Biomedical subjects

Jing Chen

Publications and source records attributed to Jing Chen.

At least 271 records · Page 15Linked to original sources

PubMed2004

[Treatment of advanced malignant solid tumors in children with autologous hematopoietic stem cell transplantation].

OBJECTIVE: To investigate the efficacy of autologous hematopoietic stem cell transplantatation in children with advanced solid tumors. METHODS: Bone marrow was collected from the anterior crista of iliac in both sides in 13 cases while peripheral mononuclear cell was harvested with CS-3000 cell separator in other 15 patients after G-CSF mobilization. Since one of them was suspected to have bone marrow involvement of the neuroblastoma cells, the autograft was purged with CliniMACS based on the CD34 positive selection. Conditioning regimen was CBV protocol (cyclophosphamide + bischloro-nitrosourea, i.e., BCNU + etopside) in two children with Hodgkin's disease and etopside plus carboplatin plus melphalan in others. RESULTS: The number of mononuclear cells collected from bone marrow or peripheral blood was equal to (5.4 +/- 2.1) x 10(8)/kg and (4.1 +/- 1.9) x 10(8)/kg, respectively. Hematopoietic reconstitution was achieved in all patients. Mean time of the neutrophil count recovery to 0.5 x 10(9)/L and mean time of platelet recovery over 2.0 x 10(9)/L were 11.8 +/- 5.7 and 21.0 +/- 9.3 days, respectively. Three units of packed red blood cells and three units of platelet products were transfused in the course of transplantation on average. A total of 12 children developed neutropenic fever and 3 of them had positive blood culture, including staphylococcus epidermal, staphylococcus saprophyte and bacillus subtilis. None of the children died of transplantation-associated complication. One child developed acute renal failure, pulmonary edema and pericardial effusion followed by respiratory distress syndrome. Mechanical ventilation and pulmonary surfactant were used and the patient recovered at last. Another patient developed BCNU associated pulmonary injury, severe pulmonary hypertension and eosinophilosis and recovered after treatment. The mean follow up time was 13 months. Among the 27 children, five died of relapse 5 months after transplantation, and one case of NHL had CNS involvement 3 months after transplantation but has got 17 months of survival till now. The remaining twenty one children were in status of disease-free survival. CONCLUSION: Autologous stem cell transplantation might be effective in the treatment advanced solid tumors in children.

Child↗

PubMed2004

[Analysis of surface electromyography on repetitive lifting task-induced fatigue of back muscles].

OBJECTIVE: Using surface electromyography (SEMG) technique to evaluate repetitive lifting task-induced fatigue of back muscles. METHODS: Thirteen volunteers lifted and lowered an 8 kg weight from floor to waist level for 100 times. Fatigue in the erector spinae muscles was quantified by comparing the frequency content of the EMG signal during static contractions performed before, and immediately after the 100 lifts. RESULTS: EMG average amplitude rose gradually during 100 lifts, the difference was significant at T10 right (P < 0.05) and L3 left (P < 0.01), the difference was not significant at T10 left and L3 right (P > 0.05). The median frequency intercept at T10 right, T10 left, L3 right, L3 left erector spinae muscles decreased by 2.0% (P > 0.05) 10.9% and 29.9% (P < 0.05), 27.9% (P < 0.01), respectively. The mean power frequency intercept decreased by 9% at L3 left erector spinae muscle (P < 0.05), the decrease was not statistically significant at other sites (P > 0.05). CONCLUSION: Repetitive lifting may induce measurable fatigue in the erector spinae muscles. Erector spinae muscle at L3 is more easily fatigued than at T10. Using the median frequency intercept to assess muscle fatigue is more sensitive than using mean power frequency intercept.

Adult↗

PubMed2004

[Preparation and spectra of the complexes of the first series transition metals with diphenic acid].

The ligand diphenic acid has been synthesized and the corresponding complexes of transition metal Co, Ni and Mn with diphenic acid have been prepared and characterized by the elementary analysis, IR spectra and ultraviolet-visible spectra. The results of IR show that the vas and vs of -CO2- in the complexes are lower than those of ligand diphenic acid, which can be explained by the coordinating between metal and ligand. In addition, compared with the complex IR spectra, the IR spectra of ligand became complicated due to the ligand polymerization through hydrogen bond. The UV-Vis spectra show that the ligand has three absorption peaks at 288, 273 and 270 nm, respectively, and these are slightly shifted in the complexes. Because the metal d-d absorption is weak, only in Co(C14H8O4) x 2H2O there is a d-d absorption at 537 nm.

Biphenyl Compounds↗

PubMed2004

[Influence of elevated atmospheric CO2 on rhizosphere microbes and arbuscular mycorrhizae].

The changes of microbial communities in rhizosphere and the formation of mycorrhizae play an important role in affecting the dynamics of plant communities and terrestrial ecosystems. This paper summarized and discussed the effects of elevated atmospheric CO2 on them. Under elevated atmospheric CO2, the carbohydrates accumulated in root systems increased, and the rhizospheric environment and its microbial communities as well as the formation of mycorrhizae changed. It is suggested that the researches in the future should be focused on the effects of rhizosphere microbes and arbuscular mycorrhizae on regulating the carbon dynamics of plant communities and terrestrial ecosystems under elevated atmospheric CO2.

Atmosphere↗

PubMed2004

[Content analysis of bilirubin in niuhuang compound suppository by HPLC].

OBJECTIVE: To establish a method of determinating content of bilirubin in Niuhuang Compound Suppository by HPLC. METHOD: C18 column was used. The mobile phase was consisted of dimethylsulfoxide: acetonitrile: 0.5% acetic ammonium (1:1.4:1). Detector wavelength was 456 nm. The extraction solution for bilirubin was consisted of dlimethylsulfoxide: acetonitrile = 9:4. RESULTS: The linearity was obtained over the range of 0.107 - 2.14 microg. The mean recovery was 101.0%, RSD = 0.518% (n = 5). CONCLUSION: The method was sensitive, simple and accurate.

Animals↗

PubMed2004

[Effects of BCG-PSN on serum levels of IL-4 and IL-12 in patients with condyloma acuminatum].

OBJECTIVE: To determine the effects of polysaccharide nucleic acid fraction of bacillus calmette guerin (BCG-PSN) on serum levels of interleukin-4 (IL-4) and interleukin-12 (IL-12) in patients with condyloma acuminatum (CA) and to investigate the mechamism of immunoregulation of BCG-PSN on CA. METHODS: Sixty CA cases were randomly divided into 2 groups. The serum levels of IL-4 and IL-12 were respectively measured by Double-antibody sandwich ELISA method before and after the treatment. The serum levels of IL-12 and IL-4 of health control were also measured. The recurrent rate of each group was used as an index to assess the effect of BCG-PSN in CA patients. RESULTS: Compared with healthy controls, the serum levels of IL-12 in patients with CA were decreased significantly (P < 0.05), while the serum levels of IL-4 were increased significantly (P < 0.05) before the treatment. The serum levels of IL-12 were negatively correlated with the serum levels of IL-4 (r = -0.287, P < 0.05). After the treatment, the serum levels of IL-12 were increased significantly( P < 0.05), and the serum levels of IL4 were decreased significantly (P < 0.05) in the treatment group. But in the control group, the serum levels of IL-12 and IL-4 were similar before and after the treatment (P > 0.05). The recurrent rate of treatment group was significantly lower than that of the control group (chi2 = 4.356, P < 0.05). CONCLUSIONS: There is an imbalance of Th1/Th2 cytokines production in patients with condyloma acuminatum. BCG-PSN could increase the serum level of IL-12 and decrease the serum level of IL-4 in CA patients. BCG-PSN could decrease the recurrent rate of CA. The effect may be related to the regulation and modulation of BCG-PSN to Thl/Th2 cytokines imbalance,which then enhances the cellular immunity in CA patients.

Adjuvants, Immunologic↗

PubMed2003

Functional reconstruction of rabbit corneal epithelium by human limbal cells cultured on amniotic membrane.

PURPOSE: To investigate the phenotype of fetal and adult human limbal cells cultured on human amniotic membrane and the ability of cultured adult human limbal cells to repair limbal stem cell deficiency in a rabbit model. METHODS: Human adult and fetal limbal cells were isolated and cultured either on plastic plates or on human amniotic membrane. Connexin43, p63, and keratins 3 and 12 (K3 and K12) were detected by immunofluorescence and RT-PCR. Limbal stem cell deficiency was established in rabbits using chemical ablation and mechanical debridement. Cultured adult human limbal cells were transplanted onto rabbit corneas one month after injury, then fixed and imbedded in paraffin forty days later. Immunofluorescent staining of human-nuclear antigen, p63, K3, and connexin43 identified human-specific cells, progenitor cells, and differentiated corneal epithelial cells, respectively. RESULTS: Adult and fetal cultured limbal cells appeared similar in morphology. RT-PCR results showed that cells cultured from the human adult and fetal limbal area expressed both p63 and K12, whereas cells from central adult epithelium expressed K12 only. Immunofluorescent staining showed that more cells were p63 positive when cultured on human amniotic membrane than on plastic. Double staining for p63 and connexin43 showed some p63-positive cells co-expressing connexin43. After transplantation of adult human limbal cells cultured on human amniotic membrane, injured rabbit corneas were completely reconstructed exhibiting epithelial integrity, improved corneal clarity, and little or no neovascularization. The majority of repopulated epithelial cells expressed anti-human nuclear antibody. Cells expressing p63 occurred throughout the new epithelium. CONCLUSIONS: During healing, expression of p63 is not limited to epithelial stem cells but may also mark transient amplifying progenitor cells. Culture on human amniotic membrane suppresses differentiation of limbal epithelial cells and promotes the proliferation of p63 expressing cells. Amniotic membrane-cultured human limbal cells fully reconstructed rabbit corneas having limbal stem cell deficiency, with human cells providing most of the cells of the new epithelium. Expression p63 is distributed throughout the reconstructed tissue.

Amnion↗

PubMed2003

Protein kinase A-induced negative regulation of the corticotropin-releasing hormone R1alpha receptor-extracellularly regulated kinase signal transduction pathway: the critical role of Ser301 for signaling switch and selectivity.

Activation of CRH receptors type 1 (CRH-R1) by CRH or urocortin (UCN) leads to stimulation of multiple G proteins with consequent effects on diverse signaling cascades in a tissue-specific manner. In human myometrium and human embryonic kidney (HEK)293 cells, binding of UCN to CRH-R1alpha receptors activates both the Gs and Gq, leading to activation of the adenylyl cyclase/protein kinase A (PKA) and the phospholipase C/protein kinase C and ERK1/2 signaling pathways, respectively. The overall result of these signals is often unpredictable, as these two signaling pathways can interact in many cellular systems, with either potentiation or inhibition of ERK1/2 activity. In the present studies we investigated potential signaling interactions after stimulation of CRH-R1alpha receptors in human cultured pregnant myometrial cells or HEK293 cells overexpressing recombinant CRH-R1alpha receptors. We found that the adenylyl cyclase/PKA pathway has the capacity to markedly decrease UCN-induced ERK1/2 activation, and that these effects were due in part to the ability of PKA to phosphorylate the CRH-R1alpha at position Ser(301) in the third intracellular loop. Mutant CRH-R1alpha receptors with substitutions at position Ser(301), which is the only potential PKA phosphorylation site, were resistant to PKA-dependent phosphorylation and showed altered signaling characteristics, which were dependent upon the amino acid substitution at this position. We conclude that Ser(301), which is located in the third intracellular loop of CRH-R1alpha, is critical for efficient coupling of the receptor to G proteins and to second messenger generation. Phosphorylation by PKA prevents maximal coupling of the CRH-R1alpha to Gq-protein, and thereby reduces activation of ERK 1/2.

Cells, Cultured↗

PubMed2003

[The clinical characteristics and its relationship with metabolic syndrome in elderly subjects with impaired glucose regulation].

OBJECTIVE: To study the clinical characteristics of impaired glucose regulation (IGR) in elderly subjects and its relationship with metabolic syndrome (MS). METHODS: The exploration of IGR in 2 810 Chongqing citizens over 40 years old was done by OGTT in a cross-section study. Normal glucose tolerance (NGT), IGR and diabetes (DM) were grouped based on the1999 diagnosis standard of WHO. IGR was composed of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and both of which. RESULTS: The prevalence of IGR was 18.11%, among which IGT (85.27%). Compared with the NGT group, the IGR group had higher age, body mass index (BMI), blood pressure, triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-c) and HOMA-IR, lower high density lipoprotein cholesterol (HDL-c) and HOMA-B. The IGR group had lower blood pressure, TG and HOMA-IR, and higher HOMA-B than the DM group. When each subgroup of IGR was compared with each other, both IFG plus IGT subgroup and IFG subgroup had higher BMI and HOMA-IR, and lower HOMA-B than IGT subgroup. The prevalences of hypertension, lipid disorder, obesity/overweight, and microalbuminuria in each subgroup of IGR were statistically higher than that of the NGT group. The prevalence of MS in the IFG plus IGT subgroup was higher than that of the IGT subgroup. CONCLUSIONS: The incidence of IGR was high in elderly people over 40 years old in local district of Chongqing city. There were various metabolic disorders in the subgroups of IGR. The IFG plus IGT and IFG group had higher BMI, hypertension, microalbuminuria and HOMA-IR, but lower HOMA-B than the IGT group.

Aged↗

PubMed2003

[Analysis on GST-Pi genetic polymorphism in children with acute leukemia].

OBJECTIVES: To study the frequency distribution patterns of the genetic polymorphisms for glutathione S-transferase Pi (GST-Pi) in children with acute leukemia, and explore the possible relationship of GST-Pi gene mutation to the vulnerability of children with leukemia and the chemotherapeutic response. METHOD: Direct DNA sequencing was applied to detect the genotype polymorphism in 85 healthy children as the control group and 120 children with acute leukemia. The distribution difference of the genotypes between them was analyzed. RESULTS: Gene mutation rate of GST-Pi exon5 was 47.5% in children with acute leukemia, significantly higher than that of 31.8% in the control group (OR = 1.944, 95% CI 1.088-3.473), and this polymorphism distribution pattern was similar to that reported abroad. The mutation rate was much higher in ALL group than in others groups and was not significantly between the AML children and the control group. The overall mutation rate of B-lineage ALL (60.3%) was markedly higher than that of T-ALL (47.1%), but the homozygous mutation rate of the latter group (17.6%) was much higher than that of the former group (3.4%) (P < 0.05). The average survival time of the children with wild type exon5 was 24 months, longer than that of the mutation group (17.6 months), however with no statistical difference (P > 0.05). The genotype of exon5 had no effect on the survival time of AML children. No Ala(114)Val variant genotype of GST-Pi exon6 reported in literatures was found in this study, but two new mutant genotypes were discovered. A/G hybridity at 99 loci of exon6 was found in one healthy child and such hybrid genotype did not result in amino acid alteration. G-->T/G bases hybridity at 103 loci of exon6 occurred in two children with leukemia, leading to GAC of Asp (aspartic acid) replaced by TAC of Try (tyrosine) at 147 loci of the protein peptide chain, producing Asp(147) Try hybrid mutation with a genotypic frequency of 1.7%. CONCLUSION: The gene mutation of GST-Pi exon5 is one of the potential vulnerable factors in leukemogenesis of the Chinese children and the genetic polymorphism of exon6 in Chinese is greatly different from that in other races. The role of the newly discovered variant genotype Asp(147) Try in leukemogenesis remains to be further studied.

Adolescent↗

PubMed2003

[Production of aldosterone by rat mesangial cell and the accumulation of extracellular matrix induced by aldosterone].

OBJECTIVE: To investigate whether aldosterone (Aldo) may be synthesized by glomerular mesangial cells and whether Aldo promotes the synthesis of fibronectin (FN) and type IV collagen in mesangial cells. METHODS: Rat mesangial cells (RMC) were cultured and then divided into 4 groups: control group, AngII group (AngII of the concentrations of 10(-10), 10(-9), 10(-8), 10(-7), and 10(-6) mol/L was added), losartan group (AngII 1 type inhibitor losartan and AngII were added), and KCL group (KCL of the concentrations of 7 and 9 mmol/L was added). 48 hours after the RNAs of the cells in different groups were collected to detect the Aldo synthesized by the RMCs themselves. Another RMCs were cultured and divided into 4 groups: control group, Aldo group (Aldo of the concentration of 10(-7) mol/L was added), spironolactone + Aldo group (spironolactone 10(-9) mol/L and Aldo 10(-7) mol/L were added), and spironolactone group (spironolactone 10(-9) mol/L was added). RT-PCR was used to detect the expression of the Aldo synthase CYP11B2, mineralocorticoid receptor (MR), and 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD2 (an enzyme required for MR ligand specificity) mRNAs and proteins. The level of Aldo in the incubation medium was detected by radioimmunoassay. After being exposed to 10(-7) mol/L Aldo for 24 h, the level of FN and type IV collagen in the incubation medium were examined by ELISA and Western blotting respectively. RESULTS: CYP11B2, MR, and 11 beta-HSD2 mRNA expressions were detectable in RMCs by RT-PCR and confirmed by sequencing. The concentration of Aldo in the incubation medium was 1.605 pg/10(6) cells. The mRNA expression of CYP11B2 was significantly up-regulated by both AngII and potassium. Immunocytochemistry showed that MR and 11 beta-HSD2 were distributed in both the cytoplasm and the nucleolus. After treatment of 10(-7) mol/L Aldo for 24 hours, the concentration of FN was 74 +/- 16 ng/ml, significantly higher than the baseline value (12.4 +/- 1.9 ng/ml, P < 0.05) and those of spironolactone group and spironolactone + Aldo groups (17.8 +/- 3.6 ng/ml and 25.9 +/- 5.3 ng/ml respectively); and the level of type IV collagen was 136% +/- 14%, significantly higher than the baseline level (100%, P < 0.05), and those of spironolactone group and spironolactone + Aldo groups (112% +/- 33% and 102% +/- 10% respectively). CONCLUSION: RMCs synthesize Aldo. Aldosterone also acts on RMCs, leading to extracellular matrix accumulation AngII and potassium are involved in the regulation of local production of aldosterone.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed2003

The epidermal growth factor receptor tyrosine kinase inhibitor ZD1839 selectively potentiates radiation response of human tumors in nude mice, with a marked improvement in therapeutic index.

PURPOSE: The epidermal growth factor receptor tyrosine kinase inhibitor ZD1839 (Iressa) markedly potentiates the efficacy of many cytotoxic agents against several human cancer xenografts, irrespective of tumor EGFR expression levels. We subsequently investigated the extent to which ZD1839 might improve radiation therapy (RT) in similar animal models of human cancer within the limits of tolerance at a relevant organ site. EXPERIMENTAL DESIGN: We carried out studies of ZD1839 in in vivo models of human non-small cell lung (A549 and SK-LC-16) and breast (MDA-MB468) cancers and human mesothelioma (JMN). The tumors were implanted s.c. over the rib cage or on the most proximate breast and RT given ventral dorsally to the chest only, with mediastinal protection. After the tumor reached a palpable size (0.4-0.6 mm), treatment was initiated with the maximum-tolerated dose (MTD) of ZD1839 (150 mg/kg once daily x 5 for 2 successive weeks), RT (a total of 40 Gy given fractionally at 4 Gy once daily x 5 for 2 successive weeks), or both ZD1839 and RT. RESULTS: This level of RT induced no untoward effects in the mice and was effective (18-72%) in bringing about regression of the tumors with a few complete regressions. ZD1839 alone, given p.o. on the same schedule at its MTD (150 mg/kg), was modestly inhibitory (35-40%) to tumor growth. RT and ZD1839 could be given together at the same doses on the same schedule, resulting in marked regression (50-99%) and a large number of complete regressions of each of the tumors studied. In these studies, the MTD of ZD1839 could be combined with the MTD of RT with no change in schedule or increase toxicity over ZD1839 or RT alone. CONCLUSIONS: ZD1839 significantly enhanced the antitumor action of RT against the test tumors without significant adverse effects, increasing the therapeutic selectively of ionizing radiation in these model systems. These results predict substantial benefits for this multimodality regimen of therapy in patients.

Animals↗

PubMed2003

Structure-activity studies of a series of dipyrazolo[3,4-b:3',4'-d]pyridin-3-ones binding to the immune regulatory protein B7.1.

The interaction of co-stimulatory molecules on T cells with B7 molecules on antigen presenting cells plays an important role in the activation of naive T cells. Consequently, agents that disrupt these interactions should have applications in treatment of transplant rejection as well as autoimmune diseases. To this end, specific small molecule inhibitors of human B7.1 were identified and characterized. Herein, we report the identification of potent small molecule inhibitors of the B7.1-CD28 interaction. In a high-throughput screen we identified several leads that prevented the interaction of B7.1 with CD28 with activities in the nanomolar to low micromolar range. One of these, the dihydrodipyrazolopyridinone 1, was subsequently shown to bind the V-like domain of human B7.1 at equimolar stoichiometry. With this as a starting point, we report here the synthesis and initial in vitro structure-activity relationships of a series of these compounds.

Antigens, Differentiation, T-Lymphocyte↗

PubMed2003

An RND-type multidrug efflux pump SdeXY from Serratia marcescens.

OBJECTIVES: Serratia marcescens, an important cause of nosocomial infections, shows intrinsic resistance to a wide variety of antimicrobial agents (multidrug resistance). Multidrug efflux pumps are often involved in the multidrug resistance in many bacteria. A study was undertaken to characterize the multidrug efflux pumps in S. marcescens. METHODS: The genes responsible for the multidrug resistance phenotype in S. marcescens were cloned into Escherichia coli KAM32, a drug-hypersusceptible strain, for further analysis. RESULTS: We cloned sdeXY genes and determined the nucleotide sequence. Clones that carried the sdeXY genes displayed reduced susceptibility to several antimicrobial agents including erythromycin, tetracycline, norfloxacin, benzalkonium chloride, ethidium bromide, acriflavine and rhodamine 6G. A protein similarity search using GenBank revealed that SdeY is a member of the resistance nodulation cell-division (RND) family of multidrug efflux proteins and SdeX is a member of the membrane fusion proteins. Introduction of sdeXY into E. coli cells possessing tolC, but not in cells lacking tolC, resulted in multidrug resistance. We observed energy-dependent ethidium efflux in cells of E. coli KAM32 possessing sdeXY and tolC. CONCLUSIONS: SdeXY is the first RND-type multidrug efflux pump to be characterized in multidrug-resistant S. marcescens.

Anti-Bacterial Agents↗

PubMed2003

Association of an aminoacyl-tRNA synthetase with a putative metabolic protein in archaea.

Aminoacyl-tRNA synthetases are essential enzymes that catalyze attachment of amino acids to tRNAs for decoding of genetic information. In higher eukaryotes, several synthetases associate with non-synthetase proteins to form a high-molecular mass complex that may improve the efficiency of protein synthesis. This multi-synthetase complex is not found in bacteria. Here we describe the isolation of a non-synthetase protein from the archaeon Methanocaldococcus jannaschii that was copurified with prolyl-tRNA synthetase (ProRS). This protein, Mj1338, also interacts with several other tRNA synthetases and has an affinity for general tRNA, suggesting the possibility of forming a multi-synthetase complex. However, unlike the non-synthetase proteins in the eukaryotic complex, the protein Mj1338 is predicted to be a metabolic protein, related to members of the family of H(2)-forming N(5),N(10)-methylene tetrahydromethanopterin (5,10-CH(2)-H(4)MP) dehydrogenases that are involved in the one-carbon metabolism of the archaeon. The association of Mj1338 with ProRS, and with other components of the protein synthesis machinery, thus suggests the possibility of a closer link between metabolism and decoding in archaea than in eukarya or bacteria.

Amino Acid Sequence↗

PubMed2003

Reversible methionine sulfoxidation of Mycobacterium tuberculosis small heat shock protein Hsp16.3 and its possible role in scavenging oxidants.

Mycobacterium tuberculosis (TB) small heat shock protein Hsp16.3 was found to be a major membrane protein that is most predominantly expressed under oxidative stress and is localized to the thickened cell envelope. Gene knock-out studies indicate that the Hsp16.3 protein is required for TB to grow in its host macrophage cells. The physiological function of Hsp16.3 has not yet revealed. Our analyses via mass spectrometry, conformation-dependent trypsin digestion, nondenaturing pore gradient electrophoresis, ANS-binding fluorescence measurements, and circular dichroism demonstrate that the three and only the three methionine residues (cysteine and tryptophan residues, which can also be readily oxidized by such oxidant as H(2)O(2), are absent in Hsp16.3) can be readily sulfoxidized with H(2)O(2) treatment in vitro, and the methionine sulfoxide can be effectively reduced back to the methionine form. Interconversion between the methionine and methioninesulfoxide has been confirmed by selective oxidation and reduction. The sulfoxidation leads to a small degree of conformational change, which in turn results in a significant decrease of the chaperone-like activity. Data presented in this report strongly implicate that reversible sulfoxidation/desulfoxidation of methionine residues may occur in Hsp16.3, which serves as a way to scavenger reactive oxygen or nitrogen species abundantly present in macrophage cells, thus protecting the plasma membrane and other components of M. tuberculosis allowing their survival in such bacteriocidal hosts.

Bacterial Proteins↗

PubMed2003

Phase I study of a lipooligosaccharide-based conjugate vaccine against nontypeable Haemophilus influenzae.

Nontypeable Haemophilus influenzae (NTHi) accounts for about one-third of purulent otitis media (OM) in children and is a common cause of pulmonary infection in adults with decreased resistance. Based upon sero-epidemiological data in humans and immunochemical data in laboratory animals, a lipooligosaccharide (LOS)-tetanus toxoid (TT) conjugate was prepared and evaluated for its safety and immunogenicity in a Phase I study of 40 healthy adults. The conjugate was injected intramuscularly into all volunteers: 28 of them received a second injection 14 weeks later. Local and systemic reactions were monitored and sera, taken before and 2, 6, 14, 16, and 38 weeks after injection, were assayed for IgG, IgA, and IgM antibodies to the LOS by ELISA and for bactericidal activity. The results indicate that there were no significant local or systemic reactions after either injection. All volunteers had pre-existing IgG anti-LOS. The geometric mean (GM) level rose from 14 to 40 at 2 weeks, remained at 35 at 6 weeks (40 or 35 versus 14, P<0.01) and dropped to 27 at 14 weeks after the first injection. There was also a rise 2 weeks after the second injection (27 versus 37, P<0.05). A total of 52.5% of subjects showed serum-conversion (greater than four-fold increase) after one and two injections. At 38 weeks, the GM IgG anti-LOS was still higher than before initial injection (20 versus 14, P<0.05). A similar pattern of reactivity was observed for IgA and IgM anti-LOS. Similar to that observed in mice, but not in rabbits, the conjugate-induced antibodies did not yield significant bactericidal activity in vitro. The LOS-TT conjugate is well tolerant in adults and a Phase II evaluation of the conjugate in children is planned.

Adult↗

PubMed2003

Mobilization of hematopoietic stem cells during homeostasis and after cytokine exposure.

We created parabiotic mice, joining ROSA26 and PeP3b animals, to study the trafficking of hematopoietic stem cells (HSCs) from marrow to blood and their return to marrow. The transfer of HSCs was assayed by secondary marrow transplantation and was 1.0% to 2.5% after 3, 6, 8, and 12 weeks. Thus, HSC homeostasis is primarily maintained by the retention of stem cells derived from replication events within the marrow, not the homing and engraftment of HSCs from the circulation. Of interest, the phenotypes of marrow progenitors and granulocytes were similar to those for HSCs, implying that the marrow functions as an intact compartment where differentiating cells derive from endogenous HSC. In contrast, 50% of splenic granulocytes and progenitor cells derived from the parabiotic partner, suggesting splenic progenitor cells were in constant equilibrium with progenitors in blood. In additional studies, animals were exposed to granulocyte-colony-stimulating factor (G-CSF) and stem cell factor at days 17 to 20 of parabiosis and were studied 3 weeks later; 10.1% of marrow HSCs derived from the parabiotic partner. These data imply that HSCs, mobilized to the blood in response to cytokine exposure, are destined to later return to marrow, an observation that supports the concept that the mobilized peripheral blood stem cells used in clinical transplantation function physiologically.

Animals↗