PubMed Health⌕ Search

Biomedical subjects

W Y Chung

Publications and source records attributed to W Y Chung.

At least 19 recordsLinked to original sources
PubMed2006

Gain of imprinting of SLC22A18 sense and antisense transcripts in human breast cancer.

The 11p15.5 region harbors three imprinted sense/antisense transcript pairs, SLC22A18/SLC22A18AS, IGF2/IGF2AS (PEG8), and KCNQ1/KCNQ1OT1 (LIT1). SLC22A18 (solute carrier family 22 (organic cation transporter) member 18) and its antisense transcript SLC22A18AS are paternally suppressed in fetal samples. In adult tissue, SLC22A18 displays polymorphic imprinting, but the imprinting status of SLC22A18AS remains elusive. SLC22AI8 DNA-PCR-RFLP analysis using NlaIII restriction digestion identified SLC22A18 heterozygotes within this breast tissue cohort (n = 89). Commercial sequencing identified informative SLC22A18AS samples. Random hexamer-primed cDNA synthesis, SLC22A18/SLC22A18AS-specific PCR, and imprinting evaluation by commercial sequencing demonstrated that SLC22A18AS displays a nonimprinted profile in reduction mastectomies (n = 6). However, SLC22A18 showed a gain of imprinting (GOI) in 1/4 of these normal cases. In the malignant cohort, GOI was also demonstrated in 18% for SLC22A18 and 14% for SLC22A18AS, occurring concomitantly in one case. This study reports the imprinting status of SLC22A18AS in adult tissue, and shows that GOI affects both the sense, and antisense transcripts at this locus in human breast tissue.

Adult↗
PubMed2006

Cystic fibrosis-related diabetes in adults.

We aimed to examine the differences between patients with cystic fibrosis-related diabetes (CFRD), and those with normal glucose handling in adults with cystic fibrosis (CF) in Ireland. We conducted a retrospective analysis of patients who attend the national referral centre for adult CF. Patients were diagnosed as having CFRD by the American Cystic Fibrosis Foundation criteria for diagnosis of CFRD. Of 259 patients, 150 were classifiable and 81 (54%) were classified as having CFRD. The groups with and without CFRD were not significantly different with regard to age (median 28.4 vs 26.0 years), sex (males 56% vs 55%) or BMI (median 20.9 vs 21.3 kg/m2). The group with CFRD had poorer lung function (mean % predicted FEV1 49.9 vs 66.4, P < 0.001), poorer bone mineral density (T-scores at the lumbar spine -1.95 vs -1.44, P < 0.05 and femur -1.19 vs -0.57, P < 0.01) and a greater proportion of PSEUDOMONAS AERUGINOSA positive sputum cultures (82.5% vs 64.2%, P < 0.05). No patients with CFRD carried the R1 17H mutation whilst 19% of the group without CFRD were heterozygous for this defect (P < 0.001). In conclusion, CFRD was highly prevalent in adults. The presence of CFRD was associated with poorer lung function, poorer bone mineral density and an increased prevalence of PSEUDOMONAS AERUGINOSA in sputum. The R1 17H mutation may be protective for CFRD.

Adult↗
PubMed2003

A pilot study of the effects of a behavioural intervention on treatment adherence in HIV-infected patients.

A pilot study was carried out in a group of six HIV-infected non-adherent men testing the effects of a behavioural medication management intervention on adherence with antiretroviral drugs. The study was prospective, using a one-group repeated-measures design. Adherence was measured using two self-reports. The intervention was a behaviourally-based programme that lasted for three months and included individualized education about antiretroviral medication and their side effects; positive reinforcement and encouragement; individualized counselling weekly; follow-up calls; and lifestyle assessment and the identification of adherence barriers. Assessments were carried out at recruitment, immediately after the initiation of the intervention, one month, three months and six months later. Results suggested that the intervention enhanced adherence rates from a mean percentage of 80.27 at baseline to a mean of 97.5% at the end of follow-up (six months time point). Similar improvement was observed in the scores of the scale measuring adherence difficulties. Further, CD4+ counts also slightly improved. Interviews with four of the participants at the end of the study highlighted the problems experienced by patients in taking their medication and supported the usefulness of the intervention. Because of the complexity of the factors behind adherence, it is important that patients are supported with individualized medication management programmes.

Adult↗
PubMed2002

The role of dose distribution gradient in the observed ferric ion diffusion time scale in MRI-Fricke-infused gel dosimetry.

Ferric ion diffusion is a detrimental factor in MRI-Fricke-infused gel dosimetry. In this study, a novel approach involving MR image subtraction and a fast image-based dosimetry technique to study ferric ion diffusion effects is presented. The fast image-based approach allows studying dose profile degradation within minutes post-irradiation. The relationship between the rate of dose profile deterioration and dose distribution gradients can be elucidated with the improved imaging temporal resolution also. Our results showed that for a dose distribution with gradient 4 Gy/mm or higher, ferric ion diffusion causes apparent dose profile degradation in 0.5-1 h post-irradiation. For a gradual dose gradient change of 2.1 Gy/mm or smaller, dose profile degradation appears insignificant for a two-hour elapsed diffusion time. These observations agree well with the theoretical analysis of a square dependence between dose profile degradation and dose distribution gradient. Because all stereotactic radiosurgery procedures produce steep dose distributions and because the ideal "snapshot" of MR scanning cannot be achieved, knowledge of the ferric ion diffusion time scale is important in experimental designs in order to avoid potential measurement errors in MRI-Fricke-agarose gel dosimetry.

Diffusion↗
PubMed2002

A pilot study of the effects of cognitive-behavioral group therapy and peer support/counseling in decreasing psychologic distress and improving quality of life in Chinese patients with symptomatic HIV disease.

Forty-six Chinese patients with symptomatic human immunodeficiency virus (HIV) participated in a comparative study assessing the effectiveness of cognitive-behavioral group therapy (CBT) and peer support/counseling group therapy (PSC) in relation to improving mood and quality of life and decreasing uncertainty in illness as compared to a group receiving routine treatment with no formal psychosocial intervention. The CBT group consisted of 10 subjects, the PSC group of 10 subjects, and the comparison group of 26 subjects. There was a 24% attrition rate. The intervention groups received 12 weekly sessions of therapy over 3 months. Assessment of mood states was carried out before randomization (baseline data), immediately postintervention (3-month time point) and followed-up 3 months later (6-month time point). Assessment of quality of life and uncertainty in illness was carried out before randomization and at the 6-month follow-up time point. Results indicated that the mood of the participants in the CBT group improved in terms of anger, tension-anxiety, depression, confusion, and overall mood. The quality of life in this group was significantly improved compared to the other two groups, as was uncertainty in illness. In the PSC group a worsening of psychologic functioning was observed immediately postintervention, but this picture dramatically improved at the follow-up assessment with improvements of up to 34%. Quality of life also improved over time in this group by almost 5%, but results did not reach statistical significance. This study demonstrated that psychologic interventions could decrease psychologic distress and improve quality of life in symptomatic HIV patients, indicating their use should be incorporated in the management of care of people living with HIV/AIDS.

Adult↗
PubMed2001

[Arterial-switch operation for transposition of the great vessels; good results in the Wilhelmina Children's Hospital, Utrecht, 1977-2000].

OBJECTIVE: To examine the results of the arterial switch operation which is used to correct the transposition of the great arteries. DESIGN: Descriptive. METHOD: In the period May 1977-October 2000 195 patients at the Wilhelmina Children's Hospital in Utrecht, the Netherlands, underwent an arterial switch operation. The patient group consisted of 132 boys and 63 girls, with a median age at surgery of 8 days (range: 0-1976). In accordance with the protocol, the postoperative follow-up consisted of echocardiography and an ECG. Further investigations were performed on indication. Additional data were collected from the status reports. The mean follow-up was 8.0 years (range: 0.04-22.17). RESULTS: The overall peri-operative mortality was 15% (30/195). Initially this figure was about 50%, in the 1980s it was 15% and from 1996 onwards it was 4%. Of the 151 surviving and traceable patients, 2 patients died years later (1.3%). Of the remaining 149 patients, 145 were classified in New York Heart Association class I and 4 in class II. Due to pulmonary stenosis, 45 reinterventions were required in 26 patients (/149; 17%). Left ventricle dysfunction occurred in 5 patients (3%), arrhythmias in 5 patients and aorta abnormalities in 5 patients. Coronary artery abnormalities were found in 5 of the 61 patients who underwent angiography (8%). CONCLUSION: Peri-operative mortality decreased to 4% and late mortality was 1.3%. The long-term clinical outcome of the arterial switch operation was good. Morbidity was predominantly caused by pulmonary stenosis and late coronary obstruction.

Cause of Death↗
PubMed2001

Antioxidative and antitumor promoting effects of [6]-paradol and its homologs.

Recently, considerable attention is focused on anti-carcinogenic phytochemicals, particularly those derived from medicinal or edible plants. [6]-Paradol, a pungent phenolic compound present in certain Zingiberaceae plants, is known to have antimicrobial and analgesic activities. The compound has been reported to attenuate promotion of skin carcinogenesis and TPA-induced ear edema in female ICR mice, and to induce apoptosis in cultured human promyelocytic leukemia (HL-60) cells. In this study, we performed several biochemical studies to evaluate and compare the cancer chemopreventive potential of [6]-paradol and its synthetic derivatives. [6]-Paradol and its synthetic nonpungent analog, [6]-dehydroparadol significantly decreased the incidence and the multiplicity of skin tumors initiated by 7,12-dimethylbenz[a]anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). Topical application of [6]-paradol and its derivatives inhibited TPA-induced ear edema and H(2)O(2) production and myeloperoxidase activity in the dorsal skin of mice. Induction of TPA-induced mouse epidermal ornithine decarboxylase (ODC) activity and H(2)O(2)- and UV-induced formation of oxidized DNA bases in vitro were also attenuated by the above compounds. These results indicate that [6]-paradol and its derivatives possess the cancer chemopreventive potential.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2001

Influence of buffer composition and sample pretreatment on efficiency separation for monitoring neuropeptides in plasma using capillary electrophoresis.

More efficient and faster separation conditions for qualitative as well as quantitative analysis of neuropeptides in human plasma using capillary zone electrophoresis (CZE) have been developed. The analysis method for neuropeptides has been improved specifically to study thyroid hormone related neuropetides for the regulation of thyroid disease. In this study, we investigated the pretreatment methods, composition of the running buffer and rinsing procedures between runs in order to obtain more sensitive and faster separation of trace neuropeptides in plasma by CZE. The tested neuropeptides were somatostatin (SOMA), vasopressin (VP), neurotensin (NT), and thyrotropin-releasing hormone (TRH). Plasma samples were pretreated by deproteinization and solid-phase extraction method. The fraction of neuropeptides was reconstituted in 40% acetonitrile followed by ultrafiltration, and then analyzed by CZE. Resolution and sensitivity was improved using the separation buffer composition with 100 mM Tris-phosphate buffer (pH 2.0) while the sensitivity was further improved via a stacking method using the sample buffer of 40% acetonitrile. These sample pretreatment methods and buffer condition permit quantitative analysis on tested neuropeptides at the 20 ng/mL level. The rinsing procedures between runs using 90% ethanol dramatically shortened the rinsing time to 30 min.

Buffers↗
PubMed2001

Ultrasonographic mass screening for thyroid carcinoma: a study in women scheduled to undergo a breast examination.

This study was carried out to clarify the sensitivity of ultrasonographic mass screening for thyroid carcinoma. Between December 1997 and July 1998, a total of 1401 subjects who were scheduled to undergo either a breast examination or a follow-up examination for breast cancer were enrolled in this study. Patients with thyroid nodules were classified into two groups according to their potential risk for malignancy based on the ultrasonographic findings. Ultrasonographic high-risk patients for thyroid cancer underwent an ultrasound guided fine-needle aspiration biopsy (FNAB) and were advised to undergo a thyroidectomy based on the FNAB results. The characteristics of the thyroid cancer patients detected by mass screening were then compared with those of 106 consecutive female patients with clinical thyroid cancer during the same period. Thyroid nodules were detected in 353 (25.2%) of the subjects, 94 (26.6%) of whom were placed in the high-risk group for thyroid cancer. Among the 94 high-risk patients, 43 underwent a thyroidectomy and 37 turned out to have thyroid carcinomas. The detection rate for thyroid cancer was 2.6% for all subjects. The tumor size was significantly smaller than that of the clinically detected cancer group (P < 0.05). Ultrasonographic mass screening for thyroid carcinoma in women who require breast examinations is thus considered to be effective for the detection of subclinical thyroid carcinoma.

Adolescent↗
PubMed2001

Minimally invasive open thyroidectomy.

We recently developed a new surgical technique for carrying out thyroidectomy, to minimize tissue trauma by obviating unnecessary neck exploration. This report describes our technique of performing minimally invasive open thyroidectomy and compares the results with those of conventional thyroidectomy. Minimally invasive open thyroidectomy was performed by making a small skin incision, 3.0-4.5cm long, and approaching the thyroid directly via a transverse division of the strap muscles without raising skin flaps. The outcomes of 466 patients who underwent a minimally invasive open thyroidectomy were retrospectively compared with those of 437 patients who underwent conventional thyroidectomy for various types of thyroid nodules. There was no significant difference in the extent of surgery between the group of patients who underwent minimally invasive thyroidectomy and the group of patients who underwent conventional thyroidectomy. However, the length of the skin incision, at 3.7 +/- 0.7 vs 9.6 +/- 3.3 cm, respectively, operative time, at 57.6 +/- 11.7 vs 85.2 +/- 32.3 min, respectively, blood loss, at 18.4 +/- 15.3 vs 43.1 +/- 21.8 ml, respectively, and hospital stay, at 1.6 +/- 0.5 vs 4.3 +/- 1.6 days, respectively, were significantly reduced in the minimally invasive open thyroidectomy group (P < 0.05). Moreover, the number of patients who required postoperative analgesia was significantly less in the minimally invasive open thyroidectomy group. These results show that minimally invasive open thyroidectomy provides surgeons with a clear operative field, and that it has proven to be simple, safe, and practical for selected patients.

Adult↗
PubMed2001

Plasma ascorbic acid: measurement, stability and clinical utility revisited.

AIMS: To compare plasma ascorbic acid results by the colorimetric FRASC (Ferric Reducing/Antioxidant and Ascorbic Acid) assay and a reference HPLC method; to re-examine plasma ascorbic acid stability, and anticoagulant effect. DESIGN AND METHODS: For method comparison, 31 plasma samples were tested by both methods. For stability, matching EDTA, heparin, citrate and fluoride/oxalate plasma, stored under different conditions of time and temperature, was measured. RESULTS: FRASC is an acceptable alternative to HPLC for plasma ascorbic acid: precision, limit of detection and recovery were similar, and results by the two methods were indistinguishable: mean (95% CI) difference:1.8 (-1.1-4.6; n = 31) micromol/L. Ascorbic acid was most stable in heparinized plasma. Marked loss (p < 0.05) in EDTA plasma occurred within 30 min of blood collection. CONCLUSIONS: FRASC offers a speedy and reliable alternative to HPLC for plasma ascorbic acid. Heparin is proposed as the anticoagulant of choice; loss of ascorbic acid is rapid in EDTA plasma ex vivo.

Adult↗
PubMed2001

Magnetic resonance imaging of reconstructed anterior cruciate ligament.

After anterior cruciate ligament reconstruction with autologous patellar tendon, 23 patients who had clinically stable knees were studied prospectively with sequential magnetic resonance imaging 1, 2, 3, 6, and 12 months after surgery. The images of the anterior cruciate ligament were obtained with a 1.5 tesla magnetic resonance scanner in the oblique sagittal, coronal, and oblique axial planes. The cross-sectional area and signal intensity on the reconstructed anterior cruciate ligament were measured in an oblique axial image. The usefulness of the oblique axial image in evaluating the integrity of the reconstructed anterior cruciate ligament was seen. The result showed that the diameter of the graft increased by 70% of its initial size and the signal intensity of the reconstructed graft also showed a tendency to increase. In three patients, there was discontinuity in the graft direction on the oblique sagittal image, but on the oblique axial image there was no evidence of reconstructed anterior cruciate ligament rupture in the sequential images. This shows the value of the oblique axial image in evaluating the integrity of the reconstructed anterior cruciate ligament. Also, sufficient notchplasty in anterior cruciate ligament reconstruction may be needed to prevent graft impingement.

Adolescent↗
PubMed2001

Characteristics of silicon nitride after O2 plasma surface treatment for pH-ISFET applications.

Silicon nitride (Si3N4) sensing gate pH-ion-selective field effect transistors (ISFETs) were treated by 2.54-GHz microwave O2 plasma, the results show the ISFET sensitivity has an advantage up to 24% increment after the plasma treatment. Electron spectroscopy for chemical analysis (ESCA) is used to make sure that the plasma treatment is not just a native oxide cleaning procedure. The samples, which were immobilized with glutaraldehyde used as a bifunctional reagent and 3-aminopropyItriethoxysilane used as an adhesion promoter were studied. The binding force between the glucose oxidase and glutaraldehyde immobilized samples, and the element concentrations of nitrogen in 3-aminopropyltriethoxysilane immobilized samples are higher which were treated by plasma.

Glucose Oxidase↗
PubMed2001

Extraovarian granulosa cell tumor.

A 54-year-old woman was admitted to our hospital complaining of postcoital bleeding. Sonography of the abdomen showed a 8.2 x 8.9 cm-sized solid heterogeneous mass occupying the cul-de-sac, which appeared to be in no way connected with the ovary. On exploratory laparotomy, the tumor mass protruded from the posterolateral retroperitoneum of the pelvic cavity and severely replaced the uterus and adnexa with the outer surface being grossly intact. It grossly measured 10 cm in maximal diameter. The histologic features closely resembled those of ovarian granulosa cell tumor. The primary extraovarian granulosa cell tumor is extremely rare such that in the English literature only 7 cases have been reported to date. Of those granulosa cell tumors are especially rare and only two cases have been reported to arise from retroperitoneum. We herein present a case of retroperitoneal granulosa cell tumor with special regard to differential diagnosis from other solid tumors with similar histology.

Diagnosis, Differential↗
PubMed2001

A metastatic pituitary carcinoid tumor successfully treated with gamma knife radiosurgery.

Intracranial metastasis occurs in a certain number of patients with carcinoid tumor. However, carcinoid tumor with metastasis to the pituitary gland is extremely rare. Up to the present, no effective treatment for either a metastatic intracranial carcinoid tumor or a metastatic pituitary lesion of any origin has been documented. We have treated a case of metastatic carcinoid tumor of the pituitary gland with transsphenoidal tumor resection followed by gamma knife radiosurgery. A 59-year-old man presented with headache and left oculomotor palsy. He was treated at the same hospital for bronchial atypical carcinoid tumor one and a half years ago. Magnetic resonance image of the brain showed a pituitary tumor. There were no signs of recurrent or metastatic lesion elsewhere despite thorough investigation. Transsphenoidal approach for removal of tumor was done and the pathology turned out to be a metastatic carcinoid tumor. Subsequent gamma knife radiosurgery was given for residual tumor. The oculomotor palsy improved after radiosurgery. No neurological deficit occurred. Follow-up CT scan of the brain showed complete resolution of the tumor. We concluded that gamma knife radiosurgery could be used to treat a metastatic intracranial carcinoid tumor. It can also be used to treat a metastatic lesion of the pituitary gland without causing neurological deficit.

Carcinoid Tumor↗
PubMed2001

Water-soluble antioxidants in human tears: effect of the collection method.

PURPOSE: To resolve differences in published data on tear antioxidant levels by comparing the concentration of water-soluble antioxidants in human reflex tears collected by capillary tube and by the Schirmer strip collection method and in basal and reflex tears collected using the Schirmer strip method. METHODS: Yawn-induced reflex tears (collected simultaneously by capillary tubes and by Schirmer strips) and basal tears (by Schirmer strips and using local anesthetic) were collected from 12 healthy subjects. Tear cysteine, ascorbate, glutathione, urate, and tyrosine were measured by high-performance liquid chromatography within a few minutes of collection. RESULTS: Cysteine, ascorbate, glutathione, and tyrosine were 5 to 10 times higher (P < 0.01) in both reflex and basal tears collected by Schirmer strip compared with reflex tears collected by capillary tube from the same subject. Urate levels were slightly but nonsignificantly higher in Schirmer strip samples (P > 0.05). CONCLUSIONS: The conflict in published data on tear antioxidants is caused by differences in collection methods. With the exception of urate, antioxidants accumulate to very high levels in corneal cells. Spuriously high antioxidant levels in tears collected using Schirmer strips, therefore, are most probably caused by contamination with intracellular constituents. The capillary tube collection method is proposed as the method of choice for reflex tear collection for biochemical studies. This less-invasive method facilitates the evaluation of tear antioxidant levels as a biomonitoring tool for corneal health. Although moderately increased antioxidant levels may be beneficial, the authors hypothesize that marked increases may indicate damage to the ocular surface.

Adult↗