Biomedical subjects

R Kaufmann

Publications and source records attributed to R Kaufmann.

At least 235 records · Page 13Linked to original sources

PubMed1991

Cell surface glycoproteins define distinct states of eccrine gland differentiation.

The capability to distinguish eccrine gland cells of the ductal compartment from the secretory portion on the molecular level, as well as from epidermal keratinocytes and other skin cells, is of importance for the study of eccrine differentiation and function. Furthermore, the assessment of differences between the cell systems is useful for the characterization of benign and malignant neoplasms derived from eccrine glands. In the present study, we analysed the expression of four selected epithelial cell surface glycoproteins (gp 80, gp 38, gp 115 and gp 200) in eccrine glands using specific monoclonal antibodies. We found that the glycoproteins are differentially expressed in the ductal compartments and in the secretory portion of the glands, as well as in normal epidermis and other skin cells. This permitted the assignment of specific phenotypes to cells of the ductal compartment and to those of the secretory portion.

Antibodies, Monoclonal↗

PubMed1991

Plasma-induced surface modifications on silicone intraocular lenses: chemical analysis and in vitro characterization.

In contrast to the high standard of intraocular lens implantation today, lens fixation and the occurrence of secondary opacifications are still not satisfactory. We are working on an implant that builds a stable connection to the surrounding lens-capsule. Disc-shaped lenses made of poly(dimethylsiloxane) were treated with different kinds of plasma to bring functional groups to the surface. This allows further macromolecular coating. The results of the surface modifications were characterized by electron spectroscopy for chemical analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and cell culture experiments. O2 plasma induces a rapid increase of functional groups on the lens surface. CO2 plasma has to be used for longer treatment periods to achieve the same increase, but as SEM shows, did not lead to surface damage up to periods of 300 s. Using O2 plasma for longer than 60 s, a crack formation occurred. Therefore, CO2 plasma may be a more effective and sensitive tool in grafting functional groups to the surface.

Biocompatible Materials↗

PubMed1991

Mastitis among lactating women: occurrence and risk factors.

Puerperal mastitis is a potentially serious illness among lactating women which traditionally has been thought to be associated with primiparity, stress, improper nursing technique, and incomplete emptying of the breast. However, none of these putative associations has been examined analytically in recent years. Further, the incidence of mastitis in the United States has not been estimated since 1975, although the prevalence of breastfeeding has increased dramatically since then. In this retrospective cohort study of 966 lactating women, the cumulative incidence of mastitis in the first seven weeks postpartum was 2.9%. This incidence was associated with professional, technical, or managerial occupation in both parents (rate ratio = 12.29; 95% CI: 1.62, 93.43) and with giving birth in the hospital delivery room, rather than the labor room (rate ratio = 4.05; 95% CI: 0.92, 17.83). Parity was not associated with risk of mastitis in this sample.

Adolescent↗

PubMed1991

[Photoallergic reaction to olaquindox].

Olaquindox, an antibiotic belonging to the quinoxaline group, is a growth promoter used in pig breeding. A farmer developed a photoallergic contact eczema to it, which progressed to a persistent light reaction. Besides this, we found a photosensitivity to chlorpromazine, a tranquillizer that is also used in pig breeding. In addition, after using potent light-protective drugs containing UV-A and UV-B filters, this patient developed a (photo)allergy to different filter substances. The photoallergy to olaquindox was caused by mixing a food additive containing olaquindox with the pigswill for both young and adult animals. We point out the dangers (potent photoallergen, cancer induction) resulting from the widespread use of this substance in the EC.

Animal Husbandry↗

PubMed1991

[Experience with hydrophilic silicone disc intraocular lenses].

When oxygen plasma was used for plasma etching it was possible to hydrophilize the surface of silicone intraocular lenses (IOLs) without changing the chemical composition or the properties of deeper layers of the polymer. The modification was characterized by surface analysis. (Electron spectroscopy = XPS, contact angle estimations) and by scanning electron microscope. A cytotoxic influence of the modified surface could be excluded by cell culture experiments in which we evaluated cell spreading, cell morphology, DNA synthesis and protein synthesis. In vivo experiments on rabbits showed that the postoperative foreign body reaction was not significantly influenced by the hydrophilization of the IOL surface. Over the entire follow-up period (12 weeks), there was a reduced tendency to induce posterior synechiae in the group with hydrophilized lenses (P = 0.009). The number of dislocations and the incidence of posterior opacification did not differ significantly; on the other hand there were indications of improved adhesion to the posterior lens capsule of the hydrophilized IOL.

Animals↗

PubMed1990

Integrins of normal human epidermis: differential expression, synthesis and molecular structure.

The expression of integrin cell surface receptors in normal skin and their synthesis and molecular structure in keratinocyte cultures was investigated. The reactivity of four different polypeptides of the integrin family (alpha 2-, alpha 3-, alpha 6- and beta 1-chains) was demonstrated in the basal cell layer of normal epidermis. Studies of labelled keratinocyte cell lines showed that the polypeptides were expressed as alpha 2 beta 1, alpha 3 beta 1 and alpha 6 beta 4 integrins. Only the alpha 6 beta 4 integrin showed polarization towards the basement membrane attachment site of basal layer keratinocytes, and was preferentially expressed at microvillous projections. In contrast, alpha 2 beta 1 and alpha 3 beta 1 integrins were equally expressed throughout the basal cell plasma membrane.

Basement Membrane↗

PubMed1990

Pulsed 2.94-microns erbium-YAG laser skin ablation--experimental results and first clinical application.

In the present study we compared skin-ablative effects produced by 2.94-microns pulsed erbium-YAG radiation on pig skin with those of the pulsed 308-nm UV excimer laser, continuous-wave CO2 laser, electrocautery and cold-knife surgery. Pulsed 2.94-microns radiation led to clean ablation craters and precise cuts with only minimal adjacent tissue damage followed by excellent healing without apparent scarring. These experimental results are consistent with those obtained from first clinical applications in the treatment of epidermal naevi and tattoos. However, since coagulation was insufficient to prevent bleeding and because of low repetition rates provided, the Er-YAG lasers currently available seem as yet of limited value for effective removal of deeper or larger lesions.

Adult↗

PubMed1990

Photoallergic reaction to fluorescein.

A photoallergic reaction to fluorescein was demonstrated in a male diabetic by photopatch and photoprovocation tests. Sensitization was acquired by tonometries using a fluorescein-containing local anesthetic, preceding fluorescein angiography for diagnosis of diabetic retinopathy. Histopathological examination of skin lesions induced in both photopatch and photoprovocation tests confirmed the diagnosis of photoallergic reaction to fluorescein.

Biopsy↗

PubMed1990

[Integrins--new receptor molecules: their significance for the differentiation, regeneration and immune response of the skin].

The integrins are a newly defined family of cell surface receptors. They are involved in the adhesion of cells to the extracellular matrix and to other cells. Integrins and their ligands may be required for complex physiological and pathophysiological events, such as epidermal differentiation, inflammation, immune response, wound healing or tumour progression. Some of the integrin receptor molecules are expressed in a distinct distribution pattern within the skin. Three of them are found selectively in the basal layer of the epidermis, suggesting an important role in establishment of the functional integrity of the dermo-epidermal junction. In the present paper we summarize the available data on the structure and function of integrins and report on the expression of these molecules within the skin and their regulation in cell cultures.

Cell Adhesion↗

PubMed1990

[The mini-punch technic: a method for late removal of traumatic facial tattooing].

Immediate treatment of traumatic facial tattooing using simple brush abrasion usually has good results. In contrast, late removal of incorporated particles mostly leaves scars and is only partially effective. In such cases we tested an excisional technique using minipunches, which was originally designed for the reconstruction of frontal hairlines in grafting to correct male pattern baldness. Although it is so time-consuming, we regard this approach as the method of choice, because it yields good cosmetic results and is easy to carry out, and because there are no adequate alternatives.

Blast Injuries↗

PubMed1989

Identity of GA1, GM1a and GD1b synthase in Golgi vesicles from rat liver.

Synthesis of ganglioside GD1b from ganglioside GD2 was demonstrated using Golgi membranes isolated from rat liver. Competition experiments using gangliosides GA2, GM2 and GD2 as substrates, and as mutual inhibitors for ganglioside galactosyltransferase activity in preparations of Golgi vesicles derived from rat liver, suggested that galactosyl transfer to these three compounds, leading to gangliosides GA1, GM1a and GD1b respectively, is catalyzed by one enzyme. These results strengthen the hypothesis that the main site for the regulation of ganglioside biosynthesis occurs within the reaction sequence LacCer----GA3----GD3----GT3.

Animals↗

PubMed1989

Pulsed Er:YAG- and 308 nm UV-excimer laser: an in vitro and in vivo study of skin-ablative effects.

Using a pulsed XeCl excimer laser (308 nm) and a pulsed Er:YAG laser (2,940 nm), we investigated skin ablation as a function of pulse number, radiant energy, and repetition rate. In vitro analysis of lesions performed in freshly excised human skin were consistent with in vivo results obtained from experiments on pig skin. Pulsed 308 nm laser radiation caused considerable nonspecific thermal tissue injury followed by an inflammatory reaction and impaired healing of lesions in vivo. These findings were especially pronounced with higher repetition rates, which would be required for efficient destruction of larger lesions. On the other hand, the 2.94 microns Er:YAG laser radiation produced clean and precise lesions with only minimal adjacent injury. In vivo skin ablation caused intraoperative bleeding with deeper penetration. The Er:YAG laser offers a promising surgical tool for careful removal of superficial epidermal lesions, if higher repetition rates, and an appropriate laser beam delivery system are available for clinical use.

Animals↗

PubMed1989

Adhesion molecule mapping in normal human skin.

Adhesion molecules are a rapidly growing group of cell surface receptors providing cell-cell and cell-matrix interactions. Their physiological role in tissue homeostasis as well as cellular migration and differentiation is increasingly appreciated. In the present study we have analyzed the expression pattern of most adhesion molecules of the integrin family as well as of adhesion molecules belonging to the immunoglobulin superfamily in normal human skin. We provide evidence that expression of adhesion molecules in the various cutaneous cell systems follows a constant distribution. Moreover, the physiological mononuclear infiltrate of the skin also expresses a variety of adhesion molecules enabeling these cells to migrate or to reside within the skin. Furthermore, our results indicate that intercellular adhesion molecule-1 is not a prerequisite for lymphocyte epidermotropism as frequently stated. Our data provide a rational basis to analyze changing adhesion molecule expression in inflammatory and neoplastic skin diseases.

Adult↗

PubMed1989

Tetraedric and sand-glass crystals in the urine.

Sand-glass and tetraedric crystals often occur in cytologic evaluations of urinary sediments as a secondary finding. The analyses show inflammation and an increase in protein casts as accompanying changes. The basic diseases are primarily renal but unspecific. The analyses of the crystals by laser-ray-technique (LAMMA-analysis) demonstrate calcium in the positive ionic spectrum in both forms. Differences can be registered in the negative ionic spectrum: sand-glasses and small tetraeders contain considerable amounts of phosphate (PO2- and PO3-), while only the larger tetraedric crystals consist of pure calcium oxalate.

Adult↗

PubMed1989

Integrin VLA-3: ultrastructural localization at cell-cell contact sites of human cell cultures.

The integrin VLA-3 is a cell surface receptor, which binds to fibronectin, laminin, collagen type I and VI (Takada, Y., E. A. Wayner, W. G. Carter, and M. E. Hemler. 1988. J. Cell. Biochem. 37:385-393) and is highly expressed in substrate adherent cultures of almost all human cell types. The ligand specificity of VLA-3 and the inhibition of cell adhesion by anti-VLA-3 monoclonal antibodies suggest its involvement in cell-substrate interaction. In normal tissues, VLA-3 is restricted to few cell types, notably the kidney glomeruli and basal cells of the epidermis. In the epidermis, VLA-3 is generally strongly expressed on the entire plasma membrane of basal cells and is not polarized towards the basement membrane (Klein, C. E., C. Cardon-Cardo, R. Soehnchen, R. J. Cote, H. F. Oettgen, M. Eisinger, and L. J. Old. 1987. J. Invest. Dermatol. 89:500-507). Based on this finding we speculated that, in addition to a role of VLA-3 for adhesion of cells to substrate, it could also be relevant for cell-cell interaction. To investigate this, we ultrastructurally localized VLA-3 on the surface of cultured cells by immunoelectron microscopy. In accordance with our concept, we found VLA-3 strongly associated with intercellular contact sites. Interestingly, very little immunoreactivity was detected at the under-surface of cells which had been cultured for 18-32 h. This observation was unexpected but is consistent with previous findings (Kantor, R. R. S., M. J. Mattes, K. D. Lloyd, L. J. Old, and A. P. Albino. 1987. J. Biol. Chem. 262:15158-15165) which suggest that the association of VLA-3 with the basal surface of substrate adherent tumor cells is a late event occurring after days of culture under confluent conditions. However, we cannot formally rule out VLA-3 expression at the undersurface of cells under our experimental conditions, since VLA-3 molecules at this location could be inaccessible for in situ labeling of unfixed cells because of spatial interferences. In conclusion, our results demonstrate the expression of VLA-3 at intercellular contact sites of cultured cells supporting the concept that it may be relevant for intercellular interactions also.

Animals↗

PubMed1989

[Infantile acropustulosis].

Infantile acropustulosis starts in the first few months of life with the recurrent appearance of pruritic intraepidermal pustules containing neutrophils. Predilection sites are the hands and feet. Episodes of pustular eruptions lasting from 8 to 14 days are followed by longer intervals with no symptoms. However, some infants present with skin lesions more widely distributed over the body and with eosinophils as a major constituent of the pustules. In these cases differentiation from other eosinophilic pustular dermatoses of infancy, e.g., the pustular variant of toxic erythema, eosinophilic pustular folliculitis, and transient neonatal pustular melanosis, may become difficult. The etiology of infantile acropustulosis is unknown. The disease clears up spontaneously within the first few years of life. In some cases DADPS therapy has been of benefit.

Acrodermatitis↗

PubMed1989

["Sister Joseph's module"--umbilical metastases of internal tumors].

A 50-year-old man, who was otherwise asymptomatic, presented with an umbilical metastasis of a pancreatic adenocarcinoma. Umbilical metastases ("Sister Joseph's nodule") of internal malignancies are rare. Although they may be the first sign of the underlying malignancy, their appearance is generally correlated with a poor prognosis. Among approximately 400 cases reported in the literature, the most frequent primary tumors were carcinomas of the stomach, ovary, large intestine and pancreas.

Adenocarcinoma↗

PubMed1988

[Phlebology--current therapeutic aspects from the dermatologic viewpoint].

Modern diagnostic procedures in phlebology have not only enhanced our understanding of the pathophysiology of the venous system; they also provide considerable help in the planning and evaluation of phlebotherapeutical measures. Thus the dermatologist involved in phlebology has become able to proceed in a differentiated way regarding the treatment of primary varicosis as well as preventive measures and therapy of chronic venous insufficiency. The treatment includes both conservative and surgical procedures and is based on experiences in phlebology, allergology, topical dermatotherapy, and dermatosurgery.

Humans↗