Kidney autotransplantation as a key solution for a BEVAR type IIIb endoleak.

OBJECTIVES: Target vessel endoleaks are one of the most common causes of revision procedures after a fenestrated or branched endovascular aneurysm repair. Usually, a redo stenting is an effective therapy, however, not always feasible. We present a case of a hybrid treatment for a type IIIb endoleak using the renal autotransplantation technique. METHODS: A 60-year-old man with a thoracoabdominal aortic aneurysm has been treated with a custom-made branched endoprosthesis. Occlusion of the bridging stent to the right renal artery with total infarction of the right kidney was identified one week later and conservatively managed. After four years, a type IIIb endoleak was identified. Endovascular treatment was attempted unsuccessfully. So, the endoleak was corrected using a hybrid strategy with the kidney autotransplantation technique. RESULTS: A left kidney autotransplantation followed by an aortic stent-graft relining with a tubular graft has been done uneventfully, in a phased manner. Postoperative computed tomography angiography confirmed the patency of vascular reconstructions with no endoleaks. No adverse events occurred during one year of follow-up. CONCLUSION: Our case highlights kidney autotransplantation as a viable solution for a hybrid treatment of target vessel endoleaks and shows that this technique can assist complex endovascular aortic reconstructions.

Endovascular Treatment of Renal Artery Thrombosis in Living-Donor Kidney Transplant Recipient With Severe COVID-19 Disease.

PURPOSE: Coronavirus disease 2019 (COVID-19) patients have a higher prevalence of micro-and macrovascular thrombotic events. However, the underlying mechanism for the increased thrombotic risk is not completely understood. Solid organ transplant recipients infected with SARS-CoV-2 may have an exponential increase in thrombotic risk and the best management strategy is unknown. CASE REPORT: A female kidney transplant recipient presented with allograft's renal artery thrombosis after a recent COVID-19 infection. Due to the risk of kidney failure or exclusion, catheter directed thrombolysis was performed. Residual thrombus was excluded using an endoprosthesis with an excellent result. There were no adverse events and kidney function improved. CONCLUSION: This paper reports the endovascular treatment of renal artery thrombosis in a living-donor kidney transplant recipient with severe COVID-19 disease.

Renal Autotransplantation for The Treatment of Renal Artery Aneurysm.

OBJECTIVE: Renal artery aneurysms are a rare condition; however, the rate of diagnosis has been increasing, because of the increasing use of complementary diagnostic methods. The best treatment strategy for RAAs remains controversial. Data on ex-vivo surgery associated with kidney autotransplantation are scarce. As a result, the goal of this study was to describe this technique and to report our results. METHODS: A retrospective monocentric study was undertaken using the clinical records and images of 35 patients diagnosed with renal artery aneurysm from 01/01/2010 to 31/12/2018. Indications for ex vivo surgery and autotransplantation were complex aneurysms with diameter >20 mm or rapid growth or symptomatic aneurysms or women wishing to become pregnant. Complex aneurysms were defined by anatomical criteria (bifurcation of the renal artery and its primary branches or hilar aneurysms) and/or physiological criteria (when time of warm ischemia in in-situ reconstruction is expected to last more than 45 minutes). The technique of ex-vivo surgery and autotransplantation consists of performing a nephrectomy, renal cooling, treatment of aneurysm in banking and implantation of the kidney in the homolateral iliac fossa. RESULTS: A total of 35 patients with 56 renal artery aneurysms (26 women, mean age 52.4 years-minimum and maximum 16 and 74 years) were included. Of these, 27 were treated by surgery and 8 were followed clinically. Among those treated surgically, 24 performed ex vivo surgery associated with autotransplantation. Regarding ex vivo surgery, nephrectomy was performed by laparoscopic surgery in 24 of the 27 surgeries, the mean surgical time was 5.3 hours, the median warm ischemia time was 4 minutes and the length of hospital stay was 12.2 days. Mortality was 0% and the kidney patency rate was 93% with a follow up of 47.2 months. Of the 17 patients with hypertension, 6 cured it, 4 improved and 7 maintained hypertension. CONCLUSION: Kidney autotransplantation appears to be efficient for most complex RAA with the possibility to minimize surgical aggression by performing laparoscopic nephrectomy.

Emergency Repair of a Ruptured Para-Renal Abdominal Aortic Aneurysm in a Patient with a Functional Renal Graft: A Case Report and Review of the Literature.

INDRODUCTION: Rupture of and abdominal aortic aneurysm (AAA) in a kidney transplant patient is a rare and rarely reported event. Emergent treatment can be challenging and should achieve effective aortic repair while minimizing ischemic damage to the renal graft during aortic cross-clamping. Several renal protective measures have been proposed such as permanent or temporary shunts, renal cold perfusion and general hypothermia. CASE REPORT: We report the effective treatment of a para-renal AAA in a patient with a functional renal allograft. A temporary extra-corporeal axillofemoral shunt was constructed to maintain graft's perfusion during open surgical repair. EVAR was not an option due to a short aortic neck. The postoperative period was complicated by colon ischemia and aortic graft infection. At 3 years follow-up the patient was well and graft's function was unchanged. CONCLUSION: This case is a reminder that renal graft protection must be accounted for when AAA rupture occurs in kidney transplant patients. We reviewed the literature to find previously reported cases and how they were managed.

Recycling of crushed concrete and steel slag in drainage structures of geotechnical works and road pavements.

A crushed concrete aggregate, processed from construction and demolition waste and a siderurgical aggregate, processed from electric arc furnace steel slag, were selected based on their very high availability worldwide and known technical feasibility to be used in construction works. Given the association of their presence to the possibility of reducing the drainage capacity of unbound granular layers of road pavements and drainage structures which they may be associated with, there are studies and regulations that do not recommend their use. The causes that are at the origin of restrictions are mainly the possibility of formation of tufa and recementation phenomena. This behaviour has also hampered their recycling in drainage structures of geotechnical works. Therefore, it was considered that it would be relevant to investigate the drainage capacity of those recycled aggregates, using a leachate produced in a municipal solid waste landfill and tap water. To reference their behaviour, two natural aggregates, a basalt and a limestone, were also studied under identical test conditions. The results obtained showed no reduction in the drainage capacity of the recycled aggregates, similarly to what was observed with the natural aggregates. The possibility of building drainage structures with the tested aggregates is verified.

Iliac side branch technique for repair of bilateral iliac artery aneurysms associated with a congenital pelvic kidney.

Pelvic kidney is a congenital anomaly with few literature reports of concomitant aortoiliac aneurysmal disease. When aneurysm repair is indicated, either open or endovascular, it poses a technical challenge, since kidney preservation is paramount. This paper reports a successful endovascular repair of bilateral common iliac artery aneurysms in a patient with a right congenital pelvic kidney, using iliac side branch technique.

Laparoscopic Resection of a Splenic Artery Aneurysm with Vascular Reconstruction During Pregnancy.

Splenic artery aneurysms (SAA) are more frequent in women and have a high rupture risk during pregnancy, with catastrophic outcomes. It is advisable to treat these aneurysms in pregnant and fertile women, whatever their diameter, given their increased risk for rupture. There are several therapeutic approaches: endovascular surgery using coil embolization or stent graft coverage; laparoscopic or open surgical resection with arterial reconstruction and ligation followed by splenectomy when necessary. This paper aims to report the successful treatment of SAA in second-trimester pregnant women using a laparoscopic approach with aneurysm resection and arterial reconstruction. This is a unique report of a minimally invasive approach with arterial reconstruction in a pregnant woman, thus reducing the risk of spleen infarction and potentially avoiding splenectomy.

Primary pituitary abscess: case report and suggested management algorithm.

PURPOSE: To describe a case of successful treatment of a patient with a rare primary pituitary abscess (PA) and propose a management algorithm. SUMMARY OF BACKGROUND DATA: PA is an infrequent entity that can be life-threatening if not promptly diagnosed and treated. PAs can be primary or secondary, the latter in the presence of sellar anomalies, risk factors or a systemic or local infection. Symptoms are nonspecific, making clinical suspicion imperative. Magnetic Resonance Imaging (MRI) is the radiological tool of choice. Despite some characteristic radiographic signs, oftentimes the diagnosis is not suspected until surgical exploration. Treatment includes transsphenoidal decompression surgery with sampling of purulent material and abscess wall for appropriate microbiological staining and cultures (bacteria, mycobacteria and fungus) and prolonged antibiotic treatment. Pituitary hormonal deficiencies must be addressed as well. METHODS AND RESULTS: We describe a case of a female patient who presented with headaches, anorexia and bitemporal hemianopsia. MRI revealed a peripherally enhancing sellar mass. Transsphenoidal surgery was performed, with intra-operative finding of purulent material. Cytology confirmed the presence of abundant leucocytes, but no pathogen was isolated. Patient completed three weeks of antibiotic therapy, with good clinical and radiological response. Headaches and visual deficits resolved. Hormonal substitution therapy was needed for six months after surgery. CONCLUSION: This report highlights the importance of early recognition and treatment of PAs. The diagnosis is commonly very difficult before surgery, due to overlapping clinical, radiological and laboratorial findings with various other pathologies. Prompt management, with surgical decompression and appropriate antibiotic treatment, typically results in a low mortality rate and higher chance of full recovery of pituitary function. We propose a management algorithm for sellar masses suspected of being PAs.

Efficacy and safety of sirolimus in the treatment of vascular anomalies: A systematic review.

OBJECTIVE: The management of vascular anomalies is complex and requires a multidisciplinary team with a combination of medical, surgical, and intervention treatments. Medical treatment is limited and has conflicting results. Off-label use of mammalian target of rapamycin inhibitors shows promising results. The objective of this study was to systematically evaluate the literature published about the efficacy and safety of sirolimus in the treatment of vascular anomalies. METHODS: A systematic review of the published literature was conducted using the PubMed database and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: There were 73 articles included: 2 randomized controlled studies, 2 nonrandomized prospective studies, and 69 retrospective case reports and case series. In total, 373 patients were included. Sirolimus was administered topically to 56 patients and orally to 317 patients. Sirolimus was highly effective in the treatment of vascular tumors associated with Kasabach-Merritt phenomenon (95.5% of the patients clinically improved and 93% had normalization of coagulopathy), venous malformations (size reduction was observed in 88.9% of patients), and lymphatic malformations (clinical improvement in 94.9% of patients). Topical sirolimus results were conflicting. Arteriovenous malformations were not improved by sirolimus. CONCLUSIONS: Low-level evidence suggests that sirolimus can improve the prognosis of vascular anomalies, most notably vascular tumors associated with life-threatening coagulopathy and venous and lymphatic malformations. Further research is needed to establish the benefits of sirolimus in the management of vascular anomalies.

Total Endovascular Aortic arch Replacement with Chimney/Sandwich Techniques.

Traditional open total zone 0 replacement of the aortic arch is one of the most complex, challenging, and demanding operative procedures in cardiovascular surgery, associated with significant morbidity (30-40%) and mortality (8-20%). Total endovascular zone 0 replacement of the aortic arch with chimney/sandwich techniques as described by Lobato and Camacho-Lobato is a feasible, less invasive, less demanding, and time-consuming option to hybrid and/or traditional open replacement of the aortic arch, particularly in the urgent/emergent settings. We are reporting a case of a 49-year-old patient with chronic type B aortic dissection complicated with descending thoracic aortic aneurysm and an unsuccessful zone 3 thoracic endovascular aortic repair, complicated with type Ia endoleak. He presented with an enlarging and symptomatic descending thoracic aortic aneurysm. An extended proximal (to the zone 0) and distal thoracic endovascular aortic repair was performed to ensure appropriate proximal and distal landing zones (C-TAG). Left subclavian artery endorevascularization was undertaken with periscope sandwich technique (Viabahn), while brachiocephalic trunk and left carotid artery endorevascularizations were carried on with the chimney graft technique (Viabahn). The procedure was uneventful and the one-month and one-year follow-up angio-computed tomography revealed no endoleaks, patency of all branches, and exclusion of the aneurysm.

Emergent Endovascular Treatment in Primary Ilio-enteric Fistula.

Aortoenteric fistula (AEF) is a rare cause of gastrointestinal (GI) bleeding. If not promptly diagnosed and treated, the associated mortality is very high. The role of endovascular treatment is not yet defined. In this article, we report a clinical case of a 94-year-old male patient admitted in the emergency department with rectal bleeding. Owing to the detection of a pulsatile abdominal mass, a computed tomography angiography (CTA) scan was performed, which established the diagnosis of aorto-enteric fistula due to a left common iliac artery aneurysm (CIAA) ruptured to the sigmoid colon and also revealed an abdominal aortic aneurysm (AAA) and an internal iliac artery aneurysm (IIAA). Given the age of the patient, general condition and technical difficulty inherent to the treatment of the IIAA by conventional surgery, we chose endovascular treatment. However, we wanted to avoid contact between the endograft and the colon orifice because of the risk of infection. The patient was treated emergently with an aorto-right uni-iliac graft and a femoro-femoral bypass, IIAA embolization and 2 left iliac excluders (at the origin of the common iliac and distally in the external iliac artery). It was decided to treat colon lesion conservatively. In this case, the aorto-uni-iliac graft excluded the aortic inline flow, the distal occluder prevented retrograde flow from the external iliac, and the embolization prevented retrograde flow and treated the IIAA. This way, no arterial pressure and no prosthetic material existed inside the ruptured artery, hopefully allowing the spontaneous closing of the orifice leading the sigmoid colon to heal. The postoperative period was uneventful, and the patient was discharged at the 8th postoperative day. The patient outcome is a strong argument on the merit of the treatment strategy.

Biliopancreatic diversion with duodenal switch (BPD-DS) and single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) result in distinct post-prandial hormone profiles.

BACKGROUND/OBJECTIVE: Biliopancreatic diversion with duodenal switch (BPD-DS) is the most effective bariatric intervention to treat morbid obesity and related disorders. Single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) is a new bariatric procedure devised with the purpose of simplifying the complexity of the BPD-DS technique while maintaining its efficacy. However, whether BPD-DS and SADI-S result in similar fasting and post-prandial hormone profiles has not yet been studied. Therefore, the purpose of this study was to assess and compare the hormone response to a standardized mixed meal in subjects operated with BPD-DS or SADI-S. SUBJECTS/METHODS: Subjects submitted to BPD-DS (n = 9) or SADI-S (n = 9) 1.5 years earlier on average, with no past nor current diabetes diagnosis underwent a liquid mixed-meal tolerance test (MMTT) to assess the baseline and post-prandial profile of glucose, enteropancreatic hormones and total bile acids. RESULTS: Fasting glucose, enteropancreatic hormones and total bile acids levels after BPD-DS and SADI-S were similar. After the MMTT, the response of subjects who underwent SADI-S was characterized by higher glucose (t = 30 min: p < 0.05; iAUC: 156.1 ± 46.2 vs. 103.4 ± 35.8 mmol/L × min, p = 0.02), GLP-1 (t = 30 min: p < 0.05; iAUC: 5388 ± 3010 vs. 2959.0 ± 2146 pmol/L × min, p = 0.02), glucagon (t = 30 min: p < 0.05; iAUC: 678.7 ± 295.2 vs. 376.9 ± 215.7 pmol/L × min, p = 0.02), insulin (t = 30 and 45 min: p < 0.05); and C-peptide levels (t = 30 and 45 min: p < 0.05), when compared to BPD-DS. CONCLUSIONS: The post-prandial hormone secretion profile after SADI-S is characterized by increased GLP-1, glucagon and insulin secretion, when compared to BPD-DS, which suggests the existence of different endocrine driven mechanisms leading to weight loss and metabolic improvement after the two procedures.

Effectiveness and Safety of Rivaroxaban Compared to Acenocumarol after Infrainguinal Surgical Revascularization.

BACKGROUND: Optimal antithrombotic therapy after lower limb infrainguinal revascularization remains a controversial topic. The use of anticoagulants, alone or in combination with antiplatelet drugs, can potentially improve patency rate and limb salvage, particularly in patients with risk factors for early thrombosis. Bleeding is the main complication of long-term anticoagulant use. New oral anticoagulants can represent an attractive alternative to the standard vitamin K antagonists. The objective of the study is to evaluate the effectiveness (bypass occlusion and major amputation) and safety (major bleeding and all-cause mortality) of rivaroxaban compared to acenocumarol after infrainguinal lower limb surgical revascularization. MATERIAL AND METHODS: Retrospective cohort study of patients with peripheral arterial disease submitted to lower limb infrainguinal bypass revascularization with vein or expanded polytetrafluoroethylene conduit, who were anticoagulated with acenocumarol or rivaroxaban after hospital discharge. Patients with proximal revascularization, revascularization due to any pathology other than peripheral arterial disease, coagulation disorder, stroke or acute myocardial infarction in less than 30 days, glomerular filtration rate <15 mL/min, or on hemodialysis were excluded. RESULTS: One hundred nine patients were included (78.9% male), with a mean age of 64.8 years. After hospital discharge, 40 patients (36.7%) were medicated with rivaroxaban and 69 patients (63.3%) with acenocumarol. At 1 year of follow-up, patients under rivaroxaban and acenocumarol presented comparable major amputation rates (12.5 % vs. 10.1%, P = 0.756), bypass occlusion (22.5% vs. 24.6 %, P = 0.769), and mortality rate (10% vs. 8.7%, P = 0.756). Major bleeding occurred in 13.8% of patients. Patients with renal dysfunction had significantly higher bleeding risk with acenocumarol (45.5% vs. 0%, P = 0.028) compared to rivaroxaban, while patients with normal renal function presented similar bleeding rates with both anticoagulants (6.1% vs. 6.4%, P = 0.953). CONCLUSIONS: Rivaroxaban has equivalent effectiveness to acenocumarol after infrainguinal bypass revascularization, with similar occlusion, major amputation, and mortality rates. Rivaroxaban has an improved safety profile in patients with moderate renal dysfunction due to a significantly lower incidence of major bleeding. In patients with normal renal function, rivaroxaban and acenocumarol present equivalent major bleeding rates.

HAS-BLED Score Predicts the Risk of Major Bleeding in Chronic Anticoagulation after Lower Limb Surgical Revascularization.

BACKGROUND: Anticoagulant drugs are sometimes used after lower limb surgical bypass to improve patency. There are no bleeding risk scores validated specifically for patients with peripheral arterial disease. The HAS-BLED (hypertension, abnormal renal or liver function, stroke, history of or predisposition to bleeding, labile international normalized ratio (INR), elderly age [>65 years], and drugs or alcohol) score is a validated and frequently used tool to estimate the risk of major bleeding in patients receiving anticoagulation for atrial fibrillation. The objective of this study was to access the efficacy of the HAS-BLED score in predicting bleeding risk after lower limb bypass revascularization. METHODS: This study involved "secondary analysis of a retrospective database that includes patients with lower limb revascularization that was anticoagulated with acenocoumarol after hospital discharge." Consecutive patients treated between January 2014 and May 2016 were included. Patients previously on anticoagulants and patients on hemodialysis were excluded. RESULTS: Sixty-nine patients were included, 73.9% were males, with a mean age of 65 years. At 1-year follow-up, major bleeding occurred in 18.8% of patients. In this study, 52.1% of patients had HAS-BLED score ≥3. This subgroup had increased incidence of major bleeding: 33.3% compared to 0 risk factor (0%), 1 risk factor (0%), and 2 risk factors (4.2%) (P = 0.001). CONCLUSIONS: In this retrospective analysis, HAS-BLED score presented good association with major bleeding risk. It can be used as a tool for decision-making for the prescription of anticoagulants after lower limb revascularization. The prevalence of high scores is substantial, presuming high bleeding risk in this high-risk population.

Hemodialysis Acess - A Creative Attitude is Necessary.

Creating and maintaining a functional vascular access (VA) is a critical factor in the survival of a dialysis patient. It implies a creative attitude either to maintain its functionality or to build a new one wherever possible, being it autologous or synthetic. We describe the VA history of a 59 years-old male patient, with extreme obesity, which started in 2012 with failed attempts of VA construction in both forearms until a functional brachiocephalic arteriovenous fistula (AVF) in the right upper limb was achieved. However, it required ligation due to severe venous hypertension secondary to central venous disease related to previous CVC use. As he had no good superficial conduit in the left arm we decided to harvest the arterialized right cephalic vein and implant it in the left arm, creating an autologous arteriovenous shunt between the brachial artery and axillary vein (AV). Despite initial patency, it failed irreversibly approximately one year after creation. As no more superficial veins were available in the upper limbs, a prosthetic access was the next step. We decided for a hybrid graft (HG) between the left brachial artery and the AV because of the patient's biotype and scarred axilla that impeded a safe re-intervention on the AV. This graft was used between 2015 and 2017 with multiple interventions to maintain patency. In 2017 a significant diffuse prosthesis deterioration and reduced AVF flow were noticed with no possible segmental reconstruction. We were then forced to proceed with subtotal graft substitution preserving the outflow stented segment of the HG, using an early cannulation graft to prevent CVC use. After this successful reconstruction, the patient started hemodialysis on the following day with no intercurrences registered.

[Hilar Renal Artery Aneurysm - Ex-vivo Reconstruction and Autotransplantation]. / Aneurisma Hilar da Artéria Renal - Reconstrução Ex-vivo e Autotransplante.

Renal artery aneurysm (RAA) is a rare entity with an estimated prevalence of 0.09%. The majority present asymptomatically and the diagnosis is made incidentally during an imaging test. Indications to treat have been subject of intense debate, nevertheless, there seems to be some consensus that RAA's greater than 2 cm in diameter, expanding, with thrombus or in pregnant women should be treated. Treatment options vary between surgical or endovascular approach. Hilar RAA presents a therapeutic challenge because of their anatomic location and may require extracorporeal arterial reconstruction and auto-transplantation. We describe a 71-year-old woman, with an incidentally diagnosed complex RAA, following the study for an abdominal discomfort. Computed tomographic angiography revealed a 13mm, saccular aneurysm located at the right renal hilum. We performed hand-assisted laparoscopic nephrectomy with ex-vivo repair of the RAA. The intervention and postoperative course were uneventful. At six months of follow up the patient keeps a well-functioning auto-transplant. RAA may be nowadays more frequently diagnosed due to the increasing use of imaging techniques. Hand- -assisted laparoscopic nephrectomy with ex-vivo repair and auto-transplantation is a challenging but feasible option for treating hilar RAA.

O aneurisma da artéria renal é uma entidade rara com uma prevalência estimada de 0.09% na população geral. A sua maioria apresenta-se de forma assintomática sendo o diagnóstico feito de forma incidental durante o estudo imagiológico por outra suspeita. As indicações para o seu tratamento têm vindo a ser alvo de grande debate na literatura contudo, parece haver algum consenso no sentido de tratar aqueles maiores que 2 cm de diâmetro, com crescimento ao longo do período de vigilância, na presença de trombo e em mulheres grávidas. As opções de tratamento variam entre cirurgia direta ou endovascular. Os aneurismas hilares representam um desafio em termos de abordagem cirúrgica pela sua localização requerendo em algumas circunstâncias reconstrução extracorporal e auto-transplante renal. Os autores descrevem um caso clínico de uma doente do sexo feminino, 71 anos de idade, a quem tinha sido incidentalmente diagnosticado um aneurisma hilar da artéria renal, no seguimento de estudo por desconforto abdominal. O estudo por angiotomografia computorizada revelou um aneurisma de 13mm, de conformação sacular, localizado a nível do hilo renal direito. Procedeu-se a nefrectomia via laparoscopia e reparação ex-vivo do aneurisma. O procedimento decorreu sem intercorrência bem como o seguimento efetuado à doente, mantendo-se o enxerto funcionante aos seis meses. O aneurisma da artéria renal é, hoje em dia, mais frequentemente diagnosticado no contexto do crescente uso de técnicas de exame imagiológicas. A nefrectomia via laparoscopia e reparação ex-vivo seguida de auto-transplante é um procedimento desafiante mas exequível com elevada taxa de sucesso no tratamento desta patologia.

Topography of human cytochrome b5/cytochrome b5 reductase interacting domain and redox alterations upon complex formation.

Cytochrome b5 is the main electron acceptor of cytochrome b5 reductase. The interacting domain between both human proteins has been unidentified up to date and very little is known about its redox properties modulation upon complex formation. In this article, we characterized the protein/protein interacting interface by solution NMR and molecular docking. In addition, upon complex formation, we measured an increase of cytochrome b5 reductase flavin autofluorescence that was dependent upon the presence of cytochrome b5. Data analysis of these results allowed us to calculate a dissociation constant value between proteins of 0.5±0.1µM and a 1:1 stoichiometry for the complex formation. In addition, a 30mV negative shift of cytochrome b5 reductase redox potential in presence of cytochrome b5 was also measured. These experiments suggest that the FAD group of cytochrome b5 reductase increase its solvent exposition upon complex formation promoting an efficient electron transfer between the proteins.