Biomedical subjects

F Sun

Publications and source records attributed to F Sun.

At least 55 records · Page 3Linked to original sources

PubMed2000

Isolation of calcifiable vesicles from aortas of rabbits fed with high cholesterol diets.

Advanced arterial wall calcification in atherosclerosis imposes a serious rupturing effect on the aorta. However, the mechanism of dystrophic calcification linked to hyperlipidemia, that causes atherosclerosis remains unknown. Emerging morphological and biochemical evidence reveals that calcifiable vesicles may have a role in plaque calcification. To determine whether a high cholesterol diet can induce arterial calcification and produce or activate calcifiable vesicles in aortas, a rabbit model was used. After 2 months of daily high lipid feeding (supplemented with 2% cholesterol and 6% peanut oil), typical atherosclerotic lesions developed. However, the mineral, if present in aortas, was insufficient to be detected by Fourier transform-infrared spectroscopy (FT-IR) or alizarin red staining, indicative of a non-calcifying stage of atherosclerosis. Small segments of thoracic aortas were digested in a crude collagenase solution to release calcifiable vesicles. Vesicles were also isolated from normal aortas as control to consider the possibility that membrane vesicles may be produced by crude collagenase digestion, which could cause the degradation of some cells. Calcifiable vesicles were precipitated at 300,000 x g after subcellular particles were removed by centrifugation at 30,000 x g. Calcifiability of isolated vesicles was then tested using calcifying media containing physiological levels of Ca2+ and Pi and 1 mM ATP. Electron microscopic observations showed that the isolated vesicles were heterogeneous in size and shape and capable of depositing electron dense particles. Fourier transform infrared spectroscopic analysis of the deposited particles revealed the presence of an amorphous mineral phase. The spectroscopic mineral to matrix ratios, related to the amount of mineralization, indicated that vesicles from cholesterol-fed rabbits produced more minerals than control vesicles obtained from the normal aortas. Alizarin red staining for mineral further demonstrated substantially higher calcifiability of the experimental vesicles. A 3-5 h exposure of the vesicles to calcifying media caused significant deposition of 45Ca and 32Pi in a vesicle protein-concentration dependent manner. Similar to previously reported observations with human atherosclerotic aorta vesicles, rabbit vesicles were enriched in ATP-hydrolyzing enzymes including Mg2+- or Ca2+-ATPase and NTP pyrophosphohydrolase that are implicated in normal and pathological calcification. Altogether, these observations suggest that accumulation of the released calcifiable vesicles, as a result of high cholesterol diets, may have a role in dystrophic calcification in hyperlipidemia-related atherosclerosis.

Animals↗

PubMed2000

In vivo antioxidative activity of propolis evaluated by the interaction with vitamins C and E and the level of lipid hydroperoxides in rats.

In vivo antioxidative activity of propolis was evaluated on the basis of ameliorative effects on the oxidative stress induced by vitamin E deficiency in rats. The control group was fed vitamin E-deficient diet, and the propolis group was fed vitamin E-deficient diet supplemented with 1% of propolis for 4 and 8 weeks. Comparisons were made in tissue concentrations of vitamin C, vitamin E, and lipid hydroperoxides between these groups. No significant difference was observed in tissue vitamin E concentration between these groups after both 4 and 8 weeks. After 4 weeks, the plasma vitamin C concentration of the propolis group was significantly higher than that of the control group. After 8 weeks, the tissue concentrations of vitamin C in the kidney, stomach, small intestine, and large intestine of the propolis group were significantly higher than those of the control group. These results suggest that some components of propolis are absorbed to circulate in the blood and behave as a hydrophilic antioxidant that saves vitamin C. The concentration of lipid hydroperoxides in the large intestine of the propolis group was significantly lower than that of the control group after 8 weeks. These results suggest that propolis exerts its antioxidative effect where it is assumed to accumulate, such as on the kidney, where it is excreted, and on the gastrointestinal tract, where propolis influences these tissues even from the outside of the cell.

Animals↗

PubMed2000

Cytotoxicity, apoptosis, and viral replication in tumor cells treated with oncolytic ribonucleotide reductase-defective herpes simplex type 1 virus (hrR3) combined with ionizing radiation.

The viral ribonucleotide reductase (rR)-defective herpes simplex type-1 (HSV-1) virus (hrR3) has been shown previously to preferentially replicate in and kill tumor cells. This selectivity is associated with tumor cell up-regulation of mammalian rR. Ionizing radiation (IR) is currently used in the therapy of many malignancies, including glioblastoma, cervical carcinoma, and pancreatic carcinoma. IR has been shown to up-regulate mammalian rR in tumor cells and appears to increase the efficacy of at least one non-rR-deleted HSV-1 strain in an in vivo tumor model. Here, we test the hypothesis that a single therapeutic radiation fraction will increase the replication and toxicity of hrR3 for malignant cell lines in vitro. PANC-1 pancreatic carcinoma, U-87 glioblastoma, and CaSki cervical carcinoma cell lines were treated with varying doses of IR and subsequently infected with hrR3 or KOS (wild-type HSV-1 strain). Cell survival was then measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and trypan blue exclusion cytometry. At 72 hours posttreatment, irradiation with 2 Gy reduced survival from 100% to 76% in noninfected cells, from 61% to 48% in KOS-infected cells, and from 39% to 27% in hrR3-infected PANC-1 cells. As such, analysis of variance indicated that the toxicity of the two modalities was additive. Similar additivity was seen in U-87 MG and CaSki cells. Absolute survival of hrR3-infected or KOS-infected PANC-1 cells decreased as a function of time after treatment (24-72 hours) and multiplicity of infection (MOI) (0.05-5.0). However, the relative decrease in survival with the addition of IR to hrR3 or KOS in PANC-1 cells was not markedly affected by altering MOI (0.05-5.0), time (24-72 hours), radiation dose (2-20 Gy), or cell culture conditions (confluent/growth arrested). We used fluorescence-activated cell sorter analysis with the cationic lipophilic dye DiOC6 to quantify a reduction in mitochondrial membrane potential that'is associated with apoptosis. Fluorescence-activated cell sorter analysis indicated increased apoptosis in both hrR3- and IR-treated cells at 48-72 hours, with hrR3 alone producing the most induction. Viral yields from PANC-1 cells after irradiation and infection were examined. No significant differences were seen between irradiated and nonirradiated cells in viral replication, with hrR3 producing single-step titers of 3.1 +/- 0.9 x 10(5) and 4.0 +/- 1.2 x 10(5) plaque-forming units/mL in nonirradiated and irradiated cells. Thus, complementary toxicity was seen between IR and hrR3 or KOS, regardless of cell type, time, MOI, IR dose, or culture conditions, without evidence of augmented apoptosis or viral replication.

Apoptosis↗

PubMed2000

Globalization of U.S. health care services: assessment and implementation.

Globalization has become a commonly used term to describe the manner in which organizations in many industries have spread their operations and management to foreign countries. As the trend toward a global economy progresses, more and more industries, including health care, are looking to capitalize on its possible benefits. This article examines globalization in other industries and applies the tools used elsewhere to U.S. health care organizations.

Decision Making↗

PubMed2000

The effect of a special herbal tea on obesity and anovulation in androgen-sterilized rats.

A special herbal tea has been used to treat clomiphene-resistant anovulatory disease and obesity effectively, especially in polycystic ovary syndrome (PCOS) cases with hyperinsulinemia. The effect of the herbal tea on obesity and anovulation was investigated in androgen-sterilized rats (ASR). The ASR model was established by subcutaneous injection of 1.25 mg testosterone propionate to Sprague-Dawley female rats at the age of 9 days. Rats were sacrificed around 112 days of age. ASR manifested with PCO, anovulation, high food intake, elevated body weight, and obesity. Immunocytochemistry demonstrated that estrogen receptors (ER) were predominantly distributed in the cytoplasm of neuropeptide Y (NPY)-containing neurons in the preoptic area (POA), and the coexpression was also found in the nuclei and fibers of NPY-synthesizing neurons in the arcuate nucleus (ARC). Compared with that in normal control rats, NPY expression was increased, the numbers of ER in hypothalamic ARC-median eminence (ME) decreased, gonadotropin-releasing hormone (GnRH) levels in ME was decreased, serum estrogen (E2) and leptin were elevated, and follicular stimulating hormone (FSH) and luteinizing hormone (LH) levels were reduced significantly in ASR. Significantly negative correlations between NPY and ER or GnRH, and between leptin and FSH or LH were observed. A positive correlation existed between serum leptin and body weight. These metabolic-endocrine changes in ASR were normalized after feeding the herbal tea. Both obesity and hypogonadotropin were expressed in ASR. The abnormal ovarian hormone milieu (elevated E2 levels) may have enhanced NPY expression and resulted in less GnRH and gonadotropin secretion. The herbal tea reduced body weight and induced ovulation in ASR.

Animals↗

PubMed2000

Efficacy of troglitazone on body fat distribution in type 2 diabetes.

OBJECTIVE: The insulin-sensitizing action of troglitazone may be mediated through the activation of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and the promotion of preadipocyte differentiation in adipose tissue on which troglitazone has depot-specific effects. We investigated the relationship between efficacy of the drug and body fat distribution. Changes in body fat distribution were also investigated by long-term administration of the drug. RESEARCH DESIGN AND METHODS: Troglitazone was given at a dose of 400 mg/day to 20 patients with type 2 diabetes whose diet and sulfonylurea therapy produced unsatisfactory glycemic control (HbA(1c) >7.8%) and whose insulin secretory capacity was found to be preserved (postprandial C-peptide >3 ng/ml). HbA(1c) values, serum lipid levels, and body weight were measured monthly Body fat distribution was evaluated in subcutaneous (SC) and visceral fat using a computed tomography scan at umbilical levels before and after troglitazone therapy RESULTS: During the 1-year troglitazone treatment, HbA(1c) was significantly decreased (from 9.2 +/- 0.2 to 7.1 +/- 0.2%, P < 0.01), showing lowest values at 4-6 months, whereas body weight was significantly increased (BMI 24.6 +/- 0.6 to 25.7 +/- 0.6 kg/m2, P < 0.01). Reduction of HbA(1c) (deltaHbA(1c)) from the baseline value during treatment was significantly greater in obese patients (BMI >26 kg/m2) than in nonobese patients (-3.2 +/- 0.4 vs. -2.1 +/- 0.3%, P < 0.05) and was more significant in women than in men (-3.2 +/- 0.2 vs. - 1.4 +/- 0.2%, P < 0.01). The level of deltaHbA(1c) during treatment showed a significant negative correlation with SC fat area (r = -0.742, P < 0.01) but not with visceral fat area. Weight gain during troglitazone treatment resulted in increased accumulation of SC fat without a change in visceral fat area and, consequently. in a significant decrease in the visceral-to-SC fat ratio. CONCLUSIONS: Predominant accumulation of SC fat for the visceral fat tissue was an important predictor of the efficacy of troglitazone therapy in patients with type 2 diabetes. Greater efficacy of troglitazone was observed in women who were characterized by more accumulation of SC adipose tissue than men. Long-term administration of the drug resulted in weight gain with increased accumulation of SC adipose tissue, probably because of the activation of PPAR-gamma in the region.

Adipose Tissue↗

PubMed2000

Molecular cloning and expression of an inwardly rectifying K(+) channel from bovine corneal endothelial cells.

PURPOSE: To determine the presence of a putative inwardly rectifying K(+) channel in bovine corneal endothelial (BCE) cells and to characterize its molecular and electrophysiological properties. METHODS: An RT-PCR strategy was used to clone an IRK1 channel sequence from BCE mRNA. Northern blot analysis was used to confirm expression of this sequence in cultured BCE cells. Two-electrode voltage-clamp and whole-cell patch-clamp recordings were used to characterize the cloned channel expressed in Xenopus oocytes and the native channels in cultured BCE cells, respectively. RESULTS: A full-length (1284 bp) coding sequence that shares 99.7% nucleotide sequence and 100% amino acid sequence identity to bovine lens IRK1 (Kir2.1) was cloned. The authors designate this sequence BCE IRK1 or BCIRK1. Northern blot analysis indicated that BCIRK1 mRNA is expressed in cultured BCE cells with two major transcripts of 7.5 and 5.5 kb. BCIRK1 cDNA was subcloned into the vector, pcDNA3.1(-), and cRNA transcribed from the BCIRK1 cDNA clone was injected into Xenopus oocytes. Two-electrode voltage-clamp recordings from injected oocytes revealed inwardly rectifying K(+) currents that were blocked by external Ba(2+) and Cs(+) in a concentration- and voltage-dependent manner. Whole-cell patch-clamp recordings from dissociated cultured BCE cells revealed strongly inwardly rectifying K(+) currents with similar properties. CONCLUSIONS: Corneal endothelial cells express IRK1 (Kir2.1) inwardly rectifying K(+) channels. Consistent with the properties of IRK1 channels, BCIRK1 is likely involved in regulating membrane potential and possibly other cellular functions in corneal endothelial cells.

Amino Acid Sequence↗

PubMed2000

[A study of sleep apnea monitoring method and instrument].

In this paper the fundamental principle and great significance of sleep apnea monitoring are introduced, and the status quo of this field at home and abroad is described. Several kinds of methods for sleep apnea monitorin are analyzed, and on this basis the authors have developed a cheap and portable sleep apnea monitoring instrument. Experiment results demonstrate that the instrument is of convenience, high accuracy and good performance.

Adult↗

PubMed2000

[Biological characteristics and occurrence regularity of Phassus excrescens Bulter].

The biological characterisitics and occurrence regularity of Phassus excrescens were studied from 1997 to 2000 in the eastern part of Heilongjiang Province and Jilin Province. In this area, most of its individuals took two years to finish one generation, and over-wintered two times with eggs and larvae, respectively. At the end of June or the first ten days of July, larvae transferred to damage Fraxinus mandshurica. Feeding with artificial diet indoor, the larvae finished 6 instars before pupation. In artificial Manchurican ash forest, the larva mainly damaged the truck basal(below 20 cm) or truck of 2 to 20 years old Fraxinus mandshurica. The occurrence amount of this species was closely related to the forest age and the stand structure. Usually, pure artificial Fraxinus mandshurica stands and Fraxinus mandshurica-Pinus koraiensis mixed stands were damaged seriously, while Fraxinus mandshurica-Larix mixed forests were damaged lightly.

Animals↗

PubMed2000

[The application of auro-galvano-form ceramic crowns in clinic].

OBJECTIVE: To evaluate the effects of auro-galvano-form ceramic crown in clinic. METHODS: The Ni-Cr alloy high-gold alloy and auro-galvano-form ceramic crowns were made respectively. Every kind was 200 pieces. 600 piece crowns were in total for 298 patients. The color of ceramic crowns was checked with Shade Eye. The color, fitness and fracture of ceramic crowns were checked in clinic. RESULTS: The results showed the aurogalvano-form ceramic crowns was similar to high-gold alloy ceramic crowns in color and fitness in clinic (P > 0.05). The effects of them were better than Ni-Cr alloy ceramic crowns in color and fitness significantly (P < 0.05). The fracture of 600 ceramic crowns was not found out in two years. CONCLUSIONS: The effects of auro-galvano-form ceramic crowns were perfect in color, fitness and fracture. It can be used in clinic.

Adolescent↗

PubMed2000

[Effect of acupuncture on level of monoamines and activity of adenosine triphosphatase in lateral hypothalamic area of obese rats].

OBJECTIVE: To study the mechanism of acupuncture in treating simple obesity. METHODS: Central nerve push-pull perfusion and biochemical technique were used to observe the effect of acupuncture on obese rats, and the obese parameters and the change of monoamine transmitters and activity of ATPase in the lateral hypothalamic area (LHA) of the obese rats were investigated. RESULTS: The levels of noradrenaline (NA) in LHA of obese rats were higher than those in the normal group, but the level of serotonin (5-HT) and the activity of ATPase in LHA of obese rats were lower than those of the normal rats. After acupuncture treatment, the weight of the obese rats reduced, while the level of NA in LHA reduced and the 5-HT and activity of ATPase increased (P < 0.05, P < 0.01). CONCLUSION: The effective regulation on LHA of obese rats is possibly one of the key factors in the anti-obesity of acupuncture.

Acupuncture↗

PubMed2000

[Effect of tiangui recipe on expressions of hypothalamic leptin receptor and messenger ribonucleic acid of neuropeptide Y in androgen-sterilized rats].

OBJECTIVE: To explore the effect of Tiangui Recipe (TGR) on obesity and anovulation in androgen-sterilized rats (ASR) from the gene transcription level. METHODS: In situs hybridization and autoradiography were adopted, using alpha-32 P-radiolabelled leptin receptor (OB-R) and neuropeptide Y (NPY) oligonucleotides probes and integrating with image pattern analysis, to observe the effect of TGR on changes of OB-R, NPY mRNA expression in the hypothalamic arcuate nucleus (ARC). RESULTS: Compared to the normal rats, the levels of hypothalamic OB-R mRNA expression decreased, NPY mRNA expression elevated significantly in ASR (P < 0.01). ASR characterized by obesity and anovulation. There was no significant difference in hypothalamic OB-R, NPY mRNA expressions between normal rats and ASR with TGR administration. CONCLUSION: The increased hypothalamic NPY and decreased OB-R mRNA expression may be important contributing factors to the development of obesity and anovulation in ASR. TGR may play a role in reducing weight and inducing ovulation by regulating NPY/OB-R mRNA expression.

Animals↗

PubMed2000

[Surgical approaches of pheochromocytoma].

OBJECTIVE: To evaluate the effects of surgery of Pheo. METHODS: Pheochromocytoma was removed in 89 patients. RESULTS: In 39 patients, pheochromocytoma was removed by intercostal incision at the 11th rib and 15 at the 10th rib, 14 by transrectal incision, 9 by abdominothoracic incision, 5 by abdominal subcostal oblique incision, 3 by inferior abdominal incision, 3 by posterolateral incision. One patient received laparoscopic surgery. CONCLUSIONS: Pheochromocytoma definitely localized was removed by intercostal incision at the 10th or 11th rib. The suitable pathway for removal giant pheochromocytoma or pheochromocytoma related big vessels is transrectal incision or abdominothoracic incision. The incision of multiple pheochromocytoma or extra-adrenal pheochromocytoma may be in the middle of the abdomen.

Abdomen↗

PubMed2000

[Diagnosis and treatment of pheochromocytoma].

OBJECTIVE: To improve the diagnosis and treatment of pheochromocytoma. METHODS: From 1958 to 1998, 286 cases of pheochromocytoma, confirmed by open surgery and pathology, were retrospectively analyzed. RESULTS: The tumors in the adrenal gland were seen in 220 cases, and in the external adrenal gland in 66. Of 29 cases of malignant pheochromocytomas, 7 were noted in the adrenal and 22 in the external adrenal gland. 19 cases showed stationary pheochromocytomas without clinical features. Total resections were performed in 281 cases. CONCLUSION: The operative mortality could be reduced by the prevention of potential myocardiopathy. The diagnosis of malignant pheochromocytoma should depend upon the long-term follow up.

Adolescent↗

PubMed2000

[Study on the protective effect of grape procyanidins on DNA damage induced by irradiation].

OBJECTIVE: To study the protective effect of grape procyanidins (GPC) on the irradiated DNA damage. METHOD: In vivo study: After orally administration of GPC, mice in different groups were exposed to whole-body (60)Co gamma-rays at a dose of 2.0 Gy and the fluorospectrometry method was used to rapidly detect the DNA strand breaks of mouse spleen cells. In vitro study: Human venous blood with different concentrations of GPC was exposed to (60)Co gamma-rays at a dose of 1.0 Gy, then WBC DNA content was measured after 1, 30 and 60 min exposure, respectively. RESULTS: In the three treated groups (500, 250 and 50 mg/kg of procyanidins), DNA content of mouse spleen cells was 18.76%, 15.74% and 5.06% more than that of the positive controls respectively. DNA content of human WBC was higher than the positive controls by 17.6%, 11.1% and 3.9% increase respectively one minute after irradiation and 21.3%, 13.8% and 5.3% increase respectively 60 min after irradiation. These differences were all statistically significant. CONCLUSION: GPC has a protective effect on DNA damage caused by irradiation, and is helpful to DNA repair.

Animals↗

PubMed1999

Increase of caspase-3 activity in rat liver and plasma by thioacetamide.

Twelve and twenty-four hours after intraperitoneal administration of thioacetamide (200 mg/kg body weight) to rats, caspase-3 activity in the liver and plasma of the treated rats increased significantly compared with that of the control group. These results demonstrated that thioacetamide caused apoptosis, which involved activation of caspase-3, although there may be a number of pathways to apoptosis in the liver that may or may not involve the activation of this protein. The results also indicated that the activated caspase-3 was released in plasma along with glutamate-oxaloacetate transaminase (GOT) by successive necrosis. This is the first study that shows an increase of caspase-3 activity in plasma.

Animals↗

PubMed1999

Transmission disequilibrium test (TDT) when only one parent is available: the 1-TDT.

The transmission disequilibrium test (TDT) is a useful method to locate mutations linked to disease genes associated with complex diseases. TDT requires genotypes of affected individuals and their parents. Recently, Ewens and Spielman (Am J Hum Genet 1998;62:450-8) extended the TDT for use in sibships with at least one affected and one unaffected individual and devised a new test called the sib transmission/disequilibrium test (S-TDT). The S-TDT can be applied to diseases with late age at onset such as non-insulin-dependent diabetes mellitus, psychiatric disorders, and diseases related to aging. For some disorders, it might be relatively easy to obtain the genotype of one parent either because the other parent is not available for study or he/she is not cooperative. Curtis and Sham (Ann Hum Genet 1995;59:323-36) showed that bias in transmitting certain alleles is introduced if only heterozygous parents and homozygous offspring are used in the TDT. In this paper, the authors propose a new test, the 1-TDT, to detect linkage between a candidate locus and a disease locus using genotypes of affected individuals and only one available parent for each affected individual. The test is not biased under the null hypothesis of no linkage or association. The authors validate their test using both simulated and real data sets. Finally, they show how to combine data from different types of families.

Age of Onset↗

PubMed1999

Comparison of arithmetic and geometric means as measures of a central tendency in cattle nematode populations.

Efficacy calculations in anthelmintic studies require estimates of the central tendency for the nematode populations. Confusion exists among practitioners regarding which measures of central tendency are most appropriate; although the arithmetic mean is frequently used, there are theoretical reasons for preferring the geometric mean. To investigate this controversy, arithmetic and geometric means were compared for their suitability for use in measuring efficacy. Arithmetic and geometric means were compared as measures of central tendency for skewed distributions. The following criteria were developed to facilitate the comparison: (1) probability around the parameter, (2) influence of extreme values, and (3) proximity to the median. Under log-normality, theoretical results demonstrated the superiority of the geometric mean. Modified-bootstrap simulations using empirical data from cattle were used to confirm theoretical expectations. Simulations on log-normal data supported the geometric mean as the better indicator of the central tendency. Additionally, for data not confirmed as log-normal, the superiority of geometric means was demonstrated. In a comparison of precision, it was shown that mean squared error was always smaller for sample geometric means than for arithmetic means when n> or =2. Simulation results added support to that conclusion.

Animals↗