Phenols and GABAA receptors: from structure and molecular mechanisms action to neuropsychiatric sequelae.

γ-Aminobutyric acid type A receptors (GABAARs) are members of the pentameric ligand-gated ion channel (pLGIC) family, which are widespread throughout the invertebrate and vertebrate central nervous system. GABAARs are engaged in short-term changes of the neuronal concentrations of chloride (Cl-) and bicarbonate (HCO3 -) ions by their passive permeability through the ion channel pore. GABAARs are regulated by various structurally diverse phenolic substances ranging from simple phenols to complex polyphenols. The wide chemical and structural variability of phenols suggest similar and different binding sites on GABAARs, allowing them to manifest themselves as activators, inhibitors, or allosteric ligands of GABAAR function. Interest in phenols is associated with their great potential for GABAAR modulation, but also with their subsequent negative or positive role in neurological and psychiatric disorders. This review focuses on the GABAergic deficit hypotheses during neurological and psychiatric disorders induced by various phenols. We summarize the structure-activity relationship of general phenol groups concerning their differential roles in the manifestation of neuropsychiatric symptoms. We describe and analyze the role of GABAAR subunits in manifesting various neuropathologies and the molecular mechanisms underlying their modulation by phenols. Finally, we discuss how phenol drugs can modulate GABAAR activity via desensitization and resensitization. We also demonstrate a novel pharmacological approach to treat neuropsychiatric disorders via regulation of receptor phosphorylation/dephosphorylation.

Comparison of tympanometric volume measurement with temporal bone CT findings in the assessment of mastoid bone pneumatization in chronic otitis media patients.

OBJECTIVE: Since mastoid bone aeration is a pressure buffer for the middle ear, it can be accepted as a prognostic factor for tympanoplasty. Temporal bone computed tomography (TBCT) is a primary method for estimating mastoid aeration. However, due to the risk of radiation and its high cost, there is a need for a more straightforward, faster, and more reliable method in non-complicated chronic otitis media cases (COM). Tympanometric volume measurement might be used for this purpose. This study investigated tympanometric volume measurement's reliability in showing mastoid bone aeration by comparing tympanometric volume measurement with TBCT aeration grading. PATIENTS AND METHODS: Preoperative tympanometric volume measurements were performed in patients who underwent audiological examination and temporal computerized tomography (CT) with the diagnosis of COM and sequela of COM without discharge for the last three months and were indicated for surgery. CT was classified into six grades: grade 0: there is no aeration, sclerotic mastoid; grade 1: pneumatization only in the mastoid antrum; grade 2: <25% pneumatization; grade 3: 25-50% pneumatization; grade 4: >50 pneumatization, grade 5: full pneumatization. Averages of tympanometric volume values were determined according to CT degrees. RESULTS: 48 left and 52 right ears (n: 100) of 81 patients, 24 females and 57 males, were included in the study. The mean age was 37.69±13.38. Mastoid pneumatization grades of patients were 32 grade 0, 23 grade 1, 16 grade 2, 14 grade 3, 11 grade 4, and 4 grade 5, respectively. Each grade's mean tympanometric volume (mL) was grade 0: 1.1594, grade 1: 1.6991, grade 2: 2.2250, grade 3: 3.0471, grade 4: 4.0327, and grade 5: 2.9775. CONCLUSIONS: There is a statistically significant relationship between tympanometrically measured ear volume and mastoid degrees of pneumatization on temporal bone tomography. As the degree of mastoid aeration increases, the tympanometric volume also increases. According to the results of this study, tympanometric air volume can be used reliably in the preoperative evaluation of mastoid bone aeration in cases of simple COM without ear drainage.

Protein Corona Attenuates the Targeting of Antitumor Sialyl Lewis X-Decorated Liposomes to Vascular Endothelial Cells under Flow Conditions.

Previously, we showed in the human umbilical vein endothelial cells (HUVECs) model that a liposome formulation of melphalan lipophilic prodrug (MlphDG) decorated with selectin ligand tetrasaccharide Sialyl Lewis X (SiaLeX) undergoes specific uptake by activated cells and in an in vivo tumor model causes a severe antivascular effect. Here, we cultured HUVECs in a microfluidic chip and then applied the liposome formulations to study their interactions with the cells in situ under hydrodynamic conditions close to capillary blood flow using confocal fluorescent microscopy. The incorporation of 5 to 10% SiaLeX conjugate in the bilayer of MlphDG liposomes increased their consumption exclusively by activated endotheliocytes. The increase of serum concentration from 20 to 100% in the flow resulted in lower liposome uptake by the cells. To elucidate the possible roles of plasma proteins in the liposome-cell interactions, liposome protein coronas were isolated and analyzed by shotgun proteomics and immunoblotting of selected proteins. Proteomic analysis showed that a gradual increase in SiaLeX content correlated with the overall enrichment of the liposome-associated proteins with several apolipoproteins, including the most positively charged one, ApoC1, and serum amyloid A4, associated with inflammation, on the one hand, and a decrease in the content of bound immunoglobulins, on the other. The article discusses the potential interference of the proteins in the binding of liposomes to selectins of endothelial cells.

Investigation of Platelet Apoptosis in Patients after Surgical Myocardial Revascularization.

Platelets are one of the main participants in vascular accidents in cases of coronary heart disease (CHD). In this study, we sought to detect platelet apoptosis in patients with coronary artery disease who underwent scheduled myocardial revascularization surgery. To identify apoptotic events, we analyzed phosphatidylserine (PS) expression on the surface of platelets and mitochondrial membrane potential (ΔΨm) by flow cytometry in two groups of 30 patients aged 45-60 years: Group 1-patients before myocardial revascularization surgery and group 2-patients after myocardial revascularization surgery. The control group consisted of 10 healthy volunteers aged 45-60 years. According to our data, the percentage levels of PS expression in patients greatly decreased after surgery. We confirmed platelet apoptosis by recording depolarization of ΔΨm in pre- and postoperative patients. ΔΨm readings were considerably improved after surgery. Our data indicated that the functional parameters of platelets in patients with coronary heart disease differed from the characteristics of platelets in patients who underwent myocardial revascularization, and from those of patients in a control group. Future studies of platelet phenotypic characteristics and platelet apoptosis biomarkers should greatly advance our understanding of the pathophysiology of coronary heart disease, and further promote the development of methods for predicting adverse outcomes after surgery.

Zinc Inhibits the GABAAR/ATPase during Postnatal Rat Development: The Role of Cysteine Residue.

Zinc ions (Zn2+) are concentrated in various brain regions and can act as a neuromodulator, targeting a wide spectrum of postsynaptic receptors and enzymes. Zn2+ inhibits the GABAARs, and its potency is profoundly affected by the subunit composition and neuronal developmental stage. Although the extracellular amino acid residues of the receptor's hetero-oligomeric structure are preferred for Zn2+ binding, there are intracellular sites that, in principle, could coordinate its potency. However, their role in modulating the receptor function during postembryonic development remains unclear. The GABAAR possesses an intracellular ATPase that enables the energy-dependent anion transport via a pore. Here, we propose a mechanistic and molecular basis for the inhibition of intracellular GABAAR/ATPase function by Zn2+ in neonatal and adult rats. The enzymes within the scope of GABAAR performance as Cl-ATPase and then as Cl-, HCO3-ATPase form during the first week of postnatal rat development. In addition, we have shown that the Cl-ATPase form belongs to the ß1 subunit, whereas the ß3 subunit preferably possesses the Cl-, HCO3-ATPase activity. We demonstrated that a Zn2+ with variable efficacy inhibits the GABAAR as well as the ATPase activities of immature or mature neurons. Using fluorescence recording in the cortical synaptoneurosomes (SNs), we showed a competitive association between Zn2+ and NEM in parallel changes both in the ATPase activity and the GABAAR-mediated Cl- and HCO3- fluxes. Finally, by site-directed mutagenesis, we identified in the M3 domain of ß subunits the cysteine residue (C313) that is essential for the manifestation of Zn2+ potency.

Learning Curve for Flow Diversion of Posterior Circulation Aneurysms: A Long-Term International Multicenter Cohort Study.

BACKGROUND AND PURPOSE: Flow diversion has gradually become a standard treatment for intracranial aneurysms of the anterior circulation. Recently, the off-label use of the flow diverters to treat posterior circulation aneurysms has also increased despite initial concerns of rupture and the suboptimal results. This study aimed to explore the change in complication rates and treatment outcomes across time for posterior circulation aneurysms treated using flow diversion and to further evaluate the mechanisms and variables that could potentially explain the change and outcomes. MATERIALS AND METHODS: A retrospective review using a standardized data set at multiple international academic institutions was performed to identify patients with ruptured and unruptured posterior circulation aneurysms treated with flow diversion during a decade spanning January 2011 to January 2020. This period was then categorized into 4 intervals. RESULTS: A total of 378 procedures were performed during the study period. Across time, there was an increasing tendency to treat more vertebral artery and fewer large vertebrobasilar aneurysms (P = .05). Moreover, interventionalists have been increasingly using fewer overlapping flow diverters per aneurysm (P = .07). There was a trend toward a decrease in the rate of thromboembolic complications from 15.8% in 2011-13 to 8.9% in 2018-19 (P = .34). CONCLUSIONS: This multicenter experience revealed a trend toward treating fewer basilar aneurysms, smaller aneurysms, and increased usage of a single flow diverter, leading to a decrease in the rate of thromboembolic and hemorrhagic complications.

Effects of total knee arthroplasty on balance and fall risk in elderly patients with severe gonarthrosis: An age- and sex-matched comparative study.

Background: Falls are a severe cause of morbidity and mortality in elderly patients, and gonarthrosis causes a tendency to fall. Total knee arthroplasty (TKA) is a widely used successful surgical procedure for end-stage gonarthrosis. Aims: To investigate whether there is a difference in the frequency of falls, balance and fall risk, and clinical and radiological results in patients with end-stage gonarthrosis with and without TKA. Patients and Methods: This was a single-center, retrospective, case-control study with age- and gender-matched groups. A total of 100 patients over 60 years of age, with end-stage gonarthrosis and who met the inclusion criteria were included in the study. Fall risk was analyzed using the Berg Balance Scale (BBS), TUG tests, and the ITAKI Fall Risk Test. Knee varus angles were measured using standing long-leg radiographs, and radiological gonarthrosis grading was performed. Pain levels and quality of life were assessed using the VAS and WOMAC. Each patient's knee extensor muscle strength and range of motion were measured. Results: WOMAC, ITAKI, TUG test, and VAS scores were significantly higher in the control group than in the TKA group. BBS scores were significantly lower in the control group. Although the number of falls was high in the control group, there was no statistically significant difference between the two groups. Conclusion: The results of this study showed that total knee arthroplasty provided statistically significant improvement in the clinical, radiological, and fall risk results of the patients. Although there was a decrease in the frequency of falls compared to the control group, it was statistically insignificant. In addition, in our study, it was evaluated that the most important risk factor for falling was advanced age.

Carbon-oxygen surface formation enhances secondary electron yield in Cu, Ag and Au.

First-principles calculations coupled with Monte Carlo simulations are used to probe the role of a surface CO monolayer formation on secondary electron emission (SEE) from Cu, Ag, and Au (110) materials. It is shown that formation of such a layer increases the secondary electron emission in all systems. Analysis of calculated total density of states (TDOS) in Cu, Ag, and Au, and partial density of states (PDOS) of C and O confirm the formation of a covalent type bonding between C and O atoms. It is shown that such a bond modifies the TDOS and extended it to lower energies, which is then responsible for an increase in the probability density of secondary electron generation. Furthermore, a reduction in inelastic mean free path is predicted for all systems. Our predicted results for the secondary electron yield (SEY) compare very favorably with experimental data in all three materials, and exhibit increases in SEY. This is seen to occur despite increases in the work function for Cu, Ag, and Au. The present analysis can be extended to other absorbates and gas atoms at the surface, and such analyses will be present elsewhere.

Physiological Role of ATPase for GABAA Receptor Resensitization.

γ-Aminobutyric acid type A receptors (GABAARs) mediate primarily inhibitory synaptic transmission in the central nervous system. Following fast-paced activation, which provides the selective flow of mainly chloride (Cl-) and less bicarbonate (HCO3-) ions via the pore, these receptors undergo desensitization that is paradoxically prevented by the process of their recovery, referred to as resensitization. To clarify the mechanism of resensitization, we used the cortical synaptoneurosomes from the rat brain and HEK 293FT cells. Here, we describe the effect of γ-phosphate analogues (γPAs) that mimic various states of ATP hydrolysis on GABAAR-mediated Cl- and HCO3- fluxes in response to the first and repeated application of the agonist. We found that depending on the presence of bicarbonate, opened and desensitized states of the wild or chimeric GABAARs had different sensitivities to γPAs. This study presents the evidence that recovery of neuronal Cl- and HCO3- concentrations after desensitization is accompanied by a change in the intracellular ATP concentration via ATPase performance. The transition between the desensitization and resensitization states was linked to changes in both conformation and phosphorylation. In addition, the chimeric ß3 isoform did not exhibit the desensitization of the GABAAR-mediated Cl- influx but only the resensitization. These observations lend a new physiological significance to the ß3 subunit in the manifestation of GABAAR resensitization.

Serological exposure in Bactrian and dromedary camels in Kazakhstan to a MERS or MERS-like coronavirus.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a camel-borne zoonotic virus endemic across Eastern Africa and the Middle East, with evidence of circulation in Bangladesh and Mongolia. To determine if MERS-CoV was present in Kazakhstan, in 2017-2018, we collected swabs and sera from Bactrian camels (n = 3124) and dromedary (n = 5083). The total seropositivity was 0.54% in Bactrian camels and 0.24% in dromedaries; however, we did not detect MERS-CoV RNA in swab samples. There was no difference in the probability of infection between species or sex, but younger camels had a higher probability of being seropositive, suggesting a recent introduction of the virus to Kazakhstan. The infection of both camel species indicates that they both may play a role as natural reservoirs. These results reinforce the need for continual surveillance, especially at the camel-human interface to understand the risk of zoonotic exposure.

The unilateral frontotemporal approach for large and giant olfactory groove meningioma: Experience with 18 consecutive patients.

AIM: Although the bifrontal approach used to be recommended for large olfactory groove meningioma (OGM), recent studies showed that large OGMs can also be resected safely via unilateral approaches. The present study aimed to discuss reasons for preferring a unilateral frontotemporal approach (UFTA), and the technical nuances and results of the UFTA, based on 18 cases. MATERIAL AND METHODS: The clinical and surgical data of patients who had been operated on for large (4-6cm) or giant (>6cm) OGM via a UFTA between 2011 and 2018 were retrospectively collected. RESULTS: In all, 18 patients were included. All tumors were compatible with a diagnosis of OGM in the light of peri-operative examinations. 11 cases (61%) were large and 7 (39%) giant OGM; mean diameter was 6.1cm (range, 4-10cm). Resection extent was Simpson grade II in 14 cases (78%), grade III in 1 (5%), and grade IV in 3 (17%). Sixteen cases (89%) had no peri-operative complications, while 2 patients (11%) showed cerebrospinal fluid leakage and hemorrhagic deposition in the surgical area. There were no new neurological deficits nor deaths. CONCLUSION: The UFTA for OGM is a relatively safe and effective approach, ensuring a high total removal rate with low mortality and morbidity. This study, with a reasonable number of patients, is one of the few in the literature on the outcome of this approach.

Effects of elimination diets and clinical findings on mothers' anxiety in infants with food allergy with non-life-threatening reactions.

Summary: Background. In food allergies (FA), the current treatment is eliminating the responsible food from the diet until tolerance develops. We aimed to determine the effects of the mother's elimination diets and clinical findings on the mothers' anxiety in infants with food allergy (FA) with non-life-threatening reactions. Methods. Our study included 100 infants with FA and 35 healthy infants as control. A data form was prepared to collect information about the infants' and their mothers' socio-demographic characteristics, clinical findings, features of the mother's elimination diet, and FA-related internet search. State-Trait Anxiety Inventory (STAI) was applied to all mothers. Results. The STAI (state anxiety and trait anxiety) scores of the mothers of the infants with FA were higher than the control group (p less than 0.001, p = 0.001, respectively). Of the infants with FA, 51% had food protein-induced allergic proctocolitis (FPIAP), 29% had atopic dermatitis (AD), 20% had urticaria-angioedema (U/AE). It was found that state anxiety scores were higher in mothers whose child had FPIAP, who had multiple food eliminations, who followed the allergy groups on social media, and who made the elimination diet herself (p = 0.008, p = 0.048, p less than 0.001, p = 0.001, respectively). Conclusions. The state anxiety and trait anxiety of the mothers of the infants with FA were higher than the control group, and the state anxiety scores were higher especially in the mothers of infants with FPIAP and multiple food elimination.

Intricacies of GABAA Receptor Function: The Critical Role of the ß3 Subunit in Norm and Pathology.

Neuronal intracellular chloride ([Cl-]i) is a key determinant in γ-aminobutyric acid type A (GABA)ergic signaling. γ-Aminobutyric acid type A receptors (GABAARs) mediate both inhibitory and excitatory neurotransmission, as the passive fluxes of Cl- and HCO3- via pores can be reversed by changes in the transmembrane concentration gradient of Cl-. The cation-chloride co-transporters (CCCs) are the primary systems for maintaining [Cl-]i homeostasis. However, despite extensive electrophysiological data obtained in vitro that are supported by a wide range of molecular biological studies on the expression patterns and properties of CCCs, the presence of ontogenetic changes in [Cl-]i-along with the consequent shift in GABA reversal potential-remain a subject of debate. Recent studies showed that the ß3 subunit possesses properties of the P-type ATPase that participates in the ATP-consuming movement of Cl- via the receptor. Moreover, row studies have demonstrated that the ß3 subunit is a key player in GABAAR performance and in the appearance of serious neurological disorders. In this review, we discuss the properties and driving forces of CCCs and Cl-, HCO3-ATPase in the maintenance of [Cl-]i homeostasis after changes in upcoming GABAAR function. Moreover, we discuss the contribution of the ß3 subunit in the manifestation of epilepsy, autism, and other syndromes.

Ectopic GABAA receptor ß3 subunit determines Cl- / HCO3- -ATPase and chloride transport in HEK 293FT cells.

Neuronal intracellular chloride concentration ([Cl- ]i ) is a crucial determinant of transmission mediated by the γ-aminobutyric acid type A receptor (GABAA R), which subserves synaptic and extrasynaptic inhibition as well as excitation. The Cl- ion is the main carrier of charge through the GABAA R; however, bicarbonate ions ( HCO3- ) flowing in the opposite direction can also contribute to the net current. The direction of Cl- and HCO3- fluxes is determined by the underlying electrochemical gradient, which is controlled by Cl- transporters and channels. Accumulating evidence suggests that active mechanisms of chloride transport across the GABAA R pore can underlie the regulation of [Cl- ]i . Measurement of Cl- / HCO3- -ATPase activity and Cl- transport in HEK 293FT cells expressing homomeric or heteromeric GABAA R ensembles (α2, ß3, or γ2) with fluorescent dye for chloride demonstrated that receptor subtypes containing the ß3 subunit show enzymatic activity and participate in GABA-mediated or ATP-dependent Cl- transport. GABA-mediated flow of Cl- ions into and out of the cells occurred for a short time period but then rapidly declined. However, Cl- ion flux was stabilized for a long time period in the presence of HCO3- ions. The reconstituted ß3 subunit isoform, purified as a fusion protein, confirmed that ß3 is critical for ATPase; however, only the triplet variant showed the full receptor function. The high sensitivity of the enzyme to γ-phosphate inhibitors led us to postulate that the ß3 subunit is catalytic. Our discovery of a GABAA R type that requires ATP consumption for chloride movement provides new insight into the molecular mechanisms of inhibitory signaling.

Occurrence of a human-associated microbial source tracking marker and its relationship with faecal indicator bacteria in an urban estuary.

One of the main impacts of urban sprawl in rapidly growing countries has been contamination of coastal environments by waterborne pathogens, posing a critical risk to ecosystem and human health. Microbial source tracking (MST) has been a robust tool to identify the origin of these pathogens globally. This study compared the occurrence of a human-associated Bacteroides marker (BT-α) with faecal indicator bacteria (FIB) in an urban estuary (Golden Horn, Istanbul, Turkey). Faecal coliform (culture method), enterococci (both culture and qPCR method) concentrations and physicochemical variables were compared with the BT-α concentrations in monthly collected samples for a year (n = 108). Enterococci concentrations detected by culture and qPCR were positively correlated (r = 0·86, P < 0·01) suggesting that qPCR can be an alternative method for monitoring. BT-α marker was positive for 30% of the samples and positively correlated with enterococci (r = 0·61 and r = 0·64 for culture and qPCR methods respectively, P < 0·01). Rainfall had a moderate positive correlation with all faecal/MST indicators suggesting combined sewer overflows also severely impacted estuarine water quality. The high FIB and BT-α concentrations at upper estuary suggested that faecal pollution mainly originated from the peri-urban settlements around two creeks entering the estuary.

Transcriptomic changes triggered by ouabain in rat cerebellum granule cells: Role of α3- and α1-Na+,K+-ATPase-mediated signaling.

It was shown previously that inhibition of the ubiquitous α1 isoform of Na+,K+-ATPase by ouabain sharply affects gene expression profile via elevation of intracellular [Na+]i/[K+]i ratio. Unlike other cells, neurons are abundant in the α3 isoform of Na+,K+-ATPase, whose affinity in rodents to ouabain is 104-fold higher compared to the α1 isoform. With these sharp differences in mind, we compared transcriptomic changes in rat cerebellum granule cells triggered by inhibition of α1- and α3-Na+,K+-ATPase isoforms. Inhibition of α1- and α3-Na+,K+-ATPase isoforms by 1 mM ouabain resulted in dissipation of transmembrane Na+ and K+ gradients and differential expression of 994 transcripts, whereas selective inhibition of α3-Na+,K+-ATPase isoform by 100 nM ouabain affected expression of 144 transcripts without any impact on the [Na+]i/[K+]i ratio. The list of genes whose expression was affected by 1 mM ouabain by more than 2-fold was abundant in intermediates of intracellular signaling and transcription regulators, including augmented content of Npas4, Fos, Junb, Atf3, and Klf4 mRNAs, whose upregulated expression was demonstrated in neurons subjected to electrical and glutamatergic stimulation. The role [Na+]i/[K+]i-mediated signaling in transcriptomic changes involved in memory formation and storage should be examined further.

Discovery and Characterization of Novel Bat Coronavirus Lineages from Kazakhstan.

Coronaviruses are positive-stranded RNA viruses that infect a variety of hosts, resulting in a range of symptoms from gastrointestinal illness to respiratory distress. Bats are reservoirs for a high diversity of coronaviruses, and focused surveillance detected several strains genetically similar to MERS-coronavirus, SARS-coronavirus, and the human coronaviruses 229E and NL63. The bat fauna of central Asia, which link China to eastern Europe, are relatively less studied than other regions of the world. Kazakhstan is the world's ninth largest country; however, little is understood about the prevalence and diversity of bat-borne viruses. In this study, bat guano was collected from bat caves in three different sites of southern Kazakhstan that tested positive for coronaviruses. Our phylogenetic reconstruction indicates these are novel bat coronaviruses that belong to the genus Alphacoronavirus. In addition, two distinct lineages of Kazakhstan bat coronaviruses were detected. Both lineages are closely related to bat coronaviruses from China, France, Spain, and South Africa, suggesting that co-circulation of coronaviruses is common in multiple bat species with overlapping geographical distributions. Our study highlights the need for collaborative efforts in understudied countries to increase integrated surveillance capabilities toward better monitoring and detection of infectious diseases.

Determination of Blood Plasma Aminothiols Using Derivatization-enhanced Capillary Transient Isotachophoresis.

A sensitive capillary electrophoresis method was developed for the determination of aminothiol (cysteine, homocysteine, and glutathione) total levels in human blood plasma. Analytes were derivatized with Ellman's reagent (5,5'-dithiobis(2-nitrobenzoic acid)) after reduction with dithiothreitol. Liquid-liquid extraction was applied to purify the samples and concentrate the analytes. Total analysis time was 7.5 min using a silica capillary (50 µm i.d.; effective separation length 23.5 cm). Electrophoretic separation was performed using 50 mM citric acid with 20 mM triethanolamine (pH 3) containing 2% Ficoll 400. Detection limit was 0.8 µM for glutathione and 0.3 µM for both cysteine and homocysteine. Accuracy was 94 - 107%, repeatability and reproducibility were ca. 2.7 - 3.5 and 2.5 - 6.5%, respectively.