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Biomedical subjects

M Pavlova

Publications and source records attributed to M Pavlova.

18 recordsLinked to original sources
PubMed1999

Gamma-band MEG activity to coherent motion depends on task-driven attention.

We examined gamma-band magnetoencephalographic (MEG) activity in humans manipulating attention to visual stimuli by auditory distractors. After exposure to both visual and auditory noise (a baseline), subjects attended to the first of two stimuli (either regular motion of bars or a tone sequence) presented asynchronously, and responded to its offset. A spectral power analysis revealed an increased, relative to baseline, 40 Hz MEG response to attended coherent motion. The enhancement occurred within the initial 50-250 ms from motion onset over modality-specific (occipital) cortices. The increase was not observed when attention was captured by auditory distractors. Our findings suggest that 40 Hz activity in the human visual cortex is related to integration of featural information that is supported by attention.

Acoustic Stimulation↗
PubMed1999

Notochord-dependent expression of MFH1 and PAX1 cooperates to maintain the proliferation of sclerotome cells during the vertebral column development.

During axial skeleton development, the notochord is essential for the induction of the sclerotome and for the subsequent differentiation of cartilage forming the vertebral bodies and intervertebral discs. These functions are mainly mediated by the diffusible signaling molecule Sonic hedgehog. The products of the paired-box-containing Pax1 and the mesenchyme forkhead-1 (Mfh1) genes are expressed in the developing sclerotome and are essential for the normal development of the vertebral column. Here, we demonstrate that Mfh1 like Pax1 expression is dependent on Sonic hedgehog signals from the notochord, and Mfh1 and Pax1 act synergistically to generate the vertebral column. In Mfh1/Pax1 double mutants, dorsomedial structures of the vertebrae are missing, resulting in extreme spina bifida accompanied by subcutaneous myelomeningocoele, and the vertebral bodies and intervertebral discs are missing. The morphological defects in Mfh1/Pax1 double mutants strongly correlate with the reduction of the mitotic rate of sclerotome cells. Thus, both the Mfh1 and the Pax1 gene products cooperate to mediate Sonic hedgehog-dependent proliferation of sclerotome cells.

Animals↗
PubMed1998

Factors affecting the prognosis of Ebstein's anomaly during fetal life.

BACKGROUND: The echocardiographic criteria that have been used to evaluate severity of Ebstein's anomaly in utero are the same as those applied after birth. OBJECTIVE: The objective of this study was to establish prognostic criteria that take into account the peculiarities of the fetal hemodynamics. METHOD: The video recordings of eight fetuses with Ebstein's anomaly were retrospectively reviewed. RESULTS: The following indexes had no prognostic significance either on fetal or neonatal outcome: the ratio of functional tricuspid opening over the diameter of the annulus, the degree of displacement of the tricuspid valve opening, and the degree of tricuspid regurgitation. The index of severity (based on the surfaces of right atrium + atrialized right ventricle) and the cardiothoracic ratio had a significant impact only on neonatal survival. The smallest fossa ovalis were found in two fetuses who had hydrops. Fetuses who reached term without problems had higher left ventricular outputs. A positive linear correlation was found between the z score of the left ventricular output and the size of the fossa ovalis (r = 0.81, p < 0.05). CONCLUSION: The prognosis of Ebstein's anomaly during fetal life is not influenced by criteria described for postnatal life and may be related to factors that control the volume load of the left ventricle.

Ebstein Anomaly↗
PubMed1998

An assessment of the exposure of technicians working in a chemical laboratory for aromatic hydrocarbons at Neftochim, Burgas.

The average exposure to aromatic hydrocarbons per working shift of laboratory assistants at a chemical laboratory were measured. The laboratory is one of the service departments for four different production departments at Neftochim, Burgas--the largest oil refinery in Bulgaria. Long-term sampling of the air from different workplaces in the laboratory was performed by sampling charcoal sorbent tubes (type CT-CN-2), manufactured by Higitest (type NIOSH). The concentration of benzene, toluene, ethyl benzene, xylene and isopropyl benzene in the air at the laboratory was determined by gas chromatography using the Varian MEGA 1 with a flame ionisation detector and Inowax capillary column. The measured exposure levels of toxic substances in the aromatic hydrocarbons analysis laboratory were as follows: Benzene, 0.15-1.3 mg/m3, in single samples its concentration was 4.06-8.63 mg/m3; toluene, 0.15-0.46 mg/m3, in single samples its concentration was 5.5-15.62 mg/m3; ethyl benzene in most samples was 0.02 mg/ m3, in single samples its concentration was 20.68 mg/m3; xylene in most samples was 0.4 mg/m3, in single samples its concentration was 0.51-1.68 mg/m3; isopropyl benzene in most samples was 0.1 mg/m3, in single samples its concentration was 0.20-1.12 mg/m3. The results, obtained by measuring the average work-shift exposure of laboratory assistants to aromatic hydrocarbons in the air at the analytical laboratories, show that the measured concentrations are smaller than the respective threshold limit values. Bearing in mind, however, that some of these substances have an effect on the human organism, exposure to them is excessively hazardous for laboratory technicians.

Bulgaria↗
PubMed1997

Therapeutic efficacy of "Milgamma" in patients with painful diabetic neuropathy.

Forty-five diabetes patients with painful peripheral polyneuropathy were enrolled in a 3-month observational study comparing the therapeutic efficacy of Milgamma tablets (50 mg benfothiamine and 0.25 mg cyancobalamine) with parallel randomized treatment assignment with the conventional vitamin B complex treatment regimen Neurobex. Thirty patients in group one were randomized to receive two Milgamma tablets qid for three weeks followed by 1 Milgamma tablet tid for 9 weeks. In group two 15 patients received two Neurobex tablets tid for the entire 3-month study period. Therapeutic efficacy was assessed on the basis of within-patient differences in pain severity between Milgamma and Neurobex-treated patients and in vibration perception thresholds using the Rydel-Seiffer biothesiometer at baseline and at the end of the study. Statistically significant relief of both background and peak neuropathic pain was achieved in all of the Milgamma-treated patients and vibration perception thresholds dramatically improved with a median of 1.56 measured on the biothesiometer scale (t = 3.24, P < 0.01). The sensory symptoms improvement was insignificant in the Neurobex-treated patient group and the changes in the vibration perception thresholds failed to reach statistical significance. The therapeutic efficacy of Milgamma was greater in patients with early-stage diabetes as compared with those with advanced diabetic neuropathy. No adverse reactions were observed following the administration of the medication. Our results underscore the importance of Milgamma tablets as an indispensable element in the therapeutic regimen of patients with painful diabetic polyneuropathy.

Adult↗
PubMed1997

Percutaneous ethanol sclerotherapy of autonomous thyroid nodules: preliminary results.

Percutaneous ethanol sclerotherapy was applied to 20 patients (17 women and 3 men, aged 30 to 77 yrs) with autonomous thyroid nodules. The patients either were contraindicated because of hazardous concomitant diseases or refused surgical or 131I treatment. Ethanol (95 alc%) was injected in 4 to 6 sessions at a mean dose of 0.63 ml/cc nodular tissue. Physical examination, T3, T4 and TSH assays, thyroid scintigraphy, sonography, and fine needle aspiration biopsy were used to evaluate the treatment results within a 12-month follow-up. Two months after ethanol injection all patients showed an improvement; in six patients the symptoms recurred in the 6th month. Two of them underwent a second cycle of ethanol injection. 12 months later an euthyroid state was maintained in 16 (80%) patients, while 4 (20%) did not respond to the treatment. The treatment results were markedly determined by the nodule size as no effect was achieved in nodules larger than 15-20 ml in volume. This method appears to be an appropriate and harmless alternative to the surgical and 131I treatment of autonomous thyroid nodules less than 15-20 ml in volume, especially in patients with grave concomitant diseases.

Adult↗
PubMed1996

[Importance of intrauterine diagnosis of rudimentary autonomic circulation in an acardiac twin].

Foetal acardia is a major complication of twin pregnancies which endangers the life of the healthy twin. The authors report the case of a twin pregnancy with an acardiac twin followed up by repeated echocardiography from the 20th week of pregnancy until delivery at the 36th week. Despite the presence of a parasitic mass, the healthy twin showed no sign of heart failure. Attentive ultrasonography of this mass showed a certain degree of autonomic circulation ensured by a rudimentary cardiac pump. This case confirms the favorable effect of this finding on the healthy twin, moreover, it clarifies some haemodynamic features of the parasitic mass: to-and-fro circulation, characteristic of a cardiac pump without a valve, anastomoses and competitive flow between the two circulatory systems.

Abnormalities, Multiple↗
PubMed1995

Treatment of delayed sleep phase syndrome.

Delayed sleep phase syndrome (DSPS) is a common but little reported cause of severe insomnia. Affected individuals complain of difficulty falling asleep and difficulty awaking at socially acceptable hours. It results from a dysregulation of the circadian sleep-wake cycle. DSPS presents in clinically heterogenous ways as modulated by motivation, psychopathology, drug status, and treatment compliance factors. Patients respond variably to the range of possible treatments. Bright light treatment potentially corrects the circadian abnormality of DSPS. Other treatments reported to relieve some DSPS patients include schedule shifts, drugs, and vitamin and hormone treatments. The safety and efficacy of light treatment have not been conventionally defined, but available information suggests that it is ophthalmologically safe. At present, DSPS must be managed empirically by various methods.

Adolescent↗
PubMed1994

Structure of the Drosophila HeT-A transposon: a retrotransposon-like element forming telomeres.

Telomeres of Drosophila appear to be very different from those of other organisms. A transposable element, HeT-A, plays a major role in forming telomeres and may be the sole structural element, since telomerase-generated repeats are not found. HeT-A transposes only to chromosome ends. It appears to be a retrotransposon but has novel structural features, which may be related to its telomere functions. A consensus sequence from cloned HeT-A elements defines an element of approximately 6 kb. The coding region has retrotransposon-like overlapping open reading frames (ORFs) with a -1 frameshift in a sequence resembling the frameshift region of the mammalian HIV-1 retrovirus. Both the HeT-A ORFs contain motifs suggesting RNA binding. HeT-A-specific features include a long non-coding region, 3' of the ORFs, which makes up about half of the element. This region has a regular array of imperfect sequence repeats and ends with oligo(A), marking the end of the element and suggesting a polyadenylated RNA transposition intermediate. This 3' repeat region may have a structural role in heterochromatin. The most distal part of each complete HeT-A on the chromosome, the region 5' of the ORFs, has unusual conserved features, which might produce a terminal structure for the chromosome.

Amino Acid Sequence↗
PubMed1994

Hydrolytic stability of polyurethane medical adhesive dressings.

The present study deals with the effect of the type and chemical character of incorporated polyester (polyether blocks) on the hydrolytic stability of different types of polyurethane medical adhesive dressings. Diffusion parameters of the investigated polyurethane adhesives, giving information concerning the chemical changes taking place in water or physiological solution, have also been determined.

Adhesives↗
PubMed1993

Biocompatible and biodegradable polyurethane polymers.

This study deals with the opportunities for the synthesis of biocompatible and biodegradable polyurethane adhesives which are suitable for application as wound dressings. Three different synthetic possibilities have been investigated. The relationships between some reaction factors and the final properties of the obtained products are pointed out. The toxicity of the investigated urethane acrylates, polyurethanes and combined polyurethane adhesives is also studied.

Acrylates↗
PubMed1990

[The nephrotic syndrome as a consequence of Feloran treatment in a female patient with rheumatoid arthritis].

A case is presented of a 65 years old woman with a rheumatoid arthritis III stage who had developed a nephrotic syndrome due to the treatment with Feloran. The biopsy examination showed the pathomorphologic pattern of glomerulonephritis with minimum changes. The discontinuance of the Feloran treatment led to a full disappearance of the nephrotic syndrome. It is recommended that Feloran treatment should not be applied to patients with previous renal lesions.

Aged↗
PubMed1989

Expression of synthetic calcitonin genes in plasmid vectors containing tandemly repeated non-overlapping ribosome binding sites.

1. Expression plasmids containing non-overlapping tandemly repeated ribosome binding sites (RBS) were constructed in order to stabilize mRNA and enhance translation. 2. Two synthetic genes (human calcitonin tetramer gene and a fusion gene human gamma-interferon-human calcitonin) were cloned in these vectors and the effect of multiplicity of Shine-Dalgarno (S/D) sequence on heterologous gene expression was studied. 3. It was found that duplication and triplication of RBS had no effect on the stability of mRNA but led to a strong decrease in the level of recombinant protein and mRNA in the cell. 4. Plasmids bearing four times repeated S/D sequences gave longer-lived mRNAs and maintained a level of protein and mRNA very close to the values obtained with a single S/D containing plasmids.

Base Sequence↗