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Biomedical subjects

S Cheng

Publications and source records attributed to S Cheng.

At least 109 records · Page 6Linked to original sources
PubMed2000

[Effects of adhesive proteins on endothelialization of PC crosslinking yak pericardial materials--an experimental study].

To investigate the conditions of endothelialization of biomaterials, we examined in vitro the growth properties of endothelial cells on PC treated yak pericardial materials. After rinsed in normal saline (0.9%), the surface of PC crosslinking yak pericardial materials was precoated with three kinds of adhesive proteins--Laminin (La), Fibronectin(FN) and Collagen-I(CL-I). Ednothelial cells(EC) from the canine were seeded on the precoated materials, and on the uncoated materials as control. The result showed that in the La and FN groups the seeded EC survived and grew on the patches, while in the CL-I group and uncoated group the seeded EC on and around the patches did not continue to live. Conclusively, in this experiment, PC yak pericardial materials had cytotoxicity; the cytotoxicity of PC crosslinking yak pericardial materials could be decreased by La and FN precoating; La and FN promoted the adhesion and growth of EC on the PC yak pericardial materials patches; the materials met the needs of endothelialization in vitro, prominently in the La group; there was significant difference in endothelialization between La and FN groups (P < 0.05); CL-I had no part in promoting EC adhesion and growth.

Animals↗
PubMed2000

[Numerical alteration of chromosome 8 in pleural effusions].

OBJECTIVE: To study the numerical alteration of chromosome 8 and its application for detecting cancer cells in the pleural effusions. METHODS: In situ hybridization with chromosome 8 centromere probe was carried out in 52 patients with pleural effusions. RESULTS: In 31 lung cancer patients examined, hyperdiploid chromosome 8 was found in the effusions. The same hyperdiploid of the chromosome was also noted in 4 cases of effusion from adenocarcinoma of breast, mesothelioma and lymphoma. In 15 pleural effusions which were reportedly negative in previous cytological diagnosis, hyperdiploid chromosome 8 was found in 3 cases, and diploid chromosome 8 in another 12 cases by in situ hybridization. After reexemination of the samples from the 3 patients with hyperdiploid chromosome 8, adenocarcinoma cells were found in 2 cases, and the third one was a patient being treated with radiotherapy. Hyperdiploid chromosome 8 also existed in the pleural effusions from 2 cases suspicious of adenocarcinoma. CONCLUSION: Hyperdiploid chromosome 8 may be a useful marker to ascertain the malignant nature of pleural effusion.

Adult↗
PubMed2000

[Characteristics of producing-fumonisin and dimorphic fungus of fusarium moniliforme].

OBJECTIVE: To study the carcinogenesis of fusarium moniliforme and its fumonisins in animals. METHODS: The producing-fumonisin and dimorphic fungus pathogenicity of F. moniliforme from Zhejiang, China were identified and characterized. RESULTS: The F. moniliforme isolated from foodstuffs was shown to produces fumonisin B(1) > 400 microg/g in medium by IC-ELISA. Ten foodstuffs samples showed (2% - 100%) detection rate of F. moniliforme and contained fumonisin B(1) between (3.7 - 143.1) microg/g. The strains of F. moniliforme formed yeast-like colony in Sabouraud's agar plates contained 9% NaCl at 37degrees C incubator and budding multiplication mostly. In blood agar plates the strains of F. moniliforme showed grass green haemolytic reactions. CONCLUSION: It is important to carry out (or to perform) oulepidemiologicol survey of F. moniliforme as a primary pathogenic fungus, as well as the mycotoxins of F. moniliforme in vitro.

Carcinogens, Environmental↗
PubMed2000

[Study on spontaneous apoptosis of human non-small cell lung cancer tissues].

OBJECTIVE: To observe the spontaneous apoptosis in human non- small cell lung cancer (NSCLC) tissues, and the impact of PCNA and microvessel density on it. METHODS: TDT in situ labeling and immunohistochemistry were used to display apoptotic cells, PCNA and microvessels. RESULTS: The total forty-six cases of NSCLC were observed. Apoptosis index (AI) was 2.8% +/- 2.3% on average, and higher in squamous carcinomas (3.4% +/- 1.7%) than in adenocarcinomas (1.2% +/- 2.0%). AI in the poorly differentiated carcinomas (3.9% +/- 2.7%) was significantly higher than in the middle- and well-differentiated carcinomas (2.8% +/- 2.0%, 0.5% +/- 0.2% respectively). AI was higher in NSCLC with PCNA-positive cell rate >or= 25% (3.4% +/- 2.2%) than with PCAN-positive cell rate < 25% (1.9% +/- 2.2%). Microvessel density was higher in NSCLC with AI < 2% ( 74.4 +/- 29.6 counts/200 field) than with AI >or= 2% (42.0 +/- 12.8 counts/200 field). Apoptotic cells were frequently seen in the regions with less microvessels and distal to microvessels. CONCLUSIONS: Spontaneous apoptotic cells mainly occur in the tissues of squamous carcinomas and poorly-differentiated carcinomas and NSCLC with higher PCNA-positive cell rates. Hypoxia could induce apoptosis of lung cancer cells.

Adenocarcinoma↗
PubMed2000

[Effects of vitamin E and vitamin C on nonenzymatic glycation and peroxidation in experimental diabetic rats].

SD rats were peritoneally injected with streptozotocin (STZ) to establish diabetic animal model. The changes of nonenzymatic glycation and peroxidation in rats supplemented with vitamin C and/or vitamin E during five weeks were investigated. It was found that the glycated hemoglobin, glycated LDL, renal cortical AGEs and MDA in sera and renal cortex significantly decreased after supplementation of vitamins E and C jointly. It was also observed that the MDA in serum and the cortex of kidney but not glycated hemoglobin, glycated LDL and AGEs significantly decreased in the groups supplemented with vitamin C or vitamin E separately. The results suggested that joint supplementation of vitamin C and vitamin E could inhibit nonenzymatic glycation obviously and peroxidation in diabetic rats and protect the kidney from damage under hyperglycemia.

Animals↗
PubMed2000

[Detection of hyperdiploid in malignant cells in fine-needle aspirates from lung cancer by fluorescence in situ hybridization].

OBJECTIVE: To study the numerical abnormality of chromosomes in malignant cells in fine-needle aspirates from lung cancer by fluorescence in situ hybridization (FISH). METHODS: 30 fine-needle aspirates from lung cancer (4 from lung tissues, 26 from lymph nodes) were detected by FISH with the centromere DNA probes for chromosome 7, 11, 17 and X. RESULTS: In 27 positive fine-needle aspirates the rates of hyperdiploid in chromosome 7, X, 17, and 11 were 81.5% (22/27), 77.8% (21/27), 70.4% (19/27) and 63.0% (17/27), respectively. In 3 negative fine-needle aspirates, the number of chromosomes was normal. CONCLUSIONS: (1) Interphase cytogenetic cells analysis of fine-needle aspirates by FISH is feasible and simple; (2) Hyperdiploid in malignant cells in fine-needle aspirates from lung cancer can be used as a biomarker for benign and malignant cells.

Biopsy, Needle↗
PubMed1999

Laparoscopic living donor nephrectomy: advantages of the hand-assisted method.

INTRODUCTION: The laparoscopic technique for living donor nephrectomy is a technically difficult procedure that has not yet gained widespread acceptance in the transplant community. The procedure may be more acceptable if alterations to the technique made it easier to perform and decreased operative times. METHODS: In August 1998, we altered the laparoscopic procedure to include the use of a device allowing hand assistance. Subsequently, all living donor nephrectomies have been done using the hand-assisted method. In this article, the results of 10 cases performed using the original laparoscopic technique are compared with the results of 12 cases using the hand-assisted technique, and a brief description of modifications to the original technique is given. RESULTS: No patients where turned down as living donors, and no contraindications to the pure or hand-assisted laparoscopic techniques where found. The hand-assisted technique significantly reduced the operative time (2.02+/-0.44 vs. 3.12+/-0.36 hr, P<0.05) and the warm ischemic time (1.23+/-0.54 vs. 3.91+/-0.53 min, P<0.05). The length of stay and recovery time to normal activities were not different between the pure laparoscopic and hand-assisted groups. CONCLUSION: The advantages of the hand-assisted technique include the ability to use tactile sense to facilitate dissection, retraction, and exposure. In addition, the final stages of vascular stapling and kidney removal are more sure and rapid. The modifications of the laparoscopic technique presented here provide measurable and subjective improvements to laparoscopic living donor nephrectomy. The hand-assisted method of laparoscopic nephrectomy may make the operation available to more transplant centers.

Adolescent↗
PubMed1999

The prevalence of asthma symptoms, bronchial hyperresponsiveness and atopy in New Zealand adults.

AIMS: To examine the prevalence of asthma symptoms, bronchial hyperresponsiveness (BHR) and atopy in a random population sample of New Zealand adults. METHODS: A random sample of 2004 adults, aged 20-44 years, in Hawkes Bay, Wellington and Christchurch, were selected from respondents to a one-page respiratory screening questionnaire and invited to take part in further testing. Subjects attending the testing centres' laboratories underwent a detailed respiratory symptom questionnaire, Phazet testing to eleven common allergens, blood samples for total and specific IgE, and measurement of bronchial hyperresponsiveness. Subjects who did not wish to participate were encouraged to complete the questionnaire by telephone. RESULTS: A participation rate of 67% (1257 of 1877 eligibles) was achieved. We found a high prevalence for all measures of asthma in the previous 12 months: wheezing was reported by 28.5%, waking with shortness of breath by 7.7%, a physician diagnosis of asthma by 15.9% and asthma medications were used by 8.5%. Bronchial hyperresponsiveness was found in 24.9%, atopy in 34.8% and elevated serum IgE levels in 30.5%. Asthma symptoms (in the past 12 months) and atopy decreased with increasing age, whereas bronchial hyperresponsiveness increased with age. Females reported higher prevalences of waking with coughing (45.9%), nasal allergies (43.5%) and skin allergies (48.8%) compared to males (30.5%, 31.9% and 37.0%, respectively). There were no significant regional differences. CONCLUSIONS: Asthma symptoms, bronchial hyperresponsiveness and atopy are all common in adult New Zealanders. Their prevalence is associated with age, gender and current smoking but there are no significant regional differences between Hawkes Bay, Wellington and Christchurch.

Adult↗
PubMed1999

The EGF-CFC protein one-eyed pinhead is essential for nodal signaling.

The zebrafish EGF-CFC gene one-eyed pinhead (oep) is required zygotically for the formation of the ventral neuroectoderm, endoderm, and prechordal plate. Here we report that embryos lacking both maternal and zygotic Oep activity are defective in germ layer formation, organizer development, and the positioning of the anterior-posterior axis. An identical phenotype is displayed by double mutants for the nodal-related genes squint and cyclops. Mutations in oep eliminate the response to Squint and Cyclops overexpression but are suppressed by expression of Activin and activated forms of the type I receptor ActRIB and Smad2. Expression of the murine EGF-CFC gene cripto rescues oep mutants. These results suggest a conserved role for EGF-CFC proteins as essential extracellular cofactors for Nodal signaling during vertebrate development.

Activins↗
PubMed1999

Stimulation-induced changes in filopodial dynamics determine the action radius of growth cones in the snail Helisoma trivolvis.

Filopodia on neuronal growth cones constantly extend and retract, thereby functioning as both sensory probes and structural devices during neuronal pathfinding. To better understand filopodial dynamics and their regulation by encounters with molecules in the environment, we investigated filopodial dynamics of identified B5 neurons from the buccal ganglion of the snail Helisoma trivolvis before and after treatment with nitric oxide (NO). We have previously demonstrated that treatment with several NO-donors caused a transient, cGMP-mediated elevation in [Ca(2+)](i), which was causally related to an increase in filopodial length and a reduction in the number of filopodia on growth cones. We demonstrate here that these effects were the result of distinct changes in filopodial dynamics. The NO-donor SIN-1 induced a general increase in filopodial motility. Filopodial elongation after treatment with SIN-1 resulted from a significant increase in the rate at which filopodia extended, as well as a significant increase in the time filopodia spent elongating. The reduction in filopodial number was caused by a significant decrease in the frequency with which new filopodia were inserted into the growth cone. With the exception of the back where filopodia appeared less motile, filopodial dynamics appeared to be mostly independent of the location on the growth cone. These results suggest that NO can regulate filopodial dynamics on migrating growth cones and might function as a messenger to adjust the action radius of a growth cone during pathfinding.

Animals↗
PubMed1999

The economic impact of esophageal variceal hemorrhage: cost-effectiveness implications of endoscopic therapy.

Esophageal variceal hemorrhage (EVH) is a serious and expensive sequela of chronic liver disease, leading to increased utilization of resources. Today, endoscopic sclerotherapy (ES) and endoscopic ligation (EL) are the accepted, community standards of endoscopic treatment of patients with EVH. However, there are no published studies comparing the economic costs of treating EVH using these interventions. As part of a prospective, randomized trial comparing ES and EL for the treatment of EVH, we estimated the direct costs of health care utilization and cost-effectiveness for the prevention of variceal rebleeding and patient survival at 1-year follow-up. Treatment groups were similar in incidence of variceal rebleeding (41.9% vs. 42.9%), variceal obliteration (41.9% vs. 40.0%), hospital days, blood transfusions, shunt requirements, and survival (71.0% vs. 60.0%). There were significantly more treatment failures for active bleeding using EL (42% vs. 0%; P =.027) and esophageal stricture formation in the ES-treated patients (19.4% vs. 2.9%; P = 0.03). Median total direct cost outcomes were similar between groups (EL = $9,696 and ES = $13,197; P =.46). EL and ES had similar cost/variceal rebleeding prevented ($28,678 vs. $29,093) and cost/survival ($27,313 vs. $23,804). In the subgroup of active bleeders, ES had a substantially lower cost/survival ($28,523 vs. $51,696). We conclude that resource utilization was similar between treatment groups and that the choice of endoscopic therapy for EVH must still rely on clinical grounds. Further studies comparing costs and resource utilization in this patient population are needed.

Cost-Benefit Analysis↗
PubMed1999

Factors affecting broadband ultrasound attenuation results of the calcaneus using a gel-coupled quantitative ultrasound scanning system.

This study aimed to assess the factors that may influence the distribution and description of broadband ultrasound attenuation (BUA) and to identify specific criteria for diagnostic consideration when collecting BUA reference data. Two hundred Caucasian women (aged 20-79 years) without a history of atraumatic fractures or medicines known to affect bone metabolism were selected for this study. Medical and menstrual history, medication usage, family history of osteoporosis (FHO), physical activity, activities of daily living (ADL), dietary calcium intake, as well as smoking and alcohol consumption were obtained. Broadband ultrasound attenuation (BUA, dB/MHz) was determined in the right foot using a new gel-coupled ultrasound system. BUA was significantly associated with age (p<0.001), body weight (p<0.001), level of physical activity (p = 0.024) and dietary calcium intake (p = 0.023). Smoking, alcohol and coffee consumption and ADL were not associated with BUA (p>0.05). There were no differences in BUA (p>0.05) between those women who reported taking medications or had diseases (known to not affect bone metabolism), were using contraceptives, taking vitamin/mineral supplements and/or had traumatic fractures and their counterparts who did not report these characteristics. Premenopausal women with a FHO had significantly lower BUA values compared with those without a FHO (p = 0.013). When those participants with a FHO were removed from the sample, the peak BUA value was 1.1-4.4% higher and the variability (SD) was reduced by about 3.3-9.3% depending on which age range was used to define the peak BUA value. Consequently, an additional 4.5% of the population were classified as having a T-score <-2. Our results suggest that the impact on BUA of risk factors such as a FHO, body weight, physical activity and dietary calcium intake is similar to that on bone mineral density obtained by dual-energy X-ray absorptiometry (DXA), and thus provides further information on the comparability of quantitative ultrasound and DXA for assessment of risk of fracture. The criteria for calculating the T-score need further study to determine whether young adults with FHO should be included and what cutoff age range should be used in collecting peak values of quantitative ultrasound parameters.

Adult↗
PubMed1999

The role of collagen abnormalities in ultrasound and densitometry assessment: In vivo evidence.

There is little information concerning how the mutation of collagen affects bone mineralization and the assessment of bone properties. To estimate these influences, we performed ultrasonic assessments of the calcaneus and bone mineral density (BMD) measurements of the hip and lumbar spine. Females with diseases related to the mutation of collagen [Ehlers-Danlos syndrome (EDS) type III and systemic sclerosis (SSc)] participated in this study. We compared the broadband ultrasound attenuation (BUA and UBI-4), the average transit time through the heel (TTH), and a multiple factor index (UBI-4T) with control subjects matched on age, race, and menstrual status. Both groups of patients had BMD of the spine (L2-L4) within the normal range for their age and sex (for EDS: n = 23, 1.14 +/- 0. 14 g/cm2 and z-score = 0.37; for SSc: n = 15, 0.98 +/- 0.15 g/cm2 and z-score = 0.20). EDS and SSc subjects had lower BMD of the femoral neck (FN) compared with controls (for EDS: 0.91 +/- 0.13 g/cm2, z-score = -0.41, P = 0.025; for SSc 0.67 +/- 0.13 g/cm2, z-score = -0.92, P = 0.006). Subjects with EDS and SSc also had lower BUA values (P = 0.051-0.001) compared with controls. After adjusting for body weight, height, and the level of physical activity, the difference in FN BMD between EDS or SSc and controls became marginal (EDS: P = 0.072; SSc: P = 0.086). However, the significant difference for BUA between subjects and controls remained for EDS (P = 0.008), and disappeared for SSc (0.70) after adjusting for weight, height, level of physical activity, and BMD. These results suggest that the abnormalities of collagen may impact on bone mass measurements differently depending on skeletal site, modality of the assessment, and the source and nature of collagen defects. To determine whether collagen properties influence QUS, proper models in vivo and in vitro should be used.

Absorptiometry, Photon↗
PubMed1999

Titanium dioxide as photocatalyst on porous nickel: adsorption and the photocatalytic degradation of sulfosalicylic acid

The commonly used photocatalyst, TiO2 (anatase), has been immobilized on porous nickel using 3 wt.% polyvinyl alcohol (PVA) as the binder. The results show that sulfosalicylic acid (SSal) can be degraded on the developed catalytic system. The adsorption characteristics on TiO2-Ni system have been investigated. The observance of photocalytic degradation of SSal under pH values and initial concentrations can be explained by the adsorption behavior of SSal. The parameters of the Langmuir-Hinshelwood expression have been determined by different experimental ways and the results are satisfactory.

Journal Article↗
PubMed1999

Effects of altering dosing on cationic liposome-mediated gene transfer to the respiratory epithelium.

Liposome-mediated gene transfer is currently sub-optimal with respect to both the extent and duration of transgene expression. We investigated whether simple changes in DNA dosing could enhance either of these outcomes. Increasing DNA doses produced highest transgene expression at an intermediate dose with toxicity observed at higher doses, thereby likely limiting expression. Adminis- tering an equivalent DNA dose in aliquots over a 1-3 day period resulted in significantly lower gene expression and did not increase the duration of expression. Administration at different times of the day (and hence wake/sleep cycles of the animals) did not alter gene expression. We conclude that such simple changes in dosing regimes are unlikely to contribute to improvements in gene transfer efficiency.

Animals↗
PubMed1999

The relationship between anthropometric measurements at birth: asthma and atopy in childhood.

BACKGROUND: Recent studies have reported that a large head circumference at birth is associated with an increased risk of raised serum IgE in adult life, and asthma during childhood. OBJECTIVE: To examine the relationship between head circumference and other anthropometric measurements at birth and asthma and indices of atopy in childhood. METHODS: The presence of asthma and measures of atopic status (total serum IgE level and skin prick tests to common allergens) were assessed prospectively in offspring of families participating in a community-based genetic study in Southampton, UK. Measures of perinatal variables including birth weight, head circumference at birth, and gestational age were obtained from hospital records of 239 offspring aged 6-23 years. RESULTS: Children with a head circumference of 37 cm or more at birth had a relative risk of an elevated serum total IgE (> 150 IU) of 3.2 (95% CI 1.0-10.4). There were no consistent relationships between head circumference at birth and either skin prick positivity or the development of clinical asthma. There was no significant association between other perinatal markers and measures of atopic status or clinical asthma. CONCLUSION: The study has identified that a large head circumference at birth is associated with an increased risk of an elevated total serum IgE in childhood. The reasons for this association, and the lack of an association with asthma are unclear and will require further research.

Adolescent↗
PubMed1999

Synergism of energy starvation and dextran-conjugated doxorubicin in the killing of multidrug-resistant KB carcinoma cells.

Here we report that 2-deoxyglucose/Na azide treatment and free/conjugated doxorubicin are synergistic in cell killing. As demonstrated by fluorescence confocal microscopy, KB-V1 cells retained more conjugated doxorubicin than free doxorubicin. Verapamil or 2-deoxyglucose/Na azide enhanced only the retention of the free drug and the small (<70 kDa) conjugates, indicating that P-glycoprotein (P-gp) is not effective against large conjugates. Conjugated doxorubicin was excluded from nuclei. Initially both free and conjugated doxorubicin accumulated in cytoplasmic organelles. Upon 2-deoxyglucose/Na azide treatment, fluorescence labeling of organelles dissipated. Prolonged (24 h) incubation of conjugate-preloaded cells resulted in redistribution of some of the organelle-associated fluorescence to nuclei, suggesting decoupling. The appearance of free doxorubicin was confirmed by capillary electrophoresis. 2-Deoxyglucose/Na azide treatment also retarded decoupling. Our results suggest that energy starvation, in addition to increasing cellular retention of P-gp substrates, may affect cellular fate of conjugated drugs with a possible enhancing effect in cancer cell killing.

Antineoplastic Agents↗