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A Stella

Publications and source records attributed to A Stella.

At least 19 recordsLinked to original sources
PubMed2000

Angiotensin II increases calponin expression in cultured rat vascular smooth muscle cells.

Angiotensin II (Ang II) action on vascular smooth muscle cells is not limited to contraction, but includes long term effects such as hypertrophy and hyperplasia. This implies a complex pattern of gene modulation, which remains largely unknown. We used the mRNA differential display method to screen rat aortic smooth muscle cells cultured with or without Ang II. We demonstrated that Ang II induces the expression of calponin, a 34-kD protein, which has been shown to regulate smooth muscle cell contraction and to be a marker of smooth muscle cell differentiation. We demonstrated this induction both at gene and protein level in vascular smooth muscle cells. Calponin mRNA was dose-dependently induced by Ang II, with an effect still evident at 5 x 10(-9)M, and it did not require active protein synthesis, since cycloheximide treatment did not suppress this induction. Calponin gene expression was maximal at 3 h, while protein expression was maximal at 8 h. Calponin expression was completely abolished by the AT1 receptor antagonist, losartan, at 1 x 10(-6)M. Our data demonstrate that Ang II increases calponin gene expression and protein level in rat aortic smooth muscle cells in vitro.

Analysis of Variance↗
PubMed2000

Pivotal role of the RB family proteins in in vitro thyroid cell transformation.

Rat thyroid differentiated cells (PC Cl 3) are an excellent model system with which to study the interaction between differentiation and cell transformation. We previously demonstrated that PC Cl 3 cells expressing the adenovirus E1A gene no longer depend on thyrotropin for growth and do not express thyroid differentiation markers. Here we show that an E1A mutant unable to bind the RB protein failed to transform the PC Cl 3 cells. Conversely, mutations in the E1A p300 interacting region did not affect its transforming ability. The pivotal role of RB family proteins in the thyroid cell transformation is supported by the thyrotropin independence induced by the E7 gene of human papilloma virus type 16, but not by a mutated form in the RB-binding region.

Adenovirus E1A Proteins↗
PubMed2000

Oxytocin receptors in human adenocarcinomas of the endometrium: presence and biological significance.

Oxytocin receptors (OTRs) are expressed in endometrial cells and oxytocin (OT) participates in endometrial functions. In cancers derived from other OT target tissues, such as breast and neural tissues, the expression of OTRs and the antiproliferative effect of OT on cancer cells has been previously observed. This study was therefore designed to search for OTR expression and the OT effect in endometrial carcinomas. To demonstrate the presence and the location of OTRs and OTR mRNA immunocytochemical, reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH) procedures were employed in a series of human adenocarcinomas of the endometrium. Using an anti-OTR monoclonal antibody (IF3), OTRs were demonstrated in the large majority of endometrial carcinomas (82%), with a pattern of positivity varying from diffuse to focal, according to tumour differentiation. The OTR gene was demonstrated in 78% of the cases by RT-PCR and its presence was confirmed in selected cases by ISH. Moreover, in a human endometrial carcinoma cell line (COLO 684) OTR was demonstrated by immunofluorescence and RT-PCR and it was observed that OT treatment (10(-11)-10(-7) M) significantly inhibited cell proliferation. Neither toxic effects nor apoptosis were induced by OT treatment. The addition of an inhibitor of protein kinase A (PKA) to the culture medium abolished the antiproliferative effect of OT, suggesting that cAMP via PKA could be the intracellular mediator of the OT effect, as previously observed in breast and neural tumours. In conclusion, this study presents evidence of OTR expression in human endometrial carcinomas and of an OT antiproliferative effect on human endometrial cancer cells in vitro. It is further suggested that OT and OTR may be involved in the regulation of endometrial cells, not only in physiological conditions but also in a neoplastic context.

Adenocarcinoma↗
PubMed2000

Effects of adenosine receptor agonists on efferent renal nerve activity in anesthetized rats.

The aim of this study was to investigate the effects of A1 and A2 adenosine-receptor activation on the sympathetic nervous system. The effects on efferent renal nerve activity of selective A1 (CCPA; 2-chloro-N-6-cyclopentyladenosine) and A2 (2HE-NECA; 2-hexynyl-5'-N-ethylcarboxamidoadenosine) adenosine-receptor agonists were studied in anesthetized rats either with intact baroreflexes (intact rats) or with bilateral sinoaortic denervation and vagotomy (denervated rats). After a control period of 5 min, A1 or A2 agonist or vehicle were intravenously infused for 8 min in separate groups of intact or denervated rats, in which arterial pressure and heart rate were continuously recorded. CCPA (5.0 microg/kg/min) and 2HE-NECA (0.7 microg/kg/min) were selected to obtain comparable blood pressure changes over the period of observation. Arterial pressure significantly and equally decreased during the A1 (-41 +/- 8%), and A2 (-35 +/- 5%) agonist administration. Heart rate significantly decreased during A1 agonist infusion, but it did not change during A2 agonist administration. Bilateral sinoaortic denervation and vagotomy did not modify the hemodynamic responses to both drugs. The A1 and A2 administration caused a large and significant increase in efferent renal nerve activity (+66 +/- 22% and +76 +/- 15%, respectively), and this effect was entirely abolished in denervated rats. A linear relation with a significant negative slope between changes in arterial pressure and changes in neural discharge was observed for each treatment. The comparison of the regression slopes showed that the reflex increase of efferent sympathetic activity caused by the administration of both agonists was significantly smaller than the increment induced by equipotent hypotensive dose of sodium nitroprusside (10 microg/kg). These data show that the selective activation of A1 and A2 receptors elicits a reflex increase in efferent renal nerve activity. This neural activation is smaller as compared with the effect of equihypotensive doses of sodium nitroprusside, thus indicating a blunting effect of both adenosine agonists on baroreceptor sensitivity.

Adenosine↗
PubMed2000

Rat protein tyrosine phosphatase eta suppresses the neoplastic phenotype of retrovirally transformed thyroid cells through the stabilization of p27(Kip1).

The r-PTPeta gene encodes a rat receptor-type protein tyrosine phosphatase whose expression is negatively regulated by neoplastic cell transformation. Here we first demonstrate a dramatic reduction in DEP-1/HPTPeta (the human homolog of r-PTPeta) expression in a panel of human thyroid carcinomas. Subsequently, we show that the reexpression of the r-PTPeta gene in highly malignant rat thyroid cells transformed by retroviruses carrying the v-mos and v-ras-Ki oncogenes suppresses their malignant phenotype. Cell cycle analysis demonstrated that r-PTPeta caused G(1) growth arrest and increased the cyclin-dependent kinase inhibitor p27(Kip1) protein level by reducing the proteasome-dependent degradation rate. We propose that the r-PTPeta tumor suppressor activity is mediated by p27(Kip1) protein stabilization, because suppression of p27(Kip1) protein synthesis using p27-specific antisense oligonucleotides blocked the growth-inhibitory effect induced by r-PTPeta. Furthermore, we provide evidence that in v-mos- or v-ras-Ki-transformed thyroid cells, the p27(Kip1) protein level was regulated by the mitogen-activated protein (MAP) kinase pathway and that r-PTPeta regulated p27(Kip1) stability by preventing v-mos- or v-ras-Ki-induced MAP kinase activation.

Animals↗
PubMed2000

The highly malignant phenotype of anaplastic thyroid carcinoma cell lines is recessive.

OBJECTIVE: The aim of our studies was to determine whether the phenotype of the anaplastic thyroid carcinomas is dominant or recessive. In fact, it is hypothesized, on the basis of epidemiological and pathological data, that undifferentiated thyroid carcinomas are derived from differentiated tumours through a mechanism of tumour progression. DESIGN: Cell hybrids have been generated by cell fusion of anaplastic thyroid carcinoma cell lines, which show a highly malignant phenotype, to cell lines deriving from differentiated thyroid carcinoma, which show a non-tumorigenic or a poorly tumorigenic phenotype. All of the parental cell lines showed impaired p53 gene function. RESULTS: The cell hybrids contained alleles from the parental cell lines. All of the cell hybrids showed a lower growth rate compared with the parental undifferentiated carcinoma cell lines and were unable to grow in soft agar and to induce tumours after injection into athymic mice. CONCLUSION: Taken together, these findings suggest that the highly malignant phenotype of the anaplastic thyroid carcinoma is achieved by the impairment of gene functions that negatively regulate cell growth, rather than by the activation of dominant oncogenes.

Animals↗
PubMed2000

Short-term analysis of the relationship between blood pressure and urinary sodium excretion in normotensive subjects.

The aim of this study was to investigate whether, in the short term, physiological blood pressure changes are coupled with changes in urinary sodium excretion in normotensive subjects, maintained at fixed sodium intake and under controlled postural and behavioural conditions. Twelve normotensive subjects were recruited. For each subject, seven urine samples were collected at fixed time intervals during an overall 26 h period: late afternoon (16.00-20.00 hours), evening (20.00-24.00 hours), night (24.00-06.00 hours), quiet wakefulness (06.00-09.00 hours), morning (09.00-12.00 hours), post-prandial (12.00-15.00 hours) and afternoon (15.00-18.00 hours). Blood pressure was monitored by an ambulatory blood pressure device during the whole 26 h period. Each urine sample was used to measure urinary sodium excretion and glomerular filtration rate (creatinine clearance). Blood pressure, heart rate, urinary sodium excretion and glomerular filtration rate recorded in the daytime were higher than those measured during the night-time. A significant positive correlation between mean blood pressure and urinary sodium excretion was found during the night, over the whole 26 h period, and during two subperiods of the daytime: quiet wakefulness and the post-prandial period. The coefficient of the pressure-natriuresis curve was significantly decreased by postural changes. We conclude that, in normotensive subjects, blood pressure and urinary sodium excretion are coupled in the short term. The assumption of an upright posture can mask this relationship, presumably by activating neurohumoral factors.

Adult↗
PubMed2000

Omphalocele and umbilical cord cyst. Prenatal diagnosis.

We present a case of intrauterine fetal death at 32 week's gestation with omphalocele, umbilical cord allantoic cyst and polyhydramnios. Ultrasound diagnosis of anomalies was performed at 23 weeks of gestation. Fetal karyotype was normal: 46 XX. This association has been found to have a high rate of chromosomal abnormalities, especially trisomy 18. It's difficult to explain the reason why intrauterine fetal death has happened; one possible hypothesis is that the cord cyst, compressing umbilical vessels, have caused intrauterine vascular compromise of blood flow.

Adult↗
PubMed1999

Bioactive IL-18 expression is up-regulated in Crohn's disease.

An imbalance of immunoregulatory factors is believed to contribute to uncontrolled mucosal Th1 cell activation in Crohn's disease (CD). IL-18, a macrophage-like cell-derived cytokine, is involved in Th1 clone development, and IFN-gamma production. Therefore, IL-18 expression was investigated in CD. Whole mucosal intestinal tissue and lamina propria mononuclear cells (LPMC) of 12 CD and 9 ulcerative colitis (UC) patients and 15 non-inflammatory bowel disease (IBD) controls were tested for IL-18 by semiquantitative RT-PCR and Western blot analysis. Transcripts for IL-18 were found in all samples tested. However, increased IL-18 mRNA accumulation was detected in both mucosal and LPMC samples from CD in comparison to UC and controls. In CD, transcripts for IL-18 were more abundant in the mucosal samples taken from involved areas. An 18-kDa band consistent with mature IL-18 was predominantly found in CD mucosal samples. In mucosal samples from non-IBD controls, IL-18 was present as a 24-kDa polypeptide. Consistently, active IL-1beta-converting enzyme (ICE) subunit (p20) was expressed in samples from either CD or UC, whereas, in colonic mucosa from non-IBD controls, ICE was synthesized as precursor (p45) only. To confirm that IL-18 produced in CD tissue was functionally active, CD LPMC were treated with a specific IL-18 antisense oligonucleotide. In these cultures, IL-18 down-regulation was accompanied by a decrease in IFN-gamma expression. In aggregate, our data indicate that IL-18 up-regulation is a feature of CD and suggest that IL-18 may contribute to the local immunoinflammatory response in CD.

Caspase 1↗
PubMed1999

Comparison of clinical and demographic features between affected pairs of Italian multiple sclerosis multiplex families; relation to tumour necrosis factor genomic polymorphisms.

We conducted a comparative analysis of clinical and demographic findings between pairs of relatives (36 sibling and 9 parent/child), concordant for Multiple Sclerosis (MS), from 40 MS Italian Multiplex families. A genetic TNF (alpha and beta) loci typing in 51 affected and 69 healthy relatives belonging to 25 of these families was also performed. The sib pairs resulted significantly concordant for age at onset (r=0.414, P<0.013), Progression Index (r=0.34, P<0.05) and sensory symptoms at onset (k=0.37), and significantly not concordant for sex (k=-0.37), whereas no concordance was found for year at onset and disease course. The only significant result in the small group of parent/child pairs was that parents developed MS at an age of 18.74 years significantly (P=0.020) greater than their children. Genomic analysis identified 13 variants of TNF-a alleles, 7 of TNF-b, 6 of TNF-d and 3 of TNF-e. No differences in the frequencies of the various TNF alleles were observed between affected and healthy relatives. The two-point lod-score analysis of the TNF locus showed not significant or negative results for the TNFalpha loci and slightly positive results (Zmax=0.4 at theta=0.2 cM) for the TNFbeta-b locus in the lowest penetrance dominant model. The Sib pair analysis, using combined TNFalpha and TNFbeta haplotypes, demonstrated a TNF allele sharing between affected sib-pairs which did not exceed the expected 50%. These results suggest that genetic factors may partially influence the disease onset and the progression rate in sibling pairs. A recall bias and/or an 'anticipation phenomenon' could explain the development of MS at an older age in parents than in their children. In this small-sized cohort of MS Italian families no significant associations were confirmed between TNF polymorphism and MS.

Adult↗
PubMed1999

Predictive markers of pre-eclampsia in hypertensive disorders of pregnancy.

OBJECTIVE: The aim of this work is to assess the most widespread methods currently proposed and two new markers for predicting the development of pre-eclampsia in pregnant women with hypertension. METHODS: The study involved 212 pregnant Caucasian women: 104 normotensive, 68 pregnancy-induced hypertensive and 40 chronic hypertensive. Blood and urine were sampled between 28 and 30 weeks gestation. All 108 hypertensive pregnant women, at the time of sampling, demonstrated proteinuria below 0.3 g/24 h. The following laboratory tests were performed: fibronectin, antithrombin-III, alpha-1-microglobulin, U-N-acetyl-beta-glucosaminidase, uric acid and albumin excretion rate. Student's t-test, discriminant analysis and chi2 (chi-square) test were used as statistical methods. A P value less than 0.05 was considered significant. RESULTS: After discriminating analysis, only three of the six variables analyzed were able to discriminate patients who would develop pre-eclampsia from the remaining hypertensive pregnant women: microalbuminuria, uric acid and fibronectin (chi2 = 29.122, P < 0.01). CONCLUSIONS: In agreement with previous studies, albumin excretion rate appeared to be the best predictive test for pre-eclampsia in hypertensive pregnant women, giving a higher positive predictive value and specificity (87.5 and 98.9%, respectively).

Adult↗
PubMed1999

Immune response following fresh arterial homograft replacement for aortoiliac graft infection.

INTRODUCTION: this prospective study defines the immune response to fresh arterial homograft replacement for graft infection. MATERIALS AND METHODS: ten patients who underwent ABO-compatible homograft transplantation were studied for anti-HLA antibody production, and CD3-CD4-CD8-positive lymphocytes subset. Immunological studies were performed preoperatively, and at early (1, 3, 7 days) and late (1, 3, 6, 12, 18, 24 months) follow-up. All patients received immunosuppressive treatment with cyclosporine (1-3 mg/kg/day). Abdominal CT scans were performed postoperatively at the 1, 6, 12, 18, 24 months follow-up. RESULTS: preoperatively, antibodies could not be detected. Postoperatively, as from 1st month post-transplant, a progressive increase in % PRA was observed in all patients, up to the 12th month of follow-up. Subsequently, at 18 and 36 months, a progressive decrease in % PRA was detected. Data showed that the recipient antibodies were directed against donor-specific antigens. During the immediate postoperative period (1, 3, 7 days) CD3- and CD4-positive T lymphocytes slightly increased, whereas CD8 simultaneously decreased. Later, CD3 and CD4 progressively decreased and CD8 increased. Clinically, all patients were cured of infection at late follow-up. CT scans showed thickening of the aortic wall (range: 2.5-4.5 mm), with no signs of aneurysmal degeneration. CONCLUSIONS: fresh arterial homografts are immunogenic. Implanted homografts induce a strong anti-HLA antibody response, similar to chronic rejection, in spite of immunosuppressive treatment.

ABO Blood-Group System↗
PubMed1999

Cardiovascular disease and the kidney: an epidemiologic overview.

Essential hypertension and congestive heart failure (CHF) are examples of cardiovascular disorders that may cause renal failure, although sometimes a primary kidney defect may lead to hypertension. Renal damage in malignant and severe hypertension is dramatic, extensive, and rapidly progressive, although nephrosclerotic damage, which develops slowly and appears late in hypertension, is a rare cause of morbidity because mild to moderate hypertension is now the most common form. However, the incidence of end-stage renal failure associated with hypertension is markedly increasing, perhaps because of underdiagnosis of renal damage in hypertension, insufficient lowering of blood pressure in clinical practice, or inability of antihypertensive drugs to lower blood pressure sufficiently to preserve the kidney, a goal that may need specific drugs that act, for example, on the renin-angiotensin system (RAS). Renal vasoconstriction and reduction of renal blood flow are early companions of cardiac insufficiency and may be involved in the development of sodium and water retention. Profound reduction of cardiac output and arterial hypotension in severe CHF may lead to acute renal failure. Chronic renal insufficiency is associated with elevated cardiovascular morbidity and mortality. Renal impairment is often caused by a disease process, such as diabetes mellitus, that involves both the cardiovascular system and the kidney. When the primary disease is renal, possible reasons for an association include renal-dependent increase in blood pressure, activation of the RAS, overproduction of other vasoactive substances of renal origin, and electrolyte imbalances leading to fatal arrhythmias.

Animals↗
PubMed1999

Colorectal cancer and the Muir-Torre syndrome in a Gypsy family: a review.

OBJECTIVES: The Muir-Torre syndrome (MTS) is characterized by an autosomal dominant predilection to sebaceous adenomas, sebaceous carcinomas, and multiple keratoacanthomas, in concert with the cancer phenotype of hereditary nonpolyposis colorectal cancer (HNPCC). Proof that patients showing a familial aggregation of MTS's cutaneous signs in combination with a specific pattern of visceral cancers which are consonant with an HNPCC diagnosis has been buttressed by the discovery of hMSH2 and hMLH1 germ-line mutations in such families. Our purpose in this investigation was to determine the germ-line mutation in a Gypsy family with MTS in concert with HNPCC cancer features, and to provide genetic counseling. An added objective for this paper is to review the literature on MTS. METHODS: We describe a Gypsy family with MTS in concert with HNPCC cancer features, as well as the molecular genetic and genetic counseling procedures used in the interest of improved compliance with cancer control recommendations. We review the clinical phenotype, natural history, and molecular genetics involved in the MTS variant HNPCC. RESULTS: An hMSH2 germ-line mutation was identified as the culprit germ-line mutation in this family. CONCLUSIONS: The presence of the hMSH2 germ-line mutation in this family provides powerful predictability of colorectal and other HNPCC integral cancers. The gastroenterologist must assume an important role in the diagnosis and management of MTS.

Adult↗
PubMed1999

Iodide symporter gene expression in normal and transformed rat thyroid cells.

OBJECTIVE: Decrease or loss of the Na+/I- symporter (NIS) activity profoundly affects the suitability of the use of radioiodine to detect or treat metastatic thyroid tissues. The aim of our study was to verify whether specific oncogene abnormalities were responsible for the alteration in NIS activity in thyroid cells. DESIGN AND METHODS: Expression of the NIS gene was investigated by Northern blot analysis in normal and in some oncogene-transformed cell lines with different degrees of malignancy which had lost the iodide uptake ability. RESULTS: NIS gene expression was up-regulated by TSH in a dose-dependent and time-dependent way in normal PC Cl 3 cells. The same effect was observed by activating the cAMP-dependent pathway by forskolin. Conversely, insulin and 12-O-tetradecanoylphorbol-13-acetate (TPA) showed a partial inhibitory effect on NIS gene expression. The oncogene-transformed cell lines PC v-erbA, PC HaMSV, PC v-raf, and PC E1A cells showed reduced NIS mRNA levels compared with the normal PC Cl 3 cells. Conversely, an almost complete absence of NIS gene expression was found in PC RET/PTC, PC KiMSV, PC p53(143ala), and PC PyMLV cell lines. CONCLUSIONS: Our data show that oncogene activation could play a role in affecting the iodide uptake ability in thyroid tumoral cells; different mechanisms are involved in the oncogene-dependent loss of NIS activity in transformed thyroid cells.

Animals↗
PubMed1999

Role of the renal nerves and angiotensin II in the renal function curve.

The relationship between renal perfusion pressure and urinary sodium is involved in arterial pressure regulation. The aim of this study was to investigate the role of renal nerves and angiotensin II in the pressure-natriuresis relationship. Experiments were performed in anaesthetised cats in which one kidney was surgically denervated. Renal perfusion pressure (RPP), renal blood flow (RBF) glomerular filtration rate (GFR, creatinine clearance), urinary volume (V) and sodium excretion (Una + V) were separately measured from both kidneys. RPP was progressively reduced in two consecutive steps by a suprarenal aortic snare. Two groups of animals were studied: the first without any pharmacological treatment (Untreated), the second during treatment with an angiotensin converting enzyme inhibitor (Captopril, 0.4 mg/Kg intravenously followed by an infusion of 0.4 mg/Kg/h). In the Untreated group RPP was reduced from 152.4 +/- 7.3 to 113.6 +/- 5.8 and 83.0 +/- 4.4 mmHg during the first and second step respectively. RBF and GFR were only slightly reduced during the second step of reduced RPP. In control conditions V and UNa + V were greater in the denervated compared to the innervated kidney. The graded decrease in RPP reduced both V and UNa + V in the innervated as well as in the denervated kidney. In the Captopril group V and UNa + V were larger than in the Untreated group in both the innervated and the denervated kidney. A decrease of RPP similar to that observed in the Untreated group, produced similar haemodynamic changes. Also in the Captopril group the graded decrease in RPP reduced both V and UNa + V in the innervated as well as in the denervated kidney. Matching UNa + V against RPP values significant correlations were found in the innervated and denervated kidneys of both groups. Both renal denervation and ACE inhibition were accompanied by an increased gain of the pressure-natriuresis curve, but only renal denervation shifted the crossing of the pressure axis to the left. In the ACE inhibited animals renal denervation only shifted the curve to the left. In conclusion our data suggest that i) at each level of RPP renal nerves and angiotensin II decrease renal sodium excretion, ii) renal nerves and angiotensin II increase the slope of the renal function curve, iii) renal nerves shift to the right the renal function curve.

Angiotensin II↗