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Biomedical subjects

A Sun

Publications and source records attributed to A Sun.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Induction and validation of arterial calcium overload in rats].

OBJECTIVE: To induce arterial calcium overload (ACO) in rats and analyze its features. METHODS: Arterial calcium content and intracellular calcium content were determined by atomic absorption spectrometer and electron probe microanalysis, respectively. The morphological changes of endothelial cells and vascular smooth muscle cells were studied with scanning and transmission electron microscopes. DNA contents and its mass distribution were determined by DNA imaging analysis. Arterial collagen and elastin contents were determined biochemically. RESULTS: Seven days after the induction of ACO with selected regimen, massive calcium was found accumulating in the arterial wall, including the cytoplasm and mitochondrion of the medial smooth muscle cells, indicating both extracellular and intracellular calcium overload. Degeneration of aortic endothelial cells was found at the early stage of ACO under scanning and transmission electron microscope. At the late time of ACO, significant proliferation and sclerotic reactions of arteries occurred, including the proliferation of smooth muscle cells, matrix remodeling, and damage of elastic structure. The average DNA content per smooth muscle cell was elevated, and more cells entered the S phase of proliferating cycle since day 7. On the other hand, total collagen content of aorta was increased 7 days after induction of ACO, and rose continuously at day 14 (P < 0.05). Functional studies showed that arterial elasticity was significantly impaired. CONCLUSION: Our method could induce ACO/constantly in rats, and the ACO model shares the similarities with the characterization of human arteriosclerosis on many aspects.

Animals↗
PubMed1999

[Synergistic interaction between Ys-96, a bisbenzylisoquinoline compound derived from Stephania tetrandra, and adriamycin or vincristine against human cancer cell lines in vitro].

OBJECTIVE: To study in vitro the anticancer interaction between Ys-96, a bisbenzylisoquinoline compound derived from Stephania tetrandra, and adriamycin or vincristine against human cancer cell lines. METHOD: Using human breast cancer cell MCF-7 and its adriamycin-resistant cell line MCF-7/Adr, and human nasopharyngeal cancer cell KB and its vincristine-resistant cell line KBv200 in an in vitro system, anticancer interaction between Ys-96 and adriamycin or vincristine was evaluated with a method reported by Berenbaum. RESULT: The SFIC values (sum of fractional inhibitory concentration) of the combinations with 3 different ratios between Ys-96 and adriamycin or vincristine were markedly less than 1.0, and the shapes of all the isobologram curves were concave. CONCLUSION: The synergistic interaction between Ys-96 and adriamycin or vincristine against the above human cancer cell lines was positively observed in vitro.

Antineoplastic Agents, Phytogenic↗
PubMed1999

[Determination of the aconitine alkaloids in traditional Chinese medicine chuanwu and caowu by high performance capillary electrophoresis(HPCE)].

A simple and rapid method for the simultaneous assay of three aconitine alkaloids (mesaconitine (MA), hypaconitine (HA) and aconitine (A) in the traditional Chinese medicines, Chuanwu and Caowu, by high performance capillary electrophoresis has been established, using tetracaine as an internal standard. The experimental conditions were as follows, the electrophoretic medium was composed of V[70 mmol/L Tris-borate (pH 8.49)]: V(methanol) = 60:40, uncoated capillary used was 50 cm x 50 microns i.d. and detection was carried out with a UV monitor at 235 nm. The separation was achieved by optimizing the cartridge temperature, the applied voltage, and the pH as well as the concentration of the buffer, and organic modifier. The calibration curve showed a good linearity in the mass concentration range of 0.0115-0.8330 g/L (r = 0.9996) for MA, 0.0089-0.6440 g/L (r = 0.9997) for HA, and 0.0083-0.6000 g/L(r = 0.9997) for A. The recoveries ranged from 93.0% to 104.0% with relative standard deviations from 0.68% to 1.7%. The total time for separation and determination was within 23 min. By means of this method, three aconitine alkaloids in Chuanwu and Caowu have been determined.

Aconitine↗
PubMed1998

Tardive dyskinesia and serum iron indices.

BACKGROUND: This study was undertaken to evaluate whether peripheral (serum) markers of iron status are associated with severity of the choreoathetoid movements seen in tardive dyskinesia (TD). METHODS: Serum iron indices (ferritin, iron, and total iron binding capacity) and fluphenazine levels were measured in a group of 30 male DSM-III diagnosed schizophrenic patients chronically treated with fluphenazine decanoate. The severity of choreoathetoid movements was assessed with the Abnormal Involuntary Movement Scale (AIMS), and akathisia was assessed with the Barnes scale. RESULTS: A significant positive correlation was observed between AIMS scores and serum ferritin. This relationship remained significant after controlling for age and plasma fluphenazine levels. No significant correlations were observed between serum iron or total iron binding capacity and choreoathetoid movement ratings. There were no significant associations between serum iron indices and akathisia ratings. CONCLUSIONS: The data suggest that choreoathetoid movements are associated with serum ferritin levels in chronically medicated male schizophrenic patients. This relationship does not seem to be caused by an association of these variable with age or plasma fluphenazine levels. In addition, the relationship seems to be specific, since other iron indices and another extrapyramidal side effect (akathisia) do not demonstrate a similar relationship. In view of reports that antipsychotic medications change normal iron metabolism and increase iron uptake into the brain, the current results could be interpreted to suggest that serum ferritin levels may be a risk factor for TD in patients treated with "classic" antipsychotic medications.

Adult↗
PubMed1998

Effects of molecular structures on the olfactory responses of phospholipid membranes to four alcohols.

In order to understand the relationship between phospholipid molecular structures and their olfactory responses to odorants, we designed and synthesized four phosphatidylcholine analogues with different long hydrocarbon (CH) chains and selected three natural phospholipids with different head-groups. By using interdigital electrodes (IEs) as olfactory sensors (OSs), we measured the responses of the IEs coated with these seven different lipid membranes to four alcohol vapors in a gas flow system. The IEs voltage changes were recorded and the voltage-relative saturate vapor pressure (V-P/P degree) curves were also plotted. It was found that with a methyl (-CH3) placed at the C-8 position in the 18-carbon chain, the olfactory responses could be improved about ten times and with conjugated double bonds (C-C) in the long chains, the sensitivity could be increased by 3-4 orders of magnitude. As to head-groups, choline is preferred over ethanolamine and serine in phospholipid structures in terms of high olfactory sensitivity. These results are expected to be useful in further designing and manufacturing lipid-mimicking OSs.

1-Propanol↗
PubMed1998

Outcome in breast cancer managed without an initial axillary lymph node dissection.

PURPOSE: The role of an elective axillary lymph node dissection (AxLND) in the initial management of patients with early stage breast cancer has recently become controversial. The objective of this current study is to review the reasons as to why patients from a single institution were managed without an initial AxLND and their outcome in terms of survival and recurrence rates. MATERIALS AND METHODS: A retrospective analysis was conducted on 126 women referred to the Princess Margaret Hospital with the diagnosis of breast cancer who did not undergo an initial AxLND. RESULTS: The median age of this population was 69 years, with the vast majority (93%) being post-menopausal. Fifty-seven patients had T1 tumors and the remainder had T2-3 tumors. Adjuvant radiation therapy to the breast was administered to 65 patients and systemic adjuvant treatment was administered to 24 patients. In approximately one-third of these cases, the reasons cited for not performing an AxLND were related to the patient's age, a medical contraindication, or the patient's choice. The 5-year actuarial cause-specific survival was 92%; the local breast relapse-free rate (RFR) was 85% and the axillary RFR was 86%. No patients in this study experienced debilitating symptoms from their axillary disease. Only 16 patients underwent a subsequent AxLND, with the lymph nodes being pathologically uninvolved in six of these patients. CONCLUSION: This study supports the concept that. in selected patients, adopting an approach of a delayed AxLND does not appear to compromise the patients' outcome, with only 13% of patients requiring a subsequent AxLND.

Actuarial Analysis↗
PubMed1998

Oxygenation predicts radiation response and survival in patients with cervix cancer.

BACKGROUND AND PURPOSE: Hypoxia appears to be an important factor in predicting tumor relapse following radiation therapy. This study measured oxygenation prior to treatment in patients with cervix cancer using a polarographic oxygen electrode to determine if oxygenation was an important prognostic factor with regard to tumor control and survival. MATERIALS AND METHODS: Between May 1994 and June 1997, 74 eligible patients with cervix cancer were entered into an ongoing prospective study of tumor oxygenation prior to primary radiation therapy. All patients were evaluated with an Eppendorf oxygen electrode during examination under anesthesia. Oxygenation data are presented as the hypoxic proportion, defined as the percentage of pO2 readings of <5 mm Hg (abbreviated as HP5). RESULTS: The HP5 ranged from 2 to 99% with a median of 52%. With a median follow-up of 1.2 years, the disease-free survival (DFS) rate was 69% for patients with HP5 of < or =50% compared with 34% for those with HP5 of >50% (log-rank P = 0.02). Tumor size above and below the median of 5 cm was also significantly related to DFS (P = 0.0003) and patients with bulky hypoxic tumors had a significantly lower DFS (12% at 2 years) than either bulky oxygenated or non-bulky oxygenated or hypoxic tumors (65%, P = 0.0001). CONCLUSIONS: Hypoxia and tumor size are significant adverse prognostic factors in a univariate analysis of disease-free survival in patients with cervix cancer. A high risk group of patients with bulky hypoxic tumors have a significantly higher probability of relapse and death.

Adenocarcinoma↗
PubMed1998

Preliminary evidence for an association of Epstein-Barr virus with pre-ulcerative oral lesions in patients with recurrent aphthous ulcers or Behçet's disease.

In this study we used the polymerase chain reaction (PCR), slot blot and Southern blot hybridization, direct sequencing and in situ hybridization (ISH) to show the possible presence of EBV-DNA in pre-ulcerative oral aphthous lesions of patients with recurrent aphthous ulcers (RAU) or Behçet's disease (BD). For this purpose, formalin-fixed biopsy specimens were obtained from 13 pre-ulcerative oral aphthous lesions of nine RAU and four BD patients. Five specimens of normal oral mucosa (NOM) from five normal control subjects and 10 specimens of oral erosive or ulcerative lesions from 10 patients with erosive lichen planus (ELP) were also included. EBV-DNA was detected by PCR in 5 of the 13 (38.5%) pre-ulcerative oral aphthous lesions, two from RAU patients and three from BD patients. However, no EBV-DNA was demonstrated in five NOM specimens from normal control subjects and in 10 specimens of oral lesions from ELP patients. EBV-DNA was also demonstrated in patients' peripheral blood lymphocytes and/or plasma, suggesting that the lymphocytes may be the reservoir of latent EBV infection and there is EBV shedding in the plasma. EBV-DNA was detected by ISH in only one PCR-positive case; the reaction product was found to deposit on the nuclei of some of the epithelial cells and lymphocytes. By immunohistochemistry, expression of Epstein-Barr nuclear antigen and EBV/C3d receptors was also noted in some of the epithelial cells and lymphocytes in this ISH-positive case. Therefore, we suggest that the epithelial cells of pre-ulcerative oral aphthous lesions may be infected by EBV through EBV-infected lymphocytes; also, the cytotoxic T lymphocyte-induced lysis of the EBV-infected epithelial cells, but not the virus-induced cytolysis, may be the main mechanism causing oral ulcer formation. Our data provide preliminary evidence for an association of EBV with pre-ulcerative oral aphthous lesions in RAU and BD patients.

Adolescent↗
PubMed1998

[Both myeloma cells and bone marrow stromal cells are involved in the overproduction of interleukin 6 in multiple myeloma].

OBJECTIVE: To investigate the mechanism of interleukin 6 (IL-6) overexpression in multiple myeloma(MM). METHODS: Human myeloma cells(KM3) and bone marrow stromal cells(BMSCs) were fixed by paraformaldehyde. KM3 cells and BMSCs (fixed and non-fixed) were co-cultured in 10%FCS-RPMI1640. IL-6 activity in the supernatant was determined by B9 cell proliferation test. RESULTS: Both non-fixed myeloma cells and BMSCs could automatically secret IL-6, while the fixed cells did not. Co-cultures of fixed one with non-fixed the other of either kind of the cells could significantly increase the IL-6 activity in the supernatants. The promoting effect on IL-6 production was greater in BMSCs from MM patients than that in BMSCs from normal controls. CONCLUSION: There exists dual mechanism of IL-6 overproduction in MM, i.e. both autocrine and paracrine of IL-6 are involved in the pathogenesis of MM.

Bone Marrow Cells↗
PubMed1998

[Reversal effect of Ys-96, a bisbenzylisoquinoline, on adriamycin or vincristine resistance in human cancer cells in vitro].

OBJECTIVE: Reversal effect of Ys-96, a bisbenzylisoquinoline, on the resistance of human cancer cells to adriamycin or vincristine was studied in vitro. METHOD: In an in vitro culture system of human cancer cells MCF-7 and its adriamycin-resistant line MCF-7/Ad or KB and its vincristine-resistant line KBv200, the sensitivity(IC50) of the resistant cell lines to adriamycin or vincristine was evaluated with a MTT assay. RESULT: IC50 value of adriamycin or vincristine in combination with Ys-96 at a concentration of 1.00 mumol/L against MCF-7/Ad or KBv200 was found to be close to that of adriamycin alone or vincristine alone against the sensitive cell line MCF-7 or KB. CONCLUSION: The drug resistance of MCF-7/Ad or KBv200 could be essentially reversed by Ys-96 at a concentration of 1.00 mumol/L.

Benzylisoquinolines↗
PubMed1997

[Synovial sarcoma in the head and neck with 3 case reports].

Synovial sarcoma in the head and neck with 3 cases are reported. Some clinical features and experiences of surgical excision are analysed according to our materials and review of the literature. We believe that the key to prevent synovial sarcoma from recurrence and matastasis is to avoid local excision, and pay more attention to this disease before operation. It is not sensitive to radiation therapy.

Adult↗
PubMed1997

[Disturbance of iron metabolism and sudden hearing loss: a prospective and retrospective survey].

Two hundred and eighteen patients with disorders of disturbance of iron metabolism, 215 with hematonosis and 4850 in a normal control group were studied in a prospective with sudden hearing loss and were meanwhile investigated in a retrospective review in order to evaluate the relationship between the disorders of disturbance of iron metabolism and sudden hearing loss. The findings revealed a significantly higher incidence of sudden hearing loss in the cases of disturbance of iron metabolism, than in the patients with hematonosis as well as in the normal control group. Iron deficiency and iron deficiency anemia were found in 60.84% of 429 patients with sudden hearing loss. We concluded that the risk of disturbance of iron metabolism in the cochlea will significantly increase when systemic disturbance of iron metabolism is present although the one does not necessarily indicate the other. It seems that acute disturbance of iron metabolism in cochlea causes sudden hearing loss directly or provides a pathologic basis for the disorder.

Adolescent↗
PubMed1996

In vitro assembly of the component chains of fibrinogen requires endoplasmic reticulum factors.

Human fibrinogen (340 kDa) is a dimer, with each identical half-molecule composed of three different polypeptides (Aalpha, 66 kDa; Bbeta, 55 kDa; and gamma, 48 kDa). To understand the mechanisms of chain assembly, a coupled in vitro transcription translation system capable of assembling fibrinogen chains was developed. Fibrinogen chain assembly was assayed in an expression system coupled to rabbit reticulocyte lysate in the presence or absence of dog pancreas microsomal membranes. Fibrinogen chain assembly required microsomal membranes and oxidized glutathione. Co-expression of two of the chains, Bbeta and gamma or Aalpha and gamma, yielded free chains and two-chain complexes. Unlike combinations of Aalpha with gamma and Bbeta with gamma, co-expression of Aalpha and Bbeta did not form a single two-chain complex but produced a mixture of two-chain complexes. Co-expression of all three chains yielded free chains, two-chain complexes, and higher molecular weight complexes that corresponded to a half-molecule and to fully formed fibrinogen. Upon treatment of this mixture with thrombin and factor XIIIa, a gamma.gamma dimer, similar to that obtained from cross-linked human fibrin, was produced, indicating that properly folded fibrinogen was formed in vitro. Molecular chaperones may participate in fibrinogen assembly, since antibodies to resident proteins of the endoplasmic reticulum (BiP, Hsp90, protein disulfide isomerase, and calnexin) co-precipitated the chaperones together with nascent fibrinogen chains and complexes.

Animals↗
PubMed1996

Dependence of epithelial intercellular junction biogenesis on thapsigargin-sensitive intracellular calcium stores.

Perturbation of potentially regulatable endoplasmic reticulum (ER) calcium stores with the Ca-ATPase inhibitor, thapsigargin (TG), perturbs the formation of desmosomes and tight junctions during polarized epithelial cell biogenesis, despite the development of cell contact. In a Madin-Darby canine kidney cell model for intercellular junction assembly, TG treatment inhibited the development of transepithelial electrical resistance (TER), a measure of tight junction assembly, in a dose-dependent manner. The TG-induced inhibition of tight junction assembly was paralleled by a defect in the sorting of the tight junction protein, ZO-1. An even more dramatic delay in sorting of the desmosomal protein, desmoplakin, was observed in the presence of TG. In addition, while both ZO-1 and desmoplakin-I in control cells were shown to become associated with the Triton X-100 insoluble cytoskeleton during intercellular junction assembly, prior treatment with 100 nM TG diminished this biochemical stabilization into the detergent-insoluble fraction, particularly in the case of ZO-1. Although spectrofluorimetric measurements in fura-2 loaded Madin-Darby canine kidney cells confirmed the occurrence of TG-mediated release of calcium from internal stores, total cytosolic calcium during junction assembly remained similar to untreated cells. Therefore, the presence of cytosolic calcium alone is not sufficient for normal intercellular junction biogenesis if intracellular stores are perturbed by TG. The results indicate the presence of calcium-sensitive intracellular mechanisms involved in the sorting and cytoskeletal stabilization of both tight junction and desmosomes and suggest a role for calcium-dependent signaling pathways at an early (possibly common) step in polarized epithelial biogenesis.

Animals↗
PubMed1996

Human cytomegalovirus as a potential etiologic agent in recurrent aphthous ulcers and Behçet's disease.

In a preliminary study on anti-human cytomegalovirus (HCMV) antibody (Ab) by ELISA, the serum anti-HCMV/IgG Ab concentrations in 22 patients with recurrent aphthous ulcers (RAU) in the remission stage were found to be significantly higher than in 22 control subjects (121 +/- 42 vs 100 +/- 27, P < 0.05) and in 39 patients with RAU in the active stage (121 +/- 42 vs 88 +/- 45, P < 0.01). Therefore, the potential of HCMV as an etiologic agent in RAU was proposed and studies using the polymerase chain reaction (PCR) and in situ hybridization (ISH) have been performed to investigate the possible presence of HCMV DNA in pre-ulcerative oral aphthous lesions in patients with RAU or Behçet's disease (BD) of the mucocutaneous type. For this purpose, formalin-fixed biopsy specimens were obtained from 13 pre-ulcerative oral aphthous lesions, 2 samples of normal oral mucosa and 1 ileal mucosal lesion from 9 RAU patients and 4 BD patients. Five specimens of normal oral mucosa from 5 normal control subjects and 12 specimens of oral erosive or ulcerative lesions from 12 patients with erosive lichen planus (ELP) were also included. By PCR, HCMV DNA was detected in 5 of the 13 (38.5%) pre-ulcerative oral aphthous lesions, 3 from RAU patients and 2 from BD patients. The ileal mucosa specimen was also HCMV DNA-positive, whereas HCMV DNA was not demonstrated in any of the 7 specimens of normal oral mucosa from RAU patients and normal control subjects; 12 specimens of oral lesions from ELP patients were similarly negative. ISH did not detect HCMV DNA in any of the biopsy specimens from RAU patients and control subjects. Our findings suggest that HCMV may be an etiologic agent in some cases of RAU and BD.

Adolescent↗