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Biomedical subjects

R Metz

Publications and source records attributed to R Metz.

At least 37 records · Page 2Linked to original sources
PubMed1994

C/EBP is an immediate-early gene required for the consolidation of long-term facilitation in Aplysia.

The consolidation of long-term memory requires protein and mRNA synthesis. A similar requirement has been demonstrated for learning-related synaptic plasticity in the gill-withdrawal reflex of Aplysia. The monosynaptic component of this reflex can be reconstituted in vitro, where it undergoes both short- and long-term increases in synaptic strength in response to serotonin (5-HT), a neurotransmitter released during behavioral sensitization, a simple form of learning. As with sensitization, the long-term synaptic modification is characterized by a brief consolidation period during which gene expression is required. We find that during this phase, the transcription factor Aplysia CCAAT enhancer-binding protein (ApC/EBP) is induced rapidly by 5-HT and by cAMP, even in the presence of protein synthesis inhibitors. Blocking the function of ApC/EBP blocks long-term facilitation selectively without affecting the short-term process. These data indicate that cAMP-inducible immediate-early genes have an essential role in the consolidation of stable long-term synaptic plasticity in Aplysia.

Amino Acid Sequence↗
PubMed1994

c-Fos-induced activation of a TATA-box-containing promoter involves direct contact with TATA-box-binding protein.

Transcriptional activation in eukaryotes involves protein-protein interactions between regulatory transcription factors and components of the basal transcription machinery. Here we show that c-Fos, but not a related protein, Fra-1, can bind the TATA-box-binding protein (TBP) both in vitro and in vivo and that c-Fos can also interact with the transcription factor IID complex. High-affinity binding to TBP requires c-Fos activation modules which cooperate to activate transcription. One of these activation modules contains a TBP-binding motif (TBM) which was identified through its homology to TBP-binding viral activators. This motif is required for transcriptional activation, as well as TBP binding. Domain swap experiments indicate that a domain containing the TBM can confer TBP binding on Fra-1 both in vitro and in vivo. In vivo activation experiments indicate that a GAL4-Fos fusion can activate a promoter bearing a GAL4 site linked to a TATA box but that this activity does not occur at high concentrations of GAL4-Fos. This inhibition (squelching) of c-Fos activity is relieved by the presence of excess TBP, indicating that TBP is a direct functional target of c-Fos. Removing the TBM from c-Fos severely abrogates activation of a promoter containing a TATA box but does not affect activation of a promoter driven only by an initiator element. Collectively, these results suggest that c-Fos is able to activate via two distinct mechanisms, only one of which requires contact with TBP. Since TBP binding is not exhibited by Fra-1, TBP-mediated activation may be one characteristic that discriminates the function of Fos-related proteins.

Adenovirus E1A Proteins↗
PubMed1994

Regulation of Fra-1 and Fra-2 phosphorylation differs during the cell cycle of fibroblasts and phosphorylation in vitro by MAP kinase affects DNA binding activity.

The Fos family of transcription factors, c-Fos, FosB, Fra-1 and Fra-2, are rapidly induced in quiescent fibroblasts following serum or growth factor stimulation. The Fos proteins show distinct patterns of expression during cell growth with only Fra-1 and Fra-2 maintained at significant levels in growing cells, suggesting that the different family members direct unique functions for cell growth. Post-translational modification of Fos proteins has been observed following serum stimulation, which may allow an additional level of regulation. Our studies show that the synthesis and post-translational modification of Fra-1 and Fra-2 in Swiss 3T3 cells is serum-dependent during G1 following the transition from G0 and during asynchronous growth but is serum-independent during S phase and mitosis. Post-translational modification of Fra-1 and Fra-2 causes a significant shift in their gel mobility which is eliminated by alkaline phosphatase treatment. Several kinases can phosphorylate Fra-1 and Fra-2 in vitro, including cAMP-dependent kinase (PKA), protein kinase C (PKC), cyclin-dependent kinase 1-cdc2 (cdc2), and mitogen activated protein (MAP) kinase. From these, MAP kinase is the only one that causes a shift in gel mobility similar to that observed in vivo. One dimensional phosphopeptide maps of Fra-1 and Fra-2 phosphorylated by MAP kinase in vitro are similar to those of in vivo labeled Fra-1 and Fra-2, suggesting that MAP kinase may also phosphorylate Fra-1 and Fra-2 in vivo. We have also determined that phosphorylation of Fra-1 and Fra-2 by MAP kinase increases their DNA binding activity.

3T3 Cells↗
PubMed1993

Phase II study of pirarubicin (THP) in patients with cervical, endometrial and ovarian cancer: study of the Clinical Screening Group of the European Organization for Research and Treatment of Cancer (EORTC).

From 1986 to 1990, a multicentric phase II study was conducted with pirarubicin, a new semi-synthetic anthracyclin[4'-O-tetrahydropyranyl-adriamycin (THP)]. 87 patients with advanced gynaecological cancers were treated: epidermoid cervical carcinoma (n = 31), adenocarcinoma of the endometrium (n = 28) and ovarian adenocarcinoma (n = 28). THP was administered by short intravenous infusion, for 3 consecutive days, every 3 weeks. The initial dose of THP was 25 mg/m2 day (25% of patients) which was then reduced to 20 mg/m2 day. The average number of courses was 3.7 (range 1-10). The cumulative THP dose was 180 mg/m2 (range 56-594) in cervix and endometrial tumours and 121 mg/m2 (range 58-425) in ovarian tumours. Myelosuppression was the major observed toxicity with grade 3-4 leukopenia and thrombocytopenia in 62 and 19% of the patients, respectively. Severe general complications occurred in 6% of the patients with three fatalities due to infections. Gastro-intestinal side-effects were frequent and usually mild (7% of grade 3 vomiting). 48% of the patients showed alopecia, which was complete in 9 cases (10%). 3 patients experienced cardiac events. No significant antitumoral activity was observed in patients who had failed to respond to previous chemotherapy. Promising antitumoral activity was noticed in untreated cervico-uterine carcinomas with 19% partial responses and 12% complete responses (CR). THP activity was lower in endometrial carcinomas (9.5% CR). Results were found to be negligible in ovarian cancer patients, most of them being refractory to previous chemotherapy containing an anthracyclin compound. On the basis of these results, the definite role of THP in gynaecological cancers deserves to be studied in more favourable programmes (e.g. in combined protocols as first-line chemotherapy).

Adenocarcinoma↗
PubMed1993

Structure, mapping, and expression of erp, a growth factor-inducible gene encoding a nontransmembrane protein tyrosine phosphatase, and effect of ERP on cell growth.

We have characterized a growth factor-inducible gene, erp, and demonstrated that it encodes a 367-amino-acid nontransmembrane tyrosine phosphatase protein with significant similarity to the vaccinia virus H1 protein. Immunoprecipitation analyses show that the erp protein, ERP, is rapidly induced following serum stimulation of quiescent fibroblasts. ERP has been expressed as a fusion protein with glutathione S-transferase and shown to have tyrosine as well as serine protein phosphatase activity. The enzymatic activity of ERP depends on the presence of reducing agents such as dithiothreitol, and its tyrosine phosphatase activity is inhibited by sodium vanadate, a potent inhibitor of protein tyrosine phosphatases. The number of stable NIH 3T3 clones obtained after transfection with a vector expressing the complete ERP protein is reduced more than 90% compared with that after transfection with a vector expressing a mutated inactive ERP protein. The remaining ERP-expressing clones present a significant increase in the proportion of bi- and multinucleated cells and a decrease in proliferation rate. Studies on the genomic structure reveal that the erp transcription unit is 2.8 kbp long and split into four exons. The erp gene maps to the 17A2-17C region of the murine genome. Our results demonstrate that the protein product of the immediate-early gene erp has a negative effect on cell proliferation.

3T3 Cells↗
PubMed1992

New, high-sensitivity high-performance liquid chromatographic method for the determination of acyclovir in human plasma, using fluorometric detection.

A high-performance liquid chromatographic method for the determination of acyclovir in human plasma has been developed. It is the first published chromatographic method capable of determining acyclovir in plasma with sufficient sensitivity and for sufficiently long periods of time following oral administration of a standard dose of acyclovir during pharmacokinetic investigations. Following precipitations of the proteins with perchloric acid, the sample is chromatographed with a strongly acidic mobile phase on a reversed-phase column, and is then subjected to fluorometric detection (excitation 260 nm, emission 375 nm). The determination limit is 6-10 ng/ml human plasma. The calibration is linear in the range 10-12,400 ng/ml plasma, with the coefficients of variation less than 8%. The absolute recovery rate is between 102 and 113%. This method has already been used to analyse several thousand plasma samples.

Acyclovir↗
PubMed1991

Tetracosactrin vs. methylprednisolone in the prevention of emesis in patients receiving FEC regimen for breast cancer.

0.5 mg tetracosactrin is considered to be equivalent to 40 mg methylprednisolone with regard to the induced cortisol secretion. 97 female breast cancer patients who received their first two FEC courses (epirubicin 50-75 mg/m2, 5-fluorouracil 500 mg/m2, cyclophosphamide 500 mg/m2) entered this randomised crossover study (76 had previously received an adjuvant treatment); tetracosactrin was administered intramuscularly and methylprednisolone intravenously immediately before chemotherapy administration. The tolerability was evaluated using a diary card during 5 days and patients were asked for their preference at the end of the two cycles. There was no difference either for vomiting (dry heaves were included) or nausea between the two treatments (the analysis was performed on day 1, the worse day of days 2 and 3 and the worse day of days 4 and 5). At day 1, 49% of the patients experienced no or mild nausea after tetracosactrin and 62% after methylprednisolone (not significant) (first period analysis); a complete control of vomiting (including dry heaves) was observed in 49% of the patients after tetracosactrin and 53% after methylprednisolone (not significant). No difference was observed between patients with or without previous chemotherapy. However, slightly more patients preferred tetracosactrin (P = 0.048).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

cAMP stimulates the C/EBP-related transcription factor rNFIL-6 to trans-locate to the nucleus and induce c-fos transcription.

The c-fos serum response element (SRE) is a multifunctional regulatory region of the c-fos promoter that responds to a variety of inducers. Recently, we have demonstrated that the SRE binds the C/EBP-related transcription factor rat NFIL-6 (rNFIL-6). In this study we show that rNFIL-6 is regulated by the cAMP second messenger pathway in the rat pheochromocytoma PC12 cell line. Following forskolin treatment, rNFIL-6 binding to the SRE is increased, and the factor becomes phosphorylated and undergoes a trans-location to the nucleus. In transient cotransfection assays, rNFIL-6 is capable of trans-activating the c-fos promoter in a manner dependent on the SRE. These data show that rNFIL-6 undergoes a novel activation in which cAMP-induced nuclear trans-location allows rNFIL-6 to bind to the SRE and contribute to c-fos activation. We propose that rNFIL-6 is an additional regulatory component of the c-fos gene, which provides cAMP responsiveness to the multifunctional SRE.

Animals↗
PubMed1991

The helix-loop-helix protein rE12 and the C/EBP-related factor rNFIL-6 bind to neighboring sites within the c-fos serum response element.

We show that members of two major families of transcription factors, the helix-loop-helix and C/EBP families, interact with the c-fos serum response element (SRE). Two cDNA clones encoding SRE binding factors (clones 9 and 21) were isolated by the direct screening of a PC12 lambda gt11 cDNA library using SRE oligonucleotide sequences as probes. Clone 9 encodes the rat homolog of the human HLH transcription factor, E12 (called here rE12). Clone 21 encodes a b-zip domain polypeptide that is related to the liver transcription factor C/EBP, and is homologous to the human NFIL-6 transcription factor (called here rNFIL-6). Using in vitro-translated products we show that rNFIL-6 recognizes a 'CCAATT' motif which overlaps the c-fos dyad symmetry element (DSE), the binding site for serum regulatory factor (SRF). Factor rE12 binds to an E-box enhancer sequence, 'CATCTG', immediately adjacent to the rNFIL-6 site, within the SRE. Antibodies specific to rE12 and rNFIL-6 disrupt nucleoprotein complexes with these DNA-binding sites, confirming the interaction of native in vivo factors. We present evidence that rNFIL-6 and SRF binding are mutually exclusive, consistent with the overlap of their binding sites. The demonstration that rE12 and rNFIL-6 bind to the SRE at sites adjacent to the major c-fos regulatory element, the DSE, raises the possibility that helix-loop-helix and C/EBP families regulate the SRE and provide a new basis for the multifunctional properties of the SRE, including possible tissue specificity of expression.

Amino Acid Sequence↗
PubMed1990

Phase II study of oral idarubicin in elderly patients with advanced breast cancer.

Thirty-one elderly patients with measurable advanced breast cancer entered this phase II study. A dose of 15 mg/m2/day of Idarubicin (IDA) for 3 consecutive days every 3 weeks was given orally. Mean total cumulative dose of IDA received was 175 mg/m2 (range: 45-475 mg/m2). Mean number of cycles given was four (range: 1-15). Out of 27 evaluable patients, three achieved a complete response (CR), four had a partial response (PR) (CR + PR = 26 +/- 17%), nine showed no change, and 11 had a progressive disease. Median time to progression was 83 days (range: 19-728 days). Out of 26 patients evaluable for toxicity, hematologic toxicity at day 21 was moderate: neutropenia grades 3 and 4 = 16% of cycles: two patients had grade 1 thrombopenia; and three patients, grade 3. No cumulative hematologic toxicity was detected. Nonhematologic toxicities consisted of nausea and vomiting in 72% of patients [World Health Organization (WHO) grades 3 and 4 = 8%)] and alopecia in 76% (WHO grades 2-3 = 38%). Grade 1 stomatitis occurred in 4% of cycles. Chemotherapy was discontinued in one patient because of drop of left ventricular ejection fraction (LVEF) from 0.62 to 0.44 at a cumulative IDA dosage of 322 mg/m2. The results of this study show that IDA is an active drug in elderly patients with advanced breast cancer. Due to its simplicity of administration IDA deserves further investigations in combination with other drugs.

Administration, Oral↗
PubMed1990

A randomized double-blind comparison of ondansetron and metoclopramide in the prophylaxis of emesis induced by cyclophosphamide, fluorouracil, and doxorubicin or epirubicin chemotherapy.

Seventy-five breast cancer patients scheduled to receive a first course (in a new cycle) of cyclophosphamide, fluorouracil, and doxorubicin (FAC) or epirubicin (FEC) participated in a double-blind crossover study to compare the antiemetic efficacy and safety of ondansetron (GR38032), a 5-hydroxytryptamine3 (5-HT3) receptor antagonist, and metoclopramide. Ondansetron was given as an 8 mg loading dose (4 mg intravenously [IV] plus 4 mg orally) before chemotherapy followed by 8 mg every 8 hours orally for 3 to 5 days. Metoclopramide was given as an 80 mg loading dose (60 mg IV plus 20 mg orally) before chemotherapy followed by 20 mg every 8 hours orally for 3 to 5 days. A "period" interaction in the analysis of emetic response in the first 24 hours necessitated a parallel group analysis of first treatments only, 68 patients being assessable for this parameter. In the first 24 hours, complete or major control (zero to two emetic episodes) of emesis was achieved in 30 of 35 (86%) patients receiving ondansetron and in 14 of 33 (42%) patients receiving metoclopramide (P less than .001). Ondansetron was also more effective in reducing acute nausea. On days 2 to 3, the complete or major responses were significantly better with ondansetron (81% v 65%; P = .033), but there was no statistical difference in the control of nausea. There was a significant patient preference for ondansetron (63% v 26%; P = .001). Extrapyramidal reactions were observed in two metoclopramide treatments; both treatments were otherwise well tolerated. These results are consistent with serotonin (5-HT), being a significant neurotransmitter of cyclophosphamide/doxorubicin- or epirubicin/fluorouracil-induced emesis.

Administration, Oral↗
PubMed1990

[Palliative chemotherapy of epidermoid carcinoma of the upper respiratory and digestive tracts with a combination of carboplatin and 5-fluorouracil].

One hundred and thirteen patients with advanced squamous cell cancer of the head and neck were entered into a multicenter trial. Median age was 54 yr (range: 33-74 yr). Median Karnofsky index was 70 (60-100). Thirty-five patients had had prior induction chemotherapy. The first schedule was carboplatin 300 mg/m2, dl and fluoro-uracil 1000 mg/m2/d administered in continuous IV infusion for 96 h every 4 weeks (group 1). The second schedule was carboplatin 350 mg/m2, dl and fluoro-uracil administered at the same dose every 3 weeks (group II). Median number of cycles was 3 (range: 1-16). Seven patients were not eligible. The response rate was 26% (95% confidence limits: 18-34). Nine patients had a complete response. The median duration of response was 6 months (2-16+). The response rates in the 2 groups were not statistically different (21 and 31%) but disease progression was more frequent in group I (61%) than in group II patients (25%). Six early deaths occurred, without sign of drug toxicity. Grade 2 hematological toxicity between or before any cycle was more frequent in group II patients, in particular for leucopenia (13 vs 42%, P less than 0.05). One death was related to granulopenia. Grade 2 or 3 gastric toxicity was observed in 43 patients. No other major toxicity was observed. In our study, combination therapy with carboplatin and fluoro-uracil was found to be moderately active but myelotoxic.

Adult↗
PubMed1990

[Phase II trial as 2nd line chemotherapy with 5 fluorouracil and cisplatin (5FU-CDDP) for advanced breast cancer].

Thirty patients with advanced breast cancer, previously treated with anthracycline and 5 fluorouracil in bolus administration, were evaluated with a chemotherapy regimen generally used in head and neck cancer. Treatment schedule consisted of: cisplatin 100 mg/m2 on d 1 and 5 fluorouracil 1000 mg/m2 continuous infusion on d 2-3-4-5 every 21 d. With all measurable lesions and 27 evaluable patients, the response rate was 29% (95% confidence interval: 12-47%), with 5 complete responses (3 soft tissue - 2 lung) and 3 partial responses (1 lung - 2 liver). The median duration of response is 4.5 months (range 2-11 months). The 30 patients (93 courses) are evaluable for toxicity. Hematologic toxicity was mild: anemia 68% grade 0, neutropenia 68% grade 0 and thrombocytopenia 83% grade 0. Nausea and vomiting were severe 83% grade 3 + 4 at d 1. Others side effects were mild including 5/91 mucositis grade 2 + 3, peripheral neuropathy 1/31 grade 2 and 2/91 reversible rise in serum creatinine greater than 1.5 mg/dl.

Adult↗
PubMed1990

[Acute febrile neutrophilic dermatosis (Sweet syndrome). Case report and immunohistologic study of neutrophil-associated proteolytic enzymes and their inhibitors].

A 59-year-old female patient who developed fever, headache, arthralgia and painful, raised red cutaneous plaques located predominantly on the upper trunk is presented. On the basis of the clinical and histological findings acute febrile neutrophilic dermatosis (Sweet's syndrome) was diagnosed. In affected skin we applied immunohistochemical methods to examine the topographical organization of neutrophil-associated proteinase/proteinase inhibitor systems, i.e. the PMN-elastase/alpha 1-proteinase inhibitor and the cathepsin G/alpha 1-antichymotrypsin systems. Cathepsin G, PMN-elastase and alpha 1-antichymotrypsin were found in association with the polymorphonuclear infiltrating cells, whereas alpha 1-proteinase inhibitor was localized exclusively in the subepidermal oedema. In conclusion, our immunohistological findings support the view that free PMN-elastase is involved in the pathogenesis of cutaneous lesions in Sweet's syndrome.

Dermatitis↗
PubMed1989

Dynamic interactions of c-fos protein in serum-stimulated 3T3 cells.

The c-fos gene, the cellular homologue of the transforming gene of the FBJ osteosarcoma virus, v-fos, is strongly induced in quiescent BALB/c 3T3 cells by growth factors and in other cell types by a wide variety of transmembrane signalling agents. c-fos is a member of a family of structurally related proteins which includes the fos-related antigens (fra). We have studied the dynamic state of the c-fos protein with an antibody prepared by immunizing rabbits with a plasmid-encoded fos fusion protein. In serum-stimulated BALB/c 3T3 cells, the antibody recognizes a nuclear antigen which resolves on SDS-PAGE as a 60-68-kD group of bands corresponding to c-fos, a doublet at 44-45-kD corresponding to the noncovalently associated p39 protein, as well as an approximately 50-kD band corresponding to a fra. We show that although c-fos protein synthesis is only transiently induced by serum, the c-fos protein persists within the cell after its synthesis has ceased, and it decays with a half-life of 2 hours. Significantly, newly synthesized p39 continues to appear in the immune-precipitated complex even at times when c-fos is no longer synthesized. These kinetics indicate that even following shutoff of c-fos protein synthesis, p39 is newly synthesized and can complex with c-fos protein or a fos-related antigen. During this time, c-fos also undergoes an extensive posttranslational modification. The modification is partially reversed by phosphatase treatment, which implicates protein phosphorylation. Together these results suggest that both interaction with p39 and phosphorylation may progressively modify the properties of c-fos and/or the fos-related antigens over a period of 4-8 hours following the shutoff of fos synthesis. We discuss the implications of the dynamic state of c-fos and fra protein interactions for the function of these proteins.

Animals↗
PubMed1989

[Enoxacin--comparative pharmacokinetics and tissue penetration].

The choice of an antimicrobial agent is primarily dependent on its antimicrobial activity and the pharmacokinetics in the host. The gyrase inhibitors differ in their antimicrobial spectrum as well as in their pharmacokinetics. In this review we compare key pharmacokinetic parameters of the most important 4-quinolones. Clearly, there are differences in their absorption, their sensitivity of the absorption process to food or di-or trivalent cations. On a weight basis enoxacin tends to have higher plasma levels then e.g. ciprofloxacin or norfloxacin and also tissue penetration of enoxacin as determined in the Body Fluid Model is superior to ciprofloxacin or norfloxacin. The elimination of enoxacin is mostly by the kidney (approximately 50-60% of dose) another 12-15% are metabolized in the liver. Renal failure therefore requires dose adjustments. The inhibitory effect of enoxacin on other compounds' metabolism has to be considered.

Anti-Infective Agents↗