Co-delivery of paclitaxel and doxorubicin using polypeptide-engineered nanogels for combination therapy of tumor.

Loading of chemotherapeutic agents into nanoparticles has been demonstrated to be an effective strategy for cancer therapy. However, simultaneous delivery of different functional drugs to tumor sites for chemotherapy still remains challenging. In this study, nanogels formed by an engineered coiled-coil polypeptide PC10A were designed and prepared as a carrier for co-delivery of paclitaxel (PTX) and doxorubicin (DOX) through ultrasonic treatment and electrostatic adsorption. The drug loading content and encapsulation efficiency of PTX and DOX in the PC10A/PTX/DOX nanogels were 5.98 wt%, 70 wt%, and 8.55 wt%, 83 wt%, respectively. Because the polypeptide PC10A was non-toxic and biodegradable, the PC10A/PTX/DOX nanogels exhibited good biocompatibility. Thein vitroandin vivoantitumor experiments showed that the PC10A/PTX/DOX nanogels possessed obviously synergistic therapy effect of tumors and lower side effects compared with free PTX/DOX. Therefore, the PC10A/PTX/DOX nanogels are promising to provide a new strategy for combination therapy of different functional drugs.

[Role of NADPH oxidase in oxidative stress injury of human dermal fibroblasts].

OBJECTIVE: To investigate the role of NADPH oxidase (Nox) in the oxidative stress injury of human dermal fibroblasts (HFbs). METHODS: An oxidative stress injury model was established in HFbs by exposure to H(2)O(2). Normal HFbs and HFbs exposed to H(2)O(2) with and without pretreatment with NADPH oxidase inhibitor were tested for cell viability using MTT assay, and the intracellular reactive oxygen species (ROS) were determined with a DCFH-DA fluorescent probe. Western blotting was used to measure the protein expressions of membrane-bound subunit gp91phox of NADPH oxidase in the cells. RESULT: H(2)O(2) time- and concentration-dependently induced oxidative stress injury in the fibroblasts, causing a reduction of the cell viability to 40% after a 24-h exposure at 700 µmol/L (P<0.05) and an increase of ROS by 2 folds after a 2-h exposure at 700 µmol/L (P<0.05). Compared with the cells with oxidative stress injury, the cells with NADPH oxidase inhibitor pretreatment showed a 20% higher cell viability (P<0.05) and normal ROS level (P<0.05) following H(2)O(2) exposure. Western blotting demonstrated increased expression of gp91phox in the cells exposed to increasing H(2)O(2) concentrations, but gp91phox expression remained normal in cells pretreated with NADPH oxidase inhibitor. CONCLUSION: H(2)O(2) can induce oxidative stress injury in the fibroblasts by affecting NADPH oxidase, especially its membrane-bound subunit gp91phox.

Effects of velvet antler polypeptide on sexual behavior and testosterone synthesis in aging male mice.

Twenty-four-month-old male C57BL/6 mice with low serum testosterone levels were used as a late-onset hypogonadism (LOH) animal model for examining the effects of velvet antler polypeptide (VAP) on sexual function and testosterone synthesis. These mice received VAP for 5 consecutive weeks by daily gavage at doses of 100, 200, or 300 mg kg-1 body weight per day (n = 10 mice per dose). Control animals (n = 10) received the same weight-based volume of vehicle. Sexual behavior and testosterone levels in serum and interstitial tissue of testis were measured after the last administration of VAP. Furthermore, to investigate the mechanisms of how VAP affects sexual behavior and testosterone synthesis in vivo, the expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and 3ß-hydroxysteroid dehydrogenase (3ß-HSD) in Leydig cells was also measured by immunofluorescence staining and quantitative real-time PCR. As a result, VAP produced a significant improvement in the sexual function of these aging male mice. Serum testosterone level and intratesticular testosterone (ITT) concentration also increased in the VAP-treated groups. The expression of StAR, P450scc, and 3ß-HSD was also found to be enhanced in the VAP-treated groups compared with the control group. Our results suggested that VAP was effective in improving sexual function in aging male mice. The effect of velvet antler on sexual function was due to the increased expression of several rate-limiting enzymes of testosterone synthesis (StAR, P450scc, and 3ß-HSD) and the following promotion of testosterone synthesis in vivo.

Primary atypical teratoid/rhabdoid tumor of central nervous system in children: a clinicopathological analysis and review of literature in China.

Atypical teratoid/rhabdoid tumor (AT/RT) is a very rare and highly malignant embryonal tumor in the central nervous system (CNS). Five patients (4 girls and 1 boy) with AT/RT were treated in our hospital. The clinical histories, symptoms, neuroimaging aspects, therapies, histological and immunohistochemical findings and follow-up information were reviewed. The patients ranged from 8 to 40 months with a mean age of 20.6 months. One tumor was located in the spinal cord, two in cerebellum and two in the pineal region. The imagings of the tumors resemble medulloblastomas. Pathological examinations showed that one patient had medulloblastoma differentiation, one had choroid plexus carcinoma differentiation, and one had mesenchymal components. Immunohistochemical staining showed that all of the tumors lost the nuclear expression of integrase interactor 1 (INI1), and were positive for Vimentin, S-100 protein and epithelial membrane antigen. One case with no recurrence after 24 months may have benefited from radical excision and postoperative radiotherapy. The other 4 patients died 8, 4, 1 and 1-month respectively after operation without radiotherapy. The diagnosis of AT/RT depends on full sampling, careful observation the morphological characteristics and INI1 examination, even when the tumor are presented in uncommon sites, such as the spinal cord and the pineal region.

Hemangioendothelioma of the right atrial appendage associated with pericardial effusion in an infant.

BACKGROUND: Cardiac hemangioma is a rare cause for pericardial effusion. We present a case of hemangioendothelioma of the right atrial appendage associated with pericardial effusion in an infant. METHODS: The patient was a 49-day-old infant transferred to our department because of the presence of pericardial effusion. Two-dimensional transthoracic echocardiography revealed moderate pericardial effusion and a 24 mm × 16 mm hypoechoic mass located on the right side of the right ventricular outflow tract and in front of the aorta. RESULTS: The infant underwent an exploratory median sternotomy. In the pericardial cavity, 120 mL transudate was observed. A 15 mm × 15 mm encapsulated mass of soft tissue was located in the pericardial cavity and involved the right atrial appendage. The tumor with right atrial appendage was completely removed. Pathological examination revealed wide sessile implant basis of the tumor into the the myocardium of the right atrial appendage, with no affection to the endocardium. Hemangioendothelioma was confirmed histopathologically. Echocardiographic examination 2 years after operation revealed that the infant was free from tumor recurrence. CONCLUSIONS: Pericardial effusion may be caused by hemangioma of the right atrial appendage. The diagnosis of cardiac hemangioma is based on imaging examination and histopathological studies.

Follicular bronchiolitis in a child.

BACKGROUND: Follicular bronchiolitis (FB) is an uncommon but important pulmonary manifestation in children. METHODS: In this report, we present the clinical presentations and histopathological data of an 8-year-old boy with FB. RESULTS: The patient had a history of recurrent cough and dyspnea for 5 years with progressive worsening of symptoms. An initial pulmonary function test showed an obstructive ventilatory defect. Chest X-ray demonstrated miliary nodules. High-resolution computed tomography showed reticulonodular opacification and central consolidation. Histopathological examination revealed that lymphoid follicles with reactive germinal centers distributed along the bronchioles. The boy responded favorably to corticosteroid therapy and recovered well. CONCLUSIONS: Diagnosis of FB should be considered when a child presents with chronic bronchial obstruction. Open lung biopsy is necessary for confirmation of the diagnosis.

A retrospective study of the preoperative treatment of advanced Wilms tumor in children with chemotherapy versus transcatheter arterial chemoembolization alone or combined with short-term systemic chemotherapy.

PURPOSE: To evaluate the therapeutic effect of preoperative transcatheter arterial chemoembolization (TACE) combined with short-term systematic chemotherapy in the treatment of advanced Wilms tumor. MATERIALS AND METHODS: This was a retrospective study on 66 patients with unilateral advanced Wilms tumor, age 5 months to 11 years (median, 2.9 years; 30 boys and 36 girls), treated at our institution between 1995 and 2007. Characteristics of the patient population were maximal tumor diameter > 10 cm, or involvement of periaortic lymph nodes, or inferior vena cava invasion, or distal metastasis, or tumor with anaplastic histology. Patients were divided into three groups. Twenty patients were treated with conventional preoperative chemotherapy (PC group) using vindesine, actinomycin D, and pirarubicin for 4 weeks; 21 patients were treated in the TACE group with preoperative renal arterial chemoembolization using Lipiodol-pirarubicin-vindesine emulsion; and 25 patients were treated with preoperative chemoembolization combined with short-term systematic chemotherapy (T+S) for 2 weeks. RESULTS: No drug-induced cardiotoxicity, nephrotoxicity, or hepatic dysfunction was observed. Complete surgical removal of the tumor was achieved in 12 (65.0%), 17 (80.9%), and 22 (88.0%) patients in the PC, TACE, and T+S groups, respectively (T+S group vs PC group, P = .030). The 2-year relapse-free survival rates were 65.0%, 80.9%, and 100.0% in the PC, TACE, and T+S groups, respectively (T+S vs PC, P = .001). CONCLUSIONS: From our experience, preoperative chemoembolization combined with short-term systematic chemotherapy is able to achieve higher rates of complete tumor resection and relapse-free survival in the treatment of advanced Wilms tumor.

Predictive factors and unfavourable prognostic factors of interstitial lung disease in patients with polymyositis or dermatomyositis: a retrospective study.

BACKGROUND: Interstitial lung disease (ILD) is a serious lung complication in polymyositis (PM) and dermatomyositis (DM) which affects prognosis and requires a more aggressive approach in therapy. This study investigated the prevalence, characteristics, predictive factors and unfavourable prognostic factors of ILD in newly diagnosed PM, DM and amyopathic DM (ADM). METHODS: From January 2000 to December 2008, the medical records of 197 consecutive PM and DM patients at the Second Affiliated Hospital of Sun Yat-Sen University were reviewed excluding overlapping, juvenile, and malignancy-associated cases. The patients were assigned to an ILD (69 patients) and a non-ILD group (128 patients). The clinical features, laboratory findings, and prognosis were compared. RESULTS: The multivariate analysis indicated that older age at onset (OR 1.033, 95%CI 1.009 - 1.058, P = 0.007), fever (OR 4.109, 95%CI 1.926 - 8.767, P < 0.001) and arthritis/arthralgia (OR 2.274, 95%CI 1.101 - 4.695, P = 0.026) were the independent predictive factors for developing ILD in PM/DM after excluding anti-Jo-1. Regarding anti-Jo-1, fever (OR 4.912, 95%CI 2.121 - 11.376, P < 0.001) was associated with ILD. Poor survival in ILD patients was associated with ILD clinical subset (RR 0.122, 95%CI 0.049 - 0.399, P < 0.001), ADM/DM/PM-ILD (RR 0.140, 95%CI 0.031 - 0.476, P = 0.002), cardiac involvement (RR 4.654, 95%CI 1.391 - 15.577, P = 0.013) and serum albumin level (RR 0.910, 95%CI 0.831 - 0.997, P = 0.042). CONCLUSIONS: Patients who presented with fever tended to have a higher frequency of PM/DM-associated ILD. A Hamman-Rich-like presentation, ADM-ILD, cardiac involvement and hypoalbuminemia were poor prognostic factors in ILD-PM/DM.

[Establishment of animal model with B lineage acute leukemia in nude mice for evaluation of new therapeutic agents].

OBJECTIVE: To establish an acute leukemia animal model for testing new therapeutic agents in vivo. METHODS: Nude mice were intraperitoneally injected with 2 mg cyclophosphamide, 24 h later 5 x 10(6) acute B-cell leukemia Nalm-6 cells was inoculated via the tail vein, then monitored daily. When animals were paralyzed or dying, the organs including the liver, spleen, lung, heart, kidney, brain, bone marrow, pancreas, testes were removed and fixed with formalin, examined by routine histopathology. RESULTS: After Nalm-6 cells were inoculated the mean survival of mice were( 19.4+/-0.55)d (n=6). The paralysis of mice was followed by weight loss, bent spines, hogback, cachexia and death. Histopathological examination showed that the tumor cells infiltrated liver, spleen, kidney, lung, meninges, interior cerebrum, the liver and kidney were the most affected organs. CONCLUSION: B lineage acute leukemia animal model has been successfully established in the nude mice, which is suitable for testing new therapeutic agents.

Childhood pancreatoblastoma: clinical features and immunohistochemistry analysis.

Pancreatoblastoma (PB) is an extremely rare pancreatic tumor that is most commonly encountered in infants and young children. In this study, three cases of childhood pancreatoblastoma are reported to emphasize the clinical features, laboratory findings, diagnosis, and management of this rare disease. They were two boys and one girl, aged 3 days, 4.6, and 4.7 years, respectively. The main causes of hospitalization were abdominal pain and diarrhea. Elevated serum alpha-foetoprotein levels were noted in all cases. Imaging findings indicated a well-defined heterogeneous large mass in the pancreas or mesentery. The diagnosis was confirmed by histopathology. Immunohistochemical staining showed cytokeratin AE1/AE3 and carcinoembryonic antigen positive in all samples, epithelial membrane antigen, S-100 and alpha-foetoprotein positive in two, neurone-specific enolase, chromogranin A, synaptophysin, and 5-hydroxytryptamine positive in one. Surgery alone was performed for two cases, and the other case with a huge mass was administrated combination therapy (chemotherapy, tumorectomy, and radiotherapy), with a good outcome in the follow-up. These data suggest the diagnosis of PB depends mainly on the pathological findings. The PB should be included in the differential diagnosis of a mass in the pancreas or mesentery, especially with elevated AFP and a well-defined heterogeneous imaging finding.

[Effect of preoperative transcatheter arterial chemo-embolization on activity of cell proliferation in Wilms; tumor].

OBJECTIVE: To investigate the effect of preoperative transcatherter arterial chemo-embolization (TACE) on the cell proliferation in Wilms; tumor. METHODS: Forty-one cases of Wilms; tumor diagnosed by histopathology were divided into two groups: in TACE group, 23 patients received TACE first and were operated 2 weeks later; in control group, 18 patients were operated alone. A comparative analysis of the pathological finding was made in two groups, and the expression of PCNA and VEGF in tumor tissue was detected by immunohistochemistry. RESULT: The degeneration of tumor tissue such as tumor cell necrotic, broken, disappearance occurred in 17 cases of TACE group and in 4 cases of control group, respectively (P <0.01). The expression of PCNA in TACE group and in control group was 1/23 (4.3 %) and 9/18(50.0 %), respectively (P <0.01). VEGF was expressed in 7/23 (30.4 %) of TACE group and 9/18 (50.0 %) of control group (P=0.283). CONCLUSION: TACE can significantly inhibit proliferation and enhance degeneration of Wilms; tumor cells.

Viral pathogens of acute lower respiratory tract infection in China.

OBJECTIVES: To document the viral etiology of acute lower respiratory tract infection (ALRIs) in Chinese children. SETTING: Children Hospital, Zhejiang University, China. STUDY DESIGN: Cross-sectional. PARTICIPANTS: 34885 children with ALRI between January 2001 to December 2006. METHODS: Nasopharyngeal aspirates were collected from all subjects. Respiratory syncytial virus (RSV), adenovirus (ADV), type 1 to 3 parainfluenza viruses (PIV), and type A and B influenza virus (Flu) were detected by direct immunofluorescence. RESULTS: Viruses were identified in 32.3% cases, including RSV (23.6%), PIV 3 (4.3%), Flu A (2.0%), ADV (1.7%), PIV I (0.6%), Flu B (0.2%) and PIV 2 (0.1%). RSV and PIV 3 predominated in younger children while Flu A and Flu B predominated in older children (P<0.001, respectively). PIV 1 was more prevalent in children aged 1 to 3 years. The peak frequency of RSV, PIV 3 and Flu A were in early spring, June to August, and August and September, respectively. Flu B had a peak in the winter and spring. Adenovirus infections occurred in all seasons with a relatively constant frequency. CONCLUSIONS: Viruses are an important cause of ALRIs in Chinese children constituting 1/3 of total cases. RSV is the most common pathogen.

[The relationship between postoperative complication and pathological features of 324 patients with neuronal intestinal malformations].

OBJECTIVE: To investigate the relationship between the morphological features of different types of neuronal intestinal malformations (NIM) and their postoperative complications. METHODS: The data of morphological and clinical features of 324 cases with NIM were analyzed retrospectively. RESULTS: In all 324 patients, 210 cases were Hirschsprung's disease (HD), 38 intestinal neuronal dysplasia (IND), 45 mixed HD/IND, 8 hypoganglionosis, 22 combined HD/hypoganglionosis and 1 immaturity of ganglion cells. The percentages of normal neuron in bowel of different NIM were 88.1%, 24.4%, 18.4%, 4/8, 27.7% and 0/1 in HD, HD/IND, IND, hypoganglionosis, HD/hypoganglionosis and immaturity of ganglion cells respectively. There were totally 46 cases complicated with recurrent postoperative enterocolitis (EC). Incidence of recurrent postoperative EC in HD patients was 6.7% while in IND/HD and IND patients was 35.6% and 28.9%, respectively. Incidences of EC in cases with the residual IND margins and with the normal margins were 38.2% and 8.7%, respectively. Incidence of EC in cases with transanal endorectal pull-through procedure and with transabdominal procedure was 18.0% and 8.3%, respectively. Nine cases underwent another procedure because of severe persistent constipation or EC after operation, including 4 cases HD/IND, 1 case IND, 3 cases HD and 1 case HD/hypoganglionosis. CONCLUSIONS: Neuron distribution is inconsistent with pathology of NIM. Postoperative EC are rare in the patients only with isolated HD. Furthermore, margins with residual IND and transanal endorectal pull-through procedure are risk factors to recurrent EC. However, the extension of excision about IND is uncertain and need further study.

[Treatment of advanced Wilms' tumor].

OBJECTIVE: To improve prognosis of the patients with advanced Wilms' tumor, the authors compared different therapeutic strategies including preoperative transcatheter arterial chemoembolization (TACE), conventional preoperative chemotherapy and initial surgery. METHODS: Sixty-two patients aged from 5 months to 10 years (mean 3.2 years) were identified from medical records to have histologically confirmed advanced Wilms' tumor during the period from January 1993 to December 2002. The criteria for choice were huge tumor size with a volume more than 550 ml or the mass extending beyond the midline, involvement of vital structures, inferior vena cava invasion, distal metastasis or bilateral Wilms' tumor judged by imaging examination. All cases were divided into 3 groups according to the treatment received: 31 cases in group TACE received preoperative transcatheter arterial chemoembolization with Lipiodol-Epirubicin (EPI)-Vincristine emulsion. One week after TACE, systemic chemotherapy with Actinomycin D (ACTD) was administered and tumor resected at two weeks after TACE. 20 cases in group PC received conventional preoperative chemotherapy with VCR, ACTD plus EPI for 4-5 weeks, and 11 cases in group IS underwent initial surgery. Postoperative treatment for all patients was based on the postoperative staging and tumor histology. RESULTS: In the patients treated with TACE, no drug-induced complications such as cardiotoxicity, nephrotoxicity, hepatic dysfunction or bone marrow suppression were observed except for mild fever due to tumor necrosis. The percentages of tumor size shrinkage were 32.4% and 20.3% in group TACE and group PC, respectively (P < 0.05). Complete surgical removal of the tumor was achieved in 27 patients (87.1%) in group TACE, significantly higher in comparison with 14 in group PC (70.0%, P < 0.05) and 2 in group IS (18.2%, P < 0.01). Event-free survival (EFS) at 2 years was 87.1% (27/ 31), 60.0% (12/20) and 18.2% (2/11), respectivrely. EFS at 4 years was 84.6% (11/13), 56.3% (9/16 ) and 18.2% (2/11) in groups TACE, PC and IS, respectively. CONCLUSION: The present study has shown that both preoperative TACE and conventional preoperative chemotherapy can be applied to the patients with advanced Wilms' tumor who are not candidates for immediately surgical resection. The survival is significantly increased in the patients undergoing preoperativeTACE when compared with conventional preoperative chemotherapy and initial surgery.

[Effect of VEGF gene transfer on the bleomycin-induced pulmonary hypertension in immature rabbits].

OBJECTIVE: To investigate the effect of vascular endothelial growth factor (VEGF) gene transfer on the bleomycin(BLM)-induced pulmonary hypertension in immature rabbits. METHODS: Immature rabbits were divided into 4 groups; control, BLM, liposome and trans-gene groups. The systolic, diastolic and mean pulmonary artery pressure (PASP, PADP, MPAP) were measured by micro-catheter, the pathological changes and the expression of VEGFmRNA and eNOSmRNA of endothelial cells in pulmonary arteries were evaluated by HE stain and in situ hybridization. RESULT: (1) The PAP of BLM and liposome groups was higher than that of control and trans-gene groups. The PASP was 16.5+/-2.9, 25.2+/-7.0, 24.4+/-6.0 and 18.3+/-2.7 mmHg; the PADP was 8.8+/-4.2, 13.1+/-3.8, 13.7+/-4.6 and 10.2+/-2.6 mmHg; the MPAP was 12.1+/-4.0, 18.4+/-4.7, 18.4+/-5.1 and 14.1+/-2.5 mmHg in control, BLM, liposome and trans-gene groups respectively. (2) The thickness of wall increased and the cavity became narrow, and the thickness index (TI) and area index (AI) increased in middle and small pulmonary arteries of BLM and liposome groups. The TI was 0.52+/-0.16, 0.65+/-0.16, 0.63+/-0.11 and 0.55+/-0.13; and the AI was 0.74+/-0.17, 0.84+/-0.14, 0.85+/-0.08 and 0.79+/-0.12 in control, BLM, liposome and trans-gene groups,respectively. (3) The level of VEGFmRNA and eNOSmRNA expression in pulmonary arterial endothelial cells decreased in BLM and liposome groups. The level of VEGFmRNA and eNOSmRNA expression in trans-gene group was higher than that in BLM and liposome groups, but lower than that in control group. VEGFmRNA was 0.83+/-0.09, 0.45+/-0.11, 0.45+/-0.13 and 0.65+/-0.18; eNOSmRNA was 0.79+/-0.12, 0.45+/-0.12, 0.50+/-0.14 and 0.56+/-0.08 in control, BLM, liposome and trans-gene groups, respectively. CONCLUSION: VEGF gene transfer in immature rabbits with BLM-induced pulmonary hypertension could attenuate the increasing of PAP and wall thickness in middle and small pulmonary arteries, and increase the level of VEGFmRNA and eNOSmRNA expression in pulmonary arterial endothelial cells.

[Viral etiology of pneumonia in children].

OBJECTIVE: To evaluate the viral pathogen of pneumonia in children. METHODS: A total of 13 642 cases of children pneumonia in 3 years were enrolled in this study. Antigens of viral pathogen in respiratory excretion, including respiratory syncytial virus (RSV), type 1, 2 and 3 parainfluenza virus, type A and B influenza virus, and adenovirus were detected by direct immunofluorescence method. RESULTS: Viral pneumonia accounted for 34.3% of all cases, including 25.8% cases of RSV, 4.7% of parainfluenza virus, 2.4% of type A influenza virus, 0.2% of type B influenza virus and 1.3% of adenovirus. Coinfection was found in 20 cases, in which 17 cases (85%) were infected with RSV and another virus. Positive rates of RSV in children < or = 1 year, 1 to 3 years, and >3 years were 33.1%, 19.7% and 5.1% with a significant difference (chi(2)(trend)=763.4, P < 0.001). The positive rate of adenovirus in children < or =1 year (0.7%) was significantly lower than that in children aged 1 to 3 years and in children >3 years (2.3% and 2.5%) (all P<0.01). The positive rate of type A influenza virus in children aged 1 to 3 years was higher than that in children < or =1 year (chi(2)=18.2, P<0.01). Type 1 parainfluenza virus was found in 1.2% children aged 1 to 3 years with most prevalence (P<0.05). Infection rates of type 3 parainfluenza in children < or =1 year, 1 to 3 years, and >3 years were 4.7%, 3.2% and 1.4% respectively with a significant difference (chi(2)(trend)=52.4, P<0.01). Although there were some differences of infection rate of RSV in different years, it tended to increase from November to next April with a highest rate of 62.8%. Type 3 parainfluenza virus and Type A influenza virus were almost sporadic while type A influenza virus was epidemic in August 2003 with an infection rate of 15.7%. CONCLUSION: The highest infection rate of viral pathogen of pneumonia in children is RSV and the follows are parainfluenza, influenza and adenovirus in turn.

[Pathophysiology of bleomycin-induced pulmonary hypertension in immature rabbits].

OBJECTIVE: To investigate the evolution of pulmonary hypertension induced by intratracheal bleomycin (BLM) in immature rabbits. METHODS: Immature rabbits were divided into control and BLM groups. Two and four weeks after intratracheal normal saline or BLM, the systolic, diastolic and mean pulmonary artery pressure (PASP, PADP, MPAP) were measured by micro-catheter, the pathological changes and the expression of VEGFmRNA and eNOSmRNA of endothelial cells in pulmonary arteries were evaluated by HE and in situ hybridization. RESULTS: Pulmonary artery pressure was elevated 2 weeks and 4 weeks after intratracheal BLM. Two weeks after treatment PASP was (16.5 +/- 2.9 compared with 25.2 +/- 7.0) mmHg, PADP (8.8 +/- 4.2 compared with 13.1 +/- 3.8) mmHg, MPAP (12.1 +/-4.0 compared with 18.4 +/-4.7) mmHg in control and BLM groups, respectively; meanwhile 4 weeks after treatment, PASP was (16.7 +/-2.3 compared with 23.8 +/-7.1) mmHg, PADP (7.3 +/-1.5 compared with 13.8 +/-6.6) mmHg, MPAP (11.3 +/- 1.9 compared with 17.6 +/- 6.3) mmHg in control and BLM groups, respectively. The thickness of arterial wall increased and the cavity became narrow, and the thickness index (TI) and area index (AI) increased in middle and small pulmonary arteries 2 weeks and 4 weeks after intratracheal BLM. Two weeks after treatment TI was 0.52 +/- 0.16 compared with 0.65 +/- 0.16, AI 0.74+/- 0.17 compared with 0.84 +/- 0.14 in control and BLM groups, respectively; meanwhile 4 weeks after treatment TI was 0.52 +/- 0.11 compared with 0.64 +/- 0.15, AI 0.71 +/- 0.15 compared with 0.85 +/- 0.10 in control and BLM groups. The levels of VEGFmRNA and eNOSmRNA expression in pulmonary arterial endothelial cells decreased 2 weeks and 4 weeks after intratracheal BLM. Two weeks after treatment VEGFmRNA was 0.83 +/- 0.09 compared with 0.45 +/- 0.11, eNOSmRNA 0.79 +/- 0.12 compared with 0.45 +/- 0.12 in control and BLM groups, respectively; meanwhile 4 weeks after VEGFmRNA was 0.81 +/- 0.19 compared with 0.46 +/- 0.15, eNOSmRNA 0.89 +/- 0.14 compared with 0.44 +/- 0.12 in control and BLM groups, respectively. CONCLUSION: Intratracheal bleomycin may induce the pathological changes of pulmonary arteries and decrease the expression of VEGFmRNA and eNOSmRNA in immature rabbits, which results in pulmonary hypertension.