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Biomedical subjects

F Chen

Publications and source records attributed to F Chen.

At least 289 records · Page 16Linked to original sources
PubMed1999

Synthesis and characterization of multiply-tyrosinated, multiply-iodinated somatostatin analogs.

Radio-labeled somatostatin analogs have recently gained popularity as agents useful in intraoperative tumor localization, external scintigraphy and in situ radiotherapy. We have synthesized and characterized a series of novel N-terminally extended multiply-tyrosinated somatostatin analogs that possess high binding affinity for somatostatin receptors, exhibit biological activity comparable to the native peptide and retain these characteristics after iodination. These analogs can be radio-iodinated to high specific activities. Following radioiodination, these analogs exhibit minimal radiolysis and may be clinically useful for tumor localization, scanning and therapy.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1999

Age-Dependent Changes in the Effects of Amiodarone on Rabbit Cardiac Myocyte Contractions.

BACKGROUND: Intravenous amiodarone has increasingly been used to control life-threatening atrial and ventricular arrhythmias. In addition to its four antiarrhythmic properties, amiodarone may have complex effects on intracellular Ca(2+) stores and myocyte contractility. METHODS AND RESULTS: Contraction amplitude was recorded for cardiac ventricular myocytes isolated from neonatal and adult rabbits. Sarcoplasmic reticulum (SR) Ca(2+) stores were loaded to steady-state levels by a train of eight electric field stimulations. The SR Ca(2+) load was quantified by recording the contraction amplitude resulting from the complete depletion of SR Ca(2+) stores by exposing the cell to a 1-second pulse of 10 mmol/L caffeine. After the cells were exposed to 1 µmol/L amiodarone for 10 minutes, electrically stimulated contraction amplitudes significantly decreased in both adult and neonatal cells. Caffeine-induced cell contraction amplitudes were not affected by amiodarone in adult ventricular myocytes. By contrast, amiodarone markedly inhibited caffeine-induced contractions in neonatal ventricular myocytes. The inhibitory effect of amiodarone on the caffeine-induced contractions was not replicated by Ca(2+) channel blockade with diltiazem. CONCLUSIONS: Amiodarone markedly inhibits caffeine-induced contraction in neonatal myocytes but has no significant effect on adult myocytes. Ca(2+) influx through amiodarone-sensitive Ca(2+) channels may play a primary role in maintaining SR Ca(2+) stores in neonatal heart.

Journal Article↗
PubMed1999

Imaging features of focal intrahepatic extramedullary haematopoiesis.

The imaging findings of focal intrahepatic extramedullary haematopoiesis (EMH) in a 51-year-old woman with beta-thalassaemia intermedia are described with particular reference to MRI and CT. Bone marrow colloid scintigraphy was unhelpful in confirming the diagnosis, which was made from fine needle aspiration. This is the first description of stellate scars occurring in an EMH lesion. A review of the radiological appearances of this rare condition is presented.

Female↗
PubMed1999

Mediastinal thoracic duct cyst.

A healthy 34-year-old man had a mediastinal cyst on the imaging study. Surgical treatment was performed. The cyst was diagnosed as a thoracic duct cyst from its anatomic location and contents. Pathologic examination found it to be consistent with thoracic duct cyst. Endothelial cells on its luminal surface were identified by an immunohistologic stain with the factor VIII-related antigen. Twenty-six cases of thoracic duct cysts have been reported. We report an additional case and review the previously reported cases. We found that the ligation of the inferior pedicle of the cyst is essential to prevent postoperative chylothorax.

Adult↗
PubMed1999

A case of endobronchial endometriosis treated by subsegmentectomy.

We present a case of endobronchial endometriosis with catamenial hemoptysis. The lesion was diagnosed as endobronchial endometriosis using helical CT, and the patient underwent a subsegmentectomy of the upper part of the lateral basal segment. A histopathologic examination of the resected specimen revealed findings typical of endobronchial endometriosis with intimal hyperplasia within the bronchus. Since the operation, the patient has been asymptomatic for 11 months with no recurrence of hemoptysis.

Adult↗
PubMed1999

Evaluation of hand and finger heat loss with a heated hand model.

A heated full-scale hand model has been used to determine indirectly hand and finger heat losses of human subjects exposed to four ambient cold conditions (0, 4, 10 and 16 degrees C, air velocity approximately 0.3 m/s). Heat transfer coefficients determined with the hand model, were used to calculate heat flux based on measured skin to ambient temperature gradients. The responses of eight subjects from a previous study were used for the analysis. The measurements were carried out in a small climate chamber which was cooled by evaporating liquid carbon dioxide. The thermal hand was put into the chamber in a vertical position with the thumb up. The surface temperature of the thermal hand was controlled at 21, 25, 28, 31 and 34 degrees C under each of the four ambient cold conditions, in order to investigate possible temperature dependence of the calculated combined convective and radiate heat transfer coefficient (hCR). The value of hCR varied between approximately 9-13 W/m2 degree C for fingers and palm and back of hand, respectively. Calculated heat losses showed significant individual variation, corresponding to the maintained skin to ambient temperature gradient. Individual values from about 50 to more than 300 W/m2 were calculated. Several subjects showed CIVD and heat fluxes associated with this phenomenon were sometimes doubled. The measurement results showed realistic and comparable with literature date. The advantages of the thermal hand model can be counted as easy to use; directly measures the heat loss; highly reproducible and no interruption. It appears that a heated hand model provides a useful methods for analysis and quantification of hand heat loss.

Body Temperature Regulation↗
PubMed1999

Dose-dependent effects of DNA-damaging agents on p53-mediated cell cycle arrest.

We examined the dose-dependent effects of DNA-damaging agents on G1 arrest in isogenic human cell lines differing in their p53 status. As expected, 5 or 20 Gy of ionizing radiation induced a p53-dependent G1 arrest. In contrast, UV light or actinomycin D induced a modest G1 arrest that was p53-dependent only at lower doses. At higher doses, cells were arrested in G1 in a p53-independent manner coinciding with inhibition of RNA synthesis and abolished cyclin E expression. Interestingly, expression of cyclin E was enhanced after exposure to moderate doses of UV light and actinomycin D, and this enhancement was suppressed by wild-type p53. We propose that agents inducing transcription-blocking DNA lesions will at higher doses inhibit the progression of cells into S phase by a p53-independent mechanism involving the attenuation of E2F-mediated transcription of genes, such as cyclin E.

Blotting, Western↗
PubMed1999

[The relationship between apolipoprotein E gene polymorphism and coronary heart disease and arteriosclerotic cerebral infarction].

OBJECTIVE: To detect the relationship between ApoE gene polymorphism and coronary heart disease(CHD), arteriosclerotic cerebral infarction(ACI). METHODS: Exon 4 of ApoE gene was analyzed in normal group(87 cases), CHD group(78 cases) and ACI group(55 cases) by a combination of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct AgNO(3) staining technique. RESULTS: Between the control group and CHD group, ACI group, chi(2) test showed no significant difference in genotype of E3/E3 (P>0.5, P>0.1, respectively); while mu test showed no significant difference in allele epsilon(2)(P>0.25, P>0.1, respectively), epsilon(4)(P>0.1, P>0.25, respectively) of ApoE. CONCLUSION: No relationship between ApoE gene polymorphism and CHD and ACI was noted in this study.

Apolipoproteins E↗
PubMed1999

[Four cases of cancer of unknown primary site that manifested as mediastinal metastatic lesions].

We encountered 4 patients with cancers of unknown primary sites that were manifested by mediastinal lesions. Patient 1 was a 58-year-old man with enlarged superior mediastinal lymph nodes. An exploratory thoracotomy yielded a diagnosis of lymph node metastasis of poorly differentiated adenocarcinoma. The patient was treated with chemotherapy and radiation therapy. Patient 2 was a 68-year-old man with a tumor in the right superior mediastinum. A total resection of the tumor was performed through a thoracotomy. The diagnosis was lymph node metastasis of squamous cell carcinoma, and treatment consisted of irradiation. A tumor shadow in the right upper lobe appeared 14 months after the thoracotomy, and was considered to be a primary lesion requiring a right pneumonectomy. The patient died of hepatic metastasis 6 months after the second operation. Patient 3 was a 59-year-old man with mediastinal and hilar lymph node swelling. Mediastinoscopic findings resulted in a diagnosis of squamous cell carcinoma. Because of the patient's insistence, only radiation therapy was performed. Patient 4 was a 65-year-old woman with a tumor in the right superior mediastinum who underwent a median sternotomy for total resection of the tumor. The pathological findings were strongly suggestive of metastasis of clear cell carcinoma. Patients 1, 3, and 4 were alive 33, 24, and 51 months, respectively, after their initial operation, without detectable primary sites. Patient 2 was considered to have had T 0 N 2 lung cancer.

Adenocarcinoma↗
PubMed1999

[Changes in cardiac renin-angiotensin system after severe burn injury in rats].

OBJECTIVE: To observe changes in cardiac renin-angiotensin and its effect on sarcoplasmic reticulum(SR) calcium transport function, and investigate the mechanism underlying cardiac dysfunction in early postburn stage. METHODS: Rats were divided into three groups: control group (n = 8, without burns), burn group (n = 40, 30% TBSA full-thickness burns), and treatment group (n = 40, gavage Lisinopril for 3 days before 30% TBSA burns). The left ventricular(LV) contractile function was measured at 3, 8, 24 hours postburn. Angiotensin converting enzyme(ACE) activities, the contents of angiotensin II (AII) and calcium in myocardium were also measured. In addition, Ca(2+)-ATPase activities and calcium transport function in SR were determined. RESULTS: The maximal rates of LV pressure rise (+/- dp/dtmax) and fall (-dp/dtmax) in burn group were significantly lower than that in control group. The ACE activities, AII levels, as well as calcium contents in myocardium increased markedly in burn group. Ca(2+)-ATPase activities and Ca2+ uptake function in SR decreased significantly in burn group. After treatment with ACE inhibitor-Lisinopril, the ACE activities, AII levels and calcium contents were significantly decreased compared to the burn group. Meanwhile, Ca(2+)-ATPase activities, calcium uptake function and LV contractile function decreased markedly. CONCLUSION: The cardiac renin-angiotensin system is activated rapidly after severe burns and inhibits the calcium transport function which may play an important role in cardiac contractile dysfunction following burns.

Angiotensin II↗
PubMed1999

Diagnosis and treatment of splanchnic artery aneurysms: a report of 57 cases.

OBJECTIVE: To evaluate the diagnosis and treatment of splanchnic artery aneurysms. METHODS: A retrospective study of our case records from 1957 to 1997 was carried out. Fifty-seven patients with splanchnic artery aneurysms were involved in this study with 62 aneurysms, including hepatic aneurysm (14 patients), gastric and pancreaticoduodenal aneurysm (13), splenic aneurysm (14), renal aneurysm (6), superior mesenteric aneurysm (3), inferior mesenteric aneurysm (1), truncus coeliacus (3) and epiploic arterial aneurysm (3). Among them, 5 patients had multiple aneurysms; 29 had massive bleeding of spontaneous rupture into the biliary tract (14 patients), the upper gastrointestinal tract (10), and the peritoneal and retroperitoneal cavity (5). RESULTS: Preoperative diagnosis was confirmed by arteriography in 37 patients, digital subtraction angiography (DSA) in 2, and magnetic resonance angiography (MRA) in 2. Among the 46 patients who underwent surgical intervention, 9 died. Splanchnic arterial embolotherapy was performed in 6 patients. CONCLUSION: Splanchnic artery aneurysms have a potential for rupture with life-threatening hemorrhage. Clinical assessment of these lesions before operation is very difficult. The most valuable examination is selective arteriography of the splanchnic artery (including DSA). Surgical treatment is a safe and effective procedure. Embolic therapy may be the method of choice for selected splanchnic artery aneurysms. Prognosis of this disorder depends on the anatomic location of aneurysms, primary disease and general condition of patients.

Adolescent↗
PubMed1999

[The value of MR cholangiopancreatograghy in diagnosis of obstructive jaundice].

OBJECTIVE: To evaluate the diagnostic value of MRCP in finding positions and causes of obstructive jaundice. METHODS: Fourty-two patients with obstructive jaundice received MRCP examination. All patients were finally onfirmed operatively. RESULTS: The correct diagnostic rate of finding obstructive positions in MRCP was 100% and the correct rate of finding obstructive causes 78.57%. MRCP combined with MRI raised the accuracy of diagnosis of obstructive causes. (90.48%). All pathogenic changes have their own characteristics. CONCLUSIONS: MRCP in diagnosing obstructive jaundice is quite effective and safe because of its clear pictures without use of contrast medium and no complications.

Adult↗
PubMed1999

[Studies on apoptosis of human lung adenocarcinoma cells induced by oltipraz].

OBJECTIVE: To study whether oltipraz can induce apoptosis of human lung adenocarcinoma (GLC-82) cells and its possible mechanism. METHODS: Light microscopy, DNA electrophoresis, flow cytometry and video time-lapse monitoring were used to observe apoptosis of GLC-82 induced by oltipraz. RESULTS: GLC-82 cells treated with oltipraz underwent the arrest of cell mitosis at metaphase, higher percentage of G(2)/M and peak of apoptosis were found, and cell body shrunk, nuclear chromosome condensed or fragmented and nuclear DNA fragment displayed "laden" bands in apoptic cells. Apoptosis of GLC-82 induced by oltipraz was more obvious at a concentration of 120 microg/ml. CONCLUSION: Oltipraz could induce apoptosis of GLC-82 at certain concentrations, which associated closely with the arrest of mitotic cycle.

Adenocarcinoma↗
PubMed1999

[A study on factors contributing to intelligence in 857 children].

OBJECTIVE: To study the main environmental factors affecting intelligence of children. METHODS: Intelligence quotients (IQ) were examined in 857 pupils of grades 1 to 6 in a primary school and categorized into four different classes. Data of relevant environmental factors were collected with questionnaires. Uni-variate and multivariate logistic regression analyses were performed to identify the factors influencing their IQ. RESULTS: There were 27 factors with statistical significance in uni-variable analysis. And, then they were analyzed with stepwise logistic regression method. Six variables, i.e., parents' education level, breast feeding during infancy, early education at home, nutritional status before three years old, single parent family and average scores at school, enter the regression model finally. CONCLUSION: Intelligence development in children was affected by a lot of factors, and good acquired environmental factors, especially their early nutrition, family background and education, would benefit for their intelligent development and improvement of their intelligent ability in children.

Child↗
PubMed1999

[Studies on the preparation and characters of anti-AFB1 antibody from the yolk of laying hens].

AFB1O-BSA conjugates were injected into four laying hens (A, B, C and D). The yolk anti-AFB1 antibodies A,C and D produced were obviously increased after 90 days of the first injection, and reached the peak after 135 days, and started dropping after 165 days. The indirect ELISA titer of yolk antibodies A,C and D were 1:8000, 1:6000 and 1:6000 respectively. The specificity of the antibody A was good, but a cross-reaction with AFB2, AFG1, AFG2, with an exception of AFM1, was found. The sensitivities of AFB1, AFB2, AFG1 and AFG2 were 6, 25, 125 and 2495 micrograms/L respectively.

Aflatoxin B1↗