Extracellular recording is a key technology to study many types of brain functions. However the amplitudes of extracellular spikes are typically about 100 muV and should be picked up and amplified specially, then recorded and analyzed online. Most of the equipment for extracellular recording are either very expensive, or too large for recording in the brains of freely moving small animals. In this paper we developed a practical multi-electrode recording system based on virtual testing technology. The system includes microelectrode amplifier, analog input device NI4472 with 24-bit resolution, and data processing software SPKrec. The features of the hardware are low noise, high input impedance, a total gain of 2 000, and large dynamic range. The software developed in LabVIEW is capable of online analysis, data recording, spike detection, fire rate histograms, etc. The system functions have been verified in extracellular recording in the olfactory bulb of Gekko gecko. The result indicates that the system with performance comparable to that of commercial products meets the requirements of recording experiments.
Animals ; Brain ; physiology ; Lizards ; physiology ; Microelectrodes ; Olfactory Bulb ; physiology

Enterocolitis, Necrotizing ; metabolism ; pathology ; Female ; Humans ; Immunohistochemistry ; Infant, Newborn ; Intestinal Mucosa ; metabolism ; pathology ; Male ; Platelet Activating Factor ; metabolism

Objective To study the expressions of foliate binding protein 1(Folbp1),Wnt and ?-catenin genes on the heart of offspring during the development of embryo,whose mother was deficient of folic acid.Methods Control group involving 18 rats and study group involving 18 rats were choosen from the total 36 adult female SD rats randomly copulate with the male normal rats after feeding different fodder for 2 weeks.The heart of the 13.5,17.5 days embryos and the newborns were obtained.The expressions of Folbp1,Wnt and ?-catenin genes mRNA at the 3 periods were evaluated by RT-PCR.Results The expressions of Folbp1,Wnt and ?-catenin genes mRNA of the study group were significantly weaker than those of the control group in heart of the 13.5,17.5 days embryos and the newborns(all P

Objective To clarify the understanding of types of laboratories and manufacturers for GB 9706.1-2020 Medical electrical equipment-Part 1:General requirements for basic safety and essential performance by laboratory proficiency testing for creepage distance and electrical clearance test.Methods An operation guide was formed according to the testing program in GB 9706.1-2020,and the homogeneity and stability of the samples were evaluated according to CNAS-GL003:2018 Guidance on Evaluating the Homogenneity and Stability of Samples Used for Proficiency Testing.Robust statistic methods were used to assess the quantitative parameters of the test results of the participating laboratories according to the requirements in GB/T 28043-2019 Statistical methods for use in proficiency testing by interlaboratory comparison;the results reported by the expert laboratories were used as the specified values of the qualitative parameters.SPSS 25.0 statistical software was used for data analysis.Results All the results of the crreepage distance and electrical clearance tests met the requirements for homogeneity and stability.Of the 46 laboratories involved in,37 ones did have comprehensive satisfactory determinations while the remained 9 ones not.Conclusion Some laboratories don't behave well in understanding the standard,which have to be reformed accordingly to enhance their proficiencies.[Chinese Medical Equipment Journal,2024,45(10):54-59]

OBJECTIVETo examine cytokeratin 18(CK18) and it's gene in jaw odontogenic keratocyst (OKC) epithelial lining.

METHODSThe epithelial linings of 32 cases were subject to monoclonal antibody immunohistochemical staining for CK18, CK8 and CK19. RT-PCR and in situ hybridization for CK18 mRNA were conducted in 12 of 32 cases in keratocyst epithelial cell linings.

RESULTSIn 17 cases, CK18 were observed in keratinized surface layers, though weakly positive. In 27 cases, CK18 were positive in the granular cell layers. CK18 were also positive in the spinous cell layers in 14 cases. In all cases, CK18 was negative in basal cell layers. By RT-PCR, 4 cases expressed CK18 strongly, 8 cases weakly. By in situ hybridization, 8 cases expressed CK18 mRNA positively in both spinous and granular cell layers, and 4 cases positively in basal and keratinized cell layers. CK8 were expressed in basal cell layers of keratocyst epithelial linings. In 23 cases, CK19 were expressed in surface cell layers of keratocyst epithelial linings.

CONCLUSIONThe expression of CK18 in keratocyst epithelial linings transfers from basal cell layer to spinous layer. The expression of CK18 immunohistochemical staining and CK18 mRNA in situ hybridization are different, which shows CK18 might be related to proliferation of OKC epithelial linings. That suggests the existence of regulation of CK18 and CK18 mRNA expression.

Epithelial Cells ; Humans ; In Situ Hybridization ; Keratin-18 ; Keratins ; Odontogenic Cysts ; RNA, Messenger

OBJECTIVETo investigate the changes in phosphorylated JAK2 and STAT3 protein expression of and cell apoptosis following focal cerebral ischemia-reperfusion injury in rats.

METHODSA rat models of focal cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusion using modified filament method. Immunohistochemistry and Western blot analysis were used to detect the expression of P-JAK2 and P-STAT3 proteins, and TUNEL assay was employed to examine the cell apoptosis.

RESULTSP-JAK2 and P-STAT3 protein expression increased significantly after cerebral ischemia-reperfusion injury in rats. The immunoreactivity was prominent in the peripheral of the ischemic region and reached the peak level at 24 h of reperfusion, followed by slight decrement. The apoptotic cells increased obviously after cerebral ischemia-reperfusion injury, also reaching the peak level at 24 h of reperfusion.

CONCLUSIONThe expression of phosphorylated JAK2 and STAT3 may be involved in the ischemic cellular events including apoptosis. JAK2/STAT3 signaling pathway plays a role in the pathophysiological process of cerebral ischemia/reperfusion cell injury and repair.

Animals ; Apoptosis ; Blotting, Western ; Immunohistochemistry ; In Situ Nick-End Labeling ; Infarction, Middle Cerebral Artery ; physiopathology ; Janus Kinase 2 ; metabolism ; Male ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; genetics ; physiopathology ; STAT3 Transcription Factor ; metabolism

OBJECTIVE: To compare the results between auditory steady-state response (ASSR) and 40 Hz auditory event related potential (AERP), and explore the accuracy of hearing thresholds by using ASSR and AERP and the clinic forensic value. METHODS: Thirty seven ears were tested with pure-tone audiometer, 40Hz AERP and ASSR, respectively. All the volunteers in our study were awake during 40 Hz AERP test and ASSR test. RESULTS: Thresholds acquired with ASSR and 40Hz AERP test had a close correlativity and showed higher than those acquired with PTA test. There was no significant difference between the accuracy of ASSR and 40Hz AERP in estimating pure-tone thresholds. CONCLUSION After determining the correct value, ASSR can be used directly to evaluate hearing loss objectively.
Acoustic Stimulation ; Adult ; Audiometry, Evoked Response ; Audiometry, Pure-Tone/methods* ; Auditory Threshold ; Evaluation Studies as Topic ; Evoked Potentials, Auditory, Brain Stem/physiology* ; Female ; Hearing Loss, Sensorineural/physiopathology* ; Humans ; Male ; Middle Aged ; Predictive Value of Tests ; Sleep/physiology* ; Wakefulness ; Young Adult

OBJECTIVE: To study the mechanisms of cultured neurons injury mediated by nitric oxide and free oxygen radical during hypoxia and oxidative stress. METHODS: The cultured newborn rat neurons were treated with hypoxia, H2O2 and pretreated superoxide dismutase (SOD) respectively. We examined the content of NO, malonaldehyde (MDA), lactate dehydrogenase (LDH) and SOD in cultured supernatant. RESULTS: Comparing with that of control group, the content of NO, LDH, MDA increased and the content of SOD decreased in hypoxia group and H2O2 group. The content between NO and SOD showed the negative correlation. Administration of 200 U/ml SOD before oxidative stress could efficiently decrease the release of NO, LDH and MDA in neurons. The content of NO, LDH and MDA manifested in positive correlation in each group. CONCLUSION Hypoxia and oxidative stress increased NO production which strengthen neurons injury induced by free radical. SOD played an important role in elimination of free oxygen radicals and protecting neurons from injury by NO.
Animals ; Animals, Newborn ; Cell Hypoxia ; Cells, Cultured ; Hydrogen Peroxide/toxicity* ; Neurons/pathology* ; Nitric Oxide/physiology* ; Oxidative Stress ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase/pharmacology*

Objective To test the possibility of reciprocal pathways between medullary visceral zone (MVZ) and hypothalamic paraventricular nucleus (PVN) or supraoptic nucleus (SON) following hyperosmotic stimulation. Methods Hyperosmotic pressure animal model was established by administering3% sodium chloride as drinking water to rats. The distributions and expressions ofHRP retrogradely labeled neurons, Fos, tyrosine hydroxylase (TH) or vasopressin (VP) positive neuron and lial fibrillary acidic protein (GFAP) positive astrocytes (AST) in MVZ, SON and PVN were observed by quadruple labeling methods of WGA-HRP retrograde tracing combined with anti-Fos, TH (or VP) and GFAP immunohistochemical technique. Results Fos positive neurons within the MVZ, PVN and SON increased markedly. There were also a large number of GFAP positive structures in the brain and their distribution pattern was fundamentally similar or analogous to Fos positive neurons in the above-mentioned areas. The augmented GFAP reactivities took on hypertrophic cell bodies, thicker and longer processes.Quadruplicate immunohistochemical staining showed that a neuron could be closely surrounded by many AST and they formed neuron-astrocytic complex (N-ASC). Conclusion The neurons and AST might be very active following hyperosmotic pressure and N-ASC as a functional unit might serve to modulate the osmotic pressure. There was reciprocal osmoregulation pathways between the MVZ and SON or PVN in the brain.

Objective To explore the effect of edaravone (ED) on the neurological functionaldeficits, apoptosis and expression of caspase-3 protein following focal cerebral ischemia/reperfusion(I/R)injury in rats. Methods A total of 24 male Sprague-Dawley (SD) rats were randomly allocated intothe sham-operation group, cerebral I/R group, normal saline treatment group and ED treatment group, 6rats in each group. Rat models with focal cerebral I/R injury induced by middle cerebral artery occlusion(MCAO) were established using a modified suture method. ED (3mg/kg) or equal volume of normalsaline was injected intraperitoneally immediately after cerebral ischemia and 12 h after reperfusion in thetreatment groups;the rats in sham-operation group underwent the same modeling procedure withoutischemia by nylon suture. The neurological behavioral deficits were evaluated 24 h after I/R injury;,immunohistochemical staining and Western blot assay were applied to detect the change in the expressionof caspase-3 protein; in situ TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay was used tostudy the change in neuronal apoptosis. Results The scores of neurological behavioral deficit scale,the positive cells and expression of caspase-3 protein, and the apoptotic cells in the ED treatment groupwere significantly decreased, compared with that of the I/R group and normal saline treatment group(P<0.05 for each comparison). Conclusion ED may effectively reduce neuronal apuptosis andneurological functional deficits after cerebral I/R injury, which might be related with the inhibition of thecaspase-3 protein expression.