[Outcomes and care practices of extremely preterm infants at 22-25 weeks' gestation age from the Chinese Neonatal Network]

Objective: To describe the current status and trends in the outcomes and care practices of extremely preterm infants at 22-25 weeks' gestation age from the Chinese Neonatal Network (CHNN) from 2019 to 2021. Methods: This cross-sectional study used data from the CHNN cohort of very preterm infants. All 963 extremely preterm infants with gestational age between 22-25 weeks who were admitted to neonatal intensive care units (NICU) of the CHNN from 2019 to 2021 were included. Infants admitted after 24 hours of life or transferred to non-CHNN hospitals were excluded. Perinatal care practices, survival rates, incidences of major morbidities, and NICU treatments were described according to different gestational age groups and admission years. Comparison among gestational age groups was conducted using χ2 and Kruskal-Wallis tests. Trends by year were evaluated by Cochran-Armitage and Jonckheere-Terpstra tests for trend. Results: Of the 963 extremely preterm infants enrolled, 588 extremely preterm infants (61.1%) were male. The gestational age was 25.0 (24.4, 25.6) weeks, with 29 extremely preterm infants (3.0%), 88 extremely preterm infants (9.1%), 264 extremely preterm infants (27.4%), and 582 extremely preterm infants (60.4%) at 22, 23, 24, and 25 weeks of gestation age, respectively. The birth weight was 770 (680, 840) g. From 2019 to 2021, the number of extremely preterm infants increased each year (285, 312, and 366 extremely preterm infants, respectively). Antenatal steroids and magnesium sulfate were administered to 67.7% (615/908) and 51.1% (453/886) mothers of extremely preterm infants. In the delivery room, 20.8% (200/963) and 69.5% (669/963) extremely preterm infants received noninvasive positive end-expiratory pressure support and endotracheal intubation. Delayed cord clamping and cord milking were performed in 19.0% (149/784) and 30.4% (241/794) extremely preterm infants. From 2019 to 2021, there were significant increases in the usage of antenatal steroids, antenatal magnesium sulfate, and delivery room noninvasive positive-end expiratory pressure support (all P<0.05). Overall, 349 extremely preterm infants (36.2%) did not receive complete care, 392 extremely preterm infants (40.7%) received complete care and survived to discharge, and 222 extremely preterm infants (23.1%) received complete care but died in hospital. The survival rates for extremely preterm infants at 22, 23, 24 and 25 weeks of gestation age were 10.3% (3/29), 23.9% (21/88), 33.0% (87/264) and 48.3% (281/582), respectively. From 2019 to 2021, there were no statistically significant trends in complete care, survival, and mortality rates (all P>0.05). Only 11.5% (45/392) extremely preterm infants survived without major morbidities. Moderate to severe bronchopulmonary dysplasia (67.3% (264/392)) and severe retinopathy of prematurity (61.5% (241/392)) were the most common morbidities among survivors. The incidences of severe intraventricular hemorrhage or periventricular leukomalacia, necrotizing enterocolitis, and sepsis were 15.3% (60/392), 5.9% (23/392) and 19.1% (75/392), respectively. Overall, 83.7% (328/392) survivors received invasive ventilation during hospitalization, with a duration of 22 (10, 42) days. The hospital stay for survivors was 97 (86, 116) days. Conclusions: With the increasing number of extremely preterm infants at 22-25 weeks' gestation admitted to CHNN NICU, the survival rate remained low, especially the rate of survival without major morbidities. Further quality improvement initiatives are needed to facilitate the implementation of evidence-based care practices.

[Management and prognosis of extremely preterm infants with gestational age ≤25+6 weeks]

Objective: To investigate the outcomes including major complications and prognosis of extremely preterm infants with gestational age ≤25⁺⁶ weeks. Methods: The cross-sectional study enrolled 233 extremely preterm infants with gestational age ≤25⁺⁶ weeks who were admitted to the Department of Neonatology of Shenzhen Maternity and Child Healthcare Hospital from January 2015 to December 2021. The clinical data including perinatal factors, treatments, complications, and prognosis were extracted and analyzed. These extremely preterm infants were also grouped according to gestational age and year of admission to further analyze their survival rate, major complications, causes of death, and long-term outcomes. The comparisons between the groups were performed with Chi-square test and Kruskal-Wallis. Results: Among these 233 extremely preterm infants, 134 (57.5%) were males and 99 (42.5%) females. The gestational age was (24.6±0.9) weeks, the birth weight was 710.0 (605.0,784.5) g, and the overall survival rate was 61.8% (144/233). Among the surviving extremely preterm infants, the earliest gestational age was 22⁺² weeks and the lowest birth weight was 390 g. There were 17.6% (41/233) of extremely preterm infants had treatment withdrawn and were discharged in line with the will of guardians. Among the rest 192 extremely preterm infants managed with aggressive treatments, 14 (7.3%) died in hospital and 34 (17.7%) had treatment withdrawn later due to severe complications. Of the 192 extremely preterm infants, 144 (75.0%) survived, and the survival rate increased year by year (χ²=26.28, P<0.001) while the mortality decreased year by year (χ²=14.09, P=0.027). Among the survivors, 20.8%(30/144) had no major complications, and the incidence of complications was also negatively related with the gestational age (χ²=7.24, P=0.044), and the length of invasive ventilation was negatively related to the gestational age (χ²=29.14, P<0.001). In the group of less than 23⁺⁶ weeks, all extremely preterm infants had one or more major complications. The follow-up were completed in 122 infants and revealed that delayed motor development, language retardation, and hearing and vision impairment accounted for 17.2% (21/122), 8.2% (10/122) and 17.2% (21/122), respectively. Conclusions: Extremely preterm infants with gestational age ≤25⁺⁶ weeks are difficult to treat, but the survival rate of infants undergoing aggressive treatments increases year by year. Although the prevalence of major complications is still high, most extremely preterm infants have acceptable prognosis during follow-up.

[Status of fungal sepsis among preterm infants in 25 neonatal intensive care units of tertiary hospitals in China]

Objective: To analyze the prevalence and the risk factors of fungal sepsis in 25 neonatal intensive care units (NICU) among preterm infants in China, and to provide a basis for preventive strategies of fungal sepsis. Methods: This was a second-analysis of the data from the "reduction of infection in neonatal intensive care units using the evidence-based practice for improving quality" study. The current status of fungal sepsis of the 24 731 preterm infants with the gestational age of <34⁺⁰ weeks, who were admitted to 25 participating NICU within 7 days of birth between May 2015 and April 2018 were retrospectively analyzed. These preterm infants were divided into the fungal sepsis group and the without fungal sepsis group according to whether they developed fungal sepsis to analyze the incidences and the microbiology of fungal sepsis. Chi-square test was used to compare the incidences of fungal sepsis in preterm infants with different gestational ages and birth weights and in different NICU. Multivariate Logistic regression analysis was used to study the outcomes of preterm infants with fungal sepsis, which were further compared with those of preterm infants without fungal sepsis. The 144 preterm infants in the fungal sepsis group were matched with 288 preterm infants in the non-fungal sepsis group by propensity score-matched method. Univariate and multivariate Logistic regression analysis were used to analyze the risk factors of fungal sepsis. Results: In all, 166 (0.7%) of the 24 731 preterm infants developed fungal sepsis, with the gestational age of (29.7±2.0) weeks and the birth weight of (1 300±293) g. The incidence of fungal sepsis increased with decreasing gestational age and birth weight (both P<0.001). The preterm infants with gestational age of <32 weeks accounted for 87.3% (145/166). The incidence of fungal sepsis was 1.0% (117/11 438) in very preterm infants and 2.0% (28/1 401) in extremely preterm infants, and was 1.3% (103/8 060) in very low birth weight infants and 1.7% (21/1 211) in extremely low birth weight infants, respectively. There was no fungal sepsis in 3 NICU, and the incidences in the other 22 NICU ranged from 0.7% (10/1 397) to 2.9% (21/724), with significant statistical difference (P<0.001). The pathogens were mainly Candida (150/166, 90.4%), including 59 cases of Candida albicans and 91 cases of non-Candida albicans, of which Candida parapsilosis was the most common (41 cases). Fungal sepsis was independently associated with increased risk of moderate to severe bronchopulmonary dysplasia (BPD) (adjusted OR 1.52, 95%CI 1.04-2.22, P=0.030) and severe retinopathy of prematurity (ROP) (adjusted OR 2.55, 95%CI 1.12-5.80, P=0.025). Previous broad spectrum antibiotics exposure (adjusted OR=2.50, 95%CI 1.50-4.17, P<0.001), prolonged use of central line (adjusted OR=1.05, 95%CI 1.03-1.08, P<0.001) and previous total parenteral nutrition (TPN) duration (adjusted OR=1.04, 95%CI 1.02-1.06, P<0.001) were all independently associated with increasing risk of fungal sepsis. Conclusions: Candida albicans and Candida parapsilosis are the main pathogens of fungal sepsis among preterm infants in Chinese NICU. Preterm infants with fungal sepsis are at increased risk of moderate to severe BPD and severe ROP. Previous broad spectrum antibiotics exposure, prolonged use of central line and prolonged duration of TPN will increase the risk of fungal sepsis. Ongoing initiatives are needed to reduce fungal sepsis based on these risk factors.

[Clinical report of hoding cricoarytenoid joint reduction with visual laryngoscope under intravenous anesthesia]

Objective: To investigate the reduction effect of hoding cricoarytenoid joint reduction with visual laryngoscope under intravenous anesthesia. Methods: The therapeutic effects of 40 patients with arytenoid dislocation(AD)treated by closed reduction in the single center from January 2020 to September 2021 were retrospectively analyzed, including 21 males and 19 females, median age 48 years. The etiology, symptoms, preoperative evaluation methods, reduction mode, reduction times, and the recovery of arytenoid cartilage movement and sound after reduction were evaluated and analyzed. Results: All patients had obvious hoarseness and breath sound before treatment. Under stroboscopic laryngoscope or electronic nasopharyngoscope, different degrees of vocal cord movement disorder and poor glottic closure can be seen. There were 28 cases of left dislocation, 9 cases of right dislocation and 3 cases of bilateral dislocation. The etiology of dislocation of cricoarytenoid joint: 25 cases (62.5%) of tracheal intubation under general anesthesia were the most common causes, was as follows by laryngeal trauma, gastroscopy, cough, vomiting and so on. Among them, 28 cases of reduction were initially diagnosed in our department, and 12 cases were diagnosed later after failure of reduction treatment. Of the 40 patients, 6 underwent reduction 24 hours after dislocation; 18 cases from 3 days to 1 month; 7 cases from 1 to 3 months; 6 cases were reset in 3~6 months; Over 6 months in 3 cases. After one reduction, 10 cases (10/40, 25%) recovered normal pronunciation, 14 cases (14/40, 35%) recovered normal pronunciation after two reduction, 10 cases (10/40, 25%) recovered normal pronunciation after three times, 2 cases (2/40, 5%) recovered normal pronunciation after four times, and 1 case (2.5%) recovered normal pronunciation after five times. Thin slice CT scan of larynx and cricoarytenoid joint reconstruction showed the types of AD: subluxation in 37 cases (92.5%) and total dislocation in 3 cases; 28 cases of left dislocation, 9 cases of right dislocation and 3 cases of bilateral dislocation; 29 cases (72.5%) had posterior dislocation and 11 cases (27.5%) had anterior dislocation. All patients were treated by intravenous anesthesia with arytenoid cartilage clamped by cricoarytenoid joint reduction forceps under visual laryngoscope. The curative effect was evaluated by stroboscopic laryngoscope and/or voice analysis at 1-2 weeks after operation. The vocal cord movement returned to normal and the pronunciation was good in 37 cases (92.5%). Conclusions: Hoding cricoarytenoid joint reduction with the vision laryngoscope under intravenous anesthesia is easy to operate and the reduction effect is more stable. It is a effective method for AD.

[Post-discharge growth of extremely premature infants within corrected age of 24 months]

Objective: To demonstrate the post-discharge catch-up growth of extremely premature infants (EPI) within 24 months of corrected age. Methods: This study retrospectively collected the anthropomorphic measurements of 311 EPI who visited Shenzhen Maternity and Child Healthcare Hospital from August 2013 to April 2020. These infants were stratified according to gestational age at birth (GA): 23-24⁺⁶weeks, 25-26⁺⁶weeks, 27-27⁺⁶weeks; and birth weight:<750 g, 750-999 g, ≥1 000 g. The anthropomorphic measurements, including weight, length, and head circumference for age, were recorded timely from discharge to 24 months of corrected age. And the growth curve stratified by GA and birth weight were fitted in both chronological age and corrected age, which were then compared with the World Health Organization Child Growth Standards for term infant (2006 version), to investigate the catch-up growth pattern of EPI. And appropriate catch-up was defined as the measurements reached the 25^th percentile of WHO growth curve. Results: In these 311 EPI, 184 were males and 127 females, with gestational age of 23-27⁺⁶ weeks and birth weight of 480-1 430 g. Regardless of the GA and birth weight, the growth curves fitted in corrected age failed to overlap with that in chronological age by 24 months of corrected age. The growth velocity of weight, length and head circumference in both corrected and chronological age were all positively correlated with GA and birth weight: the 27-27⁺⁶weeks group showed a preferable growth pattern than the 25-26⁺⁶weeks group, and the curve of the 23-24⁺⁶weeks group was most unfavorable; and the same pattern was observed between the subgroups of different birth weight. Furthermore, the GA had more significant impact on the catch-up growth pattern than birth weight did. When assessed with corrected age curve, the weight and length of both male and female EPIs achieved appropriate catch-up by 24 months, as well as the head circumference of girls; whereas, boys' head circumference reached appropriate catch-up at the corrected age of 9 months, but fell behind the 25^th percentile after that. However, when assessed with chronological age curve, both boys and girls failed to achieve appropriate catch-up in weight, length and head circumference by age 24 months. And no matter in corrected or chronological age, all physical measurements of girls were lower than those of boys. Conclusions: The rapid catch-up growth of EPI happens within 6 months of corrected age. The lower the birth weight and gestational age, the lower the physical measurements at each corresponding month of age, and the longer it takes to achieve appropriate catch-up. Gestational age has a greater impact on the longitudinal catch-up growth than birth weight does. And girls generally grow slower than boys in either correct or actual age. Before 24 months of corrected age, the growth should be assessed with corrected age rather than chronological age.

[Risk factors and prognosis of bronchopulmonary dysplasia associated pulmonary hypertension in preterm infants]

Objective: To analyze clinical features, prognosis and risk factors of bronchopulmonary dysplasia (BPD) associated pulmonary hypertension (PH). Methods: Clinical data of 338 infants with BPD were collected from the neonatal intensive care unit (NICU) in Shenzhen Maternity and Child Healthcare Hospital, Southern Medical University between January 2016 and December 2018. These infants were divided into PH group and non-PH group. The clinical features and prognosis were compared between these two groups by Chi-square test or nonparametric test. Risk factors for BPD-PH were analyzed with binary logistic regression model. Results: Among the 338 BPD infants, 314 had no PH (92.9%) and 24 had PH (7.1%), with an average gestational age of (27.1±1.8) weeks, and 206 were males and 132 females.PH infants had younger gestational age ((26.4±2.1) vs. (27.2±1.7) weeks, t=2.201, P=0.028) and lower birth weight ((798±255) vs. (1 003±240) g, t=4.030, P<0.01), compared to non-PH infants. Besides, duration of mechanical ventilation and non-invasive positive pressure ventilation were higher in PH group than that in non-PH group (14.3 (2.1, 43.7) vs. 0.5 (0, 4.7) d, Z=-4.553, P<0.01; 30.0 (22.5, 64.2) vs. 15.0 (7.0, 26.0) d, Z=-4.838, P<0.01). The proportions of maternal hypertension, small for gestational age (SGA), late onset sepsis, ventilator associated pneumonia, hemodynamically significant patent ductus arteriosus (hsPDA), patent ductus arteriosus (PDA) requiring ligation, severe BPD and severe extrauterine growth retardation (EUGR) were higher in PH group than those in non-PH group ((20.8% (5/24) vs. 6.4% (20/314), 33.3% (8/24) vs. 7.6% (24/314), 54.2% (13/24) vs. 7.3% (23/314), 25.0% (6/24) vs. 6.1% (19/314), 75.0% (18/24) vs. 39.2% (123/314), 45.8% (11/24) vs. 1.9% (6/314), 66.7% (16/24) vs. 7.3% (23/314), 75.0% (18/24) vs. 45.5% (143/314), all P<0.05). Multivariate logistic regression analysis showed that maternal hypertension (OR=12.950, 95%CI: 1.740-96.385), severe bronchopulmonary dysplasia (OR=10.160, 95%CI: 2.725-37.884), SGA (OR=4.992, 95%CI: 1.432-16.920), PDA requiring ligation (OR=19.802, 95%CI: 3.297-118.921), severe EUGR (OR=20.316, 95%CI: 2.221-185.853) were independent risk factors of BPD associated PH. In the 24 infants with PH, all 7 mild PH infants and 8 moderate PH infants survived, while 4 out of 9 severe PH infants died. Among the survivors, the longest duration of oxygen therapy was up to the corrected gestational age of 1 year and 2 months. Conclusions: PH is a severe complication of BPD, and associated with higher mortality and poor prognosis. Echocardiography screening and regular post-discharge follow up are recommended for BPD infants with risk factors of PH.

Progranulin promotes osteogenic differentiation of human periodontal ligament stem cells via tumor necrosis factor receptors to inhibit TNF-α sensitized NF-kB and activate ERK/JNK signaling

OBJECTIVE

To investigate the molecular mechanism of Progranulin (PGRN) in promoting osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) in inflammatory environment.

BACKGROUND

Progranulin is an antagonist of tumor necrosis factor (TNF) receptors (TNFRs) and is known to promote inflammatory periodontal bone defect regeneration.

METHODS

TNFR1- and TNFR2-silenced hPDLSCs designed as hPDLSCs-sh-TNFR1 and hPDLSCs-sh-TNFR2 were cultured with osteoinductive medium containing TNF-α and (or) PGRN. Immunofluorescence, quantitative real-time PCR, and western blot were used to, respectively, detect expressions of TNFR1\TNFR2 and osteogenic differentiation markers as well as phosphorylation level in NF-κB\MAPK-related pathways.

RESULTS

Immunofluorescence and real-time PCR showed that TNFR1 and TNFR2 positively expressed in hPDLSCs. TNF-α stimulation could significantly decrease the expressions of ALP and RUNX2 in hPDLSCs, whereas PGRN treatment could significantly enhance their expressions, and reverse TNF-α-mediated expression suppression of ALP and RUNX2 in hPDLSCs. In hPDLSCs-sh-TNFR1, TNF-α mediated osteogenic inhibition decreased, but both TNF-α + PGRN and alone PGRN significantly promoted expression of ALP and RUNX2. PGRN significantly enhanced expression of P-ERK1/2 and P-JNK, while corresponding inhibitors eliminated PGRN-stimulated osteogenic differentiation. In hPDLSCs-sh-TNFR2, no significant difference existed in osteogenic markers and P-JNK expression between the PGRN group and the control group. However, PGRN still activated P-ERK1/2 expression. Besides, PGRN antagonized TNF-α-enhanced NF-κB P65 expression.

CONCLUSION

Progranulin promotes osteogenic differentiation of hPDLSCs via TNFR1 to inhibit TNF-α-sensitized NF-κB and via TNFR2 to activate JNK signaling. The mechanism by which PGRN activates ERK signaling remains to be explored.

Tumor necrosis factor-alpha inhibits osteogenic differentiation of pre-osteoblasts by downregulation of EphB4 signaling via activated nuclear factor-kappaB signaling pathway

BACKGROUND AND OBJECTIVE

The majority of experiments show that tumor necrosis factor-alpha (TNF-α) inhibits osteogenic differentiation of mesenchymal stem cells and pre-osteoblasts by activated nuclear factor-kappaB (NF-κB) signaling. However, the underlying mechanisms by which NF-κB signaling inhibits osteogenic differentiation are not fully understood. The aim of the present study was to investigate whether EphB4 signaling inhibition mediates the effects of TNF-α-activated NF-κB signaling on osteogenic differentiation of pre-osteoblasts.

MATERIAL AND METHODS

Murine MC3T3-E1 pre-osteoblasts were treated with 10 ng/mL of TNF-α. NF-κB inhibitor, pyrrolidine dithiocarbamate, was used to achieve NF-κB signaling inhibition. EphB4 signaling was activated using ephrinB2-fc. The mRNA expressions of runt related transcription factor 2 (Runx2), bone sialoprotein (BSP) and EphB4 were determined using reverse transcription-polymerase chain reaction. The protein levels of Runx2, BSP, Col Ia1, osteopontin, EphB4, p-NF-κB p65 and NF-κB p65 were evaluated using western blot assays. Alkaline phosphatase (ALP) activity in MC3T3-E1 cells was evaluated by ALP activity kit, and mineral nodule formation was evaluated by Alizarin Red S staining.

RESULTS

TNF-α inhibited EphB4 expression, while it suppressed Runx2, BSP expression from gene and protein levels as well as ALP activity and mineral nodule formation in MC3T3-E1 cells. Activation of EphB4 signaling by ephrinB2-fc promoted osteogenic differentiation of MC3T3-E1 cells, whereas TNF-α impaired the osteogenic differentiation enhanced by ephrinB2-fc. Pyrrolidine dithiocarbamate blocked the activation of NF-κB signaling induced by TNF-α, while it prevented the downregulation of Runx2, BSP and EphB4, induced by TNF-α.

CONCLUSION

TNF-α inhibits osteogenic differentiation of pre-osteoblasts by downregulation of EphB4 signaling via activated NF-κB signaling pathway.

[Risk factors for lower extremity amputation in patients with diabetic foot]

Objective: To explore the risk factors for lower extremity amputation in patients with diabetic foot. Methods: The clinical data of 1 771 patients with diabetic foot at the Air Force General Hospital of PLA from November 2001 to April 2015 were retrospectively analyzed. The patients were divided into the non-amputation and amputation groups. Within the amputation group, subjects were further divided into the minor and major amputation subgroups. Binary logistic regression analyses were used to assess the association between risk factors and lower extremity amputation. Results: Among 1 771 patients with diabetic foot, 323 of them (18.24%) were in the amputation group (major amputation: 41; minor amputation: 282) and 1 448 (81.76%) in the non-amputation group. Compared with non-amputation patients, those in the amputation group had a longer hospital stay and higher estimated glomerular filtration rate(eGFR)levels. Fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), C-reaction protein (CRP), ESR, ferritin, fibrinogen and WBC levels of the amputation group were higher, while hemoglobin albumin, transferrin, TC, TG, HDL-C and LDL-C were lower than those of the non-amputation group (all P<0.05). The proportion of hypertension(52.48% vs 59.98%), peripheral vascular disease (PAD)(68.11% vs 25.04%), and coronary heart disease(21.33% vs 28.71%)were different between the amputation and non-amputation groups (all P<0.05). Multivariable logistic regression analyses showed that Wagner's grade, PAD and CRP were the independent risk factors associated with lower extremity amputation in hospitalized patients with diabetic foot. Conclusion: Wagner's grade, ischemia of lower limbs and infection are closely associated with amputation of diabetic foot patients.

[Forensic Analysis of 95 Nasal Bone Fracture Cases Caused by Blunt Instrument]

OBJECTIVES

To explore the characteristics of nasal bone fracture caused by blunt instrument, including the fracture types, the fracture repair, and the difference of manifestations between X-ray and CT. To provide reference for the identification.

METHODS

The information of basic situation, fracture site, injury manner, diagnosis method, expert opinion of 95 adult nasal fracture cases caused by blunt object, which occurred in Gutian county of Fujian province from January 1999 to December 2013, were analyzed by descriptive statistics. The identification conclusions of different injuries were compared according to new and old standards as well.

RESULTS

There were total 95 adults including 87 male and 8 female. The fracture site and quantity have significant correlation with the nasal bone anatomical relations and the direction and size of the force. Compound fracture was most common. The fracture that could not be determined by X-ray could be clearly diagnosed by CT examination. According to new and old standards, different fracture types have different identification conclusions.

CONCLUSIONS

There are gender differences in nasal bone fracture cases. Larger external force is easy to cause compound fracture. CT examination is significantly better than X-ray examination.

Network spatio-temporal analysis predicts disease stage-related genes and pathways in renal cell carcinoma

The purpose of this study was to screen the key genes and pathways of renal cell carcinoma (RCC) and lay the foundation for its diagnosis and therapy. Microarray data of normal subjects and RCC patients at different stages of disease were used to screen differentially expressed genes (DEGs). Based on the DEGs in the four disease stages, four co-expression networks were constructed using the Empirical Bayes method and hub genes were obtained by centrality analysis. The enriched pathways of the DEGs and the mutual hub genes in the cluster of each disease stage were investigated. The mutual hub genes of the four disease stages in RCC tissue were validated using reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. A total of 432 DEGs were screened, including 233 upregulated and 199 downregulated genes, by statistical analysis. Centrality analysis of co-expression networks in different disease stages suggested that PLXDC1, IKZF1, RUNX2, and RNF125 were mutual hub genes. Pathway analysis showed that the DEGs were significantly enriched in seven terms. The hub modules in stage I disease were significantly enriched in the complement coagulation cascade pathway and the hub modules of the other three disease stages were enriched in natural killer cell-mediated cytotoxicity. The expression levels of PLXDC1, IKZF1, RUNX2, and RNF125 were significantly different between normal subjects and RCC patients by RT-PCR and western blot. Our study revealed four hub genes (PLXDC1, IKZF1, RUNX2, and RNF125) and two biological pathways that might be underlying biomarkers involved in RCC.

Systemic BMSC homing in the regeneration of pulp-like tissue and the enhancing effect of stromal cell-derived factor-1 on BMSC homing

Pulp regeneration caused by endogenous cells homing has become the new research spot in endodontics. However, the source of functional cells that are involved in and contributed to the reconstituting process has not been identified. In this study, the possible role of systemical BMSC in pulp regeneration and the effect of stromal cell-derived factor-1 (SDF-1) on stem cell recruitment and angiogenesis were evaluated. 54 mice were divided into three groups: SDF-1 group (subcutaneous pockets containing roots with SDF-1 absorbed neutralized collagen gel and the green fluorescent protein (GFP) positive BMSCs transplantation via the tail vein), SDF-1-free group (pockets containing roots with gel alone and GFP + BMSCs transplantation) and Control group (pockets containing roots with gel alone). The animals were sacrificed after the roots were implanted into subcutaneous pockets for 3 weeks. Histomorphometric analysis was performed to evaluate the regenerated tissue in the canal by hematoxylin and eosin (HE) staining. The homing of the transplanted BMSCs was monitored with a fluorescence microscope and immunohistochemical analysis. The expression of ALP in new formed tissue was detected immunohistochemically. Dental-pulp-like tissue and new vessels were regenerated and GFP-positive BMSCs and expression of ALP could be observed in both SDF-1 group and SDF-1-free group. Furthermore, more GFP+ cells, stronger expression of ALP and stronger angiogenesis were found in the SDF-1 group than in the SDF-1-free group. To conclude, systemic BMSC can home to the root canal and participate in dental-pulp-like tissue regeneration. Intracanal application of SDF-1 may enhance BMSC homing efficiency and angiogenesis.

[Activation of transcription factor NF-κB in a rat model of cardiac fibrosis induced by β-adrenoceptor stimulation]

OBJECTIVE

To establish a model of cardiac fibrosis induced by isoproterenol (ISO), the non-selective β adrenoceptor agonist, injected subcutaneously for 7 days in rats, and to observe changes of transcription factor NF-κB in the model.

METHODS

Male SD rats weighing 280-320 g were injected with ISO (0.25 mg/kg/d) subcutaneously for 7 days to induce cardiac fibrosis. The collagen volume fraction was determined by quantitative morphometry of picrosirius red stained left ventricular sections. Collagen types I/III and IL-6 mRNA expressions were analyzed by real time PCR. The pathological changes of the heart were investigated by Hematoxylin and Eosin staining. NF-κB was localized by immunohistochemistry (IHC) and phosphorylated NF-κB levels were assessed by Western blot analysis.

RESULTS

Compared with the controls, ISO significantly elevated the sirius red stained area and collagen volume fraction (12.01±1.644 vs. 0.95±0.067, P<0.001). Similarly, ISO increased the mRNA expressions of collagen Iand collagen III of the heart compared with the controls (10.51±0.47 vs. 0.98±0.02,P<0.001 for collagen I; 9.58±1.33 vs. 1.02±0.02, P<0.001 for collagen III). The number of nuclei was increased and nuclear accumulation was presented in myocardial tissue induced by ISO. The mRNA expression of IL-6 increased in ISO group (1.64±0.18 vs. 1.04±0.07, P<0.01). ISO induced NF-κB nuclear translocation, accompanied by an increase in phosphorylation of NF-κB (10.83±2.05 vs. 1.05±0.27, P<0.001).

CONCLUSION

We conclude that the model of cardiac fibrosis can be successfully induced by ISO injected subcutaneously for 7 days in rats and the activation of nuclear factor NF-κB increased by β-adrenoceptor stimulation.

[Establishment of a FVB/N mouse model of cardiac hypertrophy by isoprenaline]

OBJECTIVE

To investigate the condition of isoprenaline (ISO)-induced cardiac hypertrophy in the FVB/N mouse.

METHODS

ISO (30 mg/kg/d) was administered either by daily subcutaneous injection, or by continuous infusion via an implanted osmotic minipump. The mice in each mode of administration were randomly divided into two groups. For subcutaneous injection: the mice received ISO or saline through daily subcutaneous injection for 2 weeks. The mice for minipump: the mice received continuous infusion of ISO via an implanted osmotic minipump for 2 weeks, or received sham operation as the control to mimipump. The ratio of heart weight to tibia length (HW/TI), the diastolic left ventricular posterior wall thickness (dLVPW) were used to indicate cardiac hypertrophy. Interstitial fibrosis was examined with picrosirius red staining.

RESULTS

ISO (30 mg/kg/d) administered by daily subcutaneous injection did not lead to cardiac hypertrophy or fibrosis in the FVB/N mice, and 50% of the mice died before the end point. The mice receiving ISO via minipumps showed significant increase in HW/TI [(10.60±0.40 ) mg/mm vs. (7.93±0.19) mg/mm,P<0.001] and dLVPW [(0.87±0.03) mm vs. (0.68±0.06)mm,P=0.0116]. ISO administered via minipumps did not induce cardiac fibrosis. All the mice in this group survived to the end point.

CONCLUSION

ISO (30 mg/kg/d) administered by continuous infusion via a minipump for 2 weeks can lead to significant cardiac hypertrophy.

GDF15 is a potential predictive biomarker for TPF induction chemotherapy and promotes tumorigenesis and progression in oral squamous cell carcinoma

BACKGROUND

Randomized trials have not shown major survival benefits when induction chemotherapy plus standard therapy is compared with standard therapy alone in patients with oral squamous cell carcinoma (OSCC). Induction chemotherapy is likely to be effective for biologically distinct subgroups and biomarker development may lead to identification of patients whose tumors are likely to respond to a particular treatment.

PATIENTS AND METHODS

We evaluated immunohistochemical staining for GDF15 in pretreatment biopsy specimens of 230 of 256 OSCC patients who were treated in a prospective, randomized, phase III trial on induction chemotherapy including docetaxel, cisplatin and 5-fluorouracil (TPF). Relationship between GDF15 intervention and cell proliferation, migration, invasion, colony formation and tumorigenicity was analyzed using in vitro and in vivo OSCC models.

RESULTS

Low GDF15 expression predicted a better survival in OSCC patients, especially overall survival [P = 0.049, hazard ratio (HR) = 0.597] and distant metastasis-free survival (DMFS; P = 0.031, HR = 0.562). cN+ patients with low GDF15 expression benefitted from induction TPF in overall survival (P = 0.039, HR = 0.247) and DMFS (P = 0.039, HR = 0.247), cN- patients with high GDF15 expression benefitted from induction TPF in overall survival (P = 0.019, HR = 0.231), disease-free survival (P = 0.011, HR = 0.281), locoregional recurrence-free survival (P = 0.035, HR = 0.347) and DMFS (P = 0.009, HR = 0.197). Decreased GDF15 expression in OSCC lines significantly inhibited cell proliferation, migration, invasion, colony formation and tumorigenesis through increased phosphorylation of AKT and ERK1/2 (P < 0.05). Likewise, overexpression of GDF15 significantly promoted cell proliferation, migration, invasion and colony formation through decreased phosphorylation of AKT and ERK1/2 (P < 0.05).

CONCLUSIONS

GDF15 expression can be used as a prognostic biomarker for OSCC, and as a predictive biomarker for benefitting from TPF induction chemotherapy. GDF15 promotes tumorigenesis and progression through phosphorylation of AKT and ERK1/2 in OSCC. The clinical trial in this study was registered with www.ClinicalTrials.gov (NCT01542931).

Elevated level of serum growth differentiation factor 15 is associated with oral leukoplakia and oral squamous cell carcinoma

BACKGROUND

Although molecular mechanism of growth differentiation factor 15 (GDF15) in tumorigenesis of oral squamous cell carcinoma (OSCC) is not clear, the diagnostic and prognostic value of serum GDF15 detection has been noticed. However, serum GDF15 levels in patients with oral leukoplakia and GDF15 as a potential predictive biomarker for response to induction chemotherapy in patients with OSCC have not been reported.

METHODS

Pretreatment serum GDF15 concentration was detected using an enzyme-linked immunosorbent assay in 30 healthy persons, 24 patients with oral leukoplakia, and 60 patients with OSCC.

RESULTS

Serum GDF15 concentration was significantly higher in patients with oral leukoplakia and OSCC, compared with healthy controls (F = 13.701, df = 2, P < 0.001). From a diagnostic standpoint, a cutoff value of 346.9 ng/l of serum GDF15 concentration was calculated using receiver operating characteristic curve, with a sensitivity of 0.750, specificity of 0.867, Youden's Index of 0.617, and area under curve of 0.863. From a prognostic standpoint, patients with serum GDF15 concentration <346.9 ng/l had an improved 3-year disease-free survival rate (64.3% vs 56.5%) compared with those above 346.9 ng/l, but the difference was not statistically significant. A decreased concentration of GDF15 (<346.9 ng/l) showed a predictive trend toward an improved response to induction chemotherapy compared with elevated concentration with clinical response rates of 100% and 71.4%, respectively, but the difference was not significant.

CONCLUSION

Elevated GDF15 level may be not only a diagnostic biomarker for oral leukoplakia, but also a prognostic/predictive biomarker associated with decreased survival and diminished response to induction chemotherapy for patients with OSCC.

Elevated cyclin D1 expression is predictive for a benefit from TPF induction chemotherapy in oral squamous cell carcinoma patients with advanced nodal disease

Induction chemotherapy is likely to be effective for biologically distinct subgroups of patients with cancer with biomarker detection. To investigate the prognostic and predictive values of cyclin D1 expression in patients with oral squamous cell carcinoma (OSCC) who were treated in a prospective, randomized, phase III trial evaluating standard treatment with surgery and postoperative radiotherapy preceded or not by induction docetaxel, cisplatin, and 5-fluorouracil (TPF), immunohistochemical staining for cyclin D1 was conducted in pretreatment biopsy specimens of 232 out of 256 clinical stage III/IVA OSCC patients randomized to the clinical trial. Cyclin D1 index was estimated as the proportion of tumor cells with cyclin D1 nuclear staining. A low cyclin D1 expression predicted significantly better overall survival (OS; P = 0.001), disease-free survival (P = 0.005), locoregional recurrence-free survival (P = 0.003), and distant metastasis-free survival (DMFS; P = 0.002) compared with high cyclin D1 expression. Cyclin D1 expression levels were not predictive of benefit from induction TPF in the population overall. However, patients with nodal stage cN2 whose tumors had high cyclin D1 expression treated with TPF had significantly greater OS (P = 0.025) and DMFS (P = 0.025) when compared with high cyclin D1 cN2 patients treated with surgery upfront. Patients with low cyclin D1 level or patients with cN0 or cN1 disease did not benefit from induction chemotherapy. This study indicates that cN2 OSCC patients with high cyclin D1 expression can benefit from the addition of TPF induction chemotherapy to standard treatment. Cyclin D1 expression could be used as a biomarker in further validation studies to select cN2 patients that could benefit from induction therapy.

XIAP is a predictor of cisplatin-based chemotherapy response and prognosis for patients with advanced head and neck cancer

Background

Approximately 60–80% of patients with advanced head and neck squamous cell carcinoma (HNSCC) die within five years after diagnosis. Cisplatin-based chemotherapy is the most commonly used palliative treatment for these patients. To evaluate the prognostic value of X-linked inhibitor of apoptosis (XIAP) level as a potential biomarker in these patients, we investigated the relationship between XIAP expression and cisplatin response of these patients and their prognosis.

Methodology/Principal Findings

Sixty patients with advanced HNSCC were recruited in this study. Expression of XIAP was examined both before and after chemotherapy and was correlated with chemotherapy response, clinicopathology parameters and clinical outcomes of the patients. We found that XIAP was expressed in 17 (20.83%) of the 60 advanced HNSCC samples and the expression was significantly associated with cisplatin resistance (P = 0.036) and poor clinical outcome (P = 0.025). Cisplatin-based chemotherapy induced XIAP expression in those post-chemotherapy samples (P = 0.011), was further associated with poorer clinical outcome (P = 0.029). Multivariate analysis demonstrated that only alcohol consumption, lymph node metastasis and XIAP level were independently associated with the prognosis of advanced HNSCC patients. Inhibiting XIAP expression with siRNA in XIAP overexpressed HNSCC cells remarkably increased their sensitivity to cisplatin treatment to nearly a 3 fold difference.

Conclusions/Significance

Our results demonstrate that XIAP overexpression plays an important role in the disease course and cisplatin-resistance of advanced HNSCC. XIAP is a valuable predictor of cisplatin-response and prognosis for patients with advanced head and neck cancer. Down-regulation of XIAP might be a promising adjuvant therapy for those patients of advanced HNSCC.

[Study on oral Candida albicans apoptosis in vitro]

PURPOSE

Candida albicans is one of the main opportunistic pathogen for human , the aim of this study is to investigate the phenomena of apoptosis in oral Candida albicans induced by acetic acid.

METHODS

The Candida albicans of clinical strains were induced to apoptosis by using a weak acid acetic acid.The apoptosis was detected by flow cytometry and TEM. The data were processed for Chi-square test using SPSS11.5 software package.

RESULTS

Oral Candida albicans had classic apoptosis when induced by proper concentration of acetic acid, and different concentrations of acetic acid had variable ability of inducing apoptosis of Candida albicans.

CONCLUSIONS

Apoptosis can be detected in clinical strains of Candida albicans, the mechanism of apoptosis needs further research for the purpose of developing new antifungal drugs. Supported by National Natural Science Foundation of China(Grant No.30400498) and 2007 National College Student Innovative Planning Project.

Starch properties of mutant rice high in resistant starch

As the staple food of over half the world's population, hot cooked rice high in resistant starch (RS) is of particular interest, which will have greater impact in the dietary prevention of diabetes and hyperlipidemia. A mutant rice high in RS in hot cooked rice, described as RS111, was comparatively studied with the wild type and common rice. Despite obviously low RS content in the raw milled rice, the RS content in the hot cooked rice of mutant RS111 was significantly higher than that of the wild type and common rice and, correspondingly, in vitro starch hydrolysis by porcine pancreatic alpha-amylase tends to be incomplete with low hydrolysis extent for the cooked mutant rice high in RS. Obvious differences in physicochemical properties, starch granule morphology, pasting properties, thermal properties, and X-ray diffraction pattern were observed among the mutant RS111, wild type, and common indica rice. The high-RS mutant was characterized by significantly higher apparent amylose content and crude lipid content, higher percentage of oval-shaped granules and bigger oval size, reduced paste viscosity, and low onset temperature, peak temperature, final temperature, enthalpy of gelatinization, and crystallinity.

[Assay of Epstein-Barr virus in nasopharyngeal tissues and serum of patients with nasopharyngeal carcinoma]

OBJECTIVE

Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC). Determination of EBV-VCA-IgA, EBV-EA-IgA in serum and assay of EBV DNA (PCR) in biopsy tissue has been used for diagnosis of NPC. This paper evaluated the value of the three determinations for diagnosis of NPC.

METHOD

146 patients were investigated. For each patient determination of EBV-VCA-IgA, EBV-EA-IgA in serum and EBV-DNA (PCR) in biopsy tissue were performed with double-blind studies, of 146 patients, 76 were NPC and 70 non nasopharyngeal carcinoma as control, identified with histopathological examination. The differences of the determinations between NPC and control were compared statistically with chi 2-test.

RESULT

Of 76 NPC, the positive rates of EBV-DNA (PCR), EBV-VCA-IgA and EBV-EA-IgA were 90.8%, 75.0% and 26.3% respectivelly. For 70 control cases, the positive rates 2.9%, 38.6% and 2.9% respectivelly (P < 0.005).

CONCLUSION

Our results suggested that assay of EBV-DNA (PCR) has better sensitivity and specificity than EBV-VCA-IgA and EBV-EA-IgA for diagnosis of NPC.

[Parapharyngeal space neoplasms]

OBJECTIVE

To explore the diagnose and management of parapharyngeal space (PPS) neoplasms.

METHOD

Records of 48 patients with PPS neoplasms operated from 1988 to 1998 were reviewed.

RESULT

Neurogenic tumors were the most common neoplasma in primary PPS neoplasms. CT and MRI could provide clinically informations such as their size, shape, extent and site. Tumor vessels could be clearly seen by carotid arteriography. The majority of PPS tumors were resected by a transcervical approach.

CONCLUSION

CT and/or MRI are essential for diagnose and presurgical planning, Arteriography can be used only when CT or MRi suggest a glomous tumor, or possible involvement of carotid artery, or when those tumors put the carotid artery at a risk for surgical injury. Transoral approach may be used for small tumors and transparotid approach may be especially indicated for removing deep lobe parotid tumors with extention to the PPS. When there is a significant risk for injury the internal carotid artery radiological evidence are necessary for infratemporal approach.

ADP-ribosylation factor 6 (ARF6) defines two insulin-regulated secretory pathways in adipocytes

ADP-ribosylation factor 6 (ARF6) appears to play an essential role in the endocytic/recycling pathway in several cell types. To determine whether ARF6 is involved in insulin-regulated exocytosis, 3T3-L1 adipocytes were infected with recombinant adenovirus expressing wild-type ARF6 or an ARF6 dominant negative mutant (D125N) that encodes a protein with nucleotide specificity modified from guanine to xanthine. Overexpression of these ARF6 proteins affected neither basal nor insulin-regulated glucose uptake in 3T3-L1 adipocytes, nor did it affect the subcellular distribution of Glut1 or Glut4. In contrast, the secretion of adipsin, a serine protease specifically expressed in adipocytes, was increased by the expression of wild-type ARF6 and was inhibited by the expression of D125N. These results indicate a requirement for ARF6 in basal and insulin-regulated adipsin secretion but not in glucose transport. Our results suggest the existence of at least two distinct pathways that undergo insulin-stimulated exocytosis in 3T3-L1 adipocytes, one for adipsin release and one for glucose transporter translocation.

Body distribution in mice of intravenously injected camptothecin solid lipid nanoparticles and targeting effect on brain

The objective of the present study was to investigate the specific drug targeting of anticarcinogenic drugs, such as camptothecin (CA), after intravenous (i.v.) injection by incorporation into solid lipid nanoparticles (SLN). A CA loaded SLN suspension consisted of 0.1% (w/w) camptothecin, 2.0% (w/w) stearic acid, 1.5% (w/w) soybean lecithin and 0.5% (w/w) polyoxyethylene-polyoxypropylene copolymer (Poloxamer 188) was prepared by high pressure homogenization. In vitro drug release was investigated in pH 7.4 phosphate-buffered saline at 37 degrees C. The concentrations of camptothecin in various organs were determined using reversed-phase high-performance liquid chromatography with a fluorescence detector after i.v. administration of CA-SLN and a camptothecin control solution (CA-Sol). The results showed that the CA-SLN had an average diameter 196.8 nm with a Zeta potential of -69.3 mV and in vitro drug release was achieved for up to a week. In tested organs, the AUC/dose and the mean residence times (MRT) of CA-SLN were much higher than those of CA-Sol, especially in brain, heart and reticuloendothelial cells containing organs. The brain AUC ratio of CA-SLN to CA-Sol was the highest among the tested organs. These results indicate that SLN are a promising sustained release and drug targeting system for lipophilic antitumour drugs, and may also allow a reduction in dosage and a decrease in systemic toxicity.

Subcellular distribution and differential expression of endogenous ADP-ribosylation factor 6 in mammalian cells

ADP-ribosylation factor (ARF) 6 has been shown to play a role in vesicular transport; however, the expression and subcellular localization of the endogenous protein have not been clearly delineated. In this study, an ARF6-specific monoclonal antibody was raised and used to examine the subcellular distribution and expression of ARF6 in various tissues and during the differentiation of several well characterized cell types. We found that ARF6 localizes in both the cytosol and membranes of all tissues and cells tested. Moreover, ARF6 in 3T3-L1 adipocytes is principally localized on the plasma membrane, but substantial amounts are detected in the cytosolic and intracellular membrane fractions. We observed an increased expression of ARF6 during the differentiation of B lymphocytes to plasmocytes. However, the expression of ARF6 decreased during adipogenesis and monocyte differentiation. In contrast, the expression of other ARFs, detected by the monoclonal antibody 1D9, did not significantly change during differentiation of the aforementioned cell types. Taken together, our results indicate that ARF6 is a broadly expressed, differentially regulated GTPase that is present in cytoplasm and on both cell-surface and intracellular membranes and whose functions may include tissue-specific effects on vesicular trafficking during cellular differentiation.

Reconstitution of phagosome-lysosome fusion in streptolysin O-permeabilized cells

We have reconstituted fusion between phagosomes and lysosomes in streptolysin O-permeabilized J774-E macrophages. Fusion was assessed by measuring the delivery of avidin-conjugated horseradish peroxidase pre-internalized into lysosomes to phagosomes containing biotinylated beta-glucuronidase-conjugated paramagnetic beads (1-2 microm). Fusion was dependent on energy and exogenously supplied cytosol. Phagosome-lysosome fusion was greatly inhibited when microtubules were depolymerized by nocodazole treatment, suggesting that fusion occurs via microtubule-dependent transport. Furthermore, fusion was inhibited by GTPgammaS and Rab GDP dissociation inhibitor. These results suggest that rab proteins are involved in the regulation of fusion. Lastly, anti-NEM-sensitive factor (NSF) antibodies inhibited fusion, and addition of recombinant NSF wild type partially restored the fusogenic activity, indicating that NSF is required for fusion between phagosomes and lysosomes.

Physical property analysis and bacterial adhesion on a series of phosphonated polyurethanes

Glycerophosphorylcholine (GPC) was incorporated as the chain extender in a series of poly(tetramethylene oxide)-based polyurethane block copolymers. In order to determine the feasibility of use of these polyurethanes in biomedical devices, the effects of GPC incorporation on physical properties were studied. The effect of soft-segment molecular weight was also investigated. Biocompatibility of these materials was studied with regard to bacterial adhesion and protein deposition. Tensile testing showed that as GPC content increased, elongation at break decreased, while Young's modulus increased. Differential scanning calorimetry (DSC) results showed slightly decreased glass transition temperatures (Tgs) with increasing GPC content, indicating increased phase separation. Dynamic mechanical analysis (DMA) confirmed the decrease in Tg and the increase in rubbery plateau modulus with increasing GPC content. Water absorption was also increased with GPC content. Decreased bacterial adhesion was found on the GPC-containing materials compared to other functionalized polyurethanes. These experiments were carried out in a radial flow chamber utilizing automated video microscopy. Bacterial attachment was found to be lower on the GPC-containing polyurethanes both in the absence of and after pre-adsorption with plasma proteins.

[Mechanisms of resistance to melphalan in leukemia cell line and reversal by interferon alpha]

OBJECTIVES

To study the mechanisms of resistance to alkylating agent melphalan (Mel) in leukemia cell and to investigate effect of modulation of resistance to Mel by IFN alpha.

METHODS

A Mel-resistant variant of the leukemic cell line (K562/Mel) was developed in vitro by continuous exposure to Mel. The level of expression of several resistance-related gene in K562/Mel and the effect of reversal of resistance to Mel by IFN alpha were observed.

RESULTS

K562/Mel was 8.0-fold resistant to Mel and also cross-resistant to nitrogen mustand and thiophosphoramide, but not to carmustine and doxorubicin. This enhanced Mel resistance was associated with increased level of GST alpha gene and total GST, but not with increased level of expression of GST pi, GST mu, MDR-1 and Top-II gene. IFN alpha, at 500 IU/ml, a noncytotoxic dosage significantly increased the cytotoxicity of Mel to K562/Mel. The reversal of Mel resistance is related to the decrease of the level of expression of GST alpha gene.

CONCLUSION

Resistance to Mel is associated with increased level of GST alpha gene and total GST in leukemic cell. IFN alpha can reverse Mel resistance.

Multidrug resistance in leukemic cell line K562/A02 induced by doxorubicin

AIM

To study the mechanism of the development of multidrug resistance in leukemic cells.

METHODS

A human leukemic cell line K562/A02 was established by stepwise increase of concentrations of doxorubicin (Dox) in medium. P-glycoprotein was detected by immunohistochemistry assay. The mdr1 gene expression was measured by RT-PCR. The amplification of mdr1 gene in its genome, and DNA topisomerase II (Top II) gene expression were determined by dot-blot hybridization.

RESULTS

K562/A02 was highly cross-resistant to vincristine (VCR), homoharringtonin (HHT), amsacrine (m-AMSA), daunorubicin (Dau) and etoposide (VP-16), slightly to cytosine arabinoside (Ara-C), but not cisplatin (Cis), methotrexate (MTX) and fluorouracil (5-FU), showing a typical phenotype of MDR. Intracellular accumulation of Dau in K562/A02 was 33% as high as that in K562. P-glycoprotein P-170 was positive. In K562/A02, the mdr1 gene did not amplify, the mdr1 mRNA level was markedly higher, the Top II mRNA level was lower, and glutathione-S-transferase (GST) activity was higher than in K562.

CONCLUSION

mdr1 mRNA was overexpression and thus the encoded P-170 was responsible for MDR in K562/A02 while Top II or GST may play a role in MDR.

[Detection and analysis of multidrug resistance in 100 cases of acute leukemia]

Bone marrow specimens from 100 cases of acute leukemia (AL) diagnosed by MIC were detected with fluorescence microscopy for their mdr-1 expression using monoclonal antibody JSB-1 against P-glycoprotein (P-170). The results showed that almost all subtypes of AL had P-170 expression and M5 of ANLL had a significantly higher expression rate in the newly diagnosed group. The MDR expression highly correlated with the clinical drug resistance and prognosis. The Positive rate of P-170 (20.8% +/- 14.9%) and MDR expression (78.9%) of refractory group were significantly higher than newly diagnosed group (7.5% +/- 9.8% and 18.2% respectively). Cases with MDR expression had poor response to chemotherapy and bad prognosis.

Synthesis, characterization and ex vivo evaluation of polydimethylsiloxane polyurea-urethanes

A series of segmented polydimethylsiloxane (PDMS) polyurea-urethanes was synthesized based on hexane diisocyanate modified polyether-PDMS soft segments. The hard segments consisted of 4,4'-methylene diphenylene diisocyanate, which was chain extended with 1,4-butanediol. The effect of chemical composition of the polyether-PDMS soft segments on the extent of phase separation, physical properties and surface properties was studied using a variety of techniques including dynamic mechanical analysis, tensile testing, X-ray photoelectron spectroscopy (XPS) and contact angle analysis. The polymers were also evaluated for their blood-contacting properties in a canine ex vivo model. The PDMS polyurea-urethanes containing polyether-PDMS soft segments showed three distinct phases: a PDMS-rich phase, a polyol soft segment-rich phase and a hard segment-rich phase. The tensile strength and modulus of these materials were not significantly lower compared to a polymer without PDMS in the soft segment. XPS revealed the surface enrichment of the hydrophobic PDMS component at the air-solid interface. Dynamic contact angle measurements indicated that the PDMS-based polyurea-urethanes possessed a hydrophobic surface in water. The PDMS polyurea-urethanes showed lower adherent platelet and fibrinogen deposition compared to a polymer without PDMS in the soft segment. Varying the amount of PDMS in the soft segment of these polymers did not reveal significant differences in their blood-contacting properties.

Species specificity and organ, cellular and subcellular localization of the 100 kDa Ras GTPase activating protein

A p100-GAP isoform, generated by an alternative splicing mechanism that eliminates the 180 hydrophobic amino acids at the amino terminus of p120-GAP, has been described in human placenta, in addition to the known p120GAP and neurofibromin. This p100-GAP possesses full Ras-GTPase stimulating activity. p120-GAP is ubiquitously localized in the cytosol while the localization of p100-GAP is unknown. Here we have explored the precise localization of p100-GAP and show that p100-GAP is present only in extracts of primate placenta. It is abundant in both human and Maccaca Rhesus placentae, where it is present in far larger amounts than p120-GAP. The p100-GAP is species-specific since it was not detected in the placenta of pig, sheep, mouse or rat. p100-GAP was also found to be organ-specific, since it was not detectable in organs other than the placenta. In this connection, we substantiated our previous finding that p100-GAP is mainly localized in the trophoblasts. Both subcellular trophoblast fractionation and immunofluorescence analyses showed that this protein was distributed between the cytosol, plasma membrane and a fraction bound to the nucleus, but not inside it. This highly restrictive specificity of p100-GAP localization in relation to species, organ and cell type, confirms the extreme singularity of this protein, and strongly suggests a particular specific function in the trophoblast.

The small GTP-binding protein rab6p is redistributed in the cytosol by brefeldin A

Rab6 protein belongs to the Sec4/Ypt/rab subfamily of small GTP-binding proteins involved in intracellular membrane trafficking in yeast and mammalian cells. Its localization both in medial and trans-Golgi network prompted us to study the effects of brefeldin A (BFA) on rab6p redistribution. By two techniques, indirect immunofluorescence and cell fractionation, we investigated the fate of rab6p and compared it to other Golgi or trans-Golgi network markers in BHK-21 and NIH-3T3 cells. BFA, at 5 micrograms/ml, induced redistribution of rab6p according to a biphasic process: during the first 10–15 minutes, tubulo-vesicular structures--colabelled with a bona fide medial Golgi marker called CTR 433--were observed; these structures were then replaced by punctate diffuse staining, which was stable for up to 3 hours. The 110 kDa peripheral membrane protein beta-COP was released much more rapidly from the Golgi membranes, whereas the trans-Golgi network marker TGN 38 relocated to the microtubule organizing center. The kinetics of reversion of BFA action on these antigens was also followed by immunofluorescence. Consistent with these results, rab6 antigen, originally found as 40% in the cytosolic versus 60% in the particulate (P 150,000 g) fraction, became almost entirely cytosolic; moreover, it partitioned in the aqueous phase of Triton X-114 whereas the membrane fraction was detergent-soluble. Rab6p did not become part of the coatomers after its BFA-induced release from Golgi structures. Three requirements seemed to be necessary for such a release: integrity of the microtubules, presence of energy, and a hypothetical trimeric G protein, as revealed by the respective roles of nocodazole, ATP depletion, and sensitivity to aluminium fluoride. Finally, we have shown that BFA does not prevent attachment of newly synthesized rab6p to membranes.

Separation of electronic and hydrophobic effects for the papain hydrolysis of substituted N-benzoylglycine esters

The role of hydrophobic and electronic effects on the kinetic constants kcat and Km for the papain hydrolysis of a series of 22 substituted N-benzoylglycine pyridyl esters was investigated. The series studied comprises a wide variety of substituents on the N-benzoyl ring, with about a 300,000-fold range in their hydrophobicities, and 2.1-fold range in their electronic Hammet constants (sigma). It was found that the variation in the log kcat and log 1/Km constants could be explained by the following quantitative-structure activity relationships (QSAR): log 1/Km = 0.40 pi 4 + 4.40 and log 1/kcat = 0.45 sigma + 0.18. The substituent constant, pi 4, is the hydrophobic parameter for the 4-N-benzoyl substituents. QSAR analysis of two smaller sets of glycine phenyl and methyl esters produced similar results. A clear separation of the substituent effects indicates that in the case of these particular esters, acylation appears to be the rate limiting catalytic step.

Increase in the expression of a family of small guanosine triphosphate-binding proteins, rab proteins, during induced phagocyte differentiation

Rab is a newly identified family of small G-proteins that share 35-70% homology with the yeast Sec4p and Ypt1p involved in the regulation of the secretory pathway. Mature phagocytes display functions requiring organized intracellular traffic and, for this reason, we questioned whether phagocyte differentiation could correlate with the increased expression of rab proteins. Rabbit antisera raised against the recombinant proteins rab1Ap, 2p, 4p, and 6p were able to detect the corresponding proteins in the human monoblast leukemic cell line U937. When these cells were induced to differentiate into monocyte/macrophage-like cells displaying functional characteristics of a normal phagocyte, rab1Ap, 2p, 4p, and 6p were increased and this correlated with an increase in the rab transcripts. Using a rab5 probe, we also observed an increased expression of the rab5 gene in differentiated cells. Similarly, differentiation of the human leukemic myeloblast HL60 cell line along either monocyte or granulocyte pathways induced an increased expression of the rab proteins. Rab proteins were also detected in human neutrophils and in guinea pig alveolar macrophages. As degranulation is one of the phagocyte functions acquired in the late stage of differentiation, we investigated whether rab proteins would be involved in this process. Although rab proteins were tightly membrane bound, none of them was detected in the specific or azurophil granules purified from human neutrophils. The increased expression of rab proteins in mature phagocytes suggests that they may promote functions highly developed in these cells.

The use of Chinese herb medicine in experimental radiotherapy

Extracts from a group of destagnative herbs, 764-1, and the effective chemical, 764-3, were tested by an in vitro experiment using a HeLa-S3 cell line. Under aerobic conditions, the shoulder of the cell survival curve diminished or disappeared according to the different doses of 764-1 used, but no change in slope was observed. In nitrogen, when the dose of 764-1 increased to 20 mg/ml (ID20), besides the disappearance of the shoulder, the slope of the curve also showed changes at lower doses (4-8 Gy); up to 10-25 Gy the curve became more flattened. 764-3 showed almost a similar effect by mainly affecting the shoulder of the survival curve. At low drug doses a SER as high as 1.87 might be obtained under hypoxic condition. At the same time 764-1 was used in testing the effect on radiation lung damage. It was found that 764-1 could markedly inhibit the change of alveolar surfactant at 1 and 3 weeks after radiation. A wide field of investigation is thus spread out in front of us on radiosensitization and protection. Further studies on 764-3 are carried out.

Chymotrypsin hydrolysis of X-phenyl hippurates. A quantitative structure-activity relationship and molecular graphics analysis

The hydrolysis of a set of 28 X-phenyl hippurates by chymotrypsin was investigated. From the derived Km and kcat values a quantitative structure-activity relationship was developed. This equation shows that para substituents correlated by sigma- display only an electronic effect on the formation of the ES complex whereas meta hydrophobic substituents show a hydrophobic interaction correlated by pi in addition to their electronic effect. Meta polar substituents avoid contact with the enzyme and show only electronic effects on Km. Using the x-ray crystallographic coordinates for chymotrypsin and computer graphics, a model was constructed which is used to interpret the quantitative structure-activity relationship. As with a number of previously reported examples, we have found that when polar substituents have the option of binding to hydrophobic space or remaining in the aqueous phase they follow the latter possibility.

Quantitative structure-activity relationships and molecular graphics in ligand receptor interactions: amidine inhibition of trypsin

Quantitative structure-activity relationships have been formulated for four sets of amidine inhibitors of trypsin. The quantitative results from these equations are compared with qualitative models constructed from the X-ray crystallographic coordinates of a benzamidine bound to trypsin. The good agreement between the mathematical and graphics models provides further support for the use of substituent constants and regression analysis in the study of enzyme-ligand interactions.

Luminal secretion of myo-inositol by the rat epididymis perfused in vitro

A technique for perfusing the lumen of rat epididymal tubules maintained in vitro showed that [3H]inulin was largely excluded from the lumen of unravelled tubules from the cauda and tubules from the corpus if the connective tissue capsule was removed. The preparation transported [3H]inositol from the bath fluid for 3 h against a concentration gradient in both regions with activity rising (16-29% of bath fluid values) in the cauda and reaching a plateau (18%) in the corpus epididymidis. HPLC showed that radioactivity was solely associated with inositol and its movement to the lumen was reduced by raising inositol in the bath fluid from 50 microM (plasma levels) to 10 mM, but not affected by reducing the glucose concentration in the bath fluid or introducing physiological concentrations of inositol (30 mM) into the lumen. Secretion into the caudal lumen of unlabelled inositol measured by g.l.c. was maintained for 3 h at concentrations (300 microM) greater than those in the bath fluid and was not reduced when glucose or inositol were removed from the bath. In contrast, glucose was only detectable in the lumen when it was present in the bathing medium, reaching 1% of this concentration. Radioactivity appeared in the epididymal lumen reaching a plateau (19% of bath fluid values) in the corpus and cauda when [3H]glucose was added to the bath fluid, but no radiolabelled inositol was found in the lumen. We conclude that epididymal tissue is a major source of secreted inositol.