Author Correction: Complete biosynthesis of cannabinoids and their unnatural analogues in yeast.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Complete biosynthesis of cannabinoids and their unnatural analogues in yeast.

Cannabis sativa L. has been cultivated and used around the globe for its medicinal properties for millennia1. Some cannabinoids, the hallmark constituents of Cannabis, and their analogues have been investigated extensively for their potential medical applications2. Certain cannabinoid formulations have been approved as prescription drugs in several countries for the treatment of a range of human ailments3. However, the study and medicinal use of cannabinoids has been hampered by the legal scheduling of Cannabis, the low in planta abundances of nearly all of the dozens of known cannabinoids4, and their structural complexity, which limits bulk chemical synthesis. Here we report the complete biosynthesis of the major cannabinoids cannabigerolic acid, Δ9-tetrahydrocannabinolic acid, cannabidiolic acid, Δ9-tetrahydrocannabivarinic acid and cannabidivarinic acid in Saccharomyces cerevisiae, from the simple sugar galactose. To accomplish this, we engineered the native mevalonate pathway to provide a high flux of geranyl pyrophosphate and introduced a heterologous, multi-organism-derived hexanoyl-CoA biosynthetic pathway5. We also introduced the Cannabis genes that encode the enzymes involved in the biosynthesis of olivetolic acid6, as well as the gene for a previously undiscovered enzyme with geranylpyrophosphate:olivetolate geranyltransferase activity and the genes for corresponding cannabinoid synthases7,8. Furthermore, we established a biosynthetic approach that harnessed the promiscuity of several pathway genes to produce cannabinoid analogues. Feeding different fatty acids to our engineered strains yielded cannabinoid analogues with modifications in the part of the molecule that is known to alter receptor binding affinity and potency9. We also demonstrated that our biological system could be complemented by simple synthetic chemistry to further expand the accessible chemical space. Our work presents a platform for the production of natural and unnatural cannabinoids that will allow for more rigorous study of these compounds and could be used in the development of treatments for a variety of human health problems.

Optimizing the biosynthesis of oxygenated and acetylated Taxol precursors in Saccharomyces cerevisiae using advanced bioprocessing strategies.

Taxadien-5α-hydroxylase and taxadien-5α-ol O-acetyltransferase catalyze the oxidation of taxadiene to taxadien-5α-ol and subsequent acetylation to taxadien-5α-yl-acetate in the biosynthesis of the blockbuster anticancer drug, paclitaxel (Taxol®). Despite decades of research, the promiscuous and multispecific CYP725A4 enzyme remains a major bottleneck in microbial biosynthetic pathway development. In this study, an interdisciplinary approach was applied for the construction and optimization of the early pathway in Saccharomyces cerevisiae, across a range of bioreactor scales. High-throughput microscale optimization enhanced total oxygenated taxane titer to 39.0 ± 5.7 mg/L and total taxane product titers were comparable at micro and minibioreactor scale at 95.4 ± 18.0 and 98.9 mg/L, respectively. The introduction of pH control successfully mitigated a reduction of oxygenated taxane production, enhancing the potential taxadien-5α-ol isomer titer to 19.2 mg/L, comparable with the 23.8 ± 3.7 mg/L achieved at microscale. A combination of bioprocess optimization and increased gas chromatography-mass spectrometry resolution at 1 L bioreactor scale facilitated taxadien-5α-yl-acetate detection with a final titer of 3.7 mg/L. Total oxygenated taxane titers were improved 2.7-fold at this scale to 78 mg/L, the highest reported titer in yeast. Critical parameters affecting the productivity of the engineered strain were identified across a range of scales, providing a foundation for the development of robust integrated bioprocess control systems.

Diagnostic Yield of Bronchoalveolar Lavage in Immunocompromised Children.

Results from early studies in the diagnostic yield of bronchoalveolar lavage (BAL) in immunocompromised adults and children were variable. This prospective study aimed to determine the diagnostic yield of BALs in immunocompromised children over the first 18 months of service at a newly established children's hospital. Relationship between BAL results and changes in antimicrobial management was also studied. Twenty-one bronchoscopic BALs were performed on 18 children; 14 BALs (66.7%) yielded at least 1 pathogen and 7 (33.3%) yielded no pathogen. Two pathogens were found in 2 samples, and 1 pathogen was identified in 12 samples. Bacteria (n = 7 patients), viruses (n = 8 patients) and fungus (Pneumocycstis jirovecii in one patient) were yielded. Of the 21 BALs, 8 (38.1%) were associated with changes in antimicrobial management (Fisher's exact test, p = 0.018). No significant side effects such as pneumothorax or pulmonary hemorrhages were observed in this series. In conclusion, BAL in immunocompromised children is rewarding and has potential to impact on antimicrobial management.

Batch Versus Flow Lithiation-Substitution of 1,3,4-Oxadiazoles: Exploitation of Unstable Intermediates Using Flow Chemistry.

1,3,4-Oxadiazoles are a common motif in pharmaceutical chemistry, but few convenient methods for their modification exist. A fast, convenient, high yielding and general α-substitution of 1,3,4-oxadiazoles has been developed using a metalation-electrophilic trapping protocol both in batch and under continuous flow conditions in contradiction to previous reports which suggest that α-metalation of this ring system results in ring fragmentation. In batch, lithiation is accomplished at an industrially convenient temperature, -30 °C, with subsequent trapping giving isolated yields of up to 91 %. Under continuous flow conditions, metalation is carried out at room temperature, and subsequent in flow electrophilic trapping gave up to quantitative isolated yields. Notably, lithiation in batch at room temperature results only in ring fragmentation and we propose that the superior mixing in flow allows interception and exploitation of an unstable intermediate before decomposition can occur.

De novo synthesis of the sedative valerenic acid in Saccharomyces cerevisiae.

Valeriana officinalis (Valerian) root extracts have been used by European and Asian cultures for millennia for their anxiolytic and sedative properties. However, the efficacy of these extracts suffers from variable yields and composition, making these extracts a prime candidate for microbial production. Recently, valerenic acid, a C15 sesquiterpenoid, was identified as the active compound that modulates the GABAA channel. Although the first committed step, valerena-4,7(11)-diene synthase, has been identified and described, the complete valerenic acid biosynthetic pathway remains to be elucidated. Sequence homology and tissue-specific expression profiles of V. officinalis putative P450s led to the discovery of a V. officinalis valerena-4,7(11)-diene oxidase, VoCYP71DJ1, which required coexpression with a V. officinalis alcohol dehydrogenase and aldehyde dehydrogenase to complete valerenic acid biosynthesis in yeast. Further, we demonstrated the stable integration of all pathway enzymes in yeast, resulting in the production of 140 mg/L of valerena-4,7(11)-diene and 4 mg/L of valerenic acid in milliliter plates. These findings showcase Saccharomyces cerevisiae's potential as an expression platform for facilitating multiply-oxidized medicinal terpenoid pathway discovery, possibly paving the way for scale up and FDA approval of valerenic acid and other active compounds from plant-derived herbal medicines.

High-titer production of lathyrane diterpenoids from sugar by engineered Saccharomyces cerevisiae.

Euphorbiaceae are an important source of medically important diterpenoids, such as the anticancer drug ingenol-3-angelate and the antiretroviral drug prostratin. However, extraction from the genetically intractable natural producers is often limited by the small quantities produced, while the organic synthesis of terpene-derived drugs is challenging and similarly low-yielding. While transplanting the biosynthetic pathway into a heterologous host has proven successful for some drugs, it has been largely unsuccessful for diterpenoids due to their elaborate biosynthetic pathways and lack of genetic resources and tools for gene discovery. We engineered casbene precursor production in S. cerevisiae, verified the ability of six Euphorbia lathyris and Jatropha curcas cytochrome P450s to oxidize casbene, and optimized the expression of these P450s and an alcohol dehydrogenase to generate jolkinol C, achieving ~800mg/L of jolkinol C and over 1g/L total oxidized casbanes in millititer plates, the highest titer of oxidized diterpenes in yeast reported to date. This strain enables the semisynthesis of biologically active jolkinol C derivatives and will be an important tool in the elucidation of the biosynthetic pathways for ingenanes, tiglianes, and lathyranes. These findings demonstrate the ability of S. cerevisiae to produce oxidized drug precursors in quantities that are sufficient for drug development and pathway discovery.

Liver stiffness measurement by transient elastography as a predictor on posthepatectomy outcomes.

BACKGROUND: Liver fibrosis and cirrhosis are well-known risk factors for morbidity after hepatectomy. Liver stiffness measurement (LSM) using transient elastography is a new method for detection of hepatic fibrosis and cirrhosis with high accuracy. Whether LSM can predict posthepatectomy outcomes has not been studied. METHODS: This was a prospective cohort study in which consecutive patients underwent hepatectomy for various indications from February 2010 to July 2011. All patients received detailed preoperative assessments including LSM and indocyanine green (ICG) clearance test. The primary outcome was major postoperative complication. RESULTS: One hundred five patients with a mean age of 59 years were included; 75 (71.4%) had chronic viral hepatitis and 76 (72.4%) had hepatocellular carcinoma. Thirty-four patients (32.4%) received major hepatectomy. The median ICG retention rate at 15 minutes was 4.2 (0.1%-32%) and the median LSM was 9.4 (3.3-75 kPa). For posthepatectomy outcomes, only LSM but not ICG showed significant correlation with major postoperative complications on receiver operating characteristic curves, with area under the curve of 0.79 (P < 0.001). Using the calculated cutoff at 12.0 kPa, LSM had sensitivity of 85.7% and specificity of 71.8% in the prediction of major postoperative complications. It was also an independent prognostic factor for major postoperative complications by multivariate analysis. The operative blood loss and transfusion rate were also significantly higher in patients with LSM >12.0 kPa. CONCLUSIONS: High LSM (>12.0 kPa) predicted worse posthepatectomy outcomes. Preoperative LSM was better than ICG test in the prediction of major postoperative complications. It was a useful preoperative investigation for risk stratification before hepatectomy.

Thyroid Abscess: A Case Series and Literature Review.

OBJECTIVE: In this retrospective case series, we chronicle six patients presenting with acute suppurative thyroiditis (AST) with progression to thyroid abscess in a single institution. METHODS: Patients ranged in age from 16 to 74 years of age. The most common presenting symptoms were progressive unilateral neck pain, swelling, and odynophagia. Other symptoms included hoarseness and systemic signs of infection. Diagnosis of thyroid abscess was made with a CT scan of the neck, fine needle aspiration, and/or incision and drainage (I&D). RESULTS: Management included antibiotic therapy, I&D, and thyroidectomy. All patients were successfully treated except for one who developed mediastinitis and died. CONCLUSION: A complete literature review was performed to determine etiologies, common findings, and management of similar cases.

Impact of Giving Patients Your Personal Phone Number in Otolaryngology-Head & Neck Surgery.

OBJECTIVE: Patient-provider communication is a major barrier to care, with some providers giving their personal phone number (PPN) to patients for increased accessibility. We investigated participant utilization of provider's PPN, its effect on participant satisfaction, provider's ability to predict abuse of this practice, and evolving provider perceptions. STUDY DESIGN: Prospective, randomized study. SETTING: Single institution, tertiary referral center. METHODS: During a 2-week period, otolaryngology patients were randomized to either receive their provider's PPN or not. Providers predicted the likelihood of abuse. All calls/texts were documented for 4 weeks. At the study's conclusion, participants were surveyed using Press Ganey metrics. Providers were surveyed before and after to assess their likelihood of providing patients with their PPN and its impact on work demands. RESULTS: Of the 507 participants enrolled, 266 were randomized to the phone number group (+PN). Of 44 calls/texts from 24 participants, 8 were considered inappropriate. Ten participants were predicted to abuse the PPN, but only one was accurately identified. Participants in the +PN group had a greater mean composite satisfaction score than the control group (4.8 vs 4.3; Welch's t-test, P < .0011). At the conclusion of the study, providers were more likely to share their PPN (Wilcoxon signed-rank test, P < .0313), and their perceived impact of this practice on workload was lower (Wilcoxon signed-rank test, P < .0469). CONCLUSION: This study demonstrates low patient utilization of provider PPNs, and poor provider predictive ability of patient abuse. Receipt of provider's PPN was associated with improved patient satisfaction.

Pre-operative predictors of post-hepatectomy recurrence of hepatocellular carcinoma: can we predict earlier?

BACKGROUNDS AND PURPOSE: To determine the predictors for recurrence in patients receiving curative hepatectomy for hepatocellular carcinoma (HCC). METHODS: From January 2001 to July 2007, all patients having hepatectomy for first occurrence HCC with curative intent were identified from a prospectively collected database. Prognostic factors for recurrence and survival after resection were analyzed. RESULTS: A total of 235 patients were included. With a median follow-up of 50.2 (0.07-125.1) months, the recurrence rate was 57.0%. The 1-, 3-, and 5-year overall survival rates were 83.9%, 66.0%, and 58.1% respectively. Multivariate analysis demonstrated that multi-focal lesions (HR: 2.93, P < 0.001), alpha-fetoprotein (AFP) level greater than 100 ng/ml (HR: 1.74, P = 0.002) and history of tumor rupture (HR: 2.84, P = 0.003) were independent risk factors for recurrence of HCC after hepatectomy. CONCLUSIONS: Predictors for HCC recurrence can be identified before operation. These important parameters should be considered before and after contemplating curative resection for HCC patients and for risk stratification in future clinical trials for neoadjuvant or post-resection adjuvant therapy. The possible use of neoadjuvant or adjuvant treatment to improve survival should be addressed by further trials.

Surgical ablation of hepatocellular carcinoma with 2.45-GHz microwave: a critical appraisal of treatment outcomes.

OBJECTIVE: To evaluate the efficacy and safety of a new generation of 2.45-GHz microwave to ablate hepatocellular carcinoma by surgical approach. DESIGN; Case series with prospective follow-up. SETTING: A university teaching hospital in Hong Kong. PATIENTS: From March 2009 to January 2011, 26 consecutive patients (19 men and 7 women) with a median age of 63 (range, 49-79) years with hepatocellular carcinoma were recruited. Five (19%) of the patients had recurrent hepatocellular carcinoma after previous treatment. INTERVENTION: Microwave ablation for hepatocellular carcinomas (one tumour, n=24; two tumours, n=2) using a laparoscopic (n=16) or open approach (n=10). MAIN OUTCOME MEASURES: Operative mortality and morbidity, rate of incomplete ablation, recurrence rate, and survival rate. RESULTS: The median tumour diameter was 3.8 cm (range, 2.0-6.0 cm). Complications occurred in five (19%) of the patients; only one was ablation-related, and there was no operative mortality. One (4%) of the patients experienced incomplete ablation. Recurrent tumours were noted in 11 (42%) of the patients (5 were local, 2 were remote, and 4 were multifocal) after a median follow-up of 14 (range, 4-26) months. The failure rate for local disease control was 23%, and was 14% if patients with recurrent hepatocellular carcinoma were excluded. All but one patient survived until the time of censorship. The mean survival was 25 (standard deviation, 1) months. CONCLUSION: This new-generation microwave technique is safe and effective for local ablation of hepatocellular carcinoma. It is a valuable treatment option for patients who are not candidates for hepatectomy.

Prostate Cancer Characteristics and Outcomes after Prostatectomy in Asian-American Men.

BACKGROUND: Prostate cancer is the most commonly diagnosed cancer in American men, with striking differences between ethnic groups. Given the potential for lifestyle or genetic variations between subsets of Asian-American men to impact prostate cancer behavior, we sought to define the outcomes after radical prostatectomy among various Asian groups treated at an NCI-designated comprehensive cancer center. METHODS: The City of Hope IRB-approved prostatectomy database was searched from 2003 to 2015 to identify Asian-American men. Clinical and pathologic features were collected and analyzed for association with biochemical recurrence-free survival and overall survival (OS). Categorical data were evaluated using χ2and Fisher's exact tests. Survival curves were compared between groups using log-rank testing. RESULTS: Three hundred and eighty-three Asian-American men were included in the dataset. While Asian men as a group had lower BMI than African-American and white men in the database, there was a wide range between ethnic sub-groups. Chinese men more commonly presented with D'Amico low risk disease features (P= .04) compared to other Asian men. Pacific Islander men had the lowest rate of ≥T3 stage and the highest biochemical recurrence-free survival. OS for Chinese men was better than for all Asian patients combined (P= .046). After controlling for D'Amico risk and in multivariate analysis, Chinese men still had improved OS than other Asian men after prostatectomy (P= .03). CONCLUSIONS: Asian-American men have differing prostate cancer characteristics. Future efforts to delineate and impact upon prostate cancer outcomes should categorize Asian men by subgroup in order to better elucidate biology, lifestyle factors and/or treatment preferences that may contribute to observed differences.

Immune Reconstitution following High-Dose Chemotherapy and Autologous Stem Cell Transplantation with or without Pembrolizumab Maintenance Therapy in Patients with Lymphoma.

Autologous stem cell transplantation (ASCT) is a standard of care for patients with chemosensitive, relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and diffuse large B cell lymphoma (DLBCL). Whereas the clinical benefit of ASCT has traditionally been attributed solely to cytoreduction from intensive chemotherapy, ASCT has important immunogenic effects that may contribute to its antitumor efficacy and could provide a favorable immune environment for post-ASCT immune-based maintenance treatments. We previously reported clinical results of a phase II trial (ClinicalTrials.gov identifier NCT02362997) testing 8 doses of pembrolizumab maintenance therapy after ASCT for patients with R/R cHL or DLBCL. To clarify the impact of pembrolizumab on immune reconstitution, we compared the kinetics of peripheral blood immune cell recovery after ASCT for trial patients receiving pembrolizumab maintenance to those of a contemporaneous control cohort of similar patients undergoing ASCT without pembrolizumab maintenance. This study was conducted to characterize the impact of post-ASCT pembrolizumab maintenance therapy on immune reconstitution for patients with R/R DLBCL and cHL and to identify candidate biomarkers of efficacy and immune-related adverse events (irAEs). Peripheral blood (PB) mononuclear cell samples were prospectively collected at 1 to 18 months after ASCT and analyzed by flow cytometry using a panel of fluorophore-conjugated monoclonal antibodies to identify B cells, natural killer (NK) cells, and various dendritic cell (DC) and T cell subsets. A median of 5 (range, 1 to 8) post-ASCT PB samples were collected from 144 patients (59 in the pembrolizumab group and 85 in the control group). Clinical characteristics of the 2 cohorts were similar. Compared with cHL patients, DLBCL patients (all of whom received anti-CD20 monoclonal antibody therapy before ASCT) had delayed CD19+ cell reconstitution that persisted for at least 18 months after ASCT. No other differences in immune reconstitution based on lymphoma subtype were observed. Post-ASCT pembrolizumab maintenance therapy was associated with an elevation in circulating DCs (driven by higher levels of plasmacytoid and immature DCs) that persisted for the duration of pembrolizumab treatment, along with a significant reduction in PD-1+ T cells that persisted for 6 to 12 months after completion of pembrolizumab therapy. Despite the key role of T cells in mediating the effects of PD-1 blockade, pembrolizumab maintenance did not affect recovery of any T cell subsets. In an exploratory analysis, a higher baseline CD4+ terminal effector memory cell count (defined as CD3+CD4+CD45RA+CD62L-) was associated with inferior progression-free survival (PFS), but only among patients who received pembrolizumab maintenance (P = .003). As continuous variables, lower absolute levels of NK cells (P = .009), PD-1+ CD4+ T cells (P = .005), and PD-1+ CD8+ T cells (P = .005) before pembrolizumab initiation were each associated with a higher risk of grade 2+ irAEs. Our findings indicate that post-ACST pembrolizumab maintenance therapy is associated with a persistent elevation of circulating DCs, but its impact on the reconstitution of other immune cells in peripheral blood appears limited. Our study suggests that early features of post-ASCT immune reconstitution could be associated with PFS and the risk of irAE and warrant additional investigation. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Long-term results of laparoscopic hepatectomy versus open hepatectomy for hepatocellular carcinoma: a case-matched analysis.

BACKGROUND: Laparoscopic hepatectomy (LH) is established as a safe and feasible treatment option for liver tumors. However, whether the adoption of laparoscopic approach for malignant tumors, such as hepatocellular carcinoma (HCC), will compromise the long-term result is still unknown. This study was designed to evaluate the long-term results of LH compared with a cohort of case-matched open hepatectomy (OH). METHODS: Thirty-three patients who underwent LH for HCC in our institution between June 2004 and March 2010 were recruited. A group of 50 patients who underwent OH for HCC during the same period was identified by matching to magnitude of operation, size of tumor, site of tumor, and the absence of concomitant local ablation or major procedure. The perioperative outcomes, disease recurrence, and survival of the two groups of patients were determined and compared. RESULTS: LH resulted in less operative complications (6.1% vs. 24%, P = 0.033) and shorter median hospital stay (5 vs. 7 days, P < 0.0005) but required longer operative time compared with OH (225 vs. 195 min, P = 0.019). There was no difference between LH and OH in recurrence rate (45.5% vs. 38%, P = 0.499). The 1-, 3-, and 5-year overall survival were 86.9%, 81.8%, and 76% for LH and 98%, 80.6%, and 76.1% for OH respectively (P = 0.646). The 1-, 3-, and 5-year disease-free survival were 78.8%, 51%, and 45.3% for LH and 69.2%, 55.9%, and 55.9% for OH, respectively (P = 0.849). CONCLUSIONS: Compared with OH, LH for HCC has similar long-term outcomes, but it has short-term advantages of less operative complications and shorter hospital stay.

Single-incision laparoscopic cholecystectomy: from four wounds to one.

OBJECTIVE: To review the initial results and surgical outcomes of single-incision laparoscopic cholecystectomy. DESIGN: Prospective case series. SETTING: A university teaching hospital and a regional hospital in Hong Kong. PATIENTS: All patients undergoing single-incision laparoscopic cholecystectomy from August 2009 to March 2011. RESULTS: Fifty patients underwent single-incision laparoscopic cholecystectomy during the study period. The indications for surgery included symptomatic gallstones (n=43) and gallbladder polyps (n=7). The mean operating time was 78 (standard deviation, 24) minutes. Forty-five of the patients successfully underwent single-incision laparoscopic cholecystectomy, giving a success rate of 90%. In the remaining five patients, additional working ports were constructed to obtain better exposure and dissection around Calot's triangle. On comparing the results of the initial 25 cases to the subsequent 25 cases, in the latter group the operating time was significantly shorter (86 vs 71 minutes; P=0.02), and the success rate was higher (80% vs 100%; P=0.05). During the median follow-up period of 6.8 months, four patients had complications, which included: postoperative urinary retention (n=2), one each with a haematoma and an incisional hernia. No patient endured bile duct injury, postoperative bile leakage, or haemorrhage in our series. CONCLUSION: Single-incision laparoscopic cholecystectomy is feasible and safe for treatment of uncomplicated gallbladder diseases. There was a reduction in the operating time and increase in success rate with accumulation of experience. Nevertheless, surgeons should be cautious about the potential risks of this new technique.

Modification of right hepatectomy results in improvement outcome: a retrospective comparative study.

OBJECTIVE: To evaluate any change in the operative and survival outcomes in patients undergoing a right hepatectomy after adoption of the no-clamp technique using a radiofrequency dissecting sealer (TissueLink™) in liver resection. METHODS: In all, 58 consecutive patients who underwent a right hepatectomy from July 2003 to December 2007 (Group 1) were compared with 66 consecutive patients who underwent a right hepatectomy from January 1999 to June 2003 (Group 2). In group 1, a liver transection was performed with a cavitron ultrasonic surgical aspirator (CUSA) and TissueLink™ without hilar clamping whereas in group 2, a liver transection was performed with CUSA and diathermy with routine continuous hilar clamping. RESULTS: For the operative outcomes, there was significantly less blood loss (median 450 vs. 900 ml, P < 0.001) in group 1. The complication rate was also significantly lower in group 1 (22.4% vs. 47.0%, P = 0.004). In subgroup analysis for patients with hepatocellular carcinoma (HCC), the overall survival rate was significantly better in group 1; 1-, 3- and 5-year survival rates were 78%, 72% and 57% in group 1 vs. 72%, 44% and 39% in group 2, respectively (P = 0.048). CONCLUSIONS: When compared with the retrospective cohort, a right hepatectomy utilizing TissueLink™ without hilar clamping was feasible with potential benefits in surgical outcomes.

Flash chemistry enables high productivity metalation-substitution of 5-alkyltetrazoles.

Tetrazoles play a prominent role in medicinal chemistry due to their role as carboxylate bioisosteres but have largely been overlooked as C-H functionalisation substrates. We herein report the development of a high-yielding and general procedure for the heterobenzylic C-H functionalisation of 5-alkyltetrazoles in up to 97% yield under batch conditions using a metalation/electrophilic trapping strategy. Through the use of thermal imaging to identify potentially unsafe exotherms, a continuous flow procedure using a flash chemistry strategy has also been developed, allowing products to be accessed in up to 95% yield. This enabled an extremely high productivity rate of 141 g h-1 to be achieved on an entry-level flow system.

Resection margin in laparoscopic hepatectomy: a comparative study between wedge resection and anatomic left lateral sectionectomy.

BACKGROUND: Experience from open hepatectomy shows that anatomic liver resection achieves a better resection margin than wedge resection. In recent years, laparoscopic hepatectomy has increasingly been performed in patients with liver pathology including malignant lesions. Wedge resection (WR) and left lateral sectionectomy (LLS), which also represent non-anatomic and anatomic resection respectively, are the two most common types of laparoscopic hepatectomy performed. The aim of the present study was to compare the two types of laparoscopic hepatectomy with emphasis on resection margin. METHODS: Between November 2003 and July 2009, 44 consecutive patients who underwent laparoscopic hepatectomy were identified and retrospectively reviewed. The WR and LLS group of patients were compared in terms of operative outcomes, pathological findings, recurrence patterns and survival. RESULTS: Out of the 44 patients, 21 underwent LLS and 23 a WR. The two groups of patients were comparable in demographics. The two groups did not differ in conversion rate, blood loss, blood transfusion, mortality, morbidity and post-operative length of stay. The LLS group patients had significantly larger liver lesions, wider resection margin and less sub-centimetre margins. In patients with malignant liver lesions, there was no difference between the two groups in incidence of intra-hepatic recurrence and 3-year overall and disease-free survival. CONCLUSION: Operative outcomes are similar between laparoscopic WR and LLS. However, WR is less reliable than LLS in achieving a resection margin of more than 1 cm. Larger studies involving more patients with longer follow-up are warranted to determine the impact of the resection margin on intra-hepatic recurrence and survival.

Lithiation Substitution of Unprotected Benzyltetrazoles.

1H-Tetrazoles occupy an important role in modern medicinal chemistry, but few methods for their modification exist. Many extant protocols require the use of a difficult to remove N-alkyl-protecting group, precluding the products from use as carboxylate bioisosteres, the major role of tetrazoles in pharmaceuticals. We herein report a convenient, protecting-group-free lithiation-substitution protocol for benzylic tetrazoles. Metalation with n-BuLi at 0 °C followed by electrophilic trapping gave a range of α-functionalized benzyltetrazoles in up to 91% yield.