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A Porcellini

Publications and source records attributed to A Porcellini.

At least 55 records · Page 3Linked to original sources
PubMed1995

Regulation of 11 beta-hydroxylase cytochrome p450 expression by cholesterol in spontaneously hypertensive rats.

OBJECTIVE: To investigate whether hypercholesterolaemia interferes with the expression of the enzymes involved in steroid biosynthesis in the adrenal cortex. METHODS: Twenty-four 5-week-old male spontaneously hypertensive rats (SHR) were randomly assigned to a high (1%) cholesterol diet (n = 8) or to a matched cholesterol-free diet (n = 8) for 6 weeks. A third group (n = 8) was studied after 2 weeks of washout from the high-cholesterol intake. A cohort of age- and sex-matched normotensive Wistar-Kyoto (WKY) rats (n = 24) underwent the same treatments and was used as a control. RESULTS: In SHR cholesterol feeding reduced urinary sodium excretion (0.8 +/- 0.1 versus 1.4 +/- 0.1 mmol/24 h in the cholesterol-free group), increased plasma aldosterone levels (299 +/- 60 versus 154 +/- 24) and reduced plasma corticosterone levels (142 +/- 21 versus 278 +/- 35 ng/ml). Those responses were associated with a reduction of 11 beta-hydroxylase cytochrome P450 messenger RNA (mRNA) in the adrenal cortex (-52.3 +/- 3.4%) whereas aldosterone synthase mRNA remained unchanged. That effect and the changes in electrolyte excretion and steroid levels were no longer detectable after withdrawal of the diet. In WKY rats high-cholesterol diet induced no significant changes in urinary electrolyte excretion, steroid levels and expression of 11 beta-hydroxylase cytochrome P450 and aldosterone synthase in the adrenals. CONCLUSIONS: The present results indicate that in SHR hypercholesterolaemia selectively interferes with the adrenal steroid biosynthetic pathway by reducing the expression of 11 beta-hydroxylase, leading to accumulation of mineralocorticoids and sodium retention.

Adrenal Cortex↗
PubMed1995

Regulation of aldosterone biosynthesis by adrenal renin is mediated through AT1 receptors in renin transgenic rats.

The transgenic (TG) rat (mREN2)27 is characterized by overexpression of the additional mouse Ren-2d gene in the adrenal cortex with marked suppression of renal renin. We have previously shown that in salt-depleted TG rats enhanced activation of mineralocorticoid biosynthesis is associated with selective stimulation of adrenal renin. To investigate whether the local renin-angiotensin system regulates aldosterone biosynthesis in the adrenal cortex of TG rats, we studied the effects of the AT1-angiotensin subtype receptor antagonist DuP 753 on aldosterone production in 5-week-old TG rats during salt restriction. All the rats (n = 56) were shifted from regular chow to a diet containing only 0.04% NaCl for 1 week. The AT1-receptor antagonist DuP 753 (10 mg/kg per day in drinking water) was administered to 27 of these rats during low-salt diet. Subgroups of rats were killed at 0,4, and 7 days. Low-salt diet increased both adrenal renin activity (from 31 +/- 3 to 77 +/- 4 and 85 +/- 2 ng angiotensin I.h-1.mg protein-1 at 4 and 7 days, respectively; P < .001) and mRNA (by 68.4 +/- 10% and 80 +/- 17% from baseline, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMed1995

Absence of D2S dopamine receptor in the prolactin-secreting MMQ pituitary clone: characterization of a wild D2L receptor coupled to native transduction mechanisms.

We used the PCR amplification technique in an attempt to characterize further the dopamine D2L receptor expressed in the prolactin-secreting pituitary MMQ cell clone, derived from the prolactin- and ACTH-secreting Buffalo rat 7315 alpha pituitary tumour. By semiquantitative PCR amplification we were unable to detect the mRNA encoding the D2S receptor isoform, which derives from the well-known process of alternative splicing, producing two D2 receptor subtypes (D2L and D2S) in such tissues as the anterior pituitary and the corpus striatum. Although the pharmacology of the D2 receptor has been established in many studies on both native receptors and transfected receptor isoforms, because of the lack of tissues naturally expressing only one receptor isoform, MMQ cells represent the first example of cells uniquely or prevalently expressing only the D2L receptor, conceivably coupled to its native transduction mechanisms. These considerations prompted us to evaluate the pharmacology and the second messenger systems known to be modulated by dopamine. Scatchard analysis of [3H]spiperone binding resulted in a linear plot, consistent with the existence of a single class of binding sites, with a Kd of 0.055 +/- 0.002 nM and a Bmax of 27 +/- 3.5 fmol/mg protein. Competition experiments confirmed the GTP-dependence and the order of potency for agonist and antagonist ligands consistent with binding to a D2 receptor. The inhibitory effects of dopamine on adenylyl cyclase activity, inositol phosphate production and intracellular free calcium concentrations, the latter presumably via the opening of K+ channels, and prolactin secretion, as well as the reversal of the effect by the D2-selective antagonist (-)sulpiride and pretreatment with pertussis toxin, are consistent with the known biological actions of dopamine at D2 receptors. Based on our observations, the MMQ cell line can be considered a useful tool for investigating ligand-receptor interactions to develop new selective dopaminergic D2L ligands for the therapy of dopamine-related disorders such as schizophrenia, depression, Parkinson's disease and drug addiction.

Adenylyl Cyclases↗
PubMed1994

The DNA sequence encompassing the transcription start site of a TATA-less promoter contains enough information to drive neuron-specific transcription.

The FE65 gene encodes a nuclear protein of unknown function that is expressed in several areas of the rat nervous system during development and in the adult animal, particularly in somatic and visceral ganglia. FE65 mRNA is abundant in neuronal cell lines, whereas it is barely detectable in non-neuronal cells. We identified the two transcription start sites of the FE65 gene and we isolated the rat genomic fragment containing one of these two transcriptional start sites. We demonstrate that this fragment contains a promoter able to direct an efficient transcription of a reporter gene in PC12 cells and in NTERA2 cells upon their differentiation with retinoic acid, whereas it functions poorly in non-neuronal cells, such as Rat2 fibroblasts and BRL hepatocytes. This promoter is composed of two regions. The first includes a cis-element whose removal greatly decreases the transcriptional efficiency in all cells examined and which forms similar complexes with proteins from PC12 and Rat2 cells. This cis-element binds Sp1 or another GC-binding factor. The second cis-element encompasses the transcription start site and is still able to direct transcription only in neuronal cells. The DNA-protein complexes formed by this cis-element in neuronal cells differ from those formed in non-neuronal cells. The analysis of point mutations in this region indicates that the proteins that bind to this cis-element interact with both overlapping and distinct nucleotide sequences.

Amino Acid Sequence↗
PubMed1994

PCR analysis of the H ferritin multigene family reveals the existence of two classes of processed pseudogenes.

The human gene coding for the apoferritin H subunit belongs to a complex multigene family constituted by the expressed gene and by an undefined number of pseudogenes. We have used a strategy based on PCR to amplify specifically the H pseudogenes from a sample of human genomic DNA. With this approach, three new H pseudogenes have been cloned and characterized by DNA sequence analysis. In addition, we have identified a new type of pseudogene, the size of which (700 bp) is caused by multiple detection events in the putative coding region.

Base Sequence↗
PubMed1994

MACOP-B versus ProMACE-MOPP in the treatment of advanced diffuse non-Hodgkin's lymphoma: results of a prospective randomized trial by the non-Hodgkin's Lymphoma Cooperative Study Group.

PURPOSE: The aim of our study was to compare in a multicentric randomized trial two regimens widely used in the treatment of advanced-stage intermediate- to high-grade non-Hodgkin's lymphoma and to assess whether a third-generation regimen (methotrexate with leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin [MACOP-B]) was superior to a second-generation regimen (procarbazine, methotrexate with leucovorin, doxorubicin, cyclophosphamide, and etoposide [ProMACE-MOPP]). PATIENTS AND METHODS: Between January 1987 and August 1991, 221 patients with diffuse intermediate- to high-grade non-Hodgkin's lymphoma (Working Formulation groups F, G, H, and K), stage II bulky (> 10 cm), III, or IV, were randomized by the Non-Hodgkin's Lymphoma Cooperative Study Group (NHLCSG) to receive ProMACE-MOPP for six cycles or MACOP-B for 12 weeks. Survival, progression-free survival, and disease-free survival were determined, and multivariate analysis of prognostic factors was performed. RESULTS: In the two groups of patients, there was no significant difference in terms of complete remission (CR) rate (49.1% with ProMACE-MOPP and 52.3% with MACOP-B), 3-year overall survival rate (45.2% with PROMACE-MOPP and 52.3% with MACOP-B), and 3-year progression-free survival rate (36.4% with ProMACE-MOPP and 36.1% with MACOP-B). In terms of toxicity, no significantly greater toxicity occurred in either arm. Overall toxicity was acceptable. The most frequent side effects were grade II through IV leukopenia, infection, mucositis, and anemia. Treatment-related deaths were equally distributed. CONCLUSION: No significant differences in terms of efficacy and/or toxicity between ProMACE-MOPP and MACOP-B are evident. These results are consistent with recent randomized trials showing that the new-generation aggressive regimens are no better than previous ones.

Adolescent↗
PubMed1994

Novel mutations of thyrotropin receptor gene in thyroid hyperfunctioning adenomas. Rapid identification by fine needle aspiration biopsy.

Hyperfunctioning thyroid adenomas are clonal neoplasms with the intrinsic capacity of growing and differentiate independently of thyroid-stimulating hormone (TSH). We analysed the mRNA encoding thyrotropin receptor of 11 adenomas obtained by fine needle aspiration biopsy (FNAB) and found 7 mutants all located in three aminoacids clustered in the sixth transmembrane domain of the receptor. These mutations were somatic and specifically present in the tumour tissue. DNA sequence revealed that 80 to 90% of the mutations can be rapidly screened and identified by restriction enzyme analysis of the amplified cDNA obtained from the FNABs. The mutation Thr->Ile was introduced in the wild type receptor and expressed in mouse fibroblasts. These cells constitutively activate the transcription of a reporter gene under the control of cyclic AMP responsive element.

Adenoma↗
PubMed1994

Limiting dilution analysis of a novel tripeptide anticancer agent Ambamustine (PTT-119): effect on K-562, CCRF-SB and multidrug resistant LoVo-Dk cell lines.

Cell suspensions of normal human bone marrow were mixed with human acute lymphoblastic or myelogenous leukemic cells of the CCRF-SB or K-562 lines. After incubating the cell mixtures in vitro with different dose levels of Ambamustine (PTT-119), a quantity of 10(4) treated cells were dispensed into microculture plates, and graded cell numbers of the lines used to contaminate the normal marrow were added. Limiting dilution analysis (LDA) was used to estimate the frequency of leukemic cells persisting after treatment. Incubation with 50 micrograms/mL of PTT-119 produced a total elimination of K-562 acute myelogenous blasts, whereas nearly 0.17 and 0.27 leukemic cells were still present in the cell mixtures after treatment with 5 and 25 micrograms/mL, respectively. When normal bone marrow was contaminated with CCRF-SB lymphoblastic cells, incubation with either 50 or 25 micrograms/mL of PTT-119 produced a complete clearing of leukemic cells, whereas with 5 micrograms/mL the leukemic cells in each well were 0.18. When PTT-119 was incubated with LoVo-DX, a colon cancer cell line which expresses the pleiotropic drug resistance MDR phenotype, virtually complete inhibition of clonogenic colonies was observed with as little as 5 micrograms/mL. This suggests that PTT-119 could be used in clinical trials as a non-cross-resistant agent in multidrug protocol.

Antineoplastic Agents↗
PubMed1994

The blockage of the human transferrin receptor by a monoclonal antibody, EA.3, induces growth inhibition in leukemia cell lines.

In our program to produce monoclonal antibodies against hemopoietic functional antigens we have obtained an hybridoma cell line EA.3 reacting with human transferrin receptor. This monoclonal antibody is an IgM that displays "in vitro" antiproliferative activity against leukemic cells due to its competition with transferrin on the receptor. Cell cytotoxicity was demonstrated either with the blockage of BrdU incorporation in HL-60 cells and with leukemic CFU inhibition. In contrast, K562 cells were insensitive to the blockage of the transferrin receptor induced by this MAb.

Antibodies, Monoclonal↗
PubMed1993

Expression of thyrotropin-receptor mRNA in healthy and Graves' disease retro-orbital tissue.

It is not clear whether the ophthalmopathy present in Graves' disease is related to autoimmune reactions to common thyroid/orbit components or is due to specific ocular antigens unrelated to the thyroid. In Graves' disease, serum antibodies to the thyrotropin receptor (TSH-R) can stimulate thyroid function, but no link between the TSH-R and ocular tissues has been found. We have shown, by polymerase chain reaction amplification of specific cDNA, that mature TSH-R mRNA is expressed in the retro-orbital tissue of both healthy subjects and patients with Graves' disease. Of other tissues and cells tested (fibroblasts, lymphocytes, muscle, and thyroid), only thyroid tissue expressed the TSH-R mRNA.

Base Sequence↗
PubMed1993

Thyroid-stimulating hormone-regulated growth and cell cycle distribution of thyroid cells involve type I isozyme of cyclic AMP-dependent protein kinase.

Optimal growth and differentiation of normal rat thyroid FRTL5 cells depend strictly on the presence of thyroid-stimulating hormone (TSH). FRTL5 cells deprived of TSH cease dividing and become quiescent. Addition of TSH to quiescent cells, which activates the cyclic AMP-mediated pathway, is sufficient to stimulate cell entry into S phase of the cell cycle. We have previously shown that the differential expression of the two isozymes, type I and type II, of the cyclic AMP-dependent protein kinase (PKA) correlates with cell growth and differentiation of several rodent and human cell lines. We have studied the role of PKA in the TSH-regulated growth and cell cycle distribution of FRTL5 cells. Upon addition of TSH to FRTL5 cells deprived of hormone, a rapid induction of RI alpha mRNA species occurred within 30 min after treatment, reaching the levels of proliferating FRTL5 cells at 12 h. RII alpha mRNA levels slightly increased after TSH addition, whereas C alpha mRNA levels did not show major changes. Photoaffinity labeling of PKA receptor proteins showed that addition of TSH to quiescent FRTL5 cells induced a progressive increase in RI alpha levels starting at 6 h after stimulation, whereas RII alpha receptor levels increased only slightly. When FRTL5 cells were treated with an antisense oligodeoxynucleotide targeted against the RI alpha regulatory subunit, their growth was arrested, whereas an antisense against the RII alpha regulatory subunit produced only a mild growth inhibition. Moreover, exposure to the antisense RI alpha oligomer resulted in accumulation of cells in the G0-G1 compartment, as during TSH deprivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

NIDDM associated with mutation in tyrosine kinase domain of insulin receptor gene.

A population of 103 patients with non-insulin-dependent diabetes mellitus (NIDDM) was screened for mutations in the tyrosine kinase domain of the insulin receptor gene. Patient genomic DNAs corresponding to exons 17-21 of the insulin receptor gene have been amplified by polymerase chain reaction and analyzed by denaturing gradient gel electrophoresis (DGGE). One patient was identified with an altered pattern of mobility of exon 20 in the DGGE assay. Direct sequence of amplified DNA showed a single nucleotide substitution in the codon 1152 (CGG-- greater than CAG), resulting in the replacement of Arg with Gln. Two bands appeared in the sequence of exon 20 of the insulin receptor (nucleotide position 3584), indicating that this patient was heterozygous for the mutation. Insulin binding to intact erythrocytes from the patient was in the normal range. Although autophosphorylation of the purified insulin receptor also seemed normal, its kinase activity toward the exogenous substrate poly Glu:Tyr (4:1) was undetectable. This mutation may impair insulin receptor kinase and contribute to insulin resistance in this patient.

Alleles↗
PubMed1991

Autologous bone marrow transplantation for advanced stage adult lymphoblastic lymphoma in first complete remission. Report of the Non-Hodgkin's Lymphoma Cooperative Study Group (NHLCSG).

Thirty-six successive adult patients with lymphoblastic lymphoma entered a study of sequential chemotherapy consisting of an intensive LSA2-L2-type protocol to induce first complete remission. Eighteen patients in first CR (median age 22 years, range 15-51), underwent autologous bone marrow transplantation after receiving a conditioning regimen consisting of cyclophosphamide and total body irradiation. Of these 18 patients, 2 were in stage III and 16 in stage IV; 15 showed mediastinal and 9 bone marrow involvement at diagnosis. The transplant procedure was well tolerated and no treatment-induced deaths occurred. At this time, 14 out of 18 patients are alive and well between 1 and 60 months post transplant (median follow-up time 46 months) with an actuarial disease-free survival of 74%. This phase II study suggests that high-dose chemo-radiotherapy followed by autologous bone marrow transplantation may improve long-term disease-free survival in advanced stage adult lymphoblastic lymphoma.

Adolescent↗
PubMed1991

Randomized study of chlorambucil (CB) compared to interferon (alfa-2b) combined with CB in low-grade non-Hodgkin's lymphoma: an interim report of a randomized study. Non-Hodgkin's Lymphoma Cooperative Study Group.

Alpha interferon has shown initial promise in the treatment of low-grade non-Hodgkin's lymphoma (NHL), especially with the nodular form of the disease. The present study enrolled 70 NHL patients who received either chlorambucil (CB; 10 mg/day) or CB plus interferon alfa-2b (5 million units (MU)/m2 subcutaneously three times a week). Among 63 evaluable patients, similar response rates (62.1% and 64.7% respectively) were recorded for the treatment arms. In patients receiving no maintenance therapy, those who received interferon alfa-2b during the induction phase showed a favourable trend in terms of incidence of relapse compared to those who had received chlorambucil alone. During maintenance therapy with interferon alfa-2b, no significant differences in the occurrence of relapse have yet been seen compared to patients on no maintenance therapy. A longer observation period is needed to make a definitive conclusion about the usefulness of interferon maintenance therapy and to evaluate further the effects of the combined schedule of chlorambucil and interferon induction on the duration of remission.

Adult↗
PubMed1991

ProMACE-MOPP vs MACOP-B in high grade non-Hodgkin's lymphomas: a randomised study in a multicenter cooperative study group (NHLCSG).

From January '85 to April '87, 81 patients (pts) with diffuse intermediate and high-grade non-Hodgkin's lymphomas were treated with the ProMace/MOPP protocol in a large Italian Cooperative Study Group (NHLCSG). Criteria for entry into the study included: no prior therapy, stage III-IV or stage II with bulky disease and/or B-symptoms, age below 65. 79 pts were evaluable for response. Almost all pts received six courses of chemotherapy, plus radiotherapy on bulky disease. 53 pts (67%) achieved complete remission (CR), 7 (9%) partial remission (PR), 4 (5%) were considered stable disease (SD) and 15 (19%) progression disease (PD) with 5 of them died early during treatment. The actuarial overall survival (OS) and disease free survival (DFS) are respectively 54% at 61 mos and 62% at 41 mos. The median follow-up from the end of therapy is 56 mos (range 40-68). Until now 20 pts (38%) relapsed on a median time of 8 mos (range 2-21) from CR. These data allowed to us to consider this regimen as effective as the third generation protocols also taking into account the multicenter basis of this study. With the aim to evaluate the impact of the third generation regimen on the outcome of these pts, a randomized study has been performed comparing ProMACE-MOPP with the third generation regimens MACOP-B. Therefore, from 1988 up to now, 206 pts with similar clinical and histological characteristics, have been enrolled in the two arms. No differences in terms of CR and DFS have been registered between the two treatments, with roughly the same toxicity. An analysis of prognostic factors in the larger series of pts treated with ProMACE-MOPP in the first and in the second study (167 pts) was performed. On these basis it seems reasonable that our next step would be to candidate these poor prognosis pts to a new therapeutic strategy which included the use of ABMT and/or PBSC transplantation as first line.

Adult↗