[Correlation of endotracheal tube biofilm and recurrent ventilator-associated pneumonia with Pseudomonas aeruginosa]

OBJECTIVE

To determine the correlation of endotracheal tube biofilm (ETT-BF) and recurrent ventilator-associated pneumonia with Pseudomonas aeruginosa (PA-VAP) in long-term ventilation patients.

METHODS

Pulsed-field gel electrophoresis (PFGE) of Spe I enzyme-restricted chromosomal DNA was performed to identify the DNA patterns of Pseudomonas aeruginosa from ETT-BF, pharynx and lower respiratory tract secretion in 15 VAP patients. The chromosomal DNA fingerprint profile of each strain was compared with those from all other strains to calculate the similarity by using the correlation coefficient. The strains were then grouped and groups were depicted as a dendrite using the average clustering algorithm.

RESULTS

When bacteria has been isolated from ETT-BF, the same DNA pattern species are isolated from the lower respiratory tract secretion in 7 of 15 patients. Recurrent PA-VAP is caused by closely related and indistinguishable isolates in 6 of 15 patients. All PEGE patterns from 9 patients are different from one another (correlation coefficient < 31.2%).

CONCLUSIONS

The close pathogenic relationship between ETT-BF and lower airway secretion suggests that adhesive colonization of ETTs may be an important factor in the pathogenesis of VAP.

Ultrasonographic texture analysis of parenchymatous organs by the four-neighborhood-pixels algorithm: clinical experiment

OBJECTIVE

The parenchyma of organs such as liver, thyroid, and mammary gland during climacterium have common ultrasonographic textural features, which together form what we call small-dot-structure texture. To study this texture we designed the 4-neighborhood-pixels algorithm, an ultrasonographic texture analysis algorithm. The objective of this study was to confirm whether the 4-neighborhood-pixels algorithm can reflect the features of small-dot-structure texture.

METHODS

A changed small-dot-structure texture and 3 other textures were compared with the normal small-dot-structure texture in 4 groups, and a histogram algorithm was used for contrast with the 4-neighborhood-pixels algorithm.

RESULTS

The 4-neighborhood-pixels algorithm could reflect all the textural differences, but the histogram algorithm could reflect only some of them.

CONCLUSIONS

The 4-neighborhood-pixels algorithm is a good algorithm for analyzing ultrasonographic small-dot-structure texture. Not only can it reflect changes in the small-dot-structure texture, but it can also differentiate between small-dot-structure and non-small-dot-structure textures.

[Detection of aflatoxin-albumin adducts in human serum and its application]

Exposure to aflatoxin B1 (AFB1) is one of the major risk factors in the etiology of human hepatocellular carcinoma (HCC). The development of highly sensitive and specific methods for detecting AFB1 and its macromolecular biomarkers are critical for identifying individuals at risk for hepatocellular carcinoma. The detection of aflatoxin-albumin adducts (AFB-ALB) in serum has been used to investigate the relationship between aflatoxin exposure and HCC. A more sensitive and reliable method to detect AFB-ALB in serum was modified by separating serum albumin with Microcon-50 microconcentrators in stead of using precipitation. The method could separate serum albumin quickly and make protein digested in the same container. Thus, the step for transferring samples was reduced and recovery rate was improved. The AFB-ALB adducts were then determined by radioimmunoassay. The AFB-ALB adducts of human serum samples from Qidong, Jiangsu Province, and Fusui, Guangxi Zhuang Autonomous Region of the People's Republic of China were detected. The results indicated that the exposure of AFB1 is common and the positive rate for AFB-ALB adducts in serum of these populations is high.

[Experimental study on human pulmonary adenocarcinoma cell A549 transfected with HSV₁-TK gene in vitro and in vivo]

BACKGROUND

To observe killing effect of HSV₁-TK/GCV system on human pulmonary adenocarcinoma cell A549 in vitro and in vivo.

METHODS

A retroviral vector containing TK gene was constructed and transduced into pulmonary adenocarcinoma cell A549 by electroporation. The sensitivity of transfected cell to GCV in vitro and bystander effect and cellular apoptosis were observed. The recombination and expression of TK gene were examined by DNA PCR and in situ hybridization individually. In addition, the therapeutic effect of GCV on subcutaneous tumors inoculated with transfected and parental cells respectively was observed.

RESULTS

The transfected cells were irregular in shape, polyangular and easy of vacuolization. The double time of A549,A549-PLXSN and A549-TK was 36.15±3.27,40.82±3.75 and 42.06±4.12 hours respectively (P>0.05). The sensitivity of transfected cells to GCV was 46 times higher than that of parental cells and bystander effect was more apparent in high density inoculation cells than in low density. Apoptotic bodies and semimoon feature in nuclear were observed in transfected cells, but not in parental cell. Apoptotic cells were found significantly more in transfected cells than in parental cells by FCM and TUNEL (P<0.001). The recombination and expression of TK gene were positive in the transfected cells. In vivo, growth of tumors which formed by transfected cells was significantly inhibited by GCV, however, there was no similar inhibitive effect found in control group.

CONCLUSIONS

The transfected cells have obtained sensitivity to GCV. The killing effect of TK/GCV system on tumor cells is probably related to apoptosis. GCV could inhibit growth of tumors inoculated by transfected cells.

Changes and significance of circulating hepatocellular carcinoma cells in recurrent hepatocellular carcinoma patients after combined treatment

OBJECTIVE

To study the changes and significance of circulating hepatocellular carcinoma cells in recurrent hepatocellular carcinoma (HCC) patients after combined treatment of transarterial chemo-embolization(TACE) and percutaneous ethanol injection(PEI).

METHODS

We detected 19 blood samples from the recurrent HCC patients by nested RT-PCR to find out AFP mRNA before and after the treatment.

RESULTS

There were 7 patients with AFP mRNA positive before treatment (36.8%), and none of patients with AFP mRNA positive after treatment.

CONCLUSIONS

Combined treatment of TACE and PEI can effectively eliminate circulating hepatocellular carcinoma cells and thereby prevent metastasis and recurrence of HCC.

[Experimental study on suppressive effect of ginkgo extract on adhesion of vascular endothelial cell to monocyte induced by minimally modified low density lipoprotein]

OBJECTIVE

To observe the effect of Ginkgo extract on the interaction between minimally modified low density lipoprotein (MM-LDL) induced human umbilical vein endothelial cell (HUVEC) and U937 monocyte-like cell line.

METHODS

The adhesive percentage between HUVEC and U937 by counting and the expression of VCAM-1, ICAM-1, P-selectin by ELISA.

RESULTS

Treatment of HUVEC with MM-LDL (75 micrograms/ml) for 4 hrs could significantly increase the adhesion of U937 to HUVEC (P < 0.01) and Ginkgo extract could suppress the adhesion in dose-dependent manner. The surface expression of VCAM-1, ICAM-1, P-selectin was not induced by MM-LDL, while recombination tumor necrosis factor-alpha 5.0 ng/ml, as a positive control, could do.

CONCLUSION

Ginkgo extract afforded protection against HUVEC damage induced by MM-LDL and the adhesion of monocytes to endothelial cells induced by MM-LDL is not mediated by VCAM-1, ICAM-1 and P-selectin.

Changes in serum ammonia concentration in cirrhotic patients with Helicobacter pylori infection

OBJECTIVE

To study whether liver cirrhosis associated with Helicobacter pylori (H. pylori) infection will induce increased serum ammonia and whether the peripheral serum ammonia reflects the level of portal vein serum ammonia.

METHODS

Blood was taken from the portal vein and the cubital vein in cirrhotic patients with and without H. pylori infection and non-cirrhotic patients (splenic rupture) with and without H. pylori infection, and the serum ammonia was measured.

RESULTS

The mean levels of serum ammonia in the group of cirrhotic patients with H. pylori infection were 167.82 +/- 8.97 mumol/L (portal vein) and 142.2 +/- 13.35 mumol/L (cubital vein). They were increased significantly as compared with cirrhotic patients without H. pylori infection (47.68 +/- 12.03 mumol/L portal vein and 37.23 +/- 7.04 mumol/L cubital vein), and also compared with the groups of splenic rupture patients with and without H. pylori infection (P < 0.01). There was no significant difference between the serum ammonia level of the cubital vein and portal vein (P > 0.05).

CONCLUSIONS

H. pylori infection can induce an increase in serum ammonia in patients with liver dysfunction, and the peripheral serum ammonia measurement may replace the portal vein serum ammonia as a monitoring method. Eradication of H. pylori in cirrhotic patients may prevent hepatic encephalopathy (HE).

[Effect of hypoxia and carbon monoxide on rat pulmonary arterial smooth muscle cell]

OBJECTIVE

To investigate the effect of carbon monoxide on rat pulmonary arterial smooth muscle cell (VSMC).

METHODS

Three groups were randomly divided, (1) Normoxia group(N), (2) Hypoxia group(H), (3) 3% CO + 1% O2 group (CO + H), then tested by immunocytochemical analysis 3H-TdR in incorporation.

RESULTS

(1) Hypoxia initiated the chang of VSMC from contractile phenotype to synthetic phenotype, the endoplasmic reticulum became dilated, the mitochondria became swollen and myelin figure appeared. alpha-actin and muscle fiber decreased. The form of VSMC in CO + H was similar to that in N. (2) Intracellular Ca2+ level of VSMC in H [4 h, 8 h, 12 h, 24 h, 36 h were (382.00 +/- 37.92) mmol/L, (456.00 +/- 53.76) mmol/L, (517.00 +/- 47.34) mmol/L, (608.00 +/- 35.92) mmol/L, (567.00 +/- 46.72) mmol/L, respectively] increased significantly(P < 0.01) than in N[4 h was(319.00 +/- 47.45) mmol/L], but that in CO + H increased slightly. (3) cAMP and cGMP level of VSMC in H increased significantly, cAMP of VSMC in CO + H increased significantly [2 h, 8 h, 12 h, 24 h were (1.87 +/- 0.36) pmol/mg protein, (2.16 +/- 0.36) pmol/mg protein, (2.36 +/- 0.41) pmol/mg protein, (2.12 +/- 0.39) pmol/mg protein, respectively] but cGMP of VSMC in CO + H increased slightly[2 h, 8 h, 12 h, 24 h were (0.52 +/- 0.21) pmol/mg protein, (0.58 +/- 0.21) pmol/mg protein, (0.60 +/- 0.24) pmol/mg protein, (0.68 +/- 0.29) pmol/mg protein, respectively].

CONCLUSION

Hypoxia may promote the proliferation of VSMC by second messenger system and CO in low desities can depress the action of hypoxia partly by Ca(2+)-cGMP system or by the expression of E2F-1 gene.

[Malignant transformation of mouse embryonic fibroblast induced by mitochondrial DNA fragments]

OBJECTIVE

To investigate the malignant transforming effect and mechanism of mitochondrial DNA (mtDNA) fragments.

METHODS

Tumorigenicity of mtDNA-transformed mouse embryonic fibroblast (NIH3T3) in nude mice was studied using transgenic techniques. Transformed tumors were detected by pathological examination and hybridization signals of mtDNA probe were analyzed by fluorescence in situ hybridization (FISH) techniques.

RESULTS

Hybridization signals were observed on the nuclei of 18% - 20% NIH 3T3 cells 1 week after mtDNA fragments transforming. Tumor from mtDNA-transformed NIH 3T3 cells was developed in all 8 nude mice (8/8) respectively 2 weeks after the transformation. The pathological characteristics of the tumors developed were similar to that of fibrosarcoma.

CONCLUSIONS

Auto-integration of mtDNA fragments into nuclear genome is a new factor involved in carcinogenesis.

[Effects of dexamethasone on apoptosis and expression of Fas/FasL system in lung tissues of ALI rats]

OBJECTIVE

To determine whether apoptosis occurs in the lung tissues from rats with acute lung injury (ALI), and observe protective effects of dexamethasone by regulating apoptosis of lung tissues in rats with ALI.

METHODS

By using TUNEL, in situ hybridization, SqRT-PCR and immunocytochemistry techniques, apoptosis and Fas, FasL expression were studied during early phase of ALI in rats.

RESULTS

LPS leads to the rapid appearance of apoptosis in alveolar epithelial cells and pulmonary vascular endothelial cells at early stage of ALI in rats. The expression of Fas, FasL mRNA and protein was up-regulated in lung tissues of rats with ALI. The administration of dexamethasone suppressed apoptosis as well as expression of Fas, FasL mRNA and protein, inhibited TNF-alpha production and abated lung injury.

CONCLUSIONS

The excessive apoptosis and Fas/FasL system may play a role in the pathogenesis of LPS-induced ALI in rats. The protective effects of dexamethasone include inhibiting inflammatory mediators production, suppressing the activation of Fas/FasL system and apoptosis in lung tissues of ALI rats.

[The role of apoptosis and Fas/FasL in lung tissue in patients with acute respiratory distress syndrome]

OBJECTIVE

To evaluate the effects of apoptosis and expression of apoptotic related genes on acute respiratory distress syndrome (ARDS).

METHODS

Nine patients with ARDS and 5 non-ARDS patients were included. By using TUNEL, histopathology and immunocytochemistry techniques, apoptosis and Fas, FasL protein expression were studied in patients with ARDS in acute stage and in control subjects.

RESULTS

Apoptosis ratio was significantly higher in lung tissues in the patients with ARDS than in those of control subjects, especially in alveolar epithelial cells and pulmonary vascular endothelial cells. Fas, FasL protein expression were up-regulated in lung tissues of patients with ARDS. There was a significant correlation between expression of Fas, FasL and ratio of apoptosis.

CONCLUSIONS

During the acute stage of ARDS, increase of apoptosis ratio in alveolar epithelial cells and pulmonary vascular endothelial cells, and activation of Fas/FasL system may contribute to the pathogenesis of this syndrome.

[A preliminary study on the markers of pulmonary vascular endothelial cells in patients with ARDS]

OBJECTIVE

To explore the changes of the markers of pulmonary vascular endothelial cell (PVEC) in patients with ARDS.

METHODS

The levels of plasma circulating endothelial cell(CEC), granule membrane protein-140(GMP-140), endothelin-1(ET-1) and von Willebrand factor (vWF) were determined respectively in 13cases of ARDS. The vWF on the surface of the PVEC were stained in 5 cases of ARDS.

RESULTS

Circulating CEC, GMP-140, ET-1 and vWF levels were increased significantly (P < 0.01) but scores of vWF expression on the PVEC became weak (P < 0.01) in ARDS samples. The level of plasma GMP-140 elevated dramatically in 2nd day( > 4 times).

CONCLUSIONS

PVEC are severely impaired during ARDS. GMP-140 released from PVEC might be a satisfactory criteria for early surveillance and for evaluation of prognosis of ARDS in clinical practice.

Computing minimum description length for robust linear regression model selection

A minimum description length (MDL) and stochastic complexity approach for model selection in robust linear regression is studied in this paper. Computational aspects and implementation of this approach to practical problems are the focuses of the study. Particularly, we provide both algorithms and a package of S language programs for computing the stochastic complexity and proceeding with the associated model selection. A simulation study is then presented for illustration and comparing the MDL approach with the commonly used AIC and BIC methods. Finally, an application is given to a physiological study of triathlon athletes.

[Clinical application of expandable metal stent for palliation of malignant biliary obstruction]

OBJECTIVE

To investigated the long-term result of expandable metallic biliary stent implantation and evaluated preliminarily the factors that might impact the therapeutic effectiveness.

METHODS

134 patients with malignant choledochal stenosis were treated with metallic endo-prosthesis (128 transpapillary endoscopically and 6 transhepatic percutaneously). The follow-up results were compared with those of 97 patients with conventional plastic stents during the same period.

RESULTS

The success rate was 95.7%, and the procedure related complications were found in 6.4% of patients. The jaundice was eliminated completely in 85.6% patients. During long-term follow-up, the metal stents were shown patent for a mean duration of 300 days, which was significantly longer than 80 days of polyethylene endoprostheses (P < 0.01). The mean survival was 210 days. From classified data assessment, the stent patency in primary bile duct neoplasm group was almost similar to that in metastatic group, but the median survival of the former was slightly longer than that of the latter. There were flow differences in patancy and survival rates between the hilar obstruction group and the middle and low obstruction group.

CONCLUSIONS

The median patancy of expandable metal stents was significantly longer than that of conventional plastic prostheses. To get the highest benefit, however, the indication should be strictly selected.

[The role of ICAM-1 in leukocyte adherence to endothelial cells induced by hypoxia/reoxygenation]

OBJECTIVE

To determine whether intercellular adhesion molecule-1 (ICAM-1) mediats the polymorphonuclear leukocyte (PMN) adherence to endothelial cells elicited by hypoxia/reoxygenation (H/R).

METHODS

Human umbilical vein endothelial cells (HUVEC) monolayers was exposed to hypoxia for 30 min or 120 min then reoxygenated. Count the number of PMN in adhesion assays. Expression of ICAM-1 and ICAM-1 mRNA was detected by immunohistochemical analysis and in situ hybridization.

RESULTS

PMN adhesion to HUVEC exposed to H/R was significantly increased (1 fold) as compared with that of control (P < 0.01). H/R induced hyperadherence was significantly diminished by monoclonal antibodies directed at ICAM-1 or CD11a/CD18. The results showed an increased expression of ICAM-1 and ICAM-1 mRNA on HUVEC exposed to H/R. Hypoxic HUVEC might be responsible for PMN adesion.

CONCLUSIONS

ICAM-1 mediated the adhesive interaction between PMN and VEC induced by hypoxia/reoxygenation.

[Systemic inflammatory response syndrome in critical patients - an analysis of 1,292 cases]

OBJECTIVE

To study the significance of the occurrence and the development of systemic inflammatory response syndrome (SIRS) in critical patients.

METHODS

The clinical data of 1292 patients accepted by our hospital in ten months from October 1995 to July 1996 were analyzed. The patients met at least two of the criteria for SIRS such as fever, hypothermia, tachycardia, tachypnea or abnormal white blood cell count.

RESULTS

1292 (67.7%) of the 1909 patients investigated met two or more of the criteria for SIRS. In the 1292 cases, those who met two, three or four of the criteria were respectively 467 (36.1%), 526 (40.7%) and 299 (23.1%). 149 patients (11.5%) in the 1292 cases died of multiple organ dysfunction syndrome (MODS). In which 33 (7.1%), 57 (10.8%) and 59 (19.7%) respectively in patients with two, three and four of the criteria for SIRS. The proportion of patients suffering from acute respiratory distress syndrome, metabolic function dysfunction, disseminated intravascular coagulation and acute renal failure increased with the increase in the number of SIRS criteria that the patients met and with the increase in the proportion of patients progressing from SIRS to septic shock. The mortality rate of the patients also gradually increased while the patients with SIRS were developing sepsis, severe sepsis and septic shock, but there was no statistical significance (P > 0.05).

CONCLUSION

It is suggested that bacterial infection, severe trauma and acute pancreatitis might cause SIRS and compensatory anti-inflammatory response syndrome might play an important role in the maintenance of internal environment of the body. A comprehensive understanding of SIRS might be of help to the management of critical diseases.

[Changes of the deformability of neutrophil and the influence of anisodamine on neutrophil deformability during endotoxin-induced acute lung injury in rats]

OBJECTIVE

To explore the mechanisms of change of deformability of polymorphonuclear leukocytes (PMN) and influence of anisodamine on deformability of PMN during endotoxin-induced acute lung injury (ALI) in rat. To explore the role of PMN in ALI.

METHOD

The model of ALI in rat was reproduced by intravenous injection of E Coli endotoxin. The deformability of PMN was measured by micropipette aspiration technique.

RESULT

The elastic modulus K1 of PMN at the 1st hour (33 +/- 12 Pa), 4th hours (37 +/- 12 Pa, 1 Pa = 0.0075 mmHg) and 6th hours (38 +/- 13 Pa) after injection of E Coli endotoxin are all significantly higher than that in the control group (26 +/- 9 Pa P < 0.01). The viscosity modulus (mu) of PMN at the 4th hours (5 +/- 3 Pa.s) and 6th hours (6 +/- 3 Pa.s) after injection of E Coli endotoxin are all significantly higher than the control group (3.1 +/- 2.6 Pa.s, P < 0.01). The elastic shear modulus (G) of PMN at the 4th hours (54 +/- 20 Pa) and the 6th hours (56 +/- 21 Pa) after injection of E Coli endotoxin are all significantly higher than the control group (47 +/- 17 Pa, P < 0.05). The K1(33 +/- 12 Pa) and mu(4 +/- 3 Pa.s) in anisodamine group are all significantly lower than endotoxin group in the same time phases (P < 0.05).

CONCLUSION

The deformability of PMN decrease remarkably during ALI, which will enhance PMN sequestration in lungs, lead to ALI. It may be one of important pathogenic mechanism of ALI. The anisodamine can inhibit the decrease of deformability of PMN effectively and may have some therapeutic effect on ALI.

[The detection of circulating hepatocellular carcinoma cells in peripheral venous blood by reverse transcription-polymerase chain reaction and its clinical significance]

OBJECTIVE

To detect circulating hepatocellular carcinoma by demonstrating hepatocellular carcinoma cells-associated mRNA in the nuclear cell component of peripheral blood (PBL).

METHOD

Peripheral blood (5 ml) samples were obtained from 93 patients with hepatocellular carcinoma (HCC) and from 37 controls (15 controls with liver cirrhosis after hepatitis B, 12 chronic hepatitis B, and 10 normal liver function). To identify HCC cells in peripheral blood, liver-specific human alpha-fetoprotein (AFP) mRNA was amplified from total RNA extracted from whole blood by reverse transcription-polymerase chain reaction.

RESULT

AFP mRNA was detected in 50 blood samples from the patients with HCC (53.8%). In contrast, there were no clinical control patients whose samples showed detectable AFP mRNA in PBL. The presence of AFP mRNA in blood seemed to be correlated with the stage (by TNM classification) of HCC, the serum AFP value, and the presence of intrahepatic metastasis, portal vein thrombosis, tumor diameter and/or distant metastasis. AFP mRNA was detected in the blood of 21 patients showing metastasis at extrahepatic organs (100%) in contrast to 29 of 72 patients without metastasis (40.3%).

CONCLUSION

The presence of AFP mRNA in peripheral blood may be an indicator of malignant hepatocytes, which might predict hematogenous spreading metastasis of tumor cells in patients with HCC.

Expression of splice variants of CD44 mRNA and its significance in human primary hepatocellular carcinoma

OBJECTIVE

To investigate the relationship between the expression of splice variants of CD44 (CD44v) and the metastasis of primary hepatocellular carcinoma (PHCC) in humans.

METHODS

The expression of metastasis-associated CD44v mRNA in 54 specimens of human PHCC was detected by reverse transcription and polymerase chain reaction (RT-PCR) method.

RESULTS

CD44v mRNA was expressed in 50 (92.59%) of the 54 specimens of PHCC, with moderate or over expression in 42 (77.78%). Among the 42 specimens with moderate or over expression, deficient tumor capsules were found in 25 (59.52%), penetration of tumor capsule in 15 (35.71%), tumor emboli in the portal vein in 34 (80.95%), and daughter tumor nodules in 29 (69.05%). Meanwhile, 12 of the 54 specimens showed negative or weak expression of CD44v mRNA. Of them, all had tumor capsules, 1 (8.33%) had penetrated tumor capsule, 1 (8.33%) had tumor emboli in the portal vein, and 2 (16.67%) had daughter tumor nodules.

CONCLUSION

CD44v may contribute to the metastatic potential of PHCC.