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Biomedical subjects

A Klotz

Publications and source records attributed to A Klotz.

13 recordsLinked to original sources
PubMed2003

Feasibility of surgical technique and evaluation of postoperative quality of life after laparoscopic treatment of intrathoracic stomach.

BACKGROUND: Because of the risk of life-threatening complications, the discovery of a complete intrathoracic stomach demands urgent surgery with the aim of repositioning the stomach and gastropexy, and secondarily, to improve life quality. In this study the feasibility of surgical technique and postoperative quality of life after laparoscopic treatment of complete intrathoracic stomach has been evaluated. METHODS: From June 1999 to December 2001 16 patients with an intrathoracic stomach (hiatus hernia Types IIB and III) were treated by laparoscopic techniques, including the repositioning of the stomach, hemi-fundoplication and anterior gastropexy. During the postoperative follow-up the recurrence rate and quality of life (Eypasch index) were evaluated. RESULTS: All operations were performed laparoscopically without conversion, with a mean operating time of 155 min. Pleural injuries occurred in 31% of patients and pleural effusions in 38%, which required puncture in three cases. Complete follow-up showed no recurrences at a median of 14 months. The median quality of life index was 84.6 preoperatively and had significantly improved to 117.8 after the operation. CONCLUSION: Laparoscopic access for the treatment of intrathoracic stomach represents a minimally invasive and safe treatment option for complete intrathoracic stomach, with a low level of perioperative morbidity and significant improvement in quality of life.

Adult↗
PubMed2003

Skin cleansers for occupational use: testing the skin compatibility of different formulations.

OBJECTIVES: Skin-compatible hand cleansing is crucial for the prevention of occupational dermatitis. In this article we give an overview of skin-cleansing products and their ingredients and investigate whether solvents or abrasives could be avoided in cleansers for severely soiled skin. METHODS: Comparison of skin compatibility, cleansing power and effectiveness of different formulations of skin cleansers was performed via Duhring chamber tests [visual score, trans-epidermal water loss (TEWL)] and standard hand-wash tests. RESULTS: The results show that, dependent on the grade of contamination, a range of skin cleansers that allow adequate skin cleansing, is necessary. Solvents could be avoided, by the use of powerful cleansing systems based on tenside/oil mixtures. Only for special contaminations may solvents be useful. Powerful cleansing activity could be performed without abrasives. CONCLUSIONS: The worker must be able to choose the skin cleanser that is adequate for the contamination that is present. Therefore, information and education of the workers are crucial for skin-compatible skin cleansing.

Anti-Infective Agents, Local↗
PubMed2003

Occupational skin-protection products--a review.

Skin-protection products are used in the occupational field to protect the skin against hazards from the workplace. They are only to be used for non-toxic, non-cancerogenous and non-sensitizing low-grade irritants such as water, detergents, and cutting fluids and cannot replace other protective measures such as gloves. The recommendation of products mainly focuses on the physico-chemical properties of the irritant and the protective cream. More in vivo studies and intervention studies are needed to prove the efficacy of skin-protection products under real-life conditions.

Dermatitis, Occupational↗
PubMed2001

Master-slave synchronization in chaotic discrete-time oscillators.

In this paper, we study a simple discrete-time neural oscillator model that, in certain parameter regimes, exhibits periodic or chaotic dynamics. The present model with intrinsically chaotic dynamics is capable of spatiotemporal information processing: in response to constant external stimulation, the oscillator can switch into different chaotic states restricted to distinct parts of the phase space. Of particular interest is the processing of time-dependent input in a master-slave configuration of two coupled oscillators. Here, the response of an oscillator is studied by driving it with the signal of the other. Following the input, the response system adapts to the state of the drive. For a chaotic drive, we can observe generalized synchronization. The onset of adaptation to the drive state by the response is accompanied by on-off intermittency resulting in irregular bursting behavior.

Journal Article↗
PubMed1999

Polyglutamylation of atlantic cod tubulin: immunochemical localization and possible role in pigment granule transport.

In higher organisms, there is a large variety of tubulin isoforms, due to multiple tubulin genes and extensive post-translational modification. The properties of microtubules may be modulated by their tubulin isoform composition. Polyglutamylation is a post-translational modification that is thought to influence binding of both structural microtubule associated proteins (MAPs) and mechano-chemical motors to tubulin. The present study investigates the role of tubulin polyglutamylation in a vesicle transporting system, cod (Gadus morhua) melanophores. We did this by microinjecting an antibody against polyglutamylated tubulin into these cells. To put our results into perspective, and to be able to judge their universal application, we characterized cod tubulin polyglutamylation by Western blotting technique, and compared it to what is known from mammals. We found high levels of polyglutamylation in tissues and cell types whose functions are highly dependent on interactions between microtubules and motor proteins. Microinjection of the anti-polyglutamylation antibody GT335 into cultured melanophores interfered with pigment granule dispersion, while dynein-dependent aggregation was unaffected. Additional experiments showed that GT335-injected cells were able to aggregate pigment even when actin filaments were depolymerized, indicating that the maintained ability of pigment aggregation in these cells was indeed microtubule-based and did not depend upon actin filaments. The results indicate that dynein and the kinesin-like dispersing motor protein in cod melanophores bind to tubulin on slightly different sites, and perhaps depend differentially on polyglutamylation for their interaction with microtubules. The binding site of the dispersing motor may bind directly to the polyglutamate chain, or more closely than dynein.

Animals↗
PubMed1999

Transepithelial transport processes at the intestinal mucosa in inflammatory bowel disease.

Crohn's disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases (IBD) of unknown etiology. Oral absorption studies have shown an increased intestinal permeability for various sugar molecules in patients with IBD and their healthy relatives as a possible pathogenetic factor. However, the various transport pathways through the mucosal barrier have not yet been examined. This study therefore investigated whether antigens pass the epithelial barrier by a transcellular or a paracellular pathway. Mucosa of freshly resected specimens from CD (n = 10) or UC (n = 10) patients was investigated by immunoelectron microscopy and compared with healthy mucosa. Epithelial transport was studied with the antigens ovalbumin and horseradish peroxidase after defined incubation. Labeling density of subunit c of ATP synthetase was determined in mitochondria of enterocytes of all specimens. In all specimens epithelial transport of OVA and HRP was principally transcellular through enterocytes with normal ultrastructure, although some tight junctions in CD and UC were dilated. Antigens were transported within vesicles to the basolateral membrane 2.5 min after incubation. The level of enterocytes with electron-lucent cytoplasm containing a high amount of antigens was higher in CD and UC than in healthy mucosa, depending on the grade of inflammation. ATP synthetase was significantly decreased in electron-lucent cytoplasm of CD and UC to normal ultrastructure of healthy mucosa. Our study shows that ovalbumin and horseradish peroxidase taken up by the apical membrane reach the paracellular space by vesicular transport in healthy and IBD enterocytes within a few minutes. Transcellular pathway is affected in both CD and UC, which is indicated by a high level of antigens within the cytosol. We speculate that increased intestinal permeability in IBD results substantially from enhanced transcellular transport.

Adult↗
PubMed1999

A small-size neural network for computing with strange attractors.

A small-size model for a chaotic neural network is proposed using strange attractors for computation. This network has a chaotic ground state and is capable of responding to external stimuli by constraining the network dynamics to specific parts of the ground state attractor. For parameter optimization, bifurcation diagrams are evaluated.

Journal Article↗
PubMed1978

NADP-specific glutamate dehydrogenase in Metridium senile (L.).

1. An NADP-specific glutamate dehydrogenase (E.C. 1.4.1.4) of mitochondrial origin has been detected in M. senile, a sea anemone. 2. Substrate specificity and starch gel electrophoresis experiments indicated an absence of the NAD(P) glutamate dehydrogenase (E.C. 1.4.1.3). 3. This NADP specific GDH activity appears to be the sole GDH activity in species of the animal phylum Coelenterata.

Animals↗
PubMedDate not supplied

Using skin models to assess the effects of a protection cream on skin barrier function.

BACKGROUND: There is a basic necessity to understand the mechanisms of the protective effects of emulsions. This would promote the development of protective cosmetics and therefore improve the prevention and treatment of occupational skin diseases. However, for such studies, no reliable skin model is available. OBJECTIVE: An in vitro skin model test was developed to evaluate the protective mechanism of cosmetic ingredients. METHODS: The efficacy of three products was assessed by an in vivo test (Repetitive Occlusive Irritation Test) and then 3-dimensional skin model tests were carried out. RESULTS: In vivo test results demonstrate that the best protection against sodium dodecyl sulphate is offered by a multiple emulsion. In the case of a skin model test, sodium dodecyl sulphate led to cell damage, an increase in pro-inflammatory markers and some barrier lipids. The multiple emulsion increased the content of skin lipids, without inducing irritation or cell death. CONCLUSION: Skin models react similarly to sodium dodecyl sulphate compared to human skin and therefore they are suitable to study barrier repair after sodium dodecyl sulphate damage. It is likely that the superior protective effect of the multiple emulsion in vivo is based on the increased amount of skin barrier lipids.

Administration, Cutaneous↗