Femoral artery pseudoaneurysms: risk factors, prevalence, and treatment options

Femoral artery pseudoaneurysms (PSA or false aneurysm) develop in about 1% of patients undergoing procedures that require femoral artery cannulation. PSA prolong hospitalization, consuming health-care resources, and result in significant morbidity. We designed a study to review the prevalence, risk factors, and treatment of PSA. We performed a retrospective, case-controlled study of patients diagnosed with PSA at a large, urban, tertiary-care teaching hospital. We reviewed 48 patients with PSA for our study. The estimated prevalence of PSA was 0.28%, with identical rates found for procedures done in the interventional radiology department and in the cardiac catheterization suite. Logistic regression identified three independent risk factors for developing PSA: being female (odds ratio 2.62), having an intervention performed (odds ratio 3.22), and not having a closure device used (odds ratio 10.2). Patients with PSA had longer hospital length of stay than that of patients without PSA. We found no statistically significant difference in failure or complication rates for the four treatment options and that spontaneous resolution of PSA does not correlate with its size. Thrombin injection and observation are effective, low-complication treatment options.     

Dependence of muscle VO2 on blood flow dynamics at onset of forearm exercise

The hypothesis that the rate of increase in muscle O2 uptake (VO2mus) at the onset of exercise is influenced by muscle blood flow was tested during forearm exercise with the arm either above or below heart level to modify perfusion pressure. Ten young men exercised at a power of approximately 2.2 W, and five of these subjects also worked at 1.4 W. Blood flow to the forearm was calculated from the product of blood velocity and cross-sectional area obtained with Doppler techniques. Venous blood was sampled from a deep forearm vein to determine O2 extraction. The rate of increase in VO2mus and blood flow was assessed from the mean response time (MRT), which is the time to achieve approximately 63% increase from baseline to steady state. In the arm below heart position during the 2.2-W exercise, blood flow and VO2mus both increased, with a MRT of approximately 30 s. With the arm above the heart at this power, the MRTs for blood flow [79.8 +/- 15.7 (SE)s] and VO2mus (50.2 +/- 4.0 s) were both significantly slower. Consistent with these findings were the greater increases in venous plasma lactate concentration over resting valued in the above heart position (2.8 +/- 0.4 mmol/l) than in the below heart position (0.9 +/- mmol/l). At the lower power, both blood flow and VO2mus also increased more rapidly with the arm below compared with above the heart. These data support the hypothesis that changes in blood flow at the onset of exercise have a direct effect on oxidative metabolism through alterations in O2 transport.     

Professionally-led support groups for cancer patients: an intervention in search of a model

OBJECTIVE: The objective of this review was to evaluate the clinical and research literature on professionally-led support groups for cancer patients and to propose an approach that would address patients' needs from diagnosis through survivorship. METHOD: Computerized and manual searches, including Medline and Psychlit searches, were completed for reviews of the literature. Twelve research studies were identified that met our criteria for in-depth review. A clinical model emerged from discussions of an oncology study group based on theoretical formulations and clinical experience with oncology patients. RESULTS: We found that recent research suggests that professionally-led support groups are increasing in number and that participation in such groups seems to enhance patients' quality, and possibly even quantity, of survival. Despite this, little effort has been made to determine what type of group may be appropriate for which patients and when in their course of care. CONCLUSIONS: If psychosocial intervention, in the form of professionally-led support groups for cancer patients, is to be more effective, it should be guided by a model which takes into consideration the changing needs and concerns of patients over the course of illness and, in many cases, recovery. The authors present an outline delineating what such a model might entail.     

Kinetic analysis of the in vitro inhibition, aging, and reactivation of brain acetylcholinesterase from rat and channel catfish by paraoxon and chlorpyrifos-oxon

In rats, the phosphorothionate insecticide parathion exhibits greater toxicity than chlorpyrifos, while in catfish the toxicities are reversed. The in vitro inhibition of brain acetylcholinesterase (AChE) by the active metabolites of the insecticides and the rates at which these inhibitor-enzyme complexes undergo reactivation/ aging were investigated in both species. Rat AChE was more sensitive to inhibition than catfish AChE as demonstrated by greater bimolecular rate constants (ki) in rats than in catfish. In both species, chlorpyrifos-oxon yielded higher ki's than paraoxon. The higher association constant (KA) of chlorpyrifos-oxon than paraoxon in both species and the lack of significant differences in the phosphorylation constants (kp) suggest that association of the inhibitor with AChE is the principal factor in the different potencies between these two inhibitors. In catfish, the ki of chlorpyrifos-oxon was 22-fold greater than that of paraoxon, while in rats it was 9-fold greater, suggesting that target site sensitivity is an important factor in the higher toxicity of chlorpyrifos to catfish but not in the higher toxicity of parathion to rats. No spontaneous reactivation of phosphorylated catfish AChE occurred and there were no differences in the first oder aging constants (ka) between compounds. For phosphorylated rat AChE, there were no differences in the first order reactivation constants (kr) but the ka for chlorpyrifos-oxon was significantly greater than that for paraoxon. This difference suggests that the steric positioning of the diethyl phosphate in the esteratic site is not the same between the two compounds, leading to differences in aging.     

Replication of O6-methylguanine-containing DNA by repair and replicative DNA polymerases

The biological consequences of O6-methylguanine (m6G) in DNA are well recognized. When template m6G is encountered by DNA polymerases, replication is hindered and trans-lesion replication results in the preferential incorporation of dTMP opposite template m6G. Thus, unrepaired m6G in DNA is both cytotoxic and mutagenic. Yet, cell lines tolerant to m6G in DNA have been isolated, which indicates that some cellular DNA polymerases may replicate m6G-containing DNA with reasonable efficiency. Previous reports suggested that mammalian pol beta could not replicate m6G-containing DNA, but we find that pol beta can catalyze trans-lesion replication; however, the lesion must reside in the optimal context for pol beta activity, single- or short nucleotide gapped substrates. Primed single-stranded DNA templates, with or without template m6G, were poor substrates for pol beta as reported in earlier studies. In contrast, trans-lesion replication by bacteriophage T4 DNA polymerase was observed for primed single-stranded DNA templates. Replication of m6G-containing DNA by T4 DNA polymerase required the gp45 accessory protein that clamps the polymerase to the DNA template. The rate-limiting step in replicating m6G-containing DNAs by both DNA polymerases tested was incorporation of dTMP across from the lesion.     

Neutrophil attractant protein-1 and monocyte chemoattractant protein-1 in human serum. Effects of intravenous lipopolysaccharide on free attractants, specific IgG autoantibodies and immune complexes

We recently found that normal human sera contain IgG antibodies against two chemoattractants, neutrophil attractant protein-1 (NAP-1/IL-8) and monocyte chemoattractant protein-1 (MCP-1), as well as immune complexes of these proteins. Intravenously administered LPS was reported to cause a sharp rise in serum NAP-1 concentration. Our study was designed to determine if LPS also caused an increase in MCP-1 and to measure associated changes in concentrations of antibody and immune complex. LPS caused a rise to peak within 2 to 3 h in serum concentrations of free NAP-1 and MCP-1, followed by an almost equally rapid fall toward base-line levels by about 5 h postinjection. MCP-1 concentration in sera from the 11 subjects rose to a peak of 330 +/- 52 pM. The peak value for NAP-1 was 80 +/- 11 pM. In 10 of the 11 subjects, free IgG autoantibody to MCP-1 decreased from a mean pre-LPS value of 1820 +/- 660 pM to a mean low of 53% of the respective initial values. Corresponding data for IgG anti-NAP-1 were a pre-LPS concentration of 216 +/- 7 pM, which decreased to a mean low of 44% of the respective initial values. The finding in some subjects of a rapid rise in free antibody after the nadir suggests the possibility of acute regulation of autoantibody secretion rates. Although the results suggested that LPS-induced chemoattractant combined with free antibody, serum concentrations of MCP-1-IgG or NAP-1-IgG did not increase, which points to an as yet unknown mechanism for trapping and elimination of the immune complexes.     

Assessment of pseudarthrosis in pedicle screw fusion: a prospective study comparing plain radiographs, flexion/extension radiographs, CT scanning, and bone scintigraphy with operative findings

Tribal warfare is a way of life in the highlands of Papua New Guinea. In earlier times direct confrontation with bushknives and axes, and shooting with bows and arrows were common. In recent years there have not been as many instances of direct confrontation with bushknives and axes, but the use of bows and arrows is on the rise. Since 1993, guns have been increasingly used, with devastating results. In 1993, 18 deaths were reported from tribal warfare in one area of the Southern Highlands Province, especially from gunshots, while in 1994, 24 deaths were reported from another area. A five-year review of tribal fight admissions to Mendi Hospital, from 1990 to 1994, showed an increase in the number and proportion of gunshot wounds; there were none in 1990-1992 but they constituted 18% of tribal fight injuries in 1993 and 33% in 1994.     

Peritraumatic dissociation and posttraumatic stress in male Vietnam theater veterans

OBJECTIVE: The aim of this study was to determine the reliability and validity of a proposed measure of peritraumatic dissociation and, as part of that effort, to determine the relationship between dissociative experiences during disturbing combat trauma and the subsequent development of posttraumatic stress disorder (PTSD). METHOD: A total of 251 male Vietnam theater veterans from the Clinical Examination Component of the National Vietnam Veterans Readjustment Study were examined to determine the relationship of war zone stress exposure, retrospective reports of dissociation during the most disturbing combat trauma events, and general dissociative tendencies with PTSD case determination. RESULTS: The total score on the Peritraumatic Dissociation Experiences Questionnaire--Rater Version was strongly associated with level of posttraumatic stress symptoms, level of stress exposure, and general dissociative tendencies and weakly associated with general psychopathology scales from the MMPI-2. Logistic regression analyses supported the incremental value of dissociation during trauma, over and above the contributions of level of war zone stress exposure and general dissociative tendencies, in accounting for PTSD case determination. CONCLUSIONS: These results provide support for the reliability and validity of the Peritraumatic Dissociation Experiences Questionnaire--Rater Version and for a trauma-dissociation linkage hypothesis: the greater the dissociation during traumatic stress exposure, the greater the likelihood of meeting criteria for current PTSD.