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Biomedical subjects

W Aung

Publications and source records attributed to W Aung.

12 recordsLinked to original sources
PubMed2004

Smooth muscle tumour of the pharynx: a rare tumour presenting with globus pharyngeus symptoms.

A rare case of a smooth muscle tumour in the pharynx is reported, together with histopathological findings. The patient's psychiatric background and recurrent complaint of a sensation of a lump in the throat all pointed to a psychogenic aetiology, and diagnosis was delayed. The importance of mirror or endoscopic examination of the pharynx is stressed in patients with globus pharyngeus symptoms.

Conversion Disorder↗
PubMed2001

Study of quantitative oral radioactivity in salivary gland scintigraphy and determination of the clinical stage of Sjögren's syndrome.

UNLABELLED: In this study, the oral radioactivity seen in salivary gland scintigraphy, which was established entirely on the basis of radioactive saliva secreted by the parotid and submandibular glands, was evaluated quantitatively in healthy volunteers and in patients with Sjögren's syndrome. METHODS: Salivary gland scintigraphy and labial biopsy were performed on 70 patients with Sjögren's syndrome. After intravenous administration of 99mTc-sodium pertechnetate, dynamic scintigraphy was performed and time-activity curves for the oral cavity and four major salivary glands were generated. Lemon juice stimulation was delivered at 40 min. The prestimulatory oral activity index, poststimulatory oral activity index, and time interval between the vascular perfusion peak and the prestimulated maximum oral activity point were calculated to quantify the oral activity. Other glandular functional parameters-namely, maximum accumulation (MA), maximum secretion, secretion velocity, time at maximum count, time interval from stimulation to minimum count, and uptake ratio (UR) of the parotid and submandibular glands-were also calculated. Salivary gland scintigraphy was also performed on 21 healthy subjects with no evidence of salivary gland malfunction. RESULTS: Histopathologic grade 1 or 2 was found in 29 patients and grade 3 or 4 was found in 41 patients, and they were regarded as being in the early and advanced stages of Sjögren's syndrome, respectively. After overall analysis, all of the oral activity indices and the MA and UR of the submandibular gland clearly decreased as clinical severity progressed, and statistically significant differences were observed. CONCLUSION: New oral activity indices correlated with the stage of Sjögren's syndrome, and these quantitative oral indices together with certain glandular parameters (mainly MA and UR of the submandibular gland) were found to be sensitive enough to distinguish the disease severity of Sjögren's syndrome.

Biopsy↗
PubMed2001

Antiapoptotic activity is dispensable for insulin-like growth factor I receptor-mediated clonogenic radioresistance after gamma-irradiation.

PURPOSE: The purpose of this study was to evaluate the relationship between apoptotic activity and clonogenic radiosensitivity in vitro using an insulin-like growth factor I receptor (IGF-IR) signaling model, which is known to exert tumorigenic and antiapoptotic effects. EXPERIMENTAL DESIGN: We used mouse embryo fibroblast cell lines expressing either human IGF-IR [R+(Wt) and R+] or the marker gene alone [R-(puro)]; these cell lines were derived from R- cells, which are deficient in IGF-IR. After gamma-irradiation, apoptotic activity was determined by the presence of DNA fragmentation and caspase-3-, -8-, and -9-like activities. Clonogenic radiosensitivity was determined by a colony-forming assay. RESULTS: R+(Wt) and R+ cells expressed similar levels of IGF-IR, transducing phosphorylation signals to major downstream substrates on insulin-like growth factor I stimulation. R+ cells were resistant to the induction of apoptosis after gamma-irradiation; however, both R+(Wt) and R-(puro) cells demonstrated significant DNA fragmentation and increase in caspase-3-, -8-, and -9-like activities. Both R+(Wt) and R+ cells were radioresistant (to a similar extent) compared with R-(puro) cells as measured by a colony-forming assay. Clonogenic radioresistance was not influenced by the inhibition of Akt/protein kinase B through treatment with wortmannin at low concentrations specifically inhibiting phosphatidylinositol 3'-kinase. CONCLUSIONS: Our findings indicate that apoptotic activity does not necessarily predict clonogenic survival after exposure to ionizing radiation. This study provides clinical implications in the evaluation of apoptotic activities observed during the course of radiotherapy to predict accurate tumor response or local control.

Androstadienes↗
PubMed2000

Comparison of lung perfusion scintigraphic findings in pulmonary thromboembolism in systemic lupus erythematosus, SLE plus antiphospholipid syndrome, and primary antiphospholipid syndrome.

In this study, we compared and reviewed the findings on lung perfusion scans performed in patients with systemic lupus erythematosus (SLE), systemic lupus erythematosus with associated antiphospholipid syndrome (SLE + APS), and primary antiphospholipid syndrome (PAPS), to evaluate the prevalence of pulmonary embolism in restricted samples of the patient groups. Lung perfusion scintigraphy with 99Tc(m)-macroaggregated albumin was performed in 31 patients (SLE = 7; SLE + APS = 14; PAPS = 10). The seven patients with SLE alone and the 10 patients with PAPS had normal perfusion lung scans. Six of the 14 SLE + APS patients showed a segmental uptake defect on multi-view perfusion scans. Thus, the SLE + APS patients were found to have a higher risk of pulmonary thromboembolism than the SLE alone and primary APS patients (P<0.05). The results of our study suggest that lung perfusion scintigraphy should be performed routinely in these patients, even in the absence of pulmonary clinical manifestations, to obtain baseline data for disease outcome and management.

Adult↗
PubMed2000

Sjögren's syndrome: comparison of assessments with quantitative salivary gland scintigraphy and contrast sialography.

UNLABELLED: This study compared the quantitative parameters of salivary gland scintigraphy and the sialographic stages in patients with Sjögren's syndrome. METHODS: One hundred sixteen patients suspected of having Sjögren's syndrome were examined with salivary gland scintigraphy and contrast sialography. When contrast sialography was used as the gold standard, Sjögren's syndrome was diagnosed in 50 of these 116 patients; Sjögren's syndrome was not seen in the other 66 patients. After injection of 370 MBq 99mTc-sodium pertechnetate, dynamic salivary gland scintigraphy with lemon juice stimulation was performed for 50 min. Functional parameters for the parotid and submandibular glands were calculated, and scintigraphic and sialographic results were compared. RESULTS: With the progression of sialographic stages from 0 to 4, the quantity of tracer accumulation decreased in the submandibular gland (P < 0.0001), and the quantity of tracer secretion decreased in the parotid gland (P < 0.0001). The sialographic stage in patients with Sjögren's syndrome was correlated with these scintigraphic parameters (P < 0.0001): sialographic stage = 3.243 - 0.337 x (submandibular gland uptake ratio) - 0.026 x (parotid gland maximum secretion). CONCLUSION: The decreased accumulation in the submandibular gland and the decreased secretion in the parotid gland were highly sensitive indicators of salivary gland disease in Sjögren's syndrome. The sialographic stage was correlated with these scintigraphic parameters.

Adult↗
PubMed1999

Diffusion coefficients in abdominal organs and hepatic lesions: evaluation with intravoxel incoherent motion echo-planar MR imaging.

PURPOSE: To determine the true diffusion coefficients of abdominal organs and hepatic lesions with intravoxel incoherent motion (IVIM) echo-planar magnetic resonance (MR) imaging. MATERIALS AND METHODS: Seventy-eight patients suspected of having hepatic lesions were examined with IVIM echo-planar MR imaging at 1.5 T. There were 77 hepatic masses (27 hepatocellular carcinomas, 10 metastatic tumors, eight hemangiomas, and 32 cysts) in the 78 patients. The true diffusion coefficient D and the perfusion fraction f were calculated and compared with the apparent diffusion coefficient (ADC). RESULTS: Specific values of D were found for abdominal organs (liver, 0.72 x 10(-3) mm2/sec; spleen, 0.80 x 10(-3) mm2/sec; kidney, 1.38 x 10(-3) mm2/sec; gallbladder, 2.82 x 10(-3) mm2/sec) and for hepatic lesions (hepatocellular carcinoma, 1.02 x 10(-3) mm2/sec; metastasis, 1.16 x 10(-3) mm2/sec; hemangioma, 1.31 x 10(-3) mm2/sec; cysts, 3.03 x 10(-3) mm2/sec). The ADCs of solid organs and solid lesions were significantly higher than their D values, indicating a high contribution of perfusion to the ADCs. CONCLUSION: Perfusion contributes to the ADCs of abdominal organs and hepatic lesions. The D and f values are useful for the characterization of hepatic lesions.

Abdomen↗
PubMed1999

Stability of Russell's viper venom toxoid (lyophilized form) on storage.

A previously developed Russell's viper venom toxoid in Myanmar is in a liquid form that shows reversion in the form of a reduced number of formaldehyde linkages and toxicity during storage at 37 degrees C and at room temperature. In order to have a safe, potent and stable toxoid, a lyophilized form was prepared in the present study from the liquid toxoid through the use of a freeze dryer. Both the liquid and lyophilized forms were then stored at 4 degrees C and at room temperature, and in addition to safety and immunogenicity tests, biochemical parameters such as the protein content, the activity of venom enzymes (proteinase, phospholipase A, phosphodiesterase, and arginine esterase), and the released free formalin amounts were assessed at 3-month intervals over a period of 1 year. The results indicate that under both conditions, the lyophilized toxoid shows minimum changes in enzyme activity, a reduced tendency toward formaldehyde linkage, no toxicity, and more immunogenicity in comparison with the respective liquid toxoids. It could therefore be hypothesized that Russell's viper venom toxoid in a lyophilized form is more promising in terms of efficacy and stability for prophylactic use in human immunization than the conventional toxoid in a liquid form.

Animals↗
PubMed1995

Gastrointestinal haemorrhage from a jejunal gangliocytic paraganglioma.

A case of jejunal gangliocytic paraganglioma is reported in a 54 year old woman who presented with brisk melaena. The tumour was not encapsulated, involved the mucosa and submucosa, and was composed of epithelial nests, spindle cells, and ganglion cells. These cells were mixed, giving carcinoid-like, paraganglioma-like, and ganglioneuroma-like patterns in different areas of the tumour. The lesion was excised locally and recovery was uneventful. Only four previous cases have been reported at this site.

Female↗
PubMed1994

Analysis of relative proliferation rates of Wilms' tumor components using proliferating cell nuclear antigen and MIB-1 (Ki-67 equivalent antigen) immunostaining and assessment of mitotic index.

BACKGROUND: Flow-cytometric analysis of proliferation index (PI) has potential use in predicting prognosis in malignancy. Its relevance to heterogeneous tumors has not been conclusively studied. In nephroblastoma, where the epithelial components are considered more differentiated than others, potentially different PIs may exist within a single lesion based on the inverse relation between differentiation and proliferation. Proliferating cell nuclear antigen (PCNA) and MIB-1 (Ki-67 equivalent antigen) demonstration in histologic sections by immunoperoxidase methods may allow for determination of PI in relation to tissue type. EXPERIMENTAL DESIGN: A consecutive unselected series of 8 pediatric nephroblastoma patients was used to study the relation between PI and histologic differentiation as established by flow-cytometric analysis of nuclear suspensions prepared from formalin-fixed and paraffin-embedded tissue and by PCNA/MIB1 staining of parallel histologic sections. PI by PCNA/MIB1 was established using 5-microns paraffin sections, immunoperoxidase, and quantification procedures detailed in the literature. The mitotic index (MI) of tissue components was separately assessed using 5-microns hematoxylin and eosin-stained sections and counting procedures detailed in the literature. RESULTS: The 8 lesions showed a PI of 4 to 20% as determined by flow cytometry. Using PCNA staining, the epithelium showed a mean PI of 55.5% (range 40 to 80%), that was significantly higher (p < 0.001, Wilcoxon's two-tailed rank sum test) than blastema (mean PI: 34.1%, range 17.5 to 76.5%) and stroma (mean PI of 14.9%, range 5 to 24%, p < 0.001, Wilcoxon's two-tailed rank sum test). Although, probably due to tissue antigen preservation, acceptable MIB-1 staining was not achieved in all lesions (5 of 8), the results, although generally with lower labeling indices, confirmed the PCNA findings. The relative MI of epithelial components was higher than that of stroma and blastema in keeping with the immunocytochemical findings. In 6 of 8 cases, the PI by flow-cytometric analysis was lower than the lowest value for the PI (labeling index) of an individual tissue type found by PCNA or MIB staining. CONCLUSIONS: The differences found between PI of the different tissue components in nephroblastoma are difficult to understand if the epithelial components (with the highest PI values) are considered as differentiation products from the other components of the lesion. The relation between PIs as determined by PCNA/MIB-1 analysis/mitotic index, for the three components and the PI as established by flow cytometry is not simply explained by the relative volume of the tissue components.

Cell Division↗
PubMedDate not supplied

Diffuse large cell lymphoma of B-cell type associated with reactive hemophagocytosis.

Some lymphomas, virtually all phenotypically of the T-cell type, have been associated with the phenomenon of hemophagocytosis. Only two B-cell lymphomas, one T-cell-rich and the other an angiocentric lymphoma, have been observed to exhibit this phenomenon. A case is reported of a diffuse large cell lymphoma of the B-cell type associated with reactive hemophagocytosis. Cytokines or other humoral factors produced by the lymphoma are a possible cause, and their effect is probably systemic. There is some evidence suggesting correlation of hemophagocytosis with tumor aggressiveness.

Adult↗