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Biomedical subjects

G A Patterson

Publications and source records attributed to G A Patterson.

At least 253 records · Page 14Linked to original sources
PubMed1987

Peptic ulcer in acquired columnar-lined esophagus: results of surgical treatment.

Ulcerative peptic esophagitis may lead to the progressive replacement of squamous by columnar epithelium in the distal esophagus. A typical peptic ulcer (Barrett's ulcer) may develop in the columnar-lined segment, although this is a rare occurrence. Between 1975 and 1985 at Toronto General Hospital we treated 11 patients with penetrating peptic ulcer and acquired, columnar-lined esophagus. Presenting symptoms related to the ulcer were precordial and lower dorsal back pain in 4 patients, dysphagia in 6, and massive hemorrhage of the upper gastrointestinal tract in 4. None of the ulcers healed following a trial of medical therapy, and ultimately all 11 patients underwent antireflux procedures (gastroplasty and partial fundoplication). There was one operative death. Complete healing of the ulcer was observed in the 8 patients who underwent follow-up endoscopy between two and five months after operation. There has been no recurrence of symptoms resulting from ulcer in subsequent follow-up, which extends from 1 to 11 years (mean, 5 years). Adenocarcinoma developed in the columnar-lined segment in 2 of the 11 patients, which was diagnosed at 32 and 91 months following operation, respectively.

Adult↗
PubMed1987

Medial antebrachial cutaneous--lateral femoral cutaneous neurotization in restoration of sensation to pressure-bearing areas in a paraplegic: a four-year follow-up.

Loss of cutaneous sensation predisposes paraplegics to ulceration in pressure-bearing areas. We have previously described a method of restoring sensation to anesthetic trochanteric or ischial areas by neurotizing the cutaneous territory of the lateral femoral cutaneous nerve with the medial antebrachial cutaneous nerve of the forearm. After reinnervation of the anterior skin, a musculocutaneous flap is rotated to the desired anesthetic area. A four-year follow-up evaluation has shown good recovery of the quickly and slowly adapting fiber receptor system, mediated through innervated hair follicles and resulting in excellent protective sensation.

Adult↗
PubMed1987

Gastroplasty and fundoplication for complex reflux problems. Long-term results.

Between 1964 and 1984, 430 patients with complex reflux problems were managed by a modified Collis gastroplasty and partial fundoplication. The indications for selecting the addition of gastroplasty were as follows: (1) obvious acquired shortening due to peptic esophagitis and stricture, and (2) subtler degrees of acquired shortening frequently encountered in cases that required reoperation and in patients with massive sliding hiatal hernia. The addition of gastroplasty in this second group obviates the risk of even minimal tension on the repair. Follow-up is complete in 382 patients (90%), and extends 1-20 years. Two hundred fifty patients have been followed up for 5 or more years and 101 patients for more than 10 years. Results were classified as follows: good: asymptomatic, or inconsequential symptoms requiring no therapy; fair: improved, but with symptoms and/or endoscopic findings requiring intermittent therapy; poor: unimproved or worse. Patients are divided into four categories, and the results are tabulated below (see Table 2). The best results are obtained in patients with acquired shortening due to esophagitis with and without stricture who have had no prior antireflux surgery and have no associated primary motor disorder. The proportion of unsatisfactory results is almost tripled (20% fair or poor) after reoperation after one or more failed antireflux procedures. When reflux esophagitis and stricture are associated with a primary motor disorder, only half of the patients have a good result sustained throughout long-term follow-up.

Adenocarcinoma↗
PubMed1987

Technique of successful lung transplantation in humans.

We have performed five single lung transplantations for end-stage pulmonary fibrosis, with four long-term survivors. Two patients underwent right lung transplantation and two underwent left lung transplantation. The procedure is performed with one lung anesthesia, although cardiopulmonary bypass is available on standby if required. Donor and recipient procedures are performed in adjacent operating rooms. On the basis of laboratory studies, a pedicle of omentum is wrapped around the bronchial anastomosis after its completion to restore bronchial artery circulation and protect the anastomosis. The four patients were discharge from the hospital within 4 to 6 weeks and three returned to normal employment at 3 months. Success in these cases is attributed to careful patient selection, use of cyclosporine, and use of an omental pedicle to protect and improve healing of the bronchial anastomosis.

Cyclosporins↗
PubMed1987

A prospective evaluation of magnetic resonance imaging, computed tomography, and mediastinoscopy in the preoperative assessment of mediastinal node status in bronchogenic carcinoma.

Computed tomography, magnetic resonance imaging, chest roentgenography, and mediastinoscopy were compared prospectively as staging modalities to assess mediastinal node status in 84 patients with presumed operable bronchogenic carcinoma. Computed tomography was associated with a sensitivity of 71.0%, a specificity of 87.7% and an overall accuracy of 82.1%. Magnetic resonance imaging did not provide any advantage over computed tomography in the assessment of mediastinal node status. The accuracy of computed tomography was not dependent on cell type of the primary tumor. Although chest roentgenography had a sensitivity of 80.7%, the overall accuracy of 57.1% was unacceptably low. The sensitivity (87.1%), specificity (100%), positive (100%) and negative (93.0%) predictive values, and accuracy (95.2%) of mediastinoscopy exceeded those observed with all other modalities. We continue to recommend mediastinoscopy as the most accurate staging investigation in the routine management of patients with bronchogenic carcinoma.

Carcinoma, Bronchogenic↗
PubMed1986

Experimental en bloc double-lung transplantation.

A technique of en bloc double-lung transplantation through a median sternotomy has been developed. Hypothermic circulatory arrest was used after surface cooling in 7 puppies (mean weight, 3.1 kg; range, 1.5 to 4.1 kg). A double lung block, consisting of the two lungs, distal trachea, the main pulmonary artery, and a large cuff of left atrium, was removed from weight-matched donors. After the arrest of the circulation by inflow occlusion, bilateral pneumonectomies were performed in the recipient. The donor double-lung block was then implanted with anastomoses at the distal trachea, the posterior left atrium, and the main pulmonary artery. All animals were successfully rewarmed and had excellent hemodynamic function and gas exchange for periods of up to 24 hours. If primate experiments with long-term survival confirm these initial results, this procedure may have a role in the treatment of patients with end-stage respiratory disease but acceptable cardiac function.

Animals↗
PubMed1986

Precision cautery excision of pulmonary lesions.

We have used a cautery dissection technique, initially described by Perelman, to facilitate nonanatomical pulmonary resections in certain instances in which the anatomical location of the lesion made wedge excision by standard methods difficult or impossible. With the precision cautery technique, the raw surface of the lung is left charred and allows minimum or no air leakage following the procedure. We have found this method a useful addition to existing techniques for pulmonary resection.

Electrocoagulation↗
PubMed1986

Effect on cardiopulmonary changes of gram-negative endotoxemia in sheep after type-specific, cross-reactive, and nonspecific immune stimulation.

The purpose of this study was to examine the effects of prior nonspecific immune stimulation (BCG), cross-reactive immunization (E coli J5 0111 whole cells [J5 WC], and core glycolipid [J5 CGL]), and type-specific immunization (Serratia marcescens core glycolipid [SM CGL]) on the cardiopulmonary variables and white blood cell counts of awake, monitored sheep following IV Serratia marcescens endotoxin. Comparison of cardiac output, pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance, alveolar-arterial oxygen gradients, and total white blood cells lead us to conclude that type-specific immunization (SM CGL) most effectively ameliorates the changes of gram-negative endotoxemia contrasted to nonimmunization. Core glycolipid cross-reactive (J5 CGL) immunization was somewhat more effective than whole-cell cross-reactive (J5 WC) immunization in this regard. Nonspecific immune stimulation (BCG) was able only to significantly decrease the changes in pulmonary vascular resistance compared to nonimmunization.

Animals↗
PubMed1986

Prospective evaluation of mediastinoscopy for assessment of carcinoma of the lung.

Between 1979 and 1984, mediastinoscopy was performed on 1,000 of the 1,500 patients admitted to the Thoracic Surgical Service of the Toronto General Hospital with the diagnosis of carcinoma of the lung. In 144 cases, concomitant anterior mediastinoscopy was also performed. Abnormal mediastinal nodes were found in 296 (29.6%). The overall complication rate was 2.3%, with no deaths. Mediastinoscopy revealed diseased nodes in 24% of patients with squamous cell carcinoma, 29% with adenocarcinoma, 54% with small cell undifferentiated carcinoma, 31% with large cell undifferentiated carcinoma, and 12% with bronchoalveolar carcinoma. Abnormal mediastinal nodes were found with equal frequency in right- and left-sided tumors and occurred in 31% of tumors in the main bronchus, 25% of upper lobe tumors, and 17% of lower lobe tumors. Of the 704 patients having negative results of mediastinoscopy, 590 were subjected to thoracotomy. Ninety-three percent underwent resection (85% curative, 7% palliative) and 7% had unresectable tumors. Of the resections, 20% were pneumonectomies. At thoracotomy, 52 of the 590 patients with negative mediastinoscopic results were found to have abnormal mediastinal nodes. Sixty-two of the 296 patients with positive results of mediastinoscopy were selected for thoracotomy. Eighty-six percent had resectable lesions (67% curative, 18% palliative) and 14% unresectable. The pneumonectomy rate in this group was 35%. These current data support our previous opinion that routine mediastinoscopy can be done with negligible morbidity and provides essential information for the classification and management of cancer of the lung.

Adenocarcinoma↗
PubMed1985

Medial antebrachial cutaneous-lateral femoral cutaneous neurotization to provide sensation to pressure-bearing areas in the paraplegic patient.

Although rotation of musculocutaneous flaps can achieve closure of pressure sores, these insensitive flaps in the paraplegic or quadriplegic contribute to recurrent ulceration. This report suggests a method of reinnervating the territory of the lateral femoral cutaneous nerve (the tensor fascia lata musculocutaneous flap) using the medial antebrachial cutaneous nerve of the forearm. This neurotization procedure has restored sensibility to the area of the healed pressure sore.

Adult↗
PubMed1985

Assessment of fluid balance in isolated sheep lungs.

In this study we demonstrate the validity and utility of an isolated lung preparation developed for the study of pulmonary fluid balance. Lungs of 2- to 3-mo-old sheep were perfused in situ with autologous blood treated with indomethacin (20 micrograms/ml). Lung lymph flow (QL), uncontaminated by systemic lymph, was measured from either the efferent duct of the caudomediastinal lymph node or the thoracic duct in the superior mediastinum. Lung weight change (delta W) was measured as the opposite of the change in weight of the extracorporeal blood reservoir. A unique feature of this experimental model is the ability to assess lung fluid balance from simultaneous measurements of delta W and QL. In addition, hemodynamic and blood gas variables can be tightly controlled. Our results show that changes in QL and the lymph-to-plasma oncotic pressure ratio caused by an increase in microvascular pressure were comparable with those seen previously in intact sheep. When microvascular pressure was returned to control levels, QL fell despite a sustained increase in the amount of extravascular lung water, suggesting compartmentalization of the filtrate and/or effects of intravascular volume on lymph-driving pressure or resistance. Lymph flow was directly proportional to respiratory frequency over the range of 0-30 min-1 when the change in frequency was maintained for periods as long as 30 min. This preparation should prove useful in the study of lung fluid balance, particularly when it is desired to use interventions which are precluded or difficult in intact animals.

Animals↗
PubMed1985

Effects of imidazole and indomethacin on fluid balance in isolated sheep lungs.

We determined the effects of extracorporeal perfusion with a constant flow (75 ml . min-1 . kg-1) of autologous blood on hemodynamics and fluid balance in sheep lungs isolated in situ. After 5 min, perfusate leukocyte and platelet counts fell by two-thirds. Pulmonary arterial pressure (Ppa) increased to a maximum of 32.0 +/- 3.4 Torr at 30 min and thereafter fell. Lung lymph flow (QL), measured from the superior thoracic duct, and perfusate thromboxane B2 (TXB2) concentrations followed similar time courses but lagged behind Ppa, reaching maxima of 4.1 +/- 1.2 ml/h and 2.22 +/- 0.02 ng/ml at 60 min. Lung weight gain, measured as the opposite of the weight change of the extracorporeal reservoir, and perfusate 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) concentration increased rapidly during the first 60 min and then more gradually. After 210 min, weight gain was 224 +/- 40 g and 6-keto-PGF1 alpha concentration, 4.99 +/- 0.01 ng/ml. The ratio of lymph to plasma oncotic pressure (pi L/pi P) at 30 min was 0.61 +/- 0.06 and did not change significantly. Imidazole (5 mM) reduced the changes in TXB2, Ppa, QL, and weight and platelet count but did not alter 6-keto-PGF1 alpha, pi L/pi P, or leukocyte count. Indomethacin (0.056 mM) reduced TXB2, 6-keto-PGF1 alpha, and the early increases in weight, Ppa, and QL but did not alter the time courses of leukocyte or platelet counts. Late in perfusion, however, Ppa and QL were greater than in either untreated or imidazole-treated lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Nature and distribution of vascular resistance in hypoxic pig lungs.

We used the vascular occlusion technique in pig lungs isolated in situ to describe the effects of hypoxia on the distribution of vascular resistance and to determine whether the resistive elements defined by this technique behaved as ohmic or Starling resistors during changes in flow at constant outflow pressure, changes in outflow pressure at constant flow, and reversal of flow. During normoxia, the largest pressure gradient occurred across the middle compliant region of the vasculature (delta Pm). The major effect of hypoxia was to increase delta Pm and the gradient across the relatively noncompliant arterial region (delta Pa). The gradient across the noncompliant venous region (delta Pv) changed only slightly, if at all. Both delta Pa and delta Pv increased with flow but delta Pm decreased. The pressure at the arterial end of the middle region was independent of flow and, when outflow pressure was increased, did not increase until the outflow pressure of the middle region exceeded 8.9 Torr during normoxia and 18.8 Torr during hypoxia. Backward perfusion increased the total pressure gradient across the lung, mainly because of an increase in delta Pm. These results can be explained by a model in which the arterial and venous regions are represented by ohmic resistors and the middle region is represented by a Starling resistor in series and proximal to an ohmic resistor. In terms of this model, hypoxia exerted its major effects by increasing the critical pressure provided by the Starling resistor of the middle region and the ohmic resistance of the arterial region.

Analysis of Variance↗
PubMed1985

Radiotherapy alone for patients with operable carcinoma of the lung.

Between 1966 and 1980, 72 patients with operable carcinoma of the lung were treated primarily with radiotherapy because coexisting, nontumor related medical problem, or patient refusal prevented thoracotomy. We compared results obtained in this group with results obtained by thoracotomy in 123 consecutive patients over the age of 70, who were assessed in a similar fashion, but who underwent thoracotomy. All patients in both groups had proven, nonsmall cell carcinoma of the lung without clinical, laboratory, or radiologic evidence of tumor spread. All patients in both groups had a negative staging mediastinoscopy, and bronchoscopic findings consistent with operability. Many of the patients treated with radiotherapy had less than a curative dose as their general medical condition prevented a course of radical radiotherapy. It is apparent, however, that the results of radiotherapy for patients with operable carcinoma of the lung may be disappointing and that for patients who are marginal in terms of operative risk, the benefits of surgical resection may warrant the risks involved.

Actuarial Analysis↗
PubMed1982

The value of adjuvant radiotherapy in pulmonary and chest wall resection for bronchogenic carcinoma.

Thirty-five patients, 29 men and 6 women, underwent pulmonary and chest wall resection for treatment of bronchogenic cancer which had extended into the chest wall. Anterior chest wall resection was performed in 6 patients, lateral resection in 2, and posterior resection in 27. Marlex mesh was employed as a prosthetic material in 13 patients. Radiotherapy was given as part of the planned therapeutic regimen in 13 patients. Three patients (8.5%) died in the postoperative period. There was 21 late deaths. Eleven patients are alive 7 months to 12 years after resection. The overall actuarial survival, including operative mortality, is 38% at 5 years. Actuarial survival of the 13 irradiated patients is 56% at 2 and 5 years. We believe that bronchogenic carcinoma with chest wall involvement is not hopeless, and that resection of the lung and chest wall can be performed with an acceptable mortality rate.

Aged↗