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Biomedical subjects

M Pál

Publications and source records attributed to M Pál.

14 recordsLinked to original sources
PubMed2001

Chemoenzymatic synthesis of 2-chloro-4-nitrophenyl beta-maltoheptaoside acceptor-products using glycogen phosphorylase b.

In the present work, we aimed at developing a chemoenzymatic procedure for the synthesis of beta-maltooligosaccharide glycosides. The primer in the enzymatic reaction was 2-chloro-4-nitrophenyl beta-maltoheptaoside (G(7)-CNP), synthesised from beta-cyclodextrin using a convenient chemical method. CNP-maltooligosaccharides of longer chain length, in the range of DP 8-11, were obtained by a transglycosylation reaction using alpha-D-glucopyranosyl-phosphate (G-1-P) as a donor. Detailed enzymological studies revealed that the conversion of G(7)-CNP catalysed by rabbit skeletal muscle glycogen phosphorylase b (EC 2.4.1.1) could be controlled by acarbose and was highly dependent on the conditions of transglycosylation. More than 90% conversion of G(7)-CNP was achieved through a 10:1 donor-acceptor ratio. Tranglycosylation at 37 degrees C for 30 min with 10 U enzyme resulted in G(8-->12)-CNP oligomers in the ratio of 22.8, 26.6, 23.2, 16.5, and 6.8%, respectively. The reaction pattern was investigated using an HPLC system. The preparative scale isolation of G(8-->11)-CNP glycosides was achieved on a semipreparative HPLC column. The productivity of the synthesis was improved by yields up to 70-75%. The structures of the oligomers were confirmed by their chromatographic behaviours and MALDI-TOF MS data.

Acarbose↗
PubMed2001

Top-DER- and Dpp-dependent requirements for the Drosophila fos/kayak gene in follicular epithelium morphogenesis.

The Drosophila fos (Dfos)/kayak gene has been previously identified as a key regulator of epithelial cell morphogenesis during dorsal closure of the embryo and fusion of the adult thorax. We show here that it is also required for two morphogenetic movements of the follicular epithelium during oogenesis. Firstly, it is necessary for the proper posteriorward migration of main body follicle cells during stage 9. Secondly, it controls, from stage 11 onwards, the morphogenetic reorganization of the follicle cells that are committed to secrete the respiratory appendages. We demonstrate that DER pathway activation and a critical level of Dpp/TGFbeta signalling are required to pattern a high level of transcription of Dfos at the anterior and dorsal edges of the two groups of cells that will give rise to the respiratory appendages. In addition, we provide evidence that, within the dorsal-anterior territory, the level of paracrine Dpp/TGFbeta signalling controls the commitment of follicle cells towards either an operculum or an appendage secretion fate. Finally, we show that Dfos is required in follicle cells for the dumping of the nurse cell cytoplasm into the oocyte and the subsequent apoptosis of nurse cells. This suggests that in somatic follicle cells, Dfos controls the expression of one or several factors that are necessary for these processes in underlying germinal nurse cells.

Animals↗
PubMed2000

[Short- and long-term changes in left ventricular function after surgical correction of mitral regurgitation].

After surgical treatment of mitral regurgitation (MR) left ventricular dysfunction (LVD) can appear, which is an important predictive factor of long-term morbidity and mortality. The aim of our retrospective study was the assessment of left ventricular function (LVF) with M-mode echo measurement in the early and late postoperative period. Between 01. 01. 1992. and 31. 12. 1996. 70 patients with MR (29 men, 41 women, mean age 53.8 years) had at least three M-mode echoes: before surgery (I.), after surgery within 1 year (II.) and after the first postoperative year (mean 2.4 years) (III.). The patients were divided into subgroups: a) prosthetic valve replacement (MB) 58 patients, valvuloplasty (PL) 12 patients, b) coronary bypass grafting (C) 12 patients, no coronary disease (NC) 58 patients, c) chordal rupture (R) 24 patients, other etiology (NR) 46 patients. The evaluation of LVF was based on the ejection fraction (EF) calculated from the end-diastolic (Dd) and end-systolic (Ds) diameters on M-mode echo. Statistical analysis was made by paired and unpaired t test and with correlation analysis. The Dd decreased in the whole group (T) and in all subgroups in the II. and III. measurements compared to the I. (T: 58.9 vs. 52.6 vs. 53.2 mm; p < 0.0001, p < 0.0001). The Ds did not change in any group. In all groups except C the EF decreased at the II. measurement compared to the I. values (T: 57.7 vs. 47.8%, p < 0.0001; MB: 56.6 vs. 46.6%, p < 0.0001; PL: 62.8 vs. 53.8%, p = 0.05; NC: 59.6 vs. 48.3%, p < 0.0001; R: 61.5 vs. 50.4%, p < 0.0003; NR: 55.6 vs. 46.5% p = 0.0002), and it remained significantly lower in the III. measurement as well. At the III. measurement the EF was below 55% in all groups. In the groups T, MB, NC, NR the EF increased at the III. measurement compared to the II. (W: 47.8 vs. 51.3%, p = 0.002; PVR: 46.6 vs. 51.4%, p = 0.001; NC: 48.3 vs. 52.8%, p = 0.005; NR: 46.5 vs. 49.9%, p = 0.05). In the group C the I., II., III. EF values were not significantly different. There were 33 patients with preoperative EF more than 60%. In this group the EF decreased at the II. measurement, but the III. measurement showed normalization of the EF (67.03 vs. 52.58 vs. 59.27%, p < 0.0001, p < 0.01). There was no strong correlation between the preoperative EF, Ds and early or late postoperative EF (r = 0.54, r = -0.58; r = 0.62, r = -0.56). In patients operated for MR the postoperative EF is diminished independently on the preoperative EF, the operative technique or etiology. Left ventricular dysfunction concealed by the volume overload is unmasked by the decreased EF in the early postoperative period. LVD is partly reversible in the majority of the cases, however complete reversibility takes place only in cases with preoperative EF over 60%. Hence the operation of MR in patients with EF less than 60% is considered to be too late for the reversibility of LVD.

Adult↗
PubMed2000

Genetic and molecular analysis in the 70CD region of the third chromosome of Drosophila melanogaster.

A collection of lethal and semi-lethal P-element insertions in the 70CD region of chromosome 3 of Drosophila melanogaster was used to investigate genes and gene arrangements by a combination of genetic, cytological, functional and molecular methods. The 12 lethal insertions studied fall into seven complementation groups of six genes. Lethal phases, expression patterns and other phenotypic aspects of these genes were determined. The genes and additional available sequences were placed on cloned genomic DNA fragments and arranged in an EcoRI map of 150kb that covers approximately the bands 70C7-8 to 70D1. Determination of deficiency breakpoints links the genetic, physical and molecular data. The sequences adjacent to seven independent P-element insertions were established after plasmid rescue or polymerase chain reaction. Similarity searches allowed the assignment of the P-element insertions to known mutations, expressed sequence tags, sequence tagged sites, or homologous genes of other species. Among these were identified a putative transacylase, a putative cell cycle gene, and the gene responsible for the dominant Polycomb-suppressor phenotype of devenir. The genomic sequence of the l(3)70Ca/b gene reveals a novel heat shock protein (hsc70Cb). l(3)70Da was identified as a member of the CDC48/PEX1 ATPase family and its coding sequence was determined.

Acyltransferases↗
PubMed1998

Capillary blood flow and tissue metabolism in skeletal muscle during sympathetic trunk stimulation.

NADH fluorescence at tissue sites 15-20 microns in diameter and red blood cell velocity in adjacent capillaries were measured in resting sartorius muscle of the anesthetized cat during a 3-min period of sympathetic trunk stimulation. At stimulation frequencies of 2 and 4 Hz, red blood cell velocity fell briefly to 30-40% of control and then returned to approximately 75% of control values (vascular escape). No change in NADH fluorescence was observed. With stimulus frequencies of 6-12 Hz, flow reduction was greater and led to an increase in fluorescence when the flow reduction was > 50% and was sustained for > 30 s. NADH changes were more pronounced at tissue sites near venous capillaries than at sites near arterial capillaries. Hyperemia ensued after the end of sympathetic stimulation only when NADH fluorescence rose during stimulation. Resting blood flow in this muscle appears to be well above the minimum required to support oxidative metabolism. A shift to anaerobic metabolism does not appear to cause vascular escape during sympathetic stimulation but appears to be required for poststimulation hyperemia. These observations suggest that two separate oxygen-dependent mechanisms elicit vasodilation during and after sympathetic trunk stimulation.

Animals↗
PubMed1997

P-element insertion alleles of essential genes on the third chromosome of Drosophila melanogaster: correlation of physical and cytogenetic maps in chromosomal region 86E-87F.

We have established a collection of 2460 lethal or semi-lethal mutant lines using a procedure thought to insert single P elements into vital genes on the third chromosome of Drosophila melanogaster. More than 1200 randomly selected lines were examined by in situ hybridization and 90% found to contain single insertions at sites that mark 89% of all lettered subdivisions of the Bridges' map. A set of chromosomal deficiencies that collectively uncover approximately 25% of the euchromatin of chromosome 3 reveal lethal mutations in 468 lines corresponding to 145 complementation groups. We undertook a detailed analysis of the cytogenetic interval 86E-87F and identified 87 P-element-induced mutations falling into 38 complementation groups, 16 of which correspond to previously known genes. Twenty-one of these 38 complementation groups have at least one allele that has a P-element insertion at a position consistent with the cytogenetics of the locus. We have rescued P elements and flanking chromosomal sequences from the 86E-87F region in 35 lines with either lethal or genetically silent P insertions, and used these as probes to identify cosmids and P1 clones from the Drosophila genome projects. This has tied together the physical and genetic maps and has linked 44 previously identified cosmid contigs into seven "super-contigs" that span the interval. STS data for sequences flanking one side of the P-element insertions in 49 lines has identified insertions in the alphagamma element at 87C, two known transposable elements, and the open reading frames of seven putative single copy genes. These correspond to five known genes in this interval, and two genes identified by the homology of their predicted products to known proteins from other organisms.

Alleles↗
PubMed1997

P-element insertion alleles of essential genes on the third chromosome of Drosophila melanogaster: mutations affecting embryonic PNS development.

To identify novel genes and to isolate tagged mutations in known genes that are required for the development of the peripheral nervous system (PNS), we have screened a novel collection of 2460 strains carrying lethal or semilethal P element insertions on the third chromosome. Monoclonal antibody 22C10 was used as a marker to visualize the embryonic PNS. We identified 109 mutant strains that exhibited reproducible phenotypes in the PNS. Cytological and genetic analyses of these strains indicated that 87 mutations affect previously identified genes: tramtrack (n = 18 alleles), string (n = 15), cyclin A (n = 13), single-minded (n = 13), Delta (n = 9), neuralized (n = 4), pointed (n = 4), extra macrochaetae (n = 4), prospero (n = 3), tartan (n = 2), and pebble (n = 2). In addition, 13 mutations affect genes that we identified recently in a chemical mutagenesis screen designed to isolate similar mutants: hearty (n = 3), dorsotonals (n = 2), pavarotti (n = 2), sanpodo (n = 2), dalmatian (n = 1), missensed (n = 1), senseless (n = 1), and sticky ch1 (n = 1). The remaining nine mutations define seven novel complementation groups. The data presented here demonstrate that this collection of P elements will be useful for the identification and cloning of novel genes on the third chromosome, since >70% of mutations identified in the screen are caused by the insertion of a P element. A comparison between this screen and a chemical mutagenesis screen undertaken earlier highlights the complementarity of the two types of genetic screens.

Alleles↗
PubMed1996

[Cholesterol levels in young men and women planning conception].

The purpose of this study is to incorporate the primary prevention of coronary heart disease into a periconception care. Among others total cholesterol was determined in 2610 female and 2307 male participants. The mean (+/- S.D.) of total cholesterol was 4.93 +/- 1.04 in females and 5.20 +/- 1.24 mmol/l in males. Only 7.9% of females and 4.7% of males had previous knowledge about their high total cholesterol. Three month later 1.08 mmol/l (16%) and 1.18 mmol/l (18%) reduction was found in total cholesterol of participants with > 6.5 mmol/l due to education programme including change in diet, to stop smoking, etc.

Adult↗
PubMed1993

A computer controlled system for multiple site microcirculatory measurements.

A system has been developed for intravital microscopy studies that records optical signals at different tissue sites together with X-Y coordinates within an area of up to 100 cm2. Z axis coordinates can also be recorded. The system utilizes a computer and a motor-driven microscope stage to rapidly and repetitively move between selected sites. The system can also be used to map topological features and geometry. The application of the system to study spatial heterogeneity of changes in tissue metabolism with time and to map vascular network architecture is described.

Animals↗
PubMed1992

[Relationship between weight increase during pregnancy and weight of the newborn].

The data of first 1000 first-born, non-malformed, mature (greater than or equal to 2500 g) offspring of participants in the Hungarian "Optimal" Family Planning Programme were evaluated. The mean maternal weight gain during pregnancy was 13 kg which was modified by the body weight of women. Maternal weight gain exceeded 13 kg in 54% of pregnant women. There was an obvious positive correlation between maternal weight gain and birth weight which was calculated as 26.6 g/kg.

Birth Weight↗
PubMed1992

Maternal weight gain and birth weight.

The data of first 1000 non-malformed, mature (greater than or equal to 2500 g) singletons of participants in the Hungarian Family Planning Programme were evaluated. The mean maternal weight gain during pregnancy was 13 kg which was modified by the body weight of women. Maternal weight gain exceeded 13 kg in 54% of pregnant women. There was a positive correlation between maternal weight gain and birth weight which was calculated as 26.6 g/kg.

Adult↗