Temporal evolution of postsurgical bone repair in a rabbit model: A [99mTc]Tc-MDP scintigraphic study

Bone regeneration is crucial for repairing bone tissue following various injuries. Research techniques that enable the study of metabolic changes in bone tissue under different conditions are important for understanding bone repair and remodeling. This study used bone scintigraphy to evaluate osteogenesis secondary to osteotomy in a preclinical model of New Zealand rabbits. For this purpose, we conducted a longitudinal, prospective, case-control study in which scintigraphic variables were measured in both the right forearm (case-operated) and the left forearm (control - non-operated). The study sample consisted of 10 rabbits subjected to osteotomy, followed by a 12-week postoperative evaluation period, divided into six imaging stages at 1, 2, 3, 4, 8, and 12 weeks. We observed that the operated forearm showed significantly higher external radiation than the control side, using the pinhole collimator, denoting an increase in the biodistribution and tropism of the radiopharmaceutical to the operated forearm. Among the three evaluated time points, osteoblastic activity was highest in the second week and presented a significant decline in the 8th and 12th weeks, denoting regeneration and resolution of the surgical injury; the control forearm was also influenced by the inactivity imposed by the operated forearm. This fact was notably evidenced by the reduction in the metabolic activity of osteoblasts in the left forearm. Our study suggested that bone scintigraphy was sensitive enough to semi-quantitatively differentiate the metabolic activity of osteoblasts in the operated forearm in the three temporal landmarks evaluated in the study.

Automating behavioral analysis in neuroscience: Development of an open-source python software for more consistent and reliable results

BACKGROUND

The application of automated analyses in neuroscience has become a practical approach. With automation, the algorithms and tools employed perform fast and accurate data analysis. It minimizes the inherent errors of manual analysis performed by a human experimenter. It also reduces the time required to analyze a large amount of data and the need for human and financial resources.

METHODS

In this work, we describe a protocol for the automated analysis of the Morris Water Maze (MWM) and the Open Field (OF) test using the OpenCV library in Python. This simple protocol tracks mice navigation with high accuracy.

RESULTS

In the MWM, both automated and manual analysis revealed similar results regarding the time the mice stayed in the target quadrant (p = 0.109). In the OF test, both automated and manual analysis revealed similar results regarding the time the mice stayed in the center (p = 0.520) and in the border (p = 0.503) of the field.

CONCLUSIONS

The automated analysis protocol has several advantages over manual analysis. It saves time, reduces human errors, can be customized, and provides more consistent information about animal behavior during tests. We conclude that the automated protocol described here is reliable and provides consistent behavioral analysis in mice. This automated protocol could lead to deeper insight into behavioral neuroscience.

Medical image registration using TSallis Entropy in Statistical Parametric Mapping (SPM)

The superposition of medical images, technically known as co-registration, can take a major role in determining the topographic and morphological changes in functional diagnostic and therapeutic purposes. This paper describes a study focused on to find an alternative cost function method for medical images co-registration through the study of performance and robustness of the TSallis Entropy in Statistical Parametric Mapping package (SPM). Images of Magnetic Resonance (MR) and Single Photon Emission Computed Tomography (SPECT) of 3 patients morphologically normal were used for the construction of anatomic phantoms containing predetermined geometric variations. The simulated images were co-registered with the original images using traditional techniques and the proposed method. The comparative analysis of the Root Mean Square (RMS) error showed that the Tsallis Entropy was more efficient in the intramodality alignment, while the Shannon Entropy in the intermodality one; revealing therefore the importance of the implementation of the Tsallis Entropy in SPM for applications in neurology and neuropsychiatric evaluation.

Suppression of obsessive-compulsive symptoms after epilepsy surgery

We report two male patients with medically intractable epilepsy and obsessive-compulsive disorder (OCD) symptoms. Both patients experienced remission of obsessive-compulsive symptoms after surgical treatment of epilepsy. Although the surgeries targeted different brain regions, the two patients had in common unilateral anterior cingulate cortex ablation. On the basis of these observations, we discuss the pathophysiology of OCD symptoms, emphasizing the role of corticosubcortical pathways in their genesis. Our data suggest that surgeries that affect neural loops associated with obsessive-compulsive symptoms can lead to an improvement of OCD; however, the structures responsible for this effect cannot be conclusively determined.

Cognitive performance of patients with mesial temporal lobe epilepsy and incidental calcified neurocysticercosis

OBJECTIVES

Although chronic calcified neurocysticercosis (NCC) has been considered a major cause of symptomatic epilepsy in developing countries, it can also be an incidental pathological finding in epileptic patients from endemic regions. The mechanisms of brain plasticity occurring in patients with NCC during and after the inflammatory process related to the parasite infection, death, degeneration, and calcification within the host brain might be an independent factor for cognitive impairment in patients with NCC and epilepsy. In order to assess this possibility cognitive performance of patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) with and without NCC was investigated through structured neuropsychological testing.

METHODS

Cognitive performance of long term MTLE-HS patients with (HS-NCC group, n = 32) and without NCC (HS only, n = 48) was compared. Imbalances between the two groups with respect to clinical, demographic, neuroimaging, and electrophysiological variables were adjusted by linear multiple regression analysis and Bonferroni correction for multiple tests.

RESULTS AND CONCLUSIONS

There were no cognitive performance differences between HS-NCC and HS only patients, leading to the conclusion that chronic calcified NCC per se does not aggravate the cognitive performance of patients with long term MTLE-HS.

Cortical malformations are associated with a rare polymorphism of cellular prion protein

Studies in animals lacking the cellular prion protein (PrP(c)) gene (Prnp) showed higher neuronal excitability in vitro and increased sensitivity to seizures in vivo. The authors previously reported a rare polymorphism at codon 171 (Asn-->Ser) of human Prnp to be associated with mesial temporal lobe epilepsy related to hippocampal sclerosis. They demonstrated that the same variant allele is also associated with symptomatic epilepsies related to different forms of malformations of cortical development.

Surgical outcome in mesial temporal sclerosis correlates with prion protein gene variant

BACKGROUND

Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) is the most common surgically remediable epileptic syndrome. Ablation of the cellular prion protein (PrP(c)) gene (PRNP) enhances neuronal excitability of the hippocampus in vitro and sensitivity to seizure in vivo, indicating that PrP(c) might be related to epilepsy.

OBJECTIVE

To evaluate the genetic contribution of PRNP to MTLE-HS.

METHODS

The PRNP coding sequence of DNA from peripheral blood cells of 100 consecutive patients with surgically treated MTLE-HS was compared to that from a group of healthy controls adjusted for sex, age, and ethnicity (n = 180). The presence of PRNP variant alleles was correlated with clinical and presurgical parameters as well as surgical outcome.

RESULTS

A variant allele at position 171 (Asn-->Ser), absent in controls, was found in heterozygosis (Asn171Ser) in 23% of patients (p < 0.0001). The PRNP genotypes were not correlated with any clinical or presurgical data investigated. However, patients carrying the Asn171Ser variant had a five times higher chance of continuing to have seizures after temporal lobectomy (95% CI 1.65 to 17.33, p = 0.005) than those carrying the normal allele. At 18 months after surgery, 91.8% of patients with the normal allele at codon 171 were seizure free, in comparison to 68.2% of those carrying Asn171Ser (p = 0.005).

CONCLUSIONS

The PRNP variant allele Asn171Ser is highly prevalent in patients with medically untreatable MTLE-HS and influences their surgical outcome. The results suggest that the PRNP variant allele at codon 171 (Asn171Ser) is associated with epileptogenesis in MTLE-HS.

Accuracy of ictal SPECT in mesial temporal lobe epilepsy with bilateral interictal spikes

OBJECTIVE

In mesial temporal lobe epilepsy (MTLE), the rate of correct seizure lateralization of ictal semiology and ictal EEG is better for patients with unilateral interictal spikes (UIS) than for patients with bilateral interictal spikes (BIS), possibly due to rapid seizure propagation patterns associated with bilateral epileptogenesis. In this study, the authors investigated if ictal SPECT is a reliable diagnostic test for both UIS and BIS patients.

METHODS

Video-EEG recording was used as the gold standard to examine the accuracy of ictal SPECT and its relationship with interictal and ictal EEG. Ninety-three consecutive patients with MTLE associated with hippocampal sclerosis were included in the analysis. Ictal SPECT was considered accurate if two blinded observers independently lateralized the scan correctly.

RESULTS

Ictal SPECT correctly lateralized 75 (80.6%) of 93 scans. The rate of correct seizure lateralization was 87.6% for the UIS group and only 55.0% for the BIS group (p = 0.0027). In the EEG epochs, 66.7% of BIS patients vs 43.4% of UIS patients had nonlateralized ictal EEG (p < 0.001).

CONCLUSION

The authors conclude that the accuracy of ictal SPECT is worse for MTLE patients with BIS than for those with UIS. The role of ictal SPECT in presurgical evaluation of patients with BIS must be reviewed.

Typical and atypical perfusion patterns in periictal SPECT of patients with unilateral temporal lobe epilepsy

PURPOSE

To characterize perfusion patterns of periictal single-photon emission tomography (SPECT) in patients with unilateral temporal lobe epilepsy (TLE) and to determine their relationship to the epileptogenic zone (EZ).

METHODS

We studied periictal SPECT scans of 53 patients after anterior mesial temporal lobectomy who had good seizure outcome after surgery. Ictal SPECT scans were performed during video-EEG monitoring. Typical SPECT patterns consisted of ipsilateral ictal hyperperfusion or ipsilateral postictal hypoperfusion. Atypical ictal patterns included normal scans, bilateral temporal hyperperfusion, or contralateral patterns. These perfusion patterns were retrospectively analyzed searching for concordance rate with the EZ.

RESULTS

We obtained 51 ictal and two early postictal scans. In the typical group, 40 (75.4%) patients had ipsilateral ictal temporal lobe hyperperfusion, and one (1.9%) patient had ipsilateral postictal temporal lobe hypoperfusion. Twelve (22.7%) patients exhibited atypical perfusion patterns: seven (13.2%) patients had bitemporal ictal hyperperfusion (four cases showed asymmetric temporal lobe changes), four (7.6%) patients had contralateral hyperperfusion, and one (1.9%) patient had a normal SPECT scan. All four patients with bitemporal asymmetric hyperperfusions showed greater perfusion lateralized to the side of the EZ. Three of the four patients who had contralateral hyperperfusion also had a complex postictal-like pattern in the ipsilateral temporal lobe consisting of anteromesial hyperperfusion with adjacent lateral hypoperfusion.

CONCLUSIONS

This study analyzed typical and atypical perfusion patterns in unilateral TLE, and suggested that not only typical, but also some atypical perfusion patterns may contribute to the lateralization of EZ.