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H W Yeung

Publications and source records attributed to H W Yeung.

At least 19 recordsLinked to original sources
PubMed2006

The angiosuppressive effects of 20(R)- ginsenoside Rg3.

Aberrant angiogenesis is an essential step for the progression of solid tumors. Thus anti-angiogenic therapy is one of the most promising approaches to control tumor growth. In this study, we examined the ability of 20(R)-ginsenoside Rg3 (Rg3), one of the active compounds present in ginseng root, to interfere with the various steps of angiogenesis. Rg3 was found to inhibit the proliferation of human umbilical vein endothelial cells (HUVEC) with an IC50 of 10 nM in Trypan blue exclusion assay. Rg3 (1-10(3) nM) also dose dependently suppressed the capillary tube formation of HUVEC on the Matrigel in the presence or absence of 20 ng/ml vascular endothelial growth factor (VEGF). The VEGF-induced chemoinvasion of HUVEC and ex vivo microvascular sprouting in rat aortic ring assay were both significantly attenuated by Rg3. In addition, Rg3 (150 and 600 nM) remarkably abolished the basic fibroblast growth factor (bFGF)-induced angiogenesis in an in vivo Matrigel plug assay. The Matrix metalloproteinases (MMPs), such as MMP-2 and MMP-9, which play an important role in the degradation of basement membrane in angiogenesis and tumor metastasis present in the culture supernatant of Rg3-treated aortic ring culture were found to decrease in their gelatinolytic activities. Taken together, these data underpin the anti-tumor property of Rg3 through its angiosuppressive activity.

Angiogenesis Inhibitors↗
PubMed2005

Elucidation of the mechanisms underlying the angiogenic effects of ginsenoside Rg(1) in vivo and in vitro.

The major active constituents of ginseng are ginsenosides, and Rg(1) is a predominant compound of the total extract. Recent studies have demonstrated that Rg(1) can promote angiogenesis in vivo and in vitro. In this study, we used a DNA microarray technology to elucidate the mechanisms of action of Rg(1). We report that Rg(1) induces the proliferation of HUVECs, monitored using [(3)H]-thymidine incorporation and Trypan blue exclusion assays. Furthermore, Rg(1) (150-600 nM) also showed an enhanced tube forming inducing effect on the HUVEC. Rg(1) was also demonstrated to promote angiogenesis in an in vivo Matrigel plug assay, and increase endothelial sprouting in the ex vivo rat aorta ring assay. Differential gene expression profile of HUVEC following treatment with Rg(1) revealed the expression of genes related to cell adhesion, migration and cytoskeleton, including RhoA, RhoB, IQGAP1, CALM2, Vav2 and LAMA4. Our results suggest that Rg(1) can promote angiogenesis in multiple models, and this effect is partly due to the modulation of genes that are involved in the cytoskeletal dynamics, cell-cell adhesion and migration.

Cell Adhesion↗
PubMed2005

FDG-PET scanning for detection and staging of extranodal marginal zone lymphomas of the MALT type: a report of 42 cases.

BACKGROUND: Although reports have suggested that FDG-PET scans were not useful for staging of extranodal marginal zone lymphomas (MZL), experience at our center suggests otherwise. Thus we reviewed the findings of FDG-PET scans in patients with extranodal MZL seen at our center. PATIENTS AND METHODS: A database of 175 patients with histologically-confirmed diagnoses of extranodal MZL was reviewed. Forty-two patients who had had FDG-PET scans for initial staging were identified. All information was obtained by retrospective review of medical records and PET scans. RESULTS: Thirty-four (81%) patients had focal tracer uptake within verified tumor sites, six (14%) patients did not, and two (5%) patients had indeterminate uptake. Seven of the 34 (21%) patients with uptake within verified tumor sites had uptake in regional lymph nodes and four patients were upstaged due to FDG-PET findings. Eight patients also obtained post-treatment FDG-PET scans. In five of those eight, the repeated FDG-PET scan indicated a complete response, and in three there was an indeterminate or mixed response. CONCLUSION: FDG-PET scans carried out for initial staging of extranodal MZL detected disease in a high proportion of patients. This study suggests that imaging with FDG-PET scans is useful for both initial staging and follow-up of patients with extranodal MZL.

Adult↗
PubMed2001

Standardized uptake value in pediatric patients: an investigation to determine the optimum measurement parameter.

Although the standardized uptake value (SUV) is currently used in fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging, concerns have been raised over its accuracy and clinical relevance. Dependence of the SUV on body weight has been observed in adults and this should be of concern in the pediatric population, since there are significant body changes during childhood. The aim of the present study was to compare SUV measurements based on body weight, body surface area and lean body mass in the pediatric population and to determine a more reliable parameter across all ages. Sixty-eight pediatric FDG-PET studies were evaluated. Age ranged from 2 to 17 years and weight from 11 to 77 kg. Regions of interest were drawn at the liver for physiologic comparison and at FDG-avid malignant lesions. SUV based on body weight (SUV(bw)) varied across different weights, a phenomenon less evident when body surface area (SUV(bsa)) normalization is applied. Lean body mass-based SUV (SUV(lbm)) also showed a positive correlation with weight, which again was less evident when normalized to bsa (SUV(bsa-lbm)). The measured liver SUV(bw) was 1.1+/-0.3, a much lower value than in our adult population (1.9+/-0.3). The liver SUV(bsa) was 7.3+/-1.3. The tumor sites had an SUV(bw) of 4.0+/-2.7 and an SUV(bsa) of 25.9+/-15.4 (65% of the patients had neuroblastoma). The bsa-based SUVs were more constant across the pediatric ages and were less dependent on body weight than the SUV(bw). These results indicate that SUV calculated on the basis of body surface area is a more uniform parameter than SUV based on body weight in pediatric patients and is probably the most appropriate approach for the follow-up of these patients.

Adolescent↗
PubMed2001

Extending positron emission tomography scan utility to high-risk neuroblastoma: fluorine-18 fluorodeoxyglucose positron emission tomography as sole imaging modality in follow-up of patients.

PURPOSE: Although positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose ((18)F-FDG) has a major impact on the treatment of adult cancer, the reported experience with extracranial tumors of childhood is limited. We describe a role for PET in patients with neuroblastoma (NB). PATIENTS AND METHODS: In 51 patients with high-risk NB, 92 PET scans were part of a staging evaluation that included iodine-123 or iodine-131 metaiodobenzylguanidine (MIBG) scan, bone scan, computed tomography (and/or magnetic resonance imaging), urine catecholamine measurements, and bone marrow (BM) examinations. The minimum number of tests sufficient to detect NB was determined. RESULTS: Of 40 patients who were not in complete remission, only 1 (2.5%) had NB that would have been missed had a staging evaluation been limited to PET and BM studies, and 13 (32.5%) had NB detected by PET but not by BM and urine tests. PET was equal or superior to MIBG scans for identifying NB in soft tissue and extracranial skeletal structures, for revealing small lesions, and for delineating the extent and localizing sites of disease. In 36 evaluations of 22 patients with NB in soft tissue, PET failed to identify only two long-standing MIBG-negative abdominal masses. PET and MIBG scans showed more skeletal lesions than bone scans, but the normally high physiologic brain uptake of FDG blocked PET visualization of cranial vault lesions. Similar to MIBG, FDG skeletal uptake was diffusely increased with extensive or progressing BM disease but faint or absent with minimal or nonprogressing BM disease. CONCLUSION: In the absence or after resolution of cranial vault lesions, and once the primary tumor is resected, PET and BM tests suffice for monitoring NB patients at high risk for progressive disease in soft tissue and bone/BM.

3-Iodobenzylguanidine↗
PubMed2001

Fludeoxyglucose positron emission tomography in the diagnosis of giant cell arteritis.

We describe a case in which fludeoxyglucose F 18 positron emission tomography (PET) led directly to the diagnosis of giant cell arteritis in an elderly woman with a fever of unknown origin. The patient presented with a 3-month history of fatigue, fever, headache, visual disturbance, jaw claudication, and anemia. A computed tomographic scan showed an anterior mediastinal mass that was suspected of being malignant. A fludeoxyglucose F 18 PET scan performed for preoperative evaluation identified striking uptake of fludeoxyglucose F 18 in the walls of the entire aorta, left main coronary artery, and subclavian, carotid, and common iliac arteries bilaterally, suggestive of an arteritis, a diagnosis subsequently confirmed by the findings of an arterial biopsy. Her erythrocyte sedimentation rate was 129 mm/h. There was normalizaton of the PET scan 2 weeks following treatment with prednisolone. This case suggests that fludeoxyglucose F 18 PET contributes to the noninvasive diagnosis of giant cell arteritis, as well as to the evaluation of the extent of disease, response to therapy, and disease recurrence.

Aged↗
PubMed2001

FDG-PET standardized uptake values in normal anatomical structures using iterative reconstruction segmented attenuation correction and filtered back-projection.

Filtered back-projection (FBP) is the most commonly used reconstruction method for PET images, which are usually noisy. The iterative reconstruction segmented attenuation correction (IRSAC) algorithm improves image quality without reducing image resolution. The standardized uptake value (SUV) is the most clinically utilized quantitative parameter of [fluorine-18]fluoro-2-deoxy-D-glucose (FDG) accumulation. The objective of this study was to obtain a table of SUVs for several normal anatomical structures from both routinely used FBP and IRSAC reconstructed images and to compare the data obtained with both methods. Twenty whole-body PET scans performed in consecutive patients with proven or suspected non-small cell lung cancer were retrospectively analyzed. Images were processed using both IRSAC and FBP algorithms. Nonquantitative or gaussian filters were used to smooth the transmission scan when using FBP or IRSAC algorithms, respectively. A phantom study was performed to evaluate the effect of different filters on SUV. Maximum and average SUVs (SUVmax and SUVavg) were calculated in 28 normal anatomical structures and in one pathological site. The phantom study showed that the use of a nonquantitative smoothing filter in the transmission scan results in a less accurate quantification and in a 20% underestimation of the actual measurement. Most anatomical structures were identified in all patients using the IRSAC images. On average, SUVavg and SUVmax measured on IRSAC images using a gaussian filter in the transmission scan were respectively 20% and 8% higher than the SUVs calculated from conventional FBP images. Scatterplots of the data values showed an overall strong relationship between IRSAC and FBP SUVs. Individual scatterplots of each site demonstrated a weaker relationship for lower SUVs and for SUVmax than for higher SUVs and SUVavg. A set of reference values was obtained for SUVmax and SUVavg of normal anatomical structures, calculated with both IRSAC and FBP image reconstruction algorithms. The use of IRSAC and a gaussian filter for the transmission scan seems to give more accurate SUVs than are obtained from conventional FBP images using a nonquantitative filter for the transmission scan.

Aged↗
PubMed2001

Aquiledine and isoaquiledine, novel flavonoid alkaloids from Aquilegia ecalcarata.

Two new flavonoid alkaloids, aquiledine (1) and isoaquiledine (2), were isolated from the whole herb of Aquilegia ecalcarata, and their structures were determined by detailed spectral analysis. Three known flavonoids were also isolated from this extract-apigenin, apigenin-7,4'-dimethyl ether, and luteolin-and have not been reported previously from A. ecalcarata.

Alkaloids↗
PubMed2001

Differentiation of Lycium barbarum from its related Lycium species using random amplified polymorphic DNA.

The RAPD (random amplified polymorphic DNA) technique was applied for the first time to distinguish Lycium barbarum from other closely related species of the same genus. In this study, eight samples were collected, including five species, two varieties and one cultivated variety. A total of fifty arbitrary primers were used in the RAPD analysis. Distinctive DNA fingerprints corresponding to different Lycium species were successfully obtained from ten primers. Similarity index (S.I.) analysis revealed that the values are higher between intraspecies than interspecies. These results confirmed that the RAPD technique can be employed for distinguishing closely related species of Lycium.

Base Sequence↗
PubMed2001

Incidental focal thyroid uptake on FDG positron emission tomographic scans may represent a second primary tumor.

PURPOSE: This article discusses the value of incidental thyroid uptake of fluorodeoxyglucose (FDG) on whole-body positron emission tomography (PET) scans performed in patients with cancer. This issue has been reported diversely in the literature. MATERIALS AND METHODS: Whole-body PET scans of four patients with cancer (two of them women; age, 49 to 78 years) in whom focal thyroid uptake was visualized and subsequently correlated with thyroid carcinoma based on cytologic or histopathologic data were reviewed. The clinical outcomes of these patients were analyzed retrospectively. Maximum and average standardized uptake values (SUVs) of thyroid accumulation were recalculated in all patients. RESULTS: Two of the four patients referred for FDG PET scans had lung adenocarcinomas, one had prostate carcinoma, and one had an unknown primary tumor. Focal thyroid uptake was visualized, with maximum and average SUVs ranging from 3.7 and 2.3 to 53 and 34, respectively. These findings were correlated with cytologic (two patients) or histopathologic data (two patients) that indicated thyroid carcinoma. In two patients, their treatment was changed and total thyroidectomy was performed; in one of them the SUVs of the focal thyroid accumulation (maximum and average values of 7.9 and 4.8, respectively) were less than the cutoff values for thyroid cancer noted in the literature. The clinical condition of the other two patients did not permit additional investigation or treatment for thyroid carcinoma. CONCLUSION: Increased focal thyroid uptake on whole-body FDG PET scans should not be overlooked, even when it is not marked, and should prompt further investigation to rule out cancer.

Adenocarcinoma↗
PubMed2001

Lymphoscintigraphy and sentinel node localization in breast cancer patients: a comparison between 1-day and 2-day protocols.

UNLABELLED: The purpose of this study was to compare the results of isotope injection the morning of surgery (1-d protocol) with isotope injection the day before surgery (2-d protocol) in patients having sentinel lymph node (SLN) biopsy for breast cancer. METHODS: The 1-d (protocol 1) and 2-d (protocol 2) protocols included 514 and 152 patients, respectively, treated contemporaneously by surgeons experienced with the SLN biopsy technique. All had preoperative lymphoscintigraphy (LSG) and SLN biopsy using both blue dye and (99m)Tc-sulfur colloid. All patients had a single-site intradermal injection of unfiltered (99m)Tc-sulfur colloid in 0.05 mL normal saline: 3.7 MBq (0.1 mCi) on the morning of surgery for protocol 1 and 18.5 MBq (0.5 mCi) on the afternoon before surgery for protocol 2. RESULTS: The patients in protocols 1 and 2 were comparable in terms of age, tumor size, tumor location, histologic type, node positivity, and frequency of a previous surgical biopsy. Comparing protocols 1 and 2, early (30 min) LSG images found the SLN equally often (69% vs. 68%). Isotope identified the SLN equally often at surgery (93% vs. 97%) as did isotope plus dye (98% vs. 99%). A comparable number of SLNs was found (2.5 vs. 2.8 per axilla), and the concordance between isotope and dye in the SLN was also comparable (97% vs. 95%). Late LSG images (at 2 h, possible only for protocol 2) identified the SLN in significantly more patients compared with early images (86% vs. 68%). CONCLUSION: With unfiltered (99m)Tc-sulfur colloid injected intradermally, the results of SLN biopsy under the 1-d and 2-d protocols are virtually identical. A 2-d protocol allows increased efficiency in scheduling, both for nuclear medicine physicians and for the operating room, with no compromise in the effectiveness of SLN mapping.

Adult↗
PubMed2001

[A rapid method for the identification of four different features of gouqizi by FTIR spectrometry].

In this article, a method of using Fourier-transform infrared (FTIR) spectrometry to identify four Lyeium barbarum L. (Gouqizi) in turn of colour, shape, taste and water content. The four features (include color is red or black, shape is round or long, quality is dry or wet, taste is sweet or bitter) are related with the FTIR absorption peaks, this is based on the chemical components and their relative contents are different in various Gouqizi. These differences can be reflected in the FTIR spectra. So a new idea is brought up in the research area of identification of traditional Chinese medicine. Alao, FTIR is proved to be a rapid, simple, reliable and non-destructive qualification method.

Drugs, Chinese Herbal↗
PubMed2000

Micelle-mediated extraction and preconcentration of ginsenosides from Chinese herbal medicine.

The feasibility of employing micelle-mediated extraction as an alternative and effective method for the solubilization, purification and/or preconcentration of active ingredients from herbal products is demonstrated for the first time using the root of American ginseng as a model. When compared to methanol and water, an aqueous surfactant solution containing 10% Triton X-100 yielded faster kinetics and higher recovery for the extraction of various ginsenosides. An experimental design approach (uniform design) was demonstrated as a novel and useful method for the optimization of experimental factors involved in the micelle-mediated extraction process. For the preconcentration of ginsenosides prior to chromatographic determination, a salting-out agent (sodium sulfate) was employed to make the efficient cloud point extraction of both hydrophobic and hydrophilic ginsenosides into the surfactant-rich phase possible, as well as to increase the preconcentration factor by reducing the volume of the surfactant-rich phase.

Chromatography, High Pressure Liquid↗
PubMed2000

Ga-67 uptake in cutaneous lesions of graft-versus-host disease.

Acute graft-versus-host disease (GVHD) usually involves the skin, gastrointestinal tract, and liver. A 47-year-old woman with fever of unknown origin was referred for a Ga-67 scan. The study showed diffuse uptake of Ga-67 throughout the skin. Subsequently, a skin biopsy confirmed the diagnosis of acute GVHD. The incidence, diagnosis, and pathophysiology of the dermatitis in acute GVHD are discussed.

Female↗
PubMed2000

Radioiodine uptake in thyroid remnants during therapy after tracer dosimetry.

UNLABELLED: Our objective was to evaluate the effect of a diagnostic tracer dose of 131I on the uptake of the therapeutic dose of 1311 in the ablation of a thyroid remnant or residual tumor in patients with differentiated thyroid cancer. METHODS: Twelve consecutive patients referred for a dosimetric study and subsequent radioiodine treatment of focal neck uptake of 131I were studied. The 24-h (in 1 case, 48-h) neck activity was calculated by the region-of-interest method, after both dosimetric and therapeutic administrations. The focal activity in the neck was corrected for decay and compared with the total activity administered to obtain the percentage uptake at 24 h. This procedure was performed for both the scanning dose (range, 19.8-196.1 MBq; mean, 85.1 MBq; median, 40 MBq) and the therapeutic dose (range, 1.073-5.713 GBq; mean, 2.991 GBq). The uptake of the therapeutic dose was then expressed as a percentage of the uptake of the diagnostic dose (%T/D). Counting rate linearity was established up to 350 MBq in the field of view of the gamma camera used in the study. RESULTS: Thirteen of a total of 16 lesions exhibited reduced uptake from the therapeutic dose, 2 remained the same, and in 1 the uptake actually increased from 0.26% to 1.01%. The %T/D ranged from 7.0% to 388.5%, with a mean of 71%. If the lesion with increased uptake is excluded, the range becomes 7.0%-102.1%, with a mean of 50%. Linear regression between the percentage uptake of the diagnostic dose to that of the therapeutic dose results in a slope of 0.42, with a correlation coefficient of only 0.75. We were unable to accurately calculate the radiation dose to the lesion from the diagnostic activity of 131I, because of uncertainty about the tumor mass. CONCLUSION: The percentage uptake of the therapeutic dose is on average only one half of that predicted from the dosimetric uptake in thyroid remnants after surgery, even though the median dosimetric dose was only 40 MBq. This reduced uptake should be accounted for in the therapeutic prescription for thyroid ablation or treatment of residual thyroid cancer. We postulate that this effect is caused by radiation damage from the tracer dose during dosimetry.

Humans↗