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Biomedical subjects

J S McLaughlin

Publications and source records attributed to J S McLaughlin.

At least 19 recordsLinked to original sources
PubMed2001

Experience with spiral computed tomography as the sole diagnostic method for traumatic aortic rupture.

BACKGROUND: Spiral computed tomographic (CT) scan is an excellent screen for aortic trauma. Traditionally, aortography is performed when injury is suspected to confirm the diagnosis. We hypothesized that it is safe and expeditious to forgo aortography when the spiral CT demonstrates aortic injury. METHODS: Retrospective review of 54 patients undergoing aortic repair from July 1994 to December 1999. Spiral CT was the initial diagnostic study in 52 patients. Pseudoaneurysm or aortic wall defect in the presence of mediastinal hematoma was considered diagnostic. Angiography, initially routine, was later performed only when requested by the surgeon, and for all "nonnegative" studies (periaortic hematoma without detectable aortic injury). RESULTS: Twenty-six patients underwent angiography before operation (group 1). Nineteen group 1 spiral CTs were unequivocally diagnostic; 7 were nonnegative and angiography was required. Twenty-eight other patients underwent repair based on spiral CT alone (group 2). There was one false-positive result in both groups. There were no unexpected operative findings. Mean time from admission to diagnosis was 5.7+/-3.4 hours for group 1 and 1.7+/-1.7 hours for group 2 (p < 0.01). CONCLUSIONS: Operating on the basis of a diagnostic spiral CT is safe and expeditious. Aortography may be reserved for those with equivocal studies.

Adolescent↗
PubMed2000

Heparinless partial cardiopulmonary bypass for the repair of aortic trauma.

OBJECTIVE: We hypothesized that partial cardiopulmonary bypass with a heparin-bonded system would be a technically simple, effective adjunct for reducing paraplegia during repair of traumatic aortic rupture. It avoids the risk of heparin, but, unlike left atrial-arterial bypass, it can heat, cool, oxygenate, and rapidly infuse volume if needed. METHODS: A retrospective review was conducted of patients admitted for aortic trauma from July 1994 to December 1999. Bypass consisted of femoral venous (right atrial) cannulation, a centrifugal pump, and an oxygenator-heater/cooler. Arterial return was to the femoral artery or distal aorta. The entire system was heparin-bonded and no systemic heparin was given. RESULTS: Heparin-bonded partial bypass was established in 50 patients (mean age 43 +/- 17 years). Crossclamp time was 32 +/- 11 minutes (range 14-70 minutes), mean flow 3.0 +/- 0.8 L/min, and bypass time 64 +/- 43 minutes. During repair, 58% of patients received volume through the system (mean 1.1 +/- 1.9 L). Core temperature rose slightly (35.9 degrees C +/- 0.7 degrees C to 36.3 degrees C +/- 0.8 degrees C). Three of the 15 patients who underwent percutaneous femoral arterial and venous cannulation concomitant with their angiograms had vessel injury, with one limb loss, and this procedure was discontinued. Thirty-five patients underwent percutaneous femoral vein and direct distal aortic cannulation without event. The mortality rate for patients supported by bypass was 10%, and all deaths were due to other injuries. There were no new cases of paraplegia and no worsening of intracranial or pulmonary injuries. CONCLUSIONS: Heparin-bonded bypass is technically simple to use and avoids the risk of anticoagulation. Paraplegia was avoided. The ability to correct hypothermia, oxygenate, and rapidly infuse volume may simplify management and improve outcomes.

Adult↗
PubMed1999

Traumatic aortic rupture: recent outcome with regard to neurologic deficit.

BACKGROUND: Traumatic aortic rupture is highly lethal, and its surgical treatment is complicated by a high rate of paraplegia. METHODS: The charts of 263 patients with traumatic aortic rupture from vehicular accidents treated between 1971 and 1998 were reviewed. Patients were grouped according to four periods: group 1, 1971 to 1975, (n = 31); group 2, 1976 to 1985, (n = 83); group 3, 1986 to 1994, (n = 82); and group 4, 1994 to 1998 (n = 67). Seventy-one patients died of exsanguination before definitive care. One hundred-ninety two patients had surgical repair with the following techniques: clamp and sew, 6 in group 1, 22 in group 2, 54 in group 3, none in group 4; shunt, 23 in group 1, 39 in group 2, 2 in group 3; cardiopulmonary bypass, 2 in group 1, 1 in group 3. Forty-three patients had partial bypass with the centrifugal pump and heparin-coated circuits in group 4. RESULTS: Operative mortality was 6 of 31 (19%) in group 1, 22 of 61 (36%) in group 2, 15 of 57 (26%) in group 3, and 7 of 43 (16%) in group 4. There was one case of paraplegia in group 1 (4%), ten in group 2 (18%), 11 in group 3 (26%), and none in group 4. This difference of paraplegia between the groups was significant (p<0.002). Significant factors for paraplegia were intraoperative hypotension (p<0.000002), cross-clamp time longer than 30 minutes (p<0.008), pump versus no pump (p<0.008), and younger age group (28+/-11 versus 39+/-17 years) (p<0.03). CONCLUSIONS: There were no statistically significant improvements in mortality rate over the four periods, although, the mortality rate was lowest in the last period when partial bypass with the centrifugal pump was used exclusively. Further, the use of the centrifugal pump with heparin-coated circuits, with femoral vein cannulation into the right atrium and distal aortic perfusion, reduced paraplegia significantly.

Accidents, Traffic↗
PubMed1999

Increased p53 protein expression in human failing myocardium.

BACKGROUND: The p53 gene is a tumor-suppressor gene which involves apoptosis and cell-cycle arrest under certain stress stimulate. However, the status of the p53 gene expression in human myocardium in congestive heart failure (CHF) remains unclear. Therefore, the current study was designed to investigate the expression of the p53 protein in human myocardium in normal subjects and in patients with severe CHF. METHODS: Human ventricular cardiac tissue was obtained from 7 normal subjects and 7 end-stage CHF patients during cardiac transplantation. The expression of p53 protein was determined by immunohistochemical staining. The cardiac apoptosis was determined by TUNEL staining. RESULTS: The p53 protein was minimally stained in normal human ventricular cardiomyocytes. In contrast, the staining density and positive stained nuclear (%) of p53 was significantly increased in ventricular cardiomyocytes of patients with severe CHF. Apoptosis in CHF human myocardium also markedly increased. CONCLUSIONS: The significantly increased expression of p53 in CHF human cardiomyocytes suggests that p53 may play an important pathophysiological role in the process of CHF through mechanisms involving myocardial apoptosis.

Adult↗
PubMed1998

Superior sulcus (Pancoast) tumor: experience with 105 patients.

BACKGROUND: The evolution of therapy in 105 patients with superior sulcus (Pancoast) tumor over the past 42 years was reviewed. METHODS: There were 82 men and 23 women aged 30 to 75 years. Tumor cell types were: squamous, 41 (39%); adenocarcinoma, 23 (21.9%); anaplastic, 14 (13.3%); undetermined, 12 (11.4%); mixed, 9 (8.7%); and large cell 6 (5.7%). Therapy was based on extent of disease and lymph node involvement. There were 5 treatment groups: I, preoperative radiation and operation (n = 28); II, operation and postoperative radiation (n = 16); III, radiation (n = 37); IV, preoperative chemotherapy, radiation, and operation (n = 11); and V, operation (n = 12). RESULTS: The median survival for group I was 21.6 months; group II, 6.9 months; group III, 6 months; and group V, 36.7 months. Median survival for group IV has not yet been reached (estimated at 72% at 5 years). On univariate analysis, mediastinal lymph node involvement, Horner syndrome, TNM classification, and method of therapy affected survival. On multivariate regression analysis, only N2 and N3 disease and method of therapy were significant (p < 0.05). CONCLUSIONS: The optimal treatment for superior sulcus tumor was preoperative radiation and operation. However, triple modality therapy, although promising, requires longer follow-up.

Adenocarcinoma↗
PubMed1996

Spatial and temporal variations in extracellular matrix of periocular and corneal regions during corneal stromal development.

The development of the avian corneal stroma occurs in discrete developmental stages. During this sequence of events, the neural crest-derived corneal fibroblast precursor cells are surrounded by distinct extracellular matrices which change both spatially and temporally. To elucidate the role of these matrices, extracellular matrix components in the periocular mesenchyme and cornea were analysed prior to and during migration and differentiation of corneal fibroblasts using antibodies against collagens, proteoglycans and glycoproteins. Previous work has concentrated on the matrix of the corneal stroma rather than the matrix of the periocular mesenchyme. Since the precursors of the corneal fibroblasts are present within the must migrate through the periocular mesenchyme prior to entry into the cornea proper, this environment was fully evaluated. The present study documents the matrix composition of both the cornea and periocular mesenchyme at developmental stages that are prior to and after initiation of corneal invasion by the corneal fibroblast precursors. Variations in matrix molecules comprising both the periocular mesenchyme and cornea were demonstrated. These include changes in the distribution of collagen types I, II, III, IV and VI; the proteoglycans decorin and lumican; as well as the adhesive glycoproteins tenascin, fibronectin and laminin. It is hypothesized that the variations in matrix localization are important in the regulation of cell migration and differentiation during normal corneal development. Any regulation is likely to involve a combination of components found in the extracellular matrices and therefore, a consideration of the matrix rather than isolated components is required.

Animals↗
PubMed1996

Complications of thoracoscopy.

BACKGROUND: The revolution in video technology has led to the acceptance of thoracoscopy as an important tool in thoracic surgery. METHODS: A review of all patients undergoing thoracoscopy at the University of Maryland between November 1991 and March 1995 was performed to identify the incidence of intraoperative and postoperative complications. In addition, the role of computed tomography for predicting intraoperative complications was analyzed. RESULTS: Three hundred forty-eight procedures were performed in 321 patients. Twenty-seven patients required conversion to thoracotomy for various indications. In 12 patients further resection was required after frozen section diagnosis confirmed lung carcinoma. Six patients were opened due to adhesions. Two patients were opened due to inability to find the lesion (this represents 1.6% of all solitary pulmonary nodules). Three cases were converted to thoracotomy for lesions that were too large to remove (representing 2.5% of all solitary pulmonary nodules resected). Two patients required conversion to thoracotomy because of inability to obtain one-lung ventilation. One case required a limited thoracotomy for a lost needle used for needle localization of a solitary intraparenchymal nodule, and 1 patient had emergent exploration for bleeding. Early postoperative complications developed in 10 patients. There were two explorations in the immediate postoperative period for bleeding. Prolonged air leak occurred in 3 patients, empyema in 2, and recurrent pneumothorax, pulmonary edema, and pneumonia in 1 patient each. Computed tomography failed to diagnose adhesions in the majority of patients requiring conversion to thoracotomy. CONCLUSIONS: Thoracoscopy is a safe and effective procedure with low intraoperative and postoperative complication rates.

Baltimore↗
PubMed1996

Open drainage of massive tuberculous empyema with progressive reexpansion of the lung: an old concept revisited.

BACKGROUND: This study examined the results of open drainage of massive tuberculous empyema. METHODS: During a 7-year period 47 patients with primary mixed chronic tuberculous empyema with near or total lung collapse were treated. The initial procedure was chest tube suction drainage, which permitted evaluation of the pleural cavity and the lung parenchyma despite minimal if any reexpansion of the lung. All patients were treated with antibiotics and multidrug regimens of antituberculosis agents. A pleurocutaneous window was established by removing sections of two ribs one intercostal space above the base of the pleural cavity. Irrigation was performed daily with dilute povidone iodine solution. RESULTS: Twenty-eight patients achieved complete reexpansion of the lung after 4 to 30 months of drainage and are cured. Eleven are in various stages of reexpansion and probably will be cured. Eight patients did not achieve reexpansion. Criteria were established retrospectively on an ongoing basis that indicate when pulmonary reexpansion is possible. CONCLUSIONS: These totally collapsed "entrapped" lungs expanded to fill the entire pleural space despite the presence of bronchopleural fistulas and an "open" pleura. Reexpansion was progressive, gradual, and dependent on improved compliance, clearing of bronchial inflammation and obstruction, and pleural cleansing. Criteria are established that identify those patients in whom complete reexpansion may take place and the disease may be cured.

Adolescent↗
PubMed1996

Nitric oxide mediates fluid accumulation during cardiopulmonary bypass.

Fluid accumulation during cardiopulmonary bypass may be related to the production of endogenous vasoactive substances. We investigated the role of nitric oxide in mediating fluid accumulation during cardiopulmonary bypass. Normothermic cardiopulmonary bypass was carried out for 3 hours in male Sprague-Dawley rats with constant, nonpulsatile flow and hemodilution. Fluid accumulation (rate of change of external reservoir volume) was measured under three experimental conditions: saline solution control (n = 8), L-arginine infusion (n = 6), and N-nitro-L-arginine methyl ester infusion (n = 6). At the end of the experiments, body weight and organ wet/dry ratios were examined. Percentage weight gain was 77% greater in the N-nitro-L-arginine methyl ester group and 23% less in the L-arginine group compared with control values. Fluid accumulation was increased with N-nitro-L-arginine methyl ester after 30 minutes (p < 0.01) and reduced with L-arginine after 120 minutes (p < 0.01) compared with control animals. Water content was significantly decreased in the heart, lung, skin, muscle and peritoneum in rats receiving L-arginine. These data suggest that endogenous nitric oxide plays an important role in minimizing fluid accumulation during cardiopulmonary bypass.

Animals↗
PubMed1995

The role of thoracoscopy in the diagnosis of interstitial lung disease.

A study was undertaken to evaluate the safety and efficacy of thoracoscopic lung biopsy for interstitial lung disease. The relation between operative findings, pathologic findings, and preoperative computed tomographic scan findings was examined. Twenty-six patients, 10 male and 16 female, underwent thoracoscopic lung resection to diagnose interstitial lung disease. Sixteen patients were outpatients for an elective procedure; 10 were inpatients including 2 who were ventilator dependent. The mean length of operation was 54 minutes and the mean length of chest tube duration, 1.3 days. There were no deaths. Staphylococcal pneumonia developed in 1 patient postoperatively. One patient with systemic pulmonary hypertension was ventilator dependent for 48 hours. A double-lumen endotracheal tube was used in all but 2 patients. Twelve-millimeter trocar ports were used to allow easy interchange of staplers and endoscopic instruments. Biopsy of at least two lobes was performed in each patient with resection of a piece of grossly abnormal lung. A single chest tube was left routinely. The pathologic diagnosis was usual interstitial pneumonitis in 7 patients. Four patients had interstitial fibrosis and 4, granulomas. Three patients had diffuse alveolar damage and 3, Wegener's granulomatosis. Two patients had bronchiolitis obliterans with organizing pneumonia. One patient each had lymphangioleiomyomatosis, eosinophilic granuloma, and cytomegalovirus. Sixteen patients underwent preoperative computed tomographic scanning. The scans were assessed by 2 radiologists who were blinded to the surgical results. Computed tomography accurately predicted the site of disease in most instances. Four patients had at least one lobe with no evidence of disease on computed tomography but with interstitial lung disease found thoracoscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1995

Acute hemodynamic effects of atrio-biventricular pacing in humans.

Standard postoperative dual-chamber pacing uses ventricular leads placed on the right ventricle that produce dysynchronous ventricular activation and contraction. The hypothesis that simultaneous stimulation of both ventricles by atrio-biventricular pacing improves hemodynamic performance compared with that observed with standard atrio-monoventricular pacing was tested in 18 patients 12 to 36 hours after elective coronary artery revascularization. Temporary epicardial pacing electrodes were placed on the right atrium and into anterior paraseptal sites on the right and left ventricle. Simultaneous biventricular activation was documented by fusion morphology of surface electrocardiograms and by isochronal epicardial activation mapping during biventricular pacing. Hemodynamic data were acquired after 10 minutes of pacing at a fixed overdrive rate during atrial pacing and during dual-chamber pacing using unipolar right ventricular, unipolar left ventricular, and bipolar biventricular (left ventricular cathode) leads. Atrio-biventricular pacing increased cardiac index and decreased systemic vascular resistance compared with atrial pacing and with atrio-right ventricular and atrio-left ventricular dual-chamber pacing (p < 0.05). These data support the use of atrio-biventricular pacing employing paraseptal electrodes to optimize hemodynamic performance.

Adult↗
PubMed1995

Subarachnoid-pleural fistula after resection of a pancoast tumor with hyponatremia.

Resection of superior sulcus neoplasms is associated with a number of complications resulting from the extensive nature of the resection and the necessity to sacrifice certain adjacent structures. One of the complications of resection is the development of subarachnoid-pleural fistula, with the subsequent appearance of air in the cerebrospinal fluid circulation. We report a case in which a subarachnoid-pleural fistula led to persistent pneumocephaly in a patient who exhibited postoperative hyponatremia, confusion, and gait disturbance.

Aged↗
PubMed1995

Paraplegia after thoracotomy: report of five cases and review of the literature.

Paraplegia complicating thoracotomy is rare but catastrophic. This report comprises 40 cases: 5 of our cases and 35 reported cases. Our cases comprised a stab wound of the left chest (1), decortication (1), lobectomy for bronchogenic carcinoma (2), and segmental resection for tuberculosis (1). The reported cases included 25 cases following thoracotomy for thoracic pathology (bronchogenic carcinoma, 12; pulmonary tuberculosis, 7; thoracic trauma, 2; bronchiectasis, 1; peptic esophagitis, 1; neurogenic tumors, 2; and benign lung lesion, 1 and 10 cases following operation for malignant hypertension. The surgical procedures performed on the 25 patients with thoracic pathology were lobectomy (8), bilobectomy (1), pneumonectomy (7), decortication (1), thoracoplasty (1), excision of neurogenic tumors (2), drainage of tuberculous cavity (1), and Nissen procedure (1). The intraoperative factors contributing to the neurologic deficit were bleeding at the costovertebral angle (9), migration of oxidized cellulose into spinal canal (9), thrombosis of anterior spinal artery (4), epidural hematoma (2), epidural narcotic (2), metastatic carcinoma (1), and hypotension (1). This serious complication can be prevented by meticulous operation and careful hemostasis. The immediate use of tomographic scanning or magnetic resonance imaging followed by surgical decompression might avert this serious complication.

Adult↗
PubMed1994

Extravascular fluid uptake during cardiopulmonary bypass in hypertensive dogs.

We investigated the effects of increases in central venous pressure (CVP) and carotid baroreceptor-induced vasodilation on the rate of extravascular fluid uptake during cardiopulmonary bypass in normotensive and Goldblatt hypertensive dogs. Carotid sinus baroreceptors were selectively perfused to control the level of vasodilation. Central venous pressure was controlled by changing the height of the venous outflow cannula. Extravascular fluid uptake was determined from the rate of change in reservoir volume. After 3 hours of bypass, total fluid accumulation was 56.11 +/- 14.16 mL/kg in normotensive dogs, significantly less than in hypertensive dogs (110.90 +/- 23.20 mL/kg) (p < 0.05). Raising CVP from 1 to 5 mm Hg increased the rate of extravascular fluid uptake in both normotensive (from 0.05 +/- 0.25 to 0.85 +/- 0.22 mL.kg-1.min-1; p < 0.05) and hypertensive dogs (from 0.68 +/- 0.28 to 2.57 +/- 0.46 mL.kg-1.min-1; p < 0.01)). At a constant CVP, baroreceptor-induced vasodilation increased the rate of extravascular fluid uptake in normotensive (from 0.25 +/- .15 to 0.81 +/- .22 mL.kg-1.min-1) and in hypertensive dogs (from 0.84 +/- .12 to 1.72 +/- .32 mL.kg-1.min-1; p < 0.05). Hypertensive dogs were more sensitive to changes in CVP and to baroreceptor-induced vasodilation. The results of this study imply that elevations in CVP or the use of vasodilators may lead to increased extravascular fluid uptake during bypass; this effect may be exacerbated in the hypertensive state.

Animals↗