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T Pribyl

Publications and source records attributed to T Pribyl.

At least 19 recordsLinked to original sources
PubMed1999

Energetics and topology of CzcA, a cation/proton antiporter of the resistance-nodulation-cell division protein family.

The membrane-bound CzcA protein, a member of the resistance-nodulation-cell division (RND) permease superfamily, is part of the CzcCB(2)A complex that mediates heavy metal resistance in Ralstonia sp. CH34 by an active cation efflux mechanism driven by cation/proton antiport. CzcA was purified to homogeneity after expression in Escherichia coli, reconstituted into proteoliposomes, and the kinetics of heavy metal transport by CzcA was determined. CzcA is composed of 12 transmembrane alpha-helices and two large periplasmic domains. Two conserved aspartate and a glutamate residue in one of these transmembrane spans are essential for heavy metal resistance and proton/cation antiport but not for facilitated diffusion of cations. Generalization of the resulting model for the function of CzcA as a two-channel pump might help to explain the functions of other RND proteins in bacteria and eukaryotes.

Amino Acid Sequence↗
PubMed1999

CzcD is a heavy metal ion transporter involved in regulation of heavy metal resistance in Ralstonia sp. strain CH34.

The Czc system of Ralstonia sp. strain CH34 mediates resistance to cobalt, zinc, and cadmium through ion efflux catalyzed by the CzcCB(2)A cation-proton antiporter. The CzcD protein is involved in the regulation of the Czc system. It is a membrane-bound protein with at least four transmembrane alpha-helices and is a member of a subfamily of the cation diffusion facilitator (CDF) protein family, which occurs in all three domains of life. The deletion of czcD in a Ralstonia sp. led to partially constitutive expression of the Czc system due to an increased transcription of the structural czcCBA genes, both in the absence and presence of inducers. The czcD deletion could be fully complemented in trans by CzcD and two other CDF proteins from Saccharomyces cerevisiae, ZRC1p and COT1p. All three proteins mediated a small but significant resistance to cobalt, zinc, and cadmium in Ralstonia, and this resistance was based on a reduced accumulation of the cations. Thus, CzcD appeared to repress the Czc system by an export of the inducing cations.

Bacterial Proteins↗
PubMed1997

New functions for the three subunits of the CzcCBA cation-proton antiporter.

The membrane-bound CzcCBA protein complex mediates heavy metal resistance in Alcaligenes eutrophus by an active cation efflux mechanism driven by cation-proton antiport. The CzcA protein alone is able to mediate weak resistance to zinc and cobalt and is thus the central antiporter subunit. The two histidine-rich motifs in the CzcB subunit are not essential for zinc resistance; however, deletion of both motifs led to a small but significant loss of resistance to this cation. Translation of the czcC gene encoding the third subunit of the CzcCBA complex starts earlier than predicted, and CzcC is probably a periplasmic protein, as judged by the appearance of two bands after expression of czcC in Escherichia coli under control of the phage T7 promoter. Fusions of CzcC and CzcB with alkaline phosphatase and beta-galactosidase are in agreement with a periplasmic location of most parts of both proteins. Both CzcC and CzcB are bound to a membrane, probably the outer membrane, by themselves and do not need either CzcA or each other as an anchoring protein. Based on these data, a new working model for the function of the Czc system is discussed.

Alcaligenes↗
PubMed1993

[Treatment of acetabular fractures].

The authors present an account of 85 patients with fractures of the acetabulum treated at the Orthopaedic Clinic, Faculty Hospital Plzen in 1985-1991. The fractures are classified according to Lettournel-Judet. The authors investigated associated injuries which prolong the interval between injury and operation as well as the correlation between the mechanism of injury and the patient's age and the incidence of injuries in different months of the year. For indication for operation the quality of reposition evaluated by computed tomography is essential. The authors analyze the length of the interval between injury and operation, administration of antibiotics and anticoagulants. As to early complications, they pay attention in particular to bronchopneumonia, infection and thromboembolic disease. The paper deals also with the most serious late complication--avascular necrosis--and the authors discuss the causes of its development as well as possibilities to influence it. The paper presents also results evaluating patients as regards their return to work, subjective evaluation of gait, pain of the joints and satisfaction with treatment. The case-history is followed by discussion concerned with the importance of computed tomography, the surgical approach, importance of treatment of the sacroiliac complex, the development of heterotopic and ectopic ossifications and the essential time of relief of the operated joint. In the conclusion the authors summarize the basic principles of fractures of the acetabulum.

Acetabulum↗
PubMed1992

DM20 mRNA splice product of the myelin proteolipid protein gene is expressed in the murine heart.

Northern blot analysis of poly A(+) RNA isolated from mouse heart revealed the expression of 3.3 and 2.4 kb mRNAs that hybridized with a cDNA for the mouse proteolipid protein (PLP). In order to examine the relationship of these RNAs to the myelin PLP/DM20 mRNAs, a mouse heart cDNA library was prepared and screened with a mouse PLP cDNA. A cDNA was isolated, sequenced, and found to encode the DM20 variant of PLP. Polymerase chain reaction (PCR) analysis of heart cDNA with three sets of primers confirmed the presence of DM20 mRNA in mouse heart and indicated that it is the major splice product of the PLP gene expressed in that tissue. In situ hybridization localized the expression of the DM20 mRNA to the myocardial cells. Northern blot analysis indicated that expression of the DM20 mRNA is developmentally regulated in the murine heart, increasing significantly in concentration after 12 days postpartum. Northern analysis also revealed the expression of the DM20 mRNA in the hearts of the jimpy and quaking mutants. These results indicate that the PLP gene is expressed in tissues other than brain and support the concept that products of the PLP gene may have some biological role other than as structural components of myelin.

Animals↗
PubMed1991

Molecular analysis of a patient with neurofibromatosis 1 and achondroplasia.

The gene for von Recklinghausen neurofibromatosis (NF1) is on proximal 17q; the location of the gene for achondroplasia (ACH) is unknown. We have begun a molecular analysis of a patient with mental retardation, NF1 and ACH, a clinical presentation suggestive of a contiguous gene syndrome. In addition, this individual has a 47,XYY chromosome constitution. To define a possible chromosome 17 deletion, we investigated the copy number of DNA sequences linked to NF1 with conventional and pulsed-field gel electrophoresis (PFGE). We found no evidence for a deletion on chromosome 17. These results make it unlikely that this patient harbors a single deletion in the NF1 region causing both NF1 and ACH and suggest different mechanisms for the de novo occurrence of 2 autosomal dominant disorders in this individual.

Achondroplasia↗
PubMed1990

The achondroplasia gene is not linked to the locus for neurofibromatosis 1 on chromosome 17.

We have investigated genetic linkage of von Recklinghausen neurofibromatosis (NF1) and achondroplasia (ACH) using chromosome-17 markers that are known to be linked to NF1. Physical proximity of the two loci was suggested by the report of a patient with mental retardation and the de novo occurrence of both NF1 and ACH. Since the chance of de novo occurrence of these two disorders in one individual is 1 in 600 million, this suggested a chromosomal deletion as a single unifying molecular event and also that the ACH and NF1 loci might be physically close. To test this, we performed linkage analysis on a three-generation family with ACH. We used seven DNA probes that are tightly linked to the NF1 locus, including DNA sequences that are known to flank the NF1 locus on the centromeric and telomeric side. We detected two recombinants between the ACH trait and markers flanking the NF1 locus. In one recombinant, the flanking markers themselves were nonrecombinant. Multi-point linkage analysis excluded the ACH locus from a region surrounding the NF1 locus that spans more than 15 cM (lod score less than -2). Therefore, analysis of this ACH pedigree suggests that the ACH locus is not linked to the NF1 locus on chromosome 17.

Achondroplasia↗
PubMed1990

Serum amyloid A and P protein genes in familial Mediterranean fever.

Two recent studies have suggested the involvement of serum amyloid A (SAA) and P (APCS) genes in familial Mediterranean fever (MEF). To test the role of SAA and APCS in MEF and MEF-amyloidosis, we studied 17 informative families (15 Armenians, 2 non-Ashkenazi Jews) and 8 MEF patients with amyloidosis using a candidate gene approach. No evidence for any MEF-associated polymorphism was found in any of the 41 Armenian and Jewish MEF patients tested. Our family studies allowed us to rule out tight linkage between SAA and MEF (lod score = -2.16, theta less than or equal to 0.06). For APCS we found that the allele frequency in the MEF-amyloidosis patients was similar to that in 18 unrelated MEF patients without amyloidosis and their 33 healthy parents. Finally, we excluded close genetic linkage between APCS and MEF at 8.5 cM or less (lod score = -2.2).

Alleles↗
PubMed1989

[Properties of silver-containing rat ceruloplasmin].

Ceruloplasmin (Cp) was isolated from the sera of albino rats fed with silver nitrate (60 mg/kg of body weight). The oxidase activity of the enzyme was sharply decreased, while its concentration in the blood (as assayed immunologically) was slightly lower than in controls. The drop in the oxidase activity was caused by the replacement of several coppers by silver ions in the Cp molecule. Ag-Cp contained about four silver atoms per 1 mole of protein, its spectrum lacking maxima at 450 and 610 nm that are typical of normal Cp. When subjected to PAAG electrophoresis, Ag-Cp displayed two bands, one of which (Ag-Cp2) had the anodic mobility of normal Cp. The other band (Ag-CpI) migrated at a slower rate. Both bands were separately subjected to SDS-PAAG electrophoresis which revealed the dissimilarities among the proteolytic fragment patterns of Ag-CpI, Ag-Cp2 and normal Cp. Both Ag-CpI and Ag-Cp2 contained peculiar fragments produced by spontaneous limited proteolysis of the native molecule. The binding of silver ions by Cp seems to alter significantly the molecule conformation, which may cause the exposure of new peptide bonds susceptible to proteolytic attack. Cp seems to participate in the binding and detoxication of heavy metals in mammals.

Animals↗
PubMed1987

Dopaminergic antagonists potentiate the adenohypophyseal growth reaction to oestrogen: thioridazine is less effective than perphenazine.

The injection of oestradiol benzoate as an aqueous microcrystal suspension, in a dose of 1 mg twice a week, evokes a marked adenohypophyseal growth reaction in male rats. The reaction is potentiated by dopaminergic antagonists from the group of neuroleptics (specifically perphenazine and thioridazine). Elicitation of the same adenohypophyseal reaction required twice as much thioridazine (10 mg/rat per day) as perphenazine. Thyroxine inhibited the adenohypophyseal growth reaction to oestradiol. The serum polyphenol oxidase (ceruloplasmin) level rose after oestradiol and perphenazine and thioridazine slightly potentiated the increase.

Animals↗
PubMed1984

Radioactive 86rubidium influx into red blood cells in essential hypertension in relation to the plasma renin activity.

Changes in several mechanisms of sodium transport across the cell membranes are described in essential hypertension. We studied ouabain-sensitive and insensitive 86Rb+ influx into the red blood cells (RBC) of 16 healthy controls and 51 patients with essential hypertension (EH) divided according to their plasma renin activity (PRA) in 3 groups: 11 patients with high PRA (HREH), 18 patients with normal PRA (NREH) and 22 patients with low PRA (LREH). In addition to studying 86RB+ uptake by patients RBC, we tested also the effect of the patients' sera on 86Rb+ influx into the RBC of healthy subjects. Red blood cells of patients with HREH and NREH had lower ouabain-sensitive 86Rb+ influx in comparison with controls. No significant differences were found between these hypertensive groups. In contrast 86Rb+ uptake by the RBC of LREH patients was always higher than in controls or HREH and NREH. It was chiefly the ouabain-sensitive component that was raised, but some increase in ouabain-insensitive 86Rb+ influx also could be seen. The serum of patients with HREH and NREH, when incubated with RBC of healthy controls, lowered their ouabain-sensitive 86Rb+ influx. The decrease was more pronounced in NREH than in HREH group. Plasma from LREH patients increased both ouabain-sensitive and ouabain-insensitive 86Rb+ influx into the control RBC. These findings indicate that there may be differences in the sodium/potassium transport mechanisms across the cell membrane in various kinds of EH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Metoclopramide potentiates the hypophyseal reactions to oestradiol.

Male rats to which oestradiol benzoate was administered intramuscularly twice a week for three weeks in 1 mg doses as an aqueous microcrystal suspension showed an increase in adenohypophyseal weight, in the number of lactotropic cells in the adenohypophysis (demonstrated by immunohistochemical detection of prolactin) and in polyphenol oxidase (ceruloplasmin) activity in the blood and hypothalamus. The simultaneous administration of metoclopramide (methoxychloroprocainamide) in doses of 10 mg/rat per day in food potentiated the adenohypophyseal reaction to oestradiol (weight and the number of lactotropic cells), but potentiated the polyphenol oxidase reaction only little or not at all. Metoclopramide thus has an anti-dopaminergic effect similar to that of perphenazine and other inhibitors of dopaminergic neurones.

Animals↗
PubMed1984

Modulation of the effect of oestradiol on adenohypophyseal weight: ineffectiveness of nickel chloride, potentiation by cimetidine.

Male rats received an i.m. injection of oestradiol benzonate twice a weak, as an aqueous microcrystal suspension in doses of 1 mg, and/or were given, in their food, nickel chloride in daily doses of 10 mg [first experiment] or 20 mg [second experiment] per rat, or cimetidine, an antagonist of H2 receptors, in daily doses of 20 mg [first experiment] or 40 mg [second experiment] per rat. Neither dose of nickel chloride affected the oestrogen-induced growth reaction of the adenohypophysis, the increase in polyphenol oxidase [ceruloplasmin] activity in the blood [the larger dose stimulated it slightly], the increase in hypothalamic polyphenol oxidase activity or the post-oestrogen drop in the hypothalamic ascorbic acid concentration. Both doses of cimetidine potentiated the growth reaction of the adenohypophysis to oestrogens, but did not affect the blood polyphenol oxidase, the hypothalamic polyphenol oxidase or the hypothalamic ascorbic acid reaction. If administered alone, the larger dose of cimetidine mildly reduced serum polyphenol oxidase [ceruloplasmin] activity.

Animals↗
PubMed1983

Reflections on what makes the heart grow.

Under conditions of experimental cardiac overload and hypertrophy in rats, a digoxinlike immunoreactivity appears in their serum which is correlated with cardiac growth. It is hypothesized that this is caused by the presence of an endogenous cardiotropic factor displaying cross immunoreactivity with digoxin. Additional evidence of the existence of the putative cardiotropic factor is provided by the finding that the sera of rats with cardiac overload displaying digoxinlike immunoreactivity stimulate the multiplication of rat cardiac myocytes in the tissue culture. This factor may be an adrenal steroid different from corticosterone and aldosterone. The name endocardin or endocardiotonin for this substance is suggested.

Adrenal Glands↗
PubMed1983

Inhibition of the oestradiol-induced increase in adenohypophyseal weight and in hypothalamic and serum polyphenol oxidase activity by dopaminergic agonists.

The administration of oestradiol (oestradiol benzoate as an aqueous microcrystal suspension, Agofolin depot SPOFA, 1 mg i.m. twice a week) leads in rats to an increase in adenohypophyseal weight and in polyphenol oxidase activity in the serum (ceruloplasmin) and in the base of the brain (the floor of the third ventricle). The simultaneous peroral administration of the ergoline derivatives D-6-methyl-8-ergoline-(i)-yl acetic acid amide (Deprenon SPOFA) or N-(D-6-methyl-8-isoergolenyl)-N',N'-diethyl carbamide hydrogen maleate (lisuride, Lysenyl SPOFA) in a dose of 200 micrograms/rat/day markedly inhibited all three reactions. The two derivatives were equally effective. Inhibition of the increase in hypothalamic polyphenol oxidase activity, with resultant reduced disintegration of hypothalamic dopamine, may play a role in the mechanism of inhibition of the pituitary reaction to oestradiol caused by dopaminergic agonists. The agonists can also, of course, act like dopamine in the adenohypophysis itself.

Animals↗
PubMed1983

[Blockade of estradiol benzoate hyperplasia of the adenohypophysis with Deprenon and lisuride - histological findings].

Three-week administering of Estradiolbenzoate to male rats results in hyperplasia of adenohypophysis with increase of Orange G slightly positive cells and chromophobe cells, loosening of structure giving a trabecular picture, and stressed vascularization. Simultaneous administering of Ergoline compounds (Deprenon, Lisuride) rather limited the transformation. However, the differentiation of single pituitary cells due to Estradiolbenzoate remained substantially uninfluenced.

Animals↗
PubMed1982

Inhibition by an ergoline derivative (dopaminergic agonist) of oestradiol-induced adenohypophyseal growth and of the decrease in the hypothalamic ascorbic acid (HAA) concentration in rats.

The increase in adenohypophyseal weight and the decrease in the ascorbic acid concentration in the hypothalamus of rats injected i.m. twice a week with oestradiol benzoate as an aqueous microcrystal suspension in doses of 2.65 mumol (1 mg) was completely (HAA) or almost completely (adenohypophyseal weight) inhibited by the simultaneous administration of the ergoline derivative D-6-methyl-8-ergoline-(1)-yl acetic acid amide (Deprenon SPOFA) in the diet in daily doses of 0.28 mumol (200 micrograms) per rat. The functional significance of HAA in dopaminergic modulation of oestrogen-induced adenohypophyseal growth is discussed, with special reference to the possible function of HAA as a dopamine-beta-hydroxylase cofactor.

Animals↗