创伤性眶尖综合征的诊断与治疗进展

创伤性眶尖综合征是一种少见的颅脑创伤并发症,其主要特点是同时有眶上裂综合征和视神经损伤的表现。其临床症状多样,一般有眼肌麻痹、上睑下垂、瞳孔散大、视力减退等特点。诊断主要依靠临床表现和颅底CT三维重建等影像学检查。创伤性眶尖综合征目前有激素治疗和手术减压治疗等。基因治疗、神经干细胞移植在基础研究中取得了众多成果,但在临床应用上还有限制。手术减压目前认为是有效的,手术方式包括开颅手术和内镜手术,经鼻内镜手术减压具有微创、并发症少等优势。最佳的临床决策和手术治疗尚有待于多中心临床研究的开展和循证医学的支持。     

Extended structures sustained by hydrogen bonding and π-π interactions: Synthesis and characterization of Cd(II) complexes with bis(benzimidazolyl) ligands

Two new Cd(II) complexes, {[Cd(C4BIm)Cl₂] · DMF}_n (1) and [Cd(HC4BIm)Cl₃] · 3H₂O (2) (C4BIm = 1,4-bis(benzimidazolyl)butane and HC4BIm = mono-protonated 1,4-bis(benzimidazolyl)butane), have been prepared and characterized spectroscopically and crystallographically. In both complexes, the Cd(II) atom exhibits distorted tetrahedral coordination geometry with CdN₂Cl₂ and CdNCl₃ in 1 and 2, respectively. Complex 1 adopts a racemic structure built up from P- and M-helical [Cd(C4BIm)Cl₂]_n chains, which are alternately linked into two-dimensional network by N-H?Cl hydrogen bonds and further stabilized by the intermolecular π?π stacking. In complexes 2, the HC4BIm is monodentate, coordinating to Cd(II) ion via the unprotonated benzimidazolyl nitrogen donor to form mononuclear [Cd(HC4BIm)Cl₃]. The mononuclear units are linked by N-H?Cl hydrogen bonds to form one-dimensional planar belts, which interact via intermolecular π?π stacking to result in three-dimensional framework.     

In vivo and in vitro bone strain in the owl monkey circumorbital region and the function of the postorbital septum

Anthropoids and tarsiers are the only vertebrates possessing a postorbital septum. This septum, formed by the frontal, alisphenoid, and zygomatic bones, separates the orbital contents from the temporal muscles. Three hypotheses suggest that the postorbital septum evolved to resist stresses acting on the skull during mastication or incision. The facial-torsion hypothesis posits that the septum resists twisting of the face about a rostrocaudal axis during unilateral mastication; the transverse-bending hypothesis argues that the septum resists caudally directed forces acting at the lateral orbital margin during mastication or incision; and the tension hypothesis suggests that the septum resists ventrally directed components of masseter muscle force during mastication and incision. This study evaluates these hypotheses using in vitro and in vivo bone strain data recorded from the circumorbital region of owl monkeys. Incisor loading of an owl monkey skull in vitro bends the face upward in the sagittal plane, compressing the interorbital region rostrocaudally and “buckling” the lateral orbital walls. Unilateral loading of the toothrow in vitro also bends the face in the sagittal plane, compressing the interorbital region rostrocaudally and buckling the working side lateral orbital wall. When the lateral orbital wall is partially cut, so as to reduce the width of its attachment to the braincase, the following changes in circumorbital bone strain patterns occur. During loading of the incisors, lower bone strain magnitudes are recorded in the interorbital region and lateral orbital walls. In contrast, during unilateral loading of the P³, higher bone strain magnitudes are observed in the interorbital region, and generally lower bone strain magnitudes are observed in the lateral orbital walls. During unilateral loading of the M², higher bone strain magnitudes are observed in both the interorbital region and in the lateral orbital wall ipsilateral to the loaded molar. Comparisons of the in vitro results with data gathered in vivo suggest that, during incision and unilateral mastication, the face is subjected to upward bending in the sagittal plane resulting in rostrocaudal compression of the interorbital region. Modeling the lateral orbital walls as curved plates suggests that during mastication the working side wall is buckled due to the dorsally directed component of the maxillary force which causes upward bending of the face in the sagittal plane. The balancing side lateral orbital wall may also be buckled due to upward bending of the face in the sagittal plane as well as being twisted by the caudoventrally directed components of the superficial masseter muscle force. The in vivo data do not exclude the possibility that the postorbital septum functions to improve the structural integrity of the postorbital bar during mastication. However, there is no reason to believe that a more robust postorbital bar could not also perform this function. Hypotheses stating that the postorbital septum originally evolved to reinforce the skull against routine masticatory loads must explain why, rather than evolving a postorbital septum, the stem anthropoids did not simply enlarge their postorbital bars. © 1996 Wiley-Liss, Inc.     

Snapping shrimp have helmets that protect their brains by dampening shock waves

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Thyroid-Associated Ophthalmopathy: Preliminary Study Using T2 Mapping to Characterize Intraorbital Optic Nerve Changes Before Dysthyroid Optic Neuropathy

ObjectiveTo evaluate the performance of T2 mapping in detecting intraorbital optic nerve (ON) changes in patients with thyroid-associated ophthalmopathy (TAO) before the onset of dysthyroid optic neuropathy (DON).MethodsThirty-five patients with TAO and without DON (21 active, 14 inactive) and 21 healthy controls (HCs) were enrolled. Magnetic resonance imaging-derived parameters of T2 relaxation time (T2RT) at the intraorbital ON, extraocular muscle (EOM), orbital fat, exophthalmos, summed thickness of EOMs, orbital fat thickness, and clinical variables were compared. Correlations between T2RT at the ON and other variables were assessed.ResultsPatients with TAO showed significantly higher T2RTs at the intraorbital ON than HCs (P < .001). Patients with active TAO had significantly higher T2RTs than those with inactive TAO and HCs (P < .001). Differences between patients with inactive TAO and HCs were insignificant (P > .05/3). T2RT at the intraorbital ON was positively correlated with clinical activity score, modified NOSPECS score, T2RT at EOM, exophthalmos, and summed thickness of EOMs in the TAO group (P ≤ .003) and negatively correlated with visual acuity (P = .033) and visual field indices (P = .030) in patients with active TAO. A T2RT cutoff of 82.9 ms for the intraorbital ON distinguished active TAO and healthy eyes optimally (area under the curve, 0.800; sensitivity, 85.7%; specificity, 64.3%).ConclusionT2RT detects disturbance in the intraorbital ON in patients with TAO, especially active TAO, before DON develops. T2 mapping has a potential for noninvasive evaluation of ON changes in patients with TAO.     

Metabolism and relative carcinogenic potency of chloroethylenes: A quantum chemical structure-activity study

Properties of six chloroethylenes which could serve as indicators of their relative metabolic behavior and carcinogenic activity have been calculated using Modified Neglect of Diatomic Overlap (MNDO), a semiempirical, all valence electron, molecular orbital method. Possible pathways of transformation of parent compounds to acylchlorides, chloroaldehydes and epoxides — their putative ultimate carcinogens — were considered, and heats of formation and relative stabilities of intermediates were calculated. Our results indicate that carbonyl compounds could be formed with and without the intermediacy of epoxides, suggesting the possibility of more than one pathway in activation of parent compounds. Electronic properties of carbonyl products and epoxide carbocations, putative ultimate carcinogens which could serve as indicators of their relative electrophilicities, were also calculated. The results obtained indicated that the relative extent of metabolism to carbonyl products, rather than their electrophilicity, is a determinant of the relative carcinogenic activity of the parent compound. Of the various thermodynamic criteria investigated, four were found to be indicators of both relative metabolic behavior and carcinogenic activity.