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Wan-Yu Lin

Publications and source records attributed to Wan-Yu Lin.

At least 19 recordsLinked to original sources
PubMed2007

Robust multipoint simultaneous identical-by-descent mapping for two linked loci.

A challenging issue in genetic mapping of complex human diseases is localizing disease susceptibility genes when the genetic effects are small to moderate. There are greater complexities when multiple loci are linked to a chromosomal region. Liang et al. [Hum Hered 2001;51:64-78] proposed a robust multipoint method that can simultaneously estimate both the position of a trait locus and its effect on disease status by using affected sib pairs (ASPs). Based on the framework of generalized estimating equations (GEEs), the estimate and standard error of the position of a trait locus are robust to different genetic models. To utilize other relative pairs collected in pedigree data, Schaid et al. [Am J Hum Genet 2005;76:128-138] extended Liang's method to various types of affected relative pairs (ARPs) by two approaches: unconstrained and constrained methods. However, the above methods are limited to situations in which only one trait locus exists on the chromosome of interest. The mean functions are no longer correctly specified when there are multiple causative loci linked to a chromosomal region. To overcome this, Biernacka et al. [Genet Epidemiol 2005;28:33-47] considered the multipoint methods for ASPs to allow for two linked disease genes. We further generalize the approach to cover other types of ARPs. To reflect realistic situations for complex human diseases, we set modest sizes of genetic effects in our simulation. Our results suggest that several hundred independent pedigrees are needed, and markers with high information, to provide reliable estimates of trait locus positions and their confidence intervals. Bootstrap resampling can correct the downward bias of the robust variance for location estimates. These methods are applied to a prostate cancer linkage study on chromosome 20 and compared with the results for the one-locus model [Am J Hum Genet 2005;76:128-138]. We have implemented the multipoint IBD mapping for one and two linked loci in our software GEEARP, which allows analyses for five general types of ARPs.

Bias↗
PubMed2006

Development of a new method for small bowel transit study.

BACKGROUND AND PURPOSE: Currently, most studies combine the small bowel transit examination with gastric emptying time examination. There are significant drawbacks to this method. The radiotracer does not enter the small intestine in a bolus and the starting time for transit in the duodenum is difficult to define. This makes the result unreliable. In this study, we used a commercial enteric capsule containing radioactive charcoal to solve these problems. MATERIALS AND METHODS: Activated charcoal powder was mixed with Tc-99m pertechnetate and loaded to the enteric capsule which can resist gastric acid and dissolve only in the small intestine. In-vitro stability experiment was performed by immersing these capsules in a colorless phosphate buffer of variable pH which mimicked the condition in stomach and small intestine. In addition, ten healthy Chinese volunteers were included for in-vivo experiment. Anterior and posterior views of abdomen were obtained at regular 30-minute intervals until the eighth hour after administration of the radioactive enteric capsule. Small bowel transit time was calculated. RESULTS: The enteric capsule remained intact for at least 480 minutes in the solution mimicking gastric content (pH = 3.0) and disrupted at a mean duration of 227.2 minutes at a pH of 6.8 and at a mean duration of 212.4 minutes at a pH of 7.4 in the solution mimicking pancreaticobiliary secretions. In nine of ten volunteers, the small bowel transit time was between 30 to 270 minutes with a mean transit time of 140 min. In one volunteer, we failed to detect the exact time of small bowel transit because the capsule remained in the stomach throughout the study for up to 8 hours. CONCLUSIONS: We consider activated charcoal labeled with Tc-99m pertechnetate using an enteric capsule as the carrier to be a potential radioactive marker for small bowel transit study.

Administration, Oral↗
PubMed2006

Calyceal diverticulum in FDG-PET imaging.

A 46-year-old female underwent a fluorodeoxyglucose F-18 (FDG) positron emission tomography (PET) whole-body scan for tumor screening after showing no symptoms or signs. The PET images showed a large FDG-avid lesion in the left renal pelvis, with a maximum standard uptake value (SUV) of 10.7 at 1 hour and 3.9 at 3 hours. An abdominal computed tomography (CT) scan showed a 3.7-cm cystic lesion with a slightly irregular wall in the left kidney. The immediate impression was that of a complicated cyst. A histopathologic report after surgery confirmed a calyceal diverticulum. To the best of our knowledge, this is the first report of FDG uptake in a case of calyceal diverticulum.

Diverticulum↗
PubMed2006

Jejunal tuberculosis: incidental finding on an FDG-PET scan.

A 32-year-old male had suffered from persistent dull epigastric pain, constipation, postprandial vomiting, and body-weight loss for 2 months. An abdominal computed tomography (CT) scan showed thickening of the proximal jejunal wall. He was also referred to our center for an fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) scan because his tumor marker CA19-9 was above 800 ng/mL and malignancy was suspected. The PET scan showed an FDG-avid lesion over the upper left abdomen. Endoscopy of the small intestine revealed focal thickening of the mucosal fold and skip ulcer lesions in the jejunum. Culture from the biopsy tissue proved the diagnosis of Mycobacterium tuberculosis infection. No evidence of pulmonary tuberculosis was detected during further evaluation.

Adult↗
PubMed2006

Effectiveness of delayed 2-day lymphoscintigraphy on sentinel lymph node detection in patients with breast cancer with negative early lymphoscintigraphy.

PURPOSE: Most centers perform lymphoscintigraphy for the detection of sentinel lymph node (SLN) in patients with breast cancer within 2 hours after radiotracer injection. However, the interval between the injection of the radiotracer and surgery may not be long enough. In this study, we evaluated the effectiveness of delayed imaging (more than 15 hours) for SLN detection in patients with negative early images. METHODS: We retrospectively analyzed a database of 401 patients with breast cancer referred for SLN detection. On the day before surgery, lymphoscintigrams were obtained at 30-minute intervals until SLN was detected or 120 minutes. In those patients who failed to localize SLN on the early images, delayed imaging was performed the next morning. RESULTS: Twenty-seven (6.7%) patients failed to show SLN on the early images. In the 27 patients, delayed imaging was available for 14 patients but not for 13 patients resulting from the tight time schedule for surgery. Of the 14 patients with delayed images, SLNs were successfully harvested in 10 patients (71.4%) at surgery. In contrast, in the 13 patients who lacked delayed images, SLN was only harvested in one case (7.7%) at surgery. The intraoperative detection rate for SLN was significantly higher in the 14 patients with delayed images than that in the 13 patients without delayed images. CONCLUSIONS: Two-day delayed imaging is significantly useful to increase the rate of localizing SLN at surgery in patients with a negative early image.

Breast Neoplasms↗
PubMed2006

A comparison of biodistribution between 111In-DTPA octreotide and 111In-DOTATOC in rats bearing pancreatic tumors.

111In-DTPA octreotide (DTPAOC) has been used for detecting somatostatin receptor positive tumor for years. In-111 DOTA-Tyr3-octreotide (DOTATOC) is newly developed for diagnostic and therapeutic purposes. In this study, we compared the biodistribution and tumor uptake ratio after injection of In-111 DTPAOC and In-111 DOTATOC in rats. Twelve rats bearing pancreatic tumors were divided into two groups: six rats were sacrificed at 4 hr after injection of 3.7 MBq of In-111 DTPAOC and another 6 rats were sacrificed at the same time after injection of 3.7 MBq of In-111 DOTATOC. Samples of various organs were obtained and counted to calculate the tissue concentration. In addition, 12 rats bearing pancreatic tumors were scanned at 4, 24, and 48 hr after injection of 37 MBq of In-111 DTPAOC or In-111 DOTATOC. The tumor uptake ratios (T/N ratio) were calculated. The biodistribution data showed that the activity in the tumor as well as in the kidney was significantly higher in the In-111 DOTATOC group than in the In-111 DTPAOC group, although both radiopharmaceuticals had the expected high affinity to the tumor. The T/N ratios in the In-111 DOTATOC group were also significantly higher than those in the In-111 DTPAOC group at 24 hr after injection. We conclude that In-111 DOTATOC showed lower clearance than In-111 DTPAOC in the rats bearing pancreatic tumors, although both of these radiopharmaceuticals showed expected high tumor uptake.

Animals↗
PubMed2005

Tc-99m(V)-DMSA in wound infection after closure of an ileostomy.

We present a 71-year-old man who underwent closure of an ileostomy and had a fever seven days post surgery. Both Tc-99m(V)-dimercaptosuccinic acid (DMSA) and gallium-67 citrate scans showed increased tracer accumulation in the right lower quadrant of the abdomen. Tc-99m(V)-DMSA scintigraphy can be a rapid alternative tool in the detection of wound infection in patients after ileostomy closure.

Aged↗
PubMed2005

Value of delayed 18F-FDG-PET imaging in the detection of hepatocellular carcinoma.

BACKGROUND: 18F-Fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) is a very useful imaging technique and is the best modality for the evaluation of many kinds of tumour. However, in the evaluation of hepatocellular carcinoma (HCC), the diagnostic accuracy of routine 60 min static imaging is not satisfactory. Some authors have suggested that delayed 2 h imaging is a better 18F-FDG-PET protocol for tumour detection. However, the value of delayed 3 h imaging has not been clarified. In this study, we performed delayed 2 h and 3 h imaging on patients with HCC and compared their diagnostic accuracy with standard 60 min imaging. METHODS: Twelve patients with HCC were enrolled in this study. Of these 12 patients, four had not been treated and eight had received transcatheter arterial embolization (TAE) therapy for more than 4 months before the PET study. One hour after injection of 18F-FDG, a whole-body scan was performed. In addition, delayed imaging focusing on the liver was also performed 2 h and 3 h after the injection. The standard uptake value (SUV) was calculated for the tumours in each image. RESULTS: The twelve patients had 16 HCCs. Of the 16 HCCs, nine were detected by 18F-FDG-PET scans based on the 1 h images, whereas 10 HCCs were detected based on the 2 or 3 h images. The diagnostic sensitivity increased from 56.3% on the 1 h image to 62.5% on the 2 and 3 h images. In addition, the mean SUV increased from 3.63 at 1 h to 3.86 at 2 h and 3.99 at 3 h after the injection of 18F-FDG. On the other hand, the mean SUV in the normal liver tissue decreased slightly from 2.38 at 1 h to 2.33 at 2 h and 2.31 at 3 h. The tumour to normal liver tissue (T/N) ratio increased from 1.56 at 1 h to 1.68 at 2 h and 1.75 at 3 h. CONCLUSION: In the evaluation of HCC, delayed 2 and 3 h imaging can detect more lesions than standard 1 h imaging. Imaging at 3 h has a better T/N ratio than imaging at 2 h, but does not increase the diagnostic sensitivity.

Adult↗
PubMed2005

FDG-PET findings in barium aspiration.

A 47-year-old man had nasopharyngeal carcinoma (NPC). He received radiotherapy 10 years ago and was cancer-free after the treatment. However, diplopia occurred 1 year ago and became more progressive recently. An FDG-PET scan was performed to rule out the possibility of recurrence. No abnormal FDG uptake was demonstrated in the head and neck. However, an irregular area of increased FDG uptake was noted in the right lower lung. The plain chest x-ray showed barium retention in the same area, which might have resulted from aspiration of barium during gastrointestinal barium examination 2 years ago. A follow-up chest x-ray showed no apparent change and there was no evidence of metastases in the lung 6 months later.

Artifacts↗
PubMed2005

Extraordinarily high F-18 FDG uptake caused by radiation necrosis in a patient with nasopharyngeal carcinoma.

A false-positive F-18 FDG PET scan caused by osteoradionecrosis and inflammation in patients with nasopharyngeal carcinoma (NPC) has been reported. The standard uptake values (SUVs) in these false-positive cases are always below 6 and decrease with time. This report is concerned with a false-positive result with extraordinarily high F-18 FDG uptake, which increased on the delayed 3-hour image. A 63-year-old man with NPC underwent surgical removal and radiotherapy (7400 cGy) in July 2003. In October 2003, the CT scan showed a large soft tissue mass over the nasopharynx. Tumor recurrence was suspected. F-18 FDG PET scan showed an FDG-avid lesion over the nasopharyngeal region with a maximum SUV of 28.8 at 1 hour that increased to 30.4 at 3 hours. Biopsy was performed and the histopathologic examination showed only necrotic tissue and no evidence of tumor cells. Radiation necrosis was diagnosed. No evidence of tumor recurrence was noted during the 10-month follow-up period.

Carcinoma↗
PubMed2005

A pitfall of FDG-PET image interpretation: accumulation of FDG in the dependent area of the urinary bladder after bladder irrigation--the usefulness of the prone position.

In F-18 FDG PET studies, retrograde irrigation of the urinary bladder is usually used to reduce the interference with physiological urinary accumulation of F-18 FDG in patients with possible pelvic lesions. A 34-year-old female who had recently been diagnosed with cervical cancer had an F-18 FDG-PET scan performed for whole-body evaluation. The bladder was irrigated with physiological saline and filled with 200 mL of irrigation fluid through a 3-way balloon catheter inserted before the scan. Two areas with high FDG accumulation were noted in the posterior pelvis. Tumor invasion or metastasis could not be ruled out. Additional focal imaging of the pelvis was performed with the patient in the prone position. The lesion on the left side of the patient was still noted, whereas the lesion on the right had disappeared, which proved that it was a false-positive lesion. Great caution is required when assessing imaging results to avoid misdiagnosis in patients after bladder irrigation.

Adult↗
PubMed2005

Hyperglycemia with occipital seizures: images and visual evoked potentials.

PURPOSE: Hyperglycemia may rarely be seen with visual seizures. Observation of both visual evoked potentials (VEPs) and magnetic resonance imaging (MRI) in visual status epilepticus (SE) has not been reported. We describe acute and follow-up VEP and MRI findings of a patient with hyperglycemia-related visual SE of occipital origin. METHODS: In a 59-year-old diabetic woman, complex visual hallucinations and illusions developed with < or =10 seizures per hour as an initial manifestation of nonketotic hyperglycemia. RESULTS: Neurologic examination revealed ictal nystagmus to the right and continuous right hemianopsia. Ictal electroencephalography (EEG) and Tc-99m hexamethylpropylene amine oxime (HMPAO) single-photon emission computed tomography (SPECT) revealed an epileptogenic focus in the left occipital lobe. MRI with fluid-attenuated inversion recovery showed focal subcortical hypointensity and gyral hyperintensity. Follow-up MRI showed only minimal gyral hyperintensity at 6 months. The P100 amplitude of VEP was significantly higher at the right occipital area during SE, but slightly higher on the left after the patient had been seizure free for 6 months. CONCLUSIONS: Occipital seizures and hemianopsia can be caused by hyperglycemia and may be accompanied by special MRI and VEP findings.

Electroencephalography↗
PubMed2005

Comparison of animal models with soft tissue infection by different bacilli.

In clinical medicine improved diagnostic methods for the detection of infection are needed. A good infectious animal model is very important for the development of a new diagnostic method or drug. The purpose of this study was to establish a good animal model with soft tissue infection. Twenty-four SD rats were divided into four groups (6 in each group). Various bacilli including Staphylococcus aureus (S. aureus), Streptococcus pneumoniae (S. pneumoniae), and Escherichia coli (E. coli) were injected intramuscularly into the left caudal thighs of three groups of rats to create soft tissue infection. In addition, normal saline was injected into the left caudal thighs of ten rats which were used as controls. Before and 48 hr after inoculation of the bacilli, a blood sample (0.5 ml) was taken from each rat and analyzed to determine the white blood cell count and differentiated cell count. In addition, 48 hr after the inoculation, 0.2 mCi of gallium-67 was injected via the tail vein. Gallium scan was performed at 24 hr and 48 hr after administration of the radiotracer. The dorsal view of both hind legs was imaged and analyzed by computers to calculate the lesion-to-normal (L/N) ratio. After imaging, all rats were sacrificed and specimens from portions of the infected thigh muscle were sent for histopathologic investigation to confirm the infection. The increase in both the WBC counts and the segmented polymorphonuclear leukocytes (PMNs) were most significant in the S. aureus group, followed by the S. pneumoniae group, E. coli group and normal control groups. The rats with S. aureus infection had significant gallium uptake at the site of infection and the highest L/N ratio of 2.14 on the 24-hr image and 2.0 on the 48-hr image. The rats with S. pneumoniae had the second highest L/N ratio (1.41 at 24 hr, and 1.48 at 48 hr). The L/N ratio for the E. coli group was 1.27 at 24 hr and 1.35 at 48 hr. No obviously abnormal gallium uptake was demonstrated in the normal controls. We conclude that all three bacilli induced a soft tissue infection in SD rats. S. aureus resulted in the most significant infectious signs.

Animals↗
PubMed2004

Decreased uptake after fractionated ablative doses of iodine-131.

PURPOSE: In an attempt to obviate the necessity for hospitalisation, the ablative dose of 131I in the treatment of thyroid cancer is divided into two or three fractions at weekly intervals in some hospitals with no special bed for 131I treatment. Thyroid stunning has been observed in patients receiving a 131I dose between 74 and 370 MBq (2-10 mCi). However, the influence of 131I uptake after administration of a higher dose, such as 1,110-1,850 MBq of 131I, has never been reported. In this study, we evaluated the degree of reduction in 131I uptake after patients received 1,480 MBq of 131I and evaluated the clinical value of fractionated ablative doses of 131I. METHODS: Thirty-five patients with functional thyroid cancer received a total of 4,440 MBq (120 mCi) of 131I which was divided into three fractions administered at weekly intervals. In all patients two 131I whole-body scans were performed. The first scan was performed directly prior to the second dose of 131I (7 days after the first administration of 131I), and the second scan was performed 7 days after the second administration of 131I and directly prior to the third administration. Regions of interest including the neck and lungs were drawn to calculate the uptake of 131I in the thyroid remnant and possible cervical lymph node and lung metastases. RESULTS: The mean uptake of 131I was 2.73% 7 days after the first administration, and decreased significantly to 0.26% 7 days after the second administration. The mean decrease was as high as 80.7%. The decrease in 131I uptake was significant in all patients except the two with lung metastases. In the two patients with lung metastases, no definite evidence of decreased uptake was noted; the uptake of 131I in the lung metastases even increased on the second 131I image in one of these patients. After administration of 1,480 MBq of 131I, the decreased uptake was significant in all neck lesions but not in lung metastases. CONCLUSION: The use of fractionated ablative doses of 131I is not to be recommended in patients without lung metastases. However, the influence of fractionated ablative doses of 131I in patients with lung metastases is worthy of further study.

Adult↗
PubMed2004

Preparation and biodistribution of rhenium-188 ECD/Lipiodol in rats following hepatic arterial injection.

Radiolabeled Lipiodol has routinely been used in hepatoma therapy. In this article an attempt to develop a new (188)Re-ECD/Lipiodol radiopharmaceutical, in which the chelating agent ECD (ethyl cyteinate dimer), is the constituent of the known brain perfusion agent (99m)Tc-ECD, and an evaluation of its stability and biodistribution in rats with hepatic tumors is presented. First, (188)Re-ECD was prepared in a vial, followed by extraction with Lipiodol to get the final product, (188)Re-ECD/Lipiodol. The optimal labeling conditions for (188)Re-ECD were: (1) tartaric acid which is better than EDTA as a weak chelating agent; and (2) 15 mg of SnCl(2), as the reducing agent, and 5-10 mg of tartaric acid in each vial had a better labeling yield. The radiochemical purity of (188)Re-ECD/Lipiodol was more than 94%. Twenty-four male Sprague-Dawley rats with liver tumors were sacrificed at 1, 24, and 48 h (eight rats each time) after an injection of approximately 7.4 MBq of (188)Re-ECD/Lipiodol via the hepatic artery. The radioactivity in the liver tumor is significantly high following therapeutic arterial injection, and relatively low in other organs including the bone, spleen, brain, thyroid, stomach, muscle, blood, and testis throughout this study. In conclusion, the new preparation of (188)Re-ECD/Lipiodol is a candidate agent for the treatment of liver cancer.

Animals↗
PubMed2003

Gallium-67 activated charcoal: a new method for preparation of radioactive capsules for colonic transit study.

Indium-111 is currently the radionuclide of choice for colonic transit study. However, it is expensive and not available in many hospitals. Technetium-99m has been proposed for colonic transit study but the short half-life has limited its use. Gallium-67 citrate is inexpensive and available in most countries. Most importantly, it has a suitable half-life for colonic transit study. Attempts have been made in some studies to use (67)Ga citrate to label activated charcoal, but the results have not been good because of poor stability. In this study, we successfully labelled activated charcoal()with (67)Ga citrate by adding alcohol and 5% glucose solution. To evaluate the in vitro stability, the (67)Ga-activated charcoal was incubated in a milieu mimicking the intestinal content, containing lipase, trypsin and glycochenodeoxycholate at different pH values (6.0, 7.0, 7.4 and 8.0) and for different durations (0 h, 24 h, 48 h, 72 h and 96 h). For the in vivo study, the (67)Ga-activated charcoal was loaded into a commercial empty enteric capsule. Colonic transit scintigraphy was performed in five volunteers, including three healthy people and two constipated patients, after intake of the radioactive capsule. Images were obtained at 2 h, 4 h, 6 h, 8 h, 24h, 48 h, 72 h etc. until no radioactivity was detected in the bowel. Our data show that the in vitro stability of (67)Ga-activated charcoal was good. The labelling efficiency still exceeded 91% at 96 h at pH values of 6.0, 7.0 and 7.4. In the group with a pH value of 8.0, the labelling efficiency gradually fell during the 4-day incubation but was still higher than 88% at the end of the fourth day. In the in vivo study, most capsules disintegrated in the caecum/colon region, and the (67)Ga-activated charcoal mixed very well with bowel content. In addition, the radioactive charcoal could be detected clearly on the 72-h image, which is very important for the evaluation of colonic transit time in patients with constipation. In conclusion, activated charcoal labelled with (67)Ga citrate is a potential radioactive marker for colonic transit study.

Capsules↗
PubMed2003

Pedal Tc-99m phytate lymphoscintigraphy in primary chylopericardium.

This paper describes a case of 65-year-old woman with primary chylopericardium. She received Tc-99m phytate lymphoscintigraphy after pericardial drainage and was managed with medium-chain triglycerides without surgical intervention. This was the first reported case of primary chylopericardium diagnosed with Tc-99m phytate lymphoscintigraphy.

Aged↗