Chitosan 3D scaffolds with resolvin D1 for vertebral arthrodesis: a pilot study

PURPOSE

Over the last years, the number of vertebral arthrodesis has been steadily increasing. The use of iliac crest bone autograft remains the "gold standard" for bone graft substitute in these procedures. However, this solution has some side effects, such as the problem of donor site morbidity indicating that there is a real need for adequate alternatives. This pilot study aimed to evaluate the usefulness of chitosan (Ch) porous 3D scaffolds incorporated with resolvin D1 (RvD1) as an alternative implant to iliac bone autograft.

METHODS

We have performed bilateral posterolateral lumbar vertebral arthrodesis in a rat animal model. Three experimental groups were used: (i) non-operated animals; (ii) animals implanted with Ch scaffolds incorporated with RvD1 and (iii) animals implanted with iliac bone autograft.

RESULTS

The collagenous fibrous capsule formed around the Ch scaffolds with RvD1 is less dense when compared with the iliac bone autograft, suggesting an important anti-inflammatory effect of RvD1. Additionally, new bone formation was observed in the Ch scaffolds with RvD1.

CONCLUSION

These results demonstrate the potential of these scaffolds for bone tissue repair applications.

A new suction instrument for spinal surgery

OBJECTIVE

Spinal surgical procedures share the technical difficulty of having to preserve the integrity of the dura mater in a surgical field with different degrees of hemorrhage. This difficulty is particularly evident in the surgery of degenerative diseases.

METHODS

We have developed a new surgical sucker that allows an easy dissection of the dural sac from adjacent structures and improves the overall surgical manipulation during degenerative lumbar spinal procedures. The present technical note describes this newly developed suction device that comprises a slightly oval spatula positioned at an angle of 30° to the bore of the suction tube.

RESULTS AND CONCLUSION

Attending to the combination of a spatula and a suction device, it offers several advantages when compared to the instruments that are currently available. Namely, it facilitates the dissection of the ligamentum flavum from the subjacent dura mater, separating and holding this ligamentum from the dura mater; it also allows a slight retraction of the dural sac without direct suction and a better illumination of the surgical field through light reflected from the spatula.

Occupancy of rotational population in molecular spectra based on nonextensive statistics

The procedure to obtain gas temperature in plasmas is to fit the experimental rotational spectrum to a theoretical one based on the Boltzmann distribution. For many systems a single distribution fails to account for the occupation of the levels. Researchers have improved the fitting by coupling two distributions and obtaining two distinct temperatures. They assigned the lowest temperature to the gas. Here, we show that these systems should be described by Tsallis nonextensive statistics and its unique associated temperature. Experimental and simulated spectra are tested and excellent agreement is obtained.

Lesion development and replication kinetics during early infection in cattle inoculated with Vesicular stomatitis New Jersey virus via scarification and black fly (Simulium vittatum) bite

Vesicular stomatitis viruses are the causative agents of vesicular stomatitis, an economically important contagious disease of livestock that occurs in North, Central, and South America. Little is known regarding the early stages of infection in natural hosts. Twelve adult Holstein steers were inoculated with Vesicular stomatitis New Jersey virus (VSNJV) on the coronary bands (CB) of the feet via scarification (SC) or by VSNJV-infected black fly (Simulium vittatum) bite (FB). Three additional animals were inoculated on the neck skin using FB. Clinical disease and lesion development were assessed daily, and animals were euthanatized from 12 hours post inoculation (HPI) through 120 HPI. The animals inoculated in the neck failed to develop any clinical signs or gross lesions, and VSNJV was detected neither by in situ hybridization (ISH) nor by immunohistochemistry (IHC). Lesions on the CB were more severe in the animals infected by FB than by SC. In both groups, peak VSNJV replication occurred between 24 and 48 HPI in keratinocytes of the CB, as evidenced by ISH and IHC. There was evidence of viral replication limited to the first 24 HPI in the local draining lymph nodes, as seen through ISH. Successful infection via FB required logarithmically less virus than with the SC technique, suggesting that components in black fly saliva may facilitate VSNJV transmission and infection in cattle. The lack of lesion development in the neck with the same method of inoculation used in the CB suggests that specific characteristics of the CB epithelium may facilitate VSNJV infection.

Vascular and apoptotic changes in the placode of myelomeningocele mice during the final stages of in utero development

OBJECT

Myelomeningocele (MMC) is a primary neurulation defect that is associated with devastating neurological disabilities in affected newborns. To better characterize the in utero neurodegenerative process of MMC, the authors investigated the changes in vascular organization, apoptosis, and the presence of inflammatory cells during gestation by using a mutant mouse model of MMC.

METHODS

The curly tail/loop tail (ct/lp) mutant mouse model of MMC was chosen to obtain fetuses at different stages of gestation. Mouse fetuses harboring MMC were harvested by caesarean section at embryonic Days 14.5, 16.5, and 18.5 (complete mouse gestation at 19 days, 6 mice/group); littermate fetuses with the same gestational age but without an MMC were used as controls. Samples of the MMC placode or normal spinal cord were stained for immunocytochemical labeling with caveolin antibody (endothelium marker) and activated caspase-3 antibody (apoptosis marker). Samples were morphometrically analyzed with a computer-assisted image analyzer.

RESULTS

The MMC mice presented with an increase in vascular density from embryonic Days 16.5-18.5 and an enhanced number of apoptotic cells at embryonic Day 18.5, compared with controls. There were scarce signals of an inflammatory reaction in the MMC placode, as a few infiltrating neutrophils were seen only at embryonic Day 18.5.

CONCLUSIONS

Fetal placodes in MMC mice showed evidence of increased vascular density since embryonic Day 16.5 and increased apoptosis at embryonic Day 18.5. These new data support the view that in utero changes of the MMC placode, occurring during the last stages of gestation, contribute to the neuropathological manifestations in full-term newborns with MMC.

Immunocytochemical characterization of astrocytosis along the spinal cord of loop-tail/curly-tail mice with myelomeningocele

BACKGROUND

The neurological deficits of myelomeningocele (MMC) have been attributed both to a primary neurulation defect and to a secondary injury of the placode in the intrauterine environment. Since astrocytes are involved in glial scar formation after spinal cord injury, the characterization of astrocyte density along the spinal cord upstream of the MMC can be used as a surrogate marker of the extension of the injury beyond the MMC.

METHODS

The curly-tail/loop-tail murine model was applied to obtain newborn mice with MMC. The astrocyte density and topography both at the MMC placode level and at the upper segments of the spinal cord was characterized by immunolabeling using the anti-glial fibrillary acidic protein antibody. This was followed by a qualitative evaluation of immunolabeled cells and morphometric analysis of the samples.

RESULTS

The topography of astrocytes in the spinal cord of MMC newborn mice was compared with that of newborn control mice (without spina bifida aperta) (n = 8/group). The anti-glial fibrillary acidic protein immunoreactivity was significantly increased in the MMC samples in comparison with the normal spinal cord, indicating the presence of an astrocytic response. Increased astrocytosis was also observed in the transitional area located above the MMC. The astrocytosis decreased progressively along the MMC spinal cord until matching the pattern of the control spinal cords. This transitional area involved a segment of the spinal cord with a length of 240 microm in the newborn mouse.

CONCLUSIONS

MMC newborn mice show spinal cord injury that is located upstream of the exposed placode and is characterized by proliferation of astrocytes. This finding offers further support for the hypothesis of a tethering mechanism as part of the spinal cord injury observed in MMC newborns.

Orbital (retrobulbar) meningioma in a Simmental cow

A 12-year-old Simmental cow was presented with a moderately firm irregular whitish mass of approximately 5 cm in diameter, occupying the right orbit. Microscopically, a poorly differentiated neoplasm was observed. The immunohistochemical panel included cytokeratins, vimentin, epithelial membrane antigen, Factor VIII, CD34, Mart-1, Melan A, smooth muscle actin, desmin, chromogranin, neuron-specific enolase, S-100 protein, and MIB-1. The neoplasm was negative for all of them, with the exception of vimentin and S-100 protein. Transmission electron microscopy revealed abundant desmosomes. These findings support the diagnosis of orbital (retrobulbar) meningioma.

In utero topographic analysis of astrocytes and neuronal cells in the spinal cord of mutant mice with myelomeningocele

OBJECT

Myelomeningocele (MMC) is the most severe form of spina bifida causing severe neurological deficits. Injury to the placode has been attributed to in utero aggression. In this study, glial and neuronal cell changes in both number and topography in mice with MMC were investigated during gestation.

METHODS

The curly tail/loop-tail mice model of MMC was used, and fetuses were harvested using caesarean surgery at Days 14.5, 16.5, and 18.5 (full gestation at 19 days). Immunohistochemical analyses of the MMC placodes and the normal spinal cords from the control group were performed using anti-glial fibrillary acidic protein (astrocytes) and mouse anti-neuronal nuclear (neurons) antibodies. Light microscopy was used along with computer-assisted morphometric evaluation. Progressive increases in astrocytes in the spinal cord of all mouse fetuses were found between Days 14.5 and 18.5 of gestation. This increase was significantly higher in the placodes of mice with MMC than in those of normal mice, particularly in the posterior region. Neuronal labeling at Day 14.5 of gestation was similar between mice with MMC and control mice. At Day 16.5 of gestation there was a deterioration of neural tissue in MMC fetuses, mainly in the posterior region, progressing until the end of gestation with a marked loss of neurons in the entire MMC placode.

CONCLUSIONS

This study delineated the quantitative changes in astrocytes and neurons associated with MMC development during the late stages of gestation. The detailed topographic analysis of the MMC defines the timing of the intrauterine insult and how the placode lesions progress. This study supports the current concept of placode protection through in utero surgery for fetuses with MMC.

In utero meconium exposure increases spinal cord necrosis in a rat model of myelomeningocele

BACKGROUND/PURPOSE

The rationale for in utero repair of myelomeningocele has been supported experimentally by the observation of preserved neural function after prenatal closure of surgically created defects compared with nonrepaired controls. The mechanism of injury to the exposed neural elements is unknown. Postulated mechanisms include trauma to the herniated neural elements or progressive injury from amniotic fluid exposure as gestation proceeds. A component of amniotic fluid that may contribute to neural injury is meconium. In the current study the effect of human meconium on the exposed spinal cord in a fetal rat model of myelomeningocele was examined.

METHODS

Twenty time-dated pregnant rats underwent laparotomy at 181/2 days of gestation. The exposed uterus was bathed in ritrodrine for tocolysis. The amniotic cavity was opened over the dorsal midline of the fetal rat, and, under a dissecting microscope (x25), a 2- to 3-level laminectomy was performed. Under magnification (x40), the translucent dura was opened using a 25-gauge needle as a knife. Two fetuses per dam were operated on. In the control group, the amniotic fluid was restored with saline solution, whereas in the experimental group a solution of Human meconium diluted (10%) in saline was used to restore the amniotic fluid. Fetuses were harvested by cesarean section at 211/2 days' gestational age. The liveborn pups were then killed and fixed in 10% formaline. Sections 10 micrometer thick were stained with H&E and studied by light microscopy for evidence of spinal cord injury.

RESULTS

Seven of 20 (35%) experimental rat pups and 6 of 20 (30%) control rat pups were liveborn. All liveborn pups had severe paralysis of the hindlimbs and tail, so that functional differences between the 2 groups could not be detected. Histologic examination of 13 spinal cords at the site of surgical exposure showed that necrosis of neural tissue in 5 of 7 meconium-exposed rat pups was increased when compared with that observed in the 6 fetuses exposed to amniotic fluid without meconium. In general, inflammation was greater and repair processes appeared delayed in meconium-exposed rat pups.

CONCLUSIONS

Exposure of the spinal cord of fetal rats to amniotic fluid by surgically created myelomeningocele leads to severe functional impairment. Histologically recognizable necrosis of neural elements was increased in those animals that were exposed to diluted human meconium in the amniotic fluid. The results support the hypothesis that meconium may contribute to the pathophysiology of spinal cord injury observed in myelomeningocele.

[Cochlear otosclerosis]

A rare case of cochlear otosclerosis is described with clinical data, CT and RMN images. The aim of this note is to improve the acknowledgement of in vivo otosclerosis physiopathology.

[Dysembryoplastic neuroepithelial tumors]

INTRODUCTION

The dysembryoplastic neuroepithelial tumors tend to occur in young patients, with partial complex partial seizures which is refractory to medical treatment. These are stable lesions, with defined histological features, specially with clinical data corroboration.

CLINICAL CASES

The clinical, imagiological, operative, and histopathological data of six patients with proved dysembryoplastic neuroepithelial tumors were reviewed. All patients had seizures with age at onset ranged from 7 to 27 years. Five lesions were located in the temporal lobe and one in the parietal lobe. Common features included cortical to subcortical location, low density in CT-scan, very low signal intensity on T1-weighted images and high signal on T2-weighted images. Calcification occurred in two lesions, and three showed contrast enhancement. Complete resection of the tumor was performed in three cases, and subtotal resection in other three cases. Pathological features included oligodendroglial-like cells, glioneural component, and few cases showed dysplastic cortical disorganization. The postoperative period of follow-up ranged from 2 to 18 months. Four patients were seizure free, two of which had subtotal resection of the lesion. The remaining two patients maintained seizures.

CONCLUSIONS

The clinical, imagiological and histopathological data of the six cases presented are generally compatible with those of the reports reviewed by the authors. The imagiological features are nonspecific. Surgical treatment permits histological diagnosis and epilepsy control.

Application of monoclonal antibodies to quality control of foot-and-mouth disease vaccines

Panels of monoclonal antibodies (mAbs) produced against foot-and-mouth disease (FMD) virus types O, A and C were selected for cell culture neutralization titre (NT), mouse protection index (MPI), trypsin sensitivity (TS) and avidity to different epitopes. The selected sets were used to assay the antigen concentration and the fit between FMDV vaccine and challenge strains. It was observed that FMD vaccines protect more than 75% of vaccinated cattle when manufactured with antigens characterized by (1) a high degree of fit with the potency control virus, and (2) mean ELISA 50% titres (T50) > 28 for O, > 18 for A and > 75 for C types, respectively, using the corresponding mAb set.

[The early diagnosis of an acoustic neuroma]

A revision is made of the initial symptoms in acoustic neuroma. The authors propose a study protocol to achieve an early diagnosis of this tumor.