Efficacy, Safety, and Tolerability of Psychedelics in Treatment-Resistant Depression (TRD)

Major depressive disorder (MDD) is a highly prevalent psychiatric disorder, associated with substantial burden and large economical costs. Notwithstanding various conventional antidepressant treatment options, a large portion of depressed people (ca. 30%) fails to respond to first-line treatment, resulting in treatment-resistant depression (TRD). Although non-response to multiple antidepressant interventions is a common outcome, a consensus definition of TRD is not yet available. In practice, TRD is applied when two or more successive treatments with different antidepressants are not working. The last decade's intense research into new medicines for TRD has led to two developments, using typical or serotonergic (psilocybin, ayahuasca) and atypical (glutamatergic) psychedelics (ketamine, esketamine). Both approaches, although via different entrance mechanism, exhibit a fast onset but also long-lasting antidepressant effect far beyond the biological presence of the drug in the body, strongly indicating that downstream mechanisms activated by signaling cascades in the brain are involved. The present chapter describes the clinical development of psilocybin and esketamine for TRD and discusses the problems involved in the use of a proper placebo because of the psychotomimetic (psilocybin) or dissociative (ketamine) effects that interfere with performing "blind" studies. Nevertheless, intranasal esketamine was developed and approved for TRD, whereas psilocybin has shown positive results. Adverse effects and tolerability of both drugs in the dose ranges used are generally acceptable. The emergence of anti-TRD medicines for treatment of a very severe disease is a breakthrough in psychiatry.

A new approach to 'on-demand' treatment of lifelong premature ejaculation by treatment with a combination of a 5-HT1A receptor antagonist and SSRI in rats

Lifelong premature ejaculation (PE) in men lacks an adequate on-demand pharmacological treatment. Although selective serotonin reuptake inhibitors (SSRIs) are used for PE they only work after chronic treatment, or if used on-demand, less adequately than chronic SSRI treatment. It has been shown that the addition of a behaviorally silent 5-HT1A-receptor antagonist to an SSRI can generate acute inhibitory effects on male rat sexual behavior. Atlas987 is a selective 5-HT1A-receptor antagonist with equal potency to displace agonist and antagonist binding to pre- and post-synaptic 5-HT1A receptors in rat and human brain. To investigate whether Atlas987 together with the SSRI paroxetine, a combination called Enduro, induces acute inhibitory effects on male rat sexual behavior, we tested Enduro in Wistar rats in a dose-dependent manner. We first tested the 5-HT1A receptor antagonist Atlas987 in 8-OH-DPAT induced serotonergic behavior in rats. Second, we tested Enduro in a dose-dependent manner in male sexual behavior. Third, we tested the effective time window of Enduro's action, and lastly, we measured the plasma levels of Atlas987 and paroxetine over an 8-h period. Results showed that Enduro acutely and dose-dependently reduced the number of ejaculations and increased the ejaculation latencies. The behavioral pattern induced reflected a specific effect on sexual behavior excluding non-specific effects like sedation or sensoric-motoric disturbances. The time-window of activity of Enduro showed that this sexual inhibitory activity was at least found in a 1-4 h' time window after administration. Plasma levels showed that in this time frame both Atlas987 and paroxetine are present. In conclusion, in rats, Enduro is successful in acutely inhibiting sexual behavior. These results may be therapeutically attractive as "on demand" treatment for life-long premature ejaculation in men.

Kinematic differences between left- and right-handed cricket fast bowlers during the bowling action

Background

Despite differences between left- and right-handed athletes in other sports, minimal evidence exists regarding biomechanical similarities and differences between left- and right-handed cricket fast bowlers performing an equivalent task.

Objectives

This study aimed to compare the kinematics between left and right-handed fast bowlers performing an equivalent task (i.e. bowling 'over the wicket' to a batter of the same handedness as the bowler).

Methods

Full body, three-dimensional kinematic data for six left-handed and 20 right-handed adolescent, male, fast bowlers were collected using the Xsens inertial measurement system. Time-normalised joint and segment angle time histories from back foot contact to follow-through ground contacts were compared between groups via statistical parametric mapping. Whole movement and subphase durations were also compared.

Results

Left-handed players displayed significantly more trunk flexion from 49%-56% of the total movement (ball release occurred at 54%; p = 0.037) and had shorter back foot contact durations on average (0.153 vs 0.177 s; p = 0.036) compared to right-handed players.

Conclusion

Left- and right-handed bowlers displayed similar sagittal plane kinematics but appeared to use non-sagittal plane movements differently around the time of ball release. The kinematic differences identified in this study can inform future research investigating the effect of hand dominance on bowling performance and injury risk.

The core of performance in adolescent cricket pace bowlers: Trunk muscle stability, maybe, but not strength-endurance and thickness

Background

The trunk connects the upper and lower limbs and transfers energy during movement. Exploring the role of the trunk muscles in bowling performance affords us the opportunity to uncover potential mechanisms to improve bowling performance.

Objectives

To investigate the association between bowling performance and trunk muscle stability, strength-endurance and thickness in adolescent pace bowlers.

Methods

Adolescent pace bowlers participated in this cross-sectional study. Trunk muscle stability was measured using Sahrmann's Stability Scale, strength-endurance using the Bourbon Trunk Muscle Strength Test and thickness of the abdominal wall and lumbar multifidus muscles using ultrasound imaging.

Results

Forty-six pace bowlers with a mean age of 15.9 ±1.2 years participated. The average ball release speed was 109.2±11.8 km.h^-1. This measurement was higher in level four of stability than in level two (mean difference 22.2 ± SD 6.8 km.h^-1; p= .018). No link between ball release speed and strength-endurance could be found. Multiple correlations of moderate strength (r > 0.4) exist between ball release speed and absolute trunk muscle thickness with height and weight as confounding factors. The relationship between accuracy and the trunk muscle variables investigated in this study is weak.

Conclusion

Bowlers with better trunk muscle stability bowled faster than those with a lower level of trunk stability, irrespective of their age, height and weight. Trunk muscle thickness correlated with ball release speed; however, confounding factors such as height and weight play a role and therefore, findings need to be interpreted with caution.

The cycle ergometer test is not a reliable alternative to the countermovement jump in the assessment of power output

Background

Rugby union is a physically demanding collision sport that requires optimal neuromuscular function for maximal power output, with mechanical power an integral component of performance. Peak power (P_p) and relative P_p are parameters of neuromuscular function commonly assessed through the countermovement jump (CMJ) as a measure of fatigue. The Wattbike cycle ergometer test (CET) is a non-load bearing method of evaluating lower limb power. The cost-effective CET could therefore offer a viable alternative to the CMJ.

Objectives

This study aimed to determine the concurrent validity of the CMJ and CET.

Methods

Thirty-eight professional rugby union players performed twelve CMJs on a force platform with four loads (bodyweight: BW-CMJ; 20kg: 20-CMJ; 40kg: 40-CMJ and 60kg: 60-CMJ) and a six second peak power (6PPO) CET assessment on a Wattbike ergometer.

Results

CMJ power outputs were [BW-CMJ: P_p - 3101±648 W; 20-CMJ: P_p - 2724±513 W; 40-CMJ: P_p - 2490±496 W; 60-CMJ: P_p - 2238±366 W] and CET [P_p - 1310±161 W]. None of the CMJ-P_p values showed relationships with any CET power variables. Large (r = 0.51-0.63; p = 0.000 - 0.001) relationships were found to be between relative CMJ and relative CET power outputs. Bland-Altman plots, which were used to determine the level of agreement between the two assessments, showed the agreement between the tests was poor.

Conclusion

Though positive relationships existed between relative CMJ and relative CET power variables, analyses of the level of agreement in the Bland-Altman plots suggest that the two power assessment methods are not interchangeable measures of power.

A prevalence of running-related injuries among professional endurance runners in the Rift Valley, Kenya

Background

Injuries related to endurance running have attracted attention as the sport has become more competitive, and as athletes seek to improve their performance. Consequently, endurance runners are increasingly becoming more susceptible to lower extremity running injuries.

Objectives

The aim of this study was to establish the prevalence of running-related injuries among professional endurance runners in the Rift Valley, Kenya.

Methods

We used a cross-sectional survey design targeting professional endurance runners who had participated in both local and international running competitions. The sample size consisted of 209 respondents selected through stratified and simple random sampling techniques, of which 167 participated in the study. A self-administered questionnaire was used to collect data on the prevalence of injuries among the endurance runners. The data were analysed using descriptive statistics.

Results

The prevalence of running injuries was 63% (n=106). The prevalence among males (n=64; 69%) was higher in comparison with that of females (n=42; 57%). The posterior thigh was the most common site for injuries among the athletes (n=87; 52%), followed by the lower back (n=78; 47%) and ankle (n=63; 38%).

Conclusion

The prevalence of running-related injuries was high among professional Kenyan endurance runners compared to other populations. These findings therefore form the basis of future research to explore the mechanisms behind the injuries and the feasibility of targeted injury prevention programmes.

The epidemiology of injury and illness amongst athletes at the Indian Ocean Island Games, Mauritius, 2019

Background

The Indian Ocean Island Games is a multi-sport event that occurs every four years and includes athletes from seven islands of the Indian Ocean, namely, Comoros, Reunion, Mayotte, Madagascar, Maldives, Seychelles, and Mauritius.

Objectives

This study aims to describe the injury and illness epidemiology of the athletes participating during the 2019 Indian Ocean Islands Games.

Methods

This prospective cohort study recorded injury and illness cases from athletes who competed in these Games. All medical physicians received detailed instructions and training on data collection using an injury report form. All athletes (minors and adults) who provided consent, or consent given from the minors' guardians, were included in this study. Athletes who did not provide consent for this study were excluded.

Results

Athletes (n = 1 521; 531 women and 990 men) reported 160 injuries (injury incidence rate of 11%) and 85 illnesses (illness incidence rate of 6%). The percentage of distribution of injuries were highest in football and basketball. Most injuries occurred during competition, compared with training, joint sprains were the most common type of injury (28%), followed by muscle strains (19%). Men suffered most of the injuries (79% vs. 21% for women). Similarly, men sustained more illnesses than women (57% vs. 43%). Most illnesses affected the respiratory system (67%), and infection was the most common cause of illness (84%) in participating athletes.

Conclusion

These findings are similar to previous events in other parts of the world. However, unique ailments, not previously reported on, were discovered. Epidemiological data from this study can be inferred to athletes who compete in similar multi-sport events in the Indian Ocean region.

Injury prevention knowledge, beliefs, and practices among women's football teams in South Africa

Background

Numerous factors account for injury prevention or lack thereof in any team setting. With the increasing burden of injuries in women's football, and limited human resources accessible in sub-Saharan Africa, it is important to investigate the ways in which standardised injury prevention practices can be achieved.

Objectives

The study aimed to evaluate injury prevention knowledge, beliefs, and practices in women's football teams in the University Sport South Africa (USSA) Football League in Gauteng Province, South Africa.

Methods

A cross-sectional self-administered survey was conducted among women's football teams registered to participate in the USSA Football League in South Africa's Gauteng Province.

Results

A total of 107 respondents participated in the study, which included both players (n=98; 92%) and their support staff (n=9; 9%). The median (interquartile range) age of the participants was 22 (20-25) years. In the population sampled, 36% of the participants perceived that they had adequate knowledge of injury prevention practices in football, while others felt they had limited knowledge of the basic injury prevention programmes (IPPs). The results also indicated that the injury prevention practices of coaches (93%) and their beliefs in this regard (70%) are sufficient for achieving the basic injury prevention goals. Most of the respondents (89%) indicated that a medical support system is important in attaining the goals of injury prevention.

Conclusion

Members of women's teams in the USSA Football League have recognised limited knowledge about the basic IPPs, while they do employ some of the basic injury prevention practices in football. These practices could be influenced by the beliefs of the coaches and the players, and most of them believe that IPPs are important. It is essential as key stakeholders that coaches' and players' education and knowledge of injury prevention strategies should be considered as an integral part of the process to succeed. It should be strongly highlighted and implemented, thus augmenting the credibility, trust and compliance for IPPs in the sport.

Pharmacological Studies on the Role of 5-HT1 A Receptors in Male Sexual Behavior of Wildtype and Serotonin Transporter Knockout Rats

Brain serotonin (5-HT) neurotransmission plays an important role in male sexual behavior and it is well established that activating 5-HT_{1 A} receptors in rats facilitate ejaculatory behavior. However, the relative contribution of 5-HT_{1 A} somatodendritic autoreceptors and heteroreceptors in this pro-sexual behavior is unclear. Moreover, it is unclear whether the contribution of somatodendritic 5-HT_{1 A} autoreceptors and postsynaptic 5-HT_{1 A} heteroreceptors alter when extracellular 5-HT levels are chronically increased. Serotonin transporter knockout (SERT^-/-) rats exhibit enhanced extracellular 5-HT levels and desensitized 5-HT_{1 A} receptors. These rats model neurochemical changes underlying chronic SSRI-induced sexual dysfunction. We want to determine the role of presynaptic versus postsynaptic 5-HT_{1 A} receptors in the pro-sexual effects of 5-HT_{1 A} receptor agonists in SERT^+/+ and in SERT^-/- rats. Therefore, acute effects of the biased 5-HT_{1 A} receptor agonists F-13714, a preferential 5-HT_{1 A} autoreceptor agonist, or F-15599, a preferential 5-HT_{1 A} heteroreceptor agonist, and S15535 a mixed 5-HT_{1 A} autoreceptor agonist/heteroreceptor antagonist, on male sexual behavior were assessed. A clear and stable genotype effect was found after training where SERT^+/+ performed sexual behavior at a higher level than SERT^-/- rats. Both F-15599 and F-13714 induced pro-sexual activity in SERT^+/+ and SERT^-/- animals. Compared to SERT^+/+, the F13714-dose-response curve in SERT^-/- rats was shifted to the right. SERT^+/+ and SERT^-/- rats responded similar to F15599. Within both SERT^+/+ and SERT^-/- rats the potency of F-13714 was much stronger compared to F-15599. S15535 had no effect on sexual behavior in either genotype. In SERT^+/+ and SERT^-/- rats that were selected on comparable low sexual activity (SERT^+/+ 3 or less ejaculations and SERT^-/- 5 or less ejaculations in 10 weeks) S15535 also did not influence sexual behavior. The two biased compounds with differential effects on 5-HT_{1 A} auto- and hetero-receptors, exerted pro-sexual activity in both SERT^+/+ and SERT^-/- rats. Applying these specific pharmacological tools has not solved whether pre- or post-synaptic 5-HT_{1 A} receptors are involved in pro-sexual activity. Moreover, the inactivity of S15535 in male sexual behavior in either genotype was unexpected. The question is whether the in vivo pharmacological profile of the different 5-HT_{1 A} receptor ligands used, is sufficient to differentiate pre- and/or post-synaptic 5-HT_{1 A} receptor contributions in male rat sexual behavior.

Genotype scores predict drug efficacy in subtypes of female sexual interest/arousal disorder: A double-blind, randomized, placebo-controlled cross-over trial

Attempts to develop a drug treatment for female sexual interest/arousal disorder have so far been guided by the principle of ‘one size fits all’, and have failed to acknowledge the complexity of female sexuality. Guided by personalized medicine, we designed two on-demand drugs targeting two distinct hypothesized causal mechanisms for this sexual disorder. The objective of this study was to design and test a novel procedure, based on genotyping, that predicts which of the two on-demand drugs will yield a positive treatment response. In a double-blind, randomized, placebo-controlled cross-over experiment, 139 women with female sexual interest/arousal disorder received three different on-demand drug-combination treatments during three 2-week periods: testosterone 0.5 mg + sildenafil 50 mg, testosterone 0.5 mg + buspirone 10 mg, and matching placebo. The primary endpoint was change in satisfactory sexual events. Subjects’ genetic profile was assessed using a microarray chip that measures 300,000 single-nucleotide polymorphisms. A preselection of single-nucleotide polymorphisms associated with genes that are shown to be involved in sexual behaviour were combined into a Phenotype Prediction Score. The Phenotype Prediction Score demarcation formula was developed and subsequently validated on separate data sets. Prediction of drug-responders with the Phenotype Prediction Score demarcation formula gave large effect sizes (d = 0.66 through 1.06) in the true drug-responders, and medium effect sizes (d = 0.51 and d = 0.47) in all patients (including identified double, and non-responders). Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the Phenotype Prediction Score demarcation formula were all between 0.78 and 0.79, and thus sufficient. The resulting Phenotype Prediction Score was validated and shown to effectively and reliably predict which women would benefit from which on-demand drug, and could therefore also be useful in clinical practice, as a companion diagnostic establishing the way to a true personalized medicine approach.

Tramadol's Inhibitory Effects on Sexual Behavior: Pharmacological Studies in Serotonin Transporter Knockout Rats

Tramadol is an effective pharmacological intervention in human premature ejaculation (PE). To investigate whether the inhibitory action of tramadol is primarily caused by its selective serotonin reuptake inhibitory (SSRI) effects we tested the dose–response effects of tramadol on sexual behavior in serotonin transporter wild type (SERT^+/+), heterozygous (SERT^+/-), and knockout (SERT^-/-) rats. To investigate whether other mechanisms contribute to the inhibitory effects, WAY100,635, a 5-HT_1A receptor antagonist and naloxone, a μ-opioid receptor antagonist, were tested on sexual behavior together with tramadol. Tramadol dose-dependently decreases sexual activity in all genotypes. In all studies, SERT^+/- rats did not respond differently from SERT^+/+ rats. WAY100,635 did not affect sexual activity in SERT^+/+, but dose-dependently reduced sexual activity in SERT^-/- rats. WAY100,635 (0.3 mg/kg) combined with tramadol (20 mg/kg) significantly reduced sexual activity in SERT^+/+ and even stronger in SERT^-/- rats. Naloxone did not affect sexual behavior consistently in SERT^+/+ rats, while in SERT^-/- rats all doses reduced ejaculation frequency mildly. Combining naloxone (20 mg/kg) and tramadol (20 mg/kg) decreased ejaculation frequencies in both genotypes. Interestingly, combining tramadol (20 mg/kg), WAY100,635 (0.3 mg/kg) and naloxone (20 mg/kg) led to complete elimination of all sexual activity in both SERT^+/+ and SERT^-/- rats. These findings suggest that the inhibitory effects of tramadol on male sexual behavior in SERT^+/+ rats is mainly, if not exclusively, due to SERT inhibition, with an important role for 5-HT_1A receptors, although influence of other systems (e.g., noradrenergic) cannot be excluded. As SSRIs exert their sexual inhibition after chronic administration, tramadol may be therapeutically attractive as “on demand” therapy for PE.

A simulated rugby match protocol induces physiological fatigue without decreased individual scrummaging performance

Background: A rugby union game consists of 80 minutes of strenuous exertion. Forwards are required to participate in the arduous activity of scrummaging throughout a game.Objectives: The purpose of this study was to identify whether rugby-match simulated fatigue modified individual scrummaging technique and reduced performance.Methods: Twelve forwards (body mass 106.2±13.3 kg; stature 179.5±8.4 cm) had individual scrum kinetics and kinematics assessed prior to and following a protocol that simulated a rugby match. The simulated rugby match protocol required participants to run at various velocities and perform rugby specific tasks. Rating of Perceived Exertion (RPE) was assessed using a 6-20 Borg scale and Visual Analogue Scale (VAS). Blood lactate, heart rate and RPE were measured prior to, at mid-point and after the simulated game, while markers of muscle damage (blood creatine kinase activity (CK) and urea) were measured prior to and following the protocol.Results: RPE (p<0.0001) and VAS (p<0.0001) showed significant increases between the pre- and post-simulation values. Of the physiological markers, heart rate (p<0.0001) and blood urea concentration (p=0.004) increased following the match simulation. No significant differences were observed for blood CK (p=0.281), individual scrummaging forces (p=0.433) or in the kinematic variables following the protocol. While physiological fatigue and subjective ratings of physiological fatigue may develop during a rugby simulation, no differences were observed in peak forces or in body kinematics at peak force.Conclusion: Physiological fatigue does not influence individual scrummaging performance and technique.

A Large-Scale Automated Method for Hepatocyte Isolation: Effects on Proliferation in Culture

Large-scale sterile methods for isolating hepatocytes are desirable for the development of bioartificial liver support systems. In this study the traditional centrifuge method was compared with the use of a Baylor Rapid Autologous Transfusion (BRAT) machine for isolating large quantities of porcine hepatocytes. After isolating hepatocytes, the methods were evaluated in terms of cell viability and yield per liver, proliferation over 7 days, and the effects on the cell cycle using the trypan blue exclusion test, conventional phase-contrast light microscopy, the lactate to pyruvate ratio, the leakage of lactate dehydrogenase (LD) and aspartate aminotransferase (AST), lidocaine clearance, albumin production, and flow cytometry. With the centrifuge method the mean cell viability was 92.5%, while with the BRAT method the viability was 95.9%. The minimal cell yields with the BRAT procedure were 7.3 × 109 for 250-ml centrifuge bowls and 2.8 × 109 for 165-ml bowls, which compares well with that found by other authors. Because the same initial procedures were employed in both methods the total hepatocyte yield per liver was comparable. Flow cytometry confirmed that the proliferation of hepatocytes was facilitated by oxygenation during the isolation procedure. The recovery of hepatocytes in culture following isolation was similar after either method. Daily microscopic investigation indicated that cytoplasmic vacuolization and granularities were present after either procedure and these disappeared following 3–4 days of culturing. Flow cytometry indicated that the hepatocyte cell cycle was similar after either method; at 7 days the profile indicated that the cells were still proliferating. Trends in the lactate to pyruvate ratio and the leakage of LD and AST indicated that the functional polarity of hepatocytes was regained after approximately 3 days. Lidocaine clearance at 4 days indicated that the cytochrome P450 system was active, while significant albumin production was apparent at day 5. The benefit of using BRAT technology in hepatocyte isolation lies in guaranteed sterility, convenience, speed, and the ability to oxygenate media and cell suspensions during the procedure.