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Biomedical subjects

P Gascón

Publications and source records attributed to P Gascón.

At least 19 recordsLinked to original sources
PubMed2006

Inhibitors of angiogenesis.

Angiogenesis and neovascularization are important mechanisms for tumor growth, progression and, subsequent metastasis. Cancer cells, as part of an inflammatory process, produce and induce multiple molecules (proangiogenic and antiangiogenic) from the surrounding stromal cells. Vascular Endothelial Growth Factor (VEGF) is the most relevant proangiogenic molecule among them. Many inhibitors of angiogenesis have been developed in the last years with the aim to block the tumor blood supply as a new anticancer strategy. Bevacizumab, an anti-VEGF, has been already approved for its use in colorectal cancer showing prolonged disease free survival as well as overall survival. It shows also important activity in breast, lung, ovarian and kidney cancer. Many others inhibitors are in advanced clinical development and show promising results as well. Current basic and clinical research in this field is generating great expectations for the future of cancer treatment.

Angiogenesis Inhibitors↗
PubMed2004

Integrating concurrent navelbine and cisplatin to hyperfractionated radiotherapy in locally advanced non-small cell lung cancer patients treated with induction and consolidation chemotherapy: feasibility and activity results.

OBJECTIVES: The purpose of this study was to determine the effectiveness and toxicity of a new combination schedule based on concurrent navelbine, cisplatin and hyperfractionated radiotherapy in patients with locally advanced NSCLC treated with platinum and gemcitabine induction and consolidation chemotherapy. MATERIALS AND METHODS: The 37 patients with pathological confirmed advanced NSCLC (non-surgical stages IIIA and IIIB) were included in the study. All of them were assessable for survival and 32 for response. The treatment schedule consisted of cisplatin (100 mg/m2) or carboplatin (400 mg/m2) on day 1 with gemcitabine (1000 mg/m2) on days 1, 8 and 15. Treatment was given every 28 days for two courses, followed by concurrent administration of accelerated modified hyperfractionated radiotherapy, with concomitant boost, with a total dose of 61.64 Gy administered for 5 weeks, with cisplatin and navelbine, for two courses, finally followed by two courses of the same initial chemotherapy. RESULTS: Four patients achieved complete response (12.5%) and 14 (44%) partial response, for an overall objective response rate of 56.5%. After a minimum follow-up duration of 35.5 months, median progression free survival was 12.2 months. The median survival was 15.4 months with actuarial 1-, 2- and 3-year survival of 67, 21 and 15%, respectively. The main toxicity was hematological. There was esophagitis (grades III and IV) in 30% of the patients and there were two treatment-related deaths. CONCLUSION: Combined treatment with concurrent radiotherapy and chemotherapy in non-surgical NSCLC is an acceptable treatment modality. However, the toxicity was not negligible.

Adult↗
PubMed2004

[Hospital registry of pancreatic tumors. Experience of the Hospital Clínic in Barcelona (Spain)].

OBJECTIVE: To describe the characteristics of patients included in the pancreatic tumor registry of the Hospital Clínic of Barcelona. PATIENTS AND METHOD: All patients with pancreatic tumors attended between July 1990 and March 2003 were registered. Data collection included: age, gender, date of diagnosis, diagnosis, histology, size, location and tumor stage, and treatment. The correlation between tumor stage and age, date of diagnosis, and tumor location was also evaluated. RESULTS: Six hundred thirty patients with pancreatic tumors were included, representing an incidence of 60 patients/year. The mean age was 66 years and the male-to-female ratio was 1,18:1. The most frequent lesion was malignant tumor of the pancreas (92%), and the most frequent histological type was pancreatic ductal adenocarcinoma (73%). The most frequent location was the head of the pancreas (64%). In 28% of the patients, pancreatic cancer was diagnosed in stage I and II. Resection was performed in 31% of patients, whereas 48% of the patients received no treatment. The ratio between local (stage I)/disseminated (stage IV) disease was 0,34. The ratio between stage I/IV increased with age, diagnosis prior to 1994, and tumor location in the head of the pancreas. CONCLUSION: Hospital tumor registries can be used to define the profile of the attended population, which can help to delineate the best diagnostic-therapeutic strategy and can be useful in clinical research.

Adult↗
PubMed2002

[Evaluation of the efficacy and efficiency of a multidisciplinary unit for the treatment of patients with colorectal cancer].

INTRODUCTION: Because of the increased complexity of the diagnostic-therapeutic approach to colorectal cancer (CRC), these patients should be managed in specialized multidisciplinary units. The aim of this study was to evaluate the efficacy and efficiency of a CRC unit (CRCU) in the diagnostic-therapeutic management of these patients. PATIENTS AND METHODS: Two groups of 50 patients with colon cancer treated in our center before and after the implementation of the CRCU were selected. Fulfillment with the protocol in terms of tumoral staging, surgical and adjuvant treatment, follow-up, interval until treatment, hospital stay, morbidity and early mortality, and the overall duration of the diagnostic-therapeutic process was analyzed. In addition, clinical workload was evaluated and a cost-minimization analysis was performed. RESULTS: The CRCU reduced the interval until surgery (20.3 12.0 vs 28.0 20.4 days; p = 0.05), hospital stay (9.8 7.7 vs 14.5 9.3 days: p = 0.01), the time to the start of adjuvant treatment (29.4 10.2 vs 39.7 19.8 days; p = 0.03) and the overall duration of the process (60.4 23,8 vs 82.1 46.1 days; p = 0.05), representing a saving of 978.85 E per patient. This improvement took place despite an increase in clinical workload (24% in 5 years in relation to the number of admissions) and had no effect on morbidity (26 vs 24%; NS) or immediate mortality (6 vs 4%; NS). CONCLUSION: Specialized multidisciplinary units increase the efficacy and efficiency of the management of patients with CRC.

Aged↗
PubMed2001

The dynamics of bone marrow stromal cells in the proliferation of multipotent hematopoietic progenitors by substance P: an understanding of the effects of a neurotransmitter on the differentiating hematopoietic stem cell.

Communication within the hematopoietic-neuroendocrine-immune axis is partly mediated by neurotransmitters (e.g. substance P, SP) and cytokines. SP mediates neuromodulation partly through the stimulation of bone marrow (BM) progenitors. This study shows that SP, through the neurokinin-1 receptor, stimulates the proliferation of primitive hematopoietic progenitors: cobblestone-forming cells (CAFC, CD34+). This effect is optimal when macrophage is included within the fibroblast support. Indirect induction of IL-1 could be important in the proliferation of CAFC colonies by SP. Phenotypic and functional studies suggest that SP might directly interact with the CD34+/CD45(dim) population. These studies indicate that SP can initiate a cascade of biological responses in the BM stroma and stem cells to stimulate hematopoiesis.

Cell Differentiation↗
PubMed2001

Induction of preprotachykinin-I and neurokinin-1 by adrenocorticotropin and prolactin. Implication for neuroendocrine-immune-hematopoietic axis.

We studied the complex interactions within the neuroendocrine-immune-hematopoietic axis by determining a possible link among ACTH, PRL, PPT-I and the receptors for its peptides, NK-1 and NK-2. Indeed, ACTH and PRL induced the expression of PPT-I and NK-1 in human bone marrow stroma with no effect on NK-2. Consistent with a role for PPT-I in regulating the development of myeloid and erythroid progenitors, we found that ACTH and PRL, through NK-1 stimulated the proliferation of both types of progenitors. Induction of PPT-I was regulated at the transcriptional and post-transcriptional levels. The results showed that ACTH and PRL stimulated the proliferation of bone marrow progenitors, partly through PPT-I and NK-1 induction.

Adrenocorticotropic Hormone↗
PubMed2000

Increased expression of preprotachykinin-I and neurokinin receptors in human breast cancer cells: implications for bone marrow metastasis.

Neuropeptides are implicated in many tumors, breast cancer (BC) included. Preprotachykinin-I (PPT-I) encodes multiple neuropeptides with pleiotropic functions such as neurotransmission, immune/hematopoietic modulation, angiogenesis, and mitogenesis. PPT-I is constitutively expressed in some tumors. In this study, we investigated a role for PPT-I and its receptors, neurokinin-1 (NK-1) and NK-2, in BC by using quantitative reverse transcription-PCR, ELISA, and in situ hybridization. Compared with normal mammary epithelial cells (n = 2) and benign breast biopsies (n = 21), BC cell lines (n = 7) and malignant breast biopsies (n = 25) showed increased expression of PPT-I and NK-1. NK-2 levels were high in normal and malignant cells. Specific NK-1 and NK-2 antagonists inhibited BC cell proliferation, suggesting autocrine and/or intercrine stimulation of BC cells by PPT-I peptides. NK-2 showed no effect on the proliferation of normal cells but mediated the proliferation of BC cells. Cytosolic extracts from malignant BC cells enhanced PPT-I translation whereas extracts from normal mammary epithelial cells caused no change. These enhancing effects may be protein-specific because a similar increase was observed for IL-6 translation and no effect was observed for IL-1alpha and stem cell factor. The data suggest that PPT-I peptides and their receptors may be important in BC development. Considering that PPT-I peptides are hematopoietic modulators, these results could be extended to understand early integration of BC cells in the bone marrow, a preferred site of metastasis. Molecular signaling transduced by PPT-I peptides and the mechanism that enhances translation of PPT-I mRNA could lead to innovative strategies for BC treatments and metastasis.

Benzamides↗
PubMed2000

Kaposi's sarcoma. New treatment modalities.

Over the last 20 years of experience with the AIDS epidemic, we have accumulated a great body of knowledge on Kaposi's sarcoma (KS), a major cause of morbidity and mortality in AIDS patients, especially among homosexual and bisexual men. New antiretroviral therapies, in particular the protease inhibitors, appear to be changing the clinical course of KS. Now, it is not unusual to observe a complete resolution and control of KS with the use of these new agents. As we have begun to unravel the pathogenesis of KS, new treatment modalities have merged targeting some of its pathogenic pathways. Although, chemotherapy remains the cornerstone of its treatment, in particular with the new liposomal preparations, new agents may soon change our approach to KS. Experimental therapies being evaluated in ongoing clinical trials include angiogenesis inhibitors, hormonal therapies, retinoic acid derivatives, and immune modulators such as interleukin 12. Better treatment for HIV, and new experimental therapies targeting the pathogenic mechanisms of KS allow us to envision the future treatment of KS with a certain degree of optimism.

Biological Products↗
PubMed2000

Penile Kaposi's sarcoma preceded by chronic penile lymphoedema.

Kaposi's sarcoma localized to the penis with striking lymphoedema is extraordinary. We report a middle-aged Haitian man who was human herpesvirus-8 seropositive, without evidence of immunosuppression or human immunodeficiency virus infection. He was first seen with Kaposi's sarcoma of 6 months duration localized to his penis, preceded by a 3-year history of chronic penile lymphoedema. His tumour regressed completely after radiotherapy. We propose that chronic lymphoedema in this patient predisposed to the development of Kaposi's sarcoma.

Humans↗
PubMed2000

Effects of preprotachykinin-I peptides on hematopoietic homeostasis. A role for bone marrow endopeptidases.

Hematopoiesis is maintained by "fine-tuned" regulation among cytokines, neuropeptides, neurotransmitters, and neurotrophic factors. Neurotransmitters, derived from PPT-I exert immune and hematopoietic regulation. PPT-I is also expressed locally in bone marrow (BM) stromal cells. PPT-I peptides induce the production of cytokines in BM cells, resulting in regulation of both committed progenitors (CFU-GM) and primitive hematopoietic progenitors (CAFC). Both types of progenitors are regulated differently by the two major PPT-I peptides, SP and NK-A. Endopeptidases, present in BM cells, can digest SP to produce SP(1-4) and SP(4-11). In this study, we investigated the hematopoietic effects of these fragments on CFU-GM and CAFC. Similar to the two major intact PPT-I peptides (SP and NK-A), we observed different hematopoietic effects by SP(1-4) and SP(4-11). Whereas SP(1-4) exerted inhibitory effects on CFU-GM and CAFC, SP(4-11) mediated stimulatory effects. Similar to NK-A, the inhibitory effects of SP(1-4) can be partly explained by the induction of suppressive cytokines (TGF-beta, TNF-alpha, and INF-gamma). Use of antagonists and screening of a dodecapeptide expression library determined that the effects of SP(1-4) were mediated by NK-1. These results show that PPT-I peptides and their endopeptidase-derived fragments may add to the fine-tuned regulation on hematopoiesis. Furthermore, PPT-I may be exerting autoregulation to protect hematopoietic stem cells. These studies have relevance to stem cell protection and BM transplant.

Adult↗
PubMed1998

Systemic transforming growth factor-beta in patients with bone marrow fibrosis--pathophysiological implications.

Idiopathic myelofibrosis (IMF) and secondary myelofibrosis (MF) are characterized by bone marrow (BM) fibrosis, neoangiogenesis, and increased extracellular matrix (ECM) proteins. These characteristics may be partially attributed to transforming growth factor beta (TGF-beta), a cytokine produced by monocytes. In myelofibrosis, monocytes are increased and activated with concomitant up-regulation of intracytoplasmic TGF-beta. We have therefore determined systemic TGF-beta in patients with either BM fibrosis: IMF, n = 18; MF, n = 16; or without BM fibrosis: hematologic disorders with normal platelets (n = 31); high platelets (n = 9); or normal controls (n = 27). Compared with nonfibrosis sera, there was significant TGF-beta elevation in BM fibrosis sera (P < 0.0001). Most (>80%) of the TGF-beta is active and belongs to the-beta1 isoform. In situ hybridization and immunohistochemical analyses in BM biopsy sections showed a marked increase in TGF-beta1 only in patients with fibrosis. Moreover, TGF-beta protein was detected mainly in myelomonocytic-like predominant areas. To determine if another functionally similar cytokine, basic fibroblast growth factor (bFGF), may be important to BM fibrosis, we quantitated sera levels and found elevation in 57% compared with 100% elevation for TGF-beta. The data indicate that irrespective of etiology, systemic TGF-beta is elevated in patients with BM fibrosis. TGF-beta likely plays an important role in the development of BM fibrosis. The study also provides a significant parameter for early therapeutic intervention in BM fibrosis.

Adult↗
PubMed1997

Receptor induction regulates the synergistic effects of substance P with IL-1 and platelet-derived growth factor on the proliferation of bone marrow fibroblasts.

The neuropeptide substance P (SP) stimulates CFU in bone marrow (BM) cultures. Although the methylcellulose matrix used in these assays does not provide an appropriate substratum to support adherent-dependent cells, we have observed that cultures containing optimal SP (10(-8)-10(-10) M) develop confluent areas of reticular/fibroblastoid-like cells with CFUs predominantly localized within their vicinity. Characterization (cytochemical and immunofluorescence) of the reticular/fibroblastoid-like cells indicated that they were fibroblasts, the major constituent of the BM stroma. Hemopoietic effects by SP are mediated by the stroma that expresses SP receptors. We studied the effects of SP (10(-7)-10(-11) M) with suboptimal platelet-derived growth factor-BB (PDGF-BB; 5 ng/ml) and IL-1alpha (2 ng/ml), two fibrogenic cytokines, and also hemopoietic regulators. SP by itself and in synergy with either cytokine induced fibroblast proliferation. At optimum SP, IL-1alpha induced 1.6 times the proliferation of PDGF-BB (87 +/- 7 vs 55 +/- 5; n = 12; p < 0.05). The effects of SP were blunted by a specific neurokinin-1 antagonist. Scatchard analysis indicated that SP binds to BM fibroblasts with an approximate Kd of 5 nM. SP induced steady state mRNA for IL-1 receptor IL-1RI and PDGF-BB (PDGF-AR, PDGF-BR) receptors by 7.5-, 6.2-, and 10.5-fold, respectively. Their up-regulation may be partly responsible for the synergistic effects of SP and their ligands. Induction (3-fold) of neurokinin-1 mRNA by IL-1alpha compared with no induction by PDGF-BB may explain the preferred synergism between SP and IL-1alpha. This study indicates that induction of SP, IL-1alpha, and PDGF-BB receptors is important to their synergistic effects on BM fibroblast proliferation. These results bring new insights into stroma-mediated hemopoietic regulation.

Animals↗
PubMed1997

Hematopoietic modulation by the tachykinins.

We have been studying hematopoietic effects by the tachykinins, which like many other neuropeptides can be expressed in neural and nonneural tissues. Substance P (SP) and neurokinin-A (NK-A), members of the tachykinins are immune and hematopoietic modulators. SP and NK-A are derived from the preprotachykinin-I gene (PPT-I) through alternate splicing and posttranslational modification. In the bone marrow (BM), nerve fibers provide a source of neural SP and the stroma provides a source of nonneural SP. The tachykinins interact with each of three cloned neurokinin (NK) receptors (NK-1R, NK-2R, NK-3R) with SP and NK-A exhibiting binding preferences for NK-1R and NK-2R, respectively. Proliferation of myeloid progenitors (CFU-GM) is differentially regulated by SP and NK-A. The former enhances the proliferation whereas the latter is inhibitory. The BM stroma mediates most of the hematopoietic effects exerted by SP and NK-A partly through the induction of cytokines. The proliferative effects of SP correlate with the induction of positive hematopoietic growth factors such as IL-3, IL-6, GM-CSF and c-kit ligand and the inhibitory effects by NK-A correlate with the induction of two negative hematopoietic regulators, MIP-1 alpha and TGF-beta. Intracellular signals mediated by NK-1R and NK-2R are part of the mechanism responsible for tachykinin-mediated regulation of hematopoiesis. The stimulatory effects on BM progenitors mediated by NK-1R can be partly inhibited by NK-2R activation. IL-1 and other cytokines induced by SP in BM stroma modulate NK-1R induction. Furthermore, SP can induce IL-1 type I receptor in stroma. Together, these data suggest that the tachykinins and the cytokines interact to regulate hematopoiesis. These interactions contribute to hematopoietic regulation by mechanisms that involve induction of: (1) tachykinins and cytokines by each other; (2) NK-1R by cytokines and (3) cytokine receptor by the tachykinins. These studies emphasize that in terms of hematopoiesis, the cytokines and neuropeptides are not mutually exclusive factors and thus, the hematopoietic regulatory network would be incomplete without the role of neuropeptides being considered.

Animals↗
PubMed1997

Hematopoietic regulation mediated by interactions among the neurokinins and cytokines.

This review summarizes the current data regarding the mechanisms by which two mammalian neurokinins (tachykinins), substance P (SP) and neurokinin-A (NK-A) are involved in hematopoiesis. SP and NK-A are derived from the preprotachykinin-I (PPT-I) gene which can be induced by cytokines and neurotrophic factors. In the bone marrow (BM), nerve fibers and stroma are potential sources for the PPT-I gene products. SP and NK-A interact with either of three cloned receptors, neurokinin-1 (NK-1), NK-2 or NK-3, although SP and NK-A exhibit binding preferences for NK-1 and NK-2 respectively. Through specific receptors, SP and NK-A exert dichotomous hematopoietic effects mediated mostly by the BM stroma. SP enhances the proliferation of primitive BM stem cells and progenitors and these effects correlate with the induction of stimulatory hematopoietic growth factors. NK-A appears to be protective to stem cells through the induction of TGF-beta. Proliferation of myeloid progenitors is inhibited by NK-A, effects which correlate with the induction of two suppressive factors, TGF-beta and MIP-1alpha. Stimulation of NK-2 leads to partial blunting of the enhanced stimulatory effects mediated by NK-1. Furthermore, stimulatory hematopoietic cytokines upregulate NK-1 expression and downregulate the constitutively expressed NK-2 in BM stroma. Together, the experimental evidence suggests that NK-A-NK-2 interactions could be a feedback to hematopoietic stimulation. Expression of NK-1 and NK-2 in CD34+ cell lines and also, the presence of SP binding sites on primary CD34+ cells suggest that the neurokinins could be interacting directly with BM progenitors and stem cells. In BM stroma, cytokines and neurokinins regulate the expression of each other and also, their respective receptors. In summary, the current literature pertaining to hematopoietic regulation indicates the involvement of a complex network that includes, but not exclusive of the cytokines and neurokinins. The current models that pertain to stem cell proliferation and differentiation should therefore add neuropeptides to the list of hematopoietic modulators.

Animals↗
PubMed1996

Enhanced HIV-1 activity in bone marrow can lead to myelopoietic suppression partially contributed by gag p24.

Similar to other lymphoid organs, the bone marrow (BM) is a potential reservoir for HIV-1. Although hematologic abnormalities are common in AIDS patients, the mechanisms by which HIV-1 contributes to these abnormalities are poorly understood. Hemapoietic suppression can be mediated by HIV-1 and some of its associated proteins. We have previously reported that AIDS peripheral blood sera inhibit normal CFU-granulocyte macrophage (GM). In this study, we have found that sera obtained from AIDS BM patients are more inhibitory to CFU-GM than those from peripheral blood (p < 0.05). To determine a candidate suppressor factor, we studied the role of p24 and found that it exerts varying degrees of suppression to CFU-GM, but minimal inhibition on erythroid colonies. We have found that the suppressive levels of p24 in in vitro assays are similar to the average circulating levels in AIDS patients. We have also observed that most of the inhibition caused by p24 is mediated by soluble factor(s) produced by the BM stroma. Cross-linking studies with membrane proteins from normal BM stroma and CD34+ cells indicated a putative 26-kDa p24 receptor, indicating that p24 binds to a receptor present on normal BM cells. These results implicate another HIV-1 protein, p24, in hemapoietic suppression and add another plausible mechanism by which HIV-1 contributes to BM failure in AIDS. Furthermore, these findings suggest a potential risk for similar in vivo suppression in the early phase of HIV-1 infection when viremia is elevated, and also in long-term survivors who have low, although persistent, HIV-1 replication.

Acquired Immunodeficiency Syndrome↗