Notes

Tetrazoles: Exclusive Capping Ligands and also Precursors regarding Nanostructured Materials.
The Elekta Unity MR-Linac (MRL) is expected to benefit spine stereotactic body radiotherapy (SBRT) due to the improved soft tissue contrast available with onboard MR imaging. However, the irradiation geometry and beam configuration of the MRL deviates from the conventional linear accelerator (Linac). The purpose of the study was to investigate the feasibility of spine SBRT on the MRL. Treatment plans were generated for lumbar and thoracic spines. Target and spinal cord doses were measured with two cylindrical ion chambers inserted into an anthropomorphic spine phantom. Our study indicated that the Monaco treatment planning system (TPS) could generate clinical treatment plans for the MRL that were of comparable quality to the RayStation TPS with a conventional Linac. For both Linacs the planned dose within the gross tumor volume agreed with measurements within ±3%. For the spinal cord, while the measured doses from the TrueBeam were 1.8% higher for the lumbar spine plan and 6.9% higher for thoracic spine plan, the measured doses from MRL were 0.6% lower for the lumbar spine plan and 3.9% higher for the thoracic spine plan. In conclusion, the feasibility of spine SBRT in Elekta Unity MRL has been demonstrated, however, more effort is needed for such as optimizing the online plan adaptation method.This risk analysis describes our Failure Mode and Effects Analysis (FMEA) for Gamma Knife stereotactic radiosurgery at our community hospital. During bi-monthly meetings over 5 months, our FMEA team mapped a detailed Gamma Knife process tree and identified potential failure modes, each were scored a Risk Priority Number (RPN) for severity, occurrence, detectability. In our process tree of 14 subprocesses and 177 steps, we identified 31 potential failure modes 7 high scoring (RPN o150) and 3 modes ( less then 150) selected by clinicians for mitigation strategies. Eighteen months later, rescoring of high-risk failure modes showed significant reduction in RPN scores, thus confirming the benefit of our FMEA mitigation strategies. Our study provides a roadmap to achieve high-quality Gamma Knife radiosurgery that can be utilized by new centers as a starting point for their quality management program. Five quality control documents were developed that can be customized by any Gamma Knife center.Introduction Two-staged stereotactic radiosurgery (SRS) has been shown as an effective treatment for brain metastases that are too large for single fraction SRS. Methods Patients with large brain metastases (>4 cm3) treated with two-staged SRS from January 2017 to December 2019 at our institution were retrospectively identified. Results There were 23 brain metastases treated. The normal brain volume receiving equivalent 12Gy-in-single-fraction was defined as V12E. The V12E for original single-fraction GKS plan (mean of 41.4 cm3, range 5.6-146.1 cm3) was significantly higher compared to that of the second stage (mean of 23.7 cm3, range 2.8-92.7 cm3). The median tumor volume measured at the second stage (4.30 cm3) was reduced by an average of 52.2% compared to the first stage (9.58 cm3). Three patients (27.3%) showed local tumor progression in 4 tumors (20%). The median time to progression was 152 days. Conclusions Two-staged SRS is an effective treatment technique for large brain metastasis that results in significant reduction of tumor volume at the second stage SRS. Optimal treatment dose has not yet been defined.Background This study compares the outcomes of stereotactic body radiation therapy (SBRT) for sacral and thoracolumbar spine metastases. Methods This analysis considered each sacral spine SBRT treatment at a single institution and a cohort of consecutive thoracolumbar treatments. Results 28 patients with 35 sacral treatments and 41 patients with 49 thoracolumbar treatments were included. Local control was 63% and 90%, respectively. The sacral cohort contained more lesions with ≥2 vertebrae and epidural and paraspinal involvement. Sacral patients had larger treatment volumes, increased rates of subsequent SBRT, decreased propensity for pain improvement, and decreased local control (p=0.02 on Kaplan-Meier analysis). Multivariate analysis demonstrated that PTV > 50 cc and epidural involvement were correlated with decreased local control. No cases had grade ≥3 toxicity. Conclusion SBRT for sacral spine metastases is a distinct disease process than metastases to the thoracolumbar spine, resulting in lower rates of local control and pain improvement.We sought to evaluate the association between larynx dose and risk of severe late laryngeal toxicity in patients undergoing re-irradiation SBRT for recurrent HNC. Fifty-five patients with an intact larynx underwent re-irradiation SBRT to a median dose of 44 Gy in 5 fractions. Five (41.7%) patients treated for a laryngeal/hypopharyngeal recurrence experienced late grade ≥3 laryngeal toxicity, compared to 0.0-7.1% for other sites. Logistic dose-response models were created to predict risk of severe late laryngeal toxicity, including dysphagia and airway compromise. According to the model, the risk of severe laryngeal toxicity with a larynx D5cc of 5 Gy is 5.8% (95% CI 2.9-9.9%) and rises to 11.4% with a D5cc of 20 Gy and 25.3% with a D5cc of 40 Gy. In patients with a laryngeal/hypopharyngeal recurrence, SBRT planning should carefully assess the dose to laryngeal structures given these dose findings, and SBRT should be approached with significant caution in such patients.Iron is an especially important redox-active cofactor in biology because of its ability to mediate reactions with atmospheric O2. Iron-dependent oxygenases exploit this earth-abundant transition metal for the insertion of oxygen atoms into organic compounds. Throughout the astounding diversity of transformations catalyzed by these enzymes, the protein framework directs reactive intermediates toward the precise formation of products, which, in many cases, necessitates the cleavage of strong C-H bonds. In recent years, members of several iron-dependent oxygenase families have been engineered for new-to-nature transformations that offer advantages over conventional synthetic methods. In this Perspective, we first explore what is known about the reactivity of heme-dependent cytochrome P450 oxygenases and nonheme iron-dependent oxygenases bearing the 2-His-1-carboxylate facial triad by reviewing mechanistic studies with an emphasis on how the protein scaffold maximizes the catalytic potential of the iron-heme and iron cofactors. We then review how these cofactors have been repurposed for abiological transformations by engineering the protein frameworks of these enzymes. Finally, we discuss contemporary challenges associated with engineering these platforms and comment on their roles in biocatalysis moving forward.While biocatalysis is increasingly incorporated into drug development pipelines, it is less commonly used in the early stages of drug discovery. C75 By engineering a protein to produce a chiral motif with a derivatizable functional handle, biocatalysts can be used to help generate diverse building blocks for drug discovery. Here we show the engineering of two variants of Rhodothermus marinus nitric oxide dioxygenase (RmaNOD) to catalyze the formation of cis- and tran- diastereomers of a pinacolboronate-substituted cyclopropane which can be readily derivatized to generate diverse stereopure cyclopropane building blocks.
Occipital transtentorial approach for selected posterior third ventricular or retrosplenium region tumors provides an ergonomic and safe access. Over centuries, the opponents of this approach highlight the problem of postoperative visual field defect, related to the retraction of occipital lobe. The aim was to describe the surgical nuances of gravity-assisted retractor-less occipital-transtentorial approach (GAROTA) as a modification of originally described GAROTA to minimize the complications with a similar ease of surgery.

In this study, we have retrospectively analyzed our prospectively maintained surgical databases of patients operated by occipito-transtentorial from 2015 to 2019. Demographic variables, preoperative and postoperative neurological deficits (especially visual field defect) were analyzed. Radiological data included relation of veins with tumor, presence of hydrocephalus, size, and extent of lesion.

Fifteen patients underwent GAROTA (right-sided extension,
= 7; left-sided extension,
= 4; and midline lesions,
= 4). Headaches (73.3%) and diplopia (40%) were the most common symptoms. No patient had any postoperative visual deficits in both short-term and long-term follow-up.

A thorough anatomical knowledge of posterior third interhemispheric region in the semi-prone position is required for GAROTA. Meticulous arachnoid dissection around the deep venous complex and release of cerebrospinal fluid through the cisterns is required. Postoperative cortical vision loss may be prevented by following the key surgical principles in GAROTA.
A thorough anatomical knowledge of posterior third interhemispheric region in the semi-prone position is required for GAROTA. Meticulous arachnoid dissection around the deep venous complex and release of cerebrospinal fluid through the cisterns is required. Postoperative cortical vision loss may be prevented by following the key surgical principles in GAROTA.
We describe the technical report and results of the first image-guided, linear accelerator, frameless radiosurgical third ventriculostomy.

We report a 20 years old man, with diplopia, balance disturbances, and limitation for gaze supraversion. Magnetic resonance imaging resonance imaging of the brain and cranial computed tomography showed showed a left thalamic-midbrain lesion that caused partial compression of the Silvio aqueduct and mild ventricular dilatation. The biopsy revealed the diagnosis of pleomorphic xanthoastrocytoma. Before radical treatment of the tumor with fractionated stereotactic radiotherapy, the patient underwent to frameless radiosurgical third ventriculostomy, on the TrueBeam STX® platform with the ExacTrac localization system. The target used was the one defined on the floor of the third ventricle, at the midpoint between the mammillary bodies and the infundibular recess. The prescription dose was 120 Gy, given using a monoisocentric technique of multiple noncoplanar circular arches. The geometric arrangement of the plan consisted of 15 arches, with a 4 mm cone, distributed over a 110° table.

There was symptomatic and image improvement two days after radiosurgery. On CT, a reduction in ventricular dilation was observed with a reduction in the Evans index from 0.39 (initial CT) to 0.29 (CT at 15 days). In 3.0T magnetic resonance image at 3 months, we showed the third ventriculostomy. There have been no treatment failures or complications.

It is possible to effectively perform the frameless radiosurgical third ventriculostomy without associated morbidity in the short term.
It is possible to effectively perform the frameless radiosurgical third ventriculostomy without associated morbidity in the short term.
Intracranial aneurysms are common vascular malformation occurring in 1-2% of the population and accounting for 80-85% of nontraumatic subarachnoid hemorrhages. About 10% of the ruptured aneurysm causing subarachnoid hemorrhage (SHA) develop intraventricular hemorrhage (IVH). In this scenario, the external ventricular drain (EVD) is a usual treatment for IVH. To reduce the time for the clot absorption, the neuroendoscopy with clot removal and ventricular irrigation is a feasible option, although not routinely used.

This 2D video shows a case of a 60-year-old female, with sudden headache associated with nausea and vomit. The brain angiotomography revealed aneurysm in the communicating segment of the left internal carotid artery, with 10.5 mm of diameter; also showed intraparenchymal, subarachnoid, and IVH, with a Fisher Modified Grade of 4 and a prompt aneurysm clipping and EVD were performed. Two days after the first surgical procedure, a neuroendoscopy was performed to remove the ventricular clots and improve the patient outcomes.
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