Peter P. McKeown

Neural Transplantation as an Experimental Treatment Modality for Cerebral Ischemia

Cerebrovascular disease exemplifies the poor regenerative capacity of the CNS. While there are methods to prevent cerebral infarction, there is no effective therapy available to ameliorate the anatomical, neurochemical and behavioral deficits which follow cerebral ischemia. Focal and transient occlusion of the middle cerebral artery (MCA) in rodents has been reported to result in neuropathology similar to that seen in clinical cerebral ischemia. Using specific techniques, this MCA occlusion can result in a well-localized infarct of the striatum. This review article will provide data accumulated from animal studies using the MCA occlusion technique in rodents to examine whether neural transplantation can ameliorate behavioral and morphological deficits associated with cerebral infarction. Recent advances in neural transplantation as a treatment modality for neurodegenerative disorders such as Parkinsons disease, have revealed that fetal tissue transplantation may produce neurobehavioral recovery. Accordingly, fetal tissue transplantation may provide a potential therapy for cerebral infarction. Preliminary findings in rodents subjected to unilateral MCA occlusion, and subsequently transplanted with fetal striatal tissue into the infarcted striatum have produced encouraging results. Transplanted fetal tissue, assessed immunohistochemically, has been demonstrated to survive and integrate with the host tissue, and, more importantly, ameliorate the ischemia-related behavioral deficits, at least in the short term. Although, this review will focus primarily on cerebral ischemia, characterized by a localized CNS lesion within the striatum, it is envisioned that this baseline data may be extrapolated and applied to cerebral infarction in other brain areas.

Squamous cell carcinoma of the lung: An unusual metastasis to pectoralis muscle

A 44-year-old man with clinical T2 N0 M0 squamous cell carcinoma of the lung presented 4 weeks after left pneumonectomy with a single metastasis to his right pectoralis major muscle. Three years after excision and chemotherapy he remains in remission. Muscle metastasis of carcinoma is an infrequent occurrence. Further investigation into the incidence and treatment is warranted.

Thoracoscopic lung biopsy

Progress in instrumentation and techniques developed for laparoscopic surgery have paved the way for a resurgent interest in thoracoscopic procedures. Traditional thoracoscopy was limited by access, restricted visualization, and surgical devices. Recent cases provided an opportunity to successfully perform thoracoscopic pulmonary wedge excisions using state-of-the-art technology and instruments adapted from laparoscopy. These preliminary cases provided an opportunity to modify and adapt these techniques to thoracic procedures. Video thoracoscopy is rapidly evolving in both methods and instrumentation.

Blunt traumatic rupture of pulmonary vein, left atrium, and bronchus

A 22-year-old man fell 12.2 m (40 ft), injuring the right lower lobe bronchus, right inferior pulmonary vein, and left atrium. These injuries were not associated with fractures, cardiac tamponade, or pneumothorax. The severity of injury became apparent only upon right thoracotomy for persistent hemorrhage. This case presented special diagnostic and surgical challenges and suggests a role for the increased use of bronchoscopy in major blunt chest trauma.

Resection of Left Ventricular Tumor Using Videocardioscopy and Echocardiography

Assessment of large cardiac tumors requires careful definition of the extent, cell type, and degree of invasiveness to determine the best operative management. Preoperative magnetic resonance imaging and echocardiography were helpful, but limited in the assessment and management in the case of a 19-year-old pregnant woman with a large (9 x 5.5-cm) left ventricular mass. Intraoperative echocardiography and videocardioscopy facilitated precise operative decisions and management. Successful resection was achieved without the need for cardiac transplantation. This case demonstrates the complexity of the diagnosis and management of large cardiac tumors.

Legionella pericarditis diagnosed by direct fluorescent antibody staining

Legionella pericarditis is a rare and serious manifestation of Legionnaires disease. A case is presented in which the diagnosis was established by direct fluorescent antibody staining on a pericardial tissue specimen. Video-assisted thoracoscopy was used safely and effectively in diagnosis and management in this case.

A Magnetically Actuated Left Ventricular Assist Device

Over the past 6 years, research has led to development of a small, lightweight, power-efficient, uniquely simple ventricular assist device driven by a magnetic actuator. Magnetic actuation permits total elimination of all mechanical motion converter components used for pusher plate displacement, resulting in a significant reduction in complexity and resultant increase in reliability. Extensive in vitro mock loop development has resulted in a left ventricular assist device (LVAD), the primary design parameters of which for the clinical prototype actuator and pump are 1) an actuator weight of 312 g, 2) actuator size of 32.5 cm3, 3) power requirements of 7.8 to 11.4 watts (60-100 beats per minute [BPM]), and 4) system efficiency of 24% to 34% and average dynamic stroke volume of 65 ml. Initial in vivo tests assessed this LVADs performance in four sheep under three acute conditions of ventricular dysfunction. The results demonstrate that, at a pump-rate of 100 BPM, mean aortic pressure increased by 45-50 mmHg during 1) beta blockade, 2) coronary ligation, and 3) ventricular fibrillation. Pump flow ranged from 2.71 L/min to a maximum of 4.6 L/min. Acute test periods were arbitrarily set for 6 hours duration. Of the four sheep, two survived, one lived 5 hours, and the fourth lived 4.5 hours. Global fibrillation was the primary cause of failure. This initial in vivo data demonstrates the pumps ability to maintain satisfactory hemodynamic parameters of flow and pressure under three acute conditions of extreme left ventricular dysfunction in an animal model. These initial LVAD performances were encouraging. Further tests will use calves with a greatly expanded performance evaluation protocol.

Gastric pseudolymphoma : not necessarily a benign lesion

SummaryGastric pseudolymphoma is thought to be a benign process. This report documents the malignant behavior of a gastric pseudolymphoma that was thought to be benign until a distant malignant B-cell lymphoma was demonstrated. Subsequent evaluation traced the B-cell lymphoma back to the gastric “pseudolymphoma.” This finding stresses the relationship between gastric pseudolymphoma and gastric lymphoma, and the malignant potential of gastric pseudolymphoma. Multimodal tissue evaluation using histology, immunohistochemistry, and flow cytometry is essential. Surgical resection is the primary therapy for gastric pseudolymphoma.

Cardiopulmonary bypass for a coronary artery bypass graft patient with heterozygous protein C deficiency and protein S deficiency

Cardiopulmonary bypass (CPB) poses great risks for hypercoagulable patients and requires management techniques to ensure an optimal outcome free from thrombotic events. This case report reviews perfusion management techniques that may contribute to a safer CPB experience for a patient deficient in both protein C and protein S. A patient with heterozygous protein C deficiency is at increased risk of thrombosis, especially in the venous circulation. Since it is an essential cofactor for activated protein C, deficiency of free protein S is also linked to a hypercoagulable condition. A 52-year-old male presented to our institution with a past medical history of hypercoagulable state, multiple deep vein thromboses, pulmonary embolisms, and stroke. He was scheduled for two-vessel coronary artery bypass graft surgery to be followed by right carotid endarterectomy (RCEA) before discharge. The anesthesia and perfusion teams worked closely together to ensure that fresh frozen plasma (FFP) was given intraoperatively at appropriate times. Heparin dose response and protamine dosage was determined with hemostasis management system (HMS) analysis. The closed CPB circuit and cannulae were Carmeda bonded. Rapid autologous priming, along with the use of a hemoconcentrator, kept the hematocrit above 21 during CPB. Zero-balance ultrafiltration and leukocyte depletion were initiated during rewarming to aid in attenuation of the inflammatory response. To conserve coagulation factors, all pump blood was ultrafiltrated post-CPB and returned to the patient. Laboratory samples drawn on postoperative day (POD) one measured normal protein C activity with subnormal protein S activity. On POD six, the patient underwent RCEA and he was discharged on POD eight without complications.

Clinical anatomy instruction in the operating room

Instruction in regional gross anatomy is facilitated by a series of illustrations projected in the operating room and viewed sequentially during major operations. This teaching method is described, and the evaluations by the medical students confirm the efficacy of the method.