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Biomedical subjects

L Yan

Publications and source records attributed to L Yan.

At least 145 records · Page 8Linked to original sources
PubMed1999

A study of early pregnancy factor activity in the sera of women with trophoblastic tumor.

PROBLEM: To detect whether or not the early pregnancy factor (EPF)-like activity, or chaperonin 10, could be in the sera of patients with trophoblastic tumor in order to find another more efficient means to diagnose this kind of tumor. METHOD OF STUDY: The rosette inhibition assay was used to detect EPF-like activity in 216 sera, collected from patients with gestational trophoblastic tumor, including 47 sera of patients with choriocarcinoma, 68 sera of patients bearing invasive mole, and 101 sera of patients with vesicular mole. RESULTS: The accuracy of diagnosing malignant trophoblastic tumor by detecting EPF-like activity is 91.3% (105/115), with a false positive rate of 14.58% and a false negative rate of 4.8% by this method. Furthermore, the rosette inhibition titer (RIT) values have significant difference (P < 0.001) between the sera in patients with malignant trophoblastic tumor before treatment and those after treatment. CONCLUSIONS: This study demonstrated that diagnosis of malignant trophoblastic tumor could be made with an accuracy of 91.3% by detecting EPF-like activity and that EPF-like activity could be used as an indicator to distinguish benign from malignant trophoblastic tumor.

Adult↗
PubMed1999

Terminal differentiation in epithelia: the Hensin pathway in intercalated cells.

The intercalated cell of the collecting tubule exists in a spectrum of types. The alpha form secretes acid by an apical H+-ATPase and a basolateral CI:HCO3 exchanger, which is an alternatively spliced form of the red cell band 3 (kAE1), and the beta form secretes HCO3 by having these transporters on the reverse membranes. In a clonal cell line of the beta form, we found that seeding density causes conversion of beta cells to the alpha form. A new protein, termed hensin, was deposited in the extracellular matrix (ECM) of high-density cells, which, on purification, reversed the polarity of the transporters. Hensin also induced the expression of the microvillar protein villin and caused the appearance of the apical terminal web proteins, cytokeratin 19 and actin; all of which led to the development of an exuberant microvillar structure. In addition, hensin caused the beta cells to assume a columnar shape. All of these studies show that the conversion of polarity in the intercalated cell, at least in vitro, represents terminal differentiation and that hensin is the first protein in a new pathway that mediates this process. Hensin, DMBT1, CRP-ductin, and ebnerin are alternately spliced products from a single gene located in human chromosome 10q25-26, a region often deleted in several cancers, especially malignant gliomas. Hensin is expressed in many epithelial cell types and it is possible that it plays a similarly important role in the differentiation of these epithelia as well.

Adaptation, Physiological↗
PubMed1999

Cyclic GMP and cyclic AMP induced changes in control and hypertrophic cardiac myocyte function interact through cyclic GMP affected cyclic-AMP phosphodiesterases.

We tested the hypothesis that the negative functional effects of cyclic GMP (cGMP) would be greater after increasing cyclic AMP (cAMP), because of the action of cGMP-affected cAMP phosphodiesterases in cardiac myocytes and that this effect would be altered in left ventricular hypertrophy (LVH) produced by aortic valve plication. Myocyte shortening data were collected using a video edge detector, and O2 consumption was measured by O2 electrodes during stimulation (5 ms, 1 Hz, in 2 mM Ca2+) from control (n = 7) and LVH (n = 7) dog ventricular myocytes. cAMP and cGMP were determined by a competitive binding assay. cAMP was increased by forskolin and milrinone (10(-6) M). cGMP was increased with zaprinast and decreased by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxilin-1-one (ODQ) both at 10(-6) and 10(-4) M, with and without forskolin or forskolin + milrinone. Zaprinast significantly decreased percent shortening in control (9 +/- 1 to 7 +/- 1%) and LVH (10 +/- 1 to 7 +/- 1%) myocytes. It increased cGMP in control (36 +/- 5 to 52 +/- 7 fmol/10(5) myocytes) and from the significantly higher baseline value in LVH (71 +/- 12 to 104 +/- 18 fmol/10(5) myocytes). ODQ increased myocyte function and decreased cGMP levels in control and LVH myocytes. Forskolin + milrinone increased cAMP levels in control (6 +/- 1 to 15 +/- 2 pmol/10(5) myocytes) and LVH (8 +/- 1 to 18 +/- 2 pmol/10(5) myocytes) myocytes, as did forskolin alone. They also significantly increased percent shortening. There were significant negative functional effects of zaprinast after forskolin + milrinone in control (15 +/- 2 to 9 +/- 1%), which were greater than zaprinast alone, and LVH (12 +/- 1 to 9 +/- 1%). This was associated with an increase in cGMP and a reduction in the increased cAMP induced by forskolin or milrinone. ODQ did not further increase function after forskolin or milrinone in control myocytes, despite lowering cGMP. However, it prevented the forskolin and milrinone induced increase in cAMP. In hypertrophy, ODQ lowered cGMP and increased function after forskolin. ODQ did not affect cAMP after forskolin and milrinone in LVH. Thus, the level of cGMP was inversely correlated with myocyte function. When cAMP levels were elevated, cGMP was still inversely correlated with myocyte function. This was, in part, related to alterations in cAMP. The interaction between cGMP and cAMP was altered in LVH myocytes.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1999

Ranitidine bismuth citrate and clarithromycin, alone or in combination, for eradication of Helicobacter mustelae infection in ferrets.

OBJECTIVE: To determine whether ranitidine bismuth citrate, clarithromycin, or a combination of ranitidine bismuth citrate and clarithromycin would be efficacious in eradication of Helicobacter mustelae infection in ferrets. ANIMALS: 60 seven-month-old ferrets. PROCEDURE: To determine dosages of clarithromycin and ranitidine bismuth citrate that would suppress growth of, but not eradicate infection with, H mustelae, ferrets (n = 6/group) were treated p.o. with clarithromycin or ranitidine bismuth citrate at various dosages. Efficacy of treatment was then determined by treating ferrets with clarithromycin alone, ranitidine bismuth citrate alone, or clarithromycin and ranitidine bismuth citrate. Gastric biopsy specimens were obtained before, during, and at various times after treatment and submitted for quantitative bacterial culture and histologic evaluation. Minimum concentrations of clarithromycin that inhibited 90% of the growth of isolates obtained before and after treatment were determined. RESULTS: Dosages of clarithromycin and ranitidine bismuth citrate that suppressed growth of H mustelae were 12.5 and 24 mg/kg of body weight, p.o., every 8 hours, respectively. Infection was not eradicated in ferrets treated with ranitidine bismuth citrate alone but was eradicated in all 6 ferrets treated with clarithromycin and ranitidine bismuth citrate and in 4 of 6 treated with clarithromycin alone. A decrease in susceptibility to clarithromycin was detected for H mustelae isolates obtained after treatment. Mild or moderate antral gastritis was observed even in ferrets from which infection was eradicated. CONCLUSIONS AND CLINICAL RELEVANCE: A combination of ranitidine bismuth citrate and clarithromycin was efficacious in eradicating H mustelae infection from ferrets.

Animals↗
PubMed1999

[Intrapulmonary expression of tumor necrosis factor alpha mRNA and its significance in rats with acute pancreatitis].

It is thought that tumor necrosis factor (TNF) plays an important role in pathogenesis of acute lung injury or ARDS. So we want to get insight into the relationship between intrapulmonary expression of TNF-alpha gene and lung injury during acute necrotizing pancreatitis (ANP). In our study, acute edematous pancreatitis (AEP) and ANP were induced in rats by caerulein and sodium taurocholate respectively. After acute pancreatitis was induced, serum TNF-alpha was assessed by ELISA assay while endotoxin was assessed by limulus lysate test. Intrapulmonary expression of TNF-alpha mRNA was detected by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) technique. Moreover, content of pulmonary lesion was investigated and graded with microscope. It was found that TNF-alpha concentration in blood elevated markedly after acute pancreatitis was induced, especially in ANP group. Results of RT-PCR revealed that no TNF-alpha mRNA could be detected in lung tissue from those rats undergoing sham-operation, but marked expression appeared 1 hour after AEP or ANP was induced. Upregulation of expression of TNF-alpha gene in the early 3 hours was similar in the two groups with pancreatitis, and since then expression of TNF-alpha mRNA in ANP group was stronger than that in AEP group. Serum endotoxin increased significantly 6 hours after ANP was induced, with a higher level at 12 hour. However, there was no marked change of endotoxin level in AEP group and control group. It is noted that intrapulmonary expression of TNF-alpha gene in ANP group reached its peak as soon as serum endotoxin increased markedly. Lung damage in ANP group was more serious than that in AEP group significantly. Score of lung injury correlated well with TNF-alpha concentration in blood and expression of its gene in lung tissue in either AEP group or ANP group, as well as with serum endotoxin in ANP group. So overwhelm expression of some harmful cytokines like TNF-alpha in lung tissue may be the main cause of lung injury during acute necrotizing pancreatitis, and stimulation of endotoxiemia can at least partly explain the upregulation of expression of TNF-alpha gene.

Animals↗
PubMed1999

[Antipyretic action of dexamethasone on egtazic acid-induced fever in rabbits].

The purpose of the present study was to investigate whether the antipyretic effect of dexamethasone (DEX) delivered by intravenous injection (i.v.) on intracerebroventricularly (icv) administered egtazic acid-induced febrile response is relevant to the changes in cytosolic free calcium concentration of the hypothalamus. The colon temperatures were measured by a thermistor and the cytosolic free calcium concentration ([Ca2+]i) in dissociated brain cells was measured by Fura 2-AM. The results demonstrated that the pyretic action of egtazic acid (0.6 mumol, icv) was markedly inhibited by DEX (5 mg/kg, i.v.), but DEX (60-120 mumol/L) did't affect [Ca2+]i in dissociated hypothalamus cells. Actinomycin D, which interferes with gene transcription (3 nmol, icv), completely abolished the antipyretic action of DEX on egtazic acid-induced fever. These findings suggest that the antipyretic action of DEX on egtazic acid-induced fever is related to the activation of certain gene expression in the brain, but not to the changes of transmembrane calcium ion current in hypothalamus neurons.

Analgesics, Non-Narcotic↗
PubMed1999

[Effects of calcium overload in the conversion of acute edematous pancreatitis to necrotizing pancreatitis in rats].

OBJECTIVE: To investigate the potential of pancreatic acinar cell calcium overload in the conversion of acute edematous pancreatitis (AEP) to necrotizing pancreatitis (ANP). METHODS: Ninety-six Sprague-Dawley rats were randomized in three experimental groups. Sham-operated control (Group I) AEP (Group II) was induced by pancreatic duct ligation and intravenous injection of bombesin (100 micrograms/kg) and secretin (10 micrograms/kg). ANP (Group III) was induced same as group II but with a large dose of dextran 110,000(500 mg/kg) intravenously. Pancreatic acinar cell Ca2+ overload was studied using fluorescent probe Fura2. Cytosolic free Ca2+ concentration ([Ca2+]i) in isolated pancreatic acinar cells and Ca(2+)-ATPase activity in pancreatic cell plasma membranes were determined 1, 3, 6, 9 h respectively after treatment. RESULTS: The results showed that pancreatic acinar cell [Ca2+]i was elevated at 1 h[(213 +/- 19) nmol/L, P < 0.05] and increased to (464 +/- 29) nmol/L at 6 h(P < 0.05) in rats with ANP, pancreatic cell plasma membrane Ca(2+)-ATPase activity decreased significantly from (29.8 +/- 0.4) nmol.min-1.mgp-1 at 1 h to (18.6 +/- 0.5) nmol.min-1.mgp-1 at 9 h in rats with ANP (P < 0.05). CONCLUSIONS: In ischemia-induced conversion of AEP to ANP, there exists Ca2+ overload in the pancreatic acinar cells. The decreased pancreatic cell plasma membrane Ca(2+)-ATPase activity may be an important reason for acinar cell Ca2+ overload in the development of acute pancreatitis.

Animals↗
PubMed1999

Induction of islet transplantation tolerance with anti-CD4, anti-CD8 immunotoxins and donor soluble antigen.

OBJECTIVE: To induce islet grafting tolerance by intravenous injection of anti-CD4, anti-CD8 immunotoxins and donor soluble antigen. METHODS: Fourteen days or 7 days prior to transplantation, the immunotoxin of anti-CD4, anti-CD8 200 micrograms respectively, and donor soluble antigen 500 micrograms were intravenously injected and then 500 donor islets were transplanted under the left renal subcapsular space of diabetes recipients (Sprague-Dawley rats). RESULTS: The islet grafting survival time for those recipients pretreated with immunotoxin and donor soluble antigen was > 60 days (P < 0.01). The immunotoxins, donor soluble antigen treatment alone might only slightly prolong the grafting survival time. CONCLUSION: The anti-CD4, anti-CD8 immunotoxins jointly used with donor soluble antigen can induce donor specific immunotolerance.

Animals↗
PubMed1999

[The feature of pancreatic microcirculatory impairment in caerulein induced acute pancreatitis].

OBJECTIVE: To study the feature of pancreatic microcirculatory impairment in caerulein-induced acute pancreatitis. METHODS: The AP model of subcutaneous injection of caerulein was studied by intravital fluorescence microscopy of erythrocytes labeled by FITC (FITC-RBC) and by scanning electron microscopy of vascular corrosion casts and light microscopy of Chinese ink-injected/cleared tissues. RESULTS: Animals treated with caerulein showed hyper-amylases. Contractions of intralobular arteriolar sphincter, presence of vacuoles in all the layers of sphincter, gross irregularity in capillary network of acini were observed in caerulein-induced groups. The decrease of pancreatic capillary blood flow (P < 0.01), reduction of functional capillary density, and irregular intermittent perfusion (P < 0.05) were found. CONCLUSIONS: Impairment and contraction of pancreatic intralobular arteriolar sphincter are the initial microcirculatory lesions in the early phase of acute pancreatitis induced by Caerulein, and play a key role in the pancreatic ischemia and pancreatic microvascular failure in acute pancreatitis.

Acute Disease↗
PubMed1999

[Co-transplantation of islet and allogeneic testicular cell induced immune privilege].

OBJECTIVE: To induce islet allograft long-term survival through co-transplantation islet with sertoli cell. METHODS: Testicular sertoli cell was prepared by digestion of collagenase, trypsin and Dnase, and cultured for 48 hours. Purified donor (Wistar rat) islet was co-transplanted with allergic sertoli cell, in the absence of systemic immunosuppression. TUNEL (terminal deoxynucleotidyl transferase-mediated X-dUTP nick end labeling) was used to label the apoptosis of lymphocytes surrounding the islet graft. The SABC method was used to label the expression of Fas ligand in co-transplantation. RESULTS: Islet co-transplantation with 1 x 10(7) sertoli cell reversed the diabetic state for more than 60 days in 100% (6/6) of the chemically diabetic SD recipients. Similar grafts consisting of islet alone or islet plus 1 x 10(5)-sertoli cell survived only for 5 - 6 days. Apoptosis of the lymphocytes surrounding the islet was quite clear. CONCLUSIONS: Co-transplantation islet with FasL(+) sertoli cell induces local immune privilege and allows long-term graft survival without systemic immunosuppression.

Animals↗
PubMed1999

[Clinical protocols for the treatment of severe acute pancreatitis].

OBJECTIVE: To set up principles for the treatment of severe acute pancreatitis (SAP). METHODS: The therapeutic principles and results of SAP in three periods were analyzed. Period I (1980 - 1990) was characterized by early surgical intervention supplemented with integrated traditional and western medical therapy, period II (1991 - 1993) by integrated traditional and western medical therapy supplemented with surgery for early complications, and period III (1994 - 1997) by integrated traditional and western medical therapy supplemented with surgery for local infectious complications only. RESULTS: Because of the improvement of intensive care, the operation rates kept declining in the three periods. They were 77.59%, 54.55% and 29.55% with a mortality rate of 40.52%, 17.17% and 11.36%, respectively. CONCLUSIONS: Integrated traditional and western medicine has been effective in most SAP patients, and surgery is indicated only for late complications such as necrotizing infection. Early surgery should be restricted.

Adolescent↗
PubMed1999

[Intermittent-pulse treatment of onychomycosis with orally administered itraconazole].

Fifty-four patients received an intermittent regimen of itraconazole (26 of them were finger onychomycosis and 28 toe onychomycosis) and were followed-up for nine months. The result showed that the clinical cure rate of fingernails was 88.5% and the mycologic cure rate was 96.4%, while the clinical cure rate of toes was 82.1% and the mycologic cure rate was 96.4%. Few adverse events were observed by 7.4%, just like nausea, gastric discomfort etc. It suggests that the pulse administration system is highly effective and has a few side-effects.

Adolescent↗
PubMed1999

[Expression of bcl-2, bax and p53 protein in the basal cell carcinoma].

The expression of bcl-2, bax and p53 protein was studied in the basal cell carcinoma with 32 patients by immunohistochemical method. The results showed that bcl-2 protein was positive in 26 patients (81.2%), bax protein was positive in 9 patients(28.1%), and p53 protein was positive in 13 patients (40.6%); there is a negative correlation between the expression of bcl-2 and bax protein(P < 0.05). These findings suggest that apoptosis is suppressed which might cause the production of basal cell carcinoma.

Aged↗
PubMed1999

[Study on regulators of the cell cycle in cutaneous squamous cell carcinoma].

In order to investigate the relationship between the regulators of cell cycle and cutaneous squamous cell carcinoma(SCC), we used an immunohistochemical staining technique to examine the expression of cyclin D1, p16 and Rb in the paraffin embedded skin cancer tissues of 30 patients with SCC. The positive percentage of cyclin D1, CDK4, p16 and Rb was 66.7%, 53.3%, 33.3%, and 36.7%, respectively. The overexpression of cyclin D1 and CDK4 could be observed frequently in low grade of differentiated cells, especially in marginal cells of the cancer nest. The results indicate that the aberrant expression of positive and negative regulators of the cell cycle may be involved in the carcinogenesis and evolution of SCC.

Carcinoma, Squamous Cell↗
PubMed1999

[Applied anatomy of the paraumbilical flap with the lateral anterior branch of the thoracic nerve].

OBJECTIVE: To provide the anatomical basis for the free paraumbilical flap with sensory nerve. METHODS: The morphology, branch and distribution of the inferior epigastric artery and inferior intercostal nerve were dissected and measured in 20 adult cadaver specimens. RESULTS: The diameter of inferior epigastric artery at the original point was (2.3 +/- 0.3) mm, and that of its accompanying vein was (3.6 +/- 0.4) mm. The anterial branch of inferior intercostal nerves transversed through their corresponding intercostal spaces of axilla anterior line and ran out of the superficial fascia at the midclavicular line. The lateral anterior branch of the eighth to tenth intercostal nerves ran out of superficial fascia in the range of 0-7 cm above umbilicus and innervated the paraumbilical flap. CONCLUSION: It is possible to design sensory paraumbilical flap with the lateral anterior branch of the eighth to tenth intercostal nerve.

Adult↗
PubMed1999

[A clinical study on systemic inflammatory response syndrome and multiple organ dysfunction syndrome in patients with abdominal surgical emergency].

In order to analyze the development from systemic inflammatory response syndrome(SIRS) to multiple organ dysfunction syndrome (MODS) and probe the therapeutic strategies, the authors studied retrospectively the clinical data of SIRS and MODS in 1374 patients with abdominal surgical emergency. The results showed that on admission the morbidity of SIRS was 32.5%, afterwards the morbidity of MODS was 6.4%, and the mortality of the patients with SIRS was 4.8%. After 48 hours' therapy, MODS developed in 33.0% of the SIRS cases. Of all the 1374 patients, 40 developed MODS(2.9%) and 27 died (67.5%). The authors point out that the outcome of the patients with abdominal surgical emergency can be improved on condition that SIRS is early diagnosed, the cause of SIRS after 48 hours of therapy is well defined, and the body inflammatory response is properly regulated.

Abdomen, Acute↗