Electromyographic Assessment of Anterior Cruciate Ligament Injury Risk in Male Tennis Players: Which Role for Visual Input? A Proof-of-Concept Study.

Anterior cruciate ligament (ACL) injury incidence is often underestimated in tennis players, who are considered as subjects conventionally less prone to knee injuries. However, evaluation of the preactivation of knee stabilizer muscles by surface electromyography (sEMG) showed to be a predictive value in the assessment of the risk of ACL injury. Therefore, this proof-of-concept study aimed at evaluating the role of visual input on the thigh muscle preactivation through sEMG to reduce ACL injury risk in tennis players. We recruited male, adult, semiprofessional tennis players from July to August 2020. They were asked to drop with the dominant lower limb from a step, to evaluate-based on dynamic valgus stress-the preactivation time of the rectus femoris (RF), vastus medialis, biceps femoris, and medial hamstrings (MH), through sEMG. To highlight the influence of visual inputs, the athletes performed the test blindfolded and not blindfolded on both clay and grass surfaces. We included 20 semiprofessional male players, with a mean age 20.3 ± 4.8 years; results showed significant early muscle activation when the subject lacked visual input, but also when faced with a less-safe surface such as clay over grass. Considering the posteromedial-anterolateral relationship (MH/RF ratio), tennis players showed a significant higher MH/RF ratio if blindfolded (22.0 vs. 17.0% not blindfolded; p < 0.01) and percentage of falling on clay (17.0% vs. 14.0% in grass; p < 0.01). This proof-of-principle study suggests that in case of absence of visual input or falling on a surface considered unsafe (clay), neuro-activation would tend to protect the anterior stress of the knee. Thus, the sEMG might play a crucial role in planning adequate athletic preparation for semiprofessional male athletes in terms of reduction of ACL injury risk.

In vivo tumor detection in small animals by hematoporphyrin-mediated fluorescence imaging.

OBJECTIVE: Noninvasive in vivo imaging of human tumors implanted in mice provides a reliable and economic tool for the investigation of tumor progression and metastasis and of the effectiveness of the antiblastic drugs on them. The purpose of this study is to report on the performance achievable by the well-known and extensively investigated HP-FRI (HematoPorphyrin (HP)-mediated Fluorescence Reflectance Imaging) when a high-quality image-acquisition device is used. BACKGROUND DATA: Previous articles of ours showed that HP-FRI still represents a useful, simple and reliable optical imaging technique to detect surface tumors. Therefore, it is particularly suitable to be used in combination with other imaging modalities in a multimodal imaging system endowed with diagnostic capabilities much better than each separate modality. MATERIALS AND METHODS: Six-week-old Crl:CD-1 nude mice were subcutaneously inoculated with tumor cells. Tumor-bearing mice were irradiated in vivo by a frequency-doubled pulsed Nd:YAG laser (lambda = 532 nm). A cooled CCD digital camera recorded fluorescence light emitted by HP injected in mice through a cut-on long-wavelength pass filter. RESULTS: The system we developed allows in vivo imaging of surface tumors on small animals with a large field of view, high photometric sensitivity, adequate space resolution, and short measurement time. The estimated spatial resolution is 730 microm for a fluorescence source placed about 0.5 mm under the mouse skin. The first exploration of the capabilities of this HP-FRI setup on few mice shows that it allows the detection of (a) both types of investigated tumors, (b) early stage and late stage but visually unrecognizable tumors, (c) the gross structure of tumors, and (d) the discrimination of necrotic and nonnecrotic tumor regions.

Hematoporphyrin-mediated fluorescence reflectance imaging: application to early tumor detection in vivo in small animals.

The in vivo early detection of subcutaneous human tumors implanted in small animals was studied by laser-induced fluorescence reflectance imaging (FRI), with a hematoporphyrin (HP) compound as an exogenous optical contrast agent. Tumor detection was shown to be possible just 3 days after the inoculation of tumor cells, when tumors were neither visible nor palpable. However, this detection capability is limited to a temporal window of approximately 100 h from HP administration and to a low optical contrast of the tumor (<2).

Low temperature method for the production of calcium phosphate fillers.

BACKGROUND: Calcium phosphate manufactured samples, prepared with hydroxyapatite, are used as either spacers or fillers in orthopedic surgery, but these implants have never been used under conditions of mechanical stress. Similar conditions also apply with cements. Many authors have postulated that cements are a useful substitute material when implanted in vivo. The aim of this research is to develop a low cristalline material similar to bone in porosity and cristallinity. METHODS: Commercial hydroxyapatite (HAp) and monetite (M) powders are mixed with water and compacted to produce cylindrical samples. The material is processed at a temperature of 37-120 degrees C in saturated steam to obtain samples that are osteoconductive. The samples are studied by X-ray powder diffraction (XRD), Vickers hardness test (HV), scanning electron microscopy (SEM), and porosity evaluation. RESULTS: The X-ray diffractions of powders from the samples show patterns typical of HAp and M powders. After thermal treatment, no new crystal phase is formed and no increase of the relative intensity of the peaks is obtained. Vicker hardness data do not show any relationship with treatment temperature. The total porosity decreases by 50-60% according to the specific thermal treatment. Scanning electron microscopy of the surfaces of the samples with either HAp 80%-M 20% (c) or Hap 50%-M 50% (f), show cohesion of the powder grains. CONCLUSIONS: The dissolution-reprecipitation process is more intesive in manufactured samples (c) and (f), according to Vickers hardness data. The process occurs in a steam saturated environment between 37 degrees and 120 degrees C. (c) (f) manufactured samples show pore dimension distributions useful to cellular repopulation in living tissues.