Biomedical subjects
Publications and source records attributed to Bo Liu.
The first experimental observation of long-lived triply charged fluorofullerene anions in the gas phase obtained from C60F48 is reported. The existence of a Coloumb barrier trapping the third electron in the trianion is supposed to be responsible for detection of the species which is estimated to have negative third electron affinity.
OBJECTIVE: To summarize the experience of cervical artificial disc replacement. METHODS: The clinical data of 29 cases undergoing standard Bryan artificial disc replacement, 15 males, aged 47 (32 approximately 60), and 14 females, aged 49 (40 approximately 65), 16 with cervical spondylotic myelopathy and 13 with cervical disc herniation, were analyzed. Twenty patients underwent replacement of one disc and 4 patients underwent replacement of 2 discs. A follow-up of 3.7 months was conducted. RESULTS: No complication was seen intra-operatively and post-operatively. All patients felt improvement of preoperative symptoms immediately postoperatively and returned to work 2 approximately 4 weeks after the operation. The JOA scoring was improved by 56%. The average motion range of the operative intervertebral space was 12.2 degrees before operation and was 10.9 degrees after the operation in vertical direction. The average motion range of the operative intervertebral space in vertical direction was 12.2 degrees before operation and was 10.9 degrees after the operation. The average motion range of the adjacent intervertebral space in vertical direction was 10.9 degrees before operation and was 9.4 degrees after the operation. The satisfaction rate of the patients was 94%. CONCLUSION: The short-term effect of standard Bryan artificial disc replacement is satisfactory.
OBJECTIVE: To compare inflammatory peripheral arthritis in wild-type and high molecular weight kininogen (HK)-deficient rats, both on the genetically susceptible Lewis background. METHODS: By backcrossing Brown-Norway HK-deficient rats with Lewis rats for 6 generations, 2 new strains were produced, wild-type F6 and HK-deficient F6, each with a 98.5% Lewis genome. Inflammatory arthritis was induced by intraperitoneal injection of peptidoglycan-polysaccharide (PG-PS), and the clinical, histopathologic, and biochemical responses were compared in both strains. RESULTS: Eighteen days after PG-PS injection, rats with normal concentrations of HK showed weight loss and marked increase in hind ankle diameter with severe synovial inflammation and cartilage abnormalities. In contrast, HK-deficient rats showed no weight loss (P < 0.05), no increase in hind ankle diameter (P < 0.05), and an absence of inflammatory changes (P < 0.05), as measured by the histologic and morphometric Mankin grading system for synovial and cartilage injury. CONCLUSION: Plasma HK is a key mediator of acute and chronic inflammatory arthritis in genetically susceptible Lewis rats.
BACKGROUND & AIMS: Growth hormone (GH) is used to treat growth delay in children with Crohn's disease and in patients with short-bowel syndrome. GH can increase collagen accumulation in intestinal mesenchymal cells, raising concern that GH therapy could exacerbate fibrosis in patients with Crohn's disease. We tested if GH treatment altered inflammation or fibrosis during chronic, experimental granulomatous enterocolitis. METHODS: Ileum and cecum of Lewis rats were subserosally injected with peptidoglycan-polysaccharide (PG-APS) or control human serum albumin. At the onset of chronic PG-APS-induced inflammation, rats were administered recombinant human GH or vehicle for 14 days. Fibrosis and inflammation were quantified by gross gut disease scoring, histologic scoring, type I collagen, and cytokine expression in cecum. Abundance and localization of suppressor of cytokine signaling-3 (SOCS-3) messenger RNA and/or protein were determined in cecum. Effect of GH, cytokines, or PG-APS on SOCS-3 synthesis was measured in intestinal myofibroblasts. Myofibroblasts overexpressing SOCS-3 were used to test whether SOCS-3 inhibits collagen accumulation. RESULTS: In PG-APS-injected rats, GH modestly reduced gross adhesions and mesenteric contractions, cecal fibrosis score, and collagen expression, but had no effect on intestinal inflammation. GH increased SOCS-3 messenger RNA and protein abundance in PG-APS rats and SOCS-3 messenger RNA was localized to the periphery of granulomas. GH in combination with cytokines or PG-APS, but not alone, induced SOCS-3 synthesis in intestinal myofibroblasts. Myofibroblasts overexpressing SOCS-3 showed reduced cytokine-induced collagen accumulation. CONCLUSIONS: GH modestly reduces intestinal fibrosis associated with chronic experimental enterocolitis and stimulates expression of antifibrogenic SOCS-3, suggesting that GH therapy in inflammatory bowel disease should not exacerbate fibrosis.
CONCLUSIONS: The data collected in this study indicated that first Neural Response Imaging (NRI) thresholds had a better correlation with HiResolution most comfortable loudness (M) levels than tNRI thresholds. Electrically evoked auditory reflex thresholds (EARTs) had a higher correlation with HiResolution M levels than tNRI thresholds and a lower correlation than first NRI thresholds. NRI is a very useful method for programming the cochlear implants of young children who cannot demonstrate a reliable judgment of loudness. OBJECTIVE: To investigate how HiResolution sound processing, designed to deliver high-rate stimuli, relates to EARTs and electrically evoked compound action potential measurements produced by low-rate stimuli. MATERIAL AND METHODS: Nine profoundly hearing-impaired children and adults aged 6-29 years participated in the study. NRI responses were elicited using pulse trains consisting of biphasic pulses at a pulse width per phase of 32 micros delivered at a frequency of 30 Hz using SoundWave programming software. Stimuli were delivered to the odd electrodes (1, 3, 5, 7, 9, 11, 13 and 15) along the array. tNRI (NRI threshold) and first NRI thresholds were recorded for each stimulating electrode. "Speech bursts" stimuli used in EARTs recording were delivered to four electrodes at a time and stapedial reflexes were recorded from the impedance bridge. The M levels used were those used by each patient in their everyday HiResolution programs. RESULTS: For 8 patients (53 stimulating electrodes) the correlation between tNRI threshold and M level was r=0.675 (p=0.000) and that between first NRI thresholds and M level was r=0.741 (p=0.000). On average the M-level value was 20 CU (Current Unit) lower than the first NRI threshold value and 12 CU higher than the tNRI threshold value. The M-level patterns across the electrode array overall were similar to the tNRI or first NRI threshold patterns. For 7 patients (112 stimulating electrodes) the correlation between EART and M levels was r=0.710 (p=0.000). On average the EART value was 14 CU higher than the M-level value.
Axin1 and its homolog Axin2/conductin/Axil are negative regulators of the canonical Wnt pathway that suppress signal transduction by promoting degradation of beta-catenin. Mice with deletion of Axin1 exhibit defects in axis determination and brain patterning during early embryonic development. We show that Axin2 is expressed in the osteogenic fronts and periosteum of developing sutures during skull morphogenesis. Targeted disruption of Axin2 in mice induces malformations of skull structures, a phenotype resembling craniosynostosis in humans. In the mutants, premature fusion of cranial sutures occurs at early postnatal stages. To elucidate the mechanism of craniosynostosis, we studied intramembranous ossification in Axin2-null mice. The calvarial osteoblast development is significantly affected by the Axin2 mutation. The Axin2 mutant displays enhanced expansion of osteoprogenitors, accelerated ossification, stimulated expression of osteogenic markers and increases in mineralization. Inactivation of Axin2 promotes osteoblast proliferation and differentiation in vivo and in vitro. Furthermore, as the mammalian skull is formed from cranial skeletogenic mesenchyme, which is derived from mesoderm and neural crest, our data argue for a region-specific effect of Axin2 on neural crest dependent skeletogenesis. The craniofacial anomalies caused by the Axin2 mutation are mediated through activation of beta-catenin signaling, suggesting a novel role for the Wnt pathway in skull morphogenesis.
To explore the biological effects of shear stress on intact artery and the change of growth factor during stress-induced vascular remodeling, we established an artery organ-cultured system under stress in vitro, and the common carotid arteries of pigs were cultured under shear stress of 20, 5 and 0 dyn/cm2. PDGF-A synthesis of vascular smooth muscle cells (VSMCs) cultured for 1, 4 and 7 days were studied by immunohistochemical and computer image processing methods, and PDGF-B secretion of endothelial cells (ECs) cultured within 12 h were studied by ELISA. Results showed that PDGF-B increased obviously under shear stress of 5 dyn/cm2, and reached the highest point at about 3 h; PDGF-A synthesis also obviously increased under low shear stress in 7 days. Increasing of PDGF synthesis promotes phenotype switch and proliferation of VSMC. It may have important influence on artery remodeling under low shear stress.
OBJECTIVE: To study the clinicopathologic features of central giant cell granuloma (CGCG) of the jaws and the relationship between the pathologic features and its clinical behavior. METHODS: Histologic, radiographic and follow-up information for 31 cases of central giant cell granuloma were reviewed. The histopathologic patterns were analyzed between nonrecurrent and recurrent cases for which the following-up information was available. RESULTS: The majority of the giant cell granuloma of the jaws occurred in patients under 30 with a predilection of females and mostly were involved in the mandible. The radiographic features of CGCG non-specific. The multinucleated giant cell scattered unevenly, the numbers of the nuclei were few and mostly 10-19. The marked fibrosis, the multiple area of hemorrhage, abundant hemosiderin and newly formed bone were always present in the lesions. No significant difference exited between the recurrence and nonrecurrence groups in the pathologic features. The patients with aggressive behavior showed more consistent with the recurrence. CONCLUSIONS: CGCG was a non-neoplastic lesion of the jaws which was different from the giant cell tumor. It was difficult to distinguish between the CGCG and giant cell tumor (GCT), and to predict its clinical behavior only by the histopathological patterns. It was helpful to combine the clinical presentation of CGCG with its treatment.
Oleaginous microorganisms are small portion of organisms that have ability to accumulate lipids over 20% of their biomass. These species can transform renewable material into microbial oil with similar fatty acid composition to that of plant-based oil. Some organisms may also produce glycerides with high content of poly-unsaturated fatty acids. Therefore, microbial lipids are considered as potential oil resource. Summarized here are some features of oleaginous species and recent developments on their biosynthetic machinery and metabolic regulation mechanism.
To explore primarily the reconstruction of biological tissue engineered blood vessel in vitro, the decellularised scaffolds were obtained from swine common carotid arteries by enzyme digestion, and vascular smooth muscle cells (VSMCs) were isolated from canine thoracic aorta and subcultured and purified. The VSMCs were seeded into the inner surface of scaffolds and they were cocultured in vitro for 4 weeks. Histological staining and transmission electron microscopy were used to observe the growth of canine VSMCs on swine decellularized arterial scaffolds. The results showed the seeded VSMCs grew well on the decellularized scaffold throughout the duration of 4 weeks, which suggests that the method in this article is practicable for reconstructing complete biological tissue engineering blood vessel.
OBJECTIVE: To propose a guideline of respiratory support for emergency patients. METHODS: To summarize the experiences gained in giving stepwise respiratory support (SRS) in 2,548 patients for emergency care (including 1,823 trauma patients and 725 non-trauma patients) between 1992 to 2002. RESULTS: There were 1,876 male and 672 female patients with the ratio of male to female 2.79:1. The age of patients ranged between 4 to 86 years, and the mean age of traumatic patients was (32.3+/-19.8) years, and the dominant ages were between 20 to 39. The mean age of non-traumatic patients was (65.2+/-17.3) years, and the dominant ages were between 50 to 69. The traumatic and non-traumatic patients accounted for 60.2% and 32.0% of all patients, respectively. The respiratory management included resuscitation positioning in 816 (32.0%), open airway and suctioning in 314 patients (12.3%), oxygenation through nostril or nasal intubation in 2,311 patients (90.7%), oxygenation by mask in 124 patients (4.9%), endotracheal intubation in 254 patients (10.0%), thyrocricocentesis or cricothyrotomy in 25 patients (1.0%), tracheotomy in 195 patients (7.7%), percutaneous tracheotomy in 58 patients (2.3%). SRW management included two types, four steps and ten ways. The two types included traumatic and non-traumatic; the four steps and ten ways included first step of manual treatment (including (1) resuscitation positioning, (2) open airway and suction and (3) chest-back press), second step oxygenation (including (4) oxygenation through nostril or nasal intubation, (5) oxygenation by mask, (6) endotracheal intubation), third step invasive airway support (including (7) thyrocricocentesis or cricothyrotomy and (8) tracheotomy or percutaneous tracheostomy), fourth step mechanic ventilation (covering (9) manual ventilation and (10) mechanical ventilator). CONCLUSION: The series of SRS management plan and principles can improve the respiratory support in rescuing emergency patients efficiently.
OBJECTIVE: The purpose of this study is to analyze the auditory capability of infants before and after cochlear implantation by using IT-MAIS questionnaire. METHOD: Eighty-six prelingually deaf patients participated in this study. They received a cochlear implant at the age of 1 to 3 yr. The audiologists who were trained for the research used the IT-MAIS questionnaire. Audiologists asked for the parents' answers face to face and recorded all the information about the patient's spontaneous auditory behavioural responses including vocalization, behaviour, spontaneous alerting to sound and deriving meaning from sound. The evaluation was performed before operation and 1 month, 3 months, 6 months, 1 year after switch-on. RESULT: The scores of question 1 were significantly different between pre-operation and 1, 3, 6, 12 months after switch-on (P = 0.000, 0.000, 0.000, 0.000). The scores of question 2 were significantly different between pre-operation and 6, 12 months after switch-on (P = 0.000, 0.000). The scores of question 3 were significantly different between pre-operation and 3, 6, 12 months after switch-on (P = 0.001, 0.000, 0.000). The scores of question 4 were significantly different between pre-operation and 3, 6, 12 months after switch-on (P = 0.002, 0.000, 0.000). The scores of question 5 were significantly different between pre-operation and 1, 3, 6, 12 months after switch-on (P = 0.046, 0.00, 0.000, 0.000, 0.000). The scores of question 6 were significantly different between pre-operation and 3, 6, 12 months after switch-on (P = 0.037, 0.000, 0.000). The scores of question 7 were significantly different between pre-operation and 3, 6, 12 months after switch-on ( P = 0.000, 0.000, 0.000). The scores of question 8 were significantly different between pre-operation and 6, 12 months after switch-on (P = 0.001, 0.001). The scores of question 9 were significantly different between pre-operation and 3, 6, 12 months after switch-on ( P = 0.023, 0.000, 0.000). The scores of question 10 were significantly different between pre-operation and 12 months after switch-on (P = 0.048). CONCLUSION: Most of the patients showed no consistent response to sound in everyday life before implantation. After cochlear implantation, a significant increase in auditory capability occurred. The children demonstrated faster development of vocalization behaviour and spontaneous alerting to sound than deriving meaning from sound.
OBJECTIVE: The purpose of this study is to compare the characteristics of psychophysical tests between cochlear implant children with large vestibular aqueduct syndrome and normal inner ear and to analyse the characteristics of psychophysical and impedance tests for cochlear implant patients with large vestibular aqueduct syndrome. METHOD: One hundred and thirty-one cochlear implant pre-lingual deafness patients participated in this study. They received cochlear implant surgery at the age of 1.5 to 12 years old from Nov, 1998 to Aug, 2003. The patients were divided into two groups. Group A had 111 patients with normal inner ear. Group B had 20 patients with radiographically proven large vestibular aqueduct syndrome. All of the patients were inserted with Nucleus 24M. The time of the first programming session was approximately 4 weeks after surgery. The psychophysical tests included T and C-Level tests. The programming techniques used in the test were suitable for the age of the patients. The R116 and R126 software were used to test the impedance of the electrodes automatically. RESULT: Using the independent-samples t-test, the impedance and T/C-Level of each electrode did not differ significantly between group A and B ( P > 0.05). The impedance and T/C-Level were not significantly different between group A and B at the time of switch-on, 1 week, 2 weeks, 3 weeks, 2 months, 3 months, 6 months, 9 months and 1 year after switch-on (P > 0.05). CONCLUSION: The parameters of mapping were not significantly different between cochlear implant children with large vestibular aqueduct syndrome and normal inner ear. The management and procedure of mapping used in cochlear implant children with normal inner ear can be used in the children with large vestibular aqueduct syndrome.
OBJECTIVE: To study the relaxants effects of six extractions from Chinese Herbs (neferine, tetrandrine, kakonein, scutellarin, ginsenoside Rgl and ginsenoside Rb1) on the corpus cavernosum tissue of rabbit in vitro. METHODS: Isolated stripes of rabbit corpus cavernosum tissue were precontracted with 10(-5) mol/L phenylephrine (PE). Relaxation in response to cumulative doses of six extracts at (10(-8) - 10(-3)) mol/L was determined. RESULTS: On rabbit cavernosal muscle stripes precontracted with PE, neferine, tetrandrine, kakonein and scutellarin showed dose dependent relaxation. IC50 values were 4.60 x 10(-6), 3.73 x 10(-5), 8.03 x 10(-4) and 3.33 x 10(-3) mol/L, respectively. However, in the meantime, it was found that the relaxant effects of ginsenoside Rgl and ginsenoside Rbl less significant to stripes precontracted with PE. When the final concentration was 10(-3) mol/L, the relaxations were only (16.32 +/- 5.45)% and (11.21 +/- 3.10)%. CONCLUSION: Among the six extracts which showed relaxant effects to rabbit cavernosal muscle stripes precontracted with PE, neferine had greater functions than the other five extracts.
OBJECTIVE: To study the audiological characteristics of newborns and infants who failed hearing screening. METHODS: One hundred and six infants failed hearing screening received follow-up study with routine audiological evaluations (auditory brainstem response, distortion product otoacoustic emission, tympanometry and visual reinforcement audiometry). RESULTS: Sixty-five infants (61.3%) of this group were normal hearing subjects and 39(36. 8% ) of the infants had hearing loss. Two cases (1.9%) received follow-up by phone. Fifteen cases (14.2%) with conductive hearing loss and 24 cases (22.6%) with sensorineural hearing loss. Thirteen (12.3%), 14 (13.2%), 6 (5.7%), and 6 (5.7%) cases were found to be mild, moderate, severe and profound hearing loss respectively. Diagnosis of hearing loss in the thirty-nine infants conducted a prevalence of 0.264% (39/14 785) of congenital hearing loss (both binaural and monaural). The hearing level of those cases with severe and profound hearing loss basically did not change, but that of cases with mild and moderate hearing loss changed. CONCLUSIONS: Early identification and intervention of infants with severe and profound hearing loss by 6 months of age were successful. Infants with mild and moderate hearing loss should be followed up to six or eight months and received routine audiologic evaluations.
OBJECTIVES: To study the quantitative relationship between the levels of serum liver fibrosis markers and fibrosis stages of liver tissues in patients with chronic hepatic diseases. METHODS: In 118 patients with chronic hepatitis, fatty liver or cirrhosis, their Serum levels of LN, HA, PCIII and CIV were investigated by EIA and their liver histological changes were studied. The relationship between the levels of serum LN, HA, PCIII and CIV and the degrees of liver tissue fibrosis was analyzed quantitatively by using the SPSS11.0. RESULTS: A correlation between the levels of serum LN, HA, PCIII and CIV and the histologically assessed grades of inflammatory activity was found (r = 0.394, 0.449, 0.443, 0.351, respectively, P <0.01). The correlation between the levels of serum LN, HA, PCIII and CIV and the histological assessed stages of liver fibrosis was strong (r = 0.456, 0.564, 0.476, 0.421 respectively, P <0.01). The levels of serum LN, HA, PCIII and CIV of the patients with a stage 2 liver fibrosis were 110 ng/ml, 110 ng/ml, 100 ng/ml and 70 ng/ml respectively, with sensibilities of diagnosing stage 2 liver fibrosis at 70%, 79%, 79% and 74% respectively. Their specificities in diagnosing stage 2 liver fibrosis were 68%, 72%, 64% and 73% respectively. The levels of LN, HA, PCIII and CIV in serum of these patients diagnosing cut-off value in stage 4 liver fibrosis (early cirrhosis) were 130 ng/ml, 140 ng/ml, 120 ng/ml and 70 ng/ml respectively. Their sensibility of diagnosing liver cirrhosis was 79%, 93%, 79% and 86% respectively. Their specificity of diagnosing liver cirrhosis was 66%, 82%, 72% and 61% respectively. As shown by the ROC curves in these patients, differentiating patients with cirrhosis or without cirrhosis, serum HA level was more valuable than LN, PCIII, CIV (the areas under the curves = 0.938 vs 0.775, 0.787, 0.791 ) When serum HA was higher than 190 ng/ml, the veracity of diagnosing liver cirrhosis was 93%. CONCLUSIONS: There is a certain quantitative relationship between the levels of LN, HA, PCIII and CIV in serum and the degrees of liver tissue fibrosis. The level of HA in serum is an important reference datum for early diagnosing liver cirrhosis.
Smooth muscle cells (SMCs) are exposed to both platelet-derived growth factor (PDGF) and type I collagen (CNI) at the time of arterial injury. In these studies we explore the individual and combined effects of these agonists on human saphenous vein SMC proliferation. PDGF-BB produced a 5.5-fold increase in SMC DNA synthesis whereas CNI stimulated DNA synthesis to a much lesser extent (1.6-fold increase). Alternatively, we observed an 8.3-fold increase in DNA synthesis when SMCs were co-incubated with CNI and PDGF-BB. Furthermore, stimulation of SMCs with PDGF-BB produced a significant increase in ERK-2 activity whereas CNI alone had no effect. Co-incubation of SMCs with PDGF-BB and CNI resulted in ERK-2 activity that was markedly greater than that produced by PDGF-BB alone. In a similar fashion, PDGF-BB induced phosphorylation of the PDGF receptor beta (PDGFRbeta) and CNI did not, whereas concurrent agonist stimulation produced a synergistic increase in receptor activity. Blocking antibodies to the alpha2 and beta1 subunits eliminated this synergistic interaction, implicating the alpha2beta1 integrin as the mediator of this effect. Immunoprecipitation of the alpha2beta1 integrin in unstimulated SMCs followed by immunoblotting for the PDGFRbeta as well as Src family members, pp60(src), Fyn, Lyn, and Yes demonstrated coassociation of alpha2beta1 and the PDGFRbeta as well as pp60(src). Incubation of cells with CNI and/or PDGF-BB did not change the degree of association. Finally, inhibition of Src activity with SU6656 eliminated the synergistic effect of CNI on PDGF-induced PDGFRbeta phosphorylation suggesting an important role for pp60(src) in the observed receptor crosstalk. Together, these data demonstrate that CNI synergistically enhances PDGF-induced SMC proliferation through Src-dependent crosstalk between the alpha2beta1 integrin and the PDGFRbeta.
Members of the kinesin superfamily are microtubule-based motor proteins that transport molecules/organelles along microtubules. We have identified similar internal motor kinesins, Kinesin-13A, from the cotton Gossypium hirsutum and Arabidopsis thaliana. Their motor domains share high degree of similarity with those of internal motor kinesins of animals and protists in the MCAK/Kinesin13 subfamily. However, no significant sequence similarities were detected in sequences outside the motor domain. In Arabidopsis plants carrying the T-DNA knockout kinesin-13a-1 and kinesin-13a-2 mutations at the Kinesin-13A locus, >70% leaf trichomes had four branches, whereas wild-type trichomes had three. Immunofluorescent results showed that AtKinesin-13A and GhKinesin-13A localized to entire Golgi stacks. In both wild-type and kinesin-13a mutant cells, the Golgi stacks were frequently associated with microtubules and with actin microfilaments. Aggregation/clustering of Golgi stacks was often observed in the kinesin-13a mutant trichomes and other epidermal cells. This suggested that the distribution of the Golgi apparatus in cell cortex might require microtubules and Kinesin-13A, and the organization of Golgi stacks could play a regulatory role in trichome morphogenesis. Our results also indicate that plant kinesins in the MCAK/Kinesin-13 subfamily have evolved to take on different tasks than their animal counterparts.