The MPN method was used to enumerate ammonia-oxidizing bacteria (AOB) in water and sediments of several shallow lakes. The suitable incubation time, medium types and substrate (ammonium sulphate) concentrations were studied. The results showed that, MPN values increased with the incubation time, reaching a stable maximum at some time stages, which was 40 days in all the samples for MSF medium. Among the three media used (XZ-AOB、MSF、SW), MSF give the highest MPN value. In addition, am- monium sulphate concentration in medium was an important factor affecting MPN estimation of AOB. Compared to AOB in lake sediments, AOB in lake water was more sensitive to ammonium sulphate concentration.

OBJECTIVETo explore the inhibition pathway of the EBV-immortalized cells (CD23(+)) in children with infectious mononucleosis (IM) caused by Epstein-Barr virus.

METHODSThe expressions of CD23, CD19, CD95, Bcl-2 and the co-expressions of CD23CD95, CD19CD23 on peripheral blood mononuclear cell (PBMC) were analyzed by flow cytometry (FCM) during acute phase, early convalescent phase and convalescent phase of 34 EBV-IM children and compared with that of 24 healthy donors.

RESULTS(1) The levels of CD23(+) and CD23(+)CD19(+) cells decreased and CD95(+), CD95(+)CD23(+), Bcl-2(+) cells increased markedly in IM patients in acute phase [CD95(+) cells (19.43 +/- 8.46)%; CD95(+)CD23(+) cells (1.81 +/- 1.71)%; Bcl-2(+) cells (23.41 +/- 26.47)%] and early convalescent phase [CD95(+) cells (12.94 +/- 5.05)%; CD95(+)CD23(+) (1.05 +/- 1.20)%; Bcl-2(+) cells (10.54 +/- 9.68)%], as compared with those of healthy controls [CD95(+) cells (10.39 +/- 2.90)%; CD95(+)CD23(+) cells (0.50 +/- 0.46)%; Bcl-2(+) cells (7.25 +/- 2.88)%]. The earlier the course of IM, the more abnormal the expressive levels. All the abnormal results returned to normal in convalescent phase. (2) Positive relationships were observed between the expressions of CD95(+)CD23(+) cells and that of CD23(+) cells, CD23(+)CD19(+) cells during acute and early convalescent phase, the expressions of Bcl-2(+), CD3(+) cells and CD23(+), CD23(+)CD19(+) cells during acute phase, the expressions of CD95(+)CD23(+) cells and Bcl-2(+) cells during acute phase, and the expressions of CD95(+)CD23(+) cells and CD95(+) cells during convalescent phase.

CONCLUSIONThe results indicate that CD95L-CD95 mediated apoptosis plays an important role in eliminating EBV-immortalized cells, which is counteracted partly by Bcl-2.

Antigens, CD19 ; blood ; Cell Transformation, Viral ; Cells, Cultured ; Child ; Child, Preschool ; Female ; Herpesvirus 4, Human ; Humans ; Infant ; Infectious Mononucleosis ; blood ; pathology ; virology ; Male ; Receptors, IgE ; blood ; bcl-Associated Death Protein ; blood ; fas Receptor ; blood

OBJECTIVEEpstein-Barr virus (EBV) is a common causative agent of infectious mononucleosis (IM) and capable of efficiently immortalizing primary B cells into continuously growing lymphoblastoid cells in vitro. As B cell activation antigen, CD23 expression is induced by EBV infection of B cells and remains constitutively expressed at high levels in virtually all EBV-immortalized cells, which have been strongly linked to the development of B-cell lymphoproliferative disease and lymphoma. Whereas previous studies were performed in vivo in animals or ex vivo cultures, the present study aimed to explore the role of EBV-immortalized cells (CD23(+)/CD19(+)) in vivo analysis of children with EBV-IM.

METHODSIn a prospective trial, a group of 30 patients with IM (18 boys and 12 girls) with mean age of 3.9 +/- 1.3 years (range 6 months to 8 years) were enrolled. Clinical diagnosis of IM was confirmed based on fever, lymphadenopathy, splenomegaly, lymphocytosis (> 50%), atypical lymphocytes (> 10%) in blood smears and the elevated levels of IgM antibody against EBV capsid antigen. The day of onset of fever was recognized as day 1 of illness. Blood samples taken during acute (3 - 5 days), early convalescent (about 11 - 15 days) and convalescent phase (about 30 - 45 days) were analyzed for expressions of CD19(+)/CD23(+), CD23, CD19 on peripheral blood mononuclear cells by flow cytometry (FCM) and was compared with those of control group.

RESULTS(1) The levels of CD23(+)/CD19(+) and CD23 expressions were markedly decreased in acute stage [CD23(+)/CD19(+) (2.22 +/- 1.47)%, (132 +/- 91)/mm(3); CD23 (3.12 +/- 1.88)%, (195 +/- 102)/mm(3)] and in early convalescent stage [CD23(+)/CD19(+) (4.51 +/- 2.25)%, (166 +/- 85)/mm(3); CD23 (5.55 +/- 2.76)%, (231 +/- 130)/mm(3)] in patients with IM as compared with those of the healthy controls [CD23(+)/CD19(+) (6.71 +/- 2.25)%, (215 +/- 68)/mm(3); CD23 (7.85 +/- 3.09)%, (249 +/- 86)/mm(3), respectively]. The earlier the history was, the lower the expressive levels were. The levels of CD23(+)/CD19(+) expressions returned to, but those of CD23 expressions exceeded, normal level in convalescent stage [CD23(+)/CD19(+) (6.72 +/- 2.16)%, (213 +/- 108)/mm(3); CD23 (9.46 +/- 2.73)%, (366 +/- 200)/mm(3)]. (2) There was a positive correlation in the expressions of CD23(+)/CD19(+) and CD23 among the three stages (P < 0.01). The positive correlation between the expressions of CD23(+)/CD19(+) and CD19 only occurred during acute stage (P < 0.01). There was no correlation between the expressions of CD23 and CD19 (P > 0.05).

CONCLUSIONEBV-immortalized cells and CD23(+) cells were inhibited effectively during the acute and early convalescent stage of IM. With the recovery of the disease, they gradually recovered and the levels of CD23 expressions exceeded normal level in convalescent stage.

B-Lymphocytes ; metabolism ; Cell Culture Techniques ; Cell Survival ; Child ; Child, Preschool ; Female ; Herpesvirus 4, Human ; pathogenicity ; Humans ; Infant ; Infectious Mononucleosis ; metabolism ; Male ; Receptors, IgE ; metabolism

OBJECTIVEInfectious mononucleosis (IM) is a lymphoproliferative disease caused primarily by the Epstein-Barr virus (EBV) infection. The initial viral infection by EBV occurs in B lymphocytes and is followed by an extensive proliferation of T lymphocytes. Previous studies on immunity to EBV (including IM) have mainly focused on activation of peripheral blood T cells, which are responsible for the lymphocytosis in blood during acute IM. B cells, regarding CD23 as their activation marker, are the target cells of EBV infection. There are few reports on their effect in patients with IM. The role of them during acute IM is not known yet. The present study aimed to explore the action of B cells in patients with IM.

METHODSIn a prospective trial, a group of subjects comprised 22 patients with IM (14 boys and 8 girls) with mean age of 3.48 +/- 0.81 years (range 7 months to 8 years). Clinical diagnosis of IM was confirmed based on fever, lymphadenopathy, splenomegaly, lymphocytosis (> 50%), atypical lymphocytes (> 10%) in blood smears and the elevated levels of IgM antibody against EBV capsid antigen. The day of onset of fever was recognized as day 1 of illness. Blood samples taken during acute (3 - 5 days) and convalescent phase (about 15 days) were analyzed for expressions of CD19, CD19(+)/CD23(+) on PBMC by flow cytometry (FCM) and was compared with those of control group. The number of the days with fever was recorded.

RESULTS(1) The levels of CD19 and CD19(+)/CD23(+) expressions were markedly decreased in acute stage [CD19 (5.63 +/- 2.91)%, (387 +/- 178)/mm(3), CD19(+)/CD23(+) (2.45 +/- 1.87)%, (160 +/- 99)/mm(3)] and in convalescent stage [CD19 (12.49 +/- 5.70)%, (428 +/- 156)/mm(3), CD19(+)/CD23(+) (5.05 +/- 2.79)%, (172 +/- 78)/mm(3)] in patients with IM as compared with those of the healthy controls [CD19 (16.20 +/- 2.80)%, (545 +/- 150)/mm(3); CD19(+)/CD23(+) (7.08 +/- 2.78)%, (249 +/- 136)/mm(3)]. The earlier the specimens were taken after onset, the lower the expressed levels were. (2) There was a positive correlation of the expressions of CD19 and CD19(+)/CD23(+) between acute and convalescent stage (P < 0.01);there was also a positive correlation between the expressions of CD19 and CD19(+)/CD23(+) during acute and convalescent stage (P < 0.01). (3) A negative correlation was found between the duration of fever and the level of CD19 and CD19(+)/CD23(+) in acute stage (P < 0.01).

CONCLUSIONThe results indicate that B cells and CD23(+) B cells were significantly inhibited during the onset of IM in the patients, that with the recovery of the disease, the condition was gradually improved, and that the more evidently the CD19 and CD19(+)/CD23(+) decreased, the more serious the clinical symptoms were and the longer time the recovery needed. The levels of CD19 and CD19(+)/CD23(+) expressions may be useful in diagnosis and predicting the severity.

Antigens, CD19 ; immunology ; B-Lymphocytes ; immunology ; Child ; Child, Preschool ; Female ; Herpesvirus 4, Human ; Humans ; Infant ; Infectious Mononucleosis ; diagnosis ; immunology ; virology ; Male ; Prospective Studies ; Receptors, IgE ; immunology ; T-Lymphocytes ; immunology

This study was aimed to investigate the changes of reactive oxygen species and antioxidative capacity on nitric oxide induced apoptosis in HL-60 cells. By means of in vitro incubation of HL-60 cells with sodium nitroprusside (SNP), the growth inhibition was detected by MTT assay. Cell morphology was observed by transmission electronmicroscopy and light microscopy. The apoptosis was analyzed by DNA agarose gel electrophoresis, DNA content and Annexin-V/PI labeling method. Reactive oxygen species (ROS) labeled with dihydrorhodamin 123 in cells was determinated by flow cytometry. The SNP-treated cells were examined for glutathione (GSH) level and activity of catalase (CAT), glutathione S-transferase (GST) and glutathione peroxidase (GPX). The results indicated that SNP could inhibit HL-60 cell growth. Cell apoposis was confirmed by typical cell morphology, DNA fragment, sub-G(1) phase and Annexin-V/PI labeling method. HL-60 cell apoptosis was induced by SNP in a dosage- and time-dependent manner. After exposing to SNP at the concentration of 0.5 - 3.0 mmol/L for 48 hours, the mean fluorescence intensity of ROS in cells was significantly higher than those in groups control and potassium ferricyanide (PFC). During the apoptosis process, level of ROS in cells increased, levels of GSH, CAT, GPTand GPX decreased. The significant dose-effect relationship existed between the levels of ROS, CAT, GST, GPX and SNP dose. It is concluded that change of intracellular reactive oxygen species and antioxidative capacity are an important factors during the process of SNP-induced apoptosis in HL-60 cell.
Antioxidants ; metabolism ; Apoptosis ; drug effects ; Cell Nucleus ; drug effects ; ultrastructure ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; HL-60 Cells ; Humans ; Microscopy, Electron ; Nitric Oxide Donors ; pharmacology ; Nitroprusside ; pharmacology ; Reactive Oxygen Species ; metabolism

Abnormalities, Multiple ; epidemiology ; Adolescent ; Child ; Child, Preschool ; Heart Defects, Congenital ; complications ; Humans ; Infant ; Infant, Newborn

OBJECTIVETo investigate the antimicrobial resistance and penicillin resistance-associated genes (TEM and pbp2B) of Streptococcus pneumoniae (S. pneumoniae) isolated from sputum specimens of Guangzhou children with respiratory tract infection.

METHODSE-test and Kirby-Bauer methods were applied to detect the antibiotic susceptibility of 44 strains of S. pneumoniae. PCR was used to detect resistance genes pbp2B and TEM, followed by DNA sequence analysis of pbp2B gene. The sequence results were compared to those of penicillin-susceptible S. pneumoniae R6.

RESULTSOf the 44 isolates of S. pneumoniae, only 5 (11.4%) were susceptible to penicillin. All strains were resistant to erythromycin but susceptible to ofloxacin and vancomycin. The resistance rate of the isolates to clindamycin and trimoxazole was more than 90%. The S. pneumoniae isolates showed a high susceptibility to amoxicillin, imipenem and ceftriaxone, with a resistance rate of 0, 2.6% and 3.9%, respectively. The sequence analysis showed that more than 99% nucleotide sequence of pbp2B gene of five penicillin-susceptible isolates was the same as penicillin-susceptible S. pneumoniae R6, without any amino acid replacement. Site mutation was found in the remaining 39 penicillin-nonsusceptible isolates with a nucleotide mutation rate ranging from 13.2% to 23.1% and amino acid replacement rate from 6.5% to 10.9%. The 39 penicillin-nonsusceptible isolates were classified into 4 types according to the mutation site between Ser391 and Thr492 of pbp2B: type I (n=30), type II (n=7), type III (n=1) and type IV (n=1). No TEM gene was detected in all the 44 S. pneumoniae isolates.

CONCLUSIONSThe S.pneumoniae isolates from Guangzhou children with respiratory tract infection are resistant to penicillin and erythromycin. Amoxicillin and the third generation cephalosporin may be recommended for treating S. pneumoniae infection. The mutation of pbp2B gene plays an important role in the development of S. pneumoniae resistance to penicillin.

Aminoacyltransferases ; genetics ; Child, Preschool ; Drug Resistance, Bacterial ; genetics ; Female ; Humans ; Infant ; Male ; Microbial Sensitivity Tests ; Penicillin Resistance ; genetics ; Penicillin-Binding Proteins ; genetics ; Respiratory Tract Infections ; microbiology ; Streptococcus pneumoniae ; drug effects ; genetics ; beta-Lactamases ; genetics

OBJECTIVETo investigate the incidence of campylobacter jejuni (CJ) infection and the drug resistance of CJ in children with diarrhea in Guangzhou.

METHODSThe fecal samples of 3,351 children with diarrhea between July 2005 and June 2008 were collected for CJ culture. The species of CJ strains were identified by Lior methods. The drug susceptibility tests were performed by the Kirby-Bauer method.

RESULTSTwo hundred and sixty-seven CJ strains (8.0%) were isolated from 3,351 samples. The children at age of 1 month to 1 year were susceptible to CJ, accounting for 91.0%. A higher incidence of CJ infection (76.8%) was found in summer and autumn. The CJ strains were susceptible to imipenem, amikacin, cefoperazone/sulbactam, chloramphenicol, macrolides and lincomycins. Parts of CJ strains (20%-40%) were resistant to ampicillin, quinolones and ambramycin. All CJ strains were resistant to sulfamethoxazole/trimethoprim and cefditoren. Two hundred and one strains (75.3%) were CJ biotype I.

CONCLUSIONSCJ is an important pathogen of diarrhea in children from Guangzhou. CJ is resistant to some antibiotics used often in clinical practice, and so it is thus important to use antibiotics based on the results of drug susceptibility tests in children with CJ infection.

Campylobacter Infections ; microbiology ; Campylobacter jejuni ; classification ; drug effects ; isolation & purification ; Child, Preschool ; Diarrhea ; microbiology ; Female ; Humans ; Infant ; Male ; Microbial Sensitivity Tests

To study the molecular mechanisms of nitric oxide donor sodium nitroprusside (SNP) -induced apoptosis in K562 human leukemia cell line, the different concentrations of SNP and different time of culture were used to treat K562 cell. At the same time, potassium ferricyamide (PFC) was used as control, blank was designed in experiment. Cell apoptosis was analysed by cell morphology, DNA agarose gel electrophoresis, DNA content, and annexin-V/PI labeling method. The TdT-mediated dUTP nick end labeling (TUNEL) assay was used to quantify in situ cell apoptosis. Reactive oxygen species (ROS) in cells and mitochondrial transmembrane potential (DeltaPsim) were labeled by dihydrorhodamin 123, 2', 7'-dichlorodihydrofluorescein diacetate and rhodamin 123/PI. bcl-2, bax, bad, p53 gene proteins and mitochondrial membrane protein were analysed by flow cytometry. The results showed that the K562 cell apoptosis was confirmed by typical cell morphology, DNA fragment, sub-G(1) phase, TUNEL and annexin-V/PI labeling. A majority of K562 cells were arrested in G(0)/G(1) phase. During the process of SNP-induced apoptosis in K562 cell, the mean fluorescence intensity of ROS in cells was significantly higher than those in blank and PFC control, while the DeltaPsim reduced. The expression of p53, bax, bad, Fas protein and mitochondrial membrane protein increased and bcl-2 protein decreased after SNP treatment. It is concluded that SNP induces K562 cell apoptosis through increasing ROS in cells, expressing the p53, bax, bad, Fas protein and mitochondrial membrane protein and decreasing bcl-2 protein, opening the mitochondrial permeability transition pore and reducing DeltaPsim. Furthermore, the Fas was activated during the apoptosis process.
Apoptosis ; drug effects ; Dose-Response Relationship, Drug ; Humans ; In Situ Nick-End Labeling ; K562 Cells ; Membrane Potential, Mitochondrial ; drug effects ; Nitric Oxide Donors ; pharmacology ; Nitroprusside ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Reactive Oxygen Species ; metabolism ; Tumor Suppressor Protein p53 ; metabolism ; bcl-2-Associated X Protein ; metabolism ; fas Receptor ; biosynthesis

OBJECTIVETo evaluate the clinical outcome and the effects of treating peri-implantitis with periocline.

METHODSThirty-two sites in 32 implants with peri-implantitis were treated with periocline. The parameters including plaque index, probing depth (PD) of pocket, sulcular bleeding index (SBI) were measured at baseline, 1, 3, 6 and 12 weeks after treatment and followed up for 6 months.

RESULTSStatistically significant decrease (P < 0.05) in SBI, and PD occurred at all time intervals compared to baseline. The treatment could last for at lest four weeks in peri-implantitis cases without fistula.

CONCLUSIONSPeriocline could be safely and effectively used in treating peri-implantitis in cases without peri-implant fistula. Peri-implantitis with fistula should be treated in combination with surgical methods, and periocline can also be used to control inflammation before surgery.

Adult ; Anti-Bacterial Agents ; therapeutic use ; Dental Implantation, Endosseous ; adverse effects ; Dental Implants ; adverse effects ; Female ; Humans ; Male ; Middle Aged ; Minocycline ; therapeutic use ; Periodontitis ; drug therapy ; etiology