Beta-Blocker and Calcium Channel Blocker Toxicity With BRASH Syndrome: A Case Report.

Atrioventricular (AV) nodal blockers have a wide variety of medical uses, including the management of hypertension and cardiac arrhythmias. Like any other drug, they can carry side effects and toxicity. We present a case of a patient with a constellation of findings consistent with bradycardia, renal failure, AV nodal blockade, shock, and hyperkalemia (BRASH) syndrome. A 75-year-old female with a history of paroxysmal atrial fibrillation and heart failure with preserved ejection fraction presented to the hospital with shortness of breath. She was discharged two weeks prior to the presentation from another hospital after being treated for atrial fibrillation with a rapid ventricular response. She was discharged on metoprolol and diltiazem. Upon presentation to the hospital, the patient was noted to be bradycardic and hypotensive with blood work notable for acute kidney injury and hyperkalemia, consistent with BRASH syndrome. She received a dose of intravenous (IV) glucagon followed by infusion and received epinephrine infusion. Once clinically stable, she was discharged with her home dose of metoprolol and a reduced dose of diltiazem with a close follow-up with cardiology. Early recognition of BRASH syndrome as a unique clinical entity rather than different pathologic conditions is important to improve morbidity and mortality in these patients.

Malignant gastrointestinal neuroectodermal tumor-A case report.

Malignant gastrointestinal neuroectodermal tumor (GNET) is a rare neoplasm with unknown etiology. It was previously referred to as Clear cell sarcoma of gastrointestinal tract. This tumor is characterized by a higher rate of local recurrence and metastasis. Due to its aggressive clinical course, distinguishing this entity from various other mimickers is very essential. Herein, we present a case of malignant GNET in a 33-year-old male patient.

Chemoport Insertion-Less Is More.

Implantable chemoport is a very useful device for long-term venous access for infusion of chemotherapeutic drugs and other agents. There are few studies from resource poor countries reporting complications of chemoport. The aim of the present study is to evaluate the feasibility of chemoport insertion without image guidance and by closed technique without direct visualisation of a major vein (mainly IJV) and to study the complications associated with the procedure. This was a prospective observational study which analysed 263 patients who underwent chemoport insertion. The medical records of these patients were analysed for the patient characteristics, diagnosis, port-related complications, and their management. A total of 263 patients who were harbouring either locoregionally advanced or metastatic tumour requiring either chemotherapy or targeted treatment or both were included in the study. In total, 133 (50.57%) were female patients and 130 were male patients (49.43%). A total of 236 patients (89.73%) underwent port insertion procedures under local anaesthesia. None of the patients had any major intra-operative complications. Postoperatively, 4 patients (1.52%) were found to have port catheter malposition; 3 out of this 4 were corrected under IITV guidance as a second procedure under local anaesthesia only. One patient (0.38%) required formal removal and replacement of port. Four patients (1.52%) developed IJV thrombosis requiring port removal and anti-coagulation. One patient (0.38%) developed thrombus in the right atrium. There were 2 port site infections (0.74%) requiring port removal (SSI cat. 5). Low complication rates of port insertion were observed in the present, large, prospective study. Complication rates may be further reduced by using a well-designed procedure, experienced surgeons, an aseptic environment, ultrasound-guided puncture, and fluoroscopy with contrast media. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13193-020-01265-6.

Novel, Selective Inhibitors of USP7 Uncover Multiple Mechanisms of Antitumor Activity In Vitro and In Vivo.

The deubiquitinase USP7 regulates the levels of multiple proteins with roles in cancer progression and immune response. Thus, USP7 inhibition may decrease oncogene function, increase tumor suppressor function, and sensitize tumors to DNA-damaging agents. We have discovered a novel chemical series that potently and selectively inhibits USP7 in biochemical and cellular assays. Our inhibitors reduce the viability of multiple TP53 wild-type cell lines, including several hematologic cancer and MYCN-amplified neuroblastoma cell lines, as well as a subset of TP53-mutant cell lines in vitro Our work suggests that USP7 inhibitors upregulate transcription of genes normally silenced by the epigenetic repressor complex, polycomb repressive complex 2 (PRC2), and potentiate the activity of PIM and PI3K inhibitors as well as DNA-damaging agents. Furthermore, oral administration of USP7 inhibitors inhibits MM.1S (multiple myeloma; TP53 wild type) and H526 (small cell lung cancer; TP53 mutant) tumor growth in vivo Our work confirms that USP7 is a promising, pharmacologically tractable target for the treatment of cancer.

Discovery of Potent, Selective, and Orally Bioavailable Inhibitors of USP7 with In Vivo Antitumor Activity.

USP7 is a promising target for cancer therapy as its inhibition is expected to decrease function of oncogenes, increase tumor suppressor function, and enhance immune function. Using a structure-based drug design strategy, a new class of reversible USP7 inhibitors has been identified that is highly potent in biochemical and cellular assays and extremely selective for USP7 over other deubiquitinases. The succinimide was identified as a key potency-driving motif, forming two strong hydrogen bonds to the allosteric pocket of USP7. Redesign of an initial benzofuran-amide scaffold yielded a simplified ether series of inhibitors, utilizing acyclic conformational control to achieve proper amine placement. Further improvements were realized upon replacing the ether-linked amines with carbon-linked morpholines, a modification motivated by free energy perturbation (FEP+) calculations. This led to the discovery of compound 41, a highly potent, selective, and orally bioavailable USP7 inhibitor. In xenograft studies, compound 41 demonstrated tumor growth inhibition in both p53 wildtype and p53 mutant cancer cell lines, demonstrating that USP7 inhibitors can suppress tumor growth through multiple different pathways.

Male Breast Cancer: Current Trends-a Tertiary Care Centre Experience.

Male breast cancer is a rare tumour in all parts of the world. About 1% of all breast cancers occur in men. Occurrence of male breast cancer peaks at age 71 years. Familial cases usually have BRCA2 rather than BRCA1 mutations. Presentation is usually a lump or nipple inversion, but is often late, with more than 40% of individuals having stage III or IV disease. We retrospectively reviewed 25 male patients with breast cancer who came to the HCG Cancer Centre, Ahmedabad between 2014 and 2018, and their demographic details, tumor profile, and radiological, histopathological as well as luminal profile findings were studied. The average age at presentation and detection of male breast cancer was 61.08 years. Incidence of male ca. breast over these 4 years was 4.75/year which had a significant increase compared with our own data in the last 8 years (3/year). Male to female ratio for ca. breast was 1:61. One out of 25 (4%) patients had gynaecomastia. The most common histology was invasive ductal carcinoma-not otherwise specified with none of the patients having lobular carcinoma. Majority of patients were ER/PR positive and HER-2 negative. Male breast cancer is having a rising incidence, which in our study is 1.56%. Males have relatively older age at presentation and stage-by-stage treatment remains the same. Males are more likely to be having prognostically favourable luminal subtypes. Male breast cancer in Indian population is currently experiencing an increasing trend. Improved awareness amongst patients and high index of suspicion by the clinicians along with accurate diagnostic techniques help detect the disease at an earlier stage culminating into prolonged overall and disease-free survival.

Munc18a does not alter fusion rates mediated by neuronal SNAREs, synaptotagmin, and complexin.

Sec1/Munc18 (SM) proteins are essential for membrane trafficking, but their molecular mechanism remains unclear. Using a single vesicle-vesicle content-mixing assay with reconstituted neuronal SNAREs, synaptotagmin-1, and complexin-1, we show that the neuronal SM protein Munc18a/nSec1 has no effect on the intrinsic kinetics of both spontaneous fusion and Ca(2+)-triggered fusion between vesicles that mimic synaptic vesicles and the plasma membrane. However, wild type Munc18a reduced vesicle association ∼50% when the vesicles bearing the t-SNAREs syntaxin-1A and SNAP-25 were preincubated with Munc18 for 30 min. Single molecule experiments with labeled SNAP-25 indicate that the reduction of vesicle association is a consequence of sequestration of syntaxin-1A by Munc18a and subsequent release of SNAP-25 (i.e. Munc18a captures syntaxin-1A via its high affinity interaction). Moreover, a phosphorylation mimic mutant of Munc18a with reduced affinity to syntaxin-1A results in less reduction of vesicle association. In summary, Munc18a does not directly affect fusion, although it has an effect on the t-SNARE complex, depending on the presence of other factors and experimental conditions. Our results suggest that Munc18a primarily acts at the prefusion stage.

Three αSNAP and 10 ATP molecules are used in SNARE complex disassembly by N-ethylmaleimide-sensitive factor (NSF).

The fusion of intracellular membranes is driven by the formation of a highly stable four-helix bundle of SNARE proteins embedded in the vesicle and target membranes. N-Ethylmaleimide sensitive factor recycles SNAREs after fusion by binding to the SNARE complex through an adaptor protein, αSNAP, and using the energy of ATP hydrolysis to disassemble the complex. Although only a single molecule of αSNAP binds to a soluble form of the SNARE complex, we find that three molecules of αSNAP are used for SNARE complex disassembly. We describe an engineered αSNAP trimer that supports more efficient SNARE complex disassembly than monomeric αSNAP. Using the trimerized αSNAP, we find that N-ethylmaleimide-sensitive factor hydrolyzes 10 ATP molecules on average to disassemble a single SNARE complex.

The Toxoplasma pseudokinase ROP5 is an allosteric inhibitor of the immunity-related GTPases.

The Red Queen hypothesis proposes that there is an evolutionary arms race between host and pathogen. One possible example of such a phenomenon could be the recently discovered interaction between host defense proteins known as immunity-related GTPases (IRGs) and a family of rhoptry pseudokinases (ROP5) expressed by the protozoan parasite, Toxoplasma gondii. Mouse IRGs are encoded by an extensive and rapidly evolving family of over 20 genes. Similarly, the ROP5 family is highly polymorphic and consists of 4-10 genes, depending on the strain of Toxoplasma. IRGs are known to be avidly bound and functionally inactivated by ROP5 proteins, but the molecular basis of this interaction/inactivation has not previously been known. Here we show that ROP5 uses a highly polymorphic surface to bind adjacent to the nucleotide-binding domain of an IRG and that this produces a profound allosteric change in the IRG structure. This has two dramatic effects: 1) it prevents oligomerization of the IRG, and 2) it alters the orientation of two threonine residues that are targeted by the Toxoplasma Ser/Thr kinases, ROP17 and ROP18. ROP5s are highly specific in the IRGs that they will bind, and the fact that it is the most highly polymorphic surface of ROP5 that binds the IRG strongly supports the notion that these two protein families are co-evolving in a way predicted by the Red Queen hypothesis.

Structural basis of GSK-3 inhibition by N-terminal phosphorylation and by the Wnt receptor LRP6.

Glycogen synthase kinase-3 (GSK-3) is a key regulator of many cellular signaling pathways. Unlike most kinases, GSK-3 is controlled by inhibition rather than by specific activation. In the insulin and several other signaling pathways, phosphorylation of a serine present in a conserved sequence near the amino terminus of GSK-3 generates an auto-inhibitory peptide. In contrast, Wnt/ß-catenin signal transduction requires phosphorylation of Ser/Pro rich sequences present in the Wnt co-receptors LRP5/6, and these motifs inhibit GSK-3 activity. We present crystal structures of GSK-3 bound to its phosphorylated N-terminus and to two of the phosphorylated LRP6 motifs. A conserved loop unique to GSK-3 undergoes a dramatic conformational change that clamps the bound pseudo-substrate peptides, and reveals the mechanism of primed substrate recognition. The structures rationalize target sequence preferences and suggest avenues for the design of inhibitors selective for a subset of pathways regulated by GSK-3. DOI: http://dx.doi.org/10.7554/eLife.01998.001.

Hypofractionated image-guided radiation therapy for patients with limited volume metastatic non-small cell lung cancer.

INTRODUCTION: Outcomes data treating patients with oligometastatic (≤ 5 metastases) non-small cell lung carcinoma (NSCLC) with hypofractionated image-guided radiotherapy (HIGRT) are limited. METHODS: Consecutive oligometastatic NSCLC patients were reviewed from a prospective database. Patients were included if all active diseases were treated with HIGRT. Lesions that had received prior radiation or had radiographic/metabolic resolution after chemotherapy were not treated with HIGRT. Local control of all treated lesions, distant control, progression-free survival (PFS), overall survival (OS), and control of individual lesions (LeC) were calculated. RESULTS: Twenty-five patients with median of 2 treated oligometastatic lesions were included. Median follow-up was 14 months. Median age was 66 years. Nineteen patients received systemic therapy before HIGRT and 11 had progressive disease after their most recent systemic therapy before HIGRT. Median OS and PFS were 22.7 and 7.6 months. The 18 months local control, distant control, OS, and PFS were 66.1%, 31.7%, 52.9%, and 28.0%. Greater than two sites treated with HIGRT, nonadenocarcinoma histology, prior systemic therapy, and progression after systemic therapy were associated with worse PFS. Sixty-two individual lesions of median size 2.7 cm were treated. For extracranial lesions, median total and fraction dose were 50 and 5 Gy. Median standard equivalent dose in 2 Gy fractions for extracranial lesions was 64.6 Gy yielding 18 months LeC of 70.7%. Standard equivalent dose ≥64.6 Gy increased LeC (p = 0.04). Two patients experienced grade 3 toxicity. CONCLUSIONS: HIGRT for oligometastatic NSCLC provides durable LeC and may provide long-term PFS in some patients. Future HIGRT studies should optimize patient selection and integration with systemic therapy.

Golgi alpha-mannosidase II cleaves two sugars sequentially in the same catalytic site.

Golgi alpha-mannosidase II (GMII) is a key glycosyl hydrolase in the N-linked glycosylation pathway. It catalyzes the removal of two different mannosyl linkages of GlcNAcMan(5)GlcNAc(2), which is the committed step in complex N-glycan synthesis. Inhibition of this enzyme has shown promise in certain cancers in both laboratory and clinical settings. Here we present the high-resolution crystal structure of a nucleophile mutant of Drosophila melanogaster GMII (dGMII) bound to its natural oligosaccharide substrate and an oligosaccharide precursor as well as the structure of the unliganded mutant. These structures allow us to identify three sugar-binding subsites within the larger active site cleft. Our results allow for the formulation of the complete catalytic process of dGMII, which involves a specific order of bond cleavage, and a major substrate rearrangement in the active site. This process is likely conserved for all GMII enzymes-but not in the structurally related lysosomal mannosidase-and will form the basis for the design of specific inhibitors against GMII.

Comparison of kifunensine and 1-deoxymannojirimycin binding to class I and II alpha-mannosidases demonstrates different saccharide distortions in inverting and retaining catalytic mechanisms.

Mannosidases are key enzymes in the eukaryotic N-glycosylation pathway. These enzymes fall into two broad classes (I and II) and are characteristically different in catalytic mechanism, sequence, and structure. Kifunensine is an alkaloid that is a strong inhibitor against class I alpha-mannosidases but is only a weak inhibitor against class II alpha-mannosidases. In this paper, the 1.80 A resolution crystal structure of kifunensine bound to Drosophila melanogaster Golgi alpha-mannosidase II (dGMII) is presented. Kifunensine adopts a (1,4)B boat conformation in the class II dGMII, which contrasts the (1)C(4) chair conformation seen in class I human endoplasmic reticulum alpha1,2 mannosidase (hERMI, PDB ). The observed conformations are higher in conformational energy than the global minimum (4)C(1) conformation, although the conformation in hERMI is closer to the minimum, as supported by an energy calculation. Differing conformations of 1-deoxymannojirimycin were also observed: a (4)C(1) and (1)C(4) conformation in dGMII and hERMI, respectively. Thus, these two alpha-mannosidase classes distort these inhibitors in distinct manners. This is likely indicative of the binding characteristics of the two different catalytic mechanisms of these enzymes.