58 research outputs found
Flavor structure in D-brane models: Majorana neutrino masses
We study the flavor structure in intersecting D-brane models. We study
anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino
masses, which can be generated by D-brane instanton effects. It is found that a
certain pattern of mass matrix is obtained and the cyclic permutation symmetry
remains unbroken. As a result, trimaximal mixing matrix can be realized if
Dirac neutrino mass and charged lepton mass matrices are diagonal.Comment: 17 pages, 1 figur
Standard Model-like D-brane models and gauge couplings
We systematically search intersecting D-brane models, which just realize the
Standard Model chiral matter contents and gauge symmetry. We construct new
classes of non-supersymmetric Standard Model-like models. We also study gauge
coupling constants of these models. The tree level gauge coupling is a function
of compactification moduli, string scale, string coupling and winding number of
D-branes. By tuning them, we examine whether the models can explain the
experimental values of gauge couplings. As a result, we find that the string
scale should be greater than GeV if the compactification scale and
the string scale are the same order.Comment: 25 pgaes, 12 figures: v2 appendix adde
Hemodynamic impact of ephedrine on hypotension during general anesthesia : a prospective cohort study on middle-aged and older patients
Background
Ephedrine is a mixed α- and β-agonist vasopressor that is frequently used for the correction of hypotension during general anesthesia. β-responsiveness has been shown to decrease with age; therefore, this study aimed to determine whether aging would reduce the pressor effect of ephedrine on hypotension during general anesthesia.
Methods
Seventy-five patients aged ≥ 45 years were included in this study, with 25 patients allocated to each of the three age groups: 45–64 years, 65–74 years, and ≥ 75 years. All patients received propofol, remifentanil, and rocuronium for the induction of general anesthesia, followed by desflurane and remifentanil. Cardiac output (CO) was estimated using esCCO technology. Ephedrine (0.1 mg/kg) was administered for the correction of hypotension. The primary and secondary outcome measures were changes in the mean arterial pressure (MAP) and CO, respectively, at 5 min after the administration of ephedrine.
Results
The administration of ephedrine significantly increased MAP (p < 0.001, mean difference: 8.34 [95% confidence interval (CI), 5.95–10.75] mmHg) and CO (p < 0.001, mean difference: 7.43 [95% CI, 5.20–9.65] %) across all groups. However, analysis of variance revealed that the degree of elevation of MAP (F [2, 72] = 0.546, p = 0.581, η2 = 0.015 [95% CI, 0.000–0.089]) and CO (F [2, 72] = 2.023, p = 0.140, η2 = 0.053 [95% CI, 0.000–0.162]) did not differ significantly among the groups. Similarly, Spearman’s rank correlation and multiple regression analysis revealed no significant relation between age and the changes in MAP or CO after the administration of ephedrine.
Conclusion
The administration of ephedrine significantly increased MAP and CO; however, no significant correlation with age was observed in patients aged > 45 years. These findings suggest that ephedrine is effective for the correction of hypotension during general anesthesia, even in elderly patients
Anesthetic management of a patient with methylmalonic acidemia : a case report
Background: Methylmalonic acidemia (MMA) is a metabolic disorder of organic acids and is characterized by the accumulation of methylmalonic acids.
Case presentation: The patient was a 19-year-old female diagnosed with severe MMA at 3 days of age, who was scheduled for renal replacement therapy. Preoperatively, there was no evidence of metabolic acidosis or electrolyte abnormalities. Glucose was administered preoperatively following a 6-h fast. Anesthesia was administered using thiamylal, remifentanil, rocuronium, and sevoflurane. After tracheal intubation, the patient underwent an ultrasoundguided bilateral rectus sheath block with ropivacaine. A drop in blood sugar level was treated with 5% glucose. Extubation was performed after intravenous administration of sugammadex.
Conclusions: We report the anesthetic management of a patient with MMA using a combination of general anesthesia and rectus sheath block
General anesthesia of a Japanese infant with Barber-Say syndrome : a case report
Background: Barber-Say syndrome (BSS) is a very rare congenital disorder characterized by macrostomia, cutis laxa, and other features. We report our experience of performing general anesthesia on a Japanese child with BSS.
Case presentation: A bilateral repair of the corners of the mouth under general anesthesia was planned for an 18-month-old male with macrostomia; the child was 75 cm in height and weighed 9.9 kg. As insertion of the peripheral intravenous catheter was difficult, it was inserted before the surgery by a pediatrician. The patient wore a mask and was ventilated manually after loss of consciousness with intravenous anesthesia. A mask for adults provided a superior fit and was effective in preventing air leakage from the corners of the mouth. After rocuronium was administered, the larynx was spread with a Macintosh laryngoscope. There was no laryngeal anatomical abnormality, and tracheal intubation was readily possible. The operation was completed without incident. Stiffening of both arms occurred for several seconds one hour after the operation ended, but the patient did not develop other complications.
Conclusions: Mask ventilation and the insertion of an intravenous catheter may be difficult in the general anesthesia of patients with BSS, and anesthetic management requires caution
MSKdeX: Musculoskeletal (MSK) decomposition from an X-ray image for fine-grained estimation of lean muscle mass and muscle volume
Musculoskeletal diseases such as sarcopenia and osteoporosis are major
obstacles to health during aging. Although dual-energy X-ray absorptiometry
(DXA) and computed tomography (CT) can be used to evaluate musculoskeletal
conditions, frequent monitoring is difficult due to the cost and accessibility
(as well as high radiation exposure in the case of CT). We propose a method
(named MSKdeX) to estimate fine-grained muscle properties from a plain X-ray
image, a low-cost, low-radiation, and highly accessible imaging modality,
through musculoskeletal decomposition leveraging fine-grained segmentation in
CT. We train a multi-channel quantitative image translation model to decompose
an X-ray image into projections of CT of individual muscles to infer the lean
muscle mass and muscle volume. We propose the object-wise intensity-sum loss, a
simple yet surprisingly effective metric invariant to muscle deformation and
projection direction, utilizing information in CT and X-ray images collected
from the same patient. While our method is basically an unpaired image-to-image
translation, we also exploit the nature of the bone's rigidity, which provides
the paired data through 2D-3D rigid registration, adding strong pixel-wise
supervision in unpaired training. Through the evaluation using a 539-patient
dataset, we showed that the proposed method significantly outperformed
conventional methods. The average Pearson correlation coefficient between the
predicted and CT-derived ground truth metrics was increased from 0.460 to
0.863. We believe our method opened up a new musculoskeletal diagnosis method
and has the potential to be extended to broader applications in multi-channel
quantitative image translation tasks. Our source code will be released soon.Comment: MICCAI 2023 early acceptance (12 pages and 6 figures
Porphyromonas gingivalis Outer Membrane Vesicles Stimulate Gingival Epithelial Cells to Induce Pro-Inflammatory Cytokines via the MAPK and STING Pathways
Porphyromonas gingivalis (Pg) is a keystone pathogen associated with chronic periodontitis and produces outer membrane vesicles (OMVs) that contain lipopolysaccharide (LPS), gingipains, and pathogen-derived DNA and RNA. Pg-OMVs are involved in the pathogenesis of periodontitis. Pg-OMV-activated pathways that induce the production of the pro-inflammatory cytokines, interleukin (IL)-6, and IL-8 in the human gingival epithelial cell line, OBA-9, were investigated. The role of mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB in levels of Pg-OMV-induced pro-inflammatory cytokines was investigated using Western blot analysis and specific pathway inhibitors. Pg-OMVs induced IL-6 and IL-8 production via the extracellular signal-regulated kinase (Erk) 1/2, c-Jun N-terminal kinase (JNK), p38 MAPK, and NF-κB signaling pathways in OBA-9 cells. In addition, the stimulator of interferon genes (STING), an essential innate immune signaling molecule, was triggered by a cytosolic pathogen DNA. Pg-OMV-induced IL-6 and IL-8 mRNA expression and production were significantly suppressed by STING-specific small interfering RNA. Taken together, these results demonstrated that Pg-OMV-activated Erk1/2, JNK, p38 MAPK, STING, and NF-κB signaling pathways resulting in increased IL-6 and IL-8 expression in human gingival epithelial cells. These results suggest that Pg-OMVs may play important roles in periodontitis exacerbation by stimulating various pathways
PONV after intraarticular anesthesia
Study Objective : the incidence of postoperative nausea and vomiting (PONV) following single-injection intraarticular anesthesia was compared to that following continuous epidural anesthesia. Design : Prospective, double-blind, randomized study. Setting : University-affiliated teaching hospital. Patients : Forty-eight patients finally participated in this study, and each group contained twenty-four patients. Interventions : Patients scheduled to undergo lower limb surgery under general anesthesia were randomly allocated into two groups, to receive either single-injection intraarticular or continuous epidural anesthesia for postoperative analgesia. Measurements : The incidence and severity of PONV, complete response rates (i.e., no vomiting or rescue antiemetic use), and pain scores were recorded 2, 24, and 48 h postoperatively. Main results : No significant differences between groups were observed in the incidence and severity of PONV, rescue antiemetic use, or complete response rate at any of the time points, but only the use of rescue analgesics was significantly less in continuous epidural anesthesia group during the 2-24h postoperative period (P=0.04). Conclusion : While the use of single-injection intraarticular anesthesia following lower limb surgery did not prevent PONV more than continuous epidural anesthesia in this study, the intraarticular technique still provides greater simplicity, safety, and cost-effectiveness
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