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Biomedical subjects

R W Wong

Publications and source records attributed to R W Wong.

13 recordsLinked to original sources
PubMed1992

Linkage between rheumatoid arthritis susceptibility and the presence of HLA-DR4 and DR beta allelic third hypervariable region sequences in southern Chinese persons.

OBJECTIVE: To analyze HLA-DR and DQ associations with rheumatoid arthritis (RA) in patients from southern China. METHODS: In 66 patients and 45 controls, restriction fragment length polymorphism studies were performed using DRB, DQA, and DQB probes, and DRB allele-specific typing of polymerase chain reaction-amplified DRB DNA: RESULTS: The frequency of HLA-DR4 was significantly increased among RA patients (42.4% versus 17.8%). Increased frequencies of the DQA3 allele (77.8% versus 48.9%) and the DQB1*0302 allele (71.0% versus 46.3%), which are in linkage disequilibrium with DR4, were also found. Oligonucleotide typing showed that the amino acid sequence LLEQRRAA, spanning amino acid positions 67-74 of the DR beta molecule, was found in 19 of 49 patients and 5 of 32 controls. The main DR4 allelic subtypes found in the population were DRB1*0404 and DRB1*0405, both of which carried the sequence. There was no difference in subtype distribution between patients and controls. CONCLUSION: Chinese RA patients have an increased frequency of HLA-DR4 alleles which possess the same DRB third allelic hypervariable sequence shown to be associated with susceptibility in Caucasian RA patients.

Alleles↗
PubMed1992

Contrast-induced nephrotoxicity: the effects of vasodilator therapy.

The increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with peripheral vascular disease has generated concern about the incidence and avoidance of contrast-induced nephrotoxicity (CIN). In this prospective study, we sought to identify those patients at greater risk of developing CIN and to evaluate the efficacy of vasodilator therapy with dopamine in limiting this complication. Baseline serum creatinine (Cr) concentrations were obtained on admission and daily for up to 72 hr after angiography in 222 patients undergoing 232 angiographic procedures. The preangiographic treatment was varied at 2-month intervals for 1 year. All patients received an intravenous infusion of 5% dextrose and 0.45% normal saline at a rate of 75 to 125 ml/hr. During the first interval patients received 12.5 g of 25% mannitol immediately prior to their contrast load, in addition to intravenous fluids. During the next 2-month period the patients were given renal dose dopamine intravenously (3 micrograms/kg/min) commencing the evening before angiography and continued to the next morning. During the latter half of the study the treatment regimens were modified so that the use of mannitol was restricted to patients with diabetes mellitus and dopamine to patients with serum creatinine concentrations of > or = 2 mg/dl. Postangiographic elevation in Cr occurred in 2, 10.4, and 62% of studies in patients with baseline creatinine levels of < or = 1.2 mg/dl, 1.3 to 1.9 mg/dl, and > or = 2.0 mg/dl, respectively. None of the patients receiving dopamine experienced an elevation in creatinine. There was no statistical correlation between age, diabetes, or medication with calcium channel blockers and CIN.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Aberrant T-regulation in rheumatoid arthritis and IgA nephropathy affects CD5+ and CD5- B lymphocytes equally.

T-suppressor function and T-helper function in healthy adults, elderly patients with non-immune diseases, and patients with rheumatoid arthritis (RA) and IgA nephropathy (IgAN) were titrated by adding graded concentrations of CD8+ cells to autologous CD8-depleted peripheral blood mononuclear cells (PBMC), or CD4+ cells to CD8- 4- PBMC, respectively. Following culture with pokeweed mitogen (PWM), numbers of CD5+ and CD5- immunoglobulin-secreting cells were determined using a combination of rosetting with anti-CD5-coated Dynabeads and reverse haemolytic plaque formation (Jones, 1990). Of 11 RA patients studied, eight had slightly reduced suppressor activity for CD5+ and CD5- IgM-secreting cells, and three with active disease and high serum levels of C-reactive protein, could not suppress IgG, IgA or IgM secretion by either B subset. Helper activity for both CD5+ and CD5- B cells was slightly but significantly increased in RA patients. One of eight patients with IgAN could not suppress IgG, IgA or IgM production by CD5+ or CD5- B cells, and all IgAN patients required strikingly fewer CD4+ cells for PWM-induced activation of CD5+ and CD5- B cells than controls. It was concluded that in two immunologically mediated diseases in which some patients have raised numbers of circulating CD5+ B cells, aberrant T-regulation affects CD5+ and conventional CD5- B cells equally.

Antibody Formation↗
PubMed1991

Immunogenetics in Chinese patients with SLE.

100 consecutive Chinese patients with SLE were recruited for study of HLA-A, B and DR antigen. Clinical and serological parameters were analysed with respect to the HLA antigens. B5 was associated with presence of other autoimmune diseases (thyrotoxicosis, myasthenia gravis, diabetes mellitus, corrected p less than 0.025); absence of malar rash (corrected p less than 0.025); B35, with male sex (corrected p less than 0.025); DR2 with anti-Ro (anti-SSA) antibody (p less than 0.05). Previous study of association with B13, B17 was not present in our cohort. Except for malar rash, subclassification of disease status with respect to HLA antigen did not reveal significant association.

Adult↗
PubMed1991

Neurological manifestations of systemic lupus erythematosus: a prospective study.

A prospective study of the neurological manifestations in all patients with systemic lupus erythematous (SLE) was conducted between February 1985 to January 1989. Excluding herpes zoster infection of peripheral or cranial nerves, post-herpetic neuralgia and migraine, 36 neurological episodes occurred in 33 patients. The presenting symptoms were mental confusion (10), psychosis (five), seizures (six), focal neurological deficit (three), coma (two), headache (five), blurring of vision (three), neuropathy (one) and myelopathy (one). Of these manifestations, only eight episodes were due to primary involvement by SLE: psychosis (two), seizure (two), multiple cerebral infarcts (one), papillitis (one), neuropathy (one) and myelopathy (one). Infection was the most common secondary cause of neurological episodes: all 10 episodes of mental confusion (fungal seven, pyogenic two, tuberculous one, nocardial one); two of six seizures (tuberculous one, pyogenic one); all five headaches (tuberculous meningitis three, cryptococcal meningitis two). The other secondary causes included steroid psychosis (two), hypertensive encephalopathy with seizure (one) and hypertensive retinopathy (one). Three of five cases of focal neurological deficit were due to macrovascular disease rather than to vasculitic infarction. We concluded that cerebral psychosis was a relatively rare presentation in our patients with SLE. In patients who presented with a neurological problem, especially mental confusion, efforts should be made to ascertain the underlying cause, especially if this may be an infection.

Adult↗
PubMed1990

Lack of association between slow acetylator status and spontaneous lupus erythematosus.

The Chinese in Southeast Asia are recognized as a population group that has a relatively high prevalence of rapid "acetylators" and a relatively high incidence of systemic lupus erythematosus. This study was designed to evaluate the possibility that there were environmental lupus erythematosus provocative substances eliminated by acetylation that resulted in a preponderance of slow acetylators among patients with the disease. We compared acetylator status in 36 Chinese women with mild, stable, and confirmed lupus erythematosus and 36 healthy control subjects matched for age, sex, and ethnic origin. Acetylator status was determined by use of HPLC to assay 5-acetylamino-6-formylamino-3-methyluracil/methylxanthine (AFMU/MX) and AFMU/(AFMU + MX) ratios in urine 1 to 4 hours after drinking a strong cup of coffee (caffeine). By use of parametric and nonparametric methods of analysis, the frequency distribution of AFMU/MX and AFMU/(AFMU + MX) ratios in both the patients and control subjects were determined to be very similar. Thus there was no association between slow acetylator status and lupus erythematosus in the study subjects.

Acetylation↗
PubMed1989

Implications of accurate pathologic margins in the treatment of primary breast cancer.

Eighty-seven patients who underwent mastectomy or reexcision following a previous segmental resection with pathologic margins evaluated at that time were restudied following their definitive therapy. Of these, 40 (46.0%) had involved margins, 28 (32.2%) had close margins, and 19 (21.8%) had clear margins. Residual tumor was subsequently found in 21 (52.5%) of 40, nine (32.1%) of 28, and five (26.3%) of 19, respectively. Analysis of specimens for quadrant of residual tumor showed 27 (31.0%) of 87 patients in the same quadrant, and 11 (14.7%) of 75 present in a different quadrant. The assessment of microscopic margins may be misleading since 29.8% (14/47) of patients with clear or close margins subsequently had residual tumor, and 47.5% (19/40) of those with involved margins had no residual tumor found. Further studies are essential to define the optimum guidelines for tumor excision at the time of segmental resection.

Adult↗
PubMed1987

Lupus anticoagulant--a double misnomer.

The clinical features of thirteen Chinese patients with lupus anticoagulant were described. They were noted to conform to those reported among Caucasians and tend to suggest that the term 'lupus anticoagulant' is a double misnomer.

Adult↗
PubMed1987

Strong association between the major histocompatibility complex and systemic lupus erythematosus in southern Chinese.

The distribution of HLA-A, B, and DR alleles has been studied in 100 Chinese patients with systemic lupus erythematosus and in 100 healthy Chinese controls. Complement components factor B, C4A and C4B were studied in 72 patients and 61 controls. There was no significant difference between patients and controls in the distribution of HLA-A, HLA-B, factor B and C4B alleles, but there was a significant excess of HLA-DR2 and C4A null in the patients. An unusual variant of C4B was found in 6 patients and 1 control. The possible role of haplotypes is considered in interpreting these results and relating them to previous findings in Chinese.

Adolescent↗
PubMed1986

Cumulative patency and actual palliation in patients with claudication after aortofemoral bypass. Prospective long-term follow-up of 100 patients.

This report assesses patency, subsequent surgery, and the effect of late mortality in a series of 100 consecutive aortofemoral grafts performed for significant claudication on the basis of aortoiliac occlusive disease. Considering thrombosis or elective revision as failure, the primary patency rate at 5 and 10 years was 84 percent and 78 percent, respectively. However, most of these grafts were easily revised and remained patent for long periods, giving a secondary patency rate of 93 percent at 10 years. But survival is the critical factor in assessing what has really been accomplished for these patients. We believe that this is best expressed by cumulative actual palliation, that is, the patient alive, the graft patent, and the symptoms controlled without amputation. Cumulative actual palliation was approximately 75 percent at 5 years and 50 percent at 10 years. The palliation index (the proportion of living patients who were palliated) was more than 90 percent throughout the first 10 years. These data support the use of aortofemoral grafting in selected patients who suffer from intermittent claudication. Reporting the cumulative actual palliation, palliation index, and salvage index add precise and useful information to cumulative graft patency that disregards the effect of death.

Adult↗
PubMed1986

AIDS in a Hong Kong Chinese.

A young Hong Kong Chinese male patient with fever of unknown origin is presented. The diagnosis of acquired immunodeficiency syndrome was made only 5 months after the onset of his illness. The lack of awareness of the syndrome might account for the delay in the diagnosis. The legal attitude towards homosexuality might have an adverse effect on epidemiological studies of AIDS in Hong Kong.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Cryptic miliary tuberculosis.

Fifteen patients with cryptic miliary tuberculosis seen over a six-year period in a large teaching hospital were reviewed. This form of tuberculosis tended to be difficult to diagnose and was most common in older people and those with underlying diseases such as malignancy or blood dyscrasias. Bacteriological investigation was of the little help in diagnosis while bone marrow and liver biopsies were more useful. The diagnosis was made during life in only seven (47 per cent) of the 15 cases, and the overall mortality was 80 per cent. Tuberculosis should be considered in all cases of pyrexia of unknown origin, and investigations performed to establish or exclude the diagnosis. A prompt and adequate therapeutic trial with antituberculous treatment even in the absence of definite evidence of tuberculosis can be life-saving.

Adolescent↗