Search PubMed⌕ Search

Biomedical subjects

T L Hooper

Publications and source records attributed to T L Hooper.

At least 73 records · Page 4Linked to original sources
PubMed1988

Preservation of the lung. Comparison of topical cooling and cold crystalloid pulmonary perfusion.

Topical cooling of the lung was compared with cold crystalloid pulmonary artery perfusion with modified Euro-Collins solution in a canine model of unilateral left lung allotransplantation with ligation of the recipient's contralateral pulmonary artery and main bronchus. Lung preservation for 6 hours was achieved by topical cooling and storage at 4 degrees C after absorption atelectasis in five dogs and in a further five dogs by pulmonary arterial perfusion of Euro-Collins solution; 60 ml/kg at 4 degrees C, modified with MgSO4 6 mmol/L followed by storage at 4 degrees C. Dogs in the perfusion group were pretreated with an infusion of the synthetic analog of prostaglandin I2, iloprost (20 ng/kg/min). The ischemic times were 5.97 hours +/- 0.09 for the topical cooling group and 5.96 hours +/- 0.04 for the perfusion group. After transplantation, artificial ventilation at a fixed oxygen concentration was continued until the recipient's death or elective termination of the experiment at 24 hours. Assessment of pulmonary preservation was by animal survival, blood gas analyses, and measurement of lung weight and water in the transplanted lung. No animal in the topical cooling group survived more than 5.5 hours after transplantation; all perfusion recipients survived 24 hours. Oxygenation in the topical cooling group was significantly reduced 1 hour after contralateral ligation: Oxygen tension was 224.2 mm Hg +/- 5.8 before ligation and 92.6 mm Hg +/- 22.3 after ligation (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Two decades' experience with aortic valve replacement with pulmonary autograft.

Aortic valve replacement with a pulmonary autograft was performed on 241 patients between June 1967 and October 1986 at National Heart Hospital, Guy's Hospital, Middlesex Hospital, Harley Street Clinic, and Italian Hospital in London by one of the authors (D.N.R.). The longest follow-up is 18 years 7 months, and the cumulative total follow-up is 1130 patient-years (pt-yr). The overall 30-day mortality rate is 6.6% (16 patients), with no deaths after 1976, and the late mortality rate is 1.7%/pt-yr (19 patients). The actuarial survival rate is 57.3% +/- 9.6% at 19 years. No anticoagulation has been used and there have been no thromboembolic episodes. The incidence of bacterial endocarditis is 1.2%/pt-yr (14 patients), and its actuarial event-free rate is 74.2% +/- 8.1% at 19 years. Reoperation because of failure of the pulmonary autograft was performed on 36 patients, 27 of whom needed valve replacement. The incidence of pulmonary autograft replacement is 2.5%/pt-yr, and its actuarial event-free rate is 48.5% +/- 13.7% at 19 years. For reconstruction of the right ventricular outflow tract, 186 aortic homografts, 26 pulmonary homografts, 16 autologous fascia lata valved conduits, 7 autologous pericardial conduits with or without a valve, and 6 xenograft valved Dacron conduits were used. Thirty-one patients were reoperated on, mostly because of degeneration of this material. Pulmonary rather than aortic homografts are now favored for reconstruction of the right ventricular outflow tract Because of its satisfactory long-term result without the need for anticoagulation, as well as its safety as an established surgical procedure, this operation can be recommended to a wider range of patients.

Actuarial Analysis↗
PubMed1985

Lesser curve disconnection using a stapling device: highly selective vagotomy made quicker and easier.

A stapling device has been used to disconnect the lesser curve of the stomach during highly selective vagotomy in a consecutive series of ten patients. This modification renders the operation technically easier and quicker to perform. Postoperative recovery was uneventful in all patients, and in the subsequent follow-up period of 7-15 months, no problems relating to the technique were encountered.

Duodenal Ulcer↗
PubMed1985

Self-inflicted shotgun wounds of the abdomen.

Three cases of self-inflicted wounds of the abdomen caused by a long-barrelled shotgun are described. The difficulties encountered and the appropriate surgical management are discussed.

Abdominal Injuries↗
PubMed1985

Duodenal ulcer disease in the elderly: a retrospective study.

A retrospective study was performed of 163 patients aged 65 years and over with a diagnosis of duodenal ulceration admitted to one Health District over a period of six years. Eighty per cent of the patients were admitted with acute complications, 50% bled and 30% were perforated. A large proportion of these patients were currently taking anti-inflammatory agents. Patients managed surgically for their complications had a high mortality rate but this was even higher for those managed conservatively. Giant ulcers were found to occur frequently in this age group which had a tendency to severe bleeding. It is concluded that early diagnosis and prompt surgical intervention is essential in the management of complications associated with duodenal ulceration in the elderly.

Aged↗
PubMed1984

Oral urea in the treatment of colo-rectal liver metastases.

A consecutive series of 10 patients with hepatic metastases from colo-rectal carcinoma have been treated with oral urea. This substance has been reported to produce regression of hepatic secondaries from a variety of primary sources including colon. Although well tolerated, and leading to subjective improvement in some patients, no objective benefit has been confirmed from the treatment in this study.

Administration, Oral↗
PubMedDate not supplied

Effects of cardiomyoplasty on cardiac growth in rats.

BACKGROUND AND AIM OF THE STUDY: Cardiomyoplasty (CMP) has been proposed as a treatment for pediatric patients, but restriction of cardiac growth by the muscle wrap is a potential source of concern. This possibility was investigated in an immature animal model. METHODS: Six-week-old rats (body weight 203.8 +/- 5.4 g, mean +/- SEM) underwent either left thoracotomy with CMP (group I, n = 7), or thoracotomy without CMP (group II, n = 8). A third group (group III, n = 7) served as untreated controls. Final measurements were made 20 weeks later after body weights had reached a plateau. RESULTS: Preoperative body weights were not significantly different between the groups. At elective sacrifice, the body weights of animals that underwent surgery did not differ significantly (group I, 558.0 +/- 21.5 g and group II, 617.3 +/- 20.3 g), but were significantly less than those of control animals (727.6 +/- 13.3 g, p < 0.001 and p < 0.01, respectively). Cardiac ventricular weights in the CMP group were significantly less than those of control animals (group I, 1.21 +/- 0.06 g; group III 1.45 +/- 0.04 g; p < 0.01), but were not statistically different from those of the sham thoracotomy group (group II, 1.36 +/- 0.05 g). Mean left ventricular end-diastolic volumes were similar in all groups (group I, 0.67 +/- 0.07 mL; group II, 0.66 +/- 0.07 mL; and group III, 0.69 +/- 0.10 mL; p = ns). CONCLUSIONS: A major surgical procedure impairs growth in juvenile rats. no evidence emerged from this study for additional restriction of cardiac development due to cardiac wrapping. However, studies that include stimulated muscle wraps are needed before CMP should be considered for the pediatric age group.

Animals↗
PubMedDate not supplied

Assessment of skeletal muscle ventricle function using tissue velocity imaging.

BACKGROUND AND AIMS: Skeletal muscle ventricles (SMVs) are a potential power source for circulatory assistance. Noninvasive assessment of SMVs is desirable in long-term studies of SMV function. This study evaluated whether tissue velocity imaging (TVI) indices of function correlate with invasive measurements of output and pressure generation and examined the potential of TVI to provide information about SMV geometry and wall contraction characteristics. METHODS: SMVs were constructed in six sheep. After electrical conditioning, SMVs were connected to a mock circulation and stimulated with supramaximal 30-Hz and 50-Hz bursts to contract 35 times/min. The SMVs were tested over a range of preloads, and afterload was adjusted to simulate systemic (80 mmHg) and right ventricular (30 mmHg) loading conditions. Stroke volume and pressure were measured invasively, and stroke work was calculated. TVI was used to measure velocities in two opposing SMV walls, providing a simple wall motion score (WMS). This was evaluated against stroke volume, stroke work, and pressure development. RESULTS: 50-Hz stimulation frequency and high preload optimized SMV performance. Optimal SMV performance indices (mean at 50 Hz) were as follows: (a) right ventricular loading conditions (preload 30 mmHg), stroke volume 17.6 mL (SEM 3.2), peak pressure over afterload 44.2 mmHg (10.9), stroke work 0.05 J (0.02); (b) systemic loading conditions (preload 60 mmHg), stroke volume 10.1 mL (3.2), peak pressure over afterload 58 mmHg (14.6), stroke work 0.08 J (0.03). With low preloads, geometric anomalies were noted in the SMVs using TVI. Collapse of the SMVs and dyskinesis were observed, which normalized with higher preloads. Persistent dyskinesis was noted in one SMV and was associated with poor performance. Correlations (at optimal loading and stimulation settings) were as follows: systemic loading conditions, stroke volume versus WMS, 0.92 (p = 0.026); peak pressure versus WMS 0.89 (p = 0.045); stroke work versus WMS, r = 0.91 (p = 0.046). Right ventricular loading conditions were as follows: stroke volume versus WMS, 0.63 (p = 0.25); peak pressure versus WMS, 0.66 (p = 0.22); stroke work versus WMS, 0.45 (p = 0.39). CONCLUSION: Under systemic loading conditions, TVI indices of SMV wall motion mirror invasive indices of performance, suggesting that TVI may be a useful tool for long-term noninvasive monitoring of SMV function.

Animals↗
PubMedDate not supplied

Unilateral lung transplantation: ultrastructural studies of ischemia-reperfusion injury and repair in the canine pulmonary vasculature.

UNLABELLED: The left lung was transplanted in 12 adult beagles; the donor lung had been preserved by flush perfusion of the pulmonary artery with 60 ml/kg of Euro-Collins solution at 4 degrees C then stored in Euro-Collins solution at 4 degrees C for 6 hours. Biopsy specimens were taken from control and donor left lungs before and immediately after perfusion, after 6 hours storage, and after transplantation at 4 and 24 hours (total = 46). Tissue from seven animals was injected with the tracer ruthenium red. All tissue was examined by light and electron microscopy. After preservation capillary edema developed, but ruthenium red did not penetrate junction complexes, indicating structurally intact complexes. The proportion of ruthenium red-labeled plasmalemmal vesicles decreased (p less than 0.05). Endothelial cells and type I pneumonocytes because abnormally thin and detached from the basement membrane. The epithelial, but not the endothelial, sheet was disrupted. Four hours after transplantation, edema decreased, and endothelial and epithelial cells regained a more normal shape. The proportion of labeled plasmalemmal vesicles increased (p less than 0.05) by 24 hours, when the value was similar to normal. During preservation, edema formed when alveolar capillary white cell count was normal and decreased after reperfusion when the cells increased threefold (p less than 0.001), indicating that edema was not neutrophil dependent. Many small muscular arteries constricted intensely on cold perfusion. Four hours after transplantation, these abnormalities had improved. CONCLUSION: The pulmonary vasculature showed no evidence that it had sustained additional structural injury after reperfusion. Reperfusion was associated with a gradual resolution of the structural abnormalities incurred during preservation.

Animals↗
PubMedDate not supplied

Preservation of the lung: comparison of flush perfusion with cold modified blood and core cooling by cardiopulmonary bypass.

Clinically applied techniques for lung preservation of flush perfusion with cold modified blood and core cooling by means of cardiopulmonary bypass were compared in a canine model of single left lung transplantation with immediate ligation of the contralateral bronchus and pulmonary artery. In the cold modified blood group (n = 5), after pretreatment with the synthetic prostacyclin analogue iloprost (20 ng/kg/min), lung preservation was achieved by pulmonary artery perfusion with a solution of autologous donor blood, albumin, and mannitol. In the cardiopulmonary bypass group (n = 7), donors were cooled to an esophageal temperature of 10 degrees C before harvest of the heart-lung bloc. Donor organs were stored at 4 degrees C for 6 hours. After transplantation, artificial ventilation at a fixed oxygen concentration was continued until death or until animals were killed at 24 hours. Assessment of lung preservation was by recipient survival, blood gas analyses, and measurement of total lung water content. All cold modified blood recipients survived for 24 hours; four of seven bypass recipients died within 7 hours of operation. There was no change in oxygenation in the cold modified blood group at 1 hour after contralateral ligation: paO2, 212.2 mm Hg +/- 8.5 preligation; 227.2 mm Hg +/- 11.5 postligation. Oxygenation in the bypass group was reduced at 1 hour (paO2, 182.6 +/- 7.6 mm Hg preligation; 139.8 +/- 32.1 mm Hg postligation), but the difference did not reach statistical significance. The difference between groups at 1 hour was significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Comparison of cold flush perfusion with modified blood versus modified Euro-Collins solution for lung preservation.

Single flush perfusion of the lung represents one concept of pulmonary preservation that has provided satisfactory results in both experimental and clinical situations. The technique has allowed successful distant organ procurement, with consequent enlargement of the available donor pool. Both cold modified blood (CMB) and modified Euro-Collins solution (ECS) are currently used as perfusates, although the volumes of each used clinically are different. CMB is administered at 20 ml/kg and ECS at 60 ml/kg. Both techniques combine the use of a prostaglandin to enhance preservation. In this study these two perfusion techniques were compared in a canine model of unilateral left lung allotransplantation after 6 hours of storage, with subsequent ligation of the recipient's contralateral pulmonary artery and bronchus. Equal volumes of both solutions were used (20 ml/kg) to determine whether the blood vehicle was necessary to provide good preservation at this volume. Assessment of pulmonary preservation was determined by animal survival, blood gas analyses, hemodynamic values, and measurement of lung water content. All animals survived the 24-hour experimental period in stable condition. Postoperative oxygenation was well maintained at control values throughout this period with no significant difference between groups. The pulmonary vascular resistance index was significantly higher in the CMB group at 1 hour (p less than 0.05). Lung compliance, assessed by peak-inspiratory pressure, was impaired to a greater extent in the CMB group than in the ECS animals (p less than 0.01 at 12 and 24 hours).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗