Intraprocedural Use of the Novel Protrieve Sheath Removes Embolus During Mechanical Thrombectomy of a Complex Iliocaval Deep Vein Thrombosis

Extension of proximal deep vein thrombosis (DVT) into the inferior vena cava (IVC) complicates treatment with mechanical thrombectomy, as the presence of IVC thrombus increases embolization risks. In the case of a 39-year-old man with left-sided iliocaval DVT, the novel Protrieve sheath (Inari Medical, Irvine, California) was intraprocedurally placed in the IVC to ensure such complications would not outweigh the benefits of intervention. During successful thrombectomy, the sheath's wall-apposing funnel trapped and removed procedural embolus from the IVC, with no complications occurring. Studies to determine whether the device can broadly improve the safety of complex DVT procedures are warranted.

Sesamum indicum Oleosin L improves oil packaging in Nicotiana benthamiana leaves

Plant oil production has been increasing continuously in the past decade. There has been significant investment in the production of high biomass plants with elevated oil content. We recently showed that the expression of Arabidopsis thaliana WRI1 and DGAT1 genes increase oil content by up to 15% in leaf dry weight tissue. However, triacylglycerols in leaf tissue are subject to degradation during senescence. In order to better package the oil, we expressed a series of lipid droplet proteins isolated from bacterial and plant sources in Nicotiana benthamiana leaf tissue. We observed further increases in leaf oil content of up to 2.3-fold when we co-expressed Sesamum indicum Oleosin L with AtWRI1 and AtDGAT1. Biochemical assays and lipid droplet visualization with confocal microscopy confirmed the increase in oil content and revealed a significant change in the size and abundance of lipid droplets.

Delayed referral of venous ulcers increases resource usage

OBJECTIVE

Venous insufficiency is often not readily recognized as a contributing etiology to nonhealing wounds by nonvascular surgery specialists, potentially delaying appropriate treatment to achieve wound healing and increasing healthcare costs. The objective of the present study was to understand the time and resources used before the definitive treatment of venous ulcers.

METHODS

A single-institution retrospective medical record review of C6 patients undergoing radiofrequency saphenous and perforator vein ablation from May 2016 to January 2018 identified 56 patients with 67 diseased limbs. The numbers of inpatient, emergency department, and wound care visits and the intervals to vein ablation from the initial evaluation of the ulceration by a healthcare provider were collected. The demographics, comorbidities, previous venous interventions, wound characteristics, duplex ultrasound imaging, and available wound healing follow-up through July 2018 were assessed for all patients.

RESULTS

For the 67 limbs examined, 588 total healthcare visits were performed for wound assessment before a referral to a vascular surgeon, with 413 visits at a wound care center (70% of all visits). Other specialty visits included emergency medicine (17.9% of limbs) and rheumatology (22.4% of limbs). Six patients (nine limbs) were admitted to inpatient services for treatment of their ulceration. Overall, the patients were seen an average of 8.6 ± 9.7 times for their ulcer with the wound center before determination of a contributing venous etiology and subsequent treatment. These visits translated to a median of 230 days (interquartile range, 86.5-1088 days) between the first identification of the ulcer by healthcare providers and subsequent accurate diagnosis and definitive treatment of their venous disease with radiofrequency saphenous and perforator vein ablation. After intervention, 18.64% of the limbs had healed at 1 month, 33.92% had healed at 3 months, 50% had healed at 6 months, and 82.92% had healed by 12 months.

CONCLUSIONS

An earlier and accurate diagnosis of the venous contribution to ulcers and subsequent appropriate treatment of venous etiologies in wound formation by a vascular venous specialist could significantly improve healing and minimize resource usage.

Optimization of factors for the prevention of spinal cord ischemia in thoracic endovascular aortic repair

OBJECTIVES

Spinal cord ischemia following thoracic endovascular aortic repair (TEVAR) is a devastating complication. This study seeks to demonstrate how a standardized protocol to prevent spinal cord ischemia affects incidence in patients undergoing TEVAR.

METHODS

Using CPT codes 33880 and 33881, all TEVAR procedures performed at a single tertiary care center from January 2017 to December 2018 were examined. Patients who had concomitant ascending aortic repairs or a TEVAR for traumatic indications were excluded from analysis, leaving 130 TEVAR procedures. Comorbid conditions, procedural characteristics, extent of coverage, peri-procedural management strategies, and post-operative outcomes were collected and analyzed retrospectively.

RESULTS

One hundred thirty patients undergoing TEVAR were examined for four perioperative variables: postoperative hemoglobin greater than 10 g/dL, subclavian revascularization, preoperative spinal drain placement, and somatosensory evoked potential monitoring (SSEP). All conditions were met in 46.2% (60/130) of procedures; 37.8% (28/74) in emergent/urgent cases and 61.5% (32/52) in elective cases. Of patients who required subclavian coverage, 87.1% (54/62) underwent subclavian revascularization; 70.8% (92/130) of patients received spinal drains preoperatively; 68.5% (89/130) of patients had SSEP monitoring; 73.8% (93/130) of patients obtained a postoperative hemoglobin of >10 g/dL. Out of all patients, two (1.5%) developed spinal cord ischemia.

CONCLUSION

Incidence of spinal cord ischemia in our cohort was low at 1.5% (2/130). Individual and bundled interventions for the prevention of spinal cord ischemia were unable to demonstrate a statistically significant effect given the low rate. Nonetheless, we advocate for a proactive approach for the prevention of spinal cord ischemia given our experience in this complex population.

A comparison of cyanoacrylate glue and radiofrequency ablation techniques in the treatment of superficial venous reflux in CEAP 6 patients

OBJECTIVE

Venous leg ulcers (CEAP [clinical, etiologic, anatomic, pathophysiologic] class 6) represent the most severe form of chronic venous insufficiency. As closure techniques for superficial venous reflux evolve, direct outcome comparisons of treatments are integral, because many studies have already demonstrated that early endovenous intervention improves wound healing. The present study compared the rates of venous wound healing between two techniques of superficial vein closure: ClosureFast radiofrequency ablation (RFA) and adhesive closure (VenaSeal; both Medtronic, Inc, Minneapolis, Minn).

METHODS

We performed a multi-institutional retrospective review of all patients with CEAP class 6 who had undergone closure of their truncal veins from 2015 to 2020. Patients undergoing ClosureFast RFA were compared with those undergoing VenaSeal adhesive closure. The primary endpoint was the interval to wound healing from initial vein closure. The secondary endpoints included ulcer recurrence and infection rates. Bivariate analysis involved the χ², Fisher exact, t, and Wilcoxon rank sum tests. Multivariate linear regression analysis was used to examine the factors affecting the time to wound healing in the most predictive model. Statistical significance was defined as P < .05.

RESULTS

A total of 119 patients with CEAP 6 were included, with a median follow-up of 105 days (interquartile range, 44-208 days). Of the 119 limbs, 68 were treated with RFA and 51 with VenaSeal. Significantly more patients undergoing RFA had had a history of deep vein thrombosis (29% vs 10%; P = .01) and deep venous reflux (82% vs 51%; P = .003). The VenaSeal patients were older (72 years vs 65 years; P = .02) with a greater rate of coronary artery disease (16% vs 37%; P = .01). The median time to wound healing after the procedure was significantly shorter for VenaSeal than for RFA (43 vs 104 days; P = .001). Two RFA patients developed a postprocedure infection. The ulcer recurrence rate was 19.3% (22.1% for RFA vs 13.7% for VenaSeal; P = .25). On multivariate analysis, the treatment modality was the only significant predictor of the time to wound healing. When stratified by ulcer size as small (<3 cm²) vs large (>3 cm²), VenaSeal closure healed the wounds significantly faster for all ulcers.

CONCLUSIONS

ClosureFast and VenaSeal are both safe and effective treatments to eliminate truncal venous insufficiency. VenaSeal showed a superior time to wound healing compared with ClosureFast in both large and small ulcers.

Identification of Genes Involved in Lipid Biosynthesis through de novo Transcriptome Assembly from Cocos nucifera Developing Endosperm

Cocos nucifera (coconut), a member of the Arecaceae family, is an economically important woody palm that is widely grown in tropical and subtropical regions. The coconut palm is well known for its ability to accumulate large amounts of oil, approximately 63% of the seed weight. Coconut oil varies significantly from other vegetable oils as it contains a high proportion of medium-chain fatty acids (MCFA; 85%). The unique composition of coconut oil raises interest in understanding how the coconut palm produces oil of a high saturated MCFA content, and if such an oil profile could be replicated via biotechnology interventions. Although some gene discovery work has been performed there is still a significant gap in the knowledge associated with coconut's oil production pathways. In this study, a de novo transcriptome was assembled for developing coconut endosperm to identify genes involved in the synthesis of lipids, particularly triacylglycerol. Of particular interest were thioesterases, acyltransferases and oleosins because of their involvement in the processes of releasing fatty acids for assembly, esterification of fatty acids into glycerolipids and protecting oils from degradation, respectively. It is hypothesized that some of these genes may exhibit a strong substrate preference for MCFA and hence may assist the future development of vegetable oils with an enriched MCFA composition. In this study, we identified and confirmed functionality of five candidate genes from the gene families of interest. This study will benefit future work in areas of increasing vegetable oil production and the tailoring of oil fatty acid compositions.

A reconfigured Kennedy pathway which promotes efficient accumulation of medium-chain fatty acids in leaf oils

Medium-chain fatty acids (MCFA, C6-14 fatty acids) are an ideal feedstock for biodiesel and broader oleochemicals. In recent decades, several studies have used transgenic engineering to produce MCFA in seeds oils, although these modifications result in unbalance membrane lipid profiles that impair oil yields and agronomic performance. Given the ability to engineer nonseed organs to produce oils, we have previously demonstrated that MCFA profiles can be produced in leaves, but this also results in unbalanced membrane lipid profiles and undesirable chlorosis and cell death. Here we demonstrate that the introduction of a diacylglycerol acyltransferase from oil palm, EgDGAT1, was necessary to channel nascent MCFA directly into leaf oils and therefore bypassing MCFA residing in membrane lipids. This pathway resulted in increased flux towards MCFA rich leaf oils, reduced MCFA in leaf membrane lipids and, crucially, the alleviation of chlorosis. Deep sequencing of African oil palm (Elaeis guineensis) and coconut palm (Cocos nucifera) generated candidate genes of interest, which were then tested for their ability to improve oil accumulation. Thioesterases were explored for the production of lauric acid (C12:0) and myristic (C14:0). The thioesterases from Umbellularia californica and Cinnamomum camphora produced a total of 52% C12:0 and 40% C14:0, respectively, in transient leaf assays. This study demonstrated that the introduction of a complete acyl-CoA-dependent pathway for the synthesis of MFCA-rich oils avoided disturbing membrane homoeostasis and cell death phenotypes. This study outlines a transgenic strategy for the engineering of biomass crops with high levels of MCFA rich leaf oils.

Thioesterase overexpression in Nicotiana benthamiana leaf increases the fatty acid flux into triacylgycerol

Increasing the oil content of leafy biomass is emerging as a sustainable source of vegetable oil to meet global demand. Transient gene expression in leaf provides a reproducible platform to study the effect of transgenes on lipid biosynthesis. We first generated a transgenic Nicotiana benthamiana line containing high levels of triacylglycerol in the leaf tissue (31.4% by dry weight) by stably expressing WRI1, DGAT1 and OLEOSIN. We then used this line as a platform to test the effect of three Arabidopsis thaliana thioesterases (FATA1, FATA2 and FATB). Further increases in leaf oil content were observed with biochemical and lipid assays revealing an increase in the export of fatty acids from the chloroplast and a modification in the oil profile.

Metabolic engineering of medium-chain fatty acid biosynthesis in Nicotiana benthamiana plant leaf lipids

Various research groups are investigating the production of oil in non-seed biomass such as leaves. Recently, high levels of oil accumulation have been achieved in plant biomass using a combination of biotechnological approaches which also resulted in significant changes to the fatty acid composition of the leaf oil. In this study, we were interested to determine whether medium-chain fatty acids (MCFA) could be accumulated in leaf oil. MCFA are an ideal feedstock for biodiesel and a range of oleochemical products including lubricants, coatings, and detergents. In this study, we explore the synthesis, accumulation, and glycerolipid head-group distribution of MCFA in leaves of Nicotiana benthamiana after transient transgenic expression of C12:0-, C14:0-, and C16:0-ACP thioesterase genes. We demonstrate that the production of these MCFA in leaf is increased by the co-expression of the WRINKLED1 (WRI1) transcription factor, with the lysophosphatidic acid acyltransferase (LPAAT) from Cocos nucifera being required for the assembly of tri-MCFA TAG species. We also demonstrate that the newly-produced MCFA are incorporated into the triacylglycerol of leaves in which WRI1 + diacylglycerol acyltransferase1 (DGAT1) genes are co-expressed for increased oil accumulation.

Role of serotonin transporter inhibition in the regulation of tryptophan hydroxylase in brainstem raphe nuclei: time course and regional specificity

Drugs that selectively inhibit the serotonin transporter (SERT) are widely prescribed for treatment of depression and a range of anxiety disorders. We studied the time course of changes in tryptophan hydroxylase (TPH) in four raphe nuclei after initiation of two different SERT inhibitors, citalopram and fluoxetine. In the first experiment, groups of Sprague-Dawley rats received daily meals of rice pudding either alone (n=9) or mixed with citalopram 5 mg/kg/day (n=27). Rats were sacrificed after 24 h, 7 days or 28 days of treatment. Sections of dorsal raphe nucleus (DRN), median raphe nucleus (MRN), raphe magnus nucleus (RMN) and caudal linear nucleus (CLN) were processed for TPH immunohistochemistry. Citalopram induced a significant reduction in DRN TPH-positive cell counts at 24 h (41%), 7 days (38%) and 28 days (52%). Similar reductions in TPH-positive cell counts were also observed at each timepoint in the MRN and in the RMN. In the MRN, citalopram resulted in significant reductions at 24 h (26%), 7 days (16%) and 28 days (23%). In the RMN, citalopram induced significant reductions of TPH-positive cell counts at 24 h (45%), 7 days (34%) and 28 days (43%). By contrast, no significant differences between control and treatment groups were observed in the CLN at any of the time points that we studied. To investigate whether these changes would occur with other SERT inhibitors, we conducted a second experiment, this time with a 28-day course of fluoxetine. As was observed with citalopram, fluoxetine induced significant reductions of TPH cell counts in the DRN (39%), MRN (38%) and RMN (41%), with no significant differences in the CLN. These results indicate that SERT inhibition can alter the regulation of TPH, the rate limiting enzyme for serotonin biosynthesis. This persistent and regionally specific downregulation of serotonin biosynthesis may account for some of the clinical withdrawal symptoms associated with drugs that inhibit SERT.