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Biomedical subjects

J T Lear

Publications and source records attributed to J T Lear.

At least 55 records · Page 3Linked to original sources
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

Truncal site and detoxifying enzyme polymorphisms significantly reduce time to presentation of further primary cutaneous basal cell carcinoma.

Basal cell carcinoma (BCC) is the commonest cancer in Caucasians. Its incidence is rising and many patients develop multiple primary tumours at separate sites. Factors determining time between first primary tumour presentation and the next new primary lesion are unclear. We used Cox's proportional hazards model to study, in 856 Caucasians, the influence of tumour site, individual characteristics and polymorphism in glutathione S-transferase (GSTM1, GSTT1) and cytochrome P450 (CYP2D6, CYP1A1) loci on time to next primary tumour presentation. More than one tumour at first presentation (P <0.0001, hazard ratio 2.72) and GSTT1 null (P = 0.028, hazard ratio 1.74) were associated with decreased time to next primary tumour presentation. Significant two-factor interactions, corrected for number of tumours at presentation, were identified between a truncal tumour at first presentation and each of male gender, GSTM1 null and CYP2D6 EM (P <0.003, hazard ratios 3.09-3.82). In each of these cases, all patients with the risk combination demonstrated further separate tumours within 5 years of first presentation. Thus, patients with a truncal tumour at first presentation, especially males and those presenting with more than one lesion have a significantly decreased time to presentation of further tumours and should receive more meticulous follow-up. Polymorphism in GSTM1 and CYP2D6 also influences the rate of new primary tumour accrual giving insights into the link between ultraviolet exposure and multiple tumour development.

Aged↗
PubMed1997

Truncal tumor site is associated with high risk of multiple basal cell carcinoma and is influenced by glutathione S-transferase, GSTT1, and cytochrome P450, CYP1A1 genotypes, and their interaction.

Basal cell carcinoma (BCC) places increasing burdens on clinicians; incidence is rising and patients may develop multiple primary tumors. Although UV exposure is critical, many patients develop tumors at less-exposed sites, such as the trunk, suggesting a genetic predisposition. We previously showed that polymorphism in loci encoding the detoxifying enzymes, glutathione S-transferase (GSTM1, GSTM3, GSTT1) and cytochrome P450 (CYP2D6, CYP1A1) influences susceptibility to BCC. We now describe a case-control approach in 345 patients with BCC that examines the role of these polymorphisms and patient characteristics (age, gender, skin type, hair color, eye color, smoking, occupation) in determining susceptibility to truncal tumors. GST and CYP genotypes were identified using polymerase chain reaction-based methods. Patients with one or more truncal tumors were significantly younger (p = 0.0170) than those with no truncal tumors. Male gender also appeared more common in the truncal tumor group, although this did not achieve significance (p = 0.0925). Patients whose first tumor was truncal had significantly more tumors (p = 0.0297). GSTT1 null (p = 0.0245, odds ratio 2.24) and CYP1A1 Ile/Ile (p = 0.0386, odds ratio 2.86) were associated with truncal site after correction for age and gender. The combination, GSTT1 null and CYP1A1 Ile/Ile, was particularly significant (p = 0.0059, odds ratio = 2.95). These effects were present after correction for tumor numbers. These data show first, patients with truncal tumors constitute a high-risk group for BCC, second, a significant genetic influence on BCC site, and third, a significant interaction between GSTT1 and CYP1A1 genotypes.

Aged↗
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

Neutrophilic dermatoses: pyoderma gangrenosum and Sweet's syndrome.

Pyoderma gangrenosum and Sweet's syndrome are classified as neutrophilic dermatoses as they exhibit intense dermal inflammatory infiltrates composed of neutrophils with little evidence of a primary vasculitis. They share several characteristics and respond to immunosuppressives. Aetiology is felt to represent a manifestation of altered immunologic reactivity. Patients with both conditions concurrently have been described. Diagnosis is based on clinical and histopathological findings. However, clinically the typical forms of the two conditions are quite distinct: pyoderma showing cutaneous ulceration with a purple undermined border and Sweet's syndrome having tender, erythematous, nonulcerated plaques and nodules. Approximately 50% of cases of pyoderma are associated with a specific systemic disorder. These include inflammatory bowel disease, rheumatoid arthritis, non-Hodgkin's lymphoma and myeloproliferative disorders. Many associations with Sweet's syndrome have been described, including acute myeloid leukaemia, myeloma and adenocarcinomas, and haematological malignancy. There is overlap between the two conditions with lesions categorised as Sweet's syndrome being clinically more characteristic of atypical pyoderma and vice versa. We believe that pyoderma and Sweet's syndrome represent a continuum of spectrum of disease. The reason for the clinical differences between the conditions is unclear and merits further investigation but may be explained by varying levels of intensity and extent of the inflammatory process. This review will describe the pathogenesis, clinical features, diagnosis, associations and treatment of the two conditions.

Aged↗
PubMed1997

Basal cell carcinoma.

Basal cell carcinoma is the commonest malignancy in Caucasians with incidence rates of 300 per 100,000 reported in the USA. Rates are increasing at over 10% per year leading to a lifetime risk of 30%. Although mortality is low, the disease is responsible for considerable morbidity and places a substantial burden on health service provision in the UK. Furthermore, lesions may recur and patients often develop multiple tumours giving major implications for treatment and follow-up. Four main types of basal cell carcinoma are seen: nodulo-ulcerative; pigmented; morpheaform and superficial. Diagnosis is by histological evaluation although many tumours have a characteristic clinical appearance. The differential diagnosis is large. Identified risk factors include male gender, skin type 1, red/blonde hair and increasing age. Patients with basal cell carcinoma are more likely to develop malignant melanoma and squamous cell carcinoma but it is still unclear whether there is a link with internal malignancy. The main treatment modalities are surgery and radiotherapy. Each has advantages and disadvantages. The choice of treatment depends on many factors. Principles of treatment include identification of high-risk patients to enable early detection, complete removal of the lesion, and careful follow-up to detect recurrence or new lesions. Approximately 10% of tumours recur, depending on site, size and treatment modality. Metastatic basal cell carcinoma and the association of ultraviolet radiation to basal cell carcinoma risk are reviewed.

Basal Cell Carcinoma↗
PubMed1997

Risk factors for ischaemic heart disease in patients with dermatitis herpetiformis.

For reasons that are unclear, patients with dermatitis herpetiformis (DH) have a lower than expected mortality rate from ischaemic heart disease. We have compared risk factors for ischaemic heart disease (lipids, fibrinogen levels, smoking history and social class) in 29 DH patients and 57 controls matched for age and sex. Patients with DH had significantly lower cholesterol, triglycerides, apolipoprotein B and fibrinogen and higher HDL2; they also smoked less and were of higher social class. The mechanisms underlying these observations merit further investigation. Intestinal abnormalities or gluten-free diet may account for differences in lipid fractions, and the immunomodulatory properties of cigarette smoke may protect against the development of DH.

Aged↗
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↗