PROPRIETÀ ELETTRICHE DI MEMBRANA DI CELLULE MUSCOLARI SCHELETRICHE MURINE ED UMANE DIFFERENZIATE IN VITRO

2004/2005In questo lavoro sono state studiate le proprietà elettriche di membrana di cellule muscolari scheletriche murine ed umane durante la miogenesi in vitro. In particolare, si è studiato il ruolo delle conduttanze Ca2+ e K+ Ca2+- dipendenti nel generare l'attività elettrica pacemaker osservata in concomitanza con la contrazione meccanica in cellule murine in coltura dopo 4-5 giorni in medium di differenziamento. I risultati hanno rivelato che correnti Ca2+ voltaggio-dipendenti di tipo T sono responsabili della depolarizzazione del potenziale di membrana che facilita il raggiungimento della soglia per la nascita di potenziali d'azione TTX sensibili. Correnti K+ Ca2+ dipendenti di tipo SK, apaminosensibili sono attivate grazie all'ingresso di Ca2+ promosso dal potenziale d'azione e mediano l' iperpolarizzazione post-spike che, a sua volta, rimuove l'inattivazione dei canali Ca2+ di tipo T. Il gioco tra queste due conduttanze ioniche Na+ e K+ è quindi responsabile dell'attività elettrica spontanea osservata nei miotubi murini. In cellule muscolari scheletriche umane, isolate da cellule satelliti, in cui non si osserva attività spontanea in mancanza del nervo, abbiamo studiato il ruolo del fattore neurotrofico di origine neuronale, agrina nella modulazione delle proprietà passive e attive di membrana. In particolare abbiamo evidenziato che l' agrina riduce la resistenza di membrana, aumenta il potenziale di membrana a riposo in direzione iperpolarizzante, favorisce l'espressione della pompa Na+-K+, regola negativamente l'espressione di correnti K+ di tipo SK, facilita l'attivazione di correnti Ca2+ di tipo L e riduce l'espressione di correnti Ca2+ di tipo T. Tali fenomeni sono tutti stati osservati essere coinvolti nel processo di maturazione delle cellule muscolari. A conferma di ciò abbiamo rilevato che l'agrina facilita l'espressione delle componenti lente e veloci della catena pesante della miosina, una delle proteine contrattili maggiormente coinvolte nel processo di contrazione muscolare. L' agrina neuronale induce quindi il differenziamento della cellula muscolare durante la sinaptogenesi mimando l'attività promossa in vivo a livello di giunzione neuromuscolare ali' arrivo del terminale nervoso.XVIII Ciclo1974Versione digitalizzata della tesi di dottorato cartacea

Regular Physical Activity Influences Gut Microbiota with Positive Health Effects

The gut microbiota is believed to have a major impact on human health and disease. It is involved in barrier functions and maintenance of homeostasis. It provides nutrients and metabolites, participates in a signaling network, regulates epithelial development, and influences the immune system as well as protects the intestinal mucosa from the aggression of pathogenic microorganisms. There is growing evidence that physical activity has an impact on the gut microbiota. Recent studies in animals and humans suggest that regular physical activity increases the presence of beneficial microbial species and improves host health. However, some specific differences should be noted: different forms of physical activity, frequency or intensity, aerobic or resistance training, and benefits and consequences for amateur or competitive athletes. Because the positive role of physical activity can have an impact on health and various types of diseases, the results of research studies in this area are increasingly becoming the focus of scientific interest. In addition, probiotic supplements modulate intestinal microbial flora, and the ability of probiotics to modulate perturbations in immune function after exercise highlights their potential for use in individuals exposed to high levels of physical activity

Serumski bilirubin korelira s adipokinima u serumu kod asimptomatskih odraslih osoba s normalnom i prekomjernom tjelesnom težinom

Overweight and obesity are considered as chronic low-grade inflammation accompanied by imbalanced production of adipokines. The aim of this study was to elucidate the relationship between serum bilirubin, which is an endogenous antioxidant with anti-inflammatory activity, and pro- and anti-inflammatory serum adipokines in asymptomatic normal weight and overweight individuals. Healthy men and women aged 25-49 participated in this cross-sectional study. All participants underwent fasting serological measurements of adipokines, interleukin-6, tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), total and direct serum bilirubin, and other biochemical parameters. Participants were divided into normal weight and overweight groups. We found a significant negative association between total bilirubin and CRP, TNF-α, visfatin and resistin values, and a significant positive association between total bilirubin and adiponectin values in both normal weight and overweight groups. Importantly, after adjusting for body mass index, we also found a significant negative association between total serum bilirubin levels and both visfatin and CRP serum levels. Moreover, visfatin, resistin and CRP were predictors of the total serum bilirubin levels.Prekomjerna tjelesna težina i pretilost smatraju se kroničnom upalom niskog stupnja praćenom neuravnoteženom proizvodnjom adipokina. Cilj istraživačkog rada bio je razjasniti odnos između serumskog bilirubina, koji je endogeni antioksidans s protuupalnom aktivnošću, i pro- i protuupalnih serumskih adipokina kod asimptomatskih pojedinaca s normalnom i pojedinaca s prekomjernom tjelesnom težinom. U ovoj presječnoj studiji sudjelovali su zdravi muškarci i žene u dobi od 25 do 49 godina. Mjereni su biokemijski parametri, adipokini, interleukin-6 (IL-6), faktor tumorske nekroze (TNF-α), C-reaktivni protein (CRP), ukupni i direktni serumski bilirubin. Sudionici su bili podijeljeni u dvije skupine: osobe s normalnom i osobe s prekomjernom tjelesnom težinom. Pronašli smo statistički značajnu negativnu povezanost između ukupnog bilirubina i vrijednosti CRP, TNF-α, visfatina i rezistina te statistički značajnu pozitivnu povezanost između ukupnog bilirubina i adiponektina u objema skupinama. Dodatno, nakon prilagodbe indeksa tjelesne mase našli smo značajnu negativnu povezanost između ukupnog bilirubina te visfatina i CRP. Multivarijatna logistička regresijska analiza je pokazala da su visfatin, rezistin i CRP prediktori ukupnog bilirubina

Fat mass to fat- free mass ratio and body composition in participants with chronic leg problems

Background & aim: Low fat-free mass (FFM) or high fat mass (FM) in older adults are abnormal body composition phenotypes associated with morbidity. The dual burden of excessive FM and low FFM may lead to a higher risk of cardiovascular and other diseases and disability and lower physical performance compared with individuals with normal body composition or low FFM or high FM alone. Both conditions lead to poorer health and can be identified by a high FM/FFM ratio. Because few studies have examined the effects of abnormal body composition using the FM/FFM ratio, the aim of this study is to determine the FM/FFM values by gender in patients with knee and hip pathologies and compare them with body composition parameters. This condition is important when surgery is required because abnormal body composition leads to an increase in infections and other postoperative complications. Methods: A total of 93 participants aged 64.71 ± 7.71 years in women and 65.9 ± 9.9 years in men with a body mass index (BMI) ≥25 kg/m2 were recruited from the Valdoltra Orthopaedic Hospital (Ankaran, Slovenia). The waist circumference (WC) and anthropometric data (BMI), as well as body composition data (FM, FFM, % of body water, estimated by bioelectrical impedance - BIA) were measured. In addition, the body composition phenotypes (FM/FFM ratio) were calculated. Results: The FM/FFM index was higher in females. The female group with FM/FFM (0.68) and those with a higher FM/FFM (0.92) correlated positively with WC. Male participants were excluded for further analysis because only two males had FM/FFM > 0.80. The FM/FFM of the remaining male participants was 0.53 ± 0.09. Conclusions: FM/FFM provide information on patient body composition and identify individuals at risk of body composition abnormalities in women only

Intrinsic ionic conductances mediate the spontaneous electrical activity of cultured mouse myotubes

AbstractMouse skeletal myotubes differentiated in vitro exhibited spontaneous contractions associated with electrical activity. The ionic conductances responsible for the origin and modulation of the spontaneous activity were examined using the whole-cell patch-clamp technique and measuring [Ca2+]i transients with the Ca2+ indicator, fura 2-AM. Regular spontaneous activity was characterized by single TTX-sensitive action potentials, followed by transient increases in [Ca2+]i. Since the bath-application of Cd2+ (300 μM) or Ni2+ (50 μM) abolished the cell firing, T-type (ICa,T) and L-type (ICa,L) Ca2+ currents were investigated in spontaneously contracting myotubes. The low activation threshold (around −60 mV) and the high density of ICa,T observed in contracting myotubes suggested that ICa,T initiated action potential firing, by bringing cells to the firing threshold. The results also suggested that the activity of ICa,L could sustain the [Ca2+]i transients associated with the action potential, leading to the activation of apamin-sensitive SK-type Ca2+-activated K+ channels and the afterhyperpolarization (AHP) following single spikes. In conclusion, an interplay between voltage-dependent inward (Na+ and Ca2+) and outward (SK) conductances is proposed to mediate the spontaneous pacemaker activity in cultured muscle myotubes during the process of myogenesis

Wrist arthroscopy

Artroskopija ručnog zgloba je minimalno invazivna endoskopska metoda koja omogućuje dijagnosticiranje i liječenje pojedinih bolesti i ozljeda ručnog zgloba (RZ), mediokarpalnog zgloba (MKZ) i distalnog radioulnarnog zgloba (DRUZ). Ovu minimalno invazivnu kiruršku metodu prvi je opisao Yung-Cheng Chen 1979., no njezina šira primjena u kliničkoj praksi počinje tek nakon 1986., kada je Terry Lane Whipple preporučio distrakciju RZ-a i precizne lokalizacije ulaznih mjesta (portala), kako bi se učinila pravilna i potpuna evaluacija RZ-a prilikom izvođenja artroskopije. Iako je prvotno artroskopija RZ-a bila samo dijagnostička metoda, tijekom vremena, zahvaljujući kontinuiranom napretku tehnologije i uvođenju inovacija u instrumentaciji i operativnoj tehnici, artroskopija RZ-a postaje i terapeutska metoda. Cilj ovog rada prikazati je osnove o artroskopiji RZ-a, a one uključuju: povijesni razvoj, indikacije i kontraindikacije, evaluaciju i probir bolesnika za artroskopiju RZ-a na temelju anamneze, fizikalnog pregleda i slikovne obrade, pripremu za artroskopiju RZ-a, potrebnu opremu, poznavanje izvanzglobne anatomije, portale (ulazna mjesta), poznavanje unutarzglobne anatomije, preduvjete, tehniku artroskopije RZ-a, prednosti i nedostatke ove operativne metode, komplikacije i zaključak.Wrist arthroscopy is minimally invasive endoscopic procedure which enables the diagnosis and treatment of certain diseases and injuries of the wrist joint (WJ), midcarpal joints (MCJs) and distal radioulnar joint (DRUJ). This minimally invasive surgical procedure was first described by Yung-Cheng Chen in 1979. However, its widespread application in clinical practice began after 1986, when Terry Lane Whipple recommended wrist distraction and precise localization of portals to do proper and complete evaluation of the wrist when performing arthroscopy. Although initially wrist arthroscopy was only a diagnostic tool, during time due to the continuous advancement of technology and the introduction of innovations in instrumentation and surgical technique, wrist arthroscopy became a therapeutic method. The aim of this professional paper is to present the basics of wrist arthroscopy, which include: historical development, indications and contraindications, evaluation and selection of patients for wrist arthroscopy on the basis of history, physical examination and diagnostic imaging procedures, wrist arthroscopy setup, the necessary equipment, superficial anatomy, portals, intraarticular anatomy, preconditions, technique of wrist arthroscopy, the advantages and disadvantages of this surgical procedure, complications, and conclusion

Wrist arthroscopy

Artroskopija ručnog zgloba je minimalno invazivna endoskopska metoda koja omogućuje dijagnosticiranje i liječenje pojedinih bolesti i ozljeda ručnog zgloba (RZ), mediokarpalnog zgloba (MKZ) i distalnog radioulnarnog zgloba (DRUZ). Ovu minimalno invazivnu kiruršku metodu prvi je opisao Yung-Cheng Chen 1979., no njezina šira primjena u kliničkoj praksi počinje tek nakon 1986., kada je Terry Lane Whipple preporučio distrakciju RZ-a i precizne lokalizacije ulaznih mjesta (portala), kako bi se učinila pravilna i potpuna evaluacija RZ-a prilikom izvođenja artroskopije. Iako je prvotno artroskopija RZ-a bila samo dijagnostička metoda, tijekom vremena, zahvaljujući kontinuiranom napretku tehnologije i uvođenju inovacija u instrumentaciji i operativnoj tehnici, artroskopija RZ-a postaje i terapeutska metoda. Cilj ovog rada prikazati je osnove o artroskopiji RZ-a, a one uključuju: povijesni razvoj, indikacije i kontraindikacije, evaluaciju i probir bolesnika za artroskopiju RZ-a na temelju anamneze, fizikalnog pregleda i slikovne obrade, pripremu za artroskopiju RZ-a, potrebnu opremu, poznavanje izvanzglobne anatomije, portale (ulazna mjesta), poznavanje unutarzglobne anatomije, preduvjete, tehniku artroskopije RZ-a, prednosti i nedostatke ove operativne metode, komplikacije i zaključak.Wrist arthroscopy is minimally invasive endoscopic procedure which enables the diagnosis and treatment of certain diseases and injuries of the wrist joint (WJ), midcarpal joints (MCJs) and distal radioulnar joint (DRUJ). This minimally invasive surgical procedure was first described by Yung-Cheng Chen in 1979. However, its widespread application in clinical practice began after 1986, when Terry Lane Whipple recommended wrist distraction and precise localization of portals to do proper and complete evaluation of the wrist when performing arthroscopy. Although initially wrist arthroscopy was only a diagnostic tool, during time due to the continuous advancement of technology and the introduction of innovations in instrumentation and surgical technique, wrist arthroscopy became a therapeutic method. The aim of this professional paper is to present the basics of wrist arthroscopy, which include: historical development, indications and contraindications, evaluation and selection of patients for wrist arthroscopy on the basis of history, physical examination and diagnostic imaging procedures, wrist arthroscopy setup, the necessary equipment, superficial anatomy, portals, intraarticular anatomy, preconditions, technique of wrist arthroscopy, the advantages and disadvantages of this surgical procedure, complications, and conclusion