Design and Test of a Biomechanical Model for the Estimation of Knee Joint Angle During Indoor Rowing: Implications for FES-Rowing Protocols in Paraplegia

Functional electrical stimulation of lower limb muscles during rowing provides a means for the cardiovascular conditioning in paraplegia. The possibility of shaping stimulation profiles according to changes in knee angle, so far conceived as changes in seat position, may help circumventing open issues associated with muscle fatigue and movement coordination.Here we present a subject-specific biomechanical model for the estimation of knee joint angle during indoor rowing. Anthropometric measurements and foot and seat position are inputs to the model. We tested our model on two samples of elite rowers; 15 able-bodied and 11 participants in the Rio 2016 Paralympic games. Paralympic rowers presented minor physical disabilities (LTA-PD classification), enabling them to perform the full rowing cycle (with legs, trunks and arms). Knee angle was estimated from the rowing machine seat position, measured with a linear encoder and transmitted wirelessly to a computer. Key results indicate the root mean square error (RMSE) between estimated and measured angles did not depend on group and stroke rate (p>0.267). Significantly greater RMSE values were observed however within the rowing cycle (p<0.001), reaching on average 8deg in the mid-recovery phase. Differences between estimated and measured knee angle values resulted in slightly earlier (5%) detection of knee flexion, regardless of the group and stroke rate considered. Offset of knee extension, knee angle at catch and range of knee motion were identified equally well with our model and with inertial sensors. These results suggest our model describes accurately the movement of knee joint during indoor rowing

Nimodipine in otolaryngology: from past evidence to clinical perspectives

As L-type voltage-gated calcium channels (VGCCs) control Ca(2+) influx and depolarisation of cardiac and vascular smooth muscle, they represent a specific therapeutic target for calcium channel blockers (CCBs), which are approved and widely used to treat hypertension, myocardial ischaemia and arrhythmias. L-type currents also play a role in calcium entry in the sensory cells of the inner ear. In hair cells of both cochlea and labyrinth, calcium cytoplasmic influx is the first physiological process that activates complex intracellular enzymatic reactions resulting in neurotransmitter release. Excessive calcium ion entry into sensory cells, as a consequence of L-VGCCs malfunction is responsible for over-activation of phospholipase A2 and C, protein kinase II and C, nitric oxide synthase and both endonucleases and depolymerases, which can cause membrane damage and cellular death if the cytoplasmic buffering capacity is overcome. Nimodipine, a highly lipophilic 1-4 dihydropyridine that easily crosses the brain-blood barrier, is generally used to reduce the severity of neurological deficits resulting from vasospasm in patients with subarachnoid haemorrhage. Moreover, due to its selective blocking activity on L-channel calcium currents, nimodipine is also suggested to be an effective countermeasure for cochlear and vestibular dysfunctions known as channelopathies. Indeed, experimental data in amphibians and mammalians indicate that nimodipine has a stronger efficacy than other CCBs (aminopyridine, nifedipine) on voltage-dependent whole-cell currents within hair cells at rest and it is the only agent that is also effective during their mechanically induced depolarisation. In humans, the efficacy of nimodipine is documented in the medical management of peripheral vestibular vertigo, sensorineural hearing loss and tinnitus, even in a pathology as complex as Ménière's disease. Nimodipine is also considered useful in the prophylaxis of damage to the facial and cochlear nerves caused by ablative surgery of cerebellopontine tumours; it has been recently hypothesised to accelerate functional recovery of recurrent nerve lesions during thyroid cancer surgery. Further trials with adequate study design are needed to test the efficacy of nimodipine in the treatment of vertigo due to cerebrovascular disease and vestibular migraine.As L-type voltage-gated calcium channels (VGCCs) control Ca(2+) influx and depolarisation of cardiac and vascular smooth muscle, they represent a specific therapeutic target for calcium channel blockers (CCBs), which are approved and widely used to treat hypertension, myocardial ischaemia and arrhythmias. L-type currents also play a role in calcium entry in the sensory cells of the inner ear. In hair cells of both cochlea and labyrinth, calcium cytoplasmic influx is the first physiological process that activates complex intracellular enzymatic reactions resulting in neurotransmitter release. Excessive calcium ion entry into sensory cells, as a consequence of L-VGCCs malfunction is responsible for over-activation of phospholipase A2 and C, protein kinase II and C, nitric oxide synthase and both endonucleases and depolymerases, which can cause membrane damage and cellular death if the cytoplasmic buffering capacity is overcome. Nimodipine, a highly lipophilic 1-4 dihydropyridine that easily crosses the brain-blood barrier, is generally used to reduce the severity of neurological deficits resulting from vasospasm in patients with subarachnoid haemorrhage. Moreover, due to its selective blocking activity on L-channel calcium currents, nimodipine is also suggested to be an effective countermeasure for cochlear and vestibular dysfunctions known as channelopathies. Indeed, experimental data in amphibians and mammalians indicate that nimodipine has a stronger efficacy than other CCBs (aminopyridine, nifedipine) on voltage-dependent wholecell currents within hair cells at rest and it is the only agent that is also effective during their mechanically induced depolarisation. In humans, the efficacy of nimodipine is documented in the medical management of peripheral vestibular vertigo, sensorineural hearing loss and tinnitus, even in a pathology as complex as Ménière's disease. Nimodipine is also considered useful in the prophylaxis of damage to the facial and cochlear nerves caused by ablative surgery of cerebellopontine tumours; it has been recently hypothesised to accelerate functional recovery of recurrent nerve lesions during thyroid cancer surgery. Further trials with adequate study design are needed to test the efficacy of nimodipine in the treatment of vertigo due to cerebrovascular disease and vestibular migraine

The Terracol and Ardouin developmental model of frontal sinus drainage pathway and surrounding spaces: a radiologic validation

The complexity of the frontal sinus drainage pathway (FSDP) can be challenging even for expert surgeons. Several classifications have been proposed to simplify the understanding of FSDP, whose anatomical variability can be simplified based on the knowledge of its developmental mechanisms

Rivascolarizzazione pulpare in seguito a reimpianto dentale: caso clinico.

INTRODUZIONE E SCOPO DELLO STUDIO In seguito ad avulsione dentaria il processo di guarigione del fascio vascolo-nervoso determina il piano terapeutico.Studi effettuati sulla reazione della polpa hanno permesso di identificare diversi processi di guarigione.Numerosi studi eseguiti hanno portato ad osservare la formazione di tessuto duro lungo le pareti dentinali circa 17 giorni dopo il reimpianto; mentre si osservano nuove fibre nervose circa un mese dopo. Studi di tipo microangiografico hanno dimostrato la presenza di nuovi vasi già a 4 giorni dal reimpianto; dopo 10 giorni sono stati rilevati vasi nel terzo apicale e dopo 30 giorni nell’intera camera pulpare. Lo scopo di questo studio è quello di presentare un caso clinico di rivascolarizzazione pulpare in seguito a reimpianto.MATERIALI E METODI Il paziente, di 8 anni, presenta entrambi gli incisivi centrali superiori avulsi in seguito ad un incidente sportivo.Giunge all’osservazione 30 minuti dopo il trauma, con gli elementi dentari conservati in soluzione fisiologica sin dai primi istanti. Entrambi gli elementi presentano apice beante e non completa formazione della radice.Seguendo le linee guida della IADT si decide di reimpiantare gli elementi e di eseguire uno splintaggio semi-flessibile.Si eseguono successivi controlli clinici e radiografici a 1-3-6 e 12 mesi.CONCLUSIONI Nei denti con incompleta formazione radicolare è possibile andare incontro a rivascolarizzazione; tuttavia i test elettrici e termici non sono affidabili in seguito a traumi dentali, in quanto possono dare falsi negativi. La valutazione clinica di un dente traumatizzato però richiede uno studio sintomatico, visivo e radiografico. Se il dente diviene necrotico o infetto si può andare incontro ad un processo di riassorbimento radicolare che può condurre alla perdita del dente in breve tempo.Una diminuzione della dimensione della camera pulpare o del canale radicolare sull’immagine radiografica è un segno affidabile della vitalità pulpare.Il caso discusso rappresenta la possibilità di rivascolarizzazione in seguito a reimpianto a breve termine

Thick tori around AGN: the case for extended tori and consequences for their X-ray and IR emission

Two families of models of dusty tori in AGNs (moderately thick and extended versus very thick and compact) are tested against available observations. The confrontation suggests that the former class better explains the IR broad-band spectra of both broad and narrow line AGNs, the anisotropy of the emission deduced by comparing IR properties of Seyfert 1 and 2 nuclei, the results of IR spectroscopy and those of high spatial resolution observations. There is however clear evidence for a broad distribution of optical depths. We also examine the relationship between IR and X-ray emission. The data support a view in which the matter responsible for the X-ray absorption is mostly dust free, lying inside the dust sublimation radius. The consequences of these results for the hard X-ray background as well as IR counts and background are discussed.Comment: 33 pages, 9 Postscript figures, to appear in ApJ, September 199

Electrodes' Configuration Influences the Agreement Between Surface EMG and B-Mode Ultrasound Detection of Motor Unit Fasciculation

Muscle fasciculations, resulting from the spontaneous activation of motor neurons, may be associated with neurological disorders, and are often assessed with intramuscular electromyography (EMG). Recently, however, both ultrasound (US) imaging and multichannel surface EMG have been shown to be more sensitive to fasciculations. In this study we combined these two techniques to compare their detection sensitivity to fasciculations occurring in different muscle regions and to investigate the effect of EMG electrodes' configuration on their agreement. Monopolar surface EMGs were collected from medial gastrocnemius and soleus with an array of 32 electrodes (10 mm Inter-Electrode Distance, IED) simultaneously with b-mode US images detected alongside either proximal, central or distal electrodes groups. Fasciculation potentials (FP) were identified from single differential EMGs with 10 mm (SD1), 20 mm (SD2) and 30 mm (SD3) IEDs, and fasciculation events (FE) from US image sequences. The number, location, and size of FEs and FPs in 10 healthy participants were analyzed. Overall, the two techniques showed similar sensitivities to muscle fasciculations. US was equally sensitive to FE occurring in the proximal and distal calf regions, while the number of FP revealed by EMG increased significantly with the IED and was larger distally, where the depth of FE decreased. The agreement between the two techniques was relatively low, with a percentage of fasciculation classified as common ranging from 22% for the smallest IED to 68% for the largest IED. The relevant number of events uniquely detected by the two techniques is discussed in terms of different spatial sensitivities of EMG and US, which suggest that a combination of US-EMG is likely to maximise the sensitivity to muscle fasciculations

The anastomotic network around the anterior superior alveolar nerve: an anatomical and radiological study

Innervation of superior teeth is supplied by the posterior (PSAN), anterior (ASAN) and sometimes by middle superior alveolar nerve (MSAN). PSAN arises from the maxillary nerve and passes through the posterolateral maxillary wall towards the posterior teeth. ASAN arises from the anterior portion of the infraorbital nerve and courses within the infraorbital canal passing nearby the piriform aperture and premaxilla. When present, MSAN arises from the posterior portion of the infraorbital nerve and runs along the lateral maxillary wall. However, an additional nasopalatine or sublabial injection is frequently required to obtain a complete anesthesia of the maxillary teeth due to rich anastomotic network (1-2). With the aim to better describe the complexity of the superior alveolar nerve network, fifty-seven high-definition sinonasal cone-beam CT (CBCT) were analyzed. PSAN, ASAN and MSAN were detected by specific bony landmarks/canals and nervous anastomoses were accurately evaluated. In addition, medial anastomotic branches from the palatal and/or nasal nervous plexi were also considered. PSAN and ASAN were identified in 100% of cases whereas MSAN in 19.6% of cases. Anastomotic branch versus ASAN was identified in all cases from MSAN and in 60.3% from PSAN. Medial anastomotic branch was detected in 62.0% of cases from the nasal plexus and in 6.2% from the palatal plexus: the former passed through a bony defect in the floor of the piriform aperture or at the base of the nasal septum; the latter passed through a tiny canal in the interface between maxilla and premaxilla. These data confirm that maxillary teeth innervation, especially for incisor teeth, could be provided not only by alveolar nerves but also from palatal and nasal plexi via small branches running within maxillary bony canals. These results support the need of additional anesthetic injection to obtain adequate anesthesia of the maxillary teeth; moreover, the role of CBCT in the identification of the nervous pattern was underlined