Gliofibroma originating from temporoparietal hamartoma-like lesions

Clinical and neuropathologic observations are reported of a 16-year-old girl with a right temporoparietal tumor. The histologic picture revealed cortical areas with a peculiar growth of neurons, glia or tumor cells, and strands of collagen following the pattern of the cortical architecture. In this area of hamartoma-like cortex a large tumor nodule was found with anaplastic cells in fibrous stroma exhibiting partially positive GFAP reaction. The picture closely resembles the features of a tumor described in 1978 by Friede in the medulla oblongata of a 3-year and 9-month-old girl. A comparison of histology and ultrastructure of both tumors is followed by discussion of the origin of this peculiar type of tumor, focussing on the existence of unusually pluripotent cells that may develop into glial and mesenchymal cells.     

Hemangioblastoma originating from the right cerebellopontine angle

The morbidity of hemangioblastoma in the supratentorial region is very low, and is seldom found in the area of the cerebellopontine angle, so it is easily misdiagnosis before surgery. We report and discuss a case of hemangioblastoma originating at the right cerebellopontine angle in a 42-year-old female patient.     

Primary cystic germinoma originating from the midbrain

A primary intracranial germinoma that involves the midbrain is rare. We describe an unusual case of primary cystic germinoma originating from the midbrain. A 29-year-old man presented with diplopia, and his MRI showed a cystic, ring-like enhanced lesion in the thalamo–mesencephalic junction. Open biopsy was performed and the diagnosis of germinoma was based upon the histopathological findings. Following chemotherapy and radiotherapy, the symptoms improved and the tumor disappeared. We propose that primary intracranial germinoma should be included in the differential diagnosis of midbrain tumors, because early diagnosis and appropriate treatment for midbrain germinoma improves clinical outcome.     

Modulation of the somatosensory evoked potentials by the input information originating from the gastrocnemius and sural nerves in the dog

Input-output characteristics of the somatosensory system were studied in the dog. Somatosensory evoked potentials were recorded from the scalp at stimulations of the sural and gastrocnemius nerves. There was a sigmoid relationship between the stimulus strength and the amplitude of the sural nerve action potential, which was best described by a logistic equation. The early waves (P1, N1) increased especially at low threshold stimulations of the sural nerve; then they remained either unchanged or decreased at high threshold stimulations within the Group II and III ranges. The late waves (P2, N2) especially increased at high threshold Group II stimulations of the sural nerve, and increased further at strong stimuli. Similar changes were observed at stimulations of the gastrocnemius nerves. The attenuation of the early waves was explained by "gating" mechanisms acting from the sensorimotor cortex onto the sensory relay nuclei. The increase of the late waves at especially high threshold Group II and III stimulations was accounted for by the multisynaptic diffuse projection from the reticular formation and/or the nonspecific thalamic nuclei to the somatosensory cortex. In a three weeks old pup, stimulation of the gastrocnemius nerves evoked somatosensory responses with similar morphology observed in adult dogs, but the latencies of the evoked potential components were relatively long, presumably as a result of the uncompleted myelination in the somatosensory afferent system.     

Neural activity originating from a neuroma in the baboon

Single nerve fiber recordings were obtained from traumatically induced neuromas of the superficial radial nerve in baboons 1-7 months after injury. Eight to 18% of the fibers had spontaneous activity, and 67% of these were unmyelinated. Myelinated as well as unmyelinated fibers responded to mechanical stimulation of the neuroma whereas no fibers responded to similar stimulation of the normal nerve. Apparent crosstalk of action potential activity between fibers at the neuroma was observed which could be due to electrical coupling, though retrograde sprouting is another possible explanation. These abnormalities in neural activity originating from a neuroma in the primate are qualitatively similar to those noted in other species and may provide an explanation for certain abnormal sensory phenomena associated with peripheral nerve injury.     

Surgical treatment of hypermotor seizures originating from the temporal lobe

PurposeTo describe the characteristics of electroclinical manifestations in patients with hypermotor seizures (HMSs) originating from the temporal lobe.MethodsWe retrospectively reviewed the data of patients who underwent surgical treatments for seizure to identify patients with HMSs of temporal origin. We systematically reviewed patient seizure histories, imaging reports, video-EEG monitoring data, operative records and pathological findings.ResultsEight of the 9 patients reported auras. The ictal behavior included marked agitation in 5 patients and mild agitation in 4 patients. All of the 9 patients exhibited stiffness or dystonia of the upper limb or contralateral limbs during ictus. Seven of the 9 patients completed intracranial recording and at least 3 seizures were recorded for each patient. The intracranial recordings showed ictal activity originating from mesial temporal lobe in 6 patients and the lateral temporal lobe in 1 patient. The time interval of ictal propagation from the temporal to frontal lobe was 15.0 ± 8.3 s. While the time interval from EEG origination to the beginning of hypermotor behavior was 21.0 ± 8.1 s. Brain MRIs revealed hippocampal sclerosis in 3, neoplastic lesion in 1, and normal images in the remaining 5 patients. Patients were followed for 1–5 years after the anterior temporal lobectomy; 7 patients remained seizure-free throughout follow-up.ConclusionSome HMSs can originate from the temporal lobe. In carefully selected patients, surgical resection may lead to good outcomes.     

Fine structure of collateral axons originating from feline spinocervical tract neurons

In adult cats, 7 spinocervical tract neurones were intracellularly labelled with horseradish peroxidase and ultrastructural properties of collateral axons of 3 of them were examined. The terminations of collateral axons formed boutons which made synaptic associations predominantly with the somata and proximal dendrites of dorsal horn neurones. Collateral axons of one spinocervical tract neurone formed synaptic associations with a cell which projected via the dorsal columns.     

Arteriovenous fistula originating from proximal part of the anterior cerebral artery

Intracerebral arteriovenous fistulas of the brain may be misdiagnosed as arteriovenous malformation. There are only a few reports in the literature about this concept and to the best of our knowledge this is the first case arising from the proximal part of the anterior cerebral artery in association with an aneurysm that ruptured. A 64-year-old man presented with subarachnoid hemorrhage. The patient was neurologically intact. Cerebral angiography and magnetic resonance imaging of the patient revealed a small arteriovenous malformation of the brain involving the region of gyrus rectus and the posteromedial aspect of the orbitofrontal gyrus in addition to an aneurysmal dilatation within the malformation. An arteriovenous fistula arising from the junction of the A1 and A2 segments of the right anterior cerebral artery connected to a vein that has tributaries spreading over the fronto-orbital gyrus and gyrus rectus, were observed during surgery. The patient was successfully treated with clip ligatation of the fistula. Intracerebral arteriovenous fistulas are rare lesions. They may easily be misdiagnosed as arteriovenous malformations. There preoperative consideration in the differential diagnosis can help to decide the most appropriate treatment option.     

A very large Schwannoma originating from the median nerve in carpal tunnel

Schwannomas are common benign nerve tumors occurring in the peripheral nerves. A very large schwannoma of more than 5 years duration, originating from the median nerve in the carpal tunnel in a 38-year-old woman, is reported. There was a painful mass, 60 mm in length and 42 mm in diameter, on the palm without signs of sensory disturbance or atrophy on the thenar muscles. Surgical removal was performed under high-power magnification by separating the sensory and motor fascicles from the tumor. Histological examination resulted in a Schwannoma. At 4-year follow-up, the patient was asymptomatic with excellent relief of symptoms. The tumor did not recur. Although cases have been reported in the literature, this is one of the largest ever described without any neurologic deficit.     

Neurotoxic potential of polystyrene nanoplastics in primary cells originating from mouse brain

Polystyrene (PS) and chemically modified compounds in the PS family have long been used in commercial and industrial fields. However, it is poorly understood whether nanoscale-PS microplastic or PS nanoplastic exposure leads to perturbations in fundamental cellular functions, such as proliferation, differentiation, and apoptosis. Herein, we cultured three types of primary cells, including mouse embryonic fibroblasts (MEFs), mixed neuronal cells isolated from embryonic cortex, and cortical astrocytes, and investigated the effects of their exposure to PS nanoplastics with a 100 nm diameter. Although PS nanoplastic exposure did not affect the viability of MEFs or astrocytes, it significantly reduced the viability of mixed neuronal cells. Consistent with the observed effect on cellular viability, levels of the apoptosis marker, cleaved caspase-3, were elevated exclusively in mixed neuronal cells. To investigate whether cells uptake PS nanoplastics into the cytoplasm, we exposed MEFs and neurons to fluorescent PS latex beads and monitored fluorescence over time. We found that PS nanoplastics were deposited and accumulated in the cytoplasm in a concentration-dependent manner. Although astrocytes were not apoptotic upon exposure to PS nanoplastics, they underwent reactive astrocytosis, with increased levels of lipocalin-2 and proinflammatory cytokines. Therefore, our findings suggested that the vulnerability of cells to the deposition and accumulation of PS nanoplastics in the cytoplasm was dependent on cell type. Furthermore, based on our data from primary cells originating from mouse brains, we suggest that reactive astrocytosis may contribute to the neuronal apoptosis seen in defective neurons with PS nanoplastics accumulated in the cell body.