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Biomedical subjects

T Müller

Publications and source records attributed to T Müller.

At least 541 records · Page 30Linked to original sources
PubMedDate not supplied

Luminol-dependent chemiluminescence in bovine eosinophils and neutrophils: differential increase of intracellular and extracellular chemiluminescence induced by soluble stimulants.

Luminol chemiluminescence was used to detect activation of the respiratory burst oxidase in bovine eosinophils and neutrophils. Extracellular and intracellular chemiluminescence were measured by supplementing the medium with horseradish peroxidase and catalase, respectively. Pure bovine eosinophils (greater than 90%), maximally stimulated with 1 nmol/l phorbol 12-myristate-13-acetate (PMA) showed ten times more extracellular luminol-dependent chemiluminescence (CL) than maximally stimulated pure bovine neutrophils (greater than 96%). Extracellular CL from eosinophils was preferably induced over intracellular CL by both PMA (27-fold difference) and platelet-activating factor (PAF) at 2 mumol/l (9-fold difference), but not by calcium ionophore A23187 (15 mumol/l). Time course information was used in the following experiments to distinguish between the mode of action of various stimulants. A progressively longer lag period was observed in eosinophil suspensions treated with decreasing doses of PMA, whereas platelet-activating factor induced a dose-dependent increase in the maximum response with no change in time to peak CL. The time course of extracellular CL was almost identical to intracellular CL for all stimulants tested, providing no evidence to suggest that extracellular CL stems from a different enzyme system than intracellular CL. Eosinophils generated most extracellular CL when stimulated with PMA, whereas neutrophils were most efficiently stimulated with A23187, which induced intracellular CL in eosinophils as well as in neutrophils. This accords with the greater tendency of neutrophils to ingest and kill microorganisms, whereas eosinophils are armed to destroy large extracellular targets.

Animals↗
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Traveling-wave dielectrophoresis of microparticles.

The traveling-wave-induced linear transfer of dielectric particles like living cells and artificial objects of microscopic dimensions is analyzed. It is shown that the electrode geometries must correspond to particle sizes to allow an effective manipulation of particles immersed in weakly electrolytic solutions by high frequency traveling waves. The theoretical model elaborated in this paper is in good agreement with experimental results obtained in microfabricated chambers of linearly arranged electrodes. It explains the behavior of homogeneous cellulose spheres as well as that of membrane-covered pine polls. The traveling-wave-driven electrodes are described by a superposition of time-dependent point charges. Subsequently, each of these point charges has to be considered as polarizing the dielectric particle and interacting with the polarized particle. This results in forces which effectively translocate the particle.

Cellulose↗
PubMedDate not supplied

Imaging the asymmetrical DNA bend induced by repressor activator protein 1 with scanning tunneling microscopy.

The yeast Repressor Activator Protein 1 (RAP1) binds a 13-bp consensus found in many transcriptional regulatory regions, in silencer elements, and in telomeric repeat DNA of Saccharomyces cerevisiae. Gel retardation assays suggest that RAP1 bends DNA as it binds, with the vertex of the angle located 5' of the consensus. We show that removal of 230 aa in the N-terminus of RAP1 reduces the aberrant electrophoretic mobility of the protein-DNA complex, while removal of a C-terminal domain of RAP1 causes even greater distortion. To demonstrate that the aberrant electrophoretic mobility is really due to a bend in the double helix, the RAP1-DNA complex was analyzed by Scanning Tunnelling Microscopy (STM). The efficiency and accuracy of binding is checked in parallel by standard Transmission Electron Microscopy (TEM). Due to the use of high-angle shadowing of freeze-dried samples at low temperatures, the STM images allow us to confirm that RAP1 binding induces a DNA bend > 50 degrees, while the binding of the minimal DNA-binding domain shows significantly less distortion of the DNA helix.

DNA↗
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Hormonal induction of functional differentiation and mammary-derived growth inhibitor expression in cultured mouse mammary gland explants.

A method for the cultivation of organ explants from abdominal mammary glands of virgin mice has been established. In a serum-free medium containing aldosterone, prolactin, insulin, and cortisol (APIH medium) mammary gland development was documented by lobuloalveolar morphogenesis. The hormonal requirements for in vitro expression of beta-casein and of the mammary-derived growth inhibitor (MDGI) were tested. To this end, a full length cDNA coding for mouse MDGI was prepared displaying strong homologies to a mouse heart fatty acid binding protein, which is also expressed in the mammary gland. MDGI and beta-casein transcripts were found to be absent in the mammary tissue from primed virgin mice, and were induced upon culture of mammary explants in the APIH medium. An immunohistochemical analysis with specific antibodies against MDGI and casein revealed a different pattern of expression for the two proteins. In the APIH medium, MDGI was expressed mainly in differentiating alveolar cells of the lobuloalveolar structures, whereas beta-casein was present in both ductules and alveoli. The relationship between functional differentiation and MDGI expression was further studied in explants from glands of late-pregnant mice. At this stage of development, MDGI is found both in ducts and in alveoli. If explants were cultured with epidermal growth factor (EGF) and insulin, the lobuloalveolar structure was still present, whereas MDGI disappeared. Reinduction of MDGI expression was achieved by subsequent PIH treatment. Independent on developmental stage, EGF strongly inhibits MDGI mRNA expression. It is concluded that MDGI-expression is associated with functional differentiation in the normal gland.

Aldosterone↗
PubMedDate not supplied

Expression of BCL-2 in liver grafts after adenoviral transfer improves survival following prolonged ischemia and reperfusion in rat liver transplantation.

UNLABELLED: Apoptosis represents a crucial mechanism of ischemia-reperfusion injury after liver transplantation. Bcl-2 may inhibit apoptosis. This study investigates the effect on ischemia/reperfusion injury and survival after rat liver transplantation of adenoviral bcl-2 transfer into donor livers. METHODS: A nonreplicative adenovirus, expressing bcl-2 under control of a tetracyclin-inducible promoter (adv TetOn bcl-2) was used to treat male Lewis rats in combination with a second adenovirus transferring the TetOn repressor protein under control of a cytomegalovirus promoter (advCMVRep). Virus induction was achieved by addition of doxycyclin to the drinking water. Controls were pretreated with a control adenovirus (advCMV GFP) or with doxycycline. Liver transplantations were performed after 16-hour graft storage. Bcl-2 expression was evaluated by Western blot and immunohistology. Survival was monitored for 7 days, and tissue specimens were collected at 24 hours and 7 days post reperfusion. RESULTS: After pretreatment with advTetOn bcl-2/adv CMVRep, intrahepatic bcl-2 expression was evident at 24 hours and 7 days but was absent among controls. Bcl-2 expression was detected in hepatocytes and, to a high degree, in sinusoidal lining cells. TUNEL-positive sinusoidal lining cells were strikingly reduced after bcl-2 transfer (0.1 +/- 0.3 cells/hpf, mean +/- SD) compared to control virus (4.8 +/- 2.3) or doxycyclin-treated grafts (1.3 +/- 0.2); P < .05. After bcl-2 treatment, survival after transplantation was 100%, whereas it was 50% in both control groups (P = .035). CONCLUSION: The study shows the feasibility of transient, doxycyclin-controlled adenoviral gene transfer in a transplantation model. Bcl-2 expression increased survival after ischemia/reperfusion in rat liver transplantation, potentially through protection of sinusoidal lining cells.

Adenoviridae↗
PubMedDate not supplied

Developmental changes in the complexity of the electrocortical activity in foetal sheep.

The foetal sheep brain develops organised sleep states from 115-120 d gestational age (dGA, term 150 dGA) alternating between REM and NREM sleep. We aimed to investigate whether maturation of REM or NREM sleep generating structures leads to the development of distinct sleep states. The electrocorticogram (ECoG) was recorded from five unanaesthetised chronically instrumented foetal sheep in utero and was analysed every 5th day between 115-130 dGA by two different non-linear methods. We calculated a non-linear prediction error which quantifies the causality of the ECoG and applied bispectral analysis which quantifies non-linear interrelations of single frequency components within the ECoG signal. The prediction error during REM sleep was significantly higher than during NREM sleep at each investigated age (P<0.0001) coincidental with poor organisation of the rhythmic pattern in the ECoG during REM sleep. At 115 dGA, organised sleep states defined behaviourally were not developed yet. The prediction error, however, showed already different states of electrocortical activity that were not detectable using power spectral analysis. The prediction error of the premature NREM sleep ECoG decreased significantly during emergence of organised sleep states between 115 and 120 dGA and continued to decrease after the emergence of distinct sleep states (P<0.05). The prediction error of the premature REM sleep ECoG did not change until 120 dGA and began to increase at 125 dGA (P<0.05). Using bispectral analysis, we showed couplings between delta waves (1.5-4 Hz) and frequencies in the range of spindle waves (4-8 and 8-12 Hz) during NREM sleep that became closer during development. The results show that maturation of ECoG synchronisation mediating structures is important for the development of organised sleep states. The further divergence of the prediction error of NREM and REM sleep after development of organised sleep states reveals continuous functional development. Thus, complementary application of non-linear ECoG analysis to power spectral analysis provide new insights in the collective behaviour of the neuronal network during the emergence of sleep states.

Algorithms↗
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Endemic Tyrolean infantile cirrhosis is not an allelic variant of Wilson's disease.

Recently, 138 cases of infantile cirrhosis originating in several families in the Austrian province of the Tyrol were reported. This endemic Tyrolean infantile cirrhosis (ETIC) is indistinguishable from Indian childhood cirrhosis (ICC), idiopathic copper toxicosis (ICT), and resembles the early forms of Wilson's disease (WND). It has been argued that ETIC might represent an allelic variant of the WND gene, which is a copper transporting P-type ATPase (ATP7B). Assuming that ETIC results from a founder effect, a possible role for ATP7B in ETIC was investigated by association studies and haplotype sharing. Because of its lethality, the mapping of ETIC was focused on obligate gene carriers, i.e. the patients' parents. Our data indicate that ETIC is a separate genetic entity, distinct from WND.

Age of Onset↗
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[Diagnostic and therapeutic proceedings in pregnancies with blood group incompatibility: A retrospective analysis over 30 years].

PURPOSE: To examine the development during the past 30 years of diagnostic and therapeutic procedures in pregnancies with blood group incompatibility. PATIENTS AND METHODS: We evaluated 193 pregnancies with maternal red blood alloimmunisation treated at our hospital. At least one amniotic fluid spectrophotometry was performed. RESULTS: We observed a reduced average age of the patients, a reduced parity and an increase in the number of amniotic fluid examinations per pregnancy in the course of time. Amniotic fluid examinations tended to be performed earlier in pregnancy. Gestational time was reduced, the rate of spontaneous vaginal deliveries remained unchanged. The proportion of anti-D-alloimmunisation decreased in relation to other antigens and the severity of the cases increased (assessed according to the findings of the spectrophotometric amniotic fluid examinations performed while using the semiquantitative method of Liley). The haemoglobin values of the newborn, without intrauterine transfusions, were unchanged and the number of intrauterine deaths decreased. The rate of postnatal transfusions decreased dramatically, whereas the rate of phototherapeutic approaches increased. CONCLUSION: The spectrum of the antigens causing fetal haemolytic disease has changed during the last 30 years and so have the diagnostic and therapeutic procedures.

Adolescent↗
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[Ovarian epidermoid cyst and endometrioid carcinoma: do they share their origin?].

A case of a well differentiated endometrioid adenocarcinoma of the ovary in combination with an epidermoid cyst is described. A typical epidermoid cyst without skin appendages could be observed. In direct neighborhood, there was a typical endometrioid carcinoma with some foci of squamous metaplasia. There was no continuum between the squamous metaplasia of the carcinoma and the wall of the epidermoid cyst. In addition, the benign cyst and the carcinoma shared some of their immunohistochemical profile. This case highlights the still unsolved question about the origin of epidermoid cysts and adds to the hypothesis that they arise from pluripotent coelomic epithelium.

Endometrial Neoplasms↗
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Impact of three-dimensionally measured endometrial volume on the pregnancy rate after intrauterine insemination.

OBJECTIVE: The success of artificial reproductive techniques not only depends on the quality of oocytes and spermatozoa but also on the receptivity of the endometrium. The aim of this study was to assess the role of endometrial volume measurement by three-dimensional ultrasound in predicting the pregnancy rate (PR) in women receiving controlled ovarian hyperstimulation followed by intrauterine insemination. MATERIAL AND METHODS: 104 patients having intrauterine insemination (IUI) were included in this prospective trial. Ovarian hyperstimulation was performed with gonadotropins in 73 % of patients and with clomiphene citrate (CC) in 27 % of patients. Endometrial thickness, pattern and three-dimensional volume were measured immediately before insemination. RESULTS: In 104 IUI cycles a total of 14 clinical pregnancies were recorded (PR=13.5 %). The endometrial volume was 3.5 ml and was not significantly different in pregnant (4.0 +/- 1.5 ml) from non-pregnant women (3.4 +/- 1.9 ml). In the subgroup of women with an endometrial volume > or = 2 ml and trilaminar endometrium the pregnancy rate was 22 %, significantly higher than that in women without these two criteria (PR 6 %, p < 0.05). The negative predictive value of an endometrial volume < 2 ml for a clinical pregnancy after IUI was 96 %. Endometrial volume and thickness were significantly higher after ovarian hyperstimulation with gonadotropins (3.7 ml and 11.0 mm) than with CC (2.8 ml and 9.5 mm; p < 0.05). CONCLUSIONS: An endometrial volume < 2 ml at the day of insemination is associated with a poor likelihood of pregnancy. Endometrial volume measured by 3D ultrasound is a new objective parameter to predict endometrial receptivity.

Adult↗
PubMedDate not supplied

[Complex reconstruction of subluxated and dislocated hip joints in spastically handicapped children].

QUESTION: Will surgical reconstruction of subluxated or dislocated hip joints in children with cerebral palsy lead to stable reduction and painless hips? Is there any positive influence on psychomotoric development of the children and on trunk and pelvic symmetry as well as on daily hygienic care after successful reduction of unstable hip joints in spastic children? MATERIALS AND METHODS: Thirty hip joints in 26 children with cerebral palsy were operated applying the same complex reconstruction method of the hip joint. Fifteen of these children with 17 operated hip joints fulfilled a minimum follow up period of 3 years were evaluated continuously in this study. The parents and physiotherapists answered a questionnaire, all patients were examined clinically and pelvic anteroposterior and lateral radiographs were obtained. RESULTS: The mean age at surgery was 6 years, the minimum follow up 3 years (3-10 years). All hip joints were preoperatively decentered, 6 subluxated, 11 complete dislocated. At follow-up 15 of 17 were persistently reduced. The postoperative results were graded by the parents as excellent and good in eleven, satisfying in four and in two patients as poor. The radiographic evaluation showed an significant improvement of the CE-, AC- and neck shaft angle. CONCLUSION: Reconstruction of decentered hips will lead to stable reduction and painless hips at least in mid term follow-up. Symmetrically centered hip joints are mandatory for a pelvic and spinal symmetry and may contribute for an optimal of psychomotoric development.

Cerebral Palsy↗
PubMedDate not supplied

[Correlation of the degeneration of the AC joint (acromioclavicular) and rupture of the rotator cuff].

During the past various factors were quoted to be causative of a degeneration of the rotator cuff. In this study 122 shoulder specimen, aged 58-95 years, were dissected. A high correlation between severe degeneration of the ac-joint and rupture of the rotator cuff was found. The correlation was even higher between distally pointing osteophytes and cuff ruptures. The results demand to clearly define the degeneration of the ac-joint and the rotator cuff in patients suffering from shoulder pain. A simultaneous occurrence has to be considered. If conservative treatment fails in patients with cuff tear and ac-joint degeneration, surgical revision is recommended. This should comprise: 1. suture of the cuff-rupture 2. excision of the coraco-acromial ligament 3. anterior acromioplasty according to Neer 4. excision of the outer end of the clavicle

Acromioclavicular Joint↗
PubMedDate not supplied

[Formula creatinine clearance as a substitute for 24-hour creatine clearance in children with kidney transplantation].

Despite many theoretical advantages, formula-creatininclearance (Schwartz et al, Journal of Pediatrics 1976) has not found broad clinical acceptance in everyday pediatric patient care. In this study we report our results of long term observations (11.7 +/- 6.8 (1.7-24.8) months) of measured and computed creatininclearance in 27 children after renal transplantation (15 boys, 12 girls, mean age 14.5 +/- 4.2 (5.5-20) years) at the Kinderdialyse of the Universitäts-Kinderklinik of Vienna. We found a wide scattered correlation between the measured and computed creatininclearance values with a 90% confidence interval between -30% to +60% of the 24 hour creatininclearance. Formula creatininclearance (SD 17.8%) was markedly better reproducable than the 24 hour creatininclearancethe (SD 37.8%), the intraindividuell collecting error (36.1%) was almost twice the interindividuell "coefficient" error (20.27%). We therefore conclude that the 24 hour creatininclearance is by far not as accurate as the complexity of the procedure pretends and support broad clinical acceptance for the formula creatininclearance.

Adolescent↗
PubMedDate not supplied

The neuroimmune hypothesis in Parkinson's disease.

The role of immune mechanisms in the pathogenesis of Parkinson's disease is still a matter of controversy. Immunological abnormalities have been reported in various brain areas and in peripheral immune parameters. Beside antigen specific findings which might indicate an autoimmune process directed against dopaminergic neurons, non-antigen specific abnormalities have been found, which could be caused either by a disease specific process and/or by immunological properties of various anti-parkinsonian drugs, e.g. bromocriptine. Immune reactions may imitate or maintain the degenerative process. In this case possible neuroprotective strategies interfering with immune functions could be developed. Further investigations are necessary to elucidate the impact of immune mechanisms on the degenerative process in Parkinson's disease.

Animals↗
PubMedDate not supplied

[Effect of methods of sterilization on thermoplastics with special reference to modified surfaces].

For materials intended for use in the medical setting their sterilizability is an indispensable prerequisite. In the case of most polymers the usual sterilization methods result in changes that even extend to cleavage of the polymer chains. A particular problem in this respect are the surfaces modified for improved biocompatibility investigated in the present study, which are characterised by enlarged contact areas. For this reason, possible changes to three different thermoplastics commonly used for medical applications (polyethylene, thermoplastic polyurethane, polycarbonate) were investigated. Steam, gas and radiation were used for sterilization. Tensile tests were employed to identify changes in mucosal characteristics caused by different sterilization techniques irrespective of the surface modification. Sterilization-related changes to the structure of the modified surfaces were investigated with the scanning electron microscope (SEM). Differential thermo analysis (DTA) was used to determine changes in the thermal characteristics of the plastics. Clear tendencies with regard to the behaviour of the plastics after sterilization with various techniques were found. A general statement about the compatibility of plastic materials with a specific sterilization method is not possible on the basis of this study. For every new polymeric product used for medical purposes, the characteristics required must first be defined and compliance with the permissible variations of these characteristics investigated for each of the various sterilization techniques available.

Equipment Failure Analysis↗
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A descriptive analysis of the potential association between migration patterns of bean and white-fronted geese and the occurrence of Newcastle disease outbreaks in domestic birds.

The sightings and migration patterns of 65 bean (Anser fabalis) and 65 white-fronted geese (Anser albifrons) are reported. In the past, these geese were serologically screened for the occurrence of Newcastle disease virus (NDV) and other avian viral diseases by Hlinak et al. (3). Of the 130 birds originally tagged and serologically screened in 1991, 53 birds were resighted between 1991 and 1996. Most of the sightings were reported from main wintering and resting sites in Germany and The Netherlands. It is noteworthy that 19 of the 53 birds sighted had serologic evidence that they had been exposed to NDV before the time of marking in 1991. Although the origin of these infections in bean geese and white-fronted geese is still unknown, the sightings reported in this study indicate that, once infected, wild geese may be involved in the dissemination and spread of avian viral diseases, specifically Newcastle disease. The migration patterns of the wild geese provided further evidence that the main resting and wintering areas of migratory waterfowl are likely to be important for the inter- and intraspecies transmission of avian diseases, thereby representing risk areas for the poultry industry.

Animals↗