Biomedical subjects

M Paul

Publications and source records attributed to M Paul.

At least 127 records · Page 7Linked to original sources

PubMed2001

Quantitative analysis of estrogen receptor mRNA in human endometrium throughout the menstrual cycle using a real-time reverse transcription-polymerase chain reaction assay.

We conducted a quantitative analysis of ERalpha and ERbeta mRNA expression in normal human endometrium throughout the menstrual cycle in regular menstruating premenopausal women, taking advantage of this real-time PCR assay. Endometrial dating was determined from the histology of the endometrium and classified into: proliferative endometrium and secretory endometrium. Both ERalpha and ERbeta mRNA expression were detected in all endometrial samples at both proliferative and secretion phase. However ERalpha mRNA expression level was higher than that of ERbeta specially during proliferative phase. These results suggest that estrogenic effects occur predominantly through ERalpha than ERbeta.

Adult↗

PubMed2001

Quantitative analysis of estrogen receptor-alpha and -beta and exon 5 splicing variant mRNA in endometrial hyperplasia in perimenopausal women.

We used real-time reverse transcription-polymerase chain reaction (QRT-PCR) to detect wild-type ERalpha and ERbeta and their isoforms as well as exon 5 splicing variant mRNA ERalpha in various types of endometrial hyperplasia in perimenopausal women. Our data suggest that the exon 2 and 7 deletion ERalpha mRNA isoforms are present in endometrial tissue undergoing various hyperplastic states. Wild type ERbeta mRNA and their isoforms 2, 4, 5, 6 were observed in each type of assessed endometrial specimens, and ERalpha/delta5 was found only in hyperplasia complex group.

Adult↗

PubMed2001

Expression of telomerase genes as potential marker of neoplastic changes.

We conducted a quantitative analysis of TERT, TP1 and hTR mRNA expression in various types of endometrial hyperplasia in perimenopausal women, taking advantage of the real-time PCR assay. All women underwent hysterectomy for gynecological reasons. Endometrial dating was determined from the patomorphology of the endometrium and classified into endometrial hyperplasia: simplex, complex and atypica. Our data suggest that only hTR was observed in each normal and hyperplastic endometrium specimens, suggesting that this factor constitutively expressed in endometrium. The results obtained indicate that the expression activity of the TERT subunit changes but not significantly, depending on the stage of development of the hyperplasia.

Adult↗

PubMed2001

[Histone H3 gene expression level as markers of hyperplasia simplex of endometrium].

SUBJECT: The excessive proliferative activity of endometrial cells drives to hyperplasia, via states: simplex hyperplasia, complex and atypical hyperplasia, and finally preneoplastic state may arise. New molecular markers and their ability to differentiate physiological and pathological states are described. DESIGN: The aim of this study was to evaluate the usefulness of histone H3 gene expression level as a marker of hyperplasia of endometrium. MATERIAL AND METHODS: The level of H3 mRNA was estimated using RT-QPCR method in proliferative phase (n = 5) and endometrial hyperplasia simplex (n = 8). Differences in expression level of H3, were evaluated by Student's t-test (t-test for independent samples). RESULTS: In our experiments the average mRNA H3 expression was significantly higher(p < 0.05, p = 0.03) in case of hyperplasia simplex in comparison to H3 expression in proliferative state of endometrium. CONCLUSION: The results confirm advantage of estimation of H3 mRNA level as a marker of cell proliferation in endometrium.

Adult↗

PubMed2001

[Quantitative (RT-QPCR) analysis of telomerase subunit in normal endometrial tissues].

Telomerase is a specialized ribonucleoprotein polymerase that elongates telomeres. To clarify the molecular mechanisms through which telomerase is activated in normal endometrium, we examined the expression profiles of each telomerase subunit in this tissues. A total of 22 normal human endometrium in various menstrual phases were examined for the expression of each telomerase subunit (hTERT, hTR, TP-1) using RT-QPCR. The hTERT as well as TP-1 subunit had higher expression levels in proliferative than secretory phase endometrium. Expression levels of hTR did not change during menstrual cycle. Our data showed the strong correlation between the level of expression of telomerase in human endometrium and phase of menstrual cycle.

Adult↗

PubMed2001

[Clinical value of Echinococcus granulosus--specific immunoglobulin G antibody avidity in liver cystic echinococcosis].

Role of E. granulosus-specific IgG antibody avidity in evaluation of a natural history of the parasite cysts in the liver, duration of infection and immunogenic cysts activity was studied. Thirty-one patients with liver cysts suspected of echinococcosis were examined; E. granulosus infection was finally confirmed by a fine needle aspiration biopsy or surgery in 29 cases (93.5%) and two non-parasitic simple cysts in the liver were diagnosed. E. granulosus-specific IgG antibody was found in 21 patients (67.7%). High IgG avidity values were observed in 14 patients with liver cysts in a degeneration stage confirmed by imaging techniques. Low IgG avidity values were mostly detected in children with hypoechogenic echinococcal cysts being in a recent stage of infection. Determination of anti-E. granulosus immunoglobulin G antibody avidity is a very usefull diagnostic tool for a determination of parasitic cysts activity and their developmental age.

Adolescent↗

PubMed2001

[Analysis of the local synthesis of Toxoplasma gondii-specific immunoglobulins in the anterior eye chamber fluid. Report of two cases].

We reported two cases strongly suspected of ocular toxoplasmosis, in which a puncture of anterior eye chamber was performed for a final verification of clinical diagnosis. In both patients, fresh focal lesions of retinochoroiditis associated with old pigmented retinal scars were diagnosed. The 62-year-old women had a serological evidence of recently acquired T. gondii infection with an increasing IgG titre of a low avidity and a presence of specific IgM and IgA antibodies. In the 13-year-old girl, an immunological profile of the chronic infection was shown, confirmed by a high IgG avidity value. In the patient with a clinical picture of recurrent congenital toxoplasmosis, intraocular production of T. gondii-specific IgG was found in anterior eye chamber. The analysis of the specific antibodies synthesis in ocular fluid by the Western blot seems to be a valuable immunodiagnostic method for a final diagnosis of ocular toxoplasmosis.

Adolescent↗

PubMed2001

[Evaluation of the postnatal treatment efficacy in congenital toxoplasmosis identified by the newborn screening programme].

The effectiveness of neonatal screening for anti-Toxoplasma IgM or IgA and IgM specific antibodies followed by an intensive anti-parasitic therapy for a prevention of clinical and immunological reactivations of congenital infection was studied. Thirty-five congenitally infected infants were included into clinical and serological follow-up. The children were mostly asymptomatic at birth or they expressed some non-specific reversible clinical abnormalities in neonatal period. Clinically overt toxoplasmosis occurred in 10 patients, including one infant with a severe form; 2 children had co-existing CMV infections. During the follow-up period, no clinical relapses were reported. Asymptomatic immunological rebounds of IgG or of IgG and IgA specific antibodies were observed in 16 patients. Anti-parasitic treatment initiated soon after birth seems to be promising in a prevention of early clinical sequelae of congenital T. gondii infection.

Animals↗

PubMed2000

Cardiac endothelin system impairs left ventricular function in renin-dependent hypertension via decreased sarcoplasmic reticulum Ca(2+) uptake.

BACKGROUND: We evaluated the role of the cardiac endothelin (ET) system in compensated hypertensive left ventricular (LV) hypertrophy (LVH) and after the transition toward LV dysfunction. METHODS AND RESULTS: Hypertensive transgenic rats overexpressing the Ren2 gene (Ren2 rats) were investigated between the ages of 10 and 30 weeks (Ren2-10 and Ren2-30 groups, respectively) and compared with age-matched normotensive Sprague-Dawley (SD) rats (SD-10 and SD-30 groups, respectively). Systolic blood pressure and LV weight were elevated in both Ren2 groups compared with their age-matched SD control groups (P:<0.0001). In Ren2-30 rats, LV end-diastolic pressure increased and -dP/dt(max) decreased compared with the values in SD-30 and Ren2-10 rats (P:<0.05). This was paralleled by an activation of LV mRNA expression of preproET-1 and ET-converting enzyme-1 and ET subtype A (ETA) receptor binding in Ren2-30 compared with Ren2-10 rats (P:<0.001). Cardiac fibrosis was increased and sarcoplasmic reticulum (SR) Ca(2+) reuptake was reduced in Ren2-30 compared with SD-30 and Ren2-10 rats (P:<0.05). Treatment of Ren2 rats with the selective ETA receptor antagonist Lu135252 between 10 and 30 weeks of age did not lower systolic blood pressure, heart weight, or cardiac fibrosis but completely prevented the deterioration of LV end-diastolic pressure and abolished alterations in -dP/dt(max) and SR Ca(2+) reuptake compared with no treatment in Ren2-30 and SD-30 rats (P:<0.05). CONCLUSIONS: Activation of the cardiac ET system accounts at least in part for the LV dysfunction that gradually develops in LVH. The protective effect of ETA antagonism can be attributed to the improvement of diastolic LV function that is due to normalization of impaired SR Ca(2+) uptake.

Animals↗

PubMed2000

Expression and function of endothelial Ca(2+)-activated K(+) channels in human mesenteric artery: A single-cell reverse transcriptase-polymerase chain reaction and electrophysiological study in situ.

Ca(2+)-activated K(+) (K(Ca)) channels have been suggested to play a role in the control of endothelial functions such as regulation of vascular tone and cell proliferation. We established a method for single-cell reverse transcriptase-polymerase chain reaction analysis in combination with the patch-clamp technique to characterize K(Ca) channel expression and function in single endothelial cells (ECs) within the endothelial monolayer of intact human mesenteric arteries (MAs) and in disease states. We tested whether endothelial K(Ca) channel expression and function are altered in MAs obtained from patients with colonic adenocarcinoma (CA) compared with those in MAs from non-cancer patients with inactive diverticulitis. Expression of the intermediate-conductance K(Ca) channel (hIK1) was detected in non-cancer and CA patients. In whole-cell patch-clamp measurements, only ECs expressing hIK1 exhibited corresponding K(Ca) currents, whereas respective K(Ca) currents were missing in hIK1-negative ECs. This heterogeneity of hIK1 expression patterns is indicative of a specialized subset of ECs within the endothelial monolayer. In CA patients, compared with non-cancer patients, a 2.5-fold increase in hIK1-expressing ECs per MA was observed (P:<0.05). However, K(Ca) current densities in hIK1-expressing ECs of both groups were similar. In addition to hIK1, expression of the large-conductance K(Ca) channel (hSlo) was detected in single ECs from CA patients. The increased K(Ca) channel expression in CA patients resulted in a 2. 7-fold increase of bradykinin-induced endothelial hyperpolarization compared with controls (P:<0.05). This increased expression and function of K(Ca) channels might indicate an altered functional state of the endothelium in cancer patients and could play a role in tumor angiogenesis.

Adenocarcinoma↗

PubMed2000

The 44Ti(alpha,p) reaction and its implication on the 44Ti yield in supernovae

Cross sections for the 44Ti(alpha,p)47V reaction which significantly affects the yield of 44Ti in supernovae were measured in the energy range 5.7 MeV</=E(c.m.)</=9 MeV, using a beam of radioactive 44Ti. The cross sections and the deduced astrophysical reaction rates are larger than the results from theoretical calculations by about a factor of 2. The implications of this increase in the reaction rate for the search of supernovae using space-based gamma detectors are discussed.

Journal Article↗

PubMed2000

Characterization of the c-specific promoter of the gene encoding human endothelin-converting enzyme-1 (ECE-1).

Human ECE-1 is expressed in four isoforms with different tissue distribution and its mRNA and protein levels are altered under certain pathophysiological conditions. To investigate the transcriptional regulation of ECE-1, we studied the regulatory region of ECE-1c, the major ECE-1 isoform. A genomic clone comprising the complete human ECE-1 gene including the putative ECE-1c-specific promoter was obtained. Up to 968 bp upstream of the putative c-specific translation initiation start codon and several serial deletion mutants were subcloned into a reporter vector and transfected into endothelial (BAEC, EA.hy926, ECV304) and epithelial (MDA MB435S, MCF7) cells, showing very strong promoter activity in comparison to the SV40 promoter and to the previously described ECE-1a and 1b promoters. Transfection of serial deletion mutants indicated two positive regulatory regions within the promoter (-142/-240 and -240/490) likely involved in binding GATA and ETS transcription factors. RNase protection assay (RPA) and 5'-RACE revealed multiple transcriptional start sites located at about -110, -140 and -350 bp. Site-directed mutagenesis demonstrated a crucial role for the E2F cis-element for basal ECE-1c promoter activity. Additionally, we found a correlation between isoform-specific ECE-1 mRNA levels and corresponding ECE-1a, 1b, 1c promoter activities.

Aspartic Acid Endopeptidases↗

PubMed2000

Oxidative stress increases synthesis of big endothelin-1 by activation of the endothelin-1 promoter.

Modulation of the biosynthesis of the vasoconstrictor peptide endothelin-1 by oxygen-derived free radicals generated by xanthine oxidase or hydrogen peroxide was studied in cultured endothelial cells. Endothelin-1 metabolism was investigated at the level of endothelin-1 promoter, preproendothelin-1 mRNA and intracellular big endothelin-1. Endothelin-1 mRNA, as characterized by Northern blotting, was increased both time- and dose-dependently by xanthine oxidase to up to 500% above baseline. Analysis of endothelin-1 promoter activity using a construct containing 1329 bp of the endothelin-1 promoter revealed that promoter activity was increased up to eight-fold by incubation with xanthine oxidase. Specificity was ascertained by co-incubation with superoxide dismutase and catalase leading to inhibition of the effect of xanthine oxidase. A significant contribution of nitric oxide was ruled out, since NOS III-mRNA transcription remained unchanged and l -NAME did not significantly alter endothelin-1 promoter activity. Synthesis of intracellular big endothelin-1 protein was increased dose-dependently by xanthine oxidase. Our results indicate that oxidative stress leads to increased endothelial synthesis of big endothelin-1, which is a previously unknown mechanism and may help to understand the detrimental association of increased oxidative stress and elevated endothelin-1 levels in pathophysiological conditions promoting atherosclerosis.

Animals↗

PubMed2000

Transcriptional control of deformation-induced preproendothelin-1 gene expression in endothelial cells.

Deformation-induced synthesis of endothelin-1 (ET-1) in endothelial cells exposed to high blood pressure may play an important role in vein graft disease and in restenosis following percutaneous transluminal angioplasty. Effective inhibitors of preproendothelin ET-1 (ppET-1) processing to ET-1 are not available, and blockade of ppET-1 expression may therefore emerge as an alternative therapeutic approach. To evaluate this, we investigated deformation-sensitive transcription factors controlling ppET-1 expression in both native (rabbit carotid artery and jugular vein) and cultured endothelial cells (EC; porcine aorta and human umbilical vein). Deformation of both native and cultured endothelial cells for 6 h resulted in a marked increase in ET-1 synthesis which was preceded by a transient (30-60 min) activation of transcription factors activator protein-1 (AP-1) and CCAAT/enhancer-binding protein (C/EBP) beta and/or delta. A decoy oligodeoxynucleotide directed against AP-1 inhibited deformation-induced ppET-1 expression in the rabbit jugular vein as well as in porcine aorta EC and human umbilical vein EC but not in the rabbit carotid artery. Subsequent reporter gene analyses with different rat ppET-1 promoter-luciferase constructs transiently transfected into porcine aorta EC identified a single AP-1 binding site at -110 to -100 bp as the primary response element for deformation-induced ppET-1 expression. Moreover, a C/EBP-specific decoy oligodeoxynucleotide abolished ppET-1 expression in the endothelium of the rabbit carotid artery, but not in the jugular vein where basal ET-1 synthesis was greatly enhanced instead. These findings suggest that the key transcription factors controlling deformation-induced ppET-1 expression in endothelial cells are blood vessel rather than species-specific. In humans, adjunct treatment with an AP-1-specific decoy oligodeoxynucleotide may prove be an interesting gene therapeutic option for the above cardiovascular interventions.

Animals↗

PubMed2000

[The renin-angiotensin system as the basic principle for hypertension and coronary heart diseases--role of genetic factors].

Since the discovery of renin by Tigerstedt and Bergmann, the renin angiotensin system (RAS) has been recognized as an important modulator of blood pressure and volume homeostasis. Based on these functions a pathophysiological role of the RAS in the pathogenesis of hypertension and other cardiovascular disorders has been postulated. The therapeutic benefit of RAS inhibition by angiotensin converting enzyme (ACE) inhibitors and angiotensin II (ANG II) antagonists in these conditions has been shown. It remains unclear, however, whether the changes in RAS activity associated with cardiovascular disease are primary or secondary factors. It is well known that hypertension and hypertensive end-organ disease is influenced by genetic factors. Gene polymorphisms for virtually all components of the RAS have been described and investigated in clinical studies. It remains to be determined, however, how relevant these findings are for disease etiology. This review, therefore, will attempt to discuss the causal implications of these genetic studies for cardiovascular disease. The role of angiotensinogen and ACE for hypertension, coronary artery disease and other cardiovascular disorders is discussed in this context in an exemplary fashion.

Angiotensinogen↗

PubMed2000

Differential lusitropic responsiveness to beta-adrenergic stimulation in rat atrial and ventricular cardiac myocytes.

Cardiac myocyte relaxation is brought about mainly through Ca2+ uptake into the sarcoplasmic reticulum (SR) by a Ca2+-ATPase isoform, SERCA2a. Its activity is modulated by another protein, phospholamban (PLB). The levels of both proteins differ in some mammals between atrial and ventricular myocardium and this may lead to differences in relaxation, especially under stimulatory conditions. At a concentration of 100 nM, the beta-adrenergic agonist isoprenaline (ISO) accelerates the relaxation of rat papillary muscle more than that of the left atria (16.4 versus 4.0% hastening of time to 50% relaxation, respectively). Ventricular myocytes were 24.7% quicker in reaching 50% of their diastolic length after contraction when treated with ISO compared to atrial myocytes, which were only 3.6% faster. Ca2+ fluorescence transients were also abbreviated in ventricular compared to atrial myocytes exposed to ISO (41.9 versus 25.2% hastening of time to 50% peak Ca2+ respectively). Ca2+ uptake into ventricular SR vesicles was increased by 13% in the presence of protein kinase A while that into atrial SR vesicles remained unaffected. Western blotting analysis revealed 23% less SERCA2a protein, but 76% more PLB in ventricular compared to atrial tissue. We conclude that the distinct levels of SERCA2a and PLB in ventricular and atrial myocardium are responsible for the differential modulation of the relaxation process arising from beta-adrenergic stimulation in single rat atrial and ventricular myocytes.

Adrenergic beta-Agonists↗

PubMed2000

Therapeutic evaluation of free and liposome-encapsulated atovaquone in the treatment of murine leishmaniasis.

The use of drug delivery systems may reduce the toxicity and improve the activity of anti-leishmanial compounds. The activity of atovaquone (ATV)-loaded liposomes was compared by determination of median effective doses (ED(25) and ED(50)), with that of free ATV in a murine model of visceral leishmaniasis induced by Leishmania infantum. On day 0, mice were infected intravenously with 4.10(7) promastigotes and treated via the tail vein on days 15, 17 and 19 by free drug in a DMSO/cremophor/water solution (0.2 to 1.6 mg/kg body weight) or by liposomal drug (0.04 to 0.32 mg/kg body weight). Mice were killed and livers and spleens were removed and weighed on day 21 p.i. and liver parasite burdens evaluated using the Stauber method. Effective doses were determined using the Hill representation relating the percentage of parasite suppression to the dose. Liposomal ATV was significantly more effective than the free drug in reducing liver parasites (61.6% of parasite suppression at a dose of 0.32 mg/kg vs 34.9% at a dose of 1.6mg/kg). Liposomal ATV was 23 times more active than the free drug (ED(25) value=0. 02+/-0.01 mg/kg vs 0.46+/-0.15 mg/kg for free drug). It was not possible to obtain the ED(50) for free ATV because the dose-response curve reached a plateau around 33% of parasite suppression. Conversely, the ED(50) for liposomal ATV was 0.17+/-0.05 mg/kg. 100% efficacy of bound ATV could be obtained with a concentration of 1. 77+/-0.35 mg/kg. A significant decrease in spleen weights was also observed reflecting a leishmanicidal activity of ATV. These results suggest that liposome loaded ATV is more efficacious than the free drug against Leishmania infantum in this murine model.

Animals↗

PubMed2000

Influence of sustained mechanical stress on Egr-1 mRNA expression in cultured human endothelial cells.

Restenosis after initially successful balloon angioplasty of coronary artery stenosis remains a major problem in clinical cardiology. Previous studies have identified pathogenetic factors which trigger cell proliferation and vascular remodeling ultimately leading to restenosis. Since there is evidence that endothelial cells adjacent to the angioplasty wound area synthesize factors which may initiate this process, we investigated the effects of mechanical stimulation on endothelial gene expression in vitro and focussed on the influence of sustained mechanical stress on expression of immediate early genes which have previously been shown to be induced in the vascular wall in vivo. Primary cultured human umbilical vein endothelial cells (HUVEC) and the human endothelial cell line EA.hy 926 were plated on collagen-coated silicone membranes and subjected to constant longitudinal stress of approximately 20% for 10 min to 6 h. Total RNA was isolated and the expression of the immediate early genes c-Fos and Egr-1 was studied by Northern blot analysis. We found a rapid upregulation c-Fos and Egr-1 mRNA which started at 10 min and reached its maxima at 30 min. HUVEC lost most of their stretch response after the third passage whereas immediate early gene expression was constantly in EA.hy 926 cells. Using specific inhibitors we investigated the contribution of several signal transduction pathways to stretch-activated Egr-1 mRNA expression. We found significant suppression of stretch-induced Egr-1 mRNA expression by protein kinase C (PKC) inhibition (p < 0.05) and by calcium depletion (EA.hy 926, p < 0.05; HUVEC, p = 0.063). No effect on stretch-activated Egr-1 mRNA expression was detected by inhibition of protein kinase A, blockade of stretch-activated cation channels or inhibition of microtubule synthesis. We conclude that sustained mechanical strain induces Egr-1 mRNA expression by PKC- and calcium-dependent mechanisms.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗