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  • 1
    Electronic Resource
    Electronic Resource
    Contact allergens, but not irritants, alter receptor-mediated endocytosis by human epidermal Langerhans cells (1999)
    Oxford BSL : Blackwell Science Ltd
    British journal of dermatology 140 (1999), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Allergic contact dermatitis is a T-cell-mediated inflammation, induced by contact with sensitizers and occurring through the release of epidermal cytokines and the activation of epidermal Langerhans cells (LCs). The aim of this study was to analyse early events of LC activation induced either by contact allergens or by irritants devoid of any contact allergenic properties, in order to obtain an in vitro method to discriminate between these two groups of molecules. Various contact sensitizers and irritants were studied for their effects on the endocytosis of major histocompatibility complex class II (MHC-II) molecules by freshly-isolated human epidermal LCs. As observed by flow cytometry, a spontaneous decrease in the surface expression of MHC-II (HLA-DR) molecules, linked to spontaneous internalization of the MHC-II molecules by LCs, was obtained by moving freshly-isolated LCs from 4 °C to 37 °C. Pre-incubation of LCs with either sensitizers or irritants increased the spontaneous internalization of HLA-DR molecules with a similar magnitude, but no clear discrimination between sensitizer and irritant effects was obtained by flow cytometry analysis. In contrast, confocal microscopy enabled discrimination between the effects of sensitizers and irritants: sensitizer-treated samples showed internalized HLA-DR molecules aggregated in large vesicles with very bright fluorescence; irritant-treated samples were not different from untreated controls and showed compact HLA-DR molecules in small vesicles with diffuse fluorescence, and mostly localized in the submembranous zone. Electron microscopy demonstrated that sensitizer-treated LCs internalized HLA-DR molecules preferentially in lysosomes collected near the nucleus, whereas the irritant-treated and non-treated LCs internalized these molecules in the prelysosomes only near the cell membrane. We conclude that contact allergens and irritants induce distinct patterns of HLA-DR endocytosis, which may be useful for the development of in vitro screening tests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2133.1999.02650.x
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  • 2
    Electronic Resource
    Electronic Resource
    Chronic Administration of Leptin into the Lateral Ventricle Induces Sexual Maturation in Severely Food-restricted Female Rats (1998)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 10 (1998), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In many species, delayed sexual maturation occurs when metabolic conditions are not satisfactory. Recently, leptin was shown to be involved in the regulation of food intake and body mass. Furthermore, leptin administration was shown to advance sexual maturation in mice and to rescue sexual function in adverse metabolic conditions. We examined plasma leptin levels in female rats during development and evaluated the role of leptin on sexual maturation in rats subjected to food restriction. In normal rats, plasma leptin levels were low at day 24 of life, then steadily increased during the juvenile period, reaching 740 ±56 pg/ml at 40 days at time of vaginal opening (VO) and further increasing by day 60 (957±73 pg/ml). Food restriction initiated at day 25 strongly impaired this increase, in proportion to the severity of the restriction. With a daily food intake reduced to 7–8 g/day, that permanently prevented VO, plasma leptin levels were very low at day 53 (169 ±67 pg/ml). Following switch to ad libitum feeding, plasma leptin reached high levels within 2 days (1577±123 pg/ml), and VO occurred 4 days later. If the severe food restriction was maintained and a central infusion of leptin (10 μg/day) was initiated, a significant decrease in body weight compared with vehicle-infused controls was observed. In these conditions, VO occurred in eight out of the nine leptin-treated rats, representing induction of the process of sexual maturation confirmed by increases in ovarian and uterine weights. This induction of sexual maturation exclusively results from a central effect of leptin because no leak of the icv administered leptin to the general circulation was observed. These data suggest that the rising plasma levels of leptin in the prepubertal period represent a signal to the brain indicating that the young animal is metabolically ready to go through the process of sexual maturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2826.1998.00247.x
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  • 3
    Electronic Resource
    Electronic Resource
    Neuroendocrine dysplasia in mice lacking protein tyrosine phosphatase σ (1999)
    [s.l.] : Nature America Inc.
    Nature genetics 21 (1999), S. 330-333 
    Details
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Protein tyrosine phosphatase σ (PTP-σ, encoded by the Ptprs gene) is a member of the LAR subfamily of receptor-like protein tyrosine phosphatases that is highly expressed during mammalian embryonic development in the germinal cell layer lining the lateral ventricles of the developing brain, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/6859
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  • 4
    Electronic Resource
    Electronic Resource
    UVA-induced immune suppression in human skin: protective effect of vitamin E in human epidermal cells in vitro (1996)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 134 (1996), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary UVA (320–400nm) radiation damage to membranes, proteins, DNA and other cellular targets is predominantly related to oxidative processes. In the present study, we demonstrated that cutaneous UVA-induced immunosuppression can be related, at least in part, to the appearance of these oxidative processes. The UVA-induced oxidative processes in freshly isolated epidermal cells were monitored by measuring the thiobarbituric acid reactive substances (TBARS) as an index of peroxidation. The in vitro immunosuppressive effects of UVA were demonstrated by measuring the allogeneic lymphocyte proliferation induced by epidermal cells or purified Langerhans cells in the mixed epidermal cell–lymphocyte reaction (MECLR). In addition, the effects of a potent antioxidant (vitamin E) on these two UVA-induced processes were analysed. Our results showed that the antigen-presenting function of Langerhans cells measured in the MECLR is dose-dependently decreased by UVA radiation (up to 20 J/cm2). Overnight incubation of epidermal cells with vitamin E (400 μmol/1) before irradiation partially protected epidermal cells from the immunosuppressive effects of UVA radiation, and decreased TBARS release into the supernatant (a decrease of 35% compared with a control without vitamin E). Our results suggest that UVA radiation may alter cellpresenting antigen function partly via the generation of reactive oxygen species which trigger peroxidative processes, and these data contribute to the understanding of the role of oxidative mechanisms in immune suppression induced by UVA radiation. Our in vitro model can be used to quantify UV-mediated epidermal cell damage and the degree of immune photoprotection provided by various agents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.1996.d01-732.x
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  • 5
    Electronic Resource
    Electronic Resource
    Feynman's Operational Calculus and Evolution Equations (1997)
    Springer
    Acta applicandae mathematicae 47 (1997), S. 155-211 
    Details
    ISSN: 1572-9036
    Keywords: Feynman's operational calculus for noncommuting operators ; Feynman's time-ordering convention ; time-ordered perturbation series ; disentangling ; evolution equations ; Feynman path integral ; semigroups of operators ; nonlocal potentials ; generalized path integral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We give an exposition and an extension of the ideas of Feynman's time-ordered operational calculus for noncommuting operators. Various directions for 'disentangling' functions of such operators are provided by measures on the time intervals in question. We concentrate especially on exponentials of sums of noncommuting operators and prove that the unique solution of a broad class of evolution equations is given by the time-dependent operators arrived at by disentangling such exponential expressions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005773828749
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  • 6
    Electronic Resource
    Electronic Resource
    Transurethral thermotherapy using the Prostatron device (1998)
    Springer
    World journal of urology 16 (1998), S. 89-95 
    Details
    ISSN: 1433-8726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This paper reviews the available data on low- and high-energy transurethral microwave thermotherapy (TUMT) in the treatment of patients with benign prostatic hyperplasia (BPH). Furthermore, it provides a perspective for this minimally invasive treatment modality in the selection of patients and in future developments. In evaluations of the two software modalities, several clinical studies have proved them to be effective. Whereas the lower-energy software seems to be the better choice for treatment of patients with lower urinary tract symptoms who have a lower grade of outlet obstruction and a smaller prostate, the higher-energy mode should be used to deobstruct and can be used in patients with larger prostates and moderate to severe outlet obstruction. Although baseline parameters can be used to predict the response to treatment in the higher-energy software mode, the total amount of energy remains very important for the final outcome, and future efforts should be encouraged to quantify prostate vascularization and histology in relation to transurethral microwave heating. Furthermore, future developments should focus on shorter treatment times and minimization of morbidity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003450050032
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  • 7
    Electronic Resource
    Electronic Resource
    LMJ Status Report (1999)
    Springer
    Europhysics news 29 (1999), S. 235-235 
    Details
    ISSN: 1432-1092
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00770-998-0235-5
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  • 8
    Electronic Resource
    Electronic Resource
    Eigenfunctions of the Koch snowflake domain (1995)
    Springer
    Communications in mathematical physics 172 (1995), S. 359-376 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract We obtain non-tangential boundary estimates for the Dirichlet eigenfunctions ϕ n and their gradients {∇ϕn } for a class of planar domains Ω with fractal boundaries. This class includes the quasidiscs and, in particular, snowflake-type domains. When applied to the case when Ω is the Koch snowflake domain, one of our main results states that {∇ϕ1(ω)} tends to ∞ or 0 as ω approaches certain types of boundary points (where ϕ1 〉 0 denotes the ground state eigenfunction of the Dirichlet Laplacian on Ω). More precisely, let Ob (resp., Ac) denote the set of boundary points which are vertices of obtuse (resp., acute) angles in an inner polygonal approximation of the snowflake curve ∂Ω. Then given νεOb (resp., νε Ac), we show that {∇ϕ1(ω)}→∞ (resp., 0) as ω tends to ν in Φ within a cone based at ν. Moreover, we show that blowup of {∇ϕ1} also occurs at all boundary points in a Cantor-type set. These results have physical relevance to the damping of waves by fractal coastlines, as pointed out by Sapovalet al. in their experiments on the “Koch drum”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02099432
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  • 9
    Electronic Resource
    Electronic Resource
    From laparoscopic training on an animal model to retroperitoneoscopic or coelioscopic adrenal and renal surgery in human (1995)
    Springer
    Surgical endoscopy and other interventional techniques 9 (1995), S. 699-701 
    Details
    ISSN: 1432-2218
    Keywords: Laparoscopy ; Retroperitoneum ; Adrenalectomy ; Endocrine disorders ; Nephrectomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract So far, laparoscopic approaches to kidney and adrenal have been limited because of their retroperitoneal location. We here report eight renal and adrenal endoscopic procedures performed in seven patients: two adrenalectomies for hyperaldosteronism, one adrenalectomy for isolated metastasis from an adenocarcinoma of the lung; two nephrectomies for end-stage infected hydronephrosis, two partial nephrectomies for small circumscribed lesions of the kidney, and one endoscopic resection for pain relief of a voluminous cyst at the kidney. The approach was transperitoneal in two cases and retroperitoneal in five cases using the retropneumoperitoneum insufflation technique. One patient was operated by a combined approach using the retro- and transperitoneal routes. All procedures were successfully completed endoscopically. The retroperitoneoscopic approach of the kidney is safe and does not interfere with the peritoneal organs. Its working space is tenuous, but allows a direct access on the kidney with good exposure of its pedicle. For adrenal surgery, the retroperitoneoscopic dissection is more difficult, because movements of instruments are often impaired by the closeness of the costal margin and the iliac crest. However, in case of difficulties we found it very convenient to switch from a retroperitoneal endoscopic approach to a combined coelioscopic and retroperitoneoscopic operation. Far from excluding each other, both approaches are complementary, particularly for difficult situations (i.e., previous peritoneal or retroperitoneal surgery).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00187943
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  • 10
    Electronic Resource
    Electronic Resource
    Multicentric experience of the Belgian Group for Endoscopic Surgery (BGES) with endoscopic adrenalectomy (1997)
    Springer
    Surgical endoscopy and other interventional techniques 11 (1997), S. 1065-1067 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Adrenalectomy — Pheochromocytoma — Endocrine disorders — Retroperitoneum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Adrenalectomy is not a frequent operation. Therefore the newly developed laparoscopic approach is sporadically performed by surgeons dealing with endocrine disorders. Methods: Some 54 videoendoscopic adrenalectomies performed on 52 patients by five surgical teams between October 1993 and December 1996 were prospectively evaluated. Results: Indications for endoscopic adrenalectomy were pheochromocytoma (n= 17), primary hyperaldosteronism (n= 15), Cushing's adenoma or disease (n= 7), nonsecreting adenoma (n= 7), single metastasis from adenocarcinoma (n= 2), adenoma with dehydroepiandrostenedione (DHEAS) hypersecretion (n= 3), and ACTH-secreting metastases from a thymoma (n= 1). Of the 54 adrenalectomies performed, 31 were of the left gland, 19 of the right and two bilateral. Laparoscopic adrenalectomy was successful in 50 patients (96%). Median tumor size was 4 cm (range 1.5–12), median operation duration was 80 min (range 59–360), and median postoperative stay was 4 days (range 2–13). One patient required blood transfusion. Conclusions: Endoscopic adrenalectomy can safely be performed—even sporadically—by surgeons well versed in adrenalectomy techniques for endocrine disorders and trained in endoscopic surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900530
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