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Biomedical subjects

T Kwong

Publications and source records attributed to T Kwong.

At least 19 recordsLinked to original sources
PubMed1999

The specificity of synovial IgM rheumatoid factors (RF) for genetically engineered IgG antibodies is not affected by the method used to immortalize RF-producing B cells.

Previously, we have shown that some rheumatoid factors (RFs) produced by Epstein-Barr virus (EBV)-transformed B cells from patients with rheumatoid arthritis (EBV-RA-RF) appear to be disease-specific autoantibodies that bind differently to defined epitopes on genetically engineered IgG antibodies, compared with RFs expressed by patients with Waldenstrom's macroglobulinaemia (Wmac-RFs) and healthy immunized donors (HID-RFs). To exclude the possibility that EBV transformation is responsible for these differences, we have now studied 15 other monoclonal IgM RFs from patients with RA that were produced by heterohybridoma-B-cell fusion (HRA-RFs). These HRA-RFs show the same gross specificity profiles for IgG as do their EBV-RA-RF counterparts. However, when the specificities of the HRA-RF and EBV-RA-RF panels were combined and compared with those RFs from patients with Wmac or HID, significant differences in binding specificity were again observed. Hybrid IgG3/4 antibodies made by exon shuffles between the IgG3 and IgG4 wild-type genes, and families of IgG variant antibodies made by site-directed mutagenesis, were used to map the fine specificity of HRA-RFs. The fine specificity of HRA-RFs were also similar to those of EBV-RA-RFs. These studies demonstrate that the method used for immortalizing IgM, RF-producing B cells from RA patients does not influence the specificity of the RFs obtained. Furthermore, some RFs expressed in RA have distinct and unique specificities, and may therefore represent disease-specific autoantibodies.

Animals↗
PubMed1995

Effects of dietary modification and fish oil supplementation on dyslipoproteinemia in pediatric systemic lupus erythematosus.

OBJECTIVE: To determine if a program of dietary modification and fish oil supplementation is effective in treating the dyslipoproteinemia in pediatric systemic lupus erythematosus (SLE). METHODS: Prospective clinical trial where each patient serves as his/her own control. Twenty-four consecutive adolescents fulfilling SLE classification criteria were screened with fasting lipid profiles. Patients were identified as having dyslipoproteinemia of active disease or of corticosteroid therapy. Patients were treated for 6 weeks with dietary modification and if dyslipoproteinemia did not normalize with another 6 weeks of dietary modification and fish oil supplementation. RESULTS: Seventeen patients (71%) had dyslipoproteinemia; 10 of active disease, 4 of steroid therapy; 3 with a combined pattern. Eleven patients underwent dietary modification. There was a significant decrease in serum triglyceride concentrations (p < 0.05). Total cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol did not change significantly. A further significant decline in serum triglycerides was achieved with fish oil supplementation (p < 0.05). Five of the 11 patients who underwent treatment continued to have dyslipoproteinemia. CONCLUSION: Dyslipoproteinemia is common in pediatric SLE. Dietary modification and fish oil supplementation appear to be effective in improving serum lipid profiles, and blinded studies are warranted. a significant number of patients may require pharmacologic therapy for persistent dyslipoproteinemia to prevent complications of premature atherosclerosis.

Adolescent↗
PubMed1994

Systemic necrotizing vasculitis associated with childhood sarcoidosis.

Childhood sarcoidosis is a rare disorder with protean manifestations. The case of a child with prolonged fever, hepatosplenomegaly, pancytopenia, and systemic necrotizing vasculitis manifesting as fever, rash and skin infarctions, digital pregangrene, and foot drop is reported. This is the first case of systemic necrotizing vasculitis reported in sarcoidosis. The fulminant course of the disease required treatment with intravenous pulsed cyclophosphamide and high doses of corticosteroids. The spectrum of vasculitis in childhood and adult sarcoidosis is reviewed.

Bone Marrow↗
PubMed1994

Meconium analysis for improved identification of infants exposed to cocaine in utero.

We screened anonymously all mothers and infants born during a 3 1/2-month period to determine the prevalence of intrapartum cocaine use, test the maternal characteristics that are specific predictors of intrauterine cocaine exposure (IUCE), and compare the sensitivity of infant urine versus meconium samples for identification of IUCE. Of 1237 live births during the study period, a sample was obtained from 1201 mother-infant pairs. The overall prevalence of documented intrapartum cocaine exposure was 66 (5.5%) of 1201 pairs. Previously developed drug screening guidelines had a sensitivity of 89% for detecting IUCE in infants. Direct comparisons of samples from the same mother-infant pair revealed that there were no cases in which cocaine was found in infant urine but not in meconium; however, infant urine testing missed 25% of the infants who had positive findings in meconium. We conclude that (1) meconium testing was more likely than urine testing to identify an infant with IUCE, detecting an additional 33%; (2) there was significant maternal cocaine use (5.5%) in a teaching hospital with a mixed patient population; (3) maternal characteristics known to identify infants at risk of having IUCE were useful in our population; and (4) IUCE of neonates admitted to the neonatal intensive care unit was more common than that of infants admitted to the regular newborn nursery.

Cannabis↗
PubMed1992

Polyarteritis associated with Yersinia enterocolitica infection.

A patient developed polyarteritis, predominantly affecting the muscles, 10 days after a Yersinia enterocolitica O:3 infection. Immunoperoxidase staining showed Yersinia enterocolitica O:3 antigen in the subendothelial layer of the blood vessels. This suggests that vasculitis should be considered as a rare manifestation of Yersinia enterocolitica infection.

Adult↗
PubMed1990

The use of water as a diluent for bronchodilator nebuliser solutions.

Inhalation of nebulised water can provoke bronchoconstriction in asthmatic patients. In the first part of this study, a community survey identified that about 20% of patients with home nebulisers currently use water as a diluent. In the second part of this study, the airways effect of the use of water as a diluent for nebulised beta agonist was investigated. Nineteen asthmatic subjects were administered nebulised 2.5 mg salbutamol, diluted with either 2 mL water or physiological saline, and forced expiratory volume in one second (FEV1) was measured at baseline and at regular intervals for 45 minutes after nebulisation. Although there was a trend towards a reduced bronchodilator response with water as diluent, the differences between the two diluents were not significantly different. Paradoxical bronchoconstriction was not observed when salbutamol was diluted with water. We conclude that the common practice of diluting bronchodilator nebuliser solution with water does not result in a significant reduction in the overall bronchodilator response.

Adult↗
PubMed1990

Emphysematous pyelonephritis: case report.

We report a case of emphysematous pyelonephritis in a diabetic patient with some atypical features with a successful surgical outcome. This uncommon complication should be considered in any diabetic patient with fulminant or resistant pyelonephritis.

Diabetes Mellitus, Type 2↗
PubMed1990

The self-administration of inhaled beta agonist drugs during severe asthma.

Interviews were conducted with 101 consecutive adult patients admitted to Wellington Hospital with a diagnosis of asthma to assess the extent to which beta agonist drugs are self-administered by asthmatic patients during severe asthma. The 99 patients prescribed an inhaled beta agonist were subdivided into two groups: group A comprising 79 patients prescribed a beta agonist for inhalation via an inhaler (metered dose aerosol or dry powder device) alone; group B comprising 20 patients prescribed beta agonist for inhalation via both an inhaler and nebuliser. In group A, the attacks of asthma lasted greater than 24 hours in 64/79 patients, and 22% of these patients reported taking more than 60 doses of their inhaler, and 52% more than 30 doses during the 24 hr period prior to admission. In group B, the attacks of asthma lasted greater than 24 h in 17/20 patients, and 35% of these patients self-administered their nebuliser more than six times, and 76% more than four times during the 24 h period prior to admission. In addition to their nebuliser use, these patients also took a median 23 doses of their inhaler during this 24 h period. This use of inhaled beta agonist contrasts with the recommended practice in both the USA and Europe, where most physicians recommend no more than 15 doses of a beta agonist as the maximal dose per day. We conclude that asthmatic patients in New Zealand self-administer high doses of inhaled beta 2 agonist drugs during severe exacerbations of asthma.

Adolescent↗
PubMed1990

The cardiovascular effects of beta adrenergic agonist drugs administered by nebulisation.

The cardiovascular effects of equal doses (5 mg) of nebulised fenoterol, salbutamol and terbutaline were compared in 12 healthy individuals in a double-blind, placebo-controlled study. Measurements of heart rate, blood pressure, systolic time intervals, QTc interval and T-wave amplitude were made at baseline and at 15, 30, 45, 60 and 90 minutes after nebulisation. Fenoterol caused significantly greater chronotropic electrocardiographic and inotropic effects than either salbutamol or terbutaline. The peak effects after terbutaline occurred later than those after fenoterol or salbutamol.

Adult↗
PubMed1990

Use of a management plan for treating asthma in an emergency department.

A standardised management protocol has been developed for the assessment and treatment of adults with acute asthma attending an emergency department. The management protocol consists of an assessment sheet for recording essential features of the history and examination findings and a flow diagram with guidelines for initial management that were based on spirometric recordings. The protocol was introduced at Wellington Hospital in 1986. The effect of this intervention was assessed by analysing emergency department records during the three months before and one year after the introduction of the protocol. The use of the assessment sheet improved history taking and led to the increased use of serial measures of airflow obstruction and improved documentation of follow up arrangements. The provision of management guidelines influenced the emphasis of management, including an increased use of corticosteroids intravenously and more frequent use of an additional dose of nebulised bronchodilator. In the light of the initial experience the protocol has been modified and its use either in an emergency department or in general practice is recommended.

Acute Disease↗
PubMed1989

A study of the management of asthma in a hospital emergency department.

We reviewed the medical assessment and treatment of 108 consecutive adult asthmatic patients who attended the Wellington Hospital emergency department for treatment of asthma. Almost 90% of these patients were self referred. Systemic corticosteroids were administered or increased in dose during this asthma attack in only 14% of the 93 patients in whom prior drug therapy was recorded. In the emergency department measurement of either peak expiratory flow or forced expiratory volume in one second was made before treatment in 89% of patients, and after treatment in 77%. About 50% received systemic corticosteroids during their attendance, and of the 66 who were subsequently discharged, 40% were prescribed oral prednisone. Communication with general practitioners concerning patients discharged was poor. We conclude that although the medical assessment and management of severe asthma in this emergency department was of a high standard, there were problems relating to the increased reliance by asthmatic patients on this hospital based service.

Acute Disease↗
PubMed1989

Prescribed fenoterol and death from asthma in New Zealand, 1981-83: case-control study.

A case-control study was conducted to examine the hypothesis that fenoterol by metered dose inhaler (MDI) increases the risk of death in patients with asthma. The case group comprised 117 patients aged 5-45 who died of asthma between August, 1981, and July, 1983. For each case, 4 controls, matched for age and ethnic group, were selected from asthma admissions to hospitals to which the cases themselves would have been admitted, had they survived. The relative risk of asthma death in patients prescribed fenoterol by MDI was 1.55 (95% CI 1.04-2.33, p = 0.03). The possibility of confounding or effect modification by severity was assessed by consideration of subgroups defined by markers of asthma severity. The fenoterol MDI relative risk was 2.21 (95% CI 1.26-3.88, p = 0.01) in patients prescribed three or more categories of asthma drugs, 2.16 (95% CI 1.14-4.11, p = 0.02) in patients with a hospital admission for asthma during the previous 12 months, and 6.45 (95% CI 2.72-15.3, p less than 0.01) in patients prescribed oral corticosteroids at time of death or admission. In the group of patients with the most severe asthma (defined by a hospital admission during the previous year and prescription of oral corticosteroids) the fenoterol MDI relative risk was 13.29 (95% CI 3.45-51.2, p less than 0.01). After adjustment for severity, no other asthma treatment commonly used in New Zealand seemed to be associated with an increased risk of asthma death. Not all sources of bias can be definitely excluded; however, when considered together with other epidemiological and experimental evidence, these findings are consistent with the hypothesis that use of fenoterol by MDI increases the risk of death in severe asthma.

Acute Disease↗
PubMed1984

Rapid determination of salicylate in serum on a centrifugal analyzer.

A bichromatic method is described for the determination of salicylate using a micro centrifugal analyzer. Salicylate was quantitated based on its reaction with ferric ion to produce a violet-colored complex. The method provides sample blanking and allows for rapid determination of salicylate levels in serum.

Bilirubin↗
PubMed1984

Influence of phenytoin on theophylline clearance.

The influence of phenytoin on theophylline elimination was studied in six healthy, nonsmoking subjects who were not taking any other drugs. Subjects were given an intravenous infusion of theophylline (aminophylline), 5 mg/kg, and several blood specimens were drawn over the following 24 hr for theophylline concentration determination. Subjects then began a 2-wk course on oral phenytoin, 300 mg/day, and on day 15 were again challenged with theophylline. For each subject theophylline clearance (ClT) was greater when taking phenytoin (range 31% to 65%). Mean ClT of the six subjects was 45% greater when taking phenytoin than when not taking phenytoin. In one subject, 24-hr urine collections were obtained in the untreated and treated state for analysis of theophylline metabolites. These results showed a general increase in excretion for each of the three major theophylline metabolites in the phenytoin pretreated state compared to the control state. Results indicate that phenytoin increases theophylline elimination. Patients taking phenytoin may require larger theophylline doses than recommended to achieve therapeutic blood theophylline concentrations.

Adult↗
PubMed1983

Age and prior caffeine use alter the cardiovascular and adrenomedullary responses to oral caffeine.

The effects of age and chronic caffeine use (approximately 300 mg/day) on the cardiovascular and humoral responses to 250 mg of oral caffeine (the equivalent of 2 to 3 cups of coffee) were examined. Older subjects had greater increases in blood pressure than younger subjects (p less than 0.03), and caffeine nonusers had greater blood pressure increases than caffeine users, regardless of age (p less than 0.05). Caffeine increased the product of systolic blood pressure and heart rate (an estimate of myocardial oxygen demand) in older caffeine nonusers, but this effect was absent in older caffeine users (p less than 0.01). Cardiovascular effects of caffeine could not be related temporally to changes in plasma epinephrine, which were greater in caffeine nonusers and younger subjects, or to plasma norepinephrine, renin activity or vasopressin, which did not change. Thus, age accentuates and moderate prior caffeine use attenuates the cardiovascular effects of oral caffeine; these effects are not mediated solely through the sympathoadrenal system.

Adrenal Medulla↗
PubMed1979

Characterization of a UGA-suppressing serine tRNA from Schizosaccharomyces pombe with the help of a new in vitro assay system for eukaryotic suppressor tRNAs.

Two different allele-specific suppressor mutants of the fission yeast Schizosaccharomyces pombe produce opal (UGA) suppressor tRNAs. This was shown by the use of a new in vitro assay for eukaryotic nonsense suppression: a wheat germ extract is programmed with rabbit globin mRNAs and the readthrough products are studied. alpha-Globin is elongated upon addition of ochre (UAA) suppressor tRNAs, whereas beta-globin yields a readthrough product with opal suppressor tRNAs. This simple and very sensitive assay allowed the purification of the opal suppressor tRNA from S. pombe strain sup3-e. The pure tRNA can be aminoacylated with serine; thus, we conclude that this suppressor tRNA inserts serine in response to the UGA termination codon of pure rabbit beta-globin mRNA.

Alleles↗
PubMed1979

An improved rabbit ear model for assessing comedogenic substances.

A simplified comedogenic assay is described in which test materials are applied for 2 weeks to the ears of rabbits just external to the ear canal. Excised tissue is thus immersed in water at 60 degrees C for 2 min, yielding a sheet of epidermis with microcomedones attached. The magnitude of follicular hyperkeratosis is extracted with the stereomicroscope. Sixteen materials were evaluated by the new and old model which required histological sectioning. Agreement was excellent.

Acne Vulgaris↗