PubMed Health⌕ Search

Biomedical subjects

L Emtestam

Publications and source records attributed to L Emtestam.

At least 37 records · Page 2Linked to original sources
PubMed1996

An electrical impedance technique for assessment of wheals.

In previous studies of the electrical impedance of the skin, we introduced a set of physical indices which could be used to distinguish between the cutaneous effects produced by different irritants and allergic contact reactions. In this study, wheals were induced in 10 allergic patients by performing prick tests on the forearm with the relevant allergen and histamine, respectively. Normal skin was used for control. The wheals were evaluated by visual scoring, laser Doppler, and electrical impedance. As expected, there was a close agreement between the visual and laser Doppler readings. Compared to the controls, there were significant changes in the electrical impedance of the wheals, especially in the index related to the phase angle. The changes in the indices were found to follow a particular pattern, which diverged from those obtained in contact skin reactions of both allergic and irritant type. Our results indicate that, by the application of the impedance technique, it will be possible to characterize objectively and quantify the wheal reaction. The results also suggest that cutaneous reactions of completely different causes, such as allergic skin reactions of the late and immediate type, and irritant contact reactions, may be distinguished on the basis of their effects on the electrical impedance of the skin.

Adolescent↗
PubMed1996

On T-cell recognition of nickel as a hapten.

T-cells recognize antigens as peptides associated with self-molecules encoded by genes of the HLA region. In patients with contact allergy to nickel, T-cells that are specific for non-peptide haptens have been described. Previously, we have isolated HLA class II-restricted nickel-specific T-cell clones from patients with nickel sensitivity. In this paper, data on the fine specificity of a nickel-specific HLA-DR4-restricted clone have been reevaluated. Genomic tissue typing employing polymerase chain reaction and sequence-specific primers were used. Nickel was presented to the T-cell clone by all three subtypes of HLA-DR4 included in our panel. Two different DRB4*0404-positive cells presented nickel, whereas only 3 of the 7 DRB1*0401-positive and one of the 3 DRB1*0408-positive cells restimulated the T-cell clone. These findings are compatible with the notion that nickel interacts with endogenous peptides in the antigen-presenting groove of the HLA molecule, thereby changing these peptides' antigenicity rather than their ability to bind to the HLA molecule. Variations of the endogenous peptide in the antigen-presenting groove as well as differences of the HLA molecules give the DR4 specificity of the nickel-specific clone MCE2.

Antigen Presentation↗
PubMed1996

Multiple basal cell carcinomas: no association with HLA-DRB, HLA-DQA1 or HLA-DQB1 in Swedish patients.

Many diseases with autoimmune features are associated with alleles of the human leucocyte antigen (HLA). However, few if any malignant disorders have reproducibly been shown to be HLA-associated. In three independent studies, using serological tissue typing techniques, an increase of the HLA class II specificity DR1 has been found in patients with multiple basal cell carcinomas. These observations prompted us to determine the frequencies of DRB1, DQA1, and DQB1 alleles by high-resolution genomic tissue-typing methods, including subdivision of the serological DR1 specificity in the four sequence-defined alleles, DRB1*0101 to DRB1*0104, in 50 unrelated Swedish patients with a history of four or more basal cell carcinomas and 250 healthy controls. The frequency of DR1 was the same in patients and controls (18%). All DR1-positive patients and controls carried the DQA1*0101 and DQB1*0501 alleles. Six of the nine DR1-positive patients and controls carried the DQA1*0101 and DQB1*0501 allels. Six of the nine DR1-positive patients were DRB1*0101-positive, one DRB1*0102 and two carried the DRB1*0103 allele. This distribution of DRB1*01 alleles did not differ from the one found in the controls. We conclude that genetic factors associated with the HLA class II region do not contribute significantly to the aetiology of multiple basal cell carcinomas.

Adult↗
PubMed1996

Correlation of impedance response patterns to histological findings in irritant skin reactions induced by various surfactants.

We have explored the use of measurements of electrical impedance to discriminate between the effects of different irritant substances upon the skin, and have studied the relationships between impedance and histopathological change. Three compounds with different chemical profiles were tested on volunteers: sodium lauryl sulphate, benzalkonium chloride and nonanoic acid. The concentrations selected were such that each irritant produced responses of a similar order, as judged by visual scores. The magnitude and phase of electrical impedance were measured and, for comparison, also the transepidermal water loss. Four physically distinct aspects (indices) were devised from the impedance data, and the values obtained were statistically analysed. The three irritants produced different effects, giving distinctive impedance patterns. These were also found to be reflected by three different types of histopathological skin response. Our results suggest that the indices can be used to classify irritant contact reactions, which it is difficult or impossible to achieve by other non-invasive techniques.

Adult↗
PubMed1996

Mucocutaneous manifestations in 22 consecutive cases of primary HIV-1 infection.

Twenty-two consecutive patients presenting with symptomatic human immunodeficiency virus 1 (HIV-1) seroconversion were studied. Most of the patients had a glandular fever-like illness. All patients had fever and pharyngitis, and eight of them also suffered from ulcers of the oral, genital or anal mucosa. Uniform skin eruptions were observed in 17 of the 22 patients. The exanthem consisted of varying numbers of macular or maculopapular lesions that were oval or rounded in shape, ranging from a few millimetres to 1 cm in diameter. The lesions were distributed on the upper thorax in all cases, and were particularly profuse in the collar region. The face, forehead and scalp were involved in most cases, but the eruption was sparse or absent at the periphery of the extremities. In the majority of patients, the exanthem appeared after 2 or 3 days of fever. The exanthem developed during the first day, persisted for 5-8 days, and then cleared concurrently with the general recovery of the patients. Histopathological studies of skin punch biopsy specimens from four patients showed a sparse lymphocytic cell infiltrate distributed around vessels of the dermal superficial plexus. The infiltrates predominantly consisted of equally represented T-helper/inducer and T-suppressor/cytotoxic cells. A vacuolar aberration of basal layer cells was found in two of the four cases studied histologically. The microscopic findings correspond to the histopathological patterns seen in toxicodermia and in the interface dermatitis of morbilliform viral exanthems. The exanthem is a frequent and characteristic sign of primary HIV infection, which is further indicated if mucosal ulcers are present.

Adolescent↗
PubMed1996

Successful treatment for acrodermatitis continua of Hallopeau using topical calcipotriol.

We report a 71-year-old woman who had severe inflammatory acrodermatitis continua of Hallopeau. The administration of local remedies, soft X-rays and a number of systemic treatments resulted only in transient and incomplete resolution of the lesions. The pustules, increased skin fragility, tender oedema and erythema were successfully controlled by the local administration of calcipotriol.

Acrodermatitis↗
PubMed1995

Photochemotherapy of oral lichen planus. A controlled study.

Photochemotherapy with 8-methoxypsoralen and long-wave ultraviolet light (PUVA) has become a useful alternative in dermatologic therapy. PUVA therapy has been successfully used in the treatment of severe psoriasis and cutaneous lichen planus. The aim of this investigation was to use PUVA in the treatment of oral lichen planus (OLP). Eighteen patients with long-standing, bilateral, and severe OLP of the buccal mucosa participated in the investigation. A dose of 0.6 mg/kg 8-methoxypsoralen was administered orally 2 hours before long-wave ultraviolet light irradiation was done. The patients were randomly assigned to treatment of the left or right side of the buccal mucosa. The irradiation therapy was given 12 times at intervals of 2 to 3 days, and the patients received a total average dosage of 16.5 J/cm2. The results showed that 13 treated sites compared with six control sites responded significantly favorable to PUVA therapy. Two patients dropped out because of side effects that were similar to those seen after whole-body irradiation PUVA treatment. The follow up times was 12 months. The conclusion of this study is that PUVA seems to be effective in the treatment of OLP and should be considered in severe cases of OLP.

Adult↗
PubMed1995

Electrical impedance measured to five skin depths in mild irritant dermatitis induced by sodium lauryl sulphate.

The non-invasive electrical impedance technique used in this study reflects structural changes in a tissue, and provides an estimate of the level of oedema by a simple impedance index. Sodium lauryl sulphate (SLS), dissolved in water at concentrations of 0.1, 0.5 and 2.0%, was applied for 24 h in 12 mm Finn chambers on both volar forearms of 12 healthy volunteers. An unoccluded area was used as a reference site. Readings from all sites were taken before the application of the irritant, and 24 h after its removal. After the last reading, a 3-mm punch biopsy was taken from each test site for histological examination. The results obtained from electrical impedance measurements at five different skin depths were correlated with those obtained from histological examination, visual scoring and transepidermal water loss (TEWL). For all of the methods used the responses were proportional to the concentration of the irritant. Statistically significant changes of electrical impedance were found for all depths and concentrations, except for 0.1% SLS at the most superficial depth. The histological changes were focused in the epidermis, and mainly consisted of oedema. Alterations in the thickness of the epidermis due to oedema were used as a quantitative parameter for correlation with the assessment of irritation using the electrical impedance technique. For the detection of irritant reactions, TEWL and electrical impedance are more sensitive than visual scoring, and selection of the optimum depth penetration further increases the sensitivity of the electrical impedance measurement.

Adult↗
PubMed1995

Electrical impedance for estimation of irritation in oral mucosa and skin.

Our aim is to establish an objective, easy-to-use technique to evaluate tissue irritation in vivo using non-invasive electrical impedance measurements. Such a technique would facilitate testing the biocompatibility of various materials, and also in quantifying skin diseases and other processes involving structural changes. It has been found that irritation of the oral mucosa not clinically or histologically discernible could be detected with a simple device based on electrical impedance techniques. Originally, the key problem was to focus the probing electrical field in order to minimize artefacts emanating from tissue layers of no interest. The device was then refined and applied to skin testing. It was found that irritation effects far below the limit of the commonly used visual readings could be detected. In this case, it is desirable to exclude from the measurement tissue layers with no diagnostic information, or at least reduce their influence. In this paper, the essential steps of the development of a multi-frequency depth selective device are reviewed.

Artifacts↗
PubMed1994

Electrical impedance compared with other non-invasive bioengineering techniques and visual scoring for detection of irritation in human skin.

A new, non-invasive device, which enables local measurements of electrical impedance to a controlled depth, has been used to evaluate the degree of irritation in human skin. The results have been compared with those obtained using other non-invasive techniques, i.e. with transepidermal water loss (TEWL), electrical capacitance moist measurement (ECM), laser-Doppler flowmetry (LDF), and visual scoring. Sodium lauryl sulphate solutions (0.1-5.0%), and a blank, were applied in Finn Chambers for 24 h on the volar forearm of 10 healthy volunteers. Values were recorded before application of the test chambers, and at 1 h, 24 h, 1 week and 2 weeks after removal. Thus, both the degree of initial damage and the healing process were monitored. There was close agreement among values obtained using electrical impedance, TEWL and visual readings. Results obtained using ECM and LDF were not consistent with the other three methods. In evaluating irritation of the skin, the practical situation may influence the choice of bioengineering tools. In most circumstances, a combination of methods would be preferable.

Adult↗
PubMed1994

Surgical treatment of chronic hidradenitis suppurativa: CO2 laser stripping-secondary intention technique.

The objective of our study was to evaluate a surgical method of management of patients with hidradenitis suppurativa (HS), using a CO2 laser technique for stepwise horizontal vaporization and peroperative monitoring of the removal of diseased tissue. Twenty-four patients were selected for treatment, 21 women and three men, who had suffered from HS for a mean of 13 years (range 1-28 years) and experienced more than three recurrences of suppurating lesions during the year prior to entering the study. The mean follow-up time after CO2 laser surgery was 27 months (range 15-47 months), with clinical follow-up once or twice a week during the wound-healing period, and then at intervals of 1-3 months to evaluate recurrences and assess the end result. The patients' healing time was approximately 4 weeks (range 3-5 weeks). During the follow-up period two patients had recurrences in the treated areas. Twenty-two patients had no recurrences in the treated areas, but in four cases de novo suppurating lesions appeared 5-10 cm beyond the initial sites of surgery. Ten patients had exacerbations of HS lesion(s) in a region other than the treated site. Eight patients did not have any recurrences. Post-surgery results were satisfactory both cosmetically and with regard to quality of life. The CO2 laser stripping-secondary intention technique is a rapid, efficient, and economical method for the treatment of HS. It allows simple treatment of early lesions which would otherwise have been treated using less effective local conservative remedies.

Adult↗
PubMed1993

HLA-DR, -DQ and -DP alleles in nickel, chromium, and/or cobalt-sensitive individuals: genomic analysis based on restriction fragment length polymorphisms.

The increased concordance rate of nickel sensitivity in monozygotic compared to dizygotic twins indicates a genetic causal component. We have previously described an association in nickel-sensitive subjects with an HLA-DQA restriction fragment length polymorphism (RFLP) (4.5-kb TaqI band, DQA1*0501). The purpose of the present study was to investigate if our previous finding could be confirmed in an independent study, and also to investigate the distribution of HLA class II alleles in chromium- and cobalt-sensitive individuals. Using TaqI- or MspI-digested DNA and DQA, DQB, DRB, DPA and DPB cDNA probes alleles were defined by RFLP analysis. The association with the DQA1*0501 allele was not confirmed in the new group of 37 nickel-sensitive subjects (compared to 150 new controls), nor when the two groups of patients were combined. The distribution of HLA class II alleles and DR-DQ haplotypes were similar in the pooled group of 70 nickel-sensitive subjects and the combined control groups (n = 250). No significant changes in the distribution of HLA class II allele among the chromium- (n = 26) and/or cobalt- (n = 38) sensitive individuals were found. Our results indicate that it is unlikely that the tendency to develop metal sensitivity is associated with alleles of the HLA class II region.

Alleles↗
PubMed1993

Electrical impedance index in human skin: measurements after occlusion, in 5 anatomical regions and in mild irritant contact dermatitis.

The electrical impedance in 23 healthy volunteers at 2-6 different skin sites was measured with a new impedance device, which makes possible non-invasive local measurements to a controlled depth. In 11 subjects, the test sites were occluded for 24 h using empty Finn Chambers and chambers with water, physiological saline, a paper disc or 0.002% sodium lauryl sulfate (SLS). In the normal skin of 10 subjects, the electrical impedance was measured from 5 different body areas for 5 consecutive days. In 3 subjects, daily measurements for 1 month were done, both from normal skin and from skin following the application of 2% SLS. The results show that the irritation index based on electrical skin impedance gives little day-to-day variation at one and the same test site, in comparison to the variations between different test sites on the same subject and the interindividual variations observed. Significant differences in impedance values between different anatomical regions of normal skin were found. Occlusion does not affect readings taken 24 h or later after removal, but increases variance for readings taken 1 h after removal. Effects on the skin of mild irritation and its recovery phase are easily monitored with the new device. Technology based on electrical impedance, in its newly presented form, with the advantages of improved geometrical definition and depth control, can be used as an objective tool to measure skin irritation. For detection of subclinical irritant contact dermatitis, repeated readings taken over several days may be needed.

Adult↗
PubMed1993

Photodynamic properties of Sn-protoporphyrin: clinical investigations and phototesting in human subjects.

Pure synthetic metalloporphyrins have been developed for experimental and clinical use as inhibitors of heme oxygenase, the rate limiting enzyme in the catabolism of heme to bilirubin. Tin (Sn)-protoporphyrin is one such compound, which potently suppresses bilirubin production and thus jaundice in animals and man. We have previously reported that this metalloporphyrin in conjunction with UVA might be useful as a treatment for psoriasis. To assess the photodynamic properties of Sn-protoporphyrin, 31 subjects were investigated with regard to photosensitivity. In all subjects, phototesting using UVB, UVA, and visible light as well as photopatch testing was performed. Our investigations revealed that 16 of the 31 individuals treated with Sn-protoporphyrin developed a mild photosensitivity, mainly erythema of the hands and face, and in some cases a mild conjunctivitis. The duration of this sensitivity, which in no case caused discomfort, was dose-dependent and ranged from several weeks to 1-3 months. After administration of Sn-protoporphyrin, lower thresholds were found for both UVA and visible light, but the sensitivity for UVB was normal and photopatch tests were negative. In summary, the photosensitivity observed during Sn-protoporphyrin administration was of limited duration and magnitude and did not occur in all subjects. Thus, the combination of photoactive synthetic metalloporphyrins and artificial light might prove to be useful as a regimen for the treatment of skin disease.

Adult↗
PubMed1992

Electrical impedance applied to non-invasive detection of irritation in skin.

Healthy volunteers were subjected to irritation by sodium lauryl sulphate at concentrations in the range 0.002% to 5.0% applied in Finn Chambers for 24 h. Test sites were visually assessed 1 h and 24 h after cessation of exposure. At the same times electrical impedance was measured with a new impedance device which allows non-invasive local measurements to a controlled depth. Close agreement between concentration and an irritation index calculated from electrical impedance parameters was found over the whole concentration range for most test persons. At concentrations below 0.2%, visual scores were zero. These results suggest that electrical impedance can be used as an objective tool to record irritation, and further that electrical impedance might be a more sensitive method than the commonly used visual readings.

Adolescent↗
PubMed1990

Studies with the haeme oxygenase inhibitor Sn-protoporphyrin in patients with primary biliary cirrhosis and idiopathic haemochromatosis.

Sn(tin4+)-protoporphyrin, a potent competitive inhibitor of haeme oxygenase, the rate limiting enzyme in the degradation of haeme to bile pigments, was given intravenously to six patients with primary biliary cirrhosis and to four patients with idiopathic haemochromatosis. Serum bilirubin concentrations decreased in all patients after administration of 1-2 mumol/kg body weight of the metalloporphyrin, given in two doses eight to 24 hours apart. This reduction lasted approximately four to five days after injection of the compound. Excretion of endogenous haeme in bile increased (mean increase approximately two to threefold) in parallel with the decrease in serum bilirubin concentrations in both patient groups, and the highest biliary haeme concentrations were found during the first 48 hours after treatment. Sn-protoporphyrin was cleared rapidly from plasma with a half-life of 3.4 hours. Biliary bilirubin concentrations decreased (mean decrease, 49%) in the haemochromatosis patients after Sn-protoporphyrin administration. No decrease in biliary bilirubin concentrations could be detected in the primary biliary cirrhosis patients under the same conditions. Thus, Sn-protoporphyrin treatment resulted in a decrease in serum bilirubin concentrations and an increase in biliary haeme excretion in patients with haemochromatosis and primary biliary cirrhosis, as has previously been shown in normal subjects. The results indicate that the synthetic haeme analogue inhibits haeme oxidation activity in the two patient groups studied, as it does in normal people and in experimental animals. The lack of effect of Sn-protoporphyrin on biliary bilirubin excretion in primary biliary cirrhosis may be related to a differently affected hepatic clearance system or to a different distribution of tissue bilirubin pools in this condition.

Adult↗
PubMed1989

Tin-protoporphyrin and long wave length ultraviolet light in treatment of psoriasis.

To assess the effects of tin (Sn)-protoporphyrin (a synthetic haem analogue) in conjunction with long wave length ultraviolet light (UVA) radiation in psoriasis 10 patients, 9 of whom were substantially or completely unresponsive to other forms of therapy, received 2.0 mumol/kg bodyweight of Sn-protoporphyrin for 1 day followed by UVA light treatment for 21 days. The average starting UVA dose was 5.6 (SD 2.0) J/cm2, and the average cumulative UVA dose was 98.3 (35.1) J/cm2. Severity of psoriatic plaques, scored clinically on a scale of 0-3 for erythema, scaling, and induration, fell from a mean score of 7.9 at the start of the study to 3.6 at the end. Psoriatic lesions were improved in all patients and the effect was striking in some. The responses lasted throughout the three weeks of the study and no deleterious side-effects of the treatment were noted. Clinical follow-up for three months showed no rebound in disease activity. Sn-protoporphyrin with conventional UVA light may be useful in the treatment of psoriasis.

Adult↗