Designing an anatomical contour titanium 3D-printed oblique lumbar interbody fusion cage with porous structure and embedded fixation screws for patients with osteoporosis.

This study aimed to design an anatomical contour metal three-dimensional (3D)-printed oblique lateral lumbar interbody fusion (OLIF) cage with porous (lattices) structure and embedded screw fixation to enhance bone ingrowth to reduce the risk of cage subsidence and avoid the stress-shielding effect. Finite element (FE) analysis and weight topology optimization (WTO) were used to optimize the structural design of the OLIF cage based on the anatomical contour morphology of patients with osteoporosis. Two oblique embedded fixation screws and lattice design with 65% porosity and average pore size of 750 µm were equipped with the cage structure. The cage was fabricated via metal 3D printing, and static/dynamic compression and compressive-shear tests were performed in accordance with the ASTM F2077-14 standard to evaluate its mechanical resistance. On FE analysis, the OLIF cage with embedded screw model had the most stability, lowest stress values on the endplate, and uniform stress distribution versus standalone cage and fixed with lateral plate under extension, lateral flexion, and rotation. The fatigue test showed that the stiffnesses/endurance limits (pass 5 million dynamic test) were 16,658 N/mm/6000 N for axial load and 19,643 N/mm/2700 N for compression shear. In conclusion, an OLIF cage with embedded fixation screws can be designed by integrating FE and WTO analysis based on the statistical results of endplate morphology. This improves the stability of the OLIF cage to decrease endplate destruction. The complex contour and lattice design of the OLIF cage need to be manufactured via metal 3D printing; the dynamic axial compression and compressive-shear strengths are greater than that of the U.S. Food and Drug Administration (FDA) standard.

Inhibition of nitric oxide production enhances the activity of facial nerve tubulin polymerization and the ability of tau to promote microtubule assembly after neurorrhaphy.

We previously reported that inhibition of nitric oxide (NO) production promotes rat reconnected facial nerve regeneration. However, the underlying mechanism is obscure. Microtubule assembly is known to be essential to axon regeneration; nevertheless, tubulins and microtubule-associated proteins (MAPs) have been demonstrated as targets for NO and peroxynitrite. Thus, we hypothesized that NO and/or peroxynitrite may affect facial nerve regeneration via influencing on microtubule assembly. First, tubulins and tau (a MAP) were extracted from facial nerves of normal rats, treated with NO donor or peroxynitrite, and processed for microtubule assembly assay. We found that peroxynitrite, DEA NONOate, and Angeli's salt reduced the tubulin polymerization activity to a greater extent than GSNO, SIN-1, and SNAP. Additionally, SIN-1, peroxynitrite, and Angeli's salt impaired the ability of tau to promote microtubule assembly. Next, nitrosative stress biomarkers 3-nitrotyrosine (3-NT) and S-nitrosylated cysteine (SNO-Cys) were immunolabeled in facial nerves. Both biomarkers were highly upregulated in proximal and distal stumps of reconnected facial nerves at 3 days and 1 week after neurorrhaphy. Notably, the expression of 3-NT was greatly reduced at 2 weeks, whereas that of SNO-Cys was maintained. Conversely, inhibition of NO production with L-NAME prevented the upregulation of SNO-Cys. Further, we used tubulins and tau extracted from facial nerves of sham-operated, nerve suture + vehicle treatment, and nerve suture + L-NAME treatment rats to perform microtubule assembly assay. We found that L-NAME treatment enhanced polymerization activity of tubulins and ability of tau to promote microtubule assembly. It is noteworthy that α-tubulin plays a more important role than ß-tubulin since the activity of microtubule assembly using α-tubulin extracted from L-NAME-treated rats was greatly elevated, whereas that using ß-tubulin extracted from L-NAME-treated rats was not. Overall, our findings support that inhibition of NO production reduces nitrosative stress, and may thus facilitate microtubule assembly and facial nerve regeneration.

Removal of a compressive mass causes a transient disruption of blood-brain barrier but a long-term recovery of spiny stellate neurons in the rat somatosensory cortex.

BACKGROUND: In the cranial cavity, a space-occupying mass such as epidural hematoma usually leads to compression of brain. Removal of a large compressive mass under the cranial vault is critical to the patients. OBJECTIVE: The purpose of this study was to examine whether and to what extent epidural decompression of the rat primary somatosensory cortex affects the underlying microvessels, spiny stellate neurons and their afferent fibers. METHODS: Rats received epidural decompression with preceding 1-week compression by implantation of a bead. The thickness of cortex was measured using brain coronal sections. The permeability of blood-brain barrier (BBB) was assessed by Evans Blue and immunoglobulin G extravasation. The dendrites and dendritic spines of the spiny stellate neurons were revealed by Golgi-Cox staining and analyzed. In addition, the thalamocortical afferent (TCA) fibers in the cortex were illustrated using anterograde tracing and examined. RESULTS: The cortex gradually regained its thickness over time and became comparable to the sham group at 3 days after decompression. Although the diameter of cortical microvessels were unaltered, a transient disruption of the BBB was observed at 6 hours and 1 day after decompression. Nevertheless, no brain edema was detected. In contrast, the dendrites and dendritic spines of the spiny stellate neurons and the TCA fibers were markedly restored from 2 weeks to 3 months after decompression. CONCLUSIONS: Epidural decompression caused a breakdown of the BBB, which was early-occurring and short-lasting. In contrast, epidural decompression facilitated a late-onset and prolonged recovery of the spiny stellate neurons and their afferent fibers.

Characteristics of the accessory tendon of the extensor hallucis longus muscle: a Taiwanese study.

PURPOSE: The main tendon of the extensor hallucis longus (EHL) muscle attaches to the dorsal aspect of the distal phalanx of the great toe. One or multiple accessory tendons of the EHL have been reported in several ethnic/regional groups, except Taiwan. This study aimed to investigate the incidence, length, and insertion of the accessory tendon of the EHL in Taiwanese people. METHODS: Anatomical dissection was performed on 48 feet of 24 formalin-embalmed cadavers. The occurrence and morphological characteristics of the accessory tendon of the EHL were recorded and analyzed. RESULTS: The accessory tendon of the EHL was found in 97.92% (47/48) of the legs that were dissected. In one male cadaver, an independent muscle belly was identified in each leg, whereas all the other accessory tendons originated from the main tendon of the EHL. In this study, the insertion of the accessory tendon were classified into four patterns. The most common insertion sites were the first metatarsophalangeal (MTP) joint capsule and proximal phalanx of the great toe. The length of the accessory tendons did not correlate with age or with sex when the two tendons with independent muscle belly were excluded. CONCLUSIONS: The accessory tendon of the EHL appears to be a regular feature in Taiwanese people. Most accessory tendons of the EHL (85.7%) attached on the first MTP joint capsule may play a role in the prevention of capsular impingement during great toe extension.

Effects of epidural compression on stellate neurons and thalamocortical afferent fibers in the rat primary somatosensory cortex.

A number of neurological disorders such as epidural hematoma can cause compression of cerebral cortex. We here tested the hypothesis that sustained compression of primary somatosensory cortex may affect stellate neurons and thalamocortical afferent (TCA) fibers. A rat model with barrel cortex subjected to bead epidural compression was used. Golgi-Cox staining analyses showed the shrinkage of dendritic arbors and the stripping of dendritic spines of stellate neurons for at least 3 months post-lesion. Anterograde tracing analyses exhibited a progressive decline of TCA fiber density in barrel field for 6 months post-lesion. Due to the abrupt decrease of TCA fiber density at 3 days after compression, we further used electron microscopy to investigate the ultrastructure of TCA fibers at this time. Some TCA fiber terminal profiles with dissolved or darkened mitochondria and fewer synaptic vesicles were distorted and broken. Furthermore, the disruption of mitochondria and myelin sheath was observed in some myelinated TCA fibers. In addition, expressions of oxidative markers 3-nitrotyrosine and 4-hydroxynonenal were elevated in barrel field post-lesion. Treatment of antioxidant ascorbic acid or apocynin was able to reverse the increase of oxidative stress and the decline of TCA fiber density, rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons post-lesion. Together, these results indicate that sustained epidural compression of primary somatosensory cortex affects the TCA fibers and the dendrites of stellate neurons for a prolonged period. In addition, oxidative stress is responsible for the reduction of TCA fiber density in barrels rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons.

Differential regulation of glial reactions in the central facial tract and the facial nucleus after facial neurorrhaphy.

We previously reported that perineuronal astrocytic and microglial reactions are drastically upregulated in the facial nucleus after facial axotomy at the brain stem surface or the stylomastoid foramen. Furthermore, periaxonal astrocytic and microglial reactions develop retrogradely in the central facial tract which contains proximal facial axons in the brain stem. Because reconnection of interrupted peripheral nerve by microsurgical suture is a common clinical practice, the aim of this study was to investigate the spatiotemporal patterns of glial reactions in the central facial tract and the facial nucleus after facial neurorrhaphy. Here, we show immunofluorescent and immunohistochemical evidence that facial neurorrhaphy at the stylomastoid foramen largely prevented axotomy-induced astrocytic and microglial activation in the central facial tract. In contrast, glial reactions in the facial nucleus were still highly elevated after facial neurorrhaphy. Microglial and astrocytic processes were observed to ensheath the facial motoneurons in the facial nucleus. Nevertheless, the transformation of ramified to amoeboid shape of microglia, occurring at 10 weeks after facial axotomy, was not seen after neurorrhaphy. We further examined the effect of N-nitro-l-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS), on glial reactions after neurorrhaphy. Western blot analyses demonstrate that inhibition of nitric oxide (NO) production significantly reduced microglial but not astrocytic reaction in the facial nucleus after neurorrhaphy. Taken together, these results indicate that in contrast to the intense glial reactions in both the central facial tract and the facial nucleus after facial axotomy, glial reactions are differentially regulated in these two compartments after facial neurorrhaphy. NO is involved in the activation of microglia in the facial nucleus after facial neurorrhaphy.

Aluminum complexes incorporating symmetrical and asymmetrical tridentate pincer type pyrrolyl ligands: synthesis, characterization and reactivity study.

A series of aluminum complexes incorporating substituted symmetrical and asymmetrical tridentate pyrrolyl ligands are synthesized conveniently and the treatment of the derivatives with small organic molecules are analyzed. The reaction of lithiated [C4H2NH(2-CH2NH(t)Bu)(5-CH2NR1R2)], where for 1, R1 = R2 = Me; 2, R1 = H, R2 = (t)Bu, with AlCl3 in diethyl ether affords Al[C4H2N(2-CH2NH(t)Bu)(5-CH2NMe2)]Cl2 (3) and Al[C4H2N(2,5-CH2NH(t)Bu)2]Cl2 (4), respectively, in high yields. Furthermore, subjecting 3 and 4 to reaction with one equiv. of LiNMePh in diethyl ether generates Al[C4H2N(2-CH2NH(t)Bu)(5-CH2NMe2)][NMePh]Cl (5) and Al[C4H2N(2,5-CH2NH(t)Bu)2][NMePh]Cl (6), respectively, while eliminating one equiv. of LiCl. The reaction between compound 4 with two equiv. of LiO-Ph-4-Me in diethyl ether yields the aluminum di-phenoxide compound Al[C4H2N(2,5-CH2NH(t)Bu)2](O-Ph-4-Me)2 (7) whereas the combination of 3 and two equiv. of LiNH(t)Bu, produces Al[C4H2N(2-CH2N(t)Bu)(5-CH2NMe2)](NH(t)Bu)(NH2(t)Bu) (8). Additionally, the mixing of 1 and one equiv. of AlMe3 renders Al[C4H2N(2-CH2NH(t)Bu)(5-CH2NMe2)]Me2 (9). Adding one more equiv. of AlMe3 with 9 affords {Al[C4H2N(2-CH2NH(t)Bu)(5-CH2NMe2)AlMe3]Me2} (10), which can also be obtained by treating 1 with two equiv. of AlMe3 directly. The treatment of 9 with one equiv. of 2,6-dimethylphenol in diethyl ether gives the aluminum alkoxide derivative, Al[C4H2N(2-CH2NH(t)Bu)(5-CH2NMe2)](O-C6H3-2,6-Me2)Me (11). Furthermore, the reaction between 9 and one equiv. of 1-ethyl-1-phenyl ketene, initiates the aluminum dimethyl complex Al{C4H2N[2-CH2CEtPh-C(=O)-NH(t)Bu](5-CH2NMe2)}Me2 (12) with a C-N bond breakage and a C-C bond formation. All the Al-derivatives are characterized by (1)H and (13)C NMR spectroscopy and the molecular structures are determined by single crystal X-ray diffractometry in solid state.

Effects of phorbol myristate acetate and sivelestat on the lung injury caused by fat embolism in isolated lungs.

BACKGROUND: Fat embolism syndrome (FES) associated with acute lung injury (ALI) is a clinical condition following long bone fracture. We have reported 14 victims due to ALI with FES. Our laboratory has developed an animal model that produced fat emboli (FE). The major purpose of this study was to test whether neutrophil activation with phorbol myristate acetate (PMA) and inhibition with sivelestat (SVT) exert protection on the lung. METHODS: The lungs of Sprague-Dawley rats were isolated and perfused. FE was produced by addition of corn oil micelles into the lung perfusate. PMA and SVT were given simultaneously with FE. Parameters such as lung weight/body weight ratio, LW gain, exhaled nitric oxide (NO), protein concentration in bronchoalveolar lavage relating to ALI were measured. The neutrophil elastase (NE), myeloperoxidase, malondialdehyde and phopholipase A2 activity were determined. We also measured the nitrate/nitrite, methyl guanidine (MG), and cytokines. Pulmonary arterial pressure and microvascular permeability were assessed. Lung pathology was examined and scored. The inducible and endothelial NO synthase (iNOS and eNOS) were detected. RESULTS: FE caused ALI and increased biochemical factors. The challenge also resulted in pulmonary hypertension and increased microvascular permeability. The NE appeared to be the first to reach its peak at 1 hr, followed by other factors. Coadministration with PMA exacerbated the FE-induced changes, while SVT attenuated the effects of FE. CONCLUSIONS: The FE-induced lung changes were enhanced by PMA, while SVT had the opposite effect. Sivelestat, a neutrophil inhibitor may be a therapeutic choice for patients with acute respiratory distress syndrome (ARDS) following fat embolism.

Dichlorido{N'-[(pyridin-2-yl)methyl-idene-κN]acetohydrazide-κN',O}copper(II).

In the title compound, [CuCl(2)(C(8)H(9)N(3)O)], the Cu(II) atom has a distorted square-pyramidal CuCl(2)N(2)O coordination geometry. The tridentate acetohydrazide ligand occupies three basal positions, the fourth basal position being defined by a chloride anion at a distance of 2.2116 (6) Å. The second chloride anion is in the apical position and forms a longer Cu-Cl distance of 2.4655 (7) Å. Inter-molecular N-H⋯Cl hydrogen bonds are present in the crystal, leading to the formation of chains along [10[Formula: see text]].

Ascorbic acid prevents blood-brain barrier disruption and sensory deficit caused by sustained compression of primary somatosensory cortex.

Transient compression of rat somatosensory cortex has been reported to affect cerebral microvasculature and sensory function simultaneously. However, the effects of long-term cortical compression remain unknown. Here, we investigated whether and to what extent sustained but moderate epidural compression of rat somatosensory cortex impairs somatic sensation and/or cortical microvasculature. Electrophysiological and behavioral tests revealed that sustained compression caused only short-term sensory deficit, particularly at 1 day after injury. Although the diameter of cortical microvessels was coincidentally reduced, no ischemic insult was observed. By measuring Evans Blue and immunoglobulin G extravasation, the blood-brain barrier (BBB) permeability was found to dramatically increase during 1 to 3 days, but this did not lead to brain edema. Furthermore, immunoblotting showed that the BBB component proteins occludin, claudin-5, type IV collagen, and glial fibrillary acidic protein were markedly upregulated in the injured cortex during 1 to 2 weeks when BBB regained integrity. Conversely, treatment of ascorbic acid prevented compression-induced BBB disruption and sensory impairment. Together, these data suggest that sustained compression of the somatosensory cortex compromises BBB integrity and somatic sensation only in the early period. Ascorbic acid may be used therapeutically to modulate cortical compression and/or BBB dysfunction.

Inhibition of nitric oxide synthase promotes facial axonal regeneration following neurorrhaphy.

Reconnection of interrupted peripheral nerve by microsurgical suture is a common clinical practice. However, the extent to which peripheral neurorrhaphy improves nerve regeneration and functional recovery remains unsatisfactory. Here, we used anatomical and electrophysiological techniques to investigate the temporal correlation between the expressions of oxidative stress-related biomarkers such as neuronal nitric oxide synthase (nNOS) and the facial axonal regeneration after an immediate facial nerve repair in adult rats since peripheral nerve lesion is well known to induce a dramatic increase of NOS expression in the affected neuronal cell bodies. We found that compared to nerve cut without suture, facial nerve repair not only caused the facial axonal regeneration but also consistently prevented the fluctuations of expressions of oxidative stress-related biomarkers in 10 weeks postlesion. To further elucidate the role of nitric oxide (NO) in the axonal degeneration/regeneration, four different NOS inhibitors were applied to additional rats after facial nerve cut or repair. Both of facial nerve cut+NOS inhibition and facial nerve repair+NOS inhibition were seen to prevent the alterations of expressions of the biomarkers, no matter which NOS inhibitor was used. Moreover, we found that facial nerve repair+NOS inhibition promoted earlier and better axonal regeneration than facial nerve repair, demonstrated by labeling of neuromuscular junctions, retrograde tracing, and electromyography. These results provide direct evidence that peripheral nerve suture and/or treatment of NOS inhibitors can maintain the homeostasis of oxidative stress-related biomarkers, especially nNOS in neuronal cell bodies. These actions may thus facilitate the axonal regeneration.

Proximity of lesioning determines response of facial motoneurons to peripheral axotomy.

We recently found that rubrospinal (RS) neurons, which typify central neurons projecting within the central nervous system (CNS), exhibited different neuronal and glial reactions to axotomy at proximal as opposed to distal sites. To determine whether distance also determines the reaction to axonal injury of central neurons projecting to the periphery, we studied the temporal expression of four free-radical-related enzymes as well as the severity of cell loss, perineuronal astrocytic and microglial reactions, and degeneration of the proximal central axons of facial motoneurons after axotomies performed at various sites on the brainstem surface and in the stylomastoid foramen, respectively. Distal lesions resulted in upregulation of these neurons' expression of nitric oxide synthase (NOS) and persistent downregulation of their expression of the NOS-activating enzyme calcineurin. It also led to transient upregulation of their expression of manganese-dependent superoxide dismutase (Mn-SOD), and resulted in a mild neuronal loss. Proximal axotomy led to an upregulation of NOS but a transient downregulation in the expression of calcineurin and Mn-SOD at 4 weeks after injury. This was accompanied by severe cell loss and swelling of mitochondria at 2-4 weeks postinjury. However, neither proximal nor distal axonal lesioning led to nuclear fragmentation or TUNEL staining of neurons. Proximal as opposed to distal axotomy produced an earlier transformation of glial morphology, including the hypertrophy of astrocytic processes and metamorphosis of ramified microglia to amoeboid cells. We unexpectedly found that unlike RS neurons, whose central axons degenerated slowly and in an anterograde manner only after the severe cell loss induced by proximal axotomy, the central axons of facial motoneurons degenerated rapidly and in a retrograde manner independently of the severity of loss of these neurons after axotomy. However, degeneration began sooner after proximal than after distal axotomy. Since the central axons of both rubrospinal neurons and facial motoneurons lie within the CNS, the differences in whether and how they degenerated after axotomy suggests that central neurons that project within and outside the CNS are inherently different. The significance of these and also the free radical environment regulation differences between these two types of neurons following close and distant axotomies remains to be explored.

Close axonal injury of rubrospinal neurons induced transient perineuronal astrocytic and microglial reaction that coincided with their massive degeneration.

To learn more about the pathophysiology of axonal injury and the significance of axon collaterals on the survival of axotomized cord-projection central neurons, we studied the survival rate, surrounding astrocytic and microglial reactions, and bouton coverage on rat rubrospinal cell bodies following their axonal lesion at the brain stem and upper cervical level. The brain stem lesion disconnected most rubrospinal neurons from all their targets, while the upper cervical lesion spared their supraspinal collaterals. Much higher cell loss accompanied by robust astrocytic and microglial reaction was found following brain stem than upper cervical lesion starting 4 days postaxotomy. The reaction of astrocytes had subsided while microglial reaction remained relatively robust by 10 weeks postaxotomy when the cell loss had slowed down. Ultrastructural observation revealed that reactive astrocytes covered 40%, an increase from the 20% of control, of brain stem-axotomized rubrospinal cell body surface at 4 days and 2 weeks and returned to normal levels by 10 weeks postlesion. An increase of apposition by axons and dendrites and a moderate decrease of round and flattened vesicle-containing bouton contacts at 4 days and 2 weeks and returning to normal levels at 10 weeks postaxotomy accompanied this. It appears that although axotomy induced robust astrocytic reaction around cord-projection central neurons, this, unlike their periphery-projection counterparts, failed to effectively strip their somatic synapses. In effect, this might in part determine neuronal fate following axonal injury.