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Biomedical subjects

A Maier

Publications and source records attributed to A Maier.

At least 19 recordsLinked to original sources
PubMed2003

Pneumopericardium due to intrapericardial perforation of a gastric ulcer.

A 88-year-old male patient presented with fever, singultus and retrosternal pain. After 8 days of antibiotic therapy not resulting in clinical improvement, he suddenly developed a pneumopericardium. Contrast swallow and endoscopy showed intrapericardial perforation of a benign gastric ulcer. Excision of the ulcer and suturing of both the stomach and the diaphragm as well as lavage of the pericardium were done over a left thoracotomy. The patient recovered uneventfully.

Aged↗
PubMed2003

Penetration of fosfomycin into inflammatory lesions in patients with cellulitis or diabetic foot syndrome.

We investigated the distribution of the broad-spectrum antibiotic fosfomycin in infected soft tissue of patients with uncomplicated cellulitis of the lower extremities or diabetic foot infection using in vivo microdialysis. Our findings suggest that fosfomycin exhibits good and similar penetration into the fluid in the interstitial space in inflamed and noninflamed soft tissue in patients.

Area Under Curve↗
PubMed2003

Collagenase cleavage of type I collagen is essential for both basal and parathyroid hormone (PTH)/PTH-related peptide receptor-induced osteoclast activation and has differential effects on discrete bone compartments.

Expression of a constitutively active PTH/PTHrP receptor in cells of osteoblast lineage in vivo (CL2+) causes increases in trabecular bone volume and trabecular bone formation and, conversely, a decrease in the periosteal mineral apposition rate. Collagenase-3 (matrix metalloprotease-13) is a downstream target of PTH action. To investigate the relevance of collagenase cleavage of type I collagen for the CL2+ bone phenotype, we bred CL2+ animals with mice carrying a mutated col1 alpha 1 gene that encodes a protein resistant to digestion by collagenase-3 and other collagenases (rr). Adult tibias and parietal bones from 4-wk-old double-mutant animals (CL2+/rr) and from control littermates were analyzed. Trabecular bone volume was higher in CL2+/rr than in CL2+ mice. This increase occurred despite a modest reduction in bone formation rate, which was, however, still significantly higher that in wild-type littermates, and therefore must reflect decreased bone resorption in rr mice. Osteoclast number was increased in CL2+/rr animals compared with either wild-type or CL2+ mice, suggesting that collagenase-dependent collagen cleavage affected osteoclast function rather than osteoclast number and/or differentiation. Interestingly, the periosteal mineral apposition rate was similar in CL2+/rr and CL2+ animals and was significantly lower than that in wild-type animals. Our study provides evidence that collagenase activity is important for both basal and PTH/PTHrP receptor-dependent osteoclast activation. Furthermore, it indicates that a mild impairment of osteoclast activity is still compatible with increased osteoblast function. Lastly, it supports the hypothesis that collagenases can be a downstream effector of PTH/PTHrP receptor action in trabecular bone, but not in periosteum.

Animals↗
PubMed2002

Stress-induced hormonal and mood responses in scuba divers: a field study.

The majority of injuries in scuba-divers are attributable to inappropriate behavior under stressful diving conditions, predominantly involving panic reactions emerging from elevated levels of anxiety. Divers with an elevated level of anxiety and poor coping are at higher risk of developing panic reactions than those possessing more adequate stress-coping-mechanisms. In the comparison of two extreme groups of seven divers each with opposite stress coping strategies, prolactin was found to be a hormonal marker with a significant increase in the sub-group of the stress-controllers. This hormonal response was observed in a recreational and a stressful dive, and in the latter with a more distinct elevation. Along with the self-reported emotional conditions under immersion, these data suggest that an increased prolactin level reflects a state of elevated physical and mental activation and vigilance. Facing a stressful situation subjects with more emotional concern and the tendency to surrender react by "blunted responses" and show significantly lower elevations of the prolactin levels in contrast to subjects with the very opposite psychological features. The other observed somatic parameters (epinephrine, norepinephrine) showed significant increases during and after dives (with the exception of saliva cortisol), however without any significant group difference.

Adolescent↗
PubMed2002

Genetic polymorphisms in assessing interindividual variability in delivered dose.

Increasing sophistication in methods used to account for human variability in susceptibility to toxicants has been one of the success stories in the continuing evolution of risk assessment science. Genetic polymorphisms have been suggested as an important contributor to overall human variability. Recently, data on polymorphisms in metabolic enzymes have been integrated with physiologically based pharmacokinetic (PBPK) modeling as an approach to determining the resulting overall variability. We present an analysis of the potential contribution of polymorphisms in enzymes modulating the disposition of four diverse compounds: methylene chloride, warfarin, parathion, and dichloroacetic acid. Through these case studies, we identify key uncertainties likely to be encountered in the use of polymorphism data and highlight potential simplifying assumptions that might be required to test the hypothesis that genetic factors are a substantive source of human variability in susceptibility to environmental toxicants. These uncertainties include (1) the relative contribution of multiple enzyme systems, (2) the extent of induction/inhibition through coexposure, (3) allelic frequencies of major ethnic groups, (4) the absence of chemical-specific data on the kinetic parameters for the different allelic forms of key enzymes, (5) large numbers of low-frequency alleles, and (6) uncertainty regarding differences between in vitro and in vivo kinetic data. Our effort sets the stage for the acquisition of critical data and further integration of polymorphism data with PBPK modeling as a means to quantitate population variability.

Animals↗
PubMed2002

Management of iatrogenous esophagus perforation.

OBJECTIVES: The management of patients with iatrogenous, instrumentally caused esophageal disruptions is still a controversially discussed challenge for any physician. We reviewed indications, morbidity, and mortality of esophagectomy compared to less aggressive treatment schemes in the light of our single-unit experience. PATIENTS AND METHODS: We reviewed the cases of 38 consecutive patients suffering from iatrogenous esophageal disruption treated within the last 10 years at the University Medical School Graz. RESULTS: Severe sepsis was diagnosed in seventeen patients; fourteen of the seventeen patients were treated by esophagectomy followed by primary or secondary reconstruction at a mortality rate of 28.6 % (four of fourteen patients). All fourteen patients thus treated had major preexisting esophageal pathologies. In three of the total seventeen cases reviewed, conservative treatment modalities were used. The mortality rate in the non-septic group treated by direct suturing (n = 21) was 4.8 % (one of twenty-one patients). Major preexisting esophageal pathology was present in thirteen. The overall mortality was 13.2 % (five of thirty-eight patients). CONCLUSION: The strategy of primary repair for iatrogenous esophageal injury should only be adopted in patients with minor or without intrinsic esophageal disease, and in the absence of severe sepsis suggesting mediastinitis. Severe sepsis following iatrogenous esophageal trauma should prompt the decision for esophagectomy where anatomically and/or oncologically possible.

Esophageal Diseases↗
PubMed2002

[Virtual multislice computed tomographic colonoscopy].

Virtual colonoscopy or computed tomographic (CT) colonography is a rapidly evolving technique for imaging the entire colon and detection of colorectal polyps. It uses standard helical computed tomography images of the colon and advanced imaging software to produce reformatted two- and three-dimensional views of the entire colorectum. Multi-detector row helical computed tomography has several technical advantages over single-detector row computed tomographic, including faster imaging times with the acquisition of thinner sections. The improved speed and spatial resolution of multislice computed tomography promises an increase of sensitivity and specificity, especially for the detection of colorectal lesions.

Colonic Polyps↗
PubMed2001

Size-dependent melting of self-assembled indium nanostructures.

We have measured the melting temperature of nanoscale indium islands on a WSe(2) substrate using perturbed angular correlations combined with scanning tunneling microscopy. The indium islands are self-assembled nanostructures whose diameter can vary between about 5 and 100 nm, depending on deposition conditions. The melting point decreases due to surface energies as the islands get smaller. This decrease depends on the faceting of the crystalline nanostructures and interactions between the islands and the substrate.

Journal Article↗
PubMed2001

Sources of variation in patient response to radiation treatment.

PURPOSE: To investigate sources of variation in radiosensitivity displayed by cancer patients and blood donors using the leukocyte apoptosis assay. METHODS AND MATERIALS: Probes were obtained from 105 healthy blood donors, 48 cancer patients displaying normal sensitivity to radiotherapy, 12 cancer patients displaying hypersensitivity to radiotherapy, 12 Ataxia telangiectasia blood donors, and 4 additional individuals with genetic diseases of potentially modified radiosensitivity; 2 neurofibromatosis (NF) donors, a Nijmegen breakage syndrome (NBS) donor, and an Immunodeficiency, Chromosome fragility, Facial anomaly syndrome (ICF) donor. Heparinized blood was diluted in medium, irradiated, and left to incubate for 48 h. CD4 and CD8 T-lymphocyte DNA was stained with propidium iodide and the cells were analyzed by flow cytometry. RESULTS: Radiation-induced apoptosis depended on age and cell type. Cohorts of hypersensitive cancer patients, NBS and AT donors displayed compromised apoptotic response. An asymmetric apoptotic response of T-lymphocytes was observed in an ICF donor and a cryptic hypersensitivity donor. Two NF donors displayed no abnormal sensitivity to radiotherapy but compromised apoptotic T-cell response to X-rays. CONCLUSION: Our studies reveal 4 physiologic sources of variation in radiation response-2 are genetic: cryptic hypersensitivity and hereditary disease, and 2 are epigenetic: cell type and donor age. They emphasize the important role of proteins involved in the recognition and repair of DNA double-strand breaks in determining the response of individuals to radiotherapy.

Adolescent↗
PubMed2001

Targeted disruption of Col11a2 produces a mild cartilage phenotype in transgenic mice: comparison with the human disorder otospondylomegaepiphyseal dysplasia (OSMED).

Transgenic mice were prepared by homologous recombination with a Col11a2 targeting gene in which an inverted neomycin-resistant gene was inserted between restriction sites in exons 27 and 28. The targeted allele was transcribed in shortened mRNAs, which could be detected by Northern blotting. However, translation of the full-length Col11a2 chain was unable to occur because of the presence of premature termination codons within the inverted neomycin-resistant gene. Analysis of pepsin-resistant collagen chains from rib cartilage of homozygous mice demonstrated the lack of synthesis of intact alpha2(XI) chains. However, pepsin-resistant collagen chains of either alpha1(XI) or alpha1(V) were still detected on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Therefore, alpha2(XI) chains are not essential for the assembly of some molecular forms of triple-helical type V/XI collagen. The phenotype was milder than in the cho/cho mouse in which, as the result of mutation, translation of the full-length alpha1(XI) chain fails to occur and the mice die at birth (Li et al., 1995). Homozygous mice without expression of an alpha2(XI) chain had a smaller body size, receding snouts, and deafness. Nasal bones in the homozygous transgenic mice were specifically shorter and dimpled on their external surfaces. Chondrocytes in growth plates of all long bones were markedly disorganized and failed to align in columns. Analysis of growth plates from transgenic mice by in situ hybridization showed expression of alpha1(II) and alpha1(XI) but not of alpha1(I) or alpha1(V) which, in contrast, were expressed in the developing bone and in the bone collar. Expression of alpha1(X) specifically in the hypertrophic cartilage was observed in normal and transgenic mice. No obvious osteoarthritis was observed throughout the life of homozygous mice up to 1 year of age, although minor morphologic anomalies in the articular cartilages were discernible. The mild phenotype is consistent with similar mutations in the COL11A2 gene seen in patients with nonocular Stickler syndrome and some patients with otospondylomegaepiphyseal dysplasia (OSMED), as well as in patients with a nonsyndromic form of deafness called DFNA13.

Animals↗
PubMed2001

Acute effects of combined photodynamic therapy and hyperbaric oxygenation in lung cancer--a clinical pilot study.

BACKGROUND AND OBJECTIVE: Photodynamic tumor therapy (PDT) is based upon a photochemical reaction that is limited by the availability of molecular oxygen in the target tissue. The use of hyperbaric oxygenation (HBO) increases the amount of oxygen available for the process may thereby enhance the efficacy of PDT. We investigated the acute effects on tumor stenosis after combined PDT/HBO. PATIENTS AND METHODS: Thirty patients (22 males, 8 females, mean age: 68.8 years; range: 44-78 years) with inoperable non-small cell bronchogenic carcinoma and endobronchial stenosis were studied prospectively. Photosensitization was carried out using a hematoporphyrin-derivative 2 mg/kg BW 48 hours prior to PDT. The light dose was calculated as 300 J/cm fiber tip. The assessment of outcome 1 and 4 weeks after PDT/HBO was performed by endoscopy, chest X-ray, spirometry, laboratory parameters, subjective report of dyspnea, and Karnofsky performance status. RESULTS: At one and four weeks after the treatment, the patients felt a significant improvement of dyspnea and hemoptysis along with an objective subsiding of poststenotic pneumonia, though spirometric parameters revealed no significant difference. A significant reduction of tumor stenosis (P < 0.05) and an improvement of the Karnofsky performance status (P < 0.05) were documented 1 and 4 weeks after PDT/HBO. No therapy related complications were observed. CONCLUSIONS: Although the small number of patients does not allow to draw definitive conclusions to be drawn, the results suggests that combined PDT/HBO represents a new, safe, and technically feasible approach. It enables efficient and rapid reduction of the endoluminal tumor load and helps conditioning the patient for further treatment procedures.

Adult↗
PubMed2001

Does new photosensitizer improve photodynamic therapy in advanced esophageal carcinoma?

BACKGROUND AND OBJECTIVE: Polyhematoporphyrin (Photosan) as sensitizers for photodynamic therapy (PDT) in advanced esophageal cancer carry the risk of prolonged photosensitivity of the skin. New sensitizers such as 5-aminolaevulinic acid (ALA) with low rates of skin phototoxicity appear to be promising alternatives. The aim of this study was to evaluate the efficacy of ALA compared to Photosan for PDT in advanced esophageal carcinoma regarding phototoxicity of the skin, reduction of dysphagia, tumor stenosis, and tumor length and Karnovsky performance status. STUDY DESIGN/MATERIALS AND METHODS: After diagnostic work-up, photosensitization was done in 22 patients with ALA (60 mg/kg body weight, oral, 6-8 hours prior to PDT) and in 27 patients with Photosan (2 mg/kg body weight, i.v., 48 hours before PDT). The light dose was calculated as 300 J/cm fibre tip. Light at 630 nm was applied using a pumped dye laser. In both groups, additional hyperbaric oxygenation was applied at a level of 2 absolute atmospheric pressure. RESULTS: Improvement regarding dysphagia, stenosis diameter, and tumor length could be obtained in both treatment arms with a significant difference in favour of the Photosan-group, P = 0.02; P = 0.0000; and P = 0.000014, respectively. The Karnovsky performance status also improved in both groups and showed no significant difference (P = 0.12). The median survival time for the ALA-group was 8.0 months, compared with 9.0 months for the Photosan group. No sunburn or other major treatment related complication occurred in both treatment arms. Thirty-day mortality was 0%. CONCLUSION: Despite the limitations of a non-randomized study, photosensitzation with Photosan seems to be more effective in PDT of advanced esophageal carcinoma compared to ALA.

Adenocarcinoma↗
PubMed2001

Photosensitization with hematoporphyrin derivative compared to 5-aminolaevulinic acid for photodynamic therapy of esophageal carcinoma.

BACKGROUND: Hematoporphyrin derivatives (HpD) as sensitizers for photodynamic therapy (PDT) in advanced esophageal cancer carry the risk of prolonged photosensitivity of the skin. New sensitizers such as 5-aminolaevulinic acid (ALA) with low rates of skin phototoxicity appear to be promising alternatives. The aim of this study was to evaluate the efficacy of ALA compared with HpD for PDT in advanced esophageal carcinoma regarding phototoxicity of the skin, reduction of dysphagia, tumor stenosis and length, and Karnovsky performance status. METHODS: After diagnostic workup, photosensitization was done in 22 patients with ALA (60 mg/kg body weight, oral, 6 to 8 hours before PDT) and in 27 patients with a hematoporphyrin derivative (2 mg/kg body weight, intravenously, 48 hours before PDT). The light dose was calculated as 300 J/cm fiber tip. Light at 630 nm was applied using a pumped dye laser. In both groups, additional hyperbaric oxygenation was applied at a level of 2 absolute atmospheric pressure. RESULTS: Improvement regarding dysphagia, stenosis diameter, and tumor length could be obtained in both treatment arms with a significant difference in favor of the HpD group (p = 0.02; p = 0.0000; and p = 0.000014, respectively). A questionnaire of patients in the HpD group confirmed that the ability of swallowing a meal was superior compared with the discomfort from limitation to sun exposure. No sunburn or other major treatment-related complication occurred in both treatment arms. CONCLUSIONS: Despite the limitations of a nonrandomized study, photosensitzation with HpD seems to be more effective in PDT of advanced esophageal carcinoma compared with ALA.

Adenocarcinoma↗
PubMed2001

Photodynamic therapy enhanced by hyperbaric oxygen in acute endoluminal palliation of malignant bronchial stenosis (clinical pilot study in 40 patients).

OBJECTIVES: Photodynamic tumor therapy (PDT) is based upon a photochemical reaction that is limited by the availability of molecular oxygen in the target tissue. The use of hyperbaric oxygenation (HBO) increases the amount of oxygen available for the process may thereby enhance the efficacy of PDT. We proved in a prospective, non-randomized clinical pilot study the acute effects on malignant bronchial stenosis and the technical feasibility of combined PDT/HBO. METHODS: Forty patients (29 males, 11 females, mean age: 64.3 years; range 39-82 years) with inoperable, advanced malignant bronchial tumor stenosis were studied prospectively. Photosensitization was carried out using a hematoporphyrin-derivative 2 mg/kg bw 48 h prior to PDT. The light dose was calculated as 300 J/cm fiber tip. The assessment of outcome 1 and 4 weeks after PDT/HBO was done by endoscopy, chest X-ray, spirometry, laboratory parameters, subjective report of dyspnea and Karnofsky performance status. RESULTS: At 1 and 4 weeks after the treatment the patients felt a significant improvement of dyspnea and hemoptysis alongside with an objective subsiding of poststenotic pneumonia, though spirometric parameters revealed no significant difference. A significant reduction of tumor stenosis (P<0.05) and an improvement of the Karnofsky performance status (P<0.05) were documented 1 and 4 weeks after PDT/HBO. No therapy related complications were observed. CONCLUSION: Although the small number of patients does not allow to draw definitive conclusions, the results suggest that combined PDT/HBO represents a new, safe and technically feasible approach. It enables efficient and rapid reduction of the endoluminal tumor load and helps conditioning the patient for further treatment procedures.

Adenocarcinoma↗
PubMed2001

Indications for surgery in tracheobronchial ruptures.

OBJECTIVE: Ruptures of the tracheobronchial tree present a life-threatening situation. Nevertheless, therapy is still controversial. Though conservative treatment by antibiotics and intubation with the cuff inflated distal to the tear is favored by some authors, surgical repair is unavoidable in many cases. METHODS: We present a series of 31 patients (mean age 43.6 years, range 8--72 years) with iatrogenous or post-traumatic tracheobronchial ruptures treated since 1975. Fifteen ruptures were longitudinal tears of the trachea, not extending lower than a distance of 3 cm from the bifurcation, 11 involved the bifurcation and/or the main bronchi. The total length of the longitudinal tears ranged from 2 to 12 cm, five were transverse near complete abruptions of the trachea or main bronchi. Involvement of the full thickness of the wall with free view into the pleural space or to the esophageal wall was present in 29 cases. Twenty-nine out of the 31 patients underwent surgical repair and two were treated conservatively. The length and depth of the lesion, the degree of subcutaneous emphysema, pneumothorax and/or pneumomediastinum as well as clinical signs suggesting incipient mediastinitis were considered when making the decision for surgery. RESULTS: Twenty-five out of the 29 patients experienced an uneventful recovery. Four patients died of sepsis unrelated to the tracheobronchial trauma. One of the two patients who underwent conservative therapy also recovered uneventfully. The other one died because of multi-organ failure due to underlying myocardial infarction. CONCLUSIONS: Conveniently localized short lacerations, especially if they do not involve the whole thickness of the tracheal wall, can be treated with antibiotics and intubation with the cuff inflated distal to the tear, avoiding high intra-bronchial pressures also after eventual extubation. In all other cases surgical repair is to be preferred.

Adolescent↗
PubMed2001

Successful endoscopical sealing of malignant esophageotracheal fistulae by using a covered self-expandable stenting system.

OBJECTIVE: Any treatment of tracheo-esophageal fistulae in end-stage malignant stenosis of the esophagus must be weighed against associated morbidity and mortality. In a prospective study we investigated benefits and risks of the use of one type of coated, self-expandable stent. PATIENTS AND METHODS: We treated four male and two female patients, (mean age 68.3 years, range: 38-90 years), with malignant esophago-tracheal fistula non-resectable due to advanced tumour stage and/or functional reasons. All were in a poor general condition suffering from aspiration pneumonia and malnutrition. Four out of the six patients had had one or multiple extra- or endoluminal palliative treatments at a mean interval of 191 days (range: 7 days-15 ms) since the last intervention. The fistulae were sealed by using a covered, self-expandable stent (ULTRAFLEX esophageal stent system, Microinvasive, Boston Scientific Corporation, Boston, MA). RESULTS: Stenting did not cause any technical problems and all fistulae were successfully sealed in a one-step procedure. The median hospital stay was 4.6 days (range: 3-9 days). Except for one late stent induced recurrent fistula treated by re-stenting and tracheostomy, we did not observe any stent associated complications. Five patients died of tumour generalization. The median survival of the patients who died was 78 days (range: 35-129 days). One patient is alive and well at 120 days after stenting. CONCLUSION: In spite of the small number of patients the results suggest that this type of stent represents a safe and efficient approach for palliative endoscopic treatment of this high risk group. Local pretreatment does not preclude the successful use of the self-expandable coated stent.

Adenocarcinoma↗
PubMed2001

Tetranectin in slow intra- and extrafusal chicken muscle fibers.

Tetranectin is a C-type lectin that occurs in the mammalian musculoskeletal system. In the present report we describe the first studies on an avian tetranectin. A full-length chicken tetranectin cDNA was isolated. Comparison of the deduced amino acid sequence of chicken tetranectin with mouse and human tetranectin showed an identity of 67 and 68%, respectively. Northern blot analysis demonstrated broad expression of chicken tetranectin mRNA, which was first detected on embryonic day 4. Tetranectin protein was detected in chicken serum and egg yolk. Since muscle is one of few tissues in which tetranectin protein is retained, we examined the distribution of tetranectin in various muscle types in chicken. Myofibers strongly positive for tetranectin were observed in several muscles including m. tibialis ant. and m. sartorius (from embryonic day 10 to adult). Using antibodies to fast and slow myosin heavy chains (MHC) and double immunostaining techniques, we found that tetranectin was restricted to slow (type I) muscle fibers. Similarly only slow intrafusal fibers accumulated tetranectin. The pattern of immunostaining in chickens differs markedly from that seen in mouse muscles, indicating that tetranectin performs a role in muscle that is not associated with a hitherto recognized muscle type or function.

Adaptation, Physiological↗