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M Molnar

Publications and source records attributed to M Molnar.

47 records · Page 3Linked to original sources
PubMedDate not supplied

Polyploidy in the haplontic yeast Schizosaccharomyces pombe: construction and analysis of strains.

The fission yeast Schizosaccharomyces pombe has a haplontic life cycle in which the diplophase is confined to the zygote. Through the use of one- and two-step protoplast fusions we show that the ploidy can be increased up to pentaploid. The polyploid fusion products are rather unstable and segregate cells of lower ploidies by gradual loss of chromosomes during mitotic divisions. The polyploid cells conjugate normally but are prone to arrest at various stages of meiosis (1-, 2- and 3-spored asci, binucleate spores) and/or produce inviable, most probably aneuploid, spores. Marker segregation in the complete tetrads indicates the multiple association of homologous chromosomes. In tetra- and penta-ploid meiosis, multispored (6- to 7-spored) asci are also produced, probably by postmeiotic division of the nuclei.

Cloning, Molecular↗
PubMedDate not supplied

Prognostic value of fluorescein angiography of the funds in diabetic children.

A positive fluorescein angiographic (FLAG) finding is a frequent occurrence in ophthalmoscopically negative cases. By repeated FLAG examinations good follow-up of the variability of the finding is possible. After 4--8 years of diabetes, ophthalmoscopically diagnosable retinopathy is to be expected in the patients in whom the initial FLAG examination showed signs of angiopathy.

Adolescent↗
PubMedDate not supplied

Application of chaos theory to biology and medicine.

The application of "chaos theory" to the physical and chemical sciences has resolved some long-standing problems, such as how to calculate a turbulent event in fluid dynamics or how to quantify the pathway of a molecule during Brownian motion. Biology and medicine also have unresolved problems, such as how to predict the occurrence of lethal arrhythmias or epileptic seizures. The quantification of a chaotic system, such as the nervous system, can occur by calculating the correlation dimension (D2) of a sample of the data that the system generates. For biological systems, the point correlation dimension (PD2) has an advantage in that it does not presume stationarity of the data, as the D2 algorithm must, and thus can track the transient non-stationarities that occur when the systems changes state. Such non-stationarities arise during normal functioning (e.g., during an event-related potential) or in pathology (e.g., in epilepsy or cardiac arrhythmogenesis). When stochastic analyses, such as the standard deviation or power spectrum, are performed on the same data they often have a reduced sensitivity and specificity compared to the dimensional measures. For example, a reduced standard deviation of heartbeat intervals can predict increased mortality in a group of cardiac subjects, each of which has a reduced standard deviation, but it cannot specify which individuals will or will not manifest lethal arrhythmogenesis; in contrast, the PD2 of the very same data can specify which patients will manifest sudden death. The explanation for the greater sensitivity and specificity of the dimensional measures is that they are deterministic, and thus are more accurate in quantifying the time-series. This accuracy appears to be significant in detecting pathology in biological systems, and thus the use of deterministic measures may lead to breakthroughs in the diagnosis and treatment of some medical disorders.

Animals↗
PubMedDate not supplied

The point correlation dimension: performance with nonstationary surrogate data and noise.

The dynamics of many biological systems have recently been attributed to low-dimensional chaos instead of high-dimensional noise, as previously though. Because biological data are invariably nonstationary, especially when recorded over a long interval, the conventional measures of low-dimensional chaos (e.g., the correlation dimension algorithms) cannot be applied. A new algorithm, the point correction dimension (PD2i) was developed to deal with this fundamental problem. In this article we describe the details of the algorithm and show that the local mean PD2i will accurately track dimension in nonstationary surrogate data.

Algorithms↗
PubMedDate not supplied

Preproenkephalin messenger RNA-containing amacrine cells in the chicken retina identified with in situ hybridization histochemistry.

Enkephalin peptides are present in the retina of several vertebrate species. In the avian retina, enkephalin immunoreactivity is primarily localized to a population of amacrine cells. In the present study, we determined the localization of cells expressing preproenkephalin (PPE) mRNA, which encodes the precursor of enkephalin peptides, in adult as well as in embryonic chicken retinas. The localization of PPE mRNA-expressing cells to the proximal inner nuclear layer (INL) in the adult chicken retina is similar to that of enkephalin-immunoreactive cells observed in previous studies, indicating that amacrine cells expressing PPE mRNA synthesize Met5- and Leu5-enkephalin peptides and related extended forms. Specific hybridization signal is absent in retinas at embryonic day (E) 11, but it is detected in retinas at E 15 and at hatching. PPE mRNA-expressing cells at these ages are located in the proximal INL, and they can be classified as amacrine cells on the basis of their soma size and laminar position. These findings confirm and extend previous observations on the presence of opioid peptides in amacrine cells of the chicken retina. The presence of PPE mRNA at embryonic ages, together with the evidence that enkephalins influence developmental processes, suggests that these peptides modulate retinal maturation in birds.

Animals↗
PubMedDate not supplied

Personality, stress, and injuries in professional ballet dancers.

Twenty-nine soloist and principal dancers (mean age, 29.08 years) from America's two most celebrated ballet companies were administered questionnaires measuring personality (API), occupational stress (OES), strain (PSQ), and coping mechanisms (PRQ), and injury patterns. The results revealed that male dancers demonstrated significantly more negative personality traits and psychological distress than female dancers or men in the general population. In addition, physical stress and personality traits, characteristic of the "overachiever," distinguished injured dancers. It is suggested that classical ballet's emphasis on the ballerina may be at odds with a masculine identity in male dancers. Furthermore, the qualities that lead to success in this profession may contribute to injuries if carried to an extreme.

Adult↗
PubMedDate not supplied

A profile of the musculoskeletal characteristics of elite professional ballet dancers.

Twenty-eight principal dancers and soloists from America's two most famous ballet companies were examined for anthropometric measurements, including flexibility, muscle strength, and joint range of motion. Both male and female dancers were flexible, but not hypermobile, and did not differ significantly from each other. Marked differences were found between the range of motion of the hip and ankle in the dancers and the norms for the general population. The increased external rotation of the hip in women was accompanied by a loss in internal rotation, resulting in an increased range of motion with an externally rotated orientation. The men, however, lost more internal rotation than they gained in external rotation. These data raise the possibility of a torsional component to the turned-out hip position in elite female professional ballet dancers. In addition, significant anatomic differences separate elite dancers of both sexes from the normal population.

Adult↗
PubMedDate not supplied

[Non-culturable Koch bacilli during antitubercular chemotherapy].

The authors have performed 58435 microscopic examinations, of which 3813 were positive, and found 209 (5,48%) cases of non-cultivable Koch bacilli. The major bacteriological, clinico-evolutive and therapeutical aspects are examined. Most of the cases showing a syndrome of positive homogenate with a negative culture were rather recent ones (an evolution of less than 2 years in 73,68% of the total) and the highest frequency was found in those in which the treatment was in its first year. No direct relationship could be demonstrated between the number of germs (the Gaffky scale) and the frequency of the syndrome. The factors influencing the occurrence and the development of the syndrome are: the structure of the lesions, the method of bacteriologic examination, the therapy applied, and a certain immunologic reactivity. According to the authors the significance of this syndrome is positive in most of the cases, indicating a regression that has not been completed. The most reasonable attitude is a differentiated one, depending on each case, integrating the data obtained by the bacteriological examination in the therapeutic and evolutive clinico-radiologic context.

Antitubercular Agents↗
PubMedDate not supplied

Rape report challenged.

Explore the source record for details and available documents.

Bosnia and Herzegovina↗
PubMedDate not supplied

Mitochondrial cytochrome b gene deletion in Kearns-Sayre syndrome associated with a subclinical type of peripheral neuropathy.

Kearns-Sayre syndrome (KSS) is a progressive neuromuscular disease characterized by ophthalmoplegia, cardiac conduction block, and pigmentary retinopathy associated with abnormal mitochondrial structure and function. Usually mitochondrial DNA (mtDNA) deletions have been associated with Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia. Size and position of the deletions differ markedly among these patients. The present study confirms this observation for a patient with KSS by a muscle and nerve biopsy in which we detected a 1.2 kb mtDNA deletion. The location of the deletion, however, is unusual in this case: its position comprises nucleotides 14952 to 15739. The defect is heteroplasmic and concerns the cytochrome b and tRNA genes. Complex I and IV of the respiratory chain were intact in this case, indicating that below a threshold of tRNA formation, the impaired biosynthesis and membrane integration of one respiratory complex may cause the phenotypical appearance of the KSS syndrome associated with a subclinical neuropathy.

Adult↗