[The primary study on immunologic status of umbilical blood].
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Adolescent↗
Biomedical subjects
Jing Liu
Publications and source records attributed to Jing Liu.
[Eosinophils apoptosis in asthmatic children].
UNLABELLED: Prominent eosinophil airway inflammation is important in the pathogenesis of asthma. There is increasing evidence that the disorder of eosinophil apoptosis contributes to the mechanism. But most of the studies have been done in vitro or on animal models, very few were done among the adult asthmatics in vivo. OBJECTIVE: The aim of this study was to elucidate the relationship between the apoptotic eosinophils and Bcl-2 in asthmatic children in vivo. METHODS: Eleven mild to moderate asthmatic patients were recruited and the range of age was 7 - 14 years (9 males, 2 females), meanwhile 7 patients with lower respiratory infection were recruited as control and the range of age was 9 - 14 years (5 males, 2 females). Before and after inhaled glucocorticoid (GC) induced sputum, bronchoalveolar lavage (BAL), bronchial mucosa specimens and peripheral blood were obtained for measuring and comparing the changes of apoptotic EG(2)(+) cell by combining the techniques of TUNEL and immunohistochemistry, meanwhile the expression of Bcl-2 in bronchial mucosa specimens was measured by using the immunohistochemical assay. RESULTS: Before the inhalation of GC, the apoptotic EG(2)(+) cells in asthmatics were significantly lower than that in control group (P < 0.01), and the numbers of EG(2)(+) cell in asthmatics group were significantly higher than that in control group (P < 0.001). After the treatment apoptotic EG(2)(+) cells in asthmatics were increased (P < 0.01), and the numbers of EG(2)(+)cell were decreased (P < 0.01, P < 0.05 and P < 0.05, respectively), FEV(1)% was increased (P < 0.05). Before the inhalation of GC, the numbers of Bcl-2(+) cell in asthmatic airway submucosa were higher than that in control group (P < 0.05) but after the treatment the number of Bcl-2(+) cell did not change significantly. (4) Before and after GC treatment the percentages of apoptotic eosinophils of peripheral blood in vivo had no significant changes compared with those of control subjects (P > 0.05). There was a positive correlation between apoptosis of EG(2)(+) cell in sputum, BAL, airway submucosa and FEV(1)% (P < 0.05). CONCLUSION: Apoptosis of EG(2)(+) cell decreased in the airway of asthmatic children and inducing EOS apoptosis is one of the important mechanism of inhaled GC therapy for asthma.
Adolescent↗
[Morphology of olfactory bulb, olfactory tract blood supply affected by anthrosclersis and its clinical significance].
OBJECTIVE: In order to provide morphological evidences for olfactory defect cased by olfactory bulb, olfactory tract ischemia, the origins, numbers, distributions and pathological changes about olfactory bulb, olfactory tract arteries were studied. METHOD: The distributions and pathological changes of olfactory bulb, olfactory tract arteries in 80 sides of adult brain specimens were observed with operation microscope, among which the nourishing arteries and nerve of olfactory tract in two sides aged from 60 to 70 were observed pathohistologically. RESULT: The blood supply of olfactory bulb, olfactory tract comes mainly form artery cerebral and posterior communicainy. 10% of these 60 sides arteries were of multi-branch. 86.3% of them had atheroselerosis. 25.0% of the olfactory bulb and olfactory tract artery were blocked or narrow, and pathological changes in olfactory nerve such as atrophy were observed. CONCLUSION: Excluding other diseases, the olfactory defect in different degree of patients over 60 years old were caused possibly by atheroselerosis of the arteries at base of the brain.
Adult↗
[Dynamic monitoring on land cover in loess hilly and gully area by the methods of RS and GIS].
By the integration of RS and GIS, with the TM data obtained from Landsat 5 in 1990 and the ETMplus data from Landsat 7 in 2000, and after geometrical rectifying and amplifying and man-machine screen decoding data image, the map of eco-environment and land use/cover in Yanhe watershed and its vicinities in 1990 and 2000 was obtained respectively, and the results of statistic analyses showed that in comparing with 1990, the artificial land in 2000 increased by 31%, the area of agricultural land was stable and that of orchard was 2.82 times more, and the area of artificial forest increased remarkably and that of shrub was 6 times more. The coverage rate increased to 13.88%, and the area of wilderness was 44.8% of that in 1990. The quality of eco-environment was improved remarkably in this area.
Agriculture↗
Dosing sequence-dependent pharmacokinetic interaction of oxaliplatin with paclitaxel in the rat.
BACKGROUND: In a phase I clinical trial of oxaliplatin (OPT) in combination with paclitaxel (PXL), a pharmacokinetic interaction was observed when OPT was given as a 2-h i.v. infusion followed by a 1-h i.v. infusion of PXL. The purpose of this study was to use a rat model to evaluate whether the pharmacokinetic interaction between OPT and PXL is dosing sequence-dependent. METHODS: One group of rats was given OPT as a 2-h i.v. infusion followed by a 1-h i.v. infusion of PXL formulated in 50% Cremophor EL (CrEL)/50% ethanol (OPT-->fPXL), similar to the current phase I clinical protocol. In a second group of rats, the fPXL was infused first to reach a quasi-steady-state plasma level of PXL, followed by an i.v. bolus dose of OPT (CIfPXL-->OPT). In a third group of rats, fPXL was replaced with the formulation vehicle, CrEL, which was infused in the same manner as in the second group. Each combination was accompanied with a control of either OPT alone or with replacement of PXL with dextrose 5% in water (CID5W-->OPT). The total platinum (Pt) levels in plasma and plasma ultrafiltrate were measured by a validated inductively coupled plasma mass spectrometry (ICPMS) method. The protein binding, red blood cell (RBC) uptake and urinary elimination of Pt were also examined in each group of rats. RESULTS: The concentration-time profiles of plasma Pt and ultrafiltrable Pt followed triexponential decays in all groups of rats. In the rat receiving OPT-->fPXL, the terminal elimination rate constant (gamma) of plasma Pt increased, with essentially no change in the total body clearance (CL) and the AUC value, when compared to those without PXL infusion (CID5W-->OPT). The steady-state volume of distribution (V(ss)) of the ultrafiltrable Pt also showed an increase in the combination group receiving OPT-->fPXL ( P<0.01). These results were similar to those from the clinical trial, although the magnitude of change was less. However, in the CIfPXL-->OPT group, both CL and V(ss) of Pt in plasma and plasma ultrafiltrate decreased, with corresponding increases in AUCs ( P<0.01). The 24-h urinary elimination of total Pt increased in both combination groups, irrespective of the dosing sequence. No difference in protein binding of Pt was observed among the groups. There was a decrease in RBC uptake in the presence of steady-state level of fPXL, but the same was not observed in the OPT-->fPXL group. Additionally, similar results were observed with OPT in combination with CrEL alone. CONCLUSIONS: These results suggest that alterations in the pharmacokinetics of OPT by fPXL are dosing sequence-dependent and mainly caused by the formulation vehicle CrEL. It is suggested that the dosing sequence of fPXL followed by OPT would be more clinically favorable because it would prolong the residence of OPT in systemic circulation. It is further recommended that the use of other formulations of PXL without CrEL or docetaxel would avoid the complication effect of CrEL.
Animals↗
[Impact of high-normal blood pressure on risk of cardiocerebrovascular disease in 11 provinces in China].
OBJECTIVE: To explore the impact of high-normal blood pressure on the risk of cardiovascular disease in different sexes in China. METHODS: A cohort baseline study was carried out among 27 739 subjects (age 35 approximately 64 years) to survey the general demographic data, smoking status, blood pressure, blood lipids, height, weight, was circumference, and hip circumference. By the end of each year, a follow-up was made until 31 December 1999 to all 27 739 persons to record the events of cardiocerebrovascular diseases and deaths. No intervention was made to the cohort population during follow-up. Cox regression model was used to carry out multifactoral analysis of the relationship between normal high blood pressure and risk of cardiocerebrovascular diseases. RESULTS: (1) The high-normal blood pressure rate was 13.4% (14.8% for males and 11.8% for females) in this cohort. (2) Those with high normal blood pressure had more risk factors of cardiocerebrovascular diseases than those with ideal blood pressure. (3) During follow-up, the yearly standardized incidence rates of coronary heart diseases, cerebral apoplexy, and cardiocerebrovascular diseases were significantly higher among those with high normal blood pressure than among those with ideal blood pressure. (P < 0.000 1). (4) The relative risk of cardiocerebrovascular disease was 2.8765 among those with high normal blood pressure (95% CI 2.050 6 - 4.035 1 P < 0.000 1), 3.234 6 among males (95% CI 2.113 1 - 4.951 2, P < 0.000 1) and 2.335 0 among females (95% CI 1.318 3 - 4.135 9, P < 0.000 1). CONCLUSION: The relative risk of cardiovascular disease was significant higher among those with high normal blood pressure than those with ideal blood pressure in 11 provinces in China. The necessity of lowering high-normal blood pressure to reduce CVD need to be evaluated.
Adult↗
C2-amidoglycosylation. Scope and mechanism of nitrogen transfer.
A one-pot C2-amidoglycosylation reaction for the synthesis of 2-N-acyl-2-deoxy-beta-pyranosides from glycals is described. Glycal donors activated by the reagent combination of thianthrene-5-oxide (11) and Tf2O, followed by treatment with an amide nucleophile and a glycosyl acceptor, lead to the formation of various C2-amidoglycoconjugates. Both the C2-nitrogen transfer and the glycosidic bond formation proceed stereoselectively, allowing for the introduction of both natural and nonnatural amide functionalities at C2 with concomitant anomeric bond formation in a one-pot procedure. Tracking of the reaction by low-temperature NMR spectroscopy employing 15N- and 18O-isotope labels suggests a mechanism involving the formation of the C2-sulfonium glycosyl imidate 39 as well as oxazoline 37 as key intermediates in this novel oxidative glycosylation process.
Aza Compounds↗
Mutant DNA-binding domain of HSF4 is associated with autosomal dominant lamellar and Marner cataract.
Congenital cataracts cause 10-30% of all blindness in children, with one-third of cases estimated to have a genetic cause. Lamellar cataract is the most common type of infantile cataract. We carried out whole-genome linkage analysis of Chinese individuals with lamellar cataract, and found that the disorder is associated with inheritance of a 5.11-cM locus on chromosome 16. This locus coincides with one previously described for Marner cataract. We screened individuals of three Chinese families for mutations in HSF4 (a gene at this locus that encodes heat-shock transcription factor 4) and discovered that in each family, a distinct missense mutation, predicted to affect the DNA-binding domain of the protein, segregates with the disorder. We also discovered an association between a missense mutation and Marner cataract in an extensive Danish family. We suggest that HSF4 is critical to lens development.
Amino Acid Sequence↗
A draft sequence of the rice genome (Oryza sativa L. ssp. indica).
We have produced a draft sequence of the rice genome for the most widely cultivated subspecies in China, Oryza sativa L. ssp. indica, by whole-genome shotgun sequencing. The genome was 466 megabases in size, with an estimated 46,022 to 55,615 genes. Functional coverage in the assembled sequences was 92.0%. About 42.2% of the genome was in exact 20-nucleotide oligomer repeats, and most of the transposons were in the intergenic regions between genes. Although 80.6% of predicted Arabidopsis thaliana genes had a homolog in rice, only 49.4% of predicted rice genes had a homolog in A. thaliana. The large proportion of rice genes with no recognizable homologs is due to a gradient in the GC content of rice coding sequences.
Arabidopsis↗
Pharmacokinetics of oxaliplatin (NSC 266046) alone and in combination with paclitaxel in cancer patients.
UNLABELLED: Oxaliplatin (OPT), a third-generation platinating agent, is currently being evaluated in a phase II clinical trial in head and neck cancer patients and in a phase I clinical trial in combination with paclitaxel (TXL). PURPOSE: The aim of this study was to investigate the pharmacokinetics and biological correlates of OPT alone as well as the potential pharmacokinetic interaction between OPT and TXL. METHODS: In the phase II study, OPT was given alone as a 2-h i.v. infusion at 60 mg/m(2) weekly for 4 weeks with the cycle repeated after a 2-week rest. In the concurrent phase I combination trial OPT was also given as a 2-h i.v. infusion, but followed by a 1-h i.v. infusion of TXL, weekly for 4 weeks with the cycle repeated after a 2-week rest. The clinical pharmacokinetics of OPT alone and in combination with TXL were investigated in the first cycle of each treatment protocol. The platinum levels in plasma, plasma ultrafiltrate (PUF) and urine were measured by a fully validated inductively coupled plasma mass spectrometry (ICPMS) method. RESULTS: In the ten patients receiving OPT alone, the concentration-time profiles of total platinum exhibited a biexponential decline both in plasma and in PUF. The peak levels of platinum were 2.72+/-0.41 microg/ml in plasma and 1.36+/-0.42 microg/ml in PUF at the end of the OPT infusion, and the platinum levels were still detectable at >10 ng/ml 94 h after the OPT infusion. The mean terminal t(1/2) values of total platinum in plasma and in PUF were 58.9 h and 22.8 h, respectively. The AUC of ultrafilterable platinum represented about 10% of that of the total plasma platinum. The platinum levels in the DNA fraction of peripheral white blood cells (WBC) correlated with the platinum levels in PUF ( r=0.77, P<0.01). In the phase I combination study, the dose level of OPT was escalated from 35 mg/m(2) to 60 mg/m(2). The concentration-time profiles of platinum in the combination trial also showed biexponential decay in plasma and in PUF as exhibited by OPT alone. However, the terminal elimination rate constant (beta) of total plasma platinum increased at all dose levels of OPT when combined with TXL at 45 mg/m(2) ( P<0.05). A concomitant increase in clearance (CL) of total plasma platinum was observed at the OPT dose level of 45 mg/m(2) in combination with TXL at 45 mg/m(2). No statistically significant difference in the 24-h urinary elimination of total platinum was detected between the combination groups and the single-agent group. The AUC values of total platinum in PUF were proportional to OPT doses ranging from 35 to 60 mg/m(2), whether OPT was given alone or in combination with TXL. CONCLUSIONS: OPT clearance may be enhanced by TXL when the two agents are used in combination in patients. The Pt-DNA adduct level in peripheral WBC was found to be a good indicator for oxaliplatin exposure in patients, and should be further exploited for potential tumor drug exposure.
Antineoplastic Agents↗
In vitro effects of organophosphorus anticholinesterases on muscarinic receptor-mediated inhibition of acetylcholine release in rat striatum.
The aim of the present study was to evaluate the in vitro modulation of muscarinic autoreceptor function by the organophosphorus (OP) anticholinesterases chlorpyrifos oxon, paraoxon, and methyl paraoxon. Acetylcholine (ACh) release was studied by preloading slices from rat striatum with [3H]choline and depolarizing with potassium (20 mM) in perfusion buffer containing hemicholinium-3 (to prevent reuptake of radiolabeled choline). Under these conditions, chlorpyrifos oxon, paraoxon, and methyl paraoxon (0.1-10 microM) all reduced ACh release in a concentration-dependent manner. Addition of the carbamate acetylcholinesterase (AChE) inhibitor physostigmine (20 microM) to the perfusion buffer also decreased ACh release. When physostigmine was present, the three oxons had no additional effect on ACh release. Concentration-dependent inhibition of AChE activity in striatal slices perfused with chlorpyrifos oxon (0.1, 1, and 10 microM) suggested AChE inhibition was responsible for oxon-mediated alterations in ACh release. To differentiate between direct and indirect actions of the OP toxicants on muscarinic autoreceptors, we compared the effects of the oxons on ACh release under two conditions, i.e., tissues were perfused with buffer containing only hemicholinium-3 or with buffer containing hemicholinium-3, physostigmine, and the nonselective muscarinic receptor blocker atropine (100 nM). In the presence of only hemicholinium-3, concentration-dependent inhibition of ACh release was again noted for all oxons, similar to the effects of the muscarinic agonists carbachol and cis-dioxolane. In the presence of physostigmine and atropine, the relative potencies of all agents were markedly reduced. Interestingly, carbachol, cis-dioxolane, paraoxon, and methyl paraoxon all decreased ACh release as before, but chlorpyrifos oxon (100-300 microM) actually increased ACh release. Together, the results suggest that chlorpyrifos oxon, paraoxon, and methyl paraoxon can activate muscarinic autoreceptors indirectly through inhibition of AChE. Both paraoxon and methyl paraoxon also directly activate whereas chlorpyrifos oxon blocks muscarinic autoreceptor function. Qualitative differences in the direct actions of these oxons at this presynaptic regulatory site could contribute to differential toxicity with high-dose exposures.
Acetylcholine↗
The gamma S-crystallin gene is mutated in autosomal recessive cataract in mouse.
We established a recessive cataract model from a spontaneous mutation in the KUNMING outbred mice. Lens opacity appears 11 days after birth. Slit lamp examination reveals that the opacity mainly localizes to the nuclear region of the lens. Histological analysis shows a severe degeneration of the epithelial cells underneath the anterior lens capsule, whereas those cells in the equatorial region display an excessive proliferation and migration. Within the cortical area underneath the posterior lens capsule, both vacuoles and morgagnian-like bodies are seen. Blue-stained spherical bodies are observed in the embryonic nucleus, forming a Y-like pattern. We mapped the disease locus and found a homozygous G to A nucleotide conversion at position 489 of Crygs in mutant mice, leading to a truncated gene product (Trp163Stop). This finding suggests that CRYGS is not only a lens structural protein, but is also likely to be involved in epithelial cell proliferation, apoptosis, and migration.
Animals↗
Age-related effects of chlorpyrifos on muscarinic receptor-mediated signaling in rat cortex.
Chlorpyrifos (CPF) is a widely used organophosphorus pesticide. Earlier work from our laboratory and others has demonstrated that the sensitivity to CPF exposure changes markedly during maturation. A number of studies suggest that in addition to inhibiting acetylcholinesterase (AChE), CPF oxon may also interact directly with m2 and/or m4 subtypes of muscarinic acetylcholine receptors (mAChRs). In the present study, we investigated the in vivo effects of CPF exposure on phosphoinositide (PI) hydrolysis and cAMP formation, second-messenger systems coupled to m1, m3 and m5 (PI hydrolysis) or m2 and m4 (cAMP formation) mAChRs. Neonatal (7-day), juvenile (21-day) and adult (90-day) rats were treated with either peanut oil s.c. or CPF s.c. at 0.3x or 1x the maximum tolerated dosage (MTD: 45, 127 and 279 mg/kg for 7-day, 21-day and 90-day rats, respectively). Neurochemical end-points including AChE activity, muscarinic receptor ([3H]quinuclidinyl benzilate, and [3H]oxotremorine) binding, PI hydrolysis, and cAMP formation in cortex were evaluated at 4 h, 24 h, or 96 h after treatment. Under these conditions, relatively similar maximal degrees of cholinesterase (ChE) inhibition were noted, but times to peak inhibition varied among these age groups (24 h in neonates and juveniles, 96 h in adults). Total muscarinic receptor (QNB) binding was reduced in all three age groups with 1x MTD exposure, at both 24 h and 96 h in neonates and juveniles, but only at 96 h in adults. Oxotremorine binding was also reduced at 96 h after MTD exposure in all three age groups. Neither basal nor carbachol-stimulated IP accumulation was affected in any age group or at any time point following CPF exposure. In contrast, basal cAMP formation was significantly increased by MTD exposure in all three age groups 4 h after exposure, and at 4 h, 24 h, and 96 h after exposure in juveniles. Forskolin/Mn2+-stimulated cAMP formation was increased in neonates and juveniles at 96 h, and in juveniles also at 24 h, but was significantly decreased in adults at 96 h after MTD exposure. Oxotremorine-mediated inhibition of cAMP formation was significantly greater at 96 h after MTD exposure in all three age groups. These results provide further evidence that the cortical cAMP signaling pathway may be particularly sensitive to CPF exposure in neonatal, juvenile, and adult rats, possibly due to a direct interaction between CPF (or its oxon) and mAChRs or other components of the adenylyl cyclase cascade.
Age Factors↗
Numerical studies on the effect of lowering temperature on the oxygen transport during brain hypothermia resuscitation.
There have been arguments about the advantage and shortcoming of hypothermia on the brain resuscitation during circulation arrest. People usually accepted that hypothermia may decrease the cerebral oxygen demands, which is beneficial for the patient to sustain longer time when subjected to a hypoxia. However, there are also quite a few disputes claiming that the blood viscosity would increase with the reduction of temperature, which may lead to an increase of cerebral vascular resistance and thus worsen the hypoxia state. To resolve this critical issue, a heat transfer model was established to characterize the thermal response of brain tissue during hypothermia resuscitation. Combined with this model, a compartmental model taking account of the temperature effect was further developed to analyze the transient oxygen partial pressure (PO(2)) distribution over the successive branches of the vascular network during circulation arrest. Using the morphological and physiological data of a sheep brain, effects of lowering temperature on the oxygen consumption dynamics were studied. Calculations indicated that the lower the temperature, the slower the decreasing rate for the PO(2). Although immediately lowering the brain temperature may induce an evident increase in blood viscosity and subsequently a decrease in blood flow rate, which is responsible for oxygen delivery, it seems to always result in a monotonic increase of PO(2). The results show a good qualitative accord with the experimental data. They also present better understanding on the transient oxygen transport in brain hypothermia during circulation arrest.
Animals↗
Microbial BOD sensors for wastewater analysis.
The field of biosensors for measuring biochemical oxygen demand (BOD) is reviewed. Particularly, BOD sensors constructed on the biofilm configuration are discussed regarding performance characteristics like linearity, response time, precision, agreement between BOD values obtained from the biosensors and the conventional 5-days test, as well as toxic resistance to various compounds and operational stability. The techniques for improving the agreement between the sensor BOD and BOD5 are described. Information provided also includes BOD biosensors based on respirometers and other measuring principles, the commercial BOD instruments, as well as the current limitations of BOD biosensor development.
Biofilms↗
A multicenter, open-label, randomized comparison of levofloxacin and azithromycin plus ceftriaxone in hospitalized adults with moderate to severe community-acquired pneumonia.
BACKGROUND: Changing etiologic patterns and the growing problem of antimicrobial resistance, particularly an increase in macrolide-resistant pneumococcal bacteremia, are causing physicians to adopt new approaches to the treatment of community-acquired pneumonia (CAP). OBJECTIVE: The relative efficacy and tolerability of levofloxacin monotherapy and azithromycin and ceftriaxone combination therapy were assessed in hospitalized adults with moderate to severe CAP. METHODS: This Phase IV, multicenter, open-label, randomized trial compared 2 treatment regimens: (1) levofloxacin 500 mg PO or IV q24h, and (2) azithromycin 500 mg IV q24h for > or = 2 days plus ceftriaxone 1 g IV q24h for 2 days, followed by an optional transition to azithromycin 500 mg PO q24h at the investigator's discretion. The total duration of therapy was to be a minimum of 10 days in both treatment groups. Ceftriaxone was included in the initial azithromycin regimen to ensure coverage against pneumococcal bacteremia. RESULTS: Of 236 patients in the intent-to-treat population, completion or withdrawal information was available for 110 patients in the levofloxacin group and 114 in the azithromycin group. Baseline demographic and disease characteristics were comparable between groups. At the end of treatment, the clinical success rate (cured + improved) in clinically evaluable patients was 94.1% in the levofloxacin group and 92.3% in the azithromycin group. The respective posttherapy microbiologic eradication rates were 89.5% and 92.3%. Levofloxacin was as well tolerated as azithromycin, with an incidence of drug-related adverse events (AEs) for all body systems of 5.3% and 9.3%, respectively. None of the drug-related AEs were considered serious [corrected]. CONCLUSIONS: In this study in hospitalized patients with moderate to severe CAP, levofloxacin monotherapy was at least as effective as a combination regimen of azithromycin and ceftriaxone in providing coverage against the current causative pathogens in CAP. In addition, levofloxacin was as well tolerated as the combination of azithromycin and ceftriaxone.
Adult↗
Numerical study on three-region thawing problem during cryosurgical re-warming.
Knowledge of the temperature transients of biological bodies during cryosurgical re-warming is critical for the survival of healthy tissues. To better understand the mechanisms thus involved, a one-dimensional numerical algorithm based on finite difference method was applied to simultaneously solve the thawing processes occurring in three regions with one thawing, another blood-perfused and the third frozen one sandwiched between them. Two typical surface heatings with heating plate or convective warm water and a spatial heating using microwave were particularly adopted to investigate the advancement of the two phase-change interfaces and the transient temperature field over the tissue. Differences among these results were compared and their implementation for the cryosurgical re-warming were discussed. Parametric studies were performed to explore influences of the blood perfusion, the microwave heating power, the surface heat convection coefficient, and the surface heating temperature to the thermal history of the biological bodies. Taking account of several typical blood re-flow patterns most probably occurred in the originally frozen and then thawed tissues after the two phase change interfaces meet together, four heat transfer equations were proposed to characterize the re-warming behavior of the biological body. Effect of the non-ideal solution property of the living tissues to the transient temperature field during cryo-surgical re-warming was also tested through introducing a simple however intuitive way.
Algorithms↗
High-level expression of the C-terminal hydrophobic region of HCV E2 protein ectodomain in E. coli.
High-level expression of hepatitis C virus (HCV) E2 protein fragments encompassing its C-terminal hydrophobic region (downstream of aa 661) in Escherichia coli has been proven difficult. The extreme hydrophobicity of this region has been suspected to be detrimental to the host. In this work, we found that the C-terminal region (downstream of aa 565) of E2 ectodomain interfered with full-length expression of E2 fragments in E. coli. Nonetheless, when the central region (aa 484-622) of E2 was deleted, full-length protein was efficiently produced. C-terminal region aa 567-700 could not be efficiently expressed individually or as mouse dihydrofolate reductase (DHFR) fusion protein. However, a mutant that emerged in the cloning process was able to express full-length DHFR fusion protein. Sequencing analysis reveals the mutation to be a short frame-shift around the fusion junction, altering aa 568-571 of E2. C-terminal region of E2 ectodomain (aa 567-730) carrying this mutation was successfully expressed as hexa-histidine-tagged protein to a high level. The protein was highly insoluble and was purified under denaturing conditions. The purified protein displayed HCV E2-specific antigenicity in Western blot and specific rabbit antiserum was raised against it. These results demonstrate that hydrophobicity of the C-terminal region of E2 ectodomain is not harmful to E. coli host and has no dominative adverse effect on its bacterial expression. Other nucleotide and/or amino acid sequence properties seem to play a more important role. This finding opens up new possibilities for the development of novel bacterially-derived E2 proteins for research and clinical applications.
Animals↗