An early indicator of drug success: Top Journal Selectivity Index

Palmatine, a Bioactive Protoberberine Alkaloid Isolated from Berberis cretica, Inhibits the Growth of Human Estrogen Receptor-Positive Breast Cancer Cells and Acts Synergistically and Additively with Doxorubicin

Palmatine (PLT) is a natural isoquinoline alkaloid that belongs to the class of protoberberines and exhibits a wide spectrum of pharmacological and biological properties, including anti-cancer activity. The aim of our study was to isolate PLT from the roots of Berberis cretica and investigate its cytotoxic and anti-proliferative effects in vitro alone and in combination with doxorubicine (DOX) using human ER⁺/HER2⁻ breast cancer cell lines. The alkaloid was purified by column chromatography filled with silica gel NP and Sephadex LH-20 resin developed in the mixture of methanol: water (50:50 v/v) that provided high-purity alkaloid for bioactivity studies. The purity of the alkaloid was confirmed by high resolution mass measurement and MS/MS fragmentation analysis in the HPLC-ESI-QTOF-MS/MS-based analysis. It was found that PLT treatment inhibited the viability and proliferation of breast cancer cells in a dose-dependent manner as demonstrated by MTT and BrdU assays. PLT showed a quite similar growth inhibition on breast cancer cells with IC₅₀ values ranging from 5.126 to 5.805 µg/mL. In contrast, growth of normal human breast epithelial cells was not affected by PLT. The growth inhibitory activity of PLT was related to the induction of apoptosis, as determined by Annexin V/PI staining. Moreover, PLT sensitized breast cancer cells to DOX. Isobolographic analysis revealed synergistic and additive interactions between studied agents. Our studies suggest that PLT can be a potential candidate agent for preventing and treating breast cancer.

Antiplasmodial and Cytotoxic Activities of Extracts of Selected Medicinal Plants Used to Treat Malaria in Embu County, Kenya

Malaria is a deadly disease caused by a protozoan parasite whose mode of transmission is through a female Anopheles mosquito. It affects persons of all ages; however, pregnant mothers, young children, and the elderly suffer the most due to their dwindled immune state. The currently prescribed antimalarial drugs have been associated with adverse side effects ranging from intolerance to toxicity. Furthermore, the costs associated with conventional approach of managing malaria are arguably high especially for persons living in low-income countries, hence the need for alternative and complementary approaches. Medicinal plants offer a viable alternative because of their few associated side effects, are arguably cheaper, and are easily accessible. Based on the fact that studies involving antimalarial medicinal plants as potential sources of efficacious and cost-effective pharmacotherapies are far between, this research was designed to investigate antiplasmodial and cytotoxic activities of organic and aqueous extracts of selected plants used by Embu traditional medicine practitioners to treat malaria. The studied plants included Erythrina abyssinica (stem bark), Schkuhria pinnata (whole plant), Sterculia africana (stem bark), Terminalia brownii (leaves), Zanthoxylum chalybeum (leaves), Leonotis mollissima (leaves), Carissa edulis (leaves), Tithonia diversifolia (leaves and flowers), and Senna didymobotrya (leaves and pods). In vitro antiplasmodial activity studies of organic and water extracts were carried out against chloroquine-sensitive (D6) and chloroquine-resistance (W2) strains of Plasmodium falciparum. In vivo antiplasmodial studies were done by Peter's four-day suppression test to test for their in vivo antimalarial activity against P. berghei. Finally, cytotoxic effects and safety of the studied plant extracts were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) rapid calorimetric assay technique. The water and methanolic extracts of T. brownii and S. africana and dichloromethane extracts of E. abyssinica, S. pinnata, and T. diversifolia leaves revealed high in vitro antiplasmodial activities (IC₅₀ ≤ 10 μg/ml). Further, moderate in vivo antimalarial activities were observed for water and methanolic extracts of L. mollissima and S. africana and for dichloromethane extracts of E. abyssinica and T. diversifolia leaves. In this study, aqueous extracts of T. brownii and S. africana demonstrated high antiplasmodial activity and high selectivity indices values (SI ≥ 10) and were found to be safe. It was concluded that T. brownii and S. africana aqueous extracts were potent antiplasmodial agents. Further focused studies geared towards isolation of active constituents and determination of in vivo toxicities to ascertain their safety are warranted.

Indices of Change, Expectations, and Popularity of Biological Treatments for Major Depressive Disorder between 1988 and 2017: A Scientometric Analysis

Background. Major Depressive Disorder (MDD) is the most common psychiatric disorder with high prevalence and disease burden. Biological treatments of MDD over the last several decades include a wide range of antidepressants and neurostimulation therapies. While recent meta-analyses have explored the efficacy and tolerability of antidepressants, the changing trends of biological treatments have not been evaluated. Our study measured the indices of change, expectations, and popularity of biological treatments of MDD between 1988 and 2017. Methods. We performed a scientometric analysis to identify all relevant publications related to biological treatments of MDD from 1988 to 2017. We searched the Web of Science websites for publications from 1 January 1988 to 31 December 2017. We included publications of fluoxetine, paroxetine, citalopram, sertraline, amitriptyline, fluvoxamine, escitalopram, venlafaxine, duloxetine, milnacipran, desvenlafaxine, levomilnacipran, clomipramine, nortriptyline, bupropion, trazodone, nefazodone, mirtazapine, agomelatine, vortioxetine, vilazodone, electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation (rTMS), vagus nerve stimulation (VNS), deep brain stimulation (DBS), and transcranial direct current stimulation (tDCS). We excluded grey literature, conference proceedings, books/book chapters, and publications with low quality as well as publications not related to medicine or human health. The primary outcomes assessed were indices of change, expectations, and popularity. Results. Of 489,496 publications identified, we included 355,116 publications in this scientometric analysis. For the index of change, fluoxetine, sertraline and ECT demonstrated a positive index of change in 6 consecutive periods. Other neurostimulation therapies including rTMS, VNS, DBS and tDCS had shown a positive index of change since 1998. We calculated the index of change of popularity index (PI), which indicates that from 2013 to 2017, the number of publications on tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) were reduced by 85.0% and 81.3% respectively, as compared with the period 2008–2012. For the index of expectation, fluoxetine and ECT showed the highest index of expectations in six consecutive periods and remained the highest in 2013–2017. For popularity, the three antidepressants with highest PI were fluoxetine (4.01), paroxetine (2.09), and sertraline (1.66); the three antidepressants with lowest PI were desvenlafaxine (0.08), vilazodone (0.04) and levomilnacipran (0.03). Among neurostimulation therapies, ECT has the highest PI (2.55), and tDCS the lowest PI (0.14). The PI of SSRI remained the highest among all biological treatments of MDD in 2013–2017. In contrast, the PI of ECT was reduced by approximately 50% during the period 2008 to2012 than that in the period 2013 to 2017. Conclusions. This scientometric analysis represents comprehensive evidence on the popularity and change in prospects of biological treatments for MDD from 1988 to 2017. The popularity of SSRI peaked between 1998 and 2002, when their efficacy, tolerability and safety profile allowed them to replace the TCAs and MAOIs. While the newer neurostimulation therapies are gaining momentum, the popularity of ECT has sustained.

Recent History of Publication-Based Academic Interest in General Anesthetics

PURPOSE

The aim of this study was to determine how interest in various general anesthetics among the authors of academic publications changed over the past 50 years.

METHODS

Publication-based academic interest were analyzed using specific scientometric indices: popularity index (PI), top journal selectivity index (TJSI), and index of change (IC). Terms used for searches were the names of drugs belonging to two pharmacological classes of general anesthetics - inhaled and intravenous. Only those that had a PI value > 2.0 during at least one of the 10 five-year periods, from 1967 to 2016, were selected.

RESULTS

The PI, an index of comparative popularity, reflects a consistent decline in academic interest over time in both classes of general anesthetics. Over the past 25 years, the PI of inhaled anesthetics decreased by 52 %, and that of intravenous anesthetics fell by 32%. At the same time, the PI of anesthesia management increased by 167%. Among individual anesthetics, the most impressive change was a profound decline in halothane's PI, from 22.9 in 1972-1976 to 0.5 in 2012-2016. The interest in halothane was gradually supplanted by that in new agents, initially by enflurane, followed by isoflurane and finally, sevoflurane. The next meaningful change was the gradual rise in sevoflurane's PI to surpass that of isoflurane. The most dramatic change among the PIs of intravenous anesthetics was associated with the introduction of propofol: an increase from 1.8 to its maximum of 13.6.

CONCLUSIONS

The study revealed a constant decline over time in academic interest in the pharmacological basis of general anesthesia relative to all fields of anesthesia combined.

Publication-Based Academic Interest in Drugs and Techniques for Treatment of Postoperative Pain, 1975-2015

PURPOSE

The aim of this study was to determine how drugs and their administration techniques, introduced over the past 40 years and still popular now, influenced publication-based academic interest in the treatment of postoperative pain.

METHODS

Specific scientometric indices-popularity index (PI), top journal selectivity index (TJSI), and index of change (IC)-were used. Of the 61 terms searched, only those that had a PI value ≥1.0 during the 2011-2015 period were selected. They include eight drugs-bupivacaine, fentanyl, ropivacaine, acetaminophen, tramadol, remifentanil, and dexamethasone-and five techniques-patient-controlled analgesia, epidural opioids, ultrasound-guided nerve blocks, continuous nerve blocks, and transversus abdominis plane block (presented according to their decreasing PI value in each category).

RESULTS

Four of these drugs or techniques with the highest PI in 2011-2015 also held top positions even 20 years earlier: in 1991-1995, the PI for bupivacaine was 9.1; fentanyl, 6.6; patient-controlled analgesia, 10.4; and epidural opioids, 6.8. Since that time, their PI values slowly decreased, for the first three items by approximately 50% and much more than that (85%) with epidural opioids. Nevertheless, to this day, they continue to hold the highest degree of publication-based academic interest. The TJSI can be regarded as an index of expectations at the time of articles publication. With bupivacaine, fentanyl, patient-controlled analgesia, and epidural opioids, the TJSI exceeded the specific high threshold of 10.0 for a very long time. The TJSIs of acetaminophen, ketamine, and dexamethasone were increased with the advent of new expectations regarding the treatment of postoperative pain using these old agents.

CONCLUSIONS

Two important developments related to ultrasound-guided nerve block and continuous nerve block demonstrated only a moderate degree of academic interest. In conclusion, even today, the greatest publication-based academic interest related to postoperative pain is associated with drugs and techniques introduced 40-50 years ago.

Scientometrics of drug discovery efforts: pain-related molecular targets

The aim of this study was to make a scientometric assessment of drug discovery efforts centered on pain-related molecular targets. The following scientometric indices were used: the popularity index, representing the share of articles (or patents) on a specific topic among all articles (or patents) on pain over the same 5-year period; the index of change, representing the change in the number of articles (or patents) on a topic from one 5-year period to the next; the index of expectations, representing the ratio of the number of all types of articles on a topic in the top 20 journals relative to the number of articles in all (>5,000) biomedical journals covered by PubMed over a 5-year period; the total number of articles representing Phase I–III trials of investigational drugs over a 5-year period; and the trial balance index, a ratio of Phase I–II publications to Phase III publications. Articles (PubMed database) and patents (US Patent and Trademark Office database) on 17 topics related to pain mechanisms were assessed during six 5-year periods from 1984 to 2013. During the most recent 5-year period (2009–2013), seven of 17 topics have demonstrated high research activity (purinergic receptors, serotonin, transient receptor potential channels, cytokines, gamma aminobutyric acid, glutamate, and protein kinases). However, even with these seven topics, the index of expectations decreased or did not change compared with the 2004–2008 period. In addition, publications representing Phase I–III trials of investigational drugs (2009–2013) did not indicate great enthusiasm on the part of the pharmaceutical industry regarding drugs specifically designed for treatment of pain. A promising development related to the new tool of molecular targeting, ie, monoclonal antibodies, for pain treatment has not yet resulted in real success. This approach has not yet demonstrated clinical effectiveness (at least with nerve growth factor) much beyond conventional analgesics, when its potential cost is more than an order of magnitude higher than that of conventional treatments. This scientometric assessment demonstrated a lack of real breakthrough developments.

A quest to increase safety of anesthetics by advancements in anesthesia monitoring: scientometric analysis

The aim of this study was to assess progress in the field of anesthesia monitoring over the past 40 years using scientometric analysis. The following scientometric indexes were used: popularity indexes (general and specific), representing the proportion of articles on either a topic relative to all articles in the field of anesthetics (general popularity index, GPI) or the subfield of anesthesia monitoring (specific popularity index, SPI); index of change (IC), representing the degree of growth in publications on a topic from one period to the next; and index of expectations (IE), representing the ratio of the number of articles on a topic in the top 20 journals relative to the number of articles in all (>5,000) biomedical journals covered by PubMed. Publications on 33 anesthesia-monitoring topics were assessed. Our analysis showed that over the past 40 years, the rate of rise in the number of articles on anesthesia monitoring was exponential, with an increase of more than eleven-fold, from 296 articles over the 5-year period 1974–1978 to 3,394 articles for 2009–2013. This rise profoundly exceeded the rate of rise of the number of articles on general anesthetics. The difference was especially evident with the comparison of the related GPIs: stable growth of the GPI for anesthesia monitoring vs constant decline in the GPI for general anesthetics. By the 2009–2013 period, among specific monitoring topics introduced after 1980, the SPI index had a meaningful magnitude (≥1.5) in 9 of 24 topics: Bispectral Index (7.8), Transesophageal Echocardiography (4.2), Electromyography (2.8), Pulse Oximetry (2.4), Entropy (2.3), Train-of-four (2.3), Capnography (1.9), Pulse Contour (1.9), and Electrical Nerve Stimulation for neuromuscular monitoring (1.6). Only one of these topics (Pulse Contour) demonstrated (in 2009–2013) high values for both IC and IE indexes (76 and 16.9, respectively), indicating significant recent progress. We suggest that rapid growth in the field of anesthetic monitoring was one of the most important developments to compensate for the intrinsically low margins of safety of anesthetic agents.

Scientometrics of anesthetic drugs and their techniques of administration, 1984-2013

The aim of this study was to assess progress in the field of anesthetic drugs over the past 30 years using scientometric indices: popularity indices (general and specific), representing the proportion of articles on a drug relative to all articles in the field of anesthetics (general index) or the subfield of a specific class of anesthetics (specific index); index of change, representing the degree of growth in publications on a topic from one period to the next; index of expectations, representing the ratio of the number of articles on a topic in the top 20 journals relative to the number of articles in all (>5,000) biomedical journals covered by PubMed; and index of ultimate success, representing a publication outcome when a new drug takes the place of a common drug previously used for the same purpose. Publications on 58 topics were assessed during six 5-year periods from 1984 to 2013. Our analysis showed that during 2009–2013, out of seven anesthetics with a high general popularity index (≥2.0), only two were introduced after 1980, ie, the inhaled anesthetic sevoflurane and the local anesthetic ropivacaine; however, only sevoflurane had a high index of expectations (12.1). Among anesthetic adjuncts, in 2009–2013, only one agent, sugammadex, had both an extremely high index of change (>100) and a high index of expectations (25.0), reflecting the novelty of its mechanism of action. The index of ultimate success was positive with three anesthetics, ie, lidocaine, isoflurane, and propofol, all of which were introduced much longer than 30 years ago. For the past 30 years, there were no new anesthetics that have produced changes in scientometric indices indicating real progress.

Scientometric assessment of drugs for chronic pain, 1979-2013: rapid growth of publications, paucity of successful drugs

The aim of this study was to find signs of progress in the pharmacotherapy of chronic pain over the past 35 years using scientometric analysis. The following scientometric indices were used: 1) popularity index, representing the share of articles on a specific drug(s) relative to all articles in the field of chronic pain; 2) index of change, representing the degree of growth in publications on a topic from one period to the next; 3) index of expectations, representing the ratio of the number of articles on a topic in the top 20 journals relative to the number of articles in all (>5,000) biomedical journals covered by PubMed; and 4) index of ultimate success, representing a publication outcome when a new drug takes the place of a common drug previously used for the same purpose. Publications on 55 drugs used in the treatment of chronic pain were assessed during seven 5-year periods, from 1979 to 2013. The rate of rise in the number of publications on chronic pain was exponential, with an increase of nearly ninefold from 2,346 articles over the 5-year period 1979–1983 to 21,095 articles in 2009–2013. However, despite this huge increase in publications, our scientometric analysis did not reveal signs of really successful drugs in this field. For the 2009–2013 period, the popularity index had a meaningful magnitude (from 0.5–2.8) for only 13 of 55 drugs. Five of them were opioids, including morphine, which had the highest index value of all drugs (2.8). None of the drugs had a high index of expectations in 2009–2013. The index of ultimate success was positive only with triptans in the relatively limited area of acute treatment of migraine. As a result, despite rapid growth in the number of publications, our scientometric analysis did not reveal signs of substantial progress in the field of pharmacotherapy for chronic pain.

No evidence of real progress in treatment of acute pain, 1993-2012: scientometric analysis

Over the past 2 decades, many new techniques and drugs for the treatment of acute pain have achieved widespread use. The main aim of this study was to assess the progress in their implementation using scientometric analysis. The following scientometric indices were used: 1) popularity index, representing the share of articles on a specific technique (or a drug) relative to all articles in the field of acute pain; 2) index of change, representing the degree of growth in publications on a topic compared to the previous period; and 3) index of expectations, representing the ratio of the number of articles on a topic in the top 20 journals relative to the number of articles in all (>5,000) biomedical journals covered by PubMed. Publications on specific topics (ten techniques and 21 drugs) were assessed during four time periods (1993–1997, 1998–2002, 2003–2007, and 2008–2012). In addition, to determine whether the status of routine acute pain management has improved over the past 20 years, we analyzed surveys designed to be representative of the national population that reflected direct responses of patients reporting pain scores. By the 2008–2012 period, popularity index had reached a substantial level (≥5%) only with techniques or drugs that were introduced 30–50 years ago or more (epidural analgesia, patient-controlled analgesia, nerve blocks, epidural analgesia for labor or delivery, bupivacaine, and acetaminophen). In 2008–2012, promising (although modest) changes of index of change and index of expectations were found only with dexamethasone. Six national surveys conducted for the past 20 years demonstrated an unacceptably high percentage of patients experiencing moderate or severe pain with not even a trend toward outcome improvement. Thus, techniques or drugs that were introduced and achieved widespread use for acute pain management within the past 20 years have produced no changes in scientometric indices that would indicate real progress and have failed to improve national outcomes for relief of acute pain. Two possible reasons for this are discussed: 1) the difference between the effectiveness of old and new techniques is not clinically meaningful; and 2) resources necessary for appropriate use of new techniques in routine pain management are not adequate.