Automated Assessment of the DWI-FLAIR Mismatch in Patients with Acute Ischemic Stroke: Added Value to Routine Clinical Practice

BACKGROUND AND PURPOSE

The DWI-FLAIR mismatch is used to determine thrombolytic eligibility in patients with acute ischemic stroke when the time since stroke onset is unknown. Commercial software packages have been developed for automated DWI-FLAIR classification. We aimed to use e-Stroke software for automated classification of the DWI-FLAIR mismatch in a cohort of patients with acute ischemic stroke and in a comparative analysis with 2 expert neuroradiologists.

MATERIALS AND METHODS

In this retrospective study, patients with acute ischemic stroke who had MR imaging and known time since stroke onset were included. The DWI-FLAIR mismatch was evaluated by 2 neuroradiologists blinded to the time since stroke onset and automatically by the e-Stroke software. After 4 weeks, the neuroradiologists re-evaluated the MR images, this time equipped with automated predicted e-Stroke results as a computer-assisted tool. Diagnostic performances of e-Stroke software and the neuroradiologists were evaluated for prediction of DWI-FLAIR mismatch status.

RESULTS

A total of 157 patients met the inclusion criteria. A total of 82 patients (52%) had a time since stroke onset of ≤4.5 hours. By means of consensus reads, 81 patients (51.5%) had a DWI-FLAIR mismatch. The diagnostic accuracy (area under the curve/sensitivity/specificity) of e-Stroke software for the determination of the DWI-FLAIR mismatch was 0.72/90.0/53.9. The diagnostic accuracy (area under the curve/sensitivity/specificity) for neuroradiologists 1 and 2 was 0.76/69.1/84.2 and 0.82/91.4/73.7, respectively; both significantly (P < .05) improved to 0.83/79.0/86.8 and 0.89/92.6/85.5, respectively, following the use of e-Stroke predictions as a computer-assisted tool. The interrater agreement (κ) for determination of DWI-FLAIR status was improved from 0.49 to 0.57 following the use of the computer-assisted tool.

CONCLUSIONS

This automated quantitative approach for DWI-FLAIR mismatch provides results comparable with those of human experts and can improve the diagnostic accuracies of expert neuroradiologists in the determination of DWI-FLAIR status.

Overestimation of ischemic core on baseline MRI in acute stroke

BACKGROUND AND PURPOSE

In patients with acute ischemic stroke (AIS), overestimation of ischemic core on MRI-DWI has been described primarily in regions with milder reduced diffusion. We aimed to assess the possibility of ischemic core overestimation on pretreatment MRI despite using more restricted reduced diffusion (apparent diffusion coefficient (ADC) ≤620 × 10-6 mm2/s) in AIS patients with successful reperfusion.

MATERIALS AND METHODS

In this retrospective single institutional study, AIS patients who had pretreatment MRI underwent successful reperfusion and had follow-up MRI to determine the final infarct volume were reviewed. Pretreatment ischemic core and final infarction volumes were calculated. Ghost core was defined as overestimation of final infarct volume by baseline MRI of >10 mL. Baseline clinical, demographic, and treatment-related factors in this cohort were reviewed.

RESULTS

A total of 6/156 (3.8%) patients had overestimated ischemic core volume on baseline MRI, with mean overestimation of 65.6 mL. Three out of six patients had pretreatment ischemic core estimation of >70 mL, while the final infarct volume was <70 mL. All six patients had last known well-to-imaging <120 min, median (IQR): 65 (53-81) minutes.

CONCLUSIONS

Overestimation of ischemic core, known as ghost core, is rare using severe ADC threshold (≤620 × 10-6 mm2/s), but it does occur in nearly 1 of every 25 patients, confined to hyperacute patients imaged within 120 min of symptom onset. Awareness of this phenomenon carries implications for treatment and trial enrollment.

CTP-based estimated ischemic core: A comparative multicenter study between Olea and RAPID software

BACKGROUND AND PURPOSE

CTP is increasingly used to assess eligibility for endovascular therapy (EVT) in patients with large vessel occlusions (LVO). There remain variability and inconsistencies between software packages for estimation of ischemic core. We aimed to use heterogenous data from four stroke centers to perform a comparative analysis for CTP-estimated ischemic core between RAPID (iSchemaView) and Olea (Olea Medical).

METHODS

In this retrospective multicenter study, patients with anterior circulation LVO who underwent pretreatment CTP, successful EVT (defined TICI ≥ 2b), and follow-up MRI included. Automated CTP analysis was performed using Olea platform [rCBF < 25% and differential time-to-peak (dTTP)>5s] and RAPID (rCBF < 30%). The CTP estimated core volumes were compared against the final infarct volume (FIV) on post treatment MRI-DWI.

RESULTS

A total of 151 patients included. The CTP-estimated ischemic core volumes (mean ± SD) were 18.7 ± 18.9 mL on Olea and 10.5 ± 17.9 mL on RAPID significantly different (p < 0.01). The correlation between CTP estimated core and MRI final infarct volume was r = 0.38, p < 0.01 for RAPID and r = 0.39, p < 0.01 for Olea. Both software platforms demonstrated a strong correlation with each other (r = 0.864, p < 0.001). Both software overestimated the ischemic core volume above 70 mL in 4 patients (2.6%).

CONCLUSIONS

Substantial variation between Olea and RAPID CTP-estimated core volumes exists, though rates of overcalling of large core were low and identical. Both showed comparable core volume correlation to MRI infarct volume.

Repeat breeding: prevalence and potential causes in dairy cows at different milk pocket areas of Bangladesh

The objective of this study was to figure out the prevalence and probable causes of repeat breeding (RB) in dairy cows. Hence, a cross-sectional study was conducted on randomly selected 265 dairy farms in Sirajganj, Bogura, Rangpur, Satkhira, and Munshiganj districts of Bangladesh from December 2018 to February 2019. Data were collected through a direct interview method using a survey questionnaire. The reproductive organs of repeat breeder cows were examined for pathological, infectious, and functional reasons, and genital tract abnormalities. Additionally, the influence of nutrition, season, and age on the frequency of RB was recorded. The prevalence of RB was 28% among the 3824 cows investigated. Among the total repeat breeder cases, 72.54% of RB cases were found in Holstein-Friesian crossbred, 23.90% in Jersey crossbred, 1.50% in Sahiwal crossbred, and 2.06% in indigenous cows. The prevalence of RB was significantly highest (P < 0.01) in Satkhira (44.35%) and lowest in the Munshiganj district (15.87%). Data indicated that a major proportion of cows significantly (P < 0.05) faced RB problems due to functional causes (34.18%), followed by pathological causes (28.01%), genital tract abnormalities (21.32%), and infectious causes (16.49%). Furthermore, the cows were remarkably (P < 0.001) affected in RB during the summer season and nutritional deficient diseases like milk fever (70%). Age (3-7 years) had a significant (P < 0.001) effect on the RB occurrence (90%) in crossbred cows. However, particular focus should be given to systematic breeding, balanced nutrition, artificial inseminator efficiency, and hygienic inseminating tools to reduce RB incidence in high-yielding crossbred cows.

Structures of drug-specific monoclonal antibodies bound to opioids and nicotine reveal a common mode of binding

Opioid-related fatal overdoses have reached epidemic proportions. Because existing treatments for opioid use disorders offer limited long-term protection, accelerating the development of newer approaches is critical. Monoclonal antibodies (mAbs) are an emerging treatment strategy that targets and sequesters selected opioids in the bloodstream, reducing drug distribution across the blood-brain barrier, thus preventing or reversing opioid toxicity. We previously identified a series of murine mAbs with high affinity and selectivity for oxycodone, morphine, fentanyl, and nicotine. To determine their binding mechanism, we used X-ray crystallography to solve the structures of mAbs bound to their respective targets, to 2.2 Å resolution or higher. Structural analysis showed a critical convergent hydrogen bonding mode that is dependent on a glutamic acid residue in the mAbs' heavy chain and a tertiary amine of the ligand. Characterizing drug-mAb complexes represents a significant step toward rational antibody engineering and future manufacturing activities to support clinical evaluation.

Preclinical Efficacy and Selectivity of Vaccines Targeting Fentanyl, Alfentanil, Sufentanil, and Acetylfentanyl in Rats

The ongoing public health emergency of opioid use disorders (OUD) and overdose in the United States is largely driven by fentanyl and its related analogues and has resulted in over 75 673 deaths in 2021. Immunotherapeutics such as vaccines have been investigated as a potential interventional strategy complementary to current pharmacotherapies to reduce the incidence of OUD and opioid-related overdose. Given the importance of targeting structurally distinct fentanyl analogues, this study compared a previously established lead conjugate vaccine (F₁-CRM) to a series of novel vaccines incorporating haptens derived from alfentanil and acetylfentanyl (F_{8, 9a, 9b, 10}), and evaluated their efficacy against drug-induced pharmacological effects in rats. While no vaccine tested provided significant protection against alfentanil, lead formulations were effective in reducing antinociception, respiratory depression, and bradycardia elicited by fentanyl, sufentanil, and acetylfentanyl. Compared with control, vaccination with F₁-CRM also reduced drug levels in the brain of rats challenged with lethal doses of fentanyl. These data further support investigation of F₁-CRM as a candidate vaccine against fentanyl and selected analogues.

Efficacy and Selectivity of Monovalent and Bivalent Vaccination Strategies to Protect against Exposure to Carfentanil, Fentanyl, and Their Mixtures in Rats

Drug-related fatal overdoses have significantly increased in the past decade due to the widespread availability of illicit fentanyl and other potent synthetic opioids such as carfentanil. Deliberate or accidental consumption or exposure to carfentanil, fentanyl, and their mixture induces respiratory depression and bradycardia that can be difficult to reverse with the opioid receptor antagonist naloxone. Vaccines offer a promising strategy to reduce the incidence of fatalities associated with fentanyl-related substances, as well as treatment for opioid use disorder (OUD). This study reports monovalent and bivalent vaccination strategies that elicit polyclonal antibody responses effective in protecting against the pharmacological actions of carfentanil, fentanyl, or carfentanil/fentanyl mixtures. Rats were prophylactically immunized with individual conjugate vaccines containing either carfentanil- or fentanyl-based haptens, or their combination in bivalent vaccine formulations, and then challenged with carfentanil, fentanyl, or their mixture. First, these studies identified a lead vaccine protective against carfentanil-induced antinociception, respiratory depression, and bradycardia. Then, efficacy against both carfentanil and fentanyl was achieved through bivalent vaccination strategies that combined lead anti-carfentanil and anti-fentanyl vaccines via either heterologous prime/boost or co-administration immunization regimens. These preclinical data support the development of vaccines as a viable strategy to prevent toxicity from exposure to excessive doses of carfentanil, fentanyl, or their mixtures.

Can Costus afer be used for co-treatment of COVID-19, its symptoms and comorbidities? A novel approach for combating the pandemic and implications for sub-Saharan Africa

Despite the huge loss of lives and massive disruption of the world economy by the COVID -19 pandemic caused by SARS -CoV-2, scientists are yet to come out with an effective therapeutic against this viral disease . Several vaccines have obtained 'emergency approval ', but difficulties are being faced in the even distribution of vaccines amongst high- and low- income countries . On top of it, comorbidities associated with COVID -19 like diabetes, hypertension and malaria can seriously impede the treatment of the main disease, thus increasing the fatality rate . This is more so in the context of sub -Saharan African and south Asian countries . Our objective was to demonstrate that a single plant containing different phytoconstituents may be used for treatment of COVID -19 and comorbidities . Towards initial selection of a plant, existing scientific literature was scanned for reported relevant traditional uses, phytochemicals and pharmacological activities of a number of plants and their phytoconstituents pertaining to treatment of COVID-19 symptoms and comorbidities. Molecular docking studies were then performed with phytochemicals of the selected plant and SARS-CoV-2 components - Mpro, and spike protein receptor binding domain and hACE2 interface using AutoDock V ina. We showed that crude extracts of an indigenous African plant, Costus afer having traditional antidiabetic and antimalarial uses, has phytochemicals with high binding affinities for Mpro, and /or spike protein receptor binding domain and hACE2 interface; the various phytochemicals with predicted high binding energies include aferoside C, dibutyl phthalate, nerolidol, suginal, and ± -terpinene, making them potential therapeutics for COVID -19. The results suggest that crude extracts and phytochemicals of C. afer can function as a treatment modality for COVID -19 and comorbidities like especially diabetes and malaria .

Sodium MR Neuroimaging

Sodium MR imaging has the potential to complement routine proton MR imaging examinations with the goal of improving diagnosis, disease characterization, and clinical monitoring in neurologic diseases. In the past, the utility and exploration of sodium MR imaging as a valuable clinical tool have been limited due to the extremely low MR signal, but with recent improvements in imaging techniques and hardware, sodium MR imaging is on the verge of becoming clinically realistic for conditions that include brain tumors, ischemic stroke, and epilepsy. In this review, we briefly describe the fundamental physics of sodium MR imaging tailored to the neuroradiologist, focusing on the basics necessary to understand factors that play into making sodium MR imaging feasible for clinical settings and describing current controversies in the field. We will also discuss the current state of the field and the potential future clinical uses of sodium MR imaging in the diagnosis, phenotyping, and therapeutic monitoring in neurologic diseases.

Risk Association, Clinical Presentation and Management of Uterine Leiomyoma

Uterine leiomyoma is a common gynecological problem throughout the world. As 50% hysterectomies in black and 40% in Australians are performed due to fibroid, in our country also it is assumed that about 40%-50% hysterectomies are done due to fibroid uterus. Thus leiomyoma constitute a major public health cost to the community in terms of outpatient attendance and hospital cost for surgery. This is a descriptive type of cross sectional study among 50 patients having leiomyoma of uterus in the department of Obs and Gynae, BSMMU hospital from March 2011 to August 2011. The objective of the study is to find out the risk associated with leiomyoma, to find out the common presenting features of uterine leiomyoma and to find out best options for management. Study results showed that 62% patients were in the age group 36-45 years, 48%patients were in para1-2 group, 32% patients used combined oral contraceptive pill for contraception. Sixty percent (60%) patients presented with progressive menorrhagia and palpable mass was found in 62% cases. About 46% patients had associated medical conditions like hypertension, diabetes, obesity. Total abdominal hysterectomy was done in 32% cases. TAH with unilateral or bilateral salpingoophorectomy was done in 40% cases. Myomectomy was done in 20% cases. There is a scope for large scale study about risk factors of uterine leiomyoma like obesity, diabetes mellitus, hypertension, use of hormonal contraceptive, racial differences, different treatment modalities etc. Treatment should be individualized. However in this connection a good referral system and good communication has got a tremendous contribution in the proper management of such problems.

Potential role of flavonoids against SARS-CoV-2 induced diarrhea

COVID-19, caused by the SARS-CoV-2 virus, can lead to massive inflammation in the gastrointestinal tract causing severe clinical symptoms. SARS-CoV-2 infects lungs after binding its spike proteins with alveolar angiotensin-converting enzyme 2 (ACE2), and it also triggers inflammation in the gastrointestinal tract. SARS-CoV-2 invades the gastrointestinal tract by interacting with Toll-like receptor-4 (TLR4) that induces the expression of ACE2. The influx of ACE2 facilitates cellular binding of more SARS-CoV-2 and causes massive gastrointestinal inflammation leading to diarrhea. Diarrhea prior to COVID-19 infection or COVID-19-induced diarrhea reportedly ends up in a poor prognosis for the patient. Flavonoids are part of traditional remedies for gastrointestinal disorders. Preclinical studies show that flavonoids can prevent infectious diarrhea. Recent studies show flavonoids can inhibit the multiplication of SARS-CoV-2. In combination with vitamin D, flavonoids possibly activate nuclear factor erythroid-derived-2-related factor 2 that downregulates ACE2 expression in cells. We suggest that flavonoids have the potential to prevent SARS-CoV-2 induced diarrhea.

In silico screening of Allium cepa phytochemicals for their binding abilities to SARS and SARS-CoV-2 3C-like protease and COVID-19 human receptor ACE-2

Corona virus SARS-CoV-2-induced viral disease (COVID-19) is a zoonotic disease that was initially transmitted from animals to humans. The virus surfaced towards the end of December 2019 in Wuhan, China where earlier SARS (Severe Acute Respiratory Syndrome) had also surfaced in 2003. Unlike SARS, SARS-CoV-2 (a close relative of the SARS virus) created a pandemic, and as of February 24 2021, caused 112,778,672 infections and 2,499,252 deaths world-wide. Despite the best efforts of scientists, no drugs against COVID-19 are yet in sight; five vaccines have received emergency approval in various countries, but it would be a difficult task to vaccinate twice the world population of 8 billion. The objective of the present study was to evaluate through in silico screening a number of phytochemicals in Allium cepa (onion) regarding their ability to bind to the main protease of COVID-19 known as the 3C-like protease or 3CL^pro, (PDB ID: 6LU7), 3CL^pro of SARS (PDB ID: 3M3V), and human angiotensin converting enzyme-2 (ACE-2), [PDB ID: 1R42], which functions as a receptor for entry of the virus into humans. Molecular docking (blind docking, that is docking not only against any target pocket) were done with the help of AutoDockVina. It was observed that of the twenty-two phytochemicals screened, twelve showed good binding affinities to the main protease of SARS-CoV-2. Surprisingly, the compounds also demonstrated good binding affinities to ACE-2. It is therefore very likely that the binding affinities shown by these compounds against both 3CL^pro and ACE-2 merit further study for their potential use as therapeutic agents.

Obstetric Outcome of Multiple Pregnancy in a Medical College Hospital

The Incidence of twin and high order multiple gestation has increased significantly over the past 15 years primarily because of the availability and increased use of ovulation inducing drugs and assisted reproductive technology. Both maternal and perinatal mortality and morbidity is higher in multiple pregnancy than in singleton pregnancy. Proposed study is designed to determine the incidence and obstetric outcome of multiple pregnancy which is a high-risk pregnancy in a tertiary referral hospital. The purpose of this study is to evaluate obstetric outcome of multiple pregnancy. This prospective observational study was carried out in the Department of Obs and Gynae, Mymensingh Medical College Hospital, Mymensingh from December 2011 to May 2012. Patients were selected by purposive way. In this study it was observed that incidence of twin pregnancy was 1.66% common age group 30-35 years (48%), common in multipara (74%), no pregnancy crossed EDD. Family history of twin was 32% and unknown etiology 58%. Most common maternal complication was preterm labour (60%). Commonest mode of delivery was LSCS (64%), incidence of perinatal mortality 15%, 36% baby had birth weight in between 2.1-2.5kg, all the baby requiring admission in neonatal unit. This prospective observational study revealed that perinatal mortality was high in our center, there was no maternal mortality.

Effect of Amniotomy on Outcome of Spontaneous Labour

Intentional artificial rupture of the amniotic membranes during labour, called amniotomy or 'breaking of the water's, is one of the most commonly performed procedures in modern obstetric and midwifery practice. The primary aim of amniotomy is to speed up uterine contractions and therefore shorten the length of labour. However there are concerns regarding unintended adverse effects on the woman and baby. A prospective observational study was conducted to determine the effectiveness and safety of routine procedure of amniotomy to shorten the duration of labour (prolonged or not) in Mymensingh Medical College & Hospital, Mymensingh, Bangladesh from July 2011 to December 2011. One hundred low-risk women with spontaneous onset of labour at term with singleton fetus in cephalic presentation and intact amniotic membranes and a cervical dilatation between 4 and 5cm were conventionally assigned to have amniotomy during the course of labour. Maternal demographics, duration of labour (prolonged or not), maternal and perinatal outcome were considered as major outcome. Majority (49.0%) of the patients belonged to 21-25 years age group and primigravida was predominant and most of them had middle socio-economic conditions. More the three-fourth (89.0%) of the patients had head engaged. Rh-positive and negative were found 96.0% and 4.0% respectively. The primigravidae required 10.07±2.17 hours in 1st stage of labour and had 1.51±0.5 hours duration of 2nd stage of labour. In case of multi-gravidae it was 6.07±2.06 hours in 1st stage of and 1±0.5 hours in 2nd stage of labour. There was a marked reduction of amniotomy-delivery interval time in this study, which was 3 hours 40 minutes and whereas mean cervical dilatation was 4cm during amniotomy. Almost three fourth (72.0%) cases delivered vaginally among which, with episiotomy in 49.0% and without episiotomy in 23.0%. Instrumental delivery was in 9.0% of which 4.0% by forceps, 5.0% by vaccum extraction and 14.0% underwent LUCS. Still birth was found 2.0%, asphyxiated 3.0% and prenatal death 1.0%. In terms of referral to neonatal care unit it was found that 7.0% were asphyxiated. Asphyxia and low APGAR score was 4.0%, low birth weight 9.0%, instrumental delivery was 5.0%, Rh incompatibility was 2.0%. Only 1.0% babies needed admission to neonatal care unit and were intubated. So, Amniotomy significantly reduced the duration of the first stage of labour without affecting the oxytocin requirement, the rate of caesarean section and newborn outcome.

Imidazodiazepine Anticonvulsant, KRM-II-81, Produces Novel, Non-diazepam-like Antiseizure Effects

The need for improved medications for the treatment of epilepsy and chronic pain is essential. Epileptic patients typically take multiple antiseizure drugs without complete seizure freedom, and chronic pain is not fully managed with current medications. A positive allosteric modulator (PAM) of α2/3-containing GABA_A receptors (5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazole[1,5-α][1,4]diazepin-3-yl) oxazole or KRM-II-81 (8) is a lead compound in a series of imidazodiazepines. We previously reported that KRM-II-81 produces broad-based anticonvulsant and antinociceptive efficacy in rodent models and provides a wider margin over motoric side effects than that of other GABA_A receptor PAMs. The present series of experiments was designed to fill key missing gaps in prior preclinical studies assessing whether KRM-II-81 could be further differentiated from nonselective GABA_A receptor PAMs using the anticonvulsant diazepam (DZP) as a comparator. In multiple chemical seizure provocation models in mice, KRM-II-81 was either equally or more efficacious than DZP. Most strikingly, KRM-II-81 but not DZP blocked the development of seizure sensitivity to the chemoconvulsants cocaine and pentylenetetrazol in seizure kindling models. These and predecessor data have placed KRM-II-81 into consideration for clinical development requiring the manufacture of kilogram amounts of good manufacturing practice material. We describe here a novel synthetic route amenable to kilogram quantity production. The new biological and chemical data provide key steps forward in the development of KRM-II-81 (8) as an improved treatment option for patients suffering from epilepsy.

The Positive Allosteric Modulator of α2/3-Containing GABAA Receptors, KRM-II-81, Is Active in Pharmaco-Resistant Models of Epilepsy and Reduces Hyperexcitability after Traumatic Brain Injury

The imidizodiazepine, 5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazo[1,5-a][1,4]diazepin-3-yl)oxazole (KRM-II-81), is selective for α2/3-containing GABAA receptors. KRM-II-81 dampens seizure activity in rodent models with enhanced efficacy and reduced motor-impairment compared with diazepam. In the present study, KRM-II-81 was studied in assays designed to detect antiepileptics with improved chances of impacting pharmaco-resistant epilepsies. The potential for reducing neural hyperactivity weeks after traumatic brain injury was also studied. KRM-II-81 suppressed convulsions in corneal-kindled mice. Mice with kainate-induced mesial temporal lobe seizures exhibited spontaneous recurrent hippocampal paroxysmal discharges that were significantly reduced by KRM-II-81 (15 mg/kg, orally). KRM-II-81 also decreased convulsions in rats undergoing amygdala kindling in the presence of lamotrigine (lamotrigine-insensitive model) (ED50 = 19 mg/kg, i.p.). KRM-II-81 reduced focal and generalized seizures in a kainate-induced chronic epilepsy model in rats (20 mg/kg, i.p., three times per day). In mice with damage to the left cerebral cortex by controlled-cortical impact, enduring neuronal hyperactivity was dampened by KRM-II-81 (10 mg/kg, i.p.) as observed through in vivo two-photon imaging of layer II/III pyramidal neurons in GCaMP6-expressing transgenic mice. No notable side effects emerged up to doses of 300 mg/kg KRM-II-81. Molecular modeling studies were conducted: docking in the binding site of the α1β3γ2L GABAA receptor showed that replacing the C8 chlorine atom of alprazolam with the acetylene of KRM-II-81 led to loss of the key interaction with α1His102, providing a structural rationale for its low affinity for α1-containing GABAA receptors compared with benzodiazepines such as alprazolam. Overall, these findings predict that KRM-II-81 has improved therapeutic potential for epilepsy and post-traumatic epilepsy. SIGNIFICANCE STATEMENT: We describe the effects of a relatively new orally bioavailable small molecule in rodent models of pharmaco-resistant epilepsy and traumatic brain injury. KRM-II-81 is more potent and generally more efficacious than standard-of-care antiepileptics. In silico docking experiments begin to describe the structural basis for the relative lack of motor impairment induced by KRM-II-81. KRM-II-81 has unique structural and anticonvulsant effects, predicting its potential as an improved antiepileptic drug and novel therapy for post-traumatic epilepsy.

The value of human epileptic tissue in the characterization and development of novel antiepileptic drugs: The example of CERC-611 and KRM-II-81

The need for improved antiepileptics is clearly mandated despite the existence of multiple existing medicines from different chemical and mechanistic classes. Standard of care agents do not fully control epilepsies and have a variety of side-effect and safety issues. Patients typically take multiple antiepileptic drugs and yet many continue to have seizures. Antiepileptic-unresponsive seizures are life-disrupting and life-threatening. One approach to seizure control is surgical resection of affected brain tissue and associated neural circuits. Although non-human brain studies can provide insight into novel antiepileptic mechanisms, human epileptic brain is the bottom-line biological substrate. Human epileptic brain can provide definitive information on the presence or absence of the putative protein targets of interest in the patient population, the potential changes in these proteins in the epileptic state, and the engagement of novel molecules and their functional impact in target tissue. In this review, we discuss data on two novel potential antiepileptic drugs. CERC-611 (LY3130481) is an AMPA receptor antagonist that selectively blocks AMPA receptors associated with the auxiliary protein TARP γ-8 and is in clinical development. KRM-II-81 is a positive allosteric modulator of GABA_A receptors selectively associated with protein subunits α2 and α 3. Preclinical data on these compounds argue that patient-based biological data increase the probability that a newly discovered molecule will translate its antiepileptic potential to patients.

The α2,3-selective potentiator of GABAA receptors, KRM-II-81, reduces nociceptive-associated behaviors induced by formalin and spinal nerve ligation in rats

Clinical evidence indicates that positive allosteric modulators (PAMs) of GABAA receptors have analgesic benefit in addition to efficacy in anxiety disorders. However, the utility of GABAA receptor PAMs as analgesics is compromised by the central nervous system side effects of non-selective potentiators. A selective potentiator of GABAA receptors associated with α2/3 subunits, KRM-II-81(5-(8-ethynyl-6-(pyridin-2-yl)-4H-benzo[f]imidazo[1,5-a][1,4]diazepin-3-yl)oxazole), has demonstrated anxiolytic, anticonvulsant, and antinociceptive effects in rodents with reduced motoric side effects. The present study evaluated the potential of KRM-II-81 as a novel analgesic. Oral administration of KRM-II-81 attenuated formalin-induced flinching; in contrast, diazepam was not active. KRM-II-81 attenuated nociceptive-associated behaviors engendered by chronic spinal nerve ligation (L5/L6). Diazepam decreased locomotion of rats at the dose tested in the formalin assay (10 mg/kg) whereas KRM-II-81 produced small decreases that were not dose-dependent (10-100 mg/kg). Plasma and brain levels of KRM-II-81 were used to demonstrate selectivity for α2/3- over α1-associated GABAA receptors and to define the degree of engagement of these receptors. Plasma and brain concentrations of KRM-II-81 were positively-associated with analgesic efficacy. GABA currents from isolated rat dorsal-root ganglion cultures were potentiated by KRM-II-81 with an ED50 of 32 nM. Measures of respiratory depression were reduced by alprazolam whereas KRM-II-81 was either inactive or produced effects with lower potency and efficacy. These findings add to the growing body of data supporting the idea that α2/3-selective GABAA receptor PAMs will have efficacy and tolerability as pain medications including those for neuropathic pain. Given their predicted anxiolytic effects, α2/3-selective GABAA receptor PAMs offer an additional inroad into the management of pain.

GABAA Receptor Subtypes and the Abuse-Related Effects of Ethanol in Rhesus Monkeys: Experiments with Selective Positive Allosteric Modulators

BACKGROUND

Previous studies have investigated α1GABAA and α5GABAA receptor mechanisms in the behavioral effects of ethanol (EtOH) in monkeys. However, genetic studies in humans and preclinical studies with mutant mice suggest a role for α2GABAA and/or α3GABAA receptors in the effects of EtOH. The development of novel positive allosteric modulators (PAMs) with functional selectivity (i.e., selective efficacy) at α2GABAA and α3GABAA receptors allows for probing of these subtypes in preclinical models of the discriminative stimulus and reinforcing effects of EtOH in rhesus macaques.

METHODS

In discrimination studies, subjects were trained to discriminate EtOH (2 g/kg, intragastrically) from water under a fixed-ratio (FR) schedule of food delivery. In oral self-administration studies, subjects were trained to self-administer EtOH (2% w/v) or sucrose (0.3 to 1% w/v) under an FR schedule of solution availability.

RESULTS

In discrimination studies, functionally selective PAMs at α2GABAA and α3GABAA (HZ-166) or α3GABAA (YT-III-31) receptors substituted fully (maximum percentage of EtOH-lever responding ≥80%) for the discriminative stimulus effects of EtOH without altering response rates. Full substitution for EtOH also was engendered by a nonselective PAM (triazolam), an α5GABAA -preferring PAM (QH-ii-066) and a PAM at α2GABAA , α3GABAA , and α5GABAA receptors (L-838417). A partial (MRK-696) or an α1GABAA -preferring (zolpidem) PAM only engendered partial substitution (i.e., ~50 to 60% EtOH-lever responding). In self-administration studies, pretreatments with the functionally selective PAMs at α2GABAA and α3GABAA (XHe-II-053 and HZ-166) or α3GABAA (YT-III-31 and YT-III-271) receptors increased EtOH, but not sucrose, drinking at doses that had few, or no, observable sedative-motor effects.

CONCLUSIONS

Our results confirm prior findings regarding the respective roles of α1GABAA and α5GABAA receptors in the discriminative stimulus effects of EtOH and, further, suggest a key facilitatory role for α3GABAA and potentially α2GABAA receptors in several abuse-related effects of EtOH in monkeys. Moreover, they reveal a potential role for these latter subtypes in EtOH's sedative effects.