Complications resulting from saphenous vein patch graft after carotid endarterectomy

OBJECTIVE: Reducing surgical risks to the minimum in carotid endarterectomy has become crucial, especially with the results of recent clinical trials extending indications to asymptomatic patients. The use of the saphenous vein patch graft (SVPG) has been suggested to reduce early postoperative thrombosis and cerebral infarct as well as late recurrent stenosis. However, the exact risks and complications involved in this technique are not known. METHODS: During a 23-year period (1972-1994), 2888 carotid endarterectomies with SVPG for primary carotid stenosis were performed by the Neurosurgical Cerebrovascular Service at the Mayo Clinic. The data from all patients were retrospectively analyzed, emphasizing postoperative complications related to SVPG. RESULTS: There were five postoperative vein ruptures (0.17%), four cases of aneurysm formation, and three cases of deep infection necessitating surgical intervention. The vein patch ruptured in one male patient and four female patients (mean age, 69 yr). All ruptures occurred within 4 days of the primary operation, including two during the first 24 hours. All patients with rupture underwent emergency surgery and were found to have intact suture lines and tears in the middle of the grafts. Two patients recovered without deficits, one suffered major disability, and the other two died. Aneurysm of the patch developed in two male patients and two female patients (mean age, 71 yr). All of the patients developed painless pulsatile neck masses 1 to 9 years after the initial surgery; two also had recurrent ischemic symptoms. All of the patients with aneurysms underwent surgical correction without consequences. CONCLUSION: Although the benefit of routine use of SVPG in carotid endarterectomy is still the focus of debate, this analysis showed that its use adds a small but definite risk of serious complications related to inherent weakness of the venous tissue. If a surgeon chooses to use a patch graft, our recommendation is for use of a synthetic material rather than vein.     

Platelet and neutrophil distributions in pump oxygenator circuits. III. Influence of nitric oxide gas infusion

The authors used quantitative gamma scintigraphy to evaluate the influence of nitric oxide gas on platelet and neutrophil deposition in Cobe Duo microporous oxygenators during cardiopulmonary bypass (CPB). The effects of nitric oxide gas on circulating platelet and neutrophil counts and platelet function also were assessed. Animals were prepared by standard methods. Cells were harvested, labeled (111 In platelet and 99mTc neutrophil), infused, and recirculated. Nitric oxide gas, a guanylate cyclase pathway promoter, was infused int he Duo gas port at 500 ppm (t = 0-60 min), increased to 1,000 (t = 60-80 min), and stopped (final, 10 min). Images were taken at 10-15 min intervals during CPB. Standard isotope image corrections were made. No differences between nitric oxide gas and control experiments were observed for flow, pressure, hematocrit, or replacement volume. Nitric oxide gas infusion significantly (p < 0.05) reduced both platelet adherence to the oxygenator and in vitro platelet aggregation. Neutrophil adhesion tended to be lower, and circulating platelet and neutrophil counts tended to be higher with nitric oxide gas infusion. Results of in vitro aggregometry studies using rabbit platelets indicate that the class V phosphodiesterase inhibitor zaprinast can strongly enhance the inhibitory effects of nitric oxide. The authors conclude nitric oxide gas is a promising platelet sparing agent in the setting of CPB.     

Nicotinamide-adenine dinucleotide phosphate oxidase assembly and activation in EBV-transformed B lymphoblastoid cell lines of normal and chronic granulomatous disease patients

This paper deals with the mechanisms of activation of NADPH oxidase investigated using EBV-transformed human B lymphoblastoid cell lines (B cells) from normal subjects and from patients affected by X-linked chronic granulomatous disease (CGD). The results reported are as follows. 1) In normal B cells, the NADPH oxidase components p67phox, p40phox, p22phox, and gp91phox were less expressed than in polymorphonuclear neutrophils. 2) In normal B cells stimulated with PMA, p47phox, p67phox, and p40phox translocated to the membranes as occurs in polymorphonuclear neutrophils. 3) In CGD, B cells expressing p22phox in the absence of gp91phox, p47phox, p67phox, and p40phox did not translocate to the membranes after stimulation with PMA. 4) In PMA-stimulated B cells from an X91+ CGD patient in which p22phox was normally expressed and gp91phox was present but lacked five amino acids, translocation of p47phox to the membranes was unaffected, but p67phox and p40phox were poorly translocated, and the production of O2- was greatly reduced with respect to that by normal B cells. Taken together, these findings indicate that 1) a low expression of some NADPH oxidase components may represent the molecular basis of the low production of O2- in B lymphocytes; 2) the cytosolic components of NADPH oxidase cannot bind to p22phox on the membranes in the absence of gp91phox; 3) p47phox can translocate to the membranes independently of p67phox and p40phox; and 4) gp91phox may have a role in mediating and/or stabilizing the binding of p67phox and p40phox to the membranes of activated cells.     

Neurogenic pulmonary edema in fatal and nonfatal head injuries

Impaired pulmonary function is a frequent but poorly understood complication of acute head injury (HI). A potential early contributor to the pulmonary dysfunction seen in HI patients is neurogenic pulmonary edema (NPE). We hypothesized that NPE would occur early after HI and that it would have a continuum of clinical severity depending on the severity of the HI and associated intracranial hypertension. A large autopsy data base and inpatient HI data base were used to search for cases of NPE. Patients in the autopsy data base were stratified according to injury type and whether they died at the scene or within 96 hours of injury. There were significant (p < 0.0001, analysis of variance) elevations in lung weights in patients dying at the scene and within 96 hours from HI, compared with those dying from other noncentral nervous system injuries. No other organs studied showed significant weight increases. The incidence of NPE in isolated HI patients dying at the scene was 32%. In patients with isolated HI dying within 96 hours, the incidence of NPE was 50%. We found an inverse correlation (r = 0.62; p < 0.0014) between the initial cerebral perfusion pressure and the PaO2/FIO2 ratio despite a normal-appearing chest x-ray film. We conclude that NPE occurs frequently in HI patients. The process of edema formation begins early in the clinical course and is isolated to the lung.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nondestructive and Laboratory Evaluation of Damage Gradients in Concrete Structure Exposed to Cryogenic Temperatures

This paper discusses the use of pulse velocity, dynamic Young’s modulus of elasticity, and air permeability of concrete to evaluate the extent of damage and damage gradients to a concrete structure exposed to thermal shock and subsequent cryogenic temperatures. Liquefied natural gas (LNG) is maintained in liquid form at cryogenic temperatures typically below ?160°C (?260°F). The elevated concrete pedestal and precast concrete piles supporting a LNG storage tank were exposed to cryogenic temperatures following a leak of the LNG. The engineering assessment of the concrete structure consisted of a nondestructive evaluation phase using ultrasonic pulse velocity and a subsequent laboratory phase based on concrete cores. Dynamic Young’s modulus of elasticity and air permeability index of 25?mm (1?in.) thick disks sawed from the cores were determined. Analyzing concrete disks at 25?mm (1?in.) increments permitted assessment of changes in these properties with depth and enabled evaluation of depth of damage and damage gradients. The laboratory study confirmed that the distressed zone was limited to a near-surface area of concrete as suggested by the results of pulse velocity testing.     

Absence of PTEN/MMAC1 germ-line mutations in sporadic Bannayan-Riley-Ruvalcaba syndrome

Bannayan-Riley-Ruvalcaba syndrome (BRRS) is a rare hamartomatous polyposis condition with features of macrocephaly, intestinal juvenile polyposis, developmental delay, lipomas, and pigmentation spots of the male genitalia. An autosomal dominant pattern of inheritance exists in some families, but others appear as sporadic cases. Germ-line mutations in PTEN, a tyrosine phosphatase and putative tumor suppressor gene, have been demonstrated in two families with BRRS, and chromatin loss at the PTEN gene locus on chromosome 10q23 has been demonstrated in two BRRS patients. Germ-line mutations in PTEN have also been described in Cowden disease and in a small number of patients with juvenile polyposis syndrome. In an attempt to assess the nature of PTEN mutations in BRRS, we analyzed three sporadic BRRS patients for chromosome 10q23 deletion or PTEN germ-line mutations. All 3 patients demonstrated no loss of parental alleles at 15 chromosome 10q23 markers that encompassed the region of PTEN. In addition, analysis of mRNA and genomic DNA revealed no nonsense, missense, or insertion/deletion mutations of PTEN. Thus, other mechanisms besides mutation of PTEN must have occurred to cause BRRS in these patients. We speculate that BRRS and juvenile polyposis syndrome may have a heterogeneous etiology to cause their syndromes.     

Normal findings in vulvar examination and vulvoscopy

Expression of chicken and rat liver bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, in Escherichia coli encountered two common problems: the chicken enzyme was liable to proteolysis and the rat enzyme was prone to form inclusion bodies. Reducing the rate of protein synthesis by lowering either growth temperature or isopropyl-beta-D-thiogalactopyranoside (IPTG) concentration alleviated these two problems. Growth at 22 degrees C was optimum for expression of both enzymes. The optimum range of IPTG concentration for expression was 0.1-1 microM for the chicken liver bifunctional enzyme and 10 microM for rat liver enzyme. The components of growth medium also influenced the production. Compared with Luria-Bertani medium, an enriched medium-tryptone-phosphate medium-tripled the production of the active enzymes. Addition of glucose (0.2%) doubled the expression level of active chicken liver enzyme, but reduced the production of active rat liver enzyme to half the maximal level, while the phosphate in tryptone-phosphate medium had no effect on the production of the two enzymes.     

The trkA receptor mediates growth cone turning toward a localized source of nerve growth factor

We have developed an in vitro system for studying the interaction of chick dorsal root ganglion neuronal growth cones with a localized source of nerve growth factor (NGF) covalently conjugated to polystyrene beads. Growth cones rapidly turned and migrated under NGF-coated beads in a process that involved the initial formation of persistent contact with a bead, followed by directed flow of cytoplasm toward the point of contact. A role for the local activation of the high-affinity NGF receptor trkA was suggested by a strong inhibition of the turning response by (1) the addition of an antibody against the extracellular portion of trkA, (2) the elevation of the background concentration of NGF to saturate trkA, or (3) the presence of a concentration of the drug K252a that inhibits trkA activation. NGF binding to the pan-neurotrophin receptor p75 is also involved but is not required for turning. These data show a new role for both the trkA and the p75 receptors: the mediation of local events in the guidance of nerve growth cones.