[Studies on properties of biofriction and wear for friction pairs of UHMWPE and Ti matrix-TiN-TiC gradient film materials]

In order to search the possible application of friction pairs of UHMWPE and Ti6Al4V-TiN-TiC etc. gradient materials to total hip joint replacements, we have prepared Ti6Al4V-TiN-TiC etc. gradient film materials by using N ion implant, d. c plasma CVD(PCVD). The properties of biological friction and wear for friction pairs of HUMWPE and Ti6Al4V-TiN-TiC etc. gradient film materials were investigated. The friction coefficient of friction paris and the wear loss of worn UHMWPE were measured; the surface morphology was observed by SEM. It has been shown that in human serum lubrication the wear loss of HUMWPE decreases with the increase in the surface hardness of its pairing ceramic film material. The pairing Ti6Al4V-TiN-TiC gradient film material possesses highest surface hardness, compared with other materials studied; UHMWPE wear loss in lowest. The wear mechanism of studied pairs has been analysed as well in the present paper.

[3-D direct matching interpolation for rotary scanning echo-cardial images]

In the present paper, a method of three dimension direct matching interpolation for a series of 2-D echo-cardial images with intersecting each other and arranging at an angle in space has been developed. It is different from the conventional interpolation. During the interpolation, sectional images are acquired and the 3-D spatial position of "empty voxel" in sectional images is located; secondly, the cubic volume is constructed, and the motion orbit of images between two windows where the nearest original image intersects to the volume is found up, passing through the "empty voxel"; In the end, based on the matching pixels, the "empty voxel" is interpolated. This method simplifies the two interopolating procedures of the conventional methods into one procedure, and overcomes the shortcoming of the overlap of image data. Experiments show that the accuracy and reasonability of interpolation can be improved by the proposed method.

Congenital choledochal cyst--report of 56 cases

OBJECTIVE

The aim of this paper is to describe the mechanism, clinical manifestation, diagnosis and surgical management of congenital choledochal cyst.

METHODS

From 1984 to 1997, 56 cases of congenital choledochal cyst were reviewed. Among them, 8 patients were male, 48 patients were female, the age ranges from 12 to 50 years old with an average of 26.3.

RESULTS

The main clinical manifestation includes jaundice, abdominal pain and abdominal mass. All of them were confirmed by ultrasonography, while 39 cases were performed ERCP and PTC with the same diagnosis. Fifty-one patients were performed cystectomy and hepatojejunostomy, two cases were performed cystjejunostomy because of diffused angioma and severe hemorrhage respectively, external drainage was performed in one case with emergent cholangitis, the other two cases were reported malignancy through biopsy and operation was abandoned.

CONCLUSIONS

Ultrasound diagnostics is essential to accurately diagnose the cyst, preoperative ERCP is helpful for differentiating pancreatic duct from bile duct, while MRCP is a reliable method; cystectomy and cholangiojejunostomy is recommended, laparoscopic procedure is becoming more and more accepted.

[The development of an extracting method for high frequency components of abnormal intra-QRS of exercise ECG signal]

This article introduces a method of extracting high frequency components of abnormal intra-QRS of exercise ECG signal by using spline function interpolation algorithm, and defines QRSe of the residual signal as quantitative index. Some expected results have been obtained. This method is an effective measuring approach to further researches on the high frequency components of exercise and other ECG signals.

[Prevention and management of complications with laparoscopy cholecystectomy]

OBJECTIVE

To prevent the complication of laparoscopy cholecystectomy (LC).

METHODS

This text analysed 1,200 cases retrospectively with LC from Feb. 1993 to May. 1998.

RESULTS

Three cases with biliferous duct injury, two cases with bile leakage from the stamp of cystic duct, two cases with gallbladder artery injury.

CONCLUSIONS

Strict preoperative examination and standard operative procedure can reduce markedly complication of LC.

Genomic integration and gene expression by a modified adenoviral vector

A replication-deficient recombinant adenovirus encoding luciferase was constructed using 5' and 3' long terminal repeat (LTR) sequences of the Moloney murine leukemia virus. Gene expression was observed in cultured cells in vitro and in submandibular gland, cortex, and caudate nucleus for as long as three months in vivo. The vector integrated randomly into the genome of both dividing and nondividing cells as determined by fluorescence in situ hybridization (FISH) (10-15% of cells in vitro and 5% in rat spleen in vivo), gene walking, Southern hybridization, and polymerase chain reaction (PCR), in the absence of transcomplementing reverse transcriptase or integrase activity. The new vector combines the high titer and versatility of adenoviral vectors with the long-term gene expression and integration of retroviral vectors.

Effect of intranasal treatment with capsaicin on the recurrence of polyps after polypectomy and ethmoidectomy

The aim of this study was to evaluate the influence of five intranasal applications of capsaicin, performed after endoscopic polypectomy associated with partial middle turbinectomy and anterior ethmoidectomy, on the recurrence of nasal polyps and the intensity of nasal obstruction and rhinorrhea. Fifty-one patients (19 females, 32 males, mean age 43 years) suffering from nasal polyposis for more than 1 year were included in this double blind, randomized, placebo-controlled study. During post-surgical controls, local anaesthesia and vasoconstriction of the middle meatus area were performed in all patients with a cotton pellet soaked with lidocain and adrenaline. In 29 patients, the same type of cotton pellet soaked with capsaicin (3 x 10(-6) mol. dissolved in 70% ethanol) was left into the middle meatus of both nostrils for 20 min. As a control group, 22 patients, matched for age and sex, were treated with the capsaicin vehicle alone (70% ethanol). All patients studied received the intranasal treatment once a week for 5 weeks. Subjective evaluations of nasal airway resistance (NAR) and rhinorrhea were recorded by means of a visual analogue scale. Clinical staging of the nasal polyposis (graded from stage 0 = absence of polyp to stage 3 = polyps occupying the entire nasal cavity) was evaluated by the same ENT specialist (ZW) using a 0 degrees endoscope. All parameters were recorded for each patient 1 week before surgery, then once a month for 9 months. Patients treated by endoscopic surgery followed by intranasal capsaicin application, reported a marked reduction in their NAR compared with the pretreatment evaluation (p<0.001). In contrast, patients treated with the vehicle alone did not have any significant improvement of their subjective NAR. Subjective rhinorrhea was not modified by either treatment. Patients treated with capsaicin showed a significant smaller staging of their nasal polyposis compared with the control group (p<0.001). These observations suggest that endoscopic surgery followed by intranasal capsaicin application reduces polyps and nasal obstruction recurrence and could be an alternative treatment to expensive corticosteroids in developing countries.

Adenoviral transfer of xenogeneic MHC class I gene results in loss of tumorigenicity and inhibition of tumor growth

The immune system confers protection against a variety of pathogens and contributes to the destruction of neoplastic cells. Foreign major histocompatibility complex (MHC) protein serves as a potent stimulus to the immune system. In this report, a mouse H-2Kb gene was introduced into two poorly immunogenic tumor cell lines, a mouse colonic carcinoma cell line, MCA-26 (H-2Kd), and a rat mammalian carcinoma cell line, LN-4, in an effort to stimulate tumor rejection. Our results showed that the expression of xenogeneic MHC class I antigen completely abolished the LN-4 tumorigenicity in rats, whereas the expression of allogeneic MHC class I antigen only partially reduced the MCA-26 tumorigenicity in mice. Rats with tumor regression of LN-4/H-2Kb developed a T helper type 1-dominant response, whereas rats with LN-4 tumor growth developed a T helper type 2-dominant response. The immunized rats that experienced LN-4/H-2Kb tumor regression further developed protective immunity against a subsequent challenge of LN-4 cells. This protective immunity was mediated by the LN-4 tumor-specific cellular immune response against both the transduced and the parental LN-4 cells. Recombinant adenoviral vectors are highly efficient at in vitro and in vivo gene delivery. The LN4 cells transfected with the recombinant adenovirus AdV-H-2Kb in vitro expressed the cell surface H-2Kb molecule by fluorescence-activated cell sorter analysis. Adenovirus-mediated H-2Kb gene transfer in vivo can further significantly inhibit pre-established LN-4 tumors. Those rats with complete tumor regression further developed protective immunity against the subsequent challenge of a parental LN-4 tumor. Therefore, our study indicates that the adenovirus-mediated transfer of xenogeneic MHC class I gene may be an effective alternative to the current protocol of cancer gene therapy in which the allogeneic MHC class I gene is used.

[Research on stochastic factors of heart rhythm variability in nonlinear dynamic analysis]

In this study, the influence of external noise on heart rhythm variability (HRV) in nonlinear dynamic analysis and the internal stochastic factor of HRV were discussed in connection with their physiological significance. The sampling rate, stationary and non-uniformity time interval were analyzed. An interpolation algorithm for heart period was introduced. The experiment demonstrated that the influence was highly reduced by the mentioned procedure. The internal stochastic factors of HRV were investigated by several nonlinear dynamic methods such as surrogate data, mutual information and nonlinear forecasting. The results suggested the colligation of deterministic chaos and stochastic process should be a favorite to interpret HRV.

Polymorphisms at - 174 and in the 3' flanking region of interleukin-6 (IL-6) gene in patients with myasthenia gravis

We examined the bi-allelic polymorphism at - 174 in the promoter region and the polymorphism in the 3' flanking AT rich region of the interleukin-6 (IL-6) gene in Swedish patients with myasthenia gravis (MG) and ethnically matched healthy individuals. There was no association between the polymorphisms and the disease. There was no relation of the polymorphisms to the clinical variables, the thymic histopathologies, the level of serum acetylcholine receptor antibodies or the concentrations of IgG and its subclasses. Our data yield no evidence for the IL-6 gene contributing to the disease susceptibility.

The JNKK2-JNK1 fusion protein acts as a constitutively active c-Jun kinase that stimulates c-Jun transcription activity

c-Jun N-terminal protein kinase (JNK), a member of the mitogen-activated protein (MAP) kinase family, regulates gene expression in response to various extracellular stimuli. JNK is activated by JNK-activating kinase (JNKK1 and JNKK2), a subfamily of the dual specificity MAP kinase kinase (MEK) family, through phosphorylation on threonine (Thr) 183 and tyrosine (Tyr) 185 residues. The physiological functions of the JNK pathway, however, are not completely understood. A major obstacle is the lack of specific and activated kinase components that can stimulate the JNK pathway in the absence of any stimulus. Here we show that fusion of JNK1 to its upstream activator JNKK2 resulted in its constitutive activation. In HeLa cells, the JNKK2-JNK1 fusion protein showed significant JNK activity, which was comparable with that of JNK1 activated by many stimuli and activators, including EGF, TNF-alpha, anisomycin, UV irradiation, MEKK1, and small GTP binding proteins Rac1 and Cdc42Hs. Immunoblotting analysis indicated that JNK1 was phosphorylated by JNKK2 in the fusion protein on both Thr(183) and Tyr(185) residues. Like JNKK2, the JNKK2-JNK1 fusion protein was highly specific for the JNK pathway and did not activate either p38 or ERK2. Transient transfection assays demonstrated that the JNKK2-JNK1 fusion protein was sufficient to stimulate c-Jun transcriptional activity in the absence of any stimulus. Immunofluorescence analysis revealed that the JNKK2-JNK1 fusion protein was predominantly located in the nucleus of transfected HeLa cells. These results indicate that the JNKK2-JNK1 fusion protein is a constitutively active Jun kinase, which will facilitate the investigation of the physiological roles of the JNK pathway.

[The method of wavelet transformation used for extracting the characteristic of the exercise ECG]

This article introduces the basic rationale of wavelet transformation and the algorithm of typical dyadic wavelet transformation with mother wavelet of the first derivative of a Gaussian smoothing function, this wavelet transformation is used to recognize the characteristic parameters of the exercise ECG, it is concluded that this method make significant effects on restricting base line drifting and lessening noisy component in the exercise ECG, it provides a new way to do further research on characteristic recognition of the exercise ECG in the exercise test.

[Vroman effect of plasma protein adsorption to biomaterials surfaces]

Fibrinogen adsorption from plasma to biomaterials surfaces passes through a maximum when studied as a function of adsorption time, plasma concentration, or column height in narrow spaces and these are called Vroman effect. Studies have demonstrated that Vroman effect is a general phenomenon of plasma proteins and reflects the competitive adsorption of plasma proteins for a limited number of surface sites. In this paper, the factors affecting Vroman effect, the relationship between contact activation and fibrinogen displacement, and the significance of the Vroman effect with respect to blood-material interactions are reviewed.

Natural attenuation of BTEX compounds: model development and field-scale application

Benzene, toluene, ethyl benzene and xylene (BTEX) dissolved into ground water and migrated from a light nonaqueous phase liquid (LNAPL) source in a sandy aquifer near a petroleum, oil, and lubricants (POL) facility at Hill Air Force Base (AFB), Utah. Field observations indicated that microbially mediated BTEX degradation using multiple terminal electron-accepting processes including aerobic respiration, denitrification, Fe(III) reduction, sulfate reduction, and methanogenesis has occurred in the aquifer. To study the transport and transformation of dissolved BTEX compounds under natural conditions, a reactive flow and transport model incorporating biochemical multispecies interactions and BTEX was developed. The BTEX, oxygen, nitrate, Fe(II), sulfate, and methane plumes calculated by the model agree reasonably well with field observations. The first-order biodegradation rate constants, estimated based on model calibration are 0.051, 0.031, 0.005, 0.004, and 0.002 day(-1) for aerobic respiration, denitrification, Fe(III), sulfate reduction, and methanogenesis, respectively. The results of a sensitivity analysis show that the saturated aquifer thickness, hydraulic conductivity, and reaction rate constants are the most critical parameters controlling the natural attenuation of BTEX at this site. The hydraulic conductivity and aquifer thickness were found to be the key factors affecting the restoration of oxygen, nitrate, and sulfate after their interaction with the BTEX plume. The multispecies reactive transport modeling effort, describing BTEX degradation mediated by multiple electron-accepting processes, represents one of the few attempts to date to quantify a complete sequence of natural attenuation processes with a detailed field data set. Because the case study is representative of many petroleum-product contaminated sites, the results and insights obtained from this study are of general interest and relevance to other fuel-hydrocarbon natural attenuation sites.

[Multiresolution analysis based denoising algorithm for dynamic esophageal pH monitoring signal]

A denoising algorithm for dynamic esophageal pH monitoring signal is first introduced in this paper. The algorithm was developed on the basis of multiresolution analysis. The pH monitoring signal was investigated in experiments, then the algorithm was formulated by multiresolution analysis based on discrete dyadic wavelet transform combining with the results of the investigation mentioned above. Application of this algorithm to clinical data processing has proved its satisfactory denoising effect.

[Surgical treatment of gastric cancer in stage T1/T2: an reevaluation of the clinical significance of early gastric cancer]

OBJECTIVE

To evaluate the clinical significance of early gastric cancer by means of an analysis of the results of surgical treatment of gastric cancer in stage T1/T2.

METHODS

A retrospective review and survival analysis of 132 patients with stage T1/T2 stomach cancer treated from 1983 through 1993 was performed.

RESULTS

The average tumor size, lymph node involvement, postoperative recurrence and survival rate were significantly different between gastric cancer in stage T1 and T2. It was true of both groups of patients that the survival rate of patients with and without lymph node involvement was significantly different. However, the survival rate of patients in stage T2 but without lymph node involvement was not significantly different as compared to that of patients in stage T1.

CONCLUSION

For stage T1 stomach cancer, because of possible lymph node involvemnt, local mucosal excision of tumor is not recommended. For stage T2 stomach cancer without lymph node metastasis, it can be regarded as cancer still in its early stage when postoperative adjunct therapy is to be given.

[Endoscopic treatment of sphenoidal and ethmoidal mucoceles]

OBJECTIVE

To evaluate endoscopic surgery for sphenoidal and ethmoidal mucoceles.

METHOD

Seventeen patients diagnosed as having paranasal sinus mucoceles underwent attempted endoscopic marsupialization between 1989 and 1995. Ten of the mucoceles were in the sphenoid sinus, seven in the ethmoid sinus. Postoperative endoscopic follow-up period varied from 3 to 9 years.

RESULT

All the sphenoidal and ethmoidal mucoceles were satisfactorily approached endoscopically. Postoperative endoscopic examination manifested all the operating cavity was satisfactorily marsupialized. The symptoms were improved or relieved in 15 patients. None of the patients undergoing endoscopic surgery had significant complications.

CONCLUSION

Our results show that endoscopic surgery seems to be a safe, valuable way for management of sphenoidal and ethmoidal mucoceles.

[Usefulness of CYFRA21-1 as a tumor marker of non-small-cell lung cancer]

OBJECTIVE

To evaluate the clinical usefulness of CYFRA21-1 as a serum tumor marker in diagnosis, evaluation of clinical status and prognosis of patients with non-small-cell lung cancer (NSCLC).

METHODS

CYFRA21-1 in 126 serum samples of NSCLC patients was measured by radioimmunoassay. Of the 126 samples, 71 were collected before treatment, 29 at two weeks after operation, and 26 after 15-18 months follow-up.

RESULTS

CYFRA21-1 was positive in 49.3% of the NSCLC patients who had not received any treatment. The positive rate was 69.2% for squamous-cell carcinoma, and 25.0% for adenocarcinoma. The serum level of CYFRA21-1 was significantly higher in squamous-cell carcinoma than in adenocarcinoma (P < 0.0001). The serum level of CYFRA21-1 well correlated and increased with TNM staging (P = 0.0001). The level decreased significantly within two weeks after surgical operation in 29 cases (P = 0.0005). On follow up for 15-18 months, no change in CYFRA21-1 level was observed in 16 patients whose disease was stable, while there was significant increase in 10 patients with progressive disease.

CONCLUSION

CYFRA21-1 is a soluble fragment of cytokeratin 19 in serum of patients with NSCLC. It can be used as a useful tumor marker of NSCLC.

[The basic study of noninvasive detecting the ischemic/hypoxic cerebral injury]

The cerebrovacular diseases are important causes of mortality and disability in the world, and with the development of science and technology, many mission-oriented basic researches are aimed at the ischemic/hypoxic brain injury. This paper introduces some progress made in our research in this field, which includes: the animal experiment model of brain injury; the technique to efficiently extract evoked potentials from electroencephalogram; and the identification of the characteristic information of brain injury.

Effect of clodronate on macrophage depletion and adenoviral-mediated transgene expression in salivary glands

Expression of transgenes from adenoviral vectors is short-lived in salivary glands, in part because of immune responses to the virus and/or transgene product. Previous studies demonstrated that depletion of macrophages with multilamellar liposomes containing clodronate (Cl2MBP) increases adenoviral-mediated transgene expression in the liver. This technique was tested in salivary glands. Rats were treated with Cl2MBP-liposomes or control liposomes by femoral vein, intraperitoneal, or carotid artery injections. Thereafter, a recombinant adenovirus, AdCMVluciferase, was instilled intraductally in submandibular glands (SMGs), or delivered to the liver via femoral vein injection. Marked depletion (>94%) of liver macrophages and increased levels of luciferase activity in the liver (45-fold higher than controls) were present in animals receiving Cl2MBP-liposomes. In contrast, the same treatment never depleted more than 41% of SMG macrophages nor increased luciferase activity in SMGs, regardless of the route of administration. In conclusion, while macrophage depletion with Cl2MBP-liposomes is associated with markedly increased adenoviral-mediated transgene expression, this strategy was ineffective for salivary glands.

Structural basis of neurophysin hormone specificity: Geometry, polarity, and polarizability in aromatic ring interactions

The structural origins of the specificity of the neurophysin hormone-binding site for an aromatic residue in peptide position 2 were explored by analyzing the binding of a series of peptides in the context of the crystal structure of liganded neurophysin. A new modeling method for describing the van der Waals surface of binding sites assisted in the analysis. Particular attention was paid to the unusually large (5 kcal/mol) difference in binding free energy between Phe and Leu in position 2, a value representing more than three times the maximum expected based on hydrophobicity alone, and additionally remarkable since modeling indicated that the Leu side chain was readily accommodated by the binding pocket. Although evidence was obtained of a weak thermodynamic linkage between the binding interactions of the residue 2 side chain and of the peptide alpha-amino group, two factors are considered central. (1) The bound Leu side chain can establish only one-third of the van der Waals contacts available to a Phe side chain. (2) The bound Phe side chain appears to be additionally stabilized relative to Leu by more favorable dipole and induced dipole interactions with nonaromatic polar and sulfur ligands in the binding pocket, as evidenced by examination of its interactions in the pocket, analysis of the detailed energetics of transfer of Phe and Leu side chains from water to other phases, and comparison with thermodynamic and structural data for the binding of residue 1 side chains in this system. While such polar interactions of aromatic rings have been previously observed, the present results suggest their potential for significant thermodynamic contributions to protein structure and ligand recognition.

Identification of T-DNA tagged Arabidopsis mutants that are resistant to transformation by Agrobacterium

We have identified T-DNA tagged Arabidopsis mutants that are resistant to transformation by Agrobacterium tumefaciens (rat mutants). These mutants are highly recalcitrant to the induction of both crown gall tumors and phosphinothricin-resistant calli. The results of transient GUS (beta-glucuronidase) assays suggest that some of these mutants are blocked at an early step in the Agrobacterium-mediated transformation process, whereas others are blocked at a step subsequent to translocation of T-DNA into the nucleus. Attachment of Agrobacterium to roots of the mutants rat1 and rat3 was decreased under various incubation conditions. In most mutants, the transformation-deficient phenotype co-segregated with the kanamycin resistance encoded by the mutagenizing T-DNA. In crosses with susceptible wild-type plants, the resistance phenotype of many of these mutants segregated either as a semi-dominant or dominant trait.

[Using complexity measurement to study the EEG signal of focal ischemic cerebral injury]

In this paper, a model for SD rat focal ischemic cerebral injury is presented. Based on this experiment model, we recorded the EEG of ischemic region and normal region from before ischemia to after ischemia 30 minutes. We analyzed the complexity of these EEG signals, and found that the EEG complexity was very sensitive to focal ischemic cerebral injury. The EEG complexity on ischemic region was less than that on normal region. The difference in EEG complexity between two regions increased with the decreasing velocity. When insult took place, the EEG complexity was less than that before ischemai. These resluts agree to those we obtained by Discrete Gabor Spectrogram analysis and Heat Shock Protein (HSP) expression. The ischemic and normal regions can be clearly distinguished by analyzing their EEG complexity, and the extent can also be detected in this way.

[The characteristic wave intervals of exercise ECG influenced by changing of heart rate]

This paper analyzes the characteristic wave intervals of exercise ECG influenced by heart rate changing under exercise test. The most influenced parameter is TP interval, the next is QT interval, and the width of P wave and QRS waves are nearly unchanging. According to the changing characteristic of these waves width mentioned above, we suggest an adaptive adjusting method for ST segment measuring position after the J point, which is of significance to recognizing the characteristic waves and determining the result of exercise test for myocardial ischemia.