effect of 1 g of sucralfate or identical placebo was studied in random order in eight healthy subjects. To determine if the effect of sucralfate was related to local prostaglandin synthesis, a second series of studies was performed in which prostaglandin production was inhibited with indomethacin 50 mg given orally eight hours before sucralfate. In each subject, all studies were performed at least one week apart. Following an overnight fast, upper gastrointestinal endoscopy was performed, with sucralfate or placebo given orally 30 minutes before ingestion of 1,200 mg of soluble aspirin in 50 ml of water. Both endoscopist and subject were unaware of the test agent. Ninety minutes after aspirin ingestion, endoscopy was again performed and gastric mucosal lesions were counted and graded to derive an erosion score. Results are expressed as mean +/- SEM. Aspirin produced endoscopic changes (score of 2.75 +/- 0.49) that were significantly (p less than 0.05) inhibited by sucralfate (score of 1.13 +/- 0.44). The protective effect of sucralfate was abolished by pretreatment with indomethacin (scores of 2.88 +/- 0.55 and 1.88 +/- 0.40, respectively). These results demonstrate that sucralfate significantly protects the human gastric mucosa against the acute damaging effects of aspirin. This effect is abolished by indomethacin, suggesting that the protective action of sucralfate on the gastric mucosa of humans may be related to stimulation of endogenous prostaglandins.

Aspirin↗
PubMed1986

Multicentre trial of four strategies to reduce use of a radiological test.

The Royal College of Radiologists' guidelines on the use of pre-operative chest X-rays were implemented for 1 year in four hospitals in England and Wales. The strategies adopted were: (1) the appointment of a utilisation review committee; (2) getting feedback on use to consultants; (3) the introduction of a new chest X-ray request form; or (4) the concurrent reviewing of chest X-ray requests by the radiology department. The lowest level of use (8.5 pre-operative chest X-rays per 100 elective operations) was achieved with the utilisation review committee after it displayed the guidelines in surgical wards. Information feedback produced a consistent reduction from 29.4 to 13.3 X-rays per 100 operations. Both the new request form and concurrent review had a moderate and intermittent effect. No change in practice occurred in a control hospital.

England↗
PubMed1976

Screening for breast cancer.

The feasibility of mass population screening for breast cancer by clinical examination and x-ray mammography was studied. The results indicate that such a programme could be conducted effectively by non-medical staff and be safe from the dangers of irradiation. The response rate of women invited for screening suggests that such a service is acceptable to the general public. The additional work load produced by screening would not overburden the existing surgical services.

Aged↗