ITPA polymorphisms do not predict additional risk beyond TPMT and NUDT15 for thiopurine-induced cytopenia in inflammatory bowel disease

INTRODUCTION AND AIM

Thiopurine-related leukopenia is associated with polymorphisms in the thiopurine methyltransferase (TPMT) and nucleoside diphosphate-linked moiety X type motif 15 (NUDT15) genes. However, those polymorphisms explain only a fraction of thiopurine-related leukopenia. Our aim was to study the role of an inosine triphosphate pyrophosphatase (ITPA) polymorphism in patients with inflammatory bowel disease (IBD) and thiopurine-related leukopenia that was unexplained by the TPMT and NUDT15 polymorphisms.

MATERIAL AND METHODS

We enrolled consecutive IBD patients on thiopurines (azathioprine or 6-mercaptopurine) from January 2019-March 2020, at a tertiary care center in North India. The presence of the ITPA (C.94C > A) polymorphism was evaluated in all patients, along with its association with thiopurine-related leukopenia.

RESULTS

Of the 33 patients (from a total of 119 patients) that developed leukopenia, 8 had the TPMT (n = 1) or NUDT15 (n = 7) polymorphism. Of the remaining 111 patients, their mean age was 36.36 ± 13.54 years and 57 (51.3%) were males. Twenty-five (21.01%) had unexplained leukopenia. The ITPA polymorphism was detected in 4 (16%) patients in the unexplained leukopenia group and 24 (27.9%) patients in the non-leukopenia group (p = 0.228). The odds ratio for predicting leukopenia with the ITPA polymorphism was 0.4921 (95% CI 0.1520-1.5830, p = 0.234).

CONCLUSION

The ITPA (C.94C > A) polymorphism was frequently detected in the study population but was not predictive for leukopenia in patients with IBD on thiopurine therapy.

Directing group assisted para-selective C-H alkynylation of unbiased arenes enabled by rhodium catalysis

Regioselective C-H alkynylation of arenes via C-H activation is challenging yet a highly desirable transformation. In this regard, directing group assisted C(sp2)-H alkynylation of arenes offers a unique opportunity to ensure precise regioselectivity. While the existing methods are mainly centered around ortho-C-H alkynylation and a few for meta-C-H alkynylation, the DG-assisted para-selective C-H alkynylation is yet to be reported. Herein we disclose the first report on Rh-catalyzed para-C-H alkynylation of sterically and electronically unbiased arenes. The para-selectivity is achieved with the assistance of a cyano-based directing template and the selectivity remained unaltered irrespective of the steric and electronic influence of the substituents. The post-synthetic modification of synthesized para-alkynylated arenes is also demonstrated. The mechanistic intricacies of the developed protocol are elucidated through experimental and computational studies.

Emergence of Pyrimidine-Based meta-Directing Group: Journey from Weak to Strong Coordination in Diversifying meta-C-H Functionalization

C-H activation has emerged as a powerful transformative synthetic tool to construct complex molecular frameworks, which are ubiquitous in natural products, medicines, dyes, polymers, and many more. However, reactivity and selectivity, arising from the inertness of C-H bonds and their overabundance in organic molecules, are the two major fundamental challenges in developing various carbon-carbon (C-C) and carbon-heteroatom (C-X) bond formation reactions via C-H activation technique. Functional groups with coordinating capacity to the transition metal catalysts, profoundly known as directing groups (DGs), have shown great promise in exerting selective C-H activation, often called site-selective or regioselective transformation of a target molecule. Advent of directing group (DG)-assisted strategies not only has resolved the selectivity issues but also offers a unique solution to the rapid synthesis of complex molecules in a convenient and predictable manner. Our laboratory, in this regard, is fascinated by the prospect of DG-assisted distal C-H functionalization of arenes, in which the target C-H bond is remotely located from the existing directing group. Notably, in opposition to proximal ortho-C-H activation, which proceeded via an energetically favorable five- to seven-membered metallacycle, distal C-H activation remained a formidable challenge as it required formation of a large macrocyclic metallacycle. Therefore, designing a suitable directing template that would maintain the required distance and geometric relationship between the target C-H bond and the appended directing auxiliary in order to ensure the prolific delivery of the metal catalyst to the closest proximity of targeted distal C-H bond was the key to success. In this regard, the Yu group devised an elegant "U-shaped" template for the first time to execute distal meta-C-H activation recruiting a cyano-based directing group. Our initial effort to diversify the scope of meta-C-H functionalization using a cyano-based template led us to realize that the "cyano-based DGs" are intrinsically limited with weak coordinating ability, competitive binding mode (end-on vs side-on), and incompatibility with acidic and basic reaction conditions. In search of a robust directing auxiliary, we were intrigued by the possibility of using the strongly coordinating ability of pyrimidine and quinoline-based DGs.In this Account, we describe our journey from the weakly coordinating cyano-based DG to the strongly coordinating pyrimidine-based DG to achieve diverse meta-C-H functionalization of electronically and sterically unbiased arenes. While some of the functionalizations were achieved by finding suitable reaction conditions, others were led by mechanistic understanding. Notably, initial development in this realm was constrained with short linkers, in which the DG was attached to the arene of interest through 2-4 atoms. In later studies, we demonstrated that the selective meta-C-H activation can be attained even though the DG is 10-atoms away from the targeted arene. More importantly, a transient DG was successfully utilized to deliver meta-C-H olefination of arenes via in situ imine formation, which provided a step-economic route to meta-C-H activation.We hope that this Account will stimulate further template design and will provide a guiding platform for the future development of distal meta-C-H functionalization.

Directing Group Assisted Rhodium Catalyzed meta-CH Alkynylation of Arenes

Site-selective C-H alkynylation of arenes to produce aryl alkynes is a highly desirable transformation due to its prevalence in various natural products, drug molecules and in material sciences. To ensure...

Endovascular and percutaneous transabdominal embolisation of pseudoaneurysms in pancreatitis: an experience from a tertiary-care referral centre

AIM

To analyse the technical challenges, clinical success, and associated complications of endovascular and percutaneous embolisation of pancreatitis-related pseudoaneurysms.

MATERIALS AND METHODS

A retrospective study of patients referred for embolisation of pancreatitis-related pseudoaneurysms between January 2014 and March 2019 was conducted. Computed tomography angiography (CTA) was performed to assess the morphology of the aneurysms prior to any intervention. Percutaneous or endovascular embolisation was performed. Details of CTA and methods of embolisation were recorded. Technical success, clinical success, and complications were reported.

RESULTS

A total of 80 patients (mean age, 40.69 ± 13.41 years, 73 male) underwent embolisation during the study period. Pseudoaneurysms were related to chronic pancreatitis (CP) in 44 (55%) patients and acute pancreatitis (AP) in 36 (45%) patients. Pseudoaneurysms were detected in 65 (81.2%) patients on CTA. The most common site of pseudoaneurysms was gastroduodenal artery (GDA) followed by splenic artery. Seven patients were treated with percutaneous thrombin injection and five were treated with percutaneous glue injection under ultrasound/fluoroscopy guidance. The remaining patients (n=68) underwent catheter angiography with endovascular embolisation. Technical success was achieved in 4/7 (57%) percutaneous thrombin cases and in all the cases (5/5, 100%) with percutaneous glue or endovascular (68/68,100%) embolisation.

CONCLUSION

Endovascular or percutaneous embolisation of pseudoaneurysms has high technical success with an excellent safety profile.

Variability of contrast enhancement of pancreas on computed tomography in patients with acute pancreatitis and isolated extrapancreatic necrosis

BACKGROUND AND STUDY AIM

To evaluate the variability in the enhancement of pancreas on computed tomography (CT) in patients with acute pancreatitis (AP) and isolated extrapancreatic necrosis (EPN) and to investigate whether it affects the extrapancreatic findings and patient outcomes.

PATIENTS AND METHODS

This retrospective study comprised of consecutive patients with isolated EPN evaluated between April 2017 and April 2019. A radiologist measured the pancreatic attenuation values (PAV) of head, body, and tail on a contrast enhanced CT. Using a cut-off PAV of 100HU, patients were divided into two groups. The extrapancreatic CT findings and outcome parameters were compared between the two groups.

RESULTS

Thirty patients (mean age, 42.13 years, 17 males) with isolated EPN were evaluated. The mean PAV in the head, body, and tail was 83.13 HU (range, 59-161), 84.17 HU (range, 60-160), and 82.23 HU (range, 53-137). The overall mean PAV was 83.12 HU (range, 58-152). There were six patients with overall mean PAV≥100 HU. The group with PAV≥100 HU had a higher number of patients with infected necrosis (66.6% vs. 14.2%, P=0.018). PAV had a significant association with length of hospitalization (P=0.045).

CONCLUSION

There is significant variability in the pancreatic enhancement on CT among patients with AP and isolated EPN. Patients with PAV≥100 HU had a significantly longer hospital stay. This, however, may be related to a greater number of patients with infected necrosis in this group.

para-Selective Arylation of Arenes: A Direct Route to Biaryls by Norbornene Relay Palladation

Biaryl compounds are extremely important structural motifs in natural products, biologically active components and pharmaceuticals. Selective synthesis of biaryls by distinguishing the subtle reactivity difference of distal arene C-H bonds are significantly challenging. Herein, we describe para-selective C-H arylation, which is acheived by a unique combination of a meta-directing group and norbornene as a transient mediator. Upon direct meta-C-H palladation, one-bond relay palladation occurs in presence of norbornene and subsequently para-C-H arylation is achieved for sulfonates, phosphonates and phenols bearing 2,6-disubstitution patterns. The protocol is amenable to electron-deficient aryl iodides. Multisubstituted arenes and phenols are obtained by postsynthetic modification of the products. The protocol allows the synthesis of hexa-substituted benzene by sequential selective distal C-H functionalization.

Para-Selective Cyanation of Arenes by H-Bonded Template

The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work, we demonstrate the para-selective introduction of versatile nitrile moiety, enabled by a detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias. The conspicuous shift in the step energetics was probed by both experimental and computational mechanistic tools, which heralds the inception of para-deuteration. The synthetic impact of the methodology was highlighted with reusability of directing group and post synthetic modifications.

Role of computed tomography in prediction of gastrointestinal fistula in patients with acute pancreatitis

AIM

To identify computed tomography (CT) features that predict gastrointestinal fistula (GIF) in patients with acute pancreatitis (AP).

METHODS

This retrospective study comprised consecutive patients with AP and GIF from June 2017 to June 2018. The diagnosis of GIF was based on upper gastrointestinal endoscopy, colonoscopy or surgery. A cohort of 19 matched patients from a prospective database of AP served as control group. Measures of severity, and clinical outcome were evaluated. CT parameters were compared between the groups to assess the features that could predict the development of GIF.

RESULTS

There was no difference between the two groups in terms of disease etiology, severity, drainage, and mortality. On univariate analysis, the CT features that were found to be significantly different between the two groups were the presence of bowel wall thickening (P=0.005), maximum thickness of the bowel wall (P=0.007), presence of air foci in extra pancreatic necrosis/ collection (P=0.013), discontinuity of the bowel wall (P=0.046) and the displacement/ compression of bowel by fluid collection (P=0.014). On multivariate analysis, all the above-mentioned CT findings except discontinuity of bowel wall were found to be statistically significant.

CONCLUSION

CT is helpful in predicting GIF in patients with AP.

Rhodium catalyzed template-assisted distal para-C-H olefination

We report first example of template assisted rhodium catalyzed para-C–H alkenylation.

Rhodium catalysis has been extensively used for ortho-C–H functionalization reactions, and successfully extended to meta-C–H functionalization. Its application to para-C–H activation remains an unmet challenge. Herein we disclose the first example of such a reaction, with the Rh-catalyzed para-C–H olefination of arenes. The use of a Si-linked cyanobiphenyl unit as a traceless directing group leads to highly para-selective arene–olefin couplings.

Phosphine catalysed (5 + 1) annulation of ynone/cinnamates with primary amines

The (5 + 1) annulation of ynone/cinnamates with protected primary amines gives rise to various heterocycles in good to excellent yields under phosphine catalysis.

Antigenaemia and antibody response to Toxoplasma gondii in human immunodeficiency virus-infected patients

Toxoplasma encephalitis in immunocompromised patients results from reactivation of previously acquired (latent) infection. The aim of the study is to assess the antigenaemia and antibody response to Toxoplasma gondii in human immunodeficiency virus (HIV)-infected patients to determine the best marker for early diagnosis of toxoplasmosis in such patients. Indirect enzyme-linked immunosorbent assay (ELISA) for detection of IgG, IgM and IgA anti-toxoplasma antibodies and double-sandwich ELISA for toxoplasma antigen is carried out in serum samples collected from 100 HIV seropositive patients and 75 controls. Toxoplasma-specific IgG, IgM and IgA antibody response and antigenaemia were detected in 12%, 6%, 7% and 14% of HIV-infected patients, respectively. On retrospective analysis of 14 patients with antigenaemia only one had central nervous system (CNS) symptoms attributable to toxoplasma infection. In this patient, the CD4+ cell count was below 50/microL and none of the specific immunoglobulin isotype responses could be detected. The patient showed clinical improvement following specific chemotherapy for toxoplasmosis. In 25 HIV-negative and anti-toxoplasma IgG antibody-positive controls, IgM was detected in two (8%), IgA in five (20%) and antigenaemia in 10 (40%), while 50 HIV seronegative healthy controls were negative for both antigen and antibody responses. The study indicates that detection of toxoplasma antigen in addition to IgG antibody response may prove to be a useful indicator in the early diagnosis of reactivated toxoplasmosis in HIV/AIDS patients.

Aryl Nitriles from Alkynes Using tert-Butyl Nitrite: Metal-Free Approach to C≡C Bond Cleavage

Alkyne C≡C bond breaking, outside of alkyne metathesis, remains an underdeveloped area in reaction discovery. Recently, nitrogenation has been reported to allow nitrile formation from alkynes. A new protocol for the metal-free C≡C bond cleavage of terminal alkynes to produce nitriles is reported. This method provides an opportunity to synthesize a vast range of nitriles containing aryl, heteroaryl, and natural product derivatives (38 examples). In addition, the potential of (t)BuONO to act as a powerful nitrogenating agent for terminal aryl alkynes is demonstrated.

Remote para-C-H Functionalization of Arenes by a D-Shaped Biphenyl Template-Based Assembly

Site-selective C-H functionalization has emerged as an efficient tool in simplifying the synthesis of complex molecules. Most often, directing group (DG)-assisted metallacycle formation serves as an efficient strategy to ensure promising regioselectivity. A wide variety of ortho- and meta-C-H functionalizations stand as examples in this regard. Yet despite this significant progress, DG-assisted selective para-C-H functionalization in arenes has remained unexplored, mainly because it involves the formation of a geometrically constrained metallacyclic transition state. Here we report an easily recyclable, novel Si-containing biphenyl-based template that directs efficient functionalization of the distal p-C-H bond of toluene by forming a D-shaped assembly. This DG allows the required flexibility to support the formation of an oversized pre-transition state. By overcoming electronic and steric bias, para-olefination and acetoxylation were successfully performed while undermining o- and m-C-H activation. The applicability of this D-shaped biphenyl template-based strategy is demonstrated by synthesizing various complex molecules.

The regioselective iodination of quinolines, quinolones, pyridones, pyridines and uracil

A radical based direct C–H iodination protocol for quinolines, quinolones, pyridones, pyridines, and uracil has been developed.

High prevalence of human papillomavirus in esophageal squamous cell carcinoma: a study in paired samples

Esophageal squamous cell carcinoma (ESCC) is one of the common cancers with a poor prognosis. Incidences of human papillomavirus (HPV) infection range from 0 to 67% in different parts of the world. It has been frequently associated with high-risk HPV genotypes 16 and 18. The present study analyzes the prevalence of HPV infection in ESCC tumor and adjoining mucosa. Fresh tissue samples were obtained from ESCC tumor (group I) and adjoining mucosa (group II). Aliquots of DNA extracts were used. There were 23 patients with paired samples, 19 (83%) were male. HPV was positive in 20/23 (87%). Mean age of HPV positive in group I was 56.63 ± 6.96 and in group II 54.31 ± 7.13 years (P > 0.05). Majority had more than one viral type. HPV52 was the most common observed in 14 (61%) males and two (9%) females. Other common viruses were HPV55, 39, and 59. Smoking had a significant association with viral positivity. p63 and p16 oncoproteins correlated with degree of tumor differentiation but not with viral status. We documented high prevalence of high-risk HPV in ESCC. Our observations support the concept of persistent infection by an oncogenic HPV in cancer development. Our study highlights importance of documenting viral genotype in a defined geographic area.

The 9p24.3 breakpoint of a constitutional t(6;9)(p12;p24) in a patient with chronic lymphocytic leukemia maps close to the putative promoter region of the DMRT2 gene

B-cell chronic lymphocytic leukemia (B-CLL) is a very common hematological malignancy. Although several alterations in different loci have been identified and established as prognostic factors the pathogenetic cascade remains obscure. Here we give an account on a 71-year-old man with B-CLL and a translocation t(6;9) in his diagnostic bone marrow. Subsequent chromosome analysis of his blood lymphocytes revealed a constitutional karyotype 46,XY,t(6;9) (p12;p24) that has not been previously reported. Seeking for gene disruption correlated with the B-CLL we precisely mapped both breakpoints by fluorescence in situ hybridization (FISH) analysis with chromosome-specific bacterial artificial chromosome (BAC) clones and their long-range polymerase chain reaction (LRPCR) subfragments. An 11-kb LRPCR subfragment derived from RP11-399A15 was found to span the breakpoint at 6p12.1. FISH analysis with a 12-kb LRPCR fragment derived from RP11-147I11 which overlaps with RP11-110M16 as well as with a cDNA for DMRT2 (doublesex and mab-3 related transcription factor 2) maps the 9p24.3 breakpoint maximum 10 kb upstream from DMRT2. In silico analysis of the transcripts within the vicinity of the breakpoints revealed that the translocation does not disrupt any known genes but could affect the putative DMRT2 promoter. Long range effects on gene expression cannot be excluded so far.

Spermatheca Gland Extract of Snail (Telescopium telescopium) Has Wound Healing Potential: An Experimental Study in Rabbits

The effects of spermatheca gland extract of snail ( Telescopium telescopium) to promote wound healing were studied in an animal model. The spermatheca gland extract of the snail was used as a topical medicament to treat experimentally created full thickness wounds in 12 rabbits ( Oryctologous cuniculus). Wound healing was assessed on the basis of physical, histomorphological, and histochemical changes on days 0, 3, 7, and 14. Statistically significant differences were observed between the groups in all measured parameters. These exciting findings suggest that the data should be further tested in animal models to better understand the potential for wound healing in the spermatheca gland extract of the marine snail.

Wandering spleen presenting as bleeding gastric varices

Ectopic spleen (splenoptosis) is an extremely rare condition in which the spleen is present in a nonanatomical position. Patients' symptomatology is variable and ranges from mere feeling of an abdominal lump to sudden abdominal pain due to infarction. Patient may have subacute to chronic abdominal or gastrointestinal complaints. Because of nonspecific symptoms, clinical diagnosis can be difficult; hence, imaging plays an important role. Presentation as a case of portal hypertension is extremely rare. We report a case of splenic torsion in a middle-aged woman who presented with hemetemesis from gastric varices secondary to chronic volvulus of an ectopic spleen. Preoperative diagnosis was made on the basis of ultrasonography, endoscopy, and computed tomography, which was later proved on surgery and treated successfully.

Patients with gallstones develop gallbladder cancer at an earlier age

Significant proportions of Indian patients with gallbladder cancer are young. Multiple risk factors for gallbladder cancer are recognized among Indian patients. The effect of these risk factors on the age of development of gallbladder cancer is not known. We conducted a study to determine the influence of risk factors on the age at diagnosis of patients with gallbladder cancer and to assess the interactions between these risk factors. Patients with gallbladder cancer from two tertiary care institutions during the period 1994-2001 were prospectively studied. An ultrasound examination was done to look for the presence of gallstones. The influence of gender, gallstones, socio-economic status, smoking, residence in rural areas and in the Gangetic belt on the age at presentation was analysed using univariate analysis, logistic and linear regression analyses. The mean age of the 121 patients studied was 55+/-11.7 (SD) years. There were 51 (42%) patients aged less than 50 years. The younger patients (age < or =50 years) were more likely to have gallstones (88 versus 66%; P=0.008) and to have come from a lower socio-economic background (88 versus 71%; P=0.02) in comparison with older patients. However, there was no effect of the other risk factors. The independent determinants for younger age of patients with gallbladder cancer on logistic regression analysis were gallstones [odds ratio (OR) 4, 95% confidence interval (CI) 1.5-11; P=0.006] and lower socio-economic status (OR 3.1, 95% CI 1.1-8.6; P=0.03). On linear regression analysis, age at presentation was lowered by 5.6 years if there were associated gallstones. The mean age of patients with these two risk factors was significantly lower than that of those with one risk factor or no risk factor (52+/-12 years versus 57+/-11 years versus 61+/-9 years; P=0.007). In conclusion, the presence of gallstones and lower socio-economic status were both independently associated with a younger age at diagnosis of gallbladder cancer and their effect was additive.

Severe acute bleeding from portal colopathy controlled by somatostatin: a case report

Portal hypertensive colopathy (PHC) is a recently described entity in patients with portal hypertension which can cause even life-threatening lower gastrointestinal bleeding. In contrast to variceal bleed, there is no standardized treatment for the control of bleeding from these lesions. We report a case of alcoholic cirrhosis with portal hypertension, in whom bleeding from colonic angiodysplasia-like lesions was effectively controlled by somatostatin infusion.