GABAergic modification of myopic and hyperopic ocular tissue effects on scleral fibroblast growth

Purpose: Myopia is a common eye disorder affecting up to 90% of children in South East Asia and 30% of the population worldwide. Myopia of high severity is a leading cause of blindness around the world (4th to 5th most common). Changes and remodelling of the sclera i.e. increase cellular proliferation & increase protein synthesis within scleral cells (↑ scleral DNA) and thinning and lose of extracellular matrix of sclera (↓ scleral GAG synthesis) have been linked to myopic eye growth in animal models. Signals acting on the sclera are thought to originate in the retina, and are modulated by the retinal pigment epithelium (RPE) with limited evidence suggesting that the RPE can modify scleral cell growth in culture. However, the mechanism of retinal signal transmission and the role of posterior eye cup tissue, including the RPE, in mediating changes in scleral fibroblast growth during myopia development are unclear. Retinal transmitter systems are critically involved in pathways regulating eye growth, which ultimately lead to alterations in the sclera if eye size is to change. A dopaminergic agonist and muscarinic antagonists decrease the proliferation of scleral chondrocytes when co-cultured with chick’s retinal pigment epithelium (RPE). GABA receptors have recently been localised to chick sclera. We therefore hypothesised that posterior eye cup tissue from myopic eyes would stimulate and from hyperopic eyes would inhibit growth of scleral fibroblasts in vitro and that GABAergic agents could directly interact with scleral cells or indirectly modify the effects of myopic and hyperopic posterior eye cup tissue on scleral fibroblast growth. Method: Fibroblastic cells obtained from 8-day-old chick sclera were used to establish cell banks. Two major experiments were performed. Experiment 1: To determine if posterior eye cup tissues from myopic eye stimulates and hyperopic eye inhibits scleral cell proliferation, when co-cultured with scleral cells in vitro. This study comprised two linked experiments, i) monocular visual treatments of FDM (form-deprivation myopia), LIM (lens-induced myopia) and LIH (lens-induced hyperopia) with assessment of the effect of full punch eye cup tissue on DNA and GAG synthesis by cultured chick scleral fibroblasts, and ii) binocular visual treatments comprising LIM and LIH with assessment of the effect of individual layers of eye cup tissues (neural retina, RPE and choroid) on cultured chick scleral fibroblasts. Visual treatment was applied for 3 days. Experiment 2: To determine the direct interaction of GABA agents on scleral cell growth and to establish whether GABA agents modify the stimulatory/inhibitory effect of myopic and hyperopic posterior eye cup tissues on cultured scleral cell growth in vitro. Two linked experiments were performed. i) GABA agonists (muscimol and baclofen) and GABA antagonists (bicuculine (-), CGP46381 and TPMPA) were added to scleral cell culture medium to determine their direct effect on scleral cells. ii) GABAergic agents (agonists and antagonists) were administered to scleral fibroblasts co-cultured with posterior eye cup tissue (retina, RPE, retina/RPE, RPE/choroid). Ocular tissues were obtained from chick eyes wearing +15D (LIH) or -15D lenses (LIM) for 3 days. In both experiments, tissues were added to hanging cell culture insert (pore size 1.0ìm) placed over each well of 24 well plates while scleral cells were cultured in DMEM/F12, Glutamax (Gibco) plus 10% FBS and penicillin/streptomycin (50U/ml)) and fungizone (1.25ug/ml) (Gibco), at seeding density of 30,000 cells/well at the bottom of the well and allowed to grow for 3 days. Scleral cells proliferation rate throughout the study was evaluated by determining GAG and DNA content of scleral cells using Dimethylmethylene blue (DMMB) dye and Quant-iTTm Pico Green® dsDNA reagent respectively. Results and analysis: Based on DNA and GAG content, there was no significant difference in tissue effect of LIM and LIH eyes on scleral fibroblast growth (DNA: 8.4 ± 1.1μg versus 9.3 ± 2.3 μg, p=0.23; GAG: 10.13 ± 1.4 μg versus 12.67 ± 1.2 μg, F2,23=6.16, p=0.0005) when tissues were obtained from monocularly treated chick eyes (FDM or +15D lens or -15D lens over right eyes with left eyes untreated) and co-cultured as full punch. When chick eyes were treated binocularly with -15D lens (LIM) right eye and +15D lens (LIH) left eyes and tissue layers were separated, the retina from LIM eyes did not stimulate scleral cell proliferation compared to LIH eyes (DNA: 27.2 ± 6.7 μg versus 23.2 ± 1.5 μg, p=0.23; GAG: 28.1 ±3.7 μg versus 28.7 ± 4.2 μg, p=0.21). Similarly, the LIH and LIM choroid did not produce a differential effect based on DNA (LIM 46.9 ± 6.4 μg versus LIH 53.5 ± 4.7 μg, p=0.18), however the choroid from LIH eyes induced higher scleral GAG content than from LIM eyes (32.5 ± 6.7 μg versus 18.9 ± 1.2 μg, p=0.023). In contrast, the RPE from LIM eyes caused a significant increase in fibroblast proliferation whereas the RPE from LIH eyes was relatively inhibitory (72.4 ± 6.3 μg versus 27.9 ± 2.3 μg, F1, 6=69.99, p=0.0005). GAG data were opposite to DNA data e.g. the RPE from LIH eyes increased (33.7 ± 7.9 μg) while the RPE from LIM eyes decreased (28.2 ± 3.0 μg) scleral cell growth (F1, 6=13.99, p=0.010). Based on DNA content, GABA agents had a small direct effect on scleral cell growth; GABA agonists increased (21.4 ± 1.0% and 18.3 ± 1.0% with muscimol and baclofen, p=0.0021), whereas GABA antagonists decreased fibroblast proliferation (-23.7 ± 0.9% with bicuculine & CGP46381 and -28.1 ± 0.5% with TPMPA, p=0.0004). GABA agents also modified the effect of LIM and LIH tissues (p=0.0005).The increase in proliferation rate of scleral fibroblasts co-cultured with tissues (RPE, retina, RPE/retina and RPE/choroid) from LIM treated eyes was enhanced by GABA agonists (muscimol: 27.4 ± 1.2%, 35.8 ± 1.6%, 8.4 ± 0.3% and 11.9 ± 0.6%; baclofen: 27.0 ± 1.0%, 15.8 ± 1.5%, 16.8 ± 1.2% and 15.4 ± 0.4%, p=0.014) whereas GABA antagonists further reduced scleral fibroblasts growth (bicuculine: -52.5 ± 2.5%, -36.9 ± 1.4%, -37.5 ± 0.6% and -53.7 ± 0.9%; TPMPA: 57.3 ± 1.3%, -15.7 ± 1.2%, -33.5 ± 0.4% and -45.9 ± 1.5%; CGP46381: -51.9 ± 1.6%, -28.5 ± 1.5%, -25.4 ± 2.0% and -45.5 ± 1.9% respectively, p=0.0034). GAG data were opposite to DNA data throughout the experiment e.g. GABA agonists further inhibited while antagonists relatively enhanced scleral fibroblasts growth for both LIM and LIH tissue co-culture. The effect of GABA agents was relatively lower (p=0.0004) for tissue from LIH versus LIM eyes but was in a similar direction. There was a significant drug effect on all four tissue types e.g. RPE, retina, RPE/retina and RPE/choroid for both LIM and LIH tissue co-culture (F20,92=3.928, p=0.0005). However, the effect of GABA agents was greatest in co-culture with RPE tissue (F18,36=4.865, p=0.0005). Summary and Conclusion: 1) Retinal defocus signals are transferred to RPE and choroid which then exert their modifying effect on scleral GAG and DNA synthesis either through growth stimulating factors or directly interacting with scleral cells in process of scleral remodeling during LIM and LIH visual conditions. 2) GABAergic agents affect the proliferation of scleral fibroblasts both directly and when co-cultured with ocular tissues in vitro.

Drugs and local chemical mediators

10.1 Histamine and cytokines 10.1.1 Actions of histamine 10.1.2 Drugs that modify the actions of histamine 10.1.3 Cytokines 10.2 Eicosanoids 10.2.1 Cyclooxygenase (COX) and lipooxygenase system 10.2.2 Actions of eicosanoids 10.2.3 Drugs that modify the actions of eicosanoids 10.2.3.1 Inhibit phospholipase A2 10.2.3.2 Non-selective cyclooxygenase inhibitors 10.2.3.3 Selective COX-2 inhibitors 10.2.3.4 Agonists at prostaglandin receptors 10.2.3.5 Leukotriene receptor antagonists 10.3. 5-Hydroxtryptamine (serotonin), nitric oxide, and endothelin 10.3.1 5-HT and migraine 10.3.2 5-HT and the gastrointestinal tract 10.3.3 Nitric oxide and angina 10.3.4 Nitric oxide and erectile dysfunction 10.3.5 Endothelin and pulmonary hypertension

Drugs for hypertension, angina and heart failure

12.1 Drugs for hypertension 12.1.1 Epidemiology and pathophysiology 12.1.2 Diuretics for hypertension 12.2.3 Vasodilators for hypertension 12.4.4 β-Adrenoceptor blockers for hypertension 12.2. Drugs for angina 12.2.1 Typical angina 12.2.2 Drugs to treat an attack of typical angina 12,2.3 Drugs to prevent an attack of typical angina 12.2.4 Atypical angina 12.3 Drugs for heart failure 12.3.1 The heart failure epidemic 12.3.2 Compensatory changes in heart failure 12.3.3 Diuretics for heart failure 12.3.4 ACE inhibitors and AT1-receptor antagonists 12.3.5 β-adrenoceptor antagonists 12.3.6 Digoxin

Drugs for cardiac arrhythmmias, antithrombotic drugs and lipid modulating drugs

13.1 Drugs for cardiac arrhythmias 13.1.1 Introduction to cardiac arrhythmias 13.1.2 Cardiac action potentials 13.1.3 Mechanisms of cardiac arrhythmias 13.1.3 Class I 13.1.4 Class II 13.1.5 Class III 12.1.6 Class IV 13.1.7 Amiodarone 13.1.8 Adenosine 13.2 Antithrombotic drugs 13.2.1 Thrombus formation 13.2.2 Platelet aggregation and anti-platelet drugs 13.2.3 Coagulation 13.2.4 Anticoagulants 13.2.5 Fibrinolysis and fibrinolytics 13.3. Lipid modulating drugs 13.3.1 Cholesterol 13.3.2 Statins 13.3.3 Fibric acid derivatives 13.3.4 Ezetimibe

Drugs and the gastrointestinal tract

16.1. Agents to control acidity 16.1.1 Antacids 16.1.2 Proton pump inhibitors and antibiotics for Helicobacter pylori 16.1.3 Histamine H2 receptor antagonists 16.1.4 Misoprostol 16.1.5 Sucralfate 16.2. Prokinetics and emetics 16.2.1 Introduction to prokinetics 16.2.2 Prokinetic agents 16.2.3 Emesis with cytotoxic drugs and drugs for 16.2.4 Motion sickness and drugs for 16.2.5 Drugs for post-operative emesis 16.3. Agents used for diarrhea, constipation, irritable bowel syndrome 16.3.1 Treatment for diarrhea 16.3.2 Treatment for constipation 16.3.3 Treatment for opioid-induced constipation 16.4. Drugs for inflammatory bowel disease 16.4.1 Mesalazine 16.4.2 Glucocorticoids 16.4.3 Infliximab

Drugs and the respiratory system

17.1 Drugs for bronchial asthma and Chronic Obstructive Pulmonary Disease (COPD) 17.1.1 Introduction to asthma 17.1.2 Introduction to COPD 17.1.3 Drug delivery by inhalation 17.1.4 Drugs to treat 17.1.4.1 β2-adrenoceptor agonists 17.1.4.2 Muscarinic receptor antagonists 17.1.4.3 Leukotriene receptor antagonists 17.1.4.4 Theophylline 17.1.4.5 Oxygen for COPD 17.1.5 Drugs to prevent asthma 31.5.1 Glucocorticoids 31.5.2 Cromolyn sodium 17.1.6 Combination to treat and prevent asthma 17.1.7 Drug for allergic asthma – omalizumab 17.1.8 Emergency treatment of asthma 17.2. Expectorants, mucolytics, cough and oxygen 17.2.1 Introduction to expectorants and mucolytics 17.2.2 Expectorants 17.2.3 Mucolytics 17.2.4 Cough 17.2.5 Oxygen 17.3. Drugs for rhinitis and rhinorrea 17.3.1 Introduction 17.3.2 Histamine and H1-receptor antagonists 17.3.3 Sympathomimetic 17.3.4 Muscarinic receptor antagonists 17.3.4 Cromolyn sodium 17.3.5 Glucocorticoids

Anti-infectives

18.1 Antibiotics 18.1.1 Introduction to bacteria 18.1.2 Introduction to antibiotics 18.1.3 Inhibitors of bacterial cell wall synthesis 18.1.3.1 β-Lactams 18.1.3.2 Glycopeptides 18.1.4 Inhibitors of bacterial protein synthesis 18.1.4.1 Tetracyclines 18.1.4.2 Aminoglycosides 18.1.4.3 Chloramphenicol 18.1.4.4 Macrolides 18.1.4.5 Lincosamides 18.1.4.6 Oxalazidones 18.1.5 Inhibitors of DNA synthesis 18.2. Anti-tuberculotic drugs 18.2.1 Introduction 18.2.2 Isoniazid 18.2.3 Ethambutol 18.2.4 Rifamycin 18.2.5 Pyrazinamide 18.3. Anti-viral drugs 18.3.1 Introduction to viruses 18.3.2 Drugs used to treat herpesviruses 18.3.3 Drugs used to treat the flu 18.3.4 Drugs used to treat HIV/AIDS 18.4. Antifungal drugs 18.4.1 Introduction to Fungi 18.4.2 Antifungal drugs

Psychotropic drugs

19.1 Depression and Antidepressants 19.1.1 Depression 19.1.2 Neurochemistry of Depression and the Monoamine Theory 19.1.3 Antidepressant Indications and Drug Classes 19.1.4 General Considerations with the use of Antidepressants 19.1.5 Tricyclic Antidepressants 19.1.6 Monoamine Oxidase Inhibitors 19.1.7 Selective Serotonin Reuptake Inhibitors 19.1.8 Combined Serotonin and Noradrenaline Reuptake Inhibitors 19.1.9 Long Term Adaptive Changes with Antidepressants 19.2 Psychosis, Schizophrenia, and Antipsychotics 19.2.1 Psychosis and Schizophrenia 19.2.2 Neurochemistry of Psychosis and the Dopamine Theory 19.2.3 Antipsychotic Drug Indications and Drug Classes 19.2.4 Antipsychotic Mechanisms of Action 19.2.5 Typical Antipsychotics (First Generation) 19.2.6 Atypical Antipsychotics (Second Generation) 19.3 Anxiety and Anxiolytics 19.3.1 Fear, Anxiety and Anxiety Disorders 19.3.2 Neurochemistry of Anxiety 19.3.3 Anxiolytic Drug Indications and Drug Classes 19.3.4 Benzodiazepines 19.3.5 Antidepressants 19.3.6 Buspirone

Neurological drugs and opioids for pain management

20.1 Epilepsy and an introduction to drugs used to treat 20.1.1 Introduction to epilepsy 20.1.2 Treatment of partial seizures 20.1.3 Treatment of generalised seizures 20.1.4 Treatment of status epilepticus 20.2 Neurodegenerative disorders; principles of treatment 20.2.1 Introduction to neurodegenerative disorders 20.2.2 Parkinson’s disease 20.2.2.1 Introduction to Parkinson’s disease 20.2.2.2 Dopaminergic system 20.2.2.3 Treatment to enhance the dopaminergic system 20.2.2.4 Treatment to inhibit the cholinergic system 20.2.3 Dementia/Alzheimer’s disease 20.2.3.1 Introduction to Alzheimer’s disease 20.2.3.2 Treatment of Alzheimer’s disease 20.2.4 Amyotrophic lateral sclerosis 43.4.1 Introduction 43.4.2 Treatment 20.3. Pain and opioid analgesics 20.3.1 Introduction to pain and analgesia 20.3.2 Introduction to opioids 20.3.3 Tolerance and physical dependence 20.3.4 Effects of opioids 20.3.5 Agonists at opioid μ receptors 20.3.6 Toxicity to opioids This section deals with the neurologic drugs. The neurologic drugs are used to treat epilepsy and neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease. The opioids for pain management are also discussed in this section.

An introduction to anticancer drugs

An introduction to anticancer drugs 24.1 Introduction 24.2 The rationale behind anticancer drug therapy 24.3 Drugs used in cancer 24.3.1 Alkylating agents 24.3.2 Cytotoxic antibiotics 24.3.3 Antimetabolites 24.3.4 Microtubule inhibitors 24.3.5 Monoclonal antibodies 24.3.6 Steroid hormones and their antagonists 24.3.7 Other treatments

Drugs affecting blood

25. Drugs affecting blood 25.1 Introduction 25.2 Important dysfunctions of the blood system 25.3 Drugs used in to correct dysfunctions of the blood 25.3.1 Anti-thrombosis treatments 25.3.1.1 Platelet aggregation inhibitors 25.3.1.2 Anticoagulants 25.3.1.3 Thrombolytics 25.3.2 Treatments for anaemia 25.3.3 Treatments for bleeding disorders

Effects of acute multinutrient supplementation on rugby union game performance and recovery

Purpose: To investigate the effects of an acute multinutrient supplement on game-based running performance, peak power output, anaerobic by-products, hormonal profiles, markers of muscle damage, and perceived muscular soreness before, immediately after, and 24 h following competitive rugby union games. Methods: Twelve male rugby union players ingested either a comprehensive multinutrient supplement (SUPP), [RE-ACTIVATE:01], or a placebo (PL) for 5 d. Participants then performed a competitive rugby union game (with global positioning system tracking), with associated blood draws and vertical jump assessments pre, immediately post and 24 h following competition. Results: SUPP ingestion resulted in moderate to large effects for augmented 1st half very high intensity running (VHIR) mean speed (5.9 ± 0.4 vs 4.8 ± 2.3 m·min–1; d= 0.93). Further, moderate increases in 2nd half VHIR distance (137 ± 119 vs 83 ± 89 m; d= 0.73) and VHIR mean speed (5.9 ± 0.6 v 5.3 ± 1.7 m·min–1; d= 0.56) in SUPP condition were also apparent. Postgame aspartate aminotransferase (AST; 44.1 ± 11.8 vs 37.0 ± 3.2 UL; d= 1.16) and creatine kinase (CK; 882 ± 472 vs. 645 ± 123 UL; d= 0.97) measures demonstrated increased values in the SUPP condition, while AST and CK values correlated with 2nd half VHIR distance (r= –0.71 and r= –0.76 respectively). Elevated C-reactive protein (CRP) was observed postgame in both conditions; however, it was significantly blunted with SUPP (P= .05). Conclusions: These findings suggest SUPP may assist in the maintenance of VHIR during rugby union games, possibly via the buffering qualities of SUPP ingredients. However, correlations between increased work completed at very high intensities and muscular degradation in SUPP conditions, may mask any anticatabolic properties of the supplement.

Comparison of two methods to assess malnutrition in community-dwelling people with Parkinson's disease

Nutritional status in people with Parkinson’s disease (PD) has previously been assessed in a number of ways including BMI, % weight loss and the Mini-Nutritional Assessment(MNA). The symptoms of the disease and the side effects of medication used to manage them result in a number of nutrition impact symptoms that can negatively influence intake. These include chewing and swallowing difficulties, lack of appetite, nausea, and taste and smell changes, among others. Community-dwelling people with PD, aged >18 years, were recruited (n=97, 61 M, 36 F). The Patient-Generated Subjective Global Assessment(PG-SGA) and (MNA) were used to assess nutritional status. Weight, height, mid-arm circumference(MAC) and calf circumference were measured. Based on SGA, 16(16.5%) were moderately malnourished (SGA B) while none were severely malnourished (SGA C). The MNA identified 2(2.0%) as malnourished and 22(22.7%) as at risk of malnutrition. Mean MNA scores were different between the three groups,F(2,37)=7.30,p<.05 but not different between SGA B (21.0(2.9)) and MNA at risk (21.8(1.4)) participants. MAC and calf circumference were also different between the three groups,F(2,37)=5.51,p<.05 and F(2,37)=15.33,p<.05 but not between the SGA B (26.2(4.2), 33.3(2.8)) and MNA at risk (28.4(5.6), 36.4(4.7)) participants. The MNA results are similar to other PD studies using MNA where prevalence of malnutrition was between 0-2% with 20-33% at risk of malnutrition. In this population, the PG-SGA may be more sensitive to assessing malnutrition where nutrition impact symptoms influence intake. With society’s increasing body size, it might also be more appropriate as it does not rely on MAC and calf circumference measures.

Sensory imagery in craving : from cognitive psychology to new treatments for addiction

Sensory imagery is a powerful tool for inducing craving because it is a key component of the cognitive system that underpins human motivation. The role of sensory imagery in motivation is explained by Elaborated Intrusion (EI) theory. Imagery plays an important role in motivation because it conveys the emotional qualities of the desired event, mimicking anticipated pleasure or relief, and continual elaboration of the imagery ensures that the target stays in mind. We argue that craving is a conscious state, intervening between unconscious triggers and consumption, and summarise evidence that interfering with sensory imagery can weaken cravings. We argue that treatments for addiction can be enhanced by the application of EI theory to maintain motivation, and assist in the management of craving in high-risk situations.

Static vertical displacement measurement of bridges using Fiber Bragg Grating (FBG) sensors

Vertical displacements are one of the most relevant parameters for structural health monitoring of bridges in both the short and long terms. Bridge managers around the globe are always looking for a simple way to measure vertical displacements of bridges. However, it is difficult to carry out such measurements. On the other hand, in recent years, with the advancement of fiber-optic technologies, fiber Bragg grating (FBG) sensors are more commonly used in structural health monitoring due to their outstanding advantages including multiplexing capability, immunity of electromagnetic interference as well as high resolution and accuracy. For these reasons, using FBG sensors is proposed to develop a simple, inexpensive and practical method to measure vertical displacements of bridges. A curvature approach for vertical displacement measurements using curvature measurements is proposed. In addition, with the successful development of FBG tilt sensors, an inclination approach is also proposed using inclination measurements. A series of simulation tests of a full- scale bridge was conducted. It shows that both of the approaches can be implemented to determine vertical displacements for bridges with various support conditions, varying stiffness (EI) along the spans and without any prior known loading. These approaches can thus measure vertical displacements for most of slab-on-girder and box-girder bridges. Besides, the approaches are feasible to implement for bridges under various loading. Moreover, with the advantages of FBG sensors, they can be implemented to monitor bridge behavior remotely and in real time. A beam loading test was conducted to determine vertical displacements using FBG strain sensors and tilt sensors. The discrepancies as compared with dial gauges reading using the curvature and inclination approaches are 0.14mm (1.1%) and 0.41mm (3.2%), respectively. Further recommendations of these approaches for developments will also be discussed at the end of the paper.