Synthesis of oligodeoxyribonucleotides containing a tricyclic thio analogue of O6-methylguanine and their recognition by MGMT and Atl1

Promutagenic O⁶-alkylguanine adducts in DNA are repaired in humans by O⁶-methylguanine-DNA-methyltransferase (MGMT) in an irreversible reaction. Here we describe the synthesis of a phosphoramidite that allows the preparation of oligodeoxyribonucleotides (ODNs) containing a novel tricyclic thio analogue of O⁶-methylguanine in which the third ring bridges the 6-thio group and C7 of a 7-deazapurine. These ODNs are very poor substrates for MGMT and poorly recognised by the alkyltransferase-like protein, Atl1. Examination of the active sites of both MGMT and Atl1 suggest large steric clashes hindering binding of the analogue. Such analogues, if mutagenic, are likely to be highly toxic.

In vivo electrophysiological recordings of the effects of antidepressant drugs

Antidepressant drugs are a standard biological treatment for various neuropsychiatric disorders, yet relatively little is known about their electrophysiologic and synaptic effects on mood systems that set moment-to-moment emotional tone. In vivo electrical recording of local field potentials (LFPs) and single neuron spiking has been crucial for elucidating important details of neural processing and control in many other systems, and yet electrical approaches have not been broadly applied to the actions of antidepressants on mood-related circuits. Here we review the literature encompassing electrophysiologic effects of antidepressants in animals, including studies that examine older drugs, and extending to more recently synthesized novel compounds, as well as rapidly acting antidepressants. The existing studies on neuromodulator-based drugs have focused on recording in the brainstem nuclei, with much less known about their effects on prefrontal or sensory cortex. Studies on neuromodulatory drugs have moreover focused on single unit firing patterns with less emphasis on LFPs, whereas the rapidly acting antidepressant literature shows the opposite trend. In a synthesis of this information, we hypothesize that all classes of antidepressants could have common final effects on limbic circuitry. Whereas NMDA receptor blockade may induce a high powered gamma oscillatory state via direct and fast alteration of glutamatergic systems in mood-related circuits, neuromodulatory antidepressants may induce similar effects over slower timescales, corresponding with the timecourse of response in patients, while resetting synaptic excitatory versus inhibitory signaling to a normal level. Thus, gamma signaling may provide a biomarker (or “neural readout”) of the therapeutic effects of all classes of antidepressants.

Associations of C-reactive protein and psychological distress are modified by antidepressants, supporting an inflammatory depression subtype: Findings from UKHLS

BACKGROUND

Clinical evidence increasingly suggests inflammation may be important specifically for an etiologically distinct depression subtype, characterised by resistance to antidepressant medication. However, epidemiological investigations of the relationship of inflammation with depression and psychological distress have failed to acknowledge these developments, which may have resulted in bias or masking of associations driven by the subtype. This may have contributed to inconsistent results in epidemiological studies, and equivocal support for an inflammation-depression link.

METHODS

An antidepressant-resistant, inflammatory depression subtype would result in stronger associations of depressive symptomatology with inflammation among antidepressant users than non-users, due to over-representation of subtype individuals among antidepressant users experiencing severe or persistent symptoms. We investigate, in a sample of 10,363 UK adults aged 16-98, modification by antidepressants of cross-sectional and longitudinal associations between C-reactive protein and psychological distress (General Health Questionnaire score, GHQ). We account for confounding by age, gender, income, inflammatory somatic illness, body mass index and, in longitudinal models, baseline psychological distress. Sensitivity analyses consider smoking, ethnicity, and other medications.

RESULTS

Robust associations of log-CRP and GHQ were seen for antidepressant users but not for non-users in both cross-sectional (coeff: 0.54, p=0.01vs 0.06, p=0.28) and longitudinal models (coeff: 0.57, p=0.006vs 0.04, p=0.39 two waves post-baseline). Cross-sectional associations were strongest for tricyclic users, and longitudinal associations strongest for SSRI users. In multilevel, repeated-measures longitudinal models, associations for antidepressant users peaked two waves after baseline before declining.

CONCLUSIONS

Results suggest evidence for existence of an inflammatory depression subtype. Previous studies' exclusion of antidepressant users and failure to consider interactive effects may have obscured associations driven by the subgroup. Follow-up work is now needed in community samples with clinical depression measures and prescription histories, to further elucidate the mechanisms involved.

Antidepressants and risk of dementia in migraine patients: A population-based case-control study

To ascertain the relationship between receipt of antidepressant agents and the risk of subsequent dementia in migraine patients. A population-based case-control analysis, using the Taiwan National Health Insurance Research Database. We identified 1774 patients with dementia and 1774 matched nondementia controls from migraine patients enrolled in the Taiwan National Health Insurance program between 2005 and 2011. The proportional distributions of exposure to three classes of antidepressant were compared between dementia and nondementia groups. Univariable and multivariable logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of dementia based on antidepressant exposure. The proportions of subjects taking tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and new-generation antidepressants (NGAs) in dementia versus nondementia groups are 52.3 vs 51.2%, 25.5 vs 30.7%, and 18.8 vs 6.26%, respectively. The adjusted ORs of dementia were 1.02 (95% CI=0.89, 1.17; P=0.56) for TCAs, 0.58 (95% CI=0.50, 0.69; P<0.001) for SSRIs, and 4.23 (95% CI=3.34, 5.37; P<0.001) for NGAs. Treatment with SSRIs was associated with a decreased risk of dementia in migraine patients. TCAs showed no association with dementia risk, and NGAs showed increased risk. Given the possibility of confounding by indication, additional prospective trials and basic research are needed before drawing conclusions about the population-level risks for dementia onset conferred by antidepressant medications.

Novel tricyclic poly (ADP-ribose) polymerase-1/2 inhibitors with potent anticancer chemopotentiating activity: Design, synthesis and biological evaluation

8,9-Dihydro-2,4,7,9a-tetraazabenzo[cd]azulen-6(7H)-ones were designed and synthesized as a new class of PARP-1/2 inhibitors. The compounds displayed a variable pattern of PARP-1/2 enzymes inhibition profile that, in part, paralleled the antiproliferative activity in cell lines. Among them, compound 9e exhibited not only the significant IC50 value of 28nM in the PARP-1 and 7.7nM in PARP-2 enzyme assay, but also a profound synergic efficacy combined with temozolomide with PF50 values of 2.6, 2.5, and 6.5 against MDA-MB-468, SW-620 and A549 and cell line, respectively.

Discovery of fused tricyclic core containing HCV NS5A inhibitors with pan-genotype activity

HCV NS5A inhibitors have demonstrated impressive in vitro potency profiles in HCV replicon assays and robust HCV RNA titer reduction in the clinic making them attractive components for inclusion in an all oral fixed dose combination regimen for the treatment of HCV infection. Herein, we describe research efforts that led to the discovery of a series of fused tricyclic core containing HCV NS5A inhibitors such as 24, 39, 40, 43, and 44 which have pan-genotype activity and are orally bioavailable in the rat.

Pharmacologic Management of Upper Extremity Chronic Nerve Pain

The treatment of pain is a complex process that requires a team approach. This article provides an overview of the pharmaceutical treatments available. It gives providers treating upper extremity disorders more tools to treat their patients with chronic pain. Another goal is to improve hand providers' understanding of the medications their pain colleagues prescribe in shared patients. Pharmaceuticals are an important component in the treatment of chronic pain and opioids are often not a good solution. Knowing what other medications are available can improve the care for these challenging patients.

Thiophene-expanded guanosine analogues of Gemcitabine

The chemotherapeutic drug Gemcitabine, 2',2'-difluoro-2'-deoxycytidine, has long been the standard of care for a number of cancers. Gemcitabine's chemotherapeutic properties stem from its 2',2'-difluoro-2'-deoxyribose sugar, which mimics the natural nucleoside, but also disrupts nucleic acid synthesis, leading to cell death. As a result, numerous analogues have been prepared to further explore the biological implications for this structural modification. In that regard, a thieno-expanded guanosine analogue was of interest due to biological activity previously observed for the tricyclic heterobase scaffold. Several analogues were prepared, including the McGuigan ProTide, however the parent nucleoside exhibited the best chemotherapeutic activity, specifically against breast cancer cell lines (89.53% growth inhibition).

Reengineered tricyclic anti-cancer agents

The phenothiazine and dibenzazepine tricyclics are potent neurotropic drugs with a documented but underutilized anti-cancer side effect. Reengineering these agents (TFP, CPZ, CIP) by replacing the basic amine with a neutral polar functional group (e.g., RTC-1, RTC-2) abrogated their CNS effects as demonstrated by in vitro pharmacological assays and in vivo behavioral models. Further optimization generated several phenothiazines and dibenzazepines with improved anti-cancer potency, exemplified by RTC-5. This new lead demonstrated efficacy against a xenograft model of an EGFR driven cancer without the neurotropic effects exhibited by the parent molecules. Its effects were attributed to concomitant negative regulation of PI3K-AKT and RAS-ERK signaling.

Antidepressant use and the risk of suicide: a population-based cohort study

BACKGROUND

The existing literature provides contradictory evidence on antidepressant use and risk of suicide. Some studies have shown that the use of Selective Serotonin Reuptake Inhibitors (SSRIs) is associated with an increased risk of suicide, especially during the first months of treatment, whereas other studies did not confirm this association. For this reason, our objective was to investigate the association between antidepressant use and risk of suicide in incident antidepressant users in relation to time since starting therapy.

METHODS

We conducted a population-based cohort study within the Dutch Integrated Primary Care Information (IPCI) database, in incident users of antidepressant therapy between 1994 and 2012 (n=27,712). Cox proportional hazard models were used to study the association between current use of SSRIs, tricyclic antidepressants (TCA) and other antidepressants and risk of suicide or attempted suicide.

RESULTS

During follow-up, a total of 280 incident antidepressant users attempted or committed suicide. Current use of SSRIs (hazard ratio (HR): 0.78, 95% CI: 0.57-1.07), TCAs (HR: 0.82, 95% CI: 0.48-1.42) or other antidepressants (HR: 0.75, 95% CI: 0.47-1.18) was not statistically significantly associated with suicide compared to past use of any of the antidepressants.

LIMITATIONS

Although a large healthcare database was used, the number of reported cases of suicide (attempt) was low.

CONCLUSIONS

This study did not indicate an increase in risk of suicide after starting treatment with SSRIs, TCAs or other antidepressants compared with past antidepressant use.

Mini review on tricyclic compounds as an inhibitor of trypanothione reductase

Trypanosomiasis and leishmaniasis are two most ruinous parasitic infectious diseases caused by Trypanosoma and Leishmania species. The disease affects millions of people all over the world and associated with high morbidity and mortality rates. The review discuss briefly on current treatment of these parasitic diseases and trypanothione reductase (TryR) as potential targets for rational drug design. The enzyme trypanothione reductase (TryR) has been identified as unique among these parasites and has been proposed to be an effective target against for developing new drugs. The researchers have selected this enzyme as target is due to its substrate specificity in contrast to human analogous glutathione reductase and its absence from the host cell which makes this enzyme an ideal target for drug discovery. In this review we have tried to present an overview of the different tricyclic compounds which are potent inhibitors of TryR with their inhibitory activities against the parasites are briefly discussed.

Evaluation of Pharmaceutical Products of St. John's Wort Efficacy Added on Tricyclic Antidepressants in treating Major Depressive Disorder: A Double Blind Randomized Control Trial

BACKGROUND

Major depressive disorder (MDD) is the most common disorder in our community. Hypericum perforatumm, is a herb with a long application history in treating depression. A controlled study to evaluate the effects of this herbal medicine in Iran did not exist.

OBJECTIVES

This study aimed to assess the effect of Hypericum perforatom (perforan), in combination with tricyclic antidepressants in MDD treatment.

MATERIALS AND METHODS

The present study was a placebo-controlled double blind randomized clinical trial including 40 patients with major depressive disorder who referred to Psychiatric Clinic and Golestan Hospital in 2011. Patients were randomly distributed in 4 blocks with 10 patients in each. 5 out of 10 patients took medicine (group I) and the others received placebo (group II).

RESULTS

After six weeks, both groups indicated some improvement, there was also a significant degree of recovery in the perforan group (P = 0.04).

CONCLUSIONS

The results of the current study suggested that combinations of St. John's Wort and tricyclic antidepressants compared to tricyclic antidepressants alone had significant effect on mild to moderate depression improvement. According to the numerous side effects of antidepressants, their continuous use was not well tolerated. There is a strong global tendency to use herbal medicines. Hypericum perforatom (St. John's Wort) is one of the best types of unapproved MDD treatments. Also, the most common reason to discontinue antidepressant treatments is their sexual side effects. None of the patients in the two groups had complained about sexual side effects which was consistent with other studies and it was an advantage of using this herbal medicine. Perforan group had improved in quality of sleep and the increase of energy. This improvement had not been reported in previous studies. Sleep problems are common complications of specific serotonin reuptake inhibitors (SSRIs).