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A De Luca

Publications and source records attributed to A De Luca.

At least 199 records · Page 11Linked to original sources
PubMed1996

[Glomerulonephritis in the elderly].

The authors present a clinical analysis of the literature data regarding aged patients affected with glomerulonephritis (GN) and of 115 GN patients aged more than 65 years, biopsied in their own Center. Complications of renal biopsy, including the subclinical ones, were found in 19.1% of old patients compared to 19.2% of younger patients (p = NS), major complications in 5 and 1.4% respectively (p = NS). The most frequent GN was membranous GN (MGN) (27.8%), followed by IgA-GN (12%) and rapidly progressive GN (RPGN), idiopathic (8.6%) or secondary to vasculitis (8.6%). Eighteen out of 32 old MGN patients treated with alternated courses of steroids and immunosuppressive drugs for 6 months were compared to 32 MGN patients aged < 65 years identically treated. Complete remission was observed in 27.7% of cases and partial remission in 38.8% (p = NS). Complications of treatment were similar in the two groups of patients (p = NS). Patients with RPGN were treated with steroids (17 patients) plus immunosuppressive drugs (15 patients) and plasma exchange (13 patients). Systemic symptoms disappeared in 13/14 patients; ANCA became negative in all the 5 patients in whom they were detected; a 50% reduction of serum creatinine was obtained in 12 patients. These patients were compared to a control group of 26 patients aged < 65 years. Amelioration of renal function was evidenced more frequently among old patients with vasculitis (p < 0.05). Complications of treatment were more frequent among old patients with idiopathic RPGN (p < 0.05), but severe in only 1 case. Our data and data from the literature support the opportunity to perform renal biopsy in aged people, because it is as safe as in the younger population and allows a rational basis for treatment of GN. Clinical responses are similar to those of younger patients. Complications of treatment seem to be more frequent in old patients, but can be limited by some technical precautions and careful clinical monitorization.

Age Distribution↗
PubMed1996

The retinoblastoma gene family and its role in proliferation, differentiation and development.

The retinoblastoma gene family is composed of three members: the retinoblastoma gene, one of the most well studied tumor suppressor genes and two related proteins, p107 and pRb2/p130. These three proteins share many structural and functional features and play a fundamental role in growth control. Intense investigation of these proteins has identified a series of similar cell-cycle regulators and transcription factors with which they interact. Although the precise function of the retinoblastoma gene product and its relatives remains unknown, recent data suggests that they play parallel roles in controlling cell cycle progression and promoting cellular differentiation. In this review, we will attempt to clarify some of the molecular mechanisms by which these three related proteins cooperate to control cellular proliferation and differentiation.

Animals↗
PubMed1996

Differential expression of the retinoblastoma gene family members pRb/p105, p107, and pRb2/p130 in lung cancer.

The Rb (retinoblastoma) gene family is composed of three members: the RB gene (one of the best-studied tumor suppressor genes) and two related genes, p107 and pRb2/p130. These three proteins share many structural and functional features and play a fundamental role in growth control. Using immunocytochemical techniques, we evaluated a variety of lung tumor specimens for the expression of this family of proteins and compared protein expression with the histological grading of the tumors and with the expression of the proliferating cell nuclear antigen. These Rb family members displayed distinctive patterns when compared and contrasted using different parameters. The highest percentage of undetectable levels in all of the specimens examined and the tightest inverse correlation (P) with the histological grading and with proliferating cell nuclear antigen expression in the most aggressive tumor types were found for pRb2/p130, which may suggest an important role for this protein in the pathogenesis and progression of lung cancer.

Animals↗
PubMed1995

The cdc-2-related kinase, PISSLRE, is essential for cell growth and acts in G2 phase of the cell cycle.

Mammalian cell cycle progression is regulated by several protein kinases that are activated by cyclically expressed proteins called cyclins. These cyclin-dependent kinases, the prototype of which is the cdc2 mitosis-promoting kinase, are known to phosphorylate substrates the modified status of which is critical for the cell to progress into sequential phases of the cycle. Recently, a new cdc2-related protein kinase has been discovered. PISSLRE, named with respect to its homology to the cdc2 PSTAIRE amino acid domain. Here we report that by using both antisense and dominant-negative mutant constructs of PISSLRE when overexpressed in U2OS cells, a growth suppression is found. Furthermore, the dominant negative forms of PISSLRE halt cell cycle progression in G2-M. Therefore, PISSLRE is essential for cellular proliferation, and its effect is exerted in G2-M. This describes the first evidence since cdc2 of a cdc2-related kinase acting through G2-M.

Amino Acid Sequence↗
PubMed1995

Modulation of retinoblastoma gene in normal adult hematopoiesis: peak expression and functional role in advanced erythroid differentiation.

The retinoblastoma (RB) gene specifies a nuclear phosphoprotein (pRb 105), which is a prototype tumor suppressor inactivated in a variety of human tumors. Recent studies suggest that RB is also involved in embryonic development of murine central nervous and hematopoietic systems. We have investigated RB expression and function in human adult hematopoiesis--i.e., in liquid suspension culture of purified quiescent hematopoietic progenitor cells (HPCs) induced by growth factor stimulus to proliferation and unilinage differentiation/maturation through the erythroid or granulocytic lineage. In the initial HPC differentiation stages, the RB gene is gradually induced at the mRNA and protein level in both erythroid and granulopoietic cultures. In late HPC differentiation and then precursor maturation, RB gene expression is sustained in the erythroid lineage, whereas it is sharply downmodulated in the granulocytic series. Functional studies were performed by treatment of HPC differentiation culture with phosphorothioate antisense oligomer targeting Rb mRNA; coherent with the expression pattern, oligomer treatment of late HPCs causes a dose-dependent and selective inhibition of erythroid colony formation. These observations suggest that the RB gene plays an erythroid- and stage-specific functional role in normal adult hematopoiesis, particularly at the level of late erythroid HPCs.

Adult↗
PubMed1995

Dissection of the genetic programs of p53-mediated G1 growth arrest and apoptosis: blocking p53-induced apoptosis unmasks G1 arrest.

Employing the myeloblastic leukemia M1 cell line, which does not express endogenous p53, and genetically engineered variants, it was recently shown that activation of p53, using a p53 temperature-sensitive mutant transgene (p53ts), resulted in rapid apoptosis that was delayed by high level ectopic expression of bcl-2. In this report, advantage has been taken of these M1 variants to investigate the relationship between p53-mediated G1 arrest and apoptosis. Flow cytometric cell cycle analysis has provided evidence that activation of wild-type (wt) p53 function in M1 cells resulted in the induction of G1 growth arrest; this was clearly seen in the M1p53/bcl-2 cells because of the delay in apoptosis that unmasked p53-induced G1 growth arrest. This finding was further corroborated at the molecular level by analysis of the expression and function of key cell cycle regulatory genes in M1p53 versus M1p53/bcl-2 cells after the activation of wt p53 function; events that take place at early times during the p53-induced G1 arrest occur in both the M1p53 and the M1p53/bcl-2 cells, whereas later events occur only in the M1p53/bcl-2 cells, which undergo delayed apoptosis, thereby allowing the cells to complete G1 arrest. Finally, it was observed that a spectrum of p53 target genes implicated in p53-induced growth suppression and apoptosis were similarly regulated, either induced (gadd45, waf1, mdm2, and bax) or suppressed (c-myc and bcl-2), after activation of wt p53 function in M1p53 and M1p53/bcl-2 cells. Taken together, these findings show that wt p53 can simultaneously induce the genetic programs of both G1 growth arrest and apoptosis within the same cell type, in which the genetic program of cell death can proceed in either G1-arrested (M1p53/bcl-2) or cycling (M1p53) cells. These findings increase our understanding of the functions of p53 as a tumor suppressor and how alterations in these functions could contribute to malignancy.

Animals↗
PubMed1995

Cytokine induction of proliferation and expression of CDC2 and cyclin A in FDC-P1 myeloid hematopoietic progenitor cells: regulation of ubiquitous and cell cycle-dependent histone gene transcription factors.

To evaluate transcriptional mechanisms during cytokine induction of myeloid progenitor cell proliferation, we examined the expression and activity of transcription factors that control cell cycle-dependent histone genes in interleukin-3 (IL-3)-dependent FDC-P1 cells. Histone genes are transcriptionally upregulated in response to a series of cellular regulatory signals that mediate competency for cell cycle progression of the G1/S-phase transition. We therefore focused on factors that are functionally related to activity of the principal cell cycle regulatory element of the histone H4 promoter: CDC2, cyclin A, as well as RB- and IRF-related proteins. Comparisons were made with activities of ubiquitous transcription factors that influence a broad spectrum of promoters independent of proliferation or expression of tissue-specific phenotypic properties. Northern blot analysis indicates that cellular levels of cyclin A and CDC2 mRNAs increase when DNA synthesis and H4 gene expression are initiated, supporting involvement in cell cycle progression. Using gel-shift assays, incorporating factor-specific antibody and oligonucleotide competition controls, we define three sequential period following cytokine stimulation of FDC-P1 cells when selective upregulation of a subset of transcription factors is observed. In the initial period, the levels of SP1 and HiNF-P are moderately elevated; ATF, AP-1, and HiNF-M/IRF-2 are maximal during the second period; while E2F and HiNF-D, which contain cyclin A as a component, predominate during the third period, coinciding with maximal H4 gene expression and DNA synthesis. Differential regulation of H4 gene transcription factors following growth stimulation is consistent with a principal role of histone gene promoter elements in integrating cues from multiple signaling pathways that control cell cycle induction and progression. Regulation of transcription factors controlling histone gene promoter activity within the context of a staged cascade of responsiveness to cyclins and other physiological mediators of proliferation in FDC-P1 cells provides a paradigm for experimentally addressing interdependent cell cycle and cell growth parameters that are operative in hematopoietic stem cells.

Base Sequence↗
PubMed1995

The RB2/p130 gene product is a nuclear protein whose phosphorylation is cell cycle regulated.

The Rb2/p130 protein has been shown to have a high sequence homology with the retinoblastoma gene product (pRb), one of the most well-characterized tumor suppressor genes, and with pRB-related p107, especially in their conserved pocket domains, which display a primary role in the function of these proteins. In this study, we report on the biochemical and immunocytochemical characterization of the Rb2/p130 protein, using a polyclonal antibody developed against its "spacer" region included in the pocket domain of the whole protein. We show that pRb2/p130 is a phosphoprotein located at the nuclear level and that its phosphorylation pathway can be dramatically reduced by phosphatase treatment. Moreover pRb2/p130 with p107, is one of the major targets of the E1A viral oncoprotein-associated kinase activity, showing a phosphorylation pattern which is modulated during the cell cycle, reaching a peak of activation at the onset of S-phase.

Antibodies, Monoclonal↗
PubMed1995

ets-2 regulates cdc2 kinase activity in mammalian cells: coordinated expression of cdc2 and cyclin A.

ets-2 is a member of a family of transcription factors implicated in the regulation of gene expression during cell proliferation, cell differentiation, and development. We report that the ets-2 protein transactivates the promoter of the cdc2 gene which encodes a 34-kDa serine-threonine kinase required for mitotic initiation in mammalian cells. Transactivation occurs via specific interaction with multiple ets binding sites in the 5' flanking region of the gene. In BALB/c3T3 rodent fibroblasts constitutively expressing ets-2 and cultured in either 10 or 0.5% serum, cdc2 expression and its associated histone H1 kinase activity are increased, compared to control cells. Such increased activity correlates with elevated levels of cyclin A but not cyclin B1. Furthermore, ets-2-transfected, but not parental, BALB/c3T3 cells, grow under low serum conditions, albeit at a reduced rate. These data demonstrate that ets-2 plays a direct role in the regulation of cdc2 expression and raise the possibility that ets-2 participates in the coordinated regulation of cdc2 cyclin A expression which is essential for the modulation of cdc2-regulated processes.

3T3 Cells↗
PubMed1995

Stereoselective effects of mexiletine enantiomers on sodium currents and excitability characteristics of adult skeletal muscle fibers.

The effects of the enantiomers of mexiletine were tested on sodium currents of frog skeletal muscle fibers recorded by means of the three vaseline gap voltage clamp method and compared with the effects produced by tocainide enantiomers. The R-(-) mexiletine produced a tonic block of the sodium current, elicited by single depolarizing test pulses from the holding potential of -100 mV to -20 mV, with an IC50 of 43.9 +/- 1 microM, whereas the corresponding S-(+) enantiomer produced the same effects at about twofold higher concentrations. A similar steroselectivity was observed with tocainide enantiomers, but at about 5 fold higher concentrations. Both the R-(-) and S-(+) enantiomers of mexiletine and tocainide produced a further use-dependent block of sodium currents when the test pulse was applied repetitively at a frequency of 2 Hz. The use dependent behavior led to a significant lowering of the IC50 values with respect to the tonic block but the eudismic ratios ([IC50S-(+)]/[IC50R(-)]) and the relative potency between mexiletine and tocainide were maintained. All the tested compounds produced a left shift of the steady state inactivation curves (h infinity), suggesting a high-affinity interaction with the inactivated sodium channels. Again a stronger potency of R-(-) vs. S-(+) enantiomers and of mexiletine vs. tocainide was observed. The excitability characteristics recorded from the semitendinosus muscle by the two microelectrode technique were modified by the tested drugs in agreement with their ability to block sodium current. Thus a concentration-related increase in the threshold current required to elicit an action potential as observed along with a decrease in the amplitude and a shortening of the latency of action potential and a decrease in the firing capability of the membrane. Again the R-(-) isomers were more potent than the S-(+) ones and mexiletine was more effective than tocainide. These data corroborate the presence of a stereospecific site for these drugs on adult skeletal muscle sodium channels. The constant eudismic ratios between the enantiomers during both tonic and use-dependent block suggest that the increase in the apparent affinity of the receptor during state-dependent conformational changes of the channel does not enhance its stereospecificity. The decrease in effective concentration upon high frequency stimulation supports the potential usefulness of low doses of R-(-) mexiletine in the treatment of the abnormal hyperexcitability of the myotonic muscles, with a likely reduction of unwanted side effects.

Action Potentials↗
PubMed1995

Variable efficiency of three primer pairs for the diagnosis of Pneumocystis carinii pneumonia by the polymerase chain reaction.

The efficiency of three different primer pairs, complementary to different Pneumocystis carinii DNA regions, was compared in the polymerase chain reaction (PCR) for the diagnosis of Pneumocystis carinii pneumonia (PCP) on bronchoalveolar fluid (BALF) from patients with AIDS. PCR coupled with dot-blot hybridization (BLOT) using primers and probe from the mitochondrial 23SrDNA region showed the highest sensitivity, with a lower detection limit of 0.5-1 organisms microliter-1. When testing 47 BALF, PCR plus BLOT of the mitochondrial 23SrDNA region showed also the best diagnostic efficiency (97% sensitivity, 100% specificity). Sensitivity was significantly higher than with PCR and BLOT of the 5SrDNA region (81.5% sensitivity; P = 0.025, McNemar test); and of the dehydrofolate reductase (DHFR) gene region (75.6% sensitivity; P = 0.019). Sensitivity was also significantly higher than indirect immunofluorescence (75.8% sensitivity; P = 0.008). Using DHFR primers and probe, specificity was also reduced. The diagnostic sensitivity in clinical specimens paralleled the detection limit in the standard dilutions. The use of repeated DNA sequences of proven specificity as target of PCR amplification favourably influences sensitivity and specificity. This comparative study demonstrates that primer selection plays a significant role in the diagnosis of PCP by PCR.

AIDS-Related Opportunistic Infections↗
PubMed1995

Presumptive clinical criteria versus endoscopy in the diagnosis of Candida esophagitis at various HIV-1 disease stages.

BACKGROUND AND STUDY AIMS: The presumptive diagnosis of Candida esophagitis has been included in the Centers for Disease Control (CDC) case definition for full-blown AIDS since 1987. Endoscopic examination should be reserved for patients showing symptoms despite treatment. The purpose of this study was to assess the degree of diagnostic accuracy of the CDC presumptive clinical criteria and to determine the usefulness of upper digestive endoscopy in the diagnosis of Candida esophagitis in patients infected with HIV-1, with and without a previous AIDS-defining event. PATIENTS AND METHODS: A total of 144 HIV-1 infected patients who had undergone an upper digestive endoscopy were studied retrospectively. To determine the risk and the predictive value of the clinical markers, only the 84 patients without prior antimycotic therapy were included. RESULTS: Of the 84 patients without previous treatment, 34 (41%) had a history of an AIDS-defining illness. Candida esophagitis was found on endoscopy in 11 of the AIDS and 28 of the non-AIDS cases. Oral thrush, either alone (relative risk [R.R.] 9.4; 95% C.I. 2.4-36.4; p < 0.01; positive predictive value [PPV] 82%) or in combination with esophageal symptoms (R.R. 7.4; 95% C.I. 2.5-21.9; p < 0.01; PPV 89%), was a reliable marker of Candida esophagitis only in patients with a previous AIDS-defining event. The diagnostic value of the CDC presumptive pattern was confirmed by a multivariate analysis after controlling for the CD4 cell count (R.R. 9.3; 95% C.I. 2.3-25.3; p < 0.01). On the other hand, in HIV-1 positive patients without a previous AIDS-defining event, the diagnostic accuracy of oral candidiasis, either alone (R.R. 1.4; 95% C.I. 0.8-2.4; p n.s.; PPV 64%) or in combination with esophageal symptoms (R.R. 1.1; 95% C.I. 0.7-1.8; p n.s.; PPV 60%), was too low to allow a reliable diagnosis of Candida esophagitis. CONCLUSIONS: A presumptive diagnosis of Candida esophagitis on the basis of the CDC clinical criteria is a valid diagnostic method only in HIV-1 infected patients with a previous diagnosis of full-blown AIDS. Upper digestive endoscopy should be performed in symptomatic patients with no history of an AIDS-defining illness, especially if the diagnosis of esophageal candidiasis is important for surveillance purposes.

AIDS-Related Opportunistic Infections↗
PubMed1995

Aerosolized pentamidine, cotrimoxazole and dapsone-pyrimethamine for primary prophylaxis of Pneumocystis carinii pneumonia and toxoplasmic encephalitis.

OBJECTIVE: To investigate the efficacy and safety of three regimens for primary prophylaxis of Pneumocystis carinii pneumonia (PCP) and toxoplasmic encephalitis (TE) and to evaluate their effect on survival in patients with HIV infection. DESIGN: Randomized, open label, prospective trial. SETTING: A single Infectious Diseases Department in Italy. PATIENTS: HIV-infected patients (n = 197) with a CD4 count < 200 x 10(6)/l and without previous PCP or TE. INTERVENTIONS: Patients were randomly assigned to receive (1) aerosolized pentamidine (AP; 300 mg monthly), (2) cotrimoxazole (CTX; 160 mg trimethoprim and 800 mg sulfamethoxazole every other day), or (3) dapsone-pyrimethamine (DP; 100 mg weekly dapsone and 25 mg biweekly pyrimethamine). MAIN OUTCOME MEASURES: PCP, TE, death, and drug-limiting toxicity. Considering difference in PCP occurrence the trial was interrupted on June 1992. Observation was prolonged until June 1994 for TE and survival. RESULTS: Intention-to-treat analysis yielded PCP rates of 10.2 per 100 person-years in the AP, 2.0 in the CTX, and 32.1 in the DP group [adjusted relative risk of DP versus CTX: 17.5; 95% confidence interval (CI), 2.2-139.6; P = 0.007]. TE rates in patients with positive Toxoplasma serology were 25.6 per 100 person-years in the AP, 8.9 in the CTX and 9.4 in the DP group. In 'on treatment' analysis, no episode of TE developed in the DP group, and rates were 34.7 per 100 person-years in the AP and 2.5 in the CTX group (AP versus CTX: P = 0.01; AP versus DP: P = 0.004). The adjusted risk of mortality for the DP group was 2.8 times that of the CTX group in the first part of the study (95% CI, 1.1-7.3; P = 0.037), and 1.8 times (95% CI, 1.1-2.9; P = 0.02) in the prolonged follow-up. No significant difference in the occurrence of serious adverse reactions was observed between the three treatment groups. CONCLUSIONS: Intermittent CTX was more effective than low-dose DP and showed a slight but not significant advantage on AP for primary PCP prophylaxis. DP was associated with a shorter survival. Both CTX and DP resulted in a significant reduction in the risk of TE.

AIDS-Related Opportunistic Infections↗
PubMed1995

Evaluation of cerebrospinal fluid EBV-DNA and IL-10 as markers for in vivo diagnosis of AIDS-related primary central nervous system lymphoma.

Acquired immunodeficiency syndrome (AIDS)-related primary central nervous system lymphoma (PCNSL) is almost always associated with the Epstein-Barr virus (EBV), and EBV-DNA in cerebrospinal fluid (CSF) has been indicated as a useful tumour marker for this HIV-related neoplasm. AIDS lymphomas also show an enhanced production of IL-10 which is generally associated with the presence of EBV in lymphoma cells. We performed a prospective study in 19 HIV seropositive patients with brain mass lesions, and in 21 other AIDS patients with or without other neurological disorders, to assess the in vivo diagnostic value of EBV-DNA and of IL-10 levels in the CSF for primary lymphoma of the central nervous system (CNS). EBV-DNA was detected by a nested polymerase chain reaction (PCR) in the CSF from seven of eight patients with PCNSL, diagnosed by brain biopsy (87.5% sensitivity) and in none of the 11 controls with brain mass lesions (100% specificity) and of the other 21 AIDS patients with or without neurological disorders. The only patient with PCNSL without detectable EBV-DNA in the CSF was also negative for EBV-DNA in the lymphoma tissue, whereas the samples of the other seven brain lymphomas were all positive for EBV-DNA by nested PCR. Therefore 100% of patients with an EBV-positive primary CNS lymphoma had detectable EBV-DNA in the CSF. No patient from the control group without PCNSL with EBV-negative CSF developed a lymphoma after a mean follow-up of 157 +/- 173 d. IL-10 levels in the CSF from the patients with PCNSL were not significantly different from those in the other groups of patients with AIDS. Due to uniformly high levels in the CSF from AIDS patients, IL-10 is not a useful diagnostic marker for AIDS-related brain lymphoma. The detection of EBV-DNA from the CSF by nested PCR is an extremely sensitive and specific diagnostic tool for AIDS-related PCNSL and should be further evaluated as a possible alternative in patients from whom brain biopsy is not advisable.

Adult↗
PubMed1995

Genetic variability in different Pneumocystis isolates from man and rats.

To gain further insight into the genetic variability between different isolates of Pneumocystis carinii of rat and human origin, we sequenced three DNA regions from the mitochondrial rRNA gene, the 5S rRNA gene and the dihydrofolate reductase gene (DHFR) of microorganisms isolated from three different immunosuppressed rat sources and from one HIV + patient with P. carinii pneumonia. Some point mutations and deletions were found among rat isolates in two regions (mitochondrial rRNA gene and 5S rRNA gene). Nucleotide sequence variations in these conserved regions support the hypothesis of the existence of several Pneumocystis strains infecting the same host species.

Animals↗
PubMed1995

Potential risk of myopathy by HMG-CoA reductase inhibitors: a comparison of pravastatin and simvastatin effects on membrane electrical properties of rat skeletal muscle fibers.

To get insight into the potential risk of myopathy associated with therapy involving 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, we evaluated in vivo and in vitro the effects of a daily 2 to 3-month treatment with pravastatin (100 mg/kg) and with simvastatin (5, 10 and 50 mg/kg) on the electrical properties of rat skeletal muscle fibers. The electromyographic activity revealed no sign of myopathy during treatment with pravastatin and with simvastatin. At the end of the treatment, the passive and active membrane electrical parameters of the extensor digitorum longus muscles were measured in vitro by computerized two-intracellular-microelectrode technique. A dose-dependent reduction of membrane chloride conductance was recorded in extensor digitorum longus fibers of simvastatin-treated groups, and at 50 mg/kg the reduction of chloride conductance was significant in 6 out of the 7 treated rats. By contrast, none of the pravastatin-treated rats showed significant alteration of chloride conductance. Consequently, the excitability parameters were modified by simvastatin but not by pravastatin treatment, whereas the resting membrane potential was not affected. An increase in potassium conductance, reduced by in vitro application of glybenclamide, was recorded in 30% of the simvastatin-treated rats (50 mg/kg) and in only 15% of the pravastatin-treated rats. Our results suggest that the risk of myopathy is much higher with the lipophilic simvastatin than with the hydrophilic pravastatin and support the hypothesis that the muscle toxicity of HMG-CoA reductase inhibitors is due to an intracellular action mediated by the inhibition of muscle cholesterol synthesis.

Animals↗