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A Albrecht

Publications and source records attributed to A Albrecht.

At least 19 recordsLinked to original sources
PubMed2001

Opportunities for future supernova studies of cosmic acceleration.

We investigate the potential of a future supernova data set, as might be obtained by the proposed SNAP satellite, to discriminate among different "dark energy" theories that describe an accelerating Universe. We find that many such models can be distinguished with a fit to the effective pressure-to-density ratio w of this energy. More models can be distinguished when the effective slope dw/dz of a changing w is also fit, but only if our knowledge of the current mass density Omega(m) is improved. We investigate the use of "fitting functions" to interpret luminosity distance data from supernova searches.

Astronomy↗
PubMed2001

Logarithmic simulated annealing for X-ray diagnosis.

We present a new stochastic learning algorithm and first results of computational experiments on fragments of liver CT images. The algorithm is designed to compute a depth-three threshold circuit, where the first layer is calculated by an extension of the Perceptron algorithm by a special type of simulated annealing. The fragments of CT images are of size 119x119 with eight bit grey levels. From 348 positive (focal liver tumours) and 348 negative examples a number of hypotheses of the type w(1)x(1)+. . .;+w(n)x(n)>/=theta were calculated for n=14161. The threshold functions at levels two and three were determined by computational experiments. The circuit was tested on various sets of 50+50 additional positive and negative examples. For depth-three circuits, we obtained a correct classification of about 97%. The input to the algorithm is derived from the DICOM standard representation of CT images. The simulated annealing procedure employs a logarithmic cooling schedule c(k)=Gamma/ln(k+2), where Gamma is a parameter that depends on the underlying configuration space. In our experiments, the parameter Gamma is chosen according to estimations of the maximum escape depth from local minima of the associated energy landscape.

Algorithms↗
PubMed2001

The negative regulator Opi1 of phospholipid biosynthesis in yeast contacts the pleiotropic repressor Sin3 and the transcriptional activator Ino2.

Structural genes of phospholipid biosynthesis in the yeast Saccharomyces cerevisiae are transcriptionally co-regulated by ICRE (inositol/choline-responsive element) promoter motifs. Gene activation by an ICRE is mediated by binding of the Ino2/Ino4 transcription factor, whereas repression in the presence of high concentrations of inositol and choline (IC) requires an intact Opi1 repressor. However, the mechanism of specific repression and the functional interplay among these regulators remained unclear from previous work. Using in vivo as well as in vitro interaction assays, we show binding of the pleiotropic repressor Sin3 to the pathway-specific regulator Opi1. The paired amphipathic helix 1 (PAH1) within Sin3 and OSID (Opi1-Sin3 interaction domain) in the N-terminus of Opi1 were mapped as contact sites. The regulatory significance of the Opi1-Sin3 interaction was shown by the obvious deregulation of an ICRE-dependent reporter gene in a sin3 mutant. Opi1 also interacts with a newly identified functional domain of the transcriptional activator Ino2 (RID, repressor interaction domain). These results define the molecular composition of the transcription complex mediating control of ICRE-dependent genes and allow a hypothesis on the flow of regulatory information in response to phospholipid precursors.

Amino Acid Sequence↗
PubMed2001

Flexible versus rigid endoscopes for outpatient hysteroscopy: a prospective randomized clinical trial.

To evaluate patient acceptance, optical properties and the clinical feasibility of flexible compared with rigid hysteroscopes, 142 patients undergoing outpatient hysteroscopy were included in a prospective, randomized clinical trial. The flexible hysteroscope was used in 70 patients, and the rigid instrument in 72. At different stages of the hysteroscopy the level of pain experienced by the women was assessed using a 10 cm visual analogue scale. Optical properties characterized by the parameters intrauterine visibility, hysteroscopic view and diagnostic accuracy were ranked by the surgeons using a 5-point scale (1 = excellent to 5 = insufficient), and duration of the hysteroscopy was measured. Hysteroscopy was successful in 87.5 and 100% of patients in the flexible and rigid groups respectively. With the use of rigid telescopes, discomfort at introduction and during the hysteroscopy was significantly greater (median 1.7 versus 0.7, P = 0.003; 3.1 versus 1.2, P < 0.001 respectively), but optical properties were judged to be far superior (P < 0.001 for all three comparisons) and procedure time was significantly shorter (median 70 versus 120 s, P = 0.003). In conclusion, outpatient hysteroscopy seems to be less painful when using flexible telescopes. However, rigid hysteroscopes provide superior optical qualities and permit a more rapid performance with higher success rates at much lower cost.

Adult↗
PubMed2000

[Technique and results of laparoscopic conservative organ-preserving myoma enucleation].

Myoma is one of the most common benign diseases of the female genital tract. The surgical management of this entity has been altered over the last years from complete hysterectomy to conservative enucleation of the myomas. We retrospectively compared our data concerning laparoscopic or open myomectomies. Over a period of 2 years, we operated 207 myomas in 102 patients. Of this collective, 69 (67.6%) were operated on laparoscopically and 33 (32.4%) via an open approach. In both groups, the median number of myomas was 2 (1-7). The mean diameter of the largest myoma was 5.1 +/- 2.4 cm (laparoscopy) and 6.2 +/- 2.6 cm (laparotomy), respectively. The additive diameter of myomas was 7.7 +/- 5.1 cm (laparoscopy) and 9.8 +/- 4.1 cm (laparotomy), respectively. There was no relevant difference between the groups in terms of operating time and blood loss. Four (3.9%) laparoscopies had to be converted to an open approach. In three cases (2.9%) a laparoscopically assisted enucleation had to be performed, requiring a mini-laparotomy 4 to 5 cm in length. We encountered no severe complications. Given appropriate indication, laparoscopic myomectomy is an easy-to-perform and minimally invasive technique with a low complication rate.

Adult↗
PubMed2000

Phenomenology of a realistic accelerating universe using only planck-scale physics

Modern data are showing increasing evidence that the Universe is accelerating. So far, all attempts to account for the acceleration have required some fundamental dimensionless quantities to be extremely small. We show how a class of scalar field models (which may emerge naturally from superstring theory) can account for acceleration which starts in the present epoch with all the potential parameters O(1) in Planck units.

Journal Article↗
PubMed1999

Neurocognitive functioning and improvement in quality of life following participation in cardiac rehabilitation.

We investigated the relationship between neurocognitive functioning and quality of life/self-perceived health status (QOL) among cardiac rehabilitation (CR) patients to determine whether level of neurocognitive functioning is related to baseline QOL and improvement following CR. CR patients (n = 35) were given a neurocognitive screening before participation in CR, and also completed a behavioral inventory (SF-36) before and after CR to measure QOL associated with medical illness. At baseline, CR patients obtained relatively low SF-36 scores compared with published norms, and as reported previously, demonstrated inferior neurocognitive performance compared with healthy controls. Furthermore, neurocognitive performance was strongly positively correlated to SF-36 scores. Significant improvements were evident on many of the SF-36 subscales following rehabilitation. These improvements were relatively greater among SF-36 indexes of physical health status compared with SF-36 indexes of mental health status. Baseline neurocognitive performance also correlated strongly to the degree of improvement in SF-36 scores following rehabilitation. These findings indicate a strong relationship between baseline neurocognitive functioning and QOL before CR, and the degree to which QOL improves following this intervention.

Aged↗
PubMed1999

[Ambulatory hysteroscopy in evaluation of postmenopausal bleeding].

INTRODUCTION: Diagnostic hysteroscopy is the most precise procedure to evaluate diseases involving the uterine cavity. There is, however, only limited data concerning the use of hysteroscopy carried out as an outpatient procedure in patients with postmenopausal bleeding. MATERIALS AND METHODS: In this study we report on 360 postmenopausal patients with erratic bleeding, who were referred to our outpatient hysteroscopy clinic. 185 women had frank postmenopausal bleeding (PMB) and another 175 had abnormal uterine bleeding while taking hormone replacement therapy (AUB). The mean age was 57.9 years (range: 42-86). All hysteroscopies were performed using a standard 5-mm hysteroscope with a 30 degrees fore-oblique lens; the uterine cavity was generally distended with normal saline. RESULTS: Outpatient hysteroscopy was performed successfully in 339 patients (94.2%). In 166 cases (46.1%) cervical dilatation was necessary, and 138 required (38.3%) intracervical anaesthesia. Intrauterine pathology was diagnosed in 49.6% of cases, with endometrial polyps (20.9%) and fibroids (15.9%) being the most common abnormalities. While there was no difference in the incidence of intrauterine lesions between patients with AUB and those with PMB, endometrial carcinoma was more common in the latter group (PMB: n = 11 vs. AUB: n = 1; p < 0.002). CONCLUSION: Due to its high accuracy and patient acceptance, outpatient diagnostic hysteroscopy should become a first line investigation in postmenopausal patients with bleeding disorders.

Adenocarcinoma↗
PubMed1999

A double-blind, prospective, randomized, multicenter group comparison study of iopromide 240 vs iohexol 240 in myelography.

The aim of this study was to evaluate the safety and efficacy of iopromide 240 mgI/ml in comparison with iohexol 240 mgI/ml in myelography. A total of 421 patients in seven centers and four countries received an average of 11.9 ml of either iopromide 240 (278 patients) or iohexol 240 (143 patients) for X-ray and/or CT myelography in a randomized (2:1), prospective, double-blind study. All patients were followed up 3-4 h after the procedure, and 327 patients remained hospitalized for 24 h. In 82 patients an EEG was recorded prior to as well as 3-4 h and 24 h after myelography. Physical examinations, including measurement of vital signs, were performed in all patients at these time points. The results were subject to statistical analysis with the primary variable being the incidence of adverse events. Both contrast media (CM) were equally effective in terms of opacification. The rating for opacity was "good" or "excellent" in 88 % for both CM. Four patients (iopromide group: n = 3; iohexol group: n = 1) had transient EEG changes but did not show clinical symptomatology. The overall rate of patients experiencing any adverse event (AE) was 16.9 % for iopromide 240 and 14.0 % for iohexol 240. Equivalence testing was inconclusive; however, the results indicated equivalence. The rate for AEs considered as study-drug related was slightly lower with iopromide 240 than with iohexol 240 (7.2 vs 7.7 %, respectively). Neither unknown nor unexpected AEs known for myelographic X-ray CM nor serious adverse events were observed. Iopromide 240 and iohexol 240 are equally safe and effective and can be recommended for myelography.

Adolescent↗
PubMed1999

Quality of life and anxiety in a phase II cardiac rehabilitation program.

PURPOSE: Cardiac rehabilitation programs increasingly attempt to improve both quantity and quality of life (QOL). Documenting QOL changes requires appropriate instruments, and interpreting QOL data requires an understanding of the factors that influence such reports. METHODS: To address both issues, we assessed QOL among 77 patients before and after participation in a 12-wk phase II cardiac rehabilitation program. Individual psychological differences in trait anxiety and defensiveness were also assessed. The sample was 76.6% male, 70.1% married, and had a mean age of 58.8 yr. RESULTS: The QOL scales detected changes which occurred over the 12-wk testing period. QOL reports were strongly and differentially influenced by individual differences in trait anxiety, such that patients reporting high trait anxiety displayed poorer QOL than those low in trait anxiety. More specifically, trait anxiety influenced affect reports most strongly, functional aspects moderately, and physical aspects of QOL reports the least. CONCLUSIONS: Defensiveness was unrelated to QOL reports. The 17% of participants who voluntarily left the rehabilitation program prematurely were characterized as younger, having better self-perceived health, having a less severe cardiac history, and being high in both trait anxiety and defensiveness. Study benefits and limitations are discussed.

Analysis of Variance↗
PubMed1999

Results of the surgical treatment of chronic atrial fibrillation.

OBJECTIVE: Report clinical experience in surgical treatment of atrial fibrillation (AF) by Cox-maze procedure. METHODS: 61 patients underwent surgical treatment for AF. Two had primary AF and 59 AF secondary to heart disease (2 atrial septal defects, 57 mitral). Ages ranged from 20 to 74 years (mean = 49). There were 44 females (72%). The surgical technique employed was Cox 3 without cryoablation. The patients were follow-up in specific at patient clinics and underwent periodical ECG, exercise tests, echocardiogram and Holter monitoring. RESULTS: In-hospital mortality was 4.9% and late mortality 1.6%. A temporary pacemaker was used in 28 (46%) and a definitive in 7 patients (11.4%). On hospital discharge, AF remained in 17%; 63.9% had sinus rhythm, 6.9% atrial rhythm, 1.7% junctional rhythm, and 10.3% had pacemaker rhythm. In the last evaluation, AF was present in 19.5%; (70.5% sinus rhythm, 4% atrial rhythm, 2% atrial tachycardia, and 4% pacemaker rhythm). There was no report of thromboembolic episodes. Chronotropic response was considered adequate in 19%, intermediate in 29%, and inadequate in 42%. In Holter monitoring, the mean heart rate was 82 +/- 8 bpm, with a minimum of 57 +/- 7 bpm and maximum of 126 +/- 23 bpm, with supraventricular extrasystoles in 2.3 +/- 5.5% of the total heartbeats and ventricular extrasystoles in 0.8 +/- 0.5%. In the echocardiogram, the A wave was present in the left atrium in 87.5%. CONCLUSION: Maze procedure is effective and has acceptable surgical risk. Atrial or sinus rhythms remain stable with a small but remarkable frequency of atrial and ventricular arrhythmias. Left atrial contraction is present, although attenuated, as well as the chronotropic response to exercise.

Adult↗
PubMed1999

[Measuring the spread of airborne microorganisms in the area of composting sites].

Emission concentrations of culturable microorganisms were determined in the vicinity of three open or partly encapsulated composting facilities. Sampling was performed during so-called worst case situations which should promote aerial transport of emissions. Suitability of thermophilic organisms to detect an emitting influence of the plant was confirmed. Generally, concentrations decreased significantly with increasing distances from the plant at all three locations. At one plant 10(6) CFU m-3 thermophilic actinomycetes were found in a distance of 200 m. Partly increased concentrations could be determined even in distances above 500 m. Concentrations could vary within one hour to more than ten times.

Actinomycetales↗
PubMed1998

[First annual report of practitioners of interventional cardiology in private practice in Germany. Results of procedures of left heart catheterization and coronary interventions in the year 1996].

The German Society for Cardiac Angiography and Interventions in Private Practice has started a registry of cardiac procedures since 1996 in order to establish a standard for performance. Although quality management for the cath lab makes sense and is also legally required, there is no generally recommended infrastructure for quality assurance existing in Germany at this time. Therefore, the German Society of Cardiologists in Private Practice (BNK) initiated a project in 1994 to develop a computer program for paperless documentation of diagnostic cardiac catheterizations and coronary interventions (PTCA) using a minimal data set. In 1996, 8 private associated groups participated in this project. The (anonymous) analysis of 10,316 diagnostic cardiac catheterizations and 2597 PTCA yielded the following results: In 95% of the patients, diagnostic cardiac catheterization was performed using the femoral and in 5% the brachial/radial approach. The mean volume of administered contrast medium was 164 +/- 138 ml/patient. The mean LV-EF was greater than 50% in 58.4% of the patients and between 30% and 50% in 10.1%. Coronary artery disease was diagnosed in 69.6% of the patients and valvular/congenital heart disease in 8.5%. In 18.4% of the patients undergoing diagnostic cardiac catheterizations no significant heart disease was identified. Mortality in the cath lab as well as the rate of cerebral insults was 0.05%. In 22.9% and 19% of the patients PTCA and cardiac surgery respectively was recommended. In patients undergoing PTCA, stable angina was present in 74.4% and unstable angina in 13.1%. Of the total number of PTCA procedures, 5.8% were performed in the setting of acute myocardial infarction. The PTCA lesion success rate was 96%, the mean diameter stenosis was 81% pre and 6% post-intervention. The mortality rate at 1 month post-PTCA was 0.4%, and myocardial infarction 1.0%. An acute occlusion occurred in 1.3% of the PTCA patients; 0.6% had to be transferred for emergency bypass surgery. None of the cath labs had on-site surgery. In comparison to other registries, our data show some similarities but also some different trends. Thus, our newly developed software proved to be reliable, fast and easy to use. Participating centers receive immediate feedback regarding their position within the whole group.

Angiocardiography↗
PubMed1998

Atraumatic cervical passage at outpatient hysteroscopy.

OBJECTIVE: To evaluate the efficacy of topical anesthesia routinely administered to reduce discomfort and the need for additional local anesthesia during outpatient hysteroscopy. DESIGN: Comparative observational study. SETTING: Outpatient hysteroscopy clinic in a University hospital. PATIENT(S): Three hundred patients undergoing outpatient hysteroscopy. INTERVENTION(S): Application of lidocaine spray both to the surface of the cervix and into the cervical canal before performing hysteroscopy. MAIN OUTCOME MEASURE(S): The discomfort during passage of the hysteroscope through the cervical canal, the need for additional local anesthesia, and the failure rate of outpatient hysteroscopy. RESULT(S): One hundred fifty consecutive patients receiving lidocaine spray before the hysteroscopy were compared to a control group of another 150 consecutive patients who underwent the examination without pretreatment. Women treated with spray experienced significantly less pain at insertion of the hysteroscope. Furthermore, the spray significantly reduced both the need for additional anesthesia and the rate of failed hysteroscopies due to intolerable pain. CONCLUSION(S): Topical anesthesia with lidocaine spray is a simple method to alleviate patients' discomfort during cervical passage. It is effective in reducing the need for local anesthesia and should reduce the rate of failed outpatient hysteroscopies.

Adolescent↗
PubMed1998

Exercise, smoking cessation, and short-term changes in serum lipids in women: a preliminary investigation.

PURPOSE: This study investigated the combined effects of exercise and smoking cessation on serum lipids. METHODS: Eighteen female smokers quit smoking using standard behavioral methods combined with exercise (N = 9) or with a nonexercise contact time control (N = 9). The smoking cessation program for both groups consisted of 12 weekly 1-h behavioral modification sessions held over 12 wk. Exercise training consisted of three supervised 45-min sessions per week for 12 wk. Contact control consisted of three health education lectures/discussions per week for 12 wk. Fitness (estimated VO2 peak), dietary variables, and fasting serum lipids and lipoproteins were assessed before and at the end of treatment. VO2 peak increased in the exercise subjects compared with the controls. RESULTS: Total caloric intake as well as total fat and carbohydrate increased significantly after smoking cessation in the controls, but there were no dietary changes in the exercise group. high density lipoprotein (HDL)-C2 increased (7.6 mg x dL(-1), P < 0.01) in the exercise group, whereas the increases in HDL and its subfractions did not attain statistical significance in the contact control group. Total cholesterol, low density lipoprotein (LDL)-C, and triglycerides did not change in either group. CONCLUSIONS: We conclude that exercise training magnifies the increase in HDL-C that usually occurs with smoking cessation.

Adult↗
PubMed1997

Effect of hormone replacement therapy on growth hormone stimulation in women with premature ovarian failure.

OBJECTIVE: To assess the effect of oral hormone replacement therapy (HRT) on body weight, insulin-like growth factor I (IGF-I), and GH response to exogenous GHRH [corrected] in women with premature ovarian failure (POF) [corrected]. DESIGN: Controlled clinical study. SETTING: Outpatients studied in the department of endocrinology of the University Hospital in Vienna. PATIENT(S): Twenty-four women with POF (study group) and 24 volunteers with normal ovarian cycles (control group). INTERVENTION(S): Pituitary GHRH [corrected] stimulation was performed in all women at study entry and in patients with POF after 1, 6, and 12 months of standard oral HRT. Blood samples were collected from 15 minutes before to 120 minutes after GHRH administration [corrected]. Body weight also was evaluated. RESULT(S): No differences in baseline and stimulated serum GH were found either between POF women and controls or in POF women during HRT. Women with POF without HRT had significantly higher IGF-I levels; a reduction in circulating IGF-I levels occurred during HRT. Body weight remained stable. CONCLUSION(S): Our results show the following: [1] Women with POF have similar Gh secretion patterns as healthy age-matched women; [2] physiologic HRT has no impact on GHRH-induced [corrected] GH stimulation; and [3] HRT has no impact on body weight in women with POF.

Adult↗