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Key Clinical Message Thirty-seven-year old female with hydrocephalus managed by a ventriculoatrial ( VA) shunt presented with upper body edema, dysphagia, and headache. Imaging demonstrated thrombosis of the superior vena cava ( SVC). Direct catheter thrombolysis led to resolution of thrombus burden. Superior vena cava thrombosis is a rare consequence of VA shunting and must be managed emergently. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus (HIV) infection causes chronic progressive immunodeficiency and immune dysregulaton. Although simple depletion of the major target of HIV infection, the CD4+ T cell, can explain much of the immunosuppression seen, there are multiple other factors contributing to the immune dysregulation. CD4+ T-cell depletion induces a range of homeostatic mechanisms that contribute to immune activation and cell turnover, providing a milieu conducive to further viral replication and cell destruction, resulting in functional defects in various lymphoid organs. These changes are progressive and in turn compromise the homeostatic processes. Further, the infection, like any other viral infection, provokes an active immune response consisting of both CD4+ and CD8+ T-cell responses. Both appear compromised, displaying aberrant memory cell production. While some of these defects result from viral variation and the chronicity of antigen presentation, other defects of memory cell production appear very early during the primary immune response limiting the viral specific T-cell responses from the outset. This, combined with the ability of the virus to escape any successful immune responses, results in an attenuated immune response that eventually becomes exhausted, characterized by progressive deficits in T-cell repertoire. Furthermore, negative regulatory mechanisms that normally control the immune response may be aberrantly invoked, perhaps directly by the virus, further compromising the efficacy of the immune response. Rational design of effective immunotherapies depends on a clear understanding of the processes compromising the immune response to HIV.Immunology and Cell Biology (2007) 85, 6–15. doi:10.1038/sj.icb.7100015; published online 5 December 2006 [ABSTRACT FROM AUTHOR]

The role of carotid endarterectomy (CEA) in stroke prevention is now better defined. However, its role in patients older than 79 years of age is controversial. This group of patients has been excluded in most clinical trials. In this study the authors reviewed their experience with CEA patients >79 years old. The records of all patients older than 79 years of age who underwent a CEA in a recent time period from January 1988 to December 1996 were retrospectively reviewed. Forty-one patients (31 men, 10 women) were identified by computer search. The indication for operation included transient ischemic attack in 12 (29.3%), amaurosis fugax in nine (22%), stroke in two (4.9%), and nonhemispheric symptoms in three (7.3%). Fifteen patients (36.6%) were asymptomatic. Medical risk factors included coronary artery disease in 26 (63.4%), hypertension in 22 (53.7%), and smoking in 12 (29.3%). The procedure was performed under EEG monitoring in all patients. General anesthesia was administered in 37 (90%) and regional anesthesia in four (10%). Shunts were used in four (10%) patients. The internal carotid artery was patched in 16 patients (39%). One patient (2.4%) developed a perioperative Stroke and only one patient developed perioperative myocardial infarction (MI). None of the patients died within 30 days of surgery. In addition to the one MI case, five patients developed minor complications. The average length of time for stay after CEA was 3.4 days. Patients were followed up for an average of 20.7 months. Six patients died during follow-up. Four of those died from an MI and two from a stroke. The authors conclude that with proper selection of patients, CEA is safe in the octogenarian. Age alone should not be a contraindication for CEA. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the results of extra-anatomic femorofemoral crossover bypass grafting to the anatomic iliofemoral bypass grafting procedure in the treatment of patients with unilateral iliac artery occlusive disease with respect to patency and limb salvage. The records of all patients with unilateral iliac artery disease who underwent revascularization between January 1988 and December 1995 at the University of Iowa Hospitals and Clinics (UIHC) were retrospectively reviewed; 108 patients were identified and divided into two groups. Group I (n=68; male/female=44/24) was composed of all patients who underwent a femorofemoral crossover extra-anatomic bypass. All patients who underwent an iliofemoral anatomic bypass constituted group II (n=40; male/female=24/16). The mean age for group I was 60 years (range 28–87) and for group II, 54 years (range 14–86). The medical risk factors between both groups were comparable. Except for the higher incidence of gangrene in group II the indications for surgery were comparable between both groups. A polytetrafluoroethylene graft was used in 88% of group I patients and in 90% of group II patients (NS). In the remaining patients, an autogenous vein conduit was used. Two patients from group I (2.9%) died in the perioperative period (NS). Graft patency was assessed by clinical evaluation, Doppler-derived ankle/brachial indices, and color duplex imaging. The cumulative primary and secondary patency rates, limb salvage, and patient survival were calculated by use of life table analysis (SE<0.1). The need for simultaneous outflow and inflow procedures at the time of surgery was comparable between both groups. The proportion of patients who underwent further revascularization during follow-up was also comparable. The 5-year primary and secondary graft patency rates were 81.7% and 90.3%, in group I and 61.3% and 80.5% in group II. Although the difference between both groups was not significant there was a tendency toward higher rates with femorofemoral bypass. The 5-year survival rates of 80.3% for group I and 73.3% for group II were comparable. These data suggest that there is no significant difference in the long-term results between the femorofemoral crossover bypass grafts and iliofemoral grafts. Both procedures result in acceptable patency and limb salvage rates. The femorofemoral bypass is, however, more attractive, for it can be performed under local anesthesia if needed and does not involve the creation of the retroperitoneal incision necessary with the iliofemoral bypass. [ABSTRACT FROM AUTHOR]

Mesogens containing four rings in the main core can accommodate one terminal and two nearby lateral chains on each outside aromatic ring. These compounds containing six chains present an enantiotropic nematic range which is influenced by the rigidity of the links. The conformational behaviour of the first methyleneoxy group within the chains was investigated by one and two dimensional 13C NMR. The sign of the jump in chemical shifts when entering the nematic phase indicates the folding of each lateral branch. Dipolar oscillations during cross-polarization contact provide the values of the bond order parameter. The two first lateral fragments do not behave in the same way, demonstrating the influence of the fragment along which the chain is back folded. [ABSTRACT FROM AUTHOR]