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Biomedical subjects

B B Tan

Publications and source records attributed to B B Tan.

At least 19 recordsLinked to original sources
PubMed2001

Interleukin-10 prevents loss of tone of rat skeletal muscle arterioles exposed to endotoxin.

BACKGROUND: The anti-inflammatory cytokine interleukin-10 (IL-10) is known to inhibit the development of septic shock in animal models. This study was conducted to investigate the effect of IL-10 on the loss of vascular tone during exposure to endotoxin. Unlike numerous proinflammatory cytokines, the effects of IL-10 at the level of the microvasculature have not been previously studied. MATERIALS AND METHODS: First-order rat cremasteric arterioles (n = 27) were placed in an isolated vessel preparation and allowed to achieve spontaneous tone. An opened segment of thoracic aorta was then placed upstream from the arteriole in the superfusion line. The resistance arteriole of this in-series model, in contrast to the isolated arteriole alone, demonstrates a significant loss of tone when exposed to endotoxin. Following 1 h of equilibration in the presence or absence of IL-10 (20 ng/ml), the aorta and arteriole were then superfused with 2.5 microg/ml endotoxin or physiologic buffer for 60 min and serial arteriolar diameter measurements were recorded. Group 1 was exposed to endotoxin only, Group 2 was a time control, and Group 3 was pretreated with IL-10 prior to endotoxin exposure, while Group 4 was a control pretreated with IL-10 only. RESULTS: After the 60-min equilibration period there were no differences among the four groups in arteriolar tone. At t = 120 min, the percentage of tone in the control group was 43.6 +/- 3% (mean +/- SEM) and this was not changed by treatment with IL-10 (47.0 +/- 7% tone). Endotoxin alone caused arteriolar tone to fall to 31.4 +/- 3% (P < 0.05). However, endotoxin applied to arterioles pretreated with IL-10 was without effect (47.5 +/- 2%). CONCLUSIONS: Resistance arterioles pretreated with IL-10 maintain vascular tone during endotoxin exposure. We conclude that IL-10 pretreatment prevents loss of vascular tone of isolated arterioles exposed to endotoxin.

Acetylcholine↗
PubMed1998

Mite elimination--clinical effect on eczema.

Allergic reactivity to house-dust mites (HDM) can be detected in patients with atopic eczema by prick and patch test challenge. To determine the clinical relevance of this reactivity, we performed a placebo-controlled, double-blind trial of anti-HDM measures. Active treatment comprised Gortex bags for all the bedding elements, a high-powered vacuum cleaner, and a spray containing benzyl alcohol and tannic acid to kill mites and denature allergens. Placebo treatment was light cotton bags, a cheap vacuum cleaner, and water spray. Forty-eight patients (28 active group) completed the trial, which lasted 6 months. Dust was sampled from the mattress surface and bedroom and living-room carpets before and at monthly intervals after institution of the measures. Dust was weighed and Der p 1 determined by ELISA (ALK). Patients were assessed for area and severity of eczema by a blinded observer. There was a highly significant reduction in bed surface dust - most beds yielded insufficient dust to extract and assay. Carpet Der p 1 levels were reduced to similar minimal levels by both active and placebo treatments (about 250 ng/m2). There were highly significant benefits on the eczema scores, the active treatment being greatly superior to placebo (P< or =0.0006; analysis of covariance). In conclusion, Gortex bed bags were highly effective at containing dust within the bed. This was associated with clinical improvement in most patients with atopic eczema - the biggest improvements were seen in the most severely affected subjects.

Adolescent↗
PubMed1997

Acne fulminans and erythema nodosum during isotretinoin therapy responding to dapsone.

Acne vulgaris is very common, 85% of teenagers being affected at any one time. In most cases, the disease is mild and patients do not present to the dermatologist. Most are instead treated with over-the-counter products and conventional treatment such as peeling agents or topical and systemic antibiotics. Isotretinoin has revolutionized the treatment of severe acne unresponsive to oral antibiotics. Explosive and very severe acne such as pyoderma faciale, acne conglobata and acne fulminans are rare, the features that distinguish acne fulminans from the other conditions being systemic upset with fever, joint pain, malaise and leucocytosis, while there have been two reports of the condition associated with erythema nodosum. The recommended treatment for acne fulminans is a combination of oral steroids and systemic antibiotics, isotretinoin probably not being the treatment of choice. We now report a patient who developed acne fulminans and erythema nodosum within 3 weeks of starting isotretinoin and then responded to dapsone without oral steroids.

Acne Vulgaris↗
PubMed1997

Perioperative collapse: prevalence of latex allergy in patients sensitive to anaesthetic agents.

The evidence in the literature suggests that the prevalence of latex allergy in the general population is approximately 1%. With increasing awareness of transmission of HIV and other infections such as hepatitis B, the use of latex gloves and condoms has escalated in recent years. As cheaper latex gloves of variable and doubtful quality flood the market, health care workers and patients are being increasingly sensitized by these latex products. A retrospective study investigated the prevalence of latex allergy in a cohort of 26 patients who suffered perioperative anaphylactoid reactions. 84% of these patients were hypersensitive to at least 1 anaesthetic-related agent. 7.7% were also allergic to latex (p = 0.028). Atopy is a strong predisposing factor (p = 0.006). An accurate preoperative history of atopy and past reactions to latex will identify most at-risk patients. Prick test and RAST to latex will confirm the latex allergy. Anaesthetists, surgeons, allergists and other health practitioners should be aware of this problem.

Adolescent↗
PubMed1997

Risk factors for basal cell carcinoma in the UK: case-control study in 806 patients.

Basal cell carcinoma (BCC) is the commonest malignant neoplasm in white people. We present a large UK case-control study in which conditional logistic regression analysis of age-matched and gender-matched data sets was used to compare, first, cases with controls (n = 403) and second, patients having multiple BCC with those having a single BCC (n = 278). Eye/hair colour, occupation, skin type, social class, tumour site at presentation and smoking history were assessed. Social class 1/2, skin type 1, red/blonde hair and blue/green eyes were all related to BCC risk, social class most strongly (odds ratio 2.36, P = 0.007). Truncal site at presentation was a risk factor for the development of multiple BCC (odds ratio 4.03, P = 0.002). These data support the view that genetically mediated differences in ultraviolet responsiveness are important in BCC, though the scale of their effect is small. They may be exploitable in primary and secondary prevention as well as giving insights into pathogenesis. In particular, the fact that patients presenting with a truncal tumour are at increased risk of further BCC suggests that intermittent exposure in genetically predisposed individuals may contribute to a cancer susceptibility syndrome.

Basal Cell Carcinoma↗
PubMed1997

Azathioprine in dermatology: a survey of current practice in the U.K.

Azathioprine has an important role in treatment of many inflammatory dermatoses. In view of the current emphasis on evidence-based medicine, we performed a questionnaire-based survey to establish current practice in the use of azathioprine by consultant dermatologists and associate specialists in the U.K. The response rate was 68%. In contrast with the manufacturer's recommendation, our data provide evidence that azathioprine is useful in the treatment of a wide variety of dermatological diseases. However, there is still a need for controlled trials in some conditions. The most common conditions treated were pemphigoid, pemphigus and atopic eczema. In addition, we found that only 13% of dermatologists prescribe azathioprine according to body weight. Most dermatologists felt that azathioprine was well tolerated. No one tested for thiopurine methyltransferase (TPMT) activity, which is thought to be a predictor of severe myelosuppression. The combination of prescribing azathioprine according to body weight and measuring TPMT activity would optimize efficacy and minimize potential severe myelotoxicity.

Azathioprine↗
PubMed1996

Double-blind controlled trial of effect of housedust-mite allergen avoidance on atopic dermatitis.

BACKGROUND: The role of housedust-mite (HDM) allergen (Der p1) in the pathogenesis of atopic dermatitis is controversial. We tested the hypothesis that atopic dermatitis improves if amounts of HDM allergen in the home are reduced. METHODS: Active treatment comprised Goretex bedcovers (placebo, cotton covers), benzyltannate spray (placebo, water), and a high-filtration vacuum cleaner (placebo, a conventional domestic vacuum cleaner). Dust was sampled monthly from the mattress covers and bedroom and living-room carpets. 48 patients (24 adults [mean age 30] and 24 children [mean age 10]) completed the 6-month study. 28 were in the active treatment group and 20 in the placebo group. FINDINGS: The weight of dust collected from Goretex-covered mattresses had fallen by 98% at 1 month (from 386 to 9 mg/m2) with no change thereafter. Placebo covers caused a smaller reduction in dust load (361 to 269 mg/m2); the difference between active and placebo covers at 6 months was highly significant (p = 0.002). Both active and placebo treatments caused significant reductions in Der p1 concentrations in bedroom and living-room carpets and the differences between the treatments were not significant. The severity of eczema decreased in both groups, but the active group showed significantly greater improvements in severity score (difference between mean final scores 4.3 units, p = 0.006) and area affected (difference between mean final areas 10%, p = 0.006) in analysis of covariance with initial mattress dust weights and bedroom carpet Der p1 load as covariates. Reported analysis with final values for the covariates showed that most of the treatment effect was due to the reduction in mattress dust and carpet Der p1. INTERPRETATION: The activity of atopic dermatitis can be greatly reduced by effective HDM avoidance. Methods to identify individuals who will benefit most from such measures are needed.

Adolescent↗
PubMed1996

Transient re-emergence of oil of turpentine allergy in the pottery industry.

Allergy to oil of turpentine has diminished largely due to the use of cheaper substitutes in many occupations. However, 2 particular areas still reliant on real oil of turpentine are those of the perfume industry and ceramic decoration. We report 24 cases of hand dermatitis in pottery workers involved in ceramic decoration, paintresses, liners, gilders, enamellers and a fine china painter, seen in a 6-month period following a change from Portuguese to Indonesian turpentine, of whom 14 were sensitive to Indonesian turpentine, 8 to alpha-pinene, 4 to delta-3-carene and 2 positive to turpentine peroxides. Previous reports suggest that delta-3-carene is the main allergen and reports of sensitivity to alpha-pinene in the absence of sensitivity to turpentine peroxide, in particular to the hydroperoxide of delta-3-carene, are few. Turpentine allergy continues to be a problem in the pottery industry and is more common than allergy to the heavy metals of the colours used in ceramic decoration. alpha-Pinene, an unusual allergen, appears to be the most common in our area. Reversion to Portuguese turpentine seems to have alleviated the problem.

Allergens↗