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Biomedical subjects

S Wong

Publications and source records attributed to S Wong.

At least 199 records · Page 11Linked to original sources
PubMed1991

Incidence of bacteremia in transesophageal echocardiography: a prospective study of 140 consecutive patients.

The incidence of bacteremia related to transesophageal echocardiography was studied in 140 consecutive patients (71 women and 69 men with a mean age of 53.7 +/- 15 years). Thirty-four patients had one or more prosthetic heart valves. Blood cultures were obtained from each patient through separate venipuncture sites immediately before and after transesophageal echocardiography. An additional late blood culture was obtained in 114 patients 1 h later. The skin was cleaned with povidone-iodine and venipunctures were performed with separate butterfly needles with use of sterile gloves and drapes. Blood samples were drawn into separate syringes, transferred to aerobic and anaerobic culture bottles and processed with use of a semiautomated system. The overall incidence of blood cultures positive for bacteremia was 2% (8 of 394 bottles) and all positive cultures grew in a single blood culture bottle. Positive cultures occurred in 4 (1.4%) of 280 bottles before the procedure, in 2 (0.7%) of 280 bottles immediately after the procedure and in 2 (0.9%) of 228 late (1-h) blood culture bottles. Bacterial isolates were coagulase-negative staphylococci (n = 5), Propionibacterium (n = 2) and Moraxella (n = 1). All were considered contaminants. Mean endoscopic time in these patients was not significantly different from that in the other patients. Follow-up of patients with a blood culture positive for bacteremia revealed no clinical evidence of systemic infection. It is concluded that 1) the incidence of bacteremia related to transesophageal echocardiography is very low, and 2) the incidence of blood cultures positive for bacteremia after transesophageal echocardiography is indistinguishable from the anticipated contamination rate.

Adult↗
PubMed1991

Susceptibility to type I diabetes in women is associated with the CD3 epsilon locus on chromosome 11.

Type I diabetes is associated with the DQ loci of the MHC and to a lesser extent with the T cell antigen receptor (TcR) beta chain genes. The non-obese diabetic (NOD) mouse is an animal model of human diabetes, in which up to 90% of female mice develop overt insulin-dependent diabetes. Genetic studies in the NOD mouse suggest that there are at least three diabetogenic genes; one that maps to the MHC, another that may map to the mouse Thy-I locus, and a third that has still to be identified. We have investigated loci in the vicinity of the human Thy-I locus on chromosome 11q23 and report here the results of restriction fragment length polymorphism (RFLP) analysis of the CD3 epsilon locus of 168 Caucasoid patients with type I diabetes. While no association was found between this locus and type I diabetes, a significant difference in the frequency of the CD3 epsilon 8-kb allele was found between male and female patients (0.268 versus 0.430; P less than 0.0025, Pc = 0.02) and between female patients and healthy female controls (0.430 versus 0.267; P less than 0.015). These results suggest that a gene residing on chromosome 11q23 may confer susceptibility to type I diabetes in women.

Adult↗
PubMed1991

Pseudomonas pseudomallei resistance to beta-lactam antibiotics due to alterations in the chromosomally encoded beta-lactamase.

Pseudomonas pseudomallei, the causative agent of melioidosis, is generally susceptible to some of the newer extended-spectrum cephalosporins or to combinations of a beta-lactam and clavulanic acid, a beta-lactamase inhibitor. Resistance to these agents may, however, emerge during treatment. We report on alterations in the chromosomal beta-lactamase associated with the development of resistance. Three resistance patterns resulted from three different mechanisms in the strains investigated. Derepression of the chromosomal enzyme resulted in a general increase in the MICs of all of the beta-lactams tested. The second mechanism observed was an insensitivity to inhibition of the beta-lactamase by clavulanic acid. In this case, the level of susceptibility to beta-lactams as independent entities remained unchanged. The final "resistance" pattern occurred in a patient treated with ceftazidime and resulted in a beta-lactamase that was capable of hydrolyzing this antibiotic at detectable levels, but with reduced efficacy against other beta-lactams. The net result was a strain that was generally susceptible to all of the beta-lactams tested except ceftazidime. In all cases, the level of susceptibility to antibiotics other than beta-lactams remained unchanged. Such variability found within one genus over a relatively short time course suggests that treatment of infections caused by this organism should be carefully monitored to detect susceptibility alterations to the chosen therapy.

Anti-Bacterial Agents↗
PubMed1991

Efficacy of ketotifen in corticosteroid-dependent idiopathic anaphylaxis.

To assess the potential benefit of ketotifen in the treatment of patients with corticosteroid-dependent idiopathic anaphylaxis, ketotifen was administered in an open trial to nine patients with idiopathic anaphylaxis who required maintenance prednisone for control of their disease. A double-blind trial was not done for reasons of patient safety. After a period of management with prednisone and establishment of the minimal dose of prednisone that controlled idiopathic anaphylaxis, ketotifen was initiated and cautious reduction of prednisone was attempted. The prednisone requirement was not altered in two patients, but prednisone was either substantially reduced or terminated in seven patients. Of these seven, three patients developed recurrent symptoms of idiopathic anaphylaxis after tapering and discontinuation of ketotifen, and ketotifen had to be resumed. The statistical analysis of prednisone reduction was highly significant (P less than .004) and we conclude ketotifen was of significant benefit in seven of nine patients with corticosteroid-dependent idiopathic anaphylaxis.

Adult↗
PubMed1990

Porphyrin photosensitivity in cell lines expressing a heat-resistant phenotype.

In vitro sensitivity to porphyrin-mediated photodynamic therapy (PDT) has been examined in cell lines resistant to hyperthermia. Parental (HA-1) and heat-resistant (3012) Chinese hamster fibroblasts as well as parental (RIF-1) and temperature-resistant (TR-4, TR-5, and TR-10) mouse radiation-induced fibrosarcoma cells were evaluated for thermal and PDT sensitivity. Quantitative survival curves were generated, and porphyrin uptake properties were obtained for all cell lines. Significant resistance to hyperthermia (45 degrees C for varying exposure periods) was documented for the 3012 and temperature-resistant RIF cell strains when compared with the parent lines. Normal and heat-resistant clones, however, exhibited comparable levels of porphyrin uptake and photosensitivity. Our results indicate that cross-resistance between hyperthermia and PDT is not observed and that members of the Mr 70,000 heat shock protein family (which are elevated in the thermal-resistant cells and which may be associated with the heat-resistant phenotype) do not play a significant role in modulating PDT sensitivity. Mechanisms of in vitro cytotoxicity appear to be different for PDT and hyperthermia even though possible subcellular targets (such as the plasma membrane) and types of damage (protein denaturation) may be similar for the two modalities.

Animals↗
PubMed1990

The use of alternative therapies by Auckland general practitioners.

A survey of Auckland general practitioners was undertaken to explore their use of, and attitudes to, alternative medicines. Three hundred and seventy randomly selected doctors, from a total of about 700 doctors practising in Auckland, were posted questionnaires. Of 249 respondents, 75 (30%) practised one or more forms of alternative medicine. Acupuncture was the therapy most commonly used. Musculoskeletal disorders and chronic pain syndromes were the most frequently treated conditions. A total of 171 (68.7%) respondents referred patients to one or more forms of alternative treatment, and only 56 (32.7%) of these felt it necessary that the person referred to be medically qualified. Younger doctors were more inclined to refer and the most commonly cited reason for referral was failure of conventional medicine.

Acupuncture Therapy↗
PubMed1990

Idiopathic anaphylaxis. A clinical summary of 175 patients.

One hundred seventy-five patients with idiopathic anaphylaxis, treated by the same team of physicians, were retrospectively evaluated. The diagnosis of idiopathic anaphylaxis was made only after a careful evaluation had failed to identify an allergen or underlying disease. Before our care of these patients, there were a total of 76 hospital admissions, including 21 intensive care unit admissions and 291 emergency department visits. Prophylactic treatment with maintenance antihistamines and prednisone was appropriate for frequent episodes, and short-term treatment was given for infrequent episodes. No fatalities were reported from idiopathic anaphylaxis in the 124 patients who were available for follow-up. With the appropriate treatment, remissions can be induced in a substantial number of patients. Significant reductions in the frequency of emergency department visits and hospitalizations have been shown, which, in turn, are accompanied by decreases in overall medical costs. In this disease, the period before treatment serves as a control period for comparison after therapy.

Adolescent↗
PubMed1990

Effects of an experimental program on post-hospital adjustment of early discharged patients.

This paper reports the results of a study evaluating the effects of an experimental program on post-hospital adjustment of early discharged patients after total hip arthroplasties. This experimental program consisted of patient teaching by means of a pamphlet and videotape, and regular home visits by a community health nurse. A significant difference was found between the experimental and control patients in perceived preparedness for discharge and post-hospital exercise compliance. The early discharged experimental patients demonstrated post-hospital objective and subjective functional capabilities equal to those of the control patients. This study is seen to have implications for nursing service and nursing education.

Activities of Daily Living↗
PubMed1990

Malignant idiopathic anaphylaxis.

A patient with idiopathic anaphylaxis (IA), classified as generalized IA with frequent episodes, had original episodes in 1985 and has been managed and studied by the authors since 1987. Although her episodes of IA appear to have been controlled by prednisone, progressively larger doses of prednisone have been required. The patient was classified as a patient with corticosteroid-dependent IA, a subset of patients with IA in whom a remission cannot be induced with prednisone and in whom prednisone cannot be stopped. A trial of ketotifen is in progress without definitive effect on prednisone requirement. Because this corticosteroid-dependent patient with IA, which is potentially fatal, cannot be managed on less than 90 mg of alternate-day prednisone, we propose the term malignant IA to categorize such severe cases of IA.

Acute Disease↗
PubMed1990

Influence of sulphate ions on the structure of AA amyloid fibrils.

To explore the possible interaction of sulphated GAG with AA amyloid peptides, human AA amyloid fibrils were exposed to buffers containing various salts, and the accessibility of free amino groups on the peptides to reductive methylation was examined. Sodium chloride had little effect except at concentrations of 1 M, where it reduced the accessibility of AA peptides to labelling. In contrast 70 mM Na2SO4 led to a significant increase in peptide accessibility to labelling. The results suggest that, at least in part, GAG interact with AA peptides through their sulphate moieties.

Chemical Phenomena↗
PubMed1990

Characterization of platelet-activating factor receptors in porcine platelets.

Despite a large number of studies describing the properties and effects of platelet-activating factor (PAF), little is known about its receptor structure. The characterization of the PAF receptor from additional cell types and species is important for the design of strategies to purify and characterize the receptor molecule. Porcine platelets were shown to bind PAF with characteristics similar to several other species, based on receptor number, affinity, and the activity of PAF antagonists. We found that the affinity for binding was higher in porcine than in rabbit platelets (Kd = 0.68 +/- 0.13 nM for rabbit and 0.29 +/- 0.10 nM for porcine). Porcine platelets have approximately 281 +/- 158 receptors per cell compared with 689 +/- 229 receptors in rabbit platelets. Rabbit platelets respond to concentrations of PAF that are approximately 10(5)-fold lower than those required for aggregation of porcine platelets, but this difference is probably not due to the differences in receptor number alone. When binding was compared between purified membranes from these two cell types, porcine platelets had 20-fold fewer receptors per milligram of membrane protein, but this difference may have been due to an artifact of the membrane preparation procedure. Binding of PAF was severely hindered at cold temperatures. It was undetectable in whole cells on ice and greatly reduced with purified membranes. This study is the first to characterize PAF receptors in porcine platelets, which represent a potentially useful source of receptor for further biochemical characterization.

Animals↗
PubMed1990

Nearly fatal idiopathic anaphylactic reaction resulting in cardiovascular collapse and myocardial infarction.

We report a case of nearly fatal cardiovascular collapse attributable to an idiopathic anaphylactic reaction in a 76-year-old man. The event began with gastrointestinal symptoms of abdominal cramps, diarrhea, nausea, and vomiting as manifestations of IA. The patient subsequently progressed to develop urticaria, flushing, cardiovascular symptoms of chest pain, hypotension, and eventually cardiovascular collapse and myocardial infarction over a five-hour interval. This case emphasizes that the potential for life-threatening cardiovascular events from IA exists in patients without previously defined cardiac risk factors.

Aged↗
PubMed1990

Primary care needs of Cambodian refugees.

Cambodian refugees who endured the Pol Pot regime experienced a horrendous assault on their physical and mental health. The complaints and diagnoses of 168 Cambodian refugees who presented to a family medicine primary care clinic between 1985 and 1987 were examined. Fourteen of these patients were visited in their homes to obtain in-depth perspectives of their health beliefs and needs. The results support the growing awareness that Cambodian refugees require sensitive and sophisticated approaches to dealing with widespread emotional and physical dysfunction.

Adolescent↗