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C Bagnis

Publications and source records attributed to C Bagnis.

At least 19 recordsLinked to original sources
PubMed2002

A Nod Scid mouse model to study human prostate cancer.

Prostate cancer is the second cause of cancer mortality in men in Western countries. To study new therapeutic approaches such as gene therapy, animal models of human prostate cancer with metastatic behavior are mandatory. We used the Nod Scid mouse strain to develop an orthotopic animal model. Two androgen-independent cell lines (PC-3 and DU 145) were used. Local tumor growth and metastases were analyzed. The tumor take rates were close to those reported in the literature. However, a high frequency of various metastatic sites has been observed (liver, lung, spleen, adrenal, kidney, lymph node, and diaphragm). It can be concluded that the Nod Scid mouse is a relevant preclinical animal model to study human prostate cancer. Metastatic sites seem more numerous in comparison to other orthotopic mice models described.

Adenocarcinoma↗
PubMed2002

[Nephrotoxicity of amphotericin B].

Amphotericin B is widely used for severe life threatening fungal infections. Its use is limited by a dose-dependent nephrotoxicity manifested by a reduction in glomerular filtration rate and tubular dysfunction. An elevated creatinine associated with amphotericin B is not only a marker for renal dysfunction but is also linked to a substantial risk for the use of hemodialysis and a higher mortality rate; therefore amphotericin B nephrotoxicity is not a benign complication and its prevention is essential. Several manipulations have been proposed to try and minimize amphotericin B induced nephrotoxicity. Systematic hydration is crucial to minimize amphotericin B. Mannitol or intralipids administration were once suggested as protective based on anecdotal observational reports. Small prospective and randomized trials, however did not support a protective effect. Three new formulations have been developed in an attempts to improse both efficacy and tolerability: amphotericin B in lipid complex (ABLC, Abelcet). Colloidal dispersion (ABCD, Amphotec and amphotericin B liposome (Ambisome). Three prospectives randomized studies have clearly shown that Ambisome is less nephrotoxic than amphotericin B. Unfortunately the only randomized trial comparing Abelcet with amphotericin B is an open-label treatment of invasive candidiasis which was presented 5 years ago but never published as a full paper. Furthermore in a recent multicenter double-blind study it has been shown that Ambisome has a better safety profile than Abelcet with less chills/rigors and less nephrotocixity.

Amphotericin B↗
PubMed2001

Death of motoneurons induced by trophic deprivation or by excitotoxicity is not prevented by overexpression of SMN.

The telomeric copy of the survival motor neuron gene (SMN1) is deleted or mutated in all spinal muscular atrophy (SMA) patients and these patients present mainly a loss in spinal motoneurons. Although studies performed in HeLa cells suggest that SMN may be involved in the biogenesis and possibly in recycling of spliceosomal small nuclear ribonucleoproteins (snRNPs), no link has been established between this function and the consequence of the absence of SMN in the specific loss of motoneurons. We attempted to answer the question of whether SMN plays a direct role in motoneuron survival by transducing cultured motoneurons with lentiviral vectors coding either for an antisense Smn mRNA or for full-length or truncated forms of SMN. We studied their effect on survival under different anti- or proapoptotic culture conditions. Our results show that increased levels of SMN are unable to protect motoneurons from death induced by trophic deprivation or by excitotoxicity. These results suggest that SMN is not a survival factor per se for motoneurons. In addition, overexpression of a truncated form of SMN shown to induce a modified subcellular localization and to exert a dominant-negative effect on snRNP biogenesis and RNA splicing in HeLa cells was ineffective in modifying both localization and survival in motoneurons.

Animals↗
PubMed2001

Erythropoietin enhances recovery after cisplatin-induced acute renal failure in the rat.

BACKGROUND: Erythropoietin (Epo) is a growth factor whose synthesis mainly takes place in the kidney. Epo has been shown to support the growth not only of erythroid progenitor cells but also of certain other cell types. We attempted to establish whether Epo enhances the recovery from acute renal failure induced by cisplatin. METHODS: Sprague-Dawley rats were randomized into three groups. In the cisplatin group, animals received one intraperitoneal injection of cisplatin (6 mg/kg) and a daily injection of placebo for 9 days. In the cisplatin+Epo group, animals received intrapertoneal cisplatin and a daily injection of Epo (100 IU/kg) for 9 days. In the control group, animals received both placebo preparations alone. Para-aminohippuric acid and inulin clearances were determined after 4 and 9 days to evaluate renal blood flow and glomerular filtration rate. In addition, light microscopy and immunohistochemistry examinations were performed, and in situ proliferating cell nuclear antigen (PCNA) staining was done to estimate the degree of renal tubular cell regenerative activity. The potential role of epithelial growth factor (EGF) was evaluated by semi-quantitative assessment of EGF immunostaining. RESULTS: Renal blood flow and glomerular filtration rate decreased significantly in cisplatin and cisplatin+Epo groups versus control group at day 4. However, at day 9, they both were significantly greater in cisplatin+Epo-treated animals than in rats that had received cisplatin alone. Tubular cell regeneration was significantly enhanced at day 4 in cisplatin+Epo group, compared with cisplatin and control groups respectively. EGF immunostaining was not significantly different between the three groups. CONCLUSION: Epo significantly enhanced the rate of recovery from acute renal failure induced by cisplatin. PCNA staining indicated that Epo might act directly via stimulation of tubular cell regeneration.

Acute Kidney Injury↗
PubMed2001

Aquaporin 9 expression along the male reproductive tract.

Fluid movement across epithelia lining portions of the male reproductive tract is important for modulating the luminal environment in which sperm mature and reside, and for increasing sperm concentration. Some regions of the male reproductive tract express aquaporin (AQP) 1 and/or AQP2, but these transmembrane water channels are not detectable in the epididymis. Therefore, we used a specific antibody to map the cellular distribution of another AQP, AQP9 (which is permeable to water and to some solutes), in the male reproductive tract. AQP9 is enriched on the apical (but not basolateral) membrane of nonciliated cells in the efferent duct and principal cells of the epididymis (rat and human) and vas deferens, where it could play a role in fluid reabsorption. Western blotting revealed a strong 30-kDa band in brush-border membrane vesicles isolated from the epididymis. AQP9 is also expressed in epithelial cells of the prostate and coagulating gland where fluid transport across the epithelium is important for secretory activity. However, it was undetectable in the seminal vesicle, suggesting that an alternative fluid transport pathway may be present in this tissue. Intracellular vesicles in epithelial cells along the reproductive tract were generally poorly stained for AQP9. Furthermore, the apical membrane distribution of AQP9 was unaffected by microtubule disruption. These data suggest that AQP9 is a constitutively inserted apical membrane protein and that its cell-surface expression is not acutely regulated by vesicular trafficking. AQP9 was detectable in the epididymis and vas deferens of 1-wk postnatal rats, but its expression was comparable with adult rats only after 3--4 wk. AQP9 could provide a route via which apical fluid and solute transport occurs in several regions of the male reproductive tract. The heterogeneous and segment-specific expression of AQP9 and other aquaporins along the male reproductive tract shown in this and in our previous studies suggests that fluid reabsorption and secretion in these tissues could be locally modulated by physiological regulation of AQP expression and/or function.

Aging↗
PubMed2001

CD154 costimulated ovine primary B cells, a cell culture system that supports productive infection by bovine leukemia virus.

Bovine leukemia virus (BLV) is closely associated with the development of B-cell leukemia and lymphoma in cattle. BLV infection has also been studied extensively in an in vivo ovine model that provides a unique system for studying B-cell leukemogenesis. There is no evidence that BLV can directly infect ovine B cells in vitro, and there are no direct data regarding the oncogenic potential of the viral Tax transactivator in B cells. Therefore, we developed ovine B-cell culture systems to study the interaction between BLV and its natural target, the B cell. In this study, we used murine CD154 (CD40 ligand) and gamma-chain-common cytokines to support the growth of B cells isolated from ovine lymphoid tissues. Integrated provirus, extrachromosomal forms, and viral transcripts were detected in BLV-exposed populations of immature, rapidly dividing surface immunoglobulin M-positive B cells from sheep ileal Peyer's patches and also in activated mature B cells isolated from blood. Conclusive evidence of direct B-cell infection by BLV was obtained through the use of cloned B cells derived from sheep jejunal Peyer's patches. Finally, inoculation of sheep with BLV-infected cultures proved that infectious virus was shed from in vitro-infected B cells. Collectively, these data confirm that a variety of ovine B-cell populations can support productive infection by BLV. The development of ovine B-cell cultures permissive for BLV infection provides a controlled system for investigating B-cell leukemogenic processes and the pathogenesis of BLV infection.

Animals↗
PubMed2001

Na+/H+-exchange activity and immunolocalization of NHE3 in rat epididymis.

An acidic luminal pH in the epididymis and vas deferens (VD) helps maintain mature sperm in an immotile state during storage. We have previously shown that the majority of proton secretion in the VD is due to the activity of the vacuolar H+-ATPase. Acidification is dependent on luminal sodium in more proximal regions of the epididymis, and we examined the distribution of the Na+/H+ exchanger, NHE3, by immunofluorescence and measured Na+/H+ exchange (NHE) activity in isolated epididymal tubules. NHE3 was detected in the apical pole of nonciliated cells of the efferent ducts and principal cells (PC) of the epididymis. No staining was seen in the distal cauda epididymidis and the VD. Isolated tubules from the distal initial segment (DIS) and proximal cauda epididymidis were perfused in vitro and loaded with the pH-sensitive dye 2',7'-bis(carboxyethyl)-5(6')-carboxyfluorescein. Ethylisopropyl amiloride (EIPA) (50 microM) reduced the initial rate of intracellular pH recovery (dpH(i)/dt), in response to an acute acid load, by 51% and 45% in the DIS and cauda epididymidis, respectively. In the DIS, removal of luminal sodium reduced dpH(i)/dt by 52%. HOE694 (50 microM) inhibited all EIPA-sensitive dpH(i)/dt in the DIS, despite the previously reported absence of NHE2 in this region (Cheng Chew SB, Leung GPH, Leung PY, Tse CM, and Wong PYD, Biol Reprod 62: 755-758, 2000). These data indicate that HOE694- and EIPA-sensitive Na+/H+ exchange may participate, together with the H+-ATPase, in luminal acidification in the male excurrent duct.

Animals↗
PubMed2001

Remodeling the cellular profile of collecting ducts by chronic carbonic anhydrase inhibition.

Factors regulating the differentiated phenotype of principal cells (PC) and A- and B-intercalated cells (IC) in kidney collecting ducts are poorly understood. However, we have shown previously that carbonic anhydrase II (CAII)-deficient mice have no IC in their medullary collecting ducts, suggesting a potential role for this enzyme in determining the cellular composition of this tubule segment. We now report that the cellular profile of the collecting ducts of adult rats can be remodeled by inhibiting CA activity in rats by using osmotic pumps containing acetazolamide. The 31-kDa subunit of the vacuolar H(+)-ATPase, the sodium/hydrogen exchanger regulatory factor NHE-RF, and the anion exchanger AE1 were used to identify IC subtypes by immunofluorescence staining, while aquaporin 2 and aquaporin 4 were used to identify PC. In the cortical collecting ducts of animals treated with acetazolamide for 2 wk, the percentage of B-IC decreased significantly (18 +/- 2 vs. 36 +/- 4%, P < 0.01) whereas the percentage of A-IC increased (82 +/- 2 vs. 64 +/- 4%, P < 0.01) with no change in the percentage of total IC in the epithelium. In some treated rats, B-IC were virtually undetectable. In the inner stripe of the outer medulla, the percentage of IC increased in treated animals (48 +/- 2 vs. 37 +/- 3%, P < 0.05) and the percentage of PC decreased (52 +/- 2 vs. 63 +/- 3%, P < 0.05). Moreover, IC appeared bulkier, protruded into the lumen, and showed a significant increase in the length of their apical (20.8 +/- 0.5 vs. 14.6 +/- 0.4 microm, P < 0.05) and basolateral membranes (25.8 +/- 0.4 vs. 23.8 +/- 0.5 microm, P < 0.05) compared with control rats. In the inner medullary collecting ducts of treated animals, the number of IC in the proximal third of the papilla was reduced compared with controls (11 +/- 4 vs. 40 +/- 11 IC/mm(2), P < 0.05). These data suggest that CA activity plays an important role in determining the differentiated phenotype of medullary collecting duct epithelial cells and that the cellular profile of collecting ducts can be remodeled even in adult rats. The relative depletion of cortical B-IC and the relative increase in number and hyperplasia of A-IC in the medulla may be adaptive processes that would tend to correct or stabilize the metabolic acidosis that would otherwise ensue following systemic carbonic anhydrase inhibition.

Acetazolamide↗
PubMed2000

Gene transfer to hepatocellular carcinoma: transduction efficacy and transgene expression kinetics by using retroviral and lentiviral vectors.

Gene therapy is an attractive therapy for hepatocarcinoma, and several approaches have been studied using murine leukemia virus-derived retroviruses. We compared gene transfer efficacy and transgene expression kinetics after transduction of hepatocarcinoma cell lines using enhanced green fluorescent protein (EGFP)-expressing murine leukemia virus-derived retroviral vectors and HIV-derived lentiviral vectors. First, we showed that both retroviral and lentiviral vectors efficiently transduce cycling hepatocarcinoma cell lines in vitro. However, after cell cycle arrest, transduction efficacy remained the same for lentiviral vectors but it decreased by 80% for retroviral vectors. Second, we studied EGFP expression kinetics using lentiviral vectors expressing EGFP under the control of cytomegalovirus (CMV) or phosphoglycerolkinase (PGK) promoter. We show that the CMV promoter allows a stronger EGFP expression than the PGK promoter. However, in contrast to PGK-driven EGFP expression, which persists up to 2 months after transduction, CMV-driven EGFP expression rapidly decreased with time. This phenomenon is due to promoter silencing, and EGFP expression can be restored in transduced cells by using transcription activators such as interleukin-6 or phorbol myristate acetate/ionomycin and, to a lesser extent, the demethylating agent 5'-azacytidine. Altogether, our results suggest that lentiviral vectors, which allow efficient transduction of hepatocarcinoma cell lines with a strong and a sustained expression according to the promoter used, are promising tools for gene therapy of hepatocarcinomas.

Azacitidine↗
PubMed1999

Renal effects of low and isoosmolar contrast media on renal hemodynamic in a normal and ischemic dog kidney.

RATIONALE AND OBJECTIVES: The authors investigated the comparative effects of a nonionic dimer contrast medium (iodixanol) with an ionic low osmolar contrast media (locm) (ioxaglate) on renal blood in a normal and an ischemic dog kidney. METHODS: Six dogs were studied for two periods. During the first period (the control period) a renal arteriography was performed with either iodixanol (Visipaque) or ioxaglate (Hexabrix) in a randomized order. Twenty minutes after applying a suprarenal clamp just above the right renal artery, two selective intrarenal contrast media administrations were performed at 30-minute intervals in a randomized order (ischemic period). RESULTS: During the control period ioxaglate and iodixanol induced no change in mean arterial blood pressure and pulse rate. The maximum decrease in renal blood flow (rbf) observed with ioxaglate was 19 +/- 4%. The maximum decrease in rbf observed with iodixanol was 51 +/- 16% versus control period (P = 0.05 compared with ioxaglate). During the ischemic period, renal perfusion pressure was 72 +/- 2 mm Hg and 73 +/- 2 mm Hg before iodixanol and ioxaglate administration, respectively (P = NS). Iodixanol induced a 61 +/- 11% decrease in RBF. These changes were significantly higher than those observed with ioxaglate during the control period and with the control ischemic period. Ioxaglate induced a maximum 11 +/- 6% decrease in RBF at 1 min (P < 0.05 versus iodixanol). These modifications were not significantly higher than those observed during the control period. CONCLUSIONS: In this study the authors found that the renal effect of iodixanol are markedly more pronounced than that of ioxaglate. In the setting of ischemia the effects of iodixanol were only slightly enhanced whereas those of ioxaglate were not modified.

Analysis of Variance↗
PubMed1999

In vivo rescue of a silent tax-deficient bovine leukemia virus from a tumor-derived ovine B-cell line by recombination with a retrovirally transduced wild-type tax gene.

The lack of bovine leukemia virus (BLV) expression is a consistent finding in freshly isolated ovine tumor cells and in the B-cell lines derived from these tumors. In order to gain further insight into the mechanisms of BLV silencing in these tumors, we have used the YR2 B-cell line, which was derived from the leukemic cells of a BLV-infected sheep. This cell line contains a single, monoclonally integrated, silent provirus, which cannot be reactivated either by stimulation in vitro or by in vivo injection of the tumor cells or cloned proviral DNA in sheep. Sequence analysis of the tax gene from the YR2 cell line identified two G-to-A transitions (G7924 to A7924 and G8149 to A8149) that result in E-to-K amino acid changes at positions 228 and 303 in the Tax protein. Following retroviral vector-mediated transfer of a wild-type tax gene into YR2 cells, we showed that BLV mRNA, viral proteins, and virions were produced, demonstrating that the cellular factors required for virus expression were present in the original YR2 cell line. Injection of this transduced YR2 cell line in sheep led to the rescue of replication-competent BLV proviruses. The integrated competent proviruses exhibited unique chimeric tax genes, which arose from homologous recombination between the transduced wild-type tax and the YR2-derived tax sequences. Furthermore, in one of these functional recombinant proviruses, only the A8149-to-G8149 reversion was present, providing clear evidence that the defect underlying the silent phenotype in YR2 cells results from a single C-terminal E303-to-K303 amino acid substitution in the BLV Tax protein. Our observations suggest that a single strategically located mutation in tax provides a mechanism for BLV inactivation in B-cell tumors.

Animals↗
PubMed1999

Idiopathic calcium nephrolithiasis.

Calcium nephrolithiasis (CaNL) accounts for more than 70% of all renal stones, and its prevalence has increased in the last decades. Under this definition are included patients passing stones, composed of calcium oxalates and/or calcium phosphates. Current views of the pathogenesis of CaNL are based on the role of metabolic abnormalities which concur to render urines more conducive to crystallization. Therefore, the diagnostic approach is aimed at detecting these abnormalities, and the medical treatment assumes that a decrease in the risk of lithogenesis will result in remission or improvement of recurrences. The workup of the patients with CaNL begins with the analysis of passed stones and X-ray, sonography or other imaging techniques. Eligible patients, that is, both recurrent active stone formers and single-stone formers with individual risk factors, are considered for a metabolic evaluation, by which a number of blood and urine parameters are measured and others calculated. These include estimates of urine state of saturation with calcium and uric acid salts, net gastrointestinal alkali absorption, renal threshold of phosphate and other renal clearances and net acid and total nitrogen excretions. Basically, this screening is informative on renal function, metabolic abnormalities and their pathophysiology, risk of stone formation and dietary habits. During treatment it gives information about patient compliance and adverse effects of therapy. The cost of a comprehensive screening in Piedmont is 192,000 ITL (100 Euro) and rises to 300,000 ITL (154 Euro) if hormones and hydroxyproline are measured. In individual patients second- and third-level studies are performed, in order to detect systemic diseases which account for about 20% of CaNL in our series. Cost-to-benefit analysis has shown that the medical procedures for CaNL yield considerable saving in terms of difference between expenditure for drugs and testing and reduction of stone events. However, the current workup cannot be considered exhaustive, because misleading events may hamper the relation between laboratory findings and clinical outcome, and factors other than urine composition have appeared on the scenario of nephrolithiasis. These represent our challenge for the third millennium.

Adult↗
PubMed1999

Expression of the nlsLacz gene in dendritic cells derived from retrovirally transduced peripheral blood CD34+ cells.

BACKGROUND AND OBJECTIVE: Gene transfer and expression of exogenous genetic information coding for an immunogenic protein in antigen presenting cells (APCs) can promote an immune response. This was investigated by retroviral transfer of a marker gene into CD34+ derived APCs. DESIGN AND METHODS: To achieve long term expression of a specific transgene in APCs, G-CSF mobilized peripheral blood CD34+ cell populations were retrovirally transduced with the bacterial nlsLacZ, a marker gene used here as a model, in the presence of IL-3, IL-6, GM-CSF and SCF prior to being induced to differentiate into dendritic and macrophage cells by GM-CSF and TNF-a. RESULTS: Addition of IL-4 was found to induce dendritic differentiation preferentially by inhibiting proliferation and differentiation of the macrophage lineage. As assessed by X-Gal staining, LacZ gene expression was observed in cells from both the dendritic lineage (CD1a+/CD14-) which still exhibits the highest immunostimulatory activity in mixed lymphocyte reaction and from the macrophage lineage (CD1a-/ CD14+). INTERPRETATION AND CONCLUSIONS: This study sets out the possibility of transducing dendritic and macrophage progenitors present in the CD34+ cell population and in using a marker gene such as nlsLacZ to study gene expression in antigen presenting cell compartments.

Antigen Presentation↗
PubMed1999

[Clinical and metabolic features of renal calculi in adults in regard to age of onset].

BACKGROUND: In this paper, the clinical and metabolic patterns of nephrolithiasis in different ages of adulthood are studied. METHODS: Eight-hundred patients observed at the Mauriziano Hospital between 1990 and 1995, were classified into 3 groups, on the basis of age at the onset of disease: A: 20 through 39 years; B: 40 through 59; C: 60 years and over. RESULTS: Calcium-oxalate stones had a lower recurrence in C (19.1%) and B (31.5%) than in A (41.7%). Pure uric acid stones recurred in 18.9% of C, 16.7% of B and 4.3% of A. The prevalence of hypercalciuria was higher in A (50.3%) than in B (35.9%) and C (36%); so did hypocitraturia. Hyperuricuria was lower in A (5%, p < 0.05) than in B (9.4%) and C (10%). Low urine pH (< 5.5) was 13% in A, 21.3% in B, 38% in C. Prevalence of hyperoxaluria was about 14% in all groups. The whole prevalence of secondary forms of stone disease was 13% in A, 12% in B and 30% in C. Differences among groups were mainly due to prevalence of urological abnormalities and urinary tract infection. In patients without metabolic disturbances. urological abnormalities or urinary tract infections altogether, were 4.6% in A; 5.2% in B; 33% in C. Urological approach removed 8% of stones in A, 5.6% in B and 10.2% in C. CONCLUSIONS: Higher morbidity in younger patients could be due to a lower prevalence of easier-passing uric acid stones. The higher occurrence of urological disturbances and struvite stones in the elderly could explain the higher morbidity in this group.

Adult↗