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Biomedical subjects

L Chen

Publications and source records attributed to L Chen.

At least 721 records · Page 40Linked to original sources
PubMed1998

[Alterations of intracellular free calcium concentration of cerebral neuronal cells in infectious brain injury in rats].

Intracellular free calcium concentration, [Ca2+]i, of cerebral synaptosomes loaded by Fura-2/AM was measured by fluorescent method to clarify alterations of [Ca2+]i in infectious brain injury (IBI) in rats. The results showed that [Ca2+]i, water content (WC), and Evans blue content (EB) in groups injected by Bordetella pertussis suspension (BP) were increased compared to those in groups injected by normal saline (NS) at 0.5 h, 4 h, and 24 h, respectively. Increased [Ca2+]i in BP groups showed time-dependent relationship and the highest level in the 24 h group. There was positive correlation (0.5 h, 4 h) and no correlation (24 h) between [Ca2+]i and WC or EB. It is suggested that [Ca2+]i accumulation of cerebral neuronal cells plays an important role in the pathogenetic mechanism of the acute and delayed IBI induced by BP.

Animals↗
PubMed1998

[Estimation of cytosolic free calcium within synaptosomes with fluorescene indicator Fura-2].

Intracellular free calcium [Ca2+]i concentration has become a focus of attention for investigators in the field of brain edema. It is the purpose of the present study that the changes of the concentration of the free calcium within cortical neurons were investigated on the model of brain edema induced by freezing injury. [Ca2+]i was determined in calcium fluorescent indicator Fura-2/AM loaded neuronal synaptosomes by using mono-wave length spectrofluorophotometer. The method for preparing synaptosomes, and the method and mechanism of concentration of cytosolic free calcium using fluorescent indicator Fura-2/AM were studied.

Animals↗
PubMed1998

[Orthogonal design-direct analysis for PCR optimization].

Polymerase chain reaction (PCR) optimization is difficult but very important. It is hard to gain the optimal condition due to the confusion of too many factors influencing the experiment. We report a new method, orthogonal design-direct analysis, which has been confirmed to be scientific and easy to follow by many times of PCR.

Brain Neoplasms↗
PubMed1998

[The relationship between laminin and laminin receptor expression to metastasis and survival of breast carcinomas].

OBJECTIVE: To investigate the relationship between laminin (LN) and LN receptor (LN-R) expression to breast carcinoma metastasis and survival. METHOD: The LSAB immunohistochemical method was used to study cytoplasm of primary breast cancer tissue from 109 cases and 37 axillary lymph nodes with metastasis. RESULTS: Immunostaining of LN was detected in 32 (29.4%) primary breast carcinoma and in 5 (13.7%) axillary nodes with metastasis. The expression of LN-R was significantly lower in primary breast carcinomas (55.0%) than in the node-positive tissues (83.8%) (P < 0.05). Among the 64 cases followed up none of the 6 patients with LN positive alone died after 3 years. Whereas, the LN-R positive (including LN-R positive alone or both LN and LN-R positive) cases had a significantly poorer prognosis when compared with the LN-R negative cases (P < 0.001). Multivariate analysis of clinical and pathological data by Cox regression method demonstrated that both LN-R expression and lymph node status were independent factors affecting the survival of breast cancer patients, but the former had a higher risk (odds ratio = 4.375) than the latter (OR = 2.810). CONCLUSION: These results suggest that LN-R expression is an important biofactor for predicting the prognosis of breast cancer.

Adult↗
PubMed1998

[Placental site trophoblastic tumor: a study of clinicopathologic features and differential diagnosis].

OBJECTIVE: To study the clinicopathologic features and differential diagnosis of placental site trophoblastic tumor (PSTT). METHODS: 5 PSTT cases were studied and compared with 10 choriocarcinoma cases and 2 exaggerated placental site (EPS) cases by light and electron microscope examination and immunohistochemical staining. RESULTS: PSTT occurs in reproductive women and often following term deliveries. Amenorrhea and or vaginal bleeding are common presenting symptoms. The serum levels of hCG are often slightly or moderately elevated. Microscopically, PSTT is composed of only one kind of trophoblast cell, displaying extensive invasion of myometrium and vessels without obvious hemorrhage and necrosis. Mitotic figures are not common. Ultrastructure shows that the tumor cells contain prominent paranuclear filaments. Immunohistochemical reaction reveals positive staining for hPL and mostly negative staining for hCG. CONCLUSION: PSTT is a rare trophoblastic tumor with unique microscopic, ultrastructural and immunohistochemical features which can help to differentiate them from other trophoblastic diseases.

Choriocarcinoma↗
PubMed1998

Serum levels of epinephrine and norepinephrine in cirrhotic patients with portal hypertension.

OBJECTIVE: To investigate the role of catecholamines in the pathogenesis of portal hypertension. METHODS: Serum epinephrine (E) and norepinephrine (NE) concentrations in the peripheral vein, portal vein and superior vena cava (SVC) were measured by high pressure liquid chromatography in 38 portal hypertensive patients, 28 idiopathic hypertensive patients and 34 controls, respectively. RESULTS: Peripheral venous E concentrations in portal hypertensive patients and controls were 57.5 +/- 37.4 ng/L and 23.5 +/- 11.2 ng/L, respectively (P < 0.01), and peripheral venous NE concentrations were 451.1 +/- 381.2 ng/L and 183.0 +/- 83.3 ng/L, respectively (P < 0.01). Compared with controls, peripheral venous E (54.9 +/- 39.9 ng/L vs 23.5 +/- 11.2 ng/L, P < 0.01) and NE (524.3 +/- 219.9 ng/L vs 183.0 +/- 83.3 ng/L, P < 0.01) in idiopathic hypertensive patients were also significantly increased. E and NE in SVC, portal vein and peripheral artery in portal hypertensive patients were also increased, but only the elevation of E in SVC was statistically significant (207.2 +/- 55.4 ng/L vs 83.7 +/- 46.7 ng/L, P < 0.05). CONCLUSION: Our results reveal significant metabolic disorders of E and NE in portal hypertensive patients, which may play an important role in the pathogenesis of portal hypertension.

Adult↗
PubMed1998

Horizontal platform supported total hip replacement.

OBJECTIVE: To investigate the effect of horizontal platform supported (HPS) prosthesis on cementless total hip replacement for surgical treatment of arthritis in a long-term follow-up study. METHODS: Clinical and radiographic follow-up of 65 consecutive primary cementless porous coated HPS total hip replacements, which were implanted in 60 patients between 1982 and 1989, was carried out. RESULTS: The 53 hips in 50 patients were evaluated both clinically and radiographically. The average follow-up was 6.8 years (range: 5 to 12 years). According to the Harris hip score, 52 (98%) of the hips had sustained an excellent or good result with an average score of 92. At the time of final assessment, no patient experienced anterior thigh pain. There were two revisions performed early in the series due to technical failures. Radiographically, osteolysis and bone remodelling were assessed. CONCLUSION: The findings suggest that the clinical and radiographic results after cementless total hip replacement for primary hip arthroplasty may be favourably influenced by the use of the proximal stress loaded HPS femoral component.

Adult↗
PubMed1998

[Expression of opioid-receptor-like receptor (ORL1) gene in rat brain].

In situ hybridization with a digoxigenin-labeled oligonucleotide probe was used to investigate the expression of opioid-receptor-like receptor (ORL1) gene in rat brain. It was observed that ORL1 mRNA is widely expressed in many regions of rat brain, particularly in cerebral cortex, thalamus, hypothalamus, amygdala, hippocampus, septum, habenula, periaqueducted gray, raphe nuclei and locus coeruleus structure. These findings suggest that ORL1 receptor may participate in modulating a number of physiological functions in the brain in addition to pain.

Animals↗
PubMed1998

[Determination of 10-hydroxy-2-decenoic acid (10-HDA) in Chinese traditional medicine preparations by high performance liquid chromatography].

This paper reports the quantitative determination of 10-HDA in Chinese traditional medicine preparations by HPLC. Spherisorb C18 column was used. The mobile phase consisted of methanol-distilled water and phosphoric acid(45:55:0.5, V/V). The elute was monitored at 210 nm. The good linearity was shown between the concentration of 10-HDA and peak area in the concentration range of 6.0-30.0 mg/L (r = 0.9999, n = 5). The detection limit was 0.2 mg/L (S:N = 3:1). The within-day and between-day RSD were 2.1%-2.2% and 2.9%-4.0%, respectively. Peaks of 10-HDA and impurities in these samples were separated completely. This method is simple, sensitive and accurate.

Antineoplastic Agents↗
PubMed1998

[Preparation of novel macroporous silica-based amide-polymer-bonded packing and its application to the separation of proteins].

A novel macroporous silica-based amide-polymer-bonded packing for protein separations in HPLC is described. The macroporous silica support was bonded with diethoxymethyl vinyl silane and then copolymerized with methylacrylamide and divinylbenzene to produce a tailored stationary phase with high resolution and inertness. The repeatability of packing preparation is good. They were characterized through the application of a standard protein mixture of pepsin, glucose oxidase, bean trypsinogen inhibitor and ribonuclease. The time for elution of these proteins is less than 12 minutes. It is suggested that the macroporous silica-based amide-polymer-bonded packing can be used to quickly separate biopolymer. This packing is a better alternative for the biopolymer separation.

Chromatography, High Pressure Liquid↗
PubMed1998

[Isotope tracer combined with trichloroacetic acid precipitation method for determination of nerve growth factor concentration in mouse plasma].

OBJECTIVE: To establish the radioisotope (125I) tracer method combined with trichloroacetic acid (TCA) precipitation for the determination of nerve growth factor (NGF) in mouse plasma. METHODS: Radioisotope tracer labelling method combined with TCA precipitation was used to determine NGF in mouse plasma. RESULTS: The detection limit of the method for NGF in plasma was 2.0 ng/ml. The intra-assay cv (CV) and the inter-assay CV were all less than 10%. The assay linearity was determined over the range of 12.5-400 ng/ml in plasma and the correlation coefficient was 0.9990. The average recovery of the method for NGF was 95.21%. CONCLUSIONS: The radioisotope tracer method combined with TCA precipitation is stable, sensitive and reliable. It is suitable for the determination of NGF concentration in mouse plasma.

Animals↗
PubMed1998

[Determination of telomerase activity in BALF cells from lung cancer patients].

OBJECTIVE: To investigate the telomerase activity in BALF cells from patients with lung cancer. METHOD: The silver staining and PCR technique were used to detect the telomerase activity in BALF cells from 30 patients with lung cancer and 30 patients with chronic bronchitis or benign pulmonary diseases. RESULT: The telomerase activity in BALF cells was positive in all the patients with lung cancer (25/30, 83%), and in none of the patients with chronic bronchitis or benign pulmonary diseases (0/30, 0%). The difference was highly significant (P < 0.001). In the same patient with lung cancer, the positive rate of telomerase activity was 83% in BALF cells from the diseased lung, but only 27% in BALF cells from the normal lung (P < 0.001). CONCLUSION: The telomerase activity may be used as a diagnostic marker for lung cancer. There is a correlation between telomerase activity and the development of lung cancer.

Adenocarcinoma↗
PubMed1998

[Morphological characteristics of fruits and seeds of Chinese Caesalpinia and its taxonomic significance].

OBJECTIVE: To set up a toxonomic approach to the morphological characteristics of fruits and seeds of Chinese Caesalpinia. METHOD: The ripe fruits collected in the field are dried in the shade, are surveyed and described and the fruit's and seed's morphological characteristics. RESULT: The interspecific differences of morphological characteristics among the fruits and seeds are obvious. The characteristics are stable. A key for their identification is given. CONCLUSION: The above approach can be used as the taxonomic criteria for species differentiation.

Caesalpinia↗
PubMed1998

[Isolation of and intracellular calcium mobilization in vestibular hair cells of the patients with acoustic neuroma].

OBJECTIVE: To further understand the biological features of the human vestibular organ. METHODS: Vestibular hair cells were isolated from patients with acoustic neuroma during the surgery and intracellular free calcium concentration of the cells was monitored with calcium-sensitive dye Fura-2 and digital imaging microscopy. RESULTS: Isolated vestibular hair cells were mainly of type I and could survive about 2.5 hours in vitro. Perfusion with 150 mmol/L KCl, induced a depolarization, resulting in a temporary increase of 340 nm/380 nm ratio from 0.52 to 1.16 within 1 min. In Ca2+ free environment, 150 mmol/L KCl failed to induce intracellular calcium increase. In the presence of 2.5 mumol/L ionomycin, there was an irreversible increase in 340 nm/380 nm ratio. CONCLUSION: Human vestibular hair cell apparently possess voltage sensitive calcium channels. The method and observation aid in elucidating human vestibular biological features.

Aged↗
PubMed1998

[The effect of Vit. B12 injection into acupoints in the treatment of verruca plana].

OBJECTIVE: To study the therapeutic effect of combined western and traditional Chinese medicines for the treatment of verruca plana. METHODS: Acupoint injection of Vit. B12 was used to treat 91 patients suffering from verruca plana after unsuccessful therapy of more than 3 methods. RESULTS: Complete cure, 35 cases; significantly improved, 56 patients. The total effective rate was 100%. Compared with the Vit. B12 i.m. injection group and polyinosinic cytidy lic acid i.m. injection group, the difference was highly significant (P < 0.001). The results were also proved by histologic examination. CONCLUSION: The Vit. B12 acupoints injection is a simple and effective method for the treatment of facial verruca plana.

Acupuncture Points↗
PubMed1998

[Reoperative treatment of recurrent retroperitoneal tumor].

OBJECTIVE: To improve the resection rate and survival rate for recurrent retroperitoneal tumor (RRT). METHOD: We analysed 34 patients with RRT who were treated in our hospital from 1987 to 1995. One patient had benign tumor, the others malignant. Because 7 patients were operated on over one time, we performed 53 operations including complete resection in 42 patients, palliative resection 8 and biopsy 3. RESULT: The 1-and 2-year survival rates for complete resection cases were 71.2% and 65.3%. The patients who received palliative resection and biopsy died within one year. CONCLUSION: The diagnosis, preoperative preparation and intraoperative management of RRT are important to operative safety and survival rate. We emphasize the importance of reoperation and complete resection for RRT.

Adolescent↗
PubMed1998

[Apoptosis and expression of PCNA in superficial transitional cell bladder cancer as related to recurrence].

OBJECTIVE: To determine the expression of apoptosis and PCNA in superficial transitional cell bladder cancer and to evaluate its significance as a recurrence marker. METHOD: 87 cases of superficial transitional cell bladder cancer were analysed for the expression of apoptosis and PCNA by using the 3-end labeling method of DNA and immunohistochemical staining in tissue sections. The apoptotic indexes and PCNA indexes were respectively the percentages of apoptotic cells or PCNA positive cells among tumor cells. RESULT: The end labeling method allowed a precise evaluation of the expression of apoptosis. Apoptosis occurred in 89.6% of superficial transitional cell bladder cancer. In 17 patients who suffered from tumor recurrence, the ratio of apoptosis indexes to PCNA indexes was significantly higher than that in those without recurrence (P < 0.01). CONCLUSION: The ratio of apoptosis indexes to PCNA indexes was believed to be related to tumor recurrence and might be of value in the assessment of recurrence of superficial transitional cell bladder cancer.

Adult↗