BACKGROUND:The electrical impedance tomography (EIT) is a kind of examination that is used to non-invasively measure the change and distribution of electrical bio-impedance by reconstructing the frequency response obtained by electrical stimuli applied onto the human body. The characteristics of impedance of any tissues are of great importance to the imaging of EIT and locating and monitoring the lesion focus.OBJECTIVE: To measure the human brain impedance in the frequency range from 0.1 Hz to 1 MHz and to compare these with those of other human tissues and the rabbit brain tissues.DESIGN: An observational experiment.SETTING:The Department of Medical Electric Engineering of the Biomedical Engineering College of the Fourth Military Medical University of Chinese PLA.MATERIALS:The experiment was conducted at the Otolaryngology Laboratory, Department of Medical Electric Engineering of Biomedical Engineering College, Fourth Military Medical University of Chinese PLA from April, 2000 to June, 2000. Two brains were harvested from two cadavers of adult men who died in less than 12 hours before the brains were taken.INTERVENTIONS :The brains were divided into 15 samples and the Solartron 1255B frequency resoonse analyzer was used to measure the complex impedance of human brain in vitro with four-electrode measurement method in the frequency range from 0.1 Hz to 1 MHz.There were also impedance interface (1294)and self-made experimental measurement box.MAIN OUTCOME MEASURES:The resistivity frequency response,curves of real part and imaginary part of complex impedance as well as the equivalent circuit model of the complex impedance.RESULTS:The resistivity of human brain tissues was about 1 200 Ω·cm in the frequency range of 0.1-100 Hz.But it decreased to 650 Ω·cm in the frequency range of 100-1×106 Hz. The real part of complex impedance remained steady in the frequency range of 0.1-100 Hz and it decreased along with the increase of frequency in the range of 100-1×106 Hz. The absolute value of frequency response curves of the imaginary part of human brain's complex impedance presented a tendency of monotonic increase.CONCLUSION: The resistivity and the real part of complex impedance curve of human brain were in accordance with those of other tissues such as muscles, the liver, kidney and lungs. The frequency response curve of the imaginary part of human brain's complex impedance was different from that of other animal tissues (such as muscles, the liver and kidney) but was in accordance with that of rabbit brain tissues in vitro. The construction of the equivalent circuit model obtained was more complex than other models known.

A 48-year-old female presented with a one-week history of painful and enlarged lymph nodes in the left neck.One-week systemic treatment with antibiotics resulted in no obvious improvement.Skin examination revealed palpable lymph nodes between the left lateral cervical papillae and clavicle,which appeared as a string of beads with a little mobility and obvious tenderness.The largest diameter of enlarged lymph nodes was about 2 cm.No enlarged lymph nodes were palpable in the other body sites.Histopathologically,histiocytes of various shapes,immunoblasts and plasmacytoid monocytes markedly proliferated with different degrees of karyorrhexis.Immunohistochemistry revealed that the lesions were positive for CD3,CDS,CD68,mouse macrophage inflammatory protein,and CD20.A diagnosis of histiocytic necrotizing lymphadenitis was made.

The association of spontaneous intracranial hypotension with cerebral venous sinus thrombosis is rare. We report here a case of extensive cerebral venous sinus thrombosis involving three sinuses following spontaneous intracranial hypotension. The patient presented no other thrombotic risk factors except for spontaneous intracranial hypotension. This case adds to the evidence that spontaneous intracranial hypotension is a risk factor for cerebral venous sinus thrombosis.

The paper introduced the recent development of optical tweezers array.The particle manipulation system could be set up based on several methods,such as acousto-optics deflectors(AOD),diffractive optical elements(DOE),spatial light modulators(SLM),interference technique,vertical cavity surface emitting laser(VCSEL),optical fibers and micro-lens arrays as well.The principle,specification and basic structure of each method were introduced and analyzed briefly.Taking the advantage of particle trapping,optical tweezers array was very useful for manipulation of micron size particles,such as cells.Combining with microfluidics and MEMs fabrication,optical tweezer array,the ultraminiature and portable particle sorting system,would be a good choice for space biological research.

Objective To determine the origin of cord serum leptin and its relationship with neonatal anthropometry. Methods Sixty five women and their babies took part in this prospective cohort study. Blood was taken from the women just before delivery and from the umbilical cord of their babies at delivery. Serum leptin was measured by radio immunoassay. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between serum leptin concentrations and anthropometric measures and multiple regression analysis then applied to determine which variables remained independently associated with leptin. Results The leptin concentration ( ?s )in maternal serum was (19.93?7.21) ng/mL and in cord blood was (10.50?3.45) ng/mL. Cord leptin levels correlated with placental weight, neonatal birthweight, skinfold thickness and ponderal index but not with maternal leptin levels. The correlation with Placental weight and neonatal birthweight remained significant after multiple regression analysis. Conclusions Relatively big serum leptin concentration gradient between mother and umbilical vessels indicates that placenta might play an important role in leptin production. We hypothesize that leptin might play an important role during pregnancy and fetal development.

Objective Study the effect of NMDA receptor antagonist GAPA on the [Ca 2+ ]i of the bilirubin precipitated brain tissue. Methods 10 ug/g of GAPA was administrated peritoneally to Gunn rat with bilirubin induced encephalopathy, brain tissue suspensions was prepared, Fura 2/AM was loaded. the neural cytosolic Ca 2+ was measured by flurescence imaging analysis. Results The concentration of neural cytosolic Ca 2+ in bilirubin precipitated brain tissue was significantly more than that in the control group; NMDA receptor antagonist GAPA could significantly decrease the cytosolic Ca 2+ overload. Conclusion Cytosolic Ca 2+ overload was found in the bilirubin precipitated brain tissue. NMDA receptor antagonist GAPA could prevent the cytosolic Ca 2+ overload in bilirubin induced brain tissue.

Objective To study the role of placental leptin in intrauterine cord leptin production and its relationship with neonatal anthropometry. Methods Forty women and their babies were enrolled in this study. Placental tissue was obtained from mothers and assayed for leptin mRNA by reverse transcription/polymerase chain reaction (RT/PCR). Blood was taken from the umbilical cord of the babies at delivery. Serum leptin was measured by radio-immunoassay. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between placental leptin mRNA, serum leptin concentrations and anthropometric measures. Results Placental tissue expressed leptin mRNA at comparable or greater levels than adipose tissue. The placenta of the small for gestational age (SGA) neonates expressed leptin mRNA at significantly lower levels than that of the appropriate for gestational age (AGA) neonates (P=0.042), while the placenta of the large for gestational age (LGA) neonates expressed leptin mRNA at significantly higher levels than that of the AGA neonates (P=0.03). Placental leptin mRNA expression levels correlated with leptin concentrations in cord blood (r=0.61), newborn birth weight (r=0.60) and Ponderal Index (r=0.56). Conclusions Placenta provides a source of leptin for the growing fetus, and this placental leptin might be a growth factor in intrauterine fetal development.

Sequences analysis revealed Grass carp reovirus (GCRV) s10 was 909 nucleotides coding a 34 kDa protein denoted as VP7, which was determined to be a viral outer capsid protein (OCP). To obtain expressed OCP in vitro, a full length VP7 gene was produced by RT-PCR amplification, and the amplified fragment was cloned into T7 promoted prokaryotic expression vector pRSET. The recombinant plasmid,which was named as pR/GCRV-VP7,was then transformed into E.coli BL21 host cells. The data indicated that the expressed recombinant was in frame with the N-terminal fusion peptide. The over-expressed fusion protein was produced by inducing with IPTG, and its molecular weight was about 37kDa, which was consistent with its predicted size. In addition, the fusion protein was produced in the form of the inclusion body with their yield remaining steady at more than 60% of total bacterial protein. Moreover,the expressed protein was able to bind immunologically to anti-his-tag monoclonal antibody (mouse) and anti-GCRV serum (rabbit). This work provides a research basis for further structure and function studies of GCRV during entry into cells.

BACKGROUND: Electrical impedance tomography (EIT) uses non-invasive signals to probe the human body and then detect the responses on the boundary of the body in order to reconstruct an impedance distribution inside the body. Compared to CT and MRI, EIT takes the advantages of realtime technique, lower cost and easiness for both continuous monitoring and functional imaging.OBJECTIVE: This study was designed to perform the in vivo measurement of the rabbit brain impedance frequency response before and after ischemia. And it was to verify the feasibility of EIT in brain functional imaging by ischemia brain functional imaging using EIT.DESIGN: It was a single-sample experiment.SETTING: It was conducted at the Department of Medical Electronic Engineering, Faculty of Biomedical Engineering, Fourth Military Medical University of Chinese PLA.MATERIALS: This study was conducted at the Department of Medical Electronic Engineering, Faculty of Biomedical Engineering, Fourth Military Medical University of Chinese PLA from August to September 2001 and 10 healthy rabbits were selected.METHODS: Cerebral ischemia animal model was made using carotid artery ligation. Then the in vivo measurement of the rabbit brain impedance frequency response before and after ischemia was performed.Dynamic unilateral brain blood supply was recorded using EIT imaging.curves were plot before and after ischemia in the frequency range from 0.1 Hz EIT imagingRESULTS: Nine rabbits entered the statistical analysis and one was omitimpedance increased significantly. The ratio of increasing impedance can be up to 75% at frequencies lower than 10 Hz. And in the range from 1 kHz namic imaging showed that the changes in unilateral brain blood supply is accordant with the corresponding regions having a changing impedance.CONCLUSION: The changes in brain tissue impedance before and after ischemia can be imaged and it could be used as a variable for EIT imaging.

A 73-year-old man developed a skin-colored granule-sized papule on the scrotum 10 years prior to the presentation,which had increased in size and number without obvious symptoms.Histopathological examination showed multiple enlarged intradermal cysts.The cyst wall consisted of one or two layers of flat or columnar cells.Decapitation secretion was seen in the inner layer cells,and the out layer of cysts was formed by flat or cubic myoepithelial cells.A diagnosis of apocrine hidrocystoma of the scrotum is made.