PubMed Health⌕ Search

Biomedical subjects

M Rudnicki

Publications and source records attributed to M Rudnicki.

At least 19 recordsLinked to original sources
PubMed2006

Gene expression profiles of human proximal tubular epithelial cells in proteinuric nephropathies.

In kidney disease renal proximal tubular epithelial cells (RPTEC) actively contribute to the progression of tubulointerstitial fibrosis by mediating both an inflammatory response and via epithelial-to-mesenchymal transition. Using laser capture microdissection we specifically isolated RPTEC from cryosections of the healthy parts of kidneys removed owing to renal cell carcinoma and from kidney biopsies from patients with proteinuric nephropathies. RNA was extracted and hybridized to complementary DNA microarrays after linear RNA amplification. Statistical analysis identified 168 unique genes with known gene ontology association, which separated patients from controls. Besides distinct alterations in signal-transduction pathways (e.g. Wnt signalling), functional annotation revealed a significant upregulation of genes involved in cell proliferation and cell cycle control (like insulin-like growth factor 1 or cell division cycle 34), cell differentiation (e.g. bone morphogenetic protein 7), immune response, intracellular transport and metabolism in RPTEC from patients. On the contrary we found differential expression of a number of genes responsible for cell adhesion (like BH-protocadherin) with a marked downregulation of most of these transcripts. In summary, our results obtained from RPTEC revealed a differential regulation of genes, which are likely to be involved in either pro-fibrotic or tubulo-protective mechanisms in proteinuric patients at an early stage of kidney disease.

Aged↗
PubMed2006

Protective effects of Passiflora alata extract pretreatment on carbon tetrachloride induced oxidative damage in rats.

The leaf extract of Passiflora alata Dryander (P. alata) has been demonstrated to possess antioxidant activity in vitro. The aim of this study was to investigate the effects of P. alata leaf extract pretreatment on carbon tetrachloride-treated rats. Male Wistar rats were randomly allocated into four groups: group 1 (control - vehicle), group 2 and 3 (P. alata extract - 1 and 5mg/kg, respectively) and group 4 (trolox - 0.18mg/kg). Rats received daily pretreatment by oral gavage for 30 days followed by a single dose of CCl(4) (3ml/kg i.p. in vegetable oil) on the 30th day and were killed after 6h. The pretreatment with the P. alata extract provided significant protection to liver, evidenced by lower degree of necrosis, decreased lipid peroxidation (TBARS) and higher catalase and superoxide dismutase activities. Additionally, pretreated-rats with P. alata (5mg/kg) showed significantly decreased cardiac TBARS levels. Our results indicate that a low oral dose of P. alata leaf extract has both hepato and cardioprotective effects on rats treated with CCl(4).

Animals↗
PubMed2003

Immunoglobulin light chains modulate polymorphonuclear leucocyte apoptosis.

BACKGROUND: Apoptosis of polymorphonuclear leucocytes (PMNLs) is important for the resolution of inflammation. Recently, we demonstrated that glucose-modified proteins increase PMNL apoptosis. No protein factors in sera of uraemic patients attenuating PMNL apoptosis have been identified to date. MATERIALS AND METHODS: We tested the influence of commercially available monoclonal immunoglobulin light chains (IgLCs) from multiple myeloma patients and polyclonal IgLCs isolated from haemodialysis patients, previously shown to modulate PMNL functions and to contribute to their prestimulation, on PMNL apoptosis. We detected morphological changes, DNA strand breaks and the loss of DNA content. RESULTS: All three apoptosis assays showed that kappa and lambda type IgLCs increase the percentage of viable PMNLs by inhibiting apoptosis in a concentration-dependent manner. The effect of IgLCs was abolished by specific antibodies. Addition of genistein abolished the reduction of PMNL apoptosis by IgLCs, suggesting that IgLCs exert their effect via tyrosine phosphorylation. Furthermore, we showed that the inhibition of caspase-3 activity is involved in the decrease of PMNL apoptosis. CONCLUSION: In concentrations present in sera of uraemic patients IgLCs could interfere with the normal resolution of inflammation and thereby contribute to the chronic inflammatory state found in end-stage renal disease patients.

Apoptosis↗
PubMed2003

Pharmacogenomics of angiotensin converting enzyme inhibitors in renal disease--pathophysiological considerations.

Angiotensin converting enzyme (ACE) inhibitors preserve native kidney function in patients with renal disease better than other antihypertensive drugs, most likely because they more effectively reduce proteinuria. The plasma concentration of the ACE inhibitors target is, at least in part, under genetic control. A polymorphism of the ACE gene based on the presence or absence of a 287 base pair element in intron 16 accounts for 47% of the total phenotypic variance in the plasma ACE levels of healthy individuals. Unfortunately, pharmacogenetic studies performed so far do not provide a clear answer as to whether the efficacy of the reduction of proteinuria by ACE inhibitors is influenced by the ACE genotype - probably because these studies were not primarily designed to answer this question. This paper will try to outline some aspects that should be considered before an appropriate study on this topic is initiated.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2002

Influence of blood sampling techniques on ionized magnesium level.

The aim of the study was to evaluate whether different blood sampling techniques (venous vs. capillary) influence the level of ionized magnesium. A total of 12 men and 20 women were included. A venous blood sample was collected from the antecubital vein without stasis in syringes containing 50 IU/ml electrolyte balanced heparin. Capillary tubes containing sodium heparin 50 IU/ml were used for blood sampling (150 microl) from the earlobe. A statistically significant difference between venous and capillary ionized magnesium at actual pH (0.57+/-0.04 vs. 0.55+/-0.04 mmol/L, p<0.05) was observed, whereas no difference was seen between adjusted ionized magnesium. No difference was observed between venous and capillary ionized calcium at actual pH or adjusted to pH 7.4. The pH level was significantly higher in capillary blood (7.44+/-0.02 vs. 7.48+/-0.02. p<0.00001). The higher pH in capillary blood may be due to greater exposure to air in capillary tubes, and this most likely explains the observed difference between venous and capillary ionized magnesium at actual pH.

Adult↗
PubMed2001

A two-hybrid system for transactivator bait proteins.

We describe a two-hybrid strategy for detection of interactions with transactivator proteins. This repressed transactivator (RTA) system employs the N-terminal repression domain of the yeast general repressor TUP1. TUP1-GAL80 fusion proteins, when coexpressed with GAL4, are shown to inhibit transcription of GAL4-dependent reporter genes. This effect requires the C-terminal 30 residues of GAL4, which are required for interaction with GAL80 in vitro. Furthermore, repression of GAL transcription by TUP1-GAL80 requires SRB10, demonstrating that the TUP1 repression domain, in the context of a two-hybrid interaction, functions by the same mechanism as endogenous TUP1. Using this strategy, we demonstrate interactions between the mammalian basic helix-loop-helix proteins MyoD and E12, and between c-Myc and Bin-1. We have also identified interacting clones from a TUP1-cDNA fusion expression library by using GAL4-VP16 as a bait fusion. These results demonstrate that RTA is generally applicable for identifying and characterizing interactions with transactivator proteins in vivo.

Animals↗
PubMed2001

Muscle satellite cells are multipotential stem cells that exhibit myogenic, osteogenic, and adipogenic differentiation.

Muscle satellite cells are believed to represent a committed stem cell population that is responsible for the postnatal growth and regeneration of skeletal muscle. However, the observation that cultured myoblasts differentiate into osteocytes or adipocytes following treatment with bone morphogenetic proteins (BMPs) or adipogenic inducers, respectively, suggests some degree of plasticity within the mesenchymal lineage. To further investigate this phenomenon, we explore the osteogenic and adipogenic potential of satellite cells isolated from adult mice. Our experiments clearly demonstrate that satellite cell-derived primary myoblasts, expressing myogenic markers such as MyoD, Myf5, Pax7 and desmin, differentiated only into osteocytes or adipocytes following treatment with BMPs or adipogenic inducers, respectively However, satellite cells on isolated muscle fibers cultured in Matrigel readily differentiated into myocytes as well as osteogenic and adipogenic lineages, whereas primary myoblasts did not. Satellite cell-derived primary myoblasts isolated from mice lacking the myogenic transcription factor MyoD (MyoD-/-) differentiate into myocytes poorly in vivo and in vitro (Megeney et al., Genes Dev. 1996; Sabourin et. al, J. Cell Biol., 1999). Therefore, we tested whether MyoD-/- primary myoblasts display increased plasticity relative to wild type cells. Unexpectedly, the osteogenic or adipogenic differentiation potential of MyoD-/- primary myoblasts did not increase compared to wild-type cells. Taken together, these results strongly suggest that muscle satellite cells possess multipotential mesenchymal stem cell activity and are capable of forming osteocytes and adipocytes as well as myocytes.

Adipocytes↗
PubMed2001

Uremic toxins modulate the spontaneous apoptotic cell death and essential functions of neutrophils.

Clearance of neutrophils via apoptosis from the site of infection is crucial for the coordinated resolution of inflammation. The balance between stimulating and attenuating as well as between pro- and anti-apoptotic factors is necessary for maintenance of an effective immune response without the harmful side effects of neutrophil action. This article describes the effect of glucose-modified serum proteins and of free immunoglobulin light chains (IgLCs) on neutrophil functions and apoptosis. Both groups of proteins are found at elevated levels in sera of uremic patients. Glucose-modified proteins increase both the chemotactic movement of neutrophils and the activation of glucose uptake. Spontaneous neutrophil apoptosis is increased in the presence of these modified serum proteins. On the other hand, the presence of free IgLCs, previously shown to diminish neutrophil chemotaxis and the activation of glucose uptake, increase the percentage of viable neutrophils by inhibiting spontaneous apoptotic cell death. We conclude that both glucose-modified proteins and free IgLCs can be considered to be uremic toxins and both contribute to the disturbed immune function in uremic patients. Their concentrations as well as the microenvironment in which they are acting seem to be important for their actual effects.

Apoptosis↗
PubMed2001

Whole blood ionized magnesium in neonatal acidosis and preterm infants: a prospective consecutive study.

UNLABELLED: The mineral magnesium is a crucial enzymatic cofactor in the cellular bioenergetic process and alternations in magnesium metabolism may be associated with neurological impairment in newborn infants. Therefore, ionized magnesium (IMg) was measured in 14 newborn infants with acidosis [umbilical arterial cord pH 7.00 +/- 0.06, Apgar score 8.3 +/- 1.6 after 5 min, gestational age (GA) 276 +/- 16 d] and 15 premature infants (umbilical arterial cord pH 7.31 +/- 0.07, GA 236 +/- 12 d). Nineteen healthy mature infants served as controls. Arterial umbilical cord samples were taken immediately after delivery and capillary blood samples were taken 2, 6, 12 and 24 h after delivery by heel stick. IMg was measured by NOVA 8. The results showed an increased umbilical cord blood IMg in infants with acidosis compared with both premature and normal infants (0.58 +/- 0.08 mmol l(-1) vs 0.51 +/- 0.03 mmol l(-1) and 0.49 +/- 0.03 mmol l(-1); p < 0.0001). In infants with acidosis IMg declined significantly 2 h after delivery to 0.49 +/- 0.05 mmol l(-1) (p < 0.0001) and did not show any further significant changes during the first day of life. In premature infants and controls IMg levels were constant during the observation period. CONCLUSION: These findings suggest that elevated IMg is associated with neonatal acidosis.

Acidosis↗
PubMed2000

Activation of fgf4 gene expression in the myotomes is regulated by myogenic bHLH factors and by sonic hedgehog.

The Fgf4 gene encodes an important signaling molecule which is expressed in specific developmental stages, including the inner cell mass of the blastocyst, the myotomes, and the limb bud apical ectodermal ridge (AER). Using a transgenic approach, we previously identified overlapping but distinct enhancer elements in the Fgf4 3' untranslated region necessary and sufficient for myotome and AER expression. Here we have investigated the hypothesis that Fgf4 is a target of myogenic bHLH factors. We show by mutational analysis that a conserved E box located in the Fgf4 myotome enhancer is required for Fgf4-lacZ expression in the myotomes. A DNA probe containing the E box binds MYF5, MYOD, and bHLH-like activities from nuclear extracts of differentiating C2-7 myoblast cells, and both MYF5 and MYOD can activate gene expression of reporter plasmids containing the E-box element. Analyses of Myf5 and MyoD knockout mice harboring Fgf4-lacZ transgenes show that Myf5 is required for Fgf4 expression in the myotomes, while MyoD is not, but MyoD can sustain Fgf4 expression in the ventral myotomes in the absence of Myf5. Sonic hedgehog (Shh) signaling has been shown to have an essential inductive function in the expression of Myf5 and MyoD in the epaxial myotomes, but not in the hypaxial myotomes. We show here that expression of an Fgf4-lacZ transgene in Shh-/- embryos is suppressed not only in the epaxial but also in the hypaxial myotomes, while it is maintained in the AER. This suggests that Shh mediates Fgf4 activation in the myotomes through mechanisms independent of its role in the activation of myogenic factors. Thus, a cascade of events, involving Shh and bHLH factors, is responsible for activating Fgf4 expression in the myotomes in a spatial- and temporal-specific manner.

3' Untranslated Regions↗
PubMed2000

Comparison of magnesium and methyldopa for the control of blood pressure in pregnancies complicated with hypertension.

OBJECTIVES: Although magnesium is now the drug of choice for the prevention of eclamptic seizures only few studies have evaluated whether magnesium may reduce blood pressure in pregnancies complicated with hypertension. METHODS: A total of 33 patients with pregnancy-induced hypertension were randomized to either magnesium or methyldopa treatment. Of these 16 received magnesium and 17 methyldopa. The treatment comprised a 48-hour magnesium infusion followed by oral magnesium tablets until 3 days after delivery or 250 mg methyldopa 4 times a day in a similar period. RESULTS: Patients treated with magnesium had 1 day after inclusion a statistically significantly lower systolic blood pressure compared to the level in the methyldopa group (138.1 +/- 11 vs. 147.6 +/- 11 mm Hg; p < 0.05), but no difference was observed in diastolic blood pressure (92.0 +/- 6.6 vs. 96.0 +/- 10.1 mm Hg; NS). From the 5th day of inclusion and until delivery both systolic and diastolic blood pressure were significantly lower in the magnesium group (p < 0.05). Including all blood pressure measurements in a single analysis showed that both systolic (138 +/- 13 vs. 148 +/- 15 mm Hg; p < 0.0001) and diastolic (92 +/- 10 vs. 94 +/- 10 mm Hg; p < 0.05) blood pressure were lower in the magnesium group compared to the methyldopa group. There was no difference between the two groups regarding gestational age at delivery, birth weight, Apgar scores and pH in umbilical cord blood. CONCLUSION: This preliminary study demonstrates that magnesium treatment lowers blood pressure in pregnancies complicated with hypertension. The effect is without any adverse effect on maternal and neonatal well-being.

Adult↗
PubMed1998

Lack of relationship between serum and gallbladder bile calcium in patients with gallstone disease.

BACKGROUND: Recent studies suggest that alternation in serum calcium influences the level of gallbladder bile ionized calcium (Ca2+). Theoretically, this could increase the risk of calcium precipitation in the gallbladder. METHODS: We therefore measured serum and gallbladder bile minerals in patients with gallstones (n = 27) and without (n = 10, controls). The serum samples were taken just prior to induction of anaesthesia and gallbladder bile was aspirated before any manipulation of the gallbladder. RESULTS: The active molality of Ca2+ in gallbladder bile was not statistically significant different between cases and controls (0.44 +/- 0.16 vs. 0.40 +/- 0.10 mmol/kg), whereas pH was significantly lower (6.94 +/- 0.31 vs. 7.36 +/- 0.28, p < 0.0001) and cholesterol higher (4.37 +/- 2.70 vs. 1.79 +/- 1.33 mmol/l; p < 0.01) in gallbladder bile obtained from cases. Serum Ca2+ at actual pH, magnesium and phosphate were significantly higher among cases than in controls. Gallbladder bile active molality of Ca2+ was significantly correlated with bile total calcium in both groups (r = 0.72; p < 0.001 and r = 0.91; p < 0.001, respectively). In controls only, we observed a positive relationship between serum Ca2+ at actual pH and the active molality of Ca2+ in bile (r = 0.61; p < 0.05). CONCLUSION: Our study demonstrates that Ca2+ in gallbladder bile does not differ between cases and controls. The lack of correlation between serum and gallbladder bile constituents in cases compared to controls suggests that changes in calcium equilibration between bile and serum in patients with gallstone disease might be of importance for the formation of gallstones.

Adult↗
PubMed1998

Isolation of modified ubiquitin as a neutrophil chemotaxis inhibitor from uremic patients.

Uremic toxins are factors that accumulate in the serum and peritoneal cavity of uremic patients. They are responsible for a variety of functional disturbances and also contribute to the increased risk of infection by interfering with essential functions of the unspecific immune response. From the peritoneal effluent of peritoneal dialysis (PD) patients, a peptide was isolated by applying three different chromatographic methods. This peptide inhibits the chemotactic movement of polymorphonuclear leukocytes (PMNL) in an in vitro assay in a concentration-dependent, nonreversible manner, and therefore belongs to the group of uremic toxins. Amino acid sequencing showed that the isolated peptide has the same amino terminal sequence as ubiquitin. The peptide also reacted with anti-ubiquitin antibodies in a Western blot experiment, but had a more acidic isoelectric point than ubiquitin. By using affinity chromatography, anti-ubiquitin antibody binding fractions were isolated from all PD and hemodialysis (HD) patients investigated. These fractions contained the same acidic band and also significantly inhibited PMNL chemotaxis. Ubiquitin per se had no effect on PMNL chemotaxis. Therefore, it is concluded that from PD and HD patients a modified form of ubiquitin was isolated, and this modification was responsible for its inhibitory effect.

Antibodies↗
PubMed1997

MyoD protein is differentially accumulated in fast and slow skeletal muscle fibres and required for normal fibre type balance in rodents.

MyoD is a muscle-specific transcription factor involved in commitment of cells to myogenesis. MyoD mRNA levels differ between fast and slow muscles, suggesting that MyoD may regulate aspects of fibre type. Here we show that detectable MyoD protein becomes restricted during development to the nuclei of the fastest classes of fibres in fast muscles. myoDm1 mice, in which the myoD gene has been disrupted, show subtle shifts in fibre type of fast muscles toward a slower character, suggesting that MyoD is involved in the maintenance of the fast IIB/IIX fibre type. In contrast, slow muscle shifts to a faster phenotype in myoDm1. Moreover, MD6.0-lacZ transgenic mice with the myoD promoter driving lacZ, show highest beta-galactosidase activity in the fastest fibres of fast muscles, but also express low levels in slow fibres of slow, but not fast, muscles, suggesting distinct regulation of gene expression in slow fibres of fast and slow muscles.

Age Factors↗
PubMed1997

Activation of plasma contact and coagulation systems and neutrophils in the active phase of ulcerative colitis.

We have shown that the contact (kallikrein-kinin) system is involved in the pathogenesis of experimental enterocolitis. We now investigate activation of the contact and coagulation pathways, platelets, and neutrophils in active and inactive ulcerative colitis patients as compared to normal controls. In active ulcerative colitis patients, a significant decrease of plasma prekallikrein, high molecular weight kininogen, and C1 inhibitor levels was observed as compared with controls, as well as prekallikrein activation on western blots. Significant elevation of prothrombin fragment (F1 + 2), which indicates thrombin generation, and elastase-alpha 1-antitrypsin complexes, reflecting neutrophil activation, were found in patients with active disease. Plasma beta-thromboglobulin, a marker of platelet activation, was elevated in both active and inactive disease and appears to be a feature of ulcerative colitis. Activation of contact and coagulation pathways, as well as neutrophils, may mediate inflammation in the active phase of ulcerative colitis.

Adult↗
PubMed1997

A peptide isolated from a patient on continuous ambulatory peritoneal dialysis has homology to ubiquitin and inhibits the chemotactic response of polymorphonuclear leukocytes.

Susceptibility to bacterial infections in the peritoneal cavity is a serious problem for peritoneal dialysis patients. Uremic toxins are among the causes of the diminished function of polymorphonuclear leuckocytes (PMNLs), cells of the local immune defense. We isolated from the peritoneal dialysis effluent of a uremic patient, a peptide that inhibits PMNL chemotaxis in a concentration-dependent manner. The amino terminus of this factor is identical to that of ubiquitin. The peptide shows the same size as ubiquitin on SDS-polyacrylamide gels, but has a more acidic isoelectric point than intact ubiquitin, which has no effect on PMNL chemotaxis. We conclude that we have isolated a modified form of ubiquitin and that this modification is responsible for its inhibiting effect on PMNL chemotaxis.

Chemotaxis, Leukocyte↗
PubMed1996

Inhibition of unstimulated exocrine pancreatic secretion by peptide YY in the rat.

Peptide YY is an ileocolonic peptide known to inhibit postprandial and cholecystokinin-induced pancreatic exocrine secretion. It has also been shown to increase intestinal water and electrolyte absorption. These findings implicate PYY as being potentially useful for controlling watery diarrhea. Although its inhibitory effect on stimulated pancreatic secretion has been well established, PYY effects on interdigestive, unstimulated pancreatic secretion is not known. This study was designed to evaluate the effect of PYY on basal pancreatic exocrine secretion in a conscious rat. Male Sprague-Dawley rats were prepared with catheters for internal biliary bypass, pancreatic juice collection, and intraduodenal reinfusion of pancreatic juice. Jugular and carotid catheters were inserted for drug infusions and blood sampling. After overnight recovery, fasting rats were infused over 6 hours with saline or PYY (400 or 800 pmol/kg/hr). Pancreatic juice was measured and sampled at 60-minute intervals for volume and its protein and bicarbonate content. The remainder was reinfused into the duodenum. Before and after the experiment, pancreatic juice was automatically reinfused by a photocell-controlled peristaltic pump system. Intraductal pancreatic secretion was not affected by PYY at a dose of 400 pmol/kg/hr. PYY at a dose of 800 pmol/kg/hr significantly reduced the volume of pancreatic secretion and its protein and bicarbonate content. Pancreatic secretory response normalized within 24 hours. In conclusion, unstimulated pancreatic exocrine secretion can be inhibited by exogenous PYY in the rat.

Amylases↗