Biomedical subjects

M Y Soo

Publications and source records attributed to M Y Soo.

14 recordsLinked to original sources

PubMed2001

Antibody response to Epstein-Barr virus Rta protein in patients with nasopharyngeal carcinoma: a new serologic parameter for diagnosis.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is associated closely with Epstein-Barr virus (EBV). The authors previously reported that an EBV immediate-early gene, BRLF1, was expressed frequently in NPC tumors, and a significant elevation in immunoglobulin G (IgG) antibodies directed against BRLF1 gene product Rta was detected in NPC sera by a radioactive immunoprecipitation assay. To simplify and to make the detection more quantitative, an enzyme-linked immnunosorbent assay (ELISA) was developed in this study. METHODS: Antigen domains of Rta were identified further using an immunoprecipitation assay. Two glutathione-S-transferase (GST) recombinant Rta fragments (R150-GST and R185-GST) were prepared subsequently and were used as antigens in the ELISA. Serum samples derived from 51 patients with NPC patients, 115 non-NPC ENT patients, and 47 healthy volunteers were examined for the presence of antibodies directed against Rta. RESULTS: Among the patients with NPC, 74.5% showed a positive IgG response to R150-GST, and 62.7% showed a positive IgG response to R185-GST, with 80.4% positive for either fragment. In contrast, the reactions were positive in only 8.5% of healthy volunteers and 13.0% of control patients. When using a mixture of the two recombinant Rta proteins as coating antigens, the IgG positive responses were 82.3%, 10.6%, and 14.8%, respectively, in patients with NPC, healthy volunteers, and control patients. It is noteworthy that 51.0% of the NPC sera showed a positive immunoglobulin A (IgA) response, with none of the control patients showing obvious reactivity. Both the IgG response and the IgA response to Rta protein in patients with NPC were correlated with the IgA response to EBV early antigens and virus capsid antigens, the classic serologic markers used to diagnose NPC. CONCLUSIONS: The ELISA method described for the detection of IgG antibodies directed against recombinant Rta proteins is simple and reliable and may be useful as a serologic parameter for the screening and diagnosis of patients with NPC.

Antibodies, Viral↗

PubMed2001

Haemangiopericytoma of the trigeminal nerve.

A 41-year-old man presented with a 4-year history of progressive right-sided diplopia on lateral gaze and right nasolabial paraesthesia. A CT revealed minor bone erosion of Meckel's cave and of the right petrous apex by a uniformly enhancing lesion at the base of the skull. Magnetic resonance imaging on three occasions over 2 years showed tumour, measuring 4 cm in diameter, with features suggestive of a trigeminal neuroma. At surgery the lesion had the macroscopic appearance of a giant schwannoma. Histopathological findings were that of a meningeal haemangiopericytoma (HPC) of the trigeminal nerve. Intracranial HPC are rare and aggressive tumours of the central nervous system. They usually arise from the falx, tentorium and dural sinuses. The present case is unique as it originates from a cranial nerve.

Adult↗

PubMed2001

Chordoma: review of clinicoradiological features and factors affecting survival.

This study reviews the clinicoradiological features of cranial and sacrospinal chordomas and identifies factors affecting survival. Nineteen patients seen between January 1980 and December 2000 with histopathological diagnosis of chordomas were retrospectively reviewed with reference to clinical presentation, imaging features, treatment modalities and post-therapy status. Eight had tumours in the skull base while 11 patients had spinal and sacrococcygeal lesions. Surgical resection was performed in 16 patients whose subsequent natural history was used to identify clinical indicators that may influence survival. Completeness of resection, age, gender and postoperative irradiation were subjected to analysis using the Cox proportional hazard models. Kaplan-Meir survival curves illustrate the survival distributions. Diplopia and facial pain are prime clinical presentations in cranial lesions, while extremity weakness and a sacrogluteal mass are common complaints in the sacrospinal group. Lesional calcifications are present in 40% while an osteolytic soft tissue mass is detectable by CT in all cases. Heterogeneous signals and internal septations on T2-weighted MRI are predominant features. In sacrospinal tumours, complete excision with adjuvant radiotherapy achieves the best results with a disease-free survival of more than 5 years. The clinical and imaging findings in this study are in accordance with those of other series. Except for complete surgical excision followed by radiotherapy in the subset of patients with sacrospinal tumours, none of the other clinical indicators show a statistical significant influence on survival.

Adolescent↗

PubMed2001

Clinics in Diagnostic imaging. Sacrococccygeal chordoma.

A 41-year-old man with a sacrococcygeal chordoma is presented with emphasis on its morphological and imaging features. Examples of chordomas at other sites situated along the skull base and spinal axis are illustrated. Bone erosion and expanding soft tissue mass are invariably present on both enhanced computed tomography and magnetic resonance imaging. Sacrococcygeal chordomas are usually large on initial presentation and treatment is targeted at complete surgical excision since incomplete resection invariably leads to recurrence and distant metastases. Skull base chordomas are smaller but are less accessible to complete removal. Adjuvant radiotherapy is offered under these circumstances with the view to delay recurrence. The biological behaviour and prognostic factors for survival are summarised.

Adult↗

PubMed2000

Symptomatic ossification of the posterior longitudinal ligament of the cervical spine: pictorial essay.

Symptomatic ossification of the posterior longitudinal ligament (OPLL) of the cervical spine is a rare but well-documented condition. It is the causative factor in up to 5% of cases presenting with cervical radiculopathy or myelopathy. Computed tomography is the modality of choice in showing the distinctive characteristics and extent of the disease. Magnetic resonance imaging (MRI) is sensitive in detecting cord compression and its attendant complications. Cervical OPLL commonly affects those of middle and advanced age, and the condition is noted to be particularly common in Japanese, although other racial groups are also affected. A 'mushroom' or 'hill' shape on axial CT typifies OPLL. A sharp radiolucent line separating the posterior vertebral margin from the superficial component of the ossified ligament is a characteristic feature.

Cervical Vertebrae↗

PubMed2000

Clinics in diagnostic imaging (49). Cerebello-tonsillar haemangioblastoma.

A 39-year-old man with cerebello-tonsillar haemangioblastoma is presented,with emphasis on its morphological and imaging features. Although both computed tomography and cerebral angiography are very useful imaging modalities in helping to establish a radiological diagnosis, magnetic resonance (MR) imaging is more accurate and sensitive in depicting the lesion nature and extent. MR imaging is especially reliable in detecting multiple and other associated lesions within the central nervous system, such that a conclusive diagnosis of the von Hippel-Lindau syndrome can be made in selected cases. It is important to identify isolated haemangioblastomas as they constitute a relatively high percentage of benign resectable tumours within the posterior fossa.The differential diagnosis and imaging features of other posterior fossa tumours are also discussed.

Adult↗

PubMed2000

Clinics in diagnostic imaging (55). Ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament (OPLL) of the cervical spine associated with diffuse idiopathic skeletal hyperostosis is described in a 70-year-old Caucasian man presenting with a rapidly progressive myelopathy. The acute nature of his myelopathic symptoms and cervical canal stenosis necessitated posterior decompressive surgery. Four other patients with OPLL are presented to illustrate the spectrum of imaging findings. The computed tomographic features of OPLL are distinctive.A 2-5 mm thick linear ossified strip along the posterior vertebral margin usually at mid cervical (C3 to C5) level characterises the condition. Magnetic resonance (MR) imaging is valuable in excluding possible cord damage and associated disc lesions prior to surgery. A calcified central sequestrated disc is the only condition that may be mistaken for the segmental and retrodiscal forms of OPLL In a clinical setting of compressive myelopathy, it is pertinent to distinguish between these two conditions since a sequestrated disc has a more favourable surgical prognosis. The merits and relevance of anterior and posterior surgery together with their possible complications are outlined.

Aged↗

PubMed1999

Elevated blood levels of soluble tumor necrosis factor receptors in nasopharyngeal carcinoma: correlation with humoral immune response to lytic replication of Epstein-Barr virus.

Nasopharyngeal carcinoma (NPC) is tightly associated with Epstein-Barr virus (EBV) infection and a heavy infiltration of lymphoid cells in the tumor tissue. Although various lines of evidence have shown that the immune systems of NPC patients have the potential to attack the tumor cells, it is not yet understood how this potential is blocked. In this study we determined the circulatory soluble tumor necrosis factor receptors (sTNFRI and sTNFRII), which are proven to be inhibitory to the anti-tumor effects of tumor necrosis factor-alpha (TNF-alpha), in NPC patients. The serum concentration of both sTNFRI and sTNFRII was determined with an ELISA method, and shown to be significantly higher in 28 NPC patients than in matched healthy controls. This elevation was found to be positively correlated with the serum titers of IgA against EBV early antigens and viral capsid antigens in NPC patients, suggesting that the increased serum concentration of sTNFRI and sTNFRII is possibly due to the EBV infection in NPC tumor cells. This is partly supported by FACS analysis of the circulatory T cells. Phenotypical expression of activation markers such as CD25, CD38, CD69 and CD71 in blood T cells was not significantly different between the NPC and control individuals, indicating the elevation of the sTNFRs is indeed derived from the local immune response in the tumor area. Based on these results, it seems that the increased sTNFRs may act as an inhibitor to decrease the host immune response towards tumor cells in NPC patients.

Adult↗

PubMed1998

Spiral CT scanning in the detection and evaluation of aneurysms of the Circle of Willis.

PURPOSE: To assess the utility of spiral computed tomography (CT) with three-dimensional reconstruction in defining aneurysms of the Circle of Willis. METHODS: Eighty-one patients with angiographic or surgical correlation were studied between 1993 and 1995, with surface rendered reconstructions of the arteries of the Circle of Willis. RESULTS: Spiral CT was useful in six clinical situations: further assessment in cases with CT suspicion of an aneurysm, follow-up of known untreated aneurysms or aneurysm remnants, subarachnoid hemorrhage (SAH) with negative angiography, a past or family history of aneurysms, and improved definition of aneurysm anatomy. Ten of fifteen patients with previous surgery had no significant artifacts on the spiral study. In 66 other patients studied in search of aneurysms, the sensitivity of detection was 95% and specificity 74%. Seventeen of nineteen aneurysms 3 mm or less in size and 38 of 39 larger were detected by spiral CT. Four of thirteen patients with SAH and previous negative angiography had aneurysms identified, which were confirmed at surgery. CONCLUSIONS: There is great promise in the use of spiral CT in demonstrating aneurysms of the Circle of Willis, including very small ones. Careful detailing of scan protocols and meticulous examination of multiplanar images are needed for maximum accuracy.

Adolescent↗

PubMed1998

Epstein Barr virus (EBV) antibodies in the diagnosis of NPC--comparison between IFA and two commercial ELISA kits.

BACKGROUND: Antibodies to Epstein Barr Virus (EBV) antigens have been used for the diagnosis of nasopharyngeal carcinoma (NPC). While immunofluorescence assays (IFA) of IgA antiviral capsid and early antigens have been the mainstay of this diagnosis, enzyme immunoassays (ELISA) of various EBV antigens are now available. However in almost all of these assays, the sensitivities and specificities have been calculated using blood donors and normal hospital staff as controls, who may not be the most appropriate controls. We wanted to evaluate the usefulness of IFA and ELISA of various EBV antigens in a clinical setting to distinguish between patients with NPC and those suspected of NPC but being biopsy negative. METHODS: Between January 1987 and June 1988, 322 consecutive patients suspected of NPC and who had a post-nasal biopsy were studied. Blood was taken for EBV tests before diagnosis. Tests included IFA and ELISA IgA anti-VCA and anti-EA and ELISA IgA and IgG anti-ribonucleotide reductase, a cloned EA antigen. RESULTS: IFA IgA anti-VCA together with IFA IgA anti-EA both at a cut-off of 1:10 gave the best discrimination between patients with NPC and those suspected of NPC but were biopsy negative. CONCLUSION: The ELISA IgG anti-ribonucleotide reductase test is convenient to perform and looks very promising. An ELISA using a cocktail of cloned EA peptides may be even better.

Antibodies, Viral↗

PubMed1997

Cervical spine degenerative diseases: an evaluation of clinical and imaging features in surgical decisions.

In clinically severe cervical spondylosis, imaging plays a vital role in surgical decisions. A prime factor is acquired canal stenosis with cord compression. To validate this concept, the clinical and imaging features of 20 patients with spondylotic myelopathy and 24 with radiculopathy were retrospectively reviewed. All had computed tomographic myelography (CTM) as part of their clinical work-up. The patients' clinical severity was graded as mild, moderate and severe; the age, length of illness and a history of eventual surgery or otherwise were recorded. At the level of maximum compression the following parameters were obtained from the axial CTM images: surface area and ratio of the anteroposterior to the transverse diameter of the cord; subarachnoid space and vertebral canal areas. Data were statistically analysed. A significant association exists between surgery and increasing severity of symptoms (P = 0.04), and advancing age (P = 0.01). These associations hold true for myelopathy and radiculopathy. A strong association is present between surgery and the surface area of the cord (P = 0.01), being applicable to myelopathy only. The other parameters show no association with surgical decisions. It is concluded that with myelopathy a narrow cord area at the level of maximum compression, and moderate--severe functional impairment are indicators for surgical intervention.

Case-Control Studies↗

PubMed1996

Imaging findings in rabies.

A 10 year old Vietnamese girl presented with clinical features of an acute encephalitic process. A cerebral angiogram performed to rule out vasculitis showed narrowing at the supraclinoid internal carotid and terminal basilar arteries. A diagnosis of rabies was established at autopsy. Although the major blood vessels and basal meninges were normal it was possible that transient arterial spasm induced by the viral infection was responsible for the angiographic appearance. Other imaging findings in our patient are described with a brief review of the literature. This is only the second case of rabies reported in Australia. Rabies is a rare disease in the Australian community. Recently one patient with atypical clinical presentation was confirmed to have the disease only at autopsy. In the clinical work-up, various radiological examinations were performed and a range of interesting features were encountered including an abnormal cerebral angiogram. The purpose of this paper is to report on these unusual features and to review those documented in the literature.

Carotid Artery, Internal↗

PubMed1994

Transient global amnesia following cerebral angiography with non-ionic contrast medium.

Transient global amnesia (TGA) is an uncommon syndrome of recent memory deficit and inability to learn new data, usually resolving within 24 h. Two cases following use of non-ionic contrast media in cerebral angiography are described. The neuroanatomy of memory is reviewed. Possible aetiologies of TGA in relation to cerebral angiography include ischaemia (embolic, arterial spasm), epilepsy that may be primary or tumour-related and direct toxic effects of contrast media.

Adult↗

PubMed1993

Clival chordomas.

Three cases of clival chordomas are reviewed and the findings are compared to those in the recent literature. In the first case the tumour arose from the basion, spreading downwards to invade the upper cervical canal and the paravertebral fascial planes. The second case is a rare case since it affects a 12 year old pre-adolescent boy. The third case showed the characteristic features of petro-clival erosion and a large extracranial component in the nasopharynx. In all three cases, computed tomography was an excellent modality for demonstrating bone destruction, sequestra and calcification but inferior to magnetic resonance imaging (MRI) in demonstrating the soft tissue extent of the tumour. The multiplanar capability of MRI was found to be particularly useful for planning treatment. Vertebral angiography can demonstrate the tumours by vessel displacement, encasement and vascular staining. Two cases had angiography and demonstrated tumour blush. Pre-operative embolization was helpful in one case.

Adult↗