PubMed Health⌕ Search

Biomedical subjects

E Ranieri

Publications and source records attributed to E Ranieri.

At least 55 records · Page 3Linked to original sources
PubMed1996

High glucose concentration induces the overexpression of transforming growth factor-beta through the activation of a platelet-derived growth factor loop in human mesangial cells.

High glucose concentration has been shown to induce the overexpression of transforming growth factor (TGF)-beta 1 mRNA and protein in different cell types, including murine mesangial cells, thus possibly accounting for the expansion of mesangial extracellular matrix observed in diabetic glomerulopathy. In the present study, we evaluated platelet-derived growth factor (PDGF) B-chain and PDGF-beta receptor gene expression in human mesangial cells (HMCs) exposed to different concentrations of glucose and then sought a possible relationship between a PDGF loop and the modulation of TGF-beta 1 expression. HMC [3H]thymidine incorporation was upregulated by 30 mmol/L glucose (HG) up to 24 hours, whereas it was significantly inhibited at later time points. Neutralizing antibodies to PDGF BB abolished the biphasic response to HG, whereas anti-TGF-beta antibodies reversed only the late inhibitory effect of hyperglycemic medium. HG induced an early and persistent increase of PDGF B-chain gene expression, as evaluated by reverse transcriptase polymerase chain reaction, whereas PDGF-beta receptor mRNA increased by twofold after 6 hours, thereafter declining at levels 70% lower than in controls after 24 hours. 125I-Labeled PDGF BB binding studies in HMCs exposed to HG for 24 hours confirmed the decrease of PDGF-beta receptor expression. TGF-beta 1-specific transcripts showed 43 and 78% increases after 24 and 48 hours of incubation in HG, respectively, which was markedly diminished by anti-PDGF BB neutralizing antibodies or suramin. We conclude that HG induces an early activation of a PDGF loop that, in turn, causes an increase of TGF-beta 1 gene expression, thus modulating both HMC proliferation and mesangial matrix production.

Cell Division↗
PubMed1995

Biosynthesis of C3 by human mesangial cells. Modulation by proinflammatory cytokines.

Deposits of complement (C) components are found in the glomeruli of patients with various glomerulonephritides without detectable immunoglobulins, thus suggesting a pathogenetic role of the locally produced proteins of this system. In the present study, we have examined human mesangial cells (HMC) for their ability to secrete C3. Three different cell lines were examined and all showed a basal production of C3, which was up-regulated following stimulation with IL-1 beta. IL-6 had no direct stimulatory effect on its own, but synergized with IL-1 to induce an increased production of C3 in the culture supernatant and its relative amount was confirmed by SDS-PAGE and immunoblot. Another agonist such as lipopolysaccharide was not able to induce any significant C3 synthesis. Analysis of C3 HMC gene expression, performed by both reverse transcription-polymerase chain reaction of isolated RNA and Northern blot, confirmed the parallel increase of the specific transcript under IL-1 beta and IL-1 beta + IL-6 stimulation. From these data we conclude that production of C3 in the mesangium could have a pathophysiologic relevance.

Base Sequence↗
PubMed1995

The sensitivity of ultrasound and serum alpha-fetoprotein in population-based antenatal screening for neural tube defects. South Australia 1986-1991.

OBJECTIVE: To determine the sensitivity of antenatal screening methods for neural tube defects in population-based screening in South Australia in 1986-1991, and whether ultrasound can replace serum alpha-fetoprotein screening in terms of achieving an equivalent level of sensitivity. DESIGN AND SETTING: Ascertainment of all births and terminations of pregnancy with neural tube defects from multiple sources for 1986-1991 in South Australia. Serum and amniotic fluid alpha-fetoprotein results were obtained from the only laboratory performing the tests as a Statewide antenatal screening programme, and information on ultrasound screening from case notifications, hospital case records and medical practitioners who cared for the women. SUBJECTS: All 243 births and terminations of pregnancy with neural tube defects in South Australia in 1986-1991. MAIN OUTCOME MEASURES: The sensitivity of individual screening methods and of all methods used, particularly for spina bifida. RESULTS: For pregnancies with neural tube defects screened by any method (serum alpha-fetoprotein, ultrasound or amniocentesis), 86% sensitivity was achieved. Ultrasound screening for anencephaly achieved 100% sensitivity even in low risk pregnancies, compared with 92% for serum alpha-fetoprotein. For spina bifida, the sensitivity of ultrasound screening increased with the level of risk in pregnancy: it was 60% in low risk pregnancies, which was equivalent to that of serum alpha-fetoprotein screening (64%); 89% in high risk pregnancies and 100% for women referred for confirmation of a suspected spina bifida by another ultrasonographer (chi 1(2) for trend = 23.49, P < 0.0001). Ultrasound screening in high risk pregnancies for spina bifida achieved higher sensitivity in teaching hospitals compared with other ultrasound services in the State (97% vs 65%), but sensitivity was equivalent for low risk pregnancies. It is estimated that, had the serum screening programme not been in place, the level of sensitivity achieved for spina bifida by ultrasound and amniocentesis would have been 62% compared with the actual situation of 76% with the programme in existence, a difference of nearly 15% (95% CI 2.5 to 26.7) (chi 1(2) = 5.45, P = 0.02). CONCLUSIONS: Antenatal screening for neural tube defects in South Australia achieved a higher level of sensitivity with the maternal serum alpha-fetoprotein programme in place. We conclude that the serum screening programme should continue in South Australia pending a significant improvement in the sensitivity of routine ultrasound screening for spina bifida.

Anencephaly↗
PubMed1995

Cultured human mesangial cells produce both type 1 and type 2 plasminogen activator inhibitors.

Cultured human mesangial cells (HMC) derived from normal kidneys have been shown to synthesize tissue-type plasminogen activator (t-PA) and excess amounts of PA inhibitor type 1 (PAI-1). Conflicting results have been obtained concerning the production of urokinase-type PA (u-PA) and efforts to show PA inhibitor 2 (PAI-2) met with failure. We evaluated the fibrinolytic profile of cultured HMC lines obtained from 12 patients with renal carcinoma and one cadaveric kidney donor. Subconfluent cells (third passage) were incubated overnight in serum-free medium. t-PA, u-PA, PAI-1 and PAI-2 antigens were assayed by ELISA methods and PA and PAI activities by amidolytic methods both in conditioned medium (CM) and cell extracts (CE). Besides PAI-1, PAI-2 antigen was detected in all but one HMC lines. At variance with the former, which was largely released in the culture medium, PAI-2 was mainly cell-associated. t-PA antigen was found in all but two cell lines while u-PA antigen was detected in relatively high concentrations in 8 cell lines. PA activity, identified as u-PA by functional and immunological criteria, was measured in CM of six of the eight u-PA producing cell lines, whereas PAI activity was undetectable or very low in CM of all cell lines, suggesting that PAI-1 was largely inactive. Functional assays of cell extracts demonstrated the presence of PA activity, again identified as u-PA, only in samples (five lines) containing u-PA antigen in excess over PAI-2. PAI activity was found instead in the extracts in which the inhibitor was higher than the activator (six lines) and was identified as PAI-2, as it inhibited u-PA but not single-chain t-PA and was neutralized by a polyclonal anti-PAI-2 antibody. The heterogeneous fibrinolytic pattern of HMC lines was confirmed by mRNA analysis of three representative lines. Results were similar when HMC lines at passage five were used, except that the u-PA content was significantly reduced both in CM and CE. These findings indicate that the fibrinolytic profile of cultured HMC is more complex than previously reported. The production of large amounts of PAI-2 may represent an additional control mechanism of proteinase activity.

Blotting, Northern↗
PubMed1994

Neonatal screening for cystic fibrosis using immunoreactive trypsinogen and direct gene analysis: four years' experience.

OBJECTIVE: To assess the performance and impact of a two tier neonatal screening programme for cystic fibrosis based on an initial estimation of immunoreactive trypsinogen followed by direct gene analysis. DESIGN: Four year prospective study of two tier screening strategy. First tier: immunoreactive trypsinogen measured in dried blood spot samples from neonates aged 3-5 days. Second tier: direct gene analysis of cystic fibrosis mutations (delta F508, delta I506, G551D, G542X, and R553X) in samples with immunoreactive trypsinogen concentrations in highest 1% and in all neonates with meconium ileus or family history of cystic fibrosis. SETTING: South Australian Neonatal Screening Programme, Adelaide. SUBJECTS: All 88,752 neonates born in South Australia between December 1989 and December 1993. INTERVENTIONS: Neonates with two identifiable mutations were referred directly for clinical assessment and confirmatory sweat test; infants with only one identifiable mutation were recalled for sweat test at age 3-4 weeks. Parents of neonates identified as carriers of cystic fibrosis mutation were counselled and offered genetic testing. MAIN OUTCOME MEASURES: Identification of all children with cystic fibrosis in the screened population. RESULTS: Of 1004 (1.13%) neonates with immunoreactive trypsinogen > or = 99th centile, 912 (90.8%) had no identifiable mutation. 23 neonates were homozygotes or compound heterozygotes; 69 carried one identifiable mutation, of whom six had positive sweat tests. Median age at clinical assessment for the 29 neonates with cystic fibrosis was 3 weeks; six had meconium ileus and two had affected siblings. 63 neonates were identified as carriers of a cystic fibrosis mutation. Extra laboratory costs for measuring immunoreactive trypsinogen and direct gene analysis were $A1.50 per neonate screened. CONCLUSION: This strategy results in early and accurate diagnosis of cystic fibrosis and performs better than screening strategies based on immunoreactive trypsinogen measurement alone.

Cystic Fibrosis↗
PubMed1994

Trapidil inhibits human mesangial cell proliferation: effect on PDGF beta-receptor binding and expression.

Mesangial cell (MC) proliferation, a histopathologic feature common to many human glomerular diseases, is regulated by several growth factors through their binding to specific cell surface receptors. Platelet-derived growth factor (PDGF) is a peptide exerting a potent mitogenic activity on MC. Recently, an increased expression of both PDGF protein and its receptor has been localized in the mesangial areas of several experimental as well as human proliferative glomerulonephritides (GN). Thus, it may be postulated that the inhibition of PDGF action could prevent MC proliferation during mesangial proliferative GN. Trapidil, an antiplatelet drug, has been shown to inhibit the growth of several cell types both in vitro and in vivo. The present study was aimed at evaluating the effect of Trapidil on human MC in vitro. The addition of 100 to 400 micrograms/ml Trapidil significantly reduced cell proliferation induced by different growth factors (FCS, PDGF-BB, bFGF, EGF), the highest inhibitory effect being on PDGF-BB stimulated MC growth. The effect of the drug was dose-dependent and seemingly specific: aspirin was devoid of any anti-proliferative action, while dypiridamole proved to be toxic. Receptor binding experiments showed that Trapidil competitively inhibited 125I-PDGF-BB binding to its cell surface receptors, without inducing receptor internalization, at least after short-term (2 hr) incubation. In contrast, long-term (48 hr) exposure to 400 micrograms/ml Trapidil caused a sharp increase of PDGF-BB binding. Similar effects on cell proliferation and 125I-PDGF-BB binding were observed when NIH-3T3 fibroblasts were exposed to the test substance.(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1994

[Role of Culex quinquefasciatus in the transmission of bancroftian filariasis in the Federal Islamic Republic of Comoros (Indian Ocean)].

In October 1988-January 1989, as a part of a malaria and filariasis control programme in Federal Islamic Republic of Comoros an entomological survey was carried out in 19 rural and urban localities of Grande Comore. Anjouan and Moheli Islands. The potential breeding places were examined and pyrethrum spray catches were made to evaluate the indoor resting densities of mosquitos. A total of 14.578 adult mosquitos potential vectors of filariasis was collected: 94.5% Culex quinquefasciatus, 3.5% Anopheles gambiae s. str. 1.9% A. funestus and 0.1% other anopheline species. A. funestus, uniformly spread in Moheli, was present only in the south-west coast of Anjouan and absent in Grande Comore. A. gambiae and Cx quinquefasciatus were present in Grande Comore. A. gambiae and Cx quinquefasciatus were present in the three islands with different densities in the villages. Only Cx quinquefasciatus specimens la maximum of 150 for each locality) were dissected to search filaria larvae being the Anopheles specimens used to evaluate the malaria transmission. The global infection rate (9.4%) and the infectivity rate (0.9%) observed in Cx quinquefasciatus are higher than indices reported in previous surveys. All the larvae in the third development instar (L3) were identified as Wuchereria bancrofti. The results suggest that in FIR of Comoros W. bancrofti is well adopted to local Cx quinquefasciatus population. Because of the presence of high mosquito density this species plays a prominent role in the transmission of lymphatic filariasis in that area. The high transmission levels calls for the implementation of a specific control program.

Animals↗
PubMed1994

Profiles of immunoregulatory cytokine production in vitro in patients with IgA nephropathy and their kindred.

We hypothesized that the altered immunoglobulin synthesis and/or lymphocyte function apparent in patients with IgA nephropathy (IgAN) is due to a primary defect in lymphokine regulation. In addition, we reasoned that such changes in lymphokine production might be, at least partially, genetically determined. To assess the extent of lymphocyte abnormalities, we investigated the profile of cytokine production from peripheral blood mononuclear cells (PBMC) in 34 IgAN patients and 44 of their first degree relatives, 10 of whom had persistent microhaematuria. Compared with healthy volunteers (n = 34), PBMC from patients showed increased IL-2 production both spontaneously or after phytohaemagglutinin (PHA) (20 micrograms/ml) stimulation, whereas IL-4 and interferon-gamma (IFN-gamma) production were significantly higher only after stimulation. Microhaematuric relatives had a similar pattern of cytokine production, whereas non-microhaematuric relatives showed no significant difference versus normals. The altered pattern of cytokine production appeared to be quite specific to IgAN patients and their microhaematuric relatives, because patients with other forms of primary glomerulonephritis (n = 17) did not differ from normal individuals. Patients and relatives that hyperproduced IL-4 were also hyperproducers of IL-2. No such congruence was seen in any other group or with any other pairing of cytokines. We propose that a subpopulation of IgAN patients bear lymphocytes intrinsically hyperresponsive. Among those individuals such hyperresponsiveness may be causally related to the pathogenesis and/or character of IgAN.

Adolescent↗
PubMed1994

Expression of platelet-derived growth factor receptors in normal and diseased human kidney. An immunohistochemistry and in situ hybridization study.

We studied the expression of PDGF-alpha and -beta receptors in 10 normal and 40 pathologic human kidneys (five minimal change disease, five membranous nephropathy, 25 IgA nephropathy, five lupus nephritis), by both immunohistochemistry and in situ hybridization techniques. In normal-appearing kidneys, both PDGF-alpha and -beta receptors were expressed at the glomerular and interstitial level, the latter receptor more intensely than the former. The distribution and degree of expression of both receptors in nonproliferative glomerulonephritides were comparable with those found in normal-appearing kidneys. PDGF-beta receptor gene and protein expression were upregulated in proliferative nephritides both at the glomerular and the interstitial level and strictly correlated with the grade of histologic lesions. Finally, PDGF beta receptor expression was observed at a low level in normal-appearing renal vessels, and strikingly increased in injured arteries. Diseased kidneys displayed only a slight increase of PDGF-alpha receptor expression, chiefly at the interstitial level. Noteworthy, a few cases of lupus nephritis showed a moderate increase of PDGF-alpha receptor also at the glomerular level. These data establish PDGF-beta receptor activation as a candidate for driving glomerular and interstitial proliferation and, probably, expansion of extracellular matrix in proliferative glomerulonephritis, while the role of PDGF-alpha receptor activation at the renal level remains to be elucidated.

Cells, Cultured↗
PubMed1994

In vitro immunoglobulin production in relatives of patients with IgA nephropathy.

We hypothesized that the altered immunoglobulin synthesis and/or lymphocyte function apparent in patients with IgA nephropathy might be, at least partially, genetically determined. To address this hypothesis, immunoglobulin production by peripheral blood mononuclear cells in 22 patients with IgA nephropathy and 44 of their first degree relatives was investigated. Spontaneous overproduction of IgA1 and IgM from patients' PBMC was found. After pokeweed mitogen stimulation, both patients and relatives produced significantly more IgA1 and IgM than normal subjects. However, relatives showed a higher index of stimulation by pokeweed mitogen compared to both normals and patients. No differences were revealed in IgA2 or IgG subclass production among the groups. We propose that patients with IgAN have defects in immunoregulation that likely depend upon the genetic substrate in the patients' relatives. Such defect may reside not with the balance between help for and suppression of a particular isotype, but rather with the overall balance of isotypes in response to a particular antigenic challenge.

Adult↗
PubMed1993

Prevalence of neural tube defects in South Australia, 1966-91: effectiveness and impact of prenatal diagnosis.

OBJECTIVE: To determine trends in total prevalence of neural tube defects in South Australia during 1966-91, the impact of prenatal diagnosis on birth prevalence, and the effectiveness of prenatal screening for neural tube defects in 1986-91. DESIGN: All births and terminations of pregnancy affected by neural tube defects and information on prenatal screening were ascertained from multiple sources including the South Australian perinatal and abortion statistics collections, birth defects register, and state maternal serum alpha fetoprotein screening programme. SETTING: Southern Australia. SUBJECTS: All 1058 births and terminations of pregnancy affected by neural tube defects in 1966-91. MAIN OUTCOME MEASURES: Total prevalence and birth prevalence of individual and all neural tube defects. The proportion of screened cases detected prenatally. RESULTS: Total prevalence of neural tube defects during 1966-91 was 2.01/1000 births with no upward or downward trend. However, birth prevalence fell significantly (by 5.1% a year), with an 84% reduction from 2.29/1000 births in 1966 to 0.35/1000 in 1991 (relative risk = 0.16, 95% confidence interval 0.07 to 0.34). The fall was 96% for anencephaly and 82% for spina bifida. 85% of defects, both open and closed, were detected before 28 weeks' gestation in women screened by serum alpha fetoprotein or mid-trimester ultrasonography, or both, in 1986-91 (99.0% for anencephaly and 75.7% for spina bifida). CONCLUSIONS: While the total prevalence of neural tube defects in South Australia remained stable, prenatal diagnosis and termination of pregnancy resulted in an 84% fall in birth prevalence during 1966-91. Screening detected over four fifths of cases in 1986-91.

Confidence Intervals↗
PubMed1993

Abnormalities of the IgA immune system in members of unrelated pedigrees from patients with IgA nephropathy.

In the last few years many investigators have reported the recurrence of primary IgA nephropathy (IgAN) or the presence of persistent microhaematuria and/or proteinuria in family members of patients with IgAN. Our study was undertaken to investigate the relevance of abnormalities in the regulation of the IgA and IgM immune system in microhaematuric and asymptomatic family members of IgAN patients. Fifty-four out of 120 members of nine unrelated pedigrees were examined by urinalysis; polymeric IgA (pIgA), IgA rheumatoid factor (IgARF), IgA1-IgG immune complexes (IgA 1-IgG IC) and IgA 1-IgM IC, and other immunoglobulins were measured in serum samples. Moreover, we studied the production of immunoglobulins, pIgA and IgARF by peripheral blood mononuclear cells (PBMC) in basal conditions and after pokeweed mitogen (PWM) stimulation. Our data demonstrate that persistent microhaematuria was present in 24% of relatives. High serum levels of IgA, mainly pIgA and IgARF, IgA 1-IgG IC and IgA 1-IgM IC occurred in 66% of relatives. Abnormal spontaneous production of IgA by PBMC and after PWM stimulation was present in 64% of family members. Interestingly, high serum levels of IgM and abnormal production of this immunoglobulin by PBMC were observed in relatives. However, the immunological abnormalities did not correlate in any way with the presence of urinary abnormalities such as microhaematuria, which was most likely determined by an underlying glomerular alteration.

Adolescent↗
PubMed1993

Modifying an enzyme immunoassay of immunoreactive trypsinogen to use time-resolved fluorescence.

A coated microtiter-well, enzyme-linked immunometric assay for quantifying immunoreactive trypsinogen in dried blood spots was modified to use time-resolved fluorescence of europium in place of end-point enzymatic color development as the quantification step. The streptavidin-horseradish peroxidase and color development solutions supplied as packaged reagents were replaced by europium-labeled avidin, and the signal was developed with commercially available enhancement solution and read by time-resolved fluorescence. The change of label from enzyme to europium increased the dynamic range of the assay by about 5-fold, reduced the detection limit 10-fold, and halved the intra- and interassay imprecision. The improved analytical precision and stability of the modified assay resulted in a more precise description of the population distribution of immunoreactive trypsinogen values in newborns, showing less variance in the upper centiles. This effect is of paramount importance when using this assay for neonatal screening for cystic fibrosis.

Avidin↗