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Biomedical subjects

M Franz

Publications and source records attributed to M Franz.

At least 19 recordsLinked to original sources
PubMed2006

Superfluid density of strongly underdoped cuprate superconductors from a four-dimensional XY model.

A new phenomenology is proposed for the superfluid density rhos of strongly underdoped cuprate superconductors based on recent data for ultraclean single crystals of YBa2Cu3O7-x. We show that the puzzling departure from Uemura scaling and the decline of the slope as the Tc=0 quantum critical point is approached can be understood in terms of the renormalization of quasiparticle effective charge by quantum fluctuations of the superconducting phase. We then employ a (3+1)-dimensional XY model to calculate, within particular approximations, the renormalization of rhos and its slope, explain the new phenomenology, and predict its eventual demise close to the quantum critical point.

Journal Article↗
PubMed2006

[The process of deinstitutionalization in German State Mental Hospitals. Critical overview of empirical research studies].

The process of discharging previously long-term hospitalized patients from German state mental hospitals, and of transferring these patients to other forms of supported housing has meanwhile come to its end. Therefore, this paper presents an overview of the scientific evaluation of this process. By using clearly defined research methodological criteria, eight empirical studies from several German federal states are assessed focusing on the meaningfulness of their results. Because of the heterogeneity of the aims regarding contents of this transformation process, of the research methodological approaches, and of the characteristics of the assessed patient groups, only few general results could be identified. Chronically mentally ill patients (mostly suffering from schizophrenic disorders) who had been successfully discharged to the community were younger, and showed shorter periods of illness and hospitalization than control patients. After discharge they might have experienced positive changes of their objective and subjective quality of life and of their perceived needs of care. Referred to several other outcome domains, no homogeneous tendencies concerning clinically relevant improvement or deterioration were found. In particular, changes related to psychopathological symptoms and social competencies were generally small. However, mortality and re-hospitalization rates of de-hospitalized patients were considerably high, and ranged between 3-24 %, and 4-46 %, respectively. The assessed studies could not identify replicated predictors of successful de-hospitalization. Female sex and long-term last hospitalization seemed to be important for stable placement in forms of supported housing requiring a higher level of autonomy. From the generally unclear procedural quality of the German deinstitutionalization process, the authors deduce implications for the scientific evaluation of future projects of restructuring mental health care services. Besides the clear definition of empirically assessable aims which should be based on theoretical considerations, it is of utmost priority to guarantee high performance quality of research methodological standards.

Adult↗
PubMed2005

[Perceptions of quality of life in schizophrenic patients].

BACKGROUND: Subjective quality of life in schizophrenic persons is a commonly applied indicator in outcomes research. However, it remains unclear whether the content of the construct is adequately represented from the patients' point of view, and whether changing representations in the course of illness should be accounted for in terms of re-prioritization of the concept. PURPOSE: Identification of specific perceptions of quality of life (QoL) of schizophrenic persons and analysis of changes of those perceptions with increasing chronicity. METHODS: The present study is a reanalysis of responses to a short, structured, open-ended interview taken from different studies in social psychiatry research. 403 schizophrenic persons from different care settings (psychiatric hospitals, community based institutions) as well as 178 mentally healthy persons were interviewed with regard to positive and negative aspects of their QoL. A qualitative content-analysis resulted in a comprehensive hierarchy of categories. The proportion of persons who mentioned a respective QoL-aspect was compared. Relationship between chronicity and perceptions of QoL were analysed by means of chi (2)(trend)-tests. RESULTS: Schizophrenic persons mentioned about one fewer QoL domain compared to the mentally healthy (8.3 (sd = 2.8) vs. 9.6 (sd = 2.0), P < 0.001). They had fewer assertions on work aspects as well as in social domains (family, social relationships, partnership). The proportion of statements in social domains was negatively associated with the degree of chronicity. Among other things the schizophrenic persons showed a higher proportion of statements regarding "oral needs" (food, drinking-related statements, smoking) and (problems with) daily activities; both domains were associated with the degree of chronicity. DISCUSSION: Differences between schizophrenic and mentally healthy persons in their perceptions of QoL were more pronounced with increasing chronicity. It remains unclear at which point in the course of illness this is best understood in terms of re-prioritization or even re-conceptualization of the entire concept.

Adult↗
PubMed2004

Survival of the d-wave superconducting state near the edge of antiferromagnetism in the cuprate phase diagram.

In the cuprate superconductor YBa2Cu3O6+x, hole doping in the CuO2 layers is controlled by both oxygen content and the degree of oxygen ordering. At the composition YBa2Cu3O6.35, the ordering can occur at room temperature, thereby tuning the hole doping so that the superconducting critical temperature gradually rises from 0 to 20 K. Here we exploit this to study the c-axis penetration depth as a function of temperature and doping. The temperature dependence shows the d-wave superconductor surviving to very low doping, with no sign of another ordered phase interfering with the nodal quasiparticles. The only apparent doping dependence is a smooth decline of superfluid density as T(c) decreases.

Journal Article↗
PubMed2004

Demonstration of antibodies to the chitin-binding mistletoe lectin (cbML) in tumor patients before and during therapy with an aqueous mistletoe extract.

Mistletoe extracts exert immunomodulatory properties in vivo and in vitro, and these effects have been related mainly to mistletoe lectin 1 (ML-1). Recently, a new chitin-binding mistletoe lectin (cbML) has been isolated and structurally characterized in these extracts. Aim of the present study was, therefore, to evaluate whether this cbML also affects immunocompetent cells and can for instance activate B-cells to produce anti-cbML-specific antibodies. Sera from patients with different tumors who were treated with the mistletoe extract ABNOBAviscum Mali (AM) 4 for at least 18 weeks were analysed before therapy and after 3, 6, 9, 12, 18, and 24 weeks. Sera were tested by ELISA against ML-1, -3, and cbML, isolated from a single mistletoe plant collected from an apple tree (Malus domestica). Eight of the 26 patients (31%) had IgG anti-cbML antibodies already before therapy, while only four had anti-ML-1 and -3 antibodies. Of the 18 anti-cbML negative patients before therapy 54% developed these antibodies during therapy, and there was a significant increase in anti-cbML antibody titers. In contrast, anti-ML-1 or -3-antibodies developed in almost 100% of the 25 patients being negative before therapy. These data indicate that cbML can induce immunological responses in patients treated with mistletoe extracts, although it seems to have lower antigenicity. Interestingly, anti-cbML antibodies can be observed in a low incidence also in individuals, not having yet received mistletoe therapy.

Adjuvants, Immunologic↗
PubMed2004

Depression and anxiety in different thyroid function states.

Previous studies on hypothyroid subjects have indicated serious psychiatric symptoms affecting the patients' quality of life. The present prospective cross-sectional study's aim was to examine these symptoms in thyroid patients with different functional states. A total of 254 patients (age: 56 +/- 14 years [mean +/- standard deviation], 181 female, 73 male) referred to a hospital for radioiodine treatment of hyperthyroidism or for follow-up of differentiated thyroid cancer, respectively, were included. All patients underwent the twelve-item general health questionnaire, which is an instrument for detecting mood disturbances. Euthyroid and hyperthyroid patients did not differ significantly in their general health questionnaire score (11 +/- 5 vs. 11 +/- 7), nor did subclinical hyperthyroid (11 +/- 6) or subclinical hypothyroid subjects (12 +/- 5). In contrast, hypothyroid patients showed a significantly higher mean score (17 +/- 7, p < 0.001, ANOVA). Binary logistic regression revealed that hypothyroidism increases age and gender-adjusted risk for critical mood deterioration by seven-fold. Thus, hypothyroidism represents a widely underestimated functional condition that may severely affect mental health.

Adult↗
PubMed2003

Psychological distress and socioeconomic status in single mothers and their children in a German city.

BACKGROUND: The proportion of single mothers in western countries is continuously growing. In contrast to other western countries, support programs in Germany especially for single mothers are rare. This study identifies for the first time in Germany within a large epidemiological sample different subgroups of higher distressed single mothers as important potential target groups for psychosocial support interventions. Facing limited resources, data about these subgroups are helpful to develop and establish specific support programs. METHOD: In a cross-section study, family status of a complete cohort of school beginners in Duesseldorf (N = 5178 children, aged 5-7 years) was screened within the school eligibility test (recruitment rate 97.5 %, N = 5048). Out of a total of 891 single mothers, 531 fulfilling inclusion criteria (speaking fluent German, not married, living together with the tested child, informed consent) were compared to a control group of married mothers out of the same sample (N = 278). Socioeconomic status, social network and psychological distress of mothers (SCL-90-R) and children (CBCL) were investigated. RESULTS: Socioeconomic status (income, education) of single mothers was lower while psychological distress (SCL-90-R) was elevated compared to the control group. Single mothers without additional personal support for their child, younger, as well as poor single mothers showed higher values of psychological distress. In sons of single mothers, increased behavior problems were found (CBCL). Of all children screened, 907 (18 %) lived in single-parent families. CONCLUSION: An increased psychological distress of single mothers and their sons could be shown for the first time in Germany within a large epidemiologic sample. This has implications for the planning of preventive interventions and evaluation of associations, e. g., between social variables and distress of single mothers and their children within longitudinal study designs.

Adult↗
PubMed2002

Relativity restored: Dirac anisotropy in QED3.

We show that, at long length scales and low energies and to leading order in 1/N expansion, the anisotropic QED in 2+1 dimensions renormalizes to an isotropic limit. Consequently, the (Euclidean) relativistic invariance of the theory is spontaneously restored at the isotropic critical point.

Journal Article↗
PubMed2002

Magnetic field induced charge and spin instabilities in cuprate superconductors.

A d-wave superconductor, subject to strong phase fluctuations, is known to suffer an antiferromagnetic instability closely related to the chiral symmetry breaking in ( 2+1)-dimensional quantum electrodynamics ( QED3). Based on this idea we formulate a " QED3 in a box" theory of local instabilities of a d-wave superconductor in the vicinity of a single pinned vortex undergoing quantum fluctuations. As a generic outcome we find an incommensurate 2D spin density wave forming in the neighborhood of a vortex with a concomitant "checkerboard" pattern in the local electronic density of states, in agreement with recent neutron scattering and tunneling spectroscopy measurements.

Journal Article↗
PubMed2002

[Quality criteria for psychosomatic consultation-liaison service].

Besides the integrated psychosomatic models in various medical specialities (e.g. Internal medicine, Obstetrics and Gynaecology or Paediatrics), specific models of cooperation in the form of consultation-liaison (C-L) service between specialised psychosomatic-psychotherapeutic departments and other medical departments play a crucial role in providing psychosomatic care to patients. The concept 'liaison' expresses a particularly close form of cooperative activity, going far beyond the classical model of consultation services. In this context, the psychosomatic consultant has not only a fixed organised presence in the provision of patient care, he/she also participates in case discussions, hospital rounds, ward discussions and continuing education programmes of the 'partner' department. Thus, the liaison service is not only patient-centred, but also team-centred. Such consultation-liaison services, in Austria, were first established at the University Hospitals. As a consequence of laws regulating psychotherapeutic care, according to which such care is to be offered in general hospitals, increasingly C-L services are becoming part of regular care provision in more and more hospitals. Consensus groups, international as well as in German-speaking countries, are currently working on establishing quality standards in the area of psychosomatic C-L services. A working group of the scientific medical representatives has recently published guidelines for the structure, process and results of quality control. A second group, of the European Association of Consultation Liaison Psychiatry and Psychosomatics, is currently working on guidelines for training consultation-liaison service providers. In the present article, an overview of these projects will be presented and the results discussed against the background of the specific health policy situation in Austria.

Austria↗
PubMed2001

Algebraic Fermi liquid from phase fluctuations: "topological" fermions, vortex "berryons," and QED3 theory of cuprate superconductors.

Within the phase fluctuation model for the pseudogap state of cuprate superconductors we identify a novel statistical "Berry phase" interaction between the nodal quasiparticles and fluctuating vortex-antivortex excitations. The effective action describing this model assumes the form of an anisotropic Euclidean quantum electrodynamics in (2+1) dimensions (QED (3)) and naturally generates non-Fermi liquid behavior for its fermionic excitations. The doping axis in the x -T phase diagram emerges as a quantum critical line which regulates the low energy fermiology.

Journal Article↗
PubMed2001

Primary structure, isoforms, and molecular modeling of a chitin-binding mistletoe lectin.

From mistletoe Viscum album L. extracts three chitin-binding lectin isoforms, cbML1, cbML2, and cbML3, were isolated and their primary structure determined. All three cbML isoforms are composed of two protein chains of 48 or 49 amino acid residues, linked by an intermolecular disulfide bond. The sequence of each single cbML chain is characterized by a relatively high number of cysteine and glycine residues, 9 and 6, respectively, and contains four intramolecular disulfide bridges. On the basis of the combined interpretation of sequencing and MALDI MS data, the following results for the three cbML isoforms were obtained: the first one consists of two identical truncated polypeptide chains (1--48), the second is a heterodimer, containing one truncated (1--48) and one full-length chain (1--49), and the third is composed of two full length chains (1--49). The cbML sequence shows 55% identity to hevein, a single-chain chitin-binding protein of 43 amino acids, one of the most predominant proteins in natural rubber latex. On the basis of the NMR data on hevein from Hevea brasiliensis the three-dimensional structure of cbML3 was modelled. The 26 sequence changes between cbML3 and hevein were accommodated with only little perturbation in the main chain folding. A comparison of the primary structures of cbML3 and hevein is shown and the effects of the sequence changes are discussed. Differences have been identified in the loop region of the molecule and the potential interface region of cbML3 supporting the dimer formation. The high-affinity chitin-binding site seems to be highly conserved.

Amino Acid Sequence↗
PubMed2001

N-terminal fragments of the proatrial natriuretic peptide in plasma and urine of kidney graft recipients.

BACKGROUND: Successful kidney transplantation normalizes elevated proatrial natriuretic peptide (proANP) plasma concentrations of renal failure patients in the early posttransplant period. We evaluated plasma and urinary proANP fragments in the late posttransplant period. METHODS: Immunoreactive proANP(1-30) and proANP(31-67) were determined in 389 renal transplant (Rtx) recipients in the long-term, follow-up period and in 16 healthy controls. RESULTS: Rtx recipients had significantly higher concentrations of proANP(1-30) and proANP(31-67) in both plasma and urine than healthy controls. Although their graft function was normal, all of these long-term Rtx recipients were taking glucocorticoids, which increase proANP(1-30) and proANP(31-67) in the circulation to the extent found in this investigation. Two-thirds of these recipients were also taking cyclosporine, which also increases atrial peptides. Urinary proANP(31-67) was significantly higher than urinary proANP(1-30); 5.5-fold in Rtx patients and 2-fold in controls. Deterioration of renal graft function was associated with a rise of plasma proANP(1-30) from 0.98+/-0.66 to 6.28+/-3.55 nmol/l (P<0.0001) and plasma proANP(31-67) from 1.81+/-1.04 to 7.89+/-3.76 nmol/l (P<0.0001). Urinary excretion of proANP(1-30) increased from 0.27+/-0.34 to 5.96+/-5.07 nmol/24 hr (P<0.0001) and proANP(31-67) from 1.45+/-0.85 to 12.23+/-5.12 nmol/24 hr (P<0.0001). Also proteinuria enhanced plasma and urinary proANP fragments. CONCLUSIONS: ProANP(1-30) and proANP(31-67) of Rtx recipients are affected by immunosuppression, hypertension, renal failure, and proteinuria. One would have expected proANP(1-30) and proANP(31-67) not to normalize because of the glucocorticoids that they were receiving.

Adult↗
PubMed2001

Treatment of alcohol withdrawal: tiapride and carbamazepine versus clomethiazole. A pilot study.

In Germany, clomethiazole (CLO) and benzodiazepines are predominantly used as therapeutic agents in the treatment of the alcohol withdrawal syndrome (AWS). These agents have disadvantages such as sedation, risk of respiratory insufficiency, and cardiovascular complications as well as addictive potential. Alternatively, it could be demonstrated that both tiapride (TIA) and carbamazepine (CBZ) are efficient in the treatment of AWS with less toxicity. However, they seem to be less effective in AWS than CLO as single agents. But no systematic comparison of the combination of TIA and CBZ against an established therapeutic standard can be found in the literature. Therefore, we compared the combination of TIA and CBZ with CLO in two open exploratory studies with matched samples. Outcome parameters were heart rate, blood pressure, complications, withdrawal symptoms (CIWA-Ar scale), and general clinical state (CGI scale). A retrospective evaluation of medical records (30 TIA+CBZ, 30 CLO) was followed by an open prospective study (40 TIA+CBZ, 40 CLO). Both studies revealed similar efficacy in terms of psychopathologic and vegetative symptoms. Vegetative recovery seems to be faster with TIA+CBZ. Results of this exploratory study have to be confirmed by a controlled double-blind study with severity of AWS as an experimental factor.

Adult↗
PubMed2001

Responsiveness of subjective quality of life assessment in schizophrenic patients: a quasi-experimental pilot study.

Responsiveness of quality of life (QOL) assessments in chronic schizophrenic patients was investigated by a quasi-experimental pilot study. Satisfaction ratings were assessed over five time points with an externally imposed disturbing stimulus at the second time point. Despite a markedly high stability, the disturbance provoked a temporally limited decrease in QOL.

Chronic Disease↗
PubMed2001

Plasma concentration and urinary excretion of N-terminal proatrial natriuretic peptides in patients with kidney diseases.

BACKGROUND: Biologically active N-terminal fragments such as proANP(1-30), proANP(31-67), and proANP(1-98) derive from the prohormone of alpha-human atrial natriuretic peptide [proANP(99-126) or alpha-ANP]. No systematic data are available for patients with different kidney diseases. METHODS: Specific immunoassays were developed to determine plasma and urine concentrations of these fragments in 121 patients with different degrees of kidney function and urinary protein excretion, respectively. RESULTS: In patients with kidney disease and normal renal function without proteinuria, circulating proANP(1-30) and proANP(31-67) increased 2.8-fold and 6.5-fold, respectively. Urinary excretion of proANP(31-67) increased by a factor of 7.7 in these patients, whereas proANP(1-30) was not affected. Patients with impaired renal function had a dramatic increase of urinary proANP(31-67) excretion even before serum creatinine levels started to rise. The progression of renal failure caused a significant rise of circulating proANP(1-30) (4.3-fold) and proANP(31-67) (3.0-fold) compared with patients with normal renal function. Urinary excretion of proANP peptides significantly increased, particularly when the serum creatinine level was> 5.0 mg/dL [proANP(1-30) 26-fold, proANP(31-67) 8.4-fold]. Urinary excretion of proANP(1-30) increased up to 4.4-fold and urinary excretion of proANP(31-67) increased up to 2.4-fold in patients with proteinuria in excess of 3 g/24 h. CONCLUSIONS: Plasma concentrations and urinary excretion of proANP(1-30) and proANP(31-67) are affected by kidney disease and function, but not by proteinuria per se. It is proposed that the diseased kidney increases early urinary excretion of proANP fragments to participate in the regulation of renal function as well as sodium and water excretion.

Adolescent↗
PubMed2001

Adsorption of natriuretic factors in uremia.

Patients with end-stage renal disease have a deranged sodium and water homeostasis leading to chronic volume overload. Atrial natriuretic peptides (ANPs) are circulating hormones that are involved in the regulation of volume homeostasis, blood pressure control, and electrolyte balance. In hemodialysis patients plasma ANPs are highly elevated and decrease during the dialysis session when fluid is removed. However, hemodialysis treatment never corrects the defect in the metabolism of these peptides and their circulating concentrations do not return to levels found in healthy controls. Besides uremia and chronic volume overload, other factors such as cardiac dysfunction or hypertension may contribute to the elevated plasma concentrations of ANPs. ProANP fragments which derive from the N-terminus of the ANP prohormone have been also found in the circulation and they have biological functions similar to alpha-ANP (ie, the C-terminus of the prohormone). The proANP peptides proANP(1-30), proANP(31-67), and proANP(1-98) are increased in patients undergoing regular hemodialysis treatment, but their decrease during the dialysis procedure is less pronounced than for alpha-ANP or cyclic GMP. Cellulose triacetate dialyzer membrane material lowered the plasma concentrations of proANP(1-30), proANP(31-67), and proANP(1-98) significantly more than polysulfone, whereas alpha-ANP and cyclic GMP were not differently affected. Aside from a variety of factors that influence circulating natriuretic factors in the uremic patient, there is evidence for differences in dialyzer membrane adsorption of these peptides which speculatively may be linked to dialysis-associated symptoms.

Adsorption↗