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Biomedical subjects

N Harrison

Publications and source records attributed to N Harrison.

At least 55 records · Page 3Linked to original sources
PubMed1992

Appropriate use of local anaesthetic for venous cannulation.

A departmental survey indicated that the large majority of anaesthetists believed that injection of local anaesthetic before insertion of an intravenous cannula was unnecessary if a cannula of 18 gauge or smaller was used, because injection of local anaesthetic would be more painful than insertion of the cannula. A study was undertaken to test this hypothesis. The results showed that intravenous cannulation with a cannula of 18, 20 or 22 gauge was significantly (p less than 0.006) more painful than a subcutaneous injection of 1% lignocaine. We recommend that subcutaneous injection of local anaesthetic should be considered before insertion of any size of intravenous cannula.

Adult↗
PubMed1991

Mandible reconstruction with vascularized bone grafts. A histologic evaluation.

To our knowledge, a histologic evaluation of bone healing after mandible reconstruction with vascularized human bone grafts has not been previously reported. Serial sections through both the decalcified graft and the junction between mandible and graft were evaluated in four patients who required surgical removal of their reconstructed mandibles. A failed scapular bone graft that had been wrapped within a pectoralis major myocutaneous flap for salvage following pedicle thrombosis showed markedly resorbed but viable bone with a fibrous union to the native mandible. Viable vascularized grafts without evidence of ongoing resorption characterized an iliac osteocutaneous bone graft and two scapula osteocutaneous grafts that healed with continuity of healthy bone between graft and mandible. Observations from the evaluation of these specimens are made regarding bone circulation, bone union, and bone graft survival as they occur clinically. Implications regarding the techniques of bone plating and indications for use of vascularized bone in mandible reconstruction are discussed.

Bone Transplantation↗
PubMed1990

Cardiopulmonary effects of a brief exposure to cigarette smoke in the guinea pig.

To investigate whether the acute inflammatory response produced by acute cigarette smoke exposure is associated with alterations in pulmonary and cardiovascular function, using a respirator we exposed 8 guinea pigs to 350 ml of cigarette smoke diluted in 2,000 ml room air for 10 min. Lung volumes, pressure volume curves and flow volume curves were performed. Measurements of pulmonary artery pressure, systemic pressure, heart rate and cardiac output were taken at baseline, immediately after the smoke exposure, and 1.5 h after smoke exposure. Aliquots of peripheral blood for total white cell count and differential count were obtained. After animal sacrifice, the right lung was lavaged and white cell count and differential count performed. We found that acute exposure to cigarette smoke produced a peripheral blood neutrophilia which rose progressively from a baseline of 36.3 +/- 8% to a maximum of 72.2 +/- 7.7% at 1.5 h after exposure. There was pulmonary neutrophilia with 24.6 +/- 6.3% neutrophils in the lavage fluid of the smoke-exposed animals compared to 8.4 +/- 4.3% in the control animals. Immediately after smoke exposure, there was acute airflow obstruction with a decrease in the peak flow and forced expiratory flow between 25-75% vital capacity. This was associated with airtrapping, as shown by a transient increase in residual volume. There was a slight decrease in systemic blood pressure in the smoke-exposed animals associated with a nonsignificant decrease in the heart rate, and the cardiac output remained stable.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗
PubMed1988

Quartz but not iron oxide causes air-flow obstruction, emphysema, and small airways lesions in the rat.

Recent epidemiologic studies have suggested that some workers exposed to inorganic dusts develop air-flow obstruction independent of or greater than that produced by cigarette smoke; the morphologic basis of this effect is unknown. To investigate this problem, we administered saline alone, 10 mg iron oxide (an inert dust), or 10 or 30 mg of quartz to rats by intratracheal instillation. Animals were killed after 30 days, and pulmonary function and morphologic changes were examined. The iron oxide group was similar to the saline control group in all functional and morphometric parameters. However, both quartz-exposed groups showed evidence of air-flow obstruction, with more severe abnormalities in the high dose group. These findings correlated with morphometric observations of emphysema and thickened airway walls, with changes again more severe in the high dose group. Early silicotic nodules were also present in the latter animals. We conclude that in addition to the classic lesions of nodular silicosis, quartz can produce morphologic and functional changes of air-flow obstruction; no such changes are seen with iron oxide. These observations may explain the air-flow obstruction seen in workers exposed to mineral dusts.

Airway Obstruction↗
PubMed1987

Cigarette smoke makes airway and early parenchymal asbestos-induced lung disease worse in the guinea pig.

In order to assess the effects of cigarette smoke and asbestos exposure, we divided guinea pigs into 4 groups: smoking or nonsmoking, and asbestos-exposed or not asbestos-exposed groups. Asbestos-exposed animals were given a single intratracheal instillation of 5 mg UICC amosite, a dose and method of administration that we have previously shown produces morphologic changes in the small airways as well as minimal interstitial fibrosis. Animals were smoked 5 days per week for 6 months. By itself, smoking did not affect lung collagen content, small airways wall thickness, or the volume fraction of tissue surrounding airways, but it did cause a significant increase in alveolar mean linear intercept (Lm). Asbestos alone increased collagen content, airway wall thickness, and tissue volume fraction surrounding airways, the latter measure used to assess interstitial fibrosis. An unexpected finding was that asbestos also increased Lm. The two agents administered together caused more severe changes of all types than were produced by either agent alone, and the interaction between the 2 was generally synergistic. Smoke-exposed animals retained 3 times the asbestos fiber burden of those not smoke-exposed; the increase in retention was greater for short than for long fibers. We conclude that cigarette smoke can potentiate the fibrosis induced by asbestos, possibly because of increased fiber retention. As well, in this model, asbestos or asbestos plus cigarette smoke produces increases in alveolar size.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

A pilot study of the multidisciplinary management of childhood asthma in a family practice.

A small, controlled trial of joint treatment of childhood asthma by a doctor, a physiotherapist, a psychologist, and a social worker, working together in the family setting, demonstrated an improvement in ventilatory capacity. The limited scope of this trial does not permit more general conclusions as to the effect of such treatment on the severity and frequency of attacks, but the observation that some measurable physiological improvement occurred suggests that the place of multidisciplinary nonpharmaceutical management of childhood asthma should be investigated in more detail.

Adolescent↗
PubMed1974

Surgical reduction of tumour bulk in management of abdominal Burkitt's lymphoma.

The results of a retrospective study of the value of reductive surgery in the treatment of abdominal Burkitt's lymphoma are reported. Nine patients had almost complete removal of the tumour, 16 had little over half of the tumour removed, and 43 underwent biopsy only. All patients subsequently received chemotherapy. There was a highly significant difference in the proportion of patients achieving a sustained durable remission (P > 0.0001) and a significant difference in survival (P > 0.05) between the group having almost complete removal and the partial resection group. Partial resection gave no advantage over no surgery. We believe that whenever possible complete removal of the abdominal tumour should be attempted regardless of the presence of extra-abdominal tumour; but unless at least 90% of the tumour can be removed there is no advantage in partial resection in terms of response to subsequent chemotherapy. In particular the removal of one of two involved ovaries can no longer be recommended. The implications of these results are related to cancer treatment strategy.

Abdominal Neoplasms↗
PubMedDate not supplied

Changes in concentration of five PCDD/F congeners after cooking beef from treated cattle.

A large piece of meat taken from a single animal, which had been dosed with five selected PCDD/Fs, was prepared and cooked by a selection of different methods; burgers (fried, grilled, barbecued), roasts (cooked using conventional and microwave ovens) and stews (open pan and pressure cooked). For some of the cooking methods, concentration changes, on a whole product basis, were observed between raw and cooked product. However, in all cases these could be explained simply through changes arising from loss of water and elimination of PCDD/Fs with released fat. The total amounts of PCDD/Fs present in the system (including in released fat) remained unchanged. Dietary intake of PCDD/Fs could therefore be reduced by the removal of visible fat from meat before cooking and by discarding any fat released from foods during the cooking process.

Adipose Tissue↗
PubMedDate not supplied

Concentration changes for 5 PCDD/F congeners after administration in beef cattle.

Ten cattle were treated with daily doses of five PCDD/F congeners, over a 4 week period. Four control animals were not treated. They were subsequently slaughtered as three groups, at 5, 18 and 31 weeks after the first dose. All congeners showed an increase in concentration within animal tissues when sampled at 5 weeks post-dosing. Concentrations had reduced after 18 weeks and there was a further small reduction after 31 weeks. Halflives for each congener were calculated at 13-21 weeks (93-148 days). Concentrations of congeners were different in the various tissues analysed. At 5 weeks after dosing commenced, concentrations in sub-cutaneous fat and in perirenal fat were close to 40 ng/kg (a predicted level based on 50% absorption of the dosed compounds). Concentrations on a fat basis in muscle tissue and liver were, however, about 5 and 10 times higher, respectively. The concentrations found in muscle tissue and liver samples taken at 18 and 31 weeks were approximately twice that found in fat deposits, thus the differences were still apparent, but at a reduced level. It is possible that the distribution phase was incomplete and that PCDD/Fs remained predominantly in association with circulating blood lipids rather than in equilibrium with depot fat. It follows that if livestock were recently exposed to PCDD/Fs (for example, through the consumption of contaminated feed), the analysis of depot fats would not necessarily provide a reliable indicator of the concentrations of PCDD/Fs in edible tissues.

Absorption↗
PubMedDate not supplied

Time trends in human dietary exposure to PCDDs, PCDFs and PCBs in the UK.

Total Diet Study samples collected in 1982 and 1992 were analysed. Estimated dietary intakes of PCDDs, PCDFs and PCBs by UK consumers were found to have fallen substantially during this period and are now considerably below the Tolerable Daily Intake (TDI). Composite samples of human milk were also analysed for PCDDs, PCDFs and PCBs. Estimated combined dietary intakes of PCDDs, PCDFs and PCBs by breast fed infants in 1993-94 via breast milk fell from 170 pg TEQ/kg bodyweight/day at 2 months to 39 pg TEQ/kg bodyweight/day at 10 months.

Adolescent↗