Search PubMed⌕ Search

Biomedical subjects

A Lahti

Publications and source records attributed to A Lahti.

At least 55 records · Page 3Linked to original sources
PubMed1991

Reduced frequency of nickel allergy upon oral nickel contact at an early age.

From animal studies we know that oral administration of T-dependent antigens before sensitization effectively induces systemic immune unresponsiveness. Such 'oral tolerance' is persistent, dose-dependent, antigen-specific and presumably T suppressor cell-mediated. Oral tolerance induction could be an effective way to prevent undesired T cell-mediated immune functions, such as playing a role in allograft reaction, autoimmune and allergic diseases. In the present study allergic contact hypersensitivity (ACH) to nickel, currently presenting the most frequent contact allergy in man, was chosen to establish the feasibility of oral prevention of undesired T cell-mediated immunity in man. Potentially tolerizing (oral nickel contacts via orthodontic braces) as well as sensitizing (ear piercing) events were studied retrospectively in 2176 patients attending nine European patch test clinics. Patients were interviewed by means of a confidential questionnaire. The results show that ear piercing strongly favoured development of nickel ACH. More importantly, patients having had oral contacts with nickel-releasing appliances (dental braces) at an early age, but only if prior to ear piercing, showed a reduced frequency of nickel hypersensitivity. Frequencies of other hypersensitivities, in particular to fragrance, were not affected. These results support our view that induction of specific systemic immunologic tolerance by timely oral administration of antigens is feasible in man.

Adolescent↗
PubMed1990

Contact allergy to Bronopol.

A total of 8149 patients were patch tested with the preservative Bronopol in 7 European contact clinics. The majority of patients (6507) were investigated in London. Reactivity was low, with a total of 10 irritant (0.12%) and 38 allergic reactions (0.47%). In only 17 cases (0.21%) was the patch test reaction to Bronopol considered to be of current or past clinical relevance. Concomitant sensitization to formaldehyde was present in about 1/3 of patients. Based on these figures, the present sensitization rate to Bronopol in Europe seems to be quite low, which may be related to its less frequent use as a preservative in cosmetics and medicaments in comparison to parabens or isothiazolinones.

Adolescent↗
PubMed1989

Immediate contact reactions to benzoic acid and the sodium salt of pyrrolidone carboxylic acid. Comparison of various skin sites.

Benzoic acid (BA) and the sodium salt of pyrrolidone carboxylic acid (NaPCA) were tested in 13 healthy persons to obtain information about, firstly, the irritant properties of NaPCA and, secondly, the reactivity of various skin sites. BA at 16, 8, and 4 mM pet., and NaPCA at 50, 25, 12.5, and 6.25% in water, were applied to the forehead, cheek, neck and upper back. Erythema reactions were observed visually, and the changes in the skin blood flow were monitored using a laser-Doppler flowmeter. BA at 16 mM increased blood flow on the cheek of 12 test subjects, and on the neck, forehead and upper back of 6 subjects, but 8 and 4 mM BA elicited reactions only on the cheek. NaPCA caused reactions on the upper back of 3 test subjects only, but not on other test sites.

Adult↗
PubMed1989

Daily measurements of salivary progesterone reveal a high rate of anovulation in healthy students.

Daily concentrations of salivary progesterone (P) were measured from 32 women during a complete menstrual cycle. Seventeen of the subjects were university students and 15 were patients of an infertility clinic (a severe male-factor was verified as the cause of infertility in all of them). Commercially available reagents for radio-immunoassay of serum P were modified for salivary measurements, to yield acceptable precision and sensitivity (40 pmol/l). Good correlation (r = 0.93) was found between salivary and serum P concentrations in samples collected simultaneously. The follicular phase levels of salivary P were below 100 pmol/l, and those at the luteal peak were 390 +/- 45 pmol/l (mean +/- SEM, n = 24). From the menstrual salivary P concentration curves we identified the first day of significant elevation above mean follicular levels (T2) and thereafter calculated the cumulative sum of daily P concentrations until 95% of the luteal phase secretion had accumulated (C95). The time needed to reach C95 (designated T95) and logC95 were plotted in coordinates and used as the basis of evaluation of normal menstrual P secretion. The observations were distributed in two groups, one with clearly identifiable T2 and a distinct luteal-phase P (ovulation had occurred) and one with no identifiable T2 and absent luteal-phase P peak (indicative of anovulation). Interestingly, 47% of the student population had an abnormally low menstrual P profile while all the other subjects displayed a clear luteal-phase peak of salivary P. These data provide more evidence for applicability of salivary P measurements for diagnosis of corpus luteam function and highlight the difficulty of selecting representative reference populations in studies on female reproductive endocrinology.

Adult↗
PubMed1989

Start and end of the effects of terfenadine and astemizole on histamine-induced wheals in human skin.

A study was made of effects of two antihistamines, terfenadine (60 mg twice daily) and astemizole (10 mg once daily) on wheals induced by histamine dihydrochloride (10 mg/ml) in the prick test on the upper back of 15 healthy students. The suppressive effects of terfenadine on the histamine wheal appeared earlier (2 h), and disappeared earlier (within 1 day) than those of astemizole (3 days and 28 days, respectively). No difference between the maximal effects of the two drugs was seen.

Adult↗
PubMed1989

Oculomotor abnormalities and their clinical correlates in schizophrenia.

Smooth pursuit eye movements (SPEMs) have been consistently found to be abnormal in the majority of schizophrenic patients. The traditional SPEM measurement technique, however, fails to inform us about the underlying oculomotor deficit in these patients, since it remains a non-specific and a global oculomotor measure. A number of diverse clinical features such as tardive dyskinesia (TD) or negative symptoms correlate with the SPEM abnormality. Other eye movement abnormalities such as fixation difficulties, increased "volitional" saccadic latency and saccadic distractibility in anti-saccade paradigm have also been noted in schizophrenic patients. Still, it remains unclear how these different eye movement measures relate with each other and with the traditional SPEM measure, the presence of which is so widely described in schizophrenia. The advantage of some newer oculomotor paradigms is their functional specificity and the degree to which their biology is known. To further address these issues and to search for clinical correlates of various eye movement abnormalities found in schizophrenia, we have developed a battery of oculomotor measures to be administered to a large number of clinically well described schizophrenic patients and normal controls. The results from a preliminary analysis of a relatively small number of subjects are presented here, thus limiting the scope of possible conclusions. But, these results do indicate that this technique of studying multiple paradigms for oculomotor control in schizophrenia may prove to be fruitful.

Eye Movements↗
PubMed1989

Effect of ultraviolet B on nonimmunologic contact reactions induced by dimethyl sulphoxide, phenol and sodium lauryl sulphate.

The effect of ultraviolet light B (UVB) on immediate and delayed irritant reactions induced by dimethyl sulphoxide (DMSO), phenol, and sodium lauryl sulphate (SLS) was studied in 12 volunteers. One half of the upper back was irradiated with 0.16 J/cm2 of UVB. Patch tests for immediate reactions were performed using dilution series of test substances on the 3rd, 9th and 15th days and for delayed reactions on the 2nd, 8th and 14th days after irradiation both on the UV-exposed and non-exposed areas of the back. The occlusion time was 20 min for immediate reactions and 20 h for delayed ones. Changes in the skin blood flow of the test sites were monitored using laser-Doppler flowmetry, and erythema and edema reactions were observed visually. Both immediate and delayed reactions were caused by DMSO and phenol; SLS elicited only delayed reactions. UVB diminished immediate reactions induced by phenol for at least 15 days after irradiation. Immediate reactions to DMSO were diminished 40 min after application on the UV-exposed area on the 3rd day. UVB diminished the delayed reactions from SLS and DMSO but not reactions induced by phenol.

Adult↗
PubMed1988

Ultraviolet light inhibits nonimmunologic immediate contact reactions to benzoic acid.

The effect of ultraviolet B (UVB) and ultraviolet A (UVA) irradiation on nonimmunologic immediate contact reactions (NIICRs) induced by benzoid acid (BA) was studied in 14 and 13 test subjects, respectively. 10 x 20 cm areas of the back skin were irradiated with 0.08, 0.16, and 0.24 J/cm2 UVB, and with 20 and 60 J/cm2 UVA. Five concentrations of BA were applied to the UV-exposed and nonexposed areas on the 1st, 3rd, 7th, and 21st day after UVB irradiation and on the 1st, 3rd, 7th, and 14th day after UVA irradiation. Forty minutes after BA application, erythema and edema reactions were observed visually, and changes in the skin blood flow were monitored using laser-Doppler flowmetry. The highest dose of UVB significantly inhibited NIICRs for 3 weeks. The lower doses of UVB had a weaker effect. Both doses of UVA diminished blood flow in NIICRs to lower concentrations of BA for 14 days.

Adult↗
PubMed1988

Topical non-steroidal anti-inflammatory drugs inhibit non-immunologic immediate contact reactions.

The effects of 3 topical applications of non-steroidal anti-inflammatory drugs (NSAIDs), diclofenac 1%, naproxene 10% and salicylic acid 5% in gel vehicles, on immediate contact reactions to 500 mM benzoic acid, 500 mM cinnamic aldehyde, 50 mM methyl nicotinate, all in pet., and 14.1 M (100%) dimethyl sulfoxide, were studied in 16 medical students. Erythema and edema reactions were observed visually, and the changes in the skin blood flow were monitored using laser-Doppler flowmetry (LDF). NSAIDs had significant inhibitory effects on erythema induced by all 4 substances tested and on edema induced by methyl nicotinate. The inhibition was probably due in part to percutaneous absorption and systemic effects of NSAIDs. There were differences between visual and LDF assessments, which stresses the importance of monitoring erythematous reactions of the skin both visually and with LDF.

Acrolein↗
PubMed1988

Effects of sorbitan sesquioleate on non-immunologic immediate contact reactions to benzoic acid.

In order to study the effects of an emulsifier on non-immunologic immediate contact reactions, 500, 250, 125, 62, and 31 mM benzoic acid (BA) was tested in 12 medical students on a skin area of the upper back treated with sorbitan sesquioleate in yellow petrolatum (20:80) 3 times daily for 2 days and on a contralateral skin area treated with petrolatum. The test areas were visually observed and the changes in the skin blood flow were monitored using laser-Doppler flowmetry 40 min after application. The reactions to 250 and 125 mM BA in petrolatum were stronger on the skin area treated with sorbitan sesquioleate than on the reference site treated with petrolatum. In visual observation and in laser-Doppler flowmetry, BA in the mixture of sorbitan sesquioleate and petrolatum (20:80) produced weaker reactions than in petrolatum, both on the sorbitan sesquioleate treated skin site and on the site treated with petrolatum.

Adult↗