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C Nervi

Publications and source records attributed to C Nervi.

At least 55 records · Page 3Linked to original sources
PubMed1990

Altered protein phosphorylation in murine muscular dystrophy.

Protein phosphorylation has been studied in the dydy murine muscular dystrophy, both in intact muscle cells and in various membrane fractions derived from them. The results obtained showed that several polypeptides were more heavily phosphorylated in dystrophic myotubes in culture as well as in dystrophic muscle fibers isolated from tibialis anterior. In vitro phosphorylation studies revealed that a large polypeptide of apparent molecular weight of 170,000-150,000 was phosphorylated under basal conditions (3 mM EGTA) in dydy microsomal membranes. The phosphorylation of this polypeptide was not stimulated further by cAMP, calmodulin, cGMP or 12-O-tetradecanoylphorbol 13-acetate (TPA). Under no condition was the corresponding polypeptide phosphorylated at an appreciable rate in normal microsomal membranes. An antibody raised against the voltage-dependent calcium channel reacted, in an immunoblot assay, with a polypeptide, present in both normal and dydy microsomes, which had migration characteristics identical to the phosphorylated 170-150 kDa polypeptide after one- or two-dimensional gel electrophoresis. Additional differences were identified in the phosphorylation of smaller polypeptides of microsomal membranes. When sarcolemmal membranes of normal and dydy muscle were phosphorylated in vitro, no major differences were observed. These results show the existence of an alteration of protein phosphorylation in dystrophic muscle cells in vitro and in vivo, leading to abnormal phosphorylation of the voltage-dependent calcium channel. The possible causes and consequences of this alteration are discussed.

Animals↗
PubMed1990

Cefazolin and netilmicin serum levels during and after cardiac surgery with cardiopulmonary bypass.

The kinetics of cefazolin and netilmicin were studied in 10 patients undergoing elective cardiac surgery with hemodilution and cardiopulmonary bypass (CPB). During surgery, but before CPB, cefazolin, 25 mg/kg, and netilmicin, 2 mg/kg, were administered intravenously over 30 minutes. For the 48-hour period following CPB, cefazolin, 25 mg/kg, and netilmicin, 1 mg/kg, were administered intravenously every 8 hours. Initiation of CPB was accompanied by a 28% to 30% decrease in hematocrit and serum antibiotic levels. At the conclusion of surgery, cefazolin and netilmicin serum levels were 41 +/- 12 micrograms/L and 2.5 +/- 0.6 micrograms/mL (mean +/- SD), respectively. During the postoperative period, cefazolin levels were consistently greater than the minimum inhibitory concentration (MIC) for sensitive bacteria (4 micrograms/mL); average netilmicin levels were greater than MIC of sensitive bacteria (2 micrograms/mL) for 2 hours after antibiotic infusion. The netilmicin trough levels were 0.6 +/- 0.5 micrograms/mL. Pharmacokinetic parameters were determined using a model-independent method, and gave the following results during surgery: cefazolin--elimination half-life, 231 minutes, total body clearance, 1.05 mL/kg/min, and steady-state volume of distribution, 243 mL/kg. The values for netilmicin were 249 minutes, 1.18 mL/kg/min, and 353 mL/kg, respectively. Postoperatively there were no significant changes in the disposition of cefazolin, but the elimination half-life of netilmicin was shorter (124 minutes, P less than 0.01) and the total body clearance greater (3.58 mL/kg/min, P less than 0.01) than during surgery.

Adolescent↗
PubMed1990

Positive and negative regulation of proliferation and differentiation in tracheobronchial epithelial cells.

The lung (in particular the bronchial epithelium) is a major site for tumor formation in humans. Environmental factors in conjunction with genetic factors are important determinants in this disease. The acquisition of defects in the control of proliferation and differentiation appears to constitute crucial steps in the transition of a normal to a neoplastic cell. Several factors have been identified that control positively or negatively the proliferation and differentiation of tracheobronchial epithelial cells. These factors include EGF/TGF alpha, TGF beta, insulin/IGFI, KGF, certain cytokines, retinoids, and activators of protein kinase C. Studies with neoplastic cells have identified several protooncogenes and tumor suppressor genes whose gene products are involved in the regulation of cell growth of normal tracheobronchial epithelial cells, and when mutated, lost, or activated, bring about a neoplastic phenotype. Future studies on the precise function of these genes will help to elucidate the mechanisms by which proliferation and differentiation in normal tracheobronchial epithelial cells are regulated and help to understand the molecular changes involved in diseases such as cancer.

Bronchi↗
PubMed1990

Expression of nuclear retinoic acid receptors in wild-type and mutant embryonal carcinoma PCC4.aza1R cells.

Retinoic acid (RA) induces differentiation of murine embryonal carcinoma PCC4.aza1R cells. In this study, the expression of nuclear retinoic acid receptors (RARs) in PCC4.aza1R cells is examined. Analyses of [3H]RA-labeled nuclear extracts prepared from PCC4.aza1R cells by size-exclusion high-performance liquid chromatography demonstrated the presence of a specific RA-binding activity that migrated with a molecular weight of approximately 50,000. More than 95% of this binding activity was associated with the nuclear fraction. In contrast to cytosolic retinoic acid-binding protein, the RARs bound RA analogues of the Ch-series very effectively. Northern blot analyses of total RNA with complementary DNA probes specific for RAR alpha, RAR beta, and RAR gamma showed that PCC4.aza1R cells contain predominantly transcripts encoding RAR alpha and RAR gamma; RAR beta transcripts were undetectable. Treatment of PCC4.aza1R cells with RA increased the levels of RAR beta mRNA in a dose- and time-dependent manner. The RA concentration for half-maximum induction of RAR beta mRNA was 1 nM. An increase in RAR beta mRNA was detectable as early as 2 h after the addition of RA. This increase was not abrogated by cycloheximide, suggesting that protein synthesis is not required for this response. The ability of several retinoids to increase RAR beta mRNA levels in PCC4.aza1R cells correlated well with their binding affinity to the RARs but not with their binding affinity to cytosolic retinoic acid-binding protein. Two mutant cell lines, PCC4(RA)-1 and (RA)-2, which do not undergo differentiation after RA treatment, contained levels of RAR-binding activity very similar to those of the parental cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Oxacillin and tobramycin serum levels during cardiopulmonary bypass.

Antibiotic prophylaxis in cardiac surgery is recommended to combat acquired infections caused by staphylococci and gram-negative bacilli. Prophylaxis seems effective provided blood levels are greater than minimal inhibitory concentrations (MIC). In this study, two doses of antibiotics were compared in 45 patients with normal renal function during cardiopulmonary bypass (CPB). All patients received 50 mg/kg of oxacillin. Group 1 (30 patients) also received 1 mg/kg of tobramycin, while group 2 (15 patients) received 2 mg/kg of tobramycin. Blood samples were taken after the administration of antibiotics, as well as at the onset and conclusion of CPB. Additional samples were taken before and after heparin injection before CPB, and from the arterial and venous cannulae of the bubble oxygenator during CPB. In both groups, oxacillin serum levels were constantly greater than MIC for susceptible bacteria. In group 1, tobramycin levels less than 2 micrograms/mL (MIC for most susceptible bacteria) occurred in four patients before CPB, in 14 patients at the onset of CPB, and in 19 patients at the conclusion of CPB. These low levels were not explained by heparin administration or absorption onto the CPB circuit, but were the result of hemodilution. In group 2, in which all the tobramycin levels were higher than 2 micrograms/mL, serum levels decreased from 9.9 +/- 3.4 (mean +/- SD) to 3.7 +/- 0.7 micrograms/mL throughout the procedure. Plasma creatinine did not change significantly in either group. It is concluded that in patients with normal renal function, doses as high as 50 mg/kg of oxacillin and 2 mg/kg of tobramycin may be necessary before CPB to provide adequate serum levels throughout CPB.

Adult↗
PubMed1989

Identification and characterization of nuclear retinoic acid-binding activity in human myeloblastic leukemia HL-60 cells.

Specific [3H]retinoic acid (RA)-binding sites in nuclear and cytosolic extracts prepared from human myeloblastic leukemia HL-60 cells have been detected by sucrose density gradient sedimentation and size-exclusion high-performance liquid chromatography (HPLC) analyses. This RA-binding activity migrated as a single peak with an apparent molecular weight of 50,000 and greater than 95% of the total binding activity was associated with the nuclear extract. Nuclear extracts prepared from COS-1 cells transfected with an expression vector for the nuclear RA receptors RAR alpha or RAR beta were enriched (20- to 100-fold) with a RA-binding activity that coeluted by size-exclusion HPLC with the putative RAR from HL-60 cells. The HL-60 nuclear receptor exhibited high-affinity binding of RA and its benzoic acid analogs Ch55, Ch30, Ro 13-7410, and SRI 6409-40 and low-affinity binding of retinol, Ro 8-8717, and SRI 5442-60, correlating well with the biological activity of these compounds in HL-60 cells. Saturation binding and Scatchard plot analyses of the binding of RA to the nuclear HL-60 receptor yielded an apparent dissociation constant of approximately 0.46 nM and 1400 +/- 100 receptor sites per cell. Northern blot analyses of poly(A)+ RNA with cDNA probes specific for RAR alpha and RAR beta indicated that HL-60 cells contain predominantly transcripts encoded by the RAR alpha gene. Our results suggest that the observed nuclear RA-binding activity in HL-60 cells might mediate the action of RA in these cells.

Animals↗
PubMed1989

Activity and regulation of calcium-, phospholipid-dependent protein kinase in differentiating chick myogenic cells.

The activity of calcium-, phospholipid-dependent protein kinase (PKc) was measured in (a) total extracts, (b) crude membrane, and (c) cytosolic fractions of chick embryo myogenic cells differentiating in culture. Total PKc activity slowly declines during the course of terminal myogenesis in contrast to the activity of cAMP-dependent protein kinase, which was also measured in the same cells. Myogenic cells at day 1 of culture possess high particulate and low soluble PKc activity. A dramatic decline of particulate PKc activity occurs during myogenic cell differentiation and is accompanied, through day 4, by a striking rise of the soluble activity. The difference in the subcellular distribution of PKc between replicating myoblasts and myotubes is confirmed by phosphorylation studies conducted in intact cells. These studies demonstrate that four polypeptides whose phosphorylation is stimulated by the tumor promoter 12-O-tetradecanoyl phorbol 13-acetate in myotubes, are spontaneously phosphorylated in control myoblasts. Phosphoinositide turnover under basal conditions in [3H]inositol-labeled cells is faster in myoblasts than in myotubes, a finding that may in part explain the different distribution of PKc observed during the course of myogenic differentiation.

Animals↗
PubMed1989

Increased cholesterol sulfate and cholesterol sulfotransferase activity in relation to the multi-step process of differentiation in human epidermal keratinocytes.

In this study the synthesis of cholesterol sulfate is examined in relation to the process of squamous differentiation in normal human epidermal keratinocytes (NHEK) in culture. During the exponential growth phase, NHEK cells exhibit a relatively high colony-forming efficiency and appear undifferentiated on the basis of their morphology and expression of biochemical characteristics. At confluence, the cells undergo terminal differentiation that is characterized by the commitment to terminal cell division (reduction in colony-forming ability) and expression of the differentiated phenotype. An accumulation of cholesterol sulfate accompanies this program of differentiation. This accumulation of cholesterol sulfate parallels the increase in transglutaminase type I activity and the competence to form cross-linked envelopes, whereas it precedes the "spontaneous" formation of cross-linked envelopes. Increased cholesterol sulfotransferase activity appears to account for the increase in cholesterol sulfate. The cholesterol sulfate accumulation, as well as the increase in cholesterol sulfotransferase and transglutaminase activity, are inhibited by retinoids. However, the presence of retinoids does not prevent NHEK cells from undergoing terminal cell division at confluence. Two NHEK cell lines expressing SV40-large T antigen also undergo terminal differentiation at confluence and start to accumulate cholesterol sulfate. Two other, differentiation-defective cell lines do not exhibit an increase in cholesterol sulfate at confluence. These results show that epidermal keratinocytes in culture, like cells in the epidermis, accumulate cholesterol sulfate when undergoing squamous differentiation. This program appears to consist of a retinoid-insensitive step (commitment to terminal cell division) and a retinoid-sensitive step (expression of the squamous differentiated phenotype).

Calcium↗
PubMed1987

Acetylcholine may regulate its own nicotinic receptor-channel through the C-kinase system.

Acetylcholine (ACh)-activated channel properties were examined on an aneural culture of chick embryo myotubes by using patch-clamp techniques. Changes in conductance, open time and closed time were induced by the selective activator of the calcium- and phospholipid-dependent C-kinase (PKc), 12-O-tetradecanoylphorbol-13-acetate (TPA). The action of TPA was mimicked by exogenous phospholipase C and was blocked by the PKc inhibitor, 1-(5-isoquinolinylsulphonyl)-2-methyl-piperazine. In addition to its gating action, ACh was shown to stimulate phosphoinositide turnover and to translocate PKc from the cytosol to the cell membrane. Both these ACh-induced effects were inhibited by curare and not substantially affected by atropine. Bath-applied ACh outside the patch-pipette in the cell-attached patch-clamp mode, had a strong effect on the ACh-activated channels in the patch membrane, in a way that resembled the action of TPA. These findings raise the possibility that ACh regulates its own nicotinic receptors through the C-kinase system.

Acetylcholine↗
PubMed1987

[Diffusion of ceftriaxone in the renal parenchyma].

Diffusion of ceftriaxone in renal parenchyma after IV injection (2 g) was studied in six patients with normal renal function, undergoing nephrectomy. Cortex and medulla of the kidney were studied. Blood samples, tissular fragments and urine were studied for drug concentration using HPLC and microbiologic assay 1, 12 and 24 h after injection. Both methods led to similar results. No difference in drug concentration was found between cortex and medulla. Tissular concentration of ceftriaxone remain higher than MIC for most Enterobacteriaceae strains until 24 h.

Adult↗
PubMed1986

Proliferating and quiescent cells exhibit different subcellular distribution of protein kinase C activity.

The activity of calcium, phospholipid-dependent protein kinase (PKc), which is thought to play an important role in cell proliferation, has been measured in the particulate and soluble fractions of cultured cells, under different proliferative conditions. Our results indicate that proliferating cells display higher PKc activity than quiescent cells. Furthermore, in both normal and transformed cells, PKc is preferentially associated with the particulate fraction when the cells are proliferating, while in mitotically quiescent cells the majority of the enzyme activity is found in the soluble fraction. These data suggest tha PKc activity and subcellular distribution undergo spontaneous changes according to the proliferative state of the cells.

Animals↗
PubMed1985

Acetylcholine stimulates phosphatidylinositol turnover at nicotinic receptors of cultured myotubes.

Acetylcholine treatment of [3H]inositol pre-labelled cultured chick embryo myotubes results in the stimulation of phosphatidylinositol breakdown, as shown by the measurement of inositol-1-phosphate accumulating in the presence of lithium. The described effect is dependent on agonist concentration and incubation time, and is inhibited by tubocurarine and alpha-bungarotoxin. The activation of phosphatidylinositol breakdown by acetylcholine at extrajunctional nicotinic receptors is likely to be involved in the modulation of the functional activity of the receptor.

Acetylcholine↗
PubMed1985

Pilot study of multiple-fraction daily radiotherapy alternating with chemotherapy in patients with stage IV non-oat cell lung cancer.

From March 1982, 31 patients with stage IV non-oat cell lung cancer have been treated. Radiotherapy was given as three 2.00-Gy fractions on Days 1 and 2, 8 and 9, 22 and 23, and 29 and 30, for a total dose of 48 Gy over a 30-32-day treatment period. A three-drug combination of cyclophosphamide (400 mg/m2), doxorubicin (17 mg/m2), and methotrexate (15 mg/m2) was given on Days 3 and 24 and repeated thereafter every 21 days. Three of 31 evaluable patients (10%) achieved objective complete response and 18 of 31 (58%) achieved partial response (ie, regression of 50%-90%), while no change or disease progression was observed in ten of 31 (32%). The overall response rate in our study was 68%, which is a response much higher than other results in extensive disease. However, controlled trials will be necessary to definitively establish the superiority of this regimen to conventional trials. There was a significant shift of performance status towards higher values after treatment: 12 of the 27 patients classified in the 70-80 Karnofsky category before treatment moved to the higher category, 13 remained in the same status, and only two shifted to the worst category, indicating that the treatment had been effective in giving patients a better quality of life during their survival. The median survival was 35 weeks for the entire group of patients and 44 and 15 weeks for the responders and nonresponders, respectively. One of the primary findings of this pilot study was the ability to give one course of 12 Gy of radiation as multiple fractions per day during each of the first 2 weeks of treatment alternated with one course of chemotherapy, with most patients having very mild or no side effects. Giving multiple daily fractions greater than or equal to 4 hours apart permits the delivery of a large amount of irradiation over a short time period (ie, 1-2 days) within the limits of normal tissue toxicity. Increasing the recovery time of radiotherapy by alternation with chemotherapy offers the possibility of increasing the total radiation dose beyond the upper limits now considered feasible by conventional radiation schedules for induction therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1984

Problem of sequence and fractionation in the clinical application of combined heat and radiation.

Tumor control, thermal enhancement, and therapeutic effect have been evaluated in a series of studies on 77 patients with a total of 163 multiple superficial lesions by using different protocols of combined radiotherapy and local external hyperthermia. Local tumor control and recurrence rate were constantly better in lesions treated with combined treatment in comparison with those treated with radiotherapy alone, regardless of treatment schedule. The enhancement of tumor control appeared to be related to both the magnitude of the applied heat and the size of radiation fractions, in that an increase in either produced an increase in tumor control. When tumor and critical normal tissue were heated to the same temperature, the immediate combination of heat and large radiation fractions resulted in a pronounced enhancement of tumor control, but the concomitantly heated normal tissue showed an increased percentage of radiation reaction, resulting in a low therapeutic advantage. By introducing an interval of 4 hr between the two modalities or by delivering few heat fractions during the course of a conventional fractionation radiotherapy, the enhancement of tumor control was lower, but the increase in skin reaction was minimal, resulting in a clearly improved therapeutic effect. When the tumor could be preferentially heated with respect to normal tissue, the immediate combination of the highest hyperthermic treatment and the largest radiation fractions resulted in the best therapeutic advantage, since no increase of skin reaction was observed.

Adenocarcinoma↗
PubMed1983

Non-small-cell lung carcinoma: tumor characterization on the basis of flow cytometrically determined cellular heterogeneity.

Some 150 tumor specimens from 49 patients with non-small-cell carcinoma of the lung (23 epidermoid, 14 adenocarcinoma, 12 large-cell carcinoma) and three with nonneoplastic lung disease were analysed for cellular DNA content by flow cytometry. Monodispersed cells were stained with ethidium bromide and mithramycin. Normal specimens and samples from patients with nonneoplastic disease constantly yielded a single cell population with diploid DNA content. Twenty of 23 epidermoid carcinomas exhibited one or more than one aneuploid subpopulation. Ten of 12 large-cell carcinomas were characterized by one aneuploid clone and 2/12 by two aneuploid clones. Adenocarcinoma exhibited multiclonal cell subpopulations (one to five aneuploid clones). Further information has been obtained on the differential presence of clones in various tumor areas and in infiltrated lymph nodes. These tumors appear characterized by a remarkable degree of cellular heterogeneity. The cytometric ploidy level(s) and the cell population multiclonal structure yield, in comparison with, and in addition to, pathology, indications of possible clinical interest. A correlation between the clonal DNA content and a prognostic parameter such as the tumor mass doubling time has been demonstrated.

Adenocarcinoma↗