Search PubMed⌕ Search

Biomedical subjects

C Hansson

Publications and source records attributed to C Hansson.

At least 19 recordsLinked to original sources
PubMed2006

High-performance liquid chromatography analysis of rubber allergens in protective gloves used in health care.

A high-performance liquid chromatography (HPLC) method developed for analysis of zinc dithiocarbamates was validated and used to perform a survey of disposable medical gloves used in southern Sweden. The gloves were extracted with acetone at room temperature for 10 min by shaking. The extracts were injected into a polyether ether ketone lined HPLC column, and peaks were analysed by a diode-array detector. The survey shows that of 19 gloves analysed, 10 contained zinc diethyldithiocarbamate (0.070-3.5 mg/g), 3 contained zinc pentamethylenedithiocarbamate (1.0-4.3 mg/g), 4 contained zinc dibutyldithiocarbamate (0.9-1.1 mg/g), and 2 contained 2-mercaptobenzothiazole (0.005-0.008 mg/g). None of them contained thiurams.

Allergens↗
PubMed2005

Extraction of haptens from solid products and their delivery to the skin, exemplified by dithiocarbamates from rubber gloves.

Allergic contact dermatitis is often caused by solid products such as rubber gloves. Patch testing with the product as is often gives negative results. Extraction of the haptens into an organic solvent is commonly performed to achieve a more correct investigation. The technique used for extraction of haptens from solid materials is only sporadically described. In this study, we investigated and optimized the yields of dithiocarbamates obtained by extraction from rubber gloves. The influence of solvent, extraction time and the procedures for extraction are evaluated. The delivery of zinc dibutyldithiocarbamate from the patch test preparation to the skin is determined.

Chromatography, High Pressure Liquid↗
PubMed2005

The evolution of host use and unusual reproductive strategies in Achrysocharoides parasitoid wasps.

We studied host selection and exploitation, two crucial aspects of parasite ecology, in Achrysocharoides parasitoid wasps, which show remarkable host specificity and unusual offspring sex allocation. We estimated a molecular phylogeny of 15 Achrysocharoides species and compared this with host (plant and insect) phylogenies. This tri-trophic phylogenetic comparison provides no evidence for cospeciation, but parasitoids do show phylogenetic conservation of the use of plant genera. Patterns of sequence divergence also suggest that the parasitoids radiated more recently (or evolved much faster) than their insect hosts. Three main categories of brood production occur in parasitoids: (1) solitary offspring, (2) mixed sex broods and (3) separate (split) sex broods. Split sex broods are very rare and virtually restricted to Achrysocharoides, while the other types occur very widely. Our phylogeny suggests that split sex broods have evolved twice and provides evidence for a transition from solitary to mixed sex broods, via split sex broods, as predicted by theory.

Animals↗
PubMed2003

Larval therapy--an effective method of ulcer debridement.

Since ancient times, larval therapy has been reputed to help wound healing. Its use has recently been rediscovered and it is now enjoying increasing interest in clinical practice, as well as in research. We have investigated the effects of larval therapy on wounds in an open study of 74 patients with necrotic or sloughy chronic ulcers of different aetiologies. We found larval therapy to effectively debride 86% of the necrotic ulcers, and a single application was clinically beneficial in two-thirds of the patients. Failure to debride was mostly attributable to larval death. No ulcer type was shown to be more suited to larval therapy than others; however, there was an excellent response in all 29 patients with diabetes. Larval therapy was also noted to reduce odour in 58% of the 31 foul-smelling ulcers of mixed aetiology. No serious side-effects were observed. One-quarter of the study group experienced less pain during treatment, while 41% felt no difference in pain, and, although 34% noted an increase in pain, most of these patients wanted to continue the treatment because of subjective and objective visual improvement in wound debridement. In conclusion, we found larval therapy to be effective for debriding ulcers, easy to use and well accepted by the patients.

Adult↗
PubMed2002

Spontaneous formation of thiuram disulfides in solutions of iron(III) dithiocarbamates.

Dithiocarbamates are used as pesticides and rubber additives. Dithiocarbamates are the reduced forms of thiuram disulfides and both of these groups of substances induce allergic contact dermatitis. The allergic cross-reactivity pattern between dithiocarbamates and thiurams is unclear. The aim of this study was to investigate why these cross-reactions occur sometimes but not always. HPLC-analysis of buffer solutions of iron(III) dithiocarbamates demonstrated that thiuram disulfides were formed spontaneously and rapidly in high yield. No such oxidation was observed in solutions of copper(II), zinc(II), or sodium dithiocarbamates. However, sodium diethyldithiocarbamate and zinc diethyldithiocarbamate were oxidized in buffer solution when ferric salt was added. The influence of different metal ions on the oxidation reaction is probably an explanation for the cross-reactivity patterns seen between dithiocarbamates and thiurams. These findings also show that careful handling is necessary in analytical and biological studies with solutions of iron(III) dithiocarbamates. Oxidation of dithiocarbamates in aqueous buffer at physiological pH has not been shown before.

Chromatography, High Pressure Liquid↗
PubMed2001

Stability of thiuram disulfides in patch test preparations and formation of asymmetric disulfides.

The thiuram mix used in patch testing originally contains 4 compounds. However, chemical analysis of the test preparation revealed that several new compounds are spontaneously formed during storage. The structures of these compounds have been determined and the rate of their formation has been studied in buffer solution at pH 7.4. After a few hours, a large amount of mixed disulfides are formed in solutions originally containing only symmetric disulfides. The impact on the test result of the formation of asymmetric disulfides has been investigated by testing on thiuram-sensitive volunteers with different preparations of mixed thiuram disulfides. In our study, the formation of new asymmetric thiuram disulfides from the original symmetric thiuram disulfides in the test preparation had no influence on the result of the patch testing. However, as the chemical analysis showed that the mix composition changes during the period when the preparations are used, and differs between suppliers, the question is raised as to whether it is acceptable to use test preparations with a composition that is different from that labelled on the protocol.

Allergens↗
PubMed2000

Facial profile and dental changes before, during and after treatment with Hansaplate/Headgear.

In this prospective study the changes of facial profile and dentition in 19 boys and 19 girls treated for 1 year with Hansaplate/Headgear were analyzed yearly over a 4-year period. On average the boys were 10.2 and the girls 9.2 years old at the first recording, i.e., 1 year pretreatment. The actual values are compared with standard growth data presented by Bathia and Leighton (1993). Irrespective of the initial face morphology, the Hansaplate/Headgear appliance straightened the facial hard and soft tissue profiles favorably. The upper lip became more retruded while the lower lip was unaffected by therapy. During the 2-year post-treatment period these changes continued, probably as a consequence of growth. The overjet was reduced by 5 mm during treatment and was found to be quite stable 2 years after treatment.

Analysis of Variance↗
PubMed2000

Activation and cross-reactivity pattern of a new allergen in adhesive plaster.

N,N'-disalicylidene-1,2-diaminopropane is a copper inhibitor present in some adhesive plasters, rubber products and gasoline. Upon contact with water it is hydrolyzed to salicylaldehyde and 1,2-diaminopropane. All patients in this study showed positive patch-test reactions to N,N'-disalicylidene-1,2-diaminopropane, and also to 1,2-diaminopropane and ethylenediamine. None reacted to salicylaldehyde. Patch testing with different N,N'-disalicylidene-derivatives showed localization of the amino groups in positions 1 and 2 to be a prerequisite of cross-reactivity to 1,2-diaminopropane and ethylenediamine. An extraction procedure and a high-performance liquid chromatography (HPLC) method for the analysis of adhesive plasters is described. Studies of the hydrolysis of the copper inhibitor at physiological pH showed rapid formation of 1,2-diaminopropane under biomimetic conditions.

Adhesives↗
PubMed2000

Tyrosinase-mediated formation of a reactive quinone from the depigmenting agents, 4-tert-butylphenol and 4-tert-butylcatechol.

Exposure of the skin to certain phenols or catechols such as 4-tert-butylphenol (TBP) and 4-tert-butylcatechol (TBC) may cause leukoderma. These substances are used in the polymer industry and numerous cases have been reported. Several theories of the mechanism for chemical leukoderma have been suggested. In the present study, TBP and TBC are shown to be oxidised by tyrosinase. The oxidation of TBC yields a quinone that is further investigated on its reactions with cysteine or glutathione (GSH). The products formed are isolated and identified by mass spectrometry and nuclear magnetic resonance as being 4-tert-butyl-6-S-cysteinylcatechol (cys-TBC) and 4-tert-butyl-6-S-glutathionylcatechol (GS-TBC). The reactive quinone is a strongly electrophilic substance that rapidly reacts with GSH. A depletion of the GSH defence system may give conditions where the quinone lives long enough to effect its toxic properties. The influence of the reactive tert-butylquinone on enzymatic activities is demonstrated by the inhibition of glyceraldehyde-3-phosphate dehydrogenase.

Agaricales↗
PubMed1999

[Infections and treatment of chronic leg ulcers: the use of antibiotics is too excessive, restrictive prescription is recommended].

Chronic venous leg ulcers are contaminated or colonised with bacteria that seldom affects ulcer healing. Signs of clinical infection appear in only a minority of chronic ulcers. In spite of this, data show a high consumption of antibiotics in this group of patients. Treatment with antibiotics is indicated only when clinical signs of infection or obvious risk factors are present or when Streptococcus pyogenes is isolated from the ulcer. In these cases an oral antistaphylococcal agent (semisynthetic penicillinase-resistant penicillin or first generation oral cephalosporin) is recommended as the first choice. Enterococci, anaerobic bacteria and gram-negative bacteria including pseudomonas spp. often colonise chronic ulcers, but do not usually cause antibiotic requiring infection.

Anti-Bacterial Agents↗
PubMed1998

[Iodine-induced hyperthyroidism after cadexomer iodine treatment of leg ulcers].

The article consists in two case reports of eldery patients who developed hyperthyroidism after cadexomer iodine treatment of small leg ulcers. The first was an 87-year-old woman who developed anxiety, hoarseness and tachycardia after five months treatment of a 12 cm2 leg ulcer with 350 g cadexomer iodine. Her serum level of free thyroxine (FT4) was 23.1 pmol/l (normal range, 11.7-28.0), and that of thyroid-stimulating hormone (TSH) 0.01 mIU/l (normal range, 0.1-3.0). She had had a nodular goitre for thirty years. The second was an 86- year-old woman who developed depression and confusion after three months' treatment of an 8 cm2 leg ulcer with 170 g cadexomere iodine. Her serum level of FT4 was 30.0 pmol/l, and that of TSH 0.005 mIU/l. Both patients underwent Tc99m pertechnetate scanning and iodine uptake measurement with a view to treating the hyperthyroidism with radio-iodine. However, as iodine uptake was inhibited in both cases, radio-iodine treatment was impossible, and symptomatic treatment and antithyroid drugs had to be used. Thus, it is concluded that topical treatment with cadexomer iodine can induce hyperthyroidism difficult to manage clinically as the treatment options are limited, which should be borne in mind when cadexomer iodine treatment is considered.

Administration, Topical↗
PubMed1998

Periodontal conditions following surgical and orthodontic treatment of palatally impacted maxillary canines--a follow-up study.

This follow-up study reports on the periodontal status 1 to 18 years after the completion of orthodontic treatment of unilateral palatally impacted maxillary canines and their adjacent incisors and premolars. Registrations were performed on 42 patients, 19 to 59 years old (mean 35 years) at investigation. An orthodontic pin with eyelet had been placed after exploration of the canine and, in some cases, bone removal. A flap had been raised and resutured after bone removal in 11 cases. The results showed greater mesial probing depth of the canines on the treated side, on the adjacent lateral incisors distolingually, and on the first premolars mesiolingually. Marginal bone level was found to be lower on the distal aspect of the treated canines and adjacent laterals. In general, the results showed a good gingival and periodontal status with slight differences between treated and untreated sides.

Adult↗
PubMed1998

The Fy(x) phenotype is associated with a missense mutation in the Fy(b) allele predicting Arg89Cys in the Duffy glycoprotein.

The molecular basis of the three major alleles (Fy(a)/Fy(b)/Fy) of the Duffy (FY) blood group system has recently been established but the Fy(x) phenotype associated with weak expression of the Fy(b) and other FY antigens is poorly understood. In the Fy(x) genes of five unrelated British and Swedish donors with the Fy(a+b+weak) phenotype we found two missense mutations predicting amino acid changes Arg89Cys and Ala100Thr in the FY glycoprotein. The same mutations were found in two Fy(a-b+weak) samples from individuals of Swedish and Algerian origin. Their red blood cells showed a marked decrease in Fy(b), Fy3 and Fy6 expression measured by routine serology and flow cytometry. The rare FY genotypes Fy(x)Fy(x) and Fy(x)Fy were confirmed by family studies and DNA sequencing. Screening by allele-specific primer PCR (ASP-PCR) for these mutations among 100 Caucasian and 100 Black random blood donors indicated allele frequencies of 2.5% and 0% respectively. Ala100Thr alone was present in 33% of the Caucasians (but none of the Blacks) with no weakening of FY expression. A novel allele at the FY locus associated with the Fy(x) phenotype was studied. Mistyping of this weak Fy(b) antigen in clinical transfusion medicine may lead to delayed haemolytic transfusion reactions in immunized patients. A potential role for genomic typing is proposed.

Alleles↗