Somatic action potentials (AP) of cortical pyramidal neurons have characteristically high onset-rapidness. The onset of the AP waveform is an indirect measure for the ability of a neuron to respond to temporally fast-changing stimuli. Theoretical studies on the pyramidal neuron response usually involves a canonical Hodgkin-Huxley (HH) type ion channel gating model, which assumes statistically independent gating of each individual channel. However, cooperative activity of ion channels are observed for various cell types, meaning that the activity (e.g. opening) of one channel triggers the activity (e.g. opening) of a certain fraction of its neighbors and hence, these groups of channels behave as a unit. In this study, we describe a multi-compartmental conductance-based model with cooperatively gating voltage-gated Na channels in the axon initial segment. Our model successfully reproduced the somatic sharp AP onsets of cortical pyramidal neurons. The onset latencies from the initiation site to the soma and the conduction velocities were also in agreement with the previous experimental studies.
Verification of the performance of the sanitation procedure is as important as the actual application. The methods that are going to be used for such verification needs to be user friendly and rapid resulting to apply the corrective actions promptly. Additionally, these methods should also be reliable besides their fast resulting. ATP bioluminescence method is recommended to be a solution for such procedures for many years. In this present study, our aim was to evaluate the performance of ATP bioluminescence method by comparison with golden standard classical cultural method. For this we performed parallel testing on surfaces which were experimentally contaminated with different types of microorganisms. The results showed that ATP bioluminescence gives more reliable results in surfaces which do not have any physical dirt and are contaminated with high level of microorganisms. The most reliable results were obtained from Salmonella contaminated surfaces.
Pituitary tumors are the most common form of intracranial neoplasms. However, clinically relevant pituitary tumors presenting with disturbances of hormonal secretion or mass effect are rare and they only represent about 10 % of all surgically resected intracranial neoplasms. Prolactinomas are the most common types of pituitary adenomas. Generally, hormonal expression patterns provided by immunohistochemistry (IHC) studies are correlated with the clinical features and endocrine activity of the patients. Nonetheless, exceptions occur where the immunocytochemical staining is not concordant with the clinical picture. Pituitary adenomas presenting with apoplexy are well known. However, pituitary adenomas causing cerebral stroke and resulting in hemiplegia are unusual. Here, we report an unusual case of prolactinoma with cerebral stroke and sparse prolactin (PRL) expression. A 25-year-old woman complaining of amenorrhea, dysphasia, and left hemiplegia presented with serum PRL level in excess of 4,700 ng/ml. Pre-operational radiology images revealed a giant macroadenoma and a thalamic infarct due to carotid compression. Transcranial surgery was performed. IHC study of the adenoma revealed no hormonal expression other than sparse PRL immunoreactivity. Therefore, a sparsely granulated PRL cell adenoma was diagnosed. The patient is still under follow-up with continuing cabergoline treatment.
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