Opioid-induced hypogonadism: Pathophysiology, clinical and therapeutics review.

Opioids are pivotal therapeutics in the management of escalated chronic pain (moderate-severe). In the last two decades, the increased prescription rate and the prolonged usage of opioids shed light on opioid-induced endocrinopathy. Opioid-induced hypogonadism (OHG) results upon long-term opioid therapy. Clinically, patients with OHG are presented mainly by sexual dysfunction and infertility. Opioid clinical use in pain therapy is indispensable. However, the resultant sexual endocrinopathy cannot be overlooked and hence hormonal replacement therapy with regular monitoring of the patients represents a potential therapeutic strategy while avoiding opioids in patients with guaranteed long therapeutic exposure and switching to using low-dose naltrexone as alternative represents a possible prophylactic measure to ensure therapeutic compliance and secure a good life quality of patients.

Benzimidazole derivatives as potential dual inhibitors for PARP-1 and DHODH.

Poly (ADP-ribose) polymerases (PARPs) play diverse roles in various cellular processes that involve DNA repair and programmed cell death. Amongst these polymerases is PARP-1 which is the key DNA damage-sensing enzyme that acts as an initiator for the DNA repair mechanism. Dihydroorotate dehydrogenase (DHODH) is an enzyme in the pyrimidine biosynthetic pathway which is an important target for anti-hyperproliferative and anti-inflammatory drug design. Since these enzymes share a common role in the DNA replication and repair mechanisms, it may be beneficial to target both PARP-1 and DHODH in attempts to design new anti-cancer agents. Benzimidazole derivatives have shown a wide variety of pharmacological activities including PARP and DHODH inhibition. We hereby report the design, synthesis and bioactivities of a series of benzimidazole derivatives as inhibitors of both the PARP-1 and DHODH enzymes.

Clinical usefulness of nebulized dexmedetomidine for conscious sedation in daycare flexible bronchoscopy in Southern India.

BACKGROUND: Sedative agents used in bronchoscopy require trained personnel to administer and monitor the patient. This increases the procedure cost, duration, and inpatient stay. Inhalational administration of sedative agents can be a practical solution to the issue. Dexmedetomidine in the inhalational form could give results similar to the intravenous form without significant adverse events. MATERIALS AND METHODS: The study is prospective, randomized, and double-blinded study. Patients needing bronchoscopy were randomized to receive the nebulized form of either dexmedetomidine or saline (0.9%) before bronchoscopy. The study parameters are assessed and recorded before, during, and after bronchoscopy. Data collected are analyzed using the SPSS software. DISCUSSION: The side effects limit using commonly administered sedation agents in bronchoscopy, such as midazolam, fentanyl, and dexmedetomidine. The nebulized dexmedetomidine is safe with proven efficacy when compared to the placebo. Proceduralist-administered conscious sedation reduces the overall cost and shortens inpatient stays. Attenuation of hemodynamic parameters by dexmedetomidine could be an advantage for the physician in reducing an untoward cardiac event. CONCLUSION: Dexmedetomidine in the nebulized form improves the comfort of patients during the procedure. It blunts the pressure response during bronchoscopy and could be a safer and cost-effective agent in its nebulized form for conscious sedation in bronchoscopy. The study is approved by the institutional ethics committee (IEC KMC MLR 10-2021-310).

RV in COPD - The complicated matters of the heart - Correlation of ECHO and biomarker with COPD severity and outcome.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) have an increased risk of cardiovascular involvement, which is among the leading causes of morbidity and mortality worldwide. Echocardiography (ECHO) could be a reliable, non-invasive tool for predicting the risk of cardiovascular modalities in patients with COPD. Combining the ECHO parameters with highly selective cardiac troponin could predict the severity and outcome of patients with COPD. METHODS: This prospective observational study was conducted at a tertiary care hospital in South India. All patients who met the criteria were included. Patients with other concomitant chronic lung diseases were excluded. An echocardiographic examination was performed, and blood samples for hs-Tnt were taken on admission for patients admitted with COPD. Categorical variables were analyzed using Pearson's Chi-square test, and the T-test was used to compare the means. One-way analysis of variance (ANOVA) followed by the Bonferroni multiple comparison tests was done to compare different echo parameters concerning COPD severity. RESULTS: The mean tricuspid annulus plane systolic excursion (TAPSE) and right ventricle (RV) fraction area change (FAC) values were lower with the increase in the disease severity (P < 0.001). There was a significant increase in the mean systolic pressures in the right atrium and ventricle in patients with severe COPD (P < 0.001). The mean hs-TnT values were significantly higher in patients with severe COPD (18.86 ± 18.12) and correlated well with the increase in the severity of the disease (P < 0.001). Changes in the echo parameters, such as mean TAPSE and RV FAC values, negatively correlated with COPD severity. There was an increase in systolic pressure in both atria and ventricles with the progression of COPD. Troponin helped predict mortality during hospitalization. CONCLUSION: Comprehensive echocardiographic parameters, such as TAPSE and RV FAC, help assess the disease's severity, predict mortality, and evaluate whether the proper ventricular function is reliable. Troponin is a valuable adjunct that is an independent and strong predictor of overall mortality in patients with COPD.

A silent march-Post covid fibrosis in asymptomatics - A cause for concern?

We report a case series of patients presenting with undiagnosed pulmonary fibrosis as a primary manifestation. On evaluation, after excluding other causes, the fibrosis was attributed to asymptomatic or mild COVID illness in the past. This case series serves to highlight the difficulties posed to clinicians while evaluating pulmonary fibrosis in the post-COVID era, more so in mild to asymptomatic COVID-19. The intriguing possibility of fibrosis setting even in mild to asymptomatic COVID is discussed.

Mental health and quality of life among patients with chronic respiratory failure on domiciliary oxygen: a prospective cohort study from a tertiary care centre in India.

OBJECTIVES: The study aims to assess the prevalence of anxiety, depression and the quality of life among patients with chronic respiratory failure and the changes in anxiety and depression scores after initiating domiciliary oxygen. DESIGN AND SETTING: Prospective, single-centre cohort study conducted in a tertiary care hospital in India. PARTICIPANTS: Patients of Indian origin with chronic respiratory failure who visited the hospital where domiciliary oxygen is indicated were included in the study. Patients with acute respiratory failure on a mechanical ventilator, haemodynamic instability and already-diagnosed psychiatric conditions were excluded from the study. INTERVENTIONS: Patients who met the inclusion criteria were assessed at baseline, at 3 and 6 months, for anxiety and depression using the 7-item Generalised Anxiety Disorder questionnaire (GAD-7) and 9-item Patient Health Questionnaire (PHQ-9). Quality of life was evaluated using the WHO Quality of Life-BREF questionnaire. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome is the proportion of patients with chronic respiratory failure having depression and anxiety and assessing the changes in anxiety and depression scores after initiating domiciliary oxygen. The secondary outcome is the change in health-related quality of life (HRQOL) of patients on domiciliary oxygen. RESULTS: 121 patients who met the inclusion criteria were included in the study. Of 102 patients who completed the study, 36.2% (n=37) had anxiety and 44.1% (n=45) had depression at baseline. There is a worsening trend in the mean GAD-7 (p=0.003) and PHQ-9 score (p=0.015) in patients over 6 months while on domiciliary oxygen. HRQOL is poor in all the domains at baseline, and there is a progressive worsening during follow-up while on oxygen. CONCLUSIONS: The worsening trend in anxiety and depression in patients after initiating domiciliary oxygen may be related to social isolation, restricted mobility, economic issues, addictions and frequency of exacerbations. Screening for psychological problems in these patients at baseline and on follow-ups helps early detection, and prompt intervention could improve the quality of life and survival.

Clinical usefulness of intermediate-dose dexmedetomidine (0.75 µg/kg) in flexible bronchoscopy - A prospective, randomized, double-blinded study.

BACKGROUND: Dexmedetomidine, although an effective drug for conscious sedation during flexible bronchoscopy, has occasional side effects on the cardiovascular system which need to be addressed. MATERIALS AND METHODS: Patients between 18 and 65 years, requiring diagnostic flexible bronchoscopy, found eligible, after screening, were randomized to either receive 0.75 µg/kg intravenous dexmedetomidine over 10 min or intravenous midazolam 0.035 mg/kg over 1 min. Composite score was used as the primary outcome measure. Additional parameters recorded were: Hemodynamic variables, oxygen saturation, Ramsay sedation score, for pain intensity and distress Numerical Rating Scale, number of rescue medication doses, ease of doing bronchoscopy, Visual Analog Scale score for cough and response of the patient 24 h after bronchoscopy. RESULTS: In each group, 24 patients were enrolled. The composite score was in the ideal category in 24 patients in dexmedetomidine group and 21 in midazolam group, at nasopharynx (P = 0.234). The corresponding values at the level of trachea were 23 and 16 (P = 0.023). In dexmedetomidine group, patient response after 24 h of bronchoscopy showed quality of sedation to be excellent in 0 subjects, good in 13, fair in 9 and poor in 2 and discomfort to be nil in 7, mild 10, moderate in 7 and severe in 0. The corresponding values in midazolam group for quality of sedation were 0, 4, 14, 6, and for discomfort 0, 10, 14, 0. The Visual Analog Scale (VAS) for cough revealed a mean score of 0.800 and 1.812 (P = 0.011) during and 2.092 and 3.542 (P = 0.016) 24 h after bronchoscopy in the respective study groups. CONCLUSION: Low-dose dexmedetomidine (0.75 µg/kg single dose) appears to provide better patient comfort and equivalent safety profile when compared with midazolam.

Structural and binding studies of cyclin-dependent kinase 2 with NU6140 inhibitor.

Cyclin-dependent kinase 2 (CDK2) is an established target protein for therapeutic intervention in various diseases, including cancer. Reported inhibitors of CDK2 target the ATP-binding pocket to inhibit the kinase activity. Many small molecule CDK2 inhibitors have been discovered, and their crystal structure with CDK2 or CDK2-cyclin A complex has been published. NU6140 is a CDK2 inhibitor with moderate potency and selectivity. Herein, we report the cocrystal structure determination of NU6140 in complex with CDK2 and confirmation of the binding using various biophysical methods. Our data show that NU6140 binds to CDK2 with a Kd of 800 nM as determined by SPR and stabilizes the protein against thermal denaturation (ΔTm -5°C). The cocrystal structure determined in our study shows that NU6140 binds in the ATP-binding pocket as expected for this class of compounds and interacts with Leu83 and Glu81 with regular hydrogen bonds and with Asp145 via water-mediated H-bond. Based on these data, we propose structural modifications of NU6140 to introduce new interactions with CDK2 that can improve its potency while retaining the selectivity.

Structure of cyclin-dependent kinase 2 (CDK2) in complex with the specific and potent inhibitor CVT-313.

CVT-313 is a potent CDK2 inhibitor that was identified by screening a purine-analogue library and is currently in preclinical studies. Since this molecule has the potential to be developed as a CDK2 inhibitor for cancer therapy, the potency of CVT-313 to bind and stabilize CDK2 was evaluated, together with its ability to inhibit aberrant cell proliferation. CVT-313 increased the melting temperature of CDK2 by 7°C in thermal stabilization studies, thus indicating its protein-stabilizing effect. CVT-313 inhibited the growth of human lung carcinoma cell line A549 in a dose-dependent manner, with an IC50 of 1.2 µM, which is in line with the reported biochemical potency of 0.5 µM. To support the further chemical modification of CVT-313 and to improve its biochemical and cellular potency, a crystal structure was elucidated in order to understand the molecular interaction of CVT-313 and CDK2. The crystal structure of CDK2 bound to CVT-313 was determined to a resolution of 1.74 Šand clearly demonstrated that CVT-313 binds in the ATP-binding pocket, interacting with Leu83, Asp86 and Asp145 directly, and the binding was further stabilized by a water-mediated interaction with Asn132. Based on the crystal structure, further modifications of CVT-313 are proposed to provide additional interactions with CDK2 in the active site, which may significantly increase the biochemical and cellular potency of CVT-313.

Ternary complex formation of AFN-1252 with Acinetobacter baumannii FabI and NADH: Crystallographic and biochemical studies.

Acinetobacter baumannii is an opportunistic Gram-negative bacterial pathogen, associated mostly with hospital-acquired infections. The emergence of drug resistance strains made it necessary to explore new pathways for the development of more effective antibiotics. Enoyl CoA reductase (FabI), a key enzyme in the fatty acid biosynthesis (FAS) pathway, has emerged as a potential target for antibacterial drug development. Earlier reports show that the lead SaFabI inhibitor AFN-1252 can inhibit FabI from other organisms including Escherichia coli and Burkholderia pseudomallei, but with differential potency. In the present work, we show that AFN-1252 is a moderate inhibitor of AbFabI with an IC50 of 216 nM. AFN-1252 stabilized AbFabI with a 4.2°C increase in the melting temperature (Tm ) and, interestingly, the stabilization effect was significantly increased in presence of the cofactor NADH (∆Tm  = 17°C), suggesting the formation of a ternary complex AbFabI: AFN-1252: NADH. X-ray crystallography studies of AbFabI co-crystalized with AFN-1252 and NADH confirmed the ternary complex formation. The critical interactions of AFN-1252 with AbFabI and NADH identified from the co-crystal structure may facilitate the design and development of new drugs against A. baumannii infections by targeting the FAS pathway.

Outcome of Everolimus-Based Therapy in Hormone-Receptor-Positive Metastatic Breast Cancer Patients After Progression on Palbociclib.

BACKGROUND: Despite the approval of mTOR inhibitor everolimus and CDK4/6 inhibitors in the management of hormone-receptor-positive HER2 non-amplified metastatic breast cancer (HR+ HER2-MBC), the optimal sequence of therapy is unclear. There are no clinical data on efficacy of everolimus in HR+ HER2-MBC after cancer progresses on CDK4/6 inhibitors. OBJECTIVE: The objective of this study is to find the efficacy of everolimus in HR+ HER2-MBC after they progress on a CDK4/6 inhibitor palbociclib. METHODS: This is a retrospective, 2-institute review of HR+ HER2-MBC from Jan 2015 to March 2018 treated with everolimus after progression on palbociclib. Primary end point was median progression-free survival (PFS), secondary end points objective response rate (ORR), clinical benefit ratio (CBR), and overall survival (OS). RESULTS: Out of 41 women with median age 61 years (33, 87) enrolled, 66% had received adjuvant systemic therapy, 61% had visceral disease, and 95% had prior nonsteroidal aromatase inhibitors. About 83% women had 3 or more chemotherapy or hormonal therapies prior to everolimus. Kaplan-Meier estimates showed a median PFS of 4.2 months (95% confidence interval [CI]: 3.2-6.2). The median OS was 18.7 months (95% CI 9.5 to not reached). Objective response rate and CBR were both 17.1%. CONCLUSION: Everolimus was associated with modest PFS and ORR in HR+ HER2-MBCs postprogression on palbociclib.

Selective Vulnerability to Pyrimidine Starvation in Hematologic Malignancies Revealed by AG-636, a Novel Clinical-Stage Inhibitor of Dihydroorotate Dehydrogenase.

Agents targeting metabolic pathways form the backbone of standard oncology treatments, though a better understanding of differential metabolic dependencies could instruct more rationale-based therapeutic approaches. We performed a chemical biology screen that revealed a strong enrichment in sensitivity to a novel dihydroorotate dehydrogenase (DHODH) inhibitor, AG-636, in cancer cell lines of hematologic versus solid tumor origin. Differential AG-636 activity translated to the in vivo setting, with complete tumor regression observed in a lymphoma model. Dissection of the relationship between uridine availability and response to AG-636 revealed a divergent ability of lymphoma and solid tumor cell lines to survive and grow in the setting of depleted extracellular uridine and DHODH inhibition. Metabolic characterization paired with unbiased functional genomic and proteomic screens pointed to adaptive mechanisms to cope with nucleotide stress as contributing to response to AG-636. These findings support targeting of DHODH in lymphoma and other hematologic malignancies and suggest combination strategies aimed at interfering with DNA-damage response pathways.

A new antifungal benzoic acid ester from Uvaria narum.

Uvaria narum has been used for gastrointestinal problems, jaundice, fever and skin diseases in traditional and ethnomedical practices. Our preliminary antifungal screening of various leaf extracts of U. narum revealed very good antifungal activity for its acetone extract. Active principle of U. narum leaf acetone extract was isolated by bioactivity-guided fractionation and characterised as a new molecule, 2-E-(2″-oxo-5″-acetoxy cyclopent-3″-en-1″-ylidene) ethyl benzoate, by NMR, IR and mass spectroscopic analyses. This active isolate showed very good activity against the fungal pathogen, Colletotrichum gloeosporioides.

Formation of DNA nanoparticles in the presence of novel polyamine analogues: a laser light scattering and atomic force microscopic study.

We synthesized a pentamine (3-3-3-3) and two hexamine (3-3-3-3-3 and 3-4-3-4-3) analogues of the natural polyamine, spermine (3-4-3) and studied their effectiveness in condensing pGL3 plasmid DNA, using light scattering and atomic force microscopic (AFM) techniques. The midpoint concentration of the polyamines on pGL3 condensation (EC50) was 11.3, 10.6, 1.5, 0.49 and 0.52 micro M, respectively, for 3-4-3, norspermine (3-3-3), 3-3-3-3, 3-3-3-3-3 and 3-4-3-4-3 in 10 mM Na cacodylate buffer. Dynamic laser light scattering study showed a decrease in hydrodynamic radii of plasmid DNA particles as the number of positive charges on the polyamines increased. AFM data showed the presence of toroids with outer diameter of 117-191 nm for different polyamines, and a mean height of 2.61 +/- 0.77 nm. AFM results also revealed the presence of intermediate structures, including those showing circumferential winding of DNA to toroids. The dependence of the EC50 on Na+ concentration suggests different modes of binding of spermine and its higher valent analogues with DNA. Our results show a 20-fold increase in the efficacy of hexamines for DNA condensation compared to spermine, and provide new insights into the mechanism(s) of DNA nanoparticle formation. These studies might help to develop novel nonviral gene delivery vehicles.

Dependence of alpha-synuclein aggregate morphology on solution conditions.

Alpha-synuclein is the major component of Lewy bodies and Lewy neurites, which are granular and filamentous protein inclusions that are the defining pathological features of several neurodegenerative conditions such as Parkinson's disease. Fibrillar aggregates formed from alpha-synuclein in vitro resemble brain-derived material, but the role of such aggregates in the etiology of Parkinson's disease and their relation to the toxic molecular species remain unclear. In this study, we investigated the effects of pH and salt concentration on the in vitro assembly of human wild-type alpha-synuclein, particularly with regard to aggregation rate and aggregate morphology. Aggregates formed at pH 7.0 and pH 6.0 in the absence of NaCl and MgCl(2) were fibrillar; the pH 6.0 fibrils displayed a helical twist, as clearly evident by scanning force and electron microscopy. Incubations at pH 7.0 remained transparent during the process of aggregation and exhibited strong thioflavin-T and weak 8-anilino-1-naphthalenesulfonate (ANS) binding; furthermore, they were efficient in seeding fibrillization of fresh solutions. In contrast, incubating alpha-synuclein at low pH (pH 4.0 or pH 5.0) resulted in the rapid formation of turbid suspensions characterized by strong ANS binding, reduced thioflavin-T binding and reduced seeding efficiency. At pH 4.0, fibril formation was abrogated; instead, very large aggregates (dimensions approximately 100 microm) of amorphous appearance were visible by light microscopy. As with acidic conditions, addition of 0.2M NaCl or 10mM MgCl(2) to pH 7.0 incubations led to a shorter aggregation lag time and formation of large, amorphous aggregates. These results demonstrate that the morphology of alpha-synuclein aggregates is highly sensitive to solution conditions, implying that the fibrillar state does not necessarily represent the predominant or most functionally significant aggregated state under physiological conditions.

AFN-1252 is a potent inhibitor of enoyl-ACP reductase from Burkholderia pseudomallei--Crystal structure, mode of action, and biological activity.

Melioidosis is a tropical bacterial infection caused by Burkholderia pseudomallei (B. pseudomallei; Bpm), a Gram-negative bacterium. Current therapeutic options are largely limited to trimethoprim-sulfamethoxazole and ß-lactam drugs, and the treatment duration is about 4 months. Moreover, resistance has been reported to these drugs. Hence, there is a pressing need to develop new antibiotics for Melioidosis. Inhibition of enoyl-ACP reducatase (FabI), a key enzyme in the fatty acid biosynthesis pathway has shown significant promise for antibacterial drug development. FabI has been identified as the major enoyl-ACP reductase present in B. pseudomallei. In this study, we evaluated AFN-1252, a Staphylococcus aureus FabI inhibitor currently in clinical development, for its potential to bind to BpmFabI enzyme and inhibit B. pseudomallei bacterial growth. AFN-1252 stabilized BpmFabI and inhibited the enzyme activity with an IC50 of 9.6 nM. It showed good antibacterial activity against B. pseudomallei R15 strain, isolated from a melioidosis patient (MIC of 2.35 mg/L). X-ray structure of BpmFabI with AFN-1252 was determined at a resolution of 2.3 Å. Complex of BpmFabI with AFN-1252 formed a symmetrical tetrameric structure with one molecule of AFN-1252 bound to each monomeric subunit. The kinetic and thermal melting studies supported the finding that AFN-1252 can bind to BpmFabI independent of cofactor. The structural and mechanistic insights from these studies might help the rational design and development of new FabI inhibitors.

Discovery of azetidine based ene-amides as potent bacterial enoyl ACP reductase (FabI) inhibitors.

A novel and potent series of ene-amides featuring azetidines has been developed as FabI inhibitors active against drug resistant Gram-positive pathogens particularly staphylococcal organisms. Most of the compounds from the series possessed excellent biochemical inhibition of Staphylococcus aureus FabI enzyme and whole cell activity against clinically relevant MRSA, MSSA and MRSE organisms which are responsible for significant morbidity and mortality in community as well as hospital settings. The binding mode of one of the leads, AEA16, in Escherichia coli FabI enzyme was determined unambiguously using X-ray crystallography. The lead compounds displayed good metabolic stability in mice liver microsomes and pharmacokinetic profile in mice. The in vivo efficacy of lead AEA16 has been demonstrated in a lethal murine systemic infection model.

A molecular beacon strategy for real-time monitoring of triplex DNA formation kinetics.

We used a molecular beacon (MB) containing a 15-mer triplex-forming oligonucleotide (TFO) to probe in real-time the kinetics of triplex DNA formation in the left side of the TCl tract (502-516) of the c-src proto-oncogene in vitro. The metal ions Na+, K+, and Mg2+ stabilized triplex DNA at this site. The pseudo-first-order rate constant (kpsi) and the second-order association rate constant (k1) for the binding of the MB to the target duplex in 10 mM sodium phosphate buffer, pH 7.3, increased from 3.2 +/- 0.9 to 15 +/- 2.8 x 10(-3) s(-1) and 6.4 +/- 1.8 to 30 +/- 5.6 x 102 M(-1) s(-1), respectively, on increasing the MgCl2 concentration from 1 to 2.5 mM. Similar values were obtained for the triplex DNA stabilized by NaCl (100-250 mM). Surprisingly, the values were around 2 times higher in the presence of KCl. The AG of triplex formation in the presence of 1 mM MgCl2, 150 mM NaCl, and 150 mM KCl were -7.8 +/- 0.3, -8.2 +/- 0.3 and -8.7 +/- 0.7 kcal/mol respectively, despite significant differences in the values of deltaH and deltaS, suggesting enthalpy-entropy compensation in the stabilization of the triplex DNA by these metal ions. These results show the utility of MBs ih probing triplex DNA formation and in evaluating kinetic and thermodynamic parameters important for the design and development of TFOs as triplex DNA-based therapeutic agents.