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Biomedical subjects

B M Colombo

Publications and source records attributed to B M Colombo.

At least 19 recordsLinked to original sources
PubMed2005

Asthma in women with endometriosis.

INTRODUCTION: This study aimed to investigate asthma prevalence and severity in women with and without endometriosis. METHODS: Before laparoscopy, asthma prevalence was evaluated in 879 women of reproductive age, undergoing surgery because of benign gynaecological conditions. Diagnosis of bronchial asthma was based on the American Thoracic Society criteria; asthma severity was classified in four categories according to the 2002 Global Initiative for Asthma guidelines. Asthmatic patients completed the Living with Asthma Questionnaire (LWAQ). Endometriosis was confirmed histologically and classified according to the revised American Fertility Society criteria. RESULTS: There were no significant differences in age, smoking status, and other demographic and health characteristics between patients with endometriosis (n = 467) and controls (n = 412). Asthma prevalence was similar in women with (23/467, 4.9%; 95% CI, 3.1-7.3) and without (22/412, 5.3%; 95% CI, 3.4-8.0; P = 0.781) endometriosis. Asthma severity was similar in women with and without endometriosis, with 12 (52.2%) women with endometriosis and 13 (59.1%) controls being in the intermittent (mildest) degree of severity. No significant difference was observed between women with and without endometriosis in the LWAQ total score. CONCLUSIONS: Women with endometriosis do not have an increased risk of having asthma.

Adult↗
PubMed2003

Peripartum cardiomyopathy. A review.

The objective of this article is to review the aetiology, epidemiology, diagnosis, clinical course, treatment and prognosis of peripartum cardiomyopathy (PPCM). The medical literature from 1966 to March 2002 was reviewed through MEDLINE. PPCM is a rare complication in pregnancy. It is seen in late pregnancy or in the early puerperium. The aetiology of this disease remains uncertain. Many possible causes have been proposed, including myocarditis, abnormal immune response to pregnancy, maladaptive response to the hemodynamic stresses of pregnancy and prolonged tocolysis. Risk factors for PPCM include advanced maternal age, multiparity, African descent, twinning and long-term tocolysis. Patients with systolic dysfunction during pregnancy are treated the same as patients who are not pregnant. The mainstays of medical therapy are digoxin, loop diuretics, sodium restriction and afterload reducing agents (hydralazine and nitrates). Due to a high risk for venous and arterial thrombosis, anticoagulation with heparin should be instituted. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers should be avoided during pregnancy because of severe adverse neonatal effects. The utility of immunosuppressive therapy remains ambiguous. Advances in medical therapy for dilated cardiomyopathy and cardiac transplantation have significantly improved the quality of life and survival for patients.

Cardiomyopathies↗
PubMed2002

Mxi1 inhibits the proliferation of U87 glioma cells through down-regulation of cyclin B1 gene expression.

Mxi1 is a Mad family member that plays a role in cell proliferation and differentiation. To test the role of Mxi1 on tumorigenesis of glioma cells we transfected a CMV-driven MXI1 cDNA in U87 human glioblastoma cells. Two clones were isolated expressing MXI1 levels 18- and 3.5-fold higher than wild-type U87 cells (clone U87.Mxi1.14 and U87.Mxi1.22, respectively). In vivo, U87.Mxi1.14 cells were not tumorigenic in nude mice and delayed development of tumours was observed with U87.Mxi1.22 cells. In vitro, the proliferation rate was partially and strongly inhibited in U87.Mxi1.22 and U87.Mxi1.14 cells respectively. The cell cycle analysis revealed a relevant accumulation of U87.Mxi1.14 cells in the G(2)/M phase. Interestingly, the expression of cyclin B1 was inhibited to about 60% in U87.Mxi1.14 cells. This inhibition occurs at the transcriptional level and depends, at least in part, on the E-box present on the cyclin B1 promoter. Consistent with this, the endogenous Mxi1 binds this E-box in vitro. Thus, our findings indicate that Mxi1 can act as a tumour suppressor in human glioblastomas through a molecular mechanism involving the transcriptional down-regulation of cyclin B1 gene expression.

Basic Helix-Loop-Helix Proteins↗
PubMed2001

Protection of mice against leukemia after vaccination with bone marrow-derived dendritic cells loaded with apoptotic leukemia cells.

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that need to be activated before they can function to initiate primary and secondary immune responses in vivo. DCs are also specialized to maintain peripheral tolerance to self after uptake of apoptotic material, likely corresponding to both apoptotic bodies and whole apoptotic cells. Here, we report that murine bone marrow-derived DCs can be activated in vitro by exogenous signals received from apoptotic leukemia cells expressing on the cell surface a model tumor-associated antigen. Injected in vivo, these exogenously activated DCs can function as adjuvants to protect mice against leukemia by stimulating an antigen-specific cellular-mediated cytotoxic immune response. To our knowledge, this is the first report indicating that DCs loaded with apoptotic leukemia cells protect mice against leukemia development.

Animals↗
PubMed2000

Cellular but not humoral immune responses generated by vaccination with dendritic cells protect mice against leukaemia.

Dendritic cells (DC) are extremely efficient at generating both prophylactic and therapeutic anti-tumour immunity. We aimed to analyse the respective roles of humoral and cellular immune responses generated in mice vaccinated with bone marrow (BM)-derived DC in terms of in vivo anti-leukaemia effect. We used the murine L1210 B lymphocytic leukaemia genetically modified to express on the cell surface of human CD4 (hCD4) (L1210/hCD4) as a model tumour-associated antigen (TAA). DC cultures were loaded with either purified soluble hCD4 (shCD4) protein or unfractionated L1210/hCD4 extracts and injected as vaccine into mice. The efficacy of these vaccinations was compared with that of vaccination with shCD4 protein emulsified in Freund's adjuvant (FA). We evaluated the immune responses generated after these vaccinal protocols and the survival rate of vaccinated mice subsequently challenged with a lethal injection of L1210/hCD4 cells. Our results demonstrated that vaccination with shCD4 protein or tumour extract-loaded DC mainly generated an hCD4 antigen-specific cell-mediated cytotoxic immune response that was associated with a specific protection against leukaemia. In contrast, vaccination with the protein emulsified in FA only generated potent humoral immune responses that were not protective against leukaemia. Altogether, our results indicate that the unique property of loaded DC to trigger an anti-leukaemia protective effect is mainly associated with cellular immune responses.

Animals↗
PubMed1999

Immunophenotypical and functional heterogeneity of dendritic cells generated from murine bone marrow cultured with different cytokine combinations: implications for anti-tumoral cell therapy.

Dendritic cells (DC) are professional antigen-presenting cells that can be used as immune adjuvant for anti-tumoural therapies. This approach requires the generation of large quantities of DC that are fully characterized on the immunophenotypical and functional levels. In a murine model, we analysed the in vitro effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) alone or combined with interleukin-4 (IL-4) or Flt3 ligand (Flt3-L) on the number, immunophenotype and functions of bone marrow-derived DC. In GM-CSF cultures, we have identified two populations based on their level of expression of major histocompatibility complex (MHC) class II molecules: MHC-IIhi cells, exhibiting the typical morphology and immunophenotype of myeloid DC (CD11c+ 33D1+ DEC-205+ F4/80+), and MHC-IIlo cells, heterogeneous for DC markers (30% CD11c+; 50% 33D1+; DEC-205-; F4/80+). The addition of Flt3-L to GM-CSF induced a twofold increase in MHC-IIhi DC number; besides, the MHC-IIlo cells lost all DC markers. In contrast, after addition of IL-4 to GM-CSF, the two populations displayed a very similar phenotype (CD11c+ 33D1- DEC-205+ F4/80-), differing only in their expression levels of MHC class II and costimulatory molecules, and showed similar stimulatory activity in mixed leucocyte reaction. We next analysed the migration of these cultured cells after fluorescent labelling. Twenty-four hours after injection into the footpads of mice, fluorescent cells were detected in the draining popliteal lymph nodes, with an enhanced migration when cells were cultured with GM-CSF+Flt3-L. Finally, we showed that MHC-IIhi were more efficient than MHC-IIlo cells in an anti-tumoral vaccination protocol. Altogether, our data highlight the importance of characterizing in vitro-generated DC before use in immunotherapy.

Animals↗
PubMed1998

In vitro and in vivo effects of retrovirus-mediated transfer of the connexin 43 gene in malignant gliomas: consequences for HSVtk/GCV anticancer gene therapy.

In tumors, gap junctional intercellular communication (GJIC) is usually down-regulated and the expression of connexins, membrane proteins constituting gap junction channels, is often low or altered. GJIC, allowing the intercellular diffusion of ganciclovir (GCV) triphosphate, is also one mediator of the 'bystander effect', the phenomenon by which herpes simplex virus thymidine kinase (HSVtk)-transduced, neoplastic cells kill surrounding HSVtk-negative cells when treated with GCV. We set up experiments to evaluate the effects of retrovirus-mediated in vivo gene transfer of connexin 43 in malignancies with low GJIC capacity. We found that U-87 human glioblastoma cells transfected in vitro by the human Cx43 cDNA grow significantly more slowly than control U-87 cells and lose their tumorigenicity when injected subcutaneously in nude mice. When the Cx43 gene was transduced in vitro in U-87 cells by a retroviral producer cell line (N3.2.ii, titer 1.5 x 10(6) c.f.u./ml) in vivo results were similar. However, only when U-87 cells were co-injected with N3.2.ii cells in nude mice in a 1:5 ratio, a 50% reduction in tumor size was obtained during the first 3 weeks. Moreover the coinjection of U-87 cells with N3.2.ii and SBA cells (a retroviral producer cell line expressing the HSVtk gene), was not able to potentiate the effects of GCV administration, suggesting that Cx43 gene transfer requires more efficient vectors to increase the bystander effect in vivo.

Animals↗
PubMed1997

Limited efficacy of the HSV-TK/GCV system for gene therapy of malignant gliomas and perspectives for the combined transduction of the interleukin-4 gene.

The growth of U-87 or C6 gliomas co-implanted in nude mice with retroviral producer cells (VPC) expressing the herpes simplex virus-thymidine kinase (HSV-tk) gene is only partially impaired by treatment with ganciclovir (GCV). The effect of GCV is even less evident when C6 and VPC are co-implanted into the rat brain. Furthermore, tumors from C6 cells carrying the HSV-tk gene are not eradicated by GCV, although they remain sensitive to GCV when replated in vitro. These limits of the HSV-tk/GCV system in glioma gene therapy may be due to insufficient gene transfer and/or insufficient delivery of GCV to glioma cells. Combination of HSV-tk and one or more cytokines may improve the antitumor efficacy. Among cytokines, interleukin-4 (IL-4) has already been shown to be active against gliomas. In nude mice, GCV treatment inhibited tumor growth more effectively after co-injection of C6 cells with a mixture of VPC transducing IL-4 and HSV-tk genes than after co-injection with either IL-4 or HSV-tk VPC only. In immunocompetent Sprague-Dawley rats, co-injection of IL-4 VPC and C6 cells was also effective in inhibiting the growth of C6 brain tumors, 38% of the animals surviving for at least 2 months. Furthermore, increased and prolonged antitumor efficacy was obtained by transducing both IL-4 and HSV-tk genes.

Animals↗
PubMed1996

Deletion mapping of gliomas suggest the presence of two small regions for candidate tumor-suppressor genes in a 17-cM interval on chromosome 10q.

The loss of genetic material on chromosome 10q is frequent in different tumors and particularly in malignant gliomas. We analyzed 90 of these tumors and found loss of heterozygosity (LOH) in >90% of the informative loci in glioblastoma multiforme (GBM). Initial studies restricted the common LOH region to 10q24-qter. Subsequently, the study of a pediatric GBM suggested D10S221 and D10S209, respectively, as centromeric and telomeric markers of a 4-cM LOH region. It is interesting to note that, in one subset of cells from this tumor, locus D10S209 seems involved in the allelic imbalance of a larger region, with D10S214 as telomeric marker. This 17-cM region contains the D10S587-D10S216 interval of common deletion recently defined on another set of gliomas.

Brain Neoplasms↗
PubMed1995

The "bystander effect": association of U-87 cell death with ganciclovir-mediated apoptosis of nearby cells and lack of effect in athymic mice.

Cells expressing the herpes simplex-thymidine kinase (HS-TK) gene as a consequence of retroviral transduction, as well as TK-negative (TK-) bystander cells, can be killed by treatment with ganciclovir (GCV). In vitro, this "bystander effect," has been attributed to metabolic cooperation through gap junctions or to the uptake of apoptotic vesicles. We show that GCV treatment kills TK-negative U-87 glioma cells cocultured with cells that express TK (TK+) but that have lost the capacity for releasing retroviral particles. A photometric enzyme immunoassay identifies histone-associated DNA fragments, typical of apoptosis, in the cytosol of GCV-treated TK+ cells, and apoptotic features are also demonstrated by ultrastructural studies. Northern blot analysis and the reverse transcription polymerase chain reaction (PCR) show that connexin 43, a major constituent of gap junctions, is expressed in TK+ and U-87 cells. The size of U-87 tumors in nude mice subsequently injected with TK+ cells and GCV is not significantly different than in untreated animals; whereas, after injecting 1:1 mixtures of U-87 and TK+ cells, GCV treatment only causes a temporary regression of tumor growth. On the contrary, when the injected mixtures contain PA317.STK.SBA (a retroviral producer cell line that can transduce efficiently the HS-TK gene) and U-87 cells, tumors are destroyed effectively by GCV treatment. Thus, an experimental setting in which U-87 gliomas are matched with cells that are able to express, but not to transduce, the HS-TK gene indicates that the bystander effect kills U-87 cells in vitro by mechanisms associated with apoptotic death. In vivo, this effect is not sufficient to restrain the tumor growth taking place in immunodeficient animals.

Animals↗
PubMed1994

Increasing complexity of the karyotype in 50 human gliomas. Progressive evolution and de novo occurrence of cytogenetic alterations.

We studied the karyotypes of eight differentiated gliomas, 19 anaplastic gliomas, and 23 glioblastomas (GBM). Normal stemlines were present in 70% of the differentiated and anaplastic gliomas; abnormalities were mostly characterized by loss of sex chromosomes. In GBM, on the contrary, only 13% of the stemlines were normal and three groups, 45,XO, near-diploid, and near tetraploid, could be identified. The most frequent alterations among GBM were: total or partial loss of chromosome 10 in nine cases, structural abnormalities of chromosome 9 in seven cases, and loss of the Y chromosome in stemline clones of seven cases. Less frequent abnormalities included chromosomes 7, 1, 3, and 19. Our data support the cytogenetic model of gliomas as multi-stage tumors. GBM, in particular, can originate from the evolution of astrocytomas but can also develop de novo. In both cases loss of genetic material on chromosome 10 seems to play a crucial role.

Adult↗
PubMed1994

p53 mutations and microsatellite analysis of loss of heterozygosity in malignant gliomas.

We have studied alterations of the p53 gene in 27 patients with malignant gliomas. Loss of heterozygosity (LOH) was investigated by microsatellite analysis in 23 patients (22 informative) and detected in nine. Exons 5 through 9 were amplified by polymerase chain reaction (PCR) in these nine patients: alterations were found in five cases (three missense mutations, one non-sense mutation, and one putative deletion), while in four the DNA sequence was normal. In the four patients where LOH could not be studied, the p53 sequence from tumor DNA was normal. These results indicate that microsatellite analysis is a convenient tool for LOH detection at the p53 locus and that mutations of the p53 gene are present in only part of the patients with LOH, implying the possibility that another tumor suppressor gene is located in the proximity of the p53 locus.

Adult↗
PubMed1991

Expression of the pp63 gene encoding the insulin receptor tyrosine kinase inhibitor in proliferating liver and in liver tumors.

After partial hepatectomy in rats, a approximately 4-fold decrease in pp63 mRNA level was detected at 24 h, but not at earlier time points. In mice, during liver cell proliferation induced by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene and phenobarbital, pp63 transcript levels had a decrease of 40-50%. However, pp63 mRNA was 5-6 fold higher in murine hepatocellular tumors than in normal adult mouse liver.

Animals↗
PubMed1991

Incidence of mutations at codon 61 of the Ha-ras gene in liver tumors of mice genetically susceptible and resistant to hepatocarcinogenesis.

By selective oligonucleotide hybridization of polymerase chain reaction (PCR) amplified tumor DNAs we have analysed the incidence of mutations at codon 61 of the Ha-ras gene in 42 liver tumors spontaneously developed in Balb/c, C3Hf and B6C3 male mice, and in 79 liver tumors induced by the chemical carcinogens diethylnitrosamine (NDEA) and urethan in B6C3 and B6C male and female mice. The incidence of Ha-ras gene mutations in both spontaneously developed and urethan-induced liver tumors was 50%-63% in mice genetically susceptible to hepatocarcinogenesis (C3Hf, B6C3) and 7%-9% in mice genetically resistant (Balb/c, B6C). Urethan-induced tumors showed about the same incidence of ras mutations in male and in female B6C3 mice. NDEA-induced tumors showed a low incidence of Ha-ras mutations in both the hybrid mice (3/18 and 1/13 in B6C3 and B6C male mice, respectively). The most frequently found mutations were a C----A transversion at the 1st base of codon 61 in spontaneous tumors, and an A----T transversion at the 2nd base in urethan-induced tumors. Our results indicate that liver tumors induced by NDEA or urethan or spontaneously arisen have a different pattern of Ha-ras mutations at codon 61 and that these mutations constitute a rare molecular alteration in the pathogenesis of liver tumors in genetically resistant mice.

Animals↗
PubMed1989

Major urinary protein as a negative tumor marker in mouse hepatocarcinogenesis.

A cDNA clone isolated by differential screening of a mouse liver cDNA library using RNA probes from normal adult liver and from hepatocellular tumors showed, on northern blot analysis, a single transcript of 1 kb present at high levels in normal adult mouse liver but at 15- to 100-fold reduced levels in spontaneous and p-dimethylaminoazobenzene- or urethan-induced liver tumors. The transcript, which was absent in two-wk-old mouse liver, is coded by a developmentally regulated gene. Nucleotide sequence analysis demonstrated that the isolated clone encoded a major urinary protein (MUP). Immunocytochemistry analysis, using a goat antibody to MUP on histologic liver sections containing diethylnitrosamine-induced liver nodules, showed that the decrease in MUP levels also occurred in microscopic nodules. Therefore, MUP decrease represents an early event in the development of mouse liver tumors, and it may be used as a tumor marker in mouse hepatocarcinogenesis.

Alpha-Globulins↗