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D Becker

Publications and source records attributed to D Becker.

At least 19 recordsLinked to original sources
PubMed2006

Late reactions to the patch-test preparations para-phenylenediamine and epoxy resin: a prospective multicentre investigation of the German Contact Dermatitis Research Group.

BACKGROUND: Late patch-test reactions, developing at day (D) 7 or later have been described for several allergens. Late reactions may reflect patch-test sensitization. Para-phenylenediamine (PPD) and epoxy resins (ER) are potent allergens and therefore may potentially induce patch-test sensitization. Up to now, there has been no prospective study on the frequency of late reactions in routine patch testing with these allergens. OBJECTIVES: To assess the frequency of late reactions to PPD and ER. PATIENTS/METHODS: In 1748 patients PPD (PPD-base, 1% pet.) and ER [based on diglycidylether of bisphenol A (DGEBA, 1% pet.)], and in 812 patients, nickel sulphate (5% pet.) were removed from the test panel of the standard series and applied on the medial side of the upper arm. Patch-test occlusion time was 24 h in 588 (PPD and ER) and 241 patients (nickel sulphate), respectively, and 48 h in 1160 (PPD and ER) and 571 (nickel sulphate) patients, respectively. Patch tests were read on D1-3 and D2-3, respectively; additional late readings were performed on D7, D14 and D21 after patch-test application. Patients who were not able to return for all scheduled late readings were telephoned on D7, D14 or D21, and questioned about a reaction at the test sites. Patients were instructed to perform daily self-examination from D4 onwards and to return immediately to the clinic if a reaction at the upper arm became visible. RESULTS: Data of 1428 patients (ER and PPD) and 638 patients (nickel) were evaluable. In 25 patients (1.8%), patch tests became positive not before D7, among them 21 reactions to PPD (1.5%) and four reactions to ER (0.3%). In five of seven patients, repeated patch tests with PPD disclosed patch-test sensitization as the cause of the late reaction. All late reactions, except for one, occurred in patients in whom patch tests were applied for 48 h. No late reactions were seen with nickel sulphate. CONCLUSIONS: PPD (1% pet.) elicited late reactions in 1.5% of routine patch tests, the majority of them probably being caused by patch-test sensitization. Therefore, the German Contact Dermatitis Research Group decided to remove PPD 1% pet. from the German standard series and to take efforts to optimize the patch-test conditions of PPD. One way to optimize PPD testing could be to reduce the exposure of PPD 1% to 24 h. Alternatively the patch-test concentration of PPD might be reduced.

Adolescent↗
PubMed2005

Site-specific recombination in Zea mays.

The elimination of marker genes after selection is recommended for the commercial use of genetically modified plants. We compared the applicability of the two site-specific recombination systems Cre/lox and Flp/FRT for marker gene elimination in maize plants. The selection marker gene pat surrounded by two identically directed lox or FRT sites was introduced into maize. Sexual crossing with plants harboring the corresponding constitutively expressed recombinase led to the precise and complete excision of the lox-flanked marker gene in the F1 progeny, whereas Flp-mediated recombination of FRT sequences occurred rarely. Further examination of site-specific integration was done by biolistic bombardment of immature embryos harboring only one lox site with a lox.uidA sequence with results indicating directed integration.

Bacteriophage P1↗
PubMed2005

[Evidence-based evaluation of the effect of Type IV Allergies on the reduction of fitness for work. Survey of occupational skin diseases].

Evidence-based guidelines about the distribution of type IV allergens of the European standard series in different professions and its occupational relevance are missing. Based on published data, epidemiological investigations, work related knowledge about industrial processes, and allergen specific properties, recommendations are given about the clinical impact in the working environment for the following allergens: acrylates/methacrylates, epoxy resins, dichromate, cobalt, nickel, formaldehyde, (chlor-)methylisothiazolone, p-phenylendiamine, colophony, thiurame, mercaptobenzothiazole, dithiocarbamate, n-isopropyl-n'-phenyl-p-phenylendiamine, fragrance mix, composite mix, and neomycinsulfate. These recommendations might improve the clearance rate and allergological evaluation of the occupational relevance of different delayed type sensitizations or allergens.

Allergens↗
PubMed2005

Simultaneous sodium lauryl sulphate testing improves the diagnostic validity of allergic patch tests. Results from a prospective multicentre study of the German Contact Dermatitis Research Group (Deutsche Kontaktallergie-Gruppe, DKG).

BACKGROUND: There is evidence that a higher skin susceptibility may induce nonspecific erythematous or weak positive reactions to contact allergens in patch testing. OBJECTIVES: To evaluate whether simultaneous application of sodium lauryl sulphate (SLS) along with diagnostic patch tests with contact allergens can provide information regarding skin irritability which may help to discriminate allergic from nonspecific irritant reactions to contact allergens. METHODS: Between July 2001 and June 2003, this prospective study collected patch test data of 5971 patients from 19 centres in Germany and Austria in the Information Network of Departments of Dermatology (IVDK). In addition to contact allergens (standard series and eight known 'problematic' allergens with a low reaction index and a high positivity ratio: 1,3-diphenylguanidine, amerchol L-101, benzalkonium chloride, benzoyl peroxide, cocamidopropyl betaine, octyl gallate, phenyl mercuric acetate and propylene glycol), patches with SLS 0.5% and 0.25% aq. were applied. Reactions to the allergens and to SLS were analysed at the IVDK data centre. The association between an erythematous or positive reaction to a certain allergen and an irritant reaction to SLS was assessed with logistic regression analysis, at the same time controlling for the influence of age and sex. RESULTS: Of the 29 allergens of the standard series, 23 and 21 gave a higher percentage of nonspecific erythematous reactions in patients with an irritant reaction to 0.25% and 0.5% SLS, respectively, in comparison with SLS-negative patients. All eight 'problematic' allergens gave an increased percentage of nonspecific erythematous reactions. Similarly, 22 and 21 allergens of the standard series gave a higher percentage of positive allergic reactions in patients with an irritant reaction to 0.25% and 0.5% SLS, respectively, and seven of the eight 'problematic' allergens gave a higher percentage of positive allergic reactions (exception: octyl gallate). For most allergens, the markers of skin reaction (reaction index and positivity ratio) were worse in SLS-positive patients. Differences were more pronounced when testing with SLS 0.25% than with SLS 0.5%. CONCLUSIONS: Because there is a convincing association between skin irritability (evaluated by SLS test) and the degree of skin reaction to contact allergens, the SLS test may help in deciding whether a doubtful erythematous or weakly 'positive' skin reaction should be interpreted as allergic or irritant.

Adult↗
PubMed2005

Excess mortality in Black compared with White patients with Type 1 diabetes: an examination of underlying causes.

AIMS: Excess mortality in Type 1 diabetes has previously been found among Black individuals. The aim of the present study was therefore to determine underlying causes. METHODS: A longitudinal study of 1261 [1184 White (93.9%) and 76 Black (6.0%)] individuals diagnosed with Type 1 diabetes between 1965 and 1979, at age<17 years from the Allegheny County, Pennsylvania and Children's Hospital of Pittsburgh registries. Subjects were contacted in 1999 to determine living status and, where appropriate, cause of death. Living status was determined in 1183 participants (93.8%). RESULTS: Of the 200 deaths overall, cause of death was determined in 157 subjects (79%); 31 dying from acute and 101 from chronic complications, and 25 from non-diabetes related causes. Seven deaths were investigated but no cause determined. Black participants had a significantly higher mortality rate compared with White participants for acute complications (hazard ratio=4.9, 95% confidence interval: 2.0, 11.6), but not for any other cause. There was a temporal decline in the 20-year mortality rates in both racial groups across the three cohorts diagnosed in 1965-69, 1970-74 and 1975-79. CONCLUSIONS: These results show that the excess mortality in Black people was attributed to acute complications which therefore should be a focus for prevention.

Adolescent↗
PubMed2005

Mexican physicians' knowledge and attitudes about the human papillomavirus and cervical cancer: a national survey.

OBJECTIVE: To assess Mexican physicians' knowledge about the human papillomavirus (HPV) and cervical cancer and their opinions and practices related to screening, managing, and counselling women on these topics. METHODOLOGY: In August 2002 we surveyed 1206 general practitioners (GPs) and obstetricians-gynaecologists (Ob-Gyns) working in a nationally representative sample of public and private facilities in urban Mexico. Eligible physicians completed a self administered questionnaire. We conducted a weighted analysis and used chi(2) tests to compare GPs and Ob-Gyns on outcome variables. RESULTS: 76% of recruited physicians responded to the survey. 43% of Ob-Gyns had performed a hysterectomy in the last year to treat a case of CIN I or II. With respect to HPV, while 80% of respondents identified the virus as the principal cause of cervical cancer, many lacked detailed knowledge about this association. Ob-Gyns were more likely than GPs to have heard about specific oncogenic strains of HPV (p<0.001). Nearly all respondents thought that women should be informed that HPV causes cervical cancer; nevertheless, physicians believed that positioning cervical cancer as a sexually transmitted infection (STI) could cause problems in partner relationships (60%), confusion (40%), and unnecessary anxiety among women (32%). CONCLUSIONS: Mexican physicians support patient education on the HPV-cervical cancer link. However, findings suggest the need to present clear messages to women (emphasising, for example, that only certain types of HPV are oncogenic), to consider the conflicts such information might create for couples, and to further educate physicians about this topic and about overall cervical cancer screening and treatment protocols.

Adult↗
PubMed2004

AtTPK4, an Arabidopsis tandem-pore K+ channel, poised to control the pollen membrane voltage in a pH- and Ca2+-dependent manner.

The Arabidopsis tandem-pore K(+) (TPK) channels displaying four transmembrane domains and two pore regions share structural homologies with their animal counterparts of the KCNK family. In contrast to the Shaker-like Arabidopsis channels (six transmembrane domains/one pore region), the functional properties and the biological role of plant TPK channels have not been elucidated yet. Here, we show that AtTPK4 (KCO4) localizes to the plasma membrane and is predominantly expressed in pollen. AtTPK4 (KCO4) resembles the electrical properties of a voltage-independent K(+) channel after expression in Xenopus oocytes and yeast. Hyperpolarizing as well as depolarizing membrane voltages elicited instantaneous K(+) currents, which were blocked by extracellular calcium and cytoplasmic protons. Functional complementation assays using a K(+) transport-deficient yeast confirmed the biophysical and pharmacological properties of the AtTPK4 channel. The features of AtTPK4 point toward a role in potassium homeostasis and membrane voltage control of the growing pollen tube. Thus, AtTPK4 represents a member of plant tandem-pore-K(+) channels, resembling the characteristics of its animal counterparts as well as plant-specific features with respect to modulation of channel activity by acidosis and calcium.

Animals↗
PubMed2004

Exploring knowledge and attitudes about emergency contraceptive pills among university students in Jamaica. A qualitative approach.

Emergency contraceptive pills (ECPs) are an important option for university students who may be at high risk for unplanned pregnancies. In the Caribbean, little research has been carried out on university student's knowledge and opinions of this method. This study uses qualitative methodology to explore knowledge and opinions on ECPs among university students attending The University of the West Indies (UWI) Mona campus. We conducted eight focus groups (n = 71) with female and male university students at The University of the West Indies, Kingston, Jamaica, in March 2000. The group discussions lasted approximately two hours. We tape-recorded discussions and then transcribed and analyzed them by coding responses according to themes. General knowledge of ECPs was high, but students lacked specific information about the method such as its time frame and its mechanism of action. Most students supported the method, especially after learning correct information. However, several students were concerned about its side effects and the potential for abuse or irresponsible use by young adults. Although the university students in this study lacked detailed information about ECPs, their opinion toward the method was favourable. We suggest further research to investigate the prevalence of misinformation about the method among other groups of Jamaicans.

Adolescent↗
PubMed2003

Regulation of the ABA-sensitive Arabidopsis potassium channel gene GORK in response to water stress.

The phytohormone abscisic acid (ABA) regulates many stress-related processes in plants. In this context ABA mediates the responsiveness of plants to environmental stresses such as drought, cold or salt. In response to water stress, ABA induces stomatal closure by activating Ca2+, K+ and anion channels in guard cells. To understand the signalling pathways that regulate these turgor control elements, we studied the transcriptional control of the K+ release channel gene GORK that is expressed in guard cells, roots and vascular tissue. GORK transcription was up-regulated upon onset of drought, salt stress and cold. The wilting hormone ABA that integrates responses to these stimuli induced GORK expression in seedlings in a time- and concentration-dependent manner and this induction was dependent on extracellular Ca2+. ABA-responsive expression of GORK was impaired in the ABA-insensitive mutants abi1-1 and abi2-1, indicating that these protein phosphatases are regulators of GORK expression. Application of ABA to suspension-cultured cells for 2 min followed by a 4 h chase was sufficient to manifest transcriptional activation of the K+ channel gene. As predicted for a process involved in drought adaptation, only 12-24 h after the release of the stress hormone, GORK mRNA slowly decreased. In contrast to other tissues, GORK expression as well as K+(out) channel activity in guard cells is ABA insensitive, allowing the plant to adjust stomatal movement and water status control separately.

Abscisic Acid↗
PubMed2003

Transforming growth factor beta1 immobilized adsorptively on Ti6Al4V and collagen type I coated Ti6Al4V maintains its biological activity.

Titanium and titanium alloys are often used for orthopedic and dental implants. Osseointegration of Ti6Al4V may be improved not only by precoating of the surface with extracellular matrix proteins like collagen type I but also by additional immobilization of growth factors. In the present study, transforming growth factor beta1 (TGF-beta1) which is known as an inducer of collagen synthesis was immobilized adsorptively on uncoated and collagen type I coated Ti6Al4V surfaces. TGF-beta1 was found immobilized slightly faster to collagen type I coated than to uncoated Ti6Al4V and released slower from the collagen coated material. Immobilized TGF-beta1 is biologically active for at least 3 weeks storage at 4 degrees C. Sterilization by ethylene oxide inactivates immobilized TGF-beta1. In osteoblasts cultured on implants with adsorptively immobilized TGF-beta1, mRNA level and specific catalytic activity of alkaline phosphatase as well as accumulation of calcium and phosphate were found reduced, whereas procollagen alpha1(I) mRNA level and the rate of collagen synthesis were increased.

Adsorption↗
PubMed2003

Do plasminogen activator inhibitor (PAI-1) or tissue plasminogen activator PAI-1 complexes predict complications in Type 1 diabetes: the Pittsburgh Epidemiology of Diabetes Complications Study.

AIMS: To examine the predictive power of plasminogen activator inhibitor-1 (PAI-1) and the complexes it forms with tissue plasminogen activator (tPA-PAI-1) for the two major Type 1 diabetes (T1D) complications (coronary artery disease (CAD) and overt nephropathy) in the context of standard risk factors. METHODS: Observational prospective study of 454 participants with childhood onset (< 17 years) T1D, aged 18+ years at baseline. PAI-1 and tPA-PAI-1 were determined using ELISA methodology. Follow-up (6 years) was limited to 382 individuals for CAD and 294 individuals for overt nephropathy, after excluding baseline cases. Total, HDL and LDL-cholesterol, triglycerides, HbA1, blood pressure, body mass index (BMI), waist-hip ratio (WHR), leucocyte count, Beck depression score and fibrinogen were also examined. RESULTS: The 56 incident cases of CAD had marginally lower PAI-1 and higher tPA-PAI-1 levels compared with those free of CAD. However, marginally higher PAI-1 and significantly higher tPA-PAI-1 (P = 0.04) levels were seen in those who developed nephropathy. After controlling for age, both PAI-1 and tPA-PAI-1 showed significant negative correlations with HDL-cholesterol, and positive correlations with triglycerides, WHR, HbA1 and fibrinogen. tPA-PAI-1 was also positively correlated with total and LDL-cholesterol. In multivariate analyses, neither PAI-1 nor tPA-PAI-1 was an independent predictor of CAD or overt nephropathy. CONCLUSIONS: These results suggest little association between PAI-1 and later CAD in patients with T1D. However, tPA-PAI-1 complexes may be involved in the pathogenesis of overt nephropathy.

Adult↗
PubMed2003

[Radio-frequency-ablation (RFA) with wet electrodes in the treatment of primary and secondary liver tumours].

INTRODUCTION: The majority of patients with primary and secondary tumours of the liver cannot be treated curatively by surgery. The treatment of these patients with radio-frequency thermoablation using perfused needle applicators (wet electrodes) was evaluated in a feasibility study. METHOD: Patients with primary and secondary tumours of the liver and contraindications against surgery or LTX were included into the feasibility study. RFA was performed percutaneously under ultrasound guidance. The patients were followed up sonographically and by computed tomography. RESULTS: 20 patients (9 male, 11 female) with 35 lesions were treated with RFA. 12 patients (22 tumour locations) suffered from HCC and 8 patients (13 tumour masses) had liver metastases (colorectal, breast, pancreas, carcinoid). The median age was 65.6 years (36 to 83 years). The median tumour size was 33.5 mm. 59 RFTA applications (1.7 applications per tumour mass) were performed. The mean duration of RFTA per patient was 16.2 minutes. During the procedure isotonic saline was injected at a mean flow rate of 6.63 ml/min. All patients received local anaesthesia. In 33 sessions an additional analgosedation was necessary (average dose 63.8 mg Pethidine and 1.4 mg Midazolam). In 2 cases a reduction of the haemoglobin level, occurred, necessitating a blood transfusion. 3/4 of the treated metastases could be eradicated completely. Within a median follow-up of 145 days no intrahepatic local recurrence but 4 distant metastases occurred. 2/3 of the treated HCC could initially be brought into complete remission (CR). After a median follow-up of 329 days 5 of the 8 initially successfully treated patients with HCC were still in complete remission. In 3 cases an intrahepatic local recurrence developed. CONCLUSION: RFA with wet electrodes is a safe, effective and inexpensive treatment for primary and secondary tumours of the liver, measuring less than 4 cm in diameter.

Adult↗
PubMed2003

[Detection of liver metastases--comparison of contrast--enhanced ultrasound using first versus second generation contrast agents].

AIM: To compare detection rates for liver metastases for conventional ultrasound, US using tissue harmonic imaging (THI), echo-enhanced pulse inversion harmonic imaging using Optison and Levovist. METHOD: In 73 patients with histologically proven gastrointestinal tumors spiral CT (S-CT), conventional US, US in the THI-mode, echo-enhanced ultrasound in the portal venous phase (ECI Optison ) and in the liver specific late phase (ECI Levovist) were performed and reviewed by blinded readers. RESULTS: 73 patients (25 female, 48 male, age 63 +/- 11) were included. S-CT detected 158 liver metastases. Conventional US detected 117, THI 119, ECI Optison 169 and ECI Levovist 166 liver metastases. Especially for small (< 2 cm) liver metastases and metastases near the diaphragm echo-enhanced ultrasound exceeded conventional US (p < 0.001). Between both echo enhancers there was no significant difference. CONCLUSION: Using echo enhancers increases the ultrasound detection rate significantly. Examination in the portalvenous phase using a second generation enhancer (Optison) is equal to a late-phase examination using Levovist.

Contrast Media↗
PubMed2003

Radiofrequency ablation of hepatocellular carcinoma with a saline solution perfusion device: a pilot study.

PURPOSE: The majority of patients with hepatocellular carcinoma (HCC) cannot be treated with surgery. This study evaluated the treatment of patients with radiofrequency ablation (RFA) with use of needle applicators perfused with isotonic saline solution. MATERIALS AND METHODS: Twenty patients with a maximum of three HCCs as large as 60 mm and a contraindication to partial liver resection or orthotopic liver transplantation were enrolled in the study. They were treated with ultrasound-guided RFA with use of perfused needle applicators and followed with sonography and computed tomography. RESULTS: Twenty patients (14 men, six women) with a total of 29 HCCs were treated with RFA. In total, 56 RFA treatments were performed. Mean HCC size was 31 mm (range, 10-60 mm). Two cases of self-limiting bleeding requiring transfusion of blood products took place. Complete response (CR) was achieved in 85% of patients (17 of 20). Partial response occurred in three tumors 45 mm in diameter or larger. There was a total of six local recurrences in five patients (25% of patients, 21% of tumors). Six patients (30%) exhibited distant recurrence, two of whom also showed local recurrence. In three patients, repeat treatment led to renewed CR. After a median follow-up of 445 days (range, 114-1,071 days), 12 patients (71% of the 17 patients with initial CR) still showed CR. Twelve patients (60% of all patients, 71% of those with initial CR) survived. Three of the eight patients who died were free of viable tumor at the time of death. CONCLUSIONS: RFA with use of perfused needle applicators shows promise as an effective method for treating inoperable HCC. The most frequent complication was bleeding.

Aged↗
PubMed2003

Detailed morphology and distribution of gap junction protein associated with cells from the intra-articular disc of the rat temporomandibular joint.

The present study details structural aspects of the cells of the rat intra-articular disc (IAD) of the temporomandibular joint. At the light and electron microscope level, the outline of the cells varied, although a number appeared oval/rounded. Ultrastructurally, the cells contained moderate amounts of the intracellular organelles associated with protein synthesis. Cell processes were not a prominent feature seen using these techniques. However, using confocal microscopy, phalloidin staining revealed the presence of numerous, actin-rich, long, thin, branching processes emanating from the cell membranes. Double staining for connexin 43 revealed that the cell processes showed dense, punctate positive staining for this gap junction protein along their whole length. These observations provide the basis for a transport mechanism for nutritive molecules from the periphery of the IAD (where blood vessels are present) to the central portions of the disc (where blood vessels are absent).

Actins↗
PubMed2002

Proliferation and differentiation of rat calvarial osteoblasts on type I collagen-coated titanium alloy.

Several attempts have been made to improve osseointegration of titanium alloy as an implant material by modification of its surface. In the present study, proliferation, differentiation, and mineralization of osteoblasts on type I collagen-coated Ti6Al4V were investigated. The activity of alkaline phosphatase and the accumulation of calcium by osteoblasts grown on titanium alloy were significantly higher compared to cells grown on polystyrene. Precoating of the implant surface with type I collagen did not extensively affect proliferation, the activity of alkaline phosphatase, collagen synthesis, calcium accumulation, or the mRNA levels for collagen I alpha1, osteopontin, osteocalcin, MMP-2, and TIMP-2. Maximum collagen synthesis by osteoblasts was observed at day 4 of culture independent of the type of implant material. The specific activity of alkaline phosphatase reached its maximum at day 18 of culture. Accumulation of calcium and elevated mRNA levels for osteocalcin were found at day 22. These results indicate that collagen-coating alone is not sufficient to accelerate differentiation of rat calvarial osteoblasts on Ti6Al4V.

Alloys↗