The detection and clinical features of human cytomegalovirus infection in infants.

The aim is to investigate the spectrum of disease in 378 infants with human cytomegalovirus infection. In these patients, 27.78% were systemic infection and 72.22% involved single organ infection. Hepatitis, thrombocytopenic purpura, pneumonia were predominant with 33.07%, 13.49%, 6.35% respectively. The rate of HCMV systemic infection in infants younger than 2 weeks was higher than in those older than 2 weeks. The gB genotype analysis in 107 cases showed 53 gBI, 20 gBII, 18 gBIII, 7 gBI+gBII, 5 gBI+gBIII and 4 gBII+gBIII. These results suggest that HCMV can infect multiorgan and has varietal clinic feature. The gBI genotype is most prevalent.

The change of asthma-associated immunological parameters in children with Mycoplasma pneumoniae infection.

BACKGROUND: Mycoplasma pneumoniae (M. pneumoniae), an atypical pathogen, is increasingly recognized as a common and important pathogen. Previous studies showed that M. pneumoniae infection may play a role in asthmatic mechanisms based on evidence collected from peripheral blood or sputum of patients or animal models. However, evidence reported from the airways of patients has been rare. OBJECTIVE: To estimate the role of M. pneumoniae infection in asthma by measuring the immunological parameters from peripheral blood and bronchoalveolar lavage fluid (BALF) in pediatric patients with mycoplasma pneumonia. METHODS: A total of 30 patients with mycoplasma pneumonia and 37 patients without M. pneumoniae infection undergoing fiberoptic bronchoscopy were reviewed. The peripheral blood cell count, immunoglobulins (Ig), BALF cell count, and other clinical and laboratory data were reviewed and analyzed. RESULTS: There were significantly more patients with raised basophil counts in the M. pneumoniae group than that in the control group (p = 0.033). Serum immunoglobulin (Ig) A, IgM, and IgG levels in the M. pneumoniae group were significantly higher than those in the control group (p = 0.008, p = 0.011, and p = 0.019, respectively). The percentage of eosinophils in BALF cells was in the range 0 to 10% in M. pneumoniae patients, while it ranged between 0 and 4% in the control group with a significant difference (p = 0.043). In the M. pneumoniae group, we found that the percentage of eosinophils in the BALF cells was positively correlated with age, the percentage of peripheral eosinophils, and BALF lymphocytes (r = 0.298, p = 0.030; r = 0.341, p = 0.014; r = 0.387, p = 0.006; respectively) and negatively correlated with total peripheral white blood cell (r = -0.387, p = 0.005). CONCLUSION: These results suggest that M. pneumonia infection is associated with the asthma mechanism, especially in older children.

Deletion analysis of SMN1 and NAIP genes in Southern Chinese children with spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a disorder characterized by degeneration of lower motor neurons and occasionally bulbar motor neurons leading to progressive limb and trunk paralysis as well as muscular atrophy. Three types of SMA are recognized depending on the age of onset, the maximum muscular activity achieved, and survivorship: SMA1, SMA2, and SMA3. The survival of motor neuron (SMN) gene has been identified as an SMA determining gene, whereas the neuronal apoptosis inhibitory protein (NAIP) gene is considered to be a modifying factor of the severity of SMA. The main objective of this study was to analyze the deletion of SMN1 and NAIP genes in southern Chinese children with SMA. Here, polymerase chain reaction (PCR) combined with restriction fragment length polymorphism (RFLP) was performed to detect the deletion of both exon 7 and exon 8 of SMN1 and exon 5 of NAIP in 62 southern Chinese children with strongly suspected clinical symptoms of SMA. All the 32 SMA1 patients and 76% (13/17) of SMA2 patients showed homozygous deletions for exon 7 and exon 8, and all the 13 SMA3 patients showed single deletion of SMN1 exon 7 along with 24% (4/17) of SMA2 patients. Eleven out of 32 (34%) SMA1 patients showed NAIP deletion, and none of SMA2 and SMA3 patients was found to have NAIP deletion. The findings of homozygous deletions of exon 7 and/or exon 8 of SMN1 gene confirmed the diagnosis of SMA, and suggested that the deletion of SMN1 exon 7 is a major cause of SMA in southern Chinese children, and that the NAIP gene may be a modifying factor for disease severity of SMA1. The molecular diagnosis system based on PCR-RFLP analysis can conveniently be applied in the clinical testing, genetic counseling, prenatal diagnosis and preimplantation genetic diagnosis of SMA.

[Association between clinical manifestations of infants with human cytomegalovirus infection and glycoprotein B genotype].

OBJECTIVE: To investigate the association between the clinical manifestations of infants with human cytomegalovirus (HCMV) infection and glycoprotein B (gB) genotype. METHODS: Urine samples were obtained from 107 symptomatic infants with HCMV infection confirmed by fluorescence quantitative PCR, 70 male and 37 female, aged 5 d-8 months, and 25 asymptomatic infants with HCMV infection, 16 male and 9 female, aged 21 d-7 months. A fragment of glycoprotein B gene was amplified by nested PCR (nPCR). HCMV gB genotyping was carried out by restriction fragment length polymorphism (RFLP), and some of the amplified DNA fragments were verified by DNA sequencing. RESULTS: Of the HCMV specimens from 107 infants, 53 were typed as gB group I, 20 as gB II, 18 as gB III, 7 as gB I and gB II, 5 as gB I and gB III, and 4 as gB II and gB III, and gB IV was not found. The HCMV gB genotype from 53 infants with hepatic function damage showed that 36 were classified as gB I, 5 as gB II, 7 as gB III, 3 as gB I and gB II, and 2 as gB I and gB III. The gB I genotype was more common among the infants with hepatic function damage (P < 0.05). The distribution of gB genotype in the asymptomatic infants was as follow: gB I, 10/25; gB II, 6/25; gB III, 8/25; and gB I and gB II, 1/25. The homology of PCR products of HCMV gB in 24 strains amplified compared with the sequences of prototype strains in GenBank was from 97.06% to 99.64%. CONCLUSION: RFLP analysis of HCMV gB genotype is definite and reliable. The gB I genotype is more common among the infants with hepatic function damage.

Activation of ATP-sensitive potassium channels prevents the cleavage of cytosolic mu-calpain and abrogates the elevation of nuclear c-Fos and c-Jun expressions after hypoxic-ischemia in neonatal rat brain.

The purpose of this study was to determine whether activation of ATP-sensitive K+ (KATP) channels with diazoxide (DIZ) is able to prevent the cleavage of cytosolic mu-calpain and abrogate the elevation of nuclear c-Fos and c-Jun protein (c-Fos, c-Jun) expressions after hypoxic-ischemia (HI) in brain. The model of hypoxic-ischemic brain injury (HIBI) was made in the 7-day-old Sprague-Dawley (SD) rats by left carotid arterial ligation and hypoxia (8% oxygen). DIZ was injected into the left lateral ventricle (5 microl, 1 mg/ml) before or post-hypoxic-ischemia (HI) insults. Western blot and computer image processing were used to detect the integrated density of nuclear c-Fos and c-Jun at 4 h and cleavage of cytosolic mu-calpain at 24 h after HI insults from cerebral cortical and hippocampal samples. Compared with HI controls (c-Fos=30.37+/-7.39 from cortical samples, 58.61+/-3.64 from hippocampal samples; c-Jun=52.48+/-14.23 from cortical samples, 35.55+/-4.73 from hippocampal samples), there was a significant down-regulation of c-Fos and c-Jun expressions from cortical and hippocampal samples in rats treated with DIZ before (c-Fos=11.10+/-4.64 from cortical samples, 4.82+/-3.38 from hippocampal samples; c-Jun=19.01+/-5.29 from cortical samples, 35.55+/-4.73 from hippocampal samples) or post- (c-Fos=18.81+/-7.93 from cortical samples, 11.33+/-7.05 from hippocampal samples; c-Jun=24.64+/-10.01 from cortical samples, 19.75+/-3.47 from hippocampal samples) HI insults. Furthermore, the ratio of 76 kD/80 kD of mu-calpain was down-regulated from cortical and hippocampal samples in rats treated with DIZ before or post-HI insults, demonstrating a significant difference compared with that observed in HI controls. Finally, the increase in DNA fragments caused by the HI injury was decreased or eliminated by the treatment with DIZ. These data suggests that activation of KATP channels by DIZ reduces the degree of mu-calpain proteolysis, and c-Fos and c-Jun expressions in immature brain may contribute to the neuroprotection of K(ATP) channel openers against HIBI.

Effects of IGF-II on promoting proliferation and regulating nitric oxide synthase gene expression in mouse osteoblast-like cell.

OBJECTIVE: To investigate the effects of insulin-like growth factor II (IGF-II) on promoting cell proliferation, regulating levels of cellular nitric oxide (NO) and mRNA transcriptions of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) in mouse osteoblast-like cells. METHODS: Mouse osteoblastic cell line MC3T3-E1 was selected as the effective cell of IGF-II. After the cells were treated with IGF-II at different concentrations for different time duration, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay was used to examine cell proliferation, and nitrate reductase method was applied to detect NO concentrations in cell culture supernatants and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to determine transcription levels of cellular iNOS and eNOS mRNAs. RESULTS: After the MC3T3-E1 cells were treated with IGF-II at concentration of 1 ng/ml for 72 h, 10 and 100 ng/ml for 24, 48 and 72 h respectively, all the MTT values increased (P<0.05 or P<0.01) with obvious dosage-time dependent pattern. NO levels of the MC3T3-E1 cells treated with 100 ng/ml IGF-II for 48 h, and with 1, 10 and 100 ng/ml IGF-II for 72 h were remarkably lower than that of the normal control, respectively (P<0.05 or P<0.01). After the cells were treated with 100 ng/ml IGF-II for 48 h cellular iNOS mRNA levels were significantly decreased (P<0.01). But the levels of eNOS mRNA in the cells treated with each of the used IGF-II dosages for different time duration did not show any differences compared with the normal control (P>0.05). CONCLUSION: IGF-II at different concentrations could promote proliferation of mouse MC3T3-E1 cell. This cell proliferation promotion was associated with the low NO levels maintained by IGF-II. Higher concentration of IGF-II could down-regulate iNOS gene expression at the level of transcription but not affect transcription of eNOS mRNA, which might be one of the mechanisms for IGF-II maintenance of the low NO levels in MC3T3-E1 cells.

[Determination of six major human herpes viruses in cerebrospinal fluid and blood of children with consensus primers].

OBJECTIVE: To identify 6 major human herpesviruses with consensus primers and to explore its clinical application. METHODS: Based on the highly-homogeneous regions of DNA polymerase gene in human herpesviruses,Two pairs of primer were synthesized. One pair was designed to amplify herpes simplex virus type 1, type 2, Epstein-Barr virus and cytomegalovirus; and another was used to amplify varicella-zoster virus or human herpesvirus 6. Virus species identification was performed by restriction enzyme digestion with BamH I and BstU I. Thirty-eight CSF specimens of clinically diagnosed viral encephalitis,and 49 blood specimens from 27 confirmed cases and 22 clinically diagnosed ones were tested for herpes virus DNA using the PCR-RFLP assay with these primers. RESULTS: Thirteen out of 38 CSF specimens (34.2%) were herpes virus positive. All blood specimens from 27 confirmed cases showed positive results, while for 22 clinically diagnosed cases 16 (72.7%) were positive. The types of herpes virus were determined using restriction enzyme digestion with BamH I and BstU I. Two CSF specimens from the patients, who were treated with aciclovir for 2 - 3 days, were still positive for herpes virus DNA by this method. None of the control blood or CSF controls were positive for herpesvirus by PCR. CONCLUSION: The PCR-RFLP method used in this study is a specific, sensitive and practicable one for diagnosis of herpes virus infection.

[Anti-inflammation and anti-oxidation effects of recombinant human superoxide dismutase on acute lung injury induced by meconium aspiration in infant rats].

OBJECTIVE: To investigate the anti-inflammation and anti-oxidation effects of recombinant human CuZn superoxide dismutase(rhSOD) on acute lung injury (ALI) induced by meconium aspiration in rats. METHODS: 1 ml/kg of 20% human newborn meconium suspension was intratracheally (IT) administrated to induce the model of ALI in 32 male Sprage-Dawley rats, and the animals were then randomized to 4 groups: 3 treatment groups with IT administration of 5, 10 and 20 mg/kg rhSOD dissolved in 1 ml/kg saline and the control group with IT administration of 1 ml/kg saline. The animals were killed after 24 h of treatments. The measurements included lung tissue wet/dry ratio, broncho-alveolar lavage fluid (BALF) protein, BALF protein/plasma protein (pulmonary permeability index, PPI),lung myeloperoxidase (MPO) and superoxide dismutase (SOD) activity, nitric oxide (NO) and 8-isoprostane levels. Lung injury score was also evaluated. RESULTS: Compared with the control group, pulmonary MPO activity, NO and 8-isoprostane levels were significantly decreased and SOD activity was markedly increased in all rhSOD treatment groups (P<0.05 or 0.01). Compared with the rhSOD 5 mg/kg group, pulmonary 8-isoprostane level was further low in the rhSOD 20 mg/kg group(P=0.01). Lung injury score was decreased in rhSOD 20 mg/kg group (P<0.05). But there were no statistically differences in lung wet/dry, BALF protein and PPI among all groups. CONCLUSION: The results suggest that a single IT dose of 5,10 or 20 mg/kg rhSOD can prevent lung damages in rats with ALI following meconium aspiration.

Effect of diazoxide on regulation of vesicular and plasma membrane GABA transporter genes and proteins in hippocampus of rats subjected to picrotoxin-induced kindling.

Epileptiform discharges and behavioral seizures may be the consequences of excess excitation from inadequate inhibitory effects associated with gamma-aminobutyric acid (GABA). GABA is taken up and accumulated in synaptic vesicles by the action of vesicular GABA transporter (VGAT) before its release into the synaptic cleft, and removed from synaptic regions by the action of transporter proteins GABA transporter-1 (GAT-1) and GABA transporter-3 (GAT-3). In this experiment, the effects of diazoxide (DIZ) on the VGAT, GAT-1 and GAT-3 mRNA and protein levels in hippocampus, and on the seizure activities of picrotoxin (PTX)-induced kindling rats were observed. DIZ caused increase in the quantity of VGAT mRNAs and proteins, and down regulation of GABA transporters GAT-1 and GAT-3 mRNAs and proteins after the PTX re-kindling. Furthermore, DIZ produced not only a prompt but also a later suppression of PTX-induced seizures. Although DIZ has effects on ATP-sensitive potassium (K(ATP)) channels when measured in vitro, our study suggests that additional mechanisms of action may involve the regulation of GABA transporters, which may aid in understanding epileptogenesis and inform investigators about future design and development of K(ATP) channel openers to treat epilepsy.

[Influence of different DNA extractions on the identification of streptococcus sanguis group by arbitrary primed polymerase chain reaction]

OBJECTIVE: To assess the influence of different DNA extractions on the identification of streptococcus sanguis group (SSG) species by arbitrary primed polymerase chain reaction (AP-PCR). METHODS: AP-PCR was used to distinguish SSG species by designing 25bp arbitrary primer 5'AAG AGA GGA GCT AGC TCT TCT TGG A 3', and the genomic DNA was extracted by 3 methods. RESULTS: There were great differences in the main band of DNA polymorphism among SSG species. The similar band could be got from the different DNA extractions in the same species. CONCLUSION: Different DNA extractions have no influence on the identification of SSG.

[Effect of adriamycin on sarcoplasmic reticulum Ca2+ -ATPase activity in cardiomyocyte of rabbits]

OBJECTIVE: To evaluate influences of regular-dose of adriamycin (ADR) on heart function and sarcoplasmic reticulum (SR) Ca2+ -ATPase in cardiomyocyte of rabbits. METHODS: Nine rabbits received intraveneous injection of ADR (2mg/kg) once a week for 8 weeks, the rabbits injected with saline were used as control group. Cardiac output (CO), blood pressure (BP), mean artery pressure (MAP), left ventricular systolic pressure( LVSP), left ventricular end-diastolic pressure (LVEDP), calcium in cardiomyocyte (MyoCa2+) of rabbits and SR Ca2+ -ATPase activity were examinated 3 weeks after the final injection. RESULTS: CO, LVSP and SR Ca2+ -ATPase activity were significantly decreased in ADR treated group compared with the control group. Conversely, LVEDP and MyoCa2+ were significantly increased in ADR treated rabbits. CONCLUSION: Heart function can be decreased by regular-dose of ADR in injection. Calcium overload in cardiomyocyte and decrease of SR Ca2+ -ATPase activity is important physiopathologic mechanism in ADR-induced impairment of heart.

Primary abdominal lymphonodular cryptococcosis in children: 2 case reports and a literature review.

BACKGROUND: Cryptococcus neoformans is an important opportunistic fungal pathogen that is acquired via the respiratory tract. It causes several clinical syndromes and most commonly presents as meningitis. The establishment of C neoformans infections in immunocompetent individuals could be owing to increased virulence, dose of the organism, or genetically determined differences in the ability to generate a protective immune response against the organism. OBJECTIVES: The purpose of this study is to report on 2 case studies and a literature review and to discuss the diagnosis and management of primary abdominal lymphonodular cryptococcosis. METHODS: We conducted 2 case studies and a literature review. RESULTS: Two cases of primary abdominal lymphonodular cryptococcosis in childhood were reported herein. The patients suffered from C neoformans without immunoglobulin or lymphocyte abnormalities. The cause of hospitalization of the 2 cases was mainly the persisting fever with or without abdominal pain. Imaging findings indicated dramatic lymphadenopathy and light hepatosplenomegaly. Excision biopsy of the abnormal lymph node demonstrated reactive lymphoid hyperplasia and the presence of C neoformans. The results of nested polymerase chain reaction confirmed the diagnosis of C neoformans. CONCLUSION: This is the first report on C neoformans in the primary abdominal lymph node in children. This report suggests that C neoformans infection should be considered in the differential diagnosis of fever and marked lymphadenopathy, and empirical administration of antifungal agent may be necessary. C neoformans antibody test, polymerase chain reaction assay, fine-needle aspiration biopsy, or surgical excision biopsy is needed in early diagnosis.

[Correlation between infection of different glycoprotein B genotypes of human cytomegalovirus and human chronic periodontitis].

OBJECTIVE: To investigate the correlation between infection of different human cytomegalovirus (HCMV) glycoprotein B (gB) genotypes and human chronic periodontitis. METHODS: A nested-polymerase chain reaction (nPCR) was employed to detect HCMV gB gene in the subgingival plaque samples from 65 chronic periodontitis patients and in the gingival crevicular fluid samples from 24 periodontally healthy control. The amplification fragments of gB gene were further genotyped by restriction fragment length polymorphism (RFLP). The correlation among infection with the different HCMV genotypes and the severity of periodontal lesion were evaluated. RESULTS: In terms of teeth examined, the prevalence of HCMV (59.23%, 154/260) in the chronic periodontitis lesions was significantly higher than that of HCMV (32.29%, 31/96) in the periodontally healthy control (P < 0.01). Of the HCMV DNA positive samples from the chronic periodontitis lesions, 11.7% (18/154) was genotyped as gB I, 80.5% (124/154) as gB II, and 7.8% (12/154) as gB I and gB II co-infection, and of the HCMV DNA positive samples from the periodontal healthy control, 45.2% (14/31) was genotyped as gB I, 38.7% (12/31) as gB II, and 16.1% (5/31) as gB I and gB II co-infection. The gB II genotype was more dominant among the chronic periodontitis lesions compared with that among the periodontally healthy control (P < 0.01). In chronic periodontitis, no statistical significance could be found between infection of different HCMV gB genotypes and the different clinical parameters of CAL, PD and GI (P > 0.05). CONCLUSIONS: Subgingival infection with HCMV is closely associated with chronic periodontitis. Infection of HCMV may not correlate directly with severity of periodontitis. However, gB II may be the dominant genotype of HCMV, which is associated with the chronic periodontitis.

Cytomegalovirus gB genotype and clinical features in Chinese infants with congenital infections.

OBJECTIVE: To investigate cytomegalovirus (CMV) glycoprotein B (gB) genotypes and clinical features in Chinese infants with congenital infections. METHODS: Urine samples were obtained from 79 infants with human CMV infection confirmed by quantitative fluorescence polymerase chain reaction (PCR). A fragment of the gB gene was amplified by nested PCR. CMV gB genotyping was carried out by restriction fragment length polymorphism, and 24 samples of the amplified DNA fragments were verified by DNA sequencing. RESULTS: The levels of CMV DNA in symptomatic and asymptomatic infants were 2.95 x 10(5) and 4.5 x 10(3) copies/ml, respectively, with a significant difference (p < 0.001). In all these cases, the most prevalent genotype was gB1 (50.63%), followed by gB3 (21.52%), gB2 (17.72%), and coinfection (10.13%); gB4 was not found. Moreover, gB1 was more prevalent in infants with liver damage (22/32) than in other symptomatic infants without liver damage (8/22, p = 0.019) or asymptomatic infants (10/25, p = 0.030). The homology of CMV gB in the 24 strains amplified as compared with the sequences of prototype strains in GenBank ranged from 97.06 to 99.64%. CONCLUSIONS: The restriction fragment length polymorphism analysis of CMV gB genotypes was definite and reliable. The gB1 genotype is the most prevalent in Chinese infants with congenital CMV disease, especially in those with liver damage, followed by genotypes gB3, gB2, and gB4.

[Early arterial atherosclerosis and level of plasma homocysteine in simply obese children].

OBJECTIVE: To understand whether hyperhomocysteinemia and early arterial atherosclerosis exist in simply obese children. METHODS: Totally 68 simply obese children (age 6-14 years, mean 10.8 +/- 2.3 years) were enrolled in this study, 50 were male and 18 were female. Body mass index (BMI) of the obese children was equal to or more than 22. The height of the children was (145 +/- 22) cm. Meanwhile, 26 normal children (age 6 - 14 years, mean 10.9 +/- 2.0 years) were selected as control group, 17 of these children were male and 9 were female. Their height was (148.5 +/- 5.8) cm. There were no significant differences in height and age between the obese and the control children. The carotid intimal-medial thickness (IMT), brachial artery flow-mediated vasodilation were examined by Doppler Flow/Dimension System and the liver was examined by B-mode ultrasound imager. Plasma homocysteine was determined by the automated chemiluminescent enzyme immunoassays. Serum lipid concentration was determined by biochemical analytic method. Blood pressure of the right upper limbs was measured. A detailed medical and family history was systematically recorded. RESULTS: BMI was (27.8 +/- 4.5) in the obese children and (16.2 +/- 2.5) in the controls. There was significant difference between two groups (P < 0.01). The obese children had significantly increased values than the controls for the carotid intimal-medial thickness (P < 0.01). Right carotid IMT, right inner-carotid IMT, left carotid IMT and left inner-carotid IMT were respectively (0.54 +/- 0.13) mm, (0.69 +/- 0.14) mm, (0.52 +/- 0.12) mm and (0.67 +/- 0.14) mm in obese children and were respectively (0.45 +/- 0.04) mm, (0.46 +/- 0.04) mm, (0.45 +/- 0.05) mm and (0.46 +/- 0.03) mm in control groups. Conversely, the flow-mediated brachial artery dilation of the obese children was significantly lower than that of the controls [(11.0 +/- 4.3)% vs. (17.5 +/- 4.9)%, P < 0.01]. The obese children had higher level of plasma homocysteine than the controls [(7.9 +/- 2.7) micromol/L vs. (5.6 +/- 2.1) micromol/L, P < 0.01]. Total cholesterol (TC) in the obese children dramatically increased, so did triglyceride concentration (TG), LDL-cholesterol (LDL-ch) and apolipoprotein-B (apo-B). Of the obese children, had fatty liver or the tendency to fatty liver. Six cases of the 68 obese children (8%) had hypertension. Of the 68 obese children, 57 (84%) had the history of consuming excessive food or taking less exercise. Forty-four percent of the obese children (30/68) came from the obese families in which at least one of the parents or grandparents was obese. Twenty-nine percent (20/68) and 22% (15/68) of the obese children respectively came from the families in which at least one of the parents or grandparents suffered from hypertension or coronary heart disease. CONCLUSION: Early arterial atherosclerotic changes existed in simply obese children. Hyperhomocysteinemia may be an important factor of the obesity-induced early arterial atherosclerosis during childhood.

[Effects of insulin-like growth factor II on regulating nitric oxide synthase gene expression in mouse osteoblast-like MC3T3-E1 cells].

OBJECTIVE: To study the effects of insulin-like growth factor II (IGF-II) on regulating the levels of nitric oxide (NO) and the mRNA transcriptions of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) in mouse osteoblast-like cells. METHODS: Mouse osteoblastic cell line MC3T3-E1 was selected as the effective cell of IGF-II. After the cells were treated with IGF-II at different concentrations for different intervals of time, MTT colorimetry was used for examining the cell proliferation. Nitrate reductase method was applied for detecting the NO concentrations in cell culture supernatants and RT-PCR employed for determining the levels of cellular iNOS and eNOS mRNAs. RESULTS: After the MC3T3-E1 cells were treated with IGF-II at the dosages of 1 microg/L for 72 h, 10 and 100 microg/L for 24, 48 and 72 h respectively, all the MTT values increased markedly (P < 0.05 or P < 0.01). After the cells were treated for 48 and 72 h at the dosage of 100 microg/L IGF-II respectively, the levels of NO in the supernatants of cell cultures and cellular iNOS mRNA decreased significantly (P < 0.01). However, the levels of eNOS mRNA in the cells treated with any of the IGF-II dosages for the different times were stable (P > 0.05). CONCLUSIONS: IGF-II at the dosages of 1 approximately 100 microg/L showed the effects on promoting proliferation, which as probably due to the maintenance of low NO levels. Inducible NOS gene expression at the level of transcription was down regulated in the MC3T3-E1 cell treated with higher dosage of IGF-II (100 microg/L) but eNOS mRNA was not, which might be one of the mechanisms for the maintenance of low NO levels.