Phosphorylation of Oligopeptides: Design of Ultra-Hydrophilic Zwitterionic Peptides for Anti-Fouling Detection of Nucleic Acids in Saliva.

The construction of low-fouling biosensors for assaying biomarkers in complex biological samples remains a challenge, and the key limitation is the lack of effective anti-fouling materials. Inspired by the biomimetic process of protein phosphorylation, we herein designed a new phosphorylated peptide modified with the dihydrogen phosphate (-PO4H2) group, which significantly increased the hydrophilicity and anti-fouling capability of the peptide when compared with natural and normal peptides. Molecular simulation (MS) illustrated that, compared with the -COOH and -NH2 groups, the -PO4H2 group formed the most numbers of hydrogen bonds and stronger hydrogen bonds with water molecules. As a result, the PO4H2-oligopeptide was proved by MS to be able to attract the greatest number of water molecules, so as to form a compact layer of H2O to resist further adsorption of nonspecific biomolecules. The modification of electrodes with the designed PO4H2-oligopeptides, in addition to the adoption of neutral peptide nucleic acids (PNAs) as the sensing probes, ensured the fabrication of anti-fouling electrochemical biosensors capable of detecting nucleic acids in complex saliva. The constructed anti-fouling biosensor was able to detect the nucleic acid of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in undiluted saliva, with a wide linear response range (0.01 pM-0.01 µM) and a low limit of detection (LOD) of 3.4 fM (S/N = 3). The phosphorylation of oligopeptides offers an effective strategy to designing ultra-hydrophilic peptides suitable for the construction of promising anti-biofouling biosensors and bioelectronics.

Atomistic Insights into the Effect of Functional Groups on the Adsorption of Water by Activated Carbon for Heat Energy Storage.

Adsorption heat storage holds great promise for solar energy applications. The development of new adsorbent materials is currently the research focus in this area. The present work designs several activated carbon models with different functional groups, including -OH, -NH2, -COOH, and -SO3H, and explores the influence of functional groups' categories and numbers on the water adsorption capacity of the activated carbon using the GCMC method. The adsorption mechanism between functional groups and water molecules is analyzed using density functional theory. The results show that the functional groups could significantly improve the water adsorption capacity of activated carbon due to the hydrogen bond between functional groups and water molecules. In the scope of this paper, under low pressure, the activated carbon with -SO3H exhibits the best adsorption capacity, followed by the activated carbon with -COOH. Under low and medium pressure, increasing the number of -SO3H functional groups could increase the water adsorption capacity; however, when the pressure is high, increasing the functional group numbers might decrease the water adsorption capacity. As the temperature increases, the water adsorption capacity of activated carbons decreases, and the activated carbon with -SO3H is proven to have excellent application prospects in heat energy storage.

Intrathecal methotrexate in combination with systemic chemotherapy in glioblastoma patients with leptomeningeal dissemination: A retrospective analysis.

BACKGROUND: Glioblastoma (GBM) is one of the most common and aggressive primary malignant brain tumors with severe symptoms and a poor prognosis. Leptomeningeal dissemination (LMD) is a serious complication of GBM that often results in dire outcomes. There is currently no effective treatment. AIM: To estimate the clinical outcomes of combination therapy in GBM patients with LMD. METHODS: A retrospective analysis was conducted using data collected from GBM patients diagnosed with LMD from January 2012 to December 2019 at our institution. All these patients had received at least one cycle of a combination therapy consisting of intrathecal methotrexate (MTX) and systemic chemotherapy. Clinical and pathological data were analyzed to explore the outcome of GBM patients with LMD and to determine the most effective treatment. RESULTS: Twenty-six patients were enrolled in this study. The median time from GBM diagnosis to LMD development was 9.3 mo (range: 2-59 mo). The median overall survival of LMD patients from diagnosis to after receiving systemic chemotherapy in combination with intrathecal MTX was 10.5 mo (range: 2-59 mo). In the Cox univariate analysis, gross resection of tumor (P = 0.022), Karnofsky performance status (KPS) > 60 (P = 0.002), and Ommaya reservoir implant (P < 0.001) were correlated with survival. Multivariate analysis showed that KPS > 60 (P = 0.037) and Ommaya reservoir implant (P = 0.014) were positive factors correlated with survival. Myelotoxicity and gastrointestinal reactions were the common toxicities of this combination therapy. According to Common Terminology Criteria of Adverse Events 4.03, most of the patients presented with toxicity less than grade 3. CONCLUSION: Intrathecal MTX administration combined with systemic chemotherapy is a potentially effective treatment for patients with GBM and LMD, with mild treatment-related side effects.

Gridding Microsurgical Anatomy of Far Lateral Approach in the Three-Dimensional Model.

OBJECTIVE: The far lateral craniotomy involves osteotomy of various portions of occipital condyle. Intracranial operation exposing clivus encounters complicated neurovascular anatomy. The aim of the present study was to make refinement for the anatomy of far lateral approach by gridding route in the 3-dimensional model. METHODS: Computed tomography and magnetic resonance imaging data were used to construct 3-dimensional model containing osseous and neurovascular structures of skull base. Then, far lateral approach was simulated by triangular prism and divided into gridding surgical route. The relationship of surgical route and osseous and neurovascular structures was observed. Measurement of volume was performed to evaluate surgical exposure. RESULTS: Observation of 3-dimensional model showed bony drilling of far lateral approach started with the occipital condyle and passed through the lateral edge of foramen magnum. The cerebellum and medulla oblongata were exempted from the surgical route exposing clivus. The anatomy variances of operative space, osseous, and neurovascular structures in the gridding route were displayed clearly and compared objectively. CONCLUSION: The gridding operative spaces for the far lateral approach are useful to disclose the detailed discrepancy in the different surgical region. The volumetric measurement provides quantified information to facilitate a better understanding of the anatomy variance.

Quantification of Surgical Route Parameters for Exposure of the Jugular Foramen Via a Trans-Mastoidal Approach Exposing Jugular Foramen in Three-Dimensional Visualization Model.

OBJECTIVE: Surgical operation within the region of the jugular foramen presents a great challenge. The authors characterized the quantitative impact of surgical window parameters on the exposure of the jugular foramen via a trans-mastoidal approach. METHODS: Computed tomography and magnetic resonance imaging data were used to establish a 3-dimensional model of the jugular foramen region. The mastoidale, posterior edge of the mastoid, and the superior edge of the bony external acoustic meatus were selected as points a, b, and c. The anterior edge of the tuberculum jugulare was selected as point d. The midpoints of line segments ab, ac, and bc were selected as points e, f, and g. Triangle abc was divided into triangles aef, beg, cfg, and efg. Surgical corridors of the triangular pyramid were outlined by connecting the above triangles to point d. Anatomic exposure was evaluated by measuring the area and volume of various structures within each route. Statistical comparisons were performed via analysis of variance. RESULTS: The model allowed for adequate visualization of all structures. The areas of triangles beg and efg were greater than those of triangles aef and cfg (P < 0.05). The volumes of triangular pyramids d-beg and d-cfg were greater than those of triangular pyramids d-aef and d-efg (P = 0.000). Statistically significant differences were also observed for volumes of osseous, venous, and cranial nerve structures in all divided routes (P = 0.000). CONCLUSION: Our results indicate that 3-dimensional modeling may aid in the quantification of surgical exposure and that division of the craniotomy window may allow for more precise operation.

Virtual Reality Model of the Three-Dimensional Anatomy of the Cavernous Sinus Based on a Cadaveric Image and Dissection.

OBJECTIVE: Studying the three-dimensional (3D) anatomy of the cavernous sinus is essential for treating lesions in this region with skull base surgeries. Cadaver dissection is a conventional method that has insurmountable flaws with regard to understanding spatial anatomy. The authors' research aimed to build an image model of the cavernous sinus region in a virtual reality system to precisely, individually and objectively elucidate the complete and local stereo-anatomy. METHODS: Computed tomography and magnetic resonance imaging scans were performed on 5 adult cadaver heads. Latex mixed with contrast agent was injected into the arterial system and then into the venous system. Computed tomography scans were performed again following the 2 injections. Magnetic resonance imaging scans were performed again after the cranial nerves were exposed. Image data were input into a virtual reality system to establish a model of the cavernous sinus. Observation results of the image models were compared with those of the cadaver heads. RESULTS: Visualization of the cavernous sinus region models built using the virtual reality system was good for all the cadavers. High resolutions were achieved for the images of different tissues. The observed results were consistent with those of the cadaver head. The spatial architecture and modality of the cavernous sinus were clearly displayed in the 3D model by rotating the model and conveniently changing its transparency. CONCLUSION: A 3D virtual reality model of the cavernous sinus region is helpful for globally and objectively understanding anatomy. The observation procedure was accurate, convenient, noninvasive, and time and specimen saving.

[Multiple factors related with intracranial hemorrhage of dural arteriovenous fistula: clinical analysis].

OBJECTIVE: To discuss the relevant predicative factors of dural arteriovenous fistula (dAVF) in intracranial hemorrhage. METHODS: A total of 144 consecutive patients with dAVFs were recruited for a retrospective analysis from 1996 to 2006. The relevant factors of gender, age, fistula flow rate, arterial supply, lesion and venous drainage pattern were analyzed to evaluate the outcome of intracranial hemorrhage. RESULTS: Univariate analysis showed that gender, lesion and venous drainage pattern were statistical significant for intracranial hemorrhage of DAVF (P < 0.05). However, only venous drainage pattern was significant in the predication of intracranial hemorrhage (P < 0.05). CONCLUSION: Only venous drainage pattern is significant in the predication of dural arteriovenous fistulas in intracranial hemorrhage. Both gender and lesion may be confounding factors.