Effect of PI3K/AKT/HIF-1α signaling pathway on oxidative stress and apoptosis in nucleus pulposus cells

OBJECTIVE

The aim of the study was to explore the expression of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT)/hypoxia-induced factor-1 alpha (HIF-1α) signaling pathway and the apoptosis of nucleus pulposus cells (NPCs) under different oxygen concentrations to clarify the biological characteristics of NPCs and the molecular mechanism of intervertebral disc degeneration (IVDD).

MATERIALS AND METHODS

Normal and degenerated human NPCs were collected. Leibovitz's medium with 100 μmol/L CoCl2 was used to establish a hypoxic culture environment, and 100 μmol/L H2O2 was used to establish an oxidative stress culture environment. Third-generation NPCs were divided into 6 groups: normal NPCs + hypoxia, normal NPCs + normoxia, normal NPCs + oxidative stress, degenerated NPCs + hypoxia, degenerated NPCs + normoxia, and degenerated NPCs + oxidative stress. Normal NPCs + hypoxia was used as the experimental control group. Cell viability and proliferation were detected by using the Cell Counting Kit-8 (CCK-8) method. Cell apoptosis rate was assessed by flow cytometry, and expression levels of PI3K, AKT, and HIF-1α were determined by Real-Time-Polymerase Chain Reaction (RT-PCR) and Western blotting.

RESULTS

The cell proliferation rate of both normal and degenerated NPCs decreased with increasing oxygen concentration. Conversely, the apoptosis rate increased as the oxygen concentration increased (p<0.05). Compared with the control group, whether the cells degenerated had a very significant impact on the apoptosis rate (p<0.001), and oxygen concentration also had a highly significant impact on both the cell proliferation rate and apoptosis rate (both p<0.001). The interaction between cell degeneration and oxygen concentration significantly affected both cell proliferation and apoptosis rates (p<0.05). Considering the expression levels of PI3K, AKT, and HIF-1α, normal NPCs had the highest levels under low oxygen concentrations, followed by oxidative stress and normoxia. In degenerated NPCs, the expression levels also decrease as the oxygen concentration increases.

CONCLUSIONS

The PI3K/Akt/HIF-1α signaling pathway plays a significant role in inhibiting oxidative stress, antagonizing NPC apoptosis, and consequently delaying IVDD.

[Epidemiological characteristics and analysis of related infection risk factors for influenza in Anhui Province from 2013 to 2021]

Objective: Analysis of the characteristics of influenza epidemic in Anhui Province and quantification of the impact of different factors on influenza occurrence, providing scientific basis for better influenza prevention and control. Methods: Descriptive analysis and factor analysis were conducted on influenza-like illness (ILI) cases and RT-PCR results in Anhui Province from 2013 to 2021 using data from China's Influenza Monitoring Information System. Results: The percentage of influenza-like illness (ILI%) of sentinel hospitals in Anhui Province from April 1, 2013 to March 31, 2021 was 3.80% (1 209 142/31 779 987), showing an overall increasing trend, with a relatively high proportion in 2017-2018 at 4.30% (191 148/4 448 211). The proportion of ILI cases in infants and young children aged 0-4 years was a relatively high at 54.14% (654 676/1 209 142), and the highest ILI% was observed in Fuyang City, Anhui Province (6.25%, 236 863/3 788 863). Laboratory monitoring results showed that the positive rate of ILI cases in sentinel hospitals in 8 influenza monitoring years was 16.38% (34 868/212 912), showing an increasing trend year by year, with a relatively proportion in 2017-2018 at 26.19% (6 936/26 488). The detection rate of school-age children aged 5-14 years was a relativelyhigh at 28.81% (13 869/48 144), and the positive rate was a relatively high in Wuhu City among the 16 cities, reaching 22.01% (2 693/122 237). Influenza activity showed a single peak in winter-spring and alternating double peaks in winter-spring and summer, with different subtypes alternating, and A (H3N2) was the dominant subtype in summer. The results of a multiple logistic regression model showed that the positive rate was higher in 2017-2018, among children aged 5-14 years, in winter, and in southern Anhui. Conclusions: Influenza epidemic in Anhui Province has a clear seasonal pattern, and the ILI% and detection rate have shown an upward trend from 2013 to 2021. Therefore, it is suggested to ensure vaccine supply before the winter-spring influenza season arrives, and to strengthen vaccine uptake and health education to avoid the risk of infection during the peak period of influenza.

[Analysis of the effect of stent-assisted embolization for low-grade subarachnoid hemorrhage caused by V4 segment dissecting aneurysm of vertebral artery]

Objective: To investigate the efficacy and safety of different stents assisted embolization in the treatment of subarachnoid hemorrhage(SAH) caused by V4 dissecting aneurysm of vertebral artery. Methods: The clinical data of 39 patients with spontaneous SAH V4 dissecting aneurysm treated at the Department of Neurosurgery, the Northern Theater General Hospital from January 2016 to June 2019 were analyzed retrospectively.There were 21 males and 18 females, aged (48±17) years(range:35 to 68 years).There were 24 cases of HUNT-HESS grade Ⅰ and 15 cases of grade Ⅱ.Among them, 20 cases were treated with single stent-assisted embolization, 9 cases with multi-stent-assisted embolization, 9 cases with semi-dense mesh-assisted embolization, and 1 case with dense-mesh stent-assisted embolization.The perioperative and postoperative complications, postoperative recurrence were collected. Results: Intraoperative complications included 2 cases of aneurysm rupture and 2 cases of acute thrombosis.All aneurysms were densely packed according to the angiography performed immediately after operation.Postoperative complications included 3 cases of long-term responsible vascular ischemia(modified Rankin score<2). The patients were followed up for 15.1 months(range: 12 to 29 months). At the last follow-up, aneurysms recurrence occured in 10 cases, the recurrence rate was 25.6%(10/39). There were 6 cases of recurrence and 2 cases of complications in 20 cases with single stent-assisted embolization, 3 cases of recurrence and 4 cases of complications in 9 cases with multi-stent-assisted embolization, 1 case of recurrence and 1 case of complications in 9 cases with semi-dense mesh stent. Conclusion: Endovascular treatment is feasible for patients with vertebral artery dissecting aneurysm, and the appropriate surgical method should be selected according to the vascular structure and the location of the aneurysm.

IL-6 stimulates lncRNA ZEB2-AS1 to aggravate the progression of non-small cell lung cancer through activating STAT1

OBJECTIVE

To illustrate the role of interleukin 6 (IL-6) in the progression of non-small cell lung cancer (NSCLC) via activating STAT1.

PATIENTS AND METHODS

The level of IL-6 mRNA in 48 paired NSCLC tissues and matched normal ones was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Kaplan-Meier curves were depicted for assessing the overall survival of NSCLC patients with high or low level of IL-6 mRNA. Subsequently, the ZEB2-AS1 level in A549 cells treated with different doses of IL-6 for different time points was determined. After A549 cells were treated with different doses of IL-6, wound closure assays were performed to assess the migration of cells. Protein levels of pSTAT1 and STAT1 in IL-6-treated A549 cells were detected by Western blot. The regulatory effect of STAT1 on IL-6-induced migration of A549 cells was also evaluated. The interaction between ZEB2-AS1 and STAT1 was explored through Chromatin Immunoprecipitation (ChIP) assay. Finally, the role of ZEB2-AS1/STAT1 axis in regulating NSCLC cells was investigated through rescue experiments.

RESULTS

Our results indicated that IL-6 was upregulated in NSCLC tissues and cancer cell lines. NSCLC patients with T3-T4 or accompanied with lymphatic metastasis had a higher IL-6 abundance than those with T1-T2 or without metastatic foci. The worse prognosis was identified in NSCLC patients with high expression of IL-6 compared to those with low expression. ZEB2-AS1 showed dose-dependent and time-dependent increase in IL-6-treated A549 cells. IL-6 treatment gradually enhanced the migration ability of A549 cells in a dose-dependent manner. In IL-6-treated A549 cells, protein level of pSTAT1 was remarkably upregulated, and knockdown of STAT1 significantly reversed the promotive effect of IL-6 on migration ability of A549 cells. The results of ChIP assay verified the interaction between ZEB2-AS1 and STAT1. In addition, ZEB2-AS1 could reverse the regulatory effect of STAT1 on the migration ability of A549 cells.

CONCLUSIONS

IL-6 was upregulated in NSCLC and accelerated the progression of NSCLC via activating STAT1/ ZEB2-AS1.

[Prevalence of HBV co-infection in HIV-positive population in China: a systematic review and Meta-analysis]

Objective: To reveal the epidemiologic characteristics of hepatitis B virus (HBV) infection in HIV positive population in China. Methods: We collected research papers published from 2010 to 2019 on HBV co-infection in HIV positive population in China through literature retrieval, screening and quality evaluation. The Meta-analysis was conducted after extracting relevant data from the research papers meeting the inclusion criteria. Results: Twenty-seven studies were included with 69 816 samples. The pooled HBV infection rate in HIV positive population in China was 11.29%. The HBV co-infection rate was higher in the western China (10.73%) and southern China (14.18%), while lower in northern China (6.36%). The HBV infection rates were 11.22%, 12.76%, 9.58%, 11.32% and 10.34%, respectively, in HIV-positive population infected through blood or blood products transfusion, intravenous drug use, homosexual contact, heterosexual contact and unknown transmission routes. Population infected with HIV caused by mother-to-child transmission had the lowest HBV infection rate (2.87%). The HBV infection rate in HIV positive males was 1.29 times higher than that in HIV positive females in southern China. Conclusions: The HBV infection rate in HIV positive population is significantly higher than that in general population. More attention should be paid to the prevention and control of HBV co-infection in HIV positive population.

MicroRNA-218 prevents lung injury in sepsis by inhibiting RUNX2

OBJECTIVE

To explore the regulatory effects of microRNA-218 on lung tissue of rats with acute lung injury (ALI) and its underlying mechanism.

MATERIALS AND METHODS

A total of 32 Sprague Dawley (SD) rats were randomly divided into control group, lung injury group and microRNA-218 treatment group. The in vitro lung injury model was established by injections of lipopolysaccharide (LPS), PGN (peptidoglycan) and IgG IC (immune complex). Polymerase Chain Reaction (PCR) was performed to detect the expression of microRNA-218 in lung tissues of ALI rats. Enzyme-Linked Immunosorbent Assay (ELISA) was used to measure the level of cytokine secretion in ALI rats. The activity and expression level of nuclear factor-kappa B (NF-κB) in MH-S and RA264.7 cells were determined by Luciferase activity assay and Western blot, respectively.

RESULTS

MicroRNA-218 was significantly down-regulated in bleomycin and IgG IC-induced lung injury rat model, as well as in cells treated with LPS, PGN and IgG IC. Inflammatory factors, including TNF-α, IL-1b, and IL-6, also showed increased in vivo and in vitro expressions. Besides, the overexpression of microRNA-218 inhibited the secretion of inflammatory factors. PCR analysis and Luciferase activity assay indicated that the expressions of RUNX2 and BIRC3 were down-regulated by microRNA-218 in MH-S and RA264.7 cells. Subsequent studies on mechanisms demonstrated that microRNA-218 inhibited the activity of the NF-κB pathway.

CONCLUSIONS

The expression of microRNA-218 markedly decreased in lung tissue of ALI rats, while the expression of inflammatory cytokines showed a remarkable increase, which might be related to the activation of RUNX2 and NF-κB.

[Cost-effectiveness analysis of rabies immunization strategy based on dynamic-decision tree model]

Objective: To evaluate the cost-utility of different immunization strategies for rabies in China, and to provide a reference for determining the optimal immunization strategy. Methods: The system dynamics model was used to simulate the epidemic of canine rabies and a decision tree model was conducted to analysis different immune strategies. Relevant probabilities were obtained through literature search and on-site investigation. Sensitivity analysis was used to explore the important influenced factors. Results: At baseline, from a social perspective, 70% vaccination of dogs was the optimal strategy compared to current vaccination strategy (43% vaccination in dogs, human category-Ⅱ exposure vaccination/category-Ⅲ exposure vaccination combined with RIG). The total cost was 14 084 354 CNY, and the total utility value was 22 078 616.23 QALYs, and the incremental cost-utility ratio was-62 148 147 CNY/QALY; if human vaccination was considered, 55% vaccination of dogs combined with strategy one was the optimal strategy, its incremental cost-utility ratio was-444 620 557 CNY/QALY. The probability that an injured dog carries rabies virus was the most sensitive parameter. When it was greater than 0.005 03, strategy four was the optimal strategy. When it was less than 82/100 000, strategy one was the optimal strategy; when it was between 82/100 000 and 120/100 000, strategy two was the optimal strategy; when it was between 120/100 000 and 503/100 000, strategy two was the optimal strategy. Conclusion: It was conducive to increase the vaccination coverage of canine for the prevention and control of rabies.

[IL-25-regulated type 2 innate lymphoid cells activation promote allergic fungal rhinosinusitis]

Objective: To investigate the regulation of IL-25 on type Ⅱ innate lymphoid cells (ILC2s) activation in the pathogenesis of allergic fungal rhinosinusitis (AFRS). Methods: Nasal mucosa tissues were collected from 16 AFRS patients and 12 patients, who underwent nasal endoscopic surgery for cerebrospinal rhinorrhea or skull base benign tumor during the period from June 2016 to June 2017 in Department of Rhinology, the First Affiliated Hospital of Zhengzhou University. Firstly, flow cytometry was used to detect ILC2s in nasal mucosa of both groups. Secondly, the expression of IL-25, IL-5 and IL-13 in nasal mucosa was detected by immunofluorescence and/or Western Blot assay. Finally, fungal extracts, IL-25 and glucocorticoids were used to stimulate nasal mucosal epithelial cells and tissues in vitro respectively to detect the regulatory effect of IL-25 on ILC2s. SPSS 16.0 software was used to analyze the data. Results: The prevalence of ILC2s in nasal tissues was higher in patients with AFRS than those of the control group ((3.85±1.52)%(Mean±SD) vs (0.32±0.10)%, U=9.00, P<0.05). There was a positive correlation between the prevalence of ILC2s and the number of eosinophils in nasal mucosa of patients with ARFS (r=0.80, P<0.05). The expression of IL-25, IL-5 and IL-13 in nasal mucosa epithelium of AFRS group was significantly higher than that of the control group (0.49±0.13 vs 0.23±0.09, 0.23±0.05 vs 0.10±0.04, 0.31±0.08 vs 0.14±0.07, t value was 5.90, 7.21, 5.69, respectively, all P<0.05). Fungal stimulation enhanced the expression of IL-25 protein in nasal epithelial cells of both groups (0.67±0.19 vs 0.25±0.12 (AFRS group), 0.62±0.17 vs 0.27±0.16 (control group), q value was 8.65, 9.26, respectively, all P<0.05). In the IL-25 stimulated nasal mucosa at a concentration of 1, 10 and 100 ng/ml, the expression level of retinoid acid-related orphan receptor α (RORα) mRNA was 2.07±1.53, 5.06±0.93, 7.38±2.30, respectively; the expression level of GATA binding protein 3 (GATA3) mRNA was 3.58±1.29, 6.14±1.55, 7.64±2.28, respectively; the expression level of IL-5 protein was 0.21±0.06, 0.32±0.06, 0.38±0.10, respectively; the expression level of IL-13 was 0.52±0.13, 0.69±0.22, 0.82±0.21, respectively, which were significantly higher than that in the unstimulated nasal mucosa (1.00±0.00, 1.00±0.00, 0.11±0.05, 0.35±0.15, F value was 63.45, 59.27, 49.35, 20.20, respectively, all P<0.05). The up-regulation could be inhibited by dexamethasone (F value was 89.20, 92.47, 99.63, 49.82, respectively, all P<0.05). Conclusions: Epithelial-derived IL-25 up-regulates the expression of IRC2s-dependent transcription factors RORα and GATA3 mRNA, which are positively correlated with elevated IL-13 and IL-5 expression levels in tissues, may be involved in AFRS inflammatory response, and are inhibited by glucocorticoids.

[Clinical analysis of combined treatment in 87 patients with recurrent allergic fungal rhinosinusitis]

Objective:To evaluate the effects of combined treatment with FESS on postoperative recurrent allergic fungal rhinosinusitis treatment.Method:Eighty-seven patients with allergic fungal sinusitis under combined treatment were investigated.Result:All patients were followed up for more than one year.Clinical symptoms had greatly improved after treatment compared with before treatment.Postoperative VAS score and Lund-Mackay score were lower than preoperative ones.Out of 87 patients,42 patients were successfully cured, 37 patients showed improvement, but there was no change in other 8 patients. The total efficacy rate was 90.81%.Conclusion:The combined treatment of recurrent allergic fungal rhinosinusitis treatment has achieved good effect. We should not only open sinus and remove the fungi, but also should pay attention to the elimination of inflammatory response in the treatment of recurrent allergic fungal rhinosinusitis.

[Clinical analysis of individualized nasal cavity ventilation expansion techniques for treatment of OSAHS patients]

Objective:To investigate efficacy of individualized nasal cavity ventilation expansion techniques for OSAHS patients with nasal obstruction. Method:One hundred and twelve OSAHS patients with nasal obstruction were included in this study. Nasal cavity ventilation expansion techniques were performed. Every patient took the examination of acoustic rhinometry, nasal respiration volume, rhinomanometry and polysomnography, and filled VAS of nasal obstruction and Epworth Sleep Scores(ESS) before surgery and three months after surgery. Result:Follow-up was for 6－12 months. Of all the patients, 39 cases were cured, 37 cases were remarkably improved, 21 cases were effective, and 15 cases were of no effect, respectively. Compared with pre-operative examination data in all OSAHS patients, nasal ventilation was markedly improved, the ESS was significantly decreased, the AHI was significantly decreased, LSaO2 and MSaO2 were significantly increased, and sleep structure did not change significantly in all OSAHS patients 6 month after nasal surgery. Conclusion:Individualized nasal cavity ventilation expansion techniques is an effective treatment for OSAHS patients with nasal obstruction，improves the safety of patients with UPPP surgery, and the tolerability of CPAP in some patients with ineffective surgery.

[CD23 on B cells determines Breg-facilitated IL-10 secretion as well as activation of T cells]

Objective:To explore whether or not the IL-10 mediated by Bregs modulate the secreting T cells activation by the anti-CD23 antibody, to find a new target for the treatment of allergic rhinitis. Method:The rat model of allergic rhinitis was established. Anti-CD23 antibody was used to observe the behavioral changes, passive skin allergen test, enzyme-linked immunosorbent assay, hematoxylin and eosin staining, immunofluorescence and flow cytometry serological indicators, systemic and nasal mucosa. Result:Compared with the blank control group, allergic rhinitis group rats sneezing, flexible nose, runny nose, subcutaneous mass increases;The levels of IL-10, IFN-γ and Bregs in blood decreased, the levels of IL-4, CD23+ B cells and CD4+ T cells increased;Nasal mucosa CD23 fluorescence intensity increased, CD19 and IL-10 fluorescence intensity decreased. Compared with the allergic rhinitis group, the number of sneezing, the frequency of nasal flexion, the symptoms of runny nose and the subcutaneous mass in the antibody intervention group were significantly improved;The levels of IL-10 in the blood, IFN-γ, the percentage of Bregs cells in whole blood increased, the levels of IL-4, CD23+ B cells and CD4+ T cells decreased;Nasal mucosa CD23 fluorescence intensity decreased, CD19 and IL-10 fluorescence intensity increased. There is little difference between the two routes of administration. Conclusion:The enhanced expression of CD23 on B cells is involved in the development of allergic rhinitis. The anti-CD23 antibody may control the symptoms and signs of allergic rhinitis. There is no significant difference between subcutaneous administration and improved nasal-drip way. As the preferred method of anti-CD23 antibody application, anti-CD23 is expected to become a new method to control and treat allergic rhinitis. Anti-CD23 antibodies can exert a therapeutic effect by T cell activation,which rely on the Bregs-mediated secretion of IL-10.

[Study of mumps immunity after administrating measles-mumps-rubella vaccine among children aged 2-7 years old in Jiangsu Province in 2015]

Objective: To investigate the immunity to mumps after administrating measles-mumps-rubella vaccine (MMR) among children aged 2-7 years old in Jiangsu province in 2015. Methods: A total of 4 190 healthy children aged 2-7 years old, living in local places for at least 3 months, and having been vaccinated at least 1 dose MMR were recruited to the study from Wujin district of Changzhou city, Gaogang district of Taizhou city and Ganyu district of Lianyungang city by using stratified cluster random sampling method between September and November, 2015. Those who did not accept MMR vaccination, who refused venous blood collection, who had affected mumps according to the memory of parents or teachers and who were diagnosed serious disease by clinical doctors were excluded from study. The self-designed questionnaire was used to collect the general information of the subjects and their MMR immunization history; and 0.5-2.0 ml of venous blood was collected from each subject. ELISA was used to detect the mumps antibody level in the serum of patients. Positive was defined as the antibody level ≥108 mU/ml, and negative as <108 mU/ml. χ(2) test was used to compare the difference in positive rates among subjects; and analysis of variance was used to compare the GMC changes in different time points after MMR vaccination. Results: Among 4 190 children, 2 280 were males (54.42%) and 1 910 were females(45.58%), and the positive rate of IgG antibody was 81.38% (3 344). There were 3 156 (95.18%) children vaccinated with one dose MMR, 187 (4.80%) children with two dose MMR, and 1 (0.02%) child with three dose MMR. The difference in positive rate of IgG antibody among different aged subjects showed statistical significance (χ(2)=58.61, P<0.001), the highest positive rate was in group of subjects aged 4-5 years old, at 89.43% (406/454), while the lowest positive rate was found among subjects aged 6-7 years old, at 75.63% (1 648/2 179). The positive rate after one dose of MMR vaccination was 79.14% (3 156/3 988), significantly less than it after two doses (93.03%, 187/201) (χ(2)=22.93, P<0.001). The GMC level at years<1, 1-<2, 2-<3, 3-<4, ≥4 following one dose MMR in the 3 988 children was 152.47, 227.78, 167.08, 126.91, 79.43 mU/ml, whose difference was statistically significant (F=51.29, P<0.001). Conclusion: The sero-prevalence of IgG antibody in the children aged 2-7 years old in Jiangsu province was high. The positive rate among who received two doses MMR was significantly higher than it among who received just one dose, and the GMC level waned with times.

Expression of prion protein in the cerebrospinal fluid of patients with Parkinson's disease complicated with rapid eye movement sleep behavior disorder

Parkinson's disease (PD) is one of the most common neurodegenerative diseases and mainly manifests with decreasing numbers of dopaminergic neurons. Rapid eye movement (REM) sleep behavior disorder (RBD) has an incidence of 15-47% in all PD patients. Prion proteins (PrPs), which are expressed in both neurons and glial cells of the brain, are believed to be correlated with abnormal neurological functions, although their role in PD-related sleeping disorders remains unclear. We therefore investigated the expressional profiles of PrP in PD patients with RBD. Quantitative real-time polymerase chain reaction and western blotting were used to detect the mRNA and protein levels of PrP, respectively, in the cerebrospinal fluid (CSF) of PD patients with RBD, PD patients without sleeping disorder, and healthy people (N = 23 each). We investigated the correlation between the CSF PrP level and sleeping behavior in PD patients. Patients with PD complicated with RBD had significantly elevated CSF PrP expression levels (both mRNA and protein) compared with either PD patients without sleeping disorder or healthy individuals (P < 0.05 in both cases). There is elevated expression of PrP in the CSF of PD patients with RBD. This may benefit the diagnosis of PD-related RBD.

Effects of stathmin 1 silencing by siRNA on sensitivity of esophageal cancer cells Eca-109 to paclitaxel

We investigated the effects of stathmin 1 (STMN1) silencing by small interfering (siRNA) on the sensitivity of esophageal cancer cells Eca-109 to paclitaxel. STMN1 siRNA was transiently transfected into Eca-109 cells. The effects of transfection were detected by quantitative polymerase chain reaction and western blotting. The effects of STMN1 silencing by siRNA on the sensitivity of esophageal cancer cells Eca-109 to paclitaxel was tested by MTT and colony formation assays. Hoechst 33258 nuclear staining was used to investigate the differences in Eca-109 cell apoptosis induced by paclitaxel. STMN1 siRNA was successfully transfected and the expression of STMN1 was inhibited. The sensitivity of STMN1 siRNA-transfected Eca-109 cells to paclitaxel was significantly increased (P < 0.01). The apoptosis of Eca-109 cells significantly increased following treatment with paclitaxel (P < 0.01). STMN1 silencing by siRNA may enhance the sensitivity of esophageal cancer cells Eca-109 to paclitaxel and induce apoptosis.

The small GTPase RhoA regulates the expression and function of the sodium channel Nav1.5 in breast cancer cells

Voltage-gated Na+ channels (VGSCs) are highly expressed in several types of carcinomas including breast, prostate and lung cancers as well as in mesothelioma and cervical cancers. Although the VGSCs activity is considered crucial for the potentiation of cancer cell migration and invasion, the mechanisms responsible for their functional expression and regulation in cancer cells remain unclear. In the present study, the role of the small GTPase RhoA in the regulation of expression and function of the Nav1.5 channel in the breast cancer cell lines MDA-MB 231 and MCF-7 was investigated. RhoA silencing significantly reduced both Nav1.5 channel expression and sodium current indicating that RhoA exerts a stimulatory effect on the synthesis of an active form of Nav1.5 channel in cancer cells. The inhibition of Nav1.5 expression dramatically reduced both cell invasion and proliferation. In addition, a decrease of RhoA protein levels induced by Nav1.5 silencing was observed. Altogether, these findings revealed: i) the key role of the small GTPase RhoA in upregulation of Nav1.5 channel expression and tumor aggressiveness, and ii) the existence of a positive feedback of Nav1.5 channels on RhoA protein levels.

γ-Aminobutyric acid-mediated neurotransmission in cerebellar-hypothalamic circuit attenuates gastric mucosal injury induced by ischemia-reperfusion

BACKGROUND

Excessive greater splanchnic nerve (GSN) activation contributes to the progression of gastric ischemia-reperfusion (GI-R) injury. This study was designed to investigate the protective mechanism of cerebellar fastigial nucleus (FN) stimulation against GI-R injury.

METHODS

The GI-R injury model was induced in rats by clamping the celiac artery for 30 min, and then reperfusion for 30 min, 1, 3, 6, or 24 h, respectively.

KEY RESULTS

Microinjection of L-Glu (3, 6, 12 μg) into the FN dose-dependently attenuated GI-R injury and GSN activity. In addition, there was an enhancement of gastric mucosal blood flow in GI-R rats. Pretreatment with the glutamic acid decarboxylase antagonist into the FN, the GABAA receptor antagonist into the lateral hypothalamic area or lesion of superior cerebellar peduncle all reversed the protective effects of the FN stimulation. Furthermore, the FN stimulation reduced the TUNEL-positive gastric mucosal cell and Bax-positive gastric mucosal cell in GI-R rats.

CONCLUSIONS & INFERENCES

These results indicate that the protective effects of the FN stimulation against GI-R injury may be mediated by attenuation of the excessive GSN activation, gastric mucosal cell apoptosis, and Bax expression in GI-R rats.

Recycling of waste tyre rubber into oil absorbent

The abundant and indiscriminant disposal of waste tyres has caused both health and environmental problems. In this work, we provide a new way to dispose off waste tyres by reusing the waste tyre rubber (WTR) for oil absorptive material production. To investigate this feasibility, a series of absorbents were prepared by graft copolymerization-blending method, using waste tyre rubber and 4-tert-butylstyrene (tBS) as monomers. Divinylbenzene (DVB) and benzoyl peroxide (BPO) were employed as crosslinker and initiator, respectively. The existence of graft-blends (WTR-g-tBS) was determined by FTIR spectrometry and verified using thin-layer chromatography (TLC). In addition, the thermal properties of WTR-g-tBS were confirmed by a thermogravimetric analyzer (TGA). Oil absorbency of the grafted-blends increased with increases in either feed ratio of WTR to tBS or DVB concentration. This absorbency reached a maximum of 24.0gg(-1) as the feed ratio and DVB concentration were 60/40 and 1wt%, respectively, after which it decreased. At other ratios and concentrations the absorbency decreased. The gel fraction of grafted-blends increased with increasing concentration of DVB. Oil-absorption processes in pure toluene and crude oil diluted with toluene were found to adhere to first-order absorption kinetics. Furthermore, the oil-absorption rate in diluted crude oil was observed to be lower than pure toluene.

[Pharmacokinetics and bioavailability of clinafloxacin in rats]

AIM

To study the pharmacokinetics and bioavailability of clinafloxacin in rats.

METHODS

The drug concentration was determined by HPLC. The main pharmacokinetic parameters were obtained by 3P87 program. An RP-C18 was used as the stationary phase. The mobile phase was a mixture of acetonitrile-0.05 mol.L-1 citric acid triethylamine (pH 2.5) (20:80). The flow rate was 1.0 mL.min-1. The UV absorbance detector was set at 300 nm.

RESULTS

A good linearity was obtained from 0.03-20 micrograms.mL-1 of clinafloxacin in rat plasma with gamma = 0.9998. The plasma concentration--time curve of clinafloxacin conformed to one compartment open model. After ig administration of 50 mg.kg-1 and 100 mg.kg-1 dose of clinafloxacin in six rats, mean Cmax and AUC values increased in proportion to dose. Mean T1/2 appeared to be independent of dose. Mean AUC was 65 +/- 6 and 27 +/- 4 micrograms.h.mL-1 respectively after i.v. and ig administration of 100 mg.kg-1 dose. The extent of bioavailability (F) of clinafloxacin was 42%.

CONCLUSION

The results of the pharmacokinetic study of clinafloxacin showed that it exhibited first order kinetic characteristics and the bioavailability is low.

RU486-induced growth inhibition of human endometrial cells

OBJECTIVE

To determine the direct action of RU486 on endometrial cell proliferation and to differentiate whether the antioxidant or the antiprogesterone property of RU486 is predominately responsible for its effect on cell growth.

DESIGN

In vitro study comparing the effects of RU486 (antiprogesterone and antioxidant), reduced RU486 (antioxidant), ZK112,993 (antiprogesterone), and lazaroid U74,500A (antioxidant) on endometrial cell growth. The human endometrial cell line EM42 was used in transient transfection assays to confirm the relative antiprogesterone potency of the various compounds.

SETTING

Academic medical center

PATIENT(S)

Women presenting with pelvic pain or infertility and diagnosed with endometriosis at time of surgery or women desiring tubal ligation with a normal pelvis (controls).

INTERVENTION(S)

Endometrial cell cultures were treated with RU486, reduced RU486, lazaroid U74,500A, and ZK112,993.

MAIN OUTCOME MEASURE(S)

Tritiated thymidine incorporation was used to assess cell growth. Inhibition of progesterone induction of transiently transfected reporter plasmids was used to measure antiprogesterone activity of compounds studied.

RESULT(S)

RU486 reduced cell growth in a dose-dependent fashion of the endometrial cell lines EM42 and RL95-2 and of endometrial and endometriosis cells from primary culture. After being reduced, RU486 lost most of its antiprogesterone activity but retained its antiproliferative properties. ZK112,993 was similar in potency to RU486 as a progesterone antagonist but did not significantly modify endometrial cell growth. Lazaroid U74,500A was devoid of antiprogesterone activity but was shown to be a potent antiproliferative agent.

CONCLUSION(S)

RU486 has a direct inhibitory effect on human endometrial cell growth. This activity appears to be at least partly mediated through its antioxidant property.

Helicobacter pylori associated with a high prevalence of duodenal ulcer disease and a low prevalence of gastric cancer in a developing nation

This study examines the relationship between Helicobacter pylori infection and peptic ulcer disease and gastric cancer--in particular, the presence or absence of bacteria, the grading of gastritis, and the degree of inflammation in the antral and oxyntic mucosae. The grading of gastritis and the detection of H pylori were determined by histology using the Sydney system. Of the 1006 patients examined, 34.5% had duodenal ulcer disease, 3.5% gastric ulcer disease, and 2% with coexistent ulceration. Most patients (50.2%) were classified as having non-ulcer dyspepsia. Altogether 2.4% of patients had gastric cancer and two further patients had carcinoma in the gastric stump. Of the ulcer disease patients, 87.2% had histological evidence of H pylori infection. After patients who had taken antibiotics or bismuth compounds in the preceding four weeks were excluded, 98.9% of the duodenal ulcer disease, 100% of the gastric ulcer disease, and 100% of the coexistent ulcer disease patients had evidence of H pylori infection. In patients with gastric cancer who had not taken antimicrobial agents in the four weeks before endoscopy, 83.3% had evidence of H pylori infection. Thus, there was a high rate of duodenal ulcer disease and a low rate of gastric ulcer disease in southern China, an area of low gastric cancer mortality. There was a specific topographical relationship between H pylori, the histological response, and gastroduodenal disease. Our data suggest that the status of a nation as either 'developed' or 'developing' can not be used to predict the upper gastrointestinal disease profile of its population.

Gastric heterotopia in the upper esophagus (inlet patch) in endoscopic surveys in northern China

Upper esophageal gastric heterotopia (inlet patch) has not been reported in endoscopic series from China. We describe the occurrence of endoscopically and histologically typical inlet patches in two endoscopic surveys of asymptomatic adults in northern China. Because rapid endoscopic protocols were used, the 0.3-0.4% prevalence of inlet patch in these surveys probably represents a minimum figure for adults in this population.

Identification of a 12.5-kD protein from caudate-putamen nucleus as a dopaminergic neuronotrophic factor

The effect of the extract from caudate-putamen nucleus of newborn rats (CPe) on the dopaminergic (DA) neurons has been studied. An MTT colorimetric microassay measuring optical densities for the growth of DA neuron cultures reveals a significant increase in growth for cultures with CPe as compared to those without CPe (p < 0.05). Rhodamine retrograde-prelabelled DA neurons were cultured on a Phastgel containing all the electrophoretically separated protein bands from CPe, and able to fish out from it their own trophic factor, a 12.5-kD protein band. The survived neurons at the 12.5-kD protein band were immunostained positive with anti-dopamine antibody. Co-culturing the 12.5 kD-containing gel strip with explants from substantia nigra at a close distance for a week revealed anti-dopamine immunopositive neurites outgrowing from the explants only towards the 12.5-kD gel strip. These results indicate that a 12.5-kD protein from the CPe is capable of maintaining the survival of DA neurons of the substantia nigra and promoting their neurite outgrowth.

Association of Helicobacter pylori with gastric cancer and observations on the detection of this bacterium in gastric cancer cases

OBJECTIVE

The aim of the present study was to assess the prevalence of Helicobacter pylori infection in Chinese patients with advanced gastric cancer, to compare this with a matched control population, and to identify factors that may effect the detection of H. pylori in patients with gastric cancer.

METHODS

Fifty-one patients with advanced gastric cancer and 102 age/sex-matched controls were included in the study. For the detection of H. pylori, both biopsy specimens and sera were collected from the patients, whereas only sera were collected from the controls. A strong association was shown between H. pylori and both intestinal and diffuse type gastric cancer. Antibiotic intake in the month before endoscopic examination, the site of collection of biopsy specimens, and tumor size were identified as factors that may reduce the histological detection of H. pylori in gastric cancer patients.

CONCLUSIONS

These data provide supporting evidence of an association between H. pylori infection and gastric cancer and indicate that, in certain circumstances, histological evaluation of H. pylori infection in gastric cancer cases may be less reliable than serological evaluation.

[Active constituents of Commelina communis L]

According to the pharmacological results five compounds were isolated from the herb of Commelina communis. Based on physico-chemical constants and spectral data, four of them were identified as n-triacontanol, p-hydroxycinnamic acid, daucosteril and D-mannitol. p-hydroxycinnamic acid shows antibacterial activity and D-mannitol shows antitussive effect.

[Growth inhibitory action of RGNTF-McAb on human retinoblastoma cell line Y-79]

The monoclonal antibody against the retinal ganglion neuronotrophic factor (RGNTF-McAb) was used in immunostaining of the Western blotting membrane separated from extract of human retinoblastoma cell line Y-79 to find that the latter contained a 30KD protein which was immunologically similar to the RGNTF secreted from the tectum of rat. The effect of different concentrations of RGNTF-McAb on the growth of Rb cells in cultures of different seeding concentrations was studied, revealing that the growth inhibitory action of RGNTF-McAb increased with increasing concentrations, up to 67% inhibition. Morphologically the growth and division of Rb cells were significantly inhibited as compared to the controls. The RGNTF-anti-idiotypic antibody was used for the localization of the RGNTF receptor, which the immunoreactive positive staining indicated to be on the surface of Rb cell membrane. The RGNTF-McAb could thus neutralize the RGNTF and inhibit growth of the Rb cells. These findings support the application of RGNTF-McAb to the treatment of retinoblastoma.

Changes in rat retinal ganglion neuronotrophic factor and its mRNA during postnatal development

The monoclonal antibody specific to the retinal ganglion neuronotrophic factor (RGNTF) was used to localize and quantify the presence and amount of RGNTF during the postnatal development of the visual system in the rat. The results showed that in the 0-1-day age group, neurons at the superficial layers and deep part of superior colliculus, and as well as retinal ganglion cells were strongly stained with their RGNTF contents quantified to be 88%, 100% and 100%, respectively. In the 5-6-day age group, RGNTF contents were significantly reduced to merely 50%, 30% and 80%, respectively. The RGNTF contents reduced further to 0% as age increased to 2 years old. A 32P-DNA probe specific to the first 7 amino acid sequence of RGNTF at its N-terminal end was synthesized and used for in situ hybridization studies. The results revealed that strong hybridized signals (i.e. mRNA of RGNTF) were localized in the same neurons in the superficial layers and deep part of the superior colliculus only in the 0-1-day age group, and that no signals were found in retinae of all postnatal age groups. The significant reduction of RGNTF may be related to the RGC death during postnatal development. Neurons at the superficial layers and deep part of the superior colliculus are the sources of RGNTF for RGCs in the postnatal retina.

[Immunotherapy of human retinoblastoma with RGNTF-monoclonal antibody using nude mice as model]

Retinoblastoma in nude mice as an animal model was developed by injecting cultured human retinoblastoma cell line(Rb) Y79 into the anterior chamber of eyeball. It was treated by direct injection of RGNTF-McAb into the Rb tumor. Ten out of 30 eyeballs with Rb inoculation did not develop tumor (32% inhibition) if Rb cell suspension was mixed with the RGNTF-McAb before injection; whereas in the control, all 40 but 3 eyeballs developed tumor (7%) when Rb cell suspension alone had been injected. This 32% of inhibition of Rb tumor formation by RGNTF-McAb was very significant (T > 2.58, P < 0.01). The results of immunotherapy of 46 eyeballs with Rb tumor developed 10 days after inoculation by RGNTF-McAb for 2 months revealed that the proportion of grade III-IV tumors before and after therapy reduced from 53% to 26% and that of grade I-II tumors increased from 47% to 74%. Feulgen DNA staining of tumor sections after therapy revealed that the average DNA contents in Rb cells decreased significantly (P < 0.01) from 16.2 +/- 2.6 in grade III-IV to 5.3 +/- 1.2 in grade I-II compared to that of the untreated control 18.8 +/- 3.2. Numerous white cells infiltrating the Rb tumor, hyperplasia of fibrous tissues, and no spreading and metastasis of the tumor tissue were observed in the treated eyeballs; whereas Rb tumor was spreading to the optic nerve and superior colliculus in the untreated eyeballs. Therefore, the RGNTF-McAb can not only inhibit the growth of Rb cells but also limit their spreading and metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxyntic and antral gastritis in the People's Republic of China: diagnosis and relationship to Helicobacter pylori

This study investigates the relationship between gastritis and Helicobacter pylori infection in the Chinese population. Particular focus was placed upon the grading of gastritis, using the recently developed "Sydney system." Five diagnostic procedures were used to establish H. pylori status, all of which were found to be highly sensitive and specific. Histological chronic gastritis was reported in 93/108 (86.1%) of the patients examined, H. pylori infection being present in 73/93 (78.5%), and in no patient with histologically normal mucosae. There was a relatively high incidence of idiopathic antral gastritis within the gastritic population, 20/93 (21.5%). In the H. pylori-positive group, 10/73 (13.7%) had pangastritis, 57/73 (78.1%) had pangastritis-antrum-predominant, and 6/73 (8.2%) had antral-only gastritis. The level of activity was significantly higher in the antrum; however, the distribution of bacteria between the antrum and body was not significantly different. There is a need for additional studies examining the specific topographical relationship between H. pylori, the histology, and gastroduodenal disease.

Nasopharyngeal and nasal malignant lymphoma: a clinicopathological study of 54 cases

Forty-one cases of nasopharyngeal and 13 cases of nasal malignant lymphoma have been examined histologically and immunohistochemically. All of the cases were non-Hodgkin's lymphoma; one case was of follicular type and the remaining 53 were of diffuse type. Large cell lymphoma comprised 48% of cases and most of the immunoblastic lymphomas showing pleomorphism occurred in the nose. Twenty-seven cases were of T-cell and 21 of B-cell phenotype. The predominance of T-cell lymphoma was due to an increased incidence of these in the nose, the T:B ratio of 3.33:1 contrasting with a 1:1.05 ratio in the nasopharynx. Nasopharyngeal lymphomas seem to show an intermediate incidence between the T-cell predominance in the nose and a B-cell predominance in the oropharynx. Since the large cell type of lymphoma was predominant, the differential diagnosis from undifferentiated carcinoma is important and is facilitated by the use of immunostaining methods.

[Immunohistochemical study of primary gastrointestinal malignant lymphoma]

63 cases of primary gastrointestinal non-Hodgkin's malignant lymphoma (ML), including 18 cases of gastric ML, 25 cases of small intestinal ML, 12 cases of ileocaecal ML and 8 cases of large intestinal ML, were studied. Small non-cleaved cell lymphomas were most common, accounting for 25.4% which was more common in the bowel than in the stomach. In 41 cases, a panel of monoclonal antibodies including L26, UCHL-1, Leu22 and Mac387 were used on paraffin section. The result of the staining was satisfactory in 37 cases. There were 35 cases (94.6%) exhibiting B-cell phenotype and 2 cases (5.4%) exhibiting T-cell phenotype. No histiocytic type was detected. The results of this and previous studies confirm the fact that most gastrointestinal lymphomas are B-cell lymphomas.

[Purification and survival of retinal ganglion cell]

We had used a specific anti-Thy 1.1 antibody binding method and a nylonmembrane sieve method to isolate and purify retinal ganglion cells from neonatal rats in order to compare the effect of tectal extract on these purified cells retinal ganglion cells. Isolated retinal cell suspension with retinal ganglion cells retrograde-prelabelled with Fast Blue were seeded on culture dishes coated with the specific anti-Thy 1.1 antibody for 30 minutes before nonadherent cells were removed. The percentage purity of the adherent retinal ganglion cells determined microscopically to be 95%. However, the percentage purity of the Fast Blue-labelled retinal ganglion cells recovered using the nylon membrane of pore size 15 microns was only 60 +/- 5%. Retinal ganglion cells purified by both methods could survive and grow into large, active neurons with neurite outgrowths in the presence of tectal extract. A MTT colorimetric microassay was used to quantify the survival growth activity of these purified retinal ganglion cells after culture for 24 hours. The result showed that the optical density ratio (+Te/-Te) of the retinal ganglion cells purified by anti-Thy 1.1 antibody binding method was 12.3 (0.111/0.009) and by the nylon membrane method was 6.4 (0.102/0.016), and the optical density ratio of the non-purified retinal cells was 3.8 (0.095/0.025), p less than 0.01 for all 3 sets of results. It was concluded that in the absence of other cells, the purified retinal ganglion cells responded specifically to the trophic activity in tectal extract, the purer the retinal ganglion cells and the clearer the effect.

Effect of a 30 kD protein from tectal extract of rat on cultured retinal neuron

For the first time we have shown here that the constituent from tectal extract (Te) which can support and promote the survival and growth of the retinal ganglion cell is a 30 kD protein. (i) Using MTT colorimetric microassay to measure the optical density for the survival and growth of the cultured retinal neuron, it was found that the optical densities for the experimental cultures with either Te, or its 10-30 kD fraction, or its greater than or equal to 30 kD fraction were 2-4 times that of the control culture without Te (P less than 0.01). This indicated that experimental cultures were more active in growth. (ii) The retinal neurons cultured on Te Phast gels showed that large retinal neurons (greater than 18 microns) grew only on the gel region containing the 30 kD protein. The retrograde prelabelled with horseradish peroxidase (HRP) for retinal ganglion cells indicated that these surviving neurons grown on Te Phast gel were HRP positive, i.e. retinal ganglion cells. (iii) The retinal explants cultured with 30 kD gels at a close distance of 1 mm apart revealed that many neurite outgrowths, up to 400 microns, extended from the retinal explants towards 30 kD gels, and that many individual cells and tissue masses migrated out from the explants and grew onto 30 kD gels. They were stained anti-neuron specific enolase and anti-Thy 1.1 positive, indicating they are retinal ganglion cells. Therefore, we concluded that the 30 kD protein is the neuronotrophic factor in the tectal extract specific for retinal ganglion cells.

[Inhibitory effect of interleukin-1 beta on follicle stimulating hormone (FSH) induced estrogen production by cultured rat granulosa cells]

Interleukin-1 beta (IL-1 beta), one of the polypeptide lymphokines released in response to antigen, toxins, injury or inflammation by nearly all cell types, has multiple systemic effects. In the present study the effect of IL-1 beta on follicle stimulating hormone (FSH)-induced estrogen production in primary culture was investigated. Granulosa cells obtained from immature estrogen-treated female rats were cultured for 3 days with increasing doses of FSH (1-30 ng/ml) with or without increasing doses of IL-1 beta (2-20 U/ml). The FSH stimulated estrogen production is dose-dependent, whereas IL-1 beta alone did not affect estrogen biosynthesis. In contrast, simultaneous treatment with IL-1 beta caused a dose-dependent inhibition of FSH action. This inhibitory effect of IL-1 beta was evident 48 h after the treatment. Furthermore, IL-1 beta inhibited forskolin (10(-5) mmol/L) and (Bu)2 cAMP (10(-2) mmol/L)-stimulated estrogen production, indicating a post-cyclic AMP site of action. The present study suggests that IL-1 beta is a potent modulator of granulosa cell steroidogenesis. Decreased estrogen formation may contribute to the follicle atresia and the impaired reproductive functions during injury and inflammation.

Gonadotroph adenomas in men produce biologically active follicle-stimulating hormone

Gonadotroph adenomas may exhibit qualitative and quantitative defects in gonadotropin biosynthesis and secretion. Hypersecretion of immunoreactive FSH dimers by these adenomas occurs frequently; however, it has not been known whether this FSH is biologically active. Using the granulosa cell aromatase bioassay and a highly specific immunoradiometric assay for FSH, we studied the serum bioactivity and bio- to immunoactivity (B/I) ratios of 14 men with FSH-secreting adenomas and compared these values to those of 11 age-matched normal men. In addition, three adenoma patients received TRH (400 micrograms, iv). The mean basal serum FSH level (international units per L), as measured by both bio- and immunoassays, and the FSH B/I ratios were significantly higher (P less than 0.02, by Kolmogorov-Smirnov test) in the adenoma patients than in normal men (mean +/- SEM; adenoma patients: bioactivity, 68.8 +/- 10.4; immunoreactivity, 34.8 +/- 13.7; B/I ratio, 3.4 +/- 0.6; normal men: bioactivity, 5.8 +/- 1.2; immunoreactivity, 6.4 +/- 0.8; B/I ratio, 0.90 +/- 0.1). Both bio- and immunoactive FSH rose after TRH injection, resulting in maintenance of the B/I (mean +/- SEM; pre-TRH: bio-FSH, 63.7 +/- 22.4; immuno-FSH, 28.0 +/- 14.1; B/I ratio, 2.8 +/- 1.2; post-TRH: bio-FSH, 125.6 +/- 42.7; immuno-FSH, 45.8 +/- 21.8; B/I ratio, 3.5 +/- 1.6). When gonadotroph adenoma cells from three separate patients were cultured and their conditioned media (n = 3) studied, relatively large amounts of both bio- and immuno-FSH were detected. Furthermore, the major isoelectric profile of bio-FSH (pH 4.9-3.0) in the conditioned medium from two such adenomas was shown by chromatofocusing to be comparable to that of purified human pituitary FSH (pH 5.2-3.6). We conclude that gonadotroph adenomas in men secrete FSH that is biologically active, both basally and in response to TRH.

Susceptibility of irradiated bovine aortic endothelial cells to injury

Using cultured bovine aortic endothelial cells (BAEC), the authors attempted to determine whether prior irradiation would alter the susceptibility of these cells to three known injurious stimuli and, if so, whether the alteration would be related to radiation dose. BAEC were irradiated with 0, 5, or 10 Gy of gamma rays and, on the third postirradiation day, exposed to fibrin, nicotine, or bacterial endotoxin (lipopolysaccharide, LPS). Release of prelabeled 51Cr, representing cell lysis, cell detachment, or a combination of the two, was determined. Significant differences between irradiated and control cells were determined by using paired Student's t-tests. Irradiation did not appear to have altered the sensitivity of BAEC to fibrin-induced injury. Cells irradiated with 10 Gy of gamma rays, but generally not those irradiated with half this dose, showed a heightened susceptibility to nicotine. Contrary to the nicotine results, irradiated cells showed less cell detachment and lysis after exposure to LPS. These results suggest that the susceptibility of irradiated BAEC to harmful stimuli depends largely on the nature of the stimulus as well as the radiation dose.

Cellular and extracellular plasminogen activator and inhibitor in an experimental tumour

We determined plasminogen activator (PA) and PA inhibitor (PAI) activities in the intra- and extracellular compartments of an experimental pancreatic ascites tumour with indirect and direct functional assays, and partially characterized these activities on SDS-polyacrylamide gels coupled with fibrin and reverse fibrin autography. Intact tumour cells caused lysis of plasminogen-rich but not plasminogen-free fibrin clots, and the extent of lysis of the former was related to tumour cell count. Direct assay of PA with a synthetic substrate yielded an equivalent of 109 urokinase units per 10(9) tumour cells. No PAI activity was demonstrated in tumour cells with functional assays. Contrary to tumour cells, cell-free ascitic fluids caused no lysis of fibrin clots. Instead, it inhibited tumour cell- and urokinase-induced, but not plasmin-induced, clot lysis in a dose-dependent fashion. Although functional assays failed to demonstrate PA in ascitic fluid and PAI in tumour cells, both activities were detected in electrophoresed samples of cell lysates and fluids by fibrin and reverse fibrin autography. In tumour cells, a mixture of tissue-type PA (tPA) and urokinase-type PA (uPA) were present. In the fluid, uPA together with two other PAs with greater molecular weights than tPA were detected.