A novel categorization of the muscular branches of the tibial nerve within the popliteal fossa

BACKGROUND

The muscular branches of the tibial nerve within the popliteal fossa innervate the gastrocnemius, soleus, plantaris, and popliteus muscles. Various branching patterns have been described in textbooks; however, the underlying fundamental rules explaining the patterns remain unclear. Understanding the fundamental rule explaining the branching pattern of the innervating nerves is essential for understanding the ontogeny of skeletal muscles. Therefore, this study aimed at establishing a theory to explain the branching pattern of the muscular branches of the tibial nerve within the popliteal fossa.

METHODS

The branching patterns of the muscular branches of the tibial nerve within the popliteal fossa were examined macroscopically in 62 lower limbs derived from 31 adult cadavers (22 males and 9 females, aged 49-95 years).

RESULTS

The branch to the medial head of the gastrocnemius muscle invariably arose from the posteromedial side of the tibial nerve. The branches to the soleus muscle and lateral head of the gastrocnemius muscle had a common trunk in all the lower limbs and invariably arose from the posterolateral side. The branches to the plantaris and popliteus muscles arose anteriorly from the tibial nerve in this order (plantaris branch first, followed by the popliteus branch). These branches invariably arose more distally than the branch to both the heads of the gastrocnemius and soleus muscles.

CONCLUSIONS

Based on these fundamental branching patterns, we suggest a novel branching categorization. The branches could be categorized into a posterior group and an anterior group, which has independent branches to the plantaris and popliteus muscles. This fundamental branching pattern and novel categorization contribute to the understanding of the ontogeny of the skeletal muscles around the flexor compartment of the leg.

A bilateral third head of the gastrocnemius which is morphologically similar to the plantaris

PURPOSE

An extra muscle was observed on both sides of the popliteal fossa in the cadaver of a 78-year-old Japanese male during dissection. The aim of this case report was to identify whether this variant is a double plantaris or a third head of the gastrocnemius according to its morphological characteristics and innervation.

METHODS

The muscles were displayed by careful dissection and delineation of surrounding structures. The size of each of the muscle bellies and tendons of those extra muscles were measured manually by the vernier caliper.

RESULTS

The origin of each extra muscle was lateral to the tibial nerve and superior to the plantaris, and each extra muscle which transitioned to a descending tendon parallel to the plantaris had a cone-shaped belly. However, the tendon of the extra muscles was fused into the investing fascia of the gastrocnemius with a tendon length of 4.5 cm on the left and 4.6 cm on the right. The extra muscles were innervated by the branch of the tibial nerve to the medial head of the gastrocnemius on both sides.

CONCLUSION

Although they had an origin and shape similar to that of the plantaris, we identified the extra muscles in this case as a third head of the gastrocnemius, because of innervation to the plantaris arises directly from the tibial nerve. This case highlighted that the innervation is essential to understanding the myogenesis of extra muscles, especially in cases which are difficult to categorize based on the morphological features of the muscle.

Positive association between the cross-sectional area of the rhomboid muscle, and the range of shoulder abduction after neck dissection surgery

OBJECTIVE

To evaluate the association between the cross-sectional area of selected shoulder and scapular muscles and the range of shoulder abduction, early after neck dissection surgery.

PATIENTS AND METHODS

Twenty-seven patients (contributing 34 upper limbs), who had undergone neck dissection surgery for head and neck malignancy, were enrolled into the study. Loss of strength of the trapezius muscle at 1-month post-surgery was quantified by the change in active range of shoulder abduction (%A-ROM), measured by hand-held goniometry in a standing position, from baseline, before surgery. The cross-sectional area of the following muscles were measured on unenhanced computed tomography images after surgery: trapezius, rhomboid, serratus anterior, pectoralis major, deltoid, and biceps brachii.

RESULTS

There was a significant positive correlation between the %A-ROM and the cross-sectional area of the rhomboid muscle.

CONCLUSION

Greater active shoulder abduction early after surgery is associated with a greater cross-sectional area of the rhomboid muscle. This muscle should be included in intensive programs for rehabilitation of upper limb movement after neck dissection surgery.

Intravenous anesthetic-induced calcium dysregulation and neurotoxic shift with age during development in primary cultured neurons

Anesthetic-induced neurotoxicity in the developing brain is a concern. This neurotoxicity is closely related to anesthetic exposure time, dose, and developmental stages. Using calcium imaging and morphological examinations in vitro, we sought to determine whether intravenous anesthetic-induced direct neurotoxicity varies according to different stages of the days in vitro (DIV) of neurons in primary culture. Cortical neurons from E17 Wistar rats were prepared. On DIV 3, 7, and 13, cells were exposed to the intravenous anesthetics thiopental sodium (TPS), midazolam (MDZ), or propofol (PPF), to investigate direct neurotoxicity using morphological experiments. Furthermore, using calcium imaging, the anesthetic-induced intracellular calcium concentration ([Ca²⁺]i) elevation was monitored in cells on DIV 4, 8, and 13. All anesthetics elicited significant [Ca²⁺]i increases on DIV 4. While TPS (100 μM) and MDZ (10 μM) did not alter neuronal death, PPF (10 μM and 100 μM) decreased the survival ratio (SR) significantly. On DIV 8, TPS and MDZ did not elicit [Ca²⁺]i elevation or SR decrease, while PPF still induced [Ca²⁺]i elevation (both at 10 μM and 100 μM) and significant SR decrease at 100 μM (0.76 ± 0.03; P < 0.05), but not at 10 μM (0.91 ± 0.03). Such anesthetic-induced [Ca²⁺]i elevation and SR decrease were not observed on DIV 13-14 for any of the anesthetic drugs. Our study indicates that more caution may be exercised when using PPF compared to TPS or MDZ during development.

Responses of Korean physical therapy students after practice with a virtual anatomical system in Japan

[Purpose] To investigate responses of Korean physical therapy students, receiving medical terminology education in physical therapy both in Korean and English, after practice with a virtual anatomical system. [Subjects and Methods] The participants were 25 physical therapy students from Konyang University in South Korea visiting the International University of Health and Welfare for training purposes. The virtual anatomy practice was conducted in English using 3 dimensional virtual anatomy software constructed using real cadaver photographs. A questionnaire about this practice and anatomy was completed after the practice. [Results] The results of the questionnaire showed a trend toward high scores for virtual anatomy practice. [Conclusion] The present virtual anatomy system was created using multi-directional photographs from a real cadaver; therefore, it can be used as an auxiliary means of education using cadavers.

Microstructural Differences in the Corpus Callosum in Patients With Bipolar Disorder and Major Depressive Disorder

OBJECTIVE

It is difficult to distinguish between bipolar disorder and major depressive disorder (MDD) in patients lacking a clear history of mania. There is an urgent need for an objective biomarker for differential diagnosis. Using diffusion tensor imaging, this study investigated the differences in the brain white matter microstructure between patients with bipolar disorder and MDD.

METHODS

Participants included 16 patients with bipolar disorder and 23 patients with MDD having depressed or euthymic states based on DSM-IV-TR criteria and 23 healthy volunteers. Whole-brain voxel-based morphometric analysis was used to detect any significant differences in fractional anisotropy between patients with bipolar disorder and MDD. The study was conducted between August 2011 and July 2015.

RESULTS

We found a significant decrease in fractional anisotropy values in the anterior part of the corpus callosum in patients with bipolar disorder compared with MDD (P < .001), which did not depend on the patients' affective state. This decrease was associated with increased radial diffusivity values (P < .05), which was also found in patients with bipolar disorder when compared with healthy volunteers (P < .05). We predicted bipolar disorder and MDD in all patients using the fractional anisotropy values, with a correct classification rate of 76.9%.

CONCLUSIONS

The present study revealed that patients with bipolar disorder have microstructural abnormalities in the corpus callosum during depressed or euthymic states, which may deteriorate the exchange of emotional information between the cerebral hemispheres, resulting in emotional dysregulation. Our results indicate the possible use of diffusion tensor imaging as a differential diagnostic tool.

Test-retest reproducibility of extrastriatal binding with 123I-FP-CIT SPECT in healthy male subjects

¹²³I-labeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (¹²³I-FP-CIT) is used to assess striatal dopamine transporter (DAT) expression, but it can also quantify extrastriatal serotonin transporter (SERT) expressions. While FP-CIT uptake in extrastriatal regions has been quantified, no information exists on the reproducibility of the ¹²³I-FP-CIT specific uptake ratio (SUR) in extrastriatal regions. We investigated test-retest reproducibility of ¹²³I-FP-CIT binding in the striatum, the midbrain, and cortical regions in eight healthy male subjects. All subjects underwent two ¹²³I-FP-CIT SPECT scans, and SUR was calculated using the cerebellum as the reference. We found good test-retest reproducibility of ¹²³I-FP-CIT SUR in the midbrain, and in the lateral frontal/temporal cortex and combined cortical regions. The overall variability and intraclass correlation of SUR were, respectively, 4.9-7.8% and 0.90-0.96 in striatal regions, 8.6% and 0.79 in the midbrain, and 3.6-9.1% and 0.84-0.95 in the lateral frontal/temporal cortex and combined cortical regions. Our results provide evidence that ¹²³I-FP-CIT SPECT is a valid technique for analyzing striatal DAT, as well as extrastriatal SERT in areas such as the SERT-enriched midbrain. In addition, our data suggest that ¹²³I-FP-CIT could be used for analyzing SERT in regions with relatively low SERT expression (e.g., temporal or frontal cortices).

High amyloid-β deposition related to depressive symptoms in older individuals with normal cognition: a pilot study

OBJECTIVE

Previous studies have reported depressive symptoms in the preclinical stages of Alzheimer's disease (AD). The objective of this study was to determine whether depressive symptoms are associated with cortical amyloid burden. In order to do this, we measured cortical amyloid via (11) C-labeled Pittsburgh Compound B ([(11) C]PIB) uptake using positron emission tomography (PET) in cognitively normal subjects.

METHODS

We performed [(11) C]PIB-PET in 29 cognitively normal, older participants. Depressive symptoms were assessed using the 15-item Geriatric Depression Scale (GDS). Aβ deposition was quantified by binding potential (BPND ), and the association between cortical mean BPND values and GDS scores was evaluated. Analysis of parametric BPND images was performed to examine the relationship between regional BPND and GDS scores.

RESULTS

We found a positive correlation between depressive symptoms and mean cortical PIB-BPND in groups of subjects with middle to high PIB-BPND . There was little change in GDS-depression score between subjects with low and middle PIB-BPND levels, while an increase in GDS was shown in the high PIB-BPND group. The main BPND increase was localized to the precuneus/posterior cingulate cortex (PCu/PCC) in subjects with high PIB-BPND , and we found a significant positive relationship between PIB-BPND in this area and depressive symptoms.

CONCLUSIONS

Emotional dysregulation because of Aβ neuropathology in the PCu/PCC may relate to depressive symptoms. More specifically, we found that older, cognitively normal patients with depressive episodes were more likely to have underlying AD pathology. Thus, depressive symptoms may increase the predictive ability of the identification of future AD cases. Copyright © 2016 John Wiley & Sons, Ltd.

Thiopental sodium preserves the responsiveness to glutamate but not acetylcholine in rat primary cultured neurons exposed to hypoxia

Although many in vitro studies demonstrated that thiopental sodium (TPS) is a promising neuroprotective agent, clinical attempts to use TPS showed mainly unsatisfactory results. We investigated the neuroprotective effects of TPS against hypoxic insults (HI), and the responses of the neurons to l-glutamate and acetylcholine application. Neurons prepared from E17 Wistar rats were used after 2weeks in culture. The neurons were exposed to 12-h HI with or without TPS. HI-induced neurotoxicity was evaluated morphologically. Moreover, we investigated the dynamics of the free intracellular calcium ([Ca(2+)]i) in the surviving neurons after HI with or without TPS pretreatment following the application of neurotransmitters. TPS was neuroprotective against HI according to the morphological examinations (0.73±0.06 vs. 0.52±0.07, P=0.04). While the response to l-glutamate was maintained (0.89±0.08 vs. 1.02±0.09, P=0.60), the [Ca(2+)]i response to acetylcholine was notably impaired (0.59±0.02 vs. 0.94±0.04, P<0.01). Though TPS to cortical cultures was neuroprotective against HI morphologically, the [Ca(2+)]i response not to l-glutamate but to acetylcholine was impaired. This may partially explain the inconsistent results regarding the neuroprotective effects of TPS between experimental studies and clinical settings.

Comparative morphology and development of extra-ocular muscles in the lamprey and gnathostomes reveal the ancestral state and developmental patterns of the vertebrate head

The ancestral configuration of the vertebrate head has long been an intriguing topic in comparative morphology and evolutionary biology. One peculiar component of the vertebrate head is the presence of extra-ocular muscles (EOMs), the developmental mechanism and evolution of which remain to be determined. The head mesoderm of elasmobranchs undergoes local epithelialization into three head cavities, precursors of the EOMs. In contrast, in avians, these muscles appear to develop mainly from the mesenchymal head mesoderm. Importantly, in the basal vertebrate lamprey, the head mesoderm does not show overt head cavities or signs of segmental boundaries, and the development of the EOMs is not well described. Furthermore, the disposition of the lamprey EOMs differs from those the rest of vertebrates, in which the morphological pattern of EOMs is strongly conserved. To better understand the evolution and developmental origins of the vertebrate EOMs, we explored the development of the head mesoderm and EOMs of the lamprey in detail. We found that the disposition of lamprey EOM primordia differed from that in gnathostomes, even during the earliest period of development. We also found that three components of the paraxial head mesoderm could be distinguished genetically (premandibular mesoderm: Gsc+/TbxA-; mandibular mesoderm: Gsc-/TbxA-; hyoid mesoderm: Gsc-/TbxA+), indicating that the genetic mechanisms of EOMs are conserved in all vertebrates. We conclude that the tripartite developmental origin of the EOMs is likely to have been possessed by the latest common ancestor of the vertebrates. This ancestor's EOM developmental pattern was also suggested to have resembled more that of the lamprey, and the gnathostome EOMs' disposition is likely to have been established by a secondary modification that took place in the common ancestor of crown gnathostomes.

A structural model of age, grey matter volumes, education, and personality traits

BACKGROUND

When the relationship between ageing and changes in personality traits is considered, it is important to know how they are influenced by biological and environmental factors. The present study examined the relationships between various factors associated with the effect of ageing on personality traits, including structural changes of the brain and environmental factors such as education.

METHODS

We recruited 41 healthy subjects. We administered the NEO Five-Factor Inventory to assess personality factors. Magnetic resonance imaging was performed, and regional grey matter (GM) volumes were obtained. We identified associations in the correlation analysis of age, cerebral GM volume, years of education, and the personality trait of openness. Path analysis was used to estimate the relationships among these factors.

RESULTS

The path analysis model of age, GM volume, years of education, and the personality trait of openness revealed that age has an indirect negative association with openness through GM volume and years of education. Ageing was related to a decrease in GM volume, which was in turn related to a decrease in the openness score. Older subjects generally had fewer years of education, which was related to a lower openness score.

CONCLUSIONS

Maintaining openness against the effects of ageing is desirable, and our results imply that interventions against age-related cerebral atrophy and the promotion of opportunities for higher education may contribute to the development and stability of a healthy personality during the adult life course.

Low amyloid-β deposition correlates with high education in cognitively normal older adults: a pilot study

OBJECTIVE

Several epidemiological studies have found a lower incidence of Alzheimer's disease in highly educated populations, but the protective mechanism of education against the disease is still unclear. Our objective was to investigate the association between education and (11) C-labeled Pittsburgh Compound B (PIB) uptake with positron emission tomography in participants with normal cognitive ability.

METHODS

We performed (11) C-labeled PIB positron emission tomography and neuropsychological testing in 30 cognitively normal older participants. Of the participants, 16 had a period of education less than 12 years (low-education group) and 14 had more than 13 years (high-education group). Amyloid-β deposition was quantified by binding potential (BPND ) in several brain regions and was compared between the groups with different education levels.

RESULTS

We found significantly higher cortical PIB-BPND in the cognitively normal participants with low education compared with the ones with high education. None of the brain regions in low-education group showed significantly lower BPND values. This finding was not affected by the inclusion of possible confounding variables such as age, sex, and general intelligence. Our findings indicated a reduced amyloid pathology in highly educated, cognitively normal, participants.

CONCLUSIONS

Our findings lead to the proposal that early-life education has a negative association with Alzheimer's disease pathology. This proposal is not in opposition to the brain reserve hypothesis. People with more education might be prone to a greater inhibitory effect against amyloid-β deposition before the preclinical stage. At the same time, they have a greater reserve capacity, and greater pathological changes are required for dementia to manifest.

Delayed atrophy in posterior cingulate cortex and apathy after stroke

OBJECTIVE

A few studies have been performed on chronic structural changes after stroke. The primary purpose of the present study was to investigate regional cortical volume changes after the onset of stroke and to examine how the cortical volume changes affected neuropsychiatric symptoms.

METHODS

Participants were 20 stroke patients and 14 control subjects. T1-MRI was performed twice, once at the subacute stage and again 6 months later, and whole brain voxel-based morphometric (VBM) analysis was used to detect significant cortical gray matter volume changes in patients. We also assessed the correlation between changes in cortical volumes and changes in neuropsychiatric symptoms during the 6 months following a stroke.

RESULTS

In the present study, we found significant volume reductions in the anterior part of the posterior cingulate cortex (PCC) over the 6 months following a stroke by exploratory VBM analysis. We also found that the amount of volume change was significantly correlated with the change in apathy-scale scores during the 6 months poststroke.

CONCLUSIONS

The present study suggests that delayed atrophic change is evident in the PCC 6 months after a stroke. There was greater apathetic change in the stroke patients with the larger volume reductions. The delayed atrophy of the PCC may reflect degeneration secondary to neuronal loss due to stroke. Such degeneration might have impaired control of goal-directed behavior, leading to the observed increase in apathy.

Organization and cellular arrangement of two neurogenic regions in the adult ferret (Mustela putorius furo) brain

In the adult mammalian brain, two neurogenic regions have been characterized, the subventricular zone (SVZ) of the lateral ventricle (LV) and the subgranular zone (SGZ) of the dentate gyrus (DG). Despite remarkable knowledge of rodents, the detailed arrangement of neurogenic regions in most mammals is poorly understood. In this study, we used immunohistochemistry and cell type-specific antibodies to investigate the organization of two germinal regions in the adult ferret, which belongs to the order Carnivora and is widely used as a model animal with a gyrencephalic brain. From the SVZ to the olfactory bulb, doublecortin-positive cells tended to organize in chain-like clusters, which are surrounded by a meshwork of astrocytes. This structure is homologous to the rostral migratory stream (RMS) described in other species. Different from rodents, the horizontal limb of the RMS emerges directly from the LV, and the anterior region of the LV extends rostrally and reached the olfactory bulb. In the DG, glial fibrillary acidic protein-positive cells with long radial processes as well as doublecortin-positive cells are oriented in the SGZ. In both regions, doublecortin-positive cells showed characteristic morphology and were positive for polysialylated-neural cell adhesion molecule, beta-III tubulin, and lamin B1 (intense staining). Proliferating cells were detected in both regions using antibodies against proliferating cell nuclear antigen and phospho-histone H3. These observations demonstrate that the two neurogenic regions in ferrets have a similar cellular composition as those of other mammalian species despite anatomical differences in the brain.

Increased binding of 5-HT1A receptors in a dissociative amnesic patient after the recovery process

Dissociative amnesia is characterized by an inability to retrieve information already saved in memories. 5-HT has some role in neural regulatory control and may be related to the recovery from dissociative amnesia. To examine the role of 5-HT1A receptors in the recovery from dissociative amnesia, we performed two positron emission tomography (PET) scans on a 30-year-old patient of dissociative amnesia using [(11)C]WAY-100635, the first at amnesic state, and the second at the time he had recovered. Exploratory voxel-based analysis (VBA) was performed using SPM software. 5-HT1A BPND images were compared between the patient at amnesic and recovery states and healthy subjects (14 males, mean age 29.8 ± 6.45) with Jack-knife analysis. 5-HT1A receptor bindings of the patient at the recovery state were significantly higher than those of healthy subjects in the right superior and middle frontal cortex, left inferior frontal and orbitofrontal cortex and bilateral inferior temporal cortex. The increase in BPND values of recovery state was beyond 10% of those of amnesia state in these regions except in the right superior frontal cortex. We considered that neural regulatory control by the increase of 5-HT1A receptors in cortical regions played a role in the recovery from dissociative amnesia.

Gray and white matter changes in subjective cognitive impairment, amnestic mild cognitive impairment and Alzheimer's disease: a voxel-based analysis study

Subjective cognitive impairment may be a very early at-risk period of the continuum of dementia. However, it is difficult to discriminate at-risk states from normal aging. Thus, detection of the early pathological changes in the subjective cognitive impairment period is needed. To elucidate these changes, we employed diffusion tensor imaging and volumetry analysis, and compared subjective cognitive impairment with normal, mild cognitive impairment and Alzheimer's disease. The subjects in this study were 39 Alzheimer's disease, 43 mild cognitive impairment, 28 subjective cognitive impairment and 41 normal controls. There were no statistically significant differences between the normal control and subjective cognitive impairment groups in all measures. Alzheimer's disease and mild cognitive impairment had the same extent of brain atrophy and diffusion changes. These results are consistent with the hypothetical model of the dynamic biomarkers of Alzheimer's disease.

Microstructural abnormalities in white matter and their effect on depressive symptoms after stroke

The aim of the study was to investigate the existence of microstructural abnormalities in the white matter of the brain in stroke patients, as well as the relationship between these microstructural abnormalities and changes in depressive symptoms over 6 months. Participants were 29 acute ischemic stroke patients and 37 healthy control subjects. Depressive symptoms were assessed in all subjects using the Hamilton Rating Scale for Depression and the Zung Self-rating Depression Scale. Whole brain voxel-based analysis was used to compare diffusion tensor imaging measures of Fractional Anisotropy (FA) between the groups. Six-month follow-up examinations were conducted. Patients showed significantly lower white matter FA values in the left and right anterior limbs of the internal capsule, and 6 months after the stroke they showed significantly increased FA values in these regions. We found a significant negative correlation between the increased ratio of the FA values and the change in depression scale scores at 6-month follow-up. Regional white matter damage may reflect abnormalities in neuroanatomical pathways related to the pathophysiology of depression.

Decision-making deficit of a patient with axonal damage after traumatic brain injury

Patients with traumatic brain injury (TBI) were reported to have difficulty making advantageous decisions, but the underlying deficits of the network of brain areas involved in this process were not directly examined. We report a patient with TBI who demonstrated problematic behavior in situations of risk and complexity after cerebral injury from a traffic accident. The Iowa gambling task (IGT) was used to reveal his deficits in the decision-making process. To examine underlying deficits of the network of brain areas, we examined T1-weighted structural MRI, diffusion tensor imaging (DTI) and Tc-ECD SPECT in this patient. The patient showed abnormality in IGT. DTI-MRI results showed a significant decrease in fractional anisotropy (FA) in the fasciculus between the brain stem and cortical regions via the thalamus. He showed significant decrease in gray matter volumes in the bilateral insular cortex, hypothalamus, and posterior cingulate cortex, possibly reflecting Wallerian degeneration secondary to the fasciculus abnormalities. SPECT showed significant blood flow decrease in the broad cortical areas including the ventromedial prefrontal cortex (VM). Our study showed that the patient had dysfunctional decision-making process. Microstructural abnormality in the fasciculus, likely from the traffic accident, caused reduced afferent feedback to the brain, resulting in less efficient decision-making. Our findings support the somatic-marker hypothesis (SMH), where somatic feedback to the brain influences the decision-making process.

Brain structural changes and neuropsychological impairments in male polydipsic schizophrenia

BACKGROUND

Polydipsia frequently occurs in schizophrenia patients. The excessive water loading in polydipsia occasionally induces a hyponatremic state and leads to water intoxication. Whether polydipsia in schizophrenic patients correlates with neuropsychological impairments or structural brain changes is not clear and remains controversial.

METHODS

Eight polydipsic schizophrenia patients, eight nonpolydipsic schizophrenia patients, and eight healthy controls were recruited. All subjects underwent magnetic resonance imaging (MRI) and neuropsychological testing. Structural abnormalities were analyzed using a voxel-based morphometry (VBM) approach, and patients' neuropsychological function was assessed using the Brief Assessment of Cognition in Schizophrenia, Japanese version (BACS-J).

RESULTS

No significant differences were found between the two patient groups with respect to the clinical characteristics. Compared with healthy controls, polydipsic patients showed widespread brain volume reduction and neuropsychological impairment. Furthermore, the left insula was significantly reduced in polydipsic patients compared with nonpolydipsic patients. These nonpolydipsic patients performed intermediate to the other two groups in the neuropsychological function test.

CONCLUSIONS

It is possible that polydipsia or the secondary hyponatremia might induce left insula volume reduction. Furthermore, this structural brain change may indirectly induce more severe neuropsychological impairments in polydipsic patients. Thus, we suggest that insula abnormalities might contribute to the pathophysiology of polydipsic patients.

Prolonged expression of Puma in cholinergic amacrine cells during the development of rat retina

During development of the nervous system, large numbers of neurons are overproduced and then eliminated by programmed cell death. Puma is a BH3-only protein that is reported to be involved in the initiation of developmental programmed cell death in rodent retinal neurons. The expression and cellular localization of Puma in retinal tissues during development are not, however, well known. Here the authors report the expression pattern of Puma during retinal development in the rat. During the period of programmed cell death in the retina, Puma was expressed in some members of each retinal neuron, including retinal ganglion cells, amacrine cells, bipolar cells, horizontal cells, and photoreceptor cells. Although the developmental programmed cell death of cholinergic amacrine cells is known to be independent of Puma, this protein was expressed in almost all their dendrites and somata of cholinergic amacrine cells at postnatal age 2 to 3 weeks, and it continued to be detected in cholinergic dendrites in the inner plexiform layer for up to 8 weeks after birth. These results suggest that Puma has some significant roles in retinal neurons after eye opening, especially that of cholinergic amacrine cells, in addition to programmed cell death of retinal neurons before eye opening.

Parkinsonism with multiple cysts in the bilateral striata

The present paper reports on a 68-year-old man with a 10-year history of parkinsonism who developed hallucinations and delusions after admission to an intensive care unit for the treatment of organophosphate intoxication. His initial diagnosis was delirium. On the basis of brain computed tomography findings and clinical symptoms, we diagnosed drug-induced psychosis in parkinsonism with multiple cysts in the bilateral striata.

Decreased binding of [11C]NNC112 and [11C]SCH23390 in patients with chronic schizophrenia

AIMS

Abnormality of cognitive function in schizophrenia has been suggested to be related to dopamine D1 receptor. However, the results of previous positron emission tomography (PET) studies of dopamine D1 receptor in schizophrenia were not consistent.

MAIN METHODS

In this study, six patients with schizophrenia in severe residual phase with chronic antipsychotic treatment and twelve healthy age-matched controls participated. Two different radioligands, [11C]NNC112 and [11C]SCH23390, for dopamine D1 receptor were used on the same subjects. Binding of the ligands was measured by PET, and statistical analysis was performed using one-way analysis of covariate (ANCOVA) with age as covariate.

KEY FINDINGS

Good correlations between binding potential values (BP(ND)) and age were observed in all regions of interest (ROIs) with both ligands. ANCOVA with age as covariate of BP(ND) values of all ROIs revealed that the patient group showed significantly lower BP(ND) value compared with the control group in both ligands.

SIGNIFICANCE

In patients with chronic schizophrenia in severe residual phase with chronic antipsychotic treatment, the binding potential values of both ligands were significantly lower in the striatum and cortical regions than those of healthy controls.

C38, equivalent to BM88, is developmentally expressed in maturing retinal neurons and enhances neuronal maturation

C38 antigen is specifically expressed in neuronal cells of the retina. The purpose of this study was to isolate C38 cDNA and determine its molecular functions. Sequence analysis of C38 cDNA revealed that C38 is equivalent to rat BM88, which has been reported to induce cell-cycle arrest and neuronal differentiation in Neuro2a cells. C38 and Ki67, a marker of proliferating cells, were not colocalized during retinal development. C38 was first detected in the retinal ganglion cells at embryonic day 16, much later than the expression of doublecortin, a marker of immature neurons. Although all the horizontal cells were post-mitotic at this stage, C38 was not detected in horizontal cells until the postnatal period. In addition, C38 over-expression did not induce neuronal differentiation or cell-cycle arrest of pluripotent P19 embryonal carcinoma cells. Instead, C38 promoted maturation during neuronal differentiation of P19 embryonal carcinoma cells by down-regulating Oct-3, a pluripotent cell marker and enhancing the expressions of positive regulators of neurogenesis. In conclusion, during retinal development, C38 is first expressed in post-mitotic retinal neurons and is up-regulated during their maturation. C38 does not induce neuronal competence in pluripotent cells, but does promote maturation in already committed neuronal cells.

Reduced serotonin transporter binding in the insular cortex in patients with obsessive-compulsive disorder: a [11C]DASB PET study

The serotonin transporter (5-HTT) and other markers of the serotonergic system have been of interest in the pathophysiology of obsessive-compulsive disorder (OCD). Previous studies using single photon emission computed tomography (SPECT) with [(123)I]beta-CIT or positron emission tomography (PET) with [(11)C]McN5652 have not shown consistent findings about 5-HTT in OCD patients. The aim of the present study was to investigate 5-HTT binding using [(11)C]DASB, which has higher selectivity or specific binding-to-nonspecific binding ratios for 5-HTT compared to the aforementioned radioligands. Four drug-naive and 6 drug-free patients with OCD who were free of comorbid depression and 18 gender and age-matched healthy subjects underwent PET scans with [(11)C]DASB. The severity of OCD was assessed by Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) (mean+/-SD: 22+/-7.6, range: 7-32). The binding potential (BP(ND)) of [(11)C]DASB was calculated using a two-parameter multilinear reference tissue model (MRTM2). The parametric images of BP(ND) were analyzed using a statistical parametric mapping system. Significant reductions of BP(ND) were observed in the right posterior and left anterior insular cortices in patients with OCD compared to controls. Region-of-interest analysis has also confirmed significant reduction of BP(ND) in the insular cortex. Although significantly reduced BP(ND) in the orbitofrontal cortex was also observed in patients with OCD compared to controls, this finding should be considered with caution because of the very low 5-HTT binding in the region. On the other hand, no significant correlation was observed between the Y-BOCS score and BP(ND). The change in [(11)C]DASB binding in the insular cortex suggests that dysfunction of the serotonergic system in the limbic area might be involved in the pathophysiology of OCD.

Abnormalities of the uncinate fasciculus and posterior cingulate fasciculus in mild cognitive impairment and early Alzheimer's disease: a diffusion tensor tractography study

Mild cognitive impairment (MCI) is considered the transitional stage between normal cognition and dementia. The aim of this study was to use tractography based analysis to elucidate alterations in subjects with MCI compared with subjects with early Alzheimer's disease (AD) and controls. Seventeen subjects with early AD, 16 with MCI and 16 controls underwent magnetic resonance diffusion tensor imaging (DTI) and neuropsychological assessment. Diffusion tensor tractographies were computed and fiber-tract maps were generated using "dTV II" DTI software. We measured mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the uncinate fasciculus (UNC), posterior cingulate fasciculus (PCF) and corticospinal tract (CST). There were statistically significant differences in the FA and ADC values of the UNC and PCF between subjects with early AD and controls. Subjects with MCI exhibited significantly lower FA values on both sides of the PCF relative to controls. However, there were no significant differences between subjects with early AD and MCI for any measurement. Our results suggest that alterations in the PCF precede the onset of dementia.

Acetylcholine induces Ca2+ signaling in chicken retinal pigmented epithelial cells during dedifferentiation

Retinal pigmented epithelial cells exchange their cellular phenotypes into lens cells and neurons, via depigmented and non-epithelial-shaped dedifferentiated intermediates. Because these dedifferentiated cells can either revert to pigmented epithelial cells or transdifferentiate into lens cells and/or neurons, they are recognized as candidates for lens and retinal cell regeneration. The purpose of the present study was to elucidate the signal transduction pathways between chicken retinal pigmented epithelial cells and their dedifferentiated intermediates. We monitored intracellular Ca(2+) concentrations using Fluo-4-based Ca(2+) optical imaging and focused on cellular responses to the neurotransmitter acetylcholine. Muscarinic Ca(2+) mobilization was observed both in retinal pigmented epithelial cells and in dedifferentiated cells, and was inhibited by atropine. The muscarine-dependent acetylcholine response depended on Ca(2+) release from intracellular Ca(2+) stores, which was completely blocked by thapsigargin. In contrast, the nicotine-dependent acetylcholine response that led to Ca(2+) influx through L-type Ca(2+) channels was inhibited by alpha-bungarotoxin and attenuated by nifedipine, and it was detected only in the dedifferentiated intermediates. Application of (S)-(-)-BayK8644 elevated intracellular Ca(2+) both in retinal pigmented epithelial cells and in dedifferentiated intermediates; however, the nicotinic response was not observed in pigmented epithelial cells. Another L-type Ca(2+) channel blocker, diltiazem, also blocked the nicotine-dependent acetylcholine response in dedifferentiated cells and maintained the epithelial-like morphology of retinal pigmented epithelial cells. Our results indicate that an alternative acetylcholine signaling pathway is used during the dedifferentiation process of retinal pigmented epithelial cells.

Early downregulation of IGF-I decides the fate of rat retinal ganglion cells after optic nerve injury

Retinal ganglion cells (RGCs) die by apoptosis after optic nerve injury. A number of reports have separately shown changes in pro-apoptotic proteins such as the Bcl-2 family members following optic nerve injury. However, induction time of these apoptotic signals has not been identified due to different treatments of the optic nerve, and insufficient time intervals for measurements. Therefore, the stream of cell death signals is not well understood. In the present study, we systematically reinvestigated a detailed time course of these cell death/survival signals in the rat retina after optic nerve crush, to determine the signal cascade leading to RGC apoptosis. The most conspicuous changes detected in the retina were the rapid inactivation of phospho-Akt and phospho-Bad proteins 2-3 days after optic nerve damage, and the subsequent gradual activation of Bax protein and caspase-3 activity accompanied by cell loss of RGCs 6 days after nerve injury. Cellular localization of these molecular changes was limited to RGCs. Furthermore, amount of insulin-like growth factor-I (IGF-I), an activator of the phosphatidyl inositol-3-kinase (PI3K)/Akt system, was initially decreased from RGCs 1-2 days just prior to the inactivation of phospho-Akt by optic nerve crush. Conversely, supplementation with IGF-I into the rat retina induced upregulation of phospho-Akt expression and cell survival of RGCs both in vitro and in vivo. Thus, injury to the optic nerve might induce early changes in cellular homeostasis with a plausible loss of trophic support for injured RGCs. Actually, IGF-I drastically enhanced neurite outgrowth from adult rat RGCs via a wortmannin-dependent mechanism in a retinal explant culture. Our data strongly indicate that IGF-I is a key molecule that induces RGC apoptosis or RGC survival and regeneration in the retina during the early stage of optic nerve injury.

Quantification of PERF 15 mRNA in tissue sections from rat testes

We previously conducted basic research to quantify in situ hybridization (ISH) signals in rat testes. In this experimental model, we selected ribosomal RNA (rRNA) as the hybridizable RNA in paraffin sections, since it allowed us to easily analyze ISH signals expressed with digoxygenin (DIG)-labeled probes quantitatively through “posterization” of the images. We applied this method to analyze the quantification of transcript, PERF 15 mRNA. PERF 15 is expressed specifically in the testes and localized in the rigid cytoskeletal structure of the sperm head, and has been considered to be involved in the apoptotic process of spermatogenic cells. Quantification of the signals may help to clarify the detailed function of PERF 15. We further analyzed the signals concomitant with a confocal laser scanning microscope. The peak of PERF 15 mRNA expression was found in diplotene spermatocytes, and the amount of PERF 15 mRNA was greatest in late pachytene and diplotene spermatocytes and early spermatids, followed by early pachytene spermatocytes, and then late spermatids. PERF 15 may be involved in the events leading to meiotic division, in which apoptosis is also involved. The present study may help to determine the concentration of mRNA in tissue sections.

A dose-finding study of duloxetine based on serotonin transporter occupancy

RATIONALE

Positron emission tomography (PET) has been utilized for determining the dosage of antipsychotic drugs. To evaluate the dosage of antidepressants such as selective serotonin reuptake inhibitors, serotonin transporter occupancy (5-HTT) is also a useful index.

OBJECTIVES

We investigated the degree of 5-HTT occupancy with different doses of the antidepressant duloxetine and the time-course of 5-HTT occupancy using PET.

METHODS

PET scans with [11C]DASB were performed before and after a single administration of duloxetine (5-60 mg), and three consecutive scans were performed after a single dose or repeated doses of 60 mg of duloxetine.

RESULTS

5-HTT occupancies by duloxetine were increased by 35.3 to 86.5% with dose and plasma concentration increments. The ED50 value of 5-HTT occupancy was 7.9 mg for dose and 3.7 ng/ml for plasma concentration. In the time-course of 5-HTT occupancy, mean occupancies were 81.8% at 6 h, 71.9% at 25 h, and 44.9% at 53 h after a single administration, and 84.3% at 6 h, 71.9% at 49 h, and 47.1% at 78 h after repeated administrations.

CONCLUSIONS

Based on 5-HTT occupancy, 40 mg and more of duloxetine was needed to attain 80% occupancy, and 60 mg of duloxetine could maintain a high level of 5-HTT occupancy with a once-a-day administration schedule.

Quantitative analyses of 18F-FEDAA1106 binding to peripheral benzodiazepine receptors in living human brain

N-(5-Fluoro-2-phenoxyphenyl)-N-(2-(18)F-fluoroethyl-5-methoxybenzyl)acetamide ((18)F-FEDAA1106) is a potential PET ligand with highly selective and specific binding to peripheral benzodiazepine receptor (PBR). It has been reported that the regional density of PBR in the brain is increased in several neurodegenerative and psychiatric disorders. Thus, a reliable tracer method for evaluating PBR would be of use clinically and for research. To our knowledge, this is the first study to investigate the (18)F-FEDAA1106 binding to PBR in living human brain by PET. We also aimed to evaluate various analytic methods to quantify the density of PBR.

METHODS

PET studies with (18)F-FEDAA1106 were performed on 7 healthy men. Volumes of interest (VOIs) were drawn on PET images. In each VOI, binding potential (BP) was calculated by nonlinear least-squares (NLS) fitting based on the 2-tissue compartment model, and the distribution volume (DV) was also estimated by NLS, Logan plot, and multilinear analysis (MA) methods. To estimate errors in calculation of BP and DV, simulation studies were also performed.

RESULTS

The DVs estimated with each of the methods were significantly correlated. There was also significant correlation between BP with NLS and DV with NLS, Logan plot, or MA. But the interindividual differences in the distribution volume of the free and nonspecific binding compartment (K(1)/k(2)) were relatively large. In a simulation study, variation of the DV estimated by Logan plot was relatively small, but it was underestimated as the noise increased. By MA, the bias of DV was smaller, but the variation of DV was larger than by Logan plot. Within a 3% noise level, there was almost no difference between Logan plot and MA in both bias and variation. DVs estimated by both Logan plot and MA were underestimated by 10%-20%. Although the variation of DV was larger by NLS than by Logan plot, it was small enough in the noise level of VOI analysis, and the bias of DV was 0%-2%.

CONCLUSION

The simulation studies indicated that NLS is a suitable method for the estimation of (18)F-FEDAA1106 binding to PBRs.

Retinal stem/progenitor properties of iris pigment epithelial cells

Neural stem cells/progenitors that give rise to neurons and glia have been identified in different regions of the brain, including the embryonic retina and ciliary epithelium of the adult eye. Here, we first demonstrate the characterization of neural stem/progenitors in postnatal iris pigment epithelial (IPE) cells. Pure isolated IPE cells could form spheres that contained cells expressing retinal progenitor markers in non-adherent culture. The spheres grew by cell proliferation, as indicated by bromodeoxyuridine incorporation. When attached to laminin, the spheres forming IPE derived cells were able to exhibit neural phenotypes, including retinal-specific neurons. When co-cultured with embryonic retinal cells, or grafted into embryonic retina in vivo, the IPE cells could also display the phenotypes of photoreceptor neurons and Muller glia. Our results suggest that the IPE derived cells have retinal stem/progenitor properties and neurogenic potential without gene transfer, thereby providing a novel potential source for both basic stem cell biology and therapeutic applications for retinal diseases.

Intracellular delivery of proteins into mammalian living cells by polyethylenimine-cationization

In the post-genomic era, there is pressing need for development of protein manipulation methodology to analyze functions of proteins in living cells. For this purpose, techniques to deliver functional proteins into living cells are currently being evaluated as alternative approaches to the introduction of transcriptionally active DNA. Here, we describe a novel method for efficient protein transduction into living cells in which a protein is simply cationized with polyethylenimine (PEI) by limited chemical conjugation. PEI-cationized proteins appear to adhere to the cell surface by ionic charge interaction and then internalize into cells in a receptor- and transporter-independent fashion. Since PEI is an organic macromolecule with a high cationic-charge density, limited coupling with PEI results in endowment of sufficient cationic charge to proteins without causing serious decline in their fundamental functions. A number of PEI-cationized proteins, such as ribonuclease (RNase), green fluorescent protein (GFP) and immunoglobulin (IgG), efficiently entered cells and functioned in the cytosol. Our results suggest that protein cationization techniques using PEI will be useful for the development of protein transduction technology.

Iris movement mediates vascular apoptosis during rat pupillary membrane regression

In the course of mammalian lens development, a transient capillary meshwork known as the pupillary membrane (PM) forms, which is located at the pupil area; the PM nourishes the anterior surface of the lens and then regresses to make the optical path clear. Although the involvement of apoptotic process has been reported in the PM regression, the initiating factor remains unknown. We initially found that regression of the PM coincided with the development of iris motility, and iris movement caused cessation and resumption of blood flow within the PM. Therefore, we investigated whether the development of the iris's ability to constrict and dilate functions as an essential signal that induces apoptosis in the PM. Continuous inhibition of iris movement with mydriatic agents from postnatal day 7 to day 12 suppressed apoptosis of the PM and migration of macrophage toward the PM, and resulted in the persistence of PM in rats. The distribution of apoptotic cells in the regressing PM was diffuse and showed no apparent localization. These results indicated that iris movement induced regression of the PM by changing the blood flow within it. This study suggests the importance of the physiological interactions between tissues-in this case, the iris and the PM-as a signal to advance vascular regression during organ development, and defines a novel function of the iris during ocular development in addition to the well-known function, that is, optimization of light transmission into the eye.

JNK inhibitory kinase is up-regulated in retinal ganglion cells after axotomy and enhances BimEL expression level in neuronal cells

Optic nerve transection results in retinal ganglion cell (RGC) death in adult mammals, after the alteration of gene expression of RGCs. To elucidate the molecular mechanism by which axotomy induces RGC death, we isolated the molecules up-regulated after optic nerve transection. One of these, axotomy-related [corrected] gene (ARG)357, an 898-amino-acid [corrected] protein containing a complete serine-threonine kinase domain, was isolated from a subtraction library of the rat retina. The sequence showed that this gene was a rat homolog of human c-Jun N-terminal kinase (JNK) inhibitory kinase and so belonged to the germinal center kinase-VIII subfamily of Sterile20s protein kinase. We designated ARG357 as rat JNK inhibitory kinase (JIK). Rat JIK was expressed ubiquitously in various tissues and was highly expressed in the retina, with selective expression in RGCs. After axotomy, BimEL and Hrk, which are BH3-only proteins, and rat JIK were up-regulated in RGCs. Overexpression of rat JIK in neuronal cells up-regulated the expression of BimEL, but not that of Hrk. These results indicate that JIK may contribute to axotomy-induced RGC death by up-regulating the expression of BH3-only protein.

Quantification of in situ hybridization signals in rat testes

We performed basic research into quantifying in situ hybridization (ISH) signals in rat testis, a suitable organ for the quantification because germ cells undergo synchronized development and show stage-specific gene expression. In this model experiment, rRNA was selected as the hybridizable RNA in paraffin sections. Specimens fixed with Bouin's fixative and hybridized with digoxygenin-labeled probes could easily be analyzed quantitatively through "posterization" of the images. The amount of rRNA hybridized with the probe was greatest in early primary spermatocytes, followed by pachytene primary spermatocytes, then diplotene spermatocytes, and finally by secondary spermatocytes and spermatids. The amounts reached low levels in metaphase, anaphase, and telophase of meiotic division and early step 1 spermatids, and then slightly increased during spermiogenesis. ISH rRNA staining was a useful parameter for evaluation of the quantitative analysis of mRNA and the levels of hybridizable RNA in tissue sections.

Possible mechanism of polycation liposome (PCL)-mediated gene transfer

A novel gene transfer system utilizing polycation liposomes (PCLs), obtained by modifying liposomes with cetyl polyethylenimine (PEI), was previously developed (Gene Ther. 7 (2002) 1148). PCLs show notable transfection efficiency with low cytotoxicity. However, the mechanism of PCL-mediated gene transfer is still unclear. In this study, we examined the intracellular trafficking of PCL-DNA complexes by using HT1080 cells, fluorescent probe-labeled materials, and confocal laser scan microscopy. We found that the PCL-DNA complexes were taken up into cells by the endosomal pathway, since both cellular uptake of the complex and gene expression were blocked by wortmannin, an inhibitor of this pathway. We also observed that the plasmid DNA and cetyl PEI complex became detached from the PCL lipids and was preferentially transferred into the nucleus in the form of the complex, whereas the PCL lipids remained in the cytoplasmic area, possibly in the endosomes. In fact, nigericin, which dissipates the pH gradient across the endosomal membrane, inhibited the detachment of lipids from the PCL-DNA complex and subsequent gene expression. Taken together, our data indicate the following mechanism for gene transfer by PCLs: PCLs effectively transfer DNA to endosomes and release cetyl PEI-DNA complexes into the cytosol. Furthermore, cetyl PEI also contributes to gene entry into the nucleus.

A case of general paresis showing marked treatment-associated improvement of cerebellar blood flow by quantitative imaging analysis

We describe a patient with general paresis who developed progressive dementia and a cerebellar syndrome including wide-based gait, slurred speech, and intention tremor. Quantitative analysis by means of a Patlak plot of single-photon emission computed tomography (SPECT) with 99mTc-ethyl cysteinate dimer showed generally low blood flow in the cerebrum and the cerebellum. After antisyphilitic therapy, blood flow in the brain, especially in the cerebellum, improved noticeably, as did the cognitive disorder and the cerebellar syndrome.

Up-regulation of Hrk, a regulator of cell death, in retinal ganglion cells of axotomized rat retina

Hrk, a regulator of cell death, belongs to the family of pro-apoptotic BH3-only proteins and is known to induce apoptosis in nerve tissue. We examined Hrk gene expression to clarify the role of BH3-only proteins in apoptosis of retinal ganglion cells (RGCs) after optic nerve transection in the adult rat. Reverse transcription-polymerase chain reaction showed that Hrk was up-regulated in retina from 12 h after axotomy, and continued to be elevated for 1 week. In situ hybridization histochemistry revealed that Hrk was expressed in a sub-population of axotomized RGCs. These results suggest that Hrk is involved in the induction of apoptosis in RGCs after optic nerve transection.

The influence of the timing of administration of thiopentone sodium on nitric oxide-mediated neurotoxicity in vitro

Thiopentone sodium is a highly useful pharmacological agent that provides a neuroprotection against cerebral ischaemia. Since not all patients can receive thiopentone sodium before cerebral ischaemia occurs, we investigated the influence of timing of thiopentone sodium administration on the neurotoxicity induced by nitric oxide (NO) using Shibuta's established model of primary brain cultures. Cortical neurones prepared from 16-day gestational rat foetuses were used after 13-14 days in culture. The cells were exposed to an NO-donor, NOC-5 at 30 microM. Thiopentone sodium administered at 30 and 10 min before or 5, 10 and 15 min after exposure to NOC-5, but not thereafter, significantly attenuated NO-induced neurotoxicity compared with controls. The survival rate of the neurones in which thiopentone sodium was administered at 15 min after exposure to NOC-5 was 55.7+/-2.4%, compared to a 10.0+/-1.6% survival rate in neurones when thiopentone sodium was administered at 30 min after exposure to NOC-5. These findings demonstrate that thiopentone sodium, which protects cerebral cortical neurones against NO-mediated cytotoxicity, should be given as soon as possible in case ischaemic or hypoxic neuronal damage is predicted.

Survival of axotomized retinal ganglion cells in peripheral nerve-grafted ferrets

PURPOSE

Peripheral nerve (PN) grafting to the optic nerve stump stimulates not only axonal regeneration of the axotomized retinal ganglion cells (RGCs) into the grafted PN but also their survival. The purpose of the present study was to determine the number, distribution, and soma diameter of only surviving RGCs without regenerated axons and surviving RGCs with regenerated axons in PN-grafted mammals.

METHODS

A segment of PN was grafted to the optic nerve stump of adult ferrets. Two months after the PN grafting, surviving RGCs with regenerated axons were retrogradely labeled with granular blue (GB) and stained with RGC-specific antibody C38. Surviving RGCs without regenerated axons were identified as C38-positive cells without GB labeling.

RESULTS

Twenty-one percent of RGCs survived axotomy after PN grafting in the area centralis (AC), whereas 47% survived in the peripheral retina. Twenty-six percent of surviving RGCs in the AC exhibited axonal regeneration, which was higher than that in the peripheral retina. Soma diameter histograms revealed that RGCs with regenerated axons showing both GB and C38 positivity were in the large soma diameter ranges. In contrast, the soma diameter distribution of surviving RGCs that did not have regenerated axons showed a peak in the smaller soma diameter ranges.

CONCLUSIONS

The present data suggest that PN grafting promotes survival of axotomized RGCs more effectively in the peripheral retina than in the AC. Among surviving RGCs, the larger cells exhibited axonal regeneration into the grafted PN, whereas the axons of smaller cells did not to regenerate in either the AC or the peripheral retina.