De novo loss-of-function variants in STAG2 are associated with developmental delay, microcephaly, and congenital anomalies

The cohesin complex is an evolutionarily conserved multi-subunit protein complex which regulates sister chromatid cohesion during mitosis and meiosis. Additionally, the cohesin complex regulates DNA replication, DNA repair, and transcription. The core of the complex consists of four subunits: SMC1A, SMC3, RAD21, and STAG1/2. Loss-of-function mutations in many of these proteins have been implicated in human developmental disorders collectively termed "cohesinopathies." Through clinical exome sequencing (CES) of an 8-year-old girl with a clinical history of global developmental delay, microcephaly, microtia with hearing loss, language delay, ADHD, and dysmorphic features, we describe a heterozygous de novo variant (c.205C>T; p.(Arg69*)) in the integral cohesin structural protein, STAG2. This variant is associated with decreased STAG2 protein expression. The analyses of metaphase spreads did not exhibit premature sister chromatid separation; however, delayed sister chromatid cohesion was observed. To further support the pathogenicity of STAG2 variants, we identified two additional female cases from the DECIPHER research database with mutations in STAG2 and phenotypes similar to our patient. Interestingly, the clinical features of these three cases are remarkably similar to those observed in other well-established cohesinopathies. Herein, we suggest that STAG2 is a dosage-sensitive gene and that heterozygous loss-of-function variants lead to a cohesinopathy.

Effect of Variable Oxidation States of Vanadium on the Structural, Optical, and Dielectric Properties of B2O3-Li2O-ZnO-V2O5 Glasses

In the present study, the effect of variable vanadium oxidation states on the structural, optical, and dielectric properties of vanadium oxide containing lithium borate glasses has been investigated. Electron paramagnetic resonance studies indicate that vanadium in these glasses is mostly in the V⁴⁺ state, having a tetragonal symmetry. As the glass composition of V₂O₅ increases, tetragonality also increases at the cost of octahedral symmetry. The photoluminescence (PL) spectra of these glasses are dominated by zinc oxide transition, whereas the peaks pertaining to the vanadyl group are not visible in the PL spectra. The optical absorption spectra show a single wide absorption band, which is attributed to V⁴⁺ ions in these glasses. The ac conductivity of the glasses increases with an increase in vanadium content. The highest electrical conductivity observed is ∼10^-5 S cm^-1 at 250 °C for the glass with 2.5 mol % V₂O₅. Electrical conductivity is dominated by electron conduction, as indicated by the activation energy calculation.

Mitochondrial dysfunction in cancer chemoprevention by phytochemicals from dietary and medicinal plants

Cancer chemoprevention, a scientific term coined by Dr. Sporn in the late seventies, implies use of natural or synthetic chemicals to block, delay or reverse carcinogenesis. Phytochemicals derived from edible and medicinal plants have been studied rather extensively for cancer chemoprevention using preclinical models in the past few decades. Nevertheless, some of these agents (e.g., isothiocyanates from cruciferous vegetables like broccoli and watercress) have already entered into clinical investigations. Examples of widely studied and highly promising phytochemicals from edible and medicinal plants include cruciferous vegetable constituents (phenethyl isothiocyanate, benzyl isothiocyanate, and sulforaphane), withaferin A (WA) derived from a medicinal plant (Withania somnifera) used heavily in Asia, and an oriental medicine plant component honokiol (HNK). An interesting feature of these structurally-diverse phytochemicals is that they target mitochondria to provoke cancer cell-selective death program. Mechanisms underlying cell death induction by commonly studied phytochemicals have been discussed rather extensively and thus are not covered in this review article. Instead, the primary focus of this perspective is to discuss experimental evidence pointing to mitochondrial dysfunction in cancer chemoprevention by promising phytochemicals.

Risk adapted single-agent dactinomycin or carboplatin for second-line treatment of methotrexate resistant low-risk gestational trophoblastic neoplasia

OBJECTIVE

To evaluate the outcome of patients treated with second-line chemotherapy for methotrexate-resistant low-risk GTN at the Sheffield Centre, UK between 2001 and 2015, including the novel use of single-agent carboplatin as a strategy to reduce exposure to combination chemotherapy.

METHODS

392 low-risk GTN patients were treated with first-line methotrexate. The selection of chemotherapy regimen following methotrexate-resistance depended on the volume of residual disease as indicated by the serum hCG value at the time, with patients switching to either single-agent dactinomycin at an hCG level<150IU/L from 2001-2010 and <300IU/L since 2010, or to combination treatment with etoposide/dactinomycin (EA) above these thresholds. In order to reduce exposure to more toxic combination chemotherapy regimens, our treatment policy was revised in 2011, with the recommendation of single-agent carboplatin as an alternative to EA at hCG levels >300IU/L.

RESULTS

136 (35%) of 392 received second-line chemotherapy following methotrexate-resistance. 59 patients received single-agent dactinomycin with 53 (90%) patients achieving complete hCG response, 3 patients requiring combination chemotherapy or surgery, and 3 patients subsequently spontaneously resolving. 56 patients received EA chemotherapy with hCG complete response in 50 (89%) patients, and the remaining 6 patients were cured with further multi-agent chemotherapy or surgery. With carboplatin, 17/21 (81%) achieved an overall complete hCG response rate, with 4 patients requiring third-line EA. Carboplatin was well tolerated with no significant alopecia; myelosuppression was the most significant toxicity. Overall survival for all patients was 100%.

CONCLUSION

These data show the continued excellent outcomes for methotrexate-resistant low-risk patients treated with single-agent dactinomycin or EA. Our experience with carboplatin is promising and provides an alternative regimen for methotrexate-resistant low-risk disease that avoids alopecia and in-patient treatment.

A Sensitive Triple Quadrupole Liquid Chromatography Mass Spectrometric Method for the Estimation of Valproic Acid in K2EDTA Human Plasma using Furosemide as the Internal Standard

A valproic acid is primarily being used in the treatment of epilepsy is a histone deacetylase inhibitor and it is under investigation for treatment of HIV and various cancer indications. A specific, sensitive and fast bioanalytical LC-MS/MS method was developed with furosemide as an internal standard (IS) and thoroughly validated for the quantitation of valproic acid using turbo ion spray in negative ion mode. The analyte and IS was extracted using protein precipitation. The chromatographic separation of analytes from extracted matrix was achieved using a Chromolith RP 18e (2.0×50 mm) column with a gradient mobile phase comprising of acetonitrile and purified water with acetic acid. The elution of both peaks was achieved within 5.2 min, with retention times of 2.55 min and 1.67 min for valproic acid and IS, respectively. Quantitation of valproic acid was achieved by the pseudo SRM transition pairs (m/z 142.8→m/z 142.8), and SRM transition pair (m/z 328.8 →m/z 204.6) for internal standard.The calibration standards of valproic acid showed linear over a range from 50 to 40 000 ng/mL, with a lower limit of quantitation of 50 ng/mL with accuracy of 3.74% and precision of 5.06%. The bias for inter- and intra-batch assays was 1.24-6.14% and 3.85-11.84%, respectively; while the corresponding precision was 2.56-16.37% and 1.29-11.34%, respectively. The developed method was used to monitor valproic acid levels in clinical samples. Because of higher sensitivity, this method can be used for therapeutic drug monitoring in pediatric subjects.

Perforations and fistulae in gastrointestinal tuberculosis

Background: Perforation and fistulae, though uncommon, are serious complications of gastrointestinal tuberculosis. Patients with acute tuberculous perforation are subjected to surgery, whereas localized perforation and fistulae with subtle clinical signs are detected by barium contrast examination. There has been no report on radiological series regarding the incidence of perforation and fistulae, detected by barium contrast studies.

Material and Methods: A retrospective analysis of barium contrast studies of 684 proven cases of gastrointestinal tuberculosis seen over a period of 15 years was done to detect the incidence of perforation and fistulae.

Results: Fifty-two patients (7.6%) with localized perforation and fistulae were seen. Twenty-eight patients had evidence of perforation, and 24 patients showed fistulae formation. The most common site of perforation and fistulae was the small bowel followed by the colon. Associated abnormalities noted were ulcerations, strictures, nodular filling defects and extrinsic compression.

Conclusion: Perforation and fistulae along with other associated abnormalities of the gastrointestinal tract are suggestive of tuberculosis, particularly in a population predisposed to tuberculous infection.

Imaging of esophageal tuberculosis: A review of 23 cases

Purpose: To evaluate the various radiological abnormalities in patients with proven esophageal tuberculosis.

Material and Methods: The case records of 23 patients with proven esophageal tuberculosis were evaluated retrospectively for various radiological abnormalities. Twenty-two patients had secondary involvement of esophagus in the form of direct extension of mediastinal and pulmonary tuberculosis or spinal tuberculosis. Only 1 patient had primary involvement of the esophagus with no evidence of disease elsewhere. The diagnosis was confirmed by endoscopic and CT-guided biopsy/aspiration cytology in 7 and 6 cases, respectively. Diagnosis was made on the basis of surgical biopsy of lymph node and autopsy in 1 patient each. In the remaining 8 patients the diagnosis was based on radiological and endoscopic findings and the response to antituberculous treatment.

Results: Chest radiography (CXR) was abnormal in 65% patients. While the findings were non-conclusive for esophageal tuberculosis, characteristic lesions of tuberculosis in lungs or spine were suggestive of tuberculous etiology. In 15 patients, CT of the chest confirmed the corresponding CXR findings and also showed additional findings of mediastinal lymphadenopathy when CXR was normal. Fourteen patients showed mediastinal lymphadenopathy on CT of the chest. In all these patients, more than one group of lymph nodes was involved. The characteristic hypodense center of lymph nodes suggestive of tuberculosis was seen in 12 patients. Radiological abnormalities seen in barium swallow examination were extrinsic compression, traction diverticula, strictures, sinus/fistulous tracts, kinking and pseudotumor mass of esophagus in decreasing order of frequency. The middle third of the esophagus was found to be the most frequent site of involvement.

Iodixanol in Abdominal Digital Subtraction Angiography

The safety, tolerability and efficacy of iodixanol 270 mg I/ml were compared to those of iohexol 300 mg I/ml in a double-blind, randomized, parallel abdominal intra-arterial DSA phase III trial. Fifty-nine patients were included in the trial; 39 patients received iodixanol and 20 received iohexol. The mean volume of iodixanol administered was 235.8 ml (0.93 g I/kg b.w.) while the mean volume of iohexol was 254.7 ml (1.10 g I/kg b.w.). No differences in diagnostic information and radiographic density were apparent in spite of the difference in the concentration of iodine. No serious adverse events occurred. Four patients (10%) in the iodixanol group and 2 (10%) in the iohexol group experienced adverse events. Eight percent of the injections of iodixanol promoted discomfort, compared to 12%) of the injections of iohexol. An increase in S-urea and S-creatinine was seen with both agents the first day after injection, but appeared to be less pronounced with iodixanol than with iohexol. Other serum tests revealed no changes of clinical importance. Both iodixanol and iohexol were found to be effective, safe and well tolerated contrast media for abdominal intra-arterial DSA.