Biomedical subjects

A L Wong

Publications and source records attributed to A L Wong.

At least 19 recordsLinked to original sources

PubMed2006

Application of explicit process of care measurement to rheumatoid arthritis: Moving from evidence to practice.

OBJECTIVE: To construct quality measures with measurement validity and meaning for clinicians. METHODS: We conducted a prospective cohort study of rates of change in disease-modifying antirheumatic drug (DMARD) and/or systemic corticosteroid drug or dose for 568 patients with rheumatoid arthritis (RA) across 6,159 clinical encounters within 12 months to examine how changes in clinical specifications change adherence. RESULTS: Rates of DMARD change were sensitive to specifications regarding the intensity of disease activity (severe or moderate), duration of specified disease activity, and length of the observation period. Over 12 months, the proportions of 377 patients with severe disease activity observed for 1-month, 2-month, and 3-month time blocks who had a change in DMARD drug or dose were 36%, 57%, and 74%, respectively. Over 12 months, a change in DMARD drug or dose was observed for 44%, 50%, and 68% of 377 patients with severe disease within 3 months, 6 months, and 12 months, respectively, of the patient meeting criteria for severe disease activity. A change in DMARD drug or dose was observed for 21%, 23%, and 34% of 149 patients with moderate disease activity within 3, 6, and 12 months, respectively, of the patient meeting criteria for moderate disease activity. CONCLUSION: Rates of pharmacologic interventions for patients with moderate and severe RA disease activity vary substantially by intensity and duration of disease activity and by duration of period for observing change. Lack of precision in explicit process criteria could substantially mislead comparisons of quality of care across comparison groups.

Adrenal Cortex Hormones↗

PubMed2006

The application of a vacuum-ultraviolet Fourier transform spectrometer and synchrotron-radiation source to measurements of bands of NO. VII. The final report.

Photoabsorption measurements of NO bands have been made by vacuum-ultraviolet Fourier transform spectrometry with a resolution of 0.12 cm(-1) in the wavelength region of 166.2-196.2 nm. Accurate line positions are obtained for the delta(upsilon,0) bands with upsilon=2, 3, the epsilon(upsilon,0) bands with upsilon=2, 3, and the beta(upsilon,0) bands with upsilon=10,12,14. Absolute term values are found for the corresponding upper levels C(2,3), D(2,3), and B(10,12,14). Accurate rotational line integrated cross sections have also been obtained for the lines in these bands. Integrated cross sections reported in our earlier papers [J. Chem. Phys. 109, 1751 (1998); 112, 2251 (2000); 115, 3719 (2001); 116, 155 (2002); 117, 10621 (2002); 119, 8373 (2003)] have been revised, and the results reported here comprise the delta(upsilon,0) bands with upsilon=0-3, the epsilon(upsilon,0) bands with upsilon=0-3, the beta(upsilon,0) bands with upsilon=6,7,9-12,14, and the gamma(3,0) band. For each band, the band oscillator strength is obtained from the sum of the line strengths of all rotational lines, and these are compared with other published values.

Journal Article↗

PubMed2006

Combined photodynamic therapy and intravitreal triamcinolone injection for the treatment of subfoveal choroidal neovascularisation in age related macular degeneration: a comparative study.

AIM: To evaluate the outcomes of combined intravitreal triamcinolone (IVTA) and photodynamic therapy (PDT) with verteporfin in the treatment of subfoveal choroidal neovascularisation (CNV) caused by age related macular degeneration (AMD). METHODS: 48 eyes from 48 patients with subfoveal CNV caused by AMD were prospective recruited, with 24 eyes treated with combined PDT with IVTA and compared with a control group of 24 eyes which received PDT monotherapy. In the combined treatment group, IVTA was performed immediately after PDT as an outpatient procedure. The mean number of treatments, mean logMAR best corrected visual acuity (BCVA), mean line of visual acuity changes, and proportion of patients without moderate visual loss at 1 year were compared between the combined and monotherapy groups. RESULTS: At 1 year the logMAR BCVA for the PDT with IVTA group changed from 0.88 to 0.95 (p = 0.32 compared with baseline), whereas the logMAR BCVA for the monotherapy group reduced from 0.74 to 1.09 (p<0.001 compared with baseline). A significantly higher proportion of patients who had PDT with IVTA did not develop moderate visual loss at 1 year compared with the monotherapy group (70.8% and 33.3% respectively, p = 0.009). Eyes which had combined treatment had significantly fewer lines lost compared with monotherapy alone (0.7 and 3.5 lines respectively, p = 0.015). Subgroup analysis showed that PDT with IVTA is effective in preventing visual loss in both predominately classic and occult CNV groups. The mean number of treatments for the combined and monotherapy groups was 1.5 and 1.96 respectively (p = 0.076). CONCLUSIONS: Combined PDT with IVTA appeared more effective statistically at 12 months for stabilisation of vision (<3 logMAR lines change) compared with PDT monotherapy. Further randomised control trials might be justified to conclude the efficacy of PDT with IVTA.

Aged↗

PubMed2001

Differentiating osteomyelitis from bone infarction in sickle cell disease.

This brief review discusses one possible approach to evaluating the sickle cell patient with bone pain. The major differential diagnoses include osteomyelitis and bone infarction. Based on previous studies, we provide an approach to assessing and treating patients with the possible diagnosis of osteomyelitis. An algorithm has been provided, which emphasizes the importance of the initial history and physical examination. Specific radiographic studies are recommended to aid in making the initial assessment and to determine whether the patient has an infarct or osteomyelitis. Differentiating osteomyelitis from infarction in sickle cell patients remains a challenge for the pediatrician. This algorithm can be used as a guide for physicians who evaluate such patients in the acute care setting.

Acute Disease↗

PubMed2001

HELLP-like syndrome associated with hepatic necrosis in a patient with systemic lupus erythematosus.

Hemolysis, elevated liver enzymes, and low platelet (HELLP) syndrome is often associated with preeclampsia or hypertension in pregnancy. Pregnancy in patients with systemic lupus erythematosus (SLE) may be complicated by development of a lupus flare with thrombocytopenia, hypertension and renal insufficiency, which may be difficult to distinguish from preeclampsia. We describe a 20-year-old patient with SLE and anticardiolipin antibodies who developed a HELLP-like syndrome during 2 successive pregnancies without the more typical symptoms of preeclampsia or hypertension. This unusual presentation of HELLP syndrome during pregnancy in a patient with SLE was evidenced by hematologic and liver enzyme abnormalities as a sign of ongoing hepatic necrosis. Early recognition of this syndrome is important because it may result in rapid deterioration with progressive hepatic necrosis that can be reversible with early termination of pregnancy.

Journal Article↗

PubMed2001

Circulating antibodies to guanosine in systemic lupus erythematosus: correlation with nephritis and polyserositis by acute and longitudinal analyses.

Systemic lupus erythematosus (SLE) is characterized by autoantibodies, including antibodies to the nucleosides of DNA. Guanosine is the most immunogenic nucleoside. In this study serum antiguanosine antibody levels were compared with disease activity, determined by their SLEDI score, in 86 patients with SLE. Sera from these patients were tested, by ELISA, for autoantibodies to guanosine, single-stranded DNA (ssDNA), and double-stranded DNA (dsDNA). Anti-double-stranded DNA levels were also measured by RIA. Resultant values from these assays were correlated with SLE disease activity, and compared with specific features of SLE. The strongest correlation was higher levels of antiguanosine antibodies in patients with active lupus nephritis and polyserositis compared to patients with inactive disease (P < 0.0001). Antiguanosine levels also correlated with arthritis (P < 0.006), CNS lupus (P < 0.005), and hematologic manifestations of SLE (P < 0.002). To test the validity of this association in chronic SLE, serum antiguanosine antibodies were measured in patients with SLE at various phases of disease activity. Twelve patients with SLE had serum samples drawn at active, active-improved, and inactive phases over a 3-7 y period. Differences were significant for serum antiguanosine antibodies in the active group compared to the inactive group (P < 0.05) and the active vs the active-improved group (P < 0.02), unlike those for dsDNA and ssDNA by ELISA or RIA. Antiguanosine antibodies correlated more closely with disease activity in SLE patients in this longitudinal study than either anti-dsDNA or ssDNA antibodies. Thus, antibodies to guanosine correlated as well or better with disease activity than the other anti-DNA antibodies measured and should be considered to contribute to the pathology of SLE, especially lupus nephritis.

Acute Disease↗

PubMed2001

Acute appendicitis in an incarcerated inguinal hernia.

A preterm infant with acute appendicitis in an incarcerated inguinal hernia is described. We suggest that extraluminal compression of the neck of a hernial sac caused by incarceration may be a predisposing factor for appendicitis.

Appendicitis↗

PubMed2000

Microbial production of polyhydroxyalkanoates by bacteria isolated from oil wastes.

A Gram-positive coccus-shaped bacterium capable of synthesizing higher relative molecular weight (M(r)) poly-hydroxybutyrate (PHB) was isolated from sesame oil and identified as Staphylococcus epidermidis (by Microbial ID, Inc., Newark, NJ). The experiment was conducted by shake flask fermentation culture using media containing fructose. Cell growth up to a dry mass of 2.5 g/L and PHB accumulation up to 15.02% of cell dry wt was observed. Apart from using single carbohydrate as a sole carbon source, various industrial food wastes including sesame oil, ice cream, malt, and soya wastes were investigated as nutrients for S. epidermidis to reduce the cost of the carbon source. As a result, we found that by using malt wastes as nutrient for cell growth, PHB accumulation of S. epidermidis was much better than using other wastes as nutrient source. The final dried cell mass and PHB production using malt wastes were 1.76 g/L and 6.93% polymer/cells (grams/gram), and 3.5 g/L and 3.31% polymer/cells (grams/gram) in shake flask culture and in fermentor culture, respectively. The bacterial polymer was characterized by 1H-nuclear magnetic resonance (NMR), 13C-NMR, Fourier transform infrared, and differential scanning calorimetry. The results show that with different industrial food wastes as carbon and energy sources, the same biopolymer (PHB) was obtained. However, the use of sesame oil as the carbon source resulted in the accumulation of PHB with a higher melting point than that produced from other food wastes as carbon sources by this organism under similar experimental conditions.

Carbohydrate Metabolism↗

PubMed2000

House dust mite fauna in the Klang Valley, Malaysia.

Allergy to house dust mites (HDM) is an important cause of asthma and rhinitis in Malaysia. This study was carried out to evaluate the dust mite fauna in the Klang Valley. Dust samples were collected from 20 houses from March 1994 to February 1995. Thirty-three dust samples from mattresses were examined monthly for the occurrence of HDM. A total of 22 species in 9 families of HDM was identified. The most common and densely populated species was Blomia tropicalis with an average density of 8,934 mites/g of dust. Dermatophagoides pteronyssinus was the next in abundance, followed by Malayoglyphus intermedius. All houses surveyed were found to be infested with HDM and every house had at least 6 species of HDM. B. tropicalis and D. pteronyssinus were found in all mattresses. HDM in the Klang Valley were found to be highly prevalent and present in high densities. In this study, counts of D. pteronyssinus was found to exceed the proposed exposure threshold of 500 mites/g dust, for triggering acute asthma. Although counts of B. tropicalis exceeded D. pteronyssinus, no conclusion could be made because there is currently no exposure threshold for triggering acute asthma, for this species. Monthly distribution of B. tropicalis and D. pteronyssinus showed 2 peaks and 4 peaks, respectively. The major peak for D. pteronysinus was in January 1995 whereas for B. tropicalis, the major peak was more variable and occurred between November 1994 to January 1995. Both the species showed minor peak in April 1994.

Air Pollution, Indoor↗

PubMed1999

Patient self-report tender and swollen joint counts in early rheumatoid arthritis. Western Consortium of Practicing Rheumatologists.

OBJECTIVE: To determine the correlation between patient self-report joint counts and standard physician joint counts, and to compare pictorial (Mannequin) and text (Rapid Assessment of Disease Activity in Rheumatology, RADAR) formats for obtaining patient self-reports. METHODS: Baseline patient self-report joint counts were mailed and completed by 60 patients with early rheumatoid arthritis (RA) one day before and one day after being examined by a physician. Twenty-seven were randomized to the Mannequin tender and Mannequin swollen joint counts; 33 were randomized to the RADAR tender and swollen joint counts. Agreement between patient and physician self-report joint counts, diagnostic characteristics, and test-retest reliability of patient self-report joint counts was computed. Stepwise regression analyses were performed to identify predictors of patient-physician differences in total joint count. RESULTS: Means and standard deviations of paired patient and physician total joint counts were not different for Mannequin or RADAR forms. Spearman correlations were moderate (0.58 to 0.69 for Mannequin, 0.37 to 0.58 for RADAR). Agreement (intraclass correlations) was 0.65 for the Mannequin and 0.56 for the RADAR forms. Patient test-retest reproducibility was moderate for RADAR tenderness (0.58) and high (r>0.90) for RADAR swollen and both Mannequin forms. Level of patient education predicted patient-physician differences on the RADAR swollen joint counts (p = 0.003), but was not significant in Mannequin forms, suggesting that education was not a factor in accurate completion of Mannequin forms. CONCLUSION: Both pictorial and text format patient self-report joint counts are significantly correlated with physician joint counts. In addition to moderately high patient test-retest reproducibility, this suggests that patient self-reports in both formats may yield accurate measures of improvement in disease activity.

Adult↗

PubMed1997

Tie2 expression and phosphorylation in angiogenic and quiescent adult tissues.

Angiogenesis, the process of new vessels sprouting from the existing vasculature, is a critical process during early development. However, angiogenesis rarely occurs in the adult, except in response to cyclic hormonal stimulation in the ovary and uterus, in response to injury, and in response to pathological conditions such as tumorigenesis and diabetes mellitus. Tie2 (also known as Tek) is a novel endothelium-specific receptor tyrosine kinase, which has been demonstrated to be essential for the development of the embryonic vasculature; Tie2 knockout mice die by embryonic day 10.5 with specific defects in the formation of microvessels. Tie2 is downregulated later in embryogenesis, and its function in the adult has been relatively unexplored. To gain insight into the potential functions of Tie2 in the adult vasculature, Tie2 expression was examined in adult tissues undergoing angiogenesis and in quiescent tissues. Tie2 expression was localized by immunohistochemistry to the endothelium of neovessels in rat tissues undergoing angiogenesis during hormonally stimulated follicular maturation and uterine development and in healing skin wounds. Immunoprecipitation and RNase protection assay demonstrated upregulation of Tie2 protein and mRNA in rat and mouse skin wounds, respectively. Moreover, Tie2 immunoprecipitated from skin wounds was tyrosine-phosphorylated, indicating active downstream signaling. Surprisingly, Tie2 was also expressed in the entire spectrum of the quiescent vasculature (arteries, veins, and capillaries) in a wide range of adult tissues, and Tie2 immunoprecipitated from quiescent adult tissues was also tyrosine-phosphorylated. Together, these results suggest a dual function for Tie2 in adult tissues involving both angiogenesis and vascular maintenance.

Aging↗

PubMed1996

Mechanisms of cellular penetration and nuclear localization of an anti-double strand DNA autoantibody.

An anti-dsDNA Ab, mAb 3E10, was identified that bound membranes of fixed human renal tubular cells, penetrated live murine renal tubular cells in vivo, and localized in the cell nucleus. mAb 3E10 binds both dsDNA and an extracellular matrix protein, HP8/HEVIN, expressed in high endothelial venules. Previous studies showed both shared and distinct binding determinants of mAb 3E10 VH for DNA and HP8/HEVIN. To independently assess the requirement of DNA and HP8/HEVIN in cellular penetration, site-directed mutants of mAb 3E10 VH and V kappa were studied for penetrating kidney cell lines. The results showed that residues required for binding DNA, but not HP8/HEVIN, were necessary for Ab penetration, indicating that cellular penetration required the presence of DNA or binding of Ab to a membrane determinant precisely resembling DNA. Ab Fab penetrated cells, indicating that neither the Fc nor multivalent Ab binding is necessary for cellular penetration. Ab synthesized in the cytoplasm as a result of deleting heavy and light chain signal peptides was not translocated to the nucleus, indicating a mechanism distinct from the usual protein nuclear localization signals and suggesting the need for a membrane-mediated pathway or for post-translational modification of the Ab.

Animals↗

PubMed1996

Effects of renin gene transfer on blood pressure and renin gene expression in a congenic strain of Dahl salt-resistant rats.

To investigate whether a BP-regulatory locus exists in the vicinity of the renin locus on rat chromosome 13, we transferred this chromosome segment from the Dahl salt-sensitive (S) rat onto the genetic background of the Dahl salt-resistant (R) rat. In congenic Dahl R rats carrying the S renin gene and fed an 8% salt diet, systolic BP was significantly lower than in progenitor Dahl R rats: 127 +/- 1 mmHg versus 138 +/- 4 mmHg, respectively (P < 0.05). Moreover, the decreased BP in the congenic Dahl R strain was associated with decreased kidney renin mRNA and decreased plasma renin concentration. These findings demonstrate that the Dahl S strain carries alleles in or near the renin locus that confer lower plasma renin concentration and lower BP than the corresponding alleles in the Dahl R strain, at least when studied on the genetic background of the Dahl R rat and in the environment of a high salt diet. The occurrence of coincident reductions in kidney renin mRNA, plasma renin concentration, and BP after interstrain transfer of naturally occurring renin gene variants strongly suggests that genetically determined variation in renin gene expression can affect BP.

Alleles↗

PubMed1996

A review of computed tomography in the diagnosis of intestinal and mesenteric injury in pediatric blunt abdominal trauma.

OBJECTIVE: To determine the sensitivity, specificity, and positive and negative predictive values of the computed tomography (CT) scan in the diagnosis of clinically significant intestinal and mesenteric injury in pediatric blunt abdominal trauma. PATIENTS: The records of 145 children who presented to a tertiary care pediatric hospital between 1987 and 1994 were reviewed retrospectively. All had experienced single or multiple injuries and underwent CT as part of the trauma assessment. METHODS: The patients were divided into two cohorts, based on the results of the initial CT scan: either positive (n = 20) or negative (n = 152) for evidence of intestinal or mesenteric injury. The two cohorts were similar with respect to age, trauma score, and timing of CT scan. The outcome of surgical (n = 23) and conservative management (n = 122) was compared with the initial CT scan results. (Some of the laparotomies were for solid-organ injury only.) RESULTS: The sensitivity of the CT scan in the diagnosis of clinically significant intestinal and mesenteric injury is 0.93. The specificity and positive and negative predictive values are 0.95, 0.65, and 0.99, respectively. CONCLUSION: The CT scan is an excellent test to screen for clinically significant intestinal and mesenteric injury in pediatric patients with blunt abdominal trauma. Because of the lower positive value, other clinical and diagnostic imaging information may help to improve diagnostic accuracy. Most importantly, CT rarely misses a significant intestinal or mesenteric injury.

Abdominal Injuries↗

PubMed1995

Localization of an Fc-binding reactivity to the constant region of human IgG4. Implications for the pathogenesis of rheumatoid arthritis.

The majority of plasma cells in rheumatoid arthritis (RA) synovium produce rheumatoid factors (RF). IgG RF predominate in the immune complexes found in RA synovial fluid and have been implicated in the pathogenesis of RA. IgG4 RF are a major component of IgG RF produced in serum and synovium of RA patients, even though this subclass comprises only 4% of the serum IgG. We produced an IgG4 mAb, hRF-1, with RF reactivity from the synovial tissue of a patient with RA. mAb hRF-1 had binding specificity for mammalian IgG similar to Staphylococcus aureus protein A, which is characteristic of RF from patients with RA. To determine the molecular basis of this particular RF reactivity, the heavy and light chain genes of mAb hRF-1 were amplified by PCR, cloned, and ligated into the pSG5 plasmid for expression in COS-7 cells. Chain recombination experiments localized the Fc-binding reactivity to the hRF-1 heavy chain. Using a series of chimeric Ab sequences, the Fc-binding reactivity was mapped to the constant region of IgG4 rather than the variable region involved in classic RF reactivity. Multiple domains, including Hinge, CH2, and CH3 of the IgG4 constant region were required for Fc binding. Our studies demonstrate an example of RF-like Fc-binding reactivity that is conferred by the gamma-4 constant region rather than the classic Ag binding site and suggest that increased production of IgG4 may contribute to the pathogenesis of RA.

Amino Acid Sequence↗

PubMed1995

DNA mimics a self-protein that may be a target for some anti-DNA antibodies in systemic lupus erythematosus.

Recent studies suggest that some anti-DNA Abs in systemic lupus erythematosus may actually be Abs to specific proteins and that binding to dsDNA is a nonspecific cross-reactive event. To identify such proteins that bind to anti-DNA Abs, a cDNA expression library from human placenta was screened with mAb 3E10, a pathogenic anti-dsDNA Ab. MAb 3E10 was shown to bind to a 44-amino-acid fragment of HP8, a newly identified protein with amino acid sequence homology to the family of SPARC extracellular matrix proteins. To determine if Ab binding to both dsDNA and HP8 protein occurs through a common binding site, and therefore represents molecular mimicry, the Ab binding domains for protein and DNA were mapped. Chain recombinations between mAb 3E10 and a non-anti-DNA mAb showed that both the heavy and the light chains of mAb 3E10 were essential for anti-dsDNA and anti-HP8 reactivity. Mutagenesis experiments demonstrated that dsDNA and HP8 shared several critical binding residues located in all three complementarity-determining regions of mAb 3E10 VH. Moreover, Abs to HP8 were demonstrated in the sera of a subset of lupus patients. These results indicate that DNA mimics the HP8 protein in binding a lupus Ab, and that this protein may be a target for a subpopulation of anti-dsDNA Abs in systemic lupus erythematosus.

Animals↗

PubMed1995

Two kappa immunoglobulin light chains are secreted by an anti-DNA hybridoma: implications for isotypic exclusion.

An anti-DNA hybridoma derived from an MRL/lpr mouse secretes two different kappa light chains in combination with a single heavy chain. Multiple single cell clones express and secrete immunoglobulin containing both kappa light chains. The N-terminal protein sequences of the light chains correspond to sequences predicted from functionally rearranged mRNAs subjected to reverse transcription and amplified by polymerase chain reaction (PCR). Karyotype analysis of the hybridoma indicates a clonal line derived from the fusion of two cells. By amino acid sequence comparison and PCR analysis, both functional kappa light chains are derived from the MRL/lpr spleen. The two functional light chain cDNAs were cloned and co-transfected into COS-7 cells with the heavy chain cDNA. Only one of the light chains in combination with mAb 3E10 heavy chain confers anti-DNA reactivity. The presence of two separate kappa light chains and, therefore, two separate antigen receptors on a single B cell may have ramifications for both polyclonal activation and toleration of lupus B cells.

Amino Acid Sequence↗

PubMed1995

Ectopic thyroid gland simulating a thyroglossal duct cyst: a case report.

There have been many reports of the inadvertent removal of an ectopic thyroid gland that was mistaken for a thyroglossal duct cyst. The differentiation of these two conditions is extremely important, because inadvertent removal of an ectopic thyroid gland may result in profound hypothyroidism. The authors report the case of a 5-year-old girl with an ectopic thyroid gland in whom the preliminary diagnosis was a thyroglossal duct cyst. They review the embryologic features in the development of an ectopic thyroid gland and discuss an approach to the management of this congenital anomaly.

Child, Preschool↗