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Biomedical subjects

C P Wong

Publications and source records attributed to C P Wong.

At least 19 recordsLinked to original sources
PubMed2005

Study on mono-dispersed nano-size silica by surface modification for underfill applications.

In order to improve the rheological behavior of the nanosilica composite no-flow underfill, filler surface treatment using silane coupling agents was investigated to reduce the filler-filler interaction and to achieve the mono-dispersity of the nanosilica in the underfill resin. The experimental conditions of the surface treatment were investigated in a design of experiment (DOE) in terms of the pre-treatment methods, coupling agent types, concentrations, and treatment durations. The particle dispersion after treatment was evaluated by the laser particle analyzer and the transmission electron microscopy (TEM). A mono-dispersed nanosilica solution in the polar medium was achieved using optimal experimental condition. The surface chemistry of the nanosilica was studied using Fourier transformed infrared spectroscopy (FTIR). The wettability of underfill resin and water on the silane treated glass slides was studied using a goniometer. Based on the investigations, the silane-treated nanosilica fillers were incorporated into an underfill resin to formulate a nanocomposite no-flow underfill. It was found that the proper filler treatment could significantly reduce the viscosity of the nanocomposite.

Hydrolysis↗
PubMed2005

Materials science. Electronics without lead.

In conventional consumer electronics such as cell phones, lead-containing interconnects provide the conductive path between different circuit elements. Environmental concerns have led to a search for lead-free alternatives. In their Perspective, Li et al. review these efforts, which have focused on lead-free alloys and electrically conductive adhesives. Both of these approaches are showing promise, but no one lead-free interconnect material can serve as a substitute for the conventional tin-lead solder in all devices.

Journal Article↗
PubMed2003

Thyrotoxicosis: a rare presenting symptom of Hurthle cell carcinoma of the thyroid.

Hurthle cell carcinoma of the thyroid is a rare type of thyroid neoplasm. The most common clinical presentation is a single palpable thyroid nodule. The neoplasm typically presents as a nonfunctioning or cold nodule on a Tc-99m sodium pertechnetate or radioiodine thyroid scan. We report a case of Hurthle cell carcinoma of the thyroid in a woman presenting with thyrotoxicosis. The Tc-99m thyroid scan was also interesting in that the nodule was a hot or hyperfunctioning area, resulting in a rare scintigraphic finding in a rare tumor. Clinicopathologic aspects and related issues are further discussed.

Adenoma, Oxyphilic↗
PubMed2002

Subacute hepatic failure after the perinatal period with haemochromatotic siderosis at the age of 11 months: an unusual perspective on neonatal haemochromatosis.

UNLABELLED: Neonatal haemochromatosis is a rare disease characterized by the early onset of liver failure, a rapidly deteriorating clinical course and high mortality. An unusual case is presented of subacute hepatic failure in which autopsy findings at the age of 11 mo showed a haemochromatotic pattern of siderosis. Despite the similarity in the pattern of iron distribution to neonatal haemochromatosis, the clinical course was highly atypical in that the infant had later and milder presentation at 1 mo of age and slow progression into liver failure. This case illustrates the heterogeneous nature of the haemochromatotic phenotype in newborns and infants. CONCLUSION: The entity "neonatal haemochromatosis" may reflect a spectrum of diseases with diverse aetiologies. Fulminant liver disease in the newborn period can also result in similar pattern of iron distribution.

Disease Progression↗
PubMed2001

Frequent loss of heterozygosity on multiple chromosomes in Chinese esophageal squamous cell carcinomas.

Analysis of the loss of heterozygosity (LOH) detected by polymerase chain reaction techniques using 18 polymorphic markers localized to chromosomes 3p, 5, 17, and 18q in 40 Hong Kong Chinese esophageal squamous cell carcinoma (ESC) patients showed that multiple alterations on several chromosomes are involved in ESC development. The LOH rates detected for markers on chromosome 3 ranged from 44.0 to 85.7%, for chromosome 5 from 40.9 to 61.9%, for chromosome 17 from 40.0 to 100%, and for chromosome 18 from 38.9 to 58.3%. No significant association was observed between LOH and the clinical and histopathological parameters.

Aged↗
PubMed2001

Il-18 gene transfer by adenovirus prevents the development of and reverses established allergen-induced airway hyperreactivity.

We examined the role of IL-18 in preventing the development of and in reversing established allergen-induced airway inflammation and airway hyperreactivity (AHR), the cardinal features of asthma. IL-18, which potently induces IFN-gamma, was administered into the respiratory tract as cDNA in a replication-deficient adenovirus (Adv). Treatment of OVA-sensitized mice with the IL-18-expressing Adv reduced allergen-specific IL-4 production, airway eosinophilia, and mucus production, increased IFN-gamma production, and prevented the development of AHR. The effects of the IL-18 Adv treatment were dependent on the presence of IFN-gamma and IL-12. Moreover, administration of the IL-18 Adv to mice with established AHR greatly reduced AHR and IL-4 production and increased IFN-gamma production. These results demonstrate that IL-18, when administered by Adv into the respiratory tract, effectively reduces AHR and replaces an established Th2-biased immune response with a Th1-biased response.

Adenoviridae↗
PubMed2001

Incidence, aetiology, and outcome of non-traumatic coma: a population based study.

AIM: To determine the incidence, presentation, aetiology, and outcome of non-traumatic coma in children aged between 1 month and 16 years. METHODS: In this prospective, population based, epidemiological study in the former Northern NHS region of the UK, cases were notified following any hospital admission or community death associated with non-traumatic coma. Coma was defined as a Glasgow Coma Score below 12 for more than six hours. RESULTS: The incidence of non-traumatic coma was 30.8 per 100 000 children under 16 per year (6.0 per 100 000 general population per year). The age specific incidence was notably higher in the first year of life (160 per 100 000 children per year). CNS specific presentations became commoner with increasing age. In infants, nearly two thirds of presentations were with non-specific, systemic signs. Infection was the commonest overall aetiology. Aetiology remained unknown in 14% despite extensive investigation and/or autopsy. Mortality was highly dependent on aetiology, with aetiology specific mortality rates varying from 3% to 84%. With follow up to approximately 12 months, overall series mortality was 46%.

Adolescent↗
PubMed2001

Cognitive and adaptive outcomes and age at insult effects after non-traumatic coma.

Cognitive and adaptive behavioural outcome were studied in the identified survivors of a population based study of non-traumatic coma (NTC) in childhood. Children were assessed early (six weeks) and late (12 months) after NTC. At least 7% of those children in whom no suspicions of prior neurodevelopmental morbidity existed showed moderate or severe disability following NTC. Children over 2 years of age at insult showed some improvement between early and late assessments; however, children below 2 years showed no improvement. Differing age at insult effects were observed between aetiological groups. A relation between early age at first insult and poor outcome was particularly evident among children experiencing NTC caused by epilepsy.

Adaptation, Psychological↗
PubMed2000

Recombinant adenovirus vaccine encoding a chimeric T-cell antigen receptor induces protective immunity against a T-cell lymphoma.

Vaccination using recombinant tumor-derived T-cell antigen receptor (TCR) protein induces a protective, idiotype-specific immune response against a murine T-cell tumor. However, the technically demanding task of producing patient-specific, recombinant TCR protein restricts the translation of TCR vaccines for clinical use. We report here the development of an effective recombinant TCR adenovirus vaccine. Individual adenoviruses were constructed to encode a chimeric TCR derived from either tumor Valpha or Vbeta regions fused to xenogeneic human constant regions. Coinjection of the chimeric alpha- and the beta-TCR adenoviruses protected mice against tumors. The level of protection was comparable to that achieved by an optimized regimen of recombinant TCR protein vaccines. Tumor immunity induced by TCR adenoviruses required the xenogeneic constant regions and was mediated by CD8+ T cells. Independent vaccines consisting of adenovirus expressing either chimeric alpha- or beta-TCR chain also stimulated a protective immune response. Immunization with TCR adenovirus may offer a new efficacious, protein-free vaccination approach for the treatment of T-cell malignancies.

Animals↗
PubMed1999

TCR vaccines against T cell lymphoma: QS-21 and IL-12 adjuvants induce a protective CD8+ T cell response.

Tumor-specific TCR can serve as an effective target for active immunotherapy of T cell malignancies. Using the murine T cell tumor model C6VL, vaccination with C6VL TCR protected mice from a subsequent lethal dose of tumor cells. This study characterizes the immune mechanisms involved in the tumor protection, and the influence of immunologic adjuvants in inducing a protective immune response. Immune responses induced by TCR vaccines formulated with various adjuvants: QS-21, IL-12, SAF-1, CD40L, and GM-CSF were compared. QS-21, IL-12, and SAF-1 biased the humoral immune response toward Th1-type, reflected by the induction of IgG2a and IgG2b anti-C6VL TCR Abs. CD40L and GM-CSF exclusively produced IgG1 Abs, reflecting a Th2-type immune response. In our tumor model system, only vaccines containing adjuvants that induced a Th1-type immune response favored tumor protection. Furthermore, we demonstrated that CD8+ T cells were necessary and sufficient for tumor protection using anti-CD8 mAb depletion and adoptive cell transfer experiments. Transfer of hyperimmune serum containing anti-C6VL TCR Abs into na ive mice had modest anti-tumor effects and was not sufficient to prevent tumor growth. TCR-vaccinated B cell-deficient mice were not protected against C6VL tumor, and tumor protection was not completely restored after hyperimmune serum transfer. Thus, B cells may serve as important APCs in inducing a protective immune response. Based on these results future TCR vaccines should be designed to maintain native TCR conformation, as well as induce a strong Th1-type immune response.

Adjuvants, Immunologic↗
PubMed1998

Determination of anti-idiotype antibodies by surface plasmon resonance.

A method based on surface plasmon resonance has been used to detect and to quantitate antibodies against other antibodies. This method has been applied to the detection of syngeneic antibodies. Concentrations as low as 0.3 microg/ml could be detected even when the antibodies were present in undiluted serum. Quantitation of both monoclonal and polyclonal antibodies could be performed. Anti-idiotype antibodies could be detected equally well against an IgM molecule derived directly from the B cell tumour or against a chimeric protein composed of the same idiotypic determinants embedded in a human IgG molecule. Surface plasmon resonance will be the method of choice for the detection of antibody responses in humans vaccinated against idiotypic determinants of their own tumour.

Animals↗
PubMed1998

Comparison of bone single-photon emission tomography and planar imaging in the detection of vertebral metastases in patients with back pain.

Bone scan has long been considered to be an important diagnostic test in searching for bone metastases. However, considerable difficulty is encountered in the vertebral region due to the complexity of structures and the fact that other benign lesions, especially degenerative changes, are very common there. Single-photon emission tomography (SPET) has been reported to be useful in the differentiation of benign from malignant conditions. Here we report our experience with bone SPET in the diagnosis of vertebral metastases. This is a retrospective study of technetium-99m methylene diphosphonate (MDP) bone scans in 174 consecutive patients who were referred for the investigation of back pain in our department. MDP planar and SPET images were obtained. Of teh 174 patients, 98 had a known history of malignant tumours. The diagnosis of vertebral metastasis was made on the basis of the patients' clinical histories and the findings with other imaging techniques such as magnetic resonance imaging, computed tomography or follow-up bone scan. We found that the presence of pedicle involvement as seen on SPET was an accurate diagnostic criterion of vertebral metastasis. SPET had a sensitivity of 87%, a specificity of 91%, a positive predictive value of 82%, a negative predictive value of 94% and an accuracy of 90%. On the other hand, planar study had a sensitivity of 74%, a specificity of 81%, a positive predictive value of 64%, a negative predictive value of 88% and an accuracy of 79% in diagnosing vertebral metastasis. Except with regard to the negative predictive value, SPET performed statistically better than planar imaging. Only 9/147 (6.4%) lesions involving the vertebral body alone and 3/49 (6.1%) lesions involving facet joints alone were subsequently found to be metastases. We conclude that bone SPET is an accurate diagnostic test for the detection of vertebral metastases and is superior to planar imaging in this respect.

Aged↗
PubMed1997

TCR vaccines for active immunotherapy of T cell malignancies.

We have developed a TCR-based vaccine approach for the treatment of T cell malignancies. TCR genes were isolated from C6VL, a T cell tumor of C57BL/Ka origin. The transmembrane encoding domains of the TCR genes were replaced by sequences encoding for phosphatidylinositol-linked cell surface expression. A high expressing cell line was produced by transfection and amplification of the TCR genes. Large quantities of soluble native C6VL TCR-alphabeta protein was obtained by treating the high-expressing cells with a specific phospholipase and purifying the released TCR by affinity chromatography. Following vaccination with the TCR linked to keyhole limpet hemocyanin, specific anti-TCR humoral responses were induced. Both the carrier protein and an adjuvant were required for optimal responses. Hyperimmune serum from vaccinated mice reacted specifically with C6VL cells, and the immunizations did not affect the TCR repertoire, which suggested that the immune response was Id specific. The TCR-vaccinated mice were specifically protected from a lethal number of C6VL tumor cells. B cell-deficient mice were not protected by TCR vaccinations. Similarly, TCR-immunized mice depleted of CD8+ cells prior to tumor challenge were not protected. Thus, C6VL TCR vaccine effectively stimulated tumor protection, which depends on the presence of both B cells and CD8+ T cells.

Animals↗
PubMed1996

The role of the family physician in the day care setting.

Injuries and infectious respiratory, gastrointestinal and dermatologic diseases are common in day care settings. Most day care injuries are contusions, abrasions and cuts involving the head and extremities. Impact-absorbing surfaces under playground equipment, safely-proofing of all play areas, increased staff supervision, and staff and parental education might reduce injuries by as much as 75 percent. Respiratory illnesses are the most common day care infections. Chemoprophylaxis with rifampin is required for all close contacts of children infected with Haemophilus influenzae type B and Neisseria meningitidis. Diarrheal illness may be caused by viral pathogens, bacterial agents such as Shigella, Campylobacter or Salmonella, or parasitic infections caused by Giardia lamblia and Cryptosporidium. Strict hand-washing procedures, especially before food preparation and after toileting, may reduce diarrheal illness by 50 percent. Head lice (Pediculosis capitis) and scabies are common dermatologic infections spread by direct contact and through clothing, bedding and hair brushes. Screening and treating affected children with permethrin preparations and thoroughly washing bedding and clothing are necessary to stop outbreaks. Use of universal precautions for the handling of stool is essential to prevent the spread of both ordinary diarrheal illnesses and serious infections such as hepatitis A and B, human immunodeficiency virus and cytomegalovirus.

Child↗