Biomedical subjects
Publications and source records attributed to M Popescu.
It presents the "thickenings" of the extraocular muscles that can cause exophthalmos. It makes the difference between myositis limited to the orbit and the systemic myopathies and endocrine myopathies.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Image analysis research aimed at analyzing images of banded, human chromosomes is described. An experimental automated karyotyping system (AKS) has been assembled. The goal of the system is to label the chromosomes from a metaphase image with minimal human intervention. The AKS is unique in that it is designed to automatically process cells containing overlapping chromosomes. It also has four novel algorithmic features: the use of cross section sequence graphs, an over-segmentation-based segmentation strategy, the use of the 'pale path' concept for banded chromosomes and the application of mathematical programming for cell-level chromosome classification in cells with overlapping chromosomes. System performance was analyzed using a variety of metaphase images exhibiting various levels of overlapping chromosomes.
Centralvenous obstruction is a rare however typical lesion with patients on chronic hemodialysis. A still functional arteriovenous shunt in its run-in can cause serious disorder, especially painful congestion and an insufficient dialysis. Should the shunt be maintained, a run-off reconstruction is required. 13 patients were treated with a centralvenous obstruction combined with a complication of the shunt. In 8 patients the intervention was either impossible from the beginning or finally proved to be not successful after repeated recanalisations. 6 out of these patients underwent a transsternal reconstruction of their bypass (a total of 7 interventions). 2 patients died perioperatively, 2 patients died 1 year, respectively 1 1/2 years later with a still intact reconstruction, 2 patients are still alive. Their reconstruction has been working for two, respectively three years. The bypass material was large-calibrated e-PTFE with external support. Compared to conventional indications the catheter techniques proved to be less effective in the treatment of central venous obstruction. One year after the first intervention only three out of seven shunts could still be used for the dialysis. The longest symptom-free period was 12 months. The operative reconstruction is indeed very effective but it implies considerable risks and effort. This method cannot be recommended to patients on chronic dialysis who are in a poor condition.
This study proposes a wavelet transform based technique to assess the beat-to-beat variation of the QRS signal in post-myocardial infarction patients with sustained monomorphic ventricular tachycardia. Recent electrophysiological investigations suggested that the diminished synchrony between the normal myocardium and the scarred arrhythmogenic tissue bordering a myocardial infarction area gives rise to beat-variable ECG signal components. Using a mathematical model of small variations in a largely repetitive waveform, we show that the inherent alignment errors (trigger jitter) of the high-resolution ECG (HRECG) can artificially increase the value of the time-domain beat-to-beat variance, making it less valuable as a marker of beat-variable signal components. To overcome this drawback, we propose the wavelet based approach which discriminates between the different factors responsible for the beat variability (the alignment error and the beat-variable signal components). The Morlet wavelet transform is performed on HRECG signals from normal individuals (control group) and postmyocardial infarction patients with documented ventricular tachycardia. Electrical variability is quantitatively assessed via the beat-to-beat wavelet variance measurements. A marker of arrhythmogenic induced variance which achieves a good performance in discrimination of ventricular tachycardia patients from normal subjects was found between 200 Hz and 300 Hz. This finding is in agreement with the proposed mathematical model which states that the useful part of the time-frequency map is shifted upward in a precise mathematical way, as the variance induced by the beat-variable arrhythmogenic signals depend on the frequency characteristics of the first derivative of these signals. We conclude that the dynamics of the arrhythmogenic substrate as revealed by the beat-to-beat wavelet variance can be a new estimator of ventricular tachycardia risk.
The objective of this analysis was to examine the effect of low birth weight and prematurity on bronchial air-flow, bronchial reactivity, airway symptoms and asthma diagnosis at school age. A cross-sectional epidemiological study was performed in three small towns in the eastern part of Germany on 2470 school children aged 5-14 (89.1% of eligible children). A 78 item questionnaire to determine risk factors at birth and in early childhood was employed. 7.8% of the children were born before completing 38 gestational weeks; 6.6% had a birth weight less than 2500 g. Pulmonary function analysis were done by a mobile plethysmography at the school. There were only weak restrictions in lung volume in term low birth weight (LBW) children (100 ml lower TLC, p = 0.107), and flow (257 ml lower PEFR, p = 0.108), were low. However, bronchial hyper-responsiveness indicated by 292 ml lower FEV1.0 after cold air bronchial provocation, was significantly increased compared to term normal birth weight children (p < 0.001). The effect of LBW was less in older children, only slightly stronger in girls and increased in children mechanically ventilated during the postnatal period. Correspondingly, there was a higher prevalence of diagnosed asthma in term LBW children (OR 1.6, 95%-confidence interval 1.0-2.6), however these were without an increased risk for any allergic sensitization. LBW, therefore, seems to be a risk factor for smaller lungs and hyperreactive airways primarily in term born children, whereas in preterm children the immature bronchial system seems to be recover by school age.
There are shown two cases of glial hamartoma of the optic nerve head. In both cases the retinal vessels are tortuous around the optic nerve disc, and the choroid shows a brown colour, like a choroidal naevus. Histologically this kind of tumors of the optic nerve head are astrocytomas and they are met specially under the age of twenty. The glial hamartoma of the optic nerve head is a rare disease.
A variation of the Shinnar-Le Roux (SLR) method of pulse envelope design that allows for control of the phase of the frequency response profile has been developed. The method makes use of the fact that a knowledge of one of the SLR polynomials in combination with a root inversion pattern for the other polynomial is sufficient to fully define the second polynomial. Optimization of the first polynomial, when cast in this form, remains nonlinear. However, it was demonstrated that the relationship between the SLR polynomials and the frequency response profile may be used to generate an initial guess for the SLR polynomials that is sufficiently accurate to allow for the application of linear optimization techniques in most cases. In practice several pulse envelopes having different root inversion patterns are investigated for each target profile. The resulting collection of pulses allows the user to trade off pulse power for profile accuracy. The proposed technique was used to design a large number of amplitude modulated excitation pulses having trapezoidal magnitude and linear phase frequency response profiles. A few examples of the resulting pulses and their response profiles are presented.
The unstable activation wavefront from the tissue responsible for the production of ventricular tachycardia (VT) gives rise to beat-variable signals components that are eluded during the averaging step of high resolution ECG (HRECG). We used a mathematical model of small variations in a largely repetitive waveform to evaluate the beat-to-beat variance of the HRECG signal. The ability of the Morlet Wavelet Transform to discriminate the different factors responsible for the beat-variability (the alignment error and the beat-variable signal component) has been assessed on simulated signals. The performance evaluation on real ECG signals from normal subjects and patients with a documented history of ventricular tachycardia showed that the dynamics of the arrhythmogenic substrate as revealed by wavelet transform offers a significant improvement in ventricular tachycardia risk assessment.
The internal burden of arsenic among 5- to 14-year-old eastern German children in the heavily polluted areas of Hettstedt, a region of smelting and copper mining, and Bitterfeld, a center of chemical production and coal mining, was compared with that in a control area (Zerbst) by means of urinary arsenic concentrations in 1992-94. The unadjusted geometric mean among the 950 children was significantly higher in Hettstedt (5.1 micrograms/l; 95% C.I. 4.8-5.5) but not in Bitterfeld (4.3 micrograms/l; 95% C.I. 3.7-4.9) compared with the control area (4.0 micrograms/l; 95% C.I. 3.5-4.5). This difference persisted after adjustment for relevant confounders. Despite these regional differences, recent fish consumption was as strongly associated with urinary arsenic levels (42% increase, 95% C.I. 18-71%). Additionally, although the geometric mean among the children in Hettstedt (4.8 micrograms As/g creatinine; 95% C.I. 4.5-5.1) was higher than that found in an environmental survey of eastern German children (3.60 micrograms As/g creatinine; 95% C.I. 3.06-4.24), it was similar to that found among western German children (4.59 micrograms As/g creatinine; 95% C.I. 4.20-5.02). This suggests that the arsenic contamination in Hettstedt is not substantially increasing the internal burden of arsenic among children above that found in other German children.
OBJECTIVE: To investigate the ability of elevated serum neopterin levels to predict independently mortality, progression to acquired immunodeficiency syndrome, and development of neurological disease. DESIGN: Cross-sectional and longitudinal study of gay and/or bisexual men and parenteral drug users. SETTING AND PATIENTS: Patients included human immunodeficiency virus (HIV)-negative and -positive gay and/or bisexual men and parenteral drug-using men and women who volunteered for an outpatient study of the natural history of HIV infection. RESULTS: Serum neopterin levels were significantly elevated in HIV-positive patients (mean, 18.0 nmol/L; SD, 19.2 nmol/L), compared with those in HIV-negative patients (mean, 7.5 nmol/L; SD, 5.5 nmol/L) (P < .001). No differences in the serum neopterin levels could be detected between gay men and parenteral drug users. In HIV-positive patients, women had a higher serum neopterin level than did men (P = .03). The elevated serum neopterin levels were associated with an advanced clinical stage of HIV infection. After adjusting for the CD4 lymphocyte count and other potential confounders, the serum neopterin level was a significant independent predictor of mortality. The elevated serum neopterin levels did not predict progression to acquired immunodeficiency syndrome or development of clinically significant neurological disease. CONCLUSION: An elevated serum neopterin level predicts mortality, but it does not predict progression to acquired immunodeficiency syndrome or development of neurological disease among HIV-infected individuals.
Explore the source record for details and available documents.
We describe pneumomediastinum in a primigravida with delay in the second stage of labor. The pathophysiology, clinical presentation, and management are reviewed.
In a retrospective study of the records of 64 patients with AIDS and cytomegalovirus (CMV) retinitis, 47 patients were evaluated regarding the effectiveness of initial virustatic therapy, and 41 patients regarding the anatomical and functional long-term development (maintenance therapy, rate and intervals of recurrences, complications, adverse drug reactions, time of survival, and visual outcome). The average survival time of 45 treated patients was 226 days (31-717 days). More than 90% responded to initial therapy with ganciclovir or foscarnet. Forty-four percent remained free of recurrences until they died (for up to 15 months); 56% had 1 to 4 recurrences, altogether 35 episodes, of which 14 occurred after withdrawal of therapy. Recurrences were treated with high-dose reinduction therapy with good or partial response in more than 80% of cases. Nine patients showed "smouldering retinitis" at a late stage. Two out of 45 patients became blind shortly after diagnosis despite therapy; both showed a course mimicking acute retinal necrosis syndrome with histologically proven CMV disease. None of the 43 patients on maintenance therapy for up to 2 years became blind in both eyes. Only 2 out of 43 patients had a poor visual outcome < 40/100 in the better eye at a late disease stage. Of 60 affected eyes, 11 showed retinal detachment, 14 eyes developed optic atrophy and 12 eyes became blind. Our retrospective study shows that consistent maintenance therapy of patients with CMV retinitis prevents severe deterioration of visual acuity in most cases even in long disease courses and thus maintains quality of life.
One hundred ninety four children, 11 +/- 1.5 years of age and 166 elderly men and women, 77 +/- 8 years of age were studied over one or (in the case of some of the elderly subjects) over several (up to 4) 24-hours spans. All subjects were diurnally active and rested at night and followed their regular three meal pattern. The subjects were studied in subgroups of 20-25 during all four seasons of the year. During each study, blood was collected at 4 hour intervals over one 24-hour span (6 samples). Circadian and circannual variations were found and described by cosinor analysis in the children as well as in the elderly subjects. The children with endemic goiter (134) as compared to those without endemic goiter (60) showed a slight circadian phase advance in plasma total and free T3, a lower circadian amplitude of total T4 concentrations and the absence of a detectable circadian rhythm in free T4. The children with goiter showed a phase delay in serum TBG. There was no difference between the children with and without goiter in the circadian MESOR of any thyroid parameter or of TSH. The children with endemic goiter in the region of Dimboviţa, Romania, are in clinical and biochemically euthyroid condition with some slight poral abnormalities of thyroid function. Seasonal variations in children and elderly patients showed the highest values of TSH during summer and fall, while the highest values in the plasma concentrations of thyroid hormones were found during the cold season of the years. Thyroglobulin in the children showed a circadian rhythm but no seasonal variation.
There are not yet unselected studies on psychopathological syndromes in the course of HIV-infection in German-speaking countries. In a group of 55 patients in different stages of the infection two psychiatric explorations were done within an interval of about one year. The findings were analysed by the Brief Psychiatric Rating Scale (BPRS). The degree of psychosocial functioning was estimated using the GAF-scale (axis 5 of DSM-III-R). The diagnosis of dementia was based on DSM-III-R-criteria. Most of the patients (72%) showed normal or only slightly remarkable psychopathologic findings at both times. A significant increase in psychopathologic conspicuousness in the course of the disease was only found for the subscore BPRS 2 ("anergia"). Dementia was seen in five patients (9%) and only in the stage of manifest immune deficiency syndrome (WR 6). All-together there was only a slight decrease of psychosocial functioning detectable (median on the GAF-scale 75), which only in dementia showed a significant reduction.