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Biomedical subjects

B Schmidt

Publications and source records attributed to B Schmidt.

At least 19 recordsLinked to original sources
PubMed2006

Antithrombin for respiratory distress syndrome in preterm infants.

BACKGROUND: Acquired Antithrombin (AT) deficiency is a common and prognostically important finding in sick preterm infants with respiratory distress syndrome (RDS). It has been hypothesised that AT concentrate may improve clinical outcomes in preterm infants with RDS. OBJECTIVES: To determine whether the administration of AT concentrate decreases mortality in preterm infants with RDS compared with placebo or no treatment. SEARCH STRATEGY: An electronic literature search in the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE in August 2006 was performed. No language restriction was applied. References from identified studies were cross-checked for possible additional studies. Experts in the field and pharmaceutical companies were contacted for unpublished data. Abstracts of the American Society of Pediatric Research and European Society of Pediatric Research meetings (1983-2005) were searched and authors of relevant studies were contacted to obtain additional information. SELECTION CRITERIA: Randomized controlled trials comparing any dose and duration of AT therapy with placebo or no treatment in preterm infants with RDS. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data from included studies regarding mortality, intraventricular hemorrhage, mechanical ventilation, and other reported events in the clinical course of the patients. Data for similar outcomes were combined where appropriate, using a fixed-effects model in MetaView 4.2 (Update Software). MAIN RESULTS: Two trials consisting of 182 preterm infants, fulfilled the inclusion criteria. Mean gestational age of patients included was 28 weeks. In one trial, patients had to be intubated and ventilated for RDS to be eligible for the study. In the other trial, RDS was not mentioned as an inclusion criteria, however the vast majority of infants in the study received surfactant. No individual trial showed a significant difference in mortality. One of the trials was stopped early because of an increase in deaths in the AT group. The pooled analysis for mortality within the first week of life showed a typical relative risk of 2.67 (95% CI 0.72-9.83) in favour of the control group. Only the trial that was stopped early followed the infants long enough to report neonatal mortality. This trial reported 7 deaths (11.5%) in the AT group and two deaths (3.3%) in the placebo group within 28 days of life. Secondary outcomes included days of mechanical ventilation and supplemental oxygen which were only reported in 1 trial. Both outcomes were in favour of the control group and statistically significant (p < 0.05). AUTHORS' CONCLUSIONS: Preterm infants with RDS are unlikely to benefit from AT treatment and may be harmed.

Anticoagulants↗
PubMed2006

Circulating nucleic acids (CNAs) and cancer--a survey.

It has been known for decades that it is possible to detect small amounts of extracellular nucleic acids in plasma and serum of healthy and diseased human beings. The unequivocal proof that part of these circulating nucleic acids (CNAs) is of tumor origin, initiated a surge of studies which confirmed and extended the original observations. In the past few years many experiments showed that tumor-associated alterations can be detected at the DNA and RNA level. At the DNA level the detection of point mutations, microsatellite alterations, chromosomal alterations, i.e. inversion and deletion, and hypermethylation of promoter sequences were demonstrated. At the RNA level the overexpression of tumor-associated genes was shown. These observations laid the foundation for the development of assays for an early detection of cancer as well as for other clinical means.

Biomarkers, Tumor↗
PubMed2006

Educating to improve population health outcomes in chronic disease: an innovative workforce initiative across remote, rural and Indigenous communities in northern Australia.

INTRODUCTION: Like Indigenous populations in other countries, an epidemic of chronic disease has swept across Australia's Indigenous communities in the past decade. The Northern Territory and Queensland health departments initiated preventable chronic disease strategies in 1999 and 2001, respectively. Yet finding innovative ways to translate this to the health workforce was challenging. Through support from the Australian Government, three universities, two health departments and two Indigenous organisations worked in partnership to improve workforce capacity in remote and rural communities through innovative education. METHODS: The methods included: (i) a training needs analysis consisting of 76 semi-structured interviews with key informants, and 35 surveys of remote staff; (ii) a literature and resource review; (iii) the development of a curriculum framework using: the existing competencies and standards across the health disciplines; the identified workforce needs; and what the workforce can impact upon; (iv) a multidisciplinary workshop with 35 educators across northern Australia that resulted in the basis for agreement of the final curriculum content and framework; (v) the development of a chronic disease self-assessment tool that was piloted with remote health staff; (vi) an assisted integration process for key stakeholders. An evaluation framework was also developed, as a separate project, in conjunction with the project partners during this time. RESULTS: This project identified that a paradigm shift is required in the way in which we educate the entire health workforce to deal effectively with the impact of chronic disease across remote, rural and Indigenous populations. In particular a need was found to educate the educators in the chronic care model and in using a population health approach. The training needs analysis identified very little difference between the education and training needs across the rural and remote health disciplines; it was perceived that they managed chronic disease fairly well yet found prevention and early detection to be at the 'hard end'. The main barriers identified were the demands of acute care over chronic disease management, compounded by high workforce turnover in remote areas. The curriculum framework, in particular the domains of remote practice, is being used by several Australian universities, health departments and non-government organisations in adapting their existing or new education programs. The self-assessment tool was based on the curriculum outcomes and was piloted in 2005 and found to be very useful for pre- and post-training purposes and as a discussion starter for all disciplines and groups. CONCLUSIONS: A practical curriculum framework now exists to integrate a population health approach for the prevention and early detection of chronic disease when educating the primary healthcare workforce. It is relevant to all health disciplines and is flexible in that it can be adapted, or adopted, depending on the educational needs of the disciplinary group. It is being imbedded into numerous undergraduate, postgraduate, and professional development programs in Australia. It includes: the core learning outcomes expected of any workforce, resources, and a self-assessment tool in chronic disease. These tools are assisting educators in the required paradigm shift required of the workforce to alter the single disease based practice model towards a comprehensive and integrated population based approach required for the workforce in the 21st century.

Chronic Disease↗
PubMed2006

Contribution to the Detection and Identification of Oxidation Metabolites of Nonylphenol in Sphingomonas sp. strain TTNP3.

Sphingomonas sp. strain TTNP3 has been previously described as a bacterium that is capable of degrading the technical mixture of nonylphenol (NP) isomers and also the 4(3',5'-dimethyl-3'-heptyl)-phenol single isomer of NP. Until recently, 3,5-dimethyl-3-heptanol was the only reported metabolite of 4(3',5'-dimethyl-3'-heptyl)-phenol. A short time ago, the detection of an intracellular metabolite resulting from the oxidation of 4(3',5'-dimethyl-3'-heptyl)-phenol which was identified as 2(3,5-dimethyl-3-heptyl)-benzenediol has been reported. A decisive element for this identification was the occurrence of some slight differences with the two most probable metabolites i.e. 4(3',5'-dimethyl-3'-heptyl)-resorcinol and 4(3',5'-dimethyl-3'-heptyl)-catechol. These facts led us to hypothesise some NIH shift mechanisms explaining the formation of 2(3',5'-dimethyl-3'-heptyl)-benzenediol. In the present work, we describe the steps that led to the detection of these metabolites in the intracellular fraction of Sphingomonas sp. strain TTNP3. The formation of analogous intracellular metabolites resulting from the degradation of the technical mixture of NP is reported. To further elucidate these degradation products, studies were carried out with cells grown with 4(3',5'-dimethyl-3'-heptyl)-phenol as sole carbon source. The description of the syntheses of reference compounds, i.e. 4(3',5'-dimethyl-3'-heptyl)-resorcinol and 4(3',5'-dimethyl-3'-heptyl)-catechol and their comparative analyses with the intermediates of the degradation of 4(3',5'-dimethyl-3'-heptyl)-phenol are presented.

Chromatography, High Pressure Liquid↗
PubMed2006

On the unusual fluorescence properties of xanthone in water.

Photo-excited xanthone is known to undergo ultrafast intersystem crossing (ISC) in the 1 ps time domain. Correspondingly, its fluorescence quantum yield in most solvents is very small ( approximately 10(-4)). Surprisingly, the quantum yield in water is 100 times larger, while ISC is still rapid ( approximately 1 ps), as seen by ultrafast pump probe absorption spectroscopy. Temperature dependent steady state and time resolved fluorescence experiments point to a delayed fluorescence mechanism, where the triplet (3)npi* state primarily accessed by ISC is nearly isoenergetic with the photo-excited (1)pipi* state. The delayed fluorescence of xanthone in water decays with a time constant of 700 ps, apparently by internal conversion between the (3)npi* state and the lowest lying triplet state (3)pipi*.

Luminescence↗
PubMed2006

Early prediction of poor outcome in extremely low birth weight infants by classification tree analysis.

OBJECTIVE: To predict death or neurodevelopmental impairment (NDI) in extremely low birth weight infants by classification trees with recursive partitioning and automatic selection of optimal cut points of variables. STUDY DESIGN: Data from the Trial of Indomethacin Prophylaxis in Preterms were randomly divided into development (n=784) and validation sets (n=262). Three models were developed for the combined outcome of death (8 days to 18 months) or NDI (cerebral palsy, cognitive delay, deafness, or blindness at 18 months corrected age): antenatal: antenatal data; early neonatal: antenatal+first 3 days data; and first week: antenatal, first 3 days, and 4th to 8th days data. Decision trees were tested on the validation set. RESULTS: Variables associated with death/NDI in each model were: Antenatal: Gestation 01 mL/kg/d. First week: Birth weight 3 mL/kg/d. Birth weight>787 g: cranial echodense intraparenchymal lesion and transfusion>1 mL/kg/d. Correct classification rates were 61% to 62% for all models. CONCLUSIONS: The ability to predict long-term morbidity/death in extremely low birth weight infants does not improve significantly over the first week of life. Effects of different variables depend on age.

Decision Trees↗
PubMed2006

The influence of downstream arterial perfusion parameters on doppler pulsatility index and resistance index in an in-vitro perfusion model.

BACKGROUND: To investigate in vitro how downstream perfusion parameters influence pulsatility index (PI), resistance index (RI) and their constituting Doppler velocities. MATERIALS AND METHODS: We analyzed the influence of resistance, compliance, reflection coefficient and input impedance on PI and RI in an in-vitro model of arterial flow. RESULTS: The nominators of PI and RI were determined by resistance. The numerators were determined by compliance and by the reflection coefficient. There were close relationships of PI and RI with resistance under the condition of constant compliance, but not when compliance was variable. CONCLUSION: PI and RI consist of velocity terms which are independently influenced by different parameters of impedance: compliance, reflection coefficient and resistance. These findings explain the contradictory results reported for the relationship between the indices and peripheral resistance in studies where compliance and reflection effects were not considered.

Animals↗
PubMed2006

Oxidative metabolic profiling of xenobiotics by human P450s expressed in tobacco cell suspension cultures.

Elucidation of metabolic pathways of xenobiotics (pesticides, pharmaceuticals and industrial pollutants) in human, animals and plants and chemical identification of corresponding metabolites are required for comprehensive (eco-) toxicological evaluation of the compounds prior to their usage. The most important metabolic products are oxidized metabolites, and most of these are formed by catalytic activity of P450s (cytochrome P450 mono-oxygenases). In human, 11 P450 isoenzymes exhibiting broad and overlapping substrate specificities are responsible for approx. 90% of drug metabolism. As support for inevitable metabolism studies with intact organisms under relevant conditions, tobacco cell cultures were transformed separately with cDNA sequences of human P450 isoenzymes CYP1A1, CYP1A2 and CYP3A4. The resulting P450-transgenic cell suspensions were used for metabolism studies with pesticides, industrial pollutants, a secondary plant metabolite and human sex hormones. A summary of basic results is provided; these are discussed regarding application of the method for screening of the oxidative metabolism of xenobiotics and the large-scale production of metabolites.

Animals↗
PubMed2006

Dysplastic naevi with moderate to severe histological dysplasia: a risk factor for melanoma.

BACKGROUND: The risk of malignant melanoma associated with histologically dysplastic naevi (HDN) has not been defined. While clinically atypical naevi appear to confer an independent risk of melanoma, no study has evaluated the extent to which HDN are predictive of melanoma. OBJECTIVES: To estimate the risk of melanoma associated with HDN. Secondarily, the risk associated with number of naevi and large naevi is estimated. METHODS: We enrolled 80 patients with newly diagnosed melanoma along with 80 spousal controls. After obtaining information on melanoma risk factors and performing a complete cutaneous examination, the most clinically atypical naevus was biopsied in both cases and controls. Histological dysplasia was then assessed independently by 13 dermatopathologists (0, no dysplasia; 1, mild dysplasia; 2, moderate dysplasia; 3, severe dysplasia). The dermatopathologists were blinded as to whether the naevi were from melanoma subjects or controls. Multivariate analyses were performed to determine if there was an independent association between the degree of histological dysplasia in naevi and a personal history of melanoma. RESULTS: In persons with naevi receiving an average score of > 1 (i.e. naevi considered to have greater than mild histological dysplasia), there was an increased risk of melanoma [odds ratio (OR) 2.60, 95% confidence interval (CI) 0.99-6.86] which persisted after adjustment for confounders (OR 3.99, 95% CI 1.02-15.71). Very few dermatopathologists reliably graded naevi of subjects with melanoma as being more dysplastic than naevi of control subjects. Among the entire group, the interobserver reliability associated with grading histological dysplasia in naevi was poor (weighted kappa 0.28). CONCLUSIONS: HDN do appear to confer an independent risk of melanoma. However, this result may add more to our biological understanding of melanoma risk than to clinical assessment of risk, because HDN assessed by a single pathologist generally cannot be used to assess risk of melanoma. Future studies should be directed at establishing reproducible, predictive criteria for grading naevi.

Adult↗
PubMed2006

Frequency of dystrophic muscle abnormalities in chronic progressive external ophthalmoplegia: analysis of 86 patients.

BACKGROUND: There are few reports describing the coexistence of dystrophic features with those typical of mitochondrial myopathies in muscle biopsy. A recent study suggested that dystrophic features are frequent in patients with chronic progressive external ophthalmoplegia (CPEO) with a high mutation load, but the actual frequency of these abnormalities in CPEO remains undetermined. OBJECTIVE: To review the occurrence of dystrophic abnormalities in a large series of patients with CPEO to assess the frequency of such abnormalities and to verify whether they are correlated with specific mitochondrial DNA (mtDNA) mutations. METHODS: Retrospective survey of case series (86 patients with CPEO). RESULTS: Only three cases with dystrophic abnormalities were found: two with a large scale mtDNA deletion and one with the A3251G mutation. All three patients showed predominantly proximal muscular weakness resembling limb girdle muscular dystrophy. CONCLUSIONS: Dystrophic abnormalities are rare in CPEO and are not correlated with a specific molecular defect.

Adult↗
PubMed2006

Peri-prosthetic bone density after implantation of a custom-made femoral component. A five-year follow-up.

Peri-prosthetic bone loss caused by stress shielding may be associated with aseptic loosening of femoral components. In order to increase primary stability and to reduce stress shielding, a three-dimensional, cementless individual femoral (Evolution K) component was manufactured using pre-operative CT scans. Using dual energy x-ray absorptiometry, peri-prosthetic bone density was measured in 43 patients, three months, six months, 3.6 and 4.6 years after surgery. At final follow-up there was a significant reduction in mean bone density in the proximal Gruen zones of -30.3% (zone 7) and -22.8% (zone 1). The density in the other zones declined by a mean of between -4% and -16%. We conclude that the manufacture of a three-dimensional, custom-made femoral component could not prevent a reduction in peri-prosthetic bone density.

Absorptiometry, Photon↗
PubMed2005

[Bronchial artery embolisation using platinum coils in 52 patients with severe pulmonary hemorrhage].

BACKGROUND: Severe pulmonary hemorrhage ist life-threatening. One of the treatment options in case of severe pulmonary hemorrhage is bronchial artery embolisation (BAE) with different embolisation materials. PATIENTS AND METHODS: Efficacy of BAE using platinum coils was investigated retrospectively in a total of 52 patients. 22 suffered from benign lung diseases (angiodysplasia, inflammation, bronchiectasia) and 30 patients had lung cancer (lung metastases in two cases). RESULTS: Primary hemostasis was achieved in over 90 % of the patients (47 of 52). Recurrent BAE was necessary in 23 % of patient with benign etiologies and in 50 % of the tumor patients. Comparing the results of the lung cancer patients with a control group from a teaching hospital without BAE we found survival-advantages for those patients treated with BAE. CONCLUSION: Our results underline the usefulness of BAE in severe pulmonary hemorrhage.

Adult↗
PubMed2005

[Pulmonary bleeding after lung transplantation].

BACKGROUND: Bronchial arteries are not anastomosed during lung transplantation. We analyzed the occurrence of pulmonary hemorrhage after transplantation. PATIENTS AND METHODS: 235 patients were included. RESULTS: We observed pulmonary bleeding in 4/235 patients (1.7 %). All four cases were due to transplant-specific disorders (arrosion of pulmonary artery in three cases, coagulopathy in one patient). CONCLUSIONS: The analysis shows, that usual pulmonary hemorrhage does not occur in lung transplant recipients. This underlines the role of bronchial arteries in pulmonary hemorrhage of non-LTX-patients.

Adolescent↗
PubMed2005

Excited-state dynamics of bacteriorhodopsin probed by broadband femtosecond fluorescence spectroscopy.

The impact of varying excitation densities (approximately 0.3 to approximately 40 photons per molecule) on the ultrafast fluorescence dynamics of bacteriorhodopsin has been studied in a wide spectral range (630-900 nm). For low excitation densities, the fluorescence dynamics can be approximated biexponentially with time constants of <0.15 and approximately 0.45 ps. The spectrum associated with the fastest time constant peaks at 650 nm, while the 0.45 ps component is most prominent at 750 nm. Superimposed on these kinetics is a shift of the fluorescence maximum with time (dynamic Stokes shift). Higher excitation densities alter the time constants and their amplitudes. These changes are assigned to multi-photon absorptions.

Bacteriorhodopsins↗
PubMed2005

Fuzzy pattern classification of hemodynamic data can be used to determine noninvasive intracranial pressure.

OBJECTIVE: The authors previously introduced a method in which intracranial pressure (ICP) was estimated using parameters (TCD characteristics) derived from cerebral blood flow velocity (FV) and arterial blood pressure (ABP). Some results suggested that this model might be influenced by the patient's state of cerebral autoregulation and other clinical parameters. Hence, it was the aim of the present study to improve the method by modifying the previously used global procedure in certain subgroups of patients. METHODS: In 103 traumatic brain injured patients (3-76 years, mean: 31 +/- 16 years) signal data of FV, ABP and ICP were used to generate samples of TCD characteristics together with time corresponding ICP. Fuzzy Pattern Classification was used to identify cluster subsets (classes) of the sample space. On each class a local estimator of ICP was defined. This approach provides a non-invasive assessment of ICP (nICP) as follows: Using FV and ABP the TCD characteristics were computed and related to the matching classes. nICP was calculated as a weighted sum of local ICP estimations. RESULTS: ICP A and B waves and long-term trends could be visibly assessed. The median absolute difference between ICP and nICP was 5.7 mmHg. CONCLUSIONS: The class structure of the model facilitates nICP assessment in heterogeneous patient groups and supports a stepwise extension of the target patient group without affecting the former validity.

Adolescent↗