On the mechanism of dendritic fragmentation by ultrasound induced cavitation

A dedicated solidification device and high speed camera were used to capture dendritic fragmentation of pure succinonitrile (SCN) induced by oscillating ultrasonic bubbles. Theoretical analysis of the melting behavior of the dendrite was performed based on local solidification thermodynamics. The dendritic growth or the evolution of the solid-liquid interface is closely related to both thermodynamics of the cavitation bubble and the local geometry of the dendrite. Accordingly, for the first time, a dimensionless scaling formulation was developed by fitting both theoretical and experimental data to determine the variational pressure exerted by the cavitation bubble.

Long-term Outcome of Resective Epilepsy Surgery in Patients With Lennox-Gastaut Syndrome

OBJECTIVE

We aimed to evaluate the long-term outcome of resective epilepsy surgery in patients with Lennox-Gastaut syndrome (LGS).

METHODS

We reviewed the case reports of 90 patients with LGS who had undergone resective surgery between 2003 and 2014 at the Severance Children's Hospital and managed them for a minimum period of 2 years.

RESULTS

At the time of surgery, the patients were between 3.0 and 23.5 years old (mean ± SD: 9.3 ± 4.4). The time from seizure onset to surgery ranged from 0.7 to 20.1 years (7.2 ± 4.3). On postoperative follow-up for an average period of 6.1 ± 2.2 years (range: 2.1-11.4 years), 45 patients (50.0%) had no seizures, and 15 (16.7%) reported infrequent seizures. Seizure-free outcomes were achieved in 15 of the 21 (71.4%) hemispherectomies, 23 of the 51 (45.1%) multilobar resections, and 7 of the 18 (38.9%) single lobar resections. On high-resolution MRIs, 20 patients (22.2%) had negative findings, 8 of whom (40.0%) became seizure-free after resective surgery. Malformation of cortical development was the most common pathologic finding and was noted in 57 patients (63.3%). Seizure-free patients achieved better adaptive behavior and social competence than did patients with persistent seizures at the second (2-3 years after surgery) and third (4-6 years after surgery) follow-ups, as indicated by social quotients (P < .05).

CONCLUSIONS

Resective surgery is a viable option in some patients to treat seizures that are associated with LGS, with a high probability of seizure control and better adaptive function.

Clinical manifestations of headache in children younger than 7 years

PURPOSE

Headache is a common symptom during childhood. It is usually persistent and requires special care. This study aimed to identify the characteristics of headache in children <7 years of age.

METHODS

We reviewed 3 years of clinical files on children <7 years of age with a chief complaint of headache.

RESULTS

This study included 146 children (66 males, 80 females; mean age, 5.5±1.0 years). Mean symptom duration was 5.8±7.9 months. Attack durations were longer than 2 hours in 31 patients, shorter than 2 hours in 70 patients, and unchecked in 45 patients. Attack frequency was 15.1±10.6 times per month. Pain locations and characteristics were also variable. Mean pain severity score was 5.1±2.2 on the visual analog scale. Of 38 patients who underwent electroencephalography, 9 showed positive findings. Of 41 who underwent brain magnetic resonance imaging, 20 showed positive findings. The diagnoses were migraine (including probable migraine) in 34, tension-type headache in 5, and congenital malformations in 3. Medications were used in 29 patients: acetaminophen in 17, ibuprofen in 8, naproxen sodium in 1, and topiramate or amitriptyline in 3.

CONCLUSION

In children aged <7 years, headache has a relatively benign course, but detailed history taking is needed for more accurate diagnosis.

Outcome of ultrasonographic imaging in infants with sacral dimple

Purpose

Sacral dimples are a common cutaneous anomaly in infants. Spine ultrasonography (USG) is an effective and safe screening tool for patients with a sacral dimple. The aim of this study was to determine the clinical manifestations in patients with an isolated sacral dimple and to review the management of spinal cord abnormalities identified with USG.

Methods

We reviewed clinical records and collected data on admissions for a sacral dimple from March 2014 through February 2017 that were evaluated with spine USG by a pediatric radiologist. During the same period, patients who were admitted for other complaints, but were found to have a sacral dimple were also included.

Results

This study included 230 infants under 6-months-old (130 males and 100 females; mean age 52.8±42.6 days). Thirty-one infants with a sacral dimple had an echogenic filum terminale, and 57 children had a filar cyst. Twenty-seven patients had a low-lying spinal cord, and only one patient was suspected of having a tethered cord. Follow-up spine USG was performed in 28 patients, which showed normalization or insignificant change.

Conclusion

In this study, all but one infant with a sacral dimple had benign imaging findings. USG can be recommended in infants with a sacral dimple for its convenience and safety.

Long-term prenatal stress increases susceptibility of N-methyl-D-aspartic acid-induced spasms in infant rats

Purpose

Infantile spasms, also known as West syndrome, is an age-specific epileptic seizure. Most patients with this condition also exhibit delayed development. This study aimed to determine the effect of long-term prenatal stress on susceptibility to infantile spasms.

Methods

We subjected pregnant rats to acute or chronic immobilization stress. Resulting offspring received N-methyl-D-aspartic acid (15 mg/kg, intraperitoneally) on postnatal day 15, and their behaviors were observed 75 minutes after injection. The expression of KCC2 and GAD67 was also determined using immunohistochemistry.

Results

Exposure to long-term prenatal stress increased the frequency of spasms and decreased the latency to onset of spasms compared with offspring exposed to short-term prenatal stress. Expression of KCC2 and GAD67 also decreased in the group exposed to long-term prenatal stress compared with the group exposed to short-term prenatal stress.

Conclusion

Our study suggests that exposure to long-term prenatal stress results in increased susceptibility to seizures.

Temporary Haptic Externalization and Four-point Fixation of Intraocular Lens in Scleral Fixation to Enhance Stability

PURPOSE

To report the results of a new technique for intraocular lens scleral fixation of temporary haptic externalization and four-point fixation for enhanced stability.

METHODS

Two 10-0 polypropylene strands were fixed at two points 2 mm apart on each haptic of a conventional three-piece intraocular lens, using our previously reported method of temporary haptic externalization after injector implantation. Postoperative refractive outcome and stability were evaluated.

RESULTS

Although the intraocular lens was fixed at a total of four points, no intraoperative difficulties were observed during the process. Patients showed successful fixation of the intraocular lens postoperatively. The fixed intraocular lens showed good centering and minimal tilting. When compared to the two-point fixation technique, postoperative astigmatism was significantly smaller in the four-point fixation group (1.80 ± 0.84 vs. 1.00 ± 0.0.50, p = 0.033). Lens-induced astigmatism calculated from subtraction of corneal astigmatism from total astigmatism was also significantly smaller in the four-point fixation group (2.23 ± 0.98 vs.1.17 ± 0.0.70, p = 0.043). No postoperative complications were identified during a mean follow-up period of 14.8 months (range, 10 to 19 months).

CONCLUSIONS

By fixing the intraocular lens at two points on each side of the haptics, this method minimizes the tilting of the intraocular lens and thus decreases postoperative lens-induced astigmatism. Also, the possibility of intraocular lens dislocation in the long term might be decreased by this two-point fixation technique.

Different Clinical Features and Lower Scores in Clinical Scoring Systems for Appendicitis in Preschool Children: Comparison with School Age Onset

PURPOSE

To clarify the clinical features of appendicitis in preschool children and to explore clinical appendicitis scoring systems in this age group.

METHODS

We retrospectively collected data on 142 children, aged 10 years or younger, with confirmed diagnosis of appendicitis based on surgical and pathologic findings. Enrolled subjects were divided into two groups: Group 1 (preschool children aged ≤5 years, n=41) and Group 2 (school children aged >5 to ≤10 years, n=101). Data analyzed included clinical presentation, laboratory findings, the pediatric appendicitis score (PAS), and the modified Alvarado score (MAS).

RESULTS

The most common presenting symptom was abdominal pain in both groups (92.7% vs. 97.0%). Other presenting symptoms were as follows: fever (65.9%), vomiting (68.3%), right lower quadrant (RLQ) localization (24.4%), anorexia (14.6%), and diarrhea (7.3%) in Group 1, and RLQ localization (74.3%), vomiting (71.3%), anorexia (52.5%), fever (47.5%), and diarrhea (11.9%) in Group 2. Perforation and abscess occurred more frequently in Group 1 than in Group 2 (43.9% vs. 12.9%, p<0.001; 34.1% vs. 5.0%, p<0.001; respectively). PAS and MAS were lower in Group 1 than in Group 2 (4.09±1.97 vs. 6.91±1.61, p=0.048; 4.65±1.79 vs. 6.51±1.39, p=0.012; respectively).

CONCLUSION

In preschool children, appendicitis often presents with atypical features, more rapid progression, and higher incidence of complications. This age group is more likely to have lower PAS and MAS than those of school children.

First report of carp oedema virus infection of koi (Cyprinus carpio haematopterus) in the Republic of Korea

Twenty-five koi (Cyprinus carpio haematopterus) bought from a wholesale fish market in Korea, showed lethargic behaviour and 100% mortality within 20 days. Carp oedema virus (CEV) was detected by PCR in all 25 koi. Results of detailed histopathological and clinical examinations of 17 koi indicated loss of body balance, severe infiltration of inflammatory cells into the inter-lamellar spaces of the gills and vacuolization and inclusion bodies in gill epithelial cells. Sequence analysis of PCR products of these koi showed up to 99% identity to the previously reported sequences, suggesting that the observed mass mortality resulted from koi sleepy disease (KSD) due to CEV infection. To the best of our knowledge, this study is the first report of KSD in the Republic of Korea. Partial sequences of 4a protein from the virus indicated that the present CEV detected in koi from Korea is more closely related to that from the UK and Poland than from Japan. The present findings indicate that the prevalence and spread of KSD must be closely monitored in both European and Asian countries to avoid potential economic losses to the global koi industry.

Primary cilia modulate TLR4-mediated inflammatory responses in hippocampal neurons

Background

The primary cilium is an organelle that can act as a master regulator of cellular signaling. Despite the presence of primary cilia in hippocampal neurons, their function is not fully understood. Recent studies have demonstrated that the primary cilium influences interleukin (IL)-1β-induced NF-κB signaling, ultimately mediating the inflammatory response. We, therefore, investigated ciliary function and NF-κB signaling in lipopolysaccharide (LPS)-induced neuroinflammation in conjunction with ciliary length analysis.

Methods

Since TLR4/NF-κB signaling is a well-known inflammatory pathway, we measured ciliary length and inflammatory mediators in wild type (WT) and TLR4^−/− mice injected with LPS. Next, to exclude the effects of microglial TLR4, we examined the ciliary length, ciliary components, inflammatory cytokine, and mediators in HT22 hippocampal neuronal cells.

Results

Primary ciliary length decreased in hippocampal pyramidal neurons after intracerebroventricular injection of LPS in WT mice, whereas it increased in TLR4^−/− mice. LPS treatment decreased primary ciliary length, activated NF-κB signaling, and increased Cox2 and iNOS levels in HT22 hippocampal neurons. In contrast, silencing Kif3a, a key protein component of cilia, increased ARL13B ciliary protein levels and suppressed NF-κB signaling and expression of inflammatory mediators.

Conclusions

These data suggest that LPS-induced NF-κB signaling and inflammatory mediator expression are modulated by cilia and that the blockade of primary cilium formation by Kif3a siRNA regulates TLR4-induced NF-κB signaling. We propose that primary cilia are critical for regulating NF-κB signaling events in neuroinflammation and in the innate immune response.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-0958-7) contains supplementary material, which is available to authorized users.

Use of supplemental anti-HBc testing of donors showing non-discriminating reactive results in multiplex nucleic acid testing

BACKGROUND AND OBJECTIVES

The Korean Red Cross began nucleic acid amplification testing (NAT) for HIV and HCV in February 2005, and added HBV NAT beginning in June 2012. The current NAT system utilizes a multiplex assay for simultaneous detection of HBV DNA, HCV RNA and HIV-1 RNA. For samples that are reactive in the multiplex assay, we do specific tests for each virus. However, there have been cases of non-discriminated reactive (NDR) results which appear to be the result of non-specific reactions or cross-contamination, although some cases are considered to arise from the presence of low levels of HBV DNA due to occult hepatitis B infection.

MATERIALS AND METHODS

We examined the incidence of NDR results in previous donations of some NAT-reactive donors. Additionally, for those donors with NDR results, we performed an HBV core antibody (anti-HBc) assay.

RESULTS

From November 2015 to March 2016, there were 408 NAT-reactive donors. Of these, nineteen HBV NAT-reactive donors showed a history of NDR results in the past donations. Seven donors showed NDR results more than once. Of 771 NDR donors, 362 (47·0%) were anti-HBc reactive.

CONCLUSION

The NDR donors had a substantially higher rate of anti-HBc reactivity than other blood donors indicating that some with anti-HBc reactivity represent donors with occult HBV. Therefore, the incorporation of an anti-HBc testing for NDR donors could improve blood safety testing for the Korean Red Cross.

Altered expression of KCC2 in GABAergic interneuron contributes prenatal stress-induced epileptic spasms in infant rat

Long-term stress during pregnancy causes neurologic deficits to offspring with altered gamma-aminobutyric acid (GABA) system in the brain. However, it is not clear how prenatal stress affects the maturing GABAergic interneurons and the resulting abnormalities in infantile seizures. Here, we showed that prenatal stress alters the maturation of GABA inhibitory system using a seizure model induced by prenatal stress. Prenatal stress with betamethasone or acute immobilization stress (AIS) on gestational day 15 increased the seizure susceptibility to N-methyl-d-aspartate-triggered spasms on postnatal day 15. The expression of GABA was lower in the prenatally stressed group, which compromise the decrease of glutamate decarboxylase 67-immunopositive cells. Prenatal stress markedly decreased the expression of K(+)/Cl(-) co-transporter (KCC2) in the cortex. GABA induced membrane depolarization demonstrated prenatal stress models had significant higher membrane depolarization compared to control. GABA increased KCC2 expression in cultured cortex-containing slices. Taken together, our results showed that prenatal stress with betamethasone or AIS altered the maturation of GABAergic progenitors and resulted in the lack of GABA input, which in turn, decreased KCC2 expression and lowered seizure threshold. We conclude that delayed GABA excitatory/inhibitory shift would render the cortical neuronal circuit more susceptible to excitatory input in prenatal stress induced seizure.

Role of Coronary Artery Calcium Scoring in Detection of Coronary Artery Disease according to Framingham Risk Score in Populations with Low to Intermediate Risks

Current guidelines recommend that coronary artery calcium (CAC) screening should only be used for intermediate risk groups (Framingham risk score [FRS] of 10%-20%). The CAC distributions and coronary artery disease (CAD) prevalence in various FRS strata were determined. The benefit to lower risk populations of CAC score-based screening was also assessed. In total, 1,854 participants (aged 40-79 years) without history of CAD, stroke, or diabetes were enrolled. CAC scores of > 0, ≥ 100, and ≥ 300 were present in 33.8%, 8.2%, and 2.9% of the participants, respectively. The CAC scores rose significantly as the FRS grew more severe (P < 0.01). The total CAD prevalence was 6.1%. The occult CAD prevalence in the FRS ≤ 5%, 6%-10%, 11%-20%, and > 20% strata were 3.4%, 6.7%, 9.0%, and 11.6% (P < 0.001). In multivariate logistic regression analysis adjusting, not only the intermediate and high risk groups but also the low risk (FRS 6%-10%) group had significantly increased odds ratio for occult CAD compared to the very low-risk (FRS ≤ 5%) group (1.89 [95% confidence interval, CI, 1.09-3.29] in FRS 6%-10%; 2.48 [95% CI, 1.47-4.20] in FRS 11%-20%; and 3.10 [95% CI, 1.75-5.47] in FRS > 20%; P < 0.05). In conclusion, the yield of screening for significant CAC and occult CAD is low in the very low risk population but it rises in low and intermediate risk populations.

Chronic inflammatory demyelinating polyneuropathy in children: a report of four patients with variable relapsing courses

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a chronically progressive or relapsing symmetric sensorimotor disorder presumed to occur because of immunologic antibody-mediated reactions. To understand the clinical courses of CIDP, we report variable CIDP courses in children with respect to initial presentation, responsiveness to medical treatment, and recurrence interval. Four patients who were diagnosed with acute-onset and relapsing CIDP courses at Severance Children's Hospital, Seoul, Korea, were enrolled in this retrospective study. We diagnosed each patient on the basis of the CIDP diagnostic criteria developed in 2010 by the European Federation of Neurological Societies/Peripheral Nerve Society Guidelines. We present the cases of four pediatric patients diagnosed with CIDP to understand the variable clinical course of the disease in children. Our four patients were all between 8 and 12 years of age. Patients 1 and 2 were diagnosed with acute cerebellar ataxia or Guillain-Barré syndrome as initial symptoms. While patients 1 and 4 were given only intravenous dexamethasone (0.3 mg/kg/day) for 5 days at the first episode, Patients 2 and 3 were given a combination of intravenous immunoglobulin (2 g/kg) and dexamethasone (0.3 mg/kg/day). All patients were maintained with oral prednisolone at 30 mg/day, but their clinical courses were variable in both relapse intervals and severity. We experienced variable clinical courses of CIDP in children with respect to initial presentation, responsiveness to medical treatment, and recurrence interval.

Growth Differentiation Factor 15 Expression in Astrocytes After Excitotoxic Lesion in the Mouse Hippocampus

Growth differentiation factor 15 (GDF15) is, a member of the transforming growth factor β (TGF-β) superfamily of proteins. Although GDF15 is well established as a potent neurotrophic factor for neurons, little is known about its role in glial cells under neuropathological conditions. We monitored GDF15 expression in astrocyte activation after a kainic acid (KA)-induced neurodegeneration in the ICR mice hippocampus. In control, GDF15 immunoreactivity (IR) was evident in the neuronal layer of the hippocampus; however, GDF15 expression had increased in activated astrocytes throughout the hippocampal region at day 3 after the treatment with KA. LPS treatment in astrocytes dramatically increased GDF15 expression in primary astrocytes. In addition, LPS treatment resulted in the decrease of the IκB-α degradation and increase of the phosphorylation level of RelA/p65. These results indicate that GDF15 has a potential link to NF-κB activation, making GDF15 a valuable target for modulating inflammatory conditions.

Isolated cerebellar variant of adrenoleukodystrophy with a de novo adenosine triphosphate-binding cassette D1 (ABCD1) gene mutation

X-linked adrenoleukodystrophy (X-ALD) shows a wide range of phenotypic expression, but clinical presentation as an isolated lesion of the cerebellar white matter and dentate nuclei has not been reported. We report an unusual presentation of X-ALD only with an isolated lesion of the cerebellar white matter and dentate nuclei. The proband, a 37-year-old man presented with bladder incontinence, slurred speech, dysmetria in all limbs, difficulties in balancing, and gait ataxia. Brain magnetic resonance imaging showed an isolated signal change of white matter around the dentate nucleus in cerebellum. With high level of very long chain fatty acid, gene study showed a de novo mutation in exon 1 at nucleotide position c.277_296dup20 (p.Ala100Cysfs*10) of the adenosine triphosphate-binding cassette D1 gene. It is advised to consider X-ALD as a differential diagnosis in patients with isolated cerebellar degeneration symptoms.

Pathogen inactivation efficacy of Mirasol PRT System and Intercept Blood System for non-leucoreduced platelet-rich plasma-derived platelets suspended in plasma

BACKGROUND AND OBJECTIVES

This study was conducted to evaluate the efficacy of pathogen inactivation (PI) in non-leucoreduced platelet-rich plasma-derived platelets suspended in plasma using the Mirasol PRT System and the Intercept Blood System.

METHODS

Platelets were pooled using the Acrodose PL system and separated into two aliquots for Mirasol and Intercept treatment. Four replicates of each viral strain were used for the evaluation. For bacteria, both low-titre (45-152 CFU/unit) inoculation and high-titre (7·34-10·18 log CFU/unit) inoculation with two replicates for each bacterial strain were used. Platelets with non-detectable bacterial growth and platelets inoculated with a low titre were stored for 5 days, and culture was performed with the BacT/ALERT system.

RESULTS

The inactivation efficacy expressed as log reduction for Mirasol and Intercept systems for viruses was as follows: human immunodeficiency virus 1, ≥4·19 vs. ≥4·23; bovine viral diarrhoea virus, 1·83 vs. ≥6·03; pseudorabies virus, 2·73 vs. ≥5·20; hepatitis A virus, 0·62 vs. 0·76; and porcine parvovirus, 0·28 vs. 0·38. The inactivation efficacy for bacteria was as follows: Escherichia coli, 5·45 vs. ≥9·22; Staphylococcus aureus, 4·26 vs. ≥10·11; and Bacillus subtilis, 5·09 vs. ≥7·74. Postinactivation bacterial growth in platelets inoculated with a low titre of S. aureus or B. subtilis was detected only with Mirasol.

CONCLUSION

Pathogen inactivation efficacy of Intercept for enveloped viruses was found to be satisfactory. Mirasol showed satisfactory inactivation efficacy for HIV-1 only. The two selected non-enveloped viruses were not inactivated by both systems. Inactivation efficacy of Intercept was more robust for all bacteria tested at high or low titres.

The significance of insular hypometabolism in temporal lobe epilepsy in children

BACKGROUND AND PURPOSE

Temporal lobe epilepsy is one of the most common forms of medically refractory epileptic syndromes. In a small percentage, temporal lobectomy fails to control the seizures in patients with epilepsy of clear temporal origin, and in some of these patients, seizures originating from the insular cortex is believed to be the cause behind the surgical failures. We retrospectively analyzed the [(18)F]FDG-positron emission tomography (PET) results of patients who received temporal lobe surgery for presence of insular hypometabolism, and compared the surgical outcome to verify whether insular hypometablism was related with difference in post-operative results.

METHODS

13 patients were enrolled, and clinical variables, post-operative pathology, magnetic resonance imaging and PET results were analyzed for possible differences between the patients with or without insular hypometabolism.

RESULTS

7 patients showed insular hypometabolism, while 6 patients were clear of insular lesion on PET exam. 8 patients received anterior temporal lobectomy with amygdalohippocampectomy (AH), 2 patients received radical temporal lobectomy with AH, and 3 patients received insular cortisectomy. Post-operative results were favorable in 8 patients and unfavorable in 5, with unfavorable outcomes in all recipients of insular cortisectomy. Presence of insular hypometabolism did not have any significant relationship with the post-surgical outcome (p=0.266), but its trend showed a tendency towards favorable outcome if insular hypometabolism was not present.

CONCLUSIONS

Presence of insular hypometabolism in [(18)F]FDG-PET analysis was not significantly correlated with the post-operative outcome, and recipients of insular cortisectomy among our patients with insular hypometabolism resulted in poor surgical outcome. However, the outcome trend showed a tendency towards better surgical outcome with absence of hypometabolic lesion in the ipsilateral insular cortex. Further studies employing a larger patient group is needed.

Seizure outcome of infantile spasms with focal cortical dysplasia

PURPOSE

This study sought to evaluate the seizure outcome of infantile spasms (IS) with focal cortical dysplasia (FCD).

METHODS

We retrospectively reviewed infantile spasms patients with FCD from 2004 to 2010. We investigated seizure outcome from antiepileptic drug (AED), ketogenic diet (KD), resective surgery, and analyzed the results according to individual imaging studies.

RESULTS

Among 404 patients of IS, FCD was confirmed in 51 patients. In retrospective review of brain MRI, only 21 patients (41.2%) were suspected of FCD before 1year of age, but 45 patients (88.2%) became confirmed to FCD by MRI after the age of 1year. Once the spasms were not controlled by 1 or 2 AEDs, the chance of becoming seizure free with additional third or more drugs was very low (2.3%). The seizure free rate was 33.3% (7/21) in patients treated with ketogenic diet, and 73.3% (22/30) in surgical patients, who were both intractable to AEDs. There were no significant differences in seizure free rate in both ketogenic diet and surgical patients, between MRI negative and positive patients prior to 1year of age.

CONCLUSIONS

KD and surgery should be considered in medically refractory IS with FCD.

IQGAP1 expression in spared CA1 neurons after an excitotoxic lesion in the mouse hippocampus

Repeated seizures induce permanent alterations in the hippocampal circuits in experimental models with intractable temporal lobe epilepsy. Sprouting and synaptic reorganization induced by seizures has been well-studied in the mossy fiber pathway. However, studies investigating sprouting and synaptic reorganization beyond the mossy fiber pathway are limited. The present study examined the biochemical changes of CA1 pyramidal neurons undergoing morphological changes after excitotoxicity-induced hippocampal CA3 neuronal death. IQ-domain GTPase-activating proteins (IQGAP1), is an effector of Rac1 and Cdc42 and an actin-binding protein, was upregulated in CA1 pyramidal neurons after kainic acid-induced hippocampal CA3 neuronal degeneration. IQGAP1 + cells were colocalized with Nestin, but not in astrocytes or mature neurons. Furthermore, IQGAP1 did not originate from newly divided local precursors or NG2 + cells. IQGAP1 and adenomatous polyposis coli localized in CA1 pyramidal neurons, and Cdc42 activation was followed by IQGAP1 recruitment. These findings suggest that IQGAP1 is upregulated in pre-existed sparing neurons of the CA1 layer undergoing morphological changes after excitoxicity-induced hippocampal CA3 neuronal death. It demonstrates the utility of IQGAP1 as a possible marker for spared pyramidal neurons, which may contribute to structural and functional alternations responsible for the development of epilepsy.