Platelet-rich Plasma (PRP) in Orthopedics and Traumatology — Review

In the last few years various methods are being applied in the use of platelet-rich plasma (PRP) during treatment in different orthopedic disease and sports trauma. They allow improvement of local biological condition and regeneration of different types of tissues. PRP is a modern treatment strategy with worldwide recognition. There is a high concentration of platelet growth factors in small amounts of plasma. PRP and its various forms have become one of the best methods to support the healing process of various tissues. PRP is used in regenerative medicine, because it provides two of three components (growth factors and scaffolds) necessary for complete tissue regeneration. The particular reason for the appearance of lesions is important in order to select an appropriate treatment method and technical application. Main indications are acute and chronic wounds, pseudarthrosis, ligament and muscle injuries, some tendinopathies, osteoarthritis, chondral injuries

The Banking Sector and the Great Depression in Bulgaria, 1924 - 1938: Interlocking and Financial Sector Profitability

The economic narratives of Southeast Europe during the first part of the 20th century are currently being re-written. A story of failed industrialisation and delayed modernisation during the Interwar period has dominated since the pioneering work of Gerschenkron, but not enough aggregate data are available to see this as the only interpretation. In particular, virtually nothing is known about the financial system. This paper has two aims. First, it looks at the banking sector in Bulgaria in 1924- 1938. We provide new data for the 1920s rise and the 1930s decline of the Bulgarian banking sector and we evaluate its potential contribution to Bulgarian economic growth. In the second part, we discuss different explanations for the widespread collapse of commercial banks after the onset of the Great Depression. Relying on a new data set for over 100 Bulgarian commercial banks, we show that traditional explanations for the collapse of European commercial banks in the 1930s (based on the default of risky loans and falling asset prices due to deflation) need to be complemented by the pernicious effects of widespread insider lending in the Bulgarian case. We conclude that insider lending was the single most important factor behind the demise of the private banking system after the onset of the Depression.Bulgarian economic development; Banking and finance; Great Depression; Insider lending

Rastertunnelmikroskopische Untersuchungen zur Selbstorganisation und molekularen Erkennung von Tetralactam-Makrocyclen auf Oberflächen

In dieser Arbeit wurden die Selbstorganisation von Tetralactam-Makrocyclen (TLM) auf Einkristalloberflächen sowie die molekulare Erkennung ausgewählter organischer Moleküle (4-amino-N-(4-trityl-phenyl)-benzamide, s.g. "Stopper") in den selbstorganisierten TLM-Schichten mittels Rastertunnelmikroskopie (STM) untersucht. Diese Moleküle sind mögliche Bausteine für künstliche molekulare Maschinen und sind bekanntlich für die Synthese von Rotaxanen eingesetzt worden. Ziele waren die Aufklärung der zugrunde liegenden Mechanismen der Selbstorganisation der TLM-Moleküle auf Oberflächen sowie das Verständnis der Rolle der oberflächenbedingten Templat-Effekte für die Strukturbildung und für die molekulare Erkennung, und damit ein besseres Verständnis der Mechanismen bei der Synthese oberflächengebundener molekularer Maschinen. Zum Erreichen der gestellten Ziele wurden Monolagen aus Tetralactam-Makrocyclen auf der Au(111)-Oberfläche mittels STM im Ultrahochvakuum untersucht. Die STM-Bilder zeigten, dass die TLM-Moleküle zweidimensionale geordnete Strukturen (s.g. a- und ß-Struktur) für Submonolagen- und Monolagenbedeckungen bilden. Der Aufbau dieser Strukturen wurde mit Hilfe von Dichtefunktionaltheorie-Rechnungen (DFT) aufgeklärt. Die Selbstorganisation der Tetralactam-Makrocyclen in der a- und ß-Struktur auf der Au(111)-Oberfläche beruht auf der Bildung von Paaren von intermolekularen Wasserstoffbrücken zwischen benachbarten Makrocyclen. Zusammen mit einer passenden Konformation der Makrocyclen führt das zur Ausbildung von Dimeren, Trimeren und linearen Ketten (in der a-Struktur) aus den Makrocyclen, deren Anordnung auf der Oberfläche die geordneten a- und ß-Strukturen ergibt. Eine wichtige Eigenschaft der TLM-Moleküle, die zur Ausbildung der geordneten Strukturen beiträgt, ist die sterische Abschirmung ihrer reaktiven funktionellen Gruppen von der Au(111)-Oberfläche durch jeweils vier Methyl-Gruppen auf jeder Seite der Makrocyclusebene. Dadurch sind die näherungsweise flach liegenden Makrocyclen an der Oberfläche nur schwach durch Physisorption gebunden. Allen geordneten Strukturen ist gemeinsam, dass sie in der Kristallstruktur des TLM-Festkörpers nicht beobachtet werden. Daraus wurde auf die Rolle des Au(111)-Substrats für die zweidimensionale Strukturbildung geschlossen. Im Fall der am besten untersuchten a-Struktur kann man die Au(111)-Oberfläche als ein strukturloses, planares Templat betrachten, welches eine für die Strukturbildung wichtige planare Lage der Makrocyclen auf der Oberfläche bewirkt. Zum Zweck der Untersuchung der molekularen Erkennung der Stopper-Moleküle in den geordneten Schichten der Tetralactam-Makrocyclen wurden die Stopper-Moleküle durch Aufdampfen im Ultrahochvakuum auf die TLM-Schichten bei verschiedenen Substrattemperaturen aufgebracht und mittels STM untersucht. Die gefundenen gut definierten Adsorptionsplätze der Stopper-Moleküle in den Kavitäten der TLM-Moleküle bei niedrigen Temperaturen erwiesen sich als kinetisch stabilisiert, konnten jedoch nicht als thermodynamisch stabil bestimmt werden. Sie wurden außerdem bei Raumtemperatur nicht beobachtet. Stattdessen wurden die TLM-Schichten bei Raumtemperatur an ihren Inselrändern durch die Stopper-Moleküle teilweise zerstört. Diese Beobachtungen wurden durch einen nur schwachen Templat-Effekt bei der Adsorption der Stopper-Moleküle in die Kavitäten der Makrocyclen (s.g. Durchfädelung) in den geordneten TLM-Schichten erklärt. Die Ursache dafür ist die Makrocyclus-Konformation, welche die Orientierung der für den Templat-Effekt wichtigen NH-Gruppen in den TLM-Kavitäten bestimmt. Bei TLM-Molekülen in der geordneten Schicht ist diese Orientierung für eine starke und thermodynamisch stabile Adsorption der Stopper-Moleküle nicht geeignet. Eine weitere mögliche Ursache für den schwachen Templat-Effekt ist möglicherweise die Aktivierungsenergie für die Konformationsänderungen der Makrocyclen in der a-Struktur, weil die Bewegungsfreiheitsgrade eines TLM-Moleküls im Inneren der a-Struktur durch seine Wechselwirkungen mit den Nachbarmolekülen stark reduziert sind. Eine zusätzliche Rolle spielt vermutlich auch die Substrat-Oberfläche, die zu einer sterischen Hinderung bei der Durchfädelung der Stopper-Moleküle in die Kavitäten der Makrocyclen führen kann

Effects of low-frequency whole-body vibration on motor-evoked potentials in healthy men.

addresses: Sport and Exercise Science Research Centre, Faculty of Engineering, Science and The Built Environment, London South Bank University, 103 Borough Road, London SE1 0AA, UK. [email protected] is the author's post-print version of an article published in Experimental Physiology, 2009, Vol. 94, Issue 1, pp. 103 - 116 Copyright © 2009 Wiley-Blackwell /The Physiological Society. The definitive version is available at www3.interscience.wiley.comThe aim of this study was to determine whether low-frequency whole-body vibration (WBV) modulates the excitability of the corticospinal and intracortical pathways related to tibialis anterior (TA) muscle activity, thus contributing to the observed changes in neuromuscular function during and after WBV exercise. Motor-evoked potentials (MEPs) elicited in response to transcranial magnetic stimulation (TMS) of the leg area of the motor cortex were recorded in TA and soleus (SOL) muscles of seven healthy male subjects whilst performing 330 s continuous static squat exercise. Each subject completed two conditions: control (no WBV) and WBV (30 Hz, 1.5 mm vibration applied from 111 to 220 s). Five single suprathreshold and five paired TMS were delivered during each squat period lasting 110 s (pre-, during and post-WBV). Two interstimulus intervals (ISIs) between the conditioning and the testing stimuli were employed in order to study the effects of WBV on short-interval intracortical inhibition (SICI, ISI = 3 ms) and intracortical facilitation (ICF, ISI = 13 ms). During vibration relative to squat exercise alone, single-pulse TMS provoked significantly higher TA MEP amplitude (56 +/- 14%, P = 0.003) and total area (71 +/- 19%, P = 0.04), and paired TMS with ISI = 13 ms provoked smaller MEP amplitude (-21 +/- 4%, P = 0.01) but not in SOL. Paired-pulse TMS with ISI = 3 ms elicited significantly lower MEP amplitude (TA, -19 +/- 4%, P = 0.009; and SOL, -13 +/- 4%, P = 0.03) and total area (SOL, -17 +/- 6%, P = 0.02) during vibration relative to squat exercise alone in both muscles. Tibialis anterior MEP facilitation in response to single-pulse TMS suggests that WBV increased corticospinal pathway excitability. Increased TA and SOL SICI and decreased TA ICF in response to paired-pulse TMS during WBV indicate vibration-induced alteration of the intracortical processes as well

GBA-associated Parkinson’s disease in Hungary: clinical features and genetic insights

Introduction: Parkinson’s disease (PD) has a complex genetic background involving both rare and common genetic variants. Although a small percentage of cases show a clear Mendelian inheritance pattern, it is much more relevant to identify patients who present with a complex genetic profile of risk variants with different severity. The ß-glucocerebrosidase coding gene (GBA1) is recognized as the most frequent genetic risk factor for PD and Lewy body dementia, irrespective of reduction of the enzyme activity due to genetic variants. Methods: In a selected cohort of 190 Hungarian patients with clinical signs of PD and suspected genetic risk, we performed the genetic testing of the GBA1 gene. As other genetic hits can modify clinical features, we also screened for additional rare variants in other neurodegenerative genes and assessed the APOE-ε genotype of the patients. Results: In our cohort, we identified 29 GBA1 rare variant (RV) carriers. Out of the six different detected RVs, the highly debated E365K and T408M variants are composed of the majority of them (22 out of 32). Three patients carried two GBA1 variants, and an additional three patients carried rare variants in other neurodegenerative genes (SMPD1, SPG11, and SNCA). We did not observe differences in age at onset or other clinical features of the patients carrying two GBA1 variants or patients carrying heterozygous APOE-ε4 allele. Conclusion: We need further studies to better understand the drivers of clinical differences in these patients, as this could have important therapeutic implications. © 2023, The Author(s)

Preconditioning tDCS facilitates subsequent tDCS effect on skill acquisition in older adults.

Functional motor declines that often occur with advancing age-including reduced efficacy to learn new skills-can have a substantial impact on the quality of life. Recent studies using noninvasive brain stimulation indicate that priming the corticospinal system by lowering the threshold for the induction of long-term potentiation-like plasticity before skill training may facilitate subsequent skill learning. Here, we used "priming" protocol, in which we used transcranial direct current stimulation (tDCS) applying the cathode over the primary motor cortex (M1) before the anode placed over M1 during unimanual isometric force control training (FORCEtraining). Older individuals who received tDCS with the cathode placed over M1 before tDCS with the anode placed over M1 concurrent with FORCEtraining showed greater skill improvement and corticospinal excitability increases following the tDCS/FORCEtraining protocol compared with both young and older individuals who did not receive the preceding tDCS with the cathode placed over M1. The results suggested that priming tDCS protocols may be used in clinical settings to improve motor function and thus maintain the functional independence of older adults

Balancing with Vibration: A Prelude for “Drift and Act” Balance Control

Stick balancing at the fingertip is a powerful paradigm for the study of the control of human balance. Here we show that the mean stick balancing time is increased by about two-fold when a subject stands on a vibrating platform that produces vertical vibrations at the fingertip (0.001 m, 15–50 Hz). High speed motion capture measurements in three dimensions demonstrate that vibration does not shorten the neural latency for stick balancing or change the distribution of the changes in speed made by the fingertip during stick balancing, but does decrease the amplitude of the fluctuations in the relative positions of the fingertip and the tip of the stick in the horizontal plane, A(x,y). The findings are interpreted in terms of a time-delayed “drift and act” control mechanism in which controlling movements are made only when controlled variables exceed a threshold, i.e. the stick survival time measures the time to cross a threshold. The amplitude of the oscillations produced by this mechanism can be decreased by parametric excitation. It is shown that a plot of the logarithm of the vibration-induced increase in stick balancing skill, a measure of the mean first passage time, versus the standard deviation of the A(x,y) fluctuations, a measure of the distance to the threshold, is linear as expected for the times to cross a threshold in a stochastic dynamical system. These observations suggest that the balanced state represents a complex time–dependent state which is situated in a basin of attraction that is of the same order of size. The fact that vibration amplitude can benefit balance control raises the possibility of minimizing risk of falling through appropriate changes in the design of footwear and roughness of the walking surfaces

Evolving concepts on the age-related changes in “muscle quality”

The deterioration of skeletal muscle with advancing age has long been anecdotally recognized and has been of scientific interest for more than 150 years. Over the past several decades, the scientific and medical communities have recognized that skeletal muscle dysfunction (e.g., muscle weakness, poor muscle coordination, etc.) is a debilitating and life-threatening condition in the elderly. For example, the age-associated loss of muscle strength is highly associated with both mortality and physical disability. It is well-accepted that voluntary muscle force production is not solely dependent upon muscle size, but rather results from a combination of neurologic and skeletal muscle factors, and that biologic properties of both of these systems are altered with aging. Accordingly, numerous scientists and clinicians have used the term “muscle quality” to describe the relationship between voluntary muscle strength and muscle size. In this review article, we discuss the age-associated changes in the neuromuscular system—starting at the level of the brain and proceeding down to the subcellular level of individual muscle fibers—that are potentially influential in the etiology of dynapenia (age-related loss of muscle strength and power)