2000年 · 第113卷第06期

Objective To illustrate the automatic modulation of refractoriness of His-Purkinje system during atrioventricular nodal reentrant tachycardia (AVNRT) and to discuss the possible mechanisms. Methods Programmed electrical stimulations were performed in high right atrium (HRA) in 8 patients with AVNRT before ablation to induce tachycardia and electrocardiagraphic recordings were done synchronically when AVNRT appeared. Results All the patients had 2 : 1 atrioventricular (A-V) conduction when AVNRT began, 2 of whom were blocked below His bundle, 5 above His bundle and 1 unclear. After a duration of 14.03 ± 10.03 s of 2:1 A-V conduction, 1 : 1 A-V conduction with bundle banch block appeared, 3 of which were right bundle branch block (RBBB), 3 left bundle branch block (LBBB), and 2 with both. Bundle branch block disappeared after a duration of 6.87 ± 11.26 s. Conclusion Effective refractory period (ERP) of His-Purkinje system at the beginning of AVNRT was modulated automatically within less than 30 - 60 s and thus facilitated nodal-ventricular conduction. The mechanism of this is electrical remodeling. Chin Med J 2000; 113(6): 490-492

Objective To study the relationship between isometric exercise and myocardial ischemia in patients with coronary artery disease (CAD). Methods Twenty CAD patients and 10 normal subjects were included in our study. All subjects performed maximal brief isometric exercise (BIE), maximal sustained isometric exercise (SIE) and dynamic exercise (DE). Hemodynamic parameters and cardiac function were measured by Echo-Doppler technique. To avoid influence of different baseline values, increment (△%) of exercise response was used as parameter for significant analysis: △% = (exercise values - baseline values)/baseline values x 100%. Results Positive exercise testing (PET) showed no evidence of myocardial ischemia during BIE and SIE even though their rates of perceived exertion (RPE) were similar to DE. △% heart rate (HR) and A% rate pressure product (RPP) were higher during DE than during SIE and BIE in negative exercise testing (NET) and normal controls (NOR) (P < 0.01), except PET during DE and SIE; △% systolic blood pressure (SBP) was higher during DE than during BIE in NOR (P < 0.01). △% SBP in NOR and NET during SIE was higher than during BIE (P < 0.05). △% diastolic blood pressure (DBP) was the highest during SIE among exercises in all groups (P < 0.05). There were no significant inter-group differences of △% HR, A% SBP, A% DBP and A% RPP during SIE, BIE and DE, except that △% SBP during SIE was higher in NET than in NOR and PET (P < 0.05). In NOR, A% ejection fraction (EF), △% fractional shortening of the minor-semi axis (SF), △% cardiac output (CO), A% E/A was higher during DE than during SIE and BIE (P < 0.01). △% stroke volume (SV) was similar during DE, SIE and BIE. There were no significant differences in △% EF, △% SF, △% CO, △% SV and A% E/A during DE, SIE and BIE in both NET and PET, except lower △% CO in NET during SIE and BIE than DE (P < 0.01). There were no inter-group differences in △% EF, △% SF, △% CO and A% E/A, except that △% E/A was higher during SIE in NET than PET (P < 0.01). During DE, NOR and NET had higher △% SV, △% SF, △% CO and A% E/A than PET (P < 0.05). Conclusions The incidence of myocardial ischemia in CAD patients was lower during isometric exercise than dynamic exercise at similar perceived exertion levels. Isometric exercise might protect the myocardium from ischemia through high coronary artery perfusion pressure and long perfusion duration. We suggest that application of isometric exercise in a cardiac rehabilitation program may have reasonable physiological background. Chin Med J 2000; 113(6): 493-497

Objective To study the effect of arsenic trioxide (AS2O3) on non-APL acute myeloid leukemia (AML) cells and the interreactive effect between retinoic acid (RA) and AS2O3. Methods RA-sensitive (S) and RA-resistant (R) HL-60 non-APL AML cells were used as an in vitro model. Cell number and trypan blue were used to observe cell growth and survival. Apoptosis was determined by morphological changes, using a DNA laddering assay, terminal deoxynucleotidyl transferase (TdT) fragment end labeling assay and a flow cytometry assay. Results As203 induced apoptosis in both HL-60S and HL-60R cells, As203-induced apoptosis was both time-and concentration-dependent in a therapeutically-achievable As203 range (0.25 - 4.0 μmol/L). Both all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9cRA) potentiated As2O3-induced apoptosis, as measured by quantitative TdT fragment end labeling and flow cytometry assays in both HL-60S and HL-60R cells (P < 0.05, for all RA + As203 combinations vs As2O3 alone in both sublines). Conclusions As203 may inhibit the growth of non-APL AML cells by promoting programmed cell death. RA can potentiate As203-induced apoptosis even in RA-resistant HL-60 cells in which the classical ATRA response pathway is repressed owing to a homozygous inactivating mutation in the retinoic acid receptor a. As2O3 can have clinical activity in non-APL cases of AML and the enhanced activity might result from the combined As2O3-RA therapy. Chin Med J 2000; 113(6): 498-501

Objectives To explore the clinicopathological significance of the expression of MUC2 (mucin 2) and MUC3 (mucin 3) genes in tissues of the normal gastric mucosa, intestinal metaplasia (IM) and gastric carcinoma. Methods MUC2 and MUC3 apomucins were detected by immunohistochemistry; MUC2 and MUC3 mRNAs were detected by in situ hybridization. Results In the normal stomach, antibody detecting MUC2 apomucin and oligonucleotide probe detecting MUC2 mRNA were not reactive with mucus-producing cells in the superficial epithelium and neck, which were weakly reactive with antibody and probe detecting MUC3. In the duodenum, MUC2 apomucin and mRNA were found at the peri- and supranuclear area of goblet cells, but MUC3 apomucin and mRNA were at the cytoplasm of goblet cells and columnar cells. MUC2 and MUC3 apomucins and its mRNAs were found in 85.2%, 88.9% and 31.6%, 57.1% of specimens of IM, 67.4%, 66.7% and 57.9%, 43.6% of specimens of gastric carcinoma. There were no associations between expressions of MUC2 and MUC3 genes and different types of IM. Patients with moderate/well differentiation had higher proportion of MUC2 apomucin expression than those with poor differentiation (P < 0.05), and patients with positive staining of MUC3 apomucin in the cancerous tissues had higher proportions of metastasis of lymph nodes (P < 0.01), serosal invasion (P < 0.05) and clinical stages Ⅲ-Ⅳ (P < 0.05). Conclusions MUC2 and MUC3 genes are mainly expressed in the mucosa of the duodenum, and marked expression is seen during the neoplastic transformation of stomach mucosa. MUC3 apomucin might have a poor prognostic significance. Chin Med J 2000; 113(6): 502-507

Objective To study the effects of high glucose and transforming growth factor-βi (TGF-β1) on the expression and function of glucose transporter-1 (GLUT1) in mouse mesangial cells. Methods Cultured mouse mesangial cells were used. The expression of GLUT1 mRNA was detected by Northern Blot; glucose uptake and its kinetics were determined with a 2-Deoxy-[3H]-D-glucose uptake assay. Results Mesangial cells exposed to enriched glucose medium (20 mmol/L) for 72 hours demonstrated a decrease in both GLUT1 mRNA and Vmax for uptake of the glucose analog, 2-deoxy-D-glucose (2DOG), as compared to mesangial cells cultured in physiologic glucose concentrations (5.5 mmol/L). In contrast, hypertonic mannitol had no effect on GLUT1 mRNA levels. TGF-β1 treatment for 10 hours stimulated 2DOG uptake, both in 5.5 mmol/L and 20 mmol/L glucose medium, by approximately 4.28-fold in a dose-dependent manner (2 ng/ml maximum). Kinetic analysis of 2DOG uptake revealed an increase in Vmax and a decrease in Km in the presence of TGF-β1. TGF-β1 also up-regulated the expression of GLUT1 mRNA in mesangial cells. The addition of anti-TGF-β neutralizing antibody (30 μg/ml) in mesangial cells cultured in enriched glucose medium (20 mmol/L) led to a 40% decrease in 2DOG uptake. Conclusions The expression of GLUT1 can be suppressed by exposure of mesangial cells to high glucose medium, which may serve as a protective mechanism against possible adverse effects of excessive glucose flux into cells. TGF-β1 stimulates glucose uptake by enhancing the expression and function of GLUT1 in mesangial cells. This effect is independent of the glucose milieu in the cultured medium. Chin Med J 2000; 113(6): 508-513

Objective To evaluate activator protein-1 (AP-1) mediated mechanisms in thrombin-induced qlasmino-gen activator inhibitor-1 ( PAI-1) expression in cultured human glomerular mesangial cells (MCs). Methods Electrophoretic mobility shift assay (EMSA) was employed to assess AP-1 DNA-binding activity, and Western blot hybridization was used for quantification of c-fos and c-jun, two subunits of AP-1 dimers. PAI-1 activity and mRNA expression were analysed by the fibrin plate assay and Northern hybridization, respectively. Results Thrombin concentration enhanced PAI-1 activity in the supernatant and stimulated PAI-1 mRNA expression in cultured MCs. PAI-1 activity was blocked by hirudin, a specific inhibitor of thrombin. Further study demonstrated that thrombin promoted AP-1 DNA-binding activity but exerted little effect on c-fos or c-jun. Curcumin (AP-1 inhibitor), staurosporine (PKC inhibitor), and genistein (PTK inhibitor) all reduced AP-1-mediated PAI-1 mRNA expression induced by thrombin in cultured MCs. Conclusion The present study indicates that in cultured human MCs, thrombin stimulates PAI-1 expression through an AP-1 signal pathway, which may be mediated by PKC and PTK. Chin Med J 2000; 113(6): 514-519

Objective To study the ultrastructural damages of brain tissues dynamically after middle cerebral artery obstruction (MCAO). Methods A middle cerebral artery obstruction (MCAO) model was reproduced in renal vascular hypertensive rats (RHR). Brain tissues in different locations were collected for eight times in row, from two hours to seven days after establishment of the animal model. Results The changes occurred in the whole brain after focal cerebral ischemia. The severity of impairment and time of emergence differed with the location sampled. The earliest in the infarcted region with necrosis was considered the major change and completely irreversible damage. The next was seen in marginal regions, mainly with microvascular collapse, formation of microthrombi, and partial necrosis of brain cells and was considered partially reversible damage. The last was in distant and contralateral hemisphere, mainly with reversible swelling of endothelial cells and astrocytes. Changes in the MCAO models reproduced by RHR models were much similar to the clinical pathological changes in cerebral infarction based on the hypertensive cerebrovascular impairment, and it was regarded as a relatively ideal model for studying focal ischemic cerebral impairment. Conclusion Dynamic changes of cerebral ultra-structure in which microvascular impairment plays an important role suggest that clinical therapy cannot only be focused on infarction foci, but also on the whole brain with comprehensively effective measurements. Chin Med J 2000; 113 (6): 520-524

Objective To study the activity of telomerase and the expression of its RNA in nasopharyneal carcinoma (NPC) and HNE1 cell lines of NPC. Methods Telomerase activity was detected with telomeric repeat amplification protocol (TRAP) PGR ELISA kit in 41 cases of NPC, 14 cases of tissues adjacent to the carcinoma, and 19 cases of chronic nasopharyngitis, HNE1 cell lines of NPC, HL60 cell lines of leukemia, TUL1 cell lines of lung cancer, as well as three other kinds of normal control cells. The sensitivity and specificity of telomerase assay were also analyzed. Moreover, the expression of human telomerase RNA (hTR) was studied in 27 cases of NPC, 19 cases of adjacent nasopharyngeal tissues, and 17 cases of control groups by RT-nested PGR. Results The telomerase activity was found increased in NPC and in tissues adjacent to NPC with absorbance value (A value) of 1.15 U±0.78 U and 1.04 U±0.67 U respectively, compared with chronic nasopharyngitis (A = 0.18 U ± 0.09 U). In NPC with cervical lymphnodes involvement the telomerase acitivity (A = 1.25 U ± 0.79 U) was higher than in those without involvement (A = 1.02 U ± 0.71 U), P < 0.05. The telomerase activity was also observed in HNE1, cell lines (A = 1.26 U ± 0.97 U) and in other two kinds of cancer cell lines, but not in the three kinds of normal control cells. By contrast, no significant difference was seen in the expression of hTR among the three nasopharyngeal biopsy groups (P > 0.05). Finally, the sensitivity of telomerase assay was high (at an amount of 102 HNE1, cells), and the specificity was also high (after inactivation by heat or RNase, the telomerase activity was very low). Conclusions A high frequency of telomerase activity is commonly seen in NPC, adjacent nasopharyngeal tissues, and HNE1, cell lines and is closely associated with NPC with cervical lymphnodes involvement. Both sensitivity and specificity of the telomerase assay are high. However, owing to the fact that the expression of hTR has no obvious difference between NPC and normal tissues and does not always correspond with the telomerase activity, it would be better to do TRAP as well as hTR assays for the activity and expression in assessing the carcinogenesis of NPC. So, more intensive study on the role of hTR in the carcinogenesis of NPC and on the exact relationship between hTR and telomerase is needed. Chin Med J 2000; 113(6): 525-528

Objective To investigate the therapeutic effects of the Chinese medicinal herb, Rhubarb, on severe brain injury. Methods Rhubarb extracts in ethyl alcohol and water were used to treat 20 patients with severe cerebral injury complicated by hyperthermia, renal failure, hemorrhage in the upper digestive tract, and increased intracranial pressure. Vital signs, variations of Glasgow coma scale (GCS) and intracranial pressure (ICP) of the patients were observed. The degree of hemorrhage in the digestive tract and the change in creatinine value were also observed. Other 20 patients served as controls. Results The result of the treatment group was more marked than that of the control group. Three days after administration of the rhubarb extract, the body temperature decreased by 1.1℃, ICP by 0.4 kPa (1 mm Hg = 0.1333 kPa) on average, and the incidence of hemorrhage in the digestive tract by 30%. The volume of hemorrhage of the digestive tract decreased by 700 ± 250 ml, and the time for turning occult blood to negative by 10%. Conclusion The Chinese medical herb, rhubarb, has multiple therapeutic effects on severe brain injury. Chin Med J 2000; 113(6): 529-531

Objective To compare the epidemiology, local and regional invasion and prognosis of head and neck malignant fibrous histiocytoma (MFH) and extremity MFH. Methods Between January 1, 1972 and December 31, 1993, 173 patients with MFH (71 head and neck, 102 extremities and trunk) were referred to the Cancer Hospital for surgical treatment. They were 101 men and 72 women, with age ranging from 13 to 83 years (median: 45 years). The extent of surgery was classified into radical, wide and local resection. Results For head and neck, local recurrence of MFH after wide resection was 80.4% (37/46), compared with 36.4% (8/22) after radical surgery (P = 0.000). The five-year survival was 50.79% in all the head and neck patients (74.75% in patients free of local recurrence, 37.74% in patients with local recurrence; P = 0.0181), compared with 70.71 % in extremity patients (P = 0.0005). Repeated surgery after recurrence of MFH could cure 40.9% of the head and neck patients and 80.7% of the extremity patients. Conclusion Inadequate resection of head and neck MFH in initial surgery is associated with a high incidence of local recurrence, which is always correlated with worse prognosis. Repeated surgery for recurrent head and neck MFH is not as effective as for recurrent extremity MFH. Therefore, we suggest that the initial surgery for head and neck MFH should be as radical as allowed to avoid a possible local recurrence. Chin Med J 2000; 113(6): 532-535

Objective To investigate the epidemiological and clinical manifestations of endemic arsenism, fluorosis and arsenic-fluoride poisoning caused by drinking water. Methods A total of 102 wells with high arsenic and fluoride level in water were selected. The residents were investigated before and after intervention for prevention and treatments and compared with controls. Results The residents' state of illness in the endemic area showed that arsenic and fluoride had independent actions respectively in their main clinical manifestations. In the endemic area, puberty of the children was retarded. And there was an obvious entanglement in the extremity microcirculation. More abnormal findings were found in electrocardiogram (ECG) and electromyogram (EMG). Birth weight of the babies was less than that of the controls. Patients with skin tumors and carcinoma of the esophagus were found prelavent. Improvement occurred in 81.7% of arsenism patients and no new case was found one year after the quality of the water was improved. Conclusions Arsenic and fluoride are able to produce toxic effects independently at levels of 0.1 mg/L or more of arsenic and 1 mg/L or more of fluoride. It suggests each of arsenism, fluorosis or arsenic-fluoride poisoning is a systematic disorder. After one year of drinking reformed water the clinical manifestations were improved.

Purpose To review the recent developments in asthma research in China, presenting the background of further asthma research and promoting academic exchanges between Chinese and foreign respirologists. Data sources A literature search was conducted using 5 authoritative journals covering the years 1994 -1998. Study selection Sixty-seven of 238 asthma-remated original articles published between the years 1994 -1998 were selected to reflect the recent developments in asthma in China. Data extraction The papers reviewed pertain mainly to the epidemiology, genetics, pathogenesis, prevention and treatment of asthma. Results Since 1993, the hot topics in asthma research in China have been pathogenesis, prevention and treatment. There has been relatively less investigation into the genetics of asthma in China. An epidemiological survey of asthma has been conducted in parts of China and was reviewed. Conclusions More and more attention has been paid to the study of asthma during the last five years in China. The prevalence of asthma has increased in recent years. The study of the pathogenesis of asthmatic airway inflammation has made further progress, which will help the management and treatment of asthma. The treatments for asthma, including herbal medicine, have been explored and the clinical efficacy of inhaled corticosteroids has been established. Chin Med J 2000; 113(6): 483-489