Stereodivergent 1,3-difunctionalization of alkenes by charge relocation

Alkenes are indispensable feedstocks in chemistry. Functionalization at both carbons of the alkene-1,2-difunctionalization-is part of chemistry curricula worldwide1. Although difunctionalization at distal positions has been reported2-4, it typically relies on designer substrates featuring directing groups and/or stabilizing features, all of which determine the ultimate site of bond formation5-7. Here we introduce a method for the direct 1,3-difunctionalization of alkenes, based on a concept termed 'charge relocation', which enables stereodivergent access to 1,3-difunctionalized products of either syn- or anti-configuration from unactivated alkenes, without the need for directing groups or stabilizing features. The usefulness of the approach is demonstrated in the synthesis of the pulmonary toxin 4-ipomeanol and its derivatives.

Identification of a Protein Arginine Methyltransferase 7 (PRMT7)/Protein Arginine Methyltransferase 9 (PRMT9) Inhibitor

Less studied than the other protein arginine methyltransferase isoforms, PRMT7 and PRMT9 have recently been identified as important therapeutic targets. Yet, most of their biological roles and functions are still to be defined, as well as the structural requirements that could drive the identification of selective modulators of their activity. We recently described the structural requirements that led to the identification of potent and selective PRMT4 inhibitors spanning both the substrate and the cosubstrate pockets. The reanalysis of the data suggested a PRMT7 preferential binding for shorter derivatives and prompted us to extend these structural studies to PRMT9. Here, we report the identification of the first potent PRMT7/9 inhibitor and its binding mode to the two PRMT enzymes. Label-free quantification mass spectrometry confirmed significant inhibition of PRMT activity in cells. We also report the setup of an effective AlphaLISA assay to screen small molecule inhibitors of PRMT9.

Turning Nonselective Inhibitors of Type I Protein Arginine Methyltransferases into Potent and Selective Inhibitors of Protein Arginine Methyltransferase 4 through a Deconstruction-Reconstruction and Fragment-Growing Approach

Protein arginine methyltransferases (PRMTs) are important therapeutic targets, playing a crucial role in the regulation of many cellular processes and being linked to many diseases. Yet, there is still much to be understood regarding their functions and the biological pathways in which they are involved, as well as on the structural requirements that could drive the development of selective modulators of PRMT activity. Here we report a deconstruction–reconstruction approach that, starting from a series of type I PRMT inhibitors previously identified by us, allowed for the identification of potent and selective inhibitors of PRMT4, which regardless of the low cell permeability show an evident reduction of arginine methylation levels in MCF7 cells and a marked reduction of proliferation. We also report crystal structures with various PRMTs supporting the observed specificity and selectivity.

Aortic valve replacement and coronary artery surgery: determinants affecting early and long-term results

BACKGROUND

We studied factors influencing early and late results in patients operated on for aortic valve replacement and coronary artery bypass graft.

METHODS

175 patients were retrospectively analysed over a 10-year period ending in December 2002. There were 135 males and 40 females with a mean age of 62.7 +/- 8.9 years; 109 were in NYHA class III/IV; 45 required an urgent operation, and 103 mechanical valves and 72 biological valves were implanted.

RESULTS

There were 11 operative deaths (6.3 %). Statistical analysis (logistic regression) showed that previous myocardial infarction, poor NYHA class, and low LVEF had a significant effect on early death. There were 52 late deaths at a mean follow-up of 82.7 +/- 38.8 months. Using a Cox survival analysis for any causes, age, urgent operation, low LVEF, and creatinine had a strong impact on unfavourable late outcome.

CONCLUSIONS

A combination of a patient-related factor (age), cardiac-related condition (low LVEF), co-morbid condition (renal dysfunction), and operative cause (urgent operation) is the most important predictor of late clinical outcome for this combined surgical procedure.

Endovascular Stent Grafts as a Safe Secondary Option for Paraanastomotic Abdominal Aortic Aneurysm

OBJECTIVE

To describe our experience of endovascular repair of para-anastomotic aortic aneurysm.

METHODS AND RESULTS

From March 2001 to December 2004 we identified 6 patients with a para-anastomotic aortic aneurysms following previous open repair of abdominal aortic aneurysm. All patients were treated with endovascular surgery under epidural anaesthesia. There were no major complications, surgical conversions or deaths. Four patients received a bifurcated aortic stent-graft, and two an aorto-uniliac stent-graft followed by a femoro-femoral bypass. At follow-up (mean 26.1+/-10.2 months) there were no deaths, endoleaks or graft migrations observed.

CONCLUSION

Endovascular surgery, avoiding general anesthesia and re-laparotomy, is the ideal technique for treatment of this complication resulting from failed primary conventional AAA repair.

Endovascular vs. Open Surgery of Abdominal Aortic Aneurysm in High-Risk Patients: A Single Center Experience

BACKGROUND

We compared two groups of high-risk patients with abdominal aortic aneurysm to assess the safety and efficacy of endovascular repair vs. open surgery.

METHODS

From January 1998 to July 2003, sixty-two high-risk patients were divided into two groups: group A consisted of 28 (46 %) open surgery patients and group B consisted of 34 (54 %) patients who underwent endovascular repair.

RESULTS

Four patients (14.3 %) in the open surgery group died, while no deaths occurred in the endovascular group ( p < 0.05). There were 14 complications in 8 patients of the open surgery group versus 2 complications in 2 patients of the endovascular group ( p = 0.01). At follow-up there were 4 (16.6 %) deaths in group A and 3 (8.8 %) in the endovascular group ( p = n. s.).

CONCLUSIONS

While the use of endovascular repair in patients who are physiologically fit for open surgical repair remains controversial, we believe that patients with multiple or advanced comorbidities, i.e. high-risk patients, can benefit from the endografting procedure.

Clinical outcome for on-pump myocardial revascularization in patients with mild renal dysfunction

BACKGROUND

Coronary artery disease is the major cause of death in patients with chronic renal failure. We studied the early and long-term outcome of patients with mild chronic renal impairment, preoperative regular diuresis, and normal potassium levels having undergone pump myocardial revascularization.

METHODS

From January 1992 to December 2000, 67 patients with serum creatinine level higher than 1.7 mg/dl and less than 2.5 mg/dl underwent on-pump myocardial revascularization. The patients were divided into 2 groups and treated with renal doses of dopamine in the postoperative or preoperative period, respectively. A homogeneous group of 100 patients was selected as control.

RESULTS

There were no statistically significant differences in mortality and morbidity between the two groups A, while there was a significant difference in cardiac and respiratory complications, ICU stay and LOS between the A and B group in the early and long-term follow-up. Survival at 12-year follow-up is significantly higher in the B group.

CONCLUSIONS

Patients with relatively mild renal insufficiency should be evaluated carefully for open cardiac surgery due to the significant increase in early and long-term morbidity and mortality.

Detection of postoperative pseudoaneurysms following abdominal aortic aneurysm repair in Behçet's disease by MRA

We report the development of two anastomotic pseudoaneurysms in a patient with Behçet's disease eighteen months after abdominal aortic aneurysm repair. Major asymptomatic vascular complications should be suspected in patients with Behçet's disease with a history of vascular surgery and treated expediently due to the risk of rupture. Magnetic resonance angiography, contrast-enhanced computed tomography or ultrasound scanning should be performed at least every 6 months after vascular surgery.

One-stage coronary and abdominal aortic operation with or without cardiopulmonary bypass: early and midterm follow-up

BACKGROUND

The aim of this study was to compare hospital, early, and late clinical outcomes for patients undergoing one-stage, coronary and abdominal aortic surgical intervention with and without cardiopulmonary bypass.

METHODS

From March 1990 to September 1999, 42 consecutive patients underwent combined operations at a single institution. Cardiopulmonary bypass and cardioplegic arrest were used during coronary revascularization in the first 20 patients (on-pump group), and the next 22 patients received the one-stage operations on the beating heart (off-pump group).

RESULTS

Baseline characteristics were similar between groups. Three cardiac-related hospital deaths occurred in the on-pump group and one such death in the off-pump group (p = 0.25). Cardiac-related events, pulmonary complications, inotropic support, blood loss and transfusion requirements, intensive care unit stay, and hospital stay were significantly reduced in the off-pump group (all, p < 0.05). The actuarial survival rates in the on-pump and off-pump groups were 80% and 95%, respectively, at 1 year (p = 0.13) and 75% and 89%, respectively, at 3 years (p = 0.22). Freedom from cardiac-related events at 1-year follow-up was 91% in the off-pump group and 65% in the on-pump group (p < 0.05). No difference in cardiac-related events between groups was observed at 3 years.

CONCLUSIONS

Off-pump coronary surgical procedures decrease postoperative complications in high-risk patients undergoing simultaneous coronary and abdominal aortic operations compared with the conventional one-stage procedure. The early benefits achieved with off-pump surgical intervention are not at the expense of the long-term clinical outcome.

Combined coronary artery and abdominal aortic surgery without cardiopulmonary bypass

To determine the effects of beating heart surgery on patients undergoing simultaneous coronary artery bypass grafting and abdominal aortic surgery, we performed such surgery on 20 patients (mean age, 64.55+/-796 SD years). Abdominal aortic disease was defined as an abdominal aortic aneurysm larger than 5 cm in diameter or as end-stage aortic occlusive disease. Hemodynamic measurements, inotropic requirements, and incidence of perioperative myocardial infarction and arrhythmias were recorded, as were subsystem clinical outcomes, length of intensive care unit and hospital stays, blood loss, and transfusion requirements. There was no incidence of death, perioperative myocardial infarction, stroke, or acute renal failure. The mean number of grafts per patient was 1.95+/-0.69. Only 4 minor postoperative complications were observed: three patients (15%) had evidence of supraventricular tachyarrhythmias, and 1 patient (5%) had chest infection that required a longer-than-average intubation period. Six patients (30%) required minimal-to-moderate inotropic support. The mean blood loss was 673+/-246.8 mL and transfusion requirements were low. The mean intensive care unit and hospital lengths of stay were 2. 12+/-0.33 days and 708+/-1.44 days, respectively. Clinical follow-up (mean, 10 months) showed all patients to be in New York Heart Association functional class I or II with no late cardiac or abdominal events. We conclude that simultaneous coronary artery bypass grafting and abdominal aortic surgery on the beating heart is safe and effective, and has a low perioperative clinical morbidity rate. To our knowledge, ours is the 1st report on this procedure. Larger studies with longer follow-up are needed.

Determinants of aortic artifacts during transesophageal echocardiography of the ascending aorta

BACKGROUND

The origin of artifacts of the ascending aorta during transesophageal echocardiography has not been widely studied. This study was undertaken to investigate in vivo whether anatomic features could determine the appearance of artifacts.

METHODS AND RESULTS

Transesophageal echocardiograms of 46 patients studied for suspected dissection with proven diagnosis (30 patients with and 16 without ascending aortic dissection) were reviewed. The incidence of artifacts was 46%, and it was similar in patients with and those without dissection (chi-square 0.516; P = not significant). Artifacts were located in the aortic lumen twice as far from the transducer as the atrial-aortic interface. The aortic diameter was larger in patients with than in those without artifacts (6.4 +/- 1.1 vs 4.2 +/- 0.9 cm, P <.001). An aortic diameter >5 cm and an atrial-aortic ratio </=0.6 predicted the artifact appearance with good sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy; these parameters reached a value of 100% by analysis only of patients without dissection.

CONCLUSIONS

An ascending aortic diameter >5.0 cm that exceeds the left atrial diameter with an atrial-aortic ratio </=0.6 creates in vivo the conditions for the reverberation of the atrial-aortic interface within the aorta. Therefore, in patients with such anatomic features, artifacts must be suspected in the presence of linear structures within the aorta.

Aortic valve replacement through a minimally invasive approach

Minimally invasive cardiac surgery is rapidly gaining interest because of fast recovery, reduced morbidity, shorter hospital stay, lower costs, and better cosmetic results. Aortic valve surgery can be performed through a small (10- to 12-cm) transverse sternal incision, and femoro-femoral cannulation is used for cardiopulmonary bypass. Exposure of the ascending aorta is satisfactory. From 1 March through 30 September 1996, 7 patients underwent aortic valve replacement through this approach. The mean age of the 5 women and 2 men was 58.8 years. We used this technique mainly in patients with chronic obstructive pulmonary disease, diabetes, or obesity, in the absence of coronary artery disease. There was no mortality, nor was there reoperation for bleeding, stroke, or wound infection. All patients were extubated after 2 hours in intensive care and were discharged on the 4th postoperative day. Additional cases are needed to properly assess the correct indication and surgical technique.

Electrodiagnostic testing in back and extremity pain

OBJECTIVE

The usefulness of electrodiagnostic testing by the primary care provider is shown in two cases of suspected compression-type neural lesions of the lumbar spine.

CLINICAL FEATURES

A 54-yr-old female with acute lumbar spine pain that radiated into the hip and a 26-yr-old male with sharp gluteal pain that radiated into the thigh and ankle were admitted into an inpatient care facility for intensive therapy. Plain film radiographs were obtained initially. In addition, electrodiagnostic testing was performed to evaluate the L5 and S1 nerve roots, which suggested compressive-type lesions. Non-enhanced CT of the lumbar spine was performed and revealed central disk herniation or protrusion in each case.

INTERVENTION AND OUTCOME

One patient exhibiting central compression signs of bladder dysfunction was referred for medical intervention. The remaining patient received flexion-distraction type of chiropractic manipulation with physiologic therapeutics and was discharged to outpatient care after 16 days.

CONCLUSIONS

Electrodiagnostic testing can provide the primary care provider the data needed to make an informed decision regarding advanced imaging studies and to institute appropriate therapy or to intelligently refer a patient for follow-up.