Ng Yang Hwang - Academia.edu (original) (raw)

Papers by Ng Yang Hwang

Research paper thumbnail of Laparoscopic Management of Abdominal Apoplexy

Abdominal apoplexy, otherwise known as intraperitoneal idiopathic spontaneous haemorrhage, is a r... more Abdominal apoplexy, otherwise known as intraperitoneal idiopathic spontaneous haemorrhage, is a rare condition that presents as a diagnostic dilemma and is associated with high mortality. Symptoms and signs typically are similar to other conditions presenting with upper abdominal peritonitis. Intraabdominal haemorrhage can occur from many different causes, including trauma, iatrogenic, ruptured aneurysm, gynaecological conditions, malignancy, and inflammatory or autoimmune processes. Spontaneous or idiopathic causes are much rarer. Prompt diagnosis and ligation of the bleeding vessel usually result in a good outcome. Most cases described involve males in the fifth and sixth decade of life who present in the setting of hypertension and known atherosclerotic disease and are managed with laparotomy or are diagnosed at autopsy. We present a case of abdominal apoplexy managed laparoscopically in a healthy 20-year-old male with no pre-existing medical conditions. This case highlights the ...

Research paper thumbnail of Assessment of Arsenic Exposure by Measurement of Urinary Speciated Inorganic Arsenic Metabolites in Workers in a Semiconductor Manufacturing Plant

Annals of Occupational and Environmental Medicine, 2013

Objectives: The purpose of this study was to evaluate the exposure to arsenic in preventive maint... more Objectives: The purpose of this study was to evaluate the exposure to arsenic in preventive maintenance (PM) engineers in a semiconductor industry by detecting speciated inorganic arsenic metabolites in the urine. Methods: The exposed group included 8 PM engineers from the clean process area and 13 PM engineers from the ion implantation process area; the non-exposed group consisted of 14 office workers from another company who were not occupationally exposed to arsenic. A spot urine specimen was collected from each participant for the detection and measurement of speciated inorganic arsenic metabolites. Metabolites were separated by high performance liquid chromatography-inductively coupled plasma spectrometry-mass spectrometry. Results: Urinary arsenic metabolite concentrations were 1.73 g/L, 0.76 g/L, 3.45 g/L, 43.65 g/L, and 51.32 g/L for trivalent arsenic (As 3+), pentavalent arsenic (As 5+), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and total inorganic arsenic metabolites (As 3+ + As 5+ + MMA + DMA), respectively, in clean process PM engineers. In ion implantation process PM engineers, the concentrations were 1.74 g/L, 0.39 g/L, 3.08 g/L, 23.17 g/L, 28.92 g/L for As 3+ , As 5+ , MMA, DMA, and total inorganic arsenic metabolites, respectively. Levels of urinary As 3+ , As 5+ , MMA, and total inorganic arsenic metabolites in clean process PM engineers were significantly higher than that in the nonexposed group. Urinary As 3+ and As 5+ levels in ion implantation process PM engineers were significantly higher than that in non-exposed group. Conclusion: Levels of urinary arsenic metabolites in PM engineers from the clean process and ion implantation process areas were higher than that in office workers. For a complete assessment of arsenic exposure in the semiconductor industry, further studies are needed.

Research paper thumbnail of Expect the Unexpected: Torsion of the Gallbladder, a Rare Cause for Acute Cholecystitis

Gallbladder torsion is a rare cause for acute cholecystitis. Gallbladder torsion is unlikely to r... more Gallbladder torsion is a rare cause for acute cholecystitis. Gallbladder torsion is unlikely to respond to conservative management and requires urgent surgical intervention. We report a case of an 85-year-old female with gallbladder torsion. She presented with a clinical picture consistent with acute cholecystitis. Radiological findings showed signs that elude to the diagnosis and intra-operative findings showed a complete torsion with a free-floating gallbladder. This case highlights the need to have a high index of suspicion for gallbladder torsion as a differential diagnosis for right upper quadrant (RUQ) pain apart from the typical calculous acute cholecystitis, especially in high risk groups such as thin, elderly females. Prompt decision for cholecystectomy is necessary and is likely to result in a good outcome.

Research paper thumbnail of Apparatus for Early Detection of Paralysis Based on Motion Sensing

Research paper thumbnail of Multifocal Inflammatory Leukoencephalopathy Associated with Levamisole and 5-Fluorouracil: Case Report

Neurosurgery

Levamisole and 5-fluorouracil have now become the standard chemotherapeutic regimen for patients ... more Levamisole and 5-fluorouracil have now become the standard chemotherapeutic regimen for patients with Stage III colon carcinoma. A case of multifocal inflammatory leukoencephalopathy secondary to levamisole alone or combination of levamisole and 5-fluorouracil is reported. Magnetic resonance imaging with gadolinium demonstrated multifocal contrast-enhancing frontal, parietal, occipital, and periventricular white matter lesions. A stereotactic biopsy revealed reactive gliosis and macrophage infiltration, without evidence of metastatic tumor. Despite continuation of 5-fluorouracil, resolution of contrast-enhancing lesions on magnetic resonance imaging without further neurological sequelae occurred when levamisole was stopped. The patient died with evidence of systemic metastasis 6 months later. Autopsy examination of the brain revealed multifocal demyelinating lesions, with no evidence of metastatic tumor. Immunoperoxidase studies of demyelinated lesions demonstrated infiltrating macrophages strongly positive for Class II antigens, interleukin-6, and interleukin-1 alpha. Surrounding astrocytes were positive for granulocyte macrophage colony-stimulating factor. Small numbers of perivascular T cells were present. This patient represents the first autopsy documented case of levamisole associated multifocal inflammatory leukoencephalopathy.

Research paper thumbnail of A Case of Medulloblastoma Associated with Rubinstein-Taybi Syndrome

=Abstract=A case of medulloblastoma associated with Rubinstein-Taybi syndrome is reported, a s th... more =Abstract=A case of medulloblastoma associated with Rubinstein-Taybi syndrome is reported, a s this is the first reported case of medulloblastoma associated with this syndrome, to our knowlegde. The patient was an 8 112-year-old girl who had a typical facial appearance, broadening of the thumbs and great toes, and mental retardation. She had been exhibiting irritability for one month. A brain CT scan showed a homogeneously enhanced round mass in the midline of the posterior fossa with marked hydrocephalus. Gross total removal of the mass was performed, and the pathology showed findings of medulloblastoma.

Research paper thumbnail of Laparoscopic Management of Abdominal Apoplexy

Abdominal apoplexy, otherwise known as intraperitoneal idiopathic spontaneous haemorrhage, is a r... more Abdominal apoplexy, otherwise known as intraperitoneal idiopathic spontaneous haemorrhage, is a rare condition that presents as a diagnostic dilemma and is associated with high mortality. Symptoms and signs typically are similar to other conditions presenting with upper abdominal peritonitis. Intraabdominal haemorrhage can occur from many different causes, including trauma, iatrogenic, ruptured aneurysm, gynaecological conditions, malignancy, and inflammatory or autoimmune processes. Spontaneous or idiopathic causes are much rarer. Prompt diagnosis and ligation of the bleeding vessel usually result in a good outcome. Most cases described involve males in the fifth and sixth decade of life who present in the setting of hypertension and known atherosclerotic disease and are managed with laparotomy or are diagnosed at autopsy. We present a case of abdominal apoplexy managed laparoscopically in a healthy 20-year-old male with no pre-existing medical conditions. This case highlights the ...

Research paper thumbnail of Assessment of Arsenic Exposure by Measurement of Urinary Speciated Inorganic Arsenic Metabolites in Workers in a Semiconductor Manufacturing Plant

Annals of Occupational and Environmental Medicine, 2013

Objectives: The purpose of this study was to evaluate the exposure to arsenic in preventive maint... more Objectives: The purpose of this study was to evaluate the exposure to arsenic in preventive maintenance (PM) engineers in a semiconductor industry by detecting speciated inorganic arsenic metabolites in the urine. Methods: The exposed group included 8 PM engineers from the clean process area and 13 PM engineers from the ion implantation process area; the non-exposed group consisted of 14 office workers from another company who were not occupationally exposed to arsenic. A spot urine specimen was collected from each participant for the detection and measurement of speciated inorganic arsenic metabolites. Metabolites were separated by high performance liquid chromatography-inductively coupled plasma spectrometry-mass spectrometry. Results: Urinary arsenic metabolite concentrations were 1.73 g/L, 0.76 g/L, 3.45 g/L, 43.65 g/L, and 51.32 g/L for trivalent arsenic (As 3+), pentavalent arsenic (As 5+), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and total inorganic arsenic metabolites (As 3+ + As 5+ + MMA + DMA), respectively, in clean process PM engineers. In ion implantation process PM engineers, the concentrations were 1.74 g/L, 0.39 g/L, 3.08 g/L, 23.17 g/L, 28.92 g/L for As 3+ , As 5+ , MMA, DMA, and total inorganic arsenic metabolites, respectively. Levels of urinary As 3+ , As 5+ , MMA, and total inorganic arsenic metabolites in clean process PM engineers were significantly higher than that in the nonexposed group. Urinary As 3+ and As 5+ levels in ion implantation process PM engineers were significantly higher than that in non-exposed group. Conclusion: Levels of urinary arsenic metabolites in PM engineers from the clean process and ion implantation process areas were higher than that in office workers. For a complete assessment of arsenic exposure in the semiconductor industry, further studies are needed.

Research paper thumbnail of Expect the Unexpected: Torsion of the Gallbladder, a Rare Cause for Acute Cholecystitis

Gallbladder torsion is a rare cause for acute cholecystitis. Gallbladder torsion is unlikely to r... more Gallbladder torsion is a rare cause for acute cholecystitis. Gallbladder torsion is unlikely to respond to conservative management and requires urgent surgical intervention. We report a case of an 85-year-old female with gallbladder torsion. She presented with a clinical picture consistent with acute cholecystitis. Radiological findings showed signs that elude to the diagnosis and intra-operative findings showed a complete torsion with a free-floating gallbladder. This case highlights the need to have a high index of suspicion for gallbladder torsion as a differential diagnosis for right upper quadrant (RUQ) pain apart from the typical calculous acute cholecystitis, especially in high risk groups such as thin, elderly females. Prompt decision for cholecystectomy is necessary and is likely to result in a good outcome.

Research paper thumbnail of Apparatus for Early Detection of Paralysis Based on Motion Sensing

Research paper thumbnail of Multifocal Inflammatory Leukoencephalopathy Associated with Levamisole and 5-Fluorouracil: Case Report

Neurosurgery

Levamisole and 5-fluorouracil have now become the standard chemotherapeutic regimen for patients ... more Levamisole and 5-fluorouracil have now become the standard chemotherapeutic regimen for patients with Stage III colon carcinoma. A case of multifocal inflammatory leukoencephalopathy secondary to levamisole alone or combination of levamisole and 5-fluorouracil is reported. Magnetic resonance imaging with gadolinium demonstrated multifocal contrast-enhancing frontal, parietal, occipital, and periventricular white matter lesions. A stereotactic biopsy revealed reactive gliosis and macrophage infiltration, without evidence of metastatic tumor. Despite continuation of 5-fluorouracil, resolution of contrast-enhancing lesions on magnetic resonance imaging without further neurological sequelae occurred when levamisole was stopped. The patient died with evidence of systemic metastasis 6 months later. Autopsy examination of the brain revealed multifocal demyelinating lesions, with no evidence of metastatic tumor. Immunoperoxidase studies of demyelinated lesions demonstrated infiltrating macrophages strongly positive for Class II antigens, interleukin-6, and interleukin-1 alpha. Surrounding astrocytes were positive for granulocyte macrophage colony-stimulating factor. Small numbers of perivascular T cells were present. This patient represents the first autopsy documented case of levamisole associated multifocal inflammatory leukoencephalopathy.

Research paper thumbnail of A Case of Medulloblastoma Associated with Rubinstein-Taybi Syndrome

=Abstract=A case of medulloblastoma associated with Rubinstein-Taybi syndrome is reported, a s th... more =Abstract=A case of medulloblastoma associated with Rubinstein-Taybi syndrome is reported, a s this is the first reported case of medulloblastoma associated with this syndrome, to our knowlegde. The patient was an 8 112-year-old girl who had a typical facial appearance, broadening of the thumbs and great toes, and mental retardation. She had been exhibiting irritability for one month. A brain CT scan showed a homogeneously enhanced round mass in the midline of the posterior fossa with marked hydrocephalus. Gross total removal of the mass was performed, and the pathology showed findings of medulloblastoma.