Safeness and efficacy of 2-µm handheld thulium laser during microsurgical resection of supratentorial and infratentorial meningiomas: Experience of a single center

AimsWe performed a retrospective nonrandomized study to analyze the results of a microsurgery of intracranial meningiomas using 2-μm thulium flexible handheld laser fiber (Revolix jr).MethodsFrom February 2014 to December 2021, 75 nonconsecutive patients suffering from intracranial meningiomas, admitted in our department, have been operated on with microsurgical technique assisted by 2-μm thulium flexible handheld laser. We have reviewed demographic and clinical data to evaluate safety and efficacy of the technique.ResultsThere were no complications related to the use of the 2-μm thulium laser. We operated on a high percentage of cranial base and tentorial and posterior fossa meningioma in our series. The neurological outcome and degree of resection did not differ from previous series. The neurosurgical team found the laser easy to use and practical for avoiding bleeding and traction.ConclusionThe use of 2-μm thulium fiber handheld flexible laser in microsurgery of intracranial meningiomas seems to be safe and to facilitate tumor resection, especially in “difficult” conditions (e.g., deep seated, highly vascularized, and hard tumors). Even if in this limited retrospective trial the good functional outcome following conventional microsurgery had not further improved, nor the surgical time was reduced by laser, focusing its use on “difficult” (large and vascularized) cases may lead to different results in the future

Vestibular Schwannomas Microsurgery Assisted by Flexible Hand-Held 2 micro-Thulium-Fiber Laser

Background: Vestibular Schwannoma (VS) is one of the skull base tumors originating from vestibular portion of eighth cranial nerve. Recently, 2 micro-Thulium laser is used in the surgery of some intracranial tumors. Objectives: Assessing the efficacy of 2 micro-Thulium flexible hand-held laser fiber (RevolixjrÒ) in microsurgical removal of VS. Materials and Methods: This retrospective non-randomized study was carried out from July 2012 to November 2015. 39 patients with VS had been operated on with microsurgical technique via retro-sigmoid approach. 2 micro-Thulium-fiber hand-held flexible laser was used for tumor resection in 39 cases. Facial nerves function by House-Brackmann (HB) scale and hearing state were assessed preoperatively and 1 week and 6-month postoperatively. Results: Overall time of surgery changed only in proportion with the size of tumor (185-575 minutes) and was not affected by the use of laser. In 5out of 39cases, preoperative facial nerve palsy HB2, and in one case HB4 (permanent) was observed. On considering 38 cases, at 6-month follow-up facial nerve preservation rate (HB1) was 92.1% (from May 2015 all patients had not postoperative facial palsy). Hearing preservation rate was possible in 12 out of 15 cases with previously acceptable preoperative hearing state (AAO-HNS A and B classes). The mean surgeon satisfaction rate of usefulness of this technic was 2.7 in a 0-3-scale Conclusions: A good functional outcome including facial nerve preservation and hearing preservation was obtained by micro-Thulium-fiber hand-held flexible laser microsurgery

Outbreak of fatal nitrate toxicosis associated with consumption of fennels (Foeniculum vulgare) in cattle farmed in Campania Region (Southern Italy)

Nitrate and nitrite are toxicants which have become increasingly significant environmental chemicals. An increase in environmental distribution of nitrogenous compounds, especially in surface and ground water has been attributed to the intensive use of nitrate as agricultural fertilizers and to increasing amounts of nitrogenous wastes produced by municipalities, industries and feedlots. The purpose of this study is to illustrate a fatal nitrate toxicosis in cattle associated with the consumption of fennels (Foeniculum vulgare). Fifteen cows from the same farm suddenly developed weakness, muscular tremors, respiratory distress and finally anoxic convulsions. Affected animals died within 24 to 48 hours from the onset of the clinical signs. Five cows underwent a complete post-mortem examination. In all examined animals, gross lesions included presence of dark uncoated blood around the nostrils and the anal region, moderate inflammation of the gastrointestinal mucosa, and brown discoloration of the skeletal muscles and kidneys. The histological examination showed tubular degeneration and congestion of glomerular vessels in the kidney. Toxicological analysis detected high levels of nitrates in the fennels used to feed the animals. The source of exposure to nitrates was identified in the fennels. The fennels were grown in a polluted area of Campania region and distributed in a public market for human consumption. The waste from the sale of the fennels were collected and fed the cows. The accumulation of nitrates in some vegetables pose a risk not only for animal health but also for human and environmental safety

Effective antibodies immobilization and functionalized nanoparticles in a quartz-crystal microbalance-based immunosensor for the detection of parathion.

BACKGROUND:Biosensor-based detection provides a rapid and low-cost alternative to conventional analytical methods for revealing the presence of the contaminants in water as well as solid matrices. Although important to be detected, small analytes (few hundreds of Daltons) are an issue in biosensing since the signal they induce in the transducer, and specifically in a Quartz-Crystal Microbalance, is undetectable. A pesticide like parathion (M = 292 Da) is a typical example of contaminant for which a signal amplification procedure is desirable. METHODS/FINDINGS:The ballasting of the analyte by gold nanoparticles has been already applied to heavy target as proteins or bacteria to improve the limit of detection. In this paper, we extend the application of such a method to small analytes by showing that once the working surface of a Quartz-Crystal Microbalance (QCM) has been properly functionalized, a limit of detection lower than 1 ppb is reached for parathion. The effective surface functionalization is achieved by immobilizing antibodies upright oriented on the QCM gold surface by a simple photochemical technique (Photonic Immobilization Technique, PIT) based on the UV irradiation of the antibodies, whereas a simple protocol provided by the manufacturer is applied to functionalize the gold nanoparticles. Thus, in a non-competitive approach, the small analyte is made detectable by weighing it down through a "sandwich protocol" with a second antibody tethered to heavy gold nanoparticles. The immunosensor has been proved to be effective against the parathion while showing no cross reaction when a mixture of compounds very similar to parathion is analyzed. CONCLUSION/SIGNIFICANCE:The immunosensor described in this paper can be easily applied to any small molecule for which polyclonal antibodies are available since both the functionalization procedure of the QCM probe surface and gold nanoparticle can be applied to any IgG, thereby making our device of general application in terms of target analyte

The projection of a model Au-NP functionalized with Abs consists of a circle, which is the projection of the gold nanoparticle and of different segments associated to the T shape of the antibodies.

<p>We estimate the area occupied by the functionalized particle on the sensor as that of the convex hull of these geometrical objects. The mean occupied area is obtained by averaging over different randomly functionalized nanoparticles.</p

Absorption spectra of a solution containing 180 μg/mL of polyclonal antibody against parathion measured before (continuous black line) and after the functionalization of the Au-NPs (dashed red line).

<p>Absorption spectra of a solution containing 180 μg/mL of polyclonal antibody against parathion measured before (continuous black line) and after the functionalization of the Au-NPs (dashed red line).</p

Sensorgram showing the output of the QCM, which includes the functionalization (steps I-III) and the measurement (steps IV-VI) of parathion at 290 μg/L.

<p>I: functionalization by PIT (Abs are tethered to the probe surface); II: the washing by PBS solution (1x) removes unspecific bonds giving rise to a small increase of the frequency; III: BSA is conveyed to the cell and no frequency change is observed warranting the full coverage of the surface: IV: parathion is injected, but no frequency change is observed because of its small mass; V: the injection of the Au-NPs complexed with Abs against parathion yields a huge frequency change; VI: the eventual washing with PBS (1x) does not change the frequency since all the bonds are specific.</p

Schematic principle of the measurement procedure.

<p>a) The irradiated Abs are tethered right-up onto the gold electrode, thereby being able to recognize the analyte with large effectiveness [panel b)]. c) The detection of the light analyte takes place by ballasting it in a specific way through secondary Abs linked to Au-NP.</p