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Biomedical subjects

M Wolf

Publications and source records attributed to M Wolf.

At least 109 records · Page 6Linked to original sources
PubMed2000

[Plea for interdisciplinary dimension in medicine. The example of consent].

A philosophical and legal analysis of consent in the patient-doctor relationship leads to operational limitations. Getting over these limits requires a transdiciplinary approach aimed at understanding the living world and modeling its evolution. This approach rests on recognition of different philosophical, legal, sociological, economical, and historical reality levels, permitting a new non-exclusive role of consent in medicine, i.e. the respect of human dignity.

Humans↗
PubMed2000

Can near infrared spectroscopy of the liver monitor tissue oxygenation?

Measurement of the hepatic oxygenation index by near infrared spectroscopy is a suitable method to estimate the oxygenation and can be a non-invasive means to continuously monitor tissue perfusion and to detect early haemodynamic disturbances in critically ill children.

Child, Preschool↗
PubMed2000

Lipoprotein lipase gene polymorphism, cholesterol subfractions and myocardial infarction in large samples of the general population.

OBJECTIVE: Genetic variants of the lipoprotein lipase gene have been associated with dyslipidemia and coronary artery disease. However, data have been inconsistent and are mainly based on selected predominantly male patient groups. METHODS: We evaluated the influence of the HindIII restriction fragment length polymorphism on lipid levels in the general population (1361 participants of a large population-based survey from Augsburg, Germany; 50% women) as well as the association of this polymorphism with the risk of myocardial infarction (MI; genotype frequencies in 1159 patients with documented MI under 60 years of age). RESULTS: In the population-based survey, a highly significant association between the frequent H2H2 genotype and unfavorable cholesterol subfraction levels was observed in men and in postmenopausal women whereas no significant association was observed in premenopausal women (uni- and multivariate analysis). Such unfavorable lipid levels in homozygotes for the H2 allele may be expected to be associated with a 19-25% increased risk to suffer from myocardial infarction (MI). Nevertheless, genotype and allele frequencies in the general population were not different from those in patients with previous MI (H2H2 genotype frequency 51.3% vs. 53.2%, respectively; P=0.63). CONCLUSION: This large study shows that the H2H2 genotype of the lipoprotein lipase gene polymorphism is associated with unfavorable lipid levels. Estrogen status may modulate this association in women. The effects of the genotype on lipid levels were apparently not strong enough to reveal a significant association with MI.

Adult↗
PubMed2000

Application of a purge and trap TDS-GC/MS procedure for the determination of emissions from flame retarded polymers.

Emissions of volatile organic compounds (VOCs) from different thermoplastic polymers used in electrotechnical applications were investigated using a purge and trap procedure that involved adsorption on Tenax GR. Results were compared to those for an operating TV set monitored in a test chamber. The analyses were in both cases carried out using thermodesorption gas chromatography with mass spectrometric detection (TDS-GC/MS). Substances identified were monomers, volatile additives, or related compounds. Special attention was given to the detection of halogenated compounds. Their origin was studied using reference samples and synthetic standards.

Air Pollutants↗
PubMed2000

Novel findings in gene expression detected in human osteosarcoma by cDNA microarray.

cDNA microarray analysis was used to screen for gene expression alterations in human osteosarcoma cell lines. The analysis using three cell lines revealed changes in the expression of several genes in comparison with normal human osteoblasts. Among the 5,184 sequences that were analyzed, 35 showed aberrant expression in all the cell lines. Eight of these showed overexpression and 27 underexpression compared to their expression levels in osteoblasts. The most highly up-regulated genes included heat shock protein 90beta and polyadenylate-binding protein-like 1. Commonly down-regulated genes included fibronectin 1 and thrombospondin 1. RT-PCR was used to verify these changes in the cell lines and in three primary osteosarcoma samples. This study shows that (1) gene expression pattern in osteosarcoma cell lines differs considerably from normal osteoblasts, (2) osteosarcoma cell lines can be used as a model system to detect novel gene expression alterations present in primary tumors, (3) the overexpression of heat shock protein 90beta and polyadenylate-binding protein-like 1, and (4) the down-regulation of fibronectin 1 and thrombospondin 1 may play a role in the development and/or progression of osteosarcoma. This study indicates that microarray-based expression surveys may be used to establish the molecular fingerprint of osteosarcoma, however, larger cDNA chips and more tumor specimens are required to define the clinically relevant gene expression patterns.

DNA, Complementary↗
PubMed2000

Neoadjuvant chemoradiotherapy of stage III non-small-cell lung cancer.

Twenty to 30% of patients with non-small-cell lung cancer (NSCLC) in stage III are not resectable primarily with 5-year survival less than 10%. Since the majority of patients die from metastases, efforts have been made in the past to improve prognosis by application of neoadjuvant chemoradiotherapy regimens followed by subsequent resection. In a phase II study performed between 1993 and 1998, 93 patients in stage III (IIIA, 16%; IIIB, 84%) received an induction chemotherapy consisting of two cycles cisplatin (100 mg/m2) and vindesine (3 mg/m2) with subsequent sequential radiotherapy of 36 Gy. Sixty-five patients demonstrated partial or complete remission. Sixty underwent surgery; in 49 of them complete resection was possible. Five-year survival in the whole group was 24%, and that in the surgical cohort 39%. Six patients had no residual tumor. Postoperative N0 status was associated with a 5-year survival of 75%, and stage N1-3 with 13%. Thirty-day mortality was 7% postoperatively. Neoadjuvant chemoradiotherapy can significantly improve long-term survival in stage III NSCLC with an acceptable therapy-induced mortality.

Adult↗
PubMed2000

Thrombotic risk factors in pulmonary hypertension.

Thrombotic lesions are consistently observed in chronic thromboembolic pulmonary hypertension (CTEPH) and frequently found in primary pulmonary hypertension (PPH). It remains unknown, however, whether thrombosis is related to defects of the antithrombotic pathway or to previous vascular injury. This study therefore analysed the frequency of both hereditary and acquired thrombotic risk factors in CTEPH and PPH. One hundred and forty-seven consecutive patients with CTEPH investigated in the author's institution were compared to 99 consecutive patients with PPH. In 116 CTEPH patients and 83 PPH patients, phospholipid-dependent antibodies (antiphospholipid antibodies and lupus anticoagulant) were analysed by both immunological and clotting assays. In patients enrolled since 1994 (46 CTEPH and 64 PPH), hereditary thrombotic risk factors were also determined. Antithrombin, protein C and protein S activities were measured by functional assays. Mutations of factor V and factor II were identified by polymerase chain reaction. The prevalence of hereditary thrombotic risk factors was not increased in patients with either PPH or CTEPH. In contrast, a high frequency of phospholipid-dependent antibodies was observed in PPH (10%) and more notably in CTEPH (20%). Moreover, in PPH, antibodies were present only in low titre whereas in CTEPH, half of the patients with antiphospholipid antibodies had high titres. In addition, in CTEPH all but one of the patients with lupus anticoagulant also had antiphospholipid antibodies. The most striking finding of this study was the high prevalence of phospholipid-dependent antibodies but their clinical relevance appears to be different in primary pulmonary hypertension and chronic thromboembolic pulmonary hypertension. In primary pulmonary hypertension, these antibodies in low titre probably reflect endothelial dysfunction. In contrast, in chronic thromboembolic pulmonary hypertension the presence of antibodies in high titre associated with lupus anticoagulant, underlines the role of thrombosis in the pathogenesis of this condition.

Antibodies, Antiphospholipid↗
PubMed2000

Docetaxel effectively mobilizes peripheral blood CD34+ cells.

We prospectively evaluated docetaxel (100 mg/m2) with G-CSF (10 microg/kg S.C., daily) for mobilization efficiency in 26 patients with breast cancer. The minimum target yield was >4.5 x 10(6) CD34+ cells/kg (optimum = 9 x 10(6)/kg), sufficient to support the subsequent three cycles of high-dose therapy (HDT). The peak days for peripheral blood (PB) CD34+ cells were day 8 and day 9. Seven collections began on day 7, 16 on day 8 and three on day 9. The median peripheral blood progenitor cell (PBPC) CD34+ cell content ranged from 1.2 to 5.9 x 10(6)/kg per day during days 7 to 11 with a median CD34+ content of the total 72 PBPC collections of 3.4 x 10(6)/kg (0.07-15.6). Fifteen patients obtained a PBPC collection exceeding 5 x 10(6)/kg on a single day of collection. Following a median 3 days collection for each patient (range 2-4), the median total CD34+ for all individual sets of collections was 9.7 x 10(6)/kg (range 1.0-28.4). We were able to achieve the minimum CD34+ cell target yield in 22 of 26 patients with one cycle of mobilisation chemotherapy and in two of these patients a second collection yielded sufficient cells. Twenty-two patients have subsequently received repetitive HDT and PBPC transplantation with 57 cycles of HDT having been delivered. For all 57 cycles, the median time to absolute neutrophil count (ANC) >0.5 x 10(9)/l and 1.0 x 10(9)/l was 10 days (range 8-22) and 11 days (range 8-23), respectively. The median time to platelets greater than 20 x 10(9)/l, 50 x 10(9)/l and 100 x 10(9)/l was 13 days (range 11-23), 17 days (range 12-53) and 23 days (range 18-70), respectively. We conclude that docetaxel with G-CSF effectively mobilises PBPCs with apheresis needing to be commenced approximately 8 days after docetaxel administration.

Adult↗
PubMed2000

Repetitive high-dose therapy with cyclophosphamide, thiotepa and docetaxel with peripheral blood progenitor cell and filgrastim support for metastatic and locally advanced breast cancer: results of a phase I study.

This phase I study was designed to determine the optimal dosages of a novel repetitive high-dose therapy regimen for patients with metastatic breast cancer (MBC). The planned treatment was three cycles of high-dose cyclophosphamide, thiotepa and docetaxel delivered every 35 days with progressive dose-escalation in successive cohorts. Each cycle was supported by peripheral blood progenitor cells (PBPC) and filgrastim. Eighteen patients were entered into this trial. Of the planned 54 treatment cycles, 44 were delivered and 11 patients completed all three cycles. The dose-limiting toxicities were interstitial pneumonitis and mucositis with moderately severe diarrhea (n = 3) and rash (n = 3). There were no treatment-related deaths. Of the 17 patients with evaluable disease, 16 patients responded with six patients achieving a complete remission and an additional four patients achieving no detectable disease (negative restaging including PET scan) but a persistently abnormal bone scan. At a median follow-up of 12 months, median progression-free survival was 11 months with the median overall survival not reached. The recommended doses for phase II/III studies are cyclophosphamide (4 g/m2), thiotepa (300 mg/m2) and docetaxel (100 mg/m2).

Adult↗
PubMed2000

Structure and dynamics of excited electronic states at the adsorbate/metal interface: C6F6/Cu(111).

Excited state electron transfer at the adsorbate/metal interface represents a key step in molecular electronic devices. The dynamics of such processes are governed by ultrafast energy relaxation which can be probed directly by time-resolved two-photon photoemission (2PPE). Using 2PPE spectroscopy we investigate the energetics and lifetimes of the unoccupied electronic states of C6F6 adsorbed on Cu(111) as a model system for electron transfer at organic/metal interfaces. With increasing C6F6 layer thickness we find a pronounced decrease in the energetic position of the lowest unoccupied state, which is accompanied by a strong increase in its lifetime as well as a decrease in the effective electron mass. The frequently employed dielectric continuum model which describes delocalized (quantum well) states within adsorbate layers does not give a consistent explanation of these findings. By adsorption of Xe overlayers onto C6F6/Cu(111) we can show that, even for one monolayer of C6F6, the excited state must be localized predominantly inside the C6F6 layer and thus originates from a molecular state (presumably an antibonding sigma* orbital). With increasing coverage this state becomes more delocalized within the adsorbate layer, which reduces the coupling to the metal substrate and thus enhances the excited state lifetime.

Journal Article↗
PubMed2000

The value of the occipitomental (Waters') view in diagnosis of sinusitis: a comparative study with computed tomography.

AIM: Sinus X-rays are still frequently used in the evaluation of paranasal sinusitis. Many radiology departments nowadays provide the referring doctors with a single Waters' projection. Our purpose was to evaluate the diagnostic accuracy of a single Waters' view vs high resolution computed tomography (CT) in the diagnosis of paranasal sinusitis. SUBJECTS AND METHODS: A total of 134 patients with suspected paranasal sinusitis underwent a Waters' view X-ray and high resolution CT on the same day. The radiographs were evaluated independently by nine experienced radiologists, who observed each sinus separately. Sensitivity, specificity, accuracy, positive and negative predictive values were calculated for each sinus and for each observer, using the CT findings as a 'gold standard'. RESULTS: The weighted mean sensitivity for diagnosis of any abnormality in the maxillary sinus was 67.7%, specificity 87.6%, accuracy 78.6%, positive predictive value 82.5% and negative predictive value 76.9%. For this sinus the variation between observers was small, however, the sensitivity for diagnosis of any disease in the frontal and ethmoid sinuses varied widely between observers (range 1.9-54.0% and 0-58.9%, respectively). The sensitivity for the sphenoid sinus was very low (range 0-3.8%), even in radiographs which seemed to demonstrate it well. CONCLUSION: The Waters' view has its limits in the diagnosis of sinusitis of the maxillary sinuses and its contribution for diagnosing lesions in the remaining sinuses is very poor. Whenever access to CT is available, a low dose high-resolution CT study of the paranasal sinuses is highly recommended.Konen, E. (2000). Clinical Radiology55, 856-860.

Adolescent↗
PubMed2000

[Calculating dental fees--a 1988-1999 trend analysis].

German GOZ (Gebührenordnung für Zahnärzte, catalogue of dental services) allows multipliers within a range from 1.0 to 3.5 for each fee, and it also prescribes medical arguments if dentists want to justify multipliers beyond 2.3. The authors analyze formal and material developments in these medical arguments of more than 3500 invoices from 1988 to 1999. Since 1988--amendment of GOZ--a development can be seen away from more general and patient-focussed towards arguments dealing with new dental materials and new forms of dental treatment. The authors analyse the way dentists (private ones and dentists of health insurance system), orthodontists, maxillo-facial- and oral surgeons charge their fees.

Fee Schedules↗
PubMed2000

Tissue oxygen saturation measured by near infrared spectrophotometry correlates with arterial oxygen saturation during induced oxygenation changes in neonates.

The aim of this study was to compare quantitatively the changes in tissue oxygen saturation (TOS), determined by two algorithms (TOSc and TOSa) based on near-infrared spectrophotometry, to the changes in arterial oxygen saturation (SaO2) measured by pulse oximetry. TOSc is an algorithm derived by the manufacturer (Critikon) based on a modified Beer-Lambert law; TOSa, our own algorithm, uses the diffusion approximation of light transport for the semi-infinite boundary condition. Slow changes of more than 3% in SaO2 were carried out in 20 mechanically ventilated neonates by altering the inspired oxygen fraction. For each change the regression lines of TOSc versus SaO2, TOSa versus SaO2 and TOSc versus TOSa were calculatcd. For each infant the mcan slope, intercept and r2 of these lines were determined. In 18 preterm infants we obtained median 9.5 (range one to 13) measurements corresponding to a total of 166 measurements. The mean SaO2 was 91.6 (SD 2.3)%, TOSc was 64.7 (SD 7.2)% and TOSa was 71.4 (SD 11.0)%. Changes in TOSc and TOSa were strongly correlated to changes in SaO2 (r2 = 0.86 and r2 = 0.87). TOSc considerably but systematically underestimated the size of the change: delta TOSc = 0.49 delta SaO2. TOSa quantified changes reasonably correctly: delta TOSa = 0.90 delta SaO2. Changes in TOSc and TOSa were highly correlated (r2 = 0.98). These results are promising, but the large inter-individual variation requires further work.

Algorithms↗
PubMed2000

Postsurgical prevertebral abscess of the cervical spine.

OBJECTIVES: Prevertebral abscess formation is an uncommon occurrence following cervical spine fusion surgery. Abscesses may present early or in a delayed fashion and require surgical drainage and long-term antibiotic treatment. The issues of osteomyelitis and the need for plate removal remain unresolved. STUDY DESIGN: A case series of six tetraplegic patients admitted for rehabilitation to the Chaim Sheba Medical Center (Tel Hashomer, Israel) is presented. METHODS: Five patients were trauma patients; one patient underwent repeated procedures and irradiation for tumor of the cervical spine. All patients developed prevertebral abscesses after a mean period of 30 days from their fusion surgery. Computed tomography scan was used in all patients to establish the diagnosis and define the extent of the infective process. All patients underwent one or more drainage procedures. The plate was removed in two patients at 1 and 4 months. RESULTS: Infection completely resolved in four patient and was refractory in one patient with malignant tumor, and a chronic small fistula remained in one case. Staphylococcus aureus was the main infective organism, but mixed infections were the rule. Even for a protracted course of infection, no significant osteomyelitis was encountered. CONCLUSIONS: Abscess formation after instrumentation of the neck may be more common than formerly recognized. Despite the prolonged course of disease and treatment, osteomyelitis is not a major concern. There is no automatic indication for plate removal to control infection, although plating may be safely removed after 10 to 12 weeks if the neck is explored and the cervical spine is stable. A high index of suspicion is warranted, and early recognition and diagnosis, prompt surgical drainage under general anesthesia, and long-term antibiotic treatment are key for eradication of the infective process. Prophylactic antibiotics may be of value. Meticulous antisepsis and surgical technique should be maintained to reduce the incidence of these severe complications.

Abscess↗
PubMed2000

Near-infrared study of fluctuations in cerebral hemodynamics during rest and motor stimulation: temporal analysis and spatial mapping.

We have noninvasively studied the motor cortex hemodynamics in human subjects under rest and motor stimulation conditions using a multichannel near-infrared tissue spectrometer. Our instrument measures optical maps of the cerebral cortex at two wavelengths (758 and 830 nm), with an acquisition time of 160 ms per map. We obtained optical maps of oxy- and deoxy-hemoglobin concentration changes in terms of amplitudes of folding average, power spectrum and coherence at the stimulation repetition frequency, and the phase synchronization index. Under periodic motor stimulation conditions, we observed coherence and frequency or phase synchronization of the local hemodynamic changes with stimulation. Our main findings are the following: (1) The amplitude of the hemodynamic response to the motor stimulation is comparable to the amplitude of the fluctuations at rest. (2) The spatial patterns of the oxy- and deoxy-hemoglobin responses to the stimulation are different. (3) The hemodynamic response to stimulation shows a spatial localization and a level of phase synchronization with the motor stimulation that depends on the stimulation period.

Adult↗
PubMed2000

Neurological dysfunction, psychic conflict, and psychotherapy.

Clinical experience of psychotherapists is getting more and more circumscribed by the boundaries of theoretical references. The Freudian "psychic treatment" for neurosis got its impetus from the friendship between Sigmund Freud and Ludwig Binswanger, the phenomenological psychiatrist. This relationship laid the foundation for the references of psychoanalytic psychotherapy in Europe. Then, the Freudian conception of actual neurosis led to a psychosomatic approach. Later, the study of narcissistic neurosis opened up to borderline patients. Today, scientific and medical progress greatly influence psychopathological research and the way we look at our patients and their requests. These changes come from the patients' sayings and their expectancy of well-being. At the same time psychotherapists have to take a new look at their theoretical references. On the one hand, a dynamic concept for psychotherapy is necessary for integrating the phenomenologic approach into psychoanalysis, and providing the understanding of situations emerging in neurological dysfunction. On the other hand, psychotherapists pay more attention to the different actors contributing to a pathology (Who is suffering? What about the life-partner or the relatives?). These changes lead to a new look into the processes of identification as well as the notion of identity. This article discusses these influences on psychotherapy and clinical research showing how clinical situations get ahead of theoretical references.

Brain↗