Biomedical subjects

M Pichler

Publications and source records attributed to M Pichler.

At least 19 recordsLinked to original sources

PubMed2006

Simultaneous angiographic imaging of ipsilateral pulmonary veins for catheter ablation of atrial fibrillation.

Various imaging techniques are nowadays in clinical use to obtain important information about pulmonary vein (PV) anatomy in patients undergoing catheter ablation of atrial fibrillation (AF). Although some controversy exists about the optimal approach for catheter ablation of AF in recent times, knowledge of the individual left atrial-PV anatomy remains a basic feature of the different ablational techniques. Angiographic delineation of PV ostia has become an integral part of the PV isolation procedure, mainly in order to avoid potentially harmful PV stenosis. Selective venography with angiocatheters is well documented and widely available but has its own limitations, particularly with respect to visualization of the atriovenous junctions. The present report summarizes the usefulness, safety and feasibility of a new angiographic technique for simultaneous imaging of ipsilateral PVs applicable during catheter ablation of AF. Electrophysiologically guided segmental PV isolation was accomplished in 31 patients mostly with paroxysmal atrial fibrillation, who experienced significant clinical improvement during a followup of 17 +/- 15 months. The angiographic technique was effective for assessment of the individual anatomy including common ostia and supernumerary veins which can be easily missed by selective venography. Variant PV ostia were identified in about 20% of patients; particularly the presence of a left common trunk was challenging for the segmental ablation strategy. Angiographic detection of variant PV anatomy was comparable to visualization with computer tomography performed at 4-months follow-up. Finally, this type of angiographic imaging performed at the time of catheter ablation may help to reduce the risk of significant PV stenosis.

Adult↗

PubMed2005

Relationship of QT interval duration with carotid intima media thickness in a clinically healthy population undergoing cardiovascular risk screening.

OBJECTIVES: To investigate the relationship between cardiac repolarization (QT interval duration) and intima media thickness (IMT) of the carotid arteries as surrogate measures of subclinical atherosclerosis. DESIGN: Prospective study with consecutive subjects enrolled in the SAPHIR program (Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk). SETTING: The analysis of the material was performed at the departments of medicine and neurology of a university hospital. SUBJECTS: The study cohort comprises a population-based sample of 1199 clinically healthy subjects (851 men and 348 women; age 39-66 years). Exclusion criteria were cardiovascular disease, diabetes, atrial fibrillation, bundle branch block and use of medication affecting QT interval duration. MAIN OUTCOME MEASURES: IMT of common (CCA) and internal carotid arteries (ICA) was measured by B-mode ultrasound. QT interval duration was determined in the resting 12-lead electrocardiogram by an automatic analysis program. The QT intervals were corrected for heart rate with five standard equations (QTc-Bazett, -Fridericia, -Framingham, -Hodges and -Rautaharju) and tested for their relationship with carotid IMT after adjustment for clinical and metabolic variables. Results. Females had higher heart rates than males (64 +/- 10 b min(-1) vs. 60 +/- 9 b min(-1), P <0.0005), with longer mean QT (410 +/- 28 ms vs. 404 +/- 28 ms, P=0.003) and QTc intervals in all correction formulae (P <0.0005). Significant correlations between QT/QTc and ICA IMT (r=0.14-0.16) were found in males. In the general linear model the association between QTc (except for Bazett) and ICA IMT remained significant after adjusting for age, BMI and further cardiovascular risk factors. In females the crude correlations between QT/QTc and ICA IMT were lower than those with CCA IMT. Only the correlation between uncorrected QT and CCA IMT (r=0.15, P=0.006) remained significant after adjustment for covariates. CONCLUSIONS: The results of the present study demonstrate that QT and QTc prolongation are in part associated with IMT of carotid arteries, which is an established risk marker of subclinical atherosclerosis. In men the data support the hypothesis of an association between QTc and ICA IMT. In women a statistically significant relationship was found between the uncorrected QT interval and CCA IMT. These findings suggest that differences in carotid IMT and ventricular repolarization between genders might be related to hormonal and nonhormonal effects.

Adult↗

PubMed2004

[Eyebrow injuries. Classification and therapy concept].

The aim of primary treatment for eyebrow injuries should be preservation of the original eyebrow under any circumstances. Debridement should be kept to a minimum even when the wound is severe. The treatment of total or partial loss of an eyebrow concerning the exact reconstruction of details and aesthetic aspects is a challenge for the surgeon. The therapy option depends on the type of eyebrow selected for reconstruction. We present a classification for eyebrow injuries, which considers type and size of defects. Based on this, different techniques and methods of reconstruction are recommended. Advantages and disadvantages are discussed and illustrated by several examples.

Eye Injuries↗

PubMed2003

The venous drainage of the lunate bone.

One of the theories as to the etiology and pathogenesis of lunatomalacia (Kienböck's disease) is based on the presentation of an osseous compartment syndrome caused by a venous block in the pedicle. This gave us cause to examine the lunate bone more closely and to investigate possible anatomical causes for the disruption. For this purpose, ten hands were removed from cadavers proximal to the radiocarpal articular space. Through an artificial intraosseous canal, which did not touch the vascular structures of the lunate bone, epoxy could be injected under controlled conditions. The venous drainage, from the exit out of the bones up to the entrance into the comitant veins of the distal forearm, was exposed as a preparation under the microscope. In all preparations a dense plexus of small venous vessels was found at the palmar and dorsal periosteal face which has not previously been described in literature. As this wide plexus is woven into the solid palmar as well as into the dorsal connective tissue, it could be, as we suppose, the weak point of the venous drainage we have been looking for. It is easy to imagine that the rheological situation in this venous segment is impaired and an osseous compartment syndrome is induced by systemic factors as well as by local compression.

Aged↗

PubMed2001

Persistent adenoviral infection and chronic obstructive bronchitis in children: is there a link?

Chronic obstructive bronchitis with inadequate response to inhaled steroid and bronchodilator therapy is a rather rare disorder in children. Persistence of an adenoviral infection has been described as a possible cause of unremitting airway obstruction. We studied a group of 11 children with the clinical feature of chronic bronchial obstruction. A high-resolution computed tomography (HR-CT) scan was performed and typically showed hyperinflation and ground-glass-like opacities. All children underwent either bronchoscopic transbronchial or open lung biopsy. Biopsy specimens were stained with monoclonal antibodies detecting adenoviral antigen and analyzed by light-microscopy. Bronchoalveolar lavage (BAL) fluid was cultured for adenovirus, and antigen detection tests were performed. While some children had a history of proven adenoviral infection at the onset of their disease, in none of the cases could a persistence of adenovirus be shown. We conclude that adenoviral infection might act as a starter of chronic obstructive bronchitis in children, but that pathogenetic mechanisms other than persistent infection must be responsible for the chronicity of the disease.

Adenoviridae Infections↗

PubMed2001

Solid-state (13)C NMR spectroscopic, chemolytic and biological assessment of pretreated municipal solid waste.

In Central Europe, composting and anaerobic digestion of municipal solid waste (MSW) is used as pretreatment before landfilling to reduce landfill emissions. MSW samples were analyzed before, during, and after pretreatment to assess the stability of the organic matter. Chemolytic, nuclear magnetic resonance (NMR) spectroscopic, and respiration parameters were correlated to evaluate a substitution of the time-consuming respiration analysis by chemical parameters. (13)C cross polarization magic angle spinning (CPMAS) NMR spectroscopy showed a preferential biodegradation of O-alkyl carbon (carbohydrates) and a selective accumulation of plastics during all pretreatments, confirming findings from chemolytic analyses. Principal component analysis exhibited a strong association between the respiration rate, the carbohydrate content, and the O-alkyl C content, corroborating that carbohydrates are the most important compounds of MSW with regard to the emission potential. Rank correlation (Spearman) also showed strong relationships between the respiration rate and the content of carbohydrates (r=0.75) and of O-alkyl C (r=0.72).

Journal Article↗

PubMed2000

Spontaneous and oxidative stress-induced programmed cell death in lymphocytes from patients with ataxia telangiectasia (AT).

T cell lymphopenia in the peripheral blood lymphocytes (PBL) of patients with AT is mainly caused by a decrease of naive CD45RA+/CD4+ cells followed by a predominance of memory CD45RO+ lymphocytes. To relate these findings to the regulation of programmed cell death, we investigated the activation state and apoptotic level of PBL in 12 patients and healthy controls by flow cytometry. In accordance with previous investigations, the number of naive CD4+/CD45RA+ cells was significantly decreased in patients compared with healthy controls. This disturbed balance of CD45RA and CD45RO was also reflected in higher amounts of activated HLA-DR and CD95 expressing cells, with a concomitant decrease of Bcl-2 protected lymphocytes in the T cell population. With regard to its role in preventing oxidative-induced cell death, we analysed Bcl-2 expression and apoptosis in the presence of oxidative stress. In culture, cells of patients are more susceptible to spontaneous programmed cell death. However, in our stress-inducing system (hypoxanthine/xanthine oxidase system) the number of cells undergoing apoptosis was lower in patients' cell populations compared with controls. In addition, preliminary results suggest that Bcl-2 expression and level of spontaneous apoptosis in patients can be modified by IL-2 and interferon-gamma.

Adolescent↗

PubMed1999

[Secondary prevention following coronary intervention. Survey of 13 intervention centers in Austria].

Risk factor control has been shown to reduce the incidence of coronary events in patients with or without preceding infarction. Secondary prevention should therefore be borne in mind by every cardiologist. In order to test this concept and/or to promote secondary prevention in our country, the following survey was conducted by our working group for epidemiology and prevention. All interventional centres of the country (7 million inhabitants) were asked to report relevant data of 50 consecutive patients with PTCA in a structured questionnaire. Thirteen centres responded and we report the data of 650 patients. The mean proportion of women was 28%, the mean age 61.1 years and the mean stent rate 49.8%. The indications for PTCA varied widely: stable angina 10-74%, unstable angina 10-86%, primary PTCA 0-22%. The risk factor history was distributed as follows: diabetes 12-46% (mean 22.3%), hypertension 32-68% (mean 54.2%), current smoking 6-56% (mean 21.9%), and total cholesterol (TChol) > 200 mg/dl: 30-78% (mean 60.3%). Current lipid values were available for T chol. in 44-100% (mean 84.5%) and for LDL in 4-100% (mean 67.1%). Dietary counselling by a dietician was done in 4-100% of patients (mean 35.6%) Information concerning the hazards of smoking was given to 25-100% (mean 83.6%) of current smokers. Drug treatment at hospital discharge was as follows: 84-100% (mean 93.1%) received ASA, 24-74% (mean 49.8%) ticlopidine, 6-84% (mean 53.3%) nitrates, 34-82% (mean 60.2%) beta blockers, 10-70% (mean 39.5%) ACE inhibitors, 4-74% (mean 4 7.2%) lipid lowering drugs, 7-48% (mean 17.8%) calcium antagonists, 0-12% (mean 6.1%) digitalis and 0-28% (mean 13.6%) diuretics. Follow-up data were collected in 4 centres at 6 months post discharge and were available for 174 patients. Here we found an increase in the prescription of calcium antagonists, digitalis and statins. The following conclusions were drawn at a conference in which all centres participated: lipid values should be available for each patient at PTCA, dietary counselling should be initiated for every patient during hospitalisation (and continued by the family physician) and the national cardiac society should promote guidelines for the use of drugs in which the variation in use is too wide at present. It should be ensured that these guidelines are implemented not only in patients after AMI but also in those after PTCA.

Adrenergic beta-Antagonists↗

PubMed1999

Relationship between natriuretic peptides and hemodynamics in patients with heart failure at rest and after ergometric exercise.

Sixteen patients with heart failure who underwent right heart catherization were studied with regard to plasma natriuretic peptide levels and hemodynamic parameters at rest and immediately after symptom-limited ergometry. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were measured and correlated with left ventricular ejection fraction (LVEF), mean pulmonary arterial pressure (MPAP), pulmonary arterial wedge pressure (PAWP) and cardiac index (CI). Compared to normal controls, ANP and BNP were elevated at rest. During exercise ANP and BNP increased. BNP was highly significantly correlated with LVEF (P = 0.005) at rest, whereas ANP did not (P = 0.082). BNP significantly correlated with MPAP and PAWP after exercise and showed a significant inverse correlation with CI. Our data provide evidence that BNP might be a better indicator for LVEF at rest than ANP. In addition, BNP correlates very well with MPAP and PAWP, after exercise. This close correlation is likely to reflect a correlation of BNP with left ventricular enddistolic pressure in heart failure when patients are exposed to physical exercise.

Atrial Natriuretic Factor↗

PubMed1999

Newer portable glucose meters--analytical improvement compared with previous generation devices?

BACKGROUND: Newer glucose meters are easier to use, but direct comparisons with older instruments are lacking. We wished to compare analytical performances of four new and four previous generation meters. METHODS: On average, 248 glucose measurements were performed with two of each brand of meter on capillary blood samples from diabetic patients attending our outpatient clinic. Two to three different lots of strips were used. All measurements were performed by one experienced technician, using blood from the same sample for the meters and the comparison method (Beckman Analyzer 2). Results were evaluated by analysis of clinical relevance using the percentage of values within a maximum deviation of 5% from the reference value, by the method of residuals, by error grid analysis, and by the CVs for measurements in series. RESULTS: Altogether, 1987 blood glucose values were obtained with meters compared with the reference values. By error grid analysis, the newer devices gave more accurate results without significant differences within the group (zone A, 98-98.5%). Except for the One Touch II (zone A, 98.5%), the other older devices were less exact (zone A, 87-92.5%), which was also true for all other evaluation procedures. CONCLUSIONS: New generation blood glucose meters are not only smaller and more aesthetically appealing but are more accurate compared with previous generation devices except the One Touch II. The performance of the newer meters improved but did not meet the goals of the latest American Diabetes Association recommendations in the hands of an experienced operator.

Ambulatory Care↗

PubMed1998

Insertion/deletion polymorphism in the angiotensin-converting enzyme gene is associated with atrial natriuretic peptide activity after exercise.

An insertion/deletion polymorphism in the gene coding for the angiotensin-converting enzyme (ACE) is strongly associated with ACE activity. This polymorphism may be a marker for an increased risk for cardiovascular events. Our study examined a possible relationship between the D/I polymorphism and myocardial release of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Ninety-six individuals with normal or impaired left ventricular function were included in the study. ANP and BNP plasma levels were measured at rest and after exposure to physical stress. At rest no association of ACE genotypes with ANP and BNP was found. After exercise homozygotes with the genotype DD had significantly higher ANP plasma levels than homozygotes with the genotype II. In contrast to ANP, BNP levels were not significantly different between genotype groups after exercise. Differences in site of production and mode of release between ANP and BNP might explain this difference. We hypothesize that our result might represent a variability gene effect of the ACE gene locus on endocrine processes in the heart during exposure to physical stress.

Adult↗

PubMed1997

Beta subunit heterogeneity in neuronal L-type Ca2+ channels.

Heterologous expression studies have shown that the activity of voltage-gated Ca2+ channels is regulated by their beta subunits in a beta subunit isoform-specific manner. In this study we therefore investigated if one or several beta subunit isoforms associate with L-type Ca2+ channels in different regions of mammalian brain. All four beta subunit isoforms (beta1b, beta2, beta3, and beta4) are expressed in cerebral cortex as shown in immunoblots. Immunoprecipitation of (+)-[3H]isradipine-labeled L-type channels revealed that the majority of beta subunit-associated L-type channels was associated with beta3 (42 +/- 8%) and beta4 (42 +/- 7%) subunits, whereas beta1b and beta2 were present in a smaller fraction of channel complexes. beta3 and beta4 were also the major L-type channel beta subunits in hippocampus. In cerebellum beta1b, beta2, and beta3 but not beta4 subunits were expressed at lower levels than in cortex. Accordingly, beta4 was the most prominent beta subunit in cerebellar L-type channels. This beta subunit composition was very similar to the one determined for 125I-omega-conotoxin-GVIA-labeled N-type and 125I-omega-conotoxin-MVIIC-labeled P/Q-type channel complexes in cerebral cortex and cerebellum. Our data show that all four beta subunit isoforms associate with L-type Ca2+ channels in mammalian brain. This beta subunit heterogeneity may play an important role for the fine tuning of L-type channel function and modulation in neurons.

Animals↗

PubMed1997

[Pathophysiological mechanisms of the renin-angiotensin system and its pharmacologic modification by ACE inhibitors or angiotensin II (type 1) receptor blockers in cardiovascular diseases].

As a net effect of ACE-inhibitors and AT1-receptor antagonists on the renin-angiotensin system (RAS) cardioprotection due to vasodilative (reduction of blood pressure, afterload reduction), antiproliferative (reduced cell growth, reduction of "vascular" and/or "ventricular remodeling", reduced formation of extracellular matrix), as well as antiadrenergic actions and due to the stimulating effect on natriuresis, reduction of blood pressure, preload reduction can be expected. These aims of therapy have mostly been confirmed for the action of ACE-inhibitors by experimental and clinical studies but except for the treatment of arterial hypertension and few preliminary reports concerning the treatment of cardiac dysfunction, no comparable data are available for AT1-receptor antagonists. To date, an antithrombotic and profibrinolytic action could only be demonstrated for ACE-inhibitors. This effect has been discussed to be responsible for the improvement of long-term prognosis in patients with coronary artery disease. Despite the similar spectrum of action there exist important differences between ACE-inhibitors and AT1-receptor antagonists that might underline the need of an individual use of these drugs: the dual action of ACE-inhibitors on the RAS and the kinin system bears many benefits but has been also shown to be accompanied by side-effects, mainly chronic dry cough, in a relatively high percentage of patients thus leading to discontinuation of therapy in 8-14%. This respective side-effect can be prevented by the use of AT1-receptor antagonists. It has been discussed whether the incomplete action of ACE-inhibitors on AT1-receptor-mediated effects is at least in part responsible for the efficacy of this drug which is relatively high (75-80%) as compared to other substances. Due to their direct action, AT1-receptor-blockers might also be of high effectiveness for the treatment of severe heart failure. A combination of the ACE-inhibitor-mediated activation of the kinin-system with the more specific blockade of AT1-receptors by AT1-receptor antagonists might be of benefit and is currently under investigation. Finally, it has been discussed that the increased AT II concentration in case of AT1-receptor-blockade activates AT2-receptor-mediated mechanisms thus leading to an additive vasoprotective effect.

Angiotensin Receptor Antagonists↗

PubMed1996

Block of P/Q-type calcium channels by therapeutic concentrations of aminoglycoside antibiotics.

Aminoglycoside antibiotics can cause neuromuscular block by inhibiting Ca2+ influx into motor nerve terminals. P/Q-type Ca2+ channels, which are formed by alpha 1A subunits, are mainly responsible for depolarization-dependent presynaptic Ca2+ entry in motor neurons. We therefore investigated the possibility that aminoglycosides function as P/Q-type channel blockers. They inhibited [125I]-omega-CTx-MVIIC binding to P/Q-type channels in guinea pig cerebellum membranes with nanomolar IC50 values (e.g., 8 nM for neomycin). Divalent cations decreased the apparent affinity of neomycin. Barium inward currents through alpha 1A subunits expressed in Xenopus oocytes were partially blocked by therapeutic concentrations of aminoglycosides. This explains that therapeutically relevant concentrations of these drugs decrease the reserve of neuromuscular transmission, which can lead to neuromuscular block. We conclude that micromolar concentrations of aminoglycosides block not only N-type but also P/Q-type channels in mammalian neurons.

Animals↗

PubMed1996

[CT-assisted definition of puncture site and penetration angle for percutaneous lumbar diskectomy].

In 20 consecutive patients submitted to CT evaluation of a suspected disk protrusion at level L4-5, CT measurements to define entry point and penetration angle for percutaneous diskectomy were performed. It was shown that in order to reach the disk center, the entry point had to be more lateral than recommended by most authors. Body height, weight and body surface area were not significantly correlated to entry point position or penetration angle. In particular, the extension of the intervertebral facet joint determined the route of the probe to the disk center. Therefore, CT-assisted planning of the instrument route prior to percutaneous lumbar diskectomy is helpful in defining the proper entry point and penetration angle for safe and effective instrument positioning.

Adult↗

PubMed1996

Natriuretic peptides and cyclic guanosine 3',5'-monophosphate in asymptomatic and symptomatic left ventricular dysfunction.

BACKGROUND: Screening for patients with asymptomatic left ventricular dysfunction is of considerable importance because they may benefit from early treatment with angiotensin converting enzyme inhibitors. It has been suggested that atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and cyclic guanosine 3',5'-monophosphate (cGMP) might be useful markers for screening. OBJECTIVE: To compare directly the power of the three immunoreactive forms of ANP (CT-ANP, beta-ANP, NT-ANP) and BNP and cGMP to detect asymptomatic left ventricular dysfunction. METHODS AND RESULTS: Radionuclide ventriculography was used to study left ventricular ejection fraction in 37 patients with asymptomatic left ventricular dysfunction, 32 patients with mild to moderate congestive heart failure, and 38 controls. CT-ANP, NT-ANP, beta-ANP, BNP, and cGMP were measured at rest and 3 minutes after exercise. Plasma BNP was the most sensitive marker for patients with asymptomatic left ventricular dysfunction but it reached only a sensitivity of 58% and a specificity of 76% at rest and a sensitivity of 65% and a specificity of 84% after exercise. Combined measurements of all natriuretic peptides and cGMP did not improve the power to detect asymptomatic left ventricular function above that of a single BNP measurement. CONCLUSIONS: Although natriuretic peptides and cGMP measured at rest and three minutes after ergometry may be useful for monitoring left ventricular dysfunction they are unlikely to be suitable for more general routine screening for completely asymptomatic left ventricular dysfunction.

Adult↗

PubMed1996

[Inhibition of the renin-angiotensin system: ACE inhibitors and angiotensin II receptor blockers].

The renin-angiotensin system (RAS) plays an important role in blood pressure regulation and fluid homeostasis in people with and without hypertension. The ACE-inhibitors were the first of the RAS blocking agents to have a wide clinical acceptance. Several trials demonstrated their usefulness in the treatment of essential hypertension, congestive heart failure, post myocardial infarction and diabetic renal disease. The recent development of selective angiotensin II type 1 receptor II blockers offers the compelling concept of interfering on the receptor level without disruption of the prostaglandin and bradykinin biosystems. Losartan, the prototype of orally active angiotensin II type 1 receptor antagonists, has been shown to be safe and effective in control of elevated blood pressure and improvement of the abnormal hemodynamics in the patient with congestive heart failure. These early encouraging results have to be confirmed by studies translating the circulatory benefits into augmented end-organ protection and prolongation of life.

Angiotensin Receptor Antagonists↗

PubMed1995

A deletion polymorphism in the angiotensin converting enzyme gene is not associated with coronary heart disease in an Austrian population.

This study examined a possible relationship between genetic variation in the gene coding for the angiotensin converting enzyme (ACE) and increased risk for coronary heart disease (CHD) in an Austrian population. Polymerase chain reaction (PCR) was used to determine the genotypes for an insertion/deletion polymorphism in intron 16 of the ACE gene in 315 patients with CHD and in 149 normal controls. In the control group, the relative allele frequencies of the polymorphism were similar to those of previously published European studies. The genotype distribution among our patients was not significantly different from that among controls. We were not able to show a significant association of the DD genotype with coronary heart disease in subgroups containing patients considered at low coronary risk. There was no association of lipid parameters and ACE genotype. From these data we conclude that, in the Austrian population, the insertion/deletion polymorphism in the ACE gene cannot be used as a marker for coronary risk assessment.

Adult↗