Speech evoked brainstem responses (s-ABRs) elicited by a speech syllable /da/ are composed of four parts: onset response (OR), transitional response, frequency following response (FFR) and offset response. FFR elicited by periodic events behaves like a quasi-periodic waveform corresponding to the stimulus sounds. The fast Fourier transform based spectra are commonly used to exam the characteristics of s-ABR in practice, which is, however, unable to trace the occurrence of the main components of s-ABR. The FFR is usually not obvious in the original individual s-ABR waveform. In this paper, we proposed a novel approach to observe the FFR by an instantaneous energy spectrum performed on the intrinsic mode functions (IMFs) after empirical mode decomposition (EMD) of the s-ABR. We demonstrated that the FFR is most pronounced on the second layer of IMFs. This finding suggests a new way which may be available to characterize and to detect the FFR better. This will benefit the clinic applications of s-ABRs.
Adult ; Brain Stem ; physiology ; Evoked Potentials, Auditory, Brain Stem ; physiology ; Female ; Fourier Analysis ; Humans ; Male ; Speech ; Speech Perception ; physiology ; Young Adult

OBJECTIVETo study the mechanism of hepatitis B virus infected patients who is negative for HbsAg.

METHODSDNA sequences of 46 patients were analyzed. In these patients, HBsAg was negative but HBV DNA was positive and six new HBsAg variants were identified. Four of the six variants were combined point mutants and two were insertion variants. These S genes were subcloned into eukaryotic expression vector EBO-plpp, and the recombinant eukaryotic expression plasmids were transfected into COS7 cells. Cell lines expressing mutant type HBsAg were obtained. The supernatants were detected by ELISA and RIA.

RESULTSOnly the two-amino acid-insertion variants could be detected and the others failed to react with polyclonal and monoclonal antibodies against HbsAg.

CONCLUSIONThe results indicated that the point mutations and insertions may result in a conformational change of the S gene, which affect HBsAg antigenicity, suggesting a possible relationship between the variants and the negative conversion of HBsAg of the patients.

Animals ; Antigenic Variation ; COS Cells ; Cercopithecus aethiops ; Hepatitis B Surface Antigens ; genetics ; immunology ; Hepatitis B virus ; genetics ; immunology ; Hepatitis B, Chronic ; immunology ; virology ; Humans ; Plasmids ; genetics ; Point Mutation ; Transfection

OBJECTIVETo study the effect and the possible mechanism of IL-6 on NMDA-excited neuronal discharges of rats in vitro.

METHODSThe cerebellar slices were prepared and spontaneous discharges of single cerebellar interposed nuclear (IN) neurons were recorded by extracellular recordings. The cerebellar slices were perfused with artificial cerebral spinal fluid (ACSF) containing N-methyl-D-aspartate (NMDA), IL-6, JAK inhibitor AG490. The changes in firing activities of the neurons treated with the drugs were recorded. The levels of phosphorylation at serine 897 site of NMDA receptor subunit 1 (NR1) in the neurons treated with various drugs mentioned above were detected by Western blot.

RESULTSThe discharge rates of the neurons that were treated with IL-6 together with NMDA were significantly lower than those of the neurons treated with NMDA alone. AG490 partially blocked the inhibitory effect of IL-6 on the NMDA-stimulated neuronal firing activity. The treatment of the neurons with IL6 and NMDA led to a concentration-dependent suppression of the phospho-NR1 expression relative to those neurons treated with NMDA alone. AG490 blocked the effect of the IL-6-induced depression of phospho-NR1 expression.

CONCLUSIONIL-6 inhibits NMDA-stimulated neuronal firing activity, and simultaneously down-regulates the phosphorylation of NR1 at serine 897 site.

Animals ; Cerebellum ; drug effects ; metabolism ; In Vitro Techniques ; Interleukin-6 ; pharmacology ; N-Methylaspartate ; pharmacology ; Nerve Growth Factors ; metabolism ; Neurons ; drug effects ; metabolism ; physiology ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; metabolism

OBJECTIVETo study the distribution of human immunodeficiency virus-1 (HIV-1) genotypes in Hubei province.

METHODSEpidemiological survey was carried out to HIV-1 carriers who were identified in Hubei province. HIV-1 env V3-V4, gag P17/24 and the first exon of tat region were amplified by nested-polymerase chain reaction(nPCR) .The sequences were determined, and phylogenetic analyses were then performed.

RESULTS4 HIV-1 strains or circulating recombinant forms (CRFs) were identified in Hubei province with subtype B' the predominant which covered 5 kinds of populations including former blood donors, blood receivers, spouses of the infected people, sex workers and their clients, homosexuals, mainly distributed in the areas with many former blood donors. CRF08-BC and CRF01-AE were found distributed in economically more developed cities or southern area of the province, and the major transmission routes was through sexual contact. Only 1 patient, an injecting drug user, was identified having subtype C.

CONCLUSIONSubtype B' was the main epidemic subtypes in Hubei province while CRF08-BC, CRF01-AE and subtype C were also circulating in the province, indicating the transmission of the disease might to become more complex.

China ; epidemiology ; HIV Infections ; epidemiology ; HIV-1 ; classification ; Humans ; Molecular Epidemiology ; Phylogeny ; RNA, Viral ; genetics ; Sequence Analysis, RNA

OBJECTIVETo investigate the characteristic of subtypes and genetic diversity of HIV-1 circulating in Hubei province and its molecular epidemiological linkages with regard to risk factors of viral transmission.

METHODSplasma samples of 80 diagnosed individuals was characterized. The gene fragments of gag were amplified by reverse transcriptase polymerase chain reaction (RT-PCR) and HIV-1 genotypes were determined based on the nucleotide sequences of gag region.

RESULTSSeven HIV-1 group M subtypes or CRF including B, B', G, CRF01-AE, CRF07-BC, CRF08-BC and CRF15-01B were identified. CRF01-AE was found to be the most dominant subtype (48.4%) followed by CRF7-BC (22.6%) and B' (12.9%).

CONCLUSIONThe data from this study indicate the existence of multiple HIV-1 subtypes or CRFs in Hubei province and the surveillance of HIV-1 gene variation should be paid more attention to.

Adolescent ; Adult ; Aged ; Child ; China ; epidemiology ; Genotype ; HIV Infections ; epidemiology ; virology ; HIV-1 ; classification ; genetics ; isolation & purification ; Humans ; Male ; Middle Aged ; Phylogeny ; Young Adult ; gag Gene Products, Human Immunodeficiency Virus ; genetics

OBJECTIVETo study the potentiality of osteanagenesis of the hematomas formed around the fractures and that of the marrow stroma cells, evaluate the effect of the combined trans-plantation of the hematoma and the marrow stroma cells, to explore a new method to accelerate the union of fracture.

METHODSThe bone defect models were made on the tibias of the New-Zealand's rabbits. The hematomas formed around the fracture were taken out 3 days latter after the operation, the marrow stroma cells were abstracted from the femoral marrow simultaneously. And then the mixture of the hematoma and the marrow stroma cells were transplanted to the defects of the tibias in the experiment group, and the hematoma transplanted simply to the same place in the control group. The radio-graph and the histological observation of the osteotylus were carried out regularly post-operation.

RESULTS1) There was a significant difference in osteotylus quantity between the two groups: more osteotylus and obvious periosteal proliferation were found in the experiment group than that in the control group which accepted the transplantation of the hematomas alone. 2) There was a significant difference in osteoblast number between the two groups: more sclerotomal-like cells were observed under the microscope in the experiment group than that in the control group.

CONCLUSIONMarrow stroma cells have great potentiality of osteoanagenesis. The result of combined transplantation of the marrow stroma cells and the hematomas is more effective than that of simple transplantation of the bone hematoma.

Animals ; Blood Cells ; transplantation ; Bone Marrow Transplantation ; Female ; Fracture Healing ; Hematoma ; surgery ; Humans ; Male ; Mesenchymal Stem Cell Transplantation ; Rabbits ; Random Allocation ; Stromal Cells ; transplantation ; Tibia ; injuries ; physiopathology ; surgery ; Tibial Fractures ; physiopathology ; surgery ; therapy ; Transplantation, Autologous

OBJECTIVETo observe the effects of inhibiting stromal cell derived factor-1 (SDF-1) expression by RNA interference (RNAi) on adhesion and drug sensitivity of Jurkat cells co-cultured with bone marrow stromal cells.

METHODSSDF-1 specific short hairpin RNA (shRNA) expressing plasmid was transferred into cultured human acute leukemic bone marrow stromal cells, positive clones were isolated by screening G418 resistance (Group A) , SDF-1 protein level in culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA). The adhesion rates to bone marrow stromal cells layer and the drug sensitivity to doxorubicin of co-cultured Jurkat cells were detected by cell counting and MTT assay, respectively. The un-transfected bone marrow stromal cells of acute leukemia patient (Group B) or normal subject (Group C) were taken as control.

RESULTSThe level of secreted SDF-1 protein (pg/10(5) cells/week) in the supernatants of Group A, B and C were 1920 +/- 205, 12,370 +/- 1355 and 6620 +/- 770, respectively. Of co-cultured Jurkat cells in Group A, B and C, the adhesion rates after 24 h co-culturing were (28.8 +/- 2.6)%, (57.4 +/- 3.8)% and (45.2 +/- 4.0)%, respectively, and the IC50 values of doxorubicin were 585, 6162 and 1758 nmol/L, respectively.

CONCLUSIONDown-regulating SDF-1 expression of bone marrow stromal cells by RNAi reduces adhesion rates and enhances drug sensitivity to doxorubicin of their co-cultured Jurkat cells.

Bone Marrow Cells ; metabolism ; Cell Adhesion ; Cells, Cultured ; Chemokine CXCL12 ; genetics ; metabolism ; Coculture Techniques ; Drug Resistance, Neoplasm ; Gene Expression ; Humans ; Jurkat Cells ; RNA Interference ; Stromal Cells ; metabolism

OBJECTIVETo study the effects of RNA interference inhibiting stromal cell derived factor-1 (SDF-1) expression on the proliferation and apoptosis of co-cultured Jurkat cells.

METHODInhibition of SDF-1 expression by RNA interference (RNAi) was achieved by transferring SDF-1 specific short hairpin RNA (shRNA) expressing plasmid into cultured human acute leukemic bone marrow stromal cells. Resistant clones were obtained by G418 selection (group A). The concentration of SDF-1 protein in culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA). The population double time (PDT), cell cycles, apoptosis rates and the expressions of PCNA, Bcl-2/Bax, Fas/FasL of co-cultured Jurkat cells were detected by cells counting, flow cytometry. TdT-mediated dUTP nick-end labelling (TUNEL) and immunocytochemistry (ICC), respectively. The un-transfected acute leukemic (group B) and normal (group C) bone marrow stromal cells were taken as controls.

RESULTSThe content of SDF-1 protein in supernatant of group A\[(384 +/- 41) pg/ml] was significantly lower than that in group B[(2474 +/- 271) pg/ml] or group C[(1324 +/- 154) pg/ml]. As group A compared with group B and group C, the PDT of co-cultured Jurkat cells was prolonged (group A: 42 h, vs group B: 29 h, group C: 33 h), and G(0)/G(1) stage cells increased [group A: (28.47 +/- 2.39)%, vs group B: (19.43 +/- 2.80)%, group C: (27.15 +/- 2.07)%], S stage cells decreased [group A: (25.57 +/- 1.90)%, vs group B: (74.48 +/- 3.23)%, group C: (60.99 +/- 2.33)%], G(2)/M stage cells increased [group A: (45.96 +/- 3.24)%, vs group B: (6.09 +/- 1.96)%, group C: (11.86 +/- 1.98)%], the apoptosis rate increased [group A: (15.2 +/- 0.8)%, vs group B: (5.4 +/- 0.7)%, group C: (9.5 +/- 0.4)%], and the expressions of PCNA, Bcl-2, Fas decreased; whereas the expressions of Bax and FasL were increased.

CONCLUSIONThe inhibition of SDF-1 expression in bone marrow stromal cells inhibits the proliferation and promotes the apoptosis of co-cultured Jurkat cells.

Apoptosis ; genetics ; Bone Marrow Cells ; metabolism ; Cell Proliferation ; Cells, Cultured ; Chemokine CXCL12 ; genetics ; Coculture Techniques ; Gene Expression ; Humans ; Jurkat Cells ; RNA Interference ; Stromal Cells ; metabolism ; Transfection

AIM: To investigate whether neural stem cell-derived exosomes promote the viability and inhibit the apoptosis of neurons under cobalt chloride(CoCl2)-induced hypoxia in vitro.METHODS:The exosomes were isolated based on ultracentrifugation.The exosomal markers,ALG-2-interacting protein X(Alix)and tumor susceptibility gene 101 (TSG101)were identified by Western blot.The shape of exosomes was observed under transmission electron microscope (TEM).The size distributions of exosomes were analyzed by nanoparticle analysis(qNano).The neurons were exposed in CoCl2at different doses(200~600 μmol/L)for 24 h.The exosomes were co-cultured with the neurons pre-treated with CoCl2.The viability and apoptosis of the neurons were measured by CCK-8 assay and TUNEL method.RESULTS: The exosomes released from the neural stem cells expressed exosomal markers Alix and TSG 101.They also displayed a cup-shaped appearance observed under TEM and their sizes were(95.0 ±23.5)nm(n=370).The neuronal viability was sig-nificantly inhibited by CoCl 2in a dose-dependent manner(P<0.05).After treatment with exosomes,the viability of the neuron pre-treated with CoCl2was increased and the apoptotic rate was decreased(P<0.05).CONCLUSION: Neural stem cell-derived exosomes promote the viability and inhibit the apoptosis of rat neurons uneder hypoxia.

The maximum length sequence (m-sequence) has been successfully used to study the linear/nonlinear components of auditory evoked potential (AEP) with rapid stimulation. However, more study is needed to evaluate the effect of the m-sequence order in terms of the noise attenuation performance. This study aimed to address this issue using response-free electroencephalogram (EEG) and EEGs with nonlinear AEPs. We examined the noise attenuation ratios to evaluate the noise variation for the calculations of superimposed averaging and cross-correlation, respectively, which constitutes the main process in the deconvolution method using the dataset of spontaneous EEGs to simulate the cases of different orders (order 5 to 12) of m-sequences. And an experiment using m-sequences of order 7 and 9 was performed in true cases with substantial linear and nonlinear AEPs. The results demonstrate that the noise attenuation ratio is well agreed with the theoretical value derived from the properties of m-sequences on the random noise condition. The comparison of waveforms for AEP components from two m-sequences showed high similarity suggesting the insensitivity of AEP to the m-sequence order. This study provides a more comprehensive solution to the selection of m-sequences which will facilitate the feasible application on the nonlinear AEP with m-sequence method.