Susceptibility of inbred mice to rickettsiae of the spotted fever group.

A mouse strain susceptible to lethal infection with Rickettsia conorii was required for testing vaccine efficacy and for studying the immunology and pathogenesis of infection. Among 20 strains of inbred mice inoculated intraperitoneally with the Malish strain of R. conorii, the C3H/HeJ mouse strain was the most susceptible, with a 50% lethal dose of approximately 10 PFU. Infection of all mouse strains resulted in a measurable antibody response; the highest titers correlated with the greatest degree of rickettsial replication as measured by plaque assay of infected spleen homogenates. Inoculation of C3H/HeJ mice with 5.0 log10 organisms of strain Malish by the subcutaneous route did not result in lethal infection. The Casablanca and Moroccan strains of R. conorii were not lethal for C3H/HeJ mice and, in addition, produced plaques in L-929 cells morphologically distinct from those produced by the Malish strain. The only other spotted fever group rickettsia tested which produced a lethal infection in C3H/HeJ mice was Rickettsia sibirica. Sublethal infection with any of the spotted fever rickettsiae tested protected against lethal infection with R. conorii. These data established a lethal challenge system for examining the protective efficacy of spotted fever immunogens and presented evidence of biological variation among strains of R. conorii

Superficial femoral artery balloon angioplasty stent implantation-outcome stratified by type of follow-up evaluation: Arterial duplex imaging versus ankle-brachial index only

Objectives: Endovascular therapy with transluminal angioplasty with stent deployment has become a commonly performed intervention in the management of superficial femoral artery (SFA) occlusive disease. In-stent stenosis occurs in approximately 16% to 32% of patients at one-year follow-up and can lead to stent occlusion and symptom recurrence. Arterial duplex stent imaging (ADSI) of the stented segment can be diagnostic for recurrent stenosis, however, its uniform application and benefit is controversial. With this study we aim to determine whether follow-up with ADSI yielded a better outcome than those with Doppler and ankle-brachial index (ABI) follow-up alone. Methods: We performed a retrospective analysis collecting data of patients undergoing SFA stent implantation for occlusive disease at a tertiary care referral center between 2009 and 2016. Patients with PTA only, those with an in-stent restenosis, and those with no follow-up were excluded. The remaining patients were divided into those with at least one ADSI (ADSI group) and those with clinical/ABI follow-up only (ABI group). Variables analyzed included patients demographics, comorbidities, indication and procedural details. The two groups were compared via univariate analysis with respect to the following variables: patency, proximal/distal (relative to stent) progression and intervention, major adverse limb event, limb loss and mortality. Results: There were 238 patients with SFA stent implantation included in the study, 152 into ADSI and 86 into ABI. There was no difference in demographics and comorbidities between the groups. ADSI and ABI were homogenous regarding clinical presentation (claudication/critical limb ischemia ADSI 39.1%/60.9% vs ABI 37.6%/62.4%; P = .982) and Trans-Atlantic Inter-Society Consensus classification (P = .546). The 1-year outcome showed a similar primary patency rates for ADSI (63.8%) versus ABI (65.1%; P = .841). Both groups had improvement in assisted patency, however, ADSI had a higher assisted patency compared with ABI (81.6% vs 69.8%; P = .037). Secondary patency was also higher for ADSI (88.1%) vs ABI (72.9%; P = .003). Despite similar clinical presentations, ABI patients were more likely to undergo a major amputation (ABI 14.7% vs ADSI 3.4%; P = .002) at the 1-year follow-up. Conclusions: In SFA stent implantation, ADSI follow-up shows an advantage in assisted patency and secondary patency, which may contribute to a decreased rate of major amputation. Within the first year of follow-up evaluation of SFA stent implantation, ADSI would seem to be advantageous and consideration should be given to more uniform application of surveillance ADSI

Predictors of surgical site infection after open lower extremity revascularization

OBJECTIVE: Surgical site infection (SSI) after open lower extremity bypass (LEB) is a serious complication leading to an increased rate of graft failure, hospital readmission, and health care costs. This study sought to identify predictors of SSI after LEB for arterial occlusive disease and also potential modifiable factors to improve outcomes. METHODS: Data from a statewide cardiovascular consortium of 35 hospitals were used to obtain demographic, procedural, and hospital risk factors for patients undergoing elective or urgent open LEB between January 2012 and June 2015. Bivariate comparisons and targeted maximum likelihood estimation were used to identify independent risk factors of SSI. Adjusted odds ratios (ORs) were calculated for patient demographics, comorbidities, operative details, and hospital-level factors. RESULTS: Our study population included 3033 patients who underwent 703 femoral-femoral bypasses, 1431 femoral-popliteal bypasses, and 899 femoral-distal vessel bypasses. An SSI was diagnosed in 320 patients (10.6%) ≤30 days after the index operation. Adjusted patient and procedural predictors of SSI included renal failure currently requiring dialysis (OR, 4.35; 95% confidence interval [CI], 3.45-5.47; P \u3c .001), hypertension (OR, 4.29; 95% CI, 2.74-6.72; P \u3c .001), body mass index ≥25 kg/m2 (OR, 1.78; 95% CI, 1.23-2.57; P = .002), procedural time \u3e240 minutes (OR, 2.95; 95% CI, 1.89-4.62; P \u3c .001), and iodine-only skin preparation (OR, 1.73; 95% CI, 1.02-2.91; P = .04). Hospital factors associated with increased SSI included hospital size \u3c500 beds (OR, 2.22; 95% CI, 1.09-4.55; P = .028) and major teaching hospital (OR, 1.66; 95% CI, 1.07-2.58; P = .024). SSI resulted in increased risk of major amputation and surgical reoperation (P \u3c .01), but did not affect 30-day mortality. CONCLUSIONS: SSI after LEB is associated with an increase in rate of amputation and reoperation. Several patient, operative, and hospital-related risk factors that predict postoperative SSI were identified, suggesting that targeted improvements in perioperative care may decrease complications and improve vascular patient outcomes

Outcome Benefit of Arterial Duplex Stent Imaging After Superficial Femoral Artery Stent Implantation

INTRODUCTION: In-stent stenosis is a frequent complication of superficial femoral artery (SFA) endovascular intervention and can lead to stent occlusion and/or symptom recurrence. Arterial duplex stent imaging can be used in the surveillance for recurrent stenosis, however, its uniform application is controversial. In this study, we aim to determine, in patients undergoing SFA stent implantation, whether surveillance with arterial duplex stent imaging yielded a better outcome than those with only ankle-brachial index (ABI) follow-up. METHODS: We performed a retrospective analysis of all patients undergoing SFA stent implantation for occlusive disease at a tertiary care referral center between 2009 and 2016. The patients were divided into those with arterial duplex stent imaging (ADSI group) and those with ankle brachial index follow-up only (ABI group). Life table analysis was performed, comparing stent patency, major adverse limb event, limb salvage, and mortality between groups. RESULTS: Two hundred forty-eight patients with SFA stent implantation were included: 160 into ADSI; 88 into ABI. Groups were homogenous regarding clinical indication (claudication/critical limb ischemia ADSI 39/61% vs ABI 38/62%; P = 0.982) and TASC classification (TASC A/B/C/D for ADSI 17/45/16/22% and ABI 21/43/16/20%; P = 0.874). Primary patency was similar between groups at 12/36/56 months: ADSI (65/43/32%) vs ABI (69/34/34%) (P = 0.770), whereas ADSI patients showed an improved assisted primary patency (84/68/54%) vs ABI (76/38/38%; P = 0.008) and secondary patency. There was a greater freedom from major adverse limb event in the ADSI group (91/76/64%) vs the ABI group (79/46/46%) (P \u3c 0.001) at 12/36/56 months follow-up. Arterial duplex stent imaging patients were more likely to undergo an endovascular procedure as their initial post-SFA stent implantation intervention (P = 0.001) whereas ABI patients were more likely to undergo an amputation (P \u3c 0.001). CONCLUSIONS: In SFA stent implantation, patients with arterial duplex stent imaging follow-up demonstrate an advantage in assisted-primary patency and secondary patency and are more likely to undergo an endovascular re-intervention. These factors likely effected a decrease in major adverse limb events, indicating the benefit of a more universal adoption of post-SFA stent implantation follow-up arterial duplex stent imaging

Radar Perspective of the Aristarchus Pyroclastic Deposit and Implications for Future Missions

The Aristarchus plateau represents one of the most complex volcanic provinces on the lunar surface and is host to the largest pyroclastic deposit on the Moon. Lunar pyroclastic deposits offer a window into the Moon’s interior and represent a valuable resource to support a sustained human presence. We present a new analysis of the Aristarchus pyroclastic deposit using Mini-RF bistatic radar data at wavelengths of 4.2 and 12.6 cm. Building on previous Earth-based Arecibo Observatory radar studies at 12.6 and 70 cm, we place further constraints on the spatial extent of the pyroclastic deposit and investigate the clast size distribution and provenance of foreign material distributed within the formation. Concentrations of blocky material >0.5 cm in diameter and suspended within the upper decimeters of the pyroclastic deposit are associated with potential buried mare flows along the rim of Vallis Schröteri and discrete pockets of primary material ejected by the Aristarchus impact. Unraveling the deposit from nonpyroclastic materials and the surrounding landscape creates new constraints with which to reconstruct the volcanic history of the region. From a future mission perspective, the identification of primary Aristarchus material distributed across the plateau offers an opportunity to sample diverse volcanic lithologies within an area that could be sampled by a single Commercial Lunar Payload Services mission. In terms of lunar resource in situ utilization, such ejected material also represents a contaminant; thus, radar data provide an invaluable tool to identify pristine pyroclastic material for mission planners