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Biomedical subjects

K Chen

Publications and source records attributed to K Chen.

At least 253 records · Page 14Linked to original sources
PubMed1998

Abnormal stress response and increased fighting behavior in mice lacking the bcr gene product.

The in vivo function of proteins which regulate activity of the GTPase Rac is largely unknown. Here we establish that mice lacking bcr, a known GTPase activating protein for Rac, exhibit a defect in the regulation of both hormonal and behavioral stress responses. Bcr null mutants demonstrate prolonged elevation of plasma glucocorticoids and increased fighting in males in response to physiological and social stress, respectively. Combined biochemical and behavioral data indicate that bcr is involved in mediating the cellular effects of glucocorticoids, specifically down-regulation of the stress-activated hippocampal hypothalamic-pituitary-adrenal axis.

Aggression↗
PubMed1998

Recent progress in the development of tubulin inhibitors as antimitotic antitumor agents.

Tubulin protein is a major target of drug molecules, and consequently, tubulin inhibitors have attracted great attention as antimitotic antitumor agents for chemotherapeutic use. Hundreds of synthetic or semisynthetic tubulin inhibitors have been discovered and developed recently that are related to the natural products colchicine, vinblastine, and taxol. Representatives include allothiocolchicinoids, vinorelbine, and taxotere. This review will describe the recent progress being made in the development of novel antimitotic antitumor tubulin inhibitors. The emphasis has been placed on related research in the author's laboratory, including development of colchicine derivatives and other colchicine binding site drugs, such as flavonoids and quinolone derivatives. Syntheses and modifications of novel compounds, biological activity evaluation, and structural activity relationships will be discussed as well. Further research will undoubtedly lead to the discovery of additional tubulin inhibitors that have potential for use as anticancer drugs.

Antineoplastic Agents↗
PubMed1998

[Short-and long-term therapeutic effects of brachytherapy on intracavitary residual tumor in 563 nasopharyngeal carcinoma (NPC) patients].

OBJECTIVE: To evaluates the effect of brachytherapy on intracavitary residual tumor in patients with NPC after external radiation therapy. METHODS: Five hundred fifty three NPC patients with residual tumor in the nasopharynx were treated with large dose brachytherapy (20-25 Gy). The treatment results were retrospectively evaluated. RESULTS: Within 3 months after brachytherapy, the overall regression rate of the residual tumor was 90.4%. Upon long-term follow-up, the 1-, 3-, and 5-year survival rate was 89.6%, 67.0% and 55.4%, respectively. The major complications of the after-loading treatment were nasal obstruction (16.2%), necrosis of the naso-pharynx (0.9%) and perforation of soft palate in 2 patients. CONCLUSION: Brachytherapy is effective in the treatment of residual NPC especially in patients in early stage. It may not be helpful for stage IV patients.

Adolescent↗
PubMed1998

[Expression of mdr-1 gene in cancer tissue and its association with morphological indexes of esophageal carcinoma].

OBJECTIVE: To detect the levels of mdr-1 gene expression in fresh untreated esophageal carcinomas, and to correlate these levels to current prognostic indicators of morphology. METHODS: mdr-1 gene expression of 46 untreated esophageal carcinoma was investigated with reverse transcription polymerase chain reaction (RT-PCR), and compared with the positive incidences among differentiated grades, TNM stages and macroscopic types of cancer. RESULTS: All 46 samples were pathologically squamous cell carcinoma. The positive incidence of mdr-1 gene expression was 37% (17/46) in the whole group, and 35% (6/17), 40% (8/20), 33% (3/9) for differentiated grade I, II and III respectively. The expression rate of 33% (6/18), 40% (5/12), and 37% (6/16) was for TNM stage IIa, IIb, and III respectively. Macroscopically, the positive incidence was 37% (3/8) in constrictive, 33% (5/15) in fungating, 40% (6/14) in medullary, and 33% (3/9) in ulcerative type. There were no significant differences in each category system of morphology. CONCLUSION: Because of highly expressive level of mdr-1 gene in untreated esophageal carcinoma, we should choose appropriate chemotherapeutic regimen for esophageal Ca. The expression of mdr-1 gene in untreated esophageal cancer was independent of morphologic prognostic indexes without correlation between mdr-1 gene expression and morphological indexes.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1998

[A molecular and epidemiology study in patients with ventilator-associated pneumonia].

OBJECTIVE: To evaluate causative agents in patients with ventilator-associated (VA) pneumonia epidemiologically, then to provide useful suggestion for diagnosis and treatment of VA pneumonia. METHOD: Prospectively, a protected specimens brush was used to obtain the secretion of lower respiratory tract of 65 patients, who had been receiving mechanical ventilation or tracheostomy for more than 72 hours. At the same time, other samples were collected from the relevant places, including pharyngeal and gastric juice of patients as well as other persons, ward's air. The secretion obtained were cultured with a quantitative method. Then all bacteria isolated were studied with the analysis of pattern of plasmids and chromosomal restriction endonuclease. RESULT: It was showed that the route of infection of the Gram-negative bacilli in VA pneumonia (19 cases) was intrinsic, a retrograde colonization from patient's stomach, that was the pattern of clonization from stomach to pharynx, then into lower respiratory tract, and the Gram-positive staphylococcus spread mainly through the ward's air, then directly into lower respiratory tract, or extrinsic (20 cases). CONCLUSION: The Gram-positive staphylococcus is also major disease-producing germs in VA pneumonia, and the infection routes of G+ and G- bacteria might be different.

Adult↗
PubMed1998

[Effect of purified Xuefu capsule on cardiac haemodynamics and oxygen consumption in acute myocardial ischemia of experimental dogs].

OBJECTIVE: To investigate the effect of Purified Xuefu Capsule (PXC) on cardiac haemodynamic and oxygen consumption in acute myocardial ischemia of experimental dogs. METHODS: The coronary arteries was ligated to create the myocardial ischemic modle and gave them PXC through the duodenum. The effect of PXC on the systolic and diastolic function, volume of blood flow in coronary arteries and cardiac output of acute ischemic heart of experimental dogs were examined. RESULTS: After ligation of the coronary artery the myocardial ischemia was formed, the systolic and diastolic function, volume of blood flow in coronary arteries and cardiac output were decreased significantly in the control group, whereas these indexes in high-dose and low-dose PXC group were improved to some extent, the effect of high-dose PXC group was better than that of the low-dose PXC group. Furthermore high-dose PXC could reduce the oxygen consumption. CONCLUSIONS: PXC could prevent the cardiac pump function from acute myocardial ischemia of experimental dogs. The mechanism may be related to reduce the oxygen consumption and increase the blood supplement to myocardium.

Animals↗
PubMed1998

[Clinical study of physiological age in accordance with the integration of traditional Chinese and Western medicine].

OBJECTIVE: TCM and western geriatric medical principles were used to study the assessment of aging in mankind. METHODS: The authors studied and examined 387 healthy subjects ranging from 45 to 69 years of age. Its indices included 24 TCM senility syndromes, 5 western medical neurophysiological indices. Thereafter, regression analysis was used to deduce a TCM-WM aging formula. RESULTS: Data from all clinical subjects were processed using integrated TCM-WM, physiological age formula to determine the physiological ages (Y) and their corresponding calendar ages (y). The mean values of the age differential of zero, and a standard deviation of 2.29 years were calculated. From statistical view point, a 95 percentage is an acceptable normal value range. Also, as the objective of the aging assessment only used the higher end of the range. I.E., it is considered there is excessive aging when physiological age is higher than calendar age by 3.37 years. In the process of conducting regression analysis, the authors also discovered that LPO can increase TCM senility syndrome score, whereas CuZnSOD decrease it. CONCLUSIONS: The above clinical study showed that the regression analysis and age-related TCM indices can comprehensively reflect the natural process of aging in mankind. It also demonstrated the highly predictive nature of TCM senility syndrome score.

Aged↗
PubMed1998

[Effect of xuefu zhuyu pill on blood stasis syndrome and risk factor of atherosclerosis].

OBJECTIVE: To observe the effect of Xuefuzhuyu Pill (XFZYP) on blood stasis syndrome and risk factor of atherosclerosis. METHODS: Fifty-seven patients of atherosclerosis were randomly divided into XFZYP group (30 cases) and aspirin group (27 cases) treated with XFZYP (6 g, three times daily) and aspirin (40 mg per day) oral taken respectively for one month. RESULTS: XFZYP could improve blood stasis syndrome of patients (P < 0.01) and reduced the level of risk factor of atherosclerosis, including high blood cholesterol (P < 0.01), oxidation of low density lipoprotein (P < 0.05) and plasma granule membrane protein alpha (P < 0.01). CONCLUSION: XFZYP is beneficial to retard the progress of atherosclerosis.

Aged↗
PubMed1998

[Clinical study on effect of huancongdan capsule in treating senile vascular dementia].

OBJECTIVE: To observe the effect of Huancongdan (HCD) capsule on senile vascular dementia (SVD). METHODS: Seventy two cases of SVD were divided randomly into two groups. The HCD group (37 cases) were treated with HCD and the control group (35 cases) treated with Hydergine. RESULTS: After 2 months of treatment, the clinical symptoms, hyponeural defect, self-care capability and abnormal ratio of whole blood viscosity to plasma viscosity in HCD group were significantly different as compared with before treatment (P < 0.05). CONCLUSION: The effect of HCD for treatment of SVD was affirmative.

Aged↗
PubMed1998

[Clinical study of purified xuefu capsule in treating angina pectoris].

OBJECTIVE: To study the effect of purified Xuefu Capsule (PXFC) in treating angina pectoris (AP). METHODS: Fifty-seven patients with AP were randomly divided into two groups. Group A (30 cases) was treated with PXFC and western medicine, and group B(27 cases) with western medicine (isosorbide dinitrate, diltiazem or atenolol) alone. RESULTS: The total effective rates and ECG ST-T changes of AP were 93.3% and 63.3% respectively in group A. These results were all superior to those of group B (P < 0.05). Moreover, in group A the level of plasma endothelin (ET-1) decreased from 85.09 +/- 37.56 ng/L to 61.19 +/- 4.02 ng/L, and that of calcitonin gene related peptide (CGRP) increased from 58.64 +/- 19.30 ng/L to 88.87 +/- 20.41 ng/L. Comparing with group B, these changes were statistically different (P < 0.01). CONCLUSIONS: The effects of adding PXFC on conventional treatment with western medicine were better than those of western medicine.

Aged↗
PubMed1998

[Clinical study on effect of concentrated xuefu zhuyu pill on restenosis of 43 cases coronary heart disease after intracoronary stenting].

OBJECTIVE: To explore the clinical effectiveness of concentrated Xuefu Zhuyu Pill (CXZP) on restenosis (RS) of coronary heart disease (CHD) after intracoronary stenting. METHODS: Eighty-four successful intracoronary stenting patients were randomly divided into conventional treatment group (control group, 41 cases) and conventional treatment plus CXZP group (treated group, 43 cases). The follow-up underwent for 6 months. Clinical symptom, change of blood stasis were observed. And occurrence of restenosis was estimated by ECG exercise treadmill testing, emission computed tomography (ECT) and coronary angiography (CAG). RESULTS: The symptoms of blood stasis of treated group improved in the follow-up significantly (P < 0.01), and the integral of blood stasis were decreased significantly in the treated group vs the conventional treatment group (P < 0.01). The recurrent angina pectoris rate of the treated group was lower than the conventional treatment group (P < 0.01). The 61.9% of 84 patients reexamined the CAG in the follow up, and the lower restenosis rate (25.8%) in the treated group than in the conventional treatment group (32.1%, P = 0.59). CONCLUSION: There is the trend that CXZP could prevent restenosis. Therefore, it is necessary to increase the cases for further study of CXZP on preventing restenosis.

Adult↗
PubMed1998

[Study on effect of Erigeron injection in prevention and treatment of cerebral ischemic injury].

OBJECTIVE: To study the effect of Erigeron injection (EI) on cerebral ischemic injury. METHODS: Animal model of brain ischemic/reperfusion was established in male Wistar rats and the effect of EI on proteinkinase C (PKC) activity, intraneuronal free calcium and regional cortex blood flow (rCBF) were observed. RESULTS: EI could prevent the activation of PKC, calcium overload and decrease of RCBF induced by cerebral ischemia/reperfusion. CONCLUSION: EI could prevent neuronal ischemic injury by inhibiting activation of PKC.

Animals↗
PubMed1998

[Diagnosis and surgical treatment of pituitary microadenoma].

OBJECTIVE: Through the experiences of clinic picture and the radiologic characteristics of eleven cases of micropituitary adenomas, the early diagnosis and surgical indications were discussed. METHODS: Intensified CT and MRI were used to compare their significances in the diagnosis of micropituitary adenomas. Kaltai incision of the nares and transsphenoidal approach were adopted in these cases. RESULTS: The bulging of the upper border of the pituitary gland and the shifting position of the pituitary stalk observed in the intensified MRI are the pathognomonic signs for the diagnosis of micropituitary adenoma. The operation was stopped due to hemorrhage in one case. The average following up was 3.2 years past operative death in the second month in one case, operative failure in one case and loss of following up in one case. CONCLUSION: Strict selection of surgical indications must be done necessary after careful study of MRI.

Adenoma, Chromophobe↗
PubMed1998

[Clinical effect of tianma-cuzhi granules on senile vascular dementia].

OBJECTIVE: To assess the clinical efficacy of Tianma-cuzhi Granules (TMC) in treating senile vascular dementia(VaD) of the "sthenia of liver-yang" type. METHOD: TMC were given to thirty VaD patients three times a day of 0.5 g/bageach. The treatment course was one month and the patients finished two consecutive courses. RESULTS: TMC could markedly increase the mini-mental state examination (MMSE) and Hamilton depression scale(HDS) marks of VaD patients, and also contribute to improving certain indexes especially in abnormal cases. CONCLUSION: TMC have certain effects on senile VaD.

Aged↗
PubMed1998

[Observation of antiarrhythmic effects of Cinnamomum migao H. W. Li on experimental arrhythmia].

OBJECTIVE: To investigate the effects of Cinnamomum migao on experimental arrhythmia. METHOD: Arrhythmic models of mice, rabbits, guinea pigs and rats were built using chloroform(Chl), adrenalin(Adr), strophanthin-K (Spt-K) and barium chloride (BaCl2). The affected animals were divided randomly into three groups: control group, Cinnamomum migao (CV-3) group and mexiletine (MXL) group, so as to observe and compare the antiarrhythmic effects. RESULT: CV-3 could reduce the incidence of ventricular fibrillation caused by ch1 in mice and the ventricular tachycardia induced by Adr in rabbits, delay the onset time of this arrhythmia, increase the arrhythmic doses of Spt-K in guinea pigs, reduce the incidence of some arrhythmia caused by BaCl2 in rats and slow down their heart rate. CONCLUSION: CV-3 has obvious antiarrhythmic effects on experimental arrhythmia. The mechanism of these effects is probably related to the arrest of the intraflow of Na+, Ca2+ in the cardiac cells and the depression of their cardiac autoarrhythmicity and conductivity.

Animals↗