Force-, EMG-, and elasticity-velocity relationships at submaximal,maximal and supramaximal running speeds in sprinters

Summary The relationships between ground reaction forces, electromyographic activity (EMG), elasticity and running velocity were investigated at five speeds from submaximal to supramaximal levels in 11 male and 8 female sprinters. Supramaximal running was performed by a towing system. Reaction forces were measured on a force platform. EMGs were recorded telemetrically with surface electrodes from the vastus lateralis and gastrocnemius muscles, and elasticity of the contact leg was evaluated with spring constant values measured by film analysis. Data showed increases in most of the parameters studied with increasing running speed. At supramaximal velocity (10.36±0.31 m×s⁻¹; 108.4±3.8%) the relative increase in running velocity correlated significantly (P<0.01) with the relative increase in stride rate of all subjects. In male subjects the relative change in stride rate correlated with the relative change of IEMG in the eccentric phase (P<0.05) between maximal and supramaximal runs. Running with the towing system caused a decrease in elasticity during the impact phase but this was significant (P<0.05) only in the female sprinters. The average net resultant force in the eccentric and concentric phases correlated significantly (P<0.05−0.001) with running velocity and stride length in the maximal run. It is concluded that (1) increased neural activation in supramaximal effort positively affects stride rate and that (2) average net resultant force as a specific force indicator is primarily related to stride length and that (3) the values in this indicator may explain the difference in running velocity between men and women.     

Localization of [Met5]- and [Leu5]-enkephalin-like immunoreactivity in nerve terminals in human paravertebral sympathetic ganglia

Both [Leu⁵]- and [Met⁵]-enkephalin have been localized immunohistochemically in nerve fibres and in small, intensely fluorescent cells of adult human sympathetic ganglia. The nerve fibres showing enkephalin-like immunoreactivity formed a network varying in density around the sympathetic neurons, some being closely related to the perikarya. No labelled neuronal cell bodies were found. No structures within the ganglion were labelled after reaction with antibodies to vasoactive intestinal polypeptide, adrenocorticotrophin or substance P. No differences between the distributions of [Leu⁵]-and [Met⁵]-enkephalin-like immunoreactivities were found.The physiological roles of enkephalins are still unknown, but it is possible that they might act as neurotransmitters or neuromodulators in the human sympathetic nervous system.     

On lossy transform compression of ECG signals with reference to deformation of their parameter values

Electrocardiogram (ECG) signals are the most prominent biomedical signal type used in clinical medicine. Their compression is important and widely researched in the medical informatics community. In the previous literature compression efficacy has been investigated only in the context of how much known or developed methods reduced the storage required by compressed forms of original ECG signals. Sometimes statistical signal evaluations based on, for example, root mean square error were studied. In previous research we developed a refined method for signal compression and tested it jointly with several known techniques for other biomedical signals. Our method of so-called successive approximation quantization used with wavelets was one of the most successful in those tests. In this paper, we studied to what extent these lossy compression methods altered values of medical parameters (medical information) computed from signals. Since the methods are lossy, some information is lost due to the compression when a high enough compression ratio is reached. We found that ECG signals sampled at 400 Hz could be compressed to one fourth of their original storage space, but the values of their medical parameters changed less than 5% due to compression, which indicates reliable results.     

Compromised duodenal mucosal integrity in children with short bowel syndrome after adaptation to enteral autonomy

BackgroundIntestinal adaptation has been extensively studied experimentally, but very limited data is available on human subjects. In this study we assessed intestinal adaption in humans with short bowel syndrome (SBS).MethodsWe comparatively evaluated mucosal hyperplasia, inflammation, barrier function and nutrient transport using histology, immunohistochemistry and qPCR for selected 52 key genes in duodenal biopsies obtained from children with SBS after weaning off parenteral nutrition (n = 33), and matched controls without intestinal pathology (n = 12). Small bowel dilatation was assessed from contrast small bowel series.ResultsDuodenal mucosa of SBS children showed increased histologic inflammation of lamina propria (p = 0.033) and mucosal mRNA expression of tumor necrosis factor (p = 0.027), transforming growth factor (TGF)-β2 (p = 0.006) and caveolin-1 (CAV1; p = 0.001). Villus height, crypt depth, enterocyte proliferation, apoptosis and expression of proliferation and nutrient transport genes remained unchanged. Pathologic small bowel dilatation reduced crypt depth (p = 0.045) and downregulated mRNA expression of interleukin (IL)-6 by three-fold (p = 0.008), while correlating negatively with IL6 (r = -0.609, p = 0.004). Loss of ileocecal valve (ICV) upregulated mRNA expression of toll-like receptor 4 (TLR4), TGF-β1, CAV1, several apoptosis regulating genes, and mRNA expression of zonulin (p < 0.05 for all).ConclusionsDespite successful adaptation to enteral autonomy, duodenal mucosa of SBS children displayed histologic and molecular signs of abnormal inflammation and regulation of epithelial permeability, whereas no structural or molecular signs of adaptive hyperplasia or enhanced nutrient transport were observed. Excessive dilatation of the remaining small bowel paralleled impaired duodenal crypt homeostasis, while absence of ICV modified regulation of mucosal inflammation, regeneration and permeability.Level of evidenceII     

Cast immobilization in bayonet position versus reduction and pin fixation of overriding distal metaphyseal radius fractures in children under ten years of age: a case control study

PurposeCompletely displaced distal radius fractures in children have been traditionally reduced and immobilized with a cast or pin fixed. Cast immobilization leaving the fracture displaced in the bayonet position has been recently suggested as a non-invasive and effective treatment alternative. This is a pilot comparative study between reduction and no reduction.MethodsWe assessed subjective, functional and radiographic outcome after a minimum 2.5-year follow-up in 12 children under ten years of age who had sustained a completely displaced metaphyseal radius fracture, which had been immobilized leaving the fracture in an overriding position (shortening 3 mm to 9 mm). A total of 12 age-matched patients, whose similar fractures were reduced and pin fixed, were chosen for controls. ResultsAt follow-up none of the 24 patients had visible forearm deformity and the maximal angulation in radiographs was 5° Forearm and wrist movement was restored (< 10° of discrepancy) in all 24 patients. Grip strength ratio was normal in all but three surgically treated patients. All patients had returned to their previous activities. One operatively treated boy who was re-operated on reported of pain (visual analogue scale 2).ConclusionThe results of this study do not demonstrate the superiority of reduction and pin fixation over cast immobilization in the bayonet position of closed overriding distal metaphyseal radius fractures in children under ten years with normal neurovascular findings.Level of evidenceIII     

Measuring intraocular pressure with the Pulsair 3000 and Rebound tonometers in elderly patients without an anesthetic

Purpose To evaluate the utility of the new Rebound tonometer for measuring intraocular pressure (IOP) in an unanesthetized eye; to test patient tolerance, measurement time, and accuracy compared with the Pulsair 3000 tonometer.Methods IOP was measured with the Rebound tonometer and the Pulsair 3000 tonometer without an anesthetic in 131 residents of two Finnish nursing homes. The measurement time and possible pain or discomfort experienced by the inhabitants was recorded.Results The mean differences in IOP readings between the two tonometers were 0.31 mmHg, SD 2.45 mmHg for the right eyes and 0.36 mmHg, SD 2.17 mmHg for the left eyes (P=0.28, multivariate analysis). The correlation constants between the tonometers were 0.84 (right eyes) and 0.80 (left eyes). The Pulsair 3000 caused more discomfort than the Rebound tonometer (36% vs 15%, P=0.01). With the Pulsair, 85%, and with the Rebound tonometer, 95% of the patients felt no pain (P= 0.14). Measurement of both eyes with the Rebound tonometer took less time (55±22 s vs 138±55 s, P<0.001). The mean difference was 82 s and the 95% confidence interval of the difference was 66–98 s.Conclusion Measurement of IOP with the Rebound tonometer without an anesthetic is a rapid and well-tolerated procedure. IOP readings of the two tonometers were within ±1 mmHg in 52.5% of the measurements and within ±2 mmHg in 71.7% of the measurements.Submitted as an abstract to the ARVO annual meeting, May 2002     

The Effect of Severe Shot Peening on Fatigue Life of Laser Powder Bed Fusion Manufactured 316L Stainless Steel

Severe shot peening (SSP) was used on additive manufactured 316L by laser powder bed fusion. The effect of the post processing on the surface features of the material was analyzed through residual stress measurements, tensile testing, hardness-depth profiles, and fatigue testing by flexural bending. The results showed that SSP can be utilized to form residual stresses up to −400 MPa 200 μm below the surface. At the same time, a clear improvement on the surface hardness was achieved from 275 HV to near 650 HV. These together resulted in a clear improvement on material strength which was recorded at 10% improvement in ultimate tensile strength. Most significantly, the fatigue limit of the material was tripled from 200 MPa to over 600 MPa and the overall fatigue strength raised similarly from a low to high cycle regime.     

Tracheal and laryngotracheal resections and reconstructions—a single-centre experience

BackgroundSurgical resection has proven to be the most effective long-term treatment in managing airway stenoses and has shown to decrease the risk of tumor recurrence and mortality in patients with tumor infiltration to the airways. However, there are only a few Nordic reports on the results of a tracheal resection (TR) and cricotracheal resection (CTR). This study aimed to evaluate the volume and short-term outcome of TR and CTR at our institution.MethodsRetrospective review of patients who underwent TR or CTR between 2004 and 2019 at the Helsinki University Hospital (Helsinki, Finland).ResultsForty-four patients were included, of which 21 (47.7%) underwent surgery for a tumor, whereas 23 (52.3%) were operated for a benign stenosis. The most common tumor type was thyroid carcinoma with tracheal invasion (15.9%). The distance between the upper margin of the stenosis or tumor infiltration and the vocal cords was in median 3 [interquartile range (IQR), 2–5] cm and the median length of resection 2.5 (IQR, 2–3.5) cm. Overall success rate was 75% (no need for reoperation or postoperative intervention). Complications occurred in 20 (45.5%) patients, of which 10 patients were operated for a tumor, and 10 for a benign stenosis.ConclusionsTracheal and CTRs were effective in treating tracheal and subglottic stenoses with variable etiology. However, complications were common especially following cricotracheal tumor resections. These procedures show a clear need for further centralization due to their complex nature and should therefore be performed primarily at institutes with highly experienced multi-professional teams.     

The effect of tightened hearing protection regulations on military noise-induced tinnitus

The objective of this study was to investigate the effect of tightened hearing protection regulations on tinnitus in the Finnish Defence Forces. The initial study group comprised 252 officers and non-commissioned officers (NCOs), of which 229 were included in the final study group. Subjective symptoms of tinnitus and audiometric test results for these officers and NCOs examined before retirement, from 1984 to 1986 (Period I), and 2003 to 2005 (Period II), were reviewed. Changes in tinnitus reports between the two time periods, during which regulations had been revised, were investigated. Prevalence of tinnitus showed a decline both in officers (from 68% to 63%) and in NCOs (from 76% to 72%) between the two study periods, in accordance with tightened hearing protection regulations. The Cox regression analysis showed a significantly decreased hazard ratio for constant or disturbing tinnitus for Period II. Tinnitus prevalence, especially constant or disturbing tinnitus, in the Finnish Defence Forces was diminished by tightened hearing protection regulations. Tinnitus might be more persistent than hearing loss and does not necessarily improve in direct relation to hearing loss after protective measures.