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Biomedical subjects

H F Wong

Publications and source records attributed to H F Wong.

At least 19 recordsLinked to original sources
PubMed2003

Splenic abscess caused by group A beta-haemolytic streptococcus.

UNLABELLED: A case of a pyoderma complicated with splenic abscess and bacteraemia caused by group A streptococcus was treated successfully with antibiotics alone for 4 weeks. To our knowledge, this is the first reported case of splenic abscess associated with group A streptococcal bacteraemia. Advances in antibiotic therapy and imaging techniques have improved the management and outcomes of splenic abscesses. Clinicians should be aware of the possibility of splenic abscess after a pyoderma or a sepsis-like episode. CONCLUSION: Splenic abscesses can be diagnosed by serial ultrasound or CT scan examinations and should be treated with antibiotics for 4-6 weeks.

Abscess↗
PubMed2002

Molecular genetic analysis of para-Bombay phenotypes in Chinese: a novel non-functional FUT1 allele is identified.

BACKGROUND AND OBJECTIVES: The para-Bombay phenotype (also known as H-deficient secretor) is characterized by a lack of ABH antigens on red cells, but ABH substances are found in saliva. Molecular genetic analysis was performed for five Chinese individuals serologically typed as para-Bombay. MATERIALS AND METHODS: ABO genotyping and mutational analysis of both FUT1 (or H) and FUT2 (or Se) loci were performed for these individuals using the polymerase chain reaction, single-strand conformation polymorphism analysis and direct DNA sequencing. RESULTS: The ABO genotypes of these para-Bombay individuals correlated with the types of ABH substances found in the saliva. Their FUT1 genotypes were h1h2 (three individuals), h2h2 (one individual) and h2h6 (one individual). Alleles h1 (547-552delAG) and h2 (880-882delTT) were known frameshift mutations, while h6 (522C > A) was a missense mutation (Phe174Leu) not previously reported. These three mutations were rare sequence variations, each with an allele frequency of less than 0.005. Phe174 might be functionally important because this residue is conserved from mouse to human. Their FUT2 genotypes were Se357se357,385 for the h2h6 individual and Se357Se357) for the others. Both FUT2 alleles were known: one functional (Se357) and one weakly functional (se357,385). That they carried at least one copy of a functional FUT2 allele was consistent with their secretor status. As FUT1 and FUT2 are adjacent on 19q13.3, there are three possible haplotypes in these para-Bombay individuals: h1-Se357; h2-Se357; and h6-se357,385. CONCLUSIONS: A novel non-functional FUT1 allele (522C > A, or Phe174Leu) was identified in a para-Bombay individual and on a se357,385 haplotype background.

ABO Blood-Group System↗
PubMed2001

Air enema for diagnosis and reduction of intussusception in children: clinical experience and fluoroscopy time correlation.

PURPOSE: The objective of this study was to correlate the fluoroscopy time with radiologic outcome in the pneumoreduction of intussusception in children. METHODS: From September 1995 to December 1997, a prospective analysis of 181 cases of pediatric intussusception with pneumoreduction without sedation was done. A receiver operating characteristic curve of fluoroscopy time was drawn for correlation with radiologic outcome. RESULTS: The overall success and failure rates of pneumoreduction were 84% and 16%, respectively. Three patients (1.6%) experienced colon perforation. The mean fluoroscopy time was 2.8 +/- 1.7 minutes in successful procedure and 4.9 +/- 2.8 minutes in failed procedures (P < 0.001). Analysis of the receiver operating characteristic curve of fluoroscopy time indicates that 4 minutes fluoroscopy time was a good critical point in differentiating successful and failed cases. In those 18 patients who had successful reduction with fluoroscopy times of more than 4 minutes, 4 patients had clinical symptoms for more than 1 day and 14 patients less than 1 day. One of those 4 patients required operation 1 day later because of peritonitis caused by necrosis of terminal ileum. Two patients had high fever in the next 2 days and recovered after antibiotic treatment. CONCLUSIONS: Pneumoreduction is a good method in treatment of intussusception with high successful rate. Four minutes is the critical point of procedure. Reduction with greater than 4 minutes in those patients having illness more than 1 day might not benefit and have more complications.

Air↗
PubMed2001

Craniofacial surgical simulation: application of three-dimensional medical imaging and rapid prototyping models.

BACKGROUND: Adequate assessment of the deformity, formulation of good treatment planning, and sufficient rehearsal of procedures before actually performing surgery ensure successful craniofacial surgery. Three-dimensional computed tomography (CT) imaging and facsimile models were used in combination to evaluate their function in craniofacial surgery. METHODS: Three-dimensional imaging and facsimile models were used for reconstruction of craniofacial deformity. CT data were acquired, processed, and reconstructed to display 3-dimensional images. The images were used for evaluation of the deformity. The images were then manipulated to create multiple osseous objects. Surgical simulation was performed by moving the computer images. The image processing and manipulation were achieved using the AnalyzePC program. The raw CT data were transformed into a readable format and transferred to produce facsimile models using rapid prototyping technology. The skull models were used for evaluation and surgical simulation. Both methods were compared and used to assist in surgery, which was performed according to the simulations. RESULTS: Three-dimensional CT imaging and facsimile models were helpful for simulation of craniofacial surgery. The actual surgery results were satisfactory without complications. Particular advantages were the unlimited trials with the imaging method, and the feeling of reality with the model method. CONCLUSIONS: Craniofacial surgery is facilitated by preoperative simulation of procedures. Both 3-dimensional CT imaging and facsimile models are helpful for craniofacial surgical simulation.

Craniofacial Abnormalities↗
PubMed2000

Antral web--a rare cause of vomiting in children.

Antral web is a rare cause of gastric-outlet obstruction. We report a case of gastric antral web with intermittent vomiting in a 10-year-old girl who received medical treatment for 6 months. The literature on this anomaly is reviewed with respect to differential diagnosis on the basis of upper gastrointestinal radiographic series, gastroscopy, and treatment planning.

Abdominal Pain↗
PubMed2000

Embolization of a pulmonary arteriovenous fistula by electrolytic detachable coils: case report.

Transarterial embolization with detachable coils is a technique commonly used for the treatment of intracranial aneurysms. We report on a patient with a pulmonary arteriovenous fistula (PAVF) treated successfully with this technique. The patient presented with a history of intermittent hemoptysis, nasal bleeding, numbness of the upper extremities, and seizures. Computed tomographic angiography and magnetic resonance angiography demonstrated a single-hole arteriovenous fistular lesion in the left lower lung. Pre-embolization superselective pulmonary angiography revealed multiple fistulae communicating to the venous sac of the lesion. Eleven detachable coils were deployed into the venous sac, with resultant total occlusion of the pulmonary arteriovenous fistula. We conclude that venous sac embolization in treating this kind of patients is effective. The combined use of a microcatheter system and electrolytic detachable coils may be an excellent technique for achieving this kind of embolization. Superselective angiographic evaluation is essential before embolization, because many occult feeders can be present in cases of high-flow PAVF.

Adult↗
PubMed2000

Quantitative measurement on three-dimensional computed tomography: an experimental validation using phantom objects.

BACKGROUND: The use of 3-dimensional computed tomography (CT) imaging has been applied to the craniofacial region as well as to many other parts of the human body. Quantitative measurements have frequently been performed on the 3-dimensional images. However, critical validation of the measurement has been insufficient in the literature. This study was designed to evaluate the errors of the 3-dimensional measurements. METHODS: Four phantom objects, a cube, a sphere, a cylinder, and a life-size adult skull model, were scanned using standard CT acquisition protocol. The data were transferred, reformatted, and displayed on an IBM-compatible personal computer running AnalyzePC 2.5 software. Linear, area, and volume measurements were obtained using one of the two methods. The first was physical measurement of the phantom objects using a caliper for linear measurement and mathematical calculations for area and volume measurements. The second was done by computer measurement on 3-dimensional images using the AnalyzePC 2.5 program. Each measurement was performed twice. The differences were compared between the repeated measurements and between the two methods. RESULTS: The images were displayed according to standard 3-dimensional CT protocol. The differences between the measurements were insignificant and ranged from 0.00 to 2.57%. CONCLUSION: This study validated the accuracy of the quantitative measurements on 3-dimensional CT images.

Humans↗
PubMed1999

MRI features of Balo's concentric sclerosis.

We report MRI findings in a 56-year-old woman with Balo's concentric sclerosis (BCS) who initially presented with a progressive hemiparesis. MRI showed two lesions with a concentric pattern in the left frontoparietal region and a laminated, arcuate pattern in the right frontal region. These patterns were best seen in post-contrast images and were consistent with BCS. In addition, there were several small cerebral multiple sclerosis-like plaques. The clinical symptoms improved and the MR findings regressed after corticosteroid therapy. The patient had completely recovered 12 months later, except for mild right hand numbness. MRI showed further regression of the lesions, but the concentric pattern was still present. This case demonstrated that BCS can run a benign prolonged course and may persist for a long time. Concentric or laminated contrast enhancement in the acute phase may suggest that bands of demyelination in BCS occur synchronously rather than successively.

Diffuse Cerebral Sclerosis of Schilder↗
PubMed1999

MRI of thoracic vascular lesions with emphasis on two-dimensional time-of-flight MR angiography.

MRI is a valuable method for evaluating thoracic vascular lesions by virtue of its non-invasiveness and multiplanar capability. In addition, ionizing radiation and iodinated contrast medium are not required. Electrocardiographically gated T1 weighted spin echo MRI remains the principal technique for demonstrating the anatomy and morphology of thoracic vascular diseases. Cine MRI allows dynamic evaluation of vascular flow, whereas MR angiography is particularly useful in the two-dimensional (2D) or three-dimensional (3D) display of vascular anatomy. This pictorial review illustrates the use of 2D time-of-flight MR angiography in the assessment of various thoracic vascular conditions including aortic arch and great vessel anomalies, heterotaxic syndromes, aortic dissection, aortic or arch vessel aneurysms, pulmonary embolism, pulmonary sequestration, axillofemoral bypass and tumour/vessel relationships.

Aortic Diseases↗
PubMed1998

Determination of endogenous trace metal contents in various mouse brain regions after prolonged oral administration of aluminum chloride.

Aluminum (Al) has been said to associate with the Alzheimer's-like neurodegeneration in humans. One of the proposed mechanisms for the action of Al is that excess Al might interfere with trace metal metabolism. In this study, the levels of Ca, Mg, Cu, and Zn in blood, liver, and different regions of the brain (separated into the cortex, hippocampus, cerebellum, and brainstem) were measured in mice after daily oral administration of AICI3 (100 mg/kg body weight) for 2 mo. It was found that upon prolonged oral administration of AI, serum Al level was elevated significantly. There was no marked change in serum Ca, Mg, Zn, or Cu content. In the liver, Al content was not increased but there was a significant elevation in Cu and Zn content compared to control animals, probably due to the prolonged administration of the acidic salt solution. In brain, there was a significant twofold increase in Al in the hippocampus and a significant decrease in Al in the cortex. In addition to regional changes in AI content, Zn content in the hippocampus and increased Cu content in the hippocampus, cortex, and brainstem were significantly reduced. Data demonstrated that Al could alter Zn and Cu homeostasis in selected brain regions. The possible relation between Al and neuronal cell injury was discussed.

Administration, Oral↗
PubMed1998

Preoperative embolization of meningiomas: comparison of superselective and subselective techniques.

We retrospectively compared the efficacy of preoperative superselective and subselective embolization for intracranial meningiomas. Between January and December 1996, 22 patients (7 men, 15 women, mean age 51 +/- 15.5 yr) underwent superselective embolization with 45 to 150 mm polyvinyl alcohol particles after superselective catheterization of the feeding vessels with a microcatheter system. Another 30 patients (12 men, 18 women, mean age 50 +/- 12.9 yr) underwent subselective embolization between January and December 1995 with 150 to 300 mm Gelfoam particles after catheterization of the terminal external carotid artery just proximal to the orifice of the maxillary artery with a 4- or 5-F angiocatheter. The mean intraoperative blood loss (918 versus 1450 mL, p < 0.05), amount of blood transfused (4.9 versus 7.5 units, p = 0.09), and surgical resection time (422 versus 529 min, p < 0.05) were all lower in the superselective group than in the subselective group, while the occurrence of fresh ischemic necrosis (59% versus 53%, p = 0.68), hemorrhage (77% versus 60%, p = 0.19), and embolic material (55% versus 13%, p < 0.05) on pathologic examination were higher in the superselective group. No procedure-related complications occurred in the superselective group, whereas two patients in the subselective group had postoperative scalp necrosis. Our findings show that superselective embolization is more effective than subselective embolization for preoperative endovascular devascularization of meningiomas, with significant reductions in intraoperative blood loss and surgery time. Preoperative embolization of meningiomas, if indicated, should be done with the superselective technique whenever feasible.

Adult↗
PubMed1998

Comparison of cerebral occipital gray and parietal white matter metabolite differences using PRESS and STEAM at different echo times.

BACKGROUND: Reports regarding the differences in metabolite ratios with different echo times (TEs) at various brain regions are rare. The purpose of this study is to investigate in Chinese the cerebral metabolite ratios in gray matter (GM) and white matter (WM) using both STEAM and PRESS techniques at TEs of 30 ms and 136 ms, respectively. MATERIALS AND METHODS: Using GE Signa 1.5 T Scanner with STEAM and PRESS sequences, automated single voxel localized proton magnetic resonance spectroscopy (1H-MRS) were applied to identify the metabolite ratio differences in cerebral parietal white and occipital gray matter of healthy volunteers. RESULTS: Metabolite ratios between GM and WM were significantly different in N-acetyl aspartate/creatine (Cr), choline/Cr and myo-inositol/Cr. There were also significant differences in metabolite ratios when different echo times were applied. CONCLUSION: Reliable metabolite ratios at different brain regions can be obtained using automated data acquisition and spectral processing in single voxel localized 1H-MRS. This technique may remove user-dependent bias and provide more efficient and consistent ways to analyze the spectral data. However, one must be careful in interpreting spectroscopic data based on different regions and acquisition parameters.

Adult↗
PubMed1997

CT angiography of intracranial aneurysms: advantages and pitfalls.

OBJECTIVE: To determine the clinical usefulness of computed tomography (CT) angiography in the evaluation of cerebral aneurysms. MATERIALS AND METHODS: From October 1994 through April 1996, 26 patients with 30 surgical proven intracranial aneurysms underwent both CT angiography and catheter cerebral angiography. The findings of the two methods were reviewed independently and then compared with each other. RESULTS: Comparing with catheter angiography, CT angiography was superior in demonstrating the aneurysmal neck in seven aneurysms but was inferior in one. The thrombosed part and calcification of aneurysms were clearly demonstrated on CT angiograms. CT angiography also aided in differentiating tight vascular loops from aneurysms. On CT angiograms, one posterior communicating arterial aneurysm was overlooked and another anterior choroidal artery aneurysm was misinterpreted as a posterior communicating artery aneurysm. Of note were two patients in whom the infundibulum of the orbitofrontal artery was misinterpreted as the anterior communicating artery aneurysm. CONCLUSION: CT angiography can compliment conventional catheter angiography for its better demonstration of the 3-dimensional anatomy. It can provide surgical information about the neck, calcification and thrombosed part of an aneurysm and its relation to adjacent structures. However, caution is advocated because CT angiography may fail to demonstrate small but important vessels such as posterior communicating, anterior choroidal and orbitofrontal arteries. Recognition of the limitations of CT angiography is important in minimizing interpretation errors.

Adult↗
PubMed1997

CT findings of bronchial transection.

A case of right bronchial rupture demonstrated by computed tomography (CT) is reported. Chest radiographs of a 55-year-old man who sustained blunt chest trauma showed bilateral pneumomediastinum, hydropneumothorax, and subcutaneous emphysema with fracture of the left 3rd and 4th ribs. CT showed wall defect over the right main bronchus with the air in airway contiguous to that in the mediastinum. Bronchoscopy and thoracostomy confirmed the CT findings and the patient was treated by bronchorrhaphy with end-to-end anastomosis. The airway should be meticulously evaluated in cases of mediastinal and subcutaneous emphysema, especially after trauma.

Bronchi↗
PubMed1997

Factors related to detection of blood flow by color Doppler ultrasonography in intussusception.

Color Doppler ultrasonography was performed in 125 patients with 134 intussusceptions. Color flow was present in 121 cases of intussusception (group A) and was absent in 13 cases (group B). Young age and duration of symptoms greater than 48 hr were significantly related to the nonvisualization of blood flow detected by color Doppler sonography (P < 0.05). The successful rate of air reduction was significantly higher in group A than in group B (109 of 121 versus 4 of 13). Color Doppler ultrasonography is useful to predict the reducibility of an intussuscepted intestine. The nonvisualization of blood flow by this method is not a contraindication for air reduction.

Adolescent↗